//===--- UndefinedArraySubscriptChecker.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 defines UndefinedArraySubscriptChecker, a builtin check in ExprEngine

// that performs checks for undefined array subscripts.

//

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

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

#include "clang/AST/DeclCXX.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"

using namespace clang;

using namespace ento;

namespace {

class UndefinedArraySubscriptChecker

  : public Checker< check::PreStmt<ArraySubscriptExpr> > {

  mutable std::unique_ptr<BugType> BT;

public:

  void checkPreStmt(const ArraySubscriptExpr *A, CheckerContext &C) const;

};

} // end anonymous namespace

void

UndefinedArraySubscriptChecker::checkPreStmt(const ArraySubscriptExpr *A,

                                             CheckerContext &C) const {

  const Expr *Index = A->getIdx();

  if (!C.getSVal(Index).isUndef())

    return;

  // Sema generates anonymous array variables for copying array struct fields.

  // Don't warn if we're in an implicitly-generated constructor.

  const Decl *D = C.getLocationContext()->getDecl();

  if (const CXXConstructorDecl *Ctor = dyn_cast<CXXConstructorDecl>(D))

    if (Ctor->isDefaulted())

      return;

  ExplodedNode *N = C.generateErrorNode();

  if (!N)

    return;

  if (!BT)

    BT.reset(new BugType(this, "Array subscript is undefined"));

  // Generate a report for this bug.

  auto R = std::make_unique<PathSensitiveBugReport>(*BT, BT->getDescription(), N);

  R->addRange(A->getIdx()->getSourceRange());

  bugreporter::trackExpressionValue(N, A->getIdx(), *R);

  C.emitReport(std::move(R));

}

void ento::registerUndefinedArraySubscriptChecker(CheckerManager &mgr) {

  mgr.registerChecker<UndefinedArraySubscriptChecker>();

}

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

  return true;

}