Work In Progress: support 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 4fa405d55f4ec8c9bb066844448ee37d424ede9e..7e4c9f8a6cac2625f1d6989a77350e85d298cbb6 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
@@ -163,6 +164,10 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     // Push the function to invoke on the stack.
     __ Push(rdi);
 
+    if (use_new_target) {
+      __ Push(rdx);
+    }
+
     Label rt_call, normal_new, allocated, count_incremented;
     __ cmpp(rdx, rdi);
     __ j(equal, &normal_new);
@@ -402,6 +407,10 @@ 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));
     __ SmiToInteger32(rax, rax);
@@ -410,6 +419,11 @@ 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.
@@ -425,6 +439,10 @@ 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));
@@ -437,7 +455,9 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     }
 
     // Store offset of return address for deoptimizer.
-    if (!is_api_function) {
+    // TODO(adamk): Remove the "!use_new_target" before supporting optimization
+    // of functions that reference new.target
+    if (!is_api_function && !use_new_target) {
       masm->isolate()->heap()->SetConstructStubDeoptPCOffset(masm->pc_offset());
     }
 
@@ -481,12 +501,17 @@ 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);
 }