Fix debug section compression so that it is only performed if it would make the section smaller.

	PR binutils/18087
gas	* doc/as.texinfo: Note that when gas compresses debug sections the
	compression is only performed if it makes the section smaller.
	* write.c (compress_debug): Do not compress a debug section if
	doing so would make it larger.

tests	* gas/i386/dw2-compress-1.d: Do not expect the .debug_abbrev or
	.debug_info sections to be compressed.

binu	* doc/binutils.texi: Note that when objcopy compresses debug
	sections the compression is only performed if it makes the section
	smaller.

bfd	* coffgen.c (make_a_section_from_file): Only prepend a z to a
	debug section's name if the section was actually compressed.
	* elf.c (_bfd_elf_make_section_from_shdr): Likewise.
	* compress.c (bfd_init_section_compress_status): Do not compress
	the section if doing so would make it bigger.  In such cases leave
	the section alone and return COMPRESS_SECTION_NONE.

1 files changed, 5 insertions, 0 deletions

diff --git a/gas/write.c b/gas/write.c
index 949ae92..e3570ac 100644
--- a/gas/write.c
+++ b/gas/write.c
@@ -1526,6 +1526,11 @@ compress_debug (bfd *abfd, asection *sec, void *xxx ATTRIBUTE_UNUSED)
 	break;
     }
 
+  /* PR binutils/18087: If compression didn't make
+     the section smaller, just keep it uncompressed.  */
+  if (compressed_size > sec->size)
+    return;
+  
   /* Replace the uncompressed frag list with the compressed frag list.  */
   seginfo->frchainP->frch_root = first_newf;
   seginfo->frchainP->frch_last = last_newf;