diff --git a/compiler/utils/assembler.h b/compiler/utils/assembler.h
new file mode 100644
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+++ b/compiler/utils/assembler.h
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+/*
+ * Copyright (C) 2011 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ART_COMPILER_UTILS_ASSEMBLER_H_
+#define ART_COMPILER_UTILS_ASSEMBLER_H_
+
+#include <vector>
+
+#include "base/logging.h"
+#include "base/macros.h"
+#include "arm/constants_arm.h"
+#include "mips/constants_mips.h"
+#include "x86/constants_x86.h"
+#include "instruction_set.h"
+#include "managed_register.h"
+#include "memory_region.h"
+#include "offsets.h"
+
+namespace art {
+
+class Assembler;
+class AssemblerBuffer;
+class AssemblerFixup;
+
+namespace arm {
+  class ArmAssembler;
+}
+namespace mips {
+  class MipsAssembler;
+}
+namespace x86 {
+  class X86Assembler;
+}
+
+class Label {
+ public:
+  Label() : position_(0) {}
+
+  ~Label() {
+    // Assert if label is being destroyed with unresolved branches pending.
+    CHECK(!IsLinked());
+  }
+
+  // Returns the position for bound and linked labels. Cannot be used
+  // for unused labels.
+  int Position() const {
+    CHECK(!IsUnused());
+    return IsBound() ? -position_ - kPointerSize : position_ - kPointerSize;
+  }
+
+  int LinkPosition() const {
+    CHECK(IsLinked());
+    return position_ - kWordSize;
+  }
+
+  bool IsBound() const { return position_ < 0; }
+  bool IsUnused() const { return position_ == 0; }
+  bool IsLinked() const { return position_ > 0; }
+
+ private:
+  int position_;
+
+  void Reinitialize() {
+    position_ = 0;
+  }
+
+  void BindTo(int position) {
+    CHECK(!IsBound());
+    position_ = -position - kPointerSize;
+    CHECK(IsBound());
+  }
+
+  void LinkTo(int position) {
+    CHECK(!IsBound());
+    position_ = position + kPointerSize;
+    CHECK(IsLinked());
+  }
+
+  friend class arm::ArmAssembler;
+  friend class mips::MipsAssembler;
+  friend class x86::X86Assembler;
+
+  DISALLOW_COPY_AND_ASSIGN(Label);
+};
+
+
+// Assembler fixups are positions in generated code that require processing
+// after the code has been copied to executable memory. This includes building
+// relocation information.
+class AssemblerFixup {
+ public:
+  virtual void Process(const MemoryRegion& region, int position) = 0;
+  virtual ~AssemblerFixup() {}
+
+ private:
+  AssemblerFixup* previous_;
+  int position_;
+
+  AssemblerFixup* previous() const { return previous_; }
+  void set_previous(AssemblerFixup* previous) { previous_ = previous; }
+
+  int position() const { return position_; }
+  void set_position(int position) { position_ = position; }
+
+  friend class AssemblerBuffer;
+};
+
+// Parent of all queued slow paths, emitted during finalization
+class SlowPath {
+ public:
+  SlowPath() : next_(NULL) {}
+  virtual ~SlowPath() {}
+
+  Label* Continuation() { return &continuation_; }
+  Label* Entry() { return &entry_; }
+  // Generate code for slow path
+  virtual void Emit(Assembler *sp_asm) = 0;
+
+ protected:
+  // Entry branched to by fast path
+  Label entry_;
+  // Optional continuation that is branched to at the end of the slow path
+  Label continuation_;
+  // Next in linked list of slow paths
+  SlowPath *next_;
+
+  friend class AssemblerBuffer;
+  DISALLOW_COPY_AND_ASSIGN(SlowPath);
+};
+
+class AssemblerBuffer {
+ public:
+  AssemblerBuffer();
+  ~AssemblerBuffer();
+
+  // Basic support for emitting, loading, and storing.
+  template<typename T> void Emit(T value) {
+    CHECK(HasEnsuredCapacity());
+    *reinterpret_cast<T*>(cursor_) = value;
+    cursor_ += sizeof(T);
+  }
+
+  template<typename T> T Load(size_t position) {
+    CHECK_LE(position, Size() - static_cast<int>(sizeof(T)));
+    return *reinterpret_cast<T*>(contents_ + position);
+  }
+
+  template<typename T> void Store(size_t position, T value) {
+    CHECK_LE(position, Size() - static_cast<int>(sizeof(T)));
+    *reinterpret_cast<T*>(contents_ + position) = value;
+  }
+
+  // Emit a fixup at the current location.
+  void EmitFixup(AssemblerFixup* fixup) {
+    fixup->set_previous(fixup_);
+    fixup->set_position(Size());
+    fixup_ = fixup;
+  }
+
+  void EnqueueSlowPath(SlowPath* slowpath) {
+    if (slow_path_ == NULL) {
+      slow_path_ = slowpath;
+    } else {
+      SlowPath* cur = slow_path_;
+      for ( ; cur->next_ != NULL ; cur = cur->next_) {}
+      cur->next_ = slowpath;
+    }
+  }
+
+  void EmitSlowPaths(Assembler* sp_asm) {
+    SlowPath* cur = slow_path_;
+    SlowPath* next = NULL;
+    slow_path_ = NULL;
+    for ( ; cur != NULL ; cur = next) {
+      cur->Emit(sp_asm);
+      next = cur->next_;
+      delete cur;
+    }
+  }
+
+  // Get the size of the emitted code.
+  size_t Size() const {
+    CHECK_GE(cursor_, contents_);
+    return cursor_ - contents_;
+  }
+
+  byte* contents() const { return contents_; }
+
+  // Copy the assembled instructions into the specified memory block
+  // and apply all fixups.
+  void FinalizeInstructions(const MemoryRegion& region);
+
+  // To emit an instruction to the assembler buffer, the EnsureCapacity helper
+  // must be used to guarantee that the underlying data area is big enough to
+  // hold the emitted instruction. Usage:
+  //
+  //     AssemblerBuffer buffer;
+  //     AssemblerBuffer::EnsureCapacity ensured(&buffer);
+  //     ... emit bytes for single instruction ...
+
+#ifndef NDEBUG
+
+  class EnsureCapacity {
+   public:
+    explicit EnsureCapacity(AssemblerBuffer* buffer) {
+      if (buffer->cursor() >= buffer->limit()) {
+        buffer->ExtendCapacity();
+      }
+      // In debug mode, we save the assembler buffer along with the gap
+      // size before we start emitting to the buffer. This allows us to
+      // check that any single generated instruction doesn't overflow the
+      // limit implied by the minimum gap size.
+      buffer_ = buffer;
+      gap_ = ComputeGap();
+      // Make sure that extending the capacity leaves a big enough gap
+      // for any kind of instruction.
+      CHECK_GE(gap_, kMinimumGap);
+      // Mark the buffer as having ensured the capacity.
+      CHECK(!buffer->HasEnsuredCapacity());  // Cannot nest.
+      buffer->has_ensured_capacity_ = true;
+    }
+
+    ~EnsureCapacity() {
+      // Unmark the buffer, so we cannot emit after this.
+      buffer_->has_ensured_capacity_ = false;
+      // Make sure the generated instruction doesn't take up more
+      // space than the minimum gap.
+      int delta = gap_ - ComputeGap();
+      CHECK_LE(delta, kMinimumGap);
+    }
+
+   private:
+    AssemblerBuffer* buffer_;
+    int gap_;
+
+    int ComputeGap() { return buffer_->Capacity() - buffer_->Size(); }
+  };
+
+  bool has_ensured_capacity_;
+  bool HasEnsuredCapacity() const { return has_ensured_capacity_; }
+
+#else
+
+  class EnsureCapacity {
+   public:
+    explicit EnsureCapacity(AssemblerBuffer* buffer) {
+      if (buffer->cursor() >= buffer->limit()) buffer->ExtendCapacity();
+    }
+  };
+
+  // When building the C++ tests, assertion code is enabled. To allow
+  // asserting that the user of the assembler buffer has ensured the
+  // capacity needed for emitting, we add a dummy method in non-debug mode.
+  bool HasEnsuredCapacity() const { return true; }
+
+#endif
+
+  // Returns the position in the instruction stream.
+  int GetPosition() { return  cursor_ - contents_; }
+
+ private:
+  // The limit is set to kMinimumGap bytes before the end of the data area.
+  // This leaves enough space for the longest possible instruction and allows
+  // for a single, fast space check per instruction.
+  static const int kMinimumGap = 32;
+
+  byte* contents_;
+  byte* cursor_;
+  byte* limit_;
+  AssemblerFixup* fixup_;
+  bool fixups_processed_;
+
+  // Head of linked list of slow paths
+  SlowPath* slow_path_;
+
+  byte* cursor() const { return cursor_; }
+  byte* limit() const { return limit_; }
+  size_t Capacity() const {
+    CHECK_GE(limit_, contents_);
+    return (limit_ - contents_) + kMinimumGap;
+  }
+
+  // Process the fixup chain starting at the given fixup. The offset is
+  // non-zero for fixups in the body if the preamble is non-empty.
+  void ProcessFixups(const MemoryRegion& region);
+
+  // Compute the limit based on the data area and the capacity. See
+  // description of kMinimumGap for the reasoning behind the value.
+  static byte* ComputeLimit(byte* data, size_t capacity) {
+    return data + capacity - kMinimumGap;
+  }
+
+  void ExtendCapacity();
+
+  friend class AssemblerFixup;
+};
+
+class Assembler {
+ public:
+  static Assembler* Create(InstructionSet instruction_set);
+
+  // Emit slow paths queued during assembly
+  void EmitSlowPaths() { buffer_.EmitSlowPaths(this); }
+
+  // Size of generated code
+  size_t CodeSize() const { return buffer_.Size(); }
+
+  // Copy instructions out of assembly buffer into the given region of memory
+  void FinalizeInstructions(const MemoryRegion& region) {
+    buffer_.FinalizeInstructions(region);
+  }
+
+  // Emit code that will create an activation on the stack
+  virtual void BuildFrame(size_t frame_size, ManagedRegister method_reg,
+                          const std::vector<ManagedRegister>& callee_save_regs,
+                          const std::vector<ManagedRegister>& entry_spills) = 0;
+
+  // Emit code that will remove an activation from the stack
+  virtual void RemoveFrame(size_t frame_size,
+                           const std::vector<ManagedRegister>& callee_save_regs) = 0;
+
+  virtual void IncreaseFrameSize(size_t adjust) = 0;
+  virtual void DecreaseFrameSize(size_t adjust) = 0;
+
+  // Store routines
+  virtual void Store(FrameOffset offs, ManagedRegister src, size_t size) = 0;
+  virtual void StoreRef(FrameOffset dest, ManagedRegister src) = 0;
+  virtual void StoreRawPtr(FrameOffset dest, ManagedRegister src) = 0;
+
+  virtual void StoreImmediateToFrame(FrameOffset dest, uint32_t imm,
+                                     ManagedRegister scratch) = 0;
+
+  virtual void StoreImmediateToThread(ThreadOffset dest, uint32_t imm,
+                                      ManagedRegister scratch) = 0;
+
+  virtual void StoreStackOffsetToThread(ThreadOffset thr_offs,
+                                        FrameOffset fr_offs,
+                                        ManagedRegister scratch) = 0;
+
+  virtual void StoreStackPointerToThread(ThreadOffset thr_offs) = 0;
+
+  virtual void StoreSpanning(FrameOffset dest, ManagedRegister src,
+                             FrameOffset in_off, ManagedRegister scratch) = 0;
+
+  // Load routines
+  virtual void Load(ManagedRegister dest, FrameOffset src, size_t size) = 0;
+
+  virtual void Load(ManagedRegister dest, ThreadOffset src, size_t size) = 0;
+
+  virtual void LoadRef(ManagedRegister dest, FrameOffset  src) = 0;
+
+  virtual void LoadRef(ManagedRegister dest, ManagedRegister base,
+                       MemberOffset offs) = 0;
+
+  virtual void LoadRawPtr(ManagedRegister dest, ManagedRegister base,
+                          Offset offs) = 0;
+
+  virtual void LoadRawPtrFromThread(ManagedRegister dest,
+                                    ThreadOffset offs) = 0;
+
+  // Copying routines
+  virtual void Move(ManagedRegister dest, ManagedRegister src, size_t size) = 0;
+
+  virtual void CopyRawPtrFromThread(FrameOffset fr_offs, ThreadOffset thr_offs,
+                                    ManagedRegister scratch) = 0;
+
+  virtual void CopyRawPtrToThread(ThreadOffset thr_offs, FrameOffset fr_offs,
+                                  ManagedRegister scratch) = 0;
+
+  virtual void CopyRef(FrameOffset dest, FrameOffset src,
+                       ManagedRegister scratch) = 0;
+
+  virtual void Copy(FrameOffset dest, FrameOffset src, ManagedRegister scratch, size_t size) = 0;
+
+  virtual void Copy(FrameOffset dest, ManagedRegister src_base, Offset src_offset,
+                    ManagedRegister scratch, size_t size) = 0;
+
+  virtual void Copy(ManagedRegister dest_base, Offset dest_offset, FrameOffset src,
+                    ManagedRegister scratch, size_t size) = 0;
+
+  virtual void Copy(FrameOffset dest, FrameOffset src_base, Offset src_offset,
+                    ManagedRegister scratch, size_t size) = 0;
+
+  virtual void Copy(ManagedRegister dest, Offset dest_offset,
+                    ManagedRegister src, Offset src_offset,
+                    ManagedRegister scratch, size_t size) = 0;
+
+  virtual void Copy(FrameOffset dest, Offset dest_offset, FrameOffset src, Offset src_offset,
+                    ManagedRegister scratch, size_t size) = 0;
+
+  virtual void MemoryBarrier(ManagedRegister scratch) = 0;
+
+  // Sign extension
+  virtual void SignExtend(ManagedRegister mreg, size_t size) = 0;
+
+  // Zero extension
+  virtual void ZeroExtend(ManagedRegister mreg, size_t size) = 0;
+
+  // Exploit fast access in managed code to Thread::Current()
+  virtual void GetCurrentThread(ManagedRegister tr) = 0;
+  virtual void GetCurrentThread(FrameOffset dest_offset,
+                                ManagedRegister scratch) = 0;
+
+  // Set up out_reg to hold a Object** into the SIRT, or to be NULL if the
+  // value is null and null_allowed. in_reg holds a possibly stale reference
+  // that can be used to avoid loading the SIRT entry to see if the value is
+  // NULL.
+  virtual void CreateSirtEntry(ManagedRegister out_reg, FrameOffset sirt_offset,
+                               ManagedRegister in_reg, bool null_allowed) = 0;
+
+  // Set up out_off to hold a Object** into the SIRT, or to be NULL if the
+  // value is null and null_allowed.
+  virtual void CreateSirtEntry(FrameOffset out_off, FrameOffset sirt_offset,
+                               ManagedRegister scratch, bool null_allowed) = 0;
+
+  // src holds a SIRT entry (Object**) load this into dst
+  virtual void LoadReferenceFromSirt(ManagedRegister dst,
+                                     ManagedRegister src) = 0;
+
+  // Heap::VerifyObject on src. In some cases (such as a reference to this) we
+  // know that src may not be null.
+  virtual void VerifyObject(ManagedRegister src, bool could_be_null) = 0;
+  virtual void VerifyObject(FrameOffset src, bool could_be_null) = 0;
+
+  // Call to address held at [base+offset]
+  virtual void Call(ManagedRegister base, Offset offset,
+                    ManagedRegister scratch) = 0;
+  virtual void Call(FrameOffset base, Offset offset,
+                    ManagedRegister scratch) = 0;
+  virtual void Call(ThreadOffset offset, ManagedRegister scratch) = 0;
+
+  // Generate code to check if Thread::Current()->exception_ is non-null
+  // and branch to a ExceptionSlowPath if it is.
+  virtual void ExceptionPoll(ManagedRegister scratch, size_t stack_adjust) = 0;
+
+  virtual ~Assembler() {}
+
+ protected:
+  Assembler() : buffer_() {}
+
+  AssemblerBuffer buffer_;
+};
+
+}  // namespace art
+
+#endif  // ART_COMPILER_UTILS_ASSEMBLER_H_