Add .gdb_index version 7 support.

This patch adds support for .gdb_index version 7, which adds several
flag bits to the symbol index.  It also fixes a problem where it did
not handle compressed debug sections correctly.

Tested with a google/gcc-4_8 branch compiler, which supports
the -ggnu-pubnames option to generate .debug_gnu_pubnames/pubtypes
tables. (We will submit that patch to GCC when stage 1 reopens.)

2014-01-28  Cary Coutant  <ccoutant@google.com>

	* gold/dwarf_reader.cc: include <utility> (for make_pair).
	(Dwarf_abbrev_table::do_read_abbrevs): Check for compressed
	debug sections.
	(Dwarf_ranges_table::read_ranges_table): Likewise.
	(Dwarf_pubnames_table::read_section): Check for GNU-style
	sections, and for compressed debug sections.
	(Dwarf_pubnames_table::read_header): Compute end address of table.
	(Dwarf_pubnames_table::next_name): Return flag_byte.  Check
	for end of list by offset, not by offset == 0.
	(Dwarf_info_reader::do_read_string_table): Check for compressed
	debug sections.
	* gold/dwarf_reader.h (Dwarf_pubnames_table::Dwarf_pubnames_table):
	Initialize new data members.
	(Dwarf_pubnames_table::next_name): return flag_byte.
	(Dwarf_pubnames_table::end_of_table_): New data member.
	(Dwarf_pubnames_table::is_gnu_style_): New data member.
	* gold/gdb-index.cc (gdb_index_version): Update to version 7.
	(Gdb_index_info_reader::read_pubtable): Read flag_byte.
	(Gdb_index_info_reader::read_pubnames_and_pubtypes): Don't
	read skeleton type unit DIEs.
	(Gdb_index::add_symbol): Add flag_byte; adjust all callers.
	(Gdb_index::do_write): Write flag_byte.
	* gold/gdb-index.h (Gdb_index::add_symbol): Add flags parameter.
	(Gdb_index::Cu_vector): Store flags along with cu indexes.
	* gold/testsuite/gdb_index_test_3.sh: Allow versions 4-7.
	* gold/testsuite/gdb_index_test_comm.sh: Likewise.

1 files changed, 10 insertions, 3 deletions

diff --git a/gold/dwarf_reader.h b/gold/dwarf_reader.h
index bbd9667..3afc6e2 100644
--- a/gold/dwarf_reader.h
+++ b/gold/dwarf_reader.h
@@ -400,7 +400,8 @@ class Dwarf_pubnames_table
  public:
   Dwarf_pubnames_table(Dwarf_info_reader* dwinfo, bool is_pubtypes)
     : dwinfo_(dwinfo), buffer_(NULL), buffer_end_(NULL), owns_buffer_(false),
-      offset_size_(0), pinfo_(NULL), is_pubtypes_(is_pubtypes),
+      offset_size_(0), pinfo_(NULL), end_of_table_(NULL),
+      is_pubtypes_(is_pubtypes), is_gnu_style_(false),
       output_section_offset_(0), unit_length_(0), cu_offset_(0)
   { }
 
@@ -431,9 +432,10 @@ class Dwarf_pubnames_table
   subsection_size()
   { return this->unit_length_; }
 
-  // Read the next name from the set.
+  // Read the next name from the set.  If the pubname table is gnu-style,
+  // FLAG_BYTE is set to the high-byte of a gdb_index version 7 cu_index.
   const char*
-  next_name();
+  next_name(uint8_t* flag_byte);
 
  private:
   // The Dwarf_info_reader, for reading data.
@@ -447,8 +449,13 @@ class Dwarf_pubnames_table
   unsigned int offset_size_;
   // The current position within the buffer.
   const unsigned char* pinfo_;
+  // The end of the current pubnames table.
+  const unsigned char* end_of_table_;
   // TRUE if this is a .debug_pubtypes section.
   bool is_pubtypes_;
+  // Gnu-style pubnames table. This style has an extra flag byte between the
+  // offset and the name, and is used for generating version 7 of gdb-index.
+  bool is_gnu_style_;
   // For incremental update links, this will hold the offset of the
   // input section within the output section.  Offsets read from
   // relocated data will be relative to the output section, and need