Use kIllegalObjectKind instead of NULL object to terminate ICData array

runtime/vm/stub_code_ia32.cc

 // Copyright (c) 2011, 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_IA32)
 
 #include "vm/assembler.h"
 #include "vm/assembler_macros.h"
 #include "vm/compiler.h"
@@ skipping 1595 matching lines @@
   // EBX: points directly to the first ic data array element.
   Label loop, found;
   if (num_args == 1) {
     __ call(&get_class_id_as_smi);
     // EAX: receiver's class id Smi.
     __ Bind(&loop);
     __ movl(EDI, Address(EBX, 0));  // Get class id (Smi) to check.
     __ cmpl(EAX, EDI);  // Class id match?
     __ j(EQUAL, &found, Assembler::kNearJump);
     __ addl(EBX, Immediate(kWordSize * 2));  // Next element (class + target).
-    __ cmpl(EDI, raw_null);   // Done?
+    __ cmpl(EDI, Immediate(Smi::RawValue(kIllegalObjectKind)));  // Done?
     __ j(NOT_EQUAL, &loop, Assembler::kNearJump);
   } else if (num_args == 2) {
     // EDI: class to check.
     Label no_match;
     __ Bind(&loop);
     // Get class id from IC data to check.
     // Get receiver using argument descriptor in EDX.
     __ movl(EAX, FieldAddress(EDX, Array::data_offset()));
     __ movl(EAX, Address(ESP, EAX, TIMES_2, 0));  // EAX (arg. count) is Smi.
     __ call(&get_class_id_as_smi);
     __ movl(EDI, Address(EBX, 0));
     __ cmpl(EAX, EDI);  // Class id match?
     __ j(NOT_EQUAL, &no_match, Assembler::kNearJump);
     // Check second class/argument.
     // Get class id from IC data to check.
     // Get next argument.
     __ movl(EAX, FieldAddress(EDX, Array::data_offset()));
     __ movl(EAX, Address(ESP, EAX, TIMES_2, -kWordSize));
     // EAX (argument count) is Smi.
     __ call(&get_class_id_as_smi);
     __ movl(EDI, Address(EBX, kWordSize));
     __ cmpl(EAX, EDI);  // Class id match?
     __ j(EQUAL, &found, Assembler::kNearJump);
     __ Bind(&no_match);
     // Each test entry has (1 + num_args) array elements.
     __ addl(EBX, Immediate(kWordSize * (1 + num_args)));  // Next element.
-    __ cmpl(EDI, raw_null);   // Done?
+    __ cmpl(EDI, 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).
   __ movl(EAX, FieldAddress(EDX, Array::data_offset()));
   __ leal(EAX, Address(ESP, EAX, TIMES_2, 0));  // EAX is Smi.
   // Create a stub frame as we are pushing some objects on the stack before
   // calling into the runtime.
@@ skipping 291 matching lines @@
   __ movl(EAX, Address(ESP, 4 * kWordSize));  // Load error object.
   __ movl(EBP, Address(ESP, 3 * kWordSize));  // Load target frame_pointer.
   __ movl(EBX, Address(ESP, 1 * kWordSize));  // Load target PC into EBX.
   __ movl(ESP, Address(ESP, 2 * kWordSize));  // Load target stack_pointer.
   __ jmp(EBX);  // Jump to the exception handler code.
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32