Reland "Add basic crankshaft support for slow-mode for-in to avoid disabling optimizations"

src/arm64/lithium-codegen-arm64.cc

 // Copyright 2013 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/v8.h"
 
 #include "src/arm64/lithium-codegen-arm64.h"
 #include "src/arm64/lithium-gap-resolver-arm64.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 2879 matching lines @@
 }
 
 
 void LCodeGen::DoForInPrepareMap(LForInPrepareMap* instr) {
   Register object = ToRegister(instr->object());
   Register null_value = x5;
 
   DCHECK(instr->IsMarkedAsCall());
   DCHECK(object.Is(x0));
 
-  DeoptimizeIfRoot(object, Heap::kUndefinedValueRootIndex, instr,
-                   Deoptimizer::kUndefined);
-
-  __ LoadRoot(null_value, Heap::kNullValueRootIndex);
-  __ Cmp(object, null_value);
-  DeoptimizeIf(eq, instr, Deoptimizer::kNull);
-
   DeoptimizeIfSmi(object, instr, Deoptimizer::kSmi);
 
   STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);
   __ CompareObjectType(object, x1, x1, LAST_JS_PROXY_TYPE);
   DeoptimizeIf(le, instr, Deoptimizer::kNotAJavaScriptObject);
 
   Label use_cache, call_runtime;
+  __ LoadRoot(null_value, Heap::kNullValueRootIndex);
   __ CheckEnumCache(object, null_value, x1, x2, x3, x4, &call_runtime);
 
   __ Ldr(object, FieldMemOperand(object, HeapObject::kMapOffset));
   __ B(&use_cache);
 
   // Get the set of properties to enumerate.
   __ Bind(&call_runtime);
   __ Push(object);
   CallRuntime(Runtime::kGetPropertyNamesFast, 1, instr);
 
@@ skipping 3093 matching lines @@
   Handle<ScopeInfo> scope_info = instr->scope_info();
   __ Push(scope_info);
   __ Push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 
 } }  // namespace v8::internal