PR 10979

	* common.cc (Sort_commons::operator()): Stabilize sort when both
	entries are NULL.
	(Symbol_table::do_allocate_commons_list): When allocating common
	symbols, skip a symbol which is no longer common.
	* symtab.h (Symbol::is_common): Test whether the symbol comes from
	an object before checking its type.
	* testsuite/common_test_2.c: New file.
	* testsuite/common_test_3.c: New file.
	* testsuite/Makefile.am (check_PROGRAMS): Add common_test_2.
	(common_test_2_SOURCES, common_test_2_DEPENDENCIES): Define.
	(common_test_2_LDFLAGS, common_test_2_LDADD): Define.
	(common_test_2_pic.o, common_test_2.so): New targets.
	(common_test_3_pic.o, common_test_3.so): New targets.
	* testsuite/Makefile.in: Rebuild.

7 files changed, 146 insertions, 7 deletions

diff --git a/gold/ChangeLog b/gold/ChangeLog
index 508968d..027940e 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,6 +1,22 @@
 2009-12-30  Ian Lance Taylor  <iant@google.com>
 
 	PR 10979
+	* common.cc (Sort_commons::operator()): Stabilize sort when both
+	entries are NULL.
+	(Symbol_table::do_allocate_commons_list): When allocating common
+	symbols, skip a symbol which is no longer common.
+	* symtab.h (Symbol::is_common): Test whether the symbol comes from
+	an object before checking its type.
+	* testsuite/common_test_2.c: New file.
+	* testsuite/common_test_3.c: New file.
+	* testsuite/Makefile.am (check_PROGRAMS): Add common_test_2.
+	(common_test_2_SOURCES, common_test_2_DEPENDENCIES): Define.
+	(common_test_2_LDFLAGS, common_test_2_LDADD): Define.
+	(common_test_2_pic.o, common_test_2.so): New targets.
+	(common_test_3_pic.o, common_test_3.so): New targets.
+	* testsuite/Makefile.in: Rebuild.
+
+	PR 10979
 	* script.cc (read_input_script): If we see a new SECTIONS clause,
 	and we have added an input section, give an error.
 	* layout.h (class Layout): Add have_added_input_section function.
diff --git a/gold/common.cc b/gold/common.cc
index c4ff047..8859338 100644
--- a/gold/common.cc
+++ b/gold/common.cc
@@ -91,7 +91,16 @@ bool
 Sort_commons<size>::operator()(const Symbol* pa, const Symbol* pb) const
 {
   if (pa == NULL)
-    return false;
+    {
+      if (pb == NULL)
+	{
+	  // Stabilize sort.  The order really doesn't matter, because
+	  // these entries will be discarded, but we want to return
+	  // the same result every time we compare pa and pb.
+	  return pa < pb;
+	}
+      return false;
+    }
   if (pb == NULL)
     return true;
 
@@ -312,6 +321,17 @@ Symbol_table::do_allocate_commons_list(
       Symbol* sym = *p;
       if (sym == NULL)
 	break;
+
+      // Because we followed forwarding symbols above, but we didn't
+      // do it reliably before adding symbols to the list, it is
+      // possible for us to have the same symbol on the list twice.
+      // This can happen in the horrible case where a program defines
+      // a common symbol with the same name as a versioned libc
+      // symbol.  That will show up here as a symbol which has already
+      // been allocated and is therefore no longer a common symbol.
+      if (!sym->is_common())
+	continue;
+
       Sized_symbol<size>* ssym = this->get_sized_symbol<size>(sym);
 
       // Record the symbol in the map file now, before we change its
diff --git a/gold/symtab.h b/gold/symtab.h
index 8ee2091..f79fc8d 100644
--- a/gold/symtab.h
+++ b/gold/symtab.h
@@ -478,10 +478,10 @@ class Symbol
   bool
   is_common() const
   {
-    if (this->type_ == elfcpp::STT_COMMON)
-      return true;
     if (this->source_ != FROM_OBJECT)
       return false;
+    if (this->type_ == elfcpp::STT_COMMON)
+      return true;
     bool is_ordinary;
     unsigned int shndx = this->shndx(&is_ordinary);
     return !is_ordinary && Symbol::is_common_shndx(shndx);
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index 61934aa..7b5532e 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -407,6 +407,20 @@ common_test_1_DEPENDENCIES = gcctestdir/ld
 common_test_1_LDFLAGS = -Bgcctestdir/
 common_test_1_LDADD =
 
+check_PROGRAMS += common_test_2
+common_test_2_SOURCES = common_test_1.c
+common_test_2_DEPENDENCIES = common_test_2.so common_test_3.so gcctestdir/ld
+common_test_2_LDFLAGS = -Bgcctestdir/ -Wl,-R,.
+common_test_2_LDADD = common_test_2.so common_test_3.so
+common_test_2_pic.o: common_test_2.c
+	$(COMPILE) -c -fpic -o $@ $<
+common_test_2.so: common_test_2_pic.o common_test_3.so gcctestdir/ld
+	$(LINK) -Bgcctestdir/ -shared common_test_2_pic.o common_test_3.so
+common_test_3_pic.o: common_test_3.c
+	$(COMPILE) -c -fpic -o $@ $<
+common_test_3.so: common_test_3_pic.o ver_test_2.script gcctestdir/ld
+	$(LINK) -Bgcctestdir/ -shared common_test_3_pic.o -Wl,--version-script,$(srcdir)/ver_test_2.script
+
 check_PROGRAMS += exception_test
 check_PROGRAMS += exception_static_test
 check_PROGRAMS += exception_shared_1_test
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index 81b8b7f..291eab7 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -140,7 +140,8 @@ check_PROGRAMS = object_unittest$(EXEEXT) binary_unittest$(EXEEXT) \
 @FN_PTRS_IN_SO_WITHOUT_PIC_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@	two_file_mixed_2_shared_test
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_6 = two_file_strip_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	two_file_same_shared_strip_test \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@	common_test_1 exception_test \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	common_test_1 common_test_2 \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_static_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_shared_1_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_shared_2_test \
@@ -366,6 +367,7 @@ libgoldtest_a_OBJECTS = $(am_libgoldtest_a_OBJECTS)
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	two_file_strip_test$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	two_file_same_shared_strip_test$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	common_test_1$(EXEEXT) \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	common_test_2$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_test$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_static_test$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_shared_1_test$(EXEEXT) \
@@ -476,6 +478,12 @@ am__common_test_1_SOURCES_DIST = common_test_1.c
 common_test_1_OBJECTS = $(am_common_test_1_OBJECTS)
 common_test_1_LINK = $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
 	$(common_test_1_LDFLAGS) $(LDFLAGS) -o $@
+am__common_test_2_SOURCES_DIST = common_test_1.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@am_common_test_2_OBJECTS =  \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	common_test_1.$(OBJEXT)
+common_test_2_OBJECTS = $(am_common_test_2_OBJECTS)
+common_test_2_LINK = $(CCLD) $(AM_CFLAGS) $(CFLAGS) \
+	$(common_test_2_LDFLAGS) $(LDFLAGS) -o $@
 am__constructor_static_test_SOURCES_DIST = constructor_test.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am__objects_1 =  \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	constructor_test.$(OBJEXT)
@@ -1064,9 +1072,9 @@ CXXLINK = $(CXXLD) $(AM_CXXFLAGS) $(CXXFLAGS) $(AM_LDFLAGS) $(LDFLAGS) \
 SOURCES = $(libgoldtest_a_SOURCES) basic_pic_test.c basic_pie_test.c \
 	basic_static_pic_test.c basic_static_test.c basic_test.c \
 	$(binary_test_SOURCES) $(binary_unittest_SOURCES) \
-	$(common_test_1_SOURCES) $(constructor_static_test_SOURCES) \
-	$(constructor_test_SOURCES) $(copy_test_SOURCES) \
-	$(discard_locals_test_SOURCES) \
+	$(common_test_1_SOURCES) $(common_test_2_SOURCES) \
+	$(constructor_static_test_SOURCES) $(constructor_test_SOURCES) \
+	$(copy_test_SOURCES) $(discard_locals_test_SOURCES) \
 	$(exception_same_shared_test_SOURCES) \
 	$(exception_separate_shared_12_test_SOURCES) \
 	$(exception_separate_shared_21_test_SOURCES) \
@@ -1119,6 +1127,7 @@ DIST_SOURCES = $(libgoldtest_a_SOURCES) basic_pic_test.c \
 	basic_pie_test.c basic_static_pic_test.c basic_static_test.c \
 	basic_test.c $(am__binary_test_SOURCES_DIST) \
 	$(binary_unittest_SOURCES) $(am__common_test_1_SOURCES_DIST) \
+	$(am__common_test_2_SOURCES_DIST) \
 	$(am__constructor_static_test_SOURCES_DIST) \
 	$(am__constructor_test_SOURCES_DIST) \
 	$(am__copy_test_SOURCES_DIST) \
@@ -1505,6 +1514,10 @@ binary_unittest_SOURCES = binary_unittest.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_1_DEPENDENCIES = gcctestdir/ld
 @GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_1_LDFLAGS = -Bgcctestdir/
 @GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_1_LDADD = 
+@GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_2_SOURCES = common_test_1.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_2_DEPENDENCIES = common_test_2.so common_test_3.so gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_2_LDFLAGS = -Bgcctestdir/ -Wl,-R,.
+@GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_2_LDADD = common_test_2.so common_test_3.so
 @GCC_TRUE@@NATIVE_LINKER_TRUE@exception_test_SOURCES = \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_test_main.cc \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_test_1.cc \
@@ -1806,6 +1819,9 @@ binary_unittest$(EXEEXT): $(binary_unittest_OBJECTS) $(binary_unittest_DEPENDENC
 common_test_1$(EXEEXT): $(common_test_1_OBJECTS) $(common_test_1_DEPENDENCIES) 
 	@rm -f common_test_1$(EXEEXT)
 	$(common_test_1_LINK) $(common_test_1_OBJECTS) $(common_test_1_LDADD) $(LIBS)
+common_test_2$(EXEEXT): $(common_test_2_OBJECTS) $(common_test_2_DEPENDENCIES) 
+	@rm -f common_test_2$(EXEEXT)
+	$(common_test_2_LINK) $(common_test_2_OBJECTS) $(common_test_2_LDADD) $(LIBS)
 constructor_static_test$(EXEEXT): $(constructor_static_test_OBJECTS) $(constructor_static_test_DEPENDENCIES) 
 	@rm -f constructor_static_test$(EXEEXT)
 	$(constructor_static_test_LINK) $(constructor_static_test_OBJECTS) $(constructor_static_test_LDADD) $(LIBS)
@@ -2642,6 +2658,14 @@ uninstall-am:
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(TEST_STRIP) -o two_file_strip_test two_file_test
 @GCC_TRUE@@NATIVE_LINKER_TRUE@two_file_shared_strip.so: two_file_shared.so
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(TEST_STRIP) -S -o two_file_shared_strip.so two_file_shared.so
+@GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_2_pic.o: common_test_2.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(COMPILE) -c -fpic -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_2.so: common_test_2_pic.o common_test_3.so gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(LINK) -Bgcctestdir/ -shared common_test_2_pic.o common_test_3.so
+@GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_3_pic.o: common_test_3.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(COMPILE) -c -fpic -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@common_test_3.so: common_test_3_pic.o ver_test_2.script gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(LINK) -Bgcctestdir/ -shared common_test_3_pic.o -Wl,--version-script,$(srcdir)/ver_test_2.script
 @GCC_TRUE@@NATIVE_LINKER_TRUE@exception_test_1_pic.o: exception_test_1.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXCOMPILE) -c -fpic -o $@ $<
 @GCC_TRUE@@NATIVE_LINKER_TRUE@exception_test_2_pic.o: exception_test_2.cc
diff --git a/gold/testsuite/common_test_2.c b/gold/testsuite/common_test_2.c
new file mode 100644
index 0000000..ef6d83d
--- /dev/null
+++ b/gold/testsuite/common_test_2.c
@@ -0,0 +1,33 @@
+/* common_test_2.c -- test common symbol name conflicts
+
+   Copyright 2009 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor <iant@google.com>
+
+   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.  */
+
+/* Call a function.  The function will come from a shared library.  */
+
+extern void c1 (void);
+
+void fn (void);
+
+void
+fn (void)
+{
+  c1 ();
+}
diff --git a/gold/testsuite/common_test_3.c b/gold/testsuite/common_test_3.c
new file mode 100644
index 0000000..ba8960c
--- /dev/null
+++ b/gold/testsuite/common_test_3.c
@@ -0,0 +1,32 @@
+/* common_test_3.c -- test common symbol name conflicts
+
+   Copyright 2009 Free Software Foundation, Inc.
+   Written by Ian Lance Taylor <iant@google.com>
+
+   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.  */
+
+/* Define a function with a default version whose name is the same as
+   a common symbol.  This file will wind up in a shared library.  */
+
+void c1_v1 (void);
+
+void
+c1_v1 (void)
+{
+}
+__asm__ (".symver c1_v1,c1@@VER1");