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 "RuntimeDyldCOFF.h"
17 #include "RuntimeDyldELF.h"
18 #include "RuntimeDyldImpl.h"
19 #include "RuntimeDyldMachO.h"
20 #include "llvm/Object/ELFObjectFile.h"
21 #include "llvm/Object/COFF.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 LoadedObjectInfo's vtables to this file.
34 void RuntimeDyld::LoadedObjectInfo::anchor() {}
38 void RuntimeDyldImpl::registerEHFrames() {}
40 void RuntimeDyldImpl::deregisterEHFrames() {}
43 static void dumpSectionMemory(const SectionEntry &S, StringRef State) {
44 dbgs() << "----- Contents of section " << S.getName() << " " << State
47 if (S.getAddress() == nullptr) {
48 dbgs() << "\n <section not emitted>\n";
52 const unsigned ColsPerRow = 16;
54 uint8_t *DataAddr = S.getAddress();
55 uint64_t LoadAddr = S.getLoadAddress();
57 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
58 unsigned BytesRemaining = S.getSize();
61 dbgs() << "\n" << format("0x%016" PRIx64,
62 LoadAddr & ~(uint64_t)(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 // Print out the sections prior to relocation.
88 for (int i = 0, e = Sections.size(); i != e; ++i)
89 dumpSectionMemory(Sections[i], "before relocations");
92 // First, resolve relocations associated with external symbols.
93 resolveExternalSymbols();
95 // Iterate over all outstanding relocations
96 for (auto it = Relocations.begin(), e = Relocations.end(); it != e; ++it) {
97 // The Section here (Sections[i]) refers to the section in which the
98 // symbol for the relocation is located. The SectionID in the relocation
99 // entry provides the section to which the relocation will be applied.
100 int Idx = it->getFirst();
101 uint64_t Addr = Sections[Idx].getLoadAddress();
102 DEBUG(dbgs() << "Resolving relocations Section #" << Idx << "\t"
103 << format("%p", (uintptr_t)Addr) << "\n");
104 resolveRelocationList(it->getSecond(), Addr);
108 // Print out sections after relocation.
110 for (int i = 0, e = Sections.size(); i != e; ++i)
111 dumpSectionMemory(Sections[i], "after relocations");
116 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
117 uint64_t TargetAddress) {
118 MutexGuard locked(lock);
119 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
120 if (Sections[i].getAddress() == LocalAddress) {
121 reassignSectionAddress(i, TargetAddress);
125 llvm_unreachable("Attempting to remap address of unknown section!");
128 static std::error_code getOffset(const SymbolRef &Sym, SectionRef Sec,
130 ErrorOr<uint64_t> AddressOrErr = Sym.getAddress();
131 if (std::error_code EC = AddressOrErr.getError())
133 Result = *AddressOrErr - Sec.getAddress();
134 return std::error_code();
137 RuntimeDyldImpl::ObjSectionToIDMap
138 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
139 MutexGuard locked(lock);
141 // Save information about our target
142 Arch = (Triple::ArchType)Obj.getArch();
143 IsTargetLittleEndian = Obj.isLittleEndian();
146 // Compute the memory size required to load all sections to be loaded
147 // and pass this information to the memory manager
148 if (MemMgr.needsToReserveAllocationSpace()) {
149 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
150 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
151 MemMgr.reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
154 // Used sections from the object file
155 ObjSectionToIDMap LocalSections;
157 // Common symbols requiring allocation, with their sizes and alignments
158 CommonSymbolList CommonSymbols;
161 DEBUG(dbgs() << "Parse symbols:\n");
162 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
164 uint32_t Flags = I->getFlags();
166 if (Flags & SymbolRef::SF_Common)
167 CommonSymbols.push_back(*I);
169 object::SymbolRef::Type SymType = I->getType();
172 ErrorOr<StringRef> NameOrErr = I->getName();
173 Check(NameOrErr.getError());
174 StringRef Name = *NameOrErr;
176 // Compute JIT symbol flags.
177 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
178 if (Flags & SymbolRef::SF_Weak)
179 RTDyldSymFlags |= JITSymbolFlags::Weak;
180 if (Flags & SymbolRef::SF_Exported)
181 RTDyldSymFlags |= JITSymbolFlags::Exported;
183 if (Flags & SymbolRef::SF_Absolute &&
184 SymType != object::SymbolRef::ST_File) {
185 auto Addr = I->getAddress();
186 Check(Addr.getError());
187 uint64_t SectOffset = *Addr;
188 unsigned SectionID = AbsoluteSymbolSection;
190 DEBUG(dbgs() << "\tType: " << SymType << " (absolute) Name: " << Name
191 << " SID: " << SectionID << " Offset: "
192 << format("%p", (uintptr_t)SectOffset)
193 << " flags: " << Flags << "\n");
194 GlobalSymbolTable[Name] =
195 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
196 } else if (SymType == object::SymbolRef::ST_Function ||
197 SymType == object::SymbolRef::ST_Data ||
198 SymType == object::SymbolRef::ST_Unknown ||
199 SymType == object::SymbolRef::ST_Other) {
201 ErrorOr<section_iterator> SIOrErr = I->getSection();
202 Check(SIOrErr.getError());
203 section_iterator SI = *SIOrErr;
204 if (SI == Obj.section_end())
206 // Get symbol offset.
208 Check(getOffset(*I, *SI, SectOffset));
209 bool IsCode = SI->isText();
210 unsigned SectionID = findOrEmitSection(Obj, *SI, IsCode, LocalSections);
212 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
213 << " SID: " << SectionID << " Offset: "
214 << format("%p", (uintptr_t)SectOffset)
215 << " flags: " << Flags << "\n");
216 GlobalSymbolTable[Name] =
217 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
222 // Allocate common symbols
223 emitCommonSymbols(Obj, CommonSymbols);
225 // Parse and process relocations
226 DEBUG(dbgs() << "Parse relocations:\n");
227 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
229 unsigned SectionID = 0;
231 section_iterator RelocatedSection = SI->getRelocatedSection();
233 if (RelocatedSection == SE)
236 relocation_iterator I = SI->relocation_begin();
237 relocation_iterator E = SI->relocation_end();
239 if (I == E && !ProcessAllSections)
242 bool IsCode = RelocatedSection->isText();
244 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
245 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
248 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
250 // If there is an attached checker, notify it about the stubs for this
251 // section so that they can be verified.
253 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
256 // Give the subclasses a chance to tie-up any loose ends.
257 finalizeLoad(Obj, LocalSections);
259 // for (auto E : LocalSections)
260 // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
262 return LocalSections;
265 // A helper method for computeTotalAllocSize.
266 // Computes the memory size required to allocate sections with the given sizes,
267 // assuming that all sections are allocated with the given alignment
269 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
270 uint64_t Alignment) {
271 uint64_t TotalSize = 0;
272 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
273 uint64_t AlignedSize =
274 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
275 TotalSize += AlignedSize;
280 static bool isRequiredForExecution(const SectionRef Section) {
281 const ObjectFile *Obj = Section.getObject();
282 if (isa<object::ELFObjectFileBase>(Obj))
283 return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
284 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
285 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
286 // Avoid loading zero-sized COFF sections.
287 // In PE files, VirtualSize gives the section size, and SizeOfRawData
288 // may be zero for sections with content. In Obj files, SizeOfRawData
289 // gives the section size, and VirtualSize is always zero. Hence
290 // the need to check for both cases below.
291 bool HasContent = (CoffSection->VirtualSize > 0)
292 || (CoffSection->SizeOfRawData > 0);
293 bool IsDiscardable = CoffSection->Characteristics &
294 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
295 return HasContent && !IsDiscardable;
298 assert(isa<MachOObjectFile>(Obj));
302 static bool isReadOnlyData(const SectionRef Section) {
303 const ObjectFile *Obj = Section.getObject();
304 if (isa<object::ELFObjectFileBase>(Obj))
305 return !(ELFSectionRef(Section).getFlags() &
306 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
307 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
308 return ((COFFObj->getCOFFSection(Section)->Characteristics &
309 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
310 | COFF::IMAGE_SCN_MEM_READ
311 | COFF::IMAGE_SCN_MEM_WRITE))
313 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
314 | COFF::IMAGE_SCN_MEM_READ));
316 assert(isa<MachOObjectFile>(Obj));
320 static bool isZeroInit(const SectionRef Section) {
321 const ObjectFile *Obj = Section.getObject();
322 if (isa<object::ELFObjectFileBase>(Obj))
323 return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
324 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
325 return COFFObj->getCOFFSection(Section)->Characteristics &
326 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
328 auto *MachO = cast<MachOObjectFile>(Obj);
329 unsigned SectionType = MachO->getSectionType(Section);
330 return SectionType == MachO::S_ZEROFILL ||
331 SectionType == MachO::S_GB_ZEROFILL;
334 // Compute an upper bound of the memory size that is required to load all
336 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
338 uint64_t &DataSizeRO,
339 uint64_t &DataSizeRW) {
340 // Compute the size of all sections required for execution
341 std::vector<uint64_t> CodeSectionSizes;
342 std::vector<uint64_t> ROSectionSizes;
343 std::vector<uint64_t> RWSectionSizes;
344 uint64_t MaxAlignment = sizeof(void *);
346 // Collect sizes of all sections to be loaded;
347 // also determine the max alignment of all sections
348 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
350 const SectionRef &Section = *SI;
352 bool IsRequired = isRequiredForExecution(Section);
354 // Consider only the sections that are required to be loaded for execution
357 uint64_t DataSize = Section.getSize();
358 uint64_t Alignment64 = Section.getAlignment();
359 bool IsCode = Section.isText();
360 bool IsReadOnly = isReadOnlyData(Section);
361 Check(Section.getName(Name));
362 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
364 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
365 uint64_t SectionSize = DataSize + StubBufSize;
367 // The .eh_frame section (at least on Linux) needs an extra four bytes
369 // with zeroes added at the end. For MachO objects, this section has a
370 // slightly different name, so this won't have any effect for MachO
372 if (Name == ".eh_frame")
379 CodeSectionSizes.push_back(SectionSize);
380 } else if (IsReadOnly) {
381 ROSectionSizes.push_back(SectionSize);
383 RWSectionSizes.push_back(SectionSize);
386 // update the max alignment
387 if (Alignment > MaxAlignment) {
388 MaxAlignment = Alignment;
393 // Compute the size of all common symbols
394 uint64_t CommonSize = 0;
395 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
397 uint32_t Flags = I->getFlags();
398 if (Flags & SymbolRef::SF_Common) {
399 // Add the common symbols to a list. We'll allocate them all below.
400 uint64_t Size = I->getCommonSize();
404 if (CommonSize != 0) {
405 RWSectionSizes.push_back(CommonSize);
408 // Compute the required allocation space for each different type of sections
409 // (code, read-only data, read-write data) assuming that all sections are
410 // allocated with the max alignment. Note that we cannot compute with the
411 // individual alignments of the sections, because then the required size
412 // depends on the order, in which the sections are allocated.
413 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
414 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
415 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
418 // compute stub buffer size for the given section
419 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
420 const SectionRef &Section) {
421 unsigned StubSize = getMaxStubSize();
425 // FIXME: this is an inefficient way to handle this. We should computed the
426 // necessary section allocation size in loadObject by walking all the sections
428 unsigned StubBufSize = 0;
429 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
431 section_iterator RelSecI = SI->getRelocatedSection();
432 if (!(RelSecI == Section))
435 for (const RelocationRef &Reloc : SI->relocations()) {
437 StubBufSize += StubSize;
441 // Get section data size and alignment
442 uint64_t DataSize = Section.getSize();
443 uint64_t Alignment64 = Section.getAlignment();
445 // Add stubbuf size alignment
446 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
447 unsigned StubAlignment = getStubAlignment();
448 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
449 if (StubAlignment > EndAlignment)
450 StubBufSize += StubAlignment - EndAlignment;
454 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
455 unsigned Size) const {
457 if (IsTargetLittleEndian) {
460 Result = (Result << 8) | *Src--;
463 Result = (Result << 8) | *Src++;
468 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
469 unsigned Size) const {
470 if (IsTargetLittleEndian) {
472 *Dst++ = Value & 0xFF;
478 *Dst-- = Value & 0xFF;
484 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
485 CommonSymbolList &CommonSymbols) {
486 if (CommonSymbols.empty())
489 uint64_t CommonSize = 0;
490 CommonSymbolList SymbolsToAllocate;
492 DEBUG(dbgs() << "Processing common symbols...\n");
494 for (const auto &Sym : CommonSymbols) {
495 ErrorOr<StringRef> NameOrErr = Sym.getName();
496 Check(NameOrErr.getError());
497 StringRef Name = *NameOrErr;
499 // Skip common symbols already elsewhere.
500 if (GlobalSymbolTable.count(Name) ||
501 Resolver.findSymbolInLogicalDylib(Name)) {
502 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
507 uint32_t Align = Sym.getAlignment();
508 uint64_t Size = Sym.getCommonSize();
510 CommonSize += Align + Size;
511 SymbolsToAllocate.push_back(Sym);
514 // Allocate memory for the section
515 unsigned SectionID = Sections.size();
516 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
517 SectionID, StringRef(), false);
519 report_fatal_error("Unable to allocate memory for common symbols!");
521 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
522 memset(Addr, 0, CommonSize);
524 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
525 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
527 // Assign the address of each symbol
528 for (auto &Sym : SymbolsToAllocate) {
529 uint32_t Align = Sym.getAlignment();
530 uint64_t Size = Sym.getCommonSize();
531 ErrorOr<StringRef> NameOrErr = Sym.getName();
532 Check(NameOrErr.getError());
533 StringRef Name = *NameOrErr;
535 // This symbol has an alignment requirement.
536 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
538 Offset += AlignOffset;
540 uint32_t Flags = Sym.getFlags();
541 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
542 if (Flags & SymbolRef::SF_Weak)
543 RTDyldSymFlags |= JITSymbolFlags::Weak;
544 if (Flags & SymbolRef::SF_Exported)
545 RTDyldSymFlags |= JITSymbolFlags::Exported;
546 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
547 << format("%p", Addr) << "\n");
548 GlobalSymbolTable[Name] =
549 SymbolTableEntry(SectionID, Offset, RTDyldSymFlags);
555 Checker->registerSection(Obj.getFileName(), SectionID);
558 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
559 const SectionRef &Section, bool IsCode) {
562 uint64_t Alignment64 = Section.getAlignment();
564 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
565 unsigned PaddingSize = 0;
566 unsigned StubBufSize = 0;
568 bool IsRequired = isRequiredForExecution(Section);
569 bool IsVirtual = Section.isVirtual();
570 bool IsZeroInit = isZeroInit(Section);
571 bool IsReadOnly = isReadOnlyData(Section);
572 uint64_t DataSize = Section.getSize();
573 Check(Section.getName(Name));
575 StubBufSize = computeSectionStubBufSize(Obj, Section);
577 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
578 // with zeroes added at the end. For MachO objects, this section has a
579 // slightly different name, so this won't have any effect for MachO objects.
580 if (Name == ".eh_frame")
584 unsigned SectionID = Sections.size();
586 const char *pData = nullptr;
588 // If this section contains any bits (i.e. isn't a virtual or bss section),
589 // grab a reference to them.
590 if (!IsVirtual && !IsZeroInit) {
591 // In either case, set the location of the unrelocated section in memory,
592 // since we still process relocations for it even if we're not applying them.
593 Check(Section.getContents(data));
597 // Code section alignment needs to be at least as high as stub alignment or
598 // padding calculations may by incorrect when the section is remapped to a
601 Alignment = std::max(Alignment, getStubAlignment());
603 // Some sections, such as debug info, don't need to be loaded for execution.
604 // Leave those where they are.
606 Allocate = DataSize + PaddingSize + StubBufSize;
609 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
611 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
614 report_fatal_error("Unable to allocate section memory!");
616 // Zero-initialize or copy the data from the image
617 if (IsZeroInit || IsVirtual)
618 memset(Addr, 0, DataSize);
620 memcpy(Addr, pData, DataSize);
622 // Fill in any extra bytes we allocated for padding
623 if (PaddingSize != 0) {
624 memset(Addr + DataSize, 0, PaddingSize);
625 // Update the DataSize variable so that the stub offset is set correctly.
626 DataSize += PaddingSize;
629 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
630 << " obj addr: " << format("%p", pData)
631 << " new addr: " << format("%p", Addr)
632 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
633 << " Allocate: " << Allocate << "\n");
635 // Even if we didn't load the section, we need to record an entry for it
636 // to handle later processing (and by 'handle' I mean don't do anything
637 // with these sections).
640 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
641 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
642 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
643 << " Allocate: " << Allocate << "\n");
646 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
649 Checker->registerSection(Obj.getFileName(), SectionID);
654 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
655 const SectionRef &Section,
657 ObjSectionToIDMap &LocalSections) {
659 unsigned SectionID = 0;
660 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
661 if (i != LocalSections.end())
662 SectionID = i->second;
664 SectionID = emitSection(Obj, Section, IsCode);
665 LocalSections[Section] = SectionID;
670 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
671 unsigned SectionID) {
672 Relocations[SectionID].push_back(RE);
675 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
676 StringRef SymbolName) {
677 // Relocation by symbol. If the symbol is found in the global symbol table,
678 // create an appropriate section relocation. Otherwise, add it to
679 // ExternalSymbolRelocations.
680 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
681 if (Loc == GlobalSymbolTable.end()) {
682 ExternalSymbolRelocations[SymbolName].push_back(RE);
684 // Copy the RE since we want to modify its addend.
685 RelocationEntry RECopy = RE;
686 const auto &SymInfo = Loc->second;
687 RECopy.Addend += SymInfo.getOffset();
688 Relocations[SymInfo.getSectionID()].push_back(RECopy);
692 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
693 unsigned AbiVariant) {
694 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
695 // This stub has to be able to access the full address space,
696 // since symbol lookup won't necessarily find a handy, in-range,
697 // PLT stub for functions which could be anywhere.
698 // Stub can use ip0 (== x16) to calculate address
699 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
700 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
701 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
702 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
703 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
706 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
707 // TODO: There is only ARM far stub now. We should add the Thumb stub,
708 // and stubs for branches Thumb - ARM and ARM - Thumb.
709 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
711 } else if (IsMipsO32ABI) {
712 // 0: 3c190000 lui t9,%hi(addr).
713 // 4: 27390000 addiu t9,t9,%lo(addr).
714 // 8: 03200008 jr t9.
716 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
717 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
719 writeBytesUnaligned(LuiT9Instr, Addr, 4);
720 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
721 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
722 writeBytesUnaligned(NopInstr, Addr+12, 4);
724 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
725 // Depending on which version of the ELF ABI is in use, we need to
726 // generate one of two variants of the stub. They both start with
727 // the same sequence to load the target address into r12.
728 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
729 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
730 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
731 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
732 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
733 if (AbiVariant == 2) {
734 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
735 // The address is already in r12 as required by the ABI. Branch to it.
736 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
737 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
738 writeInt32BE(Addr+28, 0x4E800420); // bctr
740 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
741 // Load the function address on r11 and sets it to control register. Also
742 // loads the function TOC in r2 and environment pointer to r11.
743 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
744 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
745 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
746 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
747 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
748 writeInt32BE(Addr+40, 0x4E800420); // bctr
751 } else if (Arch == Triple::systemz) {
752 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
753 writeInt16BE(Addr+2, 0x0000);
754 writeInt16BE(Addr+4, 0x0004);
755 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
756 // 8-byte address stored at Addr + 8
758 } else if (Arch == Triple::x86_64) {
760 *(Addr+1) = 0x25; // rip
761 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
762 } else if (Arch == Triple::x86) {
763 *Addr = 0xE9; // 32-bit pc-relative jump.
768 // Assign an address to a symbol name and resolve all the relocations
769 // associated with it.
770 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
772 // The address to use for relocation resolution is not
773 // the address of the local section buffer. We must be doing
774 // a remote execution environment of some sort. Relocations can't
775 // be applied until all the sections have been moved. The client must
776 // trigger this with a call to MCJIT::finalize() or
777 // RuntimeDyld::resolveRelocations().
779 // Addr is a uint64_t because we can't assume the pointer width
780 // of the target is the same as that of the host. Just use a generic
781 // "big enough" type.
782 DEBUG(dbgs() << "Reassigning address for section " << SectionID << " ("
783 << Sections[SectionID].getName() << "): "
784 << format("0x%016" PRIx64, Sections[SectionID].getLoadAddress())
785 << " -> " << format("0x%016" PRIx64, Addr) << "\n");
786 Sections[SectionID].setLoadAddress(Addr);
789 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
791 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
792 const RelocationEntry &RE = Relocs[i];
793 // Ignore relocations for sections that were not loaded
794 if (Sections[RE.SectionID].getAddress() == nullptr)
796 resolveRelocation(RE, Value);
800 void RuntimeDyldImpl::resolveExternalSymbols() {
801 while (!ExternalSymbolRelocations.empty()) {
802 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
804 StringRef Name = i->first();
805 if (Name.size() == 0) {
806 // This is an absolute symbol, use an address of zero.
807 DEBUG(dbgs() << "Resolving absolute relocations."
809 RelocationList &Relocs = i->second;
810 resolveRelocationList(Relocs, 0);
813 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
814 if (Loc == GlobalSymbolTable.end()) {
815 // This is an external symbol, try to get its address from the symbol
817 Addr = Resolver.findSymbol(Name.data()).getAddress();
818 // The call to getSymbolAddress may have caused additional modules to
819 // be loaded, which may have added new entries to the
820 // ExternalSymbolRelocations map. Consquently, we need to update our
821 // iterator. This is also why retrieval of the relocation list
822 // associated with this symbol is deferred until below this point.
823 // New entries may have been added to the relocation list.
824 i = ExternalSymbolRelocations.find(Name);
826 // We found the symbol in our global table. It was probably in a
827 // Module that we loaded previously.
828 const auto &SymInfo = Loc->second;
829 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
833 // FIXME: Implement error handling that doesn't kill the host program!
835 report_fatal_error("Program used external function '" + Name +
836 "' which could not be resolved!");
838 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
839 // manually and we shouldn't resolve its relocations.
840 if (Addr != UINT64_MAX) {
841 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
842 << format("0x%lx", Addr) << "\n");
843 // This list may have been updated when we called getSymbolAddress, so
844 // don't change this code to get the list earlier.
845 RelocationList &Relocs = i->second;
846 resolveRelocationList(Relocs, Addr);
850 ExternalSymbolRelocations.erase(i);
854 //===----------------------------------------------------------------------===//
855 // RuntimeDyld class implementation
857 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
858 const object::SectionRef &Sec) const {
860 auto I = ObjSecToIDMap.find(Sec);
861 if (I != ObjSecToIDMap.end())
862 return RTDyld.Sections[I->second].getLoadAddress();
867 void RuntimeDyld::MemoryManager::anchor() {}
868 void RuntimeDyld::SymbolResolver::anchor() {}
870 RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
871 RuntimeDyld::SymbolResolver &Resolver)
872 : MemMgr(MemMgr), Resolver(Resolver) {
873 // FIXME: There's a potential issue lurking here if a single instance of
874 // RuntimeDyld is used to load multiple objects. The current implementation
875 // associates a single memory manager with a RuntimeDyld instance. Even
876 // though the public class spawns a new 'impl' instance for each load,
877 // they share a single memory manager. This can become a problem when page
878 // permissions are applied.
880 ProcessAllSections = false;
884 RuntimeDyld::~RuntimeDyld() {}
886 static std::unique_ptr<RuntimeDyldCOFF>
887 createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
888 RuntimeDyld::SymbolResolver &Resolver,
889 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
890 std::unique_ptr<RuntimeDyldCOFF> Dyld =
891 RuntimeDyldCOFF::create(Arch, MM, Resolver);
892 Dyld->setProcessAllSections(ProcessAllSections);
893 Dyld->setRuntimeDyldChecker(Checker);
897 static std::unique_ptr<RuntimeDyldELF>
898 createRuntimeDyldELF(RuntimeDyld::MemoryManager &MM,
899 RuntimeDyld::SymbolResolver &Resolver,
900 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
901 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver));
902 Dyld->setProcessAllSections(ProcessAllSections);
903 Dyld->setRuntimeDyldChecker(Checker);
907 static std::unique_ptr<RuntimeDyldMachO>
908 createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
909 RuntimeDyld::SymbolResolver &Resolver,
910 bool ProcessAllSections,
911 RuntimeDyldCheckerImpl *Checker) {
912 std::unique_ptr<RuntimeDyldMachO> Dyld =
913 RuntimeDyldMachO::create(Arch, MM, Resolver);
914 Dyld->setProcessAllSections(ProcessAllSections);
915 Dyld->setRuntimeDyldChecker(Checker);
919 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
920 RuntimeDyld::loadObject(const ObjectFile &Obj) {
923 Dyld = createRuntimeDyldELF(MemMgr, Resolver, ProcessAllSections, Checker);
924 else if (Obj.isMachO())
925 Dyld = createRuntimeDyldMachO(
926 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
927 ProcessAllSections, Checker);
928 else if (Obj.isCOFF())
929 Dyld = createRuntimeDyldCOFF(
930 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
931 ProcessAllSections, Checker);
933 report_fatal_error("Incompatible object format!");
936 if (!Dyld->isCompatibleFile(Obj))
937 report_fatal_error("Incompatible object format!");
939 return Dyld->loadObject(Obj);
942 void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
945 return Dyld->getSymbolLocalAddress(Name);
948 RuntimeDyld::SymbolInfo RuntimeDyld::getSymbol(StringRef Name) const {
951 return Dyld->getSymbol(Name);
954 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
956 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
957 Dyld->reassignSectionAddress(SectionID, Addr);
960 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
961 uint64_t TargetAddress) {
962 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
965 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
967 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
969 void RuntimeDyld::registerEHFrames() {
971 Dyld->registerEHFrames();
974 void RuntimeDyld::deregisterEHFrames() {
976 Dyld->deregisterEHFrames();
979 } // end namespace llvm