1//===-- RuntimeDyldMachOX86_64.h ---- MachO/X86_64 specific code. -*- 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#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOX86_64_H
10#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOX86_64_H
11
12#include "../RuntimeDyldMachO.h"
13
14#define DEBUG_TYPE "dyld"
15
16namespace llvm {
17
18class RuntimeDyldMachOX86_64
19 : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOX86_64> {
20public:
21
22 typedef uint64_t TargetPtrT;
23
24 RuntimeDyldMachOX86_64(RuntimeDyld::MemoryManager &MM,
25 JITSymbolResolver &Resolver)
26 : RuntimeDyldMachOCRTPBase(MM, Resolver) {}
27
28 unsigned getMaxStubSize() const override { return 8; }
29
30 Align getStubAlignment() override { return Align(8); }
31
32 Expected<relocation_iterator>
33 processRelocationRef(unsigned SectionID, relocation_iterator RelI,
34 const ObjectFile &BaseObjT,
35 ObjSectionToIDMap &ObjSectionToID,
36 StubMap &Stubs) override {
37 const MachOObjectFile &Obj =
38 static_cast<const MachOObjectFile &>(BaseObjT);
39 MachO::any_relocation_info RelInfo =
40 Obj.getRelocation(Rel: RelI->getRawDataRefImpl());
41 uint32_t RelType = Obj.getAnyRelocationType(RE: RelInfo);
42
43 if (RelType == MachO::X86_64_RELOC_SUBTRACTOR)
44 return processSubtractRelocation(SectionID, RelI, BaseObj: Obj, ObjSectionToID);
45
46 assert(!Obj.isRelocationScattered(RelInfo) &&
47 "Scattered relocations not supported on X86_64");
48
49 RelocationEntry RE(getRelocationEntry(SectionID, BaseTObj: Obj, RI: RelI));
50 RE.Addend = memcpyAddend(RE);
51 RelocationValueRef Value;
52 if (auto ValueOrErr = getRelocationValueRef(BaseTObj: Obj, RI: RelI, RE, ObjSectionToID))
53 Value = *ValueOrErr;
54 else
55 return ValueOrErr.takeError();
56
57 bool IsExtern = Obj.getPlainRelocationExternal(RE: RelInfo);
58 if (!IsExtern && RE.IsPCRel)
59 makeValueAddendPCRel(Value, RI: RelI, OffsetToNextPC: 1 << RE.Size);
60
61 switch (RelType) {
62 UNIMPLEMENTED_RELOC(MachO::X86_64_RELOC_TLV);
63 default:
64 if (RelType > MachO::X86_64_RELOC_TLV)
65 return make_error<RuntimeDyldError>(Args: ("MachO X86_64 relocation type " +
66 Twine(RelType) +
67 " is out of range").str());
68 break;
69 }
70
71 if (RE.RelType == MachO::X86_64_RELOC_GOT ||
72 RE.RelType == MachO::X86_64_RELOC_GOT_LOAD)
73 processGOTRelocation(RE, Value, Stubs);
74 else {
75 RE.Addend = Value.Offset;
76 if (Value.SymbolName)
77 addRelocationForSymbol(RE, SymbolName: Value.SymbolName);
78 else
79 addRelocationForSection(RE, SectionID: Value.SectionID);
80 }
81
82 return ++RelI;
83 }
84
85 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {
86 LLVM_DEBUG(dumpRelocationToResolve(RE, Value));
87 const SectionEntry &Section = Sections[RE.SectionID];
88 uint8_t *LocalAddress = Section.getAddressWithOffset(OffsetBytes: RE.Offset);
89
90 // If the relocation is PC-relative, the value to be encoded is the
91 // pointer difference.
92 if (RE.IsPCRel) {
93 // FIXME: It seems this value needs to be adjusted by 4 for an effective
94 // PC address. Is that expected? Only for branches, perhaps?
95 uint64_t FinalAddress = Section.getLoadAddressWithOffset(OffsetBytes: RE.Offset);
96 Value -= FinalAddress + 4;
97 }
98
99 switch (RE.RelType) {
100 default:
101 llvm_unreachable("Invalid relocation type!");
102 case MachO::X86_64_RELOC_SIGNED_1:
103 case MachO::X86_64_RELOC_SIGNED_2:
104 case MachO::X86_64_RELOC_SIGNED_4:
105 case MachO::X86_64_RELOC_SIGNED:
106 case MachO::X86_64_RELOC_UNSIGNED:
107 case MachO::X86_64_RELOC_BRANCH:
108 writeBytesUnaligned(Value: Value + RE.Addend, Dst: LocalAddress, Size: 1 << RE.Size);
109 break;
110 case MachO::X86_64_RELOC_SUBTRACTOR: {
111 uint64_t SectionABase = Sections[RE.Sections.SectionA].getLoadAddress();
112 uint64_t SectionBBase = Sections[RE.Sections.SectionB].getLoadAddress();
113 assert((Value == SectionABase || Value == SectionBBase) &&
114 "Unexpected SUBTRACTOR relocation value.");
115 Value = SectionABase - SectionBBase + RE.Addend;
116 writeBytesUnaligned(Value, Dst: LocalAddress, Size: 1 << RE.Size);
117 break;
118 }
119 }
120 }
121
122 Error finalizeSection(const ObjectFile &Obj, unsigned SectionID,
123 const SectionRef &Section) {
124 return Error::success();
125 }
126
127private:
128 void processGOTRelocation(const RelocationEntry &RE,
129 RelocationValueRef &Value, StubMap &Stubs) {
130 SectionEntry &Section = Sections[RE.SectionID];
131 assert(RE.IsPCRel);
132 assert(RE.Size == 2);
133 Value.Offset -= RE.Addend;
134 RuntimeDyldMachO::StubMap::const_iterator i = Stubs.find(x: Value);
135 uint8_t *Addr;
136 if (i != Stubs.end()) {
137 Addr = Section.getAddressWithOffset(OffsetBytes: i->second);
138 } else {
139 Stubs[Value] = Section.getStubOffset();
140 uint8_t *GOTEntry = Section.getAddressWithOffset(OffsetBytes: Section.getStubOffset());
141 RelocationEntry GOTRE(RE.SectionID, Section.getStubOffset(),
142 MachO::X86_64_RELOC_UNSIGNED, Value.Offset, false,
143 3);
144 if (Value.SymbolName)
145 addRelocationForSymbol(RE: GOTRE, SymbolName: Value.SymbolName);
146 else
147 addRelocationForSection(RE: GOTRE, SectionID: Value.SectionID);
148 Section.advanceStubOffset(StubSize: 8);
149 Addr = GOTEntry;
150 }
151 RelocationEntry TargetRE(RE.SectionID, RE.Offset,
152 MachO::X86_64_RELOC_UNSIGNED, RE.Addend, true, 2);
153 resolveRelocation(RE: TargetRE, Value: (uint64_t)Addr);
154 }
155
156 Expected<relocation_iterator>
157 processSubtractRelocation(unsigned SectionID, relocation_iterator RelI,
158 const MachOObjectFile &BaseObj,
159 ObjSectionToIDMap &ObjSectionToID) {
160 const MachOObjectFile &Obj =
161 static_cast<const MachOObjectFile&>(BaseObj);
162 MachO::any_relocation_info RE =
163 Obj.getRelocation(Rel: RelI->getRawDataRefImpl());
164
165 unsigned Size = Obj.getAnyRelocationLength(RE);
166 uint64_t Offset = RelI->getOffset();
167 uint8_t *LocalAddress = Sections[SectionID].getAddressWithOffset(OffsetBytes: Offset);
168 unsigned NumBytes = 1 << Size;
169 int64_t Addend =
170 SignExtend64(X: readBytesUnaligned(Src: LocalAddress, Size: NumBytes), B: NumBytes * 8);
171
172 unsigned SectionBID = ~0U;
173 uint64_t SectionBOffset = 0;
174
175 MachO::any_relocation_info RelInfo =
176 Obj.getRelocation(Rel: RelI->getRawDataRefImpl());
177
178 bool AIsExternal = BaseObj.getPlainRelocationExternal(RE: RelInfo);
179
180 if (AIsExternal) {
181 Expected<StringRef> SubtrahendNameOrErr = RelI->getSymbol()->getName();
182 if (!SubtrahendNameOrErr)
183 return SubtrahendNameOrErr.takeError();
184 auto SubtrahendI = GlobalSymbolTable.find(Key: *SubtrahendNameOrErr);
185 SectionBID = SubtrahendI->second.getSectionID();
186 SectionBOffset = SubtrahendI->second.getOffset();
187 } else {
188 SectionRef SecB = Obj.getAnyRelocationSection(RE: RelInfo);
189 bool IsCode = SecB.isText();
190 Expected<unsigned> SectionBIDOrErr =
191 findOrEmitSection(Obj, Section: SecB, IsCode, LocalSections&: ObjSectionToID);
192 if (!SectionBIDOrErr)
193 return SectionBIDOrErr.takeError();
194 SectionBID = *SectionBIDOrErr;
195 Addend += SecB.getAddress();
196 }
197
198 ++RelI;
199
200 unsigned SectionAID = ~0U;
201 uint64_t SectionAOffset = 0;
202
203 RelInfo = Obj.getRelocation(Rel: RelI->getRawDataRefImpl());
204
205 bool BIsExternal = BaseObj.getPlainRelocationExternal(RE: RelInfo);
206 if (BIsExternal) {
207 Expected<StringRef> MinuendNameOrErr = RelI->getSymbol()->getName();
208 if (!MinuendNameOrErr)
209 return MinuendNameOrErr.takeError();
210 auto MinuendI = GlobalSymbolTable.find(Key: *MinuendNameOrErr);
211 SectionAID = MinuendI->second.getSectionID();
212 SectionAOffset = MinuendI->second.getOffset();
213 } else {
214 SectionRef SecA = Obj.getAnyRelocationSection(RE: RelInfo);
215 bool IsCode = SecA.isText();
216 Expected<unsigned> SectionAIDOrErr =
217 findOrEmitSection(Obj, Section: SecA, IsCode, LocalSections&: ObjSectionToID);
218 if (!SectionAIDOrErr)
219 return SectionAIDOrErr.takeError();
220 SectionAID = *SectionAIDOrErr;
221 Addend -= SecA.getAddress();
222 }
223
224 RelocationEntry R(SectionID, Offset, MachO::X86_64_RELOC_SUBTRACTOR, (uint64_t)Addend,
225 SectionAID, SectionAOffset, SectionBID, SectionBOffset,
226 false, Size);
227
228 addRelocationForSection(RE: R, SectionID: SectionAID);
229
230 return ++RelI;
231 }
232
233};
234}
235
236#undef DEBUG_TYPE
237
238#endif
239