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Diffstat (limited to 'contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp')
| -rw-r--r-- | contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp | 953 |
1 files changed, 953 insertions, 0 deletions
diff --git a/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp b/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp new file mode 100644 index 0000000..fa50182 --- /dev/null +++ b/contrib/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyld.cpp @@ -0,0 +1,953 @@ +//===-- 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 "RuntimeDyldCheckerImpl.h" +#include "RuntimeDyldCOFF.h" +#include "RuntimeDyldELF.h" +#include "RuntimeDyldImpl.h" +#include "RuntimeDyldMachO.h" +#include "llvm/Object/ELFObjectFile.h" +#include "llvm/Object/COFF.h" +#include "llvm/Support/MathExtras.h" +#include "llvm/Support/MutexGuard.h" + +using namespace llvm; +using namespace llvm::object; + +#define DEBUG_TYPE "dyld" + +// 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() {} + +#ifndef NDEBUG +static void dumpSectionMemory(const SectionEntry &S, StringRef State) { + dbgs() << "----- Contents of section " << S.Name << " " << State << " -----"; + + if (S.Address == nullptr) { + dbgs() << "\n <section not emitted>\n"; + return; + } + + const unsigned ColsPerRow = 16; + + uint8_t *DataAddr = S.Address; + uint64_t LoadAddr = S.LoadAddress; + + unsigned StartPadding = LoadAddr & (ColsPerRow - 1); + unsigned BytesRemaining = S.Size; + + 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); + + // First, resolve relocations associated with external symbols. + resolveExternalSymbols(); + + // Just iterate over the sections we have and resolve all the relocations + // in them. Gross overkill, but it gets the job done. + for (int i = 0, e = Sections.size(); i != e; ++i) { + // 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. + uint64_t Addr = Sections[i].LoadAddress; + DEBUG(dbgs() << "Resolving relocations Section #" << i << "\t" + << format("%p", (uintptr_t)Addr) << "\n"); + DEBUG(dumpSectionMemory(Sections[i], "before relocations")); + resolveRelocationList(Relocations[i], Addr); + DEBUG(dumpSectionMemory(Sections[i], "after relocations")); + Relocations.erase(i); + } +} + +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].Address == LocalAddress) { + reassignSectionAddress(i, TargetAddress); + return; + } + } + llvm_unreachable("Attempting to remap address of unknown section!"); +} + +static std::error_code getOffset(const SymbolRef &Sym, uint64_t &Result) { + uint64_t Address; + if (std::error_code EC = Sym.getAddress(Address)) + return EC; + + if (Address == UnknownAddress) { + Result = UnknownAddress; + return std::error_code(); + } + + const ObjectFile *Obj = Sym.getObject(); + section_iterator SecI(Obj->section_begin()); + if (std::error_code EC = Sym.getSection(SecI)) + return EC; + + if (SecI == Obj->section_end()) { + Result = UnknownAddress; + return std::error_code(); + } + + uint64_t SectionAddress = SecI->getAddress(); + Result = Address - SectionAddress; + return std::error_code(); +} + +std::pair<unsigned, unsigned> +RuntimeDyldImpl::loadObjectImpl(const object::ObjectFile &Obj) { + MutexGuard locked(lock); + + // Grab the first Section ID. We'll use this later to construct the underlying + // range for the returned LoadedObjectInfo. + unsigned SectionsAddedBeginIdx = Sections.size(); + + // 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, DataSizeRO = 0, DataSizeRW = 0; + computeTotalAllocSize(Obj, CodeSize, DataSizeRO, DataSizeRW); + MemMgr.reserveAllocationSpace(CodeSize, DataSizeRO, DataSizeRW); + } + + // 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(); + + bool IsCommon = Flags & SymbolRef::SF_Common; + if (IsCommon) + CommonSymbols.push_back(*I); + else { + object::SymbolRef::Type SymType = I->getType(); + + if (SymType == object::SymbolRef::ST_Function || + SymType == object::SymbolRef::ST_Data || + SymType == object::SymbolRef::ST_Unknown) { + + ErrorOr<StringRef> NameOrErr = I->getName(); + Check(NameOrErr.getError()); + StringRef Name = *NameOrErr; + uint64_t SectOffset; + Check(getOffset(*I, SectOffset)); + section_iterator SI = Obj.section_end(); + Check(I->getSection(SI)); + if (SI == Obj.section_end()) + continue; + StringRef SectionData; + Check(SI->getContents(SectionData)); + bool IsCode = SI->isText(); + unsigned SectionID = + findOrEmitSection(Obj, *SI, IsCode, LocalSections); + DEBUG(dbgs() << "\tType: " << SymType << " Name: " << Name + << " SID: " << SectionID << " Offset: " + << format("%p", (uintptr_t)SectOffset) + << " flags: " << Flags << "\n"); + JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None; + if (Flags & SymbolRef::SF_Weak) + RTDyldSymFlags |= JITSymbolFlags::Weak; + if (Flags & SymbolRef::SF_Exported) + RTDyldSymFlags |= JITSymbolFlags::Exported; + GlobalSymbolTable[Name] = + SymbolTableEntry(SectionID, SectOffset, RTDyldSymFlags); + } + } + } + + // Allocate common symbols + emitCommonSymbols(Obj, CommonSymbols); + + // Parse and process relocations + DEBUG(dbgs() << "Parse relocations:\n"); + for (section_iterator SI = Obj.section_begin(), SE = Obj.section_end(); + SI != SE; ++SI) { + unsigned SectionID = 0; + 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(); + SectionID = + findOrEmitSection(Obj, *RelocatedSection, IsCode, LocalSections); + DEBUG(dbgs() << "\tSectionID: " << SectionID << "\n"); + + for (; I != E;) + I = processRelocationRef(SectionID, I, Obj, LocalSections, Stubs); + + // 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. + finalizeLoad(Obj, LocalSections); + + unsigned SectionsAddedEndIdx = Sections.size(); + + return std::make_pair(SectionsAddedBeginIdx, SectionsAddedEndIdx); +} + +// 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 +void RuntimeDyldImpl::computeTotalAllocSize(const ObjectFile &Obj, + uint64_t &CodeSize, + uint64_t &DataSizeRO, + uint64_t &DataSizeRW) { + // Compute the size of all sections required for execution + std::vector<uint64_t> CodeSectionSizes; + std::vector<uint64_t> ROSectionSizes; + std::vector<uint64_t> RWSectionSizes; + uint64_t MaxAlignment = sizeof(void *); + + // 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); + + // Consider only the sections that are required to be loaded for execution + if (IsRequired) { + StringRef Name; + uint64_t DataSize = Section.getSize(); + uint64_t Alignment64 = Section.getAlignment(); + bool IsCode = Section.isText(); + bool IsReadOnly = isReadOnlyData(Section); + Check(Section.getName(Name)); + unsigned Alignment = (unsigned)Alignment64 & 0xffffffffL; + + 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) { + CodeSectionSizes.push_back(SectionSize); + } else if (IsReadOnly) { + ROSectionSizes.push_back(SectionSize); + } else { + RWSectionSizes.push_back(SectionSize); + } + + // update the max alignment + if (Alignment > MaxAlignment) { + MaxAlignment = Alignment; + } + } + } + + // Compute the size of all common symbols + uint64_t CommonSize = 0; + 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(); + CommonSize += Size; + } + } + if (CommonSize != 0) { + RWSectionSizes.push_back(CommonSize); + } + + // 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, MaxAlignment); + DataSizeRO = computeAllocationSizeForSections(ROSectionSizes, MaxAlignment); + DataSizeRW = computeAllocationSizeForSections(RWSectionSizes, MaxAlignment); +} + +// 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()) { + (void)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; + } + } +} + +void RuntimeDyldImpl::emitCommonSymbols(const ObjectFile &Obj, + CommonSymbolList &CommonSymbols) { + if (CommonSymbols.empty()) + return; + + uint64_t CommonSize = 0; + CommonSymbolList SymbolsToAllocate; + + DEBUG(dbgs() << "Processing common symbols...\n"); + + for (const auto &Sym : CommonSymbols) { + ErrorOr<StringRef> NameOrErr = Sym.getName(); + Check(NameOrErr.getError()); + StringRef Name = *NameOrErr; + + // Skip common symbols already elsewhere. + if (GlobalSymbolTable.count(Name) || + Resolver.findSymbolInLogicalDylib(Name)) { + DEBUG(dbgs() << "\tSkipping already emitted common symbol '" << Name + << "'\n"); + continue; + } + + uint32_t Align = Sym.getAlignment(); + uint64_t Size = Sym.getCommonSize(); + + CommonSize += Align + Size; + SymbolsToAllocate.push_back(Sym); + } + + // Allocate memory for the section + unsigned SectionID = Sections.size(); + uint8_t *Addr = MemMgr.allocateDataSection(CommonSize, sizeof(void *), + SectionID, StringRef(), 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, 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(); + ErrorOr<StringRef> NameOrErr = Sym.getName(); + Check(NameOrErr.getError()); + StringRef Name = *NameOrErr; + if (Align) { + // This symbol has an alignment requirement. + uint64_t AlignOffset = OffsetToAlignment((uint64_t)Addr, Align); + Addr += AlignOffset; + Offset += AlignOffset; + } + uint32_t Flags = Sym.getFlags(); + JITSymbolFlags RTDyldSymFlags = JITSymbolFlags::None; + if (Flags & SymbolRef::SF_Weak) + RTDyldSymFlags |= JITSymbolFlags::Weak; + if (Flags & SymbolRef::SF_Exported) + RTDyldSymFlags |= JITSymbolFlags::Exported; + DEBUG(dbgs() << "Allocating common symbol " << Name << " address " + << format("%p", Addr) << "\n"); + GlobalSymbolTable[Name] = + SymbolTableEntry(SectionID, Offset, RTDyldSymFlags); + Offset += Size; + Addr += Size; + } +} + +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; + StringRef Name; + bool IsRequired = isRequiredForExecution(Section); + bool IsVirtual = Section.isVirtual(); + bool IsZeroInit = isZeroInit(Section); + bool IsReadOnly = isReadOnlyData(Section); + uint64_t DataSize = Section.getSize(); + Check(Section.getName(Name)); + + 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; + + // 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. + Check(Section.getContents(data)); + // Virtual sections have no data in the object image, so leave pData = 0 + if (!IsVirtual) + pData = data.data(); + + // Some sections, such as debug info, don't need to be loaded for execution. + // Leave those where they are. + if (IsRequired) { + 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, (uintptr_t)pData)); + + if (Checker) + Checker->registerSection(Obj.getFileName(), SectionID); + + return SectionID; +} + +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 { + SectionID = emitSection(Obj, Section, IsCode); + 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 JrT9Instr = 0x03200008, NopInstr = 0x0; + + 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].Name << "): " + << format("0x%016" PRIx64, Sections[SectionID].LoadAddress) << " -> " + << format("0x%016" PRIx64, Addr) << "\n"); + Sections[SectionID].LoadAddress = 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].Address == 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. + 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!"); + + 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( + StringRef SectionName) const { + for (unsigned I = BeginIdx; I != EndIdx; ++I) + if (RTDyld.Sections[I].Name == SectionName) + return RTDyld.Sections[I].LoadAddress; + + return 0; +} + +void RuntimeDyld::MemoryManager::anchor() {} +void RuntimeDyld::SymbolResolver::anchor() {} + +RuntimeDyld::RuntimeDyld(RuntimeDyld::MemoryManager &MemMgr, + RuntimeDyld::SymbolResolver &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, + RuntimeDyld::SymbolResolver &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(RuntimeDyld::MemoryManager &MM, + RuntimeDyld::SymbolResolver &Resolver, + bool ProcessAllSections, RuntimeDyldCheckerImpl *Checker) { + std::unique_ptr<RuntimeDyldELF> Dyld(new RuntimeDyldELF(MM, Resolver)); + Dyld->setProcessAllSections(ProcessAllSections); + Dyld->setRuntimeDyldChecker(Checker); + return Dyld; +} + +static std::unique_ptr<RuntimeDyldMachO> +createRuntimeDyldMachO(Triple::ArchType Arch, RuntimeDyld::MemoryManager &MM, + RuntimeDyld::SymbolResolver &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(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!"); + + return Dyld->loadObject(Obj); +} + +void *RuntimeDyld::getSymbolLocalAddress(StringRef Name) const { + if (!Dyld) + return nullptr; + return Dyld->getSymbolLocalAddress(Name); +} + +RuntimeDyld::SymbolInfo 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::registerEHFrames() { + if (Dyld) + Dyld->registerEHFrames(); +} + +void RuntimeDyld::deregisterEHFrames() { + if (Dyld) + Dyld->deregisterEHFrames(); +} + +} // end namespace llvm |
