Replace ICStub for array.length with hydrogen stub

src/code-stubs-hydrogen.cc

Index: src/code-stubs-hydrogen.cc
diff --git a/src/code-stubs-hydrogen.cc b/src/code-stubs-hydrogen.cc
index ab2fb08a44c12e85491f7b67fd527b802fc2a0f7..64e6e0a912a4cc2e95416266230cb2acfd356e4e 100644
--- a/src/code-stubs-hydrogen.cc
+++ b/src/code-stubs-hydrogen.cc
@@ -30,6 +30,7 @@
 #include "code-stubs.h"
 #include "hydrogen.h"
 #include "lithium.h"
+#include "stub-cache.h"
 
 namespace v8 {
 namespace internal {
@@ -237,6 +238,33 @@ Handle<Code> KeyedLoadFastElementStub::GenerateCode() {
 
 
 template <>
+HValue* CodeStubGraphBuilder<FastArrayLengthStub>::BuildCodeStub() {
+  HInstruction* load = BuildFastArrayLengthLoad(GetParameter(0));
+  AddInstruction(load);
+  return load;
+}
+
+
+Handle<Code> FastArrayLengthStub::GenerateCode() {
+  CodeStubGraphBuilder<FastArrayLengthStub> builder(this);
+  LChunk* chunk = OptimizeGraph(builder.CreateGraph());
+  return chunk->Codegen(Code::COMPILED_STUB);
+}
+
+void FastArrayLengthStub::InitializeInterfaceDescriptor(
+    Isolate* isolate,
+    CodeStubInterfaceDescriptor* descriptor) {
+  descriptor->register_param_count_ = 2;

[danno, 2013/03/12 11:16:16]

Descriptors are persistent, but the lifetime of registers_ is not. 

+  // See LoadStubCompiler::registers().
+  registers_[0] = receiver_;
+  registers_[1] = LoadStubCompiler::name();
+  descriptor->register_params_ = registers_;
+  descriptor->deoptimization_handler_ =
+      Runtime::FunctionForId(Runtime::kUnexpectedDeopt)->entry;
+}
+
+
+template <>
 HValue* CodeStubGraphBuilder<TransitionElementsKindStub>::BuildCodeStub() {
   Zone* zone = this->zone();