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 "llvm/ADT/IntervalMap.h"
17 #include "llvm/ADT/STLExtras.h"
18 #include "llvm/ADT/StringRef.h"
19 #include "llvm/ADT/Triple.h"
20 #include "llvm/MC/MCStreamer.h"
21 #include "llvm/Object/ELFObjectFile.h"
22 #include "llvm/Object/ObjectFile.h"
23 #include "llvm/Support/ELF.h"
24 #include "llvm/Support/Endian.h"
25 #include "llvm/Support/MemoryBuffer.h"
26 #include "llvm/Support/TargetRegistry.h"
29 using namespace llvm::object;
31 #define DEBUG_TYPE "dyld"
35 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> {
36 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
38 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
39 typedef Elf_Sym_Impl<ELFT> Elf_Sym;
40 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
41 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
43 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
45 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type;
48 DyldELFObject(MemoryBufferRef Wrapper, std::error_code &ec);
50 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
52 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr);
54 // Methods for type inquiry through isa, cast and dyn_cast
55 static inline bool classof(const Binary *v) {
56 return (isa<ELFObjectFile<ELFT>>(v) &&
57 classof(cast<ELFObjectFile<ELFT>>(v)));
59 static inline bool classof(const ELFObjectFile<ELFT> *v) {
60 return v->isDyldType();
66 // The MemoryBuffer passed into this constructor is just a wrapper around the
67 // actual memory. Ultimately, the Binary parent class will take ownership of
68 // this MemoryBuffer object but not the underlying memory.
70 DyldELFObject<ELFT>::DyldELFObject(MemoryBufferRef Wrapper, std::error_code &EC)
71 : ELFObjectFile<ELFT>(Wrapper, EC) {
72 this->isDyldELFObject = true;
76 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
78 DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
80 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
82 // This assumes the address passed in matches the target address bitness
83 // The template-based type cast handles everything else.
84 shdr->sh_addr = static_cast<addr_type>(Addr);
88 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
91 Elf_Sym *sym = const_cast<Elf_Sym *>(
92 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl()));
94 // This assumes the address passed in matches the target address bitness
95 // The template-based type cast handles everything else.
96 sym->st_value = static_cast<addr_type>(Addr);
99 class LoadedELFObjectInfo final
100 : public RuntimeDyld::LoadedObjectInfoHelper<LoadedELFObjectInfo> {
102 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
103 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
105 OwningBinary<ObjectFile>
106 getObjectForDebug(const ObjectFile &Obj) const override;
109 template <typename ELFT>
110 std::unique_ptr<DyldELFObject<ELFT>>
111 createRTDyldELFObject(MemoryBufferRef Buffer,
112 const ObjectFile &SourceObject,
113 const LoadedELFObjectInfo &L,
114 std::error_code &ec) {
115 typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
116 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type;
118 std::unique_ptr<DyldELFObject<ELFT>> Obj =
119 llvm::make_unique<DyldELFObject<ELFT>>(Buffer, ec);
121 // Iterate over all sections in the object.
122 auto SI = SourceObject.section_begin();
123 for (const auto &Sec : Obj->sections()) {
124 StringRef SectionName;
125 Sec.getName(SectionName);
126 if (SectionName != "") {
127 DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
128 Elf_Shdr *shdr = const_cast<Elf_Shdr *>(
129 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
131 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) {
132 // This assumes that the address passed in matches the target address
133 // bitness. The template-based type cast handles everything else.
134 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr);
143 OwningBinary<ObjectFile> createELFDebugObject(const ObjectFile &Obj,
144 const LoadedELFObjectInfo &L) {
145 assert(Obj.isELF() && "Not an ELF object file.");
147 std::unique_ptr<MemoryBuffer> Buffer =
148 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName());
152 std::unique_ptr<ObjectFile> DebugObj;
153 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) {
154 typedef ELFType<support::little, false> ELF32LE;
155 DebugObj = createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L,
157 } else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) {
158 typedef ELFType<support::big, false> ELF32BE;
159 DebugObj = createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L,
161 } else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) {
162 typedef ELFType<support::big, true> ELF64BE;
163 DebugObj = createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L,
165 } else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) {
166 typedef ELFType<support::little, true> ELF64LE;
167 DebugObj = createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L,
170 llvm_unreachable("Unexpected ELF format");
172 assert(!ec && "Could not construct copy ELF object file");
174 return OwningBinary<ObjectFile>(std::move(DebugObj), std::move(Buffer));
177 OwningBinary<ObjectFile>
178 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const {
179 return createELFDebugObject(Obj, *this);
182 } // anonymous namespace
186 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr,
187 RuntimeDyld::SymbolResolver &Resolver)
188 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {}
189 RuntimeDyldELF::~RuntimeDyldELF() {}
191 void RuntimeDyldELF::registerEHFrames() {
192 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
193 SID EHFrameSID = UnregisteredEHFrameSections[i];
194 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
195 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
196 size_t EHFrameSize = Sections[EHFrameSID].getSize();
197 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
198 RegisteredEHFrameSections.push_back(EHFrameSID);
200 UnregisteredEHFrameSections.clear();
203 void RuntimeDyldELF::deregisterEHFrames() {
204 for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) {
205 SID EHFrameSID = RegisteredEHFrameSections[i];
206 uint8_t *EHFrameAddr = Sections[EHFrameSID].getAddress();
207 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].getLoadAddress();
208 size_t EHFrameSize = Sections[EHFrameSID].getSize();
209 MemMgr.deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
211 RegisteredEHFrameSections.clear();
214 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
215 RuntimeDyldELF::loadObject(const object::ObjectFile &O) {
216 if (auto ObjSectionToIDOrErr = loadObjectImpl(O))
217 return llvm::make_unique<LoadedELFObjectInfo>(*this, *ObjSectionToIDOrErr);
220 raw_string_ostream ErrStream(ErrorStr);
221 logAllUnhandledErrors(ObjSectionToIDOrErr.takeError(), ErrStream, "");
226 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
227 uint64_t Offset, uint64_t Value,
228 uint32_t Type, int64_t Addend,
229 uint64_t SymOffset) {
232 llvm_unreachable("Relocation type not implemented yet!");
234 case ELF::R_X86_64_64: {
235 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) =
237 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
238 << format("%p\n", Section.getAddressWithOffset(Offset)));
241 case ELF::R_X86_64_32:
242 case ELF::R_X86_64_32S: {
244 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
245 (Type == ELF::R_X86_64_32S &&
246 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
247 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
248 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
250 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at "
251 << format("%p\n", Section.getAddressWithOffset(Offset)));
254 case ELF::R_X86_64_PC8: {
255 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
256 int64_t RealOffset = Value + Addend - FinalAddress;
257 assert(isInt<8>(RealOffset));
258 int8_t TruncOffset = (RealOffset & 0xFF);
259 Section.getAddress()[Offset] = TruncOffset;
262 case ELF::R_X86_64_PC32: {
263 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
264 int64_t RealOffset = Value + Addend - FinalAddress;
265 assert(isInt<32>(RealOffset));
266 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
267 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
271 case ELF::R_X86_64_PC64: {
272 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
273 int64_t RealOffset = Value + Addend - FinalAddress;
274 support::ulittle64_t::ref(Section.getAddressWithOffset(Offset)) =
281 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
282 uint64_t Offset, uint32_t Value,
283 uint32_t Type, int32_t Addend) {
285 case ELF::R_386_32: {
286 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
290 case ELF::R_386_PC32: {
291 uint32_t FinalAddress =
292 Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
293 uint32_t RealOffset = Value + Addend - FinalAddress;
294 support::ulittle32_t::ref(Section.getAddressWithOffset(Offset)) =
299 // There are other relocation types, but it appears these are the
300 // only ones currently used by the LLVM ELF object writer
301 llvm_unreachable("Relocation type not implemented yet!");
306 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
307 uint64_t Offset, uint64_t Value,
308 uint32_t Type, int64_t Addend) {
309 uint32_t *TargetPtr =
310 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
311 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
313 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
314 << format("%llx", Section.getAddressWithOffset(Offset))
315 << " FinalAddress: 0x" << format("%llx", FinalAddress)
316 << " Value: 0x" << format("%llx", Value) << " Type: 0x"
317 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend)
322 llvm_unreachable("Relocation type not implemented yet!");
324 case ELF::R_AARCH64_ABS64: {
325 uint64_t *TargetPtr =
326 reinterpret_cast<uint64_t *>(Section.getAddressWithOffset(Offset));
327 *TargetPtr = Value + Addend;
330 case ELF::R_AARCH64_PREL32: {
331 uint64_t Result = Value + Addend - FinalAddress;
332 assert(static_cast<int64_t>(Result) >= INT32_MIN &&
333 static_cast<int64_t>(Result) <= UINT32_MAX);
334 *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU);
337 case ELF::R_AARCH64_CALL26: // fallthrough
338 case ELF::R_AARCH64_JUMP26: {
339 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
341 uint64_t BranchImm = Value + Addend - FinalAddress;
343 // "Check that -2^27 <= result < 2^27".
344 assert(isInt<28>(BranchImm));
346 // AArch64 code is emitted with .rela relocations. The data already in any
347 // bits affected by the relocation on entry is garbage.
348 *TargetPtr &= 0xfc000000U;
349 // Immediate goes in bits 25:0 of B and BL.
350 *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2;
353 case ELF::R_AARCH64_MOVW_UABS_G3: {
354 uint64_t Result = Value + Addend;
356 // AArch64 code is emitted with .rela relocations. The data already in any
357 // bits affected by the relocation on entry is garbage.
358 *TargetPtr &= 0xffe0001fU;
359 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
360 *TargetPtr |= Result >> (48 - 5);
361 // Shift must be "lsl #48", in bits 22:21
362 assert((*TargetPtr >> 21 & 0x3) == 3 && "invalid shift for relocation");
365 case ELF::R_AARCH64_MOVW_UABS_G2_NC: {
366 uint64_t Result = Value + Addend;
368 // AArch64 code is emitted with .rela relocations. The data already in any
369 // bits affected by the relocation on entry is garbage.
370 *TargetPtr &= 0xffe0001fU;
371 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
372 *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5));
373 // Shift must be "lsl #32", in bits 22:21
374 assert((*TargetPtr >> 21 & 0x3) == 2 && "invalid shift for relocation");
377 case ELF::R_AARCH64_MOVW_UABS_G1_NC: {
378 uint64_t Result = Value + Addend;
380 // AArch64 code is emitted with .rela relocations. The data already in any
381 // bits affected by the relocation on entry is garbage.
382 *TargetPtr &= 0xffe0001fU;
383 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
384 *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5));
385 // Shift must be "lsl #16", in bits 22:2
386 assert((*TargetPtr >> 21 & 0x3) == 1 && "invalid shift for relocation");
389 case ELF::R_AARCH64_MOVW_UABS_G0_NC: {
390 uint64_t Result = Value + Addend;
392 // AArch64 code is emitted with .rela relocations. The data already in any
393 // bits affected by the relocation on entry is garbage.
394 *TargetPtr &= 0xffe0001fU;
395 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
396 *TargetPtr |= ((Result & 0xffffU) << 5);
397 // Shift must be "lsl #0", in bits 22:21.
398 assert((*TargetPtr >> 21 & 0x3) == 0 && "invalid shift for relocation");
401 case ELF::R_AARCH64_ADR_PREL_PG_HI21: {
402 // Operation: Page(S+A) - Page(P)
404 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL);
406 // Check that -2^32 <= X < 2^32
407 assert(isInt<33>(Result) && "overflow check failed for relocation");
409 // AArch64 code is emitted with .rela relocations. The data already in any
410 // bits affected by the relocation on entry is garbage.
411 *TargetPtr &= 0x9f00001fU;
412 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken
413 // from bits 32:12 of X.
414 *TargetPtr |= ((Result & 0x3000U) << (29 - 12));
415 *TargetPtr |= ((Result & 0x1ffffc000ULL) >> (14 - 5));
418 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: {
420 uint64_t Result = Value + Addend;
422 // AArch64 code is emitted with .rela relocations. The data already in any
423 // bits affected by the relocation on entry is garbage.
424 *TargetPtr &= 0xffc003ffU;
425 // Immediate goes in bits 21:10 of LD/ST instruction, taken
426 // from bits 11:2 of X
427 *TargetPtr |= ((Result & 0xffc) << (10 - 2));
430 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: {
432 uint64_t Result = Value + Addend;
434 // AArch64 code is emitted with .rela relocations. The data already in any
435 // bits affected by the relocation on entry is garbage.
436 *TargetPtr &= 0xffc003ffU;
437 // Immediate goes in bits 21:10 of LD/ST instruction, taken
438 // from bits 11:3 of X
439 *TargetPtr |= ((Result & 0xff8) << (10 - 3));
445 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
446 uint64_t Offset, uint32_t Value,
447 uint32_t Type, int32_t Addend) {
448 // TODO: Add Thumb relocations.
449 uint32_t *TargetPtr =
450 reinterpret_cast<uint32_t *>(Section.getAddressWithOffset(Offset));
451 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset) & 0xFFFFFFFF;
454 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
455 << Section.getAddressWithOffset(Offset)
456 << " FinalAddress: " << format("%p", FinalAddress) << " Value: "
457 << format("%x", Value) << " Type: " << format("%x", Type)
458 << " Addend: " << format("%x", Addend) << "\n");
462 llvm_unreachable("Not implemented relocation type!");
464 case ELF::R_ARM_NONE:
466 case ELF::R_ARM_PREL31:
467 case ELF::R_ARM_TARGET1:
468 case ELF::R_ARM_ABS32:
471 // Write first 16 bit of 32 bit value to the mov instruction.
472 // Last 4 bit should be shifted.
473 case ELF::R_ARM_MOVW_ABS_NC:
474 case ELF::R_ARM_MOVT_ABS:
475 if (Type == ELF::R_ARM_MOVW_ABS_NC)
476 Value = Value & 0xFFFF;
477 else if (Type == ELF::R_ARM_MOVT_ABS)
478 Value = (Value >> 16) & 0xFFFF;
479 *TargetPtr &= ~0x000F0FFF;
480 *TargetPtr |= Value & 0xFFF;
481 *TargetPtr |= ((Value >> 12) & 0xF) << 16;
483 // Write 24 bit relative value to the branch instruction.
484 case ELF::R_ARM_PC24: // Fall through.
485 case ELF::R_ARM_CALL: // Fall through.
486 case ELF::R_ARM_JUMP24:
487 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
488 RelValue = (RelValue & 0x03FFFFFC) >> 2;
489 assert((*TargetPtr & 0xFFFFFF) == 0xFFFFFE);
490 *TargetPtr &= 0xFF000000;
491 *TargetPtr |= RelValue;
496 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section,
497 uint64_t Offset, uint32_t Value,
498 uint32_t Type, int32_t Addend) {
499 uint8_t *TargetPtr = Section.getAddressWithOffset(Offset);
502 DEBUG(dbgs() << "resolveMIPSRelocation, LocalAddress: "
503 << Section.getAddressWithOffset(Offset) << " FinalAddress: "
504 << format("%p", Section.getLoadAddressWithOffset(Offset))
505 << " Value: " << format("%x", Value)
506 << " Type: " << format("%x", Type)
507 << " Addend: " << format("%x", Addend) << "\n");
509 uint32_t Insn = readBytesUnaligned(TargetPtr, 4);
513 llvm_unreachable("Not implemented relocation type!");
516 writeBytesUnaligned(Value, TargetPtr, 4);
520 Insn |= (Value & 0x0fffffff) >> 2;
521 writeBytesUnaligned(Insn, TargetPtr, 4);
523 case ELF::R_MIPS_HI16:
524 // Get the higher 16-bits. Also add 1 if bit 15 is 1.
526 Insn |= ((Value + 0x8000) >> 16) & 0xffff;
527 writeBytesUnaligned(Insn, TargetPtr, 4);
529 case ELF::R_MIPS_LO16:
531 Insn |= Value & 0xffff;
532 writeBytesUnaligned(Insn, TargetPtr, 4);
534 case ELF::R_MIPS_PC32: {
535 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
536 writeBytesUnaligned(Value - FinalAddress, (uint8_t *)TargetPtr, 4);
539 case ELF::R_MIPS_PC16: {
540 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
542 Insn |= ((Value - FinalAddress) >> 2) & 0xffff;
543 writeBytesUnaligned(Insn, TargetPtr, 4);
546 case ELF::R_MIPS_PC19_S2: {
547 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
549 Insn |= ((Value - (FinalAddress & ~0x3)) >> 2) & 0x7ffff;
550 writeBytesUnaligned(Insn, TargetPtr, 4);
553 case ELF::R_MIPS_PC21_S2: {
554 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
556 Insn |= ((Value - FinalAddress) >> 2) & 0x1fffff;
557 writeBytesUnaligned(Insn, TargetPtr, 4);
560 case ELF::R_MIPS_PC26_S2: {
561 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
563 Insn |= ((Value - FinalAddress) >> 2) & 0x3ffffff;
564 writeBytesUnaligned(Insn, TargetPtr, 4);
567 case ELF::R_MIPS_PCHI16: {
568 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
570 Insn |= ((Value - FinalAddress + 0x8000) >> 16) & 0xffff;
571 writeBytesUnaligned(Insn, TargetPtr, 4);
574 case ELF::R_MIPS_PCLO16: {
575 uint32_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
577 Insn |= (Value - FinalAddress) & 0xffff;
578 writeBytesUnaligned(Insn, TargetPtr, 4);
584 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) {
585 if (Arch == Triple::UnknownArch ||
586 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) {
587 IsMipsO32ABI = false;
588 IsMipsN64ABI = false;
592 Obj.getPlatformFlags(AbiVariant);
593 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32;
594 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips");
595 if (AbiVariant & ELF::EF_MIPS_ABI2)
596 llvm_unreachable("Mips N32 ABI is not supported yet");
599 void RuntimeDyldELF::resolveMIPS64Relocation(const SectionEntry &Section,
600 uint64_t Offset, uint64_t Value,
601 uint32_t Type, int64_t Addend,
604 uint32_t r_type = Type & 0xff;
605 uint32_t r_type2 = (Type >> 8) & 0xff;
606 uint32_t r_type3 = (Type >> 16) & 0xff;
608 // RelType is used to keep information for which relocation type we are
609 // applying relocation.
610 uint32_t RelType = r_type;
611 int64_t CalculatedValue = evaluateMIPS64Relocation(Section, Offset, Value,
613 SymOffset, SectionID);
614 if (r_type2 != ELF::R_MIPS_NONE) {
616 CalculatedValue = evaluateMIPS64Relocation(Section, Offset, 0, RelType,
617 CalculatedValue, SymOffset,
620 if (r_type3 != ELF::R_MIPS_NONE) {
622 CalculatedValue = evaluateMIPS64Relocation(Section, Offset, 0, RelType,
623 CalculatedValue, SymOffset,
626 applyMIPS64Relocation(Section.getAddressWithOffset(Offset), CalculatedValue,
631 RuntimeDyldELF::evaluateMIPS64Relocation(const SectionEntry &Section,
632 uint64_t Offset, uint64_t Value,
633 uint32_t Type, int64_t Addend,
634 uint64_t SymOffset, SID SectionID) {
636 DEBUG(dbgs() << "evaluateMIPS64Relocation, LocalAddress: 0x"
637 << format("%llx", Section.getAddressWithOffset(Offset))
638 << " FinalAddress: 0x"
639 << format("%llx", Section.getLoadAddressWithOffset(Offset))
640 << " Value: 0x" << format("%llx", Value) << " Type: 0x"
641 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend)
642 << " SymOffset: " << format("%x", SymOffset) << "\n");
646 llvm_unreachable("Not implemented relocation type!");
648 case ELF::R_MIPS_JALR:
649 case ELF::R_MIPS_NONE:
653 return Value + Addend;
655 return ((Value + Addend) >> 2) & 0x3ffffff;
656 case ELF::R_MIPS_GPREL16: {
657 uint64_t GOTAddr = getSectionLoadAddress(SectionToGOTMap[SectionID]);
658 return Value + Addend - (GOTAddr + 0x7ff0);
660 case ELF::R_MIPS_SUB:
661 return Value - Addend;
662 case ELF::R_MIPS_HI16:
663 // Get the higher 16-bits. Also add 1 if bit 15 is 1.
664 return ((Value + Addend + 0x8000) >> 16) & 0xffff;
665 case ELF::R_MIPS_LO16:
666 return (Value + Addend) & 0xffff;
667 case ELF::R_MIPS_CALL16:
668 case ELF::R_MIPS_GOT_DISP:
669 case ELF::R_MIPS_GOT_PAGE: {
670 uint8_t *LocalGOTAddr =
671 getSectionAddress(SectionToGOTMap[SectionID]) + SymOffset;
672 uint64_t GOTEntry = readBytesUnaligned(LocalGOTAddr, 8);
675 if (Type == ELF::R_MIPS_GOT_PAGE)
676 Value = (Value + 0x8000) & ~0xffff;
679 assert(GOTEntry == Value &&
680 "GOT entry has two different addresses.");
682 writeBytesUnaligned(Value, LocalGOTAddr, 8);
684 return (SymOffset - 0x7ff0) & 0xffff;
686 case ELF::R_MIPS_GOT_OFST: {
687 int64_t page = (Value + Addend + 0x8000) & ~0xffff;
688 return (Value + Addend - page) & 0xffff;
690 case ELF::R_MIPS_GPREL32: {
691 uint64_t GOTAddr = getSectionLoadAddress(SectionToGOTMap[SectionID]);
692 return Value + Addend - (GOTAddr + 0x7ff0);
694 case ELF::R_MIPS_PC16: {
695 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
696 return ((Value + Addend - FinalAddress) >> 2) & 0xffff;
698 case ELF::R_MIPS_PC32: {
699 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
700 return Value + Addend - FinalAddress;
702 case ELF::R_MIPS_PC18_S3: {
703 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
704 return ((Value + Addend - (FinalAddress & ~0x7)) >> 3) & 0x3ffff;
706 case ELF::R_MIPS_PC19_S2: {
707 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
708 return ((Value + Addend - (FinalAddress & ~0x3)) >> 2) & 0x7ffff;
710 case ELF::R_MIPS_PC21_S2: {
711 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
712 return ((Value + Addend - FinalAddress) >> 2) & 0x1fffff;
714 case ELF::R_MIPS_PC26_S2: {
715 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
716 return ((Value + Addend - FinalAddress) >> 2) & 0x3ffffff;
718 case ELF::R_MIPS_PCHI16: {
719 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
720 return ((Value + Addend - FinalAddress + 0x8000) >> 16) & 0xffff;
722 case ELF::R_MIPS_PCLO16: {
723 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
724 return (Value + Addend - FinalAddress) & 0xffff;
730 void RuntimeDyldELF::applyMIPS64Relocation(uint8_t *TargetPtr,
731 int64_t CalculatedValue,
733 uint32_t Insn = readBytesUnaligned(TargetPtr, 4);
739 case ELF::R_MIPS_GPREL32:
740 case ELF::R_MIPS_PC32:
741 writeBytesUnaligned(CalculatedValue & 0xffffffff, TargetPtr, 4);
744 case ELF::R_MIPS_SUB:
745 writeBytesUnaligned(CalculatedValue, TargetPtr, 8);
748 case ELF::R_MIPS_PC26_S2:
749 Insn = (Insn & 0xfc000000) | CalculatedValue;
750 writeBytesUnaligned(Insn, TargetPtr, 4);
752 case ELF::R_MIPS_GPREL16:
753 Insn = (Insn & 0xffff0000) | (CalculatedValue & 0xffff);
754 writeBytesUnaligned(Insn, TargetPtr, 4);
756 case ELF::R_MIPS_HI16:
757 case ELF::R_MIPS_LO16:
758 case ELF::R_MIPS_PCHI16:
759 case ELF::R_MIPS_PCLO16:
760 case ELF::R_MIPS_PC16:
761 case ELF::R_MIPS_CALL16:
762 case ELF::R_MIPS_GOT_DISP:
763 case ELF::R_MIPS_GOT_PAGE:
764 case ELF::R_MIPS_GOT_OFST:
765 Insn = (Insn & 0xffff0000) | CalculatedValue;
766 writeBytesUnaligned(Insn, TargetPtr, 4);
768 case ELF::R_MIPS_PC18_S3:
769 Insn = (Insn & 0xfffc0000) | CalculatedValue;
770 writeBytesUnaligned(Insn, TargetPtr, 4);
772 case ELF::R_MIPS_PC19_S2:
773 Insn = (Insn & 0xfff80000) | CalculatedValue;
774 writeBytesUnaligned(Insn, TargetPtr, 4);
776 case ELF::R_MIPS_PC21_S2:
777 Insn = (Insn & 0xffe00000) | CalculatedValue;
778 writeBytesUnaligned(Insn, TargetPtr, 4);
783 // Return the .TOC. section and offset.
784 Error RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj,
785 ObjSectionToIDMap &LocalSections,
786 RelocationValueRef &Rel) {
787 // Set a default SectionID in case we do not find a TOC section below.
788 // This may happen for references to TOC base base (sym@toc, .odp
789 // relocation) without a .toc directive. In this case just use the
790 // first section (which is usually the .odp) since the code won't
791 // reference the .toc base directly.
792 Rel.SymbolName = nullptr;
795 // The TOC consists of sections .got, .toc, .tocbss, .plt in that
796 // order. The TOC starts where the first of these sections starts.
797 for (auto &Section: Obj.sections()) {
798 StringRef SectionName;
799 if (auto EC = Section.getName(SectionName))
800 return errorCodeToError(EC);
802 if (SectionName == ".got"
803 || SectionName == ".toc"
804 || SectionName == ".tocbss"
805 || SectionName == ".plt") {
806 if (auto SectionIDOrErr =
807 findOrEmitSection(Obj, Section, false, LocalSections))
808 Rel.SectionID = *SectionIDOrErr;
810 return SectionIDOrErr.takeError();
815 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
816 // thus permitting a full 64 Kbytes segment.
819 return Error::success();
822 // Returns the sections and offset associated with the ODP entry referenced
824 Error RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
825 ObjSectionToIDMap &LocalSections,
826 RelocationValueRef &Rel) {
827 // Get the ELF symbol value (st_value) to compare with Relocation offset in
829 for (section_iterator si = Obj.section_begin(), se = Obj.section_end();
831 section_iterator RelSecI = si->getRelocatedSection();
832 if (RelSecI == Obj.section_end())
835 StringRef RelSectionName;
836 if (auto EC = RelSecI->getName(RelSectionName))
837 return errorCodeToError(EC);
839 if (RelSectionName != ".opd")
842 for (elf_relocation_iterator i = si->relocation_begin(),
843 e = si->relocation_end();
845 // The R_PPC64_ADDR64 relocation indicates the first field
847 uint64_t TypeFunc = i->getType();
848 if (TypeFunc != ELF::R_PPC64_ADDR64) {
853 uint64_t TargetSymbolOffset = i->getOffset();
854 symbol_iterator TargetSymbol = i->getSymbol();
856 if (auto AddendOrErr = i->getAddend())
857 Addend = *AddendOrErr;
859 return errorCodeToError(AddendOrErr.getError());
865 // Just check if following relocation is a R_PPC64_TOC
866 uint64_t TypeTOC = i->getType();
867 if (TypeTOC != ELF::R_PPC64_TOC)
870 // Finally compares the Symbol value and the target symbol offset
871 // to check if this .opd entry refers to the symbol the relocation
873 if (Rel.Addend != (int64_t)TargetSymbolOffset)
876 section_iterator TSI = Obj.section_end();
877 if (auto TSIOrErr = TargetSymbol->getSection())
880 return TSIOrErr.takeError();
881 assert(TSI != Obj.section_end() && "TSI should refer to a valid section");
883 bool IsCode = TSI->isText();
884 if (auto SectionIDOrErr = findOrEmitSection(Obj, *TSI, IsCode,
886 Rel.SectionID = *SectionIDOrErr;
888 return SectionIDOrErr.takeError();
889 Rel.Addend = (intptr_t)Addend;
890 return Error::success();
893 llvm_unreachable("Attempting to get address of ODP entry!");
896 // Relocation masks following the #lo(value), #hi(value), #ha(value),
897 // #higher(value), #highera(value), #highest(value), and #highesta(value)
898 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi
901 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; }
903 static inline uint16_t applyPPChi(uint64_t value) {
904 return (value >> 16) & 0xffff;
907 static inline uint16_t applyPPCha (uint64_t value) {
908 return ((value + 0x8000) >> 16) & 0xffff;
911 static inline uint16_t applyPPChigher(uint64_t value) {
912 return (value >> 32) & 0xffff;
915 static inline uint16_t applyPPChighera (uint64_t value) {
916 return ((value + 0x8000) >> 32) & 0xffff;
919 static inline uint16_t applyPPChighest(uint64_t value) {
920 return (value >> 48) & 0xffff;
923 static inline uint16_t applyPPChighesta (uint64_t value) {
924 return ((value + 0x8000) >> 48) & 0xffff;
927 void RuntimeDyldELF::resolvePPC32Relocation(const SectionEntry &Section,
928 uint64_t Offset, uint64_t Value,
929 uint32_t Type, int64_t Addend) {
930 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
933 llvm_unreachable("Relocation type not implemented yet!");
935 case ELF::R_PPC_ADDR16_LO:
936 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
938 case ELF::R_PPC_ADDR16_HI:
939 writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
941 case ELF::R_PPC_ADDR16_HA:
942 writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
947 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
948 uint64_t Offset, uint64_t Value,
949 uint32_t Type, int64_t Addend) {
950 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
953 llvm_unreachable("Relocation type not implemented yet!");
955 case ELF::R_PPC64_ADDR16:
956 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
958 case ELF::R_PPC64_ADDR16_DS:
959 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
961 case ELF::R_PPC64_ADDR16_LO:
962 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
964 case ELF::R_PPC64_ADDR16_LO_DS:
965 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
967 case ELF::R_PPC64_ADDR16_HI:
968 writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
970 case ELF::R_PPC64_ADDR16_HA:
971 writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
973 case ELF::R_PPC64_ADDR16_HIGHER:
974 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend));
976 case ELF::R_PPC64_ADDR16_HIGHERA:
977 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend));
979 case ELF::R_PPC64_ADDR16_HIGHEST:
980 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend));
982 case ELF::R_PPC64_ADDR16_HIGHESTA:
983 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend));
985 case ELF::R_PPC64_ADDR14: {
986 assert(((Value + Addend) & 3) == 0);
987 // Preserve the AA/LK bits in the branch instruction
988 uint8_t aalk = *(LocalAddress + 3);
989 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
991 case ELF::R_PPC64_REL16_LO: {
992 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
993 uint64_t Delta = Value - FinalAddress + Addend;
994 writeInt16BE(LocalAddress, applyPPClo(Delta));
996 case ELF::R_PPC64_REL16_HI: {
997 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
998 uint64_t Delta = Value - FinalAddress + Addend;
999 writeInt16BE(LocalAddress, applyPPChi(Delta));
1001 case ELF::R_PPC64_REL16_HA: {
1002 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
1003 uint64_t Delta = Value - FinalAddress + Addend;
1004 writeInt16BE(LocalAddress, applyPPCha(Delta));
1006 case ELF::R_PPC64_ADDR32: {
1007 int32_t Result = static_cast<int32_t>(Value + Addend);
1008 if (SignExtend32<32>(Result) != Result)
1009 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
1010 writeInt32BE(LocalAddress, Result);
1012 case ELF::R_PPC64_REL24: {
1013 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
1014 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
1015 if (SignExtend32<26>(delta) != delta)
1016 llvm_unreachable("Relocation R_PPC64_REL24 overflow");
1017 // Generates a 'bl <address>' instruction
1018 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
1020 case ELF::R_PPC64_REL32: {
1021 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
1022 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
1023 if (SignExtend32<32>(delta) != delta)
1024 llvm_unreachable("Relocation R_PPC64_REL32 overflow");
1025 writeInt32BE(LocalAddress, delta);
1027 case ELF::R_PPC64_REL64: {
1028 uint64_t FinalAddress = Section.getLoadAddressWithOffset(Offset);
1029 uint64_t Delta = Value - FinalAddress + Addend;
1030 writeInt64BE(LocalAddress, Delta);
1032 case ELF::R_PPC64_ADDR64:
1033 writeInt64BE(LocalAddress, Value + Addend);
1038 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
1039 uint64_t Offset, uint64_t Value,
1040 uint32_t Type, int64_t Addend) {
1041 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);
1044 llvm_unreachable("Relocation type not implemented yet!");
1046 case ELF::R_390_PC16DBL:
1047 case ELF::R_390_PLT16DBL: {
1048 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
1049 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
1050 writeInt16BE(LocalAddress, Delta / 2);
1053 case ELF::R_390_PC32DBL:
1054 case ELF::R_390_PLT32DBL: {
1055 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
1056 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
1057 writeInt32BE(LocalAddress, Delta / 2);
1060 case ELF::R_390_PC32: {
1061 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
1062 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
1063 writeInt32BE(LocalAddress, Delta);
1067 writeInt64BE(LocalAddress, Value + Addend);
1069 case ELF::R_390_PC64: {
1070 int64_t Delta = (Value + Addend) - Section.getLoadAddressWithOffset(Offset);
1071 writeInt64BE(LocalAddress, Delta);
1077 // The target location for the relocation is described by RE.SectionID and
1078 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
1079 // SectionEntry has three members describing its location.
1080 // SectionEntry::Address is the address at which the section has been loaded
1081 // into memory in the current (host) process. SectionEntry::LoadAddress is the
1082 // address that the section will have in the target process.
1083 // SectionEntry::ObjAddress is the address of the bits for this section in the
1084 // original emitted object image (also in the current address space).
1086 // Relocations will be applied as if the section were loaded at
1087 // SectionEntry::LoadAddress, but they will be applied at an address based
1088 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to
1089 // Target memory contents if they are required for value calculations.
1091 // The Value parameter here is the load address of the symbol for the
1092 // relocation to be applied. For relocations which refer to symbols in the
1093 // current object Value will be the LoadAddress of the section in which
1094 // the symbol resides (RE.Addend provides additional information about the
1095 // symbol location). For external symbols, Value will be the address of the
1096 // symbol in the target address space.
1097 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
1099 const SectionEntry &Section = Sections[RE.SectionID];
1100 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
1101 RE.SymOffset, RE.SectionID);
1104 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
1105 uint64_t Offset, uint64_t Value,
1106 uint32_t Type, int64_t Addend,
1107 uint64_t SymOffset, SID SectionID) {
1109 case Triple::x86_64:
1110 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
1113 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
1114 (uint32_t)(Addend & 0xffffffffL));
1116 case Triple::aarch64:
1117 case Triple::aarch64_be:
1118 resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
1120 case Triple::arm: // Fall through.
1123 case Triple::thumbeb:
1124 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
1125 (uint32_t)(Addend & 0xffffffffL));
1127 case Triple::mips: // Fall through.
1128 case Triple::mipsel:
1129 case Triple::mips64:
1130 case Triple::mips64el:
1132 resolveMIPSRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL),
1133 Type, (uint32_t)(Addend & 0xffffffffL));
1134 else if (IsMipsN64ABI)
1135 resolveMIPS64Relocation(Section, Offset, Value, Type, Addend, SymOffset,
1138 llvm_unreachable("Mips ABI not handled");
1141 resolvePPC32Relocation(Section, Offset, Value, Type, Addend);
1143 case Triple::ppc64: // Fall through.
1144 case Triple::ppc64le:
1145 resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
1147 case Triple::systemz:
1148 resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
1151 llvm_unreachable("Unsupported CPU type!");
1155 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const {
1156 return (void *)(Sections[SectionID].getObjAddress() + Offset);
1159 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) {
1160 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
1161 if (Value.SymbolName)
1162 addRelocationForSymbol(RE, Value.SymbolName);
1164 addRelocationForSection(RE, Value.SectionID);
1167 uint32_t RuntimeDyldELF::getMatchingLoRelocation(uint32_t RelType,
1168 bool IsLocal) const {
1170 case ELF::R_MICROMIPS_GOT16:
1172 return ELF::R_MICROMIPS_LO16;
1174 case ELF::R_MICROMIPS_HI16:
1175 return ELF::R_MICROMIPS_LO16;
1176 case ELF::R_MIPS_GOT16:
1178 return ELF::R_MIPS_LO16;
1180 case ELF::R_MIPS_HI16:
1181 return ELF::R_MIPS_LO16;
1182 case ELF::R_MIPS_PCHI16:
1183 return ELF::R_MIPS_PCLO16;
1187 return ELF::R_MIPS_NONE;
1190 Expected<relocation_iterator>
1191 RuntimeDyldELF::processRelocationRef(
1192 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O,
1193 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) {
1194 const auto &Obj = cast<ELFObjectFileBase>(O);
1195 uint64_t RelType = RelI->getType();
1196 ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend();
1197 int64_t Addend = AddendOrErr ? *AddendOrErr : 0;
1198 elf_symbol_iterator Symbol = RelI->getSymbol();
1200 // Obtain the symbol name which is referenced in the relocation
1201 StringRef TargetName;
1202 if (Symbol != Obj.symbol_end()) {
1203 if (auto TargetNameOrErr = Symbol->getName())
1204 TargetName = *TargetNameOrErr;
1206 return TargetNameOrErr.takeError();
1208 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend
1209 << " TargetName: " << TargetName << "\n");
1210 RelocationValueRef Value;
1211 // First search for the symbol in the local symbol table
1212 SymbolRef::Type SymType = SymbolRef::ST_Unknown;
1214 // Search for the symbol in the global symbol table
1215 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end();
1216 if (Symbol != Obj.symbol_end()) {
1217 gsi = GlobalSymbolTable.find(TargetName.data());
1218 Expected<SymbolRef::Type> SymTypeOrErr = Symbol->getType();
1219 if (!SymTypeOrErr) {
1221 raw_string_ostream OS(Buf);
1222 logAllUnhandledErrors(SymTypeOrErr.takeError(), OS, "");
1224 report_fatal_error(Buf);
1226 SymType = *SymTypeOrErr;
1228 if (gsi != GlobalSymbolTable.end()) {
1229 const auto &SymInfo = gsi->second;
1230 Value.SectionID = SymInfo.getSectionID();
1231 Value.Offset = SymInfo.getOffset();
1232 Value.Addend = SymInfo.getOffset() + Addend;
1235 case SymbolRef::ST_Debug: {
1236 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
1237 // and can be changed by another developers. Maybe best way is add
1238 // a new symbol type ST_Section to SymbolRef and use it.
1239 auto SectionOrErr = Symbol->getSection();
1240 if (!SectionOrErr) {
1242 raw_string_ostream OS(Buf);
1243 logAllUnhandledErrors(SectionOrErr.takeError(), OS, "");
1245 report_fatal_error(Buf);
1247 section_iterator si = *SectionOrErr;
1248 if (si == Obj.section_end())
1249 llvm_unreachable("Symbol section not found, bad object file format!");
1250 DEBUG(dbgs() << "\t\tThis is section symbol\n");
1251 bool isCode = si->isText();
1252 if (auto SectionIDOrErr = findOrEmitSection(Obj, (*si), isCode,
1254 Value.SectionID = *SectionIDOrErr;
1256 return SectionIDOrErr.takeError();
1257 Value.Addend = Addend;
1260 case SymbolRef::ST_Data:
1261 case SymbolRef::ST_Unknown: {
1262 Value.SymbolName = TargetName.data();
1263 Value.Addend = Addend;
1265 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
1266 // will manifest here as a NULL symbol name.
1267 // We can set this as a valid (but empty) symbol name, and rely
1268 // on addRelocationForSymbol to handle this.
1269 if (!Value.SymbolName)
1270 Value.SymbolName = "";
1274 llvm_unreachable("Unresolved symbol type!");
1279 uint64_t Offset = RelI->getOffset();
1281 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset
1283 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be) &&
1284 (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26)) {
1285 // This is an AArch64 branch relocation, need to use a stub function.
1286 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
1287 SectionEntry &Section = Sections[SectionID];
1289 // Look for an existing stub.
1290 StubMap::const_iterator i = Stubs.find(Value);
1291 if (i != Stubs.end()) {
1292 resolveRelocation(Section, Offset,
1293 (uint64_t)Section.getAddressWithOffset(i->second),
1295 DEBUG(dbgs() << " Stub function found\n");
1297 // Create a new stub function.
1298 DEBUG(dbgs() << " Create a new stub function\n");
1299 Stubs[Value] = Section.getStubOffset();
1300 uint8_t *StubTargetAddr = createStubFunction(
1301 Section.getAddressWithOffset(Section.getStubOffset()));
1303 RelocationEntry REmovz_g3(SectionID,
1304 StubTargetAddr - Section.getAddress(),
1305 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
1306 RelocationEntry REmovk_g2(SectionID, StubTargetAddr -
1307 Section.getAddress() + 4,
1308 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
1309 RelocationEntry REmovk_g1(SectionID, StubTargetAddr -
1310 Section.getAddress() + 8,
1311 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
1312 RelocationEntry REmovk_g0(SectionID, StubTargetAddr -
1313 Section.getAddress() + 12,
1314 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
1316 if (Value.SymbolName) {
1317 addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1318 addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1319 addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1320 addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1322 addRelocationForSection(REmovz_g3, Value.SectionID);
1323 addRelocationForSection(REmovk_g2, Value.SectionID);
1324 addRelocationForSection(REmovk_g1, Value.SectionID);
1325 addRelocationForSection(REmovk_g0, Value.SectionID);
1327 resolveRelocation(Section, Offset,
1328 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(
1329 Section.getStubOffset())),
1331 Section.advanceStubOffset(getMaxStubSize());
1333 } else if (Arch == Triple::arm) {
1334 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL ||
1335 RelType == ELF::R_ARM_JUMP24) {
1336 // This is an ARM branch relocation, need to use a stub function.
1337 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.\n");
1338 SectionEntry &Section = Sections[SectionID];
1340 // Look for an existing stub.
1341 StubMap::const_iterator i = Stubs.find(Value);
1342 if (i != Stubs.end()) {
1345 reinterpret_cast<uint64_t>(Section.getAddressWithOffset(i->second)),
1347 DEBUG(dbgs() << " Stub function found\n");
1349 // Create a new stub function.
1350 DEBUG(dbgs() << " Create a new stub function\n");
1351 Stubs[Value] = Section.getStubOffset();
1352 uint8_t *StubTargetAddr = createStubFunction(
1353 Section.getAddressWithOffset(Section.getStubOffset()));
1354 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1355 ELF::R_ARM_ABS32, Value.Addend);
1356 if (Value.SymbolName)
1357 addRelocationForSymbol(RE, Value.SymbolName);
1359 addRelocationForSection(RE, Value.SectionID);
1361 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1362 Section.getAddressWithOffset(
1363 Section.getStubOffset())),
1365 Section.advanceStubOffset(getMaxStubSize());
1368 uint32_t *Placeholder =
1369 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset));
1370 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 ||
1371 RelType == ELF::R_ARM_ABS32) {
1372 Value.Addend += *Placeholder;
1373 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) {
1374 // See ELF for ARM documentation
1375 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12));
1377 processSimpleRelocation(SectionID, Offset, RelType, Value);
1379 } else if (IsMipsO32ABI) {
1380 uint8_t *Placeholder = reinterpret_cast<uint8_t *>(
1381 computePlaceholderAddress(SectionID, Offset));
1382 uint32_t Opcode = readBytesUnaligned(Placeholder, 4);
1383 if (RelType == ELF::R_MIPS_26) {
1384 // This is an Mips branch relocation, need to use a stub function.
1385 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1386 SectionEntry &Section = Sections[SectionID];
1388 // Extract the addend from the instruction.
1389 // We shift up by two since the Value will be down shifted again
1390 // when applying the relocation.
1391 uint32_t Addend = (Opcode & 0x03ffffff) << 2;
1393 Value.Addend += Addend;
1395 // Look up for existing stub.
1396 StubMap::const_iterator i = Stubs.find(Value);
1397 if (i != Stubs.end()) {
1398 RelocationEntry RE(SectionID, Offset, RelType, i->second);
1399 addRelocationForSection(RE, SectionID);
1400 DEBUG(dbgs() << " Stub function found\n");
1402 // Create a new stub function.
1403 DEBUG(dbgs() << " Create a new stub function\n");
1404 Stubs[Value] = Section.getStubOffset();
1406 unsigned AbiVariant;
1407 O.getPlatformFlags(AbiVariant);
1409 uint8_t *StubTargetAddr = createStubFunction(
1410 Section.getAddressWithOffset(Section.getStubOffset()), AbiVariant);
1412 // Creating Hi and Lo relocations for the filled stub instructions.
1413 RelocationEntry REHi(SectionID, StubTargetAddr - Section.getAddress(),
1414 ELF::R_MIPS_HI16, Value.Addend);
1415 RelocationEntry RELo(SectionID,
1416 StubTargetAddr - Section.getAddress() + 4,
1417 ELF::R_MIPS_LO16, Value.Addend);
1419 if (Value.SymbolName) {
1420 addRelocationForSymbol(REHi, Value.SymbolName);
1421 addRelocationForSymbol(RELo, Value.SymbolName);
1424 addRelocationForSection(REHi, Value.SectionID);
1425 addRelocationForSection(RELo, Value.SectionID);
1428 RelocationEntry RE(SectionID, Offset, RelType, Section.getStubOffset());
1429 addRelocationForSection(RE, SectionID);
1430 Section.advanceStubOffset(getMaxStubSize());
1432 } else if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16) {
1433 int64_t Addend = (Opcode & 0x0000ffff) << 16;
1434 RelocationEntry RE(SectionID, Offset, RelType, Addend);
1435 PendingRelocs.push_back(std::make_pair(Value, RE));
1436 } else if (RelType == ELF::R_MIPS_LO16 || RelType == ELF::R_MIPS_PCLO16) {
1437 int64_t Addend = Value.Addend + SignExtend32<16>(Opcode & 0x0000ffff);
1438 for (auto I = PendingRelocs.begin(); I != PendingRelocs.end();) {
1439 const RelocationValueRef &MatchingValue = I->first;
1440 RelocationEntry &Reloc = I->second;
1441 if (MatchingValue == Value &&
1442 RelType == getMatchingLoRelocation(Reloc.RelType) &&
1443 SectionID == Reloc.SectionID) {
1444 Reloc.Addend += Addend;
1445 if (Value.SymbolName)
1446 addRelocationForSymbol(Reloc, Value.SymbolName);
1448 addRelocationForSection(Reloc, Value.SectionID);
1449 I = PendingRelocs.erase(I);
1453 RelocationEntry RE(SectionID, Offset, RelType, Addend);
1454 if (Value.SymbolName)
1455 addRelocationForSymbol(RE, Value.SymbolName);
1457 addRelocationForSection(RE, Value.SectionID);
1459 if (RelType == ELF::R_MIPS_32)
1460 Value.Addend += Opcode;
1461 else if (RelType == ELF::R_MIPS_PC16)
1462 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2);
1463 else if (RelType == ELF::R_MIPS_PC19_S2)
1464 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2);
1465 else if (RelType == ELF::R_MIPS_PC21_S2)
1466 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2);
1467 else if (RelType == ELF::R_MIPS_PC26_S2)
1468 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2);
1469 processSimpleRelocation(SectionID, Offset, RelType, Value);
1471 } else if (IsMipsN64ABI) {
1472 uint32_t r_type = RelType & 0xff;
1473 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1474 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE
1475 || r_type == ELF::R_MIPS_GOT_DISP) {
1476 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName);
1477 if (i != GOTSymbolOffsets.end())
1478 RE.SymOffset = i->second;
1480 RE.SymOffset = allocateGOTEntries(SectionID, 1);
1481 GOTSymbolOffsets[TargetName] = RE.SymOffset;
1484 if (Value.SymbolName)
1485 addRelocationForSymbol(RE, Value.SymbolName);
1487 addRelocationForSection(RE, Value.SectionID);
1488 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1489 if (RelType == ELF::R_PPC64_REL24) {
1490 // Determine ABI variant in use for this object.
1491 unsigned AbiVariant;
1492 Obj.getPlatformFlags(AbiVariant);
1493 AbiVariant &= ELF::EF_PPC64_ABI;
1494 // A PPC branch relocation will need a stub function if the target is
1495 // an external symbol (Symbol::ST_Unknown) or if the target address
1496 // is not within the signed 24-bits branch address.
1497 SectionEntry &Section = Sections[SectionID];
1498 uint8_t *Target = Section.getAddressWithOffset(Offset);
1499 bool RangeOverflow = false;
1500 if (SymType != SymbolRef::ST_Unknown) {
1501 if (AbiVariant != 2) {
1502 // In the ELFv1 ABI, a function call may point to the .opd entry,
1503 // so the final symbol value is calculated based on the relocation
1504 // values in the .opd section.
1505 if (auto Err = findOPDEntrySection(Obj, ObjSectionToID, Value))
1506 return std::move(Err);
1508 // In the ELFv2 ABI, a function symbol may provide a local entry
1509 // point, which must be used for direct calls.
1510 uint8_t SymOther = Symbol->getOther();
1511 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther);
1513 uint8_t *RelocTarget =
1514 Sections[Value.SectionID].getAddressWithOffset(Value.Addend);
1515 int32_t delta = static_cast<int32_t>(Target - RelocTarget);
1516 // If it is within 26-bits branch range, just set the branch target
1517 if (SignExtend32<26>(delta) == delta) {
1518 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1519 if (Value.SymbolName)
1520 addRelocationForSymbol(RE, Value.SymbolName);
1522 addRelocationForSection(RE, Value.SectionID);
1524 RangeOverflow = true;
1527 if (SymType == SymbolRef::ST_Unknown || RangeOverflow) {
1528 // It is an external symbol (SymbolRef::ST_Unknown) or within a range
1529 // larger than 24-bits.
1530 StubMap::const_iterator i = Stubs.find(Value);
1531 if (i != Stubs.end()) {
1532 // Symbol function stub already created, just relocate to it
1533 resolveRelocation(Section, Offset,
1534 reinterpret_cast<uint64_t>(
1535 Section.getAddressWithOffset(i->second)),
1537 DEBUG(dbgs() << " Stub function found\n");
1539 // Create a new stub function.
1540 DEBUG(dbgs() << " Create a new stub function\n");
1541 Stubs[Value] = Section.getStubOffset();
1542 uint8_t *StubTargetAddr = createStubFunction(
1543 Section.getAddressWithOffset(Section.getStubOffset()),
1545 RelocationEntry RE(SectionID, StubTargetAddr - Section.getAddress(),
1546 ELF::R_PPC64_ADDR64, Value.Addend);
1548 // Generates the 64-bits address loads as exemplified in section
1549 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to
1550 // apply to the low part of the instructions, so we have to update
1551 // the offset according to the target endianness.
1552 uint64_t StubRelocOffset = StubTargetAddr - Section.getAddress();
1553 if (!IsTargetLittleEndian)
1554 StubRelocOffset += 2;
1556 RelocationEntry REhst(SectionID, StubRelocOffset + 0,
1557 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1558 RelocationEntry REhr(SectionID, StubRelocOffset + 4,
1559 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1560 RelocationEntry REh(SectionID, StubRelocOffset + 12,
1561 ELF::R_PPC64_ADDR16_HI, Value.Addend);
1562 RelocationEntry REl(SectionID, StubRelocOffset + 16,
1563 ELF::R_PPC64_ADDR16_LO, Value.Addend);
1565 if (Value.SymbolName) {
1566 addRelocationForSymbol(REhst, Value.SymbolName);
1567 addRelocationForSymbol(REhr, Value.SymbolName);
1568 addRelocationForSymbol(REh, Value.SymbolName);
1569 addRelocationForSymbol(REl, Value.SymbolName);
1571 addRelocationForSection(REhst, Value.SectionID);
1572 addRelocationForSection(REhr, Value.SectionID);
1573 addRelocationForSection(REh, Value.SectionID);
1574 addRelocationForSection(REl, Value.SectionID);
1577 resolveRelocation(Section, Offset, reinterpret_cast<uint64_t>(
1578 Section.getAddressWithOffset(
1579 Section.getStubOffset())),
1581 Section.advanceStubOffset(getMaxStubSize());
1583 if (SymType == SymbolRef::ST_Unknown) {
1584 // Restore the TOC for external calls
1585 if (AbiVariant == 2)
1586 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1)
1588 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1)
1591 } else if (RelType == ELF::R_PPC64_TOC16 ||
1592 RelType == ELF::R_PPC64_TOC16_DS ||
1593 RelType == ELF::R_PPC64_TOC16_LO ||
1594 RelType == ELF::R_PPC64_TOC16_LO_DS ||
1595 RelType == ELF::R_PPC64_TOC16_HI ||
1596 RelType == ELF::R_PPC64_TOC16_HA) {
1597 // These relocations are supposed to subtract the TOC address from
1598 // the final value. This does not fit cleanly into the RuntimeDyld
1599 // scheme, since there may be *two* sections involved in determining
1600 // the relocation value (the section of the symbol referred to by the
1601 // relocation, and the TOC section associated with the current module).
1603 // Fortunately, these relocations are currently only ever generated
1604 // referring to symbols that themselves reside in the TOC, which means
1605 // that the two sections are actually the same. Thus they cancel out
1606 // and we can immediately resolve the relocation right now.
1608 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break;
1609 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break;
1610 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break;
1611 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break;
1612 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break;
1613 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break;
1614 default: llvm_unreachable("Wrong relocation type.");
1617 RelocationValueRef TOCValue;
1618 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, TOCValue))
1619 return std::move(Err);
1620 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID)
1621 llvm_unreachable("Unsupported TOC relocation.");
1622 Value.Addend -= TOCValue.Addend;
1623 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0);
1625 // There are two ways to refer to the TOC address directly: either
1626 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are
1627 // ignored), or via any relocation that refers to the magic ".TOC."
1628 // symbols (in which case the addend is respected).
1629 if (RelType == ELF::R_PPC64_TOC) {
1630 RelType = ELF::R_PPC64_ADDR64;
1631 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1632 return std::move(Err);
1633 } else if (TargetName == ".TOC.") {
1634 if (auto Err = findPPC64TOCSection(Obj, ObjSectionToID, Value))
1635 return std::move(Err);
1636 Value.Addend += Addend;
1639 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1641 if (Value.SymbolName)
1642 addRelocationForSymbol(RE, Value.SymbolName);
1644 addRelocationForSection(RE, Value.SectionID);
1646 } else if (Arch == Triple::systemz &&
1647 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) {
1648 // Create function stubs for both PLT and GOT references, regardless of
1649 // whether the GOT reference is to data or code. The stub contains the
1650 // full address of the symbol, as needed by GOT references, and the
1651 // executable part only adds an overhead of 8 bytes.
1653 // We could try to conserve space by allocating the code and data
1654 // parts of the stub separately. However, as things stand, we allocate
1655 // a stub for every relocation, so using a GOT in JIT code should be
1656 // no less space efficient than using an explicit constant pool.
1657 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1658 SectionEntry &Section = Sections[SectionID];
1660 // Look for an existing stub.
1661 StubMap::const_iterator i = Stubs.find(Value);
1662 uintptr_t StubAddress;
1663 if (i != Stubs.end()) {
1664 StubAddress = uintptr_t(Section.getAddressWithOffset(i->second));
1665 DEBUG(dbgs() << " Stub function found\n");
1667 // Create a new stub function.
1668 DEBUG(dbgs() << " Create a new stub function\n");
1670 uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1671 uintptr_t StubAlignment = getStubAlignment();
1673 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1675 unsigned StubOffset = StubAddress - BaseAddress;
1677 Stubs[Value] = StubOffset;
1678 createStubFunction((uint8_t *)StubAddress);
1679 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
1681 if (Value.SymbolName)
1682 addRelocationForSymbol(RE, Value.SymbolName);
1684 addRelocationForSection(RE, Value.SectionID);
1685 Section.advanceStubOffset(getMaxStubSize());
1688 if (RelType == ELF::R_390_GOTENT)
1689 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL,
1692 resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1693 } else if (Arch == Triple::x86_64) {
1694 if (RelType == ELF::R_X86_64_PLT32) {
1695 // The way the PLT relocations normally work is that the linker allocates
1697 // PLT and this relocation makes a PC-relative call into the PLT. The PLT
1698 // entry will then jump to an address provided by the GOT. On first call,
1700 // GOT address will point back into PLT code that resolves the symbol. After
1701 // the first call, the GOT entry points to the actual function.
1703 // For local functions we're ignoring all of that here and just replacing
1704 // the PLT32 relocation type with PC32, which will translate the relocation
1705 // into a PC-relative call directly to the function. For external symbols we
1706 // can't be sure the function will be within 2^32 bytes of the call site, so
1707 // we need to create a stub, which calls into the GOT. This case is
1708 // equivalent to the usual PLT implementation except that we use the stub
1709 // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1710 // rather than allocating a PLT section.
1711 if (Value.SymbolName) {
1712 // This is a call to an external function.
1713 // Look for an existing stub.
1714 SectionEntry &Section = Sections[SectionID];
1715 StubMap::const_iterator i = Stubs.find(Value);
1716 uintptr_t StubAddress;
1717 if (i != Stubs.end()) {
1718 StubAddress = uintptr_t(Section.getAddress()) + i->second;
1719 DEBUG(dbgs() << " Stub function found\n");
1721 // Create a new stub function (equivalent to a PLT entry).
1722 DEBUG(dbgs() << " Create a new stub function\n");
1724 uintptr_t BaseAddress = uintptr_t(Section.getAddress());
1725 uintptr_t StubAlignment = getStubAlignment();
1727 (BaseAddress + Section.getStubOffset() + StubAlignment - 1) &
1729 unsigned StubOffset = StubAddress - BaseAddress;
1730 Stubs[Value] = StubOffset;
1731 createStubFunction((uint8_t *)StubAddress);
1733 // Bump our stub offset counter
1734 Section.advanceStubOffset(getMaxStubSize());
1736 // Allocate a GOT Entry
1737 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1);
1739 // The load of the GOT address has an addend of -4
1740 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4);
1742 // Fill in the value of the symbol we're targeting into the GOT
1743 addRelocationForSymbol(
1744 computeGOTOffsetRE(SectionID, GOTOffset, 0, ELF::R_X86_64_64),
1748 // Make the target call a call into the stub table.
1749 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32,
1752 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1754 addRelocationForSection(RE, Value.SectionID);
1756 } else if (RelType == ELF::R_X86_64_GOTPCREL ||
1757 RelType == ELF::R_X86_64_GOTPCRELX ||
1758 RelType == ELF::R_X86_64_REX_GOTPCRELX) {
1759 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1);
1760 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend);
1762 // Fill in the value of the symbol we're targeting into the GOT
1763 RelocationEntry RE = computeGOTOffsetRE(SectionID, GOTOffset, Value.Offset, ELF::R_X86_64_64);
1764 if (Value.SymbolName)
1765 addRelocationForSymbol(RE, Value.SymbolName);
1767 addRelocationForSection(RE, Value.SectionID);
1768 } else if (RelType == ELF::R_X86_64_PC32) {
1769 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1770 processSimpleRelocation(SectionID, Offset, RelType, Value);
1771 } else if (RelType == ELF::R_X86_64_PC64) {
1772 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset));
1773 processSimpleRelocation(SectionID, Offset, RelType, Value);
1775 processSimpleRelocation(SectionID, Offset, RelType, Value);
1778 if (Arch == Triple::x86) {
1779 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1781 processSimpleRelocation(SectionID, Offset, RelType, Value);
1786 size_t RuntimeDyldELF::getGOTEntrySize() {
1787 // We don't use the GOT in all of these cases, but it's essentially free
1788 // to put them all here.
1791 case Triple::x86_64:
1792 case Triple::aarch64:
1793 case Triple::aarch64_be:
1795 case Triple::ppc64le:
1796 case Triple::systemz:
1797 Result = sizeof(uint64_t);
1802 Result = sizeof(uint32_t);
1805 case Triple::mipsel:
1806 case Triple::mips64:
1807 case Triple::mips64el:
1809 Result = sizeof(uint32_t);
1810 else if (IsMipsN64ABI)
1811 Result = sizeof(uint64_t);
1813 llvm_unreachable("Mips ABI not handled");
1816 llvm_unreachable("Unsupported CPU type!");
1821 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned SectionID, unsigned no)
1823 (void)SectionID; // The GOT Section is the same for all section in the object file
1824 if (GOTSectionID == 0) {
1825 GOTSectionID = Sections.size();
1826 // Reserve a section id. We'll allocate the section later
1827 // once we know the total size
1828 Sections.push_back(SectionEntry(".got", nullptr, 0, 0, 0));
1830 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize();
1831 CurrentGOTIndex += no;
1835 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset, uint64_t GOTOffset)
1837 // Fill in the relative address of the GOT Entry into the stub
1838 RelocationEntry GOTRE(SectionID, Offset, ELF::R_X86_64_PC32, GOTOffset);
1839 addRelocationForSection(GOTRE, GOTSectionID);
1842 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(unsigned SectionID, uint64_t GOTOffset, uint64_t SymbolOffset,
1845 (void)SectionID; // The GOT Section is the same for all section in the object file
1846 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset);
1849 Error RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj,
1850 ObjSectionToIDMap &SectionMap) {
1852 if (!PendingRelocs.empty())
1853 return make_error<RuntimeDyldError>("Can't find matching LO16 reloc");
1855 // If necessary, allocate the global offset table
1856 if (GOTSectionID != 0) {
1857 // Allocate memory for the section
1858 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize();
1859 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(),
1860 GOTSectionID, ".got", false);
1862 return make_error<RuntimeDyldError>("Unable to allocate memory for GOT!");
1864 Sections[GOTSectionID] =
1865 SectionEntry(".got", Addr, TotalSize, TotalSize, 0);
1868 Checker->registerSection(Obj.getFileName(), GOTSectionID);
1870 // For now, initialize all GOT entries to zero. We'll fill them in as
1871 // needed when GOT-based relocations are applied.
1872 memset(Addr, 0, TotalSize);
1874 // To correctly resolve Mips GOT relocations, we need a mapping from
1875 // object's sections to GOTs.
1876 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
1878 if (SI->relocation_begin() != SI->relocation_end()) {
1879 section_iterator RelocatedSection = SI->getRelocatedSection();
1880 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection);
1881 assert (i != SectionMap.end());
1882 SectionToGOTMap[i->second] = GOTSectionID;
1885 GOTSymbolOffsets.clear();
1889 // Look for and record the EH frame section.
1890 ObjSectionToIDMap::iterator i, e;
1891 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1892 const SectionRef &Section = i->first;
1894 Section.getName(Name);
1895 if (Name == ".eh_frame") {
1896 UnregisteredEHFrameSections.push_back(i->second);
1902 CurrentGOTIndex = 0;
1904 return Error::success();
1907 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const {
1911 bool RuntimeDyldELF::relocationNeedsStub(const RelocationRef &R) const {
1912 if (Arch != Triple::x86_64)
1913 return true; // Conservative answer
1915 switch (R.getType()) {
1917 return true; // Conservative answer
1920 case ELF::R_X86_64_GOTPCREL:
1921 case ELF::R_X86_64_GOTPCRELX:
1922 case ELF::R_X86_64_REX_GOTPCRELX:
1923 case ELF::R_X86_64_PC32:
1924 case ELF::R_X86_64_PC64:
1925 case ELF::R_X86_64_64:
1926 // We know that these reloation types won't need a stub function. This list
1927 // can be extended as needed.