TargetLDBackend.h revision 5460a1f25d9ddecb5c70667267d66d51af177a99 
1//===-- llvm/Target/TargetLDBackend.h - Target LD Backend -----*- C++ -*-===//
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 LLVM_TARGET_TARGETLDBACKEND_H
10#define LLVM_TARGET_TARGETLDBACKEND_H
11
12#include <llvm/Support/DataTypes.h>
13#include <mcld/MC/MCLDOutput.h>
14
15namespace mcld {
16
17class MCLinker;
18class Relocation;
19class RelocationFactory;
20class Layout;
21class ArchiveReader;
22class ObjectReader;
23class DynObjReader;
24class ObjectWriter;
25class DynObjWriter;
26class LDContext;
27class SectionMap;
28class Output;
29class MCLDInfo;
30class SymbolCategory;
31class Input;
32class LDFileFormat;
33class GOT;
34
35//===----------------------------------------------------------------------===//
36/// TargetLDBackend - Generic interface to target specific assembler backends.
37///
38class TargetLDBackend
39{
40  TargetLDBackend(const TargetLDBackend &);   // DO NOT IMPLEMENT
41  void operator=(const TargetLDBackend &);  // DO NOT IMPLEMENT
42
43protected:
44  TargetLDBackend();
45
46public:
47  virtual ~TargetLDBackend();
48
49  // -----  target dependent  ----- //
50  virtual bool initTargetSectionMap(SectionMap& pSectionMap) { return true;}
51  virtual void initTargetSegments(MCLinker& pLinker) { }
52  virtual void initTargetSections(MCLinker& pLinker) { }
53  virtual void initTargetSymbols(MCLinker& pLinker) { }
54  virtual void initTargetRelocation(MCLinker& pLinker) { }
55  virtual bool initStandardSymbols(MCLinker& pLinker) = 0;
56  virtual bool initRelocFactory(const MCLinker& pLinker) = 0;
57
58  virtual RelocationFactory* getRelocFactory() = 0;
59
60  /// scanRelocation - When read in relocations, backend can do any modification
61  /// to relocation and generate empty entries, such as GOT, dynamic relocation
62  /// entries and other target dependent entries. These entries are generated
63  /// for layout to adjust the ouput offset.
64  /// @param pReloc - a read in relocation entry
65  /// @param pInputSym - the input LDSymbol of relocation target symbol
66  /// @param pOutput - the ouput file
67  virtual void scanRelocation(Relocation& pReloc,
68                              const LDSymbol& pInputSym,
69                              MCLinker& pLinker,
70                              const MCLDInfo& pLDInfo,
71                              const Output& pOutput) = 0;
72
73  // -----  format dependent  ----- //
74  virtual bool initArchiveReader(MCLinker&, MCLDInfo&) = 0;
75  virtual bool initObjectReader(MCLinker&) = 0;
76  virtual bool initDynObjReader(MCLinker&) = 0;
77  virtual bool initObjectWriter(MCLinker&) = 0;
78  virtual bool initDynObjWriter(MCLinker&) = 0;
79
80  virtual bool initExecSections(MCLinker&) = 0;
81  virtual bool initDynObjSections(MCLinker&) = 0;
82
83  virtual ArchiveReader *getArchiveReader() = 0;
84  virtual ObjectReader *getObjectReader() = 0;
85  virtual DynObjReader *getDynObjReader() = 0;
86  virtual ObjectWriter *getObjectWriter() = 0;
87  virtual DynObjWriter *getDynObjWriter() = 0;
88
89  virtual LDFileFormat* getDynObjFileFormat() = 0;
90  virtual LDFileFormat* getExecFileFormat() = 0;
91
92  /// preLayout - Backend can do any needed modification before layout
93  virtual void preLayout(const Output& pOutput,
94                         const MCLDInfo& pInfo,
95                         MCLinker& pLinker) = 0;
96
97  /// postLayout -Backend can do any needed modification after layout
98  virtual void postLayout(const Output& pOutput,
99                          const MCLDInfo& pInfo,
100                          MCLinker& pLinker) = 0;
101
102  /// Is the target machine little endian? **/
103  virtual bool isLittleEndian() const = 0;
104
105  /// bit class. the bit length of the target machine, 32 or 64 **/
106  virtual unsigned int bitclass() const = 0;
107
108  /// the page size of the target machine
109  virtual unsigned int pagesize() const = 0;
110
111  /// section start offset in the output file
112  virtual size_t sectionStartOffset() const = 0;
113
114  /// computeSectionOrder - compute the layout order of the given section
115  virtual unsigned int getSectionOrder(const Output& pOutput,
116                                       const LDSection& pSectHdr) const = 0;
117
118  /// sizeNamePools - compute the size of regular name pools
119  /// In ELF executable files, regular name pools are .symtab, .strtab.,
120  /// .dynsym, .dynstr, and .hash
121  virtual void
122  sizeNamePools(const Output& pOutput,
123                const SymbolCategory& pSymbols,
124                const MCLDInfo& pLDInfo) = 0;
125
126  /// finalizeSymbol - Linker checks pSymbol.reserved() if it's not zero,
127  /// then it will ask backend to finalize the symbol value.
128  /// @return ture - if backend set the symbol value sucessfully
129  /// @return false - if backend do not recognize the symbol
130  virtual bool finalizeSymbol(LDSymbol& pSymbol) const = 0;
131
132  /// allocateCommonSymbols - allocate common symbols in the corresponding
133  /// sections.
134  virtual bool allocateCommonSymbols(const MCLDInfo& pLDInfo, MCLinker& pLinker) const = 0;
135
136  /// readSection - read a target dependent section
137  virtual bool readSection(Input& pInput,
138                           MCLinker& pLinker,
139                           LDSection& pInputSectHdr)
140  { return true; }
141
142};
143
144} // End mcld namespace
145
146#endif
147