VM: More compact code for pushing constant arguments on ia32/x64.

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"  // NOLINT
 #if defined(TARGET_ARCH_IA32)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/cpu.h"
@@ skipping 78 matching lines @@
 
 void Assembler::pushl(const Address& address) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0xFF);
   EmitOperand(6, address);
 }
 
 
 void Assembler::pushl(const Immediate& imm) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
-  EmitUint8(0x68);
-  EmitImmediate(imm);
+  if (imm.is_int8()) {
+    EmitUint8(0x6A);
+    EmitUint8(imm.value() & 0xFF);
+  } else {
+    EmitUint8(0x68);
+    EmitImmediate(imm);
+  }
 }
 
 
 void Assembler::popl(Register reg) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x58 + reg);
 }
 
 
 void Assembler::popl(const Address& address) {
@@ skipping 3095 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