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 : public RuntimeDyld::LoadedObjectInfo {
30 public:
LoadedMachOObjectInfo(RuntimeDyldImpl & RTDyld,unsigned BeginIdx,unsigned EndIdx)31 LoadedMachOObjectInfo(RuntimeDyldImpl &RTDyld, unsigned BeginIdx,
32 unsigned EndIdx)
33 : RuntimeDyld::LoadedObjectInfo(RTDyld, BeginIdx, EndIdx) {}
34
35 OwningBinary<ObjectFile>
getObjectForDebug(const ObjectFile & Obj) const36 getObjectForDebug(const ObjectFile &Obj) const override {
37 return OwningBinary<ObjectFile>();
38 }
39 };
40
41 }
42
43 namespace llvm {
44
memcpyAddend(const RelocationEntry & RE) const45 int64_t RuntimeDyldMachO::memcpyAddend(const RelocationEntry &RE) const {
46 unsigned NumBytes = 1 << RE.Size;
47 uint8_t *Src = Sections[RE.SectionID].Address + RE.Offset;
48
49 return static_cast<int64_t>(readBytesUnaligned(Src, NumBytes));
50 }
51
getRelocationValueRef(const ObjectFile & BaseTObj,const relocation_iterator & RI,const RelocationEntry & RE,ObjSectionToIDMap & ObjSectionToID)52 RelocationValueRef RuntimeDyldMachO::getRelocationValueRef(
53 const ObjectFile &BaseTObj, const relocation_iterator &RI,
54 const RelocationEntry &RE, ObjSectionToIDMap &ObjSectionToID) {
55
56 const MachOObjectFile &Obj =
57 static_cast<const MachOObjectFile &>(BaseTObj);
58 MachO::any_relocation_info RelInfo =
59 Obj.getRelocation(RI->getRawDataRefImpl());
60 RelocationValueRef Value;
61
62 bool IsExternal = Obj.getPlainRelocationExternal(RelInfo);
63 if (IsExternal) {
64 symbol_iterator Symbol = RI->getSymbol();
65 StringRef TargetName;
66 Symbol->getName(TargetName);
67 SymbolTableMap::const_iterator SI =
68 GlobalSymbolTable.find(TargetName.data());
69 if (SI != GlobalSymbolTable.end()) {
70 Value.SectionID = SI->second.first;
71 Value.Offset = SI->second.second + RE.Addend;
72 } else {
73 Value.SymbolName = TargetName.data();
74 Value.Offset = RE.Addend;
75 }
76 } else {
77 SectionRef Sec = Obj.getRelocationSection(RelInfo);
78 bool IsCode = Sec.isText();
79 Value.SectionID = findOrEmitSection(Obj, Sec, IsCode, ObjSectionToID);
80 uint64_t Addr = Sec.getAddress();
81 Value.Offset = RE.Addend - Addr;
82 }
83
84 return Value;
85 }
86
makeValueAddendPCRel(RelocationValueRef & Value,const ObjectFile & BaseTObj,const relocation_iterator & RI,unsigned OffsetToNextPC)87 void RuntimeDyldMachO::makeValueAddendPCRel(RelocationValueRef &Value,
88 const ObjectFile &BaseTObj,
89 const relocation_iterator &RI,
90 unsigned OffsetToNextPC) {
91 const MachOObjectFile &Obj =
92 static_cast<const MachOObjectFile &>(BaseTObj);
93 MachO::any_relocation_info RelInfo =
94 Obj.getRelocation(RI->getRawDataRefImpl());
95
96 bool IsPCRel = Obj.getAnyRelocationPCRel(RelInfo);
97 if (IsPCRel) {
98 uint64_t RelocAddr = 0;
99 RI->getAddress(RelocAddr);
100 Value.Offset += RelocAddr + OffsetToNextPC;
101 }
102 }
103
dumpRelocationToResolve(const RelocationEntry & RE,uint64_t Value) const104 void RuntimeDyldMachO::dumpRelocationToResolve(const RelocationEntry &RE,
105 uint64_t Value) const {
106 const SectionEntry &Section = Sections[RE.SectionID];
107 uint8_t *LocalAddress = Section.Address + RE.Offset;
108 uint64_t FinalAddress = Section.LoadAddress + RE.Offset;
109
110 dbgs() << "resolveRelocation Section: " << RE.SectionID
111 << " LocalAddress: " << format("%p", LocalAddress)
112 << " FinalAddress: " << format("0x%016" PRIx64, FinalAddress)
113 << " Value: " << format("0x%016" PRIx64, Value) << " Addend: " << RE.Addend
114 << " isPCRel: " << RE.IsPCRel << " MachoType: " << RE.RelType
115 << " Size: " << (1 << RE.Size) << "\n";
116 }
117
118 section_iterator
getSectionByAddress(const MachOObjectFile & Obj,uint64_t Addr)119 RuntimeDyldMachO::getSectionByAddress(const MachOObjectFile &Obj,
120 uint64_t Addr) {
121 section_iterator SI = Obj.section_begin();
122 section_iterator SE = Obj.section_end();
123
124 for (; SI != SE; ++SI) {
125 uint64_t SAddr = SI->getAddress();
126 uint64_t SSize = SI->getSize();
127 if ((Addr >= SAddr) && (Addr < SAddr + SSize))
128 return SI;
129 }
130
131 return SE;
132 }
133
134
135 // Populate __pointers section.
populateIndirectSymbolPointersSection(const MachOObjectFile & Obj,const SectionRef & PTSection,unsigned PTSectionID)136 void RuntimeDyldMachO::populateIndirectSymbolPointersSection(
137 const MachOObjectFile &Obj,
138 const SectionRef &PTSection,
139 unsigned PTSectionID) {
140 assert(!Obj.is64Bit() &&
141 "Pointer table section not supported in 64-bit MachO.");
142
143 MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();
144 MachO::section Sec32 = Obj.getSection(PTSection.getRawDataRefImpl());
145 uint32_t PTSectionSize = Sec32.size;
146 unsigned FirstIndirectSymbol = Sec32.reserved1;
147 const unsigned PTEntrySize = 4;
148 unsigned NumPTEntries = PTSectionSize / PTEntrySize;
149 unsigned PTEntryOffset = 0;
150
151 assert((PTSectionSize % PTEntrySize) == 0 &&
152 "Pointers section does not contain a whole number of stubs?");
153
154 DEBUG(dbgs() << "Populating pointer table section "
155 << Sections[PTSectionID].Name
156 << ", Section ID " << PTSectionID << ", "
157 << NumPTEntries << " entries, " << PTEntrySize
158 << " bytes each:\n");
159
160 for (unsigned i = 0; i < NumPTEntries; ++i) {
161 unsigned SymbolIndex =
162 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);
163 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);
164 StringRef IndirectSymbolName;
165 SI->getName(IndirectSymbolName);
166 DEBUG(dbgs() << " " << IndirectSymbolName << ": index " << SymbolIndex
167 << ", PT offset: " << PTEntryOffset << "\n");
168 RelocationEntry RE(PTSectionID, PTEntryOffset,
169 MachO::GENERIC_RELOC_VANILLA, 0, false, 2);
170 addRelocationForSymbol(RE, IndirectSymbolName);
171 PTEntryOffset += PTEntrySize;
172 }
173 }
174
isCompatibleFile(const object::ObjectFile & Obj) const175 bool RuntimeDyldMachO::isCompatibleFile(const object::ObjectFile &Obj) const {
176 return Obj.isMachO();
177 }
178
179 template <typename Impl>
finalizeLoad(const ObjectFile & Obj,ObjSectionToIDMap & SectionMap)180 void RuntimeDyldMachOCRTPBase<Impl>::finalizeLoad(const ObjectFile &Obj,
181 ObjSectionToIDMap &SectionMap) {
182 unsigned EHFrameSID = RTDYLD_INVALID_SECTION_ID;
183 unsigned TextSID = RTDYLD_INVALID_SECTION_ID;
184 unsigned ExceptTabSID = RTDYLD_INVALID_SECTION_ID;
185
186 for (const auto &Section : Obj.sections()) {
187 StringRef Name;
188 Section.getName(Name);
189
190 // Force emission of the __text, __eh_frame, and __gcc_except_tab sections
191 // if they're present. Otherwise call down to the impl to handle other
192 // sections that have already been emitted.
193 if (Name == "__text")
194 TextSID = findOrEmitSection(Obj, Section, true, SectionMap);
195 else if (Name == "__eh_frame")
196 EHFrameSID = findOrEmitSection(Obj, Section, false, SectionMap);
197 else if (Name == "__gcc_except_tab")
198 ExceptTabSID = findOrEmitSection(Obj, Section, true, SectionMap);
199 else {
200 auto I = SectionMap.find(Section);
201 if (I != SectionMap.end())
202 impl().finalizeSection(Obj, I->second, Section);
203 }
204 }
205 UnregisteredEHFrameSections.push_back(
206 EHFrameRelatedSections(EHFrameSID, TextSID, ExceptTabSID));
207 }
208
209 template <typename Impl>
processFDE(unsigned char * P,int64_t DeltaForText,int64_t DeltaForEH)210 unsigned char *RuntimeDyldMachOCRTPBase<Impl>::processFDE(unsigned char *P,
211 int64_t DeltaForText,
212 int64_t DeltaForEH) {
213 typedef typename Impl::TargetPtrT TargetPtrT;
214
215 DEBUG(dbgs() << "Processing FDE: Delta for text: " << DeltaForText
216 << ", Delta for EH: " << DeltaForEH << "\n");
217 uint32_t Length = readBytesUnaligned(P, 4);
218 P += 4;
219 unsigned char *Ret = P + Length;
220 uint32_t Offset = readBytesUnaligned(P, 4);
221 if (Offset == 0) // is a CIE
222 return Ret;
223
224 P += 4;
225 TargetPtrT FDELocation = readBytesUnaligned(P, sizeof(TargetPtrT));
226 TargetPtrT NewLocation = FDELocation - DeltaForText;
227 writeBytesUnaligned(NewLocation, P, sizeof(TargetPtrT));
228
229 P += sizeof(TargetPtrT);
230
231 // Skip the FDE address range
232 P += sizeof(TargetPtrT);
233
234 uint8_t Augmentationsize = *P;
235 P += 1;
236 if (Augmentationsize != 0) {
237 TargetPtrT LSDA = readBytesUnaligned(P, sizeof(TargetPtrT));
238 TargetPtrT NewLSDA = LSDA - DeltaForEH;
239 writeBytesUnaligned(NewLSDA, P, sizeof(TargetPtrT));
240 }
241
242 return Ret;
243 }
244
computeDelta(SectionEntry * A,SectionEntry * B)245 static int64_t computeDelta(SectionEntry *A, SectionEntry *B) {
246 int64_t ObjDistance =
247 static_cast<int64_t>(A->ObjAddress) - static_cast<int64_t>(B->ObjAddress);
248 int64_t MemDistance = A->LoadAddress - B->LoadAddress;
249 return ObjDistance - MemDistance;
250 }
251
252 template <typename Impl>
registerEHFrames()253 void RuntimeDyldMachOCRTPBase<Impl>::registerEHFrames() {
254
255 if (!MemMgr)
256 return;
257 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
258 EHFrameRelatedSections &SectionInfo = UnregisteredEHFrameSections[i];
259 if (SectionInfo.EHFrameSID == RTDYLD_INVALID_SECTION_ID ||
260 SectionInfo.TextSID == RTDYLD_INVALID_SECTION_ID)
261 continue;
262 SectionEntry *Text = &Sections[SectionInfo.TextSID];
263 SectionEntry *EHFrame = &Sections[SectionInfo.EHFrameSID];
264 SectionEntry *ExceptTab = nullptr;
265 if (SectionInfo.ExceptTabSID != RTDYLD_INVALID_SECTION_ID)
266 ExceptTab = &Sections[SectionInfo.ExceptTabSID];
267
268 int64_t DeltaForText = computeDelta(Text, EHFrame);
269 int64_t DeltaForEH = 0;
270 if (ExceptTab)
271 DeltaForEH = computeDelta(ExceptTab, EHFrame);
272
273 unsigned char *P = EHFrame->Address;
274 unsigned char *End = P + EHFrame->Size;
275 do {
276 P = processFDE(P, DeltaForText, DeltaForEH);
277 } while (P != End);
278
279 MemMgr->registerEHFrames(EHFrame->Address, EHFrame->LoadAddress,
280 EHFrame->Size);
281 }
282 UnregisteredEHFrameSections.clear();
283 }
284
285 std::unique_ptr<RuntimeDyldMachO>
create(Triple::ArchType Arch,RTDyldMemoryManager * MM)286 RuntimeDyldMachO::create(Triple::ArchType Arch, RTDyldMemoryManager *MM) {
287 switch (Arch) {
288 default:
289 llvm_unreachable("Unsupported target for RuntimeDyldMachO.");
290 break;
291 case Triple::arm: return make_unique<RuntimeDyldMachOARM>(MM);
292 case Triple::aarch64: return make_unique<RuntimeDyldMachOAArch64>(MM);
293 case Triple::x86: return make_unique<RuntimeDyldMachOI386>(MM);
294 case Triple::x86_64: return make_unique<RuntimeDyldMachOX86_64>(MM);
295 }
296 }
297
298 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
loadObject(const object::ObjectFile & O)299 RuntimeDyldMachO::loadObject(const object::ObjectFile &O) {
300 unsigned SectionStartIdx, SectionEndIdx;
301 std::tie(SectionStartIdx, SectionEndIdx) = loadObjectImpl(O);
302 return llvm::make_unique<LoadedMachOObjectInfo>(*this, SectionStartIdx,
303 SectionEndIdx);
304 }
305
306 } // end namespace llvm
307