elf: Add _bfd_elf_m[un]map_section_contents

Add _bfd_elf_mmap_section_contents and _bfd_elf_munmap_section_contents.
A backend must opt-in to use mmap.  It should replace

bfd_malloc_and_get_section -> _bfd_elf_mmap_section_contents
free			   -> _bfd_elf_munmap_section_contents

on section contents.

	* compress.c (bfd_get_full_section_contents): Don't allocate
	buffer if mmapped_p is true.
	* elf-bfd.h (elf_backend_data): Add use_mmap.
	(bfd_elf_section_data): Add contents_addr and contents_size.
	(_bfd_elf_mmap_section_contents): New.
	(_bfd_elf_munmap_section_contents): Likewise.
	* elf-eh-frame.c (_bfd_elf_parse_eh_frame): Replace
	bfd_malloc_and_get_section and free with
	_bfd_elf_mmap_section_contents and _bfd_elf_munmap_section_contents
	on section contents.
	* elf-sframe.c (_bfd_elf_parse_sframe): Likewise.
	* elf.c (_bfd_elf_make_section_from_shdr): Replace
	bfd_malloc_and_get_section and free with
	_bfd_elf_mmap_section_contents and _bfd_elf_munmap_section_contents
	on section contents.
	(_bfd_elf_print_private_bfd_data): Likewise.
	(_bfd_elf_mmap_section_contents): New.
	(_bfd_elf_munmap_section_contents): Likewise.
	* elf32-i386.c (elf_i386_scan_relocs): Replace
	bfd_malloc_and_get_section and free with
	_bfd_elf_mmap_section_contents and _bfd_elf_munmap_section_contents
	on section contents.
	* elf64-x86-64.c (elf_x86_64_scan_relocs): Likewise.
	(elf_x86_64_get_synthetic_symtab): Likewise.
	* elfcode.h (elf_checksum_contents): Likewise.
	* elflink.c (elf_link_add_object_symbols): Likewise.
	(bfd_elf_get_bfd_needed_list): Likewise.
	* elfxx-target.h (elf_backend_use_mmap): New.
	(elfNN_bed): Add elf_backend_use_mmap.
	* elfxx-x86.c (elf_x86_size_or_finish_relative_reloc): Replace
	bfd_malloc_and_get_section and free with
	_bfd_elf_mmap_section_contents and _bfd_elf_munmap_section_contents
	on section contents.
	(_bfd_x86_elf_get_synthetic_symtab): Replace free with
	_bfd_elf_munmap_section_contents.
	* elfxx-x86.h (elf_backend_use_mmap): New.
	* libbfd.c: Include "elf-bfd.h".
	(_bfd_generic_get_section_contents): Call bfd_mmap_local for
	mmapped_p.
	* opncls.c (_bfd_delete_bfd): Also munmap ELF section contents.
	* section.c (asection): Add mmapped_p.
	(BFD_FAKE_SECTION): Updated.
	(bfd_malloc_and_get_section): Add a sanity check for not
	mmapped_p.
	* bfd-in2.h: Regenerated.

1 files changed, 3 insertions, 4 deletions

diff --git a/bfd/elfcode.h b/bfd/elfcode.h
index 1e07846..39dfe0b 100644
--- a/bfd/elfcode.h
+++ b/bfd/elfcode.h
@@ -1195,6 +1195,7 @@ elf_checksum_contents (bfd *abfd,
       Elf_Internal_Shdr i_shdr;
       Elf_External_Shdr x_shdr;
       bfd_byte *contents, *free_contents;
+      asection *sec = NULL;
 
       i_shdr = *i_shdrp[count];
       i_shdr.sh_offset = 0;
@@ -1210,8 +1211,6 @@ elf_checksum_contents (bfd *abfd,
       contents = i_shdr.contents;
       if (contents == NULL)
 	{
-	  asection *sec;
-
 	  sec = bfd_section_from_elf_index (abfd, count);
 	  if (sec != NULL)
 	    {
@@ -1220,7 +1219,7 @@ elf_checksum_contents (bfd *abfd,
 		{
 		  /* Force rereading from file.  */
 		  sec->flags &= ~SEC_IN_MEMORY;
-		  if (!bfd_malloc_and_get_section (abfd, sec, &free_contents))
+		  if (!_bfd_elf_mmap_section_contents (abfd, sec, &free_contents))
 		    continue;
 		  contents = free_contents;
 		}
@@ -1229,7 +1228,7 @@ elf_checksum_contents (bfd *abfd,
       if (contents != NULL)
 	{
 	  (*process) (contents, i_shdr.sh_size, arg);
-	  free (free_contents);
+	  _bfd_elf_munmap_section_contents (sec, free_contents);
 	}
     }