[runtime] [proxy] implement [[Construct]]

src/x64/builtins-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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1789 matching lines @@
   __ movp(rcx, FieldOperand(rcx, SharedFunctionInfo::kConstructStubOffset));
   __ leap(rcx, FieldOperand(rcx, Code::kHeaderSize));
   __ jmp(rcx);
 }
 
 
 // static
 void Builtins::Generate_ConstructProxy(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax : the number of arguments (not including the receiver)
+  //  -- rdi : the constructor to call (checked to be a JSProxy)
   //  -- rdx : the new target (either the same as the constructor or
   //           the JSFunction on which new was invoked initially)
-  //  -- rdi : the constructor to call (checked to be a JSProxy)
   // -----------------------------------
 
-  // TODO(neis): This doesn't match the ES6 spec for [[Construct]] on proxies.
-  __ Jump(masm->isolate()->builtins()->Call(), RelocInfo::CODE_TARGET);
+  // Call into the Runtime for Proxy [[Construct]].
+  __ PopReturnAddressTo(kScratchRegister);
+  __ Push(rdi);
+  __ Push(rdx);
+  __ PushReturnAddressFrom(kScratchRegister);
+  // Include the pushed new_target, constructor and the receiver.
+  __ addp(rax, Immediate(3));
+  __ JumpToExternalReference(
+      ExternalReference(Runtime::kJSProxyConstruct, masm->isolate()), 1);
 }
 
 
 // static
 void Builtins::Generate_Construct(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax : the number of arguments (not including the receiver)
   //  -- rdx : the new target (either the same as the constructor or
   //           the JSFunction on which new was invoked initially)
   //  -- rdi : the constructor to call (can be any Object)
   // -----------------------------------
   StackArgumentsAccessor args(rsp, rax);
 
   // Check if target is a Smi.
   Label non_constructor;
   __ JumpIfSmi(rdi, &non_constructor, Label::kNear);
 
   // Dispatch based on instance type.
   __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rcx);
   __ j(equal, masm->isolate()->builtins()->ConstructFunction(),
        RelocInfo::CODE_TARGET);
-  __ CmpInstanceType(rcx, JS_PROXY_TYPE);
-  __ j(equal, masm->isolate()->builtins()->ConstructProxy(),
-       RelocInfo::CODE_TARGET);
 
   // Check if target has a [[Construct]] internal method.
   __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
            Immediate(1 << Map::kIsConstructor));
   __ j(zero, &non_constructor, Label::kNear);
 
+  // Only dispatch to proxies after checking whether they are constructors.
+  __ CmpInstanceType(rcx, JS_PROXY_TYPE);
+  __ j(equal, masm->isolate()->builtins()->ConstructProxy(),
+       RelocInfo::CODE_TARGET);
+
   // Called Construct on an exotic Object with a [[Construct]] internal method.
   {
     // Overwrite the original receiver with the (original) target.
     __ movp(args.GetReceiverOperand(), rdi);
     // Let the "call_as_constructor_delegate" take care of the rest.
     __ LoadNativeContextSlot(Context::CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, rdi);
     __ Jump(masm->isolate()->builtins()->CallFunction(),
             RelocInfo::CODE_TARGET);
   }
 
@@ skipping 185 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64