MCSymbolizer.h revision 2c94d0faa0e1c268893d5e04dc77e8a35889db00 
1//===-- llvm/MC/MCSymbolizer.h - MCSymbolizer class -------------*- 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// This file contains the declaration of the MCSymbolizer class, which is used
11// to symbolize instructions decoded from an object, that is, transform their
12// immediate operands to MCExprs.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_MC_MCSYMBOLIZER_H
17#define LLVM_MC_MCSYMBOLIZER_H
18
19#include "llvm/ADT/OwningPtr.h"
20#include "llvm/MC/MCRelocationInfo.h"
21#include "llvm/Support/Compiler.h"
22#include "llvm/Support/DataTypes.h"
23
24namespace llvm {
25
26class MCContext;
27class MCInst;
28class raw_ostream;
29
30/// \brief Symbolize and annotate disassembled instructions.
31///
32/// For now this mimics the old symbolization logic (from both ARM and x86), that
33/// relied on user-provided (C API) callbacks to do the actual symbol lookup in
34/// the object file. This was moved to MCExternalSymbolizer.
35/// A better API would not rely on actually calling the two methods here from
36/// inside each disassembler, but would use the instr info to determine what
37/// operands are actually symbolizable, and in what way. I don't think this
38/// information exists right now.
39class MCSymbolizer {
40  MCSymbolizer(const MCSymbolizer &) LLVM_DELETED_FUNCTION;
41  void operator=(const MCSymbolizer &) LLVM_DELETED_FUNCTION;
42
43protected:
44  MCContext &Ctx;
45  OwningPtr<MCRelocationInfo> RelInfo;
46
47public:
48  /// \brief Construct an MCSymbolizer, taking ownership of \p RelInfo.
49  MCSymbolizer(MCContext &Ctx, OwningPtr<MCRelocationInfo> &RelInfo);
50  virtual ~MCSymbolizer();
51
52  /// \brief Try to add a symbolic operand instead of \p Value to the MCInst.
53  ///
54  /// Instead of having a difficult to read immediate, a symbolic operand would
55  /// represent this immediate in a more understandable way, for instance as a
56  /// symbol or an offset from a symbol. Relocations can also be used to enrich
57  /// the symbolic expression.
58  /// @param Inst      - The MCInst where to insert the symbolic operand.
59  /// @param cStream   - Stream to print comments and annotations on.
60  /// @param Value     - Operand value, pc-adjusted by the caller if necessary.
61  /// @param Address   - Load address of the instruction.
62  /// @param IsBranch  - Is the instruction a branch?
63  /// @param Offset    - Byte offset of the operand inside the inst.
64  /// @param InstSize  - Size of the instruction in bytes.
65  /// @return Whether a symbolic operand was added.
66  virtual bool tryAddingSymbolicOperand(MCInst &Inst, raw_ostream &cStream,
67                                        int64_t Value, uint64_t Address,
68                                        bool IsBranch, uint64_t Offset,
69                                        uint64_t InstSize) = 0;
70
71  /// \brief Try to add a comment on the PC-relative load.
72  /// For instance, in Mach-O, this is used to add annotations to instructions
73  /// that use C string literals, as found in __cstring.
74  virtual void tryAddingPcLoadReferenceComment(raw_ostream &cStream,
75                                               int64_t Value,
76                                               uint64_t Address) = 0;
77};
78
79}
80
81#endif
82