| //===-- RuntimeDyld.cpp - Run-time dynamic linker for MC-JIT ----*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Implementation of the MC-JIT runtime dynamic linker. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/ExecutionEngine/RuntimeDyld.h" |
| #include "RuntimeDyldCOFF.h" |
| #include "RuntimeDyldCheckerImpl.h" |
| #include "RuntimeDyldELF.h" |
| #include "RuntimeDyldImpl.h" |
| #include "RuntimeDyldMachO.h" |
| #include "llvm/Object/COFF.h" |
| #include "llvm/Object/ELFObjectFile.h" |
| #include "llvm/Support/ManagedStatic.h" |
| #include "llvm/Support/MathExtras.h" |
| #include "llvm/Support/MutexGuard.h" |
| |
| using namespace llvm; |
| using namespace llvm::object; |
| |
| #define DEBUG_TYPE "dyld" |
| |
| namespace { |
| |
| enum RuntimeDyldErrorCode { |
| GenericRTDyldError = 1 |
| }; |
| |
| // FIXME: This class is only here to support the transition to llvm::Error. It |
| // will be removed once this transition is complete. Clients should prefer to |
| // deal with the Error value directly, rather than converting to error_code. |
| class RuntimeDyldErrorCategory : public std::error_category { |
| public: |
| const char *name() const noexcept override { return "runtimedyld"; } |
| |
| std::string message(int Condition) const override { |
| switch (static_cast<RuntimeDyldErrorCode>(Condition)) { |
| case GenericRTDyldError: return "Generic RuntimeDyld error"; |
| } |
| llvm_unreachable("Unrecognized RuntimeDyldErrorCode"); |
| } |
| }; |
| |
| static ManagedStatic<RuntimeDyldErrorCategory> RTDyldErrorCategory; |
| |
| } |
| |
| char RuntimeDyldError::ID = 0; |
| |
| void RuntimeDyldError::log(raw_ostream &OS) const { |
| OS << ErrMsg << "\n"; |
| } |
| |
| std::error_code RuntimeDyldError::convertToErrorCode() const { |
| return std::error_code(GenericRTDyldError, *RTDyldErrorCategory); |
| } |
| |
| // Empty out-of-line virtual destructor as the key function. |
| RuntimeDyldImpl::~RuntimeDyldImpl() {} |
| |
| // Pin LoadedObjectInfo's vtables to this file. |
| void RuntimeDyld::LoadedObjectInfo::anchor() {} |
| |
| namespace llvm { |
| |
| void RuntimeDyldImpl::registerEHFrames() {} |
| |
| void RuntimeDyldImpl::deregisterEHFrames() { |
| MemMgr.deregisterEHFrames(); |
| } |
| |
| #ifndef NDEBUG |
| static void dumpSectionMemory(const SectionEntry &S, StringRef State) { |
| dbgs() << "----- Contents of section " << S.getName() << " " << State |
| << " -----"; |
| |
| if (S.getAddress() == nullptr) { |
| dbgs() << "\n <section not emitted>\n"; |
| return; |
| } |
| |
| const unsigned ColsPerRow = 16; |
| |
| uint8_t *DataAddr = S.getAddress(); |
| uint64_t LoadAddr = S.getLoadAddress(); |
| |
| unsigned StartPadding = LoadAddr & (ColsPerRow - 1); |
| unsigned BytesRemaining = S.getSize(); |
| |
| if (StartPadding) { |
| dbgs() << "\n" << format("0x%016" PRIx64, |
| LoadAddr & ~(uint64_t)(ColsPerRow - 1)) << ":"; |
| while (StartPadding--) |
| dbgs() << " "; |
| } |
| |
| while (BytesRemaining > 0) { |
| if ((LoadAddr & (ColsPerRow - 1)) == 0) |
| dbgs() << "\n" << format("0x%016" PRIx64, LoadAddr) << ":"; |
| |
| dbgs() << " " << format("%02x", *DataAddr); |
| |
| ++DataAddr; |
| ++LoadAddr; |
| --BytesRemaining; |
| } |
| |
| dbgs() << "\n"; |
| } |
| #endif |
| |
| // Resolve the relocations for all symbols we currently know about. |
| void RuntimeDyldImpl::resolveRelocations() { |
| MutexGuard locked(lock); |
| |
| // Print out the sections prior to relocation. |
| DEBUG( |
| for (int i = 0, e = Sections.size(); i != e; ++i) |
| dumpSectionMemory(Sections[i], "before relocations"); |
| ); |
| |
| // First, resolve relocations associated with external symbols. |
| resolveExternalSymbols(); |
| |
| // Iterate over all outstanding relocations |
| for (auto it = Relocations.begin(), e = Relocations.end(); it != e; ++it) { |
| // The Section here (Sections[i]) refers to the section in which the |
| // symbol for the relocation is located. The SectionID in the relocation |
| // entry provides the section to which the relocation will be applied. |
| int Idx = it->first; |
| uint64_t Addr = Sections[Idx].getLoadAddress(); |
| DEBUG(dbgs() << "Resolving relocations Section #" << Idx << "\t" |
| << format("%p", (uintptr_t)Addr) << "\n"); |
| resolveRelocationList(it->second, Addr); |
| } |
| Relocations.clear(); |
| |
| // Print out sections after relocation. |
| DEBUG( |
| for (int i = 0, e = Sections.size(); i != e; ++i) |
| dumpSectionMemory(Sections[i], "after relocations"); |
| ); |
| |
| } |
| |
| void RuntimeDyldImpl::mapSectionAddress(const void *LocalAddress, |
| uint64_t TargetAddress) { |
| MutexGuard locked(lock); |
| for (unsigned i = 0, e = Sections.size(); i != e; ++i) { |
| if (Sections[i].getAddress() == LocalAddress) { |
| reassignSectionAddress(i, TargetAddress); |
| return; |
| } |
| } |
| llvm_unreachable("Attempting to remap address of unknown section!"); |
| } |
| |
| static Error getOffset(const SymbolRef &Sym, SectionRef Sec, |
| uint64_t &Result) { |
| Expected<uint64_t> AddressOrErr = Sym.getAddress(); |
| if (!AddressOrErr) |
| return AddressOrErr.takeError(); |
| Result = *AddressOrErr - Sec.getAddress(); |
| return Error::success(); |
| } |
| |
| Expected<RuntimeDyldImpl::ObjSectionToIDMap> |
| RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) { |
| MutexGuard locked(lock); |
| |
| // Save information about our target |
| Arch = (Triple::ArchType)Obj.getArch(); |
| IsTargetLittleEndian = Obj.isLittleEndian(); |
| setMipsABI(Obj); |
| |
| // Compute the memory size required to load all sections to be loaded |
| // and pass this information to the memory manager |
| if (MemMgr.needsToReserveAllocationSpace()) { |
| uint64_t CodeSize = 0, RODataSize = 0, RWDataSize = 0; |
| uint32_t CodeAlign = 1, RODataAlign = 1, RWDataAlign = 1; |
| if (auto Err = computeTotalAllocSize(Obj, |
| CodeSize, CodeAlign, |
| RODataSize, RODataAlign, |
| RWDataSize, RWDataAlign)) |
| return std::move(Err); |
| MemMgr.reserveAllocationSpace(CodeSize, CodeAlign, RODataSize, RODataAlign, |
| RWDataSize, RWDataAlign); |
| } |
| |
| // Used sections from the object file |
| ObjSectionToIDMap LocalSections; |
| |
| // Common symbols requiring allocation, with their sizes and alignments |
| CommonSymbolList CommonSymbols; |
| |
| // Parse symbols |
| DEBUG(dbgs() << "Parse symbols:\n"); |
| for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E; |
| ++I) { |
| uint32_t Flags = I->getFlags(); |
| |
| // Skip undefined symbols. |
| if (Flags & SymbolRef::SF_Undefined) |
| continue; |
| |
| if (Flags & SymbolRef::SF_Common) |
| CommonSymbols.push_back(*I); |
| else { |
| |
| // Get the symbol type. |
| object::SymbolRef::Type SymType; |
| if (auto SymTypeOrErr = I->getType()) |
| SymType = *SymTypeOrErr; |
| else |
| return SymTypeOrErr.takeError(); |
| |
| // Get symbol name. |
| StringRef Name; |
| if (auto NameOrErr = I->getName()) |
| Name = *NameOrErr; |
| else |
| return NameOrErr.takeError(); |
| |
| // Compute JIT symbol flags. |
| JITSymbolFlags JITSymFlags = JITSymbolFlags::fromObjectSymbol(*I); |
| |
| // If this is a weak definition, check to see if there's a strong one. |
| // If there is, skip this symbol (we won't be providing it: the strong |
| // definition will). If there's no strong definition, make this definition |
| // strong. |
| if (JITSymFlags.isWeak()) { |
| // First check whether there's already a definition in this instance. |
| // FIXME: Override existing weak definitions with strong ones. |
| if (GlobalSymbolTable.count(Name)) |
| continue; |
| // Then check the symbol resolver to see if there's a definition |
| // elsewhere in this logical dylib. |
| if (auto Sym = Resolver.findSymbolInLogicalDylib(Name)) |
| if (Sym.getFlags().isStrongDefinition()) |
| continue; |
| // else |
| JITSymFlags &= ~JITSymbolFlags::Weak; |
| } |
| |
| if (Flags & SymbolRef::SF_Absolute && |
| SymType != object::SymbolRef::ST_File) { |
| uint64_t Addr = 0; |
| if (auto AddrOrErr = I->getAddress()) |
| Addr = *AddrOrErr; |
| else |
| return AddrOrErr.takeError(); |
| |
| unsigned SectionID = AbsoluteSymbolSection; |
| |
| DEBUG(dbgs() << "\tType: " << SymType << " (absolute) Name: " << Name |
| << " SID: " << SectionID << " Offset: " |
| << format("%p", (uintptr_t)Addr) |
| << " flags: " << Flags << "\n"); |
| GlobalSymbolTable[Name] = |
| SymbolTableEntry(SectionID, Addr, JITSymFlags); |
| } else if (SymType == object::SymbolRef::ST_Function || |
| SymType == object::SymbolRef::ST_Data || |
| SymType == object::SymbolRef::ST_Unknown || |
| SymType == object::SymbolRef::ST_Other) { |
| |
| section_iterator SI = Obj.section_end(); |
| if (auto SIOrErr = I->getSection()) |
| SI = *SIOrErr; |
| else |
| return SIOrErr.takeError(); |
| |
| if (SI == Obj.section_end()) |
| continue; |
| |
| // Get symbol offset. |
| uint64_t SectOffset; |
| if (auto Err = getOffset(*I, *SI, SectOffset)) |
| return std::move(Err); |
| |
| bool IsCode = SI->isText(); |
| unsigned SectionID; |
| if (auto SectionIDOrErr = findOrEmitSection(Obj, *SI, IsCode, |
| LocalSections)) |
| SectionID = *SectionIDOrErr; |
| else |
| return SectionIDOrErr.takeError(); |
| |
| DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name |
| << " SID: " << SectionID << " Offset: " |
| << format("%p", (uintptr_t)SectOffset) |
| << " flags: " << Flags << "\n"); |
| GlobalSymbolTable[Name] = |
| SymbolTableEntry(SectionID, SectOffset, JITSymFlags); |
| } |
| } |
| } |
| |
| // Allocate common symbols |
| if (auto Err = emitCommonSymbols(Obj, CommonSymbols)) |
| return std::move(Err); |
| |
| // Parse and process relocations |
| DEBUG(dbgs() << "Parse relocations:\n"); |
| for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); |
| SI != SE; ++SI) { |
| StubMap Stubs; |
| section_iterator RelocatedSection = SI->getRelocatedSection(); |
| |
| if (RelocatedSection == SE) |
| continue; |
| |
| relocation_iterator I = SI->relocation_begin(); |
| relocation_iterator E = SI->relocation_end(); |
| |
| if (I == E && !ProcessAllSections) |
| continue; |
| |
| bool IsCode = RelocatedSection->isText(); |
| unsigned SectionID = 0; |
| if (auto SectionIDOrErr = findOrEmitSection(Obj, *RelocatedSection, IsCode, |
| LocalSections)) |
| SectionID = *SectionIDOrErr; |
| else |
| return SectionIDOrErr.takeError(); |
| |
| DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n"); |
| |
| for (; I != E;) |
| if (auto IOrErr = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs)) |
| I = *IOrErr; |
| else |
| return IOrErr.takeError(); |
| |
| // If there is an attached checker, notify it about the stubs for this |
| // section so that they can be verified. |
| if (Checker) |
| Checker->registerStubMap(Obj.getFileName(), SectionID, Stubs); |
| } |
| |
| // Give the subclasses a chance to tie-up any loose ends. |
| if (auto Err = finalizeLoad(Obj, LocalSections)) |
| return std::move(Err); |
| |
| // for (auto E : LocalSections) |
| // llvm::dbgs() << "Added: " << E.first.getRawDataRefImpl() << " -> " << E.second << "\n"; |
| |
| return LocalSections; |
| } |
| |
| // A helper method for computeTotalAllocSize. |
| // Computes the memory size required to allocate sections with the given sizes, |
| // assuming that all sections are allocated with the given alignment |
| static uint64_t |
| computeAllocationSizeForSections(std::vector<uint64_t> &SectionSizes, |
| uint64_t Alignment) { |
| uint64_t TotalSize = 0; |
| for (size_t Idx = 0, Cnt = SectionSizes.size(); Idx < Cnt; Idx++) { |
| uint64_t AlignedSize = |
| (SectionSizes[Idx] + Alignment - 1) / Alignment * Alignment; |
| TotalSize += AlignedSize; |
| } |
| return TotalSize; |
| } |
| |
| static bool isRequiredForExecution(const SectionRef Section) { |
| const ObjectFile *Obj = Section.getObject(); |
| if (isa<object::ELFObjectFileBase>(Obj)) |
| return ELFSectionRef(Section).getFlags() & ELF::SHF_ALLOC; |
| if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) { |
| const coff_section *CoffSection = COFFObj->getCOFFSection(Section); |
| // Avoid loading zero-sized COFF sections. |
| // In PE files, VirtualSize gives the section size, and SizeOfRawData |
| // may be zero for sections with content. In Obj files, SizeOfRawData |
| // gives the section size, and VirtualSize is always zero. Hence |
| // the need to check for both cases below. |
| bool HasContent = |
| (CoffSection->VirtualSize > 0) || (CoffSection->SizeOfRawData > 0); |
| bool IsDiscardable = |
| CoffSection->Characteristics & |
| (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_LNK_INFO); |
| return HasContent && !IsDiscardable; |
| } |
| |
| assert(isa<MachOObjectFile>(Obj)); |
| return true; |
| } |
| |
| static bool isReadOnlyData(const SectionRef Section) { |
| const ObjectFile *Obj = Section.getObject(); |
| if (isa<object::ELFObjectFileBase>(Obj)) |
| return !(ELFSectionRef(Section).getFlags() & |
| (ELF::SHF_WRITE | ELF::SHF_EXECINSTR)); |
| if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) |
| return ((COFFObj->getCOFFSection(Section)->Characteristics & |
| (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
| | COFF::IMAGE_SCN_MEM_READ |
| | COFF::IMAGE_SCN_MEM_WRITE)) |
| == |
| (COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
| | COFF::IMAGE_SCN_MEM_READ)); |
| |
| assert(isa<MachOObjectFile>(Obj)); |
| return false; |
| } |
| |
| static bool isZeroInit(const SectionRef Section) { |
| const ObjectFile *Obj = Section.getObject(); |
| if (isa<object::ELFObjectFileBase>(Obj)) |
| return ELFSectionRef(Section).getType() == ELF::SHT_NOBITS; |
| if (auto *COFFObj = dyn_cast<object::COFFObjectFile>(Obj)) |
| return COFFObj->getCOFFSection(Section)->Characteristics & |
| COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA; |
| |
| auto *MachO = cast<MachOObjectFile>(Obj); |
| unsigned SectionType = MachO->getSectionType(Section); |
| return SectionType == MachO::S_ZEROFILL || |
| SectionType == MachO::S_GB_ZEROFILL; |
| } |
| |
| // Compute an upper bound of the memory size that is required to load all |
| // sections |
| Error RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj, |
| uint64_t &CodeSize, |
| uint32_t &CodeAlign, |
| uint64_t &RODataSize, |
| uint32_t &RODataAlign, |
| uint64_t &RWDataSize, |
| uint32_t &RWDataAlign) { |
| // Compute the size of all sections required for execution |
| std::vector<uint64_t> CodeSectionSizes; |
| std::vector<uint64_t> ROSectionSizes; |
| std::vector<uint64_t> RWSectionSizes; |
| |
| // Collect sizes of all sections to be loaded; |
| // also determine the max alignment of all sections |
| for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); |
| SI != SE; ++SI) { |
| const SectionRef &Section = *SI; |
| |
| bool IsRequired = isRequiredForExecution(Section) || ProcessAllSections; |
| |
| // Consider only the sections that are required to be loaded for execution |
| if (IsRequired) { |
| uint64_t DataSize = Section.getSize(); |
| uint64_t Alignment64 = Section.getAlignment(); |
| unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL; |
| bool IsCode = Section.isText(); |
| bool IsReadOnly = isReadOnlyData(Section); |
| |
| StringRef Name; |
| if (auto EC = Section.getName(Name)) |
| return errorCodeToError(EC); |
| |
| uint64_t StubBufSize = computeSectionStubBufSize(Obj, Section); |
| uint64_t SectionSize = DataSize + StubBufSize; |
| |
| // The .eh_frame section (at least on Linux) needs an extra four bytes |
| // padded |
| // with zeroes added at the end. For MachO objects, this section has a |
| // slightly different name, so this won't have any effect for MachO |
| // objects. |
| if (Name == ".eh_frame") |
| SectionSize += 4; |
| |
| if (!SectionSize) |
| SectionSize = 1; |
| |
| if (IsCode) { |
| CodeAlign = std::max(CodeAlign, Alignment); |
| CodeSectionSizes.push_back(SectionSize); |
| } else if (IsReadOnly) { |
| RODataAlign = std::max(RODataAlign, Alignment); |
| ROSectionSizes.push_back(SectionSize); |
| } else { |
| RWDataAlign = std::max(RWDataAlign, Alignment); |
| RWSectionSizes.push_back(SectionSize); |
| } |
| } |
| } |
| |
| // Compute Global Offset Table size. If it is not zero we |
| // also update alignment, which is equal to a size of a |
| // single GOT entry. |
| if (unsigned GotSize = computeGOTSize(Obj)) { |
| RWSectionSizes.push_back(GotSize); |
| RWDataAlign = std::max<uint32_t>(RWDataAlign, getGOTEntrySize()); |
| } |
| |
| // Compute the size of all common symbols |
| uint64_t CommonSize = 0; |
| uint32_t CommonAlign = 1; |
| for (symbol_iterator I = Obj.symbol_begin(), E = Obj.symbol_end(); I != E; |
| ++I) { |
| uint32_t Flags = I->getFlags(); |
| if (Flags & SymbolRef::SF_Common) { |
| // Add the common symbols to a list. We'll allocate them all below. |
| uint64_t Size = I->getCommonSize(); |
| uint32_t Align = I->getAlignment(); |
| // If this is the first common symbol, use its alignment as the alignment |
| // for the common symbols section. |
| if (CommonSize == 0) |
| CommonAlign = Align; |
| CommonSize = alignTo(CommonSize, Align) + Size; |
| } |
| } |
| if (CommonSize != 0) { |
| RWSectionSizes.push_back(CommonSize); |
| RWDataAlign = std::max(RWDataAlign, CommonAlign); |
| } |
| |
| // Compute the required allocation space for each different type of sections |
| // (code, read-only data, read-write data) assuming that all sections are |
| // allocated with the max alignment. Note that we cannot compute with the |
| // individual alignments of the sections, because then the required size |
| // depends on the order, in which the sections are allocated. |
| CodeSize = computeAllocationSizeForSections(CodeSectionSizes, CodeAlign); |
| RODataSize = computeAllocationSizeForSections(ROSectionSizes, RODataAlign); |
| RWDataSize = computeAllocationSizeForSections(RWSectionSizes, RWDataAlign); |
| |
| return Error::success(); |
| } |
| |
| // compute GOT size |
| unsigned RuntimeDyldImpl::computeGOTSize(const ObjectFile &Obj) { |
| size_t GotEntrySize = getGOTEntrySize(); |
| if (!GotEntrySize) |
| return 0; |
| |
| size_t GotSize = 0; |
| for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); |
| SI != SE; ++SI) { |
| |
| for (const RelocationRef &Reloc : SI->relocations()) |
| if (relocationNeedsGot(Reloc)) |
| GotSize += GotEntrySize; |
| } |
| |
| return GotSize; |
| } |
| |
| // compute stub buffer size for the given section |
| unsigned RuntimeDyldImpl::computeSectionStubBufSize(const ObjectFile &Obj, |
| const SectionRef &Section) { |
| unsigned StubSize = getMaxStubSize(); |
| if (StubSize == 0) { |
| return 0; |
| } |
| // FIXME: this is an inefficient way to handle this. We should computed the |
| // necessary section allocation size in loadObject by walking all the sections |
| // once. |
| unsigned StubBufSize = 0; |
| for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); |
| SI != SE; ++SI) { |
| section_iterator RelSecI = SI->getRelocatedSection(); |
| if (!(RelSecI == Section)) |
| continue; |
| |
| for (const RelocationRef &Reloc : SI->relocations()) |
| if (relocationNeedsStub(Reloc)) |
| StubBufSize += StubSize; |
| } |
| |
| // Get section data size and alignment |
| uint64_t DataSize = Section.getSize(); |
| uint64_t Alignment64 = Section.getAlignment(); |
| |
| // Add stubbuf size alignment |
| unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL; |
| unsigned StubAlignment = getStubAlignment(); |
| unsigned EndAlignment = (DataSize | Alignment) & -(DataSize | Alignment); |
| if (StubAlignment > EndAlignment) |
| StubBufSize += StubAlignment - EndAlignment; |
| return StubBufSize; |
| } |
| |
| uint64_t RuntimeDyldImpl::readBytesUnaligned(uint8_t *Src, |
| unsigned Size) const { |
| uint64_t Result = 0; |
| if (IsTargetLittleEndian) { |
| Src += Size - 1; |
| while (Size--) |
| Result = (Result << 8) | *Src--; |
| } else |
| while (Size--) |
| Result = (Result << 8) | *Src++; |
| |
| return Result; |
| } |
| |
| void RuntimeDyldImpl::writeBytesUnaligned(uint64_t Value, uint8_t *Dst, |
| unsigned Size) const { |
| if (IsTargetLittleEndian) { |
| while (Size--) { |
| *Dst++ = Value & 0xFF; |
| Value >>= 8; |
| } |
| } else { |
| Dst += Size - 1; |
| while (Size--) { |
| *Dst-- = Value & 0xFF; |
| Value >>= 8; |
| } |
| } |
| } |
| |
| Error RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj, |
| CommonSymbolList &CommonSymbols) { |
| if (CommonSymbols.empty()) |
| return Error::success(); |
| |
| uint64_t CommonSize = 0; |
| uint32_t CommonAlign = CommonSymbols.begin()->getAlignment(); |
| CommonSymbolList SymbolsToAllocate; |
| |
| DEBUG(dbgs() << "Processing common symbols...\n"); |
| |
| for (const auto &Sym : CommonSymbols) { |
| StringRef Name; |
| if (auto NameOrErr = Sym.getName()) |
| Name = *NameOrErr; |
| else |
| return NameOrErr.takeError(); |
| |
| // Skip common symbols already elsewhere. |
| if (GlobalSymbolTable.count(Name)) { |
| DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name |
| << "'\n"); |
| continue; |
| } |
| |
| if (auto Sym = Resolver.findSymbolInLogicalDylib(Name)) { |
| if (!Sym.getFlags().isCommon()) { |
| DEBUG(dbgs() << "\tSkipping common symbol '" << Name |
| << "' in favor of stronger definition.\n"); |
| continue; |
| } |
| } |
| uint32_t Align = Sym.getAlignment(); |
| uint64_t Size = Sym.getCommonSize(); |
| |
| CommonSize = alignTo(CommonSize, Align) + Size; |
| |
| SymbolsToAllocate.push_back(Sym); |
| } |
| |
| // Allocate memory for the section |
| unsigned SectionID = Sections.size(); |
| uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, CommonAlign, SectionID, |
| "<common symbols>", false); |
| if (!Addr) |
| report_fatal_error("Unable to allocate memory for common symbols!"); |
| uint64_t Offset = 0; |
| Sections.push_back( |
| SectionEntry("<common symbols>", Addr, CommonSize, CommonSize, 0)); |
| memset(Addr, 0, CommonSize); |
| |
| DEBUG(dbgs() << "emitCommonSection SectionID: " << SectionID << " new addr: " |
| << format("%p", Addr) << " DataSize: " << CommonSize << "\n"); |
| |
| // Assign the address of each symbol |
| for (auto &Sym : SymbolsToAllocate) { |
| uint32_t Align = Sym.getAlignment(); |
| uint64_t Size = Sym.getCommonSize(); |
| StringRef Name; |
| if (auto NameOrErr = Sym.getName()) |
| Name = *NameOrErr; |
| else |
| return NameOrErr.takeError(); |
| if (Align) { |
| // This symbol has an alignment requirement. |
| uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align); |
| Addr += AlignOffset; |
| Offset += AlignOffset; |
| } |
| JITSymbolFlags JITSymFlags = JITSymbolFlags::fromObjectSymbol(Sym); |
| DEBUG(dbgs() << "Allocating common symbol " << Name << " address " |
| << format("%p", Addr) << "\n"); |
| GlobalSymbolTable[Name] = |
| SymbolTableEntry(SectionID, Offset, JITSymFlags); |
| Offset += Size; |
| Addr += Size; |
| } |
| |
| if (Checker) |
| Checker->registerSection(Obj.getFileName(), SectionID); |
| |
| return Error::success(); |
| } |
| |
| Expected<unsigned> |
| RuntimeDyldImpl::emitSection(const ObjectFile &Obj, |
| const SectionRef &Section, |
| bool IsCode) { |
| StringRef data; |
| uint64_t Alignment64 = Section.getAlignment(); |
| |
| unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL; |
| unsigned PaddingSize = 0; |
| unsigned StubBufSize = 0; |
| bool IsRequired = isRequiredForExecution(Section); |
| bool IsVirtual = Section.isVirtual(); |
| bool IsZeroInit = isZeroInit(Section); |
| bool IsReadOnly = isReadOnlyData(Section); |
| uint64_t DataSize = Section.getSize(); |
| |
| StringRef Name; |
| if (auto EC = Section.getName(Name)) |
| return errorCodeToError(EC); |
| |
| StubBufSize = computeSectionStubBufSize(Obj, Section); |
| |
| // The .eh_frame section (at least on Linux) needs an extra four bytes padded |
| // with zeroes added at the end. For MachO objects, this section has a |
| // slightly different name, so this won't have any effect for MachO objects. |
| if (Name == ".eh_frame") |
| PaddingSize = 4; |
| |
| uintptr_t Allocate; |
| unsigned SectionID = Sections.size(); |
| uint8_t *Addr; |
| const char *pData = nullptr; |
| |
| // If this section contains any bits (i.e. isn't a virtual or bss section), |
| // grab a reference to them. |
| if (!IsVirtual && !IsZeroInit) { |
| // In either case, set the location of the unrelocated section in memory, |
| // since we still process relocations for it even if we're not applying them. |
| if (auto EC = Section.getContents(data)) |
| return errorCodeToError(EC); |
| pData = data.data(); |
| } |
| |
| // Code section alignment needs to be at least as high as stub alignment or |
| // padding calculations may by incorrect when the section is remapped to a |
| // higher alignment. |
| if (IsCode) |
| Alignment = std::max(Alignment, getStubAlignment()); |
| |
| // Some sections, such as debug info, don't need to be loaded for execution. |
| // Process those only if explicitly requested. |
| if (IsRequired || ProcessAllSections) { |
| Allocate = DataSize + PaddingSize + StubBufSize; |
| if (!Allocate) |
| Allocate = 1; |
| Addr = IsCode ? MemMgr.allocateCodeSection(Allocate, Alignment, SectionID, |
| Name) |
| : MemMgr.allocateDataSection(Allocate, Alignment, SectionID, |
| Name, IsReadOnly); |
| if (!Addr) |
| report_fatal_error("Unable to allocate section memory!"); |
| |
| // Zero-initialize or copy the data from the image |
| if (IsZeroInit || IsVirtual) |
| memset(Addr, 0, DataSize); |
| else |
| memcpy(Addr, pData, DataSize); |
| |
| // Fill in any extra bytes we allocated for padding |
| if (PaddingSize != 0) { |
| memset(Addr + DataSize, 0, PaddingSize); |
| // Update the DataSize variable so that the stub offset is set correctly. |
| DataSize += PaddingSize; |
| } |
| |
| DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name |
| << " obj addr: " << format("%p", pData) |
| << " new addr: " << format("%p", Addr) |
| << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize |
| << " Allocate: " << Allocate << "\n"); |
| } else { |
| // Even if we didn't load the section, we need to record an entry for it |
| // to handle later processing (and by 'handle' I mean don't do anything |
| // with these sections). |
| Allocate = 0; |
| Addr = nullptr; |
| DEBUG(dbgs() << "emitSection SectionID: " << SectionID << " Name: " << Name |
| << " obj addr: " << format("%p", data.data()) << " new addr: 0" |
| << " DataSize: " << DataSize << " StubBufSize: " << StubBufSize |
| << " Allocate: " << Allocate << "\n"); |
| } |
| |
| Sections.push_back( |
| SectionEntry(Name, Addr, DataSize, Allocate, (uintptr_t)pData)); |
| |
| // Debug info sections are linked as if their load address was zero |
| if (!IsRequired) |
| Sections.back().setLoadAddress(0); |
| |
| if (Checker) |
| Checker->registerSection(Obj.getFileName(), SectionID); |
| |
| return SectionID; |
| } |
| |
| Expected<unsigned> |
| RuntimeDyldImpl::findOrEmitSection(const ObjectFile &Obj, |
| const SectionRef &Section, |
| bool IsCode, |
| ObjSectionToIDMap &LocalSections) { |
| |
| unsigned SectionID = 0; |
| ObjSectionToIDMap::iterator i = LocalSections.find(Section); |
| if (i != LocalSections.end()) |
| SectionID = i->second; |
| else { |
| if (auto SectionIDOrErr = emitSection(Obj, Section, IsCode)) |
| SectionID = *SectionIDOrErr; |
| else |
| return SectionIDOrErr.takeError(); |
| LocalSections[Section] = SectionID; |
| } |
| return SectionID; |
| } |
| |
| void RuntimeDyldImpl::addRelocationForSection(const RelocationEntry &RE, |
| unsigned SectionID) { |
| Relocations[SectionID].push_back(RE); |
| } |
| |
| void RuntimeDyldImpl::addRelocationForSymbol(const RelocationEntry &RE, |
| StringRef SymbolName) { |
| // Relocation by symbol. If the symbol is found in the global symbol table, |
| // create an appropriate section relocation. Otherwise, add it to |
| // ExternalSymbolRelocations. |
| RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(SymbolName); |
| if (Loc == GlobalSymbolTable.end()) { |
| ExternalSymbolRelocations[SymbolName].push_back(RE); |
| } else { |
| // Copy the RE since we want to modify its addend. |
| RelocationEntry RECopy = RE; |
| const auto &SymInfo = Loc->second; |
| RECopy.Addend += SymInfo.getOffset(); |
| Relocations[SymInfo.getSectionID()].push_back(RECopy); |
| } |
| } |
| |
| uint8_t *RuntimeDyldImpl::createStubFunction(uint8_t *Addr, |
| unsigned AbiVariant) { |
| if (Arch == Triple::aarch64 || Arch == Triple::aarch64_be) { |
| // This stub has to be able to access the full address space, |
| // since symbol lookup won't necessarily find a handy, in-range, |
| // PLT stub for functions which could be anywhere. |
| // Stub can use ip0 (== x16) to calculate address |
| writeBytesUnaligned(0xd2e00010, Addr, 4); // movz ip0, #:abs_g3:<addr> |
| writeBytesUnaligned(0xf2c00010, Addr+4, 4); // movk ip0, #:abs_g2_nc:<addr> |
| writeBytesUnaligned(0xf2a00010, Addr+8, 4); // movk ip0, #:abs_g1_nc:<addr> |
| writeBytesUnaligned(0xf2800010, Addr+12, 4); // movk ip0, #:abs_g0_nc:<addr> |
| writeBytesUnaligned(0xd61f0200, Addr+16, 4); // br ip0 |
| |
| return Addr; |
| } else if (Arch == Triple::arm || Arch == Triple::armeb) { |
| // TODO: There is only ARM far stub now. We should add the Thumb stub, |
| // and stubs for branches Thumb - ARM and ARM - Thumb. |
| writeBytesUnaligned(0xe51ff004, Addr, 4); // ldr pc,<label> |
| return Addr + 4; |
| } else if (IsMipsO32ABI) { |
| // 0: 3c190000 lui t9,%hi(addr). |
| // 4: 27390000 addiu t9,t9,%lo(addr). |
| // 8: 03200008 jr t9. |
| // c: 00000000 nop. |
| const unsigned LuiT9Instr = 0x3c190000, AdduiT9Instr = 0x27390000; |
| const unsigned NopInstr = 0x0; |
| unsigned JrT9Instr = 0x03200008; |
| if ((AbiVariant & ELF::EF_MIPS_ARCH) == ELF::EF_MIPS_ARCH_32R6) |
| JrT9Instr = 0x03200009; |
| |
| writeBytesUnaligned(LuiT9Instr, Addr, 4); |
| writeBytesUnaligned(AdduiT9Instr, Addr+4, 4); |
| writeBytesUnaligned(JrT9Instr, Addr+8, 4); |
| writeBytesUnaligned(NopInstr, Addr+12, 4); |
| return Addr; |
| } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { |
| // Depending on which version of the ELF ABI is in use, we need to |
| // generate one of two variants of the stub. They both start with |
| // the same sequence to load the target address into r12. |
| writeInt32BE(Addr, 0x3D800000); // lis r12, highest(addr) |
| writeInt32BE(Addr+4, 0x618C0000); // ori r12, higher(addr) |
| writeInt32BE(Addr+8, 0x798C07C6); // sldi r12, r12, 32 |
| writeInt32BE(Addr+12, 0x658C0000); // oris r12, r12, h(addr) |
| writeInt32BE(Addr+16, 0x618C0000); // ori r12, r12, l(addr) |
| if (AbiVariant == 2) { |
| // PowerPC64 stub ELFv2 ABI: The address points to the function itself. |
| // The address is already in r12 as required by the ABI. Branch to it. |
| writeInt32BE(Addr+20, 0xF8410018); // std r2, 24(r1) |
| writeInt32BE(Addr+24, 0x7D8903A6); // mtctr r12 |
| writeInt32BE(Addr+28, 0x4E800420); // bctr |
| } else { |
| // PowerPC64 stub ELFv1 ABI: The address points to a function descriptor. |
| // Load the function address on r11 and sets it to control register. Also |
| // loads the function TOC in r2 and environment pointer to r11. |
| writeInt32BE(Addr+20, 0xF8410028); // std r2, 40(r1) |
| writeInt32BE(Addr+24, 0xE96C0000); // ld r11, 0(r12) |
| writeInt32BE(Addr+28, 0xE84C0008); // ld r2, 0(r12) |
| writeInt32BE(Addr+32, 0x7D6903A6); // mtctr r11 |
| writeInt32BE(Addr+36, 0xE96C0010); // ld r11, 16(r2) |
| writeInt32BE(Addr+40, 0x4E800420); // bctr |
| } |
| return Addr; |
| } else if (Arch == Triple::systemz) { |
| writeInt16BE(Addr, 0xC418); // lgrl %r1,.+8 |
| writeInt16BE(Addr+2, 0x0000); |
| writeInt16BE(Addr+4, 0x0004); |
| writeInt16BE(Addr+6, 0x07F1); // brc 15,%r1 |
| // 8-byte address stored at Addr + 8 |
| return Addr; |
| } else if (Arch == Triple::x86_64) { |
| *Addr = 0xFF; // jmp |
| *(Addr+1) = 0x25; // rip |
| // 32-bit PC-relative address of the GOT entry will be stored at Addr+2 |
| } else if (Arch == Triple::x86) { |
| *Addr = 0xE9; // 32-bit pc-relative jump. |
| } |
| return Addr; |
| } |
| |
| // Assign an address to a symbol name and resolve all the relocations |
| // associated with it. |
| void RuntimeDyldImpl::reassignSectionAddress(unsigned SectionID, |
| uint64_t Addr) { |
| // The address to use for relocation resolution is not |
| // the address of the local section buffer. We must be doing |
| // a remote execution environment of some sort. Relocations can't |
| // be applied until all the sections have been moved. The client must |
| // trigger this with a call to MCJIT::finalize() or |
| // RuntimeDyld::resolveRelocations(). |
| // |
| // Addr is a uint64_t because we can't assume the pointer width |
| // of the target is the same as that of the host. Just use a generic |
| // "big enough" type. |
| DEBUG(dbgs() << "Reassigning address for section " << SectionID << " (" |
| << Sections[SectionID].getName() << "): " |
| << format("0x%016" PRIx64, Sections[SectionID].getLoadAddress()) |
| << " -> " << format("0x%016" PRIx64, Addr) << "\n"); |
| Sections[SectionID].setLoadAddress(Addr); |
| } |
| |
| void RuntimeDyldImpl::resolveRelocationList(const RelocationList &Relocs, |
| uint64_t Value) { |
| for (unsigned i = 0, e = Relocs.size(); i != e; ++i) { |
| const RelocationEntry &RE = Relocs[i]; |
| // Ignore relocations for sections that were not loaded |
| if (Sections[RE.SectionID].getAddress() == nullptr) |
| continue; |
| resolveRelocation(RE, Value); |
| } |
| } |
| |
| void RuntimeDyldImpl::resolveExternalSymbols() { |
| while (!ExternalSymbolRelocations.empty()) { |
| StringMap<RelocationList>::iterator i = ExternalSymbolRelocations.begin(); |
| |
| StringRef Name = i->first(); |
| if (Name.size() == 0) { |
| // This is an absolute symbol, use an address of zero. |
| DEBUG(dbgs() << "Resolving absolute relocations." |
| << "\n"); |
| RelocationList &Relocs = i->second; |
| resolveRelocationList(Relocs, 0); |
| } else { |
| uint64_t Addr = 0; |
| RTDyldSymbolTable::const_iterator Loc = GlobalSymbolTable.find(Name); |
| if (Loc == GlobalSymbolTable.end()) { |
| // This is an external symbol, try to get its address from the symbol |
| // resolver. |
| // First search for the symbol in this logical dylib. |
| Addr = Resolver.findSymbolInLogicalDylib(Name.data()).getAddress(); |
| // If that fails, try searching for an external symbol. |
| if (!Addr) |
| Addr = Resolver.findSymbol(Name.data()).getAddress(); |
| // The call to getSymbolAddress may have caused additional modules to |
| // be loaded, which may have added new entries to the |
| // ExternalSymbolRelocations map. Consquently, we need to update our |
| // iterator. This is also why retrieval of the relocation list |
| // associated with this symbol is deferred until below this point. |
| // New entries may have been added to the relocation list. |
| i = ExternalSymbolRelocations.find(Name); |
| } else { |
| // We found the symbol in our global table. It was probably in a |
| // Module that we loaded previously. |
| const auto &SymInfo = Loc->second; |
| Addr = getSectionLoadAddress(SymInfo.getSectionID()) + |
| SymInfo.getOffset(); |
| } |
| |
| // FIXME: Implement error handling that doesn't kill the host program! |
| if (!Addr) |
| report_fatal_error("Program used external function '" + Name + |
| "' which could not be resolved!"); |
| |
| // If Resolver returned UINT64_MAX, the client wants to handle this symbol |
| // manually and we shouldn't resolve its relocations. |
| if (Addr != UINT64_MAX) { |
| DEBUG(dbgs() << "Resolving relocations Name: " << Name << "\t" |
| << format("0x%lx", Addr) << "\n"); |
| // This list may have been updated when we called getSymbolAddress, so |
| // don't change this code to get the list earlier. |
| RelocationList &Relocs = i->second; |
| resolveRelocationList(Relocs, Addr); |
| } |
| } |
| |
| ExternalSymbolRelocations.erase(i); |
| } |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // RuntimeDyld class implementation |
| |
| uint64_t RuntimeDyld::LoadedObjectInfo::getSectionLoadAddress( |
| const object::SectionRef &Sec) const { |
| |
| auto I = ObjSecToIDMap.find(Sec); |
| if (I != ObjSecToIDMap.end()) |
| return RTDyld.Sections[I->second].getLoadAddress(); |
| |
| return 0; |
| } |
| |
| void RuntimeDyld::MemoryManager::anchor() {} |
| void JITSymbolResolver::anchor() {} |
| |
| RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr, |
| JITSymbolResolver &Resolver) |
| : MemMgr(MemMgr), Resolver(Resolver) { |
| // FIXME: There's a potential issue lurking here if a single instance of |
| // RuntimeDyld is used to load multiple objects. The current implementation |
| // associates a single memory manager with a RuntimeDyld instance. Even |
| // though the public class spawns a new 'impl' instance for each load, |
| // they share a single memory manager. This can become a problem when page |
| // permissions are applied. |
| Dyld = nullptr; |
| ProcessAllSections = false; |
| Checker = nullptr; |
| } |
| |
| RuntimeDyld::~RuntimeDyld() {} |
| |
| static std::unique_ptr<RuntimeDyldCOFF> |
| createRuntimeDyldCOFF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM, |
| JITSymbolResolver &Resolver, bool ProcessAllSections, |
| RuntimeDyldCheckerImpl *Checker) { |
| std::unique_ptr<RuntimeDyldCOFF> Dyld = |
| RuntimeDyldCOFF::create(Arch, MM, Resolver); |
| Dyld->setProcessAllSections(ProcessAllSections); |
| Dyld->setRuntimeDyldChecker(Checker); |
| return Dyld; |
| } |
| |
| static std::unique_ptr<RuntimeDyldELF> |
| createRuntimeDyldELF(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM, |
| JITSymbolResolver &Resolver, bool ProcessAllSections, |
| RuntimeDyldCheckerImpl *Checker) { |
| std::unique_ptr<RuntimeDyldELF> Dyld = |
| RuntimeDyldELF::create(Arch, MM, Resolver); |
| Dyld->setProcessAllSections(ProcessAllSections); |
| Dyld->setRuntimeDyldChecker(Checker); |
| return Dyld; |
| } |
| |
| static std::unique_ptr<RuntimeDyldMachO> |
| createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM, |
| JITSymbolResolver &Resolver, |
| bool ProcessAllSections, |
| RuntimeDyldCheckerImpl *Checker) { |
| std::unique_ptr<RuntimeDyldMachO> Dyld = |
| RuntimeDyldMachO::create(Arch, MM, Resolver); |
| Dyld->setProcessAllSections(ProcessAllSections); |
| Dyld->setRuntimeDyldChecker(Checker); |
| return Dyld; |
| } |
| |
| std::unique_ptr<RuntimeDyld::LoadedObjectInfo> |
| RuntimeDyld::loadObject(const ObjectFile &Obj) { |
| if (!Dyld) { |
| if (Obj.isELF()) |
| Dyld = |
| createRuntimeDyldELF(static_cast<Triple::ArchType>(Obj.getArch()), |
| MemMgr, Resolver, ProcessAllSections, Checker); |
| else if (Obj.isMachO()) |
| Dyld = createRuntimeDyldMachO( |
| static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver, |
| ProcessAllSections, Checker); |
| else if (Obj.isCOFF()) |
| Dyld = createRuntimeDyldCOFF( |
| static_cast<Triple::ArchType>(Obj.getArch()), MemMgr, Resolver, |
| ProcessAllSections, Checker); |
| else |
| report_fatal_error("Incompatible object format!"); |
| } |
| |
| if (!Dyld->isCompatibleFile(Obj)) |
| report_fatal_error("Incompatible object format!"); |
| |
| auto LoadedObjInfo = Dyld->loadObject(Obj); |
| MemMgr.notifyObjectLoaded(*this, Obj); |
| return LoadedObjInfo; |
| } |
| |
| void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const { |
| if (!Dyld) |
| return nullptr; |
| return Dyld->getSymbolLocalAddress(Name); |
| } |
| |
| JITEvaluatedSymbol RuntimeDyld::getSymbol(StringRef Name) const { |
| if (!Dyld) |
| return nullptr; |
| return Dyld->getSymbol(Name); |
| } |
| |
| void RuntimeDyld::resolveRelocations() { Dyld->resolveRelocations(); } |
| |
| void RuntimeDyld::reassignSectionAddress(unsigned SectionID, uint64_t Addr) { |
| Dyld->reassignSectionAddress(SectionID, Addr); |
| } |
| |
| void RuntimeDyld::mapSectionAddress(const void *LocalAddress, |
| uint64_t TargetAddress) { |
| Dyld->mapSectionAddress(LocalAddress, TargetAddress); |
| } |
| |
| bool RuntimeDyld::hasError() { return Dyld->hasError(); } |
| |
| StringRef RuntimeDyld::getErrorString() { return Dyld->getErrorString(); } |
| |
| void RuntimeDyld::finalizeWithMemoryManagerLocking() { |
| bool MemoryFinalizationLocked = MemMgr.FinalizationLocked; |
| MemMgr.FinalizationLocked = true; |
| resolveRelocations(); |
| registerEHFrames(); |
| if (!MemoryFinalizationLocked) { |
| MemMgr.finalizeMemory(); |
| MemMgr.FinalizationLocked = false; |
| } |
| } |
| |
| void RuntimeDyld::registerEHFrames() { |
| if (Dyld) |
| Dyld->registerEHFrames(); |
| } |
| |
| void RuntimeDyld::deregisterEHFrames() { |
| if (Dyld) |
| Dyld->deregisterEHFrames(); |
| } |
| |
| } // end namespace llvm |