runtime/dex_instruction.h - platform/art - Gitiles

 /*
  * 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_RUNTIME_DEX_INSTRUCTION_H_
 #define ART_RUNTIME_DEX_INSTRUCTION_H_

 #include "base/logging.h"
 #include "base/macros.h"
 #include "globals.h"

 typedef uint8_t uint4_t;
 typedef int8_t int4_t;

 namespace art {

 class DexFile;

 enum {
   kNumPackedOpcodes = 0x100
 };

 class Instruction {
  public:
   // NOP-encoded switch-statement signatures.
   enum {
     kPackedSwitchSignature = 0x0100,
     kSparseSwitchSignature = 0x0200,
     kArrayDataSignature = 0x0300,
   };

   struct PACKED(4) PackedSwitchPayload {
     const uint16_t ident;
     const uint16_t case_count;
     const int32_t first_key;
     const int32_t targets[];

    private:
     DISALLOW_COPY_AND_ASSIGN(PackedSwitchPayload);
   };

   struct PACKED(4) SparseSwitchPayload {
     const uint16_t ident;
     const uint16_t case_count;
     const int32_t keys_and_targets[];

    public:
     const int32_t* GetKeys() const {
       return keys_and_targets;
     }

     const int32_t* GetTargets() const {
       return keys_and_targets + case_count;
     }

    private:
     DISALLOW_COPY_AND_ASSIGN(SparseSwitchPayload);
   };

   struct PACKED(4) ArrayDataPayload {
     const uint16_t ident;
     const uint16_t element_width;
     const uint32_t element_count;
     const uint8_t data[];

    private:
     DISALLOW_COPY_AND_ASSIGN(ArrayDataPayload);
   };

   // TODO: the code layout below is deliberate to avoid this enum being picked up by
   //       generate-operator-out.py.
   enum Code
   {  // NOLINT(whitespace/braces)
 #define INSTRUCTION_ENUM(opcode, cname, p, f, r, i, a, v) cname = opcode,
 #include "dex_instruction_list.h"
     DEX_INSTRUCTION_LIST(INSTRUCTION_ENUM)
 #undef DEX_INSTRUCTION_LIST
 #undef INSTRUCTION_ENUM
   };

   enum Format {
     k10x,  // op
     k12x,  // op vA, vB
     k11n,  // op vA, #+B
     k11x,  // op vAA
     k10t,  // op +AA
     k20t,  // op +AAAA
     k22x,  // op vAA, vBBBB
     k21t,  // op vAA, +BBBB
     k21s,  // op vAA, #+BBBB
     k21h,  // op vAA, #+BBBB00000[00000000]
     k21c,  // op vAA, thing@BBBB
     k23x,  // op vAA, vBB, vCC
     k22b,  // op vAA, vBB, #+CC
     k22t,  // op vA, vB, +CCCC
     k22s,  // op vA, vB, #+CCCC
     k22c,  // op vA, vB, thing@CCCC
     k32x,  // op vAAAA, vBBBB
     k30t,  // op +AAAAAAAA
     k31t,  // op vAA, +BBBBBBBB
     k31i,  // op vAA, #+BBBBBBBB
     k31c,  // op vAA, thing@BBBBBBBB
     k35c,  // op {vC, vD, vE, vF, vG}, thing@BBBB (B: count, A: vG)
     k3rc,  // op {vCCCC .. v(CCCC+AA-1)}, meth@BBBB
     k51l,  // op vAA, #+BBBBBBBBBBBBBBBB
   };

   enum Flags {
     kBranch              = 0x000001,  // conditional or unconditional branch
     kContinue            = 0x000002,  // flow can continue to next statement
     kSwitch              = 0x000004,  // switch statement
     kThrow               = 0x000008,  // could cause an exception to be thrown
     kReturn              = 0x000010,  // returns, no additional statements
     kInvoke              = 0x000020,  // a flavor of invoke
     kUnconditional       = 0x000040,  // unconditional branch
     kAdd                 = 0x000080,  // addition
     kSubtract            = 0x000100,  // subtract
     kMultiply            = 0x000200,  // multiply
     kDivide              = 0x000400,  // division
     kRemainder           = 0x000800,  // remainder
     kAnd                 = 0x001000,  // and
     kOr                  = 0x002000,  // or
     kXor                 = 0x004000,  // xor
     kShl                 = 0x008000,  // shl
     kShr                 = 0x010000,  // shr
     kUshr                = 0x020000,  // ushr
     kCast                = 0x040000,  // cast
     kStore               = 0x080000,  // store opcode
     kLoad                = 0x100000,  // load opcode
     kClobber             = 0x200000,  // clobbers memory in a big way (not just a write)
     kRegCFieldOrConstant = 0x400000,  // is the third virtual register a field or literal constant (vC)
     kRegBFieldOrConstant = 0x800000,  // is the second virtual register a field or literal constant (vB)
   };

   enum VerifyFlag {
     kVerifyNone            = 0x000000,
     kVerifyRegA            = 0x000001,
     kVerifyRegAWide        = 0x000002,
     kVerifyRegB            = 0x000004,
     kVerifyRegBField       = 0x000008,
     kVerifyRegBMethod      = 0x000010,
     kVerifyRegBNewInstance = 0x000020,
     kVerifyRegBString      = 0x000040,
     kVerifyRegBType        = 0x000080,
     kVerifyRegBWide        = 0x000100,
     kVerifyRegC            = 0x000200,
     kVerifyRegCField       = 0x000400,
     kVerifyRegCNewArray    = 0x000800,
     kVerifyRegCType        = 0x001000,
     kVerifyRegCWide        = 0x002000,
     kVerifyArrayData       = 0x004000,
     kVerifyBranchTarget    = 0x008000,
     kVerifySwitchTargets   = 0x010000,
     kVerifyVarArg          = 0x020000,
     kVerifyVarArgRange     = 0x040000,
     kVerifyRuntimeOnly     = 0x080000,
     kVerifyError           = 0x100000,
   };

   static constexpr uint32_t kMaxVarArgRegs = 5;

   // Returns the size (in 2 byte code units) of this instruction.
   size_t SizeInCodeUnits() const {
     int result = kInstructionSizeInCodeUnits[Opcode()];
     if (UNLIKELY(result < 0)) {
       return SizeInCodeUnitsComplexOpcode();
     } else {
       return static_cast<size_t>(result);
     }
   }

   // Reads an instruction out of the stream at the specified address.
   static const Instruction* At(const uint16_t* code) {
     DCHECK(code != NULL);
     return reinterpret_cast<const Instruction*>(code);
   }

   // Reads an instruction out of the stream from the current address plus an offset.
   const Instruction* RelativeAt(int32_t offset) const {
     return At(reinterpret_cast<const uint16_t*>(this) + offset);
   }

   // Returns a pointer to the next instruction in the stream.
   const Instruction* Next() const {
     return RelativeAt(SizeInCodeUnits());
   }

   // Returns a pointer to the instruction after this 1xx instruction in the stream.
   const Instruction* Next_1xx() const {
     DCHECK(FormatOf(Opcode()) >= k10x && FormatOf(Opcode()) <= k10t);
     return RelativeAt(1);
   }

   // Returns a pointer to the instruction after this 2xx instruction in the stream.
   const Instruction* Next_2xx() const {
     DCHECK(FormatOf(Opcode()) >= k20t && FormatOf(Opcode()) <= k22c);
     return RelativeAt(2);
   }

   // Returns a pointer to the instruction after this 3xx instruction in the stream.
   const Instruction* Next_3xx() const {
     DCHECK(FormatOf(Opcode()) >= k32x && FormatOf(Opcode()) <= k3rc);
     return RelativeAt(3);
   }

   // Returns a pointer to the instruction after this 51l instruction in the stream.
   const Instruction* Next_51l() const {
     DCHECK(FormatOf(Opcode()) == k51l);
     return RelativeAt(5);
   }

   // Returns the name of this instruction's opcode.
   const char* Name() const {
     return Instruction::Name(Opcode());
   }

   // Returns the name of the given opcode.
   static const char* Name(Code opcode) {
     return kInstructionNames[opcode];
   }

   // VRegA
   bool HasVRegA() const;
   int32_t VRegA() const;

   int8_t VRegA_10t() const {
     return VRegA_10t(Fetch16(0));
   }
   uint8_t VRegA_10x() const {
     return VRegA_10x(Fetch16(0));
   }
   uint4_t VRegA_11n() const {
     return VRegA_11n(Fetch16(0));
   }
   uint8_t VRegA_11x() const {
     return VRegA_11x(Fetch16(0));
   }
   uint4_t VRegA_12x() const {
     return VRegA_12x(Fetch16(0));
   }
   int16_t VRegA_20t() const;
   uint8_t VRegA_21c() const {
     return VRegA_21c(Fetch16(0));
   }
   uint8_t VRegA_21h() const {
     return VRegA_21h(Fetch16(0));
   }
   uint8_t VRegA_21s() const {
     return VRegA_21s(Fetch16(0));
   }
   uint8_t VRegA_21t() const {
     return VRegA_21t(Fetch16(0));
   }
   uint8_t VRegA_22b() const {
     return VRegA_22b(Fetch16(0));
   }
   uint4_t VRegA_22c() const {
     return VRegA_22c(Fetch16(0));
   }
   uint4_t VRegA_22s() const {
     return VRegA_22s(Fetch16(0));
   }
   uint4_t VRegA_22t() const {
     return VRegA_22t(Fetch16(0));
   }
   uint8_t VRegA_22x() const {
     return VRegA_22x(Fetch16(0));
   }
   uint8_t VRegA_23x() const {
     return VRegA_23x(Fetch16(0));
   }
   int32_t VRegA_30t() const;
   uint8_t VRegA_31c() const {
     return VRegA_31c(Fetch16(0));
   }
   uint8_t VRegA_31i() const {
     return VRegA_31i(Fetch16(0));
   }
   uint8_t VRegA_31t() const {
     return VRegA_31t(Fetch16(0));
   }
   uint16_t VRegA_32x() const;
   uint4_t VRegA_35c() const {
     return VRegA_35c(Fetch16(0));
   }
   uint8_t VRegA_3rc() const {
     return VRegA_3rc(Fetch16(0));
   }
   uint8_t VRegA_51l() const {
     return VRegA_51l(Fetch16(0));
   }

   // The following methods return the vA operand for various instruction formats. The "inst_data"
   // parameter holds the first 16 bits of instruction which the returned value is decoded from.
   int8_t VRegA_10t(uint16_t inst_data) const;
   uint8_t VRegA_10x(uint16_t inst_data) const;
   uint4_t VRegA_11n(uint16_t inst_data) const;
   uint8_t VRegA_11x(uint16_t inst_data) const;
   uint4_t VRegA_12x(uint16_t inst_data) const;
   uint8_t VRegA_21c(uint16_t inst_data) const;
   uint8_t VRegA_21h(uint16_t inst_data) const;
   uint8_t VRegA_21s(uint16_t inst_data) const;
   uint8_t VRegA_21t(uint16_t inst_data) const;
   uint8_t VRegA_22b(uint16_t inst_data) const;
   uint4_t VRegA_22c(uint16_t inst_data) const;
   uint4_t VRegA_22s(uint16_t inst_data) const;
   uint4_t VRegA_22t(uint16_t inst_data) const;
   uint8_t VRegA_22x(uint16_t inst_data) const;
   uint8_t VRegA_23x(uint16_t inst_data) const;
   uint8_t VRegA_31c(uint16_t inst_data) const;
   uint8_t VRegA_31i(uint16_t inst_data) const;
   uint8_t VRegA_31t(uint16_t inst_data) const;
   uint4_t VRegA_35c(uint16_t inst_data) const;
   uint8_t VRegA_3rc(uint16_t inst_data) const;
   uint8_t VRegA_51l(uint16_t inst_data) const;

   // VRegB
   bool HasVRegB() const;
   int32_t VRegB() const;

   bool HasWideVRegB() const;
   uint64_t WideVRegB() const;

   int4_t VRegB_11n() const {
     return VRegB_11n(Fetch16(0));
   }
   uint4_t VRegB_12x() const {
     return VRegB_12x(Fetch16(0));
   }
   uint16_t VRegB_21c() const;
   uint16_t VRegB_21h() const;
   int16_t VRegB_21s() const;
   int16_t VRegB_21t() const;
   uint8_t VRegB_22b() const;
   uint4_t VRegB_22c() const {
     return VRegB_22c(Fetch16(0));
   }
   uint4_t VRegB_22s() const {
     return VRegB_22s(Fetch16(0));
   }
   uint4_t VRegB_22t() const {
     return VRegB_22t(Fetch16(0));
   }
   uint16_t VRegB_22x() const;
   uint8_t VRegB_23x() const;
   uint32_t VRegB_31c() const;
   int32_t VRegB_31i() const;
   int32_t VRegB_31t() const;
   uint16_t VRegB_32x() const;
   uint16_t VRegB_35c() const;
   uint16_t VRegB_3rc() const;
   uint64_t VRegB_51l() const;  // vB_wide

   // The following methods return the vB operand for all instruction formats where it is encoded in
   // the first 16 bits of instruction. The "inst_data" parameter holds these 16 bits. The returned
   // value is decoded from it.
   int4_t VRegB_11n(uint16_t inst_data) const;
   uint4_t VRegB_12x(uint16_t inst_data) const;
   uint4_t VRegB_22c(uint16_t inst_data) const;
   uint4_t VRegB_22s(uint16_t inst_data) const;
   uint4_t VRegB_22t(uint16_t inst_data) const;

   // VRegC
   bool HasVRegC() const;
   int32_t VRegC() const;

   int8_t VRegC_22b() const;
   uint16_t VRegC_22c() const;
   int16_t VRegC_22s() const;
   int16_t VRegC_22t() const;
   uint8_t VRegC_23x() const;
   uint4_t VRegC_35c() const;
   uint16_t VRegC_3rc() const;

   // Fills the given array with the 'arg' array of the instruction.
   bool HasVarArgs() const;
   void GetVarArgs(uint32_t args[kMaxVarArgRegs], uint16_t inst_data) const;
   void GetVarArgs(uint32_t args[kMaxVarArgRegs]) const {
     return GetVarArgs(args, Fetch16(0));
   }

   // Returns the opcode field of the instruction. The given "inst_data" parameter must be the first
   // 16 bits of instruction.
   Code Opcode(uint16_t inst_data) const {
     DCHECK_EQ(inst_data, Fetch16(0));
     return static_cast<Code>(inst_data & 0xFF);
   }

   // Returns the opcode field of the instruction from the first 16 bits of instruction.
   Code Opcode() const {
     return Opcode(Fetch16(0));
   }

   void SetOpcode(Code opcode) {
     DCHECK_LT(static_cast<uint16_t>(opcode), 256u);
     uint16_t* insns = reinterpret_cast<uint16_t*>(this);
     insns[0] = (insns[0] & 0xff00) | static_cast<uint16_t>(opcode);
   }

   void SetVRegA_10x(uint8_t val) {
     DCHECK(FormatOf(Opcode()) == k10x);
     uint16_t* insns = reinterpret_cast<uint16_t*>(this);
     insns[0] = (val << 8) | (insns[0] & 0x00ff);
   }

   void SetVRegB_3rc(uint16_t val) {
     DCHECK(FormatOf(Opcode()) == k3rc);
     uint16_t* insns = reinterpret_cast<uint16_t*>(this);
     insns[1] = val;
   }

   void SetVRegB_35c(uint16_t val) {
     DCHECK(FormatOf(Opcode()) == k35c);
     uint16_t* insns = reinterpret_cast<uint16_t*>(this);
     insns[1] = val;
   }

   void SetVRegC_22c(uint16_t val) {
     DCHECK(FormatOf(Opcode()) == k22c);
     uint16_t* insns = reinterpret_cast<uint16_t*>(this);
     insns[1] = val;
   }

   // Returns the format of the given opcode.
   static Format FormatOf(Code opcode) {
     return kInstructionFormats[opcode];
   }

   // Returns the flags for the given opcode.
   static int FlagsOf(Code opcode) {
     return kInstructionFlags[opcode];
   }

   // Return the verify flags for the given opcode.
   static int VerifyFlagsOf(Code opcode) {
     return kInstructionVerifyFlags[opcode];
   }

   // Returns true if this instruction is a branch.
   bool IsBranch() const {
     return (kInstructionFlags[Opcode()] & kBranch) != 0;
   }

   // Returns true if this instruction is a unconditional branch.
   bool IsUnconditional() const {
     return (kInstructionFlags[Opcode()] & kUnconditional) != 0;
   }

   // Returns the branch offset if this instruction is a branch.
   int32_t GetTargetOffset() const;

   // Returns true if the instruction allows control flow to go to the following instruction.
   bool CanFlowThrough() const;

   // Returns true if this instruction is a switch.
   bool IsSwitch() const {
     return (kInstructionFlags[Opcode()] & kSwitch) != 0;
   }

   // Returns true if this instruction can throw.
   bool IsThrow() const {
     return (kInstructionFlags[Opcode()] & kThrow) != 0;
   }

   // Determine if the instruction is any of 'return' instructions.
   bool IsReturn() const {
     return (kInstructionFlags[Opcode()] & kReturn) != 0;
   }

   // Determine if this instruction ends execution of its basic block.
   bool IsBasicBlockEnd() const {
     return IsBranch() || IsReturn() || Opcode() == THROW;
   }

   // Determine if this instruction is an invoke.
   bool IsInvoke() const {
     return (kInstructionFlags[Opcode()] & kInvoke) != 0;
   }

   int GetVerifyTypeArgumentA() const {
     return (kInstructionVerifyFlags[Opcode()] & (kVerifyRegA | kVerifyRegAWide));
   }

   int GetVerifyTypeArgumentB() const {
     return (kInstructionVerifyFlags[Opcode()] & (kVerifyRegB | kVerifyRegBField |
         kVerifyRegBMethod | kVerifyRegBNewInstance | kVerifyRegBString | kVerifyRegBType |
         kVerifyRegBWide));
   }

   int GetVerifyTypeArgumentC() const {
     return (kInstructionVerifyFlags[Opcode()] & (kVerifyRegC | kVerifyRegCField |
         kVerifyRegCNewArray | kVerifyRegCType | kVerifyRegCWide));
   }

   int GetVerifyExtraFlags() const {
     return (kInstructionVerifyFlags[Opcode()] & (kVerifyArrayData | kVerifyBranchTarget |
         kVerifySwitchTargets | kVerifyVarArg | kVerifyVarArgRange | kVerifyError));
   }

   bool GetVerifyIsRuntimeOnly() const {
     return (kInstructionVerifyFlags[Opcode()] & kVerifyRuntimeOnly) != 0;
   }

   // Get the dex PC of this instruction as a offset in code units from the beginning of insns.
   uint32_t GetDexPc(const uint16_t* insns) const {
     return (reinterpret_cast<const uint16_t*>(this) - insns);
   }

   // Dump decoded version of instruction
   std::string DumpString(const DexFile*) const;

   // Dump code_units worth of this instruction, padding to code_units for shorter instructions
   std::string DumpHex(size_t code_units) const;

   uint16_t Fetch16(size_t offset) const {
     const uint16_t* insns = reinterpret_cast<const uint16_t*>(this);
     return insns[offset];
   }

  private:
   size_t SizeInCodeUnitsComplexOpcode() const;

   uint32_t Fetch32(size_t offset) const {
     return (Fetch16(offset) | ((uint32_t) Fetch16(offset + 1) << 16));
   }

   uint4_t InstA() const {
     return InstA(Fetch16(0));
   }

   uint4_t InstB() const {
     return InstB(Fetch16(0));
   }

   uint8_t InstAA() const {
     return InstAA(Fetch16(0));
   }

   uint4_t InstA(uint16_t inst_data) const {
     DCHECK_EQ(inst_data, Fetch16(0));
     return static_cast<uint4_t>((inst_data >> 8) & 0x0f);
   }

   uint4_t InstB(uint16_t inst_data) const {
     DCHECK_EQ(inst_data, Fetch16(0));
     return static_cast<uint4_t>(inst_data >> 12);
   }

   uint8_t InstAA(uint16_t inst_data) const {
     DCHECK_EQ(inst_data, Fetch16(0));
     return static_cast<uint8_t>(inst_data >> 8);
   }

   static const char* const kInstructionNames[];
   static Format const kInstructionFormats[];
   static int const kInstructionFlags[];
   static int const kInstructionVerifyFlags[];
   static int const kInstructionSizeInCodeUnits[];
   DISALLOW_IMPLICIT_CONSTRUCTORS(Instruction);
 };
 std::ostream& operator<<(std::ostream& os, const Instruction::Code& code);
 std::ostream& operator<<(std::ostream& os, const Instruction::Format& format);
 std::ostream& operator<<(std::ostream& os, const Instruction::Flags& flags);
 std::ostream& operator<<(std::ostream& os, const Instruction::VerifyFlag& vflags);

 }  // namespace art

 #endif  // ART_RUNTIME_DEX_INSTRUCTION_H_
	/*
	* 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_RUNTIME_DEX_INSTRUCTION_H_
	#define ART_RUNTIME_DEX_INSTRUCTION_H_

	#include "base/logging.h"
	#include "base/macros.h"
	#include "globals.h"

	typedef uint8_t uint4_t;
	typedef int8_t int4_t;

	namespace art {

	class DexFile;

	enum {
	kNumPackedOpcodes = 0x100
	};

	class Instruction {
	public:
	// NOP-encoded switch-statement signatures.
	enum {
	kPackedSwitchSignature = 0x0100,
	kSparseSwitchSignature = 0x0200,
	kArrayDataSignature = 0x0300,
	};

	struct PACKED(4) PackedSwitchPayload {
	const uint16_t ident;
	const uint16_t case_count;
	const int32_t first_key;
	const int32_t targets[];

	private:
	DISALLOW_COPY_AND_ASSIGN(PackedSwitchPayload);
	};

	struct PACKED(4) SparseSwitchPayload {
	const uint16_t ident;
	const uint16_t case_count;
	const int32_t keys_and_targets[];

	public:
	const int32_t* GetKeys() const {
	return keys_and_targets;
	}

	const int32_t* GetTargets() const {
	return keys_and_targets + case_count;
	}

	private:
	DISALLOW_COPY_AND_ASSIGN(SparseSwitchPayload);
	};

	struct PACKED(4) ArrayDataPayload {
	const uint16_t ident;
	const uint16_t element_width;
	const uint32_t element_count;
	const uint8_t data[];

	private:
	DISALLOW_COPY_AND_ASSIGN(ArrayDataPayload);
	};

	// TODO: the code layout below is deliberate to avoid this enum being picked up by
	// generate-operator-out.py.
	enum Code
	{ // NOLINT(whitespace/braces)
	#define INSTRUCTION_ENUM(opcode, cname, p, f, r, i, a, v) cname = opcode,
	#include "dex_instruction_list.h"
	DEX_INSTRUCTION_LIST(INSTRUCTION_ENUM)
	#undef DEX_INSTRUCTION_LIST
	#undef INSTRUCTION_ENUM
	};

	enum Format {
	k10x, // op
	k12x, // op vA, vB
	k11n, // op vA, #+B
	k11x, // op vAA
	k10t, // op +AA
	k20t, // op +AAAA
	k22x, // op vAA, vBBBB
	k21t, // op vAA, +BBBB
	k21s, // op vAA, #+BBBB
	k21h, // op vAA, #+BBBB00000[00000000]
	k21c, // op vAA, thing@BBBB
	k23x, // op vAA, vBB, vCC
	k22b, // op vAA, vBB, #+CC
	k22t, // op vA, vB, +CCCC
	k22s, // op vA, vB, #+CCCC
	k22c, // op vA, vB, thing@CCCC
	k32x, // op vAAAA, vBBBB
	k30t, // op +AAAAAAAA
	k31t, // op vAA, +BBBBBBBB
	k31i, // op vAA, #+BBBBBBBB
	k31c, // op vAA, thing@BBBBBBBB
	k35c, // op {vC, vD, vE, vF, vG}, thing@BBBB (B: count, A: vG)
	k3rc, // op {vCCCC .. v(CCCC+AA-1)}, meth@BBBB
	k51l, // op vAA, #+BBBBBBBBBBBBBBBB
	};

	enum Flags {
	kBranch = 0x000001, // conditional or unconditional branch
	kContinue = 0x000002, // flow can continue to next statement
	kSwitch = 0x000004, // switch statement
	kThrow = 0x000008, // could cause an exception to be thrown
	kReturn = 0x000010, // returns, no additional statements
	kInvoke = 0x000020, // a flavor of invoke
	kUnconditional = 0x000040, // unconditional branch
	kAdd = 0x000080, // addition
	kSubtract = 0x000100, // subtract
	kMultiply = 0x000200, // multiply
	kDivide = 0x000400, // division
	kRemainder = 0x000800, // remainder
	kAnd = 0x001000, // and
	kOr = 0x002000, // or
	kXor = 0x004000, // xor
	kShl = 0x008000, // shl
	kShr = 0x010000, // shr
	kUshr = 0x020000, // ushr
	kCast = 0x040000, // cast
	kStore = 0x080000, // store opcode
	kLoad = 0x100000, // load opcode
	kClobber = 0x200000, // clobbers memory in a big way (not just a write)
	kRegCFieldOrConstant = 0x400000, // is the third virtual register a field or literal constant (vC)
	kRegBFieldOrConstant = 0x800000, // is the second virtual register a field or literal constant (vB)
	};

	enum VerifyFlag {
	kVerifyNone = 0x000000,
	kVerifyRegA = 0x000001,
	kVerifyRegAWide = 0x000002,
	kVerifyRegB = 0x000004,
	kVerifyRegBField = 0x000008,
	kVerifyRegBMethod = 0x000010,
	kVerifyRegBNewInstance = 0x000020,
	kVerifyRegBString = 0x000040,
	kVerifyRegBType = 0x000080,
	kVerifyRegBWide = 0x000100,
	kVerifyRegC = 0x000200,
	kVerifyRegCField = 0x000400,
	kVerifyRegCNewArray = 0x000800,
	kVerifyRegCType = 0x001000,
	kVerifyRegCWide = 0x002000,
	kVerifyArrayData = 0x004000,
	kVerifyBranchTarget = 0x008000,
	kVerifySwitchTargets = 0x010000,
	kVerifyVarArg = 0x020000,
	kVerifyVarArgRange = 0x040000,
	kVerifyRuntimeOnly = 0x080000,
	kVerifyError = 0x100000,
	};

	static constexpr uint32_t kMaxVarArgRegs = 5;

	// Returns the size (in 2 byte code units) of this instruction.
	size_t SizeInCodeUnits() const {
	int result = kInstructionSizeInCodeUnits[Opcode()];
	if (UNLIKELY(result < 0)) {
	return SizeInCodeUnitsComplexOpcode();
	} else {
	return static_cast<size_t>(result);
	}
	}

	// Reads an instruction out of the stream at the specified address.
	static const Instruction* At(const uint16_t* code) {
	DCHECK(code != NULL);
	return reinterpret_cast<const Instruction*>(code);
	}

	// Reads an instruction out of the stream from the current address plus an offset.
	const Instruction* RelativeAt(int32_t offset) const {
	return At(reinterpret_cast<const uint16_t*>(this) + offset);
	}

	// Returns a pointer to the next instruction in the stream.
	const Instruction* Next() const {
	return RelativeAt(SizeInCodeUnits());
	}

	// Returns a pointer to the instruction after this 1xx instruction in the stream.
	const Instruction* Next_1xx() const {
	DCHECK(FormatOf(Opcode()) >= k10x && FormatOf(Opcode()) <= k10t);
	return RelativeAt(1);
	}

	// Returns a pointer to the instruction after this 2xx instruction in the stream.
	const Instruction* Next_2xx() const {
	DCHECK(FormatOf(Opcode()) >= k20t && FormatOf(Opcode()) <= k22c);
	return RelativeAt(2);
	}

	// Returns a pointer to the instruction after this 3xx instruction in the stream.
	const Instruction* Next_3xx() const {
	DCHECK(FormatOf(Opcode()) >= k32x && FormatOf(Opcode()) <= k3rc);
	return RelativeAt(3);
	}

	// Returns a pointer to the instruction after this 51l instruction in the stream.
	const Instruction* Next_51l() const {
	DCHECK(FormatOf(Opcode()) == k51l);
	return RelativeAt(5);
	}

	// Returns the name of this instruction's opcode.
	const char* Name() const {
	return Instruction::Name(Opcode());
	}

	// Returns the name of the given opcode.
	static const char* Name(Code opcode) {
	return kInstructionNames[opcode];
	}

	// VRegA
	bool HasVRegA() const;
	int32_t VRegA() const;

	int8_t VRegA_10t() const {
	return VRegA_10t(Fetch16(0));
	}
	uint8_t VRegA_10x() const {
	return VRegA_10x(Fetch16(0));
	}
	uint4_t VRegA_11n() const {
	return VRegA_11n(Fetch16(0));
	}
	uint8_t VRegA_11x() const {
	return VRegA_11x(Fetch16(0));
	}
	uint4_t VRegA_12x() const {
	return VRegA_12x(Fetch16(0));
	}
	int16_t VRegA_20t() const;
	uint8_t VRegA_21c() const {
	return VRegA_21c(Fetch16(0));
	}
	uint8_t VRegA_21h() const {
	return VRegA_21h(Fetch16(0));
	}
	uint8_t VRegA_21s() const {
	return VRegA_21s(Fetch16(0));
	}
	uint8_t VRegA_21t() const {
	return VRegA_21t(Fetch16(0));
	}
	uint8_t VRegA_22b() const {
	return VRegA_22b(Fetch16(0));
	}
	uint4_t VRegA_22c() const {
	return VRegA_22c(Fetch16(0));
	}
	uint4_t VRegA_22s() const {
	return VRegA_22s(Fetch16(0));
	}
	uint4_t VRegA_22t() const {
	return VRegA_22t(Fetch16(0));
	}
	uint8_t VRegA_22x() const {
	return VRegA_22x(Fetch16(0));
	}
	uint8_t VRegA_23x() const {
	return VRegA_23x(Fetch16(0));
	}
	int32_t VRegA_30t() const;
	uint8_t VRegA_31c() const {
	return VRegA_31c(Fetch16(0));
	}
	uint8_t VRegA_31i() const {
	return VRegA_31i(Fetch16(0));
	}
	uint8_t VRegA_31t() const {
	return VRegA_31t(Fetch16(0));
	}
	uint16_t VRegA_32x() const;
	uint4_t VRegA_35c() const {
	return VRegA_35c(Fetch16(0));
	}
	uint8_t VRegA_3rc() const {
	return VRegA_3rc(Fetch16(0));
	}
	uint8_t VRegA_51l() const {
	return VRegA_51l(Fetch16(0));
	}

	// The following methods return the vA operand for various instruction formats. The "inst_data"
	// parameter holds the first 16 bits of instruction which the returned value is decoded from.
	int8_t VRegA_10t(uint16_t inst_data) const;
	uint8_t VRegA_10x(uint16_t inst_data) const;
	uint4_t VRegA_11n(uint16_t inst_data) const;
	uint8_t VRegA_11x(uint16_t inst_data) const;
	uint4_t VRegA_12x(uint16_t inst_data) const;
	uint8_t VRegA_21c(uint16_t inst_data) const;
	uint8_t VRegA_21h(uint16_t inst_data) const;
	uint8_t VRegA_21s(uint16_t inst_data) const;
	uint8_t VRegA_21t(uint16_t inst_data) const;
	uint8_t VRegA_22b(uint16_t inst_data) const;
	uint4_t VRegA_22c(uint16_t inst_data) const;
	uint4_t VRegA_22s(uint16_t inst_data) const;
	uint4_t VRegA_22t(uint16_t inst_data) const;
	uint8_t VRegA_22x(uint16_t inst_data) const;
	uint8_t VRegA_23x(uint16_t inst_data) const;
	uint8_t VRegA_31c(uint16_t inst_data) const;
	uint8_t VRegA_31i(uint16_t inst_data) const;
	uint8_t VRegA_31t(uint16_t inst_data) const;
	uint4_t VRegA_35c(uint16_t inst_data) const;
	uint8_t VRegA_3rc(uint16_t inst_data) const;
	uint8_t VRegA_51l(uint16_t inst_data) const;

	// VRegB
	bool HasVRegB() const;
	int32_t VRegB() const;

	bool HasWideVRegB() const;
	uint64_t WideVRegB() const;

	int4_t VRegB_11n() const {
	return VRegB_11n(Fetch16(0));
	}
	uint4_t VRegB_12x() const {
	return VRegB_12x(Fetch16(0));
	}
	uint16_t VRegB_21c() const;
	uint16_t VRegB_21h() const;
	int16_t VRegB_21s() const;
	int16_t VRegB_21t() const;
	uint8_t VRegB_22b() const;
	uint4_t VRegB_22c() const {
	return VRegB_22c(Fetch16(0));
	}
	uint4_t VRegB_22s() const {
	return VRegB_22s(Fetch16(0));
	}
	uint4_t VRegB_22t() const {
	return VRegB_22t(Fetch16(0));
	}
	uint16_t VRegB_22x() const;
	uint8_t VRegB_23x() const;
	uint32_t VRegB_31c() const;
	int32_t VRegB_31i() const;
	int32_t VRegB_31t() const;
	uint16_t VRegB_32x() const;
	uint16_t VRegB_35c() const;
	uint16_t VRegB_3rc() const;
	uint64_t VRegB_51l() const; // vB_wide

	// The following methods return the vB operand for all instruction formats where it is encoded in
	// the first 16 bits of instruction. The "inst_data" parameter holds these 16 bits. The returned
	// value is decoded from it.
	int4_t VRegB_11n(uint16_t inst_data) const;
	uint4_t VRegB_12x(uint16_t inst_data) const;
	uint4_t VRegB_22c(uint16_t inst_data) const;
	uint4_t VRegB_22s(uint16_t inst_data) const;
	uint4_t VRegB_22t(uint16_t inst_data) const;

	// VRegC
	bool HasVRegC() const;
	int32_t VRegC() const;

	int8_t VRegC_22b() const;
	uint16_t VRegC_22c() const;
	int16_t VRegC_22s() const;
	int16_t VRegC_22t() const;
	uint8_t VRegC_23x() const;
	uint4_t VRegC_35c() const;
	uint16_t VRegC_3rc() const;

	// Fills the given array with the 'arg' array of the instruction.
	bool HasVarArgs() const;
	void GetVarArgs(uint32_t args[kMaxVarArgRegs], uint16_t inst_data) const;
	void GetVarArgs(uint32_t args[kMaxVarArgRegs]) const {
	return GetVarArgs(args, Fetch16(0));
	}

	// Returns the opcode field of the instruction. The given "inst_data" parameter must be the first
	// 16 bits of instruction.
	Code Opcode(uint16_t inst_data) const {
	DCHECK_EQ(inst_data, Fetch16(0));
	return static_cast<Code>(inst_data & 0xFF);
	}

	// Returns the opcode field of the instruction from the first 16 bits of instruction.
	Code Opcode() const {
	return Opcode(Fetch16(0));
	}

	void SetOpcode(Code opcode) {
	DCHECK_LT(static_cast<uint16_t>(opcode), 256u);
	uint16_t* insns = reinterpret_cast<uint16_t*>(this);
	insns[0] = (insns[0] & 0xff00) \| static_cast<uint16_t>(opcode);
	}

	void SetVRegA_10x(uint8_t val) {
	DCHECK(FormatOf(Opcode()) == k10x);
	uint16_t* insns = reinterpret_cast<uint16_t*>(this);
	insns[0] = (val << 8) \| (insns[0] & 0x00ff);
	}

	void SetVRegB_3rc(uint16_t val) {
	DCHECK(FormatOf(Opcode()) == k3rc);
	uint16_t* insns = reinterpret_cast<uint16_t*>(this);
	insns[1] = val;
	}

	void SetVRegB_35c(uint16_t val) {
	DCHECK(FormatOf(Opcode()) == k35c);
	uint16_t* insns = reinterpret_cast<uint16_t*>(this);
	insns[1] = val;
	}

	void SetVRegC_22c(uint16_t val) {
	DCHECK(FormatOf(Opcode()) == k22c);
	uint16_t* insns = reinterpret_cast<uint16_t*>(this);
	insns[1] = val;
	}

	// Returns the format of the given opcode.
	static Format FormatOf(Code opcode) {
	return kInstructionFormats[opcode];
	}

	// Returns the flags for the given opcode.
	static int FlagsOf(Code opcode) {
	return kInstructionFlags[opcode];
	}

	// Return the verify flags for the given opcode.
	static int VerifyFlagsOf(Code opcode) {
	return kInstructionVerifyFlags[opcode];
	}

	// Returns true if this instruction is a branch.
	bool IsBranch() const {
	return (kInstructionFlags[Opcode()] & kBranch) != 0;
	}

	// Returns true if this instruction is a unconditional branch.
	bool IsUnconditional() const {
	return (kInstructionFlags[Opcode()] & kUnconditional) != 0;
	}

	// Returns the branch offset if this instruction is a branch.
	int32_t GetTargetOffset() const;

	// Returns true if the instruction allows control flow to go to the following instruction.
	bool CanFlowThrough() const;

	// Returns true if this instruction is a switch.
	bool IsSwitch() const {
	return (kInstructionFlags[Opcode()] & kSwitch) != 0;
	}

	// Returns true if this instruction can throw.
	bool IsThrow() const {
	return (kInstructionFlags[Opcode()] & kThrow) != 0;
	}

	// Determine if the instruction is any of 'return' instructions.
	bool IsReturn() const {
	return (kInstructionFlags[Opcode()] & kReturn) != 0;
	}

	// Determine if this instruction ends execution of its basic block.
	bool IsBasicBlockEnd() const {
	return IsBranch() \|\| IsReturn() \|\| Opcode() == THROW;
	}

	// Determine if this instruction is an invoke.
	bool IsInvoke() const {
	return (kInstructionFlags[Opcode()] & kInvoke) != 0;
	}

	int GetVerifyTypeArgumentA() const {
	return (kInstructionVerifyFlags[Opcode()] & (kVerifyRegA \| kVerifyRegAWide));
	}

	int GetVerifyTypeArgumentB() const {
	return (kInstructionVerifyFlags[Opcode()] & (kVerifyRegB \| kVerifyRegBField \|
	kVerifyRegBMethod \| kVerifyRegBNewInstance \| kVerifyRegBString \| kVerifyRegBType \|
	kVerifyRegBWide));
	}

	int GetVerifyTypeArgumentC() const {
	return (kInstructionVerifyFlags[Opcode()] & (kVerifyRegC \| kVerifyRegCField \|
	kVerifyRegCNewArray \| kVerifyRegCType \| kVerifyRegCWide));
	}

	int GetVerifyExtraFlags() const {
	return (kInstructionVerifyFlags[Opcode()] & (kVerifyArrayData \| kVerifyBranchTarget \|
	kVerifySwitchTargets \| kVerifyVarArg \| kVerifyVarArgRange \| kVerifyError));
	}

	bool GetVerifyIsRuntimeOnly() const {
	return (kInstructionVerifyFlags[Opcode()] & kVerifyRuntimeOnly) != 0;
	}

	// Get the dex PC of this instruction as a offset in code units from the beginning of insns.
	uint32_t GetDexPc(const uint16_t* insns) const {
	return (reinterpret_cast<const uint16_t*>(this) - insns);
	}

	// Dump decoded version of instruction
	std::string DumpString(const DexFile*) const;

	// Dump code_units worth of this instruction, padding to code_units for shorter instructions
	std::string DumpHex(size_t code_units) const;

	uint16_t Fetch16(size_t offset) const {
	const uint16_t* insns = reinterpret_cast<const uint16_t*>(this);
	return insns[offset];
	}

	private:
	size_t SizeInCodeUnitsComplexOpcode() const;

	uint32_t Fetch32(size_t offset) const {
	return (Fetch16(offset) \| ((uint32_t) Fetch16(offset + 1) << 16));
	}

	uint4_t InstA() const {
	return InstA(Fetch16(0));
	}

	uint4_t InstB() const {
	return InstB(Fetch16(0));
	}

	uint8_t InstAA() const {
	return InstAA(Fetch16(0));
	}

	uint4_t InstA(uint16_t inst_data) const {
	DCHECK_EQ(inst_data, Fetch16(0));
	return static_cast<uint4_t>((inst_data >> 8) & 0x0f);
	}

	uint4_t InstB(uint16_t inst_data) const {
	DCHECK_EQ(inst_data, Fetch16(0));
	return static_cast<uint4_t>(inst_data >> 12);
	}

	uint8_t InstAA(uint16_t inst_data) const {
	DCHECK_EQ(inst_data, Fetch16(0));
	return static_cast<uint8_t>(inst_data >> 8);
	}

	static const char* const kInstructionNames[];
	static Format const kInstructionFormats[];
	static int const kInstructionFlags[];
	static int const kInstructionVerifyFlags[];
	static int const kInstructionSizeInCodeUnits[];
	DISALLOW_IMPLICIT_CONSTRUCTORS(Instruction);
	};
	std::ostream& operator<<(std::ostream& os, const Instruction::Code& code);
	std::ostream& operator<<(std::ostream& os, const Instruction::Format& format);
	std::ostream& operator<<(std::ostream& os, const Instruction::Flags& flags);
	std::ostream& operator<<(std::ostream& os, const Instruction::VerifyFlag& vflags);

	} // namespace art

	#endif // ART_RUNTIME_DEX_INSTRUCTION_H_