PR28149, debug info with wrong file association

[Alan Modra]

Linaro TCWG CI sent me a love letter.  :)

Fixes segfaults when building aarch64-linux kernel, due to only doing
part of the work necessary when allocating file numbers late.  I'd
missed looping over subsegments, which resulted in some u.filename
entries left around and later interpreted as u.view.

	PR 28149
	* dwarf2dbg.c (purge_generated_debug): Iterate over subsegs too.
	(dwarf2_finish): Call do_allocate_filenum for all subsegs too,
	in a separate loop before subsegs are chained.

diff --git a/gas/dwarf2dbg.c b/gas/dwarf2dbg.c
index 1250fcef54f..e2abe19c88a 100644
--- a/gas/dwarf2dbg.c
+++ b/gas/dwarf2dbg.c
@@ -792,19 +792,23 @@ purge_generated_debug (void)
 
   for (s = all_segs; s; s = s->next)
     {
-      struct line_subseg *lss = s->head;
-      struct line_entry *e, *next;
+      struct line_subseg *lss;
 
-      for (e = lss->head; e; e = next)
+      for (lss = s->head; lss; lss = lss->next)
 	{
-	  know (e->loc.filenum == -1u);
-	  next = e->next;
-	  free (e);
-	}
+	  struct line_entry *e, *next;
+
+	  for (e = lss->head; e; e = next)
+	    {
+	      know (e->loc.filenum == -1u);
+	      next = e->next;
+	      free (e);
+	    }
 
-      lss->head = NULL;
-      lss->ptail = &lss->head;
-      lss->pmove_tail = &lss->head;
+	  lss->head = NULL;
+	  lss->ptail = &lss->head;
+	  lss->pmove_tail = &lss->head;
+	}
     }
 }
 
@@ -2887,15 +2891,21 @@ dwarf2_finish (void)
 			     SEC_READONLY | SEC_DEBUGGING | SEC_OCTETS);
     }
 
+  for (s = all_segs; s; s = s->next)
+    {
+      struct line_subseg *lss;
+
+      for (lss = s->head; lss; lss = lss->next)
+	if (lss->head)
+	  do_allocate_filenum (lss->head);
+    }
+
   /* For each subsection, chain the debug entries together.  */
   for (s = all_segs; s; s = s->next)
     {
       struct line_subseg *lss = s->head;
       struct line_entry **ptail = lss->ptail;
 
-      if (lss->head && SEG_NORMAL (s->seg))
-	do_allocate_filenum (lss->head);
-
       /* Reset the initial view of the first subsection of the
 	 section.  */
       if (lss->head && lss->head->loc.u.view)

-- 
Alan Modra
Australia Development Lab, IBM