LLVM  4.0.0
RuntimeDyldELF.h
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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 namespace object {
24 class ELFObjectFileBase;
25 }
26 
28 
29  void resolveRelocation(const SectionEntry &Section, uint64_t Offset,
30  uint64_t Value, uint32_t Type, int64_t Addend,
31  uint64_t SymOffset = 0, SID SectionID = 0);
32 
33  void resolveX86_64Relocation(const SectionEntry &Section, uint64_t Offset,
34  uint64_t Value, uint32_t Type, int64_t Addend,
35  uint64_t SymOffset);
36 
37  void resolveX86Relocation(const SectionEntry &Section, uint64_t Offset,
38  uint32_t Value, uint32_t Type, int32_t Addend);
39 
40  void resolveAArch64Relocation(const SectionEntry &Section, uint64_t Offset,
41  uint64_t Value, uint32_t Type, int64_t Addend);
42 
43  bool resolveAArch64ShortBranch(unsigned SectionID, relocation_iterator RelI,
44  const RelocationValueRef &Value);
45 
46  void resolveARMRelocation(const SectionEntry &Section, uint64_t Offset,
47  uint32_t Value, uint32_t Type, int32_t Addend);
48 
49  void resolvePPC32Relocation(const SectionEntry &Section, uint64_t Offset,
50  uint64_t Value, uint32_t Type, int64_t Addend);
51 
52  void resolvePPC64Relocation(const SectionEntry &Section, uint64_t Offset,
53  uint64_t Value, uint32_t Type, int64_t Addend);
54 
55  void resolveSystemZRelocation(const SectionEntry &Section, uint64_t Offset,
56  uint64_t Value, uint32_t Type, int64_t Addend);
57 
58  unsigned getMaxStubSize() override {
60  return 20; // movz; movk; movk; movk; br
61  if (Arch == Triple::arm || Arch == Triple::thumb)
62  return 8; // 32-bit instruction and 32-bit address
63  else if (IsMipsO32ABI)
64  return 16;
65  else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le)
66  return 44;
67  else if (Arch == Triple::x86_64)
68  return 6; // 2-byte jmp instruction + 32-bit relative address
69  else if (Arch == Triple::systemz)
70  return 16;
71  else
72  return 0;
73  }
74 
75  unsigned getStubAlignment() override {
76  if (Arch == Triple::systemz)
77  return 8;
78  else
79  return 1;
80  }
81 
82  void setMipsABI(const ObjectFile &Obj) override;
83 
84  Error findPPC64TOCSection(const ELFObjectFileBase &Obj,
85  ObjSectionToIDMap &LocalSections,
86  RelocationValueRef &Rel);
87  Error findOPDEntrySection(const ELFObjectFileBase &Obj,
88  ObjSectionToIDMap &LocalSections,
89  RelocationValueRef &Rel);
90 protected:
91  size_t getGOTEntrySize();
92 
93 private:
94  SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }
95 
96  // Allocate no GOT entries for use in the given section.
97  uint64_t allocateGOTEntries(unsigned SectionID, unsigned no);
98 
99  // Resolve the relvative address of GOTOffset in Section ID and place
100  // it at the given Offset
101  void resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset,
102  uint64_t GOTOffset);
103 
104  // For a GOT entry referenced from SectionID, compute a relocation entry
105  // that will place the final resolved value in the GOT slot
106  RelocationEntry computeGOTOffsetRE(unsigned SectionID,
107  uint64_t GOTOffset,
108  uint64_t SymbolOffset,
109  unsigned Type);
110 
111  // Compute the address in memory where we can find the placeholder
112  void *computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const;
113 
114  // Split out common case for createing the RelocationEntry for when the relocation requires
115  // no particular advanced processing.
116  void processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value);
117 
118  // Return matching *LO16 relocation (Mips specific)
119  uint32_t getMatchingLoRelocation(uint32_t RelType,
120  bool IsLocal = false) const;
121 
122  // The tentative ID for the GOT section
123  unsigned GOTSectionID;
124 
125  // Records the current number of allocated slots in the GOT
126  // (This would be equivalent to GOTEntries.size() were it not for relocations
127  // that consume more than one slot)
128  unsigned CurrentGOTIndex;
129 
130 protected:
131  // A map from section to a GOT section that has entries for section's GOT
132  // relocations. (Mips64 specific)
134 
135 private:
136  // A map to avoid duplicate got entries (Mips64 specific)
137  StringMap<uint64_t> GOTSymbolOffsets;
138 
139  // *HI16 relocations will be added for resolving when we find matching
140  // *LO16 part. (Mips specific)
142 
143  // When a module is loaded we save the SectionID of the EH frame section
144  // in a table until we receive a request to register all unregistered
145  // EH frame sections with the memory manager.
146  SmallVector<SID, 2> UnregisteredEHFrameSections;
147  SmallVector<SID, 2> RegisteredEHFrameSections;
148 
149  bool relocationNeedsStub(const RelocationRef &R) const override;
150 
151 public:
154  ~RuntimeDyldELF() override;
155 
156  static std::unique_ptr<RuntimeDyldELF>
159 
160  std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
161  loadObject(const object::ObjectFile &O) override;
162 
163  void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override;
165  processRelocationRef(unsigned SectionID, relocation_iterator RelI,
166  const ObjectFile &Obj,
167  ObjSectionToIDMap &ObjSectionToID,
168  StubMap &Stubs) override;
169  bool isCompatibleFile(const object::ObjectFile &Obj) const override;
170  void registerEHFrames() override;
171  void deregisterEHFrames() override;
172  Error finalizeLoad(const ObjectFile &Obj,
173  ObjSectionToIDMap &SectionMap) override;
174 };
175 
176 } // end namespace llvm
177 
178 #endif
RelocationEntry - used to represent relocations internally in the dynamic linker. ...
RuntimeDyld::MemoryManager & MemMgr
This class is the base class for all object file types.
Definition: ObjectFile.h:178
static std::unique_ptr< RuntimeDyldELF > create(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver)
This is a value type class that represents a single relocation in the list of relocations in the obje...
Definition: ObjectFile.h:41
std::unique_ptr< RuntimeDyld::LoadedObjectInfo > loadObject(const object::ObjectFile &O) override
std::map< RelocationValueRef, uintptr_t > StubMap
Tagged union holding either a T or a Error.
Expected< relocation_iterator > processRelocationRef(unsigned SectionID, relocation_iterator RelI, const ObjectFile &Obj, ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) override
Parses one or more object file relocations (some object files use relocation pairs) and stores it to ...
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
void registerEHFrames() override
uint32_t Offset
Symbol resolution.
Definition: JITSymbol.h:165
bool isCompatibleFile(const object::ObjectFile &Obj) const override
DenseMap< SID, SID > SectionToGOTMap
void deregisterEHFrames() override
Error finalizeLoad(const ObjectFile &Obj, ObjSectionToIDMap &SectionMap) override
This is a 'vector' (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:843
JITSymbolResolver & Resolver
Triple::ArchType Arch
std::map< SectionRef, unsigned > ObjSectionToIDMap
SectionEntry - represents a section emitted into memory by the dynamic linker.
RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr, JITSymbolResolver &Resolver)
LLVM Value Representation.
Definition: Value.h:71
Lightweight error class with error context and mandatory checking.