Index: gold/i386.cc
===================================================================
RCS file: /cvs/src/src/gold/i386.cc,v
retrieving revision 1.86
diff -u -u -p -r1.86 i386.cc
--- gold/i386.cc	24 Mar 2009 00:31:28 -0000	1.86
+++ gold/i386.cc	5 Jun 2009 01:42:09 -0000
@@ -155,6 +155,19 @@ class Target_i386 : public Target_freebs
   do_is_defined_by_abi(const Symbol* sym) const
   { return strcmp(sym->name(), "___tls_get_addr") == 0; }
 
+  // Return whether a symbol name implies a local label.  The UnixWare
+  // 2.1 cc generates temporary symbols that start with .X, so we
+  // recognize them here.  FIXME: do other SVR4 compilers also use .X?.
+  // If so, we should move the .X recognition into
+  // Target::do_is_local_label_name.
+  bool
+  do_is_local_label_name(const char* name) const
+  {
+    if (name[0] == '.' && name[1] == 'X')
+      return true;
+    return Target::do_is_local_label_name(name);
+  }
+
   // Return the size of the GOT section.
   section_size_type
   got_size()
Index: gold/object.cc
===================================================================
RCS file: /cvs/src/src/gold/object.cc,v
retrieving revision 1.91
diff -u -u -p -r1.91 object.cc
--- gold/object.cc	22 May 2009 18:31:22 -0000	1.91
+++ gold/object.cc	5 Jun 2009 01:42:09 -0000
@@ -1432,6 +1432,7 @@ Sized_relobj<size, big_endian>::do_count
   unsigned int dyncount = 0;
   // Skip the first, dummy, symbol.
   psyms += sym_size;
+  bool discard_locals = parameters->options().discard_locals();
   for (unsigned int i = 1; i < loccount; ++i, psyms += sym_size)
     {
       elfcpp::Sym<size, big_endian> sym(psyms);
@@ -1476,8 +1477,28 @@ Sized_relobj<size, big_endian>::do_count
 	  continue;
 	}
 
-      // Add the symbol to the symbol table string pool.
+      // If --discard-locals option is used, discard all temporary local
+      // symbols.  These symbols start with system-specific local label
+      // prefixes, typically .L for ELF system.  We want to be compatible
+      // with GNU ld so here we essentially use the same check in
+      // bfd_is_local_label().  The code is different because we already
+      // know that:
+      //
+      //   - the symbol is local and thus cannot have global or weak binding.
+      //   - the symbol is not a section symbol.
+      //   - the symbol has a name.
+      //
       const char* name = pnames + sym.get_st_name();
+      if (discard_locals
+	  && sym.get_st_type() != elfcpp::STT_FILE
+	  && parameters->target().is_local_label_name(name))
+	{
+	  lv.set_no_output_symtab_entry();
+          gold_assert(!lv.needs_output_dynsym_entry());
+	  continue;
+	}
+
+      // Add the symbol to the symbol table string pool.
       pool->add(name, true, NULL);
       ++count;
 
Index: gold/options.h
===================================================================
RCS file: /cvs/src/src/gold/options.h,v
retrieving revision 1.98
diff -u -u -p -r1.98 options.h
--- gold/options.h	19 May 2009 22:14:17 -0000	1.98
+++ gold/options.h	5 Jun 2009 01:42:09 -0000
@@ -645,6 +645,9 @@ class General_options
               N_("Try to detect violations of the One Definition Rule"),
               NULL);
 
+  DEFINE_bool(discard_locals, options::TWO_DASHES, 'X', false,
+              N_("Delete all temporary local symbols"), NULL);
+
   DEFINE_bool(dynamic_list_data, options::TWO_DASHES, '\0', false,
               N_("Add data symbols to dynamic symbols"), NULL);
 
Index: gold/target.h
===================================================================
RCS file: /cvs/src/src/gold/target.h,v
retrieving revision 1.32
diff -u -u -p -r1.32 target.h
--- gold/target.h	24 Mar 2009 00:31:29 -0000	1.32
+++ gold/target.h	5 Jun 2009 01:42:09 -0000
@@ -173,6 +173,12 @@ class Target
   adjust_elf_header(unsigned char* view, int len) const
   { return this->do_adjust_elf_header(view, len); }
 
+  // Return whether NAME is a local label name.  This is used to implement the
+  // --discard-locals options.
+  bool
+  is_local_label_name(const char* name) const
+  { return this->do_is_local_label_name(name); }
+
  protected:
   // This struct holds the constant information for a child class.  We
   // use a struct to avoid the overhead of virtual function calls for
@@ -239,6 +245,33 @@ class Target
   do_adjust_elf_header(unsigned char*, int) const
   { }
 
+  // Virtual function which may be overriden by the child class.
+  virtual bool
+  do_is_local_label_name(const char* name) const
+  {
+    // The logic is the same as that in _bfd_elf_is_local_label_name().
+   
+    // Normal local symbols start with ``.L''.
+    if (name[0] == '.' && name[1] == 'L')
+      return true;
+
+    // At least some SVR4 compilers (e.g., UnixWare 2.1 cc) generate
+    // DWARF debugging symbols starting with ``..''.
+    if (name[0] == '.' && name[1] == '.')
+      return true;
+
+    // gcc will sometimes generate symbols beginning with ``_.L_'' when
+    // emitting DWARF debugging output.  I suspect this is actually a
+    // small bug in gcc (it calls ASM_OUTPUT_LABEL when it should call
+    // ASM_GENERATE_INTERNAL_LABEL, and this causes the leading
+    // underscore to be emitted on some ELF targets).  For ease of use,
+    // we treat such symbols as local.
+    if (name[0] == '_' && name[1] == '.' && name[2] == 'L' && name[3] == '_')
+      return true;
+
+    return false;
+  }
+
  private:
   Target(const Target&);
   Target& operator=(const Target&);
Index: gold/testsuite/Makefile.am
===================================================================
RCS file: /cvs/src/src/gold/testsuite/Makefile.am,v
retrieving revision 1.91
diff -u -u -p -r1.91 Makefile.am
--- gold/testsuite/Makefile.am	26 May 2009 22:52:56 -0000	1.91
+++ gold/testsuite/Makefile.am	5 Jun 2009 01:42:09 -0000
@@ -1074,5 +1074,17 @@ alt/libexclude_libs_test_3.a: exclude_li
 	test -d alt || mkdir -p alt
 	$(TEST_AR) rc $@ $^
 
+check_PROGRAMS += discard_locals_test
+check_SCRIPTS += discard_locals_test.sh
+check_DATA += discard_locals_test.syms
+MOSTLYCLEANFILES += discard_locals_test.syms
+discard_locals_test_SOURCES = discard_locals_test.c
+discard_locals_test_LDFLAGS = -Bgcctestdir/ -Wl,--discard-locals
+discard_locals_test.syms: discard_locals_test
+	$(TEST_READELF) -sW $< >$@ 2>/dev/null
+# '-Wa,--keep-locals' is required to preserve the local label used for testing.
+discard_locals_test.o: discard_locals_test.c
+	$(COMPILE) -c -Wa,--keep-locals -o $@ $<
+
 endif GCC
 endif NATIVE_LINKER
Index: gold/testsuite/Makefile.in
===================================================================
RCS file: /cvs/src/src/gold/testsuite/Makefile.in,v
retrieving revision 1.96
diff -u -u -p -r1.96 Makefile.in
--- gold/testsuite/Makefile.in	26 May 2009 22:52:56 -0000	1.96
+++ gold/testsuite/Makefile.in	5 Jun 2009 01:42:09 -0000
@@ -318,12 +318,17 @@ check_PROGRAMS = object_unittest$(EXEEXT
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_test_2.err \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_test_3.err \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_test_4.err
-@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_24 = exclude_libs_test
-@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_25 = exclude_libs_test.sh
-@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_26 = exclude_libs_test.syms
-@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_27 = exclude_libs_test.syms libexclude_libs_test_1.a \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@        libexclude_libs_test_2.a alt/libexclude_libs_test_3.a
-
+@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_24 = exclude_libs_test \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test
+@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_25 = exclude_libs_test.sh \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test.sh
+@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_26 = exclude_libs_test.syms \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test.syms
+@GCC_TRUE@@NATIVE_LINKER_TRUE@am__append_27 = exclude_libs_test.syms \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	libexclude_libs_test_1.a \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	libexclude_libs_test_2.a \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	alt/libexclude_libs_test_3.a \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test.syms
 subdir = testsuite
 DIST_COMMON = $(srcdir)/Makefile.am $(srcdir)/Makefile.in
 ACLOCAL_M4 = $(top_srcdir)/aclocal.m4
@@ -429,7 +434,8 @@ libgoldtest_a_OBJECTS = $(am_libgoldtest
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_test_3$(EXEEXT) \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@@PLUGINS_TRUE@	plugin_test_4$(EXEEXT)
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am__EXEEXT_17 =  \
-@GCC_TRUE@@NATIVE_LINKER_TRUE@	exclude_libs_test$(EXEEXT)
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	exclude_libs_test$(EXEEXT) \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test$(EXEEXT)
 basic_pic_test_SOURCES = basic_pic_test.c
 basic_pic_test_OBJECTS = basic_pic_test.$(OBJEXT)
 basic_pic_test_LDADD = $(LDADD)
@@ -488,6 +494,14 @@ am__copy_test_SOURCES_DIST = copy_test.c
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am_copy_test_OBJECTS =  \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	copy_test.$(OBJEXT)
 copy_test_OBJECTS = $(am_copy_test_OBJECTS)
+am__discard_locals_test_SOURCES_DIST = discard_locals_test.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@am_discard_locals_test_OBJECTS =  \
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	discard_locals_test.$(OBJEXT)
+discard_locals_test_OBJECTS = $(am_discard_locals_test_OBJECTS)
+discard_locals_test_LDADD = $(LDADD)
+discard_locals_test_DEPENDENCIES = libgoldtest.a ../libgold.a \
+	../../libiberty/libiberty.a $(am__DEPENDENCIES_1) \
+	$(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1)
 am__exception_same_shared_test_SOURCES_DIST = exception_test_main.cc
 @GCC_TRUE@@NATIVE_LINKER_TRUE@am_exception_same_shared_test_OBJECTS =  \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	exception_test_main.$(OBJEXT)
@@ -891,6 +905,7 @@ SOURCES = $(libgoldtest_a_SOURCES) basic
 	$(binary_test_SOURCES) $(binary_unittest_SOURCES) \
 	$(common_test_1_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) \
@@ -944,6 +959,7 @@ DIST_SOURCES = $(libgoldtest_a_SOURCES) 
 	$(am__constructor_static_test_SOURCES_DIST) \
 	$(am__constructor_test_SOURCES_DIST) \
 	$(am__copy_test_SOURCES_DIST) \
+	$(am__discard_locals_test_SOURCES_DIST) \
 	$(am__exception_same_shared_test_SOURCES_DIST) \
 	$(am__exception_separate_shared_12_test_SOURCES_DIST) \
 	$(am__exception_separate_shared_21_test_SOURCES_DIST) \
@@ -1519,6 +1535,8 @@ binary_unittest_SOURCES = binary_unittes
 @GCC_TRUE@@NATIVE_LINKER_TRUE@exclude_libs_test_LDADD = -lexclude_libs_test_1 -lexclude_libs_test_2 \
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	alt/libexclude_libs_test_3.a
 
+@GCC_TRUE@@NATIVE_LINKER_TRUE@discard_locals_test_SOURCES = discard_locals_test.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@discard_locals_test_LDFLAGS = -Bgcctestdir/ -Wl,--discard-locals
 all: $(BUILT_SOURCES)
 	$(MAKE) $(AM_MAKEFLAGS) all-am
 
@@ -1605,6 +1623,9 @@ constructor_test$(EXEEXT): $(constructor
 copy_test$(EXEEXT): $(copy_test_OBJECTS) $(copy_test_DEPENDENCIES) 
 	@rm -f copy_test$(EXEEXT)
 	$(CXXLINK) $(copy_test_LDFLAGS) $(copy_test_OBJECTS) $(copy_test_LDADD) $(LIBS)
+discard_locals_test$(EXEEXT): $(discard_locals_test_OBJECTS) $(discard_locals_test_DEPENDENCIES) 
+	@rm -f discard_locals_test$(EXEEXT)
+	$(LINK) $(discard_locals_test_LDFLAGS) $(discard_locals_test_OBJECTS) $(discard_locals_test_LDADD) $(LIBS)
 exception_same_shared_test$(EXEEXT): $(exception_same_shared_test_OBJECTS) $(exception_same_shared_test_DEPENDENCIES) 
 	@rm -f exception_same_shared_test$(EXEEXT)
 	$(CXXLINK) $(exception_same_shared_test_LDFLAGS) $(exception_same_shared_test_OBJECTS) $(exception_same_shared_test_LDADD) $(LIBS)
@@ -1882,6 +1903,7 @@ distclean-compile:
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/common_test_1.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/constructor_test.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/copy_test.Po@am__quote@
+@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/discard_locals_test.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/exception_test_1.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/exception_test_2.Po@am__quote@
 @AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/exception_test_main.Po@am__quote@
@@ -2613,6 +2635,11 @@ uninstall-am: uninstall-info-am
 @GCC_TRUE@@NATIVE_LINKER_TRUE@alt/libexclude_libs_test_3.a: exclude_libs_test_3.o
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	test -d alt || mkdir -p alt
 @GCC_TRUE@@NATIVE_LINKER_TRUE@	$(TEST_AR) rc $@ $^
+@GCC_TRUE@@NATIVE_LINKER_TRUE@discard_locals_test.syms: discard_locals_test
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(TEST_READELF) -sW $< >$@ 2>/dev/null
+# '-Wa,--keep-locals' is required to preserve the local label used for testing.
+@GCC_TRUE@@NATIVE_LINKER_TRUE@discard_locals_test.o: discard_locals_test.c
+@GCC_TRUE@@NATIVE_LINKER_TRUE@	$(COMPILE) -c -Wa,--keep-locals -o $@ $<
 # Tell versions [3.59,3.63) of GNU make to not export all variables.
 # Otherwise a system limit (for SysV at least) may be exceeded.
 .NOEXPORT:
Index: gold/testsuite/discard_locals_test.c
===================================================================
RCS file: gold/testsuite/discard_locals_test.c
diff -N gold/testsuite/discard_locals_test.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ gold/testsuite/discard_locals_test.c	5 Jun 2009 01:42:09 -0000
@@ -0,0 +1,40 @@
+/* discard_locals_test.c -- test --discard-locals option.
+
+   Copyright 2009 Free Software Foundation, Inc.
+   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 is a test of a common symbol in the main program and a
+   versioned symbol in a shared library.  The common symbol in the
+   main program should override the shared library symbol.  */
+
+int
+main (void)
+{
+  /* local symbol format for generic ELF target. */
+  asm (".Lshould_be_discarded:");
+
+#ifdef __i386__
+  /* additional local symbol format for the i386 target. */
+  asm (".Xshould_be_discarded:");
+#endif
+
+  return 0;
+}
+
Index: gold/testsuite/discard_locals_test.sh
===================================================================
RCS file: gold/testsuite/discard_locals_test.sh
diff -N gold/testsuite/discard_locals_test.sh
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ gold/testsuite/discard_locals_test.sh	5 Jun 2009 01:42:09 -0000
@@ -0,0 +1,44 @@
+#!/bin/sh
+
+# discard_locals_test.sh -- test that local symbols are discarded.
+
+# Copyright 2009 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 file goes with exclude_libs_test.c, a C source file
+# linked with option -Wl,--exclude-libs. We run readelf on
+# the resulting executable and check that symbols from two test library
+# archives are correctly hidden or left unmodified.
+
+check()
+{
+    file=$1
+
+    found=`egrep "should_be_discarded" $file`
+    if test -n "$found"; then
+	echo "These local symbols are not discarded in $file:"
+	echo "$found"
+	exit 1
+    fi
+}
+
+check "discard_locals_test.syms"
+
+exit 0