Revert of [compiler] Drop the CompareNilIC.

src/ic/ic.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/ic/ic.h"
 
 #include "src/accessors.h"
 #include "src/api.h"
 #include "src/arguments.h"
 #include "src/base/bits.h"
@@ skipping 447 matching lines @@
   if (target->is_debug_stub()) return;
 
   switch (target->kind()) {
     case Code::LOAD_IC:
     case Code::KEYED_LOAD_IC:
     case Code::STORE_IC:
     case Code::KEYED_STORE_IC:
       return;
     case Code::COMPARE_IC:
       return CompareIC::Clear(isolate, address, target, constant_pool);
+    case Code::COMPARE_NIL_IC:
+      return CompareNilIC::Clear(address, target, constant_pool);
     case Code::CALL_IC:  // CallICs are vector-based and cleared differently.
     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 2227 matching lines @@
 RUNTIME_FUNCTION(Runtime_CompareIC_Miss) {
   TimerEventScope<TimerEventIcMiss> timer(isolate);
   TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8"), "V8.IcMiss");
   HandleScope scope(isolate);
   DCHECK(args.length() == 3);
   CompareIC ic(isolate, static_cast<Token::Value>(args.smi_at(2)));
   return ic.UpdateCaches(args.at<Object>(0), args.at<Object>(1));
 }
 
 
+void CompareNilIC::Clear(Address address, Code* target, Address constant_pool) {
+  if (IsCleared(target)) return;
+  ExtraICState state = target->extra_ic_state();
+
+  CompareNilICStub stub(target->GetIsolate(), state,
+                        HydrogenCodeStub::UNINITIALIZED);
+  stub.ClearState();
+
+  Code* code = NULL;
+  CHECK(stub.FindCodeInCache(&code));
+
+  SetTargetAtAddress(address, code, constant_pool);
+}
+
+
+Handle<Object> CompareNilIC::CompareNil(Handle<Object> object) {
+  ExtraICState extra_ic_state = target()->extra_ic_state();
+
+  CompareNilICStub stub(isolate(), extra_ic_state);
+
+  // 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 = stub.IsMonomorphic();
+
+  stub.UpdateStatus(object);
+
+  // Find or create the specialized stub to support the new set of types.
+  Handle<Code> code;
+  if (stub.IsMonomorphic()) {
+    Handle<Map> monomorphic_map(already_monomorphic && FirstTargetMap() != NULL
+                                    ? FirstTargetMap()
+                                    : HeapObject::cast(*object)->map());
+    code = PropertyICCompiler::ComputeCompareNil(monomorphic_map, &stub);
+  } else {
+    code = stub.GetCode();
+  }
+  set_target(*code);
+  return isolate()->factory()->ToBoolean(object->IsUndetectableObject());
+}
+
+
+RUNTIME_FUNCTION(Runtime_CompareNilIC_Miss) {
+  TimerEventScope<TimerEventIcMiss> timer(isolate);
+  TRACE_EVENT0(TRACE_DISABLED_BY_DEFAULT("v8"), "V8.IcMiss");
+  HandleScope scope(isolate);
+  Handle<Object> object = args.at<Object>(0);
+  CompareNilIC ic(isolate);
+  return *ic.CompareNil(object);
+}
+
+
 RUNTIME_FUNCTION(Runtime_Unreachable) {
   UNREACHABLE();
   CHECK(false);
   return isolate->heap()->undefined_value();
 }
 
 
 Handle<Object> ToBooleanIC::ToBoolean(Handle<Object> object) {
   ToBooleanStub stub(isolate(), target()->extra_ic_state());
   bool to_boolean_value = stub.UpdateStatus(object);
@@ skipping 178 matching lines @@
     KeyedLoadICNexus nexus(vector, vector_slot);
     KeyedLoadIC ic(IC::EXTRA_CALL_FRAME, isolate, &nexus);
     ic.UpdateState(receiver, key);
     ASSIGN_RETURN_FAILURE_ON_EXCEPTION(isolate, result, ic.Load(receiver, key));
   }
 
   return *result;
 }
 }  // namespace internal
 }  // namespace v8