1//===-- RuntimeDyldMachO.cpp - 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// Implementation of the MC-JIT runtime dynamic linker.
10//
11//===----------------------------------------------------------------------===//
12
13#include "RuntimeDyldMachO.h"
14#include "Targets/RuntimeDyldMachOAArch64.h"
15#include "Targets/RuntimeDyldMachOARM.h"
16#include "Targets/RuntimeDyldMachOI386.h"
17#include "Targets/RuntimeDyldMachOX86_64.h"
18#include "llvm/ADT/STLExtras.h"
19#include "llvm/ADT/StringRef.h"
20
21using namespace llvm;
22using namespace llvm::object;
23
24#define DEBUG_TYPE "dyld"
25
26namespace {
27
28class LoadedMachOObjectInfo final
29 : public LoadedObjectInfoHelper<LoadedMachOObjectInfo,
30 RuntimeDyld::LoadedObjectInfo> {
31public:
32 LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
33 ObjSectionToIDMap ObjSecToIDMap)
34 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
35
36 OwningBinary<ObjectFile>
37 getObjectForDebug(const ObjectFile &Obj) const override {
38 return OwningBinary<ObjectFile>();
39 }
40};
41
42}
43
44namespace llvm {
45
46int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
47 unsigned NumBytes = 1 << RE.Size;
48 uint8_t *Src = Sections[RE.SectionID].getAddress() + RE.Offset;
49
50 return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
51}
52
53Expected<relocation_iterator>
54RuntimeDyldMachO::processScatteredVANILLA(
55 unsigned SectionID, relocation_iterator RelI,
56 const ObjectFile &BaseObjT,
57 RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID,
58 bool TargetIsLocalThumbFunc) {
59 const MachOObjectFile &Obj =
60 static_cast<const MachOObjectFile&>(BaseObjT);
61 MachO::any_relocation_info RE =
62 Obj.getRelocation(RelI->getRawDataRefImpl());
63
64 SectionEntry &Section = Sections[SectionID];
65 uint32_t RelocType = Obj.getAnyRelocationType(RE);
66 bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
67 unsigned Size = Obj.getAnyRelocationLength(RE);
68 uint64_t Offset = RelI->getOffset();
69 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
70 unsigned NumBytes = 1 << Size;
71 int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
72
73 unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
74 section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
75 assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
76 uint64_t SectionBaseAddr = TargetSI->getAddress();
77 SectionRef TargetSection = *TargetSI;
78 bool IsCode = TargetSection.isText();
79 uint32_t TargetSectionID = ~0U;
80 if (auto TargetSectionIDOrErr =
81 findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID))
82 TargetSectionID = *TargetSectionIDOrErr;
83 else
84 return TargetSectionIDOrErr.takeError();
85
86 Addend -= SectionBaseAddr;
87 RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
88 R.IsTargetThumbFunc = TargetIsLocalThumbFunc;
89
90 addRelocationForSection(R, TargetSectionID);
91
92 return ++RelI;
93}
94
95
96Expected<RelocationValueRef>
97RuntimeDyldMachO::getRelocationValueRef(
98 const ObjectFile &BaseTObj, const relocation_iterator &RI,
99 const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
100
101 const MachOObjectFile &Obj =
102 static_cast<const MachOObjectFile &>(BaseTObj);
103 MachO::any_relocation_info RelInfo =
104 Obj.getRelocation(RI->getRawDataRefImpl());
105 RelocationValueRef Value;
106
107 bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
108 if (IsExternal) {
109 symbol_iterator Symbol = RI->getSymbol();
110 StringRef TargetName;
111 if (auto TargetNameOrErr = Symbol->getName())
112 TargetName = *TargetNameOrErr;
113 else
114 return TargetNameOrErr.takeError();
115 RTDyldSymbolTable::const_iterator SI =
116 GlobalSymbolTable.find(TargetName.data());
117 if (SI != GlobalSymbolTable.end()) {
118 const auto &SymInfo = SI->second;
119 Value.SectionID = SymInfo.getSectionID();
120 Value.Offset = SymInfo.getOffset() + RE.Addend;
121 } else {
122 Value.SymbolName = TargetName.data();
123 Value.Offset = RE.Addend;
124 }
125 } else {
126 SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
127 bool IsCode = Sec.isText();
128 if (auto SectionIDOrErr = findOrEmitSection(Obj, Sec, IsCode,
129 ObjSectionToID))
130 Value.SectionID = *SectionIDOrErr;
131 else
132 return SectionIDOrErr.takeError();
133 uint64_t Addr = Sec.getAddress();
134 Value.Offset = RE.Addend - Addr;
135 }
136
137 return Value;
138}
139
140void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
141 const relocation_iterator &RI,
142 unsigned OffsetToNextPC) {
143 auto &O = *cast<MachOObjectFile>(RI->getObject());
144 section_iterator SecI = O.getRelocationRelocatedSection(RI);
145 Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
146}
147
148void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
149 uint64_t Value) const {
150 const SectionEntry &Section = Sections[RE.SectionID];
151 uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
152 uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
153
154 dbgs() << "resolveRelocation Section: " << RE.SectionID
155 << " LocalAddress: " << format("%p", LocalAddress)
156 << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
157 << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
158 << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
159 << " Size: " << (1 << RE.Size) << "\n";
160}
161
162section_iterator
163RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
164 uint64_t Addr) {
165 section_iterator SI = Obj.section_begin();
166 section_iterator SE = Obj.section_end();
167
168 for (; SI != SE; ++SI) {
169 uint64_t SAddr = SI->getAddress();
170 uint64_t SSize = SI->getSize();
171 if ((Addr >= SAddr) && (Addr < SAddr + SSize))
172 return SI;
173 }
174
175 return SE;
176}
177
178
179// Populate __pointers section.
180Error RuntimeDyldMachO::populateIndirectSymbolPointersSection(
181 const MachOObjectFile &Obj,
182 const SectionRef &PTSection,
183 unsigned PTSectionID) {
184 assert(!Obj.is64Bit() &&
185 "Pointer table section not supported in 64-bit MachO.");
186
187 MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
188 MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
189 uint32_t PTSectionSize = Sec32.size;
190 unsigned FirstIndirectSymbol = Sec32.reserved1;
191 const unsigned PTEntrySize = 4;
192 unsigned NumPTEntries = PTSectionSize / PTEntrySize;
193 unsigned PTEntryOffset = 0;
194
195 assert((PTSectionSize % PTEntrySize) == 0 &&
196 "Pointers section does not contain a whole number of stubs?");
197
198 LLVM_DEBUG(dbgs() << "Populating pointer table section "
199 << Sections[PTSectionID].getName() << ", Section ID "
200 << PTSectionID << ", " << NumPTEntries << " entries, "
201 << PTEntrySize << " bytes each:\n");
202
203 for (unsigned i = 0; i < NumPTEntries; ++i) {
204 unsigned SymbolIndex =
205 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
206 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
207 StringRef IndirectSymbolName;
208 if (auto IndirectSymbolNameOrErr = SI->getName())
209 IndirectSymbolName = *IndirectSymbolNameOrErr;
210 else
211 return IndirectSymbolNameOrErr.takeError();
212 LLVM_DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
213 << ", PT offset: " << PTEntryOffset << "\n");
214 RelocationEntry RE(PTSectionID, PTEntryOffset,
215 MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
216 addRelocationForSymbol(RE, IndirectSymbolName);
217 PTEntryOffset += PTEntrySize;
218 }
219 return Error::success();
220}
221
222bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
223 return Obj.isMachO();
224}
225
226template <typename Impl>
227Error
228RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
229 ObjSectionToIDMap &SectionMap) {
230 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
231 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
232 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
233
234 for (const auto &Section : Obj.sections()) {
235 StringRef Name;
236 if (Expected<StringRef> NameOrErr = Section.getName())
237 Name = *NameOrErr;
238 else
239 consumeError(NameOrErr.takeError());
240
241 // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
242 // if they're present. Otherwise call down to the impl to handle other
243 // sections that have already been emitted.
244 if (Name == "__text") {
245 if (auto TextSIDOrErr = findOrEmitSection(Obj, Section, true, SectionMap))
246 TextSID = *TextSIDOrErr;
247 else
248 return TextSIDOrErr.takeError();
249 } else if (Name == "__eh_frame") {
250 if (auto EHFrameSIDOrErr = findOrEmitSection(Obj, Section, false,
251 SectionMap))
252 EHFrameSID = *EHFrameSIDOrErr;
253 else
254 return EHFrameSIDOrErr.takeError();
255 } else if (Name == "__gcc_except_tab") {
256 if (auto ExceptTabSIDOrErr = findOrEmitSection(Obj, Section, true,
257 SectionMap))
258 ExceptTabSID = *ExceptTabSIDOrErr;
259 else
260 return ExceptTabSIDOrErr.takeError();
261 } else {
262 auto I = SectionMap.find(Section);
263 if (I != SectionMap.end())
264 if (auto Err = impl().finalizeSection(Obj, I->second, Section))
265 return Err;
266 }
267 }
268 UnregisteredEHFrameSections.push_back(
269 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
270
271 return Error::success();
272}
273
274template <typename Impl>
275unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
276 int64_t DeltaForText,
277 int64_t DeltaForEH) {
278 typedef typename Impl::TargetPtrT TargetPtrT;
279
280 LLVM_DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
281 << ", Delta for EH: " << DeltaForEH << "\n");
282 uint32_t Length = readBytesUnaligned(P, 4);
283 P += 4;
284 uint8_t *Ret = P + Length;
285 uint32_t Offset = readBytesUnaligned(P, 4);
286 if (Offset == 0) // is a CIE
287 return Ret;
288
289 P += 4;
290 TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
291 TargetPtrT NewLocation = FDELocation - DeltaForText;
292 writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
293
294 P += sizeof(TargetPtrT);
295
296 // Skip the FDE address range
297 P += sizeof(TargetPtrT);
298
299 uint8_t Augmentationsize = *P;
300 P += 1;
301 if (Augmentationsize != 0) {
302 TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
303 TargetPtrT NewLSDA = LSDA - DeltaForEH;
304 writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
305 }
306
307 return Ret;
308}
309
310static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
311 int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
312 static_cast<int64_t>(B->getObjAddress());
313 int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
314 return ObjDistance - MemDistance;
315}
316
317template <typename Impl>
318void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
319
320 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
321 EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
322 if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
323 SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
324 continue;
325 SectionEntry *Text = &Sections[SectionInfo.TextSID];
326 SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
327 SectionEntry *ExceptTab = nullptr;
328 if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
329 ExceptTab = &Sections[SectionInfo.ExceptTabSID];
330
331 int64_t DeltaForText = computeDelta(Text, EHFrame);
332 int64_t DeltaForEH = 0;
333 if (ExceptTab)
334 DeltaForEH = computeDelta(ExceptTab, EHFrame);
335
336 uint8_t *P = EHFrame->getAddress();
337 uint8_t *End = P + EHFrame->getSize();
338 while (P != End) {
339 P = processFDE(P, DeltaForText, DeltaForEH);
340 }
341
342 MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
343 EHFrame->getSize());
344 }
345 UnregisteredEHFrameSections.clear();
346}
347
348std::unique_ptr<RuntimeDyldMachO>
349RuntimeDyldMachO::create(Triple::ArchType Arch,
350 RuntimeDyld::MemoryManager &MemMgr,
351 JITSymbolResolver &Resolver) {
352 switch (Arch) {
353 default:
354 llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
355 break;
356 case Triple::arm:
357 return std::make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
358 case Triple::aarch64:
359 return std::make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
360 case Triple::aarch64_32:
361 return std::make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
362 case Triple::x86:
363 return std::make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
364 case Triple::x86_64:
365 return std::make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
366 }
367}
368
369std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
370RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
371 if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
372 return std::make_unique<LoadedMachOObjectInfo>(*this,
373 *ObjSectionToIDOrErr);
374 else {
375 HasError = true;
376 raw_string_ostream ErrStream(ErrorStr);
377 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream);
378 return nullptr;
379 }
380}
381
382} // end namespace llvm
383