Share optimized code for closures.

src/hydrogen.cc

 // Copyright 2012 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 7945 matching lines @@
   ASSERT(current_block() != NULL);
   ASSERT(current_block()->HasPredecessor());
   EqualityKind kind =
       expr->op() == Token::EQ_STRICT ? kStrictEquality : kNonStrictEquality;
   HIsNilAndBranch* instr = new(zone()) HIsNilAndBranch(value, kind, nil);
   instr->set_position(expr->position());
   return ast_context()->ReturnControl(instr, expr->id());
 }
 
 
+HInstruction* HGraphBuilder::BuildThisFunction() {
+  // If we share optimized code between different closures, the
+  // this-function is not a constant, except inside an inlined body.
+  if (function_state()->outer() != NULL) {
+      return new(zone()) HConstant(
+          function_state()->compilation_info()->closure(),
+          Representation::Tagged());
+  } else {
+      return new(zone()) HThisFunction;
+  }
+}
+
+
 void HGraphBuilder::VisitThisFunction(ThisFunction* expr) {
   ASSERT(!HasStackOverflow());
   ASSERT(current_block() != NULL);
   ASSERT(current_block()->HasPredecessor());
-  HThisFunction* self = new(zone()) HThisFunction(
-      function_state()->compilation_info()->closure());
-  return ast_context()->ReturnInstruction(self, expr->id());
+  HInstruction* instr = BuildThisFunction();
+  return ast_context()->ReturnInstruction(instr, expr->id());
 }
 
 
 void HGraphBuilder::VisitDeclarations(ZoneList<Declaration*>* declarations) {
   ASSERT(globals_.is_empty());
   AstVisitor::VisitDeclarations(declarations);
   if (!globals_.is_empty()) {
     Handle<FixedArray> array =
        isolate()->factory()->NewFixedArray(globals_.length(), TENURED);
     for (int i = 0; i < globals_.length(); ++i) array->set(i, *globals_.at(i));
@@ skipping 1194 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal