commit 407010ef0b858a7fa6e6e95abe652fdff923da9a
author Ian Lance Taylor <iant@golang.org> Sat Jul 27 16:14:16 2019 -0700
committer Ian Lance Taylor <iant@golang.org> Wed Jul 31 23:53:23 2019 +0000
tree 97726b69789a57f053512e87fc8d5ec9594cc5ad
parent e81b7315927d025a1eb3933542211b899880b982

cmd/go: only pass -fsplit-stack to gccgo if supported

Also add other gccgo options.

This ports CL 45695 and CL 48592 from the gofrontend repo to the gc repo.

CL 45695 (partial entry, other parts out of date and not ported):

    cmd/go: gccgo: consistent results

    Pass the -fdebug-prefix-map and -gno-record-gcc-switches compiler
    options to gccgo to generate consistent results.

CL 48592:

    cmd/go: use gccSupportsFlag for -fsplit-stack

    Don't assume that all (or only) 386/amd64 compilers support
    -fsplit-stack.

Fixes #33108

Change-Id: I61f9e5a67e4fb059f26750e97621d27afa566ec2
Reviewed-on: https://go-review.googlesource.com/c/go/+/187824
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>

src/cmd/go/internal/work/exec.go

diff --git a/src/cmd/go/internal/work/exec.go b/src/cmd/go/internal/work/exec.go
index 944b23f..b68f902 100644
--- a/src/cmd/go/internal/work/exec.go
+++ b/src/cmd/go/internal/work/exec.go
@@ -2532,8 +2532,7 @@
 	}
 
 	if cfg.BuildToolchainName == "gccgo" {
-		switch cfg.Goarch {
-		case "386", "amd64":
+		if b.gccSupportsFlag([]string{BuildToolchain.compiler()}, "-fsplit-stack") {
 			cgoCFLAGS = append(cgoCFLAGS, "-fsplit-stack")
 		}
 		cgoflags = append(cgoflags, "-gccgo")

src/cmd/go/internal/work/gccgo.go

diff --git a/src/cmd/go/internal/work/gccgo.go b/src/cmd/go/internal/work/gccgo.go
index 36726d3..24d856c 100644
--- a/src/cmd/go/internal/work/gccgo.go
+++ b/src/cmd/go/internal/work/gccgo.go
@@ -67,6 +67,8 @@
 	ofile = objdir + out
 	gcargs := []string{"-g"}
 	gcargs = append(gcargs, b.gccArchArgs()...)
+	gcargs = append(gcargs, "-fdebug-prefix-map="+b.WorkDir+"=/tmp/go-build")
+	gcargs = append(gcargs, "-gno-record-gcc-switches")
 	if pkgpath := gccgoPkgpath(p); pkgpath != "" {
 		gcargs = append(gcargs, "-fgo-pkgpath="+pkgpath)
 	}
@@ -528,12 +530,18 @@
 	if pkgpath := gccgoCleanPkgpath(p); pkgpath != "" {
 		defs = append(defs, `-D`, `GOPKGPATH="`+pkgpath+`"`)
 	}
-	switch cfg.Goarch {
-	case "386", "amd64":
+	compiler := envList("CC", cfg.DefaultCC(cfg.Goos, cfg.Goarch))
+	if b.gccSupportsFlag(compiler, "-fsplit-stack") {
 		defs = append(defs, "-fsplit-stack")
 	}
 	defs = tools.maybePIC(defs)
-	return b.run(a, p.Dir, p.ImportPath, nil, envList("CC", cfg.DefaultCC(cfg.Goos, cfg.Goarch)), "-Wall", "-g",
+	if b.gccSupportsFlag(compiler, "-fdebug-prefix-map=a=b") {
+		defs = append(defs, "-fdebug-prefix-map="+b.WorkDir+"=/tmp/go-build")
+	}
+	if b.gccSupportsFlag(compiler, "-gno-record-gcc-switches") {
+		defs = append(defs, "-gno-record-gcc-switches")
+	}
+	return b.run(a, p.Dir, p.ImportPath, nil, compiler, "-Wall", "-g",
 		"-I", a.Objdir, "-I", inc, "-o", ofile, defs, "-c", cfile)
 }