[es6] Make new.target work in functions

src/x64/builtins-x64.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.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/code-factory.h"
 #include "src/codegen.h"
@@ skipping 118 matching lines @@
   if (create_memento) {
     __ jmp(count_incremented);
   } else {
     __ jmp(allocated);
   }
 }
 
 
 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
   //  -- rdi: constructor function
   //  -- rbx: allocation site or undefined
   //  -- rdx: original constructor
   // -----------------------------------
 
   // Should never create mementos for api functions.
   DCHECK(!is_api_function || !create_memento);
 
   // Enter a construct frame.
   {
     FrameScope scope(masm, StackFrame::CONSTRUCT);
 
     if (create_memento) {
       __ AssertUndefinedOrAllocationSite(rbx);
       __ Push(rbx);
     }
 
-    // Store a smi-tagged arguments count on the stack.
+    // Preserve the incoming parameters on the stack.
     __ Integer32ToSmi(rax, rax);
     __ Push(rax);
-
-    // 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);
 
     Generate_Runtime_NewObject(masm, create_memento, rdx, &count_incremented,
                                &allocated);
 
     __ bind(&normal_new);
     // Try to allocate the object without transitioning into C code. If any of
@@ skipping 206 matching lines @@
     // rdi: function (constructor)
     __ bind(&rt_call);
     Generate_Runtime_NewObject(masm, create_memento, rdi, &count_incremented,
                                &allocated);
 
     // New object allocated.
     // rbx: newly allocated object
     __ bind(&allocated);
 
     if (create_memento) {
-      __ movp(rcx, Operand(rsp, kPointerSize*2));
+      int offset = (use_new_target ? 3 : 2) * kPointerSize;
+      __ movp(rcx, Operand(rsp, offset));
       __ Cmp(rcx, masm->isolate()->factory()->undefined_value());
       __ j(equal, &count_incremented);
       // rcx is an AllocationSite. We are creating a memento from it, so we
       // need to increment the memento create count.
       __ SmiAddConstant(
           FieldOperand(rcx, AllocationSite::kPretenureCreateCountOffset),
           Smi::FromInt(1));
       __ bind(&count_incremented);
     }
 
-    // Retrieve the function from the stack.
+    // Restore the parameters.
+    if (use_new_target) {
+      __ Pop(rdx);
+    }
     __ Pop(rdi);
 
     // Retrieve smi-tagged arguments count from the stack.
     __ movp(rax, Operand(rsp, 0));
     __ SmiToInteger32(rax, rax);
 
+    // Push new.target onto the construct frame. This is stored just below the
+    // receiver on the stack.
+    if (use_new_target) {
+      __ Push(rdx);
+    }
+
     // Push the allocated receiver to the stack. We need two copies
     // because we may have to return the original one and the calling
     // conventions dictate that the called function pops the receiver.
     __ Push(rbx);
     __ Push(rbx);
 
     // Set up pointer to last argument.
     __ leap(rbx, Operand(rbp, StandardFrameConstants::kCallerSPOffset));
 
     // Copy arguments and receiver to the expression stack.
@@ skipping 11 matching lines @@
       __ movp(rsi, FieldOperand(rdi, JSFunction::kContextOffset));
       Handle<Code> code =
           masm->isolate()->builtins()->HandleApiCallConstruct();
       __ Call(code, RelocInfo::CODE_TARGET);
     } else {
       ParameterCount actual(rax);
       __ InvokeFunction(rdi, actual, CALL_FUNCTION, NullCallWrapper());
     }
 
     // Store offset of return address for deoptimizer.
-    if (!is_api_function) {
+    // TODO(arv): 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());
     }
 
     // Restore context from the frame.
     __ movp(rsi, Operand(rbp, StandardFrameConstants::kContextOffset));
 
     // If the result is an object (in the ECMA sense), we should get rid
     // of the receiver and use the result; see ECMA-262 section 13.2.2-7
     // on page 74.
     Label use_receiver, exit;
     // If the result is a smi, it is *not* an object in the ECMA sense.
     __ JumpIfSmi(rax, &use_receiver);
 
     // If the type of the result (stored in its map) is less than
     // FIRST_SPEC_OBJECT_TYPE, it is not an object in the ECMA sense.
     STATIC_ASSERT(LAST_SPEC_OBJECT_TYPE == LAST_TYPE);
     __ CmpObjectType(rax, FIRST_SPEC_OBJECT_TYPE, rcx);
     __ j(above_equal, &exit);
 
     // 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));
 
-    // Restore the arguments count and leave the construct frame.
+    // Restore the arguments count and leave the construct frame. The arguments
+    // count is stored below the reciever and the new.target.
     __ bind(&exit);
-    __ movp(rbx, Operand(rsp, kPointerSize));  // Get arguments count.
+    int offset = (use_new_target ? 2 : 1) * kPointerSize;
+    __ movp(rbx, Operand(rsp, offset));
 
     // Leave construct frame.
   }
 
   // Remove caller arguments from the stack and return.
   __ PopReturnAddressTo(rcx);
   SmiIndex index = masm->SmiToIndex(rbx, rbx, kPointerSizeLog2);
   __ leap(rsp, Operand(rsp, index.reg, index.scale, 1 * kPointerSize));
   __ PushReturnAddressFrom(rcx);
   Counters* counters = masm->isolate()->counters();
   __ IncrementCounter(counters->constructed_objects(), 1);
   __ ret(0);
 }
 
 
 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);
+}
+
+
 void Builtins::Generate_JSConstructStubForDerived(MacroAssembler* masm) {
   // ----------- S t a t e -------------
   //  -- rax: number of arguments
   //  -- rdi: constructor function
   //  -- rbx: allocation site or undefined
   //  -- rdx: original constructor
   // -----------------------------------
   // TODO(dslomov): support pretenuring
   CHECK(!FLAG_pretenuring_call_new);
 
@@ skipping 1280 matching lines @@
   __ ret(0);
 }
 
 
 #undef __
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64