1 //===-- RuntimeDyldMachO.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-=//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // Implementation of the MC-JIT runtime dynamic linker.
12 //===----------------------------------------------------------------------===//
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"
23 using namespace llvm::object;
25 #define DEBUG_TYPE "dyld"
29 class LoadedMachOObjectInfo final
30 : public RuntimeDyld::LoadedObjectInfoHelper<LoadedMachOObjectInfo> {
32 LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld,
33 ObjSectionToIDMap ObjSecToIDMap)
34 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
36 OwningBinary<ObjectFile>
37 getObjectForDebug(const ObjectFile &Obj) const override {
38 return OwningBinary<ObjectFile>();
46 int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
47 unsigned NumBytes = 1 << RE.Size;
48 uint8_t *Src = Sections[RE.SectionID].Address + RE.Offset;
50 return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
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());
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.Address + Offset;
68 unsigned NumBytes = 1 << Size;
69 int64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);
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);
80 Addend -= SectionBaseAddr;
81 RelocationEntry R(SectionID, Offset, RelocType, Addend, IsPCRel, Size);
83 addRelocationForSection(R, TargetSectionID);
89 RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
90 const ObjectFile &BaseTObj, const relocation_iterator &RI,
91 const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
93 const MachOObjectFile &Obj =
94 static_cast<const MachOObjectFile &>(BaseTObj);
95 MachO::any_relocation_info RelInfo =
96 Obj.getRelocation(RI->getRawDataRefImpl());
97 RelocationValueRef Value;
99 bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
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;
113 Value.SymbolName = TargetName.data();
114 Value.Offset = RE.Addend;
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;
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();
135 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
136 uint64_t Value) const {
137 const SectionEntry &Section = Sections[RE.SectionID];
138 uint8_t *LocalAddress = Section.Address + RE.Offset;
139 uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
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";
150 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
152 section_iterator SI = Obj.section_begin();
153 section_iterator SE = Obj.section_end();
155 for (; SI != SE; ++SI) {
156 uint64_t SAddr = SI->getAddress();
157 uint64_t SSize = SI->getSize();
158 if ((Addr >= SAddr) && (Addr < SAddr + SSize))
166 // Populate __pointers section.
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.");
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;
182 assert((PTSectionSize % PTEntrySize) == 0 &&
183 "Pointers section does not contain a whole number of stubs?");
185 DEBUG(dbgs() << "Populating pointer table section "
186 << Sections[PTSectionID].Name
187 << ", Section ID " << PTSectionID << ", "
188 << NumPTEntries << " entries, " << PTEntrySize
189 << " bytes each:\n");
191 for (unsigned i = 0; i < NumPTEntries; ++i) {
192 unsigned SymbolIndex =
193 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
194 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
195 ErrorOr<StringRef> IndirectSymbolNameOrErr = SI->getName();
196 if (std::error_code EC = IndirectSymbolNameOrErr.getError())
197 report_fatal_error(EC.message());
198 StringRef IndirectSymbolName = *IndirectSymbolNameOrErr;
199 DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
200 << ", PT offset: " << PTEntryOffset << "\n");
201 RelocationEntry RE(PTSectionID, PTEntryOffset,
202 MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
203 addRelocationForSymbol(RE, IndirectSymbolName);
204 PTEntryOffset += PTEntrySize;
208 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
209 return Obj.isMachO();
212 template <typename Impl>
213 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
214 ObjSectionToIDMap &SectionMap) {
215 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
216 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
217 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
219 for (const auto &Section : Obj.sections()) {
221 Section.getName(Name);
223 // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
224 // if they're present. Otherwise call down to the impl to handle other
225 // sections that have already been emitted.
226 if (Name == "__text")
227 TextSID = findOrEmitSection(Obj, Section, true, SectionMap);
228 else if (Name == "__eh_frame")
229 EHFrameSID = findOrEmitSection(Obj, Section, false, SectionMap);
230 else if (Name == "__gcc_except_tab")
231 ExceptTabSID = findOrEmitSection(Obj, Section, true, SectionMap);
233 auto I = SectionMap.find(Section);
234 if (I != SectionMap.end())
235 impl().finalizeSection(Obj, I->second, Section);
238 UnregisteredEHFrameSections.push_back(
239 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
242 template <typename Impl>
243 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
244 int64_t DeltaForText,
245 int64_t DeltaForEH) {
246 typedef typename Impl::TargetPtrT TargetPtrT;
248 DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
249 << ", Delta for EH: " << DeltaForEH << "\n");
250 uint32_t Length = readBytesUnaligned(P, 4);
252 unsigned char *Ret = P + Length;
253 uint32_t Offset = readBytesUnaligned(P, 4);
254 if (Offset == 0) // is a CIE
258 TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
259 TargetPtrT NewLocation = FDELocation - DeltaForText;
260 writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
262 P += sizeof(TargetPtrT);
264 // Skip the FDE address range
265 P += sizeof(TargetPtrT);
267 uint8_t Augmentationsize = *P;
269 if (Augmentationsize != 0) {
270 TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
271 TargetPtrT NewLSDA = LSDA - DeltaForEH;
272 writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
278 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
279 int64_t ObjDistance =
280 static_cast<int64_t>(A->ObjAddress) - static_cast<int64_t>(B->ObjAddress);
281 int64_t MemDistance = A->LoadAddress - B->LoadAddress;
282 return ObjDistance - MemDistance;
285 template <typename Impl>
286 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
288 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
289 EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
290 if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
291 SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
293 SectionEntry *Text = &Sections[SectionInfo.TextSID];
294 SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
295 SectionEntry *ExceptTab = nullptr;
296 if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
297 ExceptTab = &Sections[SectionInfo.ExceptTabSID];
299 int64_t DeltaForText = computeDelta(Text, EHFrame);
300 int64_t DeltaForEH = 0;
302 DeltaForEH = computeDelta(ExceptTab, EHFrame);
304 unsigned char *P = EHFrame->Address;
305 unsigned char *End = P + EHFrame->Size;
307 P = processFDE(P, DeltaForText, DeltaForEH);
310 MemMgr.registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
313 UnregisteredEHFrameSections.clear();
316 std::unique_ptr<RuntimeDyldMachO>
317 RuntimeDyldMachO::create(Triple::ArchType Arch,
318 RuntimeDyld::MemoryManager &MemMgr,
319 RuntimeDyld::SymbolResolver &Resolver) {
322 llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
325 return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
326 case Triple::aarch64:
327 return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
329 return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
331 return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
335 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
336 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
337 return llvm::make_unique<LoadedMachOObjectInfo>(*this, loadObjectImpl(O));
340 } // end namespace llvm