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Add option --weak-unresolved-symbols to treat unresolved symbols as weak ref.

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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.
This commit is contained in:
Sriraman Tallam 2015-04-23 13:56:40 -07:00
parent 65eb8c79be
commit a100d66fb4
6 changed files with 69 additions and 5 deletions
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10
gold/ChangeLog
View File

@ -1,3 +1,13 @@
2015-04-23 Sriraman Tallam <tmsriram@google.com>
* 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.
2015-04-20 Ian Coolidge <icoolidge@google.com>
* symtab.cc (Symbol::should_add_dynsym_entry): Return true for

3
gold/options.h
View File

@ -1219,6 +1219,9 @@ class General_options
options::TWO_DASHES, '\0',
N_("Report unresolved symbols as errors"),
NULL, true);
DEFINE_bool(weak_unresolved_symbols, options::TWO_DASHES, '\0', false,
N_("Convert unresolved symbols to weak references"),
NULL);
DEFINE_bool(wchar_size_warning, options::TWO_DASHES, '\0', true, NULL,
N_("(ARM only) Do not warn about objects with incompatible "

7
gold/symtab.cc
View File

@ -2920,6 +2920,13 @@ Symbol_table::sized_write_globals(const Stringpool* sympool,
typename elfcpp::Elf_types<size>::Elf_Addr dynsym_value = sym_value;
elfcpp::STB binding = sym->binding();
// If --weak-unresolved-symbols is set, change binding of unresolved
// global symbols to STB_WEAK.
if (parameters->options().weak_unresolved_symbols()
&& binding == elfcpp::STB_GLOBAL
&& sym->is_undefined())
binding = elfcpp::STB_WEAK;
// If --no-gnu-unique is set, change STB_GNU_UNIQUE to STB_GLOBAL.
if (binding == elfcpp::STB_GNU_UNIQUE
&& !parameters->options().gnu_unique())

6
gold/symtab.h
View File

@ -526,7 +526,8 @@ class Symbol
{
return (this->is_undefined()
&& (this->binding() == elfcpp::STB_WEAK
|| this->is_undef_binding_weak()));
|| this->is_undef_binding_weak()
|| parameters->options().weak_unresolved_symbols()));
}
// Return whether this is a strong undefined symbol.
@ -535,7 +536,8 @@ class Symbol
{
return (this->is_undefined()
&& this->binding() != elfcpp::STB_WEAK
&& !this->is_undef_binding_weak());
&& !this->is_undef_binding_weak()
&& !parameters->options().weak_unresolved_symbols());
}
// Return whether this is an absolute symbol.

5
gold/testsuite/Makefile.am
View File

@ -533,6 +533,11 @@ pie_copyrelocs_shared_test.o: pie_copyrelocs_shared_test.cc
pie_copyrelocs_shared_test.so: pie_copyrelocs_shared_test.o gcctestdir/ld
$(CXXLINK) -Bgcctestdir/ -shared pie_copyrelocs_shared_test.o
check_PROGRAMS += weak_unresolved_symbols_test
weak_unresolved_symbols_test_SOURCES = weak_unresolved_symbols_test.cc
weak_unresolved_symbols_test_CXXFLAGS = -fPIE
weak_unresolved_symbols_test_LDFLAGS = -Bgcctestdir/ -pie -Wl,--weak-unresolved-symbols
check_SCRIPTS += two_file_shared.sh
check_DATA += two_file_shared.dbg
MOSTLYCLEANFILES += two_file_shared.dbg

43
gold/testsuite/Makefile.in
View File

@ -147,7 +147,8 @@ check_PROGRAMS = $(am__EXEEXT_1) $(am__EXEEXT_2) $(am__EXEEXT_3) \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_separate_shared_21_test \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_relocatable_test \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_pie_test \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ pie_copyrelocs_test
@GCC_TRUE@@NATIVE_LINKER_TRUE@ pie_copyrelocs_test \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ weak_unresolved_symbols_test
# The nonpic tests will fail on platforms which can not put non-PIC
# code into shared libraries, so we just don't run them in that case.
@ -842,7 +843,8 @@ libgoldtest_a_OBJECTS = $(am_libgoldtest_a_OBJECTS)
@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_separate_shared_21_test$(EXEEXT) \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_relocatable_test$(EXEEXT) \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_pie_test$(EXEEXT) \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ pie_copyrelocs_test$(EXEEXT)
@GCC_TRUE@@NATIVE_LINKER_TRUE@ pie_copyrelocs_test$(EXEEXT) \
@GCC_TRUE@@NATIVE_LINKER_TRUE@ weak_unresolved_symbols_test$(EXEEXT)
@FN_PTRS_IN_SO_WITHOUT_PIC_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@am__EXEEXT_9 = two_file_shared_1_nonpic_test$(EXEEXT) \
@FN_PTRS_IN_SO_WITHOUT_PIC_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_shared_2_nonpic_test$(EXEEXT) \
@FN_PTRS_IN_SO_WITHOUT_PIC_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_same_shared_nonpic_test$(EXEEXT) \
@ -1966,6 +1968,17 @@ weak_undef_test_LINK = $(CXXLD) $(AM_CXXFLAGS) $(CXXFLAGS) \
weak_undef_test_2_OBJECTS = $(am_weak_undef_test_2_OBJECTS)
weak_undef_test_2_LINK = $(CXXLD) $(AM_CXXFLAGS) $(CXXFLAGS) \
$(weak_undef_test_2_LDFLAGS) $(LDFLAGS) -o $@
@GCC_TRUE@@NATIVE_LINKER_TRUE@am_weak_unresolved_symbols_test_OBJECTS = weak_unresolved_symbols_test-weak_unresolved_symbols_test.$(OBJEXT)
weak_unresolved_symbols_test_OBJECTS = \
$(am_weak_unresolved_symbols_test_OBJECTS)
weak_unresolved_symbols_test_LDADD = $(LDADD)
weak_unresolved_symbols_test_DEPENDENCIES = libgoldtest.a ../libgold.a \
../../libiberty/libiberty.a $(am__DEPENDENCIES_1) \
$(am__DEPENDENCIES_1) $(am__DEPENDENCIES_1) \
$(am__DEPENDENCIES_1)
weak_unresolved_symbols_test_LINK = $(CXXLD) \
$(weak_unresolved_symbols_test_CXXFLAGS) $(CXXFLAGS) \
$(weak_unresolved_symbols_test_LDFLAGS) $(LDFLAGS) -o $@
DEFAULT_INCLUDES = -I.@am__isrc@ -I$(top_builddir)
depcomp = $(SHELL) $(top_srcdir)/../depcomp
am__depfiles_maybe = depfiles
@ -2057,7 +2070,8 @@ SOURCES = $(libgoldtest_a_SOURCES) basic_pic_test.c basic_pie_test.c \
$(ver_test_8_SOURCES) $(ver_test_9_SOURCES) \
$(weak_alias_test_SOURCES) weak_plt.c $(weak_test_SOURCES) \
$(weak_undef_nonpic_test_SOURCES) $(weak_undef_test_SOURCES) \
$(weak_undef_test_2_SOURCES)
$(weak_undef_test_2_SOURCES) \
$(weak_unresolved_symbols_test_SOURCES)
ETAGS = etags
CTAGS = ctags
am__tty_colors = \
@ -2465,6 +2479,9 @@ LDADD = libgoldtest.a ../libgold.a ../../libiberty/libiberty.a $(LIBINTL) \
@GCC_TRUE@@NATIVE_LINKER_TRUE@pie_copyrelocs_test_CXXFLAGS = -fno-exceptions -fno-asynchronous-unwind-tables
@GCC_TRUE@@NATIVE_LINKER_TRUE@pie_copyrelocs_test_LDFLAGS = -Bgcctestdir/ -Wl,-R,. -pie
@GCC_TRUE@@NATIVE_LINKER_TRUE@pie_copyrelocs_test_LDADD = pie_copyrelocs_shared_test.so
@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_unresolved_symbols_test_SOURCES = weak_unresolved_symbols_test.cc
@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_unresolved_symbols_test_CXXFLAGS = -fPIE
@GCC_TRUE@@NATIVE_LINKER_TRUE@weak_unresolved_symbols_test_LDFLAGS = -Bgcctestdir/ -pie -Wl,--weak-unresolved-symbols
@FN_PTRS_IN_SO_WITHOUT_PIC_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@two_file_shared_1_nonpic_test_SOURCES = \
@FN_PTRS_IN_SO_WITHOUT_PIC_TRUE@@GCC_TRUE@@NATIVE_LINKER_TRUE@ two_file_test_2.cc two_file_test_main.cc
@ -3722,6 +3739,9 @@ weak_undef_test$(EXEEXT): $(weak_undef_test_OBJECTS) $(weak_undef_test_DEPENDENC
weak_undef_test_2$(EXEEXT): $(weak_undef_test_2_OBJECTS) $(weak_undef_test_2_DEPENDENCIES)
@rm -f weak_undef_test_2$(EXEEXT)
$(weak_undef_test_2_LINK) $(weak_undef_test_2_OBJECTS) $(weak_undef_test_2_LDADD) $(LIBS)
weak_unresolved_symbols_test$(EXEEXT): $(weak_unresolved_symbols_test_OBJECTS) $(weak_unresolved_symbols_test_DEPENDENCIES)
@rm -f weak_unresolved_symbols_test$(EXEEXT)
$(weak_unresolved_symbols_test_LINK) $(weak_unresolved_symbols_test_OBJECTS) $(weak_unresolved_symbols_test_LDADD) $(LIBS)
mostlyclean-compile:
-rm -f *.$(OBJEXT)
@ -3852,6 +3872,7 @@ distclean-compile:
@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@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/weak_undef_test_2.Po@am__quote@
@AMDEP_TRUE@@am__include@ @am__quote@./$(DEPDIR)/weak_unresolved_symbols_test-weak_unresolved_symbols_test.Po@am__quote@
.c.o:
@am__fastdepCC_TRUE@ $(COMPILE) -MT $@ -MD -MP -MF $(DEPDIR)/$*.Tpo -c -o $@ $<
@ -3979,6 +4000,20 @@ pie_copyrelocs_test-pie_copyrelocs_test.obj: pie_copyrelocs_test.cc
@AMDEP_TRUE@@am__fastdepCXX_FALSE@ DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
@am__fastdepCXX_FALSE@ $(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(pie_copyrelocs_test_CXXFLAGS) $(CXXFLAGS) -c -o pie_copyrelocs_test-pie_copyrelocs_test.obj `if test -f 'pie_copyrelocs_test.cc'; then $(CYGPATH_W) 'pie_copyrelocs_test.cc'; else $(CYGPATH_W) '$(srcdir)/pie_copyrelocs_test.cc'; fi`
weak_unresolved_symbols_test-weak_unresolved_symbols_test.o: weak_unresolved_symbols_test.cc
@am__fastdepCXX_TRUE@ $(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(weak_unresolved_symbols_test_CXXFLAGS) $(CXXFLAGS) -MT weak_unresolved_symbols_test-weak_unresolved_symbols_test.o -MD -MP -MF $(DEPDIR)/weak_unresolved_symbols_test-weak_unresolved_symbols_test.Tpo -c -o weak_unresolved_symbols_test-weak_unresolved_symbols_test.o `test -f 'weak_unresolved_symbols_test.cc' || echo '$(srcdir)/'`weak_unresolved_symbols_test.cc
@am__fastdepCXX_TRUE@ $(am__mv) $(DEPDIR)/weak_unresolved_symbols_test-weak_unresolved_symbols_test.Tpo $(DEPDIR)/weak_unresolved_symbols_test-weak_unresolved_symbols_test.Po
@AMDEP_TRUE@@am__fastdepCXX_FALSE@ source='weak_unresolved_symbols_test.cc' object='weak_unresolved_symbols_test-weak_unresolved_symbols_test.o' libtool=no @AMDEPBACKSLASH@
@AMDEP_TRUE@@am__fastdepCXX_FALSE@ DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
@am__fastdepCXX_FALSE@ $(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(weak_unresolved_symbols_test_CXXFLAGS) $(CXXFLAGS) -c -o weak_unresolved_symbols_test-weak_unresolved_symbols_test.o `test -f 'weak_unresolved_symbols_test.cc' || echo '$(srcdir)/'`weak_unresolved_symbols_test.cc
weak_unresolved_symbols_test-weak_unresolved_symbols_test.obj: weak_unresolved_symbols_test.cc
@am__fastdepCXX_TRUE@ $(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(weak_unresolved_symbols_test_CXXFLAGS) $(CXXFLAGS) -MT weak_unresolved_symbols_test-weak_unresolved_symbols_test.obj -MD -MP -MF $(DEPDIR)/weak_unresolved_symbols_test-weak_unresolved_symbols_test.Tpo -c -o weak_unresolved_symbols_test-weak_unresolved_symbols_test.obj `if test -f 'weak_unresolved_symbols_test.cc'; then $(CYGPATH_W) 'weak_unresolved_symbols_test.cc'; else $(CYGPATH_W) '$(srcdir)/weak_unresolved_symbols_test.cc'; fi`
@am__fastdepCXX_TRUE@ $(am__mv) $(DEPDIR)/weak_unresolved_symbols_test-weak_unresolved_symbols_test.Tpo $(DEPDIR)/weak_unresolved_symbols_test-weak_unresolved_symbols_test.Po
@AMDEP_TRUE@@am__fastdepCXX_FALSE@ source='weak_unresolved_symbols_test.cc' object='weak_unresolved_symbols_test-weak_unresolved_symbols_test.obj' libtool=no @AMDEPBACKSLASH@
@AMDEP_TRUE@@am__fastdepCXX_FALSE@ DEPDIR=$(DEPDIR) $(CXXDEPMODE) $(depcomp) @AMDEPBACKSLASH@
@am__fastdepCXX_FALSE@ $(CXX) $(DEFS) $(DEFAULT_INCLUDES) $(INCLUDES) $(AM_CPPFLAGS) $(CPPFLAGS) $(weak_unresolved_symbols_test_CXXFLAGS) $(CXXFLAGS) -c -o weak_unresolved_symbols_test-weak_unresolved_symbols_test.obj `if test -f 'weak_unresolved_symbols_test.cc'; then $(CYGPATH_W) 'weak_unresolved_symbols_test.cc'; else $(CYGPATH_W) '$(srcdir)/weak_unresolved_symbols_test.cc'; fi`
ID: $(HEADERS) $(SOURCES) $(LISP) $(TAGS_FILES)
list='$(SOURCES) $(HEADERS) $(LISP) $(TAGS_FILES)'; \
unique=`for i in $$list; do \
@ -4403,6 +4438,8 @@ two_file_pie_test.log: two_file_pie_test$(EXEEXT)
@p='two_file_pie_test$(EXEEXT)'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
pie_copyrelocs_test.log: pie_copyrelocs_test$(EXEEXT)
@p='pie_copyrelocs_test$(EXEEXT)'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
weak_unresolved_symbols_test.log: weak_unresolved_symbols_test$(EXEEXT)
@p='weak_unresolved_symbols_test$(EXEEXT)'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
two_file_shared_1_nonpic_test.log: two_file_shared_1_nonpic_test$(EXEEXT)
@p='two_file_shared_1_nonpic_test$(EXEEXT)'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
two_file_shared_2_nonpic_test.log: two_file_shared_2_nonpic_test$(EXEEXT)