Coverage Report

Created: 2020-10-24 06:27

/Users/buildslave/jenkins/workspace/coverage/llvm-project/clang/lib/StaticAnalyzer/Checkers/CheckObjCDealloc.cpp
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//==- CheckObjCDealloc.cpp - Check ObjC -dealloc implementation --*- C++ -*-==//
2
//
3
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4
// See https://llvm.org/LICENSE.txt for license information.
5
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
8
//
9
//  This checker analyzes Objective-C -dealloc methods and their callees
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//  to warn about improper releasing of instance variables that back synthesized
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// properties. It warns about missing releases in the following cases:
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//  - When a class has a synthesized instance variable for a 'retain' or 'copy'
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//    property and lacks a -dealloc method in its implementation.
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//  - When a class has a synthesized instance variable for a 'retain'/'copy'
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//   property but the ivar is not released in -dealloc by either -release
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//   or by nilling out the property.
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//
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//  It warns about extra releases in -dealloc (but not in callees) when a
19
//  synthesized instance variable is released in the following cases:
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//  - When the property is 'assign' and is not 'readonly'.
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//  - When the property is 'weak'.
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//
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//  This checker only warns for instance variables synthesized to back
24
//  properties. Handling the more general case would require inferring whether
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//  an instance variable is stored retained or not. For synthesized properties,
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//  this is specified in the property declaration itself.
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//
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//===----------------------------------------------------------------------===//
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#include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h"
31
#include "clang/Analysis/PathDiagnostic.h"
32
#include "clang/AST/Attr.h"
33
#include "clang/AST/DeclObjC.h"
34
#include "clang/AST/Expr.h"
35
#include "clang/AST/ExprObjC.h"
36
#include "clang/Basic/LangOptions.h"
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#include "clang/Basic/TargetInfo.h"
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#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
39
#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
40
#include "clang/StaticAnalyzer/Core/Checker.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/AnalysisManager.h"
42
#include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h"
43
#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
44
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
45
#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
46
#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
47
#include "llvm/Support/raw_ostream.h"
48
49
using namespace clang;
50
using namespace ento;
51
52
/// Indicates whether an instance variable is required to be released in
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/// -dealloc.
54
enum class ReleaseRequirement {
55
  /// The instance variable must be released, either by calling
56
  /// -release on it directly or by nilling it out with a property setter.
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  MustRelease,
58
59
  /// The instance variable must not be directly released with -release.
60
  MustNotReleaseDirectly,
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  /// The requirement for the instance variable could not be determined.
63
  Unknown
64
};
65
66
/// Returns true if the property implementation is synthesized and the
67
/// type of the property is retainable.
68
static bool isSynthesizedRetainableProperty(const ObjCPropertyImplDecl *I,
69
                                            const ObjCIvarDecl **ID,
70
274
                                            const ObjCPropertyDecl **PD) {
71
72
274
  if (I->getPropertyImplementation() != ObjCPropertyImplDecl::Synthesize)
73
0
    return false;
74
75
274
  (*ID) = I->getPropertyIvarDecl();
76
274
  if (!(*ID))
77
0
    return false;
78
79
274
  QualType T = (*ID)->getType();
80
274
  if (!T->isObjCRetainableType())
81
19
    return false;
82
83
255
  (*PD) = I->getPropertyDecl();
84
  // Shouldn't be able to synthesize a property that doesn't exist.
85
255
  assert(*PD);
86
87
255
  return true;
88
255
}
89
90
namespace {
91
92
class ObjCDeallocChecker
93
    : public Checker<check::ASTDecl<ObjCImplementationDecl>,
94
                     check::PreObjCMessage, check::PostObjCMessage,
95
                     check::PreCall,
96
                     check::BeginFunction, check::EndFunction,
97
                     eval::Assume,
98
                     check::PointerEscape,
99
                     check::PreStmt<ReturnStmt>> {
100
101
  mutable IdentifierInfo *NSObjectII, *SenTestCaseII, *XCTestCaseII,
102
      *Block_releaseII, *CIFilterII;
103
104
  mutable Selector DeallocSel, ReleaseSel;
105
106
  std::unique_ptr<BugType> MissingReleaseBugType;
107
  std::unique_ptr<BugType> ExtraReleaseBugType;
108
  std::unique_ptr<BugType> MistakenDeallocBugType;
109
110
public:
111
  ObjCDeallocChecker();
112
113
  void checkASTDecl(const ObjCImplementationDecl *D, AnalysisManager& Mgr,
114
                    BugReporter &BR) const;
115
  void checkBeginFunction(CheckerContext &Ctx) const;
116
  void checkPreObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
117
  void checkPreCall(const CallEvent &Call, CheckerContext &C) const;
118
  void checkPostObjCMessage(const ObjCMethodCall &M, CheckerContext &C) const;
119
120
  ProgramStateRef evalAssume(ProgramStateRef State, SVal Cond,
121
                             bool Assumption) const;
122
123
  ProgramStateRef checkPointerEscape(ProgramStateRef State,
124
                                     const InvalidatedSymbols &Escaped,
125
                                     const CallEvent *Call,
126
                                     PointerEscapeKind Kind) const;
127
  void checkPreStmt(const ReturnStmt *RS, CheckerContext &C) const;
128
  void checkEndFunction(const ReturnStmt *RS, CheckerContext &Ctx) const;
129
130
private:
131
  void diagnoseMissingReleases(CheckerContext &C) const;
132
133
  bool diagnoseExtraRelease(SymbolRef ReleasedValue, const ObjCMethodCall &M,
134
                            CheckerContext &C) const;
135
136
  bool diagnoseMistakenDealloc(SymbolRef DeallocedValue,
137
                               const ObjCMethodCall &M,
138
                               CheckerContext &C) const;
139
140
  SymbolRef getValueReleasedByNillingOut(const ObjCMethodCall &M,
141
                                         CheckerContext &C) const;
142
143
  const ObjCIvarRegion *getIvarRegionForIvarSymbol(SymbolRef IvarSym) const;
144
  SymbolRef getInstanceSymbolFromIvarSymbol(SymbolRef IvarSym) const;
145
146
  const ObjCPropertyImplDecl*
147
  findPropertyOnDeallocatingInstance(SymbolRef IvarSym,
148
                                     CheckerContext &C) const;
149
150
  ReleaseRequirement
151
  getDeallocReleaseRequirement(const ObjCPropertyImplDecl *PropImpl) const;
152
153
  bool isInInstanceDealloc(const CheckerContext &C, SVal &SelfValOut) const;
154
  bool isInInstanceDealloc(const CheckerContext &C, const LocationContext *LCtx,
155
                           SVal &SelfValOut) const;
156
  bool instanceDeallocIsOnStack(const CheckerContext &C,
157
                                SVal &InstanceValOut) const;
158
159
  bool isSuperDeallocMessage(const ObjCMethodCall &M) const;
160
161
  const ObjCImplDecl *getContainingObjCImpl(const LocationContext *LCtx) const;
162
163
  const ObjCPropertyDecl *
164
  findShadowedPropertyDecl(const ObjCPropertyImplDecl *PropImpl) const;
165
166
  void transitionToReleaseValue(CheckerContext &C, SymbolRef Value) const;
167
  ProgramStateRef removeValueRequiringRelease(ProgramStateRef State,
168
                                              SymbolRef InstanceSym,
169
                                              SymbolRef ValueSym) const;
170
171
  void initIdentifierInfoAndSelectors(ASTContext &Ctx) const;
172
173
  bool classHasSeparateTeardown(const ObjCInterfaceDecl *ID) const;
174
175
  bool isReleasedByCIFilterDealloc(const ObjCPropertyImplDecl *PropImpl) const;
176
  bool isNibLoadedIvarWithoutRetain(const ObjCPropertyImplDecl *PropImpl) const;
177
};
178
} // End anonymous namespace.
179
180
181
/// Maps from the symbol for a class instance to the set of
182
/// symbols remaining that must be released in -dealloc.
183
REGISTER_SET_FACTORY_WITH_PROGRAMSTATE(SymbolSet, SymbolRef)
184
REGISTER_MAP_WITH_PROGRAMSTATE(UnreleasedIvarMap, SymbolRef, SymbolSet)
185
186
187
/// An AST check that diagnose when the class requires a -dealloc method and
188
/// is missing one.
189
void ObjCDeallocChecker::checkASTDecl(const ObjCImplementationDecl *D,
190
                                      AnalysisManager &Mgr,
191
128
                                      BugReporter &BR) const {
192
128
  assert(Mgr.getLangOpts().getGC() != LangOptions::GCOnly);
193
128
  assert(!Mgr.getLangOpts().ObjCAutoRefCount);
194
128
  initIdentifierInfoAndSelectors(Mgr.getASTContext());
195
196
128
  const ObjCInterfaceDecl *ID = D->getClassInterface();
197
  // If the class is known to have a lifecycle with a separate teardown method
198
  // then it may not require a -dealloc method.
199
128
  if (classHasSeparateTeardown(ID))
200
24
    return;
201
202
  // Does the class contain any synthesized properties that are retainable?
203
  // If not, skip the check entirely.
204
104
  const ObjCPropertyImplDecl *PropImplRequiringRelease = nullptr;
205
104
  bool HasOthers = false;
206
109
  for (const auto *I : D->property_impls()) {
207
109
    if (getDeallocReleaseRequirement(I) == ReleaseRequirement::MustRelease) {
208
74
      if (!PropImplRequiringRelease)
209
64
        PropImplRequiringRelease = I;
210
10
      else {
211
10
        HasOthers = true;
212
10
        break;
213
10
      }
214
74
    }
215
109
  }
216
217
104
  if (!PropImplRequiringRelease)
218
40
    return;
219
220
64
  const ObjCMethodDecl *MD = nullptr;
221
222
  // Scan the instance methods for "dealloc".
223
81
  for (const auto *I : D->instance_methods()) {
224
81
    if (I->getSelector() == DeallocSel) {
225
59
      MD = I;
226
59
      break;
227
59
    }
228
81
  }
229
230
64
  if (!MD) { // No dealloc found.
231
5
    const char* Name = "Missing -dealloc";
232
233
5
    std::string Buf;
234
5
    llvm::raw_string_ostream OS(Buf);
235
5
    OS << "'" << *D << "' lacks a 'dealloc' instance method but "
236
5
       << "must release '" << *PropImplRequiringRelease->getPropertyIvarDecl()
237
5
       << "'";
238
239
5
    if (HasOthers)
240
1
      OS << " and others";
241
5
    PathDiagnosticLocation DLoc =
242
5
        PathDiagnosticLocation::createBegin(D, BR.getSourceManager());
243
244
5
    BR.EmitBasicReport(D, this, Name, categories::CoreFoundationObjectiveC,
245
5
                       OS.str(), DLoc);
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5
    return;
247
5
  }
248
64
}
249
250
/// If this is the beginning of -dealloc, mark the values initially stored in
251
/// instance variables that must be released by the end of -dealloc
252
/// as unreleased in the state.
253
void ObjCDeallocChecker::checkBeginFunction(
254
606
    CheckerContext &C) const {
255
606
  initIdentifierInfoAndSelectors(C.getASTContext());
256
257
  // Only do this if the current method is -dealloc.
258
606
  SVal SelfVal;
259
606
  if (!isInInstanceDealloc(C, SelfVal))
260
513
    return;
261
262
93
  SymbolRef SelfSymbol = SelfVal.getAsSymbol();
263
264
93
  const LocationContext *LCtx = C.getLocationContext();
265
93
  ProgramStateRef InitialState = C.getState();
266
267
93
  ProgramStateRef State = InitialState;
268
269
93
  SymbolSet::Factory &F = State->getStateManager().get_context<SymbolSet>();
270
271
  // Symbols that must be released by the end of the -dealloc;
272
93
  SymbolSet RequiredReleases = F.getEmptySet();
273
274
  // If we're an inlined -dealloc, we should add our symbols to the existing
275
  // set from our subclass.
276
93
  if (const SymbolSet *CurrSet = State->get<UnreleasedIvarMap>(SelfSymbol))
277
4
    RequiredReleases = *CurrSet;
278
279
133
  for (auto *PropImpl : getContainingObjCImpl(LCtx)->property_impls()) {
280
133
    ReleaseRequirement Requirement = getDeallocReleaseRequirement(PropImpl);
281
133
    if (Requirement != ReleaseRequirement::MustRelease)
282
33
      continue;
283
284
100
    SVal LVal = State->getLValue(PropImpl->getPropertyIvarDecl(), SelfVal);
285
100
    Optional<Loc> LValLoc = LVal.getAs<Loc>();
286
100
    if (!LValLoc)
287
0
      continue;
288
289
100
    SVal InitialVal = State->getSVal(LValLoc.getValue());
290
100
    SymbolRef Symbol = InitialVal.getAsSymbol();
291
100
    if (!Symbol || !isa<SymbolRegionValue>(Symbol))
292
2
      continue;
293
294
    // Mark the value as requiring a release.
295
98
    RequiredReleases = F.add(RequiredReleases, Symbol);
296
98
  }
297
298
93
  if (!RequiredReleases.isEmpty()) {
299
69
    State = State->set<UnreleasedIvarMap>(SelfSymbol, RequiredReleases);
300
69
  }
301
302
93
  if (State != InitialState) {
303
69
    C.addTransition(State);
304
69
  }
305
93
}
306
307
/// Given a symbol for an ivar, return the ivar region it was loaded from.
308
/// Returns nullptr if the instance symbol cannot be found.
309
const ObjCIvarRegion *
310
926
ObjCDeallocChecker::getIvarRegionForIvarSymbol(SymbolRef IvarSym) const {
311
926
  return dyn_cast_or_null<ObjCIvarRegion>(IvarSym->getOriginRegion());
312
926
}
313
314
/// Given a symbol for an ivar, return a symbol for the instance containing
315
/// the ivar. Returns nullptr if the instance symbol cannot be found.
316
SymbolRef
317
335
ObjCDeallocChecker::getInstanceSymbolFromIvarSymbol(SymbolRef IvarSym) const {
318
319
335
  const ObjCIvarRegion *IvarRegion = getIvarRegionForIvarSymbol(IvarSym);
320
335
  if (!IvarRegion)
321
184
    return nullptr;
322
323
151
  return IvarRegion->getSymbolicBase()->getSymbol();
324
151
}
325
326
/// If we are in -dealloc or -dealloc is on the stack, handle the call if it is
327
/// a release or a nilling-out property setter.
328
void ObjCDeallocChecker::checkPreObjCMessage(
329
592
    const ObjCMethodCall &M, CheckerContext &C) const {
330
  // Only run if -dealloc is on the stack.
331
592
  SVal DeallocedInstance;
332
592
  if (!instanceDeallocIsOnStack(C, DeallocedInstance))
333
352
    return;
334
335
240
  SymbolRef ReleasedValue = nullptr;
336
337
240
  if (M.getSelector() == ReleaseSel) {
338
61
    ReleasedValue = M.getReceiverSVal().getAsSymbol();
339
179
  } else if (M.getSelector() == DeallocSel && 
!M.isReceiverSelfOrSuper()102
) {
340
5
    if (diagnoseMistakenDealloc(M.getReceiverSVal().getAsSymbol(), M, C))
341
2
      return;
342
238
  }
343
344
238
  if (ReleasedValue) {
345
    // An instance variable symbol was released with -release:
346
    //    [_property release];
347
61
    if (diagnoseExtraRelease(ReleasedValue,M, C))
348
5
      return;
349
177
  } else {
350
    // An instance variable symbol was released nilling out its property:
351
    //    self.property = nil;
352
177
    ReleasedValue = getValueReleasedByNillingOut(M, C);
353
177
  }
354
355
233
  if (!ReleasedValue)
356
162
    return;
357
358
71
  transitionToReleaseValue(C, ReleasedValue);
359
71
}
360
361
/// If we are in -dealloc or -dealloc is on the stack, handle the call if it is
362
/// call to Block_release().
363
void ObjCDeallocChecker::checkPreCall(const CallEvent &Call,
364
1.02k
                                      CheckerContext &C) const {
365
1.02k
  const IdentifierInfo *II = Call.getCalleeIdentifier();
366
1.02k
  if (II != Block_releaseII)
367
1.02k
    return;
368
369
2
  if (Call.getNumArgs() != 1)
370
0
    return;
371
372
2
  SymbolRef ReleasedValue = Call.getArgSVal(0).getAsSymbol();
373
2
  if (!ReleasedValue)
374
0
    return;
375
376
2
  transitionToReleaseValue(C, ReleasedValue);
377
2
}
378
/// If the message was a call to '[super dealloc]', diagnose any missing
379
/// releases.
380
void ObjCDeallocChecker::checkPostObjCMessage(
381
586
    const ObjCMethodCall &M, CheckerContext &C) const {
382
  // We perform this check post-message so that if the super -dealloc
383
  // calls a helper method and that this class overrides, any ivars released in
384
  // the helper method will be recorded before checking.
385
586
  if (isSuperDeallocMessage(M))
386
97
    diagnoseMissingReleases(C);
387
586
}
388
389
/// Check for missing releases even when -dealloc does not call
390
/// '[super dealloc]'.
391
void ObjCDeallocChecker::checkEndFunction(
392
618
    const ReturnStmt *RS, CheckerContext &C) const {
393
618
  diagnoseMissingReleases(C);
394
618
}
395
396
/// Check for missing releases on early return.
397
void ObjCDeallocChecker::checkPreStmt(
398
223
    const ReturnStmt *RS, CheckerContext &C) const {
399
223
  diagnoseMissingReleases(C);
400
223
}
401
402
/// When a symbol is assumed to be nil, remove it from the set of symbols
403
/// require to be nil.
404
ProgramStateRef ObjCDeallocChecker::evalAssume(ProgramStateRef State, SVal Cond,
405
3.12k
                                               bool Assumption) const {
406
3.12k
  if (State->get<UnreleasedIvarMap>().isEmpty())
407
2.82k
    return State;
408
409
300
  auto *CondBSE = dyn_cast_or_null<BinarySymExpr>(Cond.getAsSymbol());
410
300
  if (!CondBSE)
411
25
    return State;
412
413
275
  BinaryOperator::Opcode OpCode = CondBSE->getOpcode();
414
275
  if (Assumption) {
415
198
    if (OpCode != BO_EQ)
416
197
      return State;
417
77
  } else {
418
77
    if (OpCode != BO_NE)
419
1
      return State;
420
77
  }
421
422
77
  SymbolRef NullSymbol = nullptr;
423
77
  if (auto *SIE = dyn_cast<SymIntExpr>(CondBSE)) {
424
77
    const llvm::APInt &RHS = SIE->getRHS();
425
77
    if (RHS != 0)
426
0
      return State;
427
77
    NullSymbol = SIE->getLHS();
428
0
  } else if (auto *SIE = dyn_cast<IntSymExpr>(CondBSE)) {
429
0
    const llvm::APInt &LHS = SIE->getLHS();
430
0
    if (LHS != 0)
431
0
      return State;
432
0
    NullSymbol = SIE->getRHS();
433
0
  } else {
434
0
    return State;
435
0
  }
436
437
77
  SymbolRef InstanceSymbol = getInstanceSymbolFromIvarSymbol(NullSymbol);
438
77
  if (!InstanceSymbol)
439
22
    return State;
440
441
55
  State = removeValueRequiringRelease(State, InstanceSymbol, NullSymbol);
442
443
55
  return State;
444
55
}
445
446
/// If a symbol escapes conservatively assume unseen code released it.
447
ProgramStateRef ObjCDeallocChecker::checkPointerEscape(
448
    ProgramStateRef State, const InvalidatedSymbols &Escaped,
449
905
    const CallEvent *Call, PointerEscapeKind Kind) const {
450
451
905
  if (State->get<UnreleasedIvarMap>().isEmpty())
452
694
    return State;
453
454
  // Don't treat calls to '[super dealloc]' as escaping for the purposes
455
  // of this checker. Because the checker diagnoses missing releases in the
456
  // post-message handler for '[super dealloc], escaping here would cause
457
  // the checker to never warn.
458
211
  auto *OMC = dyn_cast_or_null<ObjCMethodCall>(Call);
459
211
  if (OMC && 
isSuperDeallocMessage(*OMC)202
)
460
67
    return State;
461
462
185
  
for (const auto &Sym : Escaped)144
{
463
185
    if (!Call || 
(183
Call183
&&
!Call->isInSystemHeader()183
)) {
464
      // If Sym is a symbol for an object with instance variables that
465
      // must be released, remove these obligations when the object escapes
466
      // unless via a call to a system function. System functions are
467
      // very unlikely to release instance variables on objects passed to them,
468
      // and are frequently called on 'self' in -dealloc (e.g., to remove
469
      // observers) -- we want to avoid false negatives from escaping on
470
      // them.
471
55
      State = State->remove<UnreleasedIvarMap>(Sym);
472
55
    }
473
474
475
185
    SymbolRef InstanceSymbol = getInstanceSymbolFromIvarSymbol(Sym);
476
185
    if (!InstanceSymbol)
477
146
      continue;
478
479
39
    State = removeValueRequiringRelease(State, InstanceSymbol, Sym);
480
39
  }
481
482
144
  return State;
483
144
}
484
485
/// Report any unreleased instance variables for the current instance being
486
/// dealloced.
487
938
void ObjCDeallocChecker::diagnoseMissingReleases(CheckerContext &C) const {
488
938
  ProgramStateRef State = C.getState();
489
490
938
  SVal SelfVal;
491
938
  if (!isInInstanceDealloc(C, SelfVal))
492
748
    return;
493
494
190
  const MemRegion *SelfRegion = SelfVal.castAs<loc::MemRegionVal>().getRegion();
495
190
  const LocationContext *LCtx = C.getLocationContext();
496
497
190
  ExplodedNode *ErrNode = nullptr;
498
499
190
  SymbolRef SelfSym = SelfVal.getAsSymbol();
500
190
  if (!SelfSym)
501
0
    return;
502
503
190
  const SymbolSet *OldUnreleased = State->get<UnreleasedIvarMap>(SelfSym);
504
190
  if (!OldUnreleased)
505
130
    return;
506
507
60
  SymbolSet NewUnreleased = *OldUnreleased;
508
60
  SymbolSet::Factory &F = State->getStateManager().get_context<SymbolSet>();
509
510
60
  ProgramStateRef InitialState = State;
511
512
64
  for (auto *IvarSymbol : *OldUnreleased) {
513
64
    const TypedValueRegion *TVR =
514
64
        cast<SymbolRegionValue>(IvarSymbol)->getRegion();
515
64
    const ObjCIvarRegion *IvarRegion = cast<ObjCIvarRegion>(TVR);
516
517
    // Don't warn if the ivar is not for this instance.
518
64
    if (SelfRegion != IvarRegion->getSuperRegion())
519
0
      continue;
520
521
64
    const ObjCIvarDecl *IvarDecl = IvarRegion->getDecl();
522
    // Prevent an inlined call to -dealloc in a super class from warning
523
    // about the values the subclass's -dealloc should release.
524
64
    if (IvarDecl->getContainingInterface() !=
525
64
        cast<ObjCMethodDecl>(LCtx->getDecl())->getClassInterface())
526
4
      continue;
527
528
    // Prevents diagnosing multiple times for the same instance variable
529
    // at, for example, both a return and at the end of the function.
530
60
    NewUnreleased = F.remove(NewUnreleased, IvarSymbol);
531
532
60
    if (State->getStateManager()
533
60
            .getConstraintManager()
534
60
            .isNull(State, IvarSymbol)
535
0
            .isConstrainedTrue()) {
536
0
      continue;
537
0
    }
538
539
    // A missing release manifests as a leak, so treat as a non-fatal error.
540
60
    if (!ErrNode)
541
58
      ErrNode = C.generateNonFatalErrorNode();
542
    // If we've already reached this node on another path, return without
543
    // diagnosing.
544
60
    if (!ErrNode)
545
0
      return;
546
547
60
    std::string Buf;
548
60
    llvm::raw_string_ostream OS(Buf);
549
550
60
    const ObjCInterfaceDecl *Interface = IvarDecl->getContainingInterface();
551
    // If the class is known to have a lifecycle with teardown that is
552
    // separate from -dealloc, do not warn about missing releases. We
553
    // suppress here (rather than not tracking for instance variables in
554
    // such classes) because these classes are rare.
555
60
    if (classHasSeparateTeardown(Interface))
556
10
      return;
557
558
50
    ObjCImplDecl *ImplDecl = Interface->getImplementation();
559
560
50
    const ObjCPropertyImplDecl *PropImpl =
561
50
        ImplDecl->FindPropertyImplIvarDecl(IvarDecl->getIdentifier());
562
563
50
    const ObjCPropertyDecl *PropDecl = PropImpl->getPropertyDecl();
564
565
50
    assert(PropDecl->getSetterKind() == ObjCPropertyDecl::Copy ||
566
50
           PropDecl->getSetterKind() == ObjCPropertyDecl::Retain);
567
568
50
    OS << "The '" << *IvarDecl << "' ivar in '" << *ImplDecl
569
50
       << "' was ";
570
571
50
    if (PropDecl->getSetterKind() == ObjCPropertyDecl::Retain)
572
46
      OS << "retained";
573
4
    else
574
4
      OS << "copied";
575
576
50
    OS << " by a synthesized property but not released"
577
50
          " before '[super dealloc]'";
578
579
50
    auto BR = std::make_unique<PathSensitiveBugReport>(*MissingReleaseBugType,
580
50
                                                       OS.str(), ErrNode);
581
50
    C.emitReport(std::move(BR));
582
50
  }
583
584
50
  if (NewUnreleased.isEmpty()) {
585
46
    State = State->remove<UnreleasedIvarMap>(SelfSym);
586
4
  } else {
587
4
    State = State->set<UnreleasedIvarMap>(SelfSym, NewUnreleased);
588
4
  }
589
590
50
  if (ErrNode) {
591
48
    C.addTransition(State, ErrNode);
592
2
  } else if (State != InitialState) {
593
0
    C.addTransition(State);
594
0
  }
595
596
  // Make sure that after checking in the top-most frame the list of
597
  // tracked ivars is empty. This is intended to detect accidental leaks in
598
  // the UnreleasedIvarMap program state.
599
50
  assert(!LCtx->inTopFrame() || State->get<UnreleasedIvarMap>().isEmpty());
600
50
}
601
602
/// Given a symbol, determine whether the symbol refers to an ivar on
603
/// the top-most deallocating instance. If so, find the property for that
604
/// ivar, if one exists. Otherwise return null.
605
const ObjCPropertyImplDecl *
606
ObjCDeallocChecker::findPropertyOnDeallocatingInstance(
607
65
    SymbolRef IvarSym, CheckerContext &C) const {
608
65
  SVal DeallocedInstance;
609
65
  if (!isInInstanceDealloc(C, DeallocedInstance))
610
13
    return nullptr;
611
612
  // Try to get the region from which the ivar value was loaded.
613
52
  auto *IvarRegion = getIvarRegionForIvarSymbol(IvarSym);
614
52
  if (!IvarRegion)
615
16
    return nullptr;
616
617
  // Don't try to find the property if the ivar was not loaded from the
618
  // given instance.
619
36
  if (DeallocedInstance.castAs<loc::MemRegionVal>().getRegion() !=
620
36
      IvarRegion->getSuperRegion())
621
1
    return nullptr;
622
623
35
  const LocationContext *LCtx = C.getLocationContext();
624
35
  const ObjCIvarDecl *IvarDecl = IvarRegion->getDecl();
625
626
35
  const ObjCImplDecl *Container = getContainingObjCImpl(LCtx);
627
35
  const ObjCPropertyImplDecl *PropImpl =
628
35
      Container->FindPropertyImplIvarDecl(IvarDecl->getIdentifier());
629
35
  return PropImpl;
630
35
}
631
632
/// Emits a warning if the current context is -dealloc and ReleasedValue
633
/// must not be directly released in a -dealloc. Returns true if a diagnostic
634
/// was emitted.
635
bool ObjCDeallocChecker::diagnoseExtraRelease(SymbolRef ReleasedValue,
636
                                              const ObjCMethodCall &M,
637
61
                                              CheckerContext &C) const {
638
  // Try to get the region from which the released value was loaded.
639
  // Note that, unlike diagnosing for missing releases, here we don't track
640
  // values that must not be released in the state. This is because even if
641
  // these values escape, it is still an error under the rules of MRR to
642
  // release them in -dealloc.
643
61
  const ObjCPropertyImplDecl *PropImpl =
644
61
      findPropertyOnDeallocatingInstance(ReleasedValue, C);
645
646
61
  if (!PropImpl)
647
31
    return false;
648
649
  // If the ivar belongs to a property that must not be released directly
650
  // in dealloc, emit a warning.
651
30
  if (getDeallocReleaseRequirement(PropImpl) !=
652
24
      ReleaseRequirement::MustNotReleaseDirectly) {
653
24
    return false;
654
24
  }
655
656
  // If the property is readwrite but it shadows a read-only property in its
657
  // external interface, treat the property a read-only. If the outside
658
  // world cannot write to a property then the internal implementation is free
659
  // to make its own convention about whether the value is stored retained
660
  // or not. We look up the shadow here rather than in
661
  // getDeallocReleaseRequirement() because doing so can be expensive.
662
6
  const ObjCPropertyDecl *PropDecl = findShadowedPropertyDecl(PropImpl);
663
6
  if (PropDecl) {
664
1
    if (PropDecl->isReadOnly())
665
1
      return false;
666
5
  } else {
667
5
    PropDecl = PropImpl->getPropertyDecl();
668
5
  }
669
670
5
  ExplodedNode *ErrNode = C.generateNonFatalErrorNode();
671
5
  if (!ErrNode)
672
0
    return false;
673
674
5
  std::string Buf;
675
5
  llvm::raw_string_ostream OS(Buf);
676
677
5
  assert(PropDecl->getSetterKind() == ObjCPropertyDecl::Weak ||
678
5
         (PropDecl->getSetterKind() == ObjCPropertyDecl::Assign &&
679
5
          !PropDecl->isReadOnly()) ||
680
5
         isReleasedByCIFilterDealloc(PropImpl)
681
5
         );
682
683
5
  const ObjCImplDecl *Container = getContainingObjCImpl(C.getLocationContext());
684
5
  OS << "The '" << *PropImpl->getPropertyIvarDecl()
685
5
     << "' ivar in '" << *Container;
686
687
688
5
  if (isReleasedByCIFilterDealloc(PropImpl)) {
689
2
    OS << "' will be released by '-[CIFilter dealloc]' but also released here";
690
3
  } else {
691
3
    OS << "' was synthesized for ";
692
693
3
    if (PropDecl->getSetterKind() == ObjCPropertyDecl::Weak)
694
2
      OS << "a weak";
695
1
    else
696
1
      OS << "an assign, readwrite";
697
698
3
    OS <<  " property but was released in 'dealloc'";
699
3
  }
700
701
5
  auto BR = std::make_unique<PathSensitiveBugReport>(*ExtraReleaseBugType,
702
5
                                                     OS.str(), ErrNode);
703
5
  BR->addRange(M.getOriginExpr()->getSourceRange());
704
705
5
  C.emitReport(std::move(BR));
706
707
5
  return true;
708
5
}
709
710
/// Emits a warning if the current context is -dealloc and DeallocedValue
711
/// must not be directly dealloced in a -dealloc. Returns true if a diagnostic
712
/// was emitted.
713
bool ObjCDeallocChecker::diagnoseMistakenDealloc(SymbolRef DeallocedValue,
714
                                                 const ObjCMethodCall &M,
715
5
                                                 CheckerContext &C) const {
716
  // TODO: Apart from unknown/undefined receivers, this may happen when
717
  // dealloc is called as a class method. Should we warn?
718
5
  if (!DeallocedValue)
719
1
    return false;
720
721
  // Find the property backing the instance variable that M
722
  // is dealloc'ing.
723
4
  const ObjCPropertyImplDecl *PropImpl =
724
4
      findPropertyOnDeallocatingInstance(DeallocedValue, C);
725
4
  if (!PropImpl)
726
2
    return false;
727
728
2
  if (getDeallocReleaseRequirement(PropImpl) !=
729
0
      ReleaseRequirement::MustRelease) {
730
0
    return false;
731
0
  }
732
733
2
  ExplodedNode *ErrNode = C.generateErrorNode();
734
2
  if (!ErrNode)
735
0
    return false;
736
737
2
  std::string Buf;
738
2
  llvm::raw_string_ostream OS(Buf);
739
740
2
  OS << "'" << *PropImpl->getPropertyIvarDecl()
741
2
     << "' should be released rather than deallocated";
742
743
2
  auto BR = std::make_unique<PathSensitiveBugReport>(*MistakenDeallocBugType,
744
2
                                                     OS.str(), ErrNode);
745
2
  BR->addRange(M.getOriginExpr()->getSourceRange());
746
747
2
  C.emitReport(std::move(BR));
748
749
2
  return true;
750
2
}
751
752
ObjCDeallocChecker::ObjCDeallocChecker()
753
    : NSObjectII(nullptr), SenTestCaseII(nullptr), XCTestCaseII(nullptr),
754
41
      CIFilterII(nullptr) {
755
756
41
  MissingReleaseBugType.reset(
757
41
      new BugType(this, "Missing ivar release (leak)",
758
41
                  categories::MemoryRefCount));
759
760
41
  ExtraReleaseBugType.reset(
761
41
      new BugType(this, "Extra ivar release",
762
41
                  categories::MemoryRefCount));
763
764
41
  MistakenDeallocBugType.reset(
765
41
      new BugType(this, "Mistaken dealloc",
766
41
                  categories::MemoryRefCount));
767
41
}
768
769
void ObjCDeallocChecker::initIdentifierInfoAndSelectors(
770
734
    ASTContext &Ctx) const {
771
734
  if (NSObjectII)
772
693
    return;
773
774
41
  NSObjectII = &Ctx.Idents.get("NSObject");
775
41
  SenTestCaseII = &Ctx.Idents.get("SenTestCase");
776
41
  XCTestCaseII = &Ctx.Idents.get("XCTestCase");
777
41
  Block_releaseII = &Ctx.Idents.get("_Block_release");
778
41
  CIFilterII = &Ctx.Idents.get("CIFilter");
779
780
41
  IdentifierInfo *DeallocII = &Ctx.Idents.get("dealloc");
781
41
  IdentifierInfo *ReleaseII = &Ctx.Idents.get("release");
782
41
  DeallocSel = Ctx.Selectors.getSelector(0, &DeallocII);
783
41
  ReleaseSel = Ctx.Selectors.getSelector(0, &ReleaseII);
784
41
}
785
786
/// Returns true if M is a call to '[super dealloc]'.
787
bool ObjCDeallocChecker::isSuperDeallocMessage(
788
788
    const ObjCMethodCall &M) const {
789
788
  if (M.getOriginExpr()->getReceiverKind() != ObjCMessageExpr::SuperInstance)
790
611
    return false;
791
792
177
  return M.getSelector() == DeallocSel;
793
177
}
794
795
/// Returns the ObjCImplDecl containing the method declaration in LCtx.
796
const ObjCImplDecl *
797
133
ObjCDeallocChecker::getContainingObjCImpl(const LocationContext *LCtx) const {
798
133
  auto *MD = cast<ObjCMethodDecl>(LCtx->getDecl());
799
133
  return cast<ObjCImplDecl>(MD->getDeclContext());
800
133
}
801
802
/// Returns the property that shadowed by PropImpl if one exists and
803
/// nullptr otherwise.
804
const ObjCPropertyDecl *ObjCDeallocChecker::findShadowedPropertyDecl(
805
6
    const ObjCPropertyImplDecl *PropImpl) const {
806
6
  const ObjCPropertyDecl *PropDecl = PropImpl->getPropertyDecl();
807
808
  // Only readwrite properties can shadow.
809
6
  if (PropDecl->isReadOnly())
810
1
    return nullptr;
811
812
5
  auto *CatDecl = dyn_cast<ObjCCategoryDecl>(PropDecl->getDeclContext());
813
814
  // Only class extensions can contain shadowing properties.
815
5
  if (!CatDecl || 
!CatDecl->IsClassExtension()1
)
816
4
    return nullptr;
817
818
1
  IdentifierInfo *ID = PropDecl->getIdentifier();
819
1
  DeclContext::lookup_result R = CatDecl->getClassInterface()->lookup(ID);
820
1
  for (DeclContext::lookup_iterator I = R.begin(), E = R.end(); I != E; 
++I0
) {
821
1
    auto *ShadowedPropDecl = dyn_cast<ObjCPropertyDecl>(*I);
822
1
    if (!ShadowedPropDecl)
823
0
      continue;
824
825
1
    if (ShadowedPropDecl->isInstanceProperty()) {
826
1
      assert(ShadowedPropDecl->isReadOnly());
827
1
      return ShadowedPropDecl;
828
1
    }
829
1
  }
830
831
0
  return nullptr;
832
1
}
833
834
/// Add a transition noting the release of the given value.
835
void ObjCDeallocChecker::transitionToReleaseValue(CheckerContext &C,
836
73
                                                  SymbolRef Value) const {
837
73
  assert(Value);
838
73
  SymbolRef InstanceSym = getInstanceSymbolFromIvarSymbol(Value);
839
73
  if (!InstanceSym)
840
16
    return;
841
57
  ProgramStateRef InitialState = C.getState();
842
843
57
  ProgramStateRef ReleasedState =
844
57
      removeValueRequiringRelease(InitialState, InstanceSym, Value);
845
846
57
  if (ReleasedState != InitialState) {
847
48
    C.addTransition(ReleasedState);
848
48
  }
849
57
}
850
851
/// Remove the Value requiring a release from the tracked set for
852
/// Instance and return the resultant state.
853
ProgramStateRef ObjCDeallocChecker::removeValueRequiringRelease(
854
151
    ProgramStateRef State, SymbolRef Instance, SymbolRef Value) const {
855
151
  assert(Instance);
856
151
  assert(Value);
857
151
  const ObjCIvarRegion *RemovedRegion = getIvarRegionForIvarSymbol(Value);
858
151
  if (!RemovedRegion)
859
0
    return State;
860
861
151
  const SymbolSet *Unreleased = State->get<UnreleasedIvarMap>(Instance);
862
151
  if (!Unreleased)
863
11
    return State;
864
865
  // Mark the value as no longer requiring a release.
866
140
  SymbolSet::Factory &F = State->getStateManager().get_context<SymbolSet>();
867
140
  SymbolSet NewUnreleased = *Unreleased;
868
388
  for (auto &Sym : *Unreleased) {
869
388
    const ObjCIvarRegion *UnreleasedRegion = getIvarRegionForIvarSymbol(Sym);
870
388
    assert(UnreleasedRegion);
871
388
    if (RemovedRegion->getDecl() == UnreleasedRegion->getDecl()) {
872
90
      NewUnreleased = F.remove(NewUnreleased, Sym);
873
90
    }
874
388
  }
875
876
140
  if (NewUnreleased.isEmpty()) {
877
24
    return State->remove<UnreleasedIvarMap>(Instance);
878
24
  }
879
880
116
  return State->set<UnreleasedIvarMap>(Instance, NewUnreleased);
881
116
}
882
883
/// Determines whether the instance variable for \p PropImpl must or must not be
884
/// released in -dealloc or whether it cannot be determined.
885
ReleaseRequirement ObjCDeallocChecker::getDeallocReleaseRequirement(
886
274
    const ObjCPropertyImplDecl *PropImpl) const {
887
274
  const ObjCIvarDecl *IvarDecl;
888
274
  const ObjCPropertyDecl *PropDecl;
889
274
  if (!isSynthesizedRetainableProperty(PropImpl, &IvarDecl, &PropDecl))
890
19
    return ReleaseRequirement::Unknown;
891
892
255
  ObjCPropertyDecl::SetterKind SK = PropDecl->getSetterKind();
893
894
255
  switch (SK) {
895
  // Retain and copy setters retain/copy their values before storing and so
896
  // the value in their instance variables must be released in -dealloc.
897
229
  case ObjCPropertyDecl::Retain:
898
229
  case ObjCPropertyDecl::Copy:
899
229
    if (isReleasedByCIFilterDealloc(PropImpl))
900
28
      return ReleaseRequirement::MustNotReleaseDirectly;
901
902
201
    if (isNibLoadedIvarWithoutRetain(PropImpl))
903
2
      return ReleaseRequirement::Unknown;
904
905
199
    return ReleaseRequirement::MustRelease;
906
907
10
  case ObjCPropertyDecl::Weak:
908
10
    return ReleaseRequirement::MustNotReleaseDirectly;
909
910
16
  case ObjCPropertyDecl::Assign:
911
    // It is common for the ivars for read-only assign properties to
912
    // always be stored retained, so their release requirement cannot be
913
    // be determined.
914
16
    if (PropDecl->isReadOnly())
915
3
      return ReleaseRequirement::Unknown;
916
917
13
    return ReleaseRequirement::MustNotReleaseDirectly;
918
0
  }
919
0
  llvm_unreachable("Unrecognized setter kind");
920
0
}
921
922
/// Returns the released value if M is a call a setter that releases
923
/// and nils out its underlying instance variable.
924
SymbolRef
925
ObjCDeallocChecker::getValueReleasedByNillingOut(const ObjCMethodCall &M,
926
177
                                                 CheckerContext &C) const {
927
177
  SVal ReceiverVal = M.getReceiverSVal();
928
177
  if (!ReceiverVal.isValid())
929
20
    return nullptr;
930
931
157
  if (M.getNumArgs() == 0)
932
117
    return nullptr;
933
934
40
  if (!M.getArgExpr(0)->getType()->isObjCRetainableType())
935
4
    return nullptr;
936
937
  // Is the first argument nil?
938
36
  SVal Arg = M.getArgSVal(0);
939
36
  ProgramStateRef notNilState, nilState;
940
36
  std::tie(notNilState, nilState) =
941
36
      M.getState()->assume(Arg.castAs<DefinedOrUnknownSVal>());
942
36
  if (!(nilState && 
!notNilState19
))
943
18
    return nullptr;
944
945
18
  const ObjCPropertyDecl *Prop = M.getAccessedProperty();
946
18
  if (!Prop)
947
1
    return nullptr;
948
949
17
  ObjCIvarDecl *PropIvarDecl = Prop->getPropertyIvarDecl();
950
17
  if (!PropIvarDecl)
951
2
    return nullptr;
952
953
15
  ProgramStateRef State = C.getState();
954
955
15
  SVal LVal = State->getLValue(PropIvarDecl, ReceiverVal);
956
15
  Optional<Loc> LValLoc = LVal.getAs<Loc>();
957
15
  if (!LValLoc)
958
0
    return nullptr;
959
960
15
  SVal CurrentValInIvar = State->getSVal(LValLoc.getValue());
961
15
  return CurrentValInIvar.getAsSymbol();
962
15
}
963
964
/// Returns true if the current context is a call to -dealloc and false
965
/// otherwise. If true, it also sets SelfValOut to the value of
966
/// 'self'.
967
bool ObjCDeallocChecker::isInInstanceDealloc(const CheckerContext &C,
968
1.60k
                                             SVal &SelfValOut) const {
969
1.60k
  return isInInstanceDealloc(C, C.getLocationContext(), SelfValOut);
970
1.60k
}
971
972
/// Returns true if LCtx is a call to -dealloc and false
973
/// otherwise. If true, it also sets SelfValOut to the value of
974
/// 'self'.
975
bool ObjCDeallocChecker::isInInstanceDealloc(const CheckerContext &C,
976
                                             const LocationContext *LCtx,
977
2.22k
                                             SVal &SelfValOut) const {
978
2.22k
  auto *MD = dyn_cast<ObjCMethodDecl>(LCtx->getDecl());
979
2.22k
  if (!MD || 
!MD->isInstanceMethod()1.58k
||
MD->getSelector() != DeallocSel1.53k
)
980
1.65k
    return false;
981
982
575
  const ImplicitParamDecl *SelfDecl = LCtx->getSelfDecl();
983
575
  assert(SelfDecl && "No self in -dealloc?");
984
985
575
  ProgramStateRef State = C.getState();
986
575
  SelfValOut = State->getSVal(State->getRegion(SelfDecl, LCtx));
987
575
  return true;
988
575
}
989
990
/// Returns true if there is a call to -dealloc anywhere on the stack and false
991
/// otherwise. If true, it also sets InstanceValOut to the value of
992
/// 'self' in the frame for -dealloc.
993
bool ObjCDeallocChecker::instanceDeallocIsOnStack(const CheckerContext &C,
994
592
                                                  SVal &InstanceValOut) const {
995
592
  const LocationContext *LCtx = C.getLocationContext();
996
997
972
  while (LCtx) {
998
620
    if (isInInstanceDealloc(C, LCtx, InstanceValOut))
999
240
      return true;
1000
1001
380
    LCtx = LCtx->getParent();
1002
380
  }
1003
1004
352
  return false;
1005
592
}
1006
1007
/// Returns true if the ID is a class in which which is known to have
1008
/// a separate teardown lifecycle. In this case, -dealloc warnings
1009
/// about missing releases should be suppressed.
1010
bool ObjCDeallocChecker::classHasSeparateTeardown(
1011
188
    const ObjCInterfaceDecl *ID) const {
1012
  // Suppress if the class is not a subclass of NSObject.
1013
399
  for ( ; ID ; 
ID = ID->getSuperClass()211
) {
1014
378
    IdentifierInfo *II = ID->getIdentifier();
1015
1016
378
    if (II == NSObjectII)
1017
154
      return false;
1018
1019
    // FIXME: For now, ignore classes that subclass SenTestCase and XCTestCase,
1020
    // as these don't need to implement -dealloc.  They implement tear down in
1021
    // another way, which we should try and catch later.
1022
    //  http://llvm.org/bugs/show_bug.cgi?id=3187
1023
224
    if (II == XCTestCaseII || 
II == SenTestCaseII218
)
1024
13
      return true;
1025
224
  }
1026
1027
21
  return true;
1028
188
}
1029
1030
/// The -dealloc method in CIFilter highly unusual in that is will release
1031
/// instance variables belonging to its *subclasses* if the variable name
1032
/// starts with "input" or backs a property whose name starts with "input".
1033
/// Subclasses should not release these ivars in their own -dealloc method --
1034
/// doing so could result in an over release.
1035
///
1036
/// This method returns true if the property will be released by
1037
/// -[CIFilter dealloc].
1038
bool ObjCDeallocChecker::isReleasedByCIFilterDealloc(
1039
236
    const ObjCPropertyImplDecl *PropImpl) const {
1040
236
  assert(PropImpl->getPropertyIvarDecl());
1041
236
  StringRef PropName = PropImpl->getPropertyDecl()->getName();
1042
236
  StringRef IvarName = PropImpl->getPropertyIvarDecl()->getName();
1043
1044
236
  const char *ReleasePrefix = "input";
1045
236
  if (!(PropName.startswith(ReleasePrefix) ||
1046
208
        IvarName.startswith(ReleasePrefix))) {
1047
204
    return false;
1048
204
  }
1049
1050
32
  const ObjCInterfaceDecl *ID =
1051
32
      PropImpl->getPropertyIvarDecl()->getContainingInterface();
1052
64
  for ( ; ID ; 
ID = ID->getSuperClass()32
) {
1053
64
    IdentifierInfo *II = ID->getIdentifier();
1054
64
    if (II == CIFilterII)
1055
32
      return true;
1056
64
  }
1057
1058
0
  return false;
1059
32
}
1060
1061
/// Returns whether the ivar backing the property is an IBOutlet that
1062
/// has its value set by nib loading code without retaining the value.
1063
///
1064
/// On macOS, if there is no setter, the nib-loading code sets the ivar
1065
/// directly, without retaining the value,
1066
///
1067
/// On iOS and its derivatives, the nib-loading code will call
1068
/// -setValue:forKey:, which retains the value before directly setting the ivar.
1069
bool ObjCDeallocChecker::isNibLoadedIvarWithoutRetain(
1070
201
    const ObjCPropertyImplDecl *PropImpl) const {
1071
201
  const ObjCIvarDecl *IvarDecl = PropImpl->getPropertyIvarDecl();
1072
201
  if (!IvarDecl->hasAttr<IBOutletAttr>())
1073
193
    return false;
1074
1075
8
  const llvm::Triple &Target =
1076
8
      IvarDecl->getASTContext().getTargetInfo().getTriple();
1077
1078
8
  if (!Target.isMacOSX())
1079
4
    return false;
1080
1081
4
  if (PropImpl->getPropertyDecl()->getSetterMethodDecl())
1082
2
    return false;
1083
1084
2
  return true;
1085
2
}
1086
1087
41
void ento::registerObjCDeallocChecker(CheckerManager &Mgr) {
1088
41
  Mgr.registerChecker<ObjCDeallocChecker>();
1089
41
}
1090
1091
90
bool ento::shouldRegisterObjCDeallocChecker(const CheckerManager &mgr) {
1092
  // These checker only makes sense under MRR.
1093
90
  const LangOptions &LO = mgr.getLangOpts();
1094
90
  return LO.getGC() != LangOptions::GCOnly && !LO.ObjCAutoRefCount;
1095
90
}