commit f9fc50c3eced243c0648fb0fbfe2c9877c25e1e4
Author: Mark Wielaard <mjw@redhat.com>
Date:   Wed Jul 29 17:51:27 2015 +0200

    unstrip: Handle debuginfo files with missing SHF_INFO_LINK section flags.
    
    With GCC 5 there might be a .rela.plt section with SHF_INFO_LINK set.
    Buggy binutils objdump might strip it from the section in the debug file.
    Ignore such differences for relocation sections and put the flag back
    if necessary.
    
    Also improve the error message a little by only discarding the already
    matched sections if there is an prelink undo section. Otherwise we will
    report all sections as not matching if the file wasn't prelinked instead
    of just the non-matching sections.
    
    New testfiles generated by gcc5 and binutils objdump added.
    
    Signed-off-by: Mark Wielaard <mjw@redhat.com>

diff --git a/src/unstrip.c b/src/unstrip.c
index 4a8e5fa..8833094 100644
--- a/src/unstrip.c
+++ b/src/unstrip.c
@@ -867,12 +867,28 @@ compare_symbols_output (const void *a, const void *b)
 
 #undef CMP
 
+/* Return true if the flags of the sections match, ignoring the SHF_INFO_LINK
+   flag if the section contains relocation information.  */
+static bool
+sections_flags_match (Elf64_Xword sh_flags1, Elf64_Xword sh_flags2,
+		      Elf64_Word sh_type)
+{
+  if (sh_type == SHT_REL || sh_type == SHT_RELA)
+    {
+      sh_flags1 &= ~SHF_INFO_LINK;
+      sh_flags2 &= ~SHF_INFO_LINK;
+    }
+
+  return sh_flags1 == sh_flags2;
+}
+
 /* Return true iff the flags, size, and name match.  */
 static bool
 sections_match (const struct section *sections, size_t i,
 		const GElf_Shdr *shdr, const char *name)
 {
-  return (sections[i].shdr.sh_flags == shdr->sh_flags
+  return (sections_flags_match (sections[i].shdr.sh_flags, shdr->sh_flags,
+				sections[i].shdr.sh_type)
 	  && (sections[i].shdr.sh_size == shdr->sh_size
 	      || (sections[i].shdr.sh_size < shdr->sh_size
 		  && section_can_shrink (&sections[i].shdr)))
@@ -930,10 +946,6 @@ find_alloc_sections_prelink (Elf *debug, Elf_Data *debug_shstrtab,
 			     struct section *sections,
 			     size_t nalloc, size_t nsections)
 {
-  /* Clear assignments that might have been bogus.  */
-  for (size_t i = 0; i < nalloc; ++i)
-    sections[i].outscn = NULL;
-
   Elf_Scn *undo = NULL;
   for (size_t i = nalloc; i < nsections; ++i)
     {
@@ -952,6 +964,10 @@ find_alloc_sections_prelink (Elf *debug, Elf_Data *debug_shstrtab,
   size_t undo_nalloc = 0;
   if (undo != NULL)
     {
+      /* Clear assignments that might have been bogus.  */
+      for (size_t i = 0; i < nalloc; ++i)
+	sections[i].outscn = NULL;
+
       Elf_Data *undodata = elf_rawdata (undo, NULL);
       ELF_CHECK (undodata != NULL,
 		 _("cannot read '.gnu.prelink_undo' section: %s"));
@@ -1500,6 +1516,14 @@ more sections in stripped file than debug file -- arguments reversed?"));
 	shdr_mem.sh_size = sec->shdr.sh_size;
 	shdr_mem.sh_info = sec->shdr.sh_info;
 	shdr_mem.sh_link = sec->shdr.sh_link;
+
+	/* Buggy binutils objdump might have stripped the SHF_INFO_LINK
+	   put it back if necessary.  */
+	if ((sec->shdr.sh_type == SHT_REL || sec->shdr.sh_type == SHT_RELA)
+	    && sec->shdr.sh_flags != shdr_mem.sh_flags
+	    && (sec->shdr.sh_flags & SHF_INFO_LINK) != 0)
+	  shdr_mem.sh_flags |= SHF_INFO_LINK;
+
 	if (sec->shdr.sh_link != SHN_UNDEF)
 	  shdr_mem.sh_link = ndx_section[sec->shdr.sh_link - 1];
 	if (shdr_mem.sh_flags & SHF_INFO_LINK)