WIP: new.target

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 7c670d448b9b4712d63193252d55246cb8db1496..b0b86b25cfbb63ad347d4643aa05a64630fe770a 100644
--- a/src/x64/builtins-x64.cc
+++ b/src/x64/builtins-x64.cc
@@ -136,6 +136,7 @@ static void Generate_Runtime_NewObject(MacroAssembler* masm,
 
 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                            bool is_api_function,
+                                           bool use_new_target,
                                            bool create_memento) {
   // ----------- S t a t e -------------
   //  -- rax: number of arguments
@@ -161,6 +162,10 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     __ Push(rax);
 
     // Push the function to invoke on the stack.
+
+    if (use_new_target) {
+      __ Push(rdx);
+    }
     __ Push(rdi);
 
     Label rt_call, normal_new, allocated, count_incremented;
@@ -409,6 +414,9 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
 
     // Retrieve the function from the stack.
     __ Pop(rdi);
+    if (use_new_target) {
+      __ Pop(rdx);
+    }
 
     // Retrieve smi-tagged arguments count from the stack.
     __ movp(rax, Operand(rsp, 0));
@@ -418,6 +426,9 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     // because we may have to return the original one and the calling
     // conventions dictate that the called function pops the receiver.
     __ Push(rbx);
+    if (use_new_target) {
+      __ Push(rdx);
+    }
     __ Push(rbx);
 
     // Set up pointer to last argument.
@@ -433,6 +444,10 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     __ decp(rcx);
     __ j(greater_equal, &loop);
 
+    // if (use_new_target) {
+    //   __ incp(rax);  // Pushed new.target
+    // }
+
     // Call the function.
     if (is_api_function) {
       __ movp(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
@@ -445,7 +460,7 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     }
 
     // Store offset of return address for deoptimizer.
-    if (!is_api_function) {
+    if (!is_api_function && !use_new_target) {
       masm->isolate()->heap()->SetConstructStubDeoptPCOffset(masm->pc_offset());
     }
 
@@ -468,11 +483,13 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     // Throw away the result of the constructor invocation and use the
     // on-stack receiver as the result.
     __ bind(&use_receiver);
-    __ movp(rax, Operand(rsp, 0));
+    __ movp(rax, Operand(rsp, (use_new_target ? 1 : 0) * kPointerSize));
 
     // Restore the arguments count and leave the construct frame.
     __ bind(&exit);
-    __ movp(rbx, Operand(rsp, kPointerSize));  // Get arguments count.
+    // Get arguments count.
+    int offset = (use_new_target ? 2 : 1) * kPointerSize;
+    __ movp(rbx, Operand(rsp, offset));
 
     // Leave construct frame.
   }
@@ -489,12 +506,17 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
 
 
 void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, FLAG_pretenuring_call_new);
+  Generate_JSConstructStubHelper(masm, false, false, FLAG_pretenuring_call_new);
 }
 
 
 void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, true, false);
+  Generate_JSConstructStubHelper(masm, true, false, false);
+}
+
+
+void Builtins::Generate_JSConstructStubNewTarget(MacroAssembler* masm) {
+  Generate_JSConstructStubHelper(masm, false, true, FLAG_pretenuring_call_new);
 }
 
 
@@ -535,7 +557,7 @@ void Builtins::Generate_JSConstructStubForDerived(MacroAssembler* masm) {
     __ decp(rcx);
     __ j(greater_equal, &loop);
 
-    __ incp(rax);  // Pushed new.target.
+    // __ incp(rax);  // Pushed new.target.
 
     // Handle step in.
     Label skip_step_in;
@@ -561,8 +583,11 @@ void Builtins::Generate_JSConstructStubForDerived(MacroAssembler* masm) {
     // Restore context from the frame.
     __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
 
-    __ movp(rbx, Operand(rsp, 0));  // Get arguments count.
-  }                                 // Leave construct frame.
+    // Get arguments count.
+    __ movp(rbx, Operand(rsp, 0 * kPointerSize));
+
+    // Leave construct frame.
+  }
 
   // Remove caller arguments from the stack and return.
   __ PopReturnAddressTo(rcx);
@@ -1332,6 +1357,7 @@ static void Generate_ConstructHelper(MacroAssembler* masm) {
     CallConstructStub stub(masm->isolate(), SUPER_CONSTRUCTOR_CALL);
     __ call(stub.GetCode(), RelocInfo::CONSTRUCT_CALL);
 
+    // TODO(arv): Double check this drop.
     __ Drop(1);
 
     // Leave internal frame.