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      1 //===- X86RecognizableInstr.h - Disassembler instruction spec ----*- C++ -*-===//
      2 //
      3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
      4 // See https://llvm.org/LICENSE.txt for license information.
      5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
      6 //
      7 //===----------------------------------------------------------------------===//
      8 //
      9 // This file is part of the X86 Disassembler Emitter.
     10 // It contains the interface of a single recognizable instruction.
     11 // Documentation for the disassembler emitter in general can be found in
     12 //  X86DisassemblerEmitter.h.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #ifndef LLVM_UTILS_TABLEGEN_X86RECOGNIZABLEINSTR_H
     17 #define LLVM_UTILS_TABLEGEN_X86RECOGNIZABLEINSTR_H
     18 
     19 #include "CodeGenTarget.h"
     20 #include "X86DisassemblerTables.h"
     21 #include "llvm/Support/DataTypes.h"
     22 #include "llvm/TableGen/Record.h"
     23 
     24 namespace llvm {
     25 
     26 #define X86_INSTR_MRM_MAPPING     \
     27   MAP(C0, 64)                     \
     28   MAP(C1, 65)                     \
     29   MAP(C2, 66)                     \
     30   MAP(C3, 67)                     \
     31   MAP(C4, 68)                     \
     32   MAP(C5, 69)                     \
     33   MAP(C6, 70)                     \
     34   MAP(C7, 71)                     \
     35   MAP(C8, 72)                     \
     36   MAP(C9, 73)                     \
     37   MAP(CA, 74)                     \
     38   MAP(CB, 75)                     \
     39   MAP(CC, 76)                     \
     40   MAP(CD, 77)                     \
     41   MAP(CE, 78)                     \
     42   MAP(CF, 79)                     \
     43   MAP(D0, 80)                     \
     44   MAP(D1, 81)                     \
     45   MAP(D2, 82)                     \
     46   MAP(D3, 83)                     \
     47   MAP(D4, 84)                     \
     48   MAP(D5, 85)                     \
     49   MAP(D6, 86)                     \
     50   MAP(D7, 87)                     \
     51   MAP(D8, 88)                     \
     52   MAP(D9, 89)                     \
     53   MAP(DA, 90)                     \
     54   MAP(DB, 91)                     \
     55   MAP(DC, 92)                     \
     56   MAP(DD, 93)                     \
     57   MAP(DE, 94)                     \
     58   MAP(DF, 95)                     \
     59   MAP(E0, 96)                     \
     60   MAP(E1, 97)                     \
     61   MAP(E2, 98)                     \
     62   MAP(E3, 99)                     \
     63   MAP(E4, 100)                    \
     64   MAP(E5, 101)                    \
     65   MAP(E6, 102)                    \
     66   MAP(E7, 103)                    \
     67   MAP(E8, 104)                    \
     68   MAP(E9, 105)                    \
     69   MAP(EA, 106)                    \
     70   MAP(EB, 107)                    \
     71   MAP(EC, 108)                    \
     72   MAP(ED, 109)                    \
     73   MAP(EE, 110)                    \
     74   MAP(EF, 111)                    \
     75   MAP(F0, 112)                    \
     76   MAP(F1, 113)                    \
     77   MAP(F2, 114)                    \
     78   MAP(F3, 115)                    \
     79   MAP(F4, 116)                    \
     80   MAP(F5, 117)                    \
     81   MAP(F6, 118)                    \
     82   MAP(F7, 119)                    \
     83   MAP(F8, 120)                    \
     84   MAP(F9, 121)                    \
     85   MAP(FA, 122)                    \
     86   MAP(FB, 123)                    \
     87   MAP(FC, 124)                    \
     88   MAP(FD, 125)                    \
     89   MAP(FE, 126)                    \
     90   MAP(FF, 127)
     91 
     92 // A clone of X86 since we can't depend on something that is generated.
     93 namespace X86Local {
     94   enum {
     95     Pseudo        = 0,
     96     RawFrm        = 1,
     97     AddRegFrm     = 2,
     98     RawFrmMemOffs = 3,
     99     RawFrmSrc     = 4,
    100     RawFrmDst     = 5,
    101     RawFrmDstSrc  = 6,
    102     RawFrmImm8    = 7,
    103     RawFrmImm16   = 8,
    104     AddCCFrm      = 9,
    105     PrefixByte    = 10,
    106     MRMr0          = 21,
    107     MRMSrcMemFSIB  = 22,
    108     MRMDestMemFSIB = 23,
    109     MRMDestMem     = 24,
    110     MRMSrcMem      = 25,
    111     MRMSrcMem4VOp3 = 26,
    112     MRMSrcMemOp4   = 27,
    113     MRMSrcMemCC    = 28,
    114     MRMXmCC = 30, MRMXm = 31,
    115     MRM0m = 32, MRM1m = 33, MRM2m = 34, MRM3m = 35,
    116     MRM4m = 36, MRM5m = 37, MRM6m = 38, MRM7m = 39,
    117     MRMDestReg     = 40,
    118     MRMSrcReg      = 41,
    119     MRMSrcReg4VOp3 = 42,
    120     MRMSrcRegOp4   = 43,
    121     MRMSrcRegCC    = 44,
    122     MRMXrCC = 46, MRMXr = 47,
    123     MRM0r = 48, MRM1r = 49, MRM2r = 50, MRM3r = 51,
    124     MRM4r = 52, MRM5r = 53, MRM6r = 54, MRM7r = 55,
    125     MRM0X = 56, MRM1X = 57, MRM2X = 58, MRM3X = 59,
    126     MRM4X = 60, MRM5X = 61, MRM6X = 62, MRM7X = 63,
    127 #define MAP(from, to) MRM_##from = to,
    128     X86_INSTR_MRM_MAPPING
    129 #undef MAP
    130   };
    131 
    132   enum {
    133     OB = 0, TB = 1, T8 = 2, TA = 3, XOP8 = 4, XOP9 = 5, XOPA = 6, ThreeDNow = 7
    134   };
    135 
    136   enum {
    137     PD = 1, XS = 2, XD = 3, PS = 4
    138   };
    139 
    140   enum {
    141     VEX = 1, XOP = 2, EVEX = 3
    142   };
    143 
    144   enum {
    145     OpSize16 = 1, OpSize32 = 2
    146   };
    147 
    148   enum {
    149     AdSize16 = 1, AdSize32 = 2, AdSize64 = 3
    150   };
    151 }
    152 
    153 namespace X86Disassembler {
    154 
    155 /// RecognizableInstr - Encapsulates all information required to decode a single
    156 ///   instruction, as extracted from the LLVM instruction tables.  Has methods
    157 ///   to interpret the information available in the LLVM tables, and to emit the
    158 ///   instruction into DisassemblerTables.
    159 class RecognizableInstr {
    160 private:
    161   /// The opcode of the instruction, as used in an MCInst
    162   InstrUID UID;
    163   /// The record from the .td files corresponding to this instruction
    164   const Record* Rec;
    165   /// The OpPrefix field from the record
    166   uint8_t OpPrefix;
    167   /// The OpMap field from the record
    168   uint8_t OpMap;
    169   /// The opcode field from the record; this is the opcode used in the Intel
    170   /// encoding and therefore distinct from the UID
    171   uint8_t Opcode;
    172   /// The form field from the record
    173   uint8_t Form;
    174   // The encoding field from the record
    175   uint8_t Encoding;
    176   /// The OpSize field from the record
    177   uint8_t OpSize;
    178   /// The AdSize field from the record
    179   uint8_t AdSize;
    180   /// The hasREX_WPrefix field from the record
    181   bool HasREX_WPrefix;
    182   /// The hasVEX_4V field from the record
    183   bool HasVEX_4V;
    184   /// The HasVEX_WPrefix field from the record
    185   bool HasVEX_W;
    186   /// The IgnoresVEX_W field from the record
    187   bool IgnoresVEX_W;
    188   /// Inferred from the operands; indicates whether the L bit in the VEX prefix is set
    189   bool HasVEX_LPrefix;
    190   /// The ignoreVEX_L field from the record
    191   bool IgnoresVEX_L;
    192   /// The hasEVEX_L2Prefix field from the record
    193   bool HasEVEX_L2Prefix;
    194   /// The hasEVEX_K field from the record
    195   bool HasEVEX_K;
    196   /// The hasEVEX_KZ field from the record
    197   bool HasEVEX_KZ;
    198   /// The hasEVEX_B field from the record
    199   bool HasEVEX_B;
    200   /// Indicates that the instruction uses the L and L' fields for RC.
    201   bool EncodeRC;
    202   /// The isCodeGenOnly field from the record
    203   bool IsCodeGenOnly;
    204   /// The ForceDisassemble field from the record
    205   bool ForceDisassemble;
    206   // The CD8_Scale field from the record
    207   uint8_t CD8_Scale;
    208   // Whether the instruction has the predicate "In64BitMode"
    209   bool Is64Bit;
    210   // Whether the instruction has the predicate "In32BitMode"
    211   bool Is32Bit;
    212 
    213   /// The instruction name as listed in the tables
    214   std::string Name;
    215 
    216   /// Indicates whether the instruction should be emitted into the decode
    217   /// tables; regardless, it will be emitted into the instruction info table
    218   bool ShouldBeEmitted;
    219 
    220   /// The operands of the instruction, as listed in the CodeGenInstruction.
    221   /// They are not one-to-one with operands listed in the MCInst; for example,
    222   /// memory operands expand to 5 operands in the MCInst
    223   const std::vector<CGIOperandList::OperandInfo>* Operands;
    224 
    225   /// The description of the instruction that is emitted into the instruction
    226   /// info table
    227   InstructionSpecifier* Spec;
    228 
    229   /// insnContext - Returns the primary context in which the instruction is
    230   ///   valid.
    231   ///
    232   /// @return - The context in which the instruction is valid.
    233   InstructionContext insnContext() const;
    234 
    235   /// typeFromString - Translates an operand type from the string provided in
    236   ///   the LLVM tables to an OperandType for use in the operand specifier.
    237   ///
    238   /// @param s              - The string, as extracted by calling Rec->getName()
    239   ///                         on a CodeGenInstruction::OperandInfo.
    240   /// @param hasREX_WPrefix - Indicates whether the instruction has a REX.W
    241   ///                         prefix.  If it does, 32-bit register operands stay
    242   ///                         32-bit regardless of the operand size.
    243   /// @param OpSize           Indicates the operand size of the instruction.
    244   ///                         If register size does not match OpSize, then
    245   ///                         register sizes keep their size.
    246   /// @return               - The operand's type.
    247   static OperandType typeFromString(const std::string& s,
    248                                     bool hasREX_WPrefix, uint8_t OpSize);
    249 
    250   /// immediateEncodingFromString - Translates an immediate encoding from the
    251   ///   string provided in the LLVM tables to an OperandEncoding for use in
    252   ///   the operand specifier.
    253   ///
    254   /// @param s       - See typeFromString().
    255   /// @param OpSize  - Indicates whether this is an OpSize16 instruction.
    256   ///                  If it is not, then 16-bit immediate operands stay 16-bit.
    257   /// @return        - The operand's encoding.
    258   static OperandEncoding immediateEncodingFromString(const std::string &s,
    259                                                      uint8_t OpSize);
    260 
    261   /// rmRegisterEncodingFromString - Like immediateEncodingFromString, but
    262   ///   handles operands that are in the REG field of the ModR/M byte.
    263   static OperandEncoding rmRegisterEncodingFromString(const std::string &s,
    264                                                       uint8_t OpSize);
    265 
    266   /// rmRegisterEncodingFromString - Like immediateEncodingFromString, but
    267   ///   handles operands that are in the REG field of the ModR/M byte.
    268   static OperandEncoding roRegisterEncodingFromString(const std::string &s,
    269                                                       uint8_t OpSize);
    270   static OperandEncoding memoryEncodingFromString(const std::string &s,
    271                                                   uint8_t OpSize);
    272   static OperandEncoding relocationEncodingFromString(const std::string &s,
    273                                                       uint8_t OpSize);
    274   static OperandEncoding opcodeModifierEncodingFromString(const std::string &s,
    275                                                           uint8_t OpSize);
    276   static OperandEncoding vvvvRegisterEncodingFromString(const std::string &s,
    277                                                         uint8_t OpSize);
    278   static OperandEncoding writemaskRegisterEncodingFromString(const std::string &s,
    279                                                              uint8_t OpSize);
    280 
    281   /// Adjust the encoding type for an operand based on the instruction.
    282   void adjustOperandEncoding(OperandEncoding &encoding);
    283 
    284   /// handleOperand - Converts a single operand from the LLVM table format to
    285   ///   the emitted table format, handling any duplicate operands it encounters
    286   ///   and then one non-duplicate.
    287   ///
    288   /// @param optional             - Determines whether to assert that the
    289   ///                               operand exists.
    290   /// @param operandIndex         - The index into the generated operand table.
    291   ///                               Incremented by this function one or more
    292   ///                               times to reflect possible duplicate
    293   ///                               operands).
    294   /// @param physicalOperandIndex - The index of the current operand into the
    295   ///                               set of non-duplicate ('physical') operands.
    296   ///                               Incremented by this function once.
    297   /// @param numPhysicalOperands  - The number of non-duplicate operands in the
    298   ///                               instructions.
    299   /// @param operandMapping       - The operand mapping, which has an entry for
    300   ///                               each operand that indicates whether it is a
    301   ///                               duplicate, and of what.
    302   void handleOperand(bool optional,
    303                      unsigned &operandIndex,
    304                      unsigned &physicalOperandIndex,
    305                      unsigned numPhysicalOperands,
    306                      const unsigned *operandMapping,
    307                      OperandEncoding (*encodingFromString)
    308                        (const std::string&,
    309                         uint8_t OpSize));
    310 
    311   /// shouldBeEmitted - Returns the shouldBeEmitted field.  Although filter()
    312   ///   filters out many instructions, at various points in decoding we
    313   ///   determine that the instruction should not actually be decodable.  In
    314   ///   particular, MMX MOV instructions aren't emitted, but they're only
    315   ///   identified during operand parsing.
    316   ///
    317   /// @return - true if at this point we believe the instruction should be
    318   ///   emitted; false if not.  This will return false if filter() returns false
    319   ///   once emitInstructionSpecifier() has been called.
    320   bool shouldBeEmitted() const {
    321     return ShouldBeEmitted;
    322   }
    323 
    324   /// emitInstructionSpecifier - Loads the instruction specifier for the current
    325   ///   instruction into a DisassemblerTables.
    326   ///
    327   void emitInstructionSpecifier();
    328 
    329   /// emitDecodePath - Populates the proper fields in the decode tables
    330   ///   corresponding to the decode paths for this instruction.
    331   ///
    332   /// \param tables The DisassemblerTables to populate with the decode
    333   ///               decode information for the current instruction.
    334   void emitDecodePath(DisassemblerTables &tables) const;
    335 
    336   /// Constructor - Initializes a RecognizableInstr with the appropriate fields
    337   ///   from a CodeGenInstruction.
    338   ///
    339   /// \param tables The DisassemblerTables that the specifier will be added to.
    340   /// \param insn   The CodeGenInstruction to extract information from.
    341   /// \param uid    The unique ID of the current instruction.
    342   RecognizableInstr(DisassemblerTables &tables,
    343                     const CodeGenInstruction &insn,
    344                     InstrUID uid);
    345 public:
    346   /// processInstr - Accepts a CodeGenInstruction and loads decode information
    347   ///   for it into a DisassemblerTables if appropriate.
    348   ///
    349   /// \param tables The DiassemblerTables to be populated with decode
    350   ///               information.
    351   /// \param insn   The CodeGenInstruction to be used as a source for this
    352   ///               information.
    353   /// \param uid    The unique ID of the instruction.
    354   static void processInstr(DisassemblerTables &tables,
    355                            const CodeGenInstruction &insn,
    356                            InstrUID uid);
    357 };
    358 
    359 } // namespace X86Disassembler
    360 
    361 } // namespace llvm
    362 
    363 #endif
    364