[builtins] Sanitize the machinery around Construct calls.

src/x64/interface-descriptors-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.
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/interface-descriptors.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 168 matching lines @@
     CallInterfaceDescriptorData* data) {
   Register registers[] = {rdi, rdx, rbx};
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 
 void CallConstructDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   // rax : number of arguments
   // rbx : feedback vector
-  // rcx : new target (for IsSuperConstructorCall)
   // rdx : slot in feedback vector (Smi, for RecordCallTarget)
   // rdi : constructor function
   // TODO(turbofan): So far we don't gather type feedback and hence skip the
   // slot parameter, but ArrayConstructStub needs the vector to be undefined.
-  Register registers[] = {rax, rdi, rcx, rbx};
+  Register registers[] = {rax, rdi, rbx};
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 
 void CallTrampolineDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   // rax : number of arguments
   // rdi : the target to call
   Register registers[] = {rdi, rax};
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 
+void ConstructTrampolineDescriptor::InitializePlatformSpecific(
+    CallInterfaceDescriptorData* data) {
+  // rax : number of arguments
+  // rdx : the new target
+  // rdi : the target to call
+  Register registers[] = {rdi, rdx, rax};
+  data->InitializePlatformSpecific(arraysize(registers), registers);
+}
+
+
 void RegExpConstructResultDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {rcx, rbx, rax};
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 
 void TransitionElementsKindDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {rax, rbx};
@@ skipping 208 matching lines @@
       r15,  // address of first argument (argv)
       rbx   // the runtime function to call
   };
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64