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
processScatteredVANILLA(unsigned SectionID,relocation_iterator RelI,const ObjectFile & BaseObjT,RuntimeDyldMachO::ObjSectionToIDMap & ObjSectionToID)53 relocation_iterator RuntimeDyldMachO::processScatteredVANILLA(
54 unsigned SectionID, relocation_iterator RelI,
55 const ObjectFile &BaseObjT,
56 RuntimeDyldMachO::ObjSectionToIDMap &ObjSectionToID) {
57 const MachOObjectFile &Obj =
58 static_cast<const MachOObjectFile&>(BaseObjT);
59 MachO::any_relocation_info RE =
60 Obj.getRelocation(RelI->getRawDataRefImpl());
61
62 SectionEntry &Section = Sections[SectionID];
63 uint32_t RelocType = Obj.getAnyRelocationType(RE);
64 bool IsPCRel = Obj.getAnyRelocationPCRel(RE);
65 unsigned Size = Obj.getAnyRelocationLength(RE);
66 uint64_t Offset = RelI->getOffset();
67 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
68 unsigned NumBytes = 1 << Size;
69 int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
70
71 unsigned SymbolBaseAddr = Obj.getScatteredRelocationValue(RE);
72 section_iterator TargetSI = getSectionByAddress(Obj, SymbolBaseAddr);
73 assert(TargetSI != Obj.section_end() && "Can't find section for symbol");
74 uint64_t SectionBaseAddr = TargetSI->getAddress();
75 SectionRef TargetSection = *TargetSI;
76 bool IsCode = TargetSection.isText();
77 uint32_t TargetSectionID =
78 findOrEmitSection(Obj, TargetSection, IsCode, ObjSectionToID);
79
80 Addend -= SectionBaseAddr;
81 RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
82
83 addRelocationForSection(R, TargetSectionID);
84
85 return ++RelI;
86 }
87
88
getRelocationValueRef(const ObjectFile & BaseTObj,const relocation_iterator & RI,const RelocationEntry & RE,ObjSectionToIDMap & ObjSectionToID)89 RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
90 const ObjectFile &BaseTObj, const relocation_iterator &RI,
91 const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
92
93 const MachOObjectFile &Obj =
94 static_cast<const MachOObjectFile &>(BaseTObj);
95 MachO::any_relocation_info RelInfo =
96 Obj.getRelocation(RI->getRawDataRefImpl());
97 RelocationValueRef Value;
98
99 bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
100 if (IsExternal) {
101 symbol_iterator Symbol = RI->getSymbol();
102 ErrorOr<StringRef> TargetNameOrErr = Symbol->getName();
103 if (std::error_code EC = TargetNameOrErr.getError())
104 report_fatal_error(EC.message());
105 StringRef TargetName = *TargetNameOrErr;
106 RTDyldSymbolTable::const_iterator SI =
107 GlobalSymbolTable.find(TargetName.data());
108 if (SI != GlobalSymbolTable.end()) {
109 const auto &SymInfo = SI->second;
110 Value.SectionID = SymInfo.getSectionID();
111 Value.Offset = SymInfo.getOffset() + RE.Addend;
112 } else {
113 Value.SymbolName = TargetName.data();
114 Value.Offset = RE.Addend;
115 }
116 } else {
117 SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
118 bool IsCode = Sec.isText();
119 Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
120 uint64_t Addr = Sec.getAddress();
121 Value.Offset = RE.Addend - Addr;
122 }
123
124 return Value;
125 }
126
makeValueAddendPCRel(RelocationValueRef & Value,const relocation_iterator & RI,unsigned OffsetToNextPC)127 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
128 const relocation_iterator &RI,
129 unsigned OffsetToNextPC) {
130 auto &O = *cast<MachOObjectFile>(RI->getObject());
131 section_iterator SecI = O.getRelocationRelocatedSection(RI);
132 Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
133 }
134
dumpRelocationToResolve(const RelocationEntry & RE,uint64_t Value) const135 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
136 uint64_t Value) const {
137 const SectionEntry &Section = Sections[RE.SectionID];
138 uint8_t *LocalAddress = Section.getAddress() + RE.Offset;
139 uint64_t FinalAddress = Section.getLoadAddress() + RE.Offset;
140
141 dbgs() << "resolveRelocation Section: " << RE.SectionID
142 << " LocalAddress: " << format("%p", LocalAddress)
143 << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
144 << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
145 << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
146 << " Size: " << (1 << RE.Size) << "\n";
147 }
148
149 section_iterator
getSectionByAddress(const MachOObjectFile & Obj,uint64_t Addr)150 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
151 uint64_t Addr) {
152 section_iterator SI = Obj.section_begin();
153 section_iterator SE = Obj.section_end();
154
155 for (; SI != SE; ++SI) {
156 uint64_t SAddr = SI->getAddress();
157 uint64_t SSize = SI->getSize();
158 if ((Addr >= SAddr) && (Addr < SAddr + SSize))
159 return SI;
160 }
161
162 return SE;
163 }
164
165
166 // Populate __pointers section.
populateIndirectSymbolPointersSection(const MachOObjectFile & Obj,const SectionRef & PTSection,unsigned PTSectionID)167 void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
168 const MachOObjectFile &Obj,
169 const SectionRef &PTSection,
170 unsigned PTSectionID) {
171 assert(!Obj.is64Bit() &&
172 "Pointer table section not supported in 64-bit MachO.");
173
174 MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
175 MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
176 uint32_t PTSectionSize = Sec32.size;
177 unsigned FirstIndirectSymbol = Sec32.reserved1;
178 const unsigned PTEntrySize = 4;
179 unsigned NumPTEntries = PTSectionSize / PTEntrySize;
180 unsigned PTEntryOffset = 0;
181
182 assert((PTSectionSize % PTEntrySize) == 0 &&
183 "Pointers section does not contain a whole number of stubs?");
184
185 DEBUG(dbgs() << "Populating pointer table section "
186 << Sections[PTSectionID].getName() << ", Section ID "
187 << PTSectionID << ", " << NumPTEntries << " entries, "
188 << PTEntrySize << " bytes each:\n");
189
190 for (unsigned i = 0; i < NumPTEntries; ++i) {
191 unsigned SymbolIndex =
192 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
193 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
194 ErrorOr<StringRef> IndirectSymbolNameOrErr = SI->getName();
195 if (std::error_code EC = IndirectSymbolNameOrErr.getError())
196 report_fatal_error(EC.message());
197 StringRef IndirectSymbolName = *IndirectSymbolNameOrErr;
198 DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
199 << ", PT offset: " << PTEntryOffset << "\n");
200 RelocationEntry RE(PTSectionID, PTEntryOffset,
201 MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
202 addRelocationForSymbol(RE, IndirectSymbolName);
203 PTEntryOffset += PTEntrySize;
204 }
205 }
206
isCompatibleFile(const object::ObjectFile & Obj) const207 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
208 return Obj.isMachO();
209 }
210
211 template <typename Impl>
finalizeLoad(const ObjectFile & Obj,ObjSectionToIDMap & SectionMap)212 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
213 ObjSectionToIDMap &SectionMap) {
214 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
215 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
216 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
217
218 for (const auto &Section : Obj.sections()) {
219 StringRef Name;
220 Section.getName(Name);
221
222 // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
223 // if they're present. Otherwise call down to the impl to handle other
224 // sections that have already been emitted.
225 if (Name == "__text")
226 TextSID = findOrEmitSection(Obj, Section, true, SectionMap);
227 else if (Name == "__eh_frame")
228 EHFrameSID = findOrEmitSection(Obj, Section, false, SectionMap);
229 else if (Name == "__gcc_except_tab")
230 ExceptTabSID = findOrEmitSection(Obj, Section, true, SectionMap);
231 else {
232 auto I = SectionMap.find(Section);
233 if (I != SectionMap.end())
234 impl().finalizeSection(Obj, I->second, Section);
235 }
236 }
237 UnregisteredEHFrameSections.push_back(
238 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
239 }
240
241 template <typename Impl>
processFDE(uint8_t * P,int64_t DeltaForText,int64_t DeltaForEH)242 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(uint8_t *P,
243 int64_t DeltaForText,
244 int64_t DeltaForEH) {
245 typedef typename Impl::TargetPtrT TargetPtrT;
246
247 DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
248 << ", Delta for EH: " << DeltaForEH << "\n");
249 uint32_t Length = readBytesUnaligned(P, 4);
250 P += 4;
251 uint8_t *Ret = P + Length;
252 uint32_t Offset = readBytesUnaligned(P, 4);
253 if (Offset == 0) // is a CIE
254 return Ret;
255
256 P += 4;
257 TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
258 TargetPtrT NewLocation = FDELocation - DeltaForText;
259 writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
260
261 P += sizeof(TargetPtrT);
262
263 // Skip the FDE address range
264 P += sizeof(TargetPtrT);
265
266 uint8_t Augmentationsize = *P;
267 P += 1;
268 if (Augmentationsize != 0) {
269 TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
270 TargetPtrT NewLSDA = LSDA - DeltaForEH;
271 writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
272 }
273
274 return Ret;
275 }
276
computeDelta(SectionEntry * A,SectionEntry * B)277 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
278 int64_t ObjDistance = static_cast<int64_t>(A->getObjAddress()) -
279 static_cast<int64_t>(B->getObjAddress());
280 int64_t MemDistance = A->getLoadAddress() - B->getLoadAddress();
281 return ObjDistance - MemDistance;
282 }
283
284 template <typename Impl>
registerEHFrames()285 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
286
287 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
288 EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
289 if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
290 SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
291 continue;
292 SectionEntry *Text = &Sections[SectionInfo.TextSID];
293 SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
294 SectionEntry *ExceptTab = nullptr;
295 if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
296 ExceptTab = &Sections[SectionInfo.ExceptTabSID];
297
298 int64_t DeltaForText = computeDelta(Text, EHFrame);
299 int64_t DeltaForEH = 0;
300 if (ExceptTab)
301 DeltaForEH = computeDelta(ExceptTab, EHFrame);
302
303 uint8_t *P = EHFrame->getAddress();
304 uint8_t *End = P + EHFrame->getSize();
305 do {
306 P = processFDE(P, DeltaForText, DeltaForEH);
307 } while (P != End);
308
309 MemMgr.registerEHFrames(EHFrame->getAddress(), EHFrame->getLoadAddress(),
310 EHFrame->getSize());
311 }
312 UnregisteredEHFrameSections.clear();
313 }
314
315 std::unique_ptr<RuntimeDyldMachO>
create(Triple::ArchType Arch,RuntimeDyld::MemoryManager & MemMgr,RuntimeDyld::SymbolResolver & Resolver)316 RuntimeDyldMachO::create(Triple::ArchType Arch,
317 RuntimeDyld::MemoryManager &MemMgr,
318 RuntimeDyld::SymbolResolver &Resolver) {
319 switch (Arch) {
320 default:
321 llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
322 break;
323 case Triple::arm:
324 return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
325 case Triple::aarch64:
326 return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
327 case Triple::x86:
328 return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
329 case Triple::x86_64:
330 return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
331 }
332 }
333
334 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
loadObject(const object::ObjectFile & O)335 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
336 return llvm::make_unique<LoadedMachOObjectInfo>(*this, loadObjectImpl(O));
337 }
338
339 } // end namespace llvm
340