[release-branch.go1.4] cmd/go: if -no-pie doesn't work, try -nopie

This is a backport of https://golang.org/cl/49710 to the Go 1.4 branch.

Original CL description:
    GCC says -no-pie, clang says -nopie.

Updates #21042

Change-Id: I67b755ccb0149324098b79e07ee4bbc49429c44c
Reviewed-on: https://go-review.googlesource.com/49711
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

1 files changed, 25 insertions, 19 deletions

diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go
index 93bc2200f1a..13676589537 100644
--- a/src/cmd/go/build.go
+++ b/src/cmd/go/build.go
@@ -2121,34 +2121,40 @@ func (b *builder) ccompilerCmd(envvar, defcmd, objdir string) []string {
 	return a
 }
 
-// On systems with PIE (position independent executables) enabled by default,
-// -no-pie must be passed when doing a partial link with -Wl,-r. But -no-pie is
-// not supported by all compilers.
-func (b *builder) gccSupportsNoPie() bool {
+// gccNoPie returns the flag to use to request non-PIE. On systems
+// with PIE (position independent executables) enabled by default,
+// -no-pie must be passed when doing a partial link with -Wl,-r.
+// But -no-pie is not supported by all compilers, and clang spells it -nopie.
+func (b *builder) gccNoPie() string {
 	if goos != "linux" {
 		// On some BSD platforms, error messages from the
 		// compiler make it to the console despite cmd.Std*
 		// all being nil. As -no-pie is only required on linux
 		// systems so far, we only test there.
-		return false
+		return ""
 	}
 	src := filepath.Join(b.work, "trivial.c")
 	if err := ioutil.WriteFile(src, []byte{}, 0666); err != nil {
-		return false
+		return ""
 	}
-	cmdArgs := b.gccCmd(b.work)
-	cmdArgs = append(cmdArgs, "-no-pie", "-c", "trivial.c")
-	if buildN || buildX {
-		b.showcmd(b.work, "%s", joinUnambiguously(cmdArgs))
-		if buildN {
-			return false
+	for _, nopie := range []string{"-no-pie", "-nopie"} {
+		cmdArgs := b.gccCmd(b.work)
+		cmdArgs = append(cmdArgs, nopie, "-c", "trivial.c")
+		if buildN || buildX {
+			b.showcmd(b.work, "%s", joinUnambiguously(cmdArgs))
+			if buildN {
+				return ""
+			}
+		}
+		cmd := exec.Command(cmdArgs[0], cmdArgs[1:]...)
+		cmd.Dir = b.work
+		cmd.Env = envForDir(cmd.Dir)
+		err := cmd.Run()
+		if err == nil {
+			return nopie
 		}
 	}
-	cmd := exec.Command(cmdArgs[0], cmdArgs[1:]...)
-	cmd.Dir = b.work
-	cmd.Env = envForDir(cmd.Dir)
-	err := cmd.Run()
-	return err == nil
+	return ""
 }
 
 // gccArchArgs returns arguments to pass to gcc based on the architecture.
@@ -2399,8 +2405,8 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, gccfi
 	}
 	ldflags := stringList(bareLDFLAGS, "-Wl,-r", "-nostdlib", staticLibs)
 
-	if b.gccSupportsNoPie() {
-		ldflags = append(ldflags, "-no-pie")
+	if flag := b.gccNoPie(); flag != "" {
+		ldflags = append(ldflags, flag)
 	}
 
 	// Some systems, such as Ubuntu, always add --build-id to