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 #define DEBUG_TYPE "dyld"
15 #include "RuntimeDyldELF.h"
16 #include "JITRegistrar.h"
17 #include "ObjectImageCommon.h"
18 #include "llvm/ADT/IntervalMap.h"
19 #include "llvm/ADT/OwningPtr.h"
20 #include "llvm/ADT/STLExtras.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/ExecutionEngine/ObjectBuffer.h"
24 #include "llvm/ExecutionEngine/ObjectImage.h"
25 #include "llvm/Object/ELFObjectFile.h"
26 #include "llvm/Object/ObjectFile.h"
27 #include "llvm/Support/ELF.h"
28 #include "llvm/Support/MemoryBuffer.h"
31 using namespace llvm::object;
36 error_code check(error_code Err) {
38 report_fatal_error(Err.message());
45 : public ELFObjectFile<ELFT> {
46 LLVM_ELF_IMPORT_TYPES_ELFT(ELFT)
48 typedef Elf_Shdr_Impl<ELFT> Elf_Shdr;
49 typedef Elf_Sym_Impl<ELFT> Elf_Sym;
51 Elf_Rel_Impl<ELFT, false> Elf_Rel;
53 Elf_Rel_Impl<ELFT, true> Elf_Rela;
55 typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr;
57 typedef typename ELFDataTypeTypedefHelper<
58 ELFT>::value_type addr_type;
61 DyldELFObject(MemoryBuffer *Wrapper, error_code &ec);
63 void updateSectionAddress(const SectionRef &Sec, uint64_t Addr);
64 void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr);
66 // Methods for type inquiry through isa, cast and dyn_cast
67 static inline bool classof(const Binary *v) {
68 return (isa<ELFObjectFile<ELFT> >(v)
69 && classof(cast<ELFObjectFile
72 static inline bool classof(
73 const ELFObjectFile<ELFT> *v) {
74 return v->isDyldType();
79 class ELFObjectImage : public ObjectImageCommon {
81 DyldELFObject<ELFT> *DyldObj;
85 ELFObjectImage(ObjectBuffer *Input,
86 DyldELFObject<ELFT> *Obj)
87 : ObjectImageCommon(Input, Obj),
91 virtual ~ELFObjectImage() {
93 deregisterWithDebugger();
96 // Subclasses can override these methods to update the image with loaded
97 // addresses for sections and common symbols
98 virtual void updateSectionAddress(const SectionRef &Sec, uint64_t Addr)
100 DyldObj->updateSectionAddress(Sec, Addr);
103 virtual void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr)
105 DyldObj->updateSymbolAddress(Sym, Addr);
108 virtual void registerWithDebugger()
110 JITRegistrar::getGDBRegistrar().registerObject(*Buffer);
113 virtual void deregisterWithDebugger()
115 JITRegistrar::getGDBRegistrar().deregisterObject(*Buffer);
119 // The MemoryBuffer passed into this constructor is just a wrapper around the
120 // actual memory. Ultimately, the Binary parent class will take ownership of
121 // this MemoryBuffer object but not the underlying memory.
123 DyldELFObject<ELFT>::DyldELFObject(MemoryBuffer *Wrapper, error_code &ec)
124 : ELFObjectFile<ELFT>(Wrapper, ec) {
125 this->isDyldELFObject = true;
129 void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec,
131 DataRefImpl ShdrRef = Sec.getRawDataRefImpl();
132 Elf_Shdr *shdr = const_cast<Elf_Shdr*>(
133 reinterpret_cast<const Elf_Shdr *>(ShdrRef.p));
135 // This assumes the address passed in matches the target address bitness
136 // The template-based type cast handles everything else.
137 shdr->sh_addr = static_cast<addr_type>(Addr);
141 void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef,
144 Elf_Sym *sym = const_cast<Elf_Sym*>(
145 ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl()));
147 // This assumes the address passed in matches the target address bitness
148 // The template-based type cast handles everything else.
149 sym->st_value = static_cast<addr_type>(Addr);
156 void RuntimeDyldELF::registerEHFrames() {
159 for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) {
160 SID EHFrameSID = UnregisteredEHFrameSections[i];
161 uint8_t *EHFrameAddr = Sections[EHFrameSID].Address;
162 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress;
163 size_t EHFrameSize = Sections[EHFrameSID].Size;
164 MemMgr->registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
165 RegisteredEHFrameSections.push_back(EHFrameSID);
167 UnregisteredEHFrameSections.clear();
170 void RuntimeDyldELF::deregisterEHFrames() {
173 for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) {
174 SID EHFrameSID = RegisteredEHFrameSections[i];
175 uint8_t *EHFrameAddr = Sections[EHFrameSID].Address;
176 uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress;
177 size_t EHFrameSize = Sections[EHFrameSID].Size;
178 MemMgr->deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize);
180 RegisteredEHFrameSections.clear();
183 ObjectImage *RuntimeDyldELF::createObjectImageFromFile(object::ObjectFile *ObjFile) {
188 MemoryBuffer* Buffer = MemoryBuffer::getMemBuffer(ObjFile->getData(),
192 if (ObjFile->getBytesInAddress() == 4 && ObjFile->isLittleEndian()) {
193 DyldELFObject<ELFType<support::little, 2, false> > *Obj =
194 new DyldELFObject<ELFType<support::little, 2, false> >(Buffer, ec);
195 return new ELFObjectImage<ELFType<support::little, 2, false> >(NULL, Obj);
197 else if (ObjFile->getBytesInAddress() == 4 && !ObjFile->isLittleEndian()) {
198 DyldELFObject<ELFType<support::big, 2, false> > *Obj =
199 new DyldELFObject<ELFType<support::big, 2, false> >(Buffer, ec);
200 return new ELFObjectImage<ELFType<support::big, 2, false> >(NULL, Obj);
202 else if (ObjFile->getBytesInAddress() == 8 && !ObjFile->isLittleEndian()) {
203 DyldELFObject<ELFType<support::big, 2, true> > *Obj =
204 new DyldELFObject<ELFType<support::big, 2, true> >(Buffer, ec);
205 return new ELFObjectImage<ELFType<support::big, 2, true> >(NULL, Obj);
207 else if (ObjFile->getBytesInAddress() == 8 && ObjFile->isLittleEndian()) {
208 DyldELFObject<ELFType<support::little, 2, true> > *Obj =
209 new DyldELFObject<ELFType<support::little, 2, true> >(Buffer, ec);
210 return new ELFObjectImage<ELFType<support::little, 2, true> >(NULL, Obj);
213 llvm_unreachable("Unexpected ELF format");
216 ObjectImage *RuntimeDyldELF::createObjectImage(ObjectBuffer *Buffer) {
217 if (Buffer->getBufferSize() < ELF::EI_NIDENT)
218 llvm_unreachable("Unexpected ELF object size");
219 std::pair<unsigned char, unsigned char> Ident = std::make_pair(
220 (uint8_t)Buffer->getBufferStart()[ELF::EI_CLASS],
221 (uint8_t)Buffer->getBufferStart()[ELF::EI_DATA]);
224 if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB) {
225 DyldELFObject<ELFType<support::little, 4, false> > *Obj =
226 new DyldELFObject<ELFType<support::little, 4, false> >(
227 Buffer->getMemBuffer(), ec);
228 return new ELFObjectImage<ELFType<support::little, 4, false> >(Buffer, Obj);
230 else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB) {
231 DyldELFObject<ELFType<support::big, 4, false> > *Obj =
232 new DyldELFObject<ELFType<support::big, 4, false> >(
233 Buffer->getMemBuffer(), ec);
234 return new ELFObjectImage<ELFType<support::big, 4, false> >(Buffer, Obj);
236 else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB) {
237 DyldELFObject<ELFType<support::big, 8, true> > *Obj =
238 new DyldELFObject<ELFType<support::big, 8, true> >(
239 Buffer->getMemBuffer(), ec);
240 return new ELFObjectImage<ELFType<support::big, 8, true> >(Buffer, Obj);
242 else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) {
243 DyldELFObject<ELFType<support::little, 8, true> > *Obj =
244 new DyldELFObject<ELFType<support::little, 8, true> >(
245 Buffer->getMemBuffer(), ec);
246 return new ELFObjectImage<ELFType<support::little, 8, true> >(Buffer, Obj);
249 llvm_unreachable("Unexpected ELF format");
252 RuntimeDyldELF::~RuntimeDyldELF() {
255 void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section,
260 uint64_t SymOffset) {
263 llvm_unreachable("Relocation type not implemented yet!");
265 case ELF::R_X86_64_64: {
266 uint64_t *Target = reinterpret_cast<uint64_t*>(Section.Address + Offset);
267 *Target = Value + Addend;
268 DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend))
269 << " at " << format("%p\n",Target));
272 case ELF::R_X86_64_32:
273 case ELF::R_X86_64_32S: {
275 assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) ||
276 (Type == ELF::R_X86_64_32S &&
277 ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN)));
278 uint32_t TruncatedAddr = (Value & 0xFFFFFFFF);
279 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
280 *Target = TruncatedAddr;
281 DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr)
282 << " at " << format("%p\n",Target));
285 case ELF::R_X86_64_GOTPCREL: {
286 // findGOTEntry returns the 'G + GOT' part of the relocation calculation
287 // based on the load/target address of the GOT (not the current/local addr).
288 uint64_t GOTAddr = findGOTEntry(Value, SymOffset);
289 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
290 uint64_t FinalAddress = Section.LoadAddress + Offset;
291 // The processRelocationRef method combines the symbol offset and the addend
292 // and in most cases that's what we want. For this relocation type, we need
293 // the raw addend, so we subtract the symbol offset to get it.
294 int64_t RealOffset = GOTAddr + Addend - SymOffset - FinalAddress;
295 assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);
296 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
297 *Target = TruncOffset;
300 case ELF::R_X86_64_PC32: {
301 // Get the placeholder value from the generated object since
302 // a previous relocation attempt may have overwritten the loaded version
303 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
305 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
306 uint64_t FinalAddress = Section.LoadAddress + Offset;
307 int64_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
308 assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN);
309 int32_t TruncOffset = (RealOffset & 0xFFFFFFFF);
310 *Target = TruncOffset;
313 case ELF::R_X86_64_PC64: {
314 // Get the placeholder value from the generated object since
315 // a previous relocation attempt may have overwritten the loaded version
316 uint64_t *Placeholder = reinterpret_cast<uint64_t*>(Section.ObjAddress
318 uint64_t *Target = reinterpret_cast<uint64_t*>(Section.Address + Offset);
319 uint64_t FinalAddress = Section.LoadAddress + Offset;
320 *Target = *Placeholder + Value + Addend - FinalAddress;
326 void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section,
332 case ELF::R_386_32: {
333 // Get the placeholder value from the generated object since
334 // a previous relocation attempt may have overwritten the loaded version
335 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
337 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
338 *Target = *Placeholder + Value + Addend;
341 case ELF::R_386_PC32: {
342 // Get the placeholder value from the generated object since
343 // a previous relocation attempt may have overwritten the loaded version
344 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress
346 uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset);
347 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
348 uint32_t RealOffset = *Placeholder + Value + Addend - FinalAddress;
349 *Target = RealOffset;
353 // There are other relocation types, but it appears these are the
354 // only ones currently used by the LLVM ELF object writer
355 llvm_unreachable("Relocation type not implemented yet!");
360 void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section,
365 uint32_t *TargetPtr = reinterpret_cast<uint32_t*>(Section.Address + Offset);
366 uint64_t FinalAddress = Section.LoadAddress + Offset;
368 DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x"
369 << format("%llx", Section.Address + Offset)
370 << " FinalAddress: 0x" << format("%llx",FinalAddress)
371 << " Value: 0x" << format("%llx",Value)
372 << " Type: 0x" << format("%x",Type)
373 << " Addend: 0x" << format("%llx",Addend)
378 llvm_unreachable("Relocation type not implemented yet!");
380 case ELF::R_AARCH64_ABS64: {
381 uint64_t *TargetPtr = reinterpret_cast<uint64_t*>(Section.Address + Offset);
382 *TargetPtr = Value + Addend;
385 case ELF::R_AARCH64_PREL32: {
386 uint64_t Result = Value + Addend - FinalAddress;
387 assert(static_cast<int64_t>(Result) >= INT32_MIN &&
388 static_cast<int64_t>(Result) <= UINT32_MAX);
389 *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU);
392 case ELF::R_AARCH64_CALL26: // fallthrough
393 case ELF::R_AARCH64_JUMP26: {
394 // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the
396 uint64_t BranchImm = Value + Addend - FinalAddress;
398 // "Check that -2^27 <= result < 2^27".
399 assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) &&
400 static_cast<int64_t>(BranchImm) < (1LL << 27));
402 // AArch64 code is emitted with .rela relocations. The data already in any
403 // bits affected by the relocation on entry is garbage.
404 *TargetPtr &= 0xfc000000U;
405 // Immediate goes in bits 25:0 of B and BL.
406 *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2;
409 case ELF::R_AARCH64_MOVW_UABS_G3: {
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 >> (48 - 5);
417 // Shift must be "lsl #48", in bits 22:21
418 assert((*TargetPtr >> 21 & 0x3) == 3 && "invalid shift for relocation");
421 case ELF::R_AARCH64_MOVW_UABS_G2_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 & 0xffff00000000ULL) >> (32 - 5));
429 // Shift must be "lsl #32", in bits 22:21
430 assert((*TargetPtr >> 21 & 0x3) == 2 && "invalid shift for relocation");
433 case ELF::R_AARCH64_MOVW_UABS_G1_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 & 0xffff0000U) >> (16 - 5));
441 // Shift must be "lsl #16", in bits 22:2
442 assert((*TargetPtr >> 21 & 0x3) == 1 && "invalid shift for relocation");
445 case ELF::R_AARCH64_MOVW_UABS_G0_NC: {
446 uint64_t Result = Value + Addend;
448 // AArch64 code is emitted with .rela relocations. The data already in any
449 // bits affected by the relocation on entry is garbage.
450 *TargetPtr &= 0xffe0001fU;
451 // Immediate goes in bits 20:5 of MOVZ/MOVK instruction
452 *TargetPtr |= ((Result & 0xffffU) << 5);
453 // Shift must be "lsl #0", in bits 22:21.
454 assert((*TargetPtr >> 21 & 0x3) == 0 && "invalid shift for relocation");
460 void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section,
465 // TODO: Add Thumb relocations.
466 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress +
468 uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
469 uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF);
472 DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: "
473 << Section.Address + Offset
474 << " FinalAddress: " << format("%p",FinalAddress)
475 << " Value: " << format("%x",Value)
476 << " Type: " << format("%x",Type)
477 << " Addend: " << format("%x",Addend)
482 llvm_unreachable("Not implemented relocation type!");
484 case ELF::R_ARM_NONE:
486 // Write a 32bit value to relocation address, taking into account the
487 // implicit addend encoded in the target.
488 case ELF::R_ARM_PREL31:
489 case ELF::R_ARM_TARGET1:
490 case ELF::R_ARM_ABS32:
491 *TargetPtr = *Placeholder + Value;
493 // Write first 16 bit of 32 bit value to the mov instruction.
494 // Last 4 bit should be shifted.
495 case ELF::R_ARM_MOVW_ABS_NC:
496 // We are not expecting any other addend in the relocation address.
497 // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2
498 // non-contiguous fields.
499 assert((*Placeholder & 0x000F0FFF) == 0);
500 Value = Value & 0xFFFF;
501 *TargetPtr = *Placeholder | (Value & 0xFFF);
502 *TargetPtr |= ((Value >> 12) & 0xF) << 16;
504 // Write last 16 bit of 32 bit value to the mov instruction.
505 // Last 4 bit should be shifted.
506 case ELF::R_ARM_MOVT_ABS:
507 // We are not expecting any other addend in the relocation address.
508 // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC.
509 assert((*Placeholder & 0x000F0FFF) == 0);
511 Value = (Value >> 16) & 0xFFFF;
512 *TargetPtr = *Placeholder | (Value & 0xFFF);
513 *TargetPtr |= ((Value >> 12) & 0xF) << 16;
515 // Write 24 bit relative value to the branch instruction.
516 case ELF::R_ARM_PC24 : // Fall through.
517 case ELF::R_ARM_CALL : // Fall through.
518 case ELF::R_ARM_JUMP24: {
519 int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8);
520 RelValue = (RelValue & 0x03FFFFFC) >> 2;
521 assert((*TargetPtr & 0xFFFFFF) == 0xFFFFFE);
522 *TargetPtr &= 0xFF000000;
523 *TargetPtr |= RelValue;
526 case ELF::R_ARM_PRIVATE_0:
527 // This relocation is reserved by the ARM ELF ABI for internal use. We
528 // appropriate it here to act as an R_ARM_ABS32 without any addend for use
529 // in the stubs created during JIT (which can't put an addend into the
530 // original object file).
536 void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section,
541 uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress +
543 uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset);
546 DEBUG(dbgs() << "resolveMipselocation, LocalAddress: "
547 << Section.Address + Offset
549 << format("%p",Section.LoadAddress + Offset)
550 << " Value: " << format("%x",Value)
551 << " Type: " << format("%x",Type)
552 << " Addend: " << format("%x",Addend)
557 llvm_unreachable("Not implemented relocation type!");
560 *TargetPtr = Value + (*Placeholder);
563 *TargetPtr = ((*Placeholder) & 0xfc000000) | (( Value & 0x0fffffff) >> 2);
565 case ELF::R_MIPS_HI16:
566 // Get the higher 16-bits. Also add 1 if bit 15 is 1.
567 Value += ((*Placeholder) & 0x0000ffff) << 16;
568 *TargetPtr = ((*Placeholder) & 0xffff0000) |
569 (((Value + 0x8000) >> 16) & 0xffff);
571 case ELF::R_MIPS_LO16:
572 Value += ((*Placeholder) & 0x0000ffff);
573 *TargetPtr = ((*Placeholder) & 0xffff0000) | (Value & 0xffff);
575 case ELF::R_MIPS_UNUSED1:
576 // Similar to ELF::R_ARM_PRIVATE_0, R_MIPS_UNUSED1 and R_MIPS_UNUSED2
577 // are used for internal JIT purpose. These relocations are similar to
578 // R_MIPS_HI16 and R_MIPS_LO16, but they do not take any addend into
580 *TargetPtr = ((*TargetPtr) & 0xffff0000) |
581 (((Value + 0x8000) >> 16) & 0xffff);
583 case ELF::R_MIPS_UNUSED2:
584 *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff);
589 // Return the .TOC. section address to R_PPC64_TOC relocations.
590 uint64_t RuntimeDyldELF::findPPC64TOC() const {
591 // The TOC consists of sections .got, .toc, .tocbss, .plt in that
592 // order. The TOC starts where the first of these sections starts.
593 SectionList::const_iterator it = Sections.begin();
594 SectionList::const_iterator ite = Sections.end();
595 for (; it != ite; ++it) {
596 if (it->Name == ".got" ||
597 it->Name == ".toc" ||
598 it->Name == ".tocbss" ||
603 // This may happen for
604 // * references to TOC base base (sym@toc, .odp relocation) without
606 // In this case just use the first section (which is usually
607 // the .odp) since the code won't reference the .toc base
609 it = Sections.begin();
612 // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000
613 // thus permitting a full 64 Kbytes segment.
614 return it->LoadAddress + 0x8000;
617 // Returns the sections and offset associated with the ODP entry referenced
619 void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj,
620 ObjSectionToIDMap &LocalSections,
621 RelocationValueRef &Rel) {
622 // Get the ELF symbol value (st_value) to compare with Relocation offset in
624 for (section_iterator si = Obj.begin_sections(), se = Obj.end_sections();
626 section_iterator RelSecI = si->getRelocatedSection();
627 if (RelSecI == Obj.end_sections())
630 StringRef RelSectionName;
631 check(RelSecI->getName(RelSectionName));
632 if (RelSectionName != ".opd")
635 for (relocation_iterator i = si->relocation_begin(),
636 e = si->relocation_end(); i != e;) {
637 // The R_PPC64_ADDR64 relocation indicates the first field
640 check(i->getType(TypeFunc));
641 if (TypeFunc != ELF::R_PPC64_ADDR64) {
646 uint64_t TargetSymbolOffset;
647 symbol_iterator TargetSymbol = i->getSymbol();
648 check(i->getOffset(TargetSymbolOffset));
650 check(getELFRelocationAddend(*i, Addend));
656 // Just check if following relocation is a R_PPC64_TOC
658 check(i->getType(TypeTOC));
659 if (TypeTOC != ELF::R_PPC64_TOC)
662 // Finally compares the Symbol value and the target symbol offset
663 // to check if this .opd entry refers to the symbol the relocation
665 if (Rel.Addend != (int64_t)TargetSymbolOffset)
668 section_iterator tsi(Obj.end_sections());
669 check(TargetSymbol->getSection(tsi));
670 Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections);
671 Rel.Addend = (intptr_t)Addend;
675 llvm_unreachable("Attempting to get address of ODP entry!");
678 // Relocation masks following the #lo(value), #hi(value), #higher(value),
679 // and #highest(value) macros defined in section 4.5.1. Relocation Types
680 // in PPC-elf64abi document.
683 uint16_t applyPPClo (uint64_t value)
685 return value & 0xffff;
689 uint16_t applyPPChi (uint64_t value)
691 return (value >> 16) & 0xffff;
695 uint16_t applyPPChigher (uint64_t value)
697 return (value >> 32) & 0xffff;
701 uint16_t applyPPChighest (uint64_t value)
703 return (value >> 48) & 0xffff;
706 void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section,
711 uint8_t* LocalAddress = Section.Address + Offset;
714 llvm_unreachable("Relocation type not implemented yet!");
716 case ELF::R_PPC64_ADDR16_LO :
717 writeInt16BE(LocalAddress, applyPPClo (Value + Addend));
719 case ELF::R_PPC64_ADDR16_HI :
720 writeInt16BE(LocalAddress, applyPPChi (Value + Addend));
722 case ELF::R_PPC64_ADDR16_HIGHER :
723 writeInt16BE(LocalAddress, applyPPChigher (Value + Addend));
725 case ELF::R_PPC64_ADDR16_HIGHEST :
726 writeInt16BE(LocalAddress, applyPPChighest (Value + Addend));
728 case ELF::R_PPC64_ADDR14 : {
729 assert(((Value + Addend) & 3) == 0);
730 // Preserve the AA/LK bits in the branch instruction
731 uint8_t aalk = *(LocalAddress+3);
732 writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc));
734 case ELF::R_PPC64_ADDR32 : {
735 int32_t Result = static_cast<int32_t>(Value + Addend);
736 if (SignExtend32<32>(Result) != Result)
737 llvm_unreachable("Relocation R_PPC64_ADDR32 overflow");
738 writeInt32BE(LocalAddress, Result);
740 case ELF::R_PPC64_REL24 : {
741 uint64_t FinalAddress = (Section.LoadAddress + Offset);
742 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
743 if (SignExtend32<24>(delta) != delta)
744 llvm_unreachable("Relocation R_PPC64_REL24 overflow");
745 // Generates a 'bl <address>' instruction
746 writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC));
748 case ELF::R_PPC64_REL32 : {
749 uint64_t FinalAddress = (Section.LoadAddress + Offset);
750 int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend);
751 if (SignExtend32<32>(delta) != delta)
752 llvm_unreachable("Relocation R_PPC64_REL32 overflow");
753 writeInt32BE(LocalAddress, delta);
755 case ELF::R_PPC64_REL64: {
756 uint64_t FinalAddress = (Section.LoadAddress + Offset);
757 uint64_t Delta = Value - FinalAddress + Addend;
758 writeInt64BE(LocalAddress, Delta);
760 case ELF::R_PPC64_ADDR64 :
761 writeInt64BE(LocalAddress, Value + Addend);
763 case ELF::R_PPC64_TOC :
764 writeInt64BE(LocalAddress, findPPC64TOC());
766 case ELF::R_PPC64_TOC16 : {
767 uint64_t TOCStart = findPPC64TOC();
768 Value = applyPPClo((Value + Addend) - TOCStart);
769 writeInt16BE(LocalAddress, applyPPClo(Value));
771 case ELF::R_PPC64_TOC16_DS : {
772 uint64_t TOCStart = findPPC64TOC();
773 Value = ((Value + Addend) - TOCStart);
774 writeInt16BE(LocalAddress, applyPPClo(Value));
779 void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section,
784 uint8_t *LocalAddress = Section.Address + Offset;
787 llvm_unreachable("Relocation type not implemented yet!");
789 case ELF::R_390_PC16DBL:
790 case ELF::R_390_PLT16DBL: {
791 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
792 assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow");
793 writeInt16BE(LocalAddress, Delta / 2);
796 case ELF::R_390_PC32DBL:
797 case ELF::R_390_PLT32DBL: {
798 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
799 assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow");
800 writeInt32BE(LocalAddress, Delta / 2);
803 case ELF::R_390_PC32: {
804 int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset);
805 assert(int32_t(Delta) == Delta && "R_390_PC32 overflow");
806 writeInt32BE(LocalAddress, Delta);
810 writeInt64BE(LocalAddress, Value + Addend);
815 // The target location for the relocation is described by RE.SectionID and
816 // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each
817 // SectionEntry has three members describing its location.
818 // SectionEntry::Address is the address at which the section has been loaded
819 // into memory in the current (host) process. SectionEntry::LoadAddress is the
820 // address that the section will have in the target process.
821 // SectionEntry::ObjAddress is the address of the bits for this section in the
822 // original emitted object image (also in the current address space).
824 // Relocations will be applied as if the section were loaded at
825 // SectionEntry::LoadAddress, but they will be applied at an address based
826 // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to
827 // Target memory contents if they are required for value calculations.
829 // The Value parameter here is the load address of the symbol for the
830 // relocation to be applied. For relocations which refer to symbols in the
831 // current object Value will be the LoadAddress of the section in which
832 // the symbol resides (RE.Addend provides additional information about the
833 // symbol location). For external symbols, Value will be the address of the
834 // symbol in the target address space.
835 void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE,
837 const SectionEntry &Section = Sections[RE.SectionID];
838 return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend,
842 void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section,
847 uint64_t SymOffset) {
850 resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset);
853 resolveX86Relocation(Section, Offset,
854 (uint32_t)(Value & 0xffffffffL), Type,
855 (uint32_t)(Addend & 0xffffffffL));
857 case Triple::aarch64:
858 resolveAArch64Relocation(Section, Offset, Value, Type, Addend);
860 case Triple::arm: // Fall through.
862 resolveARMRelocation(Section, Offset,
863 (uint32_t)(Value & 0xffffffffL), Type,
864 (uint32_t)(Addend & 0xffffffffL));
866 case Triple::mips: // Fall through.
868 resolveMIPSRelocation(Section, Offset,
869 (uint32_t)(Value & 0xffffffffL), Type,
870 (uint32_t)(Addend & 0xffffffffL));
872 case Triple::ppc64: // Fall through.
873 case Triple::ppc64le:
874 resolvePPC64Relocation(Section, Offset, Value, Type, Addend);
876 case Triple::systemz:
877 resolveSystemZRelocation(Section, Offset, Value, Type, Addend);
879 default: llvm_unreachable("Unsupported CPU type!");
883 void RuntimeDyldELF::processRelocationRef(unsigned SectionID,
886 ObjSectionToIDMap &ObjSectionToID,
887 const SymbolTableMap &Symbols,
890 Check(RelI.getType(RelType));
892 Check(getELFRelocationAddend(RelI, Addend));
893 symbol_iterator Symbol = RelI.getSymbol();
895 // Obtain the symbol name which is referenced in the relocation
896 StringRef TargetName;
897 if (Symbol != Obj.end_symbols())
898 Symbol->getName(TargetName);
899 DEBUG(dbgs() << "\t\tRelType: " << RelType
900 << " Addend: " << Addend
901 << " TargetName: " << TargetName
903 RelocationValueRef Value;
904 // First search for the symbol in the local symbol table
905 SymbolTableMap::const_iterator lsi = Symbols.end();
906 SymbolRef::Type SymType = SymbolRef::ST_Unknown;
907 if (Symbol != Obj.end_symbols()) {
908 lsi = Symbols.find(TargetName.data());
909 Symbol->getType(SymType);
911 if (lsi != Symbols.end()) {
912 Value.SectionID = lsi->second.first;
913 Value.Offset = lsi->second.second;
914 Value.Addend = lsi->second.second + Addend;
916 // Search for the symbol in the global symbol table
917 SymbolTableMap::const_iterator gsi = GlobalSymbolTable.end();
918 if (Symbol != Obj.end_symbols())
919 gsi = GlobalSymbolTable.find(TargetName.data());
920 if (gsi != GlobalSymbolTable.end()) {
921 Value.SectionID = gsi->second.first;
922 Value.Offset = gsi->second.second;
923 Value.Addend = gsi->second.second + Addend;
926 case SymbolRef::ST_Debug: {
927 // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously
928 // and can be changed by another developers. Maybe best way is add
929 // a new symbol type ST_Section to SymbolRef and use it.
930 section_iterator si(Obj.end_sections());
931 Symbol->getSection(si);
932 if (si == Obj.end_sections())
933 llvm_unreachable("Symbol section not found, bad object file format!");
934 DEBUG(dbgs() << "\t\tThis is section symbol\n");
935 // Default to 'true' in case isText fails (though it never does).
938 Value.SectionID = findOrEmitSection(Obj,
942 Value.Addend = Addend;
945 case SymbolRef::ST_Data:
946 case SymbolRef::ST_Unknown: {
947 Value.SymbolName = TargetName.data();
948 Value.Addend = Addend;
950 // Absolute relocations will have a zero symbol ID (STN_UNDEF), which
951 // will manifest here as a NULL symbol name.
952 // We can set this as a valid (but empty) symbol name, and rely
953 // on addRelocationForSymbol to handle this.
954 if (!Value.SymbolName)
955 Value.SymbolName = "";
959 llvm_unreachable("Unresolved symbol type!");
965 Check(RelI.getOffset(Offset));
967 DEBUG(dbgs() << "\t\tSectionID: " << SectionID
968 << " Offset: " << Offset
970 if (Arch == Triple::aarch64 &&
971 (RelType == ELF::R_AARCH64_CALL26 ||
972 RelType == ELF::R_AARCH64_JUMP26)) {
973 // This is an AArch64 branch relocation, need to use a stub function.
974 DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation.");
975 SectionEntry &Section = Sections[SectionID];
977 // Look for an existing stub.
978 StubMap::const_iterator i = Stubs.find(Value);
979 if (i != Stubs.end()) {
980 resolveRelocation(Section, Offset,
981 (uint64_t)Section.Address + i->second, RelType, 0);
982 DEBUG(dbgs() << " Stub function found\n");
984 // Create a new stub function.
985 DEBUG(dbgs() << " Create a new stub function\n");
986 Stubs[Value] = Section.StubOffset;
987 uint8_t *StubTargetAddr = createStubFunction(Section.Address +
990 RelocationEntry REmovz_g3(SectionID,
991 StubTargetAddr - Section.Address,
992 ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend);
993 RelocationEntry REmovk_g2(SectionID,
994 StubTargetAddr - Section.Address + 4,
995 ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend);
996 RelocationEntry REmovk_g1(SectionID,
997 StubTargetAddr - Section.Address + 8,
998 ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend);
999 RelocationEntry REmovk_g0(SectionID,
1000 StubTargetAddr - Section.Address + 12,
1001 ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend);
1003 if (Value.SymbolName) {
1004 addRelocationForSymbol(REmovz_g3, Value.SymbolName);
1005 addRelocationForSymbol(REmovk_g2, Value.SymbolName);
1006 addRelocationForSymbol(REmovk_g1, Value.SymbolName);
1007 addRelocationForSymbol(REmovk_g0, Value.SymbolName);
1009 addRelocationForSection(REmovz_g3, Value.SectionID);
1010 addRelocationForSection(REmovk_g2, Value.SectionID);
1011 addRelocationForSection(REmovk_g1, Value.SectionID);
1012 addRelocationForSection(REmovk_g0, Value.SectionID);
1014 resolveRelocation(Section, Offset,
1015 (uint64_t)Section.Address + Section.StubOffset,
1017 Section.StubOffset += getMaxStubSize();
1019 } else if (Arch == Triple::arm &&
1020 (RelType == ELF::R_ARM_PC24 ||
1021 RelType == ELF::R_ARM_CALL ||
1022 RelType == ELF::R_ARM_JUMP24)) {
1023 // This is an ARM branch relocation, need to use a stub function.
1024 DEBUG(dbgs() << "\t\tThis is an ARM branch relocation.");
1025 SectionEntry &Section = Sections[SectionID];
1027 // Look for an existing stub.
1028 StubMap::const_iterator i = Stubs.find(Value);
1029 if (i != Stubs.end()) {
1030 resolveRelocation(Section, Offset,
1031 (uint64_t)Section.Address + i->second, RelType, 0);
1032 DEBUG(dbgs() << " Stub function found\n");
1034 // Create a new stub function.
1035 DEBUG(dbgs() << " Create a new stub function\n");
1036 Stubs[Value] = Section.StubOffset;
1037 uint8_t *StubTargetAddr = createStubFunction(Section.Address +
1038 Section.StubOffset);
1039 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
1040 ELF::R_ARM_PRIVATE_0, Value.Addend);
1041 if (Value.SymbolName)
1042 addRelocationForSymbol(RE, Value.SymbolName);
1044 addRelocationForSection(RE, Value.SectionID);
1046 resolveRelocation(Section, Offset,
1047 (uint64_t)Section.Address + Section.StubOffset,
1049 Section.StubOffset += getMaxStubSize();
1051 } else if ((Arch == Triple::mipsel || Arch == Triple::mips) &&
1052 RelType == ELF::R_MIPS_26) {
1053 // This is an Mips branch relocation, need to use a stub function.
1054 DEBUG(dbgs() << "\t\tThis is a Mips branch relocation.");
1055 SectionEntry &Section = Sections[SectionID];
1056 uint8_t *Target = Section.Address + Offset;
1057 uint32_t *TargetAddress = (uint32_t *)Target;
1059 // Extract the addend from the instruction.
1060 uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2;
1062 Value.Addend += Addend;
1064 // Look up for existing stub.
1065 StubMap::const_iterator i = Stubs.find(Value);
1066 if (i != Stubs.end()) {
1067 RelocationEntry RE(SectionID, Offset, RelType, i->second);
1068 addRelocationForSection(RE, SectionID);
1069 DEBUG(dbgs() << " Stub function found\n");
1071 // Create a new stub function.
1072 DEBUG(dbgs() << " Create a new stub function\n");
1073 Stubs[Value] = Section.StubOffset;
1074 uint8_t *StubTargetAddr = createStubFunction(Section.Address +
1075 Section.StubOffset);
1077 // Creating Hi and Lo relocations for the filled stub instructions.
1078 RelocationEntry REHi(SectionID,
1079 StubTargetAddr - Section.Address,
1080 ELF::R_MIPS_UNUSED1, Value.Addend);
1081 RelocationEntry RELo(SectionID,
1082 StubTargetAddr - Section.Address + 4,
1083 ELF::R_MIPS_UNUSED2, Value.Addend);
1085 if (Value.SymbolName) {
1086 addRelocationForSymbol(REHi, Value.SymbolName);
1087 addRelocationForSymbol(RELo, Value.SymbolName);
1089 addRelocationForSection(REHi, Value.SectionID);
1090 addRelocationForSection(RELo, Value.SectionID);
1093 RelocationEntry RE(SectionID, Offset, RelType, Section.StubOffset);
1094 addRelocationForSection(RE, SectionID);
1095 Section.StubOffset += getMaxStubSize();
1097 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
1098 if (RelType == ELF::R_PPC64_REL24) {
1099 // A PPC branch relocation will need a stub function if the target is
1100 // an external symbol (Symbol::ST_Unknown) or if the target address
1101 // is not within the signed 24-bits branch address.
1102 SectionEntry &Section = Sections[SectionID];
1103 uint8_t *Target = Section.Address + Offset;
1104 bool RangeOverflow = false;
1105 if (SymType != SymbolRef::ST_Unknown) {
1106 // A function call may points to the .opd entry, so the final symbol value
1107 // in calculated based in the relocation values in .opd section.
1108 findOPDEntrySection(Obj, ObjSectionToID, Value);
1109 uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend;
1110 int32_t delta = static_cast<int32_t>(Target - RelocTarget);
1111 // If it is within 24-bits branch range, just set the branch target
1112 if (SignExtend32<24>(delta) == delta) {
1113 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1114 if (Value.SymbolName)
1115 addRelocationForSymbol(RE, Value.SymbolName);
1117 addRelocationForSection(RE, Value.SectionID);
1119 RangeOverflow = true;
1122 if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) {
1123 // It is an external symbol (SymbolRef::ST_Unknown) or within a range
1124 // larger than 24-bits.
1125 StubMap::const_iterator i = Stubs.find(Value);
1126 if (i != Stubs.end()) {
1127 // Symbol function stub already created, just relocate to it
1128 resolveRelocation(Section, Offset,
1129 (uint64_t)Section.Address + i->second, RelType, 0);
1130 DEBUG(dbgs() << " Stub function found\n");
1132 // Create a new stub function.
1133 DEBUG(dbgs() << " Create a new stub function\n");
1134 Stubs[Value] = Section.StubOffset;
1135 uint8_t *StubTargetAddr = createStubFunction(Section.Address +
1136 Section.StubOffset);
1137 RelocationEntry RE(SectionID, StubTargetAddr - Section.Address,
1138 ELF::R_PPC64_ADDR64, Value.Addend);
1140 // Generates the 64-bits address loads as exemplified in section
1141 // 4.5.1 in PPC64 ELF ABI.
1142 RelocationEntry REhst(SectionID,
1143 StubTargetAddr - Section.Address + 2,
1144 ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend);
1145 RelocationEntry REhr(SectionID,
1146 StubTargetAddr - Section.Address + 6,
1147 ELF::R_PPC64_ADDR16_HIGHER, Value.Addend);
1148 RelocationEntry REh(SectionID,
1149 StubTargetAddr - Section.Address + 14,
1150 ELF::R_PPC64_ADDR16_HI, Value.Addend);
1151 RelocationEntry REl(SectionID,
1152 StubTargetAddr - Section.Address + 18,
1153 ELF::R_PPC64_ADDR16_LO, Value.Addend);
1155 if (Value.SymbolName) {
1156 addRelocationForSymbol(REhst, Value.SymbolName);
1157 addRelocationForSymbol(REhr, Value.SymbolName);
1158 addRelocationForSymbol(REh, Value.SymbolName);
1159 addRelocationForSymbol(REl, Value.SymbolName);
1161 addRelocationForSection(REhst, Value.SectionID);
1162 addRelocationForSection(REhr, Value.SectionID);
1163 addRelocationForSection(REh, Value.SectionID);
1164 addRelocationForSection(REl, Value.SectionID);
1167 resolveRelocation(Section, Offset,
1168 (uint64_t)Section.Address + Section.StubOffset,
1170 if (SymType == SymbolRef::ST_Unknown)
1171 // Restore the TOC for external calls
1172 writeInt32BE(Target+4, 0xE8410028); // ld r2,40(r1)
1173 Section.StubOffset += getMaxStubSize();
1177 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend);
1178 // Extra check to avoid relocation againt empty symbols (usually
1179 // the R_PPC64_TOC).
1180 if (SymType != SymbolRef::ST_Unknown && TargetName.empty())
1181 Value.SymbolName = NULL;
1183 if (Value.SymbolName)
1184 addRelocationForSymbol(RE, Value.SymbolName);
1186 addRelocationForSection(RE, Value.SectionID);
1188 } else if (Arch == Triple::systemz &&
1189 (RelType == ELF::R_390_PLT32DBL ||
1190 RelType == ELF::R_390_GOTENT)) {
1191 // Create function stubs for both PLT and GOT references, regardless of
1192 // whether the GOT reference is to data or code. The stub contains the
1193 // full address of the symbol, as needed by GOT references, and the
1194 // executable part only adds an overhead of 8 bytes.
1196 // We could try to conserve space by allocating the code and data
1197 // parts of the stub separately. However, as things stand, we allocate
1198 // a stub for every relocation, so using a GOT in JIT code should be
1199 // no less space efficient than using an explicit constant pool.
1200 DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation.");
1201 SectionEntry &Section = Sections[SectionID];
1203 // Look for an existing stub.
1204 StubMap::const_iterator i = Stubs.find(Value);
1205 uintptr_t StubAddress;
1206 if (i != Stubs.end()) {
1207 StubAddress = uintptr_t(Section.Address) + i->second;
1208 DEBUG(dbgs() << " Stub function found\n");
1210 // Create a new stub function.
1211 DEBUG(dbgs() << " Create a new stub function\n");
1213 uintptr_t BaseAddress = uintptr_t(Section.Address);
1214 uintptr_t StubAlignment = getStubAlignment();
1215 StubAddress = (BaseAddress + Section.StubOffset +
1216 StubAlignment - 1) & -StubAlignment;
1217 unsigned StubOffset = StubAddress - BaseAddress;
1219 Stubs[Value] = StubOffset;
1220 createStubFunction((uint8_t *)StubAddress);
1221 RelocationEntry RE(SectionID, StubOffset + 8,
1222 ELF::R_390_64, Value.Addend - Addend);
1223 if (Value.SymbolName)
1224 addRelocationForSymbol(RE, Value.SymbolName);
1226 addRelocationForSection(RE, Value.SectionID);
1227 Section.StubOffset = StubOffset + getMaxStubSize();
1230 if (RelType == ELF::R_390_GOTENT)
1231 resolveRelocation(Section, Offset, StubAddress + 8,
1232 ELF::R_390_PC32DBL, Addend);
1234 resolveRelocation(Section, Offset, StubAddress, RelType, Addend);
1235 } else if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_PLT32) {
1236 // The way the PLT relocations normally work is that the linker allocates the
1237 // PLT and this relocation makes a PC-relative call into the PLT. The PLT
1238 // entry will then jump to an address provided by the GOT. On first call, the
1239 // GOT address will point back into PLT code that resolves the symbol. After
1240 // the first call, the GOT entry points to the actual function.
1242 // For local functions we're ignoring all of that here and just replacing
1243 // the PLT32 relocation type with PC32, which will translate the relocation
1244 // into a PC-relative call directly to the function. For external symbols we
1245 // can't be sure the function will be within 2^32 bytes of the call site, so
1246 // we need to create a stub, which calls into the GOT. This case is
1247 // equivalent to the usual PLT implementation except that we use the stub
1248 // mechanism in RuntimeDyld (which puts stubs at the end of the section)
1249 // rather than allocating a PLT section.
1250 if (Value.SymbolName) {
1251 // This is a call to an external function.
1252 // Look for an existing stub.
1253 SectionEntry &Section = Sections[SectionID];
1254 StubMap::const_iterator i = Stubs.find(Value);
1255 uintptr_t StubAddress;
1256 if (i != Stubs.end()) {
1257 StubAddress = uintptr_t(Section.Address) + i->second;
1258 DEBUG(dbgs() << " Stub function found\n");
1260 // Create a new stub function (equivalent to a PLT entry).
1261 DEBUG(dbgs() << " Create a new stub function\n");
1263 uintptr_t BaseAddress = uintptr_t(Section.Address);
1264 uintptr_t StubAlignment = getStubAlignment();
1265 StubAddress = (BaseAddress + Section.StubOffset +
1266 StubAlignment - 1) & -StubAlignment;
1267 unsigned StubOffset = StubAddress - BaseAddress;
1268 Stubs[Value] = StubOffset;
1269 createStubFunction((uint8_t *)StubAddress);
1271 // Create a GOT entry for the external function.
1272 GOTEntries.push_back(Value);
1274 // Make our stub function a relative call to the GOT entry.
1275 RelocationEntry RE(SectionID, StubOffset + 2,
1276 ELF::R_X86_64_GOTPCREL, -4);
1277 addRelocationForSymbol(RE, Value.SymbolName);
1279 // Bump our stub offset counter
1280 Section.StubOffset = StubOffset + getMaxStubSize();
1283 // Make the target call a call into the stub table.
1284 resolveRelocation(Section, Offset, StubAddress,
1285 ELF::R_X86_64_PC32, Addend);
1287 RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend,
1289 addRelocationForSection(RE, Value.SectionID);
1292 if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) {
1293 GOTEntries.push_back(Value);
1295 RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset);
1296 if (Value.SymbolName)
1297 addRelocationForSymbol(RE, Value.SymbolName);
1299 addRelocationForSection(RE, Value.SectionID);
1303 void RuntimeDyldELF::updateGOTEntries(StringRef Name, uint64_t Addr) {
1305 SmallVectorImpl<std::pair<SID, GOTRelocations> >::iterator it;
1306 SmallVectorImpl<std::pair<SID, GOTRelocations> >::iterator end = GOTs.end();
1308 for (it = GOTs.begin(); it != end; ++it) {
1309 GOTRelocations &GOTEntries = it->second;
1310 for (int i = 0, e = GOTEntries.size(); i != e; ++i) {
1311 if (GOTEntries[i].SymbolName != 0 && GOTEntries[i].SymbolName == Name) {
1312 GOTEntries[i].Offset = Addr;
1318 size_t RuntimeDyldELF::getGOTEntrySize() {
1319 // We don't use the GOT in all of these cases, but it's essentially free
1320 // to put them all here.
1323 case Triple::x86_64:
1324 case Triple::aarch64:
1326 case Triple::ppc64le:
1327 case Triple::systemz:
1328 Result = sizeof(uint64_t);
1334 case Triple::mipsel:
1335 Result = sizeof(uint32_t);
1337 default: llvm_unreachable("Unsupported CPU type!");
1342 uint64_t RuntimeDyldELF::findGOTEntry(uint64_t LoadAddress,
1345 const size_t GOTEntrySize = getGOTEntrySize();
1347 SmallVectorImpl<std::pair<SID, GOTRelocations> >::const_iterator it;
1348 SmallVectorImpl<std::pair<SID, GOTRelocations> >::const_iterator end = GOTs.end();
1351 for (it = GOTs.begin(); it != end; ++it) {
1352 SID GOTSectionID = it->first;
1353 const GOTRelocations &GOTEntries = it->second;
1355 // Find the matching entry in our vector.
1356 uint64_t SymbolOffset = 0;
1357 for (int i = 0, e = GOTEntries.size(); i != e; ++i) {
1358 if (GOTEntries[i].SymbolName == 0) {
1359 if (getSectionLoadAddress(GOTEntries[i].SectionID) == LoadAddress &&
1360 GOTEntries[i].Offset == Offset) {
1362 SymbolOffset = GOTEntries[i].Offset;
1366 // GOT entries for external symbols use the addend as the address when
1367 // the external symbol has been resolved.
1368 if (GOTEntries[i].Offset == LoadAddress) {
1370 // Don't use the Addend here. The relocation handler will use it.
1376 if (GOTIndex != -1) {
1377 if (GOTEntrySize == sizeof(uint64_t)) {
1378 uint64_t *LocalGOTAddr = (uint64_t*)getSectionAddress(GOTSectionID);
1379 // Fill in this entry with the address of the symbol being referenced.
1380 LocalGOTAddr[GOTIndex] = LoadAddress + SymbolOffset;
1382 uint32_t *LocalGOTAddr = (uint32_t*)getSectionAddress(GOTSectionID);
1383 // Fill in this entry with the address of the symbol being referenced.
1384 LocalGOTAddr[GOTIndex] = (uint32_t)(LoadAddress + SymbolOffset);
1387 // Calculate the load address of this entry
1388 return getSectionLoadAddress(GOTSectionID) + (GOTIndex * GOTEntrySize);
1392 assert(GOTIndex != -1 && "Unable to find requested GOT entry.");
1396 void RuntimeDyldELF::finalizeLoad(ObjSectionToIDMap &SectionMap) {
1397 // If necessary, allocate the global offset table
1399 // Allocate the GOT if necessary
1400 size_t numGOTEntries = GOTEntries.size();
1401 if (numGOTEntries != 0) {
1402 // Allocate memory for the section
1403 unsigned SectionID = Sections.size();
1404 size_t TotalSize = numGOTEntries * getGOTEntrySize();
1405 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, getGOTEntrySize(),
1406 SectionID, ".got", false);
1408 report_fatal_error("Unable to allocate memory for GOT!");
1410 GOTs.push_back(std::make_pair(SectionID, GOTEntries));
1411 Sections.push_back(SectionEntry(".got", Addr, TotalSize, 0));
1412 // For now, initialize all GOT entries to zero. We'll fill them in as
1413 // needed when GOT-based relocations are applied.
1414 memset(Addr, 0, TotalSize);
1418 report_fatal_error("Unable to allocate memory for GOT!");
1421 // Look for and record the EH frame section.
1422 ObjSectionToIDMap::iterator i, e;
1423 for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) {
1424 const SectionRef &Section = i->first;
1426 Section.getName(Name);
1427 if (Name == ".eh_frame") {
1428 UnregisteredEHFrameSections.push_back(i->second);
1434 bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const {
1435 if (Buffer->getBufferSize() < strlen(ELF::ElfMagic))
1437 return (memcmp(Buffer->getBufferStart(), ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0;
1440 bool RuntimeDyldELF::isCompatibleFile(const object::ObjectFile *Obj) const {
1441 return Obj->isELF();