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Fix failure in exception_static_test.

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Because the __EH_FRAME_BEGIN__ symbol is provided in an empty .eh_frame
section in crtbeginT.o, if crt1.o has a non-empty .eh_frame section,
we place all optimized .eh_frame sections into the output section ahead
of the __EH_FRAME_BEGIN__ symbol, which breaks EH for statically-linked
binaries.

This patch fixes the problem by delaying the attachment of the optimized
.eh_frame sections to the output section until we see the end marker
section (or to the end of pass 1 if we never see an end marker).

gold/
	PR gold/14675
	* ehframe.cc (Eh_frame::add_ehframe_input_section): Change return type;
	return enum indicating whether .eh_frame section is empty, optimizable,
	unrecognized, or an end marker. Adjust explicit instantiations.
	* ehframe.h (Eh_frame::Eh_frame_section_disposition): New enum type.
	(Eh_frame::add_ehframe_input_section): Change return type.
	* gold.cc (queue_middle_tasks): Call Layout::finalize_eh_frame_section.
	* layout.cc (Layout::layout_eh_frame): Don't add optimized sections
	to the .eh_frame output section until we see the end marker.
	(Layout::finalize_eh_frame_section): New.
	* layout.h: (Layout::finalize_eh_frame_section): New.
This commit is contained in:
Cary Coutant
2015-03-09 10:10:29 -07:00
parent 9a9df97001
commit e16631979e
6 changed files with 92 additions and 41 deletions
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82
gold/layout.cc
View File

@@ -1420,15 +1420,21 @@ Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
elfcpp::Elf_Xword orig_flags = os->flags();
if (!parameters->incremental()
&& this->eh_frame_data_->add_ehframe_input_section(object,
symbols,
symbols_size,
symbol_names,
symbol_names_size,
shndx,
reloc_shndx,
reloc_type))
Eh_frame::Eh_frame_section_disposition disp =
Eh_frame::EH_UNRECOGNIZED_SECTION;
if (!parameters->incremental())
{
disp = this->eh_frame_data_->add_ehframe_input_section(object,
symbols,
symbols_size,
symbol_names,
symbol_names_size,
shndx,
reloc_shndx,
reloc_type);
}
if (disp == Eh_frame::EH_OPTIMIZABLE_SECTION)
{
os->update_flags_for_input_section(shdr.get_sh_flags());
@@ -1440,35 +1446,49 @@ Layout::layout_eh_frame(Sized_relobj_file<size, big_endian>* object,
os->set_order(ORDER_RELRO);
}
// We found a .eh_frame section we are going to optimize, so now
// we can add the set of optimized sections to the output
// section. We need to postpone adding this until we've found a
// section we can optimize so that the .eh_frame section in
// crtbegin.o winds up at the start of the output section.
if (!this->added_eh_frame_data_)
{
os->add_output_section_data(this->eh_frame_data_);
this->added_eh_frame_data_ = true;
}
*off = -1;
return os;
}
else
{
// We couldn't handle this .eh_frame section for some reason.
// Add it as a normal section.
bool saw_sections_clause = this->script_options_->saw_sections_clause();
*off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
reloc_shndx, saw_sections_clause);
this->have_added_input_section_ = true;
if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
!= (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
os->set_order(this->default_section_order(os, false));
}
if (disp == Eh_frame::EH_END_MARKER_SECTION && !this->added_eh_frame_data_)
{
// We found the end marker section, so now we can add the set of
// optimized sections to the output section. We need to postpone
// adding this until we've found a section we can optimize so that
// the .eh_frame section in crtbeginT.o winds up at the start of
// the output section.
os->add_output_section_data(this->eh_frame_data_);
this->added_eh_frame_data_ = true;
}
// We couldn't handle this .eh_frame section for some reason.
// Add it as a normal section.
bool saw_sections_clause = this->script_options_->saw_sections_clause();
*off = os->add_input_section(this, object, shndx, ".eh_frame", shdr,
reloc_shndx, saw_sections_clause);
this->have_added_input_section_ = true;
if ((orig_flags & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR))
!= (os->flags() & (elfcpp::SHF_WRITE | elfcpp::SHF_EXECINSTR)))
os->set_order(this->default_section_order(os, false));
return os;
}
void
Layout::finalize_eh_frame_section()
{
// If we never found an end marker section, we need to add the
// optimized eh sections to the output section now.
if (!parameters->incremental()
&& this->eh_frame_section_ != NULL
&& !this->added_eh_frame_data_)
{
this->eh_frame_section_->add_output_section_data(this->eh_frame_data_);
this->added_eh_frame_data_ = true;
}
}
// Create and return the magic .eh_frame section. Create
// .eh_frame_hdr also if appropriate. OBJECT is the object with the
// input .eh_frame section; it may be NULL.