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Fix corrupted .eh_frame section with LTO and --gc-sections.

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When --gc-sections is turned on during an LTO link, the .eh_frame sections
from deferred files are processed before those from the replacement files.
As a result, the section end-cap from crtendS.o is placed ahead of
the .eh_frame data from the replacement files. This patch fixes the bug
by skipping the layout of the deferred sections during GC pass 2.

gold/
	PR gold/17639
	* object.cc (Sized_relobj_file): Initialize is_deferred_layout_.
	(Sized_relobj_file::do_layout): Handle deferred sections properly
	during GC pass 1. Don't add reloc sections to deferred list twice.
	* object.h (Sized_relobj_file::is_deferred_layout): New function.
	(Sized_relobj_file::is_deferred_layout_): New data member.
This commit is contained in:
Cary Coutant 2014-11-25 13:55:42 -08:00
parent 61e6682207
commit c924eb67e1
3 changed files with 30 additions and 6 deletions
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9
gold/ChangeLog
View file

@ -1,3 +1,12 @@
2014-11-25 Cary Coutant <ccoutant@google.com>
PR gold/17639
* object.cc (Sized_relobj_file): Initialize is_deferred_layout_.
(Sized_relobj_file::do_layout): Handle deferred sections properly
during GC pass 1. Don't add reloc sections to deferred list twice.
* object.h (Sized_relobj_file::is_deferred_layout): New function.
(Sized_relobj_file::is_deferred_layout_): New data member.
2014-11-21 H.J. Lu <hongjiu.lu@intel.com> 2014-11-21 H.J. Lu <hongjiu.lu@intel.com>
PR gold/17619 PR gold/17619

18
gold/object.cc
View file

@ -430,6 +430,7 @@ Sized_relobj_file<size, big_endian>::Sized_relobj_file(
kept_comdat_sections_(), kept_comdat_sections_(),
has_eh_frame_(false), has_eh_frame_(false),
discarded_eh_frame_shndx_(-1U), discarded_eh_frame_shndx_(-1U),
is_deferred_layout_(false),
deferred_layout_(), deferred_layout_(),
deferred_layout_relocs_(), deferred_layout_relocs_(),
compressed_sections_() compressed_sections_()
@ -1430,6 +1431,7 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
{ {
parameters->options().plugins()->add_deferred_layout_object(this); parameters->options().plugins()->add_deferred_layout_object(this);
this->deferred_layout_.reserve(num_sections_to_defer); this->deferred_layout_.reserve(num_sections_to_defer);
this->is_deferred_layout_ = true;
} }
// Whether we've seen a .note.GNU-stack section. // Whether we've seen a .note.GNU-stack section.
@ -1590,10 +1592,13 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
{ {
if (is_pass_one) if (is_pass_one)
{ {
if (this->is_deferred_layout())
out_sections[i] = reinterpret_cast<Output_section*>(2);
else
out_sections[i] = reinterpret_cast<Output_section*>(1); out_sections[i] = reinterpret_cast<Output_section*>(1);
out_section_offsets[i] = invalid_address; out_section_offsets[i] = invalid_address;
} }
else if (should_defer_layout) else if (this->is_deferred_layout())
this->deferred_layout_.push_back(Deferred_layout(i, name, this->deferred_layout_.push_back(Deferred_layout(i, name,
pshdrs, pshdrs,
reloc_shndx[i], reloc_shndx[i],
@ -1658,11 +1663,12 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
} }
// Defer layout here if input files are claimed by plugins. When gc // Defer layout here if input files are claimed by plugins. When gc
// is turned on this function is called twice. For the second call // is turned on this function is called twice; we only want to do this
// should_defer_layout should be false. // on the first pass.
if (should_defer_layout && (shdr.get_sh_flags() & elfcpp::SHF_ALLOC)) if (!is_pass_two
&& this->is_deferred_layout()
&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC))
{ {
gold_assert(!is_pass_two);
this->deferred_layout_.push_back(Deferred_layout(i, name, this->deferred_layout_.push_back(Deferred_layout(i, name,
pshdrs, pshdrs,
reloc_shndx[i], reloc_shndx[i],
@ -1764,6 +1770,8 @@ Sized_relobj_file<size, big_endian>::do_layout(Symbol_table* symtab,
Output_section* data_section = out_sections[data_shndx]; Output_section* data_section = out_sections[data_shndx];
if (data_section == reinterpret_cast<Output_section*>(2)) if (data_section == reinterpret_cast<Output_section*>(2))
{ {
if (is_pass_two)
continue;
// The layout for the data section was deferred, so we need // The layout for the data section was deferred, so we need
// to defer the relocation section, too. // to defer the relocation section, too.
const char* name = pnames + shdr.get_sh_name(); const char* name = pnames + shdr.get_sh_name();

7
gold/object.h
View file

@ -2202,6 +2202,10 @@ class Sized_relobj_file : public Sized_relobj<size, big_endian>
Symbol_value<size>* lv_out, Symbol_value<size>* lv_out,
const Symbol_table* symtab); const Symbol_table* symtab);
// Return true if the layout for this object was deferred.
bool is_deferred_layout() const
{ return this->is_deferred_layout_; }
protected: protected:
typedef typename Sized_relobj<size, big_endian>::Output_sections typedef typename Sized_relobj<size, big_endian>::Output_sections
Output_sections; Output_sections;
@ -2740,6 +2744,9 @@ class Sized_relobj_file : public Sized_relobj<size, big_endian>
// If this object has a GNU style .eh_frame section that is discarded in // If this object has a GNU style .eh_frame section that is discarded in
// output, record the index here. Otherwise it is -1U. // output, record the index here. Otherwise it is -1U.
unsigned int discarded_eh_frame_shndx_; unsigned int discarded_eh_frame_shndx_;
// True if the layout of this object was deferred, waiting for plugin
// replacement files.
bool is_deferred_layout_;
// The list of sections whose layout was deferred. // The list of sections whose layout was deferred.
std::vector<Deferred_layout> deferred_layout_; std::vector<Deferred_layout> deferred_layout_;
// The list of relocation sections whose layout was deferred. // The list of relocation sections whose layout was deferred.