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

src/mips/builtins-mips.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_MIPS
 
 #include "src/codegen.h"
 #include "src/debug/debug.h"
 #include "src/deoptimizer.h"
 #include "src/full-codegen/full-codegen.h"
@@ skipping 1743 matching lines @@
 
 // static
 void Builtins::Generate_ConstructProxy(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- a0 : the number of arguments (not including the receiver)
   //  -- a1 : the constructor to call (checked to be a JSProxy)
   //  -- a3 : 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(a1);
+  __ Push(a3);
+  // Include the pushed new_target, constructor and the receiver.
+  __ Addu(a0, a0, 3);
+  // Tail-call to the runtime.
+  __ JumpToExternalReference(
+      ExternalReference(Runtime::kJSProxyConstruct, masm->isolate()));
 }
 
 
 // static
 void Builtins::Generate_Construct(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- a0 : the number of arguments (not including the receiver)
   //  -- a1 : the constructor to call (can be any Object)
   //  -- a3 : 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(a1, &non_constructor);
 
   // Dispatch based on instance type.
   __ lw(t1, FieldMemOperand(a1, HeapObject::kMapOffset));
   __ lbu(t2, FieldMemOperand(t1, Map::kInstanceTypeOffset));
   __ Jump(masm->isolate()->builtins()->ConstructFunction(),
           RelocInfo::CODE_TARGET, eq, t2, Operand(JS_FUNCTION_TYPE));
-  __ Jump(masm->isolate()->builtins()->ConstructProxy(), RelocInfo::CODE_TARGET,
-          eq, t2, Operand(JS_PROXY_TYPE));
 
   // Check if target has a [[Construct]] internal method.
   __ lbu(t2, FieldMemOperand(t1, Map::kBitFieldOffset));
   __ And(t2, t2, Operand(1 << Map::kIsCallable));
   __ Branch(&non_constructor, eq, t2, Operand(zero_reg));
 
+  // Only dispatch to proxies after checking whether they are constructors.
+  __ Jump(masm->isolate()->builtins()->ConstructProxy(), RelocInfo::CODE_TARGET,
+          eq, t2, Operand(JS_PROXY_TYPE));
+
   // Called Construct on an exotic Object with a [[Construct]] internal method.
   {
     // Overwrite the original receiver with the (original) target.
     __ sll(at, a0, kPointerSizeLog2);
     __ addu(at, sp, at);
     __ sw(a1, MemOperand(at));
     // Let the "call_as_constructor_delegate" take care of the rest.
     __ LoadNativeContextSlot(Context::CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, a1);
     __ Jump(masm->isolate()->builtins()->CallFunction(),
             RelocInfo::CODE_TARGET);
@@ skipping 161 matching lines @@
   }
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS