1 //== BasicObjCFoundationChecks.cpp - Simple Apple-Foundation checks -*- C++ -*--
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines BasicObjCFoundationChecks, a class that encapsulates
11 // a set of simple checks to run on Objective-C code using Apple's Foundation
14 //===----------------------------------------------------------------------===//
16 #include "ClangSACheckers.h"
17 #include "SelectorExtras.h"
18 #include "clang/AST/ASTContext.h"
19 #include "clang/AST/DeclObjC.h"
20 #include "clang/AST/Expr.h"
21 #include "clang/AST/ExprObjC.h"
22 #include "clang/AST/StmtObjC.h"
23 #include "clang/Analysis/DomainSpecific/CocoaConventions.h"
24 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
25 #include "clang/StaticAnalyzer/Core/Checker.h"
26 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
27 #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
28 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
29 #include "clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h"
30 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
31 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
32 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
33 #include "llvm/ADT/SmallString.h"
34 #include "llvm/ADT/StringMap.h"
35 #include "llvm/Support/raw_ostream.h"
37 using namespace clang;
41 class APIMisuse : public BugType {
43 APIMisuse(const CheckerBase *checker, const char *name)
44 : BugType(checker, name, "API Misuse (Apple)") {}
46 } // end anonymous namespace
48 //===----------------------------------------------------------------------===//
50 //===----------------------------------------------------------------------===//
52 static StringRef GetReceiverInterfaceName(const ObjCMethodCall &msg) {
53 if (const ObjCInterfaceDecl *ID = msg.getReceiverInterface())
54 return ID->getIdentifier()->getName();
58 enum FoundationClass {
69 static FoundationClass findKnownClass(const ObjCInterfaceDecl *ID,
70 bool IncludeSuperclasses = true) {
71 static llvm::StringMap<FoundationClass> Classes;
72 if (Classes.empty()) {
73 Classes["NSArray"] = FC_NSArray;
74 Classes["NSDictionary"] = FC_NSDictionary;
75 Classes["NSEnumerator"] = FC_NSEnumerator;
76 Classes["NSNull"] = FC_NSNull;
77 Classes["NSOrderedSet"] = FC_NSOrderedSet;
78 Classes["NSSet"] = FC_NSSet;
79 Classes["NSString"] = FC_NSString;
82 // FIXME: Should we cache this at all?
83 FoundationClass result = Classes.lookup(ID->getIdentifier()->getName());
84 if (result == FC_None && IncludeSuperclasses)
85 if (const ObjCInterfaceDecl *Super = ID->getSuperClass())
86 return findKnownClass(Super);
91 //===----------------------------------------------------------------------===//
92 // NilArgChecker - Check for prohibited nil arguments to ObjC method calls.
93 //===----------------------------------------------------------------------===//
96 class NilArgChecker : public Checker<check::PreObjCMessage,
97 check::PostStmt<ObjCDictionaryLiteral>,
98 check::PostStmt<ObjCArrayLiteral> > {
99 mutable std::unique_ptr<APIMisuse> BT;
101 mutable llvm::SmallDenseMap<Selector, unsigned, 16> StringSelectors;
102 mutable Selector ArrayWithObjectSel;
103 mutable Selector AddObjectSel;
104 mutable Selector InsertObjectAtIndexSel;
105 mutable Selector ReplaceObjectAtIndexWithObjectSel;
106 mutable Selector SetObjectAtIndexedSubscriptSel;
107 mutable Selector ArrayByAddingObjectSel;
108 mutable Selector DictionaryWithObjectForKeySel;
109 mutable Selector SetObjectForKeySel;
110 mutable Selector SetObjectForKeyedSubscriptSel;
111 mutable Selector RemoveObjectForKeySel;
113 void warnIfNilExpr(const Expr *E,
115 CheckerContext &C) const;
117 void warnIfNilArg(CheckerContext &C,
118 const ObjCMethodCall &msg, unsigned Arg,
119 FoundationClass Class,
120 bool CanBeSubscript = false) const;
122 void generateBugReport(ExplodedNode *N,
126 CheckerContext &C) const;
129 void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
130 void checkPostStmt(const ObjCDictionaryLiteral *DL,
131 CheckerContext &C) const;
132 void checkPostStmt(const ObjCArrayLiteral *AL,
133 CheckerContext &C) const;
135 } // end anonymous namespace
137 void NilArgChecker::warnIfNilExpr(const Expr *E,
139 CheckerContext &C) const {
140 ProgramStateRef State = C.getState();
141 if (State->isNull(C.getSVal(E)).isConstrainedTrue()) {
143 if (ExplodedNode *N = C.generateErrorNode()) {
144 generateBugReport(N, Msg, E->getSourceRange(), E, C);
149 void NilArgChecker::warnIfNilArg(CheckerContext &C,
150 const ObjCMethodCall &msg,
152 FoundationClass Class,
153 bool CanBeSubscript) const {
154 // Check if the argument is nil.
155 ProgramStateRef State = C.getState();
156 if (!State->isNull(msg.getArgSVal(Arg)).isConstrainedTrue())
159 if (ExplodedNode *N = C.generateErrorNode()) {
160 SmallString<128> sbuf;
161 llvm::raw_svector_ostream os(sbuf);
163 if (CanBeSubscript && msg.getMessageKind() == OCM_Subscript) {
165 if (Class == FC_NSArray) {
166 os << "Array element cannot be nil";
167 } else if (Class == FC_NSDictionary) {
169 os << "Value stored into '";
170 os << GetReceiverInterfaceName(msg) << "' cannot be nil";
173 os << "'"<< GetReceiverInterfaceName(msg) << "' key cannot be nil";
176 llvm_unreachable("Missing foundation class for the subscript expr");
179 if (Class == FC_NSDictionary) {
181 os << "Value argument ";
184 os << "Key argument ";
187 msg.getSelector().print(os);
188 os << "' cannot be nil";
190 os << "Argument to '" << GetReceiverInterfaceName(msg) << "' method '";
191 msg.getSelector().print(os);
192 os << "' cannot be nil";
196 generateBugReport(N, os.str(), msg.getArgSourceRange(Arg),
197 msg.getArgExpr(Arg), C);
201 void NilArgChecker::generateBugReport(ExplodedNode *N,
205 CheckerContext &C) const {
207 BT.reset(new APIMisuse(this, "nil argument"));
209 auto R = llvm::make_unique<BugReport>(*BT, Msg, N);
211 bugreporter::trackNullOrUndefValue(N, E, *R);
212 C.emitReport(std::move(R));
215 void NilArgChecker::checkPreObjCMessage(const ObjCMethodCall &msg,
216 CheckerContext &C) const {
217 const ObjCInterfaceDecl *ID = msg.getReceiverInterface();
221 FoundationClass Class = findKnownClass(ID);
223 static const unsigned InvalidArgIndex = UINT_MAX;
224 unsigned Arg = InvalidArgIndex;
225 bool CanBeSubscript = false;
227 if (Class == FC_NSString) {
228 Selector S = msg.getSelector();
230 if (S.isUnarySelector())
233 if (StringSelectors.empty()) {
234 ASTContext &Ctx = C.getASTContext();
236 getKeywordSelector(Ctx, "caseInsensitiveCompare", nullptr),
237 getKeywordSelector(Ctx, "compare", nullptr),
238 getKeywordSelector(Ctx, "compare", "options", nullptr),
239 getKeywordSelector(Ctx, "compare", "options", "range", nullptr),
240 getKeywordSelector(Ctx, "compare", "options", "range", "locale",
242 getKeywordSelector(Ctx, "componentsSeparatedByCharactersInSet",
244 getKeywordSelector(Ctx, "initWithFormat",
246 getKeywordSelector(Ctx, "localizedCaseInsensitiveCompare", nullptr),
247 getKeywordSelector(Ctx, "localizedCompare", nullptr),
248 getKeywordSelector(Ctx, "localizedStandardCompare", nullptr),
250 for (Selector KnownSel : Sels)
251 StringSelectors[KnownSel] = 0;
253 auto I = StringSelectors.find(S);
254 if (I == StringSelectors.end())
257 } else if (Class == FC_NSArray) {
258 Selector S = msg.getSelector();
260 if (S.isUnarySelector())
263 if (ArrayWithObjectSel.isNull()) {
264 ASTContext &Ctx = C.getASTContext();
265 ArrayWithObjectSel = getKeywordSelector(Ctx, "arrayWithObject", nullptr);
266 AddObjectSel = getKeywordSelector(Ctx, "addObject", nullptr);
267 InsertObjectAtIndexSel =
268 getKeywordSelector(Ctx, "insertObject", "atIndex", nullptr);
269 ReplaceObjectAtIndexWithObjectSel =
270 getKeywordSelector(Ctx, "replaceObjectAtIndex", "withObject", nullptr);
271 SetObjectAtIndexedSubscriptSel =
272 getKeywordSelector(Ctx, "setObject", "atIndexedSubscript", nullptr);
273 ArrayByAddingObjectSel =
274 getKeywordSelector(Ctx, "arrayByAddingObject", nullptr);
277 if (S == ArrayWithObjectSel || S == AddObjectSel ||
278 S == InsertObjectAtIndexSel || S == ArrayByAddingObjectSel) {
280 } else if (S == SetObjectAtIndexedSubscriptSel) {
282 CanBeSubscript = true;
283 } else if (S == ReplaceObjectAtIndexWithObjectSel) {
286 } else if (Class == FC_NSDictionary) {
287 Selector S = msg.getSelector();
289 if (S.isUnarySelector())
292 if (DictionaryWithObjectForKeySel.isNull()) {
293 ASTContext &Ctx = C.getASTContext();
294 DictionaryWithObjectForKeySel =
295 getKeywordSelector(Ctx, "dictionaryWithObject", "forKey", nullptr);
297 getKeywordSelector(Ctx, "setObject", "forKey", nullptr);
298 SetObjectForKeyedSubscriptSel =
299 getKeywordSelector(Ctx, "setObject", "forKeyedSubscript", nullptr);
300 RemoveObjectForKeySel =
301 getKeywordSelector(Ctx, "removeObjectForKey", nullptr);
304 if (S == DictionaryWithObjectForKeySel || S == SetObjectForKeySel) {
306 warnIfNilArg(C, msg, /* Arg */1, Class);
307 } else if (S == SetObjectForKeyedSubscriptSel) {
308 CanBeSubscript = true;
310 } else if (S == RemoveObjectForKeySel) {
315 // If argument is '0', report a warning.
316 if ((Arg != InvalidArgIndex))
317 warnIfNilArg(C, msg, Arg, Class, CanBeSubscript);
320 void NilArgChecker::checkPostStmt(const ObjCArrayLiteral *AL,
321 CheckerContext &C) const {
322 unsigned NumOfElements = AL->getNumElements();
323 for (unsigned i = 0; i < NumOfElements; ++i) {
324 warnIfNilExpr(AL->getElement(i), "Array element cannot be nil", C);
328 void NilArgChecker::checkPostStmt(const ObjCDictionaryLiteral *DL,
329 CheckerContext &C) const {
330 unsigned NumOfElements = DL->getNumElements();
331 for (unsigned i = 0; i < NumOfElements; ++i) {
332 ObjCDictionaryElement Element = DL->getKeyValueElement(i);
333 warnIfNilExpr(Element.Key, "Dictionary key cannot be nil", C);
334 warnIfNilExpr(Element.Value, "Dictionary value cannot be nil", C);
338 //===----------------------------------------------------------------------===//
340 //===----------------------------------------------------------------------===//
343 class CFNumberCreateChecker : public Checker< check::PreStmt<CallExpr> > {
344 mutable std::unique_ptr<APIMisuse> BT;
345 mutable IdentifierInfo* II;
347 CFNumberCreateChecker() : II(nullptr) {}
349 void checkPreStmt(const CallExpr *CE, CheckerContext &C) const;
352 void EmitError(const TypedRegion* R, const Expr *Ex,
353 uint64_t SourceSize, uint64_t TargetSize, uint64_t NumberKind);
355 } // end anonymous namespace
358 kCFNumberSInt8Type = 1,
359 kCFNumberSInt16Type = 2,
360 kCFNumberSInt32Type = 3,
361 kCFNumberSInt64Type = 4,
362 kCFNumberFloat32Type = 5,
363 kCFNumberFloat64Type = 6,
364 kCFNumberCharType = 7,
365 kCFNumberShortType = 8,
366 kCFNumberIntType = 9,
367 kCFNumberLongType = 10,
368 kCFNumberLongLongType = 11,
369 kCFNumberFloatType = 12,
370 kCFNumberDoubleType = 13,
371 kCFNumberCFIndexType = 14,
372 kCFNumberNSIntegerType = 15,
373 kCFNumberCGFloatType = 16
376 static Optional<uint64_t> GetCFNumberSize(ASTContext &Ctx, uint64_t i) {
377 static const unsigned char FixedSize[] = { 8, 16, 32, 64, 32, 64 };
379 if (i < kCFNumberCharType)
380 return FixedSize[i-1];
385 case kCFNumberCharType: T = Ctx.CharTy; break;
386 case kCFNumberShortType: T = Ctx.ShortTy; break;
387 case kCFNumberIntType: T = Ctx.IntTy; break;
388 case kCFNumberLongType: T = Ctx.LongTy; break;
389 case kCFNumberLongLongType: T = Ctx.LongLongTy; break;
390 case kCFNumberFloatType: T = Ctx.FloatTy; break;
391 case kCFNumberDoubleType: T = Ctx.DoubleTy; break;
392 case kCFNumberCFIndexType:
393 case kCFNumberNSIntegerType:
394 case kCFNumberCGFloatType:
395 // FIXME: We need a way to map from names to Type*.
400 return Ctx.getTypeSize(T);
404 static const char* GetCFNumberTypeStr(uint64_t i) {
405 static const char* Names[] = {
406 "kCFNumberSInt8Type",
407 "kCFNumberSInt16Type",
408 "kCFNumberSInt32Type",
409 "kCFNumberSInt64Type",
410 "kCFNumberFloat32Type",
411 "kCFNumberFloat64Type",
413 "kCFNumberShortType",
416 "kCFNumberLongLongType",
417 "kCFNumberFloatType",
418 "kCFNumberDoubleType",
419 "kCFNumberCFIndexType",
420 "kCFNumberNSIntegerType",
421 "kCFNumberCGFloatType"
424 return i <= kCFNumberCGFloatType ? Names[i-1] : "Invalid CFNumberType";
428 void CFNumberCreateChecker::checkPreStmt(const CallExpr *CE,
429 CheckerContext &C) const {
430 ProgramStateRef state = C.getState();
431 const FunctionDecl *FD = C.getCalleeDecl(CE);
435 ASTContext &Ctx = C.getASTContext();
437 II = &Ctx.Idents.get("CFNumberCreate");
439 if (FD->getIdentifier() != II || CE->getNumArgs() != 3)
442 // Get the value of the "theType" argument.
443 const LocationContext *LCtx = C.getLocationContext();
444 SVal TheTypeVal = state->getSVal(CE->getArg(1), LCtx);
446 // FIXME: We really should allow ranges of valid theType values, and
447 // bifurcate the state appropriately.
448 Optional<nonloc::ConcreteInt> V = TheTypeVal.getAs<nonloc::ConcreteInt>();
452 uint64_t NumberKind = V->getValue().getLimitedValue();
453 Optional<uint64_t> OptTargetSize = GetCFNumberSize(Ctx, NumberKind);
455 // FIXME: In some cases we can emit an error.
459 uint64_t TargetSize = *OptTargetSize;
461 // Look at the value of the integer being passed by reference. Essentially
462 // we want to catch cases where the value passed in is not equal to the
463 // size of the type being created.
464 SVal TheValueExpr = state->getSVal(CE->getArg(2), LCtx);
466 // FIXME: Eventually we should handle arbitrary locations. We can do this
467 // by having an enhanced memory model that does low-level typing.
468 Optional<loc::MemRegionVal> LV = TheValueExpr.getAs<loc::MemRegionVal>();
472 const TypedValueRegion* R = dyn_cast<TypedValueRegion>(LV->stripCasts());
476 QualType T = Ctx.getCanonicalType(R->getValueType());
478 // FIXME: If the pointee isn't an integer type, should we flag a warning?
479 // People can do weird stuff with pointers.
481 if (!T->isIntegralOrEnumerationType())
484 uint64_t SourceSize = Ctx.getTypeSize(T);
486 // CHECK: is SourceSize == TargetSize
487 if (SourceSize == TargetSize)
490 // Generate an error. Only generate a sink error node
491 // if 'SourceSize < TargetSize'; otherwise generate a non-fatal error node.
493 // FIXME: We can actually create an abstract "CFNumber" object that has
494 // the bits initialized to the provided values.
496 ExplodedNode *N = SourceSize < TargetSize ? C.generateErrorNode()
497 : C.generateNonFatalErrorNode();
499 SmallString<128> sbuf;
500 llvm::raw_svector_ostream os(sbuf);
502 os << (SourceSize == 8 ? "An " : "A ")
503 << SourceSize << " bit integer is used to initialize a CFNumber "
504 "object that represents "
505 << (TargetSize == 8 ? "an " : "a ")
506 << TargetSize << " bit integer. ";
508 if (SourceSize < TargetSize)
509 os << (TargetSize - SourceSize)
510 << " bits of the CFNumber value will be garbage." ;
512 os << (SourceSize - TargetSize)
513 << " bits of the input integer will be lost.";
516 BT.reset(new APIMisuse(this, "Bad use of CFNumberCreate"));
518 auto report = llvm::make_unique<BugReport>(*BT, os.str(), N);
519 report->addRange(CE->getArg(2)->getSourceRange());
520 C.emitReport(std::move(report));
524 //===----------------------------------------------------------------------===//
525 // CFRetain/CFRelease/CFMakeCollectable/CFAutorelease checking for null arguments.
526 //===----------------------------------------------------------------------===//
529 class CFRetainReleaseChecker : public Checker< check::PreStmt<CallExpr> > {
530 mutable std::unique_ptr<APIMisuse> BT;
531 mutable IdentifierInfo *Retain, *Release, *MakeCollectable, *Autorelease;
534 CFRetainReleaseChecker()
535 : Retain(nullptr), Release(nullptr), MakeCollectable(nullptr),
536 Autorelease(nullptr) {}
537 void checkPreStmt(const CallExpr *CE, CheckerContext &C) const;
539 } // end anonymous namespace
541 void CFRetainReleaseChecker::checkPreStmt(const CallExpr *CE,
542 CheckerContext &C) const {
543 // If the CallExpr doesn't have exactly 1 argument just give up checking.
544 if (CE->getNumArgs() != 1)
547 ProgramStateRef state = C.getState();
548 const FunctionDecl *FD = C.getCalleeDecl(CE);
553 ASTContext &Ctx = C.getASTContext();
554 Retain = &Ctx.Idents.get("CFRetain");
555 Release = &Ctx.Idents.get("CFRelease");
556 MakeCollectable = &Ctx.Idents.get("CFMakeCollectable");
557 Autorelease = &Ctx.Idents.get("CFAutorelease");
558 BT.reset(new APIMisuse(
559 this, "null passed to CF memory management function"));
562 // Check if we called CFRetain/CFRelease/CFMakeCollectable/CFAutorelease.
563 const IdentifierInfo *FuncII = FD->getIdentifier();
564 if (!(FuncII == Retain || FuncII == Release || FuncII == MakeCollectable ||
565 FuncII == Autorelease))
568 // FIXME: The rest of this just checks that the argument is non-null.
569 // It should probably be refactored and combined with NonNullParamChecker.
571 // Get the argument's value.
572 const Expr *Arg = CE->getArg(0);
573 SVal ArgVal = state->getSVal(Arg, C.getLocationContext());
574 Optional<DefinedSVal> DefArgVal = ArgVal.getAs<DefinedSVal>();
579 SValBuilder &svalBuilder = C.getSValBuilder();
581 svalBuilder.makeZeroVal(Arg->getType()).castAs<DefinedSVal>();
583 // Make an expression asserting that they're equal.
584 DefinedOrUnknownSVal ArgIsNull = svalBuilder.evalEQ(state, zero, *DefArgVal);
587 ProgramStateRef stateTrue, stateFalse;
588 std::tie(stateTrue, stateFalse) = state->assume(ArgIsNull);
590 if (stateTrue && !stateFalse) {
591 ExplodedNode *N = C.generateErrorNode(stateTrue);
595 const char *description;
596 if (FuncII == Retain)
597 description = "Null pointer argument in call to CFRetain";
598 else if (FuncII == Release)
599 description = "Null pointer argument in call to CFRelease";
600 else if (FuncII == MakeCollectable)
601 description = "Null pointer argument in call to CFMakeCollectable";
602 else if (FuncII == Autorelease)
603 description = "Null pointer argument in call to CFAutorelease";
605 llvm_unreachable("impossible case");
607 auto report = llvm::make_unique<BugReport>(*BT, description, N);
608 report->addRange(Arg->getSourceRange());
609 bugreporter::trackNullOrUndefValue(N, Arg, *report);
610 C.emitReport(std::move(report));
614 // From here on, we know the argument is non-null.
615 C.addTransition(stateFalse);
618 //===----------------------------------------------------------------------===//
619 // Check for sending 'retain', 'release', or 'autorelease' directly to a Class.
620 //===----------------------------------------------------------------------===//
623 class ClassReleaseChecker : public Checker<check::PreObjCMessage> {
624 mutable Selector releaseS;
625 mutable Selector retainS;
626 mutable Selector autoreleaseS;
627 mutable Selector drainS;
628 mutable std::unique_ptr<BugType> BT;
631 void checkPreObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
633 } // end anonymous namespace
635 void ClassReleaseChecker::checkPreObjCMessage(const ObjCMethodCall &msg,
636 CheckerContext &C) const {
638 BT.reset(new APIMisuse(
639 this, "message incorrectly sent to class instead of class instance"));
641 ASTContext &Ctx = C.getASTContext();
642 releaseS = GetNullarySelector("release", Ctx);
643 retainS = GetNullarySelector("retain", Ctx);
644 autoreleaseS = GetNullarySelector("autorelease", Ctx);
645 drainS = GetNullarySelector("drain", Ctx);
648 if (msg.isInstanceMessage())
650 const ObjCInterfaceDecl *Class = msg.getReceiverInterface();
653 Selector S = msg.getSelector();
654 if (!(S == releaseS || S == retainS || S == autoreleaseS || S == drainS))
657 if (ExplodedNode *N = C.generateNonFatalErrorNode()) {
658 SmallString<200> buf;
659 llvm::raw_svector_ostream os(buf);
663 os << "' message should be sent to instances "
664 "of class '" << Class->getName()
665 << "' and not the class directly";
667 auto report = llvm::make_unique<BugReport>(*BT, os.str(), N);
668 report->addRange(msg.getSourceRange());
669 C.emitReport(std::move(report));
673 //===----------------------------------------------------------------------===//
674 // Check for passing non-Objective-C types to variadic methods that expect
675 // only Objective-C types.
676 //===----------------------------------------------------------------------===//
679 class VariadicMethodTypeChecker : public Checker<check::PreObjCMessage> {
680 mutable Selector arrayWithObjectsS;
681 mutable Selector dictionaryWithObjectsAndKeysS;
682 mutable Selector setWithObjectsS;
683 mutable Selector orderedSetWithObjectsS;
684 mutable Selector initWithObjectsS;
685 mutable Selector initWithObjectsAndKeysS;
686 mutable std::unique_ptr<BugType> BT;
688 bool isVariadicMessage(const ObjCMethodCall &msg) const;
691 void checkPreObjCMessage(const ObjCMethodCall &msg, CheckerContext &C) const;
693 } // end anonymous namespace
695 /// isVariadicMessage - Returns whether the given message is a variadic message,
696 /// where all arguments must be Objective-C types.
698 VariadicMethodTypeChecker::isVariadicMessage(const ObjCMethodCall &msg) const {
699 const ObjCMethodDecl *MD = msg.getDecl();
701 if (!MD || !MD->isVariadic() || isa<ObjCProtocolDecl>(MD->getDeclContext()))
704 Selector S = msg.getSelector();
706 if (msg.isInstanceMessage()) {
707 // FIXME: Ideally we'd look at the receiver interface here, but that's not
708 // useful for init, because alloc returns 'id'. In theory, this could lead
709 // to false positives, for example if there existed a class that had an
710 // initWithObjects: implementation that does accept non-Objective-C pointer
711 // types, but the chance of that happening is pretty small compared to the
712 // gains that this analysis gives.
713 const ObjCInterfaceDecl *Class = MD->getClassInterface();
715 switch (findKnownClass(Class)) {
717 case FC_NSOrderedSet:
719 return S == initWithObjectsS;
720 case FC_NSDictionary:
721 return S == initWithObjectsAndKeysS;
726 const ObjCInterfaceDecl *Class = msg.getReceiverInterface();
728 switch (findKnownClass(Class)) {
730 return S == arrayWithObjectsS;
731 case FC_NSOrderedSet:
732 return S == orderedSetWithObjectsS;
734 return S == setWithObjectsS;
735 case FC_NSDictionary:
736 return S == dictionaryWithObjectsAndKeysS;
743 void VariadicMethodTypeChecker::checkPreObjCMessage(const ObjCMethodCall &msg,
744 CheckerContext &C) const {
746 BT.reset(new APIMisuse(this,
747 "Arguments passed to variadic method aren't all "
748 "Objective-C pointer types"));
750 ASTContext &Ctx = C.getASTContext();
751 arrayWithObjectsS = GetUnarySelector("arrayWithObjects", Ctx);
752 dictionaryWithObjectsAndKeysS =
753 GetUnarySelector("dictionaryWithObjectsAndKeys", Ctx);
754 setWithObjectsS = GetUnarySelector("setWithObjects", Ctx);
755 orderedSetWithObjectsS = GetUnarySelector("orderedSetWithObjects", Ctx);
757 initWithObjectsS = GetUnarySelector("initWithObjects", Ctx);
758 initWithObjectsAndKeysS = GetUnarySelector("initWithObjectsAndKeys", Ctx);
761 if (!isVariadicMessage(msg))
764 // We are not interested in the selector arguments since they have
765 // well-defined types, so the compiler will issue a warning for them.
766 unsigned variadicArgsBegin = msg.getSelector().getNumArgs();
768 // We're not interested in the last argument since it has to be nil or the
769 // compiler would have issued a warning for it elsewhere.
770 unsigned variadicArgsEnd = msg.getNumArgs() - 1;
772 if (variadicArgsEnd <= variadicArgsBegin)
775 // Verify that all arguments have Objective-C types.
776 Optional<ExplodedNode*> errorNode;
778 for (unsigned I = variadicArgsBegin; I != variadicArgsEnd; ++I) {
779 QualType ArgTy = msg.getArgExpr(I)->getType();
780 if (ArgTy->isObjCObjectPointerType())
783 // Block pointers are treaded as Objective-C pointers.
784 if (ArgTy->isBlockPointerType())
787 // Ignore pointer constants.
788 if (msg.getArgSVal(I).getAs<loc::ConcreteInt>())
791 // Ignore pointer types annotated with 'NSObject' attribute.
792 if (C.getASTContext().isObjCNSObjectType(ArgTy))
795 // Ignore CF references, which can be toll-free bridged.
796 if (coreFoundation::isCFObjectRef(ArgTy))
799 // Generate only one error node to use for all bug reports.
800 if (!errorNode.hasValue())
801 errorNode = C.generateNonFatalErrorNode();
803 if (!errorNode.getValue())
806 SmallString<128> sbuf;
807 llvm::raw_svector_ostream os(sbuf);
809 StringRef TypeName = GetReceiverInterfaceName(msg);
810 if (!TypeName.empty())
811 os << "Argument to '" << TypeName << "' method '";
813 os << "Argument to method '";
815 msg.getSelector().print(os);
816 os << "' should be an Objective-C pointer type, not '";
817 ArgTy.print(os, C.getLangOpts());
820 auto R = llvm::make_unique<BugReport>(*BT, os.str(), errorNode.getValue());
821 R->addRange(msg.getArgSourceRange(I));
822 C.emitReport(std::move(R));
826 //===----------------------------------------------------------------------===//
827 // Improves the modeling of loops over Cocoa collections.
828 //===----------------------------------------------------------------------===//
830 // The map from container symbol to the container count symbol.
831 // We currently will remember the last countainer count symbol encountered.
832 REGISTER_MAP_WITH_PROGRAMSTATE(ContainerCountMap, SymbolRef, SymbolRef)
833 REGISTER_MAP_WITH_PROGRAMSTATE(ContainerNonEmptyMap, SymbolRef, bool)
836 class ObjCLoopChecker
837 : public Checker<check::PostStmt<ObjCForCollectionStmt>,
838 check::PostObjCMessage,
840 check::PointerEscape > {
841 mutable IdentifierInfo *CountSelectorII;
843 bool isCollectionCountMethod(const ObjCMethodCall &M,
844 CheckerContext &C) const;
847 ObjCLoopChecker() : CountSelectorII(nullptr) {}
848 void checkPostStmt(const ObjCForCollectionStmt *FCS, CheckerContext &C) const;
849 void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
850 void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
851 ProgramStateRef checkPointerEscape(ProgramStateRef State,
852 const InvalidatedSymbols &Escaped,
853 const CallEvent *Call,
854 PointerEscapeKind Kind) const;
856 } // end anonymous namespace
858 static bool isKnownNonNilCollectionType(QualType T) {
859 const ObjCObjectPointerType *PT = T->getAs<ObjCObjectPointerType>();
863 const ObjCInterfaceDecl *ID = PT->getInterfaceDecl();
867 switch (findKnownClass(ID)) {
869 case FC_NSDictionary:
870 case FC_NSEnumerator:
871 case FC_NSOrderedSet:
879 /// Assumes that the collection is non-nil.
881 /// If the collection is known to be nil, returns NULL to indicate an infeasible
883 static ProgramStateRef checkCollectionNonNil(CheckerContext &C,
884 ProgramStateRef State,
885 const ObjCForCollectionStmt *FCS) {
889 SVal CollectionVal = C.getSVal(FCS->getCollection());
890 Optional<DefinedSVal> KnownCollection = CollectionVal.getAs<DefinedSVal>();
891 if (!KnownCollection)
894 ProgramStateRef StNonNil, StNil;
895 std::tie(StNonNil, StNil) = State->assume(*KnownCollection);
896 if (StNil && !StNonNil) {
897 // The collection is nil. This path is infeasible.
904 /// Assumes that the collection elements are non-nil.
906 /// This only applies if the collection is one of those known not to contain
908 static ProgramStateRef checkElementNonNil(CheckerContext &C,
909 ProgramStateRef State,
910 const ObjCForCollectionStmt *FCS) {
914 // See if the collection is one where we /know/ the elements are non-nil.
915 if (!isKnownNonNilCollectionType(FCS->getCollection()->getType()))
918 const LocationContext *LCtx = C.getLocationContext();
919 const Stmt *Element = FCS->getElement();
921 // FIXME: Copied from ExprEngineObjC.
922 Optional<Loc> ElementLoc;
923 if (const DeclStmt *DS = dyn_cast<DeclStmt>(Element)) {
924 const VarDecl *ElemDecl = cast<VarDecl>(DS->getSingleDecl());
925 assert(ElemDecl->getInit() == nullptr);
926 ElementLoc = State->getLValue(ElemDecl, LCtx);
928 ElementLoc = State->getSVal(Element, LCtx).getAs<Loc>();
934 // Go ahead and assume the value is non-nil.
935 SVal Val = State->getSVal(*ElementLoc);
936 return State->assume(Val.castAs<DefinedOrUnknownSVal>(), true);
939 /// Returns NULL state if the collection is known to contain elements
940 /// (or is known not to contain elements if the Assumption parameter is false.)
941 static ProgramStateRef
942 assumeCollectionNonEmpty(CheckerContext &C, ProgramStateRef State,
943 SymbolRef CollectionS, bool Assumption) {
944 if (!State || !CollectionS)
947 const SymbolRef *CountS = State->get<ContainerCountMap>(CollectionS);
949 const bool *KnownNonEmpty = State->get<ContainerNonEmptyMap>(CollectionS);
951 return State->set<ContainerNonEmptyMap>(CollectionS, Assumption);
952 return (Assumption == *KnownNonEmpty) ? State : nullptr;
955 SValBuilder &SvalBuilder = C.getSValBuilder();
956 SVal CountGreaterThanZeroVal =
957 SvalBuilder.evalBinOp(State, BO_GT,
958 nonloc::SymbolVal(*CountS),
959 SvalBuilder.makeIntVal(0, (*CountS)->getType()),
960 SvalBuilder.getConditionType());
961 Optional<DefinedSVal> CountGreaterThanZero =
962 CountGreaterThanZeroVal.getAs<DefinedSVal>();
963 if (!CountGreaterThanZero) {
964 // The SValBuilder cannot construct a valid SVal for this condition.
965 // This means we cannot properly reason about it.
969 return State->assume(*CountGreaterThanZero, Assumption);
972 static ProgramStateRef
973 assumeCollectionNonEmpty(CheckerContext &C, ProgramStateRef State,
974 const ObjCForCollectionStmt *FCS,
979 SymbolRef CollectionS =
980 State->getSVal(FCS->getCollection(), C.getLocationContext()).getAsSymbol();
981 return assumeCollectionNonEmpty(C, State, CollectionS, Assumption);
984 /// If the fist block edge is a back edge, we are reentering the loop.
985 static bool alreadyExecutedAtLeastOneLoopIteration(const ExplodedNode *N,
986 const ObjCForCollectionStmt *FCS) {
990 ProgramPoint P = N->getLocation();
991 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
992 return BE->getSrc()->getLoopTarget() == FCS;
995 // Keep looking for a block edge.
996 for (ExplodedNode::const_pred_iterator I = N->pred_begin(),
997 E = N->pred_end(); I != E; ++I) {
998 if (alreadyExecutedAtLeastOneLoopIteration(*I, FCS))
1005 void ObjCLoopChecker::checkPostStmt(const ObjCForCollectionStmt *FCS,
1006 CheckerContext &C) const {
1007 ProgramStateRef State = C.getState();
1009 // Check if this is the branch for the end of the loop.
1010 SVal CollectionSentinel = C.getSVal(FCS);
1011 if (CollectionSentinel.isZeroConstant()) {
1012 if (!alreadyExecutedAtLeastOneLoopIteration(C.getPredecessor(), FCS))
1013 State = assumeCollectionNonEmpty(C, State, FCS, /*Assumption*/false);
1015 // Otherwise, this is a branch that goes through the loop body.
1017 State = checkCollectionNonNil(C, State, FCS);
1018 State = checkElementNonNil(C, State, FCS);
1019 State = assumeCollectionNonEmpty(C, State, FCS, /*Assumption*/true);
1023 C.generateSink(C.getState(), C.getPredecessor());
1024 else if (State != C.getState())
1025 C.addTransition(State);
1028 bool ObjCLoopChecker::isCollectionCountMethod(const ObjCMethodCall &M,
1029 CheckerContext &C) const {
1030 Selector S = M.getSelector();
1031 // Initialize the identifiers on first use.
1032 if (!CountSelectorII)
1033 CountSelectorII = &C.getASTContext().Idents.get("count");
1035 // If the method returns collection count, record the value.
1036 return S.isUnarySelector() &&
1037 (S.getIdentifierInfoForSlot(0) == CountSelectorII);
1040 void ObjCLoopChecker::checkPostObjCMessage(const ObjCMethodCall &M,
1041 CheckerContext &C) const {
1042 if (!M.isInstanceMessage())
1045 const ObjCInterfaceDecl *ClassID = M.getReceiverInterface();
1049 FoundationClass Class = findKnownClass(ClassID);
1050 if (Class != FC_NSDictionary &&
1051 Class != FC_NSArray &&
1052 Class != FC_NSSet &&
1053 Class != FC_NSOrderedSet)
1056 SymbolRef ContainerS = M.getReceiverSVal().getAsSymbol();
1060 // If we are processing a call to "count", get the symbolic value returned by
1061 // a call to "count" and add it to the map.
1062 if (!isCollectionCountMethod(M, C))
1065 const Expr *MsgExpr = M.getOriginExpr();
1066 SymbolRef CountS = C.getSVal(MsgExpr).getAsSymbol();
1068 ProgramStateRef State = C.getState();
1070 C.getSymbolManager().addSymbolDependency(ContainerS, CountS);
1071 State = State->set<ContainerCountMap>(ContainerS, CountS);
1073 if (const bool *NonEmpty = State->get<ContainerNonEmptyMap>(ContainerS)) {
1074 State = State->remove<ContainerNonEmptyMap>(ContainerS);
1075 State = assumeCollectionNonEmpty(C, State, ContainerS, *NonEmpty);
1078 C.addTransition(State);
1082 static SymbolRef getMethodReceiverIfKnownImmutable(const CallEvent *Call) {
1083 const ObjCMethodCall *Message = dyn_cast_or_null<ObjCMethodCall>(Call);
1087 const ObjCMethodDecl *MD = Message->getDecl();
1091 const ObjCInterfaceDecl *StaticClass;
1092 if (isa<ObjCProtocolDecl>(MD->getDeclContext())) {
1093 // We can't find out where the method was declared without doing more work.
1094 // Instead, see if the receiver is statically typed as a known immutable
1096 StaticClass = Message->getOriginExpr()->getReceiverInterface();
1098 StaticClass = MD->getClassInterface();
1104 switch (findKnownClass(StaticClass, /*IncludeSuper=*/false)) {
1108 case FC_NSDictionary:
1109 case FC_NSEnumerator:
1111 case FC_NSOrderedSet:
1117 return Message->getReceiverSVal().getAsSymbol();
1121 ObjCLoopChecker::checkPointerEscape(ProgramStateRef State,
1122 const InvalidatedSymbols &Escaped,
1123 const CallEvent *Call,
1124 PointerEscapeKind Kind) const {
1125 SymbolRef ImmutableReceiver = getMethodReceiverIfKnownImmutable(Call);
1127 // Remove the invalidated symbols form the collection count map.
1128 for (InvalidatedSymbols::const_iterator I = Escaped.begin(),
1133 // Don't invalidate this symbol's count if we know the method being called
1134 // is declared on an immutable class. This isn't completely correct if the
1135 // receiver is also passed as an argument, but in most uses of NSArray,
1136 // NSDictionary, etc. this isn't likely to happen in a dangerous way.
1137 if (Sym == ImmutableReceiver)
1140 // The symbol escaped. Pessimistically, assume that the count could have
1142 State = State->remove<ContainerCountMap>(Sym);
1143 State = State->remove<ContainerNonEmptyMap>(Sym);
1148 void ObjCLoopChecker::checkDeadSymbols(SymbolReaper &SymReaper,
1149 CheckerContext &C) const {
1150 ProgramStateRef State = C.getState();
1152 // Remove the dead symbols from the collection count map.
1153 ContainerCountMapTy Tracked = State->get<ContainerCountMap>();
1154 for (ContainerCountMapTy::iterator I = Tracked.begin(),
1155 E = Tracked.end(); I != E; ++I) {
1156 SymbolRef Sym = I->first;
1157 if (SymReaper.isDead(Sym)) {
1158 State = State->remove<ContainerCountMap>(Sym);
1159 State = State->remove<ContainerNonEmptyMap>(Sym);
1163 C.addTransition(State);
1167 /// \class ObjCNonNilReturnValueChecker
1168 /// \brief The checker restricts the return values of APIs known to
1169 /// never (or almost never) return 'nil'.
1170 class ObjCNonNilReturnValueChecker
1171 : public Checker<check::PostObjCMessage,
1172 check::PostStmt<ObjCArrayLiteral>,
1173 check::PostStmt<ObjCDictionaryLiteral>,
1174 check::PostStmt<ObjCBoxedExpr> > {
1175 mutable bool Initialized;
1176 mutable Selector ObjectAtIndex;
1177 mutable Selector ObjectAtIndexedSubscript;
1178 mutable Selector NullSelector;
1181 ObjCNonNilReturnValueChecker() : Initialized(false) {}
1183 ProgramStateRef assumeExprIsNonNull(const Expr *NonNullExpr,
1184 ProgramStateRef State,
1185 CheckerContext &C) const;
1186 void assumeExprIsNonNull(const Expr *E, CheckerContext &C) const {
1187 C.addTransition(assumeExprIsNonNull(E, C.getState(), C));
1190 void checkPostStmt(const ObjCArrayLiteral *E, CheckerContext &C) const {
1191 assumeExprIsNonNull(E, C);
1193 void checkPostStmt(const ObjCDictionaryLiteral *E, CheckerContext &C) const {
1194 assumeExprIsNonNull(E, C);
1196 void checkPostStmt(const ObjCBoxedExpr *E, CheckerContext &C) const {
1197 assumeExprIsNonNull(E, C);
1200 void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
1202 } // end anonymous namespace
1205 ObjCNonNilReturnValueChecker::assumeExprIsNonNull(const Expr *NonNullExpr,
1206 ProgramStateRef State,
1207 CheckerContext &C) const {
1208 SVal Val = State->getSVal(NonNullExpr, C.getLocationContext());
1209 if (Optional<DefinedOrUnknownSVal> DV = Val.getAs<DefinedOrUnknownSVal>())
1210 return State->assume(*DV, true);
1214 void ObjCNonNilReturnValueChecker::checkPostObjCMessage(const ObjCMethodCall &M,
1217 ProgramStateRef State = C.getState();
1220 ASTContext &Ctx = C.getASTContext();
1221 ObjectAtIndex = GetUnarySelector("objectAtIndex", Ctx);
1222 ObjectAtIndexedSubscript = GetUnarySelector("objectAtIndexedSubscript", Ctx);
1223 NullSelector = GetNullarySelector("null", Ctx);
1226 // Check the receiver type.
1227 if (const ObjCInterfaceDecl *Interface = M.getReceiverInterface()) {
1229 // Assume that object returned from '[self init]' or '[super init]' is not
1230 // 'nil' if we are processing an inlined function/method.
1232 // A defensive callee will (and should) check if the object returned by
1233 // '[super init]' is 'nil' before doing it's own initialization. However,
1234 // since 'nil' is rarely returned in practice, we should not warn when the
1235 // caller to the defensive constructor uses the object in contexts where
1236 // 'nil' is not accepted.
1237 if (!C.inTopFrame() && M.getDecl() &&
1238 M.getDecl()->getMethodFamily() == OMF_init &&
1239 M.isReceiverSelfOrSuper()) {
1240 State = assumeExprIsNonNull(M.getOriginExpr(), State, C);
1243 FoundationClass Cl = findKnownClass(Interface);
1245 // Objects returned from
1246 // [NSArray|NSOrderedSet]::[ObjectAtIndex|ObjectAtIndexedSubscript]
1248 if (Cl == FC_NSArray || Cl == FC_NSOrderedSet) {
1249 Selector Sel = M.getSelector();
1250 if (Sel == ObjectAtIndex || Sel == ObjectAtIndexedSubscript) {
1251 // Go ahead and assume the value is non-nil.
1252 State = assumeExprIsNonNull(M.getOriginExpr(), State, C);
1256 // Objects returned from [NSNull null] are not nil.
1257 if (Cl == FC_NSNull) {
1258 if (M.getSelector() == NullSelector) {
1259 // Go ahead and assume the value is non-nil.
1260 State = assumeExprIsNonNull(M.getOriginExpr(), State, C);
1264 C.addTransition(State);
1267 //===----------------------------------------------------------------------===//
1268 // Check registration.
1269 //===----------------------------------------------------------------------===//
1271 void ento::registerNilArgChecker(CheckerManager &mgr) {
1272 mgr.registerChecker<NilArgChecker>();
1275 void ento::registerCFNumberCreateChecker(CheckerManager &mgr) {
1276 mgr.registerChecker<CFNumberCreateChecker>();
1279 void ento::registerCFRetainReleaseChecker(CheckerManager &mgr) {
1280 mgr.registerChecker<CFRetainReleaseChecker>();
1283 void ento::registerClassReleaseChecker(CheckerManager &mgr) {
1284 mgr.registerChecker<ClassReleaseChecker>();
1287 void ento::registerVariadicMethodTypeChecker(CheckerManager &mgr) {
1288 mgr.registerChecker<VariadicMethodTypeChecker>();
1291 void ento::registerObjCLoopChecker(CheckerManager &mgr) {
1292 mgr.registerChecker<ObjCLoopChecker>();
1296 ento::registerObjCNonNilReturnValueChecker(CheckerManager &mgr) {
1297 mgr.registerChecker<ObjCNonNilReturnValueChecker>();