mgrang updated this revision to Diff 188232.
mgrang set the repository for this revision to rC Clang.

Repository:
  rC Clang

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D50488/new/

https://reviews.llvm.org/D50488

Files:
  docs/analyzer/checkers.rst
  include/clang/StaticAnalyzer/Checkers/Checkers.td
  lib/StaticAnalyzer/Checkers/CMakeLists.txt
  lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp
  test/Analysis/ptr-sort.cpp
  www/analyzer/alpha_checks.html

Index: www/analyzer/alpha_checks.html
===================================================================
--- www/analyzer/alpha_checks.html
+++ www/analyzer/alpha_checks.html
@@ -33,6 +33,7 @@
 <li><a href="#osx_alpha_checkers">OS X Alpha Checkers</a></li>
 <li><a href="#security_alpha_checkers">Security Alpha Checkers</a></li>
 <li><a href="#unix_alpha_checkers">Unix Alpha Checkers</a></li>
+<li><a href="#nondeterminism_alpha_checkers">Non-determinism Alpha Checkers</a></li>
 </ul>
 
 <!-- ============================= clone alpha ============================= -->
@@ -1174,6 +1175,28 @@
 
 </tbody></table>
 
+<!-- =========================== nondeterminism alpha =========================== -->
+<h3 id="nondeterminism_alpha_checkers">Non-determinism Alpha Checkers</h3>
+<table class="checkers">
+<colgroup><col class="namedescr"><col class="example"></colgroup>
+<thead><tr><td>Name, Description</td><td>Example</td></tr></thead>
+
+<tbody>
+<tr><td><a id="alpha.nondeterminism.PointerSorting"><div class="namedescr expandable"><span class="name">
+alpha.nondeterminism.PointerSorting</span><span class="lang">
+(C++)</span><div class="descr">
+Check for non-determinism caused by sorting of pointers.</div></div></a></td>
+<td><div class="exampleContainer expandable">
+<div class="example"><pre>
+// C++
+void test() {
+ int a = 1, b = 2;
+ std::vector<int *> V = {&a, &b};
+ std::sort(V.begin(), V.end()); // warn
+}
+</pre></div></div></td></tr>
+</tbody></table>
+
 </div> <!-- page -->
 </div> <!-- content -->
 </body>
Index: test/Analysis/ptr-sort.cpp
===================================================================
--- /dev/null
+++ test/Analysis/ptr-sort.cpp
@@ -0,0 +1,57 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,alpha.nondeterminism.PointerSorting %s -analyzer-output=text -verify
+
+#include "Inputs/system-header-simulator-cxx.h"
+namespace std {
+  template<class ForwardIt>
+  bool is_sorted(ForwardIt first, ForwardIt last);
+
+  template <class RandomIt>
+  void nth_element(RandomIt first, RandomIt nth, RandomIt last);
+
+  template<class RandomIt>
+  void partial_sort(RandomIt first, RandomIt middle, RandomIt last);
+
+  template<class RandomIt>
+  void sort (RandomIt first, RandomIt last);
+
+  template<class RandomIt>
+  void stable_sort(RandomIt first, RandomIt last);
+
+  template<class BidirIt, class UnaryPredicate>
+  BidirIt partition(BidirIt first, BidirIt last, UnaryPredicate p);
+
+  template<class BidirIt, class UnaryPredicate>
+  BidirIt stable_partition(BidirIt first, BidirIt last, UnaryPredicate p);
+}
+
+bool f (int x) { return true; }
+bool g (int *x) { return true; }
+
+void PointerSorting() {
+  int a = 1, b = 2, c = 3;
+  std::vector<int> V1 = {a, b};
+  std::vector<int *> V2 = {&a, &b};
+
+  std::is_sorted(V1.begin(), V1.end());                    // no-warning
+  std::nth_element(V1.begin(), V1.begin() + 1, V1.end());  // no-warning
+  std::partial_sort(V1.begin(), V1.begin() + 1, V1.end()); // no-warning
+  std::sort(V1.begin(), V1.end());                         // no-warning
+  std::stable_sort(V1.begin(), V1.end());                  // no-warning
+  std::partition(V1.begin(), V1.end(), f);                 // no-warning
+  std::stable_partition(V1.begin(), V1.end(), g);          // no-warning
+
+  std::is_sorted(V2.begin(), V2.end()); // expected-warning {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  // expected-note@-1 {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  std::nth_element(V2.begin(), V2.begin() + 1, V2.end()); // expected-warning {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  // expected-note@-1 {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  std::partial_sort(V2.begin(), V2.begin() + 1, V2.end()); // expected-warning {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  // expected-note@-1 {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  std::sort(V2.begin(), V2.end()); // expected-warning {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  // expected-note@-1 {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  std::stable_sort(V2.begin(), V2.end()); // expected-warning {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  // expected-note@-1 {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  std::partition(V2.begin(), V2.end(), f); // expected-warning {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  // expected-note@-1 {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  std::stable_partition(V2.begin(), V2.end(), g); // expected-warning {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+  // expected-note@-1 {{Sorting pointer-like elements can result in non-deterministic ordering}} [alpha.nondeterminism.PointerSorting]
+}
Index: lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp
===================================================================
--- /dev/null
+++ lib/StaticAnalyzer/Checkers/PointerSortingChecker.cpp
@@ -0,0 +1,114 @@
+//=== PointerSortingChecker.cpp - Pointer sorting checker ------*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// 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;
+}
Index: lib/StaticAnalyzer/Checkers/CMakeLists.txt
===================================================================
--- lib/StaticAnalyzer/Checkers/CMakeLists.txt
+++ lib/StaticAnalyzer/Checkers/CMakeLists.txt
@@ -74,6 +74,7 @@
   OSObjectCStyleCast.cpp
   PaddingChecker.cpp
   PointerArithChecker.cpp
+  PointerSortingChecker.cpp
   PointerSubChecker.cpp
   PthreadLockChecker.cpp
   RetainCountChecker/RetainCountChecker.cpp
Index: include/clang/StaticAnalyzer/Checkers/Checkers.td
===================================================================
--- include/clang/StaticAnalyzer/Checkers/Checkers.td
+++ include/clang/StaticAnalyzer/Checkers/Checkers.td
@@ -94,6 +94,8 @@
 
 def CloneDetectionAlpha : Package<"clone">, ParentPackage<Alpha>;
 
+def NonDeterminismAlpha : Package<"nondeterminism">, ParentPackage<Alpha>;
+
 //===----------------------------------------------------------------------===//
 // Core Checkers.
 //===----------------------------------------------------------------------===//
@@ -1038,3 +1040,15 @@
   Documentation<NotDocumented>;
 
 } // end optin.portability
+
+//===----------------------------------------------------------------------===//
+// NonDeterminism checkers.
+//===----------------------------------------------------------------------===//
+
+let ParentPackage = NonDeterminismAlpha in {
+
+def PointerSortingChecker : Checker<"PointerSorting">,
+  HelpText<"Check for non-determinism caused by sorting of pointers">,
+  Documentation<HasDocumentation>;
+
+} // end alpha.nondeterminism
Index: docs/analyzer/checkers.rst
===================================================================
--- docs/analyzer/checkers.rst
+++ docs/analyzer/checkers.rst
@@ -1943,6 +1943,18 @@
    int y = strlen((char *)&test); // warn
  }
 
+alpha.nondeterminism.PointerSorting (C++)
+"""""""""""""""""""""""""
+Check for non-determinism caused by sorting of pointers.
+
+.. code-block:: c
+
+ void test() {
+  int a = 1, b = 2;
+  std::vector<int *> V = {&a, &b};
+  std::sort(V.begin(), V.end()); // warn
+ }
+
 
 Debug Checkers
 ---------------
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