Draft of ES5 fix to Function.prototype.call and apply

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index d738261a1b84ad3240c52d2f64cb122864f6baa5..d301f04f1976e9fcba68ce344ed2e125e3c1df95 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -610,62 +610,16 @@ void Builtins::Generate_FunctionCall(MacroAssembler* masm) {
   __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rcx);
   __ j(not_equal, &non_function);
 
-  // 3a. Patch the first argument if necessary when calling a function.
-  Label shift_arguments;
-  { Label convert_to_object, use_global_receiver, patch_receiver;
-    // Change context eagerly in case we need the global receiver.
-    __ movq(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
-
-    __ movq(rbx, Operand(rsp, rax, times_pointer_size, 0));
-    __ JumpIfSmi(rbx, &convert_to_object);
-
-    __ CompareRoot(rbx, Heap::kNullValueRootIndex);
-    __ j(equal, &use_global_receiver);
-    __ CompareRoot(rbx, Heap::kUndefinedValueRootIndex);
-    __ j(equal, &use_global_receiver);
-
-    __ CmpObjectType(rbx, FIRST_JS_OBJECT_TYPE, rcx);
-    __ j(below, &convert_to_object);
-    __ CmpInstanceType(rcx, LAST_JS_OBJECT_TYPE);
-    __ j(below_equal, &shift_arguments);
-
-    __ bind(&convert_to_object);
-    __ EnterInternalFrame();  // In order to preserve argument count.
-    __ Integer32ToSmi(rax, rax);
-    __ push(rax);
-
-    __ push(rbx);
-    __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
-    __ movq(rbx, rax);
-
-    __ pop(rax);
-    __ SmiToInteger32(rax, rax);
-    __ LeaveInternalFrame();
-    // Restore the function to rdi.
-    __ movq(rdi, Operand(rsp, rax, times_pointer_size, 1 * kPointerSize));
-    __ jmp(&patch_receiver);
-
-    // Use the global receiver object from the called function as the
-    // receiver.
-    __ bind(&use_global_receiver);
-    const int kGlobalIndex =
-        Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
-    __ movq(rbx, FieldOperand(rsi, kGlobalIndex));
-    __ movq(rbx, FieldOperand(rbx, GlobalObject::kGlobalContextOffset));
-    __ movq(rbx, FieldOperand(rbx, kGlobalIndex));
-    __ movq(rbx, FieldOperand(rbx, GlobalObject::kGlobalReceiverOffset));
-
-    __ bind(&patch_receiver);
-    __ movq(Operand(rsp, rax, times_pointer_size, 0), rbx);
-
-    __ jmp(&shift_arguments);
-  }
+  // Change context eagerly in case we need the global receiver.
+  __ movq(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
 
+  Label shift_arguments;
+  __ jmp(&shift_arguments);
 
-  // 3b. Patch the first argument when calling a non-function.  The
-  //     CALL_NON_FUNCTION builtin expects the non-function callee as
-  //     receiver, so overwrite the first argument which will ultimately
-  //     become the receiver.
+  // 3. Patch the first argument when calling a non-function.  The
+  //    CALL_NON_FUNCTION builtin expects the non-function callee as
+  //    receiver, so overwrite the first argument which will ultimately
+  //    become the receiver.
   __ bind(&non_function);
   __ movq(Operand(rsp, rax, times_pointer_size, 0), rdi);
   __ Set(rdi, 0);
@@ -769,40 +723,8 @@ void Builtins::Generate_FunctionApply(MacroAssembler* masm) {
   __ movq(rdi, Operand(rbp, kFunctionOffset));
   __ movq(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
 
-  // Compute the receiver.
-  Label call_to_object, use_global_receiver, push_receiver;
-  __ movq(rbx, Operand(rbp, kReceiverOffset));
-  __ JumpIfSmi(rbx, &call_to_object);
-  __ CompareRoot(rbx, Heap::kNullValueRootIndex);
-  __ j(equal, &use_global_receiver);
-  __ CompareRoot(rbx, Heap::kUndefinedValueRootIndex);
-  __ j(equal, &use_global_receiver);
-
-  // If given receiver is already a JavaScript object then there's no
-  // reason for converting it.
-  __ CmpObjectType(rbx, FIRST_JS_OBJECT_TYPE, rcx);
-  __ j(below, &call_to_object);
-  __ CmpInstanceType(rcx, LAST_JS_OBJECT_TYPE);
-  __ j(below_equal, &push_receiver);
-
-  // Convert the receiver to an object.
-  __ bind(&call_to_object);
-  __ push(rbx);
-  __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
-  __ movq(rbx, rax);
-  __ jmp(&push_receiver);
-
-  // Use the current global receiver object as the receiver.
-  __ bind(&use_global_receiver);
-  const int kGlobalOffset =
-      Context::kHeaderSize + Context::GLOBAL_INDEX * kPointerSize;
-  __ movq(rbx, FieldOperand(rsi, kGlobalOffset));
-  __ movq(rbx, FieldOperand(rbx, GlobalObject::kGlobalContextOffset));
-  __ movq(rbx, FieldOperand(rbx, kGlobalOffset));
-  __ movq(rbx, FieldOperand(rbx, GlobalObject::kGlobalReceiverOffset));
-
   // Push the receiver.
-  __ bind(&push_receiver);
+  __ movq(rbx, Operand(rbp, kReceiverOffset));
   __ push(rbx);
 
   // Copy all arguments from the array to the stack.