Add an IC for CompareNil operations

src/ic.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 329 matching lines @@
   if (target->is_debug_break()) return;
 
   switch (target->kind()) {
     case Code::LOAD_IC: return LoadIC::Clear(address, target);
     case Code::KEYED_LOAD_IC: return KeyedLoadIC::Clear(address, target);
     case Code::STORE_IC: return StoreIC::Clear(address, target);
     case Code::KEYED_STORE_IC: return KeyedStoreIC::Clear(address, target);
     case Code::CALL_IC: return CallIC::Clear(address, target);
     case Code::KEYED_CALL_IC:  return KeyedCallIC::Clear(address, target);
     case Code::COMPARE_IC: return CompareIC::Clear(address, target);
+    case Code::COMPARE_NIL_IC: return CompareNilIC::Clear(address, target);
     case Code::UNARY_OP_IC:
     case Code::BINARY_OP_IC:
     case Code::TO_BOOLEAN_IC:
       // Clearing these is tricky and does not
       // make any performance difference.
       return;
     default: UNREACHABLE();
   }
 }
 
@@ skipping 2399 matching lines @@
 // Used from ICCompareStub::GenerateMiss in code-stubs-<arch>.cc.
 RUNTIME_FUNCTION(Code*, CompareIC_Miss) {
   NoHandleAllocation na(isolate);
   ASSERT(args.length() == 3);
   CompareIC ic(isolate, static_cast<Token::Value>(args.smi_at(2)));
   ic.UpdateCaches(args.at<Object>(0), args.at<Object>(1));
   return ic.target();
 }
 
 
+Handle<Code> CompareNilIC::GetUninitialized() {
+  CompareNilICStub stub;
+  return stub.GetCode(Isolate::Current());
+}
+
+
+Code* CompareNilIC::GetRawUninitialized() {
+  CompareNilICStub stub;
+  Code* code = NULL;
+  CHECK(stub.FindCodeInCache(&code, Isolate::Current()));
+  return code;
+}
+
+
+void CompareNilIC::Clear(Address address, Code* target) {
+  if (target->ic_state() == UNINITIALIZED) return;
+  SetTargetAtAddress(address, GetRawUninitialized());
+}
+
+
+MaybeObject* CompareNilIC::DoCompareNilSlow(EqualityKind kind,
+                                            NilValue nil,
+                                            Handle<Object> object) {
+  if (kind == kStrictEquality) {
+    if (nil == kNullValue) {
+      return Smi::FromInt(object->IsNull());
+    } else {
+      return Smi::FromInt(object->IsUndefined());
+    }
+  }
+  if (Smi::FromInt(object->IsNull() || object->IsUndefined())) {
+    return Smi::FromInt(true);
+  }
+  return Smi::FromInt(object->IsUndetectableObject());
+}
+
+
+MaybeObject* CompareNilIC::CompareNil(EqualityKind kind,
+                                      NilValue nil,
+                                      Handle<Object> object) {
+  // Extract the current supported types from the patched IC and calculate what
+  // types must be supported as a result of the miss.
+  bool already_monomorphic;
+  CompareNilICStub::Types types =
+      CompareNilICStub::GetPatchedICFlags(target(), kind, nil,
+                                          object, &already_monomorphic);
+
+  // Find or create the specialized stub to support the new set of types.
+  CompareNilICStub stub(kind, types);
+  Handle<Code> code;
+  if ((types & CompareNilICStub::kCompareAgainstMonomorphicMap) != 0) {
+    Handle<Map> monomorphic_map(already_monomorphic
+                                ? target()->FindFirstMap()
+                                : HeapObject::cast(*object)->map());
+    code = isolate()->stub_cache()->ComputeCompareNil(monomorphic_map,
+                                                      stub.GetTypes());
+  } else {
+    code = stub.GetCode(isolate());
+  }
+
+  patch(*code);
+
+  return DoCompareNilSlow(kind, nil, object);
+}
+
+
+void CompareNilIC::patch(Code* code) {
+  set_target(code);
+}
+
+
+RUNTIME_FUNCTION(MaybeObject*, CompareNilIC_Miss) {
+  HandleScope scope(isolate);
+  EqualityKind kind = static_cast<EqualityKind>(args.smi_at(0));
+  NilValue nil = static_cast<NilValue>(args.smi_at(1));
+  Handle<Object> object = args.at<Object>(2);
+  CompareNilIC ic(isolate);
+  return ic.CompareNil(kind, nil, object);
+}
+
+
 RUNTIME_FUNCTION(MaybeObject*, Unreachable) {
   UNREACHABLE();
   CHECK(false);
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(MaybeObject*, ToBoolean_Patch) {
   ASSERT(args.length() == 3);
 
@@ skipping 26 matching lines @@
 #undef ADDR
 };
 
 
 Address IC::AddressFromUtilityId(IC::UtilityId id) {
   return IC_utilities[id];
 }
 
 
 } }  // namespace v8::internal