cmd/dist, runtime: Make stack guard larger for non-optimized builds

Kind of a hack, but makes the non-optimized builds pass.

Fixes #10079

Change-Id: I26f41c546867f8f3f16d953dc043e784768f2aff
Reviewed-on: https://go-review.googlesource.com/9552Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/dist/buildruntime.go

@@ -7,6 +7,7 @@ package main
 import (
 	"fmt"
 	"os"
+	"strings"
 )
 
 /*
@@ -18,6 +19,9 @@ import (
 //	package runtime
 //	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(
@@ -28,7 +32,8 @@ func mkzversion(dir, file string) {
 			"const defaultGoroot = `%s`\n"+
 			"const theVersion = `%s`\n"+
 			"const goexperiment = `%s`\n"+
-			"var buildVersion = theVersion\n", goroot_final, findgoversion(), os.Getenv("GOEXPERIMENT"))
+			"const stackGuardMultiplier = %d\n"+
+			"var buildVersion = theVersion\n", goroot_final, findgoversion(), os.Getenv("GOEXPERIMENT"), stackGuardMultiplier())
 
 	writefile(out, file, 0)
 }
@@ -44,6 +49,7 @@ func mkzversion(dir, file string) {
 //	const defaultGOARCH = runtime.GOARCH
 //	const defaultGO_EXTLINK_ENABLED = <goextlinkenabled>
 //	const version = <version>
+//	const stackGuardMultiplier = <multiplier value>
 //	const goexperiment = <goexperiment>
 //
 // The use of runtime.GOOS and runtime.GOARCH makes sure that
@@ -70,8 +76,21 @@ func mkzbootstrap(file string) {
 			"const defaultGOARCH = runtime.GOARCH\n"+
 			"const defaultGO_EXTLINK_ENABLED = `%s`\n"+
 			"const version = `%s`\n"+
+			"const stackGuardMultiplier = %d\n"+
 			"const goexperiment = `%s`\n",
-		goroot_final, go386, goarm, goextlinkenabled, findgoversion(), os.Getenv("GOEXPERIMENT"))
+		goroot_final, go386, goarm, goextlinkenabled, findgoversion(), stackGuardMultiplier(), os.Getenv("GOEXPERIMENT"))
 
 	writefile(out, file, 0)
 }
+
+// stackGuardMultiplier returns a multiplier to apply to the default
+// stack guard size.  Larger multipliers are used for non-optimized
+// builds that have larger stack frames.
+func stackGuardMultiplier() int {
+	for _, s := range strings.Split(os.Getenv("GO_GCFLAGS"), " ") {
+		if s == "-N" {
+			return 2
+		}
+	}
+	return 1
+}

src/cmd/internal/obj/stack.go

@@ -41,7 +41,7 @@ const (
 	STACKSYSTEM = 0
 	StackSystem = STACKSYSTEM
 	StackBig    = 4096
-	StackGuard  = 640 + StackSystem
+	StackGuard  = 640*stackGuardMultiplier + StackSystem
 	StackSmall  = 128
 	StackLimit  = StackGuard - StackSystem - StackSmall
 )

src/runtime/proc1.go

@@ -691,7 +691,7 @@ func mstart() {
 		// Cgo may have left stack size in stack.hi.
 		size := _g_.stack.hi
 		if size == 0 {
-			size = 8192
+			size = 8192 * stackGuardMultiplier
 		}
 		_g_.stack.hi = uintptr(noescape(unsafe.Pointer(&size)))
 		_g_.stack.lo = _g_.stack.hi - size + 1024
@@ -890,7 +890,7 @@ func allocm(_p_ *p, fn func()) *m {
 	if iscgo || GOOS == "solaris" || GOOS == "windows" || GOOS == "plan9" {
 		mp.g0 = malg(-1)
 	} else {
-		mp.g0 = malg(8192)
+		mp.g0 = malg(8192 * stackGuardMultiplier)
 	}
 	mp.g0.m = mp
 

src/runtime/stack2.go

@@ -84,7 +84,7 @@ const (
 
 	// The stack guard is a pointer this many bytes above the
 	// bottom of the stack.
-	_StackGuard = 640 + _StackSystem
+	_StackGuard = 640*stackGuardMultiplier + _StackSystem
 
 	// After a stack split check the SP is allowed to be this
 	// many bytes below the stack guard.  This saves an instruction