1 // BugReporter.cpp - Generate PathDiagnostics for Bugs ------------*- C++ -*--// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines BugReporter, a utility class for generating 11 // PathDiagnostics. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h" 16 #include "clang/AST/ASTContext.h" 17 #include "clang/AST/DeclObjC.h" 18 #include "clang/AST/Expr.h" 19 #include "clang/AST/ExprCXX.h" 20 #include "clang/AST/ParentMap.h" 21 #include "clang/AST/StmtCXX.h" 22 #include "clang/AST/StmtObjC.h" 23 #include "clang/Analysis/CFG.h" 24 #include "clang/Analysis/ProgramPoint.h" 25 #include "clang/Basic/SourceManager.h" 26 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 27 #include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 28 #include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 29 #include "llvm/ADT/DenseMap.h" 30 #include "llvm/ADT/IntrusiveRefCntPtr.h" 31 #include "llvm/ADT/STLExtras.h" 32 #include "llvm/ADT/SmallString.h" 33 #include "llvm/ADT/Statistic.h" 34 #include "llvm/Support/raw_ostream.h" 35 #include <memory> 36 #include <queue> 37 38 using namespace clang; 39 using namespace ento; 40 41 #define DEBUG_TYPE "BugReporter" 42 43 STATISTIC(MaxBugClassSize, 44 "The maximum number of bug reports in the same equivalence class"); 45 STATISTIC(MaxValidBugClassSize, 46 "The maximum number of bug reports in the same equivalence class " 47 "where at least one report is valid (not suppressed)"); 48 49 BugReporterVisitor::~BugReporterVisitor() {} 50 51 void BugReporterContext::anchor() {} 52 53 //===----------------------------------------------------------------------===// 54 // Helper routines for walking the ExplodedGraph and fetching statements. 55 //===----------------------------------------------------------------------===// 56 57 static const Stmt *GetPreviousStmt(const ExplodedNode *N) { 58 for (N = N->getFirstPred(); N; N = N->getFirstPred()) 59 if (const Stmt *S = PathDiagnosticLocation::getStmt(N)) 60 return S; 61 62 return nullptr; 63 } 64 65 static inline const Stmt* 66 GetCurrentOrPreviousStmt(const ExplodedNode *N) { 67 if (const Stmt *S = PathDiagnosticLocation::getStmt(N)) 68 return S; 69 70 return GetPreviousStmt(N); 71 } 72 73 //===----------------------------------------------------------------------===// 74 // Diagnostic cleanup. 75 //===----------------------------------------------------------------------===// 76 77 static PathDiagnosticEventPiece * 78 eventsDescribeSameCondition(PathDiagnosticEventPiece *X, 79 PathDiagnosticEventPiece *Y) { 80 // Prefer diagnostics that come from ConditionBRVisitor over 81 // those that came from TrackConstraintBRVisitor. 82 const void *tagPreferred = ConditionBRVisitor::getTag(); 83 const void *tagLesser = TrackConstraintBRVisitor::getTag(); 84 85 if (X->getLocation() != Y->getLocation()) 86 return nullptr; 87 88 if (X->getTag() == tagPreferred && Y->getTag() == tagLesser) 89 return X; 90 91 if (Y->getTag() == tagPreferred && X->getTag() == tagLesser) 92 return Y; 93 94 return nullptr; 95 } 96 97 /// An optimization pass over PathPieces that removes redundant diagnostics 98 /// generated by both ConditionBRVisitor and TrackConstraintBRVisitor. Both 99 /// BugReporterVisitors use different methods to generate diagnostics, with 100 /// one capable of emitting diagnostics in some cases but not in others. This 101 /// can lead to redundant diagnostic pieces at the same point in a path. 102 static void removeRedundantMsgs(PathPieces &path) { 103 unsigned N = path.size(); 104 if (N < 2) 105 return; 106 // NOTE: this loop intentionally is not using an iterator. Instead, we 107 // are streaming the path and modifying it in place. This is done by 108 // grabbing the front, processing it, and if we decide to keep it append 109 // it to the end of the path. The entire path is processed in this way. 110 for (unsigned i = 0; i < N; ++i) { 111 IntrusiveRefCntPtr<PathDiagnosticPiece> piece(path.front()); 112 path.pop_front(); 113 114 switch (piece->getKind()) { 115 case clang::ento::PathDiagnosticPiece::Call: 116 removeRedundantMsgs(cast<PathDiagnosticCallPiece>(piece)->path); 117 break; 118 case clang::ento::PathDiagnosticPiece::Macro: 119 removeRedundantMsgs(cast<PathDiagnosticMacroPiece>(piece)->subPieces); 120 break; 121 case clang::ento::PathDiagnosticPiece::ControlFlow: 122 break; 123 case clang::ento::PathDiagnosticPiece::Event: { 124 if (i == N-1) 125 break; 126 127 if (PathDiagnosticEventPiece *nextEvent = 128 dyn_cast<PathDiagnosticEventPiece>(path.front().get())) { 129 PathDiagnosticEventPiece *event = 130 cast<PathDiagnosticEventPiece>(piece); 131 // Check to see if we should keep one of the two pieces. If we 132 // come up with a preference, record which piece to keep, and consume 133 // another piece from the path. 134 if (PathDiagnosticEventPiece *pieceToKeep = 135 eventsDescribeSameCondition(event, nextEvent)) { 136 piece = pieceToKeep; 137 path.pop_front(); 138 ++i; 139 } 140 } 141 break; 142 } 143 } 144 path.push_back(piece); 145 } 146 } 147 148 /// A map from PathDiagnosticPiece to the LocationContext of the inlined 149 /// function call it represents. 150 typedef llvm::DenseMap<const PathPieces *, const LocationContext *> 151 LocationContextMap; 152 153 /// Recursively scan through a path and prune out calls and macros pieces 154 /// that aren't needed. Return true if afterwards the path contains 155 /// "interesting stuff" which means it shouldn't be pruned from the parent path. 156 static bool removeUnneededCalls(PathPieces &pieces, BugReport *R, 157 LocationContextMap &LCM) { 158 bool containsSomethingInteresting = false; 159 const unsigned N = pieces.size(); 160 161 for (unsigned i = 0 ; i < N ; ++i) { 162 // Remove the front piece from the path. If it is still something we 163 // want to keep once we are done, we will push it back on the end. 164 IntrusiveRefCntPtr<PathDiagnosticPiece> piece(pieces.front()); 165 pieces.pop_front(); 166 167 switch (piece->getKind()) { 168 case PathDiagnosticPiece::Call: { 169 PathDiagnosticCallPiece *call = cast<PathDiagnosticCallPiece>(piece); 170 // Check if the location context is interesting. 171 assert(LCM.count(&call->path)); 172 if (R->isInteresting(LCM[&call->path])) { 173 containsSomethingInteresting = true; 174 break; 175 } 176 177 if (!removeUnneededCalls(call->path, R, LCM)) 178 continue; 179 180 containsSomethingInteresting = true; 181 break; 182 } 183 case PathDiagnosticPiece::Macro: { 184 PathDiagnosticMacroPiece *macro = cast<PathDiagnosticMacroPiece>(piece); 185 if (!removeUnneededCalls(macro->subPieces, R, LCM)) 186 continue; 187 containsSomethingInteresting = true; 188 break; 189 } 190 case PathDiagnosticPiece::Event: { 191 PathDiagnosticEventPiece *event = cast<PathDiagnosticEventPiece>(piece); 192 193 // We never throw away an event, but we do throw it away wholesale 194 // as part of a path if we throw the entire path away. 195 containsSomethingInteresting |= !event->isPrunable(); 196 break; 197 } 198 case PathDiagnosticPiece::ControlFlow: 199 break; 200 } 201 202 pieces.push_back(piece); 203 } 204 205 return containsSomethingInteresting; 206 } 207 208 /// Returns true if the given decl has been implicitly given a body, either by 209 /// the analyzer or by the compiler proper. 210 static bool hasImplicitBody(const Decl *D) { 211 assert(D); 212 return D->isImplicit() || !D->hasBody(); 213 } 214 215 /// Recursively scan through a path and make sure that all call pieces have 216 /// valid locations. 217 static void 218 adjustCallLocations(PathPieces &Pieces, 219 PathDiagnosticLocation *LastCallLocation = nullptr) { 220 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E; ++I) { 221 PathDiagnosticCallPiece *Call = dyn_cast<PathDiagnosticCallPiece>(*I); 222 223 if (!Call) { 224 assert((*I)->getLocation().asLocation().isValid()); 225 continue; 226 } 227 228 if (LastCallLocation) { 229 bool CallerIsImplicit = hasImplicitBody(Call->getCaller()); 230 if (CallerIsImplicit || !Call->callEnter.asLocation().isValid()) 231 Call->callEnter = *LastCallLocation; 232 if (CallerIsImplicit || !Call->callReturn.asLocation().isValid()) 233 Call->callReturn = *LastCallLocation; 234 } 235 236 // Recursively clean out the subclass. Keep this call around if 237 // it contains any informative diagnostics. 238 PathDiagnosticLocation *ThisCallLocation; 239 if (Call->callEnterWithin.asLocation().isValid() && 240 !hasImplicitBody(Call->getCallee())) 241 ThisCallLocation = &Call->callEnterWithin; 242 else 243 ThisCallLocation = &Call->callEnter; 244 245 assert(ThisCallLocation && "Outermost call has an invalid location"); 246 adjustCallLocations(Call->path, ThisCallLocation); 247 } 248 } 249 250 /// Remove edges in and out of C++ default initializer expressions. These are 251 /// for fields that have in-class initializers, as opposed to being initialized 252 /// explicitly in a constructor or braced list. 253 static void removeEdgesToDefaultInitializers(PathPieces &Pieces) { 254 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) { 255 if (PathDiagnosticCallPiece *C = dyn_cast<PathDiagnosticCallPiece>(*I)) 256 removeEdgesToDefaultInitializers(C->path); 257 258 if (PathDiagnosticMacroPiece *M = dyn_cast<PathDiagnosticMacroPiece>(*I)) 259 removeEdgesToDefaultInitializers(M->subPieces); 260 261 if (PathDiagnosticControlFlowPiece *CF = 262 dyn_cast<PathDiagnosticControlFlowPiece>(*I)) { 263 const Stmt *Start = CF->getStartLocation().asStmt(); 264 const Stmt *End = CF->getEndLocation().asStmt(); 265 if (Start && isa<CXXDefaultInitExpr>(Start)) { 266 I = Pieces.erase(I); 267 continue; 268 } else if (End && isa<CXXDefaultInitExpr>(End)) { 269 PathPieces::iterator Next = std::next(I); 270 if (Next != E) { 271 if (PathDiagnosticControlFlowPiece *NextCF = 272 dyn_cast<PathDiagnosticControlFlowPiece>(*Next)) { 273 NextCF->setStartLocation(CF->getStartLocation()); 274 } 275 } 276 I = Pieces.erase(I); 277 continue; 278 } 279 } 280 281 I++; 282 } 283 } 284 285 /// Remove all pieces with invalid locations as these cannot be serialized. 286 /// We might have pieces with invalid locations as a result of inlining Body 287 /// Farm generated functions. 288 static void removePiecesWithInvalidLocations(PathPieces &Pieces) { 289 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) { 290 if (PathDiagnosticCallPiece *C = dyn_cast<PathDiagnosticCallPiece>(*I)) 291 removePiecesWithInvalidLocations(C->path); 292 293 if (PathDiagnosticMacroPiece *M = dyn_cast<PathDiagnosticMacroPiece>(*I)) 294 removePiecesWithInvalidLocations(M->subPieces); 295 296 if (!(*I)->getLocation().isValid() || 297 !(*I)->getLocation().asLocation().isValid()) { 298 I = Pieces.erase(I); 299 continue; 300 } 301 I++; 302 } 303 } 304 305 //===----------------------------------------------------------------------===// 306 // PathDiagnosticBuilder and its associated routines and helper objects. 307 //===----------------------------------------------------------------------===// 308 309 namespace { 310 class NodeMapClosure : public BugReport::NodeResolver { 311 InterExplodedGraphMap &M; 312 public: 313 NodeMapClosure(InterExplodedGraphMap &m) : M(m) {} 314 315 const ExplodedNode *getOriginalNode(const ExplodedNode *N) override { 316 return M.lookup(N); 317 } 318 }; 319 320 class PathDiagnosticBuilder : public BugReporterContext { 321 BugReport *R; 322 PathDiagnosticConsumer *PDC; 323 NodeMapClosure NMC; 324 public: 325 const LocationContext *LC; 326 327 PathDiagnosticBuilder(GRBugReporter &br, 328 BugReport *r, InterExplodedGraphMap &Backmap, 329 PathDiagnosticConsumer *pdc) 330 : BugReporterContext(br), 331 R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext()) 332 {} 333 334 PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N); 335 336 PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os, 337 const ExplodedNode *N); 338 339 BugReport *getBugReport() { return R; } 340 341 Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); } 342 343 ParentMap& getParentMap() { return LC->getParentMap(); } 344 345 const Stmt *getParent(const Stmt *S) { 346 return getParentMap().getParent(S); 347 } 348 349 NodeMapClosure& getNodeResolver() override { return NMC; } 350 351 PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S); 352 353 PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const { 354 return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive; 355 } 356 357 bool supportsLogicalOpControlFlow() const { 358 return PDC ? PDC->supportsLogicalOpControlFlow() : true; 359 } 360 }; 361 } // end anonymous namespace 362 363 PathDiagnosticLocation 364 PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) { 365 if (const Stmt *S = PathDiagnosticLocation::getNextStmt(N)) 366 return PathDiagnosticLocation(S, getSourceManager(), LC); 367 368 return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(), 369 getSourceManager()); 370 } 371 372 PathDiagnosticLocation 373 PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os, 374 const ExplodedNode *N) { 375 376 // Slow, but probably doesn't matter. 377 if (os.str().empty()) 378 os << ' '; 379 380 const PathDiagnosticLocation &Loc = ExecutionContinues(N); 381 382 if (Loc.asStmt()) 383 os << "Execution continues on line " 384 << getSourceManager().getExpansionLineNumber(Loc.asLocation()) 385 << '.'; 386 else { 387 os << "Execution jumps to the end of the "; 388 const Decl *D = N->getLocationContext()->getDecl(); 389 if (isa<ObjCMethodDecl>(D)) 390 os << "method"; 391 else if (isa<FunctionDecl>(D)) 392 os << "function"; 393 else { 394 assert(isa<BlockDecl>(D)); 395 os << "anonymous block"; 396 } 397 os << '.'; 398 } 399 400 return Loc; 401 } 402 403 static const Stmt *getEnclosingParent(const Stmt *S, const ParentMap &PM) { 404 if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S))) 405 return PM.getParentIgnoreParens(S); 406 407 const Stmt *Parent = PM.getParentIgnoreParens(S); 408 if (!Parent) 409 return nullptr; 410 411 switch (Parent->getStmtClass()) { 412 case Stmt::ForStmtClass: 413 case Stmt::DoStmtClass: 414 case Stmt::WhileStmtClass: 415 case Stmt::ObjCForCollectionStmtClass: 416 case Stmt::CXXForRangeStmtClass: 417 return Parent; 418 default: 419 break; 420 } 421 422 return nullptr; 423 } 424 425 static PathDiagnosticLocation 426 getEnclosingStmtLocation(const Stmt *S, SourceManager &SMgr, const ParentMap &P, 427 const LocationContext *LC, bool allowNestedContexts) { 428 if (!S) 429 return PathDiagnosticLocation(); 430 431 while (const Stmt *Parent = getEnclosingParent(S, P)) { 432 switch (Parent->getStmtClass()) { 433 case Stmt::BinaryOperatorClass: { 434 const BinaryOperator *B = cast<BinaryOperator>(Parent); 435 if (B->isLogicalOp()) 436 return PathDiagnosticLocation(allowNestedContexts ? B : S, SMgr, LC); 437 break; 438 } 439 case Stmt::CompoundStmtClass: 440 case Stmt::StmtExprClass: 441 return PathDiagnosticLocation(S, SMgr, LC); 442 case Stmt::ChooseExprClass: 443 // Similar to '?' if we are referring to condition, just have the edge 444 // point to the entire choose expression. 445 if (allowNestedContexts || cast<ChooseExpr>(Parent)->getCond() == S) 446 return PathDiagnosticLocation(Parent, SMgr, LC); 447 else 448 return PathDiagnosticLocation(S, SMgr, LC); 449 case Stmt::BinaryConditionalOperatorClass: 450 case Stmt::ConditionalOperatorClass: 451 // For '?', if we are referring to condition, just have the edge point 452 // to the entire '?' expression. 453 if (allowNestedContexts || 454 cast<AbstractConditionalOperator>(Parent)->getCond() == S) 455 return PathDiagnosticLocation(Parent, SMgr, LC); 456 else 457 return PathDiagnosticLocation(S, SMgr, LC); 458 case Stmt::CXXForRangeStmtClass: 459 if (cast<CXXForRangeStmt>(Parent)->getBody() == S) 460 return PathDiagnosticLocation(S, SMgr, LC); 461 break; 462 case Stmt::DoStmtClass: 463 return PathDiagnosticLocation(S, SMgr, LC); 464 case Stmt::ForStmtClass: 465 if (cast<ForStmt>(Parent)->getBody() == S) 466 return PathDiagnosticLocation(S, SMgr, LC); 467 break; 468 case Stmt::IfStmtClass: 469 if (cast<IfStmt>(Parent)->getCond() != S) 470 return PathDiagnosticLocation(S, SMgr, LC); 471 break; 472 case Stmt::ObjCForCollectionStmtClass: 473 if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S) 474 return PathDiagnosticLocation(S, SMgr, LC); 475 break; 476 case Stmt::WhileStmtClass: 477 if (cast<WhileStmt>(Parent)->getCond() != S) 478 return PathDiagnosticLocation(S, SMgr, LC); 479 break; 480 default: 481 break; 482 } 483 484 S = Parent; 485 } 486 487 assert(S && "Cannot have null Stmt for PathDiagnosticLocation"); 488 489 return PathDiagnosticLocation(S, SMgr, LC); 490 } 491 492 PathDiagnosticLocation 493 PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) { 494 assert(S && "Null Stmt passed to getEnclosingStmtLocation"); 495 return ::getEnclosingStmtLocation(S, getSourceManager(), getParentMap(), LC, 496 /*allowNestedContexts=*/false); 497 } 498 499 //===----------------------------------------------------------------------===// 500 // "Visitors only" path diagnostic generation algorithm. 501 //===----------------------------------------------------------------------===// 502 static bool GenerateVisitorsOnlyPathDiagnostic( 503 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N, 504 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) { 505 // All path generation skips the very first node (the error node). 506 // This is because there is special handling for the end-of-path note. 507 N = N->getFirstPred(); 508 if (!N) 509 return true; 510 511 BugReport *R = PDB.getBugReport(); 512 while (const ExplodedNode *Pred = N->getFirstPred()) { 513 for (auto &V : visitors) { 514 // Visit all the node pairs, but throw the path pieces away. 515 PathDiagnosticPiece *Piece = V->VisitNode(N, Pred, PDB, *R); 516 delete Piece; 517 } 518 519 N = Pred; 520 } 521 522 return R->isValid(); 523 } 524 525 //===----------------------------------------------------------------------===// 526 // "Minimal" path diagnostic generation algorithm. 527 //===----------------------------------------------------------------------===// 528 typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair; 529 typedef SmallVector<StackDiagPair, 6> StackDiagVector; 530 531 static void updateStackPiecesWithMessage(PathDiagnosticPiece *P, 532 StackDiagVector &CallStack) { 533 // If the piece contains a special message, add it to all the call 534 // pieces on the active stack. 535 if (PathDiagnosticEventPiece *ep = 536 dyn_cast<PathDiagnosticEventPiece>(P)) { 537 538 if (ep->hasCallStackHint()) 539 for (StackDiagVector::iterator I = CallStack.begin(), 540 E = CallStack.end(); I != E; ++I) { 541 PathDiagnosticCallPiece *CP = I->first; 542 const ExplodedNode *N = I->second; 543 std::string stackMsg = ep->getCallStackMessage(N); 544 545 // The last message on the path to final bug is the most important 546 // one. Since we traverse the path backwards, do not add the message 547 // if one has been previously added. 548 if (!CP->hasCallStackMessage()) 549 CP->setCallStackMessage(stackMsg); 550 } 551 } 552 } 553 554 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM); 555 556 static bool GenerateMinimalPathDiagnostic( 557 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N, 558 LocationContextMap &LCM, 559 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) { 560 561 SourceManager& SMgr = PDB.getSourceManager(); 562 const LocationContext *LC = PDB.LC; 563 const ExplodedNode *NextNode = N->pred_empty() 564 ? nullptr : *(N->pred_begin()); 565 566 StackDiagVector CallStack; 567 568 while (NextNode) { 569 N = NextNode; 570 PDB.LC = N->getLocationContext(); 571 NextNode = N->getFirstPred(); 572 573 ProgramPoint P = N->getLocation(); 574 575 do { 576 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 577 PathDiagnosticCallPiece *C = 578 PathDiagnosticCallPiece::construct(N, *CE, SMgr); 579 // Record the mapping from call piece to LocationContext. 580 LCM[&C->path] = CE->getCalleeContext(); 581 PD.getActivePath().push_front(C); 582 PD.pushActivePath(&C->path); 583 CallStack.push_back(StackDiagPair(C, N)); 584 break; 585 } 586 587 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 588 // Flush all locations, and pop the active path. 589 bool VisitedEntireCall = PD.isWithinCall(); 590 PD.popActivePath(); 591 592 // Either we just added a bunch of stuff to the top-level path, or 593 // we have a previous CallExitEnd. If the former, it means that the 594 // path terminated within a function call. We must then take the 595 // current contents of the active path and place it within 596 // a new PathDiagnosticCallPiece. 597 PathDiagnosticCallPiece *C; 598 if (VisitedEntireCall) { 599 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 600 } else { 601 const Decl *Caller = CE->getLocationContext()->getDecl(); 602 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 603 // Record the mapping from call piece to LocationContext. 604 LCM[&C->path] = CE->getCalleeContext(); 605 } 606 607 C->setCallee(*CE, SMgr); 608 if (!CallStack.empty()) { 609 assert(CallStack.back().first == C); 610 CallStack.pop_back(); 611 } 612 break; 613 } 614 615 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 616 const CFGBlock *Src = BE->getSrc(); 617 const CFGBlock *Dst = BE->getDst(); 618 const Stmt *T = Src->getTerminator(); 619 620 if (!T) 621 break; 622 623 PathDiagnosticLocation Start = 624 PathDiagnosticLocation::createBegin(T, SMgr, 625 N->getLocationContext()); 626 627 switch (T->getStmtClass()) { 628 default: 629 break; 630 631 case Stmt::GotoStmtClass: 632 case Stmt::IndirectGotoStmtClass: { 633 const Stmt *S = PathDiagnosticLocation::getNextStmt(N); 634 635 if (!S) 636 break; 637 638 std::string sbuf; 639 llvm::raw_string_ostream os(sbuf); 640 const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S); 641 642 os << "Control jumps to line " 643 << End.asLocation().getExpansionLineNumber(); 644 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 645 Start, End, os.str())); 646 break; 647 } 648 649 case Stmt::SwitchStmtClass: { 650 // Figure out what case arm we took. 651 std::string sbuf; 652 llvm::raw_string_ostream os(sbuf); 653 654 if (const Stmt *S = Dst->getLabel()) { 655 PathDiagnosticLocation End(S, SMgr, LC); 656 657 switch (S->getStmtClass()) { 658 default: 659 os << "No cases match in the switch statement. " 660 "Control jumps to line " 661 << End.asLocation().getExpansionLineNumber(); 662 break; 663 case Stmt::DefaultStmtClass: 664 os << "Control jumps to the 'default' case at line " 665 << End.asLocation().getExpansionLineNumber(); 666 break; 667 668 case Stmt::CaseStmtClass: { 669 os << "Control jumps to 'case "; 670 const CaseStmt *Case = cast<CaseStmt>(S); 671 const Expr *LHS = Case->getLHS()->IgnoreParenCasts(); 672 673 // Determine if it is an enum. 674 bool GetRawInt = true; 675 676 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) { 677 // FIXME: Maybe this should be an assertion. Are there cases 678 // were it is not an EnumConstantDecl? 679 const EnumConstantDecl *D = 680 dyn_cast<EnumConstantDecl>(DR->getDecl()); 681 682 if (D) { 683 GetRawInt = false; 684 os << *D; 685 } 686 } 687 688 if (GetRawInt) 689 os << LHS->EvaluateKnownConstInt(PDB.getASTContext()); 690 691 os << ":' at line " 692 << End.asLocation().getExpansionLineNumber(); 693 break; 694 } 695 } 696 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 697 Start, End, os.str())); 698 } 699 else { 700 os << "'Default' branch taken. "; 701 const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N); 702 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 703 Start, End, os.str())); 704 } 705 706 break; 707 } 708 709 case Stmt::BreakStmtClass: 710 case Stmt::ContinueStmtClass: { 711 std::string sbuf; 712 llvm::raw_string_ostream os(sbuf); 713 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 714 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 715 Start, End, os.str())); 716 break; 717 } 718 719 // Determine control-flow for ternary '?'. 720 case Stmt::BinaryConditionalOperatorClass: 721 case Stmt::ConditionalOperatorClass: { 722 std::string sbuf; 723 llvm::raw_string_ostream os(sbuf); 724 os << "'?' condition is "; 725 726 if (*(Src->succ_begin()+1) == Dst) 727 os << "false"; 728 else 729 os << "true"; 730 731 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 732 733 if (const Stmt *S = End.asStmt()) 734 End = PDB.getEnclosingStmtLocation(S); 735 736 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 737 Start, End, os.str())); 738 break; 739 } 740 741 // Determine control-flow for short-circuited '&&' and '||'. 742 case Stmt::BinaryOperatorClass: { 743 if (!PDB.supportsLogicalOpControlFlow()) 744 break; 745 746 const BinaryOperator *B = cast<BinaryOperator>(T); 747 std::string sbuf; 748 llvm::raw_string_ostream os(sbuf); 749 os << "Left side of '"; 750 751 if (B->getOpcode() == BO_LAnd) { 752 os << "&&" << "' is "; 753 754 if (*(Src->succ_begin()+1) == Dst) { 755 os << "false"; 756 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 757 PathDiagnosticLocation Start = 758 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 759 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 760 Start, End, os.str())); 761 } 762 else { 763 os << "true"; 764 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 765 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 766 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 767 Start, End, os.str())); 768 } 769 } 770 else { 771 assert(B->getOpcode() == BO_LOr); 772 os << "||" << "' is "; 773 774 if (*(Src->succ_begin()+1) == Dst) { 775 os << "false"; 776 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 777 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 778 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 779 Start, End, os.str())); 780 } 781 else { 782 os << "true"; 783 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 784 PathDiagnosticLocation Start = 785 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 786 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 787 Start, End, os.str())); 788 } 789 } 790 791 break; 792 } 793 794 case Stmt::DoStmtClass: { 795 if (*(Src->succ_begin()) == Dst) { 796 std::string sbuf; 797 llvm::raw_string_ostream os(sbuf); 798 799 os << "Loop condition is true. "; 800 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 801 802 if (const Stmt *S = End.asStmt()) 803 End = PDB.getEnclosingStmtLocation(S); 804 805 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 806 Start, End, os.str())); 807 } 808 else { 809 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 810 811 if (const Stmt *S = End.asStmt()) 812 End = PDB.getEnclosingStmtLocation(S); 813 814 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 815 Start, End, "Loop condition is false. Exiting loop")); 816 } 817 818 break; 819 } 820 821 case Stmt::WhileStmtClass: 822 case Stmt::ForStmtClass: { 823 if (*(Src->succ_begin()+1) == Dst) { 824 std::string sbuf; 825 llvm::raw_string_ostream os(sbuf); 826 827 os << "Loop condition is false. "; 828 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 829 if (const Stmt *S = End.asStmt()) 830 End = PDB.getEnclosingStmtLocation(S); 831 832 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 833 Start, End, os.str())); 834 } 835 else { 836 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 837 if (const Stmt *S = End.asStmt()) 838 End = PDB.getEnclosingStmtLocation(S); 839 840 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 841 Start, End, "Loop condition is true. Entering loop body")); 842 } 843 844 break; 845 } 846 847 case Stmt::IfStmtClass: { 848 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 849 850 if (const Stmt *S = End.asStmt()) 851 End = PDB.getEnclosingStmtLocation(S); 852 853 if (*(Src->succ_begin()+1) == Dst) 854 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 855 Start, End, "Taking false branch")); 856 else 857 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 858 Start, End, "Taking true branch")); 859 860 break; 861 } 862 } 863 } 864 } while(0); 865 866 if (NextNode) { 867 // Add diagnostic pieces from custom visitors. 868 BugReport *R = PDB.getBugReport(); 869 for (auto &V : visitors) { 870 if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *R)) { 871 PD.getActivePath().push_front(p); 872 updateStackPiecesWithMessage(p, CallStack); 873 } 874 } 875 } 876 } 877 878 if (!PDB.getBugReport()->isValid()) 879 return false; 880 881 // After constructing the full PathDiagnostic, do a pass over it to compact 882 // PathDiagnosticPieces that occur within a macro. 883 CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager()); 884 return true; 885 } 886 887 //===----------------------------------------------------------------------===// 888 // "Extensive" PathDiagnostic generation. 889 //===----------------------------------------------------------------------===// 890 891 static bool IsControlFlowExpr(const Stmt *S) { 892 const Expr *E = dyn_cast<Expr>(S); 893 894 if (!E) 895 return false; 896 897 E = E->IgnoreParenCasts(); 898 899 if (isa<AbstractConditionalOperator>(E)) 900 return true; 901 902 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E)) 903 if (B->isLogicalOp()) 904 return true; 905 906 return false; 907 } 908 909 namespace { 910 class ContextLocation : public PathDiagnosticLocation { 911 bool IsDead; 912 public: 913 ContextLocation(const PathDiagnosticLocation &L, bool isdead = false) 914 : PathDiagnosticLocation(L), IsDead(isdead) {} 915 916 void markDead() { IsDead = true; } 917 bool isDead() const { return IsDead; } 918 }; 919 920 static PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L, 921 const LocationContext *LC, 922 bool firstCharOnly = false) { 923 if (const Stmt *S = L.asStmt()) { 924 const Stmt *Original = S; 925 while (1) { 926 // Adjust the location for some expressions that are best referenced 927 // by one of their subexpressions. 928 switch (S->getStmtClass()) { 929 default: 930 break; 931 case Stmt::ParenExprClass: 932 case Stmt::GenericSelectionExprClass: 933 S = cast<Expr>(S)->IgnoreParens(); 934 firstCharOnly = true; 935 continue; 936 case Stmt::BinaryConditionalOperatorClass: 937 case Stmt::ConditionalOperatorClass: 938 S = cast<AbstractConditionalOperator>(S)->getCond(); 939 firstCharOnly = true; 940 continue; 941 case Stmt::ChooseExprClass: 942 S = cast<ChooseExpr>(S)->getCond(); 943 firstCharOnly = true; 944 continue; 945 case Stmt::BinaryOperatorClass: 946 S = cast<BinaryOperator>(S)->getLHS(); 947 firstCharOnly = true; 948 continue; 949 } 950 951 break; 952 } 953 954 if (S != Original) 955 L = PathDiagnosticLocation(S, L.getManager(), LC); 956 } 957 958 if (firstCharOnly) 959 L = PathDiagnosticLocation::createSingleLocation(L); 960 961 return L; 962 } 963 964 class EdgeBuilder { 965 std::vector<ContextLocation> CLocs; 966 typedef std::vector<ContextLocation>::iterator iterator; 967 PathDiagnostic &PD; 968 PathDiagnosticBuilder &PDB; 969 PathDiagnosticLocation PrevLoc; 970 971 bool IsConsumedExpr(const PathDiagnosticLocation &L); 972 973 bool containsLocation(const PathDiagnosticLocation &Container, 974 const PathDiagnosticLocation &Containee); 975 976 PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L); 977 978 979 980 void popLocation() { 981 if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) { 982 // For contexts, we only one the first character as the range. 983 rawAddEdge(cleanUpLocation(CLocs.back(), PDB.LC, true)); 984 } 985 CLocs.pop_back(); 986 } 987 988 public: 989 EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb) 990 : PD(pd), PDB(pdb) { 991 992 // If the PathDiagnostic already has pieces, add the enclosing statement 993 // of the first piece as a context as well. 994 if (!PD.path.empty()) { 995 PrevLoc = (*PD.path.begin())->getLocation(); 996 997 if (const Stmt *S = PrevLoc.asStmt()) 998 addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 999 } 1000 } 1001 1002 ~EdgeBuilder() { 1003 while (!CLocs.empty()) popLocation(); 1004 1005 // Finally, add an initial edge from the start location of the first 1006 // statement (if it doesn't already exist). 1007 PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin( 1008 PDB.LC, 1009 PDB.getSourceManager()); 1010 if (L.isValid()) 1011 rawAddEdge(L); 1012 } 1013 1014 void flushLocations() { 1015 while (!CLocs.empty()) 1016 popLocation(); 1017 PrevLoc = PathDiagnosticLocation(); 1018 } 1019 1020 void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false, 1021 bool IsPostJump = false); 1022 1023 void rawAddEdge(PathDiagnosticLocation NewLoc); 1024 1025 void addContext(const Stmt *S); 1026 void addContext(const PathDiagnosticLocation &L); 1027 void addExtendedContext(const Stmt *S); 1028 }; 1029 } // end anonymous namespace 1030 1031 1032 PathDiagnosticLocation 1033 EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) { 1034 if (const Stmt *S = L.asStmt()) { 1035 if (IsControlFlowExpr(S)) 1036 return L; 1037 1038 return PDB.getEnclosingStmtLocation(S); 1039 } 1040 1041 return L; 1042 } 1043 1044 bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container, 1045 const PathDiagnosticLocation &Containee) { 1046 1047 if (Container == Containee) 1048 return true; 1049 1050 if (Container.asDecl()) 1051 return true; 1052 1053 if (const Stmt *S = Containee.asStmt()) 1054 if (const Stmt *ContainerS = Container.asStmt()) { 1055 while (S) { 1056 if (S == ContainerS) 1057 return true; 1058 S = PDB.getParent(S); 1059 } 1060 return false; 1061 } 1062 1063 // Less accurate: compare using source ranges. 1064 SourceRange ContainerR = Container.asRange(); 1065 SourceRange ContaineeR = Containee.asRange(); 1066 1067 SourceManager &SM = PDB.getSourceManager(); 1068 SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin()); 1069 SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd()); 1070 SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin()); 1071 SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd()); 1072 1073 unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg); 1074 unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd); 1075 unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg); 1076 unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd); 1077 1078 assert(ContainerBegLine <= ContainerEndLine); 1079 assert(ContaineeBegLine <= ContaineeEndLine); 1080 1081 return (ContainerBegLine <= ContaineeBegLine && 1082 ContainerEndLine >= ContaineeEndLine && 1083 (ContainerBegLine != ContaineeBegLine || 1084 SM.getExpansionColumnNumber(ContainerRBeg) <= 1085 SM.getExpansionColumnNumber(ContaineeRBeg)) && 1086 (ContainerEndLine != ContaineeEndLine || 1087 SM.getExpansionColumnNumber(ContainerREnd) >= 1088 SM.getExpansionColumnNumber(ContaineeREnd))); 1089 } 1090 1091 void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) { 1092 if (!PrevLoc.isValid()) { 1093 PrevLoc = NewLoc; 1094 return; 1095 } 1096 1097 const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc, PDB.LC); 1098 const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc, PDB.LC); 1099 1100 if (PrevLocClean.asLocation().isInvalid()) { 1101 PrevLoc = NewLoc; 1102 return; 1103 } 1104 1105 if (NewLocClean.asLocation() == PrevLocClean.asLocation()) 1106 return; 1107 1108 // FIXME: Ignore intra-macro edges for now. 1109 if (NewLocClean.asLocation().getExpansionLoc() == 1110 PrevLocClean.asLocation().getExpansionLoc()) 1111 return; 1112 1113 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean)); 1114 PrevLoc = NewLoc; 1115 } 1116 1117 void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd, 1118 bool IsPostJump) { 1119 1120 if (!alwaysAdd && NewLoc.asLocation().isMacroID()) 1121 return; 1122 1123 const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc); 1124 1125 while (!CLocs.empty()) { 1126 ContextLocation &TopContextLoc = CLocs.back(); 1127 1128 // Is the top location context the same as the one for the new location? 1129 if (TopContextLoc == CLoc) { 1130 if (alwaysAdd) { 1131 if (IsConsumedExpr(TopContextLoc)) 1132 TopContextLoc.markDead(); 1133 1134 rawAddEdge(NewLoc); 1135 } 1136 1137 if (IsPostJump) 1138 TopContextLoc.markDead(); 1139 return; 1140 } 1141 1142 if (containsLocation(TopContextLoc, CLoc)) { 1143 if (alwaysAdd) { 1144 rawAddEdge(NewLoc); 1145 1146 if (IsConsumedExpr(CLoc)) { 1147 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/true)); 1148 return; 1149 } 1150 } 1151 1152 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/IsPostJump)); 1153 return; 1154 } 1155 1156 // Context does not contain the location. Flush it. 1157 popLocation(); 1158 } 1159 1160 // If we reach here, there is no enclosing context. Just add the edge. 1161 rawAddEdge(NewLoc); 1162 } 1163 1164 bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) { 1165 if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt())) 1166 return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X); 1167 1168 return false; 1169 } 1170 1171 void EdgeBuilder::addExtendedContext(const Stmt *S) { 1172 if (!S) 1173 return; 1174 1175 const Stmt *Parent = PDB.getParent(S); 1176 while (Parent) { 1177 if (isa<CompoundStmt>(Parent)) 1178 Parent = PDB.getParent(Parent); 1179 else 1180 break; 1181 } 1182 1183 if (Parent) { 1184 switch (Parent->getStmtClass()) { 1185 case Stmt::DoStmtClass: 1186 case Stmt::ObjCAtSynchronizedStmtClass: 1187 addContext(Parent); 1188 default: 1189 break; 1190 } 1191 } 1192 1193 addContext(S); 1194 } 1195 1196 void EdgeBuilder::addContext(const Stmt *S) { 1197 if (!S) 1198 return; 1199 1200 PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC); 1201 addContext(L); 1202 } 1203 1204 void EdgeBuilder::addContext(const PathDiagnosticLocation &L) { 1205 while (!CLocs.empty()) { 1206 const PathDiagnosticLocation &TopContextLoc = CLocs.back(); 1207 1208 // Is the top location context the same as the one for the new location? 1209 if (TopContextLoc == L) 1210 return; 1211 1212 if (containsLocation(TopContextLoc, L)) { 1213 CLocs.push_back(L); 1214 return; 1215 } 1216 1217 // Context does not contain the location. Flush it. 1218 popLocation(); 1219 } 1220 1221 CLocs.push_back(L); 1222 } 1223 1224 // Cone-of-influence: support the reverse propagation of "interesting" symbols 1225 // and values by tracing interesting calculations backwards through evaluated 1226 // expressions along a path. This is probably overly complicated, but the idea 1227 // is that if an expression computed an "interesting" value, the child 1228 // expressions are are also likely to be "interesting" as well (which then 1229 // propagates to the values they in turn compute). This reverse propagation 1230 // is needed to track interesting correlations across function call boundaries, 1231 // where formal arguments bind to actual arguments, etc. This is also needed 1232 // because the constraint solver sometimes simplifies certain symbolic values 1233 // into constants when appropriate, and this complicates reasoning about 1234 // interesting values. 1235 typedef llvm::DenseSet<const Expr *> InterestingExprs; 1236 1237 static void reversePropagateIntererstingSymbols(BugReport &R, 1238 InterestingExprs &IE, 1239 const ProgramState *State, 1240 const Expr *Ex, 1241 const LocationContext *LCtx) { 1242 SVal V = State->getSVal(Ex, LCtx); 1243 if (!(R.isInteresting(V) || IE.count(Ex))) 1244 return; 1245 1246 switch (Ex->getStmtClass()) { 1247 default: 1248 if (!isa<CastExpr>(Ex)) 1249 break; 1250 // Fall through. 1251 case Stmt::BinaryOperatorClass: 1252 case Stmt::UnaryOperatorClass: { 1253 for (Stmt::const_child_iterator CI = Ex->child_begin(), 1254 CE = Ex->child_end(); 1255 CI != CE; ++CI) { 1256 if (const Expr *child = dyn_cast_or_null<Expr>(*CI)) { 1257 IE.insert(child); 1258 SVal ChildV = State->getSVal(child, LCtx); 1259 R.markInteresting(ChildV); 1260 } 1261 } 1262 break; 1263 } 1264 } 1265 1266 R.markInteresting(V); 1267 } 1268 1269 static void reversePropagateInterestingSymbols(BugReport &R, 1270 InterestingExprs &IE, 1271 const ProgramState *State, 1272 const LocationContext *CalleeCtx, 1273 const LocationContext *CallerCtx) 1274 { 1275 // FIXME: Handle non-CallExpr-based CallEvents. 1276 const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame(); 1277 const Stmt *CallSite = Callee->getCallSite(); 1278 if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) { 1279 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) { 1280 FunctionDecl::param_const_iterator PI = FD->param_begin(), 1281 PE = FD->param_end(); 1282 CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end(); 1283 for (; AI != AE && PI != PE; ++AI, ++PI) { 1284 if (const Expr *ArgE = *AI) { 1285 if (const ParmVarDecl *PD = *PI) { 1286 Loc LV = State->getLValue(PD, CalleeCtx); 1287 if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV))) 1288 IE.insert(ArgE); 1289 } 1290 } 1291 } 1292 } 1293 } 1294 } 1295 1296 //===----------------------------------------------------------------------===// 1297 // Functions for determining if a loop was executed 0 times. 1298 //===----------------------------------------------------------------------===// 1299 1300 static bool isLoop(const Stmt *Term) { 1301 switch (Term->getStmtClass()) { 1302 case Stmt::ForStmtClass: 1303 case Stmt::WhileStmtClass: 1304 case Stmt::ObjCForCollectionStmtClass: 1305 case Stmt::CXXForRangeStmtClass: 1306 return true; 1307 default: 1308 // Note that we intentionally do not include do..while here. 1309 return false; 1310 } 1311 } 1312 1313 static bool isJumpToFalseBranch(const BlockEdge *BE) { 1314 const CFGBlock *Src = BE->getSrc(); 1315 assert(Src->succ_size() == 2); 1316 return (*(Src->succ_begin()+1) == BE->getDst()); 1317 } 1318 1319 /// Return true if the terminator is a loop and the destination is the 1320 /// false branch. 1321 static bool isLoopJumpPastBody(const Stmt *Term, const BlockEdge *BE) { 1322 if (!isLoop(Term)) 1323 return false; 1324 1325 // Did we take the false branch? 1326 return isJumpToFalseBranch(BE); 1327 } 1328 1329 static bool isContainedByStmt(ParentMap &PM, const Stmt *S, const Stmt *SubS) { 1330 while (SubS) { 1331 if (SubS == S) 1332 return true; 1333 SubS = PM.getParent(SubS); 1334 } 1335 return false; 1336 } 1337 1338 static const Stmt *getStmtBeforeCond(ParentMap &PM, const Stmt *Term, 1339 const ExplodedNode *N) { 1340 while (N) { 1341 Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>(); 1342 if (SP) { 1343 const Stmt *S = SP->getStmt(); 1344 if (!isContainedByStmt(PM, Term, S)) 1345 return S; 1346 } 1347 N = N->getFirstPred(); 1348 } 1349 return nullptr; 1350 } 1351 1352 static bool isInLoopBody(ParentMap &PM, const Stmt *S, const Stmt *Term) { 1353 const Stmt *LoopBody = nullptr; 1354 switch (Term->getStmtClass()) { 1355 case Stmt::CXXForRangeStmtClass: { 1356 const CXXForRangeStmt *FR = cast<CXXForRangeStmt>(Term); 1357 if (isContainedByStmt(PM, FR->getInc(), S)) 1358 return true; 1359 if (isContainedByStmt(PM, FR->getLoopVarStmt(), S)) 1360 return true; 1361 LoopBody = FR->getBody(); 1362 break; 1363 } 1364 case Stmt::ForStmtClass: { 1365 const ForStmt *FS = cast<ForStmt>(Term); 1366 if (isContainedByStmt(PM, FS->getInc(), S)) 1367 return true; 1368 LoopBody = FS->getBody(); 1369 break; 1370 } 1371 case Stmt::ObjCForCollectionStmtClass: { 1372 const ObjCForCollectionStmt *FC = cast<ObjCForCollectionStmt>(Term); 1373 LoopBody = FC->getBody(); 1374 break; 1375 } 1376 case Stmt::WhileStmtClass: 1377 LoopBody = cast<WhileStmt>(Term)->getBody(); 1378 break; 1379 default: 1380 return false; 1381 } 1382 return isContainedByStmt(PM, LoopBody, S); 1383 } 1384 1385 //===----------------------------------------------------------------------===// 1386 // Top-level logic for generating extensive path diagnostics. 1387 //===----------------------------------------------------------------------===// 1388 1389 static bool GenerateExtensivePathDiagnostic( 1390 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N, 1391 LocationContextMap &LCM, 1392 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) { 1393 EdgeBuilder EB(PD, PDB); 1394 const SourceManager& SM = PDB.getSourceManager(); 1395 StackDiagVector CallStack; 1396 InterestingExprs IE; 1397 1398 const ExplodedNode *NextNode = N->pred_empty() ? nullptr : *(N->pred_begin()); 1399 while (NextNode) { 1400 N = NextNode; 1401 NextNode = N->getFirstPred(); 1402 ProgramPoint P = N->getLocation(); 1403 1404 do { 1405 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1406 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1407 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1408 N->getState().get(), Ex, 1409 N->getLocationContext()); 1410 } 1411 1412 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1413 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1414 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1415 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1416 N->getState().get(), Ex, 1417 N->getLocationContext()); 1418 } 1419 1420 PathDiagnosticCallPiece *C = 1421 PathDiagnosticCallPiece::construct(N, *CE, SM); 1422 LCM[&C->path] = CE->getCalleeContext(); 1423 1424 EB.addEdge(C->callReturn, /*AlwaysAdd=*/true, /*IsPostJump=*/true); 1425 EB.flushLocations(); 1426 1427 PD.getActivePath().push_front(C); 1428 PD.pushActivePath(&C->path); 1429 CallStack.push_back(StackDiagPair(C, N)); 1430 break; 1431 } 1432 1433 // Pop the call hierarchy if we are done walking the contents 1434 // of a function call. 1435 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1436 // Add an edge to the start of the function. 1437 const Decl *D = CE->getCalleeContext()->getDecl(); 1438 PathDiagnosticLocation pos = 1439 PathDiagnosticLocation::createBegin(D, SM); 1440 EB.addEdge(pos); 1441 1442 // Flush all locations, and pop the active path. 1443 bool VisitedEntireCall = PD.isWithinCall(); 1444 EB.flushLocations(); 1445 PD.popActivePath(); 1446 PDB.LC = N->getLocationContext(); 1447 1448 // Either we just added a bunch of stuff to the top-level path, or 1449 // we have a previous CallExitEnd. If the former, it means that the 1450 // path terminated within a function call. We must then take the 1451 // current contents of the active path and place it within 1452 // a new PathDiagnosticCallPiece. 1453 PathDiagnosticCallPiece *C; 1454 if (VisitedEntireCall) { 1455 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 1456 } else { 1457 const Decl *Caller = CE->getLocationContext()->getDecl(); 1458 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1459 LCM[&C->path] = CE->getCalleeContext(); 1460 } 1461 1462 C->setCallee(*CE, SM); 1463 EB.addContext(C->getLocation()); 1464 1465 if (!CallStack.empty()) { 1466 assert(CallStack.back().first == C); 1467 CallStack.pop_back(); 1468 } 1469 break; 1470 } 1471 1472 // Note that is important that we update the LocationContext 1473 // after looking at CallExits. CallExit basically adds an 1474 // edge in the *caller*, so we don't want to update the LocationContext 1475 // too soon. 1476 PDB.LC = N->getLocationContext(); 1477 1478 // Block edges. 1479 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1480 // Does this represent entering a call? If so, look at propagating 1481 // interesting symbols across call boundaries. 1482 if (NextNode) { 1483 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1484 const LocationContext *CalleeCtx = PDB.LC; 1485 if (CallerCtx != CalleeCtx) { 1486 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1487 N->getState().get(), 1488 CalleeCtx, CallerCtx); 1489 } 1490 } 1491 1492 // Are we jumping to the head of a loop? Add a special diagnostic. 1493 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1494 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1495 const CompoundStmt *CS = nullptr; 1496 1497 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1498 CS = dyn_cast<CompoundStmt>(FS->getBody()); 1499 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1500 CS = dyn_cast<CompoundStmt>(WS->getBody()); 1501 1502 PathDiagnosticEventPiece *p = 1503 new PathDiagnosticEventPiece(L, 1504 "Looping back to the head of the loop"); 1505 p->setPrunable(true); 1506 1507 EB.addEdge(p->getLocation(), true); 1508 PD.getActivePath().push_front(p); 1509 1510 if (CS) { 1511 PathDiagnosticLocation BL = 1512 PathDiagnosticLocation::createEndBrace(CS, SM); 1513 EB.addEdge(BL); 1514 } 1515 } 1516 1517 const CFGBlock *BSrc = BE->getSrc(); 1518 ParentMap &PM = PDB.getParentMap(); 1519 1520 if (const Stmt *Term = BSrc->getTerminator()) { 1521 // Are we jumping past the loop body without ever executing the 1522 // loop (because the condition was false)? 1523 if (isLoopJumpPastBody(Term, &*BE) && 1524 !isInLoopBody(PM, 1525 getStmtBeforeCond(PM, 1526 BSrc->getTerminatorCondition(), 1527 N), 1528 Term)) { 1529 PathDiagnosticLocation L(Term, SM, PDB.LC); 1530 PathDiagnosticEventPiece *PE = 1531 new PathDiagnosticEventPiece(L, "Loop body executed 0 times"); 1532 PE->setPrunable(true); 1533 1534 EB.addEdge(PE->getLocation(), true); 1535 PD.getActivePath().push_front(PE); 1536 } 1537 1538 // In any case, add the terminator as the current statement 1539 // context for control edges. 1540 EB.addContext(Term); 1541 } 1542 1543 break; 1544 } 1545 1546 if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) { 1547 Optional<CFGElement> First = BE->getFirstElement(); 1548 if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) { 1549 const Stmt *stmt = S->getStmt(); 1550 if (IsControlFlowExpr(stmt)) { 1551 // Add the proper context for '&&', '||', and '?'. 1552 EB.addContext(stmt); 1553 } 1554 else 1555 EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt()); 1556 } 1557 1558 break; 1559 } 1560 1561 1562 } while (0); 1563 1564 if (!NextNode) 1565 continue; 1566 1567 // Add pieces from custom visitors. 1568 BugReport *R = PDB.getBugReport(); 1569 for (auto &V : visitors) { 1570 if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *R)) { 1571 const PathDiagnosticLocation &Loc = p->getLocation(); 1572 EB.addEdge(Loc, true); 1573 PD.getActivePath().push_front(p); 1574 updateStackPiecesWithMessage(p, CallStack); 1575 1576 if (const Stmt *S = Loc.asStmt()) 1577 EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 1578 } 1579 } 1580 } 1581 1582 return PDB.getBugReport()->isValid(); 1583 } 1584 1585 /// \brief Adds a sanitized control-flow diagnostic edge to a path. 1586 static void addEdgeToPath(PathPieces &path, 1587 PathDiagnosticLocation &PrevLoc, 1588 PathDiagnosticLocation NewLoc, 1589 const LocationContext *LC) { 1590 if (!NewLoc.isValid()) 1591 return; 1592 1593 SourceLocation NewLocL = NewLoc.asLocation(); 1594 if (NewLocL.isInvalid()) 1595 return; 1596 1597 if (!PrevLoc.isValid() || !PrevLoc.asLocation().isValid()) { 1598 PrevLoc = NewLoc; 1599 return; 1600 } 1601 1602 // Ignore self-edges, which occur when there are multiple nodes at the same 1603 // statement. 1604 if (NewLoc.asStmt() && NewLoc.asStmt() == PrevLoc.asStmt()) 1605 return; 1606 1607 path.push_front(new PathDiagnosticControlFlowPiece(NewLoc, 1608 PrevLoc)); 1609 PrevLoc = NewLoc; 1610 } 1611 1612 /// A customized wrapper for CFGBlock::getTerminatorCondition() 1613 /// which returns the element for ObjCForCollectionStmts. 1614 static const Stmt *getTerminatorCondition(const CFGBlock *B) { 1615 const Stmt *S = B->getTerminatorCondition(); 1616 if (const ObjCForCollectionStmt *FS = 1617 dyn_cast_or_null<ObjCForCollectionStmt>(S)) 1618 return FS->getElement(); 1619 return S; 1620 } 1621 1622 static const char StrEnteringLoop[] = "Entering loop body"; 1623 static const char StrLoopBodyZero[] = "Loop body executed 0 times"; 1624 static const char StrLoopRangeEmpty[] = 1625 "Loop body skipped when range is empty"; 1626 static const char StrLoopCollectionEmpty[] = 1627 "Loop body skipped when collection is empty"; 1628 1629 static bool GenerateAlternateExtensivePathDiagnostic( 1630 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N, 1631 LocationContextMap &LCM, 1632 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) { 1633 1634 BugReport *report = PDB.getBugReport(); 1635 const SourceManager& SM = PDB.getSourceManager(); 1636 StackDiagVector CallStack; 1637 InterestingExprs IE; 1638 1639 PathDiagnosticLocation PrevLoc = PD.getLocation(); 1640 1641 const ExplodedNode *NextNode = N->getFirstPred(); 1642 while (NextNode) { 1643 N = NextNode; 1644 NextNode = N->getFirstPred(); 1645 ProgramPoint P = N->getLocation(); 1646 1647 do { 1648 // Have we encountered an entrance to a call? It may be 1649 // the case that we have not encountered a matching 1650 // call exit before this point. This means that the path 1651 // terminated within the call itself. 1652 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1653 // Add an edge to the start of the function. 1654 const StackFrameContext *CalleeLC = CE->getCalleeContext(); 1655 const Decl *D = CalleeLC->getDecl(); 1656 addEdgeToPath(PD.getActivePath(), PrevLoc, 1657 PathDiagnosticLocation::createBegin(D, SM), 1658 CalleeLC); 1659 1660 // Did we visit an entire call? 1661 bool VisitedEntireCall = PD.isWithinCall(); 1662 PD.popActivePath(); 1663 1664 PathDiagnosticCallPiece *C; 1665 if (VisitedEntireCall) { 1666 PathDiagnosticPiece *P = PD.getActivePath().front().get(); 1667 C = cast<PathDiagnosticCallPiece>(P); 1668 } else { 1669 const Decl *Caller = CE->getLocationContext()->getDecl(); 1670 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1671 1672 // Since we just transferred the path over to the call piece, 1673 // reset the mapping from active to location context. 1674 assert(PD.getActivePath().size() == 1 && 1675 PD.getActivePath().front() == C); 1676 LCM[&PD.getActivePath()] = nullptr; 1677 1678 // Record the location context mapping for the path within 1679 // the call. 1680 assert(LCM[&C->path] == nullptr || 1681 LCM[&C->path] == CE->getCalleeContext()); 1682 LCM[&C->path] = CE->getCalleeContext(); 1683 1684 // If this is the first item in the active path, record 1685 // the new mapping from active path to location context. 1686 const LocationContext *&NewLC = LCM[&PD.getActivePath()]; 1687 if (!NewLC) 1688 NewLC = N->getLocationContext(); 1689 1690 PDB.LC = NewLC; 1691 } 1692 C->setCallee(*CE, SM); 1693 1694 // Update the previous location in the active path. 1695 PrevLoc = C->getLocation(); 1696 1697 if (!CallStack.empty()) { 1698 assert(CallStack.back().first == C); 1699 CallStack.pop_back(); 1700 } 1701 break; 1702 } 1703 1704 // Query the location context here and the previous location 1705 // as processing CallEnter may change the active path. 1706 PDB.LC = N->getLocationContext(); 1707 1708 // Record the mapping from the active path to the location 1709 // context. 1710 assert(!LCM[&PD.getActivePath()] || 1711 LCM[&PD.getActivePath()] == PDB.LC); 1712 LCM[&PD.getActivePath()] = PDB.LC; 1713 1714 // Have we encountered an exit from a function call? 1715 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1716 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1717 // Propagate the interesting symbols accordingly. 1718 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1719 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1720 N->getState().get(), Ex, 1721 N->getLocationContext()); 1722 } 1723 1724 // We are descending into a call (backwards). Construct 1725 // a new call piece to contain the path pieces for that call. 1726 PathDiagnosticCallPiece *C = 1727 PathDiagnosticCallPiece::construct(N, *CE, SM); 1728 1729 // Record the location context for this call piece. 1730 LCM[&C->path] = CE->getCalleeContext(); 1731 1732 // Add the edge to the return site. 1733 addEdgeToPath(PD.getActivePath(), PrevLoc, C->callReturn, PDB.LC); 1734 PD.getActivePath().push_front(C); 1735 PrevLoc.invalidate(); 1736 1737 // Make the contents of the call the active path for now. 1738 PD.pushActivePath(&C->path); 1739 CallStack.push_back(StackDiagPair(C, N)); 1740 break; 1741 } 1742 1743 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1744 // For expressions, make sure we propagate the 1745 // interesting symbols correctly. 1746 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1747 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1748 N->getState().get(), Ex, 1749 N->getLocationContext()); 1750 1751 // Add an edge. If this is an ObjCForCollectionStmt do 1752 // not add an edge here as it appears in the CFG both 1753 // as a terminator and as a terminator condition. 1754 if (!isa<ObjCForCollectionStmt>(PS->getStmt())) { 1755 PathDiagnosticLocation L = 1756 PathDiagnosticLocation(PS->getStmt(), SM, PDB.LC); 1757 addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC); 1758 } 1759 break; 1760 } 1761 1762 // Block edges. 1763 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1764 // Does this represent entering a call? If so, look at propagating 1765 // interesting symbols across call boundaries. 1766 if (NextNode) { 1767 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1768 const LocationContext *CalleeCtx = PDB.LC; 1769 if (CallerCtx != CalleeCtx) { 1770 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1771 N->getState().get(), 1772 CalleeCtx, CallerCtx); 1773 } 1774 } 1775 1776 // Are we jumping to the head of a loop? Add a special diagnostic. 1777 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1778 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1779 const Stmt *Body = nullptr; 1780 1781 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1782 Body = FS->getBody(); 1783 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1784 Body = WS->getBody(); 1785 else if (const ObjCForCollectionStmt *OFS = 1786 dyn_cast<ObjCForCollectionStmt>(Loop)) { 1787 Body = OFS->getBody(); 1788 } else if (const CXXForRangeStmt *FRS = 1789 dyn_cast<CXXForRangeStmt>(Loop)) { 1790 Body = FRS->getBody(); 1791 } 1792 // do-while statements are explicitly excluded here 1793 1794 PathDiagnosticEventPiece *p = 1795 new PathDiagnosticEventPiece(L, "Looping back to the head " 1796 "of the loop"); 1797 p->setPrunable(true); 1798 1799 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC); 1800 PD.getActivePath().push_front(p); 1801 1802 if (const CompoundStmt *CS = dyn_cast_or_null<CompoundStmt>(Body)) { 1803 addEdgeToPath(PD.getActivePath(), PrevLoc, 1804 PathDiagnosticLocation::createEndBrace(CS, SM), 1805 PDB.LC); 1806 } 1807 } 1808 1809 const CFGBlock *BSrc = BE->getSrc(); 1810 ParentMap &PM = PDB.getParentMap(); 1811 1812 if (const Stmt *Term = BSrc->getTerminator()) { 1813 // Are we jumping past the loop body without ever executing the 1814 // loop (because the condition was false)? 1815 if (isLoop(Term)) { 1816 const Stmt *TermCond = getTerminatorCondition(BSrc); 1817 bool IsInLoopBody = 1818 isInLoopBody(PM, getStmtBeforeCond(PM, TermCond, N), Term); 1819 1820 const char *str = nullptr; 1821 1822 if (isJumpToFalseBranch(&*BE)) { 1823 if (!IsInLoopBody) { 1824 if (isa<ObjCForCollectionStmt>(Term)) { 1825 str = StrLoopCollectionEmpty; 1826 } else if (isa<CXXForRangeStmt>(Term)) { 1827 str = StrLoopRangeEmpty; 1828 } else { 1829 str = StrLoopBodyZero; 1830 } 1831 } 1832 } else { 1833 str = StrEnteringLoop; 1834 } 1835 1836 if (str) { 1837 PathDiagnosticLocation L(TermCond ? TermCond : Term, SM, PDB.LC); 1838 PathDiagnosticEventPiece *PE = 1839 new PathDiagnosticEventPiece(L, str); 1840 PE->setPrunable(true); 1841 addEdgeToPath(PD.getActivePath(), PrevLoc, 1842 PE->getLocation(), PDB.LC); 1843 PD.getActivePath().push_front(PE); 1844 } 1845 } else if (isa<BreakStmt>(Term) || isa<ContinueStmt>(Term) || 1846 isa<GotoStmt>(Term)) { 1847 PathDiagnosticLocation L(Term, SM, PDB.LC); 1848 addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC); 1849 } 1850 } 1851 break; 1852 } 1853 } while (0); 1854 1855 if (!NextNode) 1856 continue; 1857 1858 // Add pieces from custom visitors. 1859 for (auto &V : visitors) { 1860 if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *report)) { 1861 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC); 1862 PD.getActivePath().push_front(p); 1863 updateStackPiecesWithMessage(p, CallStack); 1864 } 1865 } 1866 } 1867 1868 // Add an edge to the start of the function. 1869 // We'll prune it out later, but it helps make diagnostics more uniform. 1870 const StackFrameContext *CalleeLC = PDB.LC->getCurrentStackFrame(); 1871 const Decl *D = CalleeLC->getDecl(); 1872 addEdgeToPath(PD.getActivePath(), PrevLoc, 1873 PathDiagnosticLocation::createBegin(D, SM), 1874 CalleeLC); 1875 1876 return report->isValid(); 1877 } 1878 1879 static const Stmt *getLocStmt(PathDiagnosticLocation L) { 1880 if (!L.isValid()) 1881 return nullptr; 1882 return L.asStmt(); 1883 } 1884 1885 static const Stmt *getStmtParent(const Stmt *S, const ParentMap &PM) { 1886 if (!S) 1887 return nullptr; 1888 1889 while (true) { 1890 S = PM.getParentIgnoreParens(S); 1891 1892 if (!S) 1893 break; 1894 1895 if (isa<ExprWithCleanups>(S) || 1896 isa<CXXBindTemporaryExpr>(S) || 1897 isa<SubstNonTypeTemplateParmExpr>(S)) 1898 continue; 1899 1900 break; 1901 } 1902 1903 return S; 1904 } 1905 1906 static bool isConditionForTerminator(const Stmt *S, const Stmt *Cond) { 1907 switch (S->getStmtClass()) { 1908 case Stmt::BinaryOperatorClass: { 1909 const BinaryOperator *BO = cast<BinaryOperator>(S); 1910 if (!BO->isLogicalOp()) 1911 return false; 1912 return BO->getLHS() == Cond || BO->getRHS() == Cond; 1913 } 1914 case Stmt::IfStmtClass: 1915 return cast<IfStmt>(S)->getCond() == Cond; 1916 case Stmt::ForStmtClass: 1917 return cast<ForStmt>(S)->getCond() == Cond; 1918 case Stmt::WhileStmtClass: 1919 return cast<WhileStmt>(S)->getCond() == Cond; 1920 case Stmt::DoStmtClass: 1921 return cast<DoStmt>(S)->getCond() == Cond; 1922 case Stmt::ChooseExprClass: 1923 return cast<ChooseExpr>(S)->getCond() == Cond; 1924 case Stmt::IndirectGotoStmtClass: 1925 return cast<IndirectGotoStmt>(S)->getTarget() == Cond; 1926 case Stmt::SwitchStmtClass: 1927 return cast<SwitchStmt>(S)->getCond() == Cond; 1928 case Stmt::BinaryConditionalOperatorClass: 1929 return cast<BinaryConditionalOperator>(S)->getCond() == Cond; 1930 case Stmt::ConditionalOperatorClass: { 1931 const ConditionalOperator *CO = cast<ConditionalOperator>(S); 1932 return CO->getCond() == Cond || 1933 CO->getLHS() == Cond || 1934 CO->getRHS() == Cond; 1935 } 1936 case Stmt::ObjCForCollectionStmtClass: 1937 return cast<ObjCForCollectionStmt>(S)->getElement() == Cond; 1938 case Stmt::CXXForRangeStmtClass: { 1939 const CXXForRangeStmt *FRS = cast<CXXForRangeStmt>(S); 1940 return FRS->getCond() == Cond || FRS->getRangeInit() == Cond; 1941 } 1942 default: 1943 return false; 1944 } 1945 } 1946 1947 static bool isIncrementOrInitInForLoop(const Stmt *S, const Stmt *FL) { 1948 if (const ForStmt *FS = dyn_cast<ForStmt>(FL)) 1949 return FS->getInc() == S || FS->getInit() == S; 1950 if (const CXXForRangeStmt *FRS = dyn_cast<CXXForRangeStmt>(FL)) 1951 return FRS->getInc() == S || FRS->getRangeStmt() == S || 1952 FRS->getLoopVarStmt() || FRS->getRangeInit() == S; 1953 return false; 1954 } 1955 1956 typedef llvm::DenseSet<const PathDiagnosticCallPiece *> 1957 OptimizedCallsSet; 1958 1959 /// Adds synthetic edges from top-level statements to their subexpressions. 1960 /// 1961 /// This avoids a "swoosh" effect, where an edge from a top-level statement A 1962 /// points to a sub-expression B.1 that's not at the start of B. In these cases, 1963 /// we'd like to see an edge from A to B, then another one from B to B.1. 1964 static void addContextEdges(PathPieces &pieces, SourceManager &SM, 1965 const ParentMap &PM, const LocationContext *LCtx) { 1966 PathPieces::iterator Prev = pieces.end(); 1967 for (PathPieces::iterator I = pieces.begin(), E = Prev; I != E; 1968 Prev = I, ++I) { 1969 PathDiagnosticControlFlowPiece *Piece = 1970 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 1971 1972 if (!Piece) 1973 continue; 1974 1975 PathDiagnosticLocation SrcLoc = Piece->getStartLocation(); 1976 SmallVector<PathDiagnosticLocation, 4> SrcContexts; 1977 1978 PathDiagnosticLocation NextSrcContext = SrcLoc; 1979 const Stmt *InnerStmt = nullptr; 1980 while (NextSrcContext.isValid() && NextSrcContext.asStmt() != InnerStmt) { 1981 SrcContexts.push_back(NextSrcContext); 1982 InnerStmt = NextSrcContext.asStmt(); 1983 NextSrcContext = getEnclosingStmtLocation(InnerStmt, SM, PM, LCtx, 1984 /*allowNested=*/true); 1985 } 1986 1987 // Repeatedly split the edge as necessary. 1988 // This is important for nested logical expressions (||, &&, ?:) where we 1989 // want to show all the levels of context. 1990 while (true) { 1991 const Stmt *Dst = getLocStmt(Piece->getEndLocation()); 1992 1993 // We are looking at an edge. Is the destination within a larger 1994 // expression? 1995 PathDiagnosticLocation DstContext = 1996 getEnclosingStmtLocation(Dst, SM, PM, LCtx, /*allowNested=*/true); 1997 if (!DstContext.isValid() || DstContext.asStmt() == Dst) 1998 break; 1999 2000 // If the source is in the same context, we're already good. 2001 if (std::find(SrcContexts.begin(), SrcContexts.end(), DstContext) != 2002 SrcContexts.end()) 2003 break; 2004 2005 // Update the subexpression node to point to the context edge. 2006 Piece->setStartLocation(DstContext); 2007 2008 // Try to extend the previous edge if it's at the same level as the source 2009 // context. 2010 if (Prev != E) { 2011 PathDiagnosticControlFlowPiece *PrevPiece = 2012 dyn_cast<PathDiagnosticControlFlowPiece>(*Prev); 2013 2014 if (PrevPiece) { 2015 if (const Stmt *PrevSrc = getLocStmt(PrevPiece->getStartLocation())) { 2016 const Stmt *PrevSrcParent = getStmtParent(PrevSrc, PM); 2017 if (PrevSrcParent == getStmtParent(getLocStmt(DstContext), PM)) { 2018 PrevPiece->setEndLocation(DstContext); 2019 break; 2020 } 2021 } 2022 } 2023 } 2024 2025 // Otherwise, split the current edge into a context edge and a 2026 // subexpression edge. Note that the context statement may itself have 2027 // context. 2028 Piece = new PathDiagnosticControlFlowPiece(SrcLoc, DstContext); 2029 I = pieces.insert(I, Piece); 2030 } 2031 } 2032 } 2033 2034 /// \brief Move edges from a branch condition to a branch target 2035 /// when the condition is simple. 2036 /// 2037 /// This restructures some of the work of addContextEdges. That function 2038 /// creates edges this may destroy, but they work together to create a more 2039 /// aesthetically set of edges around branches. After the call to 2040 /// addContextEdges, we may have (1) an edge to the branch, (2) an edge from 2041 /// the branch to the branch condition, and (3) an edge from the branch 2042 /// condition to the branch target. We keep (1), but may wish to remove (2) 2043 /// and move the source of (3) to the branch if the branch condition is simple. 2044 /// 2045 static void simplifySimpleBranches(PathPieces &pieces) { 2046 for (PathPieces::iterator I = pieces.begin(), E = pieces.end(); I != E; ++I) { 2047 2048 PathDiagnosticControlFlowPiece *PieceI = 2049 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2050 2051 if (!PieceI) 2052 continue; 2053 2054 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation()); 2055 const Stmt *s1End = getLocStmt(PieceI->getEndLocation()); 2056 2057 if (!s1Start || !s1End) 2058 continue; 2059 2060 PathPieces::iterator NextI = I; ++NextI; 2061 if (NextI == E) 2062 break; 2063 2064 PathDiagnosticControlFlowPiece *PieceNextI = nullptr; 2065 2066 while (true) { 2067 if (NextI == E) 2068 break; 2069 2070 PathDiagnosticEventPiece *EV = dyn_cast<PathDiagnosticEventPiece>(*NextI); 2071 if (EV) { 2072 StringRef S = EV->getString(); 2073 if (S == StrEnteringLoop || S == StrLoopBodyZero || 2074 S == StrLoopCollectionEmpty || S == StrLoopRangeEmpty) { 2075 ++NextI; 2076 continue; 2077 } 2078 break; 2079 } 2080 2081 PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 2082 break; 2083 } 2084 2085 if (!PieceNextI) 2086 continue; 2087 2088 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation()); 2089 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation()); 2090 2091 if (!s2Start || !s2End || s1End != s2Start) 2092 continue; 2093 2094 // We only perform this transformation for specific branch kinds. 2095 // We don't want to do this for do..while, for example. 2096 if (!(isa<ForStmt>(s1Start) || isa<WhileStmt>(s1Start) || 2097 isa<IfStmt>(s1Start) || isa<ObjCForCollectionStmt>(s1Start) || 2098 isa<CXXForRangeStmt>(s1Start))) 2099 continue; 2100 2101 // Is s1End the branch condition? 2102 if (!isConditionForTerminator(s1Start, s1End)) 2103 continue; 2104 2105 // Perform the hoisting by eliminating (2) and changing the start 2106 // location of (3). 2107 PieceNextI->setStartLocation(PieceI->getStartLocation()); 2108 I = pieces.erase(I); 2109 } 2110 } 2111 2112 /// Returns the number of bytes in the given (character-based) SourceRange. 2113 /// 2114 /// If the locations in the range are not on the same line, returns None. 2115 /// 2116 /// Note that this does not do a precise user-visible character or column count. 2117 static Optional<size_t> getLengthOnSingleLine(SourceManager &SM, 2118 SourceRange Range) { 2119 SourceRange ExpansionRange(SM.getExpansionLoc(Range.getBegin()), 2120 SM.getExpansionRange(Range.getEnd()).second); 2121 2122 FileID FID = SM.getFileID(ExpansionRange.getBegin()); 2123 if (FID != SM.getFileID(ExpansionRange.getEnd())) 2124 return None; 2125 2126 bool Invalid; 2127 const llvm::MemoryBuffer *Buffer = SM.getBuffer(FID, &Invalid); 2128 if (Invalid) 2129 return None; 2130 2131 unsigned BeginOffset = SM.getFileOffset(ExpansionRange.getBegin()); 2132 unsigned EndOffset = SM.getFileOffset(ExpansionRange.getEnd()); 2133 StringRef Snippet = Buffer->getBuffer().slice(BeginOffset, EndOffset); 2134 2135 // We're searching the raw bytes of the buffer here, which might include 2136 // escaped newlines and such. That's okay; we're trying to decide whether the 2137 // SourceRange is covering a large or small amount of space in the user's 2138 // editor. 2139 if (Snippet.find_first_of("\r\n") != StringRef::npos) 2140 return None; 2141 2142 // This isn't Unicode-aware, but it doesn't need to be. 2143 return Snippet.size(); 2144 } 2145 2146 /// \sa getLengthOnSingleLine(SourceManager, SourceRange) 2147 static Optional<size_t> getLengthOnSingleLine(SourceManager &SM, 2148 const Stmt *S) { 2149 return getLengthOnSingleLine(SM, S->getSourceRange()); 2150 } 2151 2152 /// Eliminate two-edge cycles created by addContextEdges(). 2153 /// 2154 /// Once all the context edges are in place, there are plenty of cases where 2155 /// there's a single edge from a top-level statement to a subexpression, 2156 /// followed by a single path note, and then a reverse edge to get back out to 2157 /// the top level. If the statement is simple enough, the subexpression edges 2158 /// just add noise and make it harder to understand what's going on. 2159 /// 2160 /// This function only removes edges in pairs, because removing only one edge 2161 /// might leave other edges dangling. 2162 /// 2163 /// This will not remove edges in more complicated situations: 2164 /// - if there is more than one "hop" leading to or from a subexpression. 2165 /// - if there is an inlined call between the edges instead of a single event. 2166 /// - if the whole statement is large enough that having subexpression arrows 2167 /// might be helpful. 2168 static void removeContextCycles(PathPieces &Path, SourceManager &SM, 2169 ParentMap &PM) { 2170 for (PathPieces::iterator I = Path.begin(), E = Path.end(); I != E; ) { 2171 // Pattern match the current piece and its successor. 2172 PathDiagnosticControlFlowPiece *PieceI = 2173 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2174 2175 if (!PieceI) { 2176 ++I; 2177 continue; 2178 } 2179 2180 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation()); 2181 const Stmt *s1End = getLocStmt(PieceI->getEndLocation()); 2182 2183 PathPieces::iterator NextI = I; ++NextI; 2184 if (NextI == E) 2185 break; 2186 2187 PathDiagnosticControlFlowPiece *PieceNextI = 2188 dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 2189 2190 if (!PieceNextI) { 2191 if (isa<PathDiagnosticEventPiece>(*NextI)) { 2192 ++NextI; 2193 if (NextI == E) 2194 break; 2195 PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 2196 } 2197 2198 if (!PieceNextI) { 2199 ++I; 2200 continue; 2201 } 2202 } 2203 2204 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation()); 2205 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation()); 2206 2207 if (s1Start && s2Start && s1Start == s2End && s2Start == s1End) { 2208 const size_t MAX_SHORT_LINE_LENGTH = 80; 2209 Optional<size_t> s1Length = getLengthOnSingleLine(SM, s1Start); 2210 if (s1Length && *s1Length <= MAX_SHORT_LINE_LENGTH) { 2211 Optional<size_t> s2Length = getLengthOnSingleLine(SM, s2Start); 2212 if (s2Length && *s2Length <= MAX_SHORT_LINE_LENGTH) { 2213 Path.erase(I); 2214 I = Path.erase(NextI); 2215 continue; 2216 } 2217 } 2218 } 2219 2220 ++I; 2221 } 2222 } 2223 2224 /// \brief Return true if X is contained by Y. 2225 static bool lexicalContains(ParentMap &PM, 2226 const Stmt *X, 2227 const Stmt *Y) { 2228 while (X) { 2229 if (X == Y) 2230 return true; 2231 X = PM.getParent(X); 2232 } 2233 return false; 2234 } 2235 2236 // Remove short edges on the same line less than 3 columns in difference. 2237 static void removePunyEdges(PathPieces &path, 2238 SourceManager &SM, 2239 ParentMap &PM) { 2240 2241 bool erased = false; 2242 2243 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; 2244 erased ? I : ++I) { 2245 2246 erased = false; 2247 2248 PathDiagnosticControlFlowPiece *PieceI = 2249 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2250 2251 if (!PieceI) 2252 continue; 2253 2254 const Stmt *start = getLocStmt(PieceI->getStartLocation()); 2255 const Stmt *end = getLocStmt(PieceI->getEndLocation()); 2256 2257 if (!start || !end) 2258 continue; 2259 2260 const Stmt *endParent = PM.getParent(end); 2261 if (!endParent) 2262 continue; 2263 2264 if (isConditionForTerminator(end, endParent)) 2265 continue; 2266 2267 SourceLocation FirstLoc = start->getLocStart(); 2268 SourceLocation SecondLoc = end->getLocStart(); 2269 2270 if (!SM.isWrittenInSameFile(FirstLoc, SecondLoc)) 2271 continue; 2272 if (SM.isBeforeInTranslationUnit(SecondLoc, FirstLoc)) 2273 std::swap(SecondLoc, FirstLoc); 2274 2275 SourceRange EdgeRange(FirstLoc, SecondLoc); 2276 Optional<size_t> ByteWidth = getLengthOnSingleLine(SM, EdgeRange); 2277 2278 // If the statements are on different lines, continue. 2279 if (!ByteWidth) 2280 continue; 2281 2282 const size_t MAX_PUNY_EDGE_LENGTH = 2; 2283 if (*ByteWidth <= MAX_PUNY_EDGE_LENGTH) { 2284 // FIXME: There are enough /bytes/ between the endpoints of the edge, but 2285 // there might not be enough /columns/. A proper user-visible column count 2286 // is probably too expensive, though. 2287 I = path.erase(I); 2288 erased = true; 2289 continue; 2290 } 2291 } 2292 } 2293 2294 static void removeIdenticalEvents(PathPieces &path) { 2295 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ++I) { 2296 PathDiagnosticEventPiece *PieceI = 2297 dyn_cast<PathDiagnosticEventPiece>(*I); 2298 2299 if (!PieceI) 2300 continue; 2301 2302 PathPieces::iterator NextI = I; ++NextI; 2303 if (NextI == E) 2304 return; 2305 2306 PathDiagnosticEventPiece *PieceNextI = 2307 dyn_cast<PathDiagnosticEventPiece>(*NextI); 2308 2309 if (!PieceNextI) 2310 continue; 2311 2312 // Erase the second piece if it has the same exact message text. 2313 if (PieceI->getString() == PieceNextI->getString()) { 2314 path.erase(NextI); 2315 } 2316 } 2317 } 2318 2319 static bool optimizeEdges(PathPieces &path, SourceManager &SM, 2320 OptimizedCallsSet &OCS, 2321 LocationContextMap &LCM) { 2322 bool hasChanges = false; 2323 const LocationContext *LC = LCM[&path]; 2324 assert(LC); 2325 ParentMap &PM = LC->getParentMap(); 2326 2327 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ) { 2328 // Optimize subpaths. 2329 if (PathDiagnosticCallPiece *CallI = dyn_cast<PathDiagnosticCallPiece>(*I)){ 2330 // Record the fact that a call has been optimized so we only do the 2331 // effort once. 2332 if (!OCS.count(CallI)) { 2333 while (optimizeEdges(CallI->path, SM, OCS, LCM)) {} 2334 OCS.insert(CallI); 2335 } 2336 ++I; 2337 continue; 2338 } 2339 2340 // Pattern match the current piece and its successor. 2341 PathDiagnosticControlFlowPiece *PieceI = 2342 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2343 2344 if (!PieceI) { 2345 ++I; 2346 continue; 2347 } 2348 2349 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation()); 2350 const Stmt *s1End = getLocStmt(PieceI->getEndLocation()); 2351 const Stmt *level1 = getStmtParent(s1Start, PM); 2352 const Stmt *level2 = getStmtParent(s1End, PM); 2353 2354 PathPieces::iterator NextI = I; ++NextI; 2355 if (NextI == E) 2356 break; 2357 2358 PathDiagnosticControlFlowPiece *PieceNextI = 2359 dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 2360 2361 if (!PieceNextI) { 2362 ++I; 2363 continue; 2364 } 2365 2366 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation()); 2367 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation()); 2368 const Stmt *level3 = getStmtParent(s2Start, PM); 2369 const Stmt *level4 = getStmtParent(s2End, PM); 2370 2371 // Rule I. 2372 // 2373 // If we have two consecutive control edges whose end/begin locations 2374 // are at the same level (e.g. statements or top-level expressions within 2375 // a compound statement, or siblings share a single ancestor expression), 2376 // then merge them if they have no interesting intermediate event. 2377 // 2378 // For example: 2379 // 2380 // (1.1 -> 1.2) -> (1.2 -> 1.3) becomes (1.1 -> 1.3) because the common 2381 // parent is '1'. Here 'x.y.z' represents the hierarchy of statements. 2382 // 2383 // NOTE: this will be limited later in cases where we add barriers 2384 // to prevent this optimization. 2385 // 2386 if (level1 && level1 == level2 && level1 == level3 && level1 == level4) { 2387 PieceI->setEndLocation(PieceNextI->getEndLocation()); 2388 path.erase(NextI); 2389 hasChanges = true; 2390 continue; 2391 } 2392 2393 // Rule II. 2394 // 2395 // Eliminate edges between subexpressions and parent expressions 2396 // when the subexpression is consumed. 2397 // 2398 // NOTE: this will be limited later in cases where we add barriers 2399 // to prevent this optimization. 2400 // 2401 if (s1End && s1End == s2Start && level2) { 2402 bool removeEdge = false; 2403 // Remove edges into the increment or initialization of a 2404 // loop that have no interleaving event. This means that 2405 // they aren't interesting. 2406 if (isIncrementOrInitInForLoop(s1End, level2)) 2407 removeEdge = true; 2408 // Next only consider edges that are not anchored on 2409 // the condition of a terminator. This are intermediate edges 2410 // that we might want to trim. 2411 else if (!isConditionForTerminator(level2, s1End)) { 2412 // Trim edges on expressions that are consumed by 2413 // the parent expression. 2414 if (isa<Expr>(s1End) && PM.isConsumedExpr(cast<Expr>(s1End))) { 2415 removeEdge = true; 2416 } 2417 // Trim edges where a lexical containment doesn't exist. 2418 // For example: 2419 // 2420 // X -> Y -> Z 2421 // 2422 // If 'Z' lexically contains Y (it is an ancestor) and 2423 // 'X' does not lexically contain Y (it is a descendant OR 2424 // it has no lexical relationship at all) then trim. 2425 // 2426 // This can eliminate edges where we dive into a subexpression 2427 // and then pop back out, etc. 2428 else if (s1Start && s2End && 2429 lexicalContains(PM, s2Start, s2End) && 2430 !lexicalContains(PM, s1End, s1Start)) { 2431 removeEdge = true; 2432 } 2433 // Trim edges from a subexpression back to the top level if the 2434 // subexpression is on a different line. 2435 // 2436 // A.1 -> A -> B 2437 // becomes 2438 // A.1 -> B 2439 // 2440 // These edges just look ugly and don't usually add anything. 2441 else if (s1Start && s2End && 2442 lexicalContains(PM, s1Start, s1End)) { 2443 SourceRange EdgeRange(PieceI->getEndLocation().asLocation(), 2444 PieceI->getStartLocation().asLocation()); 2445 if (!getLengthOnSingleLine(SM, EdgeRange).hasValue()) 2446 removeEdge = true; 2447 } 2448 } 2449 2450 if (removeEdge) { 2451 PieceI->setEndLocation(PieceNextI->getEndLocation()); 2452 path.erase(NextI); 2453 hasChanges = true; 2454 continue; 2455 } 2456 } 2457 2458 // Optimize edges for ObjC fast-enumeration loops. 2459 // 2460 // (X -> collection) -> (collection -> element) 2461 // 2462 // becomes: 2463 // 2464 // (X -> element) 2465 if (s1End == s2Start) { 2466 const ObjCForCollectionStmt *FS = 2467 dyn_cast_or_null<ObjCForCollectionStmt>(level3); 2468 if (FS && FS->getCollection()->IgnoreParens() == s2Start && 2469 s2End == FS->getElement()) { 2470 PieceI->setEndLocation(PieceNextI->getEndLocation()); 2471 path.erase(NextI); 2472 hasChanges = true; 2473 continue; 2474 } 2475 } 2476 2477 // No changes at this index? Move to the next one. 2478 ++I; 2479 } 2480 2481 if (!hasChanges) { 2482 // Adjust edges into subexpressions to make them more uniform 2483 // and aesthetically pleasing. 2484 addContextEdges(path, SM, PM, LC); 2485 // Remove "cyclical" edges that include one or more context edges. 2486 removeContextCycles(path, SM, PM); 2487 // Hoist edges originating from branch conditions to branches 2488 // for simple branches. 2489 simplifySimpleBranches(path); 2490 // Remove any puny edges left over after primary optimization pass. 2491 removePunyEdges(path, SM, PM); 2492 // Remove identical events. 2493 removeIdenticalEvents(path); 2494 } 2495 2496 return hasChanges; 2497 } 2498 2499 /// Drop the very first edge in a path, which should be a function entry edge. 2500 /// 2501 /// If the first edge is not a function entry edge (say, because the first 2502 /// statement had an invalid source location), this function does nothing. 2503 // FIXME: We should just generate invalid edges anyway and have the optimizer 2504 // deal with them. 2505 static void dropFunctionEntryEdge(PathPieces &Path, 2506 LocationContextMap &LCM, 2507 SourceManager &SM) { 2508 const PathDiagnosticControlFlowPiece *FirstEdge = 2509 dyn_cast<PathDiagnosticControlFlowPiece>(Path.front()); 2510 if (!FirstEdge) 2511 return; 2512 2513 const Decl *D = LCM[&Path]->getDecl(); 2514 PathDiagnosticLocation EntryLoc = PathDiagnosticLocation::createBegin(D, SM); 2515 if (FirstEdge->getStartLocation() != EntryLoc) 2516 return; 2517 2518 Path.pop_front(); 2519 } 2520 2521 2522 //===----------------------------------------------------------------------===// 2523 // Methods for BugType and subclasses. 2524 //===----------------------------------------------------------------------===// 2525 void BugType::anchor() { } 2526 2527 void BugType::FlushReports(BugReporter &BR) {} 2528 2529 void BuiltinBug::anchor() {} 2530 2531 //===----------------------------------------------------------------------===// 2532 // Methods for BugReport and subclasses. 2533 //===----------------------------------------------------------------------===// 2534 2535 void BugReport::NodeResolver::anchor() {} 2536 2537 void BugReport::addVisitor(std::unique_ptr<BugReporterVisitor> visitor) { 2538 if (!visitor) 2539 return; 2540 2541 llvm::FoldingSetNodeID ID; 2542 visitor->Profile(ID); 2543 void *InsertPos; 2544 2545 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) 2546 return; 2547 2548 CallbacksSet.InsertNode(visitor.get(), InsertPos); 2549 Callbacks.push_back(std::move(visitor)); 2550 ++ConfigurationChangeToken; 2551 } 2552 2553 BugReport::~BugReport() { 2554 while (!interestingSymbols.empty()) { 2555 popInterestingSymbolsAndRegions(); 2556 } 2557 } 2558 2559 const Decl *BugReport::getDeclWithIssue() const { 2560 if (DeclWithIssue) 2561 return DeclWithIssue; 2562 2563 const ExplodedNode *N = getErrorNode(); 2564 if (!N) 2565 return nullptr; 2566 2567 const LocationContext *LC = N->getLocationContext(); 2568 return LC->getCurrentStackFrame()->getDecl(); 2569 } 2570 2571 void BugReport::Profile(llvm::FoldingSetNodeID& hash) const { 2572 hash.AddPointer(&BT); 2573 hash.AddString(Description); 2574 PathDiagnosticLocation UL = getUniqueingLocation(); 2575 if (UL.isValid()) { 2576 UL.Profile(hash); 2577 } else if (Location.isValid()) { 2578 Location.Profile(hash); 2579 } else { 2580 assert(ErrorNode); 2581 hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode)); 2582 } 2583 2584 for (SmallVectorImpl<SourceRange>::const_iterator I = 2585 Ranges.begin(), E = Ranges.end(); I != E; ++I) { 2586 const SourceRange range = *I; 2587 if (!range.isValid()) 2588 continue; 2589 hash.AddInteger(range.getBegin().getRawEncoding()); 2590 hash.AddInteger(range.getEnd().getRawEncoding()); 2591 } 2592 } 2593 2594 void BugReport::markInteresting(SymbolRef sym) { 2595 if (!sym) 2596 return; 2597 2598 // If the symbol wasn't already in our set, note a configuration change. 2599 if (getInterestingSymbols().insert(sym).second) 2600 ++ConfigurationChangeToken; 2601 2602 if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym)) 2603 getInterestingRegions().insert(meta->getRegion()); 2604 } 2605 2606 void BugReport::markInteresting(const MemRegion *R) { 2607 if (!R) 2608 return; 2609 2610 // If the base region wasn't already in our set, note a configuration change. 2611 R = R->getBaseRegion(); 2612 if (getInterestingRegions().insert(R).second) 2613 ++ConfigurationChangeToken; 2614 2615 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2616 getInterestingSymbols().insert(SR->getSymbol()); 2617 } 2618 2619 void BugReport::markInteresting(SVal V) { 2620 markInteresting(V.getAsRegion()); 2621 markInteresting(V.getAsSymbol()); 2622 } 2623 2624 void BugReport::markInteresting(const LocationContext *LC) { 2625 if (!LC) 2626 return; 2627 InterestingLocationContexts.insert(LC); 2628 } 2629 2630 bool BugReport::isInteresting(SVal V) { 2631 return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol()); 2632 } 2633 2634 bool BugReport::isInteresting(SymbolRef sym) { 2635 if (!sym) 2636 return false; 2637 // We don't currently consider metadata symbols to be interesting 2638 // even if we know their region is interesting. Is that correct behavior? 2639 return getInterestingSymbols().count(sym); 2640 } 2641 2642 bool BugReport::isInteresting(const MemRegion *R) { 2643 if (!R) 2644 return false; 2645 R = R->getBaseRegion(); 2646 bool b = getInterestingRegions().count(R); 2647 if (b) 2648 return true; 2649 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2650 return getInterestingSymbols().count(SR->getSymbol()); 2651 return false; 2652 } 2653 2654 bool BugReport::isInteresting(const LocationContext *LC) { 2655 if (!LC) 2656 return false; 2657 return InterestingLocationContexts.count(LC); 2658 } 2659 2660 void BugReport::lazyInitializeInterestingSets() { 2661 if (interestingSymbols.empty()) { 2662 interestingSymbols.push_back(new Symbols()); 2663 interestingRegions.push_back(new Regions()); 2664 } 2665 } 2666 2667 BugReport::Symbols &BugReport::getInterestingSymbols() { 2668 lazyInitializeInterestingSets(); 2669 return *interestingSymbols.back(); 2670 } 2671 2672 BugReport::Regions &BugReport::getInterestingRegions() { 2673 lazyInitializeInterestingSets(); 2674 return *interestingRegions.back(); 2675 } 2676 2677 void BugReport::pushInterestingSymbolsAndRegions() { 2678 interestingSymbols.push_back(new Symbols(getInterestingSymbols())); 2679 interestingRegions.push_back(new Regions(getInterestingRegions())); 2680 } 2681 2682 void BugReport::popInterestingSymbolsAndRegions() { 2683 delete interestingSymbols.pop_back_val(); 2684 delete interestingRegions.pop_back_val(); 2685 } 2686 2687 const Stmt *BugReport::getStmt() const { 2688 if (!ErrorNode) 2689 return nullptr; 2690 2691 ProgramPoint ProgP = ErrorNode->getLocation(); 2692 const Stmt *S = nullptr; 2693 2694 if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) { 2695 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit(); 2696 if (BE->getBlock() == &Exit) 2697 S = GetPreviousStmt(ErrorNode); 2698 } 2699 if (!S) 2700 S = PathDiagnosticLocation::getStmt(ErrorNode); 2701 2702 return S; 2703 } 2704 2705 llvm::iterator_range<BugReport::ranges_iterator> BugReport::getRanges() { 2706 // If no custom ranges, add the range of the statement corresponding to 2707 // the error node. 2708 if (Ranges.empty()) { 2709 if (const Expr *E = dyn_cast_or_null<Expr>(getStmt())) 2710 addRange(E->getSourceRange()); 2711 else 2712 return llvm::make_range(ranges_iterator(), ranges_iterator()); 2713 } 2714 2715 // User-specified absence of range info. 2716 if (Ranges.size() == 1 && !Ranges.begin()->isValid()) 2717 return llvm::make_range(ranges_iterator(), ranges_iterator()); 2718 2719 return llvm::iterator_range<BugReport::ranges_iterator>(Ranges.begin(), 2720 Ranges.end()); 2721 } 2722 2723 PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const { 2724 if (ErrorNode) { 2725 assert(!Location.isValid() && 2726 "Either Location or ErrorNode should be specified but not both."); 2727 return PathDiagnosticLocation::createEndOfPath(ErrorNode, SM); 2728 } 2729 2730 assert(Location.isValid()); 2731 return Location; 2732 } 2733 2734 //===----------------------------------------------------------------------===// 2735 // Methods for BugReporter and subclasses. 2736 //===----------------------------------------------------------------------===// 2737 2738 BugReportEquivClass::~BugReportEquivClass() { } 2739 GRBugReporter::~GRBugReporter() { } 2740 BugReporterData::~BugReporterData() {} 2741 2742 ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); } 2743 2744 ProgramStateManager& 2745 GRBugReporter::getStateManager() { return Eng.getStateManager(); } 2746 2747 BugReporter::~BugReporter() { 2748 FlushReports(); 2749 2750 // Free the bug reports we are tracking. 2751 typedef std::vector<BugReportEquivClass *> ContTy; 2752 for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end(); 2753 I != E; ++I) { 2754 delete *I; 2755 } 2756 } 2757 2758 void BugReporter::FlushReports() { 2759 if (BugTypes.isEmpty()) 2760 return; 2761 2762 // First flush the warnings for each BugType. This may end up creating new 2763 // warnings and new BugTypes. 2764 // FIXME: Only NSErrorChecker needs BugType's FlushReports. 2765 // Turn NSErrorChecker into a proper checker and remove this. 2766 SmallVector<const BugType *, 16> bugTypes(BugTypes.begin(), BugTypes.end()); 2767 for (SmallVectorImpl<const BugType *>::iterator 2768 I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I) 2769 const_cast<BugType*>(*I)->FlushReports(*this); 2770 2771 // We need to flush reports in deterministic order to ensure the order 2772 // of the reports is consistent between runs. 2773 typedef std::vector<BugReportEquivClass *> ContVecTy; 2774 for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end(); 2775 EI != EE; ++EI){ 2776 BugReportEquivClass& EQ = **EI; 2777 FlushReport(EQ); 2778 } 2779 2780 // BugReporter owns and deletes only BugTypes created implicitly through 2781 // EmitBasicReport. 2782 // FIXME: There are leaks from checkers that assume that the BugTypes they 2783 // create will be destroyed by the BugReporter. 2784 llvm::DeleteContainerSeconds(StrBugTypes); 2785 2786 // Remove all references to the BugType objects. 2787 BugTypes = F.getEmptySet(); 2788 } 2789 2790 //===----------------------------------------------------------------------===// 2791 // PathDiagnostics generation. 2792 //===----------------------------------------------------------------------===// 2793 2794 namespace { 2795 /// A wrapper around a report graph, which contains only a single path, and its 2796 /// node maps. 2797 class ReportGraph { 2798 public: 2799 InterExplodedGraphMap BackMap; 2800 std::unique_ptr<ExplodedGraph> Graph; 2801 const ExplodedNode *ErrorNode; 2802 size_t Index; 2803 }; 2804 2805 /// A wrapper around a trimmed graph and its node maps. 2806 class TrimmedGraph { 2807 InterExplodedGraphMap InverseMap; 2808 2809 typedef llvm::DenseMap<const ExplodedNode *, unsigned> PriorityMapTy; 2810 PriorityMapTy PriorityMap; 2811 2812 typedef std::pair<const ExplodedNode *, size_t> NodeIndexPair; 2813 SmallVector<NodeIndexPair, 32> ReportNodes; 2814 2815 std::unique_ptr<ExplodedGraph> G; 2816 2817 /// A helper class for sorting ExplodedNodes by priority. 2818 template <bool Descending> 2819 class PriorityCompare { 2820 const PriorityMapTy &PriorityMap; 2821 2822 public: 2823 PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {} 2824 2825 bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const { 2826 PriorityMapTy::const_iterator LI = PriorityMap.find(LHS); 2827 PriorityMapTy::const_iterator RI = PriorityMap.find(RHS); 2828 PriorityMapTy::const_iterator E = PriorityMap.end(); 2829 2830 if (LI == E) 2831 return Descending; 2832 if (RI == E) 2833 return !Descending; 2834 2835 return Descending ? LI->second > RI->second 2836 : LI->second < RI->second; 2837 } 2838 2839 bool operator()(const NodeIndexPair &LHS, const NodeIndexPair &RHS) const { 2840 return (*this)(LHS.first, RHS.first); 2841 } 2842 }; 2843 2844 public: 2845 TrimmedGraph(const ExplodedGraph *OriginalGraph, 2846 ArrayRef<const ExplodedNode *> Nodes); 2847 2848 bool popNextReportGraph(ReportGraph &GraphWrapper); 2849 }; 2850 } 2851 2852 TrimmedGraph::TrimmedGraph(const ExplodedGraph *OriginalGraph, 2853 ArrayRef<const ExplodedNode *> Nodes) { 2854 // The trimmed graph is created in the body of the constructor to ensure 2855 // that the DenseMaps have been initialized already. 2856 InterExplodedGraphMap ForwardMap; 2857 G = OriginalGraph->trim(Nodes, &ForwardMap, &InverseMap); 2858 2859 // Find the (first) error node in the trimmed graph. We just need to consult 2860 // the node map which maps from nodes in the original graph to nodes 2861 // in the new graph. 2862 llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes; 2863 2864 for (unsigned i = 0, count = Nodes.size(); i < count; ++i) { 2865 if (const ExplodedNode *NewNode = ForwardMap.lookup(Nodes[i])) { 2866 ReportNodes.push_back(std::make_pair(NewNode, i)); 2867 RemainingNodes.insert(NewNode); 2868 } 2869 } 2870 2871 assert(!RemainingNodes.empty() && "No error node found in the trimmed graph"); 2872 2873 // Perform a forward BFS to find all the shortest paths. 2874 std::queue<const ExplodedNode *> WS; 2875 2876 assert(G->num_roots() == 1); 2877 WS.push(*G->roots_begin()); 2878 unsigned Priority = 0; 2879 2880 while (!WS.empty()) { 2881 const ExplodedNode *Node = WS.front(); 2882 WS.pop(); 2883 2884 PriorityMapTy::iterator PriorityEntry; 2885 bool IsNew; 2886 std::tie(PriorityEntry, IsNew) = 2887 PriorityMap.insert(std::make_pair(Node, Priority)); 2888 ++Priority; 2889 2890 if (!IsNew) { 2891 assert(PriorityEntry->second <= Priority); 2892 continue; 2893 } 2894 2895 if (RemainingNodes.erase(Node)) 2896 if (RemainingNodes.empty()) 2897 break; 2898 2899 for (ExplodedNode::const_pred_iterator I = Node->succ_begin(), 2900 E = Node->succ_end(); 2901 I != E; ++I) 2902 WS.push(*I); 2903 } 2904 2905 // Sort the error paths from longest to shortest. 2906 std::sort(ReportNodes.begin(), ReportNodes.end(), 2907 PriorityCompare<true>(PriorityMap)); 2908 } 2909 2910 bool TrimmedGraph::popNextReportGraph(ReportGraph &GraphWrapper) { 2911 if (ReportNodes.empty()) 2912 return false; 2913 2914 const ExplodedNode *OrigN; 2915 std::tie(OrigN, GraphWrapper.Index) = ReportNodes.pop_back_val(); 2916 assert(PriorityMap.find(OrigN) != PriorityMap.end() && 2917 "error node not accessible from root"); 2918 2919 // Create a new graph with a single path. This is the graph 2920 // that will be returned to the caller. 2921 auto GNew = llvm::make_unique<ExplodedGraph>(); 2922 GraphWrapper.BackMap.clear(); 2923 2924 // Now walk from the error node up the BFS path, always taking the 2925 // predeccessor with the lowest number. 2926 ExplodedNode *Succ = nullptr; 2927 while (true) { 2928 // Create the equivalent node in the new graph with the same state 2929 // and location. 2930 ExplodedNode *NewN = GNew->getNode(OrigN->getLocation(), OrigN->getState(), 2931 OrigN->isSink()); 2932 2933 // Store the mapping to the original node. 2934 InterExplodedGraphMap::const_iterator IMitr = InverseMap.find(OrigN); 2935 assert(IMitr != InverseMap.end() && "No mapping to original node."); 2936 GraphWrapper.BackMap[NewN] = IMitr->second; 2937 2938 // Link up the new node with the previous node. 2939 if (Succ) 2940 Succ->addPredecessor(NewN, *GNew); 2941 else 2942 GraphWrapper.ErrorNode = NewN; 2943 2944 Succ = NewN; 2945 2946 // Are we at the final node? 2947 if (OrigN->pred_empty()) { 2948 GNew->addRoot(NewN); 2949 break; 2950 } 2951 2952 // Find the next predeccessor node. We choose the node that is marked 2953 // with the lowest BFS number. 2954 OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(), 2955 PriorityCompare<false>(PriorityMap)); 2956 } 2957 2958 GraphWrapper.Graph = std::move(GNew); 2959 2960 return true; 2961 } 2962 2963 2964 /// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object 2965 /// and collapses PathDiagosticPieces that are expanded by macros. 2966 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) { 2967 typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>, 2968 SourceLocation> > MacroStackTy; 2969 2970 typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> > 2971 PiecesTy; 2972 2973 MacroStackTy MacroStack; 2974 PiecesTy Pieces; 2975 2976 for (PathPieces::const_iterator I = path.begin(), E = path.end(); 2977 I!=E; ++I) { 2978 2979 PathDiagnosticPiece *piece = I->get(); 2980 2981 // Recursively compact calls. 2982 if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){ 2983 CompactPathDiagnostic(call->path, SM); 2984 } 2985 2986 // Get the location of the PathDiagnosticPiece. 2987 const FullSourceLoc Loc = piece->getLocation().asLocation(); 2988 2989 // Determine the instantiation location, which is the location we group 2990 // related PathDiagnosticPieces. 2991 SourceLocation InstantiationLoc = Loc.isMacroID() ? 2992 SM.getExpansionLoc(Loc) : 2993 SourceLocation(); 2994 2995 if (Loc.isFileID()) { 2996 MacroStack.clear(); 2997 Pieces.push_back(piece); 2998 continue; 2999 } 3000 3001 assert(Loc.isMacroID()); 3002 3003 // Is the PathDiagnosticPiece within the same macro group? 3004 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) { 3005 MacroStack.back().first->subPieces.push_back(piece); 3006 continue; 3007 } 3008 3009 // We aren't in the same group. Are we descending into a new macro 3010 // or are part of an old one? 3011 IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup; 3012 3013 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ? 3014 SM.getExpansionLoc(Loc) : 3015 SourceLocation(); 3016 3017 // Walk the entire macro stack. 3018 while (!MacroStack.empty()) { 3019 if (InstantiationLoc == MacroStack.back().second) { 3020 MacroGroup = MacroStack.back().first; 3021 break; 3022 } 3023 3024 if (ParentInstantiationLoc == MacroStack.back().second) { 3025 MacroGroup = MacroStack.back().first; 3026 break; 3027 } 3028 3029 MacroStack.pop_back(); 3030 } 3031 3032 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) { 3033 // Create a new macro group and add it to the stack. 3034 PathDiagnosticMacroPiece *NewGroup = 3035 new PathDiagnosticMacroPiece( 3036 PathDiagnosticLocation::createSingleLocation(piece->getLocation())); 3037 3038 if (MacroGroup) 3039 MacroGroup->subPieces.push_back(NewGroup); 3040 else { 3041 assert(InstantiationLoc.isFileID()); 3042 Pieces.push_back(NewGroup); 3043 } 3044 3045 MacroGroup = NewGroup; 3046 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc)); 3047 } 3048 3049 // Finally, add the PathDiagnosticPiece to the group. 3050 MacroGroup->subPieces.push_back(piece); 3051 } 3052 3053 // Now take the pieces and construct a new PathDiagnostic. 3054 path.clear(); 3055 3056 path.insert(path.end(), Pieces.begin(), Pieces.end()); 3057 } 3058 3059 bool GRBugReporter::generatePathDiagnostic(PathDiagnostic& PD, 3060 PathDiagnosticConsumer &PC, 3061 ArrayRef<BugReport *> &bugReports) { 3062 assert(!bugReports.empty()); 3063 3064 bool HasValid = false; 3065 bool HasInvalid = false; 3066 SmallVector<const ExplodedNode *, 32> errorNodes; 3067 for (ArrayRef<BugReport*>::iterator I = bugReports.begin(), 3068 E = bugReports.end(); I != E; ++I) { 3069 if ((*I)->isValid()) { 3070 HasValid = true; 3071 errorNodes.push_back((*I)->getErrorNode()); 3072 } else { 3073 // Keep the errorNodes list in sync with the bugReports list. 3074 HasInvalid = true; 3075 errorNodes.push_back(nullptr); 3076 } 3077 } 3078 3079 // If all the reports have been marked invalid by a previous path generation, 3080 // we're done. 3081 if (!HasValid) 3082 return false; 3083 3084 typedef PathDiagnosticConsumer::PathGenerationScheme PathGenerationScheme; 3085 PathGenerationScheme ActiveScheme = PC.getGenerationScheme(); 3086 3087 if (ActiveScheme == PathDiagnosticConsumer::Extensive) { 3088 AnalyzerOptions &options = getAnalyzerOptions(); 3089 if (options.getBooleanOption("path-diagnostics-alternate", true)) { 3090 ActiveScheme = PathDiagnosticConsumer::AlternateExtensive; 3091 } 3092 } 3093 3094 TrimmedGraph TrimG(&getGraph(), errorNodes); 3095 ReportGraph ErrorGraph; 3096 3097 while (TrimG.popNextReportGraph(ErrorGraph)) { 3098 // Find the BugReport with the original location. 3099 assert(ErrorGraph.Index < bugReports.size()); 3100 BugReport *R = bugReports[ErrorGraph.Index]; 3101 assert(R && "No original report found for sliced graph."); 3102 assert(R->isValid() && "Report selected by trimmed graph marked invalid."); 3103 3104 // Start building the path diagnostic... 3105 PathDiagnosticBuilder PDB(*this, R, ErrorGraph.BackMap, &PC); 3106 const ExplodedNode *N = ErrorGraph.ErrorNode; 3107 3108 // Register additional node visitors. 3109 R->addVisitor(llvm::make_unique<NilReceiverBRVisitor>()); 3110 R->addVisitor(llvm::make_unique<ConditionBRVisitor>()); 3111 R->addVisitor(llvm::make_unique<LikelyFalsePositiveSuppressionBRVisitor>()); 3112 3113 BugReport::VisitorList visitors; 3114 unsigned origReportConfigToken, finalReportConfigToken; 3115 LocationContextMap LCM; 3116 3117 // While generating diagnostics, it's possible the visitors will decide 3118 // new symbols and regions are interesting, or add other visitors based on 3119 // the information they find. If they do, we need to regenerate the path 3120 // based on our new report configuration. 3121 do { 3122 // Get a clean copy of all the visitors. 3123 for (BugReport::visitor_iterator I = R->visitor_begin(), 3124 E = R->visitor_end(); I != E; ++I) 3125 visitors.push_back((*I)->clone()); 3126 3127 // Clear out the active path from any previous work. 3128 PD.resetPath(); 3129 origReportConfigToken = R->getConfigurationChangeToken(); 3130 3131 // Generate the very last diagnostic piece - the piece is visible before 3132 // the trace is expanded. 3133 std::unique_ptr<PathDiagnosticPiece> LastPiece; 3134 for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end(); 3135 I != E; ++I) { 3136 if (std::unique_ptr<PathDiagnosticPiece> Piece = 3137 (*I)->getEndPath(PDB, N, *R)) { 3138 assert (!LastPiece && 3139 "There can only be one final piece in a diagnostic."); 3140 LastPiece = std::move(Piece); 3141 } 3142 } 3143 3144 if (ActiveScheme != PathDiagnosticConsumer::None) { 3145 if (!LastPiece) 3146 LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R); 3147 assert(LastPiece); 3148 PD.setEndOfPath(std::move(LastPiece)); 3149 } 3150 3151 // Make sure we get a clean location context map so we don't 3152 // hold onto old mappings. 3153 LCM.clear(); 3154 3155 switch (ActiveScheme) { 3156 case PathDiagnosticConsumer::AlternateExtensive: 3157 GenerateAlternateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 3158 break; 3159 case PathDiagnosticConsumer::Extensive: 3160 GenerateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 3161 break; 3162 case PathDiagnosticConsumer::Minimal: 3163 GenerateMinimalPathDiagnostic(PD, PDB, N, LCM, visitors); 3164 break; 3165 case PathDiagnosticConsumer::None: 3166 GenerateVisitorsOnlyPathDiagnostic(PD, PDB, N, visitors); 3167 break; 3168 } 3169 3170 // Clean up the visitors we used. 3171 visitors.clear(); 3172 3173 // Did anything change while generating this path? 3174 finalReportConfigToken = R->getConfigurationChangeToken(); 3175 } while (finalReportConfigToken != origReportConfigToken); 3176 3177 if (!R->isValid()) 3178 continue; 3179 3180 // Finally, prune the diagnostic path of uninteresting stuff. 3181 if (!PD.path.empty()) { 3182 if (R->shouldPrunePath() && getAnalyzerOptions().shouldPrunePaths()) { 3183 bool stillHasNotes = removeUnneededCalls(PD.getMutablePieces(), R, LCM); 3184 assert(stillHasNotes); 3185 (void)stillHasNotes; 3186 } 3187 3188 // Redirect all call pieces to have valid locations. 3189 adjustCallLocations(PD.getMutablePieces()); 3190 removePiecesWithInvalidLocations(PD.getMutablePieces()); 3191 3192 if (ActiveScheme == PathDiagnosticConsumer::AlternateExtensive) { 3193 SourceManager &SM = getSourceManager(); 3194 3195 // Reduce the number of edges from a very conservative set 3196 // to an aesthetically pleasing subset that conveys the 3197 // necessary information. 3198 OptimizedCallsSet OCS; 3199 while (optimizeEdges(PD.getMutablePieces(), SM, OCS, LCM)) {} 3200 3201 // Drop the very first function-entry edge. It's not really necessary 3202 // for top-level functions. 3203 dropFunctionEntryEdge(PD.getMutablePieces(), LCM, SM); 3204 } 3205 3206 // Remove messages that are basically the same, and edges that may not 3207 // make sense. 3208 // We have to do this after edge optimization in the Extensive mode. 3209 removeRedundantMsgs(PD.getMutablePieces()); 3210 removeEdgesToDefaultInitializers(PD.getMutablePieces()); 3211 } 3212 3213 // We found a report and didn't suppress it. 3214 return true; 3215 } 3216 3217 // We suppressed all the reports in this equivalence class. 3218 assert(!HasInvalid && "Inconsistent suppression"); 3219 (void)HasInvalid; 3220 return false; 3221 } 3222 3223 void BugReporter::Register(BugType *BT) { 3224 BugTypes = F.add(BugTypes, BT); 3225 } 3226 3227 void BugReporter::emitReport(BugReport* R) { 3228 // To guarantee memory release. 3229 std::unique_ptr<BugReport> UniqueR(R); 3230 3231 if (const ExplodedNode *E = R->getErrorNode()) { 3232 const AnalysisDeclContext *DeclCtx = 3233 E->getLocationContext()->getAnalysisDeclContext(); 3234 // The source of autosynthesized body can be handcrafted AST or a model 3235 // file. The locations from handcrafted ASTs have no valid source locations 3236 // and have to be discarded. Locations from model files should be preserved 3237 // for processing and reporting. 3238 if (DeclCtx->isBodyAutosynthesized() && 3239 !DeclCtx->isBodyAutosynthesizedFromModelFile()) 3240 return; 3241 } 3242 3243 bool ValidSourceLoc = R->getLocation(getSourceManager()).isValid(); 3244 assert(ValidSourceLoc); 3245 // If we mess up in a release build, we'd still prefer to just drop the bug 3246 // instead of trying to go on. 3247 if (!ValidSourceLoc) 3248 return; 3249 3250 // Compute the bug report's hash to determine its equivalence class. 3251 llvm::FoldingSetNodeID ID; 3252 R->Profile(ID); 3253 3254 // Lookup the equivance class. If there isn't one, create it. 3255 BugType& BT = R->getBugType(); 3256 Register(&BT); 3257 void *InsertPos; 3258 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos); 3259 3260 if (!EQ) { 3261 EQ = new BugReportEquivClass(std::move(UniqueR)); 3262 EQClasses.InsertNode(EQ, InsertPos); 3263 EQClassesVector.push_back(EQ); 3264 } else 3265 EQ->AddReport(std::move(UniqueR)); 3266 } 3267 3268 3269 //===----------------------------------------------------------------------===// 3270 // Emitting reports in equivalence classes. 3271 //===----------------------------------------------------------------------===// 3272 3273 namespace { 3274 struct FRIEC_WLItem { 3275 const ExplodedNode *N; 3276 ExplodedNode::const_succ_iterator I, E; 3277 3278 FRIEC_WLItem(const ExplodedNode *n) 3279 : N(n), I(N->succ_begin()), E(N->succ_end()) {} 3280 }; 3281 } 3282 3283 static BugReport * 3284 FindReportInEquivalenceClass(BugReportEquivClass& EQ, 3285 SmallVectorImpl<BugReport*> &bugReports) { 3286 3287 BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end(); 3288 assert(I != E); 3289 BugType& BT = I->getBugType(); 3290 3291 // If we don't need to suppress any of the nodes because they are 3292 // post-dominated by a sink, simply add all the nodes in the equivalence class 3293 // to 'Nodes'. Any of the reports will serve as a "representative" report. 3294 if (!BT.isSuppressOnSink()) { 3295 BugReport *R = I; 3296 for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) { 3297 const ExplodedNode *N = I->getErrorNode(); 3298 if (N) { 3299 R = I; 3300 bugReports.push_back(R); 3301 } 3302 } 3303 return R; 3304 } 3305 3306 // For bug reports that should be suppressed when all paths are post-dominated 3307 // by a sink node, iterate through the reports in the equivalence class 3308 // until we find one that isn't post-dominated (if one exists). We use a 3309 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write 3310 // this as a recursive function, but we don't want to risk blowing out the 3311 // stack for very long paths. 3312 BugReport *exampleReport = nullptr; 3313 3314 for (; I != E; ++I) { 3315 const ExplodedNode *errorNode = I->getErrorNode(); 3316 3317 if (!errorNode) 3318 continue; 3319 if (errorNode->isSink()) { 3320 llvm_unreachable( 3321 "BugType::isSuppressSink() should not be 'true' for sink end nodes"); 3322 } 3323 // No successors? By definition this nodes isn't post-dominated by a sink. 3324 if (errorNode->succ_empty()) { 3325 bugReports.push_back(I); 3326 if (!exampleReport) 3327 exampleReport = I; 3328 continue; 3329 } 3330 3331 // At this point we know that 'N' is not a sink and it has at least one 3332 // successor. Use a DFS worklist to find a non-sink end-of-path node. 3333 typedef FRIEC_WLItem WLItem; 3334 typedef SmallVector<WLItem, 10> DFSWorkList; 3335 llvm::DenseMap<const ExplodedNode *, unsigned> Visited; 3336 3337 DFSWorkList WL; 3338 WL.push_back(errorNode); 3339 Visited[errorNode] = 1; 3340 3341 while (!WL.empty()) { 3342 WLItem &WI = WL.back(); 3343 assert(!WI.N->succ_empty()); 3344 3345 for (; WI.I != WI.E; ++WI.I) { 3346 const ExplodedNode *Succ = *WI.I; 3347 // End-of-path node? 3348 if (Succ->succ_empty()) { 3349 // If we found an end-of-path node that is not a sink. 3350 if (!Succ->isSink()) { 3351 bugReports.push_back(I); 3352 if (!exampleReport) 3353 exampleReport = I; 3354 WL.clear(); 3355 break; 3356 } 3357 // Found a sink? Continue on to the next successor. 3358 continue; 3359 } 3360 // Mark the successor as visited. If it hasn't been explored, 3361 // enqueue it to the DFS worklist. 3362 unsigned &mark = Visited[Succ]; 3363 if (!mark) { 3364 mark = 1; 3365 WL.push_back(Succ); 3366 break; 3367 } 3368 } 3369 3370 // The worklist may have been cleared at this point. First 3371 // check if it is empty before checking the last item. 3372 if (!WL.empty() && &WL.back() == &WI) 3373 WL.pop_back(); 3374 } 3375 } 3376 3377 // ExampleReport will be NULL if all the nodes in the equivalence class 3378 // were post-dominated by sinks. 3379 return exampleReport; 3380 } 3381 3382 void BugReporter::FlushReport(BugReportEquivClass& EQ) { 3383 SmallVector<BugReport*, 10> bugReports; 3384 BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports); 3385 if (exampleReport) { 3386 for (PathDiagnosticConsumer *PDC : getPathDiagnosticConsumers()) { 3387 FlushReport(exampleReport, *PDC, bugReports); 3388 } 3389 } 3390 } 3391 3392 void BugReporter::FlushReport(BugReport *exampleReport, 3393 PathDiagnosticConsumer &PD, 3394 ArrayRef<BugReport*> bugReports) { 3395 3396 // FIXME: Make sure we use the 'R' for the path that was actually used. 3397 // Probably doesn't make a difference in practice. 3398 BugType& BT = exampleReport->getBugType(); 3399 3400 std::unique_ptr<PathDiagnostic> D(new PathDiagnostic( 3401 exampleReport->getBugType().getCheckName(), 3402 exampleReport->getDeclWithIssue(), exampleReport->getBugType().getName(), 3403 exampleReport->getDescription(), 3404 exampleReport->getShortDescription(/*Fallback=*/false), BT.getCategory(), 3405 exampleReport->getUniqueingLocation(), 3406 exampleReport->getUniqueingDecl())); 3407 3408 MaxBugClassSize = std::max(bugReports.size(), 3409 static_cast<size_t>(MaxBugClassSize)); 3410 3411 // Generate the full path diagnostic, using the generation scheme 3412 // specified by the PathDiagnosticConsumer. Note that we have to generate 3413 // path diagnostics even for consumers which do not support paths, because 3414 // the BugReporterVisitors may mark this bug as a false positive. 3415 if (!bugReports.empty()) 3416 if (!generatePathDiagnostic(*D.get(), PD, bugReports)) 3417 return; 3418 3419 MaxValidBugClassSize = std::max(bugReports.size(), 3420 static_cast<size_t>(MaxValidBugClassSize)); 3421 3422 // Examine the report and see if the last piece is in a header. Reset the 3423 // report location to the last piece in the main source file. 3424 AnalyzerOptions& Opts = getAnalyzerOptions(); 3425 if (Opts.shouldReportIssuesInMainSourceFile() && !Opts.AnalyzeAll) 3426 D->resetDiagnosticLocationToMainFile(); 3427 3428 // If the path is empty, generate a single step path with the location 3429 // of the issue. 3430 if (D->path.empty()) { 3431 PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager()); 3432 auto piece = llvm::make_unique<PathDiagnosticEventPiece>( 3433 L, exampleReport->getDescription()); 3434 for (const SourceRange &Range : exampleReport->getRanges()) 3435 piece->addRange(Range); 3436 D->setEndOfPath(std::move(piece)); 3437 } 3438 3439 // Get the meta data. 3440 const BugReport::ExtraTextList &Meta = exampleReport->getExtraText(); 3441 for (BugReport::ExtraTextList::const_iterator i = Meta.begin(), 3442 e = Meta.end(); i != e; ++i) { 3443 D->addMeta(*i); 3444 } 3445 3446 PD.HandlePathDiagnostic(std::move(D)); 3447 } 3448 3449 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue, 3450 const CheckerBase *Checker, 3451 StringRef Name, StringRef Category, 3452 StringRef Str, PathDiagnosticLocation Loc, 3453 ArrayRef<SourceRange> Ranges) { 3454 EmitBasicReport(DeclWithIssue, Checker->getCheckName(), Name, Category, Str, 3455 Loc, Ranges); 3456 } 3457 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue, 3458 CheckName CheckName, 3459 StringRef name, StringRef category, 3460 StringRef str, PathDiagnosticLocation Loc, 3461 ArrayRef<SourceRange> Ranges) { 3462 3463 // 'BT' is owned by BugReporter. 3464 BugType *BT = getBugTypeForName(CheckName, name, category); 3465 BugReport *R = new BugReport(*BT, str, Loc); 3466 R->setDeclWithIssue(DeclWithIssue); 3467 for (ArrayRef<SourceRange>::iterator I = Ranges.begin(), E = Ranges.end(); 3468 I != E; ++I) 3469 R->addRange(*I); 3470 emitReport(R); 3471 } 3472 3473 BugType *BugReporter::getBugTypeForName(CheckName CheckName, StringRef name, 3474 StringRef category) { 3475 SmallString<136> fullDesc; 3476 llvm::raw_svector_ostream(fullDesc) << CheckName.getName() << ":" << name 3477 << ":" << category; 3478 BugType *&BT = StrBugTypes[fullDesc]; 3479 if (!BT) 3480 BT = new BugType(CheckName, name, category); 3481 return BT; 3482 } 3483 3484 LLVM_DUMP_METHOD void PathPieces::dump() const { 3485 unsigned index = 0; 3486 for (PathPieces::const_iterator I = begin(), E = end(); I != E; ++I) { 3487 llvm::errs() << "[" << index++ << "] "; 3488 (*I)->dump(); 3489 llvm::errs() << "\n"; 3490 } 3491 } 3492 3493 void PathDiagnosticCallPiece::dump() const { 3494 llvm::errs() << "CALL\n--------------\n"; 3495 3496 if (const Stmt *SLoc = getLocStmt(getLocation())) 3497 SLoc->dump(); 3498 else if (const NamedDecl *ND = dyn_cast<NamedDecl>(getCallee())) 3499 llvm::errs() << *ND << "\n"; 3500 else 3501 getLocation().dump(); 3502 } 3503 3504 void PathDiagnosticEventPiece::dump() const { 3505 llvm::errs() << "EVENT\n--------------\n"; 3506 llvm::errs() << getString() << "\n"; 3507 llvm::errs() << " ---- at ----\n"; 3508 getLocation().dump(); 3509 } 3510 3511 void PathDiagnosticControlFlowPiece::dump() const { 3512 llvm::errs() << "CONTROL\n--------------\n"; 3513 getStartLocation().dump(); 3514 llvm::errs() << " ---- to ----\n"; 3515 getEndLocation().dump(); 3516 } 3517 3518 void PathDiagnosticMacroPiece::dump() const { 3519 llvm::errs() << "MACRO\n--------------\n"; 3520 // FIXME: Print which macro is being invoked. 3521 } 3522 3523 void PathDiagnosticLocation::dump() const { 3524 if (!isValid()) { 3525 llvm::errs() << "<INVALID>\n"; 3526 return; 3527 } 3528 3529 switch (K) { 3530 case RangeK: 3531 // FIXME: actually print the range. 3532 llvm::errs() << "<range>\n"; 3533 break; 3534 case SingleLocK: 3535 asLocation().dump(); 3536 llvm::errs() << "\n"; 3537 break; 3538 case StmtK: 3539 if (S) 3540 S->dump(); 3541 else 3542 llvm::errs() << "<NULL STMT>\n"; 3543 break; 3544 case DeclK: 3545 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(D)) 3546 llvm::errs() << *ND << "\n"; 3547 else if (isa<BlockDecl>(D)) 3548 // FIXME: Make this nicer. 3549 llvm::errs() << "<block>\n"; 3550 else if (D) 3551 llvm::errs() << "<unknown decl>\n"; 3552 else 3553 llvm::errs() << "<NULL DECL>\n"; 3554 break; 3555 } 3556 } 3557