Adjust compare_link_order for unstable qsort

In a cross toolchain for nios2-elf target and x86_64-w64-mingw32 host
using binutils 2.37, we observed a failure that didn't show up on
x86_64-linux-gnu host:  testcase pr25490-5.s was failing with

C:\path\to\nios2-elf-ld.exe: looping in map_segments
FAIL: __patchable_function_entries section 5

    	* ldelfgen.c (compare_link_order): Don't use section id in
	sorting.  Keep original ordering instead.  Update comments.

diff --git a/ld/ldelfgen.c b/ld/ldelfgen.c
index c456d4751e166b55ee59004130bdfe672a9a7a6e..d86515a4892166d68603d240a3a37d2561ba006d 100644 (file)
--- a/ld/ldelfgen.c
+++ b/ld/ldelfgen.c
@@ -173,8 +173,9 @@ compare_link_order (const void *a, const void *b)
 
   if (! bfd_link_relocatable (&link_info))
     {
-      /* The only way we should get matching LMAs is when
-        the first of the two sections has zero size.  */
+      /* The only way we should get matching LMAs is when the first of
+        the two sections has zero size, or asec and bsec are the
+        same section.  */
       if (asec->size < bsec->size)
        return -1;
       else if (asec->size > bsec->size)
@@ -183,7 +184,7 @@ compare_link_order (const void *a, const void *b)
 
   /* If they are both zero size then they almost certainly have the same
      VMA and thus are not ordered with respect to each other.  Test VMA
-     anyway, and fall back to id to make the result reproducible across
+     anyway, and fall back to idx to make the result reproducible across
      qsort implementations.  */
   apos = asec->output_section->vma + asec->output_offset;
   bpos = bsec->output_section->vma + bsec->output_offset;
@@ -191,8 +192,8 @@ compare_link_order (const void *a, const void *b)
     return -1;
   else if (apos > bpos)
     return 1;
-
-  return asec->id - bsec->id;
+  else
+    return ai->idx - bi->idx;
 }
 
 /* Rearrange sections with SHF_LINK_ORDER into the same order as their