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Fix --dynamic-list so that symbols not in the list are still exported.

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In PR 13577, the complaint was that -Bsymbolic was overriding the binding
behavior for symbols listed in the --dynamic-list by setting the DT_SYMBOLIC
tag in the dynamic table. In reading the Gnu ld manual, I decided that
--dynamic-list should be mutually exclusive of -Bsymbolic, and modified
gold so that --dynamic-list would treat symbols listed as preemptible,
and all other symbols as internally bound. I was wrong.

PR 16992 shows that with --dynamic-list (and not -Bsymbolic), a symbol
not listed in the dynamic list is being internally bound within the
shared library, but because it's still in the dynamic symbol table, we
expose it to a COPY relocation, and things go really bad from there.

(I can reproduce the same failure, simply by turning on -Bsymbolic-functions
with the Gnu linker. Even though the symbol is bound internally, it's
still exported to the dynamic symbol table, and is exposed to a COPY
relocation.)

I've backed out part of the fix for PR 13577, and -Bsymbolic (or
-Bsymbolic-functions) can now be used with --dynamic-list, but if the
two are used together, we do not set DT_SYMBOLIC or DF_SYMBOLIC
(this matches Gnu ld behavior). We now treat symbols listed in the
dynamic list as premptible, but we do not automatically treat symbols
not listed there as non-premptible.

gold/
	PR gold/13577
	PR gold/16992
	* layout.cc (Layout::finish_dynamic_section): Don't set DT_SYMBOLIC or
	DF_SYMBOLIC if --dynamic-list option is used.
	* options.cc (General_options::finalize): --dynamic-list is not
	mutually exclusive with -Bsymbolic.
	* symtab.h (Symbol::is_preemptible): Don't exclude dynamic symbols not
	listed in --dynamic-list.
	* testsuite/Makefile.am (dynamic_list_lib2.so): Add
	-Bsymbolic-functions.
	* testsuite/Makefile.in: Regenerate.
This commit is contained in:
Cary Coutant 2015-02-16 22:15:12 -08:00
parent 0ed4b0bf3d
commit e9c1bdad26
6 changed files with 20 additions and 14 deletions
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14
gold/ChangeLog
View File

@ -1,3 +1,17 @@
2015-02-16 Cary Coutant <ccoutant@google.com>
PR gold/13577
PR gold/16992
* layout.cc (Layout::finish_dynamic_section): Don't set DT_SYMBOLIC or
DF_SYMBOLIC if --dynamic-list option is used.
* options.cc (General_options::finalize): --dynamic-list is not
mutually exclusive with -Bsymbolic.
* symtab.h (Symbol::is_preemptible): Don't exclude dynamic symbols not
listed in --dynamic-list.
* testsuite/Makefile.am (dynamic_list_lib2.so): Add
-Bsymbolic-functions.
* testsuite/Makefile.in: Regenerate.
2015-02-16 Cary Coutant <ccoutant@google.com>
PR gold/17971

3
gold/layout.cc
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@ -4873,7 +4873,8 @@ Layout::finish_dynamic_section(const Input_objects* input_objects,
flags |= elfcpp::DF_STATIC_TLS;
if (parameters->options().origin())
flags |= elfcpp::DF_ORIGIN;
if (parameters->options().Bsymbolic())
if (parameters->options().Bsymbolic()
&& !parameters->options().have_dynamic_list())
{
flags |= elfcpp::DF_SYMBOLIC;
// Add DT_SYMBOLIC for compatibility with older loaders.

7
gold/options.cc
View File

@ -1200,13 +1200,6 @@ General_options::finalize()
// in the path, as appropriate.
this->add_sysroot();
// --dynamic-list overrides -Bsymbolic and -Bsymbolic-functions.
if (this->have_dynamic_list())
{
this->set_Bsymbolic(false);
this->set_Bsymbolic_functions(false);
}
// Now that we've normalized the options, check for contradictory ones.
if (this->shared() && this->is_static())
gold_fatal(_("-shared and -static are incompatible"));

6
gold/symtab.h
View File

@ -604,10 +604,8 @@ class Symbol
if (parameters->options().in_dynamic_list(this->name()))
return true;
// If the user used -Bsymbolic or provided a --dynamic-list script,
// then nothing (else) is preemptible.
if (parameters->options().Bsymbolic()
|| parameters->options().have_dynamic_list())
// If the user used -Bsymbolic, then nothing (else) is preemptible.
if (parameters->options().Bsymbolic())
return false;
// If the user used -Bsymbolic-functions, then functions are not

2
gold/testsuite/Makefile.am
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@ -1518,7 +1518,7 @@ dynamic_list_lib1.o: dynamic_list_lib1.cc
$(CXXCOMPILE) -c -fpic -o $@ $<
dynamic_list_lib2.so: gcctestdir/ld dynamic_list_lib2.o $(srcdir)/dynamic_list_2.t
$(CXXLINK) -Bgcctestdir/ -shared -Wl,--dynamic-list,$(srcdir)/dynamic_list_2.t dynamic_list_lib2.o
$(CXXLINK) -Bgcctestdir/ -shared -Wl,-Bsymbolic-functions -Wl,--dynamic-list,$(srcdir)/dynamic_list_2.t dynamic_list_lib2.o
dynamic_list_lib2.o: dynamic_list_lib2.cc
$(CXXCOMPILE) -c -fpic -o $@ $<

2
gold/testsuite/Makefile.in
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@ -5319,7 +5319,7 @@ uninstall-am:
@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXCOMPILE) -c -fpic -o $@ $<
@GCC_TRUE@@NATIVE_LINKER_TRUE@dynamic_list_lib2.so: gcctestdir/ld dynamic_list_lib2.o $(srcdir)/dynamic_list_2.t
@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXLINK) -Bgcctestdir/ -shared -Wl,--dynamic-list,$(srcdir)/dynamic_list_2.t dynamic_list_lib2.o
@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXLINK) -Bgcctestdir/ -shared -Wl,-Bsymbolic-functions -Wl,--dynamic-list,$(srcdir)/dynamic_list_2.t dynamic_list_lib2.o
@GCC_TRUE@@NATIVE_LINKER_TRUE@dynamic_list_lib2.o: dynamic_list_lib2.cc
@GCC_TRUE@@NATIVE_LINKER_TRUE@ $(CXXCOMPILE) -c -fpic -o $@ $<