Make Failure inherit from MaybeObject instead of Object.

src/arm/stub-cache-arm.cc

Index: src/arm/stub-cache-arm.cc
===================================================================
--- src/arm/stub-cache-arm.cc	(revision 5696)
+++ src/arm/stub-cache-arm.cc	(working copy)
@@ -834,13 +834,16 @@
 // 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());
   __ mov(scratch, Operand(Handle<Object>(cell)));
@@ -894,12 +897,12 @@
         !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) ==
@@ -974,11 +977,11 @@
   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;
@@ -1281,18 +1284,21 @@
 }
 
 
-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::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 -------------
   //  -- r2    : name
   //  -- lr    : return address
@@ -1317,19 +1323,21 @@
 
   // 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 -------------
   //  -- r2    : name
   //  -- lr    : return address
@@ -1361,19 +1369,21 @@
 
   // 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(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 -------------
   //  -- r2    : name
   //  -- lr    : return address
@@ -1405,15 +1415,17 @@
 
   // 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(function);
 }
 
 
-Object* CallStubCompiler::CompileStringCharCodeAtCall(
+MaybeObject* CallStubCompiler::CompileStringCharCodeAtCall(
     Object* object,
     JSObject* holder,
     JSGlobalPropertyCell* cell,
@@ -1477,19 +1489,22 @@
   __ Ret();
 
   __ 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 -------------
   //  -- r2                     : function name
   //  -- lr                     : return address
@@ -1551,15 +1566,17 @@
   __ Ret();
 
   __ 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,
@@ -1625,29 +1642,31 @@
 
   __ bind(&miss);
   // r2: 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 -------------
   //  -- r2                     : function name
   //  -- lr                     : return address
@@ -1737,19 +1756,21 @@
 
   __ bind(&miss);
   // r2: 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::CompileCallConstant(Object* object,
-                                              JSObject* holder,
-                                              JSFunction* function,
-                                              String* name,
-                                              CheckType check) {
+MaybeObject* CallStubCompiler::CompileCallConstant(Object* object,
+                                                   JSObject* holder,
+                                                   JSFunction* function,
+                                                   String* name,
+                                                   CheckType check) {
   // ----------- S t a t e -------------
   //  -- r2    : name
   //  -- lr    : return address
@@ -1757,8 +1778,10 @@
   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;
@@ -1891,17 +1914,19 @@
   }
 
   __ 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::CompileCallInterceptor(JSObject* object,
-                                                 JSObject* holder,
-                                                 String* name) {
+MaybeObject* CallStubCompiler::CompileCallInterceptor(JSObject* object,
+                                                      JSObject* holder,
+                                                      String* name) {
   // ----------- S t a t e -------------
   //  -- r2    : name
   //  -- lr    : return address
@@ -1941,19 +1966,21 @@
 
   // 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(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 -------------
   //  -- r2    : name
   //  -- lr    : return address
@@ -1962,8 +1989,10 @@
   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;
   }
@@ -2000,18 +2029,20 @@
   // Handle call cache miss.
   __ bind(&miss);
   __ IncrementCounter(&Counters::call_global_inline_miss, 1, r1, r3);
-  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* 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 -------------
   //  -- r0    : value
   //  -- r1    : receiver
@@ -2035,9 +2066,9 @@
 }
 
 
-Object* StoreStubCompiler::CompileStoreCallback(JSObject* object,
-                                                AccessorInfo* callback,
-                                                String* name) {
+MaybeObject* StoreStubCompiler::CompileStoreCallback(JSObject* object,
+                                                     AccessorInfo* callback,
+                                                     String* name) {
   // ----------- S t a t e -------------
   //  -- r0    : value
   //  -- r1    : receiver
@@ -2083,8 +2114,8 @@
 }
 
 
-Object* StoreStubCompiler::CompileStoreInterceptor(JSObject* receiver,
-                                                   String* name) {
+MaybeObject* StoreStubCompiler::CompileStoreInterceptor(JSObject* receiver,
+                                                        String* name) {
   // ----------- S t a t e -------------
   //  -- r0    : value
   //  -- r1    : receiver
@@ -2128,9 +2159,9 @@
 }
 
 
-Object* StoreStubCompiler::CompileStoreGlobal(GlobalObject* object,
-                                              JSGlobalPropertyCell* cell,
-                                              String* name) {
+MaybeObject* StoreStubCompiler::CompileStoreGlobal(GlobalObject* object,
+                                                   JSGlobalPropertyCell* cell,
+                                                   String* name) {
   // ----------- S t a t e -------------
   //  -- r0    : value
   //  -- r1    : receiver
@@ -2162,9 +2193,9 @@
 }
 
 
-Object* LoadStubCompiler::CompileLoadNonexistent(String* name,
-                                                 JSObject* object,
-                                                 JSObject* last) {
+MaybeObject* LoadStubCompiler::CompileLoadNonexistent(String* name,
+                                                      JSObject* object,
+                                                      JSObject* last) {
   // ----------- S t a t e -------------
   //  -- r0    : receiver
   //  -- lr    : return address
@@ -2181,11 +2212,11 @@
   // 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,
-                                             r1,
-                                             &miss);
+    MaybeObject* cell = GenerateCheckPropertyCell(masm(),
+                                                  GlobalObject::cast(last),
+                                                  name,
+                                                  r1,
+                                                  &miss);
     if (cell->IsFailure()) {
       miss.Unuse();
       return cell;
@@ -2205,10 +2236,10 @@
 }
 
 
-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 -------------
   //  -- r0    : receiver
   //  -- r2    : name
@@ -2225,10 +2256,10 @@
 }
 
 
-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 -------------
   //  -- r0    : receiver
   //  -- r2    : name
@@ -2252,10 +2283,10 @@
 }
 
 
-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 -------------
   //  -- r0    : receiver
   //  -- r2    : name
@@ -2272,9 +2303,9 @@
 }
 
 
-Object* LoadStubCompiler::CompileLoadInterceptor(JSObject* object,
-                                                 JSObject* holder,
-                                                 String* name) {
+MaybeObject* LoadStubCompiler::CompileLoadInterceptor(JSObject* object,
+                                                      JSObject* holder,
+                                                      String* name) {
   // ----------- S t a t e -------------
   //  -- r0    : receiver
   //  -- r2    : name
@@ -2302,11 +2333,11 @@
 }
 
 
-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 -------------
   //  -- r0    : receiver
   //  -- r2    : name
@@ -2349,10 +2380,10 @@
 }
 
 
-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 -------------
   //  -- lr    : return address
   //  -- r0    : key
@@ -2372,10 +2403,11 @@
 }
 
 
-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 -------------
   //  -- lr    : return address
   //  -- r0    : key
@@ -2402,10 +2434,10 @@
 }
 
 
-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 -------------
   //  -- lr    : return address
   //  -- r0    : key
@@ -2426,9 +2458,9 @@
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadInterceptor(JSObject* receiver,
-                                                      JSObject* holder,
-                                                      String* name) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadInterceptor(JSObject* receiver,
+                                                           JSObject* holder,
+                                                           String* name) {
   // ----------- S t a t e -------------
   //  -- lr    : return address
   //  -- r0    : key
@@ -2459,7 +2491,7 @@
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadArrayLength(String* name) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadArrayLength(String* name) {
   // ----------- S t a t e -------------
   //  -- lr    : return address
   //  -- r0    : key
@@ -2479,7 +2511,7 @@
 }
 
 
-Object* KeyedLoadStubCompiler::CompileLoadStringLength(String* name) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadStringLength(String* name) {
   // ----------- S t a t e -------------
   //  -- lr    : return address
   //  -- r0    : key
@@ -2503,7 +2535,7 @@
 
 
 // TODO(1224671): implement the fast case.
-Object* KeyedLoadStubCompiler::CompileLoadFunctionPrototype(String* name) {
+MaybeObject* KeyedLoadStubCompiler::CompileLoadFunctionPrototype(String* name) {
   // ----------- S t a t e -------------
   //  -- lr    : return address
   //  -- r0    : key
@@ -2515,10 +2547,10 @@
 }
 
 
-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 -------------
   //  -- r0    : value
   //  -- r1    : key
@@ -2553,7 +2585,7 @@
 }
 
 
-Object* ConstructStubCompiler::CompileConstructStub(
+MaybeObject* ConstructStubCompiler::CompileConstructStub(
     SharedFunctionInfo* shared) {
   // ----------- S t a t e -------------
   //  -- r0    : argc