Revert relanded strong property access CL

src/ic/x64/ic-x64.cc

Index: src/ic/x64/ic-x64.cc
diff --git a/src/ic/x64/ic-x64.cc b/src/ic/x64/ic-x64.cc
index 6d40a50fbbdb3dd824b4373688bf7597a39f6e7e..40aa231fd34db3989b64cfb9c010b8a1ba8b14d5 100644
--- a/src/ic/x64/ic-x64.cc
+++ b/src/ic/x64/ic-x64.cc
@@ -171,7 +171,7 @@ static void GenerateKeyedLoadReceiverCheck(MacroAssembler* masm,
 static void GenerateFastArrayLoad(MacroAssembler* masm, Register receiver,
                                   Register key, Register elements,
                                   Register scratch, Register result,
-                                  Label* slow, LanguageMode language_mode) {
+                                  Label* slow) {
   // Register use:
   //
   // receiver - holds the receiver on entry.
@@ -191,7 +191,7 @@ static void GenerateFastArrayLoad(MacroAssembler* masm, Register receiver,
   //
   // scratch  - used to hold maps, prototypes, and the loaded value.
   Label check_prototypes, check_next_prototype;
-  Label done, in_bounds, absent;
+  Label done, in_bounds, return_undefined;
 
   __ movp(elements, FieldOperand(receiver, JSObject::kElementsOffset));
   __ AssertFastElements(elements);
@@ -210,7 +210,7 @@ static void GenerateFastArrayLoad(MacroAssembler* masm, Register receiver,
   __ movp(scratch, FieldOperand(scratch, Map::kPrototypeOffset));
   // scratch: current prototype
   __ CompareRoot(scratch, Heap::kNullValueRootIndex);
-  __ j(equal, &absent);
+  __ j(equal, &return_undefined);
   __ movp(elements, FieldOperand(scratch, JSObject::kElementsOffset));
   __ movp(scratch, FieldOperand(scratch, HeapObject::kMapOffset));
   // elements: elements of current prototype
@@ -225,14 +225,9 @@ static void GenerateFastArrayLoad(MacroAssembler* masm, Register receiver,
   __ j(not_equal, slow);
   __ jmp(&check_next_prototype);
 
-  __ bind(&absent);
-  if (is_strong(language_mode)) {
-    // Strong mode accesses must throw in this case, so call the runtime.
-    __ jmp(slow);
-  } else {
-    __ LoadRoot(result, Heap::kUndefinedValueRootIndex);
-    __ jmp(&done);
-  }
+  __ bind(&return_undefined);
+  __ LoadRoot(result, Heap::kUndefinedValueRootIndex);
+  __ jmp(&done);
 
   __ bind(&in_bounds);
   // Fast case: Do the load.
@@ -279,8 +274,7 @@ static void GenerateKeyNameCheck(MacroAssembler* masm, Register key,
 }
 
 
-void KeyedLoadIC::GenerateMegamorphic(MacroAssembler* masm,
-                                      LanguageMode language_mode) {
+void KeyedLoadIC::GenerateMegamorphic(MacroAssembler* masm) {
   // The return address is on the stack.
   Label slow, check_name, index_smi, index_name, property_array_property;
   Label probe_dictionary, check_number_dictionary;
@@ -302,8 +296,7 @@ void KeyedLoadIC::GenerateMegamorphic(MacroAssembler* masm,
   // Check the receiver's map to see if it has fast elements.
   __ CheckFastElements(rax, &check_number_dictionary);
 
-  GenerateFastArrayLoad(masm, receiver, key, rax, rbx, rax, &slow,
-                        language_mode);
+  GenerateFastArrayLoad(masm, receiver, key, rax, rbx, rax, &slow);
   Counters* counters = masm->isolate()->counters();
   __ IncrementCounter(counters->keyed_load_generic_smi(), 1);
   __ ret(0);
@@ -324,7 +317,7 @@ void KeyedLoadIC::GenerateMegamorphic(MacroAssembler* masm,
   __ bind(&slow);
   // Slow case: Jump to runtime.
   __ IncrementCounter(counters->keyed_load_generic_slow(), 1);
-  GenerateSlow(masm);
+  GenerateRuntimeGetProperty(masm);
 
   __ bind(&check_name);
   GenerateKeyNameCheck(masm, key, rax, rbx, &index_name, &slow);
@@ -630,7 +623,7 @@ void LoadIC::GenerateNormal(MacroAssembler* masm) {
 
   // Dictionary load failed, go slow (but don't miss).
   __ bind(&slow);
-  GenerateSlow(masm);
+  GenerateRuntimeGetProperty(masm);
 }
 
 
@@ -667,7 +660,7 @@ void LoadIC::GenerateMiss(MacroAssembler* masm) {
 }
 
 
-void LoadIC::GenerateSlow(MacroAssembler* masm) {
+void LoadIC::GenerateRuntimeGetProperty(MacroAssembler* masm) {
   // The return address is on the stack.
   Register receiver = LoadDescriptor::ReceiverRegister();
   Register name = LoadDescriptor::NameRegister();
@@ -679,10 +672,7 @@ void LoadIC::GenerateSlow(MacroAssembler* masm) {
   __ PushReturnAddressFrom(rbx);
 
   // Perform tail call to the entry.
-  ExternalReference ref =
-      ExternalReference(IC_Utility(kLoadIC_Slow), masm->isolate());
-  int arg_count = 2;
-  __ TailCallExternalReference(ref, arg_count, 1);
+  __ TailCallRuntime(Runtime::kGetProperty, 2, 1);
 }
 
 
@@ -701,7 +691,7 @@ void KeyedLoadIC::GenerateMiss(MacroAssembler* masm) {
 }
 
 
-void KeyedLoadIC::GenerateSlow(MacroAssembler* masm) {
+void KeyedLoadIC::GenerateRuntimeGetProperty(MacroAssembler* masm) {
   // The return address is on the stack.
   Register receiver = LoadDescriptor::ReceiverRegister();
   Register name = LoadDescriptor::NameRegister();
@@ -713,10 +703,7 @@ void KeyedLoadIC::GenerateSlow(MacroAssembler* masm) {
   __ PushReturnAddressFrom(rbx);
 
   // Perform tail call to the entry.
-  ExternalReference ref =
-      ExternalReference(IC_Utility(kKeyedLoadIC_Slow), masm->isolate());
-  int arg_count = 2;
-  __ TailCallExternalReference(ref, arg_count, 1);
+  __ TailCallRuntime(Runtime::kKeyedGetProperty, 2, 1);
 }