[llvm-commits] llvm-gcc patch: Map Stomp

[Bill Wendling]

Hi all,

I committed this patch. It's one that was committed Apple's GCC. It  
solves a problem where an address gotten from a map could be stomped  
on by a subsequent call-back function.

-bw

In the libcpp directory:

2007-01-06  Bill Wendling  <wendling at apple.com>

         Radar 4897123
         * directives.c (_cpp_do_file_change): Array of maps could  
change after
         the "file_change" callback. We should relookup the map  
afterwards.

Index: directives.c
===================================================================
--- directives.c        (revision 240)
+++ directives.c        (working copy)
@@ -943,8 +943,24 @@
    if (map != NULL)
      linemap_line_start (pfile->line_table, map->to_line, 127);
+  /* APPLE LOCAL begin 4897123 */
    if (pfile->cb.file_change)
-    pfile->cb.file_change (pfile, map);
+    {
+      struct line_map *old_maps = pfile->line_table->maps;
+      source_location old_loc = 0;
+
+      if (map)
+        old_loc = map->start_location;
+
+      pfile->cb.file_change (pfile, map);
+
+      /* The file_change callback could reallocate the line_table  
maps causing
+         "map" we got to be invalid */
+      if (map && old_maps != pfile->line_table->maps)
+        map = linemap_lookup (pfile->line_table, old_loc);
+    }
+  /* APPLE LOCAL end 4897123 */
+
    /* APPLE LOCAL begin 4137741 */
    /* If file change debug hook callbacks are being deferred, we will