llvm/lld/MachO/ConcatOutputSection.h

//===- ConcatOutputSection.h ------------------------------------*- 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
//
//===----------------------------------------------------------------------===//

#ifndef LLD_MACHO_CONCAT_OUTPUT_SECTION_H
#define LLD_MACHO_CONCAT_OUTPUT_SECTION_H

#include "InputSection.h"
#include "OutputSection.h"
#include "lld/Common/LLVM.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/MapVector.h"

namespace lld::macho {

class Defined;

// Linking multiple files will inevitably mean resolving sections in different
// files that are labeled with the same segment and section name. This class
// contains all such sections and writes the data from each section sequentially
// in the final binary.
class ConcatOutputSection : public OutputSection { … };

// ConcatOutputSections that contain code (text) require special handling to
// support thunk insertion.
class TextOutputSection : public ConcatOutputSection { … };

// We maintain one ThunkInfo per real function.
//
// The "active thunk" is represented by the sym/isec pair that
// turns-over during finalize(): as the call-site address advances,
// the active thunk goes out of branch-range, and we create a new
// thunk to take its place.
//
// The remaining members -- bools and counters -- apply to the
// collection of thunks associated with the real function.

struct ThunkInfo { … };

NamePair maybeRenameSection(NamePair key);

// Output sections are added to output segments in iteration order
// of ConcatOutputSection, so must have deterministic iteration order.
extern llvm::MapVector<NamePair, ConcatOutputSection *> concatOutputSections;

extern llvm::DenseMap<Symbol *, ThunkInfo> thunkMap;

} // namespace lld::macho

#endif