diff options
| author | Joel Sing <joel@sing.id.au> | 2019-03-28 00:53:19 +1100 |
|---|---|---|
| committer | Ian Lance Taylor <iant@golang.org> | 2019-03-29 17:46:01 +0000 |
| commit | c90f6dd4966087d85e1dcafc02b64ecb0c7f4e7e (patch) | |
| tree | 709477b170978e76c21db2c69a77c314e1a8d8db | |
| parent | 6966b67510df9a96dd798e5f6e26c5ad6dd925a5 (diff) | |
| download | go-c90f6dd4966087d85e1dcafc02b64ecb0c7f4e7e.tar.xz | |
cmd/link: permit duplicate weak symbols
Permit weak symbols to be duplicates - most external linkers allow
this and there are various situations where they can occur (including
retpoline and retguard).
Fixes #29563
Change-Id: I355493c847fbc8f670a85a643db65a4cf8f9883d
Reviewed-on: https://go-review.googlesource.com/c/go/+/169658
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
| -rw-r--r-- | misc/cgo/test/testdata/issue29563.go | 12 | ||||
| -rw-r--r-- | misc/cgo/test/testdata/issue29563/weak.go | 13 | ||||
| -rw-r--r-- | misc/cgo/test/testdata/issue29563/weak1.c | 11 | ||||
| -rw-r--r-- | misc/cgo/test/testdata/issue29563/weak2.c | 11 | ||||
| -rw-r--r-- | src/cmd/link/internal/loadelf/ldelf.go | 5 |
5 files changed, 52 insertions, 0 deletions
diff --git a/misc/cgo/test/testdata/issue29563.go b/misc/cgo/test/testdata/issue29563.go new file mode 100644 index 0000000000..84def3ca44 --- /dev/null +++ b/misc/cgo/test/testdata/issue29563.go @@ -0,0 +1,12 @@ +// Copyright 2019 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. + +// +build !windows + +// Issue 29563: internal linker fails on duplicate weak symbols. +// No runtime test; just make sure it compiles. + +package cgotest + +import _ "cgotest/issue29563" diff --git a/misc/cgo/test/testdata/issue29563/weak.go b/misc/cgo/test/testdata/issue29563/weak.go new file mode 100644 index 0000000000..21cf635cca --- /dev/null +++ b/misc/cgo/test/testdata/issue29563/weak.go @@ -0,0 +1,13 @@ +// Copyright 2019 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 issue29563 + +//int foo1(); +//int foo2(); +import "C" + +func Bar() int { + return int(C.foo1()) + int(C.foo2()) +} diff --git a/misc/cgo/test/testdata/issue29563/weak1.c b/misc/cgo/test/testdata/issue29563/weak1.c new file mode 100644 index 0000000000..86a22734ad --- /dev/null +++ b/misc/cgo/test/testdata/issue29563/weak1.c @@ -0,0 +1,11 @@ +// Copyright 2019 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. + +extern int weaksym __attribute__((__weak__)); +int weaksym = 42; + +int foo1() +{ + return weaksym; +} diff --git a/misc/cgo/test/testdata/issue29563/weak2.c b/misc/cgo/test/testdata/issue29563/weak2.c new file mode 100644 index 0000000000..e01eae8b58 --- /dev/null +++ b/misc/cgo/test/testdata/issue29563/weak2.c @@ -0,0 +1,11 @@ +// Copyright 2019 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. + +extern int weaksym __attribute__((__weak__)); +int weaksym = 42; + +int foo2() +{ + return weaksym; +} diff --git a/src/cmd/link/internal/loadelf/ldelf.go b/src/cmd/link/internal/loadelf/ldelf.go index d85d91948a..916b7cf9f2 100644 --- a/src/cmd/link/internal/loadelf/ldelf.go +++ b/src/cmd/link/internal/loadelf/ldelf.go @@ -1088,6 +1088,11 @@ func readelfsym(arch *sys.Arch, syms *sym.Symbols, elfobj *ElfObj, i int, elfsym if elfsym.other == 2 { s.Attr |= sym.AttrVisibilityHidden } + + // Allow weak symbols to be duplicated when already defined. + if s.Outer != nil { + s.Attr |= sym.AttrDuplicateOK + } } default: |