llvm/clang/lib/StaticAnalyzer/Checkers/NonnullGlobalConstantsChecker.cpp

//==- NonnullGlobalConstantsChecker.cpp ---------------------------*- 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 checker adds an assumption that constant globals of certain types* are
//  non-null, as otherwise they generally do not convey any useful information.
//  The assumption is useful, as many framework use e. g. global const strings,
//  and the analyzer might not be able to infer the global value if the
//  definition is in a separate translation unit.
//  The following types (and their typedef aliases) are considered to be
//  non-null:
//   - `char* const`
//   - `const CFStringRef` from CoreFoundation
//   - `NSString* const` from Foundation
//   - `CFBooleanRef` from Foundation
//
//===----------------------------------------------------------------------===//

#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
#include "clang/StaticAnalyzer/Core/Checker.h"
#include "clang/StaticAnalyzer/Core/CheckerManager.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
#include <optional>

usingnamespaceclang;
usingnamespaceento;

namespace {

class NonnullGlobalConstantsChecker : public Checker<check::Location> { … };

} // namespace

/// Lazily initialize cache for required identifier information.
void NonnullGlobalConstantsChecker::initIdentifierInfo(ASTContext &Ctx) const { … }

/// Add an assumption that const string-like globals are non-null.
void NonnullGlobalConstantsChecker::checkLocation(SVal location, bool isLoad,
                                                 const Stmt *S,
                                                 CheckerContext &C) const { … }

/// \param V loaded lvalue.
/// \return whether @c val is a string-like const global.
bool NonnullGlobalConstantsChecker::isGlobalConstString(SVal V) const { … }

/// \return whether @c type is extremely unlikely to be null
bool NonnullGlobalConstantsChecker::isNonnullType(QualType Ty) const { … }

void ento::registerNonnullGlobalConstantsChecker(CheckerManager &Mgr) { … }

bool ento::shouldRegisterNonnullGlobalConstantsChecker(const CheckerManager &mgr) { … }