1 files changed, 94 insertions, 0 deletions

diff --git a/gcc/tree.c b/gcc/tree.c
index 133feb8..b34d07c 100644
--- a/gcc/tree.c
+++ b/gcc/tree.c
@@ -131,19 +131,36 @@ static GTY (()) tree int_cst_node;
 static GTY ((if_marked ("ggc_marked_p"), param_is (union tree_node)))
      htab_t int_cst_hash_table;
 
+/* General tree->tree mapping  structure for use in hash tables.  */
+
+struct tree_map GTY(())
+{
+  hashval_t hash;
+  tree from;
+  tree to;
+};
+
+static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map))) 
+     htab_t debug_expr_for_decl;
+
 static void set_type_quals (tree, int);
 static int type_hash_eq (const void *, const void *);
 static hashval_t type_hash_hash (const void *);
+static int tree_map_eq (const void *, const void *);
+static hashval_t tree_map_hash (const void *);
 static hashval_t int_cst_hash_hash (const void *);
 static int int_cst_hash_eq (const void *, const void *);
 static void print_type_hash_statistics (void);
+static void print_debug_expr_statistics (void);
 static tree make_vector_type (tree, int, enum machine_mode);
 static int type_hash_marked_p (const void *);
+static int tree_map_marked_p (const void *);
 static unsigned int type_hash_list (tree, hashval_t);
 static unsigned int attribute_hash_list (tree, hashval_t);
 
 tree global_trees[TI_MAX];
 tree integer_types[itk_none];
+
 
 /* Init tree.c.  */
 
@@ -153,9 +170,15 @@ init_ttree (void)
   /* Initialize the hash table of types.  */
   type_hash_table = htab_create_ggc (TYPE_HASH_INITIAL_SIZE, type_hash_hash,
 				     type_hash_eq, 0);
+
+  debug_expr_for_decl = htab_create_ggc (512, tree_map_hash,
+					 tree_map_eq, 0);
+
   int_cst_hash_table = htab_create_ggc (1024, int_cst_hash_hash,
 					int_cst_hash_eq, NULL);
+  
   int_cst_node = make_node (INTEGER_CST);
+
 }
 
 
@@ -3430,6 +3453,76 @@ build_variant_type_copy (tree type)
   return t;
 }
 
+/* Return true if the from tree in both tree maps are equal.  */
+
+static int
+tree_map_eq (const void *va, const void *vb)
+{
+  const struct tree_map  *a = va, *b = vb;
+  return (a->from == b->from);
+}
+
+/* Hash a from tree in a tree_map.  */
+
+static hashval_t
+tree_map_hash (const void *item)
+{
+  return (((const struct tree_map *) item)->hash);
+}
+
+/* Return true if this tree map structure is marked for garbage collection
+   purposes.  We simply return true if the from tree is marked, so that this
+   structure goes away when the from tree goes away.  */
+
+static int
+tree_map_marked_p (const void *p)
+{
+  tree from = ((struct tree_map *) p)->from;
+
+  return ggc_marked_p (from);
+}
+
+/* Print out the statistics for the DECL_DEBUG_EXPR hash table.  */
+
+static void
+print_debug_expr_statistics (void)
+{
+  fprintf (stderr, "DECL_DEBUG_EXPR  hash: size %ld, %ld elements, %f collisions\n",
+	   (long) htab_size (debug_expr_for_decl),
+	   (long) htab_elements (debug_expr_for_decl),
+	   htab_collisions (debug_expr_for_decl));
+}
+
+/* Lookup a debug expression for FROM, and return it if we find one.  */
+
+tree 
+decl_debug_expr_lookup (tree from)
+{
+  struct tree_map *h, in;
+  in.from = from;
+
+  h = htab_find_with_hash (debug_expr_for_decl, &in, htab_hash_pointer (from));
+  if (h)
+    return h->to;
+  return NULL_TREE;
+}
+
+/* Insert a mapping FROM->TO in the debug expression hashtable.  */
+
+void
+decl_debug_expr_insert (tree from, tree to)
+{
+  struct tree_map *h;
+  void **loc;
+
+  h = ggc_alloc (sizeof (struct tree_map));
+  h->hash = htab_hash_pointer (from);
+  h->from = from;
+  h->to = to;
+  loc = htab_find_slot_with_hash (debug_expr_for_decl, h, h->hash, INSERT);
+  *(struct tree_map **) loc = h;
+}  
+  
 /* Hashing of types so that we don't make duplicates.
    The entry point is `type_hash_canon'.  */
 
@@ -5261,6 +5354,7 @@ dump_tree_statistics (void)
   fprintf (stderr, "(No per-node statistics)\n");
 #endif
   print_type_hash_statistics ();
+  print_debug_expr_statistics ();
   lang_hooks.print_statistics ();
 }