Set the current context to the function's context when entering to LAP.

src/x64/code-stubs-x64.cc

Index: src/x64/code-stubs-x64.cc
diff --git a/src/x64/code-stubs-x64.cc b/src/x64/code-stubs-x64.cc
index 30fe1e44eb793f061e1b670345eeda27a8a16da5..ea069e276e1888e50861ee2406d09f72feed9eae 100644
--- a/src/x64/code-stubs-x64.cc
+++ b/src/x64/code-stubs-x64.cc
@@ -2650,6 +2650,7 @@ void CallApiCallbackStub::Generate(MacroAssembler* masm) {
   //  -- ...
   //  -- rsp[argc * 8]       : first argument
   //  -- rsp[(argc + 1) * 8] : receiver
+  //  -- rsp[(argc + 2) * 8] : accessor_holder
   // -----------------------------------
 
   Register callee = rdi;
@@ -2696,15 +2697,25 @@ void CallApiCallbackStub::Generate(MacroAssembler* masm) {
   // holder
   __ Push(holder);
 
-  __ movp(scratch, rsp);
-  // Push return address back on stack.
-  __ PushReturnAddressFrom(return_address);
-
-  if (!this->is_lazy()) {
+  // enter a new context
+  int argc = this->argc();
+  if (this->is_lazy()) {
+    // load context from accessor_holder
+    Register accessor_holder = context;
+    __ movp(accessor_holder,
+            MemOperand(rsp, (argc + FCA::kArgsLength + 1) * kPointerSize));
+    __ movp(scratch, FieldOperand(accessor_holder, HeapObject::kMapOffset));
+    __ GetMapConstructor(scratch, scratch, context);
+    __ movp(context, FieldOperand(scratch, JSFunction::kContextOffset));
+  } else {
     // load context from callee
     __ movp(context, FieldOperand(callee, JSFunction::kContextOffset));
   }
 
+  __ movp(scratch, rsp);
+  // Push return address back on stack.
+  __ PushReturnAddressFrom(return_address);
+
   // Allocate the v8::Arguments structure in the arguments' space since
   // it's not controlled by GC.
   const int kApiStackSpace = 3;
@@ -2712,7 +2723,6 @@ void CallApiCallbackStub::Generate(MacroAssembler* masm) {
   PrepareCallApiFunction(masm, kApiStackSpace);
 
   // FunctionCallbackInfo::implicit_args_.
-  int argc = this->argc();
   __ movp(StackSpaceOperand(0), scratch);
   __ addp(scratch, Immediate((argc + FCA::kArgsLength - 1) * kPointerSize));
   // FunctionCallbackInfo::values_.
@@ -2743,13 +2753,10 @@ void CallApiCallbackStub::Generate(MacroAssembler* masm) {
                                        ARGUMENTS_DONT_CONTAIN_RECEIVER);
   Operand context_restore_operand = args_from_rbp.GetArgumentOperand(
       FCA::kArgsLength - FCA::kContextSaveIndex);
-  Operand length_operand = StackSpaceOperand(2);
   Operand return_value_operand = args_from_rbp.GetArgumentOperand(
       this->is_store() ? 0 : FCA::kArgsLength - FCA::kReturnValueOffset);
-  int stack_space = 0;
-  Operand* stack_space_operand = &length_operand;
-  stack_space = argc + FCA::kArgsLength + 1;
-  stack_space_operand = nullptr;
+  const int stack_space = argc + FCA::kArgsLength + 2;
+  Operand* stack_space_operand = nullptr;
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref, callback_arg,
                            stack_space, stack_space_operand,
                            return_value_operand, &context_restore_operand);