In generated code for x64 don't load object's class directly from class_ field.

runtime/vm/intrinsifier_ia32.cc

Index: runtime/vm/intrinsifier_ia32.cc
diff --git a/runtime/vm/intrinsifier_ia32.cc b/runtime/vm/intrinsifier_ia32.cc
index 11e2c40c712a4953aa7ef23b25c7a35de07971d2..1a3c1516c0d5725fcaae4317f4053d2803a4d34a 100644
--- a/runtime/vm/intrinsifier_ia32.cc
+++ b/runtime/vm/intrinsifier_ia32.cc
@@ -204,9 +204,7 @@ bool Intrinsifier::Array_setIndexed(Assembler* assembler) {
     __ j(EQUAL, &checked_ok, Assembler::kNearJump);
     // Check if it's Dynamic.
     // For now handle only TypeArguments and bail out if InstantiatedTypeArgs.
-    __ CompareClassOfObject(EBX,
-                            Class::Handle(Object::type_arguments_class()),
-                            EAX);
+    __ CompareClassId(EBX, kTypeArguments, EAX);
     __ j(NOT_EQUAL, &fall_through, Assembler::kNearJump);
     // Get type at index 0.
     __ movl(EAX, FieldAddress(EBX, TypeArguments::type_at_offset(0)));
@@ -740,7 +738,6 @@ bool Intrinsifier::Integer_equalToInteger(Assembler* assembler) {
 
   // At least one of the arguments was not Smi, inline code for Smi/Mint
   // equality comparison.
-  ObjectStore* object_store = Isolate::Current()->object_store();
   Label receiver_not_smi;
   __ Bind(&check_for_mint);
   __ movl(EAX, Address(ESP, + 2 * kWordSize));  // Receiver.
@@ -751,14 +748,14 @@ bool Intrinsifier::Integer_equalToInteger(Assembler* assembler) {
   // represented by Smi.
   // Left is Smi, return false if right is Mint, otherwise fall through.
   __ movl(EAX, Address(ESP, + 1 * kWordSize));  // Right argument.
-  __ CompareClassOfObject(EAX, Class::Handle(object_store->mint_class()), EAX);
+  __ CompareClassId(EAX, kMint, EAX);
   __ j(NOT_EQUAL, &fall_through);
   __ LoadObject(EAX, bool_false);  // Smi == Mint -> false.
   __ ret();
 
   __ Bind(&receiver_not_smi);
   // EAX:: receiver.
-  __ CompareClassOfObject(EAX, Class::Handle(object_store->mint_class()), EAX);
+  __ CompareClassId(EAX, kMint, EAX);
   __ j(NOT_EQUAL, &fall_through);
   // Receiver is Mint, return false if right is Smi.
   __ movl(EAX, Address(ESP, + 1 * kWordSize));  // Right argument.
@@ -827,8 +824,7 @@ static void TestLastArgumentIsDouble(Assembler* assembler,
   __ movl(EAX, Address(ESP, + 1 * kWordSize));
   __ testl(EAX, Immediate(kSmiTagMask));
   __ j(ZERO, is_smi, Assembler::kNearJump);  // Jump if Smi.
-  __ CompareClassOfObject(EAX, Class::Handle(
-      Isolate::Current()->object_store()->double_class()), EBX);
+  __ CompareClassId(EAX, kDouble, EBX);
   __ j(NOT_EQUAL, not_double_smi, Assembler::kNearJump);
   // Fall through if double.
 }
@@ -1241,7 +1237,6 @@ bool Intrinsifier::String_getLength(Assembler* assembler) {
 
 // TODO(srdjan): Implement for two and four byte strings as well.
 bool Intrinsifier::String_charCodeAt(Assembler* assembler) {
-  ObjectStore* object_store = Isolate::Current()->object_store();
   Label fall_through;
   __ movl(EBX, Address(ESP, + 1 * kWordSize));  // Index.
   __ movl(EAX, Address(ESP, + 2 * kWordSize));  // String.
@@ -1251,9 +1246,7 @@ bool Intrinsifier::String_charCodeAt(Assembler* assembler) {
   __ cmpl(EBX, FieldAddress(EAX, String::length_offset()));
   // Runtime throws exception.
   __ j(ABOVE_EQUAL, &fall_through, Assembler::kNearJump);
-  __ CompareClassOfObject(EAX,
-                          Class::Handle(object_store->one_byte_string_class()),
-                          EDI);
+  __ CompareClassId(EAX, kOneByteString, EDI);
   __ j(NOT_EQUAL, &fall_through);
   __ SmiUntag(EBX);
   __ movzxb(EAX, FieldAddress(EAX, EBX, TIMES_1, OneByteString::data_offset()));