BugReporter.cpp revision 11abcecc8c919673237cf37384290a1ef1943976 
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/DeclObjC.h"
21#include "clang/AST/Expr.h"
22#include "clang/AST/ParentMap.h"
23#include "clang/AST/StmtObjC.h"
24#include "clang/Basic/SourceManager.h"
25#include "clang/Analysis/ProgramPoint.h"
26#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
27#include "llvm/Support/raw_ostream.h"
28#include "llvm/ADT/DenseMap.h"
29#include "llvm/ADT/SmallString.h"
30#include "llvm/ADT/STLExtras.h"
31#include "llvm/ADT/OwningPtr.h"
32#include "llvm/ADT/IntrusiveRefCntPtr.h"
33#include <queue>
34
35using namespace clang;
36using namespace ento;
37
38BugReporterVisitor::~BugReporterVisitor() {}
39
40void BugReporterContext::anchor() {}
41
42//===----------------------------------------------------------------------===//
43// Helper routines for walking the ExplodedGraph and fetching statements.
44//===----------------------------------------------------------------------===//
45
46static inline const Stmt *GetStmt(const ProgramPoint &P) {
47  if (const StmtPoint* SP = dyn_cast<StmtPoint>(&P))
48    return SP->getStmt();
49  else if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P))
50    return BE->getSrc()->getTerminator();
51
52  return 0;
53}
54
55static inline const ExplodedNode*
56GetPredecessorNode(const ExplodedNode *N) {
57  return N->pred_empty() ? NULL : *(N->pred_begin());
58}
59
60static inline const ExplodedNode*
61GetSuccessorNode(const ExplodedNode *N) {
62  return N->succ_empty() ? NULL : *(N->succ_begin());
63}
64
65static const Stmt *GetPreviousStmt(const ExplodedNode *N) {
66  for (N = GetPredecessorNode(N); N; N = GetPredecessorNode(N))
67    if (const Stmt *S = GetStmt(N->getLocation()))
68      return S;
69
70  return 0;
71}
72
73static const Stmt *GetNextStmt(const ExplodedNode *N) {
74  for (N = GetSuccessorNode(N); N; N = GetSuccessorNode(N))
75    if (const Stmt *S = GetStmt(N->getLocation())) {
76      // Check if the statement is '?' or '&&'/'||'.  These are "merges",
77      // not actual statement points.
78      switch (S->getStmtClass()) {
79        case Stmt::ChooseExprClass:
80        case Stmt::BinaryConditionalOperatorClass: continue;
81        case Stmt::ConditionalOperatorClass: continue;
82        case Stmt::BinaryOperatorClass: {
83          BinaryOperatorKind Op = cast<BinaryOperator>(S)->getOpcode();
84          if (Op == BO_LAnd || Op == BO_LOr)
85            continue;
86          break;
87        }
88        default:
89          break;
90      }
91      return S;
92    }
93
94  return 0;
95}
96
97static inline const Stmt*
98GetCurrentOrPreviousStmt(const ExplodedNode *N) {
99  if (const Stmt *S = GetStmt(N->getLocation()))
100    return S;
101
102  return GetPreviousStmt(N);
103}
104
105static inline const Stmt*
106GetCurrentOrNextStmt(const ExplodedNode *N) {
107  if (const Stmt *S = GetStmt(N->getLocation()))
108    return S;
109
110  return GetNextStmt(N);
111}
112
113//===----------------------------------------------------------------------===//
114// Diagnostic cleanup.
115//===----------------------------------------------------------------------===//
116
117/// Recursively scan through a path and prune out calls and macros pieces
118/// that aren't needed.  Return true if afterwards the path contains
119/// "interesting stuff" which means it should be pruned from the parent path.
120static bool RemoveUneededCalls(PathPieces &pieces) {
121  bool containsSomethingInteresting = false;
122  const unsigned N = pieces.size();
123
124  for (unsigned i = 0 ; i < N ; ++i) {
125    // Remove the front piece from the path.  If it is still something we
126    // want to keep once we are done, we will push it back on the end.
127    IntrusiveRefCntPtr<PathDiagnosticPiece> piece(pieces.front());
128    pieces.pop_front();
129
130    switch (piece->getKind()) {
131      case PathDiagnosticPiece::Call: {
132        PathDiagnosticCallPiece *call = cast<PathDiagnosticCallPiece>(piece);
133        // Recursively clean out the subclass.  Keep this call around if
134        // it contains any informative diagnostics.
135        if (!RemoveUneededCalls(call->path))
136          continue;
137        containsSomethingInteresting = true;
138        break;
139      }
140      case PathDiagnosticPiece::Macro: {
141        PathDiagnosticMacroPiece *macro = cast<PathDiagnosticMacroPiece>(piece);
142        if (!RemoveUneededCalls(macro->subPieces))
143          continue;
144        containsSomethingInteresting = true;
145        break;
146      }
147      case PathDiagnosticPiece::Event: {
148        PathDiagnosticEventPiece *event = cast<PathDiagnosticEventPiece>(piece);
149        // We never throw away an event, but we do throw it away wholesale
150        // as part of a path if we throw the entire path away.
151        if (event->isPrunable())
152          continue;
153        containsSomethingInteresting = true;
154        break;
155      }
156      case PathDiagnosticPiece::ControlFlow:
157        break;
158    }
159
160    pieces.push_back(piece);
161  }
162
163  return containsSomethingInteresting;
164}
165
166//===----------------------------------------------------------------------===//
167// PathDiagnosticBuilder and its associated routines and helper objects.
168//===----------------------------------------------------------------------===//
169
170typedef llvm::DenseMap<const ExplodedNode*,
171const ExplodedNode*> NodeBackMap;
172
173namespace {
174class NodeMapClosure : public BugReport::NodeResolver {
175  NodeBackMap& M;
176public:
177  NodeMapClosure(NodeBackMap *m) : M(*m) {}
178  ~NodeMapClosure() {}
179
180  const ExplodedNode *getOriginalNode(const ExplodedNode *N) {
181    NodeBackMap::iterator I = M.find(N);
182    return I == M.end() ? 0 : I->second;
183  }
184};
185
186class PathDiagnosticBuilder : public BugReporterContext {
187  BugReport *R;
188  PathDiagnosticConsumer *PDC;
189  OwningPtr<ParentMap> PM;
190  NodeMapClosure NMC;
191public:
192  const LocationContext *LC;
193
194  PathDiagnosticBuilder(GRBugReporter &br,
195                        BugReport *r, NodeBackMap *Backmap,
196                        PathDiagnosticConsumer *pdc)
197    : BugReporterContext(br),
198      R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext())
199  {}
200
201  PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N);
202
203  PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os,
204                                            const ExplodedNode *N);
205
206  BugReport *getBugReport() { return R; }
207
208  Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); }
209
210  ParentMap& getParentMap() { return LC->getParentMap(); }
211
212  const Stmt *getParent(const Stmt *S) {
213    return getParentMap().getParent(S);
214  }
215
216  virtual NodeMapClosure& getNodeResolver() { return NMC; }
217
218  PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S);
219
220  PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const {
221    return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive;
222  }
223
224  bool supportsLogicalOpControlFlow() const {
225    return PDC ? PDC->supportsLogicalOpControlFlow() : true;
226  }
227};
228} // end anonymous namespace
229
230PathDiagnosticLocation
231PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) {
232  if (const Stmt *S = GetNextStmt(N))
233    return PathDiagnosticLocation(S, getSourceManager(), LC);
234
235  return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(),
236                                               getSourceManager());
237}
238
239PathDiagnosticLocation
240PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os,
241                                          const ExplodedNode *N) {
242
243  // Slow, but probably doesn't matter.
244  if (os.str().empty())
245    os << ' ';
246
247  const PathDiagnosticLocation &Loc = ExecutionContinues(N);
248
249  if (Loc.asStmt())
250    os << "Execution continues on line "
251       << getSourceManager().getExpansionLineNumber(Loc.asLocation())
252       << '.';
253  else {
254    os << "Execution jumps to the end of the ";
255    const Decl *D = N->getLocationContext()->getDecl();
256    if (isa<ObjCMethodDecl>(D))
257      os << "method";
258    else if (isa<FunctionDecl>(D))
259      os << "function";
260    else {
261      assert(isa<BlockDecl>(D));
262      os << "anonymous block";
263    }
264    os << '.';
265  }
266
267  return Loc;
268}
269
270static bool IsNested(const Stmt *S, ParentMap &PM) {
271  if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S)))
272    return true;
273
274  const Stmt *Parent = PM.getParentIgnoreParens(S);
275
276  if (Parent)
277    switch (Parent->getStmtClass()) {
278      case Stmt::ForStmtClass:
279      case Stmt::DoStmtClass:
280      case Stmt::WhileStmtClass:
281        return true;
282      default:
283        break;
284    }
285
286  return false;
287}
288
289PathDiagnosticLocation
290PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) {
291  assert(S && "Null Stmt *passed to getEnclosingStmtLocation");
292  ParentMap &P = getParentMap();
293  SourceManager &SMgr = getSourceManager();
294
295  while (IsNested(S, P)) {
296    const Stmt *Parent = P.getParentIgnoreParens(S);
297
298    if (!Parent)
299      break;
300
301    switch (Parent->getStmtClass()) {
302      case Stmt::BinaryOperatorClass: {
303        const BinaryOperator *B = cast<BinaryOperator>(Parent);
304        if (B->isLogicalOp())
305          return PathDiagnosticLocation(S, SMgr, LC);
306        break;
307      }
308      case Stmt::CompoundStmtClass:
309      case Stmt::StmtExprClass:
310        return PathDiagnosticLocation(S, SMgr, LC);
311      case Stmt::ChooseExprClass:
312        // Similar to '?' if we are referring to condition, just have the edge
313        // point to the entire choose expression.
314        if (cast<ChooseExpr>(Parent)->getCond() == S)
315          return PathDiagnosticLocation(Parent, SMgr, LC);
316        else
317          return PathDiagnosticLocation(S, SMgr, LC);
318      case Stmt::BinaryConditionalOperatorClass:
319      case Stmt::ConditionalOperatorClass:
320        // For '?', if we are referring to condition, just have the edge point
321        // to the entire '?' expression.
322        if (cast<AbstractConditionalOperator>(Parent)->getCond() == S)
323          return PathDiagnosticLocation(Parent, SMgr, LC);
324        else
325          return PathDiagnosticLocation(S, SMgr, LC);
326      case Stmt::DoStmtClass:
327          return PathDiagnosticLocation(S, SMgr, LC);
328      case Stmt::ForStmtClass:
329        if (cast<ForStmt>(Parent)->getBody() == S)
330          return PathDiagnosticLocation(S, SMgr, LC);
331        break;
332      case Stmt::IfStmtClass:
333        if (cast<IfStmt>(Parent)->getCond() != S)
334          return PathDiagnosticLocation(S, SMgr, LC);
335        break;
336      case Stmt::ObjCForCollectionStmtClass:
337        if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S)
338          return PathDiagnosticLocation(S, SMgr, LC);
339        break;
340      case Stmt::WhileStmtClass:
341        if (cast<WhileStmt>(Parent)->getCond() != S)
342          return PathDiagnosticLocation(S, SMgr, LC);
343        break;
344      default:
345        break;
346    }
347
348    S = Parent;
349  }
350
351  assert(S && "Cannot have null Stmt for PathDiagnosticLocation");
352
353  // Special case: DeclStmts can appear in for statement declarations, in which
354  //  case the ForStmt is the context.
355  if (isa<DeclStmt>(S)) {
356    if (const Stmt *Parent = P.getParent(S)) {
357      switch (Parent->getStmtClass()) {
358        case Stmt::ForStmtClass:
359        case Stmt::ObjCForCollectionStmtClass:
360          return PathDiagnosticLocation(Parent, SMgr, LC);
361        default:
362          break;
363      }
364    }
365  }
366  else if (isa<BinaryOperator>(S)) {
367    // Special case: the binary operator represents the initialization
368    // code in a for statement (this can happen when the variable being
369    // initialized is an old variable.
370    if (const ForStmt *FS =
371          dyn_cast_or_null<ForStmt>(P.getParentIgnoreParens(S))) {
372      if (FS->getInit() == S)
373        return PathDiagnosticLocation(FS, SMgr, LC);
374    }
375  }
376
377  return PathDiagnosticLocation(S, SMgr, LC);
378}
379
380//===----------------------------------------------------------------------===//
381// "Minimal" path diagnostic generation algorithm.
382//===----------------------------------------------------------------------===//
383typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair;
384typedef SmallVector<StackDiagPair, 6> StackDiagVector;
385
386static void updateStackPiecesWithMessage(PathDiagnosticPiece *P,
387                                         StackDiagVector &CallStack) {
388  // If the piece contains a special message, add it to all the call
389  // pieces on the active stack.
390  if (PathDiagnosticEventPiece *ep =
391        dyn_cast<PathDiagnosticEventPiece>(P)) {
392
393    if (ep->hasCallStackHint())
394      for (StackDiagVector::iterator I = CallStack.begin(),
395                                     E = CallStack.end(); I != E; ++I) {
396        PathDiagnosticCallPiece *CP = I->first;
397        const ExplodedNode *N = I->second;
398        std::string stackMsg = ep->getCallStackMessage(N);
399
400        // The last message on the path to final bug is the most important
401        // one. Since we traverse the path backwards, do not add the message
402        // if one has been previously added.
403        if  (!CP->hasCallStackMessage())
404          CP->setCallStackMessage(stackMsg);
405      }
406  }
407}
408
409static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM);
410
411static void GenerateMinimalPathDiagnostic(PathDiagnostic& PD,
412                                          PathDiagnosticBuilder &PDB,
413                                          const ExplodedNode *N,
414                                      ArrayRef<BugReporterVisitor *> visitors) {
415
416  SourceManager& SMgr = PDB.getSourceManager();
417  const LocationContext *LC = PDB.LC;
418  const ExplodedNode *NextNode = N->pred_empty()
419                                        ? NULL : *(N->pred_begin());
420
421  StackDiagVector CallStack;
422
423  while (NextNode) {
424    N = NextNode;
425    PDB.LC = N->getLocationContext();
426    NextNode = GetPredecessorNode(N);
427
428    ProgramPoint P = N->getLocation();
429
430    if (const CallExitEnd *CE = dyn_cast<CallExitEnd>(&P)) {
431      PathDiagnosticCallPiece *C =
432        PathDiagnosticCallPiece::construct(N, *CE, SMgr);
433      PD.getActivePath().push_front(C);
434      PD.pushActivePath(&C->path);
435      CallStack.push_back(StackDiagPair(C, N));
436      continue;
437    }
438
439    if (const CallEnter *CE = dyn_cast<CallEnter>(&P)) {
440      PD.popActivePath();
441      // The current active path should never be empty.  Either we
442      // just added a bunch of stuff to the top-level path, or
443      // we have a previous CallExitEnd.  If the front of the active
444      // path is not a PathDiagnosticCallPiece, it means that the
445      // path terminated within a function call.  We must then take the
446      // current contents of the active path and place it within
447      // a new PathDiagnosticCallPiece.
448      assert(!PD.getActivePath().empty());
449      PathDiagnosticCallPiece *C =
450        dyn_cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
451      if (!C) {
452        const Decl *Caller = CE->getLocationContext()->getDecl();
453        C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
454      }
455      C->setCallee(*CE, SMgr);
456      if (!CallStack.empty()) {
457        assert(CallStack.back().first == C);
458        CallStack.pop_back();
459      }
460      continue;
461    }
462
463    if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
464      const CFGBlock *Src = BE->getSrc();
465      const CFGBlock *Dst = BE->getDst();
466      const Stmt *T = Src->getTerminator();
467
468      if (!T)
469        continue;
470
471      PathDiagnosticLocation Start =
472        PathDiagnosticLocation::createBegin(T, SMgr,
473                                                N->getLocationContext());
474
475      switch (T->getStmtClass()) {
476        default:
477          break;
478
479        case Stmt::GotoStmtClass:
480        case Stmt::IndirectGotoStmtClass: {
481          const Stmt *S = GetNextStmt(N);
482
483          if (!S)
484            continue;
485
486          std::string sbuf;
487          llvm::raw_string_ostream os(sbuf);
488          const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S);
489
490          os << "Control jumps to line "
491          << End.asLocation().getExpansionLineNumber();
492          PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
493                                                                os.str()));
494          break;
495        }
496
497        case Stmt::SwitchStmtClass: {
498          // Figure out what case arm we took.
499          std::string sbuf;
500          llvm::raw_string_ostream os(sbuf);
501
502          if (const Stmt *S = Dst->getLabel()) {
503            PathDiagnosticLocation End(S, SMgr, LC);
504
505            switch (S->getStmtClass()) {
506              default:
507                os << "No cases match in the switch statement. "
508                "Control jumps to line "
509                << End.asLocation().getExpansionLineNumber();
510                break;
511              case Stmt::DefaultStmtClass:
512                os << "Control jumps to the 'default' case at line "
513                << End.asLocation().getExpansionLineNumber();
514                break;
515
516              case Stmt::CaseStmtClass: {
517                os << "Control jumps to 'case ";
518                const CaseStmt *Case = cast<CaseStmt>(S);
519                const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
520
521                // Determine if it is an enum.
522                bool GetRawInt = true;
523
524                if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) {
525                  // FIXME: Maybe this should be an assertion.  Are there cases
526                  // were it is not an EnumConstantDecl?
527                  const EnumConstantDecl *D =
528                    dyn_cast<EnumConstantDecl>(DR->getDecl());
529
530                  if (D) {
531                    GetRawInt = false;
532                    os << *D;
533                  }
534                }
535
536                if (GetRawInt)
537                  os << LHS->EvaluateKnownConstInt(PDB.getASTContext());
538
539                os << ":'  at line "
540                << End.asLocation().getExpansionLineNumber();
541                break;
542              }
543            }
544            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
545                                                             os.str()));
546          }
547          else {
548            os << "'Default' branch taken. ";
549            const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N);
550            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
551                                                             os.str()));
552          }
553
554          break;
555        }
556
557        case Stmt::BreakStmtClass:
558        case Stmt::ContinueStmtClass: {
559          std::string sbuf;
560          llvm::raw_string_ostream os(sbuf);
561          PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
562          PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
563                                                           os.str()));
564          break;
565        }
566
567          // Determine control-flow for ternary '?'.
568        case Stmt::BinaryConditionalOperatorClass:
569        case Stmt::ConditionalOperatorClass: {
570          std::string sbuf;
571          llvm::raw_string_ostream os(sbuf);
572          os << "'?' condition is ";
573
574          if (*(Src->succ_begin()+1) == Dst)
575            os << "false";
576          else
577            os << "true";
578
579          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
580
581          if (const Stmt *S = End.asStmt())
582            End = PDB.getEnclosingStmtLocation(S);
583
584          PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
585                                                           os.str()));
586          break;
587        }
588
589          // Determine control-flow for short-circuited '&&' and '||'.
590        case Stmt::BinaryOperatorClass: {
591          if (!PDB.supportsLogicalOpControlFlow())
592            break;
593
594          const BinaryOperator *B = cast<BinaryOperator>(T);
595          std::string sbuf;
596          llvm::raw_string_ostream os(sbuf);
597          os << "Left side of '";
598
599          if (B->getOpcode() == BO_LAnd) {
600            os << "&&" << "' is ";
601
602            if (*(Src->succ_begin()+1) == Dst) {
603              os << "false";
604              PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
605              PathDiagnosticLocation Start =
606                PathDiagnosticLocation::createOperatorLoc(B, SMgr);
607              PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
608                                                               os.str()));
609            }
610            else {
611              os << "true";
612              PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
613              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
614              PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
615                                                               os.str()));
616            }
617          }
618          else {
619            assert(B->getOpcode() == BO_LOr);
620            os << "||" << "' is ";
621
622            if (*(Src->succ_begin()+1) == Dst) {
623              os << "false";
624              PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
625              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
626              PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
627                                                               os.str()));
628            }
629            else {
630              os << "true";
631              PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
632              PathDiagnosticLocation Start =
633                PathDiagnosticLocation::createOperatorLoc(B, SMgr);
634              PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
635                                                               os.str()));
636            }
637          }
638
639          break;
640        }
641
642        case Stmt::DoStmtClass:  {
643          if (*(Src->succ_begin()) == Dst) {
644            std::string sbuf;
645            llvm::raw_string_ostream os(sbuf);
646
647            os << "Loop condition is true. ";
648            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
649
650            if (const Stmt *S = End.asStmt())
651              End = PDB.getEnclosingStmtLocation(S);
652
653            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
654                                                             os.str()));
655          }
656          else {
657            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
658
659            if (const Stmt *S = End.asStmt())
660              End = PDB.getEnclosingStmtLocation(S);
661
662            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
663                              "Loop condition is false.  Exiting loop"));
664          }
665
666          break;
667        }
668
669        case Stmt::WhileStmtClass:
670        case Stmt::ForStmtClass: {
671          if (*(Src->succ_begin()+1) == Dst) {
672            std::string sbuf;
673            llvm::raw_string_ostream os(sbuf);
674
675            os << "Loop condition is false. ";
676            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
677            if (const Stmt *S = End.asStmt())
678              End = PDB.getEnclosingStmtLocation(S);
679
680            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
681                                                             os.str()));
682          }
683          else {
684            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
685            if (const Stmt *S = End.asStmt())
686              End = PDB.getEnclosingStmtLocation(S);
687
688            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
689                            "Loop condition is true.  Entering loop body"));
690          }
691
692          break;
693        }
694
695        case Stmt::IfStmtClass: {
696          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
697
698          if (const Stmt *S = End.asStmt())
699            End = PDB.getEnclosingStmtLocation(S);
700
701          if (*(Src->succ_begin()+1) == Dst)
702            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
703                                                        "Taking false branch"));
704          else
705            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(Start, End,
706                                                         "Taking true branch"));
707
708          break;
709        }
710      }
711    }
712
713    if (NextNode) {
714      // Add diagnostic pieces from custom visitors.
715      BugReport *R = PDB.getBugReport();
716      for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(),
717                                                    E = visitors.end();
718           I != E; ++I) {
719        if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) {
720          PD.getActivePath().push_front(p);
721          updateStackPiecesWithMessage(p, CallStack);
722        }
723      }
724    }
725  }
726
727  // After constructing the full PathDiagnostic, do a pass over it to compact
728  // PathDiagnosticPieces that occur within a macro.
729  CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager());
730}
731
732//===----------------------------------------------------------------------===//
733// "Extensive" PathDiagnostic generation.
734//===----------------------------------------------------------------------===//
735
736static bool IsControlFlowExpr(const Stmt *S) {
737  const Expr *E = dyn_cast<Expr>(S);
738
739  if (!E)
740    return false;
741
742  E = E->IgnoreParenCasts();
743
744  if (isa<AbstractConditionalOperator>(E))
745    return true;
746
747  if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E))
748    if (B->isLogicalOp())
749      return true;
750
751  return false;
752}
753
754namespace {
755class ContextLocation : public PathDiagnosticLocation {
756  bool IsDead;
757public:
758  ContextLocation(const PathDiagnosticLocation &L, bool isdead = false)
759    : PathDiagnosticLocation(L), IsDead(isdead) {}
760
761  void markDead() { IsDead = true; }
762  bool isDead() const { return IsDead; }
763};
764
765class EdgeBuilder {
766  std::vector<ContextLocation> CLocs;
767  typedef std::vector<ContextLocation>::iterator iterator;
768  PathDiagnostic &PD;
769  PathDiagnosticBuilder &PDB;
770  PathDiagnosticLocation PrevLoc;
771
772  bool IsConsumedExpr(const PathDiagnosticLocation &L);
773
774  bool containsLocation(const PathDiagnosticLocation &Container,
775                        const PathDiagnosticLocation &Containee);
776
777  PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L);
778
779  PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L,
780                                         bool firstCharOnly = false) {
781    if (const Stmt *S = L.asStmt()) {
782      const Stmt *Original = S;
783      while (1) {
784        // Adjust the location for some expressions that are best referenced
785        // by one of their subexpressions.
786        switch (S->getStmtClass()) {
787          default:
788            break;
789          case Stmt::ParenExprClass:
790          case Stmt::GenericSelectionExprClass:
791            S = cast<Expr>(S)->IgnoreParens();
792            firstCharOnly = true;
793            continue;
794          case Stmt::BinaryConditionalOperatorClass:
795          case Stmt::ConditionalOperatorClass:
796            S = cast<AbstractConditionalOperator>(S)->getCond();
797            firstCharOnly = true;
798            continue;
799          case Stmt::ChooseExprClass:
800            S = cast<ChooseExpr>(S)->getCond();
801            firstCharOnly = true;
802            continue;
803          case Stmt::BinaryOperatorClass:
804            S = cast<BinaryOperator>(S)->getLHS();
805            firstCharOnly = true;
806            continue;
807        }
808
809        break;
810      }
811
812      if (S != Original)
813        L = PathDiagnosticLocation(S, L.getManager(), PDB.LC);
814    }
815
816    if (firstCharOnly)
817      L  = PathDiagnosticLocation::createSingleLocation(L);
818
819    return L;
820  }
821
822  void popLocation() {
823    if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) {
824      // For contexts, we only one the first character as the range.
825      rawAddEdge(cleanUpLocation(CLocs.back(), true));
826    }
827    CLocs.pop_back();
828  }
829
830public:
831  EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb)
832    : PD(pd), PDB(pdb) {
833
834      // If the PathDiagnostic already has pieces, add the enclosing statement
835      // of the first piece as a context as well.
836      if (!PD.path.empty()) {
837        PrevLoc = (*PD.path.begin())->getLocation();
838
839        if (const Stmt *S = PrevLoc.asStmt())
840          addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
841      }
842  }
843
844  ~EdgeBuilder() {
845    while (!CLocs.empty()) popLocation();
846
847    // Finally, add an initial edge from the start location of the first
848    // statement (if it doesn't already exist).
849    PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin(
850                                                       PDB.LC,
851                                                       PDB.getSourceManager());
852    if (L.isValid())
853      rawAddEdge(L);
854  }
855
856  void flushLocations() {
857    while (!CLocs.empty())
858      popLocation();
859    PrevLoc = PathDiagnosticLocation();
860  }
861
862  void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false);
863
864  void rawAddEdge(PathDiagnosticLocation NewLoc);
865
866  void addContext(const Stmt *S);
867  void addExtendedContext(const Stmt *S);
868};
869} // end anonymous namespace
870
871
872PathDiagnosticLocation
873EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) {
874  if (const Stmt *S = L.asStmt()) {
875    if (IsControlFlowExpr(S))
876      return L;
877
878    return PDB.getEnclosingStmtLocation(S);
879  }
880
881  return L;
882}
883
884bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container,
885                                   const PathDiagnosticLocation &Containee) {
886
887  if (Container == Containee)
888    return true;
889
890  if (Container.asDecl())
891    return true;
892
893  if (const Stmt *S = Containee.asStmt())
894    if (const Stmt *ContainerS = Container.asStmt()) {
895      while (S) {
896        if (S == ContainerS)
897          return true;
898        S = PDB.getParent(S);
899      }
900      return false;
901    }
902
903  // Less accurate: compare using source ranges.
904  SourceRange ContainerR = Container.asRange();
905  SourceRange ContaineeR = Containee.asRange();
906
907  SourceManager &SM = PDB.getSourceManager();
908  SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin());
909  SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd());
910  SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin());
911  SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd());
912
913  unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg);
914  unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd);
915  unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg);
916  unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd);
917
918  assert(ContainerBegLine <= ContainerEndLine);
919  assert(ContaineeBegLine <= ContaineeEndLine);
920
921  return (ContainerBegLine <= ContaineeBegLine &&
922          ContainerEndLine >= ContaineeEndLine &&
923          (ContainerBegLine != ContaineeBegLine ||
924           SM.getExpansionColumnNumber(ContainerRBeg) <=
925           SM.getExpansionColumnNumber(ContaineeRBeg)) &&
926          (ContainerEndLine != ContaineeEndLine ||
927           SM.getExpansionColumnNumber(ContainerREnd) >=
928           SM.getExpansionColumnNumber(ContaineeREnd)));
929}
930
931void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) {
932  if (!PrevLoc.isValid()) {
933    PrevLoc = NewLoc;
934    return;
935  }
936
937  const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc);
938  const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc);
939
940  if (NewLocClean.asLocation() == PrevLocClean.asLocation())
941    return;
942
943  // FIXME: Ignore intra-macro edges for now.
944  if (NewLocClean.asLocation().getExpansionLoc() ==
945      PrevLocClean.asLocation().getExpansionLoc())
946    return;
947
948  PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean));
949  PrevLoc = NewLoc;
950}
951
952void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd) {
953
954  if (!alwaysAdd && NewLoc.asLocation().isMacroID())
955    return;
956
957  const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc);
958
959  while (!CLocs.empty()) {
960    ContextLocation &TopContextLoc = CLocs.back();
961
962    // Is the top location context the same as the one for the new location?
963    if (TopContextLoc == CLoc) {
964      if (alwaysAdd) {
965        if (IsConsumedExpr(TopContextLoc) &&
966            !IsControlFlowExpr(TopContextLoc.asStmt()))
967            TopContextLoc.markDead();
968
969        rawAddEdge(NewLoc);
970      }
971
972      return;
973    }
974
975    if (containsLocation(TopContextLoc, CLoc)) {
976      if (alwaysAdd) {
977        rawAddEdge(NewLoc);
978
979        if (IsConsumedExpr(CLoc) && !IsControlFlowExpr(CLoc.asStmt())) {
980          CLocs.push_back(ContextLocation(CLoc, true));
981          return;
982        }
983      }
984
985      CLocs.push_back(CLoc);
986      return;
987    }
988
989    // Context does not contain the location.  Flush it.
990    popLocation();
991  }
992
993  // If we reach here, there is no enclosing context.  Just add the edge.
994  rawAddEdge(NewLoc);
995}
996
997bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) {
998  if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt()))
999    return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X);
1000
1001  return false;
1002}
1003
1004void EdgeBuilder::addExtendedContext(const Stmt *S) {
1005  if (!S)
1006    return;
1007
1008  const Stmt *Parent = PDB.getParent(S);
1009  while (Parent) {
1010    if (isa<CompoundStmt>(Parent))
1011      Parent = PDB.getParent(Parent);
1012    else
1013      break;
1014  }
1015
1016  if (Parent) {
1017    switch (Parent->getStmtClass()) {
1018      case Stmt::DoStmtClass:
1019      case Stmt::ObjCAtSynchronizedStmtClass:
1020        addContext(Parent);
1021      default:
1022        break;
1023    }
1024  }
1025
1026  addContext(S);
1027}
1028
1029void EdgeBuilder::addContext(const Stmt *S) {
1030  if (!S)
1031    return;
1032
1033  PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC);
1034
1035  while (!CLocs.empty()) {
1036    const PathDiagnosticLocation &TopContextLoc = CLocs.back();
1037
1038    // Is the top location context the same as the one for the new location?
1039    if (TopContextLoc == L)
1040      return;
1041
1042    if (containsLocation(TopContextLoc, L)) {
1043      CLocs.push_back(L);
1044      return;
1045    }
1046
1047    // Context does not contain the location.  Flush it.
1048    popLocation();
1049  }
1050
1051  CLocs.push_back(L);
1052}
1053
1054// Cone-of-influence: support the reverse propagation of "interesting" symbols
1055// and values by tracing interesting calculations backwards through evaluated
1056// expressions along a path.  This is probably overly complicated, but the idea
1057// is that if an expression computed an "interesting" value, the child
1058// expressions are are also likely to be "interesting" as well (which then
1059// propagates to the values they in turn compute).  This reverse propagation
1060// is needed to track interesting correlations across function call boundaries,
1061// where formal arguments bind to actual arguments, etc.  This is also needed
1062// because the constraint solver sometimes simplifies certain symbolic values
1063// into constants when appropriate, and this complicates reasoning about
1064// interesting values.
1065typedef llvm::DenseSet<const Expr *> InterestingExprs;
1066
1067static void reversePropagateIntererstingSymbols(BugReport &R,
1068                                                InterestingExprs &IE,
1069                                                const ProgramState *State,
1070                                                const Expr *Ex,
1071                                                const LocationContext *LCtx) {
1072  SVal V = State->getSVal(Ex, LCtx);
1073  if (!(R.isInteresting(V) || IE.count(Ex)))
1074    return;
1075
1076  switch (Ex->getStmtClass()) {
1077    default:
1078      if (!isa<CastExpr>(Ex))
1079        break;
1080      // Fall through.
1081    case Stmt::BinaryOperatorClass:
1082    case Stmt::UnaryOperatorClass: {
1083      for (Stmt::const_child_iterator CI = Ex->child_begin(),
1084            CE = Ex->child_end();
1085            CI != CE; ++CI) {
1086        if (const Expr *child = dyn_cast_or_null<Expr>(*CI)) {
1087          IE.insert(child);
1088          SVal ChildV = State->getSVal(child, LCtx);
1089          R.markInteresting(ChildV);
1090        }
1091        break;
1092      }
1093    }
1094  }
1095
1096  R.markInteresting(V);
1097}
1098
1099static void reversePropagateInterestingSymbols(BugReport &R,
1100                                               InterestingExprs &IE,
1101                                               const ProgramState *State,
1102                                               const LocationContext *CalleeCtx,
1103                                               const LocationContext *CallerCtx)
1104{
1105  // FIXME: Handle CXXConstructExpr.
1106  // FIXME: Handle calls to blocks.
1107  const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame();
1108  const Stmt *CallSite = Callee->getCallSite();
1109  if (const CallExpr *CE = dyn_cast<CallExpr>(CallSite)) {
1110    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) {
1111      FunctionDecl::param_const_iterator PI = FD->param_begin(),
1112                                         PE = FD->param_end();
1113      CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end();
1114      for (; AI != AE && PI != PE; ++AI, ++PI) {
1115        if (const Expr *ArgE = *AI) {
1116          if (const ParmVarDecl *PD = *PI) {
1117            Loc LV = State->getLValue(PD, CalleeCtx);
1118            if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV)))
1119              IE.insert(ArgE);
1120          }
1121        }
1122      }
1123    }
1124  }
1125}
1126
1127static void GenerateExtensivePathDiagnostic(PathDiagnostic& PD,
1128                                            PathDiagnosticBuilder &PDB,
1129                                            const ExplodedNode *N,
1130                                      ArrayRef<BugReporterVisitor *> visitors) {
1131  EdgeBuilder EB(PD, PDB);
1132  const SourceManager& SM = PDB.getSourceManager();
1133  StackDiagVector CallStack;
1134  InterestingExprs IE;
1135
1136  const ExplodedNode *NextNode = N->pred_empty() ? NULL : *(N->pred_begin());
1137  while (NextNode) {
1138    N = NextNode;
1139    NextNode = GetPredecessorNode(N);
1140    ProgramPoint P = N->getLocation();
1141
1142    do {
1143      if (const PostStmt *PS = dyn_cast<PostStmt>(&P)) {
1144        if (const Expr *Ex = PS->getStmtAs<Expr>())
1145          reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1146                                              N->getState().getPtr(), Ex,
1147                                              N->getLocationContext());
1148      }
1149
1150      if (const CallExitEnd *CE = dyn_cast<CallExitEnd>(&P)) {
1151        const StackFrameContext *LCtx =
1152        CE->getLocationContext()->getCurrentStackFrame();
1153        PathDiagnosticLocation Loc(CE->getStmt(),
1154                                   PDB.getSourceManager(),
1155                                   LCtx);
1156        EB.addEdge(Loc, true);
1157        EB.flushLocations();
1158        PathDiagnosticCallPiece *C =
1159          PathDiagnosticCallPiece::construct(N, *CE, SM);
1160        PD.getActivePath().push_front(C);
1161        PD.pushActivePath(&C->path);
1162        CallStack.push_back(StackDiagPair(C, N));
1163        break;
1164      }
1165
1166      // Pop the call hierarchy if we are done walking the contents
1167      // of a function call.
1168      if (const CallEnter *CE = dyn_cast<CallEnter>(&P)) {
1169        // Add an edge to the start of the function.
1170        const Decl *D = CE->getCalleeContext()->getDecl();
1171        PathDiagnosticLocation pos =
1172          PathDiagnosticLocation::createBegin(D, SM);
1173        EB.addEdge(pos);
1174
1175        // Flush all locations, and pop the active path.
1176        EB.flushLocations();
1177        PD.popActivePath();
1178        assert(!PD.getActivePath().empty());
1179        PDB.LC = N->getLocationContext();
1180
1181        // The current active path should never be empty.  Either we
1182        // just added a bunch of stuff to the top-level path, or
1183        // we have a previous CallExitEnd.  If the front of the active
1184        // path is not a PathDiagnosticCallPiece, it means that the
1185        // path terminated within a function call.  We must then take the
1186        // current contents of the active path and place it within
1187        // a new PathDiagnosticCallPiece.
1188        PathDiagnosticCallPiece *C =
1189          dyn_cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
1190        if (!C) {
1191          const Decl * Caller = CE->getLocationContext()->getDecl();
1192          C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
1193        }
1194        C->setCallee(*CE, SM);
1195        EB.addContext(CE->getCallExpr());
1196
1197        if (!CallStack.empty()) {
1198          assert(CallStack.back().first == C);
1199          CallStack.pop_back();
1200        }
1201        break;
1202      }
1203
1204      // Note that is important that we update the LocationContext
1205      // after looking at CallExits.  CallExit basically adds an
1206      // edge in the *caller*, so we don't want to update the LocationContext
1207      // too soon.
1208      PDB.LC = N->getLocationContext();
1209
1210      // Block edges.
1211      if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
1212        // Does this represent entering a call?  If so, look at propagating
1213        // interesting symbols across call boundaries.
1214        if (NextNode) {
1215          const LocationContext *CallerCtx = NextNode->getLocationContext();
1216          const LocationContext *CalleeCtx = PDB.LC;
1217          if (CallerCtx != CalleeCtx) {
1218            reversePropagateInterestingSymbols(*PDB.getBugReport(), IE,
1219                                               N->getState().getPtr(),
1220                                               CalleeCtx, CallerCtx);
1221          }
1222        }
1223
1224        const CFGBlock &Blk = *BE->getSrc();
1225        const Stmt *Term = Blk.getTerminator();
1226
1227        // Are we jumping to the head of a loop?  Add a special diagnostic.
1228        if (const Stmt *Loop = BE->getDst()->getLoopTarget()) {
1229          PathDiagnosticLocation L(Loop, SM, PDB.LC);
1230          const CompoundStmt *CS = NULL;
1231
1232          if (!Term) {
1233            if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
1234              CS = dyn_cast<CompoundStmt>(FS->getBody());
1235            else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
1236              CS = dyn_cast<CompoundStmt>(WS->getBody());
1237          }
1238
1239          PathDiagnosticEventPiece *p =
1240            new PathDiagnosticEventPiece(L,
1241                                        "Looping back to the head of the loop");
1242          p->setPrunable(true);
1243
1244          EB.addEdge(p->getLocation(), true);
1245          PD.getActivePath().push_front(p);
1246
1247          if (CS) {
1248            PathDiagnosticLocation BL =
1249              PathDiagnosticLocation::createEndBrace(CS, SM);
1250            EB.addEdge(BL);
1251          }
1252        }
1253
1254        if (Term)
1255          EB.addContext(Term);
1256
1257        break;
1258      }
1259
1260      if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
1261        if (const CFGStmt *S = BE->getFirstElement().getAs<CFGStmt>()) {
1262          const Stmt *stmt = S->getStmt();
1263          if (IsControlFlowExpr(stmt)) {
1264            // Add the proper context for '&&', '||', and '?'.
1265            EB.addContext(stmt);
1266          }
1267          else
1268            EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt());
1269        }
1270
1271        break;
1272      }
1273
1274
1275    } while (0);
1276
1277    if (!NextNode)
1278      continue;
1279
1280    // Add pieces from custom visitors.
1281    BugReport *R = PDB.getBugReport();
1282    for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(),
1283                                                  E = visitors.end();
1284         I != E; ++I) {
1285      if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) {
1286        const PathDiagnosticLocation &Loc = p->getLocation();
1287        EB.addEdge(Loc, true);
1288        PD.getActivePath().push_front(p);
1289        updateStackPiecesWithMessage(p, CallStack);
1290
1291        if (const Stmt *S = Loc.asStmt())
1292          EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
1293      }
1294    }
1295  }
1296}
1297
1298//===----------------------------------------------------------------------===//
1299// Methods for BugType and subclasses.
1300//===----------------------------------------------------------------------===//
1301BugType::~BugType() { }
1302
1303void BugType::FlushReports(BugReporter &BR) {}
1304
1305void BuiltinBug::anchor() {}
1306
1307//===----------------------------------------------------------------------===//
1308// Methods for BugReport and subclasses.
1309//===----------------------------------------------------------------------===//
1310
1311void BugReport::NodeResolver::anchor() {}
1312
1313void BugReport::addVisitor(BugReporterVisitor* visitor) {
1314  if (!visitor)
1315    return;
1316
1317  llvm::FoldingSetNodeID ID;
1318  visitor->Profile(ID);
1319  void *InsertPos;
1320
1321  if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) {
1322    delete visitor;
1323    return;
1324  }
1325
1326  CallbacksSet.InsertNode(visitor, InsertPos);
1327  Callbacks.push_back(visitor);
1328  ++ConfigurationChangeToken;
1329}
1330
1331BugReport::~BugReport() {
1332  for (visitor_iterator I = visitor_begin(), E = visitor_end(); I != E; ++I) {
1333    delete *I;
1334  }
1335}
1336
1337const Decl *BugReport::getDeclWithIssue() const {
1338  if (DeclWithIssue)
1339    return DeclWithIssue;
1340
1341  const ExplodedNode *N = getErrorNode();
1342  if (!N)
1343    return 0;
1344
1345  const LocationContext *LC = N->getLocationContext();
1346  return LC->getCurrentStackFrame()->getDecl();
1347}
1348
1349void BugReport::Profile(llvm::FoldingSetNodeID& hash) const {
1350  hash.AddPointer(&BT);
1351  hash.AddString(Description);
1352  if (UniqueingLocation.isValid()) {
1353    UniqueingLocation.Profile(hash);
1354  } else if (Location.isValid()) {
1355    Location.Profile(hash);
1356  } else {
1357    assert(ErrorNode);
1358    hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode));
1359  }
1360
1361  for (SmallVectorImpl<SourceRange>::const_iterator I =
1362      Ranges.begin(), E = Ranges.end(); I != E; ++I) {
1363    const SourceRange range = *I;
1364    if (!range.isValid())
1365      continue;
1366    hash.AddInteger(range.getBegin().getRawEncoding());
1367    hash.AddInteger(range.getEnd().getRawEncoding());
1368  }
1369}
1370
1371void BugReport::markInteresting(SymbolRef sym) {
1372  if (!sym)
1373    return;
1374
1375  // If the symbol wasn't already in our set, note a configuration change.
1376  if (interestingSymbols.insert(sym).second)
1377    ++ConfigurationChangeToken;
1378
1379  if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym))
1380    interestingRegions.insert(meta->getRegion());
1381}
1382
1383void BugReport::markInteresting(const MemRegion *R) {
1384  if (!R)
1385    return;
1386
1387  // If the base region wasn't already in our set, note a configuration change.
1388  R = R->getBaseRegion();
1389  if (interestingRegions.insert(R).second)
1390    ++ConfigurationChangeToken;
1391
1392  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1393    interestingSymbols.insert(SR->getSymbol());
1394}
1395
1396void BugReport::markInteresting(SVal V) {
1397  markInteresting(V.getAsRegion());
1398  markInteresting(V.getAsSymbol());
1399}
1400
1401bool BugReport::isInteresting(SVal V) const {
1402  return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol());
1403}
1404
1405bool BugReport::isInteresting(SymbolRef sym) const {
1406  if (!sym)
1407    return false;
1408  // We don't currently consider metadata symbols to be interesting
1409  // even if we know their region is interesting. Is that correct behavior?
1410  return interestingSymbols.count(sym);
1411}
1412
1413bool BugReport::isInteresting(const MemRegion *R) const {
1414  if (!R)
1415    return false;
1416  R = R->getBaseRegion();
1417  bool b = interestingRegions.count(R);
1418  if (b)
1419    return true;
1420  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1421    return interestingSymbols.count(SR->getSymbol());
1422  return false;
1423}
1424
1425
1426const Stmt *BugReport::getStmt() const {
1427  if (!ErrorNode)
1428    return 0;
1429
1430  ProgramPoint ProgP = ErrorNode->getLocation();
1431  const Stmt *S = NULL;
1432
1433  if (BlockEntrance *BE = dyn_cast<BlockEntrance>(&ProgP)) {
1434    CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit();
1435    if (BE->getBlock() == &Exit)
1436      S = GetPreviousStmt(ErrorNode);
1437  }
1438  if (!S)
1439    S = GetStmt(ProgP);
1440
1441  return S;
1442}
1443
1444std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator>
1445BugReport::getRanges() {
1446    // If no custom ranges, add the range of the statement corresponding to
1447    // the error node.
1448    if (Ranges.empty()) {
1449      if (const Expr *E = dyn_cast_or_null<Expr>(getStmt()))
1450        addRange(E->getSourceRange());
1451      else
1452        return std::make_pair(ranges_iterator(), ranges_iterator());
1453    }
1454
1455    // User-specified absence of range info.
1456    if (Ranges.size() == 1 && !Ranges.begin()->isValid())
1457      return std::make_pair(ranges_iterator(), ranges_iterator());
1458
1459    return std::make_pair(Ranges.begin(), Ranges.end());
1460}
1461
1462PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const {
1463  if (ErrorNode) {
1464    assert(!Location.isValid() &&
1465     "Either Location or ErrorNode should be specified but not both.");
1466
1467    if (const Stmt *S = GetCurrentOrPreviousStmt(ErrorNode)) {
1468      const LocationContext *LC = ErrorNode->getLocationContext();
1469
1470      // For member expressions, return the location of the '.' or '->'.
1471      if (const MemberExpr *ME = dyn_cast<MemberExpr>(S))
1472        return PathDiagnosticLocation::createMemberLoc(ME, SM);
1473      // For binary operators, return the location of the operator.
1474      if (const BinaryOperator *B = dyn_cast<BinaryOperator>(S))
1475        return PathDiagnosticLocation::createOperatorLoc(B, SM);
1476
1477      return PathDiagnosticLocation::createBegin(S, SM, LC);
1478    }
1479  } else {
1480    assert(Location.isValid());
1481    return Location;
1482  }
1483
1484  return PathDiagnosticLocation();
1485}
1486
1487//===----------------------------------------------------------------------===//
1488// Methods for BugReporter and subclasses.
1489//===----------------------------------------------------------------------===//
1490
1491BugReportEquivClass::~BugReportEquivClass() { }
1492GRBugReporter::~GRBugReporter() { }
1493BugReporterData::~BugReporterData() {}
1494
1495ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); }
1496
1497ProgramStateManager&
1498GRBugReporter::getStateManager() { return Eng.getStateManager(); }
1499
1500BugReporter::~BugReporter() {
1501  FlushReports();
1502
1503  // Free the bug reports we are tracking.
1504  typedef std::vector<BugReportEquivClass *> ContTy;
1505  for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end();
1506       I != E; ++I) {
1507    delete *I;
1508  }
1509}
1510
1511void BugReporter::FlushReports() {
1512  if (BugTypes.isEmpty())
1513    return;
1514
1515  // First flush the warnings for each BugType.  This may end up creating new
1516  // warnings and new BugTypes.
1517  // FIXME: Only NSErrorChecker needs BugType's FlushReports.
1518  // Turn NSErrorChecker into a proper checker and remove this.
1519  SmallVector<const BugType*, 16> bugTypes;
1520  for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I)
1521    bugTypes.push_back(*I);
1522  for (SmallVector<const BugType*, 16>::iterator
1523         I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I)
1524    const_cast<BugType*>(*I)->FlushReports(*this);
1525
1526  typedef llvm::FoldingSet<BugReportEquivClass> SetTy;
1527  for (SetTy::iterator EI=EQClasses.begin(), EE=EQClasses.end(); EI!=EE;++EI){
1528    BugReportEquivClass& EQ = *EI;
1529    FlushReport(EQ);
1530  }
1531
1532  // BugReporter owns and deletes only BugTypes created implicitly through
1533  // EmitBasicReport.
1534  // FIXME: There are leaks from checkers that assume that the BugTypes they
1535  // create will be destroyed by the BugReporter.
1536  for (llvm::StringMap<BugType*>::iterator
1537         I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I)
1538    delete I->second;
1539
1540  // Remove all references to the BugType objects.
1541  BugTypes = F.getEmptySet();
1542}
1543
1544//===----------------------------------------------------------------------===//
1545// PathDiagnostics generation.
1546//===----------------------------------------------------------------------===//
1547
1548static std::pair<std::pair<ExplodedGraph*, NodeBackMap*>,
1549                 std::pair<ExplodedNode*, unsigned> >
1550MakeReportGraph(const ExplodedGraph* G,
1551                SmallVectorImpl<const ExplodedNode*> &nodes) {
1552
1553  // Create the trimmed graph.  It will contain the shortest paths from the
1554  // error nodes to the root.  In the new graph we should only have one
1555  // error node unless there are two or more error nodes with the same minimum
1556  // path length.
1557  ExplodedGraph* GTrim;
1558  InterExplodedGraphMap* NMap;
1559
1560  llvm::DenseMap<const void*, const void*> InverseMap;
1561  llvm::tie(GTrim, NMap) = G->Trim(nodes.data(), nodes.data() + nodes.size(),
1562                                   &InverseMap);
1563
1564  // Create owning pointers for GTrim and NMap just to ensure that they are
1565  // released when this function exists.
1566  OwningPtr<ExplodedGraph> AutoReleaseGTrim(GTrim);
1567  OwningPtr<InterExplodedGraphMap> AutoReleaseNMap(NMap);
1568
1569  // Find the (first) error node in the trimmed graph.  We just need to consult
1570  // the node map (NMap) which maps from nodes in the original graph to nodes
1571  // in the new graph.
1572
1573  std::queue<const ExplodedNode*> WS;
1574  typedef llvm::DenseMap<const ExplodedNode*, unsigned> IndexMapTy;
1575  IndexMapTy IndexMap;
1576
1577  for (unsigned nodeIndex = 0 ; nodeIndex < nodes.size(); ++nodeIndex) {
1578    const ExplodedNode *originalNode = nodes[nodeIndex];
1579    if (const ExplodedNode *N = NMap->getMappedNode(originalNode)) {
1580      WS.push(N);
1581      IndexMap[originalNode] = nodeIndex;
1582    }
1583  }
1584
1585  assert(!WS.empty() && "No error node found in the trimmed graph.");
1586
1587  // Create a new (third!) graph with a single path.  This is the graph
1588  // that will be returned to the caller.
1589  ExplodedGraph *GNew = new ExplodedGraph();
1590
1591  // Sometimes the trimmed graph can contain a cycle.  Perform a reverse BFS
1592  // to the root node, and then construct a new graph that contains only
1593  // a single path.
1594  llvm::DenseMap<const void*,unsigned> Visited;
1595
1596  unsigned cnt = 0;
1597  const ExplodedNode *Root = 0;
1598
1599  while (!WS.empty()) {
1600    const ExplodedNode *Node = WS.front();
1601    WS.pop();
1602
1603    if (Visited.find(Node) != Visited.end())
1604      continue;
1605
1606    Visited[Node] = cnt++;
1607
1608    if (Node->pred_empty()) {
1609      Root = Node;
1610      break;
1611    }
1612
1613    for (ExplodedNode::const_pred_iterator I=Node->pred_begin(),
1614         E=Node->pred_end(); I!=E; ++I)
1615      WS.push(*I);
1616  }
1617
1618  assert(Root);
1619
1620  // Now walk from the root down the BFS path, always taking the successor
1621  // with the lowest number.
1622  ExplodedNode *Last = 0, *First = 0;
1623  NodeBackMap *BM = new NodeBackMap();
1624  unsigned NodeIndex = 0;
1625
1626  for ( const ExplodedNode *N = Root ;;) {
1627    // Lookup the number associated with the current node.
1628    llvm::DenseMap<const void*,unsigned>::iterator I = Visited.find(N);
1629    assert(I != Visited.end());
1630
1631    // Create the equivalent node in the new graph with the same state
1632    // and location.
1633    ExplodedNode *NewN = GNew->getNode(N->getLocation(), N->getState());
1634
1635    // Store the mapping to the original node.
1636    llvm::DenseMap<const void*, const void*>::iterator IMitr=InverseMap.find(N);
1637    assert(IMitr != InverseMap.end() && "No mapping to original node.");
1638    (*BM)[NewN] = (const ExplodedNode*) IMitr->second;
1639
1640    // Link up the new node with the previous node.
1641    if (Last)
1642      NewN->addPredecessor(Last, *GNew);
1643
1644    Last = NewN;
1645
1646    // Are we at the final node?
1647    IndexMapTy::iterator IMI =
1648      IndexMap.find((const ExplodedNode*)(IMitr->second));
1649    if (IMI != IndexMap.end()) {
1650      First = NewN;
1651      NodeIndex = IMI->second;
1652      break;
1653    }
1654
1655    // Find the next successor node.  We choose the node that is marked
1656    // with the lowest DFS number.
1657    ExplodedNode::const_succ_iterator SI = N->succ_begin();
1658    ExplodedNode::const_succ_iterator SE = N->succ_end();
1659    N = 0;
1660
1661    for (unsigned MinVal = 0; SI != SE; ++SI) {
1662
1663      I = Visited.find(*SI);
1664
1665      if (I == Visited.end())
1666        continue;
1667
1668      if (!N || I->second < MinVal) {
1669        N = *SI;
1670        MinVal = I->second;
1671      }
1672    }
1673
1674    assert(N);
1675  }
1676
1677  assert(First);
1678
1679  return std::make_pair(std::make_pair(GNew, BM),
1680                        std::make_pair(First, NodeIndex));
1681}
1682
1683/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object
1684///  and collapses PathDiagosticPieces that are expanded by macros.
1685static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) {
1686  typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>,
1687                                SourceLocation> > MacroStackTy;
1688
1689  typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> >
1690          PiecesTy;
1691
1692  MacroStackTy MacroStack;
1693  PiecesTy Pieces;
1694
1695  for (PathPieces::const_iterator I = path.begin(), E = path.end();
1696       I!=E; ++I) {
1697
1698    PathDiagnosticPiece *piece = I->getPtr();
1699
1700    // Recursively compact calls.
1701    if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){
1702      CompactPathDiagnostic(call->path, SM);
1703    }
1704
1705    // Get the location of the PathDiagnosticPiece.
1706    const FullSourceLoc Loc = piece->getLocation().asLocation();
1707
1708    // Determine the instantiation location, which is the location we group
1709    // related PathDiagnosticPieces.
1710    SourceLocation InstantiationLoc = Loc.isMacroID() ?
1711                                      SM.getExpansionLoc(Loc) :
1712                                      SourceLocation();
1713
1714    if (Loc.isFileID()) {
1715      MacroStack.clear();
1716      Pieces.push_back(piece);
1717      continue;
1718    }
1719
1720    assert(Loc.isMacroID());
1721
1722    // Is the PathDiagnosticPiece within the same macro group?
1723    if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) {
1724      MacroStack.back().first->subPieces.push_back(piece);
1725      continue;
1726    }
1727
1728    // We aren't in the same group.  Are we descending into a new macro
1729    // or are part of an old one?
1730    IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup;
1731
1732    SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ?
1733                                          SM.getExpansionLoc(Loc) :
1734                                          SourceLocation();
1735
1736    // Walk the entire macro stack.
1737    while (!MacroStack.empty()) {
1738      if (InstantiationLoc == MacroStack.back().second) {
1739        MacroGroup = MacroStack.back().first;
1740        break;
1741      }
1742
1743      if (ParentInstantiationLoc == MacroStack.back().second) {
1744        MacroGroup = MacroStack.back().first;
1745        break;
1746      }
1747
1748      MacroStack.pop_back();
1749    }
1750
1751    if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) {
1752      // Create a new macro group and add it to the stack.
1753      PathDiagnosticMacroPiece *NewGroup =
1754        new PathDiagnosticMacroPiece(
1755          PathDiagnosticLocation::createSingleLocation(piece->getLocation()));
1756
1757      if (MacroGroup)
1758        MacroGroup->subPieces.push_back(NewGroup);
1759      else {
1760        assert(InstantiationLoc.isFileID());
1761        Pieces.push_back(NewGroup);
1762      }
1763
1764      MacroGroup = NewGroup;
1765      MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc));
1766    }
1767
1768    // Finally, add the PathDiagnosticPiece to the group.
1769    MacroGroup->subPieces.push_back(piece);
1770  }
1771
1772  // Now take the pieces and construct a new PathDiagnostic.
1773  path.clear();
1774
1775  for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I)
1776    path.push_back(*I);
1777}
1778
1779void GRBugReporter::GeneratePathDiagnostic(PathDiagnostic& PD,
1780                        SmallVectorImpl<BugReport *> &bugReports) {
1781
1782  assert(!bugReports.empty());
1783  SmallVector<const ExplodedNode *, 10> errorNodes;
1784  for (SmallVectorImpl<BugReport*>::iterator I = bugReports.begin(),
1785    E = bugReports.end(); I != E; ++I) {
1786      errorNodes.push_back((*I)->getErrorNode());
1787  }
1788
1789  // Construct a new graph that contains only a single path from the error
1790  // node to a root.
1791  const std::pair<std::pair<ExplodedGraph*, NodeBackMap*>,
1792  std::pair<ExplodedNode*, unsigned> >&
1793    GPair = MakeReportGraph(&getGraph(), errorNodes);
1794
1795  // Find the BugReport with the original location.
1796  assert(GPair.second.second < bugReports.size());
1797  BugReport *R = bugReports[GPair.second.second];
1798  assert(R && "No original report found for sliced graph.");
1799
1800  OwningPtr<ExplodedGraph> ReportGraph(GPair.first.first);
1801  OwningPtr<NodeBackMap> BackMap(GPair.first.second);
1802  const ExplodedNode *N = GPair.second.first;
1803
1804  // Start building the path diagnostic...
1805  PathDiagnosticBuilder PDB(*this, R, BackMap.get(),
1806                            getPathDiagnosticConsumer());
1807
1808  // Register additional node visitors.
1809  R->addVisitor(new NilReceiverBRVisitor());
1810  R->addVisitor(new ConditionBRVisitor());
1811
1812  BugReport::VisitorList visitors;
1813  unsigned originalReportConfigToken, finalReportConfigToken;
1814
1815  // While generating diagnostics, it's possible the visitors will decide
1816  // new symbols and regions are interesting, or add other visitors based on
1817  // the information they find. If they do, we need to regenerate the path
1818  // based on our new report configuration.
1819  do {
1820    // Get a clean copy of all the visitors.
1821    for (BugReport::visitor_iterator I = R->visitor_begin(),
1822                                     E = R->visitor_end(); I != E; ++I)
1823       visitors.push_back((*I)->clone());
1824
1825    // Clear out the active path from any previous work.
1826    PD.getActivePath().clear();
1827    originalReportConfigToken = R->getConfigurationChangeToken();
1828
1829    // Generate the very last diagnostic piece - the piece is visible before
1830    // the trace is expanded.
1831    PathDiagnosticPiece *LastPiece = 0;
1832    for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end();
1833         I != E; ++I) {
1834      if (PathDiagnosticPiece *Piece = (*I)->getEndPath(PDB, N, *R)) {
1835        assert (!LastPiece &&
1836                "There can only be one final piece in a diagnostic.");
1837        LastPiece = Piece;
1838      }
1839    }
1840    if (!LastPiece)
1841      LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R);
1842    if (LastPiece)
1843      PD.getActivePath().push_back(LastPiece);
1844    else
1845      return;
1846
1847    switch (PDB.getGenerationScheme()) {
1848    case PathDiagnosticConsumer::Extensive:
1849      GenerateExtensivePathDiagnostic(PD, PDB, N, visitors);
1850      break;
1851    case PathDiagnosticConsumer::Minimal:
1852      GenerateMinimalPathDiagnostic(PD, PDB, N, visitors);
1853      break;
1854    }
1855
1856    // Clean up the visitors we used.
1857    llvm::DeleteContainerPointers(visitors);
1858
1859    // Did anything change while generating this path?
1860    finalReportConfigToken = R->getConfigurationChangeToken();
1861  } while(finalReportConfigToken != originalReportConfigToken);
1862
1863  // Finally, prune the diagnostic path of uninteresting stuff.
1864  bool hasSomethingInteresting = RemoveUneededCalls(PD.getMutablePieces());
1865  assert(hasSomethingInteresting);
1866  (void) hasSomethingInteresting;
1867}
1868
1869void BugReporter::Register(BugType *BT) {
1870  BugTypes = F.add(BugTypes, BT);
1871}
1872
1873void BugReporter::EmitReport(BugReport* R) {
1874  // Compute the bug report's hash to determine its equivalence class.
1875  llvm::FoldingSetNodeID ID;
1876  R->Profile(ID);
1877
1878  // Lookup the equivance class.  If there isn't one, create it.
1879  BugType& BT = R->getBugType();
1880  Register(&BT);
1881  void *InsertPos;
1882  BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos);
1883
1884  if (!EQ) {
1885    EQ = new BugReportEquivClass(R);
1886    EQClasses.InsertNode(EQ, InsertPos);
1887    EQClassesVector.push_back(EQ);
1888  }
1889  else
1890    EQ->AddReport(R);
1891}
1892
1893
1894//===----------------------------------------------------------------------===//
1895// Emitting reports in equivalence classes.
1896//===----------------------------------------------------------------------===//
1897
1898namespace {
1899struct FRIEC_WLItem {
1900  const ExplodedNode *N;
1901  ExplodedNode::const_succ_iterator I, E;
1902
1903  FRIEC_WLItem(const ExplodedNode *n)
1904  : N(n), I(N->succ_begin()), E(N->succ_end()) {}
1905};
1906}
1907
1908static BugReport *
1909FindReportInEquivalenceClass(BugReportEquivClass& EQ,
1910                             SmallVectorImpl<BugReport*> &bugReports) {
1911
1912  BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end();
1913  assert(I != E);
1914  BugType& BT = I->getBugType();
1915
1916  // If we don't need to suppress any of the nodes because they are
1917  // post-dominated by a sink, simply add all the nodes in the equivalence class
1918  // to 'Nodes'.  Any of the reports will serve as a "representative" report.
1919  if (!BT.isSuppressOnSink()) {
1920    BugReport *R = I;
1921    for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) {
1922      const ExplodedNode *N = I->getErrorNode();
1923      if (N) {
1924        R = I;
1925        bugReports.push_back(R);
1926      }
1927    }
1928    return R;
1929  }
1930
1931  // For bug reports that should be suppressed when all paths are post-dominated
1932  // by a sink node, iterate through the reports in the equivalence class
1933  // until we find one that isn't post-dominated (if one exists).  We use a
1934  // DFS traversal of the ExplodedGraph to find a non-sink node.  We could write
1935  // this as a recursive function, but we don't want to risk blowing out the
1936  // stack for very long paths.
1937  BugReport *exampleReport = 0;
1938
1939  for (; I != E; ++I) {
1940    const ExplodedNode *errorNode = I->getErrorNode();
1941
1942    if (!errorNode)
1943      continue;
1944    if (errorNode->isSink()) {
1945      llvm_unreachable(
1946           "BugType::isSuppressSink() should not be 'true' for sink end nodes");
1947    }
1948    // No successors?  By definition this nodes isn't post-dominated by a sink.
1949    if (errorNode->succ_empty()) {
1950      bugReports.push_back(I);
1951      if (!exampleReport)
1952        exampleReport = I;
1953      continue;
1954    }
1955
1956    // At this point we know that 'N' is not a sink and it has at least one
1957    // successor.  Use a DFS worklist to find a non-sink end-of-path node.
1958    typedef FRIEC_WLItem WLItem;
1959    typedef SmallVector<WLItem, 10> DFSWorkList;
1960    llvm::DenseMap<const ExplodedNode *, unsigned> Visited;
1961
1962    DFSWorkList WL;
1963    WL.push_back(errorNode);
1964    Visited[errorNode] = 1;
1965
1966    while (!WL.empty()) {
1967      WLItem &WI = WL.back();
1968      assert(!WI.N->succ_empty());
1969
1970      for (; WI.I != WI.E; ++WI.I) {
1971        const ExplodedNode *Succ = *WI.I;
1972        // End-of-path node?
1973        if (Succ->succ_empty()) {
1974          // If we found an end-of-path node that is not a sink.
1975          if (!Succ->isSink()) {
1976            bugReports.push_back(I);
1977            if (!exampleReport)
1978              exampleReport = I;
1979            WL.clear();
1980            break;
1981          }
1982          // Found a sink?  Continue on to the next successor.
1983          continue;
1984        }
1985        // Mark the successor as visited.  If it hasn't been explored,
1986        // enqueue it to the DFS worklist.
1987        unsigned &mark = Visited[Succ];
1988        if (!mark) {
1989          mark = 1;
1990          WL.push_back(Succ);
1991          break;
1992        }
1993      }
1994
1995      // The worklist may have been cleared at this point.  First
1996      // check if it is empty before checking the last item.
1997      if (!WL.empty() && &WL.back() == &WI)
1998        WL.pop_back();
1999    }
2000  }
2001
2002  // ExampleReport will be NULL if all the nodes in the equivalence class
2003  // were post-dominated by sinks.
2004  return exampleReport;
2005}
2006
2007//===----------------------------------------------------------------------===//
2008// DiagnosticCache.  This is a hack to cache analyzer diagnostics.  It
2009// uses global state, which eventually should go elsewhere.
2010//===----------------------------------------------------------------------===//
2011namespace {
2012class DiagCacheItem : public llvm::FoldingSetNode {
2013  llvm::FoldingSetNodeID ID;
2014public:
2015  DiagCacheItem(BugReport *R, PathDiagnostic *PD) {
2016    R->Profile(ID);
2017    PD->Profile(ID);
2018  }
2019
2020  void Profile(llvm::FoldingSetNodeID &id) {
2021    id = ID;
2022  }
2023
2024  llvm::FoldingSetNodeID &getID() { return ID; }
2025};
2026}
2027
2028static bool IsCachedDiagnostic(BugReport *R, PathDiagnostic *PD) {
2029  // FIXME: Eventually this diagnostic cache should reside in something
2030  // like AnalysisManager instead of being a static variable.  This is
2031  // really unsafe in the long term.
2032  typedef llvm::FoldingSet<DiagCacheItem> DiagnosticCache;
2033  static DiagnosticCache DC;
2034
2035  void *InsertPos;
2036  DiagCacheItem *Item = new DiagCacheItem(R, PD);
2037
2038  if (DC.FindNodeOrInsertPos(Item->getID(), InsertPos)) {
2039    delete Item;
2040    return true;
2041  }
2042
2043  DC.InsertNode(Item, InsertPos);
2044  return false;
2045}
2046
2047void BugReporter::FlushReport(BugReportEquivClass& EQ) {
2048  SmallVector<BugReport*, 10> bugReports;
2049  BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports);
2050  if (!exampleReport)
2051    return;
2052
2053  PathDiagnosticConsumer* PD = getPathDiagnosticConsumer();
2054
2055  // FIXME: Make sure we use the 'R' for the path that was actually used.
2056  // Probably doesn't make a difference in practice.
2057  BugType& BT = exampleReport->getBugType();
2058
2059  OwningPtr<PathDiagnostic>
2060    D(new PathDiagnostic(exampleReport->getDeclWithIssue(),
2061                         exampleReport->getBugType().getName(),
2062                         !PD || PD->useVerboseDescription()
2063                         ? exampleReport->getDescription()
2064                         : exampleReport->getShortDescription(),
2065                         BT.getCategory()));
2066
2067  if (!bugReports.empty())
2068    GeneratePathDiagnostic(*D.get(), bugReports);
2069
2070  // Get the meta data.
2071  const BugReport::ExtraTextList &Meta =
2072                                  exampleReport->getExtraText();
2073  for (BugReport::ExtraTextList::const_iterator i = Meta.begin(),
2074                                                e = Meta.end(); i != e; ++i) {
2075    D->addMeta(*i);
2076  }
2077
2078  // Emit a summary diagnostic to the regular Diagnostics engine.
2079  BugReport::ranges_iterator Beg, End;
2080  llvm::tie(Beg, End) = exampleReport->getRanges();
2081  DiagnosticsEngine &Diag = getDiagnostic();
2082
2083  if (!IsCachedDiagnostic(exampleReport, D.get())) {
2084    // Search the description for '%', as that will be interpretted as a
2085    // format character by FormatDiagnostics.
2086    StringRef desc = exampleReport->getShortDescription();
2087
2088    SmallString<512> TmpStr;
2089    llvm::raw_svector_ostream Out(TmpStr);
2090    for (StringRef::iterator I=desc.begin(), E=desc.end(); I!=E; ++I) {
2091      if (*I == '%')
2092        Out << "%%";
2093      else
2094        Out << *I;
2095    }
2096
2097    Out.flush();
2098    unsigned ErrorDiag = Diag.getCustomDiagID(DiagnosticsEngine::Warning, TmpStr);
2099
2100    DiagnosticBuilder diagBuilder = Diag.Report(
2101      exampleReport->getLocation(getSourceManager()).asLocation(), ErrorDiag);
2102    for (BugReport::ranges_iterator I = Beg; I != End; ++I)
2103      diagBuilder << *I;
2104  }
2105
2106  // Emit a full diagnostic for the path if we have a PathDiagnosticConsumer.
2107  if (!PD)
2108    return;
2109
2110  if (D->path.empty()) {
2111    PathDiagnosticPiece *piece = new PathDiagnosticEventPiece(
2112                                 exampleReport->getLocation(getSourceManager()),
2113                                 exampleReport->getDescription());
2114    for ( ; Beg != End; ++Beg)
2115      piece->addRange(*Beg);
2116
2117    D->getActivePath().push_back(piece);
2118  }
2119
2120  PD->HandlePathDiagnostic(D.take());
2121}
2122
2123void BugReporter::EmitBasicReport(const Decl *DeclWithIssue,
2124                                  StringRef name,
2125                                  StringRef category,
2126                                  StringRef str, PathDiagnosticLocation Loc,
2127                                  SourceRange* RBeg, unsigned NumRanges) {
2128
2129  // 'BT' is owned by BugReporter.
2130  BugType *BT = getBugTypeForName(name, category);
2131  BugReport *R = new BugReport(*BT, str, Loc);
2132  R->setDeclWithIssue(DeclWithIssue);
2133  for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg);
2134  EmitReport(R);
2135}
2136
2137BugType *BugReporter::getBugTypeForName(StringRef name,
2138                                        StringRef category) {
2139  SmallString<136> fullDesc;
2140  llvm::raw_svector_ostream(fullDesc) << name << ":" << category;
2141  llvm::StringMapEntry<BugType *> &
2142      entry = StrBugTypes.GetOrCreateValue(fullDesc);
2143  BugType *BT = entry.getValue();
2144  if (!BT) {
2145    BT = new BugType(name, category);
2146    entry.setValue(BT);
2147  }
2148  return BT;
2149}
2150