Consumed.cpp revision 52f717eba7eff69c97d64de5e3669f4a5ee57d5c 
1//===- Consumed.cpp --------------------------------------------*- C++ --*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// A intra-procedural analysis for checking consumed properties.  This is based,
11// in part, on research on linear types.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/AST/ASTContext.h"
16#include "clang/AST/Attr.h"
17#include "clang/AST/DeclCXX.h"
18#include "clang/AST/ExprCXX.h"
19#include "clang/AST/RecursiveASTVisitor.h"
20#include "clang/AST/StmtVisitor.h"
21#include "clang/AST/StmtCXX.h"
22#include "clang/AST/Type.h"
23#include "clang/Analysis/Analyses/PostOrderCFGView.h"
24#include "clang/Analysis/AnalysisContext.h"
25#include "clang/Analysis/CFG.h"
26#include "clang/Analysis/Analyses/Consumed.h"
27#include "clang/Basic/OperatorKinds.h"
28#include "clang/Basic/SourceLocation.h"
29#include "llvm/ADT/DenseMap.h"
30#include "llvm/ADT/SmallVector.h"
31#include "llvm/Support/Compiler.h"
32#include "llvm/Support/raw_ostream.h"
33
34// TODO: Use information from tests in while-loop conditional.
35// TODO: Add notes about the actual and expected state for
36// TODO: Correctly identify unreachable blocks when chaining boolean operators.
37// TODO: Adjust the parser and AttributesList class to support lists of
38//       identifiers.
39// TODO: Warn about unreachable code.
40// TODO: Switch to using a bitmap to track unreachable blocks.
41// TODO: Handle variable definitions, e.g. bool valid = x.isValid();
42//       if (valid) ...; (Deferred)
43// TODO: Take notes on state transitions to provide better warning messages.
44//       (Deferred)
45// TODO: Test nested conditionals: A) Checking the same value multiple times,
46//       and 2) Checking different values. (Deferred)
47
48using namespace clang;
49using namespace consumed;
50
51// Key method definition
52ConsumedWarningsHandlerBase::~ConsumedWarningsHandlerBase() {}
53
54static SourceLocation getFirstStmtLoc(const CFGBlock *Block) {
55  // Find the source location of the first statement in the block, if the block
56  // is not empty.
57  for (CFGBlock::const_iterator BI = Block->begin(), BE = Block->end();
58       BI != BE; ++BI) {
59    if (Optional<CFGStmt> CS = BI->getAs<CFGStmt>())
60      return CS->getStmt()->getLocStart();
61  }
62
63  // Block is empty.
64  // If we have one successor, return the first statement in that block
65  if (Block->succ_size() == 1 && *Block->succ_begin())
66    return getFirstStmtLoc(*Block->succ_begin());
67
68  return SourceLocation();
69}
70
71static SourceLocation getLastStmtLoc(const CFGBlock *Block) {
72  // Find the source location of the last statement in the block, if the block
73  // is not empty.
74  if (const Stmt *StmtNode = Block->getTerminator()) {
75    return StmtNode->getLocStart();
76  } else {
77    for (CFGBlock::const_reverse_iterator BI = Block->rbegin(),
78         BE = Block->rend(); BI != BE; ++BI) {
79      if (Optional<CFGStmt> CS = BI->getAs<CFGStmt>())
80        return CS->getStmt()->getLocStart();
81    }
82  }
83
84  // If we have one successor, return the first statement in that block
85  SourceLocation Loc;
86  if (Block->succ_size() == 1 && *Block->succ_begin())
87    Loc = getFirstStmtLoc(*Block->succ_begin());
88  if (Loc.isValid())
89    return Loc;
90
91  // If we have one predecessor, return the last statement in that block
92  if (Block->pred_size() == 1 && *Block->pred_begin())
93    return getLastStmtLoc(*Block->pred_begin());
94
95  return Loc;
96}
97
98static ConsumedState invertConsumedUnconsumed(ConsumedState State) {
99  switch (State) {
100  case CS_Unconsumed:
101    return CS_Consumed;
102  case CS_Consumed:
103    return CS_Unconsumed;
104  case CS_None:
105    return CS_None;
106  case CS_Unknown:
107    return CS_Unknown;
108  }
109  llvm_unreachable("invalid enum");
110}
111
112static bool isCallableInState(const CallableWhenAttr *CWAttr,
113                              ConsumedState State) {
114
115  CallableWhenAttr::callableState_iterator I = CWAttr->callableState_begin(),
116                                           E = CWAttr->callableState_end();
117
118  for (; I != E; ++I) {
119
120    ConsumedState MappedAttrState = CS_None;
121
122    switch (*I) {
123    case CallableWhenAttr::Unknown:
124      MappedAttrState = CS_Unknown;
125      break;
126
127    case CallableWhenAttr::Unconsumed:
128      MappedAttrState = CS_Unconsumed;
129      break;
130
131    case CallableWhenAttr::Consumed:
132      MappedAttrState = CS_Consumed;
133      break;
134    }
135
136    if (MappedAttrState == State)
137      return true;
138  }
139
140  return false;
141}
142
143static bool isConsumableType(const QualType &QT) {
144  if (const CXXRecordDecl *RD = QT->getAsCXXRecordDecl())
145    return RD->hasAttr<ConsumableAttr>();
146  else
147    return false;
148}
149
150static bool isKnownState(ConsumedState State) {
151  switch (State) {
152  case CS_Unconsumed:
153  case CS_Consumed:
154    return true;
155  case CS_None:
156  case CS_Unknown:
157    return false;
158  }
159  llvm_unreachable("invalid enum");
160}
161
162static bool isTestingFunction(const FunctionDecl *FunDecl) {
163  return FunDecl->hasAttr<TestsTypestateAttr>();
164}
165
166static ConsumedState mapConsumableAttrState(const QualType QT) {
167  assert(isConsumableType(QT));
168
169  const ConsumableAttr *CAttr =
170      QT->getAsCXXRecordDecl()->getAttr<ConsumableAttr>();
171
172  switch (CAttr->getDefaultState()) {
173  case ConsumableAttr::Unknown:
174    return CS_Unknown;
175  case ConsumableAttr::Unconsumed:
176    return CS_Unconsumed;
177  case ConsumableAttr::Consumed:
178    return CS_Consumed;
179  }
180  llvm_unreachable("invalid enum");
181}
182
183static ConsumedState mapSetTypestateAttrState(const SetTypestateAttr *STAttr) {
184  switch (STAttr->getNewState()) {
185  case SetTypestateAttr::Unknown:
186    return CS_Unknown;
187  case SetTypestateAttr::Unconsumed:
188    return CS_Unconsumed;
189  case SetTypestateAttr::Consumed:
190    return CS_Consumed;
191  }
192  llvm_unreachable("invalid_enum");
193}
194
195static ConsumedState
196mapReturnTypestateAttrState(const ReturnTypestateAttr *RTSAttr) {
197  switch (RTSAttr->getState()) {
198  case ReturnTypestateAttr::Unknown:
199    return CS_Unknown;
200  case ReturnTypestateAttr::Unconsumed:
201    return CS_Unconsumed;
202  case ReturnTypestateAttr::Consumed:
203    return CS_Consumed;
204  }
205  llvm_unreachable("invalid enum");
206}
207
208static StringRef stateToString(ConsumedState State) {
209  switch (State) {
210  case consumed::CS_None:
211    return "none";
212
213  case consumed::CS_Unknown:
214    return "unknown";
215
216  case consumed::CS_Unconsumed:
217    return "unconsumed";
218
219  case consumed::CS_Consumed:
220    return "consumed";
221  }
222  llvm_unreachable("invalid enum");
223}
224
225static ConsumedState testsFor(const FunctionDecl *FunDecl) {
226  assert(isTestingFunction(FunDecl));
227  switch (FunDecl->getAttr<TestsTypestateAttr>()->getTestState()) {
228  case TestsTypestateAttr::Unconsumed:
229    return CS_Unconsumed;
230  case TestsTypestateAttr::Consumed:
231    return CS_Consumed;
232  }
233  llvm_unreachable("invalid enum");
234}
235
236namespace {
237struct VarTestResult {
238  const VarDecl *Var;
239  ConsumedState TestsFor;
240};
241} // end anonymous::VarTestResult
242
243namespace clang {
244namespace consumed {
245
246enum EffectiveOp {
247  EO_And,
248  EO_Or
249};
250
251class PropagationInfo {
252  enum {
253    IT_None,
254    IT_State,
255    IT_Test,
256    IT_BinTest,
257    IT_Var
258  } InfoType;
259
260  struct BinTestTy {
261    const BinaryOperator *Source;
262    EffectiveOp EOp;
263    VarTestResult LTest;
264    VarTestResult RTest;
265  };
266
267  union {
268    ConsumedState State;
269    VarTestResult Test;
270    const VarDecl *Var;
271    BinTestTy BinTest;
272  };
273
274  QualType TempType;
275
276public:
277  PropagationInfo() : InfoType(IT_None) {}
278
279  PropagationInfo(const VarTestResult &Test) : InfoType(IT_Test), Test(Test) {}
280  PropagationInfo(const VarDecl *Var, ConsumedState TestsFor)
281    : InfoType(IT_Test) {
282
283    Test.Var      = Var;
284    Test.TestsFor = TestsFor;
285  }
286
287  PropagationInfo(const BinaryOperator *Source, EffectiveOp EOp,
288                  const VarTestResult &LTest, const VarTestResult &RTest)
289    : InfoType(IT_BinTest) {
290
291    BinTest.Source  = Source;
292    BinTest.EOp     = EOp;
293    BinTest.LTest   = LTest;
294    BinTest.RTest   = RTest;
295  }
296
297  PropagationInfo(const BinaryOperator *Source, EffectiveOp EOp,
298                  const VarDecl *LVar, ConsumedState LTestsFor,
299                  const VarDecl *RVar, ConsumedState RTestsFor)
300    : InfoType(IT_BinTest) {
301
302    BinTest.Source         = Source;
303    BinTest.EOp            = EOp;
304    BinTest.LTest.Var      = LVar;
305    BinTest.LTest.TestsFor = LTestsFor;
306    BinTest.RTest.Var      = RVar;
307    BinTest.RTest.TestsFor = RTestsFor;
308  }
309
310  PropagationInfo(ConsumedState State, QualType TempType)
311    : InfoType(IT_State), State(State), TempType(TempType) {}
312
313  PropagationInfo(const VarDecl *Var) : InfoType(IT_Var), Var(Var) {}
314
315  const ConsumedState & getState() const {
316    assert(InfoType == IT_State);
317    return State;
318  }
319
320  const QualType & getTempType() const {
321    assert(InfoType == IT_State);
322    return TempType;
323  }
324
325  const VarTestResult & getTest() const {
326    assert(InfoType == IT_Test);
327    return Test;
328  }
329
330  const VarTestResult & getLTest() const {
331    assert(InfoType == IT_BinTest);
332    return BinTest.LTest;
333  }
334
335  const VarTestResult & getRTest() const {
336    assert(InfoType == IT_BinTest);
337    return BinTest.RTest;
338  }
339
340  const VarDecl * getVar() const {
341    assert(InfoType == IT_Var);
342    return Var;
343  }
344
345  EffectiveOp testEffectiveOp() const {
346    assert(InfoType == IT_BinTest);
347    return BinTest.EOp;
348  }
349
350  const BinaryOperator * testSourceNode() const {
351    assert(InfoType == IT_BinTest);
352    return BinTest.Source;
353  }
354
355  bool isValid()   const { return InfoType != IT_None;     }
356  bool isState()   const { return InfoType == IT_State;    }
357  bool isTest()    const { return InfoType == IT_Test;     }
358  bool isBinTest() const { return InfoType == IT_BinTest;  }
359  bool isVar()     const { return InfoType == IT_Var;      }
360
361  PropagationInfo invertTest() const {
362    assert(InfoType == IT_Test || InfoType == IT_BinTest);
363
364    if (InfoType == IT_Test) {
365      return PropagationInfo(Test.Var, invertConsumedUnconsumed(Test.TestsFor));
366
367    } else if (InfoType == IT_BinTest) {
368      return PropagationInfo(BinTest.Source,
369        BinTest.EOp == EO_And ? EO_Or : EO_And,
370        BinTest.LTest.Var, invertConsumedUnconsumed(BinTest.LTest.TestsFor),
371        BinTest.RTest.Var, invertConsumedUnconsumed(BinTest.RTest.TestsFor));
372    } else {
373      return PropagationInfo();
374    }
375  }
376};
377
378class ConsumedStmtVisitor : public ConstStmtVisitor<ConsumedStmtVisitor> {
379
380  typedef llvm::DenseMap<const Stmt *, PropagationInfo> MapType;
381  typedef std::pair<const Stmt *, PropagationInfo> PairType;
382  typedef MapType::iterator InfoEntry;
383  typedef MapType::const_iterator ConstInfoEntry;
384
385  AnalysisDeclContext &AC;
386  ConsumedAnalyzer &Analyzer;
387  ConsumedStateMap *StateMap;
388  MapType PropagationMap;
389  void forwardInfo(const Stmt *From, const Stmt *To);
390  bool isLikeMoveAssignment(const CXXMethodDecl *MethodDecl);
391  void propagateReturnType(const Stmt *Call, const FunctionDecl *Fun,
392                           QualType ReturnType);
393
394public:
395  void checkCallability(const PropagationInfo &PInfo,
396                        const FunctionDecl *FunDecl,
397                        SourceLocation BlameLoc);
398
399  void Visit(const Stmt *StmtNode);
400
401  void VisitBinaryOperator(const BinaryOperator *BinOp);
402  void VisitCallExpr(const CallExpr *Call);
403  void VisitCastExpr(const CastExpr *Cast);
404  void VisitCXXBindTemporaryExpr(const CXXBindTemporaryExpr *Temp);
405  void VisitCXXConstructExpr(const CXXConstructExpr *Call);
406  void VisitCXXMemberCallExpr(const CXXMemberCallExpr *Call);
407  void VisitCXXOperatorCallExpr(const CXXOperatorCallExpr *Call);
408  void VisitDeclRefExpr(const DeclRefExpr *DeclRef);
409  void VisitDeclStmt(const DeclStmt *DelcS);
410  void VisitMaterializeTemporaryExpr(const MaterializeTemporaryExpr *Temp);
411  void VisitMemberExpr(const MemberExpr *MExpr);
412  void VisitParmVarDecl(const ParmVarDecl *Param);
413  void VisitReturnStmt(const ReturnStmt *Ret);
414  void VisitUnaryOperator(const UnaryOperator *UOp);
415  void VisitVarDecl(const VarDecl *Var);
416
417  ConsumedStmtVisitor(AnalysisDeclContext &AC, ConsumedAnalyzer &Analyzer,
418                      ConsumedStateMap *StateMap)
419      : AC(AC), Analyzer(Analyzer), StateMap(StateMap) {}
420
421  PropagationInfo getInfo(const Stmt *StmtNode) const {
422    ConstInfoEntry Entry = PropagationMap.find(StmtNode);
423
424    if (Entry != PropagationMap.end())
425      return Entry->second;
426    else
427      return PropagationInfo();
428  }
429
430  void reset(ConsumedStateMap *NewStateMap) {
431    StateMap = NewStateMap;
432  }
433};
434
435void ConsumedStmtVisitor::checkCallability(const PropagationInfo &PInfo,
436                                           const FunctionDecl *FunDecl,
437                                           SourceLocation BlameLoc) {
438
439  if (!FunDecl->hasAttr<CallableWhenAttr>())
440    return;
441
442  const CallableWhenAttr *CWAttr = FunDecl->getAttr<CallableWhenAttr>();
443
444  if (PInfo.isVar()) {
445    const VarDecl *Var = PInfo.getVar();
446    ConsumedState VarState = StateMap->getState(Var);
447
448    assert(VarState != CS_None && "Invalid state");
449
450    if (isCallableInState(CWAttr, VarState))
451      return;
452
453    Analyzer.WarningsHandler.warnUseInInvalidState(
454      FunDecl->getNameAsString(), Var->getNameAsString(),
455      stateToString(VarState), BlameLoc);
456
457  } else if (PInfo.isState()) {
458
459    assert(PInfo.getState() != CS_None && "Invalid state");
460
461    if (isCallableInState(CWAttr, PInfo.getState()))
462      return;
463
464    Analyzer.WarningsHandler.warnUseOfTempInInvalidState(
465      FunDecl->getNameAsString(), stateToString(PInfo.getState()), BlameLoc);
466  }
467}
468
469void ConsumedStmtVisitor::forwardInfo(const Stmt *From, const Stmt *To) {
470  InfoEntry Entry = PropagationMap.find(From);
471
472  if (Entry != PropagationMap.end())
473    PropagationMap.insert(PairType(To, Entry->second));
474}
475
476bool ConsumedStmtVisitor::isLikeMoveAssignment(
477  const CXXMethodDecl *MethodDecl) {
478
479  return MethodDecl->isMoveAssignmentOperator() ||
480         (MethodDecl->getOverloadedOperator() == OO_Equal &&
481          MethodDecl->getNumParams() == 1 &&
482          MethodDecl->getParamDecl(0)->getType()->isRValueReferenceType());
483}
484
485void ConsumedStmtVisitor::propagateReturnType(const Stmt *Call,
486                                              const FunctionDecl *Fun,
487                                              QualType ReturnType) {
488  if (isConsumableType(ReturnType)) {
489
490    ConsumedState ReturnState;
491
492    if (Fun->hasAttr<ReturnTypestateAttr>())
493      ReturnState = mapReturnTypestateAttrState(
494        Fun->getAttr<ReturnTypestateAttr>());
495    else
496      ReturnState = mapConsumableAttrState(ReturnType);
497
498    PropagationMap.insert(PairType(Call,
499      PropagationInfo(ReturnState, ReturnType)));
500  }
501}
502
503void ConsumedStmtVisitor::Visit(const Stmt *StmtNode) {
504
505  ConstStmtVisitor<ConsumedStmtVisitor>::Visit(StmtNode);
506
507  for (Stmt::const_child_iterator CI = StmtNode->child_begin(),
508       CE = StmtNode->child_end(); CI != CE; ++CI) {
509
510    PropagationMap.erase(*CI);
511  }
512}
513
514void ConsumedStmtVisitor::VisitBinaryOperator(const BinaryOperator *BinOp) {
515  switch (BinOp->getOpcode()) {
516  case BO_LAnd:
517  case BO_LOr : {
518    InfoEntry LEntry = PropagationMap.find(BinOp->getLHS()),
519              REntry = PropagationMap.find(BinOp->getRHS());
520
521    VarTestResult LTest, RTest;
522
523    if (LEntry != PropagationMap.end() && LEntry->second.isTest()) {
524      LTest = LEntry->second.getTest();
525
526    } else {
527      LTest.Var      = NULL;
528      LTest.TestsFor = CS_None;
529    }
530
531    if (REntry != PropagationMap.end() && REntry->second.isTest()) {
532      RTest = REntry->second.getTest();
533
534    } else {
535      RTest.Var      = NULL;
536      RTest.TestsFor = CS_None;
537    }
538
539    if (!(LTest.Var == NULL && RTest.Var == NULL))
540      PropagationMap.insert(PairType(BinOp, PropagationInfo(BinOp,
541        static_cast<EffectiveOp>(BinOp->getOpcode() == BO_LOr), LTest, RTest)));
542
543    break;
544  }
545
546  case BO_PtrMemD:
547  case BO_PtrMemI:
548    forwardInfo(BinOp->getLHS(), BinOp);
549    break;
550
551  default:
552    break;
553  }
554}
555
556void ConsumedStmtVisitor::VisitCallExpr(const CallExpr *Call) {
557  if (const FunctionDecl *FunDecl =
558    dyn_cast_or_null<FunctionDecl>(Call->getDirectCallee())) {
559
560    // Special case for the std::move function.
561    // TODO: Make this more specific. (Deferred)
562    if (FunDecl->getNameAsString() == "move") {
563      InfoEntry Entry = PropagationMap.find(Call->getArg(0));
564
565      if (Entry != PropagationMap.end()) {
566        PropagationMap.insert(PairType(Call, Entry->second));
567      }
568
569      return;
570    }
571
572    unsigned Offset = Call->getNumArgs() - FunDecl->getNumParams();
573
574    for (unsigned Index = Offset; Index < Call->getNumArgs(); ++Index) {
575      QualType ParamType = FunDecl->getParamDecl(Index - Offset)->getType();
576
577      InfoEntry Entry = PropagationMap.find(Call->getArg(Index));
578
579      if (Entry == PropagationMap.end() || !Entry->second.isVar()) {
580        continue;
581      }
582
583      PropagationInfo PInfo = Entry->second;
584
585      if (ParamType->isRValueReferenceType() ||
586          (ParamType->isLValueReferenceType() &&
587           !cast<LValueReferenceType>(*ParamType).isSpelledAsLValue())) {
588
589        StateMap->setState(PInfo.getVar(), consumed::CS_Consumed);
590
591      } else if (!(ParamType.isConstQualified() ||
592                   ((ParamType->isReferenceType() ||
593                     ParamType->isPointerType()) &&
594                    ParamType->getPointeeType().isConstQualified()))) {
595
596        StateMap->setState(PInfo.getVar(), consumed::CS_Unknown);
597      }
598    }
599
600    QualType RetType = FunDecl->getCallResultType();
601    if (RetType->isReferenceType())
602      RetType = RetType->getPointeeType();
603
604    propagateReturnType(Call, FunDecl, RetType);
605  }
606}
607
608void ConsumedStmtVisitor::VisitCastExpr(const CastExpr *Cast) {
609  forwardInfo(Cast->getSubExpr(), Cast);
610}
611
612void ConsumedStmtVisitor::VisitCXXBindTemporaryExpr(
613  const CXXBindTemporaryExpr *Temp) {
614
615  forwardInfo(Temp->getSubExpr(), Temp);
616}
617
618void ConsumedStmtVisitor::VisitCXXConstructExpr(const CXXConstructExpr *Call) {
619  CXXConstructorDecl *Constructor = Call->getConstructor();
620
621  ASTContext &CurrContext = AC.getASTContext();
622  QualType ThisType = Constructor->getThisType(CurrContext)->getPointeeType();
623
624  if (isConsumableType(ThisType)) {
625    if (Constructor->isDefaultConstructor()) {
626
627      PropagationMap.insert(PairType(Call,
628        PropagationInfo(consumed::CS_Consumed, ThisType)));
629
630    } else if (Constructor->isMoveConstructor()) {
631
632      PropagationInfo PInfo =
633        PropagationMap.find(Call->getArg(0))->second;
634
635      if (PInfo.isVar()) {
636        const VarDecl* Var = PInfo.getVar();
637
638        PropagationMap.insert(PairType(Call,
639          PropagationInfo(StateMap->getState(Var), ThisType)));
640
641        StateMap->setState(Var, consumed::CS_Consumed);
642
643      } else {
644        PropagationMap.insert(PairType(Call, PInfo));
645      }
646
647    } else if (Constructor->isCopyConstructor()) {
648      MapType::iterator Entry = PropagationMap.find(Call->getArg(0));
649
650      if (Entry != PropagationMap.end())
651        PropagationMap.insert(PairType(Call, Entry->second));
652
653    } else {
654      propagateReturnType(Call, Constructor, ThisType);
655    }
656  }
657}
658
659
660void ConsumedStmtVisitor::VisitCXXMemberCallExpr(
661  const CXXMemberCallExpr *Call) {
662
663  VisitCallExpr(Call);
664
665  InfoEntry Entry = PropagationMap.find(Call->getCallee()->IgnoreParens());
666
667  if (Entry != PropagationMap.end()) {
668    PropagationInfo PInfo = Entry->second;
669    const CXXMethodDecl *MethodDecl = Call->getMethodDecl();
670
671    checkCallability(PInfo, MethodDecl, Call->getExprLoc());
672
673    if (PInfo.isVar()) {
674      if (isTestingFunction(MethodDecl))
675        PropagationMap.insert(PairType(Call,
676          PropagationInfo(PInfo.getVar(), testsFor(MethodDecl))));
677      else if (MethodDecl->hasAttr<SetTypestateAttr>())
678        StateMap->setState(PInfo.getVar(),
679          mapSetTypestateAttrState(MethodDecl->getAttr<SetTypestateAttr>()));
680    }
681  }
682}
683
684void ConsumedStmtVisitor::VisitCXXOperatorCallExpr(
685  const CXXOperatorCallExpr *Call) {
686
687  const FunctionDecl *FunDecl =
688    dyn_cast_or_null<FunctionDecl>(Call->getDirectCallee());
689
690  if (!FunDecl) return;
691
692  if (isa<CXXMethodDecl>(FunDecl) &&
693      isLikeMoveAssignment(cast<CXXMethodDecl>(FunDecl))) {
694
695    InfoEntry LEntry = PropagationMap.find(Call->getArg(0));
696    InfoEntry REntry = PropagationMap.find(Call->getArg(1));
697
698    PropagationInfo LPInfo, RPInfo;
699
700    if (LEntry != PropagationMap.end() &&
701        REntry != PropagationMap.end()) {
702
703      LPInfo = LEntry->second;
704      RPInfo = REntry->second;
705
706      if (LPInfo.isVar() && RPInfo.isVar()) {
707        StateMap->setState(LPInfo.getVar(),
708          StateMap->getState(RPInfo.getVar()));
709
710        StateMap->setState(RPInfo.getVar(), consumed::CS_Consumed);
711
712        PropagationMap.insert(PairType(Call, LPInfo));
713
714      } else if (LPInfo.isVar() && !RPInfo.isVar()) {
715        StateMap->setState(LPInfo.getVar(), RPInfo.getState());
716
717        PropagationMap.insert(PairType(Call, LPInfo));
718
719      } else if (!LPInfo.isVar() && RPInfo.isVar()) {
720        PropagationMap.insert(PairType(Call,
721          PropagationInfo(StateMap->getState(RPInfo.getVar()),
722                          LPInfo.getTempType())));
723
724        StateMap->setState(RPInfo.getVar(), consumed::CS_Consumed);
725
726      } else {
727        PropagationMap.insert(PairType(Call, RPInfo));
728      }
729
730    } else if (LEntry != PropagationMap.end() &&
731               REntry == PropagationMap.end()) {
732
733      LPInfo = LEntry->second;
734
735      if (LPInfo.isVar()) {
736        StateMap->setState(LPInfo.getVar(), consumed::CS_Unknown);
737
738        PropagationMap.insert(PairType(Call, LPInfo));
739
740      } else if (LPInfo.isState()) {
741        PropagationMap.insert(PairType(Call,
742          PropagationInfo(consumed::CS_Unknown, LPInfo.getTempType())));
743      }
744
745    } else if (LEntry == PropagationMap.end() &&
746               REntry != PropagationMap.end()) {
747
748      if (REntry->second.isVar())
749        StateMap->setState(REntry->second.getVar(), consumed::CS_Consumed);
750    }
751
752  } else {
753
754    VisitCallExpr(Call);
755
756    InfoEntry Entry = PropagationMap.find(Call->getArg(0));
757
758    if (Entry != PropagationMap.end()) {
759      PropagationInfo PInfo = Entry->second;
760
761      checkCallability(PInfo, FunDecl, Call->getExprLoc());
762
763      if (PInfo.isVar()) {
764        if (isTestingFunction(FunDecl))
765          PropagationMap.insert(PairType(Call,
766            PropagationInfo(PInfo.getVar(), testsFor(FunDecl))));
767        else if (FunDecl->hasAttr<SetTypestateAttr>())
768          StateMap->setState(PInfo.getVar(),
769            mapSetTypestateAttrState(FunDecl->getAttr<SetTypestateAttr>()));
770      }
771    }
772  }
773}
774
775void ConsumedStmtVisitor::VisitDeclRefExpr(const DeclRefExpr *DeclRef) {
776  if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(DeclRef->getDecl()))
777    if (StateMap->getState(Var) != consumed::CS_None)
778      PropagationMap.insert(PairType(DeclRef, PropagationInfo(Var)));
779}
780
781void ConsumedStmtVisitor::VisitDeclStmt(const DeclStmt *DeclS) {
782  for (DeclStmt::const_decl_iterator DI = DeclS->decl_begin(),
783       DE = DeclS->decl_end(); DI != DE; ++DI) {
784
785    if (isa<VarDecl>(*DI)) VisitVarDecl(cast<VarDecl>(*DI));
786  }
787
788  if (DeclS->isSingleDecl())
789    if (const VarDecl *Var = dyn_cast_or_null<VarDecl>(DeclS->getSingleDecl()))
790      PropagationMap.insert(PairType(DeclS, PropagationInfo(Var)));
791}
792
793void ConsumedStmtVisitor::VisitMaterializeTemporaryExpr(
794  const MaterializeTemporaryExpr *Temp) {
795
796  InfoEntry Entry = PropagationMap.find(Temp->GetTemporaryExpr());
797
798  if (Entry != PropagationMap.end())
799    PropagationMap.insert(PairType(Temp, Entry->second));
800}
801
802void ConsumedStmtVisitor::VisitMemberExpr(const MemberExpr *MExpr) {
803  forwardInfo(MExpr->getBase(), MExpr);
804}
805
806
807void ConsumedStmtVisitor::VisitParmVarDecl(const ParmVarDecl *Param) {
808  QualType ParamType = Param->getType();
809  ConsumedState ParamState = consumed::CS_None;
810
811  if (!(ParamType->isPointerType() || ParamType->isReferenceType()) &&
812      isConsumableType(ParamType))
813    ParamState = mapConsumableAttrState(ParamType);
814  else if (ParamType->isReferenceType() &&
815           isConsumableType(ParamType->getPointeeType()))
816    ParamState = consumed::CS_Unknown;
817
818  if (ParamState)
819    StateMap->setState(Param, ParamState);
820}
821
822void ConsumedStmtVisitor::VisitReturnStmt(const ReturnStmt *Ret) {
823  if (ConsumedState ExpectedState = Analyzer.getExpectedReturnState()) {
824    InfoEntry Entry = PropagationMap.find(Ret->getRetValue());
825
826    if (Entry != PropagationMap.end()) {
827      assert(Entry->second.isState() || Entry->second.isVar());
828
829      ConsumedState RetState = Entry->second.isState() ?
830        Entry->second.getState() : StateMap->getState(Entry->second.getVar());
831
832      if (RetState != ExpectedState)
833        Analyzer.WarningsHandler.warnReturnTypestateMismatch(
834          Ret->getReturnLoc(), stateToString(ExpectedState),
835          stateToString(RetState));
836    }
837  }
838}
839
840void ConsumedStmtVisitor::VisitUnaryOperator(const UnaryOperator *UOp) {
841  InfoEntry Entry = PropagationMap.find(UOp->getSubExpr()->IgnoreParens());
842  if (Entry == PropagationMap.end()) return;
843
844  switch (UOp->getOpcode()) {
845  case UO_AddrOf:
846    PropagationMap.insert(PairType(UOp, Entry->second));
847    break;
848
849  case UO_LNot:
850    if (Entry->second.isTest() || Entry->second.isBinTest())
851      PropagationMap.insert(PairType(UOp, Entry->second.invertTest()));
852    break;
853
854  default:
855    break;
856  }
857}
858
859// TODO: See if I need to check for reference types here.
860void ConsumedStmtVisitor::VisitVarDecl(const VarDecl *Var) {
861  if (isConsumableType(Var->getType())) {
862    if (Var->hasInit()) {
863      PropagationInfo PInfo =
864        PropagationMap.find(Var->getInit())->second;
865
866      StateMap->setState(Var, PInfo.isVar() ?
867        StateMap->getState(PInfo.getVar()) : PInfo.getState());
868
869    } else {
870      StateMap->setState(Var, consumed::CS_Unknown);
871    }
872  }
873}
874}} // end clang::consumed::ConsumedStmtVisitor
875
876namespace clang {
877namespace consumed {
878
879void splitVarStateForIf(const IfStmt * IfNode, const VarTestResult &Test,
880                        ConsumedStateMap *ThenStates,
881                        ConsumedStateMap *ElseStates) {
882
883  ConsumedState VarState = ThenStates->getState(Test.Var);
884
885  if (VarState == CS_Unknown) {
886    ThenStates->setState(Test.Var, Test.TestsFor);
887    ElseStates->setState(Test.Var, invertConsumedUnconsumed(Test.TestsFor));
888
889  } else if (VarState == invertConsumedUnconsumed(Test.TestsFor)) {
890    ThenStates->markUnreachable();
891
892  } else if (VarState == Test.TestsFor) {
893    ElseStates->markUnreachable();
894  }
895}
896
897void splitVarStateForIfBinOp(const PropagationInfo &PInfo,
898  ConsumedStateMap *ThenStates, ConsumedStateMap *ElseStates) {
899
900  const VarTestResult &LTest = PInfo.getLTest(),
901                      &RTest = PInfo.getRTest();
902
903  ConsumedState LState = LTest.Var ? ThenStates->getState(LTest.Var) : CS_None,
904                RState = RTest.Var ? ThenStates->getState(RTest.Var) : CS_None;
905
906  if (LTest.Var) {
907    if (PInfo.testEffectiveOp() == EO_And) {
908      if (LState == CS_Unknown) {
909        ThenStates->setState(LTest.Var, LTest.TestsFor);
910
911      } else if (LState == invertConsumedUnconsumed(LTest.TestsFor)) {
912        ThenStates->markUnreachable();
913
914      } else if (LState == LTest.TestsFor && isKnownState(RState)) {
915        if (RState == RTest.TestsFor)
916          ElseStates->markUnreachable();
917        else
918          ThenStates->markUnreachable();
919      }
920
921    } else {
922      if (LState == CS_Unknown) {
923        ElseStates->setState(LTest.Var,
924                             invertConsumedUnconsumed(LTest.TestsFor));
925
926      } else if (LState == LTest.TestsFor) {
927        ElseStates->markUnreachable();
928
929      } else if (LState == invertConsumedUnconsumed(LTest.TestsFor) &&
930                 isKnownState(RState)) {
931
932        if (RState == RTest.TestsFor)
933          ElseStates->markUnreachable();
934        else
935          ThenStates->markUnreachable();
936      }
937    }
938  }
939
940  if (RTest.Var) {
941    if (PInfo.testEffectiveOp() == EO_And) {
942      if (RState == CS_Unknown)
943        ThenStates->setState(RTest.Var, RTest.TestsFor);
944      else if (RState == invertConsumedUnconsumed(RTest.TestsFor))
945        ThenStates->markUnreachable();
946
947    } else {
948      if (RState == CS_Unknown)
949        ElseStates->setState(RTest.Var,
950                             invertConsumedUnconsumed(RTest.TestsFor));
951      else if (RState == RTest.TestsFor)
952        ElseStates->markUnreachable();
953    }
954  }
955}
956
957bool ConsumedBlockInfo::allBackEdgesVisited(const CFGBlock *CurrBlock,
958                                            const CFGBlock *TargetBlock) {
959
960  assert(CurrBlock && "Block pointer must not be NULL");
961  assert(TargetBlock && "TargetBlock pointer must not be NULL");
962
963  unsigned int CurrBlockOrder = VisitOrder[CurrBlock->getBlockID()];
964  for (CFGBlock::const_pred_iterator PI = TargetBlock->pred_begin(),
965       PE = TargetBlock->pred_end(); PI != PE; ++PI) {
966    if (*PI && CurrBlockOrder < VisitOrder[(*PI)->getBlockID()] )
967      return false;
968  }
969  return true;
970}
971
972void ConsumedBlockInfo::addInfo(const CFGBlock *Block,
973                                ConsumedStateMap *StateMap,
974                                bool &AlreadyOwned) {
975
976  assert(Block && "Block pointer must not be NULL");
977
978  ConsumedStateMap *Entry = StateMapsArray[Block->getBlockID()];
979
980  if (Entry) {
981    Entry->intersect(StateMap);
982
983  } else if (AlreadyOwned) {
984    StateMapsArray[Block->getBlockID()] = new ConsumedStateMap(*StateMap);
985
986  } else {
987    StateMapsArray[Block->getBlockID()] = StateMap;
988    AlreadyOwned = true;
989  }
990}
991
992void ConsumedBlockInfo::addInfo(const CFGBlock *Block,
993                                ConsumedStateMap *StateMap) {
994
995  assert(Block != NULL && "Block pointer must not be NULL");
996
997  ConsumedStateMap *Entry = StateMapsArray[Block->getBlockID()];
998
999  if (Entry) {
1000    Entry->intersect(StateMap);
1001    delete StateMap;
1002
1003  } else {
1004    StateMapsArray[Block->getBlockID()] = StateMap;
1005  }
1006}
1007
1008ConsumedStateMap* ConsumedBlockInfo::borrowInfo(const CFGBlock *Block) {
1009  assert(Block && "Block pointer must not be NULL");
1010  assert(StateMapsArray[Block->getBlockID()] && "Block has no block info");
1011
1012  return StateMapsArray[Block->getBlockID()];
1013}
1014
1015void ConsumedBlockInfo::discardInfo(const CFGBlock *Block) {
1016  unsigned int BlockID = Block->getBlockID();
1017  delete StateMapsArray[BlockID];
1018  StateMapsArray[BlockID] = NULL;
1019}
1020
1021ConsumedStateMap* ConsumedBlockInfo::getInfo(const CFGBlock *Block) {
1022  assert(Block && "Block pointer must not be NULL");
1023
1024  ConsumedStateMap *StateMap = StateMapsArray[Block->getBlockID()];
1025  if (isBackEdgeTarget(Block)) {
1026    return new ConsumedStateMap(*StateMap);
1027  } else {
1028    StateMapsArray[Block->getBlockID()] = NULL;
1029    return StateMap;
1030  }
1031}
1032
1033bool ConsumedBlockInfo::isBackEdge(const CFGBlock *From, const CFGBlock *To) {
1034  assert(From && "From block must not be NULL");
1035  assert(To   && "From block must not be NULL");
1036
1037  return VisitOrder[From->getBlockID()] > VisitOrder[To->getBlockID()];
1038}
1039
1040bool ConsumedBlockInfo::isBackEdgeTarget(const CFGBlock *Block) {
1041  assert(Block != NULL && "Block pointer must not be NULL");
1042
1043  // Anything with less than two predecessors can't be the target of a back
1044  // edge.
1045  if (Block->pred_size() < 2)
1046    return false;
1047
1048  unsigned int BlockVisitOrder = VisitOrder[Block->getBlockID()];
1049  for (CFGBlock::const_pred_iterator PI = Block->pred_begin(),
1050       PE = Block->pred_end(); PI != PE; ++PI) {
1051    if (*PI && BlockVisitOrder < VisitOrder[(*PI)->getBlockID()])
1052      return true;
1053  }
1054  return false;
1055}
1056
1057ConsumedState ConsumedStateMap::getState(const VarDecl *Var) const {
1058  MapType::const_iterator Entry = Map.find(Var);
1059
1060  if (Entry != Map.end()) {
1061    return Entry->second;
1062
1063  } else {
1064    return CS_None;
1065  }
1066}
1067
1068void ConsumedStateMap::intersect(const ConsumedStateMap *Other) {
1069  ConsumedState LocalState;
1070
1071  if (this->From && this->From == Other->From && !Other->Reachable) {
1072    this->markUnreachable();
1073    return;
1074  }
1075
1076  for (MapType::const_iterator DMI = Other->Map.begin(), DME = Other->Map.end();
1077       DMI != DME; ++DMI) {
1078
1079    LocalState = this->getState(DMI->first);
1080
1081    if (LocalState == CS_None)
1082      continue;
1083
1084    if (LocalState != DMI->second)
1085       Map[DMI->first] = CS_Unknown;
1086  }
1087}
1088
1089void ConsumedStateMap::intersectAtLoopHead(const CFGBlock *LoopHead,
1090  const CFGBlock *LoopBack, const ConsumedStateMap *LoopBackStates,
1091  ConsumedWarningsHandlerBase &WarningsHandler) {
1092
1093  ConsumedState LocalState;
1094  SourceLocation BlameLoc = getLastStmtLoc(LoopBack);
1095
1096  for (MapType::const_iterator DMI = LoopBackStates->Map.begin(),
1097       DME = LoopBackStates->Map.end(); DMI != DME; ++DMI) {
1098
1099    LocalState = this->getState(DMI->first);
1100
1101    if (LocalState == CS_None)
1102      continue;
1103
1104    if (LocalState != DMI->second) {
1105      Map[DMI->first] = CS_Unknown;
1106      WarningsHandler.warnLoopStateMismatch(
1107        BlameLoc, DMI->first->getNameAsString());
1108    }
1109  }
1110}
1111
1112void ConsumedStateMap::markUnreachable() {
1113  this->Reachable = false;
1114  Map.clear();
1115}
1116
1117void ConsumedStateMap::setState(const VarDecl *Var, ConsumedState State) {
1118  Map[Var] = State;
1119}
1120
1121void ConsumedStateMap::remove(const VarDecl *Var) {
1122  Map.erase(Var);
1123}
1124
1125bool ConsumedStateMap::operator!=(const ConsumedStateMap *Other) const {
1126  for (MapType::const_iterator DMI = Other->Map.begin(), DME = Other->Map.end();
1127       DMI != DME; ++DMI) {
1128
1129    if (this->getState(DMI->first) != DMI->second)
1130      return true;
1131  }
1132
1133  return false;
1134}
1135
1136void ConsumedAnalyzer::determineExpectedReturnState(AnalysisDeclContext &AC,
1137                                                    const FunctionDecl *D) {
1138  QualType ReturnType;
1139  if (const CXXConstructorDecl *Constructor = dyn_cast<CXXConstructorDecl>(D)) {
1140    ASTContext &CurrContext = AC.getASTContext();
1141    ReturnType = Constructor->getThisType(CurrContext)->getPointeeType();
1142  } else
1143    ReturnType = D->getCallResultType();
1144
1145  if (D->hasAttr<ReturnTypestateAttr>()) {
1146    const ReturnTypestateAttr *RTSAttr = D->getAttr<ReturnTypestateAttr>();
1147
1148    const CXXRecordDecl *RD = ReturnType->getAsCXXRecordDecl();
1149    if (!RD || !RD->hasAttr<ConsumableAttr>()) {
1150      // FIXME: This should be removed when template instantiation propagates
1151      //        attributes at template specialization definition, not
1152      //        declaration. When it is removed the test needs to be enabled
1153      //        in SemaDeclAttr.cpp.
1154      WarningsHandler.warnReturnTypestateForUnconsumableType(
1155          RTSAttr->getLocation(), ReturnType.getAsString());
1156      ExpectedReturnState = CS_None;
1157    } else
1158      ExpectedReturnState = mapReturnTypestateAttrState(RTSAttr);
1159  } else if (isConsumableType(ReturnType))
1160    ExpectedReturnState = mapConsumableAttrState(ReturnType);
1161  else
1162    ExpectedReturnState = CS_None;
1163}
1164
1165bool ConsumedAnalyzer::splitState(const CFGBlock *CurrBlock,
1166                                  const ConsumedStmtVisitor &Visitor) {
1167
1168  ConsumedStateMap *FalseStates = new ConsumedStateMap(*CurrStates);
1169  PropagationInfo PInfo;
1170
1171  if (const IfStmt *IfNode =
1172    dyn_cast_or_null<IfStmt>(CurrBlock->getTerminator().getStmt())) {
1173
1174    const Stmt *Cond = IfNode->getCond();
1175
1176    PInfo = Visitor.getInfo(Cond);
1177    if (!PInfo.isValid() && isa<BinaryOperator>(Cond))
1178      PInfo = Visitor.getInfo(cast<BinaryOperator>(Cond)->getRHS());
1179
1180    if (PInfo.isTest()) {
1181      CurrStates->setSource(Cond);
1182      FalseStates->setSource(Cond);
1183      splitVarStateForIf(IfNode, PInfo.getTest(), CurrStates, FalseStates);
1184
1185    } else if (PInfo.isBinTest()) {
1186      CurrStates->setSource(PInfo.testSourceNode());
1187      FalseStates->setSource(PInfo.testSourceNode());
1188      splitVarStateForIfBinOp(PInfo, CurrStates, FalseStates);
1189
1190    } else {
1191      delete FalseStates;
1192      return false;
1193    }
1194
1195  } else if (const BinaryOperator *BinOp =
1196    dyn_cast_or_null<BinaryOperator>(CurrBlock->getTerminator().getStmt())) {
1197
1198    PInfo = Visitor.getInfo(BinOp->getLHS());
1199    if (!PInfo.isTest()) {
1200      if ((BinOp = dyn_cast_or_null<BinaryOperator>(BinOp->getLHS()))) {
1201        PInfo = Visitor.getInfo(BinOp->getRHS());
1202
1203        if (!PInfo.isTest()) {
1204          delete FalseStates;
1205          return false;
1206        }
1207
1208      } else {
1209        delete FalseStates;
1210        return false;
1211      }
1212    }
1213
1214    CurrStates->setSource(BinOp);
1215    FalseStates->setSource(BinOp);
1216
1217    const VarTestResult &Test = PInfo.getTest();
1218    ConsumedState VarState = CurrStates->getState(Test.Var);
1219
1220    if (BinOp->getOpcode() == BO_LAnd) {
1221      if (VarState == CS_Unknown)
1222        CurrStates->setState(Test.Var, Test.TestsFor);
1223      else if (VarState == invertConsumedUnconsumed(Test.TestsFor))
1224        CurrStates->markUnreachable();
1225
1226    } else if (BinOp->getOpcode() == BO_LOr) {
1227      if (VarState == CS_Unknown)
1228        FalseStates->setState(Test.Var,
1229                              invertConsumedUnconsumed(Test.TestsFor));
1230      else if (VarState == Test.TestsFor)
1231        FalseStates->markUnreachable();
1232    }
1233
1234  } else {
1235    delete FalseStates;
1236    return false;
1237  }
1238
1239  CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin();
1240
1241  if (*SI)
1242    BlockInfo.addInfo(*SI, CurrStates);
1243  else
1244    delete CurrStates;
1245
1246  if (*++SI)
1247    BlockInfo.addInfo(*SI, FalseStates);
1248  else
1249    delete FalseStates;
1250
1251  CurrStates = NULL;
1252  return true;
1253}
1254
1255void ConsumedAnalyzer::run(AnalysisDeclContext &AC) {
1256  const FunctionDecl *D = dyn_cast_or_null<FunctionDecl>(AC.getDecl());
1257  if (!D)
1258    return;
1259
1260  CFG *CFGraph = AC.getCFG();
1261  if (!CFGraph)
1262    return;
1263
1264  determineExpectedReturnState(AC, D);
1265
1266  PostOrderCFGView *SortedGraph = AC.getAnalysis<PostOrderCFGView>();
1267  // AC.getCFG()->viewCFG(LangOptions());
1268
1269  BlockInfo = ConsumedBlockInfo(CFGraph->getNumBlockIDs(), SortedGraph);
1270
1271  CurrStates = new ConsumedStateMap();
1272  ConsumedStmtVisitor Visitor(AC, *this, CurrStates);
1273
1274  // Add all trackable parameters to the state map.
1275  for (FunctionDecl::param_const_iterator PI = D->param_begin(),
1276       PE = D->param_end(); PI != PE; ++PI) {
1277    Visitor.VisitParmVarDecl(*PI);
1278  }
1279
1280  // Visit all of the function's basic blocks.
1281  for (PostOrderCFGView::iterator I = SortedGraph->begin(),
1282       E = SortedGraph->end(); I != E; ++I) {
1283
1284    const CFGBlock *CurrBlock = *I;
1285
1286    if (CurrStates == NULL)
1287      CurrStates = BlockInfo.getInfo(CurrBlock);
1288
1289    if (!CurrStates) {
1290      continue;
1291
1292    } else if (!CurrStates->isReachable()) {
1293      delete CurrStates;
1294      CurrStates = NULL;
1295      continue;
1296    }
1297
1298    Visitor.reset(CurrStates);
1299
1300    // Visit all of the basic block's statements.
1301    for (CFGBlock::const_iterator BI = CurrBlock->begin(),
1302         BE = CurrBlock->end(); BI != BE; ++BI) {
1303
1304      switch (BI->getKind()) {
1305      case CFGElement::Statement:
1306        Visitor.Visit(BI->castAs<CFGStmt>().getStmt());
1307        break;
1308
1309      case CFGElement::TemporaryDtor: {
1310        const CFGTemporaryDtor DTor = BI->castAs<CFGTemporaryDtor>();
1311        const CXXBindTemporaryExpr *BTE = DTor.getBindTemporaryExpr();
1312        PropagationInfo PInfo = Visitor.getInfo(BTE);
1313
1314        if (PInfo.isValid())
1315          Visitor.checkCallability(PInfo,
1316                                   DTor.getDestructorDecl(AC.getASTContext()),
1317                                   BTE->getExprLoc());
1318        break;
1319      }
1320
1321      case CFGElement::AutomaticObjectDtor: {
1322        const CFGAutomaticObjDtor DTor = BI->castAs<CFGAutomaticObjDtor>();
1323
1324        const VarDecl *Var = DTor.getVarDecl();
1325        ConsumedState VarState = CurrStates->getState(Var);
1326
1327        if (VarState != CS_None) {
1328          PropagationInfo PInfo(Var);
1329
1330          Visitor.checkCallability(PInfo,
1331                                   DTor.getDestructorDecl(AC.getASTContext()),
1332                                   getLastStmtLoc(CurrBlock));
1333
1334          CurrStates->remove(Var);
1335        }
1336        break;
1337      }
1338
1339      default:
1340        break;
1341      }
1342    }
1343
1344    // TODO: Handle other forms of branching with precision, including while-
1345    //       and for-loops. (Deferred)
1346    if (!splitState(CurrBlock, Visitor)) {
1347      CurrStates->setSource(NULL);
1348
1349      if (CurrBlock->succ_size() > 1 ||
1350          (CurrBlock->succ_size() == 1 &&
1351           (*CurrBlock->succ_begin())->pred_size() > 1)) {
1352
1353        bool OwnershipTaken = false;
1354
1355        for (CFGBlock::const_succ_iterator SI = CurrBlock->succ_begin(),
1356             SE = CurrBlock->succ_end(); SI != SE; ++SI) {
1357
1358          if (*SI == NULL) continue;
1359
1360          if (BlockInfo.isBackEdge(CurrBlock, *SI)) {
1361            BlockInfo.borrowInfo(*SI)->intersectAtLoopHead(*SI, CurrBlock,
1362                                                           CurrStates,
1363                                                           WarningsHandler);
1364
1365            if (BlockInfo.allBackEdgesVisited(*SI, CurrBlock))
1366              BlockInfo.discardInfo(*SI);
1367          } else {
1368            BlockInfo.addInfo(*SI, CurrStates, OwnershipTaken);
1369          }
1370        }
1371
1372        if (!OwnershipTaken)
1373          delete CurrStates;
1374
1375        CurrStates = NULL;
1376      }
1377    }
1378  } // End of block iterator.
1379
1380  // Delete the last existing state map.
1381  delete CurrStates;
1382
1383  WarningsHandler.emitDiagnostics();
1384}
1385}} // end namespace clang::consumed
1386