2008-04-04 Cary Coutant <ccoutant@google.com>

	* symtab.h (Symbol::is_weak_undefined): New function.
	(Symbol::is_strong_undefined): New function.
	(Symbol::is_absolute): New function.
	(Symbol::needs_plt_entry): Exclude weak undefined symbols.
	(Symbol::needs_dynamic_reloc): Exclude weak undefined and
	absolute symbols.
	* testsuite/Makefile.am (check_PROGRAMS): Add weak_undef_test.
	(weak_undef_test): New target.
	* testsuite/Makefile.in: Rebuild.
	* testsuite/weak_undef_file1.cc: New file.
	* testsuite/weak_undef_file2.cc: New file.
	* testsuite/weak_undef_test.cc: New file.

7 files changed, 227 insertions, 5 deletions

diff --git a/gold/ChangeLog b/gold/ChangeLog
index ecd4e55..be2da35 100644
--- a/gold/ChangeLog
+++ b/gold/ChangeLog
@@ -1,3 +1,18 @@
+2008-04-04  Cary Coutant  <ccoutant@google.com>
+
+	* symtab.h (Symbol::is_weak_undefined): New function.
+	(Symbol::is_strong_undefined): New function.
+	(Symbol::is_absolute): New function.
+	(Symbol::needs_plt_entry): Exclude weak undefined symbols.
+	(Symbol::needs_dynamic_reloc): Exclude weak undefined and
+	absolute symbols.
+	* testsuite/Makefile.am (check_PROGRAMS): Add weak_undef_test.
+	(weak_undef_test): New target.
+	* testsuite/Makefile.in: Rebuild.
+	* testsuite/weak_undef_file1.cc: New file.
+	* testsuite/weak_undef_file2.cc: New file.
+	* testsuite/weak_undef_test.cc: New file.
+
 2008-04-03  Craig Silverstein  <csilvers@google.com>
 
 	* compressed_output.h (class Output_compressed_section): Use
diff --git a/gold/symtab.h b/gold/symtab.h
index bd41794..e262cd4 100644
--- a/gold/symtab.h
+++ b/gold/symtab.h
@@ -405,6 +405,31 @@ class Symbol
     return this->source_ == FROM_OBJECT && this->shndx() == elfcpp::SHN_UNDEF;
   }
 
+  // Return whether this is a weak undefined symbol.
+  bool
+  is_weak_undefined() const
+  {
+    return (this->source_ == FROM_OBJECT
+            && this->binding() == elfcpp::STB_WEAK
+            && this->shndx() == elfcpp::SHN_UNDEF);
+  }
+
+  // Return whether this is a strong (i.e., not weak) undefined symbol.
+  bool
+  is_strong_undefined() const
+  {
+    return (this->source_ == FROM_OBJECT
+            && this->binding() != elfcpp::STB_WEAK
+            && this->shndx() == elfcpp::SHN_UNDEF);
+  }
+
+  // Return whether this is an absolute symbol.
+  bool
+  is_absolute() const
+  {
+    return this->source_ == FROM_OBJECT && this->shndx() == elfcpp::SHN_ABS;
+  }
+
   // Return whether this is a common symbol.
   bool
   is_common() const
@@ -453,7 +478,7 @@ class Symbol
     return (!parameters->doing_static_link()
             && this->type() == elfcpp::STT_FUNC
             && (this->is_from_dynobj()
-                || this->is_undefined()
+                || this->is_strong_undefined()
                 || this->is_preemptible()));
   }
 
@@ -481,6 +506,11 @@ class Symbol
     if (parameters->doing_static_link())
       return false;
 
+    // A reference to a weak undefined symbol or to an absolute symbol
+    // does not need a dynamic relocation.
+    if (this->is_weak_undefined() || this->is_absolute())
+      return false;
+
     // An absolute reference within a position-independent output file
     // will need a dynamic relocation.
     if ((flags & ABSOLUTE_REF)
diff --git a/gold/testsuite/Makefile.am b/gold/testsuite/Makefile.am
index d478ed4..35c7d14 100644
--- a/gold/testsuite/Makefile.am
+++ b/gold/testsuite/Makefile.am
@@ -347,6 +347,20 @@ weak_test_SOURCES = weak_test.cc
 weak_test_DEPENDENCIES = gcctestdir/ld
 weak_test_LDFLAGS = -Bgcctestdir/
 
+check_PROGRAMS += weak_undef_test
+weak_undef_test_SOURCES = weak_undef_test.cc
+weak_undef_test_DEPENDENCIES = gcctestdir/ld weak_undef_lib.so alt/weak_undef_lib.so
+weak_undef_test_LDFLAGS = -Bgcctestdir/ -Wl,-R,alt
+weak_undef_test_LDADD = -L . weak_undef_lib.so
+weak_undef_file1.o: weak_undef_file1.cc
+	$(CXXCOMPILE) -c -fpic -o $@ $<
+weak_undef_file2.o: weak_undef_file2.cc
+	$(CXXCOMPILE) -c -fpic -o $@ $<
+weak_undef_lib.so: weak_undef_file1.o
+	$(CXXLINK) -Bgcctestdir/ -shared weak_undef_file1.o
+alt/weak_undef_lib.so: weak_undef_file2.o
+	test -d alt || mkdir -p alt
+	$(CXXLINK) -Bgcctestdir/ -shared weak_undef_file2.o
 
 if TLS
 
diff --git a/gold/testsuite/Makefile.in b/gold/testsuite/Makefile.in
index dfa6bfb..05e5c5e 100644
--- a/gold/testsuite/Makefile.in
+++ b/gold/testsuite/Makefile.in
@@ -110,7 +110,7 @@ check_PROGRAMS = object_unittest$(EXEEXT) binary_unittest$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_same_shared_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_separate_shared_12_test \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_separate_shared_21_test \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@	weak_test
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	weak_test weak_undef_test
 @GCC_FALSE@common_test_1_DEPENDENCIES = libgoldtest.a ../libgold.a \
 @GCC_FALSE@	../../libiberty/libiberty.a $(am__DEPENDENCIES_1) \
 @GCC_FALSE@	$(am__DEPENDENCIES_1)
@@ -297,7 +297,8 @@ libgoldtest_a_OBJECTS = $(am_libgoldtest_a_OBJECTS)
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_same_shared_test$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_separate_shared_12_test$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_separate_shared_21_test$(EXEEXT) \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@	weak_test$(EXEEXT)
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	weak_test$(EXEEXT) \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	weak_undef_test$(EXEEXT)
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@am__EXEEXT_4 =  \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@	tls_test$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@	tls_pic_test$(EXEEXT) \
@@ -635,6 +636,10 @@ am__weak_test_SOURCES_DIST = weak_test.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	weak_test.$(OBJEXT)
 weak_test_OBJECTS = $(am_weak_test_OBJECTS)
 weak_test_LDADD = $(LDADD)
+am__weak_undef_test_SOURCES_DIST = weak_undef_test.cc
+@GCC_TRUE@@NATIVE_LINKER_TRUE@am_weak_undef_test_OBJECTS =  \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	weak_undef_test.$(OBJEXT)
+weak_undef_test_OBJECTS = $(am_weak_undef_test_OBJECTS)
 DEFAULT_INCLUDES = -I. -I$(srcdir) -I$(top_builddir)
 depcomp = $(SHELL) $(top_srcdir)/../depcomp
 am__depfiles_maybe = depfiles
@@ -684,7 +689,8 @@ SOURCES = $(libgoldtest_a_SOURCES) basic_pic_test.c \
 	$(two_file_shared_2_test_SOURCES) \
 	$(two_file_static_test_SOURCES) $(two_file_test_SOURCES) \
 	$(ver_test_SOURCES) $(ver_test_2_SOURCES) \
-	$(ver_test_6_SOURCES) $(weak_test_SOURCES)
+	$(ver_test_6_SOURCES) $(weak_test_SOURCES) \
+	$(weak_undef_test_SOURCES)
 DIST_SOURCES = $(libgoldtest_a_SOURCES) basic_pic_test.c \
 	basic_static_pic_test.c basic_static_test.c basic_test.c \
 	$(am__binary_test_SOURCES_DIST) $(binary_unittest_SOURCES) \
@@ -729,7 +735,8 @@ DIST_SOURCES = $(libgoldtest_a_SOURCES) basic_pic_test.c \
 	$(am__two_file_static_test_SOURCES_DIST) \
 	$(am__two_file_test_SOURCES_DIST) $(am__ver_test_SOURCES_DIST) \
 	$(am__ver_test_2_SOURCES_DIST) $(am__ver_test_6_SOURCES_DIST) \
-	$(am__weak_test_SOURCES_DIST)
+	$(am__weak_test_SOURCES_DIST) \
+	$(am__weak_undef_test_SOURCES_DIST)
 ETAGS = etags
 CTAGS = ctags
 DISTFILES = $(DIST_COMMON) $(DIST_SOURCES) $(TEXINFOS) $(EXTRA_DIST)
@@ -1070,6 +1077,10 @@ binary_unittest_SOURCES = binary_unittest.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@weak_test_SOURCES = weak_test.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@weak_test_DEPENDENCIES = gcctestdir/ld
 @GCC_TRUE@@NATIVE_LINKER_TRUE@weak_test_LDFLAGS = -Bgcctestdir/
+@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_undef_test_SOURCES = weak_undef_test.cc
+@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_undef_test_DEPENDENCIES = gcctestdir/ld weak_undef_lib.so alt/weak_undef_lib.so
+@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_undef_test_LDFLAGS = -Bgcctestdir/ -Wl,-R,alt
+@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_undef_test_LDADD = -L . weak_undef_lib.so
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@tls_test_SOURCES = tls_test.cc tls_test_file2.cc tls_test_main.cc tls_test.h
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@tls_test_DEPENDENCIES = gcctestdir/ld
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@tls_test_LDFLAGS = -Bgcctestdir/
@@ -1357,6 +1368,9 @@ ver_test_6$(EXEEXT): $(ver_test_6_OBJECTS) $(ver_test_6_DEPENDENCIES)
 weak_test$(EXEEXT): $(weak_test_OBJECTS) $(weak_test_DEPENDENCIES) 
 	@rm -f weak_test$(EXEEXT)
 	$(CXXLINK) $(weak_test_LDFLAGS) $(weak_test_OBJECTS) $(weak_test_LDADD) $(LIBS)
+weak_undef_test$(EXEEXT): $(weak_undef_test_OBJECTS) $(weak_undef_test_DEPENDENCIES) 
+	@rm -f weak_undef_test$(EXEEXT)
+	$(CXXLINK) $(weak_undef_test_LDFLAGS) $(weak_undef_test_OBJECTS) $(weak_undef_test_LDADD) $(LIBS)
 
 mostlyclean-compile:
 	-rm -f *.$(OBJEXT)
@@ -1400,6 +1414,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ver_test_main.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/ver_test_main_2.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/weak_test.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/weak_undef_test.Po@am__quote@
 
 .c.o:
 @am__fastdepCC_TRUE@	if $(COMPILE) -MT $@ -MD -MP -MF "$(DEPDIR)/$*.Tpo" -c -o $@ $<; \
@@ -1743,6 +1758,15 @@ uninstall-am: uninstall-info-am
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXLINK) -Bgcctestdir/ -shared exception_test_2_pic.o
 @GCC_TRUE@@NATIVE_LINKER_TRUE@exception_shared.so: exception_test_1_pic.o exception_test_2_pic.o gcctestdir/ld
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXLINK) -Bgcctestdir/ -shared exception_test_1_pic.o exception_test_2_pic.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_undef_file1.o: weak_undef_file1.cc
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXCOMPILE) -c -fpic -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_undef_file2.o: weak_undef_file2.cc
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXCOMPILE) -c -fpic -o $@ $<
+@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_undef_lib.so: weak_undef_file1.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXLINK) -Bgcctestdir/ -shared weak_undef_file1.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@alt/weak_undef_lib.so: weak_undef_file2.o
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	test -d alt || mkdir -p alt
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(CXXLINK) -Bgcctestdir/ -shared weak_undef_file2.o
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@tls_test_pic.o: tls_test.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@	$(CXXCOMPILE) -c -fpic -o $@ $<
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@TLS_TRUE@tls_test_file2_pic.o: tls_test_file2.cc
diff --git a/gold/testsuite/weak_undef_file1.cc b/gold/testsuite/weak_undef_file1.cc
new file mode 100644
index 0000000..58ab53b
--- /dev/null
+++ b/gold/testsuite/weak_undef_file1.cc
@@ -0,0 +1,45 @@
+// weak_undef_file1.cc -- test handling of weak undefined symbols for gold
+
+// Copyright 2008 Free Software Foundation, Inc.
+// Written by Cary Coutant <ccoutant@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 weak undefined symbols.
+// We need to make sure that the symbol is resolved to zero
+// by the linker and that no dynamic relocation is generated.
+
+// This source is used to build a shared library that defines
+// an arbitrary symbol other than the weak undefined symbol
+// referenced by the main program.  The main program will be
+// linked with this library so that the symbol remains undefined.
+// Through the use of the embedded RPATH, the program will load
+// an alternate shared library that does define the symbol,
+// so that we can detect whether the symbol was left for runtime
+// resolution.
+
+
+#include <cstdio>
+
+int is_such_symbol_ = 0;
+
+int
+t1()
+{
+  return is_such_symbol_;
+}
diff --git a/gold/testsuite/weak_undef_file2.cc b/gold/testsuite/weak_undef_file2.cc
new file mode 100644
index 0000000..69629ad
--- /dev/null
+++ b/gold/testsuite/weak_undef_file2.cc
@@ -0,0 +1,46 @@
+// weak_undef_file1.cc -- test handling of weak undefined symbols for gold
+
+// Copyright 2008 Free Software Foundation, Inc.
+// Written by Cary Coutant <ccoutant@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 weak undefined symbols.
+// We need to make sure that the symbol is resolved to zero
+// by the linker and that no dynamic relocation is generated.
+
+// This source is used to build a shared library that defines
+// the weak undefined symbol referenced by the main program.
+// The main program will be linked with a library that does not
+// provide this definition, so that the symbol remains undefined.
+// Through the use of the embedded RPATH, the program will load
+// this alternate shared library that does define the symbol,
+// so that we can detect whether the symbol was left for runtime
+// resolution.
+
+
+#include <cstdio>
+
+int is_such_symbol_ = 0;
+int no_such_symbol_ = 1;
+
+int
+t1()
+{
+  return no_such_symbol_;
+}
diff --git a/gold/testsuite/weak_undef_test.cc b/gold/testsuite/weak_undef_test.cc
new file mode 100644
index 0000000..1a6e17f
--- /dev/null
+++ b/gold/testsuite/weak_undef_test.cc
@@ -0,0 +1,48 @@
+// weak_undef_test.cc -- test handling of weak undefined symbols for gold
+
+// Copyright 2008 Free Software Foundation, Inc.
+// Written by Cary Coutant <ccoutant@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 weak undefined symbols.
+// We need to make sure that the symbol is resolved to zero
+// by the linker and that no dynamic relocation is generated.
+
+// This file will be linked with a shared library that does not
+// define the symbol, so that the symbol remains undefined.
+// Through the use of LD_LIBRARY_PATH, the program will load
+// an alternate shared library that does define the symbol,
+// so that we can detect whether the symbol was left for runtime
+// resolution.
+
+
+#include <cstdio>
+
+extern int no_such_symbol_ __attribute__ ((weak));
+
+int
+main()
+{
+  if (&no_such_symbol_ != NULL)
+    {
+      fprintf(stderr, "FAILED the weak undef test: &no_such_symbol_ is not NULL\n");
+      return 1;
+    }
+  return 0;
+}