Fix direct loading of global function prototypes:

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 198 matching lines @@
   __ movq(prototype, Operand(prototype, Context::SlotOffset(index)));
   // Load the initial map.  The global functions all have initial maps.
   __ movq(prototype,
              FieldOperand(prototype, JSFunction::kPrototypeOrInitialMapOffset));
   // Load the prototype from the initial map.
   __ movq(prototype, FieldOperand(prototype, Map::kPrototypeOffset));
 }
 
 
 void StubCompiler::GenerateDirectLoadGlobalFunctionPrototype(
-    MacroAssembler* masm, int index, Register prototype) {
+    MacroAssembler* masm, int index, Register prototype, Label* miss) {
+  // Check we're still in the same context.
+  __ Move(prototype, Top::global());
+  __ cmpq(Operand(rsi, Context::SlotOffset(Context::GLOBAL_INDEX)),
+          prototype);
+  __ j(not_equal, miss);
   // Get the global function with the given index.
   JSFunction* function = JSFunction::cast(Top::global_context()->get(index));
   // Load its initial map. The global functions all have initial maps.
   __ Move(prototype, Handle<Map>(function->initial_map()));
   // Load the prototype from the initial map.
   __ movq(prototype, FieldOperand(prototype, Map::kPrototypeOffset));
 }
 
 
 // Load a fast property out of a holder object (src). In-object properties
@@ skipping 727 matching lines @@
     case STRING_CHECK:
       if (!function->IsBuiltin()) {
         // Calling non-builtins with a value as receiver requires boxing.
         __ jmp(&miss);
       } else {
         // Check that the object is a two-byte string or a symbol.
         __ CmpObjectType(rdx, FIRST_NONSTRING_TYPE, rax);
         __ j(above_equal, &miss);
         // Check that the maps starting from the prototype haven't changed.
         GenerateDirectLoadGlobalFunctionPrototype(
-            masm(), Context::STRING_FUNCTION_INDEX, rax);
+            masm(), Context::STRING_FUNCTION_INDEX, rax, &miss);
         CheckPrototypes(JSObject::cast(object->GetPrototype()), rax, holder,
                         rbx, rdx, rdi, name, &miss);
       }
       break;
 
     case NUMBER_CHECK: {
       if (!function->IsBuiltin()) {
         // Calling non-builtins with a value as receiver requires boxing.
         __ jmp(&miss);
       } else {
         Label fast;
         // Check that the object is a smi or a heap number.
         __ JumpIfSmi(rdx, &fast);
         __ CmpObjectType(rdx, HEAP_NUMBER_TYPE, rax);
         __ j(not_equal, &miss);
         __ bind(&fast);
         // Check that the maps starting from the prototype haven't changed.
         GenerateDirectLoadGlobalFunctionPrototype(
-            masm(), Context::NUMBER_FUNCTION_INDEX, rax);
+            masm(), Context::NUMBER_FUNCTION_INDEX, rax, &miss);
         CheckPrototypes(JSObject::cast(object->GetPrototype()), rax, holder,
                         rbx, rdx, rdi, name, &miss);
       }
       break;
     }
 
     case BOOLEAN_CHECK: {
       if (!function->IsBuiltin()) {
         // Calling non-builtins with a value as receiver requires boxing.
         __ jmp(&miss);
       } else {
         Label fast;
         // Check that the object is a boolean.
         __ CompareRoot(rdx, Heap::kTrueValueRootIndex);
         __ j(equal, &fast);
         __ CompareRoot(rdx, Heap::kFalseValueRootIndex);
         __ j(not_equal, &miss);
         __ bind(&fast);
         // Check that the maps starting from the prototype haven't changed.
         GenerateDirectLoadGlobalFunctionPrototype(
-            masm(), Context::BOOLEAN_FUNCTION_INDEX, rax);
+            masm(), Context::BOOLEAN_FUNCTION_INDEX, rax, &miss);
         CheckPrototypes(JSObject::cast(object->GetPrototype()), rax, holder,
                         rbx, rdx, rdi, name, &miss);
       }
       break;
     }
 
     default:
       UNREACHABLE();
   }
 
@@ skipping 333 matching lines @@
   const int argc = arguments().immediate();
 
   Label miss;
   Label index_out_of_range;
 
   GenerateNameCheck(name, &miss);
 
   // Check that the maps starting from the prototype haven't changed.
   GenerateDirectLoadGlobalFunctionPrototype(masm(),
                                             Context::STRING_FUNCTION_INDEX,
-                                            rax);
+                                            rax,
+                                            &miss);
   ASSERT(object != holder);
   CheckPrototypes(JSObject::cast(object->GetPrototype()), rax, holder,
                   rbx, rdx, rdi, name, &miss);
 
   Register receiver = rax;
   Register index = rdi;
   Register scratch1 = rbx;
   Register scratch2 = rdx;
   Register result = rax;
   __ movq(receiver, Operand(rsp, (argc + 1) * kPointerSize));
@@ skipping 50 matching lines @@
 
   const int argc = arguments().immediate();
 
   Label miss;
   Label index_out_of_range;
   GenerateNameCheck(name, &miss);
 
   // Check that the maps starting from the prototype haven't changed.
   GenerateDirectLoadGlobalFunctionPrototype(masm(),
                                             Context::STRING_FUNCTION_INDEX,
-                                            rax);
+                                            rax,
+                                            &miss);
   ASSERT(object != holder);
   CheckPrototypes(JSObject::cast(object->GetPrototype()), rax, holder,
                   rbx, rdx, rdi, name, &miss);
 
   Register receiver = rbx;
   Register index = rdi;
   Register scratch = rdx;
   Register result = rax;
   __ movq(receiver, Operand(rsp, (argc + 1) * kPointerSize));
   if (argc > 0) {
@@ skipping 1362 matching lines @@
   // Return the generated code.
   return GetCode();
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64