//===- llvm/MC/MCSymbolizer.h - MCSymbolizer class --------------*- 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
//
//===----------------------------------------------------------------------===//
//
// This file contains the declaration of the MCSymbolizer class, which is used
// to symbolize instructions decoded from an object, that is, transform their
// immediate operands to MCExprs.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_MC_MCDISASSEMBLER_MCSYMBOLIZER_H
#define LLVM_MC_MCDISASSEMBLER_MCSYMBOLIZER_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/MC/MCDisassembler/MCRelocationInfo.h"
#include <cstdint>
#include <memory>
#include <utility>
namespace llvm {
class MCContext;
class MCInst;
class raw_ostream;
/// Symbolize and annotate disassembled instructions.
///
/// For now this mimics the old symbolization logic (from both ARM and x86), that
/// relied on user-provided (C API) callbacks to do the actual symbol lookup in
/// the object file. This was moved to MCExternalSymbolizer.
/// A better API would not rely on actually calling the two methods here from
/// inside each disassembler, but would use the instr info to determine what
/// operands are actually symbolizable, and in what way. I don't think this
/// information exists right now.
class MCSymbolizer {
protected:
MCContext &Ctx;
std::unique_ptr<MCRelocationInfo> RelInfo;
public:
/// Construct an MCSymbolizer, taking ownership of \p RelInfo.
MCSymbolizer(MCContext &Ctx, std::unique_ptr<MCRelocationInfo> RelInfo)
: Ctx(Ctx), RelInfo(std::move(RelInfo)) {
}
MCSymbolizer(const MCSymbolizer &) = delete;
MCSymbolizer &operator=(const MCSymbolizer &) = delete;
virtual ~MCSymbolizer();
/// Try to add a symbolic operand instead of \p Value to the MCInst.
///
/// Instead of having a difficult to read immediate, a symbolic operand would
/// represent this immediate in a more understandable way, for instance as a
/// symbol or an offset from a symbol. Relocations can also be used to enrich
/// the symbolic expression.
/// \param Inst - The MCInst where to insert the symbolic operand.
/// \param cStream - Stream to print comments and annotations on.
/// \param Value - Operand value, pc-adjusted by the caller if necessary.
/// \param Address - Load address of the instruction.
/// \param IsBranch - Is the instruction a branch?
/// \param Offset - Byte offset of the operand inside the inst.
/// \param OpSize - Size of the operand in bytes.
/// \param InstSize - Size of the instruction in bytes.
/// \return Whether a symbolic operand was added.
virtual bool tryAddingSymbolicOperand(MCInst &Inst, raw_ostream &cStream,
int64_t Value, uint64_t Address,
bool IsBranch, uint64_t Offset,
uint64_t OpSize, uint64_t InstSize) = 0;
/// Try to add a comment on the PC-relative load.
/// For instance, in Mach-O, this is used to add annotations to instructions
/// that use C string literals, as found in __cstring.
virtual void tryAddingPcLoadReferenceComment(raw_ostream &cStream,
int64_t Value,
uint64_t Address) = 0;
/// Get the MCSymbolizer's list of addresses that were referenced by
/// symbolizable operands but not resolved to a symbol. The caller (some
/// code that is disassembling a section or other chunk of code) would
/// typically create a synthetic label at each address and add them to its
/// list of symbols in the section, before creating a new MCSymbolizer with
/// the enhanced symbol list and retrying disassembling the section.
/// The returned array is unordered and may have duplicates.
/// The returned ArrayRef stops being valid on any call to or destruction of
/// the MCSymbolizer object.
virtual ArrayRef<uint64_t> getReferencedAddresses() const { return {}; }
};
} // end namespace llvm
#endif // LLVM_MC_MCDISASSEMBLER_MCSYMBOLIZER_H