Revert of [es6] Introduce spec compliant IsConstructor.

src/x64/builtins-x64.cc

Index: src/x64/builtins-x64.cc
diff --git a/src/x64/builtins-x64.cc b/src/x64/builtins-x64.cc
index a7e8c98881e2985c87ab58d1385f6970ee484065..41c224f8dd24a93f3879a1bc08fe187114720bee 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -1781,21 +1781,6 @@
 
 
 // static
-void Builtins::Generate_ConstructProxy(MacroAssembler* masm) {
-  // ----------- S t a t e -------------
-  //  -- rax : the number of arguments (not including the receiver)
-  //  -- rdx : the original constructor (either the same as the constructor or
-  //           the JSFunction on which new was invoked initially)
-  //  -- rdi : the constructor to call (checked to be a JSFunctionProxy)
-  // -----------------------------------
-
-  // TODO(neis): This doesn't match the ES6 spec for [[Construct]] on proxies.
-  __ movp(rdi, FieldOperand(rdi, JSFunctionProxy::kConstructTrapOffset));
-  __ Jump(masm->isolate()->builtins()->Call(), RelocInfo::CODE_TARGET);
-}
-
-
-// static
 void Builtins::Generate_Construct(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax : the number of arguments (not including the receiver)
@@ -1805,35 +1790,35 @@
   // -----------------------------------
   StackArgumentsAccessor args(rsp, rax);
 
-  // Check if target has a [[Construct]] internal method.
-  Label non_constructor;
-  __ JumpIfSmi(rdi, &non_constructor, Label::kNear);
-  __ movp(rcx, FieldOperand(rdi, HeapObject::kMapOffset));
-  __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
-           Immediate(1 << Map::kIsConstructor));
-  __ j(zero, &non_constructor, Label::kNear);
-
-  // Dispatch based on instance type.
-  __ CmpInstanceType(rcx, JS_FUNCTION_TYPE);
+  Label non_callable, non_function;
+  __ JumpIfSmi(rdi, &non_callable);
+  __ CmpObjectType(rdi, JS_FUNCTION_TYPE, rcx);
   __ j(equal, masm->isolate()->builtins()->ConstructFunction(),
        RelocInfo::CODE_TARGET);
   __ CmpInstanceType(rcx, JS_FUNCTION_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.
-    __ LoadGlobalFunction(Context::CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, rdi);
-    __ Jump(masm->isolate()->builtins()->CallFunction(),
-            RelocInfo::CODE_TARGET);
-  }
-
-  // Called Construct on an Object that doesn't have a [[Construct]] internal
-  // method.
-  __ bind(&non_constructor);
+  __ j(not_equal, &non_function, Label::kNear);
+
+  // 1. Construct of function proxy.
+  // TODO(neis): This doesn't match the ES6 spec for [[Construct]] on proxies.
+  __ movp(rdi, FieldOperand(rdi, JSFunctionProxy::kConstructTrapOffset));
+  __ Jump(masm->isolate()->builtins()->Call(), RelocInfo::CODE_TARGET);
+
+  // 2. Construct of something else, which might have a [[Construct]] internal
+  // method (if not we raise an exception).
+  __ bind(&non_function);
+  // Check if target has a [[Call]] internal method.
+  // TODO(bmeurer): This shoud use IsConstructor once available.
+  __ testb(FieldOperand(rcx, Map::kBitFieldOffset),
+           Immediate(1 << Map::kIsCallable));
+  __ j(zero, &non_callable, Label::kNear);
+  // Overwrite the original receiver with the (original) target.
+  __ movp(args.GetReceiverOperand(), rdi);
+  // Let the "call_as_constructor_delegate" take care of the rest.
+  __ LoadGlobalFunction(Context::CALL_AS_CONSTRUCTOR_DELEGATE_INDEX, rdi);
+  __ Jump(masm->isolate()->builtins()->CallFunction(), RelocInfo::CODE_TARGET);
+
+  // 3. Construct of something that is not callable.
+  __ bind(&non_callable);
   {
     FrameScope scope(masm, StackFrame::INTERNAL);
     __ Push(rdi);