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.
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->second, 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, RODataSize = 0, RWDataSize = 0;
150 uint32_t CodeAlign = 1, RODataAlign = 1, RWDataAlign = 1;
151 computeTotalAllocSize(Obj, CodeSize, CodeAlign, RODataSize, RODataAlign,
152 RWDataSize, RWDataAlign);
153 MemMgr.reserveAllocationSpace(CodeSize, CodeAlign, RODataSize, RODataAlign,
154 RWDataSize, RWDataAlign);
157 // Used sections from the object file
158 ObjSectionToIDMap LocalSections;
160 // Common symbols requiring allocation, with their sizes and alignments
161 CommonSymbolList CommonSymbols;
164 DEBUG(dbgs() << "Parse symbols:\n");
165 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
167 uint32_t Flags = I->getFlags();
169 if (Flags & SymbolRef::SF_Common)
170 CommonSymbols.push_back(*I);
172 object::SymbolRef::Type SymType = I->getType();
175 ErrorOr<StringRef> NameOrErr = I->getName();
176 Check(NameOrErr.getError());
177 StringRef Name = *NameOrErr;
179 // Compute JIT symbol flags.
180 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
181 if (Flags & SymbolRef::SF_Weak)
182 RTDyldSymFlags |= JITSymbolFlags::Weak;
183 if (Flags & SymbolRef::SF_Exported)
184 RTDyldSymFlags |= JITSymbolFlags::Exported;
186 if (Flags & SymbolRef::SF_Absolute &&
187 SymType != object::SymbolRef::ST_File) {
188 auto Addr = I->getAddress();
189 Check(Addr.getError());
190 uint64_t SectOffset = *Addr;
191 unsigned SectionID = AbsoluteSymbolSection;
193 DEBUG(dbgs() << "\tType: " << SymType << " (absolute) Name: " << Name
194 << " SID: " << SectionID << " Offset: "
195 << format("%p", (uintptr_t)SectOffset)
196 << " flags: " << Flags << "\n");
197 GlobalSymbolTable[Name] =
198 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
199 } else if (SymType == object::SymbolRef::ST_Function ||
200 SymType == object::SymbolRef::ST_Data ||
201 SymType == object::SymbolRef::ST_Unknown ||
202 SymType == object::SymbolRef::ST_Other) {
204 ErrorOr<section_iterator> SIOrErr = I->getSection();
205 Check(SIOrErr.getError());
206 section_iterator SI = *SIOrErr;
207 if (SI == Obj.section_end())
209 // Get symbol offset.
211 Check(getOffset(*I, *SI, SectOffset));
212 bool IsCode = SI->isText();
213 unsigned SectionID = findOrEmitSection(Obj, *SI, IsCode, LocalSections);
215 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
216 << " SID: " << SectionID << " Offset: "
217 << format("%p", (uintptr_t)SectOffset)
218 << " flags: " << Flags << "\n");
219 GlobalSymbolTable[Name] =
220 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
225 // Allocate common symbols
226 emitCommonSymbols(Obj, CommonSymbols);
228 // Parse and process relocations
229 DEBUG(dbgs() << "Parse relocations:\n");
230 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
232 unsigned SectionID = 0;
234 section_iterator RelocatedSection = SI->getRelocatedSection();
236 if (RelocatedSection == SE)
239 relocation_iterator I = SI->relocation_begin();
240 relocation_iterator E = SI->relocation_end();
242 if (I == E && !ProcessAllSections)
245 bool IsCode = RelocatedSection->isText();
247 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
248 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
251 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
253 // If there is an attached checker, notify it about the stubs for this
254 // section so that they can be verified.
256 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
259 // Give the subclasses a chance to tie-up any loose ends.
260 finalizeLoad(Obj, LocalSections);
262 // for (auto E : LocalSections)
263 // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
265 return LocalSections;
268 // A helper method for computeTotalAllocSize.
269 // Computes the memory size required to allocate sections with the given sizes,
270 // assuming that all sections are allocated with the given alignment
272 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
273 uint64_t Alignment) {
274 uint64_t TotalSize = 0;
275 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
276 uint64_t AlignedSize =
277 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
278 TotalSize += AlignedSize;
283 static bool isRequiredForExecution(const SectionRef Section) {
284 const ObjectFile *Obj = Section.getObject();
285 if (isa<object::ELFObjectFileBase>(Obj))
286 return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
287 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
288 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
289 // Avoid loading zero-sized COFF sections.
290 // In PE files, VirtualSize gives the section size, and SizeOfRawData
291 // may be zero for sections with content. In Obj files, SizeOfRawData
292 // gives the section size, and VirtualSize is always zero. Hence
293 // the need to check for both cases below.
294 bool HasContent = (CoffSection->VirtualSize > 0)
295 || (CoffSection->SizeOfRawData > 0);
296 bool IsDiscardable = CoffSection->Characteristics &
297 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
298 return HasContent && !IsDiscardable;
301 assert(isa<MachOObjectFile>(Obj));
305 static bool isReadOnlyData(const SectionRef Section) {
306 const ObjectFile *Obj = Section.getObject();
307 if (isa<object::ELFObjectFileBase>(Obj))
308 return !(ELFSectionRef(Section).getFlags() &
309 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
310 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
311 return ((COFFObj->getCOFFSection(Section)->Characteristics &
312 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
313 | COFF::IMAGE_SCN_MEM_READ
314 | COFF::IMAGE_SCN_MEM_WRITE))
316 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
317 | COFF::IMAGE_SCN_MEM_READ));
319 assert(isa<MachOObjectFile>(Obj));
323 static bool isZeroInit(const SectionRef Section) {
324 const ObjectFile *Obj = Section.getObject();
325 if (isa<object::ELFObjectFileBase>(Obj))
326 return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
327 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
328 return COFFObj->getCOFFSection(Section)->Characteristics &
329 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
331 auto *MachO = cast<MachOObjectFile>(Obj);
332 unsigned SectionType = MachO->getSectionType(Section);
333 return SectionType == MachO::S_ZEROFILL ||
334 SectionType == MachO::S_GB_ZEROFILL;
337 // Compute an upper bound of the memory size that is required to load all
339 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
342 uint64_t &RODataSize,
343 uint32_t &RODataAlign,
344 uint64_t &RWDataSize,
345 uint32_t &RWDataAlign) {
346 // Compute the size of all sections required for execution
347 std::vector<uint64_t> CodeSectionSizes;
348 std::vector<uint64_t> ROSectionSizes;
349 std::vector<uint64_t> RWSectionSizes;
351 // Collect sizes of all sections to be loaded;
352 // also determine the max alignment of all sections
353 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
355 const SectionRef &Section = *SI;
357 bool IsRequired = isRequiredForExecution(Section);
359 // Consider only the sections that are required to be loaded for execution
362 uint64_t DataSize = Section.getSize();
363 uint64_t Alignment64 = Section.getAlignment();
364 bool IsCode = Section.isText();
365 bool IsReadOnly = isReadOnlyData(Section);
366 Check(Section.getName(Name));
367 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
369 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
370 uint64_t SectionSize = DataSize + StubBufSize;
372 // The .eh_frame section (at least on Linux) needs an extra four bytes
374 // with zeroes added at the end. For MachO objects, this section has a
375 // slightly different name, so this won't have any effect for MachO
377 if (Name == ".eh_frame")
384 CodeAlign = std::max(CodeAlign, Alignment);
385 CodeSectionSizes.push_back(SectionSize);
386 } else if (IsReadOnly) {
387 RODataAlign = std::max(RODataAlign, Alignment);
388 ROSectionSizes.push_back(SectionSize);
390 RWDataAlign = std::max(RWDataAlign, Alignment);
391 RWSectionSizes.push_back(SectionSize);
396 // Compute the size of all common symbols
397 uint64_t CommonSize = 0;
398 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
400 uint32_t Flags = I->getFlags();
401 if (Flags & SymbolRef::SF_Common) {
402 // Add the common symbols to a list. We'll allocate them all below.
403 uint64_t Size = I->getCommonSize();
407 if (CommonSize != 0) {
408 RWSectionSizes.push_back(CommonSize);
411 // Compute the required allocation space for each different type of sections
412 // (code, read-only data, read-write data) assuming that all sections are
413 // allocated with the max alignment. Note that we cannot compute with the
414 // individual alignments of the sections, because then the required size
415 // depends on the order, in which the sections are allocated.
416 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, CodeAlign);
417 RODataSize = computeAllocationSizeForSections(ROSectionSizes, RODataAlign);
418 RWDataSize = computeAllocationSizeForSections(RWSectionSizes, RWDataAlign);
421 // compute stub buffer size for the given section
422 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
423 const SectionRef &Section) {
424 unsigned StubSize = getMaxStubSize();
428 // FIXME: this is an inefficient way to handle this. We should computed the
429 // necessary section allocation size in loadObject by walking all the sections
431 unsigned StubBufSize = 0;
432 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
434 section_iterator RelSecI = SI->getRelocatedSection();
435 if (!(RelSecI == Section))
438 for (const RelocationRef &Reloc : SI->relocations())
439 if (relocationNeedsStub(Reloc))
440 StubBufSize += StubSize;
443 // Get section data size and alignment
444 uint64_t DataSize = Section.getSize();
445 uint64_t Alignment64 = Section.getAlignment();
447 // Add stubbuf size alignment
448 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
449 unsigned StubAlignment = getStubAlignment();
450 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
451 if (StubAlignment > EndAlignment)
452 StubBufSize += StubAlignment - EndAlignment;
456 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
457 unsigned Size) const {
459 if (IsTargetLittleEndian) {
462 Result = (Result << 8) | *Src--;
465 Result = (Result << 8) | *Src++;
470 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
471 unsigned Size) const {
472 if (IsTargetLittleEndian) {
474 *Dst++ = Value & 0xFF;
480 *Dst-- = Value & 0xFF;
486 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
487 CommonSymbolList &CommonSymbols) {
488 if (CommonSymbols.empty())
491 uint64_t CommonSize = 0;
492 CommonSymbolList SymbolsToAllocate;
494 DEBUG(dbgs() << "Processing common symbols...\n");
496 for (const auto &Sym : CommonSymbols) {
497 ErrorOr<StringRef> NameOrErr = Sym.getName();
498 Check(NameOrErr.getError());
499 StringRef Name = *NameOrErr;
501 // Skip common symbols already elsewhere.
502 if (GlobalSymbolTable.count(Name) ||
503 Resolver.findSymbolInLogicalDylib(Name)) {
504 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
509 uint32_t Align = Sym.getAlignment();
510 uint64_t Size = Sym.getCommonSize();
512 CommonSize += Align + Size;
513 SymbolsToAllocate.push_back(Sym);
516 // Allocate memory for the section
517 unsigned SectionID = Sections.size();
518 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
519 SectionID, StringRef(), false);
521 report_fatal_error("Unable to allocate memory for common symbols!");
524 SectionEntry("<common symbols>", Addr, CommonSize, CommonSize, 0));
525 memset(Addr, 0, CommonSize);
527 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
528 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
530 // Assign the address of each symbol
531 for (auto &Sym : SymbolsToAllocate) {
532 uint32_t Align = Sym.getAlignment();
533 uint64_t Size = Sym.getCommonSize();
534 ErrorOr<StringRef> NameOrErr = Sym.getName();
535 Check(NameOrErr.getError());
536 StringRef Name = *NameOrErr;
538 // This symbol has an alignment requirement.
539 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
541 Offset += AlignOffset;
543 uint32_t Flags = Sym.getFlags();
544 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
545 if (Flags & SymbolRef::SF_Weak)
546 RTDyldSymFlags |= JITSymbolFlags::Weak;
547 if (Flags & SymbolRef::SF_Exported)
548 RTDyldSymFlags |= JITSymbolFlags::Exported;
549 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
550 << format("%p", Addr) << "\n");
551 GlobalSymbolTable[Name] =
552 SymbolTableEntry(SectionID, Offset, RTDyldSymFlags);
558 Checker->registerSection(Obj.getFileName(), SectionID);
561 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
562 const SectionRef &Section, bool IsCode) {
565 uint64_t Alignment64 = Section.getAlignment();
567 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
568 unsigned PaddingSize = 0;
569 unsigned StubBufSize = 0;
571 bool IsRequired = isRequiredForExecution(Section);
572 bool IsVirtual = Section.isVirtual();
573 bool IsZeroInit = isZeroInit(Section);
574 bool IsReadOnly = isReadOnlyData(Section);
575 uint64_t DataSize = Section.getSize();
576 Check(Section.getName(Name));
578 StubBufSize = computeSectionStubBufSize(Obj, Section);
580 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
581 // with zeroes added at the end. For MachO objects, this section has a
582 // slightly different name, so this won't have any effect for MachO objects.
583 if (Name == ".eh_frame")
587 unsigned SectionID = Sections.size();
589 const char *pData = nullptr;
591 // If this section contains any bits (i.e. isn't a virtual or bss section),
592 // grab a reference to them.
593 if (!IsVirtual && !IsZeroInit) {
594 // In either case, set the location of the unrelocated section in memory,
595 // since we still process relocations for it even if we're not applying them.
596 Check(Section.getContents(data));
600 // Code section alignment needs to be at least as high as stub alignment or
601 // padding calculations may by incorrect when the section is remapped to a
604 Alignment = std::max(Alignment, getStubAlignment());
606 // Some sections, such as debug info, don't need to be loaded for execution.
607 // Leave those where they are.
609 Allocate = DataSize + PaddingSize + StubBufSize;
612 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
614 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
617 report_fatal_error("Unable to allocate section memory!");
619 // Zero-initialize or copy the data from the image
620 if (IsZeroInit || IsVirtual)
621 memset(Addr, 0, DataSize);
623 memcpy(Addr, pData, DataSize);
625 // Fill in any extra bytes we allocated for padding
626 if (PaddingSize != 0) {
627 memset(Addr + DataSize, 0, PaddingSize);
628 // Update the DataSize variable so that the stub offset is set correctly.
629 DataSize += PaddingSize;
632 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
633 << " obj addr: " << format("%p", pData)
634 << " new addr: " << format("%p", Addr)
635 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
636 << " Allocate: " << Allocate << "\n");
638 // Even if we didn't load the section, we need to record an entry for it
639 // to handle later processing (and by 'handle' I mean don't do anything
640 // with these sections).
643 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
644 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
645 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
646 << " Allocate: " << Allocate << "\n");
650 SectionEntry(Name, Addr, DataSize, Allocate, (uintptr_t)pData));
653 Checker->registerSection(Obj.getFileName(), SectionID);
658 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
659 const SectionRef &Section,
661 ObjSectionToIDMap &LocalSections) {
663 unsigned SectionID = 0;
664 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
665 if (i != LocalSections.end())
666 SectionID = i->second;
668 SectionID = emitSection(Obj, Section, IsCode);
669 LocalSections[Section] = SectionID;
674 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
675 unsigned SectionID) {
676 Relocations[SectionID].push_back(RE);
679 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
680 StringRef SymbolName) {
681 // Relocation by symbol. If the symbol is found in the global symbol table,
682 // create an appropriate section relocation. Otherwise, add it to
683 // ExternalSymbolRelocations.
684 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
685 if (Loc == GlobalSymbolTable.end()) {
686 ExternalSymbolRelocations[SymbolName].push_back(RE);
688 // Copy the RE since we want to modify its addend.
689 RelocationEntry RECopy = RE;
690 const auto &SymInfo = Loc->second;
691 RECopy.Addend += SymInfo.getOffset();
692 Relocations[SymInfo.getSectionID()].push_back(RECopy);
696 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
697 unsigned AbiVariant) {
698 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
699 // This stub has to be able to access the full address space,
700 // since symbol lookup won't necessarily find a handy, in-range,
701 // PLT stub for functions which could be anywhere.
702 // Stub can use ip0 (== x16) to calculate address
703 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
704 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
705 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
706 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
707 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
710 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
711 // TODO: There is only ARM far stub now. We should add the Thumb stub,
712 // and stubs for branches Thumb - ARM and ARM - Thumb.
713 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
715 } else if (IsMipsO32ABI) {
716 // 0: 3c190000 lui t9,%hi(addr).
717 // 4: 27390000 addiu t9,t9,%lo(addr).
718 // 8: 03200008 jr t9.
720 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
721 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
723 writeBytesUnaligned(LuiT9Instr, Addr, 4);
724 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
725 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
726 writeBytesUnaligned(NopInstr, Addr+12, 4);
728 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
729 // Depending on which version of the ELF ABI is in use, we need to
730 // generate one of two variants of the stub. They both start with
731 // the same sequence to load the target address into r12.
732 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
733 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
734 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
735 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
736 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
737 if (AbiVariant == 2) {
738 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
739 // The address is already in r12 as required by the ABI. Branch to it.
740 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
741 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
742 writeInt32BE(Addr+28, 0x4E800420); // bctr
744 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
745 // Load the function address on r11 and sets it to control register. Also
746 // loads the function TOC in r2 and environment pointer to r11.
747 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
748 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
749 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
750 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
751 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
752 writeInt32BE(Addr+40, 0x4E800420); // bctr
755 } else if (Arch == Triple::systemz) {
756 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
757 writeInt16BE(Addr+2, 0x0000);
758 writeInt16BE(Addr+4, 0x0004);
759 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
760 // 8-byte address stored at Addr + 8
762 } else if (Arch == Triple::x86_64) {
764 *(Addr+1) = 0x25; // rip
765 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
766 } else if (Arch == Triple::x86) {
767 *Addr = 0xE9; // 32-bit pc-relative jump.
772 // Assign an address to a symbol name and resolve all the relocations
773 // associated with it.
774 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
776 // The address to use for relocation resolution is not
777 // the address of the local section buffer. We must be doing
778 // a remote execution environment of some sort. Relocations can't
779 // be applied until all the sections have been moved. The client must
780 // trigger this with a call to MCJIT::finalize() or
781 // RuntimeDyld::resolveRelocations().
783 // Addr is a uint64_t because we can't assume the pointer width
784 // of the target is the same as that of the host. Just use a generic
785 // "big enough" type.
786 DEBUG(dbgs() << "Reassigning address for section " << SectionID << " ("
787 << Sections[SectionID].getName() << "): "
788 << format("0x%016" PRIx64, Sections[SectionID].getLoadAddress())
789 << " -> " << format("0x%016" PRIx64, Addr) << "\n");
790 Sections[SectionID].setLoadAddress(Addr);
793 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
795 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
796 const RelocationEntry &RE = Relocs[i];
797 // Ignore relocations for sections that were not loaded
798 if (Sections[RE.SectionID].getAddress() == nullptr)
800 resolveRelocation(RE, Value);
804 void RuntimeDyldImpl::resolveExternalSymbols() {
805 while (!ExternalSymbolRelocations.empty()) {
806 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
808 StringRef Name = i->first();
809 if (Name.size() == 0) {
810 // This is an absolute symbol, use an address of zero.
811 DEBUG(dbgs() << "Resolving absolute relocations."
813 RelocationList &Relocs = i->second;
814 resolveRelocationList(Relocs, 0);
817 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
818 if (Loc == GlobalSymbolTable.end()) {
819 // This is an external symbol, try to get its address from the symbol
821 Addr = Resolver.findSymbol(Name.data()).getAddress();
822 // The call to getSymbolAddress may have caused additional modules to
823 // be loaded, which may have added new entries to the
824 // ExternalSymbolRelocations map. Consquently, we need to update our
825 // iterator. This is also why retrieval of the relocation list
826 // associated with this symbol is deferred until below this point.
827 // New entries may have been added to the relocation list.
828 i = ExternalSymbolRelocations.find(Name);
830 // We found the symbol in our global table. It was probably in a
831 // Module that we loaded previously.
832 const auto &SymInfo = Loc->second;
833 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
837 // FIXME: Implement error handling that doesn't kill the host program!
839 report_fatal_error("Program used external function '" + Name +
840 "' which could not be resolved!");
842 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
843 // manually and we shouldn't resolve its relocations.
844 if (Addr != UINT64_MAX) {
845 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
846 << format("0x%lx", Addr) << "\n");
847 // This list may have been updated when we called getSymbolAddress, so
848 // don't change this code to get the list earlier.
849 RelocationList &Relocs = i->second;
850 resolveRelocationList(Relocs, Addr);
854 ExternalSymbolRelocations.erase(i);
858 //===----------------------------------------------------------------------===//
859 // RuntimeDyld class implementation
861 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
862 const object::SectionRef &Sec) const {
864 auto I = ObjSecToIDMap.find(Sec);
865 if (I != ObjSecToIDMap.end())
866 return RTDyld.Sections[I->second].getLoadAddress();
871 void RuntimeDyld::MemoryManager::anchor() {}
872 void RuntimeDyld::SymbolResolver::anchor() {}
874 RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
875 RuntimeDyld::SymbolResolver &Resolver)
876 : MemMgr(MemMgr), Resolver(Resolver) {
877 // FIXME: There's a potential issue lurking here if a single instance of
878 // RuntimeDyld is used to load multiple objects. The current implementation
879 // associates a single memory manager with a RuntimeDyld instance. Even
880 // though the public class spawns a new 'impl' instance for each load,
881 // they share a single memory manager. This can become a problem when page
882 // permissions are applied.
884 ProcessAllSections = false;
888 RuntimeDyld::~RuntimeDyld() {}
890 static std::unique_ptr<RuntimeDyldCOFF>
891 createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
892 RuntimeDyld::SymbolResolver &Resolver,
893 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
894 std::unique_ptr<RuntimeDyldCOFF> Dyld =
895 RuntimeDyldCOFF::create(Arch, MM, Resolver);
896 Dyld->setProcessAllSections(ProcessAllSections);
897 Dyld->setRuntimeDyldChecker(Checker);
901 static std::unique_ptr<RuntimeDyldELF>
902 createRuntimeDyldELF(RuntimeDyld::MemoryManager &MM,
903 RuntimeDyld::SymbolResolver &Resolver,
904 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
905 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver));
906 Dyld->setProcessAllSections(ProcessAllSections);
907 Dyld->setRuntimeDyldChecker(Checker);
911 static std::unique_ptr<RuntimeDyldMachO>
912 createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
913 RuntimeDyld::SymbolResolver &Resolver,
914 bool ProcessAllSections,
915 RuntimeDyldCheckerImpl *Checker) {
916 std::unique_ptr<RuntimeDyldMachO> Dyld =
917 RuntimeDyldMachO::create(Arch, MM, Resolver);
918 Dyld->setProcessAllSections(ProcessAllSections);
919 Dyld->setRuntimeDyldChecker(Checker);
923 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
924 RuntimeDyld::loadObject(const ObjectFile &Obj) {
927 Dyld = createRuntimeDyldELF(MemMgr, Resolver, ProcessAllSections, Checker);
928 else if (Obj.isMachO())
929 Dyld = createRuntimeDyldMachO(
930 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
931 ProcessAllSections, Checker);
932 else if (Obj.isCOFF())
933 Dyld = createRuntimeDyldCOFF(
934 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
935 ProcessAllSections, Checker);
937 report_fatal_error("Incompatible object format!");
940 if (!Dyld->isCompatibleFile(Obj))
941 report_fatal_error("Incompatible object format!");
943 auto LoadedObjInfo = Dyld->loadObject(Obj);
944 MemMgr.notifyObjectLoaded(*this, Obj);
945 return LoadedObjInfo;
948 void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
951 return Dyld->getSymbolLocalAddress(Name);
954 RuntimeDyld::SymbolInfo RuntimeDyld::getSymbol(StringRef Name) const {
957 return Dyld->getSymbol(Name);
960 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
962 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
963 Dyld->reassignSectionAddress(SectionID, Addr);
966 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
967 uint64_t TargetAddress) {
968 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
971 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
973 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
975 void RuntimeDyld::finalizeWithMemoryManagerLocking() {
976 bool MemoryFinalizationLocked = MemMgr.FinalizationLocked;
977 MemMgr.FinalizationLocked = true;
978 resolveRelocations();
980 if (!MemoryFinalizationLocked) {
981 MemMgr.finalizeMemory();
982 MemMgr.FinalizationLocked = false;
986 void RuntimeDyld::registerEHFrames() {
988 Dyld->registerEHFrames();
991 void RuntimeDyld::deregisterEHFrames() {
993 Dyld->deregisterEHFrames();
996 } // end namespace llvm