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 // Print out the sections prior to relocation.
87 for (int i = 0, e = Sections.size(); i != e; ++i)
88 dumpSectionMemory(Sections[i], "before relocations");
91 // First, resolve relocations associated with external symbols.
92 resolveExternalSymbols();
94 // Just iterate over the sections we have and resolve all the relocations
95 // in them. Gross overkill, but it gets the job done.
96 for (int i = 0, e = Sections.size(); i != e; ++i) {
97 // The Section here (Sections[i]) refers to the section in which the
98 // symbol for the relocation is located. The SectionID in the relocation
99 // entry provides the section to which the relocation will be applied.
100 uint64_t Addr = Sections[i].LoadAddress;
101 DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t"
102 << format("%p", (uintptr_t)Addr) << "\n");
103 resolveRelocationList(Relocations[i], Addr);
104 Relocations.erase(i);
107 // Print out sections after relocation.
109 for (int i = 0, e = Sections.size(); i != e; ++i)
110 dumpSectionMemory(Sections[i], "after relocations");
115 void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress,
116 uint64_t TargetAddress) {
117 MutexGuard locked(lock);
118 for (unsigned i = 0, e = Sections.size(); i != e; ++i) {
119 if (Sections[i].Address == LocalAddress) {
120 reassignSectionAddress(i, TargetAddress);
124 llvm_unreachable("Attempting to remap address of unknown section!");
127 static std::error_code getOffset(const SymbolRef &Sym, SectionRef Sec,
129 ErrorOr<uint64_t> AddressOrErr = Sym.getAddress();
130 if (std::error_code EC = AddressOrErr.getError())
132 Result = *AddressOrErr - Sec.getAddress();
133 return std::error_code();
136 RuntimeDyldImpl::ObjSectionToIDMap
137 RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) {
138 MutexGuard locked(lock);
140 // Save information about our target
141 Arch = (Triple::ArchType)Obj.getArch();
142 IsTargetLittleEndian = Obj.isLittleEndian();
145 // Compute the memory size required to load all sections to be loaded
146 // and pass this information to the memory manager
147 if (MemMgr.needsToReserveAllocationSpace()) {
148 uint64_t CodeSize = 0, DataSizeRO = 0, DataSizeRW = 0;
149 computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW);
150 MemMgr.reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW);
153 // Used sections from the object file
154 ObjSectionToIDMap LocalSections;
156 // Common symbols requiring allocation, with their sizes and alignments
157 CommonSymbolList CommonSymbols;
160 DEBUG(dbgs() << "Parse symbols:\n");
161 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
163 uint32_t Flags = I->getFlags();
165 bool IsCommon = Flags & SymbolRef::SF_Common;
167 CommonSymbols.push_back(*I);
169 object::SymbolRef::Type SymType = I->getType();
171 if (SymType == object::SymbolRef::ST_Function ||
172 SymType == object::SymbolRef::ST_Data ||
173 SymType == object::SymbolRef::ST_Unknown) {
175 ErrorOr<StringRef> NameOrErr = I->getName();
176 Check(NameOrErr.getError());
177 StringRef Name = *NameOrErr;
178 ErrorOr<section_iterator> SIOrErr = I->getSection();
179 Check(SIOrErr.getError());
180 section_iterator SI = *SIOrErr;
181 if (SI == Obj.section_end())
184 Check(getOffset(*I, *SI, SectOffset));
185 StringRef SectionData;
186 Check(SI->getContents(SectionData));
187 bool IsCode = SI->isText();
189 findOrEmitSection(Obj, *SI, IsCode, LocalSections);
190 DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name
191 << " SID: " << SectionID << " Offset: "
192 << format("%p", (uintptr_t)SectOffset)
193 << " flags: " << Flags << "\n");
194 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
195 if (Flags & SymbolRef::SF_Weak)
196 RTDyldSymFlags |= JITSymbolFlags::Weak;
197 if (Flags & SymbolRef::SF_Exported)
198 RTDyldSymFlags |= JITSymbolFlags::Exported;
199 GlobalSymbolTable[Name] =
200 SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags);
205 // Allocate common symbols
206 emitCommonSymbols(Obj, CommonSymbols);
208 // Parse and process relocations
209 DEBUG(dbgs() << "Parse relocations:\n");
210 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
212 unsigned SectionID = 0;
214 section_iterator RelocatedSection = SI->getRelocatedSection();
216 if (RelocatedSection == SE)
219 relocation_iterator I = SI->relocation_begin();
220 relocation_iterator E = SI->relocation_end();
222 if (I == E && !ProcessAllSections)
225 bool IsCode = RelocatedSection->isText();
227 findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections);
228 DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n");
231 I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs);
233 // If there is an attached checker, notify it about the stubs for this
234 // section so that they can be verified.
236 Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs);
239 // Give the subclasses a chance to tie-up any loose ends.
240 finalizeLoad(Obj, LocalSections);
242 // for (auto E : LocalSections)
243 // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
245 return LocalSections;
248 // A helper method for computeTotalAllocSize.
249 // Computes the memory size required to allocate sections with the given sizes,
250 // assuming that all sections are allocated with the given alignment
252 computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes,
253 uint64_t Alignment) {
254 uint64_t TotalSize = 0;
255 for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) {
256 uint64_t AlignedSize =
257 (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment;
258 TotalSize += AlignedSize;
263 static bool isRequiredForExecution(const SectionRef Section) {
264 const ObjectFile *Obj = Section.getObject();
265 if (isa<object::ELFObjectFileBase>(Obj))
266 return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC;
267 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) {
268 const coff_section *CoffSection = COFFObj->getCOFFSection(Section);
269 // Avoid loading zero-sized COFF sections.
270 // In PE files, VirtualSize gives the section size, and SizeOfRawData
271 // may be zero for sections with content. In Obj files, SizeOfRawData
272 // gives the section size, and VirtualSize is always zero. Hence
273 // the need to check for both cases below.
274 bool HasContent = (CoffSection->VirtualSize > 0)
275 || (CoffSection->SizeOfRawData > 0);
276 bool IsDiscardable = CoffSection->Characteristics &
277 (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO);
278 return HasContent && !IsDiscardable;
281 assert(isa<MachOObjectFile>(Obj));
285 static bool isReadOnlyData(const SectionRef Section) {
286 const ObjectFile *Obj = Section.getObject();
287 if (isa<object::ELFObjectFileBase>(Obj))
288 return !(ELFSectionRef(Section).getFlags() &
289 (ELF::SHF_WRITE | ELF::SHF_EXECINSTR));
290 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
291 return ((COFFObj->getCOFFSection(Section)->Characteristics &
292 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
293 | COFF::IMAGE_SCN_MEM_READ
294 | COFF::IMAGE_SCN_MEM_WRITE))
296 (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA
297 | COFF::IMAGE_SCN_MEM_READ));
299 assert(isa<MachOObjectFile>(Obj));
303 static bool isZeroInit(const SectionRef Section) {
304 const ObjectFile *Obj = Section.getObject();
305 if (isa<object::ELFObjectFileBase>(Obj))
306 return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS;
307 if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj))
308 return COFFObj->getCOFFSection(Section)->Characteristics &
309 COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA;
311 auto *MachO = cast<MachOObjectFile>(Obj);
312 unsigned SectionType = MachO->getSectionType(Section);
313 return SectionType == MachO::S_ZEROFILL ||
314 SectionType == MachO::S_GB_ZEROFILL;
317 // Compute an upper bound of the memory size that is required to load all
319 void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj,
321 uint64_t &DataSizeRO,
322 uint64_t &DataSizeRW) {
323 // Compute the size of all sections required for execution
324 std::vector<uint64_t> CodeSectionSizes;
325 std::vector<uint64_t> ROSectionSizes;
326 std::vector<uint64_t> RWSectionSizes;
327 uint64_t MaxAlignment = sizeof(void *);
329 // Collect sizes of all sections to be loaded;
330 // also determine the max alignment of all sections
331 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
333 const SectionRef &Section = *SI;
335 bool IsRequired = isRequiredForExecution(Section);
337 // Consider only the sections that are required to be loaded for execution
340 uint64_t DataSize = Section.getSize();
341 uint64_t Alignment64 = Section.getAlignment();
342 bool IsCode = Section.isText();
343 bool IsReadOnly = isReadOnlyData(Section);
344 Check(Section.getName(Name));
345 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
347 uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section);
348 uint64_t SectionSize = DataSize + StubBufSize;
350 // The .eh_frame section (at least on Linux) needs an extra four bytes
352 // with zeroes added at the end. For MachO objects, this section has a
353 // slightly different name, so this won't have any effect for MachO
355 if (Name == ".eh_frame")
362 CodeSectionSizes.push_back(SectionSize);
363 } else if (IsReadOnly) {
364 ROSectionSizes.push_back(SectionSize);
366 RWSectionSizes.push_back(SectionSize);
369 // update the max alignment
370 if (Alignment > MaxAlignment) {
371 MaxAlignment = Alignment;
376 // Compute the size of all common symbols
377 uint64_t CommonSize = 0;
378 for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E;
380 uint32_t Flags = I->getFlags();
381 if (Flags & SymbolRef::SF_Common) {
382 // Add the common symbols to a list. We'll allocate them all below.
383 uint64_t Size = I->getCommonSize();
387 if (CommonSize != 0) {
388 RWSectionSizes.push_back(CommonSize);
391 // Compute the required allocation space for each different type of sections
392 // (code, read-only data, read-write data) assuming that all sections are
393 // allocated with the max alignment. Note that we cannot compute with the
394 // individual alignments of the sections, because then the required size
395 // depends on the order, in which the sections are allocated.
396 CodeSize = computeAllocationSizeForSections(CodeSectionSizes, MaxAlignment);
397 DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment);
398 DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment);
401 // compute stub buffer size for the given section
402 unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj,
403 const SectionRef &Section) {
404 unsigned StubSize = getMaxStubSize();
408 // FIXME: this is an inefficient way to handle this. We should computed the
409 // necessary section allocation size in loadObject by walking all the sections
411 unsigned StubBufSize = 0;
412 for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end();
414 section_iterator RelSecI = SI->getRelocatedSection();
415 if (!(RelSecI == Section))
418 for (const RelocationRef &Reloc : SI->relocations()) {
420 StubBufSize += StubSize;
424 // Get section data size and alignment
425 uint64_t DataSize = Section.getSize();
426 uint64_t Alignment64 = Section.getAlignment();
428 // Add stubbuf size alignment
429 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
430 unsigned StubAlignment = getStubAlignment();
431 unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment);
432 if (StubAlignment > EndAlignment)
433 StubBufSize += StubAlignment - EndAlignment;
437 uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src,
438 unsigned Size) const {
440 if (IsTargetLittleEndian) {
443 Result = (Result << 8) | *Src--;
446 Result = (Result << 8) | *Src++;
451 void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst,
452 unsigned Size) const {
453 if (IsTargetLittleEndian) {
455 *Dst++ = Value & 0xFF;
461 *Dst-- = Value & 0xFF;
467 void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj,
468 CommonSymbolList &CommonSymbols) {
469 if (CommonSymbols.empty())
472 uint64_t CommonSize = 0;
473 CommonSymbolList SymbolsToAllocate;
475 DEBUG(dbgs() << "Processing common symbols...\n");
477 for (const auto &Sym : CommonSymbols) {
478 ErrorOr<StringRef> NameOrErr = Sym.getName();
479 Check(NameOrErr.getError());
480 StringRef Name = *NameOrErr;
482 // Skip common symbols already elsewhere.
483 if (GlobalSymbolTable.count(Name) ||
484 Resolver.findSymbolInLogicalDylib(Name)) {
485 DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name
490 uint32_t Align = Sym.getAlignment();
491 uint64_t Size = Sym.getCommonSize();
493 CommonSize += Align + Size;
494 SymbolsToAllocate.push_back(Sym);
497 // Allocate memory for the section
498 unsigned SectionID = Sections.size();
499 uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *),
500 SectionID, StringRef(), false);
502 report_fatal_error("Unable to allocate memory for common symbols!");
504 Sections.push_back(SectionEntry("<common symbols>", Addr, CommonSize, 0));
505 memset(Addr, 0, CommonSize);
507 DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: "
508 << format("%p", Addr) << " DataSize: " << CommonSize << "\n");
510 // Assign the address of each symbol
511 for (auto &Sym : SymbolsToAllocate) {
512 uint32_t Align = Sym.getAlignment();
513 uint64_t Size = Sym.getCommonSize();
514 ErrorOr<StringRef> NameOrErr = Sym.getName();
515 Check(NameOrErr.getError());
516 StringRef Name = *NameOrErr;
518 // This symbol has an alignment requirement.
519 uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align);
521 Offset += AlignOffset;
523 uint32_t Flags = Sym.getFlags();
524 JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None;
525 if (Flags & SymbolRef::SF_Weak)
526 RTDyldSymFlags |= JITSymbolFlags::Weak;
527 if (Flags & SymbolRef::SF_Exported)
528 RTDyldSymFlags |= JITSymbolFlags::Exported;
529 DEBUG(dbgs() << "Allocating common symbol " << Name << " address "
530 << format("%p", Addr) << "\n");
531 GlobalSymbolTable[Name] =
532 SymbolTableEntry(SectionID, Offset, RTDyldSymFlags);
538 Checker->registerSection(Obj.getFileName(), SectionID);
541 unsigned RuntimeDyldImpl::emitSection(const ObjectFile &Obj,
542 const SectionRef &Section, bool IsCode) {
545 uint64_t Alignment64 = Section.getAlignment();
547 unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL;
548 unsigned PaddingSize = 0;
549 unsigned StubBufSize = 0;
551 bool IsRequired = isRequiredForExecution(Section);
552 bool IsVirtual = Section.isVirtual();
553 bool IsZeroInit = isZeroInit(Section);
554 bool IsReadOnly = isReadOnlyData(Section);
555 uint64_t DataSize = Section.getSize();
556 Check(Section.getName(Name));
558 StubBufSize = computeSectionStubBufSize(Obj, Section);
560 // The .eh_frame section (at least on Linux) needs an extra four bytes padded
561 // with zeroes added at the end. For MachO objects, this section has a
562 // slightly different name, so this won't have any effect for MachO objects.
563 if (Name == ".eh_frame")
567 unsigned SectionID = Sections.size();
569 const char *pData = nullptr;
571 // In either case, set the location of the unrelocated section in memory,
572 // since we still process relocations for it even if we're not applying them.
573 Check(Section.getContents(data));
574 // Virtual sections have no data in the object image, so leave pData = 0
578 // Code section alignment needs to be at least as high as stub alignment or
579 // padding calculations may by incorrect when the section is remapped to a
582 Alignment = std::max(Alignment, getStubAlignment());
584 // Some sections, such as debug info, don't need to be loaded for execution.
585 // Leave those where they are.
587 Allocate = DataSize + PaddingSize + StubBufSize;
590 Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID,
592 : MemMgr.allocateDataSection(Allocate, Alignment, SectionID,
595 report_fatal_error("Unable to allocate section memory!");
597 // Zero-initialize or copy the data from the image
598 if (IsZeroInit || IsVirtual)
599 memset(Addr, 0, DataSize);
601 memcpy(Addr, pData, DataSize);
603 // Fill in any extra bytes we allocated for padding
604 if (PaddingSize != 0) {
605 memset(Addr + DataSize, 0, PaddingSize);
606 // Update the DataSize variable so that the stub offset is set correctly.
607 DataSize += PaddingSize;
610 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
611 << " obj addr: " << format("%p", pData)
612 << " new addr: " << format("%p", Addr)
613 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
614 << " Allocate: " << Allocate << "\n");
616 // Even if we didn't load the section, we need to record an entry for it
617 // to handle later processing (and by 'handle' I mean don't do anything
618 // with these sections).
621 DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name
622 << " obj addr: " << format("%p", data.data()) << " new addr: 0"
623 << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize
624 << " Allocate: " << Allocate << "\n");
627 Sections.push_back(SectionEntry(Name, Addr, DataSize, (uintptr_t)pData));
630 Checker->registerSection(Obj.getFileName(), SectionID);
635 unsigned RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj,
636 const SectionRef &Section,
638 ObjSectionToIDMap &LocalSections) {
640 unsigned SectionID = 0;
641 ObjSectionToIDMap::iterator i = LocalSections.find(Section);
642 if (i != LocalSections.end())
643 SectionID = i->second;
645 SectionID = emitSection(Obj, Section, IsCode);
646 LocalSections[Section] = SectionID;
651 void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE,
652 unsigned SectionID) {
653 Relocations[SectionID].push_back(RE);
656 void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE,
657 StringRef SymbolName) {
658 // Relocation by symbol. If the symbol is found in the global symbol table,
659 // create an appropriate section relocation. Otherwise, add it to
660 // ExternalSymbolRelocations.
661 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName);
662 if (Loc == GlobalSymbolTable.end()) {
663 ExternalSymbolRelocations[SymbolName].push_back(RE);
665 // Copy the RE since we want to modify its addend.
666 RelocationEntry RECopy = RE;
667 const auto &SymInfo = Loc->second;
668 RECopy.Addend += SymInfo.getOffset();
669 Relocations[SymInfo.getSectionID()].push_back(RECopy);
673 uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr,
674 unsigned AbiVariant) {
675 if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) {
676 // This stub has to be able to access the full address space,
677 // since symbol lookup won't necessarily find a handy, in-range,
678 // PLT stub for functions which could be anywhere.
679 // Stub can use ip0 (== x16) to calculate address
680 writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr>
681 writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr>
682 writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr>
683 writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr>
684 writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0
687 } else if (Arch == Triple::arm || Arch == Triple::armeb) {
688 // TODO: There is only ARM far stub now. We should add the Thumb stub,
689 // and stubs for branches Thumb - ARM and ARM - Thumb.
690 writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label>
692 } else if (IsMipsO32ABI) {
693 // 0: 3c190000 lui t9,%hi(addr).
694 // 4: 27390000 addiu t9,t9,%lo(addr).
695 // 8: 03200008 jr t9.
697 const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000;
698 const unsigned JrT9Instr = 0x03200008, NopInstr = 0x0;
700 writeBytesUnaligned(LuiT9Instr, Addr, 4);
701 writeBytesUnaligned(AdduiT9Instr, Addr+4, 4);
702 writeBytesUnaligned(JrT9Instr, Addr+8, 4);
703 writeBytesUnaligned(NopInstr, Addr+12, 4);
705 } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) {
706 // Depending on which version of the ELF ABI is in use, we need to
707 // generate one of two variants of the stub. They both start with
708 // the same sequence to load the target address into r12.
709 writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr)
710 writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr)
711 writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32
712 writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr)
713 writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr)
714 if (AbiVariant == 2) {
715 // PowerPC64 stub ELFv2 ABI: The address points to the function itself.
716 // The address is already in r12 as required by the ABI. Branch to it.
717 writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1)
718 writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12
719 writeInt32BE(Addr+28, 0x4E800420); // bctr
721 // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor.
722 // Load the function address on r11 and sets it to control register. Also
723 // loads the function TOC in r2 and environment pointer to r11.
724 writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1)
725 writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12)
726 writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12)
727 writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11
728 writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2)
729 writeInt32BE(Addr+40, 0x4E800420); // bctr
732 } else if (Arch == Triple::systemz) {
733 writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8
734 writeInt16BE(Addr+2, 0x0000);
735 writeInt16BE(Addr+4, 0x0004);
736 writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1
737 // 8-byte address stored at Addr + 8
739 } else if (Arch == Triple::x86_64) {
741 *(Addr+1) = 0x25; // rip
742 // 32-bit PC-relative address of the GOT entry will be stored at Addr+2
743 } else if (Arch == Triple::x86) {
744 *Addr = 0xE9; // 32-bit pc-relative jump.
749 // Assign an address to a symbol name and resolve all the relocations
750 // associated with it.
751 void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID,
753 // The address to use for relocation resolution is not
754 // the address of the local section buffer. We must be doing
755 // a remote execution environment of some sort. Relocations can't
756 // be applied until all the sections have been moved. The client must
757 // trigger this with a call to MCJIT::finalize() or
758 // RuntimeDyld::resolveRelocations().
760 // Addr is a uint64_t because we can't assume the pointer width
761 // of the target is the same as that of the host. Just use a generic
762 // "big enough" type.
763 DEBUG(dbgs() << "Reassigning address for section "
764 << SectionID << " (" << Sections[SectionID].Name << "): "
765 << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> "
766 << format("0x%016" PRIx64, Addr) << "\n");
767 Sections[SectionID].LoadAddress = Addr;
770 void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs,
772 for (unsigned i = 0, e = Relocs.size(); i != e; ++i) {
773 const RelocationEntry &RE = Relocs[i];
774 // Ignore relocations for sections that were not loaded
775 if (Sections[RE.SectionID].Address == nullptr)
777 resolveRelocation(RE, Value);
781 void RuntimeDyldImpl::resolveExternalSymbols() {
782 while (!ExternalSymbolRelocations.empty()) {
783 StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin();
785 StringRef Name = i->first();
786 if (Name.size() == 0) {
787 // This is an absolute symbol, use an address of zero.
788 DEBUG(dbgs() << "Resolving absolute relocations."
790 RelocationList &Relocs = i->second;
791 resolveRelocationList(Relocs, 0);
794 RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name);
795 if (Loc == GlobalSymbolTable.end()) {
796 // This is an external symbol, try to get its address from the symbol
798 Addr = Resolver.findSymbol(Name.data()).getAddress();
799 // The call to getSymbolAddress may have caused additional modules to
800 // be loaded, which may have added new entries to the
801 // ExternalSymbolRelocations map. Consquently, we need to update our
802 // iterator. This is also why retrieval of the relocation list
803 // associated with this symbol is deferred until below this point.
804 // New entries may have been added to the relocation list.
805 i = ExternalSymbolRelocations.find(Name);
807 // We found the symbol in our global table. It was probably in a
808 // Module that we loaded previously.
809 const auto &SymInfo = Loc->second;
810 Addr = getSectionLoadAddress(SymInfo.getSectionID()) +
814 // FIXME: Implement error handling that doesn't kill the host program!
816 report_fatal_error("Program used external function '" + Name +
817 "' which could not be resolved!");
819 // If Resolver returned UINT64_MAX, the client wants to handle this symbol
820 // manually and we shouldn't resolve its relocations.
821 if (Addr != UINT64_MAX) {
822 DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t"
823 << format("0x%lx", Addr) << "\n");
824 // This list may have been updated when we called getSymbolAddress, so
825 // don't change this code to get the list earlier.
826 RelocationList &Relocs = i->second;
827 resolveRelocationList(Relocs, Addr);
831 ExternalSymbolRelocations.erase(i);
835 //===----------------------------------------------------------------------===//
836 // RuntimeDyld class implementation
838 uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress(
839 const object::SectionRef &Sec) const {
841 // llvm::dbgs() << "Searching for " << Sec.getRawDataRefImpl() << " in:\n";
842 // for (auto E : ObjSecToIDMap)
843 // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n";
845 auto I = ObjSecToIDMap.find(Sec);
846 if (I != ObjSecToIDMap.end()) {
847 // llvm::dbgs() << "Found ID " << I->second << " for Sec: " << Sec.getRawDataRefImpl() << ", LoadAddress = " << RTDyld.Sections[I->second].LoadAddress << "\n";
848 return RTDyld.Sections[I->second].LoadAddress;
850 // llvm::dbgs() << "Not found.\n";
856 void RuntimeDyld::MemoryManager::anchor() {}
857 void RuntimeDyld::SymbolResolver::anchor() {}
859 RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr,
860 RuntimeDyld::SymbolResolver &Resolver)
861 : MemMgr(MemMgr), Resolver(Resolver) {
862 // FIXME: There's a potential issue lurking here if a single instance of
863 // RuntimeDyld is used to load multiple objects. The current implementation
864 // associates a single memory manager with a RuntimeDyld instance. Even
865 // though the public class spawns a new 'impl' instance for each load,
866 // they share a single memory manager. This can become a problem when page
867 // permissions are applied.
869 ProcessAllSections = false;
873 RuntimeDyld::~RuntimeDyld() {}
875 static std::unique_ptr<RuntimeDyldCOFF>
876 createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
877 RuntimeDyld::SymbolResolver &Resolver,
878 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
879 std::unique_ptr<RuntimeDyldCOFF> Dyld =
880 RuntimeDyldCOFF::create(Arch, MM, Resolver);
881 Dyld->setProcessAllSections(ProcessAllSections);
882 Dyld->setRuntimeDyldChecker(Checker);
886 static std::unique_ptr<RuntimeDyldELF>
887 createRuntimeDyldELF(RuntimeDyld::MemoryManager &MM,
888 RuntimeDyld::SymbolResolver &Resolver,
889 bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) {
890 std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver));
891 Dyld->setProcessAllSections(ProcessAllSections);
892 Dyld->setRuntimeDyldChecker(Checker);
896 static std::unique_ptr<RuntimeDyldMachO>
897 createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM,
898 RuntimeDyld::SymbolResolver &Resolver,
899 bool ProcessAllSections,
900 RuntimeDyldCheckerImpl *Checker) {
901 std::unique_ptr<RuntimeDyldMachO> Dyld =
902 RuntimeDyldMachO::create(Arch, MM, Resolver);
903 Dyld->setProcessAllSections(ProcessAllSections);
904 Dyld->setRuntimeDyldChecker(Checker);
908 std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
909 RuntimeDyld::loadObject(const ObjectFile &Obj) {
912 Dyld = createRuntimeDyldELF(MemMgr, Resolver, ProcessAllSections, Checker);
913 else if (Obj.isMachO())
914 Dyld = createRuntimeDyldMachO(
915 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
916 ProcessAllSections, Checker);
917 else if (Obj.isCOFF())
918 Dyld = createRuntimeDyldCOFF(
919 static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver,
920 ProcessAllSections, Checker);
922 report_fatal_error("Incompatible object format!");
925 if (!Dyld->isCompatibleFile(Obj))
926 report_fatal_error("Incompatible object format!");
928 return Dyld->loadObject(Obj);
931 void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const {
934 return Dyld->getSymbolLocalAddress(Name);
937 RuntimeDyld::SymbolInfo RuntimeDyld::getSymbol(StringRef Name) const {
940 return Dyld->getSymbol(Name);
943 void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); }
945 void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) {
946 Dyld->reassignSectionAddress(SectionID, Addr);
949 void RuntimeDyld::mapSectionAddress(const void *LocalAddress,
950 uint64_t TargetAddress) {
951 Dyld->mapSectionAddress(LocalAddress, TargetAddress);
954 bool RuntimeDyld::hasError() { return Dyld->hasError(); }
956 StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); }
958 void RuntimeDyld::registerEHFrames() {
960 Dyld->registerEHFrames();
963 void RuntimeDyld::deregisterEHFrames() {
965 Dyld->deregisterEHFrames();
968 } // end namespace llvm