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, 43 insertions, 10 deletions

diff --git a/bfd/merge.c b/bfd/merge.c
index 5f45ba6e106..174ec90bff2 100644
--- a/bfd/merge.c
+++ b/bfd/merge.c
@@ -25,6 +25,7 @@
 
 #include "sysdep.h"
 #include "bfd.h"
+#include "elf-bfd.h"
 #include "libbfd.h"
 #include "hashtab.h"
 #include "libiberty.h"
@@ -283,7 +284,8 @@ sec_merge_add (struct sec_merge_hash *tab, const char *str,
 }
 
 static bfd_boolean
-sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry)
+sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry,
+		unsigned char *contents, file_ptr offset)
 {
   struct sec_merge_sec_info *secinfo = entry->secinfo;
   asection *sec = secinfo->sec;
@@ -306,7 +308,12 @@ sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry)
       len = -off & (entry->alignment - 1);
       if (len != 0)
 	{
-	  if (bfd_bwrite (pad, len, abfd) != len)
+	  if (contents)
+	    {
+	      memcpy (contents + offset, pad, len);
+	      offset += len;
+	    }
+	  else if (bfd_bwrite (pad, len, abfd) != len)
 	    goto err;
 	  off += len;
 	}
@@ -314,7 +321,12 @@ sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry)
       str = entry->root.string;
       len = entry->len;
 
-      if (bfd_bwrite (str, len, abfd) != len)
+      if (contents)
+	{
+	  memcpy (contents + offset, str, len);
+	  offset += len;
+	}
+      else if (bfd_bwrite (str, len, abfd) != len)
 	goto err;
 
       off += len;
@@ -322,9 +334,13 @@ sec_merge_emit (bfd *abfd, struct sec_merge_hash_entry *entry)
 
   /* Trailing alignment needed?  */
   off = sec->size - off;
-  if (off != 0
-      && bfd_bwrite (pad, off, abfd) != off)
-    goto err;
+  if (off != 0)
+    {
+      if (contents)
+	memcpy (contents + offset, pad, off);
+      else if (bfd_bwrite (pad, off, abfd) != off)
+	goto err;
+    }
 
   if (pad != NULL)
     free (pad);
@@ -785,6 +801,8 @@ _bfd_write_merged_section (bfd *output_bfd, asection *sec, void *psecinfo)
 {
   struct sec_merge_sec_info *secinfo;
   file_ptr pos;
+  unsigned char *contents;
+  Elf_Internal_Shdr *hdr;
 
   secinfo = (struct sec_merge_sec_info *) psecinfo;
 
@@ -795,11 +813,26 @@ _bfd_write_merged_section (bfd *output_bfd, asection *sec, void *psecinfo)
     return TRUE;
 
   /* FIXME: octets_per_byte.  */
-  pos = sec->output_section->filepos + sec->output_offset;
-  if (bfd_seek (output_bfd, pos, SEEK_SET) != 0)
-    return FALSE;
+  hdr = &elf_section_data (sec->output_section)->this_hdr;
+  if (hdr->sh_offset == (file_ptr) -1)
+    {
+      /* We must compress this section.  Write output to the
+	 buffer.  */
+      contents = hdr->contents;
+      if ((sec->output_section->flags & SEC_ELF_COMPRESS) == 0
+	  || contents == NULL)
+	abort ();
+    }
+  else
+    {
+      contents = NULL;
+      pos = sec->output_section->filepos + sec->output_offset;
+      if (bfd_seek (output_bfd, pos, SEEK_SET) != 0)
+	return FALSE;
+    }
 
-  if (! sec_merge_emit (output_bfd, secinfo->first_str))
+  if (! sec_merge_emit (output_bfd, secinfo->first_str, contents,
+			sec->output_offset))
     return FALSE;
 
   return TRUE;