diff options
Diffstat (limited to 'src/cmd/compile/internal/base/flag.go')
| -rw-r--r-- | src/cmd/compile/internal/base/flag.go | 555 |
1 files changed, 555 insertions, 0 deletions
diff --git a/src/cmd/compile/internal/base/flag.go b/src/cmd/compile/internal/base/flag.go new file mode 100644 index 0000000..753a60a --- /dev/null +++ b/src/cmd/compile/internal/base/flag.go @@ -0,0 +1,555 @@ +// 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 base + +import ( + "encoding/json" + "flag" + "fmt" + "internal/buildcfg" + "internal/coverage" + "internal/platform" + "log" + "os" + "reflect" + "runtime" + "strings" + + "cmd/internal/obj" + "cmd/internal/objabi" + "cmd/internal/sys" +) + +func usage() { + fmt.Fprintf(os.Stderr, "usage: compile [options] file.go...\n") + objabi.Flagprint(os.Stderr) + Exit(2) +} + +// Flag holds the parsed command-line flags. +// See ParseFlag for non-zero defaults. +var Flag CmdFlags + +// A CountFlag is a counting integer flag. +// It accepts -name=value to set the value directly, +// but it also accepts -name with no =value to increment the count. +type CountFlag int + +// CmdFlags defines the command-line flags (see var Flag). +// Each struct field is a different flag, by default named for the lower-case of the field name. +// If the flag name is a single letter, the default flag name is left upper-case. +// If the flag name is "Lower" followed by a single letter, the default flag name is the lower-case of the last letter. +// +// If this default flag name can't be made right, the `flag` struct tag can be used to replace it, +// but this should be done only in exceptional circumstances: it helps everyone if the flag name +// is obvious from the field name when the flag is used elsewhere in the compiler sources. +// The `flag:"-"` struct tag makes a field invisible to the flag logic and should also be used sparingly. +// +// Each field must have a `help` struct tag giving the flag help message. +// +// The allowed field types are bool, int, string, pointers to those (for values stored elsewhere), +// CountFlag (for a counting flag), and func(string) (for a flag that uses special code for parsing). +type CmdFlags struct { + // Single letters + B CountFlag "help:\"disable bounds checking\"" + C CountFlag "help:\"disable printing of columns in error messages\"" + D string "help:\"set relative `path` for local imports\"" + E CountFlag "help:\"debug symbol export\"" + I func(string) "help:\"add `directory` to import search path\"" + K CountFlag "help:\"debug missing line numbers\"" + L CountFlag "help:\"also show actual source file names in error messages for positions affected by //line directives\"" + N CountFlag "help:\"disable optimizations\"" + S CountFlag "help:\"print assembly listing\"" + // V is added by objabi.AddVersionFlag + W CountFlag "help:\"debug parse tree after type checking\"" + + LowerC int "help:\"concurrency during compilation (1 means no concurrency)\"" + LowerD flag.Value "help:\"enable debugging settings; try -d help\"" + LowerE CountFlag "help:\"no limit on number of errors reported\"" + LowerH CountFlag "help:\"halt on error\"" + LowerJ CountFlag "help:\"debug runtime-initialized variables\"" + LowerL CountFlag "help:\"disable inlining\"" + LowerM CountFlag "help:\"print optimization decisions\"" + LowerO string "help:\"write output to `file`\"" + LowerP *string "help:\"set expected package import `path`\"" // &Ctxt.Pkgpath, set below + LowerR CountFlag "help:\"debug generated wrappers\"" + LowerT bool "help:\"enable tracing for debugging the compiler\"" + LowerW CountFlag "help:\"debug type checking\"" + LowerV *bool "help:\"increase debug verbosity\"" + + // Special characters + Percent CountFlag "flag:\"%\" help:\"debug non-static initializers\"" + CompilingRuntime bool "flag:\"+\" help:\"compiling runtime\"" + + // Longer names + AsmHdr string "help:\"write assembly header to `file`\"" + ASan bool "help:\"build code compatible with C/C++ address sanitizer\"" + Bench string "help:\"append benchmark times to `file`\"" + BlockProfile string "help:\"write block profile to `file`\"" + BuildID string "help:\"record `id` as the build id in the export metadata\"" + CPUProfile string "help:\"write cpu profile to `file`\"" + Complete bool "help:\"compiling complete package (no C or assembly)\"" + ClobberDead bool "help:\"clobber dead stack slots (for debugging)\"" + ClobberDeadReg bool "help:\"clobber dead registers (for debugging)\"" + Dwarf bool "help:\"generate DWARF symbols\"" + DwarfBASEntries *bool "help:\"use base address selection entries in DWARF\"" // &Ctxt.UseBASEntries, set below + DwarfLocationLists *bool "help:\"add location lists to DWARF in optimized mode\"" // &Ctxt.Flag_locationlists, set below + Dynlink *bool "help:\"support references to Go symbols defined in other shared libraries\"" // &Ctxt.Flag_dynlink, set below + EmbedCfg func(string) "help:\"read go:embed configuration from `file`\"" + GenDwarfInl int "help:\"generate DWARF inline info records\"" // 0=disabled, 1=funcs, 2=funcs+formals/locals + GoVersion string "help:\"required version of the runtime\"" + ImportCfg func(string) "help:\"read import configuration from `file`\"" + InstallSuffix string "help:\"set pkg directory `suffix`\"" + JSON string "help:\"version,file for JSON compiler/optimizer detail output\"" + Lang string "help:\"Go language version source code expects\"" + LinkObj string "help:\"write linker-specific object to `file`\"" + LinkShared *bool "help:\"generate code that will be linked against Go shared libraries\"" // &Ctxt.Flag_linkshared, set below + Live CountFlag "help:\"debug liveness analysis\"" + MSan bool "help:\"build code compatible with C/C++ memory sanitizer\"" + MemProfile string "help:\"write memory profile to `file`\"" + MemProfileRate int "help:\"set runtime.MemProfileRate to `rate`\"" + MutexProfile string "help:\"write mutex profile to `file`\"" + NoLocalImports bool "help:\"reject local (relative) imports\"" + CoverageCfg func(string) "help:\"read coverage configuration from `file`\"" + Pack bool "help:\"write to file.a instead of file.o\"" + Race bool "help:\"enable race detector\"" + Shared *bool "help:\"generate code that can be linked into a shared library\"" // &Ctxt.Flag_shared, set below + SmallFrames bool "help:\"reduce the size limit for stack allocated objects\"" // small stacks, to diagnose GC latency; see golang.org/issue/27732 + Spectre string "help:\"enable spectre mitigations in `list` (all, index, ret)\"" + Std bool "help:\"compiling standard library\"" + SymABIs string "help:\"read symbol ABIs from `file`\"" + TraceProfile string "help:\"write an execution trace to `file`\"" + TrimPath string "help:\"remove `prefix` from recorded source file paths\"" + WB bool "help:\"enable write barrier\"" // TODO: remove + PgoProfile string "help:\"read profile from `file`\"" + ErrorURL bool "help:\"print explanatory URL with error message if applicable\"" + + // Configuration derived from flags; not a flag itself. + Cfg struct { + Embed struct { // set by -embedcfg + Patterns map[string][]string + Files map[string]string + } + ImportDirs []string // appended to by -I + ImportMap map[string]string // set by -importcfg + PackageFile map[string]string // set by -importcfg; nil means not in use + CoverageInfo *coverage.CoverFixupConfig // set by -coveragecfg + SpectreIndex bool // set by -spectre=index or -spectre=all + // Whether we are adding any sort of code instrumentation, such as + // when the race detector is enabled. + Instrumenting bool + } +} + +// ParseFlags parses the command-line flags into Flag. +func ParseFlags() { + Flag.I = addImportDir + + Flag.LowerC = runtime.GOMAXPROCS(0) + Flag.LowerD = objabi.NewDebugFlag(&Debug, DebugSSA) + Flag.LowerP = &Ctxt.Pkgpath + Flag.LowerV = &Ctxt.Debugvlog + + Flag.Dwarf = buildcfg.GOARCH != "wasm" + Flag.DwarfBASEntries = &Ctxt.UseBASEntries + Flag.DwarfLocationLists = &Ctxt.Flag_locationlists + *Flag.DwarfLocationLists = true + Flag.Dynlink = &Ctxt.Flag_dynlink + Flag.EmbedCfg = readEmbedCfg + Flag.GenDwarfInl = 2 + Flag.ImportCfg = readImportCfg + Flag.CoverageCfg = readCoverageCfg + Flag.LinkShared = &Ctxt.Flag_linkshared + Flag.Shared = &Ctxt.Flag_shared + Flag.WB = true + + Debug.ConcurrentOk = true + Debug.InlFuncsWithClosures = 1 + Debug.InlStaticInit = 1 + Debug.PGOInline = 1 + Debug.PGODevirtualize = 1 + Debug.SyncFrames = -1 // disable sync markers by default + + Debug.Checkptr = -1 // so we can tell whether it is set explicitly + + Flag.Cfg.ImportMap = make(map[string]string) + + objabi.AddVersionFlag() // -V + registerFlags() + objabi.Flagparse(usage) + + if gcd := os.Getenv("GOCOMPILEDEBUG"); gcd != "" { + // This will only override the flags set in gcd; + // any others set on the command line remain set. + Flag.LowerD.Set(gcd) + } + + if Debug.Gossahash != "" { + hashDebug = NewHashDebug("gossahash", Debug.Gossahash, nil) + } + + // Three inputs govern loop iteration variable rewriting, hash, experiment, flag. + // The loop variable rewriting is: + // IF non-empty hash, then hash determines behavior (function+line match) (*) + // ELSE IF experiment and flag==0, then experiment (set flag=1) + // ELSE flag (note that build sets flag per-package), with behaviors: + // -1 => no change to behavior. + // 0 => no change to behavior (unless non-empty hash, see above) + // 1 => apply change to likely-iteration-variable-escaping loops + // 2 => apply change, log results + // 11 => apply change EVERYWHERE, do not log results (for debugging/benchmarking) + // 12 => apply change EVERYWHERE, log results (for debugging/benchmarking) + // + // The expected uses of the these inputs are, in believed most-likely to least likely: + // GOEXPERIMENT=loopvar -- apply change to entire application + // -gcflags=some_package=-d=loopvar=1 -- apply change to some_package (**) + // -gcflags=some_package=-d=loopvar=2 -- apply change to some_package, log it + // GOEXPERIMENT=loopvar -gcflags=some_package=-d=loopvar=-1 -- apply change to all but one package + // GOCOMPILEDEBUG=loopvarhash=... -- search for failure cause + // + // (*) For debugging purposes, providing loopvar flag >= 11 will expand the hash-eligible set of loops to all. + // (**) Loop semantics, changed or not, follow code from a package when it is inlined; that is, the behavior + // of an application compiled with partially modified loop semantics does not depend on inlining. + + if Debug.LoopVarHash != "" { + // This first little bit controls the inputs for debug-hash-matching. + mostInlineOnly := true + if strings.HasPrefix(Debug.LoopVarHash, "IL") { + // When hash-searching on a position that is an inline site, default is to use the + // most-inlined position only. This makes the hash faster, plus there's no point + // reporting a problem with all the inlining; there's only one copy of the source. + // However, if for some reason you wanted it per-site, you can get this. (The default + // hash-search behavior for compiler debugging is at an inline site.) + Debug.LoopVarHash = Debug.LoopVarHash[2:] + mostInlineOnly = false + } + // end of testing trickiness + LoopVarHash = NewHashDebug("loopvarhash", Debug.LoopVarHash, nil) + if Debug.LoopVar < 11 { // >= 11 means all loops are rewrite-eligible + Debug.LoopVar = 1 // 1 means those loops that syntactically escape their dcl vars are eligible. + } + LoopVarHash.SetInlineSuffixOnly(mostInlineOnly) + } else if buildcfg.Experiment.LoopVar && Debug.LoopVar == 0 { + Debug.LoopVar = 1 + } + + if Debug.Fmahash != "" { + FmaHash = NewHashDebug("fmahash", Debug.Fmahash, nil) + } + + if Flag.MSan && !platform.MSanSupported(buildcfg.GOOS, buildcfg.GOARCH) { + log.Fatalf("%s/%s does not support -msan", buildcfg.GOOS, buildcfg.GOARCH) + } + if Flag.ASan && !platform.ASanSupported(buildcfg.GOOS, buildcfg.GOARCH) { + log.Fatalf("%s/%s does not support -asan", buildcfg.GOOS, buildcfg.GOARCH) + } + if Flag.Race && !platform.RaceDetectorSupported(buildcfg.GOOS, buildcfg.GOARCH) { + log.Fatalf("%s/%s does not support -race", buildcfg.GOOS, buildcfg.GOARCH) + } + if (*Flag.Shared || *Flag.Dynlink || *Flag.LinkShared) && !Ctxt.Arch.InFamily(sys.AMD64, sys.ARM, sys.ARM64, sys.I386, sys.Loong64, sys.MIPS64, sys.PPC64, sys.RISCV64, sys.S390X) { + log.Fatalf("%s/%s does not support -shared", buildcfg.GOOS, buildcfg.GOARCH) + } + parseSpectre(Flag.Spectre) // left as string for RecordFlags + + Ctxt.Flag_shared = Ctxt.Flag_dynlink || Ctxt.Flag_shared + Ctxt.Flag_optimize = Flag.N == 0 + Ctxt.Debugasm = int(Flag.S) + Ctxt.Flag_maymorestack = Debug.MayMoreStack + Ctxt.Flag_noRefName = Debug.NoRefName != 0 + + if flag.NArg() < 1 { + usage() + } + + if Flag.GoVersion != "" && Flag.GoVersion != runtime.Version() { + fmt.Printf("compile: version %q does not match go tool version %q\n", runtime.Version(), Flag.GoVersion) + Exit(2) + } + + if *Flag.LowerP == "" { + *Flag.LowerP = obj.UnlinkablePkg + } + + if Flag.LowerO == "" { + p := flag.Arg(0) + if i := strings.LastIndex(p, "/"); i >= 0 { + p = p[i+1:] + } + if runtime.GOOS == "windows" { + if i := strings.LastIndex(p, `\`); i >= 0 { + p = p[i+1:] + } + } + if i := strings.LastIndex(p, "."); i >= 0 { + p = p[:i] + } + suffix := ".o" + if Flag.Pack { + suffix = ".a" + } + Flag.LowerO = p + suffix + } + switch { + case Flag.Race && Flag.MSan: + log.Fatal("cannot use both -race and -msan") + case Flag.Race && Flag.ASan: + log.Fatal("cannot use both -race and -asan") + case Flag.MSan && Flag.ASan: + log.Fatal("cannot use both -msan and -asan") + } + if Flag.Race || Flag.MSan || Flag.ASan { + // -race, -msan and -asan imply -d=checkptr for now. + if Debug.Checkptr == -1 { // if not set explicitly + Debug.Checkptr = 1 + } + } + + if Flag.CompilingRuntime && Flag.N != 0 { + log.Fatal("cannot disable optimizations while compiling runtime") + } + if Flag.LowerC < 1 { + log.Fatalf("-c must be at least 1, got %d", Flag.LowerC) + } + if !concurrentBackendAllowed() { + Flag.LowerC = 1 + } + + if Flag.CompilingRuntime { + // Runtime can't use -d=checkptr, at least not yet. + Debug.Checkptr = 0 + + // Fuzzing the runtime isn't interesting either. + Debug.Libfuzzer = 0 + } + + if Debug.Checkptr == -1 { // if not set explicitly + Debug.Checkptr = 0 + } + + // set via a -d flag + Ctxt.Debugpcln = Debug.PCTab +} + +// registerFlags adds flag registrations for all the fields in Flag. +// See the comment on type CmdFlags for the rules. +func registerFlags() { + var ( + boolType = reflect.TypeOf(bool(false)) + intType = reflect.TypeOf(int(0)) + stringType = reflect.TypeOf(string("")) + ptrBoolType = reflect.TypeOf(new(bool)) + ptrIntType = reflect.TypeOf(new(int)) + ptrStringType = reflect.TypeOf(new(string)) + countType = reflect.TypeOf(CountFlag(0)) + funcType = reflect.TypeOf((func(string))(nil)) + ) + + v := reflect.ValueOf(&Flag).Elem() + t := v.Type() + for i := 0; i < t.NumField(); i++ { + f := t.Field(i) + if f.Name == "Cfg" { + continue + } + + var name string + if len(f.Name) == 1 { + name = f.Name + } else if len(f.Name) == 6 && f.Name[:5] == "Lower" && 'A' <= f.Name[5] && f.Name[5] <= 'Z' { + name = string(rune(f.Name[5] + 'a' - 'A')) + } else { + name = strings.ToLower(f.Name) + } + if tag := f.Tag.Get("flag"); tag != "" { + name = tag + } + + help := f.Tag.Get("help") + if help == "" { + panic(fmt.Sprintf("base.Flag.%s is missing help text", f.Name)) + } + + if k := f.Type.Kind(); (k == reflect.Ptr || k == reflect.Func) && v.Field(i).IsNil() { + panic(fmt.Sprintf("base.Flag.%s is uninitialized %v", f.Name, f.Type)) + } + + switch f.Type { + case boolType: + p := v.Field(i).Addr().Interface().(*bool) + flag.BoolVar(p, name, *p, help) + case intType: + p := v.Field(i).Addr().Interface().(*int) + flag.IntVar(p, name, *p, help) + case stringType: + p := v.Field(i).Addr().Interface().(*string) + flag.StringVar(p, name, *p, help) + case ptrBoolType: + p := v.Field(i).Interface().(*bool) + flag.BoolVar(p, name, *p, help) + case ptrIntType: + p := v.Field(i).Interface().(*int) + flag.IntVar(p, name, *p, help) + case ptrStringType: + p := v.Field(i).Interface().(*string) + flag.StringVar(p, name, *p, help) + case countType: + p := (*int)(v.Field(i).Addr().Interface().(*CountFlag)) + objabi.Flagcount(name, help, p) + case funcType: + f := v.Field(i).Interface().(func(string)) + objabi.Flagfn1(name, help, f) + default: + if val, ok := v.Field(i).Interface().(flag.Value); ok { + flag.Var(val, name, help) + } else { + panic(fmt.Sprintf("base.Flag.%s has unexpected type %s", f.Name, f.Type)) + } + } + } +} + +// concurrentFlagOk reports whether the current compiler flags +// are compatible with concurrent compilation. +func concurrentFlagOk() bool { + // TODO(rsc): Many of these are fine. Remove them. + return Flag.Percent == 0 && + Flag.E == 0 && + Flag.K == 0 && + Flag.L == 0 && + Flag.LowerH == 0 && + Flag.LowerJ == 0 && + Flag.LowerM == 0 && + Flag.LowerR == 0 +} + +func concurrentBackendAllowed() bool { + if !concurrentFlagOk() { + return false + } + + // Debug.S by itself is ok, because all printing occurs + // while writing the object file, and that is non-concurrent. + // Adding Debug_vlog, however, causes Debug.S to also print + // while flushing the plist, which happens concurrently. + if Ctxt.Debugvlog || !Debug.ConcurrentOk || Flag.Live > 0 { + return false + } + // TODO: Test and delete this condition. + if buildcfg.Experiment.FieldTrack { + return false + } + // TODO: fix races and enable the following flags + if Ctxt.Flag_dynlink || Flag.Race { + return false + } + return true +} + +func addImportDir(dir string) { + if dir != "" { + Flag.Cfg.ImportDirs = append(Flag.Cfg.ImportDirs, dir) + } +} + +func readImportCfg(file string) { + if Flag.Cfg.ImportMap == nil { + Flag.Cfg.ImportMap = make(map[string]string) + } + Flag.Cfg.PackageFile = map[string]string{} + data, err := os.ReadFile(file) + if err != nil { + log.Fatalf("-importcfg: %v", err) + } + + for lineNum, line := range strings.Split(string(data), "\n") { + lineNum++ // 1-based + line = strings.TrimSpace(line) + if line == "" || strings.HasPrefix(line, "#") { + continue + } + + var verb, args string + if i := strings.Index(line, " "); i < 0 { + verb = line + } else { + verb, args = line[:i], strings.TrimSpace(line[i+1:]) + } + var before, after string + if i := strings.Index(args, "="); i >= 0 { + before, after = args[:i], args[i+1:] + } + switch verb { + default: + log.Fatalf("%s:%d: unknown directive %q", file, lineNum, verb) + case "importmap": + if before == "" || after == "" { + log.Fatalf(`%s:%d: invalid importmap: syntax is "importmap old=new"`, file, lineNum) + } + Flag.Cfg.ImportMap[before] = after + case "packagefile": + if before == "" || after == "" { + log.Fatalf(`%s:%d: invalid packagefile: syntax is "packagefile path=filename"`, file, lineNum) + } + Flag.Cfg.PackageFile[before] = after + } + } +} + +func readCoverageCfg(file string) { + var cfg coverage.CoverFixupConfig + data, err := os.ReadFile(file) + if err != nil { + log.Fatalf("-coveragecfg: %v", err) + } + if err := json.Unmarshal(data, &cfg); err != nil { + log.Fatalf("error reading -coveragecfg file %q: %v", file, err) + } + Flag.Cfg.CoverageInfo = &cfg +} + +func readEmbedCfg(file string) { + data, err := os.ReadFile(file) + if err != nil { + log.Fatalf("-embedcfg: %v", err) + } + if err := json.Unmarshal(data, &Flag.Cfg.Embed); err != nil { + log.Fatalf("%s: %v", file, err) + } + if Flag.Cfg.Embed.Patterns == nil { + log.Fatalf("%s: invalid embedcfg: missing Patterns", file) + } + if Flag.Cfg.Embed.Files == nil { + log.Fatalf("%s: invalid embedcfg: missing Files", file) + } +} + +// parseSpectre parses the spectre configuration from the string s. +func parseSpectre(s string) { + for _, f := range strings.Split(s, ",") { + f = strings.TrimSpace(f) + switch f { + default: + log.Fatalf("unknown setting -spectre=%s", f) + case "": + // nothing + case "all": + Flag.Cfg.SpectreIndex = true + Ctxt.Retpoline = true + case "index": + Flag.Cfg.SpectreIndex = true + case "ret": + Ctxt.Retpoline = true + } + } + + if Flag.Cfg.SpectreIndex { + switch buildcfg.GOARCH { + case "amd64": + // ok + default: + log.Fatalf("GOARCH=%s does not support -spectre=index", buildcfg.GOARCH) + } + } +} |