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PATCH COMMITTED: Handle large output sections in gold

Ian Lance Taylor iant@google.com
Thu Jul 10 23:09:00 GMT 2008 
For speed on 32-bit hosts, gold holds some section offsets using the
types size_t and ptrdiff_t.  It does this when the output sections
must be in memory anyhow, as with a merged section.

Unfortunately, I made a mistake and also did this with the offset of
an input section in an output section.  This fails when the output
section is more than 0x7fffffff bytes.  This will generally not happen
for a 32-bit target, but it can reasonably happen for a 64-bit target
if the output file is very large.

This patch fixes the problem.  Previously a single structure,
Map_to_output, hold the output section and the offset within the
output section.  That structure was in Relobj.  I moved the offset
within the output section to Sized_relobj.  That permits it to remain
a 32-bit value for a 32-bit target.

The rest of the patch is fairly mechanical changes that result from
that.  The comdat group support moves to Sized_relobj.  A bunch of
pointers which converted from Relobj* to Sized_relobj* now remain as
Sized_relobj* through a series of function calls.

The biggest change is that Symbol_table::sized_finalize_symbol now
calls a virtual function to get the section offset.  If this turns out
to be a problem, we can templatize Symbol_table::sized_finalize on the
endianness and use a static cast in sized_finalize_symbol.

Ian


2008-07-10  Ian Lance Taylor  <iant@google.com>

	Handle output sections with more than 0x7fffffff bytes.
	* object.h (class Relobj): Change map_to_output_ to
	output_sections_, and just keep a section pointer.  Change all
	uses.  Move comdat group support to Sized_relobj.
	(Relobj::is_section_specially_mapped): Remove.
	(Relobj::output_section): Remove poff parameter.  Change all
	callers.
	(Relobj::output_section_offset): New function.
	(Relobj::set_section_offset): Rewrite.
	(Relobj::map_to_output): Remove.
	(Relobj::output_sections): New function.
	(Relobj::do_output_section_offset): New pure virtual function.
	(Relobj::do_set_section_offset): Likewise.
	(class Sized_relobj): Add section_offsets_ field.  Add comdat
	group support from Relobj.  Update declarations.
	(Sized_relobj::get_output_section_offset): New function.
	(Sized_relobj::do_output_section_offset): New function.
	(Sized_relobj::do_set_section_offset): New function.
	* object.cc (Relobj::output_section_address): Remove.
	(Sized_relobj::Sized_relobj): Initialize new fields.
	(Sized_relobj::include_section_group): Cast find_kept_object to
	Sized_relobj.
	(Sized_relobj::include_linkonce_section): Likewise.
	(Sized_relobj::do_layout): Use separate arrays for output section
	and output offset.
	(Sized_relobj::do_count_local_symbols): Change map_to_output to
	output_sections.
	(Sized_relobj::do_finalize_local_symbols): Change map_to_output to
	output_sections and section_offsets.
	(Sized_relobj::write_local_symbols): Likewise.
	(map_to_kept_section): Compute output address directly.
	* reloc.cc (Sized_relobj::do_read_relocs): Change map_to_output to
	output_sections and section_offsets.
	(Sized_relobj::write_sections): Likewise.
	(Sized_relobj::relocate_sections): Likewise.
	* symtab.cc (sized_finalize_symbol): Use output_section_offset.
	* output.h (class Output_reloc): Update declarations.  Change
	u2_.relobj to Sized_relobj*.
	(class Output_data_reloc): Change add functions to use
	Sized_relobj*.
	* output.cc (Output_reloc::Output_reloc): Change relobj to
	Sized_relobj*.
	(Output_reloc::local_section_offset): Change return type to
	Elf_Addr.  Use get_output_section_offset.
	(Output_reloc::get_address): Likewise.
	(Output_section::is_input_address_mapped): Don't call
	is_section_specially_mapped.
	(Output_section::output_offset): Likewise.
	(Output_section::output_address): Likewise.
	(Output_section::starting_output_address): Likewise.
	* copy-relocs.cc (Copy_relocs::copy_reloc): Change object
	parameter to Sized_relobj*.
	(Copy_relocs::need_copy_reloc): Likewise.
	(Copy_relocs::save): Likewise.
	* copy-relocs.h (class Copy_relocs): Update declarations.
	(class Copy_relocs::Copy_reloc_entry): Change constructor to use
	Sized_relobj*.  Change relobj_ field to Sized_relobj*.
	* target-reloc.h (relocate_for_relocatable): Change
	offset_in_output_section type to Elf_Addr.  Change code that uses
	it as well.
	* layout.cc (Layout::layout): Always set *off.
	* mapfile.cc (Mapfile::print_input_section): Use
	output_section_offset.
	* i386.cc (Target_i386::copy_reloc): Change object parameter to
	Sized_relobj*.
	* powerpc.cc (Target_powerpc::copy_reloc): Likewise.
	* sparc.cc (Target_sparc::copy_reloc): Likewise.
	* x86_64.cc (Target_x86_64::copy_reloc): Likewise.


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