BugReporter.cpp revision 9c378f705405d37f49795d5e915989de774fe11f 
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*
350GetMostRecentVarDeclBinding(const ExplodedNode *N,
351                            GRStateManager& VMgr, 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 GRState *PrevSt;
387  const Stmt *S;
388  GRStateManager& VMgr;
389  const ExplodedNode *Pred;
390  PathDiagnostic& PD;
391  BugReporter& BR;
392
393public:
394
395  NotableSymbolHandler(SymbolRef sym, const GRState *prevst, const Stmt *s,
396                       GRStateManager& vmgr, const ExplodedNode *pred,
397                       PathDiagnostic& pd, BugReporter& br)
398  : Sym(sym), PrevSt(prevst), S(s), VMgr(vmgr), Pred(pred), PD(pd), BR(br) {}
399
400  bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R,
401                     SVal V) {
402
403    SymbolRef ScanSym = V.getAsSymbol();
404
405    if (ScanSym != Sym)
406      return true;
407
408    // Check if the previous state has this binding.
409    SVal X = PrevSt->getSVal(loc::MemRegionVal(R));
410
411    if (X == V) // Same binding?
412      return true;
413
414    // Different binding.  Only handle assignments for now.  We don't pull
415    // this check out of the loop because we will eventually handle other
416    // cases.
417
418    VarDecl *VD = 0;
419
420    if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) {
421      if (!B->isAssignmentOp())
422        return true;
423
424      // What variable did we assign to?
425      DeclRefExpr *DR = dyn_cast<DeclRefExpr>(B->getLHS()->IgnoreParenCasts());
426
427      if (!DR)
428        return true;
429
430      VD = dyn_cast<VarDecl>(DR->getDecl());
431    }
432    else if (const DeclStmt *DS = dyn_cast<DeclStmt>(S)) {
433      // FIXME: Eventually CFGs won't have DeclStmts.  Right now we
434      //  assume that each DeclStmt has a single Decl.  This invariant
435      //  holds by construction in the CFG.
436      VD = dyn_cast<VarDecl>(*DS->decl_begin());
437    }
438
439    if (!VD)
440      return true;
441
442    // What is the most recently referenced variable with this binding?
443    const VarDecl *MostRecent = GetMostRecentVarDeclBinding(Pred, VMgr, V);
444
445    if (!MostRecent)
446      return true;
447
448    // Create the diagnostic.
449    FullSourceLoc L(S->getLocStart(), BR.getSourceManager());
450
451    if (Loc::isLocType(VD->getType())) {
452      std::string msg = "'" + std::string(VD->getNameAsString()) +
453      "' now aliases '" + MostRecent->getNameAsString() + "'";
454
455      PD.push_front(new PathDiagnosticEventPiece(L, msg));
456    }
457
458    return true;
459  }
460};
461}
462
463static void HandleNotableSymbol(const ExplodedNode *N,
464                                const Stmt *S,
465                                SymbolRef Sym, BugReporter& BR,
466                                PathDiagnostic& PD) {
467
468  const ExplodedNode *Pred = N->pred_empty() ? 0 : *N->pred_begin();
469  const GRState *PrevSt = Pred ? Pred->getState() : 0;
470
471  if (!PrevSt)
472    return;
473
474  // Look at the region bindings of the current state that map to the
475  // specified symbol.  Are any of them not in the previous state?
476  GRStateManager& VMgr = cast<GRBugReporter>(BR).getStateManager();
477  NotableSymbolHandler H(Sym, PrevSt, S, VMgr, Pred, PD, BR);
478  cast<GRBugReporter>(BR).getStateManager().iterBindings(N->getState(), H);
479}
480
481namespace {
482class ScanNotableSymbols
483: public StoreManager::BindingsHandler {
484
485  llvm::SmallSet<SymbolRef, 10> AlreadyProcessed;
486  const ExplodedNode *N;
487  const Stmt *S;
488  GRBugReporter& BR;
489  PathDiagnostic& PD;
490
491public:
492  ScanNotableSymbols(const ExplodedNode *n, const Stmt *s,
493                     GRBugReporter& br, PathDiagnostic& pd)
494  : N(n), S(s), BR(br), PD(pd) {}
495
496  bool HandleBinding(StoreManager& SMgr, Store store,
497                     const MemRegion* R, SVal V) {
498
499    SymbolRef ScanSym = V.getAsSymbol();
500
501    if (!ScanSym)
502      return true;
503
504    if (!BR.isNotable(ScanSym))
505      return true;
506
507    if (AlreadyProcessed.count(ScanSym))
508      return true;
509
510    AlreadyProcessed.insert(ScanSym);
511
512    HandleNotableSymbol(N, S, ScanSym, BR, PD);
513    return true;
514  }
515};
516} // end anonymous namespace
517
518//===----------------------------------------------------------------------===//
519// "Minimal" path diagnostic generation algorithm.
520//===----------------------------------------------------------------------===//
521
522static void CompactPathDiagnostic(PathDiagnostic &PD, const SourceManager& SM);
523
524static void GenerateMinimalPathDiagnostic(PathDiagnostic& PD,
525                                          PathDiagnosticBuilder &PDB,
526                                          const ExplodedNode *N) {
527
528  SourceManager& SMgr = PDB.getSourceManager();
529  const ExplodedNode *NextNode = N->pred_empty()
530                                        ? NULL : *(N->pred_begin());
531  while (NextNode) {
532    N = NextNode;
533    NextNode = GetPredecessorNode(N);
534
535    ProgramPoint P = N->getLocation();
536
537    if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
538      const CFGBlock *Src = BE->getSrc();
539      const CFGBlock *Dst = BE->getDst();
540      const Stmt *T = Src->getTerminator();
541
542      if (!T)
543        continue;
544
545      FullSourceLoc Start(T->getLocStart(), SMgr);
546
547      switch (T->getStmtClass()) {
548        default:
549          break;
550
551        case Stmt::GotoStmtClass:
552        case Stmt::IndirectGotoStmtClass: {
553          const Stmt *S = GetNextStmt(N);
554
555          if (!S)
556            continue;
557
558          std::string sbuf;
559          llvm::raw_string_ostream os(sbuf);
560          const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S);
561
562          os << "Control jumps to line "
563          << End.asLocation().getExpansionLineNumber();
564          PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
565                                                           os.str()));
566          break;
567        }
568
569        case Stmt::SwitchStmtClass: {
570          // Figure out what case arm we took.
571          std::string sbuf;
572          llvm::raw_string_ostream os(sbuf);
573
574          if (const Stmt *S = Dst->getLabel()) {
575            PathDiagnosticLocation End(S, SMgr);
576
577            switch (S->getStmtClass()) {
578              default:
579                os << "No cases match in the switch statement. "
580                "Control jumps to line "
581                << End.asLocation().getExpansionLineNumber();
582                break;
583              case Stmt::DefaultStmtClass:
584                os << "Control jumps to the 'default' case at line "
585                << End.asLocation().getExpansionLineNumber();
586                break;
587
588              case Stmt::CaseStmtClass: {
589                os << "Control jumps to 'case ";
590                const CaseStmt *Case = cast<CaseStmt>(S);
591                const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
592
593                // Determine if it is an enum.
594                bool GetRawInt = true;
595
596                if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) {
597                  // FIXME: Maybe this should be an assertion.  Are there cases
598                  // were it is not an EnumConstantDecl?
599                  const EnumConstantDecl *D =
600                    dyn_cast<EnumConstantDecl>(DR->getDecl());
601
602                  if (D) {
603                    GetRawInt = false;
604                    os << D;
605                  }
606                }
607
608                if (GetRawInt)
609                  os << LHS->EvaluateAsInt(PDB.getASTContext());
610
611                os << ":'  at line "
612                << End.asLocation().getExpansionLineNumber();
613                break;
614              }
615            }
616            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
617                                                             os.str()));
618          }
619          else {
620            os << "'Default' branch taken. ";
621            const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N);
622            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
623                                                             os.str()));
624          }
625
626          break;
627        }
628
629        case Stmt::BreakStmtClass:
630        case Stmt::ContinueStmtClass: {
631          std::string sbuf;
632          llvm::raw_string_ostream os(sbuf);
633          PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
634          PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
635                                                           os.str()));
636          break;
637        }
638
639          // Determine control-flow for ternary '?'.
640        case Stmt::BinaryConditionalOperatorClass:
641        case Stmt::ConditionalOperatorClass: {
642          std::string sbuf;
643          llvm::raw_string_ostream os(sbuf);
644          os << "'?' condition is ";
645
646          if (*(Src->succ_begin()+1) == Dst)
647            os << "false";
648          else
649            os << "true";
650
651          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
652
653          if (const Stmt *S = End.asStmt())
654            End = PDB.getEnclosingStmtLocation(S);
655
656          PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
657                                                           os.str()));
658          break;
659        }
660
661          // Determine control-flow for short-circuited '&&' and '||'.
662        case Stmt::BinaryOperatorClass: {
663          if (!PDB.supportsLogicalOpControlFlow())
664            break;
665
666          const BinaryOperator *B = cast<BinaryOperator>(T);
667          std::string sbuf;
668          llvm::raw_string_ostream os(sbuf);
669          os << "Left side of '";
670
671          if (B->getOpcode() == BO_LAnd) {
672            os << "&&" << "' is ";
673
674            if (*(Src->succ_begin()+1) == Dst) {
675              os << "false";
676              PathDiagnosticLocation End(B->getLHS(), SMgr);
677              PathDiagnosticLocation Start(B->getOperatorLoc(), SMgr);
678              PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
679                                                               os.str()));
680            }
681            else {
682              os << "true";
683              PathDiagnosticLocation Start(B->getLHS(), SMgr);
684              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
685              PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
686                                                               os.str()));
687            }
688          }
689          else {
690            assert(B->getOpcode() == BO_LOr);
691            os << "||" << "' is ";
692
693            if (*(Src->succ_begin()+1) == Dst) {
694              os << "false";
695              PathDiagnosticLocation Start(B->getLHS(), SMgr);
696              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
697              PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
698                                                               os.str()));
699            }
700            else {
701              os << "true";
702              PathDiagnosticLocation End(B->getLHS(), SMgr);
703              PathDiagnosticLocation Start(B->getOperatorLoc(), SMgr);
704              PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
705                                                               os.str()));
706            }
707          }
708
709          break;
710        }
711
712        case Stmt::DoStmtClass:  {
713          if (*(Src->succ_begin()) == Dst) {
714            std::string sbuf;
715            llvm::raw_string_ostream os(sbuf);
716
717            os << "Loop condition is true. ";
718            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
719
720            if (const Stmt *S = End.asStmt())
721              End = PDB.getEnclosingStmtLocation(S);
722
723            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
724                                                             os.str()));
725          }
726          else {
727            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
728
729            if (const Stmt *S = End.asStmt())
730              End = PDB.getEnclosingStmtLocation(S);
731
732            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
733                              "Loop condition is false.  Exiting loop"));
734          }
735
736          break;
737        }
738
739        case Stmt::WhileStmtClass:
740        case Stmt::ForStmtClass: {
741          if (*(Src->succ_begin()+1) == Dst) {
742            std::string sbuf;
743            llvm::raw_string_ostream os(sbuf);
744
745            os << "Loop condition is false. ";
746            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
747            if (const Stmt *S = End.asStmt())
748              End = PDB.getEnclosingStmtLocation(S);
749
750            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
751                                                             os.str()));
752          }
753          else {
754            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
755            if (const Stmt *S = End.asStmt())
756              End = PDB.getEnclosingStmtLocation(S);
757
758            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
759                            "Loop condition is true.  Entering loop body"));
760          }
761
762          break;
763        }
764
765        case Stmt::IfStmtClass: {
766          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
767
768          if (const Stmt *S = End.asStmt())
769            End = PDB.getEnclosingStmtLocation(S);
770
771          if (*(Src->succ_begin()+1) == Dst)
772            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
773                                                        "Taking false branch"));
774          else
775            PD.push_front(new PathDiagnosticControlFlowPiece(Start, End,
776                                                         "Taking true branch"));
777
778          break;
779        }
780      }
781    }
782
783    if (NextNode) {
784      for (BugReporterContext::visitor_iterator I = PDB.visitor_begin(),
785           E = PDB.visitor_end(); I!=E; ++I) {
786        if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB))
787          PD.push_front(p);
788      }
789    }
790
791    if (const PostStmt *PS = dyn_cast<PostStmt>(&P)) {
792      // Scan the region bindings, and see if a "notable" symbol has a new
793      // lval binding.
794      ScanNotableSymbols SNS(N, PS->getStmt(), PDB.getBugReporter(), PD);
795      PDB.getStateManager().iterBindings(N->getState(), SNS);
796    }
797  }
798
799  // After constructing the full PathDiagnostic, do a pass over it to compact
800  // PathDiagnosticPieces that occur within a macro.
801  CompactPathDiagnostic(PD, PDB.getSourceManager());
802}
803
804//===----------------------------------------------------------------------===//
805// "Extensive" PathDiagnostic generation.
806//===----------------------------------------------------------------------===//
807
808static bool IsControlFlowExpr(const Stmt *S) {
809  const Expr *E = dyn_cast<Expr>(S);
810
811  if (!E)
812    return false;
813
814  E = E->IgnoreParenCasts();
815
816  if (isa<AbstractConditionalOperator>(E))
817    return true;
818
819  if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E))
820    if (B->isLogicalOp())
821      return true;
822
823  return false;
824}
825
826namespace {
827class ContextLocation : public PathDiagnosticLocation {
828  bool IsDead;
829public:
830  ContextLocation(const PathDiagnosticLocation &L, bool isdead = false)
831    : PathDiagnosticLocation(L), IsDead(isdead) {}
832
833  void markDead() { IsDead = true; }
834  bool isDead() const { return IsDead; }
835};
836
837class EdgeBuilder {
838  std::vector<ContextLocation> CLocs;
839  typedef std::vector<ContextLocation>::iterator iterator;
840  PathDiagnostic &PD;
841  PathDiagnosticBuilder &PDB;
842  PathDiagnosticLocation PrevLoc;
843
844  bool IsConsumedExpr(const PathDiagnosticLocation &L);
845
846  bool containsLocation(const PathDiagnosticLocation &Container,
847                        const PathDiagnosticLocation &Containee);
848
849  PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L);
850
851  PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L,
852                                         bool firstCharOnly = false) {
853    if (const Stmt *S = L.asStmt()) {
854      const Stmt *Original = S;
855      while (1) {
856        // Adjust the location for some expressions that are best referenced
857        // by one of their subexpressions.
858        switch (S->getStmtClass()) {
859          default:
860            break;
861          case Stmt::ParenExprClass:
862          case Stmt::GenericSelectionExprClass:
863            S = cast<Expr>(S)->IgnoreParens();
864            firstCharOnly = true;
865            continue;
866          case Stmt::BinaryConditionalOperatorClass:
867          case Stmt::ConditionalOperatorClass:
868            S = cast<AbstractConditionalOperator>(S)->getCond();
869            firstCharOnly = true;
870            continue;
871          case Stmt::ChooseExprClass:
872            S = cast<ChooseExpr>(S)->getCond();
873            firstCharOnly = true;
874            continue;
875          case Stmt::BinaryOperatorClass:
876            S = cast<BinaryOperator>(S)->getLHS();
877            firstCharOnly = true;
878            continue;
879        }
880
881        break;
882      }
883
884      if (S != Original)
885        L = PathDiagnosticLocation(S, L.getManager());
886    }
887
888    if (firstCharOnly)
889      L = PathDiagnosticLocation(L.asLocation());
890
891    return L;
892  }
893
894  void popLocation() {
895    if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) {
896      // For contexts, we only one the first character as the range.
897      rawAddEdge(cleanUpLocation(CLocs.back(), true));
898    }
899    CLocs.pop_back();
900  }
901
902public:
903  EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb)
904    : PD(pd), PDB(pdb) {
905
906      // If the PathDiagnostic already has pieces, add the enclosing statement
907      // of the first piece as a context as well.
908      if (!PD.empty()) {
909        PrevLoc = PD.begin()->getLocation();
910
911        if (const Stmt *S = PrevLoc.asStmt())
912          addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
913      }
914  }
915
916  ~EdgeBuilder() {
917    while (!CLocs.empty()) popLocation();
918
919    // Finally, add an initial edge from the start location of the first
920    // statement (if it doesn't already exist).
921    // FIXME: Should handle CXXTryStmt if analyser starts supporting C++.
922    if (const CompoundStmt *CS =
923          dyn_cast_or_null<CompoundStmt>(PDB.getCodeDecl().getBody()))
924      if (!CS->body_empty()) {
925        SourceLocation Loc = (*CS->body_begin())->getLocStart();
926        rawAddEdge(PathDiagnosticLocation(Loc, PDB.getSourceManager()));
927      }
928
929  }
930
931  void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false);
932
933  void rawAddEdge(PathDiagnosticLocation NewLoc);
934
935  void addContext(const Stmt *S);
936  void addExtendedContext(const Stmt *S);
937};
938} // end anonymous namespace
939
940
941PathDiagnosticLocation
942EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) {
943  if (const Stmt *S = L.asStmt()) {
944    if (IsControlFlowExpr(S))
945      return L;
946
947    return PDB.getEnclosingStmtLocation(S);
948  }
949
950  return L;
951}
952
953bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container,
954                                   const PathDiagnosticLocation &Containee) {
955
956  if (Container == Containee)
957    return true;
958
959  if (Container.asDecl())
960    return true;
961
962  if (const Stmt *S = Containee.asStmt())
963    if (const Stmt *ContainerS = Container.asStmt()) {
964      while (S) {
965        if (S == ContainerS)
966          return true;
967        S = PDB.getParent(S);
968      }
969      return false;
970    }
971
972  // Less accurate: compare using source ranges.
973  SourceRange ContainerR = Container.asRange();
974  SourceRange ContaineeR = Containee.asRange();
975
976  SourceManager &SM = PDB.getSourceManager();
977  SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin());
978  SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd());
979  SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin());
980  SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd());
981
982  unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg);
983  unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd);
984  unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg);
985  unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd);
986
987  assert(ContainerBegLine <= ContainerEndLine);
988  assert(ContaineeBegLine <= ContaineeEndLine);
989
990  return (ContainerBegLine <= ContaineeBegLine &&
991          ContainerEndLine >= ContaineeEndLine &&
992          (ContainerBegLine != ContaineeBegLine ||
993           SM.getExpansionColumnNumber(ContainerRBeg) <=
994           SM.getExpansionColumnNumber(ContaineeRBeg)) &&
995          (ContainerEndLine != ContaineeEndLine ||
996           SM.getExpansionColumnNumber(ContainerREnd) >=
997           SM.getExpansionColumnNumber(ContainerREnd)));
998}
999
1000void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) {
1001  if (!PrevLoc.isValid()) {
1002    PrevLoc = NewLoc;
1003    return;
1004  }
1005
1006  const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc);
1007  const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc);
1008
1009  if (NewLocClean.asLocation() == PrevLocClean.asLocation())
1010    return;
1011
1012  // FIXME: Ignore intra-macro edges for now.
1013  if (NewLocClean.asLocation().getExpansionLoc() ==
1014      PrevLocClean.asLocation().getExpansionLoc())
1015    return;
1016
1017  PD.push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean));
1018  PrevLoc = NewLoc;
1019}
1020
1021void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd) {
1022
1023  if (!alwaysAdd && NewLoc.asLocation().isMacroID())
1024    return;
1025
1026  const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc);
1027
1028  while (!CLocs.empty()) {
1029    ContextLocation &TopContextLoc = CLocs.back();
1030
1031    // Is the top location context the same as the one for the new location?
1032    if (TopContextLoc == CLoc) {
1033      if (alwaysAdd) {
1034        if (IsConsumedExpr(TopContextLoc) &&
1035            !IsControlFlowExpr(TopContextLoc.asStmt()))
1036            TopContextLoc.markDead();
1037
1038        rawAddEdge(NewLoc);
1039      }
1040
1041      return;
1042    }
1043
1044    if (containsLocation(TopContextLoc, CLoc)) {
1045      if (alwaysAdd) {
1046        rawAddEdge(NewLoc);
1047
1048        if (IsConsumedExpr(CLoc) && !IsControlFlowExpr(CLoc.asStmt())) {
1049          CLocs.push_back(ContextLocation(CLoc, true));
1050          return;
1051        }
1052      }
1053
1054      CLocs.push_back(CLoc);
1055      return;
1056    }
1057
1058    // Context does not contain the location.  Flush it.
1059    popLocation();
1060  }
1061
1062  // If we reach here, there is no enclosing context.  Just add the edge.
1063  rawAddEdge(NewLoc);
1064}
1065
1066bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) {
1067  if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt()))
1068    return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X);
1069
1070  return false;
1071}
1072
1073void EdgeBuilder::addExtendedContext(const Stmt *S) {
1074  if (!S)
1075    return;
1076
1077  const Stmt *Parent = PDB.getParent(S);
1078  while (Parent) {
1079    if (isa<CompoundStmt>(Parent))
1080      Parent = PDB.getParent(Parent);
1081    else
1082      break;
1083  }
1084
1085  if (Parent) {
1086    switch (Parent->getStmtClass()) {
1087      case Stmt::DoStmtClass:
1088      case Stmt::ObjCAtSynchronizedStmtClass:
1089        addContext(Parent);
1090      default:
1091        break;
1092    }
1093  }
1094
1095  addContext(S);
1096}
1097
1098void EdgeBuilder::addContext(const Stmt *S) {
1099  if (!S)
1100    return;
1101
1102  PathDiagnosticLocation L(S, PDB.getSourceManager());
1103
1104  while (!CLocs.empty()) {
1105    const PathDiagnosticLocation &TopContextLoc = CLocs.back();
1106
1107    // Is the top location context the same as the one for the new location?
1108    if (TopContextLoc == L)
1109      return;
1110
1111    if (containsLocation(TopContextLoc, L)) {
1112      CLocs.push_back(L);
1113      return;
1114    }
1115
1116    // Context does not contain the location.  Flush it.
1117    popLocation();
1118  }
1119
1120  CLocs.push_back(L);
1121}
1122
1123static void GenerateExtensivePathDiagnostic(PathDiagnostic& PD,
1124                                            PathDiagnosticBuilder &PDB,
1125                                            const ExplodedNode *N) {
1126  EdgeBuilder EB(PD, PDB);
1127
1128  const ExplodedNode *NextNode = N->pred_empty() ? NULL : *(N->pred_begin());
1129  while (NextNode) {
1130    N = NextNode;
1131    NextNode = GetPredecessorNode(N);
1132    ProgramPoint P = N->getLocation();
1133
1134    do {
1135      // Block edges.
1136      if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
1137        const CFGBlock &Blk = *BE->getSrc();
1138        const Stmt *Term = Blk.getTerminator();
1139
1140        // Are we jumping to the head of a loop?  Add a special diagnostic.
1141        if (const Stmt *Loop = BE->getDst()->getLoopTarget()) {
1142          PathDiagnosticLocation L(Loop, PDB.getSourceManager());
1143          const CompoundStmt *CS = NULL;
1144
1145          if (!Term) {
1146            if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
1147              CS = dyn_cast<CompoundStmt>(FS->getBody());
1148            else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
1149              CS = dyn_cast<CompoundStmt>(WS->getBody());
1150          }
1151
1152          PathDiagnosticEventPiece *p =
1153            new PathDiagnosticEventPiece(L,
1154                                        "Looping back to the head of the loop");
1155
1156          EB.addEdge(p->getLocation(), true);
1157          PD.push_front(p);
1158
1159          if (CS) {
1160            PathDiagnosticLocation BL(CS->getRBracLoc(),
1161                                      PDB.getSourceManager());
1162            BL = PathDiagnosticLocation(BL.asLocation());
1163            EB.addEdge(BL);
1164          }
1165        }
1166
1167        if (Term)
1168          EB.addContext(Term);
1169
1170        break;
1171      }
1172
1173      if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
1174        if (const CFGStmt *S = BE->getFirstElement().getAs<CFGStmt>()) {
1175          const Stmt *stmt = S->getStmt();
1176          if (IsControlFlowExpr(stmt)) {
1177            // Add the proper context for '&&', '||', and '?'.
1178            EB.addContext(stmt);
1179          }
1180          else
1181            EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt());
1182        }
1183
1184        break;
1185      }
1186    } while (0);
1187
1188    if (!NextNode)
1189      continue;
1190
1191    for (BugReporterContext::visitor_iterator I = PDB.visitor_begin(),
1192         E = PDB.visitor_end(); I!=E; ++I) {
1193      if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB)) {
1194        const PathDiagnosticLocation &Loc = p->getLocation();
1195        EB.addEdge(Loc, true);
1196        PD.push_front(p);
1197        if (const Stmt *S = Loc.asStmt())
1198          EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
1199      }
1200    }
1201  }
1202}
1203
1204//===----------------------------------------------------------------------===//
1205// Methods for BugType and subclasses.
1206//===----------------------------------------------------------------------===//
1207BugType::~BugType() { }
1208
1209void BugType::FlushReports(BugReporter &BR) {}
1210
1211//===----------------------------------------------------------------------===//
1212// Methods for BugReport and subclasses.
1213//===----------------------------------------------------------------------===//
1214BugReport::~BugReport() {}
1215RangedBugReport::~RangedBugReport() {}
1216
1217const Stmt *BugReport::getStmt() const {
1218  ProgramPoint ProgP = ErrorNode->getLocation();
1219  const Stmt *S = NULL;
1220
1221  if (BlockEntrance *BE = dyn_cast<BlockEntrance>(&ProgP)) {
1222    CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit();
1223    if (BE->getBlock() == &Exit)
1224      S = GetPreviousStmt(ErrorNode);
1225  }
1226  if (!S)
1227    S = GetStmt(ProgP);
1228
1229  return S;
1230}
1231
1232PathDiagnosticPiece*
1233BugReport::getEndPath(BugReporterContext &BRC,
1234                      const ExplodedNode *EndPathNode) {
1235
1236  const ProgramPoint &PP = EndPathNode->getLocation();
1237  PathDiagnosticLocation L;
1238
1239  if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&PP)) {
1240    const CFGBlock *block = BE->getBlock();
1241    if (block->getBlockID() == 0) {
1242      L = PathDiagnosticLocation(
1243          EndPathNode->getLocationContext()->getDecl()->getBodyRBrace(),
1244          BRC.getSourceManager());
1245    }
1246  }
1247
1248  if (!L.isValid()) {
1249    const Stmt *S = getStmt();
1250
1251    if (!S)
1252      return NULL;
1253
1254    L = PathDiagnosticLocation(S, BRC.getSourceManager());
1255  }
1256
1257  BugReport::ranges_iterator Beg, End;
1258  llvm::tie(Beg, End) = getRanges();
1259
1260  // Only add the statement itself as a range if we didn't specify any
1261  // special ranges for this report.
1262  PathDiagnosticPiece *P = new PathDiagnosticEventPiece(L, getDescription(),
1263                                                        Beg == End);
1264
1265  for (; Beg != End; ++Beg)
1266    P->addRange(*Beg);
1267
1268  return P;
1269}
1270
1271std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator>
1272BugReport::getRanges() const {
1273  if (const Expr *E = dyn_cast_or_null<Expr>(getStmt())) {
1274    R = E->getSourceRange();
1275    assert(R.isValid());
1276    return std::make_pair(&R, &R+1);
1277  }
1278  else
1279    return std::make_pair(ranges_iterator(), ranges_iterator());
1280}
1281
1282SourceLocation BugReport::getLocation() const {
1283  if (ErrorNode)
1284    if (const Stmt *S = GetCurrentOrPreviousStmt(ErrorNode)) {
1285      // For member expressions, return the location of the '.' or '->'.
1286      if (const MemberExpr *ME = dyn_cast<MemberExpr>(S))
1287        return ME->getMemberLoc();
1288      // For binary operators, return the location of the operator.
1289      if (const BinaryOperator *B = dyn_cast<BinaryOperator>(S))
1290        return B->getOperatorLoc();
1291
1292      return S->getLocStart();
1293    }
1294
1295  return FullSourceLoc();
1296}
1297
1298PathDiagnosticPiece *BugReport::VisitNode(const ExplodedNode *N,
1299                                          const ExplodedNode *PrevN,
1300                                          BugReporterContext &BRC) {
1301  return NULL;
1302}
1303
1304//===----------------------------------------------------------------------===//
1305// Methods for BugReporter and subclasses.
1306//===----------------------------------------------------------------------===//
1307
1308BugReportEquivClass::~BugReportEquivClass() {
1309  for (iterator I=begin(), E=end(); I!=E; ++I) delete *I;
1310}
1311
1312GRBugReporter::~GRBugReporter() { }
1313BugReporterData::~BugReporterData() {}
1314
1315ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); }
1316
1317GRStateManager&
1318GRBugReporter::getStateManager() { return Eng.getStateManager(); }
1319
1320BugReporter::~BugReporter() { FlushReports(); }
1321
1322void BugReporter::FlushReports() {
1323  if (BugTypes.isEmpty())
1324    return;
1325
1326  // First flush the warnings for each BugType.  This may end up creating new
1327  // warnings and new BugTypes.
1328  // FIXME: Only NSErrorChecker needs BugType's FlushReports.
1329  // Turn NSErrorChecker into a proper checker and remove this.
1330  SmallVector<const BugType*, 16> bugTypes;
1331  for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I)
1332    bugTypes.push_back(*I);
1333  for (SmallVector<const BugType*, 16>::iterator
1334         I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I)
1335    const_cast<BugType*>(*I)->FlushReports(*this);
1336
1337  typedef llvm::FoldingSet<BugReportEquivClass> SetTy;
1338  for (SetTy::iterator EI=EQClasses.begin(), EE=EQClasses.end(); EI!=EE;++EI){
1339    BugReportEquivClass& EQ = *EI;
1340    FlushReport(EQ);
1341  }
1342
1343  // BugReporter owns and deletes only BugTypes created implicitly through
1344  // EmitBasicReport.
1345  // FIXME: There are leaks from checkers that assume that the BugTypes they
1346  // create will be destroyed by the BugReporter.
1347  for (llvm::StringMap<BugType*>::iterator
1348         I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I)
1349    delete I->second;
1350
1351  // Remove all references to the BugType objects.
1352  BugTypes = F.getEmptySet();
1353}
1354
1355//===----------------------------------------------------------------------===//
1356// PathDiagnostics generation.
1357//===----------------------------------------------------------------------===//
1358
1359static std::pair<std::pair<ExplodedGraph*, NodeBackMap*>,
1360                 std::pair<ExplodedNode*, unsigned> >
1361MakeReportGraph(const ExplodedGraph* G,
1362                SmallVectorImpl<const ExplodedNode*> &nodes) {
1363
1364  // Create the trimmed graph.  It will contain the shortest paths from the
1365  // error nodes to the root.  In the new graph we should only have one
1366  // error node unless there are two or more error nodes with the same minimum
1367  // path length.
1368  ExplodedGraph* GTrim;
1369  InterExplodedGraphMap* NMap;
1370
1371  llvm::DenseMap<const void*, const void*> InverseMap;
1372  llvm::tie(GTrim, NMap) = G->Trim(nodes.data(), nodes.data() + nodes.size(),
1373                                   &InverseMap);
1374
1375  // Create owning pointers for GTrim and NMap just to ensure that they are
1376  // released when this function exists.
1377  llvm::OwningPtr<ExplodedGraph> AutoReleaseGTrim(GTrim);
1378  llvm::OwningPtr<InterExplodedGraphMap> AutoReleaseNMap(NMap);
1379
1380  // Find the (first) error node in the trimmed graph.  We just need to consult
1381  // the node map (NMap) which maps from nodes in the original graph to nodes
1382  // in the new graph.
1383
1384  std::queue<const ExplodedNode*> WS;
1385  typedef llvm::DenseMap<const ExplodedNode*, unsigned> IndexMapTy;
1386  IndexMapTy IndexMap;
1387
1388  for (unsigned nodeIndex = 0 ; nodeIndex < nodes.size(); ++nodeIndex) {
1389    const ExplodedNode *originalNode = nodes[nodeIndex];
1390    if (const ExplodedNode *N = NMap->getMappedNode(originalNode)) {
1391      WS.push(N);
1392      IndexMap[originalNode] = nodeIndex;
1393    }
1394  }
1395
1396  assert(!WS.empty() && "No error node found in the trimmed graph.");
1397
1398  // Create a new (third!) graph with a single path.  This is the graph
1399  // that will be returned to the caller.
1400  ExplodedGraph *GNew = new ExplodedGraph();
1401
1402  // Sometimes the trimmed graph can contain a cycle.  Perform a reverse BFS
1403  // to the root node, and then construct a new graph that contains only
1404  // a single path.
1405  llvm::DenseMap<const void*,unsigned> Visited;
1406
1407  unsigned cnt = 0;
1408  const ExplodedNode *Root = 0;
1409
1410  while (!WS.empty()) {
1411    const ExplodedNode *Node = WS.front();
1412    WS.pop();
1413
1414    if (Visited.find(Node) != Visited.end())
1415      continue;
1416
1417    Visited[Node] = cnt++;
1418
1419    if (Node->pred_empty()) {
1420      Root = Node;
1421      break;
1422    }
1423
1424    for (ExplodedNode::const_pred_iterator I=Node->pred_begin(),
1425         E=Node->pred_end(); I!=E; ++I)
1426      WS.push(*I);
1427  }
1428
1429  assert(Root);
1430
1431  // Now walk from the root down the BFS path, always taking the successor
1432  // with the lowest number.
1433  ExplodedNode *Last = 0, *First = 0;
1434  NodeBackMap *BM = new NodeBackMap();
1435  unsigned NodeIndex = 0;
1436
1437  for ( const ExplodedNode *N = Root ;;) {
1438    // Lookup the number associated with the current node.
1439    llvm::DenseMap<const void*,unsigned>::iterator I = Visited.find(N);
1440    assert(I != Visited.end());
1441
1442    // Create the equivalent node in the new graph with the same state
1443    // and location.
1444    ExplodedNode *NewN = GNew->getNode(N->getLocation(), N->getState());
1445
1446    // Store the mapping to the original node.
1447    llvm::DenseMap<const void*, const void*>::iterator IMitr=InverseMap.find(N);
1448    assert(IMitr != InverseMap.end() && "No mapping to original node.");
1449    (*BM)[NewN] = (const ExplodedNode*) IMitr->second;
1450
1451    // Link up the new node with the previous node.
1452    if (Last)
1453      NewN->addPredecessor(Last, *GNew);
1454
1455    Last = NewN;
1456
1457    // Are we at the final node?
1458    IndexMapTy::iterator IMI =
1459      IndexMap.find((const ExplodedNode*)(IMitr->second));
1460    if (IMI != IndexMap.end()) {
1461      First = NewN;
1462      NodeIndex = IMI->second;
1463      break;
1464    }
1465
1466    // Find the next successor node.  We choose the node that is marked
1467    // with the lowest DFS number.
1468    ExplodedNode::const_succ_iterator SI = N->succ_begin();
1469    ExplodedNode::const_succ_iterator SE = N->succ_end();
1470    N = 0;
1471
1472    for (unsigned MinVal = 0; SI != SE; ++SI) {
1473
1474      I = Visited.find(*SI);
1475
1476      if (I == Visited.end())
1477        continue;
1478
1479      if (!N || I->second < MinVal) {
1480        N = *SI;
1481        MinVal = I->second;
1482      }
1483    }
1484
1485    assert(N);
1486  }
1487
1488  assert(First);
1489
1490  return std::make_pair(std::make_pair(GNew, BM),
1491                        std::make_pair(First, NodeIndex));
1492}
1493
1494/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object
1495///  and collapses PathDiagosticPieces that are expanded by macros.
1496static void CompactPathDiagnostic(PathDiagnostic &PD, const SourceManager& SM) {
1497  typedef std::vector<std::pair<PathDiagnosticMacroPiece*, SourceLocation> >
1498          MacroStackTy;
1499
1500  typedef std::vector<PathDiagnosticPiece*>
1501          PiecesTy;
1502
1503  MacroStackTy MacroStack;
1504  PiecesTy Pieces;
1505
1506  for (PathDiagnostic::iterator I = PD.begin(), E = PD.end(); I!=E; ++I) {
1507    // Get the location of the PathDiagnosticPiece.
1508    const FullSourceLoc Loc = I->getLocation().asLocation();
1509
1510    // Determine the instantiation location, which is the location we group
1511    // related PathDiagnosticPieces.
1512    SourceLocation InstantiationLoc = Loc.isMacroID() ?
1513                                      SM.getExpansionLoc(Loc) :
1514                                      SourceLocation();
1515
1516    if (Loc.isFileID()) {
1517      MacroStack.clear();
1518      Pieces.push_back(&*I);
1519      continue;
1520    }
1521
1522    assert(Loc.isMacroID());
1523
1524    // Is the PathDiagnosticPiece within the same macro group?
1525    if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) {
1526      MacroStack.back().first->push_back(&*I);
1527      continue;
1528    }
1529
1530    // We aren't in the same group.  Are we descending into a new macro
1531    // or are part of an old one?
1532    PathDiagnosticMacroPiece *MacroGroup = 0;
1533
1534    SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ?
1535                                          SM.getExpansionLoc(Loc) :
1536                                          SourceLocation();
1537
1538    // Walk the entire macro stack.
1539    while (!MacroStack.empty()) {
1540      if (InstantiationLoc == MacroStack.back().second) {
1541        MacroGroup = MacroStack.back().first;
1542        break;
1543      }
1544
1545      if (ParentInstantiationLoc == MacroStack.back().second) {
1546        MacroGroup = MacroStack.back().first;
1547        break;
1548      }
1549
1550      MacroStack.pop_back();
1551    }
1552
1553    if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) {
1554      // Create a new macro group and add it to the stack.
1555      PathDiagnosticMacroPiece *NewGroup = new PathDiagnosticMacroPiece(Loc);
1556
1557      if (MacroGroup)
1558        MacroGroup->push_back(NewGroup);
1559      else {
1560        assert(InstantiationLoc.isFileID());
1561        Pieces.push_back(NewGroup);
1562      }
1563
1564      MacroGroup = NewGroup;
1565      MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc));
1566    }
1567
1568    // Finally, add the PathDiagnosticPiece to the group.
1569    MacroGroup->push_back(&*I);
1570  }
1571
1572  // Now take the pieces and construct a new PathDiagnostic.
1573  PD.resetPath(false);
1574
1575  for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I) {
1576    if (PathDiagnosticMacroPiece *MP=dyn_cast<PathDiagnosticMacroPiece>(*I))
1577      if (!MP->containsEvent()) {
1578        delete MP;
1579        continue;
1580      }
1581
1582    PD.push_back(*I);
1583  }
1584}
1585
1586void GRBugReporter::GeneratePathDiagnostic(PathDiagnostic& PD,
1587                        SmallVectorImpl<BugReport *> &bugReports) {
1588
1589  assert(!bugReports.empty());
1590  SmallVector<const ExplodedNode *, 10> errorNodes;
1591  for (SmallVectorImpl<BugReport*>::iterator I = bugReports.begin(),
1592    E = bugReports.end(); I != E; ++I) {
1593      errorNodes.push_back((*I)->getErrorNode());
1594  }
1595
1596  // Construct a new graph that contains only a single path from the error
1597  // node to a root.
1598  const std::pair<std::pair<ExplodedGraph*, NodeBackMap*>,
1599  std::pair<ExplodedNode*, unsigned> >&
1600    GPair = MakeReportGraph(&getGraph(), errorNodes);
1601
1602  // Find the BugReport with the original location.
1603  assert(GPair.second.second < bugReports.size());
1604  BugReport *R = bugReports[GPair.second.second];
1605  assert(R && "No original report found for sliced graph.");
1606
1607  llvm::OwningPtr<ExplodedGraph> ReportGraph(GPair.first.first);
1608  llvm::OwningPtr<NodeBackMap> BackMap(GPair.first.second);
1609  const ExplodedNode *N = GPair.second.first;
1610
1611  // Start building the path diagnostic...
1612  PathDiagnosticBuilder PDB(*this, R, BackMap.get(), getPathDiagnosticClient());
1613
1614  if (PathDiagnosticPiece *Piece = R->getEndPath(PDB, N))
1615    PD.push_back(Piece);
1616  else
1617    return;
1618
1619  // Register node visitors.
1620  R->registerInitialVisitors(PDB, N);
1621  bugreporter::registerNilReceiverVisitor(PDB);
1622  bugreporter::registerConditionVisitor(PDB);
1623
1624  switch (PDB.getGenerationScheme()) {
1625    case PathDiagnosticClient::Extensive:
1626      GenerateExtensivePathDiagnostic(PD, PDB, N);
1627      break;
1628    case PathDiagnosticClient::Minimal:
1629      GenerateMinimalPathDiagnostic(PD, PDB, N);
1630      break;
1631  }
1632}
1633
1634void BugReporter::Register(BugType *BT) {
1635  BugTypes = F.add(BugTypes, BT);
1636}
1637
1638void BugReporter::EmitReport(BugReport* R) {
1639  // Compute the bug report's hash to determine its equivalence class.
1640  llvm::FoldingSetNodeID ID;
1641  R->Profile(ID);
1642
1643  // Lookup the equivance class.  If there isn't one, create it.
1644  BugType& BT = R->getBugType();
1645  Register(&BT);
1646  void *InsertPos;
1647  BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos);
1648
1649  if (!EQ) {
1650    EQ = new BugReportEquivClass(R);
1651    EQClasses.InsertNode(EQ, InsertPos);
1652  }
1653  else
1654    EQ->AddReport(R);
1655}
1656
1657
1658//===----------------------------------------------------------------------===//
1659// Emitting reports in equivalence classes.
1660//===----------------------------------------------------------------------===//
1661
1662namespace {
1663struct FRIEC_WLItem {
1664  const ExplodedNode *N;
1665  ExplodedNode::const_succ_iterator I, E;
1666
1667  FRIEC_WLItem(const ExplodedNode *n)
1668  : N(n), I(N->succ_begin()), E(N->succ_end()) {}
1669};
1670}
1671
1672static BugReport *
1673FindReportInEquivalenceClass(BugReportEquivClass& EQ,
1674                             SmallVectorImpl<BugReport*> &bugReports) {
1675
1676  BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end();
1677  assert(I != E);
1678  BugReport *R = *I;
1679  BugType& BT = R->getBugType();
1680
1681  // If we don't need to suppress any of the nodes because they are
1682  // post-dominated by a sink, simply add all the nodes in the equivalence class
1683  // to 'Nodes'.  Any of the reports will serve as a "representative" report.
1684  if (!BT.isSuppressOnSink()) {
1685    for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) {
1686      const ExplodedNode *N = I->getErrorNode();
1687      if (N) {
1688        R = *I;
1689        bugReports.push_back(R);
1690      }
1691    }
1692    return R;
1693  }
1694
1695  // For bug reports that should be suppressed when all paths are post-dominated
1696  // by a sink node, iterate through the reports in the equivalence class
1697  // until we find one that isn't post-dominated (if one exists).  We use a
1698  // DFS traversal of the ExplodedGraph to find a non-sink node.  We could write
1699  // this as a recursive function, but we don't want to risk blowing out the
1700  // stack for very long paths.
1701  BugReport *exampleReport = 0;
1702
1703  for (; I != E; ++I) {
1704    R = *I;
1705    const ExplodedNode *errorNode = R->getErrorNode();
1706
1707    if (!errorNode)
1708      continue;
1709    if (errorNode->isSink()) {
1710      assert(false &&
1711           "BugType::isSuppressSink() should not be 'true' for sink end nodes");
1712      return 0;
1713    }
1714    // No successors?  By definition this nodes isn't post-dominated by a sink.
1715    if (errorNode->succ_empty()) {
1716      bugReports.push_back(R);
1717      if (!exampleReport)
1718        exampleReport = R;
1719      continue;
1720    }
1721
1722    // At this point we know that 'N' is not a sink and it has at least one
1723    // successor.  Use a DFS worklist to find a non-sink end-of-path node.
1724    typedef FRIEC_WLItem WLItem;
1725    typedef SmallVector<WLItem, 10> DFSWorkList;
1726    llvm::DenseMap<const ExplodedNode *, unsigned> Visited;
1727
1728    DFSWorkList WL;
1729    WL.push_back(errorNode);
1730    Visited[errorNode] = 1;
1731
1732    while (!WL.empty()) {
1733      WLItem &WI = WL.back();
1734      assert(!WI.N->succ_empty());
1735
1736      for (; WI.I != WI.E; ++WI.I) {
1737        const ExplodedNode *Succ = *WI.I;
1738        // End-of-path node?
1739        if (Succ->succ_empty()) {
1740          // If we found an end-of-path node that is not a sink.
1741          if (!Succ->isSink()) {
1742            bugReports.push_back(R);
1743            if (!exampleReport)
1744              exampleReport = R;
1745            WL.clear();
1746            break;
1747          }
1748          // Found a sink?  Continue on to the next successor.
1749          continue;
1750        }
1751        // Mark the successor as visited.  If it hasn't been explored,
1752        // enqueue it to the DFS worklist.
1753        unsigned &mark = Visited[Succ];
1754        if (!mark) {
1755          mark = 1;
1756          WL.push_back(Succ);
1757          break;
1758        }
1759      }
1760
1761      // The worklist may have been cleared at this point.  First
1762      // check if it is empty before checking the last item.
1763      if (!WL.empty() && &WL.back() == &WI)
1764        WL.pop_back();
1765    }
1766  }
1767
1768  // ExampleReport will be NULL if all the nodes in the equivalence class
1769  // were post-dominated by sinks.
1770  return exampleReport;
1771}
1772
1773//===----------------------------------------------------------------------===//
1774// DiagnosticCache.  This is a hack to cache analyzer diagnostics.  It
1775// uses global state, which eventually should go elsewhere.
1776//===----------------------------------------------------------------------===//
1777namespace {
1778class DiagCacheItem : public llvm::FoldingSetNode {
1779  llvm::FoldingSetNodeID ID;
1780public:
1781  DiagCacheItem(BugReport *R, PathDiagnostic *PD) {
1782    ID.AddString(R->getBugType().getName());
1783    ID.AddString(R->getBugType().getCategory());
1784    ID.AddString(R->getDescription());
1785    ID.AddInteger(R->getLocation().getRawEncoding());
1786    PD->Profile(ID);
1787  }
1788
1789  void Profile(llvm::FoldingSetNodeID &id) {
1790    id = ID;
1791  }
1792
1793  llvm::FoldingSetNodeID &getID() { return ID; }
1794};
1795}
1796
1797static bool IsCachedDiagnostic(BugReport *R, PathDiagnostic *PD) {
1798  // FIXME: Eventually this diagnostic cache should reside in something
1799  // like AnalysisManager instead of being a static variable.  This is
1800  // really unsafe in the long term.
1801  typedef llvm::FoldingSet<DiagCacheItem> DiagnosticCache;
1802  static DiagnosticCache DC;
1803
1804  void *InsertPos;
1805  DiagCacheItem *Item = new DiagCacheItem(R, PD);
1806
1807  if (DC.FindNodeOrInsertPos(Item->getID(), InsertPos)) {
1808    delete Item;
1809    return true;
1810  }
1811
1812  DC.InsertNode(Item, InsertPos);
1813  return false;
1814}
1815
1816void BugReporter::FlushReport(BugReportEquivClass& EQ) {
1817  SmallVector<BugReport*, 10> bugReports;
1818  BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports);
1819  if (!exampleReport)
1820    return;
1821
1822  PathDiagnosticClient* PD = getPathDiagnosticClient();
1823
1824  // FIXME: Make sure we use the 'R' for the path that was actually used.
1825  // Probably doesn't make a difference in practice.
1826  BugType& BT = exampleReport->getBugType();
1827
1828  llvm::OwningPtr<PathDiagnostic>
1829    D(new PathDiagnostic(exampleReport->getBugType().getName(),
1830                         !PD || PD->useVerboseDescription()
1831                         ? exampleReport->getDescription()
1832                         : exampleReport->getShortDescription(),
1833                         BT.getCategory()));
1834
1835  if (!bugReports.empty())
1836    GeneratePathDiagnostic(*D.get(), bugReports);
1837
1838  if (IsCachedDiagnostic(exampleReport, D.get()))
1839    return;
1840
1841  // Get the meta data.
1842  std::pair<const char**, const char**> Meta =
1843    exampleReport->getExtraDescriptiveText();
1844  for (const char** s = Meta.first; s != Meta.second; ++s)
1845    D->addMeta(*s);
1846
1847  // Emit a summary diagnostic to the regular Diagnostics engine.
1848  BugReport::ranges_iterator Beg, End;
1849  llvm::tie(Beg, End) = exampleReport->getRanges();
1850  Diagnostic &Diag = getDiagnostic();
1851  FullSourceLoc L(exampleReport->getLocation(), getSourceManager());
1852
1853  // Search the description for '%', as that will be interpretted as a
1854  // format character by FormatDiagnostics.
1855  StringRef desc = exampleReport->getShortDescription();
1856  unsigned ErrorDiag;
1857  {
1858    llvm::SmallString<512> TmpStr;
1859    llvm::raw_svector_ostream Out(TmpStr);
1860    for (StringRef::iterator I=desc.begin(), E=desc.end(); I!=E; ++I)
1861      if (*I == '%')
1862        Out << "%%";
1863      else
1864        Out << *I;
1865
1866    Out.flush();
1867    ErrorDiag = Diag.getCustomDiagID(Diagnostic::Warning, TmpStr);
1868  }
1869
1870  {
1871    DiagnosticBuilder diagBuilder = Diag.Report(L, ErrorDiag);
1872    for (BugReport::ranges_iterator I = Beg; I != End; ++I)
1873      diagBuilder << *I;
1874  }
1875
1876  // Emit a full diagnostic for the path if we have a PathDiagnosticClient.
1877  if (!PD)
1878    return;
1879
1880  if (D->empty()) {
1881    PathDiagnosticPiece *piece =
1882      new PathDiagnosticEventPiece(L, exampleReport->getDescription());
1883
1884    for ( ; Beg != End; ++Beg) piece->addRange(*Beg);
1885    D->push_back(piece);
1886  }
1887
1888  PD->HandlePathDiagnostic(D.take());
1889}
1890
1891void BugReporter::EmitBasicReport(StringRef name, StringRef str,
1892                                  SourceLocation Loc,
1893                                  SourceRange* RBeg, unsigned NumRanges) {
1894  EmitBasicReport(name, "", str, Loc, RBeg, NumRanges);
1895}
1896
1897void BugReporter::EmitBasicReport(StringRef name,
1898                                  StringRef category,
1899                                  StringRef str, SourceLocation Loc,
1900                                  SourceRange* RBeg, unsigned NumRanges) {
1901
1902  // 'BT' is owned by BugReporter.
1903  BugType *BT = getBugTypeForName(name, category);
1904  FullSourceLoc L = getContext().getFullLoc(Loc);
1905  RangedBugReport *R = new DiagBugReport(*BT, str, L);
1906  for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg);
1907  EmitReport(R);
1908}
1909
1910BugType *BugReporter::getBugTypeForName(StringRef name,
1911                                        StringRef category) {
1912  llvm::SmallString<136> fullDesc;
1913  llvm::raw_svector_ostream(fullDesc) << name << ":" << category;
1914  llvm::StringMapEntry<BugType *> &
1915      entry = StrBugTypes.GetOrCreateValue(fullDesc);
1916  BugType *BT = entry.getValue();
1917  if (!BT) {
1918    BT = new BugType(name, category);
1919    entry.setValue(BT);
1920  }
1921  return BT;
1922}
1923