Add disassembler to MIPS.

Patch by Vladimir Medic. 



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154935 91177308-0d34-0410-b5e6-96231b3b80d8

21 files changed, 2914 insertions, 93 deletions

diff --git a/lib/Target/Mips/CMakeLists.txt b/lib/Target/Mips/CMakeLists.txt
index 13d17e4e52..0500c5dc38 100644
--- a/lib/Target/Mips/CMakeLists.txt
+++ b/lib/Target/Mips/CMakeLists.txt
@@ -2,12 +2,14 @@ set(LLVM_TARGET_DEFINITIONS Mips.td)
 
 tablegen(LLVM MipsGenRegisterInfo.inc -gen-register-info)
 tablegen(LLVM MipsGenInstrInfo.inc -gen-instr-info)
+tablegen(LLVM MipsGenDisassemblerTables.inc -gen-disassembler)
 tablegen(LLVM MipsGenCodeEmitter.inc -gen-emitter)
 tablegen(LLVM MipsGenMCCodeEmitter.inc -gen-emitter -mc-emitter)
 tablegen(LLVM MipsGenAsmWriter.inc -gen-asm-writer)
 tablegen(LLVM MipsGenDAGISel.inc -gen-dag-isel)
 tablegen(LLVM MipsGenCallingConv.inc -gen-callingconv)
 tablegen(LLVM MipsGenSubtargetInfo.inc -gen-subtarget)
+tablegen(LLVM MipsGenEDInfo.inc -gen-enhanced-disassembly-info)
 add_public_tablegen_target(MipsCommonTableGen)
 
 add_llvm_target(MipsCodeGen
@@ -32,6 +34,7 @@ add_llvm_target(MipsCodeGen
   )
 
 add_subdirectory(InstPrinter)
+add_subdirectory(Disassembler)
 add_subdirectory(TargetInfo)
 add_subdirectory(MCTargetDesc)
 add_subdirectory(AsmParser)
diff --git a/lib/Target/Mips/Disassembler/CMakeLists.txt b/lib/Target/Mips/Disassembler/CMakeLists.txt
new file mode 100644
index 0000000000..4b2f6be49e
--- /dev/null
+++ b/lib/Target/Mips/Disassembler/CMakeLists.txt
@@ -0,0 +1,30 @@
+include_directories( ${CMAKE_CURRENT_BINARY_DIR}/.. ${CMAKE_CURRENT_SOURCE_DIR}/.. )
+
+add_llvm_library(LLVMMipsDisassembler
+  MipsDisassembler.cpp
+  )
+
+# workaround for hanging compilation on MSVC9 and 10
+if( MSVC_VERSION EQUAL 1400 OR MSVC_VERSION EQUAL 1500 OR MSVC_VERSION EQUAL 1600 )
+set_property(
+  SOURCE MipsDisassembler.cpp
+  PROPERTY COMPILE_FLAGS "/Od"
+  )
+endif()
+
+add_dependencies(LLVMMipsDisassembler MipsCommonTableGen)
+include_directories( ${CMAKE_CURRENT_BINARY_DIR}/.. ${CMAKE_CURRENT_SOURCE_DIR}/.. )
+
+add_llvm_library(LLVMMipsDisassembler
+  MipsDisassembler.cpp
+  )
+
+# workaround for hanging compilation on MSVC9 and 10
+if( MSVC_VERSION EQUAL 1400 OR MSVC_VERSION EQUAL 1500 OR MSVC_VERSION EQUAL 1600 )
+set_property(
+  SOURCE MipsDisassembler.cpp
+  PROPERTY COMPILE_FLAGS "/Od"
+  )
+endif()
+
+add_dependencies(LLVMMipsDisassembler MipsCommonTableGen)
diff --git a/lib/Target/Mips/Disassembler/LLVMBuild.txt b/lib/Target/Mips/Disassembler/LLVMBuild.txt
new file mode 100644
index 0000000000..048ad0ddac
--- /dev/null
+++ b/lib/Target/Mips/Disassembler/LLVMBuild.txt
@@ -0,0 +1,23 @@
+;===- ./lib/Target/Mips/Disassembler/LLVMBuild.txt --------------*- Conf -*--===;
+;
+;                     The LLVM Compiler Infrastructure
+;
+; This file is distributed under the University of Illinois Open Source
+; License. See LICENSE.TXT for details.
+;
+;===------------------------------------------------------------------------===;
+;
+; This is an LLVMBuild description file for the components in this subdirectory.
+;
+; For more information on the LLVMBuild system, please see:
+;
+;   http://llvm.org/docs/LLVMBuild.html
+;
+;===------------------------------------------------------------------------===;
+
+[component_0]
+type = Library
+name = MipsDisassembler
+parent = Mips
+required_libraries = MC Support MipsInfo
+add_to_library_groups = Mips
diff --git a/lib/Target/Mips/Disassembler/Makefile b/lib/Target/Mips/Disassembler/Makefile
new file mode 100644
index 0000000000..a78feba1f8
--- /dev/null
+++ b/lib/Target/Mips/Disassembler/Makefile
@@ -0,0 +1,16 @@
+##===- lib/Target/Mips/Disassembler/Makefile ----------------*- Makefile -*-===##
+#
+#                     The LLVM Compiler Infrastructure
+#
+# This file is distributed under the University of Illinois Open Source
+# License. See LICENSE.TXT for details.
+#
+##===----------------------------------------------------------------------===##
+
+LEVEL = ../../../..
+LIBRARYNAME = LLVMMipsDisassembler
+
+# Hack: we need to include 'main' Mips target directory to grab private headers
+CPP.Flags += -I$(PROJ_OBJ_DIR)/.. -I$(PROJ_SRC_DIR)/..
+
+include $(LEVEL)/Makefile.common
diff --git a/lib/Target/Mips/Disassembler/MipsDisassembler.cpp b/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
new file mode 100644
index 0000000000..78dbc06949
--- /dev/null
+++ b/lib/Target/Mips/Disassembler/MipsDisassembler.cpp
@@ -0,0 +1,552 @@
+//===- MipsDisassembler.cpp - Disassembler for Mips -------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is part of the Mips Disassembler.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Mips.h"
+#include "MipsSubtarget.h"
+#include "llvm/MC/EDInstInfo.h"
+#include "llvm/MC/MCDisassembler.h"
+#include "llvm/Support/MemoryObject.h"
+#include "llvm/Support/TargetRegistry.h"
+#include "llvm/MC/MCSubtargetInfo.h"
+#include "llvm/MC/MCInst.h"
+#include "llvm/MC/MCRegisterInfo.h"
+#include "llvm/Support/MathExtras.h"
+
+
+#include "MipsGenEDInfo.inc"
+
+using namespace llvm;
+
+typedef MCDisassembler::DecodeStatus DecodeStatus;
+
+/// MipsDisassembler - a disasembler class for Mips32.
+class MipsDisassembler : public MCDisassembler {
+public:
+  /// Constructor     - Initializes the disassembler.
+  ///
+  MipsDisassembler(const MCSubtargetInfo &STI, bool bigEndian) :
+    MCDisassembler(STI), isBigEndian(bigEndian) {
+  }
+
+  ~MipsDisassembler() {
+  }
+
+  /// getInstruction - See MCDisassembler.
+  DecodeStatus getInstruction(MCInst &instr,
+                              uint64_t &size,
+                              const MemoryObject &region,
+                              uint64_t address,
+                              raw_ostream &vStream,
+                              raw_ostream &cStream) const;
+
+  /// getEDInfo - See MCDisassembler.
+  const EDInstInfo *getEDInfo() const;
+
+private:
+  bool isBigEndian;
+};
+
+
+/// Mips64Disassembler - a disasembler class for Mips64.
+class Mips64Disassembler : public MCDisassembler {
+public:
+  /// Constructor     - Initializes the disassembler.
+  ///
+  Mips64Disassembler(const MCSubtargetInfo &STI, bool bigEndian) :
+    MCDisassembler(STI), isBigEndian(bigEndian) {
+  }
+
+  ~Mips64Disassembler() {
+  }
+
+  /// getInstruction - See MCDisassembler.
+  DecodeStatus getInstruction(MCInst &instr,
+                              uint64_t &size,
+                              const MemoryObject &region,
+                              uint64_t address,
+                              raw_ostream &vStream,
+                              raw_ostream &cStream) const;
+
+  /// getEDInfo - See MCDisassembler.
+  const EDInstInfo *getEDInfo() const;
+
+private:
+  bool isBigEndian;
+};
+
+const EDInstInfo *MipsDisassembler::getEDInfo() const {
+  return instInfoMips;
+}
+
+const EDInstInfo *Mips64Disassembler::getEDInfo() const {
+  return instInfoMips;
+}
+
+// Decoder tables for Mips register
+static const unsigned CPURegsTable[] = {
+  Mips::ZERO, Mips::AT, Mips::V0, Mips::V1,
+  Mips::A0, Mips::A1, Mips::A2, Mips::A3,
+  Mips::T0, Mips::T1, Mips::T2, Mips::T3,
+  Mips::T4, Mips::T5, Mips::T6, Mips::T7,
+  Mips::S0, Mips::S1, Mips::S2, Mips::S3,
+  Mips::S4, Mips::S5, Mips::S6, Mips::S7,
+  Mips::T8, Mips::T9, Mips::K0, Mips::K1,
+  Mips::GP, Mips::SP, Mips::FP, Mips::RA
+};
+
+static const unsigned FGR32RegsTable[] = {
+  Mips::F0, Mips::F1, Mips::F2, Mips::F3,
+  Mips::F4, Mips::F5, Mips::F6, Mips::F7,
+  Mips::F8, Mips::F9, Mips::F10, Mips::F11,
+  Mips::F12, Mips::F13, Mips::F14, Mips::F15,
+  Mips::F16, Mips::F17, Mips::F18, Mips::F18,
+  Mips::F20, Mips::F21, Mips::F22, Mips::F23,
+  Mips::F24, Mips::F25, Mips::F26, Mips::F27,
+  Mips::F28, Mips::F29, Mips::F30, Mips::F31
+};
+
+static const unsigned CPU64RegsTable[] = {
+  Mips::ZERO_64, Mips::AT_64, Mips::V0_64, Mips::V1_64,
+  Mips::A0_64, Mips::A1_64, Mips::A2_64, Mips::A3_64,
+  Mips::T0_64, Mips::T1_64, Mips::T2_64, Mips::T3_64,
+  Mips::T4_64, Mips::T5_64, Mips::T6_64, Mips::T7_64,
+  Mips::S0_64, Mips::S1_64, Mips::S2_64, Mips::S3_64,
+  Mips::S4_64, Mips::S5_64, Mips::S6_64, Mips::S7_64,
+  Mips::T8_64, Mips::T9_64, Mips::K0_64, Mips::K1_64,
+  Mips::GP_64, Mips::SP_64, Mips::FP_64, Mips::RA_64
+};
+
+static const unsigned FGR64RegsTable[] = {
+  Mips::D0_64,  Mips::D1_64,  Mips::D2_64,  Mips::D3_64,
+  Mips::D4_64,  Mips::D5_64,  Mips::D6_64,  Mips::D7_64,
+  Mips::D8_64,  Mips::D9_64,  Mips::D10_64, Mips::D11_64,
+  Mips::D12_64, Mips::D13_64, Mips::D14_64, Mips::D15_64,
+  Mips::D16_64, Mips::D17_64, Mips::D18_64, Mips::D19_64,
+  Mips::D20_64, Mips::D21_64, Mips::D22_64, Mips::D23_64,
+  Mips::D24_64, Mips::D25_64, Mips::D26_64, Mips::D27_64,
+  Mips::D28_64, Mips::D29_64, Mips::D30_64, Mips::D31_64
+};
+
+static const unsigned AFGR64RegsTable[] = {
+  Mips::D0,  Mips::D1,  Mips::D2,  Mips::D3,
+  Mips::D4,  Mips::D5,  Mips::D6,  Mips::D7,
+  Mips::D8,  Mips::D9,  Mips::D10, Mips::D11,
+  Mips::D12, Mips::D13, Mips::D14, Mips::D15
+};
+
+// Forward declare these because the autogenerated code will reference them.
+// Definitions are further down.
+static DecodeStatus DecodeCPU64RegsRegisterClass(MCInst &Inst,
+                                                 unsigned RegNo,
+                                                 uint64_t Address,
+                                                 const void *Decoder);
+
+static DecodeStatus DecodeCPURegsRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder);
+
+static DecodeStatus DecodeFGR64RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder);
+
+static DecodeStatus DecodeFGR32RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder);
+
+static DecodeStatus DecodeCCRRegisterClass(MCInst &Inst,
+                                           unsigned RegNo,
+                                           uint64_t Address,
+                                           const void *Decoder);
+
+static DecodeStatus DecodeHWRegsRegisterClass(MCInst &Inst,
+                                              unsigned Insn,
+                                              uint64_t Address,
+                                              const void *Decoder);
+
+static DecodeStatus DecodeAFGR64RegisterClass(MCInst &Inst,
+                                              unsigned RegNo,
+                                              uint64_t Address,
+                                              const void *Decoder);
+
+static DecodeStatus DecodeHWRegs64RegisterClass(MCInst &Inst,
+                                                unsigned Insn,
+                                                uint64_t Address,
+                                                const void *Decoder);
+
+static DecodeStatus DecodeBranchTarget(MCInst &Inst,
+                                       unsigned Offset,
+                                       uint64_t Address,
+                                       const void *Decoder);
+
+static DecodeStatus DecodeBC1(MCInst &Inst,
+                              unsigned Insn,
+                              uint64_t Address,
+                              const void *Decoder);
+
+
+static DecodeStatus DecodeJumpTarget(MCInst &Inst,
+                                     unsigned Insn,
+                                     uint64_t Address,
+                                     const void *Decoder);
+
+static DecodeStatus DecodeMem(MCInst &Inst,
+                              unsigned Insn,
+                              uint64_t Address,
+                              const void *Decoder);
+
+static DecodeStatus DecodeFMem(MCInst &Inst, unsigned Insn,
+                               uint64_t Address,
+                               const void *Decoder);
+
+static DecodeStatus DecodeSimm16(MCInst &Inst,
+                                 unsigned Insn,
+                                 uint64_t Address,
+                                 const void *Decoder);
+
+static DecodeStatus DecodeCondCode(MCInst &Inst,
+                                   unsigned Insn,
+                                   uint64_t Address,
+                                   const void *Decoder);
+
+static DecodeStatus DecodeInsSize(MCInst &Inst,
+                                  unsigned Insn,
+                                  uint64_t Address,
+                                  const void *Decoder);
+
+static DecodeStatus DecodeExtSize(MCInst &Inst,
+                                  unsigned Insn,
+                                  uint64_t Address,
+                                  const void *Decoder);
+
+namespace llvm {
+extern Target TheMipselTarget, TheMipsTarget, TheMips64Target,
+              TheMips64elTarget;
+}
+
+static MCDisassembler *createMipsDisassembler(
+                       const Target &T,
+                       const MCSubtargetInfo &STI) {
+  return new MipsDisassembler(STI,true);
+}
+
+static MCDisassembler *createMipselDisassembler(
+                       const Target &T,
+                       const MCSubtargetInfo &STI) {
+  return new MipsDisassembler(STI,false);
+}
+
+static MCDisassembler *createMips64Disassembler(
+                       const Target &T,
+                       const MCSubtargetInfo &STI) {
+  return new Mips64Disassembler(STI,true);
+}
+
+static MCDisassembler *createMips64elDisassembler(
+                       const Target &T,
+                       const MCSubtargetInfo &STI) {
+  return new Mips64Disassembler(STI, false);
+}
+
+extern "C" void LLVMInitializeMipsDisassembler() {
+  // Register the disassembler.
+  TargetRegistry::RegisterMCDisassembler(TheMipsTarget,
+                                         createMipsDisassembler);
+  TargetRegistry::RegisterMCDisassembler(TheMipselTarget,
+                                         createMipselDisassembler);
+  TargetRegistry::RegisterMCDisassembler(TheMips64Target,
+                                         createMips64Disassembler);
+  TargetRegistry::RegisterMCDisassembler(TheMips64elTarget,
+                                         createMips64elDisassembler);
+}
+
+
+#include "MipsGenDisassemblerTables.inc"
+
+  /// readInstruction - read four bytes from the MemoryObject
+  /// and return 32 bit word sorted according to the given endianess
+static DecodeStatus readInstruction32(const MemoryObject &region,
+                                      uint64_t address,
+                                      uint64_t &size,
+                                      uint32_t &insn,
+                                      bool isBigEndian) {
+  uint8_t Bytes[4];
+
+  // We want to read exactly 4 Bytes of data.
+  if (region.readBytes(address, 4, (uint8_t*)Bytes, NULL) == -1) {
+    size = 0;
+    return MCDisassembler::Fail;
+  }
+
+  if (isBigEndian) {
+    // Encoded as a big-endian 32-bit word in the stream.
+    insn = (Bytes[3] <<  0) |
+           (Bytes[2] <<  8) |
+           (Bytes[1] << 16) |
+           (Bytes[0] << 24);
+  }
+  else {
+    // Encoded as a small-endian 32-bit word in the stream.
+    insn = (Bytes[0] <<  0) |
+           (Bytes[1] <<  8) |
+           (Bytes[2] << 16) |
+           (Bytes[3] << 24);
+  }
+
+  return MCDisassembler::Success;
+}
+
+DecodeStatus
+MipsDisassembler::getInstruction(MCInst &instr,
+                                 uint64_t &Size,
+                                 const MemoryObject &Region,
+                                 uint64_t Address,
+                                 raw_ostream &vStream,
+                                 raw_ostream &cStream) const {
+  uint32_t Insn;
+
+  DecodeStatus Result = readInstruction32(Region, Address, Size,
+                                          Insn, isBigEndian);
+  if (Result == MCDisassembler::Fail)
+    return MCDisassembler::Fail;
+
+  // Calling the auto-generated decoder function.
+  Result = decodeMipsInstruction32(instr, Insn, Address, this, STI);
+  if (Result != MCDisassembler::Fail) {
+    Size = 4;
+    return Result;
+  }
+
+  return MCDisassembler::Fail;
+}
+
+DecodeStatus
+Mips64Disassembler::getInstruction(MCInst &instr,
+                                   uint64_t &Size,
+                                   const MemoryObject &Region,
+                                   uint64_t Address,
+                                   raw_ostream &vStream,
+                                   raw_ostream &cStream) const {
+  uint32_t Insn;
+
+  DecodeStatus Result = readInstruction32(Region, Address, Size,
+                                          Insn, isBigEndian);
+  if (Result == MCDisassembler::Fail)
+    return MCDisassembler::Fail;
+
+  // Calling the auto-generated decoder function.
+  Result = decodeMips64Instruction32(instr, Insn, Address, this, STI);
+  if (Result != MCDisassembler::Fail) {
+    Size = 4;
+    return Result;
+  }
+  // If we fail to decode in Mips64 decoder space we can try in Mips32
+  Result = decodeMipsInstruction32(instr, Insn, Address, this, STI);
+  if (Result != MCDisassembler::Fail) {
+    Size = 4;
+    return Result;
+  }
+
+  return MCDisassembler::Fail;
+}
+
+static DecodeStatus DecodeCPU64RegsRegisterClass(MCInst &Inst,
+                                                 unsigned RegNo,
+                                                 uint64_t Address,
+                                                 const void *Decoder) {
+
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  Inst.addOperand(MCOperand::CreateReg(CPU64RegsTable[RegNo]));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeCPURegsRegisterClass(MCInst &Inst,
+                                               unsigned RegNo,
+                                               uint64_t Address,
+                                               const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  Inst.addOperand(MCOperand::CreateReg(CPURegsTable[RegNo]));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeFGR64RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  Inst.addOperand(MCOperand::CreateReg(FGR64RegsTable[RegNo]));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeFGR32RegisterClass(MCInst &Inst,
+                                             unsigned RegNo,
+                                             uint64_t Address,
+                                             const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  Inst.addOperand(MCOperand::CreateReg(FGR32RegsTable[RegNo]));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeCCRRegisterClass(MCInst &Inst,
+                                           unsigned RegNo,
+                                           uint64_t Address,
+                                           const void *Decoder) {
+  Inst.addOperand(MCOperand::CreateReg(RegNo));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeMem(MCInst &Inst,
+                              unsigned Insn,
+                              uint64_t Address,
+                              const void *Decoder) {
+  int Offset = SignExtend32<16>(Insn & 0xffff);
+  int Reg = (int)fieldFromInstruction32(Insn, 16, 5);
+  int Base = (int)fieldFromInstruction32(Insn, 21, 5);
+
+  if(Inst.getOpcode() == Mips::SC){
+    Inst.addOperand(MCOperand::CreateReg(CPURegsTable[Reg]));
+  }
+
+  Inst.addOperand(MCOperand::CreateReg(CPURegsTable[Reg]));
+  Inst.addOperand(MCOperand::CreateReg(CPURegsTable[Base]));
+  Inst.addOperand(MCOperand::CreateImm(Offset));
+
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeFMem(MCInst &Inst,
+                               unsigned Insn,
+                               uint64_t Address,
+                               const void *Decoder) {
+  int Offset = SignExtend32<16>(Insn & 0xffff);
+  int Reg = (int)fieldFromInstruction32(Insn, 16, 5);
+  int Base = (int)fieldFromInstruction32(Insn, 21, 5);
+
+  Inst.addOperand(MCOperand::CreateReg(FGR64RegsTable[Reg]));
+  Inst.addOperand(MCOperand::CreateReg(CPURegsTable[Base]));
+  Inst.addOperand(MCOperand::CreateImm(Offset));
+
+  return MCDisassembler::Success;
+}
+
+
+static DecodeStatus DecodeHWRegsRegisterClass(MCInst &Inst,
+                                              unsigned RegNo,
+                                              uint64_t Address,
+                                              const void *Decoder) {
+  // Currently only hardware register 29 is supported.
+  if (RegNo != 29)
+    return  MCDisassembler::Fail;
+  Inst.addOperand(MCOperand::CreateReg(Mips::HWR29));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeCondCode(MCInst &Inst,
+                                   unsigned Insn,
+                                   uint64_t Address,
+                                   const void *Decoder) {
+  int CondCode = Insn & 0xf;
+  Inst.addOperand(MCOperand::CreateImm(CondCode));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeAFGR64RegisterClass(MCInst &Inst,
+                                              unsigned RegNo,
+                                              uint64_t Address,
+                                              const void *Decoder) {
+  if (RegNo > 31)
+    return MCDisassembler::Fail;
+
+  Inst.addOperand(MCOperand::CreateReg(AFGR64RegsTable[RegNo]));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeHWRegs64RegisterClass(MCInst &Inst,
+                                                unsigned RegNo,
+                                                uint64_t Address,
+                                                const void *Decoder) {
+  //Currently only hardware register 29 is supported
+  if (RegNo != 29)
+    return  MCDisassembler::Fail;
+  Inst.addOperand(MCOperand::CreateReg(Mips::HWR29));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeBranchTarget(MCInst &Inst,
+                                       unsigned Offset,
+                                       uint64_t Address,
+                                       const void *Decoder) {
+  unsigned BranchOffset = Offset & 0xffff;
+  BranchOffset = SignExtend32<18>(BranchOffset << 2) + 4;
+  Inst.addOperand(MCOperand::CreateImm(BranchOffset));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeBC1(MCInst &Inst,
+                              unsigned Insn,
+                              uint64_t Address,
+                              const void *Decoder) {
+  unsigned BranchOffset = Insn & 0xffff;
+  BranchOffset = SignExtend32<18>(BranchOffset << 2) + 4;
+  Inst.addOperand(MCOperand::CreateImm(BranchOffset));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeJumpTarget(MCInst &Inst,
+                                     unsigned Insn,
+                                     uint64_t Address,
+                                     const void *Decoder) {
+
+  unsigned JumpOffset = fieldFromInstruction32(Insn, 0, 26) << 2;
+  Inst.addOperand(MCOperand::CreateImm(JumpOffset));
+  return MCDisassembler::Success;
+}
+
+
+static DecodeStatus DecodeSimm16(MCInst &Inst,
+                                 unsigned Insn,
+                                 uint64_t Address,
+                                 const void *Decoder) {
+  Inst.addOperand(MCOperand::CreateImm(SignExtend32<16>(Insn)));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeInsSize(MCInst &Inst,
+                                  unsigned Insn,
+                                  uint64_t Address,
+                                  const void *Decoder) {
+  // First we need to grab the pos(lsb) from MCInst.
+  int Pos = Inst.getOperand(2).getImm();
+  int Size = (int) Insn - Pos + 1;
+  Inst.addOperand(MCOperand::CreateImm(SignExtend32<16>(Size)));
+  return MCDisassembler::Success;
+}
+
+static DecodeStatus DecodeExtSize(MCInst &Inst,
+                                  unsigned Insn,
+                                  uint64_t Address,
+                                  const void *Decoder) {
+  int Size = (int) Insn  + 1;
+  Inst.addOperand(MCOperand::CreateImm(SignExtend32<16>(Size)));
+  return MCDisassembler::Success;
+}
diff --git a/lib/Target/Mips/LLVMBuild.txt b/lib/Target/Mips/LLVMBuild.txt
index abbed8c90f..a95d6bc135 100644
--- a/lib/Target/Mips/LLVMBuild.txt
+++ b/lib/Target/Mips/LLVMBuild.txt
@@ -16,7 +16,7 @@
 ;===------------------------------------------------------------------------===;
 
 [common]
-subdirectories = AsmParser InstPrinter MCTargetDesc TargetInfo
+subdirectories = AsmParser Disassembler InstPrinter MCTargetDesc TargetInfo
 
 [component_0]
 type = TargetGroup
@@ -24,6 +24,7 @@ name = Mips
 parent = Target
 has_asmparser = 1
 has_asmprinter = 1
+has_disassembler = 1
 has_jit = 1
 
 [component_1]
diff --git a/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp b/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp
index 3c544f6aec..f634f082be 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp
@@ -34,6 +34,38 @@
 
 using namespace llvm;
 
+static std::string ParseMipsTriple(StringRef TT, StringRef CPU) {
+  std::string MipsArchFeature;
+  size_t DashPosition = 0;
+  StringRef TheTriple;
+
+  // Let's see if there is a dash, like mips-unknown-linux.
+  DashPosition = TT.find('-');
+
+  if (DashPosition == StringRef::npos) {
+    // No dash, we check the string size.
+    TheTriple = TT.substr(0);
+  } else {
+    // We are only interested in substring before dash.
+    TheTriple = TT.substr(0,DashPosition);
+  }
+
+  if (TheTriple == "mips" || TheTriple == "mipsel") {
+    if (CPU.empty() || CPU == "mips32") {
+      MipsArchFeature = "+mips32";
+    } else if (CPU == "mips32r2") {
+      MipsArchFeature = "+mips32r2";
+    }
+  } else {
+      if (CPU.empty() || CPU == "mips64") {
+        MipsArchFeature = "+mips64";
+      } else if (CPU == "mips64r2") {
+        MipsArchFeature = "+mips64r2";
+      }
+  }
+  return MipsArchFeature;
+}
+
 static MCInstrInfo *createMipsMCInstrInfo() {
   MCInstrInfo *X = new MCInstrInfo();
   InitMipsMCInstrInfo(X);
@@ -48,8 +80,15 @@ static MCRegisterInfo *createMipsMCRegisterInfo(StringRef TT) {
 
 static MCSubtargetInfo *createMipsMCSubtargetInfo(StringRef TT, StringRef CPU,
                                                   StringRef FS) {
+  std::string ArchFS = ParseMipsTriple(TT,CPU);
+  if (!FS.empty()) {
+    if (!ArchFS.empty())
+      ArchFS = ArchFS + "," + FS.str();
+    else
+      ArchFS = FS;
+  }
   MCSubtargetInfo *X = new MCSubtargetInfo();
-  InitMipsMCSubtargetInfo(X, TT, CPU, FS);
+  InitMipsMCSubtargetInfo(X, TT, CPU, ArchFS);
   return X;
 }
 
diff --git a/lib/Target/Mips/Makefile b/lib/Target/Mips/Makefile
index 168635c96b..596f07145a 100644
--- a/lib/Target/Mips/Makefile
+++ b/lib/Target/Mips/Makefile
@@ -15,9 +15,9 @@ TARGET = Mips
 BUILT_SOURCES = MipsGenRegisterInfo.inc MipsGenInstrInfo.inc \
                 MipsGenAsmWriter.inc MipsGenCodeEmitter.inc \
                 MipsGenDAGISel.inc MipsGenCallingConv.inc \
-                MipsGenSubtargetInfo.inc MipsGenMCCodeEmitter.inc
-
-DIRS = InstPrinter AsmParser TargetInfo MCTargetDesc
+                MipsGenSubtargetInfo.inc MipsGenMCCodeEmitter.inc \
+                MipsGenEDInfo.inc MipsGenDisassemblerTables.inc
+DIRS = InstPrinter Disassembler AsmParser TargetInfo MCTargetDesc
 
 include $(LEVEL)/Makefile.common
 
diff --git a/lib/Target/Mips/Mips64InstrInfo.td b/lib/Target/Mips/Mips64InstrInfo.td
index 427e8d97ad..c31ff0b9e7 100644
--- a/lib/Target/Mips/Mips64InstrInfo.td
+++ b/lib/Target/Mips/Mips64InstrInfo.td
@@ -36,6 +36,7 @@ def immZExt6 : ImmLeaf<i32, [{return Imm == (Imm & 0x3f);}]>;
 //===----------------------------------------------------------------------===//
 // Shifts
 // 64-bit shift instructions.
+let DecoderNamespace = "Mips64" in {
 class shift_rotate_imm64<bits<6> func, bits<5> isRotate, string instr_asm,
                          SDNode OpNode>:
   shift_rotate_imm<func, isRotate, instr_asm, OpNode, immZExt6, shamt,
@@ -49,16 +50,21 @@ class Div64<SDNode op, bits<6> func, string instr_asm, InstrItinClass itin>:
 
 multiclass Atomic2Ops64<PatFrag Op, string Opstr> {
   def #NAME# : Atomic2Ops<Op, Opstr, CPU64Regs, CPURegs>, Requires<[NotN64]>;
-  def _P8    : Atomic2Ops<Op, Opstr, CPU64Regs, CPU64Regs>, Requires<[IsN64]>;
+  def _P8    : Atomic2Ops<Op, Opstr, CPU64Regs, CPU64Regs>, Requires<[IsN64]> {
+    let isCodeGenOnly = 1;
+  }
 }
 
 multiclass AtomicCmpSwap64<PatFrag Op, string Width>  {
   def #NAME# : AtomicCmpSwap<Op, Width, CPU64Regs, CPURegs>, Requires<[NotN64]>;
   def _P8    : AtomicCmpSwap<Op, Width, CPU64Regs, CPU64Regs>,
-               Requires<[IsN64]>;
+               Requires<[IsN64]> {
+    let isCodeGenOnly = 1;
+  }
 }
-
-let usesCustomInserter = 1, Predicates = [HasMips64] in {
+}
+let us