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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 0 : class LoadedMachOObjectInfo final
30 : : public LoadedObjectInfoHelper<LoadedMachOObjectInfo,
31 : RuntimeDyld::LoadedObjectInfo> {
32 : public:
33 : LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
34 : ObjSectionToIDMap ObjSecToIDMap)
35 11 : : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
36 :
37 : OwningBinary<ObjectFile>
38 0 : getObjectForDebug(const ObjectFile &Obj) const override {
39 0 : return OwningBinary<ObjectFile>();
40 : }
41 : };
42 :
43 : }
44 :
45 : namespace llvm {
46 :
47 32 : int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
48 32 : unsigned NumBytes = 1 << RE.Size;
49 32 : uint8_t *Src = Sections[RE.SectionID].getAddress() + RE.Offset;
50 :
51 32 : return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
52 : }
53 :
54 : Expected<relocation_iterator>
55 2 : RuntimeDyldMachO::processScatteredVANILLA(
56 : unsigned SectionID, relocation_iterator RelI,
57 : const ObjectFile &BaseObjT,
58 : RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID,
59 : bool TargetIsLocalThumbFunc) {
60 : const MachOObjectFile &Obj =
61 : static_cast<const MachOObjectFile&>(BaseObjT);
62 : MachO::any_relocation_info RE =
63 2 : Obj.getRelocation(RelI->getRawDataRefImpl());
64 :
65 2 : SectionEntry &Section = Sections[SectionID];
66 2 : uint32_t RelocType = Obj.getAnyRelocationType(RE);
67 2 : bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
68 2 : unsigned Size = Obj.getAnyRelocationLength(RE);
69 2 : uint64_t Offset = RelI->getOffset();
70 2 : uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
71 2 : unsigned NumBytes = 1 << Size;
72 2 : int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
73 :
74 2 : unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
75 2 : section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
76 : assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
77 2 : uint64_t SectionBaseAddr = TargetSI->getAddress();
78 2 : SectionRef TargetSection = *TargetSI;
79 2 : bool IsCode = TargetSection.isText();
80 : uint32_t TargetSectionID = ~0U;
81 2 : if (auto TargetSectionIDOrErr =
82 2 : findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID))
83 2 : TargetSectionID = *TargetSectionIDOrErr;
84 : else
85 : return TargetSectionIDOrErr.takeError();
86 :
87 2 : Addend -= SectionBaseAddr;
88 : RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
89 2 : R.IsTargetThumbFunc = TargetIsLocalThumbFunc;
90 :
91 2 : addRelocationForSection(R, TargetSectionID);
92 :
93 : return ++RelI;
94 : }
95 :
96 :
97 : Expected<RelocationValueRef>
98 47 : RuntimeDyldMachO::getRelocationValueRef(
99 : const ObjectFile &BaseTObj, const relocation_iterator &RI,
100 : const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
101 :
102 : const MachOObjectFile &Obj =
103 : static_cast<const MachOObjectFile &>(BaseTObj);
104 : MachO::any_relocation_info RelInfo =
105 47 : Obj.getRelocation(RI->getRawDataRefImpl());
106 : RelocationValueRef Value;
107 :
108 47 : bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
109 47 : if (IsExternal) {
110 21 : symbol_iterator Symbol = RI->getSymbol();
111 : StringRef TargetName;
112 21 : if (auto TargetNameOrErr = Symbol->getName())
113 21 : TargetName = *TargetNameOrErr;
114 : else
115 : return TargetNameOrErr.takeError();
116 : RTDyldSymbolTable::const_iterator SI =
117 42 : GlobalSymbolTable.find(TargetName.data());
118 42 : if (SI != GlobalSymbolTable.end()) {
119 : const auto &SymInfo = SI->second;
120 14 : Value.SectionID = SymInfo.getSectionID();
121 14 : Value.Offset = SymInfo.getOffset() + RE.Addend;
122 : } else {
123 : Value.SymbolName = TargetName.data();
124 7 : Value.Offset = RE.Addend;
125 : }
126 : } else {
127 26 : SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
128 26 : bool IsCode = Sec.isText();
129 26 : if (auto SectionIDOrErr = findOrEmitSection(Obj, Sec, IsCode,
130 26 : ObjSectionToID))
131 26 : Value.SectionID = *SectionIDOrErr;
132 : else
133 : return SectionIDOrErr.takeError();
134 26 : uint64_t Addr = Sec.getAddress();
135 26 : Value.Offset = RE.Addend - Addr;
136 : }
137 :
138 : return Value;
139 : }
140 :
141 8 : void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
142 : const relocation_iterator &RI,
143 : unsigned OffsetToNextPC) {
144 8 : auto &O = *cast<MachOObjectFile>(RI->getObject());
145 8 : section_iterator SecI = O.getRelocationRelocatedSection(RI);
146 8 : Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
147 8 : }
148 :
149 0 : void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
150 : uint64_t Value) const {
151 0 : const SectionEntry &Section = Sections[RE.SectionID];
152 0 : uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
153 0 : uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
154 :
155 0 : dbgs() << "resolveRelocation Section: " << RE.SectionID
156 0 : << " LocalAddress: " << format("%p", LocalAddress)
157 0 : << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
158 0 : << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
159 0 : << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
160 0 : << " Size: " << (1 << RE.Size) << "\n";
161 0 : }
162 :
163 : section_iterator
164 8 : RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
165 : uint64_t Addr) {
166 8 : section_iterator SI = Obj.section_begin();
167 8 : section_iterator SE = Obj.section_end();
168 :
169 20 : for (; SI != SE; ++SI) {
170 20 : uint64_t SAddr = SI->getAddress();
171 20 : uint64_t SSize = SI->getSize();
172 20 : if ((Addr >= SAddr) && (Addr < SAddr + SSize))
173 8 : return SI;
174 : }
175 :
176 0 : return SE;
177 : }
178 :
179 :
180 : // Populate __pointers section.
181 2 : Error RuntimeDyldMachO::populateIndirectSymbolPointersSection(
182 : const MachOObjectFile &Obj,
183 : const SectionRef &PTSection,
184 : unsigned PTSectionID) {
185 : assert(!Obj.is64Bit() &&
186 : "Pointer table section not supported in 64-bit MachO.");
187 :
188 2 : MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
189 2 : MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
190 2 : uint32_t PTSectionSize = Sec32.size;
191 2 : unsigned FirstIndirectSymbol = Sec32.reserved1;
192 : const unsigned PTEntrySize = 4;
193 2 : unsigned NumPTEntries = PTSectionSize / PTEntrySize;
194 : unsigned PTEntryOffset = 0;
195 :
196 : assert((PTSectionSize % PTEntrySize) == 0 &&
197 : "Pointers section does not contain a whole number of stubs?");
198 :
199 : LLVM_DEBUG(dbgs() << "Populating pointer table section "
200 : << Sections[PTSectionID].getName() << ", Section ID "
201 : << PTSectionID << ", " << NumPTEntries << " entries, "
202 : << PTEntrySize << " bytes each:\n");
203 :
204 4 : for (unsigned i = 0; i < NumPTEntries; ++i) {
205 : unsigned SymbolIndex =
206 2 : Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
207 2 : symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
208 : StringRef IndirectSymbolName;
209 2 : if (auto IndirectSymbolNameOrErr = SI->getName())
210 2 : IndirectSymbolName = *IndirectSymbolNameOrErr;
211 : else
212 : return IndirectSymbolNameOrErr.takeError();
213 : LLVM_DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
214 : << ", PT offset: " << PTEntryOffset << "\n");
215 : RelocationEntry RE(PTSectionID, PTEntryOffset,
216 2 : MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
217 2 : addRelocationForSymbol(RE, IndirectSymbolName);
218 2 : PTEntryOffset += PTEntrySize;
219 : }
220 : return Error::success();
221 : }
222 :
223 11 : bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
224 22 : return Obj.isMachO();
225 : }
226 :
227 : template <typename Impl>
228 : Error
229 11 : RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
230 : ObjSectionToIDMap &SectionMap) {
231 : unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
232 : unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
233 : unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
234 :
235 75 : for (const auto &Section : Obj.sections()) {
236 64 : StringRef Name;
237 64 : Section.getName(Name);
238 :
239 : // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
240 : // if they're present. Otherwise call down to the impl to handle other
241 : // sections that have already been emitted.
242 : if (Name == "__text") {
243 11 : if (auto TextSIDOrErr = findOrEmitSection(Obj, Section, true, SectionMap))
244 11 : TextSID = *TextSIDOrErr;
245 : else
246 : return TextSIDOrErr.takeError();
247 : } else if (Name == "__eh_frame") {
248 7 : if (auto EHFrameSIDOrErr = findOrEmitSection(Obj, Section, false,
249 : SectionMap))
250 7 : EHFrameSID = *EHFrameSIDOrErr;
251 : else
252 : return EHFrameSIDOrErr.takeError();
253 : } else if (Name == "__gcc_except_tab") {
254 0 : if (auto ExceptTabSIDOrErr = findOrEmitSection(Obj, Section, true,
255 : SectionMap))
256 0 : ExceptTabSID = *ExceptTabSIDOrErr;
257 : else
258 : return ExceptTabSIDOrErr.takeError();
259 : } else {
260 : auto I = SectionMap.find(Section);
261 6 : if (I != SectionMap.end())
262 12 : if (auto Err = impl().finalizeSection(Obj, I->second, Section))
263 : return Err;
264 : }
265 : }
266 22 : UnregisteredEHFrameSections.push_back(
267 : EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
268 :
269 : return Error::success();
270 : }
271 1 :
272 : template <typename Impl>
273 : unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
274 : int64_t DeltaForText,
275 : int64_t DeltaForEH) {
276 : typedef typename Impl::TargetPtrT TargetPtrT;
277 3 :
278 2 : LLVM_DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
279 2 : << ", Delta for EH: " << DeltaForEH << "\n");
280 : uint32_t Length = readBytesUnaligned(P, 4);
281 : P += 4;
282 : uint8_t *Ret = P + Length;
283 : uint32_t Offset = readBytesUnaligned(P, 4);
284 : if (Offset == 0) // is a CIE
285 1 : return Ret;
286 1 :
287 : P += 4;
288 : TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
289 : TargetPtrT NewLocation = FDELocation - DeltaForText;
290 0 : writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
291 :
292 0 : P += sizeof(TargetPtrT);
293 :
294 : // Skip the FDE address range
295 : P += sizeof(TargetPtrT);
296 0 :
297 : uint8_t Augmentationsize = *P;
298 0 : P += 1;
299 : if (Augmentationsize != 0) {
300 : TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
301 : TargetPtrT NewLSDA = LSDA - DeltaForEH;
302 : writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
303 : }
304 :
305 : return Ret;
306 : }
307 :
308 2 : static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
309 : int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
310 : static_cast<int64_t>(B->getObjAddress());
311 : int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
312 : return ObjDistance - MemDistance;
313 2 : }
314 :
315 : template <typename Impl>
316 : void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
317 :
318 : for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
319 6 : EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
320 4 : if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
321 4 : SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
322 : continue;
323 : SectionEntry *Text = &Sections[SectionInfo.TextSID];
324 : SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
325 : SectionEntry *ExceptTab = nullptr;
326 : if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
327 2 : ExceptTab = &Sections[SectionInfo.ExceptTabSID];
328 2 :
329 : int64_t DeltaForText = computeDelta(Text, EHFrame);
330 : int64_t DeltaForEH = 0;
331 : if (ExceptTab)
332 0 : DeltaForEH = computeDelta(ExceptTab, EHFrame);
333 :
334 0 : uint8_t *P = EHFrame->getAddress();
335 : uint8_t *End = P + EHFrame->getSize();
336 : while (P != End) {
337 : P = processFDE(P, DeltaForText, DeltaForEH);
338 0 : }
339 :
340 0 : MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
341 : EHFrame->getSize());
342 : }
343 : UnregisteredEHFrameSections.clear();
344 : }
345 2 :
346 4 : std::unique_ptr<RuntimeDyldMachO>
347 : RuntimeDyldMachO::create(Triple::ArchType Arch,
348 : RuntimeDyld::MemoryManager &MemMgr,
349 : JITSymbolResolver &Resolver) {
350 4 : switch (Arch) {
351 : default:
352 : llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
353 : break;
354 : case Triple::arm:
355 2 : return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
356 : case Triple::aarch64:
357 : return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
358 : case Triple::x86:
359 : return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
360 : case Triple::x86_64:
361 9 : return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
362 7 : }
363 7 : }
364 :
365 : std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
366 : RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
367 : if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
368 : return llvm::make_unique<LoadedMachOObjectInfo>(*this,
369 2 : *ObjSectionToIDOrErr);
370 2 : else {
371 : HasError = true;
372 : raw_string_ostream ErrStream(ErrorStr);
373 : logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, "");
374 1 : return nullptr;
375 : }
376 1 : }
377 :
378 : } // end namespace llvm
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