diff options
Diffstat (limited to 'lib/StaticAnalyzer/Checkers/PointerIterationChecker.cpp')
-rw-r--r-- | lib/StaticAnalyzer/Checkers/PointerIterationChecker.cpp | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Checkers/PointerIterationChecker.cpp b/lib/StaticAnalyzer/Checkers/PointerIterationChecker.cpp new file mode 100644 index 000000000000..307e59b8eebc --- /dev/null +++ b/lib/StaticAnalyzer/Checkers/PointerIterationChecker.cpp @@ -0,0 +1,100 @@ +//== 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 LangOptions &LO) { + return LO.CPlusPlus; +} |