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 "llvm/ADT/STLExtras.h"
16 #include "llvm/ADT/StringRef.h"
18 #include "Targets/RuntimeDyldMachOARM.h"
19 #include "Targets/RuntimeDyldMachOAArch64.h"
20 #include "Targets/RuntimeDyldMachOI386.h"
21 #include "Targets/RuntimeDyldMachOX86_64.h"
24 using namespace llvm::object;
26 #define DEBUG_TYPE "dyld"
30 int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
31 unsigned NumBytes = 1 << RE.Size;
32 uint8_t *Src = Sections[RE.SectionID].Address + RE.Offset;
34 return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
37 RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
38 ObjectImage &ObjImg, const relocation_iterator &RI,
39 const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID,
40 const SymbolTableMap &Symbols) {
42 const MachOObjectFile &Obj =
43 static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
44 MachO::any_relocation_info RelInfo =
45 Obj.getRelocation(RI->getRawDataRefImpl());
46 RelocationValueRef Value;
48 bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
50 symbol_iterator Symbol = RI->getSymbol();
52 Symbol->getName(TargetName);
53 SymbolTableMap::const_iterator SI = Symbols.find(TargetName.data());
54 if (SI != Symbols.end()) {
55 Value.SectionID = SI->second.first;
56 Value.Offset = SI->second.second + RE.Addend;
58 SI = GlobalSymbolTable.find(TargetName.data());
59 if (SI != GlobalSymbolTable.end()) {
60 Value.SectionID = SI->second.first;
61 Value.Offset = SI->second.second + RE.Addend;
63 Value.SymbolName = TargetName.data();
64 Value.Offset = RE.Addend;
68 SectionRef Sec = Obj.getRelocationSection(RelInfo);
69 bool IsCode = Sec.isText();
70 Value.SectionID = findOrEmitSection(ObjImg, Sec, IsCode, ObjSectionToID);
71 uint64_t Addr = Sec.getAddress();
72 Value.Offset = RE.Addend - Addr;
78 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
80 const relocation_iterator &RI,
81 unsigned OffsetToNextPC) {
82 const MachOObjectFile &Obj =
83 static_cast<const MachOObjectFile &>(*ObjImg.getObjectFile());
84 MachO::any_relocation_info RelInfo =
85 Obj.getRelocation(RI->getRawDataRefImpl());
87 bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
89 uint64_t RelocAddr = 0;
90 RI->getAddress(RelocAddr);
91 Value.Offset += RelocAddr + OffsetToNextPC;
95 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
96 uint64_t Value) const {
97 const SectionEntry &Section = Sections[RE.SectionID];
98 uint8_t *LocalAddress = Section.Address + RE.Offset;
99 uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
101 dbgs() << "resolveRelocation Section: " << RE.SectionID
102 << " LocalAddress: " << format("%p", LocalAddress)
103 << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
104 << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
105 << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
106 << " Size: " << (1 << RE.Size) << "\n";
110 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
112 section_iterator SI = Obj.section_begin();
113 section_iterator SE = Obj.section_end();
115 for (; SI != SE; ++SI) {
116 uint64_t SAddr = SI->getAddress();
117 uint64_t SSize = SI->getSize();
118 if ((Addr >= SAddr) && (Addr < SAddr + SSize))
126 // Populate __pointers section.
127 void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
128 MachOObjectFile &Obj,
129 const SectionRef &PTSection,
130 unsigned PTSectionID) {
131 assert(!Obj.is64Bit() &&
132 "Pointer table section not supported in 64-bit MachO.");
134 MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
135 MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
136 uint32_t PTSectionSize = Sec32.size;
137 unsigned FirstIndirectSymbol = Sec32.reserved1;
138 const unsigned PTEntrySize = 4;
139 unsigned NumPTEntries = PTSectionSize / PTEntrySize;
140 unsigned PTEntryOffset = 0;
142 assert((PTSectionSize % PTEntrySize) == 0 &&
143 "Pointers section does not contain a whole number of stubs?");
145 DEBUG(dbgs() << "Populating pointer table section "
146 << Sections[PTSectionID].Name
147 << ", Section ID " << PTSectionID << ", "
148 << NumPTEntries << " entries, " << PTEntrySize
149 << " bytes each:\n");
151 for (unsigned i = 0; i < NumPTEntries; ++i) {
152 unsigned SymbolIndex =
153 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
154 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
155 StringRef IndirectSymbolName;
156 SI->getName(IndirectSymbolName);
157 DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
158 << ", PT offset: " << PTEntryOffset << "\n");
159 RelocationEntry RE(PTSectionID, PTEntryOffset,
160 MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
161 addRelocationForSymbol(RE, IndirectSymbolName);
162 PTEntryOffset += PTEntrySize;
167 RuntimeDyldMachO::isCompatibleFormat(const ObjectBuffer *InputBuffer) const {
168 if (InputBuffer->getBufferSize() < 4)
170 StringRef Magic(InputBuffer->getBufferStart(), 4);
171 if (Magic == "\xFE\xED\xFA\xCE")
173 if (Magic == "\xCE\xFA\xED\xFE")
175 if (Magic == "\xFE\xED\xFA\xCF")
177 if (Magic == "\xCF\xFA\xED\xFE")
182 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile *Obj) const {
183 return Obj->isMachO();
186 template <typename Impl>
187 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(ObjectImage &ObjImg,
188 ObjSectionToIDMap &SectionMap) {
189 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
190 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
191 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
192 ObjSectionToIDMap::iterator i, e;
194 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
195 const SectionRef &Section = i->first;
197 Section.getName(Name);
198 if (Name == "__eh_frame")
199 EHFrameSID = i->second;
200 else if (Name == "__text")
202 else if (Name == "__gcc_except_tab")
203 ExceptTabSID = i->second;
205 impl().finalizeSection(ObjImg, i->second, Section);
207 UnregisteredEHFrameSections.push_back(
208 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
211 template <typename Impl>
212 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
213 int64_t DeltaForText,
214 int64_t DeltaForEH) {
215 typedef typename Impl::TargetPtrT TargetPtrT;
217 DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
218 << ", Delta for EH: " << DeltaForEH << "\n");
219 uint32_t Length = readBytesUnaligned(P, 4);
221 unsigned char *Ret = P + Length;
222 uint32_t Offset = readBytesUnaligned(P, 4);
223 if (Offset == 0) // is a CIE
227 TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
228 TargetPtrT NewLocation = FDELocation - DeltaForText;
229 writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
231 P += sizeof(TargetPtrT);
233 // Skip the FDE address range
234 P += sizeof(TargetPtrT);
236 uint8_t Augmentationsize = *P;
238 if (Augmentationsize != 0) {
239 TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
240 TargetPtrT NewLSDA = LSDA - DeltaForEH;
241 writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
247 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
248 int64_t ObjDistance = A->ObjAddress - B->ObjAddress;
249 int64_t MemDistance = A->LoadAddress - B->LoadAddress;
250 return ObjDistance - MemDistance;
253 template <typename Impl>
254 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
258 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
259 EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
260 if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
261 SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
263 SectionEntry *Text = &Sections[SectionInfo.TextSID];
264 SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
265 SectionEntry *ExceptTab = nullptr;
266 if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
267 ExceptTab = &Sections[SectionInfo.ExceptTabSID];
269 int64_t DeltaForText = computeDelta(Text, EHFrame);
270 int64_t DeltaForEH = 0;
272 DeltaForEH = computeDelta(ExceptTab, EHFrame);
274 unsigned char *P = EHFrame->Address;
275 unsigned char *End = P + EHFrame->Size;
277 P = processFDE(P, DeltaForText, DeltaForEH);
280 MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
283 UnregisteredEHFrameSections.clear();
286 std::unique_ptr<RuntimeDyldMachO>
287 llvm::RuntimeDyldMachO::create(Triple::ArchType Arch, RTDyldMemoryManager *MM) {
290 llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
292 case Triple::arm: return make_unique<RuntimeDyldMachOARM>(MM);
293 case Triple::aarch64: return make_unique<RuntimeDyldMachOAArch64>(MM);
294 case Triple::x86: return make_unique<RuntimeDyldMachOI386>(MM);
295 case Triple::x86_64: return make_unique<RuntimeDyldMachOX86_64>(MM);
299 } // end namespace llvm