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, 12 insertions, 9 deletions

diff --git a/bfd/coffgen.c b/bfd/coffgen.c
index 5c664a4..b1ab56e 100644
--- a/bfd/coffgen.c
+++ b/bfd/coffgen.c
@@ -178,18 +178,21 @@ make_a_section_from_file (bfd *abfd,
 		 abfd, name);
 	      return FALSE;
 	    }
-	  if (name[1] != 'z')
+	  if (return_section->compress_status == COMPRESS_SECTION_DONE)
 	    {
-	      unsigned int len = strlen (name);
+	      if (name[1] != 'z')
+		{
+		  unsigned int len = strlen (name);
 
-	      new_name = bfd_alloc (abfd, len + 2);
-	      if (new_name == NULL)
-		return FALSE;
-	      new_name[0] = '.';
-	      new_name[1] = 'z';
-	      memcpy (new_name + 2, name + 1, len);
+		  new_name = bfd_alloc (abfd, len + 2);
+		  if (new_name == NULL)
+		    return FALSE;
+		  new_name[0] = '.';
+		  new_name[1] = 'z';
+		  memcpy (new_name + 2, name + 1, len);
+		}
 	    }
-	  break;
+         break;
 	case decompress:
 	  if (!bfd_init_section_decompress_status (abfd, return_section))
 	    {