1 // BugReporter.cpp - Generate PathDiagnostics for Bugs ------------*- C++ -*--//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file defines BugReporter, a utility class for generating
13 //===----------------------------------------------------------------------===//
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/CFGStmtMap.h"
25 #include "clang/Analysis/ProgramPoint.h"
26 #include "clang/Basic/SourceManager.h"
27 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
28 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h"
29 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
30 #include "llvm/ADT/DenseMap.h"
31 #include "llvm/ADT/IntrusiveRefCntPtr.h"
32 #include "llvm/ADT/STLExtras.h"
33 #include "llvm/ADT/SmallString.h"
34 #include "llvm/ADT/Statistic.h"
35 #include "llvm/Support/raw_ostream.h"
39 using namespace clang;
42 #define DEBUG_TYPE "BugReporter"
44 STATISTIC(MaxBugClassSize,
45 "The maximum number of bug reports in the same equivalence class");
46 STATISTIC(MaxValidBugClassSize,
47 "The maximum number of bug reports in the same equivalence class "
48 "where at least one report is valid (not suppressed)");
50 BugReporterVisitor::~BugReporterVisitor() {}
52 void BugReporterContext::anchor() {}
54 //===----------------------------------------------------------------------===//
55 // Helper routines for walking the ExplodedGraph and fetching statements.
56 //===----------------------------------------------------------------------===//
58 static const Stmt *GetPreviousStmt(const ExplodedNode *N) {
59 for (N = N->getFirstPred(); N; N = N->getFirstPred())
60 if (const Stmt *S = PathDiagnosticLocation::getStmt(N))
66 static inline const Stmt*
67 GetCurrentOrPreviousStmt(const ExplodedNode *N) {
68 if (const Stmt *S = PathDiagnosticLocation::getStmt(N))
71 return GetPreviousStmt(N);
74 //===----------------------------------------------------------------------===//
75 // Diagnostic cleanup.
76 //===----------------------------------------------------------------------===//
78 static PathDiagnosticEventPiece *
79 eventsDescribeSameCondition(PathDiagnosticEventPiece *X,
80 PathDiagnosticEventPiece *Y) {
81 // Prefer diagnostics that come from ConditionBRVisitor over
82 // those that came from TrackConstraintBRVisitor,
83 // unless the one from ConditionBRVisitor is
84 // its generic fallback diagnostic.
85 const void *tagPreferred = ConditionBRVisitor::getTag();
86 const void *tagLesser = TrackConstraintBRVisitor::getTag();
88 if (X->getLocation() != Y->getLocation())
91 if (X->getTag() == tagPreferred && Y->getTag() == tagLesser)
92 return ConditionBRVisitor::isPieceMessageGeneric(X) ? Y : X;
94 if (Y->getTag() == tagPreferred && X->getTag() == tagLesser)
95 return ConditionBRVisitor::isPieceMessageGeneric(Y) ? X : Y;
100 /// An optimization pass over PathPieces that removes redundant diagnostics
101 /// generated by both ConditionBRVisitor and TrackConstraintBRVisitor. Both
102 /// BugReporterVisitors use different methods to generate diagnostics, with
103 /// one capable of emitting diagnostics in some cases but not in others. This
104 /// can lead to redundant diagnostic pieces at the same point in a path.
105 static void removeRedundantMsgs(PathPieces &path) {
106 unsigned N = path.size();
109 // NOTE: this loop intentionally is not using an iterator. Instead, we
110 // are streaming the path and modifying it in place. This is done by
111 // grabbing the front, processing it, and if we decide to keep it append
112 // it to the end of the path. The entire path is processed in this way.
113 for (unsigned i = 0; i < N; ++i) {
114 auto piece = std::move(path.front());
117 switch (piece->getKind()) {
118 case PathDiagnosticPiece::Call:
119 removeRedundantMsgs(cast<PathDiagnosticCallPiece>(*piece).path);
121 case PathDiagnosticPiece::Macro:
122 removeRedundantMsgs(cast<PathDiagnosticMacroPiece>(*piece).subPieces);
124 case PathDiagnosticPiece::ControlFlow:
126 case PathDiagnosticPiece::Event: {
130 if (PathDiagnosticEventPiece *nextEvent =
131 dyn_cast<PathDiagnosticEventPiece>(path.front().get())) {
132 PathDiagnosticEventPiece *event =
133 cast<PathDiagnosticEventPiece>(piece.get());
134 // Check to see if we should keep one of the two pieces. If we
135 // come up with a preference, record which piece to keep, and consume
136 // another piece from the path.
137 if (auto *pieceToKeep =
138 eventsDescribeSameCondition(event, nextEvent)) {
139 piece = std::move(pieceToKeep == event ? piece : path.front());
146 case PathDiagnosticPiece::Note:
149 path.push_back(std::move(piece));
153 /// A map from PathDiagnosticPiece to the LocationContext of the inlined
154 /// function call it represents.
155 typedef llvm::DenseMap<const PathPieces *, const LocationContext *>
158 /// Recursively scan through a path and prune out calls and macros pieces
159 /// that aren't needed. Return true if afterwards the path contains
160 /// "interesting stuff" which means it shouldn't be pruned from the parent path.
161 static bool removeUnneededCalls(PathPieces &pieces, BugReport *R,
162 LocationContextMap &LCM) {
163 bool containsSomethingInteresting = false;
164 const unsigned N = pieces.size();
166 for (unsigned i = 0 ; i < N ; ++i) {
167 // Remove the front piece from the path. If it is still something we
168 // want to keep once we are done, we will push it back on the end.
169 auto piece = std::move(pieces.front());
172 switch (piece->getKind()) {
173 case PathDiagnosticPiece::Call: {
174 auto &call = cast<PathDiagnosticCallPiece>(*piece);
175 // Check if the location context is interesting.
176 assert(LCM.count(&call.path));
177 if (R->isInteresting(LCM[&call.path])) {
178 containsSomethingInteresting = true;
182 if (!removeUnneededCalls(call.path, R, LCM))
185 containsSomethingInteresting = true;
188 case PathDiagnosticPiece::Macro: {
189 auto ¯o = cast<PathDiagnosticMacroPiece>(*piece);
190 if (!removeUnneededCalls(macro.subPieces, R, LCM))
192 containsSomethingInteresting = true;
195 case PathDiagnosticPiece::Event: {
196 auto &event = cast<PathDiagnosticEventPiece>(*piece);
198 // We never throw away an event, but we do throw it away wholesale
199 // as part of a path if we throw the entire path away.
200 containsSomethingInteresting |= !event.isPrunable();
203 case PathDiagnosticPiece::ControlFlow:
206 case PathDiagnosticPiece::Note:
210 pieces.push_back(std::move(piece));
213 return containsSomethingInteresting;
216 /// Returns true if the given decl has been implicitly given a body, either by
217 /// the analyzer or by the compiler proper.
218 static bool hasImplicitBody(const Decl *D) {
220 return D->isImplicit() || !D->hasBody();
223 /// Recursively scan through a path and make sure that all call pieces have
226 adjustCallLocations(PathPieces &Pieces,
227 PathDiagnosticLocation *LastCallLocation = nullptr) {
228 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E; ++I) {
229 PathDiagnosticCallPiece *Call = dyn_cast<PathDiagnosticCallPiece>(I->get());
232 assert((*I)->getLocation().asLocation().isValid());
236 if (LastCallLocation) {
237 bool CallerIsImplicit = hasImplicitBody(Call->getCaller());
238 if (CallerIsImplicit || !Call->callEnter.asLocation().isValid())
239 Call->callEnter = *LastCallLocation;
240 if (CallerIsImplicit || !Call->callReturn.asLocation().isValid())
241 Call->callReturn = *LastCallLocation;
244 // Recursively clean out the subclass. Keep this call around if
245 // it contains any informative diagnostics.
246 PathDiagnosticLocation *ThisCallLocation;
247 if (Call->callEnterWithin.asLocation().isValid() &&
248 !hasImplicitBody(Call->getCallee()))
249 ThisCallLocation = &Call->callEnterWithin;
251 ThisCallLocation = &Call->callEnter;
253 assert(ThisCallLocation && "Outermost call has an invalid location");
254 adjustCallLocations(Call->path, ThisCallLocation);
258 /// Remove edges in and out of C++ default initializer expressions. These are
259 /// for fields that have in-class initializers, as opposed to being initialized
260 /// explicitly in a constructor or braced list.
261 static void removeEdgesToDefaultInitializers(PathPieces &Pieces) {
262 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) {
263 if (auto *C = dyn_cast<PathDiagnosticCallPiece>(I->get()))
264 removeEdgesToDefaultInitializers(C->path);
266 if (auto *M = dyn_cast<PathDiagnosticMacroPiece>(I->get()))
267 removeEdgesToDefaultInitializers(M->subPieces);
269 if (auto *CF = dyn_cast<PathDiagnosticControlFlowPiece>(I->get())) {
270 const Stmt *Start = CF->getStartLocation().asStmt();
271 const Stmt *End = CF->getEndLocation().asStmt();
272 if (Start && isa<CXXDefaultInitExpr>(Start)) {
275 } else if (End && isa<CXXDefaultInitExpr>(End)) {
276 PathPieces::iterator Next = std::next(I);
279 dyn_cast<PathDiagnosticControlFlowPiece>(Next->get())) {
280 NextCF->setStartLocation(CF->getStartLocation());
292 /// Remove all pieces with invalid locations as these cannot be serialized.
293 /// We might have pieces with invalid locations as a result of inlining Body
294 /// Farm generated functions.
295 static void removePiecesWithInvalidLocations(PathPieces &Pieces) {
296 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) {
297 if (auto *C = dyn_cast<PathDiagnosticCallPiece>(I->get()))
298 removePiecesWithInvalidLocations(C->path);
300 if (auto *M = dyn_cast<PathDiagnosticMacroPiece>(I->get()))
301 removePiecesWithInvalidLocations(M->subPieces);
303 if (!(*I)->getLocation().isValid() ||
304 !(*I)->getLocation().asLocation().isValid()) {
312 //===----------------------------------------------------------------------===//
313 // PathDiagnosticBuilder and its associated routines and helper objects.
314 //===----------------------------------------------------------------------===//
317 class NodeMapClosure : public BugReport::NodeResolver {
318 InterExplodedGraphMap &M;
320 NodeMapClosure(InterExplodedGraphMap &m) : M(m) {}
322 const ExplodedNode *getOriginalNode(const ExplodedNode *N) override {
327 class PathDiagnosticBuilder : public BugReporterContext {
329 PathDiagnosticConsumer *PDC;
332 const LocationContext *LC;
334 PathDiagnosticBuilder(GRBugReporter &br,
335 BugReport *r, InterExplodedGraphMap &Backmap,
336 PathDiagnosticConsumer *pdc)
337 : BugReporterContext(br),
338 R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext())
341 PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N);
343 PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os,
344 const ExplodedNode *N);
346 BugReport *getBugReport() { return R; }
348 Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); }
350 ParentMap& getParentMap() { return LC->getParentMap(); }
352 const Stmt *getParent(const Stmt *S) {
353 return getParentMap().getParent(S);
356 NodeMapClosure& getNodeResolver() override { return NMC; }
358 PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S);
360 PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const {
361 return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive;
364 bool supportsLogicalOpControlFlow() const {
365 return PDC ? PDC->supportsLogicalOpControlFlow() : true;
368 } // end anonymous namespace
370 PathDiagnosticLocation
371 PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) {
372 if (const Stmt *S = PathDiagnosticLocation::getNextStmt(N))
373 return PathDiagnosticLocation(S, getSourceManager(), LC);
375 return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(),
379 PathDiagnosticLocation
380 PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os,
381 const ExplodedNode *N) {
383 // Slow, but probably doesn't matter.
384 if (os.str().empty())
387 const PathDiagnosticLocation &Loc = ExecutionContinues(N);
390 os << "Execution continues on line "
391 << getSourceManager().getExpansionLineNumber(Loc.asLocation())
394 os << "Execution jumps to the end of the ";
395 const Decl *D = N->getLocationContext()->getDecl();
396 if (isa<ObjCMethodDecl>(D))
398 else if (isa<FunctionDecl>(D))
401 assert(isa<BlockDecl>(D));
402 os << "anonymous block";
410 static const Stmt *getEnclosingParent(const Stmt *S, const ParentMap &PM) {
411 if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S)))
412 return PM.getParentIgnoreParens(S);
414 const Stmt *Parent = PM.getParentIgnoreParens(S);
418 switch (Parent->getStmtClass()) {
419 case Stmt::ForStmtClass:
420 case Stmt::DoStmtClass:
421 case Stmt::WhileStmtClass:
422 case Stmt::ObjCForCollectionStmtClass:
423 case Stmt::CXXForRangeStmtClass:
432 static PathDiagnosticLocation
433 getEnclosingStmtLocation(const Stmt *S, SourceManager &SMgr, const ParentMap &P,
434 const LocationContext *LC, bool allowNestedContexts) {
436 return PathDiagnosticLocation();
438 while (const Stmt *Parent = getEnclosingParent(S, P)) {
439 switch (Parent->getStmtClass()) {
440 case Stmt::BinaryOperatorClass: {
441 const BinaryOperator *B = cast<BinaryOperator>(Parent);
442 if (B->isLogicalOp())
443 return PathDiagnosticLocation(allowNestedContexts ? B : S, SMgr, LC);
446 case Stmt::CompoundStmtClass:
447 case Stmt::StmtExprClass:
448 return PathDiagnosticLocation(S, SMgr, LC);
449 case Stmt::ChooseExprClass:
450 // Similar to '?' if we are referring to condition, just have the edge
451 // point to the entire choose expression.
452 if (allowNestedContexts || cast<ChooseExpr>(Parent)->getCond() == S)
453 return PathDiagnosticLocation(Parent, SMgr, LC);
455 return PathDiagnosticLocation(S, SMgr, LC);
456 case Stmt::BinaryConditionalOperatorClass:
457 case Stmt::ConditionalOperatorClass:
458 // For '?', if we are referring to condition, just have the edge point
459 // to the entire '?' expression.
460 if (allowNestedContexts ||
461 cast<AbstractConditionalOperator>(Parent)->getCond() == S)
462 return PathDiagnosticLocation(Parent, SMgr, LC);
464 return PathDiagnosticLocation(S, SMgr, LC);
465 case Stmt::CXXForRangeStmtClass:
466 if (cast<CXXForRangeStmt>(Parent)->getBody() == S)
467 return PathDiagnosticLocation(S, SMgr, LC);
469 case Stmt::DoStmtClass:
470 return PathDiagnosticLocation(S, SMgr, LC);
471 case Stmt::ForStmtClass:
472 if (cast<ForStmt>(Parent)->getBody() == S)
473 return PathDiagnosticLocation(S, SMgr, LC);
475 case Stmt::IfStmtClass:
476 if (cast<IfStmt>(Parent)->getCond() != S)
477 return PathDiagnosticLocation(S, SMgr, LC);
479 case Stmt::ObjCForCollectionStmtClass:
480 if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S)
481 return PathDiagnosticLocation(S, SMgr, LC);
483 case Stmt::WhileStmtClass:
484 if (cast<WhileStmt>(Parent)->getCond() != S)
485 return PathDiagnosticLocation(S, SMgr, LC);
494 assert(S && "Cannot have null Stmt for PathDiagnosticLocation");
496 return PathDiagnosticLocation(S, SMgr, LC);
499 PathDiagnosticLocation
500 PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) {
501 assert(S && "Null Stmt passed to getEnclosingStmtLocation");
502 return ::getEnclosingStmtLocation(S, getSourceManager(), getParentMap(), LC,
503 /*allowNestedContexts=*/false);
506 //===----------------------------------------------------------------------===//
507 // "Visitors only" path diagnostic generation algorithm.
508 //===----------------------------------------------------------------------===//
509 static bool GenerateVisitorsOnlyPathDiagnostic(
510 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
511 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
512 // All path generation skips the very first node (the error node).
513 // This is because there is special handling for the end-of-path note.
514 N = N->getFirstPred();
518 BugReport *R = PDB.getBugReport();
519 while (const ExplodedNode *Pred = N->getFirstPred()) {
520 for (auto &V : visitors)
521 // Visit all the node pairs, but throw the path pieces away.
522 V->VisitNode(N, Pred, PDB, *R);
530 //===----------------------------------------------------------------------===//
531 // "Minimal" path diagnostic generation algorithm.
532 //===----------------------------------------------------------------------===//
533 typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair;
534 typedef SmallVector<StackDiagPair, 6> StackDiagVector;
536 static void updateStackPiecesWithMessage(PathDiagnosticPiece &P,
537 StackDiagVector &CallStack) {
538 // If the piece contains a special message, add it to all the call
539 // pieces on the active stack.
540 if (PathDiagnosticEventPiece *ep = dyn_cast<PathDiagnosticEventPiece>(&P)) {
542 if (ep->hasCallStackHint())
543 for (StackDiagVector::iterator I = CallStack.begin(),
544 E = CallStack.end(); I != E; ++I) {
545 PathDiagnosticCallPiece *CP = I->first;
546 const ExplodedNode *N = I->second;
547 std::string stackMsg = ep->getCallStackMessage(N);
549 // The last message on the path to final bug is the most important
550 // one. Since we traverse the path backwards, do not add the message
551 // if one has been previously added.
552 if (!CP->hasCallStackMessage())
553 CP->setCallStackMessage(stackMsg);
558 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM);
560 static bool GenerateMinimalPathDiagnostic(
561 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
562 LocationContextMap &LCM,
563 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
565 SourceManager& SMgr = PDB.getSourceManager();
566 const LocationContext *LC = PDB.LC;
567 const ExplodedNode *NextNode = N->pred_empty()
568 ? nullptr : *(N->pred_begin());
570 StackDiagVector CallStack;
574 PDB.LC = N->getLocationContext();
575 NextNode = N->getFirstPred();
577 ProgramPoint P = N->getLocation();
580 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
581 auto C = PathDiagnosticCallPiece::construct(N, *CE, SMgr);
582 // Record the mapping from call piece to LocationContext.
583 LCM[&C->path] = CE->getCalleeContext();
585 PD.getActivePath().push_front(std::move(C));
586 PD.pushActivePath(&P->path);
587 CallStack.push_back(StackDiagPair(P, N));
591 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
592 // Flush all locations, and pop the active path.
593 bool VisitedEntireCall = PD.isWithinCall();
596 // Either we just added a bunch of stuff to the top-level path, or
597 // we have a previous CallExitEnd. If the former, it means that the
598 // path terminated within a function call. We must then take the
599 // current contents of the active path and place it within
600 // a new PathDiagnosticCallPiece.
601 PathDiagnosticCallPiece *C;
602 if (VisitedEntireCall) {
603 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front().get());
605 const Decl *Caller = CE->getLocationContext()->getDecl();
606 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
607 // Record the mapping from call piece to LocationContext.
608 LCM[&C->path] = CE->getCalleeContext();
611 C->setCallee(*CE, SMgr);
612 if (!CallStack.empty()) {
613 assert(CallStack.back().first == C);
614 CallStack.pop_back();
619 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
620 const CFGBlock *Src = BE->getSrc();
621 const CFGBlock *Dst = BE->getDst();
622 const Stmt *T = Src->getTerminator();
627 PathDiagnosticLocation Start =
628 PathDiagnosticLocation::createBegin(T, SMgr,
629 N->getLocationContext());
631 switch (T->getStmtClass()) {
635 case Stmt::GotoStmtClass:
636 case Stmt::IndirectGotoStmtClass: {
637 const Stmt *S = PathDiagnosticLocation::getNextStmt(N);
643 llvm::raw_string_ostream os(sbuf);
644 const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S);
646 os << "Control jumps to line "
647 << End.asLocation().getExpansionLineNumber();
648 PD.getActivePath().push_front(
649 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
654 case Stmt::SwitchStmtClass: {
655 // Figure out what case arm we took.
657 llvm::raw_string_ostream os(sbuf);
659 if (const Stmt *S = Dst->getLabel()) {
660 PathDiagnosticLocation End(S, SMgr, LC);
662 switch (S->getStmtClass()) {
664 os << "No cases match in the switch statement. "
665 "Control jumps to line "
666 << End.asLocation().getExpansionLineNumber();
668 case Stmt::DefaultStmtClass:
669 os << "Control jumps to the 'default' case at line "
670 << End.asLocation().getExpansionLineNumber();
673 case Stmt::CaseStmtClass: {
674 os << "Control jumps to 'case ";
675 const CaseStmt *Case = cast<CaseStmt>(S);
676 const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
678 // Determine if it is an enum.
679 bool GetRawInt = true;
681 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) {
682 // FIXME: Maybe this should be an assertion. Are there cases
683 // were it is not an EnumConstantDecl?
684 const EnumConstantDecl *D =
685 dyn_cast<EnumConstantDecl>(DR->getDecl());
694 os << LHS->EvaluateKnownConstInt(PDB.getASTContext());
697 << End.asLocation().getExpansionLineNumber();
701 PD.getActivePath().push_front(
702 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
706 os << "'Default' branch taken. ";
707 const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N);
708 PD.getActivePath().push_front(
709 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
716 case Stmt::BreakStmtClass:
717 case Stmt::ContinueStmtClass: {
719 llvm::raw_string_ostream os(sbuf);
720 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
721 PD.getActivePath().push_front(
722 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
727 // Determine control-flow for ternary '?'.
728 case Stmt::BinaryConditionalOperatorClass:
729 case Stmt::ConditionalOperatorClass: {
731 llvm::raw_string_ostream os(sbuf);
732 os << "'?' condition is ";
734 if (*(Src->succ_begin()+1) == Dst)
739 PathDiagnosticLocation End = PDB.ExecutionContinues(N);
741 if (const Stmt *S = End.asStmt())
742 End = PDB.getEnclosingStmtLocation(S);
744 PD.getActivePath().push_front(
745 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
750 // Determine control-flow for short-circuited '&&' and '||'.
751 case Stmt::BinaryOperatorClass: {
752 if (!PDB.supportsLogicalOpControlFlow())
755 const BinaryOperator *B = cast<BinaryOperator>(T);
757 llvm::raw_string_ostream os(sbuf);
758 os << "Left side of '";
760 if (B->getOpcode() == BO_LAnd) {
761 os << "&&" << "' is ";
763 if (*(Src->succ_begin()+1) == Dst) {
765 PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
766 PathDiagnosticLocation Start =
767 PathDiagnosticLocation::createOperatorLoc(B, SMgr);
768 PD.getActivePath().push_front(
769 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
774 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
775 PathDiagnosticLocation End = PDB.ExecutionContinues(N);
776 PD.getActivePath().push_front(
777 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
782 assert(B->getOpcode() == BO_LOr);
783 os << "||" << "' is ";
785 if (*(Src->succ_begin()+1) == Dst) {
787 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC);
788 PathDiagnosticLocation End = PDB.ExecutionContinues(N);
789 PD.getActivePath().push_front(
790 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
795 PathDiagnosticLocation End(B->getLHS(), SMgr, LC);
796 PathDiagnosticLocation Start =
797 PathDiagnosticLocation::createOperatorLoc(B, SMgr);
798 PD.getActivePath().push_front(
799 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
807 case Stmt::DoStmtClass: {
808 if (*(Src->succ_begin()) == Dst) {
810 llvm::raw_string_ostream os(sbuf);
812 os << "Loop condition is true. ";
813 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
815 if (const Stmt *S = End.asStmt())
816 End = PDB.getEnclosingStmtLocation(S);
818 PD.getActivePath().push_front(
819 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
823 PathDiagnosticLocation End = PDB.ExecutionContinues(N);
825 if (const Stmt *S = End.asStmt())
826 End = PDB.getEnclosingStmtLocation(S);
828 PD.getActivePath().push_front(
829 std::make_shared<PathDiagnosticControlFlowPiece>(
830 Start, End, "Loop condition is false. Exiting loop"));
836 case Stmt::WhileStmtClass:
837 case Stmt::ForStmtClass: {
838 if (*(Src->succ_begin()+1) == Dst) {
840 llvm::raw_string_ostream os(sbuf);
842 os << "Loop condition is false. ";
843 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N);
844 if (const Stmt *S = End.asStmt())
845 End = PDB.getEnclosingStmtLocation(S);
847 PD.getActivePath().push_front(
848 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
852 PathDiagnosticLocation End = PDB.ExecutionContinues(N);
853 if (const Stmt *S = End.asStmt())
854 End = PDB.getEnclosingStmtLocation(S);
856 PD.getActivePath().push_front(
857 std::make_shared<PathDiagnosticControlFlowPiece>(
858 Start, End, "Loop condition is true. Entering loop body"));
864 case Stmt::IfStmtClass: {
865 PathDiagnosticLocation End = PDB.ExecutionContinues(N);
867 if (const Stmt *S = End.asStmt())
868 End = PDB.getEnclosingStmtLocation(S);
870 if (*(Src->succ_begin()+1) == Dst)
871 PD.getActivePath().push_front(
872 std::make_shared<PathDiagnosticControlFlowPiece>(
873 Start, End, "Taking false branch"));
875 PD.getActivePath().push_front(
876 std::make_shared<PathDiagnosticControlFlowPiece>(
877 Start, End, "Taking true branch"));
886 // Add diagnostic pieces from custom visitors.
887 BugReport *R = PDB.getBugReport();
888 llvm::FoldingSet<PathDiagnosticPiece> DeduplicationSet;
889 for (auto &V : visitors) {
890 if (auto p = V->VisitNode(N, NextNode, PDB, *R)) {
891 if (DeduplicationSet.GetOrInsertNode(p.get()) != p.get())
894 updateStackPiecesWithMessage(*p, CallStack);
895 PD.getActivePath().push_front(std::move(p));
901 if (!PDB.getBugReport()->isValid())
904 // After constructing the full PathDiagnostic, do a pass over it to compact
905 // PathDiagnosticPieces that occur within a macro.
906 CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager());
910 //===----------------------------------------------------------------------===//
911 // "Extensive" PathDiagnostic generation.
912 //===----------------------------------------------------------------------===//
914 static bool IsControlFlowExpr(const Stmt *S) {
915 const Expr *E = dyn_cast<Expr>(S);
920 E = E->IgnoreParenCasts();
922 if (isa<AbstractConditionalOperator>(E))
925 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E))
926 if (B->isLogicalOp())
933 class ContextLocation : public PathDiagnosticLocation {
936 ContextLocation(const PathDiagnosticLocation &L, bool isdead = false)
937 : PathDiagnosticLocation(L), IsDead(isdead) {}
939 void markDead() { IsDead = true; }
940 bool isDead() const { return IsDead; }
943 static PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L,
944 const LocationContext *LC,
945 bool firstCharOnly = false) {
946 if (const Stmt *S = L.asStmt()) {
947 const Stmt *Original = S;
949 // Adjust the location for some expressions that are best referenced
950 // by one of their subexpressions.
951 switch (S->getStmtClass()) {
954 case Stmt::ParenExprClass:
955 case Stmt::GenericSelectionExprClass:
956 S = cast<Expr>(S)->IgnoreParens();
957 firstCharOnly = true;
959 case Stmt::BinaryConditionalOperatorClass:
960 case Stmt::ConditionalOperatorClass:
961 S = cast<AbstractConditionalOperator>(S)->getCond();
962 firstCharOnly = true;
964 case Stmt::ChooseExprClass:
965 S = cast<ChooseExpr>(S)->getCond();
966 firstCharOnly = true;
968 case Stmt::BinaryOperatorClass:
969 S = cast<BinaryOperator>(S)->getLHS();
970 firstCharOnly = true;
978 L = PathDiagnosticLocation(S, L.getManager(), LC);
982 L = PathDiagnosticLocation::createSingleLocation(L);
988 std::vector<ContextLocation> CLocs;
989 typedef std::vector<ContextLocation>::iterator iterator;
991 PathDiagnosticBuilder &PDB;
992 PathDiagnosticLocation PrevLoc;
994 bool IsConsumedExpr(const PathDiagnosticLocation &L);
996 bool containsLocation(const PathDiagnosticLocation &Container,
997 const PathDiagnosticLocation &Containee);
999 PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L);
1003 void popLocation() {
1004 if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) {
1005 // For contexts, we only one the first character as the range.
1006 rawAddEdge(cleanUpLocation(CLocs.back(), PDB.LC, true));
1012 EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb)
1013 : PD(pd), PDB(pdb) {
1015 // If the PathDiagnostic already has pieces, add the enclosing statement
1016 // of the first piece as a context as well.
1017 if (!PD.path.empty()) {
1018 PrevLoc = (*PD.path.begin())->getLocation();
1020 if (const Stmt *S = PrevLoc.asStmt())
1021 addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
1026 while (!CLocs.empty()) popLocation();
1028 // Finally, add an initial edge from the start location of the first
1029 // statement (if it doesn't already exist).
1030 PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin(
1032 PDB.getSourceManager());
1037 void flushLocations() {
1038 while (!CLocs.empty())
1040 PrevLoc = PathDiagnosticLocation();
1043 void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false,
1044 bool IsPostJump = false);
1046 void rawAddEdge(PathDiagnosticLocation NewLoc);
1048 void addContext(const Stmt *S);
1049 void addContext(const PathDiagnosticLocation &L);
1050 void addExtendedContext(const Stmt *S);
1052 } // end anonymous namespace
1055 PathDiagnosticLocation
1056 EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) {
1057 if (const Stmt *S = L.asStmt()) {
1058 if (IsControlFlowExpr(S))
1061 return PDB.getEnclosingStmtLocation(S);
1067 bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container,
1068 const PathDiagnosticLocation &Containee) {
1070 if (Container == Containee)
1073 if (Container.asDecl())
1076 if (const Stmt *S = Containee.asStmt())
1077 if (const Stmt *ContainerS = Container.asStmt()) {
1079 if (S == ContainerS)
1081 S = PDB.getParent(S);
1086 // Less accurate: compare using source ranges.
1087 SourceRange ContainerR = Container.asRange();
1088 SourceRange ContaineeR = Containee.asRange();
1090 SourceManager &SM = PDB.getSourceManager();
1091 SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin());
1092 SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd());
1093 SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin());
1094 SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd());
1096 unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg);
1097 unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd);
1098 unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg);
1099 unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd);
1101 assert(ContainerBegLine <= ContainerEndLine);
1102 assert(ContaineeBegLine <= ContaineeEndLine);
1104 return (ContainerBegLine <= ContaineeBegLine &&
1105 ContainerEndLine >= ContaineeEndLine &&
1106 (ContainerBegLine != ContaineeBegLine ||
1107 SM.getExpansionColumnNumber(ContainerRBeg) <=
1108 SM.getExpansionColumnNumber(ContaineeRBeg)) &&
1109 (ContainerEndLine != ContaineeEndLine ||
1110 SM.getExpansionColumnNumber(ContainerREnd) >=
1111 SM.getExpansionColumnNumber(ContaineeREnd)));
1114 void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) {
1115 if (!PrevLoc.isValid()) {
1120 const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc, PDB.LC);
1121 const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc, PDB.LC);
1123 if (PrevLocClean.asLocation().isInvalid()) {
1128 if (NewLocClean.asLocation() == PrevLocClean.asLocation())
1131 // FIXME: Ignore intra-macro edges for now.
1132 if (NewLocClean.asLocation().getExpansionLoc() ==
1133 PrevLocClean.asLocation().getExpansionLoc())
1136 PD.getActivePath().push_front(
1137 std::make_shared<PathDiagnosticControlFlowPiece>(NewLocClean,
1142 void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd,
1145 if (!alwaysAdd && NewLoc.asLocation().isMacroID())
1148 const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc);
1150 while (!CLocs.empty()) {
1151 ContextLocation &TopContextLoc = CLocs.back();
1153 // Is the top location context the same as the one for the new location?
1154 if (TopContextLoc == CLoc) {
1156 if (IsConsumedExpr(TopContextLoc))
1157 TopContextLoc.markDead();
1163 TopContextLoc.markDead();
1167 if (containsLocation(TopContextLoc, CLoc)) {
1171 if (IsConsumedExpr(CLoc)) {
1172 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/true));
1177 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/IsPostJump));
1181 // Context does not contain the location. Flush it.
1185 // If we reach here, there is no enclosing context. Just add the edge.
1189 bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) {
1190 if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt()))
1191 return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X);
1196 void EdgeBuilder::addExtendedContext(const Stmt *S) {
1200 const Stmt *Parent = PDB.getParent(S);
1202 if (isa<CompoundStmt>(Parent))
1203 Parent = PDB.getParent(Parent);
1209 switch (Parent->getStmtClass()) {
1210 case Stmt::DoStmtClass:
1211 case Stmt::ObjCAtSynchronizedStmtClass:
1221 void EdgeBuilder::addContext(const Stmt *S) {
1225 PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC);
1229 void EdgeBuilder::addContext(const PathDiagnosticLocation &L) {
1230 while (!CLocs.empty()) {
1231 const PathDiagnosticLocation &TopContextLoc = CLocs.back();
1233 // Is the top location context the same as the one for the new location?
1234 if (TopContextLoc == L)
1237 if (containsLocation(TopContextLoc, L)) {
1242 // Context does not contain the location. Flush it.
1249 // Cone-of-influence: support the reverse propagation of "interesting" symbols
1250 // and values by tracing interesting calculations backwards through evaluated
1251 // expressions along a path. This is probably overly complicated, but the idea
1252 // is that if an expression computed an "interesting" value, the child
1253 // expressions are are also likely to be "interesting" as well (which then
1254 // propagates to the values they in turn compute). This reverse propagation
1255 // is needed to track interesting correlations across function call boundaries,
1256 // where formal arguments bind to actual arguments, etc. This is also needed
1257 // because the constraint solver sometimes simplifies certain symbolic values
1258 // into constants when appropriate, and this complicates reasoning about
1259 // interesting values.
1260 typedef llvm::DenseSet<const Expr *> InterestingExprs;
1262 static void reversePropagateIntererstingSymbols(BugReport &R,
1263 InterestingExprs &IE,
1264 const ProgramState *State,
1266 const LocationContext *LCtx) {
1267 SVal V = State->getSVal(Ex, LCtx);
1268 if (!(R.isInteresting(V) || IE.count(Ex)))
1271 switch (Ex->getStmtClass()) {
1273 if (!isa<CastExpr>(Ex))
1276 case Stmt::BinaryOperatorClass:
1277 case Stmt::UnaryOperatorClass: {
1278 for (const Stmt *SubStmt : Ex->children()) {
1279 if (const Expr *child = dyn_cast_or_null<Expr>(SubStmt)) {
1281 SVal ChildV = State->getSVal(child, LCtx);
1282 R.markInteresting(ChildV);
1289 R.markInteresting(V);
1292 static void reversePropagateInterestingSymbols(BugReport &R,
1293 InterestingExprs &IE,
1294 const ProgramState *State,
1295 const LocationContext *CalleeCtx,
1296 const LocationContext *CallerCtx)
1298 // FIXME: Handle non-CallExpr-based CallEvents.
1299 const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame();
1300 const Stmt *CallSite = Callee->getCallSite();
1301 if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) {
1302 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) {
1303 FunctionDecl::param_const_iterator PI = FD->param_begin(),
1304 PE = FD->param_end();
1305 CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end();
1306 for (; AI != AE && PI != PE; ++AI, ++PI) {
1307 if (const Expr *ArgE = *AI) {
1308 if (const ParmVarDecl *PD = *PI) {
1309 Loc LV = State->getLValue(PD, CalleeCtx);
1310 if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV)))
1319 //===----------------------------------------------------------------------===//
1320 // Functions for determining if a loop was executed 0 times.
1321 //===----------------------------------------------------------------------===//
1323 static bool isLoop(const Stmt *Term) {
1324 switch (Term->getStmtClass()) {
1325 case Stmt::ForStmtClass:
1326 case Stmt::WhileStmtClass:
1327 case Stmt::ObjCForCollectionStmtClass:
1328 case Stmt::CXXForRangeStmtClass:
1331 // Note that we intentionally do not include do..while here.
1336 static bool isJumpToFalseBranch(const BlockEdge *BE) {
1337 const CFGBlock *Src = BE->getSrc();
1338 assert(Src->succ_size() == 2);
1339 return (*(Src->succ_begin()+1) == BE->getDst());
1342 /// Return true if the terminator is a loop and the destination is the
1344 static bool isLoopJumpPastBody(const Stmt *Term, const BlockEdge *BE) {
1348 // Did we take the false branch?
1349 return isJumpToFalseBranch(BE);
1352 static bool isContainedByStmt(ParentMap &PM, const Stmt *S, const Stmt *SubS) {
1356 SubS = PM.getParent(SubS);
1361 static const Stmt *getStmtBeforeCond(ParentMap &PM, const Stmt *Term,
1362 const ExplodedNode *N) {
1364 Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>();
1366 const Stmt *S = SP->getStmt();
1367 if (!isContainedByStmt(PM, Term, S))
1370 N = N->getFirstPred();
1375 static bool isInLoopBody(ParentMap &PM, const Stmt *S, const Stmt *Term) {
1376 const Stmt *LoopBody = nullptr;
1377 switch (Term->getStmtClass()) {
1378 case Stmt::CXXForRangeStmtClass: {
1379 const CXXForRangeStmt *FR = cast<CXXForRangeStmt>(Term);
1380 if (isContainedByStmt(PM, FR->getInc(), S))
1382 if (isContainedByStmt(PM, FR->getLoopVarStmt(), S))
1384 LoopBody = FR->getBody();
1387 case Stmt::ForStmtClass: {
1388 const ForStmt *FS = cast<ForStmt>(Term);
1389 if (isContainedByStmt(PM, FS->getInc(), S))
1391 LoopBody = FS->getBody();
1394 case Stmt::ObjCForCollectionStmtClass: {
1395 const ObjCForCollectionStmt *FC = cast<ObjCForCollectionStmt>(Term);
1396 LoopBody = FC->getBody();
1399 case Stmt::WhileStmtClass:
1400 LoopBody = cast<WhileStmt>(Term)->getBody();
1405 return isContainedByStmt(PM, LoopBody, S);
1408 //===----------------------------------------------------------------------===//
1409 // Top-level logic for generating extensive path diagnostics.
1410 //===----------------------------------------------------------------------===//
1412 static bool GenerateExtensivePathDiagnostic(
1413 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
1414 LocationContextMap &LCM,
1415 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
1416 EdgeBuilder EB(PD, PDB);
1417 const SourceManager& SM = PDB.getSourceManager();
1418 StackDiagVector CallStack;
1419 InterestingExprs IE;
1421 const ExplodedNode *NextNode = N->pred_empty() ? nullptr : *(N->pred_begin());
1424 NextNode = N->getFirstPred();
1425 ProgramPoint P = N->getLocation();
1428 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) {
1429 if (const Expr *Ex = PS->getStmtAs<Expr>())
1430 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1431 N->getState().get(), Ex,
1432 N->getLocationContext());
1435 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
1436 const Stmt *S = CE->getCalleeContext()->getCallSite();
1437 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) {
1438 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1439 N->getState().get(), Ex,
1440 N->getLocationContext());
1443 auto C = PathDiagnosticCallPiece::construct(N, *CE, SM);
1444 LCM[&C->path] = CE->getCalleeContext();
1446 EB.addEdge(C->callReturn, /*AlwaysAdd=*/true, /*IsPostJump=*/true);
1447 EB.flushLocations();
1450 PD.getActivePath().push_front(std::move(C));
1451 PD.pushActivePath(&P->path);
1452 CallStack.push_back(StackDiagPair(P, N));
1456 // Pop the call hierarchy if we are done walking the contents
1457 // of a function call.
1458 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
1459 // Add an edge to the start of the function.
1460 const Decl *D = CE->getCalleeContext()->getDecl();
1461 PathDiagnosticLocation pos =
1462 PathDiagnosticLocation::createBegin(D, SM);
1465 // Flush all locations, and pop the active path.
1466 bool VisitedEntireCall = PD.isWithinCall();
1467 EB.flushLocations();
1469 PDB.LC = N->getLocationContext();
1471 // Either we just added a bunch of stuff to the top-level path, or
1472 // we have a previous CallExitEnd. If the former, it means that the
1473 // path terminated within a function call. We must then take the
1474 // current contents of the active path and place it within
1475 // a new PathDiagnosticCallPiece.
1476 PathDiagnosticCallPiece *C;
1477 if (VisitedEntireCall) {
1478 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front().get());
1480 const Decl *Caller = CE->getLocationContext()->getDecl();
1481 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
1482 LCM[&C->path] = CE->getCalleeContext();
1485 C->setCallee(*CE, SM);
1486 EB.addContext(C->getLocation());
1488 if (!CallStack.empty()) {
1489 assert(CallStack.back().first == C);
1490 CallStack.pop_back();
1495 // Note that is important that we update the LocationContext
1496 // after looking at CallExits. CallExit basically adds an
1497 // edge in the *caller*, so we don't want to update the LocationContext
1499 PDB.LC = N->getLocationContext();
1502 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
1503 // Does this represent entering a call? If so, look at propagating
1504 // interesting symbols across call boundaries.
1506 const LocationContext *CallerCtx = NextNode->getLocationContext();
1507 const LocationContext *CalleeCtx = PDB.LC;
1508 if (CallerCtx != CalleeCtx) {
1509 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE,
1510 N->getState().get(),
1511 CalleeCtx, CallerCtx);
1515 // Are we jumping to the head of a loop? Add a special diagnostic.
1516 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) {
1517 PathDiagnosticLocation L(Loop, SM, PDB.LC);
1518 const CompoundStmt *CS = nullptr;
1520 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
1521 CS = dyn_cast<CompoundStmt>(FS->getBody());
1522 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
1523 CS = dyn_cast<CompoundStmt>(WS->getBody());
1525 auto p = std::make_shared<PathDiagnosticEventPiece>(
1526 L, "Looping back to the head of the loop");
1527 p->setPrunable(true);
1529 EB.addEdge(p->getLocation(), true);
1530 PD.getActivePath().push_front(std::move(p));
1533 PathDiagnosticLocation BL =
1534 PathDiagnosticLocation::createEndBrace(CS, SM);
1539 const CFGBlock *BSrc = BE->getSrc();
1540 ParentMap &PM = PDB.getParentMap();
1542 if (const Stmt *Term = BSrc->getTerminator()) {
1543 // Are we jumping past the loop body without ever executing the
1544 // loop (because the condition was false)?
1545 if (isLoopJumpPastBody(Term, &*BE) &&
1547 getStmtBeforeCond(PM,
1548 BSrc->getTerminatorCondition(),
1551 PathDiagnosticLocation L(Term, SM, PDB.LC);
1552 auto PE = std::make_shared<PathDiagnosticEventPiece>(
1553 L, "Loop body executed 0 times");
1554 PE->setPrunable(true);
1556 EB.addEdge(PE->getLocation(), true);
1557 PD.getActivePath().push_front(std::move(PE));
1560 // In any case, add the terminator as the current statement
1561 // context for control edges.
1562 EB.addContext(Term);
1568 if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) {
1569 Optional<CFGElement> First = BE->getFirstElement();
1570 if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) {
1571 const Stmt *stmt = S->getStmt();
1572 if (IsControlFlowExpr(stmt)) {
1573 // Add the proper context for '&&', '||', and '?'.
1574 EB.addContext(stmt);
1577 EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt());
1589 // Add pieces from custom visitors.
1590 BugReport *R = PDB.getBugReport();
1591 llvm::FoldingSet<PathDiagnosticPiece> DeduplicationSet;
1592 for (auto &V : visitors) {
1593 if (auto p = V->VisitNode(N, NextNode, PDB, *R)) {
1594 if (DeduplicationSet.GetOrInsertNode(p.get()) != p.get())
1597 const PathDiagnosticLocation &Loc = p->getLocation();
1598 EB.addEdge(Loc, true);
1599 updateStackPiecesWithMessage(*p, CallStack);
1600 PD.getActivePath().push_front(std::move(p));
1602 if (const Stmt *S = Loc.asStmt())
1603 EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt());
1608 return PDB.getBugReport()->isValid();
1611 /// \brief Adds a sanitized control-flow diagnostic edge to a path.
1612 static void addEdgeToPath(PathPieces &path,
1613 PathDiagnosticLocation &PrevLoc,
1614 PathDiagnosticLocation NewLoc,
1615 const LocationContext *LC) {
1616 if (!NewLoc.isValid())
1619 SourceLocation NewLocL = NewLoc.asLocation();
1620 if (NewLocL.isInvalid())
1623 if (!PrevLoc.isValid() || !PrevLoc.asLocation().isValid()) {
1628 // Ignore self-edges, which occur when there are multiple nodes at the same
1630 if (NewLoc.asStmt() && NewLoc.asStmt() == PrevLoc.asStmt())
1634 std::make_shared<PathDiagnosticControlFlowPiece>(NewLoc, PrevLoc));
1638 /// A customized wrapper for CFGBlock::getTerminatorCondition()
1639 /// which returns the element for ObjCForCollectionStmts.
1640 static const Stmt *getTerminatorCondition(const CFGBlock *B) {
1641 const Stmt *S = B->getTerminatorCondition();
1642 if (const ObjCForCollectionStmt *FS =
1643 dyn_cast_or_null<ObjCForCollectionStmt>(S))
1644 return FS->getElement();
1648 static const char StrEnteringLoop[] = "Entering loop body";
1649 static const char StrLoopBodyZero[] = "Loop body executed 0 times";
1650 static const char StrLoopRangeEmpty[] =
1651 "Loop body skipped when range is empty";
1652 static const char StrLoopCollectionEmpty[] =
1653 "Loop body skipped when collection is empty";
1655 static bool GenerateAlternateExtensivePathDiagnostic(
1656 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N,
1657 LocationContextMap &LCM,
1658 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) {
1660 BugReport *report = PDB.getBugReport();
1661 const SourceManager& SM = PDB.getSourceManager();
1662 StackDiagVector CallStack;
1663 InterestingExprs IE;
1665 PathDiagnosticLocation PrevLoc = PD.getLocation();
1667 const ExplodedNode *NextNode = N->getFirstPred();
1670 NextNode = N->getFirstPred();
1671 ProgramPoint P = N->getLocation();
1674 // Have we encountered an entrance to a call? It may be
1675 // the case that we have not encountered a matching
1676 // call exit before this point. This means that the path
1677 // terminated within the call itself.
1678 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) {
1679 // Add an edge to the start of the function.
1680 const StackFrameContext *CalleeLC = CE->getCalleeContext();
1681 const Decl *D = CalleeLC->getDecl();
1682 // Add the edge only when the callee has body. We jump to the beginning
1683 // of the *declaration*, however we expect it to be followed by the
1684 // body. This isn't the case for autosynthesized property accessors in
1685 // Objective-C. No need for a similar extra check for CallExit points
1686 // because the exit edge comes from a statement (i.e. return),
1687 // not from declaration.
1689 addEdgeToPath(PD.getActivePath(), PrevLoc,
1690 PathDiagnosticLocation::createBegin(D, SM), CalleeLC);
1692 // Did we visit an entire call?
1693 bool VisitedEntireCall = PD.isWithinCall();
1696 PathDiagnosticCallPiece *C;
1697 if (VisitedEntireCall) {
1698 PathDiagnosticPiece *P = PD.getActivePath().front().get();
1699 C = cast<PathDiagnosticCallPiece>(P);
1701 const Decl *Caller = CE->getLocationContext()->getDecl();
1702 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller);
1704 // Since we just transferred the path over to the call piece,
1705 // reset the mapping from active to location context.
1706 assert(PD.getActivePath().size() == 1 &&
1707 PD.getActivePath().front().get() == C);
1708 LCM[&PD.getActivePath()] = nullptr;
1710 // Record the location context mapping for the path within
1712 assert(LCM[&C->path] == nullptr ||
1713 LCM[&C->path] == CE->getCalleeContext());
1714 LCM[&C->path] = CE->getCalleeContext();
1716 // If this is the first item in the active path, record
1717 // the new mapping from active path to location context.
1718 const LocationContext *&NewLC = LCM[&PD.getActivePath()];
1720 NewLC = N->getLocationContext();
1724 C->setCallee(*CE, SM);
1726 // Update the previous location in the active path.
1727 PrevLoc = C->getLocation();
1729 if (!CallStack.empty()) {
1730 assert(CallStack.back().first == C);
1731 CallStack.pop_back();
1736 // Query the location context here and the previous location
1737 // as processing CallEnter may change the active path.
1738 PDB.LC = N->getLocationContext();
1740 // Record the mapping from the active path to the location
1742 assert(!LCM[&PD.getActivePath()] ||
1743 LCM[&PD.getActivePath()] == PDB.LC);
1744 LCM[&PD.getActivePath()] = PDB.LC;
1746 // Have we encountered an exit from a function call?
1747 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
1748 const Stmt *S = CE->getCalleeContext()->getCallSite();
1749 // Propagate the interesting symbols accordingly.
1750 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) {
1751 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1752 N->getState().get(), Ex,
1753 N->getLocationContext());
1756 // We are descending into a call (backwards). Construct
1757 // a new call piece to contain the path pieces for that call.
1758 auto C = PathDiagnosticCallPiece::construct(N, *CE, SM);
1760 // Record the location context for this call piece.
1761 LCM[&C->path] = CE->getCalleeContext();
1763 // Add the edge to the return site.
1764 addEdgeToPath(PD.getActivePath(), PrevLoc, C->callReturn, PDB.LC);
1766 PD.getActivePath().push_front(std::move(C));
1767 PrevLoc.invalidate();
1769 // Make the contents of the call the active path for now.
1770 PD.pushActivePath(&P->path);
1771 CallStack.push_back(StackDiagPair(P, N));
1775 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) {
1776 // For expressions, make sure we propagate the
1777 // interesting symbols correctly.
1778 if (const Expr *Ex = PS->getStmtAs<Expr>())
1779 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE,
1780 N->getState().get(), Ex,
1781 N->getLocationContext());
1783 // Add an edge. If this is an ObjCForCollectionStmt do
1784 // not add an edge here as it appears in the CFG both
1785 // as a terminator and as a terminator condition.
1786 if (!isa<ObjCForCollectionStmt>(PS->getStmt())) {
1787 PathDiagnosticLocation L =
1788 PathDiagnosticLocation(PS->getStmt(), SM, PDB.LC);
1789 addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC);
1795 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) {
1796 // Does this represent entering a call? If so, look at propagating
1797 // interesting symbols across call boundaries.
1799 const LocationContext *CallerCtx = NextNode->getLocationContext();
1800 const LocationContext *CalleeCtx = PDB.LC;
1801 if (CallerCtx != CalleeCtx) {
1802 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE,
1803 N->getState().get(),
1804 CalleeCtx, CallerCtx);
1808 // Are we jumping to the head of a loop? Add a special diagnostic.
1809 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) {
1810 PathDiagnosticLocation L(Loop, SM, PDB.LC);
1811 const Stmt *Body = nullptr;
1813 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop))
1814 Body = FS->getBody();
1815 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop))
1816 Body = WS->getBody();
1817 else if (const ObjCForCollectionStmt *OFS =
1818 dyn_cast<ObjCForCollectionStmt>(Loop)) {
1819 Body = OFS->getBody();
1820 } else if (const CXXForRangeStmt *FRS =
1821 dyn_cast<CXXForRangeStmt>(Loop)) {
1822 Body = FRS->getBody();
1824 // do-while statements are explicitly excluded here
1826 auto p = std::make_shared<PathDiagnosticEventPiece>(
1827 L, "Looping back to the head "
1829 p->setPrunable(true);
1831 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC);
1832 PD.getActivePath().push_front(std::move(p));
1834 if (const CompoundStmt *CS = dyn_cast_or_null<CompoundStmt>(Body)) {
1835 addEdgeToPath(PD.getActivePath(), PrevLoc,
1836 PathDiagnosticLocation::createEndBrace(CS, SM),
1841 const CFGBlock *BSrc = BE->getSrc();
1842 ParentMap &PM = PDB.getParentMap();
1844 if (const Stmt *Term = BSrc->getTerminator()) {
1845 // Are we jumping past the loop body without ever executing the
1846 // loop (because the condition was false)?
1848 const Stmt *TermCond = getTerminatorCondition(BSrc);
1850 isInLoopBody(PM, getStmtBeforeCond(PM, TermCond, N), Term);
1852 const char *str = nullptr;
1854 if (isJumpToFalseBranch(&*BE)) {
1855 if (!IsInLoopBody) {
1856 if (isa<ObjCForCollectionStmt>(Term)) {
1857 str = StrLoopCollectionEmpty;
1858 } else if (isa<CXXForRangeStmt>(Term)) {
1859 str = StrLoopRangeEmpty;
1861 str = StrLoopBodyZero;
1865 str = StrEnteringLoop;
1869 PathDiagnosticLocation L(TermCond ? TermCond : Term, SM, PDB.LC);
1870 auto PE = std::make_shared<PathDiagnosticEventPiece>(L, str);
1871 PE->setPrunable(true);
1872 addEdgeToPath(PD.getActivePath(), PrevLoc,
1873 PE->getLocation(), PDB.LC);
1874 PD.getActivePath().push_front(std::move(PE));
1876 } else if (isa<BreakStmt>(Term) || isa<ContinueStmt>(Term) ||
1877 isa<GotoStmt>(Term)) {
1878 PathDiagnosticLocation L(Term, SM, PDB.LC);
1879 addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC);
1889 // Add pieces from custom visitors.
1890 llvm::FoldingSet<PathDiagnosticPiece> DeduplicationSet;
1891 for (auto &V : visitors) {
1892 if (auto p = V->VisitNode(N, NextNode, PDB, *report)) {
1893 if (DeduplicationSet.GetOrInsertNode(p.get()) != p.get())
1896 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC);
1897 updateStackPiecesWithMessage(*p, CallStack);
1898 PD.getActivePath().push_front(std::move(p));
1903 // Add an edge to the start of the function.
1904 // We'll prune it out later, but it helps make diagnostics more uniform.
1905 const StackFrameContext *CalleeLC = PDB.LC->getCurrentStackFrame();
1906 const Decl *D = CalleeLC->getDecl();
1907 addEdgeToPath(PD.getActivePath(), PrevLoc,
1908 PathDiagnosticLocation::createBegin(D, SM),
1911 return report->isValid();
1914 static const Stmt *getLocStmt(PathDiagnosticLocation L) {
1920 static const Stmt *getStmtParent(const Stmt *S, const ParentMap &PM) {
1925 S = PM.getParentIgnoreParens(S);
1930 if (isa<ExprWithCleanups>(S) ||
1931 isa<CXXBindTemporaryExpr>(S) ||
1932 isa<SubstNonTypeTemplateParmExpr>(S))
1941 static bool isConditionForTerminator(const Stmt *S, const Stmt *Cond) {
1942 switch (S->getStmtClass()) {
1943 case Stmt::BinaryOperatorClass: {
1944 const BinaryOperator *BO = cast<BinaryOperator>(S);
1945 if (!BO->isLogicalOp())
1947 return BO->getLHS() == Cond || BO->getRHS() == Cond;
1949 case Stmt::IfStmtClass:
1950 return cast<IfStmt>(S)->getCond() == Cond;
1951 case Stmt::ForStmtClass:
1952 return cast<ForStmt>(S)->getCond() == Cond;
1953 case Stmt::WhileStmtClass:
1954 return cast<WhileStmt>(S)->getCond() == Cond;
1955 case Stmt::DoStmtClass:
1956 return cast<DoStmt>(S)->getCond() == Cond;
1957 case Stmt::ChooseExprClass:
1958 return cast<ChooseExpr>(S)->getCond() == Cond;
1959 case Stmt::IndirectGotoStmtClass:
1960 return cast<IndirectGotoStmt>(S)->getTarget() == Cond;
1961 case Stmt::SwitchStmtClass:
1962 return cast<SwitchStmt>(S)->getCond() == Cond;
1963 case Stmt::BinaryConditionalOperatorClass:
1964 return cast<BinaryConditionalOperator>(S)->getCond() == Cond;
1965 case Stmt::ConditionalOperatorClass: {
1966 const ConditionalOperator *CO = cast<ConditionalOperator>(S);
1967 return CO->getCond() == Cond ||
1968 CO->getLHS() == Cond ||
1969 CO->getRHS() == Cond;
1971 case Stmt::ObjCForCollectionStmtClass:
1972 return cast<ObjCForCollectionStmt>(S)->getElement() == Cond;
1973 case Stmt::CXXForRangeStmtClass: {
1974 const CXXForRangeStmt *FRS = cast<CXXForRangeStmt>(S);
1975 return FRS->getCond() == Cond || FRS->getRangeInit() == Cond;
1982 static bool isIncrementOrInitInForLoop(const Stmt *S, const Stmt *FL) {
1983 if (const ForStmt *FS = dyn_cast<ForStmt>(FL))
1984 return FS->getInc() == S || FS->getInit() == S;
1985 if (const CXXForRangeStmt *FRS = dyn_cast<CXXForRangeStmt>(FL))
1986 return FRS->getInc() == S || FRS->getRangeStmt() == S ||
1987 FRS->getLoopVarStmt() || FRS->getRangeInit() == S;
1991 typedef llvm::DenseSet<const PathDiagnosticCallPiece *>
1994 /// Adds synthetic edges from top-level statements to their subexpressions.
1996 /// This avoids a "swoosh" effect, where an edge from a top-level statement A
1997 /// points to a sub-expression B.1 that's not at the start of B. In these cases,
1998 /// we'd like to see an edge from A to B, then another one from B to B.1.
1999 static void addContextEdges(PathPieces &pieces, SourceManager &SM,
2000 const ParentMap &PM, const LocationContext *LCtx) {
2001 PathPieces::iterator Prev = pieces.end();
2002 for (PathPieces::iterator I = pieces.begin(), E = Prev; I != E;
2004 PathDiagnosticControlFlowPiece *Piece =
2005 dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
2010 PathDiagnosticLocation SrcLoc = Piece->getStartLocation();
2011 SmallVector<PathDiagnosticLocation, 4> SrcContexts;
2013 PathDiagnosticLocation NextSrcContext = SrcLoc;
2014 const Stmt *InnerStmt = nullptr;
2015 while (NextSrcContext.isValid() && NextSrcContext.asStmt() != InnerStmt) {
2016 SrcContexts.push_back(NextSrcContext);
2017 InnerStmt = NextSrcContext.asStmt();
2018 NextSrcContext = getEnclosingStmtLocation(InnerStmt, SM, PM, LCtx,
2019 /*allowNested=*/true);
2022 // Repeatedly split the edge as necessary.
2023 // This is important for nested logical expressions (||, &&, ?:) where we
2024 // want to show all the levels of context.
2026 const Stmt *Dst = getLocStmt(Piece->getEndLocation());
2028 // We are looking at an edge. Is the destination within a larger
2030 PathDiagnosticLocation DstContext =
2031 getEnclosingStmtLocation(Dst, SM, PM, LCtx, /*allowNested=*/true);
2032 if (!DstContext.isValid() || DstContext.asStmt() == Dst)
2035 // If the source is in the same context, we're already good.
2036 if (std::find(SrcContexts.begin(), SrcContexts.end(), DstContext) !=
2040 // Update the subexpression node to point to the context edge.
2041 Piece->setStartLocation(DstContext);
2043 // Try to extend the previous edge if it's at the same level as the source
2046 auto *PrevPiece = dyn_cast<PathDiagnosticControlFlowPiece>(Prev->get());
2049 if (const Stmt *PrevSrc = getLocStmt(PrevPiece->getStartLocation())) {
2050 const Stmt *PrevSrcParent = getStmtParent(PrevSrc, PM);
2051 if (PrevSrcParent == getStmtParent(getLocStmt(DstContext), PM)) {
2052 PrevPiece->setEndLocation(DstContext);
2059 // Otherwise, split the current edge into a context edge and a
2060 // subexpression edge. Note that the context statement may itself have
2063 std::make_shared<PathDiagnosticControlFlowPiece>(SrcLoc, DstContext);
2065 I = pieces.insert(I, std::move(P));
2070 /// \brief Move edges from a branch condition to a branch target
2071 /// when the condition is simple.
2073 /// This restructures some of the work of addContextEdges. That function
2074 /// creates edges this may destroy, but they work together to create a more
2075 /// aesthetically set of edges around branches. After the call to
2076 /// addContextEdges, we may have (1) an edge to the branch, (2) an edge from
2077 /// the branch to the branch condition, and (3) an edge from the branch
2078 /// condition to the branch target. We keep (1), but may wish to remove (2)
2079 /// and move the source of (3) to the branch if the branch condition is simple.
2081 static void simplifySimpleBranches(PathPieces &pieces) {
2082 for (PathPieces::iterator I = pieces.begin(), E = pieces.end(); I != E; ++I) {
2084 auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
2089 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation());
2090 const Stmt *s1End = getLocStmt(PieceI->getEndLocation());
2092 if (!s1Start || !s1End)
2095 PathPieces::iterator NextI = I; ++NextI;
2099 PathDiagnosticControlFlowPiece *PieceNextI = nullptr;
2105 auto *EV = dyn_cast<PathDiagnosticEventPiece>(NextI->get());
2107 StringRef S = EV->getString();
2108 if (S == StrEnteringLoop || S == StrLoopBodyZero ||
2109 S == StrLoopCollectionEmpty || S == StrLoopRangeEmpty) {
2116 PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
2123 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation());
2124 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation());
2126 if (!s2Start || !s2End || s1End != s2Start)
2129 // We only perform this transformation for specific branch kinds.
2130 // We don't want to do this for do..while, for example.
2131 if (!(isa<ForStmt>(s1Start) || isa<WhileStmt>(s1Start) ||
2132 isa<IfStmt>(s1Start) || isa<ObjCForCollectionStmt>(s1Start) ||
2133 isa<CXXForRangeStmt>(s1Start)))
2136 // Is s1End the branch condition?
2137 if (!isConditionForTerminator(s1Start, s1End))
2140 // Perform the hoisting by eliminating (2) and changing the start
2142 PieceNextI->setStartLocation(PieceI->getStartLocation());
2143 I = pieces.erase(I);
2147 /// Returns the number of bytes in the given (character-based) SourceRange.
2149 /// If the locations in the range are not on the same line, returns None.
2151 /// Note that this does not do a precise user-visible character or column count.
2152 static Optional<size_t> getLengthOnSingleLine(SourceManager &SM,
2153 SourceRange Range) {
2154 SourceRange ExpansionRange(SM.getExpansionLoc(Range.getBegin()),
2155 SM.getExpansionRange(Range.getEnd()).second);
2157 FileID FID = SM.getFileID(ExpansionRange.getBegin());
2158 if (FID != SM.getFileID(ExpansionRange.getEnd()))
2162 const llvm::MemoryBuffer *Buffer = SM.getBuffer(FID, &Invalid);
2166 unsigned BeginOffset = SM.getFileOffset(ExpansionRange.getBegin());
2167 unsigned EndOffset = SM.getFileOffset(ExpansionRange.getEnd());
2168 StringRef Snippet = Buffer->getBuffer().slice(BeginOffset, EndOffset);
2170 // We're searching the raw bytes of the buffer here, which might include
2171 // escaped newlines and such. That's okay; we're trying to decide whether the
2172 // SourceRange is covering a large or small amount of space in the user's
2174 if (Snippet.find_first_of("\r\n") != StringRef::npos)
2177 // This isn't Unicode-aware, but it doesn't need to be.
2178 return Snippet.size();
2181 /// \sa getLengthOnSingleLine(SourceManager, SourceRange)
2182 static Optional<size_t> getLengthOnSingleLine(SourceManager &SM,
2184 return getLengthOnSingleLine(SM, S->getSourceRange());
2187 /// Eliminate two-edge cycles created by addContextEdges().
2189 /// Once all the context edges are in place, there are plenty of cases where
2190 /// there's a single edge from a top-level statement to a subexpression,
2191 /// followed by a single path note, and then a reverse edge to get back out to
2192 /// the top level. If the statement is simple enough, the subexpression edges
2193 /// just add noise and make it harder to understand what's going on.
2195 /// This function only removes edges in pairs, because removing only one edge
2196 /// might leave other edges dangling.
2198 /// This will not remove edges in more complicated situations:
2199 /// - if there is more than one "hop" leading to or from a subexpression.
2200 /// - if there is an inlined call between the edges instead of a single event.
2201 /// - if the whole statement is large enough that having subexpression arrows
2202 /// might be helpful.
2203 static void removeContextCycles(PathPieces &Path, SourceManager &SM,
2205 for (PathPieces::iterator I = Path.begin(), E = Path.end(); I != E; ) {
2206 // Pattern match the current piece and its successor.
2207 PathDiagnosticControlFlowPiece *PieceI =
2208 dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
2215 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation());
2216 const Stmt *s1End = getLocStmt(PieceI->getEndLocation());
2218 PathPieces::iterator NextI = I; ++NextI;
2222 PathDiagnosticControlFlowPiece *PieceNextI =
2223 dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
2226 if (isa<PathDiagnosticEventPiece>(NextI->get())) {
2230 PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
2239 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation());
2240 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation());
2242 if (s1Start && s2Start && s1Start == s2End && s2Start == s1End) {
2243 const size_t MAX_SHORT_LINE_LENGTH = 80;
2244 Optional<size_t> s1Length = getLengthOnSingleLine(SM, s1Start);
2245 if (s1Length && *s1Length <= MAX_SHORT_LINE_LENGTH) {
2246 Optional<size_t> s2Length = getLengthOnSingleLine(SM, s2Start);
2247 if (s2Length && *s2Length <= MAX_SHORT_LINE_LENGTH) {
2249 I = Path.erase(NextI);
2259 /// \brief Return true if X is contained by Y.
2260 static bool lexicalContains(ParentMap &PM,
2266 X = PM.getParent(X);
2271 // Remove short edges on the same line less than 3 columns in difference.
2272 static void removePunyEdges(PathPieces &path,
2276 bool erased = false;
2278 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E;
2283 auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
2288 const Stmt *start = getLocStmt(PieceI->getStartLocation());
2289 const Stmt *end = getLocStmt(PieceI->getEndLocation());
2294 const Stmt *endParent = PM.getParent(end);
2298 if (isConditionForTerminator(end, endParent))
2301 SourceLocation FirstLoc = start->getLocStart();
2302 SourceLocation SecondLoc = end->getLocStart();
2304 if (!SM.isWrittenInSameFile(FirstLoc, SecondLoc))
2306 if (SM.isBeforeInTranslationUnit(SecondLoc, FirstLoc))
2307 std::swap(SecondLoc, FirstLoc);
2309 SourceRange EdgeRange(FirstLoc, SecondLoc);
2310 Optional<size_t> ByteWidth = getLengthOnSingleLine(SM, EdgeRange);
2312 // If the statements are on different lines, continue.
2316 const size_t MAX_PUNY_EDGE_LENGTH = 2;
2317 if (*ByteWidth <= MAX_PUNY_EDGE_LENGTH) {
2318 // FIXME: There are enough /bytes/ between the endpoints of the edge, but
2319 // there might not be enough /columns/. A proper user-visible column count
2320 // is probably too expensive, though.
2328 static void removeIdenticalEvents(PathPieces &path) {
2329 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ++I) {
2330 auto *PieceI = dyn_cast<PathDiagnosticEventPiece>(I->get());
2335 PathPieces::iterator NextI = I; ++NextI;
2339 auto *PieceNextI = dyn_cast<PathDiagnosticEventPiece>(NextI->get());
2344 // Erase the second piece if it has the same exact message text.
2345 if (PieceI->getString() == PieceNextI->getString()) {
2351 static bool optimizeEdges(PathPieces &path, SourceManager &SM,
2352 OptimizedCallsSet &OCS,
2353 LocationContextMap &LCM) {
2354 bool hasChanges = false;
2355 const LocationContext *LC = LCM[&path];
2357 ParentMap &PM = LC->getParentMap();
2359 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ) {
2360 // Optimize subpaths.
2361 if (auto *CallI = dyn_cast<PathDiagnosticCallPiece>(I->get())) {
2362 // Record the fact that a call has been optimized so we only do the
2364 if (!OCS.count(CallI)) {
2365 while (optimizeEdges(CallI->path, SM, OCS, LCM)) {}
2372 // Pattern match the current piece and its successor.
2373 auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
2380 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation());
2381 const Stmt *s1End = getLocStmt(PieceI->getEndLocation());
2382 const Stmt *level1 = getStmtParent(s1Start, PM);
2383 const Stmt *level2 = getStmtParent(s1End, PM);
2385 PathPieces::iterator NextI = I; ++NextI;
2389 auto *PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
2396 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation());
2397 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation());
2398 const Stmt *level3 = getStmtParent(s2Start, PM);
2399 const Stmt *level4 = getStmtParent(s2End, PM);
2403 // If we have two consecutive control edges whose end/begin locations
2404 // are at the same level (e.g. statements or top-level expressions within
2405 // a compound statement, or siblings share a single ancestor expression),
2406 // then merge them if they have no interesting intermediate event.
2410 // (1.1 -> 1.2) -> (1.2 -> 1.3) becomes (1.1 -> 1.3) because the common
2411 // parent is '1'. Here 'x.y.z' represents the hierarchy of statements.
2413 // NOTE: this will be limited later in cases where we add barriers
2414 // to prevent this optimization.
2416 if (level1 && level1 == level2 && level1 == level3 && level1 == level4) {
2417 PieceI->setEndLocation(PieceNextI->getEndLocation());
2425 // Eliminate edges between subexpressions and parent expressions
2426 // when the subexpression is consumed.
2428 // NOTE: this will be limited later in cases where we add barriers
2429 // to prevent this optimization.
2431 if (s1End && s1End == s2Start && level2) {
2432 bool removeEdge = false;
2433 // Remove edges into the increment or initialization of a
2434 // loop that have no interleaving event. This means that
2435 // they aren't interesting.
2436 if (isIncrementOrInitInForLoop(s1End, level2))
2438 // Next only consider edges that are not anchored on
2439 // the condition of a terminator. This are intermediate edges
2440 // that we might want to trim.
2441 else if (!isConditionForTerminator(level2, s1End)) {
2442 // Trim edges on expressions that are consumed by
2443 // the parent expression.
2444 if (isa<Expr>(s1End) && PM.isConsumedExpr(cast<Expr>(s1End))) {
2447 // Trim edges where a lexical containment doesn't exist.
2452 // If 'Z' lexically contains Y (it is an ancestor) and
2453 // 'X' does not lexically contain Y (it is a descendant OR
2454 // it has no lexical relationship at all) then trim.
2456 // This can eliminate edges where we dive into a subexpression
2457 // and then pop back out, etc.
2458 else if (s1Start && s2End &&
2459 lexicalContains(PM, s2Start, s2End) &&
2460 !lexicalContains(PM, s1End, s1Start)) {
2463 // Trim edges from a subexpression back to the top level if the
2464 // subexpression is on a different line.
2470 // These edges just look ugly and don't usually add anything.
2471 else if (s1Start && s2End &&
2472 lexicalContains(PM, s1Start, s1End)) {
2473 SourceRange EdgeRange(PieceI->getEndLocation().asLocation(),
2474 PieceI->getStartLocation().asLocation());
2475 if (!getLengthOnSingleLine(SM, EdgeRange).hasValue())
2481 PieceI->setEndLocation(PieceNextI->getEndLocation());
2488 // Optimize edges for ObjC fast-enumeration loops.
2490 // (X -> collection) -> (collection -> element)
2495 if (s1End == s2Start) {
2496 const ObjCForCollectionStmt *FS =
2497 dyn_cast_or_null<ObjCForCollectionStmt>(level3);
2498 if (FS && FS->getCollection()->IgnoreParens() == s2Start &&
2499 s2End == FS->getElement()) {
2500 PieceI->setEndLocation(PieceNextI->getEndLocation());
2507 // No changes at this index? Move to the next one.
2512 // Adjust edges into subexpressions to make them more uniform
2513 // and aesthetically pleasing.
2514 addContextEdges(path, SM, PM, LC);
2515 // Remove "cyclical" edges that include one or more context edges.
2516 removeContextCycles(path, SM, PM);
2517 // Hoist edges originating from branch conditions to branches
2518 // for simple branches.
2519 simplifySimpleBranches(path);
2520 // Remove any puny edges left over after primary optimization pass.
2521 removePunyEdges(path, SM, PM);
2522 // Remove identical events.
2523 removeIdenticalEvents(path);
2529 /// Drop the very first edge in a path, which should be a function entry edge.
2531 /// If the first edge is not a function entry edge (say, because the first
2532 /// statement had an invalid source location), this function does nothing.
2533 // FIXME: We should just generate invalid edges anyway and have the optimizer
2535 static void dropFunctionEntryEdge(PathPieces &Path,
2536 LocationContextMap &LCM,
2537 SourceManager &SM) {
2538 const auto *FirstEdge =
2539 dyn_cast<PathDiagnosticControlFlowPiece>(Path.front().get());
2543 const Decl *D = LCM[&Path]->getDecl();
2544 PathDiagnosticLocation EntryLoc = PathDiagnosticLocation::createBegin(D, SM);
2545 if (FirstEdge->getStartLocation() != EntryLoc)
2552 //===----------------------------------------------------------------------===//
2553 // Methods for BugType and subclasses.
2554 //===----------------------------------------------------------------------===//
2555 void BugType::anchor() { }
2557 void BugType::FlushReports(BugReporter &BR) {}
2559 void BuiltinBug::anchor() {}
2561 //===----------------------------------------------------------------------===//
2562 // Methods for BugReport and subclasses.
2563 //===----------------------------------------------------------------------===//
2565 void BugReport::NodeResolver::anchor() {}
2567 void BugReport::addVisitor(std::unique_ptr<BugReporterVisitor> visitor) {
2571 llvm::FoldingSetNodeID ID;
2572 visitor->Profile(ID);
2575 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos))
2578 CallbacksSet.InsertNode(visitor.get(), InsertPos);
2579 Callbacks.push_back(std::move(visitor));
2580 ++ConfigurationChangeToken;
2583 BugReport::~BugReport() {
2584 while (!interestingSymbols.empty()) {
2585 popInterestingSymbolsAndRegions();
2589 const Decl *BugReport::getDeclWithIssue() const {
2591 return DeclWithIssue;
2593 const ExplodedNode *N = getErrorNode();
2597 const LocationContext *LC = N->getLocationContext();
2598 return LC->getCurrentStackFrame()->getDecl();
2601 void BugReport::Profile(llvm::FoldingSetNodeID& hash) const {
2602 hash.AddPointer(&BT);
2603 hash.AddString(Description);
2604 PathDiagnosticLocation UL = getUniqueingLocation();
2607 } else if (Location.isValid()) {
2608 Location.Profile(hash);
2611 hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode));
2614 for (SourceRange range : Ranges) {
2615 if (!range.isValid())
2617 hash.AddInteger(range.getBegin().getRawEncoding());
2618 hash.AddInteger(range.getEnd().getRawEncoding());
2622 void BugReport::markInteresting(SymbolRef sym) {
2626 // If the symbol wasn't already in our set, note a configuration change.
2627 if (getInterestingSymbols().insert(sym).second)
2628 ++ConfigurationChangeToken;
2630 if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym))
2631 getInterestingRegions().insert(meta->getRegion());
2634 void BugReport::markInteresting(const MemRegion *R) {
2638 // If the base region wasn't already in our set, note a configuration change.
2639 R = R->getBaseRegion();
2640 if (getInterestingRegions().insert(R).second)
2641 ++ConfigurationChangeToken;
2643 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
2644 getInterestingSymbols().insert(SR->getSymbol());
2647 void BugReport::markInteresting(SVal V) {
2648 markInteresting(V.getAsRegion());
2649 markInteresting(V.getAsSymbol());
2652 void BugReport::markInteresting(const LocationContext *LC) {
2655 InterestingLocationContexts.insert(LC);
2658 bool BugReport::isInteresting(SVal V) {
2659 return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol());
2662 bool BugReport::isInteresting(SymbolRef sym) {
2665 // We don't currently consider metadata symbols to be interesting
2666 // even if we know their region is interesting. Is that correct behavior?
2667 return getInterestingSymbols().count(sym);
2670 bool BugReport::isInteresting(const MemRegion *R) {
2673 R = R->getBaseRegion();
2674 bool b = getInterestingRegions().count(R);
2677 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R))
2678 return getInterestingSymbols().count(SR->getSymbol());
2682 bool BugReport::isInteresting(const LocationContext *LC) {
2685 return InterestingLocationContexts.count(LC);
2688 void BugReport::lazyInitializeInterestingSets() {
2689 if (interestingSymbols.empty()) {
2690 interestingSymbols.push_back(new Symbols());
2691 interestingRegions.push_back(new Regions());
2695 BugReport::Symbols &BugReport::getInterestingSymbols() {
2696 lazyInitializeInterestingSets();
2697 return *interestingSymbols.back();
2700 BugReport::Regions &BugReport::getInterestingRegions() {
2701 lazyInitializeInterestingSets();
2702 return *interestingRegions.back();
2705 void BugReport::pushInterestingSymbolsAndRegions() {
2706 interestingSymbols.push_back(new Symbols(getInterestingSymbols()));
2707 interestingRegions.push_back(new Regions(getInterestingRegions()));
2710 void BugReport::popInterestingSymbolsAndRegions() {
2711 delete interestingSymbols.pop_back_val();
2712 delete interestingRegions.pop_back_val();
2715 const Stmt *BugReport::getStmt() const {
2719 ProgramPoint ProgP = ErrorNode->getLocation();
2720 const Stmt *S = nullptr;
2722 if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) {
2723 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit();
2724 if (BE->getBlock() == &Exit)
2725 S = GetPreviousStmt(ErrorNode);
2728 S = PathDiagnosticLocation::getStmt(ErrorNode);
2733 llvm::iterator_range<BugReport::ranges_iterator> BugReport::getRanges() {
2734 // If no custom ranges, add the range of the statement corresponding to
2736 if (Ranges.empty()) {
2737 if (const Expr *E = dyn_cast_or_null<Expr>(getStmt()))
2738 addRange(E->getSourceRange());
2740 return llvm::make_range(ranges_iterator(), ranges_iterator());
2743 // User-specified absence of range info.
2744 if (Ranges.size() == 1 && !Ranges.begin()->isValid())
2745 return llvm::make_range(ranges_iterator(), ranges_iterator());
2747 return llvm::make_range(Ranges.begin(), Ranges.end());
2750 PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const {
2752 assert(!Location.isValid() &&
2753 "Either Location or ErrorNode should be specified but not both.");
2754 return PathDiagnosticLocation::createEndOfPath(ErrorNode, SM);
2757 assert(Location.isValid());
2761 //===----------------------------------------------------------------------===//
2762 // Methods for BugReporter and subclasses.
2763 //===----------------------------------------------------------------------===//
2765 BugReportEquivClass::~BugReportEquivClass() { }
2766 GRBugReporter::~GRBugReporter() { }
2767 BugReporterData::~BugReporterData() {}
2769 ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); }
2771 ProgramStateManager&
2772 GRBugReporter::getStateManager() { return Eng.getStateManager(); }
2774 BugReporter::~BugReporter() {
2777 // Free the bug reports we are tracking.
2778 typedef std::vector<BugReportEquivClass *> ContTy;
2779 for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end();
2785 void BugReporter::FlushReports() {
2786 if (BugTypes.isEmpty())
2789 // First flush the warnings for each BugType. This may end up creating new
2790 // warnings and new BugTypes.
2791 // FIXME: Only NSErrorChecker needs BugType's FlushReports.
2792 // Turn NSErrorChecker into a proper checker and remove this.
2793 SmallVector<const BugType *, 16> bugTypes(BugTypes.begin(), BugTypes.end());
2794 for (SmallVectorImpl<const BugType *>::iterator
2795 I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I)
2796 const_cast<BugType*>(*I)->FlushReports(*this);
2798 // We need to flush reports in deterministic order to ensure the order
2799 // of the reports is consistent between runs.
2800 typedef std::vector<BugReportEquivClass *> ContVecTy;
2801 for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end();
2803 BugReportEquivClass& EQ = **EI;
2807 // BugReporter owns and deletes only BugTypes created implicitly through
2809 // FIXME: There are leaks from checkers that assume that the BugTypes they
2810 // create will be destroyed by the BugReporter.
2811 llvm::DeleteContainerSeconds(StrBugTypes);
2813 // Remove all references to the BugType objects.
2814 BugTypes = F.getEmptySet();
2817 //===----------------------------------------------------------------------===//
2818 // PathDiagnostics generation.
2819 //===----------------------------------------------------------------------===//
2822 /// A wrapper around a report graph, which contains only a single path, and its
2826 InterExplodedGraphMap BackMap;
2827 std::unique_ptr<ExplodedGraph> Graph;
2828 const ExplodedNode *ErrorNode;
2832 /// A wrapper around a trimmed graph and its node maps.
2833 class TrimmedGraph {
2834 InterExplodedGraphMap InverseMap;
2836 typedef llvm::DenseMap<const ExplodedNode *, unsigned> PriorityMapTy;
2837 PriorityMapTy PriorityMap;
2839 typedef std::pair<const ExplodedNode *, size_t> NodeIndexPair;
2840 SmallVector<NodeIndexPair, 32> ReportNodes;
2842 std::unique_ptr<ExplodedGraph> G;
2844 /// A helper class for sorting ExplodedNodes by priority.
2845 template <bool Descending>
2846 class PriorityCompare {
2847 const PriorityMapTy &PriorityMap;
2850 PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {}
2852 bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const {
2853 PriorityMapTy::const_iterator LI = PriorityMap.find(LHS);
2854 PriorityMapTy::const_iterator RI = PriorityMap.find(RHS);
2855 PriorityMapTy::const_iterator E = PriorityMap.end();
2862 return Descending ? LI->second > RI->second
2863 : LI->second < RI->second;
2866 bool operator()(const NodeIndexPair &LHS, const NodeIndexPair &RHS) const {
2867 return (*this)(LHS.first, RHS.first);
2872 TrimmedGraph(const ExplodedGraph *OriginalGraph,
2873 ArrayRef<const ExplodedNode *> Nodes);
2875 bool popNextReportGraph(ReportGraph &GraphWrapper);
2879 TrimmedGraph::TrimmedGraph(const ExplodedGraph *OriginalGraph,
2880 ArrayRef<const ExplodedNode *> Nodes) {
2881 // The trimmed graph is created in the body of the constructor to ensure
2882 // that the DenseMaps have been initialized already.
2883 InterExplodedGraphMap ForwardMap;
2884 G = OriginalGraph->trim(Nodes, &ForwardMap, &InverseMap);
2886 // Find the (first) error node in the trimmed graph. We just need to consult
2887 // the node map which maps from nodes in the original graph to nodes
2888 // in the new graph.
2889 llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes;
2891 for (unsigned i = 0, count = Nodes.size(); i < count; ++i) {
2892 if (const ExplodedNode *NewNode = ForwardMap.lookup(Nodes[i])) {
2893 ReportNodes.push_back(std::make_pair(NewNode, i));
2894 RemainingNodes.insert(NewNode);
2898 assert(!RemainingNodes.empty() && "No error node found in the trimmed graph");
2900 // Perform a forward BFS to find all the shortest paths.
2901 std::queue<const ExplodedNode *> WS;
2903 assert(G->num_roots() == 1);
2904 WS.push(*G->roots_begin());
2905 unsigned Priority = 0;
2907 while (!WS.empty()) {
2908 const ExplodedNode *Node = WS.front();
2911 PriorityMapTy::iterator PriorityEntry;
2913 std::tie(PriorityEntry, IsNew) =
2914 PriorityMap.insert(std::make_pair(Node, Priority));
2918 assert(PriorityEntry->second <= Priority);
2922 if (RemainingNodes.erase(Node))
2923 if (RemainingNodes.empty())
2926 for (ExplodedNode::const_pred_iterator I = Node->succ_begin(),
2927 E = Node->succ_end();
2932 // Sort the error paths from longest to shortest.
2933 std::sort(ReportNodes.begin(), ReportNodes.end(),
2934 PriorityCompare<true>(PriorityMap));
2937 bool TrimmedGraph::popNextReportGraph(ReportGraph &GraphWrapper) {
2938 if (ReportNodes.empty())
2941 const ExplodedNode *OrigN;
2942 std::tie(OrigN, GraphWrapper.Index) = ReportNodes.pop_back_val();
2943 assert(PriorityMap.find(OrigN) != PriorityMap.end() &&
2944 "error node not accessible from root");
2946 // Create a new graph with a single path. This is the graph
2947 // that will be returned to the caller.
2948 auto GNew = llvm::make_unique<ExplodedGraph>();
2949 GraphWrapper.BackMap.clear();
2951 // Now walk from the error node up the BFS path, always taking the
2952 // predeccessor with the lowest number.
2953 ExplodedNode *Succ = nullptr;
2955 // Create the equivalent node in the new graph with the same state
2957 ExplodedNode *NewN = GNew->createUncachedNode(OrigN->getLocation(), OrigN->getState(),
2960 // Store the mapping to the original node.
2961 InterExplodedGraphMap::const_iterator IMitr = InverseMap.find(OrigN);
2962 assert(IMitr != InverseMap.end() && "No mapping to original node.");
2963 GraphWrapper.BackMap[NewN] = IMitr->second;
2965 // Link up the new node with the previous node.
2967 Succ->addPredecessor(NewN, *GNew);
2969 GraphWrapper.ErrorNode = NewN;
2973 // Are we at the final node?
2974 if (OrigN->pred_empty()) {
2975 GNew->addRoot(NewN);
2979 // Find the next predeccessor node. We choose the node that is marked
2980 // with the lowest BFS number.
2981 OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(),
2982 PriorityCompare<false>(PriorityMap));
2985 GraphWrapper.Graph = std::move(GNew);
2991 /// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object
2992 /// and collapses PathDiagosticPieces that are expanded by macros.
2993 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) {
2994 typedef std::vector<
2995 std::pair<std::shared_ptr<PathDiagnosticMacroPiece>, SourceLocation>>
2998 typedef std::vector<std::shared_ptr<PathDiagnosticPiece>> PiecesTy;
3000 MacroStackTy MacroStack;
3003 for (PathPieces::const_iterator I = path.begin(), E = path.end();
3008 // Recursively compact calls.
3009 if (auto *call = dyn_cast<PathDiagnosticCallPiece>(&*piece)) {
3010 CompactPathDiagnostic(call->path, SM);
3013 // Get the location of the PathDiagnosticPiece.
3014 const FullSourceLoc Loc = piece->getLocation().asLocation();
3016 // Determine the instantiation location, which is the location we group
3017 // related PathDiagnosticPieces.
3018 SourceLocation InstantiationLoc = Loc.isMacroID() ?
3019 SM.getExpansionLoc(Loc) :
3022 if (Loc.isFileID()) {
3024 Pieces.push_back(piece);
3028 assert(Loc.isMacroID());
3030 // Is the PathDiagnosticPiece within the same macro group?
3031 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) {
3032 MacroStack.back().first->subPieces.push_back(piece);
3036 // We aren't in the same group. Are we descending into a new macro
3037 // or are part of an old one?
3038 std::shared_ptr<PathDiagnosticMacroPiece> MacroGroup;
3040 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ?
3041 SM.getExpansionLoc(Loc) :
3044 // Walk the entire macro stack.
3045 while (!MacroStack.empty()) {
3046 if (InstantiationLoc == MacroStack.back().second) {
3047 MacroGroup = MacroStack.back().first;
3051 if (ParentInstantiationLoc == MacroStack.back().second) {
3052 MacroGroup = MacroStack.back().first;
3056 MacroStack.pop_back();
3059 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) {
3060 // Create a new macro group and add it to the stack.
3061 auto NewGroup = std::make_shared<PathDiagnosticMacroPiece>(
3062 PathDiagnosticLocation::createSingleLocation(piece->getLocation()));
3065 MacroGroup->subPieces.push_back(NewGroup);
3067 assert(InstantiationLoc.isFileID());
3068 Pieces.push_back(NewGroup);
3071 MacroGroup = NewGroup;
3072 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc));
3075 // Finally, add the PathDiagnosticPiece to the group.
3076 MacroGroup->subPieces.push_back(piece);
3079 // Now take the pieces and construct a new PathDiagnostic.
3082 path.insert(path.end(), Pieces.begin(), Pieces.end());
3085 bool GRBugReporter::generatePathDiagnostic(PathDiagnostic& PD,
3086 PathDiagnosticConsumer &PC,
3087 ArrayRef<BugReport *> &bugReports) {
3088 assert(!bugReports.empty());
3090 bool HasValid = false;
3091 bool HasInvalid = false;
3092 SmallVector<const ExplodedNode *, 32> errorNodes;
3093 for (ArrayRef<BugReport*>::iterator I = bugReports.begin(),
3094 E = bugReports.end(); I != E; ++I) {
3095 if ((*I)->isValid()) {
3097 errorNodes.push_back((*I)->getErrorNode());
3099 // Keep the errorNodes list in sync with the bugReports list.
3101 errorNodes.push_back(nullptr);
3105 // If all the reports have been marked invalid by a previous path generation,
3110 typedef PathDiagnosticConsumer::PathGenerationScheme PathGenerationScheme;
3111 PathGenerationScheme ActiveScheme = PC.getGenerationScheme();
3113 if (ActiveScheme == PathDiagnosticConsumer::Extensive) {
3114 AnalyzerOptions &options = getAnalyzerOptions();
3115 if (options.getBooleanOption("path-diagnostics-alternate", true)) {
3116 ActiveScheme = PathDiagnosticConsumer::AlternateExtensive;
3120 TrimmedGraph TrimG(&getGraph(), errorNodes);
3121 ReportGraph ErrorGraph;
3123 while (TrimG.popNextReportGraph(ErrorGraph)) {
3124 // Find the BugReport with the original location.
3125 assert(ErrorGraph.Index < bugReports.size());
3126 BugReport *R = bugReports[ErrorGraph.Index];
3127 assert(R && "No original report found for sliced graph.");
3128 assert(R->isValid() && "Report selected by trimmed graph marked invalid.");
3130 // Start building the path diagnostic...
3131 PathDiagnosticBuilder PDB(*this, R, ErrorGraph.BackMap, &PC);
3132 const ExplodedNode *N = ErrorGraph.ErrorNode;
3134 // Register additional node visitors.
3135 R->addVisitor(llvm::make_unique<NilReceiverBRVisitor>());
3136 R->addVisitor(llvm::make_unique<ConditionBRVisitor>());
3137 R->addVisitor(llvm::make_unique<LikelyFalsePositiveSuppressionBRVisitor>());
3138 R->addVisitor(llvm::make_unique<CXXSelfAssignmentBRVisitor>());
3140 BugReport::VisitorList visitors;
3141 unsigned origReportConfigToken, finalReportConfigToken;
3142 LocationContextMap LCM;
3144 // While generating diagnostics, it's possible the visitors will decide
3145 // new symbols and regions are interesting, or add other visitors based on
3146 // the information they find. If they do, we need to regenerate the path
3147 // based on our new report configuration.
3149 // Get a clean copy of all the visitors.
3150 for (BugReport::visitor_iterator I = R->visitor_begin(),
3151 E = R->visitor_end(); I != E; ++I)
3152 visitors.push_back((*I)->clone());
3154 // Clear out the active path from any previous work.
3156 origReportConfigToken = R->getConfigurationChangeToken();
3158 // Generate the very last diagnostic piece - the piece is visible before
3159 // the trace is expanded.
3160 std::unique_ptr<PathDiagnosticPiece> LastPiece;
3161 for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end();
3163 if (std::unique_ptr<PathDiagnosticPiece> Piece =
3164 (*I)->getEndPath(PDB, N, *R)) {
3165 assert (!LastPiece &&
3166 "There can only be one final piece in a diagnostic.");
3167 LastPiece = std::move(Piece);
3171 if (ActiveScheme != PathDiagnosticConsumer::None) {
3173 LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R);
3175 PD.setEndOfPath(std::move(LastPiece));
3178 // Make sure we get a clean location context map so we don't
3179 // hold onto old mappings.
3182 switch (ActiveScheme) {
3183 case PathDiagnosticConsumer::AlternateExtensive:
3184 GenerateAlternateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors);
3186 case PathDiagnosticConsumer::Extensive:
3187 GenerateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors);
3189 case PathDiagnosticConsumer::Minimal:
3190 GenerateMinimalPathDiagnostic(PD, PDB, N, LCM, visitors);
3192 case PathDiagnosticConsumer::None:
3193 GenerateVisitorsOnlyPathDiagnostic(PD, PDB, N, visitors);
3197 // Clean up the visitors we used.
3200 // Did anything change while generating this path?
3201 finalReportConfigToken = R->getConfigurationChangeToken();
3202 } while (finalReportConfigToken != origReportConfigToken);
3207 // Finally, prune the diagnostic path of uninteresting stuff.
3208 if (!PD.path.empty()) {
3209 if (R->shouldPrunePath() && getAnalyzerOptions().shouldPrunePaths()) {
3210 bool stillHasNotes = removeUnneededCalls(PD.getMutablePieces(), R, LCM);
3211 assert(stillHasNotes);
3212 (void)stillHasNotes;
3215 // Redirect all call pieces to have valid locations.
3216 adjustCallLocations(PD.getMutablePieces());
3217 removePiecesWithInvalidLocations(PD.getMutablePieces());
3219 if (ActiveScheme == PathDiagnosticConsumer::AlternateExtensive) {
3220 SourceManager &SM = getSourceManager();
3222 // Reduce the number of edges from a very conservative set
3223 // to an aesthetically pleasing subset that conveys the
3224 // necessary information.
3225 OptimizedCallsSet OCS;
3226 while (optimizeEdges(PD.getMutablePieces(), SM, OCS, LCM)) {}
3228 // Drop the very first function-entry edge. It's not really necessary
3229 // for top-level functions.
3230 dropFunctionEntryEdge(PD.getMutablePieces(), LCM, SM);
3233 // Remove messages that are basically the same, and edges that may not
3235 // We have to do this after edge optimization in the Extensive mode.
3236 removeRedundantMsgs(PD.getMutablePieces());
3237 removeEdgesToDefaultInitializers(PD.getMutablePieces());
3240 // We found a report and didn't suppress it.
3244 // We suppressed all the reports in this equivalence class.
3245 assert(!HasInvalid && "Inconsistent suppression");
3250 void BugReporter::Register(BugType *BT) {
3251 BugTypes = F.add(BugTypes, BT);
3254 void BugReporter::emitReport(std::unique_ptr<BugReport> R) {
3255 if (const ExplodedNode *E = R->getErrorNode()) {
3256 // An error node must either be a sink or have a tag, otherwise
3257 // it could get reclaimed before the path diagnostic is created.
3258 assert((E->isSink() || E->getLocation().getTag()) &&
3259 "Error node must either be a sink or have a tag");
3261 const AnalysisDeclContext *DeclCtx =
3262 E->getLocationContext()->getAnalysisDeclContext();
3263 // The source of autosynthesized body can be handcrafted AST or a model
3264 // file. The locations from handcrafted ASTs have no valid source locations
3265 // and have to be discarded. Locations from model files should be preserved
3266 // for processing and reporting.
3267 if (DeclCtx->isBodyAutosynthesized() &&
3268 !DeclCtx->isBodyAutosynthesizedFromModelFile())
3272 bool ValidSourceLoc = R->getLocation(getSourceManager()).isValid();
3273 assert(ValidSourceLoc);
3274 // If we mess up in a release build, we'd still prefer to just drop the bug
3275 // instead of trying to go on.
3276 if (!ValidSourceLoc)
3279 // Compute the bug report's hash to determine its equivalence class.
3280 llvm::FoldingSetNodeID ID;
3283 // Lookup the equivance class. If there isn't one, create it.
3284 BugType& BT = R->getBugType();
3287 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos);
3290 EQ = new BugReportEquivClass(std::move(R));
3291 EQClasses.InsertNode(EQ, InsertPos);
3292 EQClassesVector.push_back(EQ);
3294 EQ->AddReport(std::move(R));
3298 //===----------------------------------------------------------------------===//
3299 // Emitting reports in equivalence classes.
3300 //===----------------------------------------------------------------------===//
3303 struct FRIEC_WLItem {
3304 const ExplodedNode *N;
3305 ExplodedNode::const_succ_iterator I, E;
3307 FRIEC_WLItem(const ExplodedNode *n)
3308 : N(n), I(N->succ_begin()), E(N->succ_end()) {}
3312 static const CFGBlock *findBlockForNode(const ExplodedNode *N) {
3313 ProgramPoint P = N->getLocation();
3314 if (auto BEP = P.getAs<BlockEntrance>())
3315 return BEP->getBlock();
3317 // Find the node's current statement in the CFG.
3318 if (const Stmt *S = PathDiagnosticLocation::getStmt(N))
3319 return N->getLocationContext()->getAnalysisDeclContext()
3320 ->getCFGStmtMap()->getBlock(S);
3325 // Returns true if by simply looking at the block, we can be sure that it
3326 // results in a sink during analysis. This is useful to know when the analysis
3327 // was interrupted, and we try to figure out if it would sink eventually.
3328 // There may be many more reasons why a sink would appear during analysis
3329 // (eg. checkers may generate sinks arbitrarily), but here we only consider
3330 // sinks that would be obvious by looking at the CFG.
3331 static bool isImmediateSinkBlock(const CFGBlock *Blk) {
3332 if (Blk->hasNoReturnElement())
3335 // FIXME: Throw-expressions are currently generating sinks during analysis:
3336 // they're not supported yet, and also often used for actually terminating
3337 // the program. So we should treat them as sinks in this analysis as well,
3338 // at least for now, but once we have better support for exceptions,
3339 // we'd need to carefully handle the case when the throw is being
3340 // immediately caught.
3341 if (std::any_of(Blk->begin(), Blk->end(), [](const CFGElement &Elm) {
3342 if (Optional<CFGStmt> StmtElm = Elm.getAs<CFGStmt>())
3343 if (isa<CXXThrowExpr>(StmtElm->getStmt()))
3352 // Returns true if by looking at the CFG surrounding the node's program
3353 // point, we can be sure that any analysis starting from this point would
3354 // eventually end with a sink. We scan the child CFG blocks in a depth-first
3355 // manner and see if all paths eventually end up in an immediate sink block.
3356 static bool isInevitablySinking(const ExplodedNode *N) {
3357 const CFG &Cfg = N->getCFG();
3359 const CFGBlock *StartBlk = findBlockForNode(N);
3362 if (isImmediateSinkBlock(StartBlk))
3365 llvm::SmallVector<const CFGBlock *, 32> DFSWorkList;
3366 llvm::SmallPtrSet<const CFGBlock *, 32> Visited;
3368 DFSWorkList.push_back(StartBlk);
3369 while (!DFSWorkList.empty()) {
3370 const CFGBlock *Blk = DFSWorkList.back();
3371 DFSWorkList.pop_back();
3372 Visited.insert(Blk);
3374 for (const auto &Succ : Blk->succs()) {
3375 if (const CFGBlock *SuccBlk = Succ.getReachableBlock()) {
3376 if (SuccBlk == &Cfg.getExit()) {
3377 // If at least one path reaches the CFG exit, it means that control is
3378 // returned to the caller. For now, say that we are not sure what
3379 // happens next. If necessary, this can be improved to analyze
3380 // the parent StackFrameContext's call site in a similar manner.
3384 if (!isImmediateSinkBlock(SuccBlk) && !Visited.count(SuccBlk)) {
3385 // If the block has reachable child blocks that aren't no-return,
3386 // add them to the worklist.
3387 DFSWorkList.push_back(SuccBlk);
3393 // Nothing reached the exit. It can only mean one thing: there's no return.
3398 FindReportInEquivalenceClass(BugReportEquivClass& EQ,
3399 SmallVectorImpl<BugReport*> &bugReports) {
3401 BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end();
3403 BugType& BT = I->getBugType();
3405 // If we don't need to suppress any of the nodes because they are
3406 // post-dominated by a sink, simply add all the nodes in the equivalence class
3407 // to 'Nodes'. Any of the reports will serve as a "representative" report.
3408 if (!BT.isSuppressOnSink()) {
3410 for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) {
3411 const ExplodedNode *N = I->getErrorNode();
3414 bugReports.push_back(R);
3420 // For bug reports that should be suppressed when all paths are post-dominated
3421 // by a sink node, iterate through the reports in the equivalence class
3422 // until we find one that isn't post-dominated (if one exists). We use a
3423 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write
3424 // this as a recursive function, but we don't want to risk blowing out the
3425 // stack for very long paths.
3426 BugReport *exampleReport = nullptr;
3428 for (; I != E; ++I) {
3429 const ExplodedNode *errorNode = I->getErrorNode();
3433 if (errorNode->isSink()) {
3435 "BugType::isSuppressSink() should not be 'true' for sink end nodes");
3437 // No successors? By definition this nodes isn't post-dominated by a sink.
3438 if (errorNode->succ_empty()) {
3439 bugReports.push_back(&*I);
3441 exampleReport = &*I;
3445 // See if we are in a no-return CFG block. If so, treat this similarly
3446 // to being post-dominated by a sink. This works better when the analysis
3447 // is incomplete and we have never reached the no-return function call(s)
3448 // that we'd inevitably bump into on this path.
3449 if (isInevitablySinking(errorNode))
3452 // At this point we know that 'N' is not a sink and it has at least one
3453 // successor. Use a DFS worklist to find a non-sink end-of-path node.
3454 typedef FRIEC_WLItem WLItem;
3455 typedef SmallVector<WLItem, 10> DFSWorkList;
3456 llvm::DenseMap<const ExplodedNode *, unsigned> Visited;
3459 WL.push_back(errorNode);
3460 Visited[errorNode] = 1;
3462 while (!WL.empty()) {
3463 WLItem &WI = WL.back();
3464 assert(!WI.N->succ_empty());
3466 for (; WI.I != WI.E; ++WI.I) {
3467 const ExplodedNode *Succ = *WI.I;
3468 // End-of-path node?
3469 if (Succ->succ_empty()) {
3470 // If we found an end-of-path node that is not a sink.
3471 if (!Succ->isSink()) {
3472 bugReports.push_back(&*I);
3474 exampleReport = &*I;
3478 // Found a sink? Continue on to the next successor.
3481 // Mark the successor as visited. If it hasn't been explored,
3482 // enqueue it to the DFS worklist.
3483 unsigned &mark = Visited[Succ];
3491 // The worklist may have been cleared at this point. First
3492 // check if it is empty before checking the last item.
3493 if (!WL.empty() && &WL.back() == &WI)
3498 // ExampleReport will be NULL if all the nodes in the equivalence class
3499 // were post-dominated by sinks.
3500 return exampleReport;
3503 void BugReporter::FlushReport(BugReportEquivClass& EQ) {
3504 SmallVector<BugReport*, 10> bugReports;
3505 BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports);
3506 if (exampleReport) {
3507 for (PathDiagnosticConsumer *PDC : getPathDiagnosticConsumers()) {
3508 FlushReport(exampleReport, *PDC, bugReports);
3513 void BugReporter::FlushReport(BugReport *exampleReport,
3514 PathDiagnosticConsumer &PD,
3515 ArrayRef<BugReport*> bugReports) {
3517 // FIXME: Make sure we use the 'R' for the path that was actually used.
3518 // Probably doesn't make a difference in practice.
3519 BugType& BT = exampleReport->getBugType();
3521 std::unique_ptr<PathDiagnostic> D(new PathDiagnostic(
3522 exampleReport->getBugType().getCheckName(),
3523 exampleReport->getDeclWithIssue(), exampleReport->getBugType().getName(),
3524 exampleReport->getDescription(),
3525 exampleReport->getShortDescription(/*Fallback=*/false), BT.getCategory(),
3526 exampleReport->getUniqueingLocation(),
3527 exampleReport->getUniqueingDecl()));
3529 if (exampleReport->isPathSensitive()) {
3530 // Generate the full path diagnostic, using the generation scheme
3531 // specified by the PathDiagnosticConsumer. Note that we have to generate
3532 // path diagnostics even for consumers which do not support paths, because
3533 // the BugReporterVisitors may mark this bug as a false positive.
3534 assert(!bugReports.empty());
3536 MaxBugClassSize.updateMax(bugReports.size());
3538 if (!generatePathDiagnostic(*D.get(), PD, bugReports))
3541 MaxValidBugClassSize.updateMax(bugReports.size());
3543 // Examine the report and see if the last piece is in a header. Reset the
3544 // report location to the last piece in the main source file.
3545 AnalyzerOptions &Opts = getAnalyzerOptions();
3546 if (Opts.shouldReportIssuesInMainSourceFile() && !Opts.AnalyzeAll)
3547 D->resetDiagnosticLocationToMainFile();
3550 // If the path is empty, generate a single step path with the location
3552 if (D->path.empty()) {
3553 PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager());
3554 auto piece = llvm::make_unique<PathDiagnosticEventPiece>(
3555 L, exampleReport->getDescription());
3556 for (SourceRange Range : exampleReport->getRanges())
3557 piece->addRange(Range);
3558 D->setEndOfPath(std::move(piece));
3561 PathPieces &Pieces = D->getMutablePieces();
3562 if (getAnalyzerOptions().shouldDisplayNotesAsEvents()) {
3563 // For path diagnostic consumers that don't support extra notes,
3564 // we may optionally convert those to path notes.
3565 for (auto I = exampleReport->getNotes().rbegin(),
3566 E = exampleReport->getNotes().rend(); I != E; ++I) {
3567 PathDiagnosticNotePiece *Piece = I->get();
3568 auto ConvertedPiece = std::make_shared<PathDiagnosticEventPiece>(
3569 Piece->getLocation(), Piece->getString());
3570 for (const auto &R: Piece->getRanges())
3571 ConvertedPiece->addRange(R);
3573 Pieces.push_front(std::move(ConvertedPiece));
3576 for (auto I = exampleReport->getNotes().rbegin(),
3577 E = exampleReport->getNotes().rend(); I != E; ++I)
3578 Pieces.push_front(*I);
3581 // Get the meta data.
3582 const BugReport::ExtraTextList &Meta = exampleReport->getExtraText();
3583 for (BugReport::ExtraTextList::const_iterator i = Meta.begin(),
3584 e = Meta.end(); i != e; ++i) {
3588 PD.HandlePathDiagnostic(std::move(D));
3591 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue,
3592 const CheckerBase *Checker,
3593 StringRef Name, StringRef Category,
3594 StringRef Str, PathDiagnosticLocation Loc,
3595 ArrayRef<SourceRange> Ranges) {
3596 EmitBasicReport(DeclWithIssue, Checker->getCheckName(), Name, Category, Str,
3599 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue,
3600 CheckName CheckName,
3601 StringRef name, StringRef category,
3602 StringRef str, PathDiagnosticLocation Loc,
3603 ArrayRef<SourceRange> Ranges) {
3605 // 'BT' is owned by BugReporter.
3606 BugType *BT = getBugTypeForName(CheckName, name, category);
3607 auto R = llvm::make_unique<BugReport>(*BT, str, Loc);
3608 R->setDeclWithIssue(DeclWithIssue);
3609 for (ArrayRef<SourceRange>::iterator I = Ranges.begin(), E = Ranges.end();
3612 emitReport(std::move(R));
3615 BugType *BugReporter::getBugTypeForName(CheckName CheckName, StringRef name,
3616 StringRef category) {
3617 SmallString<136> fullDesc;
3618 llvm::raw_svector_ostream(fullDesc) << CheckName.getName() << ":" << name
3620 BugType *&BT = StrBugTypes[fullDesc];
3622 BT = new BugType(CheckName, name, category);
3626 LLVM_DUMP_METHOD void PathPieces::dump() const {
3628 for (PathPieces::const_iterator I = begin(), E = end(); I != E; ++I) {
3629 llvm::errs() << "[" << index++ << "] ";
3631 llvm::errs() << "\n";
3635 LLVM_DUMP_METHOD void PathDiagnosticCallPiece::dump() const {
3636 llvm::errs() << "CALL\n--------------\n";
3638 if (const Stmt *SLoc = getLocStmt(getLocation()))
3640 else if (const NamedDecl *ND = dyn_cast<NamedDecl>(getCallee()))
3641 llvm::errs() << *ND << "\n";
3643 getLocation().dump();
3646 LLVM_DUMP_METHOD void PathDiagnosticEventPiece::dump() const {
3647 llvm::errs() << "EVENT\n--------------\n";
3648 llvm::errs() << getString() << "\n";
3649 llvm::errs() << " ---- at ----\n";
3650 getLocation().dump();
3653 LLVM_DUMP_METHOD void PathDiagnosticControlFlowPiece::dump() const {
3654 llvm::errs() << "CONTROL\n--------------\n";
3655 getStartLocation().dump();
3656 llvm::errs() << " ---- to ----\n";
3657 getEndLocation().dump();
3660 LLVM_DUMP_METHOD void PathDiagnosticMacroPiece::dump() const {
3661 llvm::errs() << "MACRO\n--------------\n";
3662 // FIXME: Print which macro is being invoked.
3665 LLVM_DUMP_METHOD void PathDiagnosticNotePiece::dump() const {
3666 llvm::errs() << "NOTE\n--------------\n";
3667 llvm::errs() << getString() << "\n";
3668 llvm::errs() << " ---- at ----\n";
3669 getLocation().dump();
3672 LLVM_DUMP_METHOD void PathDiagnosticLocation::dump() const {
3674 llvm::errs() << "<INVALID>\n";
3680 // FIXME: actually print the range.
3681 llvm::errs() << "<range>\n";
3684 asLocation().dump();
3685 llvm::errs() << "\n";
3691 llvm::errs() << "<NULL STMT>\n";
3694 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(D))
3695 llvm::errs() << *ND << "\n";
3696 else if (isa<BlockDecl>(D))
3697 // FIXME: Make this nicer.
3698 llvm::errs() << "<block>\n";
3700 llvm::errs() << "<unknown decl>\n";
3702 llvm::errs() << "<NULL DECL>\n";