Compression header enum

Define an enum instead of using ELFCOMPRESS_ZLIB and ELFCOMPRESS_ZSTD
in bfd and binutils, and move some functions from bfd.c to compress.c.
When looking at the COFF/PE debug compression support, I wondered
about extending it to support zstd.  I likely won't do that, but
the compression header ch_type field isn't just ELF specific if these
headers are to be used in COFF/PE too.

bfd/
	* bfd.c (bfd_update_compression_header),
	(bfd_check_compression_header, bfd_get_compression_header_size),
	(bfd_convert_section_size, bfd_convert_section_contents): Move to..
	* compress.c: ..here.
	(enum compression_type): New.  Use it throughout file.
	* elf.c (_bfd_elf_make_section_from_shdr): Replace uses of
	ELFCOMPRESS_ZLIB and ELFCOMPRESS_ZSTD with ch_compress_zlib and
	ch_compress_zstd.
	* bfd-in2.h: Regenerate.
binutils/
	* readelf.c (process_section_headers, dump_section_as_strings),
	(dump_section_as_bytes, load_specific_debug_section): Replace
	uses of ELFCOMPRESS_ZLIB and ELFCOMPRESS_ZSTD with
	ch_compress_zlib and ch_compress_zstd.

5 files changed, 384 insertions, 392 deletions

diff --git a/bfd/bfd-in2.h b/bfd/bfd-in2.h
index 15f3c8c..24f9305 100644
--- a/bfd/bfd-in2.h
+++ b/bfd/bfd-in2.h
@@ -7286,24 +7286,6 @@ bfd_vma bfd_emul_get_commonpagesize (const char *);
 
 char *bfd_demangle (bfd *, const char *, int);
 
-void bfd_update_compression_header
-   (bfd *abfd, bfd_byte *contents, asection *sec);
-
-bool bfd_check_compression_header
-   (bfd *abfd, bfd_byte *contents, asection *sec,
-    unsigned int *ch_type,
-    bfd_size_type *uncompressed_size,
-    unsigned int *uncompressed_alignment_power);
-
-int bfd_get_compression_header_size (bfd *abfd, asection *sec);
-
-bfd_size_type bfd_convert_section_size
-   (bfd *ibfd, asection *isec, bfd *obfd, bfd_size_type size);
-
-bool bfd_convert_section_contents
-   (bfd *ibfd, asection *isec, bfd *obfd,
-    bfd_byte **ptr, bfd_size_type *ptr_size);
-
 /* Extracted from archive.c.  */
 symindex bfd_get_next_mapent
    (bfd *abfd, symindex previous, carsym **sym);
@@ -7963,6 +7945,13 @@ bfd_byte *bfd_simple_get_relocated_section_contents
    (bfd *abfd, asection *sec, bfd_byte *outbuf, asymbol **symbol_table);
 
 /* Extracted from compress.c.  */
+enum compression_type
+{
+  ch_none = 0,
+  ch_compress_zlib = 1 ,       /* Compressed with zlib.  */
+  ch_compress_zstd = 2         /* Compressed with zstd (www.zstandard.org).  */
+};
+
 static inline char *
 bfd_debug_name_to_zdebug (bfd *abfd, const char *name)
 {
@@ -7988,6 +7977,18 @@ bfd_zdebug_name_to_debug (bfd *abfd, const char *name)
   return new_name;
 }
 
+void bfd_update_compression_header
+   (bfd *abfd, bfd_byte *contents, asection *sec);
+
+int bfd_get_compression_header_size (bfd *abfd, asection *sec);
+
+bfd_size_type bfd_convert_section_size
+   (bfd *ibfd, asection *isec, bfd *obfd, bfd_size_type size);
+
+bool bfd_convert_section_contents
+   (bfd *ibfd, asection *isec, bfd *obfd,
+    bfd_byte **ptr, bfd_size_type *ptr_size);
+
 bool bfd_get_full_section_contents
    (bfd *abfd, asection *section, bfd_byte **ptr);
 
@@ -7996,7 +7997,7 @@ bool bfd_is_section_compressed_info
     int *compression_header_size_p,
     bfd_size_type *uncompressed_size_p,
     unsigned int *uncompressed_alignment_power_p,
-    unsigned int *ch_type);
+    enum compression_type *ch_type);
 
 bool bfd_is_section_compressed
    (bfd *abfd, asection *section);
diff --git a/bfd/bfd.c b/bfd/bfd.c
index b9d4aa4..8d9c9c6 100644
--- a/bfd/bfd.c
+++ b/bfd/bfd.c
@@ -2477,358 +2477,6 @@ bfd_demangle (bfd *abfd, const char *name, int options)
   return res;
 }
 
-/*
-FUNCTION
-	bfd_update_compression_header
-
-SYNOPSIS
-	void bfd_update_compression_header
-	  (bfd *abfd, bfd_byte *contents, asection *sec);
-
-DESCRIPTION
-	Set the compression header at CONTENTS of SEC in ABFD and update
-	elf_section_flags for compression.
-*/
-
-void
-bfd_update_compression_header (bfd *abfd, bfd_byte *contents,
-			       asection *sec)
-{
-  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);
-	  struct bfd_elf_section_data * esd = elf_section_data (sec);
-	  const unsigned int ch_type = abfd->flags & BFD_COMPRESS_ZSTD
-					   ? ELFCOMPRESS_ZSTD
-					   : ELFCOMPRESS_ZLIB;
-
-	  /* Set the SHF_COMPRESSED bit.  */
-	  elf_section_flags (sec) |= SHF_COMPRESSED;
-
-	  if (bed->s->elfclass == ELFCLASS32)
-	    {
-	      Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
-	      bfd_put_32 (abfd, ch_type, &echdr->ch_type);
-	      bfd_put_32 (abfd, sec->size, &echdr->ch_size);
-	      bfd_put_32 (abfd, 1u << sec->alignment_power,
-			  &echdr->ch_addralign);
-	      /* bfd_log2 (alignof (Elf32_Chdr)) */
-	      bfd_set_section_alignment (sec, 2);
-	      esd->this_hdr.sh_addralign = 4;
-	    }
-	  else
-	    {
-	      Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
-	      bfd_put_32 (abfd, ch_type, &echdr->ch_type);
-	      bfd_put_32 (abfd, 0, &echdr->ch_reserved);
-	      bfd_put_64 (abfd, sec->size, &echdr->ch_size);
-	      bfd_put_64 (abfd, UINT64_C (1) << sec->alignment_power,
-			  &echdr->ch_addralign);
-	      /* bfd_log2 (alignof (Elf64_Chdr)) */
-	      bfd_set_section_alignment (sec, 3);
-	      esd->this_hdr.sh_addralign = 8;
-	    }
-	  break;
-	}
-
-      /* 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.  */
-      memcpy (contents, "ZLIB", 4);
-      bfd_putb64 (sec->size, contents + 4);
-      /* No way to keep the original alignment, just use 1 always. */
-      bfd_set_section_alignment (sec, 0);
-      break;
-    }
-}
-
-/*
-   FUNCTION
-   bfd_check_compression_header
-
-   SYNOPSIS
-	bool bfd_check_compression_header
-	  (bfd *abfd, bfd_byte *contents, asection *sec,
-	  unsigned int *ch_type,
-	  bfd_size_type *uncompressed_size,
-	  unsigned int *uncompressed_alignment_power);
-
-DESCRIPTION
-	Check the compression header at CONTENTS of SEC in ABFD and store the
-	ch_type in CH_TYPE, uncompressed size in UNCOMPRESSED_SIZE, and the
-	uncompressed data alignment in UNCOMPRESSED_ALIGNMENT_POWER if the
-	compression header is valid.
-
-RETURNS
-	Return TRUE if the compression header is valid.
-*/
-
-bool
-bfd_check_compression_header (bfd *abfd, bfd_byte *contents,
-			      asection *sec,
-			      unsigned int *ch_type,
-			      bfd_size_type *uncompressed_size,
-			      unsigned int *uncompressed_alignment_power)
-{
-  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
-      && (elf_section_flags (sec) & SHF_COMPRESSED) != 0)
-    {
-      Elf_Internal_Chdr chdr;
-      const struct elf_backend_data *bed = get_elf_backend_data (abfd);
-      if (bed->s->elfclass == ELFCLASS32)
-	{
-	  Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
-	  chdr.ch_type = bfd_get_32 (abfd, &echdr->ch_type);
-	  chdr.ch_size = bfd_get_32 (abfd, &echdr->ch_size);
-	  chdr.ch_addralign = bfd_get_32 (abfd, &echdr->ch_addralign);
-	}
-      else
-	{
-	  Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
-	  chdr.ch_type = bfd_get_32 (abfd, &echdr->ch_type);
-	  chdr.ch_size = bfd_get_64 (abfd, &echdr->ch_size);
-	  chdr.ch_addralign = bfd_get_64 (abfd, &echdr->ch_addralign);
-	}
-      *ch_type = chdr.ch_type;
-      if ((chdr.ch_type == ELFCOMPRESS_ZLIB
-	   || chdr.ch_type == ELFCOMPRESS_ZSTD)
-	  && chdr.ch_addralign == (chdr.ch_addralign & -chdr.ch_addralign))
-	{
-	  *uncompressed_size = chdr.ch_size;
-	  *uncompressed_alignment_power = bfd_log2 (chdr.ch_addralign);
-	  return true;
-	}
-    }
-
-  return false;
-}
-
-/*
-FUNCTION
-	bfd_get_compression_header_size
-
-SYNOPSIS
-	int bfd_get_compression_header_size (bfd *abfd, asection *sec);
-
-DESCRIPTION
-	Return the size of the compression header of SEC in ABFD.
-
-RETURNS
-	Return the size of the compression header in bytes.
-*/
-
-int
-bfd_get_compression_header_size (bfd *abfd, asection *sec)
-{
-  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
-    {
-      if (sec == NULL)
-	{
-	  if (!(abfd->flags & BFD_COMPRESS_GABI))
-	    return 0;
-	}
-      else if (!(elf_section_flags (sec) & SHF_COMPRESSED))
-	return 0;
-
-      if (get_elf_backend_data (abfd)->s->elfclass == ELFCLASS32)
-	return sizeof (Elf32_External_Chdr);
-      else
-	return sizeof (Elf64_External_Chdr);
-    }
-
-  return 0;
-}
-
-/*
-FUNCTION
-	bfd_convert_section_size
-
-SYNOPSIS
-	bfd_size_type bfd_convert_section_size
-	  (bfd *ibfd, asection *isec, bfd *obfd, bfd_size_type size);
-
-DESCRIPTION
-	Convert the size @var{size} of the section @var{isec} in input
-	BFD @var{ibfd} to the section size in output BFD @var{obfd}.
-*/
-
-bfd_size_type
-bfd_convert_section_size (bfd *ibfd, sec_ptr isec, bfd *obfd,
-			  bfd_size_type size)
-{
-  bfd_size_type hdr_size;
-
-  /* Do nothing if either input or output aren't ELF.  */
-  if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
-      || bfd_get_flavour (obfd) != bfd_target_elf_flavour)
-    return size;
-
-  /* Do nothing if ELF classes of input and output are the same. */
-  if (get_elf_backend_data (ibfd)->s->elfclass
-      == get_elf_backend_data (obfd)->s->elfclass)
-    return size;
-
-  /* Convert GNU property size.  */
-  if (startswith (isec->name, NOTE_GNU_PROPERTY_SECTION_NAME))
-    return _bfd_elf_convert_gnu_property_size (ibfd, obfd);
-
-  /* Do nothing if input file will be decompressed.  */
-  if ((ibfd->flags & BFD_DECOMPRESS))
-    return size;
-
-  /* Do nothing if the input section isn't a SHF_COMPRESSED section. */
-  hdr_size = bfd_get_compression_header_size (ibfd, isec);
-  if (hdr_size == 0)
-    return size;
-
-  /* Adjust the size of the output SHF_COMPRESSED section.  */
-  if (hdr_size == sizeof (Elf32_External_Chdr))
-    return (size - sizeof (Elf32_External_Chdr)
-	    + sizeof (Elf64_External_Chdr));
-  else
-    return (size - sizeof (Elf64_External_Chdr)
-	    + sizeof (Elf32_External_Chdr));
-}
-
-/*
-FUNCTION
-	bfd_convert_section_contents
-
-SYNOPSIS
-	bool bfd_convert_section_contents
-	  (bfd *ibfd, asection *isec, bfd *obfd,
-	   bfd_byte **ptr, bfd_size_type *ptr_size);
-
-DESCRIPTION
-	Convert the contents, stored in @var{*ptr}, of the section
-	@var{isec} in input BFD @var{ibfd} to output BFD @var{obfd}
-	if needed.  The original buffer pointed to by @var{*ptr} may
-	be freed and @var{*ptr} is returned with memory malloc'd by this
-	function, and the new size written to @var{ptr_size}.
-*/
-
-bool
-bfd_convert_section_contents (bfd *ibfd, sec_ptr isec, bfd *obfd,
-			      bfd_byte **ptr, bfd_size_type *ptr_size)
-{
-  bfd_byte *contents;
-  bfd_size_type ihdr_size, ohdr_size, size;
-  Elf_Internal_Chdr chdr;
-  bool use_memmove;
-
-  /* Do nothing if either input or output aren't ELF.  */
-  if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
-      || bfd_get_flavour (obfd) != bfd_target_elf_flavour)
-    return true;
-
-  /* Do nothing if ELF classes of input and output are the same.  */
-  if (get_elf_backend_data (ibfd)->s->elfclass
-      == get_elf_backend_data (obfd)->s->elfclass)
-    return true;
-
-  /* Convert GNU properties.  */
-  if (startswith (isec->name, NOTE_GNU_PROPERTY_SECTION_NAME))
-    return _bfd_elf_convert_gnu_properties (ibfd, isec, obfd, ptr,
-					    ptr_size);
-
-  /* Do nothing if input file will be decompressed.  */
-  if ((ibfd->flags & BFD_DECOMPRESS))
-    return true;
-
-  /* Do nothing if the input section isn't a SHF_COMPRESSED section.  */
-  ihdr_size = bfd_get_compression_header_size (ibfd, isec);
-  if (ihdr_size == 0)
-    return true;
-
-  /* PR 25221.  Check for corrupt input sections.  */
-  if (ihdr_size > bfd_get_section_limit (ibfd, isec))
-    /* FIXME: Issue a warning about a corrupt
-       compression header size field ?  */
-    return false;
-
-  contents = *ptr;
-
-  /* Convert the contents of the input SHF_COMPRESSED section to
-     output.  Get the input compression header and the size of the
-     output compression header.  */
-  if (ihdr_size == sizeof (Elf32_External_Chdr))
-    {
-      Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
-      chdr.ch_type = bfd_get_32 (ibfd, &echdr->ch_type);
-      chdr.ch_size = bfd_get_32 (ibfd, &echdr->ch_size);
-      chdr.ch_addralign = bfd_get_32 (ibfd, &echdr->ch_addralign);
-
-      ohdr_size = sizeof (Elf64_External_Chdr);
-
-      use_memmove = false;
-    }
-  else if (ihdr_size != sizeof (Elf64_External_Chdr))
-    {
-      /* FIXME: Issue a warning about a corrupt
-	 compression header size field ?  */
-      return false;
-    }
-  else
-    {
-      Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
-      chdr.ch_type = bfd_get_32 (ibfd, &echdr->ch_type);
-      chdr.ch_size = bfd_get_64 (ibfd, &echdr->ch_size);
-      chdr.ch_addralign = bfd_get_64 (ibfd, &echdr->ch_addralign);
-
-      ohdr_size = sizeof (Elf32_External_Chdr);
-      use_memmove = true;
-    }
-
-  size = bfd_section_size (isec) - ihdr_size + ohdr_size;
-  if (!use_memmove)
-    {
-      contents = (bfd_byte *) bfd_malloc (size);
-      if (contents == NULL)
-	return false;
-    }
-
-  /* Write out the output compression header.  */
-  if (ohdr_size == sizeof (Elf32_External_Chdr))
-    {
-      Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
-      bfd_put_32 (obfd, chdr.ch_type, &echdr->ch_type);
-      bfd_put_32 (obfd, chdr.ch_size, &echdr->ch_size);
-      bfd_put_32 (obfd, chdr.ch_addralign, &echdr->ch_addralign);
-    }
-  else
-    {
-      Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
-      bfd_put_32 (obfd, chdr.ch_type, &echdr->ch_type);
-      bfd_put_32 (obfd, 0, &echdr->ch_reserved);
-      bfd_put_64 (obfd, chdr.ch_size, &echdr->ch_size);
-      bfd_put_64 (obfd, chdr.ch_addralign, &echdr->ch_addralign);
-    }
-
-  /* Copy the compressed contents.  */
-  if (use_memmove)
-    memmove (contents + ohdr_size, *ptr + ihdr_size, size - ohdr_size);
-  else
-    {
-      memcpy (contents + ohdr_size, *ptr + ihdr_size, size - ohdr_size);
-      free (*ptr);
-      *ptr = contents;
-    }
-
-  *ptr_size = size;
-  return true;
-}
-
 /* Get the linker information.  */
 
 struct bfd_link_info *
diff --git a/bfd/compress.c b/bfd/compress.c
index 6b08346..a4e6a8e 100644
--- a/bfd/compress.c
+++ b/bfd/compress.c
@@ -32,6 +32,13 @@
 
 /*
 CODE_FRAGMENT
+.enum compression_type
+.{
+.  ch_none = 0,
+.  ch_compress_zlib = 1	,	{* Compressed with zlib.  *}
+.  ch_compress_zstd = 2		{* Compressed with zstd (www.zstandard.org).  *}
+.};
+.
 .static inline char *
 .bfd_debug_name_to_zdebug (bfd *abfd, const char *name)
 .{
@@ -59,6 +66,342 @@ CODE_FRAGMENT
 .
 */
 
+/*
+FUNCTION
+	bfd_update_compression_header
+
+SYNOPSIS
+	void bfd_update_compression_header
+	  (bfd *abfd, bfd_byte *contents, asection *sec);
+
+DESCRIPTION
+	Set the compression header at CONTENTS of SEC in ABFD and update
+	elf_section_flags for compression.
+*/
+
+void
+bfd_update_compression_header (bfd *abfd, bfd_byte *contents,
+			       asection *sec)
+{
+  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);
+	  struct bfd_elf_section_data * esd = elf_section_data (sec);
+	  enum compression_type ch_type = (abfd->flags & BFD_COMPRESS_ZSTD
+					   ? ch_compress_zstd
+					   : ch_compress_zlib);
+
+	  /* Set the SHF_COMPRESSED bit.  */
+	  elf_section_flags (sec) |= SHF_COMPRESSED;
+
+	  if (bed->s->elfclass == ELFCLASS32)
+	    {
+	      Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
+	      bfd_put_32 (abfd, ch_type, &echdr->ch_type);
+	      bfd_put_32 (abfd, sec->size, &echdr->ch_size);
+	      bfd_put_32 (abfd, 1u << sec->alignment_power,
+			  &echdr->ch_addralign);
+	      /* bfd_log2 (alignof (Elf32_Chdr)) */
+	      bfd_set_section_alignment (sec, 2);
+	      esd->this_hdr.sh_addralign = 4;
+	    }
+	  else
+	    {
+	      Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
+	      bfd_put_32 (abfd, ch_type, &echdr->ch_type);
+	      bfd_put_32 (abfd, 0, &echdr->ch_reserved);
+	      bfd_put_64 (abfd, sec->size, &echdr->ch_size);
+	      bfd_put_64 (abfd, UINT64_C (1) << sec->alignment_power,
+			  &echdr->ch_addralign);
+	      /* bfd_log2 (alignof (Elf64_Chdr)) */
+	      bfd_set_section_alignment (sec, 3);
+	      esd->this_hdr.sh_addralign = 8;
+	    }
+	  break;
+	}
+
+      /* 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.  */
+      memcpy (contents, "ZLIB", 4);
+      bfd_putb64 (sec->size, contents + 4);
+      /* No way to keep the original alignment, just use 1 always. */
+      bfd_set_section_alignment (sec, 0);
+      break;
+    }
+}
+
+/* Check the compression header at CONTENTS of SEC in ABFD and store the
+   ch_type in CH_TYPE, uncompressed size in UNCOMPRESSED_SIZE, and the
+   uncompressed data alignment in UNCOMPRESSED_ALIGNMENT_POWER if the
+   compression header is valid.  */
+
+static bool
+bfd_check_compression_header (bfd *abfd, bfd_byte *contents,
+			      asection *sec,
+			      enum compression_type *ch_type,
+			      bfd_size_type *uncompressed_size,
+			      unsigned int *uncompressed_alignment_power)
+{
+  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour
+      && (elf_section_flags (sec) & SHF_COMPRESSED) != 0)
+    {
+      Elf_Internal_Chdr chdr;
+      const struct elf_backend_data *bed = get_elf_backend_data (abfd);
+      if (bed->s->elfclass == ELFCLASS32)
+	{
+	  Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
+	  chdr.ch_type = bfd_get_32 (abfd, &echdr->ch_type);
+	  chdr.ch_size = bfd_get_32 (abfd, &echdr->ch_size);
+	  chdr.ch_addralign = bfd_get_32 (abfd, &echdr->ch_addralign);
+	}
+      else
+	{
+	  Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
+	  chdr.ch_type = bfd_get_32 (abfd, &echdr->ch_type);
+	  chdr.ch_size = bfd_get_64 (abfd, &echdr->ch_size);
+	  chdr.ch_addralign = bfd_get_64 (abfd, &echdr->ch_addralign);
+	}
+      *ch_type = chdr.ch_type;
+      if ((chdr.ch_type == ch_compress_zlib
+	   || chdr.ch_type == ch_compress_zstd)
+	  && chdr.ch_addralign == (chdr.ch_addralign & -chdr.ch_addralign))
+	{
+	  *uncompressed_size = chdr.ch_size;
+	  *uncompressed_alignment_power = bfd_log2 (chdr.ch_addralign);
+	  return true;
+	}
+    }
+
+  return false;
+}
+
+/*
+FUNCTION
+	bfd_get_compression_header_size
+
+SYNOPSIS
+	int bfd_get_compression_header_size (bfd *abfd, asection *sec);
+
+DESCRIPTION
+	Return the size of the compression header of SEC in ABFD.
+
+RETURNS
+	Return the size of the compression header in bytes.
+*/
+
+int
+bfd_get_compression_header_size (bfd *abfd, asection *sec)
+{
+  if (bfd_get_flavour (abfd) == bfd_target_elf_flavour)
+    {
+      if (sec == NULL)
+	{
+	  if (!(abfd->flags & BFD_COMPRESS_GABI))
+	    return 0;
+	}
+      else if (!(elf_section_flags (sec) & SHF_COMPRESSED))
+	return 0;
+
+      if (get_elf_backend_data (abfd)->s->elfclass == ELFCLASS32)
+	return sizeof (Elf32_External_Chdr);
+      else
+	return sizeof (Elf64_External_Chdr);
+    }
+
+  return 0;
+}
+
+/*
+FUNCTION
+	bfd_convert_section_size
+
+SYNOPSIS
+	bfd_size_type bfd_convert_section_size
+	  (bfd *ibfd, asection *isec, bfd *obfd, bfd_size_type size);
+
+DESCRIPTION
+	Convert the size @var{size} of the section @var{isec} in input
+	BFD @var{ibfd} to the section size in output BFD @var{obfd}.
+*/
+
+bfd_size_type
+bfd_convert_section_size (bfd *ibfd, sec_ptr isec, bfd *obfd,
+			  bfd_size_type size)
+{
+  bfd_size_type hdr_size;
+
+  /* Do nothing if either input or output aren't ELF.  */
+  if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
+      || bfd_get_flavour (obfd) != bfd_target_elf_flavour)
+    return size;
+
+  /* Do nothing if ELF classes of input and output are the same. */
+  if (get_elf_backend_data (ibfd)->s->elfclass
+      == get_elf_backend_data (obfd)->s->elfclass)
+    return size;
+
+  /* Convert GNU property size.  */
+  if (startswith (isec->name, NOTE_GNU_PROPERTY_SECTION_NAME))
+    return _bfd_elf_convert_gnu_property_size (ibfd, obfd);
+
+  /* Do nothing if input file will be decompressed.  */
+  if ((ibfd->flags & BFD_DECOMPRESS))
+    return size;
+
+  /* Do nothing if the input section isn't a SHF_COMPRESSED section. */
+  hdr_size = bfd_get_compression_header_size (ibfd, isec);
+  if (hdr_size == 0)
+    return size;
+
+  /* Adjust the size of the output SHF_COMPRESSED section.  */
+  if (hdr_size == sizeof (Elf32_External_Chdr))
+    return (size - sizeof (Elf32_External_Chdr)
+	    + sizeof (Elf64_External_Chdr));
+  else
+    return (size - sizeof (Elf64_External_Chdr)
+	    + sizeof (Elf32_External_Chdr));
+}
+
+/*
+FUNCTION
+	bfd_convert_section_contents
+
+SYNOPSIS
+	bool bfd_convert_section_contents
+	  (bfd *ibfd, asection *isec, bfd *obfd,
+	   bfd_byte **ptr, bfd_size_type *ptr_size);
+
+DESCRIPTION
+	Convert the contents, stored in @var{*ptr}, of the section
+	@var{isec} in input BFD @var{ibfd} to output BFD @var{obfd}
+	if needed.  The original buffer pointed to by @var{*ptr} may
+	be freed and @var{*ptr} is returned with memory malloc'd by this
+	function, and the new size written to @var{ptr_size}.
+*/
+
+bool
+bfd_convert_section_contents (bfd *ibfd, sec_ptr isec, bfd *obfd,
+			      bfd_byte **ptr, bfd_size_type *ptr_size)
+{
+  bfd_byte *contents;
+  bfd_size_type ihdr_size, ohdr_size, size;
+  Elf_Internal_Chdr chdr;
+  bool use_memmove;
+
+  /* Do nothing if either input or output aren't ELF.  */
+  if (bfd_get_flavour (ibfd) != bfd_target_elf_flavour
+      || bfd_get_flavour (obfd) != bfd_target_elf_flavour)
+    return true;
+
+  /* Do nothing if ELF classes of input and output are the same.  */
+  if (get_elf_backend_data (ibfd)->s->elfclass
+      == get_elf_backend_data (obfd)->s->elfclass)
+    return true;
+
+  /* Convert GNU properties.  */
+  if (startswith (isec->name, NOTE_GNU_PROPERTY_SECTION_NAME))
+    return _bfd_elf_convert_gnu_properties (ibfd, isec, obfd, ptr,
+					    ptr_size);
+
+  /* Do nothing if input file will be decompressed.  */
+  if ((ibfd->flags & BFD_DECOMPRESS))
+    return true;
+
+  /* Do nothing if the input section isn't a SHF_COMPRESSED section.  */
+  ihdr_size = bfd_get_compression_header_size (ibfd, isec);
+  if (ihdr_size == 0)
+    return true;
+
+  /* PR 25221.  Check for corrupt input sections.  */
+  if (ihdr_size > bfd_get_section_limit (ibfd, isec))
+    /* FIXME: Issue a warning about a corrupt
+       compression header size field ?  */
+    return false;
+
+  contents = *ptr;
+
+  /* Convert the contents of the input SHF_COMPRESSED section to
+     output.  Get the input compression header and the size of the
+     output compression header.  */
+  if (ihdr_size == sizeof (Elf32_External_Chdr))
+    {
+      Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
+      chdr.ch_type = bfd_get_32 (ibfd, &echdr->ch_type);
+      chdr.ch_size = bfd_get_32 (ibfd, &echdr->ch_size);
+      chdr.ch_addralign = bfd_get_32 (ibfd, &echdr->ch_addralign);
+
+      ohdr_size = sizeof (Elf64_External_Chdr);
+
+      use_memmove = false;
+    }
+  else if (ihdr_size != sizeof (Elf64_External_Chdr))
+    {
+      /* FIXME: Issue a warning about a corrupt
+	 compression header size field ?  */
+      return false;
+    }
+  else
+    {
+      Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
+      chdr.ch_type = bfd_get_32 (ibfd, &echdr->ch_type);
+      chdr.ch_size = bfd_get_64 (ibfd, &echdr->ch_size);
+      chdr.ch_addralign = bfd_get_64 (ibfd, &echdr->ch_addralign);
+
+      ohdr_size = sizeof (Elf32_External_Chdr);
+      use_memmove = true;
+    }
+
+  size = bfd_section_size (isec) - ihdr_size + ohdr_size;
+  if (!use_memmove)
+    {
+      contents = (bfd_byte *) bfd_malloc (size);
+      if (contents == NULL)
+	return false;
+    }
+
+  /* Write out the output compression header.  */
+  if (ohdr_size == sizeof (Elf32_External_Chdr))
+    {
+      Elf32_External_Chdr *echdr = (Elf32_External_Chdr *) contents;
+      bfd_put_32 (obfd, chdr.ch_type, &echdr->ch_type);
+      bfd_put_32 (obfd, chdr.ch_size, &echdr->ch_size);
+      bfd_put_32 (obfd, chdr.ch_addralign, &echdr->ch_addralign);
+    }
+  else
+    {
+      Elf64_External_Chdr *echdr = (Elf64_External_Chdr *) contents;
+      bfd_put_32 (obfd, chdr.ch_type, &echdr->ch_type);
+      bfd_put_32 (obfd, 0, &echdr->ch_reserved);
+      bfd_put_64 (obfd, chdr.ch_size, &echdr->ch_size);
+      bfd_put_64 (obfd, chdr.ch_addralign, &echdr->ch_addralign);
+    }
+
+  /* Copy the compressed contents.  */
+  if (use_memmove)
+    memmove (contents + ohdr_size, *ptr + ihdr_size, size - ohdr_size);
+  else
+    {
+      memcpy (contents + ohdr_size, *ptr + ihdr_size, size - ohdr_size);
+      free (*ptr);
+      *ptr = contents;
+    }
+
+  *ptr_size = size;
+  return true;
+}
+
 static bool
 decompress_contents (bool is_zstd, bfd_byte *compressed_buffer,
 		     bfd_size_type compressed_size,
@@ -128,7 +471,7 @@ bfd_compress_section_contents (bfd *abfd, sec_ptr sec)
   int orig_header_size;
   bfd_size_type uncompressed_size;
   unsigned int uncompressed_alignment_pow;
-  unsigned int ch_type = 0;
+  enum compression_type ch_type = ch_none;
   int new_header_size = bfd_get_compression_header_size (abfd, NULL);
   bool compressed
     = bfd_is_section_compressed_info (abfd, sec,
@@ -146,7 +489,7 @@ bfd_compress_section_contents (bfd *abfd, sec_ptr sec)
      overhead in .zdebug* section.  */
   if (!new_header_size)
     new_header_size = 12;
-  if (ch_type == 0)
+  if (ch_type == ch_none)
     orig_header_size = 12;
 
   input_buffer = sec->contents;
@@ -157,7 +500,7 @@ bfd_compress_section_contents (bfd *abfd, sec_ptr sec)
 
       /* If we are converting between zlib-gnu and zlib-gabi then the
 	 compressed contents just need to be moved.  */
-      update = (ch_type < ELFCOMPRESS_ZSTD
+      update = (ch_type < ch_compress_zstd
 		&& (abfd->flags & BFD_COMPRESS_ZSTD) == 0);
 
       /* Uncompress when not just moving contents or when compressed
@@ -169,7 +512,7 @@ bfd_compress_section_contents (bfd *abfd, sec_ptr sec)
 	  if (buffer == NULL)
 	    return 0;
 
-	  if (!decompress_contents (ch_type == ELFCOMPRESS_ZSTD,
+	  if (!decompress_contents (ch_type == ch_compress_zstd,
 				    input_buffer + orig_header_size,
 				    zlib_size, buffer, buffer_size))
 	    {
@@ -408,7 +751,7 @@ SYNOPSIS
 	   int *compression_header_size_p,
 	   bfd_size_type *uncompressed_size_p,
 	   unsigned int *uncompressed_alignment_power_p,
-	   unsigned int *ch_type);
+	   enum compression_type *ch_type);
 
 DESCRIPTION
 	Return @code{TRUE} if @var{section} is compressed.  Compression
@@ -425,7 +768,7 @@ bfd_is_section_compressed_info (bfd *abfd, sec_ptr sec,
 				int *compression_header_size_p,
 				bfd_size_type *uncompressed_size_p,
 				unsigned int *uncompressed_align_pow_p,
-				unsigned int *ch_type)
+				enum compression_type *ch_type)
 {
   bfd_byte header[MAX_COMPRESSION_HEADER_SIZE];
   int compression_header_size;
@@ -501,7 +844,7 @@ bfd_is_section_compressed (bfd *abfd, sec_ptr sec)
   int compression_header_size;
   bfd_size_type uncompressed_size;
   unsigned int uncompressed_align_power;
-  unsigned int ch_type;
+  enum compression_type ch_type;
   return (bfd_is_section_compressed_info (abfd, sec,
 					  &compression_header_size,
 					  &uncompressed_size,
@@ -536,7 +879,7 @@ bfd_init_section_decompress_status (bfd *abfd, sec_ptr sec)
   int header_size;
   bfd_size_type uncompressed_size;
   unsigned int uncompressed_alignment_power = 0;
-  unsigned int ch_type;
+  enum compression_type ch_type;
   z_stream strm;
 
   compression_header_size = bfd_get_compression_header_size (abfd, sec);
@@ -564,7 +907,7 @@ bfd_init_section_decompress_status (bfd *abfd, sec_ptr sec)
 	  return false;
 	}
       uncompressed_size = bfd_getb64 (header + 4);
-      ch_type = 0;
+      ch_type = ch_none;
     }
   else if (!bfd_check_compression_header (abfd, header, sec,
 					  &ch_type,
@@ -587,7 +930,7 @@ bfd_init_section_decompress_status (bfd *abfd, sec_ptr sec)
   sec->compressed_size = sec->size;
   sec->size = uncompressed_size;
   bfd_set_section_alignment (sec, uncompressed_alignment_power);
-  sec->compress_status = (ch_type == ELFCOMPRESS_ZSTD
+  sec->compress_status = (ch_type == ch_compress_zstd
 			  ? DECOMPRESS_SECTION_ZSTD : DECOMPRESS_SECTION_ZLIB);
 
   return true;
diff --git a/bfd/elf.c b/bfd/elf.c
index 9e490c9..a013f88 100644
--- a/bfd/elf.c
+++ b/bfd/elf.c
@@ -1184,7 +1184,7 @@ _bfd_elf_make_section_from_shdr (bfd *abfd,
       int compression_header_size;
       bfd_size_type uncompressed_size;
       unsigned int uncompressed_align_power;
-      unsigned int ch_type = 0;
+      enum compression_type ch_type = ch_none;
       bool compressed
 	= bfd_is_section_compressed_info (abfd, newsect,
 					  &compression_header_size,
@@ -1206,10 +1206,10 @@ _bfd_elf_make_section_from_shdr (bfd *abfd,
 	    action = compress;
 	  else
 	    {
-	      unsigned int new_ch_type = 0;
+	      enum compression_type new_ch_type = ch_none;
 	      if ((abfd->flags & BFD_COMPRESS_GABI) != 0)
 		new_ch_type = ((abfd->flags & BFD_COMPRESS_ZSTD) != 0
-			       ? ELFCOMPRESS_ZSTD : ELFCOMPRESS_ZLIB);
+			       ? ch_compress_zstd : ch_compress_zlib);
 	      if (new_ch_type != ch_type)
 		action = compress;
 	    }
diff --git a/binutils/readelf.c b/binutils/readelf.c
index 1bd6df9..bce9378 100644
--- a/binutils/readelf.c
+++ b/binutils/readelf.c
@@ -7803,9 +7803,9 @@ process_section_headers (Filedata * filedata)
 		    printf (_("       [<corrupt>]\n"));
 		  else
 		    {
-		      if (chdr.ch_type == ELFCOMPRESS_ZLIB)
+		      if (chdr.ch_type == ch_compress_zlib)
 			printf ("       ZLIB, ");
-		      else if (chdr.ch_type == ELFCOMPRESS_ZSTD)
+		      else if (chdr.ch_type == ch_compress_zstd)
 			printf ("       ZSTD, ");
 		      else
 			printf (_("       [<unknown>: 0x%x], "),
@@ -15369,10 +15369,10 @@ dump_section_as_strings (Elf_Internal_Shdr * section, Filedata * filedata)
 	       by get_compression_header.  */
 	    goto error_out;
 
-	  if (chdr.ch_type == ELFCOMPRESS_ZLIB)
+	  if (chdr.ch_type == ch_compress_zlib)
 	    ;
 #ifdef HAVE_ZSTD
-	  else if (chdr.ch_type == ELFCOMPRESS_ZSTD)
+	  else if (chdr.ch_type == ch_compress_zstd)
 	    is_zstd = true;
 #endif
 	  else
@@ -15592,10 +15592,10 @@ dump_section_as_bytes (Elf_Internal_Shdr *section,
 	       by get_compression_header.  */
 	    goto error_out;
 
-	  if (chdr.ch_type == ELFCOMPRESS_ZLIB)
+	  if (chdr.ch_type == ch_compress_zlib)
 	    ;
 #ifdef HAVE_ZSTD
-	  else if (chdr.ch_type == ELFCOMPRESS_ZSTD)
+	  else if (chdr.ch_type == ch_compress_zstd)
 	    is_zstd = true;
 #endif
 	  else
@@ -16024,10 +16024,10 @@ load_specific_debug_section (enum dwarf_section_display_enum  debug,
 	       by get_compression_header.  */
 	    return false;
 
-	  if (chdr.ch_type == ELFCOMPRESS_ZLIB)
+	  if (chdr.ch_type == ch_compress_zlib)
 	    ;
 #ifdef HAVE_ZSTD
-	  else if (chdr.ch_type == ELFCOMPRESS_ZSTD)
+	  else if (chdr.ch_type == ch_compress_zstd)
 	    is_zstd = true;
 #endif
 	  else