BugReporter.cpp revision 3a46f5fd1709f6df03bbb8b0abf84052dc0f39ff 
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  else if (const CallEnter *CE = dyn_cast<CallEnter>(&P))
52    return CE->getCallExpr();
53  else if (const CallExitEnd *CEE = dyn_cast<CallExitEnd>(&P))
54    return CEE->getCalleeContext()->getCallSite();
55
56  return 0;
57}
58
59static inline const ExplodedNode*
60GetPredecessorNode(const ExplodedNode *N) {
61  return N->pred_empty() ? NULL : *(N->pred_begin());
62}
63
64static inline const ExplodedNode*
65GetSuccessorNode(const ExplodedNode *N) {
66  return N->succ_empty() ? NULL : *(N->succ_begin());
67}
68
69static const Stmt *GetPreviousStmt(const ExplodedNode *N) {
70  for (N = GetPredecessorNode(N); N; N = GetPredecessorNode(N))
71    if (const Stmt *S = GetStmt(N->getLocation()))
72      return S;
73
74  return 0;
75}
76
77static const Stmt *GetNextStmt(const ExplodedNode *N) {
78  for (N = GetSuccessorNode(N); N; N = GetSuccessorNode(N))
79    if (const Stmt *S = GetStmt(N->getLocation())) {
80      // Check if the statement is '?' or '&&'/'||'.  These are "merges",
81      // not actual statement points.
82      switch (S->getStmtClass()) {
83        case Stmt::ChooseExprClass:
84        case Stmt::BinaryConditionalOperatorClass: continue;
85        case Stmt::ConditionalOperatorClass: continue;
86        case Stmt::BinaryOperatorClass: {
87          BinaryOperatorKind Op = cast<BinaryOperator>(S)->getOpcode();
88          if (Op == BO_LAnd || Op == BO_LOr)
89            continue;
90          break;
91        }
92        default:
93          break;
94      }
95      return S;
96    }
97
98  return 0;
99}
100
101static inline const Stmt*
102GetCurrentOrPreviousStmt(const ExplodedNode *N) {
103  if (const Stmt *S = GetStmt(N->getLocation()))
104    return S;
105
106  return GetPreviousStmt(N);
107}
108
109static inline const Stmt*
110GetCurrentOrNextStmt(const ExplodedNode *N) {
111  if (const Stmt *S = GetStmt(N->getLocation()))
112    return S;
113
114  return GetNextStmt(N);
115}
116
117//===----------------------------------------------------------------------===//
118// Diagnostic cleanup.
119//===----------------------------------------------------------------------===//
120
121/// Recursively scan through a path and prune out calls and macros pieces
122/// that aren't needed.  Return true if afterwards the path contains
123/// "interesting stuff" which means it should be pruned from the parent path.
124bool BugReporter::RemoveUneededCalls(PathPieces &pieces, BugReport *R) {
125  bool containsSomethingInteresting = false;
126  const unsigned N = pieces.size();
127
128  for (unsigned i = 0 ; i < N ; ++i) {
129    // Remove the front piece from the path.  If it is still something we
130    // want to keep once we are done, we will push it back on the end.
131    IntrusiveRefCntPtr<PathDiagnosticPiece> piece(pieces.front());
132    pieces.pop_front();
133
134    switch (piece->getKind()) {
135      case PathDiagnosticPiece::Call: {
136        PathDiagnosticCallPiece *call = cast<PathDiagnosticCallPiece>(piece);
137        // Check if the location context is interesting.
138        assert(LocationContextMap.count(call));
139        if (R->isInteresting(LocationContextMap[call])) {
140          containsSomethingInteresting = true;
141          break;
142        }
143        // Recursively clean out the subclass.  Keep this call around if
144        // it contains any informative diagnostics.
145        if (!RemoveUneededCalls(call->path, R))
146          continue;
147        containsSomethingInteresting = true;
148        break;
149      }
150      case PathDiagnosticPiece::Macro: {
151        PathDiagnosticMacroPiece *macro = cast<PathDiagnosticMacroPiece>(piece);
152        if (!RemoveUneededCalls(macro->subPieces, R))
153          continue;
154        containsSomethingInteresting = true;
155        break;
156      }
157      case PathDiagnosticPiece::Event: {
158        PathDiagnosticEventPiece *event = cast<PathDiagnosticEventPiece>(piece);
159        // We never throw away an event, but we do throw it away wholesale
160        // as part of a path if we throw the entire path away.
161        if (event->isPrunable())
162          continue;
163        containsSomethingInteresting = true;
164        break;
165      }
166      case PathDiagnosticPiece::ControlFlow:
167        break;
168    }
169
170    pieces.push_back(piece);
171  }
172
173  return containsSomethingInteresting;
174}
175
176//===----------------------------------------------------------------------===//
177// PathDiagnosticBuilder and its associated routines and helper objects.
178//===----------------------------------------------------------------------===//
179
180typedef llvm::DenseMap<const ExplodedNode*,
181const ExplodedNode*> NodeBackMap;
182
183namespace {
184class NodeMapClosure : public BugReport::NodeResolver {
185  NodeBackMap& M;
186public:
187  NodeMapClosure(NodeBackMap *m) : M(*m) {}
188  ~NodeMapClosure() {}
189
190  const ExplodedNode *getOriginalNode(const ExplodedNode *N) {
191    NodeBackMap::iterator I = M.find(N);
192    return I == M.end() ? 0 : I->second;
193  }
194};
195
196class PathDiagnosticBuilder : public BugReporterContext {
197  BugReport *R;
198  PathDiagnosticConsumer *PDC;
199  OwningPtr<ParentMap> PM;
200  NodeMapClosure NMC;
201public:
202  const LocationContext *LC;
203
204  PathDiagnosticBuilder(GRBugReporter &br,
205                        BugReport *r, NodeBackMap *Backmap,
206                        PathDiagnosticConsumer *pdc)
207    : BugReporterContext(br),
208      R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext())
209  {}
210
211  PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N);
212
213  PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os,
214                                            const ExplodedNode *N);
215
216  BugReport *getBugReport() { return R; }
217
218  Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); }
219
220  ParentMap& getParentMap() { return LC->getParentMap(); }
221
222  const Stmt *getParent(const Stmt *S) {
223    return getParentMap().getParent(S);
224  }
225
226  virtual NodeMapClosure& getNodeResolver() { return NMC; }
227
228  PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S);
229
230  PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const {
231    return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive;
232  }
233
234  bool supportsLogicalOpControlFlow() const {
235    return PDC ? PDC->supportsLogicalOpControlFlow() : true;
236  }
237};
238} // end anonymous namespace
239
240PathDiagnosticLocation
241PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) {
242  if (const Stmt *S = GetNextStmt(N))
243    return PathDiagnosticLocation(S, getSourceManager(), LC);
244
245  return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(),
246                                               getSourceManager());
247}
248
249PathDiagnosticLocation
250PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os,
251                                          const ExplodedNode *N) {
252
253  // Slow, but probably doesn't matter.
254  if (os.str().empty())
255    os << ' ';
256
257  const PathDiagnosticLocation &Loc = ExecutionContinues(N);
258
259  if (Loc.asStmt())
260    os << "Execution continues on line "
261       << getSourceManager().getExpansionLineNumber(Loc.asLocation())
262       << '.';
263  else {
264    os << "Execution jumps to the end of the ";
265    const Decl *D = N->getLocationContext()->getDecl();
266    if (isa<ObjCMethodDecl>(D))
267      os << "method";
268    else if (isa<FunctionDecl>(D))
269      os << "function";
270    else {
271      assert(isa<BlockDecl>(D));
272      os << "anonymous block";
273    }
274    os << '.';
275  }
276
277  return Loc;
278}
279
280static bool IsNested(const Stmt *S, ParentMap &PM) {
281  if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S)))
282    return true;
283
284  const Stmt *Parent = PM.getParentIgnoreParens(S);
285
286  if (Parent)
287    switch (Parent->getStmtClass()) {
288      case Stmt::ForStmtClass:
289      case Stmt::DoStmtClass:
290      case Stmt::WhileStmtClass:
291        return true;
292      default:
293        break;
294    }
295
296  return false;
297}
298
299PathDiagnosticLocation
300PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) {
301  assert(S && "Null Stmt *passed to getEnclosingStmtLocation");
302  ParentMap &P = getParentMap();
303  SourceManager &SMgr = getSourceManager();
304
305  while (IsNested(S, P)) {
306    const Stmt *Parent = P.getParentIgnoreParens(S);
307
308    if (!Parent)
309      break;
310
311    switch (Parent->getStmtClass()) {
312      case Stmt::BinaryOperatorClass: {
313        const BinaryOperator *B = cast<BinaryOperator>(Parent);
314        if (B->isLogicalOp())
315          return PathDiagnosticLocation(S, SMgr, LC);
316        break;
317      }
318      case Stmt::CompoundStmtClass:
319      case Stmt::StmtExprClass:
320        return PathDiagnosticLocation(S, SMgr, LC);
321      case Stmt::ChooseExprClass:
322        // Similar to '?' if we are referring to condition, just have the edge
323        // point to the entire choose expression.
324        if (cast<ChooseExpr>(Parent)->getCond() == S)
325          return PathDiagnosticLocation(Parent, SMgr, LC);
326        else
327          return PathDiagnosticLocation(S, SMgr, LC);
328      case Stmt::BinaryConditionalOperatorClass:
329      case Stmt::ConditionalOperatorClass:
330        // For '?', if we are referring to condition, just have the edge point
331        // to the entire '?' expression.
332        if (cast<AbstractConditionalOperator>(Parent)->getCond() == S)
333          return PathDiagnosticLocation(Parent, SMgr, LC);
334        else
335          return PathDiagnosticLocation(S, SMgr, LC);
336      case Stmt::DoStmtClass:
337          return PathDiagnosticLocation(S, SMgr, LC);
338      case Stmt::ForStmtClass:
339        if (cast<ForStmt>(Parent)->getBody() == S)
340          return PathDiagnosticLocation(S, SMgr, LC);
341        break;
342      case Stmt::IfStmtClass:
343        if (cast<IfStmt>(Parent)->getCond() != S)
344          return PathDiagnosticLocation(S, SMgr, LC);
345        break;
346      case Stmt::ObjCForCollectionStmtClass:
347        if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S)
348          return PathDiagnosticLocation(S, SMgr, LC);
349        break;
350      case Stmt::WhileStmtClass:
351        if (cast<WhileStmt>(Parent)->getCond() != S)
352          return PathDiagnosticLocation(S, SMgr, LC);
353        break;
354      default:
355        break;
356    }
357
358    S = Parent;
359  }
360
361  assert(S && "Cannot have null Stmt for PathDiagnosticLocation");
362
363  // Special case: DeclStmts can appear in for statement declarations, in which
364  //  case the ForStmt is the context.
365  if (isa<DeclStmt>(S)) {
366    if (const Stmt *Parent = P.getParent(S)) {
367      switch (Parent->getStmtClass()) {
368        case Stmt::ForStmtClass:
369        case Stmt::ObjCForCollectionStmtClass:
370          return PathDiagnosticLocation(Parent, SMgr, LC);
371        default:
372          break;
373      }
374    }
375  }
376  else if (isa<BinaryOperator>(S)) {
377    // Special case: the binary operator represents the initialization
378    // code in a for statement (this can happen when the variable being
379    // initialized is an old variable.
380    if (const ForStmt *FS =
381          dyn_cast_or_null<ForStmt>(P.getParentIgnoreParens(S))) {
382      if (FS->getInit() == S)
383        return PathDiagnosticLocation(FS, SMgr, LC);
384    }
385  }
386
387  return PathDiagnosticLocation(S, SMgr, LC);
388}
389
390//===----------------------------------------------------------------------===//
391// "Minimal" path diagnostic generation algorithm.
392//===----------------------------------------------------------------------===//
393typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair;
394typedef SmallVector<StackDiagPair, 6> StackDiagVector;
395
396static void updateStackPiecesWithMessage(PathDiagnosticPiece *P,
397                                         StackDiagVector &CallStack) {
398  // If the piece contains a special message, add it to all the call
399  // pieces on the active stack.
400  if (PathDiagnosticEventPiece *ep =
401        dyn_cast<PathDiagnosticEventPiece>(P)) {
402
403    if (ep->hasCallStackHint())
404      for (StackDiagVector::iterator I = CallStack.begin(),
405                                     E = CallStack.end(); I != E; ++I) {
406        PathDiagnosticCallPiece *CP = I->first;
407        const ExplodedNode *N = I->second;
408        std::string stackMsg = ep->getCallStackMessage(N);
409
410        // The last message on the path to final bug is the most important
411        // one. Since we traverse the path backwards, do not add the message
412        // if one has been previously added.
413        if  (!CP->hasCallStackMessage())
414          CP->setCallStackMessage(stackMsg);
415      }
416  }
417}
418
419static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM);
420
421static void GenerateMinimalPathDiagnostic(PathDiagnostic& PD,
422                                          PathDiagnosticBuilder &PDB,
423                                          const ExplodedNode *N,
424                                      ArrayRef<BugReporterVisitor *> visitors) {
425
426  SourceManager& SMgr = PDB.getSourceManager();
427  const LocationContext *LC = PDB.LC;
428  const ExplodedNode *NextNode = N->pred_empty()
429                                        ? NULL : *(N->pred_begin());
430
431  StackDiagVector CallStack;
432
433  while (NextNode) {
434    N = NextNode;
435    PDB.LC = N->getLocationContext();
436    NextNode = GetPredecessorNode(N);
437
438    ProgramPoint P = N->getLocation();
439
440    do {
441      if (const CallExitEnd *CE = dyn_cast<CallExitEnd>(&P)) {
442        PathDiagnosticCallPiece *C =
443            PathDiagnosticCallPiece::construct(N, *CE, SMgr);
444        GRBugReporter& BR = PDB.getBugReporter();
445        BR.addCallPieceLocationContextPair(C, CE->getCalleeContext());
446        PD.getActivePath().push_front(C);
447        PD.pushActivePath(&C->path);
448        CallStack.push_back(StackDiagPair(C, N));
449        break;
450      }
451
452      if (const CallEnter *CE = dyn_cast<CallEnter>(&P)) {
453        // Flush all locations, and pop the active path.
454        bool VisitedEntireCall = PD.isWithinCall();
455        PD.popActivePath();
456
457        // Either we just added a bunch of stuff to the top-level path, or
458        // we have a previous CallExitEnd.  If the former, it means that the
459        // path terminated within a function call.  We must then take the
460        // current contents of the active path and place it within
461        // a new PathDiagnosticCallPiece.
462        PathDiagnosticCallPiece *C;
463        if (VisitedEntireCall) {
464          C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
465        } else {
466          const Decl *Caller = CE->getLocationContext()->getDecl();
467          C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
468          GRBugReporter& BR = PDB.getBugReporter();
469          BR.addCallPieceLocationContextPair(C, CE->getCalleeContext());
470        }
471
472        C->setCallee(*CE, SMgr);
473        if (!CallStack.empty()) {
474          assert(CallStack.back().first == C);
475          CallStack.pop_back();
476        }
477        break;
478      }
479
480      if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
481        const CFGBlock *Src = BE->getSrc();
482        const CFGBlock *Dst = BE->getDst();
483        const Stmt *T = Src->getTerminator();
484
485        if (!T)
486          break;
487
488        PathDiagnosticLocation Start =
489            PathDiagnosticLocation::createBegin(T, SMgr,
490                N->getLocationContext());
491
492        switch (T->getStmtClass()) {
493        default:
494          break;
495
496        case Stmt::GotoStmtClass:
497        case Stmt::IndirectGotoStmtClass: {
498          const Stmt *S = GetNextStmt(N);
499
500          if (!S)
501            break;
502
503          std::string sbuf;
504          llvm::raw_string_ostream os(sbuf);
505          const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S);
506
507          os << "Control jumps to line "
508              << End.asLocation().getExpansionLineNumber();
509          PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
510              Start, End, os.str()));
511          break;
512        }
513
514        case Stmt::SwitchStmtClass: {
515          // Figure out what case arm we took.
516          std::string sbuf;
517          llvm::raw_string_ostream os(sbuf);
518
519          if (const Stmt *S = Dst->getLabel()) {
520            PathDiagnosticLocation End(S, SMgr, LC);
521
522            switch (S->getStmtClass()) {
523            default:
524              os << "No cases match in the switch statement. "
525              "Control jumps to line "
526              << End.asLocation().getExpansionLineNumber();
527              break;
528            case Stmt::DefaultStmtClass:
529              os << "Control jumps to the 'default' case at line "
530              << End.asLocation().getExpansionLineNumber();
531              break;
532
533            case Stmt::CaseStmtClass: {
534              os << "Control jumps to 'case ";
535              const CaseStmt *Case = cast<CaseStmt>(S);
536              const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
537
538              // Determine if it is an enum.
539              bool GetRawInt = true;
540
541              if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) {
542                // FIXME: Maybe this should be an assertion.  Are there cases
543                // were it is not an EnumConstantDecl?
544                const EnumConstantDecl *D =
545                    dyn_cast<EnumConstantDecl>(DR->getDecl());
546
547                if (D) {
548                  GetRawInt = false;
549                  os << *D;
550                }
551              }
552
553              if (GetRawInt)
554                os << LHS->EvaluateKnownConstInt(PDB.getASTContext());
555
556              os << ":'  at line "
557                  << End.asLocation().getExpansionLineNumber();
558              break;
559            }
560            }
561            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
562                Start, End, os.str()));
563          }
564          else {
565            os << "'Default' branch taken. ";
566            const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N);
567            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
568                Start, End, os.str()));
569          }
570
571          break;
572        }
573
574        case Stmt::BreakStmtClass:
575        case Stmt::ContinueStmtClass: {
576          std::string sbuf;
577          llvm::raw_string_ostream os(sbuf);
578          PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
579          PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
580              Start, End, os.str()));
581          break;
582        }
583
584        // Determine control-flow for ternary '?'.
585        case Stmt::BinaryConditionalOperatorClass:
586        case Stmt::ConditionalOperatorClass: {
587          std::string sbuf;
588          llvm::raw_string_ostream os(sbuf);
589          os << "'?' condition is ";
590
591          if (*(Src->succ_begin()+1) == Dst)
592            os << "false";
593          else
594            os << "true";
595
596          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
597
598          if (const Stmt *S = End.asStmt())
599            End = PDB.getEnclosingStmtLocation(S);
600
601          PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
602              Start, End, os.str()));
603          break;
604        }
605
606        // Determine control-flow for short-circuited '&&' and '||'.
607        case Stmt::BinaryOperatorClass: {
608          if (!PDB.supportsLogicalOpControlFlow())
609            break;
610
611          const BinaryOperator *B = cast<BinaryOperator>(T);
612          std::string sbuf;
613          llvm::raw_string_ostream os(sbuf);
614          os << "Left side of '";
615
616          if (B->getOpcode() == BO_LAnd) {
617            os << "&&" << "' is ";
618
619            if (*(Src->succ_begin()+1) == Dst) {
620              os << "false";
621              PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
622              PathDiagnosticLocation Start =
623                  PathDiagnosticLocation::createOperatorLoc(B, SMgr);
624              PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
625                  Start, End, os.str()));
626            }
627            else {
628              os << "true";
629              PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
630              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
631              PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
632                  Start, End, os.str()));
633            }
634          }
635          else {
636            assert(B->getOpcode() == BO_LOr);
637            os << "||" << "' is ";
638
639            if (*(Src->succ_begin()+1) == Dst) {
640              os << "false";
641              PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
642              PathDiagnosticLocation End = PDB.ExecutionContinues(N);
643              PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
644                  Start, End, os.str()));
645            }
646            else {
647              os << "true";
648              PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
649              PathDiagnosticLocation Start =
650                  PathDiagnosticLocation::createOperatorLoc(B, SMgr);
651              PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
652                  Start, End, os.str()));
653            }
654          }
655
656          break;
657        }
658
659        case Stmt::DoStmtClass:  {
660          if (*(Src->succ_begin()) == Dst) {
661            std::string sbuf;
662            llvm::raw_string_ostream os(sbuf);
663
664            os << "Loop condition is true. ";
665            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
666
667            if (const Stmt *S = End.asStmt())
668              End = PDB.getEnclosingStmtLocation(S);
669
670            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
671                Start, End, os.str()));
672          }
673          else {
674            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
675
676            if (const Stmt *S = End.asStmt())
677              End = PDB.getEnclosingStmtLocation(S);
678
679            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
680                Start, End, "Loop condition is false.  Exiting loop"));
681          }
682
683          break;
684        }
685
686        case Stmt::WhileStmtClass:
687        case Stmt::ForStmtClass: {
688          if (*(Src->succ_begin()+1) == Dst) {
689            std::string sbuf;
690            llvm::raw_string_ostream os(sbuf);
691
692            os << "Loop condition is false. ";
693            PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
694            if (const Stmt *S = End.asStmt())
695              End = PDB.getEnclosingStmtLocation(S);
696
697            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
698                Start, End, os.str()));
699          }
700          else {
701            PathDiagnosticLocation End = PDB.ExecutionContinues(N);
702            if (const Stmt *S = End.asStmt())
703              End = PDB.getEnclosingStmtLocation(S);
704
705            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
706                Start, End, "Loop condition is true.  Entering loop body"));
707          }
708
709          break;
710        }
711
712        case Stmt::IfStmtClass: {
713          PathDiagnosticLocation End = PDB.ExecutionContinues(N);
714
715          if (const Stmt *S = End.asStmt())
716            End = PDB.getEnclosingStmtLocation(S);
717
718          if (*(Src->succ_begin()+1) == Dst)
719            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
720                Start, End, "Taking false branch"));
721          else
722            PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
723                Start, End, "Taking true branch"));
724
725          break;
726        }
727        }
728      }
729    } while(0);
730
731    if (NextNode) {
732      // Add diagnostic pieces from custom visitors.
733      BugReport *R = PDB.getBugReport();
734      for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(),
735                                                    E = visitors.end();
736           I != E; ++I) {
737        if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) {
738          PD.getActivePath().push_front(p);
739          updateStackPiecesWithMessage(p, CallStack);
740        }
741      }
742    }
743  }
744
745  // After constructing the full PathDiagnostic, do a pass over it to compact
746  // PathDiagnosticPieces that occur within a macro.
747  CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager());
748}
749
750//===----------------------------------------------------------------------===//
751// "Extensive" PathDiagnostic generation.
752//===----------------------------------------------------------------------===//
753
754static bool IsControlFlowExpr(const Stmt *S) {
755  const Expr *E = dyn_cast<Expr>(S);
756
757  if (!E)
758    return false;
759
760  E = E->IgnoreParenCasts();
761
762  if (isa<AbstractConditionalOperator>(E))
763    return true;
764
765  if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E))
766    if (B->isLogicalOp())
767      return true;
768
769  return false;
770}
771
772namespace {
773class ContextLocation : public PathDiagnosticLocation {
774  bool IsDead;
775public:
776  ContextLocation(const PathDiagnosticLocation &L, bool isdead = false)
777    : PathDiagnosticLocation(L), IsDead(isdead) {}
778
779  void markDead() { IsDead = true; }
780  bool isDead() const { return IsDead; }
781};
782
783class EdgeBuilder {
784  std::vector<ContextLocation> CLocs;
785  typedef std::vector<ContextLocation>::iterator iterator;
786  PathDiagnostic &PD;
787  PathDiagnosticBuilder &PDB;
788  PathDiagnosticLocation PrevLoc;
789
790  bool IsConsumedExpr(const PathDiagnosticLocation &L);
791
792  bool containsLocation(const PathDiagnosticLocation &Container,
793                        const PathDiagnosticLocation &Containee);
794
795  PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L);
796
797  PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L,
798                                         bool firstCharOnly = false) {
799    if (const Stmt *S = L.asStmt()) {
800      const Stmt *Original = S;
801      while (1) {
802        // Adjust the location for some expressions that are best referenced
803        // by one of their subexpressions.
804        switch (S->getStmtClass()) {
805          default:
806            break;
807          case Stmt::ParenExprClass:
808          case Stmt::GenericSelectionExprClass:
809            S = cast<Expr>(S)->IgnoreParens();
810            firstCharOnly = true;
811            continue;
812          case Stmt::BinaryConditionalOperatorClass:
813          case Stmt::ConditionalOperatorClass:
814            S = cast<AbstractConditionalOperator>(S)->getCond();
815            firstCharOnly = true;
816            continue;
817          case Stmt::ChooseExprClass:
818            S = cast<ChooseExpr>(S)->getCond();
819            firstCharOnly = true;
820            continue;
821          case Stmt::BinaryOperatorClass:
822            S = cast<BinaryOperator>(S)->getLHS();
823            firstCharOnly = true;
824            continue;
825        }
826
827        break;
828      }
829
830      if (S != Original)
831        L = PathDiagnosticLocation(S, L.getManager(), PDB.LC);
832    }
833
834    if (firstCharOnly)
835      L  = PathDiagnosticLocation::createSingleLocation(L);
836
837    return L;
838  }
839
840  void popLocation() {
841    if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) {
842      // For contexts, we only one the first character as the range.
843      rawAddEdge(cleanUpLocation(CLocs.back(), true));
844    }
845    CLocs.pop_back();
846  }
847
848public:
849  EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb)
850    : PD(pd), PDB(pdb) {
851
852      // If the PathDiagnostic already has pieces, add the enclosing statement
853      // of the first piece as a context as well.
854      if (!PD.path.empty()) {
855        PrevLoc = (*PD.path.begin())->getLocation();
856
857        if (const Stmt *S = PrevLoc.asStmt())
858          addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
859      }
860  }
861
862  ~EdgeBuilder() {
863    while (!CLocs.empty()) popLocation();
864
865    // Finally, add an initial edge from the start location of the first
866    // statement (if it doesn't already exist).
867    PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin(
868                                                       PDB.LC,
869                                                       PDB.getSourceManager());
870    if (L.isValid())
871      rawAddEdge(L);
872  }
873
874  void flushLocations() {
875    while (!CLocs.empty())
876      popLocation();
877    PrevLoc = PathDiagnosticLocation();
878  }
879
880  void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false);
881
882  void rawAddEdge(PathDiagnosticLocation NewLoc);
883
884  void addContext(const Stmt *S);
885  void addContext(const PathDiagnosticLocation &L);
886  void addExtendedContext(const Stmt *S);
887};
888} // end anonymous namespace
889
890
891PathDiagnosticLocation
892EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) {
893  if (const Stmt *S = L.asStmt()) {
894    if (IsControlFlowExpr(S))
895      return L;
896
897    return PDB.getEnclosingStmtLocation(S);
898  }
899
900  return L;
901}
902
903bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container,
904                                   const PathDiagnosticLocation &Containee) {
905
906  if (Container == Containee)
907    return true;
908
909  if (Container.asDecl())
910    return true;
911
912  if (const Stmt *S = Containee.asStmt())
913    if (const Stmt *ContainerS = Container.asStmt()) {
914      while (S) {
915        if (S == ContainerS)
916          return true;
917        S = PDB.getParent(S);
918      }
919      return false;
920    }
921
922  // Less accurate: compare using source ranges.
923  SourceRange ContainerR = Container.asRange();
924  SourceRange ContaineeR = Containee.asRange();
925
926  SourceManager &SM = PDB.getSourceManager();
927  SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin());
928  SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd());
929  SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin());
930  SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd());
931
932  unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg);
933  unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd);
934  unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg);
935  unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd);
936
937  assert(ContainerBegLine <= ContainerEndLine);
938  assert(ContaineeBegLine <= ContaineeEndLine);
939
940  return (ContainerBegLine <= ContaineeBegLine &&
941          ContainerEndLine >= ContaineeEndLine &&
942          (ContainerBegLine != ContaineeBegLine ||
943           SM.getExpansionColumnNumber(ContainerRBeg) <=
944           SM.getExpansionColumnNumber(ContaineeRBeg)) &&
945          (ContainerEndLine != ContaineeEndLine ||
946           SM.getExpansionColumnNumber(ContainerREnd) >=
947           SM.getExpansionColumnNumber(ContaineeREnd)));
948}
949
950void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) {
951  if (!PrevLoc.isValid()) {
952    PrevLoc = NewLoc;
953    return;
954  }
955
956  const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc);
957  const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc);
958
959  if (NewLocClean.asLocation() == PrevLocClean.asLocation())
960    return;
961
962  // FIXME: Ignore intra-macro edges for now.
963  if (NewLocClean.asLocation().getExpansionLoc() ==
964      PrevLocClean.asLocation().getExpansionLoc())
965    return;
966
967  PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean));
968  PrevLoc = NewLoc;
969}
970
971void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd) {
972
973  if (!alwaysAdd && NewLoc.asLocation().isMacroID())
974    return;
975
976  const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc);
977
978  while (!CLocs.empty()) {
979    ContextLocation &TopContextLoc = CLocs.back();
980
981    // Is the top location context the same as the one for the new location?
982    if (TopContextLoc == CLoc) {
983      if (alwaysAdd) {
984        if (IsConsumedExpr(TopContextLoc) &&
985            !IsControlFlowExpr(TopContextLoc.asStmt()))
986            TopContextLoc.markDead();
987
988        rawAddEdge(NewLoc);
989      }
990
991      return;
992    }
993
994    if (containsLocation(TopContextLoc, CLoc)) {
995      if (alwaysAdd) {
996        rawAddEdge(NewLoc);
997
998        if (IsConsumedExpr(CLoc) && !IsControlFlowExpr(CLoc.asStmt())) {
999          CLocs.push_back(ContextLocation(CLoc, true));
1000          return;
1001        }
1002      }
1003
1004      CLocs.push_back(CLoc);
1005      return;
1006    }
1007
1008    // Context does not contain the location.  Flush it.
1009    popLocation();
1010  }
1011
1012  // If we reach here, there is no enclosing context.  Just add the edge.
1013  rawAddEdge(NewLoc);
1014}
1015
1016bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) {
1017  if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt()))
1018    return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X);
1019
1020  return false;
1021}
1022
1023void EdgeBuilder::addExtendedContext(const Stmt *S) {
1024  if (!S)
1025    return;
1026
1027  const Stmt *Parent = PDB.getParent(S);
1028  while (Parent) {
1029    if (isa<CompoundStmt>(Parent))
1030      Parent = PDB.getParent(Parent);
1031    else
1032      break;
1033  }
1034
1035  if (Parent) {
1036    switch (Parent->getStmtClass()) {
1037      case Stmt::DoStmtClass:
1038      case Stmt::ObjCAtSynchronizedStmtClass:
1039        addContext(Parent);
1040      default:
1041        break;
1042    }
1043  }
1044
1045  addContext(S);
1046}
1047
1048void EdgeBuilder::addContext(const Stmt *S) {
1049  if (!S)
1050    return;
1051
1052  PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC);
1053  addContext(L);
1054}
1055
1056void EdgeBuilder::addContext(const PathDiagnosticLocation &L) {
1057  while (!CLocs.empty()) {
1058    const PathDiagnosticLocation &TopContextLoc = CLocs.back();
1059
1060    // Is the top location context the same as the one for the new location?
1061    if (TopContextLoc == L)
1062      return;
1063
1064    if (containsLocation(TopContextLoc, L)) {
1065      CLocs.push_back(L);
1066      return;
1067    }
1068
1069    // Context does not contain the location.  Flush it.
1070    popLocation();
1071  }
1072
1073  CLocs.push_back(L);
1074}
1075
1076// Cone-of-influence: support the reverse propagation of "interesting" symbols
1077// and values by tracing interesting calculations backwards through evaluated
1078// expressions along a path.  This is probably overly complicated, but the idea
1079// is that if an expression computed an "interesting" value, the child
1080// expressions are are also likely to be "interesting" as well (which then
1081// propagates to the values they in turn compute).  This reverse propagation
1082// is needed to track interesting correlations across function call boundaries,
1083// where formal arguments bind to actual arguments, etc.  This is also needed
1084// because the constraint solver sometimes simplifies certain symbolic values
1085// into constants when appropriate, and this complicates reasoning about
1086// interesting values.
1087typedef llvm::DenseSet<const Expr *> InterestingExprs;
1088
1089static void reversePropagateIntererstingSymbols(BugReport &R,
1090                                                InterestingExprs &IE,
1091                                                const ProgramState *State,
1092                                                const Expr *Ex,
1093                                                const LocationContext *LCtx) {
1094  SVal V = State->getSVal(Ex, LCtx);
1095  if (!(R.isInteresting(V) || IE.count(Ex)))
1096    return;
1097
1098  switch (Ex->getStmtClass()) {
1099    default:
1100      if (!isa<CastExpr>(Ex))
1101        break;
1102      // Fall through.
1103    case Stmt::BinaryOperatorClass:
1104    case Stmt::UnaryOperatorClass: {
1105      for (Stmt::const_child_iterator CI = Ex->child_begin(),
1106            CE = Ex->child_end();
1107            CI != CE; ++CI) {
1108        if (const Expr *child = dyn_cast_or_null<Expr>(*CI)) {
1109          IE.insert(child);
1110          SVal ChildV = State->getSVal(child, LCtx);
1111          R.markInteresting(ChildV);
1112        }
1113        break;
1114      }
1115    }
1116  }
1117
1118  R.markInteresting(V);
1119}
1120
1121static void reversePropagateInterestingSymbols(BugReport &R,
1122                                               InterestingExprs &IE,
1123                                               const ProgramState *State,
1124                                               const LocationContext *CalleeCtx,
1125                                               const LocationContext *CallerCtx)
1126{
1127  // FIXME: Handle non-CallExpr-based CallEvents.
1128  const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame();
1129  const Stmt *CallSite = Callee->getCallSite();
1130  if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) {
1131    if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) {
1132      FunctionDecl::param_const_iterator PI = FD->param_begin(),
1133                                         PE = FD->param_end();
1134      CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end();
1135      for (; AI != AE && PI != PE; ++AI, ++PI) {
1136        if (const Expr *ArgE = *AI) {
1137          if (const ParmVarDecl *PD = *PI) {
1138            Loc LV = State->getLValue(PD, CalleeCtx);
1139            if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV)))
1140              IE.insert(ArgE);
1141          }
1142        }
1143      }
1144    }
1145  }
1146}
1147
1148static void GenerateExtensivePathDiagnostic(PathDiagnostic& PD,
1149                                            PathDiagnosticBuilder &PDB,
1150                                            const ExplodedNode *N,
1151                                      ArrayRef<BugReporterVisitor *> visitors) {
1152  EdgeBuilder EB(PD, PDB);
1153  const SourceManager& SM = PDB.getSourceManager();
1154  StackDiagVector CallStack;
1155  InterestingExprs IE;
1156
1157  const ExplodedNode *NextNode = N->pred_empty() ? NULL : *(N->pred_begin());
1158  while (NextNode) {
1159    N = NextNode;
1160    NextNode = GetPredecessorNode(N);
1161    ProgramPoint P = N->getLocation();
1162
1163    do {
1164      if (const PostStmt *PS = dyn_cast<PostStmt>(&P)) {
1165        if (const Expr *Ex = PS->getStmtAs<Expr>())
1166          reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1167                                              N->getState().getPtr(), Ex,
1168                                              N->getLocationContext());
1169      }
1170
1171      if (const CallExitEnd *CE = dyn_cast<CallExitEnd>(&P)) {
1172        const Stmt *S = CE->getCalleeContext()->getCallSite();
1173        if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) {
1174            reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1175                                                N->getState().getPtr(), Ex,
1176                                                N->getLocationContext());
1177        }
1178
1179        PathDiagnosticCallPiece *C =
1180          PathDiagnosticCallPiece::construct(N, *CE, SM);
1181        GRBugReporter& BR = PDB.getBugReporter();
1182        BR.addCallPieceLocationContextPair(C, CE->getCalleeContext());
1183
1184        EB.addEdge(C->callReturn, true);
1185        EB.flushLocations();
1186
1187        PD.getActivePath().push_front(C);
1188        PD.pushActivePath(&C->path);
1189        CallStack.push_back(StackDiagPair(C, N));
1190        break;
1191      }
1192
1193      // Pop the call hierarchy if we are done walking the contents
1194      // of a function call.
1195      if (const CallEnter *CE = dyn_cast<CallEnter>(&P)) {
1196        // Add an edge to the start of the function.
1197        const Decl *D = CE->getCalleeContext()->getDecl();
1198        PathDiagnosticLocation pos =
1199          PathDiagnosticLocation::createBegin(D, SM);
1200        EB.addEdge(pos);
1201
1202        // Flush all locations, and pop the active path.
1203        bool VisitedEntireCall = PD.isWithinCall();
1204        EB.flushLocations();
1205        PD.popActivePath();
1206        PDB.LC = N->getLocationContext();
1207
1208        // Either we just added a bunch of stuff to the top-level path, or
1209        // we have a previous CallExitEnd.  If the former, it means that the
1210        // path terminated within a function call.  We must then take the
1211        // current contents of the active path and place it within
1212        // a new PathDiagnosticCallPiece.
1213        PathDiagnosticCallPiece *C;
1214        if (VisitedEntireCall) {
1215          C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
1216        } else {
1217          const Decl *Caller = CE->getLocationContext()->getDecl();
1218          C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
1219          GRBugReporter& BR = PDB.getBugReporter();
1220          BR.addCallPieceLocationContextPair(C, CE->getCalleeContext());
1221        }
1222
1223        C->setCallee(*CE, SM);
1224        EB.addContext(C->getLocation());
1225
1226        if (!CallStack.empty()) {
1227          assert(CallStack.back().first == C);
1228          CallStack.pop_back();
1229        }
1230        break;
1231      }
1232
1233      // Note that is important that we update the LocationContext
1234      // after looking at CallExits.  CallExit basically adds an
1235      // edge in the *caller*, so we don't want to update the LocationContext
1236      // too soon.
1237      PDB.LC = N->getLocationContext();
1238
1239      // Block edges.
1240      if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) {
1241        // Does this represent entering a call?  If so, look at propagating
1242        // interesting symbols across call boundaries.
1243        if (NextNode) {
1244          const LocationContext *CallerCtx = NextNode->getLocationContext();
1245          const LocationContext *CalleeCtx = PDB.LC;
1246          if (CallerCtx != CalleeCtx) {
1247            reversePropagateInterestingSymbols(*PDB.getBugReport(), IE,
1248                                               N->getState().getPtr(),
1249                                               CalleeCtx, CallerCtx);
1250          }
1251        }
1252
1253        const CFGBlock &Blk = *BE->getSrc();
1254        const Stmt *Term = Blk.getTerminator();
1255
1256        // Are we jumping to the head of a loop?  Add a special diagnostic.
1257        if (const Stmt *Loop = BE->getDst()->getLoopTarget()) {
1258          PathDiagnosticLocation L(Loop, SM, PDB.LC);
1259          const CompoundStmt *CS = NULL;
1260
1261          if (!Term) {
1262            if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
1263              CS = dyn_cast<CompoundStmt>(FS->getBody());
1264            else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
1265              CS = dyn_cast<CompoundStmt>(WS->getBody());
1266          }
1267
1268          PathDiagnosticEventPiece *p =
1269            new PathDiagnosticEventPiece(L,
1270                                        "Looping back to the head of the loop");
1271          p->setPrunable(true);
1272
1273          EB.addEdge(p->getLocation(), true);
1274          PD.getActivePath().push_front(p);
1275
1276          if (CS) {
1277            PathDiagnosticLocation BL =
1278              PathDiagnosticLocation::createEndBrace(CS, SM);
1279            EB.addEdge(BL);
1280          }
1281        }
1282
1283        if (Term)
1284          EB.addContext(Term);
1285
1286        break;
1287      }
1288
1289      if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) {
1290        if (const CFGStmt *S = BE->getFirstElement().getAs<CFGStmt>()) {
1291          const Stmt *stmt = S->getStmt();
1292          if (IsControlFlowExpr(stmt)) {
1293            // Add the proper context for '&&', '||', and '?'.
1294            EB.addContext(stmt);
1295          }
1296          else
1297            EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt());
1298        }
1299
1300        break;
1301      }
1302
1303
1304    } while (0);
1305
1306    if (!NextNode)
1307      continue;
1308
1309    // Add pieces from custom visitors.
1310    BugReport *R = PDB.getBugReport();
1311    for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(),
1312                                                  E = visitors.end();
1313         I != E; ++I) {
1314      if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) {
1315        const PathDiagnosticLocation &Loc = p->getLocation();
1316        EB.addEdge(Loc, true);
1317        PD.getActivePath().push_front(p);
1318        updateStackPiecesWithMessage(p, CallStack);
1319
1320        if (const Stmt *S = Loc.asStmt())
1321          EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
1322      }
1323    }
1324  }
1325}
1326
1327//===----------------------------------------------------------------------===//
1328// Methods for BugType and subclasses.
1329//===----------------------------------------------------------------------===//
1330BugType::~BugType() { }
1331
1332void BugType::FlushReports(BugReporter &BR) {}
1333
1334void BuiltinBug::anchor() {}
1335
1336//===----------------------------------------------------------------------===//
1337// Methods for BugReport and subclasses.
1338//===----------------------------------------------------------------------===//
1339
1340void BugReport::NodeResolver::anchor() {}
1341
1342void BugReport::addVisitor(BugReporterVisitor* visitor) {
1343  if (!visitor)
1344    return;
1345
1346  llvm::FoldingSetNodeID ID;
1347  visitor->Profile(ID);
1348  void *InsertPos;
1349
1350  if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) {
1351    delete visitor;
1352    return;
1353  }
1354
1355  CallbacksSet.InsertNode(visitor, InsertPos);
1356  Callbacks.push_back(visitor);
1357  ++ConfigurationChangeToken;
1358}
1359
1360BugReport::~BugReport() {
1361  for (visitor_iterator I = visitor_begin(), E = visitor_end(); I != E; ++I) {
1362    delete *I;
1363  }
1364  while (!interestingSymbols.empty()) {
1365    popInterestingSymbolsAndRegions();
1366  }
1367}
1368
1369const Decl *BugReport::getDeclWithIssue() const {
1370  if (DeclWithIssue)
1371    return DeclWithIssue;
1372
1373  const ExplodedNode *N = getErrorNode();
1374  if (!N)
1375    return 0;
1376
1377  const LocationContext *LC = N->getLocationContext();
1378  return LC->getCurrentStackFrame()->getDecl();
1379}
1380
1381void BugReport::Profile(llvm::FoldingSetNodeID& hash) const {
1382  hash.AddPointer(&BT);
1383  hash.AddString(Description);
1384  if (UniqueingLocation.isValid()) {
1385    UniqueingLocation.Profile(hash);
1386  } else if (Location.isValid()) {
1387    Location.Profile(hash);
1388  } else {
1389    assert(ErrorNode);
1390    hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode));
1391  }
1392
1393  for (SmallVectorImpl<SourceRange>::const_iterator I =
1394      Ranges.begin(), E = Ranges.end(); I != E; ++I) {
1395    const SourceRange range = *I;
1396    if (!range.isValid())
1397      continue;
1398    hash.AddInteger(range.getBegin().getRawEncoding());
1399    hash.AddInteger(range.getEnd().getRawEncoding());
1400  }
1401}
1402
1403void BugReport::markInteresting(SymbolRef sym) {
1404  if (!sym)
1405    return;
1406
1407  // If the symbol wasn't already in our set, note a configuration change.
1408  if (getInterestingSymbols().insert(sym).second)
1409    ++ConfigurationChangeToken;
1410
1411  if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym))
1412    getInterestingRegions().insert(meta->getRegion());
1413}
1414
1415void BugReport::markInteresting(const MemRegion *R) {
1416  if (!R)
1417    return;
1418
1419  // If the base region wasn't already in our set, note a configuration change.
1420  R = R->getBaseRegion();
1421  if (getInterestingRegions().insert(R).second)
1422    ++ConfigurationChangeToken;
1423
1424  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1425    getInterestingSymbols().insert(SR->getSymbol());
1426}
1427
1428void BugReport::markInteresting(SVal V) {
1429  markInteresting(V.getAsRegion());
1430  markInteresting(V.getAsSymbol());
1431}
1432
1433void BugReport::markInteresting(const LocationContext *LC) {
1434  if (!LC)
1435    return;
1436  InterestingLocationContexts.insert(LC);
1437}
1438
1439bool BugReport::isInteresting(SVal V) {
1440  return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol());
1441}
1442
1443bool BugReport::isInteresting(SymbolRef sym) {
1444  if (!sym)
1445    return false;
1446  // We don't currently consider metadata symbols to be interesting
1447  // even if we know their region is interesting. Is that correct behavior?
1448  return getInterestingSymbols().count(sym);
1449}
1450
1451bool BugReport::isInteresting(const MemRegion *R) {
1452  if (!R)
1453    return false;
1454  R = R->getBaseRegion();
1455  bool b = getInterestingRegions().count(R);
1456  if (b)
1457    return true;
1458  if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
1459    return getInterestingSymbols().count(SR->getSymbol());
1460  return false;
1461}
1462
1463bool BugReport::isInteresting(const LocationContext *LC) {
1464  if (!LC)
1465    return false;
1466  return InterestingLocationContexts.count(LC);
1467}
1468
1469void BugReport::lazyInitializeInterestingSets() {
1470  if (interestingSymbols.empty()) {
1471    interestingSymbols.push_back(new Symbols());
1472    interestingRegions.push_back(new Regions());
1473  }
1474}
1475
1476BugReport::Symbols &BugReport::getInterestingSymbols() {
1477  lazyInitializeInterestingSets();
1478  return *interestingSymbols.back();
1479}
1480
1481BugReport::Regions &BugReport::getInterestingRegions() {
1482  lazyInitializeInterestingSets();
1483  return *interestingRegions.back();
1484}
1485
1486void BugReport::pushInterestingSymbolsAndRegions() {
1487  interestingSymbols.push_back(new Symbols(getInterestingSymbols()));
1488  interestingRegions.push_back(new Regions(getInterestingRegions()));
1489}
1490
1491void BugReport::popInterestingSymbolsAndRegions() {
1492  delete interestingSymbols.back();
1493  interestingSymbols.pop_back();
1494  delete interestingRegions.back();
1495  interestingRegions.pop_back();
1496}
1497
1498const Stmt *BugReport::getStmt() const {
1499  if (!ErrorNode)
1500    return 0;
1501
1502  ProgramPoint ProgP = ErrorNode->getLocation();
1503  const Stmt *S = NULL;
1504
1505  if (BlockEntrance *BE = dyn_cast<BlockEntrance>(&ProgP)) {
1506    CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit();
1507    if (BE->getBlock() == &Exit)
1508      S = GetPreviousStmt(ErrorNode);
1509  }
1510  if (!S)
1511    S = GetStmt(ProgP);
1512
1513  return S;
1514}
1515
1516std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator>
1517BugReport::getRanges() {
1518    // If no custom ranges, add the range of the statement corresponding to
1519    // the error node.
1520    if (Ranges.empty()) {
1521      if (const Expr *E = dyn_cast_or_null<Expr>(getStmt()))
1522        addRange(E->getSourceRange());
1523      else
1524        return std::make_pair(ranges_iterator(), ranges_iterator());
1525    }
1526
1527    // User-specified absence of range info.
1528    if (Ranges.size() == 1 && !Ranges.begin()->isValid())
1529      return std::make_pair(ranges_iterator(), ranges_iterator());
1530
1531    return std::make_pair(Ranges.begin(), Ranges.end());
1532}
1533
1534PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const {
1535  if (ErrorNode) {
1536    assert(!Location.isValid() &&
1537     "Either Location or ErrorNode should be specified but not both.");
1538
1539    if (const Stmt *S = GetCurrentOrPreviousStmt(ErrorNode)) {
1540      const LocationContext *LC = ErrorNode->getLocationContext();
1541
1542      // For member expressions, return the location of the '.' or '->'.
1543      if (const MemberExpr *ME = dyn_cast<MemberExpr>(S))
1544        return PathDiagnosticLocation::createMemberLoc(ME, SM);
1545      // For binary operators, return the location of the operator.
1546      if (const BinaryOperator *B = dyn_cast<BinaryOperator>(S))
1547        return PathDiagnosticLocation::createOperatorLoc(B, SM);
1548
1549      return PathDiagnosticLocation::createBegin(S, SM, LC);
1550    }
1551  } else {
1552    assert(Location.isValid());
1553    return Location;
1554  }
1555
1556  return PathDiagnosticLocation();
1557}
1558
1559//===----------------------------------------------------------------------===//
1560// Methods for BugReporter and subclasses.
1561//===----------------------------------------------------------------------===//
1562
1563BugReportEquivClass::~BugReportEquivClass() { }
1564GRBugReporter::~GRBugReporter() { }
1565BugReporterData::~BugReporterData() {}
1566
1567ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); }
1568
1569ProgramStateManager&
1570GRBugReporter::getStateManager() { return Eng.getStateManager(); }
1571
1572BugReporter::~BugReporter() {
1573  FlushReports();
1574
1575  // Free the bug reports we are tracking.
1576  typedef std::vector<BugReportEquivClass *> ContTy;
1577  for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end();
1578       I != E; ++I) {
1579    delete *I;
1580  }
1581}
1582
1583void BugReporter::FlushReports() {
1584  if (BugTypes.isEmpty())
1585    return;
1586
1587  // First flush the warnings for each BugType.  This may end up creating new
1588  // warnings and new BugTypes.
1589  // FIXME: Only NSErrorChecker needs BugType's FlushReports.
1590  // Turn NSErrorChecker into a proper checker and remove this.
1591  SmallVector<const BugType*, 16> bugTypes;
1592  for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I)
1593    bugTypes.push_back(*I);
1594  for (SmallVector<const BugType*, 16>::iterator
1595         I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I)
1596    const_cast<BugType*>(*I)->FlushReports(*this);
1597
1598  // We need to flush reports in deterministic order to ensure the order
1599  // of the reports is consistent between runs.
1600  typedef std::vector<BugReportEquivClass *> ContVecTy;
1601  for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end();
1602       EI != EE; ++EI){
1603    BugReportEquivClass& EQ = **EI;
1604    FlushReport(EQ);
1605  }
1606
1607  // BugReporter owns and deletes only BugTypes created implicitly through
1608  // EmitBasicReport.
1609  // FIXME: There are leaks from checkers that assume that the BugTypes they
1610  // create will be destroyed by the BugReporter.
1611  for (llvm::StringMap<BugType*>::iterator
1612         I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I)
1613    delete I->second;
1614
1615  // Remove all references to the BugType objects.
1616  BugTypes = F.getEmptySet();
1617}
1618
1619//===----------------------------------------------------------------------===//
1620// PathDiagnostics generation.
1621//===----------------------------------------------------------------------===//
1622
1623static std::pair<std::pair<ExplodedGraph*, NodeBackMap*>,
1624                 std::pair<ExplodedNode*, unsigned> >
1625MakeReportGraph(const ExplodedGraph* G,
1626                SmallVectorImpl<const ExplodedNode*> &nodes) {
1627
1628  // Create the trimmed graph.  It will contain the shortest paths from the
1629  // error nodes to the root.  In the new graph we should only have one
1630  // error node unless there are two or more error nodes with the same minimum
1631  // path length.
1632  ExplodedGraph* GTrim;
1633  InterExplodedGraphMap* NMap;
1634
1635  llvm::DenseMap<const void*, const void*> InverseMap;
1636  llvm::tie(GTrim, NMap) = G->Trim(nodes.data(), nodes.data() + nodes.size(),
1637                                   &InverseMap);
1638
1639  // Create owning pointers for GTrim and NMap just to ensure that they are
1640  // released when this function exists.
1641  OwningPtr<ExplodedGraph> AutoReleaseGTrim(GTrim);
1642  OwningPtr<InterExplodedGraphMap> AutoReleaseNMap(NMap);
1643
1644  // Find the (first) error node in the trimmed graph.  We just need to consult
1645  // the node map (NMap) which maps from nodes in the original graph to nodes
1646  // in the new graph.
1647
1648  std::queue<const ExplodedNode*> WS;
1649  typedef llvm::DenseMap<const ExplodedNode*, unsigned> IndexMapTy;
1650  IndexMapTy IndexMap;
1651
1652  for (unsigned nodeIndex = 0 ; nodeIndex < nodes.size(); ++nodeIndex) {
1653    const ExplodedNode *originalNode = nodes[nodeIndex];
1654    if (const ExplodedNode *N = NMap->getMappedNode(originalNode)) {
1655      WS.push(N);
1656      IndexMap[originalNode] = nodeIndex;
1657    }
1658  }
1659
1660  assert(!WS.empty() && "No error node found in the trimmed graph.");
1661
1662  // Create a new (third!) graph with a single path.  This is the graph
1663  // that will be returned to the caller.
1664  ExplodedGraph *GNew = new ExplodedGraph();
1665
1666  // Sometimes the trimmed graph can contain a cycle.  Perform a reverse BFS
1667  // to the root node, and then construct a new graph that contains only
1668  // a single path.
1669  llvm::DenseMap<const void*,unsigned> Visited;
1670
1671  unsigned cnt = 0;
1672  const ExplodedNode *Root = 0;
1673
1674  while (!WS.empty()) {
1675    const ExplodedNode *Node = WS.front();
1676    WS.pop();
1677
1678    if (Visited.find(Node) != Visited.end())
1679      continue;
1680
1681    Visited[Node] = cnt++;
1682
1683    if (Node->pred_empty()) {
1684      Root = Node;
1685      break;
1686    }
1687
1688    for (ExplodedNode::const_pred_iterator I=Node->pred_begin(),
1689         E=Node->pred_end(); I!=E; ++I)
1690      WS.push(*I);
1691  }
1692
1693  assert(Root);
1694
1695  // Now walk from the root down the BFS path, always taking the successor
1696  // with the lowest number.
1697  ExplodedNode *Last = 0, *First = 0;
1698  NodeBackMap *BM = new NodeBackMap();
1699  unsigned NodeIndex = 0;
1700
1701  for ( const ExplodedNode *N = Root ;;) {
1702    // Lookup the number associated with the current node.
1703    llvm::DenseMap<const void*,unsigned>::iterator I = Visited.find(N);
1704    assert(I != Visited.end());
1705
1706    // Create the equivalent node in the new graph with the same state
1707    // and location.
1708    ExplodedNode *NewN = GNew->getNode(N->getLocation(), N->getState());
1709
1710    // Store the mapping to the original node.
1711    llvm::DenseMap<const void*, const void*>::iterator IMitr=InverseMap.find(N);
1712    assert(IMitr != InverseMap.end() && "No mapping to original node.");
1713    (*BM)[NewN] = (const ExplodedNode*) IMitr->second;
1714
1715    // Link up the new node with the previous node.
1716    if (Last)
1717      NewN->addPredecessor(Last, *GNew);
1718
1719    Last = NewN;
1720
1721    // Are we at the final node?
1722    IndexMapTy::iterator IMI =
1723      IndexMap.find((const ExplodedNode*)(IMitr->second));
1724    if (IMI != IndexMap.end()) {
1725      First = NewN;
1726      NodeIndex = IMI->second;
1727      break;
1728    }
1729
1730    // Find the next successor node.  We choose the node that is marked
1731    // with the lowest DFS number.
1732    ExplodedNode::const_succ_iterator SI = N->succ_begin();
1733    ExplodedNode::const_succ_iterator SE = N->succ_end();
1734    N = 0;
1735
1736    for (unsigned MinVal = 0; SI != SE; ++SI) {
1737
1738      I = Visited.find(*SI);
1739
1740      if (I == Visited.end())
1741        continue;
1742
1743      if (!N || I->second < MinVal) {
1744        N = *SI;
1745        MinVal = I->second;
1746      }
1747    }
1748
1749    assert(N);
1750  }
1751
1752  assert(First);
1753
1754  return std::make_pair(std::make_pair(GNew, BM),
1755                        std::make_pair(First, NodeIndex));
1756}
1757
1758/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object
1759///  and collapses PathDiagosticPieces that are expanded by macros.
1760static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) {
1761  typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>,
1762                                SourceLocation> > MacroStackTy;
1763
1764  typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> >
1765          PiecesTy;
1766
1767  MacroStackTy MacroStack;
1768  PiecesTy Pieces;
1769
1770  for (PathPieces::const_iterator I = path.begin(), E = path.end();
1771       I!=E; ++I) {
1772
1773    PathDiagnosticPiece *piece = I->getPtr();
1774
1775    // Recursively compact calls.
1776    if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){
1777      CompactPathDiagnostic(call->path, SM);
1778    }
1779
1780    // Get the location of the PathDiagnosticPiece.
1781    const FullSourceLoc Loc = piece->getLocation().asLocation();
1782
1783    // Determine the instantiation location, which is the location we group
1784    // related PathDiagnosticPieces.
1785    SourceLocation InstantiationLoc = Loc.isMacroID() ?
1786                                      SM.getExpansionLoc(Loc) :
1787                                      SourceLocation();
1788
1789    if (Loc.isFileID()) {
1790      MacroStack.clear();
1791      Pieces.push_back(piece);
1792      continue;
1793    }
1794
1795    assert(Loc.isMacroID());
1796
1797    // Is the PathDiagnosticPiece within the same macro group?
1798    if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) {
1799      MacroStack.back().first->subPieces.push_back(piece);
1800      continue;
1801    }
1802
1803    // We aren't in the same group.  Are we descending into a new macro
1804    // or are part of an old one?
1805    IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup;
1806
1807    SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ?
1808                                          SM.getExpansionLoc(Loc) :
1809                                          SourceLocation();
1810
1811    // Walk the entire macro stack.
1812    while (!MacroStack.empty()) {
1813      if (InstantiationLoc == MacroStack.back().second) {
1814        MacroGroup = MacroStack.back().first;
1815        break;
1816      }
1817
1818      if (ParentInstantiationLoc == MacroStack.back().second) {
1819        MacroGroup = MacroStack.back().first;
1820        break;
1821      }
1822
1823      MacroStack.pop_back();
1824    }
1825
1826    if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) {
1827      // Create a new macro group and add it to the stack.
1828      PathDiagnosticMacroPiece *NewGroup =
1829        new PathDiagnosticMacroPiece(
1830          PathDiagnosticLocation::createSingleLocation(piece->getLocation()));
1831
1832      if (MacroGroup)
1833        MacroGroup->subPieces.push_back(NewGroup);
1834      else {
1835        assert(InstantiationLoc.isFileID());
1836        Pieces.push_back(NewGroup);
1837      }
1838
1839      MacroGroup = NewGroup;
1840      MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc));
1841    }
1842
1843    // Finally, add the PathDiagnosticPiece to the group.
1844    MacroGroup->subPieces.push_back(piece);
1845  }
1846
1847  // Now take the pieces and construct a new PathDiagnostic.
1848  path.clear();
1849
1850  for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I)
1851    path.push_back(*I);
1852}
1853
1854void GRBugReporter::GeneratePathDiagnostic(PathDiagnostic& PD,
1855                                           PathDiagnosticConsumer &PC,
1856                                           ArrayRef<BugReport *> &bugReports) {
1857
1858  assert(!bugReports.empty());
1859  SmallVector<const ExplodedNode *, 10> errorNodes;
1860  for (ArrayRef<BugReport*>::iterator I = bugReports.begin(),
1861                                      E = bugReports.end(); I != E; ++I) {
1862      errorNodes.push_back((*I)->getErrorNode());
1863  }
1864
1865  // Construct a new graph that contains only a single path from the error
1866  // node to a root.
1867  const std::pair<std::pair<ExplodedGraph*, NodeBackMap*>,
1868  std::pair<ExplodedNode*, unsigned> >&
1869    GPair = MakeReportGraph(&getGraph(), errorNodes);
1870
1871  // Find the BugReport with the original location.
1872  assert(GPair.second.second < bugReports.size());
1873  BugReport *R = bugReports[GPair.second.second];
1874  assert(R && "No original report found for sliced graph.");
1875
1876  OwningPtr<ExplodedGraph> ReportGraph(GPair.first.first);
1877  OwningPtr<NodeBackMap> BackMap(GPair.first.second);
1878  const ExplodedNode *N = GPair.second.first;
1879
1880  // Start building the path diagnostic...
1881  PathDiagnosticBuilder PDB(*this, R, BackMap.get(), &PC);
1882
1883  // Register additional node visitors.
1884  R->addVisitor(new NilReceiverBRVisitor());
1885  R->addVisitor(new ConditionBRVisitor());
1886
1887  BugReport::VisitorList visitors;
1888  unsigned originalReportConfigToken, finalReportConfigToken;
1889
1890  // While generating diagnostics, it's possible the visitors will decide
1891  // new symbols and regions are interesting, or add other visitors based on
1892  // the information they find. If they do, we need to regenerate the path
1893  // based on our new report configuration.
1894  do {
1895    // Get a clean copy of all the visitors.
1896    for (BugReport::visitor_iterator I = R->visitor_begin(),
1897                                     E = R->visitor_end(); I != E; ++I)
1898       visitors.push_back((*I)->clone());
1899
1900    // Clear out the active path from any previous work.
1901    PD.resetPath();
1902    originalReportConfigToken = R->getConfigurationChangeToken();
1903
1904    // Generate the very last diagnostic piece - the piece is visible before
1905    // the trace is expanded.
1906    PathDiagnosticPiece *LastPiece = 0;
1907    for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end();
1908         I != E; ++I) {
1909      if (PathDiagnosticPiece *Piece = (*I)->getEndPath(PDB, N, *R)) {
1910        assert (!LastPiece &&
1911                "There can only be one final piece in a diagnostic.");
1912        LastPiece = Piece;
1913      }
1914    }
1915    if (!LastPiece)
1916      LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R);
1917    if (LastPiece)
1918      PD.setEndOfPath(LastPiece);
1919    else
1920      return;
1921
1922    switch (PDB.getGenerationScheme()) {
1923    case PathDiagnosticConsumer::Extensive:
1924      GenerateExtensivePathDiagnostic(PD, PDB, N, visitors);
1925      break;
1926    case PathDiagnosticConsumer::Minimal:
1927      GenerateMinimalPathDiagnostic(PD, PDB, N, visitors);
1928      break;
1929    case PathDiagnosticConsumer::None:
1930      llvm_unreachable("PathDiagnosticConsumer::None should never appear here");
1931    }
1932
1933    // Clean up the visitors we used.
1934    llvm::DeleteContainerPointers(visitors);
1935
1936    // Did anything change while generating this path?
1937    finalReportConfigToken = R->getConfigurationChangeToken();
1938  } while(finalReportConfigToken != originalReportConfigToken);
1939
1940  // Finally, prune the diagnostic path of uninteresting stuff.
1941  if (R->shouldPrunePath()) {
1942    bool hasSomethingInteresting = RemoveUneededCalls(PD.getMutablePieces(), R);
1943    assert(hasSomethingInteresting);
1944    (void) hasSomethingInteresting;
1945  }
1946}
1947
1948void BugReporter::Register(BugType *BT) {
1949  BugTypes = F.add(BugTypes, BT);
1950}
1951
1952void BugReporter::EmitReport(BugReport* R) {
1953  // Compute the bug report's hash to determine its equivalence class.
1954  llvm::FoldingSetNodeID ID;
1955  R->Profile(ID);
1956
1957  // Lookup the equivance class.  If there isn't one, create it.
1958  BugType& BT = R->getBugType();
1959  Register(&BT);
1960  void *InsertPos;
1961  BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos);
1962
1963  if (!EQ) {
1964    EQ = new BugReportEquivClass(R);
1965    EQClasses.InsertNode(EQ, InsertPos);
1966    EQClassesVector.push_back(EQ);
1967  }
1968  else
1969    EQ->AddReport(R);
1970}
1971
1972
1973//===----------------------------------------------------------------------===//
1974// Emitting reports in equivalence classes.
1975//===----------------------------------------------------------------------===//
1976
1977namespace {
1978struct FRIEC_WLItem {
1979  const ExplodedNode *N;
1980  ExplodedNode::const_succ_iterator I, E;
1981
1982  FRIEC_WLItem(const ExplodedNode *n)
1983  : N(n), I(N->succ_begin()), E(N->succ_end()) {}
1984};
1985}
1986
1987static BugReport *
1988FindReportInEquivalenceClass(BugReportEquivClass& EQ,
1989                             SmallVectorImpl<BugReport*> &bugReports) {
1990
1991  BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end();
1992  assert(I != E);
1993  BugType& BT = I->getBugType();
1994
1995  // If we don't need to suppress any of the nodes because they are
1996  // post-dominated by a sink, simply add all the nodes in the equivalence class
1997  // to 'Nodes'.  Any of the reports will serve as a "representative" report.
1998  if (!BT.isSuppressOnSink()) {
1999    BugReport *R = I;
2000    for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) {
2001      const ExplodedNode *N = I->getErrorNode();
2002      if (N) {
2003        R = I;
2004        bugReports.push_back(R);
2005      }
2006    }
2007    return R;
2008  }
2009
2010  // For bug reports that should be suppressed when all paths are post-dominated
2011  // by a sink node, iterate through the reports in the equivalence class
2012  // until we find one that isn't post-dominated (if one exists).  We use a
2013  // DFS traversal of the ExplodedGraph to find a non-sink node.  We could write
2014  // this as a recursive function, but we don't want to risk blowing out the
2015  // stack for very long paths.
2016  BugReport *exampleReport = 0;
2017
2018  for (; I != E; ++I) {
2019    const ExplodedNode *errorNode = I->getErrorNode();
2020
2021    if (!errorNode)
2022      continue;
2023    if (errorNode->isSink()) {
2024      llvm_unreachable(
2025           "BugType::isSuppressSink() should not be 'true' for sink end nodes");
2026    }
2027    // No successors?  By definition this nodes isn't post-dominated by a sink.
2028    if (errorNode->succ_empty()) {
2029      bugReports.push_back(I);
2030      if (!exampleReport)
2031        exampleReport = I;
2032      continue;
2033    }
2034
2035    // At this point we know that 'N' is not a sink and it has at least one
2036    // successor.  Use a DFS worklist to find a non-sink end-of-path node.
2037    typedef FRIEC_WLItem WLItem;
2038    typedef SmallVector<WLItem, 10> DFSWorkList;
2039    llvm::DenseMap<const ExplodedNode *, unsigned> Visited;
2040
2041    DFSWorkList WL;
2042    WL.push_back(errorNode);
2043    Visited[errorNode] = 1;
2044
2045    while (!WL.empty()) {
2046      WLItem &WI = WL.back();
2047      assert(!WI.N->succ_empty());
2048
2049      for (; WI.I != WI.E; ++WI.I) {
2050        const ExplodedNode *Succ = *WI.I;
2051        // End-of-path node?
2052        if (Succ->succ_empty()) {
2053          // If we found an end-of-path node that is not a sink.
2054          if (!Succ->isSink()) {
2055            bugReports.push_back(I);
2056            if (!exampleReport)
2057              exampleReport = I;
2058            WL.clear();
2059            break;
2060          }
2061          // Found a sink?  Continue on to the next successor.
2062          continue;
2063        }
2064        // Mark the successor as visited.  If it hasn't been explored,
2065        // enqueue it to the DFS worklist.
2066        unsigned &mark = Visited[Succ];
2067        if (!mark) {
2068          mark = 1;
2069          WL.push_back(Succ);
2070          break;
2071        }
2072      }
2073
2074      // The worklist may have been cleared at this point.  First
2075      // check if it is empty before checking the last item.
2076      if (!WL.empty() && &WL.back() == &WI)
2077        WL.pop_back();
2078    }
2079  }
2080
2081  // ExampleReport will be NULL if all the nodes in the equivalence class
2082  // were post-dominated by sinks.
2083  return exampleReport;
2084}
2085
2086void BugReporter::FlushReport(BugReportEquivClass& EQ) {
2087  SmallVector<BugReport*, 10> bugReports;
2088  BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports);
2089  if (exampleReport) {
2090    const PathDiagnosticConsumers &C = getPathDiagnosticConsumers();
2091    for (PathDiagnosticConsumers::const_iterator I=C.begin(),
2092                                                 E=C.end(); I != E; ++I) {
2093      FlushReport(exampleReport, **I, bugReports);
2094    }
2095  }
2096}
2097
2098void BugReporter::FlushReport(BugReport *exampleReport,
2099                              PathDiagnosticConsumer &PD,
2100                              ArrayRef<BugReport*> bugReports) {
2101
2102  // FIXME: Make sure we use the 'R' for the path that was actually used.
2103  // Probably doesn't make a difference in practice.
2104  BugType& BT = exampleReport->getBugType();
2105
2106  OwningPtr<PathDiagnostic>
2107    D(new PathDiagnostic(exampleReport->getDeclWithIssue(),
2108                         exampleReport->getBugType().getName(),
2109                         exampleReport->getDescription(),
2110                         exampleReport->getShortDescription(/*Fallback=*/false),
2111                         BT.getCategory()));
2112
2113  // Generate the full path diagnostic, using the generation scheme
2114  // specified by the PathDiagnosticConsumer.
2115  if (PD.getGenerationScheme() != PathDiagnosticConsumer::None) {
2116    if (!bugReports.empty())
2117      GeneratePathDiagnostic(*D.get(), PD, bugReports);
2118  }
2119
2120  // If the path is empty, generate a single step path with the location
2121  // of the issue.
2122  if (D->path.empty()) {
2123    PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager());
2124    PathDiagnosticPiece *piece =
2125      new PathDiagnosticEventPiece(L, exampleReport->getDescription());
2126    BugReport::ranges_iterator Beg, End;
2127    llvm::tie(Beg, End) = exampleReport->getRanges();
2128    for ( ; Beg != End; ++Beg)
2129      piece->addRange(*Beg);
2130    D->setEndOfPath(piece);
2131  }
2132
2133  // Get the meta data.
2134  const BugReport::ExtraTextList &Meta = exampleReport->getExtraText();
2135  for (BugReport::ExtraTextList::const_iterator i = Meta.begin(),
2136                                                e = Meta.end(); i != e; ++i) {
2137    D->addMeta(*i);
2138  }
2139
2140  PD.HandlePathDiagnostic(D.take());
2141}
2142
2143void BugReporter::EmitBasicReport(const Decl *DeclWithIssue,
2144                                  StringRef name,
2145                                  StringRef category,
2146                                  StringRef str, PathDiagnosticLocation Loc,
2147                                  SourceRange* RBeg, unsigned NumRanges) {
2148
2149  // 'BT' is owned by BugReporter.
2150  BugType *BT = getBugTypeForName(name, category);
2151  BugReport *R = new BugReport(*BT, str, Loc);
2152  R->setDeclWithIssue(DeclWithIssue);
2153  for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg);
2154  EmitReport(R);
2155}
2156
2157BugType *BugReporter::getBugTypeForName(StringRef name,
2158                                        StringRef category) {
2159  SmallString<136> fullDesc;
2160  llvm::raw_svector_ostream(fullDesc) << name << ":" << category;
2161  llvm::StringMapEntry<BugType *> &
2162      entry = StrBugTypes.GetOrCreateValue(fullDesc);
2163  BugType *BT = entry.getValue();
2164  if (!BT) {
2165    BT = new BugType(name, category);
2166    entry.setValue(BT);
2167  }
2168  return BT;
2169}
2170