Add --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi]

This patch adds --compress-debug-sections=[none|zlib|zlib-gnu|zlib-gabi]
to ld for ELF targets to support generating compressed DWARF debug
sections.  We always generate .zdebug_* section since section names have
been finalized and they can't be changed easily when compression is
being performed.

bfd/

	* bfd-in.h (compressed_debug_section_type): New.
	* compress.c (bfd_compress_section_contents): Add an argument
	for linker write compression and always generate .zdebug_*
	section when linking.
	(bfd_init_section_compress_status): Pass FALSE to
	bfd_compress_section_contents.
	(bfd_compress_section): New function.
	* elf.c (elf_fake_sections): For linking, set SEC_ELF_COMPRESS
	on DWARF debug sections if COMPRESS_DEBUG is set and rename
	section if COMPRESS_DEBUG_GABI_ZLIB isn't set.
	(assign_file_positions_for_non_load_sections): Set sh_offset
	to -1 if SEC_ELF_COMPRESS is set.
	(assign_file_positions_except_relocs): Likwise.
	(_bfd_elf_assign_file_positions_for_relocs): Renamed to ...
	(_bfd_elf_assign_file_positions_for_non_load): This.  Change
	return time to bfd_boolean.  Compress the section if
	SEC_ELF_COMPRESS is set.
	(_bfd_elf_write_object_contents): Updated.
	(_bfd_elf_set_section_contents): Write section contents to
	the buffer if SEC_ELF_COMPRESS is set.
	* merge.c: Include "elf-bfd.h".
	(sec_merge_emit): Add arguments for contents and offset.  Write
	to contents with offset if contents isn't NULL.
	(_bfd_write_merged_section): Write section contents to the
	buffer if SEC_ELF_COMPRESS is set.  Pass contents and
	output_offset to sec_merge_emit.
	* elflink.c (bfd_elf_final_link): Allocate the buffer for
	output section contents if SEC_ELF_COMPRESS is set.
	* section.c (SEC_ELF_COMPRESS): New.
	* bfd-in2.h: Regenerated.

gas/

	* as.h (compressed_debug_section_type): Removed.

include/

	* bfdlink.h (bfd_link_info): Add compress_debug.

ld/

	* ld.texinfo: Document --compress-debug-sections=.
	* ldmain.c (main): Set BFD_COMPRESS on output_bfd if
	COMPRESS_DEBUG is set.  Set BFD_COMPRESS_GABI on output_bfd
	for COMPRESS_DEBUG_GABI_ZLIB.
	* lexsup.c (elf_static_list_options): Add
	--compress-debug-sections=.
	* emultempl/elf32.em (OPTION_COMPRESS_DEBUG): New.
	(xtra_long): Add "compress-debug-sections".
	(gld${EMULATION_NAME}_handle_option): Handle
	OPTION_COMPRESS_DEBUG.

ld/testsuite/

	* ld-elf/compress.exp (build_tests): Add tests for
	--compress-debug-sections=.
	(run_tests): Likewise.
	Add additonal tests for --compress-debug-sections=.
	* ld-elf/gabiend.rt: New file.
	* ld-elf/gabinormal.rt: Likewise.
	* ld-elf/gnubegin.rS: Likewise.
	* ld-elf/gnunormal.rS: Likewise.
	* ld-elf/zlibbegin.rS: Likewise.
	* ld-elf/zlibnormal.rS: Likewise.

1 files changed, 47 insertions, 4 deletions

diff --git a/bfd/compress.c b/bfd/compress.c
index 770ea57..dfde50e 100644
--- a/bfd/compress.c
+++ b/bfd/compress.c
@@ -72,7 +72,8 @@ decompress_contents (bfd_byte *compressed_buffer,
 static bfd_size_type
 bfd_compress_section_contents (bfd *abfd, sec_ptr sec,
 			       bfd_byte *uncompressed_buffer,
-			       bfd_size_type uncompressed_size)
+			       bfd_size_type uncompressed_size,
+			       bfd_boolean write_compress)
 {
   uLong compressed_size;
   bfd_byte *buffer;
@@ -176,8 +177,11 @@ bfd_compress_section_contents (bfd *abfd, sec_ptr sec,
 
       compressed_size += header_size;
       /* PR binutils/18087: If compression didn't make the section smaller,
-	 just keep it uncompressed.  */
-      if (compressed_size < uncompressed_size)
+	 just keep it uncompressed.  We always generate .zdebug_* section
+	 when linking since section names have been finalized and they
+	 can't be changed easily.  */
+      if ((write_compress && compression_header_size == 0)
+	   || compressed_size < uncompressed_size)
 	{
 	  bfd_update_compression_header (abfd, buffer, sec);
 
@@ -543,9 +547,48 @@ bfd_init_section_compress_status (bfd *abfd, sec_ptr sec)
     {
       uncompressed_size = bfd_compress_section_contents (abfd, sec,
 							 uncompressed_buffer,
-							 uncompressed_size);
+							 uncompressed_size,
+							 FALSE);
       ret = uncompressed_size != 0;
     }
 
   return ret;
 }
+
+/*
+FUNCTION
+	bfd_compress_section
+
+SYNOPSIS
+	bfd_boolean bfd_compress_section
+	  (bfd *abfd, asection *section, bfd_byte *uncompressed_buffer);
+
+DESCRIPTION
+	If open for write, compress section, update section size with
+	compressed size and set compress_status to COMPRESS_SECTION_DONE.
+
+	Return @code{FALSE} if compression fail.  Otherwise, return
+	@code{TRUE}.
+*/
+
+bfd_boolean
+bfd_compress_section (bfd *abfd, sec_ptr sec, bfd_byte *uncompressed_buffer)
+{
+  bfd_size_type uncompressed_size = sec->size;
+
+  /* Error if not opened for write.  */
+  if (abfd->direction != write_direction
+      || uncompressed_size == 0
+      || uncompressed_buffer == NULL
+      || sec->contents != NULL
+      || sec->compressed_size != 0
+      || sec->compress_status != COMPRESS_SECTION_NONE)
+    {
+      bfd_set_error (bfd_error_invalid_operation);
+      return FALSE;
+    }
+
+  /* Compress it.  */
+  return bfd_compress_section_contents (abfd, sec, uncompressed_buffer,
+					uncompressed_size, TRUE) != 0;
+}