BugReporter.cpp revision e172e8b9e7fc67d7d03589af7e92fe777afcf33a 
1// BugReporter.cpp - Generate PathDiagnostics for Bugs ------------*- 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//  This file defines BugReporter, a utility class for generating
11//  PathDiagnostics.
12//
13//===----------------------------------------------------------------------===//
14
15#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
16#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
17#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
18#include "clang/AST/ASTContext.h"
19#include "clang/Analysis/CFG.h"
20#include "clang/AST/Expr.h"
21#include "clang/AST/ParentMap.h"
22#include "clang/AST/StmtObjC.h"
23#include "clang/Basic/SourceManager.h"
24#include "clang/Analysis/ProgramPoint.h"
25#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
26#include "llvm/Support/raw_ostream.h"
27#include "llvm/ADT/DenseMap.h"
28#include "llvm/ADT/STLExtras.h"
29#include "llvm/ADT/OwningPtr.h"
30#include <queue>
31
32using namespace clang;
33using namespace ento;
34
35BugReporterVisitor::~BugReporterVisitor() {}
36BugReporterContext::~BugReporterContext() {
37  for (visitor_iterator I = visitor_begin(), E = visitor_end(); I != E; ++I)
38    if ((*I)->isOwnedByReporterContext()) delete *I;
39}
40
41void BugReporterContext::addVisitor(BugReporterVisitor* visitor) {
42  if (!visitor)
43    return;
44
45  llvm::FoldingSetNodeID ID;
46  visitor->Profile(ID);
47  void *InsertPos;
48
49  if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) {
50    delete visitor;
51    return;
52  }
53
54  CallbacksSet.InsertNode(visitor, InsertPos);
55  Callbacks = F.add(visitor, Callbacks);
56}
57
58//===----------------------------------------------------------------------===//
59// Helper routines for walking the ExplodedGraph and fetching statements.
60//===----------------------------------------------------------------------===//
61
62static inline const Stmt *GetStmt(const ProgramPoint &P) {
63  if (const StmtPoint* SP = dyn_cast<StmtPoint>(&P))
64    return SP->getStmt();
65  else if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P))
66    return BE->getSrc()->getTerminator();
67
68  return 0;
69}
70
71static inline const ExplodedNode*
72GetPredecessorNode(const ExplodedNode *N) {
73  return N->pred_empty() ? NULL : *(N->pred_begin());
74}
75
76static inline const ExplodedNode*
77GetSuccessorNode(const ExplodedNode *N) {
78  return N->succ_empty() ? NULL : *(N->succ_begin());
79}
80
81static const Stmt *GetPreviousStmt(const ExplodedNode *N) {
82  for (N = GetPredecessorNode(N); N; N = GetPredecessorNode(N))
83    if (const Stmt *S = GetStmt(N->getLocation()))
84      return S;
85
86  return 0;
87}
88
89static const Stmt *GetNextStmt(const ExplodedNode *N) {
90  for (N = GetSuccessorNode(N); N; N = GetSuccessorNode(N))
91    if (const Stmt *S = GetStmt(N->getLocation())) {
92      // Check if the statement is '?' or '&&'/'||'.  These are "merges",
93      // not actual statement points.
94      switch (S->getStmtClass()) {
95        case Stmt::ChooseExprClass:
96        case Stmt::BinaryConditionalOperatorClass: continue;
97        case Stmt::ConditionalOperatorClass: continue;
98        case Stmt::BinaryOperatorClass: {
99          BinaryOperatorKind Op = cast<BinaryOperator>(S)->getOpcode();
100          if (Op == BO_LAnd || Op == BO_LOr)
101            continue;
102          break;
103        }
104        default:
105          break;
106      }
107
108      // Some expressions don't have locations.
109      if (S->getLocStart().isInvalid())
110        continue;
111
112      return S;
113    }
114
115  return 0;
116}
117
118static inline const Stmt*
119GetCurrentOrPreviousStmt(const ExplodedNode *N) {
120  if (const Stmt *S = GetStmt(N->getLocation()))
121    return S;
122
123  return GetPreviousStmt(N);
124}
125
126static inline const Stmt*
127GetCurrentOrNextStmt(const ExplodedNode *N) {
128  if (const Stmt *S = GetStmt(N->getLocation()))
129    return S;
130
131  return GetNextStmt(N);
132}
133
134//===----------------------------------------------------------------------===//
135// PathDiagnosticBuilder and its associated routines and helper objects.
136//===----------------------------------------------------------------------===//
137
138typedef llvm::DenseMap<const ExplodedNode*,
139const ExplodedNode*> NodeBackMap;
140
141namespace {
142class NodeMapClosure : public BugReport::NodeResolver {
143  NodeBackMap& M;
144public:
145  NodeMapClosure(NodeBackMap *m) : M(*m) {}
146  ~NodeMapClosure() {}
147
148  const ExplodedNode *getOriginalNode(const ExplodedNode *N) {
149    NodeBackMap::iterator I = M.find(N);
150    return I == M.end() ? 0 : I->second;
151  }
152};
153
154class PathDiagnosticBuilder : public BugReporterContext {
155  BugReport *R;
156  PathDiagnosticClient *PDC;
157  llvm::OwningPtr<ParentMap> PM;
158  NodeMapClosure NMC;
159public:
160  PathDiagnosticBuilder(GRBugReporter &br,
161                        BugReport *r, NodeBackMap *Backmap,
162                        PathDiagnosticClient *pdc)
163    : BugReporterContext(br),
164      R(r), PDC(pdc), NMC(Backmap) {
165    addVisitor(R);
166  }
167
168  PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N);
169
170  PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os,
171                                            const ExplodedNode *N);
172
173  Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); }
174
175  ParentMap& getParentMap() { return R->getErrorNode()->getParentMap(); }
176
177  const Stmt *getParent(const Stmt *S) {
178    return getParentMap().getParent(S);
179  }
180
181  virtual NodeMapClosure& getNodeResolver() { return NMC; }
182
183  PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S);
184
185  PathDiagnosticClient::PathGenerationScheme getGenerationScheme() const {
186    return PDC ? PDC->getGenerationScheme() : PathDiagnosticClient::Extensive;
187  }
188
189  bool supportsLogicalOpControlFlow() const {
190    return PDC ? PDC->supportsLogicalOpControlFlow() : true;
191  }
192};
193} // end anonymous namespace
194
195PathDiagnosticLocation
196PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) {
197  if (const Stmt *S = GetNextStmt(N))
198    return PathDiagnosticLocation(S, getSourceManager());
199
200  return FullSourceLoc(N->getLocationContext()->getDecl()->getBodyRBrace(),
201                       getSourceManager());
202}
203
204PathDiagnosticLocation
205PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os,
206                                          const ExplodedNode *N) {
207
208  // Slow, but probably doesn't matter.
209  if (os.str().empty())
210    os << ' ';
211
212  const PathDiagnosticLocation &Loc = ExecutionContinues(N);
213
214  if (Loc.asStmt())
215    os << "Execution continues on line "
216       << getSourceManager().getExpansionLineNumber(Loc.asLocation())
217       << '.';
218  else {
219    os << "Execution jumps to the end of the ";
220    const Decl *D = N->getLocationContext()->getDecl();
221    if (isa<ObjCMethodDecl>(D))
222      os << "method";
223    else if (isa<FunctionDecl>(D))
224      os << "function";
225    else {
226      assert(isa<BlockDecl>(D));
227      os << "anonymous block";
228    }
229    os << '.';
230  }
231
232  return Loc;
233}
234
235static bool IsNested(const Stmt *S, ParentMap &PM) {
236  if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S)))
237    return true;
238
239  const Stmt *Parent = PM.getParentIgnoreParens(S);
240
241  if (Parent)
242    switch (Parent->getStmtClass()) {
243      case Stmt::ForStmtClass:
244      case Stmt::DoStmtClass:
245      case Stmt::WhileStmtClass:
246        return true;
247      default:
248        break;
249    }
250
251  return false;
252}
253
254PathDiagnosticLocation
255PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) {
256  assert(S && "Null Stmt *passed to getEnclosingStmtLocation");
257  ParentMap &P = getParentMap();
258  SourceManager &SMgr = getSourceManager();
259
260  while (IsNested(S, P)) {
261    const Stmt *Parent = P.getParentIgnoreParens(S);
262
263    if (!Parent)
264      break;
265
266    switch (Parent->getStmtClass()) {
267      case Stmt::BinaryOperatorClass: {
268        const BinaryOperator *B = cast<BinaryOperator>(Parent);
269        if (B->isLogicalOp())
270          return PathDiagnosticLocation(S, SMgr);
271        break;
272      }
273      case Stmt::CompoundStmtClass:
274      case Stmt::StmtExprClass:
275        return PathDiagnosticLocation(S, SMgr);
276      case Stmt::ChooseExprClass:
277        // Similar to '?' if we are referring to condition, just have the edge
278        // point to the entire choose expression.
279        if (cast<ChooseExpr>(Parent)->getCond() == S)
280          return PathDiagnosticLocation(Parent, SMgr);
281        else
282          return PathDiagnosticLocation(S, SMgr);
283      case Stmt::BinaryConditionalOperatorClass:
284      case Stmt::ConditionalOperatorClass:
285        // For '?', if we are referring to condition, just have the edge point
286        // to the entire '?' expression.
287        if (cast<AbstractConditionalOperator>(Parent)->getCond() == S)
288          return PathDiagnosticLocation(Parent, SMgr);
289        else
290          return PathDiagnosticLocation(S, SMgr);
291      case Stmt::DoStmtClass:
292          return PathDiagnosticLocation(S, SMgr);
293      case Stmt::ForStmtClass:
294        if (cast<ForStmt>(Parent)->getBody() == S)
295          return PathDiagnosticLocation(S, SMgr);
296        break;
297      case Stmt::IfStmtClass:
298        if (cast<IfStmt>(Parent)->getCond() != S)
299          return PathDiagnosticLocation(S, SMgr);
300        break;
301      case Stmt::ObjCForCollectionStmtClass:
302        if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S)
303          return PathDiagnosticLocation(S, SMgr);
304        break;
305      case Stmt::WhileStmtClass:
306        if (cast<WhileStmt>(Parent)->getCond() != S)
307          return PathDiagnosticLocation(S, SMgr);
308        break;
309      default:
310        break;
311    }
312
313    S = Parent;
314  }
315
316  assert(S && "Cannot have null Stmt for PathDiagnosticLocation");
317
318  // Special case: DeclStmts can appear in for statement declarations, in which
319  //  case the ForStmt is the context.
320  if (isa<DeclStmt>(S)) {
321    if (const Stmt *Parent = P.getParent(S)) {
322      switch (Parent->getStmtClass()) {
323        case Stmt::ForStmtClass:
324        case Stmt::ObjCForCollectionStmtClass:
325          return PathDiagnosticLocation(Parent, SMgr);
326        default:
327          break;
328      }
329    }
330  }
331  else if (isa<BinaryOperator>(S)) {
332    // Special case: the binary operator represents the initialization
333    // code in a for statement (this can happen when the variable being
334    // initialized is an old variable.
335    if (const ForStmt *FS =
336          dyn_cast_or_null<ForStmt>(P.getParentIgnoreParens(S))) {
337      if (FS->getInit() == S)
338        return PathDiagnosticLocation(FS, SMgr);
339    }
340  }
341
342  return PathDiagnosticLocation(S, SMgr);
343}
344
345//===----------------------------------------------------------------------===//
346// ScanNotableSymbols: closure-like callback for scanning Store bindings.
347//===----------------------------------------------------------------------===//
348
349static const VarDecl* GetMostRecentVarDeclBinding(const ExplodedNode *N,
350                                                  ProgramStateManager& VMgr,
351                                                  SVal X) {
352
353  for ( ; N ; N = N->pred_empty() ? 0 : *N->pred_begin()) {
354
355    ProgramPoint P = N->getLocation();
356
357    if (!isa<PostStmt>(P))
358      continue;
359
360    const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(cast<PostStmt>(P).getStmt());
361
362    if (!DR)
363      continue;
364
365    SVal Y = N->getState()->getSVal(DR);
366
367    if (X != Y)
368      continue;
369
370    const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl());
371
372    if (!VD)
373      continue;
374
375    return VD;
376  }
377
378  return 0;
379}
380
381namespace {
382class NotableSymbolHandler
383: public StoreManager::BindingsHandler {
384
385  SymbolRef Sym;
386  const ProgramState *PrevSt;
387  const Stmt *S;
388  ProgramStateManager& VMgr;
389  const ExplodedNode *Pred;
390  PathDiagnostic& PD;
391  BugReporter& BR;
392
393public:
394
395  NotableSymbolHandler(SymbolRef sym,
396                       const ProgramState *prevst,
397                       const Stmt *s,
398                       ProgramStateManager& vmgr,
399                       const ExplodedNode *pred,
400                       PathDiagnostic& pd,
401                       BugReporter& br)
402  : Sym(sym),
403    PrevSt(prevst),
404    S(s),
405    VMgr(vmgr),
406    Pred(pred),
407    PD(pd),
408    BR(br) {}
409
410  bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
411                     SVal V) {
412
413    SymbolRef ScanSym = V.getAsSymbol();
414
415    if (ScanSym != Sym)
416      return true;
417
418    // Check if the previous state has this binding.
419    SVal X = PrevSt->getSVal(loc::MemRegionVal(R));
420
421    if (X == V) // Same binding?
422      return true;
423
424    // Different binding.  Only handle assignments for now.  We don't pull
425    // this check out of the loop because we will eventually handle other
426    // cases.
427
428    VarDecl *VD = 0;
429
430    if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
431      if (!B->isAssignmentOp())
432        return true;
433
434      // What variable did we assign to?
435      DeclRefExpr *DR = dyn_cast<DeclRefExpr>(B->getLHS()->IgnoreParenCasts());
436
437      if (!DR)
438        return true;
439
440      VD = dyn_cast<VarDecl>(DR->getDecl());
441    }
442    else if (const DeclStmt *DS = dyn_cast<DeclStmt>(S)) {
443      // FIXME: Eventually CFGs won't have DeclStmts.  Right now we
444      //  assume that each DeclStmt has a single Decl.  This invariant
445      //  holds by construction in the CFG.
446      VD = dyn_cast<VarDecl>(*DS->decl_begin());
447    }
448
449    if (!VD)
450      return true;
451
452    // What is the most recently referenced variable with this binding?
453    const VarDecl *MostRecent = GetMostRecentVarDeclBinding(Pred, VMgr, V);
454
455    if (!MostRecent)
456      return true;
457
458    // Create the diagnostic.
459    FullSourceLoc L(S->getLocStart(), BR.getSourceManager());
460
461    if (Loc::isLocType(VD->getType())) {
462      std::string msg = "'" + std::string(VD->getNameAsString()) +
463      "' now aliases '" + MostRecent->getNameAsString() + "'";
464
465      PD.push_front(new PathDiagnosticEventPiece(L, msg));
466    }
467
468    return true;
469  }
470};
471}
472
473static void HandleNotableSymbol(const ExplodedNode *N,
474                                const Stmt *S,
475                                SymbolRef Sym, BugReporter& BR,
476                                PathDiagnostic& PD) {
477
478  const ExplodedNode *Pred = N->pred_empty() ? 0 : *N->pred_begin();
479  const ProgramState *PrevSt = Pred ? Pred->getState() : 0;
480
481  if (!PrevSt)
482    return;
483
484  // Look at the region bindings of the current state that map to the
485  // specified symbol.  Are any of them not in the previous state?
486  ProgramStateManager& VMgr = cast<GRBugReporter>(BR).getStateManager();
487  NotableSymbolHandler H(Sym, PrevSt, S, VMgr, Pred, PD, BR);
488  cast<GRBugReporter>(BR).getStateManager().iterBindings(N->getState(), H);
489}
490
491namespace {
492class ScanNotableSymbols
493: public StoreManager::BindingsHandler {
494
495  llvm::SmallSet<SymbolRef, 10> AlreadyProcessed;
496  const ExplodedNode *N;
497  const Stmt *S;
498  GRBugReporter& BR;
499  PathDiagnostic& PD;
500
501public:
502  ScanNotableSymbols(const ExplodedNode *n, const Stmt *s,
503                     GRBugReporter& br, PathDiagnostic& pd)
504  : N(n), S(s), BR(br), PD(pd) {}
505
506  bool HandleBinding(StoreManager& SMgr, Store store,
507                     const MemRegion* R, SVal V) {
508
509    SymbolRef ScanSym = V.getAsSymbol();
510
511    if (!ScanSym)
512      return true;
513
514    if (!BR.isNotable(ScanSym))
515      return true;
516
517    if (AlreadyProcessed.count(ScanSym))
518      return true;
519
520    AlreadyProcessed.insert(ScanSym);
521
522    HandleNotableSymbol(N, S, ScanSym, BR, PD);
523    return true;
524  }
525};
526} // end anonymous namespace
527
528//===----------------------------------------------------------------------===//
529// "Minimal" path diagnostic generation algorithm.
530//===----------------------------------------------------------------------===//
531
532static void CompactPathDiagnostic(PathDiagnostic &PD, const SourceManager& SM);
533
534static void GenerateMinimalPathDiagnostic(PathDiagnostic& PD,
535                                          PathDiagnosticBuilder &PDB,
536                                          const ExplodedNode *N) {
537
538  SourceManager& SMgr = PDB.getSourceManager();
539  const ExplodedNode *NextNode = N->pred_empty()
540                                        ? NULL : *(N->pred_begin());
541  while (NextNode) {
542    N = NextNode;
543    NextNode = GetPredecessorNode(N);
544
545    ProgramPoint P = N->getLocation();
546
547    if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
548      const CFGBlock *Src = BE->getSrc();
549      const CFGBlock *Dst = BE->getDst();
550      const Stmt *T = Src->getTerminator();
551
552      if (!T)
553        continue;
554
555      FullSourceLoc Start(T->getLocStart(), SMgr);
556
557      switch (T->getStmtClass()) {
558        default:
559          break;
560
561        case Stmt::GotoStmtClass:
562        case Stmt::IndirectGotoStmtClass: {
563          const Stmt *S = GetNextStmt(N);
564
565          if (!S)
566            continue;
567
568          std::string sbuf;
569          llvm::raw_string_ostream os(sbuf);
570          const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S);
571
572          os << "Control jumps to line "
573          << End.asLocation().getExpansionLineNumber();
574          PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
575                                                           os.str()));
576          break;
577        }
578
579        case Stmt::SwitchStmtClass: {
580          // Figure out what case arm we took.
581          std::string sbuf;
582          llvm::raw_string_ostream os(sbuf);
583
584          if (const Stmt *S = Dst->getLabel()) {
585            PathDiagnosticLocation End(S, SMgr);
586
587            switch (S->getStmtClass()) {
588              default:
589                os << "No cases match in the switch statement. "
590                "Control jumps to line "
591                << End.asLocation().getExpansionLineNumber();
592                break;
593              case Stmt::DefaultStmtClass:
594                os << "Control jumps to the 'default' case at line "
595                << End.asLocation().getExpansionLineNumber();
596                break;
597
598              case Stmt::CaseStmtClass: {
599                os << "Control jumps to 'case ";
600                const CaseStmt *Case = cast<CaseStmt>(S);
601                const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
602
603                // Determine if it is an enum.
604                bool GetRawInt = true;
605
606                if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) {
607                  // FIXME: Maybe this should be an assertion.  Are there cases
608                  // were it is not an EnumConstantDecl?
609                  const EnumConstantDecl *D =
610                    dyn_cast<EnumConstantDecl>(DR->getDecl());
611
612                  if (D) {
613                    GetRawInt = false;
614                    os << D;
615                  }
616                }
617
618                if (GetRawInt)
619                  os << LHS->EvaluateAsInt(PDB.getASTContext());
620
621                os << ":'  at line "
622                << End.asLocation().getExpansionLineNumber();
623                break;
624              }
625            }
626            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
627                                                             os.str()));
628          }
629          else {
630            os << "'Default' branch taken. ";
631            const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N);
632            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
633                                                             os.str()));
634          }
635
636          break;
637        }
638
639        case Stmt::BreakStmtClass:
640        case Stmt::ContinueStmtClass: {
641          std::string sbuf;
642          llvm::raw_string_ostream os(sbuf);
643          PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
644          PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
645                                                           os.str()));
646          break;
647        }
648
649          // Determine control-flow for ternary '?'.
650        case Stmt::BinaryConditionalOperatorClass:
651        case Stmt::ConditionalOperatorClass: {
652          std::string sbuf;
653          llvm::raw_string_ostream os(sbuf);
654          os << "'?' condition is ";
655
656          if (*(Src->succ_begin()+1) == Dst)
657            os << "false";
658          else
659            os << "true";
660
661          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
662
663          if (const Stmt *S = End.asStmt())
664            End = PDB.getEnclosingStmtLocation(S);
665
666          PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
667                                                           os.str()));
668          break;
669        }
670
671          // Determine control-flow for short-circuited '&&' and '||'.
672        case Stmt::BinaryOperatorClass: {
673          if (!PDB.supportsLogicalOpControlFlow())
674            break;
675
676          const BinaryOperator *B = cast<BinaryOperator>(T);
677          std::string sbuf;
678          llvm::raw_string_ostream os(sbuf);
679          os << "Left side of '";
680
681          if (B->getOpcode() == BO_LAnd) {
682            os << "&&" << "' is ";
683
684            if (*(Src->succ_begin()+1) == Dst) {
685              os << "false";
686              PathDiagnosticLocation End(B->getLHS(), SMgr);
687              PathDiagnosticLocation Start(B->getOperatorLoc(), SMgr);
688              PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
689                                                               os.str()));
690            }
691            else {
692              os << "true";
693              PathDiagnosticLocation Start(B->getLHS(), SMgr);
694              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
695              PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
696                                                               os.str()));
697            }
698          }
699          else {
700            assert(B->getOpcode() == BO_LOr);
701            os << "||" << "' is ";
702
703            if (*(Src->succ_begin()+1) == Dst) {
704              os << "false";
705              PathDiagnosticLocation Start(B->getLHS(), SMgr);
706              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
707              PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
708                                                               os.str()));
709            }
710            else {
711              os << "true";
712              PathDiagnosticLocation End(B->getLHS(), SMgr);
713              PathDiagnosticLocation Start(B->getOperatorLoc(), SMgr);
714              PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
715                                                               os.str()));
716            }
717          }
718
719          break;
720        }
721
722        case Stmt::DoStmtClass:  {
723          if (*(Src->succ_begin()) == Dst) {
724            std::string sbuf;
725            llvm::raw_string_ostream os(sbuf);
726
727            os << "Loop condition is true. ";
728            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
729
730            if (const Stmt *S = End.asStmt())
731              End = PDB.getEnclosingStmtLocation(S);
732
733            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
734                                                             os.str()));
735          }
736          else {
737            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
738
739            if (const Stmt *S = End.asStmt())
740              End = PDB.getEnclosingStmtLocation(S);
741
742            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
743                              "Loop condition is false.  Exiting loop"));
744          }
745
746          break;
747        }
748
749        case Stmt::WhileStmtClass:
750        case Stmt::ForStmtClass: {
751          if (*(Src->succ_begin()+1) == Dst) {
752            std::string sbuf;
753            llvm::raw_string_ostream os(sbuf);
754
755            os << "Loop condition is false. ";
756            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
757            if (const Stmt *S = End.asStmt())
758              End = PDB.getEnclosingStmtLocation(S);
759
760            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
761                                                             os.str()));
762          }
763          else {
764            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
765            if (const Stmt *S = End.asStmt())
766              End = PDB.getEnclosingStmtLocation(S);
767
768            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
769                            "Loop condition is true.  Entering loop body"));
770          }
771
772          break;
773        }
774
775        case Stmt::IfStmtClass: {
776          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
777
778          if (const Stmt *S = End.asStmt())
779            End = PDB.getEnclosingStmtLocation(S);
780
781          if (*(Src->succ_begin()+1) == Dst)
782            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
783                                                        "Taking false branch"));
784          else
785            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
786                                                         "Taking true branch"));
787
788          break;
789        }
790      }
791    }
792
793    if (NextNode) {
794      for (BugReporterContext::visitor_iterator I = PDB.visitor_begin(),
795           E = PDB.visitor_end(); I!=E; ++I) {
796        if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB))
797          PD.push_front(p);
798      }
799    }
800
801    if (const PostStmt *PS = dyn_cast<PostStmt>(&P)) {
802      // Scan the region bindings, and see if a "notable" symbol has a new
803      // lval binding.
804      ScanNotableSymbols SNS(N, PS->getStmt(), PDB.getBugReporter(), PD);
805      PDB.getStateManager().iterBindings(N->getState(), SNS);
806    }
807  }
808
809  // After constructing the full PathDiagnostic, do a pass over it to compact
810  // PathDiagnosticPieces that occur within a macro.
811  CompactPathDiagnostic(PD, PDB.getSourceManager());
812}
813
814//===----------------------------------------------------------------------===//
815// "Extensive" PathDiagnostic generation.
816//===----------------------------------------------------------------------===//
817
818static bool IsControlFlowExpr(const Stmt *S) {
819  const Expr *E = dyn_cast<Expr>(S);
820
821  if (!E)
822    return false;
823
824  E = E->IgnoreParenCasts();
825
826  if (isa<AbstractConditionalOperator>(E))
827    return true;
828
829  if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E))
830    if (B->isLogicalOp())
831      return true;
832
833  return false;
834}
835
836namespace {
837class ContextLocation : public PathDiagnosticLocation {
838  bool IsDead;
839public:
840  ContextLocation(const PathDiagnosticLocation &L, bool isdead = false)
841    : PathDiagnosticLocation(L), IsDead(isdead) {}
842
843  void markDead() { IsDead = true; }
844  bool isDead() const { return IsDead; }
845};
846
847class EdgeBuilder {
848  std::vector<ContextLocation> CLocs;
849  typedef std::vector<ContextLocation>::iterator iterator;
850  PathDiagnostic &PD;
851  PathDiagnosticBuilder &PDB;
852  PathDiagnosticLocation PrevLoc;
853
854  bool IsConsumedExpr(const PathDiagnosticLocation &L);
855
856  bool containsLocation(const PathDiagnosticLocation &Container,
857                        const PathDiagnosticLocation &Containee);
858
859  PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L);
860
861  PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L,
862                                         bool firstCharOnly = false) {
863    if (const Stmt *S = L.asStmt()) {
864      const Stmt *Original = S;
865      while (1) {
866        // Adjust the location for some expressions that are best referenced
867        // by one of their subexpressions.
868        switch (S->getStmtClass()) {
869          default:
870            break;
871          case Stmt::ParenExprClass:
872          case Stmt::GenericSelectionExprClass:
873            S = cast<Expr>(S)->IgnoreParens();
874            firstCharOnly = true;
875            continue;
876          case Stmt::BinaryConditionalOperatorClass:
877          case Stmt::ConditionalOperatorClass:
878            S = cast<AbstractConditionalOperator>(S)->getCond();
879            firstCharOnly = true;
880            continue;
881          case Stmt::ChooseExprClass:
882            S = cast<ChooseExpr>(S)->getCond();
883            firstCharOnly = true;
884            continue;
885          case Stmt::BinaryOperatorClass:
886            S = cast<BinaryOperator>(S)->getLHS();
887            firstCharOnly = true;
888            continue;
889        }
890
891        break;
892      }
893
894      if (S != Original)
895        L = PathDiagnosticLocation(S, L.getManager());
896    }
897
898    if (firstCharOnly)
899      L = PathDiagnosticLocation(L.asLocation());
900
901    return L;
902  }
903
904  void popLocation() {
905    if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) {
906      // For contexts, we only one the first character as the range.
907      rawAddEdge(cleanUpLocation(CLocs.back(), true));
908    }
909    CLocs.pop_back();
910  }
911
912public:
913  EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb)
914    : PD(pd), PDB(pdb) {
915
916      // If the PathDiagnostic already has pieces, add the enclosing statement
917      // of the first piece as a context as well.
918      if (!PD.empty()) {
919        PrevLoc = PD.begin()->getLocation();
920
921        if (const Stmt *S = PrevLoc.asStmt())
922          addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
923      }
924  }
925
926  ~EdgeBuilder() {
927    while (!CLocs.empty()) popLocation();
928
929    // Finally, add an initial edge from the start location of the first
930    // statement (if it doesn't already exist).
931    // FIXME: Should handle CXXTryStmt if analyser starts supporting C++.
932    if (const CompoundStmt *CS =
933          dyn_cast_or_null<CompoundStmt>(PDB.getCodeDecl().getBody()))
934      if (!CS->body_empty()) {
935        SourceLocation Loc = (*CS->body_begin())->getLocStart();
936        rawAddEdge(PathDiagnosticLocation(Loc, PDB.getSourceManager()));
937      }
938
939  }
940
941  void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false);
942
943  void rawAddEdge(PathDiagnosticLocation NewLoc);
944
945  void addContext(const Stmt *S);
946  void addExtendedContext(const Stmt *S);
947};
948} // end anonymous namespace
949
950
951PathDiagnosticLocation
952EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) {
953  if (const Stmt *S = L.asStmt()) {
954    if (IsControlFlowExpr(S))
955      return L;
956
957    return PDB.getEnclosingStmtLocation(S);
958  }
959
960  return L;
961}
962
963bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container,
964                                   const PathDiagnosticLocation &Containee) {
965
966  if (Container == Containee)
967    return true;
968
969  if (Container.asDecl())
970    return true;
971
972  if (const Stmt *S = Containee.asStmt())
973    if (const Stmt *ContainerS = Container.asStmt()) {
974      while (S) {
975        if (S == ContainerS)
976          return true;
977        S = PDB.getParent(S);
978      }
979      return false;
980    }
981
982  // Less accurate: compare using source ranges.
983  SourceRange ContainerR = Container.asRange();
984  SourceRange ContaineeR = Containee.asRange();
985
986  SourceManager &SM = PDB.getSourceManager();
987  SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin());
988  SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd());
989  SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin());
990  SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd());
991
992  unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg);
993  unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd);
994  unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg);
995  unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd);
996
997  assert(ContainerBegLine <= ContainerEndLine);
998  assert(ContaineeBegLine <= ContaineeEndLine);
999
1000  return (ContainerBegLine <= ContaineeBegLine &&
1001          ContainerEndLine >= ContaineeEndLine &&
1002          (ContainerBegLine != ContaineeBegLine ||
1003           SM.getExpansionColumnNumber(ContainerRBeg) <=
1004           SM.getExpansionColumnNumber(ContaineeRBeg)) &&
1005          (ContainerEndLine != ContaineeEndLine ||
1006           SM.getExpansionColumnNumber(ContainerREnd) >=
1007           SM.getExpansionColumnNumber(ContainerREnd)));
1008}
1009
1010void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) {
1011  if (!PrevLoc.isValid()) {
1012    PrevLoc = NewLoc;
1013    return;
1014  }
1015
1016  const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc);
1017  const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc);
1018
1019  if (NewLocClean.asLocation() == PrevLocClean.asLocation())
1020    return;
1021
1022  // FIXME: Ignore intra-macro edges for now.
1023  if (NewLocClean.asLocation().getExpansionLoc() ==
1024      PrevLocClean.asLocation().getExpansionLoc())
1025    return;
1026
1027  PD.push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean));
1028  PrevLoc = NewLoc;
1029}
1030
1031void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd) {
1032
1033  if (!alwaysAdd && NewLoc.asLocation().isMacroID())
1034    return;
1035
1036  const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc);
1037
1038  while (!CLocs.empty()) {
1039    ContextLocation &TopContextLoc = CLocs.back();
1040
1041    // Is the top location context the same as the one for the new location?
1042    if (TopContextLoc == CLoc) {
1043      if (alwaysAdd) {
1044        if (IsConsumedExpr(TopContextLoc) &&
1045            !IsControlFlowExpr(TopContextLoc.asStmt()))
1046            TopContextLoc.markDead();
1047
1048        rawAddEdge(NewLoc);
1049      }
1050
1051      return;
1052    }
1053
1054    if (containsLocation(TopContextLoc, CLoc)) {
1055      if (alwaysAdd) {
1056        rawAddEdge(NewLoc);
1057
1058        if (IsConsumedExpr(CLoc) && !IsControlFlowExpr(CLoc.asStmt())) {
1059          CLocs.push_back(ContextLocation(CLoc, true));
1060          return;
1061        }
1062      }
1063
1064      CLocs.push_back(CLoc);
1065      return;
1066    }
1067
1068    // Context does not contain the location.  Flush it.
1069    popLocation();
1070  }
1071
1072  // If we reach here, there is no enclosing context.  Just add the edge.
1073  rawAddEdge(NewLoc);
1074}
1075
1076bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) {
1077  if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt()))
1078    return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X);
1079
1080  return false;
1081}
1082
1083void EdgeBuilder::addExtendedContext(const Stmt *S) {
1084  if (!S)
1085    return;
1086
1087  const Stmt *Parent = PDB.getParent(S);
1088  while (Parent) {
1089    if (isa<CompoundStmt>(Parent))
1090      Parent = PDB.getParent(Parent);
1091    else
1092      break;
1093  }
1094
1095  if (Parent) {
1096    switch (Parent->getStmtClass()) {
1097      case Stmt::DoStmtClass:
1098      case Stmt::ObjCAtSynchronizedStmtClass:
1099        addContext(Parent);
1100      default:
1101        break;
1102    }
1103  }
1104
1105  addContext(S);
1106}
1107
1108void EdgeBuilder::addContext(const Stmt *S) {
1109  if (!S)
1110    return;
1111
1112  PathDiagnosticLocation L(S, PDB.getSourceManager());
1113
1114  while (!CLocs.empty()) {
1115    const PathDiagnosticLocation &TopContextLoc = CLocs.back();
1116
1117    // Is the top location context the same as the one for the new location?
1118    if (TopContextLoc == L)
1119      return;
1120
1121    if (containsLocation(TopContextLoc, L)) {
1122      CLocs.push_back(L);
1123      return;
1124    }
1125
1126    // Context does not contain the location.  Flush it.
1127    popLocation();
1128  }
1129
1130  CLocs.push_back(L);
1131}
1132
1133static void GenerateExtensivePathDiagnostic(PathDiagnostic& PD,
1134                                            PathDiagnosticBuilder &PDB,
1135                                            const ExplodedNode *N) {
1136  EdgeBuilder EB(PD, PDB);
1137
1138  const ExplodedNode *NextNode = N->pred_empty() ? NULL : *(N->pred_begin());
1139  while (NextNode) {
1140    N = NextNode;
1141    NextNode = GetPredecessorNode(N);
1142    ProgramPoint P = N->getLocation();
1143
1144    do {
1145      // Block edges.
1146      if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
1147        const CFGBlock &Blk = *BE->getSrc();
1148        const Stmt *Term = Blk.getTerminator();
1149
1150        // Are we jumping to the head of a loop?  Add a special diagnostic.
1151        if (const Stmt *Loop = BE->getDst()->getLoopTarget()) {
1152          PathDiagnosticLocation L(Loop, PDB.getSourceManager());
1153          const CompoundStmt *CS = NULL;
1154
1155          if (!Term) {
1156            if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
1157              CS = dyn_cast<CompoundStmt>(FS->getBody());
1158            else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
1159              CS = dyn_cast<CompoundStmt>(WS->getBody());
1160          }
1161
1162          PathDiagnosticEventPiece *p =
1163            new PathDiagnosticEventPiece(L,
1164                                        "Looping back to the head of the loop");
1165
1166          EB.addEdge(p->getLocation(), true);
1167          PD.push_front(p);
1168
1169          if (CS) {
1170            PathDiagnosticLocation BL(CS->getRBracLoc(),
1171                                      PDB.getSourceManager());
1172            BL = PathDiagnosticLocation(BL.asLocation());
1173            EB.addEdge(BL);
1174          }
1175        }
1176
1177        if (Term)
1178          EB.addContext(Term);
1179
1180        break;
1181      }
1182
1183      if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
1184        if (const CFGStmt *S = BE->getFirstElement().getAs<CFGStmt>()) {
1185          const Stmt *stmt = S->getStmt();
1186          if (IsControlFlowExpr(stmt)) {
1187            // Add the proper context for '&&', '||', and '?'.
1188            EB.addContext(stmt);
1189          }
1190          else
1191            EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt());
1192        }
1193
1194        break;
1195      }
1196    } while (0);
1197
1198    if (!NextNode)
1199      continue;
1200
1201    for (BugReporterContext::visitor_iterator I = PDB.visitor_begin(),
1202         E = PDB.visitor_end(); I!=E; ++I) {
1203      if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB)) {
1204        const PathDiagnosticLocation &Loc = p->getLocation();
1205        EB.addEdge(Loc, true);
1206        PD.push_front(p);
1207        if (const Stmt *S = Loc.asStmt())
1208          EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
1209      }
1210    }
1211  }
1212}
1213
1214//===----------------------------------------------------------------------===//
1215// Methods for BugType and subclasses.
1216//===----------------------------------------------------------------------===//
1217BugType::~BugType() { }
1218
1219void BugType::FlushReports(BugReporter &BR) {}
1220
1221//===----------------------------------------------------------------------===//
1222// Methods for BugReport and subclasses.
1223//===----------------------------------------------------------------------===//
1224
1225BugReport::~BugReport() {}
1226
1227void BugReport::Profile(llvm::FoldingSetNodeID& hash) const {
1228  hash.AddPointer(&BT);
1229  hash.AddInteger(getLocation().getRawEncoding());
1230  hash.AddString(Description);
1231
1232  for (SmallVectorImpl<SourceRange>::const_iterator I =
1233      Ranges.begin(), E = Ranges.end(); I != E; ++I) {
1234    const SourceRange range = *I;
1235    if (!range.isValid())
1236      continue;
1237    hash.AddInteger(range.getBegin().getRawEncoding());
1238    hash.AddInteger(range.getEnd().getRawEncoding());
1239  }
1240}
1241
1242const Stmt *BugReport::getStmt() const {
1243  if (!ErrorNode)
1244    return 0;
1245
1246  ProgramPoint ProgP = ErrorNode->getLocation();
1247  const Stmt *S = NULL;
1248
1249  if (BlockEntrance *BE = dyn_cast<BlockEntrance>(&ProgP)) {
1250    CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit();
1251    if (BE->getBlock() == &Exit)
1252      S = GetPreviousStmt(ErrorNode);
1253  }
1254  if (!S)
1255    S = GetStmt(ProgP);
1256
1257  return S;
1258}
1259
1260PathDiagnosticPiece*
1261BugReport::getEndPath(BugReporterContext &BRC,
1262                      const ExplodedNode *EndPathNode) {
1263
1264  const ProgramPoint &PP = EndPathNode->getLocation();
1265  PathDiagnosticLocation L;
1266
1267  if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&PP)) {
1268    const CFGBlock *block = BE->getBlock();
1269    if (block->getBlockID() == 0) {
1270      L = PathDiagnosticLocation(
1271          EndPathNode->getLocationContext()->getDecl()->getBodyRBrace(),
1272          BRC.getSourceManager());
1273    }
1274  }
1275
1276  if (!L.isValid()) {
1277    const Stmt *S = getStmt();
1278
1279    if (!S)
1280      return NULL;
1281
1282    L = PathDiagnosticLocation(S, BRC.getSourceManager());
1283  }
1284
1285  BugReport::ranges_iterator Beg, End;
1286  llvm::tie(Beg, End) = getRanges();
1287
1288  // Only add the statement itself as a range if we didn't specify any
1289  // special ranges for this report.
1290  PathDiagnosticPiece *P = new PathDiagnosticEventPiece(L, getDescription(),
1291                                                        Beg == End);
1292
1293  for (; Beg != End; ++Beg)
1294    P->addRange(*Beg);
1295
1296  return P;
1297}
1298
1299std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator>
1300BugReport::getRanges() {
1301    // If no custom ranges, add the range of the statement corresponding to
1302    // the error node.
1303    if (Ranges.empty()) {
1304      if (const Expr *E = dyn_cast_or_null<Expr>(getStmt()))
1305        addRange(E->getSourceRange());
1306      else
1307        return std::make_pair(ranges_iterator(), ranges_iterator());
1308    }
1309
1310    return std::make_pair(Ranges.begin(), Ranges.end());
1311}
1312
1313SourceLocation BugReport::getLocation() const {
1314  if (ErrorNode)
1315    if (const Stmt *S = GetCurrentOrPreviousStmt(ErrorNode)) {
1316      // For member expressions, return the location of the '.' or '->'.
1317      if (const MemberExpr *ME = dyn_cast<MemberExpr>(S))
1318        return ME->getMemberLoc();
1319      // For binary operators, return the location of the operator.
1320      if (const BinaryOperator *B = dyn_cast<BinaryOperator>(S))
1321        return B->getOperatorLoc();
1322
1323      return S->getLocStart();
1324    }
1325
1326  return FullSourceLoc();
1327}
1328
1329PathDiagnosticPiece *BugReport::VisitNode(const ExplodedNode *N,
1330                                          const ExplodedNode *PrevN,
1331                                          BugReporterContext &BRC) {
1332  return NULL;
1333}
1334
1335//===----------------------------------------------------------------------===//
1336// Methods for BugReporter and subclasses.
1337//===----------------------------------------------------------------------===//
1338
1339BugReportEquivClass::~BugReportEquivClass() {
1340  for (iterator I=begin(), E=end(); I!=E; ++I) delete *I;
1341}
1342
1343GRBugReporter::~GRBugReporter() { }
1344BugReporterData::~BugReporterData() {}
1345
1346ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); }
1347
1348ProgramStateManager&
1349GRBugReporter::getStateManager() { return Eng.getStateManager(); }
1350
1351BugReporter::~BugReporter() { FlushReports(); }
1352
1353void BugReporter::FlushReports() {
1354  if (BugTypes.isEmpty())
1355    return;
1356
1357  // First flush the warnings for each BugType.  This may end up creating new
1358  // warnings and new BugTypes.
1359  // FIXME: Only NSErrorChecker needs BugType's FlushReports.
1360  // Turn NSErrorChecker into a proper checker and remove this.
1361  SmallVector<const BugType*, 16> bugTypes;
1362  for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I)
1363    bugTypes.push_back(*I);
1364  for (SmallVector<const BugType*, 16>::iterator
1365         I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I)
1366    const_cast<BugType*>(*I)->FlushReports(*this);
1367
1368  typedef llvm::FoldingSet<BugReportEquivClass> SetTy;
1369  for (SetTy::iterator EI=EQClasses.begin(), EE=EQClasses.end(); EI!=EE;++EI){
1370    BugReportEquivClass& EQ = *EI;
1371    FlushReport(EQ);
1372  }
1373
1374  // BugReporter owns and deletes only BugTypes created implicitly through
1375  // EmitBasicReport.
1376  // FIXME: There are leaks from checkers that assume that the BugTypes they
1377  // create will be destroyed by the BugReporter.
1378  for (llvm::StringMap<BugType*>::iterator
1379         I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I)
1380    delete I->second;
1381
1382  // Remove all references to the BugType objects.
1383  BugTypes = F.getEmptySet();
1384}
1385
1386//===----------------------------------------------------------------------===//
1387// PathDiagnostics generation.
1388//===----------------------------------------------------------------------===//
1389
1390static std::pair<std::pair<ExplodedGraph*, NodeBackMap*>,
1391                 std::pair<ExplodedNode*, unsigned> >
1392MakeReportGraph(const ExplodedGraph* G,
1393                SmallVectorImpl<const ExplodedNode*> &nodes) {
1394
1395  // Create the trimmed graph.  It will contain the shortest paths from the
1396  // error nodes to the root.  In the new graph we should only have one
1397  // error node unless there are two or more error nodes with the same minimum
1398  // path length.
1399  ExplodedGraph* GTrim;
1400  InterExplodedGraphMap* NMap;
1401
1402  llvm::DenseMap<const void*, const void*> InverseMap;
1403  llvm::tie(GTrim, NMap) = G->Trim(nodes.data(), nodes.data() + nodes.size(),
1404                                   &InverseMap);
1405
1406  // Create owning pointers for GTrim and NMap just to ensure that they are
1407  // released when this function exists.
1408  llvm::OwningPtr<ExplodedGraph> AutoReleaseGTrim(GTrim);
1409  llvm::OwningPtr<InterExplodedGraphMap> AutoReleaseNMap(NMap);
1410
1411  // Find the (first) error node in the trimmed graph.  We just need to consult
1412  // the node map (NMap) which maps from nodes in the original graph to nodes
1413  // in the new graph.
1414
1415  std::queue<const ExplodedNode*> WS;
1416  typedef llvm::DenseMap<const ExplodedNode*, unsigned> IndexMapTy;
1417  IndexMapTy IndexMap;
1418
1419  for (unsigned nodeIndex = 0 ; nodeIndex < nodes.size(); ++nodeIndex) {
1420    const ExplodedNode *originalNode = nodes[nodeIndex];
1421    if (const ExplodedNode *N = NMap->getMappedNode(originalNode)) {
1422      WS.push(N);
1423      IndexMap[originalNode] = nodeIndex;
1424    }
1425  }
1426
1427  assert(!WS.empty() && "No error node found in the trimmed graph.");
1428
1429  // Create a new (third!) graph with a single path.  This is the graph
1430  // that will be returned to the caller.
1431  ExplodedGraph *GNew = new ExplodedGraph();
1432
1433  // Sometimes the trimmed graph can contain a cycle.  Perform a reverse BFS
1434  // to the root node, and then construct a new graph that contains only
1435  // a single path.
1436  llvm::DenseMap<const void*,unsigned> Visited;
1437
1438  unsigned cnt = 0;
1439  const ExplodedNode *Root = 0;
1440
1441  while (!WS.empty()) {
1442    const ExplodedNode *Node = WS.front();
1443    WS.pop();
1444
1445    if (Visited.find(Node) != Visited.end())
1446      continue;
1447
1448    Visited[Node] = cnt++;
1449
1450    if (Node->pred_empty()) {
1451      Root = Node;
1452      break;
1453    }
1454
1455    for (ExplodedNode::const_pred_iterator I=Node->pred_begin(),
1456         E=Node->pred_end(); I!=E; ++I)
1457      WS.push(*I);
1458  }
1459
1460  assert(Root);
1461
1462  // Now walk from the root down the BFS path, always taking the successor
1463  // with the lowest number.
1464  ExplodedNode *Last = 0, *First = 0;
1465  NodeBackMap *BM = new NodeBackMap();
1466  unsigned NodeIndex = 0;
1467
1468  for ( const ExplodedNode *N = Root ;;) {
1469    // Lookup the number associated with the current node.
1470    llvm::DenseMap<const void*,unsigned>::iterator I = Visited.find(N);
1471    assert(I != Visited.end());
1472
1473    // Create the equivalent node in the new graph with the same state
1474    // and location.
1475    ExplodedNode *NewN = GNew->getNode(N->getLocation(), N->getState());
1476
1477    // Store the mapping to the original node.
1478    llvm::DenseMap<const void*, const void*>::iterator IMitr=InverseMap.find(N);
1479    assert(IMitr != InverseMap.end() && "No mapping to original node.");
1480    (*BM)[NewN] = (const ExplodedNode*) IMitr->second;
1481
1482    // Link up the new node with the previous node.
1483    if (Last)
1484      NewN->addPredecessor(Last, *GNew);
1485
1486    Last = NewN;
1487
1488    // Are we at the final node?
1489    IndexMapTy::iterator IMI =
1490      IndexMap.find((const ExplodedNode*)(IMitr->second));
1491    if (IMI != IndexMap.end()) {
1492      First = NewN;
1493      NodeIndex = IMI->second;
1494      break;
1495    }
1496
1497    // Find the next successor node.  We choose the node that is marked
1498    // with the lowest DFS number.
1499    ExplodedNode::const_succ_iterator SI = N->succ_begin();
1500    ExplodedNode::const_succ_iterator SE = N->succ_end();
1501    N = 0;
1502
1503    for (unsigned MinVal = 0; SI != SE; ++SI) {
1504
1505      I = Visited.find(*SI);
1506
1507      if (I == Visited.end())
1508        continue;
1509
1510      if (!N || I->second < MinVal) {
1511        N = *SI;
1512        MinVal = I->second;
1513      }
1514    }
1515
1516    assert(N);
1517  }
1518
1519  assert(First);
1520
1521  return std::make_pair(std::make_pair(GNew, BM),
1522                        std::make_pair(First, NodeIndex));
1523}
1524
1525/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object
1526///  and collapses PathDiagosticPieces that are expanded by macros.
1527static void CompactPathDiagnostic(PathDiagnostic &PD, const SourceManager& SM) {
1528  typedef std::vector<std::pair<PathDiagnosticMacroPiece*, SourceLocation> >
1529          MacroStackTy;
1530
1531  typedef std::vector<PathDiagnosticPiece*>
1532          PiecesTy;
1533
1534  MacroStackTy MacroStack;
1535  PiecesTy Pieces;
1536
1537  for (PathDiagnostic::iterator I = PD.begin(), E = PD.end(); I!=E; ++I) {
1538    // Get the location of the PathDiagnosticPiece.
1539    const FullSourceLoc Loc = I->getLocation().asLocation();
1540
1541    // Determine the instantiation location, which is the location we group
1542    // related PathDiagnosticPieces.
1543    SourceLocation InstantiationLoc = Loc.isMacroID() ?
1544                                      SM.getExpansionLoc(Loc) :
1545                                      SourceLocation();
1546
1547    if (Loc.isFileID()) {
1548      MacroStack.clear();
1549      Pieces.push_back(&*I);
1550      continue;
1551    }
1552
1553    assert(Loc.isMacroID());
1554
1555    // Is the PathDiagnosticPiece within the same macro group?
1556    if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) {
1557      MacroStack.back().first->push_back(&*I);
1558      continue;
1559    }
1560
1561    // We aren't in the same group.  Are we descending into a new macro
1562    // or are part of an old one?
1563    PathDiagnosticMacroPiece *MacroGroup = 0;
1564
1565    SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ?
1566                                          SM.getExpansionLoc(Loc) :
1567                                          SourceLocation();
1568
1569    // Walk the entire macro stack.
1570    while (!MacroStack.empty()) {
1571      if (InstantiationLoc == MacroStack.back().second) {
1572        MacroGroup = MacroStack.back().first;
1573        break;
1574      }
1575
1576      if (ParentInstantiationLoc == MacroStack.back().second) {
1577        MacroGroup = MacroStack.back().first;
1578        break;
1579      }
1580
1581      MacroStack.pop_back();
1582    }
1583
1584    if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) {
1585      // Create a new macro group and add it to the stack.
1586      PathDiagnosticMacroPiece *NewGroup = new PathDiagnosticMacroPiece(Loc);
1587
1588      if (MacroGroup)
1589        MacroGroup->push_back(NewGroup);
1590      else {
1591        assert(InstantiationLoc.isFileID());
1592        Pieces.push_back(NewGroup);
1593      }
1594
1595      MacroGroup = NewGroup;
1596      MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc));
1597    }
1598
1599    // Finally, add the PathDiagnosticPiece to the group.
1600    MacroGroup->push_back(&*I);
1601  }
1602
1603  // Now take the pieces and construct a new PathDiagnostic.
1604  PD.resetPath(false);
1605
1606  for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I) {
1607    if (PathDiagnosticMacroPiece *MP=dyn_cast<PathDiagnosticMacroPiece>(*I))
1608      if (!MP->containsEvent()) {
1609        delete MP;
1610        continue;
1611      }
1612
1613    PD.push_back(*I);
1614  }
1615}
1616
1617void GRBugReporter::GeneratePathDiagnostic(PathDiagnostic& PD,
1618                        SmallVectorImpl<BugReport *> &bugReports) {
1619
1620  assert(!bugReports.empty());
1621  SmallVector<const ExplodedNode *, 10> errorNodes;
1622  for (SmallVectorImpl<BugReport*>::iterator I = bugReports.begin(),
1623    E = bugReports.end(); I != E; ++I) {
1624      errorNodes.push_back((*I)->getErrorNode());
1625  }
1626
1627  // Construct a new graph that contains only a single path from the error
1628  // node to a root.
1629  const std::pair<std::pair<ExplodedGraph*, NodeBackMap*>,
1630  std::pair<ExplodedNode*, unsigned> >&
1631    GPair = MakeReportGraph(&getGraph(), errorNodes);
1632
1633  // Find the BugReport with the original location.
1634  assert(GPair.second.second < bugReports.size());
1635  BugReport *R = bugReports[GPair.second.second];
1636  assert(R && "No original report found for sliced graph.");
1637
1638  llvm::OwningPtr<ExplodedGraph> ReportGraph(GPair.first.first);
1639  llvm::OwningPtr<NodeBackMap> BackMap(GPair.first.second);
1640  const ExplodedNode *N = GPair.second.first;
1641
1642  // Start building the path diagnostic...
1643  PathDiagnosticBuilder PDB(*this, R, BackMap.get(), getPathDiagnosticClient());
1644
1645  if (PathDiagnosticPiece *Piece = R->getEndPath(PDB, N))
1646    PD.push_back(Piece);
1647  else
1648    return;
1649
1650  // Register node visitors.
1651  R->registerInitialVisitors(PDB, N);
1652  bugreporter::registerNilReceiverVisitor(PDB);
1653  bugreporter::registerConditionVisitor(PDB);
1654
1655  switch (PDB.getGenerationScheme()) {
1656    case PathDiagnosticClient::Extensive:
1657      GenerateExtensivePathDiagnostic(PD, PDB, N);
1658      break;
1659    case PathDiagnosticClient::Minimal:
1660      GenerateMinimalPathDiagnostic(PD, PDB, N);
1661      break;
1662  }
1663}
1664
1665void BugReporter::Register(BugType *BT) {
1666  BugTypes = F.add(BugTypes, BT);
1667}
1668
1669void BugReporter::EmitReport(BugReport* R) {
1670  // Compute the bug report's hash to determine its equivalence class.
1671  llvm::FoldingSetNodeID ID;
1672  R->Profile(ID);
1673
1674  // Lookup the equivance class.  If there isn't one, create it.
1675  BugType& BT = R->getBugType();
1676  Register(&BT);
1677  void *InsertPos;
1678  BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos);
1679
1680  if (!EQ) {
1681    EQ = new BugReportEquivClass(R);
1682    EQClasses.InsertNode(EQ, InsertPos);
1683  }
1684  else
1685    EQ->AddReport(R);
1686}
1687
1688
1689//===----------------------------------------------------------------------===//
1690// Emitting reports in equivalence classes.
1691//===----------------------------------------------------------------------===//
1692
1693namespace {
1694struct FRIEC_WLItem {
1695  const ExplodedNode *N;
1696  ExplodedNode::const_succ_iterator I, E;
1697
1698  FRIEC_WLItem(const ExplodedNode *n)
1699  : N(n), I(N->succ_begin()), E(N->succ_end()) {}
1700};
1701}
1702
1703static BugReport *
1704FindReportInEquivalenceClass(BugReportEquivClass& EQ,
1705                             SmallVectorImpl<BugReport*> &bugReports) {
1706
1707  BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end();
1708  assert(I != E);
1709  BugReport *R = *I;
1710  BugType& BT = R->getBugType();
1711
1712  // If we don't need to suppress any of the nodes because they are
1713  // post-dominated by a sink, simply add all the nodes in the equivalence class
1714  // to 'Nodes'.  Any of the reports will serve as a "representative" report.
1715  if (!BT.isSuppressOnSink()) {
1716    for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) {
1717      const ExplodedNode *N = I->getErrorNode();
1718      if (N) {
1719        R = *I;
1720        bugReports.push_back(R);
1721      }
1722    }
1723    return R;
1724  }
1725
1726  // For bug reports that should be suppressed when all paths are post-dominated
1727  // by a sink node, iterate through the reports in the equivalence class
1728  // until we find one that isn't post-dominated (if one exists).  We use a
1729  // DFS traversal of the ExplodedGraph to find a non-sink node.  We could write
1730  // this as a recursive function, but we don't want to risk blowing out the
1731  // stack for very long paths.
1732  BugReport *exampleReport = 0;
1733
1734  for (; I != E; ++I) {
1735    R = *I;
1736    const ExplodedNode *errorNode = R->getErrorNode();
1737
1738    if (!errorNode)
1739      continue;
1740    if (errorNode->isSink()) {
1741      assert(false &&
1742           "BugType::isSuppressSink() should not be 'true' for sink end nodes");
1743      return 0;
1744    }
1745    // No successors?  By definition this nodes isn't post-dominated by a sink.
1746    if (errorNode->succ_empty()) {
1747      bugReports.push_back(R);
1748      if (!exampleReport)
1749        exampleReport = R;
1750      continue;
1751    }
1752
1753    // At this point we know that 'N' is not a sink and it has at least one
1754    // successor.  Use a DFS worklist to find a non-sink end-of-path node.
1755    typedef FRIEC_WLItem WLItem;
1756    typedef SmallVector<WLItem, 10> DFSWorkList;
1757    llvm::DenseMap<const ExplodedNode *, unsigned> Visited;
1758
1759    DFSWorkList WL;
1760    WL.push_back(errorNode);
1761    Visited[errorNode] = 1;
1762
1763    while (!WL.empty()) {
1764      WLItem &WI = WL.back();
1765      assert(!WI.N->succ_empty());
1766
1767      for (; WI.I != WI.E; ++WI.I) {
1768        const ExplodedNode *Succ = *WI.I;
1769        // End-of-path node?
1770        if (Succ->succ_empty()) {
1771          // If we found an end-of-path node that is not a sink.
1772          if (!Succ->isSink()) {
1773            bugReports.push_back(R);
1774            if (!exampleReport)
1775              exampleReport = R;
1776            WL.clear();
1777            break;
1778          }
1779          // Found a sink?  Continue on to the next successor.
1780          continue;
1781        }
1782        // Mark the successor as visited.  If it hasn't been explored,
1783        // enqueue it to the DFS worklist.
1784        unsigned &mark = Visited[Succ];
1785        if (!mark) {
1786          mark = 1;
1787          WL.push_back(Succ);
1788          break;
1789        }
1790      }
1791
1792      // The worklist may have been cleared at this point.  First
1793      // check if it is empty before checking the last item.
1794      if (!WL.empty() && &WL.back() == &WI)
1795        WL.pop_back();
1796    }
1797  }
1798
1799  // ExampleReport will be NULL if all the nodes in the equivalence class
1800  // were post-dominated by sinks.
1801  return exampleReport;
1802}
1803
1804//===----------------------------------------------------------------------===//
1805// DiagnosticCache.  This is a hack to cache analyzer diagnostics.  It
1806// uses global state, which eventually should go elsewhere.
1807//===----------------------------------------------------------------------===//
1808namespace {
1809class DiagCacheItem : public llvm::FoldingSetNode {
1810  llvm::FoldingSetNodeID ID;
1811public:
1812  DiagCacheItem(BugReport *R, PathDiagnostic *PD) {
1813    ID.AddString(R->getBugType().getName());
1814    ID.AddString(R->getBugType().getCategory());
1815    ID.AddString(R->getDescription());
1816    ID.AddInteger(R->getLocation().getRawEncoding());
1817    PD->Profile(ID);
1818  }
1819
1820  void Profile(llvm::FoldingSetNodeID &id) {
1821    id = ID;
1822  }
1823
1824  llvm::FoldingSetNodeID &getID() { return ID; }
1825};
1826}
1827
1828static bool IsCachedDiagnostic(BugReport *R, PathDiagnostic *PD) {
1829  // FIXME: Eventually this diagnostic cache should reside in something
1830  // like AnalysisManager instead of being a static variable.  This is
1831  // really unsafe in the long term.
1832  typedef llvm::FoldingSet<DiagCacheItem> DiagnosticCache;
1833  static DiagnosticCache DC;
1834
1835  void *InsertPos;
1836  DiagCacheItem *Item = new DiagCacheItem(R, PD);
1837
1838  if (DC.FindNodeOrInsertPos(Item->getID(), InsertPos)) {
1839    delete Item;
1840    return true;
1841  }
1842
1843  DC.InsertNode(Item, InsertPos);
1844  return false;
1845}
1846
1847void BugReporter::FlushReport(BugReportEquivClass& EQ) {
1848  SmallVector<BugReport*, 10> bugReports;
1849  BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports);
1850  if (!exampleReport)
1851    return;
1852
1853  PathDiagnosticClient* PD = getPathDiagnosticClient();
1854
1855  // FIXME: Make sure we use the 'R' for the path that was actually used.
1856  // Probably doesn't make a difference in practice.
1857  BugType& BT = exampleReport->getBugType();
1858
1859  llvm::OwningPtr<PathDiagnostic>
1860    D(new PathDiagnostic(exampleReport->getBugType().getName(),
1861                         !PD || PD->useVerboseDescription()
1862                         ? exampleReport->getDescription()
1863                         : exampleReport->getShortDescription(),
1864                         BT.getCategory()));
1865
1866  if (!bugReports.empty())
1867    GeneratePathDiagnostic(*D.get(), bugReports);
1868
1869  if (IsCachedDiagnostic(exampleReport, D.get()))
1870    return;
1871
1872  // Get the meta data.
1873  std::pair<const char**, const char**> Meta =
1874    exampleReport->getExtraDescriptiveText();
1875  for (const char** s = Meta.first; s != Meta.second; ++s)
1876    D->addMeta(*s);
1877
1878  // Emit a summary diagnostic to the regular Diagnostics engine.
1879  BugReport::ranges_iterator Beg, End;
1880  llvm::tie(Beg, End) = exampleReport->getRanges();
1881  Diagnostic &Diag = getDiagnostic();
1882  FullSourceLoc L(exampleReport->getLocation(), getSourceManager());
1883
1884  // Search the description for '%', as that will be interpretted as a
1885  // format character by FormatDiagnostics.
1886  StringRef desc = exampleReport->getShortDescription();
1887  unsigned ErrorDiag;
1888  {
1889    llvm::SmallString<512> TmpStr;
1890    llvm::raw_svector_ostream Out(TmpStr);
1891    for (StringRef::iterator I=desc.begin(), E=desc.end(); I!=E; ++I)
1892      if (*I == '%')
1893        Out << "%%";
1894      else
1895        Out << *I;
1896
1897    Out.flush();
1898    ErrorDiag = Diag.getCustomDiagID(Diagnostic::Warning, TmpStr);
1899  }
1900
1901  {
1902    DiagnosticBuilder diagBuilder = Diag.Report(L, ErrorDiag);
1903    for (BugReport::ranges_iterator I = Beg; I != End; ++I)
1904      diagBuilder << *I;
1905  }
1906
1907  // Emit a full diagnostic for the path if we have a PathDiagnosticClient.
1908  if (!PD)
1909    return;
1910
1911  if (D->empty()) {
1912    PathDiagnosticPiece *piece =
1913      new PathDiagnosticEventPiece(L, exampleReport->getDescription());
1914
1915    for ( ; Beg != End; ++Beg) piece->addRange(*Beg);
1916    D->push_back(piece);
1917  }
1918
1919  PD->HandlePathDiagnostic(D.take());
1920}
1921
1922void BugReporter::EmitBasicReport(StringRef name, StringRef str,
1923                                  SourceLocation Loc,
1924                                  SourceRange* RBeg, unsigned NumRanges) {
1925  EmitBasicReport(name, "", str, Loc, RBeg, NumRanges);
1926}
1927
1928void BugReporter::EmitBasicReport(StringRef name,
1929                                  StringRef category,
1930                                  StringRef str, SourceLocation Loc,
1931                                  SourceRange* RBeg, unsigned NumRanges) {
1932
1933  // 'BT' is owned by BugReporter.
1934  BugType *BT = getBugTypeForName(name, category);
1935  FullSourceLoc L = getContext().getFullLoc(Loc);
1936  BugReport *R = new DiagBugReport(*BT, str, L);
1937  for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg);
1938  EmitReport(R);
1939}
1940
1941BugType *BugReporter::getBugTypeForName(StringRef name,
1942                                        StringRef category) {
1943  llvm::SmallString<136> fullDesc;
1944  llvm::raw_svector_ostream(fullDesc) << name << ":" << category;
1945  llvm::StringMapEntry<BugType *> &
1946      entry = StrBugTypes.GetOrCreateValue(fullDesc);
1947  BugType *BT = entry.getValue();
1948  if (!BT) {
1949    BT = new BugType(name, category);
1950    entry.setValue(BT);
1951  }
1952  return BT;
1953}
1954