forked from OSchip/llvm-project
451 lines
16 KiB
C++
451 lines
16 KiB
C++
//===-- RuntimeDyldImpl.h - Run-time dynamic linker for MC-JIT --*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Interface for the implementations of runtime dynamic linker facilities.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDIMPL_H
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#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_RUNTIMEDYLDIMPL_H
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#include "llvm/ADT/DenseMap.h"
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#include "llvm/ADT/SmallVector.h"
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#include "llvm/ADT/StringMap.h"
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#include "llvm/ADT/Triple.h"
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#include "llvm/ExecutionEngine/RuntimeDyld.h"
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#include "llvm/ExecutionEngine/RuntimeDyldChecker.h"
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#include "llvm/Object/ObjectFile.h"
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#include "llvm/Support/Debug.h"
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#include "llvm/Support/ErrorHandling.h"
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#include "llvm/Support/Format.h"
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#include "llvm/Support/Host.h"
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#include "llvm/Support/Mutex.h"
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#include "llvm/Support/SwapByteOrder.h"
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#include "llvm/Support/raw_ostream.h"
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#include <map>
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#include <system_error>
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using namespace llvm;
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using namespace llvm::object;
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namespace llvm {
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class Twine;
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/// SectionEntry - represents a section emitted into memory by the dynamic
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/// linker.
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class SectionEntry {
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public:
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/// Name - section name.
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StringRef Name;
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/// Address - address in the linker's memory where the section resides.
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uint8_t *Address;
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/// Size - section size. Doesn't include the stubs.
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size_t Size;
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/// LoadAddress - the address of the section in the target process's memory.
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/// Used for situations in which JIT-ed code is being executed in the address
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/// space of a separate process. If the code executes in the same address
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/// space where it was JIT-ed, this just equals Address.
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uint64_t LoadAddress;
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/// StubOffset - used for architectures with stub functions for far
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/// relocations (like ARM).
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uintptr_t StubOffset;
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/// ObjAddress - address of the section in the in-memory object file. Used
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/// for calculating relocations in some object formats (like MachO).
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uintptr_t ObjAddress;
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SectionEntry(StringRef name, uint8_t *address, size_t size,
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uintptr_t objAddress)
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: Name(name), Address(address), Size(size),
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LoadAddress(reinterpret_cast<uintptr_t>(address)), StubOffset(size),
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ObjAddress(objAddress) {}
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};
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/// RelocationEntry - used to represent relocations internally in the dynamic
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/// linker.
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class RelocationEntry {
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public:
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/// SectionID - the section this relocation points to.
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unsigned SectionID;
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/// Offset - offset into the section.
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uint64_t Offset;
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/// RelType - relocation type.
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uint32_t RelType;
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/// Addend - the relocation addend encoded in the instruction itself. Also
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/// used to make a relocation section relative instead of symbol relative.
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int64_t Addend;
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struct SectionPair {
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uint32_t SectionA;
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uint32_t SectionB;
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};
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/// SymOffset - Section offset of the relocation entry's symbol (used for GOT
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/// lookup).
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union {
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uint64_t SymOffset;
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SectionPair Sections;
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};
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/// True if this is a PCRel relocation (MachO specific).
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bool IsPCRel;
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/// The size of this relocation (MachO specific).
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unsigned Size;
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RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend)
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: SectionID(id), Offset(offset), RelType(type), Addend(addend),
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SymOffset(0), IsPCRel(false), Size(0) {}
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RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend,
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uint64_t symoffset)
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: SectionID(id), Offset(offset), RelType(type), Addend(addend),
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SymOffset(symoffset), IsPCRel(false), Size(0) {}
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RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend,
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bool IsPCRel, unsigned Size)
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: SectionID(id), Offset(offset), RelType(type), Addend(addend),
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SymOffset(0), IsPCRel(IsPCRel), Size(Size) {}
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RelocationEntry(unsigned id, uint64_t offset, uint32_t type, int64_t addend,
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unsigned SectionA, uint64_t SectionAOffset, unsigned SectionB,
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uint64_t SectionBOffset, bool IsPCRel, unsigned Size)
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: SectionID(id), Offset(offset), RelType(type),
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Addend(SectionAOffset - SectionBOffset + addend), IsPCRel(IsPCRel),
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Size(Size) {
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Sections.SectionA = SectionA;
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Sections.SectionB = SectionB;
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}
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};
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class RelocationValueRef {
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public:
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unsigned SectionID;
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uint64_t Offset;
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int64_t Addend;
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const char *SymbolName;
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RelocationValueRef() : SectionID(0), Offset(0), Addend(0),
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SymbolName(nullptr) {}
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inline bool operator==(const RelocationValueRef &Other) const {
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return SectionID == Other.SectionID && Offset == Other.Offset &&
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Addend == Other.Addend && SymbolName == Other.SymbolName;
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}
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inline bool operator<(const RelocationValueRef &Other) const {
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if (SectionID != Other.SectionID)
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return SectionID < Other.SectionID;
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if (Offset != Other.Offset)
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return Offset < Other.Offset;
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if (Addend != Other.Addend)
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return Addend < Other.Addend;
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return SymbolName < Other.SymbolName;
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}
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};
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/// @brief Symbol info for RuntimeDyld.
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class SymbolInfo {
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public:
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typedef enum { Hidden = 0, Default = 1 } Visibility;
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SymbolInfo() : Offset(0), SectionID(0), Vis(Hidden) {}
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SymbolInfo(unsigned SectionID, uint64_t Offset, Visibility Vis)
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: Offset(Offset), SectionID(SectionID), Vis(Vis) {}
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unsigned getSectionID() const { return SectionID; }
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uint64_t getOffset() const { return Offset; }
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Visibility getVisibility() const { return Vis; }
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private:
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uint64_t Offset;
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unsigned SectionID : 31;
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Visibility Vis : 1;
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};
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typedef StringMap<SymbolInfo> RTDyldSymbolTable;
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class RuntimeDyldImpl {
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friend class RuntimeDyld::LoadedObjectInfo;
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friend class RuntimeDyldCheckerImpl;
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protected:
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// The MemoryManager to load objects into.
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RTDyldMemoryManager *MemMgr;
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// Attached RuntimeDyldChecker instance. Null if no instance attached.
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RuntimeDyldCheckerImpl *Checker;
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// A list of all sections emitted by the dynamic linker. These sections are
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// referenced in the code by means of their index in this list - SectionID.
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typedef SmallVector<SectionEntry, 64> SectionList;
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SectionList Sections;
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typedef unsigned SID; // Type for SectionIDs
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#define RTDYLD_INVALID_SECTION_ID ((SID)(-1))
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// Keep a map of sections from object file to the SectionID which
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// references it.
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typedef std::map<SectionRef, unsigned> ObjSectionToIDMap;
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// A global symbol table for symbols from all loaded modules.
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RTDyldSymbolTable GlobalSymbolTable;
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// Pair representing the size and alignment requirement for a common symbol.
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typedef std::pair<unsigned, unsigned> CommonSymbolInfo;
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// Keep a map of common symbols to their info pairs
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typedef std::map<SymbolRef, CommonSymbolInfo> CommonSymbolMap;
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// For each symbol, keep a list of relocations based on it. Anytime
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// its address is reassigned (the JIT re-compiled the function, e.g.),
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// the relocations get re-resolved.
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// The symbol (or section) the relocation is sourced from is the Key
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// in the relocation list where it's stored.
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typedef SmallVector<RelocationEntry, 64> RelocationList;
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// Relocations to sections already loaded. Indexed by SectionID which is the
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// source of the address. The target where the address will be written is
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// SectionID/Offset in the relocation itself.
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DenseMap<unsigned, RelocationList> Relocations;
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// Relocations to external symbols that are not yet resolved. Symbols are
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// external when they aren't found in the global symbol table of all loaded
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// modules. This map is indexed by symbol name.
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StringMap<RelocationList> ExternalSymbolRelocations;
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typedef std::map<RelocationValueRef, uintptr_t> StubMap;
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Triple::ArchType Arch;
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bool IsTargetLittleEndian;
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// True if all sections should be passed to the memory manager, false if only
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// sections containing relocations should be. Defaults to 'false'.
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bool ProcessAllSections;
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// This mutex prevents simultaneously loading objects from two different
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// threads. This keeps us from having to protect individual data structures
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// and guarantees that section allocation requests to the memory manager
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// won't be interleaved between modules. It is also used in mapSectionAddress
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// and resolveRelocations to protect write access to internal data structures.
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//
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// loadObject may be called on the same thread during the handling of of
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// processRelocations, and that's OK. The handling of the relocation lists
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// is written in such a way as to work correctly if new elements are added to
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// the end of the list while the list is being processed.
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sys::Mutex lock;
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virtual unsigned getMaxStubSize() = 0;
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virtual unsigned getStubAlignment() = 0;
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bool HasError;
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std::string ErrorStr;
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// Set the error state and record an error string.
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bool Error(const Twine &Msg) {
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ErrorStr = Msg.str();
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HasError = true;
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return true;
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}
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uint64_t getSectionLoadAddress(unsigned SectionID) const {
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return Sections[SectionID].LoadAddress;
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}
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uint8_t *getSectionAddress(unsigned SectionID) const {
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return (uint8_t *)Sections[SectionID].Address;
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}
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void writeInt16BE(uint8_t *Addr, uint16_t Value) {
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if (IsTargetLittleEndian)
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sys::swapByteOrder(Value);
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*Addr = (Value >> 8) & 0xFF;
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*(Addr + 1) = Value & 0xFF;
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}
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void writeInt32BE(uint8_t *Addr, uint32_t Value) {
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if (IsTargetLittleEndian)
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sys::swapByteOrder(Value);
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*Addr = (Value >> 24) & 0xFF;
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*(Addr + 1) = (Value >> 16) & 0xFF;
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*(Addr + 2) = (Value >> 8) & 0xFF;
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*(Addr + 3) = Value & 0xFF;
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}
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void writeInt64BE(uint8_t *Addr, uint64_t Value) {
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if (IsTargetLittleEndian)
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sys::swapByteOrder(Value);
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*Addr = (Value >> 56) & 0xFF;
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*(Addr + 1) = (Value >> 48) & 0xFF;
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*(Addr + 2) = (Value >> 40) & 0xFF;
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*(Addr + 3) = (Value >> 32) & 0xFF;
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*(Addr + 4) = (Value >> 24) & 0xFF;
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*(Addr + 5) = (Value >> 16) & 0xFF;
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*(Addr + 6) = (Value >> 8) & 0xFF;
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*(Addr + 7) = Value & 0xFF;
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}
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/// Endian-aware read Read the least significant Size bytes from Src.
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uint64_t readBytesUnaligned(uint8_t *Src, unsigned Size) const;
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/// Endian-aware write. Write the least significant Size bytes from Value to
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/// Dst.
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void writeBytesUnaligned(uint64_t Value, uint8_t *Dst, unsigned Size) const;
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/// \brief Given the common symbols discovered in the object file, emit a
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/// new section for them and update the symbol mappings in the object and
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/// symbol table.
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void emitCommonSymbols(const ObjectFile &Obj,
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const CommonSymbolMap &CommonSymbols,
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uint64_t TotalSize, RTDyldSymbolTable &SymbolTable);
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/// \brief Emits section data from the object file to the MemoryManager.
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/// \param IsCode if it's true then allocateCodeSection() will be
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/// used for emits, else allocateDataSection() will be used.
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/// \return SectionID.
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unsigned emitSection(const ObjectFile &Obj, const SectionRef &Section,
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bool IsCode);
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/// \brief Find Section in LocalSections. If the secton is not found - emit
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/// it and store in LocalSections.
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/// \param IsCode if it's true then allocateCodeSection() will be
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/// used for emmits, else allocateDataSection() will be used.
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/// \return SectionID.
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unsigned findOrEmitSection(const ObjectFile &Obj, const SectionRef &Section,
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bool IsCode, ObjSectionToIDMap &LocalSections);
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// \brief Add a relocation entry that uses the given section.
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void addRelocationForSection(const RelocationEntry &RE, unsigned SectionID);
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// \brief Add a relocation entry that uses the given symbol. This symbol may
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// be found in the global symbol table, or it may be external.
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void addRelocationForSymbol(const RelocationEntry &RE, StringRef SymbolName);
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/// \brief Emits long jump instruction to Addr.
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/// \return Pointer to the memory area for emitting target address.
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uint8_t *createStubFunction(uint8_t *Addr, unsigned AbiVariant = 0);
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/// \brief Resolves relocations from Relocs list with address from Value.
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void resolveRelocationList(const RelocationList &Relocs, uint64_t Value);
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/// \brief A object file specific relocation resolver
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/// \param RE The relocation to be resolved
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/// \param Value Target symbol address to apply the relocation action
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virtual void resolveRelocation(const RelocationEntry &RE, uint64_t Value) = 0;
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/// \brief Parses one or more object file relocations (some object files use
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/// relocation pairs) and stores it to Relocations or SymbolRelocations
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/// (this depends on the object file type).
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/// \return Iterator to the next relocation that needs to be parsed.
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virtual relocation_iterator
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processRelocationRef(unsigned SectionID, relocation_iterator RelI,
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const ObjectFile &Obj, ObjSectionToIDMap &ObjSectionToID,
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StubMap &Stubs) = 0;
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/// \brief Resolve relocations to external symbols.
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void resolveExternalSymbols();
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/// \brief Update GOT entries for external symbols.
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// The base class does nothing. ELF overrides this.
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virtual void updateGOTEntries(StringRef Name, uint64_t Addr) {}
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// \brief Compute an upper bound of the memory that is required to load all
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// sections
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void computeTotalAllocSize(const ObjectFile &Obj, uint64_t &CodeSize,
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uint64_t &DataSizeRO, uint64_t &DataSizeRW);
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// \brief Compute the stub buffer size required for a section
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unsigned computeSectionStubBufSize(const ObjectFile &Obj,
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const SectionRef &Section);
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// \brief Implementation of the generic part of the loadObject algorithm.
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std::pair<unsigned, unsigned> loadObjectImpl(const object::ObjectFile &Obj);
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public:
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RuntimeDyldImpl(RTDyldMemoryManager *mm)
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: MemMgr(mm), Checker(nullptr), ProcessAllSections(false), HasError(false) {
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}
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virtual ~RuntimeDyldImpl();
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void setProcessAllSections(bool ProcessAllSections) {
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this->ProcessAllSections = ProcessAllSections;
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}
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void setRuntimeDyldChecker(RuntimeDyldCheckerImpl *Checker) {
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this->Checker = Checker;
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}
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virtual std::unique_ptr<RuntimeDyld::LoadedObjectInfo>
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loadObject(const object::ObjectFile &Obj) = 0;
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uint8_t* getSymbolAddress(StringRef Name) const {
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// FIXME: Just look up as a function for now. Overly simple of course.
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// Work in progress.
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RTDyldSymbolTable::const_iterator pos = GlobalSymbolTable.find(Name);
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if (pos == GlobalSymbolTable.end())
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return nullptr;
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const auto &SymInfo = pos->second;
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return getSectionAddress(SymInfo.getSectionID()) + SymInfo.getOffset();
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}
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uint64_t getSymbolLoadAddress(StringRef Name) const {
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// FIXME: Just look up as a function for now. Overly simple of course.
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// Work in progress.
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RTDyldSymbolTable::const_iterator pos = GlobalSymbolTable.find(Name);
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if (pos == GlobalSymbolTable.end())
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return 0;
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const auto &SymInfo = pos->second;
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return getSectionLoadAddress(SymInfo.getSectionID()) + SymInfo.getOffset();
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}
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uint64_t getExportedSymbolLoadAddress(StringRef Name) const {
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RTDyldSymbolTable::const_iterator pos = GlobalSymbolTable.find(Name);
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if (pos == GlobalSymbolTable.end())
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return 0;
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const auto &SymInfo = pos->second;
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if (SymInfo.getVisibility() == SymbolInfo::Hidden)
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return 0;
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return getSectionLoadAddress(SymInfo.getSectionID()) + SymInfo.getOffset();
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}
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void resolveRelocations();
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void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
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void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
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// Is the linker in an error state?
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bool hasError() { return HasError; }
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// Mark the error condition as handled and continue.
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void clearError() { HasError = false; }
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// Get the error message.
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StringRef getErrorString() { return ErrorStr; }
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virtual bool isCompatibleFile(const ObjectFile &Obj) const = 0;
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virtual void registerEHFrames();
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virtual void deregisterEHFrames();
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virtual void finalizeLoad(const ObjectFile &ObjImg,
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ObjSectionToIDMap &SectionMap) {}
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};
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} // end namespace llvm
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#endif
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