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();
67 Symbol->getName(TargetName);
68 RTDyldSymbolTable::const_iterator SI =
69 GlobalSymbolTable.find(TargetName.data());
70 if (SI != GlobalSymbolTable.end()) {
71 const auto &SymInfo = SI->second;
72 Value.SectionID = SymInfo.getSectionID();
73 Value.Offset = SymInfo.getOffset() + RE.Addend;
75 Value.SymbolName = TargetName.data();
76 Value.Offset = RE.Addend;
79 SectionRef Sec = Obj.getAnyRelocationSection(RelInfo);
80 bool IsCode = Sec.isText();
81 Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
82 uint64_t Addr = Sec.getAddress();
83 Value.Offset = RE.Addend - Addr;
89 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
90 const ObjectFile &BaseTObj,
91 const relocation_iterator &RI,
92 unsigned OffsetToNextPC) {
93 const MachOObjectFile &Obj =
94 static_cast<const MachOObjectFile &>(BaseTObj);
95 MachO::any_relocation_info RelInfo =
96 Obj.getRelocation(RI->getRawDataRefImpl());
98 bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
100 ErrorOr<uint64_t> RelocAddr = RI->getAddress();
101 Value.Offset += *RelocAddr + OffsetToNextPC;
105 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
106 uint64_t Value) const {
107 const SectionEntry &Section = Sections[RE.SectionID];
108 uint8_t *LocalAddress = Section.Address + RE.Offset;
109 uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
111 dbgs() << "resolveRelocation Section: " << RE.SectionID
112 << " LocalAddress: " << format("%p", LocalAddress)
113 << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
114 << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
115 << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
116 << " Size: " << (1 << RE.Size) << "\n";
120 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
122 section_iterator SI = Obj.section_begin();
123 section_iterator SE = Obj.section_end();
125 for (; SI != SE; ++SI) {
126 uint64_t SAddr = SI->getAddress();
127 uint64_t SSize = SI->getSize();
128 if ((Addr >= SAddr) && (Addr < SAddr + SSize))
136 // Populate __pointers section.
137 void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
138 const MachOObjectFile &Obj,
139 const SectionRef &PTSection,
140 unsigned PTSectionID) {
141 assert(!Obj.is64Bit() &&
142 "Pointer table section not supported in 64-bit MachO.");
144 MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
145 MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
146 uint32_t PTSectionSize = Sec32.size;
147 unsigned FirstIndirectSymbol = Sec32.reserved1;
148 const unsigned PTEntrySize = 4;
149 unsigned NumPTEntries = PTSectionSize / PTEntrySize;
150 unsigned PTEntryOffset = 0;
152 assert((PTSectionSize % PTEntrySize) == 0 &&
153 "Pointers section does not contain a whole number of stubs?");
155 DEBUG(dbgs() << "Populating pointer table section "
156 << Sections[PTSectionID].Name
157 << ", Section ID " << PTSectionID << ", "
158 << NumPTEntries << " entries, " << PTEntrySize
159 << " bytes each:\n");
161 for (unsigned i = 0; i < NumPTEntries; ++i) {
162 unsigned SymbolIndex =
163 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
164 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
165 StringRef IndirectSymbolName;
166 SI->getName(IndirectSymbolName);
167 DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
168 << ", PT offset: " << PTEntryOffset << "\n");
169 RelocationEntry RE(PTSectionID, PTEntryOffset,
170 MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
171 addRelocationForSymbol(RE, IndirectSymbolName);
172 PTEntryOffset += PTEntrySize;
176 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
177 return Obj.isMachO();
180 template <typename Impl>
181 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
182 ObjSectionToIDMap &SectionMap) {
183 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
184 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
185 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
187 for (const auto &Section : Obj.sections()) {
189 Section.getName(Name);
191 // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
192 // if they're present. Otherwise call down to the impl to handle other
193 // sections that have already been emitted.
194 if (Name == "__text")
195 TextSID = findOrEmitSection(Obj, Section, true, SectionMap);
196 else if (Name == "__eh_frame")
197 EHFrameSID = findOrEmitSection(Obj, Section, false, SectionMap);
198 else if (Name == "__gcc_except_tab")
199 ExceptTabSID = findOrEmitSection(Obj, Section, true, SectionMap);
201 auto I = SectionMap.find(Section);
202 if (I != SectionMap.end())
203 impl().finalizeSection(Obj, I->second, Section);
206 UnregisteredEHFrameSections.push_back(
207 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
210 template <typename Impl>
211 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
212 int64_t DeltaForText,
213 int64_t DeltaForEH) {
214 typedef typename Impl::TargetPtrT TargetPtrT;
216 DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
217 << ", Delta for EH: " << DeltaForEH << "\n");
218 uint32_t Length = readBytesUnaligned(P, 4);
220 unsigned char *Ret = P + Length;
221 uint32_t Offset = readBytesUnaligned(P, 4);
222 if (Offset == 0) // is a CIE
226 TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
227 TargetPtrT NewLocation = FDELocation - DeltaForText;
228 writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
230 P += sizeof(TargetPtrT);
232 // Skip the FDE address range
233 P += sizeof(TargetPtrT);
235 uint8_t Augmentationsize = *P;
237 if (Augmentationsize != 0) {
238 TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
239 TargetPtrT NewLSDA = LSDA - DeltaForEH;
240 writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
246 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
247 int64_t ObjDistance =
248 static_cast<int64_t>(A->ObjAddress) - static_cast<int64_t>(B->ObjAddress);
249 int64_t MemDistance = A->LoadAddress - B->LoadAddress;
250 return ObjDistance - MemDistance;
253 template <typename Impl>
254 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
256 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
257 EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
258 if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
259 SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
261 SectionEntry *Text = &Sections[SectionInfo.TextSID];
262 SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
263 SectionEntry *ExceptTab = nullptr;
264 if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
265 ExceptTab = &Sections[SectionInfo.ExceptTabSID];
267 int64_t DeltaForText = computeDelta(Text, EHFrame);
268 int64_t DeltaForEH = 0;
270 DeltaForEH = computeDelta(ExceptTab, EHFrame);
272 unsigned char *P = EHFrame->Address;
273 unsigned char *End = P + EHFrame->Size;
275 P = processFDE(P, DeltaForText, DeltaForEH);
278 MemMgr.registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
281 UnregisteredEHFrameSections.clear();
284 std::unique_ptr<RuntimeDyldMachO>
285 RuntimeDyldMachO::create(Triple::ArchType Arch,
286 RuntimeDyld::MemoryManager &MemMgr,
287 RuntimeDyld::SymbolResolver &Resolver) {
290 llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
293 return make_unique<RuntimeDyldMachOARM>(MemMgr, Resolver);
294 case Triple::aarch64:
295 return make_unique<RuntimeDyldMachOAArch64>(MemMgr, Resolver);
297 return make_unique<RuntimeDyldMachOI386>(MemMgr, Resolver);
299 return make_unique<RuntimeDyldMachOX86_64>(MemMgr, Resolver);
303 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
304 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
305 unsigned SectionStartIdx, SectionEndIdx;
306 std::tie(SectionStartIdx, SectionEndIdx) = loadObjectImpl(O);
307 return llvm::make_unique<LoadedMachOObjectInfo>(*this, SectionStartIdx,
311 } // end namespace llvm