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Diffstat (limited to 'llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h')
| -rw-r--r-- | llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h | 586 |
1 files changed, 586 insertions, 0 deletions
diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h new file mode 100644 index 000000000000..cec7b92b8c48 --- /dev/null +++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RuntimeDyldImpl.h @@ -0,0 +1,586 @@ +//===-- RuntimeDyldImpl.h - Run-time dynamic linker for MC-JIT --*- C++ -*-===// +// +// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. +// See https://llvm.org/LICENSE.txt for license information. +// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception +// +//===----------------------------------------------------------------------===// +// +// Interface for the implementations of runtime dynamic linker facilities. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDIMPL_H +#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDIMPL_H + +#include "llvm/ADT/SmallVector.h" +#include "llvm/ADT/StringMap.h" +#include "llvm/ADT/Triple.h" +#include "llvm/ExecutionEngine/RTDyldMemoryManager.h" +#include "llvm/ExecutionEngine/RuntimeDyld.h" +#include "llvm/ExecutionEngine/RuntimeDyldChecker.h" +#include "llvm/Object/ObjectFile.h" +#include "llvm/Support/Debug.h" +#include "llvm/Support/ErrorHandling.h" +#include "llvm/Support/Format.h" +#include "llvm/Support/Host.h" +#include "llvm/Support/Mutex.h" +#include "llvm/Support/SwapByteOrder.h" +#include <map> +#include <system_error> +#include <unordered_map> + +using namespace llvm; +using namespace llvm::object; + +namespace llvm { + +class Twine; + +#define UNIMPLEMENTED_RELOC(RelType) \ + case RelType: \ + return make_error<RuntimeDyldError>("Unimplemented relocation: " #RelType) + +/// SectionEntry - represents a section emitted into memory by the dynamic +/// linker. +class SectionEntry { + /// Name - section name. + std::string Name; + + /// Address - address in the linker's memory where the section resides. + uint8_t *Address; + + /// Size - section size. Doesn't include the stubs. + size_t Size; + + /// LoadAddress - the address of the section in the target process's memory. + /// Used for situations in which JIT-ed code is being executed in the address + /// space of a separate process. If the code executes in the same address + /// space where it was JIT-ed, this just equals Address. + uint64_t LoadAddress; + + /// StubOffset - used for architectures with stub functions for far + /// relocations (like ARM). + uintptr_t StubOffset; + + /// The total amount of space allocated for this section. This includes the + /// section size and the maximum amount of space that the stubs can occupy. + size_t AllocationSize; + + /// ObjAddress - address of the section in the in-memory object file. Used + /// for calculating relocations in some object formats (like MachO). + uintptr_t ObjAddress; + +public: + SectionEntry(StringRef name, uint8_t *address, size_t size, + size_t allocationSize, uintptr_t objAddress) + : Name(name), Address(address), Size(size), + LoadAddress(reinterpret_cast<uintptr_t>(address)), StubOffset(size), + AllocationSize(allocationSize), ObjAddress(objAddress) { + // AllocationSize is used only in asserts, prevent an "unused private field" + // warning: + (void)AllocationSize; + } + + StringRef getName() const { return Name; } + + uint8_t *getAddress() const { return Address; } + + /// Return the address of this section with an offset. + uint8_t *getAddressWithOffset(unsigned OffsetBytes) const { + assert(OffsetBytes <= AllocationSize && "Offset out of bounds!"); + return Address + OffsetBytes; + } + + size_t getSize() const { return Size; } + + uint64_t getLoadAddress() const { return LoadAddress; } + void setLoadAddress(uint64_t LA) { LoadAddress = LA; } + + /// Return the load address of this section with an offset. + uint64_t getLoadAddressWithOffset(unsigned OffsetBytes) const { + assert(OffsetBytes <= AllocationSize && "Offset out of bounds!"); + return LoadAddress + OffsetBytes; + } + + uintptr_t getStubOffset() const { return StubOffset; } + + void advanceStubOffset(unsigned StubSize) { + StubOffset += StubSize; + assert(StubOffset <= AllocationSize && "Not enough space allocated!"); + } + + uintptr_t getObjAddress() const { return ObjAddress; } +}; + +/// RelocationEntry - used to represent relocations internally in the dynamic +/// linker. +class RelocationEntry { +public: + /// SectionID - the section this relocation points to. + unsigned SectionID; + + /// Offset - offset into the section. + uint64_t Offset; + + /// RelType - relocation type. + uint32_t RelType; + + /// Addend - the relocation addend encoded in the instruction itself. Also + /// used to make a relocation section relative instead of symbol relative. + int64_t Addend; + + struct SectionPair { + uint32_t SectionA; + uint32_t SectionB; + }; + + /// SymOffset - Section offset of the relocation entry's symbol (used for GOT + /// lookup). + union { + uint64_t SymOffset; + SectionPair Sections; + }; + + /// True if this is a PCRel relocation (MachO specific). + bool IsPCRel; + + /// The size of this relocation (MachO specific). + unsigned Size; + + // ARM (MachO and COFF) specific. + bool IsTargetThumbFunc = false; + + RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend) + : SectionID(id), Offset(offset), RelType(type), Addend(addend), + SymOffset(0), IsPCRel(false), Size(0), IsTargetThumbFunc(false) {} + + RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend, + uint64_t symoffset) + : SectionID(id), Offset(offset), RelType(type), Addend(addend), + SymOffset(symoffset), IsPCRel(false), Size(0), + IsTargetThumbFunc(false) {} + + RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend, + bool IsPCRel, unsigned Size) + : SectionID(id), Offset(offset), RelType(type), Addend(addend), + SymOffset(0), IsPCRel(IsPCRel), Size(Size), IsTargetThumbFunc(false) {} + + RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend, + unsigned SectionA, uint64_t SectionAOffset, unsigned SectionB, + uint64_t SectionBOffset, bool IsPCRel, unsigned Size) + : SectionID(id), Offset(offset), RelType(type), + Addend(SectionAOffset - SectionBOffset + addend), IsPCRel(IsPCRel), + Size(Size), IsTargetThumbFunc(false) { + Sections.SectionA = SectionA; + Sections.SectionB = SectionB; + } + + RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend, + unsigned SectionA, uint64_t SectionAOffset, unsigned SectionB, + uint64_t SectionBOffset, bool IsPCRel, unsigned Size, + bool IsTargetThumbFunc) + : SectionID(id), Offset(offset), RelType(type), + Addend(SectionAOffset - SectionBOffset + addend), IsPCRel(IsPCRel), + Size(Size), IsTargetThumbFunc(IsTargetThumbFunc) { + Sections.SectionA = SectionA; + Sections.SectionB = SectionB; + } +}; + +class RelocationValueRef { +public: + unsigned SectionID; + uint64_t Offset; + int64_t Addend; + const char *SymbolName; + bool IsStubThumb = false; + RelocationValueRef() : SectionID(0), Offset(0), Addend(0), + SymbolName(nullptr) {} + + inline bool operator==(const RelocationValueRef &Other) const { + return SectionID == Other.SectionID && Offset == Other.Offset && + Addend == Other.Addend && SymbolName == Other.SymbolName && + IsStubThumb == Other.IsStubThumb; + } + inline bool operator<(const RelocationValueRef &Other) const { + if (SectionID != Other.SectionID) + return SectionID < Other.SectionID; + if (Offset != Other.Offset) + return Offset < Other.Offset; + if (Addend != Other.Addend) + return Addend < Other.Addend; + if (IsStubThumb != Other.IsStubThumb) + return IsStubThumb < Other.IsStubThumb; + return SymbolName < Other.SymbolName; + } +}; + +/// Symbol info for RuntimeDyld. +class SymbolTableEntry { +public: + SymbolTableEntry() = default; + + SymbolTableEntry(unsigned SectionID, uint64_t Offset, JITSymbolFlags Flags) + : Offset(Offset), SectionID(SectionID), Flags(Flags) {} + + unsigned getSectionID() const { return SectionID; } + uint64_t getOffset() const { return Offset; } + void setOffset(uint64_t NewOffset) { Offset = NewOffset; } + + JITSymbolFlags getFlags() const { return Flags; } + +private: + uint64_t Offset = 0; + unsigned SectionID = 0; + JITSymbolFlags Flags = JITSymbolFlags::None; +}; + +typedef StringMap<SymbolTableEntry> RTDyldSymbolTable; + +class RuntimeDyldImpl { + friend class RuntimeDyld::LoadedObjectInfo; +protected: + static const unsigned AbsoluteSymbolSection = ~0U; + + // The MemoryManager to load objects into. + RuntimeDyld::MemoryManager &MemMgr; + + // The symbol resolver to use for external symbols. + JITSymbolResolver &Resolver; + + // A list of all sections emitted by the dynamic linker. These sections are + // referenced in the code by means of their index in this list - SectionID. + typedef SmallVector<SectionEntry, 64> SectionList; + SectionList Sections; + + typedef unsigned SID; // Type for SectionIDs +#define RTDYLD_INVALID_SECTION_ID ((RuntimeDyldImpl::SID)(-1)) + + // Keep a map of sections from object file to the SectionID which + // references it. + typedef std::map<SectionRef, unsigned> ObjSectionToIDMap; + + // A global symbol table for symbols from all loaded modules. + RTDyldSymbolTable GlobalSymbolTable; + + // Keep a map of common symbols to their info pairs + typedef std::vector<SymbolRef> CommonSymbolList; + + // For each symbol, keep a list of relocations based on it. Anytime + // its address is reassigned (the JIT re-compiled the function, e.g.), + // the relocations get re-resolved. + // The symbol (or section) the relocation is sourced from is the Key + // in the relocation list where it's stored. + typedef SmallVector<RelocationEntry, 64> RelocationList; + // Relocations to sections already loaded. Indexed by SectionID which is the + // source of the address. The target where the address will be written is + // SectionID/Offset in the relocation itself. + std::unordered_map<unsigned, RelocationList> Relocations; + + // Relocations to external symbols that are not yet resolved. Symbols are + // external when they aren't found in the global symbol table of all loaded + // modules. This map is indexed by symbol name. + StringMap<RelocationList> ExternalSymbolRelocations; + + + typedef std::map<RelocationValueRef, uintptr_t> StubMap; + + Triple::ArchType Arch; + bool IsTargetLittleEndian; + bool IsMipsO32ABI; + bool IsMipsN32ABI; + bool IsMipsN64ABI; + + // True if all sections should be passed to the memory manager, false if only + // sections containing relocations should be. Defaults to 'false'. + bool ProcessAllSections; + + // This mutex prevents simultaneously loading objects from two different + // threads. This keeps us from having to protect individual data structures + // and guarantees that section allocation requests to the memory manager + // won't be interleaved between modules. It is also used in mapSectionAddress + // and resolveRelocations to protect write access to internal data structures. + // + // loadObject may be called on the same thread during the handling of of + // processRelocations, and that's OK. The handling of the relocation lists + // is written in such a way as to work correctly if new elements are added to + // the end of the list while the list is being processed. + sys::Mutex lock; + + using NotifyStubEmittedFunction = + RuntimeDyld::NotifyStubEmittedFunction; + NotifyStubEmittedFunction NotifyStubEmitted; + + virtual unsigned getMaxStubSize() const = 0; + virtual unsigned getStubAlignment() = 0; + + bool HasError; + std::string ErrorStr; + + void writeInt16BE(uint8_t *Addr, uint16_t Value) { + if (IsTargetLittleEndian) + sys::swapByteOrder(Value); + *Addr = (Value >> 8) & 0xFF; + *(Addr + 1) = Value & 0xFF; + } + + void writeInt32BE(uint8_t *Addr, uint32_t Value) { + if (IsTargetLittleEndian) + sys::swapByteOrder(Value); + *Addr = (Value >> 24) & 0xFF; + *(Addr + 1) = (Value >> 16) & 0xFF; + *(Addr + 2) = (Value >> 8) & 0xFF; + *(Addr + 3) = Value & 0xFF; + } + + void writeInt64BE(uint8_t *Addr, uint64_t Value) { + if (IsTargetLittleEndian) + sys::swapByteOrder(Value); + *Addr = (Value >> 56) & 0xFF; + *(Addr + 1) = (Value >> 48) & 0xFF; + *(Addr + 2) = (Value >> 40) & 0xFF; + *(Addr + 3) = (Value >> 32) & 0xFF; + *(Addr + 4) = (Value >> 24) & 0xFF; + *(Addr + 5) = (Value >> 16) & 0xFF; + *(Addr + 6) = (Value >> 8) & 0xFF; + *(Addr + 7) = Value & 0xFF; + } + + virtual void setMipsABI(const ObjectFile &Obj) { + IsMipsO32ABI = false; + IsMipsN32ABI = false; + IsMipsN64ABI = false; + } + + /// Endian-aware read Read the least significant Size bytes from Src. + uint64_t readBytesUnaligned(uint8_t *Src, unsigned Size) const; + + /// Endian-aware write. Write the least significant Size bytes from Value to + /// Dst. + void writeBytesUnaligned(uint64_t Value, uint8_t *Dst, unsigned Size) const; + + /// Generate JITSymbolFlags from a libObject symbol. + virtual Expected<JITSymbolFlags> getJITSymbolFlags(const SymbolRef &Sym); + + /// Modify the given target address based on the given symbol flags. + /// This can be used by subclasses to tweak addresses based on symbol flags, + /// For example: the MachO/ARM target uses it to set the low bit if the target + /// is a thumb symbol. + virtual uint64_t modifyAddressBasedOnFlags(uint64_t Addr, + JITSymbolFlags Flags) const { + return Addr; + } + + /// Given the common symbols discovered in the object file, emit a + /// new section for them and update the symbol mappings in the object and + /// symbol table. + Error emitCommonSymbols(const ObjectFile &Obj, + CommonSymbolList &CommonSymbols, uint64_t CommonSize, + uint32_t CommonAlign); + + /// Emits section data from the object file to the MemoryManager. + /// \param IsCode if it's true then allocateCodeSection() will be + /// used for emits, else allocateDataSection() will be used. + /// \return SectionID. + Expected<unsigned> emitSection(const ObjectFile &Obj, + const SectionRef &Section, + bool IsCode); + + /// Find Section in LocalSections. If the secton is not found - emit + /// it and store in LocalSections. + /// \param IsCode if it's true then allocateCodeSection() will be + /// used for emmits, else allocateDataSection() will be used. + /// \return SectionID. + Expected<unsigned> findOrEmitSection(const ObjectFile &Obj, + const SectionRef &Section, bool IsCode, + ObjSectionToIDMap &LocalSections); + + // Add a relocation entry that uses the given section. + void addRelocationForSection(const RelocationEntry &RE, unsigned SectionID); + + // Add a relocation entry that uses the given symbol. This symbol may + // be found in the global symbol table, or it may be external. + void addRelocationForSymbol(const RelocationEntry &RE, StringRef SymbolName); + + /// Emits long jump instruction to Addr. + /// \return Pointer to the memory area for emitting target address. + uint8_t *createStubFunction(uint8_t *Addr, unsigned AbiVariant = 0); + + /// Resolves relocations from Relocs list with address from Value. + void resolveRelocationList(const RelocationList &Relocs, uint64_t Value); + + /// A object file specific relocation resolver + /// \param RE The relocation to be resolved + /// \param Value Target symbol address to apply the relocation action + virtual void resolveRelocation(const RelocationEntry &RE, uint64_t Value) = 0; + + /// Parses one or more object file relocations (some object files use + /// relocation pairs) and stores it to Relocations or SymbolRelocations + /// (this depends on the object file type). + /// \return Iterator to the next relocation that needs to be parsed. + virtual Expected<relocation_iterator> + processRelocationRef(unsigned SectionID, relocation_iterator RelI, + const ObjectFile &Obj, ObjSectionToIDMap &ObjSectionToID, + StubMap &Stubs) = 0; + + void applyExternalSymbolRelocations( + const StringMap<JITEvaluatedSymbol> ExternalSymbolMap); + + /// Resolve relocations to external symbols. + Error resolveExternalSymbols(); + + // Compute an upper bound of the memory that is required to load all + // sections + Error computeTotalAllocSize(const ObjectFile &Obj, + uint64_t &CodeSize, uint32_t &CodeAlign, + uint64_t &RODataSize, uint32_t &RODataAlign, + uint64_t &RWDataSize, uint32_t &RWDataAlign); + + // Compute GOT size + unsigned computeGOTSize(const ObjectFile &Obj); + + // Compute the stub buffer size required for a section + unsigned computeSectionStubBufSize(const ObjectFile &Obj, + const SectionRef &Section); + + // Implementation of the generic part of the loadObject algorithm. + Expected<ObjSectionToIDMap> loadObjectImpl(const object::ObjectFile &Obj); + + // Return size of Global Offset Table (GOT) entry + virtual size_t getGOTEntrySize() { return 0; } + + // Return true if the relocation R may require allocating a GOT entry. + virtual bool relocationNeedsGot(const RelocationRef &R) const { + return false; + } + + // Return true if the relocation R may require allocating a stub. + virtual bool relocationNeedsStub(const RelocationRef &R) const { + return true; // Conservative answer + } + +public: + RuntimeDyldImpl(RuntimeDyld::MemoryManager &MemMgr, + JITSymbolResolver &Resolver) + : MemMgr(MemMgr), Resolver(Resolver), + ProcessAllSections(false), HasError(false) { + } + + virtual ~RuntimeDyldImpl(); + + void setProcessAllSections(bool ProcessAllSections) { + this->ProcessAllSections = ProcessAllSections; + } + + virtual std::unique_ptr<RuntimeDyld::LoadedObjectInfo> + loadObject(const object::ObjectFile &Obj) = 0; + + uint64_t getSectionLoadAddress(unsigned SectionID) const { + return Sections[SectionID].getLoadAddress(); + } + + uint8_t *getSectionAddress(unsigned SectionID) const { + return Sections[SectionID].getAddress(); + } + + StringRef getSectionContent(unsigned SectionID) const { + return StringRef(reinterpret_cast<char *>(Sections[SectionID].getAddress()), + Sections[SectionID].getStubOffset() + getMaxStubSize()); + } + + uint8_t* getSymbolLocalAddress(StringRef Name) const { + // FIXME: Just look up as a function for now. Overly simple of course. + // Work in progress. + RTDyldSymbolTable::const_iterator pos = GlobalSymbolTable.find(Name); + if (pos == GlobalSymbolTable.end()) + return nullptr; + const auto &SymInfo = pos->second; + // Absolute symbols do not have a local address. + if (SymInfo.getSectionID() == AbsoluteSymbolSection) + return nullptr; + return getSectionAddress(SymInfo.getSectionID()) + SymInfo.getOffset(); + } + + unsigned getSymbolSectionID(StringRef Name) const { + auto GSTItr = GlobalSymbolTable.find(Name); + if (GSTItr == GlobalSymbolTable.end()) + return ~0U; + return GSTItr->second.getSectionID(); + } + + JITEvaluatedSymbol getSymbol(StringRef Name) const { + // FIXME: Just look up as a function for now. Overly simple of course. + // Work in progress. + RTDyldSymbolTable::const_iterator pos = GlobalSymbolTable.find(Name); + if (pos == GlobalSymbolTable.end()) + return nullptr; + const auto &SymEntry = pos->second; + uint64_t SectionAddr = 0; + if (SymEntry.getSectionID() != AbsoluteSymbolSection) + SectionAddr = getSectionLoadAddress(SymEntry.getSectionID()); + uint64_t TargetAddr = SectionAddr + SymEntry.getOffset(); + + // FIXME: Have getSymbol should return the actual address and the client + // modify it based on the flags. This will require clients to be + // aware of the target architecture, which we should build + // infrastructure for. + TargetAddr = modifyAddressBasedOnFlags(TargetAddr, SymEntry.getFlags()); + return JITEvaluatedSymbol(TargetAddr, SymEntry.getFlags()); + } + + std::map<StringRef, JITEvaluatedSymbol> getSymbolTable() const { + std::map<StringRef, JITEvaluatedSymbol> Result; + + for (auto &KV : GlobalSymbolTable) { + auto SectionID = KV.second.getSectionID(); + uint64_t SectionAddr = 0; + if (SectionID != AbsoluteSymbolSection) + SectionAddr = getSectionLoadAddress(SectionID); + Result[KV.first()] = + JITEvaluatedSymbol(SectionAddr + KV.second.getOffset(), KV.second.getFlags()); + } + + return Result; + } + + void resolveRelocations(); + + void resolveLocalRelocations(); + + static void finalizeAsync(std::unique_ptr<RuntimeDyldImpl> This, + unique_function<void(Error)> OnEmitted, + std::unique_ptr<MemoryBuffer> UnderlyingBuffer); + + void reassignSectionAddress(unsigned SectionID, uint64_t Addr); + + void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress); + + // Is the linker in an error state? + bool hasError() { return HasError; } + + // Mark the error condition as handled and continue. + void clearError() { HasError = false; } + + // Get the error message. + StringRef getErrorString() { return ErrorStr; } + + virtual bool isCompatibleFile(const ObjectFile &Obj) const = 0; + + void setNotifyStubEmitted(NotifyStubEmittedFunction NotifyStubEmitted) { + this->NotifyStubEmitted = std::move(NotifyStubEmitted); + } + + virtual void registerEHFrames(); + + void deregisterEHFrames(); + + virtual Error finalizeLoad(const ObjectFile &ObjImg, + ObjSectionToIDMap &SectionMap) { + return Error::success(); + } +}; + +} // end namespace llvm + +#endif |