//== TrustReturnsNonnullChecker.cpp -- API nullability modeling -*- 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 nullability-related assumptions to methods annotated with

// returns_nonnull attribute.

//

//===----------------------------------------------------------------------===//

#include "clang/AST/Attr.h"

#include "clang/AST/Decl.h"

#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"

#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"

using namespace clang;

using namespace ento;

namespace {

class TrustReturnsNonnullChecker : public Checker<check::PostCall> {

public:

  TrustReturnsNonnullChecker(ASTContext &Ctx) {}

  void checkPostCall(const CallEvent &Call, CheckerContext &C) const {

    ProgramStateRef State = C.getState();

    if (isNonNullPtr(Call))

      if (auto L = Call.getReturnValue().getAs<Loc>())

        State = State->assume(*L, /*assumption=*/true);

    C.addTransition(State);

  }

private:

  /// \returns Whether the method declaration has the attribute returns_nonnull.

  bool isNonNullPtr(const CallEvent &Call) const {

    QualType ExprRetType = Call.getResultType();

    const Decl *CallDeclaration =  Call.getDecl();

    if (!ExprRetType->isAnyPointerType() || 
!CallDeclaration9
)

      return false;

    return CallDeclaration->hasAttr<ReturnsNonNullAttr>();

  }

};

} // namespace

void ento::registerTrustReturnsNonnullChecker(CheckerManager &Mgr) {

  Mgr.registerChecker<TrustReturnsNonnullChecker>(Mgr.getASTContext());

}

bool ento::shouldRegisterTrustReturnsNonnullChecker(const CheckerManager &mgr) {

  return true;

}