internal/buildcfg: move build configuration out of cmd/internal/objabi

The go/build package needs access to this configuration,
so move it into a new package available to the standard library.

Change-Id: I868a94148b52350c76116451f4ad9191246adcff
Reviewed-on: https://go-review.googlesource.com/c/go/+/310731
Trust: Russ Cox <[email protected]>
Run-TryBot: Russ Cox <[email protected]>
Reviewed-by: Austin Clements <[email protected]>
Reviewed-by: Jay Conrod <[email protected]>

Author: rsc

.gitignore

@@ -37,6 +37,7 @@ _testmain.go
 /src/cmd/internal/objabi/zbootstrap.go
 /src/go/build/zcgo.go
 /src/go/doc/headscan
+/src/internal/buildcfg/zbootstrap.go
 /src/runtime/internal/sys/zversion.go
 /src/unicode/maketables
 /test.out

src/cmd/asm/internal/asm/endtoend_test.go

@@ -8,6 +8,7 @@ import (
 	"bufio"
 	"bytes"
 	"fmt"
+	"internal/buildcfg"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -19,7 +20,6 @@ import (
 
 	"cmd/asm/internal/lex"
 	"cmd/internal/obj"
-	"cmd/internal/objabi"
 )
 
 // An end-to-end test for the assembler: Do we print what we parse?
@@ -368,10 +368,10 @@ func Test386EndToEnd(t *testing.T) {
 }
 
 func TestARMEndToEnd(t *testing.T) {
-	defer func(old int) { objabi.GOARM = old }(objabi.GOARM)
+	defer func(old int) { buildcfg.GOARM = old }(buildcfg.GOARM)
 	for _, goarm := range []int{5, 6, 7} {
 		t.Logf("GOARM=%d", goarm)
-		objabi.GOARM = goarm
+		buildcfg.GOARM = goarm
 		testEndToEnd(t, "arm", "arm")
 		if goarm == 6 {
 			testEndToEnd(t, "arm", "armv6")

src/cmd/asm/internal/asm/operand_test.go

@@ -5,20 +5,20 @@
 package asm
 
 import (
+	"internal/buildcfg"
 	"strings"
 	"testing"
 
 	"cmd/asm/internal/arch"
 	"cmd/asm/internal/lex"
 	"cmd/internal/obj"
-	"cmd/internal/objabi"
 )
 
 // A simple in-out test: Do we print what we parse?
 
 func setArch(goarch string) (*arch.Arch, *obj.Link) {
-	objabi.GOOS = "linux" // obj can handle this OS for all architectures.
-	objabi.GOARCH = goarch
+	buildcfg.GOOS = "linux" // obj can handle this OS for all architectures.
+	buildcfg.GOARCH = goarch
 	architecture := arch.Set(goarch)
 	if architecture == nil {
 		panic("asm: unrecognized architecture " + goarch)

src/cmd/asm/internal/lex/input.go

@@ -6,6 +6,7 @@ package lex
 
 import (
 	"fmt"
+	"internal/buildcfg"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -49,7 +50,7 @@ func predefine(defines flags.MultiFlag) map[string]*Macro {
 	// Set macros for GOEXPERIMENTs so we can easily switch
 	// runtime assembly code based on them.
 	if *flags.CompilingRuntime {
-		for _, exp := range objabi.EnabledExperiments() {
+		for _, exp := range buildcfg.EnabledExperiments() {
 			// Define macro.
 			name := "GOEXPERIMENT_" + exp
 			macros[name] = &Macro{

src/cmd/asm/main.go

@@ -8,6 +8,7 @@ import (
 	"bufio"
 	"flag"
 	"fmt"
+	"internal/buildcfg"
 	"log"
 	"os"
 
@@ -18,14 +19,14 @@ import (
 
 	"cmd/internal/bio"
 	"cmd/internal/obj"
-	"cmd/internal/objabi"
 )
 
 func main() {
 	log.SetFlags(0)
 	log.SetPrefix("asm: ")
 
-	GOARCH := objabi.GOARCH
+	buildcfg.Check()
+	GOARCH := buildcfg.GOARCH
 
 	architecture := arch.Set(GOARCH)
 	if architecture == nil {
@@ -68,7 +69,7 @@ func main() {
 	defer buf.Close()
 
 	if !*flags.SymABIs {
-		fmt.Fprintf(buf, "go object %s %s %s\n", objabi.GOOS, objabi.GOARCH, objabi.Version)
+		fmt.Fprintf(buf, "go object %s %s %s\n", buildcfg.GOOS, buildcfg.GOARCH, buildcfg.Version)
 		fmt.Fprintf(buf, "!\n")
 	}
 

src/cmd/cgo/main.go

@@ -17,6 +17,7 @@ import (
 	"go/ast"
 	"go/printer"
 	"go/token"
+	"internal/buildcfg"
 	"io"
 	"io/ioutil"
 	"os"
@@ -414,8 +415,9 @@ func newPackage(args []string) *Package {
 	if s := os.Getenv("GOOS"); s != "" {
 		goos = s
 	}
-	gomips = objabi.GOMIPS
-	gomips64 = objabi.GOMIPS64
+	buildcfg.Check()
+	gomips = buildcfg.GOMIPS
+	gomips64 = buildcfg.GOMIPS64
 	ptrSize := ptrSizeMap[goarch]
 	if ptrSize == 0 {
 		fatalf("unknown ptrSize for $GOARCH %q", goarch)

src/cmd/compile/internal/amd64/ggen.go

@@ -11,11 +11,11 @@ import (
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/obj/x86"
-	"cmd/internal/objabi"
+	"internal/buildcfg"
 )
 
 // no floating point in note handlers on Plan 9
-var isPlan9 = objabi.GOOS == "plan9"
+var isPlan9 = buildcfg.GOOS == "plan9"
 
 // DUFFZERO consists of repeated blocks of 4 MOVUPSs + LEAQ,
 // See runtime/mkduff.go.
@@ -85,7 +85,7 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.
 		}
 		p = pp.Append(p, x86.AMOVQ, obj.TYPE_REG, x86.REG_R13, 0, obj.TYPE_MEM, x86.REG_SP, off)
 	} else if !isPlan9 && cnt <= int64(8*types.RegSize) {
-		if !objabi.Experiment.RegabiG && *state&x15 == 0 {
+		if !buildcfg.Experiment.RegabiG && *state&x15 == 0 {
 			p = pp.Append(p, x86.AXORPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_REG, x86.REG_X15, 0)
 			*state |= x15
 		}
@@ -98,7 +98,7 @@ func zerorange(pp *objw.Progs, p *obj.Prog, off, cnt int64, state *uint32) *obj.
 			p = pp.Append(p, x86.AMOVUPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_MEM, x86.REG_SP, off+cnt-int64(16))
 		}
 	} else if !isPlan9 && (cnt <= int64(128*types.RegSize)) {
-		if !objabi.Experiment.RegabiG && *state&x15 == 0 {
+		if !buildcfg.Experiment.RegabiG && *state&x15 == 0 {
 			p = pp.Append(p, x86.AXORPS, obj.TYPE_REG, x86.REG_X15, 0, obj.TYPE_REG, x86.REG_X15, 0)
 			*state |= x15
 		}

src/cmd/compile/internal/amd64/ssa.go

@@ -6,6 +6,7 @@ package amd64
 
 import (
 	"fmt"
+	"internal/buildcfg"
 	"math"
 
 	"cmd/compile/internal/base"
@@ -17,7 +18,6 @@ import (
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/obj/x86"
-	"cmd/internal/objabi"
 )
 
 // markMoves marks any MOVXconst ops that need to avoid clobbering flags.
@@ -825,7 +825,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.To.Reg = v.Args[0].Reg()
 		ssagen.AddAux2(&p.To, v, sc.Off64())
 	case ssa.OpAMD64MOVOstorezero:
-		if !objabi.Experiment.RegabiG || s.ABI != obj.ABIInternal {
+		if !buildcfg.Experiment.RegabiG || s.ABI != obj.ABIInternal {
 			// zero X15 manually
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 		}
@@ -916,7 +916,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = v.Reg()
 	case ssa.OpAMD64DUFFZERO:
-		if !objabi.Experiment.RegabiG || s.ABI != obj.ABIInternal {
+		if !buildcfg.Experiment.RegabiG || s.ABI != obj.ABIInternal {
 			// zero X15 manually
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 		}
@@ -999,20 +999,20 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 		// Closure pointer is DX.
 		ssagen.CheckLoweredGetClosurePtr(v)
 	case ssa.OpAMD64LoweredGetG:
-		if objabi.Experiment.RegabiG && s.ABI == obj.ABIInternal {
+		if buildcfg.Experiment.RegabiG && s.ABI == obj.ABIInternal {
 			v.Fatalf("LoweredGetG should not appear in ABIInternal")
 		}
 		r := v.Reg()
 		getgFromTLS(s, r)
 	case ssa.OpAMD64CALLstatic:
-		if objabi.Experiment.RegabiG && s.ABI == obj.ABI0 && v.Aux.(*ssa.AuxCall).Fn.ABI() == obj.ABIInternal {
+		if buildcfg.Experiment.RegabiG && s.ABI == obj.ABI0 && v.Aux.(*ssa.AuxCall).Fn.ABI() == obj.ABIInternal {
 			// zeroing X15 when entering ABIInternal from ABI0
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 			// set G register from TLS
 			getgFromTLS(s, x86.REG_R14)
 		}
 		s.Call(v)
-		if objabi.Experiment.RegabiG && s.ABI == obj.ABIInternal && v.Aux.(*ssa.AuxCall).Fn.ABI() == obj.ABI0 {
+		if buildcfg.Experiment.RegabiG && s.ABI == obj.ABIInternal && v.Aux.(*ssa.AuxCall).Fn.ABI() == obj.ABI0 {
 			// zeroing X15 when entering ABIInternal from ABI0
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 			// set G register from TLS
@@ -1306,7 +1306,7 @@ func ssaGenBlock(s *ssagen.State, b, next *ssa.Block) {
 	case ssa.BlockRet:
 		s.Prog(obj.ARET)
 	case ssa.BlockRetJmp:
-		if objabi.Experiment.RegabiG && s.ABI == obj.ABI0 && b.Aux.(*obj.LSym).ABI() == obj.ABIInternal {
+		if buildcfg.Experiment.RegabiG && s.ABI == obj.ABI0 && b.Aux.(*obj.LSym).ABI() == obj.ABIInternal {
 			// zeroing X15 when entering ABIInternal from ABI0
 			opregreg(s, x86.AXORPS, x86.REG_X15, x86.REG_X15)
 			// set G register from TLS

src/cmd/compile/internal/arm/galign.go

@@ -8,14 +8,14 @@ import (
 	"cmd/compile/internal/ssa"
 	"cmd/compile/internal/ssagen"
 	"cmd/internal/obj/arm"
-	"cmd/internal/objabi"
+	"internal/buildcfg"
 )
 
 func Init(arch *ssagen.ArchInfo) {
 	arch.LinkArch = &arm.Linkarm
 	arch.REGSP = arm.REGSP
 	arch.MAXWIDTH = (1 << 32) - 1
-	arch.SoftFloat = objabi.GOARM == 5
+	arch.SoftFloat = buildcfg.GOARM == 5
 	arch.ZeroRange = zerorange
 	arch.Ginsnop = ginsnop
 	arch.Ginsnopdefer = ginsnop

src/cmd/compile/internal/arm/ssa.go

@@ -6,6 +6,7 @@ package arm
 
 import (
 	"fmt"
+	"internal/buildcfg"
 	"math"
 	"math/bits"
 
@@ -17,7 +18,6 @@ import (
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/obj/arm"
-	"cmd/internal/objabi"
 )
 
 // loadByType returns the load instruction of the given type.
@@ -286,7 +286,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 	case ssa.OpARMANDconst, ssa.OpARMBICconst:
 		// try to optimize ANDconst and BICconst to BFC, which saves bytes and ticks
 		// BFC is only available on ARMv7, and its result and source are in the same register
-		if objabi.GOARM == 7 && v.Reg() == v.Args[0].Reg() {
+		if buildcfg.GOARM == 7 && v.Reg() == v.Args[0].Reg() {
 			var val uint32
 			if v.Op == ssa.OpARMANDconst {
 				val = ^uint32(v.AuxInt)
@@ -643,7 +643,7 @@ func ssaGenValue(s *ssagen.State, v *ssa.Value) {
 			default:
 			}
 		}
-		if objabi.GOARM >= 6 {
+		if buildcfg.GOARM >= 6 {
 			// generate more efficient "MOVB/MOVBU/MOVH/MOVHU Reg@>0, Reg" on ARMv6 & ARMv7
 			genshift(s, v.Op.Asm(), 0, v.Args[0].Reg(), v.Reg(), arm.SHIFT_RR, 0)
 			return

src/cmd/compile/internal/arm64/ggen.go

@@ -10,10 +10,10 @@ import (
 	"cmd/compile/internal/types"
 	"cmd/internal/obj"
 	"cmd/internal/obj/arm64"
-	"cmd/internal/objabi"
+	"internal/buildcfg"
 )
 
-var darwin = objabi.GOOS == "darwin" || objabi.GOOS == "ios"
+var darwin = buildcfg.GOOS == "darwin" || buildcfg.GOOS == "ios"
 
 func padframe(frame int64) int64 {
 	// arm64 requires that the frame size (not counting saved FP&LR)

src/cmd/compile/internal/base/flag.go

@@ -8,6 +8,7 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
+	"internal/buildcfg"
 	"io/ioutil"
 	"log"
 	"os"
@@ -146,7 +147,7 @@ func ParseFlags() {
 	Flag.LowerP = &Ctxt.Pkgpath
 	Flag.LowerV = &Ctxt.Debugvlog
 
-	Flag.Dwarf = objabi.GOARCH != "wasm"
+	Flag.Dwarf = buildcfg.GOARCH != "wasm"
 	Flag.DwarfBASEntries = &Ctxt.UseBASEntries
 	Flag.DwarfLocationLists = &Ctxt.Flag_locationlists
 	*Flag.DwarfLocationLists = true
@@ -168,14 +169,14 @@ func ParseFlags() {
 	registerFlags()
 	objabi.Flagparse(usage)
 
-	if Flag.MSan && !sys.MSanSupported(objabi.GOOS, objabi.GOARCH) {
-		log.Fatalf("%s/%s does not support -msan", objabi.GOOS, objabi.GOARCH)
+	if Flag.MSan && !sys.MSanSupported(buildcfg.GOOS, buildcfg.GOARCH) {
+		log.Fatalf("%s/%s does not support -msan", buildcfg.GOOS, buildcfg.GOARCH)
 	}
-	if Flag.Race && !sys.RaceDetectorSupported(objabi.GOOS, objabi.GOARCH) {
-		log.Fatalf("%s/%s does not support -race", objabi.GOOS, objabi.GOARCH)
+	if Flag.Race && !sys.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.PPC64, sys.RISCV64, sys.S390X) {
-		log.Fatalf("%s/%s does not support -shared", objabi.GOOS, objabi.GOARCH)
+		log.Fatalf("%s/%s does not support -shared", buildcfg.GOOS, buildcfg.GOARCH)
 	}
 	parseSpectre(Flag.Spectre) // left as string for RecordFlags
 
@@ -347,7 +348,7 @@ func concurrentBackendAllowed() bool {
 		return false
 	}
 	// TODO: Test and delete this condition.
-	if objabi.Experiment.FieldTrack {
+	if buildcfg.Experiment.FieldTrack {
 		return false
 	}
 	// TODO: fix races and enable the following flags
@@ -458,11 +459,11 @@ func parseSpectre(s string) {
 	}
 
 	if Flag.Cfg.SpectreIndex {
-		switch objabi.GOARCH {
+		switch buildcfg.GOARCH {
 		case "amd64":
 			// ok
 		default:
-			log.Fatalf("GOARCH=%s does not support -spectre=index", objabi.GOARCH)
+			log.Fatalf("GOARCH=%s does not support -spectre=index", buildcfg.GOARCH)
 		}
 	}
 }

src/cmd/compile/internal/base/print.go

@@ -6,12 +6,12 @@ package base
 
 import (
 	"fmt"
+	"internal/buildcfg"
 	"os"
 	"runtime/debug"
 	"sort"
 	"strings"
 
-	"cmd/internal/objabi"
 	"cmd/internal/src"
 )
 
@@ -217,7 +217,7 @@ func FatalfAt(pos src.XPos, format string, args ...interface{}) {
 		fmt.Printf("\n")
 
 		// If this is a released compiler version, ask for a bug report.
-		if strings.HasPrefix(objabi.Version, "go") {
+		if strings.HasPrefix(buildcfg.Version, "go") {
 			fmt.Printf("\n")
 			fmt.Printf("Please file a bug report including a short program that triggers the error.\n")
 			fmt.Printf("https://golang.org/issue/new\n")

src/cmd/compile/internal/dwarfgen/dwarf.go

@@ -8,6 +8,7 @@ import (
 	"bytes"
 	"flag"
 	"fmt"
+	"internal/buildcfg"
 	"sort"
 
 	"cmd/compile/internal/base"
@@ -278,7 +279,7 @@ func createSimpleVar(fnsym *obj.LSym, n *ir.Name) *dwarf.Var {
 		if base.Ctxt.FixedFrameSize() == 0 {
 			offs -= int64(types.PtrSize)
 		}
-		if objabi.FramePointerEnabled {
+		if buildcfg.FramePointerEnabled {
 			offs -= int64(types.PtrSize)
 		}