Fix a bug with uninitialized const variables in the optimizing compiler.

src/hydrogen.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 834 matching lines @@
     HPhi* phi = phi_list[i];
     if (!phi->is_live()) {
       HBasicBlock* block = phi->block();
       block->RemovePhi(phi);
       block->RecordDeletedPhi(phi->merged_index());
     }
   }
 }
 
 
-bool HGraph::CheckPhis() {
+bool HGraph::CheckArgumentsPhiUses() {
   int block_count = blocks_.length();
   for (int i = 0; i < block_count; ++i) {
     for (int j = 0; j < blocks_[i]->phis()->length(); ++j) {
       HPhi* phi = blocks_[i]->phis()->at(j);
       // We don't support phi uses of arguments for now.
       if (phi->CheckFlag(HValue::kIsArguments)) return false;
     }
   }
   return true;
 }
 
 
-bool HGraph::CollectPhis() {
+bool HGraph::CheckConstPhiUses() {
   int block_count = blocks_.length();
-  phi_list_ = new ZoneList<HPhi*>(block_count);
   for (int i = 0; i < block_count; ++i) {
     for (int j = 0; j < blocks_[i]->phis()->length(); ++j) {
       HPhi* phi = blocks_[i]->phis()->at(j);
-      phi_list_->Add(phi);
       // Check for the hole value (from an uninitialized const).
       for (int k = 0; k < phi->OperandCount(); k++) {
         if (phi->OperandAt(k) == GetConstantHole()) return false;
       }
     }
   }
   return true;
 }
 
 
+void HGraph::CollectPhis() {
+  int block_count = blocks_.length();
+  phi_list_ = new ZoneList<HPhi*>(block_count);
+  for (int i = 0; i < block_count; ++i) {
+    for (int j = 0; j < blocks_[i]->phis()->length(); ++j) {
+      HPhi* phi = blocks_[i]->phis()->at(j);
+      phi_list_->Add(phi);
+    }
+  }
+}
+
+
 void HGraph::InferTypes(ZoneList<HValue*>* worklist) {
   BitVector in_worklist(GetMaximumValueID());
   for (int i = 0; i < worklist->length(); ++i) {
     ASSERT(!in_worklist.Contains(worklist->at(i)->id()));
     in_worklist.Add(worklist->at(i)->id());
   }
 
   while (!worklist->is_empty()) {
     HValue* current = worklist->RemoveLast();
     in_worklist.Remove(current->id());
@@ skipping 1427 matching lines @@
 
   graph()->OrderBlocks();
   graph()->AssignDominators();
 
 #ifdef DEBUG
   // Do a full verify after building the graph and computing dominators.
   graph()->Verify(true);
 #endif
 
   graph()->PropagateDeoptimizingMark();
+  if (!graph()->CheckConstPhiUses()) {
+    Bailout("Unsupported phi use of const variable");
+    return NULL;
+  }
   graph()->EliminateRedundantPhis();
-  if (!graph()->CheckPhis()) {
-    Bailout("Unsupported phi use of arguments object");
+  if (!graph()->CheckArgumentsPhiUses()) {
+    Bailout("Unsupported phi use of arguments");
     return NULL;
   }
   if (FLAG_eliminate_dead_phis) graph()->EliminateUnreachablePhis();
-  if (!graph()->CollectPhis()) {
-    Bailout("Unsupported phi use of uninitialized constant");
-    return NULL;
-  }
+  graph()->CollectPhis();
 
   HInferRepresentation rep(graph());
   rep.Analyze();
 
   graph()->MarkDeoptimizeOnUndefined();
   graph()->InsertRepresentationChanges();
 
   graph()->InitializeInferredTypes();
   graph()->Canonicalize();
 
@@ skipping 4475 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal