Improve generated MIPS code for conditional expressions and branches by delaying

runtime/vm/assembler_mips.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_MIPS)
 
 #include "vm/assembler.h"
 #include "vm/longjump.h"
 #include "vm/runtime_entry.h"
 #include "vm/simulator.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 
 namespace dart {
 
 #if defined(USING_SIMULATOR)
-DECLARE_FLAG(bool, trace_sim);
+DECLARE_FLAG(int, trace_sim_after);
 #endif
 DEFINE_FLAG(bool, print_stop_message, false, "Print stop message.");
 DECLARE_FLAG(bool, inline_alloc);
 
 void Assembler::InitializeMemoryWithBreakpoints(uword data, intptr_t length) {
   ASSERT(Utils::IsAligned(data, 4));
   ASSERT(Utils::IsAligned(length, 4));
   const uword end = data + length;
   while (data < end) {
     *reinterpret_cast<int32_t*>(data) = Instr::kBreakPointInstruction;
@@ skipping 467 matching lines @@
 }
 
 
 void Assembler::PushObject(const Object& object) {
   ASSERT(!in_delay_slot_);
   LoadObject(TMP, object);
   Push(TMP);
 }
 
 
-void Assembler::CompareObject(Register rd1, Register rd2,
-                              Register rn, const Object& object) {
-  ASSERT(!in_delay_slot_);
-  ASSERT(rn != TMP);
-  ASSERT(rd1 != TMP);
-  ASSERT(rd1 != rd2);
-  LoadObject(TMP, object);
-  slt(rd1, rn, TMP);
-  slt(rd2, TMP, rn);
-}
-
-
 // Preserves object and value registers.
 void Assembler::StoreIntoObjectFilterNoSmi(Register object,
                                            Register value,
                                            Label* no_update) {
   ASSERT(!in_delay_slot_);
   COMPILE_ASSERT((kNewObjectAlignmentOffset == kWordSize) &&
                  (kOldObjectAlignmentOffset == 0));
 
   // Write-barrier triggers if the value is in the new space (has bit set) and
   // the object is in the old space (has bit cleared).
@@ skipping 730 matching lines @@
   Emit(reinterpret_cast<int32_t>(message));
   Bind(&stop);
   break_(Instr::kStopMessageCode);
 }
 
 
 void Assembler::TraceSimMsg(const char* message) {
   // Don't bother adding in the messages unless tracing is enabled, and we are
   // running in the simulator.
 #if defined(USING_SIMULATOR)
-  if (FLAG_trace_sim) {
+  if (FLAG_trace_sim_after != -1) {
     Label msg;
     b(&msg);
     Emit(reinterpret_cast<int32_t>(message));
     Bind(&msg);
     break_(Instr::kSimulatorMessageCode);
   }
 #endif
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS