X87: VectorICs: New interface descriptor for vector transitioning stores.

port cd351559 (r30284).

original commit message:

BUG=

Review URL: https://codereview.chromium.org/1303223002

Cr-Commit-Position: refs/heads/master@{#30297}

src/x87/interface-descriptors-x87.cc

@@ -30,11 +30,22 @@ const Register VectorStoreICTrampolineDescriptor::SlotRegister() { return edi; }
 const Register VectorStoreICDescriptor::VectorRegister() { return ebx; }
 
 
-const Register StoreTransitionDescriptor::MapRegister() {
-  return FLAG_vector_stores ? no_reg : ebx;
+const Register VectorStoreTransitionDescriptor::SlotRegister() {
+  return no_reg;
 }
 
 
+const Register VectorStoreTransitionDescriptor::VectorRegister() {
+  return no_reg;
+}
+
+
+const Register VectorStoreTransitionDescriptor::MapRegister() { return no_reg; }
+
+
+const Register StoreTransitionDescriptor::MapRegister() { return ebx; }
+
+
 const Register LoadGlobalViaContextDescriptor::SlotRegister() { return ebx; }
 
 
@@ -65,17 +76,11 @@ const Register GrowArrayElementsDescriptor::ObjectRegister() { return eax; }
 const Register GrowArrayElementsDescriptor::KeyRegister() { return ebx; }
 
 
-void StoreTransitionDescriptor::InitializePlatformSpecific(
+void VectorStoreTransitionDescriptor::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);
+  Register registers[] = {ReceiverRegister(), NameRegister(), ValueRegister()};
+  // The other three parameters are on the stack in ia32.
+  data->InitializePlatformSpecific(arraysize(registers), registers);
 }