Background compilation work:

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 2552 matching lines @@
 };
 
 
 // XMM0 is used only as a scratch register in the optimized code. No need to
 // save it.
 static const intptr_t kNumberOfVolatileXmmRegisters =
     kNumberOfXmmRegisters - 1;
 
 
 void Assembler::EnterCallRuntimeFrame(intptr_t frame_space) {
+  Comment("EnterCallRuntimeFrame");
   EnterFrame(0);
 
   // Preserve volatile CPU registers.
   for (intptr_t i = 0; i < kNumberOfVolatileCpuRegisters; i++) {
     pushl(volatile_cpu_registers[i]);
   }
 
   // Preserve all XMM registers except XMM0
   subl(ESP, Immediate((kNumberOfXmmRegisters - 1) * kFpuRegisterSize));
   // Store XMM registers with the lowest register number at the lowest
@@ skipping 628 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