[LTO] PATCH: Fix for ICE vector VEC(cgraph_node_ptr,base) index domain error

[Simon Baldwin]

Callgraph nodes are not necessarily written out in such an order that an
inlined function can always locate the function that inlines it.  Sometimes,
the function that inlines it has not yet been read.

This patch addresses that by deferring node lookup by reference until all of
the callgraph nodes have been read, and fixes the following:

  extern inline void __attribute__((__always_inline__)) func(void) { }
  void f(void) { func(); }

  $ gcc -c -fwhopr -o f.o f.c
  $ gcc -shared -fwhopr -o f.so f.o
  lto1: internal compiler error: vector VEC(cgraph_node_ptr,base) index
  domain error, in input_node at lto/lto-lang.c:1216


gcc/lto/ChangeLog
2008-10-22  Simon Baldwin  <simonb@google.com>

	* lto-lang.c: (input_node): Save the node reference, rather than the
	node pointer, in node->inlined_to.
	(fixup_cgraph_nodes): New function, convert node references into
	node pointers.
	(input_cgraph_1): Call fixup_cgraph_nodes.


Index: gcc/lto/lto-lang.c
===================================================================
--- gcc/lto/lto-lang.c	(revision 141263)
+++ gcc/lto/lto-lang.c	(working copy)
@@ -1212,10 +1212,10 @@ input_node (struct lto_file_decl_data* f
 	  node->global.estimated_stack_size = estimated_stack_size;
 	  node->global.stack_frame_offset = stack_frame_offset;
 	  node->global.insns = insns;
-	  if (ref != LCC_NOT_FOUND)
-	    node->global.inlined_to = VEC_index (cgraph_node_ptr, nodes, ref);
-	  else
-	    node->global.inlined_to = NULL;
+
+          /* Store a reference for now, and fix up later to be a pointer.  */
+          node->global.inlined_to = (graph_node_ptr) ref;
+
 	  node->global.estimated_growth = estimated_growth;
 	  node->global.inlined = inlined;
 	}
@@ -1270,6 +1270,26 @@ input_edge (struct lto_input_block *ib, 
   edge->indirect_call = lto_get_flag (&flags);
 }
 
+/* Callgraph node inlined_to fields are currently references; here is where
+   we convert them into node pointers.  */
+
+static void
+fixup_cgraph_nodes (VEC(cgraph_node_ptr, heap) *nodes)
+{
+  int i;
+
+  for (i = 0; VEC_iterate (cgraph_node_ptr, nodes, i, node); i++)
+    {
+      const int ref = (int) node->global.inlined_to;
+
+      if (ref != LCC_NOT_FOUND)
+        node->global.inlined_to = VEC_index (cgraph_node_ptr, nodes, ref);
+      else
+        node->global.inlined_to = NULL;
+    }
+
+}
+
 /* Input a cgraph from IB using the info in FILE_DATA.  */
 
 static void
@@ -1286,7 +1306,7 @@ input_cgraph_1 (struct lto_file_decl_dat
       LTO_DEBUG_INDENT (tag);
 
       if (tag == LTO_cgraph_edge)
-	  input_edge (ib, nodes);
+        input_edge (ib, nodes);
       else 
 	{
 	  node = input_node (file_data, ib, tag, nodes);
@@ -1297,6 +1317,7 @@ input_cgraph_1 (struct lto_file_decl_dat
       tag = lto_input_uleb128 (ib);
     }
 
+  fixup_cgraph_nodes (nodes);
   VEC_free (cgraph_node_ptr, heap, nodes);
 }