PR 19264 looping in ppc64_elf_size_stubs

b399102 fixed the testcase in this PR but it may be possible to
trigger the problem in other ways.

	PR ld/19264
	* elf64-ppc.c (STUB_SHRINK_ITER): Define.
	(ppc64_elf_size_stubs): Exit stub sizing loop past STUB_SHRINK_ITER
	if shrinking stubs.
	(ppc64_elf_size_stubs): Adjust to suit.

diff --git a/bfd/ChangeLog b/bfd/ChangeLog
index 6fb242c..bf95751 100644 (file)
--- a/bfd/ChangeLog
+++ b/bfd/ChangeLog
@@ -1,3 +1,11 @@
+2016-06-27  Alan Modra  <amodra@gmail.com>
+
+       PR ld/19264
+       * elf64-ppc.c (STUB_SHRINK_ITER): Define.
+       (ppc64_elf_size_stubs): Exit stub sizing loop past STUB_SHRINK_ITER
+       if shrinking stubs.
+       (ppc64_elf_size_stubs): Adjust to suit.
+
 2016-06-27  Trevor Saunders  <tbsaunde+binutils@tbsaunde.org>
 
        * elf32-dlx.h: New file.

diff --git a/bfd/elf64-ppc.c b/bfd/elf64-ppc.c
index 70fa5c3..e06b576 100644 (file)
--- a/bfd/elf64-ppc.c
+++ b/bfd/elf64-ppc.c
@@ -12185,6 +12185,13 @@ ppc64_elf_size_stubs (struct bfd_link_info *info)
   if (!group_sections (info, stub_group_size, stubs_always_before_branch))
     return FALSE;
 
+#define STUB_SHRINK_ITER 20
+  /* Loop until no stubs added.  After iteration 20 of this loop we may
+     exit on a stub section shrinking.  This is to break out of a
+     pathological case where adding stubs on one iteration decreases
+     section gaps (perhaps due to alignment), which then requires
+     fewer or smaller stubs on the next iteration.  */
+
   while (1)
     {
       bfd *input_bfd;
@@ -12566,11 +12573,11 @@ ppc64_elf_size_stubs (struct bfd_link_info *info)
           stub_sec != NULL;
           stub_sec = stub_sec->next)
        if ((stub_sec->flags & SEC_LINKER_CREATED) == 0
-           && stub_sec->rawsize != stub_sec->size)
+           && stub_sec->rawsize != stub_sec->size
+           && (htab->stub_iteration <= STUB_SHRINK_ITER
+               || stub_sec->rawsize < stub_sec->size))
          break;
 
-      /* Exit from this loop when no stubs have been added, and no stubs
-        have changed size.  */
       if (stub_sec == NULL
          && (htab->glink_eh_frame == NULL
              || htab->glink_eh_frame->rawsize == htab->glink_eh_frame->size))
@@ -12901,9 +12908,6 @@ ppc64_elf_build_stubs (struct bfd_link_info *info,
        stub_sec->contents = bfd_zalloc (htab->params->stub_bfd, stub_sec->size);
        if (stub_sec->contents == NULL)
          return FALSE;
-       /* We want to check that built size is the same as calculated
-          size.  rawsize is a convenient location to use.  */
-       stub_sec->rawsize = stub_sec->size;
        stub_sec->size = 0;
       }
 
@@ -13092,7 +13096,9 @@ ppc64_elf_build_stubs (struct bfd_link_info *info,
     if ((stub_sec->flags & SEC_LINKER_CREATED) == 0)
       {
        stub_sec_count += 1;
-       if (stub_sec->rawsize != stub_sec->size)
+       if (stub_sec->rawsize != stub_sec->size
+           && (htab->stub_iteration <= STUB_SHRINK_ITER
+               || stub_sec->rawsize < stub_sec->size))
          break;
       }