1 //===-- RuntimeDyld.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 the MC-JIT runtime dynamic linker.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/ExecutionEngine/RuntimeDyld.h"
15 #include "JITRegistrar.h"
16 #include "ObjectImageCommon.h"
17 #include "RuntimeDyldCheckerImpl.h"
18 #include "RuntimeDyldELF.h"
19 #include "RuntimeDyldImpl.h"
20 #include "RuntimeDyldMachO.h"
21 #include "llvm/Object/ELF.h"
22 #include "llvm/Support/MathExtras.h"
23 #include "llvm/Support/MutexGuard.h"
26 using namespace llvm::object;
28 #define DEBUG_TYPE "dyld"
30 // Empty out-of-line virtual destructor as the key function.
31 RuntimeDyldImpl::~RuntimeDyldImpl() {}
33 // Pin the JITRegistrar's and ObjectImage*'s vtables to this file.
34 void JITRegistrar::anchor() {}
35 void ObjectImage::anchor() {}
36 void ObjectImageCommon::anchor() {}
40 void RuntimeDyldImpl::registerEHFrames() {}
42 void RuntimeDyldImpl::deregisterEHFrames() {}
45 static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
46 dbgs() << "----- Contents of section " << S.Name << " " << State << " -----";
48 if (S.Address == nullptr) {
49 dbgs() << "\n <section not emitted>\n";
53 const unsigned ColsPerRow = 16;
55 uint8_t *DataAddr = S.Address;
56 uint64_t LoadAddr = S.LoadAddress;
58 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
59 unsigned BytesRemaining = S.Size;
62 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr & ~(ColsPerRow - 1)) << ":";
63 while (StartPadding--)
67 while (BytesRemaining > 0) {
68 if ((LoadAddr & (ColsPerRow - 1)) == 0)
69 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
71 dbgs() << " " << format("%02x", *DataAddr);
82 // Resolve the relocations for all symbols we currently know about.
83 void RuntimeDyldImpl::resolveRelocations() {
84 MutexGuard locked(lock);
86 // First, resolve relocations associated with external symbols.
87 resolveExternalSymbols();
89 // Just iterate over the sections we have and resolve all the relocations
90 // in them. Gross overkill, but it gets the job done.
91 for (int i = 0, e = Sections.size(); i != e; ++i) {
92 // The Section here (Sections[i]) refers to the section in which the
93 // symbol for the relocation is located. The SectionID in the relocation
94 // entry provides the section to which the relocation will be applied.
95 uint64_t Addr = Sections[i].LoadAddress;
96 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"
97 << format("0x%x", Addr) << "\n");
98 DEBUG(dumpSectionMemory(Sections[i], "before relocations"));
99 resolveRelocationList(Relocations[i], Addr);
100 DEBUG(dumpSectionMemory(Sections[i], "after relocations"));
101 Relocations.erase(i);
105 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
106 uint64_t TargetAddress) {
107 MutexGuard locked(lock);
108 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
109 if (Sections[i].Address == LocalAddress) {
110 reassignSectionAddress(i, TargetAddress);
114 llvm_unreachable("Attempting to remap address of unknown section!");
117 static std::error_code getOffset(const SymbolRef &Sym, uint64_t &Result) {
119 if (std::error_code EC = Sym.getAddress(Address))
122 if (Address == UnknownAddressOrSize) {
123 Result = UnknownAddressOrSize;
124 return object_error::success;
127 const ObjectFile *Obj = Sym.getObject();
128 section_iterator SecI(Obj->section_begin());
129 if (std::error_code EC = Sym.getSection(SecI))
132 if (SecI == Obj->section_end()) {
133 Result = UnknownAddressOrSize;
134 return object_error::success;
137 uint64_t SectionAddress;
138 if (std::error_code EC = SecI->getAddress(SectionAddress))
141 Result = Address - SectionAddress;
142 return object_error::success;
145 std::unique_ptr<ObjectImage>
146 RuntimeDyldImpl::loadObject(std::unique_ptr<ObjectImage> Obj) {
147 MutexGuard locked(lock);
152 // Save information about our target
153 Arch = (Triple::ArchType)Obj->getArch();
154 IsTargetLittleEndian = Obj->getObjectFile()->isLittleEndian();
156 // Compute the memory size required to load all sections to be loaded
157 // and pass this information to the memory manager
158 if (MemMgr->needsToReserveAllocationSpace()) {
159 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
160 computeTotalAllocSize(*Obj, CodeSize, DataSizeRO, DataSizeRW);
161 MemMgr->reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
164 // Symbols found in this object
165 StringMap<SymbolLoc> LocalSymbols;
166 // Used sections from the object file
167 ObjSectionToIDMap LocalSections;
169 // Common symbols requiring allocation, with their sizes and alignments
170 CommonSymbolMap CommonSymbols;
171 // Maximum required total memory to allocate all common symbols
172 uint64_t CommonSize = 0;
175 DEBUG(dbgs() << "Parse symbols:\n");
176 for (symbol_iterator I = Obj->begin_symbols(), E = Obj->end_symbols(); I != E;
178 object::SymbolRef::Type SymType;
180 Check(I->getType(SymType));
181 Check(I->getName(Name));
183 uint32_t Flags = I->getFlags();
185 bool IsCommon = Flags & SymbolRef::SF_Common;
187 // Add the common symbols to a list. We'll allocate them all below.
188 if (!GlobalSymbolTable.count(Name)) {
190 Check(I->getAlignment(Align));
192 Check(I->getSize(Size));
193 CommonSize += Size + Align;
194 CommonSymbols[*I] = CommonSymbolInfo(Size, Align);
197 if (SymType == object::SymbolRef::ST_Function ||
198 SymType == object::SymbolRef::ST_Data ||
199 SymType == object::SymbolRef::ST_Unknown) {
201 StringRef SectionData;
203 section_iterator SI = Obj->end_sections();
204 Check(getOffset(*I, SectOffset));
205 Check(I->getSection(SI));
206 if (SI == Obj->end_sections())
208 Check(SI->getContents(SectionData));
209 Check(SI->isText(IsCode));
211 findOrEmitSection(*Obj, *SI, IsCode, LocalSections);
212 LocalSymbols[Name.data()] = SymbolLoc(SectionID, SectOffset);
213 DEBUG(dbgs() << "\tOffset: " << format("%p", (uintptr_t)SectOffset)
214 << " flags: " << Flags << " SID: " << SectionID);
215 GlobalSymbolTable[Name] = SymbolLoc(SectionID, SectOffset);
218 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name << "\n");
221 // Allocate common symbols
223 emitCommonSymbols(*Obj, CommonSymbols, CommonSize, GlobalSymbolTable);
225 // Parse and process relocations
226 DEBUG(dbgs() << "Parse relocations:\n");
227 for (section_iterator SI = Obj->begin_sections(), SE = Obj->end_sections();
229 unsigned SectionID = 0;
231 section_iterator RelocatedSection = SI->getRelocatedSection();
233 relocation_iterator I = SI->relocation_begin();
234 relocation_iterator E = SI->relocation_end();
236 if (I == E && !ProcessAllSections)
240 Check(RelocatedSection->isText(IsCode));
242 findOrEmitSection(*Obj, *RelocatedSection, IsCode, LocalSections);
243 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
246 I = processRelocationRef(SectionID, I, *Obj, LocalSections, LocalSymbols,
249 // If there is an attached checker, notify it about the stubs for this
250 // section so that they can be verified.
252 Checker->registerStubMap(Obj->getImageName(), SectionID, Stubs);
255 // Give the subclasses a chance to tie-up any loose ends.
256 finalizeLoad(*Obj, LocalSections);
261 // A helper method for computeTotalAllocSize.
262 // Computes the memory size required to allocate sections with the given sizes,
263 // assuming that all sections are allocated with the given alignment
265 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
266 uint64_t Alignment) {
267 uint64_t TotalSize = 0;
268 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
269 uint64_t AlignedSize =
270 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
271 TotalSize += AlignedSize;
276 // Compute an upper bound of the memory size that is required to load all
278 void RuntimeDyldImpl::computeTotalAllocSize(ObjectImage &Obj,
280 uint64_t &DataSizeRO,
281 uint64_t &DataSizeRW) {
282 // Compute the size of all sections required for execution
283 std::vector<uint64_t> CodeSectionSizes;
284 std::vector<uint64_t> ROSectionSizes;
285 std::vector<uint64_t> RWSectionSizes;
286 uint64_t MaxAlignment = sizeof(void *);
288 // Collect sizes of all sections to be loaded;
289 // also determine the max alignment of all sections
290 for (section_iterator SI = Obj.begin_sections(), SE = Obj.end_sections();
292 const SectionRef &Section = *SI;
295 Check(Section.isRequiredForExecution(IsRequired));
297 // Consider only the sections that are required to be loaded for execution
299 uint64_t DataSize = 0;
300 uint64_t Alignment64 = 0;
302 bool IsReadOnly = false;
304 Check(Section.getSize(DataSize));
305 Check(Section.getAlignment(Alignment64));
306 Check(Section.isText(IsCode));
307 Check(Section.isReadOnlyData(IsReadOnly));
308 Check(Section.getName(Name));
309 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
311 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
312 uint64_t SectionSize = DataSize + StubBufSize;
314 // The .eh_frame section (at least on Linux) needs an extra four bytes
316 // with zeroes added at the end. For MachO objects, this section has a
317 // slightly different name, so this won't have any effect for MachO
319 if (Name == ".eh_frame")
322 if (SectionSize > 0) {
323 // save the total size of the section
325 CodeSectionSizes.push_back(SectionSize);
326 } else if (IsReadOnly) {
327 ROSectionSizes.push_back(SectionSize);
329 RWSectionSizes.push_back(SectionSize);
331 // update the max alignment
332 if (Alignment > MaxAlignment) {
333 MaxAlignment = Alignment;
339 // Compute the size of all common symbols
340 uint64_t CommonSize = 0;
341 for (symbol_iterator I = Obj.begin_symbols(), E = Obj.end_symbols(); I != E;
343 uint32_t Flags = I->getFlags();
344 if (Flags & SymbolRef::SF_Common) {
345 // Add the common symbols to a list. We'll allocate them all below.
347 Check(I->getSize(Size));
351 if (CommonSize != 0) {
352 RWSectionSizes.push_back(CommonSize);
355 // Compute the required allocation space for each different type of sections
356 // (code, read-only data, read-write data) assuming that all sections are
357 // allocated with the max alignment. Note that we cannot compute with the
358 // individual alignments of the sections, because then the required size
359 // depends on the order, in which the sections are allocated.
360 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
361 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
362 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
365 // compute stub buffer size for the given section
366 unsigned RuntimeDyldImpl::computeSectionStubBufSize(ObjectImage &Obj,
367 const SectionRef &Section) {
368 unsigned StubSize = getMaxStubSize();
372 // FIXME: this is an inefficient way to handle this. We should computed the
373 // necessary section allocation size in loadObject by walking all the sections
375 unsigned StubBufSize = 0;
376 for (section_iterator SI = Obj.begin_sections(), SE = Obj.end_sections();
378 section_iterator RelSecI = SI->getRelocatedSection();
379 if (!(RelSecI == Section))
382 for (const RelocationRef &Reloc : SI->relocations()) {
384 StubBufSize += StubSize;
388 // Get section data size and alignment
389 uint64_t Alignment64;
391 Check(Section.getSize(DataSize));
392 Check(Section.getAlignment(Alignment64));
394 // Add stubbuf size alignment
395 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
396 unsigned StubAlignment = getStubAlignment();
397 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
398 if (StubAlignment > EndAlignment)
399 StubBufSize += StubAlignment - EndAlignment;
403 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
404 unsigned Size) const {
406 if (IsTargetLittleEndian) {
409 Result = (Result << 8) | *Src--;
412 Result = (Result << 8) | *Src++;
417 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
418 unsigned Size) const {
419 if (IsTargetLittleEndian) {
421 *Dst++ = Value & 0xFF;
427 *Dst-- = Value & 0xFF;
433 void RuntimeDyldImpl::emitCommonSymbols(ObjectImage &Obj,
434 const CommonSymbolMap &CommonSymbols,
436 SymbolTableMap &SymbolTable) {
437 // Allocate memory for the section
438 unsigned SectionID = Sections.size();
439 uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, sizeof(void *),
440 SectionID, StringRef(), false);
442 report_fatal_error("Unable to allocate memory for common symbols!");
444 Sections.push_back(SectionEntry("<common symbols>", Addr, TotalSize, 0));
445 memset(Addr, 0, TotalSize);
447 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
448 << format("%p", Addr) << " DataSize: " << TotalSize << "\n");
450 // Assign the address of each symbol
451 for (CommonSymbolMap::const_iterator it = CommonSymbols.begin(),
452 itEnd = CommonSymbols.end(); it != itEnd; ++it) {
453 uint64_t Size = it->second.first;
454 uint64_t Align = it->second.second;
456 it->first.getName(Name);
458 // This symbol has an alignment requirement.
459 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
461 Offset += AlignOffset;
462 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
463 << format("%p\n", Addr));
465 Obj.updateSymbolAddress(it->first, (uint64_t)Addr);
466 SymbolTable[Name.data()] = SymbolLoc(SectionID, Offset);
472 unsigned RuntimeDyldImpl::emitSection(ObjectImage &Obj,
473 const SectionRef &Section, bool IsCode) {
476 uint64_t Alignment64;
477 Check(Section.getContents(data));
478 Check(Section.getAlignment(Alignment64));
480 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
486 unsigned PaddingSize = 0;
487 unsigned StubBufSize = 0;
489 Check(Section.isRequiredForExecution(IsRequired));
490 Check(Section.isVirtual(IsVirtual));
491 Check(Section.isZeroInit(IsZeroInit));
492 Check(Section.isReadOnlyData(IsReadOnly));
493 Check(Section.getSize(DataSize));
494 Check(Section.getName(Name));
496 StubBufSize = computeSectionStubBufSize(Obj, Section);
498 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
499 // with zeroes added at the end. For MachO objects, this section has a
500 // slightly different name, so this won't have any effect for MachO objects.
501 if (Name == ".eh_frame")
505 unsigned SectionID = Sections.size();
507 const char *pData = nullptr;
509 // Some sections, such as debug info, don't need to be loaded for execution.
510 // Leave those where they are.
512 Allocate = DataSize + PaddingSize + StubBufSize;
513 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
515 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
518 report_fatal_error("Unable to allocate section memory!");
520 // Virtual sections have no data in the object image, so leave pData = 0
524 // Zero-initialize or copy the data from the image
525 if (IsZeroInit || IsVirtual)
526 memset(Addr, 0, DataSize);
528 memcpy(Addr, pData, DataSize);
530 // Fill in any extra bytes we allocated for padding
531 if (PaddingSize != 0) {
532 memset(Addr + DataSize, 0, PaddingSize);
533 // Update the DataSize variable so that the stub offset is set correctly.
534 DataSize += PaddingSize;
537 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
538 << " obj addr: " << format("%p", pData)
539 << " new addr: " << format("%p", Addr)
540 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
541 << " Allocate: " << Allocate << "\n");
542 Obj.updateSectionAddress(Section, (uint64_t)Addr);
544 // Even if we didn't load the section, we need to record an entry for it
545 // to handle later processing (and by 'handle' I mean don't do anything
546 // with these sections).
549 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
550 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
551 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
552 << " Allocate: " << Allocate << "\n");
555 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
558 Checker->registerSection(Obj.getImageName(), SectionID);
563 unsigned RuntimeDyldImpl::findOrEmitSection(ObjectImage &Obj,
564 const SectionRef &Section,
566 ObjSectionToIDMap &LocalSections) {
568 unsigned SectionID = 0;
569 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
570 if (i != LocalSections.end())
571 SectionID = i->second;
573 SectionID = emitSection(Obj, Section, IsCode);
574 LocalSections[Section] = SectionID;
579 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
580 unsigned SectionID) {
581 Relocations[SectionID].push_back(RE);
584 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
585 StringRef SymbolName) {
586 // Relocation by symbol. If the symbol is found in the global symbol table,
587 // create an appropriate section relocation. Otherwise, add it to
588 // ExternalSymbolRelocations.
589 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
590 if (Loc == GlobalSymbolTable.end()) {
591 ExternalSymbolRelocations[SymbolName].push_back(RE);
593 // Copy the RE since we want to modify its addend.
594 RelocationEntry RECopy = RE;
595 RECopy.Addend += Loc->second.second;
596 Relocations[Loc->second.first].push_back(RECopy);
600 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
601 unsigned AbiVariant) {
602 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
603 // This stub has to be able to access the full address space,
604 // since symbol lookup won't necessarily find a handy, in-range,
605 // PLT stub for functions which could be anywhere.
606 uint32_t *StubAddr = (uint32_t *)Addr;
608 // Stub can use ip0 (== x16) to calculate address
609 *StubAddr = 0xd2e00010; // movz ip0, #:abs_g3:<addr>
611 *StubAddr = 0xf2c00010; // movk ip0, #:abs_g2_nc:<addr>
613 *StubAddr = 0xf2a00010; // movk ip0, #:abs_g1_nc:<addr>
615 *StubAddr = 0xf2800010; // movk ip0, #:abs_g0_nc:<addr>
617 *StubAddr = 0xd61f0200; // br ip0
620 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
621 // TODO: There is only ARM far stub now. We should add the Thumb stub,
622 // and stubs for branches Thumb - ARM and ARM - Thumb.
623 uint32_t *StubAddr = (uint32_t *)Addr;
624 *StubAddr = 0xe51ff004; // ldr pc,<label>
625 return (uint8_t *)++StubAddr;
626 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
627 uint32_t *StubAddr = (uint32_t *)Addr;
628 // 0: 3c190000 lui t9,%hi(addr).
629 // 4: 27390000 addiu t9,t9,%lo(addr).
630 // 8: 03200008 jr t9.
632 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
633 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
635 *StubAddr = LuiT9Instr;
637 *StubAddr = AdduiT9Instr;
639 *StubAddr = JrT9Instr;
641 *StubAddr = NopInstr;
643 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
644 // Depending on which version of the ELF ABI is in use, we need to
645 // generate one of two variants of the stub. They both start with
646 // the same sequence to load the target address into r12.
647 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
648 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
649 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
650 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
651 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
652 if (AbiVariant == 2) {
653 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
654 // The address is already in r12 as required by the ABI. Branch to it.
655 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
656 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
657 writeInt32BE(Addr+28, 0x4E800420); // bctr
659 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
660 // Load the function address on r11 and sets it to control register. Also
661 // loads the function TOC in r2 and environment pointer to r11.
662 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
663 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
664 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
665 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
666 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
667 writeInt32BE(Addr+40, 0x4E800420); // bctr
670 } else if (Arch == Triple::systemz) {
671 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
672 writeInt16BE(Addr+2, 0x0000);
673 writeInt16BE(Addr+4, 0x0004);
674 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
675 // 8-byte address stored at Addr + 8
677 } else if (Arch == Triple::x86_64) {
679 *(Addr+1) = 0x25; // rip
680 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
681 } else if (Arch == Triple::x86) {
682 *Addr = 0xE9; // 32-bit pc-relative jump.
687 // Assign an address to a symbol name and resolve all the relocations
688 // associated with it.
689 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
691 // The address to use for relocation resolution is not
692 // the address of the local section buffer. We must be doing
693 // a remote execution environment of some sort. Relocations can't
694 // be applied until all the sections have been moved. The client must
695 // trigger this with a call to MCJIT::finalize() or
696 // RuntimeDyld::resolveRelocations().
698 // Addr is a uint64_t because we can't assume the pointer width
699 // of the target is the same as that of the host. Just use a generic
700 // "big enough" type.
701 DEBUG(dbgs() << "Reassigning address for section "
702 << SectionID << " (" << Sections[SectionID].Name << "): "
703 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
704 << format("0x%016" PRIx64, Addr) << "\n");
705 Sections[SectionID].LoadAddress = Addr;
708 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
710 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
711 const RelocationEntry &RE = Relocs[i];
712 // Ignore relocations for sections that were not loaded
713 if (Sections[RE.SectionID].Address == nullptr)
715 resolveRelocation(RE, Value);
719 void RuntimeDyldImpl::resolveExternalSymbols() {
720 while (!ExternalSymbolRelocations.empty()) {
721 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
723 StringRef Name = i->first();
724 if (Name.size() == 0) {
725 // This is an absolute symbol, use an address of zero.
726 DEBUG(dbgs() << "Resolving absolute relocations."
728 RelocationList &Relocs = i->second;
729 resolveRelocationList(Relocs, 0);
732 SymbolTableMap::const_iterator Loc = GlobalSymbolTable.find(Name);
733 if (Loc == GlobalSymbolTable.end()) {
734 // This is an external symbol, try to get its address from
736 Addr = MemMgr->getSymbolAddress(Name.data());
737 // The call to getSymbolAddress may have caused additional modules to
738 // be loaded, which may have added new entries to the
739 // ExternalSymbolRelocations map. Consquently, we need to update our
740 // iterator. This is also why retrieval of the relocation list
741 // associated with this symbol is deferred until below this point.
742 // New entries may have been added to the relocation list.
743 i = ExternalSymbolRelocations.find(Name);
745 // We found the symbol in our global table. It was probably in a
746 // Module that we loaded previously.
747 SymbolLoc SymLoc = Loc->second;
748 Addr = getSectionLoadAddress(SymLoc.first) + SymLoc.second;
751 // FIXME: Implement error handling that doesn't kill the host program!
753 report_fatal_error("Program used external function '" + Name +
754 "' which could not be resolved!");
756 updateGOTEntries(Name, Addr);
757 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
758 << format("0x%lx", Addr) << "\n");
759 // This list may have been updated when we called getSymbolAddress, so
760 // don't change this code to get the list earlier.
761 RelocationList &Relocs = i->second;
762 resolveRelocationList(Relocs, Addr);
765 ExternalSymbolRelocations.erase(i);
769 //===----------------------------------------------------------------------===//
770 // RuntimeDyld class implementation
771 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
772 // FIXME: There's a potential issue lurking here if a single instance of
773 // RuntimeDyld is used to load multiple objects. The current implementation
774 // associates a single memory manager with a RuntimeDyld instance. Even
775 // though the public class spawns a new 'impl' instance for each load,
776 // they share a single memory manager. This can become a problem when page
777 // permissions are applied.
780 ProcessAllSections = false;
784 RuntimeDyld::~RuntimeDyld() {}
786 static std::unique_ptr<RuntimeDyldELF>
787 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
788 RuntimeDyldCheckerImpl *Checker) {
789 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
790 Dyld->setProcessAllSections(ProcessAllSections);
791 Dyld->setRuntimeDyldChecker(Checker);
795 static std::unique_ptr<RuntimeDyldMachO>
796 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
797 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
798 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
799 Dyld->setProcessAllSections(ProcessAllSections);
800 Dyld->setRuntimeDyldChecker(Checker);
804 std::unique_ptr<ObjectImage>
805 RuntimeDyld::loadObject(std::unique_ptr<ObjectFile> InputObject) {
806 std::unique_ptr<ObjectImage> InputImage;
808 ObjectFile &Obj = *InputObject;
810 if (InputObject->isELF()) {
811 InputImage.reset(RuntimeDyldELF::createObjectImageFromFile(std::move(InputObject)));
813 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
814 } else if (InputObject->isMachO()) {
815 InputImage.reset(RuntimeDyldMachO::createObjectImageFromFile(std::move(InputObject)));
817 Dyld = createRuntimeDyldMachO(
818 static_cast<Triple::ArchType>(InputImage->getArch()), MM,
819 ProcessAllSections, Checker);
821 report_fatal_error("Incompatible object format!");
823 if (!Dyld->isCompatibleFile(&Obj))
824 report_fatal_error("Incompatible object format!");
826 return Dyld->loadObject(std::move(InputImage));
829 std::unique_ptr<ObjectImage>
830 RuntimeDyld::loadObject(std::unique_ptr<ObjectBuffer> InputBuffer) {
831 std::unique_ptr<ObjectImage> InputImage;
832 sys::fs::file_magic Type = sys::fs::identify_magic(InputBuffer->getBuffer());
833 auto *InputBufferPtr = InputBuffer.get();
836 case sys::fs::file_magic::elf_relocatable:
837 case sys::fs::file_magic::elf_executable:
838 case sys::fs::file_magic::elf_shared_object:
839 case sys::fs::file_magic::elf_core:
840 InputImage = RuntimeDyldELF::createObjectImage(std::move(InputBuffer));
842 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
844 case sys::fs::file_magic::macho_object:
845 case sys::fs::file_magic::macho_executable:
846 case sys::fs::file_magic::macho_fixed_virtual_memory_shared_lib:
847 case sys::fs::file_magic::macho_core:
848 case sys::fs::file_magic::macho_preload_executable:
849 case sys::fs::file_magic::macho_dynamically_linked_shared_lib:
850 case sys::fs::file_magic::macho_dynamic_linker:
851 case sys::fs::file_magic::macho_bundle:
852 case sys::fs::file_magic::macho_dynamically_linked_shared_lib_stub:
853 case sys::fs::file_magic::macho_dsym_companion:
854 InputImage = RuntimeDyldMachO::createObjectImage(std::move(InputBuffer));
856 Dyld = createRuntimeDyldMachO(
857 static_cast<Triple::ArchType>(InputImage->getArch()), MM,
858 ProcessAllSections, Checker);
860 case sys::fs::file_magic::unknown:
861 case sys::fs::file_magic::bitcode:
862 case sys::fs::file_magic::archive:
863 case sys::fs::file_magic::coff_object:
864 case sys::fs::file_magic::coff_import_library:
865 case sys::fs::file_magic::pecoff_executable:
866 case sys::fs::file_magic::macho_universal_binary:
867 case sys::fs::file_magic::windows_resource:
868 report_fatal_error("Incompatible object format!");
871 if (!Dyld->isCompatibleFormat(InputBufferPtr))
872 report_fatal_error("Incompatible object format!");
874 return Dyld->loadObject(std::move(InputImage));
877 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
880 return Dyld->getSymbolAddress(Name);
883 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
886 return Dyld->getSymbolLoadAddress(Name);
889 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
891 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
892 Dyld->reassignSectionAddress(SectionID, Addr);
895 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
896 uint64_t TargetAddress) {
897 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
900 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
902 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
904 void RuntimeDyld::registerEHFrames() {
906 Dyld->registerEHFrames();
909 void RuntimeDyld::deregisterEHFrames() {
911 Dyld->deregisterEHFrames();
914 } // end namespace llvm