1//===-- RuntimeDyldELF.h - Run-time dynamic linker for MC-JIT ---*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// ELF support for MC-JIT runtime dynamic linker.
10//
11//===----------------------------------------------------------------------===//
12
13#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H
14#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H
15
16#include "RuntimeDyldImpl.h"
17#include "llvm/ADT/DenseMap.h"
18
19namespace llvm {
20namespace object {
21class ELFObjectFileBase;
22}
23
24class 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, SID SectionID = 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 bool resolveAArch64ShortBranch(unsigned SectionID, relocation_iterator RelI,
41 const RelocationValueRef &Value);
42
43 void resolveAArch64Branch(unsigned SectionID, const RelocationValueRef &Value,
44 relocation_iterator RelI, StubMap &Stubs);
45
46 void resolveARMRelocation(const SectionEntry &Section, uint64_t Offset,
47 uint32_t Value, uint32_t Type, int32_t Addend);
48
49 void resolveLoongArch64Relocation(const SectionEntry &Section,
50 uint64_t Offset, uint64_t Value,
51 uint32_t Type, int64_t Addend);
52
53 bool resolveLoongArch64ShortBranch(unsigned SectionID,
54 relocation_iterator RelI,
55 const RelocationValueRef &Value);
56
57 void resolveLoongArch64Branch(unsigned SectionID,
58 const RelocationValueRef &Value,
59 relocation_iterator RelI, StubMap &Stubs);
60
61 void resolvePPC32Relocation(const SectionEntry &Section, uint64_t Offset,
62 uint64_t Value, uint32_t Type, int64_t Addend);
63
64 void resolvePPC64Relocation(const SectionEntry &Section, uint64_t Offset,
65 uint64_t Value, uint32_t Type, int64_t Addend);
66
67 void resolveSystemZRelocation(const SectionEntry &Section, uint64_t Offset,
68 uint64_t Value, uint32_t Type, int64_t Addend);
69
70 void resolveBPFRelocation(const SectionEntry &Section, uint64_t Offset,
71 uint64_t Value, uint32_t Type, int64_t Addend);
72
73 void resolveRISCVRelocation(const SectionEntry &Section, uint64_t Offset,
74 uint64_t Value, uint32_t Type, int64_t Addend,
75 SID SectionID);
76
77 unsigned getMaxStubSize() const override {
78 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be)
79 return 20; // movz; movk; movk; movk; br
80 if (Arch == Triple::arm || Arch == Triple::thumb)
81 return 8; // 32-bit instruction and 32-bit address
82 else if (IsMipsO32ABI || IsMipsN32ABI)
83 return 16;
84 else if (IsMipsN64ABI)
85 return 32;
86 if (Arch == Triple::loongarch64)
87 return 20; // lu12i.w; ori; lu32i.d; lu52i.d; jr
88 else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le)
89 return 44;
90 else if (Arch == Triple::x86_64)
91 return 6; // 2-byte jmp instruction + 32-bit relative address
92 else if (Arch == Triple::systemz)
93 return 16;
94 else
95 return 0;
96 }
97
98 Align getStubAlignment() override {
99 if (Arch == Triple::systemz)
100 return Align(8);
101 else
102 return Align(1);
103 }
104
105 void setMipsABI(const ObjectFile &Obj) override;
106
107 Error findPPC64TOCSection(const object::ELFObjectFileBase &Obj,
108 ObjSectionToIDMap &LocalSections,
109 RelocationValueRef &Rel);
110 Error findOPDEntrySection(const object::ELFObjectFileBase &Obj,
111 ObjSectionToIDMap &LocalSections,
112 RelocationValueRef &Rel);
113
114protected:
115 size_t getGOTEntrySize() override;
116
117private:
118 SectionEntry &getSection(unsigned SectionID) { return Sections[SectionID]; }
119
120 // Allocate no GOT entries for use in the given section.
121 uint64_t allocateGOTEntries(unsigned no);
122
123 // Find GOT entry corresponding to relocation or create new one.
124 uint64_t findOrAllocGOTEntry(const RelocationValueRef &Value,
125 unsigned GOTRelType);
126
127 // Resolve the relative address of GOTOffset in Section ID and place
128 // it at the given Offset
129 void resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset,
130 uint64_t GOTOffset, uint32_t Type);
131
132 // For a GOT entry referenced from SectionID, compute a relocation entry
133 // that will place the final resolved value in the GOT slot
134 RelocationEntry computeGOTOffsetRE(uint64_t GOTOffset, uint64_t SymbolOffset,
135 unsigned Type);
136
137 // Compute the address in memory where we can find the placeholder
138 void *computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const;
139
140 // Split out common case for creating the RelocationEntry for when the
141 // relocation requires no particular advanced processing.
142 void processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value);
143
144 // Return matching *LO16 relocation (Mips specific)
145 uint32_t getMatchingLoRelocation(uint32_t RelType,
146 bool IsLocal = false) const;
147
148 // The tentative ID for the GOT section
149 unsigned GOTSectionID;
150
151 // Records the current number of allocated slots in the GOT
152 // (This would be equivalent to GOTEntries.size() were it not for relocations
153 // that consume more than one slot)
154 unsigned CurrentGOTIndex;
155
156protected:
157 // A map from section to a GOT section that has entries for section's GOT
158 // relocations. (Mips64 specific)
159 DenseMap<SID, SID> SectionToGOTMap;
160
161private:
162 // A map to avoid duplicate got entries (Mips64 specific)
163 StringMap<uint64_t> GOTSymbolOffsets;
164
165 // *HI16 relocations will be added for resolving when we find matching
166 // *LO16 part. (Mips specific)
167 //
168 // *HI20 relocations will be added for resolving when we find matching
169 // *LO12 part. (RISC-V specific)
170 SmallVector<std::pair<RelocationValueRef, RelocationEntry>, 8> PendingRelocs;
171
172 // When a module is loaded we save the SectionID of the EH frame section
173 // in a table until we receive a request to register all unregistered
174 // EH frame sections with the memory manager.
175 SmallVector<SID, 2> UnregisteredEHFrameSections;
176
177 // Map between GOT relocation value and corresponding GOT offset
178 std::map<RelocationValueRef, uint64_t> GOTOffsetMap;
179
180 /// The ID of the current IFunc stub section
181 unsigned IFuncStubSectionID = 0;
182 /// The current offset into the IFunc stub section
183 uint64_t IFuncStubOffset = 0;
184
185 /// A IFunc stub and its original symbol
186 struct IFuncStub {
187 /// The offset of this stub in the IFunc stub section
188 uint64_t StubOffset;
189 /// The symbol table entry of the original symbol
190 SymbolTableEntry OriginalSymbol;
191 };
192
193 /// The IFunc stubs
194 SmallVector<IFuncStub, 2> IFuncStubs;
195
196 /// Create the code for the IFunc resolver at the given address. This code
197 /// works together with the stubs created in createIFuncStub() to call the
198 /// resolver function and then jump to the real function address.
199 /// It must not be larger than 64B.
200 void createIFuncResolver(uint8_t *Addr) const;
201 /// Create the code for an IFunc stub for the IFunc that is defined in
202 /// section IFuncSectionID at offset IFuncOffset. The IFunc resolver created
203 /// by createIFuncResolver() is defined in the section IFuncStubSectionID at
204 /// offset IFuncResolverOffset. The code should be written into the section
205 /// with the id IFuncStubSectionID at the offset IFuncStubOffset.
206 void createIFuncStub(unsigned IFuncStubSectionID,
207 uint64_t IFuncResolverOffset, uint64_t IFuncStubOffset,
208 unsigned IFuncSectionID, uint64_t IFuncOffset);
209 /// Return the maximum size of a stub created by createIFuncStub()
210 unsigned getMaxIFuncStubSize() const;
211
212 void processNewSymbol(const SymbolRef &ObjSymbol,
213 SymbolTableEntry &Entry) override;
214 bool relocationNeedsGot(const RelocationRef &R) const override;
215 bool relocationNeedsStub(const RelocationRef &R) const override;
216
217 // Process a GOTTPOFF TLS relocation for x86-64
218 // NOLINTNEXTLINE(readability-identifier-naming)
219 void processX86_64GOTTPOFFRelocation(unsigned SectionID, uint64_t Offset,
220 RelocationValueRef Value,
221 int64_t Addend);
222 // Process a TLSLD/TLSGD relocation for x86-64
223 // NOLINTNEXTLINE(readability-identifier-naming)
224 void processX86_64TLSRelocation(unsigned SectionID, uint64_t Offset,
225 uint64_t RelType, RelocationValueRef Value,
226 int64_t Addend,
227 const RelocationRef &GetAddrRelocation);
228
229public:
230 RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr,
231 JITSymbolResolver &Resolver);
232 ~RuntimeDyldELF() override;
233
234 static std::unique_ptr<RuntimeDyldELF>
235 create(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MemMgr,
236 JITSymbolResolver &Resolver);
237
238 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
239 loadObject(const object::ObjectFile &O) override;
240
241 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override;
242 Expected<relocation_iterator>
243 processRelocationRef(unsigned SectionID, relocation_iterator RelI,
244 const ObjectFile &Obj,
245 ObjSectionToIDMap &ObjSectionToID,
246 StubMap &Stubs) override;
247 bool isCompatibleFile(const object::ObjectFile &Obj) const override;
248 void registerEHFrames() override;
249 Error finalizeLoad(const ObjectFile &Obj,
250 ObjSectionToIDMap &SectionMap) override;
251};
252
253} // end namespace llvm
254
255#endif // LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDELF_H
256