commit dc6df1b07093ffa0568a581251e8ddd38f707ed6

Author: Shawn Walker-Salas <[email protected]>

Date:   Thu Sep 17 15:47:20 2015 -0700

    cmd/go: elide -rpath when not applicable and used via LDFLAGS

    Some linker flags should only be applied when performing the final

    linking step for a shared library or executable, etc. In other

    contexts, they're either invalid, or meaningless to apply (so should

    not be specified).

    When an external linker is used (either directly by Go or by the

    compiler driver used by cgo), -rpath and -rpath-link should only be

    specified in the final linking step.  On platforms such as Solaris,

    ld(1) will reject its use in any other scenario (such as when linking

    relocatable objects).

    This change is necessary because Go does not currently offer a way to

    specify LDFLAGS based on when they should be applied.

    Fixes #12115

    Change-Id: If35a18d8eee8ec7ddcca2d4ccd41ab6ffcf93b41

    Reviewed-on: https://go-review.googlesource.com/14674

    Reviewed-by: Minux Ma <[email protected]>

    Run-TryBot: Minux Ma <[email protected]>

    TryBot-Result: Gobot Gobot <[email protected]>

    Reviewed-by: Ian Lance Taylor <[email protected]>

diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go

index df74338..0c2bc5f 100644

--- a/src/cmd/go/build.go

+++ b/src/cmd/go/build.go

@@ -2943,7 +2943,9 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, cgofi

 	var linkobj []string

 	var bareLDFLAGS []string

-	// filter out -lsomelib, -l somelib, *.{so,dll,dylib}, and (on Darwin) -framework X

+	// When linking relocatable objects, various flags need to be

+	// filtered out as they are inapplicable and can cause some linkers

+	// to fail.

 	for i := 0; i < len(cgoLDFLAGS); i++ {

 		f := cgoLDFLAGS[i]

 		switch {

@@ -2959,7 +2961,6 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, cgofi

 		case strings.HasSuffix(f, ".dylib"),

 			strings.HasSuffix(f, ".so"),

 			strings.HasSuffix(f, ".dll"):

-			continue

 		// Remove any -fsanitize=foo flags.

 		// Otherwise the compiler driver thinks that we are doing final link

 		// and links sanitizer runtime into the object file. But we are not doing

@@ -2968,6 +2969,16 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, pcCFLAGS, pcLDFLAGS, cgofi

 		// See issue 8788 for details.

 		case strings.HasPrefix(f, "-fsanitize="):

 			continue

+		// runpath flags not applicable unless building a shared

+		// object or executable; see issue 12115 for details.  This

+		// is necessary as Go currently does not offer a way to

+		// specify the set of LDFLAGS that only apply to shared

+		// objects.

+		case strings.HasPrefix(f, "-Wl,-rpath"):

+			if f == "-Wl,-rpath" || f == "-Wl,-rpath-link" {

+				// Skip following argument to -rpath* too.

+				i++

+			}

 		default:

 			bareLDFLAGS = append(bareLDFLAGS, f)

 		}