* compressed_output.cc (zlib_decompress): New function.

(get_uncompressed_size): New function.
	(decompress_input_section): New function.
	* compressed_output.h (get_uncompressed_size): New function.
	(decompress_input_section): New function.
	* dwarf_reader.cc (Sized_dwarf_line_info::Sized_dwarf_line_info)
	Handle compressed debug sections.
	* layout.cc (is_compressed_debug_section): New function.
	(Layout::output_section_name): Map compressed section names to
	canonical names.
	* layout.h (is_compressed_debug_section): New function.
	(is_debug_info_section): Recognize compressed debug sections.
	* merge.cc: Include compressed_output.h.
	(Output_merge_data::do_add_input_section): Handle compressed
	debug sections.
	(Output_merge_string::do_add_input_section): Handle compressed
	debug sections.
	* object.cc: Include compressed_output.h.
	(Sized_relobj::Sized_relobj): Initialize new data members.
	(build_compressed_section_map): New function.
	(Sized_relobj::do_read_symbols): Handle compressed debug sections.
	* object.h (Object::section_is_compressed): New method.
	(Object::do_section_is_compressed): New method.
	(Sized_relobj::Compressed_section_map): New type.
	(Sized_relobj::do_section_is_compressed): New method.
	(Sized_relobj::compressed_sections_): New data member.
	* output.cc (Output_section::add_input_section): Handle compressed
	debug sections.
	* reloc.cc: Include compressed_output.h.
	(Sized_relobj::write_sections): Handle compressed debug sections.
This commit is contained in:
Cary Coutant 2010-07-12 17:59:58 +00:00
parent add265ae41
commit a2e4736229
11 changed files with 358 additions and 17 deletions

View file

@ -1,3 +1,36 @@
2010-07-12 Cary Coutant <ccoutant@google.com>
* compressed_output.cc (zlib_decompress): New function.
(get_uncompressed_size): New function.
(decompress_input_section): New function.
* compressed_output.h (get_uncompressed_size): New function.
(decompress_input_section): New function.
* dwarf_reader.cc (Sized_dwarf_line_info::Sized_dwarf_line_info)
Handle compressed debug sections.
* layout.cc (is_compressed_debug_section): New function.
(Layout::output_section_name): Map compressed section names to
canonical names.
* layout.h (is_compressed_debug_section): New function.
(is_debug_info_section): Recognize compressed debug sections.
* merge.cc: Include compressed_output.h.
(Output_merge_data::do_add_input_section): Handle compressed
debug sections.
(Output_merge_string::do_add_input_section): Handle compressed
debug sections.
* object.cc: Include compressed_output.h.
(Sized_relobj::Sized_relobj): Initialize new data members.
(build_compressed_section_map): New function.
(Sized_relobj::do_read_symbols): Handle compressed debug sections.
* object.h (Object::section_is_compressed): New method.
(Object::do_section_is_compressed): New method.
(Sized_relobj::Compressed_section_map): New type.
(Sized_relobj::do_section_is_compressed): New method.
(Sized_relobj::compressed_sections_): New data member.
* output.cc (Output_section::add_input_section): Handle compressed
debug sections.
* reloc.cc: Include compressed_output.h.
(Sized_relobj::write_sections): Handle compressed debug sections.
2010-07-08 Cary Coutant <ccoutant@google.com>
* resolve.cc (Symbol_table::resolve): Remember whether undef was

View file

@ -1,6 +1,6 @@
// compressed_output.cc -- manage compressed output sections for gold
// compressed_output.cc -- manage compressed debug sections for gold
// Copyright 2007, 2008 Free Software Foundation, Inc.
// Copyright 2007, 2008, 2010 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
@ -33,6 +33,8 @@
namespace gold
{
#ifdef HAVE_ZLIB_H
// Compress UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE. Returns true
// if it successfully compressed, false if it failed for any reason
// (including not having zlib support in the library). If it returns
@ -42,8 +44,6 @@ namespace gold
// "ZLIB", and 8 bytes indicating the uncompressed size, in big-endian
// order.
#ifdef HAVE_ZLIB_H
static bool
zlib_compress(const unsigned char* uncompressed_data,
unsigned long uncompressed_size,
@ -81,6 +81,49 @@ zlib_compress(const unsigned char* uncompressed_data,
}
}
// Decompress COMPRESSED_DATA of size COMPRESSED_SIZE, into a buffer
// UNCOMPRESSED_DATA of size UNCOMPRESSED_SIZE. Returns TRUE if it
// decompressed successfully, false if it failed. The buffer, of
// appropriate size, is provided by the caller, and is typically part
// of the memory-mapped output file.
static bool
zlib_decompress(const unsigned char* compressed_data,
unsigned long compressed_size,
unsigned char* uncompressed_data,
unsigned long uncompressed_size)
{
z_stream strm;
int rc;
/* It is possible the section consists of several compressed
buffers concatenated together, so we uncompress in a loop. */
strm.zalloc = NULL;
strm.zfree = NULL;
strm.opaque = NULL;
strm.avail_in = compressed_size;
strm.next_in = const_cast<Bytef*>(compressed_data);
strm.avail_out = uncompressed_size;
rc = inflateInit(&strm);
while (strm.avail_in > 0)
{
if (rc != Z_OK)
return false;
strm.next_out = ((Bytef*) uncompressed_data
+ (uncompressed_size - strm.avail_out));
rc = inflate(&strm, Z_FINISH);
if (rc != Z_STREAM_END)
return false;
rc = inflateReset(&strm);
}
rc = inflateEnd(&strm);
if (rc != Z_OK || strm.avail_out != 0)
return false;
return true;
}
#else // !defined(HAVE_ZLIB_H)
static bool
@ -90,8 +133,62 @@ zlib_compress(const unsigned char*, unsigned long,
return false;
}
static bool
zlib_decompress(const unsigned char*, unsigned long,
unsigned char**, unsigned long*)
{
return false;
}
#endif // !defined(HAVE_ZLIB_H)
// Read the compression header of a compressed debug section and return
// the uncompressed size.
uint64_t
get_uncompressed_size(const unsigned char* compressed_data,
section_size_type compressed_size)
{
const unsigned int zlib_header_size = 12;
/* Verify the compression header. Currently, we support only zlib
compression, so it should be "ZLIB" followed by the uncompressed
section size, 8 bytes in big-endian order. */
if (compressed_size >= zlib_header_size
&& strncmp(reinterpret_cast<const char*>(compressed_data),
"ZLIB", 4) == 0)
return elfcpp::Swap_unaligned<64, true>::readval(compressed_data + 4);
return -1ULL;
}
// Decompress a compressed debug section directly into the output file.
bool
decompress_input_section(const unsigned char* compressed_data,
unsigned long compressed_size,
unsigned char* uncompressed_data,
unsigned long uncompressed_size)
{
const unsigned int zlib_header_size = 12;
/* Verify the compression header. Currently, we support only zlib
compression, so it should be "ZLIB" followed by the uncompressed
section size, 8 bytes in big-endian order. */
if (compressed_size >= zlib_header_size
&& strncmp(reinterpret_cast<const char*>(compressed_data),
"ZLIB", 4) == 0)
{
unsigned long uncompressed_size_check =
elfcpp::Swap_unaligned<64, true>::readval(compressed_data + 4);
gold_assert(uncompressed_size_check == uncompressed_size);
return zlib_decompress(compressed_data + zlib_header_size,
compressed_size - zlib_header_size,
uncompressed_data,
uncompressed_size);
}
return false;
}
// Class Output_compressed_section.
// Set the final data size of a compressed section. This is where

View file

@ -1,6 +1,6 @@
// compressed_output.h -- compressed output sections for gold -*- C++ -*-
// Copyright 2007, 2008 Free Software Foundation, Inc.
// Copyright 2007, 2008, 2010 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
@ -37,6 +37,18 @@ namespace gold
class General_options;
// Read the compression header of a compressed debug section and return
// the uncompressed size.
extern uint64_t
get_uncompressed_size(const unsigned char*, section_size_type);
// Decompress a compressed debug section directly into the output file.
extern bool
decompress_input_section(const unsigned char*, unsigned long, unsigned char*,
unsigned long);
// This is used for a section whose data should be compressed. It is
// a regular Output_section which computes its contents into a buffer
// and then postprocesses it.

View file

@ -32,6 +32,7 @@
#include "reloc.h"
#include "dwarf_reader.h"
#include "int_encoding.h"
#include "compressed_output.h"
namespace gold {
@ -80,6 +81,21 @@ Sized_dwarf_line_info<size, big_endian>::Sized_dwarf_line_info(Object* object,
if (this->buffer_ == NULL)
return;
section_size_type uncompressed_size = 0;
unsigned char* uncompressed_data = NULL;
if (object->section_is_compressed(debug_shndx, &uncompressed_size))
{
uncompressed_data = new unsigned char[uncompressed_size];
if (!decompress_input_section(this->buffer_,
this->buffer_end_ - this->buffer_,
uncompressed_data,
uncompressed_size))
object->error(_("could not decompress section %s"),
object->section_name(debug_shndx).c_str());
this->buffer_ = uncompressed_data;
this->buffer_end_ = this->buffer_ + uncompressed_size;
}
// Find the relocation section for ".debug_line".
// We expect these for relobjs (.o's) but not dynobjs (.so's).
bool got_relocs = false;

View file

@ -944,7 +944,16 @@ Layout::section_flags_to_segment(elfcpp::Elf_Xword flags)
static bool
is_compressible_debug_section(const char* secname)
{
return (strncmp(secname, ".debug", sizeof(".debug") - 1) == 0);
return (is_prefix_of(".debug", secname));
}
// We may see compressed debug sections in input files. Return TRUE
// if this is the name of a compressed debug section.
bool
is_compressed_debug_section(const char* secname)
{
return (is_prefix_of(".zdebug", secname));
}
// Make a new Output_section, and attach it to segments as
@ -3772,6 +3781,20 @@ Layout::output_section_name(const char* name, size_t* plen)
}
}
// Compressed debug sections should be mapped to the corresponding
// uncompressed section.
if (is_compressed_debug_section(name))
{
size_t len = strlen(name);
char *uncompressed_name = new char[len];
uncompressed_name[0] = '.';
gold_assert(name[0] == '.' && name[1] == 'z');
strncpy(&uncompressed_name[1], &name[2], len - 2);
uncompressed_name[len - 1] = '\0';
*plen = len - 1;
return uncompressed_name;
}
return name;
}

View file

@ -59,6 +59,10 @@ class Output_reduced_debug_info_section;
class Eh_frame;
class Target;
// Return TRUE if SECNAME is the name of a compressed debug section.
extern bool
is_compressed_debug_section(const char* secname);
// This task function handles mapping the input sections to output
// sections and laying them out in memory.
@ -451,6 +455,7 @@ class Layout
{
// Debugging sections can only be recognized by name.
return (strncmp(name, ".debug", sizeof(".debug") - 1) == 0
|| strncmp(name, ".zdebug", sizeof(".zdebug") - 1) == 0
|| strncmp(name, ".gnu.linkonce.wi.",
sizeof(".gnu.linkonce.wi.") - 1) == 0
|| strncmp(name, ".line", sizeof(".line") - 1) == 0

View file

@ -1,6 +1,6 @@
// merge.cc -- handle section merging for gold
// Copyright 2006, 2007, 2008 Free Software Foundation, Inc.
// Copyright 2006, 2007, 2008, 2010 Free Software Foundation, Inc.
// Written by Ian Lance Taylor <iant@google.com>.
// This file is part of gold.
@ -26,6 +26,7 @@
#include <algorithm>
#include "merge.h"
#include "compressed_output.h"
namespace gold
{
@ -404,12 +405,29 @@ bool
Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx)
{
section_size_type len;
section_size_type uncompressed_size = 0;
unsigned char* uncompressed_data = NULL;
const unsigned char* p = object->section_contents(shndx, &len, false);
if (object->section_is_compressed(shndx, &uncompressed_size))
{
uncompressed_data = new unsigned char[uncompressed_size];
if (!decompress_input_section(p, len, uncompressed_data,
uncompressed_size))
object->error(_("could not decompress section %s"),
object->section_name(shndx).c_str());
p = uncompressed_data;
len = uncompressed_size;
}
section_size_type entsize = convert_to_section_size_type(this->entsize());
if (len % entsize != 0)
return false;
{
if (uncompressed_data != NULL)
delete[] uncompressed_data;
return false;
}
this->input_count_ += len / entsize;
@ -438,6 +456,9 @@ Output_merge_data::do_add_input_section(Relobj* object, unsigned int shndx)
if (this->keeps_input_sections())
record_input_section(object, shndx);
if (uncompressed_data != NULL)
delete[] uncompressed_data;
return true;
}
@ -495,8 +516,21 @@ Output_merge_string<Char_type>::do_add_input_section(Relobj* object,
unsigned int shndx)
{
section_size_type len;
section_size_type uncompressed_size = 0;
unsigned char* uncompressed_data = NULL;
const unsigned char* pdata = object->section_contents(shndx, &len, false);
if (object->section_is_compressed(shndx, &uncompressed_size))
{
uncompressed_data = new unsigned char[uncompressed_size];
if (!decompress_input_section(pdata, len, uncompressed_data,
uncompressed_size))
object->error(_("could not decompress section %s"),
object->section_name(shndx).c_str());
pdata = uncompressed_data;
len = uncompressed_size;
}
const Char_type* p = reinterpret_cast<const Char_type*>(pdata);
const Char_type* pend = p + len / sizeof(Char_type);
@ -504,6 +538,8 @@ Output_merge_string<Char_type>::do_add_input_section(Relobj* object,
{
object->error(_("mergeable string section length not multiple of "
"character size"));
if (uncompressed_data != NULL)
delete[] uncompressed_data;
return false;
}
@ -545,6 +581,9 @@ Output_merge_string<Char_type>::do_add_input_section(Relobj* object,
if (this->keeps_input_sections())
record_input_section(object, shndx);
if (uncompressed_data != NULL)
delete[] uncompressed_data;
return true;
}

View file

@ -39,6 +39,7 @@
#include "object.h"
#include "dynobj.h"
#include "plugin.h"
#include "compressed_output.h"
namespace gold
{
@ -367,7 +368,10 @@ Sized_relobj<size, big_endian>::Sized_relobj(
local_got_offsets_(),
kept_comdat_sections_(),
has_eh_frame_(false),
discarded_eh_frame_shndx_(-1U)
discarded_eh_frame_shndx_(-1U),
deferred_layout_(),
deferred_layout_relocs_(),
compressed_sections_()
{
}
@ -495,6 +499,50 @@ Sized_relobj<size, big_endian>::find_eh_frame(
return false;
}
// Build a table for any compressed debug sections, mapping each section index
// to the uncompressed size.
template<int size, bool big_endian>
Compressed_section_map*
build_compressed_section_map(
const unsigned char* pshdrs,
unsigned int shnum,
const char* names,
section_size_type names_size,
Sized_relobj<size, big_endian>* obj)
{
Compressed_section_map* uncompressed_sizes = new Compressed_section_map();
const unsigned int shdr_size = elfcpp::Elf_sizes<size>::shdr_size;
const unsigned char* p = pshdrs + shdr_size;
for (unsigned int i = 1; i < shnum; ++i, p += shdr_size)
{
typename elfcpp::Shdr<size, big_endian> shdr(p);
if (shdr.get_sh_type() == elfcpp::SHT_PROGBITS
&& (shdr.get_sh_flags() & elfcpp::SHF_ALLOC) == 0)
{
if (shdr.get_sh_name() >= names_size)
{
obj->error(_("bad section name offset for section %u: %lu"),
i, static_cast<unsigned long>(shdr.get_sh_name()));
continue;
}
const char* name = names + shdr.get_sh_name();
if (is_compressed_debug_section(name))
{
section_size_type len;
const unsigned char* contents =
obj->section_contents(i, &len, false);
uint64_t uncompressed_size = get_uncompressed_size(contents, len);
if (uncompressed_size != -1ULL)
(*uncompressed_sizes)[i] =
convert_to_section_size_type(uncompressed_size);
}
}
}
return uncompressed_sizes;
}
// Read the sections and symbols from an object file.
template<int size, bool big_endian>
@ -514,6 +562,10 @@ Sized_relobj<size, big_endian>::do_read_symbols(Read_symbols_data* sd)
if (this->find_eh_frame(pshdrs, names, sd->section_names_size))
this->has_eh_frame_ = true;
}
if (memmem(names, sd->section_names_size, ".zdebug_", 8) != NULL)
this->compressed_sections_ =
build_compressed_section_map(pshdrs, this->shnum(), names,
sd->section_names_size, this);
sd->symbols = NULL;
sd->symbols_size = 0;

View file

@ -518,6 +518,13 @@ class Object
set_no_export(bool value)
{ this->no_export_ = value; }
// Return TRUE if the section is a compressed debug section, and set
// *UNCOMPRESSED_SIZE to the size of the uncompressed data.
bool
section_is_compressed(unsigned int shndx,
section_size_type* uncompressed_size) const
{ return this->do_section_is_compressed(shndx, uncompressed_size); }
protected:
// Returns NULL for Objects that are not plugin objects. This method
// is overridden in the Pluginobj class.
@ -628,6 +635,12 @@ class Object
bool
handle_split_stack_section(const char* name);
// Return TRUE if the section is a compressed debug section, and set
// *UNCOMPRESSED_SIZE to the size of the uncompressed data.
virtual bool
do_section_is_compressed(unsigned int, section_size_type*) const
{ return false; }
private:
// This class may not be copied.
Object(const Object&);
@ -1406,6 +1419,10 @@ class Reloc_symbol_changes
std::vector<Symbol*> vec_;
};
// Type for mapping section index to uncompressed size.
typedef std::map<unsigned int, section_size_type> Compressed_section_map;
// A regular object file. This is size and endian specific.
template<int size, bool big_endian>
@ -1781,7 +1798,26 @@ class Sized_relobj : public Relobj
void
set_output_local_symbol_count(unsigned int value)
{ this->output_local_symbol_count_ = value; }
// Return TRUE if the section is a compressed debug section, and set
// *UNCOMPRESSED_SIZE to the size of the uncompressed data.
bool
do_section_is_compressed(unsigned int shndx,
section_size_type* uncompressed_size) const
{
if (this->compressed_sections_ == NULL)
return false;
Compressed_section_map::const_iterator p =
this->compressed_sections_->find(shndx);
if (p != this->compressed_sections_->end())
{
if (uncompressed_size != NULL)
*uncompressed_size = p->second;
return true;
}
return false;
}
private:
// For convenience.
typedef Sized_relobj<size, big_endian> This;
@ -2024,6 +2060,8 @@ class Sized_relobj : public Relobj
std::vector<Deferred_layout> deferred_layout_;
// The list of relocation sections whose layout was deferred.
std::vector<Deferred_layout> deferred_layout_relocs_;
// For compressed debug sections, map section index to uncompressed size.
Compressed_section_map* compressed_sections_;
};
// A class to manage the list of all objects.

View file

@ -2086,8 +2086,13 @@ Output_section::add_input_section(Layout* layout,
}
}
section_size_type input_section_size = shdr.get_sh_size();
section_size_type uncompressed_size;
if (object->section_is_compressed(shndx, &uncompressed_size))
input_section_size = uncompressed_size;
this->set_current_data_size_for_child(aligned_offset_in_section
+ shdr.get_sh_size());
+ input_section_size);
// We need to keep track of this section if we are already keeping
// track of sections, or if we are relaxing. Also, if this is a

View file

@ -32,6 +32,7 @@
#include "target-reloc.h"
#include "reloc.h"
#include "icf.h"
#include "compressed_output.h"
namespace gold
{
@ -732,10 +733,17 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
off_t view_start;
section_size_type view_size;
bool must_decompress = false;
if (output_offset != invalid_address)
{
view_start = output_section_offset + output_offset;
view_size = convert_to_section_size_type(shdr.get_sh_size());
section_size_type uncompressed_size;
if (this->section_is_compressed(i, &uncompressed_size))
{
view_size = uncompressed_size;
must_decompress = true;
}
}
else
{
@ -754,7 +762,7 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
{
unsigned char* buffer = os->postprocessing_buffer();
view = buffer + view_start;
if (output_offset != invalid_address)
if (output_offset != invalid_address && !must_decompress)
{
off_t sh_offset = shdr.get_sh_offset();
if (!rm.empty() && rm.back().file_offset > sh_offset)
@ -770,14 +778,27 @@ Sized_relobj<size, big_endian>::write_sections(const unsigned char* pshdrs,
else
{
view = of->get_output_view(view_start, view_size);
off_t sh_offset = shdr.get_sh_offset();
if (!rm.empty() && rm.back().file_offset > sh_offset)
is_sorted = false;
rm.push_back(File_read::Read_multiple_entry(sh_offset,
view_size, view));
if (!must_decompress)
{
off_t sh_offset = shdr.get_sh_offset();
if (!rm.empty() && rm.back().file_offset > sh_offset)
is_sorted = false;
rm.push_back(File_read::Read_multiple_entry(sh_offset,
view_size, view));
}
}
}
if (must_decompress)
{
// Read and decompress the section.
section_size_type len;
const unsigned char* p = this->section_contents(i, &len, false);
if (!decompress_input_section(p, len, view, view_size))
this->error(_("could not decompress section %s"),
this->section_name(i).c_str());
}
pvs->view = view;
pvs->address = os->address();
if (output_offset != invalid_address)