From 65eb8c79be0c71f9b52d14563c0817fc5ca33c0d Mon Sep 17 00:00:00 2001 From: Sriraman Tallam Date: Thu, 23 Apr 2015 13:48:24 -0700 Subject: [PATCH] Add option --weak-unresolved-symbols to treat unresolved as weak references. This patch adds option --weak-unresolved-symbols to treat unresolved symbols as weak references. This is helpful when we want the link to succeed with unresolved symbols and the dynamic loader to not complain at run-time. Option --warn-unresolved-symbols lets the link succeed but could fail at run-time with unresolved symbol warnings especially when the unresolved symbols have GOT entries and dynamic relocations against them, like when -fPIE is used. 2015-04-23 Sriraman Tallam * options.h (--weak-unresolved-symbols): New option. * symtab.cc (Symbol_table::sized_write_globals): Change symbol binding to weak with new option. * symtab.h (is_weak_undefined): Check for new option. (is_strong_undefined): Check for new option. * testsuite/Makefile.am (weak_unresolved_symbols_test): New test. * testsuite/Makefile.in: Regenerate. * testsuite/weak_unresolved_symbols_test.cc: New file. --- gold/testsuite/weak_unresolved_symbols_test.cc | 45 ++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 gold/testsuite/weak_unresolved_symbols_test.cc diff --git a/gold/testsuite/weak_unresolved_symbols_test.cc b/gold/testsuite/weak_unresolved_symbols_test.cc new file mode 100644 index 0000000..ec2c462 --- /dev/null +++ b/gold/testsuite/weak_unresolved_symbols_test.cc @@ -0,0 +1,45 @@ +// weak_unresolved_symbols_test.cc -- a test case for gold + +// Copyright (C) 2015 Free Software Foundation, Inc. +// Written by Sriraman Tallam . + +// This file is part of gold. + +// This program is free software; you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation; either version 3 of the License, or +// (at your option) any later version. + +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this program; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, +// MA 02110-1301, USA. + +// Test --weak-unresolved-symbols. Symbol foo remains unresolved but +// with -fPIE, needs a GOT entry and has a dynsym entry and a dynamic +// relocation against it created. This will fail to link and run without +// --weak-unresolved-symbols. With --warn-unresolved-symbols, it will link +// but the dynamic linker will complain that foo(_Z3foov) is unresolved. + +extern int foo(); + +int bar() { + return 0; +} + +int (*p)() = &bar; + +int main() { + if (p == &foo) + { + foo(); + } + else + (*p)(); + return 0; +} -- 2.7.4