CachedConstAccessorsLattice.h

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//===-- CachedConstAccessorsLattice.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 the lattice mixin that additionally maintains a cache of
// stable method call return values to model const accessor member functions.
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_CACHED_CONST_ACCESSORS_LATTICE_H
#define LLVM_CLANG_ANALYSIS_FLOWSENSITIVE_CACHED_CONST_ACCESSORS_LATTICE_H
 
#include "clang/AST/Decl.h"
#include "clang/AST/Expr.h"
#include "clang/AST/Type.h"
#include "clang/Analysis/FlowSensitive/DataflowEnvironment.h"
#include "clang/Analysis/FlowSensitive/DataflowLattice.h"
#include "clang/Analysis/FlowSensitive/StorageLocation.h"
#include "clang/Analysis/FlowSensitive/Value.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/STLFunctionalExtras.h"
 
namespace clang {
namespace dataflow {
 
/// A mixin for a lattice that additionally maintains a cache of stable method
/// call return values to model const accessors methods. When a non-const method
/// is called, the cache should be cleared causing the next call to a const
/// method to be considered a different value. NOTE: The user is responsible for
/// clearing the cache.
///
/// For example:
///
/// class Bar {
/// public:
///   const std::optional<Foo>& getFoo() const;
///   void clear();
/// };
//
/// void func(Bar& s) {
///   if (s.getFoo().has_value()) {
///     use(s.getFoo().value()); // safe (checked earlier getFoo())
///     s.clear();
///     use(s.getFoo().value()); // unsafe (invalidate cache for s)
///   }
/// }