aboutsummaryrefslogtreecommitdiff
path: root/lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp')
-rw-r--r--lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp113
1 files changed, 113 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp b/lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp
new file mode 100644
index 0000000000..586d9d3af2
--- /dev/null
+++ b/lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp
@@ -0,0 +1,113 @@
+//== PointerSortingChecker.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 PointerSortingChecker which checks for non-determinism
+// caused due to sorting containers with pointer-like 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 = "sort";
+
+class PointerSortingChecker : 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 PointerSortingChecker *Checker) {
+ auto *ADC = AM.getAnalysisDeclContext(D);
+
+ const auto *MarkedStmt = Match.getNodeAs<CallExpr>(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 << "Sorting pointer-like elements "
+ << "can result in non-deterministic ordering";
+
+ BR.EmitBasicReport(ADC->getDecl(), Checker,
+ "Sorting of pointer-like elements", "Non-determinism",
+ OS.str(), Location, Range);
+}
+
+auto callsName(const char *FunctionName) -> decltype(callee(functionDecl())) {
+ return callee(functionDecl(hasName(FunctionName)));
+}
+
+// FIXME: Currently we simply check if std::sort is used with pointer-like
+// elements. This approach can have a big false positive rate. Using std::sort,
+// std::unique and then erase is common technique for deduplicating a container
+// (which in some cases might even be quicker than using, let's say std::set).
+// In case a container contains arbitrary memory addresses (e.g. multiple
+// things give different stuff but might give the same thing multiple times)
+// which we don't want to do things with more than once, we might use
+// sort-unique-erase and the sort call will emit a report.
+auto matchSortWithPointers() -> decltype(decl()) {
+ // Match any of these function calls.
+ auto SortFuncM = anyOf(
+ callsName("std::is_sorted"),
+ callsName("std::nth_element"),
+ callsName("std::partial_sort"),
+ callsName("std::partition"),
+ callsName("std::sort"),
+ callsName("std::stable_partition"),
+ callsName("std::stable_sort")
+ );
+
+ // Match only if the container has pointer-type elements.
+ auto IteratesPointerEltsM = hasArgument(0,
+ hasType(cxxRecordDecl(has(
+ fieldDecl(hasType(hasCanonicalType(
+ pointsTo(hasCanonicalType(pointerType()))
+ )))
+ ))));
+
+ auto PointerSortM = stmt(callExpr(allOf(SortFuncM, IteratesPointerEltsM))
+ ).bind(WarnAtNode);
+
+ return decl(forEachDescendant(PointerSortM));
+}
+
+void PointerSortingChecker::checkASTCodeBody(const Decl *D,
+ AnalysisManager &AM,
+ BugReporter &BR) const {
+ auto MatcherM = matchSortWithPointers();
+
+ auto Matches = match(MatcherM, *D, AM.getASTContext());
+ for (const auto &Match : Matches)
+ emitDiagnostics(Match, D, BR, AM, this);
+}
+
+} // end of anonymous namespace
+
+void ento::registerPointerSortingChecker(CheckerManager &Mgr) {
+ Mgr.registerChecker<PointerSortingChecker>();
+}
+
+bool ento::shouldRegisterPointerSortingChecker(const LangOptions &LO) {
+ return LO.CPlusPlus;
+}