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

src/mips/code-stubs-mips.cc

Index: src/mips/code-stubs-mips.cc
diff --git a/src/mips/code-stubs-mips.cc b/src/mips/code-stubs-mips.cc
index c3d5661919049fcffb66e7234b03ccec000fce85..f6c47b24f523b541278f8bc082f2c55c5ea031ab 100644
--- a/src/mips/code-stubs-mips.cc
+++ b/src/mips/code-stubs-mips.cc
@@ -2882,6 +2882,7 @@ void CallApiCallbackStub::Generate(MacroAssembler* masm) {
   //  -- ...
   //  -- sp[(argc - 1)* 4]   : first argument
   //  -- sp[argc * 4]        : receiver
+  //  -- sp[(argc + 1)* 4]   : accessor_holder
   // -----------------------------------
 
   Register callee = a0;
@@ -2907,10 +2908,6 @@ void CallApiCallbackStub::Generate(MacroAssembler* masm) {
 
   // Save context, callee and call data.
   __ Push(context, callee, call_data);
-  if (!is_lazy()) {
-    // Load context from callee.
-    __ lw(context, FieldMemOperand(callee, JSFunction::kContextOffset));
-  }
 
   Register scratch = call_data;
   __ LoadRoot(scratch, Heap::kUndefinedValueRootIndex);
@@ -2920,6 +2917,20 @@ void CallApiCallbackStub::Generate(MacroAssembler* masm) {
   // Push isolate and holder.
   __ Push(scratch, holder);
 
+  // Enter a new context
+  if (is_lazy()) {
+    // Load context from accessor_holder
+    Register accessor_holder = context;
+    __ lw(accessor_holder,
+          MemOperand(sp, (FCA::kArgsLength + 1 + argc()) * kPointerSize));
+    __ lw(scratch, FieldMemOperand(accessor_holder, HeapObject::kMapOffset));
+    __ GetMapConstructor(scratch, scratch, context, callee);
+    __ lw(context, FieldMemOperand(scratch, JSFunction::kContextOffset));
+  } else {
+    // Load context from callee.
+    __ lw(context, FieldMemOperand(callee, JSFunction::kContextOffset));
+  }
+
   // Prepare arguments.
   __ mov(scratch, sp);
 
@@ -2957,11 +2968,9 @@ void CallApiCallbackStub::Generate(MacroAssembler* masm) {
     return_value_offset = 2 + FCA::kReturnValueOffset;
   }
   MemOperand return_value_operand(fp, return_value_offset * kPointerSize);
-  int stack_space = 0;
-  int32_t stack_space_offset = 3 * kPointerSize;
-  stack_space = argc() + FCA::kArgsLength + 1;
+  const int stack_space = argc() + FCA::kArgsLength + 2;
   // TODO(adamk): Why are we clobbering this immediately?
-  stack_space_offset = kInvalidStackOffset;
+  const int32_t stack_space_offset = kInvalidStackOffset;
   CallApiFunctionAndReturn(masm, api_function_address, thunk_ref, stack_space,
                            stack_space_offset, return_value_operand,
                            &context_restore_operand);