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, uint64_t &Result) {
118 if (std::error_code EC = Sym.getAddress(Address))
121 if (Address == UnknownAddressOrSize) {
122 Result = UnknownAddressOrSize;
123 return object_error::success;
126 const ObjectFile *Obj = Sym.getObject();
127 section_iterator SecI(Obj->section_begin());
128 if (std::error_code EC = Sym.getSection(SecI))
131 if (SecI == Obj->section_end()) {
132 Result = UnknownAddressOrSize;
133 return object_error::success;
136 uint64_t SectionAddress = SecI->getAddress();
137 Result = Address - SectionAddress;
138 return object_error::success;
141 std::pair<unsigned, unsigned>
142 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
143 MutexGuard locked(lock);
145 // Grab the first Section ID. We'll use this later to construct the underlying
146 // range for the returned LoadedObjectInfo.
147 unsigned SectionsAddedBeginIdx = Sections.size();
149 // Save information about our target
150 Arch = (Triple::ArchType)Obj.getArch();
151 IsTargetLittleEndian = Obj.isLittleEndian();
153 // Compute the memory size required to load all sections to be loaded
154 // and pass this information to the memory manager
155 if (MemMgr.needsToReserveAllocationSpace()) {
156 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
157 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
158 MemMgr.reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
161 // Used sections from the object file
162 ObjSectionToIDMap LocalSections;
164 // Common symbols requiring allocation, with their sizes and alignments
165 CommonSymbolList CommonSymbols;
168 DEBUG(dbgs() << "Parse symbols:\n");
169 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
171 uint32_t Flags = I->getFlags();
173 bool IsCommon = Flags & SymbolRef::SF_Common;
175 CommonSymbols.push_back(*I);
177 object::SymbolRef::Type SymType;
178 Check(I->getType(SymType));
180 if (SymType == object::SymbolRef::ST_Function ||
181 SymType == object::SymbolRef::ST_Data ||
182 SymType == object::SymbolRef::ST_Unknown) {
186 Check(I->getName(Name));
187 Check(getOffset(*I, SectOffset));
188 section_iterator SI = Obj.section_end();
189 Check(I->getSection(SI));
190 if (SI == Obj.section_end())
192 StringRef SectionData;
193 Check(SI->getContents(SectionData));
194 bool IsCode = SI->isText();
196 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
197 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
198 << " SID: " << SectionID << " Offset: "
199 << format("%p", (uintptr_t)SectOffset)
200 << " flags: " << Flags << "\n");
201 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
202 if (Flags & SymbolRef::SF_Weak)
203 RTDyldSymFlags |= JITSymbolFlags::Weak;
204 if (Flags & SymbolRef::SF_Exported)
205 RTDyldSymFlags |= JITSymbolFlags::Exported;
206 GlobalSymbolTable[Name] =
207 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
212 // Allocate common symbols
213 emitCommonSymbols(Obj, CommonSymbols);
215 // Parse and process relocations
216 DEBUG(dbgs() << "Parse relocations:\n");
217 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
219 unsigned SectionID = 0;
221 section_iterator RelocatedSection = SI->getRelocatedSection();
223 if (RelocatedSection == SE)
226 relocation_iterator I = SI->relocation_begin();
227 relocation_iterator E = SI->relocation_end();
229 if (I == E && !ProcessAllSections)
232 bool IsCode = RelocatedSection->isText();
234 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
235 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
238 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
240 // If there is an attached checker, notify it about the stubs for this
241 // section so that they can be verified.
243 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
246 // Give the subclasses a chance to tie-up any loose ends.
247 finalizeLoad(Obj, LocalSections);
249 unsigned SectionsAddedEndIdx = Sections.size();
251 return std::make_pair(SectionsAddedBeginIdx, SectionsAddedEndIdx);
254 // A helper method for computeTotalAllocSize.
255 // Computes the memory size required to allocate sections with the given sizes,
256 // assuming that all sections are allocated with the given alignment
258 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
259 uint64_t Alignment) {
260 uint64_t TotalSize = 0;
261 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
262 uint64_t AlignedSize =
263 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
264 TotalSize += AlignedSize;
269 static bool isRequiredForExecution(const SectionRef &Section) {
270 const ObjectFile *Obj = Section.getObject();
271 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
272 return ELFObj->getSectionFlags(Section) & ELF::SHF_ALLOC;
273 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
274 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
275 // Avoid loading zero-sized COFF sections.
276 // In PE files, VirtualSize gives the section size, and SizeOfRawData
277 // may be zero for sections with content. In Obj files, SizeOfRawData
278 // gives the section size, and VirtualSize is always zero. Hence
279 // the need to check for both cases below.
280 bool HasContent = (CoffSection->VirtualSize > 0)
281 || (CoffSection->SizeOfRawData > 0);
282 bool IsDiscardable = CoffSection->Characteristics &
283 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
284 return HasContent && !IsDiscardable;
287 assert(isa<MachOObjectFile>(Obj));
291 static bool isReadOnlyData(const SectionRef &Section) {
292 const ObjectFile *Obj = Section.getObject();
293 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
294 return !(ELFObj->getSectionFlags(Section) &
295 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
296 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
297 return ((COFFObj->getCOFFSection(Section)->Characteristics &
298 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
299 | COFF::IMAGE_SCN_MEM_READ
300 | COFF::IMAGE_SCN_MEM_WRITE))
302 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
303 | COFF::IMAGE_SCN_MEM_READ));
305 assert(isa<MachOObjectFile>(Obj));
309 static bool isZeroInit(const SectionRef &Section) {
310 const ObjectFile *Obj = Section.getObject();
311 if (auto *ELFObj = dyn_cast<object::ELFObjectFileBase>(Obj))
312 return ELFObj->getSectionType(Section) == ELF::SHT_NOBITS;
313 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
314 return COFFObj->getCOFFSection(Section)->Characteristics &
315 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
317 auto *MachO = cast<MachOObjectFile>(Obj);
318 unsigned SectionType = MachO->getSectionType(Section);
319 return SectionType == MachO::S_ZEROFILL ||
320 SectionType == MachO::S_GB_ZEROFILL;
323 // Compute an upper bound of the memory size that is required to load all
325 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
327 uint64_t &DataSizeRO,
328 uint64_t &DataSizeRW) {
329 // Compute the size of all sections required for execution
330 std::vector<uint64_t> CodeSectionSizes;
331 std::vector<uint64_t> ROSectionSizes;
332 std::vector<uint64_t> RWSectionSizes;
333 uint64_t MaxAlignment = sizeof(void *);
335 // Collect sizes of all sections to be loaded;
336 // also determine the max alignment of all sections
337 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
339 const SectionRef &Section = *SI;
341 bool IsRequired = isRequiredForExecution(Section);
343 // Consider only the sections that are required to be loaded for execution
346 uint64_t DataSize = Section.getSize();
347 uint64_t Alignment64 = Section.getAlignment();
348 bool IsCode = Section.isText();
349 bool IsReadOnly = isReadOnlyData(Section);
350 Check(Section.getName(Name));
351 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
353 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
354 uint64_t SectionSize = DataSize + StubBufSize;
356 // The .eh_frame section (at least on Linux) needs an extra four bytes
358 // with zeroes added at the end. For MachO objects, this section has a
359 // slightly different name, so this won't have any effect for MachO
361 if (Name == ".eh_frame")
368 CodeSectionSizes.push_back(SectionSize);
369 } else if (IsReadOnly) {
370 ROSectionSizes.push_back(SectionSize);
372 RWSectionSizes.push_back(SectionSize);
375 // update the max alignment
376 if (Alignment > MaxAlignment) {
377 MaxAlignment = Alignment;
382 // Compute the size of all common symbols
383 uint64_t CommonSize = 0;
384 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
386 uint32_t Flags = I->getFlags();
387 if (Flags & SymbolRef::SF_Common) {
388 // Add the common symbols to a list. We'll allocate them all below.
390 Check(I->getSize(Size));
394 if (CommonSize != 0) {
395 RWSectionSizes.push_back(CommonSize);
398 // Compute the required allocation space for each different type of sections
399 // (code, read-only data, read-write data) assuming that all sections are
400 // allocated with the max alignment. Note that we cannot compute with the
401 // individual alignments of the sections, because then the required size
402 // depends on the order, in which the sections are allocated.
403 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
404 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
405 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
408 // compute stub buffer size for the given section
409 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
410 const SectionRef &Section) {
411 unsigned StubSize = getMaxStubSize();
415 // FIXME: this is an inefficient way to handle this. We should computed the
416 // necessary section allocation size in loadObject by walking all the sections
418 unsigned StubBufSize = 0;
419 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
421 section_iterator RelSecI = SI->getRelocatedSection();
422 if (!(RelSecI == Section))
425 for (const RelocationRef &Reloc : SI->relocations()) {
427 StubBufSize += StubSize;
431 // Get section data size and alignment
432 uint64_t DataSize = Section.getSize();
433 uint64_t Alignment64 = Section.getAlignment();
435 // Add stubbuf size alignment
436 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
437 unsigned StubAlignment = getStubAlignment();
438 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
439 if (StubAlignment > EndAlignment)
440 StubBufSize += StubAlignment - EndAlignment;
444 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
445 unsigned Size) const {
447 if (IsTargetLittleEndian) {
450 Result = (Result << 8) | *Src--;
453 Result = (Result << 8) | *Src++;
458 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
459 unsigned Size) const {
460 if (IsTargetLittleEndian) {
462 *Dst++ = Value & 0xFF;
468 *Dst-- = Value & 0xFF;
474 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
475 CommonSymbolList &CommonSymbols) {
476 if (CommonSymbols.empty())
479 uint64_t CommonSize = 0;
480 CommonSymbolList SymbolsToAllocate;
482 DEBUG(dbgs() << "Processing common symbols...\n");
484 for (const auto &Sym : CommonSymbols) {
486 Check(Sym.getName(Name));
488 // Skip common symbols already elsewhere.
489 if (GlobalSymbolTable.count(Name) ||
490 Resolver.findSymbolInLogicalDylib(Name)) {
491 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
498 Check(Sym.getAlignment(Align));
499 Check(Sym.getSize(Size));
501 CommonSize += Align + Size;
502 SymbolsToAllocate.push_back(Sym);
505 // Allocate memory for the section
506 unsigned SectionID = Sections.size();
507 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
508 SectionID, StringRef(), false);
510 report_fatal_error("Unable to allocate memory for common symbols!");
512 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
513 memset(Addr, 0, CommonSize);
515 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
516 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
518 // Assign the address of each symbol
519 for (auto &Sym : SymbolsToAllocate) {
523 Check(Sym.getAlignment(Align));
524 Check(Sym.getSize(Size));
525 Check(Sym.getName(Name));
527 // This symbol has an alignment requirement.
528 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
530 Offset += AlignOffset;
532 uint32_t Flags = Sym.getFlags();
533 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
534 if (Flags & SymbolRef::SF_Weak)
535 RTDyldSymFlags |= JITSymbolFlags::Weak;
536 if (Flags & SymbolRef::SF_Exported)
537 RTDyldSymFlags |= JITSymbolFlags::Exported;
538 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
539 << format("%p", Addr) << "\n");
540 GlobalSymbolTable[Name] =
541 SymbolTableEntry(SectionID, Offset, RTDyldSymFlags);
547 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
548 const SectionRef &Section, bool IsCode) {
551 uint64_t Alignment64 = Section.getAlignment();
553 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
554 unsigned PaddingSize = 0;
555 unsigned StubBufSize = 0;
557 bool IsRequired = isRequiredForExecution(Section);
558 bool IsVirtual = Section.isVirtual();
559 bool IsZeroInit = isZeroInit(Section);
560 bool IsReadOnly = isReadOnlyData(Section);
561 uint64_t DataSize = Section.getSize();
562 Check(Section.getName(Name));
564 StubBufSize = computeSectionStubBufSize(Obj, Section);
566 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
567 // with zeroes added at the end. For MachO objects, this section has a
568 // slightly different name, so this won't have any effect for MachO objects.
569 if (Name == ".eh_frame")
573 unsigned SectionID = Sections.size();
575 const char *pData = nullptr;
577 // Some sections, such as debug info, don't need to be loaded for execution.
578 // Leave those where they are.
580 Check(Section.getContents(data));
581 Allocate = DataSize + PaddingSize + StubBufSize;
584 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
586 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
589 report_fatal_error("Unable to allocate section memory!");
591 // Virtual sections have no data in the object image, so leave pData = 0
595 // Zero-initialize or copy the data from the image
596 if (IsZeroInit || IsVirtual)
597 memset(Addr, 0, DataSize);
599 memcpy(Addr, pData, DataSize);
601 // Fill in any extra bytes we allocated for padding
602 if (PaddingSize != 0) {
603 memset(Addr + DataSize, 0, PaddingSize);
604 // Update the DataSize variable so that the stub offset is set correctly.
605 DataSize += PaddingSize;
608 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
609 << " obj addr: " << format("%p", pData)
610 << " new addr: " << format("%p", Addr)
611 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
612 << " Allocate: " << Allocate << "\n");
614 // Even if we didn't load the section, we need to record an entry for it
615 // to handle later processing (and by 'handle' I mean don't do anything
616 // with these sections).
619 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
620 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
621 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
622 << " Allocate: " << Allocate << "\n");
625 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
628 Checker->registerSection(Obj.getFileName(), SectionID);
633 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
634 const SectionRef &Section,
636 ObjSectionToIDMap &LocalSections) {
638 unsigned SectionID = 0;
639 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
640 if (i != LocalSections.end())
641 SectionID = i->second;
643 SectionID = emitSection(Obj, Section, IsCode);
644 LocalSections[Section] = SectionID;
649 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
650 unsigned SectionID) {
651 Relocations[SectionID].push_back(RE);
654 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
655 StringRef SymbolName) {
656 // Relocation by symbol. If the symbol is found in the global symbol table,
657 // create an appropriate section relocation. Otherwise, add it to
658 // ExternalSymbolRelocations.
659 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
660 if (Loc == GlobalSymbolTable.end()) {
661 ExternalSymbolRelocations[SymbolName].push_back(RE);
663 // Copy the RE since we want to modify its addend.
664 RelocationEntry RECopy = RE;
665 const auto &SymInfo = Loc->second;
666 RECopy.Addend += SymInfo.getOffset();
667 Relocations[SymInfo.getSectionID()].push_back(RECopy);
671 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
672 unsigned AbiVariant) {
673 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
674 // This stub has to be able to access the full address space,
675 // since symbol lookup won't necessarily find a handy, in-range,
676 // PLT stub for functions which could be anywhere.
677 // Stub can use ip0 (== x16) to calculate address
678 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
679 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
680 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
681 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
682 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
685 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
686 // TODO: There is only ARM far stub now. We should add the Thumb stub,
687 // and stubs for branches Thumb - ARM and ARM - Thumb.
688 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
690 } else if (Arch == Triple::mipsel || Arch == Triple::mips) {
691 // 0: 3c190000 lui t9,%hi(addr).
692 // 4: 27390000 addiu t9,t9,%lo(addr).
693 // 8: 03200008 jr t9.
695 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
696 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
698 writeBytesUnaligned(LuiT9Instr, Addr, 4);
699 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
700 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
701 writeBytesUnaligned(NopInstr, Addr+12, 4);
703 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
704 // Depending on which version of the ELF ABI is in use, we need to
705 // generate one of two variants of the stub. They both start with
706 // the same sequence to load the target address into r12.
707 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
708 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
709 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
710 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
711 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
712 if (AbiVariant == 2) {
713 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
714 // The address is already in r12 as required by the ABI. Branch to it.
715 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
716 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
717 writeInt32BE(Addr+28, 0x4E800420); // bctr
719 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
720 // Load the function address on r11 and sets it to control register. Also
721 // loads the function TOC in r2 and environment pointer to r11.
722 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
723 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
724 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
725 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
726 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
727 writeInt32BE(Addr+40, 0x4E800420); // bctr
730 } else if (Arch == Triple::systemz) {
731 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
732 writeInt16BE(Addr+2, 0x0000);
733 writeInt16BE(Addr+4, 0x0004);
734 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
735 // 8-byte address stored at Addr + 8
737 } else if (Arch == Triple::x86_64) {
739 *(Addr+1) = 0x25; // rip
740 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
741 } else if (Arch == Triple::x86) {
742 *Addr = 0xE9; // 32-bit pc-relative jump.
747 // Assign an address to a symbol name and resolve all the relocations
748 // associated with it.
749 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
751 // The address to use for relocation resolution is not
752 // the address of the local section buffer. We must be doing
753 // a remote execution environment of some sort. Relocations can't
754 // be applied until all the sections have been moved. The client must
755 // trigger this with a call to MCJIT::finalize() or
756 // RuntimeDyld::resolveRelocations().
758 // Addr is a uint64_t because we can't assume the pointer width
759 // of the target is the same as that of the host. Just use a generic
760 // "big enough" type.
761 DEBUG(dbgs() << "Reassigning address for section "
762 << SectionID << " (" << Sections[SectionID].Name << "): "
763 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
764 << format("0x%016" PRIx64, Addr) << "\n");
765 Sections[SectionID].LoadAddress = Addr;
768 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
770 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
771 const RelocationEntry &RE = Relocs[i];
772 // Ignore relocations for sections that were not loaded
773 if (Sections[RE.SectionID].Address == nullptr)
775 resolveRelocation(RE, Value);
779 void RuntimeDyldImpl::resolveExternalSymbols() {
780 while (!ExternalSymbolRelocations.empty()) {
781 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
783 StringRef Name = i->first();
784 if (Name.size() == 0) {
785 // This is an absolute symbol, use an address of zero.
786 DEBUG(dbgs() << "Resolving absolute relocations."
788 RelocationList &Relocs = i->second;
789 resolveRelocationList(Relocs, 0);
792 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
793 if (Loc == GlobalSymbolTable.end()) {
794 // This is an external symbol, try to get its address from the symbol
796 Addr = Resolver.findSymbol(Name.data()).getAddress();
797 // The call to getSymbolAddress may have caused additional modules to
798 // be loaded, which may have added new entries to the
799 // ExternalSymbolRelocations map. Consquently, we need to update our
800 // iterator. This is also why retrieval of the relocation list
801 // associated with this symbol is deferred until below this point.
802 // New entries may have been added to the relocation list.
803 i = ExternalSymbolRelocations.find(Name);
805 // We found the symbol in our global table. It was probably in a
806 // Module that we loaded previously.
807 const auto &SymInfo = Loc->second;
808 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
812 // FIXME: Implement error handling that doesn't kill the host program!
814 report_fatal_error("Program used external function '" + Name +
815 "' which could not be resolved!");
817 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
818 << format("0x%lx", Addr) << "\n");
819 // This list may have been updated when we called getSymbolAddress, so
820 // don't change this code to get the list earlier.
821 RelocationList &Relocs = i->second;
822 resolveRelocationList(Relocs, Addr);
825 ExternalSymbolRelocations.erase(i);
829 //===----------------------------------------------------------------------===//
830 // RuntimeDyld class implementation
832 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
833 StringRef SectionName) const {
834 for (unsigned I = BeginIdx; I != EndIdx; ++I)
835 if (RTDyld.Sections[I].Name == SectionName)
836 return RTDyld.Sections[I].LoadAddress;
841 void RuntimeDyld::MemoryManager::anchor() {}
842 void RuntimeDyld::SymbolResolver::anchor() {}
844 RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
845 RuntimeDyld::SymbolResolver &Resolver)
846 : MemMgr(MemMgr), Resolver(Resolver) {
847 // FIXME: There's a potential issue lurking here if a single instance of
848 // RuntimeDyld is used to load multiple objects. The current implementation
849 // associates a single memory manager with a RuntimeDyld instance. Even
850 // though the public class spawns a new 'impl' instance for each load,
851 // they share a single memory manager. This can become a problem when page
852 // permissions are applied.
854 ProcessAllSections = false;
858 RuntimeDyld::~RuntimeDyld() {}
860 static std::unique_ptr<RuntimeDyldCOFF>
861 createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
862 RuntimeDyld::SymbolResolver &Resolver,
863 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
864 std::unique_ptr<RuntimeDyldCOFF> Dyld =
865 RuntimeDyldCOFF::create(Arch, MM, Resolver);
866 Dyld->setProcessAllSections(ProcessAllSections);
867 Dyld->setRuntimeDyldChecker(Checker);
871 static std::unique_ptr<RuntimeDyldELF>
872 createRuntimeDyldELF(RuntimeDyld::MemoryManager &MM,
873 RuntimeDyld::SymbolResolver &Resolver,
874 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
875 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver));
876 Dyld->setProcessAllSections(ProcessAllSections);
877 Dyld->setRuntimeDyldChecker(Checker);
881 static std::unique_ptr<RuntimeDyldMachO>
882 createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
883 RuntimeDyld::SymbolResolver &Resolver,
884 bool ProcessAllSections,
885 RuntimeDyldCheckerImpl *Checker) {
886 std::unique_ptr<RuntimeDyldMachO> Dyld =
887 RuntimeDyldMachO::create(Arch, MM, Resolver);
888 Dyld->setProcessAllSections(ProcessAllSections);
889 Dyld->setRuntimeDyldChecker(Checker);
893 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
894 RuntimeDyld::loadObject(const ObjectFile &Obj) {
897 Dyld = createRuntimeDyldELF(MemMgr, Resolver, ProcessAllSections, Checker);
898 else if (Obj.isMachO())
899 Dyld = createRuntimeDyldMachO(
900 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
901 ProcessAllSections, Checker);
902 else if (Obj.isCOFF())
903 Dyld = createRuntimeDyldCOFF(
904 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
905 ProcessAllSections, Checker);
907 report_fatal_error("Incompatible object format!");
910 if (!Dyld->isCompatibleFile(Obj))
911 report_fatal_error("Incompatible object format!");
913 return Dyld->loadObject(Obj);
916 void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
919 return Dyld->getSymbolLocalAddress(Name);
922 RuntimeDyld::SymbolInfo RuntimeDyld::getSymbol(StringRef Name) const {
925 return Dyld->getSymbol(Name);
928 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
930 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
931 Dyld->reassignSectionAddress(SectionID, Addr);
934 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
935 uint64_t TargetAddress) {
936 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
939 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
941 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
943 void RuntimeDyld::registerEHFrames() {
945 Dyld->registerEHFrames();
948 void RuntimeDyld::deregisterEHFrames() {
950 Dyld->deregisterEHFrames();
953 } // end namespace llvm