EhFrameReader.h revision 37b74a387bb3993387029859c2d9d051c41c724e 
1//===- EhFrameReader.h ----------------------------------------------------===//
2//
3//                     The MCLinker Project
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9#ifndef MCLD_LD_EHFRAMEREADER_H_
10#define MCLD_LD_EHFRAMEREADER_H_
11#include "mcld/LD/EhFrame.h"
12
13#include <llvm/ADT/StringRef.h>
14#include <llvm/Support/DataTypes.h>
15
16namespace mcld {
17
18class Input;
19class LDSection;
20
21/** \class EhFrameReader
22 *  \brief EhFrameReader reads .eh_frame section
23 *
24 *  EhFrameReader is responsible to parse the input eh_frame sections and create
25 *  the corresponding CIE and FDE entries.
26 */
27class EhFrameReader {
28 public:
29  typedef const char* ConstAddress;
30  typedef char* Address;
31
32 public:
33  /// read - read an .eh_frame section and create the corresponding
34  /// CIEs and FDEs
35  /// @param pInput [in] the Input contains this eh_frame
36  /// @param pEhFrame [inout] the input eh_frame
37  /// @return if we read all CIEs and FDEs successfully, return true. Otherwise,
38  /// return false;
39  template <size_t BITCLASS, bool SAME_ENDIAN>
40  bool read(Input& pInput, EhFrame& pEhFrame);
41
42 private:
43  enum TokenKind { CIE, FDE, Terminator, Unknown, NumOfTokenKinds };
44
45  enum State { Q0, Q1, Accept, NumOfStates = 2, Reject = -1 };
46
47  struct Token {
48    TokenKind kind;
49    size_t file_off;
50    size_t data_off;
51    uint64_t size;
52  };
53
54  /// Action - the transition function of autometa.
55  /// @param pEhFrame - the output .eh_frame section
56  /// @param pSection - the input .eh_frame section
57  /// @param pRegion - the memory region that needs to handle with.
58  typedef bool (*Action)(EhFrame& pEhFrame,
59                         llvm::StringRef pRegion,
60                         const Token& pToken);
61
62 private:
63  /// scan - scan pData from pHandler for a token.
64  template <bool SAME_ENDIAN>
65  Token scan(ConstAddress pHandler,
66             uint64_t pOffset,
67             llvm::StringRef pData) const;
68
69  static bool addCIE(EhFrame& pEhFrame,
70                     llvm::StringRef pRegion,
71                     const Token& pToken);
72
73  static bool addFDE(EhFrame& pEhFrame,
74                     llvm::StringRef pRegion,
75                     const Token& pToken);
76
77  static bool addTerm(EhFrame& pEhFrame,
78                      llvm::StringRef pRegion,
79                      const Token& pToken);
80
81  static bool reject(EhFrame& pEhFrame,
82                     llvm::StringRef pRegion,
83                     const Token& pToken);
84};
85
86template <>
87bool EhFrameReader::read<32, true>(Input& pInput, EhFrame& pEhFrame);
88
89template <>
90EhFrameReader::Token EhFrameReader::scan<true>(ConstAddress pHandler,
91                                               uint64_t pOffset,
92                                               llvm::StringRef pData) const;
93
94}  // namespace mcld
95
96#endif  // MCLD_LD_EHFRAMEREADER_H_
97