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1 //===-  HexagonRelocator.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 TARGET_HEXAGON_HEXAGONRELOCATOR_H_
10 #define TARGET_HEXAGON_HEXAGONRELOCATOR_H_
11 
12 #include "mcld/LD/Relocator.h"
13 #include "mcld/Target/GOT.h"
14 #include "mcld/Target/PLT.h"
15 #include "mcld/Target/KeyEntryMap.h"
16 #include "HexagonLDBackend.h"
17 
18 namespace mcld {
19 
20 class LinkerConfig;
21 class ResolveInfo;
22 
23 /** \class HexagonRelocator
24  *  \brief HexagonRelocator creates and destroys the Hexagon relocations.
25  *
26  */
27 class HexagonRelocator : public Relocator {
28  public:
29   typedef KeyEntryMap<ResolveInfo, PLTEntryBase> SymPLTMap;
30   typedef KeyEntryMap<ResolveInfo, HexagonGOTEntry> SymGOTMap;
31   typedef KeyEntryMap<ResolveInfo, HexagonGOTEntry> SymGOTPLTMap;
32   typedef KeyEntryMap<Relocation, Relocation> RelRelMap;
33 
34  public:
35   /** \enum ReservedEntryType
36    *  \brief The reserved entry type of reserved space in ResolveInfo.
37    *
38    *  This is used for sacnRelocation to record what kinds of entries are
39    *  reserved for this resolved symbol. In Hexagon, there are three kinds
40    *  of entries, GOT, PLT, and dynamic relocation.
41    *
42    *  bit:  3     2     1     0
43    *   |    | PLT | GOT | Rel |
44    *
45    *  value    Name         - Description
46    *
47    *  0000     None         - no reserved entry
48    *  0001     ReserveRel   - reserve an dynamic relocation entry
49    *  0010     ReserveGOT   - reserve an GOT entry
50    *  0100     ReservePLT   - reserve an PLT entry and the corresponding GOT,
51    *
52    */
53   enum ReservedEntryType {
54     None = 0,
55     ReserveRel = 1,
56     ReserveGOT = 2,
57     ReservePLT = 4,
58   };
59 
60   /** \enum EntryValue
61    *  \brief The value of the entries. The symbol value will be decided at after
62    *  layout, so we mark the entry during scanRelocation and fill up the actual
63    *  value when applying relocations.
64    */
65   enum EntryValue { Default = 0, SymVal = 1 };
66 
67   HexagonRelocator(HexagonLDBackend& pParent, const LinkerConfig& pConfig);
68   ~HexagonRelocator();
69 
70   Result applyRelocation(Relocation& pRelocation);
71 
72   /// scanRelocation - determine the empty entries are needed or not and create
73   /// the empty entries if needed.
74   /// For Hexagon, following entries are check to create:
75   /// - GOT entry (for .got and .got.plt sections)
76   /// - PLT entry (for .plt section)
77   /// - dynamin relocation entries (for .rel.plt and .rel.dyn sections)
78   void scanRelocation(Relocation& pReloc,
79                       IRBuilder& pBuilder,
80                       Module& pModule,
81                       LDSection& pSection,
82                       Input& pInput);
83 
84   // Handle partial linking
85   void partialScanRelocation(Relocation& pReloc,
86                              Module& pModule);
87 
getTarget()88   HexagonLDBackend& getTarget() { return m_Target; }
89 
getTarget()90   const HexagonLDBackend& getTarget() const { return m_Target; }
91 
92   const char* getName(Relocation::Type pType) const;
93 
94   Size getSize(Relocation::Type pType) const;
95 
getSymPLTMap()96   const SymPLTMap& getSymPLTMap() const { return m_SymPLTMap; }
getSymPLTMap()97   SymPLTMap& getSymPLTMap() { return m_SymPLTMap; }
98 
getSymGOTMap()99   const SymGOTMap& getSymGOTMap() const { return m_SymGOTMap; }
getSymGOTMap()100   SymGOTMap& getSymGOTMap() { return m_SymGOTMap; }
101 
getSymGOTPLTMap()102   const SymGOTPLTMap& getSymGOTPLTMap() const { return m_SymGOTPLTMap; }
getSymGOTPLTMap()103   SymGOTPLTMap& getSymGOTPLTMap() { return m_SymGOTPLTMap; }
104 
getRelRelMap()105   const RelRelMap& getRelRelMap() const { return m_RelRelMap; }
getRelRelMap()106   RelRelMap& getRelRelMap() { return m_RelRelMap; }
107 
108   /// getDebugStringOffset - get the offset from the relocation target. This is
109   /// used to get the debug string offset.
getDebugStringOffset(Relocation & pReloc)110   uint32_t getDebugStringOffset(Relocation& pReloc) const { return 0; }
111 
112   /// applyDebugStringOffset - apply the relocation target to specific offset.
113   /// This is used to set the debug string offset.
applyDebugStringOffset(Relocation & pReloc,uint32_t pOffset)114   void applyDebugStringOffset(Relocation& pReloc, uint32_t pOffset) {}
115 
116  protected:
117   /// addCopyReloc - add a copy relocation into .rela.dyn for pSym
118   /// @param pSym - A resolved copy symbol that defined in BSS section
119   void addCopyReloc(ResolveInfo& pSym, HexagonLDBackend& pTarget);
120 
121   /// defineSymbolforCopyReloc - allocate a space in BSS section and
122   /// and force define the copy of pSym to BSS section
123   /// @return the output LDSymbol of the copy symbol
124   LDSymbol& defineSymbolforCopyReloc(IRBuilder& pLinker,
125                                      const ResolveInfo& pSym,
126                                      HexagonLDBackend& pTarget);
127 
128  private:
129   virtual void scanLocalReloc(Relocation& pReloc,
130                               IRBuilder& pBuilder,
131                               Module& pModule,
132                               LDSection& pSection);
133 
134   virtual void scanGlobalReloc(Relocation& pReloc,
135                                IRBuilder& pBuilder,
136                                Module& pModule,
137                                LDSection& pSection);
138 
139   HexagonLDBackend& m_Target;
140   SymPLTMap m_SymPLTMap;
141   SymGOTMap m_SymGOTMap;
142   SymGOTPLTMap m_SymGOTPLTMap;
143   RelRelMap m_RelRelMap;
144 };
145 
146 }  // namespace mcld
147 
148 #endif  // TARGET_HEXAGON_HEXAGONRELOCATOR_H_
149