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
  183
  184
  185
  186
  187
  188
  189
  190
  191
  192
  193
  194
  195
  196
  197
  198
  199
  200
  201
  202
  203
  204
  205
  206
  207
  208
  209
  210
  211
  212
  213
  214
  215
  216
  217
//===- FaultMaps.h - The "FaultMaps" section --------------------*- 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_FAULTMAPS_H
#define LLVM_CODEGEN_FAULTMAPS_H

#include "llvm/MC/MCSymbol.h"
#include "llvm/Support/Endian.h"
#include <cassert>
#include <cstddef>
#include <cstdint>
#include <map>
#include <vector>

namespace llvm {

class AsmPrinter;
class MCExpr;
class raw_ostream;

class FaultMaps {
public:
  enum FaultKind {
    FaultingLoad = 1,
    FaultingLoadStore,
    FaultingStore,
    FaultKindMax
  };

  explicit FaultMaps(AsmPrinter &AP);

  static const char *faultTypeToString(FaultKind);

  void recordFaultingOp(FaultKind FaultTy, const MCSymbol *HandlerLabel);
  void serializeToFaultMapSection();
  void reset() {
    FunctionInfos.clear();
  }

private:
  static const char *WFMP;

  struct FaultInfo {
    FaultKind Kind = FaultKindMax;
    const MCExpr *FaultingOffsetExpr = nullptr;
    const MCExpr *HandlerOffsetExpr = nullptr;

    FaultInfo() = default;

    explicit FaultInfo(FaultMaps::FaultKind Kind, const MCExpr *FaultingOffset,
                       const MCExpr *HandlerOffset)
        : Kind(Kind), FaultingOffsetExpr(FaultingOffset),
          HandlerOffsetExpr(HandlerOffset) {}
  };

  using FunctionFaultInfos = std::vector<FaultInfo>;

  // We'd like to keep a stable iteration order for FunctionInfos to help
  // FileCheck based testing.
  struct MCSymbolComparator {
    bool operator()(const MCSymbol *LHS, const MCSymbol *RHS) const {
      return LHS->getName() < RHS->getName();
    }
  };

  std::map<const MCSymbol *, FunctionFaultInfos, MCSymbolComparator>
      FunctionInfos;
  AsmPrinter &AP;

  void emitFunctionInfo(const MCSymbol *FnLabel, const FunctionFaultInfos &FFI);
};

/// A parser for the __llvm_faultmaps section generated by the FaultMaps class
/// above.  This parser is version locked with with the __llvm_faultmaps section
/// generated by the version of LLVM that includes it.  No guarantees are made
/// with respect to forward or backward compatibility.
class FaultMapParser {
  using FaultMapVersionType = uint8_t;
  using Reserved0Type = uint8_t;
  using Reserved1Type = uint16_t;
  using NumFunctionsType = uint32_t;

  static const size_t FaultMapVersionOffset = 0;
  static const size_t Reserved0Offset =
      FaultMapVersionOffset + sizeof(FaultMapVersionType);
  static const size_t Reserved1Offset = Reserved0Offset + sizeof(Reserved0Type);
  static const size_t NumFunctionsOffset =
      Reserved1Offset + sizeof(Reserved1Type);
  static const size_t FunctionInfosOffset =
      NumFunctionsOffset + sizeof(NumFunctionsType);

  const uint8_t *P;
  const uint8_t *E;

  template <typename T> static T read(const uint8_t *P, const uint8_t *E) {
    assert(P + sizeof(T) <= E && "out of bounds read!");
    return support::endian::read<T, support::little, 1>(P);
  }

public:
  class FunctionFaultInfoAccessor {
    using FaultKindType = uint32_t;
    using FaultingPCOffsetType = uint32_t;
    using HandlerPCOffsetType = uint32_t;

    static const size_t FaultKindOffset = 0;
    static const size_t FaultingPCOffsetOffset =
        FaultKindOffset + sizeof(FaultKindType);
    static const size_t HandlerPCOffsetOffset =
        FaultingPCOffsetOffset + sizeof(FaultingPCOffsetType);

    const uint8_t *P;
    const uint8_t *E;

  public:
    static const size_t Size =
        HandlerPCOffsetOffset + sizeof(HandlerPCOffsetType);

    explicit FunctionFaultInfoAccessor(const uint8_t *P, const uint8_t *E)
        : P(P), E(E) {}

    FaultKindType getFaultKind() const {
      return read<FaultKindType>(P + FaultKindOffset, E);
    }

    FaultingPCOffsetType getFaultingPCOffset() const {
      return read<FaultingPCOffsetType>(P + FaultingPCOffsetOffset, E);
    }

    HandlerPCOffsetType getHandlerPCOffset() const {
      return read<HandlerPCOffsetType>(P + HandlerPCOffsetOffset, E);
    }
  };

  class FunctionInfoAccessor {
    using FunctionAddrType = uint64_t;
    using NumFaultingPCsType = uint32_t;
    using ReservedType = uint32_t;

    static const size_t FunctionAddrOffset = 0;
    static const size_t NumFaultingPCsOffset =
        FunctionAddrOffset + sizeof(FunctionAddrType);
    static const size_t ReservedOffset =
        NumFaultingPCsOffset + sizeof(NumFaultingPCsType);
    static const size_t FunctionFaultInfosOffset =
        ReservedOffset + sizeof(ReservedType);
    static const size_t FunctionInfoHeaderSize = FunctionFaultInfosOffset;

    const uint8_t *P = nullptr;
    const uint8_t *E = nullptr;

  public:
    FunctionInfoAccessor() = default;

    explicit FunctionInfoAccessor(const uint8_t *P, const uint8_t *E)
        : P(P), E(E) {}

    FunctionAddrType getFunctionAddr() const {
      return read<FunctionAddrType>(P + FunctionAddrOffset, E);
    }

    NumFaultingPCsType getNumFaultingPCs() const {
      return read<NumFaultingPCsType>(P + NumFaultingPCsOffset, E);
    }

    FunctionFaultInfoAccessor getFunctionFaultInfoAt(uint32_t Index) const {
      assert(Index < getNumFaultingPCs() && "index out of bounds!");
      const uint8_t *Begin = P + FunctionFaultInfosOffset +
                             FunctionFaultInfoAccessor::Size * Index;
      return FunctionFaultInfoAccessor(Begin, E);
    }

    FunctionInfoAccessor getNextFunctionInfo() const {
      size_t MySize = FunctionInfoHeaderSize +
                      getNumFaultingPCs() * FunctionFaultInfoAccessor::Size;

      const uint8_t *Begin = P + MySize;
      assert(Begin < E && "out of bounds!");
      return FunctionInfoAccessor(Begin, E);
    }
  };

  explicit FaultMapParser(const uint8_t *Begin, const uint8_t *End)
      : P(Begin), E(End) {}

  FaultMapVersionType getFaultMapVersion() const {
    auto Version = read<FaultMapVersionType>(P + FaultMapVersionOffset, E);
    assert(Version == 1 && "only version 1 supported!");
    return Version;
  }

  NumFunctionsType getNumFunctions() const {
    return read<NumFunctionsType>(P + NumFunctionsOffset, E);
  }

  FunctionInfoAccessor getFirstFunctionInfo() const {
    const uint8_t *Begin = P + FunctionInfosOffset;
    return FunctionInfoAccessor(Begin, E);
  }
};

raw_ostream &
operator<<(raw_ostream &OS, const FaultMapParser::FunctionFaultInfoAccessor &);

raw_ostream &operator<<(raw_ostream &OS,
                        const FaultMapParser::FunctionInfoAccessor &);

raw_ostream &operator<<(raw_ostream &OS, const FaultMapParser &);

} // end namespace llvm

#endif // LLVM_CODEGEN_FAULTMAPS_H