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 if (RelocatedSection == SE)
220 relocation_iterator I = SI->relocation_begin();
221 relocation_iterator E = SI->relocation_end();
223 if (I == E && !ProcessAllSections)
226 bool IsCode = RelocatedSection->isText();
228 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
229 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
232 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
234 // If there is an attached checker, notify it about the stubs for this
235 // section so that they can be verified.
237 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
240 // Give the subclasses a chance to tie-up any loose ends.
241 finalizeLoad(Obj, LocalSections);
243 unsigned SectionsAddedEndIdx = Sections.size();
245 return std::make_pair(SectionsAddedBeginIdx, SectionsAddedEndIdx);
248 // A helper method for computeTotalAllocSize.
249 // Computes the memory size required to allocate sections with the given sizes,
250 // assuming that all sections are allocated with the given alignment
252 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
253 uint64_t Alignment) {
254 uint64_t TotalSize = 0;
255 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
256 uint64_t AlignedSize =
257 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
258 TotalSize += AlignedSize;
263 static bool isRequiredForExecution(const SectionRef &Section) {
264 const ObjectFile *Obj = Section.getObject();
265 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
266 return ELFObj->getSectionFlags(Section) & ELF::SHF_ALLOC;
267 assert(isa<MachOObjectFile>(Obj));
271 static bool isReadOnlyData(const SectionRef &Section) {
272 const ObjectFile *Obj = Section.getObject();
273 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
274 return !(ELFObj->getSectionFlags(Section) &
275 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
276 assert(isa<MachOObjectFile>(Obj));
280 static bool isZeroInit(const SectionRef &Section) {
281 const ObjectFile *Obj = Section.getObject();
282 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
283 return ELFObj->getSectionType(Section) == ELF::SHT_NOBITS;
285 auto *MachO = cast<MachOObjectFile>(Obj);
286 unsigned SectionType = MachO->getSectionType(Section);
287 return SectionType == MachO::S_ZEROFILL ||
288 SectionType == MachO::S_GB_ZEROFILL;
291 // Compute an upper bound of the memory size that is required to load all
293 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
295 uint64_t &DataSizeRO,
296 uint64_t &DataSizeRW) {
297 // Compute the size of all sections required for execution
298 std::vector<uint64_t> CodeSectionSizes;
299 std::vector<uint64_t> ROSectionSizes;
300 std::vector<uint64_t> RWSectionSizes;
301 uint64_t MaxAlignment = sizeof(void *);
303 // Collect sizes of all sections to be loaded;
304 // also determine the max alignment of all sections
305 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
307 const SectionRef &Section = *SI;
309 bool IsRequired = isRequiredForExecution(Section);
311 // Consider only the sections that are required to be loaded for execution
314 uint64_t DataSize = Section.getSize();
315 uint64_t Alignment64 = Section.getAlignment();
316 bool IsCode = Section.isText();
317 bool IsReadOnly = isReadOnlyData(Section);
318 Check(Section.getName(Name));
319 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
321 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
322 uint64_t SectionSize = DataSize + StubBufSize;
324 // The .eh_frame section (at least on Linux) needs an extra four bytes
326 // with zeroes added at the end. For MachO objects, this section has a
327 // slightly different name, so this won't have any effect for MachO
329 if (Name == ".eh_frame")
332 if (SectionSize > 0) {
333 // save the total size of the section
335 CodeSectionSizes.push_back(SectionSize);
336 } else if (IsReadOnly) {
337 ROSectionSizes.push_back(SectionSize);
339 RWSectionSizes.push_back(SectionSize);
341 // update the max alignment
342 if (Alignment > MaxAlignment) {
343 MaxAlignment = Alignment;
349 // Compute the size of all common symbols
350 uint64_t CommonSize = 0;
351 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
353 uint32_t Flags = I->getFlags();
354 if (Flags & SymbolRef::SF_Common) {
355 // Add the common symbols to a list. We'll allocate them all below.
357 Check(I->getSize(Size));
361 if (CommonSize != 0) {
362 RWSectionSizes.push_back(CommonSize);
365 // Compute the required allocation space for each different type of sections
366 // (code, read-only data, read-write data) assuming that all sections are
367 // allocated with the max alignment. Note that we cannot compute with the
368 // individual alignments of the sections, because then the required size
369 // depends on the order, in which the sections are allocated.
370 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
371 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
372 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
375 // compute stub buffer size for the given section
376 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
377 const SectionRef &Section) {
378 unsigned StubSize = getMaxStubSize();
382 // FIXME: this is an inefficient way to handle this. We should computed the
383 // necessary section allocation size in loadObject by walking all the sections
385 unsigned StubBufSize = 0;
386 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
388 section_iterator RelSecI = SI->getRelocatedSection();
389 if (!(RelSecI == Section))
392 for (const RelocationRef &Reloc : SI->relocations()) {
394 StubBufSize += StubSize;
398 // Get section data size and alignment
399 uint64_t DataSize = Section.getSize();
400 uint64_t Alignment64 = Section.getAlignment();
402 // Add stubbuf size alignment
403 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
404 unsigned StubAlignment = getStubAlignment();
405 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
406 if (StubAlignment > EndAlignment)
407 StubBufSize += StubAlignment - EndAlignment;
411 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
412 unsigned Size) const {
414 if (IsTargetLittleEndian) {
417 Result = (Result << 8) | *Src--;
420 Result = (Result << 8) | *Src++;
425 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
426 unsigned Size) const {
427 if (IsTargetLittleEndian) {
429 *Dst++ = Value & 0xFF;
435 *Dst-- = Value & 0xFF;
441 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
442 CommonSymbolList &CommonSymbols) {
443 if (CommonSymbols.empty())
446 uint64_t CommonSize = 0;
447 CommonSymbolList SymbolsToAllocate;
449 DEBUG(dbgs() << "Processing common symbols...\n");
451 for (const auto &Sym : CommonSymbols) {
453 Check(Sym.getName(Name));
455 // Skip common symbols already elsewhere.
456 if (GlobalSymbolTable.count(Name) ||
457 MemMgr->getSymbolAddressInLogicalDylib(Name)) {
458 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
465 Check(Sym.getAlignment(Align));
466 Check(Sym.getSize(Size));
468 CommonSize += Align + Size;
469 SymbolsToAllocate.push_back(Sym);
472 // Allocate memory for the section
473 unsigned SectionID = Sections.size();
474 uint8_t *Addr = MemMgr->allocateDataSection(CommonSize, sizeof(void *),
475 SectionID, StringRef(), false);
477 report_fatal_error("Unable to allocate memory for common symbols!");
479 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
480 memset(Addr, 0, CommonSize);
482 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
483 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
485 // Assign the address of each symbol
486 for (auto &Sym : SymbolsToAllocate) {
490 Check(Sym.getAlignment(Align));
491 Check(Sym.getSize(Size));
492 Check(Sym.getName(Name));
494 // This symbol has an alignment requirement.
495 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
497 Offset += AlignOffset;
499 uint32_t Flags = Sym.getFlags();
500 SymbolInfo::Visibility Vis =
501 (Flags & SymbolRef::SF_Exported) ?
502 SymbolInfo::Default : SymbolInfo::Hidden;
503 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
504 << format("%p", Addr) << "\n");
505 GlobalSymbolTable[Name] = SymbolInfo(SectionID, Offset, Vis);
511 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
512 const SectionRef &Section, bool IsCode) {
515 Check(Section.getContents(data));
516 uint64_t Alignment64 = Section.getAlignment();
518 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
519 unsigned PaddingSize = 0;
520 unsigned StubBufSize = 0;
522 bool IsRequired = isRequiredForExecution(Section);
523 bool IsVirtual = Section.isVirtual();
524 bool IsZeroInit = isZeroInit(Section);
525 bool IsReadOnly = isReadOnlyData(Section);
526 uint64_t DataSize = Section.getSize();
527 Check(Section.getName(Name));
529 StubBufSize = computeSectionStubBufSize(Obj, Section);
531 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
532 // with zeroes added at the end. For MachO objects, this section has a
533 // slightly different name, so this won't have any effect for MachO objects.
534 if (Name == ".eh_frame")
538 unsigned SectionID = Sections.size();
540 const char *pData = nullptr;
542 // Some sections, such as debug info, don't need to be loaded for execution.
543 // Leave those where they are.
545 Allocate = DataSize + PaddingSize + StubBufSize;
546 Addr = IsCode ? MemMgr->allocateCodeSection(Allocate, Alignment, SectionID,
548 : MemMgr->allocateDataSection(Allocate, Alignment, SectionID,
551 report_fatal_error("Unable to allocate section memory!");
553 // Virtual sections have no data in the object image, so leave pData = 0
557 // Zero-initialize or copy the data from the image
558 if (IsZeroInit || IsVirtual)
559 memset(Addr, 0, DataSize);
561 memcpy(Addr, pData, DataSize);
563 // Fill in any extra bytes we allocated for padding
564 if (PaddingSize != 0) {
565 memset(Addr + DataSize, 0, PaddingSize);
566 // Update the DataSize variable so that the stub offset is set correctly.
567 DataSize += PaddingSize;
570 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
571 << " obj addr: " << format("%p", pData)
572 << " new addr: " << format("%p", Addr)
573 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
574 << " Allocate: " << Allocate << "\n");
576 // Even if we didn't load the section, we need to record an entry for it
577 // to handle later processing (and by 'handle' I mean don't do anything
578 // with these sections).
581 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
582 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
583 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
584 << " Allocate: " << Allocate << "\n");
587 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
590 Checker->registerSection(Obj.getFileName(), SectionID);
595 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
596 const SectionRef &Section,
598 ObjSectionToIDMap &LocalSections) {
600 unsigned SectionID = 0;
601 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
602 if (i != LocalSections.end())
603 SectionID = i->second;
605 SectionID = emitSection(Obj, Section, IsCode);
606 LocalSections[Section] = SectionID;
611 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
612 unsigned SectionID) {
613 Relocations[SectionID].push_back(RE);
616 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
617 StringRef SymbolName) {
618 // Relocation by symbol. If the symbol is found in the global symbol table,
619 // create an appropriate section relocation. Otherwise, add it to
620 // ExternalSymbolRelocations.
621 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
622 if (Loc == GlobalSymbolTable.end()) {
623 ExternalSymbolRelocations[SymbolName].push_back(RE);
625 // Copy the RE since we want to modify its addend.
626 RelocationEntry RECopy = RE;
627 const auto &SymInfo = Loc->second;
628 RECopy.Addend += SymInfo.getOffset();
629 Relocations[SymInfo.getSectionID()].push_back(RECopy);
633 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
634 unsigned AbiVariant) {
635 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
636 // This stub has to be able to access the full address space,
637 // since symbol lookup won't necessarily find a handy, in-range,
638 // PLT stub for functions which could be anywhere.
639 // Stub can use ip0 (== x16) to calculate address
640 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
641 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
642 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
643 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
644 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
647 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
648 // TODO: There is only ARM far stub now. We should add the Thumb stub,
649 // and stubs for branches Thumb - ARM and ARM - Thumb.
650 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
652 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
653 // 0: 3c190000 lui t9,%hi(addr).
654 // 4: 27390000 addiu t9,t9,%lo(addr).
655 // 8: 03200008 jr t9.
657 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
658 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
660 writeBytesUnaligned(LuiT9Instr, Addr, 4);
661 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
662 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
663 writeBytesUnaligned(NopInstr, Addr+12, 4);
665 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
666 // Depending on which version of the ELF ABI is in use, we need to
667 // generate one of two variants of the stub. They both start with
668 // the same sequence to load the target address into r12.
669 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
670 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
671 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
672 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
673 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
674 if (AbiVariant == 2) {
675 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
676 // The address is already in r12 as required by the ABI. Branch to it.
677 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
678 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
679 writeInt32BE(Addr+28, 0x4E800420); // bctr
681 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
682 // Load the function address on r11 and sets it to control register. Also
683 // loads the function TOC in r2 and environment pointer to r11.
684 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
685 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
686 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
687 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
688 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
689 writeInt32BE(Addr+40, 0x4E800420); // bctr
692 } else if (Arch == Triple::systemz) {
693 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
694 writeInt16BE(Addr+2, 0x0000);
695 writeInt16BE(Addr+4, 0x0004);
696 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
697 // 8-byte address stored at Addr + 8
699 } else if (Arch == Triple::x86_64) {
701 *(Addr+1) = 0x25; // rip
702 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
703 } else if (Arch == Triple::x86) {
704 *Addr = 0xE9; // 32-bit pc-relative jump.
709 // Assign an address to a symbol name and resolve all the relocations
710 // associated with it.
711 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
713 // The address to use for relocation resolution is not
714 // the address of the local section buffer. We must be doing
715 // a remote execution environment of some sort. Relocations can't
716 // be applied until all the sections have been moved. The client must
717 // trigger this with a call to MCJIT::finalize() or
718 // RuntimeDyld::resolveRelocations().
720 // Addr is a uint64_t because we can't assume the pointer width
721 // of the target is the same as that of the host. Just use a generic
722 // "big enough" type.
723 DEBUG(dbgs() << "Reassigning address for section "
724 << SectionID << " (" << Sections[SectionID].Name << "): "
725 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
726 << format("0x%016" PRIx64, Addr) << "\n");
727 Sections[SectionID].LoadAddress = Addr;
730 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
732 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
733 const RelocationEntry &RE = Relocs[i];
734 // Ignore relocations for sections that were not loaded
735 if (Sections[RE.SectionID].Address == nullptr)
737 resolveRelocation(RE, Value);
741 void RuntimeDyldImpl::resolveExternalSymbols() {
742 while (!ExternalSymbolRelocations.empty()) {
743 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
745 StringRef Name = i->first();
746 if (Name.size() == 0) {
747 // This is an absolute symbol, use an address of zero.
748 DEBUG(dbgs() << "Resolving absolute relocations."
750 RelocationList &Relocs = i->second;
751 resolveRelocationList(Relocs, 0);
754 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
755 if (Loc == GlobalSymbolTable.end()) {
756 // This is an external symbol, try to get its address from
758 Addr = MemMgr->getSymbolAddress(Name.data());
759 // The call to getSymbolAddress may have caused additional modules to
760 // be loaded, which may have added new entries to the
761 // ExternalSymbolRelocations map. Consquently, we need to update our
762 // iterator. This is also why retrieval of the relocation list
763 // associated with this symbol is deferred until below this point.
764 // New entries may have been added to the relocation list.
765 i = ExternalSymbolRelocations.find(Name);
767 // We found the symbol in our global table. It was probably in a
768 // Module that we loaded previously.
769 const auto &SymInfo = Loc->second;
770 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
774 // FIXME: Implement error handling that doesn't kill the host program!
776 report_fatal_error("Program used external function '" + Name +
777 "' which could not be resolved!");
779 updateGOTEntries(Name, Addr);
780 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
781 << format("0x%lx", Addr) << "\n");
782 // This list may have been updated when we called getSymbolAddress, so
783 // don't change this code to get the list earlier.
784 RelocationList &Relocs = i->second;
785 resolveRelocationList(Relocs, Addr);
788 ExternalSymbolRelocations.erase(i);
792 //===----------------------------------------------------------------------===//
793 // RuntimeDyld class implementation
795 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
796 StringRef SectionName) const {
797 for (unsigned I = BeginIdx; I != EndIdx; ++I)
798 if (RTDyld.Sections[I].Name == SectionName)
799 return RTDyld.Sections[I].LoadAddress;
804 RuntimeDyld::RuntimeDyld(RTDyldMemoryManager *mm) {
805 // FIXME: There's a potential issue lurking here if a single instance of
806 // RuntimeDyld is used to load multiple objects. The current implementation
807 // associates a single memory manager with a RuntimeDyld instance. Even
808 // though the public class spawns a new 'impl' instance for each load,
809 // they share a single memory manager. This can become a problem when page
810 // permissions are applied.
813 ProcessAllSections = false;
817 RuntimeDyld::~RuntimeDyld() {}
819 static std::unique_ptr<RuntimeDyldELF>
820 createRuntimeDyldELF(RTDyldMemoryManager *MM, bool ProcessAllSections,
821 RuntimeDyldCheckerImpl *Checker) {
822 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM));
823 Dyld->setProcessAllSections(ProcessAllSections);
824 Dyld->setRuntimeDyldChecker(Checker);
828 static std::unique_ptr<RuntimeDyldMachO>
829 createRuntimeDyldMachO(Triple::ArchType Arch, RTDyldMemoryManager *MM,
830 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
831 std::unique_ptr<RuntimeDyldMachO> Dyld(RuntimeDyldMachO::create(Arch, MM));
832 Dyld->setProcessAllSections(ProcessAllSections);
833 Dyld->setRuntimeDyldChecker(Checker);
837 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
838 RuntimeDyld::loadObject(const ObjectFile &Obj) {
841 Dyld = createRuntimeDyldELF(MM, ProcessAllSections, Checker);
842 else if (Obj.isMachO())
843 Dyld = createRuntimeDyldMachO(
844 static_cast<Triple::ArchType>(Obj.getArch()), MM,
845 ProcessAllSections, Checker);
847 report_fatal_error("Incompatible object format!");
850 if (!Dyld->isCompatibleFile(Obj))
851 report_fatal_error("Incompatible object format!");
853 return Dyld->loadObject(Obj);
856 void *RuntimeDyld::getSymbolAddress(StringRef Name) const {
859 return Dyld->getSymbolAddress(Name);
862 uint64_t RuntimeDyld::getSymbolLoadAddress(StringRef Name) const {
865 return Dyld->getSymbolLoadAddress(Name);
868 uint64_t RuntimeDyld::getExportedSymbolLoadAddress(StringRef Name) const {
871 return Dyld->getExportedSymbolLoadAddress(Name);
874 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
876 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
877 Dyld->reassignSectionAddress(SectionID, Addr);
880 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
881 uint64_t TargetAddress) {
882 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
885 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
887 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
889 void RuntimeDyld::registerEHFrames() {
891 Dyld->registerEHFrames();
894 void RuntimeDyld::deregisterEHFrames() {
896 Dyld->deregisterEHFrames();
899 } // end namespace llvm