Restart AST node numbering when we enter a function.

src/hydrogen.cc

Index: src/hydrogen.cc
diff --git a/src/hydrogen.cc b/src/hydrogen.cc
index 056cf6a19bc7f301478a049b09576ed3ad5853d5..151c29669472ff8bc9df32433cc1a6cc1d943f92 100644
--- a/src/hydrogen.cc
+++ b/src/hydrogen.cc
@@ -582,7 +582,7 @@ HGraph::HGraph(CompilationInfo* info)
       phi_list_(NULL) {
   start_environment_ =
       new(zone()) HEnvironment(NULL, info->scope(), info->closure());
-  start_environment_->set_ast_id(info->function()->id());
+  start_environment_->set_ast_id(AstNode::kRootAstId);
   entry_block_ = CreateBasicBlock();
   entry_block_->SetInitialEnvironment(start_environment_);
 }
@@ -2203,7 +2203,7 @@ HGraph* HGraphBuilder::CreateGraph() {
     HEnvironment* initial_env = environment()->CopyWithoutHistory();
     HBasicBlock* body_entry = CreateBasicBlock(initial_env);
     current_block()->Goto(body_entry);
-    body_entry->SetJoinId(info()->function()->id());
+    body_entry->SetJoinId(AstNode::kRootAstId);
     set_current_block(body_entry);
     VisitStatements(info()->function()->body());
     if (HasStackOverflow()) return NULL;
@@ -5674,7 +5674,7 @@ HEnvironment* HEnvironment::CopyForInlining(Handle<JSFunction> target,
     inner->SetValueAt(local_base + i, undefined);
   }
 
-  inner->set_ast_id(function->id());
+  inner->set_ast_id(AstNode::kRootAstId);
   return inner;
 }