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"
33 static inline std::error_code check(std::error_code Err) {
35 report_fatal_error(Err.message());
42 template <class ELFT> class DyldELFObject : public ELFObjectFile<ELFT> {
43 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
45 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
46 typedef Elf_Sym_Impl<ELFT> Elf_Sym;
47 typedef Elf_Rel_Impl<ELFT, false> Elf_Rel;
48 typedef Elf_Rel_Impl<ELFT, true> Elf_Rela;
50 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
52 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type;
55 DyldELFObject(MemoryBufferRef Wrapper, std::error_code &ec);
57 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
59 void updateSymbolAddress(const SymbolRef &SymRef, uint64_t Addr);
61 // Methods for type inquiry through isa, cast and dyn_cast
62 static inline bool classof(const Binary *v) {
63 return (isa<ELFObjectFile<ELFT>>(v) &&
64 classof(cast<ELFObjectFile<ELFT>>(v)));
66 static inline bool classof(const ELFObjectFile<ELFT> *v) {
67 return v->isDyldType();
74 // The MemoryBuffer passed into this constructor is just a wrapper around the
75 // actual memory. Ultimately, the Binary parent class will take ownership of
76 // this MemoryBuffer object but not the underlying memory.
78 DyldELFObject<ELFT>::DyldELFObject(MemoryBufferRef Wrapper, std::error_code &EC)
79 : ELFObjectFile<ELFT>(Wrapper, EC) {
80 this->isDyldELFObject = true;
84 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
86 DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
88 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
90 // This assumes the address passed in matches the target address bitness
91 // The template-based type cast handles everything else.
92 shdr->sh_addr = static_cast<addr_type>(Addr);
96 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
99 Elf_Sym *sym = const_cast<Elf_Sym *>(
100 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl()));
102 // This assumes the address passed in matches the target address bitness
103 // The template-based type cast handles everything else.
104 sym->st_value = static_cast<addr_type>(Addr);
107 class LoadedELFObjectInfo
108 : public RuntimeDyld::LoadedObjectInfoHelper<LoadedELFObjectInfo> {
110 LoadedELFObjectInfo(RuntimeDyldImpl &RTDyld, ObjSectionToIDMap ObjSecToIDMap)
111 : LoadedObjectInfoHelper(RTDyld, std::move(ObjSecToIDMap)) {}
113 OwningBinary<ObjectFile>
114 getObjectForDebug(const ObjectFile &Obj) const override;
117 template <typename ELFT>
118 std::unique_ptr<DyldELFObject<ELFT>>
119 createRTDyldELFObject(MemoryBufferRef Buffer,
120 const ObjectFile &SourceObject,
121 const LoadedELFObjectInfo &L,
122 std::error_code &ec) {
123 typedef typename ELFFile<ELFT>::Elf_Shdr Elf_Shdr;
124 typedef typename ELFDataTypeTypedefHelper<ELFT>::value_type addr_type;
126 std::unique_ptr<DyldELFObject<ELFT>> Obj =
127 llvm::make_unique<DyldELFObject<ELFT>>(Buffer, ec);
129 // Iterate over all sections in the object.
130 auto SI = SourceObject.section_begin();
131 for (const auto &Sec : Obj->sections()) {
132 StringRef SectionName;
133 Sec.getName(SectionName);
134 if (SectionName != "") {
135 DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
136 Elf_Shdr *shdr = const_cast<Elf_Shdr *>(
137 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
139 if (uint64_t SecLoadAddr = L.getSectionLoadAddress(*SI)) {
140 // This assumes that the address passed in matches the target address
141 // bitness. The template-based type cast handles everything else.
142 shdr->sh_addr = static_cast<addr_type>(SecLoadAddr);
151 OwningBinary<ObjectFile> createELFDebugObject(const ObjectFile &Obj,
152 const LoadedELFObjectInfo &L) {
153 assert(Obj.isELF() && "Not an ELF object file.");
155 std::unique_ptr<MemoryBuffer> Buffer =
156 MemoryBuffer::getMemBufferCopy(Obj.getData(), Obj.getFileName());
160 std::unique_ptr<ObjectFile> DebugObj;
161 if (Obj.getBytesInAddress() == 4 && Obj.isLittleEndian()) {
162 typedef ELFType<support::little, false> ELF32LE;
163 DebugObj = createRTDyldELFObject<ELF32LE>(Buffer->getMemBufferRef(), Obj, L,
165 } else if (Obj.getBytesInAddress() == 4 && !Obj.isLittleEndian()) {
166 typedef ELFType<support::big, false> ELF32BE;
167 DebugObj = createRTDyldELFObject<ELF32BE>(Buffer->getMemBufferRef(), Obj, L,
169 } else if (Obj.getBytesInAddress() == 8 && !Obj.isLittleEndian()) {
170 typedef ELFType<support::big, true> ELF64BE;
171 DebugObj = createRTDyldELFObject<ELF64BE>(Buffer->getMemBufferRef(), Obj, L,
173 } else if (Obj.getBytesInAddress() == 8 && Obj.isLittleEndian()) {
174 typedef ELFType<support::little, true> ELF64LE;
175 DebugObj = createRTDyldELFObject<ELF64LE>(Buffer->getMemBufferRef(), Obj, L,
178 llvm_unreachable("Unexpected ELF format");
180 assert(!ec && "Could not construct copy ELF object file");
182 return OwningBinary<ObjectFile>(std::move(DebugObj), std::move(Buffer));
185 OwningBinary<ObjectFile>
186 LoadedELFObjectInfo::getObjectForDebug(const ObjectFile &Obj) const {
187 return createELFDebugObject(Obj, *this);
194 RuntimeDyldELF::RuntimeDyldELF(RuntimeDyld::MemoryManager &MemMgr,
195 RuntimeDyld::SymbolResolver &Resolver)
196 : RuntimeDyldImpl(MemMgr, Resolver), GOTSectionID(0), CurrentGOTIndex(0) {}
197 RuntimeDyldELF::~RuntimeDyldELF() {}
199 void RuntimeDyldELF::registerEHFrames() {
200 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
201 SID EHFrameSID = UnregisteredEHFrameSections[i];
202 uint8_t *EHFrameAddr = Sections[EHFrameSID].Address;
203 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress;
204 size_t EHFrameSize = Sections[EHFrameSID].Size;
205 MemMgr.registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
206 RegisteredEHFrameSections.push_back(EHFrameSID);
208 UnregisteredEHFrameSections.clear();
211 void RuntimeDyldELF::deregisterEHFrames() {
212 for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) {
213 SID EHFrameSID = RegisteredEHFrameSections[i];
214 uint8_t *EHFrameAddr = Sections[EHFrameSID].Address;
215 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress;
216 size_t EHFrameSize = Sections[EHFrameSID].Size;
217 MemMgr.deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
219 RegisteredEHFrameSections.clear();
222 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
223 RuntimeDyldELF::loadObject(const object::ObjectFile &O) {
224 return llvm::make_unique<LoadedELFObjectInfo>(*this, loadObjectImpl(O));
227 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
228 uint64_t Offset, uint64_t Value,
229 uint32_t Type, int64_t Addend,
230 uint64_t SymOffset) {
233 llvm_unreachable("Relocation type not implemented yet!");
235 case ELF::R_X86_64_64: {
236 support::ulittle64_t::ref(Section.Address + Offset) = Value + Addend;
237 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
238 << format("%p\n", Section.Address + 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.Address + Offset) = TruncatedAddr;
249 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at "
250 << format("%p\n", Section.Address + Offset));
253 case ELF::R_X86_64_PC32: {
254 uint64_t FinalAddress = Section.LoadAddress + Offset;
255 int64_t RealOffset = Value + Addend - FinalAddress;
256 assert(isInt<32>(RealOffset));
257 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
258 support::ulittle32_t::ref(Section.Address + Offset) = TruncOffset;
261 case ELF::R_X86_64_PC64: {
262 uint64_t FinalAddress = Section.LoadAddress + Offset;
263 int64_t RealOffset = Value + Addend - FinalAddress;
264 support::ulittle64_t::ref(Section.Address + Offset) = RealOffset;
270 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
271 uint64_t Offset, uint32_t Value,
272 uint32_t Type, int32_t Addend) {
274 case ELF::R_386_32: {
275 support::ulittle32_t::ref(Section.Address + Offset) = Value + Addend;
278 case ELF::R_386_PC32: {
279 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
280 uint32_t RealOffset = Value + Addend - FinalAddress;
281 support::ulittle32_t::ref(Section.Address + Offset) = RealOffset;
285 // There are other relocation types, but it appears these are the
286 // only ones currently used by the LLVM ELF object writer
287 llvm_unreachable("Relocation type not implemented yet!");
292 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
293 uint64_t Offset, uint64_t Value,
294 uint32_t Type, int64_t Addend) {
295 uint32_t *TargetPtr = reinterpret_cast<uint32_t *>(Section.Address + Offset);
296 uint64_t FinalAddress = Section.LoadAddress + Offset;
298 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
299 << format("%llx", Section.Address + Offset)
300 << " FinalAddress: 0x" << format("%llx", FinalAddress)
301 << " Value: 0x" << format("%llx", Value) << " Type: 0x"
302 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend)
307 llvm_unreachable("Relocation type not implemented yet!");
309 case ELF::R_AARCH64_ABS64: {
310 uint64_t *TargetPtr =
311 reinterpret_cast<uint64_t *>(Section.Address + Offset);
312 *TargetPtr = Value + Addend;
315 case ELF::R_AARCH64_PREL32: {
316 uint64_t Result = Value + Addend - FinalAddress;
317 assert(static_cast<int64_t>(Result) >= INT32_MIN &&
318 static_cast<int64_t>(Result) <= UINT32_MAX);
319 *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU);
322 case ELF::R_AARCH64_CALL26: // fallthrough
323 case ELF::R_AARCH64_JUMP26: {
324 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
326 uint64_t BranchImm = Value + Addend - FinalAddress;
328 // "Check that -2^27 <= result < 2^27".
329 assert(isInt<28>(BranchImm));
331 // AArch64 code is emitted with .rela relocations. The data already in any
332 // bits affected by the relocation on entry is garbage.
333 *TargetPtr &= 0xfc000000U;
334 // Immediate goes in bits 25:0 of B and BL.
335 *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2;
338 case ELF::R_AARCH64_MOVW_UABS_G3: {
339 uint64_t Result = Value + Addend;
341 // AArch64 code is emitted with .rela relocations. The data already in any
342 // bits affected by the relocation on entry is garbage.
343 *TargetPtr &= 0xffe0001fU;
344 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
345 *TargetPtr |= Result >> (48 - 5);
346 // Shift must be "lsl #48", in bits 22:21
347 assert((*TargetPtr >> 21 & 0x3) == 3 && "invalid shift for relocation");
350 case ELF::R_AARCH64_MOVW_UABS_G2_NC: {
351 uint64_t Result = Value + Addend;
353 // AArch64 code is emitted with .rela relocations. The data already in any
354 // bits affected by the relocation on entry is garbage.
355 *TargetPtr &= 0xffe0001fU;
356 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
357 *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5));
358 // Shift must be "lsl #32", in bits 22:21
359 assert((*TargetPtr >> 21 & 0x3) == 2 && "invalid shift for relocation");
362 case ELF::R_AARCH64_MOVW_UABS_G1_NC: {
363 uint64_t Result = Value + Addend;
365 // AArch64 code is emitted with .rela relocations. The data already in any
366 // bits affected by the relocation on entry is garbage.
367 *TargetPtr &= 0xffe0001fU;
368 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
369 *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5));
370 // Shift must be "lsl #16", in bits 22:2
371 assert((*TargetPtr >> 21 & 0x3) == 1 && "invalid shift for relocation");
374 case ELF::R_AARCH64_MOVW_UABS_G0_NC: {
375 uint64_t Result = Value + Addend;
377 // AArch64 code is emitted with .rela relocations. The data already in any
378 // bits affected by the relocation on entry is garbage.
379 *TargetPtr &= 0xffe0001fU;
380 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
381 *TargetPtr |= ((Result & 0xffffU) << 5);
382 // Shift must be "lsl #0", in bits 22:21.
383 assert((*TargetPtr >> 21 & 0x3) == 0 && "invalid shift for relocation");
386 case ELF::R_AARCH64_ADR_PREL_PG_HI21: {
387 // Operation: Page(S+A) - Page(P)
389 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL);
391 // Check that -2^32 <= X < 2^32
392 assert(isInt<33>(Result) && "overflow check failed for relocation");
394 // AArch64 code is emitted with .rela relocations. The data already in any
395 // bits affected by the relocation on entry is garbage.
396 *TargetPtr &= 0x9f00001fU;
397 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken
398 // from bits 32:12 of X.
399 *TargetPtr |= ((Result & 0x3000U) << (29 - 12));
400 *TargetPtr |= ((Result & 0x1ffffc000ULL) >> (14 - 5));
403 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: {
405 uint64_t Result = Value + Addend;
407 // AArch64 code is emitted with .rela relocations. The data already in any
408 // bits affected by the relocation on entry is garbage.
409 *TargetPtr &= 0xffc003ffU;
410 // Immediate goes in bits 21:10 of LD/ST instruction, taken
411 // from bits 11:2 of X
412 *TargetPtr |= ((Result & 0xffc) << (10 - 2));
415 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: {
417 uint64_t Result = Value + Addend;
419 // AArch64 code is emitted with .rela relocations. The data already in any
420 // bits affected by the relocation on entry is garbage.
421 *TargetPtr &= 0xffc003ffU;
422 // Immediate goes in bits 21:10 of LD/ST instruction, taken
423 // from bits 11:3 of X
424 *TargetPtr |= ((Result & 0xff8) << (10 - 3));
430 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
431 uint64_t Offset, uint32_t Value,
432 uint32_t Type, int32_t Addend) {
433 // TODO: Add Thumb relocations.
434 uint32_t *TargetPtr = (uint32_t *)(Section.Address + Offset);
435 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
438 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
439 << Section.Address + Offset
440 << " FinalAddress: " << format("%p", FinalAddress) << " Value: "
441 << format("%x", Value) << " Type: " << format("%x", Type)
442 << " Addend: " << format("%x", Addend) << "\n");
446 llvm_unreachable("Not implemented relocation type!");
448 case ELF::R_ARM_NONE:
450 case ELF::R_ARM_PREL31:
451 case ELF::R_ARM_TARGET1:
452 case ELF::R_ARM_ABS32:
455 // Write first 16 bit of 32 bit value to the mov instruction.
456 // Last 4 bit should be shifted.
457 case ELF::R_ARM_MOVW_ABS_NC:
458 case ELF::R_ARM_MOVT_ABS:
459 if (Type == ELF::R_ARM_MOVW_ABS_NC)
460 Value = Value & 0xFFFF;
461 else if (Type == ELF::R_ARM_MOVT_ABS)
462 Value = (Value >> 16) & 0xFFFF;
463 *TargetPtr &= ~0x000F0FFF;
464 *TargetPtr |= Value & 0xFFF;
465 *TargetPtr |= ((Value >> 12) & 0xF) << 16;
467 // Write 24 bit relative value to the branch instruction.
468 case ELF::R_ARM_PC24: // Fall through.
469 case ELF::R_ARM_CALL: // Fall through.
470 case ELF::R_ARM_JUMP24:
471 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
472 RelValue = (RelValue & 0x03FFFFFC) >> 2;
473 assert((*TargetPtr & 0xFFFFFF) == 0xFFFFFE);
474 *TargetPtr &= 0xFF000000;
475 *TargetPtr |= RelValue;
480 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section,
481 uint64_t Offset, uint32_t Value,
482 uint32_t Type, int32_t Addend) {
483 uint8_t *TargetPtr = Section.Address + Offset;
486 DEBUG(dbgs() << "resolveMIPSRelocation, LocalAddress: "
487 << Section.Address + Offset << " FinalAddress: "
488 << format("%p", Section.LoadAddress + Offset) << " Value: "
489 << format("%x", Value) << " Type: " << format("%x", Type)
490 << " Addend: " << format("%x", Addend) << "\n");
492 uint32_t Insn = readBytesUnaligned(TargetPtr, 4);
496 llvm_unreachable("Not implemented relocation type!");
499 writeBytesUnaligned(Value, TargetPtr, 4);
503 Insn |= (Value & 0x0fffffff) >> 2;
504 writeBytesUnaligned(Insn, TargetPtr, 4);
506 case ELF::R_MIPS_HI16:
507 // Get the higher 16-bits. Also add 1 if bit 15 is 1.
509 Insn |= ((Value + 0x8000) >> 16) & 0xffff;
510 writeBytesUnaligned(Insn, TargetPtr, 4);
512 case ELF::R_MIPS_LO16:
514 Insn |= Value & 0xffff;
515 writeBytesUnaligned(Insn, TargetPtr, 4);
517 case ELF::R_MIPS_PC32: {
518 uint32_t FinalAddress = (Section.LoadAddress + Offset);
519 writeBytesUnaligned(Value - FinalAddress, (uint8_t *)TargetPtr, 4);
522 case ELF::R_MIPS_PC16: {
523 uint32_t FinalAddress = (Section.LoadAddress + Offset);
525 Insn |= ((Value - FinalAddress) >> 2) & 0xffff;
526 writeBytesUnaligned(Insn, TargetPtr, 4);
529 case ELF::R_MIPS_PC19_S2: {
530 uint32_t FinalAddress = (Section.LoadAddress + Offset);
532 Insn |= ((Value - (FinalAddress & ~0x3)) >> 2) & 0x7ffff;
533 writeBytesUnaligned(Insn, TargetPtr, 4);
536 case ELF::R_MIPS_PC21_S2: {
537 uint32_t FinalAddress = (Section.LoadAddress + Offset);
539 Insn |= ((Value - FinalAddress) >> 2) & 0x1fffff;
540 writeBytesUnaligned(Insn, TargetPtr, 4);
543 case ELF::R_MIPS_PC26_S2: {
544 uint32_t FinalAddress = (Section.LoadAddress + Offset);
546 Insn |= ((Value - FinalAddress) >> 2) & 0x3ffffff;
547 writeBytesUnaligned(Insn, TargetPtr, 4);
550 case ELF::R_MIPS_PCHI16: {
551 uint32_t FinalAddress = (Section.LoadAddress + Offset);
553 Insn |= ((Value - FinalAddress + 0x8000) >> 16) & 0xffff;
554 writeBytesUnaligned(Insn, TargetPtr, 4);
557 case ELF::R_MIPS_PCLO16: {
558 uint32_t FinalAddress = (Section.LoadAddress + Offset);
560 Insn |= (Value - FinalAddress) & 0xffff;
561 writeBytesUnaligned(Insn, TargetPtr, 4);
567 void RuntimeDyldELF::setMipsABI(const ObjectFile &Obj) {
568 if (Arch == Triple::UnknownArch ||
569 !StringRef(Triple::getArchTypePrefix(Arch)).equals("mips")) {
570 IsMipsO32ABI = false;
571 IsMipsN64ABI = false;
575 Obj.getPlatformFlags(AbiVariant);
576 IsMipsO32ABI = AbiVariant & ELF::EF_MIPS_ABI_O32;
577 IsMipsN64ABI = Obj.getFileFormatName().equals("ELF64-mips");
578 if (AbiVariant & ELF::EF_MIPS_ABI2)
579 llvm_unreachable("Mips N32 ABI is not supported yet");
582 void RuntimeDyldELF::resolveMIPS64Relocation(const SectionEntry &Section,
583 uint64_t Offset, uint64_t Value,
584 uint32_t Type, int64_t Addend,
587 uint32_t r_type = Type & 0xff;
588 uint32_t r_type2 = (Type >> 8) & 0xff;
589 uint32_t r_type3 = (Type >> 16) & 0xff;
591 // RelType is used to keep information for which relocation type we are
592 // applying relocation.
593 uint32_t RelType = r_type;
594 int64_t CalculatedValue = evaluateMIPS64Relocation(Section, Offset, Value,
596 SymOffset, SectionID);
597 if (r_type2 != ELF::R_MIPS_NONE) {
599 CalculatedValue = evaluateMIPS64Relocation(Section, Offset, 0, RelType,
600 CalculatedValue, SymOffset,
603 if (r_type3 != ELF::R_MIPS_NONE) {
605 CalculatedValue = evaluateMIPS64Relocation(Section, Offset, 0, RelType,
606 CalculatedValue, SymOffset,
609 applyMIPS64Relocation(Section.Address + Offset, CalculatedValue, RelType);
613 RuntimeDyldELF::evaluateMIPS64Relocation(const SectionEntry &Section,
614 uint64_t Offset, uint64_t Value,
615 uint32_t Type, int64_t Addend,
616 uint64_t SymOffset, SID SectionID) {
618 DEBUG(dbgs() << "evaluateMIPS64Relocation, LocalAddress: 0x"
619 << format("%llx", Section.Address + Offset)
620 << " FinalAddress: 0x"
621 << format("%llx", Section.LoadAddress + Offset)
622 << " Value: 0x" << format("%llx", Value) << " Type: 0x"
623 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend)
624 << " SymOffset: " << format("%x", SymOffset)
629 llvm_unreachable("Not implemented relocation type!");
631 case ELF::R_MIPS_JALR:
632 case ELF::R_MIPS_NONE:
636 return Value + Addend;
638 return ((Value + Addend) >> 2) & 0x3ffffff;
639 case ELF::R_MIPS_GPREL16: {
640 uint64_t GOTAddr = getSectionLoadAddress(SectionToGOTMap[SectionID]);
641 return Value + Addend - (GOTAddr + 0x7ff0);
643 case ELF::R_MIPS_SUB:
644 return Value - Addend;
645 case ELF::R_MIPS_HI16:
646 // Get the higher 16-bits. Also add 1 if bit 15 is 1.
647 return ((Value + Addend + 0x8000) >> 16) & 0xffff;
648 case ELF::R_MIPS_LO16:
649 return (Value + Addend) & 0xffff;
650 case ELF::R_MIPS_CALL16:
651 case ELF::R_MIPS_GOT_DISP:
652 case ELF::R_MIPS_GOT_PAGE: {
653 uint8_t *LocalGOTAddr =
654 getSectionAddress(SectionToGOTMap[SectionID]) + SymOffset;
655 uint64_t GOTEntry = readBytesUnaligned(LocalGOTAddr, 8);
658 if (Type == ELF::R_MIPS_GOT_PAGE)
659 Value = (Value + 0x8000) & ~0xffff;
662 assert(GOTEntry == Value &&
663 "GOT entry has two different addresses.");
665 writeBytesUnaligned(Value, LocalGOTAddr, 8);
667 return (SymOffset - 0x7ff0) & 0xffff;
669 case ELF::R_MIPS_GOT_OFST: {
670 int64_t page = (Value + Addend + 0x8000) & ~0xffff;
671 return (Value + Addend - page) & 0xffff;
673 case ELF::R_MIPS_GPREL32: {
674 uint64_t GOTAddr = getSectionLoadAddress(SectionToGOTMap[SectionID]);
675 return Value + Addend - (GOTAddr + 0x7ff0);
677 case ELF::R_MIPS_PC16: {
678 uint64_t FinalAddress = (Section.LoadAddress + Offset);
679 return ((Value + Addend - FinalAddress) >> 2) & 0xffff;
681 case ELF::R_MIPS_PC32: {
682 uint64_t FinalAddress = (Section.LoadAddress + Offset);
683 return Value + Addend - FinalAddress;
685 case ELF::R_MIPS_PC18_S3: {
686 uint64_t FinalAddress = (Section.LoadAddress + Offset);
687 return ((Value + Addend - ((FinalAddress | 7) ^ 7)) >> 3) & 0x3ffff;
689 case ELF::R_MIPS_PC19_S2: {
690 uint64_t FinalAddress = (Section.LoadAddress + Offset);
691 return ((Value + Addend - FinalAddress) >> 2) & 0x7ffff;
693 case ELF::R_MIPS_PC21_S2: {
694 uint64_t FinalAddress = (Section.LoadAddress + Offset);
695 return ((Value + Addend - FinalAddress) >> 2) & 0x1fffff;
697 case ELF::R_MIPS_PC26_S2: {
698 uint64_t FinalAddress = (Section.LoadAddress + Offset);
699 return ((Value + Addend - FinalAddress) >> 2) & 0x3ffffff;
701 case ELF::R_MIPS_PCHI16: {
702 uint64_t FinalAddress = (Section.LoadAddress + Offset);
703 return ((Value + Addend - FinalAddress + 0x8000) >> 16) & 0xffff;
705 case ELF::R_MIPS_PCLO16: {
706 uint64_t FinalAddress = (Section.LoadAddress + Offset);
707 return (Value + Addend - FinalAddress) & 0xffff;
713 void RuntimeDyldELF::applyMIPS64Relocation(uint8_t *TargetPtr,
714 int64_t CalculatedValue,
716 uint32_t Insn = readBytesUnaligned(TargetPtr, 4);
722 case ELF::R_MIPS_GPREL32:
723 case ELF::R_MIPS_PC32:
724 writeBytesUnaligned(CalculatedValue & 0xffffffff, TargetPtr, 4);
727 case ELF::R_MIPS_SUB:
728 writeBytesUnaligned(CalculatedValue, TargetPtr, 8);
731 case ELF::R_MIPS_PC26_S2:
732 Insn = (Insn & 0xfc000000) | CalculatedValue;
733 writeBytesUnaligned(Insn, TargetPtr, 4);
735 case ELF::R_MIPS_GPREL16:
736 Insn = (Insn & 0xffff0000) | (CalculatedValue & 0xffff);
737 writeBytesUnaligned(Insn, TargetPtr, 4);
739 case ELF::R_MIPS_HI16:
740 case ELF::R_MIPS_LO16:
741 case ELF::R_MIPS_PCHI16:
742 case ELF::R_MIPS_PCLO16:
743 case ELF::R_MIPS_PC16:
744 case ELF::R_MIPS_CALL16:
745 case ELF::R_MIPS_GOT_DISP:
746 case ELF::R_MIPS_GOT_PAGE:
747 case ELF::R_MIPS_GOT_OFST:
748 Insn = (Insn & 0xffff0000) | CalculatedValue;
749 writeBytesUnaligned(Insn, TargetPtr, 4);
751 case ELF::R_MIPS_PC18_S3:
752 Insn = (Insn & 0xfffc0000) | CalculatedValue;
753 writeBytesUnaligned(Insn, TargetPtr, 4);
755 case ELF::R_MIPS_PC19_S2:
756 Insn = (Insn & 0xfff80000) | CalculatedValue;
757 writeBytesUnaligned(Insn, TargetPtr, 4);
759 case ELF::R_MIPS_PC21_S2:
760 Insn = (Insn & 0xffe00000) | CalculatedValue;
761 writeBytesUnaligned(Insn, TargetPtr, 4);
766 // Return the .TOC. section and offset.
767 void RuntimeDyldELF::findPPC64TOCSection(const ELFObjectFileBase &Obj,
768 ObjSectionToIDMap &LocalSections,
769 RelocationValueRef &Rel) {
770 // Set a default SectionID in case we do not find a TOC section below.
771 // This may happen for references to TOC base base (sym@toc, .odp
772 // relocation) without a .toc directive. In this case just use the
773 // first section (which is usually the .odp) since the code won't
774 // reference the .toc base directly.
775 Rel.SymbolName = NULL;
778 // The TOC consists of sections .got, .toc, .tocbss, .plt in that
779 // order. The TOC starts where the first of these sections starts.
780 for (auto &Section: Obj.sections()) {
781 StringRef SectionName;
782 check(Section.getName(SectionName));
784 if (SectionName == ".got"
785 || SectionName == ".toc"
786 || SectionName == ".tocbss"
787 || SectionName == ".plt") {
788 Rel.SectionID = findOrEmitSection(Obj, Section, false, LocalSections);
793 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
794 // thus permitting a full 64 Kbytes segment.
798 // Returns the sections and offset associated with the ODP entry referenced
800 void RuntimeDyldELF::findOPDEntrySection(const ELFObjectFileBase &Obj,
801 ObjSectionToIDMap &LocalSections,
802 RelocationValueRef &Rel) {
803 // Get the ELF symbol value (st_value) to compare with Relocation offset in
805 for (section_iterator si = Obj.section_begin(), se = Obj.section_end();
807 section_iterator RelSecI = si->getRelocatedSection();
808 if (RelSecI == Obj.section_end())
811 StringRef RelSectionName;
812 check(RelSecI->getName(RelSectionName));
813 if (RelSectionName != ".opd")
816 for (elf_relocation_iterator i = si->relocation_begin(),
817 e = si->relocation_end();
819 // The R_PPC64_ADDR64 relocation indicates the first field
821 uint64_t TypeFunc = i->getType();
822 if (TypeFunc != ELF::R_PPC64_ADDR64) {
827 uint64_t TargetSymbolOffset = i->getOffset();
828 symbol_iterator TargetSymbol = i->getSymbol();
829 ErrorOr<int64_t> AddendOrErr = i->getAddend();
830 Check(AddendOrErr.getError());
831 int64_t Addend = *AddendOrErr;
837 // Just check if following relocation is a R_PPC64_TOC
838 uint64_t TypeTOC = i->getType();
839 if (TypeTOC != ELF::R_PPC64_TOC)
842 // Finally compares the Symbol value and the target symbol offset
843 // to check if this .opd entry refers to the symbol the relocation
845 if (Rel.Addend != (int64_t)TargetSymbolOffset)
848 section_iterator tsi(Obj.section_end());
849 check(TargetSymbol->getSection(tsi));
850 bool IsCode = tsi->isText();
851 Rel.SectionID = findOrEmitSection(Obj, (*tsi), IsCode, LocalSections);
852 Rel.Addend = (intptr_t)Addend;
856 llvm_unreachable("Attempting to get address of ODP entry!");
859 // Relocation masks following the #lo(value), #hi(value), #ha(value),
860 // #higher(value), #highera(value), #highest(value), and #highesta(value)
861 // macros defined in section 4.5.1. Relocation Types of the PPC-elf64abi
864 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; }
866 static inline uint16_t applyPPChi(uint64_t value) {
867 return (value >> 16) & 0xffff;
870 static inline uint16_t applyPPCha (uint64_t value) {
871 return ((value + 0x8000) >> 16) & 0xffff;
874 static inline uint16_t applyPPChigher(uint64_t value) {
875 return (value >> 32) & 0xffff;
878 static inline uint16_t applyPPChighera (uint64_t value) {
879 return ((value + 0x8000) >> 32) & 0xffff;
882 static inline uint16_t applyPPChighest(uint64_t value) {
883 return (value >> 48) & 0xffff;
886 static inline uint16_t applyPPChighesta (uint64_t value) {
887 return ((value + 0x8000) >> 48) & 0xffff;
890 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
891 uint64_t Offset, uint64_t Value,
892 uint32_t Type, int64_t Addend) {
893 uint8_t *LocalAddress = Section.Address + Offset;
896 llvm_unreachable("Relocation type not implemented yet!");
898 case ELF::R_PPC64_ADDR16:
899 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
901 case ELF::R_PPC64_ADDR16_DS:
902 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
904 case ELF::R_PPC64_ADDR16_LO:
905 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
907 case ELF::R_PPC64_ADDR16_LO_DS:
908 writeInt16BE(LocalAddress, applyPPClo(Value + Addend) & ~3);
910 case ELF::R_PPC64_ADDR16_HI:
911 writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
913 case ELF::R_PPC64_ADDR16_HA:
914 writeInt16BE(LocalAddress, applyPPCha(Value + Addend));
916 case ELF::R_PPC64_ADDR16_HIGHER:
917 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend));
919 case ELF::R_PPC64_ADDR16_HIGHERA:
920 writeInt16BE(LocalAddress, applyPPChighera(Value + Addend));
922 case ELF::R_PPC64_ADDR16_HIGHEST:
923 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend));
925 case ELF::R_PPC64_ADDR16_HIGHESTA:
926 writeInt16BE(LocalAddress, applyPPChighesta(Value + Addend));
928 case ELF::R_PPC64_ADDR14: {
929 assert(((Value + Addend) & 3) == 0);
930 // Preserve the AA/LK bits in the branch instruction
931 uint8_t aalk = *(LocalAddress + 3);
932 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
934 case ELF::R_PPC64_REL16_LO: {
935 uint64_t FinalAddress = (Section.LoadAddress + Offset);
936 uint64_t Delta = Value - FinalAddress + Addend;
937 writeInt16BE(LocalAddress, applyPPClo(Delta));
939 case ELF::R_PPC64_REL16_HI: {
940 uint64_t FinalAddress = (Section.LoadAddress + Offset);
941 uint64_t Delta = Value - FinalAddress + Addend;
942 writeInt16BE(LocalAddress, applyPPChi(Delta));
944 case ELF::R_PPC64_REL16_HA: {
945 uint64_t FinalAddress = (Section.LoadAddress + Offset);
946 uint64_t Delta = Value - FinalAddress + Addend;
947 writeInt16BE(LocalAddress, applyPPCha(Delta));
949 case ELF::R_PPC64_ADDR32: {
950 int32_t Result = static_cast<int32_t>(Value + Addend);
951 if (SignExtend32<32>(Result) != Result)
952 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
953 writeInt32BE(LocalAddress, Result);
955 case ELF::R_PPC64_REL24: {
956 uint64_t FinalAddress = (Section.LoadAddress + Offset);
957 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
958 if (SignExtend32<24>(delta) != delta)
959 llvm_unreachable("Relocation R_PPC64_REL24 overflow");
960 // Generates a 'bl <address>' instruction
961 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
963 case ELF::R_PPC64_REL32: {
964 uint64_t FinalAddress = (Section.LoadAddress + Offset);
965 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
966 if (SignExtend32<32>(delta) != delta)
967 llvm_unreachable("Relocation R_PPC64_REL32 overflow");
968 writeInt32BE(LocalAddress, delta);
970 case ELF::R_PPC64_REL64: {
971 uint64_t FinalAddress = (Section.LoadAddress + Offset);
972 uint64_t Delta = Value - FinalAddress + Addend;
973 writeInt64BE(LocalAddress, Delta);
975 case ELF::R_PPC64_ADDR64:
976 writeInt64BE(LocalAddress, Value + Addend);
981 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
982 uint64_t Offset, uint64_t Value,
983 uint32_t Type, int64_t Addend) {
984 uint8_t *LocalAddress = Section.Address + Offset;
987 llvm_unreachable("Relocation type not implemented yet!");
989 case ELF::R_390_PC16DBL:
990 case ELF::R_390_PLT16DBL: {
991 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
992 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
993 writeInt16BE(LocalAddress, Delta / 2);
996 case ELF::R_390_PC32DBL:
997 case ELF::R_390_PLT32DBL: {
998 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
999 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
1000 writeInt32BE(LocalAddress, Delta / 2);
1003 case ELF::R_390_PC32: {
1004 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
1005 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
1006 writeInt32BE(LocalAddress, Delta);
1010 writeInt64BE(LocalAddress, Value + Addend);
1015 // The target location for the relocation is described by RE.SectionID and
1016 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
1017 // SectionEntry has three members describing its location.
1018 // SectionEntry::Address is the address at which the section has been loaded
1019 // into memory in the current (host) process. SectionEntry::LoadAddress is the
1020 // address that the section will have in the target process.
1021 // SectionEntry::ObjAddress is the address of the bits for this section in the
1022 // original emitted object image (also in the current address space).
1024 // Relocations will be applied as if the section were loaded at
1025 // SectionEntry::LoadAddress, but they will be applied at an address based
1026 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to
1027 // Target memory contents if they are required for value calculations.
1029 // The Value parameter here is the load address of the symbol for the
1030 // relocation to be applied. For relocations which refer to symbols in the
1031 // current object Value will be the LoadAddress of the section in which
1032 // the symbol resides (RE.Addend provides additional information about the
1033 // symbol location). For external symbols, Value will be the address of the
1034 // symbol in the target address space.
1035 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
1037 const SectionEntry &Section = Sections[RE.SectionID];
1038 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
1039 RE.SymOffset, RE.SectionID);
1042 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
1043 uint64_t Offset, uint64_t Value,
1044 uint32_t Type, int64_t Addend,
1045 uint64_t SymOffset, SID SectionID) {
1047 case Triple::x86_64:
1048 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
1051 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
1052 (uint32_t)(Addend & 0xffffffffL));
1054 case Triple::aarch64:
1055 case Triple::aarch64_be:
1056 resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
1058 case Triple::arm: // Fall through.
1061 case Triple::thumbeb:
1062 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
1063 (uint32_t)(Addend & 0xffffffffL));
1065 case Triple::mips: // Fall through.
1066 case Triple::mipsel:
1067 case Triple::mips64:
1068 case Triple::mips64el:
1070 resolveMIPSRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL),
1071 Type, (uint32_t)(Addend & 0xffffffffL));
1072 else if (IsMipsN64ABI)
1073 resolveMIPS64Relocation(Section, Offset, Value, Type, Addend, SymOffset,
1076 llvm_unreachable("Mips ABI not handled");
1078 case Triple::ppc64: // Fall through.
1079 case Triple::ppc64le:
1080 resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
1082 case Triple::systemz:
1083 resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
1086 llvm_unreachable("Unsupported CPU type!");
1090 void *RuntimeDyldELF::computePlaceholderAddress(unsigned SectionID, uint64_t Offset) const {
1091 return (void*)(Sections[SectionID].ObjAddress + Offset);
1094 void RuntimeDyldELF::processSimpleRelocation(unsigned SectionID, uint64_t Offset, unsigned RelType, RelocationValueRef Value) {
1095 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
1096 if (Value.SymbolName)
1097 addRelocationForSymbol(RE, Value.SymbolName);
1099 addRelocationForSection(RE, Value.SectionID);
1102 relocation_iterator RuntimeDyldELF::processRelocationRef(
1103 unsigned SectionID, relocation_iterator RelI, const ObjectFile &O,
1104 ObjSectionToIDMap &ObjSectionToID, StubMap &Stubs) {
1105 const auto &Obj = cast<ELFObjectFileBase>(O);
1106 uint64_t RelType = RelI->getType();
1107 ErrorOr<int64_t> AddendOrErr = ELFRelocationRef(*RelI).getAddend();
1108 int64_t Addend = AddendOrErr ? *AddendOrErr : 0;
1109 elf_symbol_iterator Symbol = RelI->getSymbol();
1111 // Obtain the symbol name which is referenced in the relocation
1112 StringRef TargetName;
1113 if (Symbol != Obj.symbol_end()) {
1114 ErrorOr<StringRef> TargetNameOrErr = Symbol->getName();
1115 if (std::error_code EC = TargetNameOrErr.getError())
1116 report_fatal_error(EC.message());
1117 TargetName = *TargetNameOrErr;
1119 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend
1120 << " TargetName: " << TargetName << "\n");
1121 RelocationValueRef Value;
1122 // First search for the symbol in the local symbol table
1123 SymbolRef::Type SymType = SymbolRef::ST_Unknown;
1125 // Search for the symbol in the global symbol table
1126 RTDyldSymbolTable::const_iterator gsi = GlobalSymbolTable.end();
1127 if (Symbol != Obj.symbol_end()) {
1128 gsi = GlobalSymbolTable.find(TargetName.data());
1129 SymType = Symbol->getType();
1131 if (gsi != GlobalSymbolTable.end()) {
1132 const auto &SymInfo = gsi->second;
1133 Value.SectionID = SymInfo.getSectionID();
1134 Value.Offset = SymInfo.getOffset();
1135 Value.Addend = SymInfo.getOffset() + Addend;
1138 case SymbolRef::ST_Debug: {
1139 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
1140 // and can be changed by another developers. Maybe best way is add
1141 // a new symbol type ST_Section to SymbolRef and use it.
1142 section_iterator si(Obj.section_end());
1143 Symbol->getSection(si);
1144 if (si == Obj.section_end())
1145 llvm_unreachable("Symbol section not found, bad object file format!");
1146 DEBUG(dbgs() << "\t\tThis is section symbol\n");
1147 bool isCode = si->isText();
1148 Value.SectionID = findOrEmitSection(Obj, (*si), isCode, ObjSectionToID);
1149 Value.Addend = Addend;
1152 case SymbolRef::ST_Data:
1153 case SymbolRef::ST_Unknown: {
1154 Value.SymbolName = TargetName.data();
1155 Value.Addend = Addend;
1157 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
1158 // will manifest here as a NULL symbol name.
1159 // We can set this as a valid (but empty) symbol name, and rely
1160 // on addRelocationForSymbol to handle this.
1161 if (!Value.SymbolName)
1162 Value.SymbolName = "";
1166 llvm_unreachable("Unresolved symbol type!");
1171 uint64_t Offset = RelI->getOffset();
1173 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset
1175 if ((Arch == Triple::aarch64 || Arch == Triple::aarch64_be) &&
1176 (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26)) {
1177 // This is an AArch64 branch relocation, need to use a stub function.
1178 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
1179 SectionEntry &Section = Sections[SectionID];
1181 // Look for an existing stub.
1182 StubMap::const_iterator i = Stubs.find(Value);
1183 if (i != Stubs.end()) {
1184 resolveRelocation(Section, Offset, (uint64_t)Section.Address + i->second,
1186 DEBUG(dbgs() << " Stub function found\n");
1188 // Create a new stub function.
1189 DEBUG(dbgs() << " Create a new stub function\n");
1190 Stubs[Value] = Section.StubOffset;
1191 uint8_t *StubTargetAddr =
1192 createStubFunction(Section.Address + Section.StubOffset);
1194 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.Address,
1195 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
1196 RelocationEntry REmovk_g2(SectionID, StubTargetAddr - Section.Address + 4,
1197 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
1198 RelocationEntry REmovk_g1(SectionID, StubTargetAddr - Section.Address + 8,
1199 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
1200 RelocationEntry REmovk_g0(SectionID,
1201 StubTargetAddr - Section.Address + 12,
1202 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
1204 if (Value.SymbolName) {
1205 addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1206 addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1207 addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1208 addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1210 addRelocationForSection(REmovz_g3, Value.SectionID);
1211 addRelocationForSection(REmovk_g2, Value.SectionID);
1212 addRelocationForSection(REmovk_g1, Value.SectionID);
1213 addRelocationForSection(REmovk_g0, Value.SectionID);
1215 resolveRelocation(Section, Offset,
1216 (uint64_t)Section.Address + Section.StubOffset, RelType,
1218 Section.StubOffset += getMaxStubSize();
1220 } else if (Arch == Triple::arm) {
1221 if (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL ||
1222 RelType == ELF::R_ARM_JUMP24) {
1223 // This is an ARM branch relocation, need to use a stub function.
1224 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.");
1225 SectionEntry &Section = Sections[SectionID];
1227 // Look for an existing stub.
1228 StubMap::const_iterator i = Stubs.find(Value);
1229 if (i != Stubs.end()) {
1230 resolveRelocation(Section, Offset, (uint64_t)Section.Address + i->second,
1232 DEBUG(dbgs() << " Stub function found\n");
1234 // Create a new stub function.
1235 DEBUG(dbgs() << " Create a new stub function\n");
1236 Stubs[Value] = Section.StubOffset;
1237 uint8_t *StubTargetAddr =
1238 createStubFunction(Section.Address + Section.StubOffset);
1239 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
1240 ELF::R_ARM_ABS32, Value.Addend);
1241 if (Value.SymbolName)
1242 addRelocationForSymbol(RE, Value.SymbolName);
1244 addRelocationForSection(RE, Value.SectionID);
1246 resolveRelocation(Section, Offset,
1247 (uint64_t)Section.Address + Section.StubOffset, RelType,
1249 Section.StubOffset += getMaxStubSize();
1252 uint32_t *Placeholder =
1253 reinterpret_cast<uint32_t*>(computePlaceholderAddress(SectionID, Offset));
1254 if (RelType == ELF::R_ARM_PREL31 || RelType == ELF::R_ARM_TARGET1 ||
1255 RelType == ELF::R_ARM_ABS32) {
1256 Value.Addend += *Placeholder;
1257 } else if (RelType == ELF::R_ARM_MOVW_ABS_NC || RelType == ELF::R_ARM_MOVT_ABS) {
1258 // See ELF for ARM documentation
1259 Value.Addend += (int16_t)((*Placeholder & 0xFFF) | (((*Placeholder >> 16) & 0xF) << 12));
1261 processSimpleRelocation(SectionID, Offset, RelType, Value);
1263 } else if (IsMipsO32ABI) {
1264 uint8_t *Placeholder = reinterpret_cast<uint8_t *>(
1265 computePlaceholderAddress(SectionID, Offset));
1266 uint32_t Opcode = readBytesUnaligned(Placeholder, 4);
1267 if (RelType == ELF::R_MIPS_26) {
1268 // This is an Mips branch relocation, need to use a stub function.
1269 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1270 SectionEntry &Section = Sections[SectionID];
1272 // Extract the addend from the instruction.
1273 // We shift up by two since the Value will be down shifted again
1274 // when applying the relocation.
1275 uint32_t Addend = (Opcode & 0x03ffffff) << 2;
1277 Value.Addend += Addend;
1279 // Look up for existing stub.
1280 StubMap::const_iterator i = Stubs.find(Value);
1281 if (i != Stubs.end()) {
1282 RelocationEntry RE(SectionID, Offset, RelType, i->second);
1283 addRelocationForSection(RE, SectionID);
1284 DEBUG(dbgs() << " Stub function found\n");
1286 // Create a new stub function.
1287 DEBUG(dbgs() << " Create a new stub function\n");
1288 Stubs[Value] = Section.StubOffset;
1289 uint8_t *StubTargetAddr =
1290 createStubFunction(Section.Address + Section.StubOffset);
1292 // Creating Hi and Lo relocations for the filled stub instructions.
1293 RelocationEntry REHi(SectionID, StubTargetAddr - Section.Address,
1294 ELF::R_MIPS_HI16, Value.Addend);
1295 RelocationEntry RELo(SectionID, StubTargetAddr - Section.Address + 4,
1296 ELF::R_MIPS_LO16, Value.Addend);
1298 if (Value.SymbolName) {
1299 addRelocationForSymbol(REHi, Value.SymbolName);
1300 addRelocationForSymbol(RELo, Value.SymbolName);
1303 addRelocationForSection(REHi, Value.SectionID);
1304 addRelocationForSection(RELo, Value.SectionID);
1307 RelocationEntry RE(SectionID, Offset, RelType, Section.StubOffset);
1308 addRelocationForSection(RE, SectionID);
1309 Section.StubOffset += getMaxStubSize();
1312 // FIXME: Calculate correct addends for R_MIPS_HI16, R_MIPS_LO16,
1313 // R_MIPS_PCHI16 and R_MIPS_PCLO16 relocations.
1314 if (RelType == ELF::R_MIPS_HI16 || RelType == ELF::R_MIPS_PCHI16)
1315 Value.Addend += (Opcode & 0x0000ffff) << 16;
1316 else if (RelType == ELF::R_MIPS_LO16)
1317 Value.Addend += (Opcode & 0x0000ffff);
1318 else if (RelType == ELF::R_MIPS_32)
1319 Value.Addend += Opcode;
1320 else if (RelType == ELF::R_MIPS_PCLO16)
1321 Value.Addend += SignExtend32<16>((Opcode & 0x0000ffff));
1322 else if (RelType == ELF::R_MIPS_PC16)
1323 Value.Addend += SignExtend32<18>((Opcode & 0x0000ffff) << 2);
1324 else if (RelType == ELF::R_MIPS_PC19_S2)
1325 Value.Addend += SignExtend32<21>((Opcode & 0x0007ffff) << 2);
1326 else if (RelType == ELF::R_MIPS_PC21_S2)
1327 Value.Addend += SignExtend32<23>((Opcode & 0x001fffff) << 2);
1328 else if (RelType == ELF::R_MIPS_PC26_S2)
1329 Value.Addend += SignExtend32<28>((Opcode & 0x03ffffff) << 2);
1330 processSimpleRelocation(SectionID, Offset, RelType, Value);
1332 } else if (IsMipsN64ABI) {
1333 uint32_t r_type = RelType & 0xff;
1334 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1335 if (r_type == ELF::R_MIPS_CALL16 || r_type == ELF::R_MIPS_GOT_PAGE
1336 || r_type == ELF::R_MIPS_GOT_DISP) {
1337 StringMap<uint64_t>::iterator i = GOTSymbolOffsets.find(TargetName);
1338 if (i != GOTSymbolOffsets.end())
1339 RE.SymOffset = i->second;
1341 RE.SymOffset = allocateGOTEntries(SectionID, 1);
1342 GOTSymbolOffsets[TargetName] = RE.SymOffset;
1345 if (Value.SymbolName)
1346 addRelocationForSymbol(RE, Value.SymbolName);
1348 addRelocationForSection(RE, Value.SectionID);
1349 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1350 if (RelType == ELF::R_PPC64_REL24) {
1351 // Determine ABI variant in use for this object.
1352 unsigned AbiVariant;
1353 Obj.getPlatformFlags(AbiVariant);
1354 AbiVariant &= ELF::EF_PPC64_ABI;
1355 // A PPC branch relocation will need a stub function if the target is
1356 // an external symbol (Symbol::ST_Unknown) or if the target address
1357 // is not within the signed 24-bits branch address.
1358 SectionEntry &Section = Sections[SectionID];
1359 uint8_t *Target = Section.Address + Offset;
1360 bool RangeOverflow = false;
1361 if (SymType != SymbolRef::ST_Unknown) {
1362 if (AbiVariant != 2) {
1363 // In the ELFv1 ABI, a function call may point to the .opd entry,
1364 // so the final symbol value is calculated based on the relocation
1365 // values in the .opd section.
1366 findOPDEntrySection(Obj, ObjSectionToID, Value);
1368 // In the ELFv2 ABI, a function symbol may provide a local entry
1369 // point, which must be used for direct calls.
1370 uint8_t SymOther = Symbol->getOther();
1371 Value.Addend += ELF::decodePPC64LocalEntryOffset(SymOther);
1373 uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend;
1374 int32_t delta = static_cast<int32_t>(Target - RelocTarget);
1375 // If it is within 24-bits branch range, just set the branch target
1376 if (SignExtend32<24>(delta) == delta) {
1377 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1378 if (Value.SymbolName)
1379 addRelocationForSymbol(RE, Value.SymbolName);
1381 addRelocationForSection(RE, Value.SectionID);
1383 RangeOverflow = true;
1386 if (SymType == SymbolRef::ST_Unknown || RangeOverflow) {
1387 // It is an external symbol (SymbolRef::ST_Unknown) or within a range
1388 // larger than 24-bits.
1389 StubMap::const_iterator i = Stubs.find(Value);
1390 if (i != Stubs.end()) {
1391 // Symbol function stub already created, just relocate to it
1392 resolveRelocation(Section, Offset,
1393 (uint64_t)Section.Address + i->second, RelType, 0);
1394 DEBUG(dbgs() << " Stub function found\n");
1396 // Create a new stub function.
1397 DEBUG(dbgs() << " Create a new stub function\n");
1398 Stubs[Value] = Section.StubOffset;
1399 uint8_t *StubTargetAddr =
1400 createStubFunction(Section.Address + Section.StubOffset,
1402 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
1403 ELF::R_PPC64_ADDR64, Value.Addend);
1405 // Generates the 64-bits address loads as exemplified in section
1406 // 4.5.1 in PPC64 ELF ABI. Note that the relocations need to
1407 // apply to the low part of the instructions, so we have to update
1408 // the offset according to the target endianness.
1409 uint64_t StubRelocOffset = StubTargetAddr - Section.Address;
1410 if (!IsTargetLittleEndian)
1411 StubRelocOffset += 2;
1413 RelocationEntry REhst(SectionID, StubRelocOffset + 0,
1414 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1415 RelocationEntry REhr(SectionID, StubRelocOffset + 4,
1416 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1417 RelocationEntry REh(SectionID, StubRelocOffset + 12,
1418 ELF::R_PPC64_ADDR16_HI, Value.Addend);
1419 RelocationEntry REl(SectionID, StubRelocOffset + 16,
1420 ELF::R_PPC64_ADDR16_LO, Value.Addend);
1422 if (Value.SymbolName) {
1423 addRelocationForSymbol(REhst, Value.SymbolName);
1424 addRelocationForSymbol(REhr, Value.SymbolName);
1425 addRelocationForSymbol(REh, Value.SymbolName);
1426 addRelocationForSymbol(REl, Value.SymbolName);
1428 addRelocationForSection(REhst, Value.SectionID);
1429 addRelocationForSection(REhr, Value.SectionID);
1430 addRelocationForSection(REh, Value.SectionID);
1431 addRelocationForSection(REl, Value.SectionID);
1434 resolveRelocation(Section, Offset,
1435 (uint64_t)Section.Address + Section.StubOffset,
1437 Section.StubOffset += getMaxStubSize();
1439 if (SymType == SymbolRef::ST_Unknown) {
1440 // Restore the TOC for external calls
1441 if (AbiVariant == 2)
1442 writeInt32BE(Target + 4, 0xE8410018); // ld r2,28(r1)
1444 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1)
1447 } else if (RelType == ELF::R_PPC64_TOC16 ||
1448 RelType == ELF::R_PPC64_TOC16_DS ||
1449 RelType == ELF::R_PPC64_TOC16_LO ||
1450 RelType == ELF::R_PPC64_TOC16_LO_DS ||
1451 RelType == ELF::R_PPC64_TOC16_HI ||
1452 RelType == ELF::R_PPC64_TOC16_HA) {
1453 // These relocations are supposed to subtract the TOC address from
1454 // the final value. This does not fit cleanly into the RuntimeDyld
1455 // scheme, since there may be *two* sections involved in determining
1456 // the relocation value (the section of the symbol refered to by the
1457 // relocation, and the TOC section associated with the current module).
1459 // Fortunately, these relocations are currently only ever generated
1460 // refering to symbols that themselves reside in the TOC, which means
1461 // that the two sections are actually the same. Thus they cancel out
1462 // and we can immediately resolve the relocation right now.
1464 case ELF::R_PPC64_TOC16: RelType = ELF::R_PPC64_ADDR16; break;
1465 case ELF::R_PPC64_TOC16_DS: RelType = ELF::R_PPC64_ADDR16_DS; break;
1466 case ELF::R_PPC64_TOC16_LO: RelType = ELF::R_PPC64_ADDR16_LO; break;
1467 case ELF::R_PPC64_TOC16_LO_DS: RelType = ELF::R_PPC64_ADDR16_LO_DS; break;
1468 case ELF::R_PPC64_TOC16_HI: RelType = ELF::R_PPC64_ADDR16_HI; break;
1469 case ELF::R_PPC64_TOC16_HA: RelType = ELF::R_PPC64_ADDR16_HA; break;
1470 default: llvm_unreachable("Wrong relocation type.");
1473 RelocationValueRef TOCValue;
1474 findPPC64TOCSection(Obj, ObjSectionToID, TOCValue);
1475 if (Value.SymbolName || Value.SectionID != TOCValue.SectionID)
1476 llvm_unreachable("Unsupported TOC relocation.");
1477 Value.Addend -= TOCValue.Addend;
1478 resolveRelocation(Sections[SectionID], Offset, Value.Addend, RelType, 0);
1480 // There are two ways to refer to the TOC address directly: either
1481 // via a ELF::R_PPC64_TOC relocation (where both symbol and addend are
1482 // ignored), or via any relocation that refers to the magic ".TOC."
1483 // symbols (in which case the addend is respected).
1484 if (RelType == ELF::R_PPC64_TOC) {
1485 RelType = ELF::R_PPC64_ADDR64;
1486 findPPC64TOCSection(Obj, ObjSectionToID, Value);
1487 } else if (TargetName == ".TOC.") {
1488 findPPC64TOCSection(Obj, ObjSectionToID, Value);
1489 Value.Addend += Addend;
1492 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1494 if (Value.SymbolName)
1495 addRelocationForSymbol(RE, Value.SymbolName);
1497 addRelocationForSection(RE, Value.SectionID);
1499 } else if (Arch == Triple::systemz &&
1500 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) {
1501 // Create function stubs for both PLT and GOT references, regardless of
1502 // whether the GOT reference is to data or code. The stub contains the
1503 // full address of the symbol, as needed by GOT references, and the
1504 // executable part only adds an overhead of 8 bytes.
1506 // We could try to conserve space by allocating the code and data
1507 // parts of the stub separately. However, as things stand, we allocate
1508 // a stub for every relocation, so using a GOT in JIT code should be
1509 // no less space efficient than using an explicit constant pool.
1510 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1511 SectionEntry &Section = Sections[SectionID];
1513 // Look for an existing stub.
1514 StubMap::const_iterator i = Stubs.find(Value);
1515 uintptr_t StubAddress;
1516 if (i != Stubs.end()) {
1517 StubAddress = uintptr_t(Section.Address) + i->second;
1518 DEBUG(dbgs() << " Stub function found\n");
1520 // Create a new stub function.
1521 DEBUG(dbgs() << " Create a new stub function\n");
1523 uintptr_t BaseAddress = uintptr_t(Section.Address);
1524 uintptr_t StubAlignment = getStubAlignment();
1525 StubAddress = (BaseAddress + Section.StubOffset + StubAlignment - 1) &
1527 unsigned StubOffset = StubAddress - BaseAddress;
1529 Stubs[Value] = StubOffset;
1530 createStubFunction((uint8_t *)StubAddress);
1531 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
1533 if (Value.SymbolName)
1534 addRelocationForSymbol(RE, Value.SymbolName);
1536 addRelocationForSection(RE, Value.SectionID);
1537 Section.StubOffset = StubOffset + getMaxStubSize();
1540 if (RelType == ELF::R_390_GOTENT)
1541 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL,
1544 resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1545 } else if (Arch == Triple::x86_64) {
1546 if (RelType == ELF::R_X86_64_PLT32) {
1547 // The way the PLT relocations normally work is that the linker allocates
1549 // PLT and this relocation makes a PC-relative call into the PLT. The PLT
1550 // entry will then jump to an address provided by the GOT. On first call,
1552 // GOT address will point back into PLT code that resolves the symbol. After
1553 // the first call, the GOT entry points to the actual function.
1555 // For local functions we're ignoring all of that here and just replacing
1556 // the PLT32 relocation type with PC32, which will translate the relocation
1557 // into a PC-relative call directly to the function. For external symbols we
1558 // can't be sure the function will be within 2^32 bytes of the call site, so
1559 // we need to create a stub, which calls into the GOT. This case is
1560 // equivalent to the usual PLT implementation except that we use the stub
1561 // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1562 // rather than allocating a PLT section.
1563 if (Value.SymbolName) {
1564 // This is a call to an external function.
1565 // Look for an existing stub.
1566 SectionEntry &Section = Sections[SectionID];
1567 StubMap::const_iterator i = Stubs.find(Value);
1568 uintptr_t StubAddress;
1569 if (i != Stubs.end()) {
1570 StubAddress = uintptr_t(Section.Address) + i->second;
1571 DEBUG(dbgs() << " Stub function found\n");
1573 // Create a new stub function (equivalent to a PLT entry).
1574 DEBUG(dbgs() << " Create a new stub function\n");
1576 uintptr_t BaseAddress = uintptr_t(Section.Address);
1577 uintptr_t StubAlignment = getStubAlignment();
1578 StubAddress = (BaseAddress + Section.StubOffset + StubAlignment - 1) &
1580 unsigned StubOffset = StubAddress - BaseAddress;
1581 Stubs[Value] = StubOffset;
1582 createStubFunction((uint8_t *)StubAddress);
1584 // Bump our stub offset counter
1585 Section.StubOffset = StubOffset + getMaxStubSize();
1587 // Allocate a GOT Entry
1588 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1);
1590 // The load of the GOT address has an addend of -4
1591 resolveGOTOffsetRelocation(SectionID, StubOffset + 2, GOTOffset - 4);
1593 // Fill in the value of the symbol we're targeting into the GOT
1594 addRelocationForSymbol(computeGOTOffsetRE(SectionID,GOTOffset,0,ELF::R_X86_64_64),
1598 // Make the target call a call into the stub table.
1599 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32,
1602 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1604 addRelocationForSection(RE, Value.SectionID);
1606 } else if (RelType == ELF::R_X86_64_GOTPCREL) {
1607 uint64_t GOTOffset = allocateGOTEntries(SectionID, 1);
1608 resolveGOTOffsetRelocation(SectionID, Offset, GOTOffset + Addend);
1610 // Fill in the value of the symbol we're targeting into the GOT
1611 RelocationEntry RE = computeGOTOffsetRE(SectionID, GOTOffset, Value.Offset, ELF::R_X86_64_64);
1612 if (Value.SymbolName)
1613 addRelocationForSymbol(RE, Value.SymbolName);
1615 addRelocationForSection(RE, Value.SectionID);
1616 } else if (RelType == ELF::R_X86_64_PC32) {
1617 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1618 processSimpleRelocation(SectionID, Offset, RelType, Value);
1619 } else if (RelType == ELF::R_X86_64_PC64) {
1620 Value.Addend += support::ulittle64_t::ref(computePlaceholderAddress(SectionID, Offset));
1621 processSimpleRelocation(SectionID, Offset, RelType, Value);
1623 processSimpleRelocation(SectionID, Offset, RelType, Value);
1626 if (Arch == Triple::x86) {
1627 Value.Addend += support::ulittle32_t::ref(computePlaceholderAddress(SectionID, Offset));
1629 processSimpleRelocation(SectionID, Offset, RelType, Value);
1634 size_t RuntimeDyldELF::getGOTEntrySize() {
1635 // We don't use the GOT in all of these cases, but it's essentially free
1636 // to put them all here.
1639 case Triple::x86_64:
1640 case Triple::aarch64:
1641 case Triple::aarch64_be:
1643 case Triple::ppc64le:
1644 case Triple::systemz:
1645 Result = sizeof(uint64_t);
1650 Result = sizeof(uint32_t);
1653 case Triple::mipsel:
1654 case Triple::mips64:
1655 case Triple::mips64el:
1657 Result = sizeof(uint32_t);
1658 else if (IsMipsN64ABI)
1659 Result = sizeof(uint64_t);
1661 llvm_unreachable("Mips ABI not handled");
1664 llvm_unreachable("Unsupported CPU type!");
1669 uint64_t RuntimeDyldELF::allocateGOTEntries(unsigned SectionID, unsigned no)
1671 (void)SectionID; // The GOT Section is the same for all section in the object file
1672 if (GOTSectionID == 0) {
1673 GOTSectionID = Sections.size();
1674 // Reserve a section id. We'll allocate the section later
1675 // once we know the total size
1676 Sections.push_back(SectionEntry(".got", 0, 0, 0));
1678 uint64_t StartOffset = CurrentGOTIndex * getGOTEntrySize();
1679 CurrentGOTIndex += no;
1683 void RuntimeDyldELF::resolveGOTOffsetRelocation(unsigned SectionID, uint64_t Offset, uint64_t GOTOffset)
1685 // Fill in the relative address of the GOT Entry into the stub
1686 RelocationEntry GOTRE(SectionID, Offset, ELF::R_X86_64_PC32, GOTOffset);
1687 addRelocationForSection(GOTRE, GOTSectionID);
1690 RelocationEntry RuntimeDyldELF::computeGOTOffsetRE(unsigned SectionID, uint64_t GOTOffset, uint64_t SymbolOffset,
1693 (void)SectionID; // The GOT Section is the same for all section in the object file
1694 return RelocationEntry(GOTSectionID, GOTOffset, Type, SymbolOffset);
1697 void RuntimeDyldELF::finalizeLoad(const ObjectFile &Obj,
1698 ObjSectionToIDMap &SectionMap) {
1699 // If necessary, allocate the global offset table
1700 if (GOTSectionID != 0) {
1701 // Allocate memory for the section
1702 size_t TotalSize = CurrentGOTIndex * getGOTEntrySize();
1703 uint8_t *Addr = MemMgr.allocateDataSection(TotalSize, getGOTEntrySize(),
1704 GOTSectionID, ".got", false);
1706 report_fatal_error("Unable to allocate memory for GOT!");
1708 Sections[GOTSectionID] = SectionEntry(".got", Addr, TotalSize, 0);
1711 Checker->registerSection(Obj.getFileName(), GOTSectionID);
1713 // For now, initialize all GOT entries to zero. We'll fill them in as
1714 // needed when GOT-based relocations are applied.
1715 memset(Addr, 0, TotalSize);
1717 // To correctly resolve Mips GOT relocations, we need a mapping from
1718 // object's sections to GOTs.
1719 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
1721 if (SI->relocation_begin() != SI->relocation_end()) {
1722 section_iterator RelocatedSection = SI->getRelocatedSection();
1723 ObjSectionToIDMap::iterator i = SectionMap.find(*RelocatedSection);
1724 assert (i != SectionMap.end());
1725 SectionToGOTMap[i->second] = GOTSectionID;
1728 GOTSymbolOffsets.clear();
1732 // Look for and record the EH frame section.
1733 ObjSectionToIDMap::iterator i, e;
1734 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1735 const SectionRef &Section = i->first;
1737 Section.getName(Name);
1738 if (Name == ".eh_frame") {
1739 UnregisteredEHFrameSections.push_back(i->second);
1745 CurrentGOTIndex = 0;
1748 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile &Obj) const {