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//===-- llvm/MC/MCDisassembler.h - Disassembler interface -------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
#include "llvm-c/Disassembler.h"
#include "llvm/MC/MCRelocationInfo.h"
#include "llvm/MC/MCSymbolizer.h"
#include "llvm/Support/DataTypes.h"
namespace llvm {
class MCInst;
class MCSubtargetInfo;
class MemoryObject;
class raw_ostream;
class MCContext;
/// MCDisassembler - Superclass for all disassemblers. Consumes a memory region
/// and provides an array of assembly instructions.
class MCDisassembler {
/// Ternary decode status. Most backends will just use Fail and
/// Success, however some have a concept of an instruction with
/// understandable semantics but which is architecturally
/// incorrect. An example of this is ARM UNPREDICTABLE instructions
/// which are disassemblable but cause undefined behaviour.
/// Because it makes sense to disassemble these instructions, there
/// is a "soft fail" failure mode that indicates the MCInst& is
/// valid but architecturally incorrect.
/// The enum numbers are deliberately chosen such that reduction
/// from Success->SoftFail ->Fail can be done with a simple
/// bitwise-AND:
/// LEFT & TOP = | Success Unpredictable Fail
/// --------------+-----------------------------------
/// Success | Success Unpredictable Fail
/// Unpredictable | Unpredictable Unpredictable Fail
/// Fail | Fail Fail Fail
/// An easy way of encoding this is as 0b11, 0b01, 0b00 for
/// Success, SoftFail, Fail respectively.
enum DecodeStatus {
Fail = 0,
SoftFail = 1,
Success = 3
/// Constructor - Performs initial setup for the disassembler.
MCDisassembler(const MCSubtargetInfo &STI, MCContext &Ctx)
: Ctx(Ctx), STI(STI), Symbolizer(), CommentStream(nullptr) {}
virtual ~MCDisassembler();
/// getInstruction - Returns the disassembly of a single instruction.
/// @param instr - An MCInst to populate with the contents of the
/// instruction.
/// @param size - A value to populate with the size of the instruction, or
/// the number of bytes consumed while attempting to decode
/// an invalid instruction.
/// @param region - The memory object to use as a source for machine code.
/// @param address - The address, in the memory space of region, of the first
/// byte of the instruction.
/// @param vStream - The stream to print warnings and diagnostic messages on.
/// @param cStream - The stream to print comments and annotations on.
/// @return - MCDisassembler::Success if the instruction is valid,
/// MCDisassembler::SoftFail if the instruction was
/// disassemblable but invalid,
/// MCDisassembler::Fail if the instruction was invalid.
virtual DecodeStatus getInstruction(MCInst& instr,
uint64_t& size,
const MemoryObject &region,
uint64_t address,
raw_ostream &vStream,
raw_ostream &cStream) const = 0;
MCContext &Ctx;
// Subtarget information, for instruction decoding predicates if required.
const MCSubtargetInfo &STI;
std::unique_ptr<MCSymbolizer> Symbolizer;
// Helpers around MCSymbolizer
bool tryAddingSymbolicOperand(MCInst &Inst,
int64_t Value,
uint64_t Address, bool IsBranch,
uint64_t Offset, uint64_t InstSize) const;
void tryAddingPcLoadReferenceComment(int64_t Value, uint64_t Address) const;
/// Set \p Symzer as the current symbolizer.
/// This takes ownership of \p Symzer, and deletes the previously set one.
void setSymbolizer(std::unique_ptr<MCSymbolizer> Symzer);
MCContext& getContext() const { return Ctx; }
const MCSubtargetInfo& getSubtargetInfo() const { return STI; }
// Marked mutable because we cache it inside the disassembler, rather than
// having to pass it around as an argument through all the autogenerated code.
mutable raw_ostream *CommentStream;
} // namespace llvm