cmd/link: avoid duplicate DT_NEEDED entries
When adding a new library entry, ensure we record it as seen to avoid
adding duplicates of it.
Fixes #39256
Change-Id: Id309adf80c533d78fd485517c18bc9ab5f1d29fb
Reviewed-on: https://go-review.googlesource.com/c/go/+/235257
Run-TryBot: Joel Sing <joel@sing.id.au>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/src/cmd/link/internal/ld/elf.go b/src/cmd/link/internal/ld/elf.go
index 957f5081..2862f65 100644
--- a/src/cmd/link/internal/ld/elf.go
+++ b/src/cmd/link/internal/ld/elf.go
@@ -2378,6 +2378,7 @@
if target.Arch.Family == sys.AMD64 && !cgoeDynamic && dil != "" && !seenlib[dil] {
du := ldr.MakeSymbolUpdater(syms.Dynamic)
Elfwritedynent(target.Arch, du, DT_NEEDED, uint64(dstru.Addstring(dil)))
+ seenlib[dil] = true
}
} else {
diff --git a/src/cmd/link/internal/ld/elf_test.go b/src/cmd/link/internal/ld/elf_test.go
index 8e86beb..37f0e77 100644
--- a/src/cmd/link/internal/ld/elf_test.go
+++ b/src/cmd/link/internal/ld/elf_test.go
@@ -13,6 +13,7 @@
"os"
"os/exec"
"path/filepath"
+ "runtime"
"testing"
)
@@ -77,3 +78,57 @@
t.Fatalf("Unexpected sh info, want greater than 0, got: %d", section.Info)
}
}
+
+func TestNoDuplicateNeededEntries(t *testing.T) {
+ testenv.MustHaveGoBuild(t)
+ testenv.MustHaveCGO(t)
+
+ // run this test on just a small set of platforms (no need to test it
+ // across the board given the nature of the test).
+ pair := runtime.GOOS + "-" + runtime.GOARCH
+ switch pair {
+ case "linux-amd64", "freebsd-amd64", "openbsd-amd64":
+ default:
+ t.Skip("no need for test on " + pair)
+ }
+
+ t.Parallel()
+
+ dir, err := ioutil.TempDir("", "no-dup-needed")
+ if err != nil {
+ t.Fatalf("Failed to create temp dir: %v", err)
+ }
+ defer os.RemoveAll(dir)
+
+ wd, err := os.Getwd()
+ if err != nil {
+ t.Fatalf("Failed to get working directory: %v", err)
+ }
+
+ path := filepath.Join(dir, "x")
+ argv := []string{"build", "-o", path, filepath.Join(wd, "testdata", "issue39256")}
+ out, err := exec.Command(testenv.GoToolPath(t), argv...).CombinedOutput()
+ if err != nil {
+ t.Fatalf("Build failure: %s\n%s\n", err, string(out))
+ }
+
+ f, err := elf.Open(path)
+ if err != nil {
+ t.Fatalf("Failed to open ELF file: %v", err)
+ }
+ libs, err := f.ImportedLibraries()
+ if err != nil {
+ t.Fatalf("Failed to read imported libraries: %v", err)
+ }
+
+ var count int
+ for _, lib := range libs {
+ if lib == "libc.so" {
+ count++
+ }
+ }
+
+ if got, want := count, 1; got != want {
+ t.Errorf("Got %d entries for `libc.so`, want %d", got, want)
+ }
+}
diff --git a/src/cmd/link/internal/ld/testdata/issue39256/x.go b/src/cmd/link/internal/ld/testdata/issue39256/x.go
new file mode 100644
index 0000000..d8562ad
--- /dev/null
+++ b/src/cmd/link/internal/ld/testdata/issue39256/x.go
@@ -0,0 +1,20 @@
+// Copyright 2020 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 main
+
+import (
+ _ "unsafe"
+)
+
+//go:cgo_import_dynamic libc_getpid getpid "libc.so"
+//go:cgo_import_dynamic libc_kill kill "libc.so"
+//go:cgo_import_dynamic libc_close close "libc.so"
+//go:cgo_import_dynamic libc_open open "libc.so"
+
+func trampoline()
+
+func main() {
+ trampoline()
+}
diff --git a/src/cmd/link/internal/ld/testdata/issue39256/x.s b/src/cmd/link/internal/ld/testdata/issue39256/x.s
new file mode 100644
index 0000000..41a54b2
--- /dev/null
+++ b/src/cmd/link/internal/ld/testdata/issue39256/x.s
@@ -0,0 +1,10 @@
+// Copyright 2020 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.
+
+TEXT ·trampoline(SB),0,$0
+ CALL libc_getpid(SB)
+ CALL libc_kill(SB)
+ CALL libc_open(SB)
+ CALL libc_close(SB)
+ RET
