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//===-- llvm/MC/MCObjectDisassembler.h --------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains the declaration of the MCObjectDisassembler class, which
// can be used to construct an MCModule and an MC CFG from an ObjectFile.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCOBJECTDISASSEMBLER_H
#define LLVM_MC_MCOBJECTDISASSEMBLER_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/DataTypes.h"
#include "llvm/Support/MemoryObject.h"
#include <vector>
namespace llvm {
namespace object {
class ObjectFile;
class MachOObjectFile;
}
class MCBasicBlock;
class MCDisassembler;
class MCFunction;
class MCInstrAnalysis;
class MCModule;
class MCObjectSymbolizer;
/// \brief Disassemble an ObjectFile to an MCModule and MCFunctions.
/// This class builds on MCDisassembler to disassemble whole sections, creating
/// MCAtom (MCTextAtom for disassembled sections and MCDataAtom for raw data).
/// It can also be used to create a control flow graph consisting of MCFunctions
/// and MCBasicBlocks.
class MCObjectDisassembler {
public:
MCObjectDisassembler(const object::ObjectFile &Obj,
const MCDisassembler &Dis,
const MCInstrAnalysis &MIA);
virtual ~MCObjectDisassembler() {}
/// \brief Build an MCModule, creating atoms and optionally functions.
/// \param withCFG Also build a CFG by adding MCFunctions to the Module.
/// If withCFG is false, the MCModule built only contains atoms, representing
/// what was found in the object file. If withCFG is true, MCFunctions are
/// created, containing MCBasicBlocks. All text atoms are split to form basic
/// block atoms, which then each back an MCBasicBlock.
MCModule *buildModule(bool withCFG = false);
MCModule *buildEmptyModule();
typedef std::vector<uint64_t> AddressSetTy;
/// \name Create a new MCFunction.
MCFunction *createFunction(MCModule *Module, uint64_t BeginAddr,
AddressSetTy &CallTargets,
AddressSetTy &TailCallTargets);
/// \brief Set the region on which to fallback if disassembly was requested
/// somewhere not accessible in the object file.
/// This is used for dynamic disassembly (see RawMemoryObject).
void setFallbackRegion(OwningPtr<MemoryObject> &Region) {
FallbackRegion.reset(Region.release());
}
/// \brief Set the symbolizer to use to get information on external functions.
/// Note that this isn't used to do instruction-level symbolization (that is,
/// plugged into MCDisassembler), but to symbolize function call targets.
void setSymbolizer(MCObjectSymbolizer *ObjectSymbolizer) {
MOS = ObjectSymbolizer;
}
/// \brief Get the effective address of the entrypoint, or 0 if there is none.
virtual uint64_t getEntrypoint();
/// \name Get the addresses of static constructors/destructors in the object.
/// The caller is expected to know how to interpret the addresses;
/// for example, Mach-O init functions expect 5 arguments, not for ELF.
/// The addresses are original object file load addresses, not effective.
/// @{
virtual ArrayRef<uint64_t> getStaticInitFunctions();
virtual ArrayRef<uint64_t> getStaticExitFunctions();
/// @}
/// \name Translation between effective and objectfile load address.
/// @{
/// \brief Compute the effective load address, from an objectfile virtual
/// address. This is implemented in a format-specific way, to take into
/// account things like PIE/ASLR when doing dynamic disassembly.
/// For example, on Mach-O this would be done by adding the VM addr slide,
/// on glibc ELF by keeping a map between segment load addresses, filled
/// using dl_iterate_phdr, etc..
/// In most static situations and in the default impl., this returns \p Addr.
virtual uint64_t getEffectiveLoadAddr(uint64_t Addr);
/// \brief Compute the original load address, as specified in the objectfile.
/// This is the inverse of getEffectiveLoadAddr.
virtual uint64_t getOriginalLoadAddr(uint64_t EffectiveAddr);
/// @}
protected:
const object::ObjectFile &Obj;
const MCDisassembler &Dis;
const MCInstrAnalysis &MIA;
MCObjectSymbolizer *MOS;
/// \brief The fallback memory region, outside the object file.
OwningPtr<MemoryObject> FallbackRegion;
/// \brief Return a memory region suitable for reading starting at \p Addr.
/// In most cases, this returns a StringRefMemoryObject backed by the
/// containing section. When no section was found, this returns the
/// FallbackRegion, if it is suitable.
/// If it is not, or if there is no fallback region, this returns 0.
MemoryObject *getRegionFor(uint64_t Addr);
private:
/// \brief Fill \p Module by creating an atom for each section.
/// This could be made much smarter, using information like symbols, but also
/// format-specific features, like mach-o function_start or data_in_code LCs.
void buildSectionAtoms(MCModule *Module);
/// \brief Enrich \p Module with a CFG consisting of MCFunctions.
/// \param Module An MCModule returned by buildModule, with no CFG.
/// NOTE: Each MCBasicBlock in a MCFunction is backed by a single MCTextAtom.
/// When the CFG is built, contiguous instructions that were previously in a
/// single MCTextAtom will be split in multiple basic block atoms.
void buildCFG(MCModule *Module);
MCBasicBlock *getBBAt(MCModule *Module, MCFunction *MCFN, uint64_t BeginAddr,
AddressSetTy &CallTargets,
AddressSetTy &TailCallTargets);
};
class MCMachOObjectDisassembler : public MCObjectDisassembler {
const object::MachOObjectFile &MOOF;
uint64_t VMAddrSlide;
uint64_t HeaderLoadAddress;
// __DATA;__mod_init_func support.
llvm::StringRef ModInitContents;
// __DATA;__mod_exit_func support.
llvm::StringRef ModExitContents;
public:
/// \brief Construct a Mach-O specific object disassembler.
/// \param VMAddrSlide The virtual address slide applied by dyld.
/// \param HeaderLoadAddress The load address of the mach_header for this
/// object.
MCMachOObjectDisassembler(const object::MachOObjectFile &MOOF,
const MCDisassembler &Dis,
const MCInstrAnalysis &MIA, uint64_t VMAddrSlide,
uint64_t HeaderLoadAddress);
protected:
uint64_t getEffectiveLoadAddr(uint64_t Addr) override;
uint64_t getOriginalLoadAddr(uint64_t EffectiveAddr) override;
uint64_t getEntrypoint() override;
ArrayRef<uint64_t> getStaticInitFunctions() override;
ArrayRef<uint64_t> getStaticExitFunctions() override;
};
}
#endif
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