BugReporter.cpp revision c70fac3c52092013b08163187f034b73c94bf3d0
156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// BugReporter.cpp - Generate PathDiagnostics for Bugs ------------*- C++ -*--// 256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// 356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// The LLVM Compiler Infrastructure 456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// 556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// This file is distributed under the University of Illinois Open Source 656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// License. See LICENSE.TXT for details. 756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// 856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson//===----------------------------------------------------------------------===// 956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// 1056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// This file defines BugReporter, a utility class for generating 1156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// PathDiagnostics. 1256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson// 1356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson//===----------------------------------------------------------------------===// 1456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 1556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#define DEBUG_TYPE "BugReporter" 1656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson 1756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h" 1856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/AST/ASTContext.h" 1956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/AST/DeclObjC.h" 2056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/AST/Expr.h" 2156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/AST/ParentMap.h" 2256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/AST/StmtObjC.h" 2356ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/Analysis/CFG.h" 2456ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/Analysis/ProgramPoint.h" 2556ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/Basic/SourceManager.h" 2656ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 2756ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 2856ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 2956ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "llvm/ADT/DenseMap.h" 3056ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "llvm/ADT/IntrusiveRefCntPtr.h" 3156ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#include "llvm/ADT/OwningPtr.h" 3256ed4167b942ec265f9cee70ac4d71d10b3835ceBen Dodson#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 38using namespace clang; 39using namespace ento; 40 41STATISTIC(MaxBugClassSize, 42 "The maximum number of bug reports in the same equivalence class"); 43STATISTIC(MaxValidBugClassSize, 44 "The maximum number of bug reports in the same equivalence class " 45 "where at least one report is valid (not suppressed)"); 46 47BugReporterVisitor::~BugReporterVisitor() {} 48 49void BugReporterContext::anchor() {} 50 51//===----------------------------------------------------------------------===// 52// Helper routines for walking the ExplodedGraph and fetching statements. 53//===----------------------------------------------------------------------===// 54 55static const Stmt *GetPreviousStmt(const ExplodedNode *N) { 56 for (N = N->getFirstPred(); N; N = N->getFirstPred()) 57 if (const Stmt *S = PathDiagnosticLocation::getStmt(N)) 58 return S; 59 60 return 0; 61} 62 63static inline const Stmt* 64GetCurrentOrPreviousStmt(const ExplodedNode *N) { 65 if (const Stmt *S = PathDiagnosticLocation::getStmt(N)) 66 return S; 67 68 return GetPreviousStmt(N); 69} 70 71//===----------------------------------------------------------------------===// 72// Diagnostic cleanup. 73//===----------------------------------------------------------------------===// 74 75static PathDiagnosticEventPiece * 76eventsDescribeSameCondition(PathDiagnosticEventPiece *X, 77 PathDiagnosticEventPiece *Y) { 78 // Prefer diagnostics that come from ConditionBRVisitor over 79 // those that came from TrackConstraintBRVisitor. 80 const void *tagPreferred = ConditionBRVisitor::getTag(); 81 const void *tagLesser = TrackConstraintBRVisitor::getTag(); 82 83 if (X->getLocation() != Y->getLocation()) 84 return 0; 85 86 if (X->getTag() == tagPreferred && Y->getTag() == tagLesser) 87 return X; 88 89 if (Y->getTag() == tagPreferred && X->getTag() == tagLesser) 90 return Y; 91 92 return 0; 93} 94 95/// An optimization pass over PathPieces that removes redundant diagnostics 96/// generated by both ConditionBRVisitor and TrackConstraintBRVisitor. Both 97/// BugReporterVisitors use different methods to generate diagnostics, with 98/// one capable of emitting diagnostics in some cases but not in others. This 99/// can lead to redundant diagnostic pieces at the same point in a path. 100static void removeRedundantMsgs(PathPieces &path) { 101 unsigned N = path.size(); 102 if (N < 2) 103 return; 104 // NOTE: this loop intentionally is not using an iterator. Instead, we 105 // are streaming the path and modifying it in place. This is done by 106 // grabbing the front, processing it, and if we decide to keep it append 107 // it to the end of the path. The entire path is processed in this way. 108 for (unsigned i = 0; i < N; ++i) { 109 IntrusiveRefCntPtr<PathDiagnosticPiece> piece(path.front()); 110 path.pop_front(); 111 112 switch (piece->getKind()) { 113 case clang::ento::PathDiagnosticPiece::Call: 114 removeRedundantMsgs(cast<PathDiagnosticCallPiece>(piece)->path); 115 break; 116 case clang::ento::PathDiagnosticPiece::Macro: 117 removeRedundantMsgs(cast<PathDiagnosticMacroPiece>(piece)->subPieces); 118 break; 119 case clang::ento::PathDiagnosticPiece::ControlFlow: 120 break; 121 case clang::ento::PathDiagnosticPiece::Event: { 122 if (i == N-1) 123 break; 124 125 if (PathDiagnosticEventPiece *nextEvent = 126 dyn_cast<PathDiagnosticEventPiece>(path.front().getPtr())) { 127 PathDiagnosticEventPiece *event = 128 cast<PathDiagnosticEventPiece>(piece); 129 // Check to see if we should keep one of the two pieces. If we 130 // come up with a preference, record which piece to keep, and consume 131 // another piece from the path. 132 if (PathDiagnosticEventPiece *pieceToKeep = 133 eventsDescribeSameCondition(event, nextEvent)) { 134 piece = pieceToKeep; 135 path.pop_front(); 136 ++i; 137 } 138 } 139 break; 140 } 141 } 142 path.push_back(piece); 143 } 144} 145 146/// A map from PathDiagnosticPiece to the LocationContext of the inlined 147/// function call it represents. 148typedef llvm::DenseMap<const PathDiagnosticCallPiece*, const LocationContext*> 149 LocationContextMap; 150 151/// Recursively scan through a path and prune out calls and macros pieces 152/// that aren't needed. Return true if afterwards the path contains 153/// "interesting stuff" which means it shouldn't be pruned from the parent path. 154static bool removeUnneededCalls(PathPieces &pieces, BugReport *R, 155 LocationContextMap &LCM) { 156 bool containsSomethingInteresting = false; 157 const unsigned N = pieces.size(); 158 159 for (unsigned i = 0 ; i < N ; ++i) { 160 // Remove the front piece from the path. If it is still something we 161 // want to keep once we are done, we will push it back on the end. 162 IntrusiveRefCntPtr<PathDiagnosticPiece> piece(pieces.front()); 163 pieces.pop_front(); 164 165 // Throw away pieces with invalid locations. Note that we can't throw away 166 // calls just yet because they might have something interesting inside them. 167 // If so, their locations will be adjusted as necessary later. 168 if (piece->getKind() != PathDiagnosticPiece::Call && 169 piece->getLocation().asLocation().isInvalid()) 170 continue; 171 172 switch (piece->getKind()) { 173 case PathDiagnosticPiece::Call: { 174 PathDiagnosticCallPiece *call = cast<PathDiagnosticCallPiece>(piece); 175 // Check if the location context is interesting. 176 assert(LCM.count(call)); 177 if (R->isInteresting(LCM[call])) { 178 containsSomethingInteresting = true; 179 break; 180 } 181 182 if (!removeUnneededCalls(call->path, R, LCM)) 183 continue; 184 185 containsSomethingInteresting = true; 186 break; 187 } 188 case PathDiagnosticPiece::Macro: { 189 PathDiagnosticMacroPiece *macro = cast<PathDiagnosticMacroPiece>(piece); 190 if (!removeUnneededCalls(macro->subPieces, R, LCM)) 191 continue; 192 containsSomethingInteresting = true; 193 break; 194 } 195 case PathDiagnosticPiece::Event: { 196 PathDiagnosticEventPiece *event = cast<PathDiagnosticEventPiece>(piece); 197 198 // We never throw away an event, but we do throw it away wholesale 199 // as part of a path if we throw the entire path away. 200 containsSomethingInteresting |= !event->isPrunable(); 201 break; 202 } 203 case PathDiagnosticPiece::ControlFlow: 204 break; 205 } 206 207 pieces.push_back(piece); 208 } 209 210 return containsSomethingInteresting; 211} 212 213/// Recursively scan through a path and make sure that all call pieces have 214/// valid locations. Note that all other pieces with invalid locations should 215/// have already been pruned out. 216static void adjustCallLocations(PathPieces &Pieces, 217 PathDiagnosticLocation *LastCallLocation = 0) { 218 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E; ++I) { 219 PathDiagnosticCallPiece *Call = dyn_cast<PathDiagnosticCallPiece>(*I); 220 221 if (!Call) { 222 assert((*I)->getLocation().asLocation().isValid()); 223 continue; 224 } 225 226 if (LastCallLocation) { 227 if (!Call->callEnter.asLocation().isValid() || 228 Call->getCaller()->isImplicit()) 229 Call->callEnter = *LastCallLocation; 230 if (!Call->callReturn.asLocation().isValid() || 231 Call->getCaller()->isImplicit()) 232 Call->callReturn = *LastCallLocation; 233 } 234 235 // Recursively clean out the subclass. Keep this call around if 236 // it contains any informative diagnostics. 237 PathDiagnosticLocation *ThisCallLocation; 238 if (Call->callEnterWithin.asLocation().isValid() && 239 !Call->getCallee()->isImplicit()) 240 ThisCallLocation = &Call->callEnterWithin; 241 else 242 ThisCallLocation = &Call->callEnter; 243 244 assert(ThisCallLocation && "Outermost call has an invalid location"); 245 adjustCallLocations(Call->path, ThisCallLocation); 246 } 247} 248 249//===----------------------------------------------------------------------===// 250// PathDiagnosticBuilder and its associated routines and helper objects. 251//===----------------------------------------------------------------------===// 252 253namespace { 254class NodeMapClosure : public BugReport::NodeResolver { 255 InterExplodedGraphMap &M; 256public: 257 NodeMapClosure(InterExplodedGraphMap &m) : M(m) {} 258 259 const ExplodedNode *getOriginalNode(const ExplodedNode *N) { 260 return M.lookup(N); 261 } 262}; 263 264class PathDiagnosticBuilder : public BugReporterContext { 265 BugReport *R; 266 PathDiagnosticConsumer *PDC; 267 NodeMapClosure NMC; 268public: 269 const LocationContext *LC; 270 271 PathDiagnosticBuilder(GRBugReporter &br, 272 BugReport *r, InterExplodedGraphMap &Backmap, 273 PathDiagnosticConsumer *pdc) 274 : BugReporterContext(br), 275 R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext()) 276 {} 277 278 PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N); 279 280 PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os, 281 const ExplodedNode *N); 282 283 BugReport *getBugReport() { return R; } 284 285 Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); } 286 287 ParentMap& getParentMap() { return LC->getParentMap(); } 288 289 const Stmt *getParent(const Stmt *S) { 290 return getParentMap().getParent(S); 291 } 292 293 virtual NodeMapClosure& getNodeResolver() { return NMC; } 294 295 PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S); 296 297 PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const { 298 return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive; 299 } 300 301 bool supportsLogicalOpControlFlow() const { 302 return PDC ? PDC->supportsLogicalOpControlFlow() : true; 303 } 304}; 305} // end anonymous namespace 306 307PathDiagnosticLocation 308PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) { 309 if (const Stmt *S = PathDiagnosticLocation::getNextStmt(N)) 310 return PathDiagnosticLocation(S, getSourceManager(), LC); 311 312 return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(), 313 getSourceManager()); 314} 315 316PathDiagnosticLocation 317PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os, 318 const ExplodedNode *N) { 319 320 // Slow, but probably doesn't matter. 321 if (os.str().empty()) 322 os << ' '; 323 324 const PathDiagnosticLocation &Loc = ExecutionContinues(N); 325 326 if (Loc.asStmt()) 327 os << "Execution continues on line " 328 << getSourceManager().getExpansionLineNumber(Loc.asLocation()) 329 << '.'; 330 else { 331 os << "Execution jumps to the end of the "; 332 const Decl *D = N->getLocationContext()->getDecl(); 333 if (isa<ObjCMethodDecl>(D)) 334 os << "method"; 335 else if (isa<FunctionDecl>(D)) 336 os << "function"; 337 else { 338 assert(isa<BlockDecl>(D)); 339 os << "anonymous block"; 340 } 341 os << '.'; 342 } 343 344 return Loc; 345} 346 347static bool IsNested(const Stmt *S, ParentMap &PM) { 348 if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S))) 349 return true; 350 351 const Stmt *Parent = PM.getParentIgnoreParens(S); 352 353 if (Parent) 354 switch (Parent->getStmtClass()) { 355 case Stmt::ForStmtClass: 356 case Stmt::DoStmtClass: 357 case Stmt::WhileStmtClass: 358 return true; 359 default: 360 break; 361 } 362 363 return false; 364} 365 366PathDiagnosticLocation 367PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) { 368 assert(S && "Null Stmt *passed to getEnclosingStmtLocation"); 369 ParentMap &P = getParentMap(); 370 SourceManager &SMgr = getSourceManager(); 371 372 while (IsNested(S, P)) { 373 const Stmt *Parent = P.getParentIgnoreParens(S); 374 375 if (!Parent) 376 break; 377 378 switch (Parent->getStmtClass()) { 379 case Stmt::BinaryOperatorClass: { 380 const BinaryOperator *B = cast<BinaryOperator>(Parent); 381 if (B->isLogicalOp()) 382 return PathDiagnosticLocation(S, SMgr, LC); 383 break; 384 } 385 case Stmt::CompoundStmtClass: 386 case Stmt::StmtExprClass: 387 return PathDiagnosticLocation(S, SMgr, LC); 388 case Stmt::ChooseExprClass: 389 // Similar to '?' if we are referring to condition, just have the edge 390 // point to the entire choose expression. 391 if (cast<ChooseExpr>(Parent)->getCond() == S) 392 return PathDiagnosticLocation(Parent, SMgr, LC); 393 else 394 return PathDiagnosticLocation(S, SMgr, LC); 395 case Stmt::BinaryConditionalOperatorClass: 396 case Stmt::ConditionalOperatorClass: 397 // For '?', if we are referring to condition, just have the edge point 398 // to the entire '?' expression. 399 if (cast<AbstractConditionalOperator>(Parent)->getCond() == S) 400 return PathDiagnosticLocation(Parent, SMgr, LC); 401 else 402 return PathDiagnosticLocation(S, SMgr, LC); 403 case Stmt::DoStmtClass: 404 return PathDiagnosticLocation(S, SMgr, LC); 405 case Stmt::ForStmtClass: 406 if (cast<ForStmt>(Parent)->getBody() == S) 407 return PathDiagnosticLocation(S, SMgr, LC); 408 break; 409 case Stmt::IfStmtClass: 410 if (cast<IfStmt>(Parent)->getCond() != S) 411 return PathDiagnosticLocation(S, SMgr, LC); 412 break; 413 case Stmt::ObjCForCollectionStmtClass: 414 if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S) 415 return PathDiagnosticLocation(S, SMgr, LC); 416 break; 417 case Stmt::WhileStmtClass: 418 if (cast<WhileStmt>(Parent)->getCond() != S) 419 return PathDiagnosticLocation(S, SMgr, LC); 420 break; 421 default: 422 break; 423 } 424 425 S = Parent; 426 } 427 428 assert(S && "Cannot have null Stmt for PathDiagnosticLocation"); 429 430 // Special case: DeclStmts can appear in for statement declarations, in which 431 // case the ForStmt is the context. 432 if (isa<DeclStmt>(S)) { 433 if (const Stmt *Parent = P.getParent(S)) { 434 switch (Parent->getStmtClass()) { 435 case Stmt::ForStmtClass: 436 case Stmt::ObjCForCollectionStmtClass: 437 return PathDiagnosticLocation(Parent, SMgr, LC); 438 default: 439 break; 440 } 441 } 442 } 443 else if (isa<BinaryOperator>(S)) { 444 // Special case: the binary operator represents the initialization 445 // code in a for statement (this can happen when the variable being 446 // initialized is an old variable. 447 if (const ForStmt *FS = 448 dyn_cast_or_null<ForStmt>(P.getParentIgnoreParens(S))) { 449 if (FS->getInit() == S) 450 return PathDiagnosticLocation(FS, SMgr, LC); 451 } 452 } 453 454 return PathDiagnosticLocation(S, SMgr, LC); 455} 456 457//===----------------------------------------------------------------------===// 458// "Visitors only" path diagnostic generation algorithm. 459//===----------------------------------------------------------------------===// 460static bool GenerateVisitorsOnlyPathDiagnostic(PathDiagnostic &PD, 461 PathDiagnosticBuilder &PDB, 462 const ExplodedNode *N, 463 ArrayRef<BugReporterVisitor *> visitors) { 464 // All path generation skips the very first node (the error node). 465 // This is because there is special handling for the end-of-path note. 466 N = N->getFirstPred(); 467 if (!N) 468 return true; 469 470 BugReport *R = PDB.getBugReport(); 471 while (const ExplodedNode *Pred = N->getFirstPred()) { 472 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 473 E = visitors.end(); 474 I != E; ++I) { 475 // Visit all the node pairs, but throw the path pieces away. 476 PathDiagnosticPiece *Piece = (*I)->VisitNode(N, Pred, PDB, *R); 477 delete Piece; 478 } 479 480 N = Pred; 481 } 482 483 return R->isValid(); 484} 485 486//===----------------------------------------------------------------------===// 487// "Minimal" path diagnostic generation algorithm. 488//===----------------------------------------------------------------------===// 489typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair; 490typedef SmallVector<StackDiagPair, 6> StackDiagVector; 491 492static void updateStackPiecesWithMessage(PathDiagnosticPiece *P, 493 StackDiagVector &CallStack) { 494 // If the piece contains a special message, add it to all the call 495 // pieces on the active stack. 496 if (PathDiagnosticEventPiece *ep = 497 dyn_cast<PathDiagnosticEventPiece>(P)) { 498 499 if (ep->hasCallStackHint()) 500 for (StackDiagVector::iterator I = CallStack.begin(), 501 E = CallStack.end(); I != E; ++I) { 502 PathDiagnosticCallPiece *CP = I->first; 503 const ExplodedNode *N = I->second; 504 std::string stackMsg = ep->getCallStackMessage(N); 505 506 // The last message on the path to final bug is the most important 507 // one. Since we traverse the path backwards, do not add the message 508 // if one has been previously added. 509 if (!CP->hasCallStackMessage()) 510 CP->setCallStackMessage(stackMsg); 511 } 512 } 513} 514 515static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM); 516 517static bool GenerateMinimalPathDiagnostic(PathDiagnostic& PD, 518 PathDiagnosticBuilder &PDB, 519 const ExplodedNode *N, 520 LocationContextMap &LCM, 521 ArrayRef<BugReporterVisitor *> visitors) { 522 523 SourceManager& SMgr = PDB.getSourceManager(); 524 const LocationContext *LC = PDB.LC; 525 const ExplodedNode *NextNode = N->pred_empty() 526 ? NULL : *(N->pred_begin()); 527 528 StackDiagVector CallStack; 529 530 while (NextNode) { 531 N = NextNode; 532 PDB.LC = N->getLocationContext(); 533 NextNode = N->getFirstPred(); 534 535 ProgramPoint P = N->getLocation(); 536 537 do { 538 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 539 PathDiagnosticCallPiece *C = 540 PathDiagnosticCallPiece::construct(N, *CE, SMgr); 541 // Record the mapping from call piece to LocationContext. 542 LCM[C] = CE->getCalleeContext(); 543 PD.getActivePath().push_front(C); 544 PD.pushActivePath(&C->path); 545 CallStack.push_back(StackDiagPair(C, N)); 546 break; 547 } 548 549 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 550 // Flush all locations, and pop the active path. 551 bool VisitedEntireCall = PD.isWithinCall(); 552 PD.popActivePath(); 553 554 // Either we just added a bunch of stuff to the top-level path, or 555 // we have a previous CallExitEnd. If the former, it means that the 556 // path terminated within a function call. We must then take the 557 // current contents of the active path and place it within 558 // a new PathDiagnosticCallPiece. 559 PathDiagnosticCallPiece *C; 560 if (VisitedEntireCall) { 561 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 562 } else { 563 const Decl *Caller = CE->getLocationContext()->getDecl(); 564 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 565 // Record the mapping from call piece to LocationContext. 566 LCM[C] = CE->getCalleeContext(); 567 } 568 569 C->setCallee(*CE, SMgr); 570 if (!CallStack.empty()) { 571 assert(CallStack.back().first == C); 572 CallStack.pop_back(); 573 } 574 break; 575 } 576 577 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 578 const CFGBlock *Src = BE->getSrc(); 579 const CFGBlock *Dst = BE->getDst(); 580 const Stmt *T = Src->getTerminator(); 581 582 if (!T) 583 break; 584 585 PathDiagnosticLocation Start = 586 PathDiagnosticLocation::createBegin(T, SMgr, 587 N->getLocationContext()); 588 589 switch (T->getStmtClass()) { 590 default: 591 break; 592 593 case Stmt::GotoStmtClass: 594 case Stmt::IndirectGotoStmtClass: { 595 const Stmt *S = PathDiagnosticLocation::getNextStmt(N); 596 597 if (!S) 598 break; 599 600 std::string sbuf; 601 llvm::raw_string_ostream os(sbuf); 602 const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S); 603 604 os << "Control jumps to line " 605 << End.asLocation().getExpansionLineNumber(); 606 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 607 Start, End, os.str())); 608 break; 609 } 610 611 case Stmt::SwitchStmtClass: { 612 // Figure out what case arm we took. 613 std::string sbuf; 614 llvm::raw_string_ostream os(sbuf); 615 616 if (const Stmt *S = Dst->getLabel()) { 617 PathDiagnosticLocation End(S, SMgr, LC); 618 619 switch (S->getStmtClass()) { 620 default: 621 os << "No cases match in the switch statement. " 622 "Control jumps to line " 623 << End.asLocation().getExpansionLineNumber(); 624 break; 625 case Stmt::DefaultStmtClass: 626 os << "Control jumps to the 'default' case at line " 627 << End.asLocation().getExpansionLineNumber(); 628 break; 629 630 case Stmt::CaseStmtClass: { 631 os << "Control jumps to 'case "; 632 const CaseStmt *Case = cast<CaseStmt>(S); 633 const Expr *LHS = Case->getLHS()->IgnoreParenCasts(); 634 635 // Determine if it is an enum. 636 bool GetRawInt = true; 637 638 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) { 639 // FIXME: Maybe this should be an assertion. Are there cases 640 // were it is not an EnumConstantDecl? 641 const EnumConstantDecl *D = 642 dyn_cast<EnumConstantDecl>(DR->getDecl()); 643 644 if (D) { 645 GetRawInt = false; 646 os << *D; 647 } 648 } 649 650 if (GetRawInt) 651 os << LHS->EvaluateKnownConstInt(PDB.getASTContext()); 652 653 os << ":' at line " 654 << End.asLocation().getExpansionLineNumber(); 655 break; 656 } 657 } 658 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 659 Start, End, os.str())); 660 } 661 else { 662 os << "'Default' branch taken. "; 663 const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N); 664 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 665 Start, End, os.str())); 666 } 667 668 break; 669 } 670 671 case Stmt::BreakStmtClass: 672 case Stmt::ContinueStmtClass: { 673 std::string sbuf; 674 llvm::raw_string_ostream os(sbuf); 675 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 676 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 677 Start, End, os.str())); 678 break; 679 } 680 681 // Determine control-flow for ternary '?'. 682 case Stmt::BinaryConditionalOperatorClass: 683 case Stmt::ConditionalOperatorClass: { 684 std::string sbuf; 685 llvm::raw_string_ostream os(sbuf); 686 os << "'?' condition is "; 687 688 if (*(Src->succ_begin()+1) == Dst) 689 os << "false"; 690 else 691 os << "true"; 692 693 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 694 695 if (const Stmt *S = End.asStmt()) 696 End = PDB.getEnclosingStmtLocation(S); 697 698 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 699 Start, End, os.str())); 700 break; 701 } 702 703 // Determine control-flow for short-circuited '&&' and '||'. 704 case Stmt::BinaryOperatorClass: { 705 if (!PDB.supportsLogicalOpControlFlow()) 706 break; 707 708 const BinaryOperator *B = cast<BinaryOperator>(T); 709 std::string sbuf; 710 llvm::raw_string_ostream os(sbuf); 711 os << "Left side of '"; 712 713 if (B->getOpcode() == BO_LAnd) { 714 os << "&&" << "' is "; 715 716 if (*(Src->succ_begin()+1) == Dst) { 717 os << "false"; 718 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 719 PathDiagnosticLocation Start = 720 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 721 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 722 Start, End, os.str())); 723 } 724 else { 725 os << "true"; 726 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 727 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 728 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 729 Start, End, os.str())); 730 } 731 } 732 else { 733 assert(B->getOpcode() == BO_LOr); 734 os << "||" << "' is "; 735 736 if (*(Src->succ_begin()+1) == Dst) { 737 os << "false"; 738 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 739 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 740 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 741 Start, End, os.str())); 742 } 743 else { 744 os << "true"; 745 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 746 PathDiagnosticLocation Start = 747 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 748 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 749 Start, End, os.str())); 750 } 751 } 752 753 break; 754 } 755 756 case Stmt::DoStmtClass: { 757 if (*(Src->succ_begin()) == Dst) { 758 std::string sbuf; 759 llvm::raw_string_ostream os(sbuf); 760 761 os << "Loop condition is true. "; 762 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 763 764 if (const Stmt *S = End.asStmt()) 765 End = PDB.getEnclosingStmtLocation(S); 766 767 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 768 Start, End, os.str())); 769 } 770 else { 771 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 772 773 if (const Stmt *S = End.asStmt()) 774 End = PDB.getEnclosingStmtLocation(S); 775 776 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 777 Start, End, "Loop condition is false. Exiting loop")); 778 } 779 780 break; 781 } 782 783 case Stmt::WhileStmtClass: 784 case Stmt::ForStmtClass: { 785 if (*(Src->succ_begin()+1) == Dst) { 786 std::string sbuf; 787 llvm::raw_string_ostream os(sbuf); 788 789 os << "Loop condition is false. "; 790 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 791 if (const Stmt *S = End.asStmt()) 792 End = PDB.getEnclosingStmtLocation(S); 793 794 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 795 Start, End, os.str())); 796 } 797 else { 798 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 799 if (const Stmt *S = End.asStmt()) 800 End = PDB.getEnclosingStmtLocation(S); 801 802 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 803 Start, End, "Loop condition is true. Entering loop body")); 804 } 805 806 break; 807 } 808 809 case Stmt::IfStmtClass: { 810 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 811 812 if (const Stmt *S = End.asStmt()) 813 End = PDB.getEnclosingStmtLocation(S); 814 815 if (*(Src->succ_begin()+1) == Dst) 816 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 817 Start, End, "Taking false branch")); 818 else 819 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 820 Start, End, "Taking true branch")); 821 822 break; 823 } 824 } 825 } 826 } while(0); 827 828 if (NextNode) { 829 // Add diagnostic pieces from custom visitors. 830 BugReport *R = PDB.getBugReport(); 831 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 832 E = visitors.end(); 833 I != E; ++I) { 834 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) { 835 PD.getActivePath().push_front(p); 836 updateStackPiecesWithMessage(p, CallStack); 837 } 838 } 839 } 840 } 841 842 if (!PDB.getBugReport()->isValid()) 843 return false; 844 845 // After constructing the full PathDiagnostic, do a pass over it to compact 846 // PathDiagnosticPieces that occur within a macro. 847 CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager()); 848 return true; 849} 850 851//===----------------------------------------------------------------------===// 852// "Extensive" PathDiagnostic generation. 853//===----------------------------------------------------------------------===// 854 855static bool IsControlFlowExpr(const Stmt *S) { 856 const Expr *E = dyn_cast<Expr>(S); 857 858 if (!E) 859 return false; 860 861 E = E->IgnoreParenCasts(); 862 863 if (isa<AbstractConditionalOperator>(E)) 864 return true; 865 866 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E)) 867 if (B->isLogicalOp()) 868 return true; 869 870 return false; 871} 872 873namespace { 874class ContextLocation : public PathDiagnosticLocation { 875 bool IsDead; 876public: 877 ContextLocation(const PathDiagnosticLocation &L, bool isdead = false) 878 : PathDiagnosticLocation(L), IsDead(isdead) {} 879 880 void markDead() { IsDead = true; } 881 bool isDead() const { return IsDead; } 882}; 883 884class EdgeBuilder { 885 std::vector<ContextLocation> CLocs; 886 typedef std::vector<ContextLocation>::iterator iterator; 887 PathDiagnostic &PD; 888 PathDiagnosticBuilder &PDB; 889 PathDiagnosticLocation PrevLoc; 890 891 bool IsConsumedExpr(const PathDiagnosticLocation &L); 892 893 bool containsLocation(const PathDiagnosticLocation &Container, 894 const PathDiagnosticLocation &Containee); 895 896 PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L); 897 898 PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L, 899 bool firstCharOnly = false) { 900 if (const Stmt *S = L.asStmt()) { 901 const Stmt *Original = S; 902 while (1) { 903 // Adjust the location for some expressions that are best referenced 904 // by one of their subexpressions. 905 switch (S->getStmtClass()) { 906 default: 907 break; 908 case Stmt::ParenExprClass: 909 case Stmt::GenericSelectionExprClass: 910 S = cast<Expr>(S)->IgnoreParens(); 911 firstCharOnly = true; 912 continue; 913 case Stmt::BinaryConditionalOperatorClass: 914 case Stmt::ConditionalOperatorClass: 915 S = cast<AbstractConditionalOperator>(S)->getCond(); 916 firstCharOnly = true; 917 continue; 918 case Stmt::ChooseExprClass: 919 S = cast<ChooseExpr>(S)->getCond(); 920 firstCharOnly = true; 921 continue; 922 case Stmt::BinaryOperatorClass: 923 S = cast<BinaryOperator>(S)->getLHS(); 924 firstCharOnly = true; 925 continue; 926 } 927 928 break; 929 } 930 931 if (S != Original) 932 L = PathDiagnosticLocation(S, L.getManager(), PDB.LC); 933 } 934 935 if (firstCharOnly) 936 L = PathDiagnosticLocation::createSingleLocation(L); 937 938 return L; 939 } 940 941 void popLocation() { 942 if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) { 943 // For contexts, we only one the first character as the range. 944 rawAddEdge(cleanUpLocation(CLocs.back(), true)); 945 } 946 CLocs.pop_back(); 947 } 948 949public: 950 EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb) 951 : PD(pd), PDB(pdb) { 952 953 // If the PathDiagnostic already has pieces, add the enclosing statement 954 // of the first piece as a context as well. 955 if (!PD.path.empty()) { 956 PrevLoc = (*PD.path.begin())->getLocation(); 957 958 if (const Stmt *S = PrevLoc.asStmt()) 959 addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 960 } 961 } 962 963 ~EdgeBuilder() { 964 while (!CLocs.empty()) popLocation(); 965 966 // Finally, add an initial edge from the start location of the first 967 // statement (if it doesn't already exist). 968 PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin( 969 PDB.LC, 970 PDB.getSourceManager()); 971 if (L.isValid()) 972 rawAddEdge(L); 973 } 974 975 void flushLocations() { 976 while (!CLocs.empty()) 977 popLocation(); 978 PrevLoc = PathDiagnosticLocation(); 979 } 980 981 void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false, 982 bool IsPostJump = false); 983 984 void rawAddEdge(PathDiagnosticLocation NewLoc); 985 986 void addContext(const Stmt *S); 987 void addContext(const PathDiagnosticLocation &L); 988 void addExtendedContext(const Stmt *S); 989}; 990} // end anonymous namespace 991 992 993PathDiagnosticLocation 994EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) { 995 if (const Stmt *S = L.asStmt()) { 996 if (IsControlFlowExpr(S)) 997 return L; 998 999 return PDB.getEnclosingStmtLocation(S); 1000 } 1001 1002 return L; 1003} 1004 1005bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container, 1006 const PathDiagnosticLocation &Containee) { 1007 1008 if (Container == Containee) 1009 return true; 1010 1011 if (Container.asDecl()) 1012 return true; 1013 1014 if (const Stmt *S = Containee.asStmt()) 1015 if (const Stmt *ContainerS = Container.asStmt()) { 1016 while (S) { 1017 if (S == ContainerS) 1018 return true; 1019 S = PDB.getParent(S); 1020 } 1021 return false; 1022 } 1023 1024 // Less accurate: compare using source ranges. 1025 SourceRange ContainerR = Container.asRange(); 1026 SourceRange ContaineeR = Containee.asRange(); 1027 1028 SourceManager &SM = PDB.getSourceManager(); 1029 SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin()); 1030 SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd()); 1031 SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin()); 1032 SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd()); 1033 1034 unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg); 1035 unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd); 1036 unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg); 1037 unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd); 1038 1039 assert(ContainerBegLine <= ContainerEndLine); 1040 assert(ContaineeBegLine <= ContaineeEndLine); 1041 1042 return (ContainerBegLine <= ContaineeBegLine && 1043 ContainerEndLine >= ContaineeEndLine && 1044 (ContainerBegLine != ContaineeBegLine || 1045 SM.getExpansionColumnNumber(ContainerRBeg) <= 1046 SM.getExpansionColumnNumber(ContaineeRBeg)) && 1047 (ContainerEndLine != ContaineeEndLine || 1048 SM.getExpansionColumnNumber(ContainerREnd) >= 1049 SM.getExpansionColumnNumber(ContaineeREnd))); 1050} 1051 1052void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) { 1053 if (!PrevLoc.isValid()) { 1054 PrevLoc = NewLoc; 1055 return; 1056 } 1057 1058 const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc); 1059 const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc); 1060 1061 if (PrevLocClean.asLocation().isInvalid()) { 1062 PrevLoc = NewLoc; 1063 return; 1064 } 1065 1066 if (NewLocClean.asLocation() == PrevLocClean.asLocation()) 1067 return; 1068 1069 // FIXME: Ignore intra-macro edges for now. 1070 if (NewLocClean.asLocation().getExpansionLoc() == 1071 PrevLocClean.asLocation().getExpansionLoc()) 1072 return; 1073 1074 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean)); 1075 PrevLoc = NewLoc; 1076} 1077 1078void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd, 1079 bool IsPostJump) { 1080 1081 if (!alwaysAdd && NewLoc.asLocation().isMacroID()) 1082 return; 1083 1084 const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc); 1085 1086 while (!CLocs.empty()) { 1087 ContextLocation &TopContextLoc = CLocs.back(); 1088 1089 // Is the top location context the same as the one for the new location? 1090 if (TopContextLoc == CLoc) { 1091 if (alwaysAdd) { 1092 if (IsConsumedExpr(TopContextLoc)) 1093 TopContextLoc.markDead(); 1094 1095 rawAddEdge(NewLoc); 1096 } 1097 1098 if (IsPostJump) 1099 TopContextLoc.markDead(); 1100 return; 1101 } 1102 1103 if (containsLocation(TopContextLoc, CLoc)) { 1104 if (alwaysAdd) { 1105 rawAddEdge(NewLoc); 1106 1107 if (IsConsumedExpr(CLoc)) { 1108 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/true)); 1109 return; 1110 } 1111 } 1112 1113 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/IsPostJump)); 1114 return; 1115 } 1116 1117 // Context does not contain the location. Flush it. 1118 popLocation(); 1119 } 1120 1121 // If we reach here, there is no enclosing context. Just add the edge. 1122 rawAddEdge(NewLoc); 1123} 1124 1125bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) { 1126 if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt())) 1127 return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X); 1128 1129 return false; 1130} 1131 1132void EdgeBuilder::addExtendedContext(const Stmt *S) { 1133 if (!S) 1134 return; 1135 1136 const Stmt *Parent = PDB.getParent(S); 1137 while (Parent) { 1138 if (isa<CompoundStmt>(Parent)) 1139 Parent = PDB.getParent(Parent); 1140 else 1141 break; 1142 } 1143 1144 if (Parent) { 1145 switch (Parent->getStmtClass()) { 1146 case Stmt::DoStmtClass: 1147 case Stmt::ObjCAtSynchronizedStmtClass: 1148 addContext(Parent); 1149 default: 1150 break; 1151 } 1152 } 1153 1154 addContext(S); 1155} 1156 1157void EdgeBuilder::addContext(const Stmt *S) { 1158 if (!S) 1159 return; 1160 1161 PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC); 1162 addContext(L); 1163} 1164 1165void EdgeBuilder::addContext(const PathDiagnosticLocation &L) { 1166 while (!CLocs.empty()) { 1167 const PathDiagnosticLocation &TopContextLoc = CLocs.back(); 1168 1169 // Is the top location context the same as the one for the new location? 1170 if (TopContextLoc == L) 1171 return; 1172 1173 if (containsLocation(TopContextLoc, L)) { 1174 CLocs.push_back(L); 1175 return; 1176 } 1177 1178 // Context does not contain the location. Flush it. 1179 popLocation(); 1180 } 1181 1182 CLocs.push_back(L); 1183} 1184 1185// Cone-of-influence: support the reverse propagation of "interesting" symbols 1186// and values by tracing interesting calculations backwards through evaluated 1187// expressions along a path. This is probably overly complicated, but the idea 1188// is that if an expression computed an "interesting" value, the child 1189// expressions are are also likely to be "interesting" as well (which then 1190// propagates to the values they in turn compute). This reverse propagation 1191// is needed to track interesting correlations across function call boundaries, 1192// where formal arguments bind to actual arguments, etc. This is also needed 1193// because the constraint solver sometimes simplifies certain symbolic values 1194// into constants when appropriate, and this complicates reasoning about 1195// interesting values. 1196typedef llvm::DenseSet<const Expr *> InterestingExprs; 1197 1198static void reversePropagateIntererstingSymbols(BugReport &R, 1199 InterestingExprs &IE, 1200 const ProgramState *State, 1201 const Expr *Ex, 1202 const LocationContext *LCtx) { 1203 SVal V = State->getSVal(Ex, LCtx); 1204 if (!(R.isInteresting(V) || IE.count(Ex))) 1205 return; 1206 1207 switch (Ex->getStmtClass()) { 1208 default: 1209 if (!isa<CastExpr>(Ex)) 1210 break; 1211 // Fall through. 1212 case Stmt::BinaryOperatorClass: 1213 case Stmt::UnaryOperatorClass: { 1214 for (Stmt::const_child_iterator CI = Ex->child_begin(), 1215 CE = Ex->child_end(); 1216 CI != CE; ++CI) { 1217 if (const Expr *child = dyn_cast_or_null<Expr>(*CI)) { 1218 IE.insert(child); 1219 SVal ChildV = State->getSVal(child, LCtx); 1220 R.markInteresting(ChildV); 1221 } 1222 break; 1223 } 1224 } 1225 } 1226 1227 R.markInteresting(V); 1228} 1229 1230static void reversePropagateInterestingSymbols(BugReport &R, 1231 InterestingExprs &IE, 1232 const ProgramState *State, 1233 const LocationContext *CalleeCtx, 1234 const LocationContext *CallerCtx) 1235{ 1236 // FIXME: Handle non-CallExpr-based CallEvents. 1237 const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame(); 1238 const Stmt *CallSite = Callee->getCallSite(); 1239 if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) { 1240 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) { 1241 FunctionDecl::param_const_iterator PI = FD->param_begin(), 1242 PE = FD->param_end(); 1243 CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end(); 1244 for (; AI != AE && PI != PE; ++AI, ++PI) { 1245 if (const Expr *ArgE = *AI) { 1246 if (const ParmVarDecl *PD = *PI) { 1247 Loc LV = State->getLValue(PD, CalleeCtx); 1248 if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV))) 1249 IE.insert(ArgE); 1250 } 1251 } 1252 } 1253 } 1254 } 1255} 1256 1257//===----------------------------------------------------------------------===// 1258// Functions for determining if a loop was executed 0 times. 1259//===----------------------------------------------------------------------===// 1260 1261/// Return true if the terminator is a loop and the destination is the 1262/// false branch. 1263static bool isLoopJumpPastBody(const Stmt *Term, const BlockEdge *BE) { 1264 switch (Term->getStmtClass()) { 1265 case Stmt::ForStmtClass: 1266 case Stmt::WhileStmtClass: 1267 case Stmt::ObjCForCollectionStmtClass: 1268 break; 1269 default: 1270 // Note that we intentionally do not include do..while here. 1271 return false; 1272 } 1273 1274 // Did we take the false branch? 1275 const CFGBlock *Src = BE->getSrc(); 1276 assert(Src->succ_size() == 2); 1277 return (*(Src->succ_begin()+1) == BE->getDst()); 1278} 1279 1280static bool isContainedByStmt(ParentMap &PM, const Stmt *S, const Stmt *SubS) { 1281 while (SubS) { 1282 if (SubS == S) 1283 return true; 1284 SubS = PM.getParent(SubS); 1285 } 1286 return false; 1287} 1288 1289static const Stmt *getStmtBeforeCond(ParentMap &PM, const Stmt *Term, 1290 const ExplodedNode *N) { 1291 while (N) { 1292 Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>(); 1293 if (SP) { 1294 const Stmt *S = SP->getStmt(); 1295 if (!isContainedByStmt(PM, Term, S)) 1296 return S; 1297 } 1298 N = N->getFirstPred(); 1299 } 1300 return 0; 1301} 1302 1303static bool isInLoopBody(ParentMap &PM, const Stmt *S, const Stmt *Term) { 1304 const Stmt *LoopBody = 0; 1305 switch (Term->getStmtClass()) { 1306 case Stmt::ForStmtClass: { 1307 const ForStmt *FS = cast<ForStmt>(Term); 1308 if (isContainedByStmt(PM, FS->getInc(), S)) 1309 return true; 1310 LoopBody = FS->getBody(); 1311 break; 1312 } 1313 case Stmt::ObjCForCollectionStmtClass: { 1314 const ObjCForCollectionStmt *FC = cast<ObjCForCollectionStmt>(Term); 1315 LoopBody = FC->getBody(); 1316 break; 1317 } 1318 case Stmt::WhileStmtClass: 1319 LoopBody = cast<WhileStmt>(Term)->getBody(); 1320 break; 1321 default: 1322 return false; 1323 } 1324 return isContainedByStmt(PM, LoopBody, S); 1325} 1326 1327//===----------------------------------------------------------------------===// 1328// Top-level logic for generating extensive path diagnostics. 1329//===----------------------------------------------------------------------===// 1330 1331static bool GenerateExtensivePathDiagnostic(PathDiagnostic& PD, 1332 PathDiagnosticBuilder &PDB, 1333 const ExplodedNode *N, 1334 LocationContextMap &LCM, 1335 ArrayRef<BugReporterVisitor *> visitors) { 1336 EdgeBuilder EB(PD, PDB); 1337 const SourceManager& SM = PDB.getSourceManager(); 1338 StackDiagVector CallStack; 1339 InterestingExprs IE; 1340 1341 const ExplodedNode *NextNode = N->pred_empty() ? NULL : *(N->pred_begin()); 1342 while (NextNode) { 1343 N = NextNode; 1344 NextNode = N->getFirstPred(); 1345 ProgramPoint P = N->getLocation(); 1346 1347 do { 1348 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1349 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1350 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1351 N->getState().getPtr(), Ex, 1352 N->getLocationContext()); 1353 } 1354 1355 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1356 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1357 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1358 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1359 N->getState().getPtr(), Ex, 1360 N->getLocationContext()); 1361 } 1362 1363 PathDiagnosticCallPiece *C = 1364 PathDiagnosticCallPiece::construct(N, *CE, SM); 1365 LCM[C] = CE->getCalleeContext(); 1366 1367 EB.addEdge(C->callReturn, /*AlwaysAdd=*/true, /*IsPostJump=*/true); 1368 EB.flushLocations(); 1369 1370 PD.getActivePath().push_front(C); 1371 PD.pushActivePath(&C->path); 1372 CallStack.push_back(StackDiagPair(C, N)); 1373 break; 1374 } 1375 1376 // Pop the call hierarchy if we are done walking the contents 1377 // of a function call. 1378 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1379 // Add an edge to the start of the function. 1380 const Decl *D = CE->getCalleeContext()->getDecl(); 1381 PathDiagnosticLocation pos = 1382 PathDiagnosticLocation::createBegin(D, SM); 1383 EB.addEdge(pos); 1384 1385 // Flush all locations, and pop the active path. 1386 bool VisitedEntireCall = PD.isWithinCall(); 1387 EB.flushLocations(); 1388 PD.popActivePath(); 1389 PDB.LC = N->getLocationContext(); 1390 1391 // Either we just added a bunch of stuff to the top-level path, or 1392 // we have a previous CallExitEnd. If the former, it means that the 1393 // path terminated within a function call. We must then take the 1394 // current contents of the active path and place it within 1395 // a new PathDiagnosticCallPiece. 1396 PathDiagnosticCallPiece *C; 1397 if (VisitedEntireCall) { 1398 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 1399 } else { 1400 const Decl *Caller = CE->getLocationContext()->getDecl(); 1401 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1402 LCM[C] = CE->getCalleeContext(); 1403 } 1404 1405 C->setCallee(*CE, SM); 1406 EB.addContext(C->getLocation()); 1407 1408 if (!CallStack.empty()) { 1409 assert(CallStack.back().first == C); 1410 CallStack.pop_back(); 1411 } 1412 break; 1413 } 1414 1415 // Note that is important that we update the LocationContext 1416 // after looking at CallExits. CallExit basically adds an 1417 // edge in the *caller*, so we don't want to update the LocationContext 1418 // too soon. 1419 PDB.LC = N->getLocationContext(); 1420 1421 // Block edges. 1422 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1423 // Does this represent entering a call? If so, look at propagating 1424 // interesting symbols across call boundaries. 1425 if (NextNode) { 1426 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1427 const LocationContext *CalleeCtx = PDB.LC; 1428 if (CallerCtx != CalleeCtx) { 1429 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1430 N->getState().getPtr(), 1431 CalleeCtx, CallerCtx); 1432 } 1433 } 1434 1435 // Are we jumping to the head of a loop? Add a special diagnostic. 1436 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1437 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1438 const CompoundStmt *CS = NULL; 1439 1440 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1441 CS = dyn_cast<CompoundStmt>(FS->getBody()); 1442 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1443 CS = dyn_cast<CompoundStmt>(WS->getBody()); 1444 1445 PathDiagnosticEventPiece *p = 1446 new PathDiagnosticEventPiece(L, 1447 "Looping back to the head of the loop"); 1448 p->setPrunable(true); 1449 1450 EB.addEdge(p->getLocation(), true); 1451 PD.getActivePath().push_front(p); 1452 1453 if (CS) { 1454 PathDiagnosticLocation BL = 1455 PathDiagnosticLocation::createEndBrace(CS, SM); 1456 EB.addEdge(BL); 1457 } 1458 } 1459 1460 const CFGBlock *BSrc = BE->getSrc(); 1461 ParentMap &PM = PDB.getParentMap(); 1462 1463 if (const Stmt *Term = BSrc->getTerminator()) { 1464 // Are we jumping past the loop body without ever executing the 1465 // loop (because the condition was false)? 1466 if (isLoopJumpPastBody(Term, &*BE) && 1467 !isInLoopBody(PM, 1468 getStmtBeforeCond(PM, 1469 BSrc->getTerminatorCondition(), 1470 N), 1471 Term)) { 1472 PathDiagnosticLocation L(Term, SM, PDB.LC); 1473 PathDiagnosticEventPiece *PE = 1474 new PathDiagnosticEventPiece(L, "Loop body executed 0 times"); 1475 PE->setPrunable(true); 1476 1477 EB.addEdge(PE->getLocation(), true); 1478 PD.getActivePath().push_front(PE); 1479 } 1480 1481 // In any case, add the terminator as the current statement 1482 // context for control edges. 1483 EB.addContext(Term); 1484 } 1485 1486 break; 1487 } 1488 1489 if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) { 1490 Optional<CFGElement> First = BE->getFirstElement(); 1491 if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) { 1492 const Stmt *stmt = S->getStmt(); 1493 if (IsControlFlowExpr(stmt)) { 1494 // Add the proper context for '&&', '||', and '?'. 1495 EB.addContext(stmt); 1496 } 1497 else 1498 EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt()); 1499 } 1500 1501 break; 1502 } 1503 1504 1505 } while (0); 1506 1507 if (!NextNode) 1508 continue; 1509 1510 // Add pieces from custom visitors. 1511 BugReport *R = PDB.getBugReport(); 1512 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 1513 E = visitors.end(); 1514 I != E; ++I) { 1515 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) { 1516 const PathDiagnosticLocation &Loc = p->getLocation(); 1517 EB.addEdge(Loc, true); 1518 PD.getActivePath().push_front(p); 1519 updateStackPiecesWithMessage(p, CallStack); 1520 1521 if (const Stmt *S = Loc.asStmt()) 1522 EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 1523 } 1524 } 1525 } 1526 1527 return PDB.getBugReport()->isValid(); 1528} 1529 1530//===----------------------------------------------------------------------===// 1531// Methods for BugType and subclasses. 1532//===----------------------------------------------------------------------===// 1533BugType::~BugType() { } 1534 1535void BugType::FlushReports(BugReporter &BR) {} 1536 1537void BuiltinBug::anchor() {} 1538 1539//===----------------------------------------------------------------------===// 1540// Methods for BugReport and subclasses. 1541//===----------------------------------------------------------------------===// 1542 1543void BugReport::NodeResolver::anchor() {} 1544 1545void BugReport::addVisitor(BugReporterVisitor* visitor) { 1546 if (!visitor) 1547 return; 1548 1549 llvm::FoldingSetNodeID ID; 1550 visitor->Profile(ID); 1551 void *InsertPos; 1552 1553 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) { 1554 delete visitor; 1555 return; 1556 } 1557 1558 CallbacksSet.InsertNode(visitor, InsertPos); 1559 Callbacks.push_back(visitor); 1560 ++ConfigurationChangeToken; 1561} 1562 1563BugReport::~BugReport() { 1564 for (visitor_iterator I = visitor_begin(), E = visitor_end(); I != E; ++I) { 1565 delete *I; 1566 } 1567 while (!interestingSymbols.empty()) { 1568 popInterestingSymbolsAndRegions(); 1569 } 1570} 1571 1572const Decl *BugReport::getDeclWithIssue() const { 1573 if (DeclWithIssue) 1574 return DeclWithIssue; 1575 1576 const ExplodedNode *N = getErrorNode(); 1577 if (!N) 1578 return 0; 1579 1580 const LocationContext *LC = N->getLocationContext(); 1581 return LC->getCurrentStackFrame()->getDecl(); 1582} 1583 1584void BugReport::Profile(llvm::FoldingSetNodeID& hash) const { 1585 hash.AddPointer(&BT); 1586 hash.AddString(Description); 1587 PathDiagnosticLocation UL = getUniqueingLocation(); 1588 if (UL.isValid()) { 1589 UL.Profile(hash); 1590 } else if (Location.isValid()) { 1591 Location.Profile(hash); 1592 } else { 1593 assert(ErrorNode); 1594 hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode)); 1595 } 1596 1597 for (SmallVectorImpl<SourceRange>::const_iterator I = 1598 Ranges.begin(), E = Ranges.end(); I != E; ++I) { 1599 const SourceRange range = *I; 1600 if (!range.isValid()) 1601 continue; 1602 hash.AddInteger(range.getBegin().getRawEncoding()); 1603 hash.AddInteger(range.getEnd().getRawEncoding()); 1604 } 1605} 1606 1607void BugReport::markInteresting(SymbolRef sym) { 1608 if (!sym) 1609 return; 1610 1611 // If the symbol wasn't already in our set, note a configuration change. 1612 if (getInterestingSymbols().insert(sym).second) 1613 ++ConfigurationChangeToken; 1614 1615 if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym)) 1616 getInterestingRegions().insert(meta->getRegion()); 1617} 1618 1619void BugReport::markInteresting(const MemRegion *R) { 1620 if (!R) 1621 return; 1622 1623 // If the base region wasn't already in our set, note a configuration change. 1624 R = R->getBaseRegion(); 1625 if (getInterestingRegions().insert(R).second) 1626 ++ConfigurationChangeToken; 1627 1628 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1629 getInterestingSymbols().insert(SR->getSymbol()); 1630} 1631 1632void BugReport::markInteresting(SVal V) { 1633 markInteresting(V.getAsRegion()); 1634 markInteresting(V.getAsSymbol()); 1635} 1636 1637void BugReport::markInteresting(const LocationContext *LC) { 1638 if (!LC) 1639 return; 1640 InterestingLocationContexts.insert(LC); 1641} 1642 1643bool BugReport::isInteresting(SVal V) { 1644 return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol()); 1645} 1646 1647bool BugReport::isInteresting(SymbolRef sym) { 1648 if (!sym) 1649 return false; 1650 // We don't currently consider metadata symbols to be interesting 1651 // even if we know their region is interesting. Is that correct behavior? 1652 return getInterestingSymbols().count(sym); 1653} 1654 1655bool BugReport::isInteresting(const MemRegion *R) { 1656 if (!R) 1657 return false; 1658 R = R->getBaseRegion(); 1659 bool b = getInterestingRegions().count(R); 1660 if (b) 1661 return true; 1662 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 1663 return getInterestingSymbols().count(SR->getSymbol()); 1664 return false; 1665} 1666 1667bool BugReport::isInteresting(const LocationContext *LC) { 1668 if (!LC) 1669 return false; 1670 return InterestingLocationContexts.count(LC); 1671} 1672 1673void BugReport::lazyInitializeInterestingSets() { 1674 if (interestingSymbols.empty()) { 1675 interestingSymbols.push_back(new Symbols()); 1676 interestingRegions.push_back(new Regions()); 1677 } 1678} 1679 1680BugReport::Symbols &BugReport::getInterestingSymbols() { 1681 lazyInitializeInterestingSets(); 1682 return *interestingSymbols.back(); 1683} 1684 1685BugReport::Regions &BugReport::getInterestingRegions() { 1686 lazyInitializeInterestingSets(); 1687 return *interestingRegions.back(); 1688} 1689 1690void BugReport::pushInterestingSymbolsAndRegions() { 1691 interestingSymbols.push_back(new Symbols(getInterestingSymbols())); 1692 interestingRegions.push_back(new Regions(getInterestingRegions())); 1693} 1694 1695void BugReport::popInterestingSymbolsAndRegions() { 1696 delete interestingSymbols.back(); 1697 interestingSymbols.pop_back(); 1698 delete interestingRegions.back(); 1699 interestingRegions.pop_back(); 1700} 1701 1702const Stmt *BugReport::getStmt() const { 1703 if (!ErrorNode) 1704 return 0; 1705 1706 ProgramPoint ProgP = ErrorNode->getLocation(); 1707 const Stmt *S = NULL; 1708 1709 if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) { 1710 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit(); 1711 if (BE->getBlock() == &Exit) 1712 S = GetPreviousStmt(ErrorNode); 1713 } 1714 if (!S) 1715 S = PathDiagnosticLocation::getStmt(ErrorNode); 1716 1717 return S; 1718} 1719 1720std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator> 1721BugReport::getRanges() { 1722 // If no custom ranges, add the range of the statement corresponding to 1723 // the error node. 1724 if (Ranges.empty()) { 1725 if (const Expr *E = dyn_cast_or_null<Expr>(getStmt())) 1726 addRange(E->getSourceRange()); 1727 else 1728 return std::make_pair(ranges_iterator(), ranges_iterator()); 1729 } 1730 1731 // User-specified absence of range info. 1732 if (Ranges.size() == 1 && !Ranges.begin()->isValid()) 1733 return std::make_pair(ranges_iterator(), ranges_iterator()); 1734 1735 return std::make_pair(Ranges.begin(), Ranges.end()); 1736} 1737 1738PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const { 1739 if (ErrorNode) { 1740 assert(!Location.isValid() && 1741 "Either Location or ErrorNode should be specified but not both."); 1742 return PathDiagnosticLocation::createEndOfPath(ErrorNode, SM); 1743 } else { 1744 assert(Location.isValid()); 1745 return Location; 1746 } 1747 1748 return PathDiagnosticLocation(); 1749} 1750 1751//===----------------------------------------------------------------------===// 1752// Methods for BugReporter and subclasses. 1753//===----------------------------------------------------------------------===// 1754 1755BugReportEquivClass::~BugReportEquivClass() { } 1756GRBugReporter::~GRBugReporter() { } 1757BugReporterData::~BugReporterData() {} 1758 1759ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); } 1760 1761ProgramStateManager& 1762GRBugReporter::getStateManager() { return Eng.getStateManager(); } 1763 1764BugReporter::~BugReporter() { 1765 FlushReports(); 1766 1767 // Free the bug reports we are tracking. 1768 typedef std::vector<BugReportEquivClass *> ContTy; 1769 for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end(); 1770 I != E; ++I) { 1771 delete *I; 1772 } 1773} 1774 1775void BugReporter::FlushReports() { 1776 if (BugTypes.isEmpty()) 1777 return; 1778 1779 // First flush the warnings for each BugType. This may end up creating new 1780 // warnings and new BugTypes. 1781 // FIXME: Only NSErrorChecker needs BugType's FlushReports. 1782 // Turn NSErrorChecker into a proper checker and remove this. 1783 SmallVector<const BugType*, 16> bugTypes; 1784 for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I) 1785 bugTypes.push_back(*I); 1786 for (SmallVector<const BugType*, 16>::iterator 1787 I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I) 1788 const_cast<BugType*>(*I)->FlushReports(*this); 1789 1790 // We need to flush reports in deterministic order to ensure the order 1791 // of the reports is consistent between runs. 1792 typedef std::vector<BugReportEquivClass *> ContVecTy; 1793 for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end(); 1794 EI != EE; ++EI){ 1795 BugReportEquivClass& EQ = **EI; 1796 FlushReport(EQ); 1797 } 1798 1799 // BugReporter owns and deletes only BugTypes created implicitly through 1800 // EmitBasicReport. 1801 // FIXME: There are leaks from checkers that assume that the BugTypes they 1802 // create will be destroyed by the BugReporter. 1803 for (llvm::StringMap<BugType*>::iterator 1804 I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I) 1805 delete I->second; 1806 1807 // Remove all references to the BugType objects. 1808 BugTypes = F.getEmptySet(); 1809} 1810 1811//===----------------------------------------------------------------------===// 1812// PathDiagnostics generation. 1813//===----------------------------------------------------------------------===// 1814 1815namespace { 1816/// A wrapper around a report graph, which contains only a single path, and its 1817/// node maps. 1818class ReportGraph { 1819public: 1820 InterExplodedGraphMap BackMap; 1821 OwningPtr<ExplodedGraph> Graph; 1822 const ExplodedNode *ErrorNode; 1823 size_t Index; 1824}; 1825 1826/// A wrapper around a trimmed graph and its node maps. 1827class TrimmedGraph { 1828 InterExplodedGraphMap InverseMap; 1829 1830 typedef llvm::DenseMap<const ExplodedNode *, unsigned> PriorityMapTy; 1831 PriorityMapTy PriorityMap; 1832 1833 typedef std::pair<const ExplodedNode *, size_t> NodeIndexPair; 1834 SmallVector<NodeIndexPair, 32> ReportNodes; 1835 1836 OwningPtr<ExplodedGraph> G; 1837 1838 /// A helper class for sorting ExplodedNodes by priority. 1839 template <bool Descending> 1840 class PriorityCompare { 1841 const PriorityMapTy &PriorityMap; 1842 1843 public: 1844 PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {} 1845 1846 bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const { 1847 PriorityMapTy::const_iterator LI = PriorityMap.find(LHS); 1848 PriorityMapTy::const_iterator RI = PriorityMap.find(RHS); 1849 PriorityMapTy::const_iterator E = PriorityMap.end(); 1850 1851 if (LI == E) 1852 return Descending; 1853 if (RI == E) 1854 return !Descending; 1855 1856 return Descending ? LI->second > RI->second 1857 : LI->second < RI->second; 1858 } 1859 1860 bool operator()(const NodeIndexPair &LHS, const NodeIndexPair &RHS) const { 1861 return (*this)(LHS.first, RHS.first); 1862 } 1863 }; 1864 1865public: 1866 TrimmedGraph(const ExplodedGraph *OriginalGraph, 1867 ArrayRef<const ExplodedNode *> Nodes); 1868 1869 bool popNextReportGraph(ReportGraph &GraphWrapper); 1870}; 1871} 1872 1873TrimmedGraph::TrimmedGraph(const ExplodedGraph *OriginalGraph, 1874 ArrayRef<const ExplodedNode *> Nodes) { 1875 // The trimmed graph is created in the body of the constructor to ensure 1876 // that the DenseMaps have been initialized already. 1877 InterExplodedGraphMap ForwardMap; 1878 G.reset(OriginalGraph->trim(Nodes, &ForwardMap, &InverseMap)); 1879 1880 // Find the (first) error node in the trimmed graph. We just need to consult 1881 // the node map which maps from nodes in the original graph to nodes 1882 // in the new graph. 1883 llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes; 1884 1885 for (unsigned i = 0, count = Nodes.size(); i < count; ++i) { 1886 if (const ExplodedNode *NewNode = ForwardMap.lookup(Nodes[i])) { 1887 ReportNodes.push_back(std::make_pair(NewNode, i)); 1888 RemainingNodes.insert(NewNode); 1889 } 1890 } 1891 1892 assert(!RemainingNodes.empty() && "No error node found in the trimmed graph"); 1893 1894 // Perform a forward BFS to find all the shortest paths. 1895 std::queue<const ExplodedNode *> WS; 1896 1897 assert(G->num_roots() == 1); 1898 WS.push(*G->roots_begin()); 1899 unsigned Priority = 0; 1900 1901 while (!WS.empty()) { 1902 const ExplodedNode *Node = WS.front(); 1903 WS.pop(); 1904 1905 PriorityMapTy::iterator PriorityEntry; 1906 bool IsNew; 1907 llvm::tie(PriorityEntry, IsNew) = 1908 PriorityMap.insert(std::make_pair(Node, Priority)); 1909 ++Priority; 1910 1911 if (!IsNew) { 1912 assert(PriorityEntry->second <= Priority); 1913 continue; 1914 } 1915 1916 if (RemainingNodes.erase(Node)) 1917 if (RemainingNodes.empty()) 1918 break; 1919 1920 for (ExplodedNode::const_pred_iterator I = Node->succ_begin(), 1921 E = Node->succ_end(); 1922 I != E; ++I) 1923 WS.push(*I); 1924 } 1925 1926 // Sort the error paths from longest to shortest. 1927 std::sort(ReportNodes.begin(), ReportNodes.end(), 1928 PriorityCompare<true>(PriorityMap)); 1929} 1930 1931bool TrimmedGraph::popNextReportGraph(ReportGraph &GraphWrapper) { 1932 if (ReportNodes.empty()) 1933 return false; 1934 1935 const ExplodedNode *OrigN; 1936 llvm::tie(OrigN, GraphWrapper.Index) = ReportNodes.pop_back_val(); 1937 assert(PriorityMap.find(OrigN) != PriorityMap.end() && 1938 "error node not accessible from root"); 1939 1940 // Create a new graph with a single path. This is the graph 1941 // that will be returned to the caller. 1942 ExplodedGraph *GNew = new ExplodedGraph(); 1943 GraphWrapper.Graph.reset(GNew); 1944 GraphWrapper.BackMap.clear(); 1945 1946 // Now walk from the error node up the BFS path, always taking the 1947 // predeccessor with the lowest number. 1948 ExplodedNode *Succ = 0; 1949 while (true) { 1950 // Create the equivalent node in the new graph with the same state 1951 // and location. 1952 ExplodedNode *NewN = GNew->getNode(OrigN->getLocation(), OrigN->getState(), 1953 OrigN->isSink()); 1954 1955 // Store the mapping to the original node. 1956 InterExplodedGraphMap::const_iterator IMitr = InverseMap.find(OrigN); 1957 assert(IMitr != InverseMap.end() && "No mapping to original node."); 1958 GraphWrapper.BackMap[NewN] = IMitr->second; 1959 1960 // Link up the new node with the previous node. 1961 if (Succ) 1962 Succ->addPredecessor(NewN, *GNew); 1963 else 1964 GraphWrapper.ErrorNode = NewN; 1965 1966 Succ = NewN; 1967 1968 // Are we at the final node? 1969 if (OrigN->pred_empty()) { 1970 GNew->addRoot(NewN); 1971 break; 1972 } 1973 1974 // Find the next predeccessor node. We choose the node that is marked 1975 // with the lowest BFS number. 1976 OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(), 1977 PriorityCompare<false>(PriorityMap)); 1978 } 1979 1980 return true; 1981} 1982 1983 1984/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object 1985/// and collapses PathDiagosticPieces that are expanded by macros. 1986static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) { 1987 typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>, 1988 SourceLocation> > MacroStackTy; 1989 1990 typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> > 1991 PiecesTy; 1992 1993 MacroStackTy MacroStack; 1994 PiecesTy Pieces; 1995 1996 for (PathPieces::const_iterator I = path.begin(), E = path.end(); 1997 I!=E; ++I) { 1998 1999 PathDiagnosticPiece *piece = I->getPtr(); 2000 2001 // Recursively compact calls. 2002 if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){ 2003 CompactPathDiagnostic(call->path, SM); 2004 } 2005 2006 // Get the location of the PathDiagnosticPiece. 2007 const FullSourceLoc Loc = piece->getLocation().asLocation(); 2008 2009 // Determine the instantiation location, which is the location we group 2010 // related PathDiagnosticPieces. 2011 SourceLocation InstantiationLoc = Loc.isMacroID() ? 2012 SM.getExpansionLoc(Loc) : 2013 SourceLocation(); 2014 2015 if (Loc.isFileID()) { 2016 MacroStack.clear(); 2017 Pieces.push_back(piece); 2018 continue; 2019 } 2020 2021 assert(Loc.isMacroID()); 2022 2023 // Is the PathDiagnosticPiece within the same macro group? 2024 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) { 2025 MacroStack.back().first->subPieces.push_back(piece); 2026 continue; 2027 } 2028 2029 // We aren't in the same group. Are we descending into a new macro 2030 // or are part of an old one? 2031 IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup; 2032 2033 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ? 2034 SM.getExpansionLoc(Loc) : 2035 SourceLocation(); 2036 2037 // Walk the entire macro stack. 2038 while (!MacroStack.empty()) { 2039 if (InstantiationLoc == MacroStack.back().second) { 2040 MacroGroup = MacroStack.back().first; 2041 break; 2042 } 2043 2044 if (ParentInstantiationLoc == MacroStack.back().second) { 2045 MacroGroup = MacroStack.back().first; 2046 break; 2047 } 2048 2049 MacroStack.pop_back(); 2050 } 2051 2052 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) { 2053 // Create a new macro group and add it to the stack. 2054 PathDiagnosticMacroPiece *NewGroup = 2055 new PathDiagnosticMacroPiece( 2056 PathDiagnosticLocation::createSingleLocation(piece->getLocation())); 2057 2058 if (MacroGroup) 2059 MacroGroup->subPieces.push_back(NewGroup); 2060 else { 2061 assert(InstantiationLoc.isFileID()); 2062 Pieces.push_back(NewGroup); 2063 } 2064 2065 MacroGroup = NewGroup; 2066 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc)); 2067 } 2068 2069 // Finally, add the PathDiagnosticPiece to the group. 2070 MacroGroup->subPieces.push_back(piece); 2071 } 2072 2073 // Now take the pieces and construct a new PathDiagnostic. 2074 path.clear(); 2075 2076 for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I) 2077 path.push_back(*I); 2078} 2079 2080bool GRBugReporter::generatePathDiagnostic(PathDiagnostic& PD, 2081 PathDiagnosticConsumer &PC, 2082 ArrayRef<BugReport *> &bugReports) { 2083 assert(!bugReports.empty()); 2084 2085 bool HasValid = false; 2086 bool HasInvalid = false; 2087 SmallVector<const ExplodedNode *, 32> errorNodes; 2088 for (ArrayRef<BugReport*>::iterator I = bugReports.begin(), 2089 E = bugReports.end(); I != E; ++I) { 2090 if ((*I)->isValid()) { 2091 HasValid = true; 2092 errorNodes.push_back((*I)->getErrorNode()); 2093 } else { 2094 // Keep the errorNodes list in sync with the bugReports list. 2095 HasInvalid = true; 2096 errorNodes.push_back(0); 2097 } 2098 } 2099 2100 // If all the reports have been marked invalid by a previous path generation, 2101 // we're done. 2102 if (!HasValid) 2103 return false; 2104 2105 typedef PathDiagnosticConsumer::PathGenerationScheme PathGenerationScheme; 2106 PathGenerationScheme ActiveScheme = PC.getGenerationScheme(); 2107 2108 TrimmedGraph TrimG(&getGraph(), errorNodes); 2109 ReportGraph ErrorGraph; 2110 2111 while (TrimG.popNextReportGraph(ErrorGraph)) { 2112 // Find the BugReport with the original location. 2113 assert(ErrorGraph.Index < bugReports.size()); 2114 BugReport *R = bugReports[ErrorGraph.Index]; 2115 assert(R && "No original report found for sliced graph."); 2116 assert(R->isValid() && "Report selected by trimmed graph marked invalid."); 2117 2118 // Start building the path diagnostic... 2119 PathDiagnosticBuilder PDB(*this, R, ErrorGraph.BackMap, &PC); 2120 const ExplodedNode *N = ErrorGraph.ErrorNode; 2121 2122 // Register additional node visitors. 2123 R->addVisitor(new NilReceiverBRVisitor()); 2124 R->addVisitor(new ConditionBRVisitor()); 2125 R->addVisitor(new LikelyFalsePositiveSuppressionBRVisitor()); 2126 2127 BugReport::VisitorList visitors; 2128 unsigned origReportConfigToken, finalReportConfigToken; 2129 LocationContextMap LCM; 2130 2131 // While generating diagnostics, it's possible the visitors will decide 2132 // new symbols and regions are interesting, or add other visitors based on 2133 // the information they find. If they do, we need to regenerate the path 2134 // based on our new report configuration. 2135 do { 2136 // Get a clean copy of all the visitors. 2137 for (BugReport::visitor_iterator I = R->visitor_begin(), 2138 E = R->visitor_end(); I != E; ++I) 2139 visitors.push_back((*I)->clone()); 2140 2141 // Clear out the active path from any previous work. 2142 PD.resetPath(); 2143 origReportConfigToken = R->getConfigurationChangeToken(); 2144 2145 // Generate the very last diagnostic piece - the piece is visible before 2146 // the trace is expanded. 2147 PathDiagnosticPiece *LastPiece = 0; 2148 for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end(); 2149 I != E; ++I) { 2150 if (PathDiagnosticPiece *Piece = (*I)->getEndPath(PDB, N, *R)) { 2151 assert (!LastPiece && 2152 "There can only be one final piece in a diagnostic."); 2153 LastPiece = Piece; 2154 } 2155 } 2156 2157 if (ActiveScheme != PathDiagnosticConsumer::None) { 2158 if (!LastPiece) 2159 LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R); 2160 assert(LastPiece); 2161 PD.setEndOfPath(LastPiece); 2162 } 2163 2164 switch (ActiveScheme) { 2165 case PathDiagnosticConsumer::Extensive: 2166 GenerateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 2167 break; 2168 case PathDiagnosticConsumer::Minimal: 2169 GenerateMinimalPathDiagnostic(PD, PDB, N, LCM, visitors); 2170 break; 2171 case PathDiagnosticConsumer::None: 2172 GenerateVisitorsOnlyPathDiagnostic(PD, PDB, N, visitors); 2173 break; 2174 } 2175 2176 // Clean up the visitors we used. 2177 llvm::DeleteContainerPointers(visitors); 2178 2179 // Did anything change while generating this path? 2180 finalReportConfigToken = R->getConfigurationChangeToken(); 2181 } while (finalReportConfigToken != origReportConfigToken); 2182 2183 if (!R->isValid()) 2184 continue; 2185 2186 // Finally, prune the diagnostic path of uninteresting stuff. 2187 if (!PD.path.empty()) { 2188 // Remove messages that are basically the same. 2189 removeRedundantMsgs(PD.getMutablePieces()); 2190 2191 if (R->shouldPrunePath() && 2192 getEngine().getAnalysisManager().options.shouldPrunePaths()) { 2193 bool stillHasNotes = removeUnneededCalls(PD.getMutablePieces(), R, LCM); 2194 assert(stillHasNotes); 2195 (void)stillHasNotes; 2196 } 2197 2198 adjustCallLocations(PD.getMutablePieces()); 2199 } 2200 2201 // We found a report and didn't suppress it. 2202 return true; 2203 } 2204 2205 // We suppressed all the reports in this equivalence class. 2206 assert(!HasInvalid && "Inconsistent suppression"); 2207 (void)HasInvalid; 2208 return false; 2209} 2210 2211void BugReporter::Register(BugType *BT) { 2212 BugTypes = F.add(BugTypes, BT); 2213} 2214 2215void BugReporter::emitReport(BugReport* R) { 2216 // Compute the bug report's hash to determine its equivalence class. 2217 llvm::FoldingSetNodeID ID; 2218 R->Profile(ID); 2219 2220 // Lookup the equivance class. If there isn't one, create it. 2221 BugType& BT = R->getBugType(); 2222 Register(&BT); 2223 void *InsertPos; 2224 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos); 2225 2226 if (!EQ) { 2227 EQ = new BugReportEquivClass(R); 2228 EQClasses.InsertNode(EQ, InsertPos); 2229 EQClassesVector.push_back(EQ); 2230 } 2231 else 2232 EQ->AddReport(R); 2233} 2234 2235 2236//===----------------------------------------------------------------------===// 2237// Emitting reports in equivalence classes. 2238//===----------------------------------------------------------------------===// 2239 2240namespace { 2241struct FRIEC_WLItem { 2242 const ExplodedNode *N; 2243 ExplodedNode::const_succ_iterator I, E; 2244 2245 FRIEC_WLItem(const ExplodedNode *n) 2246 : N(n), I(N->succ_begin()), E(N->succ_end()) {} 2247}; 2248} 2249 2250static BugReport * 2251FindReportInEquivalenceClass(BugReportEquivClass& EQ, 2252 SmallVectorImpl<BugReport*> &bugReports) { 2253 2254 BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end(); 2255 assert(I != E); 2256 BugType& BT = I->getBugType(); 2257 2258 // If we don't need to suppress any of the nodes because they are 2259 // post-dominated by a sink, simply add all the nodes in the equivalence class 2260 // to 'Nodes'. Any of the reports will serve as a "representative" report. 2261 if (!BT.isSuppressOnSink()) { 2262 BugReport *R = I; 2263 for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) { 2264 const ExplodedNode *N = I->getErrorNode(); 2265 if (N) { 2266 R = I; 2267 bugReports.push_back(R); 2268 } 2269 } 2270 return R; 2271 } 2272 2273 // For bug reports that should be suppressed when all paths are post-dominated 2274 // by a sink node, iterate through the reports in the equivalence class 2275 // until we find one that isn't post-dominated (if one exists). We use a 2276 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write 2277 // this as a recursive function, but we don't want to risk blowing out the 2278 // stack for very long paths. 2279 BugReport *exampleReport = 0; 2280 2281 for (; I != E; ++I) { 2282 const ExplodedNode *errorNode = I->getErrorNode(); 2283 2284 if (!errorNode) 2285 continue; 2286 if (errorNode->isSink()) { 2287 llvm_unreachable( 2288 "BugType::isSuppressSink() should not be 'true' for sink end nodes"); 2289 } 2290 // No successors? By definition this nodes isn't post-dominated by a sink. 2291 if (errorNode->succ_empty()) { 2292 bugReports.push_back(I); 2293 if (!exampleReport) 2294 exampleReport = I; 2295 continue; 2296 } 2297 2298 // Make sure we get a clean location context map so we don't 2299 // hold onto old mappings. 2300 LCM.clear(); 2301 2302 // At this point we know that 'N' is not a sink and it has at least one 2303 // successor. Use a DFS worklist to find a non-sink end-of-path node. 2304 typedef FRIEC_WLItem WLItem; 2305 typedef SmallVector<WLItem, 10> DFSWorkList; 2306 llvm::DenseMap<const ExplodedNode *, unsigned> Visited; 2307 2308 DFSWorkList WL; 2309 WL.push_back(errorNode); 2310 Visited[errorNode] = 1; 2311 2312 while (!WL.empty()) { 2313 WLItem &WI = WL.back(); 2314 assert(!WI.N->succ_empty()); 2315 2316 for (; WI.I != WI.E; ++WI.I) { 2317 const ExplodedNode *Succ = *WI.I; 2318 // End-of-path node? 2319 if (Succ->succ_empty()) { 2320 // If we found an end-of-path node that is not a sink. 2321 if (!Succ->isSink()) { 2322 bugReports.push_back(I); 2323 if (!exampleReport) 2324 exampleReport = I; 2325 WL.clear(); 2326 break; 2327 } 2328 // Found a sink? Continue on to the next successor. 2329 continue; 2330 } 2331 // Mark the successor as visited. If it hasn't been explored, 2332 // enqueue it to the DFS worklist. 2333 unsigned &mark = Visited[Succ]; 2334 if (!mark) { 2335 mark = 1; 2336 WL.push_back(Succ); 2337 break; 2338 } 2339 } 2340 2341 // The worklist may have been cleared at this point. First 2342 // check if it is empty before checking the last item. 2343 if (!WL.empty() && &WL.back() == &WI) 2344 WL.pop_back(); 2345 } 2346 } 2347 2348 // ExampleReport will be NULL if all the nodes in the equivalence class 2349 // were post-dominated by sinks. 2350 return exampleReport; 2351} 2352 2353void BugReporter::FlushReport(BugReportEquivClass& EQ) { 2354 SmallVector<BugReport*, 10> bugReports; 2355 BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports); 2356 if (exampleReport) { 2357 const PathDiagnosticConsumers &C = getPathDiagnosticConsumers(); 2358 for (PathDiagnosticConsumers::const_iterator I=C.begin(), 2359 E=C.end(); I != E; ++I) { 2360 FlushReport(exampleReport, **I, bugReports); 2361 } 2362 } 2363} 2364 2365void BugReporter::FlushReport(BugReport *exampleReport, 2366 PathDiagnosticConsumer &PD, 2367 ArrayRef<BugReport*> bugReports) { 2368 2369 // FIXME: Make sure we use the 'R' for the path that was actually used. 2370 // Probably doesn't make a difference in practice. 2371 BugType& BT = exampleReport->getBugType(); 2372 2373 OwningPtr<PathDiagnostic> 2374 D(new PathDiagnostic(exampleReport->getDeclWithIssue(), 2375 exampleReport->getBugType().getName(), 2376 exampleReport->getDescription(), 2377 exampleReport->getShortDescription(/*Fallback=*/false), 2378 BT.getCategory(), 2379 exampleReport->getUniqueingLocation(), 2380 exampleReport->getUniqueingDecl())); 2381 2382 MaxBugClassSize = std::max(bugReports.size(), 2383 static_cast<size_t>(MaxBugClassSize)); 2384 2385 // Generate the full path diagnostic, using the generation scheme 2386 // specified by the PathDiagnosticConsumer. Note that we have to generate 2387 // path diagnostics even for consumers which do not support paths, because 2388 // the BugReporterVisitors may mark this bug as a false positive. 2389 if (!bugReports.empty()) 2390 if (!generatePathDiagnostic(*D.get(), PD, bugReports)) 2391 return; 2392 2393 MaxValidBugClassSize = std::max(bugReports.size(), 2394 static_cast<size_t>(MaxValidBugClassSize)); 2395 2396 // If the path is empty, generate a single step path with the location 2397 // of the issue. 2398 if (D->path.empty()) { 2399 PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager()); 2400 PathDiagnosticPiece *piece = 2401 new PathDiagnosticEventPiece(L, exampleReport->getDescription()); 2402 BugReport::ranges_iterator Beg, End; 2403 llvm::tie(Beg, End) = exampleReport->getRanges(); 2404 for ( ; Beg != End; ++Beg) 2405 piece->addRange(*Beg); 2406 D->setEndOfPath(piece); 2407 } 2408 2409 // Get the meta data. 2410 const BugReport::ExtraTextList &Meta = exampleReport->getExtraText(); 2411 for (BugReport::ExtraTextList::const_iterator i = Meta.begin(), 2412 e = Meta.end(); i != e; ++i) { 2413 D->addMeta(*i); 2414 } 2415 2416 PD.HandlePathDiagnostic(D.take()); 2417} 2418 2419void BugReporter::EmitBasicReport(const Decl *DeclWithIssue, 2420 StringRef name, 2421 StringRef category, 2422 StringRef str, PathDiagnosticLocation Loc, 2423 SourceRange* RBeg, unsigned NumRanges) { 2424 2425 // 'BT' is owned by BugReporter. 2426 BugType *BT = getBugTypeForName(name, category); 2427 BugReport *R = new BugReport(*BT, str, Loc); 2428 R->setDeclWithIssue(DeclWithIssue); 2429 for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg); 2430 emitReport(R); 2431} 2432 2433BugType *BugReporter::getBugTypeForName(StringRef name, 2434 StringRef category) { 2435 SmallString<136> fullDesc; 2436 llvm::raw_svector_ostream(fullDesc) << name << ":" << category; 2437 llvm::StringMapEntry<BugType *> & 2438 entry = StrBugTypes.GetOrCreateValue(fullDesc); 2439 BugType *BT = entry.getValue(); 2440 if (!BT) { 2441 BT = new BugType(name, category); 2442 entry.setValue(BT); 2443 } 2444 return BT; 2445} 2446