Use kIllegalObjectKind instead of NULL object to terminate ICData array

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2012, 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"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/assembler_macros.h"
 #include "vm/compiler.h"
@@ skipping 1571 matching lines @@
       Immediate(reinterpret_cast<intptr_t>(Object::null()));
   Label loop, found;
   if (num_args == 1) {
     __ call(&get_class_id_as_smi);
     // RAX: receiver's class id as Smi.
     __ Bind(&loop);
     __ movq(R13, Address(R12, 0));  // Get class if (Smi) to check.
     __ cmpq(RAX, R13);  // Match?
     __ j(EQUAL, &found, Assembler::kNearJump);
     __ addq(R12, Immediate(kWordSize * 2));  // Next element (class + target).
-    __ cmpq(R13, raw_null);   // Done?
+    __ cmpq(R13, Immediate(Smi::RawValue(kIllegalObjectKind)));  // Done?
     __ j(NOT_EQUAL, &loop, Assembler::kNearJump);
   } else if (num_args == 2) {
     Label no_match;
     __ Bind(&loop);
     // Get receiver.
     __ movq(RAX, FieldAddress(R10, Array::data_offset()));
     __ movq(RAX, Address(RSP, RAX, TIMES_4, 0));  // RAX is Smi.
     __ call(&get_class_id_as_smi);
     __ movq(R13, Address(R12, 0));  // Get class id from IC data to check.
     __ cmpq(RAX, R13);  // Class id match?
     __ j(NOT_EQUAL, &no_match, Assembler::kNearJump);
     // Check second.
     // Get next argument.
     __ movq(RAX, FieldAddress(R10, Array::data_offset()));
     __ movq(RAX, Address(RSP, RAX, TIMES_4, -kWordSize));  // RAX is Smi.
     __ call(&get_class_id_as_smi);
     __ movq(R13, Address(R12, kWordSize));  // Get class id from IC data.
     __ cmpq(RAX, R13);  //  Class id match?
     __ j(EQUAL, &found);
     __ Bind(&no_match);
     __ addq(R12, Immediate(kWordSize * (1 + num_args)));  // Next element.
-    __ cmpq(R13, raw_null);   // Done?
+    __ cmpq(R13, Immediate(Smi::RawValue(kIllegalObjectKind)));  // Done?
     __ j(NOT_EQUAL, &loop, Assembler::kNearJump);
   }
 
   __ Bind(&ic_miss);
   // Compute address of arguments (first read number of arguments from argument
   // descriptor array and then compute address on the stack).
   __ movq(RAX, FieldAddress(R10, Array::data_offset()));
   __ leaq(RAX, Address(RSP, RAX, TIMES_4, 0));  // RAX is Smi.
   AssemblerMacros::EnterStubFrame(assembler);
   __ pushq(R10);  // Preserve arguments array.
@@ skipping 278 matching lines @@
 void StubCode::GenerateJumpToErrorHandlerStub(Assembler* assembler) {
   __ movq(RAX, RCX);  // error object.
   __ movq(RBP, RDX);  // target frame_pointer.
   __ movq(RSP, RSI);  // target stack_pointer.
   __ jmp(RDI);  // Jump to the exception handler code.
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64