X86DisassemblerDecoder.h

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//===-- X86DisassemblerDecoderInternal.h - Disassembler decoder -*- 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 X86 Disassembler.
// It contains the public interface of the instruction decoder.
// Documentation for the disassembler can be found in X86Disassembler.h.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TARGET_X86_DISASSEMBLER_X86DISASSEMBLERDECODER_H
#define LLVM_LIB_TARGET_X86_DISASSEMBLER_X86DISASSEMBLERDECODER_H

#include "X86DisassemblerDecoderCommon.h"
#include "llvm/ADT/ArrayRef.h"

namespace llvm {
namespace X86Disassembler {

// Accessor functions for various fields of an Intel instruction
#define modFromModRM(modRM)  (((modRM) & 0xc0) >> 6)
#define regFromModRM(modRM)  (((modRM) & 0x38) >> 3)
#define rmFromModRM(modRM)   ((modRM) & 0x7)
#define scaleFromSIB(sib)    (((sib) & 0xc0) >> 6)
#define indexFromSIB(sib)    (((sib) & 0x38) >> 3)
#define baseFromSIB(sib)     ((sib) & 0x7)
#define wFromREX(rex)        (((rex) & 0x8) >> 3)
#define rFromREX(rex)        (((rex) & 0x4) >> 2)
#define xFromREX(rex)        (((rex) & 0x2) >> 1)
#define bFromREX(rex)        ((rex) & 0x1)

#define rFromEVEX2of4(evex)     (((~(evex)) & 0x80) >> 7)
#define xFromEVEX2of4(evex)     (((~(evex)) & 0x40) >> 6)
#define bFromEVEX2of4(evex)     (((~(evex)) & 0x20) >> 5)
#define r2FromEVEX2of4(evex)    (((~(evex)) & 0x10) >> 4)
#define mmFromEVEX2of4(evex)    ((evex) & 0x3)
#define wFromEVEX3of4(evex)     (((evex) & 0x80) >> 7)
#define vvvvFromEVEX3of4(evex)  (((~(evex)) & 0x78) >> 3)
#define ppFromEVEX3of4(evex)    ((evex) & 0x3)
#define zFromEVEX4of4(evex)     (((evex) & 0x80) >> 7)
#define l2FromEVEX4of4(evex)    (((evex) & 0x40) >> 6)
#define lFromEVEX4of4(evex)     (((evex) & 0x20) >> 5)
#define bFromEVEX4of4(evex)     (((evex) & 0x10) >> 4)
#define v2FromEVEX4of4(evex)    (((~evex) & 0x8) >> 3)
#define aaaFromEVEX4of4(evex)   ((evex) & 0x7)

#define rFromVEX2of3(vex)       (((~(vex)) & 0x80) >> 7)
#define xFromVEX2of3(vex)       (((~(vex)) & 0x40) >> 6)
#define bFromVEX2of3(vex)       (((~(vex)) & 0x20) >> 5)
#define mmmmmFromVEX2of3(vex)   ((vex) & 0x1f)
#define wFromVEX3of3(vex)       (((vex) & 0x80) >> 7)
#define vvvvFromVEX3of3(vex)    (((~(vex)) & 0x78) >> 3)
#define lFromVEX3of3(vex)       (((vex) & 0x4) >> 2)
#define ppFromVEX3of3(vex)      ((vex) & 0x3)

#define rFromVEX2of2(vex)       (((~(vex)) & 0x80) >> 7)
#define vvvvFromVEX2of2(vex)    (((~(vex)) & 0x78) >> 3)
#define lFromVEX2of2(vex)       (((vex) & 0x4) >> 2)
#define ppFromVEX2of2(vex)      ((vex) & 0x3)

#define rFromXOP2of3(xop)       (((~(xop)) & 0x80) >> 7)
#define xFromXOP2of3(xop)       (((~(xop)) & 0x40) >> 6)
#define bFromXOP2of3(xop)       (((~(xop)) & 0x20) >> 5)
#define mmmmmFromXOP2of3(xop)   ((xop) & 0x1f)
#define wFromXOP3of3(xop)       (((xop) & 0x80) >> 7)
#define vvvvFromXOP3of3(vex)    (((~(vex)) & 0x78) >> 3)
#define lFromXOP3of3(xop)       (((xop) & 0x4) >> 2)
#define ppFromXOP3of3(xop)      ((xop) & 0x3)

// These enums represent Intel registers for use by the decoder.
#define REGS_8BIT     \
  ENTRY(AL)           \
  ENTRY(CL)           \
  ENTRY(DL)           \
  ENTRY(BL)           \
  ENTRY(AH)           \
  ENTRY(CH)           \
  ENTRY(DH)           \
  ENTRY(BH)           \
  ENTRY(R8B)          \
  ENTRY(R9B)          \
  ENTRY(R10B)         \
  ENTRY(R11B)         \
  ENTRY(R12B)         \
  ENTRY(R13B)         \
  ENTRY(R14B)         \
  ENTRY(R15B)         \
  ENTRY(SPL)          \
  ENTRY(BPL)          \
  ENTRY(SIL)          \
  ENTRY(DIL)

#define EA_BASES_16BIT  \
  ENTRY(BX_SI)          \
  ENTRY(BX_DI)          \
  ENTRY(BP_SI)          \
  ENTRY(BP_DI)          \
  ENTRY(SI)             \
  ENTRY(DI)             \
  ENTRY(BP)             \
  ENTRY(BX)             \
  ENTRY(R8W)            \
  ENTRY(R9W)            \
  ENTRY(R10W)           \
  ENTRY(R11W)           \
  ENTRY(R12W)           \
  ENTRY(R13W)           \
  ENTRY(R14W)           \
  ENTRY(R15W)

#define REGS_16BIT    \
  ENTRY(AX)           \
  ENTRY(CX)           \
  ENTRY(DX)           \
  ENTRY(BX)           \
  ENTRY(SP)           \
  ENTRY(BP)           \
  ENTRY(SI)           \
  ENTRY(DI)           \
  ENTRY(R8W)          \
  ENTRY(R9W)          \
  ENTRY(R10W)         \
  ENTRY(R11W)         \
  ENTRY(R12W)         \
  ENTRY(R13W)         \
  ENTRY(R14W)         \
  ENTRY(R15W)

#define EA_BASES_32BIT  \
  ENTRY(EAX)            \
  ENTRY(ECX)            \
  ENTRY(EDX)            \
  ENTRY(EBX)            \
  ENTRY(sib)            \
  ENTRY(EBP)            \
  ENTRY(ESI)            \
  ENTRY(EDI)            \
  ENTRY(R8D)            \
  ENTRY(R9D)            \
  ENTRY(R10D)           \
  ENTRY(R11D)           \
  ENTRY(R12D)           \
  ENTRY(R13D)           \
  ENTRY(R14D)           \
  ENTRY(R15D)

#define REGS_32BIT  \
  ENTRY(EAX)        \
  ENTRY(ECX)        \
  ENTRY(EDX)        \
  ENTRY(EBX)        \
  ENTRY(ESP)        \
  ENTRY(EBP)        \
  ENTRY(ESI)        \
  ENTRY(EDI)        \
  ENTRY(R8D)        \
  ENTRY(R9D)        \
  ENTRY(R10D)       \
  ENTRY(R11D)       \
  ENTRY(R12D)       \
  ENTRY(R13D)       \
  ENTRY(R14D)       \
  ENTRY(R15D)

#define EA_BASES_64BIT  \
  ENTRY(RAX)            \
  ENTRY(RCX)            \
  ENTRY(RDX)            \
  ENTRY(RBX)            \
  ENTRY(sib64)          \
  ENTRY(RBP)            \
  ENTRY(RSI)            \
  ENTRY(RDI)            \
  ENTRY(R8)             \
  ENTRY(R9)             \
  ENTRY(R10)            \
  ENTRY(R11)            \
  ENTRY(R12)            \
  ENTRY(R13)            \
  ENTRY(R14)            \
  ENTRY(R15)

#define REGS_64BIT  \
  ENTRY(RAX)        \
  ENTRY(RCX)        \
  ENTRY(RDX)        \
  ENTRY(RBX)        \
  ENTRY(RSP)        \
  ENTRY(RBP)        \
  ENTRY(RSI)        \
  ENTRY(RDI)        \
  ENTRY(R8)         \
  ENTRY(R9)         \
  ENTRY(R10)        \
  ENTRY(R11)        \
  ENTRY(R12)        \
  ENTRY(R13)        \
  ENTRY(R14)        \
  ENTRY(R15)

#define REGS_MMX  \
  ENTRY(MM0)      \
  ENTRY(MM1)      \
  ENTRY(MM2)      \
  ENTRY(MM3)      \
  ENTRY(MM4)      \
  ENTRY(MM5)      \
  ENTRY(MM6)      \
  ENTRY(MM7)

#define REGS_XMM  \
  ENTRY(XMM0)     \
  ENTRY(XMM1)     \
  ENTRY(XMM2)     \
  ENTRY(XMM3)     \
  ENTRY(XMM4)     \
  ENTRY(XMM5)     \
  ENTRY(XMM6)     \
  ENTRY(XMM7)     \
  ENTRY(XMM8)     \
  ENTRY(XMM9)     \
  ENTRY(XMM10)    \
  ENTRY(XMM11)    \
  ENTRY(XMM12)    \
  ENTRY(XMM13)    \
  ENTRY(XMM14)    \
  ENTRY(XMM15)    \
  ENTRY(XMM16)    \
  ENTRY(XMM17)    \
  ENTRY(XMM18)    \
  ENTRY(XMM19)    \
  ENTRY(XMM20)    \
  ENTRY(XMM21)    \
  ENTRY(XMM22)    \
  ENTRY(XMM23)    \
  ENTRY(XMM24)    \
  ENTRY(XMM25)    \
  ENTRY(XMM26)    \
  ENTRY(XMM27)    \
  ENTRY(XMM28)    \
  ENTRY(XMM29)    \
  ENTRY(XMM30)    \
  ENTRY(XMM31)

#define REGS_YMM  \
  ENTRY(YMM0)     \
  ENTRY(YMM1)     \
  ENTRY(YMM2)     \
  ENTRY(YMM3)     \
  ENTRY(YMM4)     \
  ENTRY(YMM5)     \
  ENTRY(YMM6)     \
  ENTRY(YMM7)     \
  ENTRY(YMM8)     \
  ENTRY(YMM9)     \
  ENTRY(YMM10)    \
  ENTRY(YMM11)    \
  ENTRY(YMM12)    \
  ENTRY(YMM13)    \
  ENTRY(YMM14)    \
  ENTRY(YMM15)    \
  ENTRY(YMM16)    \
  ENTRY(YMM17)    \
  ENTRY(YMM18)    \
  ENTRY(YMM19)    \
  ENTRY(YMM20)    \
  ENTRY(YMM21)    \
  ENTRY(YMM22)    \
  ENTRY(YMM23)    \
  ENTRY(YMM24)    \
  ENTRY(YMM25)    \
  ENTRY(YMM26)    \
  ENTRY(YMM27)    \
  ENTRY(YMM28)    \
  ENTRY(YMM29)    \
  ENTRY(YMM30)    \
  ENTRY(YMM31)

#define REGS_ZMM  \
  ENTRY(ZMM0)     \
  ENTRY(ZMM1)     \
  ENTRY(ZMM2)     \
  ENTRY(ZMM3)     \
  ENTRY(ZMM4)     \
  ENTRY(ZMM5)     \
  ENTRY(ZMM6)     \
  ENTRY(ZMM7)     \
  ENTRY(ZMM8)     \
  ENTRY(ZMM9)     \
  ENTRY(ZMM10)    \
  ENTRY(ZMM11)    \
  ENTRY(ZMM12)    \
  ENTRY(ZMM13)    \
  ENTRY(ZMM14)    \
  ENTRY(ZMM15)    \
  ENTRY(ZMM16)    \
  ENTRY(ZMM17)    \
  ENTRY(ZMM18)    \
  ENTRY(ZMM19)    \
  ENTRY(ZMM20)    \
  ENTRY(ZMM21)    \
  ENTRY(ZMM22)    \
  ENTRY(ZMM23)    \
  ENTRY(ZMM24)    \
  ENTRY(ZMM25)    \
  ENTRY(ZMM26)    \
  ENTRY(ZMM27)    \
  ENTRY(ZMM28)    \
  ENTRY(ZMM29)    \
  ENTRY(ZMM30)    \
  ENTRY(ZMM31)

#define REGS_MASKS \
  ENTRY(K0)        \
  ENTRY(K1)        \
  ENTRY(K2)        \
  ENTRY(K3)        \
  ENTRY(K4)        \
  ENTRY(K5)        \
  ENTRY(K6)        \
  ENTRY(K7)

#define REGS_SEGMENT \
  ENTRY(ES)          \
  ENTRY(CS)          \
  ENTRY(SS)          \
  ENTRY(DS)          \
  ENTRY(FS)          \
  ENTRY(GS)

#define REGS_DEBUG  \
  ENTRY(DR0)        \
  ENTRY(DR1)        \
  ENTRY(DR2)        \
  ENTRY(DR3)        \
  ENTRY(DR4)        \
  ENTRY(DR5)        \
  ENTRY(DR6)        \
  ENTRY(DR7)

#define REGS_CONTROL  \
  ENTRY(CR0)          \
  ENTRY(CR1)          \
  ENTRY(CR2)          \
  ENTRY(CR3)          \
  ENTRY(CR4)          \
  ENTRY(CR5)          \
  ENTRY(CR6)          \
  ENTRY(CR7)          \
  ENTRY(CR8)

#define ALL_EA_BASES  \
  EA_BASES_16BIT      \
  EA_BASES_32BIT      \
  EA_BASES_64BIT

#define ALL_SIB_BASES \
  REGS_32BIT          \
  REGS_64BIT

#define ALL_REGS      \
  REGS_8BIT           \
  REGS_16BIT          \
  REGS_32BIT          \
  REGS_64BIT          \
  REGS_MMX            \
  REGS_XMM            \
  REGS_YMM            \
  REGS_ZMM            \
  REGS_MASKS          \
  REGS_SEGMENT        \
  REGS_DEBUG          \
  REGS_CONTROL        \
  ENTRY(RIP)

/// \brief All possible values of the base field for effective-address
/// computations, a.k.a. the Mod and R/M fields of the ModR/M byte.
/// We distinguish between bases (EA_BASE_*) and registers that just happen
/// to be referred to when Mod == 0b11 (EA_REG_*).
enum EABase {
  EA_BASE_NONE,
#define ENTRY(x) EA_BASE_##x,
  ALL_EA_BASES
#undef ENTRY
#define ENTRY(x) EA_REG_##x,
  ALL_REGS
#undef ENTRY
  EA_max
};

/// \brief All possible values of the SIB index field.
/// borrows entries from ALL_EA_BASES with the special case that
/// sib is synonymous with NONE.
/// Vector SIB: index can be XMM or YMM.
enum SIBIndex {
  SIB_INDEX_NONE,
#define ENTRY(x) SIB_INDEX_##x,
  ALL_EA_BASES
  REGS_XMM
  REGS_YMM
  REGS_ZMM
#undef ENTRY
  SIB_INDEX_max
};

/// \brief All possible values of the SIB base field.
enum SIBBase {
  SIB_BASE_NONE,
#define ENTRY(x) SIB_BASE_##x,
  ALL_SIB_BASES
#undef ENTRY
  SIB_BASE_max
};

/// \brief Possible displacement types for effective-address computations.
typedef enum {
  EA_DISP_NONE,
  EA_DISP_8,
  EA_DISP_16,
  EA_DISP_32
} EADisplacement;

/// \brief All possible values of the reg field in the ModR/M byte.
enum Reg {
#define ENTRY(x) MODRM_REG_##x,
  ALL_REGS
#undef ENTRY
  MODRM_REG_max
};

/// \brief All possible segment overrides.
enum SegmentOverride {
  SEG_OVERRIDE_NONE,
  SEG_OVERRIDE_CS,
  SEG_OVERRIDE_SS,
  SEG_OVERRIDE_DS,
  SEG_OVERRIDE_ES,
  SEG_OVERRIDE_FS,
  SEG_OVERRIDE_GS,
  SEG_OVERRIDE_max
};

/// \brief Possible values for the VEX.m-mmmm field
enum VEXLeadingOpcodeByte {
  VEX_LOB_0F = 0x1,
  VEX_LOB_0F38 = 0x2,
  VEX_LOB_0F3A = 0x3
};

enum XOPMapSelect {
  XOP_MAP_SELECT_8 = 0x8,
  XOP_MAP_SELECT_9 = 0x9,
  XOP_MAP_SELECT_A = 0xA
};

/// \brief Possible values for the VEX.pp/EVEX.pp field
enum VEXPrefixCode {
  VEX_PREFIX_NONE = 0x0,
  VEX_PREFIX_66 = 0x1,
  VEX_PREFIX_F3 = 0x2,
  VEX_PREFIX_F2 = 0x3
};

enum VectorExtensionType {
  TYPE_NO_VEX_XOP   = 0x0,
  TYPE_VEX_2B       = 0x1,
  TYPE_VEX_3B       = 0x2,
  TYPE_EVEX         = 0x3,
  TYPE_XOP          = 0x4
};

/// \brief Type for the byte reader that the consumer must provide to
/// the decoder. Reads a single byte from the instruction's address space.
/// \param arg     A baton that the consumer can associate with any internal
///                state that it needs.
/// \param byte    A pointer to a single byte in memory that should be set to
///                contain the value at address.
/// \param address The address in the instruction's address space that should
///                be read from.
/// \return        -1 if the byte cannot be read for any reason; 0 otherwise.
typedef int (*byteReader_t)(const void *arg, uint8_t *byte, uint64_t address);

/// \brief Type for the logging function that the consumer can provide to
/// get debugging output from the decoder.
/// \param arg A baton that the consumer can associate with any internal
///            state that it needs.
/// \param log A string that contains the message.  Will be reused after
///            the logger returns.
typedef void (*dlog_t)(void *arg, const char *log);

/// The specification for how to extract and interpret a full instruction and
/// its operands.
struct InstructionSpecifier {
  uint16_t operands;
};

/// The x86 internal instruction, which is produced by the decoder.
struct InternalInstruction {
  // Reader interface (C)
  byteReader_t reader;
  // Opaque value passed to the reader
  const void* readerArg;
  // The address of the next byte to read via the reader
  uint64_t readerCursor;

  // Logger interface (C)
  dlog_t dlog;
  // Opaque value passed to the logger
  void* dlogArg;

  // General instruction information

  // The mode to disassemble for (64-bit, protected, real)
  DisassemblerMode mode;
  // The start of the instruction, usable with the reader
  uint64_t startLocation;
  // The length of the instruction, in bytes
  size_t length;

  // Prefix state

  // 1 if the prefix byte corresponding to the entry is present; 0 if not
  uint8_t prefixPresent[0x100];
  // contains the location (for use with the reader) of the prefix byte
  uint64_t prefixLocations[0x100];
  // The value of the vector extension prefix(EVEX/VEX/XOP), if present
  uint8_t vectorExtensionPrefix[4];
  // The type of the vector extension prefix
  VectorExtensionType vectorExtensionType;
  // The value of the REX prefix, if present
  uint8_t rexPrefix;
  // The location where a mandatory prefix would have to be (i.e., right before
  // the opcode, or right before the REX prefix if one is present).
  uint64_t necessaryPrefixLocation;
  // The segment override type
  SegmentOverride segmentOverride;
  // 1 if the prefix byte, 0xf2 or 0xf3 is xacquire or xrelease
  bool xAcquireRelease;

  // Sizes of various critical pieces of data, in bytes
  uint8_t registerSize;
  uint8_t addressSize;
  uint8_t displacementSize;
  uint8_t immediateSize;

  // Offsets from the start of the instruction to the pieces of data, which is
  // needed to find relocation entries for adding symbolic operands.
  uint8_t displacementOffset;
  uint8_t immediateOffset;

  // opcode state

  // The last byte of the opcode, not counting any ModR/M extension
  uint8_t opcode;
  // The ModR/M byte of the instruction, if it is an opcode extension
  uint8_t modRMExtension;

  // decode state

  // The type of opcode, used for indexing into the array of decode tables
  OpcodeType opcodeType;
  // The instruction ID, extracted from the decode table
  uint16_t instructionID;
  // The specifier for the instruction, from the instruction info table
  const InstructionSpecifier *spec;

  // state for additional bytes, consumed during operand decode.  Pattern:
  // consumed___ indicates that the byte was already consumed and does not
  // need to be consumed again.

  // The VEX.vvvv field, which contains a third register operand for some AVX
  // instructions.
  Reg                           vvvv;

  // The writemask for AVX-512 instructions which is contained in EVEX.aaa
  Reg                           writemask;

  // The ModR/M byte, which contains most register operands and some portion of
  // all memory operands.
  bool                          consumedModRM;
  uint8_t                       modRM;

  // The SIB byte, used for more complex 32- or 64-bit memory operands
  bool                          consumedSIB;
  uint8_t                       sib;

  // The displacement, used for memory operands
  bool                          consumedDisplacement;
  int32_t                       displacement;

  // Immediates.  There can be two in some cases
  uint8_t                       numImmediatesConsumed;
  uint8_t                       numImmediatesTranslated;
  uint64_t                      immediates[2];

  // A register or immediate operand encoded into the opcode
  Reg                           opcodeRegister;

  // Portions of the ModR/M byte

  // These fields determine the allowable values for the ModR/M fields, which
  // depend on operand and address widths.
  EABase                        eaBaseBase;
  EABase                        eaRegBase;
  Reg                           regBase;

  // The Mod and R/M fields can encode a base for an effective address, or a
  // register.  These are separated into two fields here.
  EABase                        eaBase;
  EADisplacement                eaDisplacement;
  // The reg field always encodes a register
  Reg                           reg;

  // SIB state
  SIBIndex                      sibIndex;
  uint8_t                       sibScale;
  SIBBase                       sibBase;

  ArrayRef<OperandSpecifier> operands;
};

/// \brief Decode one instruction and store the decoding results in
/// a buffer provided by the consumer.
/// \param insn      The buffer to store the instruction in.  Allocated by the
///                  consumer.
/// \param reader    The byteReader_t for the bytes to be read.
/// \param readerArg An argument to pass to the reader for storing context
///                  specific to the consumer.  May be NULL.
/// \param logger    The dlog_t to be used in printing status messages from the
///                  disassembler.  May be NULL.
/// \param loggerArg An argument to pass to the logger for storing context
///                  specific to the logger.  May be NULL.
/// \param startLoc  The address (in the reader's address space) of the first
///                  byte in the instruction.
/// \param mode      The mode (16-bit, 32-bit, 64-bit) to decode in.
/// \return          Nonzero if there was an error during decode, 0 otherwise.
int decodeInstruction(InternalInstruction *insn,
                      byteReader_t reader,
                      const void *readerArg,
                      dlog_t logger,
                      void *loggerArg,
                      const void *miiArg,
                      uint64_t startLoc,
                      DisassemblerMode mode);

/// \brief Print a message to debugs()
/// \param file The name of the file printing the debug message.
/// \param line The line number that printed the debug message.
/// \param s    The message to print.
void Debug(const char *file, unsigned line, const char *s);

const char *GetInstrName(unsigned Opcode, const void *mii);

} // namespace X86Disassembler
} // namespace llvm

#endif