| //== PointerIterationChecker.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 file defines PointerIterationChecker which checks for non-determinism |
| // caused due to iteration of unordered containers of pointer elements. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/ASTMatchers/ASTMatchFinder.h" |
| #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h" |
| #include "clang/StaticAnalyzer/Core/Checker.h" |
| #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" |
| |
| using namespace clang; |
| using namespace ento; |
| using namespace ast_matchers; |
| |
| namespace { |
| |
| // ID of a node at which the diagnostic would be emitted. |
| constexpr llvm::StringLiteral WarnAtNode = "iter"; |
| |
| class PointerIterationChecker : public Checker<check::ASTCodeBody> { |
| public: |
| void checkASTCodeBody(const Decl *D, |
| AnalysisManager &AM, |
| BugReporter &BR) const; |
| }; |
| |
| static void emitDiagnostics(const BoundNodes &Match, const Decl *D, |
| BugReporter &BR, AnalysisManager &AM, |
| const PointerIterationChecker *Checker) { |
| auto *ADC = AM.getAnalysisDeclContext(D); |
| |
| const auto *MarkedStmt = Match.getNodeAs<Stmt>(WarnAtNode); |
| assert(MarkedStmt); |
| |
| auto Range = MarkedStmt->getSourceRange(); |
| auto Location = PathDiagnosticLocation::createBegin(MarkedStmt, |
| BR.getSourceManager(), |
| ADC); |
| std::string Diagnostics; |
| llvm::raw_string_ostream OS(Diagnostics); |
| OS << "Iteration of pointer-like elements " |
| << "can result in non-deterministic ordering"; |
| |
| BR.EmitBasicReport(ADC->getDecl(), Checker, |
| "Iteration of pointer-like elements", "Non-determinism", |
| OS.str(), Location, Range); |
| } |
| |
| // Assumption: Iteration of ordered containers of pointers is deterministic. |
| |
| // TODO: Currently, we only check for std::unordered_set. Other unordered |
| // containers like std::unordered_map also need to be handled. |
| |
| // TODO: Currently, we do not check what the for loop does with the iterated |
| // pointer values. Not all iterations may cause non-determinism. For example, |
| // counting or summing up the elements should not be non-deterministic. |
| |
| auto matchUnorderedIterWithPointers() -> decltype(decl()) { |
| |
| auto UnorderedContainerM = declRefExpr(to(varDecl(hasType( |
| recordDecl(hasName("std::unordered_set") |
| ))))); |
| |
| auto PointerTypeM = varDecl(hasType(hasCanonicalType(pointerType()))); |
| |
| auto PointerIterM = stmt(cxxForRangeStmt( |
| hasLoopVariable(PointerTypeM), |
| hasRangeInit(UnorderedContainerM) |
| )).bind(WarnAtNode); |
| |
| return decl(forEachDescendant(PointerIterM)); |
| } |
| |
| void PointerIterationChecker::checkASTCodeBody(const Decl *D, |
| AnalysisManager &AM, |
| BugReporter &BR) const { |
| auto MatcherM = matchUnorderedIterWithPointers(); |
| |
| auto Matches = match(MatcherM, *D, AM.getASTContext()); |
| for (const auto &Match : Matches) |
| emitDiagnostics(Match, D, BR, AM, this); |
| } |
| |
| } // end of anonymous namespace |
| |
| void ento::registerPointerIterationChecker(CheckerManager &Mgr) { |
| Mgr.registerChecker<PointerIterationChecker>(); |
| } |
| |
| bool ento::shouldRegisterPointerIterationChecker(const CheckerManager &mgr) { |
| const LangOptions &LO = mgr.getLangOpts(); |
| return LO.CPlusPlus; |
| } |