Add SHF_COMPRESSED support to gas and objcopy

This patch adds --compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}
options to gas and objcopy for ELF files. They control how DWARF debug
sections are compressed.  --compress-debug-sections=none is equivalent to
--nocompress-debug-sections.  --compress-debug-sections=zlib and
--compress-debug-sections=zlib-gnu are equivalent to
--compress-debug-sections.  --compress-debug-sections=zlib-gabi compresses
DWARF debug sections with SHF_COMPRESSED from the ELF ABI.  No linker
changes are required to support SHF_COMPRESSED.

bfd/

	* archive.c (_bfd_get_elt_at_filepos): Also copy BFD_COMPRESS_GABI
	bit.
	* bfd.c (bfd::flags): Increase size to 18 bits.
	(BFD_COMPRESS_GABI): New.
	(BFD_FLAGS_SAVED): Add BFD_COMPRESS_GABI.
	(BFD_FLAGS_FOR_BFD_USE_MASK): Likewise.
	(bfd_update_compression_header): New fuction.
	(bfd_check_compression_header): Likewise.
	(bfd_get_compression_header_size): Likewise.
	(bfd_is_section_compressed_with_header): Likewise.
	* compress.c (MAX_COMPRESSION_HEADER_SIZE): New.
	(bfd_compress_section_contents): Return the uncompressed size if
	the full section contents is compressed successfully.  Support
	converting from/to .zdebug* sections.
	(bfd_get_full_section_contents): Call
	bfd_get_compression_header_size to get compression header size.
	(bfd_is_section_compressed): Renamed to ...
	(bfd_is_section_compressed_with_header): This.  Add a pointer
	argument to return compression header size.
	(bfd_is_section_compressed): Use it.
	(bfd_init_section_decompress_status): Call
	bfd_get_compression_header_size to get compression header size.
	Return FALSE if uncompressed section size is 0.
	* elf.c (_bfd_elf_make_section_from_shdr): Support converting
	from/to .zdebug* sections.
	* bfd-in2.h: Regenerated.

binutils/

	* objcopy.c (do_debug_sections): Add compress_zlib,
	compress_gnu_zlib and compress_gabi_zlib.
	(copy_options): Use optional_argument on compress-debug-sections.
	(copy_usage): Update --compress-debug-sections.
	(copy_file): Handle compress_zlib, compress_gnu_zlib and
	compress_gabi_zlib.
	(copy_main): Handle
	--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
	* doc/binutils.texi: Document
	--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.

binutils/testsuite/

	* compress.exp: Add tests for
	--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
	* binutils-all/dw2-3.rS: New file.
	* binutils-all/dw2-3.rt: Likewise.
	* binutils-all/libdw2-compressedgabi.out: Likewise.

gas/

	* as.c (show_usage): Update --compress-debug-sections.
	(std_longopts): Use optional_argument on compress-debug-sections.
	(parse_args): Handle
	--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
	* as.h (compressed_debug_section_type): New.
	(flag_compress_debug): Change type to compressed_debug_section_type.
	--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.
	* write.c (compress_debug): Set BFD_COMPRESS_GABI for
	--compress-debug-sections=zlib-gabi.  Call
	bfd_get_compression_header_size to get compression header size.
	Don't rename section name for --compress-debug-sections=zlib-gabi.
	* config/tc-i386.c (compressed_debug_section_type): Set to
	COMPRESS_DEBUG_ZLIB.
	* doc/as.texinfo: Document
	--compress-debug-sections={none|zlib|zlib-gnu|zlib-gabi}.

gas/testsuite/

	* gas/i386/dw2-compressed-1.d: New file.
	* gas/i386/dw2-compressed-2.d: Likewise.
	* gas/i386/dw2-compressed-3.d: Likewise.
	* gas/i386/x86-64-dw2-compressed-2.d: Likewise.
	* gas/i386/i386.exp: Run dw2-compressed-2, dw2-compressed-1,
	dw2-compressed-3 and x86-64-dw2-compressed-2.

ld/testsuite/

	* ld-elf/compress.exp: Add a test for
	--compress-debug-sections=zlib-gabi.
	(build_tests): Add 2 tests for --compress-debug-sections=zlib-gabi.
	(run_tests): Likewise.
	Verify linker output with zlib-gabi compressed debug input.
	* ld-elf/compressed1a.d: New file.
	* ld-elf/compressed1b.d: Likewise.
	* ld-elf/compressed1c.d: Likewise.

binutils/objcopy.c

@@ -204,6 +204,9 @@ static enum
 {
   nothing,
   compress,
+  compress_zlib,
+  compress_gnu_zlib,
+  compress_gabi_zlib,
   decompress
 } do_debug_sections = nothing;
 
@@ -380,7 +383,7 @@ static struct option copy_options[] =
   {"change-section-vma", required_argument, 0, OPTION_CHANGE_SECTION_VMA},
   {"change-start", required_argument, 0, OPTION_CHANGE_START},
   {"change-warnings", no_argument, 0, OPTION_CHANGE_WARNINGS},
-  {"compress-debug-sections", no_argument, 0, OPTION_COMPRESS_DEBUG_SECTIONS},
+  {"compress-debug-sections", optional_argument, 0, OPTION_COMPRESS_DEBUG_SECTIONS},
   {"debugging", no_argument, 0, OPTION_DEBUGGING},
   {"decompress-debug-sections", no_argument, 0, OPTION_DECOMPRESS_DEBUG_SECTIONS},
   {"disable-deterministic-archives", no_argument, 0, 'U'},
@@ -601,7 +604,8 @@ copy_usage (FILE *stream, int exit_status)
                                    <commit>\n\
      --subsystem <name>[:<version>]\n\
                                    Set PE subsystem to <name> [& <version>]\n\
-     --compress-debug-sections     Compress DWARF debug sections using zlib\n\
+     --compress-debug-sections[={none|zlib|zlib-gnu|zlib-gabi}]\n\
+                                   Compress DWARF debug sections using zlib\n\
      --decompress-debug-sections   Decompress DWARF debug sections using zlib\n\
   -v --verbose                     List all object files modified\n\
   @<file>                          Read options from <file>\n\
@@ -2588,7 +2592,18 @@ copy_file (const char *input_filename, const char *output_filename,
   switch (do_debug_sections)
     {
     case compress:
+    case compress_zlib:
+    case compress_gnu_zlib:
+    case compress_gabi_zlib:
       ibfd->flags |= BFD_COMPRESS;
+      if (do_debug_sections != compress)
+	{
+	  if (ibfd->xvec->flavour != bfd_target_elf_flavour)
+	    fatal (_("--compress-debug-sections=[zlib|zlib-gnu|zlib-gabi] is unsupported for `%s'"),
+		   bfd_get_target (ibfd));
+	  if (do_debug_sections == compress_gabi_zlib)
+	    ibfd->flags |= BFD_COMPRESS_GABI;
+	}
       break;
     case decompress:
       ibfd->flags |= BFD_DECOMPRESS;
@@ -3998,7 +4013,22 @@ copy_main (int argc, char *argv[])
 	  break;
 
 	case OPTION_COMPRESS_DEBUG_SECTIONS:
-	  do_debug_sections = compress;
+	  if (optarg)
+	    {
+	      if (strcasecmp (optarg, "none") == 0)
+		do_debug_sections = decompress;
+	      else if (strcasecmp (optarg, "zlib") == 0)
+		do_debug_sections = compress_zlib;
+	      else if (strcasecmp (optarg, "zlib-gnu") == 0)
+		do_debug_sections = compress_gnu_zlib;
+	      else if (strcasecmp (optarg, "zlib-gabi") == 0)
+		do_debug_sections = compress_gabi_zlib;
+	      else
+		fatal (_("unrecognized --compress-debug-sections type `%s'"),
+		       optarg);
+	    }
+	  else
+	    do_debug_sections = compress;
 	  break;
 
 	case OPTION_DEBUGGING: