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, 1 deletions

diff --git a/bfd/compress.c b/bfd/compress.c
index 0087a66..ad1fbee 100644
--- a/bfd/compress.c
+++ b/bfd/compress.c
@@ -441,7 +441,18 @@ bfd_init_section_compress_status (bfd *abfd ATTRIBUTE_UNUSED,
 					 uncompressed_buffer,
 					 uncompressed_size);
 
-  free (uncompressed_buffer);
+  /* PR binutils/18087: If compression didn't make
+     the section smaller, just keep it uncompressed.  */
+  if (ret && uncompressed_size < sec->size)
+    {
+      free (sec->contents);
+      sec->contents = uncompressed_buffer;
+      sec->size = uncompressed_size;
+      sec->compress_status = COMPRESS_SECTION_NONE;
+    }
+  else
+    free (uncompressed_buffer);
+
   return ret;
 #endif
 }