Adds support for UseDartApi vm test on MIPS.

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"
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/assembler.h"
 #include "vm/runtime_entry.h"
 #include "vm/simulator.h"
@@ skipping 99 matching lines @@
     and_(ro, ro, TMP1);
   } else {
     addu(rd, rs, rt);
     xor_(ro, rd, rs);
     xor_(TMP1, rd, rt);
     and_(ro, TMP1, ro);
   }
 }
 
 
+void Assembler::SubuDetectOverflow(Register rd, Register rs, Register rt,
+                                   Register ro) {
+  ASSERT(rd != ro);
+  ASSERT(rd != TMP1);
+  ASSERT(ro != TMP1);
+  ASSERT(ro != rs);
+  ASSERT(ro != rt);
+  ASSERT(rs != TMP1);
+  ASSERT(rt != TMP1);
+
+  // This happens with some crankshaft code. Since Subu works fine if
+  // left == right, let's not make that restriction here.
+  if (rs == rt) {
+    mov(rd, ZR);
+    mov(ro, ZR);
+    return;
+  }
+
+  if (rd == rs) {
+    mov(TMP1, rs);  // Preserve left.
+    subu(rd, rs, rt);  // Left is overwritten.
+    xor_(ro, rd, TMP1);  // scratch is original left.
+    xor_(TMP1, TMP1, rs);  // scratch is original left.
+    and_(ro, TMP1, ro);
+  } else if (rd == rt) {
+    mov(TMP1, rt);  // Preserve right.
+    subu(rd, rs, rt);  // Right is overwritten.
+    xor_(ro, rd, rs);
+    xor_(TMP1, rs, TMP1);  // Original right.
+    and_(ro, TMP1, ro);
+  } else {
+    subu(rd, rs, rt);
+    xor_(ro, rd, rs);
+    xor_(TMP1, rs, rt);
+    and_(ro, TMP1, ro);
+  }
+}
+
+
 void Assembler::LoadObject(Register rd, const Object& object) {
   // Smi's and VM heap objects are never relocated; do not use object pool.
   if (object.IsSmi()) {
     LoadImmediate(rd, reinterpret_cast<int32_t>(object.raw()));
   } else if (object.InVMHeap()) {
     // Make sure that class CallPattern is able to decode this load immediate.
     int32_t object_raw = reinterpret_cast<int32_t>(object.raw());
     const uint16_t object_low = Utils::Low16Bits(object_raw);
     const uint16_t object_high = Utils::High16Bits(object_raw);
     lui(rd, Immediate(object_high));
@@ skipping 216 matching lines @@
   b(&stop);
   Emit(reinterpret_cast<int32_t>(message));
   Bind(&stop);
   break_(Instr::kStopMessageCode);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS