FaultMaps.h revision 309124 
1//===------------------- FaultMaps.h - The "FaultMaps" section --*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9
10#ifndef LLVM_CODEGEN_FAULTMAPS_H
11#define LLVM_CODEGEN_FAULTMAPS_H
12
13#include "llvm/MC/MCSymbol.h"
14#include "llvm/Support/Endian.h"
15#include "llvm/Support/Format.h"
16
17#include <vector>
18#include <map>
19
20namespace llvm {
21
22class AsmPrinter;
23class MCExpr;
24class MCSymbol;
25class MCStreamer;
26
27class FaultMaps {
28public:
29  enum FaultKind { FaultingLoad = 1, FaultKindMax };
30
31  static const char *faultTypeToString(FaultKind);
32
33  explicit FaultMaps(AsmPrinter &AP);
34
35  void recordFaultingOp(FaultKind FaultTy, const MCSymbol *HandlerLabel);
36  void serializeToFaultMapSection();
37
38private:
39  static const char *WFMP;
40
41  struct FaultInfo {
42    FaultKind Kind;
43    const MCExpr *FaultingOffsetExpr;
44    const MCExpr *HandlerOffsetExpr;
45
46    FaultInfo()
47        : Kind(FaultKindMax), FaultingOffsetExpr(nullptr),
48          HandlerOffsetExpr(nullptr) {}
49
50    explicit FaultInfo(FaultMaps::FaultKind Kind, const MCExpr *FaultingOffset,
51                       const MCExpr *HandlerOffset)
52        : Kind(Kind), FaultingOffsetExpr(FaultingOffset),
53          HandlerOffsetExpr(HandlerOffset) {}
54  };
55
56  typedef std::vector<FaultInfo> FunctionFaultInfos;
57
58  // We'd like to keep a stable iteration order for FunctionInfos to help
59  // FileCheck based testing.
60  struct MCSymbolComparator {
61    bool operator()(const MCSymbol *LHS, const MCSymbol *RHS) const {
62      return LHS->getName() < RHS->getName();
63    }
64  };
65
66  std::map<const MCSymbol *, FunctionFaultInfos, MCSymbolComparator>
67      FunctionInfos;
68  AsmPrinter &AP;
69
70  void emitFunctionInfo(const MCSymbol *FnLabel, const FunctionFaultInfos &FFI);
71};
72
73/// A parser for the __llvm_faultmaps section generated by the FaultMaps class
74/// above.  This parser is version locked with with the __llvm_faultmaps section
75/// generated by the version of LLVM that includes it.  No guarantees are made
76/// with respect to forward or backward compatibility.
77class FaultMapParser {
78  typedef uint8_t FaultMapVersionType;
79  static const size_t FaultMapVersionOffset = 0;
80
81  typedef uint8_t Reserved0Type;
82  static const size_t Reserved0Offset =
83      FaultMapVersionOffset + sizeof(FaultMapVersionType);
84
85  typedef uint16_t Reserved1Type;
86  static const size_t Reserved1Offset = Reserved0Offset + sizeof(Reserved0Type);
87
88  typedef uint32_t NumFunctionsType;
89  static const size_t NumFunctionsOffset =
90      Reserved1Offset + sizeof(Reserved1Type);
91
92  static const size_t FunctionInfosOffset =
93      NumFunctionsOffset + sizeof(NumFunctionsType);
94
95  const uint8_t *P;
96  const uint8_t *E;
97
98  template <typename T> static T read(const uint8_t *P, const uint8_t *E) {
99    assert(P + sizeof(T) <= E && "out of bounds read!");
100    return support::endian::read<T, support::little, 1>(P);
101  }
102
103public:
104  class FunctionFaultInfoAccessor {
105    typedef uint32_t FaultKindType;
106    static const size_t FaultKindOffset = 0;
107
108    typedef uint32_t FaultingPCOffsetType;
109    static const size_t FaultingPCOffsetOffset =
110        FaultKindOffset + sizeof(FaultKindType);
111
112    typedef uint32_t HandlerPCOffsetType;
113    static const size_t HandlerPCOffsetOffset =
114        FaultingPCOffsetOffset + sizeof(FaultingPCOffsetType);
115
116    const uint8_t *P;
117    const uint8_t *E;
118
119  public:
120    static const size_t Size =
121        HandlerPCOffsetOffset + sizeof(HandlerPCOffsetType);
122
123    explicit FunctionFaultInfoAccessor(const uint8_t *P, const uint8_t *E)
124        : P(P), E(E) {}
125
126    FaultKindType getFaultKind() const {
127      return read<FaultKindType>(P + FaultKindOffset, E);
128    }
129
130    FaultingPCOffsetType getFaultingPCOffset() const {
131      return read<FaultingPCOffsetType>(P + FaultingPCOffsetOffset, E);
132    }
133
134    HandlerPCOffsetType getHandlerPCOffset() const {
135      return read<HandlerPCOffsetType>(P + HandlerPCOffsetOffset, E);
136    }
137  };
138
139  class FunctionInfoAccessor {
140    typedef uint64_t FunctionAddrType;
141    static const size_t FunctionAddrOffset = 0;
142
143    typedef uint32_t NumFaultingPCsType;
144    static const size_t NumFaultingPCsOffset =
145        FunctionAddrOffset + sizeof(FunctionAddrType);
146
147    typedef uint32_t ReservedType;
148    static const size_t ReservedOffset =
149        NumFaultingPCsOffset + sizeof(NumFaultingPCsType);
150
151    static const size_t FunctionFaultInfosOffset =
152        ReservedOffset + sizeof(ReservedType);
153
154    static const size_t FunctionInfoHeaderSize = FunctionFaultInfosOffset;
155
156    const uint8_t *P;
157    const uint8_t *E;
158
159  public:
160    FunctionInfoAccessor() : P(nullptr), E(nullptr) {}
161
162    explicit FunctionInfoAccessor(const uint8_t *P, const uint8_t *E)
163        : P(P), E(E) {}
164
165    FunctionAddrType getFunctionAddr() const {
166      return read<FunctionAddrType>(P + FunctionAddrOffset, E);
167    }
168
169    NumFaultingPCsType getNumFaultingPCs() const {
170      return read<NumFaultingPCsType>(P + NumFaultingPCsOffset, E);
171    }
172
173    FunctionFaultInfoAccessor getFunctionFaultInfoAt(uint32_t Index) const {
174      assert(Index < getNumFaultingPCs() && "index out of bounds!");
175      const uint8_t *Begin = P + FunctionFaultInfosOffset +
176                             FunctionFaultInfoAccessor::Size * Index;
177      return FunctionFaultInfoAccessor(Begin, E);
178    }
179
180    FunctionInfoAccessor getNextFunctionInfo() const {
181      size_t MySize = FunctionInfoHeaderSize +
182                      getNumFaultingPCs() * FunctionFaultInfoAccessor::Size;
183
184      const uint8_t *Begin = P + MySize;
185      assert(Begin < E && "out of bounds!");
186      return FunctionInfoAccessor(Begin, E);
187    }
188  };
189
190  explicit FaultMapParser(const uint8_t *Begin, const uint8_t *End)
191      : P(Begin), E(End) {}
192
193  FaultMapVersionType getFaultMapVersion() const {
194    auto Version = read<FaultMapVersionType>(P + FaultMapVersionOffset, E);
195    assert(Version == 1 && "only version 1 supported!");
196    return Version;
197  }
198
199  NumFunctionsType getNumFunctions() const {
200    return read<NumFunctionsType>(P + NumFunctionsOffset, E);
201  }
202
203  FunctionInfoAccessor getFirstFunctionInfo() const {
204    const uint8_t *Begin = P + FunctionInfosOffset;
205    return FunctionInfoAccessor(Begin, E);
206  }
207};
208
209raw_ostream &
210operator<<(raw_ostream &OS, const FaultMapParser::FunctionFaultInfoAccessor &);
211
212raw_ostream &operator<<(raw_ostream &OS,
213                        const FaultMapParser::FunctionInfoAccessor &);
214
215raw_ostream &operator<<(raw_ostream &OS, const FaultMapParser &);
216
217} // namespace llvm
218
219#endif
220