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 #define DEBUG_TYPE "BugReporter" 16 17 #include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h" 18 #include "clang/AST/ASTContext.h" 19 #include "clang/AST/DeclObjC.h" 20 #include "clang/AST/Expr.h" 21 #include "clang/AST/ParentMap.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/OwningPtr.h" 32 #include "llvm/ADT/STLExtras.h" 33 #include "llvm/ADT/SmallString.h" 34 #include "llvm/ADT/Statistic.h" 35 #include "llvm/Support/raw_ostream.h" 36 #include <queue> 37 38 using namespace clang; 39 using namespace ento; 40 41 STATISTIC(MaxBugClassSize, 42 "The maximum number of bug reports in the same equivalence class"); 43 STATISTIC(MaxValidBugClassSize, 44 "The maximum number of bug reports in the same equivalence class " 45 "where at least one report is valid (not suppressed)"); 46 47 BugReporterVisitor::~BugReporterVisitor() {} 48 49 void BugReporterContext::anchor() {} 50 51 //===----------------------------------------------------------------------===// 52 // Helper routines for walking the ExplodedGraph and fetching statements. 53 //===----------------------------------------------------------------------===// 54 55 static inline const Stmt *GetStmt(const ProgramPoint &P) { 56 if (Optional<StmtPoint> SP = P.getAs<StmtPoint>()) 57 return SP->getStmt(); 58 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) 59 return BE->getSrc()->getTerminator(); 60 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) 61 return CE->getCallExpr(); 62 if (Optional<CallExitEnd> CEE = P.getAs<CallExitEnd>()) 63 return CEE->getCalleeContext()->getCallSite(); 64 65 return 0; 66 } 67 68 static inline const ExplodedNode* 69 GetPredecessorNode(const ExplodedNode *N) { 70 return N->pred_empty() ? NULL : *(N->pred_begin()); 71 } 72 73 static inline const ExplodedNode* 74 GetSuccessorNode(const ExplodedNode *N) { 75 return N->succ_empty() ? NULL : *(N->succ_begin()); 76 } 77 78 static const Stmt *GetPreviousStmt(const ExplodedNode *N) { 79 for (N = GetPredecessorNode(N); N; N = GetPredecessorNode(N)) 80 if (const Stmt *S = GetStmt(N->getLocation())) 81 return S; 82 83 return 0; 84 } 85 86 static const Stmt *GetNextStmt(const ExplodedNode *N) { 87 for (N = GetSuccessorNode(N); N; N = GetSuccessorNode(N)) 88 if (const Stmt *S = GetStmt(N->getLocation())) { 89 // Check if the statement is '?' or '&&'/'||'. These are "merges", 90 // not actual statement points. 91 switch (S->getStmtClass()) { 92 case Stmt::ChooseExprClass: 93 case Stmt::BinaryConditionalOperatorClass: continue; 94 case Stmt::ConditionalOperatorClass: continue; 95 case Stmt::BinaryOperatorClass: { 96 BinaryOperatorKind Op = cast<BinaryOperator>(S)->getOpcode(); 97 if (Op == BO_LAnd || Op == BO_LOr) 98 continue; 99 break; 100 } 101 default: 102 break; 103 } 104 return S; 105 } 106 107 return 0; 108 } 109 110 static inline const Stmt* 111 GetCurrentOrPreviousStmt(const ExplodedNode *N) { 112 if (const Stmt *S = GetStmt(N->getLocation())) 113 return S; 114 115 return GetPreviousStmt(N); 116 } 117 118 static inline const Stmt* 119 GetCurrentOrNextStmt(const ExplodedNode *N) { 120 if (const Stmt *S = GetStmt(N->getLocation())) 121 return S; 122 123 return GetNextStmt(N); 124 } 125 126 //===----------------------------------------------------------------------===// 127 // Diagnostic cleanup. 128 //===----------------------------------------------------------------------===// 129 130 static PathDiagnosticEventPiece * 131 eventsDescribeSameCondition(PathDiagnosticEventPiece *X, 132 PathDiagnosticEventPiece *Y) { 133 // Prefer diagnostics that come from ConditionBRVisitor over 134 // those that came from TrackConstraintBRVisitor. 135 const void *tagPreferred = ConditionBRVisitor::getTag(); 136 const void *tagLesser = TrackConstraintBRVisitor::getTag(); 137 138 if (X->getLocation() != Y->getLocation()) 139 return 0; 140 141 if (X->getTag() == tagPreferred && Y->getTag() == tagLesser) 142 return X; 143 144 if (Y->getTag() == tagPreferred && X->getTag() == tagLesser) 145 return Y; 146 147 return 0; 148 } 149 150 /// An optimization pass over PathPieces that removes redundant diagnostics 151 /// generated by both ConditionBRVisitor and TrackConstraintBRVisitor. Both 152 /// BugReporterVisitors use different methods to generate diagnostics, with 153 /// one capable of emitting diagnostics in some cases but not in others. This 154 /// can lead to redundant diagnostic pieces at the same point in a path. 155 static void removeRedundantMsgs(PathPieces &path) { 156 unsigned N = path.size(); 157 if (N < 2) 158 return; 159 // NOTE: this loop intentionally is not using an iterator. Instead, we 160 // are streaming the path and modifying it in place. This is done by 161 // grabbing the front, processing it, and if we decide to keep it append 162 // it to the end of the path. The entire path is processed in this way. 163 for (unsigned i = 0; i < N; ++i) { 164 IntrusiveRefCntPtr<PathDiagnosticPiece> piece(path.front()); 165 path.pop_front(); 166 167 switch (piece->getKind()) { 168 case clang::ento::PathDiagnosticPiece::Call: 169 removeRedundantMsgs(cast<PathDiagnosticCallPiece>(piece)->path); 170 break; 171 case clang::ento::PathDiagnosticPiece::Macro: 172 removeRedundantMsgs(cast<PathDiagnosticMacroPiece>(piece)->subPieces); 173 break; 174 case clang::ento::PathDiagnosticPiece::ControlFlow: 175 break; 176 case clang::ento::PathDiagnosticPiece::Event: { 177 if (i == N-1) 178 break; 179 180 if (PathDiagnosticEventPiece *nextEvent = 181 dyn_cast<PathDiagnosticEventPiece>(path.front().getPtr())) { 182 PathDiagnosticEventPiece *event = 183 cast<PathDiagnosticEventPiece>(piece); 184 // Check to see if we should keep one of the two pieces. If we 185 // come up with a preference, record which piece to keep, and consume 186 // another piece from the path. 187 if (PathDiagnosticEventPiece *pieceToKeep = 188 eventsDescribeSameCondition(event, nextEvent)) { 189 piece = pieceToKeep; 190 path.pop_front(); 191 ++i; 192 } 193 } 194 break; 195 } 196 } 197 path.push_back(piece); 198 } 199 } 200 201 /// Recursively scan through a path and prune out calls and macros pieces 202 /// that aren't needed. Return true if afterwards the path contains 203 /// "interesting stuff" which means it shouldn't be pruned from the parent path. 204 bool BugReporter::RemoveUnneededCalls(PathPieces &pieces, BugReport *R) { 205 bool containsSomethingInteresting = false; 206 const unsigned N = pieces.size(); 207 208 for (unsigned i = 0 ; i < N ; ++i) { 209 // Remove the front piece from the path. If it is still something we 210 // want to keep once we are done, we will push it back on the end. 211 IntrusiveRefCntPtr<PathDiagnosticPiece> piece(pieces.front()); 212 pieces.pop_front(); 213 214 // Throw away pieces with invalid locations. Note that we can't throw away 215 // calls just yet because they might have something interesting inside them. 216 // If so, their locations will be adjusted as necessary later. 217 if (piece->getKind() != PathDiagnosticPiece::Call && 218 piece->getLocation().asLocation().isInvalid()) 219 continue; 220 221 switch (piece->getKind()) { 222 case PathDiagnosticPiece::Call: { 223 PathDiagnosticCallPiece *call = cast<PathDiagnosticCallPiece>(piece); 224 // Check if the location context is interesting. 225 assert(LocationContextMap.count(call)); 226 if (R->isInteresting(LocationContextMap[call])) { 227 containsSomethingInteresting = true; 228 break; 229 } 230 231 if (!RemoveUnneededCalls(call->path, R)) 232 continue; 233 234 containsSomethingInteresting = true; 235 break; 236 } 237 case PathDiagnosticPiece::Macro: { 238 PathDiagnosticMacroPiece *macro = cast<PathDiagnosticMacroPiece>(piece); 239 if (!RemoveUnneededCalls(macro->subPieces, R)) 240 continue; 241 containsSomethingInteresting = true; 242 break; 243 } 244 case PathDiagnosticPiece::Event: { 245 PathDiagnosticEventPiece *event = cast<PathDiagnosticEventPiece>(piece); 246 247 // We never throw away an event, but we do throw it away wholesale 248 // as part of a path if we throw the entire path away. 249 containsSomethingInteresting |= !event->isPrunable(); 250 break; 251 } 252 case PathDiagnosticPiece::ControlFlow: 253 break; 254 } 255 256 pieces.push_back(piece); 257 } 258 259 return containsSomethingInteresting; 260 } 261 262 /// Recursively scan through a path and make sure that all call pieces have 263 /// valid locations. Note that all other pieces with invalid locations should 264 /// have already been pruned out. 265 static void adjustCallLocations(PathPieces &Pieces, 266 PathDiagnosticLocation *LastCallLocation = 0) { 267 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E; ++I) { 268 PathDiagnosticCallPiece *Call = dyn_cast<PathDiagnosticCallPiece>(*I); 269 270 if (!Call) { 271 assert((*I)->getLocation().asLocation().isValid()); 272 continue; 273 } 274 275 if (LastCallLocation) { 276 if (!Call->callEnter.asLocation().isValid() || 277 Call->getCaller()->isImplicit()) 278 Call->callEnter = *LastCallLocation; 279 if (!Call->callReturn.asLocation().isValid() || 280 Call->getCaller()->isImplicit()) 281 Call->callReturn = *LastCallLocation; 282 } 283 284 // Recursively clean out the subclass. Keep this call around if 285 // it contains any informative diagnostics. 286 PathDiagnosticLocation *ThisCallLocation; 287 if (Call->callEnterWithin.asLocation().isValid() && 288 !Call->getCallee()->isImplicit()) 289 ThisCallLocation = &Call->callEnterWithin; 290 else 291 ThisCallLocation = &Call->callEnter; 292 293 assert(ThisCallLocation && "Outermost call has an invalid location"); 294 adjustCallLocations(Call->path, ThisCallLocation); 295 } 296 } 297 298 //===----------------------------------------------------------------------===// 299 // PathDiagnosticBuilder and its associated routines and helper objects. 300 //===----------------------------------------------------------------------===// 301 302 namespace { 303 class NodeMapClosure : public BugReport::NodeResolver { 304 InterExplodedGraphMap &M; 305 public: 306 NodeMapClosure(InterExplodedGraphMap &m) : M(m) {} 307 308 const ExplodedNode *getOriginalNode(const ExplodedNode *N) { 309 return M.lookup(N); 310 } 311 }; 312 313 class PathDiagnosticBuilder : public BugReporterContext { 314 BugReport *R; 315 PathDiagnosticConsumer *PDC; 316 NodeMapClosure NMC; 317 public: 318 const LocationContext *LC; 319 320 PathDiagnosticBuilder(GRBugReporter &br, 321 BugReport *r, InterExplodedGraphMap &Backmap, 322 PathDiagnosticConsumer *pdc) 323 : BugReporterContext(br), 324 R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext()) 325 {} 326 327 PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N); 328 329 PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os, 330 const ExplodedNode *N); 331 332 BugReport *getBugReport() { return R; } 333 334 Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); } 335 336 ParentMap& getParentMap() { return LC->getParentMap(); } 337 338 const Stmt *getParent(const Stmt *S) { 339 return getParentMap().getParent(S); 340 } 341 342 virtual NodeMapClosure& getNodeResolver() { return NMC; } 343 344 PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S); 345 346 PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const { 347 return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive; 348 } 349 350 bool supportsLogicalOpControlFlow() const { 351 return PDC ? PDC->supportsLogicalOpControlFlow() : true; 352 } 353 }; 354 } // end anonymous namespace 355 356 PathDiagnosticLocation 357 PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) { 358 if (const Stmt *S = GetNextStmt(N)) 359 return PathDiagnosticLocation(S, getSourceManager(), LC); 360 361 return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(), 362 getSourceManager()); 363 } 364 365 PathDiagnosticLocation 366 PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os, 367 const ExplodedNode *N) { 368 369 // Slow, but probably doesn't matter. 370 if (os.str().empty()) 371 os << ' '; 372 373 const PathDiagnosticLocation &Loc = ExecutionContinues(N); 374 375 if (Loc.asStmt()) 376 os << "Execution continues on line " 377 << getSourceManager().getExpansionLineNumber(Loc.asLocation()) 378 << '.'; 379 else { 380 os << "Execution jumps to the end of the "; 381 const Decl *D = N->getLocationContext()->getDecl(); 382 if (isa<ObjCMethodDecl>(D)) 383 os << "method"; 384 else if (isa<FunctionDecl>(D)) 385 os << "function"; 386 else { 387 assert(isa<BlockDecl>(D)); 388 os << "anonymous block"; 389 } 390 os << '.'; 391 } 392 393 return Loc; 394 } 395 396 static bool IsNested(const Stmt *S, ParentMap &PM) { 397 if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S))) 398 return true; 399 400 const Stmt *Parent = PM.getParentIgnoreParens(S); 401 402 if (Parent) 403 switch (Parent->getStmtClass()) { 404 case Stmt::ForStmtClass: 405 case Stmt::DoStmtClass: 406 case Stmt::WhileStmtClass: 407 return true; 408 default: 409 break; 410 } 411 412 return false; 413 } 414 415 PathDiagnosticLocation 416 PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) { 417 assert(S && "Null Stmt *passed to getEnclosingStmtLocation"); 418 ParentMap &P = getParentMap(); 419 SourceManager &SMgr = getSourceManager(); 420 421 while (IsNested(S, P)) { 422 const Stmt *Parent = P.getParentIgnoreParens(S); 423 424 if (!Parent) 425 break; 426 427 switch (Parent->getStmtClass()) { 428 case Stmt::BinaryOperatorClass: { 429 const BinaryOperator *B = cast<BinaryOperator>(Parent); 430 if (B->isLogicalOp()) 431 return PathDiagnosticLocation(S, SMgr, LC); 432 break; 433 } 434 case Stmt::CompoundStmtClass: 435 case Stmt::StmtExprClass: 436 return PathDiagnosticLocation(S, SMgr, LC); 437 case Stmt::ChooseExprClass: 438 // Similar to '?' if we are referring to condition, just have the edge 439 // point to the entire choose expression. 440 if (cast<ChooseExpr>(Parent)->getCond() == S) 441 return PathDiagnosticLocation(Parent, SMgr, LC); 442 else 443 return PathDiagnosticLocation(S, SMgr, LC); 444 case Stmt::BinaryConditionalOperatorClass: 445 case Stmt::ConditionalOperatorClass: 446 // For '?', if we are referring to condition, just have the edge point 447 // to the entire '?' expression. 448 if (cast<AbstractConditionalOperator>(Parent)->getCond() == S) 449 return PathDiagnosticLocation(Parent, SMgr, LC); 450 else 451 return PathDiagnosticLocation(S, SMgr, LC); 452 case Stmt::DoStmtClass: 453 return PathDiagnosticLocation(S, SMgr, LC); 454 case Stmt::ForStmtClass: 455 if (cast<ForStmt>(Parent)->getBody() == S) 456 return PathDiagnosticLocation(S, SMgr, LC); 457 break; 458 case Stmt::IfStmtClass: 459 if (cast<IfStmt>(Parent)->getCond() != S) 460 return PathDiagnosticLocation(S, SMgr, LC); 461 break; 462 case Stmt::ObjCForCollectionStmtClass: 463 if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S) 464 return PathDiagnosticLocation(S, SMgr, LC); 465 break; 466 case Stmt::WhileStmtClass: 467 if (cast<WhileStmt>(Parent)->getCond() != S) 468 return PathDiagnosticLocation(S, SMgr, LC); 469 break; 470 default: 471 break; 472 } 473 474 S = Parent; 475 } 476 477 assert(S && "Cannot have null Stmt for PathDiagnosticLocation"); 478 479 // Special case: DeclStmts can appear in for statement declarations, in which 480 // case the ForStmt is the context. 481 if (isa<DeclStmt>(S)) { 482 if (const Stmt *Parent = P.getParent(S)) { 483 switch (Parent->getStmtClass()) { 484 case Stmt::ForStmtClass: 485 case Stmt::ObjCForCollectionStmtClass: 486 return PathDiagnosticLocation(Parent, SMgr, LC); 487 default: 488 break; 489 } 490 } 491 } 492 else if (isa<BinaryOperator>(S)) { 493 // Special case: the binary operator represents the initialization 494 // code in a for statement (this can happen when the variable being 495 // initialized is an old variable. 496 if (const ForStmt *FS = 497 dyn_cast_or_null<ForStmt>(P.getParentIgnoreParens(S))) { 498 if (FS->getInit() == S) 499 return PathDiagnosticLocation(FS, SMgr, LC); 500 } 501 } 502 503 return PathDiagnosticLocation(S, SMgr, LC); 504 } 505 506 //===----------------------------------------------------------------------===// 507 // "Visitors only" path diagnostic generation algorithm. 508 //===----------------------------------------------------------------------===// 509 static bool GenerateVisitorsOnlyPathDiagnostic(PathDiagnostic &PD, 510 PathDiagnosticBuilder &PDB, 511 const ExplodedNode *N, 512 ArrayRef<BugReporterVisitor *> visitors) { 513 // All path generation skips the very first node (the error node). 514 // This is because there is special handling for the end-of-path note. 515 N = N->getFirstPred(); 516 if (!N) 517 return true; 518 519 BugReport *R = PDB.getBugReport(); 520 while (const ExplodedNode *Pred = N->getFirstPred()) { 521 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 522 E = visitors.end(); 523 I != E; ++I) { 524 // Visit all the node pairs, but throw the path pieces away. 525 PathDiagnosticPiece *Piece = (*I)->VisitNode(N, Pred, PDB, *R); 526 delete Piece; 527 } 528 529 N = Pred; 530 } 531 532 return R->isValid(); 533 } 534 535 //===----------------------------------------------------------------------===// 536 // "Minimal" path diagnostic generation algorithm. 537 //===----------------------------------------------------------------------===// 538 typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair; 539 typedef SmallVector<StackDiagPair, 6> StackDiagVector; 540 541 static void updateStackPiecesWithMessage(PathDiagnosticPiece *P, 542 StackDiagVector &CallStack) { 543 // If the piece contains a special message, add it to all the call 544 // pieces on the active stack. 545 if (PathDiagnosticEventPiece *ep = 546 dyn_cast<PathDiagnosticEventPiece>(P)) { 547 548 if (ep->hasCallStackHint()) 549 for (StackDiagVector::iterator I = CallStack.begin(), 550 E = CallStack.end(); I != E; ++I) { 551 PathDiagnosticCallPiece *CP = I->first; 552 const ExplodedNode *N = I->second; 553 std::string stackMsg = ep->getCallStackMessage(N); 554 555 // The last message on the path to final bug is the most important 556 // one. Since we traverse the path backwards, do not add the message 557 // if one has been previously added. 558 if (!CP->hasCallStackMessage()) 559 CP->setCallStackMessage(stackMsg); 560 } 561 } 562 } 563 564 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM); 565 566 static bool GenerateMinimalPathDiagnostic(PathDiagnostic& PD, 567 PathDiagnosticBuilder &PDB, 568 const ExplodedNode *N, 569 ArrayRef<BugReporterVisitor *> visitors) { 570 571 SourceManager& SMgr = PDB.getSourceManager(); 572 const LocationContext *LC = PDB.LC; 573 const ExplodedNode *NextNode = N->pred_empty() 574 ? NULL : *(N->pred_begin()); 575 576 StackDiagVector CallStack; 577 578 while (NextNode) { 579 N = NextNode; 580 PDB.LC = N->getLocationContext(); 581 NextNode = GetPredecessorNode(N); 582 583 ProgramPoint P = N->getLocation(); 584 585 do { 586 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 587 PathDiagnosticCallPiece *C = 588 PathDiagnosticCallPiece::construct(N, *CE, SMgr); 589 GRBugReporter& BR = PDB.getBugReporter(); 590 BR.addCallPieceLocationContextPair(C, CE->getCalleeContext()); 591 PD.getActivePath().push_front(C); 592 PD.pushActivePath(&C->path); 593 CallStack.push_back(StackDiagPair(C, N)); 594 break; 595 } 596 597 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 598 // Flush all locations, and pop the active path. 599 bool VisitedEntireCall = PD.isWithinCall(); 600 PD.popActivePath(); 601 602 // Either we just added a bunch of stuff to the top-level path, or 603 // we have a previous CallExitEnd. If the former, it means that the 604 // path terminated within a function call. We must then take the 605 // current contents of the active path and place it within 606 // a new PathDiagnosticCallPiece. 607 PathDiagnosticCallPiece *C; 608 if (VisitedEntireCall) { 609 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 610 } else { 611 const Decl *Caller = CE->getLocationContext()->getDecl(); 612 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 613 GRBugReporter& BR = PDB.getBugReporter(); 614 BR.addCallPieceLocationContextPair(C, CE->getCalleeContext()); 615 } 616 617 C->setCallee(*CE, SMgr); 618 if (!CallStack.empty()) { 619 assert(CallStack.back().first == C); 620 CallStack.pop_back(); 621 } 622 break; 623 } 624 625 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 626 const CFGBlock *Src = BE->getSrc(); 627 const CFGBlock *Dst = BE->getDst(); 628 const Stmt *T = Src->getTerminator(); 629 630 if (!T) 631 break; 632 633 PathDiagnosticLocation Start = 634 PathDiagnosticLocation::createBegin(T, SMgr, 635 N->getLocationContext()); 636 637 switch (T->getStmtClass()) { 638 default: 639 break; 640 641 case Stmt::GotoStmtClass: 642 case Stmt::IndirectGotoStmtClass: { 643 const Stmt *S = GetNextStmt(N); 644 645 if (!S) 646 break; 647 648 std::string sbuf; 649 llvm::raw_string_ostream os(sbuf); 650 const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S); 651 652 os << "Control jumps to line " 653 << End.asLocation().getExpansionLineNumber(); 654 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 655 Start, End, os.str())); 656 break; 657 } 658 659 case Stmt::SwitchStmtClass: { 660 // Figure out what case arm we took. 661 std::string sbuf; 662 llvm::raw_string_ostream os(sbuf); 663 664 if (const Stmt *S = Dst->getLabel()) { 665 PathDiagnosticLocation End(S, SMgr, LC); 666 667 switch (S->getStmtClass()) { 668 default: 669 os << "No cases match in the switch statement. " 670 "Control jumps to line " 671 << End.asLocation().getExpansionLineNumber(); 672 break; 673 case Stmt::DefaultStmtClass: 674 os << "Control jumps to the 'default' case at line " 675 << End.asLocation().getExpansionLineNumber(); 676 break; 677 678 case Stmt::CaseStmtClass: { 679 os << "Control jumps to 'case "; 680 const CaseStmt *Case = cast<CaseStmt>(S); 681 const Expr *LHS = Case->getLHS()->IgnoreParenCasts(); 682 683 // Determine if it is an enum. 684 bool GetRawInt = true; 685 686 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) { 687 // FIXME: Maybe this should be an assertion. Are there cases 688 // were it is not an EnumConstantDecl? 689 const EnumConstantDecl *D = 690 dyn_cast<EnumConstantDecl>(DR->getDecl()); 691 692 if (D) { 693 GetRawInt = false; 694 os << *D; 695 } 696 } 697 698 if (GetRawInt) 699 os << LHS->EvaluateKnownConstInt(PDB.getASTContext()); 700 701 os << ":' at line " 702 << End.asLocation().getExpansionLineNumber(); 703 break; 704 } 705 } 706 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 707 Start, End, os.str())); 708 } 709 else { 710 os << "'Default' branch taken. "; 711 const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N); 712 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 713 Start, End, os.str())); 714 } 715 716 break; 717 } 718 719 case Stmt::BreakStmtClass: 720 case Stmt::ContinueStmtClass: { 721 std::string sbuf; 722 llvm::raw_string_ostream os(sbuf); 723 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 724 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 725 Start, End, os.str())); 726 break; 727 } 728 729 // Determine control-flow for ternary '?'. 730 case Stmt::BinaryConditionalOperatorClass: 731 case Stmt::ConditionalOperatorClass: { 732 std::string sbuf; 733 llvm::raw_string_ostream os(sbuf); 734 os << "'?' condition is "; 735 736 if (*(Src->succ_begin()+1) == Dst) 737 os << "false"; 738 else 739 os << "true"; 740 741 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 742 743 if (const Stmt *S = End.asStmt()) 744 End = PDB.getEnclosingStmtLocation(S); 745 746 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 747 Start, End, os.str())); 748 break; 749 } 750 751 // Determine control-flow for short-circuited '&&' and '||'. 752 case Stmt::BinaryOperatorClass: { 753 if (!PDB.supportsLogicalOpControlFlow()) 754 break; 755 756 const BinaryOperator *B = cast<BinaryOperator>(T); 757 std::string sbuf; 758 llvm::raw_string_ostream os(sbuf); 759 os << "Left side of '"; 760 761 if (B->getOpcode() == BO_LAnd) { 762 os << "&&" << "' is "; 763 764 if (*(Src->succ_begin()+1) == Dst) { 765 os << "false"; 766 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 767 PathDiagnosticLocation Start = 768 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 769 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 770 Start, End, os.str())); 771 } 772 else { 773 os << "true"; 774 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 775 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 776 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 777 Start, End, os.str())); 778 } 779 } 780 else { 781 assert(B->getOpcode() == BO_LOr); 782 os << "||" << "' is "; 783 784 if (*(Src->succ_begin()+1) == Dst) { 785 os << "false"; 786 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 787 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 788 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 789 Start, End, os.str())); 790 } 791 else { 792 os << "true"; 793 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 794 PathDiagnosticLocation Start = 795 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 796 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 797 Start, End, os.str())); 798 } 799 } 800 801 break; 802 } 803 804 case Stmt::DoStmtClass: { 805 if (*(Src->succ_begin()) == Dst) { 806 std::string sbuf; 807 llvm::raw_string_ostream os(sbuf); 808 809 os << "Loop condition is true. "; 810 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 811 812 if (const Stmt *S = End.asStmt()) 813 End = PDB.getEnclosingStmtLocation(S); 814 815 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 816 Start, End, os.str())); 817 } 818 else { 819 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 820 821 if (const Stmt *S = End.asStmt()) 822 End = PDB.getEnclosingStmtLocation(S); 823 824 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 825 Start, End, "Loop condition is false. Exiting loop")); 826 } 827 828 break; 829 } 830 831 case Stmt::WhileStmtClass: 832 case Stmt::ForStmtClass: { 833 if (*(Src->succ_begin()+1) == Dst) { 834 std::string sbuf; 835 llvm::raw_string_ostream os(sbuf); 836 837 os << "Loop condition is false. "; 838 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 839 if (const Stmt *S = End.asStmt()) 840 End = PDB.getEnclosingStmtLocation(S); 841 842 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 843 Start, End, os.str())); 844 } 845 else { 846 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 847 if (const Stmt *S = End.asStmt()) 848 End = PDB.getEnclosingStmtLocation(S); 849 850 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 851 Start, End, "Loop condition is true. Entering loop body")); 852 } 853 854 break; 855 } 856 857 case Stmt::IfStmtClass: { 858 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 859 860 if (const Stmt *S = End.asStmt()) 861 End = PDB.getEnclosingStmtLocation(S); 862 863 if (*(Src->succ_begin()+1) == Dst) 864 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 865 Start, End, "Taking false branch")); 866 else 867 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 868 Start, End, "Taking true branch")); 869 870 break; 871 } 872 } 873 } 874 } while(0); 875 876 if (NextNode) { 877 // Add diagnostic pieces from custom visitors. 878 BugReport *R = PDB.getBugReport(); 879 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 880 E = visitors.end(); 881 I != E; ++I) { 882 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) { 883 PD.getActivePath().push_front(p); 884 updateStackPiecesWithMessage(p, CallStack); 885 } 886 } 887 } 888 } 889 890 if (!PDB.getBugReport()->isValid()) 891 return false; 892 893 // After constructing the full PathDiagnostic, do a pass over it to compact 894 // PathDiagnosticPieces that occur within a macro. 895 CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager()); 896 return true; 897 } 898 899 //===----------------------------------------------------------------------===// 900 // "Extensive" PathDiagnostic generation. 901 //===----------------------------------------------------------------------===// 902 903 static bool IsControlFlowExpr(const Stmt *S) { 904 const Expr *E = dyn_cast<Expr>(S); 905 906 if (!E) 907 return false; 908 909 E = E->IgnoreParenCasts(); 910 911 if (isa<AbstractConditionalOperator>(E)) 912 return true; 913 914 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E)) 915 if (B->isLogicalOp()) 916 return true; 917 918 return false; 919 } 920 921 namespace { 922 class ContextLocation : public PathDiagnosticLocation { 923 bool IsDead; 924 public: 925 ContextLocation(const PathDiagnosticLocation &L, bool isdead = false) 926 : PathDiagnosticLocation(L), IsDead(isdead) {} 927 928 void markDead() { IsDead = true; } 929 bool isDead() const { return IsDead; } 930 }; 931 932 class EdgeBuilder { 933 std::vector<ContextLocation> CLocs; 934 typedef std::vector<ContextLocation>::iterator iterator; 935 PathDiagnostic &PD; 936 PathDiagnosticBuilder &PDB; 937 PathDiagnosticLocation PrevLoc; 938 939 bool IsConsumedExpr(const PathDiagnosticLocation &L); 940 941 bool containsLocation(const PathDiagnosticLocation &Container, 942 const PathDiagnosticLocation &Containee); 943 944 PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L); 945 946 PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L, 947 bool firstCharOnly = false) { 948 if (const Stmt *S = L.asStmt()) { 949 const Stmt *Original = S; 950 while (1) { 951 // Adjust the location for some expressions that are best referenced 952 // by one of their subexpressions. 953 switch (S->getStmtClass()) { 954 default: 955 break; 956 case Stmt::ParenExprClass: 957 case Stmt::GenericSelectionExprClass: 958 S = cast<Expr>(S)->IgnoreParens(); 959 firstCharOnly = true; 960 continue; 961 case Stmt::BinaryConditionalOperatorClass: 962 case Stmt::ConditionalOperatorClass: 963 S = cast<AbstractConditionalOperator>(S)->getCond(); 964 firstCharOnly = true; 965 continue; 966 case Stmt::ChooseExprClass: 967 S = cast<ChooseExpr>(S)->getCond(); 968 firstCharOnly = true; 969 continue; 970 case Stmt::BinaryOperatorClass: 971 S = cast<BinaryOperator>(S)->getLHS(); 972 firstCharOnly = true; 973 continue; 974 } 975 976 break; 977 } 978 979 if (S != Original) 980 L = PathDiagnosticLocation(S, L.getManager(), PDB.LC); 981 } 982 983 if (firstCharOnly) 984 L = PathDiagnosticLocation::createSingleLocation(L); 985 986 return L; 987 } 988 989 void popLocation() { 990 if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) { 991 // For contexts, we only one the first character as the range. 992 rawAddEdge(cleanUpLocation(CLocs.back(), true)); 993 } 994 CLocs.pop_back(); 995 } 996 997 public: 998 EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb) 999 : PD(pd), PDB(pdb) { 1000 1001 // If the PathDiagnostic already has pieces, add the enclosing statement 1002 // of the first piece as a context as well. 1003 if (!PD.path.empty()) { 1004 PrevLoc = (*PD.path.begin())->getLocation(); 1005 1006 if (const Stmt *S = PrevLoc.asStmt()) 1007 addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 1008 } 1009 } 1010 1011 ~EdgeBuilder() { 1012 while (!CLocs.empty()) popLocation(); 1013 1014 // Finally, add an initial edge from the start location of the first 1015 // statement (if it doesn't already exist). 1016 PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin( 1017 PDB.LC, 1018 PDB.getSourceManager()); 1019 if (L.isValid()) 1020 rawAddEdge(L); 1021 } 1022 1023 void flushLocations() { 1024 while (!CLocs.empty()) 1025 popLocation(); 1026 PrevLoc = PathDiagnosticLocation(); 1027 } 1028 1029 void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false); 1030 1031 void rawAddEdge(PathDiagnosticLocation NewLoc); 1032 1033 void addContext(const Stmt *S); 1034 void addContext(const PathDiagnosticLocation &L); 1035 void addExtendedContext(const Stmt *S); 1036 }; 1037 } // end anonymous namespace 1038 1039 1040 PathDiagnosticLocation 1041 EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) { 1042 if (const Stmt *S = L.asStmt()) { 1043 if (IsControlFlowExpr(S)) 1044 return L; 1045 1046 return PDB.getEnclosingStmtLocation(S); 1047 } 1048 1049 return L; 1050 } 1051 1052 bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container, 1053 const PathDiagnosticLocation &Containee) { 1054 1055 if (Container == Containee) 1056 return true; 1057 1058 if (Container.asDecl()) 1059 return true; 1060 1061 if (const Stmt *S = Containee.asStmt()) 1062 if (const Stmt *ContainerS = Container.asStmt()) { 1063 while (S) { 1064 if (S == ContainerS) 1065 return true; 1066 S = PDB.getParent(S); 1067 } 1068 return false; 1069 } 1070 1071 // Less accurate: compare using source ranges. 1072 SourceRange ContainerR = Container.asRange(); 1073 SourceRange ContaineeR = Containee.asRange(); 1074 1075 SourceManager &SM = PDB.getSourceManager(); 1076 SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin()); 1077 SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd()); 1078 SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin()); 1079 SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd()); 1080 1081 unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg); 1082 unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd); 1083 unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg); 1084 unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd); 1085 1086 assert(ContainerBegLine <= ContainerEndLine); 1087 assert(ContaineeBegLine <= ContaineeEndLine); 1088 1089 return (ContainerBegLine <= ContaineeBegLine && 1090 ContainerEndLine >= ContaineeEndLine && 1091 (ContainerBegLine != ContaineeBegLine || 1092 SM.getExpansionColumnNumber(ContainerRBeg) <= 1093 SM.getExpansionColumnNumber(ContaineeRBeg)) && 1094 (ContainerEndLine != ContaineeEndLine || 1095 SM.getExpansionColumnNumber(ContainerREnd) >= 1096 SM.getExpansionColumnNumber(ContaineeREnd))); 1097 } 1098 1099 void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) { 1100 if (!PrevLoc.isValid()) { 1101 PrevLoc = NewLoc; 1102 return; 1103 } 1104 1105 const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc); 1106 const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc); 1107 1108 if (PrevLocClean.asLocation().isInvalid()) { 1109 PrevLoc = NewLoc; 1110 return; 1111 } 1112 1113 if (NewLocClean.asLocation() == PrevLocClean.asLocation()) 1114 return; 1115 1116 // FIXME: Ignore intra-macro edges for now. 1117 if (NewLocClean.asLocation().getExpansionLoc() == 1118 PrevLocClean.asLocation().getExpansionLoc()) 1119 return; 1120 1121 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean)); 1122 PrevLoc = NewLoc; 1123 } 1124 1125 void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd) { 1126 1127 if (!alwaysAdd && NewLoc.asLocation().isMacroID()) 1128 return; 1129 1130 const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc); 1131 1132 while (!CLocs.empty()) { 1133 ContextLocation &TopContextLoc = CLocs.back(); 1134 1135 // Is the top location context the same as the one for the new location? 1136 if (TopContextLoc == CLoc) { 1137 if (alwaysAdd) { 1138 if (IsConsumedExpr(TopContextLoc) && 1139 !IsControlFlowExpr(TopContextLoc.asStmt())) 1140 TopContextLoc.markDead(); 1141 1142 rawAddEdge(NewLoc); 1143 } 1144 1145 return; 1146 } 1147 1148 if (containsLocation(TopContextLoc, CLoc)) { 1149 if (alwaysAdd) { 1150 rawAddEdge(NewLoc); 1151 1152 if (IsConsumedExpr(CLoc) && !IsControlFlowExpr(CLoc.asStmt())) { 1153 CLocs.push_back(ContextLocation(CLoc, true)); 1154 return; 1155 } 1156 } 1157 1158 CLocs.push_back(CLoc); 1159 return; 1160 } 1161 1162 // Context does not contain the location. Flush it. 1163 popLocation(); 1164 } 1165 1166 // If we reach here, there is no enclosing context. Just add the edge. 1167 rawAddEdge(NewLoc); 1168 } 1169 1170 bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) { 1171 if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt())) 1172 return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X); 1173 1174 return false; 1175 } 1176 1177 void EdgeBuilder::addExtendedContext(const Stmt *S) { 1178 if (!S) 1179 return; 1180 1181 const Stmt *Parent = PDB.getParent(S); 1182 while (Parent) { 1183 if (isa<CompoundStmt>(Parent)) 1184 Parent = PDB.getParent(Parent); 1185 else 1186 break; 1187 } 1188 1189 if (Parent) { 1190 switch (Parent->getStmtClass()) { 1191 case Stmt::DoStmtClass: 1192 case Stmt::ObjCAtSynchronizedStmtClass: 1193 addContext(Parent); 1194 default: 1195 break; 1196 } 1197 } 1198 1199 addContext(S); 1200 } 1201 1202 void EdgeBuilder::addContext(const Stmt *S) { 1203 if (!S) 1204 return; 1205 1206 PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC); 1207 addContext(L); 1208 } 1209 1210 void EdgeBuilder::addContext(const PathDiagnosticLocation &L) { 1211 while (!CLocs.empty()) { 1212 const PathDiagnosticLocation &TopContextLoc = CLocs.back(); 1213 1214 // Is the top location context the same as the one for the new location? 1215 if (TopContextLoc == L) 1216 return; 1217 1218 if (containsLocation(TopContextLoc, L)) { 1219 CLocs.push_back(L); 1220 return; 1221 } 1222 1223 // Context does not contain the location. Flush it. 1224 popLocation(); 1225 } 1226 1227 CLocs.push_back(L); 1228 } 1229 1230 // Cone-of-influence: support the reverse propagation of "interesting" symbols 1231 // and values by tracing interesting calculations backwards through evaluated 1232 // expressions along a path. This is probably overly complicated, but the idea 1233 // is that if an expression computed an "interesting" value, the child 1234 // expressions are are also likely to be "interesting" as well (which then 1235 // propagates to the values they in turn compute). This reverse propagation 1236 // is needed to track interesting correlations across function call boundaries, 1237 // where formal arguments bind to actual arguments, etc. This is also needed 1238 // because the constraint solver sometimes simplifies certain symbolic values 1239 // into constants when appropriate, and this complicates reasoning about 1240 // interesting values. 1241 typedef llvm::DenseSet<const Expr *> InterestingExprs; 1242 1243 static void reversePropagateIntererstingSymbols(BugReport &R, 1244 InterestingExprs &IE, 1245 const ProgramState *State, 1246 const Expr *Ex, 1247 const LocationContext *LCtx) { 1248 SVal V = State->getSVal(Ex, LCtx); 1249 if (!(R.isInteresting(V) || IE.count(Ex))) 1250 return; 1251 1252 switch (Ex->getStmtClass()) { 1253 default: 1254 if (!isa<CastExpr>(Ex)) 1255 break; 1256 // Fall through. 1257 case Stmt::BinaryOperatorClass: 1258 case Stmt::UnaryOperatorClass: { 1259 for (Stmt::const_child_iterator CI = Ex->child_begin(), 1260 CE = Ex->child_end(); 1261 CI != CE; ++CI) { 1262 if (const Expr *child = dyn_cast_or_null<Expr>(*CI)) { 1263 IE.insert(child); 1264 SVal ChildV = State->getSVal(child, LCtx); 1265 R.markInteresting(ChildV); 1266 } 1267 break; 1268 } 1269 } 1270 } 1271 1272 R.markInteresting(V); 1273 } 1274 1275 static void reversePropagateInterestingSymbols(BugReport &R, 1276 InterestingExprs &IE, 1277 const ProgramState *State, 1278 const LocationContext *CalleeCtx, 1279 const LocationContext *CallerCtx) 1280 { 1281 // FIXME: Handle non-CallExpr-based CallEvents. 1282 const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame(); 1283 const Stmt *CallSite = Callee->getCallSite(); 1284 if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) { 1285 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) { 1286 FunctionDecl::param_const_iterator PI = FD->param_begin(), 1287 PE = FD->param_end(); 1288 CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end(); 1289 for (; AI != AE && PI != PE; ++AI, ++PI) { 1290 if (const Expr *ArgE = *AI) { 1291 if (const ParmVarDecl *PD = *PI) { 1292 Loc LV = State->getLValue(PD, CalleeCtx); 1293 if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV))) 1294 IE.insert(ArgE); 1295 } 1296 } 1297 } 1298 } 1299 } 1300 } 1301 1302 //===----------------------------------------------------------------------===// 1303 // Functions for determining if a loop was executed 0 times. 1304 //===----------------------------------------------------------------------===// 1305 1306 /// Return true if the terminator is a loop and the destination is the 1307 /// false branch. 1308 static bool isLoopJumpPastBody(const Stmt *Term, const BlockEdge *BE) { 1309 switch (Term->getStmtClass()) { 1310 case Stmt::ForStmtClass: 1311 case Stmt::WhileStmtClass: 1312 case Stmt::ObjCForCollectionStmtClass: 1313 break; 1314 default: 1315 // Note that we intentionally do not include do..while here. 1316 return false; 1317 } 1318 1319 // Did we take the false branch? 1320 const CFGBlock *Src = BE->getSrc(); 1321 assert(Src->succ_size() == 2); 1322 return (*(Src->succ_begin()+1) == BE->getDst()); 1323 } 1324 1325 static bool isContainedByStmt(ParentMap &PM, const Stmt *S, const Stmt *SubS) { 1326 while (SubS) { 1327 if (SubS == S) 1328 return true; 1329 SubS = PM.getParent(SubS); 1330 } 1331 return false; 1332 } 1333 1334 static const Stmt *getStmtBeforeCond(ParentMap &PM, const Stmt *Term, 1335 const ExplodedNode *N) { 1336 while (N) { 1337 Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>(); 1338 if (SP) { 1339 const Stmt *S = SP->getStmt(); 1340 if (!isContainedByStmt(PM, Term, S)) 1341 return S; 1342 } 1343 N = GetPredecessorNode(N); 1344 } 1345 return 0; 1346 } 1347 1348 static bool isInLoopBody(ParentMap &PM, const Stmt *S, const Stmt *Term) { 1349 const Stmt *LoopBody = 0; 1350 switch (Term->getStmtClass()) { 1351 case Stmt::ForStmtClass: { 1352 const ForStmt *FS = cast<ForStmt>(Term); 1353 if (isContainedByStmt(PM, FS->getInc(), S)) 1354 return true; 1355 LoopBody = FS->getBody(); 1356 break; 1357 } 1358 case Stmt::ObjCForCollectionStmtClass: { 1359 const ObjCForCollectionStmt *FC = cast<ObjCForCollectionStmt>(Term); 1360 LoopBody = FC->getBody(); 1361 break; 1362 } 1363 case Stmt::WhileStmtClass: 1364 LoopBody = cast<WhileStmt>(Term)->getBody(); 1365 break; 1366 default: 1367 return false; 1368 } 1369 return isContainedByStmt(PM, LoopBody, S); 1370 } 1371 1372 //===----------------------------------------------------------------------===// 1373 // Top-level logic for generating extensive path diagnostics. 1374 //===----------------------------------------------------------------------===// 1375 1376 static bool GenerateExtensivePathDiagnostic(PathDiagnostic& PD, 1377 PathDiagnosticBuilder &PDB, 1378 const ExplodedNode *N, 1379 ArrayRef<BugReporterVisitor *> visitors) { 1380 EdgeBuilder EB(PD, PDB); 1381 const SourceManager& SM = PDB.getSourceManager(); 1382 StackDiagVector CallStack; 1383 InterestingExprs IE; 1384 1385 const ExplodedNode *NextNode = N->pred_empty() ? NULL : *(N->pred_begin()); 1386 while (NextNode) { 1387 N = NextNode; 1388 NextNode = GetPredecessorNode(N); 1389 ProgramPoint P = N->getLocation(); 1390 1391 do { 1392 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1393 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1394 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1395 N->getState().getPtr(), Ex, 1396 N->getLocationContext()); 1397 } 1398 1399 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1400 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1401 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1402 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1403 N->getState().getPtr(), Ex, 1404 N->getLocationContext()); 1405 } 1406 1407 PathDiagnosticCallPiece *C = 1408 PathDiagnosticCallPiece::construct(N, *CE, SM); 1409 GRBugReporter& BR = PDB.getBugReporter(); 1410 BR.addCallPieceLocationContextPair(C, CE->getCalleeContext()); 1411 1412 EB.addEdge(C->callReturn, true); 1413 EB.flushLocations(); 1414 1415 PD.getActivePath().push_front(C); 1416 PD.pushActivePath(&C->path); 1417 CallStack.push_back(StackDiagPair(C, N)); 1418 break; 1419 } 1420 1421 // Pop the call hierarchy if we are done walking the contents 1422 // of a function call. 1423 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1424 // Add an edge to the start of the function. 1425 const Decl *D = CE->getCalleeContext()->getDecl(); 1426 PathDiagnosticLocation pos = 1427 PathDiagnosticLocation::createBegin(D, SM); 1428 EB.addEdge(pos); 1429 1430 // Flush all locations, and pop the active path. 1431 bool VisitedEntireCall = PD.isWithinCall(); 1432 EB.flushLocations(); 1433 PD.popActivePath(); 1434 PDB.LC = N->getLocationContext(); 1435 1436 // Either we just added a bunch of stuff to the top-level path, or 1437 // we have a previous CallExitEnd. If the former, it means that the 1438 // path terminated within a function call. We must then take the 1439 // current contents of the active path and place it within 1440 // a new PathDiagnosticCallPiece. 1441 PathDiagnosticCallPiece *C; 1442 if (VisitedEntireCall) { 1443 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 1444 } else { 1445 const Decl *Caller = CE->getLocationContext()->getDecl(); 1446 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1447 GRBugReporter& BR = PDB.getBugReporter(); 1448 BR.addCallPieceLocationContextPair(C, CE->getCalleeContext()); 1449 } 1450 1451 C->setCallee(*CE, SM); 1452 EB.addContext(C->getLocation()); 1453 1454 if (!CallStack.empty()) { 1455 assert(CallStack.back().first == C); 1456 CallStack.pop_back(); 1457 } 1458 break; 1459 } 1460 1461 // Note that is important that we update the LocationContext 1462 // after looking at CallExits. CallExit basically adds an 1463 // edge in the *caller*, so we don't want to update the LocationContext 1464 // too soon. 1465 PDB.LC = N->getLocationContext(); 1466 1467 // Block edges. 1468 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1469 // Does this represent entering a call? If so, look at propagating 1470 // interesting symbols across call boundaries. 1471 if (NextNode) { 1472 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1473 const LocationContext *CalleeCtx = PDB.LC; 1474 if (CallerCtx != CalleeCtx) { 1475 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1476 N->getState().getPtr(), 1477 CalleeCtx, CallerCtx); 1478 } 1479 } 1480 1481 // Are we jumping to the head of a loop? Add a special diagnostic. 1482 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1483 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1484 const CompoundStmt *CS = NULL; 1485 1486 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1487 CS = dyn_cast<CompoundStmt>(FS->getBody()); 1488 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1489 CS = dyn_cast<CompoundStmt>(WS->getBody()); 1490 1491 PathDiagnosticEventPiece *p = 1492 new PathDiagnosticEventPiece(L, 1493 "Looping back to the head of the loop"); 1494 p->setPrunable(true); 1495 1496 EB.addEdge(p->getLocation(), true); 1497 PD.getActivePath().push_front(p); 1498 1499 if (CS) { 1500 PathDiagnosticLocation BL = 1501 PathDiagnosticLocation::createEndBrace(CS, SM); 1502 EB.addEdge(BL); 1503 } 1504 } 1505 1506 const CFGBlock *BSrc = BE->getSrc(); 1507 ParentMap &PM = PDB.getParentMap(); 1508 1509 if (const Stmt *Term = BSrc->getTerminator()) { 1510 // Are we jumping past the loop body without ever executing the 1511 // loop (because the condition was false)? 1512 if (isLoopJumpPastBody(Term, &*BE) && 1513 !isInLoopBody(PM, 1514 getStmtBeforeCond(PM, 1515 BSrc->getTerminatorCondition(), 1516 N), 1517 Term)) { 1518 PathDiagnosticLocation L(Term, SM, PDB.LC); 1519 PathDiagnosticEventPiece *PE = 1520 new PathDiagnosticEventPiece(L, "Loop body executed 0 times"); 1521 PE->setPrunable(true); 1522 1523 EB.addEdge(PE->getLocation(), true); 1524 PD.getActivePath().push_front(PE); 1525 } 1526 1527 // In any case, add the terminator as the current statement 1528 // context for control edges. 1529 EB.addContext(Term); 1530 } 1531 1532 break; 1533 } 1534 1535 if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) { 1536 Optional<CFGElement> First = BE->getFirstElement(); 1537 if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) { 1538 const Stmt *stmt = S->getStmt(); 1539 if (IsControlFlowExpr(stmt)) { 1540 // Add the proper context for '&&', '||', and '?'. 1541 EB.addContext(stmt); 1542 } 1543 else 1544 EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt()); 1545 } 1546 1547 break; 1548 } 1549 1550 1551 } while (0); 1552 1553 if (!NextNode) 1554 continue; 1555 1556 // Add pieces from custom visitors. 1557 BugReport *R = PDB.getBugReport(); 1558 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 1559 E = visitors.end(); 1560 I != E; ++I) { 1561 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) { 1562 const PathDiagnosticLocation &Loc = p->getLocation(); 1563 EB.addEdge(Loc, true); 1564 PD.getActivePath().push_front(p); 1565 updateStackPiecesWithMessage(p, CallStack); 1566 1567 if (const Stmt *S = Loc.asStmt()) 1568 EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 1569 } 1570 } 1571 } 1572 1573 return PDB.getBugReport()->isValid(); 1574 } 1575 1576 //===----------------------------------------------------------------------===// 1577 // Methods for BugType and subclasses. 1578 //===----------------------------------------------------------------------===// 1579 BugType::~BugType() { } 1580 1581 void BugType::FlushReports(BugReporter &BR) {} 1582 1583 void BuiltinBug::anchor() {} 1584 1585 //===----------------------------------------------------------------------===// 1586 // Methods for BugReport and subclasses. 1587 //===----------------------------------------------------------------------===// 1588 1589 void BugReport::NodeResolver::anchor() {} 1590 1591 void BugReport::addVisitor(BugReporterVisitor* visitor) { 1592 if (!visitor) 1593 return; 1594 1595 llvm::FoldingSetNodeID ID; 1596 visitor->Profile(ID); 1597 void *InsertPos; 1598 1599 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) { 1600 delete visitor; 1601 return; 1602 } 1603 1604 CallbacksSet.InsertNode(visitor, InsertPos); 1605 Callbacks.push_back(visitor); 1606 ++ConfigurationChangeToken; 1607 } 1608 1609 BugReport::~BugReport() { 1610 for (visitor_iterator I = visitor_begin(), E = visitor_end(); I != E; ++I) { 1611 delete *I; 1612 } 1613 while (!interestingSymbols.empty()) { 1614 popInterestingSymbolsAndRegions(); 1615 } 1616 } 1617 1618 const Decl *BugReport::getDeclWithIssue() const { 1619 if (DeclWithIssue) 1620 return DeclWithIssue; 1621 1622 const ExplodedNode *N = getErrorNode(); 1623 if (!N) 1624 return 0; 1625 1626 const LocationContext *LC = N->getLocationContext(); 1627 return LC->getCurrentStackFrame()->getDecl(); 1628 } 1629 1630 void BugReport::Profile(llvm::FoldingSetNodeID& hash) const { 1631 hash.AddPointer(&BT); 1632 hash.AddString(Description); 1633 PathDiagnosticLocation UL = getUniqueingLocation(); 1634 if (UL.isValid()) { 1635 UL.Profile(hash); 1636 } else if (Location.isValid()) { 1637 Location.Profile(hash); 1638 } else { 1639 assert(ErrorNode); 1640 hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode)); 1641 } 1642 1643 for (SmallVectorImpl<SourceRange>::const_iterator I = 1644 Ranges.begin(), E = Ranges.end(); I != E; ++I) { 1645 const SourceRange range = *I; 1646 if (!range.isValid()) 1647 continue; 1648 hash.AddInteger(range.getBegin().getRawEncoding()); 1649 hash.AddInteger(range.getEnd().getRawEncoding()); 1650 } 1651 } 1652 1653 void BugReport::markInteresting(SymbolRef sym) { 1654 if (!sym) 1655 return; 1656 1657 // If the symbol wasn't already in our set, note a configuration change. 1658 if (getInterestingSymbols().insert(sym).second) 1659 ++ConfigurationChangeToken; 1660 1661 if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym)) 1662 getInterestingRegions().insert(meta->getRegion()); 1663 } 1664 1665 void BugReport::markInteresting(const MemRegion *R) { 1666 if (!R) 1667 return; 1668 1669 // If the base region wasn't already in our set, note a configuration change. 1670 R = R->getBaseRegion(); 1671 if (getInterestingRegions().insert(R).second) 1672 ++ConfigurationChangeToken; 1673 1674 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1675 getInterestingSymbols().insert(SR->getSymbol()); 1676 } 1677 1678 void BugReport::markInteresting(SVal V) { 1679 markInteresting(V.getAsRegion()); 1680 markInteresting(V.getAsSymbol()); 1681 } 1682 1683 void BugReport::markInteresting(const LocationContext *LC) { 1684 if (!LC) 1685 return; 1686 InterestingLocationContexts.insert(LC); 1687 } 1688 1689 bool BugReport::isInteresting(SVal V) { 1690 return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol()); 1691 } 1692 1693 bool BugReport::isInteresting(SymbolRef sym) { 1694 if (!sym) 1695 return false; 1696 // We don't currently consider metadata symbols to be interesting 1697 // even if we know their region is interesting. Is that correct behavior? 1698 return getInterestingSymbols().count(sym); 1699 } 1700 1701 bool BugReport::isInteresting(const MemRegion *R) { 1702 if (!R) 1703 return false; 1704 R = R->getBaseRegion(); 1705 bool b = getInterestingRegions().count(R); 1706 if (b) 1707 return true; 1708 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1709 return getInterestingSymbols().count(SR->getSymbol()); 1710 return false; 1711 } 1712 1713 bool BugReport::isInteresting(const LocationContext *LC) { 1714 if (!LC) 1715 return false; 1716 return InterestingLocationContexts.count(LC); 1717 } 1718 1719 void BugReport::lazyInitializeInterestingSets() { 1720 if (interestingSymbols.empty()) { 1721 interestingSymbols.push_back(new Symbols()); 1722 interestingRegions.push_back(new Regions()); 1723 } 1724 } 1725 1726 BugReport::Symbols &BugReport::getInterestingSymbols() { 1727 lazyInitializeInterestingSets(); 1728 return *interestingSymbols.back(); 1729 } 1730 1731 BugReport::Regions &BugReport::getInterestingRegions() { 1732 lazyInitializeInterestingSets(); 1733 return *interestingRegions.back(); 1734 } 1735 1736 void BugReport::pushInterestingSymbolsAndRegions() { 1737 interestingSymbols.push_back(new Symbols(getInterestingSymbols())); 1738 interestingRegions.push_back(new Regions(getInterestingRegions())); 1739 } 1740 1741 void BugReport::popInterestingSymbolsAndRegions() { 1742 delete interestingSymbols.back(); 1743 interestingSymbols.pop_back(); 1744 delete interestingRegions.back(); 1745 interestingRegions.pop_back(); 1746 } 1747 1748 const Stmt *BugReport::getStmt() const { 1749 if (!ErrorNode) 1750 return 0; 1751 1752 ProgramPoint ProgP = ErrorNode->getLocation(); 1753 const Stmt *S = NULL; 1754 1755 if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) { 1756 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit(); 1757 if (BE->getBlock() == &Exit) 1758 S = GetPreviousStmt(ErrorNode); 1759 } 1760 if (!S) 1761 S = GetStmt(ProgP); 1762 1763 return S; 1764 } 1765 1766 std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator> 1767 BugReport::getRanges() { 1768 // If no custom ranges, add the range of the statement corresponding to 1769 // the error node. 1770 if (Ranges.empty()) { 1771 if (const Expr *E = dyn_cast_or_null<Expr>(getStmt())) 1772 addRange(E->getSourceRange()); 1773 else 1774 return std::make_pair(ranges_iterator(), ranges_iterator()); 1775 } 1776 1777 // User-specified absence of range info. 1778 if (Ranges.size() == 1 && !Ranges.begin()->isValid()) 1779 return std::make_pair(ranges_iterator(), ranges_iterator()); 1780 1781 return std::make_pair(Ranges.begin(), Ranges.end()); 1782 } 1783 1784 PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const { 1785 if (ErrorNode) { 1786 assert(!Location.isValid() && 1787 "Either Location or ErrorNode should be specified but not both."); 1788 1789 if (const Stmt *S = GetCurrentOrPreviousStmt(ErrorNode)) { 1790 const LocationContext *LC = ErrorNode->getLocationContext(); 1791 1792 // For member expressions, return the location of the '.' or '->'. 1793 if (const MemberExpr *ME = dyn_cast<MemberExpr>(S)) 1794 return PathDiagnosticLocation::createMemberLoc(ME, SM); 1795 // For binary operators, return the location of the operator. 1796 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(S)) 1797 return PathDiagnosticLocation::createOperatorLoc(B, SM); 1798 1799 if (ErrorNode->getLocation().getAs<PostStmtPurgeDeadSymbols>()) 1800 return PathDiagnosticLocation::createEnd(S, SM, LC); 1801 1802 return PathDiagnosticLocation::createBegin(S, SM, LC); 1803 } 1804 } else { 1805 assert(Location.isValid()); 1806 return Location; 1807 } 1808 1809 return PathDiagnosticLocation(); 1810 } 1811 1812 //===----------------------------------------------------------------------===// 1813 // Methods for BugReporter and subclasses. 1814 //===----------------------------------------------------------------------===// 1815 1816 BugReportEquivClass::~BugReportEquivClass() { } 1817 GRBugReporter::~GRBugReporter() { } 1818 BugReporterData::~BugReporterData() {} 1819 1820 ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); } 1821 1822 ProgramStateManager& 1823 GRBugReporter::getStateManager() { return Eng.getStateManager(); } 1824 1825 BugReporter::~BugReporter() { 1826 FlushReports(); 1827 1828 // Free the bug reports we are tracking. 1829 typedef std::vector<BugReportEquivClass *> ContTy; 1830 for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end(); 1831 I != E; ++I) { 1832 delete *I; 1833 } 1834 } 1835 1836 void BugReporter::FlushReports() { 1837 if (BugTypes.isEmpty()) 1838 return; 1839 1840 // First flush the warnings for each BugType. This may end up creating new 1841 // warnings and new BugTypes. 1842 // FIXME: Only NSErrorChecker needs BugType's FlushReports. 1843 // Turn NSErrorChecker into a proper checker and remove this. 1844 SmallVector<const BugType*, 16> bugTypes; 1845 for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I) 1846 bugTypes.push_back(*I); 1847 for (SmallVector<const BugType*, 16>::iterator 1848 I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I) 1849 const_cast<BugType*>(*I)->FlushReports(*this); 1850 1851 // We need to flush reports in deterministic order to ensure the order 1852 // of the reports is consistent between runs. 1853 typedef std::vector<BugReportEquivClass *> ContVecTy; 1854 for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end(); 1855 EI != EE; ++EI){ 1856 BugReportEquivClass& EQ = **EI; 1857 FlushReport(EQ); 1858 } 1859 1860 // BugReporter owns and deletes only BugTypes created implicitly through 1861 // EmitBasicReport. 1862 // FIXME: There are leaks from checkers that assume that the BugTypes they 1863 // create will be destroyed by the BugReporter. 1864 for (llvm::StringMap<BugType*>::iterator 1865 I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I) 1866 delete I->second; 1867 1868 // Remove all references to the BugType objects. 1869 BugTypes = F.getEmptySet(); 1870 } 1871 1872 //===----------------------------------------------------------------------===// 1873 // PathDiagnostics generation. 1874 //===----------------------------------------------------------------------===// 1875 1876 namespace { 1877 /// A wrapper around a report graph, which contains only a single path, and its 1878 /// node maps. 1879 class ReportGraph { 1880 public: 1881 OwningPtr<ExplodedGraph> Graph; 1882 InterExplodedGraphMap BackMap; 1883 ExplodedNode *ErrorNode; 1884 size_t Index; 1885 }; 1886 1887 /// A wrapper around a trimmed graph and its node maps. 1888 class TrimmedGraph { 1889 InterExplodedGraphMap ForwardMap; 1890 InterExplodedGraphMap InverseMap; 1891 OwningPtr<ExplodedGraph> G; 1892 public: 1893 /// 1894 TrimmedGraph(const ExplodedGraph *OriginalGraph, 1895 ArrayRef<const ExplodedNode *> Nodes) { 1896 // The trimmed graph is created in the body of the constructor to ensure 1897 // that the DenseMaps have been initialized already. 1898 G.reset(OriginalGraph->trim(Nodes, &ForwardMap, &InverseMap)); 1899 } 1900 1901 void createBestReportGraph(ArrayRef<const ExplodedNode *> Nodes, 1902 ReportGraph &GraphWrapper) const; 1903 }; 1904 1905 } 1906 1907 1908 void TrimmedGraph::createBestReportGraph(ArrayRef<const ExplodedNode *> Nodes, 1909 ReportGraph &GraphWrapper) const { 1910 assert(!GraphWrapper.Graph && "ReportGraph is already in use"); 1911 assert(GraphWrapper.BackMap.empty() && "ReportGraph is already in use"); 1912 1913 // Find the (first) error node in the trimmed graph. We just need to consult 1914 // the node map which maps from nodes in the original graph to nodes 1915 // in the new graph. 1916 std::queue<const ExplodedNode *> WS; 1917 typedef llvm::SmallDenseMap<const ExplodedNode *, size_t, 32> IndexMapTy; 1918 IndexMapTy IndexMap; 1919 1920 for (unsigned i = 0, count = Nodes.size(); i < count; ++i) { 1921 const ExplodedNode *OriginalNode = Nodes[i]; 1922 if (const ExplodedNode *N = ForwardMap.lookup(OriginalNode)) { 1923 WS.push(N); 1924 IndexMap[OriginalNode] = i; 1925 } 1926 } 1927 1928 assert(!WS.empty() && "No error node found in the trimmed graph."); 1929 1930 // Create a new graph with a single path. This is the graph 1931 // that will be returned to the caller. 1932 ExplodedGraph *GNew = new ExplodedGraph(); 1933 GraphWrapper.Graph.reset(GNew); 1934 1935 // Sometimes the trimmed graph can contain a cycle. Perform a reverse BFS 1936 // to the root node, and then construct a new graph that contains only 1937 // a single path. 1938 llvm::DenseMap<const ExplodedNode *, unsigned> Visited; 1939 1940 unsigned cnt = 0; 1941 const ExplodedNode *Root = 0; 1942 1943 while (!WS.empty()) { 1944 const ExplodedNode *Node = WS.front(); 1945 WS.pop(); 1946 1947 if (Visited.find(Node) != Visited.end()) 1948 continue; 1949 1950 Visited[Node] = cnt++; 1951 1952 if (Node->pred_empty()) { 1953 Root = Node; 1954 break; 1955 } 1956 1957 for (ExplodedNode::const_pred_iterator I=Node->pred_begin(), 1958 E=Node->pred_end(); I!=E; ++I) 1959 WS.push(*I); 1960 } 1961 1962 assert(Root); 1963 1964 // Now walk from the root down the BFS path, always taking the successor 1965 // with the lowest number. 1966 ExplodedNode *Last = 0; 1967 for ( const ExplodedNode *N = Root ;;) { 1968 // Lookup the number associated with the current node. 1969 llvm::DenseMap<const ExplodedNode *,unsigned>::iterator I = Visited.find(N); 1970 assert(I != Visited.end()); 1971 1972 // Create the equivalent node in the new graph with the same state 1973 // and location. 1974 ExplodedNode *NewN = GNew->getNode(N->getLocation(), N->getState()); 1975 1976 // Store the mapping to the original node. 1977 InterExplodedGraphMap::const_iterator IMitr = InverseMap.find(N); 1978 assert(IMitr != InverseMap.end() && "No mapping to original node."); 1979 GraphWrapper.BackMap[NewN] = IMitr->second; 1980 1981 // Link up the new node with the previous node. 1982 if (Last) 1983 NewN->addPredecessor(Last, *GNew); 1984 1985 Last = NewN; 1986 1987 // Are we at the final node? 1988 IndexMapTy::iterator IMI = IndexMap.find(IMitr->second); 1989 if (IMI != IndexMap.end()) { 1990 GraphWrapper.ErrorNode = NewN; 1991 GraphWrapper.Index = IMI->second; 1992 break; 1993 } 1994 1995 // Find the next successor node. We choose the node that is marked 1996 // with the lowest DFS number. 1997 unsigned MinVal = -1U; 1998 for (ExplodedNode::const_succ_iterator SI = N->succ_begin(), 1999 SE = N->succ_end(); 2000 SI != SE; ++SI) { 2001 I = Visited.find(*SI); 2002 2003 if (I == Visited.end()) 2004 continue; 2005 2006 if (I->second < MinVal) { 2007 N = *SI; 2008 MinVal = I->second; 2009 } 2010 } 2011 2012 assert(MinVal != -1U); 2013 } 2014 } 2015 2016 /// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object 2017 /// and collapses PathDiagosticPieces that are expanded by macros. 2018 static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) { 2019 typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>, 2020 SourceLocation> > MacroStackTy; 2021 2022 typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> > 2023 PiecesTy; 2024 2025 MacroStackTy MacroStack; 2026 PiecesTy Pieces; 2027 2028 for (PathPieces::const_iterator I = path.begin(), E = path.end(); 2029 I!=E; ++I) { 2030 2031 PathDiagnosticPiece *piece = I->getPtr(); 2032 2033 // Recursively compact calls. 2034 if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){ 2035 CompactPathDiagnostic(call->path, SM); 2036 } 2037 2038 // Get the location of the PathDiagnosticPiece. 2039 const FullSourceLoc Loc = piece->getLocation().asLocation(); 2040 2041 // Determine the instantiation location, which is the location we group 2042 // related PathDiagnosticPieces. 2043 SourceLocation InstantiationLoc = Loc.isMacroID() ? 2044 SM.getExpansionLoc(Loc) : 2045 SourceLocation(); 2046 2047 if (Loc.isFileID()) { 2048 MacroStack.clear(); 2049 Pieces.push_back(piece); 2050 continue; 2051 } 2052 2053 assert(Loc.isMacroID()); 2054 2055 // Is the PathDiagnosticPiece within the same macro group? 2056 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) { 2057 MacroStack.back().first->subPieces.push_back(piece); 2058 continue; 2059 } 2060 2061 // We aren't in the same group. Are we descending into a new macro 2062 // or are part of an old one? 2063 IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup; 2064 2065 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ? 2066 SM.getExpansionLoc(Loc) : 2067 SourceLocation(); 2068 2069 // Walk the entire macro stack. 2070 while (!MacroStack.empty()) { 2071 if (InstantiationLoc == MacroStack.back().second) { 2072 MacroGroup = MacroStack.back().first; 2073 break; 2074 } 2075 2076 if (ParentInstantiationLoc == MacroStack.back().second) { 2077 MacroGroup = MacroStack.back().first; 2078 break; 2079 } 2080 2081 MacroStack.pop_back(); 2082 } 2083 2084 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) { 2085 // Create a new macro group and add it to the stack. 2086 PathDiagnosticMacroPiece *NewGroup = 2087 new PathDiagnosticMacroPiece( 2088 PathDiagnosticLocation::createSingleLocation(piece->getLocation())); 2089 2090 if (MacroGroup) 2091 MacroGroup->subPieces.push_back(NewGroup); 2092 else { 2093 assert(InstantiationLoc.isFileID()); 2094 Pieces.push_back(NewGroup); 2095 } 2096 2097 MacroGroup = NewGroup; 2098 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc)); 2099 } 2100 2101 // Finally, add the PathDiagnosticPiece to the group. 2102 MacroGroup->subPieces.push_back(piece); 2103 } 2104 2105 // Now take the pieces and construct a new PathDiagnostic. 2106 path.clear(); 2107 2108 for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I) 2109 path.push_back(*I); 2110 } 2111 2112 bool GRBugReporter::generatePathDiagnostic(PathDiagnostic& PD, 2113 PathDiagnosticConsumer &PC, 2114 ArrayRef<BugReport *> &bugReports) { 2115 assert(!bugReports.empty()); 2116 2117 bool HasValid = false; 2118 SmallVector<const ExplodedNode *, 32> errorNodes; 2119 for (ArrayRef<BugReport*>::iterator I = bugReports.begin(), 2120 E = bugReports.end(); I != E; ++I) { 2121 if ((*I)->isValid()) { 2122 HasValid = true; 2123 errorNodes.push_back((*I)->getErrorNode()); 2124 } else { 2125 errorNodes.push_back(0); 2126 } 2127 } 2128 2129 // If all the reports have been marked invalid by a previous path generation, 2130 // we're done. 2131 if (!HasValid) 2132 return false; 2133 2134 typedef PathDiagnosticConsumer::PathGenerationScheme PathGenerationScheme; 2135 PathGenerationScheme ActiveScheme = PC.getGenerationScheme(); 2136 2137 TrimmedGraph TrimG(&getGraph(), errorNodes); 2138 2139 for (size_t Remaining = bugReports.size(); Remaining > 0; --Remaining) { 2140 // Construct a new graph that contains only a single path from the error 2141 // node to a root. 2142 ReportGraph ErrorGraph; 2143 TrimG.createBestReportGraph(errorNodes, ErrorGraph); 2144 2145 // Find the BugReport with the original location. 2146 assert(ErrorGraph.Index < bugReports.size()); 2147 BugReport *R = bugReports[ErrorGraph.Index]; 2148 assert(R && "No original report found for sliced graph."); 2149 assert(R->isValid() && "Report selected by trimmed graph marked invalid."); 2150 2151 // Don't try to reuse this report if it ends up being suppressed. 2152 errorNodes[ErrorGraph.Index] = 0; 2153 2154 // Start building the path diagnostic... 2155 PathDiagnosticBuilder PDB(*this, R, ErrorGraph.BackMap, &PC); 2156 const ExplodedNode *N = ErrorGraph.ErrorNode; 2157 2158 // Register additional node visitors. 2159 R->addVisitor(new NilReceiverBRVisitor()); 2160 R->addVisitor(new ConditionBRVisitor()); 2161 R->addVisitor(new LikelyFalsePositiveSuppressionBRVisitor()); 2162 2163 BugReport::VisitorList visitors; 2164 unsigned origReportConfigToken, finalReportConfigToken; 2165 2166 // While generating diagnostics, it's possible the visitors will decide 2167 // new symbols and regions are interesting, or add other visitors based on 2168 // the information they find. If they do, we need to regenerate the path 2169 // based on our new report configuration. 2170 do { 2171 // Get a clean copy of all the visitors. 2172 for (BugReport::visitor_iterator I = R->visitor_begin(), 2173 E = R->visitor_end(); I != E; ++I) 2174 visitors.push_back((*I)->clone()); 2175 2176 // Clear out the active path from any previous work. 2177 PD.resetPath(); 2178 origReportConfigToken = R->getConfigurationChangeToken(); 2179 2180 // Generate the very last diagnostic piece - the piece is visible before 2181 // the trace is expanded. 2182 PathDiagnosticPiece *LastPiece = 0; 2183 for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end(); 2184 I != E; ++I) { 2185 if (PathDiagnosticPiece *Piece = (*I)->getEndPath(PDB, N, *R)) { 2186 assert (!LastPiece && 2187 "There can only be one final piece in a diagnostic."); 2188 LastPiece = Piece; 2189 } 2190 } 2191 2192 if (ActiveScheme != PathDiagnosticConsumer::None) { 2193 if (!LastPiece) 2194 LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R); 2195 assert(LastPiece); 2196 PD.setEndOfPath(LastPiece); 2197 } 2198 2199 switch (ActiveScheme) { 2200 case PathDiagnosticConsumer::Extensive: 2201 GenerateExtensivePathDiagnostic(PD, PDB, N, visitors); 2202 break; 2203 case PathDiagnosticConsumer::Minimal: 2204 GenerateMinimalPathDiagnostic(PD, PDB, N, visitors); 2205 break; 2206 case PathDiagnosticConsumer::None: 2207 GenerateVisitorsOnlyPathDiagnostic(PD, PDB, N, visitors); 2208 break; 2209 } 2210 2211 // Clean up the visitors we used. 2212 llvm::DeleteContainerPointers(visitors); 2213 2214 // Did anything change while generating this path? 2215 finalReportConfigToken = R->getConfigurationChangeToken(); 2216 } while (finalReportConfigToken != origReportConfigToken); 2217 2218 if (!R->isValid()) 2219 continue; 2220 2221 // Finally, prune the diagnostic path of uninteresting stuff. 2222 if (!PD.path.empty()) { 2223 // Remove messages that are basically the same. 2224 removeRedundantMsgs(PD.getMutablePieces()); 2225 2226 if (R->shouldPrunePath() && 2227 getEngine().getAnalysisManager().options.shouldPrunePaths()) { 2228 bool stillHasNotes = RemoveUnneededCalls(PD.getMutablePieces(), R); 2229 assert(stillHasNotes); 2230 (void)stillHasNotes; 2231 } 2232 2233 adjustCallLocations(PD.getMutablePieces()); 2234 } 2235 2236 // We found a report and didn't suppress it. 2237 return true; 2238 } 2239 2240 // We suppressed all the reports in this equivalence class. 2241 return false; 2242 } 2243 2244 void BugReporter::Register(BugType *BT) { 2245 BugTypes = F.add(BugTypes, BT); 2246 } 2247 2248 void BugReporter::emitReport(BugReport* R) { 2249 // Compute the bug report's hash to determine its equivalence class. 2250 llvm::FoldingSetNodeID ID; 2251 R->Profile(ID); 2252 2253 // Lookup the equivance class. If there isn't one, create it. 2254 BugType& BT = R->getBugType(); 2255 Register(&BT); 2256 void *InsertPos; 2257 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos); 2258 2259 if (!EQ) { 2260 EQ = new BugReportEquivClass(R); 2261 EQClasses.InsertNode(EQ, InsertPos); 2262 EQClassesVector.push_back(EQ); 2263 } 2264 else 2265 EQ->AddReport(R); 2266 } 2267 2268 2269 //===----------------------------------------------------------------------===// 2270 // Emitting reports in equivalence classes. 2271 //===----------------------------------------------------------------------===// 2272 2273 namespace { 2274 struct FRIEC_WLItem { 2275 const ExplodedNode *N; 2276 ExplodedNode::const_succ_iterator I, E; 2277 2278 FRIEC_WLItem(const ExplodedNode *n) 2279 : N(n), I(N->succ_begin()), E(N->succ_end()) {} 2280 }; 2281 } 2282 2283 static BugReport * 2284 FindReportInEquivalenceClass(BugReportEquivClass& EQ, 2285 SmallVectorImpl<BugReport*> &bugReports) { 2286 2287 BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end(); 2288 assert(I != E); 2289 BugType& BT = I->getBugType(); 2290 2291 // If we don't need to suppress any of the nodes because they are 2292 // post-dominated by a sink, simply add all the nodes in the equivalence class 2293 // to 'Nodes'. Any of the reports will serve as a "representative" report. 2294 if (!BT.isSuppressOnSink()) { 2295 BugReport *R = I; 2296 for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) { 2297 const ExplodedNode *N = I->getErrorNode(); 2298 if (N) { 2299 R = I; 2300 bugReports.push_back(R); 2301 } 2302 } 2303 return R; 2304 } 2305 2306 // For bug reports that should be suppressed when all paths are post-dominated 2307 // by a sink node, iterate through the reports in the equivalence class 2308 // until we find one that isn't post-dominated (if one exists). We use a 2309 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write 2310 // this as a recursive function, but we don't want to risk blowing out the 2311 // stack for very long paths. 2312 BugReport *exampleReport = 0; 2313 2314 for (; I != E; ++I) { 2315 const ExplodedNode *errorNode = I->getErrorNode(); 2316 2317 if (!errorNode) 2318 continue; 2319 if (errorNode->isSink()) { 2320 llvm_unreachable( 2321 "BugType::isSuppressSink() should not be 'true' for sink end nodes"); 2322 } 2323 // No successors? By definition this nodes isn't post-dominated by a sink. 2324 if (errorNode->succ_empty()) { 2325 bugReports.push_back(I); 2326 if (!exampleReport) 2327 exampleReport = I; 2328 continue; 2329 } 2330 2331 // At this point we know that 'N' is not a sink and it has at least one 2332 // successor. Use a DFS worklist to find a non-sink end-of-path node. 2333 typedef FRIEC_WLItem WLItem; 2334 typedef SmallVector<WLItem, 10> DFSWorkList; 2335 llvm::DenseMap<const ExplodedNode *, unsigned> Visited; 2336 2337 DFSWorkList WL; 2338 WL.push_back(errorNode); 2339 Visited[errorNode] = 1; 2340 2341 while (!WL.empty()) { 2342 WLItem &WI = WL.back(); 2343 assert(!WI.N->succ_empty()); 2344 2345 for (; WI.I != WI.E; ++WI.I) { 2346 const ExplodedNode *Succ = *WI.I; 2347 // End-of-path node? 2348 if (Succ->succ_empty()) { 2349 // If we found an end-of-path node that is not a sink. 2350 if (!Succ->isSink()) { 2351 bugReports.push_back(I); 2352 if (!exampleReport) 2353 exampleReport = I; 2354 WL.clear(); 2355 break; 2356 } 2357 // Found a sink? Continue on to the next successor. 2358 continue; 2359 } 2360 // Mark the successor as visited. If it hasn't been explored, 2361 // enqueue it to the DFS worklist. 2362 unsigned &mark = Visited[Succ]; 2363 if (!mark) { 2364 mark = 1; 2365 WL.push_back(Succ); 2366 break; 2367 } 2368 } 2369 2370 // The worklist may have been cleared at this point. First 2371 // check if it is empty before checking the last item. 2372 if (!WL.empty() && &WL.back() == &WI) 2373 WL.pop_back(); 2374 } 2375 } 2376 2377 // ExampleReport will be NULL if all the nodes in the equivalence class 2378 // were post-dominated by sinks. 2379 return exampleReport; 2380 } 2381 2382 void BugReporter::FlushReport(BugReportEquivClass& EQ) { 2383 SmallVector<BugReport*, 10> bugReports; 2384 BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports); 2385 if (exampleReport) { 2386 const PathDiagnosticConsumers &C = getPathDiagnosticConsumers(); 2387 for (PathDiagnosticConsumers::const_iterator I=C.begin(), 2388 E=C.end(); I != E; ++I) { 2389 FlushReport(exampleReport, **I, bugReports); 2390 } 2391 } 2392 } 2393 2394 void BugReporter::FlushReport(BugReport *exampleReport, 2395 PathDiagnosticConsumer &PD, 2396 ArrayRef<BugReport*> bugReports) { 2397 2398 // FIXME: Make sure we use the 'R' for the path that was actually used. 2399 // Probably doesn't make a difference in practice. 2400 BugType& BT = exampleReport->getBugType(); 2401 2402 OwningPtr<PathDiagnostic> 2403 D(new PathDiagnostic(exampleReport->getDeclWithIssue(), 2404 exampleReport->getBugType().getName(), 2405 exampleReport->getDescription(), 2406 exampleReport->getShortDescription(/*Fallback=*/false), 2407 BT.getCategory(), 2408 exampleReport->getUniqueingLocation(), 2409 exampleReport->getUniqueingDecl())); 2410 2411 MaxBugClassSize = std::max(bugReports.size(), 2412 static_cast<size_t>(MaxBugClassSize)); 2413 2414 // Generate the full path diagnostic, using the generation scheme 2415 // specified by the PathDiagnosticConsumer. Note that we have to generate 2416 // path diagnostics even for consumers which do not support paths, because 2417 // the BugReporterVisitors may mark this bug as a false positive. 2418 if (!bugReports.empty()) 2419 if (!generatePathDiagnostic(*D.get(), PD, bugReports)) 2420 return; 2421 2422 MaxValidBugClassSize = std::max(bugReports.size(), 2423 static_cast<size_t>(MaxValidBugClassSize)); 2424 2425 // If the path is empty, generate a single step path with the location 2426 // of the issue. 2427 if (D->path.empty()) { 2428 PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager()); 2429 PathDiagnosticPiece *piece = 2430 new PathDiagnosticEventPiece(L, exampleReport->getDescription()); 2431 BugReport::ranges_iterator Beg, End; 2432 llvm::tie(Beg, End) = exampleReport->getRanges(); 2433 for ( ; Beg != End; ++Beg) 2434 piece->addRange(*Beg); 2435 D->setEndOfPath(piece); 2436 } 2437 2438 // Get the meta data. 2439 const BugReport::ExtraTextList &Meta = exampleReport->getExtraText(); 2440 for (BugReport::ExtraTextList::const_iterator i = Meta.begin(), 2441 e = Meta.end(); i != e; ++i) { 2442 D->addMeta(*i); 2443 } 2444 2445 PD.HandlePathDiagnostic(D.take()); 2446 } 2447 2448 void BugReporter::EmitBasicReport(const Decl *DeclWithIssue, 2449 StringRef name, 2450 StringRef category, 2451 StringRef str, PathDiagnosticLocation Loc, 2452 SourceRange* RBeg, unsigned NumRanges) { 2453 2454 // 'BT' is owned by BugReporter. 2455 BugType *BT = getBugTypeForName(name, category); 2456 BugReport *R = new BugReport(*BT, str, Loc); 2457 R->setDeclWithIssue(DeclWithIssue); 2458 for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg); 2459 emitReport(R); 2460 } 2461 2462 BugType *BugReporter::getBugTypeForName(StringRef name, 2463 StringRef category) { 2464 SmallString<136> fullDesc; 2465 llvm::raw_svector_ostream(fullDesc) << name << ":" << category; 2466 llvm::StringMapEntry<BugType *> & 2467 entry = StrBugTypes.GetOrCreateValue(fullDesc); 2468 BugType *BT = entry.getValue(); 2469 if (!BT) { 2470 BT = new BugType(name, category); 2471 entry.setValue(BT); 2472 } 2473 return BT; 2474 } 2475