BugReporter.cpp revision af84f8fea486dde096466e85f4bca7c8d3ff4571
1// BugReporter.cpp - Generate PathDiagnostics for Bugs ------------*- C++ -*--// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines BugReporter, a utility class for generating 11// PathDiagnostics. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/StaticAnalyzer/Core/BugReporter/BugReporter.h" 16#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" 17#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h" 18#include "clang/AST/ASTContext.h" 19#include "clang/Analysis/CFG.h" 20#include "clang/AST/DeclObjC.h" 21#include "clang/AST/Expr.h" 22#include "clang/AST/ParentMap.h" 23#include "clang/AST/StmtObjC.h" 24#include "clang/Basic/SourceManager.h" 25#include "clang/Analysis/ProgramPoint.h" 26#include "clang/StaticAnalyzer/Core/BugReporter/PathDiagnostic.h" 27#include "llvm/Support/raw_ostream.h" 28#include "llvm/ADT/DenseMap.h" 29#include "llvm/ADT/SmallString.h" 30#include "llvm/ADT/STLExtras.h" 31#include "llvm/ADT/OwningPtr.h" 32#include "llvm/ADT/IntrusiveRefCntPtr.h" 33#include <queue> 34 35using namespace clang; 36using namespace ento; 37 38BugReporterVisitor::~BugReporterVisitor() {} 39 40void BugReporterContext::anchor() {} 41 42//===----------------------------------------------------------------------===// 43// Helper routines for walking the ExplodedGraph and fetching statements. 44//===----------------------------------------------------------------------===// 45 46static inline const Stmt *GetStmt(const ProgramPoint &P) { 47 if (const StmtPoint* SP = dyn_cast<StmtPoint>(&P)) 48 return SP->getStmt(); 49 else if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) 50 return BE->getSrc()->getTerminator(); 51 52 return 0; 53} 54 55static inline const ExplodedNode* 56GetPredecessorNode(const ExplodedNode *N) { 57 return N->pred_empty() ? NULL : *(N->pred_begin()); 58} 59 60static inline const ExplodedNode* 61GetSuccessorNode(const ExplodedNode *N) { 62 return N->succ_empty() ? NULL : *(N->succ_begin()); 63} 64 65static const Stmt *GetPreviousStmt(const ExplodedNode *N) { 66 for (N = GetPredecessorNode(N); N; N = GetPredecessorNode(N)) 67 if (const Stmt *S = GetStmt(N->getLocation())) 68 return S; 69 70 return 0; 71} 72 73static const Stmt *GetNextStmt(const ExplodedNode *N) { 74 for (N = GetSuccessorNode(N); N; N = GetSuccessorNode(N)) 75 if (const Stmt *S = GetStmt(N->getLocation())) { 76 // Check if the statement is '?' or '&&'/'||'. These are "merges", 77 // not actual statement points. 78 switch (S->getStmtClass()) { 79 case Stmt::ChooseExprClass: 80 case Stmt::BinaryConditionalOperatorClass: continue; 81 case Stmt::ConditionalOperatorClass: continue; 82 case Stmt::BinaryOperatorClass: { 83 BinaryOperatorKind Op = cast<BinaryOperator>(S)->getOpcode(); 84 if (Op == BO_LAnd || Op == BO_LOr) 85 continue; 86 break; 87 } 88 default: 89 break; 90 } 91 return S; 92 } 93 94 return 0; 95} 96 97static inline const Stmt* 98GetCurrentOrPreviousStmt(const ExplodedNode *N) { 99 if (const Stmt *S = GetStmt(N->getLocation())) 100 return S; 101 102 return GetPreviousStmt(N); 103} 104 105static inline const Stmt* 106GetCurrentOrNextStmt(const ExplodedNode *N) { 107 if (const Stmt *S = GetStmt(N->getLocation())) 108 return S; 109 110 return GetNextStmt(N); 111} 112 113//===----------------------------------------------------------------------===// 114// PathDiagnosticBuilder and its associated routines and helper objects. 115//===----------------------------------------------------------------------===// 116 117typedef llvm::DenseMap<const ExplodedNode*, 118const ExplodedNode*> NodeBackMap; 119 120namespace { 121class NodeMapClosure : public BugReport::NodeResolver { 122 NodeBackMap& M; 123public: 124 NodeMapClosure(NodeBackMap *m) : M(*m) {} 125 ~NodeMapClosure() {} 126 127 const ExplodedNode *getOriginalNode(const ExplodedNode *N) { 128 NodeBackMap::iterator I = M.find(N); 129 return I == M.end() ? 0 : I->second; 130 } 131}; 132 133class PathDiagnosticBuilder : public BugReporterContext { 134 BugReport *R; 135 PathDiagnosticConsumer *PDC; 136 OwningPtr<ParentMap> PM; 137 NodeMapClosure NMC; 138public: 139 PathDiagnosticBuilder(GRBugReporter &br, 140 BugReport *r, NodeBackMap *Backmap, 141 PathDiagnosticConsumer *pdc) 142 : BugReporterContext(br), 143 R(r), PDC(pdc), NMC(Backmap) {} 144 145 PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N); 146 147 PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os, 148 const ExplodedNode *N); 149 150 BugReport *getBugReport() { return R; } 151 152 Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); } 153 154 const LocationContext* getLocationContext() { 155 return R->getErrorNode()->getLocationContext(); 156 } 157 158 ParentMap& getParentMap() { return R->getErrorNode()->getParentMap(); } 159 160 const Stmt *getParent(const Stmt *S) { 161 return getParentMap().getParent(S); 162 } 163 164 virtual NodeMapClosure& getNodeResolver() { return NMC; } 165 166 PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S); 167 168 PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const { 169 return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive; 170 } 171 172 bool supportsLogicalOpControlFlow() const { 173 return PDC ? PDC->supportsLogicalOpControlFlow() : true; 174 } 175}; 176} // end anonymous namespace 177 178PathDiagnosticLocation 179PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) { 180 if (const Stmt *S = GetNextStmt(N)) 181 return PathDiagnosticLocation(S, getSourceManager(), getLocationContext()); 182 183 return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(), 184 getSourceManager()); 185} 186 187PathDiagnosticLocation 188PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os, 189 const ExplodedNode *N) { 190 191 // Slow, but probably doesn't matter. 192 if (os.str().empty()) 193 os << ' '; 194 195 const PathDiagnosticLocation &Loc = ExecutionContinues(N); 196 197 if (Loc.asStmt()) 198 os << "Execution continues on line " 199 << getSourceManager().getExpansionLineNumber(Loc.asLocation()) 200 << '.'; 201 else { 202 os << "Execution jumps to the end of the "; 203 const Decl *D = N->getLocationContext()->getDecl(); 204 if (isa<ObjCMethodDecl>(D)) 205 os << "method"; 206 else if (isa<FunctionDecl>(D)) 207 os << "function"; 208 else { 209 assert(isa<BlockDecl>(D)); 210 os << "anonymous block"; 211 } 212 os << '.'; 213 } 214 215 return Loc; 216} 217 218static bool IsNested(const Stmt *S, ParentMap &PM) { 219 if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S))) 220 return true; 221 222 const Stmt *Parent = PM.getParentIgnoreParens(S); 223 224 if (Parent) 225 switch (Parent->getStmtClass()) { 226 case Stmt::ForStmtClass: 227 case Stmt::DoStmtClass: 228 case Stmt::WhileStmtClass: 229 return true; 230 default: 231 break; 232 } 233 234 return false; 235} 236 237PathDiagnosticLocation 238PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) { 239 assert(S && "Null Stmt *passed to getEnclosingStmtLocation"); 240 ParentMap &P = getParentMap(); 241 SourceManager &SMgr = getSourceManager(); 242 const LocationContext *LC = getLocationContext(); 243 244 while (IsNested(S, P)) { 245 const Stmt *Parent = P.getParentIgnoreParens(S); 246 247 if (!Parent) 248 break; 249 250 switch (Parent->getStmtClass()) { 251 case Stmt::BinaryOperatorClass: { 252 const BinaryOperator *B = cast<BinaryOperator>(Parent); 253 if (B->isLogicalOp()) 254 return PathDiagnosticLocation(S, SMgr, LC); 255 break; 256 } 257 case Stmt::CompoundStmtClass: 258 case Stmt::StmtExprClass: 259 return PathDiagnosticLocation(S, SMgr, LC); 260 case Stmt::ChooseExprClass: 261 // Similar to '?' if we are referring to condition, just have the edge 262 // point to the entire choose expression. 263 if (cast<ChooseExpr>(Parent)->getCond() == S) 264 return PathDiagnosticLocation(Parent, SMgr, LC); 265 else 266 return PathDiagnosticLocation(S, SMgr, LC); 267 case Stmt::BinaryConditionalOperatorClass: 268 case Stmt::ConditionalOperatorClass: 269 // For '?', if we are referring to condition, just have the edge point 270 // to the entire '?' expression. 271 if (cast<AbstractConditionalOperator>(Parent)->getCond() == S) 272 return PathDiagnosticLocation(Parent, SMgr, LC); 273 else 274 return PathDiagnosticLocation(S, SMgr, LC); 275 case Stmt::DoStmtClass: 276 return PathDiagnosticLocation(S, SMgr, LC); 277 case Stmt::ForStmtClass: 278 if (cast<ForStmt>(Parent)->getBody() == S) 279 return PathDiagnosticLocation(S, SMgr, LC); 280 break; 281 case Stmt::IfStmtClass: 282 if (cast<IfStmt>(Parent)->getCond() != S) 283 return PathDiagnosticLocation(S, SMgr, LC); 284 break; 285 case Stmt::ObjCForCollectionStmtClass: 286 if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S) 287 return PathDiagnosticLocation(S, SMgr, LC); 288 break; 289 case Stmt::WhileStmtClass: 290 if (cast<WhileStmt>(Parent)->getCond() != S) 291 return PathDiagnosticLocation(S, SMgr, LC); 292 break; 293 default: 294 break; 295 } 296 297 S = Parent; 298 } 299 300 assert(S && "Cannot have null Stmt for PathDiagnosticLocation"); 301 302 // Special case: DeclStmts can appear in for statement declarations, in which 303 // case the ForStmt is the context. 304 if (isa<DeclStmt>(S)) { 305 if (const Stmt *Parent = P.getParent(S)) { 306 switch (Parent->getStmtClass()) { 307 case Stmt::ForStmtClass: 308 case Stmt::ObjCForCollectionStmtClass: 309 return PathDiagnosticLocation(Parent, SMgr, LC); 310 default: 311 break; 312 } 313 } 314 } 315 else if (isa<BinaryOperator>(S)) { 316 // Special case: the binary operator represents the initialization 317 // code in a for statement (this can happen when the variable being 318 // initialized is an old variable. 319 if (const ForStmt *FS = 320 dyn_cast_or_null<ForStmt>(P.getParentIgnoreParens(S))) { 321 if (FS->getInit() == S) 322 return PathDiagnosticLocation(FS, SMgr, LC); 323 } 324 } 325 326 return PathDiagnosticLocation(S, SMgr, LC); 327} 328 329//===----------------------------------------------------------------------===// 330// ScanNotableSymbols: closure-like callback for scanning Store bindings. 331//===----------------------------------------------------------------------===// 332 333static const VarDecl* GetMostRecentVarDeclBinding(const ExplodedNode *N, 334 ProgramStateManager& VMgr, 335 SVal X) { 336 337 for ( ; N ; N = N->pred_empty() ? 0 : *N->pred_begin()) { 338 339 ProgramPoint P = N->getLocation(); 340 341 if (!isa<PostStmt>(P)) 342 continue; 343 344 const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(cast<PostStmt>(P).getStmt()); 345 346 if (!DR) 347 continue; 348 349 SVal Y = N->getState()->getSVal(DR, N->getLocationContext()); 350 351 if (X != Y) 352 continue; 353 354 const VarDecl *VD = dyn_cast<VarDecl>(DR->getDecl()); 355 356 if (!VD) 357 continue; 358 359 return VD; 360 } 361 362 return 0; 363} 364 365namespace { 366class NotableSymbolHandler 367: public StoreManager::BindingsHandler { 368 369 SymbolRef Sym; 370 ProgramStateRef PrevSt; 371 const Stmt *S; 372 ProgramStateManager& VMgr; 373 const ExplodedNode *Pred; 374 PathDiagnostic& PD; 375 BugReporter& BR; 376 377public: 378 379 NotableSymbolHandler(SymbolRef sym, 380 ProgramStateRef prevst, 381 const Stmt *s, 382 ProgramStateManager& vmgr, 383 const ExplodedNode *pred, 384 PathDiagnostic& pd, 385 BugReporter& br) 386 : Sym(sym), 387 PrevSt(prevst), 388 S(s), 389 VMgr(vmgr), 390 Pred(pred), 391 PD(pd), 392 BR(br) {} 393 394 bool HandleBinding(StoreManager& SMgr, Store store, const MemRegion* R, 395 SVal V) { 396 397 SymbolRef ScanSym = V.getAsSymbol(); 398 399 if (ScanSym != Sym) 400 return true; 401 402 // Check if the previous state has this binding. 403 SVal X = PrevSt->getSVal(loc::MemRegionVal(R)); 404 405 if (X == V) // Same binding? 406 return true; 407 408 // Different binding. Only handle assignments for now. We don't pull 409 // this check out of the loop because we will eventually handle other 410 // cases. 411 412 VarDecl *VD = 0; 413 414 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 415 if (!B->isAssignmentOp()) 416 return true; 417 418 // What variable did we assign to? 419 DeclRefExpr *DR = dyn_cast<DeclRefExpr>(B->getLHS()->IgnoreParenCasts()); 420 421 if (!DR) 422 return true; 423 424 VD = dyn_cast<VarDecl>(DR->getDecl()); 425 } 426 else if (const DeclStmt *DS = dyn_cast<DeclStmt>(S)) { 427 // FIXME: Eventually CFGs won't have DeclStmts. Right now we 428 // assume that each DeclStmt has a single Decl. This invariant 429 // holds by construction in the CFG. 430 VD = dyn_cast<VarDecl>(*DS->decl_begin()); 431 } 432 433 if (!VD) 434 return true; 435 436 // What is the most recently referenced variable with this binding? 437 const VarDecl *MostRecent = GetMostRecentVarDeclBinding(Pred, VMgr, V); 438 439 if (!MostRecent) 440 return true; 441 442 // Create the diagnostic. 443 if (Loc::isLocType(VD->getType())) { 444 SmallString<64> buf; 445 llvm::raw_svector_ostream os(buf); 446 os << '\'' << *VD << "' now aliases '" << *MostRecent << '\''; 447 PathDiagnosticLocation L = 448 PathDiagnosticLocation::createBegin(S, BR.getSourceManager(), 449 Pred->getLocationContext()); 450 PD.path.push_front(new PathDiagnosticEventPiece(L, os.str())); 451 } 452 453 return true; 454 } 455}; 456} 457 458static void HandleNotableSymbol(const ExplodedNode *N, 459 const Stmt *S, 460 SymbolRef Sym, BugReporter& BR, 461 PathDiagnostic& PD) { 462 463 const ExplodedNode *Pred = N->pred_empty() ? 0 : *N->pred_begin(); 464 ProgramStateRef PrevSt = Pred ? Pred->getState() : 0; 465 466 if (!PrevSt) 467 return; 468 469 // Look at the region bindings of the current state that map to the 470 // specified symbol. Are any of them not in the previous state? 471 ProgramStateManager& VMgr = cast<GRBugReporter>(BR).getStateManager(); 472 NotableSymbolHandler H(Sym, PrevSt, S, VMgr, Pred, PD, BR); 473 cast<GRBugReporter>(BR).getStateManager().iterBindings(N->getState(), H); 474} 475 476namespace { 477class ScanNotableSymbols 478: public StoreManager::BindingsHandler { 479 480 llvm::SmallSet<SymbolRef, 10> AlreadyProcessed; 481 const ExplodedNode *N; 482 const Stmt *S; 483 GRBugReporter& BR; 484 PathDiagnostic& PD; 485 486public: 487 ScanNotableSymbols(const ExplodedNode *n, const Stmt *s, 488 GRBugReporter& br, PathDiagnostic& pd) 489 : N(n), S(s), BR(br), PD(pd) {} 490 491 bool HandleBinding(StoreManager& SMgr, Store store, 492 const MemRegion* R, SVal V) { 493 494 SymbolRef ScanSym = V.getAsSymbol(); 495 496 if (!ScanSym) 497 return true; 498 499 if (!BR.isNotable(ScanSym)) 500 return true; 501 502 if (AlreadyProcessed.count(ScanSym)) 503 return true; 504 505 AlreadyProcessed.insert(ScanSym); 506 507 HandleNotableSymbol(N, S, ScanSym, BR, PD); 508 return true; 509 } 510}; 511} // end anonymous namespace 512 513//===----------------------------------------------------------------------===// 514// "Minimal" path diagnostic generation algorithm. 515//===----------------------------------------------------------------------===// 516 517static void CompactPathDiagnostic(PathDiagnostic &PD, const SourceManager& SM); 518 519static void GenerateMinimalPathDiagnostic(PathDiagnostic& PD, 520 PathDiagnosticBuilder &PDB, 521 const ExplodedNode *N) { 522 523 SourceManager& SMgr = PDB.getSourceManager(); 524 const LocationContext *LC = PDB.getLocationContext(); 525 const ExplodedNode *NextNode = N->pred_empty() 526 ? NULL : *(N->pred_begin()); 527 while (NextNode) { 528 N = NextNode; 529 NextNode = GetPredecessorNode(N); 530 531 ProgramPoint P = N->getLocation(); 532 533 if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) { 534 const CFGBlock *Src = BE->getSrc(); 535 const CFGBlock *Dst = BE->getDst(); 536 const Stmt *T = Src->getTerminator(); 537 538 if (!T) 539 continue; 540 541 PathDiagnosticLocation Start = 542 PathDiagnosticLocation::createBegin(T, SMgr, 543 N->getLocationContext()); 544 545 switch (T->getStmtClass()) { 546 default: 547 break; 548 549 case Stmt::GotoStmtClass: 550 case Stmt::IndirectGotoStmtClass: { 551 const Stmt *S = GetNextStmt(N); 552 553 if (!S) 554 continue; 555 556 std::string sbuf; 557 llvm::raw_string_ostream os(sbuf); 558 const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S); 559 560 os << "Control jumps to line " 561 << End.asLocation().getExpansionLineNumber(); 562 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 563 os.str())); 564 break; 565 } 566 567 case Stmt::SwitchStmtClass: { 568 // Figure out what case arm we took. 569 std::string sbuf; 570 llvm::raw_string_ostream os(sbuf); 571 572 if (const Stmt *S = Dst->getLabel()) { 573 PathDiagnosticLocation End(S, SMgr, LC); 574 575 switch (S->getStmtClass()) { 576 default: 577 os << "No cases match in the switch statement. " 578 "Control jumps to line " 579 << End.asLocation().getExpansionLineNumber(); 580 break; 581 case Stmt::DefaultStmtClass: 582 os << "Control jumps to the 'default' case at line " 583 << End.asLocation().getExpansionLineNumber(); 584 break; 585 586 case Stmt::CaseStmtClass: { 587 os << "Control jumps to 'case "; 588 const CaseStmt *Case = cast<CaseStmt>(S); 589 const Expr *LHS = Case->getLHS()->IgnoreParenCasts(); 590 591 // Determine if it is an enum. 592 bool GetRawInt = true; 593 594 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) { 595 // FIXME: Maybe this should be an assertion. Are there cases 596 // were it is not an EnumConstantDecl? 597 const EnumConstantDecl *D = 598 dyn_cast<EnumConstantDecl>(DR->getDecl()); 599 600 if (D) { 601 GetRawInt = false; 602 os << *D; 603 } 604 } 605 606 if (GetRawInt) 607 os << LHS->EvaluateKnownConstInt(PDB.getASTContext()); 608 609 os << ":' at line " 610 << End.asLocation().getExpansionLineNumber(); 611 break; 612 } 613 } 614 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 615 os.str())); 616 } 617 else { 618 os << "'Default' branch taken. "; 619 const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N); 620 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 621 os.str())); 622 } 623 624 break; 625 } 626 627 case Stmt::BreakStmtClass: 628 case Stmt::ContinueStmtClass: { 629 std::string sbuf; 630 llvm::raw_string_ostream os(sbuf); 631 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 632 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 633 os.str())); 634 break; 635 } 636 637 // Determine control-flow for ternary '?'. 638 case Stmt::BinaryConditionalOperatorClass: 639 case Stmt::ConditionalOperatorClass: { 640 std::string sbuf; 641 llvm::raw_string_ostream os(sbuf); 642 os << "'?' condition is "; 643 644 if (*(Src->succ_begin()+1) == Dst) 645 os << "false"; 646 else 647 os << "true"; 648 649 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 650 651 if (const Stmt *S = End.asStmt()) 652 End = PDB.getEnclosingStmtLocation(S); 653 654 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 655 os.str())); 656 break; 657 } 658 659 // Determine control-flow for short-circuited '&&' and '||'. 660 case Stmt::BinaryOperatorClass: { 661 if (!PDB.supportsLogicalOpControlFlow()) 662 break; 663 664 const BinaryOperator *B = cast<BinaryOperator>(T); 665 std::string sbuf; 666 llvm::raw_string_ostream os(sbuf); 667 os << "Left side of '"; 668 669 if (B->getOpcode() == BO_LAnd) { 670 os << "&&" << "' is "; 671 672 if (*(Src->succ_begin()+1) == Dst) { 673 os << "false"; 674 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 675 PathDiagnosticLocation Start = 676 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 677 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 678 os.str())); 679 } 680 else { 681 os << "true"; 682 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 683 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 684 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 685 os.str())); 686 } 687 } 688 else { 689 assert(B->getOpcode() == BO_LOr); 690 os << "||" << "' is "; 691 692 if (*(Src->succ_begin()+1) == Dst) { 693 os << "false"; 694 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 695 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 696 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 697 os.str())); 698 } 699 else { 700 os << "true"; 701 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 702 PathDiagnosticLocation Start = 703 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 704 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 705 os.str())); 706 } 707 } 708 709 break; 710 } 711 712 case Stmt::DoStmtClass: { 713 if (*(Src->succ_begin()) == Dst) { 714 std::string sbuf; 715 llvm::raw_string_ostream os(sbuf); 716 717 os << "Loop condition is true. "; 718 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 719 720 if (const Stmt *S = End.asStmt()) 721 End = PDB.getEnclosingStmtLocation(S); 722 723 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 724 os.str())); 725 } 726 else { 727 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 728 729 if (const Stmt *S = End.asStmt()) 730 End = PDB.getEnclosingStmtLocation(S); 731 732 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 733 "Loop condition is false. Exiting loop")); 734 } 735 736 break; 737 } 738 739 case Stmt::WhileStmtClass: 740 case Stmt::ForStmtClass: { 741 if (*(Src->succ_begin()+1) == Dst) { 742 std::string sbuf; 743 llvm::raw_string_ostream os(sbuf); 744 745 os << "Loop condition is false. "; 746 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 747 if (const Stmt *S = End.asStmt()) 748 End = PDB.getEnclosingStmtLocation(S); 749 750 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 751 os.str())); 752 } 753 else { 754 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 755 if (const Stmt *S = End.asStmt()) 756 End = PDB.getEnclosingStmtLocation(S); 757 758 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 759 "Loop condition is true. Entering loop body")); 760 } 761 762 break; 763 } 764 765 case Stmt::IfStmtClass: { 766 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 767 768 if (const Stmt *S = End.asStmt()) 769 End = PDB.getEnclosingStmtLocation(S); 770 771 if (*(Src->succ_begin()+1) == Dst) 772 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 773 "Taking false branch")); 774 else 775 PD.path.push_front(new PathDiagnosticControlFlowPiece(Start, End, 776 "Taking true branch")); 777 778 break; 779 } 780 } 781 } 782 783 if (NextNode) { 784 // Add diagnostic pieces from custom visitors. 785 BugReport *R = PDB.getBugReport(); 786 for (BugReport::visitor_iterator I = R->visitor_begin(), 787 E = R->visitor_end(); I!=E; ++I) { 788 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) 789 PD.path.push_front(p); 790 } 791 } 792 793 if (const PostStmt *PS = dyn_cast<PostStmt>(&P)) { 794 // Scan the region bindings, and see if a "notable" symbol has a new 795 // lval binding. 796 ScanNotableSymbols SNS(N, PS->getStmt(), PDB.getBugReporter(), PD); 797 PDB.getStateManager().iterBindings(N->getState(), SNS); 798 } 799 } 800 801 // After constructing the full PathDiagnostic, do a pass over it to compact 802 // PathDiagnosticPieces that occur within a macro. 803 CompactPathDiagnostic(PD, PDB.getSourceManager()); 804} 805 806//===----------------------------------------------------------------------===// 807// "Extensive" PathDiagnostic generation. 808//===----------------------------------------------------------------------===// 809 810static bool IsControlFlowExpr(const Stmt *S) { 811 const Expr *E = dyn_cast<Expr>(S); 812 813 if (!E) 814 return false; 815 816 E = E->IgnoreParenCasts(); 817 818 if (isa<AbstractConditionalOperator>(E)) 819 return true; 820 821 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E)) 822 if (B->isLogicalOp()) 823 return true; 824 825 return false; 826} 827 828namespace { 829class ContextLocation : public PathDiagnosticLocation { 830 bool IsDead; 831public: 832 ContextLocation(const PathDiagnosticLocation &L, bool isdead = false) 833 : PathDiagnosticLocation(L), IsDead(isdead) {} 834 835 void markDead() { IsDead = true; } 836 bool isDead() const { return IsDead; } 837}; 838 839class EdgeBuilder { 840 std::vector<ContextLocation> CLocs; 841 typedef std::vector<ContextLocation>::iterator iterator; 842 PathDiagnostic &PD; 843 PathDiagnosticBuilder &PDB; 844 PathDiagnosticLocation PrevLoc; 845 846 bool IsConsumedExpr(const PathDiagnosticLocation &L); 847 848 bool containsLocation(const PathDiagnosticLocation &Container, 849 const PathDiagnosticLocation &Containee); 850 851 PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L); 852 853 PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L, 854 bool firstCharOnly = false) { 855 if (const Stmt *S = L.asStmt()) { 856 const Stmt *Original = S; 857 while (1) { 858 // Adjust the location for some expressions that are best referenced 859 // by one of their subexpressions. 860 switch (S->getStmtClass()) { 861 default: 862 break; 863 case Stmt::ParenExprClass: 864 case Stmt::GenericSelectionExprClass: 865 S = cast<Expr>(S)->IgnoreParens(); 866 firstCharOnly = true; 867 continue; 868 case Stmt::BinaryConditionalOperatorClass: 869 case Stmt::ConditionalOperatorClass: 870 S = cast<AbstractConditionalOperator>(S)->getCond(); 871 firstCharOnly = true; 872 continue; 873 case Stmt::ChooseExprClass: 874 S = cast<ChooseExpr>(S)->getCond(); 875 firstCharOnly = true; 876 continue; 877 case Stmt::BinaryOperatorClass: 878 S = cast<BinaryOperator>(S)->getLHS(); 879 firstCharOnly = true; 880 continue; 881 } 882 883 break; 884 } 885 886 if (S != Original) 887 L = PathDiagnosticLocation(S, L.getManager(), PDB.getLocationContext()); 888 } 889 890 if (firstCharOnly) 891 L = PathDiagnosticLocation::createSingleLocation(L); 892 893 return L; 894 } 895 896 void popLocation() { 897 if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) { 898 // For contexts, we only one the first character as the range. 899 rawAddEdge(cleanUpLocation(CLocs.back(), true)); 900 } 901 CLocs.pop_back(); 902 } 903 904public: 905 EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb) 906 : PD(pd), PDB(pdb) { 907 908 // If the PathDiagnostic already has pieces, add the enclosing statement 909 // of the first piece as a context as well. 910 if (!PD.path.empty()) { 911 PrevLoc = (*PD.path.begin())->getLocation(); 912 913 if (const Stmt *S = PrevLoc.asStmt()) 914 addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 915 } 916 } 917 918 ~EdgeBuilder() { 919 while (!CLocs.empty()) popLocation(); 920 921 // Finally, add an initial edge from the start location of the first 922 // statement (if it doesn't already exist). 923 PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin( 924 PDB.getLocationContext(), 925 PDB.getSourceManager()); 926 if (L.isValid()) 927 rawAddEdge(L); 928 } 929 930 void flushLocations() { 931 while (!CLocs.empty()) 932 popLocation(); 933 PrevLoc = PathDiagnosticLocation(); 934 } 935 936 void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false); 937 938 void rawAddEdge(PathDiagnosticLocation NewLoc); 939 940 void addContext(const Stmt *S); 941 void addExtendedContext(const Stmt *S); 942}; 943} // end anonymous namespace 944 945 946PathDiagnosticLocation 947EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) { 948 if (const Stmt *S = L.asStmt()) { 949 if (IsControlFlowExpr(S)) 950 return L; 951 952 return PDB.getEnclosingStmtLocation(S); 953 } 954 955 return L; 956} 957 958bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container, 959 const PathDiagnosticLocation &Containee) { 960 961 if (Container == Containee) 962 return true; 963 964 if (Container.asDecl()) 965 return true; 966 967 if (const Stmt *S = Containee.asStmt()) 968 if (const Stmt *ContainerS = Container.asStmt()) { 969 while (S) { 970 if (S == ContainerS) 971 return true; 972 S = PDB.getParent(S); 973 } 974 return false; 975 } 976 977 // Less accurate: compare using source ranges. 978 SourceRange ContainerR = Container.asRange(); 979 SourceRange ContaineeR = Containee.asRange(); 980 981 SourceManager &SM = PDB.getSourceManager(); 982 SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin()); 983 SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd()); 984 SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin()); 985 SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd()); 986 987 unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg); 988 unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd); 989 unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg); 990 unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd); 991 992 assert(ContainerBegLine <= ContainerEndLine); 993 assert(ContaineeBegLine <= ContaineeEndLine); 994 995 return (ContainerBegLine <= ContaineeBegLine && 996 ContainerEndLine >= ContaineeEndLine && 997 (ContainerBegLine != ContaineeBegLine || 998 SM.getExpansionColumnNumber(ContainerRBeg) <= 999 SM.getExpansionColumnNumber(ContaineeRBeg)) && 1000 (ContainerEndLine != ContaineeEndLine || 1001 SM.getExpansionColumnNumber(ContainerREnd) >= 1002 SM.getExpansionColumnNumber(ContainerREnd))); 1003} 1004 1005void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) { 1006 if (!PrevLoc.isValid()) { 1007 PrevLoc = NewLoc; 1008 return; 1009 } 1010 1011 const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc); 1012 const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc); 1013 1014 if (NewLocClean.asLocation() == PrevLocClean.asLocation()) 1015 return; 1016 1017 // FIXME: Ignore intra-macro edges for now. 1018 if (NewLocClean.asLocation().getExpansionLoc() == 1019 PrevLocClean.asLocation().getExpansionLoc()) 1020 return; 1021 1022 PD.path.push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean)); 1023 PrevLoc = NewLoc; 1024} 1025 1026void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd) { 1027 1028 if (!alwaysAdd && NewLoc.asLocation().isMacroID()) 1029 return; 1030 1031 const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc); 1032 1033 while (!CLocs.empty()) { 1034 ContextLocation &TopContextLoc = CLocs.back(); 1035 1036 // Is the top location context the same as the one for the new location? 1037 if (TopContextLoc == CLoc) { 1038 if (alwaysAdd) { 1039 if (IsConsumedExpr(TopContextLoc) && 1040 !IsControlFlowExpr(TopContextLoc.asStmt())) 1041 TopContextLoc.markDead(); 1042 1043 rawAddEdge(NewLoc); 1044 } 1045 1046 return; 1047 } 1048 1049 if (containsLocation(TopContextLoc, CLoc)) { 1050 if (alwaysAdd) { 1051 rawAddEdge(NewLoc); 1052 1053 if (IsConsumedExpr(CLoc) && !IsControlFlowExpr(CLoc.asStmt())) { 1054 CLocs.push_back(ContextLocation(CLoc, true)); 1055 return; 1056 } 1057 } 1058 1059 CLocs.push_back(CLoc); 1060 return; 1061 } 1062 1063 // Context does not contain the location. Flush it. 1064 popLocation(); 1065 } 1066 1067 // If we reach here, there is no enclosing context. Just add the edge. 1068 rawAddEdge(NewLoc); 1069} 1070 1071bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) { 1072 if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt())) 1073 return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X); 1074 1075 return false; 1076} 1077 1078void EdgeBuilder::addExtendedContext(const Stmt *S) { 1079 if (!S) 1080 return; 1081 1082 const Stmt *Parent = PDB.getParent(S); 1083 while (Parent) { 1084 if (isa<CompoundStmt>(Parent)) 1085 Parent = PDB.getParent(Parent); 1086 else 1087 break; 1088 } 1089 1090 if (Parent) { 1091 switch (Parent->getStmtClass()) { 1092 case Stmt::DoStmtClass: 1093 case Stmt::ObjCAtSynchronizedStmtClass: 1094 addContext(Parent); 1095 default: 1096 break; 1097 } 1098 } 1099 1100 addContext(S); 1101} 1102 1103void EdgeBuilder::addContext(const Stmt *S) { 1104 if (!S) 1105 return; 1106 1107 PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.getLocationContext()); 1108 1109 while (!CLocs.empty()) { 1110 const PathDiagnosticLocation &TopContextLoc = CLocs.back(); 1111 1112 // Is the top location context the same as the one for the new location? 1113 if (TopContextLoc == L) 1114 return; 1115 1116 if (containsLocation(TopContextLoc, L)) { 1117 CLocs.push_back(L); 1118 return; 1119 } 1120 1121 // Context does not contain the location. Flush it. 1122 popLocation(); 1123 } 1124 1125 CLocs.push_back(L); 1126} 1127 1128static void GenerateExtensivePathDiagnostic(PathDiagnostic& PD, 1129 PathDiagnosticBuilder &PDB, 1130 const ExplodedNode *N) { 1131 EdgeBuilder EB(PD, PDB); 1132 const SourceManager& SM = PDB.getSourceManager(); 1133 1134 const ExplodedNode *NextNode = N->pred_empty() ? NULL : *(N->pred_begin()); 1135 while (NextNode) { 1136 N = NextNode; 1137 NextNode = GetPredecessorNode(N); 1138 ProgramPoint P = N->getLocation(); 1139 1140 do { 1141 if (const CallExit *CE = dyn_cast<CallExit>(&P)) { 1142 const StackFrameContext *LCtx = 1143 CE->getLocationContext()->getCurrentStackFrame(); 1144 PathDiagnosticLocation Loc(LCtx->getCallSite(), 1145 PDB.getSourceManager(), 1146 LCtx); 1147 EB.addEdge(Loc, true); 1148 EB.flushLocations(); 1149 break; 1150 } 1151 1152 // Was the predecessor in a different stack frame? 1153 if (NextNode && 1154 !isa<CallExit>(NextNode->getLocation()) && 1155 NextNode->getLocationContext()->getCurrentStackFrame() != 1156 N->getLocationContext()->getCurrentStackFrame()) { 1157 EB.flushLocations(); 1158 } 1159 1160 // Block edges. 1161 if (const BlockEdge *BE = dyn_cast<BlockEdge>(&P)) { 1162 const CFGBlock &Blk = *BE->getSrc(); 1163 const Stmt *Term = Blk.getTerminator(); 1164 1165 // Are we jumping to the head of a loop? Add a special diagnostic. 1166 if (const Stmt *Loop = BE->getDst()->getLoopTarget()) { 1167 PathDiagnosticLocation L(Loop, SM, PDB.getLocationContext()); 1168 const CompoundStmt *CS = NULL; 1169 1170 if (!Term) { 1171 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1172 CS = dyn_cast<CompoundStmt>(FS->getBody()); 1173 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1174 CS = dyn_cast<CompoundStmt>(WS->getBody()); 1175 } 1176 1177 PathDiagnosticEventPiece *p = 1178 new PathDiagnosticEventPiece(L, 1179 "Looping back to the head of the loop"); 1180 1181 EB.addEdge(p->getLocation(), true); 1182 PD.path.push_front(p); 1183 1184 if (CS) { 1185 PathDiagnosticLocation BL = 1186 PathDiagnosticLocation::createEndBrace(CS, SM); 1187 EB.addEdge(BL); 1188 } 1189 } 1190 1191 if (Term) 1192 EB.addContext(Term); 1193 1194 break; 1195 } 1196 1197 if (const BlockEntrance *BE = dyn_cast<BlockEntrance>(&P)) { 1198 if (const CFGStmt *S = BE->getFirstElement().getAs<CFGStmt>()) { 1199 const Stmt *stmt = S->getStmt(); 1200 if (IsControlFlowExpr(stmt)) { 1201 // Add the proper context for '&&', '||', and '?'. 1202 EB.addContext(stmt); 1203 } 1204 else 1205 EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt()); 1206 } 1207 1208 break; 1209 } 1210 1211 1212 } while (0); 1213 1214 if (!NextNode) 1215 continue; 1216 1217 // Add pieces from custom visitors. 1218 BugReport *R = PDB.getBugReport(); 1219 for (BugReport::visitor_iterator I = R->visitor_begin(), 1220 E = R->visitor_end(); I!=E; ++I) { 1221 if (PathDiagnosticPiece *p = (*I)->VisitNode(N, NextNode, PDB, *R)) { 1222 const PathDiagnosticLocation &Loc = p->getLocation(); 1223 EB.addEdge(Loc, true); 1224 PD.path.push_front(p); 1225 if (const Stmt *S = Loc.asStmt()) 1226 EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 1227 } 1228 } 1229 } 1230} 1231 1232//===----------------------------------------------------------------------===// 1233// Methods for BugType and subclasses. 1234//===----------------------------------------------------------------------===// 1235BugType::~BugType() { } 1236 1237void BugType::FlushReports(BugReporter &BR) {} 1238 1239void BuiltinBug::anchor() {} 1240 1241//===----------------------------------------------------------------------===// 1242// Methods for BugReport and subclasses. 1243//===----------------------------------------------------------------------===// 1244 1245void BugReport::NodeResolver::anchor() {} 1246 1247void BugReport::addVisitor(BugReporterVisitor* visitor) { 1248 if (!visitor) 1249 return; 1250 1251 llvm::FoldingSetNodeID ID; 1252 visitor->Profile(ID); 1253 void *InsertPos; 1254 1255 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) { 1256 delete visitor; 1257 return; 1258 } 1259 1260 CallbacksSet.InsertNode(visitor, InsertPos); 1261 Callbacks = F.add(visitor, Callbacks); 1262} 1263 1264BugReport::~BugReport() { 1265 for (visitor_iterator I = visitor_begin(), E = visitor_end(); I != E; ++I) { 1266 delete *I; 1267 } 1268} 1269 1270void BugReport::Profile(llvm::FoldingSetNodeID& hash) const { 1271 hash.AddPointer(&BT); 1272 hash.AddString(Description); 1273 if (Location.isValid()) { 1274 Location.Profile(hash); 1275 } else { 1276 assert(ErrorNode); 1277 hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode)); 1278 } 1279 1280 for (SmallVectorImpl<SourceRange>::const_iterator I = 1281 Ranges.begin(), E = Ranges.end(); I != E; ++I) { 1282 const SourceRange range = *I; 1283 if (!range.isValid()) 1284 continue; 1285 hash.AddInteger(range.getBegin().getRawEncoding()); 1286 hash.AddInteger(range.getEnd().getRawEncoding()); 1287 } 1288} 1289 1290const Stmt *BugReport::getStmt() const { 1291 if (!ErrorNode) 1292 return 0; 1293 1294 ProgramPoint ProgP = ErrorNode->getLocation(); 1295 const Stmt *S = NULL; 1296 1297 if (BlockEntrance *BE = dyn_cast<BlockEntrance>(&ProgP)) { 1298 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit(); 1299 if (BE->getBlock() == &Exit) 1300 S = GetPreviousStmt(ErrorNode); 1301 } 1302 if (!S) 1303 S = GetStmt(ProgP); 1304 1305 return S; 1306} 1307 1308std::pair<BugReport::ranges_iterator, BugReport::ranges_iterator> 1309BugReport::getRanges() { 1310 // If no custom ranges, add the range of the statement corresponding to 1311 // the error node. 1312 if (Ranges.empty()) { 1313 if (const Expr *E = dyn_cast_or_null<Expr>(getStmt())) 1314 addRange(E->getSourceRange()); 1315 else 1316 return std::make_pair(ranges_iterator(), ranges_iterator()); 1317 } 1318 1319 // User-specified absence of range info. 1320 if (Ranges.size() == 1 && !Ranges.begin()->isValid()) 1321 return std::make_pair(ranges_iterator(), ranges_iterator()); 1322 1323 return std::make_pair(Ranges.begin(), Ranges.end()); 1324} 1325 1326PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const { 1327 if (ErrorNode) { 1328 assert(!Location.isValid() && 1329 "Either Location or ErrorNode should be specified but not both."); 1330 1331 if (const Stmt *S = GetCurrentOrPreviousStmt(ErrorNode)) { 1332 const LocationContext *LC = ErrorNode->getLocationContext(); 1333 1334 // For member expressions, return the location of the '.' or '->'. 1335 if (const MemberExpr *ME = dyn_cast<MemberExpr>(S)) 1336 return PathDiagnosticLocation::createMemberLoc(ME, SM); 1337 // For binary operators, return the location of the operator. 1338 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(S)) 1339 return PathDiagnosticLocation::createOperatorLoc(B, SM); 1340 1341 return PathDiagnosticLocation::createBegin(S, SM, LC); 1342 } 1343 } else { 1344 assert(Location.isValid()); 1345 return Location; 1346 } 1347 1348 return PathDiagnosticLocation(); 1349} 1350 1351//===----------------------------------------------------------------------===// 1352// Methods for BugReporter and subclasses. 1353//===----------------------------------------------------------------------===// 1354 1355BugReportEquivClass::~BugReportEquivClass() { 1356 for (iterator I=begin(), E=end(); I!=E; ++I) delete *I; 1357} 1358 1359GRBugReporter::~GRBugReporter() { } 1360BugReporterData::~BugReporterData() {} 1361 1362ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); } 1363 1364ProgramStateManager& 1365GRBugReporter::getStateManager() { return Eng.getStateManager(); } 1366 1367BugReporter::~BugReporter() { 1368 FlushReports(); 1369 1370 // Free the bug reports we are tracking. 1371 typedef std::vector<BugReportEquivClass *> ContTy; 1372 for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end(); 1373 I != E; ++I) { 1374 delete *I; 1375 } 1376} 1377 1378void BugReporter::FlushReports() { 1379 if (BugTypes.isEmpty()) 1380 return; 1381 1382 // First flush the warnings for each BugType. This may end up creating new 1383 // warnings and new BugTypes. 1384 // FIXME: Only NSErrorChecker needs BugType's FlushReports. 1385 // Turn NSErrorChecker into a proper checker and remove this. 1386 SmallVector<const BugType*, 16> bugTypes; 1387 for (BugTypesTy::iterator I=BugTypes.begin(), E=BugTypes.end(); I!=E; ++I) 1388 bugTypes.push_back(*I); 1389 for (SmallVector<const BugType*, 16>::iterator 1390 I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I) 1391 const_cast<BugType*>(*I)->FlushReports(*this); 1392 1393 typedef llvm::FoldingSet<BugReportEquivClass> SetTy; 1394 for (SetTy::iterator EI=EQClasses.begin(), EE=EQClasses.end(); EI!=EE;++EI){ 1395 BugReportEquivClass& EQ = *EI; 1396 FlushReport(EQ); 1397 } 1398 1399 // BugReporter owns and deletes only BugTypes created implicitly through 1400 // EmitBasicReport. 1401 // FIXME: There are leaks from checkers that assume that the BugTypes they 1402 // create will be destroyed by the BugReporter. 1403 for (llvm::StringMap<BugType*>::iterator 1404 I = StrBugTypes.begin(), E = StrBugTypes.end(); I != E; ++I) 1405 delete I->second; 1406 1407 // Remove all references to the BugType objects. 1408 BugTypes = F.getEmptySet(); 1409} 1410 1411//===----------------------------------------------------------------------===// 1412// PathDiagnostics generation. 1413//===----------------------------------------------------------------------===// 1414 1415static std::pair<std::pair<ExplodedGraph*, NodeBackMap*>, 1416 std::pair<ExplodedNode*, unsigned> > 1417MakeReportGraph(const ExplodedGraph* G, 1418 SmallVectorImpl<const ExplodedNode*> &nodes) { 1419 1420 // Create the trimmed graph. It will contain the shortest paths from the 1421 // error nodes to the root. In the new graph we should only have one 1422 // error node unless there are two or more error nodes with the same minimum 1423 // path length. 1424 ExplodedGraph* GTrim; 1425 InterExplodedGraphMap* NMap; 1426 1427 llvm::DenseMap<const void*, const void*> InverseMap; 1428 llvm::tie(GTrim, NMap) = G->Trim(nodes.data(), nodes.data() + nodes.size(), 1429 &InverseMap); 1430 1431 // Create owning pointers for GTrim and NMap just to ensure that they are 1432 // released when this function exists. 1433 OwningPtr<ExplodedGraph> AutoReleaseGTrim(GTrim); 1434 OwningPtr<InterExplodedGraphMap> AutoReleaseNMap(NMap); 1435 1436 // Find the (first) error node in the trimmed graph. We just need to consult 1437 // the node map (NMap) which maps from nodes in the original graph to nodes 1438 // in the new graph. 1439 1440 std::queue<const ExplodedNode*> WS; 1441 typedef llvm::DenseMap<const ExplodedNode*, unsigned> IndexMapTy; 1442 IndexMapTy IndexMap; 1443 1444 for (unsigned nodeIndex = 0 ; nodeIndex < nodes.size(); ++nodeIndex) { 1445 const ExplodedNode *originalNode = nodes[nodeIndex]; 1446 if (const ExplodedNode *N = NMap->getMappedNode(originalNode)) { 1447 WS.push(N); 1448 IndexMap[originalNode] = nodeIndex; 1449 } 1450 } 1451 1452 assert(!WS.empty() && "No error node found in the trimmed graph."); 1453 1454 // Create a new (third!) graph with a single path. This is the graph 1455 // that will be returned to the caller. 1456 ExplodedGraph *GNew = new ExplodedGraph(); 1457 1458 // Sometimes the trimmed graph can contain a cycle. Perform a reverse BFS 1459 // to the root node, and then construct a new graph that contains only 1460 // a single path. 1461 llvm::DenseMap<const void*,unsigned> Visited; 1462 1463 unsigned cnt = 0; 1464 const ExplodedNode *Root = 0; 1465 1466 while (!WS.empty()) { 1467 const ExplodedNode *Node = WS.front(); 1468 WS.pop(); 1469 1470 if (Visited.find(Node) != Visited.end()) 1471 continue; 1472 1473 Visited[Node] = cnt++; 1474 1475 if (Node->pred_empty()) { 1476 Root = Node; 1477 break; 1478 } 1479 1480 for (ExplodedNode::const_pred_iterator I=Node->pred_begin(), 1481 E=Node->pred_end(); I!=E; ++I) 1482 WS.push(*I); 1483 } 1484 1485 assert(Root); 1486 1487 // Now walk from the root down the BFS path, always taking the successor 1488 // with the lowest number. 1489 ExplodedNode *Last = 0, *First = 0; 1490 NodeBackMap *BM = new NodeBackMap(); 1491 unsigned NodeIndex = 0; 1492 1493 for ( const ExplodedNode *N = Root ;;) { 1494 // Lookup the number associated with the current node. 1495 llvm::DenseMap<const void*,unsigned>::iterator I = Visited.find(N); 1496 assert(I != Visited.end()); 1497 1498 // Create the equivalent node in the new graph with the same state 1499 // and location. 1500 ExplodedNode *NewN = GNew->getNode(N->getLocation(), N->getState()); 1501 1502 // Store the mapping to the original node. 1503 llvm::DenseMap<const void*, const void*>::iterator IMitr=InverseMap.find(N); 1504 assert(IMitr != InverseMap.end() && "No mapping to original node."); 1505 (*BM)[NewN] = (const ExplodedNode*) IMitr->second; 1506 1507 // Link up the new node with the previous node. 1508 if (Last) 1509 NewN->addPredecessor(Last, *GNew); 1510 1511 Last = NewN; 1512 1513 // Are we at the final node? 1514 IndexMapTy::iterator IMI = 1515 IndexMap.find((const ExplodedNode*)(IMitr->second)); 1516 if (IMI != IndexMap.end()) { 1517 First = NewN; 1518 NodeIndex = IMI->second; 1519 break; 1520 } 1521 1522 // Find the next successor node. We choose the node that is marked 1523 // with the lowest DFS number. 1524 ExplodedNode::const_succ_iterator SI = N->succ_begin(); 1525 ExplodedNode::const_succ_iterator SE = N->succ_end(); 1526 N = 0; 1527 1528 for (unsigned MinVal = 0; SI != SE; ++SI) { 1529 1530 I = Visited.find(*SI); 1531 1532 if (I == Visited.end()) 1533 continue; 1534 1535 if (!N || I->second < MinVal) { 1536 N = *SI; 1537 MinVal = I->second; 1538 } 1539 } 1540 1541 assert(N); 1542 } 1543 1544 assert(First); 1545 1546 return std::make_pair(std::make_pair(GNew, BM), 1547 std::make_pair(First, NodeIndex)); 1548} 1549 1550/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object 1551/// and collapses PathDiagosticPieces that are expanded by macros. 1552static void CompactPathDiagnostic(PathDiagnostic &PD, const SourceManager& SM) { 1553 typedef std::vector<std::pair<llvm::IntrusiveRefCntPtr<PathDiagnosticMacroPiece>, SourceLocation> > 1554 MacroStackTy; 1555 1556 typedef std::vector<llvm::IntrusiveRefCntPtr<PathDiagnosticPiece> > 1557 PiecesTy; 1558 1559 MacroStackTy MacroStack; 1560 PiecesTy Pieces; 1561 1562 for (PathPieces::iterator I = PD.path.begin(), E = PD.path.end(); I!=E; ++I) { 1563 // Get the location of the PathDiagnosticPiece. 1564 const FullSourceLoc Loc = (*I)->getLocation().asLocation(); 1565 1566 // Determine the instantiation location, which is the location we group 1567 // related PathDiagnosticPieces. 1568 SourceLocation InstantiationLoc = Loc.isMacroID() ? 1569 SM.getExpansionLoc(Loc) : 1570 SourceLocation(); 1571 1572 if (Loc.isFileID()) { 1573 MacroStack.clear(); 1574 Pieces.push_back(*I); 1575 continue; 1576 } 1577 1578 assert(Loc.isMacroID()); 1579 1580 // Is the PathDiagnosticPiece within the same macro group? 1581 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) { 1582 MacroStack.back().first->subPieces.push_back(*I); 1583 continue; 1584 } 1585 1586 // We aren't in the same group. Are we descending into a new macro 1587 // or are part of an old one? 1588 llvm::IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup; 1589 1590 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ? 1591 SM.getExpansionLoc(Loc) : 1592 SourceLocation(); 1593 1594 // Walk the entire macro stack. 1595 while (!MacroStack.empty()) { 1596 if (InstantiationLoc == MacroStack.back().second) { 1597 MacroGroup = MacroStack.back().first; 1598 break; 1599 } 1600 1601 if (ParentInstantiationLoc == MacroStack.back().second) { 1602 MacroGroup = MacroStack.back().first; 1603 break; 1604 } 1605 1606 MacroStack.pop_back(); 1607 } 1608 1609 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) { 1610 // Create a new macro group and add it to the stack. 1611 PathDiagnosticMacroPiece *NewGroup = 1612 new PathDiagnosticMacroPiece( 1613 PathDiagnosticLocation::createSingleLocation((*I)->getLocation())); 1614 1615 if (MacroGroup) 1616 MacroGroup->subPieces.push_back(NewGroup); 1617 else { 1618 assert(InstantiationLoc.isFileID()); 1619 Pieces.push_back(NewGroup); 1620 } 1621 1622 MacroGroup = NewGroup; 1623 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc)); 1624 } 1625 1626 // Finally, add the PathDiagnosticPiece to the group. 1627 MacroGroup->subPieces.push_back(*I); 1628 } 1629 1630 // Now take the pieces and construct a new PathDiagnostic. 1631 PD.path.clear(); 1632 1633 for (PiecesTy::iterator I=Pieces.begin(), E=Pieces.end(); I!=E; ++I) { 1634 if (PathDiagnosticMacroPiece *MP = dyn_cast<PathDiagnosticMacroPiece>(*I)) 1635 if (!MP->containsEvent()) 1636 continue; 1637 PD.path.push_back(*I); 1638 } 1639} 1640 1641void GRBugReporter::GeneratePathDiagnostic(PathDiagnostic& PD, 1642 SmallVectorImpl<BugReport *> &bugReports) { 1643 1644 assert(!bugReports.empty()); 1645 SmallVector<const ExplodedNode *, 10> errorNodes; 1646 for (SmallVectorImpl<BugReport*>::iterator I = bugReports.begin(), 1647 E = bugReports.end(); I != E; ++I) { 1648 errorNodes.push_back((*I)->getErrorNode()); 1649 } 1650 1651 // Construct a new graph that contains only a single path from the error 1652 // node to a root. 1653 const std::pair<std::pair<ExplodedGraph*, NodeBackMap*>, 1654 std::pair<ExplodedNode*, unsigned> >& 1655 GPair = MakeReportGraph(&getGraph(), errorNodes); 1656 1657 // Find the BugReport with the original location. 1658 assert(GPair.second.second < bugReports.size()); 1659 BugReport *R = bugReports[GPair.second.second]; 1660 assert(R && "No original report found for sliced graph."); 1661 1662 OwningPtr<ExplodedGraph> ReportGraph(GPair.first.first); 1663 OwningPtr<NodeBackMap> BackMap(GPair.first.second); 1664 const ExplodedNode *N = GPair.second.first; 1665 1666 // Start building the path diagnostic... 1667 PathDiagnosticBuilder PDB(*this, R, BackMap.get(), 1668 getPathDiagnosticConsumer()); 1669 1670 // Register additional node visitors. 1671 R->addVisitor(new NilReceiverBRVisitor()); 1672 R->addVisitor(new ConditionBRVisitor()); 1673 1674 // If inlining is turning out, emit diagnostics for CallEnter and 1675 // CallExit at the top level. 1676 bool showTopLevel = Eng.getAnalysisManager().shouldInlineCall(); 1677 R->addVisitor(new CallEnterExitBRVisitor(showTopLevel)); 1678 1679 // Generate the very last diagnostic piece - the piece is visible before 1680 // the trace is expanded. 1681 PathDiagnosticPiece *LastPiece = 0; 1682 for (BugReport::visitor_iterator I = R->visitor_begin(), 1683 E = R->visitor_end(); I!=E; ++I) { 1684 if (PathDiagnosticPiece *Piece = (*I)->getEndPath(PDB, N, *R)) { 1685 assert (!LastPiece && 1686 "There can only be one final piece in a diagnostic."); 1687 LastPiece = Piece; 1688 } 1689 } 1690 if (!LastPiece) 1691 LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R); 1692 if (LastPiece) 1693 PD.path.push_back(LastPiece); 1694 else 1695 return; 1696 1697 switch (PDB.getGenerationScheme()) { 1698 case PathDiagnosticConsumer::Extensive: 1699 GenerateExtensivePathDiagnostic(PD, PDB, N); 1700 break; 1701 case PathDiagnosticConsumer::Minimal: 1702 GenerateMinimalPathDiagnostic(PD, PDB, N); 1703 break; 1704 } 1705} 1706 1707void BugReporter::Register(BugType *BT) { 1708 BugTypes = F.add(BugTypes, BT); 1709} 1710 1711void BugReporter::EmitReport(BugReport* R) { 1712 // Compute the bug report's hash to determine its equivalence class. 1713 llvm::FoldingSetNodeID ID; 1714 R->Profile(ID); 1715 1716 // Lookup the equivance class. If there isn't one, create it. 1717 BugType& BT = R->getBugType(); 1718 Register(&BT); 1719 void *InsertPos; 1720 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos); 1721 1722 if (!EQ) { 1723 EQ = new BugReportEquivClass(R); 1724 EQClasses.InsertNode(EQ, InsertPos); 1725 EQClassesVector.push_back(EQ); 1726 } 1727 else 1728 EQ->AddReport(R); 1729} 1730 1731 1732//===----------------------------------------------------------------------===// 1733// Emitting reports in equivalence classes. 1734//===----------------------------------------------------------------------===// 1735 1736namespace { 1737struct FRIEC_WLItem { 1738 const ExplodedNode *N; 1739 ExplodedNode::const_succ_iterator I, E; 1740 1741 FRIEC_WLItem(const ExplodedNode *n) 1742 : N(n), I(N->succ_begin()), E(N->succ_end()) {} 1743}; 1744} 1745 1746static BugReport * 1747FindReportInEquivalenceClass(BugReportEquivClass& EQ, 1748 SmallVectorImpl<BugReport*> &bugReports) { 1749 1750 BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end(); 1751 assert(I != E); 1752 BugReport *R = *I; 1753 BugType& BT = R->getBugType(); 1754 1755 // If we don't need to suppress any of the nodes because they are 1756 // post-dominated by a sink, simply add all the nodes in the equivalence class 1757 // to 'Nodes'. Any of the reports will serve as a "representative" report. 1758 if (!BT.isSuppressOnSink()) { 1759 for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) { 1760 const ExplodedNode *N = I->getErrorNode(); 1761 if (N) { 1762 R = *I; 1763 bugReports.push_back(R); 1764 } 1765 } 1766 return R; 1767 } 1768 1769 // For bug reports that should be suppressed when all paths are post-dominated 1770 // by a sink node, iterate through the reports in the equivalence class 1771 // until we find one that isn't post-dominated (if one exists). We use a 1772 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write 1773 // this as a recursive function, but we don't want to risk blowing out the 1774 // stack for very long paths. 1775 BugReport *exampleReport = 0; 1776 1777 for (; I != E; ++I) { 1778 R = *I; 1779 const ExplodedNode *errorNode = R->getErrorNode(); 1780 1781 if (!errorNode) 1782 continue; 1783 if (errorNode->isSink()) { 1784 llvm_unreachable( 1785 "BugType::isSuppressSink() should not be 'true' for sink end nodes"); 1786 } 1787 // No successors? By definition this nodes isn't post-dominated by a sink. 1788 if (errorNode->succ_empty()) { 1789 bugReports.push_back(R); 1790 if (!exampleReport) 1791 exampleReport = R; 1792 continue; 1793 } 1794 1795 // At this point we know that 'N' is not a sink and it has at least one 1796 // successor. Use a DFS worklist to find a non-sink end-of-path node. 1797 typedef FRIEC_WLItem WLItem; 1798 typedef SmallVector<WLItem, 10> DFSWorkList; 1799 llvm::DenseMap<const ExplodedNode *, unsigned> Visited; 1800 1801 DFSWorkList WL; 1802 WL.push_back(errorNode); 1803 Visited[errorNode] = 1; 1804 1805 while (!WL.empty()) { 1806 WLItem &WI = WL.back(); 1807 assert(!WI.N->succ_empty()); 1808 1809 for (; WI.I != WI.E; ++WI.I) { 1810 const ExplodedNode *Succ = *WI.I; 1811 // End-of-path node? 1812 if (Succ->succ_empty()) { 1813 // If we found an end-of-path node that is not a sink. 1814 if (!Succ->isSink()) { 1815 bugReports.push_back(R); 1816 if (!exampleReport) 1817 exampleReport = R; 1818 WL.clear(); 1819 break; 1820 } 1821 // Found a sink? Continue on to the next successor. 1822 continue; 1823 } 1824 // Mark the successor as visited. If it hasn't been explored, 1825 // enqueue it to the DFS worklist. 1826 unsigned &mark = Visited[Succ]; 1827 if (!mark) { 1828 mark = 1; 1829 WL.push_back(Succ); 1830 break; 1831 } 1832 } 1833 1834 // The worklist may have been cleared at this point. First 1835 // check if it is empty before checking the last item. 1836 if (!WL.empty() && &WL.back() == &WI) 1837 WL.pop_back(); 1838 } 1839 } 1840 1841 // ExampleReport will be NULL if all the nodes in the equivalence class 1842 // were post-dominated by sinks. 1843 return exampleReport; 1844} 1845 1846//===----------------------------------------------------------------------===// 1847// DiagnosticCache. This is a hack to cache analyzer diagnostics. It 1848// uses global state, which eventually should go elsewhere. 1849//===----------------------------------------------------------------------===// 1850namespace { 1851class DiagCacheItem : public llvm::FoldingSetNode { 1852 llvm::FoldingSetNodeID ID; 1853public: 1854 DiagCacheItem(BugReport *R, PathDiagnostic *PD) { 1855 R->Profile(ID); 1856 PD->Profile(ID); 1857 } 1858 1859 void Profile(llvm::FoldingSetNodeID &id) { 1860 id = ID; 1861 } 1862 1863 llvm::FoldingSetNodeID &getID() { return ID; } 1864}; 1865} 1866 1867static bool IsCachedDiagnostic(BugReport *R, PathDiagnostic *PD) { 1868 // FIXME: Eventually this diagnostic cache should reside in something 1869 // like AnalysisManager instead of being a static variable. This is 1870 // really unsafe in the long term. 1871 typedef llvm::FoldingSet<DiagCacheItem> DiagnosticCache; 1872 static DiagnosticCache DC; 1873 1874 void *InsertPos; 1875 DiagCacheItem *Item = new DiagCacheItem(R, PD); 1876 1877 if (DC.FindNodeOrInsertPos(Item->getID(), InsertPos)) { 1878 delete Item; 1879 return true; 1880 } 1881 1882 DC.InsertNode(Item, InsertPos); 1883 return false; 1884} 1885 1886void BugReporter::FlushReport(BugReportEquivClass& EQ) { 1887 SmallVector<BugReport*, 10> bugReports; 1888 BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports); 1889 if (!exampleReport) 1890 return; 1891 1892 PathDiagnosticConsumer* PD = getPathDiagnosticConsumer(); 1893 1894 // FIXME: Make sure we use the 'R' for the path that was actually used. 1895 // Probably doesn't make a difference in practice. 1896 BugType& BT = exampleReport->getBugType(); 1897 1898 OwningPtr<PathDiagnostic> 1899 D(new PathDiagnostic(exampleReport->getBugType().getName(), 1900 !PD || PD->useVerboseDescription() 1901 ? exampleReport->getDescription() 1902 : exampleReport->getShortDescription(), 1903 BT.getCategory())); 1904 1905 if (!bugReports.empty()) 1906 GeneratePathDiagnostic(*D.get(), bugReports); 1907 1908 if (IsCachedDiagnostic(exampleReport, D.get())) 1909 return; 1910 1911 // Get the meta data. 1912 const BugReport::ExtraTextList &Meta = 1913 exampleReport->getExtraText(); 1914 for (BugReport::ExtraTextList::const_iterator i = Meta.begin(), 1915 e = Meta.end(); i != e; ++i) { 1916 D->addMeta(*i); 1917 } 1918 1919 // Emit a summary diagnostic to the regular Diagnostics engine. 1920 BugReport::ranges_iterator Beg, End; 1921 llvm::tie(Beg, End) = exampleReport->getRanges(); 1922 DiagnosticsEngine &Diag = getDiagnostic(); 1923 1924 // Search the description for '%', as that will be interpretted as a 1925 // format character by FormatDiagnostics. 1926 StringRef desc = exampleReport->getShortDescription(); 1927 unsigned ErrorDiag; 1928 { 1929 SmallString<512> TmpStr; 1930 llvm::raw_svector_ostream Out(TmpStr); 1931 for (StringRef::iterator I=desc.begin(), E=desc.end(); I!=E; ++I) 1932 if (*I == '%') 1933 Out << "%%"; 1934 else 1935 Out << *I; 1936 1937 Out.flush(); 1938 ErrorDiag = Diag.getCustomDiagID(DiagnosticsEngine::Warning, TmpStr); 1939 } 1940 1941 { 1942 DiagnosticBuilder diagBuilder = Diag.Report( 1943 exampleReport->getLocation(getSourceManager()).asLocation(), ErrorDiag); 1944 for (BugReport::ranges_iterator I = Beg; I != End; ++I) 1945 diagBuilder << *I; 1946 } 1947 1948 // Emit a full diagnostic for the path if we have a PathDiagnosticConsumer. 1949 if (!PD) 1950 return; 1951 1952 if (D->path.empty()) { 1953 PathDiagnosticPiece *piece = new PathDiagnosticEventPiece( 1954 exampleReport->getLocation(getSourceManager()), 1955 exampleReport->getDescription()); 1956 1957 for ( ; Beg != End; ++Beg) piece->addRange(*Beg); 1958 D->path.push_back(piece); 1959 } 1960 1961 PD->HandlePathDiagnostic(D.take()); 1962} 1963 1964void BugReporter::EmitBasicReport(StringRef name, StringRef str, 1965 PathDiagnosticLocation Loc, 1966 SourceRange* RBeg, unsigned NumRanges) { 1967 EmitBasicReport(name, "", str, Loc, RBeg, NumRanges); 1968} 1969 1970void BugReporter::EmitBasicReport(StringRef name, 1971 StringRef category, 1972 StringRef str, PathDiagnosticLocation Loc, 1973 SourceRange* RBeg, unsigned NumRanges) { 1974 1975 // 'BT' is owned by BugReporter. 1976 BugType *BT = getBugTypeForName(name, category); 1977 BugReport *R = new BugReport(*BT, str, Loc); 1978 for ( ; NumRanges > 0 ; --NumRanges, ++RBeg) R->addRange(*RBeg); 1979 EmitReport(R); 1980} 1981 1982BugType *BugReporter::getBugTypeForName(StringRef name, 1983 StringRef category) { 1984 SmallString<136> fullDesc; 1985 llvm::raw_svector_ostream(fullDesc) << name << ":" << category; 1986 llvm::StringMapEntry<BugType *> & 1987 entry = StrBugTypes.GetOrCreateValue(fullDesc); 1988 BugType *BT = entry.getValue(); 1989 if (!BT) { 1990 BT = new BugType(name, category); 1991 entry.setValue(BT); 1992 } 1993 return BT; 1994} 1995