HydrogenCodeStubs consume stack arguments via descriptor.

src/ia32/interface-descriptors-ia32.cc

Index: src/ia32/interface-descriptors-ia32.cc
diff --git a/src/ia32/interface-descriptors-ia32.cc b/src/ia32/interface-descriptors-ia32.cc
index e1138b959de063cbaef3cb4334d114b10a5be974..17b053c5719c3a498542c590ab17a54fb5f29779 100644
--- a/src/ia32/interface-descriptors-ia32.cc
+++ b/src/ia32/interface-descriptors-ia32.cc
@@ -32,7 +32,9 @@ const Register VectorStoreICTrampolineDescriptor::SlotRegister() { return edi; }
 const Register VectorStoreICDescriptor::VectorRegister() { return ebx; }
 
 
-const Register StoreTransitionDescriptor::MapRegister() { return ebx; }
+const Register StoreTransitionDescriptor::MapRegister() {
+  return FLAG_vector_stores ? no_reg : ebx;
+}
 
 
 const Register LoadGlobalViaContextDescriptor::DepthRegister() { return edx; }
@@ -69,6 +71,20 @@ const Register GrowArrayElementsDescriptor::ObjectRegister() { return eax; }
 const Register GrowArrayElementsDescriptor::KeyRegister() { return ebx; }
 
 
+void StoreTransitionDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  Register registers[] = {ReceiverRegister(), NameRegister(), ValueRegister(),
+                          MapRegister()};
+
+  // When FLAG_vector_stores is true, we want to pass the map register on the
+  // stack instead of in a register.
+  DCHECK(FLAG_vector_stores || !MapRegister().is(no_reg));
+
+  int register_count = FLAG_vector_stores ? 3 : 4;
+  data->InitializePlatformSpecific(register_count, registers);
+}
+
+
 void FastNewClosureDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {ebx};