PR22458, failure to choose a matching ELF target

https://sourceware.org/ml/binutils/2013-05/msg00271.html was supposed
to banish "file format is ambiguous" errors for ELF.  It didn't,
because the code supposedly detecting formats that implement
match_priority didn't work.  That was due to not placing all matching
targets into the vector of matching targets.  ELF objects should all
match the generic ELF target (priority 2), plus one or more machine
specific targets (priority 1), and perhaps a single machine specific
target with OS/ABI set (priority 0, best match).  So the armel object
in the testcase actually matches elf32-littlearm,
elf32-littlearm-symbian, and elf32-littlearm-vxworks (all priority 1),
and elf32-little (priority 2).  As the PR reported, elf32-little
wasn't seen as matching.  Fixing that part of the problem wasn't too
difficult but matching the generic ELF target as well as the ARM ELF
targets resulted in ARM testsuite failures.

These proved to be the annoying reordering of stubs that occurs from
time to time due to the stub names containing the section id.
Matching another target causes more sections to be created in
elf_object_p.  If section ids change, stub names change, which results
in different hashing and can therefore result in different hash table
traversal and stub creation order.  That particular problem is fixed
by resetting section_id to the initial state before attempting each
target match, and taking a snapshot of its value after a successful
match.

	PR 22458
	* format.c (struct bfd_preserve): Add section_id.
	(bfd_preserve_save, bfd_preserve_restore): Save and restore
	_bfd_section_id.
	(bfd_reinit): Set _bfd_section_id.
	(bfd_check_format_matches): Put all matches of any priority into
	matching_vector.  Save initial section id and start each attempted
	match at that section id.
	* libbfd-in.h (_bfd_section_id): Declare.
	* section.c (_bfd_section_id): Rename from section_id and make
	global.  Adjust uses.
	(bfd_get_next_section_id): Delete.
	* elf64-ppc.c (ppc64_elf_setup_section_lists): Replace use of
	bfd_get_section_id with _bfd_section_id.
	* libbfd.h: Regenerate.
	* bfd-in2.h: Regenerate.

1 files changed, 3 insertions, 20 deletions

diff --git a/bfd/section.c b/bfd/section.c
index 752f291..7ee3f69 100644
--- a/bfd/section.c
+++ b/bfd/section.c
@@ -820,21 +820,21 @@ _bfd_generic_new_section_hook (bfd *abfd, asection *newsect)
   return TRUE;
 }
 
-static unsigned int section_id = 0x10;  /* id 0 to 3 used by STD_SECTION.  */
+unsigned int _bfd_section_id = 0x10;  /* id 0 to 3 used by STD_SECTION.  */
 
 /* Initializes a new section.  NEWSECT->NAME is already set.  */
 
 static asection *
 bfd_section_init (bfd *abfd, asection *newsect)
 {
-  newsect->id = section_id;
+  newsect->id = _bfd_section_id;
   newsect->index = abfd->section_count;
   newsect->owner = abfd;
 
   if (! BFD_SEND (abfd, _new_section_hook, (abfd, newsect)))
     return NULL;
 
-  section_id++;
+  _bfd_section_id++;
   abfd->section_count++;
   bfd_section_list_append (abfd, newsect);
   return newsect;
@@ -1286,23 +1286,6 @@ bfd_make_section (bfd *abfd, const char *name)
 
 /*
 FUNCTION
-	bfd_get_next_section_id
-
-SYNOPSIS
-	int bfd_get_next_section_id (void);
-
-DESCRIPTION
-	Returns the id that the next section created will have.
-*/
-
-int
-bfd_get_next_section_id (void)
-{
-  return section_id;
-}
-
-/*
-FUNCTION
 	bfd_set_section_flags
 
 SYNOPSIS