2010-08-27 Doug Kwan <dougkwan@google.com>

	* gold/resolve.cc (Symbol_table::should_override): Let a weak
	reference override an existing dynamic weak reference.
	* testsuite/Makefile.am: Add new test dyn_weak_ref.
	* testsuite/Makefile.in: Regenerate.
	* testsuite/dyn_weak_ref.sh: New file.
	* testsuite/dyn_weak_ref_1.c: Ditto.
	* testsuite/dyn_weak_ref_2.c: Ditto.

7 files changed, 177 insertions, 5 deletions

diff --git a/gold/ChangeLog b/gold/ChangeLog
index 87eb2eb..667caae 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,13 @@
+2010-08-27  Doug Kwan  <dougkwan@google.com>
+
+	* gold/resolve.cc (Symbol_table::should_override): Let a weak
+	reference override an existing dynamic weak reference.
+	* testsuite/Makefile.am: Add new test dyn_weak_ref.
+	* testsuite/Makefile.in: Regenerate.
+	* testsuite/dyn_weak_ref.sh: New file.
+	* testsuite/dyn_weak_ref_1.c: Ditto.
+	* testsuite/dyn_weak_ref_2.c: Ditto.
+
 2010-08-27  Ian Lance Taylor  <iant@google.com>
 
 	* incremental.h (class Incremental_input_entry): Add virtual
diff --git a/gold/resolve.cc b/gold/resolve.cc
index 29d9d79..4864f1e 100644
--- a/gold/resolve.cc
+++ b/gold/resolve.cc
@@ -630,14 +630,21 @@ Symbol_table::should_override(const Symbol* to, unsigned int frombits,
     case UNDEF * 16 + WEAK_UNDEF:
     case WEAK_UNDEF * 16 + WEAK_UNDEF:
     case DYN_UNDEF * 16 + WEAK_UNDEF:
-    case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF:
     case COMMON * 16 + WEAK_UNDEF:
     case WEAK_COMMON * 16 + WEAK_UNDEF:
     case DYN_COMMON * 16 + WEAK_UNDEF:
     case DYN_WEAK_COMMON * 16 + WEAK_UNDEF:
-      // A new weak undefined reference tells us nothing.
+      // A new weak undefined reference tells us nothing unless the
+      // exisiting symbol is a dynamic weak reference.
       return false;
 
+    case DYN_WEAK_UNDEF * 16 + WEAK_UNDEF:
+      // A new weak reference overrides an existing dynamic weak reference.
+      // This is necessary because a dynamic weak reference remembers
+      // the old binding, which may not be weak.  If we keeps the existing
+      // dynamic weak reference, the weakness may be dropped in the output.
+      return true;
+
     case DYN_DEF * 16 + WEAK_UNDEF:
     case DYN_WEAK_DEF * 16 + WEAK_UNDEF:
       // For a dynamic def, we need to remember which kind of undef we see.
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index 875238f..bd8bfbd 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -1750,6 +1750,26 @@ strong_ref_weak_def_1.so: strong_ref_weak_def_1.o strong_ref_weak_def_2.so \
 strong_ref_weak_def.stdout: strong_ref_weak_def_1.so
 	$(TEST_READELF) -sWD $< > $@
 
+# Test that a strong weak reference remains strong if there is another
+# weak reference in a DSO.
+check_SCRIPTS += dyn_weak_ref.sh
+check_DATA += dyn_weak_ref.stdout
+MOSTLYCLEANFILES += dyn_weak_ref_1.so dyn_weak_ref_2.so \
+	dyn_weak_ref.stdout
+dyn_weak_ref_2.o: dyn_weak_ref_2.c
+	$(COMPILE) -o $@ -c -fPIC $<
+dyn_weak_ref_2.so: dyn_weak_ref_2.o gcctestdir/ld
+	gcctestdir/ld -shared -o $@ dyn_weak_ref_2.o
+dyn_weak_ref_1.o: dyn_weak_ref_1.c
+	$(COMPILE) -o $@ -c -fPIC $<
+# We intentionally put dyn_weak_ref_2.so in front of dyn_weak_ref_1.o
+# so that the weak ref there goes to gold's symbol table first.
+dyn_weak_ref_1.so: dyn_weak_ref_1.o dyn_weak_ref_2.so gcctestdir/ld
+	gcctestdir/ld -shared -o $@ dyn_weak_ref_2.so dyn_weak_ref_1.o
+dyn_weak_ref.stdout: dyn_weak_ref_1.so
+	$(TEST_READELF) -sWD $< > $@
+
+
 # Test that --start-lib and --end-lib function correctly.
 check_PROGRAMS += start_lib_test
 start_lib_test: start_lib_test_main.o libstart_lib_test.a start_lib_test_2.o start_lib_test_3.o \
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index 9405e27..29caa06 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -309,12 +309,16 @@ check_PROGRAMS = object_unittest$(EXEEXT) binary_unittest$(EXEEXT) \
 # symbol versioning is not used.
 
 # Test that strong reference to a weak symbol in a DSO remains strong.
+
+# Test that a strong weak reference remains strong if there is another
+# weak reference in a DSO.
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_27 = exclude_libs_test.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	hidden_test.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	retain_symbols_file_test.sh \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	no_version_test.sh \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@	strong_ref_weak_def.sh
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	strong_ref_weak_def.sh \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	dyn_weak_ref.sh
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_28 = exclude_libs_test.syms \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test.syms \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_relocatable_test1.syms \
@@ -322,7 +326,8 @@ check_PROGRAMS = object_unittest$(EXEEXT) binary_unittest$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	hidden_test.err \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	retain_symbols_file_test.stdout \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	no_version_test.stdout \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@	strong_ref_weak_def.stdout
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	strong_ref_weak_def.stdout \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	dyn_weak_ref.stdout
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_29 = exclude_libs_test.syms \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	libexclude_libs_test_1.a \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	libexclude_libs_test_2.a \
@@ -343,7 +348,10 @@ check_PROGRAMS = object_unittest$(EXEEXT) binary_unittest$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	no_version_test.stdout \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	strong_ref_weak_def_1.so \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	strong_ref_weak_def_2.so \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@	strong_ref_weak_def.stdout
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	strong_ref_weak_def.stdout \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	dyn_weak_ref_1.so \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	dyn_weak_ref_2.so \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	dyn_weak_ref.stdout
 @GCC_TRUE@@MCMODEL_MEDIUM_TRUE@@NATIVE_LINKER_TRUE@am__append_30 = large
 @GCC_FALSE@large_DEPENDENCIES =
 @MCMODEL_MEDIUM_FALSE@large_DEPENDENCIES =
@@ -3272,6 +3280,8 @@ no_version_test.sh.log: no_version_test.sh
 	@p='no_version_test.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 strong_ref_weak_def.sh.log: strong_ref_weak_def.sh
 	@p='strong_ref_weak_def.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
+dyn_weak_ref.sh.log: dyn_weak_ref.sh
+	@p='dyn_weak_ref.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 split_i386.sh.log: split_i386.sh
 	@p='split_i386.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 split_x86_64.sh.log: split_x86_64.sh
@@ -4448,6 +4458,18 @@ uninstall-am:
 @GCC_TRUE@@NATIVE_LINKER_TRUE@		strong_ref_weak_def_2.so
 @GCC_TRUE@@NATIVE_LINKER_TRUE@strong_ref_weak_def.stdout: strong_ref_weak_def_1.so
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(TEST_READELF) -sWD $< > $@
+@GCC_TRUE@@NATIVE_LINKER_TRUE@dyn_weak_ref_2.o: dyn_weak_ref_2.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(COMPILE) -o $@ -c -fPIC $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@dyn_weak_ref_2.so: dyn_weak_ref_2.o gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	gcctestdir/ld -shared -o $@ dyn_weak_ref_2.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@dyn_weak_ref_1.o: dyn_weak_ref_1.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(COMPILE) -o $@ -c -fPIC $<
+# We intentionally put dyn_weak_ref_2.so in front of dyn_weak_ref_1.o
+# so that the weak ref there goes to gold's symbol table first.
+@GCC_TRUE@@NATIVE_LINKER_TRUE@dyn_weak_ref_1.so: dyn_weak_ref_1.o dyn_weak_ref_2.so gcctestdir/ld
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	gcctestdir/ld -shared -o $@ dyn_weak_ref_2.so dyn_weak_ref_1.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@dyn_weak_ref.stdout: dyn_weak_ref_1.so
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(TEST_READELF) -sWD $< > $@
 @GCC_TRUE@@NATIVE_LINKER_TRUE@start_lib_test: start_lib_test_main.o libstart_lib_test.a start_lib_test_2.o start_lib_test_3.o \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	gcctestdir/ld
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(LINK) -Bgcctestdir/ -o $@ start_lib_test_main.o -L. -lstart_lib_test \
diff --git a/gold/testsuite/dyn_weak_ref.sh b/gold/testsuite/dyn_weak_ref.sh
new file mode 100755
index 0000000..b52efac
--- /dev/null
+++ b/gold/testsuite/dyn_weak_ref.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+
+# dyn_weak_ref.sh -- test weak reference remains weak in output even if
+# gold sees a dynamic weak reference before a static one.
+
+# Copyright 2010 Free Software Foundation, Inc.
+# Written by Doug Kwan <dougkwan@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.
+
+# This checks that the reference to 'weak_ref' have WEAK binding.
+
+check()
+{
+    file=$1
+    pattern=$2
+    found=`grep "$pattern" $file`
+    if test -z "$found"; then
+        echo "pattern \"$pattern\" not found in file $file."
+	echo $found
+        exit 1
+    fi
+}
+
+check dyn_weak_ref.stdout ".* WEAK .* UND.* weak_ref"
+
+exit 0
diff --git a/gold/testsuite/dyn_weak_ref_1.c b/gold/testsuite/dyn_weak_ref_1.c
new file mode 100644
index 0000000..fdd78dd
--- /dev/null
+++ b/gold/testsuite/dyn_weak_ref_1.c
@@ -0,0 +1,39 @@
+// dyn_weak_ref_1.c -- test that a weak ref remains weak in output when
+// there is a DSO with the same weak ref.
+
+// Copyright 2010 Free Software Foundation, Inc.
+// Written by Doug Kwan <dougkwan@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.
+
+// We test that we correctly deal with a weak reference to from both
+// a DSO and a weak reference to the same symbol in an executable.  The
+// symbol should remains weak.
+
+// This source is used to build an DSO that references the same weak
+// symbol as in a dependent DSO.
+
+extern void weak_ref (void) __attribute__((weak));
+
+void* ptr1 = weak_ref;
+
+int
+main (void)
+{
+  return 0;
+}
diff --git a/gold/testsuite/dyn_weak_ref_2.c b/gold/testsuite/dyn_weak_ref_2.c
new file mode 100644
index 0000000..8a087a1
--- /dev/null
+++ b/gold/testsuite/dyn_weak_ref_2.c
@@ -0,0 +1,32 @@
+// dyn_weak_ref_1.c -- test that a weak ref remains weak in output when
+// there is a DSO with the same weak ref.
+
+// Copyright 2010 Free Software Foundation, Inc.
+// Written by Doug Kwan <dougkwan@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.
+
+// We test that we correctly deal with a weak reference to from both
+// a DSO and a weak reference to the same symbol in an executable.  The
+// symbol should remains weak.
+
+// This source is used to build a DSO that contains a weak reference.
+
+extern void weak_ref (void) __attribute__((weak));
+
+void* ptr2 = weak_ref;