FaultMaps.h revision 285181 
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/ADT/DenseMap.h"
14#include "llvm/MC/MCSymbol.h"
15#include "llvm/Support/Endian.h"
16#include "llvm/Support/Format.h"
17
18#include <vector>
19#include <map>
20
21namespace llvm {
22
23class AsmPrinter;
24class MCExpr;
25class MCSymbol;
26class MCStreamer;
27
28class FaultMaps {
29public:
30  enum FaultKind { FaultingLoad = 1, FaultKindMax };
31
32  static const char *faultTypeToString(FaultKind);
33
34  explicit FaultMaps(AsmPrinter &AP);
35
36  void recordFaultingOp(FaultKind FaultTy, const MCSymbol *HandlerLabel);
37  void serializeToFaultMapSection();
38
39private:
40  static const char *WFMP;
41
42  struct FaultInfo {
43    FaultKind Kind;
44    const MCExpr *FaultingOffsetExpr;
45    const MCExpr *HandlerOffsetExpr;
46
47    FaultInfo()
48        : Kind(FaultKindMax), FaultingOffsetExpr(nullptr),
49          HandlerOffsetExpr(nullptr) {}
50
51    explicit FaultInfo(FaultMaps::FaultKind Kind, const MCExpr *FaultingOffset,
52                       const MCExpr *HandlerOffset)
53        : Kind(Kind), FaultingOffsetExpr(FaultingOffset),
54          HandlerOffsetExpr(HandlerOffset) {}
55  };
56
57  typedef std::vector<FaultInfo> FunctionFaultInfos;
58
59  // We'd like to keep a stable iteration order for FunctionInfos to help
60  // FileCheck based testing.
61  struct MCSymbolComparator {
62    bool operator()(const MCSymbol *LHS, const MCSymbol *RHS) const {
63      return LHS->getName() < RHS->getName();
64    }
65  };
66
67  std::map<const MCSymbol *, FunctionFaultInfos, MCSymbolComparator>
68      FunctionInfos;
69  AsmPrinter &AP;
70
71  void emitFunctionInfo(const MCSymbol *FnLabel, const FunctionFaultInfos &FFI);
72};
73
74/// A parser for the __llvm_faultmaps section generated by the FaultMaps class
75/// above.  This parser is version locked with with the __llvm_faultmaps section
76/// generated by the version of LLVM that includes it.  No guarantees are made
77/// with respect to forward or backward compatibility.
78class FaultMapParser {
79  typedef uint8_t FaultMapVersionType;
80  static const size_t FaultMapVersionOffset = 0;
81
82  typedef uint8_t Reserved0Type;
83  static const size_t Reserved0Offset =
84      FaultMapVersionOffset + sizeof(FaultMapVersionType);
85
86  typedef uint16_t Reserved1Type;
87  static const size_t Reserved1Offset = Reserved0Offset + sizeof(Reserved0Type);
88
89  typedef uint32_t NumFunctionsType;
90  static const size_t NumFunctionsOffset =
91      Reserved1Offset + sizeof(Reserved1Type);
92
93  static const size_t FunctionInfosOffset =
94      NumFunctionsOffset + sizeof(NumFunctionsType);
95
96  const uint8_t *P;
97  const uint8_t *E;
98
99  template <typename T> static T read(const uint8_t *P, const uint8_t *E) {
100    assert(P + sizeof(T) <= E && "out of bounds read!");
101    return support::endian::read<T, support::little, 1>(P);
102  }
103
104public:
105  class FunctionFaultInfoAccessor {
106    typedef uint32_t FaultKindType;
107    static const size_t FaultKindOffset = 0;
108
109    typedef uint32_t FaultingPCOffsetType;
110    static const size_t FaultingPCOffsetOffset =
111        FaultKindOffset + sizeof(FaultKindType);
112
113    typedef uint32_t HandlerPCOffsetType;
114    static const size_t HandlerPCOffsetOffset =
115        FaultingPCOffsetOffset + sizeof(FaultingPCOffsetType);
116
117    const uint8_t *P;
118    const uint8_t *E;
119
120  public:
121    static const size_t Size =
122        HandlerPCOffsetOffset + sizeof(HandlerPCOffsetType);
123
124    explicit FunctionFaultInfoAccessor(const uint8_t *P, const uint8_t *E)
125        : P(P), E(E) {}
126
127    FaultKindType getFaultKind() const {
128      return read<FaultKindType>(P + FaultKindOffset, E);
129    }
130
131    FaultingPCOffsetType getFaultingPCOffset() const {
132      return read<FaultingPCOffsetType>(P + FaultingPCOffsetOffset, E);
133    }
134
135    HandlerPCOffsetType getHandlerPCOffset() const {
136      return read<HandlerPCOffsetType>(P + HandlerPCOffsetOffset, E);
137    }
138  };
139
140  class FunctionInfoAccessor {
141    typedef uint64_t FunctionAddrType;
142    static const size_t FunctionAddrOffset = 0;
143
144    typedef uint32_t NumFaultingPCsType;
145    static const size_t NumFaultingPCsOffset =
146        FunctionAddrOffset + sizeof(FunctionAddrType);
147
148    typedef uint32_t ReservedType;
149    static const size_t ReservedOffset =
150        NumFaultingPCsOffset + sizeof(NumFaultingPCsType);
151
152    static const size_t FunctionFaultInfosOffset =
153        ReservedOffset + sizeof(ReservedType);
154
155    static const size_t FunctionInfoHeaderSize = FunctionFaultInfosOffset;
156
157    const uint8_t *P;
158    const uint8_t *E;
159
160  public:
161    FunctionInfoAccessor() : P(nullptr), E(nullptr) {}
162
163    explicit FunctionInfoAccessor(const uint8_t *P, const uint8_t *E)
164        : P(P), E(E) {}
165
166    FunctionAddrType getFunctionAddr() const {
167      return read<FunctionAddrType>(P + FunctionAddrOffset, E);
168    }
169
170    NumFaultingPCsType getNumFaultingPCs() const {
171      return read<NumFaultingPCsType>(P + NumFaultingPCsOffset, E);
172    }
173
174    FunctionFaultInfoAccessor getFunctionFaultInfoAt(uint32_t Index) const {
175      assert(Index < getNumFaultingPCs() && "index out of bounds!");
176      const uint8_t *Begin = P + FunctionFaultInfosOffset +
177                             FunctionFaultInfoAccessor::Size * Index;
178      return FunctionFaultInfoAccessor(Begin, E);
179    }
180
181    FunctionInfoAccessor getNextFunctionInfo() const {
182      size_t MySize = FunctionInfoHeaderSize +
183                      getNumFaultingPCs() * FunctionFaultInfoAccessor::Size;
184
185      const uint8_t *Begin = P + MySize;
186      assert(Begin < E && "out of bounds!");
187      return FunctionInfoAccessor(Begin, E);
188    }
189  };
190
191  explicit FaultMapParser(const uint8_t *Begin, const uint8_t *End)
192      : P(Begin), E(End) {}
193
194  FaultMapVersionType getFaultMapVersion() const {
195    auto Version = read<FaultMapVersionType>(P + FaultMapVersionOffset, E);
196    assert(Version == 1 && "only version 1 supported!");
197    return Version;
198  }
199
200  NumFunctionsType getNumFunctions() const {
201    return read<NumFunctionsType>(P + NumFunctionsOffset, E);
202  }
203
204  FunctionInfoAccessor getFirstFunctionInfo() const {
205    const uint8_t *Begin = P + FunctionInfosOffset;
206    return FunctionInfoAccessor(Begin, E);
207  }
208};
209
210raw_ostream &
211operator<<(raw_ostream &OS, const FaultMapParser::FunctionFaultInfoAccessor &);
212
213raw_ostream &operator<<(raw_ostream &OS,
214                        const FaultMapParser::FunctionInfoAccessor &);
215
216raw_ostream &operator<<(raw_ostream &OS, const FaultMapParser &);
217
218} // namespace llvm
219
220#endif
221