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 "RuntimeDyldCheckerImpl.h"
16 #include "RuntimeDyldELF.h"
17 #include "RuntimeDyldImpl.h"
18 #include "RuntimeDyldMachO.h"
19 #include "llvm/Object/ELFObjectFile.h"
20 #include "llvm/Support/MathExtras.h"
21 #include "llvm/Support/MutexGuard.h"
24 using namespace llvm::object;
26 #define DEBUG_TYPE "dyld"
28 // Empty out-of-line virtual destructor as the key function.
29 RuntimeDyldImpl::~RuntimeDyldImpl() {}
31 // Pin LoadedObjectInfo's vtables to this file.
32 void RuntimeDyld::LoadedObjectInfo::anchor() {}
36 void RuntimeDyldImpl::registerEHFrames() {}
38 void RuntimeDyldImpl::deregisterEHFrames() {}
41 static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
42 dbgs() << "----- Contents of section " << S.Name << " " << State << " -----";
44 if (S.Address == nullptr) {
45 dbgs() << "\n <section not emitted>\n";
49 const unsigned ColsPerRow = 16;
51 uint8_t *DataAddr = S.Address;
52 uint64_t LoadAddr = S.LoadAddress;
54 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
55 unsigned BytesRemaining = S.Size;
58 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr & ~(ColsPerRow - 1)) << ":";
59 while (StartPadding--)
63 while (BytesRemaining > 0) {
64 if ((LoadAddr & (ColsPerRow - 1)) == 0)
65 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
67 dbgs() << " " << format("%02x", *DataAddr);
78 // Resolve the relocations for all symbols we currently know about.
79 void RuntimeDyldImpl::resolveRelocations() {
80 MutexGuard locked(lock);
82 // First, resolve relocations associated with external symbols.
83 resolveExternalSymbols();
85 // Just iterate over the sections we have and resolve all the relocations
86 // in them. Gross overkill, but it gets the job done.
87 for (int i = 0, e = Sections.size(); i != e; ++i) {
88 // The Section here (Sections[i]) refers to the section in which the
89 // symbol for the relocation is located. The SectionID in the relocation
90 // entry provides the section to which the relocation will be applied.
91 uint64_t Addr = Sections[i].LoadAddress;
92 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"
93 << format("0x%x", Addr) << "\n");
94 DEBUG(dumpSectionMemory(Sections[i], "before relocations"));
95 resolveRelocationList(Relocations[i], Addr);
96 DEBUG(dumpSectionMemory(Sections[i], "after relocations"));
101 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
102 uint64_t TargetAddress) {
103 MutexGuard locked(lock);
104 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
105 if (Sections[i].Address == LocalAddress) {
106 reassignSectionAddress(i, TargetAddress);
110 llvm_unreachable("Attempting to remap address of unknown section!");
113 static std::error_code getOffset(const SymbolRef &Sym, uint64_t &Result) {
115 if (std::error_code EC = Sym.getAddress(Address))
118 if (Address == UnknownAddressOrSize) {
119 Result = UnknownAddressOrSize;
120 return object_error::success;
123 const ObjectFile *Obj = Sym.getObject();
124 section_iterator SecI(Obj->section_begin());
125 if (std::error_code EC = Sym.getSection(SecI))
128 if (SecI == Obj->section_end()) {
129 Result = UnknownAddressOrSize;
130 return object_error::success;
133 uint64_t SectionAddress = SecI->getAddress();
134 Result = Address - SectionAddress;
135 return object_error::success;
138 std::pair<unsigned, unsigned>
139 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
140 MutexGuard locked(lock);
142 // Grab the first Section ID. We'll use this later to construct the underlying
143 // range for the returned LoadedObjectInfo.
144 unsigned SectionsAddedBeginIdx = Sections.size();
146 // Save information about our target
147 Arch = (Triple::ArchType)Obj.getArch();
148 IsTargetLittleEndian = Obj.isLittleEndian();
150 // Compute the memory size required to load all sections to be loaded
151 // and pass this information to the memory manager
152 if (MemMgr->needsToReserveAllocationSpace()) {
153 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
154 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
155 MemMgr->reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
158 // Used sections from the object file
159 ObjSectionToIDMap LocalSections;
161 // Common symbols requiring allocation, with their sizes and alignments
162 CommonSymbolList CommonSymbols;
165 DEBUG(dbgs() << "Parse symbols:\n");
166 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
168 uint32_t Flags = I->getFlags();
170 bool IsCommon = Flags & SymbolRef::SF_Common;
172 CommonSymbols.push_back(*I);
174 object::SymbolRef::Type SymType;
175 Check(I->getType(SymType));
177 if (SymType == object::SymbolRef::ST_Function ||
178 SymType == object::SymbolRef::ST_Data ||
179 SymType == object::SymbolRef::ST_Unknown) {
183 Check(I->getName(Name));
184 Check(getOffset(*I, SectOffset));
185 section_iterator SI = Obj.section_end();
186 Check(I->getSection(SI));
187 if (SI == Obj.section_end())
189 StringRef SectionData;
190 Check(SI->getContents(SectionData));
191 bool IsCode = SI->isText();
193 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
194 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
195 << " SID: " << SectionID << " Offset: "
196 << format("%p", (uintptr_t)SectOffset)
197 << " flags: " << Flags << "\n");
198 SymbolInfo::Visibility Vis =
199 (Flags & SymbolRef::SF_Exported) ?
200 SymbolInfo::Default : SymbolInfo::Hidden;
201 GlobalSymbolTable[Name] = SymbolInfo(SectionID, SectOffset, Vis);
206 // Allocate common symbols
207 emitCommonSymbols(Obj, CommonSymbols);
209 // Parse and process relocations
210 DEBUG(dbgs() << "Parse relocations:\n");
211 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
213 unsigned SectionID = 0;
215 section_iterator RelocatedSection = SI->getRelocatedSection();
217 relocation_iterator I = SI->relocation_begin();
218 relocation_iterator E = SI->relocation_end();
220 if (I == E && !ProcessAllSections)
223 bool IsCode = RelocatedSection->isText();
225 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
226 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
229 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
231 // If there is an attached checker, notify it about the stubs for this
232 // section so that they can be verified.
234 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
237 // Give the subclasses a chance to tie-up any loose ends.
238 finalizeLoad(Obj, LocalSections);
240 unsigned SectionsAddedEndIdx = Sections.size();
242 return std::make_pair(SectionsAddedBeginIdx, SectionsAddedEndIdx);
245 // A helper method for computeTotalAllocSize.
246 // Computes the memory size required to allocate sections with the given sizes,
247 // assuming that all sections are allocated with the given alignment
249 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
250 uint64_t Alignment) {
251 uint64_t TotalSize = 0;
252 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
253 uint64_t AlignedSize =
254 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
255 TotalSize += AlignedSize;
260 static bool isRequiredForExecution(const SectionRef &Section) {
261 const ObjectFile *Obj = Section.getObject();
262 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
263 return ELFObj->getSectionFlags(Section) & ELF::SHF_ALLOC;
264 assert(isa<MachOObjectFile>(Obj));
268 static bool isReadOnlyData(const SectionRef &Section) {
269 const ObjectFile *Obj = Section.getObject();
270 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
271 return !(ELFObj->getSectionFlags(Section) &
272 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
273 assert(isa<MachOObjectFile>(Obj));
277 static bool isZeroInit(const SectionRef &Section) {
278 const ObjectFile *Obj = Section.getObject();
279 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
280 return ELFObj->getSectionType(Section) == ELF::SHT_NOBITS;
282 auto *MachO = cast<MachOObjectFile>(Obj);
283 unsigned SectionType = MachO->getSectionType(Section);
284 return SectionType == MachO::S_ZEROFILL ||
285 SectionType == MachO::S_GB_ZEROFILL;
288 // Compute an upper bound of the memory size that is required to load all
290 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
292 uint64_t &DataSizeRO,
293 uint64_t &DataSizeRW) {
294 // Compute the size of all sections required for execution
295 std::vector<uint64_t> CodeSectionSizes;
296 std::vector<uint64_t> ROSectionSizes;
297 std::vector<uint64_t> RWSectionSizes;
298 uint64_t MaxAlignment = sizeof(void *);
300 // Collect sizes of all sections to be loaded;
301 // also determine the max alignment of all sections
302 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
304 const SectionRef &Section = *SI;
306 bool IsRequired = isRequiredForExecution(Section);
308 // Consider only the sections that are required to be loaded for execution
311 uint64_t DataSize = Section.getSize();
312 uint64_t Alignment64 = Section.getAlignment();
313 bool IsCode = Section.isText();
314 bool IsReadOnly = isReadOnlyData(Section);
315 Check(Section.getName(Name));
316 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
318 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
319 uint64_t SectionSize = DataSize + StubBufSize;
321 // The .eh_frame section (at least on Linux) needs an extra four bytes
323 // with zeroes added at the end. For MachO objects, this section has a
324 // slightly different name, so this won't have any effect for MachO
326 if (Name == ".eh_frame")
329 if (SectionSize > 0) {
330 // save the total size of the section
332 CodeSectionSizes.push_back(SectionSize);
333 } else if (IsReadOnly) {
334 ROSectionSizes.push_back(SectionSize);
336 RWSectionSizes.push_back(SectionSize);
338 // update the max alignment
339 if (Alignment > MaxAlignment) {
340 MaxAlignment = Alignment;
346 // Compute the size of all common symbols
347 uint64_t CommonSize = 0;
348 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
350 uint32_t Flags = I->getFlags();
351 if (Flags & SymbolRef::SF_Common) {
352 // Add the common symbols to a list. We'll allocate them all below.
354 Check(I->getSize(Size));
358 if (CommonSize != 0) {
359 RWSectionSizes.push_back(CommonSize);
362 // Compute the required allocation space for each different type of sections
363 // (code, read-only data, read-write data) assuming that all sections are
364 // allocated with the max alignment. Note that we cannot compute with the
365 // individual alignments of the sections, because then the required size
366 // depends on the order, in which the sections are allocated.
367 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
368 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
369 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
372 // compute stub buffer size for the given section
373 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
374 const SectionRef &Section) {
375 unsigned StubSize = getMaxStubSize();
379 // FIXME: this is an inefficient way to handle this. We should computed the
380 // necessary section allocation size in loadObject by walking all the sections
382 unsigned StubBufSize = 0;
383 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
385 section_iterator RelSecI = SI->getRelocatedSection();
386 if (!(RelSecI == Section))
389 for (const RelocationRef &Reloc : SI->relocations()) {
391 StubBufSize += StubSize;
395 // Get section data size and alignment
396 uint64_t DataSize = Section.getSize();
397 uint64_t Alignment64 = Section.getAlignment();
399 // Add stubbuf size alignment
400 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
401 unsigned StubAlignment = getStubAlignment();
402 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
403 if (StubAlignment > EndAlignment)
404 StubBufSize += StubAlignment - EndAlignment;
408 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
409 unsigned Size) const {
411 if (IsTargetLittleEndian) {
414 Result = (Result << 8) | *Src--;
417 Result = (Result << 8) | *Src++;
422 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
423 unsigned Size) const {
424 if (IsTargetLittleEndian) {
426 *Dst++ = Value & 0xFF;
432 *Dst-- = Value & 0xFF;
438 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
439 CommonSymbolList &CommonSymbols) {
440 if (CommonSymbols.empty())
443 uint64_t CommonSize = 0;
444 CommonSymbolList SymbolsToAllocate;
446 DEBUG(dbgs() << "Processing common symbols...\n");
448 for (const auto &Sym : CommonSymbols) {
450 Check(Sym.getName(Name));
452 // Skip common symbols already elsewhere.
453 if (GlobalSymbolTable.count(Name) ||
454 MemMgr->getSymbolAddressInLogicalDylib(Name)) {
455 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
462 Check(Sym.getAlignment(Align));
463 Check(Sym.getSize(Size));
465 CommonSize += Align + Size;
466 SymbolsToAllocate.push_back(Sym);
469 // Allocate memory for the section
470 unsigned SectionID = Sections.size();
471 uint8_t *Addr = MemMgr->allocateDataSection(CommonSize, sizeof(void *),
472 SectionID, StringRef(), false);
474 report_fatal_error("Unable to allocate memory for common symbols!");
476 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
477 memset(Addr, 0, CommonSize);
479 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
480 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
482 // Assign the address of each symbol
483 for (auto &Sym : SymbolsToAllocate) {
487 Check(Sym.getAlignment(Align));
488 Check(Sym.getSize(Size));
489 Check(Sym.getName(Name));
491 // This symbol has an alignment requirement.
492 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
494 Offset += AlignOffset;
496 uint32_t Flags = Sym.getFlags();
497 SymbolInfo::Visibility Vis =
498 (Flags & SymbolRef::SF_Exported) ?
499 SymbolInfo::Default : SymbolInfo::Hidden;
500 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
501 << format("%p", Addr) << "\n");
502 GlobalSymbolTable[Name] = SymbolInfo(SectionID, Offset, Vis);
508 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
509 const SectionRef &Section, bool IsCode) {
512 Check(Section.getContents(data));
513 uint64_t Alignment64 = Section.getAlignment();
515 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
516 unsigned PaddingSize = 0;
517 unsigned StubBufSize = 0;
519 bool IsRequired = isRequiredForExecution(Section);
520 bool IsVirtual = Section.isVirtual();
521 bool IsZeroInit = isZeroInit(Section);
522 bool IsReadOnly = isReadOnlyData(Section);
523 uint64_t DataSize = Section.getSize();
524 Check(Section.getName(Name));
526 StubBufSize = computeSectionStubBufSize(Obj, Section);
528 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
529 // with zeroes added at the end. For MachO objects, this section has a
530 // slightly different name, so this won't have any effect for MachO objects.
531 if (Name == ".eh_frame")
535 unsigned SectionID = Sections.size();
537 const char *pData = nullptr;
539 // Some sections, such as debug info, don't need to be loaded for execution.
540 // Leave those where they are.
542 Allocate = DataSize + PaddingSize + StubBufSize;
543 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
545 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
548 report_fatal_error("Unable to allocate section memory!");
550 // Virtual sections have no data in the object image, so leave pData = 0
554 // Zero-initialize or copy the data from the image
555 if (IsZeroInit || IsVirtual)
556 memset(Addr, 0, DataSize);
558 memcpy(Addr, pData, DataSize);
560 // Fill in any extra bytes we allocated for padding
561 if (PaddingSize != 0) {
562 memset(Addr + DataSize, 0, PaddingSize);
563 // Update the DataSize variable so that the stub offset is set correctly.
564 DataSize += PaddingSize;
567 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
568 << " obj addr: " << format("%p", pData)
569 << " new addr: " << format("%p", Addr)
570 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
571 << " Allocate: " << Allocate << "\n");
573 // Even if we didn't load the section, we need to record an entry for it
574 // to handle later processing (and by 'handle' I mean don't do anything
575 // with these sections).
578 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
579 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
580 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
581 << " Allocate: " << Allocate << "\n");
584 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
587 Checker->registerSection(Obj.getFileName(), SectionID);
592 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
593 const SectionRef &Section,
595 ObjSectionToIDMap &LocalSections) {
597 unsigned SectionID = 0;
598 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
599 if (i != LocalSections.end())
600 SectionID = i->second;
602 SectionID = emitSection(Obj, Section, IsCode);
603 LocalSections[Section] = SectionID;
608 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
609 unsigned SectionID) {
610 Relocations[SectionID].push_back(RE);
613 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
614 StringRef SymbolName) {
615 // Relocation by symbol. If the symbol is found in the global symbol table,
616 // create an appropriate section relocation. Otherwise, add it to
617 // ExternalSymbolRelocations.
618 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
619 if (Loc == GlobalSymbolTable.end()) {
620 ExternalSymbolRelocations[SymbolName].push_back(RE);
622 // Copy the RE since we want to modify its addend.
623 RelocationEntry RECopy = RE;
624 const auto &SymInfo = Loc->second;
625 RECopy.Addend += SymInfo.getOffset();
626 Relocations[SymInfo.getSectionID()].push_back(RECopy);
630 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
631 unsigned AbiVariant) {
632 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
633 // This stub has to be able to access the full address space,
634 // since symbol lookup won't necessarily find a handy, in-range,
635 // PLT stub for functions which could be anywhere.
636 // Stub can use ip0 (== x16) to calculate address
637 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
638 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
639 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
640 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
641 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
644 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
645 // TODO: There is only ARM far stub now. We should add the Thumb stub,
646 // and stubs for branches Thumb - ARM and ARM - Thumb.
647 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
649 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
650 // 0: 3c190000 lui t9,%hi(addr).
651 // 4: 27390000 addiu t9,t9,%lo(addr).
652 // 8: 03200008 jr t9.
654 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
655 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
657 writeBytesUnaligned(LuiT9Instr, Addr, 4);
658 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
659 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
660 writeBytesUnaligned(NopInstr, Addr+12, 4);
662 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
663 // Depending on which version of the ELF ABI is in use, we need to
664 // generate one of two variants of the stub. They both start with
665 // the same sequence to load the target address into r12.
666 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
667 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
668 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
669 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
670 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
671 if (AbiVariant == 2) {
672 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
673 // The address is already in r12 as required by the ABI. Branch to it.
674 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
675 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
676 writeInt32BE(Addr+28, 0x4E800420); // bctr
678 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
679 // Load the function address on r11 and sets it to control register. Also
680 // loads the function TOC in r2 and environment pointer to r11.
681 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
682 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
683 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
684 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
685 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
686 writeInt32BE(Addr+40, 0x4E800420); // bctr
689 } else if (Arch == Triple::systemz) {
690 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
691 writeInt16BE(Addr+2, 0x0000);
692 writeInt16BE(Addr+4, 0x0004);
693 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
694 // 8-byte address stored at Addr + 8
696 } else if (Arch == Triple::x86_64) {
698 *(Addr+1) = 0x25; // rip
699 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
700 } else if (Arch == Triple::x86) {
701 *Addr = 0xE9; // 32-bit pc-relative jump.
706 // Assign an address to a symbol name and resolve all the relocations
707 // associated with it.
708 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
710 // The address to use for relocation resolution is not
711 // the address of the local section buffer. We must be doing
712 // a remote execution environment of some sort. Relocations can't
713 // be applied until all the sections have been moved. The client must
714 // trigger this with a call to MCJIT::finalize() or
715 // RuntimeDyld::resolveRelocations().
717 // Addr is a uint64_t because we can't assume the pointer width
718 // of the target is the same as that of the host. Just use a generic
719 // "big enough" type.
720 DEBUG(dbgs() << "Reassigning address for section "
721 << SectionID << " (" << Sections[SectionID].Name << "): "
722 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
723 << format("0x%016" PRIx64, Addr) << "\n");
724 Sections[SectionID].LoadAddress = Addr;
727 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
729 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
730 const RelocationEntry &RE = Relocs[i];
731 // Ignore relocations for sections that were not loaded
732 if (Sections[RE.SectionID].Address == nullptr)
734 resolveRelocation(RE, Value);
738 void RuntimeDyldImpl::resolveExternalSymbols() {
739 while (!ExternalSymbolRelocations.empty()) {
740 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
742 StringRef Name = i->first();
743 if (Name.size() == 0) {
744 // This is an absolute symbol, use an address of zero.
745 DEBUG(dbgs() << "Resolving absolute relocations."
747 RelocationList &Relocs = i->second;
748 resolveRelocationList(Relocs, 0);
751 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
752 if (Loc == GlobalSymbolTable.end()) {
753 // This is an external symbol, try to get its address from
755 Addr = MemMgr->getSymbolAddress(Name.data());
756 // The call to getSymbolAddress may have caused additional modules to
757 // be loaded, which may have added new entries to the
758 // ExternalSymbolRelocations map. Consquently, we need to update our
759 // iterator. This is also why retrieval of the relocation list
760 // associated with this symbol is deferred until below this point.
761 // New entries may have been added to the relocation list.
762 i = ExternalSymbolRelocations.find(Name);
764 // We found the symbol in our global table. It was probably in a
765 // Module that we loaded previously.
766 const auto &SymInfo = Loc->second;
767 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
771 // FIXME: Implement error handling that doesn't kill the host program!
773 report_fatal_error("Program used external function '" + Name +
774 "' which could not be resolved!");
776 updateGOTEntries(Name, Addr);
777 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
778 << format("0x%lx", Addr) << "\n");
779 // This list may have been updated when we called getSymbolAddress, so
780 // don't change this code to get the list earlier.
781 RelocationList &Relocs = i->second;
782 resolveRelocationList(Relocs, Addr);
785 ExternalSymbolRelocations.erase(i);
789 //===----------------------------------------------------------------------===//
790 // RuntimeDyld class implementation
792 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
793 StringRef SectionName) const {
794 for (unsigned I = BeginIdx; I != EndIdx; ++I)
795 if (RTDyld.Sections[I].Name == SectionName)
796 return RTDyld.Sections[I].LoadAddress;
801 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
802 // FIXME: There's a potential issue lurking here if a single instance of
803 // RuntimeDyld is used to load multiple objects. The current implementation
804 // associates a single memory manager with a RuntimeDyld instance. Even
805 // though the public class spawns a new 'impl' instance for each load,
806 // they share a single memory manager. This can become a problem when page
807 // permissions are applied.
810 ProcessAllSections = false;
814 RuntimeDyld::~RuntimeDyld() {}
816 static std::unique_ptr<RuntimeDyldELF>
817 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
818 RuntimeDyldCheckerImpl *Checker) {
819 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
820 Dyld->setProcessAllSections(ProcessAllSections);
821 Dyld->setRuntimeDyldChecker(Checker);
825 static std::unique_ptr<RuntimeDyldMachO>
826 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
827 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
828 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
829 Dyld->setProcessAllSections(ProcessAllSections);
830 Dyld->setRuntimeDyldChecker(Checker);
834 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
835 RuntimeDyld::loadObject(const ObjectFile &Obj) {
838 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
839 else if (Obj.isMachO())
840 Dyld = createRuntimeDyldMachO(
841 static_cast<Triple::ArchType>(Obj.getArch()), MM,
842 ProcessAllSections, Checker);
844 report_fatal_error("Incompatible object format!");
847 if (!Dyld->isCompatibleFile(Obj))
848 report_fatal_error("Incompatible object format!");
850 return Dyld->loadObject(Obj);
853 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
856 return Dyld->getSymbolAddress(Name);
859 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
862 return Dyld->getSymbolLoadAddress(Name);
865 uint64_t RuntimeDyld::getExportedSymbolLoadAddress(StringRef Name) const {
868 return Dyld->getExportedSymbolLoadAddress(Name);
871 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
873 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
874 Dyld->reassignSectionAddress(SectionID, Addr);
877 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
878 uint64_t TargetAddress) {
879 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
882 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
884 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
886 void RuntimeDyld::registerEHFrames() {
888 Dyld->registerEHFrames();
891 void RuntimeDyld::deregisterEHFrames() {
893 Dyld->deregisterEHFrames();
896 } // end namespace llvm