llvm/clang/include/clang/Analysis/FlowSensitive/StorageLocation.h

//===-- StorageLocation.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
//
//===----------------------------------------------------------------------===//
//
// This file defines classes that represent elements of the local variable store
// and of the heap during dataflow analysis.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_STORAGELOCATION_H
#define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_STORAGELOCATION_H

#include "clang/AST/Decl.h"
#include "clang/AST/Type.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/Support/Debug.h"
#include <cassert>

#define DEBUG_TYPE …

namespace clang {
namespace dataflow {

/// Base class for elements of the local variable store and of the heap.
///
/// Each storage location holds a value. The mapping from storage locations to
/// values is stored in the environment.
class StorageLocation { … };

/// A storage location that is not subdivided further for the purposes of
/// abstract interpretation. For example: `int`, `int*`, `int&`.
class ScalarStorageLocation final : public StorageLocation { … };

/// A storage location for a record (struct, class, or union).
///
/// Contains storage locations for all modeled fields of the record (also
/// referred to as "children"). The child map is flat, so accessible members of
/// the base class are directly accessible as children of this location.
///
/// Record storage locations may also contain so-called synthetic fields. These
/// are typically used to model the internal state of a class (e.g. the value
/// stored in a `std::optional`) without having to depend on that class's
/// implementation details. All `RecordStorageLocation`s of a given type should
/// have the same synthetic fields.
///
/// The storage location for a field of reference type may be null. This
/// typically occurs in one of two situations:
/// - The record has not been fully initialized.
/// - The maximum depth for modelling a self-referential data structure has been
///   reached.
/// Storage locations for fields of all other types must be non-null.
///
/// FIXME: Currently, the storage location of unions is modelled the same way as
/// that of structs or classes. Eventually, we need to change this modelling so
/// that all of the members of a given union have the same storage location.
class RecordStorageLocation final : public StorageLocation { … };

} // namespace dataflow
} // namespace clang

#undef DEBUG_TYPE

#endif // LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_STORAGELOCATION_H