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 "JITRegistrar.h"
16 #include "ObjectImageCommon.h"
17 #include "llvm/ADT/IntervalMap.h"
18 #include "llvm/ADT/STLExtras.h"
19 #include "llvm/ADT/StringRef.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/ExecutionEngine/ObjectBuffer.h"
22 #include "llvm/ExecutionEngine/ObjectImage.h"
23 #include "llvm/Object/ELFObjectFile.h"
24 #include "llvm/Object/ObjectFile.h"
25 #include "llvm/Support/ELF.h"
26 #include "llvm/Support/MemoryBuffer.h"
29 using namespace llvm::object;
31 #define DEBUG_TYPE "dyld"
35 static inline error_code check(error_code Err) {
37 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;
54 std::unique_ptr<ObjectFile> UnderlyingFile;
57 DyldELFObject(std::unique_ptr<ObjectFile> UnderlyingFile,
58 MemoryBuffer *Wrapper, error_code &ec);
60 DyldELFObject(MemoryBuffer *Wrapper, error_code &ec);
62 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
63 void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr);
65 // Methods for type inquiry through isa, cast and dyn_cast
66 static inline bool classof(const Binary *v) {
67 return (isa<ELFObjectFile<ELFT>>(v) &&
68 classof(cast<ELFObjectFile<ELFT>>(v)));
70 static inline bool classof(const ELFObjectFile<ELFT> *v) {
71 return v->isDyldType();
75 template <class ELFT> class ELFObjectImage : public ObjectImageCommon {
79 ELFObjectImage(ObjectBuffer *Input, std::unique_ptr<DyldELFObject<ELFT>> Obj)
80 : ObjectImageCommon(Input, std::move(Obj)), Registered(false) {}
82 virtual ~ELFObjectImage() {
84 deregisterWithDebugger();
87 // Subclasses can override these methods to update the image with loaded
88 // addresses for sections and common symbols
89 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr) override {
90 static_cast<DyldELFObject<ELFT>*>(getObjectFile())
91 ->updateSectionAddress(Sec, Addr);
94 void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr) override {
95 static_cast<DyldELFObject<ELFT>*>(getObjectFile())
96 ->updateSymbolAddress(Sym, Addr);
99 void registerWithDebugger() override {
100 JITRegistrar::getGDBRegistrar().registerObject(*Buffer);
103 void deregisterWithDebugger() override {
104 JITRegistrar::getGDBRegistrar().deregisterObject(*Buffer);
108 // The MemoryBuffer passed into this constructor is just a wrapper around the
109 // actual memory. Ultimately, the Binary parent class will take ownership of
110 // this MemoryBuffer object but not the underlying memory.
111 template <class ELFT>
112 DyldELFObject<ELFT>::DyldELFObject(MemoryBuffer *Wrapper, error_code &ec)
113 : ELFObjectFile<ELFT>(Wrapper, ec) {
114 this->isDyldELFObject = true;
117 template <class ELFT>
118 DyldELFObject<ELFT>::DyldELFObject(std::unique_ptr<ObjectFile> UnderlyingFile,
119 MemoryBuffer *Wrapper, error_code &ec)
120 : ELFObjectFile<ELFT>(Wrapper, ec),
121 UnderlyingFile(std::move(UnderlyingFile)) {
122 this->isDyldELFObject = true;
125 template <class ELFT>
126 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
128 DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
130 const_cast<Elf_Shdr *>(reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
132 // This assumes the address passed in matches the target address bitness
133 // The template-based type cast handles everything else.
134 shdr->sh_addr = static_cast<addr_type>(Addr);
137 template <class ELFT>
138 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
141 Elf_Sym *sym = const_cast<Elf_Sym *>(
142 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl()));
144 // This assumes the address passed in matches the target address bitness
145 // The template-based type cast handles everything else.
146 sym->st_value = static_cast<addr_type>(Addr);
153 void RuntimeDyldELF::registerEHFrames() {
156 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
157 SID EHFrameSID = UnregisteredEHFrameSections[i];
158 uint8_t *EHFrameAddr = Sections[EHFrameSID].Address;
159 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress;
160 size_t EHFrameSize = Sections[EHFrameSID].Size;
161 MemMgr->registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
162 RegisteredEHFrameSections.push_back(EHFrameSID);
164 UnregisteredEHFrameSections.clear();
167 void RuntimeDyldELF::deregisterEHFrames() {
170 for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) {
171 SID EHFrameSID = RegisteredEHFrameSections[i];
172 uint8_t *EHFrameAddr = Sections[EHFrameSID].Address;
173 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress;
174 size_t EHFrameSize = Sections[EHFrameSID].Size;
175 MemMgr->deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
177 RegisteredEHFrameSections.clear();
181 RuntimeDyldELF::createObjectImageFromFile(std::unique_ptr<object::ObjectFile> ObjFile) {
186 MemoryBuffer *Buffer =
187 MemoryBuffer::getMemBuffer(ObjFile->getData(), "", false);
189 if (ObjFile->getBytesInAddress() == 4 && ObjFile->isLittleEndian()) {
190 auto Obj = make_unique<DyldELFObject<ELFType<support::little, 2, false>>>(std::move(ObjFile), Buffer, ec);
191 return new ELFObjectImage<ELFType<support::little, 2, false>>(
192 nullptr, std::move(Obj));
193 } else if (ObjFile->getBytesInAddress() == 4 && !ObjFile->isLittleEndian()) {
194 auto Obj = make_unique<DyldELFObject<ELFType<support::big, 2, false>>>(
195 std::move(ObjFile), Buffer, ec);
196 return new ELFObjectImage<ELFType<support::big, 2, false>>(nullptr, std::move(Obj));
197 } else if (ObjFile->getBytesInAddress() == 8 && !ObjFile->isLittleEndian()) {
198 auto Obj = make_unique<DyldELFObject<ELFType<support::big, 2, true>>>(
199 std::move(ObjFile), Buffer, ec);
200 return new ELFObjectImage<ELFType<support::big, 2, true>>(nullptr,
202 } else if (ObjFile->getBytesInAddress() == 8 && ObjFile->isLittleEndian()) {
203 auto Obj = make_unique<DyldELFObject<ELFType<support::little, 2, true>>>(
204 std::move(ObjFile), Buffer, ec);
205 return new ELFObjectImage<ELFType<support::little, 2, true>>(
206 nullptr, std::move(Obj));
208 llvm_unreachable("Unexpected ELF format");
211 ObjectImage *RuntimeDyldELF::createObjectImage(ObjectBuffer *Buffer) {
212 if (Buffer->getBufferSize() < ELF::EI_NIDENT)
213 llvm_unreachable("Unexpected ELF object size");
214 std::pair<unsigned char, unsigned char> Ident =
215 std::make_pair((uint8_t)Buffer->getBufferStart()[ELF::EI_CLASS],
216 (uint8_t)Buffer->getBufferStart()[ELF::EI_DATA]);
219 if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB) {
220 auto Obj = make_unique<DyldELFObject<ELFType<support::little, 4, false>>>(
221 Buffer->getMemBuffer(), ec);
222 return new ELFObjectImage<ELFType<support::little, 4, false>>(
223 Buffer, std::move(Obj));
224 } else if (Ident.first == ELF::ELFCLASS32 &&
225 Ident.second == ELF::ELFDATA2MSB) {
227 make_unique<DyldELFObject<ELFType<support::big, 4, false>>>(
228 Buffer->getMemBuffer(), ec);
229 return new ELFObjectImage<ELFType<support::big, 4, false>>(Buffer,
231 } else if (Ident.first == ELF::ELFCLASS64 &&
232 Ident.second == ELF::ELFDATA2MSB) {
234 make_unique<DyldELFObject<ELFType<support::big, 8, true>>>(
235 Buffer->getMemBuffer(), ec);
236 return new ELFObjectImage<ELFType<support::big, 8, true>>(Buffer, std::move(Obj));
237 } else if (Ident.first == ELF::ELFCLASS64 &&
238 Ident.second == ELF::ELFDATA2LSB) {
240 make_unique<DyldELFObject<ELFType<support::little, 8, true>>>(
241 Buffer->getMemBuffer(), ec);
242 return new ELFObjectImage<ELFType<support::little, 8, true>>(Buffer, std::move(Obj));
244 llvm_unreachable("Unexpected ELF format");
247 RuntimeDyldELF::~RuntimeDyldELF() {}
249 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
250 uint64_t Offset, uint64_t Value,
251 uint32_t Type, int64_t Addend,
252 uint64_t SymOffset) {
255 llvm_unreachable("Relocation type not implemented yet!");
257 case ELF::R_X86_64_64: {
258 uint64_t *Target = reinterpret_cast<uint64_t *>(Section.Address + Offset);
259 *Target = Value + Addend;
260 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) << " at "
261 << format("%p\n", Target));
264 case ELF::R_X86_64_32:
265 case ELF::R_X86_64_32S: {
267 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
268 (Type == ELF::R_X86_64_32S &&
269 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
270 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
271 uint32_t *Target = reinterpret_cast<uint32_t *>(Section.Address + Offset);
272 *Target = TruncatedAddr;
273 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) << " at "
274 << format("%p\n", Target));
277 case ELF::R_X86_64_GOTPCREL: {
278 // findGOTEntry returns the 'G + GOT' part of the relocation calculation
279 // based on the load/target address of the GOT (not the current/local addr).
280 uint64_t GOTAddr = findGOTEntry(Value, SymOffset);
281 uint32_t *Target = reinterpret_cast<uint32_t *>(Section.Address + Offset);
282 uint64_t FinalAddress = Section.LoadAddress + Offset;
283 // The processRelocationRef method combines the symbol offset and the addend
284 // and in most cases that's what we want. For this relocation type, we need
285 // the raw addend, so we subtract the symbol offset to get it.
286 int64_t RealOffset = GOTAddr + Addend - SymOffset - FinalAddress;
287 assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);
288 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
289 *Target = TruncOffset;
292 case ELF::R_X86_64_PC32: {
293 // Get the placeholder value from the generated object since
294 // a previous relocation attempt may have overwritten the loaded version
295 uint32_t *Placeholder =
296 reinterpret_cast<uint32_t *>(Section.ObjAddress + Offset);
297 uint32_t *Target = reinterpret_cast<uint32_t *>(Section.Address + Offset);
298 uint64_t FinalAddress = Section.LoadAddress + Offset;
299 int64_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
300 assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);
301 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
302 *Target = TruncOffset;
305 case ELF::R_X86_64_PC64: {
306 // Get the placeholder value from the generated object since
307 // a previous relocation attempt may have overwritten the loaded version
308 uint64_t *Placeholder =
309 reinterpret_cast<uint64_t *>(Section.ObjAddress + Offset);
310 uint64_t *Target = reinterpret_cast<uint64_t *>(Section.Address + Offset);
311 uint64_t FinalAddress = Section.LoadAddress + Offset;
312 *Target = *Placeholder + Value + Addend - FinalAddress;
318 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
319 uint64_t Offset, uint32_t Value,
320 uint32_t Type, int32_t Addend) {
322 case ELF::R_386_32: {
323 // Get the placeholder value from the generated object since
324 // a previous relocation attempt may have overwritten the loaded version
325 uint32_t *Placeholder =
326 reinterpret_cast<uint32_t *>(Section.ObjAddress + Offset);
327 uint32_t *Target = reinterpret_cast<uint32_t *>(Section.Address + Offset);
328 *Target = *Placeholder + Value + Addend;
331 case ELF::R_386_PC32: {
332 // Get the placeholder value from the generated object since
333 // a previous relocation attempt may have overwritten the loaded version
334 uint32_t *Placeholder =
335 reinterpret_cast<uint32_t *>(Section.ObjAddress + Offset);
336 uint32_t *Target = reinterpret_cast<uint32_t *>(Section.Address + Offset);
337 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
338 uint32_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
339 *Target = RealOffset;
343 // There are other relocation types, but it appears these are the
344 // only ones currently used by the LLVM ELF object writer
345 llvm_unreachable("Relocation type not implemented yet!");
350 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
351 uint64_t Offset, uint64_t Value,
352 uint32_t Type, int64_t Addend) {
353 uint32_t *TargetPtr = reinterpret_cast<uint32_t *>(Section.Address + Offset);
354 uint64_t FinalAddress = Section.LoadAddress + Offset;
356 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
357 << format("%llx", Section.Address + Offset)
358 << " FinalAddress: 0x" << format("%llx", FinalAddress)
359 << " Value: 0x" << format("%llx", Value) << " Type: 0x"
360 << format("%x", Type) << " Addend: 0x" << format("%llx", Addend)
365 llvm_unreachable("Relocation type not implemented yet!");
367 case ELF::R_AARCH64_ABS64: {
368 uint64_t *TargetPtr =
369 reinterpret_cast<uint64_t *>(Section.Address + Offset);
370 *TargetPtr = Value + Addend;
373 case ELF::R_AARCH64_PREL32: {
374 uint64_t Result = Value + Addend - FinalAddress;
375 assert(static_cast<int64_t>(Result) >= INT32_MIN &&
376 static_cast<int64_t>(Result) <= UINT32_MAX);
377 *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU);
380 case ELF::R_AARCH64_CALL26: // fallthrough
381 case ELF::R_AARCH64_JUMP26: {
382 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
384 uint64_t BranchImm = Value + Addend - FinalAddress;
386 // "Check that -2^27 <= result < 2^27".
387 assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) &&
388 static_cast<int64_t>(BranchImm) < (1LL << 27));
390 // AArch64 code is emitted with .rela relocations. The data already in any
391 // bits affected by the relocation on entry is garbage.
392 *TargetPtr &= 0xfc000000U;
393 // Immediate goes in bits 25:0 of B and BL.
394 *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2;
397 case ELF::R_AARCH64_MOVW_UABS_G3: {
398 uint64_t Result = Value + Addend;
400 // AArch64 code is emitted with .rela relocations. The data already in any
401 // bits affected by the relocation on entry is garbage.
402 *TargetPtr &= 0xffe0001fU;
403 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
404 *TargetPtr |= Result >> (48 - 5);
405 // Shift must be "lsl #48", in bits 22:21
406 assert((*TargetPtr >> 21 & 0x3) == 3 && "invalid shift for relocation");
409 case ELF::R_AARCH64_MOVW_UABS_G2_NC: {
410 uint64_t Result = Value + Addend;
412 // AArch64 code is emitted with .rela relocations. The data already in any
413 // bits affected by the relocation on entry is garbage.
414 *TargetPtr &= 0xffe0001fU;
415 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
416 *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5));
417 // Shift must be "lsl #32", in bits 22:21
418 assert((*TargetPtr >> 21 & 0x3) == 2 && "invalid shift for relocation");
421 case ELF::R_AARCH64_MOVW_UABS_G1_NC: {
422 uint64_t Result = Value + Addend;
424 // AArch64 code is emitted with .rela relocations. The data already in any
425 // bits affected by the relocation on entry is garbage.
426 *TargetPtr &= 0xffe0001fU;
427 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
428 *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5));
429 // Shift must be "lsl #16", in bits 22:2
430 assert((*TargetPtr >> 21 & 0x3) == 1 && "invalid shift for relocation");
433 case ELF::R_AARCH64_MOVW_UABS_G0_NC: {
434 uint64_t Result = Value + Addend;
436 // AArch64 code is emitted with .rela relocations. The data already in any
437 // bits affected by the relocation on entry is garbage.
438 *TargetPtr &= 0xffe0001fU;
439 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
440 *TargetPtr |= ((Result & 0xffffU) << 5);
441 // Shift must be "lsl #0", in bits 22:21.
442 assert((*TargetPtr >> 21 & 0x3) == 0 && "invalid shift for relocation");
445 case ELF::R_AARCH64_ADR_PREL_PG_HI21: {
446 // Operation: Page(S+A) - Page(P)
448 ((Value + Addend) & ~0xfffULL) - (FinalAddress & ~0xfffULL);
450 // Check that -2^32 <= X < 2^32
451 assert(static_cast<int64_t>(Result) >= (-1LL << 32) &&
452 static_cast<int64_t>(Result) < (1LL << 32) &&
453 "overflow check failed for relocation");
455 // AArch64 code is emitted with .rela relocations. The data already in any
456 // bits affected by the relocation on entry is garbage.
457 *TargetPtr &= 0x9f00001fU;
458 // Immediate goes in bits 30:29 + 5:23 of ADRP instruction, taken
459 // from bits 32:12 of X.
460 *TargetPtr |= ((Result & 0x3000U) << (29 - 12));
461 *TargetPtr |= ((Result & 0x1ffffc000ULL) >> (14 - 5));
464 case ELF::R_AARCH64_LDST32_ABS_LO12_NC: {
466 uint64_t Result = Value + Addend;
468 // AArch64 code is emitted with .rela relocations. The data already in any
469 // bits affected by the relocation on entry is garbage.
470 *TargetPtr &= 0xffc003ffU;
471 // Immediate goes in bits 21:10 of LD/ST instruction, taken
472 // from bits 11:2 of X
473 *TargetPtr |= ((Result & 0xffc) << (10 - 2));
476 case ELF::R_AARCH64_LDST64_ABS_LO12_NC: {
478 uint64_t Result = Value + Addend;
480 // AArch64 code is emitted with .rela relocations. The data already in any
481 // bits affected by the relocation on entry is garbage.
482 *TargetPtr &= 0xffc003ffU;
483 // Immediate goes in bits 21:10 of LD/ST instruction, taken
484 // from bits 11:3 of X
485 *TargetPtr |= ((Result & 0xff8) << (10 - 3));
491 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
492 uint64_t Offset, uint32_t Value,
493 uint32_t Type, int32_t Addend) {
494 // TODO: Add Thumb relocations.
495 uint32_t *Placeholder =
496 reinterpret_cast<uint32_t *>(Section.ObjAddress + Offset);
497 uint32_t *TargetPtr = (uint32_t *)(Section.Address + Offset);
498 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
501 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
502 << Section.Address + Offset
503 << " FinalAddress: " << format("%p", FinalAddress) << " Value: "
504 << format("%x", Value) << " Type: " << format("%x", Type)
505 << " Addend: " << format("%x", Addend) << "\n");
509 llvm_unreachable("Not implemented relocation type!");
511 case ELF::R_ARM_NONE:
513 // Write a 32bit value to relocation address, taking into account the
514 // implicit addend encoded in the target.
515 case ELF::R_ARM_PREL31:
516 case ELF::R_ARM_TARGET1:
517 case ELF::R_ARM_ABS32:
518 *TargetPtr = *Placeholder + Value;
520 // Write first 16 bit of 32 bit value to the mov instruction.
521 // Last 4 bit should be shifted.
522 case ELF::R_ARM_MOVW_ABS_NC:
523 // We are not expecting any other addend in the relocation address.
524 // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2
525 // non-contiguous fields.
526 assert((*Placeholder & 0x000F0FFF) == 0);
527 Value = Value & 0xFFFF;
528 *TargetPtr = *Placeholder | (Value & 0xFFF);
529 *TargetPtr |= ((Value >> 12) & 0xF) << 16;
531 // Write last 16 bit of 32 bit value to the mov instruction.
532 // Last 4 bit should be shifted.
533 case ELF::R_ARM_MOVT_ABS:
534 // We are not expecting any other addend in the relocation address.
535 // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC.
536 assert((*Placeholder & 0x000F0FFF) == 0);
538 Value = (Value >> 16) & 0xFFFF;
539 *TargetPtr = *Placeholder | (Value & 0xFFF);
540 *TargetPtr |= ((Value >> 12) & 0xF) << 16;
542 // Write 24 bit relative value to the branch instruction.
543 case ELF::R_ARM_PC24: // Fall through.
544 case ELF::R_ARM_CALL: // Fall through.
545 case ELF::R_ARM_JUMP24: {
546 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
547 RelValue = (RelValue & 0x03FFFFFC) >> 2;
548 assert((*TargetPtr & 0xFFFFFF) == 0xFFFFFE);
549 *TargetPtr &= 0xFF000000;
550 *TargetPtr |= RelValue;
553 case ELF::R_ARM_PRIVATE_0:
554 // This relocation is reserved by the ARM ELF ABI for internal use. We
555 // appropriate it here to act as an R_ARM_ABS32 without any addend for use
556 // in the stubs created during JIT (which can't put an addend into the
557 // original object file).
563 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section,
564 uint64_t Offset, uint32_t Value,
565 uint32_t Type, int32_t Addend) {
566 uint32_t *Placeholder =
567 reinterpret_cast<uint32_t *>(Section.ObjAddress + Offset);
568 uint32_t *TargetPtr = (uint32_t *)(Section.Address + Offset);
571 DEBUG(dbgs() << "resolveMipselocation, LocalAddress: "
572 << Section.Address + Offset << " FinalAddress: "
573 << format("%p", Section.LoadAddress + Offset) << " Value: "
574 << format("%x", Value) << " Type: " << format("%x", Type)
575 << " Addend: " << format("%x", Addend) << "\n");
579 llvm_unreachable("Not implemented relocation type!");
582 *TargetPtr = Value + (*Placeholder);
585 *TargetPtr = ((*Placeholder) & 0xfc000000) | ((Value & 0x0fffffff) >> 2);
587 case ELF::R_MIPS_HI16:
588 // Get the higher 16-bits. Also add 1 if bit 15 is 1.
589 Value += ((*Placeholder) & 0x0000ffff) << 16;
591 ((*Placeholder) & 0xffff0000) | (((Value + 0x8000) >> 16) & 0xffff);
593 case ELF::R_MIPS_LO16:
594 Value += ((*Placeholder) & 0x0000ffff);
595 *TargetPtr = ((*Placeholder) & 0xffff0000) | (Value & 0xffff);
597 case ELF::R_MIPS_UNUSED1:
598 // Similar to ELF::R_ARM_PRIVATE_0, R_MIPS_UNUSED1 and R_MIPS_UNUSED2
599 // are used for internal JIT purpose. These relocations are similar to
600 // R_MIPS_HI16 and R_MIPS_LO16, but they do not take any addend into
603 ((*TargetPtr) & 0xffff0000) | (((Value + 0x8000) >> 16) & 0xffff);
605 case ELF::R_MIPS_UNUSED2:
606 *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff);
611 // Return the .TOC. section address to R_PPC64_TOC relocations.
612 uint64_t RuntimeDyldELF::findPPC64TOC() const {
613 // The TOC consists of sections .got, .toc, .tocbss, .plt in that
614 // order. The TOC starts where the first of these sections starts.
615 SectionList::const_iterator it = Sections.begin();
616 SectionList::const_iterator ite = Sections.end();
617 for (; it != ite; ++it) {
618 if (it->Name == ".got" || it->Name == ".toc" || it->Name == ".tocbss" ||
623 // This may happen for
624 // * references to TOC base base (sym@toc, .odp relocation) without
626 // In this case just use the first section (which is usually
627 // the .odp) since the code won't reference the .toc base
629 it = Sections.begin();
632 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
633 // thus permitting a full 64 Kbytes segment.
634 return it->LoadAddress + 0x8000;
637 // Returns the sections and offset associated with the ODP entry referenced
639 void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj,
640 ObjSectionToIDMap &LocalSections,
641 RelocationValueRef &Rel) {
642 // Get the ELF symbol value (st_value) to compare with Relocation offset in
644 for (section_iterator si = Obj.begin_sections(), se = Obj.end_sections();
646 section_iterator RelSecI = si->getRelocatedSection();
647 if (RelSecI == Obj.end_sections())
650 StringRef RelSectionName;
651 check(RelSecI->getName(RelSectionName));
652 if (RelSectionName != ".opd")
655 for (relocation_iterator i = si->relocation_begin(),
656 e = si->relocation_end();
658 // The R_PPC64_ADDR64 relocation indicates the first field
661 check(i->getType(TypeFunc));
662 if (TypeFunc != ELF::R_PPC64_ADDR64) {
667 uint64_t TargetSymbolOffset;
668 symbol_iterator TargetSymbol = i->getSymbol();
669 check(i->getOffset(TargetSymbolOffset));
671 check(getELFRelocationAddend(*i, Addend));
677 // Just check if following relocation is a R_PPC64_TOC
679 check(i->getType(TypeTOC));
680 if (TypeTOC != ELF::R_PPC64_TOC)
683 // Finally compares the Symbol value and the target symbol offset
684 // to check if this .opd entry refers to the symbol the relocation
686 if (Rel.Addend != (int64_t)TargetSymbolOffset)
689 section_iterator tsi(Obj.end_sections());
690 check(TargetSymbol->getSection(tsi));
693 Rel.SectionID = findOrEmitSection(Obj, (*tsi), IsCode, LocalSections);
694 Rel.Addend = (intptr_t)Addend;
698 llvm_unreachable("Attempting to get address of ODP entry!");
701 // Relocation masks following the #lo(value), #hi(value), #higher(value),
702 // and #highest(value) macros defined in section 4.5.1. Relocation Types
703 // in PPC-elf64abi document.
705 static inline uint16_t applyPPClo(uint64_t value) { return value & 0xffff; }
707 static inline uint16_t applyPPChi(uint64_t value) {
708 return (value >> 16) & 0xffff;
711 static inline uint16_t applyPPChigher(uint64_t value) {
712 return (value >> 32) & 0xffff;
715 static inline uint16_t applyPPChighest(uint64_t value) {
716 return (value >> 48) & 0xffff;
719 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
720 uint64_t Offset, uint64_t Value,
721 uint32_t Type, int64_t Addend) {
722 uint8_t *LocalAddress = Section.Address + Offset;
725 llvm_unreachable("Relocation type not implemented yet!");
727 case ELF::R_PPC64_ADDR16_LO:
728 writeInt16BE(LocalAddress, applyPPClo(Value + Addend));
730 case ELF::R_PPC64_ADDR16_HI:
731 writeInt16BE(LocalAddress, applyPPChi(Value + Addend));
733 case ELF::R_PPC64_ADDR16_HIGHER:
734 writeInt16BE(LocalAddress, applyPPChigher(Value + Addend));
736 case ELF::R_PPC64_ADDR16_HIGHEST:
737 writeInt16BE(LocalAddress, applyPPChighest(Value + Addend));
739 case ELF::R_PPC64_ADDR14: {
740 assert(((Value + Addend) & 3) == 0);
741 // Preserve the AA/LK bits in the branch instruction
742 uint8_t aalk = *(LocalAddress + 3);
743 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
745 case ELF::R_PPC64_ADDR32: {
746 int32_t Result = static_cast<int32_t>(Value + Addend);
747 if (SignExtend32<32>(Result) != Result)
748 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
749 writeInt32BE(LocalAddress, Result);
751 case ELF::R_PPC64_REL24: {
752 uint64_t FinalAddress = (Section.LoadAddress + Offset);
753 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
754 if (SignExtend32<24>(delta) != delta)
755 llvm_unreachable("Relocation R_PPC64_REL24 overflow");
756 // Generates a 'bl <address>' instruction
757 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
759 case ELF::R_PPC64_REL32: {
760 uint64_t FinalAddress = (Section.LoadAddress + Offset);
761 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
762 if (SignExtend32<32>(delta) != delta)
763 llvm_unreachable("Relocation R_PPC64_REL32 overflow");
764 writeInt32BE(LocalAddress, delta);
766 case ELF::R_PPC64_REL64: {
767 uint64_t FinalAddress = (Section.LoadAddress + Offset);
768 uint64_t Delta = Value - FinalAddress + Addend;
769 writeInt64BE(LocalAddress, Delta);
771 case ELF::R_PPC64_ADDR64:
772 writeInt64BE(LocalAddress, Value + Addend);
774 case ELF::R_PPC64_TOC:
775 writeInt64BE(LocalAddress, findPPC64TOC());
777 case ELF::R_PPC64_TOC16: {
778 uint64_t TOCStart = findPPC64TOC();
779 Value = applyPPClo((Value + Addend) - TOCStart);
780 writeInt16BE(LocalAddress, applyPPClo(Value));
782 case ELF::R_PPC64_TOC16_DS: {
783 uint64_t TOCStart = findPPC64TOC();
784 Value = ((Value + Addend) - TOCStart);
785 writeInt16BE(LocalAddress, applyPPClo(Value));
790 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
791 uint64_t Offset, uint64_t Value,
792 uint32_t Type, int64_t Addend) {
793 uint8_t *LocalAddress = Section.Address + Offset;
796 llvm_unreachable("Relocation type not implemented yet!");
798 case ELF::R_390_PC16DBL:
799 case ELF::R_390_PLT16DBL: {
800 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
801 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
802 writeInt16BE(LocalAddress, Delta / 2);
805 case ELF::R_390_PC32DBL:
806 case ELF::R_390_PLT32DBL: {
807 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
808 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
809 writeInt32BE(LocalAddress, Delta / 2);
812 case ELF::R_390_PC32: {
813 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
814 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
815 writeInt32BE(LocalAddress, Delta);
819 writeInt64BE(LocalAddress, Value + Addend);
824 // The target location for the relocation is described by RE.SectionID and
825 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
826 // SectionEntry has three members describing its location.
827 // SectionEntry::Address is the address at which the section has been loaded
828 // into memory in the current (host) process. SectionEntry::LoadAddress is the
829 // address that the section will have in the target process.
830 // SectionEntry::ObjAddress is the address of the bits for this section in the
831 // original emitted object image (also in the current address space).
833 // Relocations will be applied as if the section were loaded at
834 // SectionEntry::LoadAddress, but they will be applied at an address based
835 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to
836 // Target memory contents if they are required for value calculations.
838 // The Value parameter here is the load address of the symbol for the
839 // relocation to be applied. For relocations which refer to symbols in the
840 // current object Value will be the LoadAddress of the section in which
841 // the symbol resides (RE.Addend provides additional information about the
842 // symbol location). For external symbols, Value will be the address of the
843 // symbol in the target address space.
844 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
846 const SectionEntry &Section = Sections[RE.SectionID];
847 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
851 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
852 uint64_t Offset, uint64_t Value,
853 uint32_t Type, int64_t Addend,
854 uint64_t SymOffset) {
857 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
860 resolveX86Relocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
861 (uint32_t)(Addend & 0xffffffffL));
863 case Triple::aarch64:
864 case Triple::aarch64_be:
865 resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
867 case Triple::arm: // Fall through.
870 case Triple::thumbeb:
871 resolveARMRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL), Type,
872 (uint32_t)(Addend & 0xffffffffL));
874 case Triple::mips: // Fall through.
876 resolveMIPSRelocation(Section, Offset, (uint32_t)(Value & 0xffffffffL),
877 Type, (uint32_t)(Addend & 0xffffffffL));
879 case Triple::ppc64: // Fall through.
880 case Triple::ppc64le:
881 resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
883 case Triple::systemz:
884 resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
887 llvm_unreachable("Unsupported CPU type!");
891 relocation_iterator RuntimeDyldELF::processRelocationRef(
892 unsigned SectionID, relocation_iterator RelI, ObjectImage &Obj,
893 ObjSectionToIDMap &ObjSectionToID, const SymbolTableMap &Symbols,
896 Check(RelI->getType(RelType));
898 Check(getELFRelocationAddend(*RelI, Addend));
899 symbol_iterator Symbol = RelI->getSymbol();
901 // Obtain the symbol name which is referenced in the relocation
902 StringRef TargetName;
903 if (Symbol != Obj.end_symbols())
904 Symbol->getName(TargetName);
905 DEBUG(dbgs() << "\t\tRelType: " << RelType << " Addend: " << Addend
906 << " TargetName: " << TargetName << "\n");
907 RelocationValueRef Value;
908 // First search for the symbol in the local symbol table
909 SymbolTableMap::const_iterator lsi = Symbols.end();
910 SymbolRef::Type SymType = SymbolRef::ST_Unknown;
911 if (Symbol != Obj.end_symbols()) {
912 lsi = Symbols.find(TargetName.data());
913 Symbol->getType(SymType);
915 if (lsi != Symbols.end()) {
916 Value.SectionID = lsi->second.first;
917 Value.Offset = lsi->second.second;
918 Value.Addend = lsi->second.second + Addend;
920 // Search for the symbol in the global symbol table
921 SymbolTableMap::const_iterator gsi = GlobalSymbolTable.end();
922 if (Symbol != Obj.end_symbols())
923 gsi = GlobalSymbolTable.find(TargetName.data());
924 if (gsi != GlobalSymbolTable.end()) {
925 Value.SectionID = gsi->second.first;
926 Value.Offset = gsi->second.second;
927 Value.Addend = gsi->second.second + Addend;
930 case SymbolRef::ST_Debug: {
931 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
932 // and can be changed by another developers. Maybe best way is add
933 // a new symbol type ST_Section to SymbolRef and use it.
934 section_iterator si(Obj.end_sections());
935 Symbol->getSection(si);
936 if (si == Obj.end_sections())
937 llvm_unreachable("Symbol section not found, bad object file format!");
938 DEBUG(dbgs() << "\t\tThis is section symbol\n");
939 // Default to 'true' in case isText fails (though it never does).
942 Value.SectionID = findOrEmitSection(Obj, (*si), isCode, ObjSectionToID);
943 Value.Addend = Addend;
946 case SymbolRef::ST_Data:
947 case SymbolRef::ST_Unknown: {
948 Value.SymbolName = TargetName.data();
949 Value.Addend = Addend;
951 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
952 // will manifest here as a NULL symbol name.
953 // We can set this as a valid (but empty) symbol name, and rely
954 // on addRelocationForSymbol to handle this.
955 if (!Value.SymbolName)
956 Value.SymbolName = "";
960 llvm_unreachable("Unresolved symbol type!");
966 Check(RelI->getOffset(Offset));
968 DEBUG(dbgs() << "\t\tSectionID: " << SectionID << " Offset: " << Offset
970 if (Arch == Triple::aarch64 &&
971 (RelType == ELF::R_AARCH64_CALL26 || RelType == ELF::R_AARCH64_JUMP26)) {
972 // This is an AArch64 branch relocation, need to use a stub function.
973 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
974 SectionEntry &Section = Sections[SectionID];
976 // Look for an existing stub.
977 StubMap::const_iterator i = Stubs.find(Value);
978 if (i != Stubs.end()) {
979 resolveRelocation(Section, Offset, (uint64_t)Section.Address + i->second,
981 DEBUG(dbgs() << " Stub function found\n");
983 // Create a new stub function.
984 DEBUG(dbgs() << " Create a new stub function\n");
985 Stubs[Value] = Section.StubOffset;
986 uint8_t *StubTargetAddr =
987 createStubFunction(Section.Address + Section.StubOffset);
989 RelocationEntry REmovz_g3(SectionID, StubTargetAddr - Section.Address,
990 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
991 RelocationEntry REmovk_g2(SectionID, StubTargetAddr - Section.Address + 4,
992 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
993 RelocationEntry REmovk_g1(SectionID, StubTargetAddr - Section.Address + 8,
994 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
995 RelocationEntry REmovk_g0(SectionID,
996 StubTargetAddr - Section.Address + 12,
997 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
999 if (Value.SymbolName) {
1000 addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1001 addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1002 addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1003 addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1005 addRelocationForSection(REmovz_g3, Value.SectionID);
1006 addRelocationForSection(REmovk_g2, Value.SectionID);
1007 addRelocationForSection(REmovk_g1, Value.SectionID);
1008 addRelocationForSection(REmovk_g0, Value.SectionID);
1010 resolveRelocation(Section, Offset,
1011 (uint64_t)Section.Address + Section.StubOffset, RelType,
1013 Section.StubOffset += getMaxStubSize();
1015 } else if (Arch == Triple::arm &&
1016 (RelType == ELF::R_ARM_PC24 || RelType == ELF::R_ARM_CALL ||
1017 RelType == ELF::R_ARM_JUMP24)) {
1018 // This is an ARM branch relocation, need to use a stub function.
1019 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.");
1020 SectionEntry &Section = Sections[SectionID];
1022 // Look for an existing stub.
1023 StubMap::const_iterator i = Stubs.find(Value);
1024 if (i != Stubs.end()) {
1025 resolveRelocation(Section, Offset, (uint64_t)Section.Address + i->second,
1027 DEBUG(dbgs() << " Stub function found\n");
1029 // Create a new stub function.
1030 DEBUG(dbgs() << " Create a new stub function\n");
1031 Stubs[Value] = Section.StubOffset;
1032 uint8_t *StubTargetAddr =
1033 createStubFunction(Section.Address + Section.StubOffset);
1034 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
1035 ELF::R_ARM_PRIVATE_0, Value.Addend);
1036 if (Value.SymbolName)
1037 addRelocationForSymbol(RE, Value.SymbolName);
1039 addRelocationForSection(RE, Value.SectionID);
1041 resolveRelocation(Section, Offset,
1042 (uint64_t)Section.Address + Section.StubOffset, RelType,
1044 Section.StubOffset += getMaxStubSize();
1046 } else if ((Arch == Triple::mipsel || Arch == Triple::mips) &&
1047 RelType == ELF::R_MIPS_26) {
1048 // This is an Mips branch relocation, need to use a stub function.
1049 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1050 SectionEntry &Section = Sections[SectionID];
1051 uint8_t *Target = Section.Address + Offset;
1052 uint32_t *TargetAddress = (uint32_t *)Target;
1054 // Extract the addend from the instruction.
1055 uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2;
1057 Value.Addend += Addend;
1059 // Look up for existing stub.
1060 StubMap::const_iterator i = Stubs.find(Value);
1061 if (i != Stubs.end()) {
1062 RelocationEntry RE(SectionID, Offset, RelType, i->second);
1063 addRelocationForSection(RE, SectionID);
1064 DEBUG(dbgs() << " Stub function found\n");
1066 // Create a new stub function.
1067 DEBUG(dbgs() << " Create a new stub function\n");
1068 Stubs[Value] = Section.StubOffset;
1069 uint8_t *StubTargetAddr =
1070 createStubFunction(Section.Address + Section.StubOffset);
1072 // Creating Hi and Lo relocations for the filled stub instructions.
1073 RelocationEntry REHi(SectionID, StubTargetAddr - Section.Address,
1074 ELF::R_MIPS_UNUSED1, Value.Addend);
1075 RelocationEntry RELo(SectionID, StubTargetAddr - Section.Address + 4,
1076 ELF::R_MIPS_UNUSED2, Value.Addend);
1078 if (Value.SymbolName) {
1079 addRelocationForSymbol(REHi, Value.SymbolName);
1080 addRelocationForSymbol(RELo, Value.SymbolName);
1082 addRelocationForSection(REHi, Value.SectionID);
1083 addRelocationForSection(RELo, Value.SectionID);
1086 RelocationEntry RE(SectionID, Offset, RelType, Section.StubOffset);
1087 addRelocationForSection(RE, SectionID);
1088 Section.StubOffset += getMaxStubSize();
1090 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1091 if (RelType == ELF::R_PPC64_REL24) {
1092 // A PPC branch relocation will need a stub function if the target is
1093 // an external symbol (Symbol::ST_Unknown) or if the target address
1094 // is not within the signed 24-bits branch address.
1095 SectionEntry &Section = Sections[SectionID];
1096 uint8_t *Target = Section.Address + Offset;
1097 bool RangeOverflow = false;
1098 if (SymType != SymbolRef::ST_Unknown) {
1099 // A function call may points to the .opd entry, so the final symbol
1101 // in calculated based in the relocation values in .opd section.
1102 findOPDEntrySection(Obj, ObjSectionToID, Value);
1103 uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend;
1104 int32_t delta = static_cast<int32_t>(Target - RelocTarget);
1105 // If it is within 24-bits branch range, just set the branch target
1106 if (SignExtend32<24>(delta) == delta) {
1107 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1108 if (Value.SymbolName)
1109 addRelocationForSymbol(RE, Value.SymbolName);
1111 addRelocationForSection(RE, Value.SectionID);
1113 RangeOverflow = true;
1116 if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) {
1117 // It is an external symbol (SymbolRef::ST_Unknown) or within a range
1118 // larger than 24-bits.
1119 StubMap::const_iterator i = Stubs.find(Value);
1120 if (i != Stubs.end()) {
1121 // Symbol function stub already created, just relocate to it
1122 resolveRelocation(Section, Offset,
1123 (uint64_t)Section.Address + i->second, RelType, 0);
1124 DEBUG(dbgs() << " Stub function found\n");
1126 // Create a new stub function.
1127 DEBUG(dbgs() << " Create a new stub function\n");
1128 Stubs[Value] = Section.StubOffset;
1129 uint8_t *StubTargetAddr =
1130 createStubFunction(Section.Address + Section.StubOffset);
1131 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
1132 ELF::R_PPC64_ADDR64, Value.Addend);
1134 // Generates the 64-bits address loads as exemplified in section
1135 // 4.5.1 in PPC64 ELF ABI.
1136 RelocationEntry REhst(SectionID, StubTargetAddr - Section.Address + 2,
1137 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1138 RelocationEntry REhr(SectionID, StubTargetAddr - Section.Address + 6,
1139 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1140 RelocationEntry REh(SectionID, StubTargetAddr - Section.Address + 14,
1141 ELF::R_PPC64_ADDR16_HI, Value.Addend);
1142 RelocationEntry REl(SectionID, StubTargetAddr - Section.Address + 18,
1143 ELF::R_PPC64_ADDR16_LO, Value.Addend);
1145 if (Value.SymbolName) {
1146 addRelocationForSymbol(REhst, Value.SymbolName);
1147 addRelocationForSymbol(REhr, Value.SymbolName);
1148 addRelocationForSymbol(REh, Value.SymbolName);
1149 addRelocationForSymbol(REl, Value.SymbolName);
1151 addRelocationForSection(REhst, Value.SectionID);
1152 addRelocationForSection(REhr, Value.SectionID);
1153 addRelocationForSection(REh, Value.SectionID);
1154 addRelocationForSection(REl, Value.SectionID);
1157 resolveRelocation(Section, Offset,
1158 (uint64_t)Section.Address + Section.StubOffset,
1160 Section.StubOffset += getMaxStubSize();
1162 if (SymType == SymbolRef::ST_Unknown)
1163 // Restore the TOC for external calls
1164 writeInt32BE(Target + 4, 0xE8410028); // ld r2,40(r1)
1167 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1168 // Extra check to avoid relocation againt empty symbols (usually
1169 // the R_PPC64_TOC).
1170 if (SymType != SymbolRef::ST_Unknown && TargetName.empty())
1171 Value.SymbolName = nullptr;
1173 if (Value.SymbolName)
1174 addRelocationForSymbol(RE, Value.SymbolName);
1176 addRelocationForSection(RE, Value.SectionID);
1178 } else if (Arch == Triple::systemz &&
1179 (RelType == ELF::R_390_PLT32DBL || RelType == ELF::R_390_GOTENT)) {
1180 // Create function stubs for both PLT and GOT references, regardless of
1181 // whether the GOT reference is to data or code. The stub contains the
1182 // full address of the symbol, as needed by GOT references, and the
1183 // executable part only adds an overhead of 8 bytes.
1185 // We could try to conserve space by allocating the code and data
1186 // parts of the stub separately. However, as things stand, we allocate
1187 // a stub for every relocation, so using a GOT in JIT code should be
1188 // no less space efficient than using an explicit constant pool.
1189 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1190 SectionEntry &Section = Sections[SectionID];
1192 // Look for an existing stub.
1193 StubMap::const_iterator i = Stubs.find(Value);
1194 uintptr_t StubAddress;
1195 if (i != Stubs.end()) {
1196 StubAddress = uintptr_t(Section.Address) + i->second;
1197 DEBUG(dbgs() << " Stub function found\n");
1199 // Create a new stub function.
1200 DEBUG(dbgs() << " Create a new stub function\n");
1202 uintptr_t BaseAddress = uintptr_t(Section.Address);
1203 uintptr_t StubAlignment = getStubAlignment();
1204 StubAddress = (BaseAddress + Section.StubOffset + StubAlignment - 1) &
1206 unsigned StubOffset = StubAddress - BaseAddress;
1208 Stubs[Value] = StubOffset;
1209 createStubFunction((uint8_t *)StubAddress);
1210 RelocationEntry RE(SectionID, StubOffset + 8, ELF::R_390_64,
1211 Value.Addend - Addend);
1212 if (Value.SymbolName)
1213 addRelocationForSymbol(RE, Value.SymbolName);
1215 addRelocationForSection(RE, Value.SectionID);
1216 Section.StubOffset = StubOffset + getMaxStubSize();
1219 if (RelType == ELF::R_390_GOTENT)
1220 resolveRelocation(Section, Offset, StubAddress + 8, ELF::R_390_PC32DBL,
1223 resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1224 } else if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_PLT32) {
1225 // The way the PLT relocations normally work is that the linker allocates
1227 // PLT and this relocation makes a PC-relative call into the PLT. The PLT
1228 // entry will then jump to an address provided by the GOT. On first call,
1230 // GOT address will point back into PLT code that resolves the symbol. After
1231 // the first call, the GOT entry points to the actual function.
1233 // For local functions we're ignoring all of that here and just replacing
1234 // the PLT32 relocation type with PC32, which will translate the relocation
1235 // into a PC-relative call directly to the function. For external symbols we
1236 // can't be sure the function will be within 2^32 bytes of the call site, so
1237 // we need to create a stub, which calls into the GOT. This case is
1238 // equivalent to the usual PLT implementation except that we use the stub
1239 // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1240 // rather than allocating a PLT section.
1241 if (Value.SymbolName) {
1242 // This is a call to an external function.
1243 // Look for an existing stub.
1244 SectionEntry &Section = Sections[SectionID];
1245 StubMap::const_iterator i = Stubs.find(Value);
1246 uintptr_t StubAddress;
1247 if (i != Stubs.end()) {
1248 StubAddress = uintptr_t(Section.Address) + i->second;
1249 DEBUG(dbgs() << " Stub function found\n");
1251 // Create a new stub function (equivalent to a PLT entry).
1252 DEBUG(dbgs() << " Create a new stub function\n");
1254 uintptr_t BaseAddress = uintptr_t(Section.Address);
1255 uintptr_t StubAlignment = getStubAlignment();
1256 StubAddress = (BaseAddress + Section.StubOffset + StubAlignment - 1) &
1258 unsigned StubOffset = StubAddress - BaseAddress;
1259 Stubs[Value] = StubOffset;
1260 createStubFunction((uint8_t *)StubAddress);
1262 // Create a GOT entry for the external function.
1263 GOTEntries.push_back(Value);
1265 // Make our stub function a relative call to the GOT entry.
1266 RelocationEntry RE(SectionID, StubOffset + 2, ELF::R_X86_64_GOTPCREL,
1268 addRelocationForSymbol(RE, Value.SymbolName);
1270 // Bump our stub offset counter
1271 Section.StubOffset = StubOffset + getMaxStubSize();
1274 // Make the target call a call into the stub table.
1275 resolveRelocation(Section, Offset, StubAddress, ELF::R_X86_64_PC32,
1278 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1280 addRelocationForSection(RE, Value.SectionID);
1283 if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) {
1284 GOTEntries.push_back(Value);
1286 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
1287 if (Value.SymbolName)
1288 addRelocationForSymbol(RE, Value.SymbolName);
1290 addRelocationForSection(RE, Value.SectionID);
1295 void RuntimeDyldELF::updateGOTEntries(StringRef Name, uint64_t Addr) {
1297 SmallVectorImpl<std::pair<SID, GOTRelocations>>::iterator it;
1298 SmallVectorImpl<std::pair<SID, GOTRelocations>>::iterator end = GOTs.end();
1300 for (it = GOTs.begin(); it != end; ++it) {
1301 GOTRelocations &GOTEntries = it->second;
1302 for (int i = 0, e = GOTEntries.size(); i != e; ++i) {
1303 if (GOTEntries[i].SymbolName != nullptr &&
1304 GOTEntries[i].SymbolName == Name) {
1305 GOTEntries[i].Offset = Addr;
1311 size_t RuntimeDyldELF::getGOTEntrySize() {
1312 // We don't use the GOT in all of these cases, but it's essentially free
1313 // to put them all here.
1316 case Triple::x86_64:
1317 case Triple::aarch64:
1319 case Triple::ppc64le:
1320 case Triple::systemz:
1321 Result = sizeof(uint64_t);
1327 case Triple::mipsel:
1328 Result = sizeof(uint32_t);
1331 llvm_unreachable("Unsupported CPU type!");
1336 uint64_t RuntimeDyldELF::findGOTEntry(uint64_t LoadAddress, uint64_t Offset) {
1338 const size_t GOTEntrySize = getGOTEntrySize();
1340 SmallVectorImpl<std::pair<SID, GOTRelocations>>::const_iterator it;
1341 SmallVectorImpl<std::pair<SID, GOTRelocations>>::const_iterator end =
1345 for (it = GOTs.begin(); it != end; ++it) {
1346 SID GOTSectionID = it->first;
1347 const GOTRelocations &GOTEntries = it->second;
1349 // Find the matching entry in our vector.
1350 uint64_t SymbolOffset = 0;
1351 for (int i = 0, e = GOTEntries.size(); i != e; ++i) {
1352 if (!GOTEntries[i].SymbolName) {
1353 if (getSectionLoadAddress(GOTEntries[i].SectionID) == LoadAddress &&
1354 GOTEntries[i].Offset == Offset) {
1356 SymbolOffset = GOTEntries[i].Offset;
1360 // GOT entries for external symbols use the addend as the address when
1361 // the external symbol has been resolved.
1362 if (GOTEntries[i].Offset == LoadAddress) {
1364 // Don't use the Addend here. The relocation handler will use it.
1370 if (GOTIndex != -1) {
1371 if (GOTEntrySize == sizeof(uint64_t)) {
1372 uint64_t *LocalGOTAddr = (uint64_t *)getSectionAddress(GOTSectionID);
1373 // Fill in this entry with the address of the symbol being referenced.
1374 LocalGOTAddr[GOTIndex] = LoadAddress + SymbolOffset;
1376 uint32_t *LocalGOTAddr = (uint32_t *)getSectionAddress(GOTSectionID);
1377 // Fill in this entry with the address of the symbol being referenced.
1378 LocalGOTAddr[GOTIndex] = (uint32_t)(LoadAddress + SymbolOffset);
1381 // Calculate the load address of this entry
1382 return getSectionLoadAddress(GOTSectionID) + (GOTIndex * GOTEntrySize);
1386 assert(GOTIndex != -1 && "Unable to find requested GOT entry.");
1390 void RuntimeDyldELF::finalizeLoad(ObjSectionToIDMap &SectionMap) {
1391 // If necessary, allocate the global offset table
1393 // Allocate the GOT if necessary
1394 size_t numGOTEntries = GOTEntries.size();
1395 if (numGOTEntries != 0) {
1396 // Allocate memory for the section
1397 unsigned SectionID = Sections.size();
1398 size_t TotalSize = numGOTEntries * getGOTEntrySize();
1399 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, getGOTEntrySize(),
1400 SectionID, ".got", false);
1402 report_fatal_error("Unable to allocate memory for GOT!");
1404 GOTs.push_back(std::make_pair(SectionID, GOTEntries));
1405 Sections.push_back(SectionEntry(".got", Addr, TotalSize, 0));
1406 // For now, initialize all GOT entries to zero. We'll fill them in as
1407 // needed when GOT-based relocations are applied.
1408 memset(Addr, 0, TotalSize);
1411 report_fatal_error("Unable to allocate memory for GOT!");
1414 // Look for and record the EH frame section.
1415 ObjSectionToIDMap::iterator i, e;
1416 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1417 const SectionRef &Section = i->first;
1419 Section.getName(Name);
1420 if (Name == ".eh_frame") {
1421 UnregisteredEHFrameSections.push_back(i->second);
1427 bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const {
1428 if (Buffer->getBufferSize() < strlen(ELF::ElfMagic))
1430 return (memcmp(Buffer->getBufferStart(), ELF::ElfMagic,
1431 strlen(ELF::ElfMagic))) == 0;
1434 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile *Obj) const {
1435 return Obj->isELF();