1 //===-- RuntimeDyldMachO.cpp - 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 // Implementation of the MC-JIT runtime dynamic linker.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "RuntimeDyldMachO.h"
15 #include "Targets/RuntimeDyldMachOAArch64.h"
16 #include "Targets/RuntimeDyldMachOARM.h"
17 #include "Targets/RuntimeDyldMachOI386.h"
18 #include "Targets/RuntimeDyldMachOX86_64.h"
19 #include "llvm/ADT/STLExtras.h"
20 #include "llvm/ADT/StringRef.h"
21
22 using namespace llvm;
23 using namespace llvm::object;
24
25 #define DEBUG_TYPE "dyld"
26
27 namespace {
28
29 class LoadedMachOObjectInfo final
30 : public RuntimeDyld::LoadedObjectInfoHelper<LoadedMachOObjectInfo> {
31 public:
LoadedMachOObjectInfo(RuntimeDyldImpl & RTDyld,ObjSectionToIDMap ObjSecToIDMap)32 LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
33 ObjSectionToIDMap ObjSecToIDMap)
34 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
35
36 OwningBinary<ObjectFile>
getObjectForDebug(const ObjectFile & Obj) const37 getObjectForDebug(const ObjectFile &Obj) const override {
38 return OwningBinary<ObjectFile>();
39 }
40 };
41
42 }
43
44 namespace llvm {
45
memcpyAddend(const RelocationEntry & RE) const46 int64_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
53 Expected<relocation_iterator>
processScatteredVANILLA(unsigned SectionID,relocation_iterator RelI,const ObjectFile & BaseObjT,RuntimeDyldMachO::ObjSectionToIDMap & ObjSectionToID)54 RuntimeDyldMachO::processScatteredVANILLA(
55 unsigned SectionID, relocation_iterator RelI,
56 const ObjectFile &BaseObjT,
57 RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID) {
58 const MachOObjectFile &Obj =
59 static_cast<const MachOObjectFile&>(BaseObjT);
60 MachO::any_relocation_info RE =
61 Obj.getRelocation(RelI->getRawDataRefImpl());
62
63 SectionEntry &Section = Sections[SectionID];
64 uint32_t RelocType = Obj.getAnyRelocationType(RE);
65 bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
66 unsigned Size = Obj.getAnyRelocationLength(RE);
67 uint64_t Offset = RelI->getOffset();
68 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
69 unsigned NumBytes = 1 << Size;
70 int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
71
72 unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
73 section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
74 assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
75 uint64_t SectionBaseAddr = TargetSI->getAddress();
76 SectionRef TargetSection = *TargetSI;
77 bool IsCode = TargetSection.isText();
78 uint32_t TargetSectionID = ~0U;
79 if (auto TargetSectionIDOrErr =
80 findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID))
81 TargetSectionID = *TargetSectionIDOrErr;
82 else
83 return TargetSectionIDOrErr.takeError();
84
85 Addend -= SectionBaseAddr;
86 RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
87
88 addRelocationForSection(R, TargetSectionID);
89
90 return ++RelI;
91 }
92
93
94 Expected<RelocationValueRef>
getRelocationValueRef(const ObjectFile & BaseTObj,const relocation_iterator & RI,const RelocationEntry & RE,ObjSectionToIDMap & ObjSectionToID)95 RuntimeDyldMachO::getRelocationValueRef(
96 const ObjectFile &BaseTObj, const relocation_iterator &RI,
97 const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
98
99 const MachOObjectFile &Obj =
100 static_cast<const MachOObjectFile &>(BaseTObj);
101 MachO::any_relocation_info RelInfo =
102 Obj.getRelocation(RI->getRawDataRefImpl());
103 RelocationValueRef Value;
104
105 bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
106 if (IsExternal) {
107 symbol_iterator Symbol = RI->getSymbol();
108 StringRef TargetName;
109 if (auto TargetNameOrErr = Symbol->getName())
110 TargetName = *TargetNameOrErr;
111 else
112 return TargetNameOrErr.takeError();
113 RTDyldSymbolTable::const_iterator SI =
114 GlobalSymbolTable.find(TargetName.data());
115 if (SI != GlobalSymbolTable.end()) {
116 const auto &SymInfo = SI->second;
117 Value.SectionID = SymInfo.getSectionID();
118 Value.Offset = SymInfo.getOffset() + RE.Addend;
119 } else {
120 Value.SymbolName = TargetName.data();
121 Value.Offset = RE.Addend;
122 }
123 } else {
124 SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
125 bool IsCode = Sec.isText();
126 if (auto SectionIDOrErr = findOrEmitSection(Obj, Sec, IsCode,
127 ObjSectionToID))
128 Value.SectionID = *SectionIDOrErr;
129 else
130 return SectionIDOrErr.takeError();
131 uint64_t Addr = Sec.getAddress();
132 Value.Offset = RE.Addend - Addr;
133 }
134
135 return Value;
136 }
137
makeValueAddendPCRel(RelocationValueRef & Value,const relocation_iterator & RI,unsigned OffsetToNextPC)138 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
139 const relocation_iterator &RI,
140 unsigned OffsetToNextPC) {
141 auto &O = *cast<MachOObjectFile>(RI->getObject());
142 section_iterator SecI = O.getRelocationRelocatedSection(RI);
143 Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
144 }
145
dumpRelocationToResolve(const RelocationEntry & RE,uint64_t Value) const146 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
147 uint64_t Value) const {
148 const SectionEntry &Section = Sections[RE.SectionID];
149 uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
150 uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
151
152 dbgs() << "resolveRelocation Section: " << RE.SectionID
153 << " LocalAddress: " << format("%p", LocalAddress)
154 << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
155 << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
156 << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
157 << " Size: " << (1 << RE.Size) << "\n";
158 }
159
160 section_iterator
getSectionByAddress(const MachOObjectFile & Obj,uint64_t Addr)161 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
162 uint64_t Addr) {
163 section_iterator SI = Obj.section_begin();
164 section_iterator SE = Obj.section_end();
165
166 for (; SI != SE; ++SI) {
167 uint64_t SAddr = SI->getAddress();
168 uint64_t SSize = SI->getSize();
169 if ((Addr >= SAddr) && (Addr < SAddr + SSize))
170 return SI;
171 }
172
173 return SE;
174 }
175
176
177 // Populate __pointers section.
populateIndirectSymbolPointersSection(const MachOObjectFile & Obj,const SectionRef & PTSection,unsigned PTSectionID)178 Error RuntimeDyldMachO::populateIndirectSymbolPointersSection(
179 const MachOObjectFile &Obj,
180 const SectionRef &PTSection,
181 unsigned PTSectionID) {
182 assert(!Obj.is64Bit() &&
183 "Pointer table section not supported in 64-bit MachO.");
184
185 MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
186 MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
187 uint32_t PTSectionSize = Sec32.size;
188 unsigned FirstIndirectSymbol = Sec32.reserved1;
189 const unsigned PTEntrySize = 4;
190 unsigned NumPTEntries = PTSectionSize / PTEntrySize;
191 unsigned PTEntryOffset = 0;
192
193 assert((PTSectionSize % PTEntrySize) == 0 &&
194 "Pointers section does not contain a whole number of stubs?");
195
196 DEBUG(dbgs() << "Populating pointer table section "
197 << Sections[PTSectionID].getName() << ", Section ID "
198 << PTSectionID << ", " << NumPTEntries << " entries, "
199 << PTEntrySize << " bytes each:\n");
200
201 for (unsigned i = 0; i < NumPTEntries; ++i) {
202 unsigned SymbolIndex =
203 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
204 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
205 StringRef IndirectSymbolName;
206 if (auto IndirectSymbolNameOrErr = SI->getName())
207 IndirectSymbolName = *IndirectSymbolNameOrErr;
208 else
209 return IndirectSymbolNameOrErr.takeError();
210 DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
211 << ", PT offset: " << PTEntryOffset << "\n");
212 RelocationEntry RE(PTSectionID, PTEntryOffset,
213 MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
214 addRelocationForSymbol(RE, IndirectSymbolName);
215 PTEntryOffset += PTEntrySize;
216 }
217 return Error::success();
218 }
219
isCompatibleFile(const object::ObjectFile & Obj) const220 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
221 return Obj.isMachO();
222 }
223
224 template <typename Impl>
225 Error
finalizeLoad(const ObjectFile & Obj,ObjSectionToIDMap & SectionMap)226 RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
227 ObjSectionToIDMap &SectionMap) {
228 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
229 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
230 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
231
232 for (const auto &Section : Obj.sections()) {
233 StringRef Name;
234 Section.getName(Name);
235
236 // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
237 // if they're present. Otherwise call down to the impl to handle other
238 // sections that have already been emitted.
239 if (Name == "__text") {
240 if (auto TextSIDOrErr = findOrEmitSection(Obj, Section, true, SectionMap))
241 TextSID = *TextSIDOrErr;
242 else
243 return TextSIDOrErr.takeError();
244 } else if (Name == "__eh_frame") {
245 if (auto EHFrameSIDOrErr = findOrEmitSection(Obj, Section, false,
246 SectionMap))
247 EHFrameSID = *EHFrameSIDOrErr;
248 else
249 return EHFrameSIDOrErr.takeError();
250 } else if (Name == "__gcc_except_tab") {
251 if (auto ExceptTabSIDOrErr = findOrEmitSection(Obj, Section, true,
252 SectionMap))
253 ExceptTabSID = *ExceptTabSIDOrErr;
254 else
255 return ExceptTabSIDOrErr.takeError();
256 } else {
257 auto I = SectionMap.find(Section);
258 if (I != SectionMap.end())
259 if (auto Err = impl().finalizeSection(Obj, I->second, Section))
260 return Err;
261 }
262 }
263 UnregisteredEHFrameSections.push_back(
264 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
265
266 return Error::success();
267 }
268
269 template <typename Impl>
processFDE(uint8_t * P,int64_t DeltaForText,int64_t DeltaForEH)270 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
271 int64_t DeltaForText,
272 int64_t DeltaForEH) {
273 typedef typename Impl::TargetPtrT TargetPtrT;
274
275 DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
276 << ", Delta for EH: " << DeltaForEH << "\n");
277 uint32_t Length = readBytesUnaligned(P, 4);
278 P += 4;
279 uint8_t *Ret = P + Length;
280 uint32_t Offset = readBytesUnaligned(P, 4);
281 if (Offset == 0) // is a CIE
282 return Ret;
283
284 P += 4;
285 TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
286 TargetPtrT NewLocation = FDELocation - DeltaForText;
287 writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
288
289 P += sizeof(TargetPtrT);
290
291 // Skip the FDE address range
292 P += sizeof(TargetPtrT);
293
294 uint8_t Augmentationsize = *P;
295 P += 1;
296 if (Augmentationsize != 0) {
297 TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
298 TargetPtrT NewLSDA = LSDA - DeltaForEH;
299 writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
300 }
301
302 return Ret;
303 }
304
computeDelta(SectionEntry * A,SectionEntry * B)305 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
306 int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
307 static_cast<int64_t>(B->getObjAddress());
308 int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
309 return ObjDistance - MemDistance;
310 }
311
312 template <typename Impl>
registerEHFrames()313 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
314
315 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
316 EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
317 if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
318 SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
319 continue;
320 SectionEntry *Text = &Sections[SectionInfo.TextSID];
321 SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
322 SectionEntry *ExceptTab = nullptr;
323 if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
324 ExceptTab = &Sections[SectionInfo.ExceptTabSID];
325
326 int64_t DeltaForText = computeDelta(Text, EHFrame);
327 int64_t DeltaForEH = 0;
328 if (ExceptTab)
329 DeltaForEH = computeDelta(ExceptTab, EHFrame);
330
331 uint8_t *P = EHFrame->getAddress();
332 uint8_t *End = P + EHFrame->getSize();
333 while (P != End) {
334 P = processFDE(P, DeltaForText, DeltaForEH);
335 }
336
337 MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
338 EHFrame->getSize());
339 }
340 UnregisteredEHFrameSections.clear();
341 }
342
343 std::unique_ptr<RuntimeDyldMachO>
create(Triple::ArchType Arch,RuntimeDyld::MemoryManager & MemMgr,RuntimeDyld::SymbolResolver & Resolver)344 RuntimeDyldMachO::create(Triple::ArchType Arch,
345 RuntimeDyld::MemoryManager &MemMgr,
346 RuntimeDyld::SymbolResolver &Resolver) {
347 switch (Arch) {
348 default:
349 llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
350 break;
351 case Triple::arm:
352 return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
353 case Triple::aarch64:
354 return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
355 case Triple::x86:
356 return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
357 case Triple::x86_64:
358 return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
359 }
360 }
361
362 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
loadObject(const object::ObjectFile & O)363 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
364 if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
365 return llvm::make_unique<LoadedMachOObjectInfo>(*this,
366 *ObjSectionToIDOrErr);
367 else {
368 HasError = true;
369 raw_string_ostream ErrStream(ErrorStr);
370 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, "");
371 return nullptr;
372 }
373 }
374
375 } // end namespace llvm
376