VM: Simplify irregexp entry stub.

runtime/vm/intrinsifier_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_X64.
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/intrinsifier.h"
 
 #include "vm/assembler.h"
@@ skipping 1952 matching lines @@
   // string CIDs as well as stored function pointers are in sequence.
   __ movq(RBX, Address(RSP, kRegExpParamOffset));
   __ movq(RDI, Address(RSP, kStringParamOffset));
   __ LoadClassId(RDI, RDI);
   __ SubImmediate(RDI, Immediate(kOneByteStringCid));
   __ movq(RAX, FieldAddress(RBX, RDI, TIMES_8,
                             JSRegExp::function_offset(kOneByteStringCid)));
 
   // Registers are now set up for the lazy compile stub. It expects the function
   // in RAX, the argument descriptor in R10, and IC-Data in RCX.
-  static const intptr_t arg_count = RegExpMacroAssembler::kParamCount;
-  __ LoadObject(R10,
-      Array::ZoneHandle(ArgumentsDescriptor::New(arg_count)));
   __ xorq(RCX, RCX);
 
   // Tail-call the function.
   __ movq(RDI, FieldAddress(RAX, Function::entry_point_offset()));
   __ jmp(RDI);
 }
 
 
 // On stack: user tag (+1), return-address (+0).
 void Intrinsifier::UserTag_makeCurrent(Assembler* assembler) {
@@ skipping 24 matching lines @@
   __ LoadIsolate(RAX);
   __ movq(RAX, Address(RAX, Isolate::current_tag_offset()));
   __ ret();
 }
 
 #undef __
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64