Make Failure inherit from MaybeObject instead of Object.

src/x64/stub-cache-x64.cc

 // Copyright 2010 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 778 matching lines @@
 
   StubCompiler* stub_compiler_;
   const ParameterCount& arguments_;
   Register name_;
 };
 
 
 // Generate code to check that a global property cell is empty. Create
 // the property cell at compilation time if no cell exists for the
 // property.
-static Object* GenerateCheckPropertyCell(MacroAssembler* masm,
-                                         GlobalObject* global,
-                                         String* name,
-                                         Register scratch,
-                                         Label* miss) {
-  Object* probe = global->EnsurePropertyCell(name);
-  if (probe->IsFailure()) return probe;
+MUST_USE_RESULT static MaybeObject* GenerateCheckPropertyCell(
+    MacroAssembler* masm,
+    GlobalObject* global,
+    String* name,
+    Register scratch,
+    Label* miss) {
+  Object* probe;
+  { MaybeObject* maybe_probe = global->EnsurePropertyCell(name);
+    if (!maybe_probe->ToObject(&probe)) return maybe_probe;
+  }
   JSGlobalPropertyCell* cell = JSGlobalPropertyCell::cast(probe);
   ASSERT(cell->value()->IsTheHole());
   __ Move(scratch, Handle<Object>(cell));
   __ Cmp(FieldOperand(scratch, JSGlobalPropertyCell::kValueOffset),
          Factory::the_hole_value());
   __ j(not_equal, miss);
   return cell;
 }
 
 
@@ skipping 56 matching lines @@
     __ Move(rax, Handle<SharedFunctionInfo>(function->shared()));
     __ cmpq(FieldOperand(rdi, JSFunction::kSharedFunctionInfoOffset), rax);
     __ j(not_equal, miss);
   } else {
     __ Cmp(rdi, Handle<JSFunction>(function));
     __ j(not_equal, miss);
   }
 }
 
 
-Object* CallStubCompiler::GenerateMissBranch() {
-  Object* obj = StubCache::ComputeCallMiss(arguments().immediate(), kind_);
-  if (obj->IsFailure()) return obj;
+MaybeObject* CallStubCompiler::GenerateMissBranch() {
+  Object* obj;
+  { MaybeObject* maybe_obj =
+        StubCache::ComputeCallMiss(arguments().immediate(), kind_);
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
   __ Jump(Handle<Code>(Code::cast(obj)), RelocInfo::CODE_TARGET);
   return obj;
 }
 
 
-Object* CallStubCompiler::CompileCallConstant(Object* object,
-                                              JSObject* holder,
-                                              JSFunction* function,
-                                              String* name,
-                                              StubCompiler::CheckType check) {
+MaybeObject* CallStubCompiler::CompileCallConstant(
+    Object* object,
+    JSObject* holder,
+    JSFunction* function,
+    String* name,
+    StubCompiler::CheckType check) {
   // ----------- S t a t e -------------
   // rcx                 : function name
   // rsp[0]              : return address
   // rsp[8]              : argument argc
   // rsp[16]             : argument argc - 1
   // ...
   // rsp[argc * 8]       : argument 1
   // rsp[(argc + 1) * 8] : argument 0 = receiver
   // -----------------------------------
 
   SharedFunctionInfo* function_info = function->shared();
   if (function_info->HasCustomCallGenerator()) {
     const int id = function_info->custom_call_generator_id();
-    Object* result = CompileCustomCall(
+    MaybeObject* maybe_result = CompileCustomCall(
         id, object, holder,  NULL, function, name);
+    Object* result;
+    if (!maybe_result->ToObject(&result)) return maybe_result;
     // undefined means bail out to regular compiler.
     if (!result->IsUndefined()) return result;
   }
 
   Label miss_in_smi_check;
 
   GenerateNameCheck(name, &miss_in_smi_check);
 
   // Get the receiver from the stack.
   const int argc = arguments().immediate();
@@ skipping 107 matching lines @@
   }
 
   // Handle call cache miss.
   __ bind(&miss);
   if (depth != kInvalidProtoDepth) {
     FreeSpaceForFastApiCall(masm(), rax);
   }
 
   // Handle call cache miss.
   __ bind(&miss_in_smi_check);
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return GetCode(function);
 }
 
 
-Object* CallStubCompiler::CompileCallField(JSObject* object,
-                                           JSObject* holder,
-                                           int index,
-                                           String* name) {
+MaybeObject* CallStubCompiler::CompileCallField(JSObject* object,
+                                                JSObject* holder,
+                                                int index,
+                                                String* name) {
   // ----------- S t a t e -------------
   // rcx                 : function name
   // rsp[0]              : return address
   // rsp[8]              : argument argc
   // rsp[16]             : argument argc - 1
   // ...
   // rsp[argc * 8]       : argument 1
   // rsp[(argc + 1) * 8] : argument 0 = receiver
   // -----------------------------------
   Label miss;
@@ skipping 23 matching lines @@
   if (object->IsGlobalObject()) {
     __ movq(rdx, FieldOperand(rdx, GlobalObject::kGlobalReceiverOffset));
     __ movq(Operand(rsp, (argc + 1) * kPointerSize), rdx);
   }
 
   // Invoke the function.
   __ InvokeFunction(rdi, arguments(), JUMP_FUNCTION);
 
   // Handle call cache miss.
   __ bind(&miss);
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return GetCode(FIELD, name);
 }
 
 
-Object* CallStubCompiler::CompileArrayPushCall(Object* object,
-                                               JSObject* holder,
-                                               JSGlobalPropertyCell* cell,
-                                               JSFunction* function,
-                                               String* name) {
+MaybeObject* CallStubCompiler::CompileArrayPushCall(Object* object,
+                                                    JSObject* holder,
+                                                    JSGlobalPropertyCell* cell,
+                                                    JSFunction* function,
+                                                    String* name) {
   // ----------- S t a t e -------------
   //  -- rcx                 : name
   //  -- rsp[0]              : return address
   //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
   //  -- ...
   //  -- rsp[(argc + 1) * 8] : receiver
   // -----------------------------------
 
   // If object is not an array, bail out to regular call.
   if (!object->IsJSArray() || cell != NULL) return Heap::undefined_value();
@@ skipping 129 matching lines @@
       __ ret((argc + 1) * kPointerSize);
     }
 
     __ bind(&call_builtin);
     __ TailCallExternalReference(ExternalReference(Builtins::c_ArrayPush),
                                  argc + 1,
                                  1);
   }
 
   __ bind(&miss);
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return GetCode(function);
 }
 
 
-Object* CallStubCompiler::CompileArrayPopCall(Object* object,
-                                              JSObject* holder,
-                                              JSGlobalPropertyCell* cell,
-                                              JSFunction* function,
-                                              String* name) {
+MaybeObject* CallStubCompiler::CompileArrayPopCall(Object* object,
+                                                   JSObject* holder,
+                                                   JSGlobalPropertyCell* cell,
+                                                   JSFunction* function,
+                                                   String* name) {
   // ----------- S t a t e -------------
   //  -- rcx                 : name
   //  -- rsp[0]              : return address
   //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
   //  -- ...
   //  -- rsp[(argc + 1) * 8] : receiver
   // -----------------------------------
 
   // If object is not an array, bail out to regular call.
   if (!object->IsJSArray() || cell != NULL) return Heap::undefined_value();
@@ skipping 49 matching lines @@
   __ bind(&return_undefined);
   __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
   __ ret((argc + 1) * kPointerSize);
 
   __ bind(&call_builtin);
   __ TailCallExternalReference(ExternalReference(Builtins::c_ArrayPop),
                                argc + 1,
                                1);
 
   __ bind(&miss);
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return GetCode(function);
 }
 
 
-Object* CallStubCompiler::CompileStringCharAtCall(Object* object,
-                                                  JSObject* holder,
-                                                  JSGlobalPropertyCell* cell,
-                                                  JSFunction* function,
-                                                  String* name) {
+MaybeObject* CallStubCompiler::CompileStringCharAtCall(
+    Object* object,
+    JSObject* holder,
+    JSGlobalPropertyCell* cell,
+    JSFunction* function,
+    String* name) {
   // ----------- S t a t e -------------
   //  -- rcx                 : function name
   //  -- rsp[0]              : return address
   //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
   //  -- ...
   //  -- rsp[(argc + 1) * 8] : receiver
   // -----------------------------------
 
   // If object is not a string, bail out to regular call.
   if (!object->IsString() || cell != NULL) return Heap::undefined_value();
@@ skipping 39 matching lines @@
   __ ret((argc + 1) * kPointerSize);
 
   ICRuntimeCallHelper call_helper;
   char_at_generator.GenerateSlow(masm(), call_helper);
 
   __ bind(&index_out_of_range);
   __ LoadRoot(rax, Heap::kEmptyStringRootIndex);
   __ ret((argc + 1) * kPointerSize);
 
   __ bind(&miss);
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return GetCode(function);
 }
 
 
-Object* CallStubCompiler::CompileStringCharCodeAtCall(
+MaybeObject* CallStubCompiler::CompileStringCharCodeAtCall(
     Object* object,
     JSObject* holder,
     JSGlobalPropertyCell* cell,
     JSFunction* function,
     String* name) {
   // ----------- S t a t e -------------
   //  -- rcx                 : function name
   //  -- rsp[0]              : return address
   //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
   //  -- ...
@@ skipping 41 matching lines @@
   __ ret((argc + 1) * kPointerSize);
 
   ICRuntimeCallHelper call_helper;
   char_code_at_generator.GenerateSlow(masm(), call_helper);
 
   __ bind(&index_out_of_range);
   __ LoadRoot(rax, Heap::kNanValueRootIndex);
   __ ret((argc + 1) * kPointerSize);
 
   __ bind(&miss);
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return GetCode(function);
 }
 
 
-Object* CallStubCompiler::CompileStringFromCharCodeCall(
+MaybeObject* CallStubCompiler::CompileStringFromCharCodeCall(
     Object* object,
     JSObject* holder,
     JSGlobalPropertyCell* cell,
     JSFunction* function,
     String* name) {
   // ----------- S t a t e -------------
   //  -- rcx                 : function name
   //  -- rsp[0]              : return address
   //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
   //  -- ...
@@ skipping 40 matching lines @@
   ICRuntimeCallHelper call_helper;
   char_from_code_generator.GenerateSlow(masm(), call_helper);
 
   // Tail call the full function. We do not have to patch the receiver
   // because the function makes no use of it.
   __ bind(&slow);
   __ InvokeFunction(function, arguments(), JUMP_FUNCTION);
 
   __ bind(&miss);
   // rcx: function name.
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return (cell == NULL) ? GetCode(function) : GetCode(NORMAL, name);
 }
 
 
-Object* CallStubCompiler::CompileMathFloorCall(Object* object,
-                                               JSObject* holder,
-                                               JSGlobalPropertyCell* cell,
-                                               JSFunction* function,
-                                               String* name) {
+MaybeObject* CallStubCompiler::CompileMathFloorCall(Object* object,
+                                                    JSObject* holder,
+                                                    JSGlobalPropertyCell* cell,
+                                                    JSFunction* function,
+                                                    String* name) {
   // TODO(872): implement this.
   return Heap::undefined_value();
 }
 
 
-Object* CallStubCompiler::CompileMathAbsCall(Object* object,
-                                             JSObject* holder,
-                                             JSGlobalPropertyCell* cell,
-                                             JSFunction* function,
-                                             String* name) {
+MaybeObject* CallStubCompiler::CompileMathAbsCall(Object* object,
+                                                  JSObject* holder,
+                                                  JSGlobalPropertyCell* cell,
+                                                  JSFunction* function,
+                                                  String* name) {
   // ----------- S t a t e -------------
   //  -- rcx                 : function name
   //  -- rsp[0]              : return address
   //  -- rsp[(argc - n) * 8] : arg[n] (zero-based)
   //  -- ...
   //  -- rsp[(argc + 1) * 8] : receiver
   // -----------------------------------
 
   const int argc = arguments().immediate();
 
@@ skipping 70 matching lines @@
   __ movq(FieldOperand(rax, HeapNumber::kValueOffset), rbx);
   __ ret(2 * kPointerSize);
 
   // Tail call the full function. We do not have to patch the receiver
   // because the function makes no use of it.
   __ bind(&slow);
   __ InvokeFunction(function, arguments(), JUMP_FUNCTION);
 
   __ bind(&miss);
   // rcx: function name.
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return (cell == NULL) ? GetCode(function) : GetCode(NORMAL, name);
 }
 
 
-Object* CallStubCompiler::CompileCallInterceptor(JSObject* object,
-                                                 JSObject* holder,
-                                                 String* name) {
+MaybeObject* CallStubCompiler::CompileCallInterceptor(JSObject* object,
+                                                      JSObject* holder,
+                                                      String* name) {
   // ----------- S t a t e -------------
   // rcx                 : function name
   // rsp[0]              : return address
   // rsp[8]              : argument argc
   // rsp[16]             : argument argc - 1
   // ...
   // rsp[argc * 8]       : argument 1
   // rsp[(argc + 1) * 8] : argument 0 = receiver
   // -----------------------------------
   Label miss;
@@ skipping 35 matching lines @@
     __ movq(rdx, FieldOperand(rdx, GlobalObject::kGlobalReceiverOffset));
     __ movq(Operand(rsp, (argc + 1) * kPointerSize), rdx);
   }
 
   // Invoke the function.
   __ movq(rdi, rax);
   __ InvokeFunction(rdi, arguments(), JUMP_FUNCTION);
 
   // Handle load cache miss.
   __ bind(&miss);
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return GetCode(INTERCEPTOR, name);
 }
 
 
-Object* CallStubCompiler::CompileCallGlobal(JSObject* object,
-                                            GlobalObject* holder,
-                                            JSGlobalPropertyCell* cell,
-                                            JSFunction* function,
-                                            String* name) {
+MaybeObject* CallStubCompiler::CompileCallGlobal(JSObject* object,
+                                                 GlobalObject* holder,
+                                                 JSGlobalPropertyCell* cell,
+                                                 JSFunction* function,
+                                                 String* name) {
   // ----------- S t a t e -------------
   // rcx                 : function name
   // rsp[0]              : return address
   // rsp[8]              : argument argc
   // rsp[16]             : argument argc - 1
   // ...
   // rsp[argc * 8]       : argument 1
   // rsp[(argc + 1) * 8] : argument 0 = receiver
   // -----------------------------------
 
   SharedFunctionInfo* function_info = function->shared();
   if (function_info->HasCustomCallGenerator()) {
     const int id = function_info->custom_call_generator_id();
-    Object* result = CompileCustomCall(
+    MaybeObject* maybe_result = CompileCustomCall(
         id, object, holder, cell, function, name);
+    Object* result;
+    if (!maybe_result->ToObject(&result)) return maybe_result;
     // undefined means bail out to regular compiler.
     if (!result->IsUndefined()) return result;
   }
 
   Label miss;
 
   GenerateNameCheck(name, &miss);
 
   // Get the number of arguments.
   const int argc = arguments().immediate();
@@ skipping 15 matching lines @@
   __ IncrementCounter(&Counters::call_global_inline, 1);
   ASSERT(function->is_compiled());
   Handle<Code> code(function->code());
   ParameterCount expected(function->shared()->formal_parameter_count());
   __ InvokeCode(code, expected, arguments(),
                 RelocInfo::CODE_TARGET, JUMP_FUNCTION);
 
   // Handle call cache miss.
   __ bind(&miss);
   __ IncrementCounter(&Counters::call_global_inline_miss, 1);
-  Object* obj = GenerateMissBranch();
-  if (obj->IsFailure()) return obj;
+  Object* obj;
+  { MaybeObject* maybe_obj = GenerateMissBranch();
+    if (!maybe_obj->ToObject(&obj)) return maybe_obj;
+  }
 
   // Return the generated code.
   return GetCode(NORMAL, name);
 }
 
 
-Object* LoadStubCompiler::CompileLoadCallback(String* name,
-                                              JSObject* object,
-                                              JSObject* holder,
-                                              AccessorInfo* callback) {
+MaybeObject* LoadStubCompiler::CompileLoadCallback(String* name,
+                                                   JSObject* object,
+                                                   JSObject* holder,
+                                                   AccessorInfo* callback) {
   // ----------- S t a t e -------------
   //  -- rax    : receiver
   //  -- rcx    : name
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   Failure* failure = Failure::InternalError();
   bool success = GenerateLoadCallback(object, holder, rax, rcx, rbx, rdx, rdi,
                                       callback, name, &miss, &failure);
   if (!success) {
     miss.Unuse();
     return failure;
   }
 
   __ bind(&miss);
   GenerateLoadMiss(masm(), Code::LOAD_IC);
 
   // Return the generated code.
   return GetCode(CALLBACKS, name);
 }
 
 
-Object* LoadStubCompiler::CompileLoadConstant(JSObject* object,
-                                              JSObject* holder,
-                                              Object* value,
-                                              String* name) {
+MaybeObject* LoadStubCompiler::CompileLoadConstant(JSObject* object,
+                                                   JSObject* holder,
+                                                   Object* value,
+                                                   String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : receiver
   //  -- rcx    : name
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   GenerateLoadConstant(object, holder, rax, rbx, rdx, rdi, value, name, &miss);
   __ bind(&miss);
   GenerateLoadMiss(masm(), Code::LOAD_IC);
 
   // Return the generated code.
   return GetCode(CONSTANT_FUNCTION, name);
 }
 
 
-Object* LoadStubCompiler::CompileLoadNonexistent(String* name,
-                                                 JSObject* object,
-                                                 JSObject* last) {
+MaybeObject* LoadStubCompiler::CompileLoadNonexistent(String* name,
+                                                      JSObject* object,
+                                                      JSObject* last) {
   // ----------- S t a t e -------------
   //  -- rax    : receiver
   //  -- rcx    : name
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   // Chech that receiver is not a smi.
   __ JumpIfSmi(rax, &miss);
 
   // Check the maps of the full prototype chain. Also check that
   // global property cells up to (but not including) the last object
   // in the prototype chain are empty.
   CheckPrototypes(object, rax, last, rbx, rdx, rdi, name, &miss);
 
   // If the last object in the prototype chain is a global object,
   // check that the global property cell is empty.
   if (last->IsGlobalObject()) {
-    Object* cell = GenerateCheckPropertyCell(masm(),
-                                             GlobalObject::cast(last),
-                                             name,
-                                             rdx,
-                                             &miss);
+    MaybeObject* cell = GenerateCheckPropertyCell(masm(),
+                                                  GlobalObject::cast(last),
+                                                  name,
+                                                  rdx,
+                                                  &miss);
     if (cell->IsFailure()) {
       miss.Unuse();
       return cell;
     }
   }
 
   // Return undefined if maps of the full prototype chain are still the
   // same and no global property with this name contains a value.
   __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
   __ ret(0);
 
   __ bind(&miss);
   GenerateLoadMiss(masm(), Code::LOAD_IC);
 
   // Return the generated code.
   return GetCode(NONEXISTENT, Heap::empty_string());
 }
 
 
-Object* LoadStubCompiler::CompileLoadField(JSObject* object,
-                                           JSObject* holder,
-                                           int index,
-                                           String* name) {
+MaybeObject* LoadStubCompiler::CompileLoadField(JSObject* object,
+                                                JSObject* holder,
+                                                int index,
+                                                String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : receiver
   //  -- rcx    : name
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   GenerateLoadField(object, holder, rax, rbx, rdx, rdi, index, name, &miss);
   __ bind(&miss);
   GenerateLoadMiss(masm(), Code::LOAD_IC);
 
   // Return the generated code.
   return GetCode(FIELD, name);
 }
 
 
-Object* LoadStubCompiler::CompileLoadInterceptor(JSObject* receiver,
-                                                 JSObject* holder,
-                                                 String* name) {
+MaybeObject* LoadStubCompiler::CompileLoadInterceptor(JSObject* receiver,
+                                                      JSObject* holder,
+                                                      String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : receiver
   //  -- rcx    : name
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   LookupResult lookup;
   LookupPostInterceptor(holder, name, &lookup);
 
@@ skipping 11 matching lines @@
                           &miss);
 
   __ bind(&miss);
   GenerateLoadMiss(masm(), Code::LOAD_IC);
 
   // Return the generated code.
   return GetCode(INTERCEPTOR, name);
 }
 
 
-Object* LoadStubCompiler::CompileLoadGlobal(JSObject* object,
-                                            GlobalObject* holder,
-                                            JSGlobalPropertyCell* cell,
-                                            String* name,
-                                            bool is_dont_delete) {
+MaybeObject* LoadStubCompiler::CompileLoadGlobal(JSObject* object,
+                                                 GlobalObject* holder,
+                                                 JSGlobalPropertyCell* cell,
+                                                 String* name,
+                                                 bool is_dont_delete) {
   // ----------- S t a t e -------------
   //  -- rax    : receiver
   //  -- rcx    : name
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   // If the object is the holder then we know that it's a global
   // object which can only happen for contextual loads. In this case,
   // the receiver cannot be a smi.
@@ skipping 23 matching lines @@
 
   __ bind(&miss);
   __ IncrementCounter(&Counters::named_load_global_stub_miss, 1);
   GenerateLoadMiss(masm(), Code::LOAD_IC);
 
   // Return the generated code.
   return GetCode(NORMAL, name);
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadCallback(String* name,
-                                                   JSObject* receiver,
-                                                   JSObject* holder,
-                                                   AccessorInfo* callback) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadCallback(
+    String* name,
+    JSObject* receiver,
+    JSObject* holder,
+    AccessorInfo* callback) {
   // ----------- S t a t e -------------
   //  -- rax     : key
   //  -- rdx     : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   Label miss;
 
   __ IncrementCounter(&Counters::keyed_load_callback, 1);
 
   // Check that the name has not changed.
@@ skipping 10 matching lines @@
 
   __ bind(&miss);
   __ DecrementCounter(&Counters::keyed_load_callback, 1);
   GenerateLoadMiss(masm(), Code::KEYED_LOAD_IC);
 
   // Return the generated code.
   return GetCode(CALLBACKS, name);
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadArrayLength(String* name) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadArrayLength(String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : key
   //  -- rdx    : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   Label miss;
 
   __ IncrementCounter(&Counters::keyed_load_array_length, 1);
 
   // Check that the name has not changed.
   __ Cmp(rax, Handle<String>(name));
   __ j(not_equal, &miss);
 
   GenerateLoadArrayLength(masm(), rdx, rcx, &miss);
   __ bind(&miss);
   __ DecrementCounter(&Counters::keyed_load_array_length, 1);
   GenerateLoadMiss(masm(), Code::KEYED_LOAD_IC);
 
   // Return the generated code.
   return GetCode(CALLBACKS, name);
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadConstant(String* name,
-                                                   JSObject* receiver,
-                                                   JSObject* holder,
-                                                   Object* value) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadConstant(String* name,
+                                                        JSObject* receiver,
+                                                        JSObject* holder,
+                                                        Object* value) {
   // ----------- S t a t e -------------
   //  -- rax    : key
   //  -- rdx    : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   Label miss;
 
   __ IncrementCounter(&Counters::keyed_load_constant_function, 1);
 
   // Check that the name has not changed.
   __ Cmp(rax, Handle<String>(name));
   __ j(not_equal, &miss);
 
   GenerateLoadConstant(receiver, holder, rdx, rbx, rcx, rdi,
                        value, name, &miss);
   __ bind(&miss);
   __ DecrementCounter(&Counters::keyed_load_constant_function, 1);
   GenerateLoadMiss(masm(), Code::KEYED_LOAD_IC);
 
   // Return the generated code.
   return GetCode(CONSTANT_FUNCTION, name);
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadFunctionPrototype(String* name) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadFunctionPrototype(String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : key
   //  -- rdx    : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   Label miss;
 
   __ IncrementCounter(&Counters::keyed_load_function_prototype, 1);
 
   // Check that the name has not changed.
   __ Cmp(rax, Handle<String>(name));
   __ j(not_equal, &miss);
 
   GenerateLoadFunctionPrototype(masm(), rdx, rcx, rbx, &miss);
   __ bind(&miss);
   __ DecrementCounter(&Counters::keyed_load_function_prototype, 1);
   GenerateLoadMiss(masm(), Code::KEYED_LOAD_IC);
 
   // Return the generated code.
   return GetCode(CALLBACKS, name);
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadInterceptor(JSObject* receiver,
-                                                      JSObject* holder,
-                                                      String* name) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadInterceptor(JSObject* receiver,
+                                                           JSObject* holder,
+                                                           String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : key
   //  -- rdx    : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   Label miss;
 
   __ IncrementCounter(&Counters::keyed_load_interceptor, 1);
 
   // Check that the name has not changed.
@@ skipping 14 matching lines @@
                           &miss);
   __ bind(&miss);
   __ DecrementCounter(&Counters::keyed_load_interceptor, 1);
   GenerateLoadMiss(masm(), Code::KEYED_LOAD_IC);
 
   // Return the generated code.
   return GetCode(INTERCEPTOR, name);
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadStringLength(String* name) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadStringLength(String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : key
   //  -- rdx    : receiver
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   __ IncrementCounter(&Counters::keyed_load_string_length, 1);
 
   // Check that the name has not changed.
   __ Cmp(rax, Handle<String>(name));
   __ j(not_equal, &miss);
 
   GenerateLoadStringLength(masm(), rdx, rcx, rbx, &miss);
   __ bind(&miss);
   __ DecrementCounter(&Counters::keyed_load_string_length, 1);
   GenerateLoadMiss(masm(), Code::KEYED_LOAD_IC);
 
   // Return the generated code.
   return GetCode(CALLBACKS, name);
 }
 
 
-Object* StoreStubCompiler::CompileStoreCallback(JSObject* object,
-                                                AccessorInfo* callback,
-                                                String* name) {
+MaybeObject* StoreStubCompiler::CompileStoreCallback(JSObject* object,
+                                                     AccessorInfo* callback,
+                                                     String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : value
   //  -- rcx    : name
   //  -- rdx    : receiver
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   // Check that the object isn't a smi.
   __ JumpIfSmi(rdx, &miss);
@@ skipping 27 matching lines @@
   // Handle store cache miss.
   __ bind(&miss);
   Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Miss));
   __ Jump(ic, RelocInfo::CODE_TARGET);
 
   // Return the generated code.
   return GetCode(CALLBACKS, name);
 }
 
 
-Object* StoreStubCompiler::CompileStoreField(JSObject* object,
-                                             int index,
-                                             Map* transition,
-                                             String* name) {
+MaybeObject* StoreStubCompiler::CompileStoreField(JSObject* object,
+                                                  int index,
+                                                  Map* transition,
+                                                  String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : value
   //  -- rcx    : name
   //  -- rdx    : receiver
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   // Generate store field code.  Preserves receiver and name on jump to miss.
   GenerateStoreField(masm(),
                      object,
                      index,
                      transition,
                      rdx, rcx, rbx,
                      &miss);
 
   // Handle store cache miss.
   __ bind(&miss);
   Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Miss));
   __ Jump(ic, RelocInfo::CODE_TARGET);
 
   // Return the generated code.
   return GetCode(transition == NULL ? FIELD : MAP_TRANSITION, name);
 }
 
 
-Object* StoreStubCompiler::CompileStoreInterceptor(JSObject* receiver,
-                                                   String* name) {
+MaybeObject* StoreStubCompiler::CompileStoreInterceptor(JSObject* receiver,
+                                                        String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : value
   //  -- rcx    : name
   //  -- rdx    : receiver
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   // Check that the object isn't a smi.
   __ JumpIfSmi(rdx, &miss);
@@ skipping 26 matching lines @@
   // Handle store cache miss.
   __ bind(&miss);
   Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Miss));
   __ Jump(ic, RelocInfo::CODE_TARGET);
 
   // Return the generated code.
   return GetCode(INTERCEPTOR, name);
 }
 
 
-Object* StoreStubCompiler::CompileStoreGlobal(GlobalObject* object,
-                                              JSGlobalPropertyCell* cell,
-                                              String* name) {
+MaybeObject* StoreStubCompiler::CompileStoreGlobal(GlobalObject* object,
+                                                   JSGlobalPropertyCell* cell,
+                                                   String* name) {
   // ----------- S t a t e -------------
   //  -- rax    : value
   //  -- rcx    : name
   //  -- rdx    : receiver
   //  -- rsp[0] : return address
   // -----------------------------------
   Label miss;
 
   // Check that the map of the global has not changed.
   __ Cmp(FieldOperand(rdx, HeapObject::kMapOffset),
@@ skipping 12 matching lines @@
   __ bind(&miss);
   __ IncrementCounter(&Counters::named_store_global_inline_miss, 1);
   Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Miss));
   __ Jump(ic, RelocInfo::CODE_TARGET);
 
   // Return the generated code.
   return GetCode(NORMAL, name);
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadField(String* name,
-                                                JSObject* receiver,
-                                                JSObject* holder,
-                                                int index) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadField(String* name,
+                                                     JSObject* receiver,
+                                                     JSObject* holder,
+                                                     int index) {
   // ----------- S t a t e -------------
   //  -- rax     : key
   //  -- rdx     : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   Label miss;
 
   __ IncrementCounter(&Counters::keyed_load_field, 1);
 
   // Check that the name has not changed.
   __ Cmp(rax, Handle<String>(name));
   __ j(not_equal, &miss);
 
   GenerateLoadField(receiver, holder, rdx, rbx, rcx, rdi, index, name, &miss);
 
   __ bind(&miss);
   __ DecrementCounter(&Counters::keyed_load_field, 1);
   GenerateLoadMiss(masm(), Code::KEYED_LOAD_IC);
 
   // Return the generated code.
   return GetCode(FIELD, name);
 }
 
 
-Object* KeyedStoreStubCompiler::CompileStoreField(JSObject* object,
-                                                  int index,
-                                                  Map* transition,
-                                                  String* name) {
+MaybeObject* KeyedStoreStubCompiler::CompileStoreField(JSObject* object,
+                                                       int index,
+                                                       Map* transition,
+                                                       String* name) {
   // ----------- S t a t e -------------
   //  -- rax     : value
   //  -- rcx     : key
   //  -- rdx     : receiver
   //  -- rsp[0]  : return address
   // -----------------------------------
   Label miss;
 
   __ IncrementCounter(&Counters::keyed_store_field, 1);
 
@@ skipping 217 matching lines @@
 #ifdef _WIN64
   // We need to prepare a slot for result handle on stack and put
   // a pointer to it into 1st arg register.
   __ push(Immediate(0));
   __ movq(rcx, rsp);
 #endif
   // Emitting a stub call may try to allocate (if the code is not
   // already generated).  Do not allow the assembler to perform a
   // garbage collection but instead return the allocation failure
   // object.
-  Object* result = masm()->TryCallStub(&stub);
+  MaybeObject* result = masm()->TryCallStub(&stub);
   if (result->IsFailure()) {
     *failure = Failure::cast(result);
     return false;
   }
 #ifdef _WIN64
   // Discard allocated slot.
   __ addq(rsp, Immediate(kPointerSize));
 #endif
   __ LeaveInternalFrame();
 
@@ skipping 35 matching lines @@
 
     // Only global objects and objects that do not require access
     // checks are allowed in stubs.
     ASSERT(current->IsJSGlobalProxy() || !current->IsAccessCheckNeeded());
 
     JSObject* prototype = JSObject::cast(current->GetPrototype());
     if (!current->HasFastProperties() &&
         !current->IsJSGlobalObject() &&
         !current->IsJSGlobalProxy()) {
       if (!name->IsSymbol()) {
-        Object* lookup_result = Heap::LookupSymbol(name);
+        MaybeObject* lookup_result = Heap::LookupSymbol(name);
         if (lookup_result->IsFailure()) {
           set_failure(Failure::cast(lookup_result));
           return reg;
         } else {
-          name = String::cast(lookup_result);
+          name = String::cast(lookup_result->ToObjectUnchecked());
         }
       }
       ASSERT(current->property_dictionary()->FindEntry(name) ==
              StringDictionary::kNotFound);
 
       GenerateDictionaryNegativeLookup(masm(),
                                        miss,
                                        reg,
                                        name,
                                        scratch1,
@@ skipping 61 matching lines @@
   if (current->IsJSGlobalProxy()) {
     __ CheckAccessGlobalProxy(reg, scratch1, miss);
   }
 
   // If we've skipped any global objects, it's not enough to verify
   // that their maps haven't changed.  We also need to check that the
   // property cell for the property is still empty.
   current = object;
   while (current != holder) {
     if (current->IsGlobalObject()) {
-      Object* cell = GenerateCheckPropertyCell(masm(),
-                                               GlobalObject::cast(current),
-                                               name,
-                                               scratch1,
-                                               miss);
+      MaybeObject* cell = GenerateCheckPropertyCell(masm(),
+                                                    GlobalObject::cast(current),
+                                                    name,
+                                                    scratch1,
+                                                    miss);
       if (cell->IsFailure()) {
         set_failure(Failure::cast(cell));
         return reg;
       }
     }
     current = JSObject::cast(current->GetPrototype());
   }
 
   // Return the register containing the holder.
   return reg;
@@ skipping 41 matching lines @@
                       scratch1, scratch2, scratch3, name, miss);
 
   // Return the constant value.
   __ Move(rax, Handle<Object>(value));
   __ ret(0);
 }
 
 
 // Specialized stub for constructing objects from functions which only have only
 // simple assignments of the form this.x = ...; in their body.
-Object* ConstructStubCompiler::CompileConstructStub(
+MaybeObject* ConstructStubCompiler::CompileConstructStub(
     SharedFunctionInfo* shared) {
   // ----------- S t a t e -------------
   //  -- rax : argc
   //  -- rdi : constructor
   //  -- rsp[0] : return address
   //  -- rsp[4] : last argument
   // -----------------------------------
   Label generic_stub_call;
 
   // Use r8 for holding undefined which is used in several places below.
@@ skipping 112 matching lines @@
   // Return the generated code.
   return GetCode();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64