[regexp] Port RegExpExecStub to CSA (mostly)

src/ppc/interface-descriptors-ppc.cc

 // Copyright 2014 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_PPC
 
 #include "src/interface-descriptors.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 34 matching lines @@
 const Register StoreTransitionDescriptor::MapRegister() { return r8; }
 
 const Register StringCompareDescriptor::LeftRegister() { return r4; }
 const Register StringCompareDescriptor::RightRegister() { return r3; }
 
 const Register ApiGetterDescriptor::HolderRegister() { return r3; }
 const Register ApiGetterDescriptor::CallbackRegister() { return r6; }
 
 const Register MathPowTaggedDescriptor::exponent() { return r5; }
 
-
 const Register MathPowIntegerDescriptor::exponent() {
   return MathPowTaggedDescriptor::exponent();
 }
 
+const Register RegExpExecDescriptor::StringRegister() { return r3; }
+const Register RegExpExecDescriptor::LastIndexRegister() { return r4; }
+const Register RegExpExecDescriptor::StringStartRegister() { return r5; }
+const Register RegExpExecDescriptor::StringEndRegister() { return r6; }
+const Register RegExpExecDescriptor::CodeRegister() { return r17; }
 
 const Register GrowArrayElementsDescriptor::ObjectRegister() { return r3; }
 const Register GrowArrayElementsDescriptor::KeyRegister() { return r6; }
 
 void FastNewClosureDescriptor::InitializePlatformSpecific(
     CallInterfaceDescriptorData* data) {
   Register registers[] = {r4, r5, r6};
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
@@ skipping 327 matching lines @@
   Register registers[] = {
       r4,  // loaded new FP
   };
   data->InitializePlatformSpecific(arraysize(registers), registers);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_PPC