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
30 : public RuntimeDyld::LoadedObjectInfoHelper<LoadedMachOObjectInfo> {
32 LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld, unsigned BeginIdx,
34 : LoadedObjectInfoHelper(RTDyld, BeginIdx, EndIdx) {}
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 RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
54 const ObjectFile &BaseTObj, const relocation_iterator &RI,
55 const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
57 const MachOObjectFile &Obj =
58 static_cast<const MachOObjectFile &>(BaseTObj);
59 MachO::any_relocation_info RelInfo =
60 Obj.getRelocation(RI->getRawDataRefImpl());
61 RelocationValueRef Value;
63 bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
65 symbol_iterator Symbol = RI->getSymbol();
66 ErrorOr<StringRef> TargetNameOrErr = Symbol->getName();
67 if (std::error_code EC = TargetNameOrErr.getError())
68 report_fatal_error(EC.message());
69 StringRef TargetName = *TargetNameOrErr;
70 RTDyldSymbolTable::const_iterator SI =
71 GlobalSymbolTable.find(TargetName.data());
72 if (SI != GlobalSymbolTable.end()) {
73 const auto &SymInfo = SI->second;
74 Value.SectionID = SymInfo.getSectionID();
75 Value.Offset = SymInfo.getOffset() + RE.Addend;
77 Value.SymbolName = TargetName.data();
78 Value.Offset = RE.Addend;
81 SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
82 bool IsCode = Sec.isText();
83 Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
84 uint64_t Addr = Sec.getAddress();
85 Value.Offset = RE.Addend - Addr;
91 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
92 const relocation_iterator &RI,
93 unsigned OffsetToNextPC) {
94 auto &O = *cast<MachOObjectFile>(RI->getObject());
95 section_iterator SecI = O.getRelocationRelocatedSection(RI);
96 Value.Offset += RI->getOffset() + OffsetToNextPC + SecI->getAddress();
99 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
100 uint64_t Value) const {
101 const SectionEntry &Section = Sections[RE.SectionID];
102 uint8_t *LocalAddress = Section.Address + RE.Offset;
103 uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
105 dbgs() << "resolveRelocation Section: " << RE.SectionID
106 << " LocalAddress: " << format("%p", LocalAddress)
107 << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
108 << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
109 << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
110 << " Size: " << (1 << RE.Size) << "\n";
114 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
116 section_iterator SI = Obj.section_begin();
117 section_iterator SE = Obj.section_end();
119 for (; SI != SE; ++SI) {
120 uint64_t SAddr = SI->getAddress();
121 uint64_t SSize = SI->getSize();
122 if ((Addr >= SAddr) && (Addr < SAddr + SSize))
130 // Populate __pointers section.
131 void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
132 const MachOObjectFile &Obj,
133 const SectionRef &PTSection,
134 unsigned PTSectionID) {
135 assert(!Obj.is64Bit() &&
136 "Pointer table section not supported in 64-bit MachO.");
138 MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
139 MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
140 uint32_t PTSectionSize = Sec32.size;
141 unsigned FirstIndirectSymbol = Sec32.reserved1;
142 const unsigned PTEntrySize = 4;
143 unsigned NumPTEntries = PTSectionSize / PTEntrySize;
144 unsigned PTEntryOffset = 0;
146 assert((PTSectionSize % PTEntrySize) == 0 &&
147 "Pointers section does not contain a whole number of stubs?");
149 DEBUG(dbgs() << "Populating pointer table section "
150 << Sections[PTSectionID].Name
151 << ", Section ID " << PTSectionID << ", "
152 << NumPTEntries << " entries, " << PTEntrySize
153 << " bytes each:\n");
155 for (unsigned i = 0; i < NumPTEntries; ++i) {
156 unsigned SymbolIndex =
157 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
158 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
159 ErrorOr<StringRef> IndirectSymbolNameOrErr = SI->getName();
160 if (std::error_code EC = IndirectSymbolNameOrErr.getError())
161 report_fatal_error(EC.message());
162 StringRef IndirectSymbolName = *IndirectSymbolNameOrErr;
163 DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
164 << ", PT offset: " << PTEntryOffset << "\n");
165 RelocationEntry RE(PTSectionID, PTEntryOffset,
166 MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
167 addRelocationForSymbol(RE, IndirectSymbolName);
168 PTEntryOffset += PTEntrySize;
172 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
173 return Obj.isMachO();
176 template <typename Impl>
177 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
178 ObjSectionToIDMap &SectionMap) {
179 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
180 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
181 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
183 for (const auto &Section : Obj.sections()) {
185 Section.getName(Name);
187 // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
188 // if they're present. Otherwise call down to the impl to handle other
189 // sections that have already been emitted.
190 if (Name == "__text")
191 TextSID = findOrEmitSection(Obj, Section, true, SectionMap);
192 else if (Name == "__eh_frame")
193 EHFrameSID = findOrEmitSection(Obj, Section, false, SectionMap);
194 else if (Name == "__gcc_except_tab")
195 ExceptTabSID = findOrEmitSection(Obj, Section, true, SectionMap);
197 auto I = SectionMap.find(Section);
198 if (I != SectionMap.end())
199 impl().finalizeSection(Obj, I->second, Section);
202 UnregisteredEHFrameSections.push_back(
203 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
206 template <typename Impl>
207 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
208 int64_t DeltaForText,
209 int64_t DeltaForEH) {
210 typedef typename Impl::TargetPtrT TargetPtrT;
212 DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
213 << ", Delta for EH: " << DeltaForEH << "\n");
214 uint32_t Length = readBytesUnaligned(P, 4);
216 unsigned char *Ret = P + Length;
217 uint32_t Offset = readBytesUnaligned(P, 4);
218 if (Offset == 0) // is a CIE
222 TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
223 TargetPtrT NewLocation = FDELocation - DeltaForText;
224 writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
226 P += sizeof(TargetPtrT);
228 // Skip the FDE address range
229 P += sizeof(TargetPtrT);
231 uint8_t Augmentationsize = *P;
233 if (Augmentationsize != 0) {
234 TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
235 TargetPtrT NewLSDA = LSDA - DeltaForEH;
236 writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
242 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
243 int64_t ObjDistance =
244 static_cast<int64_t>(A->ObjAddress) - static_cast<int64_t>(B->ObjAddress);
245 int64_t MemDistance = A->LoadAddress - B->LoadAddress;
246 return ObjDistance - MemDistance;
249 template <typename Impl>
250 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
252 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
253 EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
254 if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
255 SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
257 SectionEntry *Text = &Sections[SectionInfo.TextSID];
258 SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
259 SectionEntry *ExceptTab = nullptr;
260 if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
261 ExceptTab = &Sections[SectionInfo.ExceptTabSID];
263 int64_t DeltaForText = computeDelta(Text, EHFrame);
264 int64_t DeltaForEH = 0;
266 DeltaForEH = computeDelta(ExceptTab, EHFrame);
268 unsigned char *P = EHFrame->Address;
269 unsigned char *End = P + EHFrame->Size;
271 P = processFDE(P, DeltaForText, DeltaForEH);
274 MemMgr.registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
277 UnregisteredEHFrameSections.clear();
280 std::unique_ptr<RuntimeDyldMachO>
281 RuntimeDyldMachO::create(Triple::ArchType Arch,
282 RuntimeDyld::MemoryManager &MemMgr,
283 RuntimeDyld::SymbolResolver &Resolver) {
286 llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
289 return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
290 case Triple::aarch64:
291 return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
293 return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
295 return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
299 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
300 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
301 unsigned SectionStartIdx, SectionEndIdx;
302 std::tie(SectionStartIdx, SectionEndIdx) = loadObjectImpl(O);
303 return llvm::make_unique<LoadedMachOObjectInfo>(*this, SectionStartIdx,
307 } // end namespace llvm