Work In Progress: support new.target

src/x64/full-codegen-x64.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 222 matching lines @@
   // Possibly set up a local binding to the this function which is used in
   // derived constructors with super calls.
   Variable* this_function_var = scope()->this_function_var();
   if (this_function_var != nullptr) {
     Comment cmnt(masm_, "[ This function");
     SetVar(this_function_var, rdi, rbx, rdx);
   }
 
   Variable* new_target_var = scope()->new_target_var();
   if (new_target_var != nullptr) {
+    // If this is a [[Construct]] then the new.target is passed as the -2
+    // argument. If it is a [[Call]] this is always undefined.
     Comment cmnt(masm_, "[ new.target");
+    Label assign, construct, check_frame_marker;
+    __ movp(rax, Operand(rbp, StandardFrameConstants::kCallerFPOffset));
+    __ Cmp(Operand(rax, StandardFrameConstants::kContextOffset),
+           Smi::FromInt(StackFrame::ARGUMENTS_ADAPTOR));
+    __ j(not_equal, &check_frame_marker);
+    __ movp(rax, Operand(rax, StandardFrameConstants::kCallerFPOffset));
+    __ bind(&check_frame_marker);
+    __ Cmp(Operand(rax, StandardFrameConstants::kMarkerOffset),
+           Smi::FromInt(StackFrame::CONSTRUCT));
+    __ j(equal, &construct);
+
+    // [[Call]]
+    __ LoadRoot(rax, Heap::kUndefinedValueRootIndex);
+    __ jmp(&assign);
+
+    // [[Construct]]
+    __ bind(&construct);
+
     // new.target is parameter -2.
     int offset = 2 * kPointerSize + kFPOnStackSize + kPCOnStackSize +
                  (info_->scope()->num_parameters() - 1) * kPointerSize;
     __ movp(rax, Operand(rbp, offset));
+
+    __ bind(&assign);
     SetVar(new_target_var, rax, rbx, rdx);
   }
 
   ArgumentsAccessStub::HasNewTarget has_new_target =
-      IsSubclassConstructor(info->function()->kind())
+      (info->scope()->new_target_var() != nullptr ||
+       IsSubclassConstructor(info->function()->kind()))
           ? ArgumentsAccessStub::HAS_NEW_TARGET
           : ArgumentsAccessStub::NO_NEW_TARGET;
 
   // Possibly allocate RestParameters
   int rest_index;
   Variable* rest_param = scope()->rest_parameter(&rest_index);
   if (rest_param) {
     Comment cmnt(masm_, "[ Allocate rest parameter array");
 
     int num_parameters = info->scope()->num_parameters();
@@ skipping 195 matching lines @@
 #endif
     CodeGenerator::RecordPositions(masm_, function()->end_position() - 1);
     __ RecordJSReturn();
     // Do not use the leave instruction here because it is too short to
     // patch with the code required by the debugger.
     __ movp(rsp, rbp);
     __ popq(rbp);
     int no_frame_start = masm_->pc_offset();
 
     int arg_count = info_->scope()->num_parameters() + 1;
-    if (IsSubclassConstructor(info_->function()->kind())) {
+    if (info_->scope()->new_target_var() != nullptr ||
+        IsSubclassConstructor(info_->function()->kind())) {
       arg_count++;
     }
     int arguments_bytes = arg_count * kPointerSize;
     __ Ret(arguments_bytes, rcx);
 
     // Add padding that will be overwritten by a debugger breakpoint.  We
     // have just generated at least 7 bytes: "movp rsp, rbp; pop rbp; ret k"
     // (3 + 1 + 3) for x64 and at least 6 (2 + 1 + 3) bytes for x32.
     const int kPadding = Assembler::kJSReturnSequenceLength -
                          kPointerSize == kInt64Size ? 7 : 6;
@@ skipping 5002 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64