1 files changed, 402 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
new file mode 100644
index 0000000..4a37548
--- /dev/null
+++ b/src/cmd/compile/internal/gc/main.go
@@ -0,0 +1,402 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package gc
+
+import (
+	"bufio"
+	"bytes"
+	"cmd/compile/internal/base"
+	"cmd/compile/internal/coverage"
+	"cmd/compile/internal/deadcode"
+	"cmd/compile/internal/devirtualize"
+	"cmd/compile/internal/dwarfgen"
+	"cmd/compile/internal/escape"
+	"cmd/compile/internal/inline"
+	"cmd/compile/internal/ir"
+	"cmd/compile/internal/logopt"
+	"cmd/compile/internal/noder"
+	"cmd/compile/internal/pgo"
+	"cmd/compile/internal/pkginit"
+	"cmd/compile/internal/reflectdata"
+	"cmd/compile/internal/ssa"
+	"cmd/compile/internal/ssagen"
+	"cmd/compile/internal/typecheck"
+	"cmd/compile/internal/types"
+	"cmd/internal/dwarf"
+	"cmd/internal/obj"
+	"cmd/internal/objabi"
+	"cmd/internal/src"
+	"flag"
+	"fmt"
+	"internal/buildcfg"
+	"log"
+	"os"
+	"runtime"
+)
+
+// handlePanic ensures that we print out an "internal compiler error" for any panic
+// or runtime exception during front-end compiler processing (unless there have
+// already been some compiler errors). It may also be invoked from the explicit panic in
+// hcrash(), in which case, we pass the panic on through.
+func handlePanic() {
+	if err := recover(); err != nil {
+		if err == "-h" {
+			// Force real panic now with -h option (hcrash) - the error
+			// information will have already been printed.
+			panic(err)
+		}
+		base.Fatalf("panic: %v", err)
+	}
+}
+
+// Main parses flags and Go source files specified in the command-line
+// arguments, type-checks the parsed Go package, compiles functions to machine
+// code, and finally writes the compiled package definition to disk.
+func Main(archInit func(*ssagen.ArchInfo)) {
+	base.Timer.Start("fe", "init")
+
+	defer handlePanic()
+
+	archInit(&ssagen.Arch)
+
+	base.Ctxt = obj.Linknew(ssagen.Arch.LinkArch)
+	base.Ctxt.DiagFunc = base.Errorf
+	base.Ctxt.DiagFlush = base.FlushErrors
+	base.Ctxt.Bso = bufio.NewWriter(os.Stdout)
+
+	// UseBASEntries is preferred because it shaves about 2% off build time, but LLDB, dsymutil, and dwarfdump
+	// on Darwin don't support it properly, especially since macOS 10.14 (Mojave).  This is exposed as a flag
+	// to allow testing with LLVM tools on Linux, and to help with reporting this bug to the LLVM project.
+	// See bugs 31188 and 21945 (CLs 170638, 98075, 72371).
+	base.Ctxt.UseBASEntries = base.Ctxt.Headtype != objabi.Hdarwin
+
+	base.DebugSSA = ssa.PhaseOption
+	base.ParseFlags()
+
+	if os.Getenv("GOGC") == "" { // GOGC set disables starting heap adjustment
+		// More processors will use more heap, but assume that more memory is available.
+		// So 1 processor -> 40MB, 4 -> 64MB, 12 -> 128MB
+		base.AdjustStartingHeap(uint64(32+8*base.Flag.LowerC) << 20)
+	}
+
+	types.LocalPkg = types.NewPkg(base.Ctxt.Pkgpath, "")
+
+	// pseudo-package, for scoping
+	types.BuiltinPkg = types.NewPkg("go.builtin", "") // TODO(gri) name this package go.builtin?
+	types.BuiltinPkg.Prefix = "go:builtin"
+
+	// pseudo-package, accessed by import "unsafe"
+	types.UnsafePkg = types.NewPkg("unsafe", "unsafe")
+
+	// Pseudo-package that contains the compiler's builtin
+	// declarations for package runtime. These are declared in a
+	// separate package to avoid conflicts with package runtime's
+	// actual declarations, which may differ intentionally but
+	// insignificantly.
+	ir.Pkgs.Runtime = types.NewPkg("go.runtime", "runtime")
+	ir.Pkgs.Runtime.Prefix = "runtime"
+
+	// pseudo-packages used in symbol tables
+	ir.Pkgs.Itab = types.NewPkg("go.itab", "go.itab")
+	ir.Pkgs.Itab.Prefix = "go:itab"
+
+	// pseudo-package used for methods with anonymous receivers
+	ir.Pkgs.Go = types.NewPkg("go", "")
+
+	// pseudo-package for use with code coverage instrumentation.
+	ir.Pkgs.Coverage = types.NewPkg("go.coverage", "runtime/coverage")
+	ir.Pkgs.Coverage.Prefix = "runtime/coverage"
+
+	// Record flags that affect the build result. (And don't
+	// record flags that don't, since that would cause spurious
+	// changes in the binary.)
+	dwarfgen.RecordFlags("B", "N", "l", "msan", "race", "asan", "shared", "dynlink", "dwarf", "dwarflocationlists", "dwarfbasentries", "smallframes", "spectre")
+
+	if !base.EnableTrace && base.Flag.LowerT {
+		log.Fatalf("compiler not built with support for -t")
+	}
+
+	// Enable inlining (after RecordFlags, to avoid recording the rewritten -l).  For now:
+	//	default: inlining on.  (Flag.LowerL == 1)
+	//	-l: inlining off  (Flag.LowerL == 0)
+	//	-l=2, -l=3: inlining on again, with extra debugging (Flag.LowerL > 1)
+	if base.Flag.LowerL <= 1 {
+		base.Flag.LowerL = 1 - base.Flag.LowerL
+	}
+
+	if base.Flag.SmallFrames {
+		ir.MaxStackVarSize = 128 * 1024
+		ir.MaxImplicitStackVarSize = 16 * 1024
+	}
+
+	if base.Flag.Dwarf {
+		base.Ctxt.DebugInfo = dwarfgen.Info
+		base.Ctxt.GenAbstractFunc = dwarfgen.AbstractFunc
+		base.Ctxt.DwFixups = obj.NewDwarfFixupTable(base.Ctxt)
+	} else {
+		// turn off inline generation if no dwarf at all
+		base.Flag.GenDwarfInl = 0
+		base.Ctxt.Flag_locationlists = false
+	}
+	if base.Ctxt.Flag_locationlists && len(base.Ctxt.Arch.DWARFRegisters) == 0 {
+		log.Fatalf("location lists requested but register mapping not available on %v", base.Ctxt.Arch.Name)
+	}
+
+	types.ParseLangFlag()
+
+	symABIs := ssagen.NewSymABIs()
+	if base.Flag.SymABIs != "" {
+		symABIs.ReadSymABIs(base.Flag.SymABIs)
+	}
+
+	if base.Compiling(base.NoInstrumentPkgs) {
+		base.Flag.Race = false
+		base.Flag.MSan = false
+		base.Flag.ASan = false
+	}
+
+	ssagen.Arch.LinkArch.Init(base.Ctxt)
+	startProfile()
+	if base.Flag.Race || base.Flag.MSan || base.Flag.ASan {
+		base.Flag.Cfg.Instrumenting = true
+	}
+	if base.Flag.Dwarf {
+		dwarf.EnableLogging(base.Debug.DwarfInl != 0)
+	}
+	if base.Debug.SoftFloat != 0 {
+		ssagen.Arch.SoftFloat = true
+	}
+
+	if base.Flag.JSON != "" { // parse version,destination from json logging optimization.
+		logopt.LogJsonOption(base.Flag.JSON)
+	}
+
+	ir.EscFmt = escape.Fmt
+	ir.IsIntrinsicCall = ssagen.IsIntrinsicCall
+	inline.SSADumpInline = ssagen.DumpInline
+	ssagen.InitEnv()
+	ssagen.InitTables()
+
+	types.PtrSize = ssagen.Arch.LinkArch.PtrSize
+	types.RegSize = ssagen.Arch.LinkArch.RegSize
+	types.MaxWidth = ssagen.Arch.MAXWIDTH
+
+	typecheck.Target = new(ir.Package)
+
+	typecheck.NeedRuntimeType = reflectdata.NeedRuntimeType // TODO(rsc): TypeSym for lock?
+
+	base.AutogeneratedPos = makePos(src.NewFileBase("<autogenerated>", "<autogenerated>"), 1, 0)
+
+	typecheck.InitUniverse()
+	typecheck.InitRuntime()
+
+	// Parse and typecheck input.
+	noder.LoadPackage(flag.Args())
+
+	// As a convenience to users (toolchain maintainers, in particular),
+	// when compiling a package named "main", we default the package
+	// path to "main" if the -p flag was not specified.
+	if base.Ctxt.Pkgpath == obj.UnlinkablePkg && types.LocalPkg.Name == "main" {
+		base.Ctxt.Pkgpath = "main"
+		types.LocalPkg.Path = "main"
+		types.LocalPkg.Prefix = "main"
+	}
+
+	dwarfgen.RecordPackageName()
+
+	// Prepare for backend processing. This must happen before pkginit,
+	// because it generates itabs for initializing global variables.
+	ssagen.InitConfig()
+
+	// First part of coverage fixup (if applicable).
+	var cnames coverage.Names
+	if base.Flag.Cfg.CoverageInfo != nil {
+		cnames = coverage.FixupVars()
+	}
+
+	// Create "init" function for package-scope variable initialization
+	// statements, if any.
+	//
+	// Note: This needs to happen early, before any optimizations. The
+	// Go spec defines a precise order than initialization should be
+	// carried out in, and even mundane optimizations like dead code
+	// removal can skew the results (e.g., #43444).
+	pkginit.MakeInit()
+
+	// Second part of code coverage fixup (init func modification),
+	// if applicable.
+	if base.Flag.Cfg.CoverageInfo != nil {
+		coverage.FixupInit(cnames)
+	}
+
+	// Eliminate some obviously dead code.
+	// Must happen after typechecking.
+	for _, n := range typecheck.Target.Decls {
+		if n.Op() == ir.ODCLFUNC {
+			deadcode.Func(n.(*ir.Func))
+		}
+	}
+
+	// Compute Addrtaken for names.
+	// We need to wait until typechecking is done so that when we see &x[i]
+	// we know that x has its address taken if x is an array, but not if x is a slice.
+	// We compute Addrtaken in bulk here.
+	// After this phase, we maintain Addrtaken incrementally.
+	if typecheck.DirtyAddrtaken {
+		typecheck.ComputeAddrtaken(typecheck.Target.Decls)
+		typecheck.DirtyAddrtaken = false
+	}
+	typecheck.IncrementalAddrtaken = true
+
+	if base.Debug.TypecheckInl != 0 {
+		// Typecheck imported function bodies if Debug.l > 1,
+		// otherwise lazily when used or re-exported.
+		typecheck.AllImportedBodies()
+	}
+
+	// Read profile file and build profile-graph and weighted-call-graph.
+	base.Timer.Start("fe", "pgoprofile")
+	var profile *pgo.Profile
+	if base.Flag.PgoProfile != "" {
+		profile = pgo.New(base.Flag.PgoProfile)
+	}
+
+	// Inlining
+	base.Timer.Start("fe", "inlining")
+	if base.Flag.LowerL != 0 {
+		inline.InlinePackage(profile)
+	}
+	noder.MakeWrappers(typecheck.Target) // must happen after inlining
+
+	// Devirtualize.
+	for _, n := range typecheck.Target.Decls {
+		if n.Op() == ir.ODCLFUNC {
+			devirtualize.Func(n.(*ir.Func))
+		}
+	}
+	ir.CurFunc = nil
+
+	// Build init task, if needed.
+	if initTask := pkginit.Task(); initTask != nil {
+		typecheck.Export(initTask)
+	}
+
+	// Generate ABI wrappers. Must happen before escape analysis
+	// and doesn't benefit from dead-coding or inlining.
+	symABIs.GenABIWrappers()
+
+	// Escape analysis.
+	// Required for moving heap allocations onto stack,
+	// which in turn is required by the closure implementation,
+	// which stores the addresses of stack variables into the closure.
+	// If the closure does not escape, it needs to be on the stack
+	// or else the stack copier will not update it.
+	// Large values are also moved off stack in escape analysis;
+	// because large values may contain pointers, it must happen early.
+	base.Timer.Start("fe", "escapes")
+	escape.Funcs(typecheck.Target.Decls)
+
+	// TODO(mdempsky): This is a hack. We need a proper, global work
+	// queue for scheduling function compilation so components don't
+	// need to adjust their behavior depending on when they're called.
+	reflectdata.AfterGlobalEscapeAnalysis = true
+
+	// Collect information for go:nowritebarrierrec
+	// checking. This must happen before transforming closures during Walk
+	// We'll do the final check after write barriers are
+	// inserted.
+	if base.Flag.CompilingRuntime {
+		ssagen.EnableNoWriteBarrierRecCheck()
+	}
+
+	ir.CurFunc = nil
+
+	// Compile top level functions.
+	// Don't use range--walk can add functions to Target.Decls.
+	base.Timer.Start("be", "compilefuncs")
+	fcount := int64(0)
+	for i := 0; i < len(typecheck.Target.Decls); i++ {
+		if fn, ok := typecheck.Target.Decls[i].(*ir.Func); ok {
+			// Don't try compiling dead hidden closure.
+			if fn.IsDeadcodeClosure() {
+				continue
+			}
+			enqueueFunc(fn)
+			fcount++
+		}
+	}
+	base.Timer.AddEvent(fcount, "funcs")
+
+	compileFunctions()
+
+	if base.Flag.CompilingRuntime {
+		// Write barriers are now known. Check the call graph.
+		ssagen.NoWriteBarrierRecCheck()
+	}
+
+	// Finalize DWARF inline routine DIEs, then explicitly turn off
+	// DWARF inlining gen so as to avoid problems with generated
+	// method wrappers.
+	if base.Ctxt.DwFixups != nil {
+		base.Ctxt.DwFixups.Finalize(base.Ctxt.Pkgpath, base.Debug.DwarfInl != 0)
+		base.Ctxt.DwFixups = nil
+		base.Flag.GenDwarfInl = 0
+	}
+
+	// Write object data to disk.
+	base.Timer.Start("be", "dumpobj")
+	dumpdata()
+	base.Ctxt.NumberSyms()
+	dumpobj()
+	if base.Flag.AsmHdr != "" {
+		dumpasmhdr()
+	}
+
+	ssagen.CheckLargeStacks()
+	typecheck.CheckFuncStack()
+
+	if len(compilequeue) != 0 {
+		base.Fatalf("%d uncompiled functions", len(compilequeue))
+	}
+
+	logopt.FlushLoggedOpts(base.Ctxt, base.Ctxt.Pkgpath)
+	base.ExitIfErrors()
+
+	base.FlushErrors()
+	base.Timer.Stop()
+
+	if base.Flag.Bench != "" {
+		if err := writebench(base.Flag.Bench); err != nil {
+			log.Fatalf("cannot write benchmark data: %v", err)
+		}
+	}
+}
+
+func writebench(filename string) error {
+	f, err := os.OpenFile(filename, os.O_WRONLY|os.O_CREATE|os.O_APPEND, 0666)
+	if err != nil {
+		return err
+	}
+
+	var buf bytes.Buffer
+	fmt.Fprintln(&buf, "commit:", buildcfg.Version)
+	fmt.Fprintln(&buf, "goos:", runtime.GOOS)
+	fmt.Fprintln(&buf, "goarch:", runtime.GOARCH)
+	base.Timer.Write(&buf, "BenchmarkCompile:"+base.Ctxt.Pkgpath+":")
+
+	n, err := f.Write(buf.Bytes())
+	if err != nil {
+		return err
+	}
+	if n != buf.Len() {
+		panic("bad writer")
+	}
+
+	return f.Close()
+}
+
+func makePos(b *src.PosBase, line, col uint) src.XPos {
+	return base.Ctxt.PosTable.XPos(src.MakePos(b, line, col))
+}