Always check global property cells for readonliness before storing.

src/arm/stub-cache-arm.cc

 // Copyright 2012 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 399 matching lines @@
                                                  Register receiver,
                                                  Register scratch1,
                                                  Register scratch2,
                                                  Label* miss_label) {
   __ TryGetFunctionPrototype(receiver, scratch1, scratch2, miss_label);
   __ mov(r0, scratch1);
   __ Ret();
 }
 
 
+// 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 void GenerateCheckPropertyCell(MacroAssembler* masm,
+                                      Handle<GlobalObject> global,
+                                      Handle<Name> name,
+                                      Register scratch,
+                                      Label* miss) {
+  Handle<JSGlobalPropertyCell> cell =
+      GlobalObject::EnsurePropertyCell(global, name);
+  ASSERT(cell->value()->IsTheHole());
+  __ mov(scratch, Operand(cell));
+  __ ldr(scratch,
+         FieldMemOperand(scratch, JSGlobalPropertyCell::kValueOffset));
+  __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
+  __ cmp(scratch, ip);
+  __ b(ne, miss);
+}
+
+
 // Generate StoreField code, value is passed in r0 register.
 // When leaving generated code after success, the receiver_reg and name_reg
 // may be clobbered.  Upon branch to miss_label, the receiver and name
 // registers have their original values.
 void StubCompiler::GenerateStoreField(MacroAssembler* masm,
                                       Handle<JSObject> object,
                                       LookupResult* lookup,
                                       Handle<Map> transition,
                                       Handle<Name> name,
                                       Register receiver_reg,
@@ skipping 29 matching lines @@
       do {
         holder = JSObject::cast(holder->GetPrototype());
       } while (holder->GetPrototype()->IsJSObject());
     }
     Register holder_reg = CheckPrototypes(
         object, receiver_reg, Handle<JSObject>(holder), name_reg,
         scratch1, scratch2, name, miss_restore_name);
     // If no property was found, and the holder (the last object in the
     // prototype chain) is in slow mode, we need to do a negative lookup on the
     // holder.
-    if (lookup->holder() == *object &&
-        !holder->HasFastProperties() &&
-        !holder->IsJSGlobalProxy() &&
-        !holder->IsJSGlobalObject()) {
-      GenerateDictionaryNegativeLookup(
-          masm, miss_restore_name, holder_reg, name, scratch1, scratch2);
+    if (lookup->holder() == *object) {
+      if (holder->IsJSGlobalObject()) {
+        GenerateCheckPropertyCell(
+            masm,
+            Handle<GlobalObject>(GlobalObject::cast(holder)),
+            name,
+            scratch1,
+            miss_restore_name);
+      } else if (!holder->HasFastProperties() && !holder->IsJSGlobalProxy()) {
+        GenerateDictionaryNegativeLookup(
+            masm, miss_restore_name, holder_reg, name, scratch1, scratch2);
+      }
     }
   }
 
   // Stub never generated for non-global objects that require access
   // checks.
   ASSERT(object->IsJSGlobalProxy() || !object->IsAccessCheckNeeded());
 
   // Perform map transition for the receiver if necessary.
   if (!transition.is_null() && (object->map()->unused_property_fields() == 0)) {
     // The properties must be extended before we can store the value.
@@ skipping 434 matching lines @@
     __ b(ne, interceptor_succeeded);
   }
 
   StubCompiler* stub_compiler_;
   const ParameterCount& arguments_;
   Register name_;
   Code::ExtraICState extra_ic_state_;
 };
 
 
-// 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 void GenerateCheckPropertyCell(MacroAssembler* masm,
-                                      Handle<GlobalObject> global,
-                                      Handle<Name> name,
-                                      Register scratch,
-                                      Label* miss) {
-  Handle<JSGlobalPropertyCell> cell =
-      GlobalObject::EnsurePropertyCell(global, name);
-  ASSERT(cell->value()->IsTheHole());
-  __ mov(scratch, Operand(cell));
-  __ ldr(scratch,
-         FieldMemOperand(scratch, JSGlobalPropertyCell::kValueOffset));
-  __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
-  __ cmp(scratch, ip);
-  __ b(ne, miss);
-}
-
-
 // Calls GenerateCheckPropertyCell for each global object in the prototype chain
 // from object to (but not including) holder.
 static void GenerateCheckPropertyCells(MacroAssembler* masm,
                                        Handle<JSObject> object,
                                        Handle<JSObject> holder,
                                        Handle<Name> name,
                                        Register scratch,
                                        Label* miss) {
   Handle<JSObject> current = object;
   while (!current.is_identical_to(holder)) {
@@ skipping 2889 matching lines @@
     TailCallBuiltin(masm, Builtins::kKeyedStoreIC_Slow);
   }
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM