1 //===-- RuntimeDyldELF.h - Run-time dynamic linker for MC-JIT ---*- 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 // ELF support for MC-JIT runtime dynamic linker.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H
15 #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H
16 
17 #include "RuntimeDyldImpl.h"
18 #include "llvm/ADT/DenseMap.h"
19 
20 using namespace llvm;
21 
22 namespace llvm {
23 
24 class RuntimeDyldELF : public RuntimeDyldImpl {
25 
26   void resolveRelocation(const SectionEntry &Section, uint64_t Offset,
27                          uint64_t Value, uint32_t Type, int64_t Addend,
28                          uint64_t SymOffset = 0);
29 
30   void resolveX86_64Relocation(const SectionEntry &Section, uint64_t Offset,
31                                uint64_t Value, uint32_t Type, int64_t Addend,
32                                uint64_t SymOffset);
33 
34   void resolveX86Relocation(const SectionEntry &Section, uint64_t Offset,
35                             uint32_t Value, uint32_t Type, int32_t Addend);
36 
37   void resolveAArch64Relocation(const SectionEntry &Section, uint64_t Offset,
38                                 uint64_t Value, uint32_t Type, int64_t Addend);
39 
40   void resolveARMRelocation(const SectionEntry &Section, uint64_t Offset,
41                             uint32_t Value, uint32_t Type, int32_t Addend);
42 
43   void resolveMIPSRelocation(const SectionEntry &Section, uint64_t Offset,
44                              uint32_t Value, uint32_t Type, int32_t Addend);
45 
46   void resolvePPC64Relocation(const SectionEntry &Section, uint64_t Offset,
47                               uint64_t Value, uint32_t Type, int64_t Addend);
48 
49   void resolveSystemZRelocation(const SectionEntry &Section, uint64_t Offset,
50                                 uint64_t Value, uint32_t Type, int64_t Addend);
51 
getMaxStubSize()52   unsigned getMaxStubSize() override {
53     if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be)
54       return 20; // movz; movk; movk; movk; br
55     if (Arch == Triple::arm || Arch == Triple::thumb)
56       return 8; // 32-bit instruction and 32-bit address
57     else if (Arch == Triple::mipsel || Arch == Triple::mips)
58       return 16;
59     else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le)
60       return 44;
61     else if (Arch == Triple::x86_64)
62       return 6; // 2-byte jmp instruction + 32-bit relative address
63     else if (Arch == Triple::systemz)
64       return 16;
65     else
66       return 0;
67   }
68 
getStubAlignment()69   unsigned getStubAlignment() override {
70     if (Arch == Triple::systemz)
71       return 8;
72     else
73       return 1;
74   }
75 
76   void findPPC64TOCSection(const ObjectFile &Obj,
77                            ObjSectionToIDMap &LocalSections,
78                            RelocationValueRef &Rel);
79   void findOPDEntrySection(const ObjectFile &Obj,
80                            ObjSectionToIDMap &LocalSections,
81                            RelocationValueRef &Rel);
82 
83   size_t getGOTEntrySize();
84 
getSection(unsigned SectionID)85   SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }
86 
87   // Allocate no GOT entries for use in the given section.
88   uint64_t allocateGOTEntries(unsigned SectionID, unsigned no);
89 
90   // Resolve the relvative address of GOTOffset in Section ID and place
91   // it at the given Offset
92   void resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset,
93                                   uint64_t GOTOffset);
94 
95   // For a GOT entry referenced from SectionID, compute a relocation entry
96   // that will place the final resolved value in the GOT slot
97   RelocationEntry computeGOTOffsetRE(unsigned SectionID,
98                                      uint64_t GOTOffset,
99                                      uint64_t SymbolOffset,
100                                      unsigned Type);
101 
102   // The tentative ID for the GOT section
103   unsigned GOTSectionID;
104 
105   // Records the current number of allocated slots in the GOT
106   // (This would be equivalent to GOTEntries.size() were it not for relocations
107   // that consume more than one slot)
108   unsigned CurrentGOTIndex;
109 
110   // When a module is loaded we save the SectionID of the EH frame section
111   // in a table until we receive a request to register all unregistered
112   // EH frame sections with the memory manager.
113   SmallVector<SID, 2> UnregisteredEHFrameSections;
114   SmallVector<SID, 2> RegisteredEHFrameSections;
115 
116 public:
117   RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr,
118                  RuntimeDyld::SymbolResolver &Resolver);
119   ~RuntimeDyldELF() override;
120 
121   std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
122   loadObject(const object::ObjectFile &O) override;
123 
124   void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override;
125   relocation_iterator
126   processRelocationRef(unsigned SectionID, relocation_iterator RelI,
127                        const ObjectFile &Obj,
128                        ObjSectionToIDMap &ObjSectionToID,
129                        StubMap &Stubs) override;
130   bool isCompatibleFile(const object::ObjectFile &Obj) const override;
131   void registerEHFrames() override;
132   void deregisterEHFrames() override;
133   void finalizeLoad(const ObjectFile &Obj,
134                     ObjSectionToIDMap &SectionMap) override;
135 };
136 
137 } // end namespace llvm
138 
139 #endif
140