diff options
| -rw-r--r-- | misc/cgo/test/buildid_linux.go | 77 | ||||
| -rw-r--r-- | misc/cgo/test/cgo_linux_test.go | 5 | ||||
| -rw-r--r-- | src/cmd/go/build.go | 18 |
3 files changed, 97 insertions, 3 deletions
diff --git a/misc/cgo/test/buildid_linux.go b/misc/cgo/test/buildid_linux.go new file mode 100644 index 000000000..a3a86edfc --- /dev/null +++ b/misc/cgo/test/buildid_linux.go @@ -0,0 +1,77 @@ +// Copyright 2014 The Go Authors. All rights reserved. +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +package cgotest + +// Test that we have no more than one build ID. In the past we used +// to generate a separate build ID for each package using cgo, and the +// linker concatenated them all. We don't want that--we only want +// one. + +import ( + "bytes" + "debug/elf" + "os" + "testing" +) + +func testBuildID(t *testing.T) { + f, err := elf.Open("/proc/self/exe") + if err != nil { + if os.IsNotExist(err) { + t.Skip("no /proc/self/exe") + } + t.Fatalf("opening /proc/self/exe: ", err) + } + defer f.Close() + + c := 0 + for i, s := range f.Sections { + if s.Type != elf.SHT_NOTE { + continue + } + + d, err := s.Data() + if err != nil { + t.Logf("reading data of note section %d: %v", i, err) + continue + } + + for len(d) > 0 { + + // ELF standards differ as to the sizes in + // note sections. Both the GNU linker and + // gold always generate 32-bit sizes, so that + // is what we assume here. + + if len(d) < 12 { + t.Logf("note section %d too short (%d < 12)", i, len(d)) + continue + } + + namesz := f.ByteOrder.Uint32(d) + descsz := f.ByteOrder.Uint32(d[4:]) + typ := f.ByteOrder.Uint32(d[8:]) + + an := (namesz + 3) &^ 3 + ad := (descsz + 3) &^ 3 + + if int(12+an+ad) > len(d) { + t.Logf("note section %d too short for header (%d < 12 + align(%d,4) + align(%d,4))", i, len(d), namesz, descsz) + continue + } + + // 3 == NT_GNU_BUILD_ID + if typ == 3 && namesz == 4 && bytes.Equal(d[12:16], []byte("GNU\000")) { + c++ + } + + d = d[12+an+ad:] + } + } + + if c > 1 { + t.Errorf("found %d build ID notes", c) + } +} diff --git a/misc/cgo/test/cgo_linux_test.go b/misc/cgo/test/cgo_linux_test.go index 0a405c7a3..4fe0db1b2 100644 --- a/misc/cgo/test/cgo_linux_test.go +++ b/misc/cgo/test/cgo_linux_test.go @@ -6,5 +6,6 @@ package cgotest import "testing" -func TestSetgid(t *testing.T) { testSetgid(t) } -func Test6997(t *testing.T) { test6997(t) } +func TestSetgid(t *testing.T) { testSetgid(t) } +func Test6997(t *testing.T) { test6997(t) } +func TestBuildID(t *testing.T) { testBuildID(t) } diff --git a/src/cmd/go/build.go b/src/cmd/go/build.go index fa9262c0f..b39364ed8 100644 --- a/src/cmd/go/build.go +++ b/src/cmd/go/build.go @@ -2312,7 +2312,23 @@ func (b *builder) cgo(p *Package, cgoExe, obj string, gccfiles, gxxfiles, mfiles nonGccObjs = append(nonGccObjs, f) } } - if err := b.gccld(p, ofile, stringList(bareLDFLAGS, "-Wl,-r", "-nostdlib", staticLibs), gccObjs); err != nil { + ldflags := stringList(bareLDFLAGS, "-Wl,-r", "-nostdlib", staticLibs) + + // Some systems, such as Ubuntu, always add --build-id to + // every link, but we don't want a build ID since we are + // producing an object file. On some of those system a plain + // -r (not -Wl,-r) will turn off --build-id, but clang 3.0 + // doesn't support a plain -r. I don't know how to turn off + // --build-id when using clang other than passing a trailing + // --build-id=none. So that is what we do, but only on + // systems likely to support it, which is to say, systems that + // normally use gold or the GNU linker. + switch goos { + case "android", "dragonfly", "freebsd", "linux", "netbsd", "openbsd": + ldflags = append(ldflags, "-Wl,--build-id=none") + } + + if err := b.gccld(p, ofile, ldflags, gccObjs); err != nil { return nil, nil, err } |