1 //===-- RuntimeDyldELF.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 ELF support for the MC-JIT runtime dynamic linker.
12 //===----------------------------------------------------------------------===//
14 #include "RuntimeDyldELF.h"
15 #include "RuntimeDyldCheckerImpl.h"
16 #include "Targets/RuntimeDyldELFMips.h"
17 #include "llvm/ADT/IntervalMap.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/MC/MCStreamer.h"
22 #include "llvm/Object/ELFObjectFile.h"
23 #include "llvm/Object/ObjectFile.h"
24 #include "llvm/Support/ELF.h"
25 #include "llvm/Support/Endian.h"
26 #include "llvm/Support/MemoryBuffer.h"
27 #include "llvm/Support/TargetRegistry.h"
30 using namespace llvm::object;
31 using namespace llvm::support::endian;
33 #define DEBUG_TYPE "dyld"
35 static void or32le(void *P, int32_t V) { write32le(P, read32le(P) | V); }
37 static void or32AArch64Imm(void *L, uint64_t Imm) {
38 or32le(L, (Imm & 0xFFF) << 10);
41 template <class T> static void write(bool isBE, void *P, T V) {
42 isBE ? write<T, support::big>(P, V) : write<T, support::little>(P, V);
45 static void write32AArch64Addr(void *L, uint64_t Imm) {
46 uint32_t ImmLo = (Imm & 0x3) << 29;
47 uint32_t ImmHi = (Imm & 0x1FFFFC) << 3;
48 uint64_t Mask = (0x3 << 29) | (0x1FFFFC << 3);
49 write32le(L, (read32le(L) & ~Mask) | ImmLo | ImmHi);
52 // Return the bits [Start, End] from Val shifted Start bits.
53 // For instance, getBits(0xF0, 4, 8) returns 0xF.
54 static uint64_t getBits(uint64_t Val, int Start, int End) {
55 uint64_t Mask = ((uint64_t)1 << (End + 1 - Start)) - 1;
56 return (Val >> Start) & Mask;
61 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> {
62 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
64 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
65 typedef Elf_Sym_Impl<ELFT> Elf_Sym;
66 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
67 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
69 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
71 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type;
74 DyldELFObject(MemoryBufferRef Wrapper, std::error_code &ec);
76 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
78 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr);
80 // Methods for type inquiry through isa, cast and dyn_cast
81 static inline bool classof(const Binary *v) {
82 return (isa<ELFObjectFile<ELFT>>(v) &&
83 classof(cast<ELFObjectFile<ELFT>>(v)));
85 static inline bool classof(const ELFObjectFile<ELFT> *v) {
86 return v->isDyldType();
92 // The MemoryBuffer passed into this constructor is just a wrapper around the
93 // actual memory. Ultimately, the Binary parent class will take ownership of
94 // this MemoryBuffer object but not the underlying memory.
96 DyldELFObject<ELFT>::DyldELFObject(MemoryBufferRef Wrapper, std::error_code &EC)
97 : ELFObjectFile<ELFT>(Wrapper, EC) {
98 this->isDyldELFObject = true;
101 template <class ELFT>
102 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
104 DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
106 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
108 // This assumes the address passed in matches the target address bitness
109 // The template-based type cast handles everything else.
110 shdr->sh_addr = static_cast<addr_type>(Addr);
113 template <class ELFT>
114 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
117 Elf_Sym *sym = const_cast<Elf_Sym *>(
118 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl()));
120 // This assumes the address passed in matches the target address bitness
121 // The template-based type cast handles everything else.
122 sym->st_value = static_cast<addr_type>(Addr);
125 class LoadedELFObjectInfo final
126 : public RuntimeDyld::LoadedObjectInfoHelper<LoadedELFObjectInfo> {
128 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
129 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
131 OwningBinary<ObjectFile>
132 getObjectForDebug(const ObjectFile &Obj) const override;
135 template <typename ELFT>
136 std::unique_ptr<DyldELFObject<ELFT>>
137 createRTDyldELFObject(MemoryBufferRef Buffer,
138 const ObjectFile &SourceObject,
139 const LoadedELFObjectInfo &L,
140 std::error_code &ec) {
141 typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
142 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type;
144 std::unique_ptr<DyldELFObject<ELFT>> Obj =
145 llvm::make_unique<DyldELFObject<ELFT>>(Buffer, ec);
147 // Iterate over all sections in the object.
148 auto SI = SourceObject.section_begin();
149 for (const auto &Sec : Obj->sections()) {
150 StringRef SectionName;
151 Sec.getName(SectionName);
152 if (SectionName != "") {
153 DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
154 Elf_Shdr *shdr = const_cast<Elf_Shdr *>(
155 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
157 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) {
158 // This assumes that the address passed in matches the target address
159 // bitness. The template-based type cast handles everything else.
160 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr);
169 OwningBinary<ObjectFile> createELFDebugObject(const ObjectFile &Obj,
170 const LoadedELFObjectInfo &L) {
171 assert(Obj.isELF() && "Not an ELF object file.");
173 std::unique_ptr<MemoryBuffer> Buffer =
174 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName());
178 std::unique_ptr<ObjectFile> DebugObj;
179 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) {
180 typedef ELFType<support::little, false> ELF32LE;
181 DebugObj = createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L,
183 } else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) {
184 typedef ELFType<support::big, false> ELF32BE;
185 DebugObj = createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L,
187 } else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) {
188 typedef ELFType<support::big, true> ELF64BE;
189 DebugObj = createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L,
191 } else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) {
192 typedef ELFType<support::little, true> ELF64LE;
193 DebugObj = createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L,
196 llvm_unreachable("Unexpected ELF format");
198 assert(!ec && "Could not construct copy ELF object file");
200 return OwningBinary<ObjectFile>(std::move(DebugObj), std::move(Buffer));
203 OwningBinary<ObjectFile>
204 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const {
205 return createELFDebugObject(Obj, *this);
208 } // anonymous namespace
212 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr,
213 JITSymbolResolver &Resolver)
214 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {}
215 RuntimeDyldELF::~RuntimeDyldELF() {}
217 void RuntimeDyldELF::registerEHFrames() {
218 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
219 SID EHFrameSID = UnregisteredEHFrameSections[i];
220 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
221 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
222 size_t EHFrameSize = Sections[EHFrameSID].getSize();
223 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
224 RegisteredEHFrameSections.push_back(EHFrameSID);
226 UnregisteredEHFrameSections.clear();
229 void RuntimeDyldELF::deregisterEHFrames() {
230 for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) {
231 SID EHFrameSID = RegisteredEHFrameSections[i];
232 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
233 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
234 size_t EHFrameSize = Sections[EHFrameSID].getSize();
235 MemMgr.deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
237 RegisteredEHFrameSections.clear();
240 std::unique_ptr<RuntimeDyldELF>
241 llvm::RuntimeDyldELF::create(Triple::ArchType Arch,
242 RuntimeDyld::MemoryManager &MemMgr,
243 JITSymbolResolver &Resolver) {
246 return make_unique<RuntimeDyldELF>(MemMgr, Resolver);
250 case Triple::mips64el:
251 return make_unique<RuntimeDyldELFMips>(MemMgr, Resolver);
255 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
256 RuntimeDyldELF::loadObject(const object::ObjectFile &O) {
257 if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
258 return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr);
261 raw_string_ostream ErrStream(ErrorStr);
262 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, "");
267 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
268 uint64_t Offset, uint64_t Value,
269 uint32_t Type, int64_t Addend,
270 uint64_t SymOffset) {
273 llvm_unreachable("Relocation type not implemented yet!");
275 case ELF::R_X86_64_64: {
276 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) =
278 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
279 << format("%p\n", Section.getAddressWithOffset(Offset)));
282 case ELF::R_X86_64_32:
283 case ELF::R_X86_64_32S: {
285 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
286 (Type == ELF::R_X86_64_32S &&
287 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
288 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
289 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
291 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at "
292 << format("%p\n", Section.getAddressWithOffset(Offset)));
295 case ELF::R_X86_64_PC8: {
296 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
297 int64_t RealOffset = Value + Addend - FinalAddress;
298 assert(isInt<8>(RealOffset));
299 int8_t TruncOffset = (RealOffset & 0xFF);
300 Section.getAddress()[Offset] = TruncOffset;
303 case ELF::R_X86_64_PC32: {
304 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
305 int64_t RealOffset = Value + Addend - FinalAddress;
306 assert(isInt<32>(RealOffset));
307 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
308 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
312 case ELF::R_X86_64_PC64: {
313 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
314 int64_t RealOffset = Value + Addend - FinalAddress;
315 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) =
322 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
323 uint64_t Offset, uint32_t Value,
324 uint32_t Type, int32_t Addend) {
326 case ELF::R_386_32: {
327 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
331 case ELF::R_386_PC32: {
332 uint32_t FinalAddress =
333 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
334 uint32_t RealOffset = Value + Addend - FinalAddress;
335 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
340 // There are other relocation types, but it appears these are the
341 // only ones currently used by the LLVM ELF object writer
342 llvm_unreachable("Relocation type not implemented yet!");
347 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
348 uint64_t Offset, uint64_t Value,
349 uint32_t Type, int64_t Addend) {
350 uint32_t *TargetPtr =
351 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
352 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
353 // Data should use target endian. Code should always use little endian.
354 bool isBE = Arch == Triple::aarch64_be;
356 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
357 << format("%llx", Section.getAddressWithOffset(Offset))
358 << " FinalAddress: 0x" << format("%llx", FinalAddress)
359 << " Value: 0x" << format("%llx", Value) << " Type: 0x"
360 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend)
365 llvm_unreachable("Relocation type not implemented yet!");
367 case ELF::R_AARCH64_ABS64:
368 write(isBE, TargetPtr, Value + Addend);
370 case ELF::R_AARCH64_PREL32: {
371 uint64_t Result = Value + Addend - FinalAddress;
372 assert(static_cast<int64_t>(Result) >= INT32_MIN &&
373 static_cast<int64_t>(Result) <= UINT32_MAX);
374 write(isBE, TargetPtr, static_cast<uint32_t>(Result & 0xffffffffU));
377 case ELF::R_AARCH64_PREL64:
378 write(isBE, TargetPtr, Value + Addend - FinalAddress);
380 case ELF::R_AARCH64_CALL26: // fallthrough
381 case ELF::R_AARCH64_JUMP26: {
382 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
384 uint64_t BranchImm = Value + Addend - FinalAddress;
386 // "Check that -2^27 <= result < 2^27".
387 assert(isInt<28>(BranchImm));
388 or32le(TargetPtr, (BranchImm & 0x0FFFFFFC) >> 2);
391 case ELF::R_AARCH64_MOVW_UABS_G3:
392 or32le(TargetPtr, ((Value + Addend) & 0xFFFF000000000000) >> 43);
394 case ELF::R_AARCH64_MOVW_UABS_G2_NC:
395 or32le(TargetPtr, ((Value + Addend) & 0xFFFF00000000) >> 27);
397 case ELF::R_AARCH64_MOVW_UABS_G1_NC:
398 or32le(TargetPtr, ((Value + Addend) & 0xFFFF0000) >> 11);
400 case ELF::R_AARCH64_MOVW_UABS_G0_NC:
401 or32le(TargetPtr, ((Value + Addend) & 0xFFFF) << 5);
403 case ELF::R_AARCH64_ADR_PREL_PG_HI21: {
404 // Operation: Page(S+A) - Page(P)
406 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL);
408 // Check that -2^32 <= X < 2^32
409 assert(isInt<33>(Result) && "overflow check failed for relocation");
411 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken
412 // from bits 32:12 of X.
413 write32AArch64Addr(TargetPtr, Result >> 12);
416 case ELF::R_AARCH64_ADD_ABS_LO12_NC:
418 // Immediate goes in bits 21:10 of LD/ST instruction, taken
419 // from bits 11:0 of X
420 or32AArch64Imm(TargetPtr, Value + Addend);
422 case ELF::R_AARCH64_LDST32_ABS_LO12_NC:
424 // Immediate goes in bits 21:10 of LD/ST instruction, taken
425 // from bits 11:2 of X
426 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 2, 11));
428 case ELF::R_AARCH64_LDST64_ABS_LO12_NC:
430 // Immediate goes in bits 21:10 of LD/ST instruction, taken
431 // from bits 11:3 of X
432 or32AArch64Imm(TargetPtr, getBits(Value + Addend, 3, 11));
437 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
438 uint64_t Offset, uint32_t Value,
439 uint32_t Type, int32_t Addend) {
440 // TODO: Add Thumb relocations.
441 uint32_t *TargetPtr =
442 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
443 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
446 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
447 << Section.getAddressWithOffset(Offset)
448 << " FinalAddress: " << format("%p", FinalAddress) << " Value: "
449 << format("%x", Value) << " Type: " << format("%x", Type)
450 << " Addend: " << format("%x", Addend) << "\n");
454 llvm_unreachable("Not implemented relocation type!");
456 case ELF::R_ARM_NONE:
458 // Write a 31bit signed offset
459 case ELF::R_ARM_PREL31:
460 support::ulittle32_t::ref{TargetPtr} =
461 (support::ulittle32_t::ref{TargetPtr} & 0x80000000) |
462 ((Value - FinalAddress) & ~0x80000000);
464 case ELF::R_ARM_TARGET1:
465 case ELF::R_ARM_ABS32:
466 support::ulittle32_t::ref{TargetPtr} = Value;
468 // Write first 16 bit of 32 bit value to the mov instruction.
469 // Last 4 bit should be shifted.
470 case ELF::R_ARM_MOVW_ABS_NC:
471 case ELF::R_ARM_MOVT_ABS:
472 if (Type == ELF::R_ARM_MOVW_ABS_NC)
473 Value = Value & 0xFFFF;
474 else if (Type == ELF::R_ARM_MOVT_ABS)
475 Value = (Value >> 16) & 0xFFFF;
476 support::ulittle32_t::ref{TargetPtr} =
477 (support::ulittle32_t::ref{TargetPtr} & ~0x000F0FFF) | (Value & 0xFFF) |
478 (((Value >> 12) & 0xF) << 16);
480 // Write 24 bit relative value to the branch instruction.
481 case ELF::R_ARM_PC24: // Fall through.
482 case ELF::R_ARM_CALL: // Fall through.
483 case ELF::R_ARM_JUMP24:
484 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
485 RelValue = (RelValue & 0x03FFFFFC) >> 2;
486 assert((support::ulittle32_t::ref{TargetPtr} & 0xFFFFFF) == 0xFFFFFE);
487 support::ulittle32_t::ref{TargetPtr} =
488 (support::ulittle32_t::ref{TargetPtr} & 0xFF000000) | RelValue;
493 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) {
494 if (Arch == Triple::UnknownArch ||
495 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) {
496 IsMipsO32ABI = false;
497 IsMipsN32ABI = false;
498 IsMipsN64ABI = false;
502 Obj.getPlatformFlags(AbiVariant);
503 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32;
504 IsMipsN32ABI = AbiVariant & ELF::EF_MIPS_ABI2;
505 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips");
508 // Return the .TOC. section and offset.
509 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj,
510 ObjSectionToIDMap &LocalSections,
511 RelocationValueRef &Rel) {
512 // Set a default SectionID in case we do not find a TOC section below.
513 // This may happen for references to TOC base base (sym@toc, .odp
514 // relocation) without a .toc directive. In this case just use the
515 // first section (which is usually the .odp) since the code won't
516 // reference the .toc base directly.
517 Rel.SymbolName = nullptr;
520 // The TOC consists of sections .got, .toc, .tocbss, .plt in that
521 // order. The TOC starts where the first of these sections starts.
522 for (auto &Section: Obj.sections()) {
523 StringRef SectionName;
524 if (auto EC = Section.getName(SectionName))
525 return errorCodeToError(EC);
527 if (SectionName == ".got"
528 || SectionName == ".toc"
529 || SectionName == ".tocbss"
530 || SectionName == ".plt") {
531 if (auto SectionIDOrErr =
532 findOrEmitSection(Obj, Section, false, LocalSections))
533 Rel.SectionID = *SectionIDOrErr;
535 return SectionIDOrErr.takeError();
540 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
541 // thus permitting a full 64 Kbytes segment.
544 return Error::success();
547 // Returns the sections and offset associated with the ODP entry referenced
549 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
550 ObjSectionToIDMap &LocalSections,
551 RelocationValueRef &Rel) {
552 // Get the ELF symbol value (st_value) to compare with Relocation offset in
554 for (section_iterator si = Obj.section_begin(), se = Obj.section_end();
556 section_iterator RelSecI = si->getRelocatedSection();
557 if (RelSecI == Obj.section_end())
560 StringRef RelSectionName;
561 if (auto EC = RelSecI->getName(RelSectionName))
562 return errorCodeToError(EC);
564 if (RelSectionName != ".opd")
567 for (elf_relocation_iterator i = si->relocation_begin(),
568 e = si->relocation_end();
570 // The R_PPC64_ADDR64 relocation indicates the first field
572 uint64_t TypeFunc = i->getType();
573 if (TypeFunc != ELF::R_PPC64_ADDR64) {
578 uint64_t TargetSymbolOffset = i->getOffset();
579 symbol_iterator TargetSymbol = i->getSymbol();
581 if (auto AddendOrErr = i->getAddend())
582 Addend = *AddendOrErr;
584 return errorCodeToError(AddendOrErr.getError());
590 // Just check if following relocation is a R_PPC64_TOC
591 uint64_t TypeTOC = i->getType();
592 if (TypeTOC != ELF::R_PPC64_TOC)
595 // Finally compares the Symbol value and the target symbol offset
596 // to check if this .opd entry refers to the symbol the relocation
598 if (Rel.Addend != (int64_t)TargetSymbolOffset)
601 section_iterator TSI = Obj.section_end();
602 if (auto TSIOrErr = TargetSymbol->getSection())
605 return TSIOrErr.takeError();
606 assert(TSI != Obj.section_end() && "TSI should refer to a valid section");
608 bool IsCode = TSI->isText();
609 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode,
611 Rel.SectionID = *SectionIDOrErr;
613 return SectionIDOrErr.takeError();
614 Rel.Addend = (intptr_t)Addend;
615 return Error::success();
618 llvm_unreachable("Attempting to get address of ODP entry!");
621 // Relocation masks following the #lo(value), #hi(value), #ha(value),
622 // #higher(value), #highera(value), #highest(value), and #highesta(value)
623 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi
626 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; }
628 static inline uint16_t applyPPChi(uint64_t value) {
629 return (value >> 16) & 0xffff;
632 static inline uint16_t applyPPCha (uint64_t value) {
633 return ((value + 0x8000) >> 16) & 0xffff;
636 static inline uint16_t applyPPChigher(uint64_t value) {
637 return (value >> 32) & 0xffff;
640 static inline uint16_t applyPPChighera (uint64_t value) {
641 return ((value + 0x8000) >> 32) & 0xffff;
644 static inline uint16_t applyPPChighest(uint64_t value) {
645 return (value >> 48) & 0xffff;
648 static inline uint16_t applyPPChighesta (uint64_t value) {
649 return ((value + 0x8000) >> 48) & 0xffff;
652 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section,
653 uint64_t Offset, uint64_t Value,
654 uint32_t Type, int64_t Addend) {
655 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
658 llvm_unreachable("Relocation type not implemented yet!");
660 case ELF::R_PPC_ADDR16_LO:
661 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
663 case ELF::R_PPC_ADDR16_HI:
664 writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
666 case ELF::R_PPC_ADDR16_HA:
667 writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
672 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
673 uint64_t Offset, uint64_t Value,
674 uint32_t Type, int64_t Addend) {
675 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
678 llvm_unreachable("Relocation type not implemented yet!");
680 case ELF::R_PPC64_ADDR16:
681 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
683 case ELF::R_PPC64_ADDR16_DS:
684 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
686 case ELF::R_PPC64_ADDR16_LO:
687 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
689 case ELF::R_PPC64_ADDR16_LO_DS:
690 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
692 case ELF::R_PPC64_ADDR16_HI:
693 writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
695 case ELF::R_PPC64_ADDR16_HA:
696 writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
698 case ELF::R_PPC64_ADDR16_HIGHER:
699 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend));
701 case ELF::R_PPC64_ADDR16_HIGHERA:
702 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend));
704 case ELF::R_PPC64_ADDR16_HIGHEST:
705 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend));
707 case ELF::R_PPC64_ADDR16_HIGHESTA:
708 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend));
710 case ELF::R_PPC64_ADDR14: {
711 assert(((Value + Addend) & 3) == 0);
712 // Preserve the AA/LK bits in the branch instruction
713 uint8_t aalk = *(LocalAddress + 3);
714 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
716 case ELF::R_PPC64_REL16_LO: {
717 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
718 uint64_t Delta = Value - FinalAddress + Addend;
719 writeInt16BE(LocalAddress, applyPPClo(Delta));
721 case ELF::R_PPC64_REL16_HI: {
722 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
723 uint64_t Delta = Value - FinalAddress + Addend;
724 writeInt16BE(LocalAddress, applyPPChi(Delta));
726 case ELF::R_PPC64_REL16_HA: {
727 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
728 uint64_t Delta = Value - FinalAddress + Addend;
729 writeInt16BE(LocalAddress, applyPPCha(Delta));
731 case ELF::R_PPC64_ADDR32: {
732 int32_t Result = static_cast<int32_t>(Value + Addend);
733 if (SignExtend32<32>(Result) != Result)
734 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
735 writeInt32BE(LocalAddress, Result);
737 case ELF::R_PPC64_REL24: {
738 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
739 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
740 if (SignExtend32<26>(delta) != delta)
741 llvm_unreachable("Relocation R_PPC64_REL24 overflow");
742 // Generates a 'bl <address>' instruction
743 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
745 case ELF::R_PPC64_REL32: {
746 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
747 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
748 if (SignExtend32<32>(delta) != delta)
749 llvm_unreachable("Relocation R_PPC64_REL32 overflow");
750 writeInt32BE(LocalAddress, delta);
752 case ELF::R_PPC64_REL64: {
753 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
754 uint64_t Delta = Value - FinalAddress + Addend;
755 writeInt64BE(LocalAddress, Delta);
757 case ELF::R_PPC64_ADDR64:
758 writeInt64BE(LocalAddress, Value + Addend);
763 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
764 uint64_t Offset, uint64_t Value,
765 uint32_t Type, int64_t Addend) {
766 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
769 llvm_unreachable("Relocation type not implemented yet!");
771 case ELF::R_390_PC16DBL:
772 case ELF::R_390_PLT16DBL: {
773 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
774 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
775 writeInt16BE(LocalAddress, Delta / 2);
778 case ELF::R_390_PC32DBL:
779 case ELF::R_390_PLT32DBL: {
780 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
781 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
782 writeInt32BE(LocalAddress, Delta / 2);
785 case ELF::R_390_PC32: {
786 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
787 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
788 writeInt32BE(LocalAddress, Delta);
792 writeInt64BE(LocalAddress, Value + Addend);
794 case ELF::R_390_PC64: {
795 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
796 writeInt64BE(LocalAddress, Delta);
802 // The target location for the relocation is described by RE.SectionID and
803 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
804 // SectionEntry has three members describing its location.
805 // SectionEntry::Address is the address at which the section has been loaded
806 // into memory in the current (host) process. SectionEntry::LoadAddress is the
807 // address that the section will have in the target process.
808 // SectionEntry::ObjAddress is the address of the bits for this section in the
809 // original emitted object image (also in the current address space).
811 // Relocations will be applied as if the section were loaded at
812 // SectionEntry::LoadAddress, but they will be applied at an address based
813 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to
814 // Target memory contents if they are required for value calculations.
816 // The Value parameter here is the load address of the symbol for the
817 // relocation to be applied. For relocations which refer to symbols in the
818 // current object Value will be the LoadAddress of the section in which
819 // the symbol resides (RE.Addend provides additional information about the
820 // symbol location). For external symbols, Value will be the address of the
821 // symbol in the target address space.
822 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
824 const SectionEntry &Section = Sections[RE.SectionID];
825 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
826 RE.SymOffset, RE.SectionID);
829 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
830 uint64_t Offset, uint64_t Value,
831 uint32_t Type, int64_t Addend,
832 uint64_t SymOffset, SID SectionID) {
835 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
838 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
839 (uint32_t)(Addend & 0xffffffffL));
841 case Triple::aarch64:
842 case Triple::aarch64_be:
843 resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
845 case Triple::arm: // Fall through.
848 case Triple::thumbeb:
849 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
850 (uint32_t)(Addend & 0xffffffffL));
853 resolvePPC32Relocation(Section, Offset, Value, Type, Addend);
855 case Triple::ppc64: // Fall through.
856 case Triple::ppc64le:
857 resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
859 case Triple::systemz:
860 resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
863 llvm_unreachable("Unsupported CPU type!");
867 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const {
868 return (void *)(Sections[SectionID].getObjAddress() + Offset);
871 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) {
872 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
873 if (Value.SymbolName)
874 addRelocationForSymbol(RE, Value.SymbolName);
876 addRelocationForSection(RE, Value.SectionID);
879 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType,
880 bool IsLocal) const {
882 case ELF::R_MICROMIPS_GOT16:
884 return ELF::R_MICROMIPS_LO16;
886 case ELF::R_MICROMIPS_HI16:
887 return ELF::R_MICROMIPS_LO16;
888 case ELF::R_MIPS_GOT16:
890 return ELF::R_MIPS_LO16;
892 case ELF::R_MIPS_HI16:
893 return ELF::R_MIPS_LO16;
894 case ELF::R_MIPS_PCHI16:
895 return ELF::R_MIPS_PCLO16;
899 return ELF::R_MIPS_NONE;
902 // Sometimes we don't need to create thunk for a branch.
903 // This typically happens when branch target is located
904 // in the same object file. In such case target is either
905 // a weak symbol or symbol in a different executable section.
906 // This function checks if branch target is located in the
907 // same object file and if distance between source and target
908 // fits R_AARCH64_CALL26 relocation. If both conditions are
909 // met, it emits direct jump to the target and returns true.
910 // Otherwise false is returned and thunk is created.
911 bool RuntimeDyldELF::resolveAArch64ShortBranch(
912 unsigned SectionID, relocation_iterator RelI,
913 const RelocationValueRef &Value) {
915 if (Value.SymbolName) {
916 auto Loc = GlobalSymbolTable.find(Value.SymbolName);
918 // Don't create direct branch for external symbols.
919 if (Loc == GlobalSymbolTable.end())
922 const auto &SymInfo = Loc->second;
924 uint64_t(Sections[SymInfo.getSectionID()].getLoadAddressWithOffset(
925 SymInfo.getOffset()));
927 Address = uint64_t(Sections[Value.SectionID].getLoadAddress());
929 uint64_t Offset = RelI->getOffset();
930 uint64_t SourceAddress = Sections[SectionID].getLoadAddressWithOffset(Offset);
932 // R_AARCH64_CALL26 requires immediate to be in range -2^27 <= imm < 2^27
933 // If distance between source and target is out of range then we should
935 if (!isInt<28>(Address + Value.Addend - SourceAddress))
938 resolveRelocation(Sections[SectionID], Offset, Address, RelI->getType(),
944 Expected<relocation_iterator>
945 RuntimeDyldELF::processRelocationRef(
946 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O,
947 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) {
948 const auto &Obj = cast<ELFObjectFileBase>(O);
949 uint64_t RelType = RelI->getType();
950 ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend();
951 int64_t Addend = AddendOrErr ? *AddendOrErr : 0;
952 elf_symbol_iterator Symbol = RelI->getSymbol();
954 // Obtain the symbol name which is referenced in the relocation
955 StringRef TargetName;
956 if (Symbol != Obj.symbol_end()) {
957 if (auto TargetNameOrErr = Symbol->getName())
958 TargetName = *TargetNameOrErr;
960 return TargetNameOrErr.takeError();
962 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend
963 << " TargetName: " << TargetName << "\n");
964 RelocationValueRef Value;
965 // First search for the symbol in the local symbol table
966 SymbolRef::Type SymType = SymbolRef::ST_Unknown;
968 // Search for the symbol in the global symbol table
969 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end();
970 if (Symbol != Obj.symbol_end()) {
971 gsi = GlobalSymbolTable.find(TargetName.data());
972 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType();
975 raw_string_ostream OS(Buf);
976 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, "");
978 report_fatal_error(Buf);
980 SymType = *SymTypeOrErr;
982 if (gsi != GlobalSymbolTable.end()) {
983 const auto &SymInfo = gsi->second;
984 Value.SectionID = SymInfo.getSectionID();
985 Value.Offset = SymInfo.getOffset();
986 Value.Addend = SymInfo.getOffset() + Addend;
989 case SymbolRef::ST_Debug: {
990 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
991 // and can be changed by another developers. Maybe best way is add
992 // a new symbol type ST_Section to SymbolRef and use it.
993 auto SectionOrErr = Symbol->getSection();
996 raw_string_ostream OS(Buf);
997 logAllUnhandledErrors(SectionOrErr.takeError(), OS, "");
999 report_fatal_error(Buf);
1001 section_iterator si = *SectionOrErr;
1002 if (si == Obj.section_end())
1003 llvm_unreachable("Symbol section not found, bad object file format!");
1004 DEBUG(dbgs() << "\t\tThis is section symbol\n");
1005 bool isCode = si->isText();
1006 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode,
1008 Value.SectionID = *SectionIDOrErr;
1010 return SectionIDOrErr.takeError();
1011 Value.Addend = Addend;
1014 case SymbolRef::ST_Data:
1015 case SymbolRef::ST_Function:
1016 case SymbolRef::ST_Unknown: {
1017 Value.SymbolName = TargetName.data();
1018 Value.Addend = Addend;
1020 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
1021 // will manifest here as a NULL symbol name.
1022 // We can set this as a valid (but empty) symbol name, and rely
1023 // on addRelocationForSymbol to handle this.
1024 if (!Value.SymbolName)
1025 Value.SymbolName = "";
1029 llvm_unreachable("Unresolved symbol type!");
1034 uint64_t Offset = RelI->getOffset();
1036 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset
1038 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be) &&
1039 (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26)) {
1040 // This is an AArch64 branch relocation, need to use a stub function.
1041 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
1042 SectionEntry &Section = Sections[SectionID];
1044 // Look for an existing stub.
1045 StubMap::const_iterator i = Stubs.find(Value);
1046 if (i != Stubs.end()) {
1047 resolveRelocation(Section, Offset,
1048 (uint64_t)Section.getAddressWithOffset(i->second),
1050 DEBUG(dbgs() << " Stub function found\n");
1051 } else if (!resolveAArch64ShortBranch(SectionID, RelI, Value)) {
1052 // Create a new stub function.
1053 DEBUG(dbgs() << " Create a new stub function\n");
1054 Stubs[Value] = Section.getStubOffset();
1055 uint8_t *StubTargetAddr = createStubFunction(
1056 Section.getAddressWithOffset(Section.getStubOffset()));
1058 RelocationEntry REmovz_g3(SectionID,
1059 StubTargetAddr - Section.getAddress(),
1060 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
1061 RelocationEntry REmovk_g2(SectionID, StubTargetAddr -
1062 Section.getAddress() + 4,
1063 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
1064 RelocationEntry REmovk_g1(SectionID, StubTargetAddr -
1065 Section.getAddress() + 8,
1066 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
1067 RelocationEntry REmovk_g0(SectionID, StubTargetAddr -
1068 Section.getAddress() + 12,
1069 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
1071 if (Value.SymbolName) {
1072 addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1073 addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1074 addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1075 addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1077 addRelocationForSection(REmovz_g3, Value.SectionID);
1078 addRelocationForSection(REmovk_g2, Value.SectionID);
1079 addRelocationForSection(REmovk_g1, Value.SectionID);
1080 addRelocationForSection(REmovk_g0, Value.SectionID);
1082 resolveRelocation(Section, Offset,
1083 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(
1084 Section.getStubOffset())),
1086 Section.advanceStubOffset(getMaxStubSize());
1088 } else if (Arch == Triple::arm) {
1089 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL ||
1090 RelType == ELF::R_ARM_JUMP24) {
1091 // This is an ARM branch relocation, need to use a stub function.
1092 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n");
1093 SectionEntry &Section = Sections[SectionID];
1095 // Look for an existing stub.
1096 StubMap::const_iterator i = Stubs.find(Value);
1097 if (i != Stubs.end()) {
1100 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)),
1102 DEBUG(dbgs() << " Stub function found\n");
1104 // Create a new stub function.
1105 DEBUG(dbgs() << " Create a new stub function\n");
1106 Stubs[Value] = Section.getStubOffset();
1107 uint8_t *StubTargetAddr = createStubFunction(
1108 Section.getAddressWithOffset(Section.getStubOffset()));
1109 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1110 ELF::R_ARM_ABS32, Value.Addend);
1111 if (Value.SymbolName)
1112 addRelocationForSymbol(RE, Value.SymbolName);
1114 addRelocationForSection(RE, Value.SectionID);
1116 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1117 Section.getAddressWithOffset(
1118 Section.getStubOffset())),
1120 Section.advanceStubOffset(getMaxStubSize());
1123 uint32_t *Placeholder =
1124 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset));
1125 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 ||
1126 RelType == ELF::R_ARM_ABS32) {
1127 Value.Addend += *Placeholder;
1128 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) {
1129 // See ELF for ARM documentation
1130 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12));
1132 processSimpleRelocation(SectionID, Offset, RelType, Value);
1134 } else if (IsMipsO32ABI) {
1135 uint8_t *Placeholder = reinterpret_cast<uint8_t *>(
1136 computePlaceholderAddress(SectionID, Offset));
1137 uint32_t Opcode = readBytesUnaligned(Placeholder, 4);
1138 if (RelType == ELF::R_MIPS_26) {
1139 // This is an Mips branch relocation, need to use a stub function.
1140 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1141 SectionEntry &Section = Sections[SectionID];
1143 // Extract the addend from the instruction.
1144 // We shift up by two since the Value will be down shifted again
1145 // when applying the relocation.
1146 uint32_t Addend = (Opcode & 0x03ffffff) << 2;
1148 Value.Addend += Addend;
1150 // Look up for existing stub.
1151 StubMap::const_iterator i = Stubs.find(Value);
1152 if (i != Stubs.end()) {
1153 RelocationEntry RE(SectionID, Offset, RelType, i->second);
1154 addRelocationForSection(RE, SectionID);
1155 DEBUG(dbgs() << " Stub function found\n");
1157 // Create a new stub function.
1158 DEBUG(dbgs() << " Create a new stub function\n");
1159 Stubs[Value] = Section.getStubOffset();
1161 unsigned AbiVariant;
1162 O.getPlatformFlags(AbiVariant);
1164 uint8_t *StubTargetAddr = createStubFunction(
1165 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1167 // Creating Hi and Lo relocations for the filled stub instructions.
1168 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1169 ELF::R_MIPS_HI16, Value.Addend);
1170 RelocationEntry RELo(SectionID,
1171 StubTargetAddr - Section.getAddress() + 4,
1172 ELF::R_MIPS_LO16, Value.Addend);
1174 if (Value.SymbolName) {
1175 addRelocationForSymbol(REHi, Value.SymbolName);
1176 addRelocationForSymbol(RELo, Value.SymbolName);
1179 addRelocationForSection(REHi, Value.SectionID);
1180 addRelocationForSection(RELo, Value.SectionID);
1183 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1184 addRelocationForSection(RE, SectionID);
1185 Section.advanceStubOffset(getMaxStubSize());
1187 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) {
1188 int64_t Addend = (Opcode & 0x0000ffff) << 16;
1189 RelocationEntry RE(SectionID, Offset, RelType, Addend);
1190 PendingRelocs.push_back(std::make_pair(Value, RE));
1191 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) {
1192 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff);
1193 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) {
1194 const RelocationValueRef &MatchingValue = I->first;
1195 RelocationEntry &Reloc = I->second;
1196 if (MatchingValue == Value &&
1197 RelType == getMatchingLoRelocation(Reloc.RelType) &&
1198 SectionID == Reloc.SectionID) {
1199 Reloc.Addend += Addend;
1200 if (Value.SymbolName)
1201 addRelocationForSymbol(Reloc, Value.SymbolName);
1203 addRelocationForSection(Reloc, Value.SectionID);
1204 I = PendingRelocs.erase(I);
1208 RelocationEntry RE(SectionID, Offset, RelType, Addend);
1209 if (Value.SymbolName)
1210 addRelocationForSymbol(RE, Value.SymbolName);
1212 addRelocationForSection(RE, Value.SectionID);
1214 if (RelType == ELF::R_MIPS_32)
1215 Value.Addend += Opcode;
1216 else if (RelType == ELF::R_MIPS_PC16)
1217 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2);
1218 else if (RelType == ELF::R_MIPS_PC19_S2)
1219 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2);
1220 else if (RelType == ELF::R_MIPS_PC21_S2)
1221 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2);
1222 else if (RelType == ELF::R_MIPS_PC26_S2)
1223 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2);
1224 processSimpleRelocation(SectionID, Offset, RelType, Value);
1226 } else if (IsMipsN32ABI || IsMipsN64ABI) {
1227 uint32_t r_type = RelType & 0xff;
1228 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1229 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE
1230 || r_type == ELF::R_MIPS_GOT_DISP) {
1231 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName);
1232 if (i != GOTSymbolOffsets.end())
1233 RE.SymOffset = i->second;
1235 RE.SymOffset = allocateGOTEntries(SectionID, 1);
1236 GOTSymbolOffsets[TargetName] = RE.SymOffset;
1239 if (Value.SymbolName)
1240 addRelocationForSymbol(RE, Value.SymbolName);
1242 addRelocationForSection(RE, Value.SectionID);
1243 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1244 if (RelType == ELF::R_PPC64_REL24) {
1245 // Determine ABI variant in use for this object.
1246 unsigned AbiVariant;
1247 Obj.getPlatformFlags(AbiVariant);
1248 AbiVariant &= ELF::EF_PPC64_ABI;
1249 // A PPC branch relocation will need a stub function if the target is
1250 // an external symbol (Symbol::ST_Unknown) or if the target address
1251 // is not within the signed 24-bits branch address.
1252 SectionEntry &Section = Sections[SectionID];
1253 uint8_t *Target = Section.getAddressWithOffset(Offset);
1254 bool RangeOverflow = false;
1255 if (SymType != SymbolRef::ST_Unknown) {
1256 if (AbiVariant != 2) {
1257 // In the ELFv1 ABI, a function call may point to the .opd entry,
1258 // so the final symbol value is calculated based on the relocation
1259 // values in the .opd section.
1260 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value))
1261 return std::move(Err);
1263 // In the ELFv2 ABI, a function symbol may provide a local entry
1264 // point, which must be used for direct calls.
1265 uint8_t SymOther = Symbol->getOther();
1266 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther);
1268 uint8_t *RelocTarget =
1269 Sections[Value.SectionID].getAddressWithOffset(Value.Addend);
1270 int32_t delta = static_cast<int32_t>(Target - RelocTarget);
1271 // If it is within 26-bits branch range, just set the branch target
1272 if (SignExtend32<26>(delta) == delta) {
1273 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1274 if (Value.SymbolName)
1275 addRelocationForSymbol(RE, Value.SymbolName);
1277 addRelocationForSection(RE, Value.SectionID);
1279 RangeOverflow = true;
1282 if (SymType == SymbolRef::ST_Unknown || RangeOverflow) {
1283 // It is an external symbol (SymbolRef::ST_Unknown) or within a range
1284 // larger than 24-bits.
1285 StubMap::const_iterator i = Stubs.find(Value);
1286 if (i != Stubs.end()) {
1287 // Symbol function stub already created, just relocate to it
1288 resolveRelocation(Section, Offset,
1289 reinterpret_cast<uint64_t>(
1290 Section.getAddressWithOffset(i->second)),
1292 DEBUG(dbgs() << " Stub function found\n");
1294 // Create a new stub function.
1295 DEBUG(dbgs() << " Create a new stub function\n");
1296 Stubs[Value] = Section.getStubOffset();
1297 uint8_t *StubTargetAddr = createStubFunction(
1298 Section.getAddressWithOffset(Section.getStubOffset()),
1300 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1301 ELF::R_PPC64_ADDR64, Value.Addend);
1303 // Generates the 64-bits address loads as exemplified in section
1304 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to
1305 // apply to the low part of the instructions, so we have to update
1306 // the offset according to the target endianness.
1307 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress();
1308 if (!IsTargetLittleEndian)
1309 StubRelocOffset += 2;
1311 RelocationEntry REhst(SectionID, StubRelocOffset + 0,
1312 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1313 RelocationEntry REhr(SectionID, StubRelocOffset + 4,
1314 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1315 RelocationEntry REh(SectionID, StubRelocOffset + 12,
1316 ELF::R_PPC64_ADDR16_HI, Value.Addend);
1317 RelocationEntry REl(SectionID, StubRelocOffset + 16,
1318 ELF::R_PPC64_ADDR16_LO, Value.Addend);
1320 if (Value.SymbolName) {
1321 addRelocationForSymbol(REhst, Value.SymbolName);
1322 addRelocationForSymbol(REhr, Value.SymbolName);
1323 addRelocationForSymbol(REh, Value.SymbolName);
1324 addRelocationForSymbol(REl, Value.SymbolName);
1326 addRelocationForSection(REhst, Value.SectionID);
1327 addRelocationForSection(REhr, Value.SectionID);
1328 addRelocationForSection(REh, Value.SectionID);
1329 addRelocationForSection(REl, Value.SectionID);
1332 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1333 Section.getAddressWithOffset(
1334 Section.getStubOffset())),
1336 Section.advanceStubOffset(getMaxStubSize());
1338 if (SymType == SymbolRef::ST_Unknown) {
1339 // Restore the TOC for external calls
1340 if (AbiVariant == 2)
1341 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1)
1343 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1)
1346 } else if (RelType == ELF::R_PPC64_TOC16 ||
1347 RelType == ELF::R_PPC64_TOC16_DS ||
1348 RelType == ELF::R_PPC64_TOC16_LO ||
1349 RelType == ELF::R_PPC64_TOC16_LO_DS ||
1350 RelType == ELF::R_PPC64_TOC16_HI ||
1351 RelType == ELF::R_PPC64_TOC16_HA) {
1352 // These relocations are supposed to subtract the TOC address from
1353 // the final value. This does not fit cleanly into the RuntimeDyld
1354 // scheme, since there may be *two* sections involved in determining
1355 // the relocation value (the section of the symbol referred to by the
1356 // relocation, and the TOC section associated with the current module).
1358 // Fortunately, these relocations are currently only ever generated
1359 // referring to symbols that themselves reside in the TOC, which means
1360 // that the two sections are actually the same. Thus they cancel out
1361 // and we can immediately resolve the relocation right now.
1363 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break;
1364 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break;
1365 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break;
1366 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break;
1367 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break;
1368 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break;
1369 default: llvm_unreachable("Wrong relocation type.");
1372 RelocationValueRef TOCValue;
1373 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue))
1374 return std::move(Err);
1375 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID)
1376 llvm_unreachable("Unsupported TOC relocation.");
1377 Value.Addend -= TOCValue.Addend;
1378 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0);
1380 // There are two ways to refer to the TOC address directly: either
1381 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are
1382 // ignored), or via any relocation that refers to the magic ".TOC."
1383 // symbols (in which case the addend is respected).
1384 if (RelType == ELF::R_PPC64_TOC) {
1385 RelType = ELF::R_PPC64_ADDR64;
1386 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1387 return std::move(Err);
1388 } else if (TargetName == ".TOC.") {
1389 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1390 return std::move(Err);
1391 Value.Addend += Addend;
1394 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1396 if (Value.SymbolName)
1397 addRelocationForSymbol(RE, Value.SymbolName);
1399 addRelocationForSection(RE, Value.SectionID);
1401 } else if (Arch == Triple::systemz &&
1402 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) {
1403 // Create function stubs for both PLT and GOT references, regardless of
1404 // whether the GOT reference is to data or code. The stub contains the
1405 // full address of the symbol, as needed by GOT references, and the
1406 // executable part only adds an overhead of 8 bytes.
1408 // We could try to conserve space by allocating the code and data
1409 // parts of the stub separately. However, as things stand, we allocate
1410 // a stub for every relocation, so using a GOT in JIT code should be
1411 // no less space efficient than using an explicit constant pool.
1412 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1413 SectionEntry &Section = Sections[SectionID];
1415 // Look for an existing stub.
1416 StubMap::const_iterator i = Stubs.find(Value);
1417 uintptr_t StubAddress;
1418 if (i != Stubs.end()) {
1419 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second));
1420 DEBUG(dbgs() << " Stub function found\n");
1422 // Create a new stub function.
1423 DEBUG(dbgs() << " Create a new stub function\n");
1425 uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1426 uintptr_t StubAlignment = getStubAlignment();
1428 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1430 unsigned StubOffset = StubAddress - BaseAddress;
1432 Stubs[Value] = StubOffset;
1433 createStubFunction((uint8_t *)StubAddress);
1434 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
1436 if (Value.SymbolName)
1437 addRelocationForSymbol(RE, Value.SymbolName);
1439 addRelocationForSection(RE, Value.SectionID);
1440 Section.advanceStubOffset(getMaxStubSize());
1443 if (RelType == ELF::R_390_GOTENT)
1444 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL,
1447 resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1448 } else if (Arch == Triple::x86_64) {
1449 if (RelType == ELF::R_X86_64_PLT32) {
1450 // The way the PLT relocations normally work is that the linker allocates
1452 // PLT and this relocation makes a PC-relative call into the PLT. The PLT
1453 // entry will then jump to an address provided by the GOT. On first call,
1455 // GOT address will point back into PLT code that resolves the symbol. After
1456 // the first call, the GOT entry points to the actual function.
1458 // For local functions we're ignoring all of that here and just replacing
1459 // the PLT32 relocation type with PC32, which will translate the relocation
1460 // into a PC-relative call directly to the function. For external symbols we
1461 // can't be sure the function will be within 2^32 bytes of the call site, so
1462 // we need to create a stub, which calls into the GOT. This case is
1463 // equivalent to the usual PLT implementation except that we use the stub
1464 // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1465 // rather than allocating a PLT section.
1466 if (Value.SymbolName) {
1467 // This is a call to an external function.
1468 // Look for an existing stub.
1469 SectionEntry &Section = Sections[SectionID];
1470 StubMap::const_iterator i = Stubs.find(Value);
1471 uintptr_t StubAddress;
1472 if (i != Stubs.end()) {
1473 StubAddress = uintptr_t(Section.getAddress()) + i->second;
1474 DEBUG(dbgs() << " Stub function found\n");
1476 // Create a new stub function (equivalent to a PLT entry).
1477 DEBUG(dbgs() << " Create a new stub function\n");
1479 uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1480 uintptr_t StubAlignment = getStubAlignment();
1482 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1484 unsigned StubOffset = StubAddress - BaseAddress;
1485 Stubs[Value] = StubOffset;
1486 createStubFunction((uint8_t *)StubAddress);
1488 // Bump our stub offset counter
1489 Section.advanceStubOffset(getMaxStubSize());
1491 // Allocate a GOT Entry
1492 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1);
1494 // The load of the GOT address has an addend of -4
1495 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4);
1497 // Fill in the value of the symbol we're targeting into the GOT
1498 addRelocationForSymbol(
1499 computeGOTOffsetRE(SectionID, GOTOffset, 0, ELF::R_X86_64_64),
1503 // Make the target call a call into the stub table.
1504 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32,
1507 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1509 addRelocationForSection(RE, Value.SectionID);
1511 } else if (RelType == ELF::R_X86_64_GOTPCREL ||
1512 RelType == ELF::R_X86_64_GOTPCRELX ||
1513 RelType == ELF::R_X86_64_REX_GOTPCRELX) {
1514 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1);
1515 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend);
1517 // Fill in the value of the symbol we're targeting into the GOT
1518 RelocationEntry RE = computeGOTOffsetRE(SectionID, GOTOffset, Value.Offset, ELF::R_X86_64_64);
1519 if (Value.SymbolName)
1520 addRelocationForSymbol(RE, Value.SymbolName);
1522 addRelocationForSection(RE, Value.SectionID);
1523 } else if (RelType == ELF::R_X86_64_PC32) {
1524 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1525 processSimpleRelocation(SectionID, Offset, RelType, Value);
1526 } else if (RelType == ELF::R_X86_64_PC64) {
1527 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset));
1528 processSimpleRelocation(SectionID, Offset, RelType, Value);
1530 processSimpleRelocation(SectionID, Offset, RelType, Value);
1533 if (Arch == Triple::x86) {
1534 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1536 processSimpleRelocation(SectionID, Offset, RelType, Value);
1541 size_t RuntimeDyldELF::getGOTEntrySize() {
1542 // We don't use the GOT in all of these cases, but it's essentially free
1543 // to put them all here.
1546 case Triple::x86_64:
1547 case Triple::aarch64:
1548 case Triple::aarch64_be:
1550 case Triple::ppc64le:
1551 case Triple::systemz:
1552 Result = sizeof(uint64_t);
1557 Result = sizeof(uint32_t);
1560 case Triple::mipsel:
1561 case Triple::mips64:
1562 case Triple::mips64el:
1563 if (IsMipsO32ABI || IsMipsN32ABI)
1564 Result = sizeof(uint32_t);
1565 else if (IsMipsN64ABI)
1566 Result = sizeof(uint64_t);
1568 llvm_unreachable("Mips ABI not handled");
1571 llvm_unreachable("Unsupported CPU type!");
1576 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned SectionID, unsigned no)
1578 (void)SectionID; // The GOT Section is the same for all section in the object file
1579 if (GOTSectionID == 0) {
1580 GOTSectionID = Sections.size();
1581 // Reserve a section id. We'll allocate the section later
1582 // once we know the total size
1583 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0));
1585 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize();
1586 CurrentGOTIndex += no;
1590 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset, uint64_t GOTOffset)
1592 // Fill in the relative address of the GOT Entry into the stub
1593 RelocationEntry GOTRE(SectionID, Offset, ELF::R_X86_64_PC32, GOTOffset);
1594 addRelocationForSection(GOTRE, GOTSectionID);
1597 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(unsigned SectionID, uint64_t GOTOffset, uint64_t SymbolOffset,
1600 (void)SectionID; // The GOT Section is the same for all section in the object file
1601 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset);
1604 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj,
1605 ObjSectionToIDMap &SectionMap) {
1607 if (!PendingRelocs.empty())
1608 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc");
1610 // If necessary, allocate the global offset table
1611 if (GOTSectionID != 0) {
1612 // Allocate memory for the section
1613 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize();
1614 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(),
1615 GOTSectionID, ".got", false);
1617 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!");
1619 Sections[GOTSectionID] =
1620 SectionEntry(".got", Addr, TotalSize, TotalSize, 0);
1623 Checker->registerSection(Obj.getFileName(), GOTSectionID);
1625 // For now, initialize all GOT entries to zero. We'll fill them in as
1626 // needed when GOT-based relocations are applied.
1627 memset(Addr, 0, TotalSize);
1628 if (IsMipsN32ABI || IsMipsN64ABI) {
1629 // To correctly resolve Mips GOT relocations, we need a mapping from
1630 // object's sections to GOTs.
1631 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
1633 if (SI->relocation_begin() != SI->relocation_end()) {
1634 section_iterator RelocatedSection = SI->getRelocatedSection();
1635 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection);
1636 assert (i != SectionMap.end());
1637 SectionToGOTMap[i->second] = GOTSectionID;
1640 GOTSymbolOffsets.clear();
1644 // Look for and record the EH frame section.
1645 ObjSectionToIDMap::iterator i, e;
1646 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1647 const SectionRef &Section = i->first;
1649 Section.getName(Name);
1650 if (Name == ".eh_frame") {
1651 UnregisteredEHFrameSections.push_back(i->second);
1657 CurrentGOTIndex = 0;
1659 return Error::success();
1662 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const {
1666 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const {
1667 if (Arch != Triple::x86_64)
1668 return true; // Conservative answer
1670 switch (R.getType()) {
1672 return true; // Conservative answer
1675 case ELF::R_X86_64_GOTPCREL:
1676 case ELF::R_X86_64_GOTPCRELX:
1677 case ELF::R_X86_64_REX_GOTPCRELX:
1678 case ELF::R_X86_64_PC32:
1679 case ELF::R_X86_64_PC64:
1680 case ELF::R_X86_64_64:
1681 // We know that these reloation types won't need a stub function. This list
1682 // can be extended as needed.