[PATCH] [PR binutils/15350] Fix compressed debug sections for PE targets

[Alan Modra]

On Fri, Dec 27, 2019 at 07:47:44PM +0100, Hannes Domani via binutils wrote:
> When objcopy --compress-debug-sections was used, it actually did the
> compression, but the zlib header was not written, so the resulting debug info
> was invalid.
> 
> bfd/ChangeLog:
> 
> 2019-12-27  Hannes Domani  <ssbssa@yahoo.de>
> 
> 	* bfd.c (bfd_update_compression_header):
> 	Write zlib header for compressed debug sections of PE files.

Thanks!  I'm going to commit the following variation on your patch.
diff -w shown to omit indentation changes.

	PR 15350
	* bfd.c (bfd_update_compression_header): Write zlib header for
	formats other than ELF too.

diff --git a/bfd/bfd.c b/bfd/bfd.c
index a3c522cbf8..b6821fa20f 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -2540,22 +2540,22 @@ 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) == 0)
+    abort ();
+
+  switch (bfd_get_flavour (abfd))
     {
+    case bfd_target_elf_flavour:
       if ((abfd->flags & BFD_COMPRESS_GABI) != 0)
 	{
-	      const struct elf_backend_data *bed
-		= get_elf_backend_data (abfd);
+	  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;
+	      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,
@@ -2565,8 +2565,7 @@ bfd_update_compression_header (bfd *abfd, bfd_byte *contents,
 	    }
 	  else
 	    {
-		  Elf64_External_Chdr *echdr
-		    = (Elf64_External_Chdr *) contents;
+	      Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
 	      bfd_put_32 (abfd, ELFCOMPRESS_ZLIB, &echdr->ch_type);
 	      bfd_put_32 (abfd, 0, &echdr->ch_reserved);
 	      bfd_put_64 (abfd, sec->size, &echdr->ch_size);
@@ -2575,12 +2574,14 @@ bfd_update_compression_header (bfd *abfd, bfd_byte *contents,
 	      /* bfd_log2 (alignof (Elf64_Chdr)) */
 	      bfd_set_section_alignment (sec, 3);
 	    }
+	  break;
 	}
-	  else
-	    {
+
       /* Clear the SHF_COMPRESSED bit.  */
       elf_section_flags (sec) &= ~SHF_COMPRESSED;
+      /* Fall through.  */
 
+    default:
       /* Write the zlib header.  It should be "ZLIB" followed by
 	 the uncompressed section size, 8 bytes in big-endian
 	 order.  */
@@ -2588,12 +2589,9 @@ bfd_update_compression_header (bfd *abfd, bfd_byte *contents,
       bfd_putb64 (sec->size, contents + 4);
       /* No way to keep the original alignment, just use 1 always. */
       bfd_set_section_alignment (sec, 0);
+      break;
     }
 }
-    }
-  else
-    abort ();
-}
 
 /*
    FUNCTION

-- 
Alan Modra
Australia Development Lab, IBM