Source file src/cmd/compile/internal/ssagen/ssa.go

     1  // Copyright 2015 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package ssagen
     6  
     7  import (
     8  	"bufio"
     9  	"bytes"
    10  	"cmp"
    11  	"fmt"
    12  	"go/constant"
    13  	"html"
    14  	"internal/buildcfg"
    15  	"internal/goexperiment"
    16  	"internal/runtime/gc"
    17  	"os"
    18  	"path/filepath"
    19  	"slices"
    20  	"strings"
    21  
    22  	"cmd/compile/internal/abi"
    23  	"cmd/compile/internal/base"
    24  	"cmd/compile/internal/ir"
    25  	"cmd/compile/internal/liveness"
    26  	"cmd/compile/internal/objw"
    27  	"cmd/compile/internal/reflectdata"
    28  	"cmd/compile/internal/rttype"
    29  	"cmd/compile/internal/ssa"
    30  	"cmd/compile/internal/staticdata"
    31  	"cmd/compile/internal/typecheck"
    32  	"cmd/compile/internal/types"
    33  	"cmd/internal/obj"
    34  	"cmd/internal/objabi"
    35  	"cmd/internal/src"
    36  	"cmd/internal/sys"
    37  
    38  	rtabi "internal/abi"
    39  )
    40  
    41  var ssaConfig *ssa.Config
    42  var ssaCaches []ssa.Cache
    43  
    44  var ssaDump string     // early copy of $GOSSAFUNC; the func name to dump output for
    45  var ssaDir string      // optional destination for ssa dump file
    46  var ssaDumpStdout bool // whether to dump to stdout
    47  var ssaDumpCFG string  // generate CFGs for these phases
    48  const ssaDumpFile = "ssa.html"
    49  
    50  // ssaDumpInlined holds all inlined functions when ssaDump contains a function name.
    51  var ssaDumpInlined []*ir.Func
    52  
    53  // Maximum size we will aggregate heap allocations of scalar locals.
    54  // Almost certainly can't hurt to be as big as the tiny allocator.
    55  // Might help to be a bit bigger.
    56  const maxAggregatedHeapAllocation = 16
    57  
    58  func DumpInline(fn *ir.Func) {
    59  	if ssaDump != "" && ssaDump == ir.FuncName(fn) {
    60  		ssaDumpInlined = append(ssaDumpInlined, fn)
    61  	}
    62  }
    63  
    64  func InitEnv() {
    65  	ssaDump = os.Getenv("GOSSAFUNC")
    66  	ssaDir = os.Getenv("GOSSADIR")
    67  	if ssaDump != "" {
    68  		if strings.HasSuffix(ssaDump, "+") {
    69  			ssaDump = ssaDump[:len(ssaDump)-1]
    70  			ssaDumpStdout = true
    71  		}
    72  		spl := strings.Split(ssaDump, ":")
    73  		if len(spl) > 1 {
    74  			ssaDump = spl[0]
    75  			ssaDumpCFG = spl[1]
    76  		}
    77  	}
    78  }
    79  
    80  func InitConfig() {
    81  	types_ := ssa.NewTypes()
    82  
    83  	if Arch.SoftFloat {
    84  		softfloatInit()
    85  	}
    86  
    87  	// Generate a few pointer types that are uncommon in the frontend but common in the backend.
    88  	// Caching is disabled in the backend, so generating these here avoids allocations.
    89  	_ = types.NewPtr(types.Types[types.TINTER])                             // *interface{}
    90  	_ = types.NewPtr(types.NewPtr(types.Types[types.TSTRING]))              // **string
    91  	_ = types.NewPtr(types.NewSlice(types.Types[types.TINTER]))             // *[]interface{}
    92  	_ = types.NewPtr(types.NewPtr(types.ByteType))                          // **byte
    93  	_ = types.NewPtr(types.NewSlice(types.ByteType))                        // *[]byte
    94  	_ = types.NewPtr(types.NewSlice(types.Types[types.TSTRING]))            // *[]string
    95  	_ = types.NewPtr(types.NewPtr(types.NewPtr(types.Types[types.TUINT8]))) // ***uint8
    96  	_ = types.NewPtr(types.Types[types.TINT16])                             // *int16
    97  	_ = types.NewPtr(types.Types[types.TINT64])                             // *int64
    98  	_ = types.NewPtr(types.ErrorType)                                       // *error
    99  	_ = types.NewPtr(reflectdata.MapType())                                 // *internal/runtime/maps.Map
   100  	_ = types.NewPtr(deferstruct())                                         // *runtime._defer
   101  	types.NewPtrCacheEnabled = false
   102  	ssaConfig = ssa.NewConfig(base.Ctxt.Arch.Name, *types_, base.Ctxt, base.Flag.N == 0, Arch.SoftFloat)
   103  	ssaConfig.Race = base.Flag.Race
   104  	ssaCaches = make([]ssa.Cache, base.Flag.LowerC)
   105  
   106  	// Set up some runtime functions we'll need to call.
   107  	ir.Syms.AssertE2I = typecheck.LookupRuntimeFunc("assertE2I")
   108  	ir.Syms.AssertE2I2 = typecheck.LookupRuntimeFunc("assertE2I2")
   109  	ir.Syms.CgoCheckMemmove = typecheck.LookupRuntimeFunc("cgoCheckMemmove")
   110  	ir.Syms.CgoCheckPtrWrite = typecheck.LookupRuntimeFunc("cgoCheckPtrWrite")
   111  	ir.Syms.CheckPtrAlignment = typecheck.LookupRuntimeFunc("checkptrAlignment")
   112  	ir.Syms.Deferproc = typecheck.LookupRuntimeFunc("deferproc")
   113  	ir.Syms.Deferprocat = typecheck.LookupRuntimeFunc("deferprocat")
   114  	ir.Syms.DeferprocStack = typecheck.LookupRuntimeFunc("deferprocStack")
   115  	ir.Syms.Deferreturn = typecheck.LookupRuntimeFunc("deferreturn")
   116  	ir.Syms.Duffcopy = typecheck.LookupRuntimeFunc("duffcopy")
   117  	ir.Syms.Duffzero = typecheck.LookupRuntimeFunc("duffzero")
   118  	ir.Syms.GCWriteBarrier[0] = typecheck.LookupRuntimeFunc("gcWriteBarrier1")
   119  	ir.Syms.GCWriteBarrier[1] = typecheck.LookupRuntimeFunc("gcWriteBarrier2")
   120  	ir.Syms.GCWriteBarrier[2] = typecheck.LookupRuntimeFunc("gcWriteBarrier3")
   121  	ir.Syms.GCWriteBarrier[3] = typecheck.LookupRuntimeFunc("gcWriteBarrier4")
   122  	ir.Syms.GCWriteBarrier[4] = typecheck.LookupRuntimeFunc("gcWriteBarrier5")
   123  	ir.Syms.GCWriteBarrier[5] = typecheck.LookupRuntimeFunc("gcWriteBarrier6")
   124  	ir.Syms.GCWriteBarrier[6] = typecheck.LookupRuntimeFunc("gcWriteBarrier7")
   125  	ir.Syms.GCWriteBarrier[7] = typecheck.LookupRuntimeFunc("gcWriteBarrier8")
   126  	ir.Syms.Goschedguarded = typecheck.LookupRuntimeFunc("goschedguarded")
   127  	ir.Syms.Growslice = typecheck.LookupRuntimeFunc("growslice")
   128  	ir.Syms.GrowsliceBuf = typecheck.LookupRuntimeFunc("growsliceBuf")
   129  	ir.Syms.GrowsliceBufNoAlias = typecheck.LookupRuntimeFunc("growsliceBufNoAlias")
   130  	ir.Syms.GrowsliceNoAlias = typecheck.LookupRuntimeFunc("growsliceNoAlias")
   131  	ir.Syms.MoveSlice = typecheck.LookupRuntimeFunc("moveSlice")
   132  	ir.Syms.MoveSliceNoScan = typecheck.LookupRuntimeFunc("moveSliceNoScan")
   133  	ir.Syms.MoveSliceNoCap = typecheck.LookupRuntimeFunc("moveSliceNoCap")
   134  	ir.Syms.MoveSliceNoCapNoScan = typecheck.LookupRuntimeFunc("moveSliceNoCapNoScan")
   135  	ir.Syms.InterfaceSwitch = typecheck.LookupRuntimeFunc("interfaceSwitch")
   136  	for i := 1; i < len(ir.Syms.MallocGCSmallNoScan); i++ {
   137  		ir.Syms.MallocGCSmallNoScan[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcSmallNoScanSC%d", i))
   138  	}
   139  	for i := 1; i < len(ir.Syms.MallocGCSmallScanNoHeader); i++ {
   140  		ir.Syms.MallocGCSmallScanNoHeader[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcSmallScanNoHeaderSC%d", i))
   141  	}
   142  	for i := 1; i < len(ir.Syms.MallocGCTiny); i++ {
   143  		ir.Syms.MallocGCTiny[i] = typecheck.LookupRuntimeFunc(fmt.Sprintf("mallocgcTinySize%d", i))
   144  	}
   145  	ir.Syms.MallocGC = typecheck.LookupRuntimeFunc("mallocgc")
   146  	ir.Syms.Memmove = typecheck.LookupRuntimeFunc("memmove")
   147  	ir.Syms.Memequal = typecheck.LookupRuntimeFunc("memequal")
   148  	ir.Syms.Msanread = typecheck.LookupRuntimeFunc("msanread")
   149  	ir.Syms.Msanwrite = typecheck.LookupRuntimeFunc("msanwrite")
   150  	ir.Syms.Msanmove = typecheck.LookupRuntimeFunc("msanmove")
   151  	ir.Syms.Asanread = typecheck.LookupRuntimeFunc("asanread")
   152  	ir.Syms.Asanwrite = typecheck.LookupRuntimeFunc("asanwrite")
   153  	ir.Syms.Newobject = typecheck.LookupRuntimeFunc("newobject")
   154  	ir.Syms.Newproc = typecheck.LookupRuntimeFunc("newproc")
   155  	ir.Syms.PanicBounds = typecheck.LookupRuntimeFunc("panicBounds")
   156  	ir.Syms.PanicExtend = typecheck.LookupRuntimeFunc("panicExtend")
   157  	ir.Syms.Panicdivide = typecheck.LookupRuntimeFunc("panicdivide")
   158  	ir.Syms.PanicdottypeE = typecheck.LookupRuntimeFunc("panicdottypeE")
   159  	ir.Syms.PanicdottypeI = typecheck.LookupRuntimeFunc("panicdottypeI")
   160  	ir.Syms.Panicnildottype = typecheck.LookupRuntimeFunc("panicnildottype")
   161  	ir.Syms.Panicoverflow = typecheck.LookupRuntimeFunc("panicoverflow")
   162  	ir.Syms.Panicshift = typecheck.LookupRuntimeFunc("panicshift")
   163  	ir.Syms.PanicSimdImm = typecheck.LookupRuntimeFunc("panicSimdImm")
   164  	ir.Syms.Racefuncenter = typecheck.LookupRuntimeFunc("racefuncenter")
   165  	ir.Syms.Racefuncexit = typecheck.LookupRuntimeFunc("racefuncexit")
   166  	ir.Syms.Raceread = typecheck.LookupRuntimeFunc("raceread")
   167  	ir.Syms.Racereadrange = typecheck.LookupRuntimeFunc("racereadrange")
   168  	ir.Syms.Racewrite = typecheck.LookupRuntimeFunc("racewrite")
   169  	ir.Syms.Racewriterange = typecheck.LookupRuntimeFunc("racewriterange")
   170  	ir.Syms.TypeAssert = typecheck.LookupRuntimeFunc("typeAssert")
   171  	ir.Syms.WBZero = typecheck.LookupRuntimeFunc("wbZero")
   172  	ir.Syms.WBMove = typecheck.LookupRuntimeFunc("wbMove")
   173  	ir.Syms.X86HasAVX = typecheck.LookupRuntimeVar("x86HasAVX")               // bool
   174  	ir.Syms.X86HasFMA = typecheck.LookupRuntimeVar("x86HasFMA")               // bool
   175  	ir.Syms.X86HasPOPCNT = typecheck.LookupRuntimeVar("x86HasPOPCNT")         // bool
   176  	ir.Syms.X86HasSSE41 = typecheck.LookupRuntimeVar("x86HasSSE41")           // bool
   177  	ir.Syms.ARMHasVFPv4 = typecheck.LookupRuntimeVar("armHasVFPv4")           // bool
   178  	ir.Syms.ARM64HasATOMICS = typecheck.LookupRuntimeVar("arm64HasATOMICS")   // bool
   179  	ir.Syms.Loong64HasLAMCAS = typecheck.LookupRuntimeVar("loong64HasLAMCAS") // bool
   180  	ir.Syms.Loong64HasLAM_BH = typecheck.LookupRuntimeVar("loong64HasLAM_BH") // bool
   181  	ir.Syms.Loong64HasLSX = typecheck.LookupRuntimeVar("loong64HasLSX")       // bool
   182  	ir.Syms.RISCV64HasZbb = typecheck.LookupRuntimeVar("riscv64HasZbb")       // bool
   183  	ir.Syms.Staticuint64s = typecheck.LookupRuntimeVar("staticuint64s")
   184  	ir.Syms.Typedmemmove = typecheck.LookupRuntimeFunc("typedmemmove")
   185  	ir.Syms.Udiv = typecheck.LookupRuntimeVar("udiv")                 // asm func with special ABI
   186  	ir.Syms.WriteBarrier = typecheck.LookupRuntimeVar("writeBarrier") // struct { bool; ... }
   187  	ir.Syms.Zerobase = typecheck.LookupRuntimeVar("zerobase")
   188  	ir.Syms.ZeroVal = typecheck.LookupRuntimeVar("zeroVal")
   189  
   190  	if Arch.LinkArch.Family == sys.Wasm {
   191  		BoundsCheckFunc[ssa.BoundsIndex] = typecheck.LookupRuntimeFunc("goPanicIndex")
   192  		BoundsCheckFunc[ssa.BoundsIndexU] = typecheck.LookupRuntimeFunc("goPanicIndexU")
   193  		BoundsCheckFunc[ssa.BoundsSliceAlen] = typecheck.LookupRuntimeFunc("goPanicSliceAlen")
   194  		BoundsCheckFunc[ssa.BoundsSliceAlenU] = typecheck.LookupRuntimeFunc("goPanicSliceAlenU")
   195  		BoundsCheckFunc[ssa.BoundsSliceAcap] = typecheck.LookupRuntimeFunc("goPanicSliceAcap")
   196  		BoundsCheckFunc[ssa.BoundsSliceAcapU] = typecheck.LookupRuntimeFunc("goPanicSliceAcapU")
   197  		BoundsCheckFunc[ssa.BoundsSliceB] = typecheck.LookupRuntimeFunc("goPanicSliceB")
   198  		BoundsCheckFunc[ssa.BoundsSliceBU] = typecheck.LookupRuntimeFunc("goPanicSliceBU")
   199  		BoundsCheckFunc[ssa.BoundsSlice3Alen] = typecheck.LookupRuntimeFunc("goPanicSlice3Alen")
   200  		BoundsCheckFunc[ssa.BoundsSlice3AlenU] = typecheck.LookupRuntimeFunc("goPanicSlice3AlenU")
   201  		BoundsCheckFunc[ssa.BoundsSlice3Acap] = typecheck.LookupRuntimeFunc("goPanicSlice3Acap")
   202  		BoundsCheckFunc[ssa.BoundsSlice3AcapU] = typecheck.LookupRuntimeFunc("goPanicSlice3AcapU")
   203  		BoundsCheckFunc[ssa.BoundsSlice3B] = typecheck.LookupRuntimeFunc("goPanicSlice3B")
   204  		BoundsCheckFunc[ssa.BoundsSlice3BU] = typecheck.LookupRuntimeFunc("goPanicSlice3BU")
   205  		BoundsCheckFunc[ssa.BoundsSlice3C] = typecheck.LookupRuntimeFunc("goPanicSlice3C")
   206  		BoundsCheckFunc[ssa.BoundsSlice3CU] = typecheck.LookupRuntimeFunc("goPanicSlice3CU")
   207  		BoundsCheckFunc[ssa.BoundsConvert] = typecheck.LookupRuntimeFunc("goPanicSliceConvert")
   208  	}
   209  
   210  	// Wasm (all asm funcs with special ABIs)
   211  	ir.Syms.WasmDiv = typecheck.LookupRuntimeVar("wasmDiv")
   212  	ir.Syms.WasmTruncS = typecheck.LookupRuntimeVar("wasmTruncS")
   213  	ir.Syms.WasmTruncU = typecheck.LookupRuntimeVar("wasmTruncU")
   214  	ir.Syms.SigPanic = typecheck.LookupRuntimeFunc("sigpanic")
   215  }
   216  
   217  func InitTables() {
   218  	initIntrinsics(nil)
   219  }
   220  
   221  // AbiForBodylessFuncStackMap returns the ABI for a bodyless function's stack map.
   222  // This is not necessarily the ABI used to call it.
   223  // Currently (1.17 dev) such a stack map is always ABI0;
   224  // any ABI wrapper that is present is nosplit, hence a precise
   225  // stack map is not needed there (the parameters survive only long
   226  // enough to call the wrapped assembly function).
   227  // This always returns a freshly copied ABI.
   228  func AbiForBodylessFuncStackMap(fn *ir.Func) *abi.ABIConfig {
   229  	return ssaConfig.ABI0.Copy() // No idea what races will result, be safe
   230  }
   231  
   232  // abiForFunc implements ABI policy for a function, but does not return a copy of the ABI.
   233  // Passing a nil function returns the default ABI based on experiment configuration.
   234  func abiForFunc(fn *ir.Func, abi0, abi1 *abi.ABIConfig) *abi.ABIConfig {
   235  	if buildcfg.Experiment.RegabiArgs {
   236  		// Select the ABI based on the function's defining ABI.
   237  		if fn == nil {
   238  			return abi1
   239  		}
   240  		switch fn.ABI {
   241  		case obj.ABI0:
   242  			return abi0
   243  		case obj.ABIInternal:
   244  			// TODO(austin): Clean up the nomenclature here.
   245  			// It's not clear that "abi1" is ABIInternal.
   246  			return abi1
   247  		}
   248  		base.Fatalf("function %v has unknown ABI %v", fn, fn.ABI)
   249  		panic("not reachable")
   250  	}
   251  
   252  	a := abi0
   253  	if fn != nil {
   254  		if fn.Pragma&ir.RegisterParams != 0 { // TODO(register args) remove after register abi is working
   255  			a = abi1
   256  		}
   257  	}
   258  	return a
   259  }
   260  
   261  // emitOpenDeferInfo emits FUNCDATA information about the defers in a function
   262  // that is using open-coded defers.  This funcdata is used to determine the active
   263  // defers in a function and execute those defers during panic processing.
   264  //
   265  // The funcdata is all encoded in varints (since values will almost always be less than
   266  // 128, but stack offsets could potentially be up to 2Gbyte). All "locations" (offsets)
   267  // for stack variables are specified as the number of bytes below varp (pointer to the
   268  // top of the local variables) for their starting address. The format is:
   269  //
   270  //   - Offset of the deferBits variable
   271  //   - Offset of the first closure slot (the rest are laid out consecutively).
   272  func (s *state) emitOpenDeferInfo() {
   273  	firstOffset := s.openDefers[0].closureNode.FrameOffset()
   274  
   275  	// Verify that cmpstackvarlt laid out the slots in order.
   276  	for i, r := range s.openDefers {
   277  		have := r.closureNode.FrameOffset()
   278  		want := firstOffset + int64(i)*int64(types.PtrSize)
   279  		if have != want {
   280  			base.FatalfAt(s.curfn.Pos(), "unexpected frame offset for open-coded defer slot #%v: have %v, want %v", i, have, want)
   281  		}
   282  	}
   283  
   284  	x := base.Ctxt.Lookup(s.curfn.LSym.Name + ".opendefer")
   285  	x.Set(obj.AttrContentAddressable, true)
   286  	x.Align = 1
   287  	s.curfn.LSym.Func().OpenCodedDeferInfo = x
   288  
   289  	off := 0
   290  	off = objw.Uvarint(x, off, uint64(-s.deferBitsTemp.FrameOffset()))
   291  	off = objw.Uvarint(x, off, uint64(-firstOffset))
   292  }
   293  
   294  // buildssa builds an SSA function for fn.
   295  // worker indicates which of the backend workers is doing the processing.
   296  func buildssa(fn *ir.Func, worker int, isPgoHot bool) *ssa.Func {
   297  	name := ir.FuncName(fn)
   298  
   299  	abiSelf := abiForFunc(fn, ssaConfig.ABI0, ssaConfig.ABI1)
   300  
   301  	printssa := false
   302  	// match either a simple name e.g. "(*Reader).Reset", package.name e.g. "compress/gzip.(*Reader).Reset", or subpackage name "gzip.(*Reader).Reset"
   303  	// optionally allows an ABI suffix specification in the GOSSAHASH, e.g. "(*Reader).Reset<0>" etc
   304  	if strings.Contains(ssaDump, name) { // in all the cases the function name is entirely contained within the GOSSAFUNC string.
   305  		nameOptABI := name
   306  		if l := len(ssaDump); l > 1 && ssaDump[l-2] == ',' { // ABI specification
   307  			nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   308  		} else if strings.HasSuffix(ssaDump, ">") { // if they use the linker syntax instead....
   309  			l := len(ssaDump)
   310  			if l >= 3 && ssaDump[l-3] == '<' {
   311  				nameOptABI = ssa.FuncNameABI(name, abiSelf.Which())
   312  				ssaDump = ssaDump[:l-3] + "," + ssaDump[l-2:l-1]
   313  			}
   314  		}
   315  		pkgDotName := base.Ctxt.Pkgpath + "." + nameOptABI
   316  		printssa = nameOptABI == ssaDump || // "(*Reader).Reset"
   317  			pkgDotName == ssaDump || // "compress/gzip.(*Reader).Reset"
   318  			strings.HasSuffix(pkgDotName, ssaDump) && strings.HasSuffix(pkgDotName, "/"+ssaDump) // "gzip.(*Reader).Reset"
   319  	}
   320  
   321  	var astBuf *bytes.Buffer
   322  	if printssa {
   323  		astBuf = &bytes.Buffer{}
   324  		ir.FDumpList(astBuf, "buildssa-body", fn.Body)
   325  		if ssaDumpStdout {
   326  			fmt.Println("generating SSA for", name)
   327  			fmt.Print(astBuf.String())
   328  		}
   329  	}
   330  
   331  	var s state
   332  	s.pushLine(fn.Pos())
   333  	defer s.popLine()
   334  
   335  	s.hasdefer = fn.HasDefer()
   336  	if fn.Pragma&ir.CgoUnsafeArgs != 0 {
   337  		s.cgoUnsafeArgs = true
   338  	}
   339  	s.checkPtrEnabled = ir.ShouldCheckPtr(fn, 1)
   340  
   341  	if base.Flag.Cfg.Instrumenting && fn.Pragma&ir.Norace == 0 && !fn.Linksym().ABIWrapper() {
   342  		if !base.Flag.Race || !objabi.LookupPkgSpecial(fn.Sym().Pkg.Path).NoRaceFunc {
   343  			s.instrumentMemory = true
   344  			if base.Flag.Race {
   345  				s.instrumentEnterExit = true
   346  			}
   347  		}
   348  	}
   349  
   350  	fe := ssafn{
   351  		curfn: fn,
   352  		log:   printssa && ssaDumpStdout,
   353  	}
   354  	s.curfn = fn
   355  
   356  	cache := &ssaCaches[worker]
   357  	cache.Reset()
   358  
   359  	s.f = ssaConfig.NewFunc(&fe, cache)
   360  	s.config = ssaConfig
   361  	s.f.Type = fn.Type()
   362  	s.f.Name = name
   363  	s.f.PrintOrHtmlSSA = printssa
   364  	if fn.Pragma&ir.Nosplit != 0 {
   365  		s.f.NoSplit = true
   366  	}
   367  	s.f.ABI0 = ssaConfig.ABI0
   368  	s.f.ABI1 = ssaConfig.ABI1
   369  	s.f.ABIDefault = abiForFunc(nil, ssaConfig.ABI0, ssaConfig.ABI1)
   370  	s.f.ABISelf = abiSelf
   371  
   372  	s.panics = map[funcLine]*ssa.Block{}
   373  	s.softFloat = s.config.SoftFloat
   374  
   375  	// Allocate starting block
   376  	s.f.Entry = s.f.NewBlock(ssa.BlockPlain)
   377  	s.f.Entry.Pos = fn.Pos()
   378  	s.f.IsPgoHot = isPgoHot
   379  
   380  	if printssa {
   381  		ssaDF := ssaDumpFile
   382  		if ssaDir != "" {
   383  			ssaDF = filepath.Join(ssaDir, base.Ctxt.Pkgpath+"."+s.f.NameABI()+".html")
   384  			ssaD := filepath.Dir(ssaDF)
   385  			os.MkdirAll(ssaD, 0755)
   386  		}
   387  		s.f.HTMLWriter = ssa.NewHTMLWriter(ssaDF, s.f, ssaDumpCFG)
   388  		// TODO: generate and print a mapping from nodes to values and blocks
   389  		dumpSourcesColumn(s.f.HTMLWriter, fn)
   390  		s.f.HTMLWriter.WriteAST("AST", astBuf)
   391  	}
   392  
   393  	// Allocate starting values
   394  	s.labels = map[string]*ssaLabel{}
   395  	s.fwdVars = map[ir.Node]*ssa.Value{}
   396  	s.startmem = s.entryNewValue0(ssa.OpInitMem, types.TypeMem)
   397  
   398  	s.hasOpenDefers = base.Flag.N == 0 && s.hasdefer && !s.curfn.OpenCodedDeferDisallowed()
   399  	switch {
   400  	case base.Debug.NoOpenDefer != 0:
   401  		s.hasOpenDefers = false
   402  	case s.hasOpenDefers && (base.Ctxt.Flag_shared || base.Ctxt.Flag_dynlink) && base.Ctxt.Arch.Name == "386":
   403  		// Don't support open-coded defers for 386 ONLY when using shared
   404  		// libraries, because there is extra code (added by rewriteToUseGot())
   405  		// preceding the deferreturn/ret code that we don't track correctly.
   406  		//
   407  		// TODO this restriction can be removed given adjusted offset in computeDeferReturn in cmd/link/internal/ld/pcln.go
   408  		s.hasOpenDefers = false
   409  	}
   410  	if s.hasOpenDefers && s.instrumentEnterExit {
   411  		// Skip doing open defers if we need to instrument function
   412  		// returns for the race detector, since we will not generate that
   413  		// code in the case of the extra deferreturn/ret segment.
   414  		s.hasOpenDefers = false
   415  	}
   416  	if s.hasOpenDefers {
   417  		// Similarly, skip if there are any heap-allocated result
   418  		// parameters that need to be copied back to their stack slots.
   419  		for _, f := range s.curfn.Type().Results() {
   420  			if !f.Nname.(*ir.Name).OnStack() {
   421  				s.hasOpenDefers = false
   422  				break
   423  			}
   424  		}
   425  	}
   426  	if s.hasOpenDefers &&
   427  		s.curfn.NumReturns*s.curfn.NumDefers > 15 {
   428  		// Since we are generating defer calls at every exit for
   429  		// open-coded defers, skip doing open-coded defers if there are
   430  		// too many returns (especially if there are multiple defers).
   431  		// Open-coded defers are most important for improving performance
   432  		// for smaller functions (which don't have many returns).
   433  		s.hasOpenDefers = false
   434  	}
   435  
   436  	s.sp = s.entryNewValue0(ssa.OpSP, types.Types[types.TUINTPTR]) // TODO: use generic pointer type (unsafe.Pointer?) instead
   437  	s.sb = s.entryNewValue0(ssa.OpSB, types.Types[types.TUINTPTR])
   438  
   439  	s.startBlock(s.f.Entry)
   440  	s.vars[memVar] = s.startmem
   441  	if s.hasOpenDefers {
   442  		// Create the deferBits variable and stack slot.  deferBits is a
   443  		// bitmask showing which of the open-coded defers in this function
   444  		// have been activated.
   445  		deferBitsTemp := typecheck.TempAt(src.NoXPos, s.curfn, types.Types[types.TUINT8])
   446  		deferBitsTemp.SetAddrtaken(true)
   447  		s.deferBitsTemp = deferBitsTemp
   448  		// For this value, AuxInt is initialized to zero by default
   449  		startDeferBits := s.entryNewValue0(ssa.OpConst8, types.Types[types.TUINT8])
   450  		s.vars[deferBitsVar] = startDeferBits
   451  		s.deferBitsAddr = s.addr(deferBitsTemp)
   452  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, startDeferBits)
   453  		// Make sure that the deferBits stack slot is kept alive (for use
   454  		// by panics) and stores to deferBits are not eliminated, even if
   455  		// all checking code on deferBits in the function exit can be
   456  		// eliminated, because the defer statements were all
   457  		// unconditional.
   458  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, deferBitsTemp, s.mem(), false)
   459  	}
   460  
   461  	var params *abi.ABIParamResultInfo
   462  	params = s.f.ABISelf.ABIAnalyze(fn.Type(), true)
   463  
   464  	// The backend's stackframe pass prunes away entries from the fn's
   465  	// Dcl list, including PARAMOUT nodes that correspond to output
   466  	// params passed in registers. Walk the Dcl list and capture these
   467  	// nodes to a side list, so that we'll have them available during
   468  	// DWARF-gen later on. See issue 48573 for more details.
   469  	var debugInfo ssa.FuncDebug
   470  	for _, n := range fn.Dcl {
   471  		if n.Class == ir.PPARAMOUT && n.IsOutputParamInRegisters() {
   472  			debugInfo.RegOutputParams = append(debugInfo.RegOutputParams, n)
   473  		}
   474  	}
   475  	fn.DebugInfo = &debugInfo
   476  
   477  	// Generate addresses of local declarations
   478  	s.decladdrs = map[*ir.Name]*ssa.Value{}
   479  	for _, n := range fn.Dcl {
   480  		switch n.Class {
   481  		case ir.PPARAM:
   482  			// Be aware that blank and unnamed input parameters will not appear here, but do appear in the type
   483  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   484  		case ir.PPARAMOUT:
   485  			s.decladdrs[n] = s.entryNewValue2A(ssa.OpLocalAddr, types.NewPtr(n.Type()), n, s.sp, s.startmem)
   486  		case ir.PAUTO:
   487  			// processed at each use, to prevent Addr coming
   488  			// before the decl.
   489  		default:
   490  			s.Fatalf("local variable with class %v unimplemented", n.Class)
   491  		}
   492  	}
   493  
   494  	s.f.OwnAux = ssa.OwnAuxCall(fn.LSym, params)
   495  
   496  	// Populate SSAable arguments.
   497  	for _, n := range fn.Dcl {
   498  		if n.Class == ir.PPARAM {
   499  			if s.canSSA(n) {
   500  				v := s.newValue0A(ssa.OpArg, n.Type(), n)
   501  				s.vars[n] = v
   502  				s.addNamedValue(n, v) // This helps with debugging information, not needed for compilation itself.
   503  			} else { // address was taken AND/OR too large for SSA
   504  				paramAssignment := ssa.ParamAssignmentForArgName(s.f, n)
   505  				if len(paramAssignment.Registers) > 0 {
   506  					if ssa.CanSSA(n.Type()) { // SSA-able type, so address was taken -- receive value in OpArg, DO NOT bind to var, store immediately to memory.
   507  						v := s.newValue0A(ssa.OpArg, n.Type(), n)
   508  						s.store(n.Type(), s.decladdrs[n], v)
   509  					} else { // Too big for SSA.
   510  						// Brute force, and early, do a bunch of stores from registers
   511  						// Note that expand calls knows about this and doesn't trouble itself with larger-than-SSA-able Args in registers.
   512  						s.storeParameterRegsToStack(s.f.ABISelf, paramAssignment, n, s.decladdrs[n], false)
   513  					}
   514  				}
   515  			}
   516  		}
   517  	}
   518  
   519  	// Populate closure variables.
   520  	if fn.Needctxt() {
   521  		clo := s.entryNewValue0(ssa.OpGetClosurePtr, s.f.Config.Types.BytePtr)
   522  		if fn.RangeParent != nil && base.Flag.N != 0 {
   523  			// For a range body closure, keep its closure pointer live on the
   524  			// stack with a special name, so the debugger can look for it and
   525  			// find the parent frame.
   526  			sym := &types.Sym{Name: ".closureptr", Pkg: types.LocalPkg}
   527  			cloSlot := s.curfn.NewLocal(src.NoXPos, sym, s.f.Config.Types.BytePtr)
   528  			cloSlot.SetUsed(true)
   529  			cloSlot.SetEsc(ir.EscNever)
   530  			cloSlot.SetAddrtaken(true)
   531  			s.f.CloSlot = cloSlot
   532  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, cloSlot, s.mem(), false)
   533  			addr := s.addr(cloSlot)
   534  			s.store(s.f.Config.Types.BytePtr, addr, clo)
   535  			// Keep it from being dead-store eliminated.
   536  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, cloSlot, s.mem(), false)
   537  		}
   538  		csiter := typecheck.NewClosureStructIter(fn.ClosureVars)
   539  		for {
   540  			n, typ, offset := csiter.Next()
   541  			if n == nil {
   542  				break
   543  			}
   544  
   545  			ptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(typ), offset, clo)
   546  
   547  			// If n is a small variable captured by value, promote
   548  			// it to PAUTO so it can be converted to SSA.
   549  			//
   550  			// Note: While we never capture a variable by value if
   551  			// the user took its address, we may have generated
   552  			// runtime calls that did (#43701). Since we don't
   553  			// convert Addrtaken variables to SSA anyway, no point
   554  			// in promoting them either.
   555  			if n.Byval() && !n.Addrtaken() && ssa.CanSSA(n.Type()) {
   556  				n.Class = ir.PAUTO
   557  				fn.Dcl = append(fn.Dcl, n)
   558  				s.assign(n, s.load(n.Type(), ptr), false, 0)
   559  				continue
   560  			}
   561  
   562  			if !n.Byval() {
   563  				ptr = s.load(typ, ptr)
   564  			}
   565  			s.setHeapaddr(fn.Pos(), n, ptr)
   566  		}
   567  	}
   568  
   569  	// Convert the AST-based IR to the SSA-based IR
   570  	if s.instrumentEnterExit {
   571  		s.rtcall(ir.Syms.Racefuncenter, true, nil, s.newValue0(ssa.OpGetCallerPC, types.Types[types.TUINTPTR]))
   572  	}
   573  	s.zeroResults()
   574  	s.paramsToHeap()
   575  	s.stmtList(fn.Body)
   576  
   577  	// fallthrough to exit
   578  	if s.curBlock != nil {
   579  		s.pushLine(fn.Endlineno)
   580  		s.exit()
   581  		s.popLine()
   582  	}
   583  
   584  	for _, b := range s.f.Blocks {
   585  		if b.Pos != src.NoXPos {
   586  			s.updateUnsetPredPos(b)
   587  		}
   588  	}
   589  
   590  	s.f.HTMLWriter.WritePhase("before insert phis", "before insert phis")
   591  
   592  	s.insertPhis()
   593  
   594  	// Main call to ssa package to compile function
   595  	ssa.Compile(s.f)
   596  
   597  	fe.AllocFrame(s.f)
   598  
   599  	if len(s.openDefers) != 0 {
   600  		s.emitOpenDeferInfo()
   601  	}
   602  
   603  	// Record incoming parameter spill information for morestack calls emitted in the assembler.
   604  	// This is done here, using all the parameters (used, partially used, and unused) because
   605  	// it mimics the behavior of the former ABI (everything stored) and because it's not 100%
   606  	// clear if naming conventions are respected in autogenerated code.
   607  	// TODO figure out exactly what's unused, don't spill it. Make liveness fine-grained, also.
   608  	for _, p := range params.InParams() {
   609  		typs, offs := p.RegisterTypesAndOffsets()
   610  		if len(offs) < len(typs) {
   611  			s.Fatalf("len(offs)=%d < len(typs)=%d, params=\n%s", len(offs), len(typs), params)
   612  		}
   613  		for i, t := range typs {
   614  			o := offs[i]                // offset within parameter
   615  			fo := p.FrameOffset(params) // offset of parameter in frame
   616  			reg := ssa.ObjRegForAbiReg(p.Registers[i], s.f.Config)
   617  			s.f.RegArgs = append(s.f.RegArgs, ssa.Spill{Reg: reg, Offset: fo + o, Type: t})
   618  		}
   619  	}
   620  
   621  	return s.f
   622  }
   623  
   624  func (s *state) storeParameterRegsToStack(abi *abi.ABIConfig, paramAssignment *abi.ABIParamAssignment, n *ir.Name, addr *ssa.Value, pointersOnly bool) {
   625  	typs, offs := paramAssignment.RegisterTypesAndOffsets()
   626  	for i, t := range typs {
   627  		if pointersOnly && !t.IsPtrShaped() {
   628  			continue
   629  		}
   630  		r := paramAssignment.Registers[i]
   631  		o := offs[i]
   632  		op, reg := ssa.ArgOpAndRegisterFor(r, abi)
   633  		aux := &ssa.AuxNameOffset{Name: n, Offset: o}
   634  		v := s.newValue0I(op, t, reg)
   635  		v.Aux = aux
   636  		p := s.newValue1I(ssa.OpOffPtr, types.NewPtr(t), o, addr)
   637  		s.store(t, p, v)
   638  	}
   639  }
   640  
   641  // zeroResults zeros the return values at the start of the function.
   642  // We need to do this very early in the function.  Defer might stop a
   643  // panic and show the return values as they exist at the time of
   644  // panic.  For precise stacks, the garbage collector assumes results
   645  // are always live, so we need to zero them before any allocations,
   646  // even allocations to move params/results to the heap.
   647  func (s *state) zeroResults() {
   648  	for _, f := range s.curfn.Type().Results() {
   649  		n := f.Nname.(*ir.Name)
   650  		if !n.OnStack() {
   651  			// The local which points to the return value is the
   652  			// thing that needs zeroing. This is already handled
   653  			// by a Needzero annotation in plive.go:(*liveness).epilogue.
   654  			continue
   655  		}
   656  		// Zero the stack location containing f.
   657  		if typ := n.Type(); ssa.CanSSA(typ) {
   658  			s.assign(n, s.zeroVal(typ), false, 0)
   659  		} else {
   660  			if typ.HasPointers() || ssa.IsMergeCandidate(n) {
   661  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
   662  			}
   663  			s.zero(n.Type(), s.decladdrs[n])
   664  		}
   665  	}
   666  }
   667  
   668  // paramsToHeap produces code to allocate memory for heap-escaped parameters
   669  // and to copy non-result parameters' values from the stack.
   670  func (s *state) paramsToHeap() {
   671  	do := func(params []*types.Field) {
   672  		for _, f := range params {
   673  			if f.Nname == nil {
   674  				continue // anonymous or blank parameter
   675  			}
   676  			n := f.Nname.(*ir.Name)
   677  			if ir.IsBlank(n) || n.OnStack() {
   678  				continue
   679  			}
   680  			s.newHeapaddr(n)
   681  			if n.Class == ir.PPARAM {
   682  				s.move(n.Type(), s.expr(n.Heapaddr), s.decladdrs[n])
   683  			}
   684  		}
   685  	}
   686  
   687  	typ := s.curfn.Type()
   688  	do(typ.Recvs())
   689  	do(typ.Params())
   690  	do(typ.Results())
   691  }
   692  
   693  // allocSizeAndAlign returns the size and alignment of t.
   694  // Normally just t.Size() and t.Alignment(), but there
   695  // is a special case to handle 64-bit atomics on 32-bit systems.
   696  func allocSizeAndAlign(t *types.Type) (int64, int64) {
   697  	size, align := t.Size(), t.Alignment()
   698  	if types.PtrSize == 4 && align == 4 && size >= 8 {
   699  		// For 64-bit atomics on 32-bit systems.
   700  		size = types.RoundUp(size, 8)
   701  		align = 8
   702  	}
   703  	return size, align
   704  }
   705  func allocSize(t *types.Type) int64 {
   706  	size, _ := allocSizeAndAlign(t)
   707  	return size
   708  }
   709  func allocAlign(t *types.Type) int64 {
   710  	_, align := allocSizeAndAlign(t)
   711  	return align
   712  }
   713  
   714  // newHeapaddr allocates heap memory for n and sets its heap address.
   715  func (s *state) newHeapaddr(n *ir.Name) {
   716  	size := allocSize(n.Type())
   717  	if n.Type().HasPointers() || size >= maxAggregatedHeapAllocation || size == 0 {
   718  		s.setHeapaddr(n.Pos(), n, s.newObject(n.Type()))
   719  		return
   720  	}
   721  
   722  	// Do we have room together with our pending allocations?
   723  	// If not, flush all the current ones.
   724  	var used int64
   725  	for _, v := range s.pendingHeapAllocations {
   726  		used += allocSize(v.Type.Elem())
   727  	}
   728  	if used+size > maxAggregatedHeapAllocation {
   729  		s.flushPendingHeapAllocations()
   730  	}
   731  
   732  	var allocCall *ssa.Value // (SelectN [0] (call of runtime.newobject))
   733  	if len(s.pendingHeapAllocations) == 0 {
   734  		// Make an allocation, but the type being allocated is just
   735  		// the first pending object. We will come back and update it
   736  		// later if needed.
   737  		allocCall = s.newObjectNonSpecialized(n.Type(), nil)
   738  	} else {
   739  		allocCall = s.pendingHeapAllocations[0].Args[0]
   740  	}
   741  	// v is an offset to the shared allocation. Offsets are dummy 0s for now.
   742  	v := s.newValue1I(ssa.OpOffPtr, n.Type().PtrTo(), 0, allocCall)
   743  
   744  	// Add to list of pending allocations.
   745  	s.pendingHeapAllocations = append(s.pendingHeapAllocations, v)
   746  
   747  	// Finally, record for posterity.
   748  	s.setHeapaddr(n.Pos(), n, v)
   749  }
   750  
   751  func (s *state) flushPendingHeapAllocations() {
   752  	pending := s.pendingHeapAllocations
   753  	if len(pending) == 0 {
   754  		return // nothing to do
   755  	}
   756  	s.pendingHeapAllocations = nil // reset state
   757  	ptr := pending[0].Args[0]      // The SelectN [0] op
   758  	call := ptr.Args[0]            // The runtime.newobject call
   759  
   760  	if len(pending) == 1 {
   761  		// Just a single object, do a standard allocation.
   762  		v := pending[0]
   763  		v.Op = ssa.OpCopy // instead of OffPtr [0]
   764  		return
   765  	}
   766  
   767  	// Sort in decreasing alignment.
   768  	// This way we never have to worry about padding.
   769  	// (Stable not required; just cleaner to keep program order among equal alignments.)
   770  	slices.SortStableFunc(pending, func(x, y *ssa.Value) int {
   771  		return cmp.Compare(allocAlign(y.Type.Elem()), allocAlign(x.Type.Elem()))
   772  	})
   773  
   774  	// Figure out how much data we need allocate.
   775  	var size int64
   776  	for _, v := range pending {
   777  		v.AuxInt = size // Adjust OffPtr to the right value while we are here.
   778  		size += allocSize(v.Type.Elem())
   779  	}
   780  	align := allocAlign(pending[0].Type.Elem())
   781  	size = types.RoundUp(size, align)
   782  
   783  	// Convert newObject call to a mallocgc call.
   784  	args := []*ssa.Value{
   785  		s.constInt(types.Types[types.TUINTPTR], size),
   786  		s.constNil(call.Args[0].Type), // a nil *runtime._type
   787  		s.constBool(true),             // needZero TODO: false is ok?
   788  		call.Args[1],                  // memory
   789  	}
   790  	mallocSym := ir.Syms.MallocGC
   791  	if specialMallocSym := s.specializedMallocSym(size, false); specialMallocSym != nil {
   792  		mallocSym = specialMallocSym
   793  	}
   794  	call.Aux = ssa.StaticAuxCall(mallocSym, s.f.ABIDefault.ABIAnalyzeTypes(
   795  		[]*types.Type{args[0].Type, args[1].Type, args[2].Type},
   796  		[]*types.Type{types.Types[types.TUNSAFEPTR]},
   797  	))
   798  	call.AuxInt = 4 * s.config.PtrSize // arg+results size, uintptr/ptr/bool/ptr
   799  	call.SetArgs4(args[0], args[1], args[2], args[3])
   800  	// TODO: figure out how to pass alignment to runtime
   801  
   802  	call.Type = types.NewTuple(types.Types[types.TUNSAFEPTR], types.TypeMem)
   803  	ptr.Type = types.Types[types.TUNSAFEPTR]
   804  }
   805  
   806  func (s *state) specializedMallocSym(size int64, hasPointers bool) *obj.LSym {
   807  	if !s.sizeSpecializedMallocEnabled() {
   808  		return nil
   809  	}
   810  	ptrSize := s.config.PtrSize
   811  	ptrBits := ptrSize * 8
   812  	minSizeForMallocHeader := ptrSize * ptrBits
   813  	heapBitsInSpan := size <= minSizeForMallocHeader
   814  	if !heapBitsInSpan {
   815  		return nil
   816  	}
   817  	divRoundUp := func(n, a uintptr) uintptr { return (n + a - 1) / a }
   818  	sizeClass := gc.SizeToSizeClass8[divRoundUp(uintptr(size), gc.SmallSizeDiv)]
   819  	if hasPointers {
   820  		return ir.Syms.MallocGCSmallScanNoHeader[sizeClass]
   821  	}
   822  	if size < gc.TinySize {
   823  		return ir.Syms.MallocGCTiny[size]
   824  	}
   825  	return ir.Syms.MallocGCSmallNoScan[sizeClass]
   826  }
   827  
   828  func (s *state) sizeSpecializedMallocEnabled() bool {
   829  	if base.Flag.CompilingRuntime {
   830  		// The compiler forces the values of the asan, msan, and race flags to false if
   831  		// we're compiling the runtime, so we lose the information about whether we're
   832  		// building in asan, msan, or race mode. Because the specialized functions don't
   833  		// work in that mode, just turn if off in that case.
   834  		// TODO(matloob): Save the information about whether the flags were passed in
   835  		// originally so we can turn off size specialized malloc in that case instead
   836  		// using Instrumenting below. Then we can remove this condition.
   837  		return false
   838  	}
   839  
   840  	return buildcfg.Experiment.SizeSpecializedMalloc && !base.Flag.Cfg.Instrumenting
   841  }
   842  
   843  // setHeapaddr allocates a new PAUTO variable to store ptr (which must be non-nil)
   844  // and then sets it as n's heap address.
   845  func (s *state) setHeapaddr(pos src.XPos, n *ir.Name, ptr *ssa.Value) {
   846  	if !ptr.Type.IsPtr() || !types.Identical(n.Type(), ptr.Type.Elem()) {
   847  		base.FatalfAt(n.Pos(), "setHeapaddr %L with type %v", n, ptr.Type)
   848  	}
   849  
   850  	// Declare variable to hold address.
   851  	sym := &types.Sym{Name: "&" + n.Sym().Name, Pkg: types.LocalPkg}
   852  	addr := s.curfn.NewLocal(pos, sym, types.NewPtr(n.Type()))
   853  	addr.SetUsed(true)
   854  	types.CalcSize(addr.Type())
   855  
   856  	if n.Class == ir.PPARAMOUT {
   857  		addr.SetIsOutputParamHeapAddr(true)
   858  	}
   859  
   860  	n.Heapaddr = addr
   861  	s.assign(addr, ptr, false, 0)
   862  }
   863  
   864  // newObject returns an SSA value denoting new(typ).
   865  func (s *state) newObject(typ *types.Type) *ssa.Value {
   866  	if typ.Size() == 0 {
   867  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   868  	}
   869  	rtype := s.reflectType(typ)
   870  	if specialMallocSym := s.specializedMallocSym(typ.Size(), typ.HasPointers()); specialMallocSym != nil {
   871  		return s.rtcall(specialMallocSym, true, []*types.Type{types.NewPtr(typ)},
   872  			s.constInt(types.Types[types.TUINTPTR], typ.Size()),
   873  			rtype,
   874  			s.constBool(true),
   875  		)[0]
   876  	}
   877  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
   878  }
   879  
   880  // newObjectNonSpecialized returns an SSA value denoting new(typ). It does
   881  // not produce size-specialized malloc functions.
   882  func (s *state) newObjectNonSpecialized(typ *types.Type, rtype *ssa.Value) *ssa.Value {
   883  	if typ.Size() == 0 {
   884  		return s.newValue1A(ssa.OpAddr, types.NewPtr(typ), ir.Syms.Zerobase, s.sb)
   885  	}
   886  	if rtype == nil {
   887  		rtype = s.reflectType(typ)
   888  	}
   889  	return s.rtcall(ir.Syms.Newobject, true, []*types.Type{types.NewPtr(typ)}, rtype)[0]
   890  }
   891  
   892  func (s *state) checkPtrAlignment(n *ir.ConvExpr, v *ssa.Value, count *ssa.Value) {
   893  	if !n.Type().IsPtr() {
   894  		s.Fatalf("expected pointer type: %v", n.Type())
   895  	}
   896  	elem, rtypeExpr := n.Type().Elem(), n.ElemRType
   897  	if count != nil {
   898  		if !elem.IsArray() {
   899  			s.Fatalf("expected array type: %v", elem)
   900  		}
   901  		elem, rtypeExpr = elem.Elem(), n.ElemElemRType
   902  	}
   903  	size := elem.Size()
   904  	// Casting from larger type to smaller one is ok, so for smallest type, do nothing.
   905  	if elem.Alignment() == 1 && (size == 0 || size == 1 || count == nil) {
   906  		return
   907  	}
   908  	if count == nil {
   909  		count = s.constInt(types.Types[types.TUINTPTR], 1)
   910  	}
   911  	if count.Type.Size() != s.config.PtrSize {
   912  		s.Fatalf("expected count fit to a uintptr size, have: %d, want: %d", count.Type.Size(), s.config.PtrSize)
   913  	}
   914  	var rtype *ssa.Value
   915  	if rtypeExpr != nil {
   916  		rtype = s.expr(rtypeExpr)
   917  	} else {
   918  		rtype = s.reflectType(elem)
   919  	}
   920  	s.rtcall(ir.Syms.CheckPtrAlignment, true, nil, v, rtype, count)
   921  }
   922  
   923  // reflectType returns an SSA value representing a pointer to typ's
   924  // reflection type descriptor.
   925  func (s *state) reflectType(typ *types.Type) *ssa.Value {
   926  	// TODO(mdempsky): Make this Fatalf under Unified IR; frontend needs
   927  	// to supply RType expressions.
   928  	lsym := reflectdata.TypeLinksym(typ)
   929  	return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(types.Types[types.TUINT8]), lsym, s.sb)
   930  }
   931  
   932  func dumpSourcesColumn(writer *ssa.HTMLWriter, fn *ir.Func) {
   933  	// Read sources of target function fn.
   934  	fname := base.Ctxt.PosTable.Pos(fn.Pos()).Filename()
   935  	targetFn, err := readFuncLines(fname, fn.Pos().Line(), fn.Endlineno.Line())
   936  	if err != nil {
   937  		writer.Logf("cannot read sources for function %v: %v", fn, err)
   938  	}
   939  
   940  	// Read sources of inlined functions.
   941  	var inlFns []*ssa.FuncLines
   942  	for _, fi := range ssaDumpInlined {
   943  		elno := fi.Endlineno
   944  		fname := base.Ctxt.PosTable.Pos(fi.Pos()).Filename()
   945  		fnLines, err := readFuncLines(fname, fi.Pos().Line(), elno.Line())
   946  		if err != nil {
   947  			writer.Logf("cannot read sources for inlined function %v: %v", fi, err)
   948  			continue
   949  		}
   950  		inlFns = append(inlFns, fnLines)
   951  	}
   952  
   953  	slices.SortFunc(inlFns, ssa.ByTopoCmp)
   954  	if targetFn != nil {
   955  		inlFns = append([]*ssa.FuncLines{targetFn}, inlFns...)
   956  	}
   957  
   958  	writer.WriteSources("sources", inlFns)
   959  }
   960  
   961  func readFuncLines(file string, start, end uint) (*ssa.FuncLines, error) {
   962  	f, err := os.Open(os.ExpandEnv(file))
   963  	if err != nil {
   964  		return nil, err
   965  	}
   966  	defer f.Close()
   967  	var lines []string
   968  	ln := uint(1)
   969  	scanner := bufio.NewScanner(f)
   970  	for scanner.Scan() && ln <= end {
   971  		if ln >= start {
   972  			lines = append(lines, scanner.Text())
   973  		}
   974  		ln++
   975  	}
   976  	return &ssa.FuncLines{Filename: file, StartLineno: start, Lines: lines}, nil
   977  }
   978  
   979  // updateUnsetPredPos propagates the earliest-value position information for b
   980  // towards all of b's predecessors that need a position, and recurs on that
   981  // predecessor if its position is updated. B should have a non-empty position.
   982  func (s *state) updateUnsetPredPos(b *ssa.Block) {
   983  	if b.Pos == src.NoXPos {
   984  		s.Fatalf("Block %s should have a position", b)
   985  	}
   986  	bestPos := src.NoXPos
   987  	for _, e := range b.Preds {
   988  		p := e.Block()
   989  		if !p.LackingPos() {
   990  			continue
   991  		}
   992  		if bestPos == src.NoXPos {
   993  			bestPos = b.Pos
   994  			for _, v := range b.Values {
   995  				if v.LackingPos() {
   996  					continue
   997  				}
   998  				if v.Pos != src.NoXPos {
   999  					// Assume values are still in roughly textual order;
  1000  					// TODO: could also seek minimum position?
  1001  					bestPos = v.Pos
  1002  					break
  1003  				}
  1004  			}
  1005  		}
  1006  		p.Pos = bestPos
  1007  		s.updateUnsetPredPos(p) // We do not expect long chains of these, thus recursion is okay.
  1008  	}
  1009  }
  1010  
  1011  // Information about each open-coded defer.
  1012  type openDeferInfo struct {
  1013  	// The node representing the call of the defer
  1014  	n *ir.CallExpr
  1015  	// If defer call is closure call, the address of the argtmp where the
  1016  	// closure is stored.
  1017  	closure *ssa.Value
  1018  	// The node representing the argtmp where the closure is stored - used for
  1019  	// function, method, or interface call, to store a closure that panic
  1020  	// processing can use for this defer.
  1021  	closureNode *ir.Name
  1022  }
  1023  
  1024  type state struct {
  1025  	// configuration (arch) information
  1026  	config *ssa.Config
  1027  
  1028  	// function we're building
  1029  	f *ssa.Func
  1030  
  1031  	// Node for function
  1032  	curfn *ir.Func
  1033  
  1034  	// labels in f
  1035  	labels map[string]*ssaLabel
  1036  
  1037  	// unlabeled break and continue statement tracking
  1038  	breakTo    *ssa.Block // current target for plain break statement
  1039  	continueTo *ssa.Block // current target for plain continue statement
  1040  
  1041  	// current location where we're interpreting the AST
  1042  	curBlock *ssa.Block
  1043  
  1044  	// variable assignments in the current block (map from variable symbol to ssa value)
  1045  	// *Node is the unique identifier (an ONAME Node) for the variable.
  1046  	// TODO: keep a single varnum map, then make all of these maps slices instead?
  1047  	vars map[ir.Node]*ssa.Value
  1048  
  1049  	// fwdVars are variables that are used before they are defined in the current block.
  1050  	// This map exists just to coalesce multiple references into a single FwdRef op.
  1051  	// *Node is the unique identifier (an ONAME Node) for the variable.
  1052  	fwdVars map[ir.Node]*ssa.Value
  1053  
  1054  	// all defined variables at the end of each block. Indexed by block ID.
  1055  	defvars []map[ir.Node]*ssa.Value
  1056  
  1057  	// addresses of PPARAM and PPARAMOUT variables on the stack.
  1058  	decladdrs map[*ir.Name]*ssa.Value
  1059  
  1060  	// starting values. Memory, stack pointer, and globals pointer
  1061  	startmem *ssa.Value
  1062  	sp       *ssa.Value
  1063  	sb       *ssa.Value
  1064  	// value representing address of where deferBits autotmp is stored
  1065  	deferBitsAddr *ssa.Value
  1066  	deferBitsTemp *ir.Name
  1067  
  1068  	// line number stack. The current line number is top of stack
  1069  	line []src.XPos
  1070  	// the last line number processed; it may have been popped
  1071  	lastPos src.XPos
  1072  
  1073  	// list of panic calls by function name and line number.
  1074  	// Used to deduplicate panic calls.
  1075  	panics map[funcLine]*ssa.Block
  1076  
  1077  	cgoUnsafeArgs       bool
  1078  	hasdefer            bool // whether the function contains a defer statement
  1079  	softFloat           bool
  1080  	hasOpenDefers       bool // whether we are doing open-coded defers
  1081  	checkPtrEnabled     bool // whether to insert checkptr instrumentation
  1082  	instrumentEnterExit bool // whether to instrument function enter/exit
  1083  	instrumentMemory    bool // whether to instrument memory operations
  1084  
  1085  	// If doing open-coded defers, list of info about the defer calls in
  1086  	// scanning order. Hence, at exit we should run these defers in reverse
  1087  	// order of this list
  1088  	openDefers []*openDeferInfo
  1089  	// For open-coded defers, this is the beginning and end blocks of the last
  1090  	// defer exit code that we have generated so far. We use these to share
  1091  	// code between exits if the shareDeferExits option (disabled by default)
  1092  	// is on.
  1093  	lastDeferExit       *ssa.Block // Entry block of last defer exit code we generated
  1094  	lastDeferFinalBlock *ssa.Block // Final block of last defer exit code we generated
  1095  	lastDeferCount      int        // Number of defers encountered at that point
  1096  
  1097  	prevCall *ssa.Value // the previous call; use this to tie results to the call op.
  1098  
  1099  	// List of allocations in the current block that are still pending.
  1100  	// They are all (OffPtr (Select0 (runtime call))) and have the correct types,
  1101  	// but the offsets are not set yet, and the type of the runtime call is also not final.
  1102  	pendingHeapAllocations []*ssa.Value
  1103  
  1104  	// First argument of append calls that could be stack allocated.
  1105  	appendTargets map[ir.Node]bool
  1106  
  1107  	// Block starting position, indexed by block id.
  1108  	blockStarts []src.XPos
  1109  
  1110  	// Information for stack allocation. Indexed by the first argument
  1111  	// to an append call. Normally a slice-typed variable, but not always.
  1112  	backingStores map[ir.Node]*backingStoreInfo
  1113  }
  1114  
  1115  type backingStoreInfo struct {
  1116  	// Size of backing store array (in elements)
  1117  	K int64
  1118  	// Stack-allocated backing store variable.
  1119  	store *ir.Name
  1120  	// Dynamic boolean variable marking the fact that we used this backing store.
  1121  	used *ir.Name
  1122  	// Have we used this variable statically yet? This is just a hint
  1123  	// to avoid checking the dynamic variable if the answer is obvious.
  1124  	// (usedStatic == true implies used == true)
  1125  	usedStatic bool
  1126  }
  1127  
  1128  type funcLine struct {
  1129  	f    *obj.LSym
  1130  	base *src.PosBase
  1131  	line uint
  1132  }
  1133  
  1134  type ssaLabel struct {
  1135  	target         *ssa.Block // block identified by this label
  1136  	breakTarget    *ssa.Block // block to break to in control flow node identified by this label
  1137  	continueTarget *ssa.Block // block to continue to in control flow node identified by this label
  1138  }
  1139  
  1140  // label returns the label associated with sym, creating it if necessary.
  1141  func (s *state) label(sym *types.Sym) *ssaLabel {
  1142  	lab := s.labels[sym.Name]
  1143  	if lab == nil {
  1144  		lab = new(ssaLabel)
  1145  		s.labels[sym.Name] = lab
  1146  	}
  1147  	return lab
  1148  }
  1149  
  1150  func (s *state) Logf(msg string, args ...any) { s.f.Logf(msg, args...) }
  1151  func (s *state) Log() bool                    { return s.f.Log() }
  1152  func (s *state) Fatalf(msg string, args ...any) {
  1153  	s.f.Frontend().Fatalf(s.peekPos(), msg, args...)
  1154  }
  1155  func (s *state) Warnl(pos src.XPos, msg string, args ...any) { s.f.Warnl(pos, msg, args...) }
  1156  func (s *state) Debug_checknil() bool                        { return s.f.Frontend().Debug_checknil() }
  1157  
  1158  func ssaMarker(name string) *ir.Name {
  1159  	return ir.NewNameAt(base.Pos, &types.Sym{Name: name}, nil)
  1160  }
  1161  
  1162  var (
  1163  	// marker node for the memory variable
  1164  	memVar = ssaMarker("mem")
  1165  
  1166  	// marker nodes for temporary variables
  1167  	ptrVar       = ssaMarker("ptr")
  1168  	lenVar       = ssaMarker("len")
  1169  	capVar       = ssaMarker("cap")
  1170  	typVar       = ssaMarker("typ")
  1171  	okVar        = ssaMarker("ok")
  1172  	deferBitsVar = ssaMarker("deferBits")
  1173  	hashVar      = ssaMarker("hash")
  1174  )
  1175  
  1176  // startBlock sets the current block we're generating code in to b.
  1177  func (s *state) startBlock(b *ssa.Block) {
  1178  	if s.curBlock != nil {
  1179  		s.Fatalf("starting block %v when block %v has not ended", b, s.curBlock)
  1180  	}
  1181  	s.curBlock = b
  1182  	s.vars = map[ir.Node]*ssa.Value{}
  1183  	clear(s.fwdVars)
  1184  	for len(s.blockStarts) <= int(b.ID) {
  1185  		s.blockStarts = append(s.blockStarts, src.NoXPos)
  1186  	}
  1187  }
  1188  
  1189  // endBlock marks the end of generating code for the current block.
  1190  // Returns the (former) current block. Returns nil if there is no current
  1191  // block, i.e. if no code flows to the current execution point.
  1192  func (s *state) endBlock() *ssa.Block {
  1193  	b := s.curBlock
  1194  	if b == nil {
  1195  		return nil
  1196  	}
  1197  
  1198  	s.flushPendingHeapAllocations()
  1199  
  1200  	for len(s.defvars) <= int(b.ID) {
  1201  		s.defvars = append(s.defvars, nil)
  1202  	}
  1203  	s.defvars[b.ID] = s.vars
  1204  	s.curBlock = nil
  1205  	s.vars = nil
  1206  	if b.LackingPos() {
  1207  		// Empty plain blocks get the line of their successor (handled after all blocks created),
  1208  		// except for increment blocks in For statements (handled in ssa conversion of OFOR),
  1209  		// and for blocks ending in GOTO/BREAK/CONTINUE.
  1210  		b.Pos = src.NoXPos
  1211  	} else {
  1212  		b.Pos = s.lastPos
  1213  		if s.blockStarts[b.ID] == src.NoXPos {
  1214  			s.blockStarts[b.ID] = s.lastPos
  1215  		}
  1216  	}
  1217  	return b
  1218  }
  1219  
  1220  // pushLine pushes a line number on the line number stack.
  1221  func (s *state) pushLine(line src.XPos) {
  1222  	if !line.IsKnown() {
  1223  		// the frontend may emit node with line number missing,
  1224  		// use the parent line number in this case.
  1225  		line = s.peekPos()
  1226  		if base.Flag.K != 0 {
  1227  			base.Warn("buildssa: unknown position (line 0)")
  1228  		}
  1229  	} else {
  1230  		s.lastPos = line
  1231  	}
  1232  	// The first position we see for a new block is its starting position
  1233  	// (the line number for its phis, if any).
  1234  	if b := s.curBlock; b != nil && s.blockStarts[b.ID] == src.NoXPos {
  1235  		s.blockStarts[b.ID] = line
  1236  	}
  1237  
  1238  	s.line = append(s.line, line)
  1239  }
  1240  
  1241  // popLine pops the top of the line number stack.
  1242  func (s *state) popLine() {
  1243  	s.line = s.line[:len(s.line)-1]
  1244  }
  1245  
  1246  // peekPos peeks the top of the line number stack.
  1247  func (s *state) peekPos() src.XPos {
  1248  	return s.line[len(s.line)-1]
  1249  }
  1250  
  1251  // newValue0 adds a new value with no arguments to the current block.
  1252  func (s *state) newValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1253  	return s.curBlock.NewValue0(s.peekPos(), op, t)
  1254  }
  1255  
  1256  // newValue0A adds a new value with no arguments and an aux value to the current block.
  1257  func (s *state) newValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1258  	return s.curBlock.NewValue0A(s.peekPos(), op, t, aux)
  1259  }
  1260  
  1261  // newValue0I adds a new value with no arguments and an auxint value to the current block.
  1262  func (s *state) newValue0I(op ssa.Op, t *types.Type, auxint int64) *ssa.Value {
  1263  	return s.curBlock.NewValue0I(s.peekPos(), op, t, auxint)
  1264  }
  1265  
  1266  // newValue1 adds a new value with one argument to the current block.
  1267  func (s *state) newValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1268  	return s.curBlock.NewValue1(s.peekPos(), op, t, arg)
  1269  }
  1270  
  1271  // newValue1A adds a new value with one argument and an aux value to the current block.
  1272  func (s *state) newValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1273  	return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1274  }
  1275  
  1276  // newValue1Apos adds a new value with one argument and an aux value to the current block.
  1277  // isStmt determines whether the created values may be a statement or not
  1278  // (i.e., false means never, yes means maybe).
  1279  func (s *state) newValue1Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value, isStmt bool) *ssa.Value {
  1280  	if isStmt {
  1281  		return s.curBlock.NewValue1A(s.peekPos(), op, t, aux, arg)
  1282  	}
  1283  	return s.curBlock.NewValue1A(s.peekPos().WithNotStmt(), op, t, aux, arg)
  1284  }
  1285  
  1286  // newValue1I adds a new value with one argument and an auxint value to the current block.
  1287  func (s *state) newValue1I(op ssa.Op, t *types.Type, aux int64, arg *ssa.Value) *ssa.Value {
  1288  	return s.curBlock.NewValue1I(s.peekPos(), op, t, aux, arg)
  1289  }
  1290  
  1291  // newValue2 adds a new value with two arguments to the current block.
  1292  func (s *state) newValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1293  	return s.curBlock.NewValue2(s.peekPos(), op, t, arg0, arg1)
  1294  }
  1295  
  1296  // newValue2A adds a new value with two arguments and an aux value to the current block.
  1297  func (s *state) newValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1298  	return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1299  }
  1300  
  1301  // newValue2Apos adds a new value with two arguments and an aux value to the current block.
  1302  // isStmt determines whether the created values may be a statement or not
  1303  // (i.e., false means never, yes means maybe).
  1304  func (s *state) newValue2Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value, isStmt bool) *ssa.Value {
  1305  	if isStmt {
  1306  		return s.curBlock.NewValue2A(s.peekPos(), op, t, aux, arg0, arg1)
  1307  	}
  1308  	return s.curBlock.NewValue2A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1)
  1309  }
  1310  
  1311  // newValue2I adds a new value with two arguments and an auxint value to the current block.
  1312  func (s *state) newValue2I(op ssa.Op, t *types.Type, aux int64, arg0, arg1 *ssa.Value) *ssa.Value {
  1313  	return s.curBlock.NewValue2I(s.peekPos(), op, t, aux, arg0, arg1)
  1314  }
  1315  
  1316  // newValue3 adds a new value with three arguments to the current block.
  1317  func (s *state) newValue3(op ssa.Op, t *types.Type, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1318  	return s.curBlock.NewValue3(s.peekPos(), op, t, arg0, arg1, arg2)
  1319  }
  1320  
  1321  // newValue3I adds a new value with three arguments and an auxint value to the current block.
  1322  func (s *state) newValue3I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1323  	return s.curBlock.NewValue3I(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1324  }
  1325  
  1326  // newValue3A adds a new value with three arguments and an aux value to the current block.
  1327  func (s *state) newValue3A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value) *ssa.Value {
  1328  	return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1329  }
  1330  
  1331  // newValue3Apos adds a new value with three arguments and an aux value to the current block.
  1332  // isStmt determines whether the created values may be a statement or not
  1333  // (i.e., false means never, yes means maybe).
  1334  func (s *state) newValue3Apos(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2 *ssa.Value, isStmt bool) *ssa.Value {
  1335  	if isStmt {
  1336  		return s.curBlock.NewValue3A(s.peekPos(), op, t, aux, arg0, arg1, arg2)
  1337  	}
  1338  	return s.curBlock.NewValue3A(s.peekPos().WithNotStmt(), op, t, aux, arg0, arg1, arg2)
  1339  }
  1340  
  1341  // newValue4 adds a new value with four arguments to the current block.
  1342  func (s *state) newValue4(op ssa.Op, t *types.Type, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1343  	return s.curBlock.NewValue4(s.peekPos(), op, t, arg0, arg1, arg2, arg3)
  1344  }
  1345  
  1346  // newValue4A adds a new value with four arguments and an aux value to the current block.
  1347  func (s *state) newValue4A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1348  	return s.curBlock.NewValue4A(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1349  }
  1350  
  1351  // newValue4I adds a new value with four arguments and an auxint value to the current block.
  1352  func (s *state) newValue4I(op ssa.Op, t *types.Type, aux int64, arg0, arg1, arg2, arg3 *ssa.Value) *ssa.Value {
  1353  	return s.curBlock.NewValue4I(s.peekPos(), op, t, aux, arg0, arg1, arg2, arg3)
  1354  }
  1355  
  1356  func (s *state) entryBlock() *ssa.Block {
  1357  	b := s.f.Entry
  1358  	if base.Flag.N > 0 && s.curBlock != nil {
  1359  		// If optimizations are off, allocate in current block instead. Since with -N
  1360  		// we're not doing the CSE or tighten passes, putting lots of stuff in the
  1361  		// entry block leads to O(n^2) entries in the live value map during regalloc.
  1362  		// See issue 45897.
  1363  		b = s.curBlock
  1364  	}
  1365  	return b
  1366  }
  1367  
  1368  // entryNewValue0 adds a new value with no arguments to the entry block.
  1369  func (s *state) entryNewValue0(op ssa.Op, t *types.Type) *ssa.Value {
  1370  	return s.entryBlock().NewValue0(src.NoXPos, op, t)
  1371  }
  1372  
  1373  // entryNewValue0A adds a new value with no arguments and an aux value to the entry block.
  1374  func (s *state) entryNewValue0A(op ssa.Op, t *types.Type, aux ssa.Aux) *ssa.Value {
  1375  	return s.entryBlock().NewValue0A(src.NoXPos, op, t, aux)
  1376  }
  1377  
  1378  // entryNewValue1 adds a new value with one argument to the entry block.
  1379  func (s *state) entryNewValue1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1380  	return s.entryBlock().NewValue1(src.NoXPos, op, t, arg)
  1381  }
  1382  
  1383  // entryNewValue1I adds a new value with one argument and an auxint value to the entry block.
  1384  func (s *state) entryNewValue1I(op ssa.Op, t *types.Type, auxint int64, arg *ssa.Value) *ssa.Value {
  1385  	return s.entryBlock().NewValue1I(src.NoXPos, op, t, auxint, arg)
  1386  }
  1387  
  1388  // entryNewValue1A adds a new value with one argument and an aux value to the entry block.
  1389  func (s *state) entryNewValue1A(op ssa.Op, t *types.Type, aux ssa.Aux, arg *ssa.Value) *ssa.Value {
  1390  	return s.entryBlock().NewValue1A(src.NoXPos, op, t, aux, arg)
  1391  }
  1392  
  1393  // entryNewValue2 adds a new value with two arguments to the entry block.
  1394  func (s *state) entryNewValue2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1395  	return s.entryBlock().NewValue2(src.NoXPos, op, t, arg0, arg1)
  1396  }
  1397  
  1398  // entryNewValue2A adds a new value with two arguments and an aux value to the entry block.
  1399  func (s *state) entryNewValue2A(op ssa.Op, t *types.Type, aux ssa.Aux, arg0, arg1 *ssa.Value) *ssa.Value {
  1400  	return s.entryBlock().NewValue2A(src.NoXPos, op, t, aux, arg0, arg1)
  1401  }
  1402  
  1403  // const* routines add a new const value to the entry block.
  1404  func (s *state) constSlice(t *types.Type) *ssa.Value {
  1405  	return s.f.ConstSlice(t)
  1406  }
  1407  func (s *state) constInterface(t *types.Type) *ssa.Value {
  1408  	return s.f.ConstInterface(t)
  1409  }
  1410  func (s *state) constNil(t *types.Type) *ssa.Value { return s.f.ConstNil(t) }
  1411  func (s *state) constEmptyString(t *types.Type) *ssa.Value {
  1412  	return s.f.ConstEmptyString(t)
  1413  }
  1414  func (s *state) constBool(c bool) *ssa.Value {
  1415  	return s.f.ConstBool(types.Types[types.TBOOL], c)
  1416  }
  1417  func (s *state) constInt8(t *types.Type, c int8) *ssa.Value {
  1418  	return s.f.ConstInt8(t, c)
  1419  }
  1420  func (s *state) constInt16(t *types.Type, c int16) *ssa.Value {
  1421  	return s.f.ConstInt16(t, c)
  1422  }
  1423  func (s *state) constInt32(t *types.Type, c int32) *ssa.Value {
  1424  	return s.f.ConstInt32(t, c)
  1425  }
  1426  func (s *state) constInt64(t *types.Type, c int64) *ssa.Value {
  1427  	return s.f.ConstInt64(t, c)
  1428  }
  1429  func (s *state) constFloat32(t *types.Type, c float64) *ssa.Value {
  1430  	return s.f.ConstFloat32(t, c)
  1431  }
  1432  func (s *state) constFloat64(t *types.Type, c float64) *ssa.Value {
  1433  	return s.f.ConstFloat64(t, c)
  1434  }
  1435  func (s *state) constInt(t *types.Type, c int64) *ssa.Value {
  1436  	if s.config.PtrSize == 8 {
  1437  		return s.constInt64(t, c)
  1438  	}
  1439  	if int64(int32(c)) != c {
  1440  		s.Fatalf("integer constant too big %d", c)
  1441  	}
  1442  	return s.constInt32(t, int32(c))
  1443  }
  1444  
  1445  // newValueOrSfCall* are wrappers around newValue*, which may create a call to a
  1446  // soft-float runtime function instead (when emitting soft-float code).
  1447  func (s *state) newValueOrSfCall1(op ssa.Op, t *types.Type, arg *ssa.Value) *ssa.Value {
  1448  	if s.softFloat {
  1449  		if c, ok := s.sfcall(op, arg); ok {
  1450  			return c
  1451  		}
  1452  	}
  1453  	return s.newValue1(op, t, arg)
  1454  }
  1455  func (s *state) newValueOrSfCall2(op ssa.Op, t *types.Type, arg0, arg1 *ssa.Value) *ssa.Value {
  1456  	if s.softFloat {
  1457  		if c, ok := s.sfcall(op, arg0, arg1); ok {
  1458  			return c
  1459  		}
  1460  	}
  1461  	return s.newValue2(op, t, arg0, arg1)
  1462  }
  1463  
  1464  type instrumentKind uint8
  1465  
  1466  const (
  1467  	instrumentRead = iota
  1468  	instrumentWrite
  1469  	instrumentMove
  1470  )
  1471  
  1472  func (s *state) instrument(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1473  	s.instrument2(t, addr, nil, kind)
  1474  }
  1475  
  1476  // instrumentFields instruments a read/write operation on addr.
  1477  // If it is instrumenting for MSAN or ASAN and t is a struct type, it instruments
  1478  // operation for each field, instead of for the whole struct.
  1479  func (s *state) instrumentFields(t *types.Type, addr *ssa.Value, kind instrumentKind) {
  1480  	if !(base.Flag.MSan || base.Flag.ASan) || !isStructNotSIMD(t) {
  1481  		s.instrument(t, addr, kind)
  1482  		return
  1483  	}
  1484  	for _, f := range t.Fields() {
  1485  		if f.Sym.IsBlank() {
  1486  			continue
  1487  		}
  1488  		offptr := s.newValue1I(ssa.OpOffPtr, types.NewPtr(f.Type), f.Offset, addr)
  1489  		s.instrumentFields(f.Type, offptr, kind)
  1490  	}
  1491  }
  1492  
  1493  func (s *state) instrumentMove(t *types.Type, dst, src *ssa.Value) {
  1494  	if base.Flag.MSan {
  1495  		s.instrument2(t, dst, src, instrumentMove)
  1496  	} else {
  1497  		s.instrument(t, src, instrumentRead)
  1498  		s.instrument(t, dst, instrumentWrite)
  1499  	}
  1500  }
  1501  
  1502  func (s *state) instrument2(t *types.Type, addr, addr2 *ssa.Value, kind instrumentKind) {
  1503  	if !s.instrumentMemory {
  1504  		return
  1505  	}
  1506  
  1507  	w := t.Size()
  1508  	if w == 0 {
  1509  		return // can't race on zero-sized things
  1510  	}
  1511  
  1512  	if ssa.IsSanitizerSafeAddr(addr) {
  1513  		return
  1514  	}
  1515  
  1516  	var fn *obj.LSym
  1517  	needWidth := false
  1518  
  1519  	if addr2 != nil && kind != instrumentMove {
  1520  		panic("instrument2: non-nil addr2 for non-move instrumentation")
  1521  	}
  1522  
  1523  	if base.Flag.MSan {
  1524  		switch kind {
  1525  		case instrumentRead:
  1526  			fn = ir.Syms.Msanread
  1527  		case instrumentWrite:
  1528  			fn = ir.Syms.Msanwrite
  1529  		case instrumentMove:
  1530  			fn = ir.Syms.Msanmove
  1531  		default:
  1532  			panic("unreachable")
  1533  		}
  1534  		needWidth = true
  1535  	} else if base.Flag.Race && t.NumComponents(types.CountBlankFields) > 1 {
  1536  		// for composite objects we have to write every address
  1537  		// because a write might happen to any subobject.
  1538  		// composites with only one element don't have subobjects, though.
  1539  		switch kind {
  1540  		case instrumentRead:
  1541  			fn = ir.Syms.Racereadrange
  1542  		case instrumentWrite:
  1543  			fn = ir.Syms.Racewriterange
  1544  		default:
  1545  			panic("unreachable")
  1546  		}
  1547  		needWidth = true
  1548  	} else if base.Flag.Race {
  1549  		// for non-composite objects we can write just the start
  1550  		// address, as any write must write the first byte.
  1551  		switch kind {
  1552  		case instrumentRead:
  1553  			fn = ir.Syms.Raceread
  1554  		case instrumentWrite:
  1555  			fn = ir.Syms.Racewrite
  1556  		default:
  1557  			panic("unreachable")
  1558  		}
  1559  	} else if base.Flag.ASan {
  1560  		switch kind {
  1561  		case instrumentRead:
  1562  			fn = ir.Syms.Asanread
  1563  		case instrumentWrite:
  1564  			fn = ir.Syms.Asanwrite
  1565  		default:
  1566  			panic("unreachable")
  1567  		}
  1568  		needWidth = true
  1569  	} else {
  1570  		panic("unreachable")
  1571  	}
  1572  
  1573  	args := []*ssa.Value{addr}
  1574  	if addr2 != nil {
  1575  		args = append(args, addr2)
  1576  	}
  1577  	if needWidth {
  1578  		args = append(args, s.constInt(types.Types[types.TUINTPTR], w))
  1579  	}
  1580  	s.rtcall(fn, true, nil, args...)
  1581  }
  1582  
  1583  func (s *state) load(t *types.Type, src *ssa.Value) *ssa.Value {
  1584  	s.instrumentFields(t, src, instrumentRead)
  1585  	return s.rawLoad(t, src)
  1586  }
  1587  
  1588  func (s *state) rawLoad(t *types.Type, src *ssa.Value) *ssa.Value {
  1589  	return s.newValue2(ssa.OpLoad, t, src, s.mem())
  1590  }
  1591  
  1592  func (s *state) store(t *types.Type, dst, val *ssa.Value) {
  1593  	s.vars[memVar] = s.newValue3A(ssa.OpStore, types.TypeMem, t, dst, val, s.mem())
  1594  }
  1595  
  1596  func (s *state) zero(t *types.Type, dst *ssa.Value) {
  1597  	s.instrument(t, dst, instrumentWrite)
  1598  	store := s.newValue2I(ssa.OpZero, types.TypeMem, t.Size(), dst, s.mem())
  1599  	store.Aux = t
  1600  	s.vars[memVar] = store
  1601  }
  1602  
  1603  func (s *state) move(t *types.Type, dst, src *ssa.Value) {
  1604  	s.moveWhichMayOverlap(t, dst, src, false)
  1605  }
  1606  func (s *state) moveWhichMayOverlap(t *types.Type, dst, src *ssa.Value, mayOverlap bool) {
  1607  	s.instrumentMove(t, dst, src)
  1608  	if mayOverlap && t.IsArray() && t.NumElem() > 1 && !ssa.IsInlinableMemmove(dst, src, t.Size(), s.f.Config) {
  1609  		// Normally, when moving Go values of type T from one location to another,
  1610  		// we don't need to worry about partial overlaps. The two Ts must either be
  1611  		// in disjoint (nonoverlapping) memory or in exactly the same location.
  1612  		// There are 2 cases where this isn't true:
  1613  		//  1) Using unsafe you can arrange partial overlaps.
  1614  		//  2) Since Go 1.17, you can use a cast from a slice to a ptr-to-array.
  1615  		//     https://go.dev/ref/spec#Conversions_from_slice_to_array_pointer
  1616  		//     This feature can be used to construct partial overlaps of array types.
  1617  		//       var a [3]int
  1618  		//       p := (*[2]int)(a[:])
  1619  		//       q := (*[2]int)(a[1:])
  1620  		//       *p = *q
  1621  		// We don't care about solving 1. Or at least, we haven't historically
  1622  		// and no one has complained.
  1623  		// For 2, we need to ensure that if there might be partial overlap,
  1624  		// then we can't use OpMove; we must use memmove instead.
  1625  		// (memmove handles partial overlap by copying in the correct
  1626  		// direction. OpMove does not.)
  1627  		//
  1628  		// Note that we have to be careful here not to introduce a call when
  1629  		// we're marshaling arguments to a call or unmarshaling results from a call.
  1630  		// Cases where this is happening must pass mayOverlap to false.
  1631  		// (Currently this only happens when unmarshaling results of a call.)
  1632  		if t.HasPointers() {
  1633  			s.rtcall(ir.Syms.Typedmemmove, true, nil, s.reflectType(t), dst, src)
  1634  			// We would have otherwise implemented this move with straightline code,
  1635  			// including a write barrier. Pretend we issue a write barrier here,
  1636  			// so that the write barrier tests work. (Otherwise they'd need to know
  1637  			// the details of IsInlineableMemmove.)
  1638  			s.curfn.SetWBPos(s.peekPos())
  1639  		} else {
  1640  			s.rtcall(ir.Syms.Memmove, true, nil, dst, src, s.constInt(types.Types[types.TUINTPTR], t.Size()))
  1641  		}
  1642  		ssa.LogLargeCopy(s.f.Name, s.peekPos(), t.Size())
  1643  		return
  1644  	}
  1645  	store := s.newValue3I(ssa.OpMove, types.TypeMem, t.Size(), dst, src, s.mem())
  1646  	store.Aux = t
  1647  	s.vars[memVar] = store
  1648  }
  1649  
  1650  // stmtList converts the statement list n to SSA and adds it to s.
  1651  func (s *state) stmtList(l ir.Nodes) {
  1652  	for _, n := range l {
  1653  		s.stmt(n)
  1654  	}
  1655  }
  1656  
  1657  // stmt converts the statement n to SSA and adds it to s.
  1658  func (s *state) stmt(n ir.Node) {
  1659  	s.pushLine(n.Pos())
  1660  	defer s.popLine()
  1661  
  1662  	// If s.curBlock is nil, and n isn't a label (which might have an associated goto somewhere),
  1663  	// then this code is dead. Stop here.
  1664  	if s.curBlock == nil && n.Op() != ir.OLABEL {
  1665  		return
  1666  	}
  1667  
  1668  	s.stmtList(n.Init())
  1669  	switch n.Op() {
  1670  
  1671  	case ir.OBLOCK:
  1672  		n := n.(*ir.BlockStmt)
  1673  		s.stmtList(n.List)
  1674  
  1675  	case ir.OFALL: // no-op
  1676  
  1677  	// Expression statements
  1678  	case ir.OCALLFUNC:
  1679  		n := n.(*ir.CallExpr)
  1680  		if ir.IsIntrinsicCall(n) {
  1681  			s.intrinsicCall(n)
  1682  			return
  1683  		}
  1684  		fallthrough
  1685  
  1686  	case ir.OCALLINTER:
  1687  		n := n.(*ir.CallExpr)
  1688  		s.callResult(n, callNormal)
  1689  		if n.Op() == ir.OCALLFUNC && n.Fun.Op() == ir.ONAME && n.Fun.(*ir.Name).Class == ir.PFUNC {
  1690  			if fn := n.Fun.Sym().Name; base.Flag.CompilingRuntime && fn == "throw" ||
  1691  				n.Fun.Sym().Pkg == ir.Pkgs.Runtime &&
  1692  					(fn == "throwinit" || fn == "gopanic" || fn == "panicwrap" || fn == "block" ||
  1693  						fn == "panicmakeslicelen" || fn == "panicmakeslicecap" || fn == "panicunsafeslicelen" ||
  1694  						fn == "panicunsafeslicenilptr" || fn == "panicunsafestringlen" || fn == "panicunsafestringnilptr" ||
  1695  						fn == "panicrangestate") {
  1696  				m := s.mem()
  1697  				b := s.endBlock()
  1698  				b.Kind = ssa.BlockExit
  1699  				b.SetControl(m)
  1700  				// TODO: never rewrite OPANIC to OCALLFUNC in the
  1701  				// first place. Need to wait until all backends
  1702  				// go through SSA.
  1703  			}
  1704  		}
  1705  	case ir.ODEFER:
  1706  		n := n.(*ir.GoDeferStmt)
  1707  		if base.Debug.Defer > 0 {
  1708  			var defertype string
  1709  			if s.hasOpenDefers {
  1710  				defertype = "open-coded"
  1711  			} else if n.Esc() == ir.EscNever {
  1712  				defertype = "stack-allocated"
  1713  			} else {
  1714  				defertype = "heap-allocated"
  1715  			}
  1716  			base.WarnfAt(n.Pos(), "%s defer", defertype)
  1717  		}
  1718  		if s.hasOpenDefers {
  1719  			s.openDeferRecord(n.Call.(*ir.CallExpr))
  1720  		} else {
  1721  			d := callDefer
  1722  			if n.Esc() == ir.EscNever && n.DeferAt == nil {
  1723  				d = callDeferStack
  1724  			}
  1725  			s.call(n.Call.(*ir.CallExpr), d, false, n.DeferAt)
  1726  		}
  1727  	case ir.OGO:
  1728  		n := n.(*ir.GoDeferStmt)
  1729  		s.callResult(n.Call.(*ir.CallExpr), callGo)
  1730  
  1731  	case ir.OAS2DOTTYPE:
  1732  		n := n.(*ir.AssignListStmt)
  1733  		var res, resok *ssa.Value
  1734  		if n.Rhs[0].Op() == ir.ODOTTYPE2 {
  1735  			res, resok = s.dottype(n.Rhs[0].(*ir.TypeAssertExpr), true)
  1736  		} else {
  1737  			res, resok = s.dynamicDottype(n.Rhs[0].(*ir.DynamicTypeAssertExpr), true)
  1738  		}
  1739  		deref := false
  1740  		if !ssa.CanSSA(n.Rhs[0].Type()) {
  1741  			if res.Op != ssa.OpLoad {
  1742  				s.Fatalf("dottype of non-load")
  1743  			}
  1744  			mem := s.mem()
  1745  			if res.Args[1] != mem {
  1746  				s.Fatalf("memory no longer live from 2-result dottype load")
  1747  			}
  1748  			deref = true
  1749  			res = res.Args[0]
  1750  		}
  1751  		s.assign(n.Lhs[0], res, deref, 0)
  1752  		s.assign(n.Lhs[1], resok, false, 0)
  1753  		return
  1754  
  1755  	case ir.OAS2FUNC:
  1756  		// We come here only when it is an intrinsic call returning two values.
  1757  		n := n.(*ir.AssignListStmt)
  1758  		call := n.Rhs[0].(*ir.CallExpr)
  1759  		if !ir.IsIntrinsicCall(call) {
  1760  			s.Fatalf("non-intrinsic AS2FUNC not expanded %v", call)
  1761  		}
  1762  		v := s.intrinsicCall(call)
  1763  		v1 := s.newValue1(ssa.OpSelect0, n.Lhs[0].Type(), v)
  1764  		v2 := s.newValue1(ssa.OpSelect1, n.Lhs[1].Type(), v)
  1765  		s.assign(n.Lhs[0], v1, false, 0)
  1766  		s.assign(n.Lhs[1], v2, false, 0)
  1767  		return
  1768  
  1769  	case ir.ODCL:
  1770  		n := n.(*ir.Decl)
  1771  		if v := n.X; v.Esc() == ir.EscHeap {
  1772  			s.newHeapaddr(v)
  1773  		}
  1774  
  1775  	case ir.OLABEL:
  1776  		n := n.(*ir.LabelStmt)
  1777  		sym := n.Label
  1778  		if sym.IsBlank() {
  1779  			// Nothing to do because the label isn't targetable. See issue 52278.
  1780  			break
  1781  		}
  1782  		lab := s.label(sym)
  1783  
  1784  		// The label might already have a target block via a goto.
  1785  		if lab.target == nil {
  1786  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1787  		}
  1788  
  1789  		// Go to that label.
  1790  		// (We pretend "label:" is preceded by "goto label", unless the predecessor is unreachable.)
  1791  		if s.curBlock != nil {
  1792  			b := s.endBlock()
  1793  			b.AddEdgeTo(lab.target)
  1794  		}
  1795  		s.startBlock(lab.target)
  1796  
  1797  	case ir.OGOTO:
  1798  		n := n.(*ir.BranchStmt)
  1799  		sym := n.Label
  1800  
  1801  		lab := s.label(sym)
  1802  		if lab.target == nil {
  1803  			lab.target = s.f.NewBlock(ssa.BlockPlain)
  1804  		}
  1805  
  1806  		b := s.endBlock()
  1807  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  1808  		b.AddEdgeTo(lab.target)
  1809  
  1810  	case ir.OAS:
  1811  		n := n.(*ir.AssignStmt)
  1812  		if n.X == n.Y && n.X.Op() == ir.ONAME {
  1813  			// An x=x assignment. No point in doing anything
  1814  			// here. In addition, skipping this assignment
  1815  			// prevents generating:
  1816  			//   VARDEF x
  1817  			//   COPY x -> x
  1818  			// which is bad because x is incorrectly considered
  1819  			// dead before the vardef. See issue #14904.
  1820  			return
  1821  		}
  1822  
  1823  		// mayOverlap keeps track of whether the LHS and RHS might
  1824  		// refer to partially overlapping memory. Partial overlapping can
  1825  		// only happen for arrays, see the comment in moveWhichMayOverlap.
  1826  		//
  1827  		// If both sides of the assignment are not dereferences, then partial
  1828  		// overlap can't happen. Partial overlap can only occur only when the
  1829  		// arrays referenced are strictly smaller parts of the same base array.
  1830  		// If one side of the assignment is a full array, then partial overlap
  1831  		// can't happen. (The arrays are either disjoint or identical.)
  1832  		mayOverlap := n.X.Op() == ir.ODEREF && (n.Y != nil && n.Y.Op() == ir.ODEREF)
  1833  		if n.Y != nil && n.Y.Op() == ir.ODEREF {
  1834  			p := n.Y.(*ir.StarExpr).X
  1835  			for p.Op() == ir.OCONVNOP {
  1836  				p = p.(*ir.ConvExpr).X
  1837  			}
  1838  			if p.Op() == ir.OSPTR && p.(*ir.UnaryExpr).X.Type().IsString() {
  1839  				// Pointer fields of strings point to unmodifiable memory.
  1840  				// That memory can't overlap with the memory being written.
  1841  				mayOverlap = false
  1842  			}
  1843  		}
  1844  
  1845  		// Evaluate RHS.
  1846  		rhs := n.Y
  1847  		if rhs != nil {
  1848  			switch rhs.Op() {
  1849  			case ir.OSTRUCTLIT, ir.OARRAYLIT, ir.OSLICELIT:
  1850  				// All literals with nonzero fields have already been
  1851  				// rewritten during walk. Any that remain are just T{}
  1852  				// or equivalents. Use the zero value.
  1853  				if !ir.IsZero(rhs) {
  1854  					s.Fatalf("literal with nonzero value in SSA: %v", rhs)
  1855  				}
  1856  				rhs = nil
  1857  			case ir.OAPPEND:
  1858  				rhs := rhs.(*ir.CallExpr)
  1859  				// Check whether we're writing the result of an append back to the same slice.
  1860  				// If so, we handle it specially to avoid write barriers on the fast
  1861  				// (non-growth) path.
  1862  				if !ir.SameSafeExpr(n.X, rhs.Args[0]) || base.Flag.N != 0 {
  1863  					break
  1864  				}
  1865  				// If the slice can be SSA'd, it'll be on the stack,
  1866  				// so there will be no write barriers,
  1867  				// so there's no need to attempt to prevent them.
  1868  				if s.canSSA(n.X) {
  1869  					if base.Debug.Append > 0 { // replicating old diagnostic message
  1870  						base.WarnfAt(n.Pos(), "append: len-only update (in local slice)")
  1871  					}
  1872  					break
  1873  				}
  1874  				if base.Debug.Append > 0 {
  1875  					base.WarnfAt(n.Pos(), "append: len-only update")
  1876  				}
  1877  				s.append(rhs, true)
  1878  				return
  1879  			}
  1880  		}
  1881  
  1882  		if ir.IsBlank(n.X) {
  1883  			// _ = rhs
  1884  			// Just evaluate rhs for side-effects.
  1885  			if rhs != nil {
  1886  				s.expr(rhs)
  1887  			}
  1888  			return
  1889  		}
  1890  
  1891  		var t *types.Type
  1892  		if n.Y != nil {
  1893  			t = n.Y.Type()
  1894  		} else {
  1895  			t = n.X.Type()
  1896  		}
  1897  
  1898  		var r *ssa.Value
  1899  		deref := !ssa.CanSSA(t)
  1900  		if deref {
  1901  			if rhs == nil {
  1902  				r = nil // Signal assign to use OpZero.
  1903  			} else {
  1904  				r = s.addr(rhs)
  1905  			}
  1906  		} else {
  1907  			if rhs == nil {
  1908  				r = s.zeroVal(t)
  1909  			} else {
  1910  				r = s.expr(rhs)
  1911  			}
  1912  		}
  1913  
  1914  		var skip skipMask
  1915  		if rhs != nil && (rhs.Op() == ir.OSLICE || rhs.Op() == ir.OSLICE3 || rhs.Op() == ir.OSLICESTR) && ir.SameSafeExpr(rhs.(*ir.SliceExpr).X, n.X) {
  1916  			// We're assigning a slicing operation back to its source.
  1917  			// Don't write back fields we aren't changing. See issue #14855.
  1918  			rhs := rhs.(*ir.SliceExpr)
  1919  			i, j, k := rhs.Low, rhs.High, rhs.Max
  1920  			if i != nil && (i.Op() == ir.OLITERAL && i.Val().Kind() == constant.Int && ir.Int64Val(i) == 0) {
  1921  				// [0:...] is the same as [:...]
  1922  				i = nil
  1923  			}
  1924  			// TODO: detect defaults for len/cap also.
  1925  			// Currently doesn't really work because (*p)[:len(*p)] appears here as:
  1926  			//    tmp = len(*p)
  1927  			//    (*p)[:tmp]
  1928  			// if j != nil && (j.Op == OLEN && SameSafeExpr(j.Left, n.Left)) {
  1929  			//      j = nil
  1930  			// }
  1931  			// if k != nil && (k.Op == OCAP && SameSafeExpr(k.Left, n.Left)) {
  1932  			//      k = nil
  1933  			// }
  1934  			if i == nil {
  1935  				skip |= skipPtr
  1936  				if j == nil {
  1937  					skip |= skipLen
  1938  				}
  1939  				if k == nil {
  1940  					skip |= skipCap
  1941  				}
  1942  			}
  1943  		}
  1944  
  1945  		s.assignWhichMayOverlap(n.X, r, deref, skip, mayOverlap)
  1946  
  1947  	case ir.OIF:
  1948  		n := n.(*ir.IfStmt)
  1949  		if ir.IsConst(n.Cond, constant.Bool) {
  1950  			s.stmtList(n.Cond.Init())
  1951  			if ir.BoolVal(n.Cond) {
  1952  				s.stmtList(n.Body)
  1953  			} else {
  1954  				s.stmtList(n.Else)
  1955  			}
  1956  			break
  1957  		}
  1958  
  1959  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  1960  		var likely int8
  1961  		if n.Likely {
  1962  			likely = 1
  1963  		}
  1964  		var bThen *ssa.Block
  1965  		if len(n.Body) != 0 {
  1966  			bThen = s.f.NewBlock(ssa.BlockPlain)
  1967  		} else {
  1968  			bThen = bEnd
  1969  		}
  1970  		var bElse *ssa.Block
  1971  		if len(n.Else) != 0 {
  1972  			bElse = s.f.NewBlock(ssa.BlockPlain)
  1973  		} else {
  1974  			bElse = bEnd
  1975  		}
  1976  		s.condBranch(n.Cond, bThen, bElse, likely)
  1977  
  1978  		if len(n.Body) != 0 {
  1979  			s.startBlock(bThen)
  1980  			s.stmtList(n.Body)
  1981  			if b := s.endBlock(); b != nil {
  1982  				b.AddEdgeTo(bEnd)
  1983  			}
  1984  		}
  1985  		if len(n.Else) != 0 {
  1986  			s.startBlock(bElse)
  1987  			s.stmtList(n.Else)
  1988  			if b := s.endBlock(); b != nil {
  1989  				b.AddEdgeTo(bEnd)
  1990  			}
  1991  		}
  1992  		s.startBlock(bEnd)
  1993  
  1994  	case ir.ORETURN:
  1995  		n := n.(*ir.ReturnStmt)
  1996  		s.stmtList(n.Results)
  1997  		b := s.exit()
  1998  		b.Pos = s.lastPos.WithIsStmt()
  1999  
  2000  	case ir.OTAILCALL:
  2001  		n := n.(*ir.TailCallStmt)
  2002  		s.callResult(n.Call, callTail)
  2003  		call := s.mem()
  2004  		b := s.endBlock()
  2005  		b.Kind = ssa.BlockRetJmp // could use BlockExit. BlockRetJmp is mostly for clarity.
  2006  		b.SetControl(call)
  2007  
  2008  	case ir.OCONTINUE, ir.OBREAK:
  2009  		n := n.(*ir.BranchStmt)
  2010  		var to *ssa.Block
  2011  		if n.Label == nil {
  2012  			// plain break/continue
  2013  			switch n.Op() {
  2014  			case ir.OCONTINUE:
  2015  				to = s.continueTo
  2016  			case ir.OBREAK:
  2017  				to = s.breakTo
  2018  			}
  2019  		} else {
  2020  			// labeled break/continue; look up the target
  2021  			sym := n.Label
  2022  			lab := s.label(sym)
  2023  			switch n.Op() {
  2024  			case ir.OCONTINUE:
  2025  				to = lab.continueTarget
  2026  			case ir.OBREAK:
  2027  				to = lab.breakTarget
  2028  			}
  2029  		}
  2030  
  2031  		b := s.endBlock()
  2032  		b.Pos = s.lastPos.WithIsStmt() // Do this even if b is an empty block.
  2033  		b.AddEdgeTo(to)
  2034  
  2035  	case ir.OFOR:
  2036  		// OFOR: for Ninit; Left; Right { Nbody }
  2037  		// cond (Left); body (Nbody); incr (Right)
  2038  		n := n.(*ir.ForStmt)
  2039  		base.Assert(!n.DistinctVars) // Should all be rewritten before escape analysis
  2040  		bCond := s.f.NewBlock(ssa.BlockPlain)
  2041  		bBody := s.f.NewBlock(ssa.BlockPlain)
  2042  		bIncr := s.f.NewBlock(ssa.BlockPlain)
  2043  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  2044  
  2045  		// ensure empty for loops have correct position; issue #30167
  2046  		bBody.Pos = n.Pos()
  2047  
  2048  		// first, jump to condition test
  2049  		b := s.endBlock()
  2050  		b.AddEdgeTo(bCond)
  2051  
  2052  		// generate code to test condition
  2053  		s.startBlock(bCond)
  2054  		if n.Cond != nil {
  2055  			s.condBranch(n.Cond, bBody, bEnd, 1)
  2056  		} else {
  2057  			b := s.endBlock()
  2058  			b.Kind = ssa.BlockPlain
  2059  			b.AddEdgeTo(bBody)
  2060  		}
  2061  
  2062  		// set up for continue/break in body
  2063  		prevContinue := s.continueTo
  2064  		prevBreak := s.breakTo
  2065  		s.continueTo = bIncr
  2066  		s.breakTo = bEnd
  2067  		var lab *ssaLabel
  2068  		if sym := n.Label; sym != nil {
  2069  			// labeled for loop
  2070  			lab = s.label(sym)
  2071  			lab.continueTarget = bIncr
  2072  			lab.breakTarget = bEnd
  2073  		}
  2074  
  2075  		// generate body
  2076  		s.startBlock(bBody)
  2077  		s.stmtList(n.Body)
  2078  
  2079  		// tear down continue/break
  2080  		s.continueTo = prevContinue
  2081  		s.breakTo = prevBreak
  2082  		if lab != nil {
  2083  			lab.continueTarget = nil
  2084  			lab.breakTarget = nil
  2085  		}
  2086  
  2087  		// done with body, goto incr
  2088  		if b := s.endBlock(); b != nil {
  2089  			b.AddEdgeTo(bIncr)
  2090  		}
  2091  
  2092  		// generate incr
  2093  		s.startBlock(bIncr)
  2094  		if n.Post != nil {
  2095  			s.stmt(n.Post)
  2096  		}
  2097  		if b := s.endBlock(); b != nil {
  2098  			b.AddEdgeTo(bCond)
  2099  			// It can happen that bIncr ends in a block containing only VARKILL,
  2100  			// and that muddles the debugging experience.
  2101  			if b.Pos == src.NoXPos {
  2102  				b.Pos = bCond.Pos
  2103  			}
  2104  		}
  2105  
  2106  		s.startBlock(bEnd)
  2107  
  2108  	case ir.OSWITCH, ir.OSELECT:
  2109  		// These have been mostly rewritten by the front end into their Nbody fields.
  2110  		// Our main task is to correctly hook up any break statements.
  2111  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  2112  
  2113  		prevBreak := s.breakTo
  2114  		s.breakTo = bEnd
  2115  		var sym *types.Sym
  2116  		var body ir.Nodes
  2117  		if n.Op() == ir.OSWITCH {
  2118  			n := n.(*ir.SwitchStmt)
  2119  			sym = n.Label
  2120  			body = n.Compiled
  2121  		} else {
  2122  			n := n.(*ir.SelectStmt)
  2123  			sym = n.Label
  2124  			body = n.Compiled
  2125  		}
  2126  
  2127  		var lab *ssaLabel
  2128  		if sym != nil {
  2129  			// labeled
  2130  			lab = s.label(sym)
  2131  			lab.breakTarget = bEnd
  2132  		}
  2133  
  2134  		// generate body code
  2135  		s.stmtList(body)
  2136  
  2137  		s.breakTo = prevBreak
  2138  		if lab != nil {
  2139  			lab.breakTarget = nil
  2140  		}
  2141  
  2142  		// walk adds explicit OBREAK nodes to the end of all reachable code paths.
  2143  		// If we still have a current block here, then mark it unreachable.
  2144  		if s.curBlock != nil {
  2145  			m := s.mem()
  2146  			b := s.endBlock()
  2147  			b.Kind = ssa.BlockExit
  2148  			b.SetControl(m)
  2149  		}
  2150  		s.startBlock(bEnd)
  2151  
  2152  	case ir.OJUMPTABLE:
  2153  		n := n.(*ir.JumpTableStmt)
  2154  
  2155  		// Make blocks we'll need.
  2156  		jt := s.f.NewBlock(ssa.BlockJumpTable)
  2157  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  2158  
  2159  		// The only thing that needs evaluating is the index we're looking up.
  2160  		idx := s.expr(n.Idx)
  2161  		unsigned := idx.Type.IsUnsigned()
  2162  
  2163  		// Extend so we can do everything in uintptr arithmetic.
  2164  		t := types.Types[types.TUINTPTR]
  2165  		idx = s.conv(nil, idx, idx.Type, t)
  2166  
  2167  		// The ending condition for the current block decides whether we'll use
  2168  		// the jump table at all.
  2169  		// We check that min <= idx <= max and jump around the jump table
  2170  		// if that test fails.
  2171  		// We implement min <= idx <= max with 0 <= idx-min <= max-min, because
  2172  		// we'll need idx-min anyway as the control value for the jump table.
  2173  		var min, max uint64
  2174  		if unsigned {
  2175  			min, _ = constant.Uint64Val(n.Cases[0])
  2176  			max, _ = constant.Uint64Val(n.Cases[len(n.Cases)-1])
  2177  		} else {
  2178  			mn, _ := constant.Int64Val(n.Cases[0])
  2179  			mx, _ := constant.Int64Val(n.Cases[len(n.Cases)-1])
  2180  			min = uint64(mn)
  2181  			max = uint64(mx)
  2182  		}
  2183  		// Compare idx-min with max-min, to see if we can use the jump table.
  2184  		idx = s.newValue2(s.ssaOp(ir.OSUB, t), t, idx, s.uintptrConstant(min))
  2185  		width := s.uintptrConstant(max - min)
  2186  		cmp := s.newValue2(s.ssaOp(ir.OLE, t), types.Types[types.TBOOL], idx, width)
  2187  		b := s.endBlock()
  2188  		b.Kind = ssa.BlockIf
  2189  		b.SetControl(cmp)
  2190  		b.AddEdgeTo(jt)             // in range - use jump table
  2191  		b.AddEdgeTo(bEnd)           // out of range - no case in the jump table will trigger
  2192  		b.Likely = ssa.BranchLikely // TODO: assumes missing the table entirely is unlikely. True?
  2193  
  2194  		// Build jump table block.
  2195  		s.startBlock(jt)
  2196  		jt.Pos = n.Pos()
  2197  		if base.Flag.Cfg.SpectreIndex {
  2198  			idx = s.newValue2(ssa.OpSpectreSliceIndex, t, idx, width)
  2199  		}
  2200  		jt.SetControl(idx)
  2201  
  2202  		// Figure out where we should go for each index in the table.
  2203  		table := make([]*ssa.Block, max-min+1)
  2204  		for i := range table {
  2205  			table[i] = bEnd // default target
  2206  		}
  2207  		for i := range n.Targets {
  2208  			c := n.Cases[i]
  2209  			lab := s.label(n.Targets[i])
  2210  			if lab.target == nil {
  2211  				lab.target = s.f.NewBlock(ssa.BlockPlain)
  2212  			}
  2213  			var val uint64
  2214  			if unsigned {
  2215  				val, _ = constant.Uint64Val(c)
  2216  			} else {
  2217  				vl, _ := constant.Int64Val(c)
  2218  				val = uint64(vl)
  2219  			}
  2220  			// Overwrite the default target.
  2221  			table[val-min] = lab.target
  2222  		}
  2223  		for _, t := range table {
  2224  			jt.AddEdgeTo(t)
  2225  		}
  2226  		s.endBlock()
  2227  
  2228  		s.startBlock(bEnd)
  2229  
  2230  	case ir.OINTERFACESWITCH:
  2231  		n := n.(*ir.InterfaceSwitchStmt)
  2232  		typs := s.f.Config.Types
  2233  
  2234  		t := s.expr(n.RuntimeType)
  2235  		h := s.expr(n.Hash)
  2236  		d := s.newValue1A(ssa.OpAddr, typs.BytePtr, n.Descriptor, s.sb)
  2237  
  2238  		// Check the cache first.
  2239  		var merge *ssa.Block
  2240  		if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Family) {
  2241  			// Note: we can only use the cache if we have the right atomic load instruction.
  2242  			// Double-check that here.
  2243  			if intrinsics.lookup(Arch.LinkArch.Arch, "internal/runtime/atomic", "Loadp") == nil {
  2244  				s.Fatalf("atomic load not available")
  2245  			}
  2246  			merge = s.f.NewBlock(ssa.BlockPlain)
  2247  			cacheHit := s.f.NewBlock(ssa.BlockPlain)
  2248  			cacheMiss := s.f.NewBlock(ssa.BlockPlain)
  2249  			loopHead := s.f.NewBlock(ssa.BlockPlain)
  2250  			loopBody := s.f.NewBlock(ssa.BlockPlain)
  2251  
  2252  			// Pick right size ops.
  2253  			var mul, and, add, zext ssa.Op
  2254  			if s.config.PtrSize == 4 {
  2255  				mul = ssa.OpMul32
  2256  				and = ssa.OpAnd32
  2257  				add = ssa.OpAdd32
  2258  				zext = ssa.OpCopy
  2259  			} else {
  2260  				mul = ssa.OpMul64
  2261  				and = ssa.OpAnd64
  2262  				add = ssa.OpAdd64
  2263  				zext = ssa.OpZeroExt32to64
  2264  			}
  2265  
  2266  			// Load cache pointer out of descriptor, with an atomic load so
  2267  			// we ensure that we see a fully written cache.
  2268  			atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  2269  			cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  2270  			s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  2271  
  2272  			// Initialize hash variable.
  2273  			s.vars[hashVar] = s.newValue1(zext, typs.Uintptr, h)
  2274  
  2275  			// Load mask from cache.
  2276  			mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  2277  			// Jump to loop head.
  2278  			b := s.endBlock()
  2279  			b.AddEdgeTo(loopHead)
  2280  
  2281  			// At loop head, get pointer to the cache entry.
  2282  			//   e := &cache.Entries[hash&mask]
  2283  			s.startBlock(loopHead)
  2284  			entries := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, s.uintptrConstant(uint64(s.config.PtrSize)))
  2285  			idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  2286  			idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(3*s.config.PtrSize)))
  2287  			e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, entries, idx)
  2288  			//   hash++
  2289  			s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  2290  
  2291  			// Look for a cache hit.
  2292  			//   if e.Typ == t { goto hit }
  2293  			eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  2294  			cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, t, eTyp)
  2295  			b = s.endBlock()
  2296  			b.Kind = ssa.BlockIf
  2297  			b.SetControl(cmp1)
  2298  			b.AddEdgeTo(cacheHit)
  2299  			b.AddEdgeTo(loopBody)
  2300  
  2301  			// Look for an empty entry, the tombstone for this hash table.
  2302  			//   if e.Typ == nil { goto miss }
  2303  			s.startBlock(loopBody)
  2304  			cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  2305  			b = s.endBlock()
  2306  			b.Kind = ssa.BlockIf
  2307  			b.SetControl(cmp2)
  2308  			b.AddEdgeTo(cacheMiss)
  2309  			b.AddEdgeTo(loopHead)
  2310  
  2311  			// On a hit, load the data fields of the cache entry.
  2312  			//   Case = e.Case
  2313  			//   Itab = e.Itab
  2314  			s.startBlock(cacheHit)
  2315  			eCase := s.newValue2(ssa.OpLoad, typs.Int, s.newValue1I(ssa.OpOffPtr, typs.IntPtr, s.config.PtrSize, e), s.mem())
  2316  			eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, 2*s.config.PtrSize, e), s.mem())
  2317  			s.assign(n.Case, eCase, false, 0)
  2318  			s.assign(n.Itab, eItab, false, 0)
  2319  			b = s.endBlock()
  2320  			b.AddEdgeTo(merge)
  2321  
  2322  			// On a miss, call into the runtime to get the answer.
  2323  			s.startBlock(cacheMiss)
  2324  		}
  2325  
  2326  		r := s.rtcall(ir.Syms.InterfaceSwitch, true, []*types.Type{typs.Int, typs.BytePtr}, d, t)
  2327  		s.assign(n.Case, r[0], false, 0)
  2328  		s.assign(n.Itab, r[1], false, 0)
  2329  
  2330  		if merge != nil {
  2331  			// Cache hits merge in here.
  2332  			b := s.endBlock()
  2333  			b.Kind = ssa.BlockPlain
  2334  			b.AddEdgeTo(merge)
  2335  			s.startBlock(merge)
  2336  		}
  2337  
  2338  	case ir.OCHECKNIL:
  2339  		n := n.(*ir.UnaryExpr)
  2340  		p := s.expr(n.X)
  2341  		_ = s.nilCheck(p)
  2342  		// TODO: check that throwing away the nilcheck result is ok.
  2343  
  2344  	case ir.OINLMARK:
  2345  		n := n.(*ir.InlineMarkStmt)
  2346  		s.newValue1I(ssa.OpInlMark, types.TypeVoid, n.Index, s.mem())
  2347  
  2348  	default:
  2349  		s.Fatalf("unhandled stmt %v", n.Op())
  2350  	}
  2351  }
  2352  
  2353  // If true, share as many open-coded defer exits as possible (with the downside of
  2354  // worse line-number information)
  2355  const shareDeferExits = false
  2356  
  2357  // exit processes any code that needs to be generated just before returning.
  2358  // It returns a BlockRet block that ends the control flow. Its control value
  2359  // will be set to the final memory state.
  2360  func (s *state) exit() *ssa.Block {
  2361  	if s.hasdefer {
  2362  		if s.hasOpenDefers {
  2363  			if shareDeferExits && s.lastDeferExit != nil && len(s.openDefers) == s.lastDeferCount {
  2364  				if s.curBlock.Kind != ssa.BlockPlain {
  2365  					panic("Block for an exit should be BlockPlain")
  2366  				}
  2367  				s.curBlock.AddEdgeTo(s.lastDeferExit)
  2368  				s.endBlock()
  2369  				return s.lastDeferFinalBlock
  2370  			}
  2371  			s.openDeferExit()
  2372  		} else {
  2373  			// Shared deferreturn is assigned the "last" position in the function.
  2374  			// The linker picks the first deferreturn call it sees, so this is
  2375  			// the only sensible "shared" place.
  2376  			// To not-share deferreturn, the protocol would need to be changed
  2377  			// so that the call to deferproc-etc would receive the PC offset from
  2378  			// the return PC, and the runtime would need to use that instead of
  2379  			// the deferreturn retrieved from the pcln information.
  2380  			// opendefers would remain a problem, however.
  2381  			s.pushLine(s.curfn.Endlineno)
  2382  			s.rtcall(ir.Syms.Deferreturn, true, nil)
  2383  			s.popLine()
  2384  		}
  2385  	}
  2386  
  2387  	// Do actual return.
  2388  	// These currently turn into self-copies (in many cases).
  2389  	resultFields := s.curfn.Type().Results()
  2390  	results := make([]*ssa.Value, len(resultFields)+1, len(resultFields)+1)
  2391  	// Store SSAable and heap-escaped PPARAMOUT variables back to stack locations.
  2392  	for i, f := range resultFields {
  2393  		n := f.Nname.(*ir.Name)
  2394  		if s.canSSA(n) { // result is in some SSA variable
  2395  			if !n.IsOutputParamInRegisters() && n.Type().HasPointers() {
  2396  				// We are about to store to the result slot.
  2397  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2398  			}
  2399  			results[i] = s.variable(n, n.Type())
  2400  		} else if !n.OnStack() { // result is actually heap allocated
  2401  			// We are about to copy the in-heap result to the result slot.
  2402  			if n.Type().HasPointers() {
  2403  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, n, s.mem())
  2404  			}
  2405  			ha := s.expr(n.Heapaddr)
  2406  			s.instrumentFields(n.Type(), ha, instrumentRead)
  2407  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), ha, s.mem())
  2408  		} else { // result is not SSA-able; not escaped, so not on heap, but too large for SSA.
  2409  			// Before register ABI this ought to be a self-move, home=dest,
  2410  			// With register ABI, it's still a self-move if parameter is on stack (i.e., too big or overflowed)
  2411  			// No VarDef, as the result slot is already holding live value.
  2412  			results[i] = s.newValue2(ssa.OpDereference, n.Type(), s.addr(n), s.mem())
  2413  		}
  2414  	}
  2415  
  2416  	// In -race mode, we need to call racefuncexit.
  2417  	// Note: This has to happen after we load any heap-allocated results,
  2418  	// otherwise races will be attributed to the caller instead.
  2419  	if s.instrumentEnterExit {
  2420  		s.rtcall(ir.Syms.Racefuncexit, true, nil)
  2421  	}
  2422  
  2423  	results[len(results)-1] = s.mem()
  2424  	m := s.newValue0(ssa.OpMakeResult, s.f.OwnAux.LateExpansionResultType())
  2425  	m.AddArgs(results...)
  2426  
  2427  	b := s.endBlock()
  2428  	b.Kind = ssa.BlockRet
  2429  	b.SetControl(m)
  2430  	if s.hasdefer && s.hasOpenDefers {
  2431  		s.lastDeferFinalBlock = b
  2432  	}
  2433  	return b
  2434  }
  2435  
  2436  type opAndType struct {
  2437  	op    ir.Op
  2438  	etype types.Kind
  2439  }
  2440  
  2441  var opToSSA = map[opAndType]ssa.Op{
  2442  	{ir.OADD, types.TINT8}:    ssa.OpAdd8,
  2443  	{ir.OADD, types.TUINT8}:   ssa.OpAdd8,
  2444  	{ir.OADD, types.TINT16}:   ssa.OpAdd16,
  2445  	{ir.OADD, types.TUINT16}:  ssa.OpAdd16,
  2446  	{ir.OADD, types.TINT32}:   ssa.OpAdd32,
  2447  	{ir.OADD, types.TUINT32}:  ssa.OpAdd32,
  2448  	{ir.OADD, types.TINT64}:   ssa.OpAdd64,
  2449  	{ir.OADD, types.TUINT64}:  ssa.OpAdd64,
  2450  	{ir.OADD, types.TFLOAT32}: ssa.OpAdd32F,
  2451  	{ir.OADD, types.TFLOAT64}: ssa.OpAdd64F,
  2452  
  2453  	{ir.OSUB, types.TINT8}:    ssa.OpSub8,
  2454  	{ir.OSUB, types.TUINT8}:   ssa.OpSub8,
  2455  	{ir.OSUB, types.TINT16}:   ssa.OpSub16,
  2456  	{ir.OSUB, types.TUINT16}:  ssa.OpSub16,
  2457  	{ir.OSUB, types.TINT32}:   ssa.OpSub32,
  2458  	{ir.OSUB, types.TUINT32}:  ssa.OpSub32,
  2459  	{ir.OSUB, types.TINT64}:   ssa.OpSub64,
  2460  	{ir.OSUB, types.TUINT64}:  ssa.OpSub64,
  2461  	{ir.OSUB, types.TFLOAT32}: ssa.OpSub32F,
  2462  	{ir.OSUB, types.TFLOAT64}: ssa.OpSub64F,
  2463  
  2464  	{ir.ONOT, types.TBOOL}: ssa.OpNot,
  2465  
  2466  	{ir.ONEG, types.TINT8}:    ssa.OpNeg8,
  2467  	{ir.ONEG, types.TUINT8}:   ssa.OpNeg8,
  2468  	{ir.ONEG, types.TINT16}:   ssa.OpNeg16,
  2469  	{ir.ONEG, types.TUINT16}:  ssa.OpNeg16,
  2470  	{ir.ONEG, types.TINT32}:   ssa.OpNeg32,
  2471  	{ir.ONEG, types.TUINT32}:  ssa.OpNeg32,
  2472  	{ir.ONEG, types.TINT64}:   ssa.OpNeg64,
  2473  	{ir.ONEG, types.TUINT64}:  ssa.OpNeg64,
  2474  	{ir.ONEG, types.TFLOAT32}: ssa.OpNeg32F,
  2475  	{ir.ONEG, types.TFLOAT64}: ssa.OpNeg64F,
  2476  
  2477  	{ir.OBITNOT, types.TINT8}:   ssa.OpCom8,
  2478  	{ir.OBITNOT, types.TUINT8}:  ssa.OpCom8,
  2479  	{ir.OBITNOT, types.TINT16}:  ssa.OpCom16,
  2480  	{ir.OBITNOT, types.TUINT16}: ssa.OpCom16,
  2481  	{ir.OBITNOT, types.TINT32}:  ssa.OpCom32,
  2482  	{ir.OBITNOT, types.TUINT32}: ssa.OpCom32,
  2483  	{ir.OBITNOT, types.TINT64}:  ssa.OpCom64,
  2484  	{ir.OBITNOT, types.TUINT64}: ssa.OpCom64,
  2485  
  2486  	{ir.OIMAG, types.TCOMPLEX64}:  ssa.OpComplexImag,
  2487  	{ir.OIMAG, types.TCOMPLEX128}: ssa.OpComplexImag,
  2488  	{ir.OREAL, types.TCOMPLEX64}:  ssa.OpComplexReal,
  2489  	{ir.OREAL, types.TCOMPLEX128}: ssa.OpComplexReal,
  2490  
  2491  	{ir.OMUL, types.TINT8}:    ssa.OpMul8,
  2492  	{ir.OMUL, types.TUINT8}:   ssa.OpMul8,
  2493  	{ir.OMUL, types.TINT16}:   ssa.OpMul16,
  2494  	{ir.OMUL, types.TUINT16}:  ssa.OpMul16,
  2495  	{ir.OMUL, types.TINT32}:   ssa.OpMul32,
  2496  	{ir.OMUL, types.TUINT32}:  ssa.OpMul32,
  2497  	{ir.OMUL, types.TINT64}:   ssa.OpMul64,
  2498  	{ir.OMUL, types.TUINT64}:  ssa.OpMul64,
  2499  	{ir.OMUL, types.TFLOAT32}: ssa.OpMul32F,
  2500  	{ir.OMUL, types.TFLOAT64}: ssa.OpMul64F,
  2501  
  2502  	{ir.ODIV, types.TFLOAT32}: ssa.OpDiv32F,
  2503  	{ir.ODIV, types.TFLOAT64}: ssa.OpDiv64F,
  2504  
  2505  	{ir.ODIV, types.TINT8}:   ssa.OpDiv8,
  2506  	{ir.ODIV, types.TUINT8}:  ssa.OpDiv8u,
  2507  	{ir.ODIV, types.TINT16}:  ssa.OpDiv16,
  2508  	{ir.ODIV, types.TUINT16}: ssa.OpDiv16u,
  2509  	{ir.ODIV, types.TINT32}:  ssa.OpDiv32,
  2510  	{ir.ODIV, types.TUINT32}: ssa.OpDiv32u,
  2511  	{ir.ODIV, types.TINT64}:  ssa.OpDiv64,
  2512  	{ir.ODIV, types.TUINT64}: ssa.OpDiv64u,
  2513  
  2514  	{ir.OMOD, types.TINT8}:   ssa.OpMod8,
  2515  	{ir.OMOD, types.TUINT8}:  ssa.OpMod8u,
  2516  	{ir.OMOD, types.TINT16}:  ssa.OpMod16,
  2517  	{ir.OMOD, types.TUINT16}: ssa.OpMod16u,
  2518  	{ir.OMOD, types.TINT32}:  ssa.OpMod32,
  2519  	{ir.OMOD, types.TUINT32}: ssa.OpMod32u,
  2520  	{ir.OMOD, types.TINT64}:  ssa.OpMod64,
  2521  	{ir.OMOD, types.TUINT64}: ssa.OpMod64u,
  2522  
  2523  	{ir.OAND, types.TINT8}:   ssa.OpAnd8,
  2524  	{ir.OAND, types.TUINT8}:  ssa.OpAnd8,
  2525  	{ir.OAND, types.TINT16}:  ssa.OpAnd16,
  2526  	{ir.OAND, types.TUINT16}: ssa.OpAnd16,
  2527  	{ir.OAND, types.TINT32}:  ssa.OpAnd32,
  2528  	{ir.OAND, types.TUINT32}: ssa.OpAnd32,
  2529  	{ir.OAND, types.TINT64}:  ssa.OpAnd64,
  2530  	{ir.OAND, types.TUINT64}: ssa.OpAnd64,
  2531  
  2532  	{ir.OOR, types.TINT8}:   ssa.OpOr8,
  2533  	{ir.OOR, types.TUINT8}:  ssa.OpOr8,
  2534  	{ir.OOR, types.TINT16}:  ssa.OpOr16,
  2535  	{ir.OOR, types.TUINT16}: ssa.OpOr16,
  2536  	{ir.OOR, types.TINT32}:  ssa.OpOr32,
  2537  	{ir.OOR, types.TUINT32}: ssa.OpOr32,
  2538  	{ir.OOR, types.TINT64}:  ssa.OpOr64,
  2539  	{ir.OOR, types.TUINT64}: ssa.OpOr64,
  2540  
  2541  	{ir.OXOR, types.TINT8}:   ssa.OpXor8,
  2542  	{ir.OXOR, types.TUINT8}:  ssa.OpXor8,
  2543  	{ir.OXOR, types.TINT16}:  ssa.OpXor16,
  2544  	{ir.OXOR, types.TUINT16}: ssa.OpXor16,
  2545  	{ir.OXOR, types.TINT32}:  ssa.OpXor32,
  2546  	{ir.OXOR, types.TUINT32}: ssa.OpXor32,
  2547  	{ir.OXOR, types.TINT64}:  ssa.OpXor64,
  2548  	{ir.OXOR, types.TUINT64}: ssa.OpXor64,
  2549  
  2550  	{ir.OEQ, types.TBOOL}:      ssa.OpEqB,
  2551  	{ir.OEQ, types.TINT8}:      ssa.OpEq8,
  2552  	{ir.OEQ, types.TUINT8}:     ssa.OpEq8,
  2553  	{ir.OEQ, types.TINT16}:     ssa.OpEq16,
  2554  	{ir.OEQ, types.TUINT16}:    ssa.OpEq16,
  2555  	{ir.OEQ, types.TINT32}:     ssa.OpEq32,
  2556  	{ir.OEQ, types.TUINT32}:    ssa.OpEq32,
  2557  	{ir.OEQ, types.TINT64}:     ssa.OpEq64,
  2558  	{ir.OEQ, types.TUINT64}:    ssa.OpEq64,
  2559  	{ir.OEQ, types.TINTER}:     ssa.OpEqInter,
  2560  	{ir.OEQ, types.TSLICE}:     ssa.OpEqSlice,
  2561  	{ir.OEQ, types.TFUNC}:      ssa.OpEqPtr,
  2562  	{ir.OEQ, types.TMAP}:       ssa.OpEqPtr,
  2563  	{ir.OEQ, types.TCHAN}:      ssa.OpEqPtr,
  2564  	{ir.OEQ, types.TPTR}:       ssa.OpEqPtr,
  2565  	{ir.OEQ, types.TUINTPTR}:   ssa.OpEqPtr,
  2566  	{ir.OEQ, types.TUNSAFEPTR}: ssa.OpEqPtr,
  2567  	{ir.OEQ, types.TFLOAT64}:   ssa.OpEq64F,
  2568  	{ir.OEQ, types.TFLOAT32}:   ssa.OpEq32F,
  2569  
  2570  	{ir.ONE, types.TBOOL}:      ssa.OpNeqB,
  2571  	{ir.ONE, types.TINT8}:      ssa.OpNeq8,
  2572  	{ir.ONE, types.TUINT8}:     ssa.OpNeq8,
  2573  	{ir.ONE, types.TINT16}:     ssa.OpNeq16,
  2574  	{ir.ONE, types.TUINT16}:    ssa.OpNeq16,
  2575  	{ir.ONE, types.TINT32}:     ssa.OpNeq32,
  2576  	{ir.ONE, types.TUINT32}:    ssa.OpNeq32,
  2577  	{ir.ONE, types.TINT64}:     ssa.OpNeq64,
  2578  	{ir.ONE, types.TUINT64}:    ssa.OpNeq64,
  2579  	{ir.ONE, types.TINTER}:     ssa.OpNeqInter,
  2580  	{ir.ONE, types.TSLICE}:     ssa.OpNeqSlice,
  2581  	{ir.ONE, types.TFUNC}:      ssa.OpNeqPtr,
  2582  	{ir.ONE, types.TMAP}:       ssa.OpNeqPtr,
  2583  	{ir.ONE, types.TCHAN}:      ssa.OpNeqPtr,
  2584  	{ir.ONE, types.TPTR}:       ssa.OpNeqPtr,
  2585  	{ir.ONE, types.TUINTPTR}:   ssa.OpNeqPtr,
  2586  	{ir.ONE, types.TUNSAFEPTR}: ssa.OpNeqPtr,
  2587  	{ir.ONE, types.TFLOAT64}:   ssa.OpNeq64F,
  2588  	{ir.ONE, types.TFLOAT32}:   ssa.OpNeq32F,
  2589  
  2590  	{ir.OLT, types.TINT8}:    ssa.OpLess8,
  2591  	{ir.OLT, types.TUINT8}:   ssa.OpLess8U,
  2592  	{ir.OLT, types.TINT16}:   ssa.OpLess16,
  2593  	{ir.OLT, types.TUINT16}:  ssa.OpLess16U,
  2594  	{ir.OLT, types.TINT32}:   ssa.OpLess32,
  2595  	{ir.OLT, types.TUINT32}:  ssa.OpLess32U,
  2596  	{ir.OLT, types.TINT64}:   ssa.OpLess64,
  2597  	{ir.OLT, types.TUINT64}:  ssa.OpLess64U,
  2598  	{ir.OLT, types.TFLOAT64}: ssa.OpLess64F,
  2599  	{ir.OLT, types.TFLOAT32}: ssa.OpLess32F,
  2600  
  2601  	{ir.OLE, types.TINT8}:    ssa.OpLeq8,
  2602  	{ir.OLE, types.TUINT8}:   ssa.OpLeq8U,
  2603  	{ir.OLE, types.TINT16}:   ssa.OpLeq16,
  2604  	{ir.OLE, types.TUINT16}:  ssa.OpLeq16U,
  2605  	{ir.OLE, types.TINT32}:   ssa.OpLeq32,
  2606  	{ir.OLE, types.TUINT32}:  ssa.OpLeq32U,
  2607  	{ir.OLE, types.TINT64}:   ssa.OpLeq64,
  2608  	{ir.OLE, types.TUINT64}:  ssa.OpLeq64U,
  2609  	{ir.OLE, types.TFLOAT64}: ssa.OpLeq64F,
  2610  	{ir.OLE, types.TFLOAT32}: ssa.OpLeq32F,
  2611  }
  2612  
  2613  func (s *state) concreteEtype(t *types.Type) types.Kind {
  2614  	e := t.Kind()
  2615  	switch e {
  2616  	default:
  2617  		return e
  2618  	case types.TINT:
  2619  		if s.config.PtrSize == 8 {
  2620  			return types.TINT64
  2621  		}
  2622  		return types.TINT32
  2623  	case types.TUINT:
  2624  		if s.config.PtrSize == 8 {
  2625  			return types.TUINT64
  2626  		}
  2627  		return types.TUINT32
  2628  	case types.TUINTPTR:
  2629  		if s.config.PtrSize == 8 {
  2630  			return types.TUINT64
  2631  		}
  2632  		return types.TUINT32
  2633  	}
  2634  }
  2635  
  2636  func (s *state) ssaOp(op ir.Op, t *types.Type) ssa.Op {
  2637  	etype := s.concreteEtype(t)
  2638  	x, ok := opToSSA[opAndType{op, etype}]
  2639  	if !ok {
  2640  		s.Fatalf("unhandled binary op %v %s", op, etype)
  2641  	}
  2642  	return x
  2643  }
  2644  
  2645  type opAndTwoTypes struct {
  2646  	op     ir.Op
  2647  	etype1 types.Kind
  2648  	etype2 types.Kind
  2649  }
  2650  
  2651  type twoTypes struct {
  2652  	etype1 types.Kind
  2653  	etype2 types.Kind
  2654  }
  2655  
  2656  type twoOpsAndType struct {
  2657  	op1              ssa.Op
  2658  	op2              ssa.Op
  2659  	intermediateType types.Kind
  2660  }
  2661  
  2662  var fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2663  
  2664  	{types.TINT8, types.TFLOAT32}:  {ssa.OpSignExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2665  	{types.TINT16, types.TFLOAT32}: {ssa.OpSignExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2666  	{types.TINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32to32F, types.TINT32},
  2667  	{types.TINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64to32F, types.TINT64},
  2668  
  2669  	{types.TINT8, types.TFLOAT64}:  {ssa.OpSignExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2670  	{types.TINT16, types.TFLOAT64}: {ssa.OpSignExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2671  	{types.TINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32to64F, types.TINT32},
  2672  	{types.TINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64to64F, types.TINT64},
  2673  
  2674  	{types.TFLOAT32, types.TINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2675  	{types.TFLOAT32, types.TINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2676  	{types.TFLOAT32, types.TINT32}: {ssa.OpCvt32Fto32, ssa.OpCopy, types.TINT32},
  2677  	{types.TFLOAT32, types.TINT64}: {ssa.OpCvt32Fto64, ssa.OpCopy, types.TINT64},
  2678  
  2679  	{types.TFLOAT64, types.TINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2680  	{types.TFLOAT64, types.TINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2681  	{types.TFLOAT64, types.TINT32}: {ssa.OpCvt64Fto32, ssa.OpCopy, types.TINT32},
  2682  	{types.TFLOAT64, types.TINT64}: {ssa.OpCvt64Fto64, ssa.OpCopy, types.TINT64},
  2683  	// unsigned
  2684  	{types.TUINT8, types.TFLOAT32}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to32F, types.TINT32},
  2685  	{types.TUINT16, types.TFLOAT32}: {ssa.OpZeroExt16to32, ssa.OpCvt32to32F, types.TINT32},
  2686  	{types.TUINT32, types.TFLOAT32}: {ssa.OpZeroExt32to64, ssa.OpCvt64to32F, types.TINT64}, // go wide to dodge unsigned
  2687  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto32F, branchy code expansion instead
  2688  
  2689  	{types.TUINT8, types.TFLOAT64}:  {ssa.OpZeroExt8to32, ssa.OpCvt32to64F, types.TINT32},
  2690  	{types.TUINT16, types.TFLOAT64}: {ssa.OpZeroExt16to32, ssa.OpCvt32to64F, types.TINT32},
  2691  	{types.TUINT32, types.TFLOAT64}: {ssa.OpZeroExt32to64, ssa.OpCvt64to64F, types.TINT64}, // go wide to dodge unsigned
  2692  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpInvalid, types.TUINT64},            // Cvt64Uto64F, branchy code expansion instead
  2693  
  2694  	{types.TFLOAT32, types.TUINT8}:  {ssa.OpCvt32Fto32, ssa.OpTrunc32to8, types.TINT32},
  2695  	{types.TFLOAT32, types.TUINT16}: {ssa.OpCvt32Fto32, ssa.OpTrunc32to16, types.TINT32},
  2696  	{types.TFLOAT32, types.TUINT32}: {ssa.OpInvalid, ssa.OpCopy, types.TINT64},  // Cvt64Fto32U, branchy code expansion instead
  2697  	{types.TFLOAT32, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64}, // Cvt32Fto64U, branchy code expansion instead
  2698  
  2699  	{types.TFLOAT64, types.TUINT8}:  {ssa.OpCvt64Fto32, ssa.OpTrunc32to8, types.TINT32},
  2700  	{types.TFLOAT64, types.TUINT16}: {ssa.OpCvt64Fto32, ssa.OpTrunc32to16, types.TINT32},
  2701  	{types.TFLOAT64, types.TUINT32}: {ssa.OpInvalid, ssa.OpCopy, types.TINT64},  // Cvt64Fto32U, branchy code expansion instead
  2702  	{types.TFLOAT64, types.TUINT64}: {ssa.OpInvalid, ssa.OpCopy, types.TUINT64}, // Cvt64Fto64U, branchy code expansion instead
  2703  
  2704  	// float
  2705  	{types.TFLOAT64, types.TFLOAT32}: {ssa.OpCvt64Fto32F, ssa.OpCopy, types.TFLOAT32},
  2706  	{types.TFLOAT64, types.TFLOAT64}: {ssa.OpRound64F, ssa.OpCopy, types.TFLOAT64},
  2707  	{types.TFLOAT32, types.TFLOAT32}: {ssa.OpRound32F, ssa.OpCopy, types.TFLOAT32},
  2708  	{types.TFLOAT32, types.TFLOAT64}: {ssa.OpCvt32Fto64F, ssa.OpCopy, types.TFLOAT64},
  2709  }
  2710  
  2711  // this map is used only for 32-bit arch, and only includes the difference
  2712  // on 32-bit arch, don't use int64<->float conversion for uint32
  2713  var fpConvOpToSSA32 = map[twoTypes]twoOpsAndType{
  2714  	{types.TUINT32, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt32Uto32F, types.TUINT32},
  2715  	{types.TUINT32, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt32Uto64F, types.TUINT32},
  2716  	{types.TFLOAT32, types.TUINT32}: {ssa.OpCvt32Fto32U, ssa.OpCopy, types.TUINT32},
  2717  	{types.TFLOAT64, types.TUINT32}: {ssa.OpCvt64Fto32U, ssa.OpCopy, types.TUINT32},
  2718  }
  2719  
  2720  // uint64<->float conversions, only on machines that have instructions for that
  2721  var uint64fpConvOpToSSA = map[twoTypes]twoOpsAndType{
  2722  	{types.TUINT64, types.TFLOAT32}: {ssa.OpCopy, ssa.OpCvt64Uto32F, types.TUINT64},
  2723  	{types.TUINT64, types.TFLOAT64}: {ssa.OpCopy, ssa.OpCvt64Uto64F, types.TUINT64},
  2724  	{types.TFLOAT32, types.TUINT64}: {ssa.OpCvt32Fto64U, ssa.OpCopy, types.TUINT64},
  2725  	{types.TFLOAT64, types.TUINT64}: {ssa.OpCvt64Fto64U, ssa.OpCopy, types.TUINT64},
  2726  }
  2727  
  2728  var shiftOpToSSA = map[opAndTwoTypes]ssa.Op{
  2729  	{ir.OLSH, types.TINT8, types.TUINT8}:   ssa.OpLsh8x8,
  2730  	{ir.OLSH, types.TUINT8, types.TUINT8}:  ssa.OpLsh8x8,
  2731  	{ir.OLSH, types.TINT8, types.TUINT16}:  ssa.OpLsh8x16,
  2732  	{ir.OLSH, types.TUINT8, types.TUINT16}: ssa.OpLsh8x16,
  2733  	{ir.OLSH, types.TINT8, types.TUINT32}:  ssa.OpLsh8x32,
  2734  	{ir.OLSH, types.TUINT8, types.TUINT32}: ssa.OpLsh8x32,
  2735  	{ir.OLSH, types.TINT8, types.TUINT64}:  ssa.OpLsh8x64,
  2736  	{ir.OLSH, types.TUINT8, types.TUINT64}: ssa.OpLsh8x64,
  2737  
  2738  	{ir.OLSH, types.TINT16, types.TUINT8}:   ssa.OpLsh16x8,
  2739  	{ir.OLSH, types.TUINT16, types.TUINT8}:  ssa.OpLsh16x8,
  2740  	{ir.OLSH, types.TINT16, types.TUINT16}:  ssa.OpLsh16x16,
  2741  	{ir.OLSH, types.TUINT16, types.TUINT16}: ssa.OpLsh16x16,
  2742  	{ir.OLSH, types.TINT16, types.TUINT32}:  ssa.OpLsh16x32,
  2743  	{ir.OLSH, types.TUINT16, types.TUINT32}: ssa.OpLsh16x32,
  2744  	{ir.OLSH, types.TINT16, types.TUINT64}:  ssa.OpLsh16x64,
  2745  	{ir.OLSH, types.TUINT16, types.TUINT64}: ssa.OpLsh16x64,
  2746  
  2747  	{ir.OLSH, types.TINT32, types.TUINT8}:   ssa.OpLsh32x8,
  2748  	{ir.OLSH, types.TUINT32, types.TUINT8}:  ssa.OpLsh32x8,
  2749  	{ir.OLSH, types.TINT32, types.TUINT16}:  ssa.OpLsh32x16,
  2750  	{ir.OLSH, types.TUINT32, types.TUINT16}: ssa.OpLsh32x16,
  2751  	{ir.OLSH, types.TINT32, types.TUINT32}:  ssa.OpLsh32x32,
  2752  	{ir.OLSH, types.TUINT32, types.TUINT32}: ssa.OpLsh32x32,
  2753  	{ir.OLSH, types.TINT32, types.TUINT64}:  ssa.OpLsh32x64,
  2754  	{ir.OLSH, types.TUINT32, types.TUINT64}: ssa.OpLsh32x64,
  2755  
  2756  	{ir.OLSH, types.TINT64, types.TUINT8}:   ssa.OpLsh64x8,
  2757  	{ir.OLSH, types.TUINT64, types.TUINT8}:  ssa.OpLsh64x8,
  2758  	{ir.OLSH, types.TINT64, types.TUINT16}:  ssa.OpLsh64x16,
  2759  	{ir.OLSH, types.TUINT64, types.TUINT16}: ssa.OpLsh64x16,
  2760  	{ir.OLSH, types.TINT64, types.TUINT32}:  ssa.OpLsh64x32,
  2761  	{ir.OLSH, types.TUINT64, types.TUINT32}: ssa.OpLsh64x32,
  2762  	{ir.OLSH, types.TINT64, types.TUINT64}:  ssa.OpLsh64x64,
  2763  	{ir.OLSH, types.TUINT64, types.TUINT64}: ssa.OpLsh64x64,
  2764  
  2765  	{ir.ORSH, types.TINT8, types.TUINT8}:   ssa.OpRsh8x8,
  2766  	{ir.ORSH, types.TUINT8, types.TUINT8}:  ssa.OpRsh8Ux8,
  2767  	{ir.ORSH, types.TINT8, types.TUINT16}:  ssa.OpRsh8x16,
  2768  	{ir.ORSH, types.TUINT8, types.TUINT16}: ssa.OpRsh8Ux16,
  2769  	{ir.ORSH, types.TINT8, types.TUINT32}:  ssa.OpRsh8x32,
  2770  	{ir.ORSH, types.TUINT8, types.TUINT32}: ssa.OpRsh8Ux32,
  2771  	{ir.ORSH, types.TINT8, types.TUINT64}:  ssa.OpRsh8x64,
  2772  	{ir.ORSH, types.TUINT8, types.TUINT64}: ssa.OpRsh8Ux64,
  2773  
  2774  	{ir.ORSH, types.TINT16, types.TUINT8}:   ssa.OpRsh16x8,
  2775  	{ir.ORSH, types.TUINT16, types.TUINT8}:  ssa.OpRsh16Ux8,
  2776  	{ir.ORSH, types.TINT16, types.TUINT16}:  ssa.OpRsh16x16,
  2777  	{ir.ORSH, types.TUINT16, types.TUINT16}: ssa.OpRsh16Ux16,
  2778  	{ir.ORSH, types.TINT16, types.TUINT32}:  ssa.OpRsh16x32,
  2779  	{ir.ORSH, types.TUINT16, types.TUINT32}: ssa.OpRsh16Ux32,
  2780  	{ir.ORSH, types.TINT16, types.TUINT64}:  ssa.OpRsh16x64,
  2781  	{ir.ORSH, types.TUINT16, types.TUINT64}: ssa.OpRsh16Ux64,
  2782  
  2783  	{ir.ORSH, types.TINT32, types.TUINT8}:   ssa.OpRsh32x8,
  2784  	{ir.ORSH, types.TUINT32, types.TUINT8}:  ssa.OpRsh32Ux8,
  2785  	{ir.ORSH, types.TINT32, types.TUINT16}:  ssa.OpRsh32x16,
  2786  	{ir.ORSH, types.TUINT32, types.TUINT16}: ssa.OpRsh32Ux16,
  2787  	{ir.ORSH, types.TINT32, types.TUINT32}:  ssa.OpRsh32x32,
  2788  	{ir.ORSH, types.TUINT32, types.TUINT32}: ssa.OpRsh32Ux32,
  2789  	{ir.ORSH, types.TINT32, types.TUINT64}:  ssa.OpRsh32x64,
  2790  	{ir.ORSH, types.TUINT32, types.TUINT64}: ssa.OpRsh32Ux64,
  2791  
  2792  	{ir.ORSH, types.TINT64, types.TUINT8}:   ssa.OpRsh64x8,
  2793  	{ir.ORSH, types.TUINT64, types.TUINT8}:  ssa.OpRsh64Ux8,
  2794  	{ir.ORSH, types.TINT64, types.TUINT16}:  ssa.OpRsh64x16,
  2795  	{ir.ORSH, types.TUINT64, types.TUINT16}: ssa.OpRsh64Ux16,
  2796  	{ir.ORSH, types.TINT64, types.TUINT32}:  ssa.OpRsh64x32,
  2797  	{ir.ORSH, types.TUINT64, types.TUINT32}: ssa.OpRsh64Ux32,
  2798  	{ir.ORSH, types.TINT64, types.TUINT64}:  ssa.OpRsh64x64,
  2799  	{ir.ORSH, types.TUINT64, types.TUINT64}: ssa.OpRsh64Ux64,
  2800  }
  2801  
  2802  func (s *state) ssaShiftOp(op ir.Op, t *types.Type, u *types.Type) ssa.Op {
  2803  	etype1 := s.concreteEtype(t)
  2804  	etype2 := s.concreteEtype(u)
  2805  	x, ok := shiftOpToSSA[opAndTwoTypes{op, etype1, etype2}]
  2806  	if !ok {
  2807  		s.Fatalf("unhandled shift op %v etype=%s/%s", op, etype1, etype2)
  2808  	}
  2809  	return x
  2810  }
  2811  
  2812  func (s *state) uintptrConstant(v uint64) *ssa.Value {
  2813  	if s.config.PtrSize == 4 {
  2814  		return s.newValue0I(ssa.OpConst32, types.Types[types.TUINTPTR], int64(v))
  2815  	}
  2816  	return s.newValue0I(ssa.OpConst64, types.Types[types.TUINTPTR], int64(v))
  2817  }
  2818  
  2819  func (s *state) conv(n ir.Node, v *ssa.Value, ft, tt *types.Type) *ssa.Value {
  2820  	if ft.IsBoolean() && tt.IsKind(types.TUINT8) {
  2821  		// Bool -> uint8 is generated internally when indexing into runtime.staticbyte.
  2822  		return s.newValue1(ssa.OpCvtBoolToUint8, tt, v)
  2823  	}
  2824  	if ft.IsInteger() && tt.IsInteger() {
  2825  		var op ssa.Op
  2826  		if tt.Size() == ft.Size() {
  2827  			op = ssa.OpCopy
  2828  		} else if tt.Size() < ft.Size() {
  2829  			// truncation
  2830  			switch 10*ft.Size() + tt.Size() {
  2831  			case 21:
  2832  				op = ssa.OpTrunc16to8
  2833  			case 41:
  2834  				op = ssa.OpTrunc32to8
  2835  			case 42:
  2836  				op = ssa.OpTrunc32to16
  2837  			case 81:
  2838  				op = ssa.OpTrunc64to8
  2839  			case 82:
  2840  				op = ssa.OpTrunc64to16
  2841  			case 84:
  2842  				op = ssa.OpTrunc64to32
  2843  			default:
  2844  				s.Fatalf("weird integer truncation %v -> %v", ft, tt)
  2845  			}
  2846  		} else if ft.IsSigned() {
  2847  			// sign extension
  2848  			switch 10*ft.Size() + tt.Size() {
  2849  			case 12:
  2850  				op = ssa.OpSignExt8to16
  2851  			case 14:
  2852  				op = ssa.OpSignExt8to32
  2853  			case 18:
  2854  				op = ssa.OpSignExt8to64
  2855  			case 24:
  2856  				op = ssa.OpSignExt16to32
  2857  			case 28:
  2858  				op = ssa.OpSignExt16to64
  2859  			case 48:
  2860  				op = ssa.OpSignExt32to64
  2861  			default:
  2862  				s.Fatalf("bad integer sign extension %v -> %v", ft, tt)
  2863  			}
  2864  		} else {
  2865  			// zero extension
  2866  			switch 10*ft.Size() + tt.Size() {
  2867  			case 12:
  2868  				op = ssa.OpZeroExt8to16
  2869  			case 14:
  2870  				op = ssa.OpZeroExt8to32
  2871  			case 18:
  2872  				op = ssa.OpZeroExt8to64
  2873  			case 24:
  2874  				op = ssa.OpZeroExt16to32
  2875  			case 28:
  2876  				op = ssa.OpZeroExt16to64
  2877  			case 48:
  2878  				op = ssa.OpZeroExt32to64
  2879  			default:
  2880  				s.Fatalf("weird integer sign extension %v -> %v", ft, tt)
  2881  			}
  2882  		}
  2883  		return s.newValue1(op, tt, v)
  2884  	}
  2885  
  2886  	if ft.IsComplex() && tt.IsComplex() {
  2887  		var op ssa.Op
  2888  		if ft.Size() == tt.Size() {
  2889  			switch ft.Size() {
  2890  			case 8:
  2891  				op = ssa.OpRound32F
  2892  			case 16:
  2893  				op = ssa.OpRound64F
  2894  			default:
  2895  				s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2896  			}
  2897  		} else if ft.Size() == 8 && tt.Size() == 16 {
  2898  			op = ssa.OpCvt32Fto64F
  2899  		} else if ft.Size() == 16 && tt.Size() == 8 {
  2900  			op = ssa.OpCvt64Fto32F
  2901  		} else {
  2902  			s.Fatalf("weird complex conversion %v -> %v", ft, tt)
  2903  		}
  2904  		ftp := types.FloatForComplex(ft)
  2905  		ttp := types.FloatForComplex(tt)
  2906  		return s.newValue2(ssa.OpComplexMake, tt,
  2907  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexReal, ftp, v)),
  2908  			s.newValueOrSfCall1(op, ttp, s.newValue1(ssa.OpComplexImag, ftp, v)))
  2909  	}
  2910  
  2911  	if tt.IsComplex() { // and ft is not complex
  2912  		// Needed for generics support - can't happen in normal Go code.
  2913  		et := types.FloatForComplex(tt)
  2914  		v = s.conv(n, v, ft, et)
  2915  		return s.newValue2(ssa.OpComplexMake, tt, v, s.zeroVal(et))
  2916  	}
  2917  
  2918  	if ft.IsFloat() || tt.IsFloat() {
  2919  		cft, ctt := s.concreteEtype(ft), s.concreteEtype(tt)
  2920  		conv, ok := fpConvOpToSSA[twoTypes{cft, ctt}]
  2921  		// there's a change to a conversion-op table, this restores the old behavior if ConvertHash is false.
  2922  		// use salted hash to distinguish unsigned convert at a Pos from signed convert at a Pos
  2923  		if ctt == types.TUINT32 && ft.IsFloat() && !base.ConvertHash.MatchPosWithInfo(n.Pos(), "U", nil) {
  2924  			// revert to old behavior
  2925  			conv.op1 = ssa.OpCvt64Fto64
  2926  			if cft == types.TFLOAT32 {
  2927  				conv.op1 = ssa.OpCvt32Fto64
  2928  			}
  2929  			conv.op2 = ssa.OpTrunc64to32
  2930  
  2931  		}
  2932  		if s.config.RegSize == 4 && Arch.LinkArch.Family != sys.MIPS && !s.softFloat {
  2933  			if conv1, ok1 := fpConvOpToSSA32[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2934  				conv = conv1
  2935  			}
  2936  		}
  2937  		if Arch.LinkArch.Family == sys.ARM64 || Arch.LinkArch.Family == sys.Wasm || Arch.LinkArch.Family == sys.S390X || s.softFloat {
  2938  			if conv1, ok1 := uint64fpConvOpToSSA[twoTypes{s.concreteEtype(ft), s.concreteEtype(tt)}]; ok1 {
  2939  				conv = conv1
  2940  			}
  2941  		}
  2942  
  2943  		if Arch.LinkArch.Family == sys.MIPS && !s.softFloat {
  2944  			if ft.Size() == 4 && ft.IsInteger() && !ft.IsSigned() {
  2945  				// tt is float32 or float64, and ft is also unsigned
  2946  				if tt.Size() == 4 {
  2947  					return s.uint32Tofloat32(n, v, ft, tt)
  2948  				}
  2949  				if tt.Size() == 8 {
  2950  					return s.uint32Tofloat64(n, v, ft, tt)
  2951  				}
  2952  			} else if tt.Size() == 4 && tt.IsInteger() && !tt.IsSigned() {
  2953  				// ft is float32 or float64, and tt is unsigned integer
  2954  				if ft.Size() == 4 {
  2955  					return s.float32ToUint32(n, v, ft, tt)
  2956  				}
  2957  				if ft.Size() == 8 {
  2958  					return s.float64ToUint32(n, v, ft, tt)
  2959  				}
  2960  			}
  2961  		}
  2962  
  2963  		if !ok {
  2964  			s.Fatalf("weird float conversion %v -> %v", ft, tt)
  2965  		}
  2966  		op1, op2, it := conv.op1, conv.op2, conv.intermediateType
  2967  
  2968  		if op1 != ssa.OpInvalid && op2 != ssa.OpInvalid {
  2969  			// normal case, not tripping over unsigned 64
  2970  			if op1 == ssa.OpCopy {
  2971  				if op2 == ssa.OpCopy {
  2972  					return v
  2973  				}
  2974  				return s.newValueOrSfCall1(op2, tt, v)
  2975  			}
  2976  			if op2 == ssa.OpCopy {
  2977  				return s.newValueOrSfCall1(op1, tt, v)
  2978  			}
  2979  			return s.newValueOrSfCall1(op2, tt, s.newValueOrSfCall1(op1, types.Types[it], v))
  2980  		}
  2981  		// Tricky 64-bit unsigned cases.
  2982  		if ft.IsInteger() {
  2983  			// tt is float32 or float64, and ft is also unsigned
  2984  			if tt.Size() == 4 {
  2985  				return s.uint64Tofloat32(n, v, ft, tt)
  2986  			}
  2987  			if tt.Size() == 8 {
  2988  				return s.uint64Tofloat64(n, v, ft, tt)
  2989  			}
  2990  			s.Fatalf("weird unsigned integer to float conversion %v -> %v", ft, tt)
  2991  		}
  2992  		// ft is float32 or float64, and tt is unsigned integer
  2993  		if ft.Size() == 4 {
  2994  			switch tt.Size() {
  2995  			case 8:
  2996  				return s.float32ToUint64(n, v, ft, tt)
  2997  			case 4, 2, 1:
  2998  				// TODO should 2 and 1 saturate or truncate?
  2999  				return s.float32ToUint32(n, v, ft, tt)
  3000  			}
  3001  		}
  3002  		if ft.Size() == 8 {
  3003  			switch tt.Size() {
  3004  			case 8:
  3005  				return s.float64ToUint64(n, v, ft, tt)
  3006  			case 4, 2, 1:
  3007  				// TODO should 2 and 1 saturate or truncate?
  3008  				return s.float64ToUint32(n, v, ft, tt)
  3009  			}
  3010  
  3011  		}
  3012  		s.Fatalf("weird float to unsigned integer conversion %v -> %v", ft, tt)
  3013  		return nil
  3014  	}
  3015  
  3016  	s.Fatalf("unhandled OCONV %s -> %s", ft.Kind(), tt.Kind())
  3017  	return nil
  3018  }
  3019  
  3020  // expr converts the expression n to ssa, adds it to s and returns the ssa result.
  3021  func (s *state) expr(n ir.Node) *ssa.Value {
  3022  	return s.exprCheckPtr(n, true)
  3023  }
  3024  
  3025  func (s *state) exprCheckPtr(n ir.Node, checkPtrOK bool) *ssa.Value {
  3026  	if ir.HasUniquePos(n) {
  3027  		// ONAMEs and named OLITERALs have the line number
  3028  		// of the decl, not the use. See issue 14742.
  3029  		s.pushLine(n.Pos())
  3030  		defer s.popLine()
  3031  	}
  3032  
  3033  	s.stmtList(n.Init())
  3034  	switch n.Op() {
  3035  	case ir.OBYTES2STRTMP:
  3036  		n := n.(*ir.ConvExpr)
  3037  		slice := s.expr(n.X)
  3038  		ptr := s.newValue1(ssa.OpSlicePtr, s.f.Config.Types.BytePtr, slice)
  3039  		len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3040  		return s.newValue2(ssa.OpStringMake, n.Type(), ptr, len)
  3041  	case ir.OSTR2BYTESTMP:
  3042  		n := n.(*ir.ConvExpr)
  3043  		str := s.expr(n.X)
  3044  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, str)
  3045  		if !n.NonNil() {
  3046  			// We need to ensure []byte("") evaluates to []byte{}, and not []byte(nil).
  3047  			//
  3048  			// TODO(mdempsky): Investigate using "len != 0" instead of "ptr != nil".
  3049  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], ptr, s.constNil(ptr.Type))
  3050  			zerobase := s.newValue1A(ssa.OpAddr, ptr.Type, ir.Syms.Zerobase, s.sb)
  3051  			ptr = s.ternary(cond, ptr, zerobase)
  3052  		}
  3053  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], str)
  3054  		return s.newValue3(ssa.OpSliceMake, n.Type(), ptr, len, len)
  3055  	case ir.OCFUNC:
  3056  		n := n.(*ir.UnaryExpr)
  3057  		aux := n.X.(*ir.Name).Linksym()
  3058  		// OCFUNC is used to build function values, which must
  3059  		// always reference ABIInternal entry points.
  3060  		if aux.ABI() != obj.ABIInternal {
  3061  			s.Fatalf("expected ABIInternal: %v", aux.ABI())
  3062  		}
  3063  		return s.entryNewValue1A(ssa.OpAddr, n.Type(), aux, s.sb)
  3064  	case ir.ONAME:
  3065  		n := n.(*ir.Name)
  3066  		if n.Class == ir.PFUNC {
  3067  			// "value" of a function is the address of the function's closure
  3068  			sym := staticdata.FuncLinksym(n)
  3069  			return s.entryNewValue1A(ssa.OpAddr, types.NewPtr(n.Type()), sym, s.sb)
  3070  		}
  3071  		if s.canSSA(n) {
  3072  			return s.variable(n, n.Type())
  3073  		}
  3074  		return s.load(n.Type(), s.addr(n))
  3075  	case ir.OLINKSYMOFFSET:
  3076  		n := n.(*ir.LinksymOffsetExpr)
  3077  		return s.load(n.Type(), s.addr(n))
  3078  	case ir.ONIL:
  3079  		n := n.(*ir.NilExpr)
  3080  		t := n.Type()
  3081  		switch {
  3082  		case t.IsSlice():
  3083  			return s.constSlice(t)
  3084  		case t.IsInterface():
  3085  			return s.constInterface(t)
  3086  		default:
  3087  			return s.constNil(t)
  3088  		}
  3089  	case ir.OLITERAL:
  3090  		switch u := n.Val(); u.Kind() {
  3091  		case constant.Int:
  3092  			i := ir.IntVal(n.Type(), u)
  3093  			switch n.Type().Size() {
  3094  			case 1:
  3095  				return s.constInt8(n.Type(), int8(i))
  3096  			case 2:
  3097  				return s.constInt16(n.Type(), int16(i))
  3098  			case 4:
  3099  				return s.constInt32(n.Type(), int32(i))
  3100  			case 8:
  3101  				return s.constInt64(n.Type(), i)
  3102  			default:
  3103  				s.Fatalf("bad integer size %d", n.Type().Size())
  3104  				return nil
  3105  			}
  3106  		case constant.String:
  3107  			i := constant.StringVal(u)
  3108  			if i == "" {
  3109  				return s.constEmptyString(n.Type())
  3110  			}
  3111  			return s.entryNewValue0A(ssa.OpConstString, n.Type(), ssa.StringToAux(i))
  3112  		case constant.Bool:
  3113  			return s.constBool(constant.BoolVal(u))
  3114  		case constant.Float:
  3115  			f, _ := constant.Float64Val(u)
  3116  			switch n.Type().Size() {
  3117  			case 4:
  3118  				return s.constFloat32(n.Type(), f)
  3119  			case 8:
  3120  				return s.constFloat64(n.Type(), f)
  3121  			default:
  3122  				s.Fatalf("bad float size %d", n.Type().Size())
  3123  				return nil
  3124  			}
  3125  		case constant.Complex:
  3126  			re, _ := constant.Float64Val(constant.Real(u))
  3127  			im, _ := constant.Float64Val(constant.Imag(u))
  3128  			switch n.Type().Size() {
  3129  			case 8:
  3130  				pt := types.Types[types.TFLOAT32]
  3131  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  3132  					s.constFloat32(pt, re),
  3133  					s.constFloat32(pt, im))
  3134  			case 16:
  3135  				pt := types.Types[types.TFLOAT64]
  3136  				return s.newValue2(ssa.OpComplexMake, n.Type(),
  3137  					s.constFloat64(pt, re),
  3138  					s.constFloat64(pt, im))
  3139  			default:
  3140  				s.Fatalf("bad complex size %d", n.Type().Size())
  3141  				return nil
  3142  			}
  3143  		default:
  3144  			s.Fatalf("unhandled OLITERAL %v", u.Kind())
  3145  			return nil
  3146  		}
  3147  	case ir.OCONVNOP:
  3148  		n := n.(*ir.ConvExpr)
  3149  		to := n.Type()
  3150  		from := n.X.Type()
  3151  
  3152  		// Assume everything will work out, so set up our return value.
  3153  		// Anything interesting that happens from here is a fatal.
  3154  		x := s.expr(n.X)
  3155  		if to == from {
  3156  			return x
  3157  		}
  3158  
  3159  		// Special case for not confusing GC and liveness.
  3160  		// We don't want pointers accidentally classified
  3161  		// as not-pointers or vice-versa because of copy
  3162  		// elision.
  3163  		if to.IsPtrShaped() != from.IsPtrShaped() {
  3164  			return s.newValue2(ssa.OpConvert, to, x, s.mem())
  3165  		}
  3166  
  3167  		v := s.newValue1(ssa.OpCopy, to, x) // ensure that v has the right type
  3168  
  3169  		// CONVNOP closure
  3170  		if to.Kind() == types.TFUNC && from.IsPtrShaped() {
  3171  			return v
  3172  		}
  3173  
  3174  		// named <--> unnamed type or typed <--> untyped const
  3175  		if from.Kind() == to.Kind() {
  3176  			return v
  3177  		}
  3178  
  3179  		// unsafe.Pointer <--> *T
  3180  		if to.IsUnsafePtr() && from.IsPtrShaped() || from.IsUnsafePtr() && to.IsPtrShaped() {
  3181  			if s.checkPtrEnabled && checkPtrOK && to.IsPtr() && from.IsUnsafePtr() {
  3182  				s.checkPtrAlignment(n, v, nil)
  3183  			}
  3184  			return v
  3185  		}
  3186  
  3187  		// map <--> *internal/runtime/maps.Map
  3188  		mt := types.NewPtr(reflectdata.MapType())
  3189  		if to.Kind() == types.TMAP && from == mt {
  3190  			return v
  3191  		}
  3192  
  3193  		types.CalcSize(from)
  3194  		types.CalcSize(to)
  3195  		if from.Size() != to.Size() {
  3196  			s.Fatalf("CONVNOP width mismatch %v (%d) -> %v (%d)\n", from, from.Size(), to, to.Size())
  3197  			return nil
  3198  		}
  3199  		if etypesign(from.Kind()) != etypesign(to.Kind()) {
  3200  			s.Fatalf("CONVNOP sign mismatch %v (%s) -> %v (%s)\n", from, from.Kind(), to, to.Kind())
  3201  			return nil
  3202  		}
  3203  
  3204  		if base.Flag.Cfg.Instrumenting {
  3205  			// These appear to be fine, but they fail the
  3206  			// integer constraint below, so okay them here.
  3207  			// Sample non-integer conversion: map[string]string -> *uint8
  3208  			return v
  3209  		}
  3210  
  3211  		if etypesign(from.Kind()) == 0 {
  3212  			s.Fatalf("CONVNOP unrecognized non-integer %v -> %v\n", from, to)
  3213  			return nil
  3214  		}
  3215  
  3216  		// integer, same width, same sign
  3217  		return v
  3218  
  3219  	case ir.OCONV:
  3220  		n := n.(*ir.ConvExpr)
  3221  		x := s.expr(n.X)
  3222  		return s.conv(n, x, n.X.Type(), n.Type())
  3223  
  3224  	case ir.ODOTTYPE:
  3225  		n := n.(*ir.TypeAssertExpr)
  3226  		res, _ := s.dottype(n, false)
  3227  		return res
  3228  
  3229  	case ir.ODYNAMICDOTTYPE:
  3230  		n := n.(*ir.DynamicTypeAssertExpr)
  3231  		res, _ := s.dynamicDottype(n, false)
  3232  		return res
  3233  
  3234  	// binary ops
  3235  	case ir.OLT, ir.OEQ, ir.ONE, ir.OLE, ir.OGE, ir.OGT:
  3236  		n := n.(*ir.BinaryExpr)
  3237  		a := s.expr(n.X)
  3238  		b := s.expr(n.Y)
  3239  		if n.X.Type().IsComplex() {
  3240  			pt := types.FloatForComplex(n.X.Type())
  3241  			op := s.ssaOp(ir.OEQ, pt)
  3242  			r := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b))
  3243  			i := s.newValueOrSfCall2(op, types.Types[types.TBOOL], s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b))
  3244  			c := s.newValue2(ssa.OpAndB, types.Types[types.TBOOL], r, i)
  3245  			switch n.Op() {
  3246  			case ir.OEQ:
  3247  				return c
  3248  			case ir.ONE:
  3249  				return s.newValue1(ssa.OpNot, types.Types[types.TBOOL], c)
  3250  			default:
  3251  				s.Fatalf("ordered complex compare %v", n.Op())
  3252  			}
  3253  		}
  3254  
  3255  		// Convert OGE and OGT into OLE and OLT.
  3256  		op := n.Op()
  3257  		switch op {
  3258  		case ir.OGE:
  3259  			op, a, b = ir.OLE, b, a
  3260  		case ir.OGT:
  3261  			op, a, b = ir.OLT, b, a
  3262  		}
  3263  		if n.X.Type().IsFloat() {
  3264  			// float comparison
  3265  			return s.newValueOrSfCall2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3266  		}
  3267  		// integer comparison
  3268  		return s.newValue2(s.ssaOp(op, n.X.Type()), types.Types[types.TBOOL], a, b)
  3269  	case ir.OMUL:
  3270  		n := n.(*ir.BinaryExpr)
  3271  		a := s.expr(n.X)
  3272  		b := s.expr(n.Y)
  3273  		if n.Type().IsComplex() {
  3274  			mulop := ssa.OpMul64F
  3275  			addop := ssa.OpAdd64F
  3276  			subop := ssa.OpSub64F
  3277  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3278  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3279  
  3280  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3281  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3282  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3283  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3284  
  3285  			if pt != wt { // Widen for calculation
  3286  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3287  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3288  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3289  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3290  			}
  3291  
  3292  			xreal := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3293  			ximag := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, bimag), s.newValueOrSfCall2(mulop, wt, aimag, breal))
  3294  
  3295  			if pt != wt { // Narrow to store back
  3296  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3297  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3298  			}
  3299  
  3300  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3301  		}
  3302  
  3303  		if n.Type().IsFloat() {
  3304  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3305  		}
  3306  
  3307  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3308  
  3309  	case ir.ODIV:
  3310  		n := n.(*ir.BinaryExpr)
  3311  		a := s.expr(n.X)
  3312  		b := s.expr(n.Y)
  3313  		if n.Type().IsComplex() {
  3314  			// TODO this is not executed because the front-end substitutes a runtime call.
  3315  			// That probably ought to change; with modest optimization the widen/narrow
  3316  			// conversions could all be elided in larger expression trees.
  3317  			mulop := ssa.OpMul64F
  3318  			addop := ssa.OpAdd64F
  3319  			subop := ssa.OpSub64F
  3320  			divop := ssa.OpDiv64F
  3321  			pt := types.FloatForComplex(n.Type()) // Could be Float32 or Float64
  3322  			wt := types.Types[types.TFLOAT64]     // Compute in Float64 to minimize cancellation error
  3323  
  3324  			areal := s.newValue1(ssa.OpComplexReal, pt, a)
  3325  			breal := s.newValue1(ssa.OpComplexReal, pt, b)
  3326  			aimag := s.newValue1(ssa.OpComplexImag, pt, a)
  3327  			bimag := s.newValue1(ssa.OpComplexImag, pt, b)
  3328  
  3329  			if pt != wt { // Widen for calculation
  3330  				areal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, areal)
  3331  				breal = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, breal)
  3332  				aimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, aimag)
  3333  				bimag = s.newValueOrSfCall1(ssa.OpCvt32Fto64F, wt, bimag)
  3334  			}
  3335  
  3336  			denom := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, breal, breal), s.newValueOrSfCall2(mulop, wt, bimag, bimag))
  3337  			xreal := s.newValueOrSfCall2(addop, wt, s.newValueOrSfCall2(mulop, wt, areal, breal), s.newValueOrSfCall2(mulop, wt, aimag, bimag))
  3338  			ximag := s.newValueOrSfCall2(subop, wt, s.newValueOrSfCall2(mulop, wt, aimag, breal), s.newValueOrSfCall2(mulop, wt, areal, bimag))
  3339  
  3340  			// TODO not sure if this is best done in wide precision or narrow
  3341  			// Double-rounding might be an issue.
  3342  			// Note that the pre-SSA implementation does the entire calculation
  3343  			// in wide format, so wide is compatible.
  3344  			xreal = s.newValueOrSfCall2(divop, wt, xreal, denom)
  3345  			ximag = s.newValueOrSfCall2(divop, wt, ximag, denom)
  3346  
  3347  			if pt != wt { // Narrow to store back
  3348  				xreal = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, xreal)
  3349  				ximag = s.newValueOrSfCall1(ssa.OpCvt64Fto32F, pt, ximag)
  3350  			}
  3351  			return s.newValue2(ssa.OpComplexMake, n.Type(), xreal, ximag)
  3352  		}
  3353  		if n.Type().IsFloat() {
  3354  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3355  		}
  3356  		return s.intDivide(n, a, b)
  3357  	case ir.OMOD:
  3358  		n := n.(*ir.BinaryExpr)
  3359  		a := s.expr(n.X)
  3360  		b := s.expr(n.Y)
  3361  		return s.intDivide(n, a, b)
  3362  	case ir.OADD, ir.OSUB:
  3363  		n := n.(*ir.BinaryExpr)
  3364  		a := s.expr(n.X)
  3365  		b := s.expr(n.Y)
  3366  		if n.Type().IsComplex() {
  3367  			pt := types.FloatForComplex(n.Type())
  3368  			op := s.ssaOp(n.Op(), pt)
  3369  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3370  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexReal, pt, a), s.newValue1(ssa.OpComplexReal, pt, b)),
  3371  				s.newValueOrSfCall2(op, pt, s.newValue1(ssa.OpComplexImag, pt, a), s.newValue1(ssa.OpComplexImag, pt, b)))
  3372  		}
  3373  		if n.Type().IsFloat() {
  3374  			return s.newValueOrSfCall2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3375  		}
  3376  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3377  	case ir.OAND, ir.OOR, ir.OXOR:
  3378  		n := n.(*ir.BinaryExpr)
  3379  		a := s.expr(n.X)
  3380  		b := s.expr(n.Y)
  3381  		return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  3382  	case ir.OANDNOT:
  3383  		n := n.(*ir.BinaryExpr)
  3384  		a := s.expr(n.X)
  3385  		b := s.expr(n.Y)
  3386  		b = s.newValue1(s.ssaOp(ir.OBITNOT, b.Type), b.Type, b)
  3387  		return s.newValue2(s.ssaOp(ir.OAND, n.Type()), a.Type, a, b)
  3388  	case ir.OLSH, ir.ORSH:
  3389  		n := n.(*ir.BinaryExpr)
  3390  		a := s.expr(n.X)
  3391  		b := s.expr(n.Y)
  3392  		bt := b.Type
  3393  		if bt.IsSigned() {
  3394  			cmp := s.newValue2(s.ssaOp(ir.OLE, bt), types.Types[types.TBOOL], s.zeroVal(bt), b)
  3395  			s.check(cmp, ir.Syms.Panicshift)
  3396  			bt = bt.ToUnsigned()
  3397  		}
  3398  		return s.newValue2(s.ssaShiftOp(n.Op(), n.Type(), bt), a.Type, a, b)
  3399  	case ir.OANDAND, ir.OOROR:
  3400  		// To implement OANDAND (and OOROR), we introduce a
  3401  		// new temporary variable to hold the result. The
  3402  		// variable is associated with the OANDAND node in the
  3403  		// s.vars table (normally variables are only
  3404  		// associated with ONAME nodes). We convert
  3405  		//     A && B
  3406  		// to
  3407  		//     var = A
  3408  		//     if var {
  3409  		//         var = B
  3410  		//     }
  3411  		// Using var in the subsequent block introduces the
  3412  		// necessary phi variable.
  3413  		n := n.(*ir.LogicalExpr)
  3414  		el := s.expr(n.X)
  3415  		s.vars[n] = el
  3416  
  3417  		b := s.endBlock()
  3418  		b.Kind = ssa.BlockIf
  3419  		b.SetControl(el)
  3420  		// In theory, we should set b.Likely here based on context.
  3421  		// However, gc only gives us likeliness hints
  3422  		// in a single place, for plain OIF statements,
  3423  		// and passing around context is finicky, so don't bother for now.
  3424  
  3425  		bRight := s.f.NewBlock(ssa.BlockPlain)
  3426  		bResult := s.f.NewBlock(ssa.BlockPlain)
  3427  		if n.Op() == ir.OANDAND {
  3428  			b.AddEdgeTo(bRight)
  3429  			b.AddEdgeTo(bResult)
  3430  		} else if n.Op() == ir.OOROR {
  3431  			b.AddEdgeTo(bResult)
  3432  			b.AddEdgeTo(bRight)
  3433  		}
  3434  
  3435  		s.startBlock(bRight)
  3436  		er := s.expr(n.Y)
  3437  		s.vars[n] = er
  3438  
  3439  		b = s.endBlock()
  3440  		b.AddEdgeTo(bResult)
  3441  
  3442  		s.startBlock(bResult)
  3443  		return s.variable(n, types.Types[types.TBOOL])
  3444  	case ir.OCOMPLEX:
  3445  		n := n.(*ir.BinaryExpr)
  3446  		r := s.expr(n.X)
  3447  		i := s.expr(n.Y)
  3448  		return s.newValue2(ssa.OpComplexMake, n.Type(), r, i)
  3449  
  3450  	// unary ops
  3451  	case ir.ONEG:
  3452  		n := n.(*ir.UnaryExpr)
  3453  		a := s.expr(n.X)
  3454  		if n.Type().IsComplex() {
  3455  			tp := types.FloatForComplex(n.Type())
  3456  			negop := s.ssaOp(n.Op(), tp)
  3457  			return s.newValue2(ssa.OpComplexMake, n.Type(),
  3458  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexReal, tp, a)),
  3459  				s.newValue1(negop, tp, s.newValue1(ssa.OpComplexImag, tp, a)))
  3460  		}
  3461  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3462  	case ir.ONOT, ir.OBITNOT:
  3463  		n := n.(*ir.UnaryExpr)
  3464  		a := s.expr(n.X)
  3465  		return s.newValue1(s.ssaOp(n.Op(), n.Type()), a.Type, a)
  3466  	case ir.OIMAG, ir.OREAL:
  3467  		n := n.(*ir.UnaryExpr)
  3468  		a := s.expr(n.X)
  3469  		return s.newValue1(s.ssaOp(n.Op(), n.X.Type()), n.Type(), a)
  3470  	case ir.OPLUS:
  3471  		n := n.(*ir.UnaryExpr)
  3472  		return s.expr(n.X)
  3473  
  3474  	case ir.OADDR:
  3475  		n := n.(*ir.AddrExpr)
  3476  		return s.addr(n.X)
  3477  
  3478  	case ir.ORESULT:
  3479  		n := n.(*ir.ResultExpr)
  3480  		if s.prevCall == nil || s.prevCall.Op != ssa.OpStaticLECall && s.prevCall.Op != ssa.OpInterLECall && s.prevCall.Op != ssa.OpClosureLECall {
  3481  			panic("Expected to see a previous call")
  3482  		}
  3483  		which := n.Index
  3484  		if which == -1 {
  3485  			panic(fmt.Errorf("ORESULT %v does not match call %s", n, s.prevCall))
  3486  		}
  3487  		return s.resultOfCall(s.prevCall, which, n.Type())
  3488  
  3489  	case ir.ODEREF:
  3490  		n := n.(*ir.StarExpr)
  3491  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3492  		return s.load(n.Type(), p)
  3493  
  3494  	case ir.ODOT:
  3495  		n := n.(*ir.SelectorExpr)
  3496  		if n.X.Op() == ir.OSTRUCTLIT {
  3497  			// All literals with nonzero fields have already been
  3498  			// rewritten during walk. Any that remain are just T{}
  3499  			// or equivalents. Use the zero value.
  3500  			if !ir.IsZero(n.X) {
  3501  				s.Fatalf("literal with nonzero value in SSA: %v", n.X)
  3502  			}
  3503  			return s.zeroVal(n.Type())
  3504  		}
  3505  		// If n is addressable and can't be represented in
  3506  		// SSA, then load just the selected field. This
  3507  		// prevents false memory dependencies in race/msan/asan
  3508  		// instrumentation.
  3509  		if ir.IsAddressable(n) && !s.canSSA(n) {
  3510  			p := s.addr(n)
  3511  			return s.load(n.Type(), p)
  3512  		}
  3513  		v := s.expr(n.X)
  3514  		return s.newValue1I(ssa.OpStructSelect, n.Type(), int64(fieldIdx(n)), v)
  3515  
  3516  	case ir.ODOTPTR:
  3517  		n := n.(*ir.SelectorExpr)
  3518  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  3519  		p = s.newValue1I(ssa.OpOffPtr, types.NewPtr(n.Type()), n.Offset(), p)
  3520  		return s.load(n.Type(), p)
  3521  
  3522  	case ir.OINDEX:
  3523  		n := n.(*ir.IndexExpr)
  3524  		switch {
  3525  		case n.X.Type().IsString():
  3526  			if n.Bounded() && ir.IsConst(n.X, constant.String) && ir.IsConst(n.Index, constant.Int) {
  3527  				// Replace "abc"[1] with 'b'.
  3528  				// Delayed until now because "abc"[1] is not an ideal constant.
  3529  				// See test/fixedbugs/issue11370.go.
  3530  				return s.newValue0I(ssa.OpConst8, types.Types[types.TUINT8], int64(int8(ir.StringVal(n.X)[ir.Int64Val(n.Index)])))
  3531  			}
  3532  			a := s.expr(n.X)
  3533  			i := s.expr(n.Index)
  3534  			len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3535  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  3536  			ptrtyp := s.f.Config.Types.BytePtr
  3537  			ptr := s.newValue1(ssa.OpStringPtr, ptrtyp, a)
  3538  			if ir.IsConst(n.Index, constant.Int) {
  3539  				ptr = s.newValue1I(ssa.OpOffPtr, ptrtyp, ir.Int64Val(n.Index), ptr)
  3540  			} else {
  3541  				ptr = s.newValue2(ssa.OpAddPtr, ptrtyp, ptr, i)
  3542  			}
  3543  			return s.load(types.Types[types.TUINT8], ptr)
  3544  		case n.X.Type().IsSlice():
  3545  			p := s.addr(n)
  3546  			return s.load(n.X.Type().Elem(), p)
  3547  		case n.X.Type().IsArray():
  3548  			if ssa.CanSSA(n.X.Type()) {
  3549  				// SSA can handle arrays of length at most 1.
  3550  				bound := n.X.Type().NumElem()
  3551  				a := s.expr(n.X)
  3552  				i := s.expr(n.Index)
  3553  				if bound == 0 {
  3554  					// Bounds check will never succeed.  Might as well
  3555  					// use constants for the bounds check.
  3556  					z := s.constInt(types.Types[types.TINT], 0)
  3557  					s.boundsCheck(z, z, ssa.BoundsIndex, false)
  3558  					// The return value won't be live. In case bounds checks
  3559  					// are turned off, load from (*T)(nil) to cause a segfault.
  3560  					return s.load(n.Type(), s.constNil(n.Type().PtrTo()))
  3561  				}
  3562  				len := s.constInt(types.Types[types.TINT], bound)
  3563  				s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded()) // checks i == 0
  3564  				return s.newValue1I(ssa.OpArraySelect, n.Type(), 0, a)
  3565  			}
  3566  			p := s.addr(n)
  3567  			return s.load(n.X.Type().Elem(), p)
  3568  		default:
  3569  			s.Fatalf("bad type for index %v", n.X.Type())
  3570  			return nil
  3571  		}
  3572  
  3573  	case ir.OLEN, ir.OCAP:
  3574  		n := n.(*ir.UnaryExpr)
  3575  		// Note: all constant cases are handled by the frontend. If len or cap
  3576  		// makes it here, we want the side effects of the argument. See issue 72844.
  3577  		a := s.expr(n.X)
  3578  		t := n.X.Type()
  3579  		switch {
  3580  		case t.IsSlice():
  3581  			op := ssa.OpSliceLen
  3582  			if n.Op() == ir.OCAP {
  3583  				op = ssa.OpSliceCap
  3584  			}
  3585  			return s.newValue1(op, types.Types[types.TINT], a)
  3586  		case t.IsString(): // string; not reachable for OCAP
  3587  			return s.newValue1(ssa.OpStringLen, types.Types[types.TINT], a)
  3588  		case t.IsMap(), t.IsChan():
  3589  			return s.referenceTypeBuiltin(n, a)
  3590  		case t.IsArray():
  3591  			return s.constInt(types.Types[types.TINT], t.NumElem())
  3592  		case t.IsPtr() && t.Elem().IsArray():
  3593  			return s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  3594  		default:
  3595  			s.Fatalf("bad type in len/cap: %v", t)
  3596  			return nil
  3597  		}
  3598  
  3599  	case ir.OSPTR:
  3600  		n := n.(*ir.UnaryExpr)
  3601  		a := s.expr(n.X)
  3602  		if n.X.Type().IsSlice() {
  3603  			if n.Bounded() {
  3604  				return s.newValue1(ssa.OpSlicePtr, n.Type(), a)
  3605  			}
  3606  			return s.newValue1(ssa.OpSlicePtrUnchecked, n.Type(), a)
  3607  		} else {
  3608  			return s.newValue1(ssa.OpStringPtr, n.Type(), a)
  3609  		}
  3610  
  3611  	case ir.OITAB:
  3612  		n := n.(*ir.UnaryExpr)
  3613  		a := s.expr(n.X)
  3614  		return s.newValue1(ssa.OpITab, n.Type(), a)
  3615  
  3616  	case ir.OIDATA:
  3617  		n := n.(*ir.UnaryExpr)
  3618  		a := s.expr(n.X)
  3619  		return s.newValue1(ssa.OpIData, n.Type(), a)
  3620  
  3621  	case ir.OMAKEFACE:
  3622  		n := n.(*ir.BinaryExpr)
  3623  		tab := s.expr(n.X)
  3624  		data := s.expr(n.Y)
  3625  		return s.newValue2(ssa.OpIMake, n.Type(), tab, data)
  3626  
  3627  	case ir.OSLICEHEADER:
  3628  		n := n.(*ir.SliceHeaderExpr)
  3629  		p := s.expr(n.Ptr)
  3630  		l := s.expr(n.Len)
  3631  		c := s.expr(n.Cap)
  3632  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3633  
  3634  	case ir.OSTRINGHEADER:
  3635  		n := n.(*ir.StringHeaderExpr)
  3636  		p := s.expr(n.Ptr)
  3637  		l := s.expr(n.Len)
  3638  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3639  
  3640  	case ir.OSLICE, ir.OSLICEARR, ir.OSLICE3, ir.OSLICE3ARR:
  3641  		n := n.(*ir.SliceExpr)
  3642  		check := s.checkPtrEnabled && n.Op() == ir.OSLICE3ARR && n.X.Op() == ir.OCONVNOP && n.X.(*ir.ConvExpr).X.Type().IsUnsafePtr()
  3643  		v := s.exprCheckPtr(n.X, !check)
  3644  		var i, j, k *ssa.Value
  3645  		if n.Low != nil {
  3646  			i = s.expr(n.Low)
  3647  		}
  3648  		if n.High != nil {
  3649  			j = s.expr(n.High)
  3650  		}
  3651  		if n.Max != nil {
  3652  			k = s.expr(n.Max)
  3653  		}
  3654  		p, l, c := s.slice(v, i, j, k, n.Bounded())
  3655  		if check {
  3656  			// Emit checkptr instrumentation after bound check to prevent false positive, see #46938.
  3657  			s.checkPtrAlignment(n.X.(*ir.ConvExpr), v, s.conv(n.Max, k, k.Type, types.Types[types.TUINTPTR]))
  3658  		}
  3659  		return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  3660  
  3661  	case ir.OSLICESTR:
  3662  		n := n.(*ir.SliceExpr)
  3663  		v := s.expr(n.X)
  3664  		var i, j *ssa.Value
  3665  		if n.Low != nil {
  3666  			i = s.expr(n.Low)
  3667  		}
  3668  		if n.High != nil {
  3669  			j = s.expr(n.High)
  3670  		}
  3671  		p, l, _ := s.slice(v, i, j, nil, n.Bounded())
  3672  		return s.newValue2(ssa.OpStringMake, n.Type(), p, l)
  3673  
  3674  	case ir.OSLICE2ARRPTR:
  3675  		// if arrlen > slice.len {
  3676  		//   panic(...)
  3677  		// }
  3678  		// slice.ptr
  3679  		n := n.(*ir.ConvExpr)
  3680  		v := s.expr(n.X)
  3681  		nelem := n.Type().Elem().NumElem()
  3682  		arrlen := s.constInt(types.Types[types.TINT], nelem)
  3683  		cap := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  3684  		s.boundsCheck(arrlen, cap, ssa.BoundsConvert, false)
  3685  		op := ssa.OpSlicePtr
  3686  		if nelem == 0 {
  3687  			op = ssa.OpSlicePtrUnchecked
  3688  		}
  3689  		return s.newValue1(op, n.Type(), v)
  3690  
  3691  	case ir.OCALLFUNC:
  3692  		n := n.(*ir.CallExpr)
  3693  		if ir.IsIntrinsicCall(n) {
  3694  			return s.intrinsicCall(n)
  3695  		}
  3696  		fallthrough
  3697  
  3698  	case ir.OCALLINTER:
  3699  		n := n.(*ir.CallExpr)
  3700  		return s.callResult(n, callNormal)
  3701  
  3702  	case ir.OGETG:
  3703  		n := n.(*ir.CallExpr)
  3704  		return s.newValue1(ssa.OpGetG, n.Type(), s.mem())
  3705  
  3706  	case ir.OGETCALLERSP:
  3707  		n := n.(*ir.CallExpr)
  3708  		return s.newValue1(ssa.OpGetCallerSP, n.Type(), s.mem())
  3709  
  3710  	case ir.OAPPEND:
  3711  		return s.append(n.(*ir.CallExpr), false)
  3712  
  3713  	case ir.OMOVE2HEAP:
  3714  		return s.move2heap(n.(*ir.MoveToHeapExpr))
  3715  
  3716  	case ir.OMIN, ir.OMAX:
  3717  		return s.minMax(n.(*ir.CallExpr))
  3718  
  3719  	case ir.OSTRUCTLIT, ir.OARRAYLIT:
  3720  		// All literals with nonzero fields have already been
  3721  		// rewritten during walk. Any that remain are just T{}
  3722  		// or equivalents. Use the zero value.
  3723  		n := n.(*ir.CompLitExpr)
  3724  		if !ir.IsZero(n) {
  3725  			s.Fatalf("literal with nonzero value in SSA: %v", n)
  3726  		}
  3727  		return s.zeroVal(n.Type())
  3728  
  3729  	case ir.ONEW:
  3730  		n := n.(*ir.UnaryExpr)
  3731  		if x, ok := n.X.(*ir.DynamicType); ok && x.Op() == ir.ODYNAMICTYPE {
  3732  			return s.newObjectNonSpecialized(n.Type().Elem(), s.expr(x.RType))
  3733  		}
  3734  		return s.newObject(n.Type().Elem())
  3735  
  3736  	case ir.OUNSAFEADD:
  3737  		n := n.(*ir.BinaryExpr)
  3738  		ptr := s.expr(n.X)
  3739  		len := s.expr(n.Y)
  3740  
  3741  		// Force len to uintptr to prevent misuse of garbage bits in the
  3742  		// upper part of the register (#48536).
  3743  		len = s.conv(n, len, len.Type, types.Types[types.TUINTPTR])
  3744  
  3745  		return s.newValue2(ssa.OpAddPtr, n.Type(), ptr, len)
  3746  
  3747  	default:
  3748  		s.Fatalf("unhandled expr %v", n.Op())
  3749  		return nil
  3750  	}
  3751  }
  3752  
  3753  func (s *state) resultOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3754  	aux := c.Aux.(*ssa.AuxCall)
  3755  	pa := aux.ParamAssignmentForResult(which)
  3756  	// TODO(register args) determine if in-memory TypeOK is better loaded early from SelectNAddr or later when SelectN is expanded.
  3757  	// SelectN is better for pattern-matching and possible call-aware analysis we might want to do in the future.
  3758  	if len(pa.Registers) == 0 && !ssa.CanSSA(t) {
  3759  		addr := s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3760  		return s.rawLoad(t, addr)
  3761  	}
  3762  	return s.newValue1I(ssa.OpSelectN, t, which, c)
  3763  }
  3764  
  3765  func (s *state) resultAddrOfCall(c *ssa.Value, which int64, t *types.Type) *ssa.Value {
  3766  	aux := c.Aux.(*ssa.AuxCall)
  3767  	pa := aux.ParamAssignmentForResult(which)
  3768  	if len(pa.Registers) == 0 {
  3769  		return s.newValue1I(ssa.OpSelectNAddr, types.NewPtr(t), which, c)
  3770  	}
  3771  	_, addr := s.temp(c.Pos, t)
  3772  	rval := s.newValue1I(ssa.OpSelectN, t, which, c)
  3773  	s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, addr, rval, s.mem(), false)
  3774  	return addr
  3775  }
  3776  
  3777  // Get backing store information for an append call.
  3778  func (s *state) getBackingStoreInfoForAppend(n *ir.CallExpr) *backingStoreInfo {
  3779  	if n.Esc() != ir.EscNone {
  3780  		return nil
  3781  	}
  3782  	return s.getBackingStoreInfo(n.Args[0])
  3783  }
  3784  func (s *state) getBackingStoreInfo(n ir.Node) *backingStoreInfo {
  3785  	t := n.Type()
  3786  	et := t.Elem()
  3787  	maxStackSize := int64(base.Debug.VariableMakeThreshold)
  3788  	if et.Size() == 0 || et.Size() > maxStackSize {
  3789  		return nil
  3790  	}
  3791  	if base.Flag.N != 0 {
  3792  		return nil
  3793  	}
  3794  	if !base.VariableMakeHash.MatchPos(n.Pos(), nil) {
  3795  		return nil
  3796  	}
  3797  	i := s.backingStores[n]
  3798  	if i != nil {
  3799  		return i
  3800  	}
  3801  
  3802  	// Build type of backing store.
  3803  	K := maxStackSize / et.Size() // rounds down
  3804  	KT := types.NewArray(et, K)
  3805  	KT.SetNoalg(true)
  3806  	types.CalcArraySize(KT)
  3807  	// Align more than naturally for the type KT. See issue 73199.
  3808  	align := types.NewArray(types.Types[types.TUINTPTR], 0)
  3809  	types.CalcArraySize(align)
  3810  	storeTyp := types.NewStruct([]*types.Field{
  3811  		{Sym: types.BlankSym, Type: align},
  3812  		{Sym: types.BlankSym, Type: KT},
  3813  	})
  3814  	storeTyp.SetNoalg(true)
  3815  	types.CalcStructSize(storeTyp)
  3816  
  3817  	// Make backing store variable.
  3818  	backingStore := typecheck.TempAt(n.Pos(), s.curfn, storeTyp)
  3819  	backingStore.SetAddrtaken(true)
  3820  
  3821  	// Make "used" boolean.
  3822  	used := typecheck.TempAt(n.Pos(), s.curfn, types.Types[types.TBOOL])
  3823  	if s.curBlock == s.f.Entry {
  3824  		s.vars[used] = s.constBool(false)
  3825  	} else {
  3826  		// initialize this variable at end of entry block
  3827  		s.defvars[s.f.Entry.ID][used] = s.constBool(false)
  3828  	}
  3829  
  3830  	// Initialize an info structure.
  3831  	if s.backingStores == nil {
  3832  		s.backingStores = map[ir.Node]*backingStoreInfo{}
  3833  	}
  3834  	i = &backingStoreInfo{K: K, store: backingStore, used: used, usedStatic: false}
  3835  	s.backingStores[n] = i
  3836  	return i
  3837  }
  3838  
  3839  // append converts an OAPPEND node to SSA.
  3840  // If inplace is false, it converts the OAPPEND expression n to an ssa.Value,
  3841  // adds it to s, and returns the Value.
  3842  // If inplace is true, it writes the result of the OAPPEND expression n
  3843  // back to the slice being appended to, and returns nil.
  3844  // inplace MUST be set to false if the slice can be SSA'd.
  3845  // Note: this code only handles fixed-count appends. Dotdotdot appends
  3846  // have already been rewritten at this point (by walk).
  3847  func (s *state) append(n *ir.CallExpr, inplace bool) *ssa.Value {
  3848  	// If inplace is false, process as expression "append(s, e1, e2, e3)":
  3849  	//
  3850  	// ptr, len, cap := s
  3851  	// len += 3
  3852  	// if uint(len) > uint(cap) {
  3853  	//     ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3854  	//     Note that len is unmodified by growslice.
  3855  	// }
  3856  	// // with write barriers, if needed:
  3857  	// *(ptr+(len-3)) = e1
  3858  	// *(ptr+(len-2)) = e2
  3859  	// *(ptr+(len-1)) = e3
  3860  	// return makeslice(ptr, len, cap)
  3861  	//
  3862  	//
  3863  	// If inplace is true, process as statement "s = append(s, e1, e2, e3)":
  3864  	//
  3865  	// a := &s
  3866  	// ptr, len, cap := s
  3867  	// len += 3
  3868  	// if uint(len) > uint(cap) {
  3869  	//    ptr, len, cap = growslice(ptr, len, cap, 3, typ)
  3870  	//    vardef(a)    // if necessary, advise liveness we are writing a new a
  3871  	//    *a.cap = cap // write before ptr to avoid a spill
  3872  	//    *a.ptr = ptr // with write barrier
  3873  	// }
  3874  	// *a.len = len
  3875  	// // with write barriers, if needed:
  3876  	// *(ptr+(len-3)) = e1
  3877  	// *(ptr+(len-2)) = e2
  3878  	// *(ptr+(len-1)) = e3
  3879  
  3880  	et := n.Type().Elem()
  3881  	pt := types.NewPtr(et)
  3882  
  3883  	// Evaluate slice
  3884  	sn := n.Args[0] // the slice node is the first in the list
  3885  	var slice, addr *ssa.Value
  3886  	if inplace {
  3887  		addr = s.addr(sn)
  3888  		slice = s.load(n.Type(), addr)
  3889  	} else {
  3890  		slice = s.expr(sn)
  3891  	}
  3892  
  3893  	// Allocate new blocks
  3894  	grow := s.f.NewBlock(ssa.BlockPlain)
  3895  	assign := s.f.NewBlock(ssa.BlockPlain)
  3896  
  3897  	// Decomposse input slice.
  3898  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  3899  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  3900  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  3901  
  3902  	// Add number of new elements to length.
  3903  	nargs := s.constInt(types.Types[types.TINT], int64(len(n.Args)-1))
  3904  	oldLen := l
  3905  	l = s.newValue2(s.ssaOp(ir.OADD, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  3906  
  3907  	// Decide if we need to grow
  3908  	cmp := s.newValue2(s.ssaOp(ir.OLT, types.Types[types.TUINT]), types.Types[types.TBOOL], c, l)
  3909  
  3910  	// Record values of ptr/len/cap before branch.
  3911  	s.vars[ptrVar] = p
  3912  	s.vars[lenVar] = l
  3913  	if !inplace {
  3914  		s.vars[capVar] = c
  3915  	}
  3916  
  3917  	b := s.endBlock()
  3918  	b.Kind = ssa.BlockIf
  3919  	b.Likely = ssa.BranchUnlikely
  3920  	b.SetControl(cmp)
  3921  	b.AddEdgeTo(grow)
  3922  	b.AddEdgeTo(assign)
  3923  
  3924  	// If the result of the append does not escape, we can use
  3925  	// a stack-allocated backing store if len is small enough.
  3926  	// A stack-allocated backing store could be used at every
  3927  	// append that qualifies, but we limit it in some cases to
  3928  	// avoid wasted code and stack space.
  3929  	//
  3930  	// Note that we have two different strategies.
  3931  	// 1. The standard strategy is just to allocate the full
  3932  	//    backing store at the first append.
  3933  	// 2. An alternate strategy is used when
  3934  	//        a. The backing store eventually escapes via move2heap
  3935  	//    and b. The capacity is used somehow
  3936  	//    In this case, we don't want to just allocate
  3937  	//    the full buffer at the first append, because when
  3938  	//    we move2heap the buffer to the heap when it escapes,
  3939  	//    we might end up wasting memory because we can't
  3940  	//    change the capacity.
  3941  	//    So in this case we use growsliceBuf to reuse the buffer
  3942  	//    and walk one step up the size class ladder each time.
  3943  	//
  3944  	// TODO: handle ... append case? Currently we handle only
  3945  	// a fixed number of appended elements.
  3946  	var info *backingStoreInfo
  3947  	if !inplace {
  3948  		info = s.getBackingStoreInfoForAppend(n)
  3949  	}
  3950  
  3951  	if !inplace && info != nil && !n.UseBuf && !info.usedStatic {
  3952  		// if l <= K {
  3953  		//   if !used {
  3954  		//     if oldLen == 0 {
  3955  		//       var store [K]T
  3956  		//       s = store[:l:K]
  3957  		//       used = true
  3958  		//     }
  3959  		//   }
  3960  		// }
  3961  		// ... if we didn't use the stack backing store, call growslice ...
  3962  		//
  3963  		// oldLen==0 is not strictly necessary, but requiring it means
  3964  		// we don't have to worry about copying existing elements.
  3965  		// Allowing oldLen>0 would add complication. Worth it? I would guess not.
  3966  		//
  3967  		// TODO: instead of the used boolean, we could insist that this only applies
  3968  		// to monotonic slices, those which once they have >0 entries never go back
  3969  		// to 0 entries. Then oldLen==0 is enough.
  3970  		//
  3971  		// We also do this for append(x, ...) once for every x.
  3972  		// It is ok to do it more often, but it is probably helpful only for
  3973  		// the first instance. TODO: this could use more tuning. Using ir.Node
  3974  		// as the key works for *ir.Name instances but probably nothing else.
  3975  		info.usedStatic = true
  3976  		// TODO: unset usedStatic somehow?
  3977  
  3978  		usedTestBlock := s.f.NewBlock(ssa.BlockPlain)
  3979  		oldLenTestBlock := s.f.NewBlock(ssa.BlockPlain)
  3980  		bodyBlock := s.f.NewBlock(ssa.BlockPlain)
  3981  		growSlice := s.f.NewBlock(ssa.BlockPlain)
  3982  		tInt := types.Types[types.TINT]
  3983  		tBool := types.Types[types.TBOOL]
  3984  
  3985  		// if l <= K
  3986  		s.startBlock(grow)
  3987  		kTest := s.newValue2(s.ssaOp(ir.OLE, tInt), tBool, l, s.constInt(tInt, info.K))
  3988  		b := s.endBlock()
  3989  		b.Kind = ssa.BlockIf
  3990  		b.SetControl(kTest)
  3991  		b.AddEdgeTo(usedTestBlock)
  3992  		b.AddEdgeTo(growSlice)
  3993  		b.Likely = ssa.BranchLikely
  3994  
  3995  		// if !used
  3996  		s.startBlock(usedTestBlock)
  3997  		usedTest := s.newValue1(ssa.OpNot, tBool, s.expr(info.used))
  3998  		b = s.endBlock()
  3999  		b.Kind = ssa.BlockIf
  4000  		b.SetControl(usedTest)
  4001  		b.AddEdgeTo(oldLenTestBlock)
  4002  		b.AddEdgeTo(growSlice)
  4003  		b.Likely = ssa.BranchLikely
  4004  
  4005  		// if oldLen == 0
  4006  		s.startBlock(oldLenTestBlock)
  4007  		oldLenTest := s.newValue2(s.ssaOp(ir.OEQ, tInt), tBool, oldLen, s.constInt(tInt, 0))
  4008  		b = s.endBlock()
  4009  		b.Kind = ssa.BlockIf
  4010  		b.SetControl(oldLenTest)
  4011  		b.AddEdgeTo(bodyBlock)
  4012  		b.AddEdgeTo(growSlice)
  4013  		b.Likely = ssa.BranchLikely
  4014  
  4015  		// var store struct { _ [0]uintptr; arr [K]T }
  4016  		s.startBlock(bodyBlock)
  4017  		if et.HasPointers() {
  4018  			s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, info.store, s.mem())
  4019  		}
  4020  		addr := s.addr(info.store)
  4021  		s.zero(info.store.Type(), addr)
  4022  
  4023  		// s = store.arr[:l:K]
  4024  		s.vars[ptrVar] = addr
  4025  		s.vars[lenVar] = l // nargs would also be ok because of the oldLen==0 test.
  4026  		s.vars[capVar] = s.constInt(tInt, info.K)
  4027  
  4028  		// used = true
  4029  		s.assign(info.used, s.constBool(true), false, 0)
  4030  		b = s.endBlock()
  4031  		b.AddEdgeTo(assign)
  4032  
  4033  		// New block to use for growslice call.
  4034  		grow = growSlice
  4035  	}
  4036  
  4037  	// Call growslice
  4038  	s.startBlock(grow)
  4039  	taddr := s.expr(n.Fun)
  4040  	var r []*ssa.Value
  4041  	if info != nil && n.UseBuf {
  4042  		// Use stack-allocated buffer as backing store, if we can.
  4043  		if et.HasPointers() && !info.usedStatic {
  4044  			// Initialize in the function header. Not the best place,
  4045  			// but it makes sure we don't scan this area before it is
  4046  			// initialized.
  4047  			mem := s.defvars[s.f.Entry.ID][memVar]
  4048  			mem = s.f.Entry.NewValue1A(n.Pos(), ssa.OpVarDef, types.TypeMem, info.store, mem)
  4049  			addr := s.f.Entry.NewValue2A(n.Pos(), ssa.OpLocalAddr, types.NewPtr(info.store.Type()), info.store, s.sp, mem)
  4050  			mem = s.f.Entry.NewValue2I(n.Pos(), ssa.OpZero, types.TypeMem, info.store.Type().Size(), addr, mem)
  4051  			mem.Aux = info.store.Type()
  4052  			s.defvars[s.f.Entry.ID][memVar] = mem
  4053  			info.usedStatic = true
  4054  		}
  4055  		fn := ir.Syms.GrowsliceBuf
  4056  		if goexperiment.RuntimeFreegc && n.AppendNoAlias && !et.HasPointers() {
  4057  			// The append is for a non-aliased slice where the runtime knows how to free
  4058  			// the old logically dead backing store after growth.
  4059  			// TODO(thepudds): for now, we only use the NoAlias version for element types
  4060  			// without pointers while waiting on additional runtime support (CL 698515).
  4061  			fn = ir.Syms.GrowsliceBufNoAlias
  4062  		}
  4063  		r = s.rtcall(fn, true, []*types.Type{n.Type()}, p, l, c, nargs, taddr, s.addr(info.store), s.constInt(types.Types[types.TINT], info.K))
  4064  	} else {
  4065  		fn := ir.Syms.Growslice
  4066  		if goexperiment.RuntimeFreegc && n.AppendNoAlias && !et.HasPointers() {
  4067  			// The append is for a non-aliased slice where the runtime knows how to free
  4068  			// the old logically dead backing store after growth.
  4069  			// TODO(thepudds): for now, we only use the NoAlias version for element types
  4070  			// without pointers while waiting on additional runtime support (CL 698515).
  4071  			fn = ir.Syms.GrowsliceNoAlias
  4072  		}
  4073  		r = s.rtcall(fn, true, []*types.Type{n.Type()}, p, l, c, nargs, taddr)
  4074  	}
  4075  
  4076  	// Decompose output slice
  4077  	p = s.newValue1(ssa.OpSlicePtr, pt, r[0])
  4078  	l = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], r[0])
  4079  	c = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], r[0])
  4080  
  4081  	s.vars[ptrVar] = p
  4082  	s.vars[lenVar] = l
  4083  	s.vars[capVar] = c
  4084  	if inplace {
  4085  		if sn.Op() == ir.ONAME {
  4086  			sn := sn.(*ir.Name)
  4087  			if sn.Class != ir.PEXTERN {
  4088  				// Tell liveness we're about to build a new slice
  4089  				s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, sn, s.mem())
  4090  			}
  4091  		}
  4092  		capaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceCapOffset, addr)
  4093  		s.store(types.Types[types.TINT], capaddr, c)
  4094  		s.store(pt, addr, p)
  4095  	}
  4096  
  4097  	b = s.endBlock()
  4098  	b.AddEdgeTo(assign)
  4099  
  4100  	// assign new elements to slots
  4101  	s.startBlock(assign)
  4102  	p = s.variable(ptrVar, pt)                      // generates phi for ptr
  4103  	l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  4104  	if !inplace {
  4105  		c = s.variable(capVar, types.Types[types.TINT]) // generates phi for cap
  4106  	}
  4107  
  4108  	if inplace {
  4109  		// Update length in place.
  4110  		// We have to wait until here to make sure growslice succeeded.
  4111  		lenaddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, types.SliceLenOffset, addr)
  4112  		s.store(types.Types[types.TINT], lenaddr, l)
  4113  	}
  4114  
  4115  	// Evaluate args
  4116  	type argRec struct {
  4117  		// if store is true, we're appending the value v.  If false, we're appending the
  4118  		// value at *v.
  4119  		v     *ssa.Value
  4120  		store bool
  4121  	}
  4122  	args := make([]argRec, 0, len(n.Args[1:]))
  4123  	for _, n := range n.Args[1:] {
  4124  		if ssa.CanSSA(n.Type()) {
  4125  			args = append(args, argRec{v: s.expr(n), store: true})
  4126  		} else {
  4127  			v := s.addr(n)
  4128  			args = append(args, argRec{v: v})
  4129  		}
  4130  	}
  4131  
  4132  	// Write args into slice.
  4133  	oldLen = s.newValue2(s.ssaOp(ir.OSUB, types.Types[types.TINT]), types.Types[types.TINT], l, nargs)
  4134  	p2 := s.newValue2(ssa.OpPtrIndex, pt, p, oldLen)
  4135  	for i, arg := range args {
  4136  		addr := s.newValue2(ssa.OpPtrIndex, pt, p2, s.constInt(types.Types[types.TINT], int64(i)))
  4137  		if arg.store {
  4138  			s.storeType(et, addr, arg.v, 0, true)
  4139  		} else {
  4140  			s.move(et, addr, arg.v)
  4141  		}
  4142  	}
  4143  
  4144  	// The following deletions have no practical effect at this time
  4145  	// because state.vars has been reset by the preceding state.startBlock.
  4146  	// They only enforce the fact that these variables are no longer need in
  4147  	// the current scope.
  4148  	delete(s.vars, ptrVar)
  4149  	delete(s.vars, lenVar)
  4150  	if !inplace {
  4151  		delete(s.vars, capVar)
  4152  	}
  4153  
  4154  	// make result
  4155  	if inplace {
  4156  		return nil
  4157  	}
  4158  	return s.newValue3(ssa.OpSliceMake, n.Type(), p, l, c)
  4159  }
  4160  
  4161  func (s *state) move2heap(n *ir.MoveToHeapExpr) *ssa.Value {
  4162  	// s := n.Slice
  4163  	// if s.ptr points to current stack frame {
  4164  	//     s2 := make([]T, s.len, s.cap)
  4165  	//     copy(s2[:cap], s[:cap])
  4166  	//     s = s2
  4167  	// }
  4168  	// return s
  4169  
  4170  	slice := s.expr(n.Slice)
  4171  	et := slice.Type.Elem()
  4172  	pt := types.NewPtr(et)
  4173  
  4174  	info := s.getBackingStoreInfo(n)
  4175  	if info == nil {
  4176  		// Backing store will never be stack allocated, so
  4177  		// move2heap is a no-op.
  4178  		return slice
  4179  	}
  4180  
  4181  	// Decomposse input slice.
  4182  	p := s.newValue1(ssa.OpSlicePtr, pt, slice)
  4183  	l := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], slice)
  4184  	c := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], slice)
  4185  
  4186  	moveBlock := s.f.NewBlock(ssa.BlockPlain)
  4187  	mergeBlock := s.f.NewBlock(ssa.BlockPlain)
  4188  
  4189  	s.vars[ptrVar] = p
  4190  	s.vars[lenVar] = l
  4191  	s.vars[capVar] = c
  4192  
  4193  	// Decide if we need to move the slice backing store.
  4194  	// It needs to be moved if it is currently on the stack.
  4195  	sub := ssa.OpSub64
  4196  	less := ssa.OpLess64U
  4197  	if s.config.PtrSize == 4 {
  4198  		sub = ssa.OpSub32
  4199  		less = ssa.OpLess32U
  4200  	}
  4201  	callerSP := s.newValue1(ssa.OpGetCallerSP, types.Types[types.TUINTPTR], s.mem())
  4202  	frameSize := s.newValue2(sub, types.Types[types.TUINTPTR], callerSP, s.sp)
  4203  	pInt := s.newValue2(ssa.OpConvert, types.Types[types.TUINTPTR], p, s.mem())
  4204  	off := s.newValue2(sub, types.Types[types.TUINTPTR], pInt, s.sp)
  4205  	cond := s.newValue2(less, types.Types[types.TBOOL], off, frameSize)
  4206  
  4207  	b := s.endBlock()
  4208  	b.Kind = ssa.BlockIf
  4209  	b.Likely = ssa.BranchUnlikely // fast path is to not have to call into runtime
  4210  	b.SetControl(cond)
  4211  	b.AddEdgeTo(moveBlock)
  4212  	b.AddEdgeTo(mergeBlock)
  4213  
  4214  	// Move the slice to heap
  4215  	s.startBlock(moveBlock)
  4216  	var newSlice *ssa.Value
  4217  	if et.HasPointers() {
  4218  		typ := s.expr(n.RType)
  4219  		if n.PreserveCapacity {
  4220  			newSlice = s.rtcall(ir.Syms.MoveSlice, true, []*types.Type{slice.Type}, typ, p, l, c)[0]
  4221  		} else {
  4222  			newSlice = s.rtcall(ir.Syms.MoveSliceNoCap, true, []*types.Type{slice.Type}, typ, p, l)[0]
  4223  		}
  4224  	} else {
  4225  		elemSize := s.constInt(types.Types[types.TUINTPTR], et.Size())
  4226  		if n.PreserveCapacity {
  4227  			newSlice = s.rtcall(ir.Syms.MoveSliceNoScan, true, []*types.Type{slice.Type}, elemSize, p, l, c)[0]
  4228  		} else {
  4229  			newSlice = s.rtcall(ir.Syms.MoveSliceNoCapNoScan, true, []*types.Type{slice.Type}, elemSize, p, l)[0]
  4230  		}
  4231  	}
  4232  	// Decompose output slice
  4233  	s.vars[ptrVar] = s.newValue1(ssa.OpSlicePtr, pt, newSlice)
  4234  	s.vars[lenVar] = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], newSlice)
  4235  	s.vars[capVar] = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], newSlice)
  4236  	b = s.endBlock()
  4237  	b.AddEdgeTo(mergeBlock)
  4238  
  4239  	// Merge fast path (no moving) and slow path (moved)
  4240  	s.startBlock(mergeBlock)
  4241  	p = s.variable(ptrVar, pt)                      // generates phi for ptr
  4242  	l = s.variable(lenVar, types.Types[types.TINT]) // generates phi for len
  4243  	c = s.variable(capVar, types.Types[types.TINT]) // generates phi for cap
  4244  	delete(s.vars, ptrVar)
  4245  	delete(s.vars, lenVar)
  4246  	delete(s.vars, capVar)
  4247  	return s.newValue3(ssa.OpSliceMake, slice.Type, p, l, c)
  4248  }
  4249  
  4250  // minMax converts an OMIN/OMAX builtin call into SSA.
  4251  func (s *state) minMax(n *ir.CallExpr) *ssa.Value {
  4252  	// The OMIN/OMAX builtin is variadic, but its semantics are
  4253  	// equivalent to left-folding a binary min/max operation across the
  4254  	// arguments list.
  4255  	fold := func(op func(x, a *ssa.Value) *ssa.Value) *ssa.Value {
  4256  		x := s.expr(n.Args[0])
  4257  		for _, arg := range n.Args[1:] {
  4258  			x = op(x, s.expr(arg))
  4259  		}
  4260  		return x
  4261  	}
  4262  
  4263  	typ := n.Type()
  4264  
  4265  	if typ.IsFloat() || typ.IsString() {
  4266  		// min/max semantics for floats are tricky because of NaNs and
  4267  		// negative zero. Some architectures have instructions which
  4268  		// we can use to generate the right result. For others we must
  4269  		// call into the runtime instead.
  4270  		//
  4271  		// Strings are conceptually simpler, but we currently desugar
  4272  		// string comparisons during walk, not ssagen.
  4273  
  4274  		if typ.IsFloat() {
  4275  			hasIntrinsic := false
  4276  			switch Arch.LinkArch.Family {
  4277  			case sys.AMD64, sys.ARM64, sys.Loong64, sys.RISCV64, sys.S390X:
  4278  				hasIntrinsic = true
  4279  			case sys.PPC64:
  4280  				hasIntrinsic = buildcfg.GOPPC64 >= 9
  4281  			}
  4282  
  4283  			if hasIntrinsic {
  4284  				var op ssa.Op
  4285  				switch {
  4286  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMIN:
  4287  					op = ssa.OpMin64F
  4288  				case typ.Kind() == types.TFLOAT64 && n.Op() == ir.OMAX:
  4289  					op = ssa.OpMax64F
  4290  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMIN:
  4291  					op = ssa.OpMin32F
  4292  				case typ.Kind() == types.TFLOAT32 && n.Op() == ir.OMAX:
  4293  					op = ssa.OpMax32F
  4294  				}
  4295  				return fold(func(x, a *ssa.Value) *ssa.Value {
  4296  					return s.newValue2(op, typ, x, a)
  4297  				})
  4298  			}
  4299  		}
  4300  		var name string
  4301  		switch typ.Kind() {
  4302  		case types.TFLOAT32:
  4303  			switch n.Op() {
  4304  			case ir.OMIN:
  4305  				name = "fmin32"
  4306  			case ir.OMAX:
  4307  				name = "fmax32"
  4308  			}
  4309  		case types.TFLOAT64:
  4310  			switch n.Op() {
  4311  			case ir.OMIN:
  4312  				name = "fmin64"
  4313  			case ir.OMAX:
  4314  				name = "fmax64"
  4315  			}
  4316  		case types.TSTRING:
  4317  			switch n.Op() {
  4318  			case ir.OMIN:
  4319  				name = "strmin"
  4320  			case ir.OMAX:
  4321  				name = "strmax"
  4322  			}
  4323  		}
  4324  		fn := typecheck.LookupRuntimeFunc(name)
  4325  
  4326  		return fold(func(x, a *ssa.Value) *ssa.Value {
  4327  			return s.rtcall(fn, true, []*types.Type{typ}, x, a)[0]
  4328  		})
  4329  	}
  4330  
  4331  	if typ.IsInteger() {
  4332  		if Arch.LinkArch.Family == sys.RISCV64 && buildcfg.GORISCV64 >= 22 && typ.Size() == 8 {
  4333  			var op ssa.Op
  4334  			switch {
  4335  			case typ.IsSigned() && n.Op() == ir.OMIN:
  4336  				op = ssa.OpMin64
  4337  			case typ.IsSigned() && n.Op() == ir.OMAX:
  4338  				op = ssa.OpMax64
  4339  			case typ.IsUnsigned() && n.Op() == ir.OMIN:
  4340  				op = ssa.OpMin64u
  4341  			case typ.IsUnsigned() && n.Op() == ir.OMAX:
  4342  				op = ssa.OpMax64u
  4343  			}
  4344  			return fold(func(x, a *ssa.Value) *ssa.Value {
  4345  				return s.newValue2(op, typ, x, a)
  4346  			})
  4347  		}
  4348  	}
  4349  
  4350  	lt := s.ssaOp(ir.OLT, typ)
  4351  
  4352  	return fold(func(x, a *ssa.Value) *ssa.Value {
  4353  		switch n.Op() {
  4354  		case ir.OMIN:
  4355  			// a < x ? a : x
  4356  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], a, x), a, x)
  4357  		case ir.OMAX:
  4358  			// x < a ? a : x
  4359  			return s.ternary(s.newValue2(lt, types.Types[types.TBOOL], x, a), a, x)
  4360  		}
  4361  		panic("unreachable")
  4362  	})
  4363  }
  4364  
  4365  // ternary emits code to evaluate cond ? x : y.
  4366  func (s *state) ternary(cond, x, y *ssa.Value) *ssa.Value {
  4367  	// Note that we need a new ternaryVar each time (unlike okVar where we can
  4368  	// reuse the variable) because it might have a different type every time.
  4369  	ternaryVar := ssaMarker("ternary")
  4370  
  4371  	bThen := s.f.NewBlock(ssa.BlockPlain)
  4372  	bElse := s.f.NewBlock(ssa.BlockPlain)
  4373  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  4374  
  4375  	b := s.endBlock()
  4376  	b.Kind = ssa.BlockIf
  4377  	b.SetControl(cond)
  4378  	b.AddEdgeTo(bThen)
  4379  	b.AddEdgeTo(bElse)
  4380  
  4381  	s.startBlock(bThen)
  4382  	s.vars[ternaryVar] = x
  4383  	s.endBlock().AddEdgeTo(bEnd)
  4384  
  4385  	s.startBlock(bElse)
  4386  	s.vars[ternaryVar] = y
  4387  	s.endBlock().AddEdgeTo(bEnd)
  4388  
  4389  	s.startBlock(bEnd)
  4390  	r := s.variable(ternaryVar, x.Type)
  4391  	delete(s.vars, ternaryVar)
  4392  	return r
  4393  }
  4394  
  4395  // condBranch evaluates the boolean expression cond and branches to yes
  4396  // if cond is true and no if cond is false.
  4397  // This function is intended to handle && and || better than just calling
  4398  // s.expr(cond) and branching on the result.
  4399  func (s *state) condBranch(cond ir.Node, yes, no *ssa.Block, likely int8) {
  4400  	switch cond.Op() {
  4401  	case ir.OANDAND:
  4402  		cond := cond.(*ir.LogicalExpr)
  4403  		mid := s.f.NewBlock(ssa.BlockPlain)
  4404  		s.stmtList(cond.Init())
  4405  		s.condBranch(cond.X, mid, no, max(likely, 0))
  4406  		s.startBlock(mid)
  4407  		s.condBranch(cond.Y, yes, no, likely)
  4408  		return
  4409  		// Note: if likely==1, then both recursive calls pass 1.
  4410  		// If likely==-1, then we don't have enough information to decide
  4411  		// whether the first branch is likely or not. So we pass 0 for
  4412  		// the likeliness of the first branch.
  4413  		// TODO: have the frontend give us branch prediction hints for
  4414  		// OANDAND and OOROR nodes (if it ever has such info).
  4415  	case ir.OOROR:
  4416  		cond := cond.(*ir.LogicalExpr)
  4417  		mid := s.f.NewBlock(ssa.BlockPlain)
  4418  		s.stmtList(cond.Init())
  4419  		s.condBranch(cond.X, yes, mid, min(likely, 0))
  4420  		s.startBlock(mid)
  4421  		s.condBranch(cond.Y, yes, no, likely)
  4422  		return
  4423  		// Note: if likely==-1, then both recursive calls pass -1.
  4424  		// If likely==1, then we don't have enough info to decide
  4425  		// the likelihood of the first branch.
  4426  	case ir.ONOT:
  4427  		cond := cond.(*ir.UnaryExpr)
  4428  		s.stmtList(cond.Init())
  4429  		s.condBranch(cond.X, no, yes, -likely)
  4430  		return
  4431  	case ir.OCONVNOP:
  4432  		cond := cond.(*ir.ConvExpr)
  4433  		s.stmtList(cond.Init())
  4434  		s.condBranch(cond.X, yes, no, likely)
  4435  		return
  4436  	}
  4437  	c := s.expr(cond)
  4438  	b := s.endBlock()
  4439  	b.Kind = ssa.BlockIf
  4440  	b.SetControl(c)
  4441  	b.Likely = ssa.BranchPrediction(likely) // gc and ssa both use -1/0/+1 for likeliness
  4442  	b.AddEdgeTo(yes)
  4443  	b.AddEdgeTo(no)
  4444  }
  4445  
  4446  type skipMask uint8
  4447  
  4448  const (
  4449  	skipPtr skipMask = 1 << iota
  4450  	skipLen
  4451  	skipCap
  4452  )
  4453  
  4454  // assign does left = right.
  4455  // Right has already been evaluated to ssa, left has not.
  4456  // If deref is true, then we do left = *right instead (and right has already been nil-checked).
  4457  // If deref is true and right == nil, just do left = 0.
  4458  // skip indicates assignments (at the top level) that can be avoided.
  4459  // mayOverlap indicates whether left&right might partially overlap in memory. Default is false.
  4460  func (s *state) assign(left ir.Node, right *ssa.Value, deref bool, skip skipMask) {
  4461  	s.assignWhichMayOverlap(left, right, deref, skip, false)
  4462  }
  4463  func (s *state) assignWhichMayOverlap(left ir.Node, right *ssa.Value, deref bool, skip skipMask, mayOverlap bool) {
  4464  	if left.Op() == ir.ONAME && ir.IsBlank(left) {
  4465  		return
  4466  	}
  4467  	t := left.Type()
  4468  	types.CalcSize(t)
  4469  	if s.canSSA(left) {
  4470  		if deref {
  4471  			s.Fatalf("can SSA LHS %v but not RHS %s", left, right)
  4472  		}
  4473  		if left.Op() == ir.ODOT {
  4474  			// We're assigning to a field of an ssa-able value.
  4475  			// We need to build a new structure with the new value for the
  4476  			// field we're assigning and the old values for the other fields.
  4477  			// For instance:
  4478  			//   type T struct {a, b, c int}
  4479  			//   var T x
  4480  			//   x.b = 5
  4481  			// For the x.b = 5 assignment we want to generate x = T{x.a, 5, x.c}
  4482  
  4483  			// Grab information about the structure type.
  4484  			left := left.(*ir.SelectorExpr)
  4485  			t := left.X.Type()
  4486  			nf := t.NumFields()
  4487  			idx := fieldIdx(left)
  4488  
  4489  			// Grab old value of structure.
  4490  			old := s.expr(left.X)
  4491  
  4492  			if left.Type().Size() == 0 {
  4493  				// Nothing to do when assigning zero-sized things.
  4494  				return
  4495  			}
  4496  
  4497  			// Make new structure.
  4498  			new := s.newValue0(ssa.OpStructMake, t)
  4499  
  4500  			// Add fields as args.
  4501  			for i := 0; i < nf; i++ {
  4502  				if i == idx {
  4503  					new.AddArg(right)
  4504  				} else {
  4505  					new.AddArg(s.newValue1I(ssa.OpStructSelect, t.FieldType(i), int64(i), old))
  4506  				}
  4507  			}
  4508  
  4509  			// Recursively assign the new value we've made to the base of the dot op.
  4510  			s.assign(left.X, new, false, 0)
  4511  			// TODO: do we need to update named values here?
  4512  			return
  4513  		}
  4514  		if left.Op() == ir.OINDEX && left.(*ir.IndexExpr).X.Type().IsArray() {
  4515  			left := left.(*ir.IndexExpr)
  4516  			s.pushLine(left.Pos())
  4517  			defer s.popLine()
  4518  			// We're assigning to an element of an ssa-able array.
  4519  			// a[i] = v
  4520  			t := left.X.Type()
  4521  			n := t.NumElem()
  4522  
  4523  			i := s.expr(left.Index) // index
  4524  			if n == 0 {
  4525  				// The bounds check must fail.  Might as well
  4526  				// ignore the actual index and just use zeros.
  4527  				z := s.constInt(types.Types[types.TINT], 0)
  4528  				s.boundsCheck(z, z, ssa.BoundsIndex, false)
  4529  				return
  4530  			}
  4531  			if n != 1 {
  4532  				// This can happen in weird, always-panics cases, like:
  4533  				//     var x [0][2]int
  4534  				//     x[i][j] = 5
  4535  				// We know it always panics because the LHS is ssa-able,
  4536  				// and arrays of length > 1 can't be ssa-able unless
  4537  				// they are somewhere inside an outer [0].
  4538  				// We can ignore the actual assignment, it is dynamically
  4539  				// unreachable. See issue 77635.
  4540  				return
  4541  			}
  4542  			if t.Size() == 0 {
  4543  				return
  4544  			}
  4545  
  4546  			// Rewrite to a = [1]{v}
  4547  			len := s.constInt(types.Types[types.TINT], 1)
  4548  			s.boundsCheck(i, len, ssa.BoundsIndex, false) // checks i == 0
  4549  			v := s.newValue1(ssa.OpArrayMake1, t, right)
  4550  			s.assign(left.X, v, false, 0)
  4551  			return
  4552  		}
  4553  		left := left.(*ir.Name)
  4554  		// Update variable assignment.
  4555  		s.vars[left] = right
  4556  		s.addNamedValue(left, right)
  4557  		return
  4558  	}
  4559  
  4560  	// If this assignment clobbers an entire local variable, then emit
  4561  	// OpVarDef so liveness analysis knows the variable is redefined.
  4562  	if base, ok := clobberBase(left).(*ir.Name); ok && base.OnStack() && skip == 0 && (t.HasPointers() || ssa.IsMergeCandidate(base)) {
  4563  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, base, s.mem(), !ir.IsAutoTmp(base))
  4564  	}
  4565  
  4566  	// Left is not ssa-able. Compute its address.
  4567  	addr := s.addr(left)
  4568  	if ir.IsReflectHeaderDataField(left) {
  4569  		// Package unsafe's documentation says storing pointers into
  4570  		// reflect.SliceHeader and reflect.StringHeader's Data fields
  4571  		// is valid, even though they have type uintptr (#19168).
  4572  		// Mark it pointer type to signal the writebarrier pass to
  4573  		// insert a write barrier.
  4574  		t = types.Types[types.TUNSAFEPTR]
  4575  	}
  4576  	if deref {
  4577  		// Treat as a mem->mem move.
  4578  		if right == nil {
  4579  			s.zero(t, addr)
  4580  		} else {
  4581  			s.moveWhichMayOverlap(t, addr, right, mayOverlap)
  4582  		}
  4583  		return
  4584  	}
  4585  	// Treat as a store.
  4586  	s.storeType(t, addr, right, skip, !ir.IsAutoTmp(left))
  4587  }
  4588  
  4589  // zeroVal returns the zero value for type t.
  4590  func (s *state) zeroVal(t *types.Type) *ssa.Value {
  4591  	if t.Size() == 0 {
  4592  		return s.entryNewValue0(ssa.OpEmpty, t)
  4593  	}
  4594  	switch {
  4595  	case t.IsInteger():
  4596  		switch t.Size() {
  4597  		case 1:
  4598  			return s.constInt8(t, 0)
  4599  		case 2:
  4600  			return s.constInt16(t, 0)
  4601  		case 4:
  4602  			return s.constInt32(t, 0)
  4603  		case 8:
  4604  			return s.constInt64(t, 0)
  4605  		default:
  4606  			s.Fatalf("bad sized integer type %v", t)
  4607  		}
  4608  	case t.IsFloat():
  4609  		switch t.Size() {
  4610  		case 4:
  4611  			return s.constFloat32(t, 0)
  4612  		case 8:
  4613  			return s.constFloat64(t, 0)
  4614  		default:
  4615  			s.Fatalf("bad sized float type %v", t)
  4616  		}
  4617  	case t.IsComplex():
  4618  		switch t.Size() {
  4619  		case 8:
  4620  			z := s.constFloat32(types.Types[types.TFLOAT32], 0)
  4621  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4622  		case 16:
  4623  			z := s.constFloat64(types.Types[types.TFLOAT64], 0)
  4624  			return s.entryNewValue2(ssa.OpComplexMake, t, z, z)
  4625  		default:
  4626  			s.Fatalf("bad sized complex type %v", t)
  4627  		}
  4628  
  4629  	case t.IsString():
  4630  		return s.constEmptyString(t)
  4631  	case t.IsPtrShaped():
  4632  		return s.constNil(t)
  4633  	case t.IsBoolean():
  4634  		return s.constBool(false)
  4635  	case t.IsInterface():
  4636  		return s.constInterface(t)
  4637  	case t.IsSlice():
  4638  		return s.constSlice(t)
  4639  	case isStructNotSIMD(t):
  4640  		n := t.NumFields()
  4641  		v := s.entryNewValue0(ssa.OpStructMake, t)
  4642  		for i := 0; i < n; i++ {
  4643  			v.AddArg(s.zeroVal(t.FieldType(i)))
  4644  		}
  4645  		return v
  4646  	case t.IsArray() && t.NumElem() == 1:
  4647  		return s.entryNewValue1(ssa.OpArrayMake1, t, s.zeroVal(t.Elem()))
  4648  	case t.IsSIMD():
  4649  		return s.newValue0(ssa.OpZeroSIMD, t)
  4650  	}
  4651  	s.Fatalf("zero for type %v not implemented", t)
  4652  	return nil
  4653  }
  4654  
  4655  type callKind int8
  4656  
  4657  const (
  4658  	callNormal callKind = iota
  4659  	callDefer
  4660  	callDeferStack
  4661  	callGo
  4662  	callTail
  4663  )
  4664  
  4665  type sfRtCallDef struct {
  4666  	rtfn  *obj.LSym
  4667  	rtype types.Kind
  4668  }
  4669  
  4670  var softFloatOps map[ssa.Op]sfRtCallDef
  4671  
  4672  func softfloatInit() {
  4673  	// Some of these operations get transformed by sfcall.
  4674  	softFloatOps = map[ssa.Op]sfRtCallDef{
  4675  		ssa.OpAdd32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4676  		ssa.OpAdd64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4677  		ssa.OpSub32F: {typecheck.LookupRuntimeFunc("fadd32"), types.TFLOAT32},
  4678  		ssa.OpSub64F: {typecheck.LookupRuntimeFunc("fadd64"), types.TFLOAT64},
  4679  		ssa.OpMul32F: {typecheck.LookupRuntimeFunc("fmul32"), types.TFLOAT32},
  4680  		ssa.OpMul64F: {typecheck.LookupRuntimeFunc("fmul64"), types.TFLOAT64},
  4681  		ssa.OpDiv32F: {typecheck.LookupRuntimeFunc("fdiv32"), types.TFLOAT32},
  4682  		ssa.OpDiv64F: {typecheck.LookupRuntimeFunc("fdiv64"), types.TFLOAT64},
  4683  
  4684  		ssa.OpEq64F:   {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4685  		ssa.OpEq32F:   {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4686  		ssa.OpNeq64F:  {typecheck.LookupRuntimeFunc("feq64"), types.TBOOL},
  4687  		ssa.OpNeq32F:  {typecheck.LookupRuntimeFunc("feq32"), types.TBOOL},
  4688  		ssa.OpLess64F: {typecheck.LookupRuntimeFunc("fgt64"), types.TBOOL},
  4689  		ssa.OpLess32F: {typecheck.LookupRuntimeFunc("fgt32"), types.TBOOL},
  4690  		ssa.OpLeq64F:  {typecheck.LookupRuntimeFunc("fge64"), types.TBOOL},
  4691  		ssa.OpLeq32F:  {typecheck.LookupRuntimeFunc("fge32"), types.TBOOL},
  4692  
  4693  		ssa.OpCvt32to32F:  {typecheck.LookupRuntimeFunc("fint32to32"), types.TFLOAT32},
  4694  		ssa.OpCvt32Fto32:  {typecheck.LookupRuntimeFunc("f32toint32"), types.TINT32},
  4695  		ssa.OpCvt64to32F:  {typecheck.LookupRuntimeFunc("fint64to32"), types.TFLOAT32},
  4696  		ssa.OpCvt32Fto64:  {typecheck.LookupRuntimeFunc("f32toint64"), types.TINT64},
  4697  		ssa.OpCvt64Uto32F: {typecheck.LookupRuntimeFunc("fuint64to32"), types.TFLOAT32},
  4698  		ssa.OpCvt32Fto64U: {typecheck.LookupRuntimeFunc("f32touint64"), types.TUINT64},
  4699  		ssa.OpCvt32to64F:  {typecheck.LookupRuntimeFunc("fint32to64"), types.TFLOAT64},
  4700  		ssa.OpCvt64Fto32:  {typecheck.LookupRuntimeFunc("f64toint32"), types.TINT32},
  4701  		ssa.OpCvt64to64F:  {typecheck.LookupRuntimeFunc("fint64to64"), types.TFLOAT64},
  4702  		ssa.OpCvt64Fto64:  {typecheck.LookupRuntimeFunc("f64toint64"), types.TINT64},
  4703  		ssa.OpCvt64Uto64F: {typecheck.LookupRuntimeFunc("fuint64to64"), types.TFLOAT64},
  4704  		ssa.OpCvt64Fto64U: {typecheck.LookupRuntimeFunc("f64touint64"), types.TUINT64},
  4705  		ssa.OpCvt32Fto64F: {typecheck.LookupRuntimeFunc("f32to64"), types.TFLOAT64},
  4706  		ssa.OpCvt64Fto32F: {typecheck.LookupRuntimeFunc("f64to32"), types.TFLOAT32},
  4707  	}
  4708  }
  4709  
  4710  // TODO: do not emit sfcall if operation can be optimized to constant in later
  4711  // opt phase
  4712  func (s *state) sfcall(op ssa.Op, args ...*ssa.Value) (*ssa.Value, bool) {
  4713  	f2i := func(t *types.Type) *types.Type {
  4714  		switch t.Kind() {
  4715  		case types.TFLOAT32:
  4716  			return types.Types[types.TUINT32]
  4717  		case types.TFLOAT64:
  4718  			return types.Types[types.TUINT64]
  4719  		}
  4720  		return t
  4721  	}
  4722  
  4723  	if callDef, ok := softFloatOps[op]; ok {
  4724  		switch op {
  4725  		case ssa.OpLess32F,
  4726  			ssa.OpLess64F,
  4727  			ssa.OpLeq32F,
  4728  			ssa.OpLeq64F:
  4729  			args[0], args[1] = args[1], args[0]
  4730  		case ssa.OpSub32F,
  4731  			ssa.OpSub64F:
  4732  			args[1] = s.newValue1(s.ssaOp(ir.ONEG, types.Types[callDef.rtype]), args[1].Type, args[1])
  4733  		}
  4734  
  4735  		// runtime functions take uints for floats and returns uints.
  4736  		// Convert to uints so we use the right calling convention.
  4737  		for i, a := range args {
  4738  			if a.Type.IsFloat() {
  4739  				args[i] = s.newValue1(ssa.OpCopy, f2i(a.Type), a)
  4740  			}
  4741  		}
  4742  
  4743  		rt := types.Types[callDef.rtype]
  4744  		result := s.rtcall(callDef.rtfn, true, []*types.Type{f2i(rt)}, args...)[0]
  4745  		if rt.IsFloat() {
  4746  			result = s.newValue1(ssa.OpCopy, rt, result)
  4747  		}
  4748  		if op == ssa.OpNeq32F || op == ssa.OpNeq64F {
  4749  			result = s.newValue1(ssa.OpNot, result.Type, result)
  4750  		}
  4751  		return result, true
  4752  	}
  4753  	return nil, false
  4754  }
  4755  
  4756  // split breaks up a tuple-typed value into its 2 parts.
  4757  func (s *state) split(v *ssa.Value) (*ssa.Value, *ssa.Value) {
  4758  	p0 := s.newValue1(ssa.OpSelect0, v.Type.FieldType(0), v)
  4759  	p1 := s.newValue1(ssa.OpSelect1, v.Type.FieldType(1), v)
  4760  	return p0, p1
  4761  }
  4762  
  4763  // intrinsicCall converts a call to a recognized intrinsic function into the intrinsic SSA operation.
  4764  func (s *state) intrinsicCall(n *ir.CallExpr) *ssa.Value {
  4765  	v := findIntrinsic(n.Fun.Sym())(s, n, s.intrinsicArgs(n))
  4766  	if ssa.IntrinsicsDebug > 0 {
  4767  		x := v
  4768  		if x == nil {
  4769  			x = s.mem()
  4770  		}
  4771  		if x.Op == ssa.OpSelect0 || x.Op == ssa.OpSelect1 {
  4772  			x = x.Args[0]
  4773  		}
  4774  		base.WarnfAt(n.Pos(), "intrinsic substitution for %v with %s", n.Fun.Sym().Name, x.LongString())
  4775  	}
  4776  	return v
  4777  }
  4778  
  4779  // intrinsicArgs extracts args from n, evaluates them to SSA values, and returns them.
  4780  func (s *state) intrinsicArgs(n *ir.CallExpr) []*ssa.Value {
  4781  	args := make([]*ssa.Value, len(n.Args))
  4782  	for i, n := range n.Args {
  4783  		args[i] = s.expr(n)
  4784  	}
  4785  	return args
  4786  }
  4787  
  4788  // openDeferRecord adds code to evaluate and store the function for an open-code defer
  4789  // call, and records info about the defer, so we can generate proper code on the
  4790  // exit paths. n is the sub-node of the defer node that is the actual function
  4791  // call. We will also record funcdata information on where the function is stored
  4792  // (as well as the deferBits variable), and this will enable us to run the proper
  4793  // defer calls during panics.
  4794  func (s *state) openDeferRecord(n *ir.CallExpr) {
  4795  	if len(n.Args) != 0 || n.Op() != ir.OCALLFUNC || n.Fun.Type().NumResults() != 0 {
  4796  		s.Fatalf("defer call with arguments or results: %v", n)
  4797  	}
  4798  
  4799  	opendefer := &openDeferInfo{
  4800  		n: n,
  4801  	}
  4802  	fn := n.Fun
  4803  	// We must always store the function value in a stack slot for the
  4804  	// runtime panic code to use. But in the defer exit code, we will
  4805  	// call the function directly if it is a static function.
  4806  	closureVal := s.expr(fn)
  4807  	closure := s.openDeferSave(fn.Type(), closureVal)
  4808  	opendefer.closureNode = closure.Aux.(*ir.Name)
  4809  	if !(fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC) {
  4810  		opendefer.closure = closure
  4811  	}
  4812  	index := len(s.openDefers)
  4813  	s.openDefers = append(s.openDefers, opendefer)
  4814  
  4815  	// Update deferBits only after evaluation and storage to stack of
  4816  	// the function is successful.
  4817  	bitvalue := s.constInt8(types.Types[types.TUINT8], 1<<uint(index))
  4818  	newDeferBits := s.newValue2(ssa.OpOr8, types.Types[types.TUINT8], s.variable(deferBitsVar, types.Types[types.TUINT8]), bitvalue)
  4819  	s.vars[deferBitsVar] = newDeferBits
  4820  	s.store(types.Types[types.TUINT8], s.deferBitsAddr, newDeferBits)
  4821  }
  4822  
  4823  // openDeferSave generates SSA nodes to store a value (with type t) for an
  4824  // open-coded defer at an explicit autotmp location on the stack, so it can be
  4825  // reloaded and used for the appropriate call on exit. Type t must be a function type
  4826  // (therefore SSAable). val is the value to be stored. The function returns an SSA
  4827  // value representing a pointer to the autotmp location.
  4828  func (s *state) openDeferSave(t *types.Type, val *ssa.Value) *ssa.Value {
  4829  	if !ssa.CanSSA(t) {
  4830  		s.Fatalf("openDeferSave of non-SSA-able type %v val=%v", t, val)
  4831  	}
  4832  	if !t.HasPointers() {
  4833  		s.Fatalf("openDeferSave of pointerless type %v val=%v", t, val)
  4834  	}
  4835  	pos := val.Pos
  4836  	temp := typecheck.TempAt(pos.WithNotStmt(), s.curfn, t)
  4837  	temp.SetOpenDeferSlot(true)
  4838  	temp.SetFrameOffset(int64(len(s.openDefers))) // so cmpstackvarlt can order them
  4839  	var addrTemp *ssa.Value
  4840  	// Use OpVarLive to make sure stack slot for the closure is not removed by
  4841  	// dead-store elimination
  4842  	if s.curBlock.ID != s.f.Entry.ID {
  4843  		// Force the tmp storing this defer function to be declared in the entry
  4844  		// block, so that it will be live for the defer exit code (which will
  4845  		// actually access it only if the associated defer call has been activated).
  4846  		if t.HasPointers() {
  4847  			s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarDef, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4848  		}
  4849  		s.defvars[s.f.Entry.ID][memVar] = s.f.Entry.NewValue1A(src.NoXPos, ssa.OpVarLive, types.TypeMem, temp, s.defvars[s.f.Entry.ID][memVar])
  4850  		addrTemp = s.f.Entry.NewValue2A(src.NoXPos, ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.defvars[s.f.Entry.ID][memVar])
  4851  	} else {
  4852  		// Special case if we're still in the entry block. We can't use
  4853  		// the above code, since s.defvars[s.f.Entry.ID] isn't defined
  4854  		// until we end the entry block with s.endBlock().
  4855  		if t.HasPointers() {
  4856  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarDef, types.TypeMem, temp, s.mem(), false)
  4857  		}
  4858  		s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, temp, s.mem(), false)
  4859  		addrTemp = s.newValue2Apos(ssa.OpLocalAddr, types.NewPtr(temp.Type()), temp, s.sp, s.mem(), false)
  4860  	}
  4861  	// Since we may use this temp during exit depending on the
  4862  	// deferBits, we must define it unconditionally on entry.
  4863  	// Therefore, we must make sure it is zeroed out in the entry
  4864  	// block if it contains pointers, else GC may wrongly follow an
  4865  	// uninitialized pointer value.
  4866  	temp.SetNeedzero(true)
  4867  	// We are storing to the stack, hence we can avoid the full checks in
  4868  	// storeType() (no write barrier) and do a simple store().
  4869  	s.store(t, addrTemp, val)
  4870  	return addrTemp
  4871  }
  4872  
  4873  // openDeferExit generates SSA for processing all the open coded defers at exit.
  4874  // The code involves loading deferBits, and checking each of the bits to see if
  4875  // the corresponding defer statement was executed. For each bit that is turned
  4876  // on, the associated defer call is made.
  4877  func (s *state) openDeferExit() {
  4878  	deferExit := s.f.NewBlock(ssa.BlockPlain)
  4879  	s.endBlock().AddEdgeTo(deferExit)
  4880  	s.startBlock(deferExit)
  4881  	s.lastDeferExit = deferExit
  4882  	s.lastDeferCount = len(s.openDefers)
  4883  	zeroval := s.constInt8(types.Types[types.TUINT8], 0)
  4884  	// Test for and run defers in reverse order
  4885  	for i := len(s.openDefers) - 1; i >= 0; i-- {
  4886  		r := s.openDefers[i]
  4887  		bCond := s.f.NewBlock(ssa.BlockPlain)
  4888  		bEnd := s.f.NewBlock(ssa.BlockPlain)
  4889  
  4890  		deferBits := s.variable(deferBitsVar, types.Types[types.TUINT8])
  4891  		// Generate code to check if the bit associated with the current
  4892  		// defer is set.
  4893  		bitval := s.constInt8(types.Types[types.TUINT8], 1<<uint(i))
  4894  		andval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, bitval)
  4895  		eqVal := s.newValue2(ssa.OpEq8, types.Types[types.TBOOL], andval, zeroval)
  4896  		b := s.endBlock()
  4897  		b.Kind = ssa.BlockIf
  4898  		b.SetControl(eqVal)
  4899  		b.AddEdgeTo(bEnd)
  4900  		b.AddEdgeTo(bCond)
  4901  		bCond.AddEdgeTo(bEnd)
  4902  		s.startBlock(bCond)
  4903  
  4904  		// Clear this bit in deferBits and force store back to stack, so
  4905  		// we will not try to re-run this defer call if this defer call panics.
  4906  		nbitval := s.newValue1(ssa.OpCom8, types.Types[types.TUINT8], bitval)
  4907  		maskedval := s.newValue2(ssa.OpAnd8, types.Types[types.TUINT8], deferBits, nbitval)
  4908  		s.store(types.Types[types.TUINT8], s.deferBitsAddr, maskedval)
  4909  		// Use this value for following tests, so we keep previous
  4910  		// bits cleared.
  4911  		s.vars[deferBitsVar] = maskedval
  4912  
  4913  		// Generate code to call the function call of the defer, using the
  4914  		// closure that were stored in argtmps at the point of the defer
  4915  		// statement.
  4916  		fn := r.n.Fun
  4917  		stksize := fn.Type().ArgWidth()
  4918  		var callArgs []*ssa.Value
  4919  		var call *ssa.Value
  4920  		if r.closure != nil {
  4921  			v := s.load(r.closure.Type.Elem(), r.closure)
  4922  			s.maybeNilCheckClosure(v, callDefer)
  4923  			codeptr := s.rawLoad(types.Types[types.TUINTPTR], v)
  4924  			aux := ssa.ClosureAuxCall(s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  4925  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, v)
  4926  		} else {
  4927  			aux := ssa.StaticAuxCall(fn.(*ir.Name).Linksym(), s.f.ABIDefault.ABIAnalyzeTypes(nil, nil))
  4928  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  4929  		}
  4930  		callArgs = append(callArgs, s.mem())
  4931  		call.AddArgs(callArgs...)
  4932  		call.AuxInt = stksize
  4933  		s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, 0, call)
  4934  		// Make sure that the stack slots with pointers are kept live
  4935  		// through the call (which is a pre-emption point). Also, we will
  4936  		// use the first call of the last defer exit to compute liveness
  4937  		// for the deferreturn, so we want all stack slots to be live.
  4938  		if r.closureNode != nil {
  4939  			s.vars[memVar] = s.newValue1Apos(ssa.OpVarLive, types.TypeMem, r.closureNode, s.mem(), false)
  4940  		}
  4941  
  4942  		s.endBlock()
  4943  		s.startBlock(bEnd)
  4944  	}
  4945  }
  4946  
  4947  func (s *state) callResult(n *ir.CallExpr, k callKind) *ssa.Value {
  4948  	return s.call(n, k, false, nil)
  4949  }
  4950  
  4951  func (s *state) callAddr(n *ir.CallExpr, k callKind) *ssa.Value {
  4952  	return s.call(n, k, true, nil)
  4953  }
  4954  
  4955  // Calls the function n using the specified call type.
  4956  // Returns the address of the return value (or nil if none).
  4957  func (s *state) call(n *ir.CallExpr, k callKind, returnResultAddr bool, deferExtra ir.Expr) *ssa.Value {
  4958  	s.prevCall = nil
  4959  	var calleeLSym *obj.LSym // target function (if static)
  4960  	var closure *ssa.Value   // ptr to closure to run (if dynamic)
  4961  	var codeptr *ssa.Value   // ptr to target code (if dynamic)
  4962  	var dextra *ssa.Value    // defer extra arg
  4963  	var rcvr *ssa.Value      // receiver to set
  4964  	fn := n.Fun
  4965  	var ACArgs []*types.Type    // AuxCall args
  4966  	var ACResults []*types.Type // AuxCall results
  4967  	var callArgs []*ssa.Value   // For late-expansion, the args themselves (not stored, args to the call instead).
  4968  
  4969  	callABI := s.f.ABIDefault
  4970  
  4971  	if k != callNormal && k != callTail && (len(n.Args) != 0 || n.Op() == ir.OCALLINTER || n.Fun.Type().NumResults() != 0) {
  4972  		s.Fatalf("go/defer call with arguments: %v", n)
  4973  	}
  4974  
  4975  	isCallDeferRangeFunc := false
  4976  
  4977  	switch n.Op() {
  4978  	case ir.OCALLFUNC:
  4979  		if (k == callNormal || k == callTail) && fn.Op() == ir.ONAME && fn.(*ir.Name).Class == ir.PFUNC {
  4980  			fn := fn.(*ir.Name)
  4981  			calleeLSym = callTargetLSym(fn)
  4982  			if buildcfg.Experiment.RegabiArgs {
  4983  				// This is a static call, so it may be
  4984  				// a direct call to a non-ABIInternal
  4985  				// function. fn.Func may be nil for
  4986  				// some compiler-generated functions,
  4987  				// but those are all ABIInternal.
  4988  				if fn.Func != nil {
  4989  					callABI = abiForFunc(fn.Func, s.f.ABI0, s.f.ABI1)
  4990  				}
  4991  			} else {
  4992  				// TODO(register args) remove after register abi is working
  4993  				inRegistersImported := fn.Pragma()&ir.RegisterParams != 0
  4994  				inRegistersSamePackage := fn.Func != nil && fn.Func.Pragma&ir.RegisterParams != 0
  4995  				if inRegistersImported || inRegistersSamePackage {
  4996  					callABI = s.f.ABI1
  4997  				}
  4998  			}
  4999  			if fn := n.Fun.Sym().Name; n.Fun.Sym().Pkg == ir.Pkgs.Runtime && fn == "deferrangefunc" {
  5000  				isCallDeferRangeFunc = true
  5001  			}
  5002  			break
  5003  		}
  5004  		closure = s.expr(fn)
  5005  		if k != callDefer && k != callDeferStack {
  5006  			// Deferred nil function needs to panic when the function is invoked,
  5007  			// not the point of defer statement.
  5008  			s.maybeNilCheckClosure(closure, k)
  5009  		}
  5010  	case ir.OCALLINTER:
  5011  		if fn.Op() != ir.ODOTINTER {
  5012  			s.Fatalf("OCALLINTER: n.Left not an ODOTINTER: %v", fn.Op())
  5013  		}
  5014  		fn := fn.(*ir.SelectorExpr)
  5015  		var iclosure *ssa.Value
  5016  		iclosure, rcvr = s.getClosureAndRcvr(fn)
  5017  		if k == callNormal || k == callTail {
  5018  			codeptr = s.load(types.Types[types.TUINTPTR], iclosure)
  5019  		} else {
  5020  			closure = iclosure
  5021  		}
  5022  	}
  5023  	if deferExtra != nil {
  5024  		dextra = s.expr(deferExtra)
  5025  	}
  5026  
  5027  	params := callABI.ABIAnalyze(n.Fun.Type(), false /* Do not set (register) nNames from caller side -- can cause races. */)
  5028  	types.CalcSize(fn.Type())
  5029  	stksize := params.ArgWidth() // includes receiver, args, and results
  5030  
  5031  	res := n.Fun.Type().Results()
  5032  	if k == callNormal || k == callTail {
  5033  		for _, p := range params.OutParams() {
  5034  			ACResults = append(ACResults, p.Type)
  5035  		}
  5036  	}
  5037  
  5038  	var call *ssa.Value
  5039  	if k == callDeferStack {
  5040  		if stksize != 0 {
  5041  			s.Fatalf("deferprocStack with non-zero stack size %d: %v", stksize, n)
  5042  		}
  5043  		// Make a defer struct on the stack.
  5044  		t := deferstruct()
  5045  		n, addr := s.temp(n.Pos(), t)
  5046  		n.SetNonMergeable(true)
  5047  		s.store(closure.Type,
  5048  			s.newValue1I(ssa.OpOffPtr, closure.Type.PtrTo(), t.FieldOff(deferStructFnField), addr),
  5049  			closure)
  5050  
  5051  		// Call runtime.deferprocStack with pointer to _defer record.
  5052  		ACArgs = append(ACArgs, types.Types[types.TUINTPTR])
  5053  		aux := ssa.StaticAuxCall(ir.Syms.DeferprocStack, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  5054  		callArgs = append(callArgs, addr, s.mem())
  5055  		call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5056  		call.AddArgs(callArgs...)
  5057  		call.AuxInt = int64(types.PtrSize) // deferprocStack takes a *_defer arg
  5058  	} else {
  5059  		// Store arguments to stack, including defer/go arguments and receiver for method calls.
  5060  		// These are written in SP-offset order.
  5061  		argStart := base.Ctxt.Arch.FixedFrameSize
  5062  		// Defer/go args.
  5063  		if k != callNormal && k != callTail {
  5064  			// Write closure (arg to newproc/deferproc).
  5065  			ACArgs = append(ACArgs, types.Types[types.TUINTPTR]) // not argExtra
  5066  			callArgs = append(callArgs, closure)
  5067  			stksize += int64(types.PtrSize)
  5068  			argStart += int64(types.PtrSize)
  5069  			if dextra != nil {
  5070  				// Extra token of type any for deferproc
  5071  				ACArgs = append(ACArgs, types.Types[types.TINTER])
  5072  				callArgs = append(callArgs, dextra)
  5073  				stksize += 2 * int64(types.PtrSize)
  5074  				argStart += 2 * int64(types.PtrSize)
  5075  			}
  5076  		}
  5077  
  5078  		// Set receiver (for interface calls).
  5079  		if rcvr != nil {
  5080  			callArgs = append(callArgs, rcvr)
  5081  		}
  5082  
  5083  		// Write args.
  5084  		t := n.Fun.Type()
  5085  		args := n.Args
  5086  
  5087  		for _, p := range params.InParams() { // includes receiver for interface calls
  5088  			ACArgs = append(ACArgs, p.Type)
  5089  		}
  5090  
  5091  		// Split the entry block if there are open defers, because later calls to
  5092  		// openDeferSave may cause a mismatch between the mem for an OpDereference
  5093  		// and the call site which uses it. See #49282.
  5094  		if s.curBlock.ID == s.f.Entry.ID && s.hasOpenDefers {
  5095  			b := s.endBlock()
  5096  			b.Kind = ssa.BlockPlain
  5097  			curb := s.f.NewBlock(ssa.BlockPlain)
  5098  			b.AddEdgeTo(curb)
  5099  			s.startBlock(curb)
  5100  		}
  5101  
  5102  		for i, n := range args {
  5103  			callArgs = append(callArgs, s.putArg(n, t.Param(i).Type))
  5104  		}
  5105  
  5106  		callArgs = append(callArgs, s.mem())
  5107  
  5108  		// call target
  5109  		switch {
  5110  		case k == callDefer:
  5111  			sym := ir.Syms.Deferproc
  5112  			if dextra != nil {
  5113  				sym = ir.Syms.Deferprocat
  5114  			}
  5115  			aux := ssa.StaticAuxCall(sym, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults)) // TODO paramResultInfo for Deferproc(at)
  5116  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5117  		case k == callGo:
  5118  			aux := ssa.StaticAuxCall(ir.Syms.Newproc, s.f.ABIDefault.ABIAnalyzeTypes(ACArgs, ACResults))
  5119  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux) // TODO paramResultInfo for Newproc
  5120  		case closure != nil:
  5121  			// rawLoad because loading the code pointer from a
  5122  			// closure is always safe, but IsSanitizerSafeAddr
  5123  			// can't always figure that out currently, and it's
  5124  			// critical that we not clobber any arguments already
  5125  			// stored onto the stack.
  5126  			codeptr = s.rawLoad(types.Types[types.TUINTPTR], closure)
  5127  			aux := ssa.ClosureAuxCall(callABI.ABIAnalyzeTypes(ACArgs, ACResults))
  5128  			call = s.newValue2A(ssa.OpClosureLECall, aux.LateExpansionResultType(), aux, codeptr, closure)
  5129  		case codeptr != nil:
  5130  			// Note that the "receiver" parameter is nil because the actual receiver is the first input parameter.
  5131  			aux := ssa.InterfaceAuxCall(params)
  5132  			call = s.newValue1A(ssa.OpInterLECall, aux.LateExpansionResultType(), aux, codeptr)
  5133  			if k == callTail {
  5134  				call.Op = ssa.OpTailLECallInter
  5135  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  5136  			}
  5137  		case calleeLSym != nil:
  5138  			aux := ssa.StaticAuxCall(calleeLSym, params)
  5139  			call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5140  			if k == callTail {
  5141  				call.Op = ssa.OpTailLECall
  5142  				stksize = 0 // Tail call does not use stack. We reuse caller's frame.
  5143  			}
  5144  		default:
  5145  			s.Fatalf("bad call type %v %v", n.Op(), n)
  5146  		}
  5147  		call.AddArgs(callArgs...)
  5148  		call.AuxInt = stksize // Call operations carry the argsize of the callee along with them
  5149  	}
  5150  	s.prevCall = call
  5151  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(ACResults)), call)
  5152  	// Insert VarLive opcodes.
  5153  	for _, v := range n.KeepAlive {
  5154  		if !v.Addrtaken() {
  5155  			s.Fatalf("KeepAlive variable %v must have Addrtaken set", v)
  5156  		}
  5157  		switch v.Class {
  5158  		case ir.PAUTO, ir.PPARAM, ir.PPARAMOUT:
  5159  		default:
  5160  			s.Fatalf("KeepAlive variable %v must be Auto or Arg", v)
  5161  		}
  5162  		s.vars[memVar] = s.newValue1A(ssa.OpVarLive, types.TypeMem, v, s.mem())
  5163  	}
  5164  
  5165  	// Finish block for defers
  5166  	if k == callDefer || k == callDeferStack || isCallDeferRangeFunc {
  5167  		b := s.endBlock()
  5168  		b.Kind = ssa.BlockDefer
  5169  		b.SetControl(call)
  5170  		bNext := s.f.NewBlock(ssa.BlockPlain)
  5171  		b.AddEdgeTo(bNext)
  5172  		r := s.f.DeferReturn // Share a single deferreturn among all defers
  5173  		if r == nil {
  5174  			r = s.f.NewBlock(ssa.BlockPlain)
  5175  			s.startBlock(r)
  5176  			s.exit()
  5177  			s.f.DeferReturn = r
  5178  		}
  5179  		b.AddEdgeTo(r) // Add recover edge to exit code.  This is a fake edge to keep the block live.
  5180  		b.Likely = ssa.BranchLikely
  5181  		s.startBlock(bNext)
  5182  	}
  5183  
  5184  	if len(res) == 0 || k != callNormal {
  5185  		// call has no return value. Continue with the next statement.
  5186  		return nil
  5187  	}
  5188  	fp := res[0]
  5189  	if returnResultAddr {
  5190  		return s.resultAddrOfCall(call, 0, fp.Type)
  5191  	}
  5192  	return s.newValue1I(ssa.OpSelectN, fp.Type, 0, call)
  5193  }
  5194  
  5195  // maybeNilCheckClosure checks if a nil check of a closure is needed in some
  5196  // architecture-dependent situations and, if so, emits the nil check.
  5197  func (s *state) maybeNilCheckClosure(closure *ssa.Value, k callKind) {
  5198  	if Arch.LinkArch.Family == sys.Wasm || buildcfg.GOOS == "aix" && k != callGo {
  5199  		// On AIX, the closure needs to be verified as fn can be nil, except if it's a call go. This needs to be handled by the runtime to have the "go of nil func value" error.
  5200  		// TODO(neelance): On other architectures this should be eliminated by the optimization steps
  5201  		s.nilCheck(closure)
  5202  	}
  5203  }
  5204  
  5205  // getClosureAndRcvr returns values for the appropriate closure and receiver of an
  5206  // interface call
  5207  func (s *state) getClosureAndRcvr(fn *ir.SelectorExpr) (*ssa.Value, *ssa.Value) {
  5208  	i := s.expr(fn.X)
  5209  	itab := s.newValue1(ssa.OpITab, types.Types[types.TUINTPTR], i)
  5210  	s.nilCheck(itab)
  5211  	itabidx := fn.Offset() + rttype.ITab.OffsetOf("Fun")
  5212  	closure := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.UintptrPtr, itabidx, itab)
  5213  	rcvr := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, i)
  5214  	return closure, rcvr
  5215  }
  5216  
  5217  // etypesign returns the signed-ness of e, for integer/pointer etypes.
  5218  // -1 means signed, +1 means unsigned, 0 means non-integer/non-pointer.
  5219  func etypesign(e types.Kind) int8 {
  5220  	switch e {
  5221  	case types.TINT8, types.TINT16, types.TINT32, types.TINT64, types.TINT:
  5222  		return -1
  5223  	case types.TUINT8, types.TUINT16, types.TUINT32, types.TUINT64, types.TUINT, types.TUINTPTR, types.TUNSAFEPTR:
  5224  		return +1
  5225  	}
  5226  	return 0
  5227  }
  5228  
  5229  // addr converts the address of the expression n to SSA, adds it to s and returns the SSA result.
  5230  // The value that the returned Value represents is guaranteed to be non-nil.
  5231  func (s *state) addr(n ir.Node) *ssa.Value {
  5232  	if n.Op() != ir.ONAME {
  5233  		s.pushLine(n.Pos())
  5234  		defer s.popLine()
  5235  	}
  5236  
  5237  	if s.canSSA(n) {
  5238  		// This happens in weird, always-panics cases, like:
  5239  		//     var x [0][2]int
  5240  		//     x[i][j] = 5
  5241  		// The outer assignment, ...[j] = 5, is a fine
  5242  		// assignment to do, but requires computing the address
  5243  		// &x[i], which will always panic when evaluated.
  5244  		// We just return something reasonable in this case.
  5245  		// It will be dynamically unreachable. See issue 77635.
  5246  		return s.newValue1A(ssa.OpAddr, n.Type().PtrTo(), ir.Syms.Zerobase, s.sb)
  5247  	}
  5248  
  5249  	t := types.NewPtr(n.Type())
  5250  	linksymOffset := func(lsym *obj.LSym, offset int64) *ssa.Value {
  5251  		v := s.entryNewValue1A(ssa.OpAddr, t, lsym, s.sb)
  5252  		// TODO: Make OpAddr use AuxInt as well as Aux.
  5253  		if offset != 0 {
  5254  			v = s.entryNewValue1I(ssa.OpOffPtr, v.Type, offset, v)
  5255  		}
  5256  		return v
  5257  	}
  5258  	switch n.Op() {
  5259  	case ir.OLINKSYMOFFSET:
  5260  		no := n.(*ir.LinksymOffsetExpr)
  5261  		return linksymOffset(no.Linksym, no.Offset_)
  5262  	case ir.ONAME:
  5263  		n := n.(*ir.Name)
  5264  		if n.Heapaddr != nil {
  5265  			return s.expr(n.Heapaddr)
  5266  		}
  5267  		switch n.Class {
  5268  		case ir.PEXTERN:
  5269  			// global variable
  5270  			return linksymOffset(n.Linksym(), 0)
  5271  		case ir.PPARAM:
  5272  			// parameter slot
  5273  			v := s.decladdrs[n]
  5274  			if v != nil {
  5275  				return v
  5276  			}
  5277  			s.Fatalf("addr of undeclared ONAME %v. declared: %v", n, s.decladdrs)
  5278  			return nil
  5279  		case ir.PAUTO:
  5280  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), !ir.IsAutoTmp(n))
  5281  
  5282  		case ir.PPARAMOUT: // Same as PAUTO -- cannot generate LEA early.
  5283  			// ensure that we reuse symbols for out parameters so
  5284  			// that cse works on their addresses
  5285  			return s.newValue2Apos(ssa.OpLocalAddr, t, n, s.sp, s.mem(), true)
  5286  		default:
  5287  			s.Fatalf("variable address class %v not implemented", n.Class)
  5288  			return nil
  5289  		}
  5290  	case ir.ORESULT:
  5291  		// load return from callee
  5292  		n := n.(*ir.ResultExpr)
  5293  		return s.resultAddrOfCall(s.prevCall, n.Index, n.Type())
  5294  	case ir.OINDEX:
  5295  		n := n.(*ir.IndexExpr)
  5296  		if n.X.Type().IsSlice() {
  5297  			a := s.expr(n.X)
  5298  			i := s.expr(n.Index)
  5299  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], a)
  5300  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5301  			p := s.newValue1(ssa.OpSlicePtr, t, a)
  5302  			return s.newValue2(ssa.OpPtrIndex, t, p, i)
  5303  		} else { // array
  5304  			a := s.addr(n.X)
  5305  			i := s.expr(n.Index)
  5306  			len := s.constInt(types.Types[types.TINT], n.X.Type().NumElem())
  5307  			i = s.boundsCheck(i, len, ssa.BoundsIndex, n.Bounded())
  5308  			return s.newValue2(ssa.OpPtrIndex, types.NewPtr(n.X.Type().Elem()), a, i)
  5309  		}
  5310  	case ir.ODEREF:
  5311  		n := n.(*ir.StarExpr)
  5312  		return s.exprPtr(n.X, n.Bounded(), n.Pos())
  5313  	case ir.ODOT:
  5314  		n := n.(*ir.SelectorExpr)
  5315  		p := s.addr(n.X)
  5316  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5317  	case ir.ODOTPTR:
  5318  		n := n.(*ir.SelectorExpr)
  5319  		p := s.exprPtr(n.X, n.Bounded(), n.Pos())
  5320  		return s.newValue1I(ssa.OpOffPtr, t, n.Offset(), p)
  5321  	case ir.OCONVNOP:
  5322  		n := n.(*ir.ConvExpr)
  5323  		if n.Type() == n.X.Type() {
  5324  			return s.addr(n.X)
  5325  		}
  5326  		addr := s.addr(n.X)
  5327  		return s.newValue1(ssa.OpCopy, t, addr) // ensure that addr has the right type
  5328  	case ir.OCALLFUNC, ir.OCALLINTER:
  5329  		n := n.(*ir.CallExpr)
  5330  		return s.callAddr(n, callNormal)
  5331  	case ir.ODOTTYPE, ir.ODYNAMICDOTTYPE:
  5332  		var v *ssa.Value
  5333  		if n.Op() == ir.ODOTTYPE {
  5334  			v, _ = s.dottype(n.(*ir.TypeAssertExpr), false)
  5335  		} else {
  5336  			v, _ = s.dynamicDottype(n.(*ir.DynamicTypeAssertExpr), false)
  5337  		}
  5338  		if v.Op != ssa.OpLoad {
  5339  			s.Fatalf("dottype of non-load")
  5340  		}
  5341  		if v.Args[1] != s.mem() {
  5342  			s.Fatalf("memory no longer live from dottype load")
  5343  		}
  5344  		return v.Args[0]
  5345  	default:
  5346  		s.Fatalf("unhandled addr %v", n.Op())
  5347  		return nil
  5348  	}
  5349  }
  5350  
  5351  // canSSA reports whether n is SSA-able.
  5352  // n must be an ONAME (or an ODOT sequence with an ONAME base).
  5353  func (s *state) canSSA(n ir.Node) bool {
  5354  	if base.Flag.N != 0 {
  5355  		return false
  5356  	}
  5357  	for {
  5358  		nn := n
  5359  		if nn.Op() == ir.ODOT {
  5360  			nn := nn.(*ir.SelectorExpr)
  5361  			n = nn.X
  5362  			continue
  5363  		}
  5364  		if nn.Op() == ir.OINDEX {
  5365  			nn := nn.(*ir.IndexExpr)
  5366  			if nn.X.Type().IsArray() {
  5367  				n = nn.X
  5368  				continue
  5369  			}
  5370  		}
  5371  		break
  5372  	}
  5373  	if n.Op() != ir.ONAME {
  5374  		return false
  5375  	}
  5376  	return s.canSSAName(n.(*ir.Name)) && ssa.CanSSA(n.Type())
  5377  }
  5378  
  5379  func (s *state) canSSAName(name *ir.Name) bool {
  5380  	if name.Addrtaken() || !name.OnStack() {
  5381  		return false
  5382  	}
  5383  	switch name.Class {
  5384  	case ir.PPARAMOUT:
  5385  		if s.hasdefer {
  5386  			// TODO: handle this case? Named return values must be
  5387  			// in memory so that the deferred function can see them.
  5388  			// Maybe do: if !strings.HasPrefix(n.String(), "~") { return false }
  5389  			// Or maybe not, see issue 18860.  Even unnamed return values
  5390  			// must be written back so if a defer recovers, the caller can see them.
  5391  			return false
  5392  		}
  5393  		if s.cgoUnsafeArgs {
  5394  			// Cgo effectively takes the address of all result args,
  5395  			// but the compiler can't see that.
  5396  			return false
  5397  		}
  5398  	}
  5399  	return true
  5400  	// TODO: try to make more variables SSAable?
  5401  }
  5402  
  5403  // exprPtr evaluates n to a pointer and nil-checks it.
  5404  func (s *state) exprPtr(n ir.Node, bounded bool, lineno src.XPos) *ssa.Value {
  5405  	p := s.expr(n)
  5406  	if bounded || n.NonNil() {
  5407  		if s.f.Frontend().Debug_checknil() && lineno.Line() > 1 {
  5408  			s.f.Warnl(lineno, "removed nil check")
  5409  		}
  5410  		return p
  5411  	}
  5412  	p = s.nilCheck(p)
  5413  	return p
  5414  }
  5415  
  5416  // nilCheck generates nil pointer checking code.
  5417  // Used only for automatically inserted nil checks,
  5418  // not for user code like 'x != nil'.
  5419  // Returns a "definitely not nil" copy of x to ensure proper ordering
  5420  // of the uses of the post-nilcheck pointer.
  5421  func (s *state) nilCheck(ptr *ssa.Value) *ssa.Value {
  5422  	if base.Debug.DisableNil != 0 || s.curfn.NilCheckDisabled() {
  5423  		return ptr
  5424  	}
  5425  	return s.newValue2(ssa.OpNilCheck, ptr.Type, ptr, s.mem())
  5426  }
  5427  
  5428  // boundsCheck generates bounds checking code. Checks if 0 <= idx <[=] len, branches to exit if not.
  5429  // Starts a new block on return.
  5430  // On input, len must be converted to full int width and be nonnegative.
  5431  // Returns idx converted to full int width.
  5432  // If bounded is true then caller guarantees the index is not out of bounds
  5433  // (but boundsCheck will still extend the index to full int width).
  5434  func (s *state) boundsCheck(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  5435  	idx = s.extendIndex(idx, len, kind, bounded)
  5436  
  5437  	if bounded || base.Flag.B != 0 {
  5438  		// If bounded or bounds checking is flag-disabled, then no check necessary,
  5439  		// just return the extended index.
  5440  		//
  5441  		// Here, bounded == true if the compiler generated the index itself,
  5442  		// such as in the expansion of a slice initializer. These indexes are
  5443  		// compiler-generated, not Go program variables, so they cannot be
  5444  		// attacker-controlled, so we can omit Spectre masking as well.
  5445  		//
  5446  		// Note that we do not want to omit Spectre masking in code like:
  5447  		//
  5448  		//	if 0 <= i && i < len(x) {
  5449  		//		use(x[i])
  5450  		//	}
  5451  		//
  5452  		// Lucky for us, bounded==false for that code.
  5453  		// In that case (handled below), we emit a bound check (and Spectre mask)
  5454  		// and then the prove pass will remove the bounds check.
  5455  		// In theory the prove pass could potentially remove certain
  5456  		// Spectre masks, but it's very delicate and probably better
  5457  		// to be conservative and leave them all in.
  5458  		return idx
  5459  	}
  5460  
  5461  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5462  	bPanic := s.f.NewBlock(ssa.BlockExit)
  5463  
  5464  	if !idx.Type.IsSigned() {
  5465  		switch kind {
  5466  		case ssa.BoundsIndex:
  5467  			kind = ssa.BoundsIndexU
  5468  		case ssa.BoundsSliceAlen:
  5469  			kind = ssa.BoundsSliceAlenU
  5470  		case ssa.BoundsSliceAcap:
  5471  			kind = ssa.BoundsSliceAcapU
  5472  		case ssa.BoundsSliceB:
  5473  			kind = ssa.BoundsSliceBU
  5474  		case ssa.BoundsSlice3Alen:
  5475  			kind = ssa.BoundsSlice3AlenU
  5476  		case ssa.BoundsSlice3Acap:
  5477  			kind = ssa.BoundsSlice3AcapU
  5478  		case ssa.BoundsSlice3B:
  5479  			kind = ssa.BoundsSlice3BU
  5480  		case ssa.BoundsSlice3C:
  5481  			kind = ssa.BoundsSlice3CU
  5482  		}
  5483  	}
  5484  
  5485  	var cmp *ssa.Value
  5486  	if kind == ssa.BoundsIndex || kind == ssa.BoundsIndexU {
  5487  		cmp = s.newValue2(ssa.OpIsInBounds, types.Types[types.TBOOL], idx, len)
  5488  	} else {
  5489  		cmp = s.newValue2(ssa.OpIsSliceInBounds, types.Types[types.TBOOL], idx, len)
  5490  	}
  5491  	b := s.endBlock()
  5492  	b.Kind = ssa.BlockIf
  5493  	b.SetControl(cmp)
  5494  	b.Likely = ssa.BranchLikely
  5495  	b.AddEdgeTo(bNext)
  5496  	b.AddEdgeTo(bPanic)
  5497  
  5498  	s.startBlock(bPanic)
  5499  	if Arch.LinkArch.Family == sys.Wasm {
  5500  		// TODO(khr): figure out how to do "register" based calling convention for bounds checks.
  5501  		// Should be similar to gcWriteBarrier, but I can't make it work.
  5502  		s.rtcall(BoundsCheckFunc[kind], false, nil, idx, len)
  5503  	} else {
  5504  		mem := s.newValue3I(ssa.OpPanicBounds, types.TypeMem, int64(kind), idx, len, s.mem())
  5505  		s.endBlock().SetControl(mem)
  5506  	}
  5507  	s.startBlock(bNext)
  5508  
  5509  	// In Spectre index mode, apply an appropriate mask to avoid speculative out-of-bounds accesses.
  5510  	if base.Flag.Cfg.SpectreIndex {
  5511  		op := ssa.OpSpectreIndex
  5512  		if kind != ssa.BoundsIndex && kind != ssa.BoundsIndexU {
  5513  			op = ssa.OpSpectreSliceIndex
  5514  		}
  5515  		idx = s.newValue2(op, types.Types[types.TINT], idx, len)
  5516  	}
  5517  
  5518  	return idx
  5519  }
  5520  
  5521  // If cmp (a bool) is false, panic using the given function.
  5522  func (s *state) check(cmp *ssa.Value, fn *obj.LSym) {
  5523  	b := s.endBlock()
  5524  	b.Kind = ssa.BlockIf
  5525  	b.SetControl(cmp)
  5526  	b.Likely = ssa.BranchLikely
  5527  	bNext := s.f.NewBlock(ssa.BlockPlain)
  5528  	line := s.peekPos()
  5529  	pos := base.Ctxt.PosTable.Pos(line)
  5530  	fl := funcLine{f: fn, base: pos.Base(), line: pos.Line()}
  5531  	bPanic := s.panics[fl]
  5532  	if bPanic == nil {
  5533  		bPanic = s.f.NewBlock(ssa.BlockPlain)
  5534  		s.panics[fl] = bPanic
  5535  		s.startBlock(bPanic)
  5536  		// The panic call takes/returns memory to ensure that the right
  5537  		// memory state is observed if the panic happens.
  5538  		s.rtcall(fn, false, nil)
  5539  	}
  5540  	b.AddEdgeTo(bNext)
  5541  	b.AddEdgeTo(bPanic)
  5542  	s.startBlock(bNext)
  5543  }
  5544  
  5545  func (s *state) intDivide(n ir.Node, a, b *ssa.Value) *ssa.Value {
  5546  	needcheck := true
  5547  	switch b.Op {
  5548  	case ssa.OpConst8, ssa.OpConst16, ssa.OpConst32, ssa.OpConst64:
  5549  		if b.AuxInt != 0 {
  5550  			needcheck = false
  5551  		}
  5552  	}
  5553  	if needcheck {
  5554  		// do a size-appropriate check for zero
  5555  		cmp := s.newValue2(s.ssaOp(ir.ONE, n.Type()), types.Types[types.TBOOL], b, s.zeroVal(n.Type()))
  5556  		s.check(cmp, ir.Syms.Panicdivide)
  5557  	}
  5558  	return s.newValue2(s.ssaOp(n.Op(), n.Type()), a.Type, a, b)
  5559  }
  5560  
  5561  // rtcall issues a call to the given runtime function fn with the listed args.
  5562  // Returns a slice of results of the given result types.
  5563  // The call is added to the end of the current block.
  5564  // If returns is false, the block is marked as an exit block.
  5565  func (s *state) rtcall(fn *obj.LSym, returns bool, results []*types.Type, args ...*ssa.Value) []*ssa.Value {
  5566  	s.prevCall = nil
  5567  	// Write args to the stack
  5568  	off := base.Ctxt.Arch.FixedFrameSize
  5569  	var callArgs []*ssa.Value
  5570  	var callArgTypes []*types.Type
  5571  
  5572  	for _, arg := range args {
  5573  		t := arg.Type
  5574  		off = types.RoundUp(off, t.Alignment())
  5575  		size := t.Size()
  5576  		callArgs = append(callArgs, arg)
  5577  		callArgTypes = append(callArgTypes, t)
  5578  		off += size
  5579  	}
  5580  	off = types.RoundUp(off, int64(types.RegSize))
  5581  
  5582  	// Issue call
  5583  	var call *ssa.Value
  5584  	aux := ssa.StaticAuxCall(fn, s.f.ABIDefault.ABIAnalyzeTypes(callArgTypes, results))
  5585  	callArgs = append(callArgs, s.mem())
  5586  	call = s.newValue0A(ssa.OpStaticLECall, aux.LateExpansionResultType(), aux)
  5587  	call.AddArgs(callArgs...)
  5588  	s.vars[memVar] = s.newValue1I(ssa.OpSelectN, types.TypeMem, int64(len(results)), call)
  5589  
  5590  	if !returns {
  5591  		// Finish block
  5592  		b := s.endBlock()
  5593  		b.Kind = ssa.BlockExit
  5594  		b.SetControl(call)
  5595  		call.AuxInt = off - base.Ctxt.Arch.FixedFrameSize
  5596  		if len(results) > 0 {
  5597  			s.Fatalf("panic call can't have results")
  5598  		}
  5599  		return nil
  5600  	}
  5601  
  5602  	// Load results
  5603  	res := make([]*ssa.Value, len(results))
  5604  	for i, t := range results {
  5605  		off = types.RoundUp(off, t.Alignment())
  5606  		res[i] = s.resultOfCall(call, int64(i), t)
  5607  		off += t.Size()
  5608  	}
  5609  	off = types.RoundUp(off, int64(types.PtrSize))
  5610  
  5611  	// Remember how much callee stack space we needed.
  5612  	call.AuxInt = off
  5613  
  5614  	return res
  5615  }
  5616  
  5617  // do *left = right for type t.
  5618  func (s *state) storeType(t *types.Type, left, right *ssa.Value, skip skipMask, leftIsStmt bool) {
  5619  	s.instrument(t, left, instrumentWrite)
  5620  
  5621  	if skip == 0 && (!t.HasPointers() || ssa.IsStackAddr(left)) {
  5622  		// Known to not have write barrier. Store the whole type.
  5623  		s.vars[memVar] = s.newValue3Apos(ssa.OpStore, types.TypeMem, t, left, right, s.mem(), leftIsStmt)
  5624  		return
  5625  	}
  5626  
  5627  	// store scalar fields first, so write barrier stores for
  5628  	// pointer fields can be grouped together, and scalar values
  5629  	// don't need to be live across the write barrier call.
  5630  	// TODO: if the writebarrier pass knows how to reorder stores,
  5631  	// we can do a single store here as long as skip==0.
  5632  	s.storeTypeScalars(t, left, right, skip)
  5633  	if skip&skipPtr == 0 && t.HasPointers() {
  5634  		s.storeTypePtrs(t, left, right)
  5635  	}
  5636  }
  5637  
  5638  // do *left = right for all scalar (non-pointer) parts of t.
  5639  func (s *state) storeTypeScalars(t *types.Type, left, right *ssa.Value, skip skipMask) {
  5640  	switch {
  5641  	case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex() || t.IsSIMD():
  5642  		s.store(t, left, right)
  5643  	case t.IsPtrShaped():
  5644  		if t.IsPtr() && t.Elem().NotInHeap() {
  5645  			s.store(t, left, right) // see issue 42032
  5646  		}
  5647  		// otherwise, no scalar fields.
  5648  	case t.IsString():
  5649  		if skip&skipLen != 0 {
  5650  			return
  5651  		}
  5652  		len := s.newValue1(ssa.OpStringLen, types.Types[types.TINT], right)
  5653  		lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5654  		s.store(types.Types[types.TINT], lenAddr, len)
  5655  	case t.IsSlice():
  5656  		if skip&skipLen == 0 {
  5657  			len := s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], right)
  5658  			lenAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, s.config.PtrSize, left)
  5659  			s.store(types.Types[types.TINT], lenAddr, len)
  5660  		}
  5661  		if skip&skipCap == 0 {
  5662  			cap := s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], right)
  5663  			capAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.IntPtr, 2*s.config.PtrSize, left)
  5664  			s.store(types.Types[types.TINT], capAddr, cap)
  5665  		}
  5666  	case t.IsInterface():
  5667  		// itab field doesn't need a write barrier (even though it is a pointer).
  5668  		itab := s.newValue1(ssa.OpITab, s.f.Config.Types.BytePtr, right)
  5669  		s.store(types.Types[types.TUINTPTR], left, itab)
  5670  	case isStructNotSIMD(t):
  5671  		n := t.NumFields()
  5672  		for i := 0; i < n; i++ {
  5673  			ft := t.FieldType(i)
  5674  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5675  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5676  			s.storeTypeScalars(ft, addr, val, 0)
  5677  		}
  5678  	case t.IsArray() && t.Size() == 0:
  5679  		// nothing
  5680  	case t.IsArray() && t.NumElem() == 1:
  5681  		s.storeTypeScalars(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right), 0)
  5682  	default:
  5683  		s.Fatalf("bad write barrier type %v", t)
  5684  	}
  5685  }
  5686  
  5687  // do *left = right for all pointer parts of t.
  5688  func (s *state) storeTypePtrs(t *types.Type, left, right *ssa.Value) {
  5689  	switch {
  5690  	case t.IsPtrShaped():
  5691  		if t.IsPtr() && t.Elem().NotInHeap() {
  5692  			break // see issue 42032
  5693  		}
  5694  		s.store(t, left, right)
  5695  	case t.IsString():
  5696  		ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, right)
  5697  		s.store(s.f.Config.Types.BytePtr, left, ptr)
  5698  	case t.IsSlice():
  5699  		elType := types.NewPtr(t.Elem())
  5700  		ptr := s.newValue1(ssa.OpSlicePtr, elType, right)
  5701  		s.store(elType, left, ptr)
  5702  	case t.IsInterface():
  5703  		// itab field is treated as a scalar.
  5704  		idata := s.newValue1(ssa.OpIData, s.f.Config.Types.BytePtr, right)
  5705  		idataAddr := s.newValue1I(ssa.OpOffPtr, s.f.Config.Types.BytePtrPtr, s.config.PtrSize, left)
  5706  		s.store(s.f.Config.Types.BytePtr, idataAddr, idata)
  5707  	case isStructNotSIMD(t):
  5708  		n := t.NumFields()
  5709  		for i := 0; i < n; i++ {
  5710  			ft := t.FieldType(i)
  5711  			if !ft.HasPointers() {
  5712  				continue
  5713  			}
  5714  			addr := s.newValue1I(ssa.OpOffPtr, ft.PtrTo(), t.FieldOff(i), left)
  5715  			val := s.newValue1I(ssa.OpStructSelect, ft, int64(i), right)
  5716  			s.storeTypePtrs(ft, addr, val)
  5717  		}
  5718  	case t.IsArray() && t.Size() == 0:
  5719  		// nothing
  5720  	case t.IsArray() && t.NumElem() == 1:
  5721  		s.storeTypePtrs(t.Elem(), left, s.newValue1I(ssa.OpArraySelect, t.Elem(), 0, right))
  5722  	default:
  5723  		s.Fatalf("bad write barrier type %v", t)
  5724  	}
  5725  }
  5726  
  5727  // putArg evaluates n for the purpose of passing it as an argument to a function and returns the value for the call.
  5728  func (s *state) putArg(n ir.Node, t *types.Type) *ssa.Value {
  5729  	var a *ssa.Value
  5730  	if !ssa.CanSSA(t) {
  5731  		a = s.newValue2(ssa.OpDereference, t, s.addr(n), s.mem())
  5732  	} else {
  5733  		a = s.expr(n)
  5734  	}
  5735  	return a
  5736  }
  5737  
  5738  // slice computes the slice v[i:j:k] and returns ptr, len, and cap of result.
  5739  // i,j,k may be nil, in which case they are set to their default value.
  5740  // v may be a slice, string or pointer to an array.
  5741  func (s *state) slice(v, i, j, k *ssa.Value, bounded bool) (p, l, c *ssa.Value) {
  5742  	t := v.Type
  5743  	var ptr, len, cap *ssa.Value
  5744  	switch {
  5745  	case t.IsSlice():
  5746  		ptr = s.newValue1(ssa.OpSlicePtr, types.NewPtr(t.Elem()), v)
  5747  		len = s.newValue1(ssa.OpSliceLen, types.Types[types.TINT], v)
  5748  		cap = s.newValue1(ssa.OpSliceCap, types.Types[types.TINT], v)
  5749  	case t.IsString():
  5750  		ptr = s.newValue1(ssa.OpStringPtr, types.NewPtr(types.Types[types.TUINT8]), v)
  5751  		len = s.newValue1(ssa.OpStringLen, types.Types[types.TINT], v)
  5752  		cap = len
  5753  	case t.IsPtr():
  5754  		if !t.Elem().IsArray() {
  5755  			s.Fatalf("bad ptr to array in slice %v\n", t)
  5756  		}
  5757  		nv := s.nilCheck(v)
  5758  		ptr = s.newValue1(ssa.OpCopy, types.NewPtr(t.Elem().Elem()), nv)
  5759  		len = s.constInt(types.Types[types.TINT], t.Elem().NumElem())
  5760  		cap = len
  5761  	default:
  5762  		s.Fatalf("bad type in slice %v\n", t)
  5763  	}
  5764  
  5765  	// Set default values
  5766  	if i == nil {
  5767  		i = s.constInt(types.Types[types.TINT], 0)
  5768  	}
  5769  	if j == nil {
  5770  		j = len
  5771  	}
  5772  	three := true
  5773  	if k == nil {
  5774  		three = false
  5775  		k = cap
  5776  	}
  5777  
  5778  	// Panic if slice indices are not in bounds.
  5779  	// Make sure we check these in reverse order so that we're always
  5780  	// comparing against a value known to be nonnegative. See issue 28797.
  5781  	if three {
  5782  		if k != cap {
  5783  			kind := ssa.BoundsSlice3Alen
  5784  			if t.IsSlice() {
  5785  				kind = ssa.BoundsSlice3Acap
  5786  			}
  5787  			k = s.boundsCheck(k, cap, kind, bounded)
  5788  		}
  5789  		if j != k {
  5790  			j = s.boundsCheck(j, k, ssa.BoundsSlice3B, bounded)
  5791  		}
  5792  		i = s.boundsCheck(i, j, ssa.BoundsSlice3C, bounded)
  5793  	} else {
  5794  		if j != k {
  5795  			kind := ssa.BoundsSliceAlen
  5796  			if t.IsSlice() {
  5797  				kind = ssa.BoundsSliceAcap
  5798  			}
  5799  			j = s.boundsCheck(j, k, kind, bounded)
  5800  		}
  5801  		i = s.boundsCheck(i, j, ssa.BoundsSliceB, bounded)
  5802  	}
  5803  
  5804  	// Word-sized integer operations.
  5805  	subOp := s.ssaOp(ir.OSUB, types.Types[types.TINT])
  5806  	mulOp := s.ssaOp(ir.OMUL, types.Types[types.TINT])
  5807  	andOp := s.ssaOp(ir.OAND, types.Types[types.TINT])
  5808  
  5809  	// Calculate the length (rlen) and capacity (rcap) of the new slice.
  5810  	// For strings the capacity of the result is unimportant. However,
  5811  	// we use rcap to test if we've generated a zero-length slice.
  5812  	// Use length of strings for that.
  5813  	rlen := s.newValue2(subOp, types.Types[types.TINT], j, i)
  5814  	rcap := rlen
  5815  	if j != k && !t.IsString() {
  5816  		rcap = s.newValue2(subOp, types.Types[types.TINT], k, i)
  5817  	}
  5818  
  5819  	if (i.Op == ssa.OpConst64 || i.Op == ssa.OpConst32) && i.AuxInt == 0 {
  5820  		// No pointer arithmetic necessary.
  5821  		return ptr, rlen, rcap
  5822  	}
  5823  
  5824  	// Calculate the base pointer (rptr) for the new slice.
  5825  	//
  5826  	// Generate the following code assuming that indexes are in bounds.
  5827  	// The masking is to make sure that we don't generate a slice
  5828  	// that points to the next object in memory. We cannot just set
  5829  	// the pointer to nil because then we would create a nil slice or
  5830  	// string.
  5831  	//
  5832  	//     rcap = k - i
  5833  	//     rlen = j - i
  5834  	//     rptr = ptr + (mask(rcap) & (i * stride))
  5835  	//
  5836  	// Where mask(x) is 0 if x==0 and -1 if x>0 and stride is the width
  5837  	// of the element type.
  5838  	stride := s.constInt(types.Types[types.TINT], ptr.Type.Elem().Size())
  5839  
  5840  	// The delta is the number of bytes to offset ptr by.
  5841  	delta := s.newValue2(mulOp, types.Types[types.TINT], i, stride)
  5842  
  5843  	// If we're slicing to the point where the capacity is zero,
  5844  	// zero out the delta.
  5845  	mask := s.newValue1(ssa.OpSlicemask, types.Types[types.TINT], rcap)
  5846  	delta = s.newValue2(andOp, types.Types[types.TINT], delta, mask)
  5847  
  5848  	// Compute rptr = ptr + delta.
  5849  	rptr := s.newValue2(ssa.OpAddPtr, ptr.Type, ptr, delta)
  5850  
  5851  	return rptr, rlen, rcap
  5852  }
  5853  
  5854  type u642fcvtTab struct {
  5855  	leq, cvt2F, and, rsh, or, add ssa.Op
  5856  	one                           func(*state, *types.Type, int64) *ssa.Value
  5857  }
  5858  
  5859  var u64_f64 = u642fcvtTab{
  5860  	leq:   ssa.OpLeq64,
  5861  	cvt2F: ssa.OpCvt64to64F,
  5862  	and:   ssa.OpAnd64,
  5863  	rsh:   ssa.OpRsh64Ux64,
  5864  	or:    ssa.OpOr64,
  5865  	add:   ssa.OpAdd64F,
  5866  	one:   (*state).constInt64,
  5867  }
  5868  
  5869  var u64_f32 = u642fcvtTab{
  5870  	leq:   ssa.OpLeq64,
  5871  	cvt2F: ssa.OpCvt64to32F,
  5872  	and:   ssa.OpAnd64,
  5873  	rsh:   ssa.OpRsh64Ux64,
  5874  	or:    ssa.OpOr64,
  5875  	add:   ssa.OpAdd32F,
  5876  	one:   (*state).constInt64,
  5877  }
  5878  
  5879  func (s *state) uint64Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5880  	return s.uint64Tofloat(&u64_f64, n, x, ft, tt)
  5881  }
  5882  
  5883  func (s *state) uint64Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5884  	return s.uint64Tofloat(&u64_f32, n, x, ft, tt)
  5885  }
  5886  
  5887  func (s *state) uint64Tofloat(cvttab *u642fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5888  	// if x >= 0 {
  5889  	//    result = (floatY) x
  5890  	// } else {
  5891  	// 	  y = uintX(x) ; y = x & 1
  5892  	// 	  z = uintX(x) ; z = z >> 1
  5893  	// 	  z = z | y
  5894  	// 	  result = floatY(z)
  5895  	// 	  result = result + result
  5896  	// }
  5897  	//
  5898  	// Code borrowed from old code generator.
  5899  	// What's going on: large 64-bit "unsigned" looks like
  5900  	// negative number to hardware's integer-to-float
  5901  	// conversion. However, because the mantissa is only
  5902  	// 63 bits, we don't need the LSB, so instead we do an
  5903  	// unsigned right shift (divide by two), convert, and
  5904  	// double. However, before we do that, we need to be
  5905  	// sure that we do not lose a "1" if that made the
  5906  	// difference in the resulting rounding. Therefore, we
  5907  	// preserve it, and OR (not ADD) it back in. The case
  5908  	// that matters is when the eleven discarded bits are
  5909  	// equal to 10000000001; that rounds up, and the 1 cannot
  5910  	// be lost else it would round down if the LSB of the
  5911  	// candidate mantissa is 0.
  5912  
  5913  	cmp := s.newValue2(cvttab.leq, types.Types[types.TBOOL], s.zeroVal(ft), x)
  5914  
  5915  	b := s.endBlock()
  5916  	b.Kind = ssa.BlockIf
  5917  	b.SetControl(cmp)
  5918  	b.Likely = ssa.BranchLikely
  5919  
  5920  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5921  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5922  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5923  
  5924  	b.AddEdgeTo(bThen)
  5925  	s.startBlock(bThen)
  5926  	a0 := s.newValue1(cvttab.cvt2F, tt, x)
  5927  	s.vars[n] = a0
  5928  	s.endBlock()
  5929  	bThen.AddEdgeTo(bAfter)
  5930  
  5931  	b.AddEdgeTo(bElse)
  5932  	s.startBlock(bElse)
  5933  	one := cvttab.one(s, ft, 1)
  5934  	y := s.newValue2(cvttab.and, ft, x, one)
  5935  	z := s.newValue2(cvttab.rsh, ft, x, one)
  5936  	z = s.newValue2(cvttab.or, ft, z, y)
  5937  	a := s.newValue1(cvttab.cvt2F, tt, z)
  5938  	a1 := s.newValue2(cvttab.add, tt, a, a)
  5939  	s.vars[n] = a1
  5940  	s.endBlock()
  5941  	bElse.AddEdgeTo(bAfter)
  5942  
  5943  	s.startBlock(bAfter)
  5944  	return s.variable(n, n.Type())
  5945  }
  5946  
  5947  type u322fcvtTab struct {
  5948  	cvtI2F, cvtF2F ssa.Op
  5949  }
  5950  
  5951  var u32_f64 = u322fcvtTab{
  5952  	cvtI2F: ssa.OpCvt32to64F,
  5953  	cvtF2F: ssa.OpCopy,
  5954  }
  5955  
  5956  var u32_f32 = u322fcvtTab{
  5957  	cvtI2F: ssa.OpCvt32to32F,
  5958  	cvtF2F: ssa.OpCvt64Fto32F,
  5959  }
  5960  
  5961  func (s *state) uint32Tofloat64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5962  	return s.uint32Tofloat(&u32_f64, n, x, ft, tt)
  5963  }
  5964  
  5965  func (s *state) uint32Tofloat32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5966  	return s.uint32Tofloat(&u32_f32, n, x, ft, tt)
  5967  }
  5968  
  5969  func (s *state) uint32Tofloat(cvttab *u322fcvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  5970  	// if x >= 0 {
  5971  	// 	result = floatY(x)
  5972  	// } else {
  5973  	// 	result = floatY(float64(x) + (1<<32))
  5974  	// }
  5975  	cmp := s.newValue2(ssa.OpLeq32, types.Types[types.TBOOL], s.zeroVal(ft), x)
  5976  	b := s.endBlock()
  5977  	b.Kind = ssa.BlockIf
  5978  	b.SetControl(cmp)
  5979  	b.Likely = ssa.BranchLikely
  5980  
  5981  	bThen := s.f.NewBlock(ssa.BlockPlain)
  5982  	bElse := s.f.NewBlock(ssa.BlockPlain)
  5983  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  5984  
  5985  	b.AddEdgeTo(bThen)
  5986  	s.startBlock(bThen)
  5987  	a0 := s.newValue1(cvttab.cvtI2F, tt, x)
  5988  	s.vars[n] = a0
  5989  	s.endBlock()
  5990  	bThen.AddEdgeTo(bAfter)
  5991  
  5992  	b.AddEdgeTo(bElse)
  5993  	s.startBlock(bElse)
  5994  	a1 := s.newValue1(ssa.OpCvt32to64F, types.Types[types.TFLOAT64], x)
  5995  	twoToThe32 := s.constFloat64(types.Types[types.TFLOAT64], float64(1<<32))
  5996  	a2 := s.newValue2(ssa.OpAdd64F, types.Types[types.TFLOAT64], a1, twoToThe32)
  5997  	a3 := s.newValue1(cvttab.cvtF2F, tt, a2)
  5998  
  5999  	s.vars[n] = a3
  6000  	s.endBlock()
  6001  	bElse.AddEdgeTo(bAfter)
  6002  
  6003  	s.startBlock(bAfter)
  6004  	return s.variable(n, n.Type())
  6005  }
  6006  
  6007  // referenceTypeBuiltin generates code for the len/cap builtins for maps and channels.
  6008  func (s *state) referenceTypeBuiltin(n *ir.UnaryExpr, x *ssa.Value) *ssa.Value {
  6009  	if !n.X.Type().IsMap() && !n.X.Type().IsChan() {
  6010  		s.Fatalf("node must be a map or a channel")
  6011  	}
  6012  	if n.X.Type().IsChan() && n.Op() == ir.OLEN {
  6013  		s.Fatalf("cannot inline len(chan)") // must use runtime.chanlen now
  6014  	}
  6015  	if n.X.Type().IsChan() && n.Op() == ir.OCAP {
  6016  		s.Fatalf("cannot inline cap(chan)") // must use runtime.chancap now
  6017  	}
  6018  	if n.X.Type().IsMap() && n.Op() == ir.OCAP {
  6019  		s.Fatalf("cannot inline cap(map)") // cap(map) does not exist
  6020  	}
  6021  	// if n == nil {
  6022  	//   return 0
  6023  	// } else {
  6024  	//   // len, the actual loadType depends
  6025  	//   return int(*((*loadType)n))
  6026  	//   // cap (chan only, not used for now)
  6027  	//   return *(((*int)n)+1)
  6028  	// }
  6029  	lenType := n.Type()
  6030  	nilValue := s.constNil(types.Types[types.TUINTPTR])
  6031  	cmp := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], x, nilValue)
  6032  	b := s.endBlock()
  6033  	b.Kind = ssa.BlockIf
  6034  	b.SetControl(cmp)
  6035  	b.Likely = ssa.BranchUnlikely
  6036  
  6037  	bThen := s.f.NewBlock(ssa.BlockPlain)
  6038  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6039  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6040  
  6041  	// length/capacity of a nil map/chan is zero
  6042  	b.AddEdgeTo(bThen)
  6043  	s.startBlock(bThen)
  6044  	s.vars[n] = s.zeroVal(lenType)
  6045  	s.endBlock()
  6046  	bThen.AddEdgeTo(bAfter)
  6047  
  6048  	b.AddEdgeTo(bElse)
  6049  	s.startBlock(bElse)
  6050  	switch n.Op() {
  6051  	case ir.OLEN:
  6052  		if n.X.Type().IsMap() {
  6053  			// length is stored in the first word, but needs conversion to int.
  6054  			loadType := reflectdata.MapType().Field(0).Type // uint64
  6055  			load := s.load(loadType, x)
  6056  			s.vars[n] = s.conv(nil, load, loadType, lenType) // integer conversion doesn't need Node
  6057  		} else {
  6058  			// length is stored in the first word for chan, no conversion needed.
  6059  			s.vars[n] = s.load(lenType, x)
  6060  		}
  6061  	case ir.OCAP:
  6062  		// capacity is stored in the second word for chan
  6063  		sw := s.newValue1I(ssa.OpOffPtr, lenType.PtrTo(), lenType.Size(), x)
  6064  		s.vars[n] = s.load(lenType, sw)
  6065  	default:
  6066  		s.Fatalf("op must be OLEN or OCAP")
  6067  	}
  6068  	s.endBlock()
  6069  	bElse.AddEdgeTo(bAfter)
  6070  
  6071  	s.startBlock(bAfter)
  6072  	return s.variable(n, lenType)
  6073  }
  6074  
  6075  type f2uCvtTab struct {
  6076  	ltf, cvt2U, subf, or ssa.Op
  6077  	floatValue           func(*state, *types.Type, float64) *ssa.Value
  6078  	intValue             func(*state, *types.Type, int64) *ssa.Value
  6079  	cutoff               uint64
  6080  }
  6081  
  6082  var f32_u64 = f2uCvtTab{
  6083  	ltf:        ssa.OpLess32F,
  6084  	cvt2U:      ssa.OpCvt32Fto64,
  6085  	subf:       ssa.OpSub32F,
  6086  	or:         ssa.OpOr64,
  6087  	floatValue: (*state).constFloat32,
  6088  	intValue:   (*state).constInt64,
  6089  	cutoff:     1 << 63,
  6090  }
  6091  
  6092  var f64_u64 = f2uCvtTab{
  6093  	ltf:        ssa.OpLess64F,
  6094  	cvt2U:      ssa.OpCvt64Fto64,
  6095  	subf:       ssa.OpSub64F,
  6096  	or:         ssa.OpOr64,
  6097  	floatValue: (*state).constFloat64,
  6098  	intValue:   (*state).constInt64,
  6099  	cutoff:     1 << 63,
  6100  }
  6101  
  6102  var f32_u32 = f2uCvtTab{
  6103  	ltf:        ssa.OpLess32F,
  6104  	cvt2U:      ssa.OpCvt32Fto32,
  6105  	subf:       ssa.OpSub32F,
  6106  	or:         ssa.OpOr32,
  6107  	floatValue: (*state).constFloat32,
  6108  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6109  	cutoff:     1 << 31,
  6110  }
  6111  
  6112  var f64_u32 = f2uCvtTab{
  6113  	ltf:        ssa.OpLess64F,
  6114  	cvt2U:      ssa.OpCvt64Fto32,
  6115  	subf:       ssa.OpSub64F,
  6116  	or:         ssa.OpOr32,
  6117  	floatValue: (*state).constFloat64,
  6118  	intValue:   func(s *state, t *types.Type, v int64) *ssa.Value { return s.constInt32(t, int32(v)) },
  6119  	cutoff:     1 << 31,
  6120  }
  6121  
  6122  func (s *state) float32ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6123  	return s.floatToUint(&f32_u64, n, x, ft, tt)
  6124  }
  6125  func (s *state) float64ToUint64(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6126  	return s.floatToUint(&f64_u64, n, x, ft, tt)
  6127  }
  6128  
  6129  func (s *state) float32ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6130  	return s.floatToUint(&f32_u32, n, x, ft, tt)
  6131  }
  6132  
  6133  func (s *state) float64ToUint32(n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6134  	return s.floatToUint(&f64_u32, n, x, ft, tt)
  6135  }
  6136  
  6137  func (s *state) floatToUint(cvttab *f2uCvtTab, n ir.Node, x *ssa.Value, ft, tt *types.Type) *ssa.Value {
  6138  	// cutoff:=1<<(intY_Size-1)
  6139  	// if x < floatX(cutoff) {
  6140  	// 	result = uintY(x) // bThen
  6141  	//  // gated by ConvertHash, clamp negative inputs to zero
  6142  	// 	if x < 0 { // unlikely
  6143  	// 		result = 0 // bZero
  6144  	// 	}
  6145  	// } else {
  6146  	// 	y = x - floatX(cutoff) // bElse
  6147  	// 	z = uintY(y)
  6148  	// 	result = z | -(cutoff)
  6149  	// }
  6150  
  6151  	cutoff := cvttab.floatValue(s, ft, float64(cvttab.cutoff))
  6152  	cmp := s.newValueOrSfCall2(cvttab.ltf, types.Types[types.TBOOL], x, cutoff)
  6153  	b := s.endBlock()
  6154  	b.Kind = ssa.BlockIf
  6155  	b.SetControl(cmp)
  6156  	b.Likely = ssa.BranchLikely
  6157  
  6158  	var bThen, bZero *ssa.Block
  6159  	// use salted hash to distinguish unsigned convert at a Pos from signed convert at a Pos
  6160  	newConversion := base.ConvertHash.MatchPosWithInfo(n.Pos(), "U", nil)
  6161  	if newConversion {
  6162  		bZero = s.f.NewBlock(ssa.BlockPlain)
  6163  		bThen = s.f.NewBlock(ssa.BlockIf)
  6164  	} else {
  6165  		bThen = s.f.NewBlock(ssa.BlockPlain)
  6166  	}
  6167  
  6168  	bElse := s.f.NewBlock(ssa.BlockPlain)
  6169  	bAfter := s.f.NewBlock(ssa.BlockPlain)
  6170  
  6171  	b.AddEdgeTo(bThen)
  6172  	s.startBlock(bThen)
  6173  	a0 := s.newValueOrSfCall1(cvttab.cvt2U, tt, x)
  6174  	s.vars[n] = a0
  6175  
  6176  	if newConversion {
  6177  		cmpz := s.newValueOrSfCall2(cvttab.ltf, types.Types[types.TBOOL], x, cvttab.floatValue(s, ft, 0.0))
  6178  		s.endBlock()
  6179  		bThen.SetControl(cmpz)
  6180  		bThen.AddEdgeTo(bZero)
  6181  		bThen.Likely = ssa.BranchUnlikely
  6182  		bThen.AddEdgeTo(bAfter)
  6183  
  6184  		s.startBlock(bZero)
  6185  		s.vars[n] = cvttab.intValue(s, tt, 0)
  6186  		s.endBlock()
  6187  		bZero.AddEdgeTo(bAfter)
  6188  	} else {
  6189  		s.endBlock()
  6190  		bThen.AddEdgeTo(bAfter)
  6191  	}
  6192  
  6193  	b.AddEdgeTo(bElse)
  6194  	s.startBlock(bElse)
  6195  	y := s.newValueOrSfCall2(cvttab.subf, ft, x, cutoff)
  6196  	y = s.newValueOrSfCall1(cvttab.cvt2U, tt, y)
  6197  	z := cvttab.intValue(s, tt, int64(-cvttab.cutoff))
  6198  	a1 := s.newValue2(cvttab.or, tt, y, z)
  6199  	s.vars[n] = a1
  6200  	s.endBlock()
  6201  	bElse.AddEdgeTo(bAfter)
  6202  
  6203  	s.startBlock(bAfter)
  6204  	return s.variable(n, n.Type())
  6205  }
  6206  
  6207  // dottype generates SSA for a type assertion node.
  6208  // commaok indicates whether to panic or return a bool.
  6209  // If commaok is false, resok will be nil.
  6210  func (s *state) dottype(n *ir.TypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6211  	iface := s.expr(n.X)              // input interface
  6212  	target := s.reflectType(n.Type()) // target type
  6213  	var targetItab *ssa.Value
  6214  	if n.ITab != nil {
  6215  		targetItab = s.expr(n.ITab)
  6216  	}
  6217  
  6218  	if n.UseNilPanic {
  6219  		if commaok {
  6220  			base.Fatalf("unexpected *ir.TypeAssertExpr with UseNilPanic == true && commaok == true")
  6221  		}
  6222  		if n.Type().IsInterface() {
  6223  			// Currently we do not expect the compiler to emit type assertions with UseNilPanic, that asserts to an interface type.
  6224  			// If needed, this can be relaxed in the future, but for now we can't assert that.
  6225  			base.Fatalf("unexpected *ir.TypeAssertExpr with UseNilPanic == true && Type().IsInterface() == true")
  6226  		}
  6227  		typs := s.f.Config.Types
  6228  		iface = s.newValue2(
  6229  			ssa.OpIMake,
  6230  			iface.Type,
  6231  			s.nilCheck(s.newValue1(ssa.OpITab, typs.BytePtr, iface)),
  6232  			s.newValue1(ssa.OpIData, typs.BytePtr, iface),
  6233  		)
  6234  	}
  6235  
  6236  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, nil, target, targetItab, commaok, n.Descriptor)
  6237  }
  6238  
  6239  func (s *state) dynamicDottype(n *ir.DynamicTypeAssertExpr, commaok bool) (res, resok *ssa.Value) {
  6240  	iface := s.expr(n.X)
  6241  	var source, target, targetItab *ssa.Value
  6242  	if n.SrcRType != nil {
  6243  		source = s.expr(n.SrcRType)
  6244  	}
  6245  	if !n.X.Type().IsEmptyInterface() && !n.Type().IsInterface() {
  6246  		byteptr := s.f.Config.Types.BytePtr
  6247  		targetItab = s.expr(n.ITab)
  6248  		// TODO(mdempsky): Investigate whether compiling n.RType could be
  6249  		// better than loading itab.typ.
  6250  		target = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), targetItab))
  6251  	} else {
  6252  		target = s.expr(n.RType)
  6253  	}
  6254  	return s.dottype1(n.Pos(), n.X.Type(), n.Type(), iface, source, target, targetItab, commaok, nil)
  6255  }
  6256  
  6257  // dottype1 implements a x.(T) operation. iface is the argument (x), dst is the type we're asserting to (T)
  6258  // and src is the type we're asserting from.
  6259  // source is the *runtime._type of src
  6260  // target is the *runtime._type of dst.
  6261  // If src is a nonempty interface and dst is not an interface, targetItab is an itab representing (dst, src). Otherwise it is nil.
  6262  // commaok is true if the caller wants a boolean success value. Otherwise, the generated code panics if the conversion fails.
  6263  // descriptor is a compiler-allocated internal/abi.TypeAssert whose address is passed to runtime.typeAssert when
  6264  // the target type is a compile-time-known non-empty interface. It may be nil.
  6265  func (s *state) dottype1(pos src.XPos, src, dst *types.Type, iface, source, target, targetItab *ssa.Value, commaok bool, descriptor *obj.LSym) (res, resok *ssa.Value) {
  6266  	typs := s.f.Config.Types
  6267  	byteptr := typs.BytePtr
  6268  	if dst.IsInterface() {
  6269  		if dst.IsEmptyInterface() {
  6270  			// Converting to an empty interface.
  6271  			// Input could be an empty or nonempty interface.
  6272  			if base.Debug.TypeAssert > 0 {
  6273  				base.WarnfAt(pos, "type assertion inlined")
  6274  			}
  6275  
  6276  			// Get itab/type field from input.
  6277  			itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6278  			// Conversion succeeds iff that field is not nil.
  6279  			cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6280  
  6281  			if src.IsEmptyInterface() && commaok {
  6282  				// Converting empty interface to empty interface with ,ok is just a nil check.
  6283  				return iface, cond
  6284  			}
  6285  
  6286  			// Branch on nilness.
  6287  			b := s.endBlock()
  6288  			b.Kind = ssa.BlockIf
  6289  			b.SetControl(cond)
  6290  			b.Likely = ssa.BranchLikely
  6291  			bOk := s.f.NewBlock(ssa.BlockPlain)
  6292  			bFail := s.f.NewBlock(ssa.BlockPlain)
  6293  			b.AddEdgeTo(bOk)
  6294  			b.AddEdgeTo(bFail)
  6295  
  6296  			if !commaok {
  6297  				// On failure, panic by calling panicnildottype.
  6298  				s.startBlock(bFail)
  6299  				s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6300  
  6301  				// On success, return (perhaps modified) input interface.
  6302  				s.startBlock(bOk)
  6303  				if src.IsEmptyInterface() {
  6304  					res = iface // Use input interface unchanged.
  6305  					return
  6306  				}
  6307  				// Load type out of itab, build interface with existing idata.
  6308  				off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
  6309  				typ := s.load(byteptr, off)
  6310  				idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6311  				res = s.newValue2(ssa.OpIMake, dst, typ, idata)
  6312  				return
  6313  			}
  6314  
  6315  			s.startBlock(bOk)
  6316  			// nonempty -> empty
  6317  			// Need to load type from itab
  6318  			off := s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab)
  6319  			s.vars[typVar] = s.load(byteptr, off)
  6320  			s.endBlock()
  6321  
  6322  			// itab is nil, might as well use that as the nil result.
  6323  			s.startBlock(bFail)
  6324  			s.vars[typVar] = itab
  6325  			s.endBlock()
  6326  
  6327  			// Merge point.
  6328  			bEnd := s.f.NewBlock(ssa.BlockPlain)
  6329  			bOk.AddEdgeTo(bEnd)
  6330  			bFail.AddEdgeTo(bEnd)
  6331  			s.startBlock(bEnd)
  6332  			idata := s.newValue1(ssa.OpIData, byteptr, iface)
  6333  			res = s.newValue2(ssa.OpIMake, dst, s.variable(typVar, byteptr), idata)
  6334  			resok = cond
  6335  			delete(s.vars, typVar) // no practical effect, just to indicate typVar is no longer live.
  6336  			return
  6337  		}
  6338  		// converting to a nonempty interface needs a runtime call.
  6339  		if base.Debug.TypeAssert > 0 {
  6340  			base.WarnfAt(pos, "type assertion not inlined")
  6341  		}
  6342  
  6343  		itab := s.newValue1(ssa.OpITab, byteptr, iface)
  6344  		data := s.newValue1(ssa.OpIData, types.Types[types.TUNSAFEPTR], iface)
  6345  
  6346  		// First, check for nil.
  6347  		bNil := s.f.NewBlock(ssa.BlockPlain)
  6348  		bNonNil := s.f.NewBlock(ssa.BlockPlain)
  6349  		bMerge := s.f.NewBlock(ssa.BlockPlain)
  6350  		cond := s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6351  		b := s.endBlock()
  6352  		b.Kind = ssa.BlockIf
  6353  		b.SetControl(cond)
  6354  		b.Likely = ssa.BranchLikely
  6355  		b.AddEdgeTo(bNonNil)
  6356  		b.AddEdgeTo(bNil)
  6357  
  6358  		s.startBlock(bNil)
  6359  		if commaok {
  6360  			s.vars[typVar] = itab // which will be nil
  6361  			b := s.endBlock()
  6362  			b.AddEdgeTo(bMerge)
  6363  		} else {
  6364  			// Panic if input is nil.
  6365  			s.rtcall(ir.Syms.Panicnildottype, false, nil, target)
  6366  		}
  6367  
  6368  		// Get typ, possibly by loading out of itab.
  6369  		s.startBlock(bNonNil)
  6370  		typ := itab
  6371  		if !src.IsEmptyInterface() {
  6372  			typ = s.load(byteptr, s.newValue1I(ssa.OpOffPtr, byteptr, rttype.ITab.OffsetOf("Type"), itab))
  6373  		}
  6374  
  6375  		// Check the cache first.
  6376  		var d *ssa.Value
  6377  		if descriptor != nil {
  6378  			d = s.newValue1A(ssa.OpAddr, byteptr, descriptor, s.sb)
  6379  			if base.Flag.N == 0 && rtabi.UseInterfaceSwitchCache(Arch.LinkArch.Family) {
  6380  				// Note: we can only use the cache if we have the right atomic load instruction.
  6381  				// Double-check that here.
  6382  				if intrinsics.lookup(Arch.LinkArch.Arch, "internal/runtime/atomic", "Loadp") == nil {
  6383  					s.Fatalf("atomic load not available")
  6384  				}
  6385  				// Pick right size ops.
  6386  				var mul, and, add, zext ssa.Op
  6387  				if s.config.PtrSize == 4 {
  6388  					mul = ssa.OpMul32
  6389  					and = ssa.OpAnd32
  6390  					add = ssa.OpAdd32
  6391  					zext = ssa.OpCopy
  6392  				} else {
  6393  					mul = ssa.OpMul64
  6394  					and = ssa.OpAnd64
  6395  					add = ssa.OpAdd64
  6396  					zext = ssa.OpZeroExt32to64
  6397  				}
  6398  
  6399  				loopHead := s.f.NewBlock(ssa.BlockPlain)
  6400  				loopBody := s.f.NewBlock(ssa.BlockPlain)
  6401  				cacheHit := s.f.NewBlock(ssa.BlockPlain)
  6402  				cacheMiss := s.f.NewBlock(ssa.BlockPlain)
  6403  
  6404  				// Load cache pointer out of descriptor, with an atomic load so
  6405  				// we ensure that we see a fully written cache.
  6406  				atomicLoad := s.newValue2(ssa.OpAtomicLoadPtr, types.NewTuple(typs.BytePtr, types.TypeMem), d, s.mem())
  6407  				cache := s.newValue1(ssa.OpSelect0, typs.BytePtr, atomicLoad)
  6408  				s.vars[memVar] = s.newValue1(ssa.OpSelect1, types.TypeMem, atomicLoad)
  6409  
  6410  				// Load hash from type or itab.
  6411  				var hash *ssa.Value
  6412  				if src.IsEmptyInterface() {
  6413  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, rttype.Type.OffsetOf("Hash"), typ), s.mem())
  6414  				} else {
  6415  					hash = s.newValue2(ssa.OpLoad, typs.UInt32, s.newValue1I(ssa.OpOffPtr, typs.UInt32Ptr, rttype.ITab.OffsetOf("Hash"), itab), s.mem())
  6416  				}
  6417  				hash = s.newValue1(zext, typs.Uintptr, hash)
  6418  				s.vars[hashVar] = hash
  6419  				// Load mask from cache.
  6420  				mask := s.newValue2(ssa.OpLoad, typs.Uintptr, cache, s.mem())
  6421  				// Jump to loop head.
  6422  				b := s.endBlock()
  6423  				b.AddEdgeTo(loopHead)
  6424  
  6425  				// At loop head, get pointer to the cache entry.
  6426  				//   e := &cache.Entries[hash&mask]
  6427  				s.startBlock(loopHead)
  6428  				idx := s.newValue2(and, typs.Uintptr, s.variable(hashVar, typs.Uintptr), mask)
  6429  				idx = s.newValue2(mul, typs.Uintptr, idx, s.uintptrConstant(uint64(2*s.config.PtrSize)))
  6430  				idx = s.newValue2(add, typs.Uintptr, idx, s.uintptrConstant(uint64(s.config.PtrSize)))
  6431  				e := s.newValue2(ssa.OpAddPtr, typs.UintptrPtr, cache, idx)
  6432  				//   hash++
  6433  				s.vars[hashVar] = s.newValue2(add, typs.Uintptr, s.variable(hashVar, typs.Uintptr), s.uintptrConstant(1))
  6434  
  6435  				// Look for a cache hit.
  6436  				//   if e.Typ == typ { goto hit }
  6437  				eTyp := s.newValue2(ssa.OpLoad, typs.Uintptr, e, s.mem())
  6438  				cmp1 := s.newValue2(ssa.OpEqPtr, typs.Bool, typ, eTyp)
  6439  				b = s.endBlock()
  6440  				b.Kind = ssa.BlockIf
  6441  				b.SetControl(cmp1)
  6442  				b.AddEdgeTo(cacheHit)
  6443  				b.AddEdgeTo(loopBody)
  6444  
  6445  				// Look for an empty entry, the tombstone for this hash table.
  6446  				//   if e.Typ == nil { goto miss }
  6447  				s.startBlock(loopBody)
  6448  				cmp2 := s.newValue2(ssa.OpEqPtr, typs.Bool, eTyp, s.constNil(typs.BytePtr))
  6449  				b = s.endBlock()
  6450  				b.Kind = ssa.BlockIf
  6451  				b.SetControl(cmp2)
  6452  				b.AddEdgeTo(cacheMiss)
  6453  				b.AddEdgeTo(loopHead)
  6454  
  6455  				// On a hit, load the data fields of the cache entry.
  6456  				//   Itab = e.Itab
  6457  				s.startBlock(cacheHit)
  6458  				eItab := s.newValue2(ssa.OpLoad, typs.BytePtr, s.newValue1I(ssa.OpOffPtr, typs.BytePtrPtr, s.config.PtrSize, e), s.mem())
  6459  				s.vars[typVar] = eItab
  6460  				b = s.endBlock()
  6461  				b.AddEdgeTo(bMerge)
  6462  
  6463  				// On a miss, call into the runtime to get the answer.
  6464  				s.startBlock(cacheMiss)
  6465  			}
  6466  		}
  6467  
  6468  		// Call into runtime to get itab for result.
  6469  		if descriptor != nil {
  6470  			itab = s.rtcall(ir.Syms.TypeAssert, true, []*types.Type{byteptr}, d, typ)[0]
  6471  		} else {
  6472  			var fn *obj.LSym
  6473  			if commaok {
  6474  				fn = ir.Syms.AssertE2I2
  6475  			} else {
  6476  				fn = ir.Syms.AssertE2I
  6477  			}
  6478  			itab = s.rtcall(fn, true, []*types.Type{byteptr}, target, typ)[0]
  6479  		}
  6480  		s.vars[typVar] = itab
  6481  		b = s.endBlock()
  6482  		b.AddEdgeTo(bMerge)
  6483  
  6484  		// Build resulting interface.
  6485  		s.startBlock(bMerge)
  6486  		itab = s.variable(typVar, byteptr)
  6487  		var ok *ssa.Value
  6488  		if commaok {
  6489  			ok = s.newValue2(ssa.OpNeqPtr, types.Types[types.TBOOL], itab, s.constNil(byteptr))
  6490  		}
  6491  		return s.newValue2(ssa.OpIMake, dst, itab, data), ok
  6492  	}
  6493  
  6494  	if base.Debug.TypeAssert > 0 {
  6495  		base.WarnfAt(pos, "type assertion inlined")
  6496  	}
  6497  
  6498  	// Converting to a concrete type.
  6499  	direct := types.IsDirectIface(dst)
  6500  	itab := s.newValue1(ssa.OpITab, byteptr, iface) // type word of interface
  6501  	if base.Debug.TypeAssert > 0 {
  6502  		base.WarnfAt(pos, "type assertion inlined")
  6503  	}
  6504  	var wantedFirstWord *ssa.Value
  6505  	if src.IsEmptyInterface() {
  6506  		// Looking for pointer to target type.
  6507  		wantedFirstWord = target
  6508  	} else {
  6509  		// Looking for pointer to itab for target type and source interface.
  6510  		wantedFirstWord = targetItab
  6511  	}
  6512  
  6513  	var tmp ir.Node     // temporary for use with large types
  6514  	var addr *ssa.Value // address of tmp
  6515  	if commaok && !ssa.CanSSA(dst) {
  6516  		// unSSAable type, use temporary.
  6517  		// TODO: get rid of some of these temporaries.
  6518  		tmp, addr = s.temp(pos, dst)
  6519  	}
  6520  
  6521  	cond := s.newValue2(ssa.OpEqPtr, types.Types[types.TBOOL], itab, wantedFirstWord)
  6522  	b := s.endBlock()
  6523  	b.Kind = ssa.BlockIf
  6524  	b.SetControl(cond)
  6525  	b.Likely = ssa.BranchLikely
  6526  
  6527  	bOk := s.f.NewBlock(ssa.BlockPlain)
  6528  	bFail := s.f.NewBlock(ssa.BlockPlain)
  6529  	b.AddEdgeTo(bOk)
  6530  	b.AddEdgeTo(bFail)
  6531  
  6532  	if !commaok {
  6533  		// on failure, panic by calling panicdottype
  6534  		s.startBlock(bFail)
  6535  		taddr := source
  6536  		if taddr == nil {
  6537  			taddr = s.reflectType(src)
  6538  		}
  6539  		if src.IsEmptyInterface() {
  6540  			s.rtcall(ir.Syms.PanicdottypeE, false, nil, itab, target, taddr)
  6541  		} else {
  6542  			s.rtcall(ir.Syms.PanicdottypeI, false, nil, itab, target, taddr)
  6543  		}
  6544  
  6545  		// on success, return data from interface
  6546  		s.startBlock(bOk)
  6547  		if direct {
  6548  			return s.newValue1(ssa.OpIData, dst, iface), nil
  6549  		}
  6550  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6551  		return s.load(dst, p), nil
  6552  	}
  6553  
  6554  	// commaok is the more complicated case because we have
  6555  	// a control flow merge point.
  6556  	bEnd := s.f.NewBlock(ssa.BlockPlain)
  6557  	// Note that we need a new valVar each time (unlike okVar where we can
  6558  	// reuse the variable) because it might have a different type every time.
  6559  	valVar := ssaMarker("val")
  6560  
  6561  	// type assertion succeeded
  6562  	s.startBlock(bOk)
  6563  	if tmp == nil {
  6564  		if direct {
  6565  			s.vars[valVar] = s.newValue1(ssa.OpIData, dst, iface)
  6566  		} else {
  6567  			p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6568  			s.vars[valVar] = s.load(dst, p)
  6569  		}
  6570  	} else {
  6571  		p := s.newValue1(ssa.OpIData, types.NewPtr(dst), iface)
  6572  		s.move(dst, addr, p)
  6573  	}
  6574  	s.vars[okVar] = s.constBool(true)
  6575  	s.endBlock()
  6576  	bOk.AddEdgeTo(bEnd)
  6577  
  6578  	// type assertion failed
  6579  	s.startBlock(bFail)
  6580  	if tmp == nil {
  6581  		s.vars[valVar] = s.zeroVal(dst)
  6582  	} else {
  6583  		s.zero(dst, addr)
  6584  	}
  6585  	s.vars[okVar] = s.constBool(false)
  6586  	s.endBlock()
  6587  	bFail.AddEdgeTo(bEnd)
  6588  
  6589  	// merge point
  6590  	s.startBlock(bEnd)
  6591  	if tmp == nil {
  6592  		res = s.variable(valVar, dst)
  6593  		delete(s.vars, valVar) // no practical effect, just to indicate typVar is no longer live.
  6594  	} else {
  6595  		res = s.load(dst, addr)
  6596  	}
  6597  	resok = s.variable(okVar, types.Types[types.TBOOL])
  6598  	delete(s.vars, okVar) // ditto
  6599  	return res, resok
  6600  }
  6601  
  6602  // temp allocates a temp of type t at position pos
  6603  func (s *state) temp(pos src.XPos, t *types.Type) (*ir.Name, *ssa.Value) {
  6604  	tmp := typecheck.TempAt(pos, s.curfn, t)
  6605  	if t.HasPointers() || (ssa.IsMergeCandidate(tmp) && t != deferstruct()) {
  6606  		s.vars[memVar] = s.newValue1A(ssa.OpVarDef, types.TypeMem, tmp, s.mem())
  6607  	}
  6608  	addr := s.addr(tmp)
  6609  	return tmp, addr
  6610  }
  6611  
  6612  // variable returns the value of a variable at the current location.
  6613  func (s *state) variable(n ir.Node, t *types.Type) *ssa.Value {
  6614  	v := s.vars[n]
  6615  	if v != nil {
  6616  		return v
  6617  	}
  6618  	v = s.fwdVars[n]
  6619  	if v != nil {
  6620  		return v
  6621  	}
  6622  
  6623  	if s.curBlock == s.f.Entry {
  6624  		// No variable should be live at entry.
  6625  		s.f.Fatalf("value %v (%v) incorrectly live at entry", n, v)
  6626  	}
  6627  	// Make a FwdRef, which records a value that's live on block input.
  6628  	// We'll find the matching definition as part of insertPhis.
  6629  	v = s.newValue0A(ssa.OpFwdRef, t, fwdRefAux{N: n})
  6630  	s.fwdVars[n] = v
  6631  	if n.Op() == ir.ONAME {
  6632  		s.addNamedValue(n.(*ir.Name), v)
  6633  	}
  6634  	return v
  6635  }
  6636  
  6637  func (s *state) mem() *ssa.Value {
  6638  	return s.variable(memVar, types.TypeMem)
  6639  }
  6640  
  6641  func (s *state) addNamedValue(n *ir.Name, v *ssa.Value) {
  6642  	if n.Class == ir.Pxxx {
  6643  		// Don't track our marker nodes (memVar etc.).
  6644  		return
  6645  	}
  6646  	if ir.IsAutoTmp(n) {
  6647  		// Don't track temporary variables.
  6648  		return
  6649  	}
  6650  	if n.Class == ir.PPARAMOUT {
  6651  		// Don't track named output values.  This prevents return values
  6652  		// from being assigned too early. See #14591 and #14762. TODO: allow this.
  6653  		return
  6654  	}
  6655  	loc := ssa.LocalSlot{N: n, Type: n.Type(), Off: 0}
  6656  	values, ok := s.f.NamedValues[loc]
  6657  	if !ok {
  6658  		s.f.Names = append(s.f.Names, &loc)
  6659  		s.f.CanonicalLocalSlots[loc] = &loc
  6660  	}
  6661  	s.f.NamedValues[loc] = append(values, v)
  6662  }
  6663  
  6664  // Branch is an unresolved branch.
  6665  type Branch struct {
  6666  	P *obj.Prog  // branch instruction
  6667  	B *ssa.Block // target
  6668  }
  6669  
  6670  // State contains state needed during Prog generation.
  6671  type State struct {
  6672  	ABI obj.ABI
  6673  
  6674  	pp *objw.Progs
  6675  
  6676  	// Branches remembers all the branch instructions we've seen
  6677  	// and where they would like to go.
  6678  	Branches []Branch
  6679  
  6680  	// JumpTables remembers all the jump tables we've seen.
  6681  	JumpTables []*ssa.Block
  6682  
  6683  	// bstart remembers where each block starts (indexed by block ID)
  6684  	bstart []*obj.Prog
  6685  
  6686  	maxarg int64 // largest frame size for arguments to calls made by the function
  6687  
  6688  	// Map from GC safe points to liveness index, generated by
  6689  	// liveness analysis.
  6690  	livenessMap liveness.Map
  6691  
  6692  	// partLiveArgs includes arguments that may be partially live, for which we
  6693  	// need to generate instructions that spill the argument registers.
  6694  	partLiveArgs map[*ir.Name]bool
  6695  
  6696  	// lineRunStart records the beginning of the current run of instructions
  6697  	// within a single block sharing the same line number
  6698  	// Used to move statement marks to the beginning of such runs.
  6699  	lineRunStart *obj.Prog
  6700  
  6701  	// wasm: The number of values on the WebAssembly stack. This is only used as a safeguard.
  6702  	OnWasmStackSkipped int
  6703  }
  6704  
  6705  func (s *State) FuncInfo() *obj.FuncInfo {
  6706  	return s.pp.CurFunc.LSym.Func()
  6707  }
  6708  
  6709  // Prog appends a new Prog.
  6710  func (s *State) Prog(as obj.As) *obj.Prog {
  6711  	p := s.pp.Prog(as)
  6712  	if objw.LosesStmtMark(as) {
  6713  		return p
  6714  	}
  6715  	// Float a statement start to the beginning of any same-line run.
  6716  	// lineRunStart is reset at block boundaries, which appears to work well.
  6717  	if s.lineRunStart == nil || s.lineRunStart.Pos.Line() != p.Pos.Line() {
  6718  		s.lineRunStart = p
  6719  	} else if p.Pos.IsStmt() == src.PosIsStmt {
  6720  		s.lineRunStart.Pos = s.lineRunStart.Pos.WithIsStmt()
  6721  		p.Pos = p.Pos.WithNotStmt()
  6722  	}
  6723  	return p
  6724  }
  6725  
  6726  // Pc returns the current Prog.
  6727  func (s *State) Pc() *obj.Prog {
  6728  	return s.pp.Next
  6729  }
  6730  
  6731  // SetPos sets the current source position.
  6732  func (s *State) SetPos(pos src.XPos) {
  6733  	s.pp.Pos = pos
  6734  }
  6735  
  6736  // Br emits a single branch instruction and returns the instruction.
  6737  // Not all architectures need the returned instruction, but otherwise
  6738  // the boilerplate is common to all.
  6739  func (s *State) Br(op obj.As, target *ssa.Block) *obj.Prog {
  6740  	p := s.Prog(op)
  6741  	p.To.Type = obj.TYPE_BRANCH
  6742  	s.Branches = append(s.Branches, Branch{P: p, B: target})
  6743  	return p
  6744  }
  6745  
  6746  // DebugFriendlySetPosFrom adjusts Pos.IsStmt subject to heuristics
  6747  // that reduce "jumpy" line number churn when debugging.
  6748  // Spill/fill/copy instructions from the register allocator,
  6749  // phi functions, and instructions with a no-pos position
  6750  // are examples of instructions that can cause churn.
  6751  func (s *State) DebugFriendlySetPosFrom(v *ssa.Value) {
  6752  	switch v.Op {
  6753  	case ssa.OpPhi, ssa.OpCopy, ssa.OpLoadReg, ssa.OpStoreReg:
  6754  		// These are not statements
  6755  		s.SetPos(v.Pos.WithNotStmt())
  6756  	default:
  6757  		p := v.Pos
  6758  		if p != src.NoXPos {
  6759  			// If the position is defined, update the position.
  6760  			// Also convert default IsStmt to NotStmt; only
  6761  			// explicit statement boundaries should appear
  6762  			// in the generated code.
  6763  			if p.IsStmt() != src.PosIsStmt {
  6764  				if s.pp.Pos.IsStmt() == src.PosIsStmt && s.pp.Pos.SameFileAndLine(p) {
  6765  					// If s.pp.Pos already has a statement mark, then it was set here (below) for
  6766  					// the previous value.  If an actual instruction had been emitted for that
  6767  					// value, then the statement mark would have been reset.  Since the statement
  6768  					// mark of s.pp.Pos was not reset, this position (file/line) still needs a
  6769  					// statement mark on an instruction.  If file and line for this value are
  6770  					// the same as the previous value, then the first instruction for this
  6771  					// value will work to take the statement mark.  Return early to avoid
  6772  					// resetting the statement mark.
  6773  					//
  6774  					// The reset of s.pp.Pos occurs in (*Progs).Prog() -- if it emits
  6775  					// an instruction, and the instruction's statement mark was set,
  6776  					// and it is not one of the LosesStmtMark instructions,
  6777  					// then Prog() resets the statement mark on the (*Progs).Pos.
  6778  					return
  6779  				}
  6780  				p = p.WithNotStmt()
  6781  				// Calls use the pos attached to v, but copy the statement mark from State
  6782  			}
  6783  			s.SetPos(p)
  6784  		} else {
  6785  			s.SetPos(s.pp.Pos.WithNotStmt())
  6786  		}
  6787  	}
  6788  }
  6789  
  6790  // emit argument info (locations on stack) for traceback.
  6791  func emitArgInfo(e *ssafn, f *ssa.Func, pp *objw.Progs) {
  6792  	ft := e.curfn.Type()
  6793  	if ft.NumRecvs() == 0 && ft.NumParams() == 0 {
  6794  		return
  6795  	}
  6796  
  6797  	x := EmitArgInfo(e.curfn, f.OwnAux.ABIInfo())
  6798  	x.Set(obj.AttrContentAddressable, true)
  6799  	e.curfn.LSym.Func().ArgInfo = x
  6800  
  6801  	// Emit a funcdata pointing at the arg info data.
  6802  	p := pp.Prog(obj.AFUNCDATA)
  6803  	p.From.SetConst(rtabi.FUNCDATA_ArgInfo)
  6804  	p.To.Type = obj.TYPE_MEM
  6805  	p.To.Name = obj.NAME_EXTERN
  6806  	p.To.Sym = x
  6807  }
  6808  
  6809  // emit argument info (locations on stack) of f for traceback.
  6810  func EmitArgInfo(f *ir.Func, abiInfo *abi.ABIParamResultInfo) *obj.LSym {
  6811  	x := base.Ctxt.Lookup(fmt.Sprintf("%s.arginfo%d", f.LSym.Name, f.ABI))
  6812  	x.Align = 1
  6813  	// NOTE: do not set ContentAddressable here. This may be referenced from
  6814  	// assembly code by name (in this case f is a declaration).
  6815  	// Instead, set it in emitArgInfo above.
  6816  
  6817  	PtrSize := int64(types.PtrSize)
  6818  	uintptrTyp := types.Types[types.TUINTPTR]
  6819  
  6820  	isAggregate := func(t *types.Type) bool {
  6821  		return isStructNotSIMD(t) || t.IsArray() || t.IsComplex() || t.IsInterface() || t.IsString() || t.IsSlice()
  6822  	}
  6823  
  6824  	wOff := 0
  6825  	n := 0
  6826  	writebyte := func(o uint8) { wOff = objw.Uint8(x, wOff, o) }
  6827  
  6828  	// Write one non-aggregate arg/field/element.
  6829  	write1 := func(sz, offset int64) {
  6830  		if offset >= rtabi.TraceArgsSpecial {
  6831  			writebyte(rtabi.TraceArgsOffsetTooLarge)
  6832  		} else {
  6833  			writebyte(uint8(offset))
  6834  			writebyte(uint8(sz))
  6835  		}
  6836  		n++
  6837  	}
  6838  
  6839  	// Visit t recursively and write it out.
  6840  	// Returns whether to continue visiting.
  6841  	var visitType func(baseOffset int64, t *types.Type, depth int) bool
  6842  	visitType = func(baseOffset int64, t *types.Type, depth int) bool {
  6843  		if n >= rtabi.TraceArgsLimit {
  6844  			writebyte(rtabi.TraceArgsDotdotdot)
  6845  			return false
  6846  		}
  6847  		if !isAggregate(t) {
  6848  			write1(t.Size(), baseOffset)
  6849  			return true
  6850  		}
  6851  		writebyte(rtabi.TraceArgsStartAgg)
  6852  		depth++
  6853  		if depth >= rtabi.TraceArgsMaxDepth {
  6854  			writebyte(rtabi.TraceArgsDotdotdot)
  6855  			writebyte(rtabi.TraceArgsEndAgg)
  6856  			n++
  6857  			return true
  6858  		}
  6859  		switch {
  6860  		case t.IsInterface(), t.IsString():
  6861  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6862  				visitType(baseOffset+PtrSize, uintptrTyp, depth)
  6863  		case t.IsSlice():
  6864  			_ = visitType(baseOffset, uintptrTyp, depth) &&
  6865  				visitType(baseOffset+PtrSize, uintptrTyp, depth) &&
  6866  				visitType(baseOffset+PtrSize*2, uintptrTyp, depth)
  6867  		case t.IsComplex():
  6868  			_ = visitType(baseOffset, types.FloatForComplex(t), depth) &&
  6869  				visitType(baseOffset+t.Size()/2, types.FloatForComplex(t), depth)
  6870  		case t.IsArray():
  6871  			if t.NumElem() == 0 {
  6872  				n++ // {} counts as a component
  6873  				break
  6874  			}
  6875  			for i := int64(0); i < t.NumElem(); i++ {
  6876  				if !visitType(baseOffset, t.Elem(), depth) {
  6877  					break
  6878  				}
  6879  				baseOffset += t.Elem().Size()
  6880  			}
  6881  		case isStructNotSIMD(t):
  6882  			if t.NumFields() == 0 {
  6883  				n++ // {} counts as a component
  6884  				break
  6885  			}
  6886  			for _, field := range t.Fields() {
  6887  				if !visitType(baseOffset+field.Offset, field.Type, depth) {
  6888  					break
  6889  				}
  6890  			}
  6891  		}
  6892  		writebyte(rtabi.TraceArgsEndAgg)
  6893  		return true
  6894  	}
  6895  
  6896  	start := 0
  6897  	if strings.Contains(f.LSym.Name, "[") {
  6898  		// Skip the dictionary argument - it is implicit and the user doesn't need to see it.
  6899  		start = 1
  6900  	}
  6901  
  6902  	for _, a := range abiInfo.InParams()[start:] {
  6903  		if !visitType(a.FrameOffset(abiInfo), a.Type, 0) {
  6904  			break
  6905  		}
  6906  	}
  6907  	writebyte(rtabi.TraceArgsEndSeq)
  6908  	if wOff > rtabi.TraceArgsMaxLen {
  6909  		base.Fatalf("ArgInfo too large")
  6910  	}
  6911  
  6912  	return x
  6913  }
  6914  
  6915  // for wrapper, emit info of wrapped function.
  6916  func emitWrappedFuncInfo(e *ssafn, pp *objw.Progs) {
  6917  	if base.Ctxt.Flag_linkshared {
  6918  		// Relative reference (SymPtrOff) to another shared object doesn't work.
  6919  		// Unfortunate.
  6920  		return
  6921  	}
  6922  
  6923  	wfn := e.curfn.WrappedFunc
  6924  	if wfn == nil {
  6925  		return
  6926  	}
  6927  
  6928  	wsym := wfn.Linksym()
  6929  	x := base.Ctxt.LookupInit(fmt.Sprintf("%s.wrapinfo", wsym.Name), func(x *obj.LSym) {
  6930  		objw.SymPtrOff(x, 0, wsym)
  6931  		x.Set(obj.AttrContentAddressable, true)
  6932  		x.Align = 4
  6933  	})
  6934  	e.curfn.LSym.Func().WrapInfo = x
  6935  
  6936  	// Emit a funcdata pointing at the wrap info data.
  6937  	p := pp.Prog(obj.AFUNCDATA)
  6938  	p.From.SetConst(rtabi.FUNCDATA_WrapInfo)
  6939  	p.To.Type = obj.TYPE_MEM
  6940  	p.To.Name = obj.NAME_EXTERN
  6941  	p.To.Sym = x
  6942  }
  6943  
  6944  // genssa appends entries to pp for each instruction in f.
  6945  func genssa(f *ssa.Func, pp *objw.Progs) {
  6946  	var s State
  6947  	s.ABI = f.OwnAux.Fn.ABI()
  6948  
  6949  	e := f.Frontend().(*ssafn)
  6950  
  6951  	gatherPrintInfo := f.PrintOrHtmlSSA || ssa.GenssaDump[f.Name]
  6952  
  6953  	var lv *liveness.Liveness
  6954  	s.livenessMap, s.partLiveArgs, lv = liveness.Compute(e.curfn, f, e.stkptrsize, pp, gatherPrintInfo)
  6955  	emitArgInfo(e, f, pp)
  6956  	argLiveBlockMap, argLiveValueMap := liveness.ArgLiveness(e.curfn, f, pp)
  6957  
  6958  	openDeferInfo := e.curfn.LSym.Func().OpenCodedDeferInfo
  6959  	if openDeferInfo != nil {
  6960  		// This function uses open-coded defers -- write out the funcdata
  6961  		// info that we computed at the end of genssa.
  6962  		p := pp.Prog(obj.AFUNCDATA)
  6963  		p.From.SetConst(rtabi.FUNCDATA_OpenCodedDeferInfo)
  6964  		p.To.Type = obj.TYPE_MEM
  6965  		p.To.Name = obj.NAME_EXTERN
  6966  		p.To.Sym = openDeferInfo
  6967  	}
  6968  
  6969  	emitWrappedFuncInfo(e, pp)
  6970  
  6971  	// Remember where each block starts.
  6972  	s.bstart = make([]*obj.Prog, f.NumBlocks())
  6973  	s.pp = pp
  6974  	var progToValue map[*obj.Prog]*ssa.Value
  6975  	var progToBlock map[*obj.Prog]*ssa.Block
  6976  	var valueToProgAfter []*obj.Prog // The first Prog following computation of a value v; v is visible at this point.
  6977  	if gatherPrintInfo {
  6978  		progToValue = make(map[*obj.Prog]*ssa.Value, f.NumValues())
  6979  		progToBlock = make(map[*obj.Prog]*ssa.Block, f.NumBlocks())
  6980  		f.Logf("genssa %s\n", f.Name)
  6981  		progToBlock[s.pp.Next] = f.Blocks[0]
  6982  	}
  6983  
  6984  	if base.Ctxt.Flag_locationlists {
  6985  		if cap(f.Cache.ValueToProgAfter) < f.NumValues() {
  6986  			f.Cache.ValueToProgAfter = make([]*obj.Prog, f.NumValues())
  6987  		}
  6988  		valueToProgAfter = f.Cache.ValueToProgAfter[:f.NumValues()]
  6989  		clear(valueToProgAfter)
  6990  	}
  6991  
  6992  	// If the very first instruction is not tagged as a statement,
  6993  	// debuggers may attribute it to previous function in program.
  6994  	firstPos := src.NoXPos
  6995  	for _, v := range f.Entry.Values {
  6996  		if v.Pos.IsStmt() == src.PosIsStmt && v.Op != ssa.OpArg && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  6997  			firstPos = v.Pos
  6998  			v.Pos = firstPos.WithDefaultStmt()
  6999  			break
  7000  		}
  7001  	}
  7002  
  7003  	// inlMarks has an entry for each Prog that implements an inline mark.
  7004  	// It maps from that Prog to the global inlining id of the inlined body
  7005  	// which should unwind to this Prog's location.
  7006  	var inlMarks map[*obj.Prog]int32
  7007  	var inlMarkList []*obj.Prog
  7008  
  7009  	// inlMarksByPos maps from a (column 1) source position to the set of
  7010  	// Progs that are in the set above and have that source position.
  7011  	var inlMarksByPos map[src.XPos][]*obj.Prog
  7012  
  7013  	var argLiveIdx int = -1 // argument liveness info index
  7014  
  7015  	// These control cache line alignment; if the required portion of
  7016  	// a cache line is not available, then pad to obtain cache line
  7017  	// alignment.  Not implemented on all architectures, may not be
  7018  	// useful on all architectures.
  7019  	var hotAlign, hotRequire int64
  7020  
  7021  	if base.Debug.AlignHot > 0 {
  7022  		switch base.Ctxt.Arch.Name {
  7023  		// enable this on a case-by-case basis, with benchmarking.
  7024  		// currently shown:
  7025  		//   good for amd64
  7026  		//   not helpful for Apple Silicon
  7027  		//
  7028  		case "amd64", "386":
  7029  			// Align to 64 if 31 or fewer bytes remain in a cache line
  7030  			// benchmarks a little better than always aligning, and also
  7031  			// adds slightly less to the (PGO-compiled) binary size.
  7032  			hotAlign = 64
  7033  			hotRequire = 31
  7034  		}
  7035  	}
  7036  
  7037  	// Emit basic blocks
  7038  	for i, b := range f.Blocks {
  7039  
  7040  		s.lineRunStart = nil
  7041  		s.SetPos(s.pp.Pos.WithNotStmt()) // It needs a non-empty Pos, but cannot be a statement boundary (yet).
  7042  
  7043  		if hotAlign > 0 && b.Hotness&ssa.HotPgoInitial == ssa.HotPgoInitial {
  7044  			// So far this has only been shown profitable for PGO-hot loop headers.
  7045  			// The Hotness values allows distinctions between initial blocks that are "hot" or not, and "flow-in" or not.
  7046  			// Currently only the initial blocks of loops are tagged in this way;
  7047  			// there are no blocks tagged "pgo-hot" that are not also tagged "initial".
  7048  			// TODO more heuristics, more architectures.
  7049  			p := s.pp.Prog(obj.APCALIGNMAX)
  7050  			p.From.SetConst(hotAlign)
  7051  			p.To.SetConst(hotRequire)
  7052  		}
  7053  
  7054  		s.bstart[b.ID] = s.pp.Next
  7055  
  7056  		if idx, ok := argLiveBlockMap[b.ID]; ok && idx != argLiveIdx {
  7057  			argLiveIdx = idx
  7058  			p := s.pp.Prog(obj.APCDATA)
  7059  			p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  7060  			p.To.SetConst(int64(idx))
  7061  		}
  7062  
  7063  		// Emit values in block
  7064  		Arch.SSAMarkMoves(&s, b)
  7065  		for _, v := range b.Values {
  7066  			x := s.pp.Next
  7067  			s.DebugFriendlySetPosFrom(v)
  7068  
  7069  			if v.Op.ResultInArg0() && v.ResultReg() != v.Args[0].Reg() {
  7070  				v.Fatalf("input[0] and output not in same register %s", v.LongString())
  7071  			}
  7072  
  7073  			switch v.Op {
  7074  			case ssa.OpInitMem:
  7075  				// memory arg needs no code
  7076  			case ssa.OpArg:
  7077  				// input args need no code
  7078  			case ssa.OpSP, ssa.OpSB:
  7079  				// nothing to do
  7080  			case ssa.OpSelect0, ssa.OpSelect1, ssa.OpSelectN, ssa.OpMakeResult:
  7081  				// nothing to do
  7082  			case ssa.OpGetG:
  7083  				// nothing to do when there's a g register,
  7084  				// and checkLower complains if there's not
  7085  			case ssa.OpVarDef, ssa.OpVarLive, ssa.OpKeepAlive, ssa.OpWBend:
  7086  				// nothing to do; already used by liveness
  7087  			case ssa.OpPhi:
  7088  				CheckLoweredPhi(v)
  7089  			case ssa.OpConvert:
  7090  				// nothing to do; no-op conversion for liveness
  7091  				if v.Args[0].Reg() != v.Reg() {
  7092  					v.Fatalf("OpConvert should be a no-op: %s; %s", v.Args[0].LongString(), v.LongString())
  7093  				}
  7094  			case ssa.OpInlMark:
  7095  				p := Arch.Ginsnop(s.pp)
  7096  				if inlMarks == nil {
  7097  					inlMarks = map[*obj.Prog]int32{}
  7098  					inlMarksByPos = map[src.XPos][]*obj.Prog{}
  7099  				}
  7100  				inlMarks[p] = v.AuxInt32()
  7101  				inlMarkList = append(inlMarkList, p)
  7102  				pos := v.Pos.AtColumn1()
  7103  				inlMarksByPos[pos] = append(inlMarksByPos[pos], p)
  7104  				firstPos = src.NoXPos
  7105  
  7106  			default:
  7107  				// Special case for first line in function; move it to the start (which cannot be a register-valued instruction)
  7108  				if firstPos != src.NoXPos && v.Op != ssa.OpArgIntReg && v.Op != ssa.OpArgFloatReg && v.Op != ssa.OpLoadReg && v.Op != ssa.OpStoreReg {
  7109  					s.SetPos(firstPos)
  7110  					firstPos = src.NoXPos
  7111  				}
  7112  				// Attach this safe point to the next
  7113  				// instruction.
  7114  				s.pp.NextLive = s.livenessMap.Get(v)
  7115  				s.pp.NextUnsafe = s.livenessMap.GetUnsafe(v)
  7116  
  7117  				// let the backend handle it
  7118  				Arch.SSAGenValue(&s, v)
  7119  			}
  7120  
  7121  			if idx, ok := argLiveValueMap[v.ID]; ok && idx != argLiveIdx {
  7122  				argLiveIdx = idx
  7123  				p := s.pp.Prog(obj.APCDATA)
  7124  				p.From.SetConst(rtabi.PCDATA_ArgLiveIndex)
  7125  				p.To.SetConst(int64(idx))
  7126  			}
  7127  
  7128  			if base.Ctxt.Flag_locationlists {
  7129  				valueToProgAfter[v.ID] = s.pp.Next
  7130  			}
  7131  
  7132  			if gatherPrintInfo {
  7133  				for ; x != s.pp.Next; x = x.Link {
  7134  					progToValue[x] = v
  7135  				}
  7136  			}
  7137  		}
  7138  		// If this is an empty infinite loop, stick a hardware NOP in there so that debuggers are less confused.
  7139  		if s.bstart[b.ID] == s.pp.Next && len(b.Succs) == 1 && b.Succs[0].Block() == b {
  7140  			p := Arch.Ginsnop(s.pp)
  7141  			p.Pos = p.Pos.WithIsStmt()
  7142  			if b.Pos == src.NoXPos {
  7143  				b.Pos = p.Pos // It needs a file, otherwise a no-file non-zero line causes confusion.  See #35652.
  7144  				if b.Pos == src.NoXPos {
  7145  					b.Pos = s.pp.Text.Pos // Sometimes p.Pos is empty.  See #35695.
  7146  				}
  7147  			}
  7148  			b.Pos = b.Pos.WithBogusLine() // Debuggers are not good about infinite loops, force a change in line number
  7149  		}
  7150  
  7151  		// Set unsafe mark for any end-of-block generated instructions
  7152  		// (normally, conditional or unconditional branches).
  7153  		// This is particularly important for empty blocks, as there
  7154  		// are no values to inherit the unsafe mark from.
  7155  		s.pp.NextUnsafe = s.livenessMap.GetUnsafeBlock(b)
  7156  
  7157  		// Emit control flow instructions for block
  7158  		var next *ssa.Block
  7159  		if i < len(f.Blocks)-1 && base.Flag.N == 0 {
  7160  			// If -N, leave next==nil so every block with successors
  7161  			// ends in a JMP (except call blocks - plive doesn't like
  7162  			// select{send,recv} followed by a JMP call).  Helps keep
  7163  			// line numbers for otherwise empty blocks.
  7164  			next = f.Blocks[i+1]
  7165  		}
  7166  		x := s.pp.Next
  7167  		s.SetPos(b.Pos)
  7168  		Arch.SSAGenBlock(&s, b, next)
  7169  		if gatherPrintInfo {
  7170  			for ; x != s.pp.Next; x = x.Link {
  7171  				progToBlock[x] = b
  7172  			}
  7173  		}
  7174  	}
  7175  	if f.Blocks[len(f.Blocks)-1].Kind == ssa.BlockExit {
  7176  		// We need the return address of a panic call to
  7177  		// still be inside the function in question. So if
  7178  		// it ends in a call which doesn't return, add a
  7179  		// nop (which will never execute) after the call.
  7180  		Arch.Ginsnop(s.pp)
  7181  	}
  7182  	if openDeferInfo != nil {
  7183  		// When doing open-coded defers, generate a disconnected call to
  7184  		// deferreturn and a return. This will be used to during panic
  7185  		// recovery to unwind the stack and return back to the runtime.
  7186  
  7187  		// Note that this exit code doesn't work if a return parameter
  7188  		// is heap-allocated, but open defers aren't enabled in that case.
  7189  
  7190  		// TODO either make this handle heap-allocated return parameters or reuse the other-defers general-purpose code path.
  7191  		s.pp.NextLive = s.livenessMap.DeferReturn
  7192  		p := s.pp.Prog(obj.ACALL)
  7193  		p.To.Type = obj.TYPE_MEM
  7194  		p.To.Name = obj.NAME_EXTERN
  7195  		p.To.Sym = ir.Syms.Deferreturn
  7196  
  7197  		// Load results into registers. So when a deferred function
  7198  		// recovers a panic, it will return to caller with right results.
  7199  		// The results are already in memory, because they are not SSA'd
  7200  		// when the function has defers (see canSSAName).
  7201  		for _, o := range f.OwnAux.ABIInfo().OutParams() {
  7202  			n := o.Name
  7203  			rts, offs := o.RegisterTypesAndOffsets()
  7204  			for i := range o.Registers {
  7205  				Arch.LoadRegResult(&s, f, rts[i], ssa.ObjRegForAbiReg(o.Registers[i], f.Config), n, offs[i])
  7206  			}
  7207  		}
  7208  
  7209  		s.pp.Prog(obj.ARET)
  7210  	}
  7211  
  7212  	if inlMarks != nil {
  7213  		hasCall := false
  7214  
  7215  		// We have some inline marks. Try to find other instructions we're
  7216  		// going to emit anyway, and use those instructions instead of the
  7217  		// inline marks.
  7218  		for p := s.pp.Text; p != nil; p = p.Link {
  7219  			if p.As == obj.ANOP || p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT ||
  7220  				p.As == obj.APCALIGN || p.As == obj.APCALIGNMAX || Arch.LinkArch.Family == sys.Wasm {
  7221  				// Don't use 0-sized instructions as inline marks, because we need
  7222  				// to identify inline mark instructions by pc offset.
  7223  				// (Some of these instructions are sometimes zero-sized, sometimes not.
  7224  				// We must not use anything that even might be zero-sized.)
  7225  				// TODO: are there others?
  7226  				continue
  7227  			}
  7228  			if _, ok := inlMarks[p]; ok {
  7229  				// Don't use inline marks themselves. We don't know
  7230  				// whether they will be zero-sized or not yet.
  7231  				continue
  7232  			}
  7233  			if p.As == obj.ACALL || p.As == obj.ADUFFCOPY || p.As == obj.ADUFFZERO {
  7234  				hasCall = true
  7235  			}
  7236  			pos := p.Pos.AtColumn1()
  7237  			marks := inlMarksByPos[pos]
  7238  			if len(marks) == 0 {
  7239  				continue
  7240  			}
  7241  			for _, m := range marks {
  7242  				// We found an instruction with the same source position as
  7243  				// some of the inline marks.
  7244  				// Use this instruction instead.
  7245  				p.Pos = p.Pos.WithIsStmt() // promote position to a statement
  7246  				s.pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[m])
  7247  				// Make the inline mark a real nop, so it doesn't generate any code.
  7248  				m.As = obj.ANOP
  7249  				m.Pos = src.NoXPos
  7250  				m.From = obj.Addr{}
  7251  				m.To = obj.Addr{}
  7252  			}
  7253  			delete(inlMarksByPos, pos)
  7254  		}
  7255  		// Any unmatched inline marks now need to be added to the inlining tree (and will generate a nop instruction).
  7256  		for _, p := range inlMarkList {
  7257  			if p.As != obj.ANOP {
  7258  				s.pp.CurFunc.LSym.Func().AddInlMark(p, inlMarks[p])
  7259  			}
  7260  		}
  7261  
  7262  		if e.stksize == 0 && !hasCall {
  7263  			// Frameless leaf function. It doesn't need any preamble,
  7264  			// so make sure its first instruction isn't from an inlined callee.
  7265  			// If it is, add a nop at the start of the function with a position
  7266  			// equal to the start of the function.
  7267  			// This ensures that runtime.FuncForPC(uintptr(reflect.ValueOf(fn).Pointer())).Name()
  7268  			// returns the right answer. See issue 58300.
  7269  			for p := s.pp.Text; p != nil; p = p.Link {
  7270  				if p.As == obj.AFUNCDATA || p.As == obj.APCDATA || p.As == obj.ATEXT || p.As == obj.ANOP {
  7271  					continue
  7272  				}
  7273  				if base.Ctxt.PosTable.Pos(p.Pos).Base().InliningIndex() >= 0 {
  7274  					// Make a real (not 0-sized) nop.
  7275  					nop := Arch.Ginsnop(s.pp)
  7276  					nop.Pos = e.curfn.Pos().WithIsStmt()
  7277  
  7278  					// Unfortunately, Ginsnop puts the instruction at the
  7279  					// end of the list. Move it up to just before p.
  7280  
  7281  					// Unlink from the current list.
  7282  					for x := s.pp.Text; x != nil; x = x.Link {
  7283  						if x.Link == nop {
  7284  							x.Link = nop.Link
  7285  							break
  7286  						}
  7287  					}
  7288  					// Splice in right before p.
  7289  					for x := s.pp.Text; x != nil; x = x.Link {
  7290  						if x.Link == p {
  7291  							nop.Link = p
  7292  							x.Link = nop
  7293  							break
  7294  						}
  7295  					}
  7296  				}
  7297  				break
  7298  			}
  7299  		}
  7300  	}
  7301  
  7302  	if base.Ctxt.Flag_locationlists {
  7303  		var debugInfo *ssa.FuncDebug
  7304  		debugInfo = e.curfn.DebugInfo.(*ssa.FuncDebug)
  7305  		// Save off entry ID in case we need it later for DWARF generation
  7306  		// for return values promoted to the heap.
  7307  		debugInfo.EntryID = f.Entry.ID
  7308  		if e.curfn.ABI == obj.ABIInternal && base.Flag.N != 0 {
  7309  			ssa.BuildFuncDebugNoOptimized(base.Ctxt, f, base.Debug.LocationLists > 1, StackOffset, debugInfo)
  7310  		} else {
  7311  			ssa.BuildFuncDebug(base.Ctxt, f, base.Debug.LocationLists, StackOffset, debugInfo)
  7312  		}
  7313  		bstart := s.bstart
  7314  		idToIdx := make([]int, f.NumBlocks())
  7315  		for i, b := range f.Blocks {
  7316  			idToIdx[b.ID] = i
  7317  		}
  7318  		// Register a callback that will be used later to fill in PCs into location
  7319  		// lists. At the moment, Prog.Pc is a sequence number; it's not a real PC
  7320  		// until after assembly, so the translation needs to be deferred.
  7321  		debugInfo.GetPC = func(b, v ssa.ID) int64 {
  7322  			switch v {
  7323  			case ssa.BlockStart.ID:
  7324  				if b == f.Entry.ID {
  7325  					return 0 // Start at the very beginning, at the assembler-generated prologue.
  7326  					// this should only happen for function args (ssa.OpArg)
  7327  				}
  7328  				return bstart[b].Pc
  7329  			case ssa.BlockEnd.ID:
  7330  				blk := f.Blocks[idToIdx[b]]
  7331  				nv := len(blk.Values)
  7332  				return valueToProgAfter[blk.Values[nv-1].ID].Pc
  7333  			case ssa.FuncEnd.ID:
  7334  				return e.curfn.LSym.Size
  7335  			default:
  7336  				return valueToProgAfter[v].Pc
  7337  			}
  7338  		}
  7339  	}
  7340  
  7341  	// Resolve branches, and relax DefaultStmt into NotStmt
  7342  	for _, br := range s.Branches {
  7343  		br.P.To.SetTarget(s.bstart[br.B.ID])
  7344  		if br.P.Pos.IsStmt() != src.PosIsStmt {
  7345  			br.P.Pos = br.P.Pos.WithNotStmt()
  7346  		} else if v0 := br.B.FirstPossibleStmtValue(); v0 != nil && v0.Pos.Line() == br.P.Pos.Line() && v0.Pos.IsStmt() == src.PosIsStmt {
  7347  			br.P.Pos = br.P.Pos.WithNotStmt()
  7348  		}
  7349  
  7350  	}
  7351  
  7352  	// Resolve jump table destinations.
  7353  	for _, jt := range s.JumpTables {
  7354  		// Convert from *Block targets to *Prog targets.
  7355  		targets := make([]*obj.Prog, len(jt.Succs))
  7356  		for i, e := range jt.Succs {
  7357  			targets[i] = s.bstart[e.Block().ID]
  7358  		}
  7359  		// Add to list of jump tables to be resolved at assembly time.
  7360  		// The assembler converts from *Prog entries to absolute addresses
  7361  		// once it knows instruction byte offsets.
  7362  		fi := s.pp.CurFunc.LSym.Func()
  7363  		fi.JumpTables = append(fi.JumpTables, obj.JumpTable{Sym: jt.Aux.(*obj.LSym), Targets: targets})
  7364  	}
  7365  
  7366  	if e.log { // spew to stdout
  7367  		filename := ""
  7368  		for p := s.pp.Text; p != nil; p = p.Link {
  7369  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7370  				filename = p.InnermostFilename()
  7371  				f.Logf("# %s\n", filename)
  7372  			}
  7373  
  7374  			var s string
  7375  			if v, ok := progToValue[p]; ok {
  7376  				s = v.String()
  7377  			} else if b, ok := progToBlock[p]; ok {
  7378  				s = b.String()
  7379  			} else {
  7380  				s = "   " // most value and branch strings are 2-3 characters long
  7381  			}
  7382  			f.Logf(" %-6s\t%.5d (%s)\t%s\n", s, p.Pc, p.InnermostLineNumber(), p.InstructionString())
  7383  		}
  7384  	}
  7385  	if f.HTMLWriter != nil { // spew to ssa.html
  7386  		var buf strings.Builder
  7387  		buf.WriteString("<code>")
  7388  		buf.WriteString("<dl class=\"ssa-gen\">")
  7389  		filename := ""
  7390  
  7391  		liveness := lv.Format(nil)
  7392  		if liveness != "" {
  7393  			buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7394  			buf.WriteString(html.EscapeString("# " + liveness))
  7395  			buf.WriteString("</dd>")
  7396  		}
  7397  
  7398  		for p := s.pp.Text; p != nil; p = p.Link {
  7399  			// Don't spam every line with the file name, which is often huge.
  7400  			// Only print changes, and "unknown" is not a change.
  7401  			if p.Pos.IsKnown() && p.InnermostFilename() != filename {
  7402  				filename = p.InnermostFilename()
  7403  				buf.WriteString("<dt class=\"ssa-prog-src\"></dt><dd class=\"ssa-prog\">")
  7404  				buf.WriteString(html.EscapeString("# " + filename))
  7405  				buf.WriteString("</dd>")
  7406  			}
  7407  
  7408  			buf.WriteString("<dt class=\"ssa-prog-src\">")
  7409  			if v, ok := progToValue[p]; ok {
  7410  
  7411  				// Prefix calls with their liveness, if any
  7412  				if p.As != obj.APCDATA {
  7413  					if liveness := lv.Format(v); liveness != "" {
  7414  						// Steal this line, and restart a line
  7415  						buf.WriteString("</dt><dd class=\"ssa-prog\">")
  7416  						buf.WriteString(html.EscapeString("# " + liveness))
  7417  						buf.WriteString("</dd>")
  7418  						// restarting a line
  7419  						buf.WriteString("<dt class=\"ssa-prog-src\">")
  7420  					}
  7421  				}
  7422  
  7423  				buf.WriteString(v.HTML())
  7424  			} else if b, ok := progToBlock[p]; ok {
  7425  				buf.WriteString("<b>" + b.HTML() + "</b>")
  7426  			}
  7427  			buf.WriteString("</dt>")
  7428  			buf.WriteString("<dd class=\"ssa-prog\">")
  7429  			fmt.Fprintf(&buf, "%.5d <span class=\"l%v line-number\">(%s)</span> %s", p.Pc, p.InnermostLineNumber(), p.InnermostLineNumberHTML(), html.EscapeString(p.InstructionString()))
  7430  			buf.WriteString("</dd>")
  7431  		}
  7432  		buf.WriteString("</dl>")
  7433  		buf.WriteString("</code>")
  7434  		f.HTMLWriter.WriteColumn("genssa", "genssa", "ssa-prog", buf.String())
  7435  	}
  7436  	if ssa.GenssaDump[f.Name] {
  7437  		fi := f.DumpFileForPhase("genssa")
  7438  		if fi != nil {
  7439  
  7440  			// inliningDiffers if any filename changes or if any line number except the innermost (last index) changes.
  7441  			inliningDiffers := func(a, b []src.Pos) bool {
  7442  				if len(a) != len(b) {
  7443  					return true
  7444  				}
  7445  				for i := range a {
  7446  					if a[i].Filename() != b[i].Filename() {
  7447  						return true
  7448  					}
  7449  					if i != len(a)-1 && a[i].Line() != b[i].Line() {
  7450  						return true
  7451  					}
  7452  				}
  7453  				return false
  7454  			}
  7455  
  7456  			var allPosOld []src.Pos
  7457  			var allPos []src.Pos
  7458  
  7459  			for p := s.pp.Text; p != nil; p = p.Link {
  7460  				if p.Pos.IsKnown() {
  7461  					allPos = allPos[:0]
  7462  					p.Ctxt.AllPos(p.Pos, func(pos src.Pos) { allPos = append(allPos, pos) })
  7463  					if inliningDiffers(allPos, allPosOld) {
  7464  						for _, pos := range allPos {
  7465  							fmt.Fprintf(fi, "# %s:%d\n", pos.Filename(), pos.Line())
  7466  						}
  7467  						allPos, allPosOld = allPosOld, allPos // swap, not copy, so that they do not share slice storage.
  7468  					}
  7469  				}
  7470  
  7471  				var s string
  7472  				if v, ok := progToValue[p]; ok {
  7473  					s = v.String()
  7474  				} else if b, ok := progToBlock[p]; ok {
  7475  					s = b.String()
  7476  				} else {
  7477  					s = "   " // most value and branch strings are 2-3 characters long
  7478  				}
  7479  				fmt.Fprintf(fi, " %-6s\t%.5d %s\t%s\n", s, p.Pc, ssa.StmtString(p.Pos), p.InstructionString())
  7480  			}
  7481  			fi.Close()
  7482  		}
  7483  	}
  7484  
  7485  	defframe(&s, e, f)
  7486  
  7487  	f.HTMLWriter.Close()
  7488  	f.HTMLWriter = nil
  7489  }
  7490  
  7491  func defframe(s *State, e *ssafn, f *ssa.Func) {
  7492  	pp := s.pp
  7493  
  7494  	s.maxarg = types.RoundUp(s.maxarg, e.stkalign)
  7495  	frame := s.maxarg + e.stksize
  7496  	if Arch.PadFrame != nil {
  7497  		frame = Arch.PadFrame(frame)
  7498  	}
  7499  
  7500  	// Fill in argument and frame size.
  7501  	pp.Text.To.Type = obj.TYPE_TEXTSIZE
  7502  	pp.Text.To.Val = int32(types.RoundUp(f.OwnAux.ArgWidth(), int64(types.RegSize)))
  7503  	pp.Text.To.Offset = frame
  7504  
  7505  	p := pp.Text
  7506  
  7507  	// Insert code to spill argument registers if the named slot may be partially
  7508  	// live. That is, the named slot is considered live by liveness analysis,
  7509  	// (because a part of it is live), but we may not spill all parts into the
  7510  	// slot. This can only happen with aggregate-typed arguments that are SSA-able
  7511  	// and not address-taken (for non-SSA-able or address-taken arguments we always
  7512  	// spill upfront).
  7513  	// Note: spilling is unnecessary in the -N/no-optimize case, since all values
  7514  	// will be considered non-SSAable and spilled up front.
  7515  	// TODO(register args) Make liveness more fine-grained to that partial spilling is okay.
  7516  	if f.OwnAux.ABIInfo().InRegistersUsed() != 0 && base.Flag.N == 0 {
  7517  		// First, see if it is already spilled before it may be live. Look for a spill
  7518  		// in the entry block up to the first safepoint.
  7519  		type nameOff struct {
  7520  			n   *ir.Name
  7521  			off int64
  7522  		}
  7523  		partLiveArgsSpilled := make(map[nameOff]bool)
  7524  		for _, v := range f.Entry.Values {
  7525  			if v.Op.IsCall() {
  7526  				break
  7527  			}
  7528  			if v.Op != ssa.OpStoreReg || v.Args[0].Op != ssa.OpArgIntReg {
  7529  				continue
  7530  			}
  7531  			n, off := ssa.AutoVar(v)
  7532  			if n.Class != ir.PPARAM || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] {
  7533  				continue
  7534  			}
  7535  			partLiveArgsSpilled[nameOff{n, off}] = true
  7536  		}
  7537  
  7538  		// Then, insert code to spill registers if not already.
  7539  		for _, a := range f.OwnAux.ABIInfo().InParams() {
  7540  			n := a.Name
  7541  			if n == nil || n.Addrtaken() || !ssa.CanSSA(n.Type()) || !s.partLiveArgs[n] || len(a.Registers) <= 1 {
  7542  				continue
  7543  			}
  7544  			rts, offs := a.RegisterTypesAndOffsets()
  7545  			for i := range a.Registers {
  7546  				if !rts[i].HasPointers() {
  7547  					continue
  7548  				}
  7549  				if partLiveArgsSpilled[nameOff{n, offs[i]}] {
  7550  					continue // already spilled
  7551  				}
  7552  				reg := ssa.ObjRegForAbiReg(a.Registers[i], f.Config)
  7553  				p = Arch.SpillArgReg(pp, p, f, rts[i], reg, n, offs[i])
  7554  			}
  7555  		}
  7556  	}
  7557  
  7558  	// Insert code to zero ambiguously live variables so that the
  7559  	// garbage collector only sees initialized values when it
  7560  	// looks for pointers.
  7561  	var lo, hi int64
  7562  
  7563  	// Opaque state for backend to use. Current backends use it to
  7564  	// keep track of which helper registers have been zeroed.
  7565  	var state uint32
  7566  
  7567  	// Iterate through declarations. Autos are sorted in decreasing
  7568  	// frame offset order.
  7569  	for _, n := range e.curfn.Dcl {
  7570  		if !n.Needzero() {
  7571  			continue
  7572  		}
  7573  		if n.Class != ir.PAUTO {
  7574  			e.Fatalf(n.Pos(), "needzero class %d", n.Class)
  7575  		}
  7576  		if n.Type().Size()%int64(types.PtrSize) != 0 || n.FrameOffset()%int64(types.PtrSize) != 0 || n.Type().Size() == 0 {
  7577  			e.Fatalf(n.Pos(), "var %L has size %d offset %d", n, n.Type().Size(), n.Offset_)
  7578  		}
  7579  
  7580  		if lo != hi && n.FrameOffset()+n.Type().Size() >= lo-int64(2*types.RegSize) {
  7581  			// Merge with range we already have.
  7582  			lo = n.FrameOffset()
  7583  			continue
  7584  		}
  7585  
  7586  		// Zero old range
  7587  		p = Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7588  
  7589  		// Set new range.
  7590  		lo = n.FrameOffset()
  7591  		hi = lo + n.Type().Size()
  7592  	}
  7593  
  7594  	// Zero final range.
  7595  	Arch.ZeroRange(pp, p, frame+lo, hi-lo, &state)
  7596  }
  7597  
  7598  // For generating consecutive jump instructions to model a specific branching
  7599  type IndexJump struct {
  7600  	Jump  obj.As
  7601  	Index int
  7602  }
  7603  
  7604  func (s *State) oneJump(b *ssa.Block, jump *IndexJump) {
  7605  	p := s.Br(jump.Jump, b.Succs[jump.Index].Block())
  7606  	p.Pos = b.Pos
  7607  }
  7608  
  7609  // CombJump generates combinational instructions (2 at present) for a block jump,
  7610  // thereby the behaviour of non-standard condition codes could be simulated
  7611  func (s *State) CombJump(b, next *ssa.Block, jumps *[2][2]IndexJump) {
  7612  	switch next {
  7613  	case b.Succs[0].Block():
  7614  		s.oneJump(b, &jumps[0][0])
  7615  		s.oneJump(b, &jumps[0][1])
  7616  	case b.Succs[1].Block():
  7617  		s.oneJump(b, &jumps[1][0])
  7618  		s.oneJump(b, &jumps[1][1])
  7619  	default:
  7620  		var q *obj.Prog
  7621  		if b.Likely != ssa.BranchUnlikely {
  7622  			s.oneJump(b, &jumps[1][0])
  7623  			s.oneJump(b, &jumps[1][1])
  7624  			q = s.Br(obj.AJMP, b.Succs[1].Block())
  7625  		} else {
  7626  			s.oneJump(b, &jumps[0][0])
  7627  			s.oneJump(b, &jumps[0][1])
  7628  			q = s.Br(obj.AJMP, b.Succs[0].Block())
  7629  		}
  7630  		q.Pos = b.Pos
  7631  	}
  7632  }
  7633  
  7634  // AddAux adds the offset in the aux fields (AuxInt and Aux) of v to a.
  7635  func AddAux(a *obj.Addr, v *ssa.Value) {
  7636  	AddAux2(a, v, v.AuxInt)
  7637  }
  7638  func AddAux2(a *obj.Addr, v *ssa.Value, offset int64) {
  7639  	if a.Type != obj.TYPE_MEM && a.Type != obj.TYPE_ADDR {
  7640  		v.Fatalf("bad AddAux addr %v", a)
  7641  	}
  7642  	// add integer offset
  7643  	a.Offset += offset
  7644  
  7645  	// If no additional symbol offset, we're done.
  7646  	if v.Aux == nil {
  7647  		return
  7648  	}
  7649  	// Add symbol's offset from its base register.
  7650  	switch n := v.Aux.(type) {
  7651  	case *ssa.AuxCall:
  7652  		a.Name = obj.NAME_EXTERN
  7653  		a.Sym = n.Fn
  7654  	case *obj.LSym:
  7655  		a.Name = obj.NAME_EXTERN
  7656  		a.Sym = n
  7657  	case *ir.Name:
  7658  		if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7659  			a.Name = obj.NAME_PARAM
  7660  		} else {
  7661  			a.Name = obj.NAME_AUTO
  7662  		}
  7663  		a.Sym = n.Linksym()
  7664  		a.Offset += n.FrameOffset()
  7665  	default:
  7666  		v.Fatalf("aux in %s not implemented %#v", v, v.Aux)
  7667  	}
  7668  }
  7669  
  7670  // extendIndex extends v to a full int width.
  7671  // panic with the given kind if v does not fit in an int (only on 32-bit archs).
  7672  func (s *state) extendIndex(idx, len *ssa.Value, kind ssa.BoundsKind, bounded bool) *ssa.Value {
  7673  	size := idx.Type.Size()
  7674  	if size == s.config.PtrSize {
  7675  		return idx
  7676  	}
  7677  	if size > s.config.PtrSize {
  7678  		// truncate 64-bit indexes on 32-bit pointer archs. Test the
  7679  		// high word and branch to out-of-bounds failure if it is not 0.
  7680  		var lo *ssa.Value
  7681  		if idx.Type.IsSigned() {
  7682  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TINT], idx)
  7683  		} else {
  7684  			lo = s.newValue1(ssa.OpInt64Lo, types.Types[types.TUINT], idx)
  7685  		}
  7686  		if bounded || base.Flag.B != 0 {
  7687  			return lo
  7688  		}
  7689  		bNext := s.f.NewBlock(ssa.BlockPlain)
  7690  		bPanic := s.f.NewBlock(ssa.BlockExit)
  7691  		hi := s.newValue1(ssa.OpInt64Hi, types.Types[types.TUINT32], idx)
  7692  		cmp := s.newValue2(ssa.OpEq32, types.Types[types.TBOOL], hi, s.constInt32(types.Types[types.TUINT32], 0))
  7693  		if !idx.Type.IsSigned() {
  7694  			switch kind {
  7695  			case ssa.BoundsIndex:
  7696  				kind = ssa.BoundsIndexU
  7697  			case ssa.BoundsSliceAlen:
  7698  				kind = ssa.BoundsSliceAlenU
  7699  			case ssa.BoundsSliceAcap:
  7700  				kind = ssa.BoundsSliceAcapU
  7701  			case ssa.BoundsSliceB:
  7702  				kind = ssa.BoundsSliceBU
  7703  			case ssa.BoundsSlice3Alen:
  7704  				kind = ssa.BoundsSlice3AlenU
  7705  			case ssa.BoundsSlice3Acap:
  7706  				kind = ssa.BoundsSlice3AcapU
  7707  			case ssa.BoundsSlice3B:
  7708  				kind = ssa.BoundsSlice3BU
  7709  			case ssa.BoundsSlice3C:
  7710  				kind = ssa.BoundsSlice3CU
  7711  			}
  7712  		}
  7713  		b := s.endBlock()
  7714  		b.Kind = ssa.BlockIf
  7715  		b.SetControl(cmp)
  7716  		b.Likely = ssa.BranchLikely
  7717  		b.AddEdgeTo(bNext)
  7718  		b.AddEdgeTo(bPanic)
  7719  
  7720  		s.startBlock(bPanic)
  7721  		mem := s.newValue4I(ssa.OpPanicExtend, types.TypeMem, int64(kind), hi, lo, len, s.mem())
  7722  		s.endBlock().SetControl(mem)
  7723  		s.startBlock(bNext)
  7724  
  7725  		return lo
  7726  	}
  7727  
  7728  	// Extend value to the required size
  7729  	var op ssa.Op
  7730  	if idx.Type.IsSigned() {
  7731  		switch 10*size + s.config.PtrSize {
  7732  		case 14:
  7733  			op = ssa.OpSignExt8to32
  7734  		case 18:
  7735  			op = ssa.OpSignExt8to64
  7736  		case 24:
  7737  			op = ssa.OpSignExt16to32
  7738  		case 28:
  7739  			op = ssa.OpSignExt16to64
  7740  		case 48:
  7741  			op = ssa.OpSignExt32to64
  7742  		default:
  7743  			s.Fatalf("bad signed index extension %s", idx.Type)
  7744  		}
  7745  	} else {
  7746  		switch 10*size + s.config.PtrSize {
  7747  		case 14:
  7748  			op = ssa.OpZeroExt8to32
  7749  		case 18:
  7750  			op = ssa.OpZeroExt8to64
  7751  		case 24:
  7752  			op = ssa.OpZeroExt16to32
  7753  		case 28:
  7754  			op = ssa.OpZeroExt16to64
  7755  		case 48:
  7756  			op = ssa.OpZeroExt32to64
  7757  		default:
  7758  			s.Fatalf("bad unsigned index extension %s", idx.Type)
  7759  		}
  7760  	}
  7761  	return s.newValue1(op, types.Types[types.TINT], idx)
  7762  }
  7763  
  7764  // CheckLoweredPhi checks that regalloc and stackalloc correctly handled phi values.
  7765  // Called during ssaGenValue.
  7766  func CheckLoweredPhi(v *ssa.Value) {
  7767  	if v.Op != ssa.OpPhi {
  7768  		v.Fatalf("CheckLoweredPhi called with non-phi value: %v", v.LongString())
  7769  	}
  7770  	if v.Type.IsMemory() {
  7771  		return
  7772  	}
  7773  	f := v.Block.Func
  7774  	loc := f.RegAlloc[v.ID]
  7775  	for _, a := range v.Args {
  7776  		if aloc := f.RegAlloc[a.ID]; aloc != loc { // TODO: .Equal() instead?
  7777  			v.Fatalf("phi arg at different location than phi: %v @ %s, but arg %v @ %s\n%s\n", v, loc, a, aloc, v.Block.Func)
  7778  		}
  7779  	}
  7780  }
  7781  
  7782  // CheckLoweredGetClosurePtr checks that v is the first instruction in the function's entry block,
  7783  // except for incoming in-register arguments.
  7784  // The output of LoweredGetClosurePtr is generally hardwired to the correct register.
  7785  // That register contains the closure pointer on closure entry.
  7786  func CheckLoweredGetClosurePtr(v *ssa.Value) {
  7787  	entry := v.Block.Func.Entry
  7788  	if entry != v.Block {
  7789  		base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7790  	}
  7791  	for _, w := range entry.Values {
  7792  		if w == v {
  7793  			break
  7794  		}
  7795  		switch w.Op {
  7796  		case ssa.OpArgIntReg, ssa.OpArgFloatReg:
  7797  			// okay
  7798  		default:
  7799  			base.Fatalf("in %s, badly placed LoweredGetClosurePtr: %v %v", v.Block.Func.Name, v.Block, v)
  7800  		}
  7801  	}
  7802  }
  7803  
  7804  // CheckArgReg ensures that v is in the function's entry block.
  7805  func CheckArgReg(v *ssa.Value) {
  7806  	entry := v.Block.Func.Entry
  7807  	if entry != v.Block {
  7808  		base.Fatalf("in %s, badly placed ArgIReg or ArgFReg: %v %v", v.Block.Func.Name, v.Block, v)
  7809  	}
  7810  }
  7811  
  7812  func AddrAuto(a *obj.Addr, v *ssa.Value) {
  7813  	n, off := ssa.AutoVar(v)
  7814  	a.Type = obj.TYPE_MEM
  7815  	a.Sym = n.Linksym()
  7816  	a.Reg = int16(Arch.REGSP)
  7817  	a.Offset = n.FrameOffset() + off
  7818  	if n.Class == ir.PPARAM || (n.Class == ir.PPARAMOUT && !n.IsOutputParamInRegisters()) {
  7819  		a.Name = obj.NAME_PARAM
  7820  	} else {
  7821  		a.Name = obj.NAME_AUTO
  7822  	}
  7823  }
  7824  
  7825  // Call returns a new CALL instruction for the SSA value v.
  7826  // It uses PrepareCall to prepare the call.
  7827  func (s *State) Call(v *ssa.Value) *obj.Prog {
  7828  	pPosIsStmt := s.pp.Pos.IsStmt() // The statement-ness of the call comes from ssaGenState
  7829  	s.PrepareCall(v)
  7830  
  7831  	p := s.Prog(obj.ACALL)
  7832  	if pPosIsStmt == src.PosIsStmt {
  7833  		p.Pos = v.Pos.WithIsStmt()
  7834  	} else {
  7835  		p.Pos = v.Pos.WithNotStmt()
  7836  	}
  7837  	if sym, ok := v.Aux.(*ssa.AuxCall); ok && sym.Fn != nil {
  7838  		p.To.Type = obj.TYPE_MEM
  7839  		p.To.Name = obj.NAME_EXTERN
  7840  		p.To.Sym = sym.Fn
  7841  	} else {
  7842  		// TODO(mdempsky): Can these differences be eliminated?
  7843  		switch Arch.LinkArch.Family {
  7844  		case sys.AMD64, sys.I386, sys.PPC64, sys.RISCV64, sys.S390X, sys.Wasm:
  7845  			p.To.Type = obj.TYPE_REG
  7846  		case sys.ARM, sys.ARM64, sys.Loong64, sys.MIPS, sys.MIPS64:
  7847  			p.To.Type = obj.TYPE_MEM
  7848  		default:
  7849  			base.Fatalf("unknown indirect call family")
  7850  		}
  7851  		p.To.Reg = v.Args[0].Reg()
  7852  	}
  7853  	return p
  7854  }
  7855  
  7856  // TailCall returns a new tail call instruction for the SSA value v.
  7857  // It is like Call, but for a tail call.
  7858  func (s *State) TailCall(v *ssa.Value) *obj.Prog {
  7859  	p := s.Call(v)
  7860  	p.As = obj.ARET
  7861  	return p
  7862  }
  7863  
  7864  // PrepareCall prepares to emit a CALL instruction for v and does call-related bookkeeping.
  7865  // It must be called immediately before emitting the actual CALL instruction,
  7866  // since it emits PCDATA for the stack map at the call (calls are safe points).
  7867  func (s *State) PrepareCall(v *ssa.Value) {
  7868  	idx := s.livenessMap.Get(v)
  7869  	if !idx.StackMapValid() {
  7870  		// See Liveness.hasStackMap.
  7871  		if sym, ok := v.Aux.(*ssa.AuxCall); !ok || !(sym.Fn == ir.Syms.WBZero || sym.Fn == ir.Syms.WBMove) {
  7872  			base.Fatalf("missing stack map index for %v", v.LongString())
  7873  		}
  7874  	}
  7875  
  7876  	call, ok := v.Aux.(*ssa.AuxCall)
  7877  
  7878  	if ok {
  7879  		// Record call graph information for nowritebarrierrec
  7880  		// analysis.
  7881  		if nowritebarrierrecCheck != nil {
  7882  			nowritebarrierrecCheck.recordCall(s.pp.CurFunc, call.Fn, v.Pos)
  7883  		}
  7884  	}
  7885  
  7886  	if s.maxarg < v.AuxInt {
  7887  		s.maxarg = v.AuxInt
  7888  	}
  7889  }
  7890  
  7891  // UseArgs records the fact that an instruction needs a certain amount of
  7892  // callee args space for its use.
  7893  func (s *State) UseArgs(n int64) {
  7894  	if s.maxarg < n {
  7895  		s.maxarg = n
  7896  	}
  7897  }
  7898  
  7899  // fieldIdx finds the index of the field referred to by the ODOT node n.
  7900  func fieldIdx(n *ir.SelectorExpr) int {
  7901  	t := n.X.Type()
  7902  	if !isStructNotSIMD(t) {
  7903  		panic("ODOT's LHS is not a struct")
  7904  	}
  7905  
  7906  	for i, f := range t.Fields() {
  7907  		if f.Sym == n.Sel {
  7908  			if f.Offset != n.Offset() {
  7909  				panic("field offset doesn't match")
  7910  			}
  7911  			return i
  7912  		}
  7913  	}
  7914  	panic(fmt.Sprintf("can't find field in expr %v\n", n))
  7915  
  7916  	// TODO: keep the result of this function somewhere in the ODOT Node
  7917  	// so we don't have to recompute it each time we need it.
  7918  }
  7919  
  7920  // ssafn holds frontend information about a function that the backend is processing.
  7921  // It also exports a bunch of compiler services for the ssa backend.
  7922  type ssafn struct {
  7923  	curfn      *ir.Func
  7924  	strings    map[string]*obj.LSym // map from constant string to data symbols
  7925  	stksize    int64                // stack size for current frame
  7926  	stkptrsize int64                // prefix of stack containing pointers
  7927  
  7928  	// alignment for current frame.
  7929  	// NOTE: when stkalign > PtrSize, currently this only ensures the offsets of
  7930  	// objects in the stack frame are aligned. The stack pointer is still aligned
  7931  	// only PtrSize.
  7932  	stkalign int64
  7933  
  7934  	log bool // print ssa debug to the stdout
  7935  }
  7936  
  7937  // StringData returns a symbol which
  7938  // is the data component of a global string constant containing s.
  7939  func (e *ssafn) StringData(s string) *obj.LSym {
  7940  	if aux, ok := e.strings[s]; ok {
  7941  		return aux
  7942  	}
  7943  	if e.strings == nil {
  7944  		e.strings = make(map[string]*obj.LSym)
  7945  	}
  7946  	data := staticdata.StringSym(e.curfn.Pos(), s)
  7947  	e.strings[s] = data
  7948  	return data
  7949  }
  7950  
  7951  // SplitSlot returns a slot representing the data of parent starting at offset.
  7952  func (e *ssafn) SplitSlot(parent *ssa.LocalSlot, suffix string, offset int64, t *types.Type) ssa.LocalSlot {
  7953  	node := parent.N
  7954  
  7955  	if node.Class != ir.PAUTO || node.Addrtaken() {
  7956  		// addressed things and non-autos retain their parents (i.e., cannot truly be split)
  7957  		return ssa.LocalSlot{N: node, Type: t, Off: parent.Off + offset}
  7958  	}
  7959  
  7960  	sym := &types.Sym{Name: node.Sym().Name + suffix, Pkg: types.LocalPkg}
  7961  	n := e.curfn.NewLocal(parent.N.Pos(), sym, t)
  7962  	n.SetUsed(true)
  7963  	n.SetEsc(ir.EscNever)
  7964  	types.CalcSize(t)
  7965  	return ssa.LocalSlot{N: n, Type: t, Off: 0, SplitOf: parent, SplitOffset: offset}
  7966  }
  7967  
  7968  // Logf logs a message from the compiler.
  7969  func (e *ssafn) Logf(msg string, args ...any) {
  7970  	if e.log {
  7971  		fmt.Printf(msg, args...)
  7972  	}
  7973  }
  7974  
  7975  func (e *ssafn) Log() bool {
  7976  	return e.log
  7977  }
  7978  
  7979  // Fatalf reports a compiler error and exits.
  7980  func (e *ssafn) Fatalf(pos src.XPos, msg string, args ...any) {
  7981  	base.Pos = pos
  7982  	nargs := append([]any{ir.FuncName(e.curfn)}, args...)
  7983  	base.Fatalf("'%s': "+msg, nargs...)
  7984  }
  7985  
  7986  // Warnl reports a "warning", which is usually flag-triggered
  7987  // logging output for the benefit of tests.
  7988  func (e *ssafn) Warnl(pos src.XPos, fmt_ string, args ...any) {
  7989  	base.WarnfAt(pos, fmt_, args...)
  7990  }
  7991  
  7992  func (e *ssafn) Debug_checknil() bool {
  7993  	return base.Debug.Nil != 0
  7994  }
  7995  
  7996  func (e *ssafn) UseWriteBarrier() bool {
  7997  	return base.Flag.WB
  7998  }
  7999  
  8000  func (e *ssafn) Syslook(name string) *obj.LSym {
  8001  	switch name {
  8002  	case "goschedguarded":
  8003  		return ir.Syms.Goschedguarded
  8004  	case "writeBarrier":
  8005  		return ir.Syms.WriteBarrier
  8006  	case "wbZero":
  8007  		return ir.Syms.WBZero
  8008  	case "wbMove":
  8009  		return ir.Syms.WBMove
  8010  	case "cgoCheckMemmove":
  8011  		return ir.Syms.CgoCheckMemmove
  8012  	case "cgoCheckPtrWrite":
  8013  		return ir.Syms.CgoCheckPtrWrite
  8014  	}
  8015  	e.Fatalf(src.NoXPos, "unknown Syslook func %v", name)
  8016  	return nil
  8017  }
  8018  
  8019  func (e *ssafn) Func() *ir.Func {
  8020  	return e.curfn
  8021  }
  8022  
  8023  func clobberBase(n ir.Node) ir.Node {
  8024  	if n.Op() == ir.ODOT {
  8025  		n := n.(*ir.SelectorExpr)
  8026  		if n.X.Type().NumFields() == 1 {
  8027  			return clobberBase(n.X)
  8028  		}
  8029  	}
  8030  	if n.Op() == ir.OINDEX {
  8031  		n := n.(*ir.IndexExpr)
  8032  		if n.X.Type().IsArray() && n.X.Type().NumElem() == 1 {
  8033  			return clobberBase(n.X)
  8034  		}
  8035  	}
  8036  	return n
  8037  }
  8038  
  8039  // callTargetLSym returns the correct LSym to call 'callee' using its ABI.
  8040  func callTargetLSym(callee *ir.Name) *obj.LSym {
  8041  	if callee.Func == nil {
  8042  		// TODO(austin): This happens in case of interface method I.M from imported package.
  8043  		// It's ABIInternal, and would be better if callee.Func was never nil and we didn't
  8044  		// need this case.
  8045  		return callee.Linksym()
  8046  	}
  8047  
  8048  	return callee.LinksymABI(callee.Func.ABI)
  8049  }
  8050  
  8051  // deferStructFnField is the field index of _defer.fn.
  8052  const deferStructFnField = 4
  8053  
  8054  var deferType *types.Type
  8055  
  8056  // deferstruct returns a type interchangeable with runtime._defer.
  8057  // Make sure this stays in sync with runtime/runtime2.go:_defer.
  8058  func deferstruct() *types.Type {
  8059  	if deferType != nil {
  8060  		return deferType
  8061  	}
  8062  
  8063  	makefield := func(name string, t *types.Type) *types.Field {
  8064  		sym := (*types.Pkg)(nil).Lookup(name)
  8065  		return types.NewField(src.NoXPos, sym, t)
  8066  	}
  8067  
  8068  	fields := []*types.Field{
  8069  		makefield("heap", types.Types[types.TBOOL]),
  8070  		makefield("rangefunc", types.Types[types.TBOOL]),
  8071  		makefield("sp", types.Types[types.TUINTPTR]),
  8072  		makefield("pc", types.Types[types.TUINTPTR]),
  8073  		// Note: the types here don't really matter. Defer structures
  8074  		// are always scanned explicitly during stack copying and GC,
  8075  		// so we make them uintptr type even though they are real pointers.
  8076  		makefield("fn", types.Types[types.TUINTPTR]),
  8077  		makefield("link", types.Types[types.TUINTPTR]),
  8078  		makefield("head", types.Types[types.TUINTPTR]),
  8079  	}
  8080  	if name := fields[deferStructFnField].Sym.Name; name != "fn" {
  8081  		base.Fatalf("deferStructFnField is %q, not fn", name)
  8082  	}
  8083  
  8084  	n := ir.NewDeclNameAt(src.NoXPos, ir.OTYPE, ir.Pkgs.Runtime.Lookup("_defer"))
  8085  	typ := types.NewNamed(n)
  8086  	n.SetType(typ)
  8087  	n.SetTypecheck(1)
  8088  
  8089  	// build struct holding the above fields
  8090  	typ.SetUnderlying(types.NewStruct(fields))
  8091  	types.CalcStructSize(typ)
  8092  
  8093  	deferType = typ
  8094  	return typ
  8095  }
  8096  
  8097  // SpillSlotAddr uses LocalSlot information to initialize an obj.Addr
  8098  // The resulting addr is used in a non-standard context -- in the prologue
  8099  // of a function, before the frame has been constructed, so the standard
  8100  // addressing for the parameters will be wrong.
  8101  func SpillSlotAddr(spill ssa.Spill, baseReg int16, extraOffset int64) obj.Addr {
  8102  	return obj.Addr{
  8103  		Name:   obj.NAME_NONE,
  8104  		Type:   obj.TYPE_MEM,
  8105  		Reg:    baseReg,
  8106  		Offset: spill.Offset + extraOffset,
  8107  	}
  8108  }
  8109  
  8110  func isStructNotSIMD(t *types.Type) bool {
  8111  	return t.IsStruct() && !t.IsSIMD()
  8112  }
  8113  
  8114  var BoundsCheckFunc [ssa.BoundsKindCount]*obj.LSym
  8115