BugReporter.cpp revision 96b8134337883908fcc45484486fe200d6b3e32f
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 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 PathPieces *, 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->path)); 177 if (R->isInteresting(LCM[&call->path])) { 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->path] = 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->path] = 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 884static PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L, 885 const LocationContext *LC, 886 bool firstCharOnly = false) { 887 if (const Stmt *S = L.asStmt()) { 888 const Stmt *Original = S; 889 while (1) { 890 // Adjust the location for some expressions that are best referenced 891 // by one of their subexpressions. 892 switch (S->getStmtClass()) { 893 default: 894 break; 895 case Stmt::ParenExprClass: 896 case Stmt::GenericSelectionExprClass: 897 S = cast<Expr>(S)->IgnoreParens(); 898 firstCharOnly = true; 899 continue; 900 case Stmt::BinaryConditionalOperatorClass: 901 case Stmt::ConditionalOperatorClass: 902 S = cast<AbstractConditionalOperator>(S)->getCond(); 903 firstCharOnly = true; 904 continue; 905 case Stmt::ChooseExprClass: 906 S = cast<ChooseExpr>(S)->getCond(); 907 firstCharOnly = true; 908 continue; 909 case Stmt::BinaryOperatorClass: 910 S = cast<BinaryOperator>(S)->getLHS(); 911 firstCharOnly = true; 912 continue; 913 } 914 915 break; 916 } 917 918 if (S != Original) 919 L = PathDiagnosticLocation(S, L.getManager(), LC); 920 } 921 922 if (firstCharOnly) 923 L = PathDiagnosticLocation::createSingleLocation(L); 924 925 return L; 926} 927 928class EdgeBuilder { 929 std::vector<ContextLocation> CLocs; 930 typedef std::vector<ContextLocation>::iterator iterator; 931 PathDiagnostic &PD; 932 PathDiagnosticBuilder &PDB; 933 PathDiagnosticLocation PrevLoc; 934 935 bool IsConsumedExpr(const PathDiagnosticLocation &L); 936 937 bool containsLocation(const PathDiagnosticLocation &Container, 938 const PathDiagnosticLocation &Containee); 939 940 PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L); 941 942 943 944 void popLocation() { 945 if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) { 946 // For contexts, we only one the first character as the range. 947 rawAddEdge(cleanUpLocation(CLocs.back(), PDB.LC, true)); 948 } 949 CLocs.pop_back(); 950 } 951 952public: 953 EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb) 954 : PD(pd), PDB(pdb) { 955 956 // If the PathDiagnostic already has pieces, add the enclosing statement 957 // of the first piece as a context as well. 958 if (!PD.path.empty()) { 959 PrevLoc = (*PD.path.begin())->getLocation(); 960 961 if (const Stmt *S = PrevLoc.asStmt()) 962 addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 963 } 964 } 965 966 ~EdgeBuilder() { 967 while (!CLocs.empty()) popLocation(); 968 969 // Finally, add an initial edge from the start location of the first 970 // statement (if it doesn't already exist). 971 PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin( 972 PDB.LC, 973 PDB.getSourceManager()); 974 if (L.isValid()) 975 rawAddEdge(L); 976 } 977 978 void flushLocations() { 979 while (!CLocs.empty()) 980 popLocation(); 981 PrevLoc = PathDiagnosticLocation(); 982 } 983 984 void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false, 985 bool IsPostJump = false); 986 987 void rawAddEdge(PathDiagnosticLocation NewLoc); 988 989 void addContext(const Stmt *S); 990 void addContext(const PathDiagnosticLocation &L); 991 void addExtendedContext(const Stmt *S); 992}; 993} // end anonymous namespace 994 995 996PathDiagnosticLocation 997EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) { 998 if (const Stmt *S = L.asStmt()) { 999 if (IsControlFlowExpr(S)) 1000 return L; 1001 1002 return PDB.getEnclosingStmtLocation(S); 1003 } 1004 1005 return L; 1006} 1007 1008bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container, 1009 const PathDiagnosticLocation &Containee) { 1010 1011 if (Container == Containee) 1012 return true; 1013 1014 if (Container.asDecl()) 1015 return true; 1016 1017 if (const Stmt *S = Containee.asStmt()) 1018 if (const Stmt *ContainerS = Container.asStmt()) { 1019 while (S) { 1020 if (S == ContainerS) 1021 return true; 1022 S = PDB.getParent(S); 1023 } 1024 return false; 1025 } 1026 1027 // Less accurate: compare using source ranges. 1028 SourceRange ContainerR = Container.asRange(); 1029 SourceRange ContaineeR = Containee.asRange(); 1030 1031 SourceManager &SM = PDB.getSourceManager(); 1032 SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin()); 1033 SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd()); 1034 SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin()); 1035 SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd()); 1036 1037 unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg); 1038 unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd); 1039 unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg); 1040 unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd); 1041 1042 assert(ContainerBegLine <= ContainerEndLine); 1043 assert(ContaineeBegLine <= ContaineeEndLine); 1044 1045 return (ContainerBegLine <= ContaineeBegLine && 1046 ContainerEndLine >= ContaineeEndLine && 1047 (ContainerBegLine != ContaineeBegLine || 1048 SM.getExpansionColumnNumber(ContainerRBeg) <= 1049 SM.getExpansionColumnNumber(ContaineeRBeg)) && 1050 (ContainerEndLine != ContaineeEndLine || 1051 SM.getExpansionColumnNumber(ContainerREnd) >= 1052 SM.getExpansionColumnNumber(ContaineeREnd))); 1053} 1054 1055void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) { 1056 if (!PrevLoc.isValid()) { 1057 PrevLoc = NewLoc; 1058 return; 1059 } 1060 1061 const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc, PDB.LC); 1062 const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc, PDB.LC); 1063 1064 if (PrevLocClean.asLocation().isInvalid()) { 1065 PrevLoc = NewLoc; 1066 return; 1067 } 1068 1069 if (NewLocClean.asLocation() == PrevLocClean.asLocation()) 1070 return; 1071 1072 // FIXME: Ignore intra-macro edges for now. 1073 if (NewLocClean.asLocation().getExpansionLoc() == 1074 PrevLocClean.asLocation().getExpansionLoc()) 1075 return; 1076 1077 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean)); 1078 PrevLoc = NewLoc; 1079} 1080 1081void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd, 1082 bool IsPostJump) { 1083 1084 if (!alwaysAdd && NewLoc.asLocation().isMacroID()) 1085 return; 1086 1087 const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc); 1088 1089 while (!CLocs.empty()) { 1090 ContextLocation &TopContextLoc = CLocs.back(); 1091 1092 // Is the top location context the same as the one for the new location? 1093 if (TopContextLoc == CLoc) { 1094 if (alwaysAdd) { 1095 if (IsConsumedExpr(TopContextLoc)) 1096 TopContextLoc.markDead(); 1097 1098 rawAddEdge(NewLoc); 1099 } 1100 1101 if (IsPostJump) 1102 TopContextLoc.markDead(); 1103 return; 1104 } 1105 1106 if (containsLocation(TopContextLoc, CLoc)) { 1107 if (alwaysAdd) { 1108 rawAddEdge(NewLoc); 1109 1110 if (IsConsumedExpr(CLoc)) { 1111 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/true)); 1112 return; 1113 } 1114 } 1115 1116 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/IsPostJump)); 1117 return; 1118 } 1119 1120 // Context does not contain the location. Flush it. 1121 popLocation(); 1122 } 1123 1124 // If we reach here, there is no enclosing context. Just add the edge. 1125 rawAddEdge(NewLoc); 1126} 1127 1128bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) { 1129 if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt())) 1130 return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X); 1131 1132 return false; 1133} 1134 1135void EdgeBuilder::addExtendedContext(const Stmt *S) { 1136 if (!S) 1137 return; 1138 1139 const Stmt *Parent = PDB.getParent(S); 1140 while (Parent) { 1141 if (isa<CompoundStmt>(Parent)) 1142 Parent = PDB.getParent(Parent); 1143 else 1144 break; 1145 } 1146 1147 if (Parent) { 1148 switch (Parent->getStmtClass()) { 1149 case Stmt::DoStmtClass: 1150 case Stmt::ObjCAtSynchronizedStmtClass: 1151 addContext(Parent); 1152 default: 1153 break; 1154 } 1155 } 1156 1157 addContext(S); 1158} 1159 1160void EdgeBuilder::addContext(const Stmt *S) { 1161 if (!S) 1162 return; 1163 1164 PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC); 1165 addContext(L); 1166} 1167 1168void EdgeBuilder::addContext(const PathDiagnosticLocation &L) { 1169 while (!CLocs.empty()) { 1170 const PathDiagnosticLocation &TopContextLoc = CLocs.back(); 1171 1172 // Is the top location context the same as the one for the new location? 1173 if (TopContextLoc == L) 1174 return; 1175 1176 if (containsLocation(TopContextLoc, L)) { 1177 CLocs.push_back(L); 1178 return; 1179 } 1180 1181 // Context does not contain the location. Flush it. 1182 popLocation(); 1183 } 1184 1185 CLocs.push_back(L); 1186} 1187 1188// Cone-of-influence: support the reverse propagation of "interesting" symbols 1189// and values by tracing interesting calculations backwards through evaluated 1190// expressions along a path. This is probably overly complicated, but the idea 1191// is that if an expression computed an "interesting" value, the child 1192// expressions are are also likely to be "interesting" as well (which then 1193// propagates to the values they in turn compute). This reverse propagation 1194// is needed to track interesting correlations across function call boundaries, 1195// where formal arguments bind to actual arguments, etc. This is also needed 1196// because the constraint solver sometimes simplifies certain symbolic values 1197// into constants when appropriate, and this complicates reasoning about 1198// interesting values. 1199typedef llvm::DenseSet<const Expr *> InterestingExprs; 1200 1201static void reversePropagateIntererstingSymbols(BugReport &R, 1202 InterestingExprs &IE, 1203 const ProgramState *State, 1204 const Expr *Ex, 1205 const LocationContext *LCtx) { 1206 SVal V = State->getSVal(Ex, LCtx); 1207 if (!(R.isInteresting(V) || IE.count(Ex))) 1208 return; 1209 1210 switch (Ex->getStmtClass()) { 1211 default: 1212 if (!isa<CastExpr>(Ex)) 1213 break; 1214 // Fall through. 1215 case Stmt::BinaryOperatorClass: 1216 case Stmt::UnaryOperatorClass: { 1217 for (Stmt::const_child_iterator CI = Ex->child_begin(), 1218 CE = Ex->child_end(); 1219 CI != CE; ++CI) { 1220 if (const Expr *child = dyn_cast_or_null<Expr>(*CI)) { 1221 IE.insert(child); 1222 SVal ChildV = State->getSVal(child, LCtx); 1223 R.markInteresting(ChildV); 1224 } 1225 break; 1226 } 1227 } 1228 } 1229 1230 R.markInteresting(V); 1231} 1232 1233static void reversePropagateInterestingSymbols(BugReport &R, 1234 InterestingExprs &IE, 1235 const ProgramState *State, 1236 const LocationContext *CalleeCtx, 1237 const LocationContext *CallerCtx) 1238{ 1239 // FIXME: Handle non-CallExpr-based CallEvents. 1240 const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame(); 1241 const Stmt *CallSite = Callee->getCallSite(); 1242 if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) { 1243 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) { 1244 FunctionDecl::param_const_iterator PI = FD->param_begin(), 1245 PE = FD->param_end(); 1246 CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end(); 1247 for (; AI != AE && PI != PE; ++AI, ++PI) { 1248 if (const Expr *ArgE = *AI) { 1249 if (const ParmVarDecl *PD = *PI) { 1250 Loc LV = State->getLValue(PD, CalleeCtx); 1251 if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV))) 1252 IE.insert(ArgE); 1253 } 1254 } 1255 } 1256 } 1257 } 1258} 1259 1260//===----------------------------------------------------------------------===// 1261// Functions for determining if a loop was executed 0 times. 1262//===----------------------------------------------------------------------===// 1263 1264static bool isLoop(const Stmt *Term) { 1265 switch (Term->getStmtClass()) { 1266 case Stmt::ForStmtClass: 1267 case Stmt::WhileStmtClass: 1268 case Stmt::ObjCForCollectionStmtClass: 1269 return true; 1270 default: 1271 // Note that we intentionally do not include do..while here. 1272 return false; 1273 } 1274} 1275 1276static bool isJumpToFalseBranch(const BlockEdge *BE) { 1277 const CFGBlock *Src = BE->getSrc(); 1278 assert(Src->succ_size() == 2); 1279 return (*(Src->succ_begin()+1) == BE->getDst()); 1280} 1281 1282/// Return true if the terminator is a loop and the destination is the 1283/// false branch. 1284static bool isLoopJumpPastBody(const Stmt *Term, const BlockEdge *BE) { 1285 if (!isLoop(Term)) 1286 return false; 1287 1288 // Did we take the false branch? 1289 return isJumpToFalseBranch(BE); 1290} 1291 1292static bool isContainedByStmt(ParentMap &PM, const Stmt *S, const Stmt *SubS) { 1293 while (SubS) { 1294 if (SubS == S) 1295 return true; 1296 SubS = PM.getParent(SubS); 1297 } 1298 return false; 1299} 1300 1301static const Stmt *getStmtBeforeCond(ParentMap &PM, const Stmt *Term, 1302 const ExplodedNode *N) { 1303 while (N) { 1304 Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>(); 1305 if (SP) { 1306 const Stmt *S = SP->getStmt(); 1307 if (!isContainedByStmt(PM, Term, S)) 1308 return S; 1309 } 1310 N = N->getFirstPred(); 1311 } 1312 return 0; 1313} 1314 1315static bool isInLoopBody(ParentMap &PM, const Stmt *S, const Stmt *Term) { 1316 const Stmt *LoopBody = 0; 1317 switch (Term->getStmtClass()) { 1318 case Stmt::ForStmtClass: { 1319 const ForStmt *FS = cast<ForStmt>(Term); 1320 if (isContainedByStmt(PM, FS->getInc(), S)) 1321 return true; 1322 LoopBody = FS->getBody(); 1323 break; 1324 } 1325 case Stmt::ObjCForCollectionStmtClass: { 1326 const ObjCForCollectionStmt *FC = cast<ObjCForCollectionStmt>(Term); 1327 LoopBody = FC->getBody(); 1328 break; 1329 } 1330 case Stmt::WhileStmtClass: 1331 LoopBody = cast<WhileStmt>(Term)->getBody(); 1332 break; 1333 default: 1334 return false; 1335 } 1336 return isContainedByStmt(PM, LoopBody, S); 1337} 1338 1339//===----------------------------------------------------------------------===// 1340// Top-level logic for generating extensive path diagnostics. 1341//===----------------------------------------------------------------------===// 1342 1343static bool GenerateExtensivePathDiagnostic(PathDiagnostic& PD, 1344 PathDiagnosticBuilder &PDB, 1345 const ExplodedNode *N, 1346 LocationContextMap &LCM, 1347 ArrayRef<BugReporterVisitor *> visitors) { 1348 EdgeBuilder EB(PD, PDB); 1349 const SourceManager& SM = PDB.getSourceManager(); 1350 StackDiagVector CallStack; 1351 InterestingExprs IE; 1352 1353 const ExplodedNode *NextNode = N->pred_empty() ? NULL : *(N->pred_begin()); 1354 while (NextNode) { 1355 N = NextNode; 1356 NextNode = N->getFirstPred(); 1357 ProgramPoint P = N->getLocation(); 1358 1359 do { 1360 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1361 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1362 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1363 N->getState().getPtr(), Ex, 1364 N->getLocationContext()); 1365 } 1366 1367 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1368 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1369 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1370 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1371 N->getState().getPtr(), Ex, 1372 N->getLocationContext()); 1373 } 1374 1375 PathDiagnosticCallPiece *C = 1376 PathDiagnosticCallPiece::construct(N, *CE, SM); 1377 LCM[&C->path] = CE->getCalleeContext(); 1378 1379 EB.addEdge(C->callReturn, /*AlwaysAdd=*/true, /*IsPostJump=*/true); 1380 EB.flushLocations(); 1381 1382 PD.getActivePath().push_front(C); 1383 PD.pushActivePath(&C->path); 1384 CallStack.push_back(StackDiagPair(C, N)); 1385 break; 1386 } 1387 1388 // Pop the call hierarchy if we are done walking the contents 1389 // of a function call. 1390 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1391 // Add an edge to the start of the function. 1392 const Decl *D = CE->getCalleeContext()->getDecl(); 1393 PathDiagnosticLocation pos = 1394 PathDiagnosticLocation::createBegin(D, SM); 1395 EB.addEdge(pos); 1396 1397 // Flush all locations, and pop the active path. 1398 bool VisitedEntireCall = PD.isWithinCall(); 1399 EB.flushLocations(); 1400 PD.popActivePath(); 1401 PDB.LC = N->getLocationContext(); 1402 1403 // Either we just added a bunch of stuff to the top-level path, or 1404 // we have a previous CallExitEnd. If the former, it means that the 1405 // path terminated within a function call. We must then take the 1406 // current contents of the active path and place it within 1407 // a new PathDiagnosticCallPiece. 1408 PathDiagnosticCallPiece *C; 1409 if (VisitedEntireCall) { 1410 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 1411 } else { 1412 const Decl *Caller = CE->getLocationContext()->getDecl(); 1413 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1414 LCM[&C->path] = CE->getCalleeContext(); 1415 } 1416 1417 C->setCallee(*CE, SM); 1418 EB.addContext(C->getLocation()); 1419 1420 if (!CallStack.empty()) { 1421 assert(CallStack.back().first == C); 1422 CallStack.pop_back(); 1423 } 1424 break; 1425 } 1426 1427 // Note that is important that we update the LocationContext 1428 // after looking at CallExits. CallExit basically adds an 1429 // edge in the *caller*, so we don't want to update the LocationContext 1430 // too soon. 1431 PDB.LC = N->getLocationContext(); 1432 1433 // Block edges. 1434 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1435 // Does this represent entering a call? If so, look at propagating 1436 // interesting symbols across call boundaries. 1437 if (NextNode) { 1438 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1439 const LocationContext *CalleeCtx = PDB.LC; 1440 if (CallerCtx != CalleeCtx) { 1441 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1442 N->getState().getPtr(), 1443 CalleeCtx, CallerCtx); 1444 } 1445 } 1446 1447 // Are we jumping to the head of a loop? Add a special diagnostic. 1448 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1449 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1450 const CompoundStmt *CS = NULL; 1451 1452 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1453 CS = dyn_cast<CompoundStmt>(FS->getBody()); 1454 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1455 CS = dyn_cast<CompoundStmt>(WS->getBody()); 1456 1457 PathDiagnosticEventPiece *p = 1458 new PathDiagnosticEventPiece(L, 1459 "Looping back to the head of the loop"); 1460 p->setPrunable(true); 1461 1462 EB.addEdge(p->getLocation(), true); 1463 PD.getActivePath().push_front(p); 1464 1465 if (CS) { 1466 PathDiagnosticLocation BL = 1467 PathDiagnosticLocation::createEndBrace(CS, SM); 1468 EB.addEdge(BL); 1469 } 1470 } 1471 1472 const CFGBlock *BSrc = BE->getSrc(); 1473 ParentMap &PM = PDB.getParentMap(); 1474 1475 if (const Stmt *Term = BSrc->getTerminator()) { 1476 // Are we jumping past the loop body without ever executing the 1477 // loop (because the condition was false)? 1478 if (isLoopJumpPastBody(Term, &*BE) && 1479 !isInLoopBody(PM, 1480 getStmtBeforeCond(PM, 1481 BSrc->getTerminatorCondition(), 1482 N), 1483 Term)) { 1484 PathDiagnosticLocation L(Term, SM, PDB.LC); 1485 PathDiagnosticEventPiece *PE = 1486 new PathDiagnosticEventPiece(L, "Loop body executed 0 times"); 1487 PE->setPrunable(true); 1488 1489 EB.addEdge(PE->getLocation(), true); 1490 PD.getActivePath().push_front(PE); 1491 } 1492 1493 // In any case, add the terminator as the current statement 1494 // context for control edges. 1495 EB.addContext(Term); 1496 } 1497 1498 break; 1499 } 1500 1501 if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) { 1502 Optional<CFGElement> First = BE->getFirstElement(); 1503 if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) { 1504 const Stmt *stmt = S->getStmt(); 1505 if (IsControlFlowExpr(stmt)) { 1506 // Add the proper context for '&&', '||', and '?'. 1507 EB.addContext(stmt); 1508 } 1509 else 1510 EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt()); 1511 } 1512 1513 break; 1514 } 1515 1516 1517 } while (0); 1518 1519 if (!NextNode) 1520 continue; 1521 1522 // Add pieces from custom visitors. 1523 BugReport *R = PDB.getBugReport(); 1524 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 1525 E = visitors.end(); 1526 I != E; ++I) { 1527 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) { 1528 const PathDiagnosticLocation &Loc = p->getLocation(); 1529 EB.addEdge(Loc, true); 1530 PD.getActivePath().push_front(p); 1531 updateStackPiecesWithMessage(p, CallStack); 1532 1533 if (const Stmt *S = Loc.asStmt()) 1534 EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 1535 } 1536 } 1537 } 1538 1539 return PDB.getBugReport()->isValid(); 1540} 1541 1542/// \brief Adds a sanitized control-flow diagnostic edge to a path. 1543static void addEdgeToPath(PathPieces &path, 1544 PathDiagnosticLocation &PrevLoc, 1545 PathDiagnosticLocation NewLoc, 1546 const LocationContext *LC) { 1547 if (!NewLoc.isValid()) 1548 return; 1549 1550 SourceLocation NewLocL = NewLoc.asLocation(); 1551 if (NewLocL.isInvalid() || NewLocL.isMacroID()) 1552 return; 1553 1554 if (!PrevLoc.isValid()) { 1555 PrevLoc = NewLoc; 1556 return; 1557 } 1558 1559 // FIXME: ignore intra-macro edges for now. 1560 if (NewLoc.asLocation().getExpansionLoc() == 1561 PrevLoc.asLocation().getExpansionLoc()) 1562 return; 1563 1564 path.push_front(new PathDiagnosticControlFlowPiece(NewLoc, 1565 PrevLoc)); 1566 PrevLoc = NewLoc; 1567} 1568 1569enum EventCategorization { EC_None, EC_EnterLoop, EC_LoopingBack }; 1570 1571typedef llvm::DenseMap<const PathDiagnosticEventPiece *, 1572 enum EventCategorization> 1573 EventCategoryMap; 1574 1575 1576static void pruneLoopEvents(PathPieces &path, EventCategoryMap &ECM) { 1577 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ++I) { 1578 if (PathDiagnosticCallPiece *call = dyn_cast<PathDiagnosticCallPiece>(*I)) { 1579 pruneLoopEvents(call->path, ECM); 1580 continue; 1581 } 1582 1583 PathDiagnosticEventPiece *I_event = dyn_cast<PathDiagnosticEventPiece>(*I); 1584 if (!I_event || ECM[I_event] != EC_LoopingBack) 1585 continue; 1586 1587 PathPieces::iterator Next = I; ++Next; 1588 PathDiagnosticEventPiece *Next_event = 0; 1589 for ( ; Next != E ; ++Next) { 1590 Next_event = dyn_cast<PathDiagnosticEventPiece>(*Next); 1591 if (Next_event) 1592 break; 1593 } 1594 1595 if (Next_event) { 1596 EventCategorization E = ECM[Next_event]; 1597 if (E == EC_EnterLoop) { 1598 PathDiagnosticLocation L = I_event->getLocation(); 1599 PathDiagnosticLocation L_next = Next_event->getLocation(); 1600 if (L == L_next) { 1601 path.erase(Next); 1602 } 1603 } 1604 } 1605 } 1606} 1607 1608static bool 1609GenerateAlternateExtensivePathDiagnostic(PathDiagnostic& PD, 1610 PathDiagnosticBuilder &PDB, 1611 const ExplodedNode *N, 1612 LocationContextMap &LCM, 1613 ArrayRef<BugReporterVisitor *> visitors) { 1614 1615 BugReport *report = PDB.getBugReport(); 1616 const SourceManager& SM = PDB.getSourceManager(); 1617 StackDiagVector CallStack; 1618 InterestingExprs IE; 1619 1620 // Record the last location for a given visited stack frame. 1621 llvm::DenseMap<const StackFrameContext *, PathDiagnosticLocation> 1622 PrevLocMap; 1623 1624 EventCategoryMap EventCategory; 1625 1626 const ExplodedNode *NextNode = N->getFirstPred(); 1627 while (NextNode) { 1628 N = NextNode; 1629 NextNode = N->getFirstPred(); 1630 ProgramPoint P = N->getLocation(); 1631 const LocationContext *LC = N->getLocationContext(); 1632 assert(!LCM[&PD.getActivePath()] || LCM[&PD.getActivePath()] == LC); 1633 LCM[&PD.getActivePath()] = LC; 1634 PathDiagnosticLocation &PrevLoc = PrevLocMap[LC->getCurrentStackFrame()]; 1635 1636 do { 1637 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1638 // For expressions, make sure we propagate the 1639 // interesting symbols correctly. 1640 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1641 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1642 N->getState().getPtr(), Ex, 1643 N->getLocationContext()); 1644 1645 PathDiagnosticLocation L = 1646 PathDiagnosticLocation(PS->getStmt(), SM, LC); 1647 addEdgeToPath(PD.getActivePath(), PrevLoc, L, LC); 1648 break; 1649 } 1650 1651 // Have we encountered an exit from a function call? 1652 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1653 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1654 // Propagate the interesting symbols accordingly. 1655 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1656 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1657 N->getState().getPtr(), Ex, 1658 N->getLocationContext()); 1659 } 1660 1661 // We are descending into a call (backwards). Construct 1662 // a new call piece to contain the path pieces for that call. 1663 PathDiagnosticCallPiece *C = 1664 PathDiagnosticCallPiece::construct(N, *CE, SM); 1665 1666 // Record the location context for this call piece. 1667 LCM[&C->path] = CE->getCalleeContext(); 1668 1669 // Add the edge to the return site. 1670 addEdgeToPath(PD.getActivePath(), PrevLoc, C->callReturn, LC); 1671 1672 // Make the contents of the call the active path for now. 1673 PD.pushActivePath(&C->path); 1674 CallStack.push_back(StackDiagPair(C, N)); 1675 break; 1676 } 1677 1678 // Have we encountered an entrance to a call? It may be 1679 // the case that we have not encountered a matching 1680 // call exit before this point. This means that the path 1681 // terminated within the call itself. 1682 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1683 // Add an edge to the start of the function. 1684 const Decl *D = CE->getCalleeContext()->getDecl(); 1685 addEdgeToPath(PD.getActivePath(), PrevLoc, 1686 PathDiagnosticLocation::createBegin(D, SM), LC); 1687 1688 // Did we visit an entire call? 1689 bool VisitedEntireCall = PD.isWithinCall(); 1690 PD.popActivePath(); 1691 1692 PathDiagnosticCallPiece *C; 1693 if (VisitedEntireCall) { 1694 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 1695 } else { 1696 const Decl *Caller = CE->getLocationContext()->getDecl(); 1697 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1698 LCM[&C->path] = CE->getCalleeContext(); 1699 } 1700 C->setCallee(*CE, SM); 1701 1702 if (!CallStack.empty()) { 1703 assert(CallStack.back().first == C); 1704 CallStack.pop_back(); 1705 } 1706 break; 1707 } 1708 1709 // Block edges. 1710 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1711 // Does this represent entering a call? If so, look at propagating 1712 // interesting symbols across call boundaries. 1713 if (NextNode) { 1714 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1715 const LocationContext *CalleeCtx = PDB.LC; 1716 if (CallerCtx != CalleeCtx) { 1717 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1718 N->getState().getPtr(), 1719 CalleeCtx, CallerCtx); 1720 } 1721 } 1722 1723 // Are we jumping to the head of a loop? Add a special diagnostic. 1724 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1725 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1726 const CompoundStmt *CS = NULL; 1727 1728 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1729 CS = dyn_cast<CompoundStmt>(FS->getBody()); 1730 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1731 CS = dyn_cast<CompoundStmt>(WS->getBody()); 1732 1733 PathDiagnosticEventPiece *p = 1734 new PathDiagnosticEventPiece(L, "Looping back to the head " 1735 "of the loop"); 1736 p->setPrunable(true); 1737 1738 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), LC); 1739 PD.getActivePath().push_front(p); 1740 EventCategory[p] = EC_LoopingBack; 1741 1742 if (CS) { 1743 addEdgeToPath(PD.getActivePath(), PrevLoc, 1744 PathDiagnosticLocation::createEndBrace(CS, SM), LC); 1745 } 1746 } 1747 1748 const CFGBlock *BSrc = BE->getSrc(); 1749 ParentMap &PM = PDB.getParentMap(); 1750 1751 if (const Stmt *Term = BSrc->getTerminator()) { 1752 // Are we jumping past the loop body without ever executing the 1753 // loop (because the condition was false)? 1754 if (isLoop(Term)) { 1755 const Stmt *TermCond = BSrc->getTerminatorCondition(); 1756 bool IsInLoopBody = 1757 isInLoopBody(PM, getStmtBeforeCond(PM, TermCond, N), Term); 1758 1759 const char *str = 0; 1760 enum EventCategorization EC = EC_None; 1761 1762 if (isJumpToFalseBranch(&*BE)) { 1763 if (!IsInLoopBody) { 1764 str = "Loop body executed 0 times"; 1765 } 1766 } 1767 else { 1768 str = "Entering loop body"; 1769 EC = EC_EnterLoop; 1770 } 1771 1772 if (str) { 1773 PathDiagnosticLocation L(TermCond, SM, PDB.LC); 1774 PathDiagnosticEventPiece *PE = 1775 new PathDiagnosticEventPiece(L, str); 1776 EventCategory[PE] = EC; 1777 PE->setPrunable(true); 1778 addEdgeToPath(PD.getActivePath(), PrevLoc, 1779 PE->getLocation(), LC); 1780 PD.getActivePath().push_front(PE); 1781 } 1782 } 1783 } 1784 break; 1785 } 1786 } while (0); 1787 1788 if (!NextNode) 1789 continue; 1790 1791 // Add pieces from custom visitors. 1792 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 1793 E = visitors.end(); 1794 I != E; ++I) { 1795 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *report)) { 1796 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), LC); 1797 PD.getActivePath().push_front(p); 1798 updateStackPiecesWithMessage(p, CallStack); 1799 } 1800 } 1801 } 1802 1803 if (report->isValid()) { 1804 // Prune redundant loop diagnostics. 1805 pruneLoopEvents(PD.getMutablePieces(), EventCategory); 1806 } 1807 1808 return report->isValid(); 1809} 1810 1811const Stmt *getLocStmt(PathDiagnosticLocation L) { 1812 if (!L.isValid()) 1813 return 0; 1814 return L.asStmt(); 1815} 1816 1817const Stmt *getStmtParent(const Stmt *S, ParentMap &PM) { 1818 if (!S) 1819 return 0; 1820 return PM.getParentIgnoreParens(S); 1821} 1822 1823static bool isConditionForTerminator(const Stmt *S, const Stmt *Cond) { 1824 // Note that we intentionally to do not handle || and && here. 1825 switch (S->getStmtClass()) { 1826 case Stmt::IfStmtClass: 1827 return cast<IfStmt>(S)->getCond() == Cond; 1828 case Stmt::ForStmtClass: 1829 return cast<ForStmt>(S)->getCond() == Cond; 1830 case Stmt::WhileStmtClass: 1831 return cast<WhileStmt>(S)->getCond() == Cond; 1832 case Stmt::DoStmtClass: 1833 return cast<DoStmt>(S)->getCond() == Cond; 1834 case Stmt::ChooseExprClass: 1835 return cast<ChooseExpr>(S)->getCond() == Cond; 1836 case Stmt::IndirectGotoStmtClass: 1837 return cast<IndirectGotoStmt>(S)->getTarget() == Cond; 1838 case Stmt::SwitchStmtClass: 1839 return cast<SwitchStmt>(S)->getCond() == Cond; 1840 case Stmt::BinaryConditionalOperatorClass: 1841 return cast<BinaryConditionalOperator>(S)->getCond() == Cond; 1842 case Stmt::ConditionalOperatorClass: 1843 return cast<ConditionalOperator>(S)->getCond() == Cond; 1844 case Stmt::ObjCForCollectionStmtClass: 1845 return cast<ObjCForCollectionStmt>(S)->getElement() == Cond; 1846 default: 1847 return false; 1848 } 1849} 1850 1851static bool isIncrementOrInitInForLoop(const Stmt *S, const Stmt *FL) { 1852 const ForStmt *FS = dyn_cast<ForStmt>(FL); 1853 if (!FS) 1854 return false; 1855 return FS->getInc() == S || FS->getInit() == S; 1856} 1857 1858typedef llvm::DenseSet<const PathDiagnosticCallPiece *> 1859 OptimizedCallsSet; 1860 1861static bool optimizeEdges(PathPieces &path, SourceManager &SM, 1862 OptimizedCallsSet &OCS, 1863 LocationContextMap &LCM) { 1864 bool hasChanges = false; 1865 const LocationContext *LC = LCM[&path]; 1866 assert(LC); 1867 bool isFirst = true; 1868 1869 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ) { 1870 bool wasFirst = isFirst; 1871 isFirst = false; 1872 1873 // Optimize subpaths. 1874 if (PathDiagnosticCallPiece *CallI = dyn_cast<PathDiagnosticCallPiece>(*I)){ 1875 // Record the fact that a call has been optimized so we only do the 1876 // effort once. 1877 if (!OCS.count(CallI)) { 1878 while (optimizeEdges(CallI->path, SM, OCS, LCM)) {} 1879 OCS.insert(CallI); 1880 } 1881 ++I; 1882 continue; 1883 } 1884 1885 // Pattern match the current piece and its successor. 1886 PathDiagnosticControlFlowPiece *PieceI = 1887 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 1888 1889 if (!PieceI) { 1890 ++I; 1891 continue; 1892 } 1893 1894 ParentMap &PM = LC->getParentMap(); 1895 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation()); 1896 const Stmt *s1End = getLocStmt(PieceI->getEndLocation()); 1897 const Stmt *level1 = getStmtParent(s1Start, PM); 1898 const Stmt *level2 = getStmtParent(s1End, PM); 1899 1900 if (wasFirst) { 1901 // If the first edge (in isolation) is just a transition from 1902 // an expression to a parent expression then eliminate that edge. 1903 if (level1 && level2 && level2 == PM.getParent(level1)) { 1904 path.erase(I); 1905 // Since we are erasing the current edge at the start of the 1906 // path, just return now so we start analyzing the start of the path 1907 // again. 1908 return true; 1909 } 1910 1911 // If the first edge (in isolation) is a transition from the 1912 // initialization or increment in a for loop then remove it. 1913 if (level1 && isIncrementOrInitInForLoop(s1Start, level1)) { 1914 path.erase(I); 1915 return true; 1916 } 1917 } 1918 1919 PathPieces::iterator NextI = I; ++NextI; 1920 if (NextI == E) 1921 break; 1922 1923 PathDiagnosticControlFlowPiece *PieceNextI = 1924 dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 1925 1926 if (!PieceNextI) { 1927 ++I; 1928 continue; 1929 } 1930 1931 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation()); 1932 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation()); 1933 const Stmt *level3 = getStmtParent(s2Start, PM); 1934 const Stmt *level4 = getStmtParent(s2End, PM); 1935 1936 // Rule I. 1937 // 1938 // If we have two consecutive control edges whose end/begin locations 1939 // are at the same level (e.g. statements or top-level expressions within 1940 // a compound statement, or siblings share a single ancestor expression), 1941 // then merge them if they have no interesting intermediate event. 1942 // 1943 // For example: 1944 // 1945 // (1.1 -> 1.2) -> (1.2 -> 1.3) becomes (1.1 -> 1.3) because the common 1946 // parent is '1'. Here 'x.y.z' represents the hierarchy of statements. 1947 // 1948 // NOTE: this will be limited later in cases where we add barriers 1949 // to prevent this optimization. 1950 // 1951 if (level1 && level1 == level2 && level1 == level3 && level1 == level4) { 1952 PieceI->setEndLocation(PieceNextI->getEndLocation()); 1953 path.erase(NextI); 1954 hasChanges = true; 1955 continue; 1956 } 1957 1958 // Rule II. 1959 // 1960 // Eliminate edges between subexpressions and parent expressions 1961 // when the subexpression is consumed. 1962 // 1963 // NOTE: this will be limited later in cases where we add barriers 1964 // to prevent this optimization. 1965 // 1966 if (s1End && s1End == s2Start && level2) { 1967 if (isIncrementOrInitInForLoop(s1End, level2) || 1968 (isa<Expr>(s1End) && PM.isConsumedExpr(cast<Expr>(s1End)) && 1969 !isConditionForTerminator(level2, s1End))) 1970 { 1971 PieceI->setEndLocation(PieceNextI->getEndLocation()); 1972 path.erase(NextI); 1973 hasChanges = true; 1974 continue; 1975 } 1976 } 1977 1978 // No changes at this index? Move to the next one. 1979 ++I; 1980 } 1981 1982 // No changes. 1983 return hasChanges; 1984} 1985 1986//===----------------------------------------------------------------------===// 1987// Methods for BugType and subclasses. 1988//===----------------------------------------------------------------------===// 1989BugType::~BugType() { } 1990 1991void BugType::FlushReports(BugReporter &BR) {} 1992 1993void BuiltinBug::anchor() {} 1994 1995//===----------------------------------------------------------------------===// 1996// Methods for BugReport and subclasses. 1997//===----------------------------------------------------------------------===// 1998 1999void BugReport::NodeResolver::anchor() {} 2000 2001void BugReport::addVisitor(BugReporterVisitor* visitor) { 2002 if (!visitor) 2003 return; 2004 2005 llvm::FoldingSetNodeID ID; 2006 visitor->Profile(ID); 2007 void *InsertPos; 2008 2009 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) { 2010 delete visitor; 2011 return; 2012 } 2013 2014 CallbacksSet.InsertNode(visitor, InsertPos); 2015 Callbacks.push_back(visitor); 2016 ++ConfigurationChangeToken; 2017} 2018 2019BugReport::~BugReport() { 2020 for (visitor_iterator I = visitor_begin(), E = visitor_end(); I != E; ++I) { 2021 delete *I; 2022 } 2023 while (!interestingSymbols.empty()) { 2024 popInterestingSymbolsAndRegions(); 2025 } 2026} 2027 2028const Decl *BugReport::getDeclWithIssue() const { 2029 if (DeclWithIssue) 2030 return DeclWithIssue; 2031 2032 const ExplodedNode *N = getErrorNode(); 2033 if (!N) 2034 return 0; 2035 2036 const LocationContext *LC = N->getLocationContext(); 2037 return LC->getCurrentStackFrame()->getDecl(); 2038} 2039 2040void BugReport::Profile(llvm::FoldingSetNodeID& hash) const { 2041 hash.AddPointer(&BT); 2042 hash.AddString(Description); 2043 PathDiagnosticLocation UL = getUniqueingLocation(); 2044 if (UL.isValid()) { 2045 UL.Profile(hash); 2046 } else if (Location.isValid()) { 2047 Location.Profile(hash); 2048 } else { 2049 assert(ErrorNode); 2050 hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode)); 2051 } 2052 2053 for (SmallVectorImpl<SourceRange>::const_iterator I = 2054 Ranges.begin(), E = Ranges.end(); I != E; ++I) { 2055 const SourceRange range = *I; 2056 if (!range.isValid()) 2057 continue; 2058 hash.AddInteger(range.getBegin().getRawEncoding()); 2059 hash.AddInteger(range.getEnd().getRawEncoding()); 2060 } 2061} 2062 2063void BugReport::markInteresting(SymbolRef sym) { 2064 if (!sym) 2065 return; 2066 2067 // If the symbol wasn't already in our set, note a configuration change. 2068 if (getInterestingSymbols().insert(sym).second) 2069 ++ConfigurationChangeToken; 2070 2071 if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym)) 2072 getInterestingRegions().insert(meta->getRegion()); 2073} 2074 2075void BugReport::markInteresting(const MemRegion *R) { 2076 if (!R) 2077 return; 2078 2079 // If the base region wasn't already in our set, note a configuration change. 2080 R = R->getBaseRegion(); 2081 if (getInterestingRegions().insert(R).second) 2082 ++ConfigurationChangeToken; 2083 2084 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2085 getInterestingSymbols().insert(SR->getSymbol()); 2086} 2087 2088void BugReport::markInteresting(SVal V) { 2089 markInteresting(V.getAsRegion()); 2090 markInteresting(V.getAsSymbol()); 2091} 2092 2093void BugReport::markInteresting(const LocationContext *LC) { 2094 if (!LC) 2095 return; 2096 InterestingLocationContexts.insert(LC); 2097} 2098 2099bool BugReport::isInteresting(SVal V) { 2100 return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol()); 2101} 2102 2103bool BugReport::isInteresting(SymbolRef sym) { 2104 if (!sym) 2105 return false; 2106 // We don't currently consider metadata symbols to be interesting 2107 // even if we know their region is interesting. Is that correct behavior? 2108 return getInterestingSymbols().count(sym); 2109} 2110 2111bool BugReport::isInteresting(const MemRegion *R) { 2112 if (!R) 2113 return false; 2114 R = R->getBaseRegion(); 2115 bool b = getInterestingRegions().count(R); 2116 if (b) 2117 return true; 2118 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2119 return getInterestingSymbols().count(SR->getSymbol()); 2120 return false; 2121} 2122 2123bool BugReport::isInteresting(const LocationContext *LC) { 2124 if (!LC) 2125 return false; 2126 return InterestingLocationContexts.count(LC); 2127} 2128 2129void BugReport::lazyInitializeInterestingSets() { 2130 if (interestingSymbols.empty()) { 2131 interestingSymbols.push_back(new Symbols()); 2132 interestingRegions.push_back(new Regions()); 2133 } 2134} 2135 2136BugReport::Symbols &BugReport::getInterestingSymbols() { 2137 lazyInitializeInterestingSets(); 2138 return *interestingSymbols.back(); 2139} 2140 2141BugReport::Regions &BugReport::getInterestingRegions() { 2142 lazyInitializeInterestingSets(); 2143 return *interestingRegions.back(); 2144} 2145 2146void BugReport::pushInterestingSymbolsAndRegions() { 2147 interestingSymbols.push_back(new Symbols(getInterestingSymbols())); 2148 interestingRegions.push_back(new Regions(getInterestingRegions())); 2149} 2150 2151void BugReport::popInterestingSymbolsAndRegions() { 2152 delete interestingSymbols.back(); 2153 interestingSymbols.pop_back(); 2154 delete interestingRegions.back(); 2155 interestingRegions.pop_back(); 2156} 2157 2158const Stmt *BugReport::getStmt() const { 2159 if (!ErrorNode) 2160 return 0; 2161 2162 ProgramPoint ProgP = ErrorNode->getLocation(); 2163 const Stmt *S = NULL; 2164 2165 if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) { 2166 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit(); 2167 if (BE->getBlock() == &Exit) 2168 S = GetPreviousStmt(ErrorNode); 2169 } 2170 if (!S) 2171 S = PathDiagnosticLocation::getStmt(ErrorNode); 2172 2173 return S; 2174} 2175 2176std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator> 2177BugReport::getRanges() { 2178 // If no custom ranges, add the range of the statement corresponding to 2179 // the error node. 2180 if (Ranges.empty()) { 2181 if (const Expr *E = dyn_cast_or_null<Expr>(getStmt())) 2182 addRange(E->getSourceRange()); 2183 else 2184 return std::make_pair(ranges_iterator(), ranges_iterator()); 2185 } 2186 2187 // User-specified absence of range info. 2188 if (Ranges.size() == 1 && !Ranges.begin()->isValid()) 2189 return std::make_pair(ranges_iterator(), ranges_iterator()); 2190 2191 return std::make_pair(Ranges.begin(), Ranges.end()); 2192} 2193 2194PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const { 2195 if (ErrorNode) { 2196 assert(!Location.isValid() && 2197 "Either Location or ErrorNode should be specified but not both."); 2198 return PathDiagnosticLocation::createEndOfPath(ErrorNode, SM); 2199 } else { 2200 assert(Location.isValid()); 2201 return Location; 2202 } 2203 2204 return PathDiagnosticLocation(); 2205} 2206 2207//===----------------------------------------------------------------------===// 2208// Methods for BugReporter and subclasses. 2209//===----------------------------------------------------------------------===// 2210 2211BugReportEquivClass::~BugReportEquivClass() { } 2212GRBugReporter::~GRBugReporter() { } 2213BugReporterData::~BugReporterData() {} 2214 2215ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); } 2216 2217ProgramStateManager& 2218GRBugReporter::getStateManager() { return Eng.getStateManager(); } 2219 2220BugReporter::~BugReporter() { 2221 FlushReports(); 2222 2223 // Free the bug reports we are tracking. 2224 typedef std::vector<BugReportEquivClass *> ContTy; 2225 for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end(); 2226 I != E; ++I) { 2227 delete *I; 2228 } 2229} 2230 2231void BugReporter::FlushReports() { 2232 if (BugTypes.isEmpty()) 2233 return; 2234 2235 // First flush the warnings for each BugType. This may end up creating new 2236 // warnings and new BugTypes. 2237 // FIXME: Only NSErrorChecker needs BugType's FlushReports. 2238 // Turn NSErrorChecker into a proper checker and remove this. 2239 SmallVector<const BugType*, 16> bugTypes; 2240 for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I) 2241 bugTypes.push_back(*I); 2242 for (SmallVector<const BugType*, 16>::iterator 2243 I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I) 2244 const_cast<BugType*>(*I)->FlushReports(*this); 2245 2246 // We need to flush reports in deterministic order to ensure the order 2247 // of the reports is consistent between runs. 2248 typedef std::vector<BugReportEquivClass *> ContVecTy; 2249 for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end(); 2250 EI != EE; ++EI){ 2251 BugReportEquivClass& EQ = **EI; 2252 FlushReport(EQ); 2253 } 2254 2255 // BugReporter owns and deletes only BugTypes created implicitly through 2256 // EmitBasicReport. 2257 // FIXME: There are leaks from checkers that assume that the BugTypes they 2258 // create will be destroyed by the BugReporter. 2259 for (llvm::StringMap<BugType*>::iterator 2260 I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I) 2261 delete I->second; 2262 2263 // Remove all references to the BugType objects. 2264 BugTypes = F.getEmptySet(); 2265} 2266 2267//===----------------------------------------------------------------------===// 2268// PathDiagnostics generation. 2269//===----------------------------------------------------------------------===// 2270 2271namespace { 2272/// A wrapper around a report graph, which contains only a single path, and its 2273/// node maps. 2274class ReportGraph { 2275public: 2276 InterExplodedGraphMap BackMap; 2277 OwningPtr<ExplodedGraph> Graph; 2278 const ExplodedNode *ErrorNode; 2279 size_t Index; 2280}; 2281 2282/// A wrapper around a trimmed graph and its node maps. 2283class TrimmedGraph { 2284 InterExplodedGraphMap InverseMap; 2285 2286 typedef llvm::DenseMap<const ExplodedNode *, unsigned> PriorityMapTy; 2287 PriorityMapTy PriorityMap; 2288 2289 typedef std::pair<const ExplodedNode *, size_t> NodeIndexPair; 2290 SmallVector<NodeIndexPair, 32> ReportNodes; 2291 2292 OwningPtr<ExplodedGraph> G; 2293 2294 /// A helper class for sorting ExplodedNodes by priority. 2295 template <bool Descending> 2296 class PriorityCompare { 2297 const PriorityMapTy &PriorityMap; 2298 2299 public: 2300 PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {} 2301 2302 bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const { 2303 PriorityMapTy::const_iterator LI = PriorityMap.find(LHS); 2304 PriorityMapTy::const_iterator RI = PriorityMap.find(RHS); 2305 PriorityMapTy::const_iterator E = PriorityMap.end(); 2306 2307 if (LI == E) 2308 return Descending; 2309 if (RI == E) 2310 return !Descending; 2311 2312 return Descending ? LI->second > RI->second 2313 : LI->second < RI->second; 2314 } 2315 2316 bool operator()(const NodeIndexPair &LHS, const NodeIndexPair &RHS) const { 2317 return (*this)(LHS.first, RHS.first); 2318 } 2319 }; 2320 2321public: 2322 TrimmedGraph(const ExplodedGraph *OriginalGraph, 2323 ArrayRef<const ExplodedNode *> Nodes); 2324 2325 bool popNextReportGraph(ReportGraph &GraphWrapper); 2326}; 2327} 2328 2329TrimmedGraph::TrimmedGraph(const ExplodedGraph *OriginalGraph, 2330 ArrayRef<const ExplodedNode *> Nodes) { 2331 // The trimmed graph is created in the body of the constructor to ensure 2332 // that the DenseMaps have been initialized already. 2333 InterExplodedGraphMap ForwardMap; 2334 G.reset(OriginalGraph->trim(Nodes, &ForwardMap, &InverseMap)); 2335 2336 // Find the (first) error node in the trimmed graph. We just need to consult 2337 // the node map which maps from nodes in the original graph to nodes 2338 // in the new graph. 2339 llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes; 2340 2341 for (unsigned i = 0, count = Nodes.size(); i < count; ++i) { 2342 if (const ExplodedNode *NewNode = ForwardMap.lookup(Nodes[i])) { 2343 ReportNodes.push_back(std::make_pair(NewNode, i)); 2344 RemainingNodes.insert(NewNode); 2345 } 2346 } 2347 2348 assert(!RemainingNodes.empty() && "No error node found in the trimmed graph"); 2349 2350 // Perform a forward BFS to find all the shortest paths. 2351 std::queue<const ExplodedNode *> WS; 2352 2353 assert(G->num_roots() == 1); 2354 WS.push(*G->roots_begin()); 2355 unsigned Priority = 0; 2356 2357 while (!WS.empty()) { 2358 const ExplodedNode *Node = WS.front(); 2359 WS.pop(); 2360 2361 PriorityMapTy::iterator PriorityEntry; 2362 bool IsNew; 2363 llvm::tie(PriorityEntry, IsNew) = 2364 PriorityMap.insert(std::make_pair(Node, Priority)); 2365 ++Priority; 2366 2367 if (!IsNew) { 2368 assert(PriorityEntry->second <= Priority); 2369 continue; 2370 } 2371 2372 if (RemainingNodes.erase(Node)) 2373 if (RemainingNodes.empty()) 2374 break; 2375 2376 for (ExplodedNode::const_pred_iterator I = Node->succ_begin(), 2377 E = Node->succ_end(); 2378 I != E; ++I) 2379 WS.push(*I); 2380 } 2381 2382 // Sort the error paths from longest to shortest. 2383 std::sort(ReportNodes.begin(), ReportNodes.end(), 2384 PriorityCompare<true>(PriorityMap)); 2385} 2386 2387bool TrimmedGraph::popNextReportGraph(ReportGraph &GraphWrapper) { 2388 if (ReportNodes.empty()) 2389 return false; 2390 2391 const ExplodedNode *OrigN; 2392 llvm::tie(OrigN, GraphWrapper.Index) = ReportNodes.pop_back_val(); 2393 assert(PriorityMap.find(OrigN) != PriorityMap.end() && 2394 "error node not accessible from root"); 2395 2396 // Create a new graph with a single path. This is the graph 2397 // that will be returned to the caller. 2398 ExplodedGraph *GNew = new ExplodedGraph(); 2399 GraphWrapper.Graph.reset(GNew); 2400 GraphWrapper.BackMap.clear(); 2401 2402 // Now walk from the error node up the BFS path, always taking the 2403 // predeccessor with the lowest number. 2404 ExplodedNode *Succ = 0; 2405 while (true) { 2406 // Create the equivalent node in the new graph with the same state 2407 // and location. 2408 ExplodedNode *NewN = GNew->getNode(OrigN->getLocation(), OrigN->getState(), 2409 OrigN->isSink()); 2410 2411 // Store the mapping to the original node. 2412 InterExplodedGraphMap::const_iterator IMitr = InverseMap.find(OrigN); 2413 assert(IMitr != InverseMap.end() && "No mapping to original node."); 2414 GraphWrapper.BackMap[NewN] = IMitr->second; 2415 2416 // Link up the new node with the previous node. 2417 if (Succ) 2418 Succ->addPredecessor(NewN, *GNew); 2419 else 2420 GraphWrapper.ErrorNode = NewN; 2421 2422 Succ = NewN; 2423 2424 // Are we at the final node? 2425 if (OrigN->pred_empty()) { 2426 GNew->addRoot(NewN); 2427 break; 2428 } 2429 2430 // Find the next predeccessor node. We choose the node that is marked 2431 // with the lowest BFS number. 2432 OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(), 2433 PriorityCompare<false>(PriorityMap)); 2434 } 2435 2436 return true; 2437} 2438 2439 2440/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object 2441/// and collapses PathDiagosticPieces that are expanded by macros. 2442static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) { 2443 typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>, 2444 SourceLocation> > MacroStackTy; 2445 2446 typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> > 2447 PiecesTy; 2448 2449 MacroStackTy MacroStack; 2450 PiecesTy Pieces; 2451 2452 for (PathPieces::const_iterator I = path.begin(), E = path.end(); 2453 I!=E; ++I) { 2454 2455 PathDiagnosticPiece *piece = I->getPtr(); 2456 2457 // Recursively compact calls. 2458 if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){ 2459 CompactPathDiagnostic(call->path, SM); 2460 } 2461 2462 // Get the location of the PathDiagnosticPiece. 2463 const FullSourceLoc Loc = piece->getLocation().asLocation(); 2464 2465 // Determine the instantiation location, which is the location we group 2466 // related PathDiagnosticPieces. 2467 SourceLocation InstantiationLoc = Loc.isMacroID() ? 2468 SM.getExpansionLoc(Loc) : 2469 SourceLocation(); 2470 2471 if (Loc.isFileID()) { 2472 MacroStack.clear(); 2473 Pieces.push_back(piece); 2474 continue; 2475 } 2476 2477 assert(Loc.isMacroID()); 2478 2479 // Is the PathDiagnosticPiece within the same macro group? 2480 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) { 2481 MacroStack.back().first->subPieces.push_back(piece); 2482 continue; 2483 } 2484 2485 // We aren't in the same group. Are we descending into a new macro 2486 // or are part of an old one? 2487 IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup; 2488 2489 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ? 2490 SM.getExpansionLoc(Loc) : 2491 SourceLocation(); 2492 2493 // Walk the entire macro stack. 2494 while (!MacroStack.empty()) { 2495 if (InstantiationLoc == MacroStack.back().second) { 2496 MacroGroup = MacroStack.back().first; 2497 break; 2498 } 2499 2500 if (ParentInstantiationLoc == MacroStack.back().second) { 2501 MacroGroup = MacroStack.back().first; 2502 break; 2503 } 2504 2505 MacroStack.pop_back(); 2506 } 2507 2508 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) { 2509 // Create a new macro group and add it to the stack. 2510 PathDiagnosticMacroPiece *NewGroup = 2511 new PathDiagnosticMacroPiece( 2512 PathDiagnosticLocation::createSingleLocation(piece->getLocation())); 2513 2514 if (MacroGroup) 2515 MacroGroup->subPieces.push_back(NewGroup); 2516 else { 2517 assert(InstantiationLoc.isFileID()); 2518 Pieces.push_back(NewGroup); 2519 } 2520 2521 MacroGroup = NewGroup; 2522 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc)); 2523 } 2524 2525 // Finally, add the PathDiagnosticPiece to the group. 2526 MacroGroup->subPieces.push_back(piece); 2527 } 2528 2529 // Now take the pieces and construct a new PathDiagnostic. 2530 path.clear(); 2531 2532 for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I) 2533 path.push_back(*I); 2534} 2535 2536bool GRBugReporter::generatePathDiagnostic(PathDiagnostic& PD, 2537 PathDiagnosticConsumer &PC, 2538 ArrayRef<BugReport *> &bugReports) { 2539 assert(!bugReports.empty()); 2540 2541 bool HasValid = false; 2542 bool HasInvalid = false; 2543 SmallVector<const ExplodedNode *, 32> errorNodes; 2544 for (ArrayRef<BugReport*>::iterator I = bugReports.begin(), 2545 E = bugReports.end(); I != E; ++I) { 2546 if ((*I)->isValid()) { 2547 HasValid = true; 2548 errorNodes.push_back((*I)->getErrorNode()); 2549 } else { 2550 // Keep the errorNodes list in sync with the bugReports list. 2551 HasInvalid = true; 2552 errorNodes.push_back(0); 2553 } 2554 } 2555 2556 // If all the reports have been marked invalid by a previous path generation, 2557 // we're done. 2558 if (!HasValid) 2559 return false; 2560 2561 typedef PathDiagnosticConsumer::PathGenerationScheme PathGenerationScheme; 2562 PathGenerationScheme ActiveScheme = PC.getGenerationScheme(); 2563 2564 if (ActiveScheme == PathDiagnosticConsumer::Extensive) { 2565 AnalyzerOptions &options = getEngine().getAnalysisManager().options; 2566 if (options.getBooleanOption("path-diagnostics-alternate", false)) { 2567 ActiveScheme = PathDiagnosticConsumer::AlternateExtensive; 2568 } 2569 } 2570 2571 TrimmedGraph TrimG(&getGraph(), errorNodes); 2572 ReportGraph ErrorGraph; 2573 2574 while (TrimG.popNextReportGraph(ErrorGraph)) { 2575 // Find the BugReport with the original location. 2576 assert(ErrorGraph.Index < bugReports.size()); 2577 BugReport *R = bugReports[ErrorGraph.Index]; 2578 assert(R && "No original report found for sliced graph."); 2579 assert(R->isValid() && "Report selected by trimmed graph marked invalid."); 2580 2581 // Start building the path diagnostic... 2582 PathDiagnosticBuilder PDB(*this, R, ErrorGraph.BackMap, &PC); 2583 const ExplodedNode *N = ErrorGraph.ErrorNode; 2584 2585 // Register additional node visitors. 2586 R->addVisitor(new NilReceiverBRVisitor()); 2587 R->addVisitor(new ConditionBRVisitor()); 2588 R->addVisitor(new LikelyFalsePositiveSuppressionBRVisitor()); 2589 2590 BugReport::VisitorList visitors; 2591 unsigned origReportConfigToken, finalReportConfigToken; 2592 LocationContextMap LCM; 2593 2594 // While generating diagnostics, it's possible the visitors will decide 2595 // new symbols and regions are interesting, or add other visitors based on 2596 // the information they find. If they do, we need to regenerate the path 2597 // based on our new report configuration. 2598 do { 2599 // Get a clean copy of all the visitors. 2600 for (BugReport::visitor_iterator I = R->visitor_begin(), 2601 E = R->visitor_end(); I != E; ++I) 2602 visitors.push_back((*I)->clone()); 2603 2604 // Clear out the active path from any previous work. 2605 PD.resetPath(); 2606 origReportConfigToken = R->getConfigurationChangeToken(); 2607 2608 // Generate the very last diagnostic piece - the piece is visible before 2609 // the trace is expanded. 2610 PathDiagnosticPiece *LastPiece = 0; 2611 for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end(); 2612 I != E; ++I) { 2613 if (PathDiagnosticPiece *Piece = (*I)->getEndPath(PDB, N, *R)) { 2614 assert (!LastPiece && 2615 "There can only be one final piece in a diagnostic."); 2616 LastPiece = Piece; 2617 } 2618 } 2619 2620 if (ActiveScheme != PathDiagnosticConsumer::None) { 2621 if (!LastPiece) 2622 LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R); 2623 assert(LastPiece); 2624 PD.setEndOfPath(LastPiece); 2625 } 2626 2627 // Make sure we get a clean location context map so we don't 2628 // hold onto old mappings. 2629 LCM.clear(); 2630 2631 switch (ActiveScheme) { 2632 case PathDiagnosticConsumer::AlternateExtensive: 2633 GenerateAlternateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 2634 break; 2635 case PathDiagnosticConsumer::Extensive: 2636 GenerateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 2637 break; 2638 case PathDiagnosticConsumer::Minimal: 2639 GenerateMinimalPathDiagnostic(PD, PDB, N, LCM, visitors); 2640 break; 2641 case PathDiagnosticConsumer::None: 2642 GenerateVisitorsOnlyPathDiagnostic(PD, PDB, N, visitors); 2643 break; 2644 } 2645 2646 // Clean up the visitors we used. 2647 llvm::DeleteContainerPointers(visitors); 2648 2649 // Did anything change while generating this path? 2650 finalReportConfigToken = R->getConfigurationChangeToken(); 2651 } while (finalReportConfigToken != origReportConfigToken); 2652 2653 if (!R->isValid()) 2654 continue; 2655 2656 // Finally, prune the diagnostic path of uninteresting stuff. 2657 if (!PD.path.empty()) { 2658 // Remove messages that are basically the same. 2659 removeRedundantMsgs(PD.getMutablePieces()); 2660 2661 if (R->shouldPrunePath() && 2662 getEngine().getAnalysisManager().options.shouldPrunePaths()) { 2663 bool stillHasNotes = removeUnneededCalls(PD.getMutablePieces(), R, LCM); 2664 assert(stillHasNotes); 2665 (void)stillHasNotes; 2666 } 2667 2668 adjustCallLocations(PD.getMutablePieces()); 2669 2670 if (ActiveScheme == PathDiagnosticConsumer::AlternateExtensive) { 2671 OptimizedCallsSet OCS; 2672 while (optimizeEdges(PD.getMutablePieces(), getSourceManager(), 2673 OCS, LCM)) {} 2674 } 2675 } 2676 2677 // We found a report and didn't suppress it. 2678 return true; 2679 } 2680 2681 // We suppressed all the reports in this equivalence class. 2682 assert(!HasInvalid && "Inconsistent suppression"); 2683 (void)HasInvalid; 2684 return false; 2685} 2686 2687void BugReporter::Register(BugType *BT) { 2688 BugTypes = F.add(BugTypes, BT); 2689} 2690 2691void BugReporter::emitReport(BugReport* R) { 2692 // Compute the bug report's hash to determine its equivalence class. 2693 llvm::FoldingSetNodeID ID; 2694 R->Profile(ID); 2695 2696 // Lookup the equivance class. If there isn't one, create it. 2697 BugType& BT = R->getBugType(); 2698 Register(&BT); 2699 void *InsertPos; 2700 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos); 2701 2702 if (!EQ) { 2703 EQ = new BugReportEquivClass(R); 2704 EQClasses.InsertNode(EQ, InsertPos); 2705 EQClassesVector.push_back(EQ); 2706 } 2707 else 2708 EQ->AddReport(R); 2709} 2710 2711 2712//===----------------------------------------------------------------------===// 2713// Emitting reports in equivalence classes. 2714//===----------------------------------------------------------------------===// 2715 2716namespace { 2717struct FRIEC_WLItem { 2718 const ExplodedNode *N; 2719 ExplodedNode::const_succ_iterator I, E; 2720 2721 FRIEC_WLItem(const ExplodedNode *n) 2722 : N(n), I(N->succ_begin()), E(N->succ_end()) {} 2723}; 2724} 2725 2726static BugReport * 2727FindReportInEquivalenceClass(BugReportEquivClass& EQ, 2728 SmallVectorImpl<BugReport*> &bugReports) { 2729 2730 BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end(); 2731 assert(I != E); 2732 BugType& BT = I->getBugType(); 2733 2734 // If we don't need to suppress any of the nodes because they are 2735 // post-dominated by a sink, simply add all the nodes in the equivalence class 2736 // to 'Nodes'. Any of the reports will serve as a "representative" report. 2737 if (!BT.isSuppressOnSink()) { 2738 BugReport *R = I; 2739 for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) { 2740 const ExplodedNode *N = I->getErrorNode(); 2741 if (N) { 2742 R = I; 2743 bugReports.push_back(R); 2744 } 2745 } 2746 return R; 2747 } 2748 2749 // For bug reports that should be suppressed when all paths are post-dominated 2750 // by a sink node, iterate through the reports in the equivalence class 2751 // until we find one that isn't post-dominated (if one exists). We use a 2752 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write 2753 // this as a recursive function, but we don't want to risk blowing out the 2754 // stack for very long paths. 2755 BugReport *exampleReport = 0; 2756 2757 for (; I != E; ++I) { 2758 const ExplodedNode *errorNode = I->getErrorNode(); 2759 2760 if (!errorNode) 2761 continue; 2762 if (errorNode->isSink()) { 2763 llvm_unreachable( 2764 "BugType::isSuppressSink() should not be 'true' for sink end nodes"); 2765 } 2766 // No successors? By definition this nodes isn't post-dominated by a sink. 2767 if (errorNode->succ_empty()) { 2768 bugReports.push_back(I); 2769 if (!exampleReport) 2770 exampleReport = I; 2771 continue; 2772 } 2773 2774 // At this point we know that 'N' is not a sink and it has at least one 2775 // successor. Use a DFS worklist to find a non-sink end-of-path node. 2776 typedef FRIEC_WLItem WLItem; 2777 typedef SmallVector<WLItem, 10> DFSWorkList; 2778 llvm::DenseMap<const ExplodedNode *, unsigned> Visited; 2779 2780 DFSWorkList WL; 2781 WL.push_back(errorNode); 2782 Visited[errorNode] = 1; 2783 2784 while (!WL.empty()) { 2785 WLItem &WI = WL.back(); 2786 assert(!WI.N->succ_empty()); 2787 2788 for (; WI.I != WI.E; ++WI.I) { 2789 const ExplodedNode *Succ = *WI.I; 2790 // End-of-path node? 2791 if (Succ->succ_empty()) { 2792 // If we found an end-of-path node that is not a sink. 2793 if (!Succ->isSink()) { 2794 bugReports.push_back(I); 2795 if (!exampleReport) 2796 exampleReport = I; 2797 WL.clear(); 2798 break; 2799 } 2800 // Found a sink? Continue on to the next successor. 2801 continue; 2802 } 2803 // Mark the successor as visited. If it hasn't been explored, 2804 // enqueue it to the DFS worklist. 2805 unsigned &mark = Visited[Succ]; 2806 if (!mark) { 2807 mark = 1; 2808 WL.push_back(Succ); 2809 break; 2810 } 2811 } 2812 2813 // The worklist may have been cleared at this point. First 2814 // check if it is empty before checking the last item. 2815 if (!WL.empty() && &WL.back() == &WI) 2816 WL.pop_back(); 2817 } 2818 } 2819 2820 // ExampleReport will be NULL if all the nodes in the equivalence class 2821 // were post-dominated by sinks. 2822 return exampleReport; 2823} 2824 2825void BugReporter::FlushReport(BugReportEquivClass& EQ) { 2826 SmallVector<BugReport*, 10> bugReports; 2827 BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports); 2828 if (exampleReport) { 2829 const PathDiagnosticConsumers &C = getPathDiagnosticConsumers(); 2830 for (PathDiagnosticConsumers::const_iterator I=C.begin(), 2831 E=C.end(); I != E; ++I) { 2832 FlushReport(exampleReport, **I, bugReports); 2833 } 2834 } 2835} 2836 2837void BugReporter::FlushReport(BugReport *exampleReport, 2838 PathDiagnosticConsumer &PD, 2839 ArrayRef<BugReport*> bugReports) { 2840 2841 // FIXME: Make sure we use the 'R' for the path that was actually used. 2842 // Probably doesn't make a difference in practice. 2843 BugType& BT = exampleReport->getBugType(); 2844 2845 OwningPtr<PathDiagnostic> 2846 D(new PathDiagnostic(exampleReport->getDeclWithIssue(), 2847 exampleReport->getBugType().getName(), 2848 exampleReport->getDescription(), 2849 exampleReport->getShortDescription(/*Fallback=*/false), 2850 BT.getCategory(), 2851 exampleReport->getUniqueingLocation(), 2852 exampleReport->getUniqueingDecl())); 2853 2854 MaxBugClassSize = std::max(bugReports.size(), 2855 static_cast<size_t>(MaxBugClassSize)); 2856 2857 // Generate the full path diagnostic, using the generation scheme 2858 // specified by the PathDiagnosticConsumer. Note that we have to generate 2859 // path diagnostics even for consumers which do not support paths, because 2860 // the BugReporterVisitors may mark this bug as a false positive. 2861 if (!bugReports.empty()) 2862 if (!generatePathDiagnostic(*D.get(), PD, bugReports)) 2863 return; 2864 2865 MaxValidBugClassSize = std::max(bugReports.size(), 2866 static_cast<size_t>(MaxValidBugClassSize)); 2867 2868 // If the path is empty, generate a single step path with the location 2869 // of the issue. 2870 if (D->path.empty()) { 2871 PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager()); 2872 PathDiagnosticPiece *piece = 2873 new PathDiagnosticEventPiece(L, exampleReport->getDescription()); 2874 BugReport::ranges_iterator Beg, End; 2875 llvm::tie(Beg, End) = exampleReport->getRanges(); 2876 for ( ; Beg != End; ++Beg) 2877 piece->addRange(*Beg); 2878 D->setEndOfPath(piece); 2879 } 2880 2881 // Get the meta data. 2882 const BugReport::ExtraTextList &Meta = exampleReport->getExtraText(); 2883 for (BugReport::ExtraTextList::const_iterator i = Meta.begin(), 2884 e = Meta.end(); i != e; ++i) { 2885 D->addMeta(*i); 2886 } 2887 2888 PD.HandlePathDiagnostic(D.take()); 2889} 2890 2891void BugReporter::EmitBasicReport(const Decl *DeclWithIssue, 2892 StringRef name, 2893 StringRef category, 2894 StringRef str, PathDiagnosticLocation Loc, 2895 SourceRange* RBeg, unsigned NumRanges) { 2896 2897 // 'BT' is owned by BugReporter. 2898 BugType *BT = getBugTypeForName(name, category); 2899 BugReport *R = new BugReport(*BT, str, Loc); 2900 R->setDeclWithIssue(DeclWithIssue); 2901 for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg); 2902 emitReport(R); 2903} 2904 2905BugType *BugReporter::getBugTypeForName(StringRef name, 2906 StringRef category) { 2907 SmallString<136> fullDesc; 2908 llvm::raw_svector_ostream(fullDesc) << name << ":" << category; 2909 llvm::StringMapEntry<BugType *> & 2910 entry = StrBugTypes.GetOrCreateValue(fullDesc); 2911 BugType *BT = entry.getValue(); 2912 if (!BT) { 2913 BT = new BugType(name, category); 2914 entry.setValue(BT); 2915 } 2916 return BT; 2917} 2918