//===-- RuntimeDyld.h - 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.
//
//===----------------------------------------------------------------------===//
//
// Interface for the runtime dynamic linker facilities of the MC-JIT.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
#define LLVM_EXECUTIONENGINE_RUNTIMEDYLD_H
#include "JITSymbolFlags.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/Memory.h"
#include "llvm/DebugInfo/DIContext.h"
#include <memory>
namespace llvm {
namespace object {
class ObjectFile;
template <typename T> class OwningBinary;
}
class RuntimeDyldImpl;
class RuntimeDyldCheckerImpl;
class RuntimeDyld {
friend class RuntimeDyldCheckerImpl;
RuntimeDyld(const RuntimeDyld &) = delete;
void operator=(const RuntimeDyld &) = delete;
protected:
// Change the address associated with a section when resolving relocations.
// Any relocations already associated with the symbol will be re-resolved.
void reassignSectionAddress(unsigned SectionID, uint64_t Addr);
public:
/// \brief Information about a named symbol.
class SymbolInfo : public JITSymbolBase {
public:
SymbolInfo(std::nullptr_t) : JITSymbolBase(JITSymbolFlags::None), Address(0) {}
SymbolInfo(uint64_t Address, JITSymbolFlags Flags)
: JITSymbolBase(Flags), Address(Address) {}
explicit operator bool() const { return Address != 0; }
uint64_t getAddress() const { return Address; }
private:
uint64_t Address;
};
/// \brief Information about the loaded object.
class LoadedObjectInfo : public llvm::LoadedObjectInfo {
friend class RuntimeDyldImpl;
public:
LoadedObjectInfo(RuntimeDyldImpl &RTDyld, unsigned BeginIdx,
unsigned EndIdx)
: RTDyld(RTDyld), BeginIdx(BeginIdx), EndIdx(EndIdx) { }
virtual object::OwningBinary<object::ObjectFile>
getObjectForDebug(const object::ObjectFile &Obj) const = 0;
uint64_t getSectionLoadAddress(StringRef Name) const;
protected:
virtual void anchor();
RuntimeDyldImpl &RTDyld;
unsigned BeginIdx, EndIdx;
};
template <typename Derived> struct LoadedObjectInfoHelper : LoadedObjectInfo {
LoadedObjectInfoHelper(RuntimeDyldImpl &RTDyld, unsigned BeginIdx,
unsigned EndIdx)
: LoadedObjectInfo(RTDyld, BeginIdx, EndIdx) {}
std::unique_ptr<llvm::LoadedObjectInfo> clone() const override {
return llvm::make_unique<Derived>(static_cast<const Derived &>(*this));
}
};
/// \brief Memory Management.
class MemoryManager {
public:
virtual ~MemoryManager() {};
/// Allocate a memory block of (at least) the given size suitable for
/// executable code. The SectionID is a unique identifier assigned by the
/// RuntimeDyld instance, and optionally recorded by the memory manager to
/// access a loaded section.
virtual uint8_t *allocateCodeSection(uintptr_t Size, unsigned Alignment,
unsigned SectionID,
StringRef SectionName) = 0;
/// Allocate a memory block of (at least) the given size suitable for data.
/// The SectionID is a unique identifier assigned by the JIT engine, and
/// optionally recorded by the memory manager to access a loaded section.
virtual uint8_t *allocateDataSection(uintptr_t Size, unsigned Alignment,
unsigned SectionID,
StringRef SectionName,
bool IsReadOnly) = 0;
/// Inform the memory manager about the total amount of memory required to
/// allocate all sections to be loaded:
/// \p CodeSize - the total size of all code sections
/// \p DataSizeRO - the total size of all read-only data sections
/// \p DataSizeRW - the total size of all read-write data sections
///
/// Note that by default the callback is disabled. To enable it
/// redefine the method needsToReserveAllocationSpace to return true.
virtual void reserveAllocationSpace(uintptr_t CodeSize,
uintptr_t DataSizeRO,
uintptr_t DataSizeRW) {}
/// Override to return true to enable the reserveAllocationSpace callback.
virtual bool needsToReserveAllocationSpace() { return false; }
/// Register the EH frames with the runtime so that c++ exceptions work.
///
/// \p Addr parameter provides the local address of the EH frame section
/// data, while \p LoadAddr provides the address of the data in the target
/// address space. If the section has not been remapped (which will usually
/// be the case for local execution) these two values will be the same.
virtual void registerEHFrames(uint8_t *Addr, uint64_t LoadAddr,
size_t Size) = 0;
virtual void deregisterEHFrames(uint8_t *addr, uint64_t LoadAddr,
size_t Size) = 0;
/// This method is called when object loading is complete and section page
/// permissions can be applied. It is up to the memory manager implementation
/// to decide whether or not to act on this method. The memory manager will
/// typically allocate all sections as read-write and then apply specific
/// permissions when this method is called. Code sections cannot be executed
/// until this function has been called. In addition, any cache coherency
/// operations needed to reliably use the memory are also performed.
///
/// Returns true if an error occurred, false otherwise.
virtual bool finalizeMemory(std::string *ErrMsg = nullptr) = 0;
private:
virtual void anchor();
};
/// \brief Symbol resolution.
class SymbolResolver {
public:
virtual ~SymbolResolver() {};
/// This method returns the address of the specified function or variable.
/// It is used to resolve symbols during module linking.
virtual SymbolInfo findSymbol(const std::string &Name) = 0;
/// This method returns the address of the specified symbol if it exists
/// within the logical dynamic library represented by this
/// RTDyldMemoryManager. Unlike getSymbolAddress, queries through this
/// interface should return addresses for hidden symbols.
///
/// This is of particular importance for the Orc JIT APIs, which support lazy
/// compilation by breaking up modules: Each of those broken out modules
/// must be able to resolve hidden symbols provided by the others. Clients
/// writing memory managers for MCJIT can usually ignore this method.
///
/// This method will be queried by RuntimeDyld when checking for previous
/// definitions of common symbols. It will *not* be queried by default when
/// resolving external symbols (this minimises the link-time overhead for
/// MCJIT clients who don't care about Orc features). If you are writing a
/// RTDyldMemoryManager for Orc and want "external" symbol resolution to
/// search the logical dylib, you should override your getSymbolAddress
/// method call this method directly.
virtual SymbolInfo findSymbolInLogicalDylib(const std::string &Name) = 0;
private:
virtual void anchor();
};
/// \brief Construct a RuntimeDyld instance.
RuntimeDyld(MemoryManager &MemMgr, SymbolResolver &Resolver);
~RuntimeDyld();
/// Add the referenced object file to the list of objects to be loaded and
/// relocated.
std::unique_ptr<LoadedObjectInfo> loadObject(const object::ObjectFile &O);
/// Get the address of our local copy of the symbol. This may or may not
/// be the address used for relocation (clients can copy the data around
/// and resolve relocatons based on where they put it).
void *getSymbolLocalAddress(StringRef Name) const;
/// Get the target address and flags for the named symbol.
/// This address is the one used for relocation.
SymbolInfo getSymbol(StringRef Name) const;
/// Resolve the relocations for all symbols we currently know about.
void resolveRelocations();
/// Map a section to its target address space value.
/// Map the address of a JIT section as returned from the memory manager
/// to the address in the target process as the running code will see it.
/// This is the address which will be used for relocation resolution.
void mapSectionAddress(const void *LocalAddress, uint64_t TargetAddress);
/// Register any EH frame sections that have been loaded but not previously
/// registered with the memory manager. Note, RuntimeDyld is responsible
/// for identifying the EH frame and calling the memory manager with the
/// EH frame section data. However, the memory manager itself will handle
/// the actual target-specific EH frame registration.
void registerEHFrames();
void deregisterEHFrames();
bool hasError();
StringRef getErrorString();
/// By default, only sections that are "required for execution" are passed to
/// the RTDyldMemoryManager, and other sections are discarded. Passing 'true'
/// to this method will cause RuntimeDyld to pass all sections to its
/// memory manager regardless of whether they are "required to execute" in the
/// usual sense. This is useful for inspecting metadata sections that may not
/// contain relocations, E.g. Debug info, stackmaps.
///
/// Must be called before the first object file is loaded.
void setProcessAllSections(bool ProcessAllSections) {
assert(!Dyld && "setProcessAllSections must be called before loadObject.");
this->ProcessAllSections = ProcessAllSections;
}
private:
// RuntimeDyldImpl is the actual class. RuntimeDyld is just the public
// interface.
std::unique_ptr<RuntimeDyldImpl> Dyld;
MemoryManager &MemMgr;
SymbolResolver &Resolver;
bool ProcessAllSections;
RuntimeDyldCheckerImpl *Checker;
};
} // end namespace llvm
#endif
