• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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/AST/ASTContext.h"
17 #include "clang/AST/DeclObjC.h"
18 #include "clang/AST/Expr.h"
19 #include "clang/AST/ExprCXX.h"
20 #include "clang/AST/ParentMap.h"
21 #include "clang/AST/StmtCXX.h"
22 #include "clang/AST/StmtObjC.h"
23 #include "clang/Analysis/CFG.h"
24 #include "clang/Analysis/ProgramPoint.h"
25 #include "clang/Basic/SourceManager.h"
26 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
27 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
28 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
29 #include "llvm/ADT/DenseMap.h"
30 #include "llvm/ADT/IntrusiveRefCntPtr.h"
31 #include "llvm/ADT/STLExtras.h"
32 #include "llvm/ADT/SmallString.h"
33 #include "llvm/ADT/Statistic.h"
34 #include "llvm/Support/raw_ostream.h"
35 #include <memory>
36 #include <queue>
37 
38 using namespace clang;
39 using namespace ento;
40 
41 #define DEBUG_TYPE "BugReporter"
42 
43 STATISTIC(MaxBugClassSize,
44           "The maximum number of bug reports in the same equivalence class");
45 STATISTIC(MaxValidBugClassSize,
46           "The maximum number of bug reports in the same equivalence class "
47           "where at least one report is valid (not suppressed)");
48 
~BugReporterVisitor()49 BugReporterVisitor::~BugReporterVisitor() {}
50 
anchor()51 void BugReporterContext::anchor() {}
52 
53 //===----------------------------------------------------------------------===//
54 // Helper routines for walking the ExplodedGraph and fetching statements.
55 //===----------------------------------------------------------------------===//
56 
GetPreviousStmt(const ExplodedNode * N)57 static const Stmt *GetPreviousStmt(const ExplodedNode *N) {
58   for (N = N->getFirstPred(); N; N = N->getFirstPred())
59     if (const Stmt *S = PathDiagnosticLocation::getStmt(N))
60       return S;
61 
62   return nullptr;
63 }
64 
65 static inline const Stmt*
GetCurrentOrPreviousStmt(const ExplodedNode * N)66 GetCurrentOrPreviousStmt(const ExplodedNode *N) {
67   if (const Stmt *S = PathDiagnosticLocation::getStmt(N))
68     return S;
69 
70   return GetPreviousStmt(N);
71 }
72 
73 //===----------------------------------------------------------------------===//
74 // Diagnostic cleanup.
75 //===----------------------------------------------------------------------===//
76 
77 static PathDiagnosticEventPiece *
eventsDescribeSameCondition(PathDiagnosticEventPiece * X,PathDiagnosticEventPiece * Y)78 eventsDescribeSameCondition(PathDiagnosticEventPiece *X,
79                             PathDiagnosticEventPiece *Y) {
80   // Prefer diagnostics that come from ConditionBRVisitor over
81   // those that came from TrackConstraintBRVisitor.
82   const void *tagPreferred = ConditionBRVisitor::getTag();
83   const void *tagLesser = TrackConstraintBRVisitor::getTag();
84 
85   if (X->getLocation() != Y->getLocation())
86     return nullptr;
87 
88   if (X->getTag() == tagPreferred && Y->getTag() == tagLesser)
89     return X;
90 
91   if (Y->getTag() == tagPreferred && X->getTag() == tagLesser)
92     return Y;
93 
94   return nullptr;
95 }
96 
97 /// An optimization pass over PathPieces that removes redundant diagnostics
98 /// generated by both ConditionBRVisitor and TrackConstraintBRVisitor.  Both
99 /// BugReporterVisitors use different methods to generate diagnostics, with
100 /// one capable of emitting diagnostics in some cases but not in others.  This
101 /// can lead to redundant diagnostic pieces at the same point in a path.
removeRedundantMsgs(PathPieces & path)102 static void removeRedundantMsgs(PathPieces &path) {
103   unsigned N = path.size();
104   if (N < 2)
105     return;
106   // NOTE: this loop intentionally is not using an iterator.  Instead, we
107   // are streaming the path and modifying it in place.  This is done by
108   // grabbing the front, processing it, and if we decide to keep it append
109   // it to the end of the path.  The entire path is processed in this way.
110   for (unsigned i = 0; i < N; ++i) {
111     IntrusiveRefCntPtr<PathDiagnosticPiece> piece(path.front());
112     path.pop_front();
113 
114     switch (piece->getKind()) {
115       case clang::ento::PathDiagnosticPiece::Call:
116         removeRedundantMsgs(cast<PathDiagnosticCallPiece>(piece)->path);
117         break;
118       case clang::ento::PathDiagnosticPiece::Macro:
119         removeRedundantMsgs(cast<PathDiagnosticMacroPiece>(piece)->subPieces);
120         break;
121       case clang::ento::PathDiagnosticPiece::ControlFlow:
122         break;
123       case clang::ento::PathDiagnosticPiece::Event: {
124         if (i == N-1)
125           break;
126 
127         if (PathDiagnosticEventPiece *nextEvent =
128             dyn_cast<PathDiagnosticEventPiece>(path.front().get())) {
129           PathDiagnosticEventPiece *event =
130             cast<PathDiagnosticEventPiece>(piece);
131           // Check to see if we should keep one of the two pieces.  If we
132           // come up with a preference, record which piece to keep, and consume
133           // another piece from the path.
134           if (PathDiagnosticEventPiece *pieceToKeep =
135               eventsDescribeSameCondition(event, nextEvent)) {
136             piece = pieceToKeep;
137             path.pop_front();
138             ++i;
139           }
140         }
141         break;
142       }
143     }
144     path.push_back(piece);
145   }
146 }
147 
148 /// A map from PathDiagnosticPiece to the LocationContext of the inlined
149 /// function call it represents.
150 typedef llvm::DenseMap<const PathPieces *, const LocationContext *>
151         LocationContextMap;
152 
153 /// Recursively scan through a path and prune out calls and macros pieces
154 /// that aren't needed.  Return true if afterwards the path contains
155 /// "interesting stuff" which means it shouldn't be pruned from the parent path.
removeUnneededCalls(PathPieces & pieces,BugReport * R,LocationContextMap & LCM)156 static bool removeUnneededCalls(PathPieces &pieces, BugReport *R,
157                                 LocationContextMap &LCM) {
158   bool containsSomethingInteresting = false;
159   const unsigned N = pieces.size();
160 
161   for (unsigned i = 0 ; i < N ; ++i) {
162     // Remove the front piece from the path.  If it is still something we
163     // want to keep once we are done, we will push it back on the end.
164     IntrusiveRefCntPtr<PathDiagnosticPiece> piece(pieces.front());
165     pieces.pop_front();
166 
167     switch (piece->getKind()) {
168       case PathDiagnosticPiece::Call: {
169         PathDiagnosticCallPiece *call = cast<PathDiagnosticCallPiece>(piece);
170         // Check if the location context is interesting.
171         assert(LCM.count(&call->path));
172         if (R->isInteresting(LCM[&call->path])) {
173           containsSomethingInteresting = true;
174           break;
175         }
176 
177         if (!removeUnneededCalls(call->path, R, LCM))
178           continue;
179 
180         containsSomethingInteresting = true;
181         break;
182       }
183       case PathDiagnosticPiece::Macro: {
184         PathDiagnosticMacroPiece *macro = cast<PathDiagnosticMacroPiece>(piece);
185         if (!removeUnneededCalls(macro->subPieces, R, LCM))
186           continue;
187         containsSomethingInteresting = true;
188         break;
189       }
190       case PathDiagnosticPiece::Event: {
191         PathDiagnosticEventPiece *event = cast<PathDiagnosticEventPiece>(piece);
192 
193         // We never throw away an event, but we do throw it away wholesale
194         // as part of a path if we throw the entire path away.
195         containsSomethingInteresting |= !event->isPrunable();
196         break;
197       }
198       case PathDiagnosticPiece::ControlFlow:
199         break;
200     }
201 
202     pieces.push_back(piece);
203   }
204 
205   return containsSomethingInteresting;
206 }
207 
208 /// Returns true if the given decl has been implicitly given a body, either by
209 /// the analyzer or by the compiler proper.
hasImplicitBody(const Decl * D)210 static bool hasImplicitBody(const Decl *D) {
211   assert(D);
212   return D->isImplicit() || !D->hasBody();
213 }
214 
215 /// Recursively scan through a path and make sure that all call pieces have
216 /// valid locations.
217 static void
adjustCallLocations(PathPieces & Pieces,PathDiagnosticLocation * LastCallLocation=nullptr)218 adjustCallLocations(PathPieces &Pieces,
219                     PathDiagnosticLocation *LastCallLocation = nullptr) {
220   for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E; ++I) {
221     PathDiagnosticCallPiece *Call = dyn_cast<PathDiagnosticCallPiece>(*I);
222 
223     if (!Call) {
224       assert((*I)->getLocation().asLocation().isValid());
225       continue;
226     }
227 
228     if (LastCallLocation) {
229       bool CallerIsImplicit = hasImplicitBody(Call->getCaller());
230       if (CallerIsImplicit || !Call->callEnter.asLocation().isValid())
231         Call->callEnter = *LastCallLocation;
232       if (CallerIsImplicit || !Call->callReturn.asLocation().isValid())
233         Call->callReturn = *LastCallLocation;
234     }
235 
236     // Recursively clean out the subclass.  Keep this call around if
237     // it contains any informative diagnostics.
238     PathDiagnosticLocation *ThisCallLocation;
239     if (Call->callEnterWithin.asLocation().isValid() &&
240         !hasImplicitBody(Call->getCallee()))
241       ThisCallLocation = &Call->callEnterWithin;
242     else
243       ThisCallLocation = &Call->callEnter;
244 
245     assert(ThisCallLocation && "Outermost call has an invalid location");
246     adjustCallLocations(Call->path, ThisCallLocation);
247   }
248 }
249 
250 /// Remove edges in and out of C++ default initializer expressions. These are
251 /// for fields that have in-class initializers, as opposed to being initialized
252 /// explicitly in a constructor or braced list.
removeEdgesToDefaultInitializers(PathPieces & Pieces)253 static void removeEdgesToDefaultInitializers(PathPieces &Pieces) {
254   for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) {
255     if (PathDiagnosticCallPiece *C = dyn_cast<PathDiagnosticCallPiece>(*I))
256       removeEdgesToDefaultInitializers(C->path);
257 
258     if (PathDiagnosticMacroPiece *M = dyn_cast<PathDiagnosticMacroPiece>(*I))
259       removeEdgesToDefaultInitializers(M->subPieces);
260 
261     if (PathDiagnosticControlFlowPiece *CF =
262           dyn_cast<PathDiagnosticControlFlowPiece>(*I)) {
263       const Stmt *Start = CF->getStartLocation().asStmt();
264       const Stmt *End = CF->getEndLocation().asStmt();
265       if (Start && isa<CXXDefaultInitExpr>(Start)) {
266         I = Pieces.erase(I);
267         continue;
268       } else if (End && isa<CXXDefaultInitExpr>(End)) {
269         PathPieces::iterator Next = std::next(I);
270         if (Next != E) {
271           if (PathDiagnosticControlFlowPiece *NextCF =
272                 dyn_cast<PathDiagnosticControlFlowPiece>(*Next)) {
273             NextCF->setStartLocation(CF->getStartLocation());
274           }
275         }
276         I = Pieces.erase(I);
277         continue;
278       }
279     }
280 
281     I++;
282   }
283 }
284 
285 /// Remove all pieces with invalid locations as these cannot be serialized.
286 /// We might have pieces with invalid locations as a result of inlining Body
287 /// Farm generated functions.
removePiecesWithInvalidLocations(PathPieces & Pieces)288 static void removePiecesWithInvalidLocations(PathPieces &Pieces) {
289   for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) {
290     if (PathDiagnosticCallPiece *C = dyn_cast<PathDiagnosticCallPiece>(*I))
291       removePiecesWithInvalidLocations(C->path);
292 
293     if (PathDiagnosticMacroPiece *M = dyn_cast<PathDiagnosticMacroPiece>(*I))
294       removePiecesWithInvalidLocations(M->subPieces);
295 
296     if (!(*I)->getLocation().isValid() ||
297         !(*I)->getLocation().asLocation().isValid()) {
298       I = Pieces.erase(I);
299       continue;
300     }
301     I++;
302   }
303 }
304 
305 //===----------------------------------------------------------------------===//
306 // PathDiagnosticBuilder and its associated routines and helper objects.
307 //===----------------------------------------------------------------------===//
308 
309 namespace {
310 class NodeMapClosure : public BugReport::NodeResolver {
311   InterExplodedGraphMap &M;
312 public:
NodeMapClosure(InterExplodedGraphMap & m)313   NodeMapClosure(InterExplodedGraphMap &m) : M(m) {}
314 
getOriginalNode(const ExplodedNode * N)315   const ExplodedNode *getOriginalNode(const ExplodedNode *N) override {
316     return M.lookup(N);
317   }
318 };
319 
320 class PathDiagnosticBuilder : public BugReporterContext {
321   BugReport *R;
322   PathDiagnosticConsumer *PDC;
323   NodeMapClosure NMC;
324 public:
325   const LocationContext *LC;
326 
PathDiagnosticBuilder(GRBugReporter & br,BugReport * r,InterExplodedGraphMap & Backmap,PathDiagnosticConsumer * pdc)327   PathDiagnosticBuilder(GRBugReporter &br,
328                         BugReport *r, InterExplodedGraphMap &Backmap,
329                         PathDiagnosticConsumer *pdc)
330     : BugReporterContext(br),
331       R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext())
332   {}
333 
334   PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N);
335 
336   PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os,
337                                             const ExplodedNode *N);
338 
getBugReport()339   BugReport *getBugReport() { return R; }
340 
getCodeDecl()341   Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); }
342 
getParentMap()343   ParentMap& getParentMap() { return LC->getParentMap(); }
344 
getParent(const Stmt * S)345   const Stmt *getParent(const Stmt *S) {
346     return getParentMap().getParent(S);
347   }
348 
getNodeResolver()349   NodeMapClosure& getNodeResolver() override { return NMC; }
350 
351   PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S);
352 
getGenerationScheme() const353   PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const {
354     return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive;
355   }
356 
supportsLogicalOpControlFlow() const357   bool supportsLogicalOpControlFlow() const {
358     return PDC ? PDC->supportsLogicalOpControlFlow() : true;
359   }
360 };
361 } // end anonymous namespace
362 
363 PathDiagnosticLocation
ExecutionContinues(const ExplodedNode * N)364 PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) {
365   if (const Stmt *S = PathDiagnosticLocation::getNextStmt(N))
366     return PathDiagnosticLocation(S, getSourceManager(), LC);
367 
368   return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(),
369                                                getSourceManager());
370 }
371 
372 PathDiagnosticLocation
ExecutionContinues(llvm::raw_string_ostream & os,const ExplodedNode * N)373 PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os,
374                                           const ExplodedNode *N) {
375 
376   // Slow, but probably doesn't matter.
377   if (os.str().empty())
378     os << ' ';
379 
380   const PathDiagnosticLocation &Loc = ExecutionContinues(N);
381 
382   if (Loc.asStmt())
383     os << "Execution continues on line "
384        << getSourceManager().getExpansionLineNumber(Loc.asLocation())
385        << '.';
386   else {
387     os << "Execution jumps to the end of the ";
388     const Decl *D = N->getLocationContext()->getDecl();
389     if (isa<ObjCMethodDecl>(D))
390       os << "method";
391     else if (isa<FunctionDecl>(D))
392       os << "function";
393     else {
394       assert(isa<BlockDecl>(D));
395       os << "anonymous block";
396     }
397     os << '.';
398   }
399 
400   return Loc;
401 }
402 
getEnclosingParent(const Stmt * S,const ParentMap & PM)403 static const Stmt *getEnclosingParent(const Stmt *S, const ParentMap &PM) {
404   if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S)))
405     return PM.getParentIgnoreParens(S);
406 
407   const Stmt *Parent = PM.getParentIgnoreParens(S);
408   if (!Parent)
409     return nullptr;
410 
411   switch (Parent->getStmtClass()) {
412   case Stmt::ForStmtClass:
413   case Stmt::DoStmtClass:
414   case Stmt::WhileStmtClass:
415   case Stmt::ObjCForCollectionStmtClass:
416   case Stmt::CXXForRangeStmtClass:
417     return Parent;
418   default:
419     break;
420   }
421 
422   return nullptr;
423 }
424 
425 static PathDiagnosticLocation
getEnclosingStmtLocation(const Stmt * S,SourceManager & SMgr,const ParentMap & P,const LocationContext * LC,bool allowNestedContexts)426 getEnclosingStmtLocation(const Stmt *S, SourceManager &SMgr, const ParentMap &P,
427                          const LocationContext *LC, bool allowNestedContexts) {
428   if (!S)
429     return PathDiagnosticLocation();
430 
431   while (const Stmt *Parent = getEnclosingParent(S, P)) {
432     switch (Parent->getStmtClass()) {
433       case Stmt::BinaryOperatorClass: {
434         const BinaryOperator *B = cast<BinaryOperator>(Parent);
435         if (B->isLogicalOp())
436           return PathDiagnosticLocation(allowNestedContexts ? B : S, SMgr, LC);
437         break;
438       }
439       case Stmt::CompoundStmtClass:
440       case Stmt::StmtExprClass:
441         return PathDiagnosticLocation(S, SMgr, LC);
442       case Stmt::ChooseExprClass:
443         // Similar to '?' if we are referring to condition, just have the edge
444         // point to the entire choose expression.
445         if (allowNestedContexts || cast<ChooseExpr>(Parent)->getCond() == S)
446           return PathDiagnosticLocation(Parent, SMgr, LC);
447         else
448           return PathDiagnosticLocation(S, SMgr, LC);
449       case Stmt::BinaryConditionalOperatorClass:
450       case Stmt::ConditionalOperatorClass:
451         // For '?', if we are referring to condition, just have the edge point
452         // to the entire '?' expression.
453         if (allowNestedContexts ||
454             cast<AbstractConditionalOperator>(Parent)->getCond() == S)
455           return PathDiagnosticLocation(Parent, SMgr, LC);
456         else
457           return PathDiagnosticLocation(S, SMgr, LC);
458       case Stmt::CXXForRangeStmtClass:
459         if (cast<CXXForRangeStmt>(Parent)->getBody() == S)
460           return PathDiagnosticLocation(S, SMgr, LC);
461         break;
462       case Stmt::DoStmtClass:
463           return PathDiagnosticLocation(S, SMgr, LC);
464       case Stmt::ForStmtClass:
465         if (cast<ForStmt>(Parent)->getBody() == S)
466           return PathDiagnosticLocation(S, SMgr, LC);
467         break;
468       case Stmt::IfStmtClass:
469         if (cast<IfStmt>(Parent)->getCond() != S)
470           return PathDiagnosticLocation(S, SMgr, LC);
471         break;
472       case Stmt::ObjCForCollectionStmtClass:
473         if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S)
474           return PathDiagnosticLocation(S, SMgr, LC);
475         break;
476       case Stmt::WhileStmtClass:
477         if (cast<WhileStmt>(Parent)->getCond() != S)
478           return PathDiagnosticLocation(S, SMgr, LC);
479         break;
480       default:
481         break;
482     }
483 
484     S = Parent;
485   }
486 
487   assert(S && "Cannot have null Stmt for PathDiagnosticLocation");
488 
489   return PathDiagnosticLocation(S, SMgr, LC);
490 }
491 
492 PathDiagnosticLocation
getEnclosingStmtLocation(const Stmt * S)493 PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) {
494   assert(S && "Null Stmt passed to getEnclosingStmtLocation");
495   return ::getEnclosingStmtLocation(S, getSourceManager(), getParentMap(), LC,
496                                     /*allowNestedContexts=*/false);
497 }
498 
499 //===----------------------------------------------------------------------===//
500 // "Visitors only" path diagnostic generation algorithm.
501 //===----------------------------------------------------------------------===//
GenerateVisitorsOnlyPathDiagnostic(PathDiagnostic & PD,PathDiagnosticBuilder & PDB,const ExplodedNode * N,ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors)502 static bool GenerateVisitorsOnlyPathDiagnostic(
503     PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
504     ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
505   // All path generation skips the very first node (the error node).
506   // This is because there is special handling for the end-of-path note.
507   N = N->getFirstPred();
508   if (!N)
509     return true;
510 
511   BugReport *R = PDB.getBugReport();
512   while (const ExplodedNode *Pred = N->getFirstPred()) {
513     for (auto &V : visitors) {
514       // Visit all the node pairs, but throw the path pieces away.
515       PathDiagnosticPiece *Piece = V->VisitNode(N, Pred, PDB, *R);
516       delete Piece;
517     }
518 
519     N = Pred;
520   }
521 
522   return R->isValid();
523 }
524 
525 //===----------------------------------------------------------------------===//
526 // "Minimal" path diagnostic generation algorithm.
527 //===----------------------------------------------------------------------===//
528 typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair;
529 typedef SmallVector<StackDiagPair, 6> StackDiagVector;
530 
updateStackPiecesWithMessage(PathDiagnosticPiece * P,StackDiagVector & CallStack)531 static void updateStackPiecesWithMessage(PathDiagnosticPiece *P,
532                                          StackDiagVector &CallStack) {
533   // If the piece contains a special message, add it to all the call
534   // pieces on the active stack.
535   if (PathDiagnosticEventPiece *ep =
536         dyn_cast<PathDiagnosticEventPiece>(P)) {
537 
538     if (ep->hasCallStackHint())
539       for (StackDiagVector::iterator I = CallStack.begin(),
540                                      E = CallStack.end(); I != E; ++I) {
541         PathDiagnosticCallPiece *CP = I->first;
542         const ExplodedNode *N = I->second;
543         std::string stackMsg = ep->getCallStackMessage(N);
544 
545         // The last message on the path to final bug is the most important
546         // one. Since we traverse the path backwards, do not add the message
547         // if one has been previously added.
548         if  (!CP->hasCallStackMessage())
549           CP->setCallStackMessage(stackMsg);
550       }
551   }
552 }
553 
554 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM);
555 
GenerateMinimalPathDiagnostic(PathDiagnostic & PD,PathDiagnosticBuilder & PDB,const ExplodedNode * N,LocationContextMap & LCM,ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors)556 static bool GenerateMinimalPathDiagnostic(
557     PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
558     LocationContextMap &LCM,
559     ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
560 
561   SourceManager& SMgr = PDB.getSourceManager();
562   const LocationContext *LC = PDB.LC;
563   const ExplodedNode *NextNode = N->pred_empty()
564                                         ? nullptr : *(N->pred_begin());
565 
566   StackDiagVector CallStack;
567 
568   while (NextNode) {
569     N = NextNode;
570     PDB.LC = N->getLocationContext();
571     NextNode = N->getFirstPred();
572 
573     ProgramPoint P = N->getLocation();
574 
575     do {
576       if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
577         PathDiagnosticCallPiece *C =
578             PathDiagnosticCallPiece::construct(N, *CE, SMgr);
579         // Record the mapping from call piece to LocationContext.
580         LCM[&C->path] = CE->getCalleeContext();
581         PD.getActivePath().push_front(C);
582         PD.pushActivePath(&C->path);
583         CallStack.push_back(StackDiagPair(C, N));
584         break;
585       }
586 
587       if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
588         // Flush all locations, and pop the active path.
589         bool VisitedEntireCall = PD.isWithinCall();
590         PD.popActivePath();
591 
592         // Either we just added a bunch of stuff to the top-level path, or
593         // we have a previous CallExitEnd.  If the former, it means that the
594         // path terminated within a function call.  We must then take the
595         // current contents of the active path and place it within
596         // a new PathDiagnosticCallPiece.
597         PathDiagnosticCallPiece *C;
598         if (VisitedEntireCall) {
599           C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
600         } else {
601           const Decl *Caller = CE->getLocationContext()->getDecl();
602           C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
603           // Record the mapping from call piece to LocationContext.
604           LCM[&C->path] = CE->getCalleeContext();
605         }
606 
607         C->setCallee(*CE, SMgr);
608         if (!CallStack.empty()) {
609           assert(CallStack.back().first == C);
610           CallStack.pop_back();
611         }
612         break;
613       }
614 
615       if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
616         const CFGBlock *Src = BE->getSrc();
617         const CFGBlock *Dst = BE->getDst();
618         const Stmt *T = Src->getTerminator();
619 
620         if (!T)
621           break;
622 
623         PathDiagnosticLocation Start =
624             PathDiagnosticLocation::createBegin(T, SMgr,
625                 N->getLocationContext());
626 
627         switch (T->getStmtClass()) {
628         default:
629           break;
630 
631         case Stmt::GotoStmtClass:
632         case Stmt::IndirectGotoStmtClass: {
633           const Stmt *S = PathDiagnosticLocation::getNextStmt(N);
634 
635           if (!S)
636             break;
637 
638           std::string sbuf;
639           llvm::raw_string_ostream os(sbuf);
640           const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S);
641 
642           os << "Control jumps to line "
643               << End.asLocation().getExpansionLineNumber();
644           PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
645               Start, End, os.str()));
646           break;
647         }
648 
649         case Stmt::SwitchStmtClass: {
650           // Figure out what case arm we took.
651           std::string sbuf;
652           llvm::raw_string_ostream os(sbuf);
653 
654           if (const Stmt *S = Dst->getLabel()) {
655             PathDiagnosticLocation End(S, SMgr, LC);
656 
657             switch (S->getStmtClass()) {
658             default:
659               os << "No cases match in the switch statement. "
660               "Control jumps to line "
661               << End.asLocation().getExpansionLineNumber();
662               break;
663             case Stmt::DefaultStmtClass:
664               os << "Control jumps to the 'default' case at line "
665               << End.asLocation().getExpansionLineNumber();
666               break;
667 
668             case Stmt::CaseStmtClass: {
669               os << "Control jumps to 'case ";
670               const CaseStmt *Case = cast<CaseStmt>(S);
671               const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
672 
673               // Determine if it is an enum.
674               bool GetRawInt = true;
675 
676               if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) {
677                 // FIXME: Maybe this should be an assertion.  Are there cases
678                 // were it is not an EnumConstantDecl?
679                 const EnumConstantDecl *D =
680                     dyn_cast<EnumConstantDecl>(DR->getDecl());
681 
682                 if (D) {
683                   GetRawInt = false;
684                   os << *D;
685                 }
686               }
687 
688               if (GetRawInt)
689                 os << LHS->EvaluateKnownConstInt(PDB.getASTContext());
690 
691               os << ":'  at line "
692                   << End.asLocation().getExpansionLineNumber();
693               break;
694             }
695             }
696             PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
697                 Start, End, os.str()));
698           }
699           else {
700             os << "'Default' branch taken. ";
701             const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N);
702             PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
703                 Start, End, os.str()));
704           }
705 
706           break;
707         }
708 
709         case Stmt::BreakStmtClass:
710         case Stmt::ContinueStmtClass: {
711           std::string sbuf;
712           llvm::raw_string_ostream os(sbuf);
713           PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
714           PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
715               Start, End, os.str()));
716           break;
717         }
718 
719         // Determine control-flow for ternary '?'.
720         case Stmt::BinaryConditionalOperatorClass:
721         case Stmt::ConditionalOperatorClass: {
722           std::string sbuf;
723           llvm::raw_string_ostream os(sbuf);
724           os << "'?' condition is ";
725 
726           if (*(Src->succ_begin()+1) == Dst)
727             os << "false";
728           else
729             os << "true";
730 
731           PathDiagnosticLocation End = PDB.ExecutionContinues(N);
732 
733           if (const Stmt *S = End.asStmt())
734             End = PDB.getEnclosingStmtLocation(S);
735 
736           PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
737               Start, End, os.str()));
738           break;
739         }
740 
741         // Determine control-flow for short-circuited '&&' and '||'.
742         case Stmt::BinaryOperatorClass: {
743           if (!PDB.supportsLogicalOpControlFlow())
744             break;
745 
746           const BinaryOperator *B = cast<BinaryOperator>(T);
747           std::string sbuf;
748           llvm::raw_string_ostream os(sbuf);
749           os << "Left side of '";
750 
751           if (B->getOpcode() == BO_LAnd) {
752             os << "&&" << "' is ";
753 
754             if (*(Src->succ_begin()+1) == Dst) {
755               os << "false";
756               PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
757               PathDiagnosticLocation Start =
758                   PathDiagnosticLocation::createOperatorLoc(B, SMgr);
759               PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
760                   Start, End, os.str()));
761             }
762             else {
763               os << "true";
764               PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
765               PathDiagnosticLocation End = PDB.ExecutionContinues(N);
766               PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
767                   Start, End, os.str()));
768             }
769           }
770           else {
771             assert(B->getOpcode() == BO_LOr);
772             os << "||" << "' is ";
773 
774             if (*(Src->succ_begin()+1) == Dst) {
775               os << "false";
776               PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
777               PathDiagnosticLocation End = PDB.ExecutionContinues(N);
778               PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
779                   Start, End, os.str()));
780             }
781             else {
782               os << "true";
783               PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
784               PathDiagnosticLocation Start =
785                   PathDiagnosticLocation::createOperatorLoc(B, SMgr);
786               PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
787                   Start, End, os.str()));
788             }
789           }
790 
791           break;
792         }
793 
794         case Stmt::DoStmtClass:  {
795           if (*(Src->succ_begin()) == Dst) {
796             std::string sbuf;
797             llvm::raw_string_ostream os(sbuf);
798 
799             os << "Loop condition is true. ";
800             PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
801 
802             if (const Stmt *S = End.asStmt())
803               End = PDB.getEnclosingStmtLocation(S);
804 
805             PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
806                 Start, End, os.str()));
807           }
808           else {
809             PathDiagnosticLocation End = PDB.ExecutionContinues(N);
810 
811             if (const Stmt *S = End.asStmt())
812               End = PDB.getEnclosingStmtLocation(S);
813 
814             PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
815                 Start, End, "Loop condition is false.  Exiting loop"));
816           }
817 
818           break;
819         }
820 
821         case Stmt::WhileStmtClass:
822         case Stmt::ForStmtClass: {
823           if (*(Src->succ_begin()+1) == Dst) {
824             std::string sbuf;
825             llvm::raw_string_ostream os(sbuf);
826 
827             os << "Loop condition is false. ";
828             PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
829             if (const Stmt *S = End.asStmt())
830               End = PDB.getEnclosingStmtLocation(S);
831 
832             PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
833                 Start, End, os.str()));
834           }
835           else {
836             PathDiagnosticLocation End = PDB.ExecutionContinues(N);
837             if (const Stmt *S = End.asStmt())
838               End = PDB.getEnclosingStmtLocation(S);
839 
840             PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
841                 Start, End, "Loop condition is true.  Entering loop body"));
842           }
843 
844           break;
845         }
846 
847         case Stmt::IfStmtClass: {
848           PathDiagnosticLocation End = PDB.ExecutionContinues(N);
849 
850           if (const Stmt *S = End.asStmt())
851             End = PDB.getEnclosingStmtLocation(S);
852 
853           if (*(Src->succ_begin()+1) == Dst)
854             PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
855                 Start, End, "Taking false branch"));
856           else
857             PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(
858                 Start, End, "Taking true branch"));
859 
860           break;
861         }
862         }
863       }
864     } while(0);
865 
866     if (NextNode) {
867       // Add diagnostic pieces from custom visitors.
868       BugReport *R = PDB.getBugReport();
869       for (auto &V : visitors) {
870         if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *R)) {
871           PD.getActivePath().push_front(p);
872           updateStackPiecesWithMessage(p, CallStack);
873         }
874       }
875     }
876   }
877 
878   if (!PDB.getBugReport()->isValid())
879     return false;
880 
881   // After constructing the full PathDiagnostic, do a pass over it to compact
882   // PathDiagnosticPieces that occur within a macro.
883   CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager());
884   return true;
885 }
886 
887 //===----------------------------------------------------------------------===//
888 // "Extensive" PathDiagnostic generation.
889 //===----------------------------------------------------------------------===//
890 
IsControlFlowExpr(const Stmt * S)891 static bool IsControlFlowExpr(const Stmt *S) {
892   const Expr *E = dyn_cast<Expr>(S);
893 
894   if (!E)
895     return false;
896 
897   E = E->IgnoreParenCasts();
898 
899   if (isa<AbstractConditionalOperator>(E))
900     return true;
901 
902   if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E))
903     if (B->isLogicalOp())
904       return true;
905 
906   return false;
907 }
908 
909 namespace {
910 class ContextLocation : public PathDiagnosticLocation {
911   bool IsDead;
912 public:
ContextLocation(const PathDiagnosticLocation & L,bool isdead=false)913   ContextLocation(const PathDiagnosticLocation &L, bool isdead = false)
914     : PathDiagnosticLocation(L), IsDead(isdead) {}
915 
markDead()916   void markDead() { IsDead = true; }
isDead() const917   bool isDead() const { return IsDead; }
918 };
919 
cleanUpLocation(PathDiagnosticLocation L,const LocationContext * LC,bool firstCharOnly=false)920 static PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L,
921                                               const LocationContext *LC,
922                                               bool firstCharOnly = false) {
923   if (const Stmt *S = L.asStmt()) {
924     const Stmt *Original = S;
925     while (1) {
926       // Adjust the location for some expressions that are best referenced
927       // by one of their subexpressions.
928       switch (S->getStmtClass()) {
929         default:
930           break;
931         case Stmt::ParenExprClass:
932         case Stmt::GenericSelectionExprClass:
933           S = cast<Expr>(S)->IgnoreParens();
934           firstCharOnly = true;
935           continue;
936         case Stmt::BinaryConditionalOperatorClass:
937         case Stmt::ConditionalOperatorClass:
938           S = cast<AbstractConditionalOperator>(S)->getCond();
939           firstCharOnly = true;
940           continue;
941         case Stmt::ChooseExprClass:
942           S = cast<ChooseExpr>(S)->getCond();
943           firstCharOnly = true;
944           continue;
945         case Stmt::BinaryOperatorClass:
946           S = cast<BinaryOperator>(S)->getLHS();
947           firstCharOnly = true;
948           continue;
949       }
950 
951       break;
952     }
953 
954     if (S != Original)
955       L = PathDiagnosticLocation(S, L.getManager(), LC);
956   }
957 
958   if (firstCharOnly)
959     L  = PathDiagnosticLocation::createSingleLocation(L);
960 
961   return L;
962 }
963 
964 class EdgeBuilder {
965   std::vector<ContextLocation> CLocs;
966   typedef std::vector<ContextLocation>::iterator iterator;
967   PathDiagnostic &PD;
968   PathDiagnosticBuilder &PDB;
969   PathDiagnosticLocation PrevLoc;
970 
971   bool IsConsumedExpr(const PathDiagnosticLocation &L);
972 
973   bool containsLocation(const PathDiagnosticLocation &Container,
974                         const PathDiagnosticLocation &Containee);
975 
976   PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L);
977 
978 
979 
popLocation()980   void popLocation() {
981     if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) {
982       // For contexts, we only one the first character as the range.
983       rawAddEdge(cleanUpLocation(CLocs.back(), PDB.LC, true));
984     }
985     CLocs.pop_back();
986   }
987 
988 public:
EdgeBuilder(PathDiagnostic & pd,PathDiagnosticBuilder & pdb)989   EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb)
990     : PD(pd), PDB(pdb) {
991 
992       // If the PathDiagnostic already has pieces, add the enclosing statement
993       // of the first piece as a context as well.
994       if (!PD.path.empty()) {
995         PrevLoc = (*PD.path.begin())->getLocation();
996 
997         if (const Stmt *S = PrevLoc.asStmt())
998           addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
999       }
1000   }
1001 
~EdgeBuilder()1002   ~EdgeBuilder() {
1003     while (!CLocs.empty()) popLocation();
1004 
1005     // Finally, add an initial edge from the start location of the first
1006     // statement (if it doesn't already exist).
1007     PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin(
1008                                                        PDB.LC,
1009                                                        PDB.getSourceManager());
1010     if (L.isValid())
1011       rawAddEdge(L);
1012   }
1013 
flushLocations()1014   void flushLocations() {
1015     while (!CLocs.empty())
1016       popLocation();
1017     PrevLoc = PathDiagnosticLocation();
1018   }
1019 
1020   void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false,
1021                bool IsPostJump = false);
1022 
1023   void rawAddEdge(PathDiagnosticLocation NewLoc);
1024 
1025   void addContext(const Stmt *S);
1026   void addContext(const PathDiagnosticLocation &L);
1027   void addExtendedContext(const Stmt *S);
1028 };
1029 } // end anonymous namespace
1030 
1031 
1032 PathDiagnosticLocation
getContextLocation(const PathDiagnosticLocation & L)1033 EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) {
1034   if (const Stmt *S = L.asStmt()) {
1035     if (IsControlFlowExpr(S))
1036       return L;
1037 
1038     return PDB.getEnclosingStmtLocation(S);
1039   }
1040 
1041   return L;
1042 }
1043 
containsLocation(const PathDiagnosticLocation & Container,const PathDiagnosticLocation & Containee)1044 bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container,
1045                                    const PathDiagnosticLocation &Containee) {
1046 
1047   if (Container == Containee)
1048     return true;
1049 
1050   if (Container.asDecl())
1051     return true;
1052 
1053   if (const Stmt *S = Containee.asStmt())
1054     if (const Stmt *ContainerS = Container.asStmt()) {
1055       while (S) {
1056         if (S == ContainerS)
1057           return true;
1058         S = PDB.getParent(S);
1059       }
1060       return false;
1061     }
1062 
1063   // Less accurate: compare using source ranges.
1064   SourceRange ContainerR = Container.asRange();
1065   SourceRange ContaineeR = Containee.asRange();
1066 
1067   SourceManager &SM = PDB.getSourceManager();
1068   SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin());
1069   SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd());
1070   SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin());
1071   SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd());
1072 
1073   unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg);
1074   unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd);
1075   unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg);
1076   unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd);
1077 
1078   assert(ContainerBegLine <= ContainerEndLine);
1079   assert(ContaineeBegLine <= ContaineeEndLine);
1080 
1081   return (ContainerBegLine <= ContaineeBegLine &&
1082           ContainerEndLine >= ContaineeEndLine &&
1083           (ContainerBegLine != ContaineeBegLine ||
1084            SM.getExpansionColumnNumber(ContainerRBeg) <=
1085            SM.getExpansionColumnNumber(ContaineeRBeg)) &&
1086           (ContainerEndLine != ContaineeEndLine ||
1087            SM.getExpansionColumnNumber(ContainerREnd) >=
1088            SM.getExpansionColumnNumber(ContaineeREnd)));
1089 }
1090 
rawAddEdge(PathDiagnosticLocation NewLoc)1091 void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) {
1092   if (!PrevLoc.isValid()) {
1093     PrevLoc = NewLoc;
1094     return;
1095   }
1096 
1097   const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc, PDB.LC);
1098   const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc, PDB.LC);
1099 
1100   if (PrevLocClean.asLocation().isInvalid()) {
1101     PrevLoc = NewLoc;
1102     return;
1103   }
1104 
1105   if (NewLocClean.asLocation() == PrevLocClean.asLocation())
1106     return;
1107 
1108   // FIXME: Ignore intra-macro edges for now.
1109   if (NewLocClean.asLocation().getExpansionLoc() ==
1110       PrevLocClean.asLocation().getExpansionLoc())
1111     return;
1112 
1113   PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean));
1114   PrevLoc = NewLoc;
1115 }
1116 
addEdge(PathDiagnosticLocation NewLoc,bool alwaysAdd,bool IsPostJump)1117 void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd,
1118                           bool IsPostJump) {
1119 
1120   if (!alwaysAdd && NewLoc.asLocation().isMacroID())
1121     return;
1122 
1123   const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc);
1124 
1125   while (!CLocs.empty()) {
1126     ContextLocation &TopContextLoc = CLocs.back();
1127 
1128     // Is the top location context the same as the one for the new location?
1129     if (TopContextLoc == CLoc) {
1130       if (alwaysAdd) {
1131         if (IsConsumedExpr(TopContextLoc))
1132           TopContextLoc.markDead();
1133 
1134         rawAddEdge(NewLoc);
1135       }
1136 
1137       if (IsPostJump)
1138         TopContextLoc.markDead();
1139       return;
1140     }
1141 
1142     if (containsLocation(TopContextLoc, CLoc)) {
1143       if (alwaysAdd) {
1144         rawAddEdge(NewLoc);
1145 
1146         if (IsConsumedExpr(CLoc)) {
1147           CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/true));
1148           return;
1149         }
1150       }
1151 
1152       CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/IsPostJump));
1153       return;
1154     }
1155 
1156     // Context does not contain the location.  Flush it.
1157     popLocation();
1158   }
1159 
1160   // If we reach here, there is no enclosing context.  Just add the edge.
1161   rawAddEdge(NewLoc);
1162 }
1163 
IsConsumedExpr(const PathDiagnosticLocation & L)1164 bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) {
1165   if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt()))
1166     return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X);
1167 
1168   return false;
1169 }
1170 
addExtendedContext(const Stmt * S)1171 void EdgeBuilder::addExtendedContext(const Stmt *S) {
1172   if (!S)
1173     return;
1174 
1175   const Stmt *Parent = PDB.getParent(S);
1176   while (Parent) {
1177     if (isa<CompoundStmt>(Parent))
1178       Parent = PDB.getParent(Parent);
1179     else
1180       break;
1181   }
1182 
1183   if (Parent) {
1184     switch (Parent->getStmtClass()) {
1185       case Stmt::DoStmtClass:
1186       case Stmt::ObjCAtSynchronizedStmtClass:
1187         addContext(Parent);
1188       default:
1189         break;
1190     }
1191   }
1192 
1193   addContext(S);
1194 }
1195 
addContext(const Stmt * S)1196 void EdgeBuilder::addContext(const Stmt *S) {
1197   if (!S)
1198     return;
1199 
1200   PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC);
1201   addContext(L);
1202 }
1203 
addContext(const PathDiagnosticLocation & L)1204 void EdgeBuilder::addContext(const PathDiagnosticLocation &L) {
1205   while (!CLocs.empty()) {
1206     const PathDiagnosticLocation &TopContextLoc = CLocs.back();
1207 
1208     // Is the top location context the same as the one for the new location?
1209     if (TopContextLoc == L)
1210       return;
1211 
1212     if (containsLocation(TopContextLoc, L)) {
1213       CLocs.push_back(L);
1214       return;
1215     }
1216 
1217     // Context does not contain the location.  Flush it.
1218     popLocation();
1219   }
1220 
1221   CLocs.push_back(L);
1222 }
1223 
1224 // Cone-of-influence: support the reverse propagation of "interesting" symbols
1225 // and values by tracing interesting calculations backwards through evaluated
1226 // expressions along a path.  This is probably overly complicated, but the idea
1227 // is that if an expression computed an "interesting" value, the child
1228 // expressions are are also likely to be "interesting" as well (which then
1229 // propagates to the values they in turn compute).  This reverse propagation
1230 // is needed to track interesting correlations across function call boundaries,
1231 // where formal arguments bind to actual arguments, etc.  This is also needed
1232 // because the constraint solver sometimes simplifies certain symbolic values
1233 // into constants when appropriate, and this complicates reasoning about
1234 // interesting values.
1235 typedef llvm::DenseSet<const Expr *> InterestingExprs;
1236 
reversePropagateIntererstingSymbols(BugReport & R,InterestingExprs & IE,const ProgramState * State,const Expr * Ex,const LocationContext * LCtx)1237 static void reversePropagateIntererstingSymbols(BugReport &R,
1238                                                 InterestingExprs &IE,
1239                                                 const ProgramState *State,
1240                                                 const Expr *Ex,
1241                                                 const LocationContext *LCtx) {
1242   SVal V = State->getSVal(Ex, LCtx);
1243   if (!(R.isInteresting(V) || IE.count(Ex)))
1244     return;
1245 
1246   switch (Ex->getStmtClass()) {
1247     default:
1248       if (!isa<CastExpr>(Ex))
1249         break;
1250       // Fall through.
1251     case Stmt::BinaryOperatorClass:
1252     case Stmt::UnaryOperatorClass: {
1253       for (const Stmt *SubStmt : Ex->children()) {
1254         if (const Expr *child = dyn_cast_or_null<Expr>(SubStmt)) {
1255           IE.insert(child);
1256           SVal ChildV = State->getSVal(child, LCtx);
1257           R.markInteresting(ChildV);
1258         }
1259       }
1260       break;
1261     }
1262   }
1263 
1264   R.markInteresting(V);
1265 }
1266 
reversePropagateInterestingSymbols(BugReport & R,InterestingExprs & IE,const ProgramState * State,const LocationContext * CalleeCtx,const LocationContext * CallerCtx)1267 static void reversePropagateInterestingSymbols(BugReport &R,
1268                                                InterestingExprs &IE,
1269                                                const ProgramState *State,
1270                                                const LocationContext *CalleeCtx,
1271                                                const LocationContext *CallerCtx)
1272 {
1273   // FIXME: Handle non-CallExpr-based CallEvents.
1274   const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame();
1275   const Stmt *CallSite = Callee->getCallSite();
1276   if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) {
1277     if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) {
1278       FunctionDecl::param_const_iterator PI = FD->param_begin(),
1279                                          PE = FD->param_end();
1280       CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end();
1281       for (; AI != AE && PI != PE; ++AI, ++PI) {
1282         if (const Expr *ArgE = *AI) {
1283           if (const ParmVarDecl *PD = *PI) {
1284             Loc LV = State->getLValue(PD, CalleeCtx);
1285             if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV)))
1286               IE.insert(ArgE);
1287           }
1288         }
1289       }
1290     }
1291   }
1292 }
1293 
1294 //===----------------------------------------------------------------------===//
1295 // Functions for determining if a loop was executed 0 times.
1296 //===----------------------------------------------------------------------===//
1297 
isLoop(const Stmt * Term)1298 static bool isLoop(const Stmt *Term) {
1299   switch (Term->getStmtClass()) {
1300     case Stmt::ForStmtClass:
1301     case Stmt::WhileStmtClass:
1302     case Stmt::ObjCForCollectionStmtClass:
1303     case Stmt::CXXForRangeStmtClass:
1304       return true;
1305     default:
1306       // Note that we intentionally do not include do..while here.
1307       return false;
1308   }
1309 }
1310 
isJumpToFalseBranch(const BlockEdge * BE)1311 static bool isJumpToFalseBranch(const BlockEdge *BE) {
1312   const CFGBlock *Src = BE->getSrc();
1313   assert(Src->succ_size() == 2);
1314   return (*(Src->succ_begin()+1) == BE->getDst());
1315 }
1316 
1317 /// Return true if the terminator is a loop and the destination is the
1318 /// false branch.
isLoopJumpPastBody(const Stmt * Term,const BlockEdge * BE)1319 static bool isLoopJumpPastBody(const Stmt *Term, const BlockEdge *BE) {
1320   if (!isLoop(Term))
1321     return false;
1322 
1323   // Did we take the false branch?
1324   return isJumpToFalseBranch(BE);
1325 }
1326 
isContainedByStmt(ParentMap & PM,const Stmt * S,const Stmt * SubS)1327 static bool isContainedByStmt(ParentMap &PM, const Stmt *S, const Stmt *SubS) {
1328   while (SubS) {
1329     if (SubS == S)
1330       return true;
1331     SubS = PM.getParent(SubS);
1332   }
1333   return false;
1334 }
1335 
getStmtBeforeCond(ParentMap & PM,const Stmt * Term,const ExplodedNode * N)1336 static const Stmt *getStmtBeforeCond(ParentMap &PM, const Stmt *Term,
1337                                      const ExplodedNode *N) {
1338   while (N) {
1339     Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>();
1340     if (SP) {
1341       const Stmt *S = SP->getStmt();
1342       if (!isContainedByStmt(PM, Term, S))
1343         return S;
1344     }
1345     N = N->getFirstPred();
1346   }
1347   return nullptr;
1348 }
1349 
isInLoopBody(ParentMap & PM,const Stmt * S,const Stmt * Term)1350 static bool isInLoopBody(ParentMap &PM, const Stmt *S, const Stmt *Term) {
1351   const Stmt *LoopBody = nullptr;
1352   switch (Term->getStmtClass()) {
1353     case Stmt::CXXForRangeStmtClass: {
1354       const CXXForRangeStmt *FR = cast<CXXForRangeStmt>(Term);
1355       if (isContainedByStmt(PM, FR->getInc(), S))
1356         return true;
1357       if (isContainedByStmt(PM, FR->getLoopVarStmt(), S))
1358         return true;
1359       LoopBody = FR->getBody();
1360       break;
1361     }
1362     case Stmt::ForStmtClass: {
1363       const ForStmt *FS = cast<ForStmt>(Term);
1364       if (isContainedByStmt(PM, FS->getInc(), S))
1365         return true;
1366       LoopBody = FS->getBody();
1367       break;
1368     }
1369     case Stmt::ObjCForCollectionStmtClass: {
1370       const ObjCForCollectionStmt *FC = cast<ObjCForCollectionStmt>(Term);
1371       LoopBody = FC->getBody();
1372       break;
1373     }
1374     case Stmt::WhileStmtClass:
1375       LoopBody = cast<WhileStmt>(Term)->getBody();
1376       break;
1377     default:
1378       return false;
1379   }
1380   return isContainedByStmt(PM, LoopBody, S);
1381 }
1382 
1383 //===----------------------------------------------------------------------===//
1384 // Top-level logic for generating extensive path diagnostics.
1385 //===----------------------------------------------------------------------===//
1386 
GenerateExtensivePathDiagnostic(PathDiagnostic & PD,PathDiagnosticBuilder & PDB,const ExplodedNode * N,LocationContextMap & LCM,ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors)1387 static bool GenerateExtensivePathDiagnostic(
1388     PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
1389     LocationContextMap &LCM,
1390     ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
1391   EdgeBuilder EB(PD, PDB);
1392   const SourceManager& SM = PDB.getSourceManager();
1393   StackDiagVector CallStack;
1394   InterestingExprs IE;
1395 
1396   const ExplodedNode *NextNode = N->pred_empty() ? nullptr : *(N->pred_begin());
1397   while (NextNode) {
1398     N = NextNode;
1399     NextNode = N->getFirstPred();
1400     ProgramPoint P = N->getLocation();
1401 
1402     do {
1403       if (Optional<PostStmt> PS = P.getAs<PostStmt>()) {
1404         if (const Expr *Ex = PS->getStmtAs<Expr>())
1405           reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1406                                               N->getState().get(), Ex,
1407                                               N->getLocationContext());
1408       }
1409 
1410       if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
1411         const Stmt *S = CE->getCalleeContext()->getCallSite();
1412         if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) {
1413             reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1414                                                 N->getState().get(), Ex,
1415                                                 N->getLocationContext());
1416         }
1417 
1418         PathDiagnosticCallPiece *C =
1419           PathDiagnosticCallPiece::construct(N, *CE, SM);
1420         LCM[&C->path] = CE->getCalleeContext();
1421 
1422         EB.addEdge(C->callReturn, /*AlwaysAdd=*/true, /*IsPostJump=*/true);
1423         EB.flushLocations();
1424 
1425         PD.getActivePath().push_front(C);
1426         PD.pushActivePath(&C->path);
1427         CallStack.push_back(StackDiagPair(C, N));
1428         break;
1429       }
1430 
1431       // Pop the call hierarchy if we are done walking the contents
1432       // of a function call.
1433       if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
1434         // Add an edge to the start of the function.
1435         const Decl *D = CE->getCalleeContext()->getDecl();
1436         PathDiagnosticLocation pos =
1437           PathDiagnosticLocation::createBegin(D, SM);
1438         EB.addEdge(pos);
1439 
1440         // Flush all locations, and pop the active path.
1441         bool VisitedEntireCall = PD.isWithinCall();
1442         EB.flushLocations();
1443         PD.popActivePath();
1444         PDB.LC = N->getLocationContext();
1445 
1446         // Either we just added a bunch of stuff to the top-level path, or
1447         // we have a previous CallExitEnd.  If the former, it means that the
1448         // path terminated within a function call.  We must then take the
1449         // current contents of the active path and place it within
1450         // a new PathDiagnosticCallPiece.
1451         PathDiagnosticCallPiece *C;
1452         if (VisitedEntireCall) {
1453           C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front());
1454         } else {
1455           const Decl *Caller = CE->getLocationContext()->getDecl();
1456           C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
1457           LCM[&C->path] = CE->getCalleeContext();
1458         }
1459 
1460         C->setCallee(*CE, SM);
1461         EB.addContext(C->getLocation());
1462 
1463         if (!CallStack.empty()) {
1464           assert(CallStack.back().first == C);
1465           CallStack.pop_back();
1466         }
1467         break;
1468       }
1469 
1470       // Note that is important that we update the LocationContext
1471       // after looking at CallExits.  CallExit basically adds an
1472       // edge in the *caller*, so we don't want to update the LocationContext
1473       // too soon.
1474       PDB.LC = N->getLocationContext();
1475 
1476       // Block edges.
1477       if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
1478         // Does this represent entering a call?  If so, look at propagating
1479         // interesting symbols across call boundaries.
1480         if (NextNode) {
1481           const LocationContext *CallerCtx = NextNode->getLocationContext();
1482           const LocationContext *CalleeCtx = PDB.LC;
1483           if (CallerCtx != CalleeCtx) {
1484             reversePropagateInterestingSymbols(*PDB.getBugReport(), IE,
1485                                                N->getState().get(),
1486                                                CalleeCtx, CallerCtx);
1487           }
1488         }
1489 
1490         // Are we jumping to the head of a loop?  Add a special diagnostic.
1491         if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) {
1492           PathDiagnosticLocation L(Loop, SM, PDB.LC);
1493           const CompoundStmt *CS = nullptr;
1494 
1495           if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
1496             CS = dyn_cast<CompoundStmt>(FS->getBody());
1497           else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
1498             CS = dyn_cast<CompoundStmt>(WS->getBody());
1499 
1500           PathDiagnosticEventPiece *p =
1501             new PathDiagnosticEventPiece(L,
1502                                         "Looping back to the head of the loop");
1503           p->setPrunable(true);
1504 
1505           EB.addEdge(p->getLocation(), true);
1506           PD.getActivePath().push_front(p);
1507 
1508           if (CS) {
1509             PathDiagnosticLocation BL =
1510               PathDiagnosticLocation::createEndBrace(CS, SM);
1511             EB.addEdge(BL);
1512           }
1513         }
1514 
1515         const CFGBlock *BSrc = BE->getSrc();
1516         ParentMap &PM = PDB.getParentMap();
1517 
1518         if (const Stmt *Term = BSrc->getTerminator()) {
1519           // Are we jumping past the loop body without ever executing the
1520           // loop (because the condition was false)?
1521           if (isLoopJumpPastBody(Term, &*BE) &&
1522               !isInLoopBody(PM,
1523                             getStmtBeforeCond(PM,
1524                                               BSrc->getTerminatorCondition(),
1525                                               N),
1526                             Term)) {
1527             PathDiagnosticLocation L(Term, SM, PDB.LC);
1528             PathDiagnosticEventPiece *PE =
1529                 new PathDiagnosticEventPiece(L, "Loop body executed 0 times");
1530             PE->setPrunable(true);
1531 
1532             EB.addEdge(PE->getLocation(), true);
1533             PD.getActivePath().push_front(PE);
1534           }
1535 
1536           // In any case, add the terminator as the current statement
1537           // context for control edges.
1538           EB.addContext(Term);
1539         }
1540 
1541         break;
1542       }
1543 
1544       if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) {
1545         Optional<CFGElement> First = BE->getFirstElement();
1546         if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) {
1547           const Stmt *stmt = S->getStmt();
1548           if (IsControlFlowExpr(stmt)) {
1549             // Add the proper context for '&&', '||', and '?'.
1550             EB.addContext(stmt);
1551           }
1552           else
1553             EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt());
1554         }
1555 
1556         break;
1557       }
1558 
1559 
1560     } while (0);
1561 
1562     if (!NextNode)
1563       continue;
1564 
1565     // Add pieces from custom visitors.
1566     BugReport *R = PDB.getBugReport();
1567     for (auto &V : visitors) {
1568       if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *R)) {
1569         const PathDiagnosticLocation &Loc = p->getLocation();
1570         EB.addEdge(Loc, true);
1571         PD.getActivePath().push_front(p);
1572         updateStackPiecesWithMessage(p, CallStack);
1573 
1574         if (const Stmt *S = Loc.asStmt())
1575           EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
1576       }
1577     }
1578   }
1579 
1580   return PDB.getBugReport()->isValid();
1581 }
1582 
1583 /// \brief Adds a sanitized control-flow diagnostic edge to a path.
addEdgeToPath(PathPieces & path,PathDiagnosticLocation & PrevLoc,PathDiagnosticLocation NewLoc,const LocationContext * LC)1584 static void addEdgeToPath(PathPieces &path,
1585                           PathDiagnosticLocation &PrevLoc,
1586                           PathDiagnosticLocation NewLoc,
1587                           const LocationContext *LC) {
1588   if (!NewLoc.isValid())
1589     return;
1590 
1591   SourceLocation NewLocL = NewLoc.asLocation();
1592   if (NewLocL.isInvalid())
1593     return;
1594 
1595   if (!PrevLoc.isValid() || !PrevLoc.asLocation().isValid()) {
1596     PrevLoc = NewLoc;
1597     return;
1598   }
1599 
1600   // Ignore self-edges, which occur when there are multiple nodes at the same
1601   // statement.
1602   if (NewLoc.asStmt() && NewLoc.asStmt() == PrevLoc.asStmt())
1603     return;
1604 
1605   path.push_front(new PathDiagnosticControlFlowPiece(NewLoc,
1606                                                      PrevLoc));
1607   PrevLoc = NewLoc;
1608 }
1609 
1610 /// A customized wrapper for CFGBlock::getTerminatorCondition()
1611 /// which returns the element for ObjCForCollectionStmts.
getTerminatorCondition(const CFGBlock * B)1612 static const Stmt *getTerminatorCondition(const CFGBlock *B) {
1613   const Stmt *S = B->getTerminatorCondition();
1614   if (const ObjCForCollectionStmt *FS =
1615       dyn_cast_or_null<ObjCForCollectionStmt>(S))
1616     return FS->getElement();
1617   return S;
1618 }
1619 
1620 static const char StrEnteringLoop[] = "Entering loop body";
1621 static const char StrLoopBodyZero[] = "Loop body executed 0 times";
1622 static const char StrLoopRangeEmpty[] =
1623   "Loop body skipped when range is empty";
1624 static const char StrLoopCollectionEmpty[] =
1625   "Loop body skipped when collection is empty";
1626 
GenerateAlternateExtensivePathDiagnostic(PathDiagnostic & PD,PathDiagnosticBuilder & PDB,const ExplodedNode * N,LocationContextMap & LCM,ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors)1627 static bool GenerateAlternateExtensivePathDiagnostic(
1628     PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
1629     LocationContextMap &LCM,
1630     ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
1631 
1632   BugReport *report = PDB.getBugReport();
1633   const SourceManager& SM = PDB.getSourceManager();
1634   StackDiagVector CallStack;
1635   InterestingExprs IE;
1636 
1637   PathDiagnosticLocation PrevLoc = PD.getLocation();
1638 
1639   const ExplodedNode *NextNode = N->getFirstPred();
1640   while (NextNode) {
1641     N = NextNode;
1642     NextNode = N->getFirstPred();
1643     ProgramPoint P = N->getLocation();
1644 
1645     do {
1646       // Have we encountered an entrance to a call?  It may be
1647       // the case that we have not encountered a matching
1648       // call exit before this point.  This means that the path
1649       // terminated within the call itself.
1650       if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
1651         // Add an edge to the start of the function.
1652         const StackFrameContext *CalleeLC = CE->getCalleeContext();
1653         const Decl *D = CalleeLC->getDecl();
1654         addEdgeToPath(PD.getActivePath(), PrevLoc,
1655                       PathDiagnosticLocation::createBegin(D, SM),
1656                       CalleeLC);
1657 
1658         // Did we visit an entire call?
1659         bool VisitedEntireCall = PD.isWithinCall();
1660         PD.popActivePath();
1661 
1662         PathDiagnosticCallPiece *C;
1663         if (VisitedEntireCall) {
1664           PathDiagnosticPiece *P = PD.getActivePath().front().get();
1665           C = cast<PathDiagnosticCallPiece>(P);
1666         } else {
1667           const Decl *Caller = CE->getLocationContext()->getDecl();
1668           C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
1669 
1670           // Since we just transferred the path over to the call piece,
1671           // reset the mapping from active to location context.
1672           assert(PD.getActivePath().size() == 1 &&
1673                  PD.getActivePath().front() == C);
1674           LCM[&PD.getActivePath()] = nullptr;
1675 
1676           // Record the location context mapping for the path within
1677           // the call.
1678           assert(LCM[&C->path] == nullptr ||
1679                  LCM[&C->path] == CE->getCalleeContext());
1680           LCM[&C->path] = CE->getCalleeContext();
1681 
1682           // If this is the first item in the active path, record
1683           // the new mapping from active path to location context.
1684           const LocationContext *&NewLC = LCM[&PD.getActivePath()];
1685           if (!NewLC)
1686             NewLC = N->getLocationContext();
1687 
1688           PDB.LC = NewLC;
1689         }
1690         C->setCallee(*CE, SM);
1691 
1692         // Update the previous location in the active path.
1693         PrevLoc = C->getLocation();
1694 
1695         if (!CallStack.empty()) {
1696           assert(CallStack.back().first == C);
1697           CallStack.pop_back();
1698         }
1699         break;
1700       }
1701 
1702       // Query the location context here and the previous location
1703       // as processing CallEnter may change the active path.
1704       PDB.LC = N->getLocationContext();
1705 
1706       // Record the mapping from the active path to the location
1707       // context.
1708       assert(!LCM[&PD.getActivePath()] ||
1709              LCM[&PD.getActivePath()] == PDB.LC);
1710       LCM[&PD.getActivePath()] = PDB.LC;
1711 
1712       // Have we encountered an exit from a function call?
1713       if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
1714         const Stmt *S = CE->getCalleeContext()->getCallSite();
1715         // Propagate the interesting symbols accordingly.
1716         if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) {
1717           reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1718                                               N->getState().get(), Ex,
1719                                               N->getLocationContext());
1720         }
1721 
1722         // We are descending into a call (backwards).  Construct
1723         // a new call piece to contain the path pieces for that call.
1724         PathDiagnosticCallPiece *C =
1725           PathDiagnosticCallPiece::construct(N, *CE, SM);
1726 
1727         // Record the location context for this call piece.
1728         LCM[&C->path] = CE->getCalleeContext();
1729 
1730         // Add the edge to the return site.
1731         addEdgeToPath(PD.getActivePath(), PrevLoc, C->callReturn, PDB.LC);
1732         PD.getActivePath().push_front(C);
1733         PrevLoc.invalidate();
1734 
1735         // Make the contents of the call the active path for now.
1736         PD.pushActivePath(&C->path);
1737         CallStack.push_back(StackDiagPair(C, N));
1738         break;
1739       }
1740 
1741       if (Optional<PostStmt> PS = P.getAs<PostStmt>()) {
1742         // For expressions, make sure we propagate the
1743         // interesting symbols correctly.
1744         if (const Expr *Ex = PS->getStmtAs<Expr>())
1745           reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1746                                               N->getState().get(), Ex,
1747                                               N->getLocationContext());
1748 
1749         // Add an edge.  If this is an ObjCForCollectionStmt do
1750         // not add an edge here as it appears in the CFG both
1751         // as a terminator and as a terminator condition.
1752         if (!isa<ObjCForCollectionStmt>(PS->getStmt())) {
1753           PathDiagnosticLocation L =
1754             PathDiagnosticLocation(PS->getStmt(), SM, PDB.LC);
1755           addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC);
1756         }
1757         break;
1758       }
1759 
1760       // Block edges.
1761       if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
1762         // Does this represent entering a call?  If so, look at propagating
1763         // interesting symbols across call boundaries.
1764         if (NextNode) {
1765           const LocationContext *CallerCtx = NextNode->getLocationContext();
1766           const LocationContext *CalleeCtx = PDB.LC;
1767           if (CallerCtx != CalleeCtx) {
1768             reversePropagateInterestingSymbols(*PDB.getBugReport(), IE,
1769                                                N->getState().get(),
1770                                                CalleeCtx, CallerCtx);
1771           }
1772         }
1773 
1774         // Are we jumping to the head of a loop?  Add a special diagnostic.
1775         if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) {
1776           PathDiagnosticLocation L(Loop, SM, PDB.LC);
1777           const Stmt *Body = nullptr;
1778 
1779           if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
1780             Body = FS->getBody();
1781           else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
1782             Body = WS->getBody();
1783           else if (const ObjCForCollectionStmt *OFS =
1784                      dyn_cast<ObjCForCollectionStmt>(Loop)) {
1785             Body = OFS->getBody();
1786           } else if (const CXXForRangeStmt *FRS =
1787                        dyn_cast<CXXForRangeStmt>(Loop)) {
1788             Body = FRS->getBody();
1789           }
1790           // do-while statements are explicitly excluded here
1791 
1792           PathDiagnosticEventPiece *p =
1793             new PathDiagnosticEventPiece(L, "Looping back to the head "
1794                                             "of the loop");
1795           p->setPrunable(true);
1796 
1797           addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC);
1798           PD.getActivePath().push_front(p);
1799 
1800           if (const CompoundStmt *CS = dyn_cast_or_null<CompoundStmt>(Body)) {
1801             addEdgeToPath(PD.getActivePath(), PrevLoc,
1802                           PathDiagnosticLocation::createEndBrace(CS, SM),
1803                           PDB.LC);
1804           }
1805         }
1806 
1807         const CFGBlock *BSrc = BE->getSrc();
1808         ParentMap &PM = PDB.getParentMap();
1809 
1810         if (const Stmt *Term = BSrc->getTerminator()) {
1811           // Are we jumping past the loop body without ever executing the
1812           // loop (because the condition was false)?
1813           if (isLoop(Term)) {
1814             const Stmt *TermCond = getTerminatorCondition(BSrc);
1815             bool IsInLoopBody =
1816               isInLoopBody(PM, getStmtBeforeCond(PM, TermCond, N), Term);
1817 
1818             const char *str = nullptr;
1819 
1820             if (isJumpToFalseBranch(&*BE)) {
1821               if (!IsInLoopBody) {
1822                 if (isa<ObjCForCollectionStmt>(Term)) {
1823                   str = StrLoopCollectionEmpty;
1824                 } else if (isa<CXXForRangeStmt>(Term)) {
1825                   str = StrLoopRangeEmpty;
1826                 } else {
1827                   str = StrLoopBodyZero;
1828                 }
1829               }
1830             } else {
1831               str = StrEnteringLoop;
1832             }
1833 
1834             if (str) {
1835               PathDiagnosticLocation L(TermCond ? TermCond : Term, SM, PDB.LC);
1836               PathDiagnosticEventPiece *PE =
1837                 new PathDiagnosticEventPiece(L, str);
1838               PE->setPrunable(true);
1839               addEdgeToPath(PD.getActivePath(), PrevLoc,
1840                             PE->getLocation(), PDB.LC);
1841               PD.getActivePath().push_front(PE);
1842             }
1843           } else if (isa<BreakStmt>(Term) || isa<ContinueStmt>(Term) ||
1844                      isa<GotoStmt>(Term)) {
1845             PathDiagnosticLocation L(Term, SM, PDB.LC);
1846             addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC);
1847           }
1848         }
1849         break;
1850       }
1851     } while (0);
1852 
1853     if (!NextNode)
1854       continue;
1855 
1856     // Add pieces from custom visitors.
1857     for (auto &V : visitors) {
1858       if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *report)) {
1859         addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC);
1860         PD.getActivePath().push_front(p);
1861         updateStackPiecesWithMessage(p, CallStack);
1862       }
1863     }
1864   }
1865 
1866   // Add an edge to the start of the function.
1867   // We'll prune it out later, but it helps make diagnostics more uniform.
1868   const StackFrameContext *CalleeLC = PDB.LC->getCurrentStackFrame();
1869   const Decl *D = CalleeLC->getDecl();
1870   addEdgeToPath(PD.getActivePath(), PrevLoc,
1871                 PathDiagnosticLocation::createBegin(D, SM),
1872                 CalleeLC);
1873 
1874   return report->isValid();
1875 }
1876 
getLocStmt(PathDiagnosticLocation L)1877 static const Stmt *getLocStmt(PathDiagnosticLocation L) {
1878   if (!L.isValid())
1879     return nullptr;
1880   return L.asStmt();
1881 }
1882 
getStmtParent(const Stmt * S,const ParentMap & PM)1883 static const Stmt *getStmtParent(const Stmt *S, const ParentMap &PM) {
1884   if (!S)
1885     return nullptr;
1886 
1887   while (true) {
1888     S = PM.getParentIgnoreParens(S);
1889 
1890     if (!S)
1891       break;
1892 
1893     if (isa<ExprWithCleanups>(S) ||
1894         isa<CXXBindTemporaryExpr>(S) ||
1895         isa<SubstNonTypeTemplateParmExpr>(S))
1896       continue;
1897 
1898     break;
1899   }
1900 
1901   return S;
1902 }
1903 
isConditionForTerminator(const Stmt * S,const Stmt * Cond)1904 static bool isConditionForTerminator(const Stmt *S, const Stmt *Cond) {
1905   switch (S->getStmtClass()) {
1906     case Stmt::BinaryOperatorClass: {
1907       const BinaryOperator *BO = cast<BinaryOperator>(S);
1908       if (!BO->isLogicalOp())
1909         return false;
1910       return BO->getLHS() == Cond || BO->getRHS() == Cond;
1911     }
1912     case Stmt::IfStmtClass:
1913       return cast<IfStmt>(S)->getCond() == Cond;
1914     case Stmt::ForStmtClass:
1915       return cast<ForStmt>(S)->getCond() == Cond;
1916     case Stmt::WhileStmtClass:
1917       return cast<WhileStmt>(S)->getCond() == Cond;
1918     case Stmt::DoStmtClass:
1919       return cast<DoStmt>(S)->getCond() == Cond;
1920     case Stmt::ChooseExprClass:
1921       return cast<ChooseExpr>(S)->getCond() == Cond;
1922     case Stmt::IndirectGotoStmtClass:
1923       return cast<IndirectGotoStmt>(S)->getTarget() == Cond;
1924     case Stmt::SwitchStmtClass:
1925       return cast<SwitchStmt>(S)->getCond() == Cond;
1926     case Stmt::BinaryConditionalOperatorClass:
1927       return cast<BinaryConditionalOperator>(S)->getCond() == Cond;
1928     case Stmt::ConditionalOperatorClass: {
1929       const ConditionalOperator *CO = cast<ConditionalOperator>(S);
1930       return CO->getCond() == Cond ||
1931              CO->getLHS() == Cond ||
1932              CO->getRHS() == Cond;
1933     }
1934     case Stmt::ObjCForCollectionStmtClass:
1935       return cast<ObjCForCollectionStmt>(S)->getElement() == Cond;
1936     case Stmt::CXXForRangeStmtClass: {
1937       const CXXForRangeStmt *FRS = cast<CXXForRangeStmt>(S);
1938       return FRS->getCond() == Cond || FRS->getRangeInit() == Cond;
1939     }
1940     default:
1941       return false;
1942   }
1943 }
1944 
isIncrementOrInitInForLoop(const Stmt * S,const Stmt * FL)1945 static bool isIncrementOrInitInForLoop(const Stmt *S, const Stmt *FL) {
1946   if (const ForStmt *FS = dyn_cast<ForStmt>(FL))
1947     return FS->getInc() == S || FS->getInit() == S;
1948   if (const CXXForRangeStmt *FRS = dyn_cast<CXXForRangeStmt>(FL))
1949     return FRS->getInc() == S || FRS->getRangeStmt() == S ||
1950            FRS->getLoopVarStmt() || FRS->getRangeInit() == S;
1951   return false;
1952 }
1953 
1954 typedef llvm::DenseSet<const PathDiagnosticCallPiece *>
1955         OptimizedCallsSet;
1956 
1957 /// Adds synthetic edges from top-level statements to their subexpressions.
1958 ///
1959 /// This avoids a "swoosh" effect, where an edge from a top-level statement A
1960 /// points to a sub-expression B.1 that's not at the start of B. In these cases,
1961 /// we'd like to see an edge from A to B, then another one from B to B.1.
addContextEdges(PathPieces & pieces,SourceManager & SM,const ParentMap & PM,const LocationContext * LCtx)1962 static void addContextEdges(PathPieces &pieces, SourceManager &SM,
1963                             const ParentMap &PM, const LocationContext *LCtx) {
1964   PathPieces::iterator Prev = pieces.end();
1965   for (PathPieces::iterator I = pieces.begin(), E = Prev; I != E;
1966        Prev = I, ++I) {
1967     PathDiagnosticControlFlowPiece *Piece =
1968       dyn_cast<PathDiagnosticControlFlowPiece>(*I);
1969 
1970     if (!Piece)
1971       continue;
1972 
1973     PathDiagnosticLocation SrcLoc = Piece->getStartLocation();
1974     SmallVector<PathDiagnosticLocation, 4> SrcContexts;
1975 
1976     PathDiagnosticLocation NextSrcContext = SrcLoc;
1977     const Stmt *InnerStmt = nullptr;
1978     while (NextSrcContext.isValid() && NextSrcContext.asStmt() != InnerStmt) {
1979       SrcContexts.push_back(NextSrcContext);
1980       InnerStmt = NextSrcContext.asStmt();
1981       NextSrcContext = getEnclosingStmtLocation(InnerStmt, SM, PM, LCtx,
1982                                                 /*allowNested=*/true);
1983     }
1984 
1985     // Repeatedly split the edge as necessary.
1986     // This is important for nested logical expressions (||, &&, ?:) where we
1987     // want to show all the levels of context.
1988     while (true) {
1989       const Stmt *Dst = getLocStmt(Piece->getEndLocation());
1990 
1991       // We are looking at an edge. Is the destination within a larger
1992       // expression?
1993       PathDiagnosticLocation DstContext =
1994         getEnclosingStmtLocation(Dst, SM, PM, LCtx, /*allowNested=*/true);
1995       if (!DstContext.isValid() || DstContext.asStmt() == Dst)
1996         break;
1997 
1998       // If the source is in the same context, we're already good.
1999       if (std::find(SrcContexts.begin(), SrcContexts.end(), DstContext) !=
2000           SrcContexts.end())
2001         break;
2002 
2003       // Update the subexpression node to point to the context edge.
2004       Piece->setStartLocation(DstContext);
2005 
2006       // Try to extend the previous edge if it's at the same level as the source
2007       // context.
2008       if (Prev != E) {
2009         PathDiagnosticControlFlowPiece *PrevPiece =
2010           dyn_cast<PathDiagnosticControlFlowPiece>(*Prev);
2011 
2012         if (PrevPiece) {
2013           if (const Stmt *PrevSrc = getLocStmt(PrevPiece->getStartLocation())) {
2014             const Stmt *PrevSrcParent = getStmtParent(PrevSrc, PM);
2015             if (PrevSrcParent == getStmtParent(getLocStmt(DstContext), PM)) {
2016               PrevPiece->setEndLocation(DstContext);
2017               break;
2018             }
2019           }
2020         }
2021       }
2022 
2023       // Otherwise, split the current edge into a context edge and a
2024       // subexpression edge. Note that the context statement may itself have
2025       // context.
2026       Piece = new PathDiagnosticControlFlowPiece(SrcLoc, DstContext);
2027       I = pieces.insert(I, Piece);
2028     }
2029   }
2030 }
2031 
2032 /// \brief Move edges from a branch condition to a branch target
2033 ///        when the condition is simple.
2034 ///
2035 /// This restructures some of the work of addContextEdges.  That function
2036 /// creates edges this may destroy, but they work together to create a more
2037 /// aesthetically set of edges around branches.  After the call to
2038 /// addContextEdges, we may have (1) an edge to the branch, (2) an edge from
2039 /// the branch to the branch condition, and (3) an edge from the branch
2040 /// condition to the branch target.  We keep (1), but may wish to remove (2)
2041 /// and move the source of (3) to the branch if the branch condition is simple.
2042 ///
simplifySimpleBranches(PathPieces & pieces)2043 static void simplifySimpleBranches(PathPieces &pieces) {
2044   for (PathPieces::iterator I = pieces.begin(), E = pieces.end(); I != E; ++I) {
2045 
2046     PathDiagnosticControlFlowPiece *PieceI =
2047       dyn_cast<PathDiagnosticControlFlowPiece>(*I);
2048 
2049     if (!PieceI)
2050       continue;
2051 
2052     const Stmt *s1Start = getLocStmt(PieceI->getStartLocation());
2053     const Stmt *s1End   = getLocStmt(PieceI->getEndLocation());
2054 
2055     if (!s1Start || !s1End)
2056       continue;
2057 
2058     PathPieces::iterator NextI = I; ++NextI;
2059     if (NextI == E)
2060       break;
2061 
2062     PathDiagnosticControlFlowPiece *PieceNextI = nullptr;
2063 
2064     while (true) {
2065       if (NextI == E)
2066         break;
2067 
2068       PathDiagnosticEventPiece *EV = dyn_cast<PathDiagnosticEventPiece>(*NextI);
2069       if (EV) {
2070         StringRef S = EV->getString();
2071         if (S == StrEnteringLoop || S == StrLoopBodyZero ||
2072             S == StrLoopCollectionEmpty || S == StrLoopRangeEmpty) {
2073           ++NextI;
2074           continue;
2075         }
2076         break;
2077       }
2078 
2079       PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(*NextI);
2080       break;
2081     }
2082 
2083     if (!PieceNextI)
2084       continue;
2085 
2086     const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation());
2087     const Stmt *s2End   = getLocStmt(PieceNextI->getEndLocation());
2088 
2089     if (!s2Start || !s2End || s1End != s2Start)
2090       continue;
2091 
2092     // We only perform this transformation for specific branch kinds.
2093     // We don't want to do this for do..while, for example.
2094     if (!(isa<ForStmt>(s1Start) || isa<WhileStmt>(s1Start) ||
2095           isa<IfStmt>(s1Start) || isa<ObjCForCollectionStmt>(s1Start) ||
2096           isa<CXXForRangeStmt>(s1Start)))
2097       continue;
2098 
2099     // Is s1End the branch condition?
2100     if (!isConditionForTerminator(s1Start, s1End))
2101       continue;
2102 
2103     // Perform the hoisting by eliminating (2) and changing the start
2104     // location of (3).
2105     PieceNextI->setStartLocation(PieceI->getStartLocation());
2106     I = pieces.erase(I);
2107   }
2108 }
2109 
2110 /// Returns the number of bytes in the given (character-based) SourceRange.
2111 ///
2112 /// If the locations in the range are not on the same line, returns None.
2113 ///
2114 /// Note that this does not do a precise user-visible character or column count.
getLengthOnSingleLine(SourceManager & SM,SourceRange Range)2115 static Optional<size_t> getLengthOnSingleLine(SourceManager &SM,
2116                                               SourceRange Range) {
2117   SourceRange ExpansionRange(SM.getExpansionLoc(Range.getBegin()),
2118                              SM.getExpansionRange(Range.getEnd()).second);
2119 
2120   FileID FID = SM.getFileID(ExpansionRange.getBegin());
2121   if (FID != SM.getFileID(ExpansionRange.getEnd()))
2122     return None;
2123 
2124   bool Invalid;
2125   const llvm::MemoryBuffer *Buffer = SM.getBuffer(FID, &Invalid);
2126   if (Invalid)
2127     return None;
2128 
2129   unsigned BeginOffset = SM.getFileOffset(ExpansionRange.getBegin());
2130   unsigned EndOffset = SM.getFileOffset(ExpansionRange.getEnd());
2131   StringRef Snippet = Buffer->getBuffer().slice(BeginOffset, EndOffset);
2132 
2133   // We're searching the raw bytes of the buffer here, which might include
2134   // escaped newlines and such. That's okay; we're trying to decide whether the
2135   // SourceRange is covering a large or small amount of space in the user's
2136   // editor.
2137   if (Snippet.find_first_of("\r\n") != StringRef::npos)
2138     return None;
2139 
2140   // This isn't Unicode-aware, but it doesn't need to be.
2141   return Snippet.size();
2142 }
2143 
2144 /// \sa getLengthOnSingleLine(SourceManager, SourceRange)
getLengthOnSingleLine(SourceManager & SM,const Stmt * S)2145 static Optional<size_t> getLengthOnSingleLine(SourceManager &SM,
2146                                               const Stmt *S) {
2147   return getLengthOnSingleLine(SM, S->getSourceRange());
2148 }
2149 
2150 /// Eliminate two-edge cycles created by addContextEdges().
2151 ///
2152 /// Once all the context edges are in place, there are plenty of cases where
2153 /// there's a single edge from a top-level statement to a subexpression,
2154 /// followed by a single path note, and then a reverse edge to get back out to
2155 /// the top level. If the statement is simple enough, the subexpression edges
2156 /// just add noise and make it harder to understand what's going on.
2157 ///
2158 /// This function only removes edges in pairs, because removing only one edge
2159 /// might leave other edges dangling.
2160 ///
2161 /// This will not remove edges in more complicated situations:
2162 /// - if there is more than one "hop" leading to or from a subexpression.
2163 /// - if there is an inlined call between the edges instead of a single event.
2164 /// - if the whole statement is large enough that having subexpression arrows
2165 ///   might be helpful.
removeContextCycles(PathPieces & Path,SourceManager & SM,ParentMap & PM)2166 static void removeContextCycles(PathPieces &Path, SourceManager &SM,
2167                                 ParentMap &PM) {
2168   for (PathPieces::iterator I = Path.begin(), E = Path.end(); I != E; ) {
2169     // Pattern match the current piece and its successor.
2170     PathDiagnosticControlFlowPiece *PieceI =
2171       dyn_cast<PathDiagnosticControlFlowPiece>(*I);
2172 
2173     if (!PieceI) {
2174       ++I;
2175       continue;
2176     }
2177 
2178     const Stmt *s1Start = getLocStmt(PieceI->getStartLocation());
2179     const Stmt *s1End   = getLocStmt(PieceI->getEndLocation());
2180 
2181     PathPieces::iterator NextI = I; ++NextI;
2182     if (NextI == E)
2183       break;
2184 
2185     PathDiagnosticControlFlowPiece *PieceNextI =
2186       dyn_cast<PathDiagnosticControlFlowPiece>(*NextI);
2187 
2188     if (!PieceNextI) {
2189       if (isa<PathDiagnosticEventPiece>(*NextI)) {
2190         ++NextI;
2191         if (NextI == E)
2192           break;
2193         PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(*NextI);
2194       }
2195 
2196       if (!PieceNextI) {
2197         ++I;
2198         continue;
2199       }
2200     }
2201 
2202     const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation());
2203     const Stmt *s2End   = getLocStmt(PieceNextI->getEndLocation());
2204 
2205     if (s1Start && s2Start && s1Start == s2End && s2Start == s1End) {
2206       const size_t MAX_SHORT_LINE_LENGTH = 80;
2207       Optional<size_t> s1Length = getLengthOnSingleLine(SM, s1Start);
2208       if (s1Length && *s1Length <= MAX_SHORT_LINE_LENGTH) {
2209         Optional<size_t> s2Length = getLengthOnSingleLine(SM, s2Start);
2210         if (s2Length && *s2Length <= MAX_SHORT_LINE_LENGTH) {
2211           Path.erase(I);
2212           I = Path.erase(NextI);
2213           continue;
2214         }
2215       }
2216     }
2217 
2218     ++I;
2219   }
2220 }
2221 
2222 /// \brief Return true if X is contained by Y.
lexicalContains(ParentMap & PM,const Stmt * X,const Stmt * Y)2223 static bool lexicalContains(ParentMap &PM,
2224                             const Stmt *X,
2225                             const Stmt *Y) {
2226   while (X) {
2227     if (X == Y)
2228       return true;
2229     X = PM.getParent(X);
2230   }
2231   return false;
2232 }
2233 
2234 // Remove short edges on the same line less than 3 columns in difference.
removePunyEdges(PathPieces & path,SourceManager & SM,ParentMap & PM)2235 static void removePunyEdges(PathPieces &path,
2236                             SourceManager &SM,
2237                             ParentMap &PM) {
2238 
2239   bool erased = false;
2240 
2241   for (PathPieces::iterator I = path.begin(), E = path.end(); I != E;
2242        erased ? I : ++I) {
2243 
2244     erased = false;
2245 
2246     PathDiagnosticControlFlowPiece *PieceI =
2247       dyn_cast<PathDiagnosticControlFlowPiece>(*I);
2248 
2249     if (!PieceI)
2250       continue;
2251 
2252     const Stmt *start = getLocStmt(PieceI->getStartLocation());
2253     const Stmt *end   = getLocStmt(PieceI->getEndLocation());
2254 
2255     if (!start || !end)
2256       continue;
2257 
2258     const Stmt *endParent = PM.getParent(end);
2259     if (!endParent)
2260       continue;
2261 
2262     if (isConditionForTerminator(end, endParent))
2263       continue;
2264 
2265     SourceLocation FirstLoc = start->getLocStart();
2266     SourceLocation SecondLoc = end->getLocStart();
2267 
2268     if (!SM.isWrittenInSameFile(FirstLoc, SecondLoc))
2269       continue;
2270     if (SM.isBeforeInTranslationUnit(SecondLoc, FirstLoc))
2271       std::swap(SecondLoc, FirstLoc);
2272 
2273     SourceRange EdgeRange(FirstLoc, SecondLoc);
2274     Optional<size_t> ByteWidth = getLengthOnSingleLine(SM, EdgeRange);
2275 
2276     // If the statements are on different lines, continue.
2277     if (!ByteWidth)
2278       continue;
2279 
2280     const size_t MAX_PUNY_EDGE_LENGTH = 2;
2281     if (*ByteWidth <= MAX_PUNY_EDGE_LENGTH) {
2282       // FIXME: There are enough /bytes/ between the endpoints of the edge, but
2283       // there might not be enough /columns/. A proper user-visible column count
2284       // is probably too expensive, though.
2285       I = path.erase(I);
2286       erased = true;
2287       continue;
2288     }
2289   }
2290 }
2291 
removeIdenticalEvents(PathPieces & path)2292 static void removeIdenticalEvents(PathPieces &path) {
2293   for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ++I) {
2294     PathDiagnosticEventPiece *PieceI =
2295       dyn_cast<PathDiagnosticEventPiece>(*I);
2296 
2297     if (!PieceI)
2298       continue;
2299 
2300     PathPieces::iterator NextI = I; ++NextI;
2301     if (NextI == E)
2302       return;
2303 
2304     PathDiagnosticEventPiece *PieceNextI =
2305       dyn_cast<PathDiagnosticEventPiece>(*NextI);
2306 
2307     if (!PieceNextI)
2308       continue;
2309 
2310     // Erase the second piece if it has the same exact message text.
2311     if (PieceI->getString() == PieceNextI->getString()) {
2312       path.erase(NextI);
2313     }
2314   }
2315 }
2316 
optimizeEdges(PathPieces & path,SourceManager & SM,OptimizedCallsSet & OCS,LocationContextMap & LCM)2317 static bool optimizeEdges(PathPieces &path, SourceManager &SM,
2318                           OptimizedCallsSet &OCS,
2319                           LocationContextMap &LCM) {
2320   bool hasChanges = false;
2321   const LocationContext *LC = LCM[&path];
2322   assert(LC);
2323   ParentMap &PM = LC->getParentMap();
2324 
2325   for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ) {
2326     // Optimize subpaths.
2327     if (PathDiagnosticCallPiece *CallI = dyn_cast<PathDiagnosticCallPiece>(*I)){
2328       // Record the fact that a call has been optimized so we only do the
2329       // effort once.
2330       if (!OCS.count(CallI)) {
2331         while (optimizeEdges(CallI->path, SM, OCS, LCM)) {}
2332         OCS.insert(CallI);
2333       }
2334       ++I;
2335       continue;
2336     }
2337 
2338     // Pattern match the current piece and its successor.
2339     PathDiagnosticControlFlowPiece *PieceI =
2340       dyn_cast<PathDiagnosticControlFlowPiece>(*I);
2341 
2342     if (!PieceI) {
2343       ++I;
2344       continue;
2345     }
2346 
2347     const Stmt *s1Start = getLocStmt(PieceI->getStartLocation());
2348     const Stmt *s1End   = getLocStmt(PieceI->getEndLocation());
2349     const Stmt *level1 = getStmtParent(s1Start, PM);
2350     const Stmt *level2 = getStmtParent(s1End, PM);
2351 
2352     PathPieces::iterator NextI = I; ++NextI;
2353     if (NextI == E)
2354       break;
2355 
2356     PathDiagnosticControlFlowPiece *PieceNextI =
2357       dyn_cast<PathDiagnosticControlFlowPiece>(*NextI);
2358 
2359     if (!PieceNextI) {
2360       ++I;
2361       continue;
2362     }
2363 
2364     const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation());
2365     const Stmt *s2End   = getLocStmt(PieceNextI->getEndLocation());
2366     const Stmt *level3 = getStmtParent(s2Start, PM);
2367     const Stmt *level4 = getStmtParent(s2End, PM);
2368 
2369     // Rule I.
2370     //
2371     // If we have two consecutive control edges whose end/begin locations
2372     // are at the same level (e.g. statements or top-level expressions within
2373     // a compound statement, or siblings share a single ancestor expression),
2374     // then merge them if they have no interesting intermediate event.
2375     //
2376     // For example:
2377     //
2378     // (1.1 -> 1.2) -> (1.2 -> 1.3) becomes (1.1 -> 1.3) because the common
2379     // parent is '1'.  Here 'x.y.z' represents the hierarchy of statements.
2380     //
2381     // NOTE: this will be limited later in cases where we add barriers
2382     // to prevent this optimization.
2383     //
2384     if (level1 && level1 == level2 && level1 == level3 && level1 == level4) {
2385       PieceI->setEndLocation(PieceNextI->getEndLocation());
2386       path.erase(NextI);
2387       hasChanges = true;
2388       continue;
2389     }
2390 
2391     // Rule II.
2392     //
2393     // Eliminate edges between subexpressions and parent expressions
2394     // when the subexpression is consumed.
2395     //
2396     // NOTE: this will be limited later in cases where we add barriers
2397     // to prevent this optimization.
2398     //
2399     if (s1End && s1End == s2Start && level2) {
2400       bool removeEdge = false;
2401       // Remove edges into the increment or initialization of a
2402       // loop that have no interleaving event.  This means that
2403       // they aren't interesting.
2404       if (isIncrementOrInitInForLoop(s1End, level2))
2405         removeEdge = true;
2406       // Next only consider edges that are not anchored on
2407       // the condition of a terminator.  This are intermediate edges
2408       // that we might want to trim.
2409       else if (!isConditionForTerminator(level2, s1End)) {
2410         // Trim edges on expressions that are consumed by
2411         // the parent expression.
2412         if (isa<Expr>(s1End) && PM.isConsumedExpr(cast<Expr>(s1End))) {
2413           removeEdge = true;
2414         }
2415         // Trim edges where a lexical containment doesn't exist.
2416         // For example:
2417         //
2418         //  X -> Y -> Z
2419         //
2420         // If 'Z' lexically contains Y (it is an ancestor) and
2421         // 'X' does not lexically contain Y (it is a descendant OR
2422         // it has no lexical relationship at all) then trim.
2423         //
2424         // This can eliminate edges where we dive into a subexpression
2425         // and then pop back out, etc.
2426         else if (s1Start && s2End &&
2427                  lexicalContains(PM, s2Start, s2End) &&
2428                  !lexicalContains(PM, s1End, s1Start)) {
2429           removeEdge = true;
2430         }
2431         // Trim edges from a subexpression back to the top level if the
2432         // subexpression is on a different line.
2433         //
2434         // A.1 -> A -> B
2435         // becomes
2436         // A.1 -> B
2437         //
2438         // These edges just look ugly and don't usually add anything.
2439         else if (s1Start && s2End &&
2440                  lexicalContains(PM, s1Start, s1End)) {
2441           SourceRange EdgeRange(PieceI->getEndLocation().asLocation(),
2442                                 PieceI->getStartLocation().asLocation());
2443           if (!getLengthOnSingleLine(SM, EdgeRange).hasValue())
2444             removeEdge = true;
2445         }
2446       }
2447 
2448       if (removeEdge) {
2449         PieceI->setEndLocation(PieceNextI->getEndLocation());
2450         path.erase(NextI);
2451         hasChanges = true;
2452         continue;
2453       }
2454     }
2455 
2456     // Optimize edges for ObjC fast-enumeration loops.
2457     //
2458     // (X -> collection) -> (collection -> element)
2459     //
2460     // becomes:
2461     //
2462     // (X -> element)
2463     if (s1End == s2Start) {
2464       const ObjCForCollectionStmt *FS =
2465         dyn_cast_or_null<ObjCForCollectionStmt>(level3);
2466       if (FS && FS->getCollection()->IgnoreParens() == s2Start &&
2467           s2End == FS->getElement()) {
2468         PieceI->setEndLocation(PieceNextI->getEndLocation());
2469         path.erase(NextI);
2470         hasChanges = true;
2471         continue;
2472       }
2473     }
2474 
2475     // No changes at this index?  Move to the next one.
2476     ++I;
2477   }
2478 
2479   if (!hasChanges) {
2480     // Adjust edges into subexpressions to make them more uniform
2481     // and aesthetically pleasing.
2482     addContextEdges(path, SM, PM, LC);
2483     // Remove "cyclical" edges that include one or more context edges.
2484     removeContextCycles(path, SM, PM);
2485     // Hoist edges originating from branch conditions to branches
2486     // for simple branches.
2487     simplifySimpleBranches(path);
2488     // Remove any puny edges left over after primary optimization pass.
2489     removePunyEdges(path, SM, PM);
2490     // Remove identical events.
2491     removeIdenticalEvents(path);
2492   }
2493 
2494   return hasChanges;
2495 }
2496 
2497 /// Drop the very first edge in a path, which should be a function entry edge.
2498 ///
2499 /// If the first edge is not a function entry edge (say, because the first
2500 /// statement had an invalid source location), this function does nothing.
2501 // FIXME: We should just generate invalid edges anyway and have the optimizer
2502 // deal with them.
dropFunctionEntryEdge(PathPieces & Path,LocationContextMap & LCM,SourceManager & SM)2503 static void dropFunctionEntryEdge(PathPieces &Path,
2504                                   LocationContextMap &LCM,
2505                                   SourceManager &SM) {
2506   const PathDiagnosticControlFlowPiece *FirstEdge =
2507     dyn_cast<PathDiagnosticControlFlowPiece>(Path.front());
2508   if (!FirstEdge)
2509     return;
2510 
2511   const Decl *D = LCM[&Path]->getDecl();
2512   PathDiagnosticLocation EntryLoc = PathDiagnosticLocation::createBegin(D, SM);
2513   if (FirstEdge->getStartLocation() != EntryLoc)
2514     return;
2515 
2516   Path.pop_front();
2517 }
2518 
2519 
2520 //===----------------------------------------------------------------------===//
2521 // Methods for BugType and subclasses.
2522 //===----------------------------------------------------------------------===//
anchor()2523 void BugType::anchor() { }
2524 
FlushReports(BugReporter & BR)2525 void BugType::FlushReports(BugReporter &BR) {}
2526 
anchor()2527 void BuiltinBug::anchor() {}
2528 
2529 //===----------------------------------------------------------------------===//
2530 // Methods for BugReport and subclasses.
2531 //===----------------------------------------------------------------------===//
2532 
anchor()2533 void BugReport::NodeResolver::anchor() {}
2534 
addVisitor(std::unique_ptr<BugReporterVisitor> visitor)2535 void BugReport::addVisitor(std::unique_ptr<BugReporterVisitor> visitor) {
2536   if (!visitor)
2537     return;
2538 
2539   llvm::FoldingSetNodeID ID;
2540   visitor->Profile(ID);
2541   void *InsertPos;
2542 
2543   if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos))
2544     return;
2545 
2546   CallbacksSet.InsertNode(visitor.get(), InsertPos);
2547   Callbacks.push_back(std::move(visitor));
2548   ++ConfigurationChangeToken;
2549 }
2550 
~BugReport()2551 BugReport::~BugReport() {
2552   while (!interestingSymbols.empty()) {
2553     popInterestingSymbolsAndRegions();
2554   }
2555 }
2556 
getDeclWithIssue() const2557 const Decl *BugReport::getDeclWithIssue() const {
2558   if (DeclWithIssue)
2559     return DeclWithIssue;
2560 
2561   const ExplodedNode *N = getErrorNode();
2562   if (!N)
2563     return nullptr;
2564 
2565   const LocationContext *LC = N->getLocationContext();
2566   return LC->getCurrentStackFrame()->getDecl();
2567 }
2568 
Profile(llvm::FoldingSetNodeID & hash) const2569 void BugReport::Profile(llvm::FoldingSetNodeID& hash) const {
2570   hash.AddPointer(&BT);
2571   hash.AddString(Description);
2572   PathDiagnosticLocation UL = getUniqueingLocation();
2573   if (UL.isValid()) {
2574     UL.Profile(hash);
2575   } else if (Location.isValid()) {
2576     Location.Profile(hash);
2577   } else {
2578     assert(ErrorNode);
2579     hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode));
2580   }
2581 
2582   for (SourceRange range : Ranges) {
2583     if (!range.isValid())
2584       continue;
2585     hash.AddInteger(range.getBegin().getRawEncoding());
2586     hash.AddInteger(range.getEnd().getRawEncoding());
2587   }
2588 }
2589 
markInteresting(SymbolRef sym)2590 void BugReport::markInteresting(SymbolRef sym) {
2591   if (!sym)
2592     return;
2593 
2594   // If the symbol wasn't already in our set, note a configuration change.
2595   if (getInterestingSymbols().insert(sym).second)
2596     ++ConfigurationChangeToken;
2597 
2598   if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym))
2599     getInterestingRegions().insert(meta->getRegion());
2600 }
2601 
markInteresting(const MemRegion * R)2602 void BugReport::markInteresting(const MemRegion *R) {
2603   if (!R)
2604     return;
2605 
2606   // If the base region wasn't already in our set, note a configuration change.
2607   R = R->getBaseRegion();
2608   if (getInterestingRegions().insert(R).second)
2609     ++ConfigurationChangeToken;
2610 
2611   if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
2612     getInterestingSymbols().insert(SR->getSymbol());
2613 }
2614 
markInteresting(SVal V)2615 void BugReport::markInteresting(SVal V) {
2616   markInteresting(V.getAsRegion());
2617   markInteresting(V.getAsSymbol());
2618 }
2619 
markInteresting(const LocationContext * LC)2620 void BugReport::markInteresting(const LocationContext *LC) {
2621   if (!LC)
2622     return;
2623   InterestingLocationContexts.insert(LC);
2624 }
2625 
isInteresting(SVal V)2626 bool BugReport::isInteresting(SVal V) {
2627   return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol());
2628 }
2629 
isInteresting(SymbolRef sym)2630 bool BugReport::isInteresting(SymbolRef sym) {
2631   if (!sym)
2632     return false;
2633   // We don't currently consider metadata symbols to be interesting
2634   // even if we know their region is interesting. Is that correct behavior?
2635   return getInterestingSymbols().count(sym);
2636 }
2637 
isInteresting(const MemRegion * R)2638 bool BugReport::isInteresting(const MemRegion *R) {
2639   if (!R)
2640     return false;
2641   R = R->getBaseRegion();
2642   bool b = getInterestingRegions().count(R);
2643   if (b)
2644     return true;
2645   if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
2646     return getInterestingSymbols().count(SR->getSymbol());
2647   return false;
2648 }
2649 
isInteresting(const LocationContext * LC)2650 bool BugReport::isInteresting(const LocationContext *LC) {
2651   if (!LC)
2652     return false;
2653   return InterestingLocationContexts.count(LC);
2654 }
2655 
lazyInitializeInterestingSets()2656 void BugReport::lazyInitializeInterestingSets() {
2657   if (interestingSymbols.empty()) {
2658     interestingSymbols.push_back(new Symbols());
2659     interestingRegions.push_back(new Regions());
2660   }
2661 }
2662 
getInterestingSymbols()2663 BugReport::Symbols &BugReport::getInterestingSymbols() {
2664   lazyInitializeInterestingSets();
2665   return *interestingSymbols.back();
2666 }
2667 
getInterestingRegions()2668 BugReport::Regions &BugReport::getInterestingRegions() {
2669   lazyInitializeInterestingSets();
2670   return *interestingRegions.back();
2671 }
2672 
pushInterestingSymbolsAndRegions()2673 void BugReport::pushInterestingSymbolsAndRegions() {
2674   interestingSymbols.push_back(new Symbols(getInterestingSymbols()));
2675   interestingRegions.push_back(new Regions(getInterestingRegions()));
2676 }
2677 
popInterestingSymbolsAndRegions()2678 void BugReport::popInterestingSymbolsAndRegions() {
2679   delete interestingSymbols.pop_back_val();
2680   delete interestingRegions.pop_back_val();
2681 }
2682 
getStmt() const2683 const Stmt *BugReport::getStmt() const {
2684   if (!ErrorNode)
2685     return nullptr;
2686 
2687   ProgramPoint ProgP = ErrorNode->getLocation();
2688   const Stmt *S = nullptr;
2689 
2690   if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) {
2691     CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit();
2692     if (BE->getBlock() == &Exit)
2693       S = GetPreviousStmt(ErrorNode);
2694   }
2695   if (!S)
2696     S = PathDiagnosticLocation::getStmt(ErrorNode);
2697 
2698   return S;
2699 }
2700 
getRanges()2701 llvm::iterator_range<BugReport::ranges_iterator> BugReport::getRanges() {
2702   // If no custom ranges, add the range of the statement corresponding to
2703   // the error node.
2704   if (Ranges.empty()) {
2705     if (const Expr *E = dyn_cast_or_null<Expr>(getStmt()))
2706       addRange(E->getSourceRange());
2707     else
2708       return llvm::make_range(ranges_iterator(), ranges_iterator());
2709   }
2710 
2711   // User-specified absence of range info.
2712   if (Ranges.size() == 1 && !Ranges.begin()->isValid())
2713     return llvm::make_range(ranges_iterator(), ranges_iterator());
2714 
2715   return llvm::make_range(Ranges.begin(), Ranges.end());
2716 }
2717 
getLocation(const SourceManager & SM) const2718 PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const {
2719   if (ErrorNode) {
2720     assert(!Location.isValid() &&
2721      "Either Location or ErrorNode should be specified but not both.");
2722     return PathDiagnosticLocation::createEndOfPath(ErrorNode, SM);
2723   }
2724 
2725   assert(Location.isValid());
2726   return Location;
2727 }
2728 
2729 //===----------------------------------------------------------------------===//
2730 // Methods for BugReporter and subclasses.
2731 //===----------------------------------------------------------------------===//
2732 
~BugReportEquivClass()2733 BugReportEquivClass::~BugReportEquivClass() { }
~GRBugReporter()2734 GRBugReporter::~GRBugReporter() { }
~BugReporterData()2735 BugReporterData::~BugReporterData() {}
2736 
getGraph()2737 ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); }
2738 
2739 ProgramStateManager&
getStateManager()2740 GRBugReporter::getStateManager() { return Eng.getStateManager(); }
2741 
~BugReporter()2742 BugReporter::~BugReporter() {
2743   FlushReports();
2744 
2745   // Free the bug reports we are tracking.
2746   typedef std::vector<BugReportEquivClass *> ContTy;
2747   for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end();
2748        I != E; ++I) {
2749     delete *I;
2750   }
2751 }
2752 
FlushReports()2753 void BugReporter::FlushReports() {
2754   if (BugTypes.isEmpty())
2755     return;
2756 
2757   // First flush the warnings for each BugType.  This may end up creating new
2758   // warnings and new BugTypes.
2759   // FIXME: Only NSErrorChecker needs BugType's FlushReports.
2760   // Turn NSErrorChecker into a proper checker and remove this.
2761   SmallVector<const BugType *, 16> bugTypes(BugTypes.begin(), BugTypes.end());
2762   for (SmallVectorImpl<const BugType *>::iterator
2763          I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I)
2764     const_cast<BugType*>(*I)->FlushReports(*this);
2765 
2766   // We need to flush reports in deterministic order to ensure the order
2767   // of the reports is consistent between runs.
2768   typedef std::vector<BugReportEquivClass *> ContVecTy;
2769   for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end();
2770        EI != EE; ++EI){
2771     BugReportEquivClass& EQ = **EI;
2772     FlushReport(EQ);
2773   }
2774 
2775   // BugReporter owns and deletes only BugTypes created implicitly through
2776   // EmitBasicReport.
2777   // FIXME: There are leaks from checkers that assume that the BugTypes they
2778   // create will be destroyed by the BugReporter.
2779   llvm::DeleteContainerSeconds(StrBugTypes);
2780 
2781   // Remove all references to the BugType objects.
2782   BugTypes = F.getEmptySet();
2783 }
2784 
2785 //===----------------------------------------------------------------------===//
2786 // PathDiagnostics generation.
2787 //===----------------------------------------------------------------------===//
2788 
2789 namespace {
2790 /// A wrapper around a report graph, which contains only a single path, and its
2791 /// node maps.
2792 class ReportGraph {
2793 public:
2794   InterExplodedGraphMap BackMap;
2795   std::unique_ptr<ExplodedGraph> Graph;
2796   const ExplodedNode *ErrorNode;
2797   size_t Index;
2798 };
2799 
2800 /// A wrapper around a trimmed graph and its node maps.
2801 class TrimmedGraph {
2802   InterExplodedGraphMap InverseMap;
2803 
2804   typedef llvm::DenseMap<const ExplodedNode *, unsigned> PriorityMapTy;
2805   PriorityMapTy PriorityMap;
2806 
2807   typedef std::pair<const ExplodedNode *, size_t> NodeIndexPair;
2808   SmallVector<NodeIndexPair, 32> ReportNodes;
2809 
2810   std::unique_ptr<ExplodedGraph> G;
2811 
2812   /// A helper class for sorting ExplodedNodes by priority.
2813   template <bool Descending>
2814   class PriorityCompare {
2815     const PriorityMapTy &PriorityMap;
2816 
2817   public:
PriorityCompare(const PriorityMapTy & M)2818     PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {}
2819 
operator ()(const ExplodedNode * LHS,const ExplodedNode * RHS) const2820     bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const {
2821       PriorityMapTy::const_iterator LI = PriorityMap.find(LHS);
2822       PriorityMapTy::const_iterator RI = PriorityMap.find(RHS);
2823       PriorityMapTy::const_iterator E = PriorityMap.end();
2824 
2825       if (LI == E)
2826         return Descending;
2827       if (RI == E)
2828         return !Descending;
2829 
2830       return Descending ? LI->second > RI->second
2831                         : LI->second < RI->second;
2832     }
2833 
operator ()(const NodeIndexPair & LHS,const NodeIndexPair & RHS) const2834     bool operator()(const NodeIndexPair &LHS, const NodeIndexPair &RHS) const {
2835       return (*this)(LHS.first, RHS.first);
2836     }
2837   };
2838 
2839 public:
2840   TrimmedGraph(const ExplodedGraph *OriginalGraph,
2841                ArrayRef<const ExplodedNode *> Nodes);
2842 
2843   bool popNextReportGraph(ReportGraph &GraphWrapper);
2844 };
2845 }
2846 
TrimmedGraph(const ExplodedGraph * OriginalGraph,ArrayRef<const ExplodedNode * > Nodes)2847 TrimmedGraph::TrimmedGraph(const ExplodedGraph *OriginalGraph,
2848                            ArrayRef<const ExplodedNode *> Nodes) {
2849   // The trimmed graph is created in the body of the constructor to ensure
2850   // that the DenseMaps have been initialized already.
2851   InterExplodedGraphMap ForwardMap;
2852   G = OriginalGraph->trim(Nodes, &ForwardMap, &InverseMap);
2853 
2854   // Find the (first) error node in the trimmed graph.  We just need to consult
2855   // the node map which maps from nodes in the original graph to nodes
2856   // in the new graph.
2857   llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes;
2858 
2859   for (unsigned i = 0, count = Nodes.size(); i < count; ++i) {
2860     if (const ExplodedNode *NewNode = ForwardMap.lookup(Nodes[i])) {
2861       ReportNodes.push_back(std::make_pair(NewNode, i));
2862       RemainingNodes.insert(NewNode);
2863     }
2864   }
2865 
2866   assert(!RemainingNodes.empty() && "No error node found in the trimmed graph");
2867 
2868   // Perform a forward BFS to find all the shortest paths.
2869   std::queue<const ExplodedNode *> WS;
2870 
2871   assert(G->num_roots() == 1);
2872   WS.push(*G->roots_begin());
2873   unsigned Priority = 0;
2874 
2875   while (!WS.empty()) {
2876     const ExplodedNode *Node = WS.front();
2877     WS.pop();
2878 
2879     PriorityMapTy::iterator PriorityEntry;
2880     bool IsNew;
2881     std::tie(PriorityEntry, IsNew) =
2882       PriorityMap.insert(std::make_pair(Node, Priority));
2883     ++Priority;
2884 
2885     if (!IsNew) {
2886       assert(PriorityEntry->second <= Priority);
2887       continue;
2888     }
2889 
2890     if (RemainingNodes.erase(Node))
2891       if (RemainingNodes.empty())
2892         break;
2893 
2894     for (ExplodedNode::const_pred_iterator I = Node->succ_begin(),
2895                                            E = Node->succ_end();
2896          I != E; ++I)
2897       WS.push(*I);
2898   }
2899 
2900   // Sort the error paths from longest to shortest.
2901   std::sort(ReportNodes.begin(), ReportNodes.end(),
2902             PriorityCompare<true>(PriorityMap));
2903 }
2904 
popNextReportGraph(ReportGraph & GraphWrapper)2905 bool TrimmedGraph::popNextReportGraph(ReportGraph &GraphWrapper) {
2906   if (ReportNodes.empty())
2907     return false;
2908 
2909   const ExplodedNode *OrigN;
2910   std::tie(OrigN, GraphWrapper.Index) = ReportNodes.pop_back_val();
2911   assert(PriorityMap.find(OrigN) != PriorityMap.end() &&
2912          "error node not accessible from root");
2913 
2914   // Create a new graph with a single path.  This is the graph
2915   // that will be returned to the caller.
2916   auto GNew = llvm::make_unique<ExplodedGraph>();
2917   GraphWrapper.BackMap.clear();
2918 
2919   // Now walk from the error node up the BFS path, always taking the
2920   // predeccessor with the lowest number.
2921   ExplodedNode *Succ = nullptr;
2922   while (true) {
2923     // Create the equivalent node in the new graph with the same state
2924     // and location.
2925     ExplodedNode *NewN = GNew->createUncachedNode(OrigN->getLocation(), OrigN->getState(),
2926                                        OrigN->isSink());
2927 
2928     // Store the mapping to the original node.
2929     InterExplodedGraphMap::const_iterator IMitr = InverseMap.find(OrigN);
2930     assert(IMitr != InverseMap.end() && "No mapping to original node.");
2931     GraphWrapper.BackMap[NewN] = IMitr->second;
2932 
2933     // Link up the new node with the previous node.
2934     if (Succ)
2935       Succ->addPredecessor(NewN, *GNew);
2936     else
2937       GraphWrapper.ErrorNode = NewN;
2938 
2939     Succ = NewN;
2940 
2941     // Are we at the final node?
2942     if (OrigN->pred_empty()) {
2943       GNew->addRoot(NewN);
2944       break;
2945     }
2946 
2947     // Find the next predeccessor node.  We choose the node that is marked
2948     // with the lowest BFS number.
2949     OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(),
2950                           PriorityCompare<false>(PriorityMap));
2951   }
2952 
2953   GraphWrapper.Graph = std::move(GNew);
2954 
2955   return true;
2956 }
2957 
2958 
2959 /// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object
2960 ///  and collapses PathDiagosticPieces that are expanded by macros.
CompactPathDiagnostic(PathPieces & path,const SourceManager & SM)2961 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) {
2962   typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>,
2963                                 SourceLocation> > MacroStackTy;
2964 
2965   typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> >
2966           PiecesTy;
2967 
2968   MacroStackTy MacroStack;
2969   PiecesTy Pieces;
2970 
2971   for (PathPieces::const_iterator I = path.begin(), E = path.end();
2972        I!=E; ++I) {
2973 
2974     PathDiagnosticPiece *piece = I->get();
2975 
2976     // Recursively compact calls.
2977     if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){
2978       CompactPathDiagnostic(call->path, SM);
2979     }
2980 
2981     // Get the location of the PathDiagnosticPiece.
2982     const FullSourceLoc Loc = piece->getLocation().asLocation();
2983 
2984     // Determine the instantiation location, which is the location we group
2985     // related PathDiagnosticPieces.
2986     SourceLocation InstantiationLoc = Loc.isMacroID() ?
2987                                       SM.getExpansionLoc(Loc) :
2988                                       SourceLocation();
2989 
2990     if (Loc.isFileID()) {
2991       MacroStack.clear();
2992       Pieces.push_back(piece);
2993       continue;
2994     }
2995 
2996     assert(Loc.isMacroID());
2997 
2998     // Is the PathDiagnosticPiece within the same macro group?
2999     if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) {
3000       MacroStack.back().first->subPieces.push_back(piece);
3001       continue;
3002     }
3003 
3004     // We aren't in the same group.  Are we descending into a new macro
3005     // or are part of an old one?
3006     IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup;
3007 
3008     SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ?
3009                                           SM.getExpansionLoc(Loc) :
3010                                           SourceLocation();
3011 
3012     // Walk the entire macro stack.
3013     while (!MacroStack.empty()) {
3014       if (InstantiationLoc == MacroStack.back().second) {
3015         MacroGroup = MacroStack.back().first;
3016         break;
3017       }
3018 
3019       if (ParentInstantiationLoc == MacroStack.back().second) {
3020         MacroGroup = MacroStack.back().first;
3021         break;
3022       }
3023 
3024       MacroStack.pop_back();
3025     }
3026 
3027     if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) {
3028       // Create a new macro group and add it to the stack.
3029       PathDiagnosticMacroPiece *NewGroup =
3030         new PathDiagnosticMacroPiece(
3031           PathDiagnosticLocation::createSingleLocation(piece->getLocation()));
3032 
3033       if (MacroGroup)
3034         MacroGroup->subPieces.push_back(NewGroup);
3035       else {
3036         assert(InstantiationLoc.isFileID());
3037         Pieces.push_back(NewGroup);
3038       }
3039 
3040       MacroGroup = NewGroup;
3041       MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc));
3042     }
3043 
3044     // Finally, add the PathDiagnosticPiece to the group.
3045     MacroGroup->subPieces.push_back(piece);
3046   }
3047 
3048   // Now take the pieces and construct a new PathDiagnostic.
3049   path.clear();
3050 
3051   path.insert(path.end(), Pieces.begin(), Pieces.end());
3052 }
3053 
generatePathDiagnostic(PathDiagnostic & PD,PathDiagnosticConsumer & PC,ArrayRef<BugReport * > & bugReports)3054 bool GRBugReporter::generatePathDiagnostic(PathDiagnostic& PD,
3055                                            PathDiagnosticConsumer &PC,
3056                                            ArrayRef<BugReport *> &bugReports) {
3057   assert(!bugReports.empty());
3058 
3059   bool HasValid = false;
3060   bool HasInvalid = false;
3061   SmallVector<const ExplodedNode *, 32> errorNodes;
3062   for (ArrayRef<BugReport*>::iterator I = bugReports.begin(),
3063                                       E = bugReports.end(); I != E; ++I) {
3064     if ((*I)->isValid()) {
3065       HasValid = true;
3066       errorNodes.push_back((*I)->getErrorNode());
3067     } else {
3068       // Keep the errorNodes list in sync with the bugReports list.
3069       HasInvalid = true;
3070       errorNodes.push_back(nullptr);
3071     }
3072   }
3073 
3074   // If all the reports have been marked invalid by a previous path generation,
3075   // we're done.
3076   if (!HasValid)
3077     return false;
3078 
3079   typedef PathDiagnosticConsumer::PathGenerationScheme PathGenerationScheme;
3080   PathGenerationScheme ActiveScheme = PC.getGenerationScheme();
3081 
3082   if (ActiveScheme == PathDiagnosticConsumer::Extensive) {
3083     AnalyzerOptions &options = getAnalyzerOptions();
3084     if (options.getBooleanOption("path-diagnostics-alternate", true)) {
3085       ActiveScheme = PathDiagnosticConsumer::AlternateExtensive;
3086     }
3087   }
3088 
3089   TrimmedGraph TrimG(&getGraph(), errorNodes);
3090   ReportGraph ErrorGraph;
3091 
3092   while (TrimG.popNextReportGraph(ErrorGraph)) {
3093     // Find the BugReport with the original location.
3094     assert(ErrorGraph.Index < bugReports.size());
3095     BugReport *R = bugReports[ErrorGraph.Index];
3096     assert(R && "No original report found for sliced graph.");
3097     assert(R->isValid() && "Report selected by trimmed graph marked invalid.");
3098 
3099     // Start building the path diagnostic...
3100     PathDiagnosticBuilder PDB(*this, R, ErrorGraph.BackMap, &PC);
3101     const ExplodedNode *N = ErrorGraph.ErrorNode;
3102 
3103     // Register additional node visitors.
3104     R->addVisitor(llvm::make_unique<NilReceiverBRVisitor>());
3105     R->addVisitor(llvm::make_unique<ConditionBRVisitor>());
3106     R->addVisitor(llvm::make_unique<LikelyFalsePositiveSuppressionBRVisitor>());
3107 
3108     BugReport::VisitorList visitors;
3109     unsigned origReportConfigToken, finalReportConfigToken;
3110     LocationContextMap LCM;
3111 
3112     // While generating diagnostics, it's possible the visitors will decide
3113     // new symbols and regions are interesting, or add other visitors based on
3114     // the information they find. If they do, we need to regenerate the path
3115     // based on our new report configuration.
3116     do {
3117       // Get a clean copy of all the visitors.
3118       for (BugReport::visitor_iterator I = R->visitor_begin(),
3119                                        E = R->visitor_end(); I != E; ++I)
3120         visitors.push_back((*I)->clone());
3121 
3122       // Clear out the active path from any previous work.
3123       PD.resetPath();
3124       origReportConfigToken = R->getConfigurationChangeToken();
3125 
3126       // Generate the very last diagnostic piece - the piece is visible before
3127       // the trace is expanded.
3128       std::unique_ptr<PathDiagnosticPiece> LastPiece;
3129       for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end();
3130           I != E; ++I) {
3131         if (std::unique_ptr<PathDiagnosticPiece> Piece =
3132                 (*I)->getEndPath(PDB, N, *R)) {
3133           assert (!LastPiece &&
3134               "There can only be one final piece in a diagnostic.");
3135           LastPiece = std::move(Piece);
3136         }
3137       }
3138 
3139       if (ActiveScheme != PathDiagnosticConsumer::None) {
3140         if (!LastPiece)
3141           LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R);
3142         assert(LastPiece);
3143         PD.setEndOfPath(std::move(LastPiece));
3144       }
3145 
3146       // Make sure we get a clean location context map so we don't
3147       // hold onto old mappings.
3148       LCM.clear();
3149 
3150       switch (ActiveScheme) {
3151       case PathDiagnosticConsumer::AlternateExtensive:
3152         GenerateAlternateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors);
3153         break;
3154       case PathDiagnosticConsumer::Extensive:
3155         GenerateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors);
3156         break;
3157       case PathDiagnosticConsumer::Minimal:
3158         GenerateMinimalPathDiagnostic(PD, PDB, N, LCM, visitors);
3159         break;
3160       case PathDiagnosticConsumer::None:
3161         GenerateVisitorsOnlyPathDiagnostic(PD, PDB, N, visitors);
3162         break;
3163       }
3164 
3165       // Clean up the visitors we used.
3166       visitors.clear();
3167 
3168       // Did anything change while generating this path?
3169       finalReportConfigToken = R->getConfigurationChangeToken();
3170     } while (finalReportConfigToken != origReportConfigToken);
3171 
3172     if (!R->isValid())
3173       continue;
3174 
3175     // Finally, prune the diagnostic path of uninteresting stuff.
3176     if (!PD.path.empty()) {
3177       if (R->shouldPrunePath() && getAnalyzerOptions().shouldPrunePaths()) {
3178         bool stillHasNotes = removeUnneededCalls(PD.getMutablePieces(), R, LCM);
3179         assert(stillHasNotes);
3180         (void)stillHasNotes;
3181       }
3182 
3183       // Redirect all call pieces to have valid locations.
3184       adjustCallLocations(PD.getMutablePieces());
3185       removePiecesWithInvalidLocations(PD.getMutablePieces());
3186 
3187       if (ActiveScheme == PathDiagnosticConsumer::AlternateExtensive) {
3188         SourceManager &SM = getSourceManager();
3189 
3190         // Reduce the number of edges from a very conservative set
3191         // to an aesthetically pleasing subset that conveys the
3192         // necessary information.
3193         OptimizedCallsSet OCS;
3194         while (optimizeEdges(PD.getMutablePieces(), SM, OCS, LCM)) {}
3195 
3196         // Drop the very first function-entry edge. It's not really necessary
3197         // for top-level functions.
3198         dropFunctionEntryEdge(PD.getMutablePieces(), LCM, SM);
3199       }
3200 
3201       // Remove messages that are basically the same, and edges that may not
3202       // make sense.
3203       // We have to do this after edge optimization in the Extensive mode.
3204       removeRedundantMsgs(PD.getMutablePieces());
3205       removeEdgesToDefaultInitializers(PD.getMutablePieces());
3206     }
3207 
3208     // We found a report and didn't suppress it.
3209     return true;
3210   }
3211 
3212   // We suppressed all the reports in this equivalence class.
3213   assert(!HasInvalid && "Inconsistent suppression");
3214   (void)HasInvalid;
3215   return false;
3216 }
3217 
Register(BugType * BT)3218 void BugReporter::Register(BugType *BT) {
3219   BugTypes = F.add(BugTypes, BT);
3220 }
3221 
emitReport(std::unique_ptr<BugReport> R)3222 void BugReporter::emitReport(std::unique_ptr<BugReport> R) {
3223   if (const ExplodedNode *E = R->getErrorNode()) {
3224     // An error node must either be a sink or have a tag, otherwise
3225     // it could get reclaimed before the path diagnostic is created.
3226     assert((E->isSink() || E->getLocation().getTag()) &&
3227             "Error node must either be a sink or have a tag");
3228 
3229     const AnalysisDeclContext *DeclCtx =
3230         E->getLocationContext()->getAnalysisDeclContext();
3231     // The source of autosynthesized body can be handcrafted AST or a model
3232     // file. The locations from handcrafted ASTs have no valid source locations
3233     // and have to be discarded. Locations from model files should be preserved
3234     // for processing and reporting.
3235     if (DeclCtx->isBodyAutosynthesized() &&
3236         !DeclCtx->isBodyAutosynthesizedFromModelFile())
3237       return;
3238   }
3239 
3240   bool ValidSourceLoc = R->getLocation(getSourceManager()).isValid();
3241   assert(ValidSourceLoc);
3242   // If we mess up in a release build, we'd still prefer to just drop the bug
3243   // instead of trying to go on.
3244   if (!ValidSourceLoc)
3245     return;
3246 
3247   // Compute the bug report's hash to determine its equivalence class.
3248   llvm::FoldingSetNodeID ID;
3249   R->Profile(ID);
3250 
3251   // Lookup the equivance class.  If there isn't one, create it.
3252   BugType& BT = R->getBugType();
3253   Register(&BT);
3254   void *InsertPos;
3255   BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos);
3256 
3257   if (!EQ) {
3258     EQ = new BugReportEquivClass(std::move(R));
3259     EQClasses.InsertNode(EQ, InsertPos);
3260     EQClassesVector.push_back(EQ);
3261   } else
3262     EQ->AddReport(std::move(R));
3263 }
3264 
3265 
3266 //===----------------------------------------------------------------------===//
3267 // Emitting reports in equivalence classes.
3268 //===----------------------------------------------------------------------===//
3269 
3270 namespace {
3271 struct FRIEC_WLItem {
3272   const ExplodedNode *N;
3273   ExplodedNode::const_succ_iterator I, E;
3274 
FRIEC_WLItem__anone8e473810411::FRIEC_WLItem3275   FRIEC_WLItem(const ExplodedNode *n)
3276   : N(n), I(N->succ_begin()), E(N->succ_end()) {}
3277 };
3278 }
3279 
3280 static BugReport *
FindReportInEquivalenceClass(BugReportEquivClass & EQ,SmallVectorImpl<BugReport * > & bugReports)3281 FindReportInEquivalenceClass(BugReportEquivClass& EQ,
3282                              SmallVectorImpl<BugReport*> &bugReports) {
3283 
3284   BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end();
3285   assert(I != E);
3286   BugType& BT = I->getBugType();
3287 
3288   // If we don't need to suppress any of the nodes because they are
3289   // post-dominated by a sink, simply add all the nodes in the equivalence class
3290   // to 'Nodes'.  Any of the reports will serve as a "representative" report.
3291   if (!BT.isSuppressOnSink()) {
3292     BugReport *R = &*I;
3293     for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) {
3294       const ExplodedNode *N = I->getErrorNode();
3295       if (N) {
3296         R = &*I;
3297         bugReports.push_back(R);
3298       }
3299     }
3300     return R;
3301   }
3302 
3303   // For bug reports that should be suppressed when all paths are post-dominated
3304   // by a sink node, iterate through the reports in the equivalence class
3305   // until we find one that isn't post-dominated (if one exists).  We use a
3306   // DFS traversal of the ExplodedGraph to find a non-sink node.  We could write
3307   // this as a recursive function, but we don't want to risk blowing out the
3308   // stack for very long paths.
3309   BugReport *exampleReport = nullptr;
3310 
3311   for (; I != E; ++I) {
3312     const ExplodedNode *errorNode = I->getErrorNode();
3313 
3314     if (!errorNode)
3315       continue;
3316     if (errorNode->isSink()) {
3317       llvm_unreachable(
3318            "BugType::isSuppressSink() should not be 'true' for sink end nodes");
3319     }
3320     // No successors?  By definition this nodes isn't post-dominated by a sink.
3321     if (errorNode->succ_empty()) {
3322       bugReports.push_back(&*I);
3323       if (!exampleReport)
3324         exampleReport = &*I;
3325       continue;
3326     }
3327 
3328     // At this point we know that 'N' is not a sink and it has at least one
3329     // successor.  Use a DFS worklist to find a non-sink end-of-path node.
3330     typedef FRIEC_WLItem WLItem;
3331     typedef SmallVector<WLItem, 10> DFSWorkList;
3332     llvm::DenseMap<const ExplodedNode *, unsigned> Visited;
3333 
3334     DFSWorkList WL;
3335     WL.push_back(errorNode);
3336     Visited[errorNode] = 1;
3337 
3338     while (!WL.empty()) {
3339       WLItem &WI = WL.back();
3340       assert(!WI.N->succ_empty());
3341 
3342       for (; WI.I != WI.E; ++WI.I) {
3343         const ExplodedNode *Succ = *WI.I;
3344         // End-of-path node?
3345         if (Succ->succ_empty()) {
3346           // If we found an end-of-path node that is not a sink.
3347           if (!Succ->isSink()) {
3348             bugReports.push_back(&*I);
3349             if (!exampleReport)
3350               exampleReport = &*I;
3351             WL.clear();
3352             break;
3353           }
3354           // Found a sink?  Continue on to the next successor.
3355           continue;
3356         }
3357         // Mark the successor as visited.  If it hasn't been explored,
3358         // enqueue it to the DFS worklist.
3359         unsigned &mark = Visited[Succ];
3360         if (!mark) {
3361           mark = 1;
3362           WL.push_back(Succ);
3363           break;
3364         }
3365       }
3366 
3367       // The worklist may have been cleared at this point.  First
3368       // check if it is empty before checking the last item.
3369       if (!WL.empty() && &WL.back() == &WI)
3370         WL.pop_back();
3371     }
3372   }
3373 
3374   // ExampleReport will be NULL if all the nodes in the equivalence class
3375   // were post-dominated by sinks.
3376   return exampleReport;
3377 }
3378 
FlushReport(BugReportEquivClass & EQ)3379 void BugReporter::FlushReport(BugReportEquivClass& EQ) {
3380   SmallVector<BugReport*, 10> bugReports;
3381   BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports);
3382   if (exampleReport) {
3383     for (PathDiagnosticConsumer *PDC : getPathDiagnosticConsumers()) {
3384       FlushReport(exampleReport, *PDC, bugReports);
3385     }
3386   }
3387 }
3388 
FlushReport(BugReport * exampleReport,PathDiagnosticConsumer & PD,ArrayRef<BugReport * > bugReports)3389 void BugReporter::FlushReport(BugReport *exampleReport,
3390                               PathDiagnosticConsumer &PD,
3391                               ArrayRef<BugReport*> bugReports) {
3392 
3393   // FIXME: Make sure we use the 'R' for the path that was actually used.
3394   // Probably doesn't make a difference in practice.
3395   BugType& BT = exampleReport->getBugType();
3396 
3397   std::unique_ptr<PathDiagnostic> D(new PathDiagnostic(
3398       exampleReport->getBugType().getCheckName(),
3399       exampleReport->getDeclWithIssue(), exampleReport->getBugType().getName(),
3400       exampleReport->getDescription(),
3401       exampleReport->getShortDescription(/*Fallback=*/false), BT.getCategory(),
3402       exampleReport->getUniqueingLocation(),
3403       exampleReport->getUniqueingDecl()));
3404 
3405   MaxBugClassSize = std::max(bugReports.size(),
3406                              static_cast<size_t>(MaxBugClassSize));
3407 
3408   // Generate the full path diagnostic, using the generation scheme
3409   // specified by the PathDiagnosticConsumer. Note that we have to generate
3410   // path diagnostics even for consumers which do not support paths, because
3411   // the BugReporterVisitors may mark this bug as a false positive.
3412   if (!bugReports.empty())
3413     if (!generatePathDiagnostic(*D.get(), PD, bugReports))
3414       return;
3415 
3416   MaxValidBugClassSize = std::max(bugReports.size(),
3417                                   static_cast<size_t>(MaxValidBugClassSize));
3418 
3419   // Examine the report and see if the last piece is in a header. Reset the
3420   // report location to the last piece in the main source file.
3421   AnalyzerOptions& Opts = getAnalyzerOptions();
3422   if (Opts.shouldReportIssuesInMainSourceFile() && !Opts.AnalyzeAll)
3423     D->resetDiagnosticLocationToMainFile();
3424 
3425   // If the path is empty, generate a single step path with the location
3426   // of the issue.
3427   if (D->path.empty()) {
3428     PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager());
3429     auto piece = llvm::make_unique<PathDiagnosticEventPiece>(
3430         L, exampleReport->getDescription());
3431     for (SourceRange Range : exampleReport->getRanges())
3432       piece->addRange(Range);
3433     D->setEndOfPath(std::move(piece));
3434   }
3435 
3436   // Get the meta data.
3437   const BugReport::ExtraTextList &Meta = exampleReport->getExtraText();
3438   for (BugReport::ExtraTextList::const_iterator i = Meta.begin(),
3439                                                 e = Meta.end(); i != e; ++i) {
3440     D->addMeta(*i);
3441   }
3442 
3443   PD.HandlePathDiagnostic(std::move(D));
3444 }
3445 
EmitBasicReport(const Decl * DeclWithIssue,const CheckerBase * Checker,StringRef Name,StringRef Category,StringRef Str,PathDiagnosticLocation Loc,ArrayRef<SourceRange> Ranges)3446 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue,
3447                                   const CheckerBase *Checker,
3448                                   StringRef Name, StringRef Category,
3449                                   StringRef Str, PathDiagnosticLocation Loc,
3450                                   ArrayRef<SourceRange> Ranges) {
3451   EmitBasicReport(DeclWithIssue, Checker->getCheckName(), Name, Category, Str,
3452                   Loc, Ranges);
3453 }
EmitBasicReport(const Decl * DeclWithIssue,CheckName CheckName,StringRef name,StringRef category,StringRef str,PathDiagnosticLocation Loc,ArrayRef<SourceRange> Ranges)3454 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue,
3455                                   CheckName CheckName,
3456                                   StringRef name, StringRef category,
3457                                   StringRef str, PathDiagnosticLocation Loc,
3458                                   ArrayRef<SourceRange> Ranges) {
3459 
3460   // 'BT' is owned by BugReporter.
3461   BugType *BT = getBugTypeForName(CheckName, name, category);
3462   auto R = llvm::make_unique<BugReport>(*BT, str, Loc);
3463   R->setDeclWithIssue(DeclWithIssue);
3464   for (ArrayRef<SourceRange>::iterator I = Ranges.begin(), E = Ranges.end();
3465        I != E; ++I)
3466     R->addRange(*I);
3467   emitReport(std::move(R));
3468 }
3469 
getBugTypeForName(CheckName CheckName,StringRef name,StringRef category)3470 BugType *BugReporter::getBugTypeForName(CheckName CheckName, StringRef name,
3471                                         StringRef category) {
3472   SmallString<136> fullDesc;
3473   llvm::raw_svector_ostream(fullDesc) << CheckName.getName() << ":" << name
3474                                       << ":" << category;
3475   BugType *&BT = StrBugTypes[fullDesc];
3476   if (!BT)
3477     BT = new BugType(CheckName, name, category);
3478   return BT;
3479 }
3480 
dump() const3481 LLVM_DUMP_METHOD void PathPieces::dump() const {
3482   unsigned index = 0;
3483   for (PathPieces::const_iterator I = begin(), E = end(); I != E; ++I) {
3484     llvm::errs() << "[" << index++ << "]  ";
3485     (*I)->dump();
3486     llvm::errs() << "\n";
3487   }
3488 }
3489 
dump() const3490 LLVM_DUMP_METHOD void PathDiagnosticCallPiece::dump() const {
3491   llvm::errs() << "CALL\n--------------\n";
3492 
3493   if (const Stmt *SLoc = getLocStmt(getLocation()))
3494     SLoc->dump();
3495   else if (const NamedDecl *ND = dyn_cast<NamedDecl>(getCallee()))
3496     llvm::errs() << *ND << "\n";
3497   else
3498     getLocation().dump();
3499 }
3500 
dump() const3501 LLVM_DUMP_METHOD void PathDiagnosticEventPiece::dump() const {
3502   llvm::errs() << "EVENT\n--------------\n";
3503   llvm::errs() << getString() << "\n";
3504   llvm::errs() << " ---- at ----\n";
3505   getLocation().dump();
3506 }
3507 
dump() const3508 LLVM_DUMP_METHOD void PathDiagnosticControlFlowPiece::dump() const {
3509   llvm::errs() << "CONTROL\n--------------\n";
3510   getStartLocation().dump();
3511   llvm::errs() << " ---- to ----\n";
3512   getEndLocation().dump();
3513 }
3514 
dump() const3515 LLVM_DUMP_METHOD void PathDiagnosticMacroPiece::dump() const {
3516   llvm::errs() << "MACRO\n--------------\n";
3517   // FIXME: Print which macro is being invoked.
3518 }
3519 
dump() const3520 LLVM_DUMP_METHOD void PathDiagnosticLocation::dump() const {
3521   if (!isValid()) {
3522     llvm::errs() << "<INVALID>\n";
3523     return;
3524   }
3525 
3526   switch (K) {
3527   case RangeK:
3528     // FIXME: actually print the range.
3529     llvm::errs() << "<range>\n";
3530     break;
3531   case SingleLocK:
3532     asLocation().dump();
3533     llvm::errs() << "\n";
3534     break;
3535   case StmtK:
3536     if (S)
3537       S->dump();
3538     else
3539       llvm::errs() << "<NULL STMT>\n";
3540     break;
3541   case DeclK:
3542     if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(D))
3543       llvm::errs() << *ND << "\n";
3544     else if (isa<BlockDecl>(D))
3545       // FIXME: Make this nicer.
3546       llvm::errs() << "<block>\n";
3547     else if (D)
3548       llvm::errs() << "<unknown decl>\n";
3549     else
3550       llvm::errs() << "<NULL DECL>\n";
3551     break;
3552   }
3553 }
3554