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.

1 files changed, 150 insertions, 3 deletions

diff --git a/bfd/bfd.c b/bfd/bfd.c
index 5ae5eca..ba78cf3 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -85,7 +85,7 @@ CODE_FRAGMENT
 .  ENUM_BITFIELD (bfd_direction) direction : 2;
 .
 .  {* Format_specific flags.  *}
-.  flagword flags : 17;
+.  flagword flags : 18;
 .
 .  {* Values that may appear in the flags field of a BFD.  These also
 .     appear in the object_flags field of the bfd_target structure, where
@@ -162,14 +162,19 @@ CODE_FRAGMENT
 .  {* BFD is a dummy, for plugins.  *}
 .#define BFD_PLUGIN 0x10000
 .
+.  {* Compress sections in this BFD with SHF_COMPRESSED from gABI.  *}
+.#define BFD_COMPRESS_GABI 0x20000
+.
 .  {* Flags bits to be saved in bfd_preserve_save.  *}
 .#define BFD_FLAGS_SAVED \
-.  (BFD_IN_MEMORY | BFD_COMPRESS | BFD_DECOMPRESS | BFD_PLUGIN)
+.  (BFD_IN_MEMORY | BFD_COMPRESS | BFD_DECOMPRESS | BFD_PLUGIN \
+.   | BFD_COMPRESS_GABI)
 .
 .  {* Flags bits which are for BFD use only.  *}
 .#define BFD_FLAGS_FOR_BFD_USE_MASK \
 .  (BFD_IN_MEMORY | BFD_COMPRESS | BFD_DECOMPRESS | BFD_LINKER_CREATED \
-.   | BFD_PLUGIN | BFD_TRADITIONAL_FORMAT | BFD_DETERMINISTIC_OUTPUT)
+.   | BFD_PLUGIN | BFD_TRADITIONAL_FORMAT | BFD_DETERMINISTIC_OUTPUT \
+.   | BFD_COMPRESS_GABI)
 .
 .  {* Is the file descriptor being cached?  That is, can it be closed as
 .     needed, and re-opened when accessed later?  *}
@@ -1940,3 +1945,145 @@ bfd_demangle (bfd *abfd, const char *name, int options)
 
   return res;
 }
+
+/*
+FUNCTION
+	bfd_update_compression_header
+
+SYNOPSIS
+	void bfd_update_compression_header
+	  (bfd *abfd, bfd_byte *contents, asection *sec);
+
+DESCRIPTION
+	Set the compression header at CONTENTS of SEC in ABFD and update
+	elf_section_flags for compression.
+*/
+
+void
+bfd_update_compression_header (bfd *abfd, bfd_byte *contents,
+			       asection *sec)
+{
+  if ((abfd->flags & BFD_COMPRESS) != 0)
+    {
+      if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+	{
+	  if ((abfd->flags & BFD_COMPRESS_GABI) != 0)
+	    {
+	      const struct elf_backend_data *bed
+		= get_elf_backend_data (abfd);
+
+	      /* Set the SHF_COMPRESSED bit.  */
+	      elf_section_flags (sec) |= SHF_COMPRESSED;
+
+	      if (bed->s->elfclass == ELFCLASS32)
+		{
+		  Elf32_External_Chdr *echdr
+		    = (Elf32_External_Chdr *) contents;
+		  bfd_put_32 (abfd, ELFCOMPRESS_ZLIB, &echdr->ch_type);
+		  bfd_put_32 (abfd, sec->size, &echdr->ch_size);
+		  bfd_put_32 (abfd, 1 << sec->alignment_power,
+			      &echdr->ch_addralign);
+		}
+	      else
+		{
+		  Elf64_External_Chdr *echdr
+		    = (Elf64_External_Chdr *) contents;
+		  bfd_put_64 (abfd, ELFCOMPRESS_ZLIB, &echdr->ch_type);
+		  bfd_put_64 (abfd, sec->size, &echdr->ch_size);
+		  bfd_put_64 (abfd, 1 << sec->alignment_power,
+			      &echdr->ch_addralign);
+		}
+	    }
+	  else
+	    /* Clear the SHF_COMPRESSED bit.  */
+	    elf_section_flags (sec) &= ~SHF_COMPRESSED;
+	}
+    }
+  else
+    abort ();
+}
+
+/*
+   FUNCTION
+   bfd_check_compression_header
+
+   SYNOPSIS
+	bfd_boolean bfd_check_compression_header
+	  (bfd *abfd, bfd_byte *contents, asection *sec,
+	   bfd_size_type uncompressed_size);
+
+DESCRIPTION
+	Check the compression header at CONTENTS of SEC in ABFD with
+	the uncompressed size UNCOMPRESSED_SIZE.
+
+RETURNS
+	Return TRUE if the compression header is valid.
+*/
+
+bfd_boolean
+bfd_check_compression_header (bfd *abfd, bfd_byte *contents,
+			      asection *sec,
+			      bfd_size_type uncompressed_size)
+{
+  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
+      && (elf_section_flags (sec) & SHF_COMPRESSED) != 0)
+    {
+      Elf_Internal_Chdr chdr;
+      const struct elf_backend_data *bed = get_elf_backend_data (abfd);
+      if (bed->s->elfclass == ELFCLASS32)
+	{
+	  Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
+	  chdr.ch_type = bfd_get_32 (abfd, &echdr->ch_type);
+	  chdr.ch_size = bfd_get_32 (abfd, &echdr->ch_size);
+	  chdr.ch_addralign = bfd_get_32 (abfd, &echdr->ch_addralign);
+	}
+      else
+	{
+	  Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
+	  chdr.ch_type = bfd_get_64 (abfd, &echdr->ch_type);
+	  chdr.ch_size = bfd_get_64 (abfd, &echdr->ch_size);
+	  chdr.ch_addralign = bfd_get_64 (abfd, &echdr->ch_addralign);
+	}
+      return (chdr.ch_type == ELFCOMPRESS_ZLIB
+	      && chdr.ch_size == uncompressed_size
+	      && chdr.ch_addralign == 1U << sec->alignment_power);
+    }
+
+  return FALSE;
+}
+
+/*
+FUNCTION
+	bfd_get_compression_header_size
+
+SYNOPSIS
+	int bfd_get_compression_header_size (bfd *abfd, asection *sec);
+
+DESCRIPTION
+	Return the size of the compression header of SEC in ABFD.
+
+RETURNS
+	Return the size of the compression header in bytes.
+*/
+
+int
+bfd_get_compression_header_size (bfd *abfd, asection *sec)
+{
+  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+    {
+      if (sec == NULL)
+	{
+	  if (!(abfd->flags & BFD_COMPRESS_GABI))
+	    return 0;
+	}
+      else if (!(elf_section_flags (sec) & SHF_COMPRESSED))
+	return 0;
+
+      if (get_elf_backend_data (abfd)->s->elfclass == ELFCLASS32)
+	return sizeof (Elf32_External_Chdr);
+      else
+	return sizeof (Elf64_External_Chdr);
+    }
+
+  return 0;
+}