BugReporter.cpp revision afde200cdae9731aa5826c6178eae9e7fef74475
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 1569static bool 1570GenerateAlternateExtensivePathDiagnostic(PathDiagnostic& PD, 1571 PathDiagnosticBuilder &PDB, 1572 const ExplodedNode *N, 1573 LocationContextMap &LCM, 1574 ArrayRef<BugReporterVisitor *> visitors) { 1575 1576 BugReport *report = PDB.getBugReport(); 1577 const SourceManager& SM = PDB.getSourceManager(); 1578 StackDiagVector CallStack; 1579 InterestingExprs IE; 1580 1581 // Record the last location for a given visited stack frame. 1582 llvm::DenseMap<const StackFrameContext *, PathDiagnosticLocation> 1583 PrevLocMap; 1584 1585 const ExplodedNode *NextNode = N->getFirstPred(); 1586 while (NextNode) { 1587 N = NextNode; 1588 NextNode = N->getFirstPred(); 1589 ProgramPoint P = N->getLocation(); 1590 1591 do { 1592 // Have we encountered an entrance to a call? It may be 1593 // the case that we have not encountered a matching 1594 // call exit before this point. This means that the path 1595 // terminated within the call itself. 1596 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1597 // Add an edge to the start of the function. 1598 const StackFrameContext *CalleeLC = CE->getCalleeContext(); 1599 PathDiagnosticLocation &PrevLocCallee = PrevLocMap[CalleeLC]; 1600 const Decl *D = CalleeLC->getDecl(); 1601 addEdgeToPath(PD.getActivePath(), PrevLocCallee, 1602 PathDiagnosticLocation::createBegin(D, SM), 1603 CalleeLC); 1604 1605 // Did we visit an entire call? 1606 bool VisitedEntireCall = PD.isWithinCall(); 1607 PD.popActivePath(); 1608 1609 PathDiagnosticCallPiece *C; 1610 if (VisitedEntireCall) { 1611 PathDiagnosticPiece *P = PD.getActivePath().front().getPtr(); 1612 C = cast<PathDiagnosticCallPiece>(P); 1613 } else { 1614 const Decl *Caller = CE->getLocationContext()->getDecl(); 1615 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1616 1617 // Since we just transferred the path over to the call piece, 1618 // reset the mapping from active to location context. 1619 assert(PD.getActivePath().size() == 1 && 1620 PD.getActivePath().front() == C); 1621 LCM[&PD.getActivePath()] = 0; 1622 1623 // Record the location context mapping for the path within 1624 // the call. 1625 assert(LCM[&C->path] == 0 || 1626 LCM[&C->path] == CE->getCalleeContext()); 1627 LCM[&C->path] = CE->getCalleeContext(); 1628 1629 // If this is the first item in the active path, record 1630 // the new mapping from active path to location context. 1631 const LocationContext *&NewLC = LCM[&PD.getActivePath()]; 1632 if (!NewLC) { 1633 NewLC = N->getLocationContext(); 1634 } 1635 PDB.LC = NewLC; 1636 1637 // Update the previous location in the active path 1638 // since we just created the call piece lazily. 1639 PrevLocMap[PDB.LC->getCurrentStackFrame()] = C->getLocation(); 1640 } 1641 C->setCallee(*CE, SM); 1642 1643 if (!CallStack.empty()) { 1644 assert(CallStack.back().first == C); 1645 CallStack.pop_back(); 1646 } 1647 break; 1648 } 1649 1650 // Query the location context here and the previous location 1651 // as processing CallEnter may change the active path. 1652 PDB.LC = N->getLocationContext(); 1653 1654 // Get the previous location for the current active 1655 // location context. All edges will be based on this 1656 // location, and it will be updated in place. 1657 PathDiagnosticLocation &PrevLoc = 1658 PrevLocMap[PDB.LC->getCurrentStackFrame()]; 1659 1660 // Record the mapping from the active path to the location 1661 // context. 1662 assert(!LCM[&PD.getActivePath()] || 1663 LCM[&PD.getActivePath()] == PDB.LC); 1664 LCM[&PD.getActivePath()] = PDB.LC; 1665 1666 // Have we encountered an exit from a function call? 1667 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1668 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1669 // Propagate the interesting symbols accordingly. 1670 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1671 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1672 N->getState().getPtr(), Ex, 1673 N->getLocationContext()); 1674 } 1675 1676 // We are descending into a call (backwards). Construct 1677 // a new call piece to contain the path pieces for that call. 1678 PathDiagnosticCallPiece *C = 1679 PathDiagnosticCallPiece::construct(N, *CE, SM); 1680 1681 // Record the location context for this call piece. 1682 LCM[&C->path] = CE->getCalleeContext(); 1683 1684 // Add the edge to the return site. 1685 addEdgeToPath(PD.getActivePath(), PrevLoc, C->callReturn, PDB.LC); 1686 PD.getActivePath().push_front(C); 1687 1688 // Make the contents of the call the active path for now. 1689 PD.pushActivePath(&C->path); 1690 CallStack.push_back(StackDiagPair(C, N)); 1691 break; 1692 } 1693 1694 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1695 // For expressions, make sure we propagate the 1696 // interesting symbols correctly. 1697 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1698 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1699 N->getState().getPtr(), Ex, 1700 N->getLocationContext()); 1701 1702 PathDiagnosticLocation L = 1703 PathDiagnosticLocation(PS->getStmt(), SM, PDB.LC); 1704 addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC); 1705 break; 1706 } 1707 1708 // Block edges. 1709 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1710 // Does this represent entering a call? If so, look at propagating 1711 // interesting symbols across call boundaries. 1712 if (NextNode) { 1713 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1714 const LocationContext *CalleeCtx = PDB.LC; 1715 if (CallerCtx != CalleeCtx) { 1716 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1717 N->getState().getPtr(), 1718 CalleeCtx, CallerCtx); 1719 } 1720 } 1721 1722 // Are we jumping to the head of a loop? Add a special diagnostic. 1723 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1724 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1725 const CompoundStmt *CS = NULL; 1726 1727 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1728 CS = dyn_cast<CompoundStmt>(FS->getBody()); 1729 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1730 CS = dyn_cast<CompoundStmt>(WS->getBody()); 1731 1732 PathDiagnosticEventPiece *p = 1733 new PathDiagnosticEventPiece(L, "Looping back to the head " 1734 "of the loop"); 1735 p->setPrunable(true); 1736 1737 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC); 1738 PD.getActivePath().push_front(p); 1739 1740 if (CS) { 1741 addEdgeToPath(PD.getActivePath(), PrevLoc, 1742 PathDiagnosticLocation::createEndBrace(CS, SM), 1743 PDB.LC); 1744 } 1745 } 1746 1747 const CFGBlock *BSrc = BE->getSrc(); 1748 ParentMap &PM = PDB.getParentMap(); 1749 1750 if (const Stmt *Term = BSrc->getTerminator()) { 1751 // Are we jumping past the loop body without ever executing the 1752 // loop (because the condition was false)? 1753 if (isLoop(Term)) { 1754 const Stmt *TermCond = BSrc->getTerminatorCondition(); 1755 bool IsInLoopBody = 1756 isInLoopBody(PM, getStmtBeforeCond(PM, TermCond, N), Term); 1757 1758 const char *str = 0; 1759 1760 if (isJumpToFalseBranch(&*BE)) { 1761 if (!IsInLoopBody) { 1762 str = "Loop body executed 0 times"; 1763 } 1764 } 1765 else { 1766 str = "Entering loop body"; 1767 } 1768 1769 if (str) { 1770 PathDiagnosticLocation L(TermCond, SM, PDB.LC); 1771 PathDiagnosticEventPiece *PE = 1772 new PathDiagnosticEventPiece(L, str); 1773 PE->setPrunable(true); 1774 addEdgeToPath(PD.getActivePath(), PrevLoc, 1775 PE->getLocation(), PDB.LC); 1776 PD.getActivePath().push_front(PE); 1777 } 1778 } 1779 else if (isa<BreakStmt>(Term) || isa<ContinueStmt>(Term) || 1780 isa<GotoStmt>(Term)) { 1781 PathDiagnosticLocation L(Term, SM, PDB.LC); 1782 addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC); 1783 } 1784 } 1785 break; 1786 } 1787 } while (0); 1788 1789 if (!NextNode) 1790 continue; 1791 1792 // Since the active path may have been updated prior 1793 // to this point, query the active location context now. 1794 PathDiagnosticLocation &PrevLoc = 1795 PrevLocMap[PDB.LC->getCurrentStackFrame()]; 1796 1797 // Add pieces from custom visitors. 1798 for (ArrayRef<BugReporterVisitor *>::iterator I = visitors.begin(), 1799 E = visitors.end(); 1800 I != E; ++I) { 1801 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *report)) { 1802 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC); 1803 PD.getActivePath().push_front(p); 1804 updateStackPiecesWithMessage(p, CallStack); 1805 } 1806 } 1807 } 1808 1809 return report->isValid(); 1810} 1811 1812const Stmt *getLocStmt(PathDiagnosticLocation L) { 1813 if (!L.isValid()) 1814 return 0; 1815 return L.asStmt(); 1816} 1817 1818const Stmt *getStmtParent(const Stmt *S, ParentMap &PM) { 1819 if (!S) 1820 return 0; 1821 return PM.getParentIgnoreParens(S); 1822} 1823 1824static bool isConditionForTerminator(const Stmt *S, const Stmt *Cond) { 1825 switch (S->getStmtClass()) { 1826 case Stmt::BinaryOperatorClass: { 1827 const BinaryOperator *BO = cast<BinaryOperator>(S); 1828 if (!BO->isLogicalOp()) 1829 return false; 1830 return BO->getLHS() == Cond || BO->getRHS() == Cond; 1831 } 1832 case Stmt::IfStmtClass: 1833 return cast<IfStmt>(S)->getCond() == Cond; 1834 case Stmt::ForStmtClass: 1835 return cast<ForStmt>(S)->getCond() == Cond; 1836 case Stmt::WhileStmtClass: 1837 return cast<WhileStmt>(S)->getCond() == Cond; 1838 case Stmt::DoStmtClass: 1839 return cast<DoStmt>(S)->getCond() == Cond; 1840 case Stmt::ChooseExprClass: 1841 return cast<ChooseExpr>(S)->getCond() == Cond; 1842 case Stmt::IndirectGotoStmtClass: 1843 return cast<IndirectGotoStmt>(S)->getTarget() == Cond; 1844 case Stmt::SwitchStmtClass: 1845 return cast<SwitchStmt>(S)->getCond() == Cond; 1846 case Stmt::BinaryConditionalOperatorClass: 1847 return cast<BinaryConditionalOperator>(S)->getCond() == Cond; 1848 case Stmt::ConditionalOperatorClass: { 1849 const ConditionalOperator *CO = cast<ConditionalOperator>(S); 1850 return CO->getCond() == Cond || 1851 CO->getLHS() == Cond || 1852 CO->getRHS() == Cond; 1853 } 1854 case Stmt::ObjCForCollectionStmtClass: 1855 return cast<ObjCForCollectionStmt>(S)->getElement() == Cond; 1856 default: 1857 return false; 1858 } 1859} 1860 1861static bool isIncrementOrInitInForLoop(const Stmt *S, const Stmt *FL) { 1862 const ForStmt *FS = dyn_cast<ForStmt>(FL); 1863 if (!FS) 1864 return false; 1865 return FS->getInc() == S || FS->getInit() == S; 1866} 1867 1868typedef llvm::DenseSet<const PathDiagnosticCallPiece *> 1869 OptimizedCallsSet; 1870 1871static bool optimizeEdges(PathPieces &path, SourceManager &SM, 1872 OptimizedCallsSet &OCS, 1873 LocationContextMap &LCM) { 1874 bool hasChanges = false; 1875 const LocationContext *LC = LCM[&path]; 1876 assert(LC); 1877 bool isFirst = true; 1878 1879 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ) { 1880 bool wasFirst = isFirst; 1881 isFirst = false; 1882 1883 // Optimize subpaths. 1884 if (PathDiagnosticCallPiece *CallI = dyn_cast<PathDiagnosticCallPiece>(*I)){ 1885 // Record the fact that a call has been optimized so we only do the 1886 // effort once. 1887 if (!OCS.count(CallI)) { 1888 while (optimizeEdges(CallI->path, SM, OCS, LCM)) {} 1889 OCS.insert(CallI); 1890 } 1891 ++I; 1892 continue; 1893 } 1894 1895 // Pattern match the current piece and its successor. 1896 PathDiagnosticControlFlowPiece *PieceI = 1897 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 1898 1899 if (!PieceI) { 1900 ++I; 1901 continue; 1902 } 1903 1904 ParentMap &PM = LC->getParentMap(); 1905 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation()); 1906 const Stmt *s1End = getLocStmt(PieceI->getEndLocation()); 1907 const Stmt *level1 = getStmtParent(s1Start, PM); 1908 const Stmt *level2 = getStmtParent(s1End, PM); 1909 1910 if (wasFirst) { 1911 wasFirst = false; 1912 1913 // If the first edge (in isolation) is just a transition from 1914 // an expression to a parent expression then eliminate that edge. 1915 if (level1 && level2 && level2 == PM.getParent(level1)) { 1916 path.erase(I); 1917 // Since we are erasing the current edge at the start of the 1918 // path, just return now so we start analyzing the start of the path 1919 // again. 1920 return true; 1921 } 1922 1923 // If the first edge (in isolation) is a transition from the 1924 // initialization or increment in a for loop then remove it. 1925 if (level1 && isIncrementOrInitInForLoop(s1Start, level1)) { 1926 path.erase(I); 1927 return true; 1928 } 1929 } 1930 1931 PathPieces::iterator NextI = I; ++NextI; 1932 if (NextI == E) 1933 break; 1934 1935 PathDiagnosticControlFlowPiece *PieceNextI = 1936 dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 1937 1938 if (!PieceNextI) { 1939 ++I; 1940 continue; 1941 } 1942 1943 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation()); 1944 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation()); 1945 const Stmt *level3 = getStmtParent(s2Start, PM); 1946 const Stmt *level4 = getStmtParent(s2End, PM); 1947 1948 // Rule I. 1949 // 1950 // If we have two consecutive control edges whose end/begin locations 1951 // are at the same level (e.g. statements or top-level expressions within 1952 // a compound statement, or siblings share a single ancestor expression), 1953 // then merge them if they have no interesting intermediate event. 1954 // 1955 // For example: 1956 // 1957 // (1.1 -> 1.2) -> (1.2 -> 1.3) becomes (1.1 -> 1.3) because the common 1958 // parent is '1'. Here 'x.y.z' represents the hierarchy of statements. 1959 // 1960 // NOTE: this will be limited later in cases where we add barriers 1961 // to prevent this optimization. 1962 // 1963 if (level1 && level1 == level2 && level1 == level3 && level1 == level4) { 1964 PieceI->setEndLocation(PieceNextI->getEndLocation()); 1965 path.erase(NextI); 1966 hasChanges = true; 1967 continue; 1968 } 1969 1970 // Rule II. 1971 // 1972 // Eliminate edges between subexpressions and parent expressions 1973 // when the subexpression is consumed. 1974 // 1975 // NOTE: this will be limited later in cases where we add barriers 1976 // to prevent this optimization. 1977 // 1978 if (s1End && s1End == s2Start && level2) { 1979 if (isIncrementOrInitInForLoop(s1End, level2) || 1980 (isa<Expr>(s1End) && PM.isConsumedExpr(cast<Expr>(s1End)) && 1981 !isConditionForTerminator(level2, s1End))) 1982 { 1983 PieceI->setEndLocation(PieceNextI->getEndLocation()); 1984 path.erase(NextI); 1985 hasChanges = true; 1986 continue; 1987 } 1988 } 1989 1990 // No changes at this index? Move to the next one. 1991 ++I; 1992 } 1993 1994 // No changes. 1995 return hasChanges; 1996} 1997 1998static void adjustLoopEdges(PathPieces &pieces, LocationContextMap &LCM, 1999 SourceManager &SM) { 2000 // Retrieve the parent map for this path. 2001 const LocationContext *LC = LCM[&pieces]; 2002 ParentMap &PM = LC->getParentMap(); 2003 PathPieces::iterator Prev = pieces.end(); 2004 for (PathPieces::iterator I = pieces.begin(), E = pieces.end(); I != E; 2005 Prev = I, ++I) { 2006 // Adjust edges in subpaths. 2007 if (PathDiagnosticCallPiece *Call = dyn_cast<PathDiagnosticCallPiece>(*I)) { 2008 adjustLoopEdges(Call->path, LCM, SM); 2009 continue; 2010 } 2011 2012 PathDiagnosticControlFlowPiece *PieceI = 2013 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2014 2015 if (!PieceI) 2016 continue; 2017 2018 // We are looking at two edges. Is the second one incident 2019 // on an expression (or subexpression) of a loop condition. 2020 const Stmt *Dst = getLocStmt(PieceI->getEndLocation()); 2021 const Stmt *Src = getLocStmt(PieceI->getStartLocation()); 2022 2023 if (!Dst || !Src) 2024 continue; 2025 2026 const Stmt *Loop = 0; 2027 const Stmt *S = Dst; 2028 while (const Stmt *Parent = PM.getParentIgnoreParens(S)) { 2029 if (const ForStmt *FS = dyn_cast<ForStmt>(Parent)) { 2030 if (FS->getCond()->IgnoreParens() == S) 2031 Loop = FS; 2032 break; 2033 } 2034 if (const WhileStmt *WS = dyn_cast<WhileStmt>(Parent)) { 2035 if (WS->getCond()->IgnoreParens() == S) 2036 Loop = WS; 2037 break; 2038 } 2039 S = Parent; 2040 } 2041 2042 // If 'Loop' is non-null we have found a match where we have an edge 2043 // incident on the condition of a for/while statement. 2044 if (!Loop) 2045 continue; 2046 2047 // If the current source of the edge is the 'for'/'while', then there is 2048 // nothing left to be done. 2049 if (Src == Loop) 2050 continue; 2051 2052 // Now look at the previous edge. We want to know if this was in the same 2053 // "level" as the for statement. 2054 const Stmt *SrcParent = PM.getParentIgnoreParens(Src); 2055 const Stmt *FSParent = PM.getParentIgnoreParens(Loop); 2056 if (SrcParent && SrcParent == FSParent) { 2057 PathDiagnosticLocation L(Loop, SM, LC); 2058 bool needsEdge = true; 2059 2060 if (Prev != E) { 2061 if (PathDiagnosticControlFlowPiece *P = 2062 dyn_cast<PathDiagnosticControlFlowPiece>(*Prev)) { 2063 const Stmt *PrevSrc = getLocStmt(P->getStartLocation()); 2064 if (PrevSrc) { 2065 const Stmt *PrevSrcParent = PM.getParentIgnoreParens(PrevSrc); 2066 if (PrevSrcParent == FSParent) { 2067 P->setEndLocation(L); 2068 needsEdge = false; 2069 } 2070 } 2071 } 2072 } 2073 2074 if (needsEdge) { 2075 PathDiagnosticControlFlowPiece *P = 2076 new PathDiagnosticControlFlowPiece(PieceI->getStartLocation(), L); 2077 pieces.insert(I, P); 2078 } 2079 2080 PieceI->setStartLocation(L); 2081 } 2082 } 2083} 2084 2085//===----------------------------------------------------------------------===// 2086// Methods for BugType and subclasses. 2087//===----------------------------------------------------------------------===// 2088BugType::~BugType() { } 2089 2090void BugType::FlushReports(BugReporter &BR) {} 2091 2092void BuiltinBug::anchor() {} 2093 2094//===----------------------------------------------------------------------===// 2095// Methods for BugReport and subclasses. 2096//===----------------------------------------------------------------------===// 2097 2098void BugReport::NodeResolver::anchor() {} 2099 2100void BugReport::addVisitor(BugReporterVisitor* visitor) { 2101 if (!visitor) 2102 return; 2103 2104 llvm::FoldingSetNodeID ID; 2105 visitor->Profile(ID); 2106 void *InsertPos; 2107 2108 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) { 2109 delete visitor; 2110 return; 2111 } 2112 2113 CallbacksSet.InsertNode(visitor, InsertPos); 2114 Callbacks.push_back(visitor); 2115 ++ConfigurationChangeToken; 2116} 2117 2118BugReport::~BugReport() { 2119 for (visitor_iterator I = visitor_begin(), E = visitor_end(); I != E; ++I) { 2120 delete *I; 2121 } 2122 while (!interestingSymbols.empty()) { 2123 popInterestingSymbolsAndRegions(); 2124 } 2125} 2126 2127const Decl *BugReport::getDeclWithIssue() const { 2128 if (DeclWithIssue) 2129 return DeclWithIssue; 2130 2131 const ExplodedNode *N = getErrorNode(); 2132 if (!N) 2133 return 0; 2134 2135 const LocationContext *LC = N->getLocationContext(); 2136 return LC->getCurrentStackFrame()->getDecl(); 2137} 2138 2139void BugReport::Profile(llvm::FoldingSetNodeID& hash) const { 2140 hash.AddPointer(&BT); 2141 hash.AddString(Description); 2142 PathDiagnosticLocation UL = getUniqueingLocation(); 2143 if (UL.isValid()) { 2144 UL.Profile(hash); 2145 } else if (Location.isValid()) { 2146 Location.Profile(hash); 2147 } else { 2148 assert(ErrorNode); 2149 hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode)); 2150 } 2151 2152 for (SmallVectorImpl<SourceRange>::const_iterator I = 2153 Ranges.begin(), E = Ranges.end(); I != E; ++I) { 2154 const SourceRange range = *I; 2155 if (!range.isValid()) 2156 continue; 2157 hash.AddInteger(range.getBegin().getRawEncoding()); 2158 hash.AddInteger(range.getEnd().getRawEncoding()); 2159 } 2160} 2161 2162void BugReport::markInteresting(SymbolRef sym) { 2163 if (!sym) 2164 return; 2165 2166 // If the symbol wasn't already in our set, note a configuration change. 2167 if (getInterestingSymbols().insert(sym).second) 2168 ++ConfigurationChangeToken; 2169 2170 if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym)) 2171 getInterestingRegions().insert(meta->getRegion()); 2172} 2173 2174void BugReport::markInteresting(const MemRegion *R) { 2175 if (!R) 2176 return; 2177 2178 // If the base region wasn't already in our set, note a configuration change. 2179 R = R->getBaseRegion(); 2180 if (getInterestingRegions().insert(R).second) 2181 ++ConfigurationChangeToken; 2182 2183 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2184 getInterestingSymbols().insert(SR->getSymbol()); 2185} 2186 2187void BugReport::markInteresting(SVal V) { 2188 markInteresting(V.getAsRegion()); 2189 markInteresting(V.getAsSymbol()); 2190} 2191 2192void BugReport::markInteresting(const LocationContext *LC) { 2193 if (!LC) 2194 return; 2195 InterestingLocationContexts.insert(LC); 2196} 2197 2198bool BugReport::isInteresting(SVal V) { 2199 return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol()); 2200} 2201 2202bool BugReport::isInteresting(SymbolRef sym) { 2203 if (!sym) 2204 return false; 2205 // We don't currently consider metadata symbols to be interesting 2206 // even if we know their region is interesting. Is that correct behavior? 2207 return getInterestingSymbols().count(sym); 2208} 2209 2210bool BugReport::isInteresting(const MemRegion *R) { 2211 if (!R) 2212 return false; 2213 R = R->getBaseRegion(); 2214 bool b = getInterestingRegions().count(R); 2215 if (b) 2216 return true; 2217 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2218 return getInterestingSymbols().count(SR->getSymbol()); 2219 return false; 2220} 2221 2222bool BugReport::isInteresting(const LocationContext *LC) { 2223 if (!LC) 2224 return false; 2225 return InterestingLocationContexts.count(LC); 2226} 2227 2228void BugReport::lazyInitializeInterestingSets() { 2229 if (interestingSymbols.empty()) { 2230 interestingSymbols.push_back(new Symbols()); 2231 interestingRegions.push_back(new Regions()); 2232 } 2233} 2234 2235BugReport::Symbols &BugReport::getInterestingSymbols() { 2236 lazyInitializeInterestingSets(); 2237 return *interestingSymbols.back(); 2238} 2239 2240BugReport::Regions &BugReport::getInterestingRegions() { 2241 lazyInitializeInterestingSets(); 2242 return *interestingRegions.back(); 2243} 2244 2245void BugReport::pushInterestingSymbolsAndRegions() { 2246 interestingSymbols.push_back(new Symbols(getInterestingSymbols())); 2247 interestingRegions.push_back(new Regions(getInterestingRegions())); 2248} 2249 2250void BugReport::popInterestingSymbolsAndRegions() { 2251 delete interestingSymbols.back(); 2252 interestingSymbols.pop_back(); 2253 delete interestingRegions.back(); 2254 interestingRegions.pop_back(); 2255} 2256 2257const Stmt *BugReport::getStmt() const { 2258 if (!ErrorNode) 2259 return 0; 2260 2261 ProgramPoint ProgP = ErrorNode->getLocation(); 2262 const Stmt *S = NULL; 2263 2264 if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) { 2265 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit(); 2266 if (BE->getBlock() == &Exit) 2267 S = GetPreviousStmt(ErrorNode); 2268 } 2269 if (!S) 2270 S = PathDiagnosticLocation::getStmt(ErrorNode); 2271 2272 return S; 2273} 2274 2275std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator> 2276BugReport::getRanges() { 2277 // If no custom ranges, add the range of the statement corresponding to 2278 // the error node. 2279 if (Ranges.empty()) { 2280 if (const Expr *E = dyn_cast_or_null<Expr>(getStmt())) 2281 addRange(E->getSourceRange()); 2282 else 2283 return std::make_pair(ranges_iterator(), ranges_iterator()); 2284 } 2285 2286 // User-specified absence of range info. 2287 if (Ranges.size() == 1 && !Ranges.begin()->isValid()) 2288 return std::make_pair(ranges_iterator(), ranges_iterator()); 2289 2290 return std::make_pair(Ranges.begin(), Ranges.end()); 2291} 2292 2293PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const { 2294 if (ErrorNode) { 2295 assert(!Location.isValid() && 2296 "Either Location or ErrorNode should be specified but not both."); 2297 return PathDiagnosticLocation::createEndOfPath(ErrorNode, SM); 2298 } else { 2299 assert(Location.isValid()); 2300 return Location; 2301 } 2302 2303 return PathDiagnosticLocation(); 2304} 2305 2306//===----------------------------------------------------------------------===// 2307// Methods for BugReporter and subclasses. 2308//===----------------------------------------------------------------------===// 2309 2310BugReportEquivClass::~BugReportEquivClass() { } 2311GRBugReporter::~GRBugReporter() { } 2312BugReporterData::~BugReporterData() {} 2313 2314ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); } 2315 2316ProgramStateManager& 2317GRBugReporter::getStateManager() { return Eng.getStateManager(); } 2318 2319BugReporter::~BugReporter() { 2320 FlushReports(); 2321 2322 // Free the bug reports we are tracking. 2323 typedef std::vector<BugReportEquivClass *> ContTy; 2324 for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end(); 2325 I != E; ++I) { 2326 delete *I; 2327 } 2328} 2329 2330void BugReporter::FlushReports() { 2331 if (BugTypes.isEmpty()) 2332 return; 2333 2334 // First flush the warnings for each BugType. This may end up creating new 2335 // warnings and new BugTypes. 2336 // FIXME: Only NSErrorChecker needs BugType's FlushReports. 2337 // Turn NSErrorChecker into a proper checker and remove this. 2338 SmallVector<const BugType*, 16> bugTypes; 2339 for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I) 2340 bugTypes.push_back(*I); 2341 for (SmallVector<const BugType*, 16>::iterator 2342 I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I) 2343 const_cast<BugType*>(*I)->FlushReports(*this); 2344 2345 // We need to flush reports in deterministic order to ensure the order 2346 // of the reports is consistent between runs. 2347 typedef std::vector<BugReportEquivClass *> ContVecTy; 2348 for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end(); 2349 EI != EE; ++EI){ 2350 BugReportEquivClass& EQ = **EI; 2351 FlushReport(EQ); 2352 } 2353 2354 // BugReporter owns and deletes only BugTypes created implicitly through 2355 // EmitBasicReport. 2356 // FIXME: There are leaks from checkers that assume that the BugTypes they 2357 // create will be destroyed by the BugReporter. 2358 for (llvm::StringMap<BugType*>::iterator 2359 I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I) 2360 delete I->second; 2361 2362 // Remove all references to the BugType objects. 2363 BugTypes = F.getEmptySet(); 2364} 2365 2366//===----------------------------------------------------------------------===// 2367// PathDiagnostics generation. 2368//===----------------------------------------------------------------------===// 2369 2370namespace { 2371/// A wrapper around a report graph, which contains only a single path, and its 2372/// node maps. 2373class ReportGraph { 2374public: 2375 InterExplodedGraphMap BackMap; 2376 OwningPtr<ExplodedGraph> Graph; 2377 const ExplodedNode *ErrorNode; 2378 size_t Index; 2379}; 2380 2381/// A wrapper around a trimmed graph and its node maps. 2382class TrimmedGraph { 2383 InterExplodedGraphMap InverseMap; 2384 2385 typedef llvm::DenseMap<const ExplodedNode *, unsigned> PriorityMapTy; 2386 PriorityMapTy PriorityMap; 2387 2388 typedef std::pair<const ExplodedNode *, size_t> NodeIndexPair; 2389 SmallVector<NodeIndexPair, 32> ReportNodes; 2390 2391 OwningPtr<ExplodedGraph> G; 2392 2393 /// A helper class for sorting ExplodedNodes by priority. 2394 template <bool Descending> 2395 class PriorityCompare { 2396 const PriorityMapTy &PriorityMap; 2397 2398 public: 2399 PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {} 2400 2401 bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const { 2402 PriorityMapTy::const_iterator LI = PriorityMap.find(LHS); 2403 PriorityMapTy::const_iterator RI = PriorityMap.find(RHS); 2404 PriorityMapTy::const_iterator E = PriorityMap.end(); 2405 2406 if (LI == E) 2407 return Descending; 2408 if (RI == E) 2409 return !Descending; 2410 2411 return Descending ? LI->second > RI->second 2412 : LI->second < RI->second; 2413 } 2414 2415 bool operator()(const NodeIndexPair &LHS, const NodeIndexPair &RHS) const { 2416 return (*this)(LHS.first, RHS.first); 2417 } 2418 }; 2419 2420public: 2421 TrimmedGraph(const ExplodedGraph *OriginalGraph, 2422 ArrayRef<const ExplodedNode *> Nodes); 2423 2424 bool popNextReportGraph(ReportGraph &GraphWrapper); 2425}; 2426} 2427 2428TrimmedGraph::TrimmedGraph(const ExplodedGraph *OriginalGraph, 2429 ArrayRef<const ExplodedNode *> Nodes) { 2430 // The trimmed graph is created in the body of the constructor to ensure 2431 // that the DenseMaps have been initialized already. 2432 InterExplodedGraphMap ForwardMap; 2433 G.reset(OriginalGraph->trim(Nodes, &ForwardMap, &InverseMap)); 2434 2435 // Find the (first) error node in the trimmed graph. We just need to consult 2436 // the node map which maps from nodes in the original graph to nodes 2437 // in the new graph. 2438 llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes; 2439 2440 for (unsigned i = 0, count = Nodes.size(); i < count; ++i) { 2441 if (const ExplodedNode *NewNode = ForwardMap.lookup(Nodes[i])) { 2442 ReportNodes.push_back(std::make_pair(NewNode, i)); 2443 RemainingNodes.insert(NewNode); 2444 } 2445 } 2446 2447 assert(!RemainingNodes.empty() && "No error node found in the trimmed graph"); 2448 2449 // Perform a forward BFS to find all the shortest paths. 2450 std::queue<const ExplodedNode *> WS; 2451 2452 assert(G->num_roots() == 1); 2453 WS.push(*G->roots_begin()); 2454 unsigned Priority = 0; 2455 2456 while (!WS.empty()) { 2457 const ExplodedNode *Node = WS.front(); 2458 WS.pop(); 2459 2460 PriorityMapTy::iterator PriorityEntry; 2461 bool IsNew; 2462 llvm::tie(PriorityEntry, IsNew) = 2463 PriorityMap.insert(std::make_pair(Node, Priority)); 2464 ++Priority; 2465 2466 if (!IsNew) { 2467 assert(PriorityEntry->second <= Priority); 2468 continue; 2469 } 2470 2471 if (RemainingNodes.erase(Node)) 2472 if (RemainingNodes.empty()) 2473 break; 2474 2475 for (ExplodedNode::const_pred_iterator I = Node->succ_begin(), 2476 E = Node->succ_end(); 2477 I != E; ++I) 2478 WS.push(*I); 2479 } 2480 2481 // Sort the error paths from longest to shortest. 2482 std::sort(ReportNodes.begin(), ReportNodes.end(), 2483 PriorityCompare<true>(PriorityMap)); 2484} 2485 2486bool TrimmedGraph::popNextReportGraph(ReportGraph &GraphWrapper) { 2487 if (ReportNodes.empty()) 2488 return false; 2489 2490 const ExplodedNode *OrigN; 2491 llvm::tie(OrigN, GraphWrapper.Index) = ReportNodes.pop_back_val(); 2492 assert(PriorityMap.find(OrigN) != PriorityMap.end() && 2493 "error node not accessible from root"); 2494 2495 // Create a new graph with a single path. This is the graph 2496 // that will be returned to the caller. 2497 ExplodedGraph *GNew = new ExplodedGraph(); 2498 GraphWrapper.Graph.reset(GNew); 2499 GraphWrapper.BackMap.clear(); 2500 2501 // Now walk from the error node up the BFS path, always taking the 2502 // predeccessor with the lowest number. 2503 ExplodedNode *Succ = 0; 2504 while (true) { 2505 // Create the equivalent node in the new graph with the same state 2506 // and location. 2507 ExplodedNode *NewN = GNew->getNode(OrigN->getLocation(), OrigN->getState(), 2508 OrigN->isSink()); 2509 2510 // Store the mapping to the original node. 2511 InterExplodedGraphMap::const_iterator IMitr = InverseMap.find(OrigN); 2512 assert(IMitr != InverseMap.end() && "No mapping to original node."); 2513 GraphWrapper.BackMap[NewN] = IMitr->second; 2514 2515 // Link up the new node with the previous node. 2516 if (Succ) 2517 Succ->addPredecessor(NewN, *GNew); 2518 else 2519 GraphWrapper.ErrorNode = NewN; 2520 2521 Succ = NewN; 2522 2523 // Are we at the final node? 2524 if (OrigN->pred_empty()) { 2525 GNew->addRoot(NewN); 2526 break; 2527 } 2528 2529 // Find the next predeccessor node. We choose the node that is marked 2530 // with the lowest BFS number. 2531 OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(), 2532 PriorityCompare<false>(PriorityMap)); 2533 } 2534 2535 return true; 2536} 2537 2538 2539/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object 2540/// and collapses PathDiagosticPieces that are expanded by macros. 2541static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) { 2542 typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>, 2543 SourceLocation> > MacroStackTy; 2544 2545 typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> > 2546 PiecesTy; 2547 2548 MacroStackTy MacroStack; 2549 PiecesTy Pieces; 2550 2551 for (PathPieces::const_iterator I = path.begin(), E = path.end(); 2552 I!=E; ++I) { 2553 2554 PathDiagnosticPiece *piece = I->getPtr(); 2555 2556 // Recursively compact calls. 2557 if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){ 2558 CompactPathDiagnostic(call->path, SM); 2559 } 2560 2561 // Get the location of the PathDiagnosticPiece. 2562 const FullSourceLoc Loc = piece->getLocation().asLocation(); 2563 2564 // Determine the instantiation location, which is the location we group 2565 // related PathDiagnosticPieces. 2566 SourceLocation InstantiationLoc = Loc.isMacroID() ? 2567 SM.getExpansionLoc(Loc) : 2568 SourceLocation(); 2569 2570 if (Loc.isFileID()) { 2571 MacroStack.clear(); 2572 Pieces.push_back(piece); 2573 continue; 2574 } 2575 2576 assert(Loc.isMacroID()); 2577 2578 // Is the PathDiagnosticPiece within the same macro group? 2579 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) { 2580 MacroStack.back().first->subPieces.push_back(piece); 2581 continue; 2582 } 2583 2584 // We aren't in the same group. Are we descending into a new macro 2585 // or are part of an old one? 2586 IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup; 2587 2588 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ? 2589 SM.getExpansionLoc(Loc) : 2590 SourceLocation(); 2591 2592 // Walk the entire macro stack. 2593 while (!MacroStack.empty()) { 2594 if (InstantiationLoc == MacroStack.back().second) { 2595 MacroGroup = MacroStack.back().first; 2596 break; 2597 } 2598 2599 if (ParentInstantiationLoc == MacroStack.back().second) { 2600 MacroGroup = MacroStack.back().first; 2601 break; 2602 } 2603 2604 MacroStack.pop_back(); 2605 } 2606 2607 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) { 2608 // Create a new macro group and add it to the stack. 2609 PathDiagnosticMacroPiece *NewGroup = 2610 new PathDiagnosticMacroPiece( 2611 PathDiagnosticLocation::createSingleLocation(piece->getLocation())); 2612 2613 if (MacroGroup) 2614 MacroGroup->subPieces.push_back(NewGroup); 2615 else { 2616 assert(InstantiationLoc.isFileID()); 2617 Pieces.push_back(NewGroup); 2618 } 2619 2620 MacroGroup = NewGroup; 2621 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc)); 2622 } 2623 2624 // Finally, add the PathDiagnosticPiece to the group. 2625 MacroGroup->subPieces.push_back(piece); 2626 } 2627 2628 // Now take the pieces and construct a new PathDiagnostic. 2629 path.clear(); 2630 2631 for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I) 2632 path.push_back(*I); 2633} 2634 2635bool GRBugReporter::generatePathDiagnostic(PathDiagnostic& PD, 2636 PathDiagnosticConsumer &PC, 2637 ArrayRef<BugReport *> &bugReports) { 2638 assert(!bugReports.empty()); 2639 2640 bool HasValid = false; 2641 bool HasInvalid = false; 2642 SmallVector<const ExplodedNode *, 32> errorNodes; 2643 for (ArrayRef<BugReport*>::iterator I = bugReports.begin(), 2644 E = bugReports.end(); I != E; ++I) { 2645 if ((*I)->isValid()) { 2646 HasValid = true; 2647 errorNodes.push_back((*I)->getErrorNode()); 2648 } else { 2649 // Keep the errorNodes list in sync with the bugReports list. 2650 HasInvalid = true; 2651 errorNodes.push_back(0); 2652 } 2653 } 2654 2655 // If all the reports have been marked invalid by a previous path generation, 2656 // we're done. 2657 if (!HasValid) 2658 return false; 2659 2660 typedef PathDiagnosticConsumer::PathGenerationScheme PathGenerationScheme; 2661 PathGenerationScheme ActiveScheme = PC.getGenerationScheme(); 2662 2663 if (ActiveScheme == PathDiagnosticConsumer::Extensive) { 2664 AnalyzerOptions &options = getEngine().getAnalysisManager().options; 2665 if (options.getBooleanOption("path-diagnostics-alternate", false)) { 2666 ActiveScheme = PathDiagnosticConsumer::AlternateExtensive; 2667 } 2668 } 2669 2670 TrimmedGraph TrimG(&getGraph(), errorNodes); 2671 ReportGraph ErrorGraph; 2672 2673 while (TrimG.popNextReportGraph(ErrorGraph)) { 2674 // Find the BugReport with the original location. 2675 assert(ErrorGraph.Index < bugReports.size()); 2676 BugReport *R = bugReports[ErrorGraph.Index]; 2677 assert(R && "No original report found for sliced graph."); 2678 assert(R->isValid() && "Report selected by trimmed graph marked invalid."); 2679 2680 // Start building the path diagnostic... 2681 PathDiagnosticBuilder PDB(*this, R, ErrorGraph.BackMap, &PC); 2682 const ExplodedNode *N = ErrorGraph.ErrorNode; 2683 2684 // Register additional node visitors. 2685 R->addVisitor(new NilReceiverBRVisitor()); 2686 R->addVisitor(new ConditionBRVisitor()); 2687 R->addVisitor(new LikelyFalsePositiveSuppressionBRVisitor()); 2688 2689 BugReport::VisitorList visitors; 2690 unsigned origReportConfigToken, finalReportConfigToken; 2691 LocationContextMap LCM; 2692 2693 // While generating diagnostics, it's possible the visitors will decide 2694 // new symbols and regions are interesting, or add other visitors based on 2695 // the information they find. If they do, we need to regenerate the path 2696 // based on our new report configuration. 2697 do { 2698 // Get a clean copy of all the visitors. 2699 for (BugReport::visitor_iterator I = R->visitor_begin(), 2700 E = R->visitor_end(); I != E; ++I) 2701 visitors.push_back((*I)->clone()); 2702 2703 // Clear out the active path from any previous work. 2704 PD.resetPath(); 2705 origReportConfigToken = R->getConfigurationChangeToken(); 2706 2707 // Generate the very last diagnostic piece - the piece is visible before 2708 // the trace is expanded. 2709 PathDiagnosticPiece *LastPiece = 0; 2710 for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end(); 2711 I != E; ++I) { 2712 if (PathDiagnosticPiece *Piece = (*I)->getEndPath(PDB, N, *R)) { 2713 assert (!LastPiece && 2714 "There can only be one final piece in a diagnostic."); 2715 LastPiece = Piece; 2716 } 2717 } 2718 2719 if (ActiveScheme != PathDiagnosticConsumer::None) { 2720 if (!LastPiece) 2721 LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R); 2722 assert(LastPiece); 2723 PD.setEndOfPath(LastPiece); 2724 } 2725 2726 // Make sure we get a clean location context map so we don't 2727 // hold onto old mappings. 2728 LCM.clear(); 2729 2730 switch (ActiveScheme) { 2731 case PathDiagnosticConsumer::AlternateExtensive: 2732 GenerateAlternateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 2733 break; 2734 case PathDiagnosticConsumer::Extensive: 2735 GenerateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 2736 break; 2737 case PathDiagnosticConsumer::Minimal: 2738 GenerateMinimalPathDiagnostic(PD, PDB, N, LCM, visitors); 2739 break; 2740 case PathDiagnosticConsumer::None: 2741 GenerateVisitorsOnlyPathDiagnostic(PD, PDB, N, visitors); 2742 break; 2743 } 2744 2745 // Clean up the visitors we used. 2746 llvm::DeleteContainerPointers(visitors); 2747 2748 // Did anything change while generating this path? 2749 finalReportConfigToken = R->getConfigurationChangeToken(); 2750 } while (finalReportConfigToken != origReportConfigToken); 2751 2752 if (!R->isValid()) 2753 continue; 2754 2755 // Finally, prune the diagnostic path of uninteresting stuff. 2756 if (!PD.path.empty()) { 2757 // Remove messages that are basically the same. 2758 removeRedundantMsgs(PD.getMutablePieces()); 2759 2760 if (R->shouldPrunePath() && 2761 getEngine().getAnalysisManager().options.shouldPrunePaths()) { 2762 bool stillHasNotes = removeUnneededCalls(PD.getMutablePieces(), R, LCM); 2763 assert(stillHasNotes); 2764 (void)stillHasNotes; 2765 } 2766 2767 adjustCallLocations(PD.getMutablePieces()); 2768 2769 if (ActiveScheme == PathDiagnosticConsumer::AlternateExtensive) { 2770 SourceManager &SM = getSourceManager(); 2771 2772 // Reduce the number of edges from a very conservative set 2773 // to an aesthetically pleasing subset that conveys the 2774 // necessary information. 2775 OptimizedCallsSet OCS; 2776 while (optimizeEdges(PD.getMutablePieces(), SM, OCS, LCM)) {} 2777 2778 // Adjust edges into loop conditions to make them more uniform 2779 // and aesthetically pleasing. 2780 adjustLoopEdges(PD.getMutablePieces(), LCM, SM); 2781 } 2782 } 2783 2784 // We found a report and didn't suppress it. 2785 return true; 2786 } 2787 2788 // We suppressed all the reports in this equivalence class. 2789 assert(!HasInvalid && "Inconsistent suppression"); 2790 (void)HasInvalid; 2791 return false; 2792} 2793 2794void BugReporter::Register(BugType *BT) { 2795 BugTypes = F.add(BugTypes, BT); 2796} 2797 2798void BugReporter::emitReport(BugReport* R) { 2799 // Compute the bug report's hash to determine its equivalence class. 2800 llvm::FoldingSetNodeID ID; 2801 R->Profile(ID); 2802 2803 // Lookup the equivance class. If there isn't one, create it. 2804 BugType& BT = R->getBugType(); 2805 Register(&BT); 2806 void *InsertPos; 2807 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos); 2808 2809 if (!EQ) { 2810 EQ = new BugReportEquivClass(R); 2811 EQClasses.InsertNode(EQ, InsertPos); 2812 EQClassesVector.push_back(EQ); 2813 } 2814 else 2815 EQ->AddReport(R); 2816} 2817 2818 2819//===----------------------------------------------------------------------===// 2820// Emitting reports in equivalence classes. 2821//===----------------------------------------------------------------------===// 2822 2823namespace { 2824struct FRIEC_WLItem { 2825 const ExplodedNode *N; 2826 ExplodedNode::const_succ_iterator I, E; 2827 2828 FRIEC_WLItem(const ExplodedNode *n) 2829 : N(n), I(N->succ_begin()), E(N->succ_end()) {} 2830}; 2831} 2832 2833static BugReport * 2834FindReportInEquivalenceClass(BugReportEquivClass& EQ, 2835 SmallVectorImpl<BugReport*> &bugReports) { 2836 2837 BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end(); 2838 assert(I != E); 2839 BugType& BT = I->getBugType(); 2840 2841 // If we don't need to suppress any of the nodes because they are 2842 // post-dominated by a sink, simply add all the nodes in the equivalence class 2843 // to 'Nodes'. Any of the reports will serve as a "representative" report. 2844 if (!BT.isSuppressOnSink()) { 2845 BugReport *R = I; 2846 for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) { 2847 const ExplodedNode *N = I->getErrorNode(); 2848 if (N) { 2849 R = I; 2850 bugReports.push_back(R); 2851 } 2852 } 2853 return R; 2854 } 2855 2856 // For bug reports that should be suppressed when all paths are post-dominated 2857 // by a sink node, iterate through the reports in the equivalence class 2858 // until we find one that isn't post-dominated (if one exists). We use a 2859 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write 2860 // this as a recursive function, but we don't want to risk blowing out the 2861 // stack for very long paths. 2862 BugReport *exampleReport = 0; 2863 2864 for (; I != E; ++I) { 2865 const ExplodedNode *errorNode = I->getErrorNode(); 2866 2867 if (!errorNode) 2868 continue; 2869 if (errorNode->isSink()) { 2870 llvm_unreachable( 2871 "BugType::isSuppressSink() should not be 'true' for sink end nodes"); 2872 } 2873 // No successors? By definition this nodes isn't post-dominated by a sink. 2874 if (errorNode->succ_empty()) { 2875 bugReports.push_back(I); 2876 if (!exampleReport) 2877 exampleReport = I; 2878 continue; 2879 } 2880 2881 // At this point we know that 'N' is not a sink and it has at least one 2882 // successor. Use a DFS worklist to find a non-sink end-of-path node. 2883 typedef FRIEC_WLItem WLItem; 2884 typedef SmallVector<WLItem, 10> DFSWorkList; 2885 llvm::DenseMap<const ExplodedNode *, unsigned> Visited; 2886 2887 DFSWorkList WL; 2888 WL.push_back(errorNode); 2889 Visited[errorNode] = 1; 2890 2891 while (!WL.empty()) { 2892 WLItem &WI = WL.back(); 2893 assert(!WI.N->succ_empty()); 2894 2895 for (; WI.I != WI.E; ++WI.I) { 2896 const ExplodedNode *Succ = *WI.I; 2897 // End-of-path node? 2898 if (Succ->succ_empty()) { 2899 // If we found an end-of-path node that is not a sink. 2900 if (!Succ->isSink()) { 2901 bugReports.push_back(I); 2902 if (!exampleReport) 2903 exampleReport = I; 2904 WL.clear(); 2905 break; 2906 } 2907 // Found a sink? Continue on to the next successor. 2908 continue; 2909 } 2910 // Mark the successor as visited. If it hasn't been explored, 2911 // enqueue it to the DFS worklist. 2912 unsigned &mark = Visited[Succ]; 2913 if (!mark) { 2914 mark = 1; 2915 WL.push_back(Succ); 2916 break; 2917 } 2918 } 2919 2920 // The worklist may have been cleared at this point. First 2921 // check if it is empty before checking the last item. 2922 if (!WL.empty() && &WL.back() == &WI) 2923 WL.pop_back(); 2924 } 2925 } 2926 2927 // ExampleReport will be NULL if all the nodes in the equivalence class 2928 // were post-dominated by sinks. 2929 return exampleReport; 2930} 2931 2932void BugReporter::FlushReport(BugReportEquivClass& EQ) { 2933 SmallVector<BugReport*, 10> bugReports; 2934 BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports); 2935 if (exampleReport) { 2936 const PathDiagnosticConsumers &C = getPathDiagnosticConsumers(); 2937 for (PathDiagnosticConsumers::const_iterator I=C.begin(), 2938 E=C.end(); I != E; ++I) { 2939 FlushReport(exampleReport, **I, bugReports); 2940 } 2941 } 2942} 2943 2944void BugReporter::FlushReport(BugReport *exampleReport, 2945 PathDiagnosticConsumer &PD, 2946 ArrayRef<BugReport*> bugReports) { 2947 2948 // FIXME: Make sure we use the 'R' for the path that was actually used. 2949 // Probably doesn't make a difference in practice. 2950 BugType& BT = exampleReport->getBugType(); 2951 2952 OwningPtr<PathDiagnostic> 2953 D(new PathDiagnostic(exampleReport->getDeclWithIssue(), 2954 exampleReport->getBugType().getName(), 2955 exampleReport->getDescription(), 2956 exampleReport->getShortDescription(/*Fallback=*/false), 2957 BT.getCategory(), 2958 exampleReport->getUniqueingLocation(), 2959 exampleReport->getUniqueingDecl())); 2960 2961 MaxBugClassSize = std::max(bugReports.size(), 2962 static_cast<size_t>(MaxBugClassSize)); 2963 2964 // Generate the full path diagnostic, using the generation scheme 2965 // specified by the PathDiagnosticConsumer. Note that we have to generate 2966 // path diagnostics even for consumers which do not support paths, because 2967 // the BugReporterVisitors may mark this bug as a false positive. 2968 if (!bugReports.empty()) 2969 if (!generatePathDiagnostic(*D.get(), PD, bugReports)) 2970 return; 2971 2972 MaxValidBugClassSize = std::max(bugReports.size(), 2973 static_cast<size_t>(MaxValidBugClassSize)); 2974 2975 // If the path is empty, generate a single step path with the location 2976 // of the issue. 2977 if (D->path.empty()) { 2978 PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager()); 2979 PathDiagnosticPiece *piece = 2980 new PathDiagnosticEventPiece(L, exampleReport->getDescription()); 2981 BugReport::ranges_iterator Beg, End; 2982 llvm::tie(Beg, End) = exampleReport->getRanges(); 2983 for ( ; Beg != End; ++Beg) 2984 piece->addRange(*Beg); 2985 D->setEndOfPath(piece); 2986 } 2987 2988 // Get the meta data. 2989 const BugReport::ExtraTextList &Meta = exampleReport->getExtraText(); 2990 for (BugReport::ExtraTextList::const_iterator i = Meta.begin(), 2991 e = Meta.end(); i != e; ++i) { 2992 D->addMeta(*i); 2993 } 2994 2995 PD.HandlePathDiagnostic(D.take()); 2996} 2997 2998void BugReporter::EmitBasicReport(const Decl *DeclWithIssue, 2999 StringRef name, 3000 StringRef category, 3001 StringRef str, PathDiagnosticLocation Loc, 3002 SourceRange* RBeg, unsigned NumRanges) { 3003 3004 // 'BT' is owned by BugReporter. 3005 BugType *BT = getBugTypeForName(name, category); 3006 BugReport *R = new BugReport(*BT, str, Loc); 3007 R->setDeclWithIssue(DeclWithIssue); 3008 for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg); 3009 emitReport(R); 3010} 3011 3012BugType *BugReporter::getBugTypeForName(StringRef name, 3013 StringRef category) { 3014 SmallString<136> fullDesc; 3015 llvm::raw_svector_ostream(fullDesc) << name << ":" << category; 3016 llvm::StringMapEntry<BugType *> & 3017 entry = StrBugTypes.GetOrCreateValue(fullDesc); 3018 BugType *BT = entry.getValue(); 3019 if (!BT) { 3020 BT = new BugType(name, category); 3021 entry.setValue(BT); 3022 } 3023 return BT; 3024} 3025