reference, declarationdefinition
definition → references, declarations, derived classes, virtual overrides
reference to multiple definitions → definitions
unreferenced
    1
    2
    3
    4
    5
    6
    7
    8
    9
   10
   11
   12
   13
   14
   15
   16
   17
   18
   19
   20
   21
   22
   23
   24
   25
   26
   27
   28
   29
   30
   31
   32
   33
   34
   35
   36
   37
   38
   39
   40
   41
   42
   43
   44
   45
   46
   47
   48
   49
   50
   51
   52
   53
   54
   55
   56
   57
   58
   59
   60
   61
   62
   63
   64
   65
   66
   67
   68
   69
   70
   71
   72
   73
   74
   75
   76
   77
   78
   79
   80
   81
   82
   83
   84
   85
   86
   87
   88
   89
   90
   91
   92
   93
   94
   95
   96
   97
   98
   99
  100
  101
  102
  103
  104
  105
  106
  107
  108
  109
  110
  111
  112
  113
  114
  115
  116
  117
  118
  119
  120
  121
  122
  123
  124
  125
  126
  127
  128
  129
  130
  131
  132
  133
  134
  135
  136
  137
  138
  139
  140
  141
  142
  143
  144
  145
  146
  147
  148
  149
  150
  151
  152
  153
  154
  155
  156
  157
  158
  159
  160
  161
  162
  163
  164
  165
  166
  167
  168
  169
  170
  171
  172
  173
  174
  175
  176
  177
  178
  179
  180
  181
  182
//===- BitCodes.h - Enum values for the bitcode format ----------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This header Bitcode enum values.
//
// The enum values defined in this file should be considered permanent.  If
// new features are added, they should have values added at the end of the
// respective lists.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_BITCODE_BITCODES_H
#define LLVM_BITCODE_BITCODES_H

#include "llvm/ADT/SmallVector.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/ErrorHandling.h"
#include <cassert>

namespace llvm {
/// Offsets of the 32-bit fields of bitcode wrapper header.
static const unsigned BWH_MagicField = 0 * 4;
static const unsigned BWH_VersionField = 1 * 4;
static const unsigned BWH_OffsetField = 2 * 4;
static const unsigned BWH_SizeField = 3 * 4;
static const unsigned BWH_CPUTypeField = 4 * 4;
static const unsigned BWH_HeaderSize = 5 * 4;

namespace bitc {
  enum StandardWidths {
    BlockIDWidth   = 8,  // We use VBR-8 for block IDs.
    CodeLenWidth   = 4,  // Codelen are VBR-4.
    BlockSizeWidth = 32  // BlockSize up to 2^32 32-bit words = 16GB per block.
  };

  // The standard abbrev namespace always has a way to exit a block, enter a
  // nested block, define abbrevs, and define an unabbreviated record.
  enum FixedAbbrevIDs {
    END_BLOCK = 0,  // Must be zero to guarantee termination for broken bitcode.
    ENTER_SUBBLOCK = 1,

    /// DEFINE_ABBREV - Defines an abbrev for the current block.  It consists
    /// of a vbr5 for # operand infos.  Each operand info is emitted with a
    /// single bit to indicate if it is a literal encoding.  If so, the value is
    /// emitted with a vbr8.  If not, the encoding is emitted as 3 bits followed
    /// by the info value as a vbr5 if needed.
    DEFINE_ABBREV = 2,

    // UNABBREV_RECORDs are emitted with a vbr6 for the record code, followed by
    // a vbr6 for the # operands, followed by vbr6's for each operand.
    UNABBREV_RECORD = 3,

    // This is not a code, this is a marker for the first abbrev assignment.
    FIRST_APPLICATION_ABBREV = 4
  };

  /// StandardBlockIDs - All bitcode files can optionally include a BLOCKINFO
  /// block, which contains metadata about other blocks in the file.
  enum StandardBlockIDs {
    /// BLOCKINFO_BLOCK is used to define metadata about blocks, for example,
    /// standard abbrevs that should be available to all blocks of a specified
    /// ID.
    BLOCKINFO_BLOCK_ID = 0,

    // Block IDs 1-7 are reserved for future expansion.
    FIRST_APPLICATION_BLOCKID = 8
  };

  /// BlockInfoCodes - The blockinfo block contains metadata about user-defined
  /// blocks.
  enum BlockInfoCodes {
    // DEFINE_ABBREV has magic semantics here, applying to the current SETBID'd
    // block, instead of the BlockInfo block.

    BLOCKINFO_CODE_SETBID        = 1, // SETBID: [blockid#]
    BLOCKINFO_CODE_BLOCKNAME     = 2, // BLOCKNAME: [name]
    BLOCKINFO_CODE_SETRECORDNAME = 3  // BLOCKINFO_CODE_SETRECORDNAME:
                                      //                             [id, name]
  };

} // End bitc namespace

/// BitCodeAbbrevOp - This describes one or more operands in an abbreviation.
/// This is actually a union of two different things:
///   1. It could be a literal integer value ("the operand is always 17").
///   2. It could be an encoding specification ("this operand encoded like so").
///
class BitCodeAbbrevOp {
  uint64_t Val;           // A literal value or data for an encoding.
  bool IsLiteral : 1;     // Indicate whether this is a literal value or not.
  unsigned Enc   : 3;     // The encoding to use.
public:
  enum Encoding {
    Fixed = 1,  // A fixed width field, Val specifies number of bits.
    VBR   = 2,  // A VBR field where Val specifies the width of each chunk.
    Array = 3,  // A sequence of fields, next field species elt encoding.
    Char6 = 4,  // A 6-bit fixed field which maps to [a-zA-Z0-9._].
    Blob  = 5   // 32-bit aligned array of 8-bit characters.
  };

  explicit BitCodeAbbrevOp(uint64_t V) :  Val(V), IsLiteral(true) {}
  explicit BitCodeAbbrevOp(Encoding E, uint64_t Data = 0)
    : Val(Data), IsLiteral(false), Enc(E) {}

  bool isLiteral() const  { return IsLiteral; }
  bool isEncoding() const { return !IsLiteral; }

  // Accessors for literals.
  uint64_t getLiteralValue() const { assert(isLiteral()); return Val; }

  // Accessors for encoding info.
  Encoding getEncoding() const { assert(isEncoding()); return (Encoding)Enc; }
  uint64_t getEncodingData() const {
    assert(isEncoding() && hasEncodingData());
    return Val;
  }

  bool hasEncodingData() const { return hasEncodingData(getEncoding()); }
  static bool hasEncodingData(Encoding E) {
    switch (E) {
    case Fixed:
    case VBR:
      return true;
    case Array:
    case Char6:
    case Blob:
      return false;
    }
    report_fatal_error("Invalid encoding");
  }

  /// isChar6 - Return true if this character is legal in the Char6 encoding.
  static bool isChar6(char C) {
    if (C >= 'a' && C <= 'z') return true;
    if (C >= 'A' && C <= 'Z') return true;
    if (C >= '0' && C <= '9') return true;
    if (C == '.' || C == '_') return true;
    return false;
  }
  static unsigned EncodeChar6(char C) {
    if (C >= 'a' && C <= 'z') return C-'a';
    if (C >= 'A' && C <= 'Z') return C-'A'+26;
    if (C >= '0' && C <= '9') return C-'0'+26+26;
    if (C == '.')             return 62;
    if (C == '_')             return 63;
    llvm_unreachable("Not a value Char6 character!");
  }

  static char DecodeChar6(unsigned V) {
    assert((V & ~63) == 0 && "Not a Char6 encoded character!");
    return "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789._"
        [V];
  }

};

/// BitCodeAbbrev - This class represents an abbreviation record.  An
/// abbreviation allows a complex record that has redundancy to be stored in a
/// specialized format instead of the fully-general, fully-vbr, format.
class BitCodeAbbrev {
  SmallVector<BitCodeAbbrevOp, 32> OperandList;

public:
  unsigned getNumOperandInfos() const {
    return static_cast<unsigned>(OperandList.size());
  }
  const BitCodeAbbrevOp &getOperandInfo(unsigned N) const {
    return OperandList[N];
  }

  void Add(const BitCodeAbbrevOp &OpInfo) {
    OperandList.push_back(OpInfo);
  }
};
} // End llvm namespace

#endif