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 RuntimeDyldImpl::ObjSectionToIDMap
126 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
127 MutexGuard locked(lock);
129 // Save information about our target
130 Arch = (Triple::ArchType)Obj.getArch();
131 IsTargetLittleEndian = Obj.isLittleEndian();
134 // Compute the memory size required to load all sections to be loaded
135 // and pass this information to the memory manager
136 if (MemMgr.needsToReserveAllocationSpace()) {
137 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
138 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
139 MemMgr.reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
142 // Used sections from the object file
143 ObjSectionToIDMap LocalSections;
145 // Common symbols requiring allocation, with their sizes and alignments
146 CommonSymbolList CommonSymbols;
149 DEBUG(dbgs() << "Parse symbols:\n");
150 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
152 uint32_t Flags = I->getFlags();
154 bool IsCommon = Flags & SymbolRef::SF_Common;
156 CommonSymbols.push_back(*I);
158 object::SymbolRef::Type SymType = I->getType();
160 if (SymType == object::SymbolRef::ST_Function ||
161 SymType == object::SymbolRef::ST_Data ||
162 SymType == object::SymbolRef::ST_Unknown) {
164 ErrorOr<StringRef> NameOrErr = I->getName();
165 Check(NameOrErr.getError());
166 StringRef Name = *NameOrErr;
167 ErrorOr<section_iterator> SIOrErr = I->getSection();
168 Check(SIOrErr.getError());
169 section_iterator SI = *SIOrErr;
170 if (SI == Obj.section_end())
173 Check(getOffset(*I, *SI, SectOffset));
174 StringRef SectionData;
175 Check(SI->getContents(SectionData));
176 bool IsCode = SI->isText();
178 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
179 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
180 << " SID: " << SectionID << " Offset: "
181 << format("%p", (uintptr_t)SectOffset)
182 << " flags: " << Flags << "\n");
183 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
184 if (Flags & SymbolRef::SF_Weak)
185 RTDyldSymFlags |= JITSymbolFlags::Weak;
186 if (Flags & SymbolRef::SF_Exported)
187 RTDyldSymFlags |= JITSymbolFlags::Exported;
188 GlobalSymbolTable[Name] =
189 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
194 // Allocate common symbols
195 emitCommonSymbols(Obj, CommonSymbols);
197 // Parse and process relocations
198 DEBUG(dbgs() << "Parse relocations:\n");
199 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
201 unsigned SectionID = 0;
203 section_iterator RelocatedSection = SI->getRelocatedSection();
205 if (RelocatedSection == SE)
208 relocation_iterator I = SI->relocation_begin();
209 relocation_iterator E = SI->relocation_end();
211 if (I == E && !ProcessAllSections)
214 bool IsCode = RelocatedSection->isText();
216 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
217 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
220 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
222 // If there is an attached checker, notify it about the stubs for this
223 // section so that they can be verified.
225 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
228 // Give the subclasses a chance to tie-up any loose ends.
229 finalizeLoad(Obj, LocalSections);
231 // for (auto E : LocalSections)
232 // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
234 return LocalSections;
237 // A helper method for computeTotalAllocSize.
238 // Computes the memory size required to allocate sections with the given sizes,
239 // assuming that all sections are allocated with the given alignment
241 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
242 uint64_t Alignment) {
243 uint64_t TotalSize = 0;
244 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
245 uint64_t AlignedSize =
246 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
247 TotalSize += AlignedSize;
252 static bool isRequiredForExecution(const SectionRef Section) {
253 const ObjectFile *Obj = Section.getObject();
254 if (isa<object::ELFObjectFileBase>(Obj))
255 return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
256 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
257 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
258 // Avoid loading zero-sized COFF sections.
259 // In PE files, VirtualSize gives the section size, and SizeOfRawData
260 // may be zero for sections with content. In Obj files, SizeOfRawData
261 // gives the section size, and VirtualSize is always zero. Hence
262 // the need to check for both cases below.
263 bool HasContent = (CoffSection->VirtualSize > 0)
264 || (CoffSection->SizeOfRawData > 0);
265 bool IsDiscardable = CoffSection->Characteristics &
266 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
267 return HasContent && !IsDiscardable;
270 assert(isa<MachOObjectFile>(Obj));
274 static bool isReadOnlyData(const SectionRef Section) {
275 const ObjectFile *Obj = Section.getObject();
276 if (isa<object::ELFObjectFileBase>(Obj))
277 return !(ELFSectionRef(Section).getFlags() &
278 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
279 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
280 return ((COFFObj->getCOFFSection(Section)->Characteristics &
281 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
282 | COFF::IMAGE_SCN_MEM_READ
283 | COFF::IMAGE_SCN_MEM_WRITE))
285 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
286 | COFF::IMAGE_SCN_MEM_READ));
288 assert(isa<MachOObjectFile>(Obj));
292 static bool isZeroInit(const SectionRef Section) {
293 const ObjectFile *Obj = Section.getObject();
294 if (isa<object::ELFObjectFileBase>(Obj))
295 return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
296 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
297 return COFFObj->getCOFFSection(Section)->Characteristics &
298 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
300 auto *MachO = cast<MachOObjectFile>(Obj);
301 unsigned SectionType = MachO->getSectionType(Section);
302 return SectionType == MachO::S_ZEROFILL ||
303 SectionType == MachO::S_GB_ZEROFILL;
306 // Compute an upper bound of the memory size that is required to load all
308 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
310 uint64_t &DataSizeRO,
311 uint64_t &DataSizeRW) {
312 // Compute the size of all sections required for execution
313 std::vector<uint64_t> CodeSectionSizes;
314 std::vector<uint64_t> ROSectionSizes;
315 std::vector<uint64_t> RWSectionSizes;
316 uint64_t MaxAlignment = sizeof(void *);
318 // Collect sizes of all sections to be loaded;
319 // also determine the max alignment of all sections
320 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
322 const SectionRef &Section = *SI;
324 bool IsRequired = isRequiredForExecution(Section);
326 // Consider only the sections that are required to be loaded for execution
329 uint64_t DataSize = Section.getSize();
330 uint64_t Alignment64 = Section.getAlignment();
331 bool IsCode = Section.isText();
332 bool IsReadOnly = isReadOnlyData(Section);
333 Check(Section.getName(Name));
334 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
336 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
337 uint64_t SectionSize = DataSize + StubBufSize;
339 // The .eh_frame section (at least on Linux) needs an extra four bytes
341 // with zeroes added at the end. For MachO objects, this section has a
342 // slightly different name, so this won't have any effect for MachO
344 if (Name == ".eh_frame")
351 CodeSectionSizes.push_back(SectionSize);
352 } else if (IsReadOnly) {
353 ROSectionSizes.push_back(SectionSize);
355 RWSectionSizes.push_back(SectionSize);
358 // update the max alignment
359 if (Alignment > MaxAlignment) {
360 MaxAlignment = Alignment;
365 // Compute the size of all common symbols
366 uint64_t CommonSize = 0;
367 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
369 uint32_t Flags = I->getFlags();
370 if (Flags & SymbolRef::SF_Common) {
371 // Add the common symbols to a list. We'll allocate them all below.
372 uint64_t Size = I->getCommonSize();
376 if (CommonSize != 0) {
377 RWSectionSizes.push_back(CommonSize);
380 // Compute the required allocation space for each different type of sections
381 // (code, read-only data, read-write data) assuming that all sections are
382 // allocated with the max alignment. Note that we cannot compute with the
383 // individual alignments of the sections, because then the required size
384 // depends on the order, in which the sections are allocated.
385 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
386 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
387 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
390 // compute stub buffer size for the given section
391 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
392 const SectionRef &Section) {
393 unsigned StubSize = getMaxStubSize();
397 // FIXME: this is an inefficient way to handle this. We should computed the
398 // necessary section allocation size in loadObject by walking all the sections
400 unsigned StubBufSize = 0;
401 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
403 section_iterator RelSecI = SI->getRelocatedSection();
404 if (!(RelSecI == Section))
407 for (const RelocationRef &Reloc : SI->relocations()) {
409 StubBufSize += StubSize;
413 // Get section data size and alignment
414 uint64_t DataSize = Section.getSize();
415 uint64_t Alignment64 = Section.getAlignment();
417 // Add stubbuf size alignment
418 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
419 unsigned StubAlignment = getStubAlignment();
420 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
421 if (StubAlignment > EndAlignment)
422 StubBufSize += StubAlignment - EndAlignment;
426 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
427 unsigned Size) const {
429 if (IsTargetLittleEndian) {
432 Result = (Result << 8) | *Src--;
435 Result = (Result << 8) | *Src++;
440 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
441 unsigned Size) const {
442 if (IsTargetLittleEndian) {
444 *Dst++ = Value & 0xFF;
450 *Dst-- = Value & 0xFF;
456 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
457 CommonSymbolList &CommonSymbols) {
458 if (CommonSymbols.empty())
461 uint64_t CommonSize = 0;
462 CommonSymbolList SymbolsToAllocate;
464 DEBUG(dbgs() << "Processing common symbols...\n");
466 for (const auto &Sym : CommonSymbols) {
467 ErrorOr<StringRef> NameOrErr = Sym.getName();
468 Check(NameOrErr.getError());
469 StringRef Name = *NameOrErr;
471 // Skip common symbols already elsewhere.
472 if (GlobalSymbolTable.count(Name) ||
473 Resolver.findSymbolInLogicalDylib(Name)) {
474 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
479 uint32_t Align = Sym.getAlignment();
480 uint64_t Size = Sym.getCommonSize();
482 CommonSize += Align + Size;
483 SymbolsToAllocate.push_back(Sym);
486 // Allocate memory for the section
487 unsigned SectionID = Sections.size();
488 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
489 SectionID, StringRef(), false);
491 report_fatal_error("Unable to allocate memory for common symbols!");
493 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
494 memset(Addr, 0, CommonSize);
496 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
497 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
499 // Assign the address of each symbol
500 for (auto &Sym : SymbolsToAllocate) {
501 uint32_t Align = Sym.getAlignment();
502 uint64_t Size = Sym.getCommonSize();
503 ErrorOr<StringRef> NameOrErr = Sym.getName();
504 Check(NameOrErr.getError());
505 StringRef Name = *NameOrErr;
507 // This symbol has an alignment requirement.
508 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
510 Offset += AlignOffset;
512 uint32_t Flags = Sym.getFlags();
513 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
514 if (Flags & SymbolRef::SF_Weak)
515 RTDyldSymFlags |= JITSymbolFlags::Weak;
516 if (Flags & SymbolRef::SF_Exported)
517 RTDyldSymFlags |= JITSymbolFlags::Exported;
518 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
519 << format("%p", Addr) << "\n");
520 GlobalSymbolTable[Name] =
521 SymbolTableEntry(SectionID, Offset, RTDyldSymFlags);
527 Checker->registerSection(Obj.getFileName(), SectionID);
530 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
531 const SectionRef &Section, bool IsCode) {
534 uint64_t Alignment64 = Section.getAlignment();
536 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
537 unsigned PaddingSize = 0;
538 unsigned StubBufSize = 0;
540 bool IsRequired = isRequiredForExecution(Section);
541 bool IsVirtual = Section.isVirtual();
542 bool IsZeroInit = isZeroInit(Section);
543 bool IsReadOnly = isReadOnlyData(Section);
544 uint64_t DataSize = Section.getSize();
545 Check(Section.getName(Name));
547 StubBufSize = computeSectionStubBufSize(Obj, Section);
549 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
550 // with zeroes added at the end. For MachO objects, this section has a
551 // slightly different name, so this won't have any effect for MachO objects.
552 if (Name == ".eh_frame")
556 unsigned SectionID = Sections.size();
558 const char *pData = nullptr;
560 // In either case, set the location of the unrelocated section in memory,
561 // since we still process relocations for it even if we're not applying them.
562 Check(Section.getContents(data));
563 // Virtual sections have no data in the object image, so leave pData = 0
567 // Some sections, such as debug info, don't need to be loaded for execution.
568 // Leave those where they are.
570 Allocate = DataSize + PaddingSize + StubBufSize;
573 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
575 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
578 report_fatal_error("Unable to allocate section memory!");
580 // Zero-initialize or copy the data from the image
581 if (IsZeroInit || IsVirtual)
582 memset(Addr, 0, DataSize);
584 memcpy(Addr, pData, DataSize);
586 // Fill in any extra bytes we allocated for padding
587 if (PaddingSize != 0) {
588 memset(Addr + DataSize, 0, PaddingSize);
589 // Update the DataSize variable so that the stub offset is set correctly.
590 DataSize += PaddingSize;
593 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
594 << " obj addr: " << format("%p", pData)
595 << " new addr: " << format("%p", Addr)
596 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
597 << " Allocate: " << Allocate << "\n");
599 // Even if we didn't load the section, we need to record an entry for it
600 // to handle later processing (and by 'handle' I mean don't do anything
601 // with these sections).
604 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
605 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
606 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
607 << " Allocate: " << Allocate << "\n");
610 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
613 Checker->registerSection(Obj.getFileName(), SectionID);
618 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
619 const SectionRef &Section,
621 ObjSectionToIDMap &LocalSections) {
623 unsigned SectionID = 0;
624 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
625 if (i != LocalSections.end())
626 SectionID = i->second;
628 SectionID = emitSection(Obj, Section, IsCode);
629 LocalSections[Section] = SectionID;
634 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
635 unsigned SectionID) {
636 Relocations[SectionID].push_back(RE);
639 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
640 StringRef SymbolName) {
641 // Relocation by symbol. If the symbol is found in the global symbol table,
642 // create an appropriate section relocation. Otherwise, add it to
643 // ExternalSymbolRelocations.
644 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
645 if (Loc == GlobalSymbolTable.end()) {
646 ExternalSymbolRelocations[SymbolName].push_back(RE);
648 // Copy the RE since we want to modify its addend.
649 RelocationEntry RECopy = RE;
650 const auto &SymInfo = Loc->second;
651 RECopy.Addend += SymInfo.getOffset();
652 Relocations[SymInfo.getSectionID()].push_back(RECopy);
656 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
657 unsigned AbiVariant) {
658 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
659 // This stub has to be able to access the full address space,
660 // since symbol lookup won't necessarily find a handy, in-range,
661 // PLT stub for functions which could be anywhere.
662 // Stub can use ip0 (== x16) to calculate address
663 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
664 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
665 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
666 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
667 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
670 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
671 // TODO: There is only ARM far stub now. We should add the Thumb stub,
672 // and stubs for branches Thumb - ARM and ARM - Thumb.
673 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
675 } else if (IsMipsO32ABI) {
676 // 0: 3c190000 lui t9,%hi(addr).
677 // 4: 27390000 addiu t9,t9,%lo(addr).
678 // 8: 03200008 jr t9.
680 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
681 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
683 writeBytesUnaligned(LuiT9Instr, Addr, 4);
684 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
685 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
686 writeBytesUnaligned(NopInstr, Addr+12, 4);
688 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
689 // Depending on which version of the ELF ABI is in use, we need to
690 // generate one of two variants of the stub. They both start with
691 // the same sequence to load the target address into r12.
692 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
693 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
694 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
695 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
696 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
697 if (AbiVariant == 2) {
698 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
699 // The address is already in r12 as required by the ABI. Branch to it.
700 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
701 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
702 writeInt32BE(Addr+28, 0x4E800420); // bctr
704 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
705 // Load the function address on r11 and sets it to control register. Also
706 // loads the function TOC in r2 and environment pointer to r11.
707 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
708 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
709 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
710 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
711 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
712 writeInt32BE(Addr+40, 0x4E800420); // bctr
715 } else if (Arch == Triple::systemz) {
716 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
717 writeInt16BE(Addr+2, 0x0000);
718 writeInt16BE(Addr+4, 0x0004);
719 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
720 // 8-byte address stored at Addr + 8
722 } else if (Arch == Triple::x86_64) {
724 *(Addr+1) = 0x25; // rip
725 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
726 } else if (Arch == Triple::x86) {
727 *Addr = 0xE9; // 32-bit pc-relative jump.
732 // Assign an address to a symbol name and resolve all the relocations
733 // associated with it.
734 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
736 // The address to use for relocation resolution is not
737 // the address of the local section buffer. We must be doing
738 // a remote execution environment of some sort. Relocations can't
739 // be applied until all the sections have been moved. The client must
740 // trigger this with a call to MCJIT::finalize() or
741 // RuntimeDyld::resolveRelocations().
743 // Addr is a uint64_t because we can't assume the pointer width
744 // of the target is the same as that of the host. Just use a generic
745 // "big enough" type.
746 DEBUG(dbgs() << "Reassigning address for section "
747 << SectionID << " (" << Sections[SectionID].Name << "): "
748 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
749 << format("0x%016" PRIx64, Addr) << "\n");
750 Sections[SectionID].LoadAddress = Addr;
753 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
755 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
756 const RelocationEntry &RE = Relocs[i];
757 // Ignore relocations for sections that were not loaded
758 if (Sections[RE.SectionID].Address == nullptr)
760 resolveRelocation(RE, Value);
764 void RuntimeDyldImpl::resolveExternalSymbols() {
765 while (!ExternalSymbolRelocations.empty()) {
766 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
768 StringRef Name = i->first();
769 if (Name.size() == 0) {
770 // This is an absolute symbol, use an address of zero.
771 DEBUG(dbgs() << "Resolving absolute relocations."
773 RelocationList &Relocs = i->second;
774 resolveRelocationList(Relocs, 0);
777 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
778 if (Loc == GlobalSymbolTable.end()) {
779 // This is an external symbol, try to get its address from the symbol
781 Addr = Resolver.findSymbol(Name.data()).getAddress();
782 // The call to getSymbolAddress may have caused additional modules to
783 // be loaded, which may have added new entries to the
784 // ExternalSymbolRelocations map. Consquently, we need to update our
785 // iterator. This is also why retrieval of the relocation list
786 // associated with this symbol is deferred until below this point.
787 // New entries may have been added to the relocation list.
788 i = ExternalSymbolRelocations.find(Name);
790 // We found the symbol in our global table. It was probably in a
791 // Module that we loaded previously.
792 const auto &SymInfo = Loc->second;
793 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
797 // FIXME: Implement error handling that doesn't kill the host program!
799 report_fatal_error("Program used external function '" + Name +
800 "' which could not be resolved!");
802 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
803 // manually and we shouldn't resolve its relocations.
804 if (Addr != UINT64_MAX) {
805 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
806 << format("0x%lx", Addr) << "\n");
807 // This list may have been updated when we called getSymbolAddress, so
808 // don't change this code to get the list earlier.
809 RelocationList &Relocs = i->second;
810 resolveRelocationList(Relocs, Addr);
814 ExternalSymbolRelocations.erase(i);
818 //===----------------------------------------------------------------------===//
819 // RuntimeDyld class implementation
821 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
822 const object::SectionRef &Sec) const {
824 // llvm::dbgs() << "Searching for " << Sec.getRawDataRefImpl() << " in:\n";
825 // for (auto E : ObjSecToIDMap)
826 // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
828 auto I = ObjSecToIDMap.find(Sec);
829 if (I != ObjSecToIDMap.end()) {
830 // llvm::dbgs() << "Found ID " << I->second << " for Sec: " << Sec.getRawDataRefImpl() << ", LoadAddress = " << RTDyld.Sections[I->second].LoadAddress << "\n";
831 return RTDyld.Sections[I->second].LoadAddress;
833 // llvm::dbgs() << "Not found.\n";
839 void RuntimeDyld::MemoryManager::anchor() {}
840 void RuntimeDyld::SymbolResolver::anchor() {}
842 RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
843 RuntimeDyld::SymbolResolver &Resolver)
844 : MemMgr(MemMgr), Resolver(Resolver) {
845 // FIXME: There's a potential issue lurking here if a single instance of
846 // RuntimeDyld is used to load multiple objects. The current implementation
847 // associates a single memory manager with a RuntimeDyld instance. Even
848 // though the public class spawns a new 'impl' instance for each load,
849 // they share a single memory manager. This can become a problem when page
850 // permissions are applied.
852 ProcessAllSections = false;
856 RuntimeDyld::~RuntimeDyld() {}
858 static std::unique_ptr<RuntimeDyldCOFF>
859 createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
860 RuntimeDyld::SymbolResolver &Resolver,
861 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
862 std::unique_ptr<RuntimeDyldCOFF> Dyld =
863 RuntimeDyldCOFF::create(Arch, MM, Resolver);
864 Dyld->setProcessAllSections(ProcessAllSections);
865 Dyld->setRuntimeDyldChecker(Checker);
869 static std::unique_ptr<RuntimeDyldELF>
870 createRuntimeDyldELF(RuntimeDyld::MemoryManager &MM,
871 RuntimeDyld::SymbolResolver &Resolver,
872 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
873 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver));
874 Dyld->setProcessAllSections(ProcessAllSections);
875 Dyld->setRuntimeDyldChecker(Checker);
879 static std::unique_ptr<RuntimeDyldMachO>
880 createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
881 RuntimeDyld::SymbolResolver &Resolver,
882 bool ProcessAllSections,
883 RuntimeDyldCheckerImpl *Checker) {
884 std::unique_ptr<RuntimeDyldMachO> Dyld =
885 RuntimeDyldMachO::create(Arch, MM, Resolver);
886 Dyld->setProcessAllSections(ProcessAllSections);
887 Dyld->setRuntimeDyldChecker(Checker);
891 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
892 RuntimeDyld::loadObject(const ObjectFile &Obj) {
895 Dyld = createRuntimeDyldELF(MemMgr, Resolver, ProcessAllSections, Checker);
896 else if (Obj.isMachO())
897 Dyld = createRuntimeDyldMachO(
898 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
899 ProcessAllSections, Checker);
900 else if (Obj.isCOFF())
901 Dyld = createRuntimeDyldCOFF(
902 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
903 ProcessAllSections, Checker);
905 report_fatal_error("Incompatible object format!");
908 if (!Dyld->isCompatibleFile(Obj))
909 report_fatal_error("Incompatible object format!");
911 return Dyld->loadObject(Obj);
914 void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
917 return Dyld->getSymbolLocalAddress(Name);
920 RuntimeDyld::SymbolInfo RuntimeDyld::getSymbol(StringRef Name) const {
923 return Dyld->getSymbol(Name);
926 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
928 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
929 Dyld->reassignSectionAddress(SectionID, Addr);
932 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
933 uint64_t TargetAddress) {
934 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
937 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
939 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
941 void RuntimeDyld::registerEHFrames() {
943 Dyld->registerEHFrames();
946 void RuntimeDyld::deregisterEHFrames() {
948 Dyld->deregisterEHFrames();
951 } // end namespace llvm