1 //===-  X86Relocator.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_X86_X86RELOCATOR_H_
10 #define TARGET_X86_X86RELOCATOR_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 "X86LDBackend.h"
17 
18 namespace mcld {
19 
20 class LinkerConfig;
21 class ResolveInfo;
22 
23 /** \class X86Relocator
24  *  \brief X86Relocator creates and destroys the X86 relocations.
25  *
26  */
27 class X86Relocator : public Relocator {
28  public:
29   typedef KeyEntryMap<ResolveInfo, PLTEntryBase> SymPLTMap;
30 
31   /** \enum ReservedEntryType
32    *  \brief The reserved entry type of reserved space in ResolveInfo.
33    *
34    *  This is used for sacnRelocation to record what kinds of entries are
35    *  reserved for this resolved symbol. In X86, there are three kinds of
36    *  entries, GOT, PLT, and dynamic reloction.
37    *
38    *  bit:  3     2     1     0
39    *   |    | PLT | GOT | Rel |
40    *
41    *  value    Name         - Description
42    *
43    *  0000     None         - no reserved entry
44    *  0001     ReserveRel   - reserve an dynamic relocation entry
45    *  0010     ReserveGOT   - reserve an GOT entry
46    *  0100     ReservePLT   - reserve an PLT entry and the corresponding GOT,
47    *
48    */
49   enum ReservedEntryType {
50     None = 0,
51     ReserveRel = 1,
52     ReserveGOT = 2,
53     ReservePLT = 4,
54   };
55 
56   /** \enum EntryValue
57    *  \brief The value of the entries. The symbol value will be decided at after
58    *  layout, so we mark the entry during scanRelocation and fill up the actual
59    *  value when applying relocations.
60    */
61   enum EntryValue { Default = 0, SymVal = 1 };
62 
63  public:
64   explicit X86Relocator(const LinkerConfig& pConfig);
65   ~X86Relocator();
66 
67   virtual Result applyRelocation(Relocation& pRelocation) = 0;
68 
69   virtual const char* getName(Relocation::Type pType) const = 0;
70 
getSymPLTMap()71   const SymPLTMap& getSymPLTMap() const { return m_SymPLTMap; }
getSymPLTMap()72   SymPLTMap& getSymPLTMap() { return m_SymPLTMap; }
73 
74   /// scanRelocation - determine the empty entries are needed or not and create
75   /// the empty entries if needed.
76   /// For X86, following entries are check to create:
77   /// - GOT entry (for .got and .got.plt sections)
78   /// - PLT entry (for .plt section)
79   /// - dynamin relocation entries (for .rel.plt and .rel.dyn sections)
80   void scanRelocation(Relocation& pReloc,
81                       IRBuilder& pBuilder,
82                       Module& pModule,
83                       LDSection& pSection,
84                       Input& pInput);
85 
86  protected:
87   /// addCopyReloc - add a copy relocation into .rel.dyn for pSym
88   /// @param pSym - A resolved copy symbol that defined in BSS section
89   void addCopyReloc(ResolveInfo& pSym, X86GNULDBackend& pTarget);
90 
91   /// defineSymbolforCopyReloc - allocate a space in BSS section and
92   /// and force define the copy of pSym to BSS section
93   /// @return the output LDSymbol of the copy symbol
94   LDSymbol& defineSymbolforCopyReloc(IRBuilder& pLinker,
95                                      const ResolveInfo& pSym,
96                                      X86GNULDBackend& pTarget);
97 
98  private:
99   virtual void scanLocalReloc(Relocation& pReloc,
100                               IRBuilder& pBuilder,
101                               Module& pModule,
102                               LDSection& pSection) = 0;
103 
104   virtual void scanGlobalReloc(Relocation& pReloc,
105                                IRBuilder& pBuilder,
106                                Module& pModule,
107                                LDSection& pSection) = 0;
108 
109  private:
110   SymPLTMap m_SymPLTMap;
111 };
112 
113 /** \class X86_32Relocator
114  *  \brief X86_32Relocator creates and destroys the X86-32 relocations.
115  *
116  */
117 class X86_32Relocator : public X86Relocator {
118  public:
119   typedef KeyEntryMap<ResolveInfo, X86_32GOTEntry> SymGOTMap;
120   typedef KeyEntryMap<ResolveInfo, X86_32GOTEntry> SymGOTPLTMap;
121 
122   enum {
123     R_386_TLS_OPT = 44  // mcld internal relocation type
124   };
125 
126  public:
127   X86_32Relocator(X86_32GNULDBackend& pParent, const LinkerConfig& pConfig);
128 
129   Result applyRelocation(Relocation& pRelocation);
130 
getTarget()131   X86_32GNULDBackend& getTarget() { return m_Target; }
132 
getTarget()133   const X86_32GNULDBackend& getTarget() const { return m_Target; }
134 
135   const char* getName(Relocation::Type pType) const;
136 
137   Size getSize(Relocation::Type pType) const;
138 
getSymGOTMap()139   const SymGOTMap& getSymGOTMap() const { return m_SymGOTMap; }
getSymGOTMap()140   SymGOTMap& getSymGOTMap() { return m_SymGOTMap; }
141 
getSymGOTPLTMap()142   const SymGOTPLTMap& getSymGOTPLTMap() const { return m_SymGOTPLTMap; }
getSymGOTPLTMap()143   SymGOTPLTMap& getSymGOTPLTMap() { return m_SymGOTPLTMap; }
144 
145   X86_32GOTEntry& getTLSModuleID();
146 
147   /// mayHaveFunctionPointerAccess - check if the given reloc would possibly
148   /// access a function pointer.
149   virtual bool mayHaveFunctionPointerAccess(const Relocation& pReloc) const;
150 
151   /// getDebugStringOffset - get the offset from the relocation target. This is
152   /// used to get the debug string offset.
153   uint32_t getDebugStringOffset(Relocation& pReloc) const;
154 
155   /// applyDebugStringOffset - apply the relocation target to specific offset.
156   /// This is used to set the debug string offset.
157   void applyDebugStringOffset(Relocation& pReloc, uint32_t pOffset);
158 
159  private:
160   void scanLocalReloc(Relocation& pReloc,
161                       IRBuilder& pBuilder,
162                       Module& pModule,
163                       LDSection& pSection);
164 
165   void scanGlobalReloc(Relocation& pReloc,
166                        IRBuilder& pBuilder,
167                        Module& pModule,
168                        LDSection& pSection);
169 
170   /// -----  tls optimization  ----- ///
171   /// convert R_386_TLS_IE to R_386_TLS_LE
172   void convertTLSIEtoLE(Relocation& pReloc, LDSection& pSection);
173 
174  private:
175   X86_32GNULDBackend& m_Target;
176   SymGOTMap m_SymGOTMap;
177   SymGOTPLTMap m_SymGOTPLTMap;
178 };
179 
180 /** \class X86_64Relocator
181  *  \brief X86_64Relocator creates and destroys the X86-64 relocations.
182  *
183  */
184 class X86_64Relocator : public X86Relocator {
185  public:
186   typedef KeyEntryMap<ResolveInfo, X86_64GOTEntry> SymGOTMap;
187   typedef KeyEntryMap<ResolveInfo, X86_64GOTEntry> SymGOTPLTMap;
188   typedef KeyEntryMap<Relocation, Relocation> RelRelMap;
189 
190  public:
191   X86_64Relocator(X86_64GNULDBackend& pParent, const LinkerConfig& pConfig);
192 
193   Result applyRelocation(Relocation& pRelocation);
194 
getTarget()195   X86_64GNULDBackend& getTarget() { return m_Target; }
196 
getTarget()197   const X86_64GNULDBackend& getTarget() const { return m_Target; }
198 
199   const char* getName(Relocation::Type pType) const;
200 
201   Size getSize(Relocation::Type pType) const;
202 
getSymGOTMap()203   const SymGOTMap& getSymGOTMap() const { return m_SymGOTMap; }
getSymGOTMap()204   SymGOTMap& getSymGOTMap() { return m_SymGOTMap; }
205 
getSymGOTPLTMap()206   const SymGOTPLTMap& getSymGOTPLTMap() const { return m_SymGOTPLTMap; }
getSymGOTPLTMap()207   SymGOTPLTMap& getSymGOTPLTMap() { return m_SymGOTPLTMap; }
208 
getRelRelMap()209   const RelRelMap& getRelRelMap() const { return m_RelRelMap; }
getRelRelMap()210   RelRelMap& getRelRelMap() { return m_RelRelMap; }
211 
212   /// mayHaveFunctionPointerAccess - check if the given reloc would possibly
213   /// access a function pointer.
214   virtual bool mayHaveFunctionPointerAccess(const Relocation& pReloc) const;
215 
216   /// getDebugStringOffset - get the offset from the relocation target. This is
217   /// used to get the debug string offset.
218   uint32_t getDebugStringOffset(Relocation& pReloc) const;
219 
220   /// applyDebugStringOffset - apply the relocation target to specific offset.
221   /// This is used to set the debug string offset.
222   void applyDebugStringOffset(Relocation& pReloc, uint32_t pOffset);
223 
224  private:
225   void scanLocalReloc(Relocation& pReloc,
226                       IRBuilder& pBuilder,
227                       Module& pModule,
228                       LDSection& pSection);
229 
230   void scanGlobalReloc(Relocation& pReloc,
231                        IRBuilder& pBuilder,
232                        Module& pModule,
233                        LDSection& pSection);
234 
235  private:
236   X86_64GNULDBackend& m_Target;
237   SymGOTMap m_SymGOTMap;
238   SymGOTPLTMap m_SymGOTPLTMap;
239   RelRelMap m_RelRelMap;
240 };
241 
242 }  // namespace mcld
243 
244 #endif  // TARGET_X86_X86RELOCATOR_H_
245