Cleanup of class id loading sequences.

runtime/vm/assembler_ia32.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"
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/cpu.h"
@@ skipping 1397 matching lines @@
   EmitOperand(reg, address);
 }
 
 
 void Assembler::cmpl(const Address& address, const Immediate& imm) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitComplex(7, address, imm);
 }
 
 
+void Assembler::cmpb(const Address& address, const Immediate& imm) {
+  ASSERT(imm.is_int8());
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0x80);
+  EmitOperand(7, address);
+  EmitUint8(imm.value() & 0xFF);
+}
+
+
 void Assembler::testl(Register reg1, Register reg2) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x85);
   EmitRegisterOperand(reg1, reg2);
 }
 
 
 void Assembler::testl(Register reg, const Immediate& immediate) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   // For registers that have a byte variant (EAX, EBX, ECX, and EDX)
@@ skipping 1277 matching lines @@
 
 
 void Assembler::CompareClassId(Register object,
                                intptr_t class_id,
                                Register scratch) {
   LoadClassId(scratch, object);
   cmpl(scratch, Immediate(class_id));
 }
 
 
-void Assembler::LoadTaggedClassIdMayBeSmi(
-    Register result, Register object, Register tmp) {
-  ASSERT(object != tmp);
-  ASSERT(result != tmp);
+void Assembler::LoadTaggedClassIdMayBeSmi(Register result, Register object) {
+  ASSERT(result != object);
   static const intptr_t kSmiCidSource = kSmiCid << RawObject::kClassIdTagPos;
 
-  if (result == object) {
-    movl(tmp, object);
-  } else {
-    tmp = object;
-  }
-
   // Make a dummy "Object" whose cid is kSmiCid.
   movl(result, Immediate(reinterpret_cast<int32_t>(&kSmiCidSource) + 1));
 
   // Check if object (in tmp) is a Smi.
-  testl(tmp, Immediate(kSmiTagMask));
+  testl(object, Immediate(kSmiTagMask));
 
   // If the object is not a Smi, use the original object to load the cid.
   // Otherwise, the dummy object is used, and the result is kSmiCid.
-  cmovne(result, tmp);
+  cmovne(result, object);
   LoadClassId(result, result);
 
   // Tag the result.
   SmiTag(result);
 }
 
 
 static const char* cpu_reg_names[kNumberOfCpuRegisters] = {
   "eax", "ecx", "edx", "ebx", "esp", "ebp", "esi", "edi"
 };
@@ skipping 12 matching lines @@
 
 const char* Assembler::FpuRegisterName(FpuRegister reg) {
   ASSERT((0 <= reg) && (reg < kNumberOfXmmRegisters));
   return xmm_reg_names[reg];
 }
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_IA32