Adds native/leaf runtime call stub and redirection on MIPS.

runtime/vm/instructions_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"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/constants_mips.h"
 #include "vm/instructions.h"
 #include "vm/object.h"
@@ skipping 144 matching lines @@
   const Smi& smi = Smi::Handle(reinterpret_cast<RawSmi*>(target_address));
   object_pool_.SetAt(target_address_pool_index_, smi);
   // No need to flush the instruction cache, since the code is not modified.
 }
 
 
 JumpPattern::JumpPattern(uword pc) : pc_(pc) { }
 
 
 bool JumpPattern::IsValid() const {
-  UNIMPLEMENTED();
-  return false;
+  Instr* lui = Instr::At(pc_ + (0 * Instr::kInstrSize));
+  Instr* ori = Instr::At(pc_ + (1 * Instr::kInstrSize));
+  Instr* jr = Instr::At(pc_ + (2 * Instr::kInstrSize));
+  Instr* nop = Instr::At(pc_ + (3 * Instr::kInstrSize));
+  return (lui->OpcodeField() == LUI) &&
+         (ori->OpcodeField() == ORI) &&
+         (jr->OpcodeField() == SPECIAL) &&
+         (jr->FunctionField() == JR) &&
+         (nop->InstructionBits() == Instr::kNopInstruction);
 }
 
 
 uword JumpPattern::TargetAddress() const {
-  UNIMPLEMENTED();
-  return 0;
+  Instr* lui = Instr::At(pc_ + (0 * Instr::kInstrSize));
+  Instr* ori = Instr::At(pc_ + (1 * Instr::kInstrSize));
+  const uint16_t target_lo = ori->UImmField();
+  const uint16_t target_hi = lui->UImmField();
+  return (target_hi << 16) | target_lo;
 }
 
 
 void JumpPattern::SetTargetAddress(uword target_address) const {
-  UNIMPLEMENTED();
+  Instr* lui = Instr::At(pc_ + (0 * Instr::kInstrSize));
+  Instr* ori = Instr::At(pc_ + (1 * Instr::kInstrSize));
+  const int32_t lui_bits = lui->InstructionBits();
+  const int32_t ori_bits = ori->InstructionBits();
+  const uint16_t target_lo = target_address & 0xffff;
+  const uint16_t target_hi = target_address >> 16;
+
+  lui->SetInstructionBits((lui_bits & 0xffff0000) | target_hi);
+  ori->SetInstructionBits((ori_bits & 0xffff0000) | target_lo);
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS