1 //===- BugReporter.cpp - Generate PathDiagnostics for bugs ----------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines BugReporter, a utility class for generating
10 // PathDiagnostics.
11 //
12 //===----------------------------------------------------------------------===//
13
14 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h"
15 #include "clang/AST/Decl.h"
16 #include "clang/AST/DeclBase.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/Stmt.h"
22 #include "clang/AST/StmtCXX.h"
23 #include "clang/AST/StmtObjC.h"
24 #include "clang/Analysis/AnalysisDeclContext.h"
25 #include "clang/Analysis/CFG.h"
26 #include "clang/Analysis/CFGStmtMap.h"
27 #include "clang/Analysis/PathDiagnostic.h"
28 #include "clang/Analysis/ProgramPoint.h"
29 #include "clang/Basic/LLVM.h"
30 #include "clang/Basic/SourceLocation.h"
31 #include "clang/Basic/SourceManager.h"
32 #include "clang/StaticAnalyzer/Core/AnalyzerOptions.h"
33 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporterVisitors.h"
34 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
35 #include "clang/StaticAnalyzer/Core/Checker.h"
36 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
37 #include "clang/StaticAnalyzer/Core/CheckerRegistryData.h"
38 #include "clang/StaticAnalyzer/Core/PathSensitive/ExplodedGraph.h"
39 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
40 #include "clang/StaticAnalyzer/Core/PathSensitive/MemRegion.h"
41 #include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
42 #include "clang/StaticAnalyzer/Core/PathSensitive/SMTConv.h"
43 #include "clang/StaticAnalyzer/Core/PathSensitive/SVals.h"
44 #include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
45 #include "llvm/ADT/ArrayRef.h"
46 #include "llvm/ADT/DenseMap.h"
47 #include "llvm/ADT/DenseSet.h"
48 #include "llvm/ADT/FoldingSet.h"
49 #include "llvm/ADT/None.h"
50 #include "llvm/ADT/Optional.h"
51 #include "llvm/ADT/STLExtras.h"
52 #include "llvm/ADT/SmallPtrSet.h"
53 #include "llvm/ADT/SmallString.h"
54 #include "llvm/ADT/SmallVector.h"
55 #include "llvm/ADT/Statistic.h"
56 #include "llvm/ADT/StringExtras.h"
57 #include "llvm/ADT/StringRef.h"
58 #include "llvm/ADT/iterator_range.h"
59 #include "llvm/Support/Casting.h"
60 #include "llvm/Support/Compiler.h"
61 #include "llvm/Support/ErrorHandling.h"
62 #include "llvm/Support/MemoryBuffer.h"
63 #include "llvm/Support/raw_ostream.h"
64 #include <algorithm>
65 #include <cassert>
66 #include <cstddef>
67 #include <iterator>
68 #include <memory>
69 #include <queue>
70 #include <string>
71 #include <tuple>
72 #include <utility>
73 #include <vector>
74
75 using namespace clang;
76 using namespace ento;
77 using namespace llvm;
78
79 #define DEBUG_TYPE "BugReporter"
80
81 STATISTIC(MaxBugClassSize,
82 "The maximum number of bug reports in the same equivalence class");
83 STATISTIC(MaxValidBugClassSize,
84 "The maximum number of bug reports in the same equivalence class "
85 "where at least one report is valid (not suppressed)");
86
87 BugReporterVisitor::~BugReporterVisitor() = default;
88
anchor()89 void BugReporterContext::anchor() {}
90
91 //===----------------------------------------------------------------------===//
92 // PathDiagnosticBuilder and its associated routines and helper objects.
93 //===----------------------------------------------------------------------===//
94
95 namespace {
96
97 /// A (CallPiece, node assiciated with its CallEnter) pair.
98 using CallWithEntry =
99 std::pair<PathDiagnosticCallPiece *, const ExplodedNode *>;
100 using CallWithEntryStack = SmallVector<CallWithEntry, 6>;
101
102 /// Map from each node to the diagnostic pieces visitors emit for them.
103 using VisitorsDiagnosticsTy =
104 llvm::DenseMap<const ExplodedNode *, std::vector<PathDiagnosticPieceRef>>;
105
106 /// A map from PathDiagnosticPiece to the LocationContext of the inlined
107 /// function call it represents.
108 using LocationContextMap =
109 llvm::DenseMap<const PathPieces *, const LocationContext *>;
110
111 /// A helper class that contains everything needed to construct a
112 /// PathDiagnostic object. It does no much more then providing convenient
113 /// getters and some well placed asserts for extra security.
114 class PathDiagnosticConstruct {
115 /// The consumer we're constructing the bug report for.
116 const PathDiagnosticConsumer *Consumer;
117 /// Our current position in the bug path, which is owned by
118 /// PathDiagnosticBuilder.
119 const ExplodedNode *CurrentNode;
120 /// A mapping from parts of the bug path (for example, a function call, which
121 /// would span backwards from a CallExit to a CallEnter with the nodes in
122 /// between them) with the location contexts it is associated with.
123 LocationContextMap LCM;
124 const SourceManager &SM;
125
126 public:
127 /// We keep stack of calls to functions as we're ascending the bug path.
128 /// TODO: PathDiagnostic has a stack doing the same thing, shouldn't we use
129 /// that instead?
130 CallWithEntryStack CallStack;
131 /// The bug report we're constructing. For ease of use, this field is kept
132 /// public, though some "shortcut" getters are provided for commonly used
133 /// methods of PathDiagnostic.
134 std::unique_ptr<PathDiagnostic> PD;
135
136 public:
137 PathDiagnosticConstruct(const PathDiagnosticConsumer *PDC,
138 const ExplodedNode *ErrorNode,
139 const PathSensitiveBugReport *R);
140
141 /// \returns the location context associated with the current position in the
142 /// bug path.
getCurrLocationContext() const143 const LocationContext *getCurrLocationContext() const {
144 assert(CurrentNode && "Already reached the root!");
145 return CurrentNode->getLocationContext();
146 }
147
148 /// Same as getCurrLocationContext (they should always return the same
149 /// location context), but works after reaching the root of the bug path as
150 /// well.
getLocationContextForActivePath() const151 const LocationContext *getLocationContextForActivePath() const {
152 return LCM.find(&PD->getActivePath())->getSecond();
153 }
154
getCurrentNode() const155 const ExplodedNode *getCurrentNode() const { return CurrentNode; }
156
157 /// Steps the current node to its predecessor.
158 /// \returns whether we reached the root of the bug path.
ascendToPrevNode()159 bool ascendToPrevNode() {
160 CurrentNode = CurrentNode->getFirstPred();
161 return static_cast<bool>(CurrentNode);
162 }
163
getParentMap() const164 const ParentMap &getParentMap() const {
165 return getCurrLocationContext()->getParentMap();
166 }
167
getSourceManager() const168 const SourceManager &getSourceManager() const { return SM; }
169
getParent(const Stmt * S) const170 const Stmt *getParent(const Stmt *S) const {
171 return getParentMap().getParent(S);
172 }
173
updateLocCtxMap(const PathPieces * Path,const LocationContext * LC)174 void updateLocCtxMap(const PathPieces *Path, const LocationContext *LC) {
175 assert(Path && LC);
176 LCM[Path] = LC;
177 }
178
getLocationContextFor(const PathPieces * Path) const179 const LocationContext *getLocationContextFor(const PathPieces *Path) const {
180 assert(LCM.count(Path) &&
181 "Failed to find the context associated with these pieces!");
182 return LCM.find(Path)->getSecond();
183 }
184
isInLocCtxMap(const PathPieces * Path) const185 bool isInLocCtxMap(const PathPieces *Path) const { return LCM.count(Path); }
186
getActivePath()187 PathPieces &getActivePath() { return PD->getActivePath(); }
getMutablePieces()188 PathPieces &getMutablePieces() { return PD->getMutablePieces(); }
189
shouldAddPathEdges() const190 bool shouldAddPathEdges() const { return Consumer->shouldAddPathEdges(); }
shouldGenerateDiagnostics() const191 bool shouldGenerateDiagnostics() const {
192 return Consumer->shouldGenerateDiagnostics();
193 }
supportsLogicalOpControlFlow() const194 bool supportsLogicalOpControlFlow() const {
195 return Consumer->supportsLogicalOpControlFlow();
196 }
197 };
198
199 /// Contains every contextual information needed for constructing a
200 /// PathDiagnostic object for a given bug report. This class and its fields are
201 /// immutable, and passes a BugReportConstruct object around during the
202 /// construction.
203 class PathDiagnosticBuilder : public BugReporterContext {
204 /// A linear path from the error node to the root.
205 std::unique_ptr<const ExplodedGraph> BugPath;
206 /// The bug report we're describing. Visitors create their diagnostics with
207 /// them being the last entities being able to modify it (for example,
208 /// changing interestingness here would cause inconsistencies as to how this
209 /// file and visitors construct diagnostics), hence its const.
210 const PathSensitiveBugReport *R;
211 /// The leaf of the bug path. This isn't the same as the bug reports error
212 /// node, which refers to the *original* graph, not the bug path.
213 const ExplodedNode *const ErrorNode;
214 /// The diagnostic pieces visitors emitted, which is expected to be collected
215 /// by the time this builder is constructed.
216 std::unique_ptr<const VisitorsDiagnosticsTy> VisitorsDiagnostics;
217
218 public:
219 /// Find a non-invalidated report for a given equivalence class, and returns
220 /// a PathDiagnosticBuilder able to construct bug reports for different
221 /// consumers. Returns None if no valid report is found.
222 static Optional<PathDiagnosticBuilder>
223 findValidReport(ArrayRef<PathSensitiveBugReport *> &bugReports,
224 PathSensitiveBugReporter &Reporter);
225
226 PathDiagnosticBuilder(
227 BugReporterContext BRC, std::unique_ptr<ExplodedGraph> BugPath,
228 PathSensitiveBugReport *r, const ExplodedNode *ErrorNode,
229 std::unique_ptr<VisitorsDiagnosticsTy> VisitorsDiagnostics);
230
231 /// This function is responsible for generating diagnostic pieces that are
232 /// *not* provided by bug report visitors.
233 /// These diagnostics may differ depending on the consumer's settings,
234 /// and are therefore constructed separately for each consumer.
235 ///
236 /// There are two path diagnostics generation modes: with adding edges (used
237 /// for plists) and without (used for HTML and text). When edges are added,
238 /// the path is modified to insert artificially generated edges.
239 /// Otherwise, more detailed diagnostics is emitted for block edges,
240 /// explaining the transitions in words.
241 std::unique_ptr<PathDiagnostic>
242 generate(const PathDiagnosticConsumer *PDC) const;
243
244 private:
245 void updateStackPiecesWithMessage(PathDiagnosticPieceRef P,
246 const CallWithEntryStack &CallStack) const;
247 void generatePathDiagnosticsForNode(PathDiagnosticConstruct &C,
248 PathDiagnosticLocation &PrevLoc) const;
249
250 void generateMinimalDiagForBlockEdge(PathDiagnosticConstruct &C,
251 BlockEdge BE) const;
252
253 PathDiagnosticPieceRef
254 generateDiagForGotoOP(const PathDiagnosticConstruct &C, const Stmt *S,
255 PathDiagnosticLocation &Start) const;
256
257 PathDiagnosticPieceRef
258 generateDiagForSwitchOP(const PathDiagnosticConstruct &C, const CFGBlock *Dst,
259 PathDiagnosticLocation &Start) const;
260
261 PathDiagnosticPieceRef
262 generateDiagForBinaryOP(const PathDiagnosticConstruct &C, const Stmt *T,
263 const CFGBlock *Src, const CFGBlock *DstC) const;
264
265 PathDiagnosticLocation
266 ExecutionContinues(const PathDiagnosticConstruct &C) const;
267
268 PathDiagnosticLocation
269 ExecutionContinues(llvm::raw_string_ostream &os,
270 const PathDiagnosticConstruct &C) const;
271
getBugReport() const272 const PathSensitiveBugReport *getBugReport() const { return R; }
273 };
274
275 } // namespace
276
277 //===----------------------------------------------------------------------===//
278 // Base implementation of stack hint generators.
279 //===----------------------------------------------------------------------===//
280
281 StackHintGenerator::~StackHintGenerator() = default;
282
getMessage(const ExplodedNode * N)283 std::string StackHintGeneratorForSymbol::getMessage(const ExplodedNode *N){
284 if (!N)
285 return getMessageForSymbolNotFound();
286
287 ProgramPoint P = N->getLocation();
288 CallExitEnd CExit = P.castAs<CallExitEnd>();
289
290 // FIXME: Use CallEvent to abstract this over all calls.
291 const Stmt *CallSite = CExit.getCalleeContext()->getCallSite();
292 const auto *CE = dyn_cast_or_null<CallExpr>(CallSite);
293 if (!CE)
294 return {};
295
296 // Check if one of the parameters are set to the interesting symbol.
297 unsigned ArgIndex = 0;
298 for (CallExpr::const_arg_iterator I = CE->arg_begin(),
299 E = CE->arg_end(); I != E; ++I, ++ArgIndex){
300 SVal SV = N->getSVal(*I);
301
302 // Check if the variable corresponding to the symbol is passed by value.
303 SymbolRef AS = SV.getAsLocSymbol();
304 if (AS == Sym) {
305 return getMessageForArg(*I, ArgIndex);
306 }
307
308 // Check if the parameter is a pointer to the symbol.
309 if (Optional<loc::MemRegionVal> Reg = SV.getAs<loc::MemRegionVal>()) {
310 // Do not attempt to dereference void*.
311 if ((*I)->getType()->isVoidPointerType())
312 continue;
313 SVal PSV = N->getState()->getSVal(Reg->getRegion());
314 SymbolRef AS = PSV.getAsLocSymbol();
315 if (AS == Sym) {
316 return getMessageForArg(*I, ArgIndex);
317 }
318 }
319 }
320
321 // Check if we are returning the interesting symbol.
322 SVal SV = N->getSVal(CE);
323 SymbolRef RetSym = SV.getAsLocSymbol();
324 if (RetSym == Sym) {
325 return getMessageForReturn(CE);
326 }
327
328 return getMessageForSymbolNotFound();
329 }
330
getMessageForArg(const Expr * ArgE,unsigned ArgIndex)331 std::string StackHintGeneratorForSymbol::getMessageForArg(const Expr *ArgE,
332 unsigned ArgIndex) {
333 // Printed parameters start at 1, not 0.
334 ++ArgIndex;
335
336 return (llvm::Twine(Msg) + " via " + std::to_string(ArgIndex) +
337 llvm::getOrdinalSuffix(ArgIndex) + " parameter").str();
338 }
339
340 //===----------------------------------------------------------------------===//
341 // Diagnostic cleanup.
342 //===----------------------------------------------------------------------===//
343
344 static PathDiagnosticEventPiece *
eventsDescribeSameCondition(PathDiagnosticEventPiece * X,PathDiagnosticEventPiece * Y)345 eventsDescribeSameCondition(PathDiagnosticEventPiece *X,
346 PathDiagnosticEventPiece *Y) {
347 // Prefer diagnostics that come from ConditionBRVisitor over
348 // those that came from TrackConstraintBRVisitor,
349 // unless the one from ConditionBRVisitor is
350 // its generic fallback diagnostic.
351 const void *tagPreferred = ConditionBRVisitor::getTag();
352 const void *tagLesser = TrackConstraintBRVisitor::getTag();
353
354 if (X->getLocation() != Y->getLocation())
355 return nullptr;
356
357 if (X->getTag() == tagPreferred && Y->getTag() == tagLesser)
358 return ConditionBRVisitor::isPieceMessageGeneric(X) ? Y : X;
359
360 if (Y->getTag() == tagPreferred && X->getTag() == tagLesser)
361 return ConditionBRVisitor::isPieceMessageGeneric(Y) ? X : Y;
362
363 return nullptr;
364 }
365
366 /// An optimization pass over PathPieces that removes redundant diagnostics
367 /// generated by both ConditionBRVisitor and TrackConstraintBRVisitor. Both
368 /// BugReporterVisitors use different methods to generate diagnostics, with
369 /// one capable of emitting diagnostics in some cases but not in others. This
370 /// can lead to redundant diagnostic pieces at the same point in a path.
removeRedundantMsgs(PathPieces & path)371 static void removeRedundantMsgs(PathPieces &path) {
372 unsigned N = path.size();
373 if (N < 2)
374 return;
375 // NOTE: this loop intentionally is not using an iterator. Instead, we
376 // are streaming the path and modifying it in place. This is done by
377 // grabbing the front, processing it, and if we decide to keep it append
378 // it to the end of the path. The entire path is processed in this way.
379 for (unsigned i = 0; i < N; ++i) {
380 auto piece = std::move(path.front());
381 path.pop_front();
382
383 switch (piece->getKind()) {
384 case PathDiagnosticPiece::Call:
385 removeRedundantMsgs(cast<PathDiagnosticCallPiece>(*piece).path);
386 break;
387 case PathDiagnosticPiece::Macro:
388 removeRedundantMsgs(cast<PathDiagnosticMacroPiece>(*piece).subPieces);
389 break;
390 case PathDiagnosticPiece::Event: {
391 if (i == N-1)
392 break;
393
394 if (auto *nextEvent =
395 dyn_cast<PathDiagnosticEventPiece>(path.front().get())) {
396 auto *event = cast<PathDiagnosticEventPiece>(piece.get());
397 // Check to see if we should keep one of the two pieces. If we
398 // come up with a preference, record which piece to keep, and consume
399 // another piece from the path.
400 if (auto *pieceToKeep =
401 eventsDescribeSameCondition(event, nextEvent)) {
402 piece = std::move(pieceToKeep == event ? piece : path.front());
403 path.pop_front();
404 ++i;
405 }
406 }
407 break;
408 }
409 case PathDiagnosticPiece::ControlFlow:
410 case PathDiagnosticPiece::Note:
411 case PathDiagnosticPiece::PopUp:
412 break;
413 }
414 path.push_back(std::move(piece));
415 }
416 }
417
418 /// Recursively scan through a path and prune out calls and macros pieces
419 /// that aren't needed. Return true if afterwards the path contains
420 /// "interesting stuff" which means it shouldn't be pruned from the parent path.
removeUnneededCalls(const PathDiagnosticConstruct & C,PathPieces & pieces,const PathSensitiveBugReport * R,bool IsInteresting=false)421 static bool removeUnneededCalls(const PathDiagnosticConstruct &C,
422 PathPieces &pieces,
423 const PathSensitiveBugReport *R,
424 bool IsInteresting = false) {
425 bool containsSomethingInteresting = IsInteresting;
426 const unsigned N = pieces.size();
427
428 for (unsigned i = 0 ; i < N ; ++i) {
429 // Remove the front piece from the path. If it is still something we
430 // want to keep once we are done, we will push it back on the end.
431 auto piece = std::move(pieces.front());
432 pieces.pop_front();
433
434 switch (piece->getKind()) {
435 case PathDiagnosticPiece::Call: {
436 auto &call = cast<PathDiagnosticCallPiece>(*piece);
437 // Check if the location context is interesting.
438 if (!removeUnneededCalls(
439 C, call.path, R,
440 R->isInteresting(C.getLocationContextFor(&call.path))))
441 continue;
442
443 containsSomethingInteresting = true;
444 break;
445 }
446 case PathDiagnosticPiece::Macro: {
447 auto ¯o = cast<PathDiagnosticMacroPiece>(*piece);
448 if (!removeUnneededCalls(C, macro.subPieces, R, IsInteresting))
449 continue;
450 containsSomethingInteresting = true;
451 break;
452 }
453 case PathDiagnosticPiece::Event: {
454 auto &event = cast<PathDiagnosticEventPiece>(*piece);
455
456 // We never throw away an event, but we do throw it away wholesale
457 // as part of a path if we throw the entire path away.
458 containsSomethingInteresting |= !event.isPrunable();
459 break;
460 }
461 case PathDiagnosticPiece::ControlFlow:
462 case PathDiagnosticPiece::Note:
463 case PathDiagnosticPiece::PopUp:
464 break;
465 }
466
467 pieces.push_back(std::move(piece));
468 }
469
470 return containsSomethingInteresting;
471 }
472
473 /// Same logic as above to remove extra pieces.
removePopUpNotes(PathPieces & Path)474 static void removePopUpNotes(PathPieces &Path) {
475 for (unsigned int i = 0; i < Path.size(); ++i) {
476 auto Piece = std::move(Path.front());
477 Path.pop_front();
478 if (!isa<PathDiagnosticPopUpPiece>(*Piece))
479 Path.push_back(std::move(Piece));
480 }
481 }
482
483 /// Returns true if the given decl has been implicitly given a body, either by
484 /// the analyzer or by the compiler proper.
hasImplicitBody(const Decl * D)485 static bool hasImplicitBody(const Decl *D) {
486 assert(D);
487 return D->isImplicit() || !D->hasBody();
488 }
489
490 /// Recursively scan through a path and make sure that all call pieces have
491 /// valid locations.
492 static void
adjustCallLocations(PathPieces & Pieces,PathDiagnosticLocation * LastCallLocation=nullptr)493 adjustCallLocations(PathPieces &Pieces,
494 PathDiagnosticLocation *LastCallLocation = nullptr) {
495 for (const auto &I : Pieces) {
496 auto *Call = dyn_cast<PathDiagnosticCallPiece>(I.get());
497
498 if (!Call)
499 continue;
500
501 if (LastCallLocation) {
502 bool CallerIsImplicit = hasImplicitBody(Call->getCaller());
503 if (CallerIsImplicit || !Call->callEnter.asLocation().isValid())
504 Call->callEnter = *LastCallLocation;
505 if (CallerIsImplicit || !Call->callReturn.asLocation().isValid())
506 Call->callReturn = *LastCallLocation;
507 }
508
509 // Recursively clean out the subclass. Keep this call around if
510 // it contains any informative diagnostics.
511 PathDiagnosticLocation *ThisCallLocation;
512 if (Call->callEnterWithin.asLocation().isValid() &&
513 !hasImplicitBody(Call->getCallee()))
514 ThisCallLocation = &Call->callEnterWithin;
515 else
516 ThisCallLocation = &Call->callEnter;
517
518 assert(ThisCallLocation && "Outermost call has an invalid location");
519 adjustCallLocations(Call->path, ThisCallLocation);
520 }
521 }
522
523 /// Remove edges in and out of C++ default initializer expressions. These are
524 /// for fields that have in-class initializers, as opposed to being initialized
525 /// explicitly in a constructor or braced list.
removeEdgesToDefaultInitializers(PathPieces & Pieces)526 static void removeEdgesToDefaultInitializers(PathPieces &Pieces) {
527 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) {
528 if (auto *C = dyn_cast<PathDiagnosticCallPiece>(I->get()))
529 removeEdgesToDefaultInitializers(C->path);
530
531 if (auto *M = dyn_cast<PathDiagnosticMacroPiece>(I->get()))
532 removeEdgesToDefaultInitializers(M->subPieces);
533
534 if (auto *CF = dyn_cast<PathDiagnosticControlFlowPiece>(I->get())) {
535 const Stmt *Start = CF->getStartLocation().asStmt();
536 const Stmt *End = CF->getEndLocation().asStmt();
537 if (Start && isa<CXXDefaultInitExpr>(Start)) {
538 I = Pieces.erase(I);
539 continue;
540 } else if (End && isa<CXXDefaultInitExpr>(End)) {
541 PathPieces::iterator Next = std::next(I);
542 if (Next != E) {
543 if (auto *NextCF =
544 dyn_cast<PathDiagnosticControlFlowPiece>(Next->get())) {
545 NextCF->setStartLocation(CF->getStartLocation());
546 }
547 }
548 I = Pieces.erase(I);
549 continue;
550 }
551 }
552
553 I++;
554 }
555 }
556
557 /// Remove all pieces with invalid locations as these cannot be serialized.
558 /// We might have pieces with invalid locations as a result of inlining Body
559 /// Farm generated functions.
removePiecesWithInvalidLocations(PathPieces & Pieces)560 static void removePiecesWithInvalidLocations(PathPieces &Pieces) {
561 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) {
562 if (auto *C = dyn_cast<PathDiagnosticCallPiece>(I->get()))
563 removePiecesWithInvalidLocations(C->path);
564
565 if (auto *M = dyn_cast<PathDiagnosticMacroPiece>(I->get()))
566 removePiecesWithInvalidLocations(M->subPieces);
567
568 if (!(*I)->getLocation().isValid() ||
569 !(*I)->getLocation().asLocation().isValid()) {
570 I = Pieces.erase(I);
571 continue;
572 }
573 I++;
574 }
575 }
576
ExecutionContinues(const PathDiagnosticConstruct & C) const577 PathDiagnosticLocation PathDiagnosticBuilder::ExecutionContinues(
578 const PathDiagnosticConstruct &C) const {
579 if (const Stmt *S = C.getCurrentNode()->getNextStmtForDiagnostics())
580 return PathDiagnosticLocation(S, getSourceManager(),
581 C.getCurrLocationContext());
582
583 return PathDiagnosticLocation::createDeclEnd(C.getCurrLocationContext(),
584 getSourceManager());
585 }
586
ExecutionContinues(llvm::raw_string_ostream & os,const PathDiagnosticConstruct & C) const587 PathDiagnosticLocation PathDiagnosticBuilder::ExecutionContinues(
588 llvm::raw_string_ostream &os, const PathDiagnosticConstruct &C) const {
589 // Slow, but probably doesn't matter.
590 if (os.str().empty())
591 os << ' ';
592
593 const PathDiagnosticLocation &Loc = ExecutionContinues(C);
594
595 if (Loc.asStmt())
596 os << "Execution continues on line "
597 << getSourceManager().getExpansionLineNumber(Loc.asLocation())
598 << '.';
599 else {
600 os << "Execution jumps to the end of the ";
601 const Decl *D = C.getCurrLocationContext()->getDecl();
602 if (isa<ObjCMethodDecl>(D))
603 os << "method";
604 else if (isa<FunctionDecl>(D))
605 os << "function";
606 else {
607 assert(isa<BlockDecl>(D));
608 os << "anonymous block";
609 }
610 os << '.';
611 }
612
613 return Loc;
614 }
615
getEnclosingParent(const Stmt * S,const ParentMap & PM)616 static const Stmt *getEnclosingParent(const Stmt *S, const ParentMap &PM) {
617 if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S)))
618 return PM.getParentIgnoreParens(S);
619
620 const Stmt *Parent = PM.getParentIgnoreParens(S);
621 if (!Parent)
622 return nullptr;
623
624 switch (Parent->getStmtClass()) {
625 case Stmt::ForStmtClass:
626 case Stmt::DoStmtClass:
627 case Stmt::WhileStmtClass:
628 case Stmt::ObjCForCollectionStmtClass:
629 case Stmt::CXXForRangeStmtClass:
630 return Parent;
631 default:
632 break;
633 }
634
635 return nullptr;
636 }
637
638 static PathDiagnosticLocation
getEnclosingStmtLocation(const Stmt * S,const LocationContext * LC,bool allowNestedContexts=false)639 getEnclosingStmtLocation(const Stmt *S, const LocationContext *LC,
640 bool allowNestedContexts = false) {
641 if (!S)
642 return {};
643
644 const SourceManager &SMgr = LC->getDecl()->getASTContext().getSourceManager();
645
646 while (const Stmt *Parent = getEnclosingParent(S, LC->getParentMap())) {
647 switch (Parent->getStmtClass()) {
648 case Stmt::BinaryOperatorClass: {
649 const auto *B = cast<BinaryOperator>(Parent);
650 if (B->isLogicalOp())
651 return PathDiagnosticLocation(allowNestedContexts ? B : S, SMgr, LC);
652 break;
653 }
654 case Stmt::CompoundStmtClass:
655 case Stmt::StmtExprClass:
656 return PathDiagnosticLocation(S, SMgr, LC);
657 case Stmt::ChooseExprClass:
658 // Similar to '?' if we are referring to condition, just have the edge
659 // point to the entire choose expression.
660 if (allowNestedContexts || cast<ChooseExpr>(Parent)->getCond() == S)
661 return PathDiagnosticLocation(Parent, SMgr, LC);
662 else
663 return PathDiagnosticLocation(S, SMgr, LC);
664 case Stmt::BinaryConditionalOperatorClass:
665 case Stmt::ConditionalOperatorClass:
666 // For '?', if we are referring to condition, just have the edge point
667 // to the entire '?' expression.
668 if (allowNestedContexts ||
669 cast<AbstractConditionalOperator>(Parent)->getCond() == S)
670 return PathDiagnosticLocation(Parent, SMgr, LC);
671 else
672 return PathDiagnosticLocation(S, SMgr, LC);
673 case Stmt::CXXForRangeStmtClass:
674 if (cast<CXXForRangeStmt>(Parent)->getBody() == S)
675 return PathDiagnosticLocation(S, SMgr, LC);
676 break;
677 case Stmt::DoStmtClass:
678 return PathDiagnosticLocation(S, SMgr, LC);
679 case Stmt::ForStmtClass:
680 if (cast<ForStmt>(Parent)->getBody() == S)
681 return PathDiagnosticLocation(S, SMgr, LC);
682 break;
683 case Stmt::IfStmtClass:
684 if (cast<IfStmt>(Parent)->getCond() != S)
685 return PathDiagnosticLocation(S, SMgr, LC);
686 break;
687 case Stmt::ObjCForCollectionStmtClass:
688 if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S)
689 return PathDiagnosticLocation(S, SMgr, LC);
690 break;
691 case Stmt::WhileStmtClass:
692 if (cast<WhileStmt>(Parent)->getCond() != S)
693 return PathDiagnosticLocation(S, SMgr, LC);
694 break;
695 default:
696 break;
697 }
698
699 S = Parent;
700 }
701
702 assert(S && "Cannot have null Stmt for PathDiagnosticLocation");
703
704 return PathDiagnosticLocation(S, SMgr, LC);
705 }
706
707 //===----------------------------------------------------------------------===//
708 // "Minimal" path diagnostic generation algorithm.
709 //===----------------------------------------------------------------------===//
710
711 /// If the piece contains a special message, add it to all the call pieces on
712 /// the active stack. For example, my_malloc allocated memory, so MallocChecker
713 /// will construct an event at the call to malloc(), and add a stack hint that
714 /// an allocated memory was returned. We'll use this hint to construct a message
715 /// when returning from the call to my_malloc
716 ///
717 /// void *my_malloc() { return malloc(sizeof(int)); }
718 /// void fishy() {
719 /// void *ptr = my_malloc(); // returned allocated memory
720 /// } // leak
updateStackPiecesWithMessage(PathDiagnosticPieceRef P,const CallWithEntryStack & CallStack) const721 void PathDiagnosticBuilder::updateStackPiecesWithMessage(
722 PathDiagnosticPieceRef P, const CallWithEntryStack &CallStack) const {
723 if (R->hasCallStackHint(P))
724 for (const auto &I : CallStack) {
725 PathDiagnosticCallPiece *CP = I.first;
726 const ExplodedNode *N = I.second;
727 std::string stackMsg = R->getCallStackMessage(P, N);
728
729 // The last message on the path to final bug is the most important
730 // one. Since we traverse the path backwards, do not add the message
731 // if one has been previously added.
732 if (!CP->hasCallStackMessage())
733 CP->setCallStackMessage(stackMsg);
734 }
735 }
736
737 static void CompactMacroExpandedPieces(PathPieces &path,
738 const SourceManager& SM);
739
generateDiagForSwitchOP(const PathDiagnosticConstruct & C,const CFGBlock * Dst,PathDiagnosticLocation & Start) const740 PathDiagnosticPieceRef PathDiagnosticBuilder::generateDiagForSwitchOP(
741 const PathDiagnosticConstruct &C, const CFGBlock *Dst,
742 PathDiagnosticLocation &Start) const {
743
744 const SourceManager &SM = getSourceManager();
745 // Figure out what case arm we took.
746 std::string sbuf;
747 llvm::raw_string_ostream os(sbuf);
748 PathDiagnosticLocation End;
749
750 if (const Stmt *S = Dst->getLabel()) {
751 End = PathDiagnosticLocation(S, SM, C.getCurrLocationContext());
752
753 switch (S->getStmtClass()) {
754 default:
755 os << "No cases match in the switch statement. "
756 "Control jumps to line "
757 << End.asLocation().getExpansionLineNumber();
758 break;
759 case Stmt::DefaultStmtClass:
760 os << "Control jumps to the 'default' case at line "
761 << End.asLocation().getExpansionLineNumber();
762 break;
763
764 case Stmt::CaseStmtClass: {
765 os << "Control jumps to 'case ";
766 const auto *Case = cast<CaseStmt>(S);
767 const Expr *LHS = Case->getLHS()->IgnoreParenCasts();
768
769 // Determine if it is an enum.
770 bool GetRawInt = true;
771
772 if (const auto *DR = dyn_cast<DeclRefExpr>(LHS)) {
773 // FIXME: Maybe this should be an assertion. Are there cases
774 // were it is not an EnumConstantDecl?
775 const auto *D = dyn_cast<EnumConstantDecl>(DR->getDecl());
776
777 if (D) {
778 GetRawInt = false;
779 os << *D;
780 }
781 }
782
783 if (GetRawInt)
784 os << LHS->EvaluateKnownConstInt(getASTContext());
785
786 os << ":' at line " << End.asLocation().getExpansionLineNumber();
787 break;
788 }
789 }
790 } else {
791 os << "'Default' branch taken. ";
792 End = ExecutionContinues(os, C);
793 }
794 return std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
795 os.str());
796 }
797
generateDiagForGotoOP(const PathDiagnosticConstruct & C,const Stmt * S,PathDiagnosticLocation & Start) const798 PathDiagnosticPieceRef PathDiagnosticBuilder::generateDiagForGotoOP(
799 const PathDiagnosticConstruct &C, const Stmt *S,
800 PathDiagnosticLocation &Start) const {
801 std::string sbuf;
802 llvm::raw_string_ostream os(sbuf);
803 const PathDiagnosticLocation &End =
804 getEnclosingStmtLocation(S, C.getCurrLocationContext());
805 os << "Control jumps to line " << End.asLocation().getExpansionLineNumber();
806 return std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str());
807 }
808
generateDiagForBinaryOP(const PathDiagnosticConstruct & C,const Stmt * T,const CFGBlock * Src,const CFGBlock * Dst) const809 PathDiagnosticPieceRef PathDiagnosticBuilder::generateDiagForBinaryOP(
810 const PathDiagnosticConstruct &C, const Stmt *T, const CFGBlock *Src,
811 const CFGBlock *Dst) const {
812
813 const SourceManager &SM = getSourceManager();
814
815 const auto *B = cast<BinaryOperator>(T);
816 std::string sbuf;
817 llvm::raw_string_ostream os(sbuf);
818 os << "Left side of '";
819 PathDiagnosticLocation Start, End;
820
821 if (B->getOpcode() == BO_LAnd) {
822 os << "&&"
823 << "' is ";
824
825 if (*(Src->succ_begin() + 1) == Dst) {
826 os << "false";
827 End = PathDiagnosticLocation(B->getLHS(), SM, C.getCurrLocationContext());
828 Start =
829 PathDiagnosticLocation::createOperatorLoc(B, SM);
830 } else {
831 os << "true";
832 Start =
833 PathDiagnosticLocation(B->getLHS(), SM, C.getCurrLocationContext());
834 End = ExecutionContinues(C);
835 }
836 } else {
837 assert(B->getOpcode() == BO_LOr);
838 os << "||"
839 << "' is ";
840
841 if (*(Src->succ_begin() + 1) == Dst) {
842 os << "false";
843 Start =
844 PathDiagnosticLocation(B->getLHS(), SM, C.getCurrLocationContext());
845 End = ExecutionContinues(C);
846 } else {
847 os << "true";
848 End = PathDiagnosticLocation(B->getLHS(), SM, C.getCurrLocationContext());
849 Start =
850 PathDiagnosticLocation::createOperatorLoc(B, SM);
851 }
852 }
853 return std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
854 os.str());
855 }
856
generateMinimalDiagForBlockEdge(PathDiagnosticConstruct & C,BlockEdge BE) const857 void PathDiagnosticBuilder::generateMinimalDiagForBlockEdge(
858 PathDiagnosticConstruct &C, BlockEdge BE) const {
859 const SourceManager &SM = getSourceManager();
860 const LocationContext *LC = C.getCurrLocationContext();
861 const CFGBlock *Src = BE.getSrc();
862 const CFGBlock *Dst = BE.getDst();
863 const Stmt *T = Src->getTerminatorStmt();
864 if (!T)
865 return;
866
867 auto Start = PathDiagnosticLocation::createBegin(T, SM, LC);
868 switch (T->getStmtClass()) {
869 default:
870 break;
871
872 case Stmt::GotoStmtClass:
873 case Stmt::IndirectGotoStmtClass: {
874 if (const Stmt *S = C.getCurrentNode()->getNextStmtForDiagnostics())
875 C.getActivePath().push_front(generateDiagForGotoOP(C, S, Start));
876 break;
877 }
878
879 case Stmt::SwitchStmtClass: {
880 C.getActivePath().push_front(generateDiagForSwitchOP(C, Dst, Start));
881 break;
882 }
883
884 case Stmt::BreakStmtClass:
885 case Stmt::ContinueStmtClass: {
886 std::string sbuf;
887 llvm::raw_string_ostream os(sbuf);
888 PathDiagnosticLocation End = ExecutionContinues(os, C);
889 C.getActivePath().push_front(
890 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str()));
891 break;
892 }
893
894 // Determine control-flow for ternary '?'.
895 case Stmt::BinaryConditionalOperatorClass:
896 case Stmt::ConditionalOperatorClass: {
897 std::string sbuf;
898 llvm::raw_string_ostream os(sbuf);
899 os << "'?' condition is ";
900
901 if (*(Src->succ_begin() + 1) == Dst)
902 os << "false";
903 else
904 os << "true";
905
906 PathDiagnosticLocation End = ExecutionContinues(C);
907
908 if (const Stmt *S = End.asStmt())
909 End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
910
911 C.getActivePath().push_front(
912 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End, os.str()));
913 break;
914 }
915
916 // Determine control-flow for short-circuited '&&' and '||'.
917 case Stmt::BinaryOperatorClass: {
918 if (!C.supportsLogicalOpControlFlow())
919 break;
920
921 C.getActivePath().push_front(generateDiagForBinaryOP(C, T, Src, Dst));
922 break;
923 }
924
925 case Stmt::DoStmtClass:
926 if (*(Src->succ_begin()) == Dst) {
927 std::string sbuf;
928 llvm::raw_string_ostream os(sbuf);
929
930 os << "Loop condition is true. ";
931 PathDiagnosticLocation End = ExecutionContinues(os, C);
932
933 if (const Stmt *S = End.asStmt())
934 End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
935
936 C.getActivePath().push_front(
937 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
938 os.str()));
939 } else {
940 PathDiagnosticLocation End = ExecutionContinues(C);
941
942 if (const Stmt *S = End.asStmt())
943 End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
944
945 C.getActivePath().push_front(
946 std::make_shared<PathDiagnosticControlFlowPiece>(
947 Start, End, "Loop condition is false. Exiting loop"));
948 }
949 break;
950
951 case Stmt::WhileStmtClass:
952 case Stmt::ForStmtClass:
953 if (*(Src->succ_begin() + 1) == Dst) {
954 std::string sbuf;
955 llvm::raw_string_ostream os(sbuf);
956
957 os << "Loop condition is false. ";
958 PathDiagnosticLocation End = ExecutionContinues(os, C);
959 if (const Stmt *S = End.asStmt())
960 End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
961
962 C.getActivePath().push_front(
963 std::make_shared<PathDiagnosticControlFlowPiece>(Start, End,
964 os.str()));
965 } else {
966 PathDiagnosticLocation End = ExecutionContinues(C);
967 if (const Stmt *S = End.asStmt())
968 End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
969
970 C.getActivePath().push_front(
971 std::make_shared<PathDiagnosticControlFlowPiece>(
972 Start, End, "Loop condition is true. Entering loop body"));
973 }
974
975 break;
976
977 case Stmt::IfStmtClass: {
978 PathDiagnosticLocation End = ExecutionContinues(C);
979
980 if (const Stmt *S = End.asStmt())
981 End = getEnclosingStmtLocation(S, C.getCurrLocationContext());
982
983 if (*(Src->succ_begin() + 1) == Dst)
984 C.getActivePath().push_front(
985 std::make_shared<PathDiagnosticControlFlowPiece>(
986 Start, End, "Taking false branch"));
987 else
988 C.getActivePath().push_front(
989 std::make_shared<PathDiagnosticControlFlowPiece>(
990 Start, End, "Taking true branch"));
991
992 break;
993 }
994 }
995 }
996
997 //===----------------------------------------------------------------------===//
998 // Functions for determining if a loop was executed 0 times.
999 //===----------------------------------------------------------------------===//
1000
isLoop(const Stmt * Term)1001 static bool isLoop(const Stmt *Term) {
1002 switch (Term->getStmtClass()) {
1003 case Stmt::ForStmtClass:
1004 case Stmt::WhileStmtClass:
1005 case Stmt::ObjCForCollectionStmtClass:
1006 case Stmt::CXXForRangeStmtClass:
1007 return true;
1008 default:
1009 // Note that we intentionally do not include do..while here.
1010 return false;
1011 }
1012 }
1013
isJumpToFalseBranch(const BlockEdge * BE)1014 static bool isJumpToFalseBranch(const BlockEdge *BE) {
1015 const CFGBlock *Src = BE->getSrc();
1016 assert(Src->succ_size() == 2);
1017 return (*(Src->succ_begin()+1) == BE->getDst());
1018 }
1019
isContainedByStmt(const ParentMap & PM,const Stmt * S,const Stmt * SubS)1020 static bool isContainedByStmt(const ParentMap &PM, const Stmt *S,
1021 const Stmt *SubS) {
1022 while (SubS) {
1023 if (SubS == S)
1024 return true;
1025 SubS = PM.getParent(SubS);
1026 }
1027 return false;
1028 }
1029
getStmtBeforeCond(const ParentMap & PM,const Stmt * Term,const ExplodedNode * N)1030 static const Stmt *getStmtBeforeCond(const ParentMap &PM, const Stmt *Term,
1031 const ExplodedNode *N) {
1032 while (N) {
1033 Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>();
1034 if (SP) {
1035 const Stmt *S = SP->getStmt();
1036 if (!isContainedByStmt(PM, Term, S))
1037 return S;
1038 }
1039 N = N->getFirstPred();
1040 }
1041 return nullptr;
1042 }
1043
isInLoopBody(const ParentMap & PM,const Stmt * S,const Stmt * Term)1044 static bool isInLoopBody(const ParentMap &PM, const Stmt *S, const Stmt *Term) {
1045 const Stmt *LoopBody = nullptr;
1046 switch (Term->getStmtClass()) {
1047 case Stmt::CXXForRangeStmtClass: {
1048 const auto *FR = cast<CXXForRangeStmt>(Term);
1049 if (isContainedByStmt(PM, FR->getInc(), S))
1050 return true;
1051 if (isContainedByStmt(PM, FR->getLoopVarStmt(), S))
1052 return true;
1053 LoopBody = FR->getBody();
1054 break;
1055 }
1056 case Stmt::ForStmtClass: {
1057 const auto *FS = cast<ForStmt>(Term);
1058 if (isContainedByStmt(PM, FS->getInc(), S))
1059 return true;
1060 LoopBody = FS->getBody();
1061 break;
1062 }
1063 case Stmt::ObjCForCollectionStmtClass: {
1064 const auto *FC = cast<ObjCForCollectionStmt>(Term);
1065 LoopBody = FC->getBody();
1066 break;
1067 }
1068 case Stmt::WhileStmtClass:
1069 LoopBody = cast<WhileStmt>(Term)->getBody();
1070 break;
1071 default:
1072 return false;
1073 }
1074 return isContainedByStmt(PM, LoopBody, S);
1075 }
1076
1077 /// Adds a sanitized control-flow diagnostic edge to a path.
addEdgeToPath(PathPieces & path,PathDiagnosticLocation & PrevLoc,PathDiagnosticLocation NewLoc)1078 static void addEdgeToPath(PathPieces &path,
1079 PathDiagnosticLocation &PrevLoc,
1080 PathDiagnosticLocation NewLoc) {
1081 if (!NewLoc.isValid())
1082 return;
1083
1084 SourceLocation NewLocL = NewLoc.asLocation();
1085 if (NewLocL.isInvalid())
1086 return;
1087
1088 if (!PrevLoc.isValid() || !PrevLoc.asLocation().isValid()) {
1089 PrevLoc = NewLoc;
1090 return;
1091 }
1092
1093 // Ignore self-edges, which occur when there are multiple nodes at the same
1094 // statement.
1095 if (NewLoc.asStmt() && NewLoc.asStmt() == PrevLoc.asStmt())
1096 return;
1097
1098 path.push_front(
1099 std::make_shared<PathDiagnosticControlFlowPiece>(NewLoc, PrevLoc));
1100 PrevLoc = NewLoc;
1101 }
1102
1103 /// A customized wrapper for CFGBlock::getTerminatorCondition()
1104 /// which returns the element for ObjCForCollectionStmts.
getTerminatorCondition(const CFGBlock * B)1105 static const Stmt *getTerminatorCondition(const CFGBlock *B) {
1106 const Stmt *S = B->getTerminatorCondition();
1107 if (const auto *FS = dyn_cast_or_null<ObjCForCollectionStmt>(S))
1108 return FS->getElement();
1109 return S;
1110 }
1111
1112 constexpr llvm::StringLiteral StrEnteringLoop = "Entering loop body";
1113 constexpr llvm::StringLiteral StrLoopBodyZero = "Loop body executed 0 times";
1114 constexpr llvm::StringLiteral StrLoopRangeEmpty =
1115 "Loop body skipped when range is empty";
1116 constexpr llvm::StringLiteral StrLoopCollectionEmpty =
1117 "Loop body skipped when collection is empty";
1118
1119 static std::unique_ptr<FilesToLineNumsMap>
1120 findExecutedLines(const SourceManager &SM, const ExplodedNode *N);
1121
generatePathDiagnosticsForNode(PathDiagnosticConstruct & C,PathDiagnosticLocation & PrevLoc) const1122 void PathDiagnosticBuilder::generatePathDiagnosticsForNode(
1123 PathDiagnosticConstruct &C, PathDiagnosticLocation &PrevLoc) const {
1124 ProgramPoint P = C.getCurrentNode()->getLocation();
1125 const SourceManager &SM = getSourceManager();
1126
1127 // Have we encountered an entrance to a call? It may be
1128 // the case that we have not encountered a matching
1129 // call exit before this point. This means that the path
1130 // terminated within the call itself.
1131 if (auto CE = P.getAs<CallEnter>()) {
1132
1133 if (C.shouldAddPathEdges()) {
1134 // Add an edge to the start of the function.
1135 const StackFrameContext *CalleeLC = CE->getCalleeContext();
1136 const Decl *D = CalleeLC->getDecl();
1137 // Add the edge only when the callee has body. We jump to the beginning
1138 // of the *declaration*, however we expect it to be followed by the
1139 // body. This isn't the case for autosynthesized property accessors in
1140 // Objective-C. No need for a similar extra check for CallExit points
1141 // because the exit edge comes from a statement (i.e. return),
1142 // not from declaration.
1143 if (D->hasBody())
1144 addEdgeToPath(C.getActivePath(), PrevLoc,
1145 PathDiagnosticLocation::createBegin(D, SM));
1146 }
1147
1148 // Did we visit an entire call?
1149 bool VisitedEntireCall = C.PD->isWithinCall();
1150 C.PD->popActivePath();
1151
1152 PathDiagnosticCallPiece *Call;
1153 if (VisitedEntireCall) {
1154 Call = cast<PathDiagnosticCallPiece>(C.getActivePath().front().get());
1155 } else {
1156 // The path terminated within a nested location context, create a new
1157 // call piece to encapsulate the rest of the path pieces.
1158 const Decl *Caller = CE->getLocationContext()->getDecl();
1159 Call = PathDiagnosticCallPiece::construct(C.getActivePath(), Caller);
1160 assert(C.getActivePath().size() == 1 &&
1161 C.getActivePath().front().get() == Call);
1162
1163 // Since we just transferred the path over to the call piece, reset the
1164 // mapping of the active path to the current location context.
1165 assert(C.isInLocCtxMap(&C.getActivePath()) &&
1166 "When we ascend to a previously unvisited call, the active path's "
1167 "address shouldn't change, but rather should be compacted into "
1168 "a single CallEvent!");
1169 C.updateLocCtxMap(&C.getActivePath(), C.getCurrLocationContext());
1170
1171 // Record the location context mapping for the path within the call.
1172 assert(!C.isInLocCtxMap(&Call->path) &&
1173 "When we ascend to a previously unvisited call, this must be the "
1174 "first time we encounter the caller context!");
1175 C.updateLocCtxMap(&Call->path, CE->getCalleeContext());
1176 }
1177 Call->setCallee(*CE, SM);
1178
1179 // Update the previous location in the active path.
1180 PrevLoc = Call->getLocation();
1181
1182 if (!C.CallStack.empty()) {
1183 assert(C.CallStack.back().first == Call);
1184 C.CallStack.pop_back();
1185 }
1186 return;
1187 }
1188
1189 assert(C.getCurrLocationContext() == C.getLocationContextForActivePath() &&
1190 "The current position in the bug path is out of sync with the "
1191 "location context associated with the active path!");
1192
1193 // Have we encountered an exit from a function call?
1194 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) {
1195
1196 // We are descending into a call (backwards). Construct
1197 // a new call piece to contain the path pieces for that call.
1198 auto Call = PathDiagnosticCallPiece::construct(*CE, SM);
1199 // Record the mapping from call piece to LocationContext.
1200 assert(!C.isInLocCtxMap(&Call->path) &&
1201 "We just entered a call, this must've been the first time we "
1202 "encounter its context!");
1203 C.updateLocCtxMap(&Call->path, CE->getCalleeContext());
1204
1205 if (C.shouldAddPathEdges()) {
1206 // Add the edge to the return site.
1207 addEdgeToPath(C.getActivePath(), PrevLoc, Call->callReturn);
1208 PrevLoc.invalidate();
1209 }
1210
1211 auto *P = Call.get();
1212 C.getActivePath().push_front(std::move(Call));
1213
1214 // Make the contents of the call the active path for now.
1215 C.PD->pushActivePath(&P->path);
1216 C.CallStack.push_back(CallWithEntry(P, C.getCurrentNode()));
1217 return;
1218 }
1219
1220 if (auto PS = P.getAs<PostStmt>()) {
1221 if (!C.shouldAddPathEdges())
1222 return;
1223
1224 // Add an edge. If this is an ObjCForCollectionStmt do
1225 // not add an edge here as it appears in the CFG both
1226 // as a terminator and as a terminator condition.
1227 if (!isa<ObjCForCollectionStmt>(PS->getStmt())) {
1228 PathDiagnosticLocation L =
1229 PathDiagnosticLocation(PS->getStmt(), SM, C.getCurrLocationContext());
1230 addEdgeToPath(C.getActivePath(), PrevLoc, L);
1231 }
1232
1233 } else if (auto BE = P.getAs<BlockEdge>()) {
1234
1235 if (!C.shouldAddPathEdges()) {
1236 generateMinimalDiagForBlockEdge(C, *BE);
1237 return;
1238 }
1239
1240 // Are we jumping to the head of a loop? Add a special diagnostic.
1241 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) {
1242 PathDiagnosticLocation L(Loop, SM, C.getCurrLocationContext());
1243 const Stmt *Body = nullptr;
1244
1245 if (const auto *FS = dyn_cast<ForStmt>(Loop))
1246 Body = FS->getBody();
1247 else if (const auto *WS = dyn_cast<WhileStmt>(Loop))
1248 Body = WS->getBody();
1249 else if (const auto *OFS = dyn_cast<ObjCForCollectionStmt>(Loop)) {
1250 Body = OFS->getBody();
1251 } else if (const auto *FRS = dyn_cast<CXXForRangeStmt>(Loop)) {
1252 Body = FRS->getBody();
1253 }
1254 // do-while statements are explicitly excluded here
1255
1256 auto p = std::make_shared<PathDiagnosticEventPiece>(
1257 L, "Looping back to the head "
1258 "of the loop");
1259 p->setPrunable(true);
1260
1261 addEdgeToPath(C.getActivePath(), PrevLoc, p->getLocation());
1262 C.getActivePath().push_front(std::move(p));
1263
1264 if (const auto *CS = dyn_cast_or_null<CompoundStmt>(Body)) {
1265 addEdgeToPath(C.getActivePath(), PrevLoc,
1266 PathDiagnosticLocation::createEndBrace(CS, SM));
1267 }
1268 }
1269
1270 const CFGBlock *BSrc = BE->getSrc();
1271 const ParentMap &PM = C.getParentMap();
1272
1273 if (const Stmt *Term = BSrc->getTerminatorStmt()) {
1274 // Are we jumping past the loop body without ever executing the
1275 // loop (because the condition was false)?
1276 if (isLoop(Term)) {
1277 const Stmt *TermCond = getTerminatorCondition(BSrc);
1278 bool IsInLoopBody = isInLoopBody(
1279 PM, getStmtBeforeCond(PM, TermCond, C.getCurrentNode()), Term);
1280
1281 StringRef str;
1282
1283 if (isJumpToFalseBranch(&*BE)) {
1284 if (!IsInLoopBody) {
1285 if (isa<ObjCForCollectionStmt>(Term)) {
1286 str = StrLoopCollectionEmpty;
1287 } else if (isa<CXXForRangeStmt>(Term)) {
1288 str = StrLoopRangeEmpty;
1289 } else {
1290 str = StrLoopBodyZero;
1291 }
1292 }
1293 } else {
1294 str = StrEnteringLoop;
1295 }
1296
1297 if (!str.empty()) {
1298 PathDiagnosticLocation L(TermCond ? TermCond : Term, SM,
1299 C.getCurrLocationContext());
1300 auto PE = std::make_shared<PathDiagnosticEventPiece>(L, str);
1301 PE->setPrunable(true);
1302 addEdgeToPath(C.getActivePath(), PrevLoc, PE->getLocation());
1303 C.getActivePath().push_front(std::move(PE));
1304 }
1305 } else if (isa<BreakStmt>(Term) || isa<ContinueStmt>(Term) ||
1306 isa<GotoStmt>(Term)) {
1307 PathDiagnosticLocation L(Term, SM, C.getCurrLocationContext());
1308 addEdgeToPath(C.getActivePath(), PrevLoc, L);
1309 }
1310 }
1311 }
1312 }
1313
1314 static std::unique_ptr<PathDiagnostic>
generateDiagnosticForBasicReport(const BasicBugReport * R)1315 generateDiagnosticForBasicReport(const BasicBugReport *R) {
1316 const BugType &BT = R->getBugType();
1317 return std::make_unique<PathDiagnostic>(
1318 BT.getCheckerName(), R->getDeclWithIssue(), BT.getDescription(),
1319 R->getDescription(), R->getShortDescription(/*UseFallback=*/false),
1320 BT.getCategory(), R->getUniqueingLocation(), R->getUniqueingDecl(),
1321 std::make_unique<FilesToLineNumsMap>());
1322 }
1323
1324 static std::unique_ptr<PathDiagnostic>
generateEmptyDiagnosticForReport(const PathSensitiveBugReport * R,const SourceManager & SM)1325 generateEmptyDiagnosticForReport(const PathSensitiveBugReport *R,
1326 const SourceManager &SM) {
1327 const BugType &BT = R->getBugType();
1328 return std::make_unique<PathDiagnostic>(
1329 BT.getCheckerName(), R->getDeclWithIssue(), BT.getDescription(),
1330 R->getDescription(), R->getShortDescription(/*UseFallback=*/false),
1331 BT.getCategory(), R->getUniqueingLocation(), R->getUniqueingDecl(),
1332 findExecutedLines(SM, R->getErrorNode()));
1333 }
1334
getStmtParent(const Stmt * S,const ParentMap & PM)1335 static const Stmt *getStmtParent(const Stmt *S, const ParentMap &PM) {
1336 if (!S)
1337 return nullptr;
1338
1339 while (true) {
1340 S = PM.getParentIgnoreParens(S);
1341
1342 if (!S)
1343 break;
1344
1345 if (isa<FullExpr>(S) ||
1346 isa<CXXBindTemporaryExpr>(S) ||
1347 isa<SubstNonTypeTemplateParmExpr>(S))
1348 continue;
1349
1350 break;
1351 }
1352
1353 return S;
1354 }
1355
isConditionForTerminator(const Stmt * S,const Stmt * Cond)1356 static bool isConditionForTerminator(const Stmt *S, const Stmt *Cond) {
1357 switch (S->getStmtClass()) {
1358 case Stmt::BinaryOperatorClass: {
1359 const auto *BO = cast<BinaryOperator>(S);
1360 if (!BO->isLogicalOp())
1361 return false;
1362 return BO->getLHS() == Cond || BO->getRHS() == Cond;
1363 }
1364 case Stmt::IfStmtClass:
1365 return cast<IfStmt>(S)->getCond() == Cond;
1366 case Stmt::ForStmtClass:
1367 return cast<ForStmt>(S)->getCond() == Cond;
1368 case Stmt::WhileStmtClass:
1369 return cast<WhileStmt>(S)->getCond() == Cond;
1370 case Stmt::DoStmtClass:
1371 return cast<DoStmt>(S)->getCond() == Cond;
1372 case Stmt::ChooseExprClass:
1373 return cast<ChooseExpr>(S)->getCond() == Cond;
1374 case Stmt::IndirectGotoStmtClass:
1375 return cast<IndirectGotoStmt>(S)->getTarget() == Cond;
1376 case Stmt::SwitchStmtClass:
1377 return cast<SwitchStmt>(S)->getCond() == Cond;
1378 case Stmt::BinaryConditionalOperatorClass:
1379 return cast<BinaryConditionalOperator>(S)->getCond() == Cond;
1380 case Stmt::ConditionalOperatorClass: {
1381 const auto *CO = cast<ConditionalOperator>(S);
1382 return CO->getCond() == Cond ||
1383 CO->getLHS() == Cond ||
1384 CO->getRHS() == Cond;
1385 }
1386 case Stmt::ObjCForCollectionStmtClass:
1387 return cast<ObjCForCollectionStmt>(S)->getElement() == Cond;
1388 case Stmt::CXXForRangeStmtClass: {
1389 const auto *FRS = cast<CXXForRangeStmt>(S);
1390 return FRS->getCond() == Cond || FRS->getRangeInit() == Cond;
1391 }
1392 default:
1393 return false;
1394 }
1395 }
1396
isIncrementOrInitInForLoop(const Stmt * S,const Stmt * FL)1397 static bool isIncrementOrInitInForLoop(const Stmt *S, const Stmt *FL) {
1398 if (const auto *FS = dyn_cast<ForStmt>(FL))
1399 return FS->getInc() == S || FS->getInit() == S;
1400 if (const auto *FRS = dyn_cast<CXXForRangeStmt>(FL))
1401 return FRS->getInc() == S || FRS->getRangeStmt() == S ||
1402 FRS->getLoopVarStmt() || FRS->getRangeInit() == S;
1403 return false;
1404 }
1405
1406 using OptimizedCallsSet = llvm::DenseSet<const PathDiagnosticCallPiece *>;
1407
1408 /// Adds synthetic edges from top-level statements to their subexpressions.
1409 ///
1410 /// This avoids a "swoosh" effect, where an edge from a top-level statement A
1411 /// points to a sub-expression B.1 that's not at the start of B. In these cases,
1412 /// we'd like to see an edge from A to B, then another one from B to B.1.
addContextEdges(PathPieces & pieces,const LocationContext * LC)1413 static void addContextEdges(PathPieces &pieces, const LocationContext *LC) {
1414 const ParentMap &PM = LC->getParentMap();
1415 PathPieces::iterator Prev = pieces.end();
1416 for (PathPieces::iterator I = pieces.begin(), E = Prev; I != E;
1417 Prev = I, ++I) {
1418 auto *Piece = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
1419
1420 if (!Piece)
1421 continue;
1422
1423 PathDiagnosticLocation SrcLoc = Piece->getStartLocation();
1424 SmallVector<PathDiagnosticLocation, 4> SrcContexts;
1425
1426 PathDiagnosticLocation NextSrcContext = SrcLoc;
1427 const Stmt *InnerStmt = nullptr;
1428 while (NextSrcContext.isValid() && NextSrcContext.asStmt() != InnerStmt) {
1429 SrcContexts.push_back(NextSrcContext);
1430 InnerStmt = NextSrcContext.asStmt();
1431 NextSrcContext = getEnclosingStmtLocation(InnerStmt, LC,
1432 /*allowNested=*/true);
1433 }
1434
1435 // Repeatedly split the edge as necessary.
1436 // This is important for nested logical expressions (||, &&, ?:) where we
1437 // want to show all the levels of context.
1438 while (true) {
1439 const Stmt *Dst = Piece->getEndLocation().getStmtOrNull();
1440
1441 // We are looking at an edge. Is the destination within a larger
1442 // expression?
1443 PathDiagnosticLocation DstContext =
1444 getEnclosingStmtLocation(Dst, LC, /*allowNested=*/true);
1445 if (!DstContext.isValid() || DstContext.asStmt() == Dst)
1446 break;
1447
1448 // If the source is in the same context, we're already good.
1449 if (llvm::find(SrcContexts, DstContext) != SrcContexts.end())
1450 break;
1451
1452 // Update the subexpression node to point to the context edge.
1453 Piece->setStartLocation(DstContext);
1454
1455 // Try to extend the previous edge if it's at the same level as the source
1456 // context.
1457 if (Prev != E) {
1458 auto *PrevPiece = dyn_cast<PathDiagnosticControlFlowPiece>(Prev->get());
1459
1460 if (PrevPiece) {
1461 if (const Stmt *PrevSrc =
1462 PrevPiece->getStartLocation().getStmtOrNull()) {
1463 const Stmt *PrevSrcParent = getStmtParent(PrevSrc, PM);
1464 if (PrevSrcParent ==
1465 getStmtParent(DstContext.getStmtOrNull(), PM)) {
1466 PrevPiece->setEndLocation(DstContext);
1467 break;
1468 }
1469 }
1470 }
1471 }
1472
1473 // Otherwise, split the current edge into a context edge and a
1474 // subexpression edge. Note that the context statement may itself have
1475 // context.
1476 auto P =
1477 std::make_shared<PathDiagnosticControlFlowPiece>(SrcLoc, DstContext);
1478 Piece = P.get();
1479 I = pieces.insert(I, std::move(P));
1480 }
1481 }
1482 }
1483
1484 /// Move edges from a branch condition to a branch target
1485 /// when the condition is simple.
1486 ///
1487 /// This restructures some of the work of addContextEdges. That function
1488 /// creates edges this may destroy, but they work together to create a more
1489 /// aesthetically set of edges around branches. After the call to
1490 /// addContextEdges, we may have (1) an edge to the branch, (2) an edge from
1491 /// the branch to the branch condition, and (3) an edge from the branch
1492 /// condition to the branch target. We keep (1), but may wish to remove (2)
1493 /// and move the source of (3) to the branch if the branch condition is simple.
simplifySimpleBranches(PathPieces & pieces)1494 static void simplifySimpleBranches(PathPieces &pieces) {
1495 for (PathPieces::iterator I = pieces.begin(), E = pieces.end(); I != E; ++I) {
1496 const auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
1497
1498 if (!PieceI)
1499 continue;
1500
1501 const Stmt *s1Start = PieceI->getStartLocation().getStmtOrNull();
1502 const Stmt *s1End = PieceI->getEndLocation().getStmtOrNull();
1503
1504 if (!s1Start || !s1End)
1505 continue;
1506
1507 PathPieces::iterator NextI = I; ++NextI;
1508 if (NextI == E)
1509 break;
1510
1511 PathDiagnosticControlFlowPiece *PieceNextI = nullptr;
1512
1513 while (true) {
1514 if (NextI == E)
1515 break;
1516
1517 const auto *EV = dyn_cast<PathDiagnosticEventPiece>(NextI->get());
1518 if (EV) {
1519 StringRef S = EV->getString();
1520 if (S == StrEnteringLoop || S == StrLoopBodyZero ||
1521 S == StrLoopCollectionEmpty || S == StrLoopRangeEmpty) {
1522 ++NextI;
1523 continue;
1524 }
1525 break;
1526 }
1527
1528 PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
1529 break;
1530 }
1531
1532 if (!PieceNextI)
1533 continue;
1534
1535 const Stmt *s2Start = PieceNextI->getStartLocation().getStmtOrNull();
1536 const Stmt *s2End = PieceNextI->getEndLocation().getStmtOrNull();
1537
1538 if (!s2Start || !s2End || s1End != s2Start)
1539 continue;
1540
1541 // We only perform this transformation for specific branch kinds.
1542 // We don't want to do this for do..while, for example.
1543 if (!(isa<ForStmt>(s1Start) || isa<WhileStmt>(s1Start) ||
1544 isa<IfStmt>(s1Start) || isa<ObjCForCollectionStmt>(s1Start) ||
1545 isa<CXXForRangeStmt>(s1Start)))
1546 continue;
1547
1548 // Is s1End the branch condition?
1549 if (!isConditionForTerminator(s1Start, s1End))
1550 continue;
1551
1552 // Perform the hoisting by eliminating (2) and changing the start
1553 // location of (3).
1554 PieceNextI->setStartLocation(PieceI->getStartLocation());
1555 I = pieces.erase(I);
1556 }
1557 }
1558
1559 /// Returns the number of bytes in the given (character-based) SourceRange.
1560 ///
1561 /// If the locations in the range are not on the same line, returns None.
1562 ///
1563 /// Note that this does not do a precise user-visible character or column count.
getLengthOnSingleLine(const SourceManager & SM,SourceRange Range)1564 static Optional<size_t> getLengthOnSingleLine(const SourceManager &SM,
1565 SourceRange Range) {
1566 SourceRange ExpansionRange(SM.getExpansionLoc(Range.getBegin()),
1567 SM.getExpansionRange(Range.getEnd()).getEnd());
1568
1569 FileID FID = SM.getFileID(ExpansionRange.getBegin());
1570 if (FID != SM.getFileID(ExpansionRange.getEnd()))
1571 return None;
1572
1573 Optional<MemoryBufferRef> Buffer = SM.getBufferOrNone(FID);
1574 if (!Buffer)
1575 return None;
1576
1577 unsigned BeginOffset = SM.getFileOffset(ExpansionRange.getBegin());
1578 unsigned EndOffset = SM.getFileOffset(ExpansionRange.getEnd());
1579 StringRef Snippet = Buffer->getBuffer().slice(BeginOffset, EndOffset);
1580
1581 // We're searching the raw bytes of the buffer here, which might include
1582 // escaped newlines and such. That's okay; we're trying to decide whether the
1583 // SourceRange is covering a large or small amount of space in the user's
1584 // editor.
1585 if (Snippet.find_first_of("\r\n") != StringRef::npos)
1586 return None;
1587
1588 // This isn't Unicode-aware, but it doesn't need to be.
1589 return Snippet.size();
1590 }
1591
1592 /// \sa getLengthOnSingleLine(SourceManager, SourceRange)
getLengthOnSingleLine(const SourceManager & SM,const Stmt * S)1593 static Optional<size_t> getLengthOnSingleLine(const SourceManager &SM,
1594 const Stmt *S) {
1595 return getLengthOnSingleLine(SM, S->getSourceRange());
1596 }
1597
1598 /// Eliminate two-edge cycles created by addContextEdges().
1599 ///
1600 /// Once all the context edges are in place, there are plenty of cases where
1601 /// there's a single edge from a top-level statement to a subexpression,
1602 /// followed by a single path note, and then a reverse edge to get back out to
1603 /// the top level. If the statement is simple enough, the subexpression edges
1604 /// just add noise and make it harder to understand what's going on.
1605 ///
1606 /// This function only removes edges in pairs, because removing only one edge
1607 /// might leave other edges dangling.
1608 ///
1609 /// This will not remove edges in more complicated situations:
1610 /// - if there is more than one "hop" leading to or from a subexpression.
1611 /// - if there is an inlined call between the edges instead of a single event.
1612 /// - if the whole statement is large enough that having subexpression arrows
1613 /// might be helpful.
removeContextCycles(PathPieces & Path,const SourceManager & SM)1614 static void removeContextCycles(PathPieces &Path, const SourceManager &SM) {
1615 for (PathPieces::iterator I = Path.begin(), E = Path.end(); I != E; ) {
1616 // Pattern match the current piece and its successor.
1617 const auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
1618
1619 if (!PieceI) {
1620 ++I;
1621 continue;
1622 }
1623
1624 const Stmt *s1Start = PieceI->getStartLocation().getStmtOrNull();
1625 const Stmt *s1End = PieceI->getEndLocation().getStmtOrNull();
1626
1627 PathPieces::iterator NextI = I; ++NextI;
1628 if (NextI == E)
1629 break;
1630
1631 const auto *PieceNextI =
1632 dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
1633
1634 if (!PieceNextI) {
1635 if (isa<PathDiagnosticEventPiece>(NextI->get())) {
1636 ++NextI;
1637 if (NextI == E)
1638 break;
1639 PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
1640 }
1641
1642 if (!PieceNextI) {
1643 ++I;
1644 continue;
1645 }
1646 }
1647
1648 const Stmt *s2Start = PieceNextI->getStartLocation().getStmtOrNull();
1649 const Stmt *s2End = PieceNextI->getEndLocation().getStmtOrNull();
1650
1651 if (s1Start && s2Start && s1Start == s2End && s2Start == s1End) {
1652 const size_t MAX_SHORT_LINE_LENGTH = 80;
1653 Optional<size_t> s1Length = getLengthOnSingleLine(SM, s1Start);
1654 if (s1Length && *s1Length <= MAX_SHORT_LINE_LENGTH) {
1655 Optional<size_t> s2Length = getLengthOnSingleLine(SM, s2Start);
1656 if (s2Length && *s2Length <= MAX_SHORT_LINE_LENGTH) {
1657 Path.erase(I);
1658 I = Path.erase(NextI);
1659 continue;
1660 }
1661 }
1662 }
1663
1664 ++I;
1665 }
1666 }
1667
1668 /// Return true if X is contained by Y.
lexicalContains(const ParentMap & PM,const Stmt * X,const Stmt * Y)1669 static bool lexicalContains(const ParentMap &PM, const Stmt *X, const Stmt *Y) {
1670 while (X) {
1671 if (X == Y)
1672 return true;
1673 X = PM.getParent(X);
1674 }
1675 return false;
1676 }
1677
1678 // Remove short edges on the same line less than 3 columns in difference.
removePunyEdges(PathPieces & path,const SourceManager & SM,const ParentMap & PM)1679 static void removePunyEdges(PathPieces &path, const SourceManager &SM,
1680 const ParentMap &PM) {
1681 bool erased = false;
1682
1683 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E;
1684 erased ? I : ++I) {
1685 erased = false;
1686
1687 const auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
1688
1689 if (!PieceI)
1690 continue;
1691
1692 const Stmt *start = PieceI->getStartLocation().getStmtOrNull();
1693 const Stmt *end = PieceI->getEndLocation().getStmtOrNull();
1694
1695 if (!start || !end)
1696 continue;
1697
1698 const Stmt *endParent = PM.getParent(end);
1699 if (!endParent)
1700 continue;
1701
1702 if (isConditionForTerminator(end, endParent))
1703 continue;
1704
1705 SourceLocation FirstLoc = start->getBeginLoc();
1706 SourceLocation SecondLoc = end->getBeginLoc();
1707
1708 if (!SM.isWrittenInSameFile(FirstLoc, SecondLoc))
1709 continue;
1710 if (SM.isBeforeInTranslationUnit(SecondLoc, FirstLoc))
1711 std::swap(SecondLoc, FirstLoc);
1712
1713 SourceRange EdgeRange(FirstLoc, SecondLoc);
1714 Optional<size_t> ByteWidth = getLengthOnSingleLine(SM, EdgeRange);
1715
1716 // If the statements are on different lines, continue.
1717 if (!ByteWidth)
1718 continue;
1719
1720 const size_t MAX_PUNY_EDGE_LENGTH = 2;
1721 if (*ByteWidth <= MAX_PUNY_EDGE_LENGTH) {
1722 // FIXME: There are enough /bytes/ between the endpoints of the edge, but
1723 // there might not be enough /columns/. A proper user-visible column count
1724 // is probably too expensive, though.
1725 I = path.erase(I);
1726 erased = true;
1727 continue;
1728 }
1729 }
1730 }
1731
removeIdenticalEvents(PathPieces & path)1732 static void removeIdenticalEvents(PathPieces &path) {
1733 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ++I) {
1734 const auto *PieceI = dyn_cast<PathDiagnosticEventPiece>(I->get());
1735
1736 if (!PieceI)
1737 continue;
1738
1739 PathPieces::iterator NextI = I; ++NextI;
1740 if (NextI == E)
1741 return;
1742
1743 const auto *PieceNextI = dyn_cast<PathDiagnosticEventPiece>(NextI->get());
1744
1745 if (!PieceNextI)
1746 continue;
1747
1748 // Erase the second piece if it has the same exact message text.
1749 if (PieceI->getString() == PieceNextI->getString()) {
1750 path.erase(NextI);
1751 }
1752 }
1753 }
1754
optimizeEdges(const PathDiagnosticConstruct & C,PathPieces & path,OptimizedCallsSet & OCS)1755 static bool optimizeEdges(const PathDiagnosticConstruct &C, PathPieces &path,
1756 OptimizedCallsSet &OCS) {
1757 bool hasChanges = false;
1758 const LocationContext *LC = C.getLocationContextFor(&path);
1759 assert(LC);
1760 const ParentMap &PM = LC->getParentMap();
1761 const SourceManager &SM = C.getSourceManager();
1762
1763 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ) {
1764 // Optimize subpaths.
1765 if (auto *CallI = dyn_cast<PathDiagnosticCallPiece>(I->get())) {
1766 // Record the fact that a call has been optimized so we only do the
1767 // effort once.
1768 if (!OCS.count(CallI)) {
1769 while (optimizeEdges(C, CallI->path, OCS)) {
1770 }
1771 OCS.insert(CallI);
1772 }
1773 ++I;
1774 continue;
1775 }
1776
1777 // Pattern match the current piece and its successor.
1778 auto *PieceI = dyn_cast<PathDiagnosticControlFlowPiece>(I->get());
1779
1780 if (!PieceI) {
1781 ++I;
1782 continue;
1783 }
1784
1785 const Stmt *s1Start = PieceI->getStartLocation().getStmtOrNull();
1786 const Stmt *s1End = PieceI->getEndLocation().getStmtOrNull();
1787 const Stmt *level1 = getStmtParent(s1Start, PM);
1788 const Stmt *level2 = getStmtParent(s1End, PM);
1789
1790 PathPieces::iterator NextI = I; ++NextI;
1791 if (NextI == E)
1792 break;
1793
1794 const auto *PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(NextI->get());
1795
1796 if (!PieceNextI) {
1797 ++I;
1798 continue;
1799 }
1800
1801 const Stmt *s2Start = PieceNextI->getStartLocation().getStmtOrNull();
1802 const Stmt *s2End = PieceNextI->getEndLocation().getStmtOrNull();
1803 const Stmt *level3 = getStmtParent(s2Start, PM);
1804 const Stmt *level4 = getStmtParent(s2End, PM);
1805
1806 // Rule I.
1807 //
1808 // If we have two consecutive control edges whose end/begin locations
1809 // are at the same level (e.g. statements or top-level expressions within
1810 // a compound statement, or siblings share a single ancestor expression),
1811 // then merge them if they have no interesting intermediate event.
1812 //
1813 // For example:
1814 //
1815 // (1.1 -> 1.2) -> (1.2 -> 1.3) becomes (1.1 -> 1.3) because the common
1816 // parent is '1'. Here 'x.y.z' represents the hierarchy of statements.
1817 //
1818 // NOTE: this will be limited later in cases where we add barriers
1819 // to prevent this optimization.
1820 if (level1 && level1 == level2 && level1 == level3 && level1 == level4) {
1821 PieceI->setEndLocation(PieceNextI->getEndLocation());
1822 path.erase(NextI);
1823 hasChanges = true;
1824 continue;
1825 }
1826
1827 // Rule II.
1828 //
1829 // Eliminate edges between subexpressions and parent expressions
1830 // when the subexpression is consumed.
1831 //
1832 // NOTE: this will be limited later in cases where we add barriers
1833 // to prevent this optimization.
1834 if (s1End && s1End == s2Start && level2) {
1835 bool removeEdge = false;
1836 // Remove edges into the increment or initialization of a
1837 // loop that have no interleaving event. This means that
1838 // they aren't interesting.
1839 if (isIncrementOrInitInForLoop(s1End, level2))
1840 removeEdge = true;
1841 // Next only consider edges that are not anchored on
1842 // the condition of a terminator. This are intermediate edges
1843 // that we might want to trim.
1844 else if (!isConditionForTerminator(level2, s1End)) {
1845 // Trim edges on expressions that are consumed by
1846 // the parent expression.
1847 if (isa<Expr>(s1End) && PM.isConsumedExpr(cast<Expr>(s1End))) {
1848 removeEdge = true;
1849 }
1850 // Trim edges where a lexical containment doesn't exist.
1851 // For example:
1852 //
1853 // X -> Y -> Z
1854 //
1855 // If 'Z' lexically contains Y (it is an ancestor) and
1856 // 'X' does not lexically contain Y (it is a descendant OR
1857 // it has no lexical relationship at all) then trim.
1858 //
1859 // This can eliminate edges where we dive into a subexpression
1860 // and then pop back out, etc.
1861 else if (s1Start && s2End &&
1862 lexicalContains(PM, s2Start, s2End) &&
1863 !lexicalContains(PM, s1End, s1Start)) {
1864 removeEdge = true;
1865 }
1866 // Trim edges from a subexpression back to the top level if the
1867 // subexpression is on a different line.
1868 //
1869 // A.1 -> A -> B
1870 // becomes
1871 // A.1 -> B
1872 //
1873 // These edges just look ugly and don't usually add anything.
1874 else if (s1Start && s2End &&
1875 lexicalContains(PM, s1Start, s1End)) {
1876 SourceRange EdgeRange(PieceI->getEndLocation().asLocation(),
1877 PieceI->getStartLocation().asLocation());
1878 if (!getLengthOnSingleLine(SM, EdgeRange).hasValue())
1879 removeEdge = true;
1880 }
1881 }
1882
1883 if (removeEdge) {
1884 PieceI->setEndLocation(PieceNextI->getEndLocation());
1885 path.erase(NextI);
1886 hasChanges = true;
1887 continue;
1888 }
1889 }
1890
1891 // Optimize edges for ObjC fast-enumeration loops.
1892 //
1893 // (X -> collection) -> (collection -> element)
1894 //
1895 // becomes:
1896 //
1897 // (X -> element)
1898 if (s1End == s2Start) {
1899 const auto *FS = dyn_cast_or_null<ObjCForCollectionStmt>(level3);
1900 if (FS && FS->getCollection()->IgnoreParens() == s2Start &&
1901 s2End == FS->getElement()) {
1902 PieceI->setEndLocation(PieceNextI->getEndLocation());
1903 path.erase(NextI);
1904 hasChanges = true;
1905 continue;
1906 }
1907 }
1908
1909 // No changes at this index? Move to the next one.
1910 ++I;
1911 }
1912
1913 if (!hasChanges) {
1914 // Adjust edges into subexpressions to make them more uniform
1915 // and aesthetically pleasing.
1916 addContextEdges(path, LC);
1917 // Remove "cyclical" edges that include one or more context edges.
1918 removeContextCycles(path, SM);
1919 // Hoist edges originating from branch conditions to branches
1920 // for simple branches.
1921 simplifySimpleBranches(path);
1922 // Remove any puny edges left over after primary optimization pass.
1923 removePunyEdges(path, SM, PM);
1924 // Remove identical events.
1925 removeIdenticalEvents(path);
1926 }
1927
1928 return hasChanges;
1929 }
1930
1931 /// Drop the very first edge in a path, which should be a function entry edge.
1932 ///
1933 /// If the first edge is not a function entry edge (say, because the first
1934 /// statement had an invalid source location), this function does nothing.
1935 // FIXME: We should just generate invalid edges anyway and have the optimizer
1936 // deal with them.
dropFunctionEntryEdge(const PathDiagnosticConstruct & C,PathPieces & Path)1937 static void dropFunctionEntryEdge(const PathDiagnosticConstruct &C,
1938 PathPieces &Path) {
1939 const auto *FirstEdge =
1940 dyn_cast<PathDiagnosticControlFlowPiece>(Path.front().get());
1941 if (!FirstEdge)
1942 return;
1943
1944 const Decl *D = C.getLocationContextFor(&Path)->getDecl();
1945 PathDiagnosticLocation EntryLoc =
1946 PathDiagnosticLocation::createBegin(D, C.getSourceManager());
1947 if (FirstEdge->getStartLocation() != EntryLoc)
1948 return;
1949
1950 Path.pop_front();
1951 }
1952
1953 /// Populate executes lines with lines containing at least one diagnostics.
updateExecutedLinesWithDiagnosticPieces(PathDiagnostic & PD)1954 static void updateExecutedLinesWithDiagnosticPieces(PathDiagnostic &PD) {
1955
1956 PathPieces path = PD.path.flatten(/*ShouldFlattenMacros=*/true);
1957 FilesToLineNumsMap &ExecutedLines = PD.getExecutedLines();
1958
1959 for (const auto &P : path) {
1960 FullSourceLoc Loc = P->getLocation().asLocation().getExpansionLoc();
1961 FileID FID = Loc.getFileID();
1962 unsigned LineNo = Loc.getLineNumber();
1963 assert(FID.isValid());
1964 ExecutedLines[FID].insert(LineNo);
1965 }
1966 }
1967
PathDiagnosticConstruct(const PathDiagnosticConsumer * PDC,const ExplodedNode * ErrorNode,const PathSensitiveBugReport * R)1968 PathDiagnosticConstruct::PathDiagnosticConstruct(
1969 const PathDiagnosticConsumer *PDC, const ExplodedNode *ErrorNode,
1970 const PathSensitiveBugReport *R)
1971 : Consumer(PDC), CurrentNode(ErrorNode),
1972 SM(CurrentNode->getCodeDecl().getASTContext().getSourceManager()),
1973 PD(generateEmptyDiagnosticForReport(R, getSourceManager())) {
1974 LCM[&PD->getActivePath()] = ErrorNode->getLocationContext();
1975 }
1976
PathDiagnosticBuilder(BugReporterContext BRC,std::unique_ptr<ExplodedGraph> BugPath,PathSensitiveBugReport * r,const ExplodedNode * ErrorNode,std::unique_ptr<VisitorsDiagnosticsTy> VisitorsDiagnostics)1977 PathDiagnosticBuilder::PathDiagnosticBuilder(
1978 BugReporterContext BRC, std::unique_ptr<ExplodedGraph> BugPath,
1979 PathSensitiveBugReport *r, const ExplodedNode *ErrorNode,
1980 std::unique_ptr<VisitorsDiagnosticsTy> VisitorsDiagnostics)
1981 : BugReporterContext(BRC), BugPath(std::move(BugPath)), R(r),
1982 ErrorNode(ErrorNode),
1983 VisitorsDiagnostics(std::move(VisitorsDiagnostics)) {}
1984
1985 std::unique_ptr<PathDiagnostic>
generate(const PathDiagnosticConsumer * PDC) const1986 PathDiagnosticBuilder::generate(const PathDiagnosticConsumer *PDC) const {
1987 PathDiagnosticConstruct Construct(PDC, ErrorNode, R);
1988
1989 const SourceManager &SM = getSourceManager();
1990 const AnalyzerOptions &Opts = getAnalyzerOptions();
1991 StringRef ErrorTag = ErrorNode->getLocation().getTag()->getTagDescription();
1992
1993 // See whether we need to silence the checker/package.
1994 // FIXME: This will not work if the report was emitted with an incorrect tag.
1995 for (const std::string &CheckerOrPackage : Opts.SilencedCheckersAndPackages) {
1996 if (ErrorTag.startswith(CheckerOrPackage))
1997 return nullptr;
1998 }
1999
2000 if (!PDC->shouldGenerateDiagnostics())
2001 return generateEmptyDiagnosticForReport(R, getSourceManager());
2002
2003 // Construct the final (warning) event for the bug report.
2004 auto EndNotes = VisitorsDiagnostics->find(ErrorNode);
2005 PathDiagnosticPieceRef LastPiece;
2006 if (EndNotes != VisitorsDiagnostics->end()) {
2007 assert(!EndNotes->second.empty());
2008 LastPiece = EndNotes->second[0];
2009 } else {
2010 LastPiece = BugReporterVisitor::getDefaultEndPath(*this, ErrorNode,
2011 *getBugReport());
2012 }
2013 Construct.PD->setEndOfPath(LastPiece);
2014
2015 PathDiagnosticLocation PrevLoc = Construct.PD->getLocation();
2016 // From the error node to the root, ascend the bug path and construct the bug
2017 // report.
2018 while (Construct.ascendToPrevNode()) {
2019 generatePathDiagnosticsForNode(Construct, PrevLoc);
2020
2021 auto VisitorNotes = VisitorsDiagnostics->find(Construct.getCurrentNode());
2022 if (VisitorNotes == VisitorsDiagnostics->end())
2023 continue;
2024
2025 // This is a workaround due to inability to put shared PathDiagnosticPiece
2026 // into a FoldingSet.
2027 std::set<llvm::FoldingSetNodeID> DeduplicationSet;
2028
2029 // Add pieces from custom visitors.
2030 for (const PathDiagnosticPieceRef &Note : VisitorNotes->second) {
2031 llvm::FoldingSetNodeID ID;
2032 Note->Profile(ID);
2033 if (!DeduplicationSet.insert(ID).second)
2034 continue;
2035
2036 if (PDC->shouldAddPathEdges())
2037 addEdgeToPath(Construct.getActivePath(), PrevLoc, Note->getLocation());
2038 updateStackPiecesWithMessage(Note, Construct.CallStack);
2039 Construct.getActivePath().push_front(Note);
2040 }
2041 }
2042
2043 if (PDC->shouldAddPathEdges()) {
2044 // Add an edge to the start of the function.
2045 // We'll prune it out later, but it helps make diagnostics more uniform.
2046 const StackFrameContext *CalleeLC =
2047 Construct.getLocationContextForActivePath()->getStackFrame();
2048 const Decl *D = CalleeLC->getDecl();
2049 addEdgeToPath(Construct.getActivePath(), PrevLoc,
2050 PathDiagnosticLocation::createBegin(D, SM));
2051 }
2052
2053
2054 // Finally, prune the diagnostic path of uninteresting stuff.
2055 if (!Construct.PD->path.empty()) {
2056 if (R->shouldPrunePath() && Opts.ShouldPrunePaths) {
2057 bool stillHasNotes =
2058 removeUnneededCalls(Construct, Construct.getMutablePieces(), R);
2059 assert(stillHasNotes);
2060 (void)stillHasNotes;
2061 }
2062
2063 // Remove pop-up notes if needed.
2064 if (!Opts.ShouldAddPopUpNotes)
2065 removePopUpNotes(Construct.getMutablePieces());
2066
2067 // Redirect all call pieces to have valid locations.
2068 adjustCallLocations(Construct.getMutablePieces());
2069 removePiecesWithInvalidLocations(Construct.getMutablePieces());
2070
2071 if (PDC->shouldAddPathEdges()) {
2072
2073 // Reduce the number of edges from a very conservative set
2074 // to an aesthetically pleasing subset that conveys the
2075 // necessary information.
2076 OptimizedCallsSet OCS;
2077 while (optimizeEdges(Construct, Construct.getMutablePieces(), OCS)) {
2078 }
2079
2080 // Drop the very first function-entry edge. It's not really necessary
2081 // for top-level functions.
2082 dropFunctionEntryEdge(Construct, Construct.getMutablePieces());
2083 }
2084
2085 // Remove messages that are basically the same, and edges that may not
2086 // make sense.
2087 // We have to do this after edge optimization in the Extensive mode.
2088 removeRedundantMsgs(Construct.getMutablePieces());
2089 removeEdgesToDefaultInitializers(Construct.getMutablePieces());
2090 }
2091
2092 if (Opts.ShouldDisplayMacroExpansions)
2093 CompactMacroExpandedPieces(Construct.getMutablePieces(), SM);
2094
2095 return std::move(Construct.PD);
2096 }
2097
2098 //===----------------------------------------------------------------------===//
2099 // Methods for BugType and subclasses.
2100 //===----------------------------------------------------------------------===//
2101
anchor()2102 void BugType::anchor() {}
2103
anchor()2104 void BuiltinBug::anchor() {}
2105
2106 //===----------------------------------------------------------------------===//
2107 // Methods for BugReport and subclasses.
2108 //===----------------------------------------------------------------------===//
2109
2110 LLVM_ATTRIBUTE_USED static bool
isDependency(const CheckerRegistryData & Registry,StringRef CheckerName)2111 isDependency(const CheckerRegistryData &Registry, StringRef CheckerName) {
2112 for (const std::pair<StringRef, StringRef> &Pair : Registry.Dependencies) {
2113 if (Pair.second == CheckerName)
2114 return true;
2115 }
2116 return false;
2117 }
2118
isHidden(const CheckerRegistryData & Registry,StringRef CheckerName)2119 LLVM_ATTRIBUTE_USED static bool isHidden(const CheckerRegistryData &Registry,
2120 StringRef CheckerName) {
2121 for (const CheckerInfo &Checker : Registry.Checkers) {
2122 if (Checker.FullName == CheckerName)
2123 return Checker.IsHidden;
2124 }
2125 llvm_unreachable(
2126 "Checker name not found in CheckerRegistry -- did you retrieve it "
2127 "correctly from CheckerManager::getCurrentCheckerName?");
2128 }
2129
PathSensitiveBugReport(const BugType & bt,StringRef shortDesc,StringRef desc,const ExplodedNode * errorNode,PathDiagnosticLocation LocationToUnique,const Decl * DeclToUnique)2130 PathSensitiveBugReport::PathSensitiveBugReport(
2131 const BugType &bt, StringRef shortDesc, StringRef desc,
2132 const ExplodedNode *errorNode, PathDiagnosticLocation LocationToUnique,
2133 const Decl *DeclToUnique)
2134 : BugReport(Kind::PathSensitive, bt, shortDesc, desc), ErrorNode(errorNode),
2135 ErrorNodeRange(getStmt() ? getStmt()->getSourceRange() : SourceRange()),
2136 UniqueingLocation(LocationToUnique), UniqueingDecl(DeclToUnique) {
2137 assert(!isDependency(ErrorNode->getState()
2138 ->getAnalysisManager()
2139 .getCheckerManager()
2140 ->getCheckerRegistryData(),
2141 bt.getCheckerName()) &&
2142 "Some checkers depend on this one! We don't allow dependency "
2143 "checkers to emit warnings, because checkers should depend on "
2144 "*modeling*, not *diagnostics*.");
2145
2146 assert(
2147 (bt.getCheckerName().startswith("debug") ||
2148 !isHidden(ErrorNode->getState()
2149 ->getAnalysisManager()
2150 .getCheckerManager()
2151 ->getCheckerRegistryData(),
2152 bt.getCheckerName())) &&
2153 "Hidden checkers musn't emit diagnostics as they are by definition "
2154 "non-user facing!");
2155 }
2156
addVisitor(std::unique_ptr<BugReporterVisitor> visitor)2157 void PathSensitiveBugReport::addVisitor(
2158 std::unique_ptr<BugReporterVisitor> visitor) {
2159 if (!visitor)
2160 return;
2161
2162 llvm::FoldingSetNodeID ID;
2163 visitor->Profile(ID);
2164
2165 void *InsertPos = nullptr;
2166 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) {
2167 return;
2168 }
2169
2170 Callbacks.push_back(std::move(visitor));
2171 }
2172
clearVisitors()2173 void PathSensitiveBugReport::clearVisitors() {
2174 Callbacks.clear();
2175 }
2176
getDeclWithIssue() const2177 const Decl *PathSensitiveBugReport::getDeclWithIssue() const {
2178 const ExplodedNode *N = getErrorNode();
2179 if (!N)
2180 return nullptr;
2181
2182 const LocationContext *LC = N->getLocationContext();
2183 return LC->getStackFrame()->getDecl();
2184 }
2185
Profile(llvm::FoldingSetNodeID & hash) const2186 void BasicBugReport::Profile(llvm::FoldingSetNodeID& hash) const {
2187 hash.AddInteger(static_cast<int>(getKind()));
2188 hash.AddPointer(&BT);
2189 hash.AddString(Description);
2190 assert(Location.isValid());
2191 Location.Profile(hash);
2192
2193 for (SourceRange range : Ranges) {
2194 if (!range.isValid())
2195 continue;
2196 hash.Add(range.getBegin());
2197 hash.Add(range.getEnd());
2198 }
2199 }
2200
Profile(llvm::FoldingSetNodeID & hash) const2201 void PathSensitiveBugReport::Profile(llvm::FoldingSetNodeID &hash) const {
2202 hash.AddInteger(static_cast<int>(getKind()));
2203 hash.AddPointer(&BT);
2204 hash.AddString(Description);
2205 PathDiagnosticLocation UL = getUniqueingLocation();
2206 if (UL.isValid()) {
2207 UL.Profile(hash);
2208 } else {
2209 // TODO: The statement may be null if the report was emitted before any
2210 // statements were executed. In particular, some checkers by design
2211 // occasionally emit their reports in empty functions (that have no
2212 // statements in their body). Do we profile correctly in this case?
2213 hash.AddPointer(ErrorNode->getCurrentOrPreviousStmtForDiagnostics());
2214 }
2215
2216 for (SourceRange range : Ranges) {
2217 if (!range.isValid())
2218 continue;
2219 hash.Add(range.getBegin());
2220 hash.Add(range.getEnd());
2221 }
2222 }
2223
2224 template <class T>
insertToInterestingnessMap(llvm::DenseMap<T,bugreporter::TrackingKind> & InterestingnessMap,T Val,bugreporter::TrackingKind TKind)2225 static void insertToInterestingnessMap(
2226 llvm::DenseMap<T, bugreporter::TrackingKind> &InterestingnessMap, T Val,
2227 bugreporter::TrackingKind TKind) {
2228 auto Result = InterestingnessMap.insert({Val, TKind});
2229
2230 if (Result.second)
2231 return;
2232
2233 // Even if this symbol/region was already marked as interesting as a
2234 // condition, if we later mark it as interesting again but with
2235 // thorough tracking, overwrite it. Entities marked with thorough
2236 // interestiness are the most important (or most interesting, if you will),
2237 // and we wouldn't like to downplay their importance.
2238
2239 switch (TKind) {
2240 case bugreporter::TrackingKind::Thorough:
2241 Result.first->getSecond() = bugreporter::TrackingKind::Thorough;
2242 return;
2243 case bugreporter::TrackingKind::Condition:
2244 return;
2245 }
2246
2247 llvm_unreachable(
2248 "BugReport::markInteresting currently can only handle 2 different "
2249 "tracking kinds! Please define what tracking kind should this entitiy"
2250 "have, if it was already marked as interesting with a different kind!");
2251 }
2252
markInteresting(SymbolRef sym,bugreporter::TrackingKind TKind)2253 void PathSensitiveBugReport::markInteresting(SymbolRef sym,
2254 bugreporter::TrackingKind TKind) {
2255 if (!sym)
2256 return;
2257
2258 insertToInterestingnessMap(InterestingSymbols, sym, TKind);
2259
2260 if (const auto *meta = dyn_cast<SymbolMetadata>(sym))
2261 markInteresting(meta->getRegion(), TKind);
2262 }
2263
markInteresting(const MemRegion * R,bugreporter::TrackingKind TKind)2264 void PathSensitiveBugReport::markInteresting(const MemRegion *R,
2265 bugreporter::TrackingKind TKind) {
2266 if (!R)
2267 return;
2268
2269 R = R->getBaseRegion();
2270 insertToInterestingnessMap(InterestingRegions, R, TKind);
2271
2272 if (const auto *SR = dyn_cast<SymbolicRegion>(R))
2273 markInteresting(SR->getSymbol(), TKind);
2274 }
2275
markInteresting(SVal V,bugreporter::TrackingKind TKind)2276 void PathSensitiveBugReport::markInteresting(SVal V,
2277 bugreporter::TrackingKind TKind) {
2278 markInteresting(V.getAsRegion(), TKind);
2279 markInteresting(V.getAsSymbol(), TKind);
2280 }
2281
markInteresting(const LocationContext * LC)2282 void PathSensitiveBugReport::markInteresting(const LocationContext *LC) {
2283 if (!LC)
2284 return;
2285 InterestingLocationContexts.insert(LC);
2286 }
2287
2288 Optional<bugreporter::TrackingKind>
getInterestingnessKind(SVal V) const2289 PathSensitiveBugReport::getInterestingnessKind(SVal V) const {
2290 auto RKind = getInterestingnessKind(V.getAsRegion());
2291 auto SKind = getInterestingnessKind(V.getAsSymbol());
2292 if (!RKind)
2293 return SKind;
2294 if (!SKind)
2295 return RKind;
2296
2297 // If either is marked with throrough tracking, return that, we wouldn't like
2298 // to downplay a note's importance by 'only' mentioning it as a condition.
2299 switch(*RKind) {
2300 case bugreporter::TrackingKind::Thorough:
2301 return RKind;
2302 case bugreporter::TrackingKind::Condition:
2303 return SKind;
2304 }
2305
2306 llvm_unreachable(
2307 "BugReport::getInterestingnessKind currently can only handle 2 different "
2308 "tracking kinds! Please define what tracking kind should we return here "
2309 "when the kind of getAsRegion() and getAsSymbol() is different!");
2310 return None;
2311 }
2312
2313 Optional<bugreporter::TrackingKind>
getInterestingnessKind(SymbolRef sym) const2314 PathSensitiveBugReport::getInterestingnessKind(SymbolRef sym) const {
2315 if (!sym)
2316 return None;
2317 // We don't currently consider metadata symbols to be interesting
2318 // even if we know their region is interesting. Is that correct behavior?
2319 auto It = InterestingSymbols.find(sym);
2320 if (It == InterestingSymbols.end())
2321 return None;
2322 return It->getSecond();
2323 }
2324
2325 Optional<bugreporter::TrackingKind>
getInterestingnessKind(const MemRegion * R) const2326 PathSensitiveBugReport::getInterestingnessKind(const MemRegion *R) const {
2327 if (!R)
2328 return None;
2329
2330 R = R->getBaseRegion();
2331 auto It = InterestingRegions.find(R);
2332 if (It != InterestingRegions.end())
2333 return It->getSecond();
2334
2335 if (const auto *SR = dyn_cast<SymbolicRegion>(R))
2336 return getInterestingnessKind(SR->getSymbol());
2337 return None;
2338 }
2339
isInteresting(SVal V) const2340 bool PathSensitiveBugReport::isInteresting(SVal V) const {
2341 return getInterestingnessKind(V).hasValue();
2342 }
2343
isInteresting(SymbolRef sym) const2344 bool PathSensitiveBugReport::isInteresting(SymbolRef sym) const {
2345 return getInterestingnessKind(sym).hasValue();
2346 }
2347
isInteresting(const MemRegion * R) const2348 bool PathSensitiveBugReport::isInteresting(const MemRegion *R) const {
2349 return getInterestingnessKind(R).hasValue();
2350 }
2351
isInteresting(const LocationContext * LC) const2352 bool PathSensitiveBugReport::isInteresting(const LocationContext *LC) const {
2353 if (!LC)
2354 return false;
2355 return InterestingLocationContexts.count(LC);
2356 }
2357
getStmt() const2358 const Stmt *PathSensitiveBugReport::getStmt() const {
2359 if (!ErrorNode)
2360 return nullptr;
2361
2362 ProgramPoint ProgP = ErrorNode->getLocation();
2363 const Stmt *S = nullptr;
2364
2365 if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) {
2366 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit();
2367 if (BE->getBlock() == &Exit)
2368 S = ErrorNode->getPreviousStmtForDiagnostics();
2369 }
2370 if (!S)
2371 S = ErrorNode->getStmtForDiagnostics();
2372
2373 return S;
2374 }
2375
2376 ArrayRef<SourceRange>
getRanges() const2377 PathSensitiveBugReport::getRanges() const {
2378 // If no custom ranges, add the range of the statement corresponding to
2379 // the error node.
2380 if (Ranges.empty() && isa_and_nonnull<Expr>(getStmt()))
2381 return ErrorNodeRange;
2382
2383 return Ranges;
2384 }
2385
2386 PathDiagnosticLocation
getLocation() const2387 PathSensitiveBugReport::getLocation() const {
2388 assert(ErrorNode && "Cannot create a location with a null node.");
2389 const Stmt *S = ErrorNode->getStmtForDiagnostics();
2390 ProgramPoint P = ErrorNode->getLocation();
2391 const LocationContext *LC = P.getLocationContext();
2392 SourceManager &SM =
2393 ErrorNode->getState()->getStateManager().getContext().getSourceManager();
2394
2395 if (!S) {
2396 // If this is an implicit call, return the implicit call point location.
2397 if (Optional<PreImplicitCall> PIE = P.getAs<PreImplicitCall>())
2398 return PathDiagnosticLocation(PIE->getLocation(), SM);
2399 if (auto FE = P.getAs<FunctionExitPoint>()) {
2400 if (const ReturnStmt *RS = FE->getStmt())
2401 return PathDiagnosticLocation::createBegin(RS, SM, LC);
2402 }
2403 S = ErrorNode->getNextStmtForDiagnostics();
2404 }
2405
2406 if (S) {
2407 // For member expressions, return the location of the '.' or '->'.
2408 if (const auto *ME = dyn_cast<MemberExpr>(S))
2409 return PathDiagnosticLocation::createMemberLoc(ME, SM);
2410
2411 // For binary operators, return the location of the operator.
2412 if (const auto *B = dyn_cast<BinaryOperator>(S))
2413 return PathDiagnosticLocation::createOperatorLoc(B, SM);
2414
2415 if (P.getAs<PostStmtPurgeDeadSymbols>())
2416 return PathDiagnosticLocation::createEnd(S, SM, LC);
2417
2418 if (S->getBeginLoc().isValid())
2419 return PathDiagnosticLocation(S, SM, LC);
2420
2421 return PathDiagnosticLocation(
2422 PathDiagnosticLocation::getValidSourceLocation(S, LC), SM);
2423 }
2424
2425 return PathDiagnosticLocation::createDeclEnd(ErrorNode->getLocationContext(),
2426 SM);
2427 }
2428
2429 //===----------------------------------------------------------------------===//
2430 // Methods for BugReporter and subclasses.
2431 //===----------------------------------------------------------------------===//
2432
getGraph() const2433 const ExplodedGraph &PathSensitiveBugReporter::getGraph() const {
2434 return Eng.getGraph();
2435 }
2436
getStateManager() const2437 ProgramStateManager &PathSensitiveBugReporter::getStateManager() const {
2438 return Eng.getStateManager();
2439 }
2440
BugReporter(BugReporterData & d)2441 BugReporter::BugReporter(BugReporterData &d) : D(d) {}
~BugReporter()2442 BugReporter::~BugReporter() {
2443 // Make sure reports are flushed.
2444 assert(StrBugTypes.empty() &&
2445 "Destroying BugReporter before diagnostics are emitted!");
2446
2447 // Free the bug reports we are tracking.
2448 for (const auto I : EQClassesVector)
2449 delete I;
2450 }
2451
FlushReports()2452 void BugReporter::FlushReports() {
2453 // We need to flush reports in deterministic order to ensure the order
2454 // of the reports is consistent between runs.
2455 for (const auto EQ : EQClassesVector)
2456 FlushReport(*EQ);
2457
2458 // BugReporter owns and deletes only BugTypes created implicitly through
2459 // EmitBasicReport.
2460 // FIXME: There are leaks from checkers that assume that the BugTypes they
2461 // create will be destroyed by the BugReporter.
2462 StrBugTypes.clear();
2463 }
2464
2465 //===----------------------------------------------------------------------===//
2466 // PathDiagnostics generation.
2467 //===----------------------------------------------------------------------===//
2468
2469 namespace {
2470
2471 /// A wrapper around an ExplodedGraph that contains a single path from the root
2472 /// to the error node.
2473 class BugPathInfo {
2474 public:
2475 std::unique_ptr<ExplodedGraph> BugPath;
2476 PathSensitiveBugReport *Report;
2477 const ExplodedNode *ErrorNode;
2478 };
2479
2480 /// A wrapper around an ExplodedGraph whose leafs are all error nodes. Can
2481 /// conveniently retrieve bug paths from a single error node to the root.
2482 class BugPathGetter {
2483 std::unique_ptr<ExplodedGraph> TrimmedGraph;
2484
2485 using PriorityMapTy = llvm::DenseMap<const ExplodedNode *, unsigned>;
2486
2487 /// Assign each node with its distance from the root.
2488 PriorityMapTy PriorityMap;
2489
2490 /// Since the getErrorNode() or BugReport refers to the original ExplodedGraph,
2491 /// we need to pair it to the error node of the constructed trimmed graph.
2492 using ReportNewNodePair =
2493 std::pair<PathSensitiveBugReport *, const ExplodedNode *>;
2494 SmallVector<ReportNewNodePair, 32> ReportNodes;
2495
2496 BugPathInfo CurrentBugPath;
2497
2498 /// A helper class for sorting ExplodedNodes by priority.
2499 template <bool Descending>
2500 class PriorityCompare {
2501 const PriorityMapTy &PriorityMap;
2502
2503 public:
PriorityCompare(const PriorityMapTy & M)2504 PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {}
2505
operator ()(const ExplodedNode * LHS,const ExplodedNode * RHS) const2506 bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const {
2507 PriorityMapTy::const_iterator LI = PriorityMap.find(LHS);
2508 PriorityMapTy::const_iterator RI = PriorityMap.find(RHS);
2509 PriorityMapTy::const_iterator E = PriorityMap.end();
2510
2511 if (LI == E)
2512 return Descending;
2513 if (RI == E)
2514 return !Descending;
2515
2516 return Descending ? LI->second > RI->second
2517 : LI->second < RI->second;
2518 }
2519
operator ()(const ReportNewNodePair & LHS,const ReportNewNodePair & RHS) const2520 bool operator()(const ReportNewNodePair &LHS,
2521 const ReportNewNodePair &RHS) const {
2522 return (*this)(LHS.second, RHS.second);
2523 }
2524 };
2525
2526 public:
2527 BugPathGetter(const ExplodedGraph *OriginalGraph,
2528 ArrayRef<PathSensitiveBugReport *> &bugReports);
2529
2530 BugPathInfo *getNextBugPath();
2531 };
2532
2533 } // namespace
2534
BugPathGetter(const ExplodedGraph * OriginalGraph,ArrayRef<PathSensitiveBugReport * > & bugReports)2535 BugPathGetter::BugPathGetter(const ExplodedGraph *OriginalGraph,
2536 ArrayRef<PathSensitiveBugReport *> &bugReports) {
2537 SmallVector<const ExplodedNode *, 32> Nodes;
2538 for (const auto I : bugReports) {
2539 assert(I->isValid() &&
2540 "We only allow BugReporterVisitors and BugReporter itself to "
2541 "invalidate reports!");
2542 Nodes.emplace_back(I->getErrorNode());
2543 }
2544
2545 // The trimmed graph is created in the body of the constructor to ensure
2546 // that the DenseMaps have been initialized already.
2547 InterExplodedGraphMap ForwardMap;
2548 TrimmedGraph = OriginalGraph->trim(Nodes, &ForwardMap);
2549
2550 // Find the (first) error node in the trimmed graph. We just need to consult
2551 // the node map which maps from nodes in the original graph to nodes
2552 // in the new graph.
2553 llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes;
2554
2555 for (PathSensitiveBugReport *Report : bugReports) {
2556 const ExplodedNode *NewNode = ForwardMap.lookup(Report->getErrorNode());
2557 assert(NewNode &&
2558 "Failed to construct a trimmed graph that contains this error "
2559 "node!");
2560 ReportNodes.emplace_back(Report, NewNode);
2561 RemainingNodes.insert(NewNode);
2562 }
2563
2564 assert(!RemainingNodes.empty() && "No error node found in the trimmed graph");
2565
2566 // Perform a forward BFS to find all the shortest paths.
2567 std::queue<const ExplodedNode *> WS;
2568
2569 assert(TrimmedGraph->num_roots() == 1);
2570 WS.push(*TrimmedGraph->roots_begin());
2571 unsigned Priority = 0;
2572
2573 while (!WS.empty()) {
2574 const ExplodedNode *Node = WS.front();
2575 WS.pop();
2576
2577 PriorityMapTy::iterator PriorityEntry;
2578 bool IsNew;
2579 std::tie(PriorityEntry, IsNew) = PriorityMap.insert({Node, Priority});
2580 ++Priority;
2581
2582 if (!IsNew) {
2583 assert(PriorityEntry->second <= Priority);
2584 continue;
2585 }
2586
2587 if (RemainingNodes.erase(Node))
2588 if (RemainingNodes.empty())
2589 break;
2590
2591 for (const ExplodedNode *Succ : Node->succs())
2592 WS.push(Succ);
2593 }
2594
2595 // Sort the error paths from longest to shortest.
2596 llvm::sort(ReportNodes, PriorityCompare<true>(PriorityMap));
2597 }
2598
getNextBugPath()2599 BugPathInfo *BugPathGetter::getNextBugPath() {
2600 if (ReportNodes.empty())
2601 return nullptr;
2602
2603 const ExplodedNode *OrigN;
2604 std::tie(CurrentBugPath.Report, OrigN) = ReportNodes.pop_back_val();
2605 assert(PriorityMap.find(OrigN) != PriorityMap.end() &&
2606 "error node not accessible from root");
2607
2608 // Create a new graph with a single path. This is the graph that will be
2609 // returned to the caller.
2610 auto GNew = std::make_unique<ExplodedGraph>();
2611
2612 // Now walk from the error node up the BFS path, always taking the
2613 // predeccessor with the lowest number.
2614 ExplodedNode *Succ = nullptr;
2615 while (true) {
2616 // Create the equivalent node in the new graph with the same state
2617 // and location.
2618 ExplodedNode *NewN = GNew->createUncachedNode(
2619 OrigN->getLocation(), OrigN->getState(),
2620 OrigN->getID(), OrigN->isSink());
2621
2622 // Link up the new node with the previous node.
2623 if (Succ)
2624 Succ->addPredecessor(NewN, *GNew);
2625 else
2626 CurrentBugPath.ErrorNode = NewN;
2627
2628 Succ = NewN;
2629
2630 // Are we at the final node?
2631 if (OrigN->pred_empty()) {
2632 GNew->addRoot(NewN);
2633 break;
2634 }
2635
2636 // Find the next predeccessor node. We choose the node that is marked
2637 // with the lowest BFS number.
2638 OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(),
2639 PriorityCompare<false>(PriorityMap));
2640 }
2641
2642 CurrentBugPath.BugPath = std::move(GNew);
2643
2644 return &CurrentBugPath;
2645 }
2646
2647 /// CompactMacroExpandedPieces - This function postprocesses a PathDiagnostic
2648 /// object and collapses PathDiagosticPieces that are expanded by macros.
CompactMacroExpandedPieces(PathPieces & path,const SourceManager & SM)2649 static void CompactMacroExpandedPieces(PathPieces &path,
2650 const SourceManager& SM) {
2651 using MacroStackTy = std::vector<
2652 std::pair<std::shared_ptr<PathDiagnosticMacroPiece>, SourceLocation>>;
2653
2654 using PiecesTy = std::vector<PathDiagnosticPieceRef>;
2655
2656 MacroStackTy MacroStack;
2657 PiecesTy Pieces;
2658
2659 for (PathPieces::const_iterator I = path.begin(), E = path.end();
2660 I != E; ++I) {
2661 const auto &piece = *I;
2662
2663 // Recursively compact calls.
2664 if (auto *call = dyn_cast<PathDiagnosticCallPiece>(&*piece)) {
2665 CompactMacroExpandedPieces(call->path, SM);
2666 }
2667
2668 // Get the location of the PathDiagnosticPiece.
2669 const FullSourceLoc Loc = piece->getLocation().asLocation();
2670
2671 // Determine the instantiation location, which is the location we group
2672 // related PathDiagnosticPieces.
2673 SourceLocation InstantiationLoc = Loc.isMacroID() ?
2674 SM.getExpansionLoc(Loc) :
2675 SourceLocation();
2676
2677 if (Loc.isFileID()) {
2678 MacroStack.clear();
2679 Pieces.push_back(piece);
2680 continue;
2681 }
2682
2683 assert(Loc.isMacroID());
2684
2685 // Is the PathDiagnosticPiece within the same macro group?
2686 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) {
2687 MacroStack.back().first->subPieces.push_back(piece);
2688 continue;
2689 }
2690
2691 // We aren't in the same group. Are we descending into a new macro
2692 // or are part of an old one?
2693 std::shared_ptr<PathDiagnosticMacroPiece> MacroGroup;
2694
2695 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ?
2696 SM.getExpansionLoc(Loc) :
2697 SourceLocation();
2698
2699 // Walk the entire macro stack.
2700 while (!MacroStack.empty()) {
2701 if (InstantiationLoc == MacroStack.back().second) {
2702 MacroGroup = MacroStack.back().first;
2703 break;
2704 }
2705
2706 if (ParentInstantiationLoc == MacroStack.back().second) {
2707 MacroGroup = MacroStack.back().first;
2708 break;
2709 }
2710
2711 MacroStack.pop_back();
2712 }
2713
2714 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) {
2715 // Create a new macro group and add it to the stack.
2716 auto NewGroup = std::make_shared<PathDiagnosticMacroPiece>(
2717 PathDiagnosticLocation::createSingleLocation(piece->getLocation()));
2718
2719 if (MacroGroup)
2720 MacroGroup->subPieces.push_back(NewGroup);
2721 else {
2722 assert(InstantiationLoc.isFileID());
2723 Pieces.push_back(NewGroup);
2724 }
2725
2726 MacroGroup = NewGroup;
2727 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc));
2728 }
2729
2730 // Finally, add the PathDiagnosticPiece to the group.
2731 MacroGroup->subPieces.push_back(piece);
2732 }
2733
2734 // Now take the pieces and construct a new PathDiagnostic.
2735 path.clear();
2736
2737 path.insert(path.end(), Pieces.begin(), Pieces.end());
2738 }
2739
2740 /// Generate notes from all visitors.
2741 /// Notes associated with {@code ErrorNode} are generated using
2742 /// {@code getEndPath}, and the rest are generated with {@code VisitNode}.
2743 static std::unique_ptr<VisitorsDiagnosticsTy>
generateVisitorsDiagnostics(PathSensitiveBugReport * R,const ExplodedNode * ErrorNode,BugReporterContext & BRC)2744 generateVisitorsDiagnostics(PathSensitiveBugReport *R,
2745 const ExplodedNode *ErrorNode,
2746 BugReporterContext &BRC) {
2747 std::unique_ptr<VisitorsDiagnosticsTy> Notes =
2748 std::make_unique<VisitorsDiagnosticsTy>();
2749 PathSensitiveBugReport::VisitorList visitors;
2750
2751 // Run visitors on all nodes starting from the node *before* the last one.
2752 // The last node is reserved for notes generated with {@code getEndPath}.
2753 const ExplodedNode *NextNode = ErrorNode->getFirstPred();
2754 while (NextNode) {
2755
2756 // At each iteration, move all visitors from report to visitor list. This is
2757 // important, because the Profile() functions of the visitors make sure that
2758 // a visitor isn't added multiple times for the same node, but it's fine
2759 // to add the a visitor with Profile() for different nodes (e.g. tracking
2760 // a region at different points of the symbolic execution).
2761 for (std::unique_ptr<BugReporterVisitor> &Visitor : R->visitors())
2762 visitors.push_back(std::move(Visitor));
2763
2764 R->clearVisitors();
2765
2766 const ExplodedNode *Pred = NextNode->getFirstPred();
2767 if (!Pred) {
2768 PathDiagnosticPieceRef LastPiece;
2769 for (auto &V : visitors) {
2770 V->finalizeVisitor(BRC, ErrorNode, *R);
2771
2772 if (auto Piece = V->getEndPath(BRC, ErrorNode, *R)) {
2773 assert(!LastPiece &&
2774 "There can only be one final piece in a diagnostic.");
2775 assert(Piece->getKind() == PathDiagnosticPiece::Kind::Event &&
2776 "The final piece must contain a message!");
2777 LastPiece = std::move(Piece);
2778 (*Notes)[ErrorNode].push_back(LastPiece);
2779 }
2780 }
2781 break;
2782 }
2783
2784 for (auto &V : visitors) {
2785 auto P = V->VisitNode(NextNode, BRC, *R);
2786 if (P)
2787 (*Notes)[NextNode].push_back(std::move(P));
2788 }
2789
2790 if (!R->isValid())
2791 break;
2792
2793 NextNode = Pred;
2794 }
2795
2796 return Notes;
2797 }
2798
findValidReport(ArrayRef<PathSensitiveBugReport * > & bugReports,PathSensitiveBugReporter & Reporter)2799 Optional<PathDiagnosticBuilder> PathDiagnosticBuilder::findValidReport(
2800 ArrayRef<PathSensitiveBugReport *> &bugReports,
2801 PathSensitiveBugReporter &Reporter) {
2802
2803 BugPathGetter BugGraph(&Reporter.getGraph(), bugReports);
2804
2805 while (BugPathInfo *BugPath = BugGraph.getNextBugPath()) {
2806 // Find the BugReport with the original location.
2807 PathSensitiveBugReport *R = BugPath->Report;
2808 assert(R && "No original report found for sliced graph.");
2809 assert(R->isValid() && "Report selected by trimmed graph marked invalid.");
2810 const ExplodedNode *ErrorNode = BugPath->ErrorNode;
2811
2812 // Register refutation visitors first, if they mark the bug invalid no
2813 // further analysis is required
2814 R->addVisitor(std::make_unique<LikelyFalsePositiveSuppressionBRVisitor>());
2815
2816 // Register additional node visitors.
2817 R->addVisitor(std::make_unique<NilReceiverBRVisitor>());
2818 R->addVisitor(std::make_unique<ConditionBRVisitor>());
2819 R->addVisitor(std::make_unique<TagVisitor>());
2820
2821 BugReporterContext BRC(Reporter);
2822
2823 // Run all visitors on a given graph, once.
2824 std::unique_ptr<VisitorsDiagnosticsTy> visitorNotes =
2825 generateVisitorsDiagnostics(R, ErrorNode, BRC);
2826
2827 if (R->isValid()) {
2828 if (Reporter.getAnalyzerOptions().ShouldCrosscheckWithZ3) {
2829 // If crosscheck is enabled, remove all visitors, add the refutation
2830 // visitor and check again
2831 R->clearVisitors();
2832 R->addVisitor(std::make_unique<FalsePositiveRefutationBRVisitor>());
2833
2834 // We don't overwrite the notes inserted by other visitors because the
2835 // refutation manager does not add any new note to the path
2836 generateVisitorsDiagnostics(R, BugPath->ErrorNode, BRC);
2837 }
2838
2839 // Check if the bug is still valid
2840 if (R->isValid())
2841 return PathDiagnosticBuilder(
2842 std::move(BRC), std::move(BugPath->BugPath), BugPath->Report,
2843 BugPath->ErrorNode, std::move(visitorNotes));
2844 }
2845 }
2846
2847 return {};
2848 }
2849
2850 std::unique_ptr<DiagnosticForConsumerMapTy>
generatePathDiagnostics(ArrayRef<PathDiagnosticConsumer * > consumers,ArrayRef<PathSensitiveBugReport * > & bugReports)2851 PathSensitiveBugReporter::generatePathDiagnostics(
2852 ArrayRef<PathDiagnosticConsumer *> consumers,
2853 ArrayRef<PathSensitiveBugReport *> &bugReports) {
2854 assert(!bugReports.empty());
2855
2856 auto Out = std::make_unique<DiagnosticForConsumerMapTy>();
2857
2858 Optional<PathDiagnosticBuilder> PDB =
2859 PathDiagnosticBuilder::findValidReport(bugReports, *this);
2860
2861 if (PDB) {
2862 for (PathDiagnosticConsumer *PC : consumers) {
2863 if (std::unique_ptr<PathDiagnostic> PD = PDB->generate(PC)) {
2864 (*Out)[PC] = std::move(PD);
2865 }
2866 }
2867 }
2868
2869 return Out;
2870 }
2871
emitReport(std::unique_ptr<BugReport> R)2872 void BugReporter::emitReport(std::unique_ptr<BugReport> R) {
2873 bool ValidSourceLoc = R->getLocation().isValid();
2874 assert(ValidSourceLoc);
2875 // If we mess up in a release build, we'd still prefer to just drop the bug
2876 // instead of trying to go on.
2877 if (!ValidSourceLoc)
2878 return;
2879
2880 // Compute the bug report's hash to determine its equivalence class.
2881 llvm::FoldingSetNodeID ID;
2882 R->Profile(ID);
2883
2884 // Lookup the equivance class. If there isn't one, create it.
2885 void *InsertPos;
2886 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos);
2887
2888 if (!EQ) {
2889 EQ = new BugReportEquivClass(std::move(R));
2890 EQClasses.InsertNode(EQ, InsertPos);
2891 EQClassesVector.push_back(EQ);
2892 } else
2893 EQ->AddReport(std::move(R));
2894 }
2895
emitReport(std::unique_ptr<BugReport> R)2896 void PathSensitiveBugReporter::emitReport(std::unique_ptr<BugReport> R) {
2897 if (auto PR = dyn_cast<PathSensitiveBugReport>(R.get()))
2898 if (const ExplodedNode *E = PR->getErrorNode()) {
2899 // An error node must either be a sink or have a tag, otherwise
2900 // it could get reclaimed before the path diagnostic is created.
2901 assert((E->isSink() || E->getLocation().getTag()) &&
2902 "Error node must either be a sink or have a tag");
2903
2904 const AnalysisDeclContext *DeclCtx =
2905 E->getLocationContext()->getAnalysisDeclContext();
2906 // The source of autosynthesized body can be handcrafted AST or a model
2907 // file. The locations from handcrafted ASTs have no valid source
2908 // locations and have to be discarded. Locations from model files should
2909 // be preserved for processing and reporting.
2910 if (DeclCtx->isBodyAutosynthesized() &&
2911 !DeclCtx->isBodyAutosynthesizedFromModelFile())
2912 return;
2913 }
2914
2915 BugReporter::emitReport(std::move(R));
2916 }
2917
2918 //===----------------------------------------------------------------------===//
2919 // Emitting reports in equivalence classes.
2920 //===----------------------------------------------------------------------===//
2921
2922 namespace {
2923
2924 struct FRIEC_WLItem {
2925 const ExplodedNode *N;
2926 ExplodedNode::const_succ_iterator I, E;
2927
FRIEC_WLItem__anon3f33eaf90311::FRIEC_WLItem2928 FRIEC_WLItem(const ExplodedNode *n)
2929 : N(n), I(N->succ_begin()), E(N->succ_end()) {}
2930 };
2931
2932 } // namespace
2933
findReportInEquivalenceClass(BugReportEquivClass & EQ,SmallVectorImpl<BugReport * > & bugReports)2934 BugReport *PathSensitiveBugReporter::findReportInEquivalenceClass(
2935 BugReportEquivClass &EQ, SmallVectorImpl<BugReport *> &bugReports) {
2936 // If we don't need to suppress any of the nodes because they are
2937 // post-dominated by a sink, simply add all the nodes in the equivalence class
2938 // to 'Nodes'. Any of the reports will serve as a "representative" report.
2939 assert(EQ.getReports().size() > 0);
2940 const BugType& BT = EQ.getReports()[0]->getBugType();
2941 if (!BT.isSuppressOnSink()) {
2942 BugReport *R = EQ.getReports()[0].get();
2943 for (auto &J : EQ.getReports()) {
2944 if (auto *PR = dyn_cast<PathSensitiveBugReport>(J.get())) {
2945 R = PR;
2946 bugReports.push_back(PR);
2947 }
2948 }
2949 return R;
2950 }
2951
2952 // For bug reports that should be suppressed when all paths are post-dominated
2953 // by a sink node, iterate through the reports in the equivalence class
2954 // until we find one that isn't post-dominated (if one exists). We use a
2955 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write
2956 // this as a recursive function, but we don't want to risk blowing out the
2957 // stack for very long paths.
2958 BugReport *exampleReport = nullptr;
2959
2960 for (const auto &I: EQ.getReports()) {
2961 auto *R = dyn_cast<PathSensitiveBugReport>(I.get());
2962 if (!R)
2963 continue;
2964
2965 const ExplodedNode *errorNode = R->getErrorNode();
2966 if (errorNode->isSink()) {
2967 llvm_unreachable(
2968 "BugType::isSuppressSink() should not be 'true' for sink end nodes");
2969 }
2970 // No successors? By definition this nodes isn't post-dominated by a sink.
2971 if (errorNode->succ_empty()) {
2972 bugReports.push_back(R);
2973 if (!exampleReport)
2974 exampleReport = R;
2975 continue;
2976 }
2977
2978 // See if we are in a no-return CFG block. If so, treat this similarly
2979 // to being post-dominated by a sink. This works better when the analysis
2980 // is incomplete and we have never reached the no-return function call(s)
2981 // that we'd inevitably bump into on this path.
2982 if (const CFGBlock *ErrorB = errorNode->getCFGBlock())
2983 if (ErrorB->isInevitablySinking())
2984 continue;
2985
2986 // At this point we know that 'N' is not a sink and it has at least one
2987 // successor. Use a DFS worklist to find a non-sink end-of-path node.
2988 using WLItem = FRIEC_WLItem;
2989 using DFSWorkList = SmallVector<WLItem, 10>;
2990
2991 llvm::DenseMap<const ExplodedNode *, unsigned> Visited;
2992
2993 DFSWorkList WL;
2994 WL.push_back(errorNode);
2995 Visited[errorNode] = 1;
2996
2997 while (!WL.empty()) {
2998 WLItem &WI = WL.back();
2999 assert(!WI.N->succ_empty());
3000
3001 for (; WI.I != WI.E; ++WI.I) {
3002 const ExplodedNode *Succ = *WI.I;
3003 // End-of-path node?
3004 if (Succ->succ_empty()) {
3005 // If we found an end-of-path node that is not a sink.
3006 if (!Succ->isSink()) {
3007 bugReports.push_back(R);
3008 if (!exampleReport)
3009 exampleReport = R;
3010 WL.clear();
3011 break;
3012 }
3013 // Found a sink? Continue on to the next successor.
3014 continue;
3015 }
3016 // Mark the successor as visited. If it hasn't been explored,
3017 // enqueue it to the DFS worklist.
3018 unsigned &mark = Visited[Succ];
3019 if (!mark) {
3020 mark = 1;
3021 WL.push_back(Succ);
3022 break;
3023 }
3024 }
3025
3026 // The worklist may have been cleared at this point. First
3027 // check if it is empty before checking the last item.
3028 if (!WL.empty() && &WL.back() == &WI)
3029 WL.pop_back();
3030 }
3031 }
3032
3033 // ExampleReport will be NULL if all the nodes in the equivalence class
3034 // were post-dominated by sinks.
3035 return exampleReport;
3036 }
3037
FlushReport(BugReportEquivClass & EQ)3038 void BugReporter::FlushReport(BugReportEquivClass& EQ) {
3039 SmallVector<BugReport*, 10> bugReports;
3040 BugReport *report = findReportInEquivalenceClass(EQ, bugReports);
3041 if (!report)
3042 return;
3043
3044 ArrayRef<PathDiagnosticConsumer*> Consumers = getPathDiagnosticConsumers();
3045 std::unique_ptr<DiagnosticForConsumerMapTy> Diagnostics =
3046 generateDiagnosticForConsumerMap(report, Consumers, bugReports);
3047
3048 for (auto &P : *Diagnostics) {
3049 PathDiagnosticConsumer *Consumer = P.first;
3050 std::unique_ptr<PathDiagnostic> &PD = P.second;
3051
3052 // If the path is empty, generate a single step path with the location
3053 // of the issue.
3054 if (PD->path.empty()) {
3055 PathDiagnosticLocation L = report->getLocation();
3056 auto piece = std::make_unique<PathDiagnosticEventPiece>(
3057 L, report->getDescription());
3058 for (SourceRange Range : report->getRanges())
3059 piece->addRange(Range);
3060 PD->setEndOfPath(std::move(piece));
3061 }
3062
3063 PathPieces &Pieces = PD->getMutablePieces();
3064 if (getAnalyzerOptions().ShouldDisplayNotesAsEvents) {
3065 // For path diagnostic consumers that don't support extra notes,
3066 // we may optionally convert those to path notes.
3067 for (auto I = report->getNotes().rbegin(),
3068 E = report->getNotes().rend(); I != E; ++I) {
3069 PathDiagnosticNotePiece *Piece = I->get();
3070 auto ConvertedPiece = std::make_shared<PathDiagnosticEventPiece>(
3071 Piece->getLocation(), Piece->getString());
3072 for (const auto &R: Piece->getRanges())
3073 ConvertedPiece->addRange(R);
3074
3075 Pieces.push_front(std::move(ConvertedPiece));
3076 }
3077 } else {
3078 for (auto I = report->getNotes().rbegin(),
3079 E = report->getNotes().rend(); I != E; ++I)
3080 Pieces.push_front(*I);
3081 }
3082
3083 for (const auto &I : report->getFixits())
3084 Pieces.back()->addFixit(I);
3085
3086 updateExecutedLinesWithDiagnosticPieces(*PD);
3087 Consumer->HandlePathDiagnostic(std::move(PD));
3088 }
3089 }
3090
3091 /// Insert all lines participating in the function signature \p Signature
3092 /// into \p ExecutedLines.
populateExecutedLinesWithFunctionSignature(const Decl * Signature,const SourceManager & SM,FilesToLineNumsMap & ExecutedLines)3093 static void populateExecutedLinesWithFunctionSignature(
3094 const Decl *Signature, const SourceManager &SM,
3095 FilesToLineNumsMap &ExecutedLines) {
3096 SourceRange SignatureSourceRange;
3097 const Stmt* Body = Signature->getBody();
3098 if (const auto FD = dyn_cast<FunctionDecl>(Signature)) {
3099 SignatureSourceRange = FD->getSourceRange();
3100 } else if (const auto OD = dyn_cast<ObjCMethodDecl>(Signature)) {
3101 SignatureSourceRange = OD->getSourceRange();
3102 } else {
3103 return;
3104 }
3105 SourceLocation Start = SignatureSourceRange.getBegin();
3106 SourceLocation End = Body ? Body->getSourceRange().getBegin()
3107 : SignatureSourceRange.getEnd();
3108 if (!Start.isValid() || !End.isValid())
3109 return;
3110 unsigned StartLine = SM.getExpansionLineNumber(Start);
3111 unsigned EndLine = SM.getExpansionLineNumber(End);
3112
3113 FileID FID = SM.getFileID(SM.getExpansionLoc(Start));
3114 for (unsigned Line = StartLine; Line <= EndLine; Line++)
3115 ExecutedLines[FID].insert(Line);
3116 }
3117
populateExecutedLinesWithStmt(const Stmt * S,const SourceManager & SM,FilesToLineNumsMap & ExecutedLines)3118 static void populateExecutedLinesWithStmt(
3119 const Stmt *S, const SourceManager &SM,
3120 FilesToLineNumsMap &ExecutedLines) {
3121 SourceLocation Loc = S->getSourceRange().getBegin();
3122 if (!Loc.isValid())
3123 return;
3124 SourceLocation ExpansionLoc = SM.getExpansionLoc(Loc);
3125 FileID FID = SM.getFileID(ExpansionLoc);
3126 unsigned LineNo = SM.getExpansionLineNumber(ExpansionLoc);
3127 ExecutedLines[FID].insert(LineNo);
3128 }
3129
3130 /// \return all executed lines including function signatures on the path
3131 /// starting from \p N.
3132 static std::unique_ptr<FilesToLineNumsMap>
findExecutedLines(const SourceManager & SM,const ExplodedNode * N)3133 findExecutedLines(const SourceManager &SM, const ExplodedNode *N) {
3134 auto ExecutedLines = std::make_unique<FilesToLineNumsMap>();
3135
3136 while (N) {
3137 if (N->getFirstPred() == nullptr) {
3138 // First node: show signature of the entrance point.
3139 const Decl *D = N->getLocationContext()->getDecl();
3140 populateExecutedLinesWithFunctionSignature(D, SM, *ExecutedLines);
3141 } else if (auto CE = N->getLocationAs<CallEnter>()) {
3142 // Inlined function: show signature.
3143 const Decl* D = CE->getCalleeContext()->getDecl();
3144 populateExecutedLinesWithFunctionSignature(D, SM, *ExecutedLines);
3145 } else if (const Stmt *S = N->getStmtForDiagnostics()) {
3146 populateExecutedLinesWithStmt(S, SM, *ExecutedLines);
3147
3148 // Show extra context for some parent kinds.
3149 const Stmt *P = N->getParentMap().getParent(S);
3150
3151 // The path exploration can die before the node with the associated
3152 // return statement is generated, but we do want to show the whole
3153 // return.
3154 if (const auto *RS = dyn_cast_or_null<ReturnStmt>(P)) {
3155 populateExecutedLinesWithStmt(RS, SM, *ExecutedLines);
3156 P = N->getParentMap().getParent(RS);
3157 }
3158
3159 if (P && (isa<SwitchCase>(P) || isa<LabelStmt>(P)))
3160 populateExecutedLinesWithStmt(P, SM, *ExecutedLines);
3161 }
3162
3163 N = N->getFirstPred();
3164 }
3165 return ExecutedLines;
3166 }
3167
3168 std::unique_ptr<DiagnosticForConsumerMapTy>
generateDiagnosticForConsumerMap(BugReport * exampleReport,ArrayRef<PathDiagnosticConsumer * > consumers,ArrayRef<BugReport * > bugReports)3169 BugReporter::generateDiagnosticForConsumerMap(
3170 BugReport *exampleReport, ArrayRef<PathDiagnosticConsumer *> consumers,
3171 ArrayRef<BugReport *> bugReports) {
3172 auto *basicReport = cast<BasicBugReport>(exampleReport);
3173 auto Out = std::make_unique<DiagnosticForConsumerMapTy>();
3174 for (auto *Consumer : consumers)
3175 (*Out)[Consumer] = generateDiagnosticForBasicReport(basicReport);
3176 return Out;
3177 }
3178
3179 static PathDiagnosticCallPiece *
getFirstStackedCallToHeaderFile(PathDiagnosticCallPiece * CP,const SourceManager & SMgr)3180 getFirstStackedCallToHeaderFile(PathDiagnosticCallPiece *CP,
3181 const SourceManager &SMgr) {
3182 SourceLocation CallLoc = CP->callEnter.asLocation();
3183
3184 // If the call is within a macro, don't do anything (for now).
3185 if (CallLoc.isMacroID())
3186 return nullptr;
3187
3188 assert(AnalysisManager::isInCodeFile(CallLoc, SMgr) &&
3189 "The call piece should not be in a header file.");
3190
3191 // Check if CP represents a path through a function outside of the main file.
3192 if (!AnalysisManager::isInCodeFile(CP->callEnterWithin.asLocation(), SMgr))
3193 return CP;
3194
3195 const PathPieces &Path = CP->path;
3196 if (Path.empty())
3197 return nullptr;
3198
3199 // Check if the last piece in the callee path is a call to a function outside
3200 // of the main file.
3201 if (auto *CPInner = dyn_cast<PathDiagnosticCallPiece>(Path.back().get()))
3202 return getFirstStackedCallToHeaderFile(CPInner, SMgr);
3203
3204 // Otherwise, the last piece is in the main file.
3205 return nullptr;
3206 }
3207
resetDiagnosticLocationToMainFile(PathDiagnostic & PD)3208 static void resetDiagnosticLocationToMainFile(PathDiagnostic &PD) {
3209 if (PD.path.empty())
3210 return;
3211
3212 PathDiagnosticPiece *LastP = PD.path.back().get();
3213 assert(LastP);
3214 const SourceManager &SMgr = LastP->getLocation().getManager();
3215
3216 // We only need to check if the report ends inside headers, if the last piece
3217 // is a call piece.
3218 if (auto *CP = dyn_cast<PathDiagnosticCallPiece>(LastP)) {
3219 CP = getFirstStackedCallToHeaderFile(CP, SMgr);
3220 if (CP) {
3221 // Mark the piece.
3222 CP->setAsLastInMainSourceFile();
3223
3224 // Update the path diagnostic message.
3225 const auto *ND = dyn_cast<NamedDecl>(CP->getCallee());
3226 if (ND) {
3227 SmallString<200> buf;
3228 llvm::raw_svector_ostream os(buf);
3229 os << " (within a call to '" << ND->getDeclName() << "')";
3230 PD.appendToDesc(os.str());
3231 }
3232
3233 // Reset the report containing declaration and location.
3234 PD.setDeclWithIssue(CP->getCaller());
3235 PD.setLocation(CP->getLocation());
3236
3237 return;
3238 }
3239 }
3240 }
3241
3242
3243
3244 std::unique_ptr<DiagnosticForConsumerMapTy>
generateDiagnosticForConsumerMap(BugReport * exampleReport,ArrayRef<PathDiagnosticConsumer * > consumers,ArrayRef<BugReport * > bugReports)3245 PathSensitiveBugReporter::generateDiagnosticForConsumerMap(
3246 BugReport *exampleReport, ArrayRef<PathDiagnosticConsumer *> consumers,
3247 ArrayRef<BugReport *> bugReports) {
3248 std::vector<BasicBugReport *> BasicBugReports;
3249 std::vector<PathSensitiveBugReport *> PathSensitiveBugReports;
3250 if (isa<BasicBugReport>(exampleReport))
3251 return BugReporter::generateDiagnosticForConsumerMap(exampleReport,
3252 consumers, bugReports);
3253
3254 // Generate the full path sensitive diagnostic, using the generation scheme
3255 // specified by the PathDiagnosticConsumer. Note that we have to generate
3256 // path diagnostics even for consumers which do not support paths, because
3257 // the BugReporterVisitors may mark this bug as a false positive.
3258 assert(!bugReports.empty());
3259 MaxBugClassSize.updateMax(bugReports.size());
3260
3261 // Avoid copying the whole array because there may be a lot of reports.
3262 ArrayRef<PathSensitiveBugReport *> convertedArrayOfReports(
3263 reinterpret_cast<PathSensitiveBugReport *const *>(&*bugReports.begin()),
3264 reinterpret_cast<PathSensitiveBugReport *const *>(&*bugReports.end()));
3265 std::unique_ptr<DiagnosticForConsumerMapTy> Out = generatePathDiagnostics(
3266 consumers, convertedArrayOfReports);
3267
3268 if (Out->empty())
3269 return Out;
3270
3271 MaxValidBugClassSize.updateMax(bugReports.size());
3272
3273 // Examine the report and see if the last piece is in a header. Reset the
3274 // report location to the last piece in the main source file.
3275 const AnalyzerOptions &Opts = getAnalyzerOptions();
3276 for (auto const &P : *Out)
3277 if (Opts.ShouldReportIssuesInMainSourceFile && !Opts.AnalyzeAll)
3278 resetDiagnosticLocationToMainFile(*P.second);
3279
3280 return Out;
3281 }
3282
EmitBasicReport(const Decl * DeclWithIssue,const CheckerBase * Checker,StringRef Name,StringRef Category,StringRef Str,PathDiagnosticLocation Loc,ArrayRef<SourceRange> Ranges,ArrayRef<FixItHint> Fixits)3283 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue,
3284 const CheckerBase *Checker, StringRef Name,
3285 StringRef Category, StringRef Str,
3286 PathDiagnosticLocation Loc,
3287 ArrayRef<SourceRange> Ranges,
3288 ArrayRef<FixItHint> Fixits) {
3289 EmitBasicReport(DeclWithIssue, Checker->getCheckerName(), Name, Category, Str,
3290 Loc, Ranges, Fixits);
3291 }
3292
EmitBasicReport(const Decl * DeclWithIssue,CheckerNameRef CheckName,StringRef name,StringRef category,StringRef str,PathDiagnosticLocation Loc,ArrayRef<SourceRange> Ranges,ArrayRef<FixItHint> Fixits)3293 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue,
3294 CheckerNameRef CheckName,
3295 StringRef name, StringRef category,
3296 StringRef str, PathDiagnosticLocation Loc,
3297 ArrayRef<SourceRange> Ranges,
3298 ArrayRef<FixItHint> Fixits) {
3299 // 'BT' is owned by BugReporter.
3300 BugType *BT = getBugTypeForName(CheckName, name, category);
3301 auto R = std::make_unique<BasicBugReport>(*BT, str, Loc);
3302 R->setDeclWithIssue(DeclWithIssue);
3303 for (const auto &SR : Ranges)
3304 R->addRange(SR);
3305 for (const auto &FH : Fixits)
3306 R->addFixItHint(FH);
3307 emitReport(std::move(R));
3308 }
3309
getBugTypeForName(CheckerNameRef CheckName,StringRef name,StringRef category)3310 BugType *BugReporter::getBugTypeForName(CheckerNameRef CheckName,
3311 StringRef name, StringRef category) {
3312 SmallString<136> fullDesc;
3313 llvm::raw_svector_ostream(fullDesc) << CheckName.getName() << ":" << name
3314 << ":" << category;
3315 std::unique_ptr<BugType> &BT = StrBugTypes[fullDesc];
3316 if (!BT)
3317 BT = std::make_unique<BugType>(CheckName, name, category);
3318 return BT.get();
3319 }
3320