1//===-- llvm/MC/MCObjectSymbolizer.h --------------------------------------===//
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// This file declares the MCObjectSymbolizer class, an MCSymbolizer that is
11// backed by an object::ObjectFile.
12//
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_MC_MCOBJECTSYMBOLIZER_H
16#define LLVM_MC_MCOBJECTSYMBOLIZER_H
17
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/MC/MCSymbolizer.h"
20#include "llvm/Object/ObjectFile.h"
21#include <vector>
22
23namespace llvm {
24
25class MCExpr;
26class MCInst;
27class MCRelocationInfo;
28class raw_ostream;
29
30/// \brief An ObjectFile-backed symbolizer.
31class MCObjectSymbolizer : public MCSymbolizer {
32protected:
33  const object::ObjectFile *Obj;
34
35  // Map a load address to the first relocation that applies there. As far as I
36  // know, if there are several relocations at the exact same address, they are
37  // related and the others can be determined from the first that was found in
38  // the relocation table. For instance, on x86-64 mach-o, a SUBTRACTOR
39  // relocation (referencing the minuend symbol) is followed by an UNSIGNED
40  // relocation (referencing the subtrahend symbol).
41  const object::RelocationRef *findRelocationAt(uint64_t Addr);
42  const object::SectionRef *findSectionContaining(uint64_t Addr);
43
44  MCObjectSymbolizer(MCContext &Ctx, std::unique_ptr<MCRelocationInfo> RelInfo,
45                     const object::ObjectFile *Obj);
46
47public:
48  /// \name Overridden MCSymbolizer methods:
49  /// @{
50  bool tryAddingSymbolicOperand(MCInst &MI, raw_ostream &cStream,
51                                int64_t Value, uint64_t Address,
52                                bool IsBranch, uint64_t Offset,
53                                uint64_t InstSize) override;
54
55  void tryAddingPcLoadReferenceComment(raw_ostream &cStream,
56                                       int64_t Value,
57                                       uint64_t Address) override;
58  /// @}
59
60  /// \brief Look for an external function symbol at \p Addr.
61  /// (References through the ELF PLT, Mach-O stubs, and similar).
62  /// \returns An MCExpr representing the external symbol, or 0 if not found.
63  virtual StringRef findExternalFunctionAt(uint64_t Addr);
64
65  /// \brief Create an object symbolizer for \p Obj.
66  static MCObjectSymbolizer *
67  createObjectSymbolizer(MCContext &Ctx,
68                         std::unique_ptr<MCRelocationInfo> RelInfo,
69                         const object::ObjectFile *Obj);
70
71private:
72  typedef DenseMap<uint64_t, object::RelocationRef> AddrToRelocMap;
73  typedef std::vector<object::SectionRef> SortedSectionList;
74  SortedSectionList SortedSections;
75  AddrToRelocMap AddrToReloc;
76
77  void buildSectionList();
78  void buildRelocationByAddrMap();
79};
80
81}
82
83#endif
84