runtime: break out system-specific constants into package sys

runtime/internal/sys will hold system-, architecture- and config-
specific constants.

Updates #11647

Change-Id: I6db29c312556087a42e8d2bdd9af40d157c56b54
Reviewed-on: https://go-review.googlesource.com/16817
Reviewed-by: Russ Cox <[email protected]>

Author: matloob

.gitignore

@@ -29,7 +29,7 @@ src/cmd/cgo/zdefaultcc.go
 src/cmd/go/zdefaultcc.go
 src/cmd/internal/obj/zbootstrap.go
 src/go/doc/headscan
-src/runtime/zversion.go
+src/runtime/internal/sys/zversion.go
 src/unicode/maketables
 src/*.*/
 test/pass.out

src/cmd/compile/internal/gc/racewalk.go

@@ -31,7 +31,7 @@ import (
 
 // Do not instrument the following packages at all,
 // at best instrumentation would cause infinite recursion.
-var omit_pkgs = []string{"runtime/internal/atomic", "runtime", "runtime/race", "runtime/msan"}
+var omit_pkgs = []string{"runtime/internal/atomic", "runtime/internal/sys", "runtime", "runtime/race", "runtime/msan"}
 
 // Only insert racefuncenter/racefuncexit into the following packages.
 // Memory accesses in the packages are either uninteresting or will cause false positives.

src/cmd/dist/build.go

@@ -463,7 +463,7 @@ var deptab = []struct {
 	{"cmd/go", []string{
 		"zdefaultcc.go",
 	}},
-	{"runtime", []string{
+	{"runtime/internal/sys", []string{
 		"zversion.go",
 	}},
 }

src/cmd/dist/buildruntime.go

@@ -17,23 +17,23 @@ import (
 // mkzversion writes zversion.go:
 //
 //	package runtime
-//	const defaultGoroot = <goroot>
-//	const theVersion = <version>
-//	const goexperiment = <goexperiment>
-//	const stackGuardMultiplier = <multiplier value>
-//	const buildVersion = <build version>
+//	const DefaultGoroot = <goroot>
+//	const TheVersion = <version>
+//	const Goexperiment = <goexperiment>
+//	const StackGuardMultiplier = <multiplier value>
+//	const BuildVersion = <build version>
 //
 func mkzversion(dir, file string) {
 	out := fmt.Sprintf(
 		"// auto generated by go tool dist\n"+
 			"\n"+
-			"package runtime\n"+
+			"package sys\n"+
 			"\n"+
-			"const defaultGoroot = `%s`\n"+
-			"const theVersion = `%s`\n"+
-			"const goexperiment = `%s`\n"+
-			"const stackGuardMultiplier = %d\n\n"+
-			"var buildVersion = theVersion\n", goroot_final, findgoversion(), os.Getenv("GOEXPERIMENT"), stackGuardMultiplier())
+			"const DefaultGoroot = `%s`\n"+
+			"const TheVersion = `%s`\n"+
+			"const Goexperiment = `%s`\n"+
+			"const StackGuardMultiplier = %d\n\n"+
+			"var BuildVersion = TheVersion\n", goroot_final, findgoversion(), os.Getenv("GOEXPERIMENT"), stackGuardMultiplier())
 
 	writefile(out, file, writeSkipSame)
 }

src/cmd/dist/deps.go

@@ -36,7 +36,8 @@ var pkgDeps = map[string][]string{
 	// L0 is the lowest level, core, nearly unavoidable packages.
 	"errors":                  {},
 	"io":                      {"errors", "sync"},
-	"runtime":                 {"unsafe", "runtime/internal/atomic"},
+	"runtime":                 {"unsafe", "runtime/internal/atomic", "runtime/internal/sys"},
+	"runtime/internal/sys":    {},
 	"runtime/internal/atomic": {"unsafe"},
 	"sync":        {"runtime", "sync/atomic", "unsafe"},
 	"sync/atomic": {"unsafe"},

src/go/build/deps_test.go

@@ -4,11 +4,14 @@
 
 package runtime
 
-import "unsafe"
+import (
+	"runtime/internal/sys"
+	"unsafe"
+)
 
 const (
-	c0 = uintptr((8-ptrSize)/4*2860486313 + (ptrSize-4)/4*33054211828000289)
-	c1 = uintptr((8-ptrSize)/4*3267000013 + (ptrSize-4)/4*23344194077549503)
+	c0 = uintptr((8-sys.PtrSize)/4*2860486313 + (sys.PtrSize-4)/4*33054211828000289)
+	c1 = uintptr((8-sys.PtrSize)/4*3267000013 + (sys.PtrSize-4)/4*23344194077549503)
 )
 
 // type algorithms - known to compiler
@@ -301,7 +304,7 @@ func memclrBytes(b []byte) {
 	memclr(s.array, uintptr(s.len))
 }
 
-const hashRandomBytes = ptrSize / 4 * 64
+const hashRandomBytes = sys.PtrSize / 4 * 64
 
 // used in asm_{386,amd64}.s to seed the hash function
 var aeskeysched [hashRandomBytes]byte
@@ -324,7 +327,7 @@ func init() {
 		getRandomData(aeskeysched[:])
 		return
 	}
-	getRandomData((*[len(hashkey) * ptrSize]byte)(unsafe.Pointer(&hashkey))[:])
+	getRandomData((*[len(hashkey) * sys.PtrSize]byte)(unsafe.Pointer(&hashkey))[:])
 	hashkey[0] |= 1 // make sure these numbers are odd
 	hashkey[1] |= 1
 	hashkey[2] |= 1

src/runtime/alg.go

@@ -79,7 +79,10 @@
 
 package runtime
 
-import "unsafe"
+import (
+	"runtime/internal/sys"
+	"unsafe"
+)
 
 // Call from Go to C.
 //go:nosplit
@@ -220,22 +223,22 @@ func cgocallbackg1() {
 	case "arm":
 		// On arm, stack frame is two words and there's a saved LR between
 		// SP and the stack frame and between the stack frame and the arguments.
-		cb = (*args)(unsafe.Pointer(sp + 4*ptrSize))
+		cb = (*args)(unsafe.Pointer(sp + 4*sys.PtrSize))
 	case "arm64":
 		// On arm64, stack frame is four words and there's a saved LR between
 		// SP and the stack frame and between the stack frame and the arguments.
-		cb = (*args)(unsafe.Pointer(sp + 5*ptrSize))
+		cb = (*args)(unsafe.Pointer(sp + 5*sys.PtrSize))
 	case "amd64":
 		// On amd64, stack frame is one word, plus caller PC.
 		if framepointer_enabled {
 			// In this case, there's also saved BP.
-			cb = (*args)(unsafe.Pointer(sp + 3*ptrSize))
+			cb = (*args)(unsafe.Pointer(sp + 3*sys.PtrSize))
 			break
 		}
-		cb = (*args)(unsafe.Pointer(sp + 2*ptrSize))
+		cb = (*args)(unsafe.Pointer(sp + 2*sys.PtrSize))
 	case "386":
 		// On 386, stack frame is three words, plus caller PC.
-		cb = (*args)(unsafe.Pointer(sp + 4*ptrSize))
+		cb = (*args)(unsafe.Pointer(sp + 4*sys.PtrSize))
 	case "ppc64", "ppc64le":
 		// On ppc64, the callback arguments are in the arguments area of
 		// cgocallback's stack frame. The stack looks like this:
@@ -252,7 +255,7 @@ func cgocallbackg1() {
 		// | cgocallback_gofunc +------------------------------+ <- sp + minFrameSize
 		// |                    | fixed frame area             |
 		// +--------------------+------------------------------+ <- sp
-		cb = (*args)(unsafe.Pointer(sp + 2*minFrameSize + 2*ptrSize))
+		cb = (*args)(unsafe.Pointer(sp + 2*sys.MinFrameSize + 2*sys.PtrSize))
 	}
 
 	// Invoke callback.
@@ -291,7 +294,7 @@ func unwindm(restore *bool) {
 	default:
 		throw("unwindm not implemented")
 	case "386", "amd64", "arm", "ppc64", "ppc64le":
-		sched.sp = *(*uintptr)(unsafe.Pointer(sched.sp + minFrameSize))
+		sched.sp = *(*uintptr)(unsafe.Pointer(sched.sp + sys.MinFrameSize))
 	case "arm64":
 		sched.sp = *(*uintptr)(unsafe.Pointer(sched.sp + 16))
 	}
@@ -437,7 +440,7 @@ func cgoCheckArg(t *_type, p unsafe.Pointer, indir, top bool) {
 		if inheap(uintptr(unsafe.Pointer(it))) {
 			panic(errorString(cgoCheckPointerFail))
 		}
-		p = *(*unsafe.Pointer)(unsafe.Pointer(uintptr(p) + ptrSize))
+		p = *(*unsafe.Pointer)(unsafe.Pointer(uintptr(p) + sys.PtrSize))
 		if !cgoIsGoPointer(p) {
 			return
 		}
@@ -505,9 +508,9 @@ func cgoCheckUnknownPointer(p unsafe.Pointer) {
 			return
 		}
 		n := span.elemsize
-		for i := uintptr(0); i < n; i += ptrSize {
+		for i := uintptr(0); i < n; i += sys.PtrSize {
 			bits := hbits.bits()
-			if i >= 2*ptrSize && bits&bitMarked == 0 {
+			if i >= 2*sys.PtrSize && bits&bitMarked == 0 {
 				// No more possible pointers.
 				break
 			}

src/runtime/arch_386.go

@@ -8,6 +8,7 @@ package runtime
 
 import (
 	"runtime/internal/atomic"
+	"runtime/internal/sys"
 	"unsafe"
 )
 
@@ -115,7 +116,7 @@ func GostringW(w []uint16) (s string) {
 var Gostringnocopy = gostringnocopy
 var Maxstring = &maxstring
 
-type Uintreg uintreg
+type Uintreg sys.Uintreg
 
 var Open = open
 var Close = closefd
@@ -125,7 +126,7 @@ var Write = write
 func Envs() []string     { return envs }
 func SetEnvs(e []string) { envs = e }
 
-var BigEndian = _BigEndian
+var BigEndian = sys.BigEndian
 
 // For benchmarking.
 
@@ -156,7 +157,7 @@ func BenchSetType(n int, x interface{}) {
 	})
 }
 
-const PtrSize = ptrSize
+const PtrSize = sys.PtrSize
 
 var TestingAssertE2I2GC = &testingAssertE2I2GC
 var TestingAssertE2T2GC = &testingAssertE2T2GC

src/runtime/arch_amd64.go

@@ -130,6 +130,8 @@ of the run-time system.
 */
 package runtime
 
+import "runtime/internal/sys"
+
 // Caller reports file and line number information about function invocations on
 // the calling goroutine's stack.  The argument skip is the number of stack frames
 // to ascend, with 0 identifying the caller of Caller.  (For historical reasons the
@@ -199,20 +201,20 @@ func GOROOT() string {
 	if s != "" {
 		return s
 	}
-	return defaultGoroot
+	return sys.DefaultGoroot
 }
 
 // Version returns the Go tree's version string.
 // It is either the commit hash and date at the time of the build or,
 // when possible, a release tag like "go1.3".
 func Version() string {
-	return theVersion
+	return sys.TheVersion
 }
 
 // GOOS is the running program's operating system target:
 // one of darwin, freebsd, linux, and so on.
-const GOOS string = theGoos
+const GOOS string = sys.TheGoos
 
 // GOARCH is the running program's architecture target:
 // 386, amd64, or arm.
-const GOARCH string = theGoarch
+const GOARCH string = sys.TheGoarch