Re: [gold patch] GDB index 2/2: Add --gdb-index option

[Ian Lance Taylor <iant at google dot com>]

Cary Coutant <ccoutant@google.com> writes:

> 2012-03-08  Cary Coutant  <ccoutant@google.com>
>
> 	* Makefile.am: Add gdb-index.cc, gdb-index.h.
> 	* Makefile.in: Regenerate.
> 	* dwarf_reader.cc (Sized_elf_reloc_mapper::do_initialize): New function.
> 	(Sized_elf_reloc_mapper::symbol_section): New function.
> 	(Sized_elf_reloc_mapper::do_get_reloc_target): New function.
> 	(make_elf_reloc_mapper): New function.
> 	(Dwarf_abbrev_table::clear_abbrev_codes): New function.
> 	(Dwarf_abbrev_table::do_read_abbrevs): New function.
> 	(Dwarf_abbrev_table::do_get_abbrev): New function.
> 	(Dwarf_ranges_table::read_ranges_table): New function.
> 	(Dwarf_ranges_table::read_range_list): New function.
> 	(Dwarf_pubnames_table::read_section): New function.
> 	(Dwarf_pubnames_table::read_header): New function.
> 	(Dwarf_pubnames_table::next_name): New function.
> 	(Dwarf_die::Dwarf_die): New function.
> 	(Dwarf_die::read_attributes): New function.
> 	(Dwarf_die::skip_attributes): New function.
> 	(Dwarf_die::set_name): New function.
> 	(Dwarf_die::set_linkage_name): New function.
> 	(Dwarf_die::attribute): New function.
> 	(Dwarf_die::string_attribute): New function.
> 	(Dwarf_die::int_attribute): New function.
> 	(Dwarf_die::uint_attribute): New function.
> 	(Dwarf_die::ref_attribute): New function.
> 	(Dwarf_die::child_offset): New function.
> 	(Dwarf_die::sibling_offset): New function.
> 	(Dwarf_info_reader::check_buffer): New function.
> 	(Dwarf_info_reader::parse): New function.
> 	(Dwarf_info_reader::do_parse): New function.
> 	(Dwarf_info_reader::do_read_string_table): New function.
> 	(Dwarf_info_reader::lookup_reloc): New function.
> 	(Dwarf_info_reader::get_string): New function.
> 	(Dwarf_info_reader::visit_compilation_unit): New function.
> 	(Dwarf_info_reader::visit_type_unit): New function.
> 	(Sized_dwarf_line_info::Sized_dwarf_line_info): Use
> 	Sized_elf_reloc_mapper.
> 	(Sized_dwarf_line_info::symbol_section): Remove function.
> 	(Sized_dwarf_line_info::read_relocs): Use Sized_elf_reloc_mapper.
> 	(Sized_dwarf_line_info::read_line_mappings): Remove object
> 	parameter, adjust callers.
> 	(Sized_dwarf_line_info::format_file_lineno): Fix type of cast.
> 	* dwarf_reader.h: Include <sys/types.h>.
> 	(class Track_relocs): Remove forward declaration.
> 	(class Elf_reloc_mapper): New class.
> 	(class Sized_elf_reloc_mapper): New class.
> 	(class Dwarf_abbrev_table): New class.
> 	(class Dwarf_range_list): New class.
> 	(class Dwarf_ranges_table): New class.
> 	(class Dwarf_pubnames_table): New class.
> 	(class Dwarf_die): New class.
> 	(class Dwarf_info_reader): New class.
> 	(Sized_dwarf_line_info::read_line_mappings): Remove object parameter.
> 	(Sized_dwarf_line_info::symbol_section): Remove member function.
> 	* dynobj.h (Sized_dynobj::do_section_contents): Refactor code from
> 	base class.
> 	* gdb-index.cc: New source file.
> 	* gdb-index.h: New source file.
> 	* incremental.cc (Sized_relobj_incr::do_layout): Track .debug_info
> 	and .debug_types sections, call Layout::add_to_gdb_index.
> 	(Sized_relobj_incr::do_section_name): Implement.
> 	(Sized_relobj_incr::do_section_contents): Adjust parameter list and
> 	return type; Implement.
> 	(Sized_incr_dynobj::do_section_contents): Adjust parameter list and
> 	return type.
> 	* incremental.h (Sized_relobj_incr::do_section_contents): Adjust
> 	parameter list and return type.
> 	(Sized_incr_dynobj::do_section_contents): Likewise.
> 	* layout.cc: Include gdb-index.h.
> 	(Layout::Layout): Initialize gdb_index_data_.
> 	(Layout::init_fixed_output_section): Check for .gdb_index section.
> 	(Layout::add_to_gdb_index): New function. Instantiate.
> 	* layout.h: Add forward declaration for class Gdb_index.
> 	(Layout::add_to_gdb_index): New member function.
> 	(Layout::gdb_index_data_): New data member.
> 	* main.cc: Include gdb-index.h.
> 	(main): Print statistics for gdb index.
> 	* object.cc (Object::section_contents): Move code into
> 	do_section_contents.
> 	(need_decompressed_section): Check for sections needed when building
> 	gdb index.
> 	(build_compressed_section_map): Likewise.
> 	(Sized_relobj_file::do_read_symbols): Need local symbols when building
> 	gdb index.
> 	(Sized_relobj_file::do_layout): Track .debug_info and .debug_types
> 	sections; call Layout::add_to_gdb_index.
> 	(Sized_relobj_file::do_decompressed_section_contents): Call
> 	do_section_contents directly.
> 	* object.h (Object::do_section_contents): Adjust parameter list and
> 	return type.
> 	(Object::do_decompressed_section_contents): Call do_section_contents
> 	directly.
> 	(Sized_relobj_file::do_section_contents): Adjust parameter list and
> 	return type.
> 	* options.h (class General_options): Add --gdb-index option.
> 	* plugin.cc (Sized_pluginobj::do_section_contents): Adjust parameter
> 	list and return type.
> 	* plugin.h (Sized_pluginobj::do_section_contents): Likewise.
> 	* reloc.h (Track_relocs::checkpoint): New function.
> 	(Track_relocs::reset): New function.
>
> 	* testsuite/Makefile.am (gdb_index_test_1.sh, gdb_index_test_2.sh):
> 	New test cases.
> 	* testsuite/Makefile.in: Regenerate.
> 	* testsuite/gdb_index_test.cc: New test source file.
> 	* testsuite/gdb_index_test_1.sh: New test source file.
> 	* testsuite/gdb_index_test_2.sh: New test source file.



> diff --git a/gold/dwarf_reader.cc b/gold/dwarf_reader.cc
> index 73f84b0..d4f6b24 100644
> --- a/gold/dwarf_reader.cc
> +++ b/gold/dwarf_reader.cc

> +template<int size, bool big_endian>
> +unsigned int
> +Sized_elf_reloc_mapper<size, big_endian>::symbol_section(
> +    unsigned int symndx, Address* value, bool* is_ordinary)
> +{
> +  const int symsize = elfcpp::Elf_sizes<size>::sym_size;
> +  gold_assert(symndx * symsize < this->symtab_size_);

(symndx + 1) * symsize <= this->symtab_size_



> +// Lookup the abbrev code entry for CODE.  This function is called
> +// only when the abbrev code is not in the direct lookup table.
> +// It may be in the hash table, it may not have been read yet,
> +// or it may not exist in the abbrev table.
> +
> +const Dwarf_abbrev_table::Abbrev_code*
> +Dwarf_abbrev_table::do_get_abbrev(unsigned int code)
> +{
> +  // See if the abbrev code is already in the hash table.
> +  Abbrev_code_table::const_iterator it = this->high_abbrev_codes_.find(code);
> +  if (it != this->high_abbrev_codes_.end())
> +    return it->second;
> +
> +  // Read and store abbrev code definitions until we find the
> +  // one we're looking for.
> +  while (this->buffer_pos_ < this->buffer_end_)
> +    {

I don't understand why you have this outer while loop.  The structure of
this function seems to be

  while (cond)
    {
      for (;;)
        {
          // maybe return
          for (;;)
            {
              // maybe return
              // maybe break
            }
        }
    }

The middle loop never breaks, so as far as I can see the outer while
loop serves no purpose.  The only way out of this function is via an
explicit return statement.


> +// Copyright 2011 Free Software Foundation, Inc.
> +// Written by Cary Coutant <ccoutant@google.com>.

2012.


This is OK with those issues fixed.

Thanks.

Ian