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

src/arm64/builtins-arm64.cc

 // Copyright 2013 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_ARM64
 
 #include "src/arm64/frames-arm64.h"
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
@@ skipping 1723 matching lines @@
 
 // static
 void Builtins::Generate_ConstructProxy(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- x0 : the number of arguments (not including the receiver)
   //  -- x1 : the constructor to call (checked to be a JSProxy)
   //  -- x3 : the new target (either the same as the constructor or
   //          the JSFunction on which new was invoked initially)
   // -----------------------------------
 
-  // 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]].
+  __ Push(x1);
+  __ Push(x3);
+  // Include the pushed new_target + constructor and the receiver on the stack.
+  __ Add(x0, x0, 3);
+  // Tail-call to the runtime.
+  __ JumpToExternalReference(
+      ExternalReference(Runtime::kJSProxyConstruct, masm->isolate()));
 }
 
 
 // static
 void Builtins::Generate_Construct(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- x0 : the number of arguments (not including the receiver)
   //  -- x1 : the constructor to call (can be any Object)
   //  -- x3 : the new target (either the same as the constructor or
   //          the JSFunction on which new was invoked initially)
   // -----------------------------------
 
   // Check if target is a Smi.
   Label non_constructor;
   __ JumpIfSmi(x1, &non_constructor);
 
   // Dispatch based on instance type.
   __ CompareObjectType(x1, x4, x5, JS_FUNCTION_TYPE);
   __ Jump(masm->isolate()->builtins()->ConstructFunction(),
           RelocInfo::CODE_TARGET, eq);
-  __ Cmp(x5, JS_PROXY_TYPE);
-  __ Jump(masm->isolate()->builtins()->ConstructProxy(), RelocInfo::CODE_TARGET,
-          eq);
 
   // Check if target has a [[Construct]] internal method.
   __ Ldrb(x2, FieldMemOperand(x4, Map::kBitFieldOffset));
   __ TestAndBranchIfAllClear(x2, 1 << Map::kIsConstructor, &non_constructor);
 
+  // Only dispatch to proxies after checking whether they are constructors.
+  __ Cmp(x5, JS_PROXY_TYPE);
+  __ Jump(masm->isolate()->builtins()->ConstructProxy(), RelocInfo::CODE_TARGET,
+          eq);
+
   // Called Construct on an exotic Object with a [[Construct]] internal method.
   {
     // Overwrite the original receiver with the (original) target.
     __ Poke(x1, Operand(x0, LSL, kXRegSizeLog2));
     // Let the "call_as_constructor_delegate" take care of the rest.
     __ LoadNativeContextSlot(Context::CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, x1);
     __ Jump(masm->isolate()->builtins()->CallFunction(),
             RelocInfo::CODE_TARGET);
   }
 
@@ skipping 244 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_ARM