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.Name << " " << State << " -----";
46 if (S.Address == nullptr) {
47 dbgs() << "\n <section not emitted>\n";
51 const unsigned ColsPerRow = 16;
53 uint8_t *DataAddr = S.Address;
54 uint64_t LoadAddr = S.LoadAddress;
56 unsigned StartPadding = LoadAddr & (ColsPerRow - 1);
57 unsigned BytesRemaining = S.Size;
60 dbgs() << "\n" << format("0x%016" PRIx64,
61 LoadAddr & ~(uint64_t)(ColsPerRow - 1)) << ":";
62 while (StartPadding--)
66 while (BytesRemaining > 0) {
67 if ((LoadAddr & (ColsPerRow - 1)) == 0)
68 dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":";
70 dbgs() << " " << format("%02x", *DataAddr);
81 // Resolve the relocations for all symbols we currently know about.
82 void RuntimeDyldImpl::resolveRelocations() {
83 MutexGuard locked(lock);
85 // First, resolve relocations associated with external symbols.
86 resolveExternalSymbols();
88 // Just iterate over the sections we have and resolve all the relocations
89 // in them. Gross overkill, but it gets the job done.
90 for (int i = 0, e = Sections.size(); i != e; ++i) {
91 // The Section here (Sections[i]) refers to the section in which the
92 // symbol for the relocation is located. The SectionID in the relocation
93 // entry provides the section to which the relocation will be applied.
94 uint64_t Addr = Sections[i].LoadAddress;
95 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"
96 << format("%p", (uintptr_t)Addr) << "\n");
97 DEBUG(dumpSectionMemory(Sections[i], "before relocations"));
98 resolveRelocationList(Relocations[i], Addr);
99 DEBUG(dumpSectionMemory(Sections[i], "after relocations"));
100 Relocations.erase(i);
104 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
105 uint64_t TargetAddress) {
106 MutexGuard locked(lock);
107 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
108 if (Sections[i].Address == LocalAddress) {
109 reassignSectionAddress(i, TargetAddress);
113 llvm_unreachable("Attempting to remap address of unknown section!");
116 static std::error_code getOffset(const SymbolRef &Sym, SectionRef Sec,
118 ErrorOr<uint64_t> AddressOrErr = Sym.getAddress();
119 if (std::error_code EC = AddressOrErr.getError())
121 Result = *AddressOrErr - Sec.getAddress();
122 return std::error_code();
125 std::pair<unsigned, unsigned>
126 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
127 MutexGuard locked(lock);
129 // Grab the first Section ID. We'll use this later to construct the underlying
130 // range for the returned LoadedObjectInfo.
131 unsigned SectionsAddedBeginIdx = Sections.size();
133 // Save information about our target
134 Arch = (Triple::ArchType)Obj.getArch();
135 IsTargetLittleEndian = Obj.isLittleEndian();
138 // Compute the memory size required to load all sections to be loaded
139 // and pass this information to the memory manager
140 if (MemMgr.needsToReserveAllocationSpace()) {
141 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
142 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
143 MemMgr.reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
146 // Used sections from the object file
147 ObjSectionToIDMap LocalSections;
149 // Common symbols requiring allocation, with their sizes and alignments
150 CommonSymbolList CommonSymbols;
153 DEBUG(dbgs() << "Parse symbols:\n");
154 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
156 uint32_t Flags = I->getFlags();
158 bool IsCommon = Flags & SymbolRef::SF_Common;
160 CommonSymbols.push_back(*I);
162 object::SymbolRef::Type SymType = I->getType();
164 if (SymType == object::SymbolRef::ST_Function ||
165 SymType == object::SymbolRef::ST_Data ||
166 SymType == object::SymbolRef::ST_Unknown) {
168 ErrorOr<StringRef> NameOrErr = I->getName();
169 Check(NameOrErr.getError());
170 StringRef Name = *NameOrErr;
171 section_iterator SI = Obj.section_end();
172 Check(I->getSection(SI));
173 if (SI == Obj.section_end())
176 Check(getOffset(*I, *SI, SectOffset));
177 StringRef SectionData;
178 Check(SI->getContents(SectionData));
179 bool IsCode = SI->isText();
181 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
182 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
183 << " SID: " << SectionID << " Offset: "
184 << format("%p", (uintptr_t)SectOffset)
185 << " flags: " << Flags << "\n");
186 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
187 if (Flags & SymbolRef::SF_Weak)
188 RTDyldSymFlags |= JITSymbolFlags::Weak;
189 if (Flags & SymbolRef::SF_Exported)
190 RTDyldSymFlags |= JITSymbolFlags::Exported;
191 GlobalSymbolTable[Name] =
192 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
197 // Allocate common symbols
198 emitCommonSymbols(Obj, CommonSymbols);
200 // Parse and process relocations
201 DEBUG(dbgs() << "Parse relocations:\n");
202 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
204 unsigned SectionID = 0;
206 section_iterator RelocatedSection = SI->getRelocatedSection();
208 if (RelocatedSection == SE)
211 relocation_iterator I = SI->relocation_begin();
212 relocation_iterator E = SI->relocation_end();
214 if (I == E && !ProcessAllSections)
217 bool IsCode = RelocatedSection->isText();
219 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
220 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
223 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
225 // If there is an attached checker, notify it about the stubs for this
226 // section so that they can be verified.
228 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
231 // Give the subclasses a chance to tie-up any loose ends.
232 finalizeLoad(Obj, LocalSections);
234 unsigned SectionsAddedEndIdx = Sections.size();
236 return std::make_pair(SectionsAddedBeginIdx, SectionsAddedEndIdx);
239 // A helper method for computeTotalAllocSize.
240 // Computes the memory size required to allocate sections with the given sizes,
241 // assuming that all sections are allocated with the given alignment
243 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
244 uint64_t Alignment) {
245 uint64_t TotalSize = 0;
246 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
247 uint64_t AlignedSize =
248 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
249 TotalSize += AlignedSize;
254 static bool isRequiredForExecution(const SectionRef Section) {
255 const ObjectFile *Obj = Section.getObject();
256 if (isa<object::ELFObjectFileBase>(Obj))
257 return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
258 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
259 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
260 // Avoid loading zero-sized COFF sections.
261 // In PE files, VirtualSize gives the section size, and SizeOfRawData
262 // may be zero for sections with content. In Obj files, SizeOfRawData
263 // gives the section size, and VirtualSize is always zero. Hence
264 // the need to check for both cases below.
265 bool HasContent = (CoffSection->VirtualSize > 0)
266 || (CoffSection->SizeOfRawData > 0);
267 bool IsDiscardable = CoffSection->Characteristics &
268 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
269 return HasContent && !IsDiscardable;
272 assert(isa<MachOObjectFile>(Obj));
276 static bool isReadOnlyData(const SectionRef Section) {
277 const ObjectFile *Obj = Section.getObject();
278 if (isa<object::ELFObjectFileBase>(Obj))
279 return !(ELFSectionRef(Section).getFlags() &
280 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
281 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
282 return ((COFFObj->getCOFFSection(Section)->Characteristics &
283 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
284 | COFF::IMAGE_SCN_MEM_READ
285 | COFF::IMAGE_SCN_MEM_WRITE))
287 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
288 | COFF::IMAGE_SCN_MEM_READ));
290 assert(isa<MachOObjectFile>(Obj));
294 static bool isZeroInit(const SectionRef Section) {
295 const ObjectFile *Obj = Section.getObject();
296 if (isa<object::ELFObjectFileBase>(Obj))
297 return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
298 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
299 return COFFObj->getCOFFSection(Section)->Characteristics &
300 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
302 auto *MachO = cast<MachOObjectFile>(Obj);
303 unsigned SectionType = MachO->getSectionType(Section);
304 return SectionType == MachO::S_ZEROFILL ||
305 SectionType == MachO::S_GB_ZEROFILL;
308 // Compute an upper bound of the memory size that is required to load all
310 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
312 uint64_t &DataSizeRO,
313 uint64_t &DataSizeRW) {
314 // Compute the size of all sections required for execution
315 std::vector<uint64_t> CodeSectionSizes;
316 std::vector<uint64_t> ROSectionSizes;
317 std::vector<uint64_t> RWSectionSizes;
318 uint64_t MaxAlignment = sizeof(void *);
320 // Collect sizes of all sections to be loaded;
321 // also determine the max alignment of all sections
322 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
324 const SectionRef &Section = *SI;
326 bool IsRequired = isRequiredForExecution(Section);
328 // Consider only the sections that are required to be loaded for execution
331 uint64_t DataSize = Section.getSize();
332 uint64_t Alignment64 = Section.getAlignment();
333 bool IsCode = Section.isText();
334 bool IsReadOnly = isReadOnlyData(Section);
335 Check(Section.getName(Name));
336 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
338 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
339 uint64_t SectionSize = DataSize + StubBufSize;
341 // The .eh_frame section (at least on Linux) needs an extra four bytes
343 // with zeroes added at the end. For MachO objects, this section has a
344 // slightly different name, so this won't have any effect for MachO
346 if (Name == ".eh_frame")
353 CodeSectionSizes.push_back(SectionSize);
354 } else if (IsReadOnly) {
355 ROSectionSizes.push_back(SectionSize);
357 RWSectionSizes.push_back(SectionSize);
360 // update the max alignment
361 if (Alignment > MaxAlignment) {
362 MaxAlignment = Alignment;
367 // Compute the size of all common symbols
368 uint64_t CommonSize = 0;
369 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
371 uint32_t Flags = I->getFlags();
372 if (Flags & SymbolRef::SF_Common) {
373 // Add the common symbols to a list. We'll allocate them all below.
374 uint64_t Size = I->getCommonSize();
378 if (CommonSize != 0) {
379 RWSectionSizes.push_back(CommonSize);
382 // Compute the required allocation space for each different type of sections
383 // (code, read-only data, read-write data) assuming that all sections are
384 // allocated with the max alignment. Note that we cannot compute with the
385 // individual alignments of the sections, because then the required size
386 // depends on the order, in which the sections are allocated.
387 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
388 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
389 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
392 // compute stub buffer size for the given section
393 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
394 const SectionRef &Section) {
395 unsigned StubSize = getMaxStubSize();
399 // FIXME: this is an inefficient way to handle this. We should computed the
400 // necessary section allocation size in loadObject by walking all the sections
402 unsigned StubBufSize = 0;
403 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
405 section_iterator RelSecI = SI->getRelocatedSection();
406 if (!(RelSecI == Section))
409 for (const RelocationRef &Reloc : SI->relocations()) {
411 StubBufSize += StubSize;
415 // Get section data size and alignment
416 uint64_t DataSize = Section.getSize();
417 uint64_t Alignment64 = Section.getAlignment();
419 // Add stubbuf size alignment
420 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
421 unsigned StubAlignment = getStubAlignment();
422 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
423 if (StubAlignment > EndAlignment)
424 StubBufSize += StubAlignment - EndAlignment;
428 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
429 unsigned Size) const {
431 if (IsTargetLittleEndian) {
434 Result = (Result << 8) | *Src--;
437 Result = (Result << 8) | *Src++;
442 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
443 unsigned Size) const {
444 if (IsTargetLittleEndian) {
446 *Dst++ = Value & 0xFF;
452 *Dst-- = Value & 0xFF;
458 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
459 CommonSymbolList &CommonSymbols) {
460 if (CommonSymbols.empty())
463 uint64_t CommonSize = 0;
464 CommonSymbolList SymbolsToAllocate;
466 DEBUG(dbgs() << "Processing common symbols...\n");
468 for (const auto &Sym : CommonSymbols) {
469 ErrorOr<StringRef> NameOrErr = Sym.getName();
470 Check(NameOrErr.getError());
471 StringRef Name = *NameOrErr;
473 // Skip common symbols already elsewhere.
474 if (GlobalSymbolTable.count(Name) ||
475 Resolver.findSymbolInLogicalDylib(Name)) {
476 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
481 uint32_t Align = Sym.getAlignment();
482 uint64_t Size = Sym.getCommonSize();
484 CommonSize += Align + Size;
485 SymbolsToAllocate.push_back(Sym);
488 // Allocate memory for the section
489 unsigned SectionID = Sections.size();
490 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
491 SectionID, StringRef(), false);
493 report_fatal_error("Unable to allocate memory for common symbols!");
495 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
496 memset(Addr, 0, CommonSize);
498 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
499 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
501 // Assign the address of each symbol
502 for (auto &Sym : SymbolsToAllocate) {
503 uint32_t Align = Sym.getAlignment();
504 uint64_t Size = Sym.getCommonSize();
505 ErrorOr<StringRef> NameOrErr = Sym.getName();
506 Check(NameOrErr.getError());
507 StringRef Name = *NameOrErr;
509 // This symbol has an alignment requirement.
510 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
512 Offset += AlignOffset;
514 uint32_t Flags = Sym.getFlags();
515 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
516 if (Flags & SymbolRef::SF_Weak)
517 RTDyldSymFlags |= JITSymbolFlags::Weak;
518 if (Flags & SymbolRef::SF_Exported)
519 RTDyldSymFlags |= JITSymbolFlags::Exported;
520 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
521 << format("%p", Addr) << "\n");
522 GlobalSymbolTable[Name] =
523 SymbolTableEntry(SectionID, Offset, RTDyldSymFlags);
529 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
530 const SectionRef &Section, bool IsCode) {
533 uint64_t Alignment64 = Section.getAlignment();
535 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
536 unsigned PaddingSize = 0;
537 unsigned StubBufSize = 0;
539 bool IsRequired = isRequiredForExecution(Section);
540 bool IsVirtual = Section.isVirtual();
541 bool IsZeroInit = isZeroInit(Section);
542 bool IsReadOnly = isReadOnlyData(Section);
543 uint64_t DataSize = Section.getSize();
544 Check(Section.getName(Name));
546 StubBufSize = computeSectionStubBufSize(Obj, Section);
548 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
549 // with zeroes added at the end. For MachO objects, this section has a
550 // slightly different name, so this won't have any effect for MachO objects.
551 if (Name == ".eh_frame")
555 unsigned SectionID = Sections.size();
557 const char *pData = nullptr;
559 // In either case, set the location of the unrelocated section in memory,
560 // since we still process relocations for it even if we're not applying them.
561 Check(Section.getContents(data));
562 // Virtual sections have no data in the object image, so leave pData = 0
566 // Some sections, such as debug info, don't need to be loaded for execution.
567 // Leave those where they are.
569 Allocate = DataSize + PaddingSize + StubBufSize;
572 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
574 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
577 report_fatal_error("Unable to allocate section memory!");
579 // Zero-initialize or copy the data from the image
580 if (IsZeroInit || IsVirtual)
581 memset(Addr, 0, DataSize);
583 memcpy(Addr, pData, DataSize);
585 // Fill in any extra bytes we allocated for padding
586 if (PaddingSize != 0) {
587 memset(Addr + DataSize, 0, PaddingSize);
588 // Update the DataSize variable so that the stub offset is set correctly.
589 DataSize += PaddingSize;
592 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
593 << " obj addr: " << format("%p", pData)
594 << " new addr: " << format("%p", Addr)
595 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
596 << " Allocate: " << Allocate << "\n");
598 // Even if we didn't load the section, we need to record an entry for it
599 // to handle later processing (and by 'handle' I mean don't do anything
600 // with these sections).
603 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
604 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
605 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
606 << " Allocate: " << Allocate << "\n");
609 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
612 Checker->registerSection(Obj.getFileName(), SectionID);
617 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
618 const SectionRef &Section,
620 ObjSectionToIDMap &LocalSections) {
622 unsigned SectionID = 0;
623 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
624 if (i != LocalSections.end())
625 SectionID = i->second;
627 SectionID = emitSection(Obj, Section, IsCode);
628 LocalSections[Section] = SectionID;
633 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
634 unsigned SectionID) {
635 Relocations[SectionID].push_back(RE);
638 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
639 StringRef SymbolName) {
640 // Relocation by symbol. If the symbol is found in the global symbol table,
641 // create an appropriate section relocation. Otherwise, add it to
642 // ExternalSymbolRelocations.
643 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
644 if (Loc == GlobalSymbolTable.end()) {
645 ExternalSymbolRelocations[SymbolName].push_back(RE);
647 // Copy the RE since we want to modify its addend.
648 RelocationEntry RECopy = RE;
649 const auto &SymInfo = Loc->second;
650 RECopy.Addend += SymInfo.getOffset();
651 Relocations[SymInfo.getSectionID()].push_back(RECopy);
655 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
656 unsigned AbiVariant) {
657 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
658 // This stub has to be able to access the full address space,
659 // since symbol lookup won't necessarily find a handy, in-range,
660 // PLT stub for functions which could be anywhere.
661 // Stub can use ip0 (== x16) to calculate address
662 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
663 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
664 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
665 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
666 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
669 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
670 // TODO: There is only ARM far stub now. We should add the Thumb stub,
671 // and stubs for branches Thumb - ARM and ARM - Thumb.
672 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
674 } else if (IsMipsO32ABI) {
675 // 0: 3c190000 lui t9,%hi(addr).
676 // 4: 27390000 addiu t9,t9,%lo(addr).
677 // 8: 03200008 jr t9.
679 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
680 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
682 writeBytesUnaligned(LuiT9Instr, Addr, 4);
683 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
684 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
685 writeBytesUnaligned(NopInstr, Addr+12, 4);
687 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
688 // Depending on which version of the ELF ABI is in use, we need to
689 // generate one of two variants of the stub. They both start with
690 // the same sequence to load the target address into r12.
691 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
692 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
693 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
694 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
695 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
696 if (AbiVariant == 2) {
697 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
698 // The address is already in r12 as required by the ABI. Branch to it.
699 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
700 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
701 writeInt32BE(Addr+28, 0x4E800420); // bctr
703 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
704 // Load the function address on r11 and sets it to control register. Also
705 // loads the function TOC in r2 and environment pointer to r11.
706 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
707 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
708 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
709 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
710 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
711 writeInt32BE(Addr+40, 0x4E800420); // bctr
714 } else if (Arch == Triple::systemz) {
715 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
716 writeInt16BE(Addr+2, 0x0000);
717 writeInt16BE(Addr+4, 0x0004);
718 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
719 // 8-byte address stored at Addr + 8
721 } else if (Arch == Triple::x86_64) {
723 *(Addr+1) = 0x25; // rip
724 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
725 } else if (Arch == Triple::x86) {
726 *Addr = 0xE9; // 32-bit pc-relative jump.
731 // Assign an address to a symbol name and resolve all the relocations
732 // associated with it.
733 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
735 // The address to use for relocation resolution is not
736 // the address of the local section buffer. We must be doing
737 // a remote execution environment of some sort. Relocations can't
738 // be applied until all the sections have been moved. The client must
739 // trigger this with a call to MCJIT::finalize() or
740 // RuntimeDyld::resolveRelocations().
742 // Addr is a uint64_t because we can't assume the pointer width
743 // of the target is the same as that of the host. Just use a generic
744 // "big enough" type.
745 DEBUG(dbgs() << "Reassigning address for section "
746 << SectionID << " (" << Sections[SectionID].Name << "): "
747 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
748 << format("0x%016" PRIx64, Addr) << "\n");
749 Sections[SectionID].LoadAddress = Addr;
752 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
754 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
755 const RelocationEntry &RE = Relocs[i];
756 // Ignore relocations for sections that were not loaded
757 if (Sections[RE.SectionID].Address == nullptr)
759 resolveRelocation(RE, Value);
763 void RuntimeDyldImpl::resolveExternalSymbols() {
764 while (!ExternalSymbolRelocations.empty()) {
765 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
767 StringRef Name = i->first();
768 if (Name.size() == 0) {
769 // This is an absolute symbol, use an address of zero.
770 DEBUG(dbgs() << "Resolving absolute relocations."
772 RelocationList &Relocs = i->second;
773 resolveRelocationList(Relocs, 0);
776 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
777 if (Loc == GlobalSymbolTable.end()) {
778 // This is an external symbol, try to get its address from the symbol
780 Addr = Resolver.findSymbol(Name.data()).getAddress();
781 // The call to getSymbolAddress may have caused additional modules to
782 // be loaded, which may have added new entries to the
783 // ExternalSymbolRelocations map. Consquently, we need to update our
784 // iterator. This is also why retrieval of the relocation list
785 // associated with this symbol is deferred until below this point.
786 // New entries may have been added to the relocation list.
787 i = ExternalSymbolRelocations.find(Name);
789 // We found the symbol in our global table. It was probably in a
790 // Module that we loaded previously.
791 const auto &SymInfo = Loc->second;
792 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
796 // FIXME: Implement error handling that doesn't kill the host program!
798 report_fatal_error("Program used external function '" + Name +
799 "' which could not be resolved!");
801 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
802 // manually and we shouldn't resolve its relocations.
803 if (Addr != UINT64_MAX) {
804 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
805 << format("0x%lx", Addr) << "\n");
806 // This list may have been updated when we called getSymbolAddress, so
807 // don't change this code to get the list earlier.
808 RelocationList &Relocs = i->second;
809 resolveRelocationList(Relocs, Addr);
813 ExternalSymbolRelocations.erase(i);
817 //===----------------------------------------------------------------------===//
818 // RuntimeDyld class implementation
820 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
821 StringRef SectionName) const {
822 for (unsigned I = BeginIdx; I != EndIdx; ++I)
823 if (RTDyld.Sections[I].Name == SectionName)
824 return RTDyld.Sections[I].LoadAddress;
829 void RuntimeDyld::MemoryManager::anchor() {}
830 void RuntimeDyld::SymbolResolver::anchor() {}
832 RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
833 RuntimeDyld::SymbolResolver &Resolver)
834 : MemMgr(MemMgr), Resolver(Resolver) {
835 // FIXME: There's a potential issue lurking here if a single instance of
836 // RuntimeDyld is used to load multiple objects. The current implementation
837 // associates a single memory manager with a RuntimeDyld instance. Even
838 // though the public class spawns a new 'impl' instance for each load,
839 // they share a single memory manager. This can become a problem when page
840 // permissions are applied.
842 ProcessAllSections = false;
846 RuntimeDyld::~RuntimeDyld() {}
848 static std::unique_ptr<RuntimeDyldCOFF>
849 createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
850 RuntimeDyld::SymbolResolver &Resolver,
851 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
852 std::unique_ptr<RuntimeDyldCOFF> Dyld =
853 RuntimeDyldCOFF::create(Arch, MM, Resolver);
854 Dyld->setProcessAllSections(ProcessAllSections);
855 Dyld->setRuntimeDyldChecker(Checker);
859 static std::unique_ptr<RuntimeDyldELF>
860 createRuntimeDyldELF(RuntimeDyld::MemoryManager &MM,
861 RuntimeDyld::SymbolResolver &Resolver,
862 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
863 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver));
864 Dyld->setProcessAllSections(ProcessAllSections);
865 Dyld->setRuntimeDyldChecker(Checker);
869 static std::unique_ptr<RuntimeDyldMachO>
870 createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
871 RuntimeDyld::SymbolResolver &Resolver,
872 bool ProcessAllSections,
873 RuntimeDyldCheckerImpl *Checker) {
874 std::unique_ptr<RuntimeDyldMachO> Dyld =
875 RuntimeDyldMachO::create(Arch, MM, Resolver);
876 Dyld->setProcessAllSections(ProcessAllSections);
877 Dyld->setRuntimeDyldChecker(Checker);
881 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
882 RuntimeDyld::loadObject(const ObjectFile &Obj) {
885 Dyld = createRuntimeDyldELF(MemMgr, Resolver, ProcessAllSections, Checker);
886 else if (Obj.isMachO())
887 Dyld = createRuntimeDyldMachO(
888 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
889 ProcessAllSections, Checker);
890 else if (Obj.isCOFF())
891 Dyld = createRuntimeDyldCOFF(
892 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
893 ProcessAllSections, Checker);
895 report_fatal_error("Incompatible object format!");
898 if (!Dyld->isCompatibleFile(Obj))
899 report_fatal_error("Incompatible object format!");
901 return Dyld->loadObject(Obj);
904 void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
907 return Dyld->getSymbolLocalAddress(Name);
910 RuntimeDyld::SymbolInfo RuntimeDyld::getSymbol(StringRef Name) const {
913 return Dyld->getSymbol(Name);
916 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
918 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
919 Dyld->reassignSectionAddress(SectionID, Addr);
922 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
923 uint64_t TargetAddress) {
924 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
927 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
929 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
931 void RuntimeDyld::registerEHFrames() {
933 Dyld->registerEHFrames();
936 void RuntimeDyld::deregisterEHFrames() {
938 Dyld->deregisterEHFrames();
941 } // end namespace llvm