[es6] generate rest parameters correctly for subclass constructors

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 214 matching lines @@
         } else if (FLAG_debug_code) {
           Label done;
           __ JumpIfInNewSpace(rsi, rax, &done, Label::kNear);
           __ Abort(kExpectedNewSpaceObject);
           __ bind(&done);
         }
       }
     }
   }
 
+ArgumentsAccessStub::HasNewTarget has_new_target =
+    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();
     int offset = num_parameters * kPointerSize;
+    if (has_new_target == ArgumentsAccessStub::HAS_NEW_TARGET) {
+      --num_parameters;
+      ++rest_index;
+    }
+
     __ leap(rdx,
             Operand(rbp, StandardFrameConstants::kCallerSPOffset + offset));
     __ Push(rdx);
     __ Push(Smi::FromInt(num_parameters));
     __ Push(Smi::FromInt(rest_index));
 
     RestParamAccessStub stub(isolate());
     __ CallStub(&stub);
 
     SetVar(rest_param, rax, rbx, rdx);
@@ skipping 15 matching lines @@
     int offset = num_parameters * kPointerSize;
     __ leap(rdx,
            Operand(rbp, StandardFrameConstants::kCallerSPOffset + offset));
     __ Push(rdx);
     __ Push(Smi::FromInt(num_parameters));
     // Arguments to ArgumentsAccessStub:
     //   function, receiver address, parameter count.
     // The stub will rewrite receiver and parameter count if the previous
     // stack frame was an arguments adapter frame.
 
-    ArgumentsAccessStub::HasNewTarget has_new_target =
-        IsSubclassConstructor(info->function()->kind())
-            ? ArgumentsAccessStub::HAS_NEW_TARGET
-            : ArgumentsAccessStub::NO_NEW_TARGET;
     ArgumentsAccessStub::Type type;
     if (is_strict(language_mode()) || !is_simple_parameter_list()) {
       type = ArgumentsAccessStub::NEW_STRICT;
     } else if (function()->has_duplicate_parameters()) {
       type = ArgumentsAccessStub::NEW_SLOPPY_SLOW;
     } else {
       type = ArgumentsAccessStub::NEW_SLOPPY_FAST;
     }
     ArgumentsAccessStub stub(isolate(), type, has_new_target);
     __ CallStub(&stub);
@@ skipping 5108 matching lines @@
   DCHECK_EQ(isolate->builtins()->OsrAfterStackCheck()->entry(),
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64