Maintain the invariant that all HGraphBuilder::VisitFoo methods return void.

Additionally, this enables the use of a CHECK_ALIVE macro instead of
copy-n-paste code at one place.

This CL is part of a series of several yak-shaving CLs to prepare the inlining
of JavaScript accessors.

Review URL: https://chromiumcodereview.appspot.com/10783017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12093 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/hydrogen.cc

@@ -2992,12 +2992,9 @@ void HGraphBuilder::VisitForControl(Expression* expr,
 }
 
 
-HValue* HGraphBuilder::VisitArgument(Expression* expr) {
-  VisitForValue(expr);
-  if (HasStackOverflow() || current_block() == NULL) return NULL;
-  HValue* value = Pop();
-  Push(AddInstruction(new(zone()) HPushArgument(value)));
-  return value;
+void HGraphBuilder::VisitArgument(Expression* expr) {
+  CHECK_ALIVE(VisitForValue(expr));
+  Push(AddInstruction(new(zone()) HPushArgument(Pop())));
 }
 
 
@@ -7450,8 +7447,8 @@ void HGraphBuilder::VisitCallNew(CallNew* expr) {
   } else {
     // The constructor function is both an operand to the instruction and an
     // argument to the construct call.
-    HValue* constructor = NULL;
-    CHECK_ALIVE(constructor = VisitArgument(expr->expression()));
+    CHECK_ALIVE(VisitArgument(expr->expression()));
+    HValue* constructor = HPushArgument::cast(Top())->argument();
     CHECK_ALIVE(VisitArgumentList(expr->arguments()));
     HInstruction* call =
         new(zone()) HCallNew(context, constructor, argument_count);

src/hydrogen.h

@@ -976,9 +976,8 @@ class HGraphBuilder: public AstVisitor {
                        HBasicBlock* true_block,
                        HBasicBlock* false_block);
 
-  // Visit an argument subexpression and emit a push to the outgoing
-  // arguments.  Returns the hydrogen value that was pushed.
-  HValue* VisitArgument(Expression* expr);
+  // Visit an argument subexpression and emit a push to the outgoing arguments.
+  void VisitArgument(Expression* expr);
 
   void VisitArgumentList(ZoneList<Expression*>* arguments);