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, 20 insertions, 0 deletions

diff --git a/bfd/elf-bfd.h b/bfd/elf-bfd.h
index 29283f2..01e0da1 100644
--- a/bfd/elf-bfd.h
+++ b/bfd/elf-bfd.h
@@ -1778,6 +1778,12 @@ struct elf_backend_data
   /* True if the 64-bit Linux PRPSINFO structure's `pr_uid' and `pr_gid'
      members use a 16-bit data type.  */
   unsigned linux_prpsinfo64_ugid16 : 1;
+
+  /* True if the backend can use mmap to map in all input section
+     contents.  All bfd_malloc_and_get_section and free usages on
+     section contents must be replaced by _bfd_elf_mmap_section_contents
+     and _bfd_elf_munmap_section_contents.  */
+  unsigned use_mmap : 1;
 };
 
 /* Information about reloc sections associated with a bfd_elf_section_data
@@ -1859,6 +1865,15 @@ struct bfd_elf_section_data
   /* Link from a text section to its .eh_frame_entry section.  */
   asection *eh_frame_entry;
 
+  /* If the mmapped_p flag is set, this points to the actual mmapped
+     address of contents.  If it is set to NULL, contents isn't
+     mmapped.  */
+  void *contents_addr;
+
+  /* If the mmapped_p flag is set, this is the actual mmapped size of
+     contents.  */
+  size_t contents_size;
+
   /* TRUE if the section has secondary reloc sections associated with it.
      FIXME: In the future it might be better to change this into a list
      of secondary reloc sections, making lookup easier and faster.  */
@@ -3127,6 +3142,11 @@ extern bool _bfd_elf_maybe_set_textrel
 extern bool _bfd_elf_add_dynamic_tags
   (bfd *, struct bfd_link_info *, bool);
 
+extern bool _bfd_elf_mmap_section_contents
+  (bfd *abfd, asection *section, bfd_byte **buf);
+extern void _bfd_elf_munmap_section_contents
+  (asection *, void *);
+
 /* Large common section.  */
 extern asection _bfd_elf_large_com_section;