IdenticalCodeFolding.h revision a790f0a8f3175183bea088389b3e4ae41813e192
1//===- IdenticalCodeFolding.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_IDENTICALCODEFOLDING_H
10#define MCLD_LD_IDENTICALCODEFOLDING_H
11
12#include <llvm/ADT/MapVector.h>
13#include <string>
14#include <vector>
15
16namespace mcld {
17class Input;
18class LDSection;
19class LinkerConfig;
20class Module;
21class Relocation;
22class TargetLDBackend;
23
24/** \class IdenticalCodeFolding
25 *  \brief Implementation of identical code folding for --icf=[none|all|safe]
26 *  @ref Safe ICF: Pointer Safe and Unwinding Aware Identical Code Folding in
27 *       Gold, http://research.google.com/pubs/pub36912.html
28 */
29class IdenticalCodeFolding {
30public:
31  typedef std::pair<Input*, size_t> ObjectAndId;
32  typedef llvm::MapVector<LDSection*, ObjectAndId> KeptSections;
33
34private:
35  class FoldingCandidate {
36  public:
37    FoldingCandidate()
38        : sect(NULL), reloc_sect(NULL), obj(NULL)
39    { }
40    FoldingCandidate(LDSection* pCode, LDSection* pReloc, Input* pInput)
41        : sect(pCode), reloc_sect(pReloc), obj(pInput)
42    { }
43
44    void initConstantContent(const TargetLDBackend& pBackend,
45        const IdenticalCodeFolding::KeptSections& pKeptSections);
46    std::string getContentWithVariables(const TargetLDBackend& pBackend,
47        const IdenticalCodeFolding::KeptSections& pKeptSections);
48
49    LDSection* sect;
50    LDSection* reloc_sect;
51    Input* obj;
52    std::string content;
53    std::vector<Relocation*> variable_relocs;
54  };
55
56  typedef std::vector<FoldingCandidate> FoldingCandidates;
57
58public:
59  IdenticalCodeFolding(const LinkerConfig& pConfig,
60                       const TargetLDBackend& pBackend,
61                       Module& pModule);
62
63  void foldIdenticalCode();
64
65private:
66  void findCandidates(FoldingCandidates& pCandidateList);
67
68  bool matchCandidates(FoldingCandidates& pCandidateList);
69
70private:
71  const LinkerConfig& m_Config;
72  const TargetLDBackend& m_Backend;
73  Module& m_Module;
74  KeptSections m_KeptSections;
75};
76
77} // namespace of mcld
78
79#endif
80