BugReporter.cpp revision 288943
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/AST/ASTContext.h" 17#include "clang/AST/DeclObjC.h" 18#include "clang/AST/Expr.h" 19#include "clang/AST/ExprCXX.h" 20#include "clang/AST/ParentMap.h" 21#include "clang/AST/StmtCXX.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/STLExtras.h" 32#include "llvm/ADT/SmallString.h" 33#include "llvm/ADT/Statistic.h" 34#include "llvm/Support/raw_ostream.h" 35#include <memory> 36#include <queue> 37 38using namespace clang; 39using namespace ento; 40 41#define DEBUG_TYPE "BugReporter" 42 43STATISTIC(MaxBugClassSize, 44 "The maximum number of bug reports in the same equivalence class"); 45STATISTIC(MaxValidBugClassSize, 46 "The maximum number of bug reports in the same equivalence class " 47 "where at least one report is valid (not suppressed)"); 48 49BugReporterVisitor::~BugReporterVisitor() {} 50 51void BugReporterContext::anchor() {} 52 53//===----------------------------------------------------------------------===// 54// Helper routines for walking the ExplodedGraph and fetching statements. 55//===----------------------------------------------------------------------===// 56 57static const Stmt *GetPreviousStmt(const ExplodedNode *N) { 58 for (N = N->getFirstPred(); N; N = N->getFirstPred()) 59 if (const Stmt *S = PathDiagnosticLocation::getStmt(N)) 60 return S; 61 62 return nullptr; 63} 64 65static inline const Stmt* 66GetCurrentOrPreviousStmt(const ExplodedNode *N) { 67 if (const Stmt *S = PathDiagnosticLocation::getStmt(N)) 68 return S; 69 70 return GetPreviousStmt(N); 71} 72 73//===----------------------------------------------------------------------===// 74// Diagnostic cleanup. 75//===----------------------------------------------------------------------===// 76 77static PathDiagnosticEventPiece * 78eventsDescribeSameCondition(PathDiagnosticEventPiece *X, 79 PathDiagnosticEventPiece *Y) { 80 // Prefer diagnostics that come from ConditionBRVisitor over 81 // those that came from TrackConstraintBRVisitor. 82 const void *tagPreferred = ConditionBRVisitor::getTag(); 83 const void *tagLesser = TrackConstraintBRVisitor::getTag(); 84 85 if (X->getLocation() != Y->getLocation()) 86 return nullptr; 87 88 if (X->getTag() == tagPreferred && Y->getTag() == tagLesser) 89 return X; 90 91 if (Y->getTag() == tagPreferred && X->getTag() == tagLesser) 92 return Y; 93 94 return nullptr; 95} 96 97/// An optimization pass over PathPieces that removes redundant diagnostics 98/// generated by both ConditionBRVisitor and TrackConstraintBRVisitor. Both 99/// BugReporterVisitors use different methods to generate diagnostics, with 100/// one capable of emitting diagnostics in some cases but not in others. This 101/// can lead to redundant diagnostic pieces at the same point in a path. 102static void removeRedundantMsgs(PathPieces &path) { 103 unsigned N = path.size(); 104 if (N < 2) 105 return; 106 // NOTE: this loop intentionally is not using an iterator. Instead, we 107 // are streaming the path and modifying it in place. This is done by 108 // grabbing the front, processing it, and if we decide to keep it append 109 // it to the end of the path. The entire path is processed in this way. 110 for (unsigned i = 0; i < N; ++i) { 111 IntrusiveRefCntPtr<PathDiagnosticPiece> piece(path.front()); 112 path.pop_front(); 113 114 switch (piece->getKind()) { 115 case clang::ento::PathDiagnosticPiece::Call: 116 removeRedundantMsgs(cast<PathDiagnosticCallPiece>(piece)->path); 117 break; 118 case clang::ento::PathDiagnosticPiece::Macro: 119 removeRedundantMsgs(cast<PathDiagnosticMacroPiece>(piece)->subPieces); 120 break; 121 case clang::ento::PathDiagnosticPiece::ControlFlow: 122 break; 123 case clang::ento::PathDiagnosticPiece::Event: { 124 if (i == N-1) 125 break; 126 127 if (PathDiagnosticEventPiece *nextEvent = 128 dyn_cast<PathDiagnosticEventPiece>(path.front().get())) { 129 PathDiagnosticEventPiece *event = 130 cast<PathDiagnosticEventPiece>(piece); 131 // Check to see if we should keep one of the two pieces. If we 132 // come up with a preference, record which piece to keep, and consume 133 // another piece from the path. 134 if (PathDiagnosticEventPiece *pieceToKeep = 135 eventsDescribeSameCondition(event, nextEvent)) { 136 piece = pieceToKeep; 137 path.pop_front(); 138 ++i; 139 } 140 } 141 break; 142 } 143 } 144 path.push_back(piece); 145 } 146} 147 148/// A map from PathDiagnosticPiece to the LocationContext of the inlined 149/// function call it represents. 150typedef llvm::DenseMap<const PathPieces *, const LocationContext *> 151 LocationContextMap; 152 153/// Recursively scan through a path and prune out calls and macros pieces 154/// that aren't needed. Return true if afterwards the path contains 155/// "interesting stuff" which means it shouldn't be pruned from the parent path. 156static bool removeUnneededCalls(PathPieces &pieces, BugReport *R, 157 LocationContextMap &LCM) { 158 bool containsSomethingInteresting = false; 159 const unsigned N = pieces.size(); 160 161 for (unsigned i = 0 ; i < N ; ++i) { 162 // Remove the front piece from the path. If it is still something we 163 // want to keep once we are done, we will push it back on the end. 164 IntrusiveRefCntPtr<PathDiagnosticPiece> piece(pieces.front()); 165 pieces.pop_front(); 166 167 switch (piece->getKind()) { 168 case PathDiagnosticPiece::Call: { 169 PathDiagnosticCallPiece *call = cast<PathDiagnosticCallPiece>(piece); 170 // Check if the location context is interesting. 171 assert(LCM.count(&call->path)); 172 if (R->isInteresting(LCM[&call->path])) { 173 containsSomethingInteresting = true; 174 break; 175 } 176 177 if (!removeUnneededCalls(call->path, R, LCM)) 178 continue; 179 180 containsSomethingInteresting = true; 181 break; 182 } 183 case PathDiagnosticPiece::Macro: { 184 PathDiagnosticMacroPiece *macro = cast<PathDiagnosticMacroPiece>(piece); 185 if (!removeUnneededCalls(macro->subPieces, R, LCM)) 186 continue; 187 containsSomethingInteresting = true; 188 break; 189 } 190 case PathDiagnosticPiece::Event: { 191 PathDiagnosticEventPiece *event = cast<PathDiagnosticEventPiece>(piece); 192 193 // We never throw away an event, but we do throw it away wholesale 194 // as part of a path if we throw the entire path away. 195 containsSomethingInteresting |= !event->isPrunable(); 196 break; 197 } 198 case PathDiagnosticPiece::ControlFlow: 199 break; 200 } 201 202 pieces.push_back(piece); 203 } 204 205 return containsSomethingInteresting; 206} 207 208/// Returns true if the given decl has been implicitly given a body, either by 209/// the analyzer or by the compiler proper. 210static bool hasImplicitBody(const Decl *D) { 211 assert(D); 212 return D->isImplicit() || !D->hasBody(); 213} 214 215/// Recursively scan through a path and make sure that all call pieces have 216/// valid locations. 217static void 218adjustCallLocations(PathPieces &Pieces, 219 PathDiagnosticLocation *LastCallLocation = nullptr) { 220 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E; ++I) { 221 PathDiagnosticCallPiece *Call = dyn_cast<PathDiagnosticCallPiece>(*I); 222 223 if (!Call) { 224 assert((*I)->getLocation().asLocation().isValid()); 225 continue; 226 } 227 228 if (LastCallLocation) { 229 bool CallerIsImplicit = hasImplicitBody(Call->getCaller()); 230 if (CallerIsImplicit || !Call->callEnter.asLocation().isValid()) 231 Call->callEnter = *LastCallLocation; 232 if (CallerIsImplicit || !Call->callReturn.asLocation().isValid()) 233 Call->callReturn = *LastCallLocation; 234 } 235 236 // Recursively clean out the subclass. Keep this call around if 237 // it contains any informative diagnostics. 238 PathDiagnosticLocation *ThisCallLocation; 239 if (Call->callEnterWithin.asLocation().isValid() && 240 !hasImplicitBody(Call->getCallee())) 241 ThisCallLocation = &Call->callEnterWithin; 242 else 243 ThisCallLocation = &Call->callEnter; 244 245 assert(ThisCallLocation && "Outermost call has an invalid location"); 246 adjustCallLocations(Call->path, ThisCallLocation); 247 } 248} 249 250/// Remove edges in and out of C++ default initializer expressions. These are 251/// for fields that have in-class initializers, as opposed to being initialized 252/// explicitly in a constructor or braced list. 253static void removeEdgesToDefaultInitializers(PathPieces &Pieces) { 254 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) { 255 if (PathDiagnosticCallPiece *C = dyn_cast<PathDiagnosticCallPiece>(*I)) 256 removeEdgesToDefaultInitializers(C->path); 257 258 if (PathDiagnosticMacroPiece *M = dyn_cast<PathDiagnosticMacroPiece>(*I)) 259 removeEdgesToDefaultInitializers(M->subPieces); 260 261 if (PathDiagnosticControlFlowPiece *CF = 262 dyn_cast<PathDiagnosticControlFlowPiece>(*I)) { 263 const Stmt *Start = CF->getStartLocation().asStmt(); 264 const Stmt *End = CF->getEndLocation().asStmt(); 265 if (Start && isa<CXXDefaultInitExpr>(Start)) { 266 I = Pieces.erase(I); 267 continue; 268 } else if (End && isa<CXXDefaultInitExpr>(End)) { 269 PathPieces::iterator Next = std::next(I); 270 if (Next != E) { 271 if (PathDiagnosticControlFlowPiece *NextCF = 272 dyn_cast<PathDiagnosticControlFlowPiece>(*Next)) { 273 NextCF->setStartLocation(CF->getStartLocation()); 274 } 275 } 276 I = Pieces.erase(I); 277 continue; 278 } 279 } 280 281 I++; 282 } 283} 284 285/// Remove all pieces with invalid locations as these cannot be serialized. 286/// We might have pieces with invalid locations as a result of inlining Body 287/// Farm generated functions. 288static void removePiecesWithInvalidLocations(PathPieces &Pieces) { 289 for (PathPieces::iterator I = Pieces.begin(), E = Pieces.end(); I != E;) { 290 if (PathDiagnosticCallPiece *C = dyn_cast<PathDiagnosticCallPiece>(*I)) 291 removePiecesWithInvalidLocations(C->path); 292 293 if (PathDiagnosticMacroPiece *M = dyn_cast<PathDiagnosticMacroPiece>(*I)) 294 removePiecesWithInvalidLocations(M->subPieces); 295 296 if (!(*I)->getLocation().isValid() || 297 !(*I)->getLocation().asLocation().isValid()) { 298 I = Pieces.erase(I); 299 continue; 300 } 301 I++; 302 } 303} 304 305//===----------------------------------------------------------------------===// 306// PathDiagnosticBuilder and its associated routines and helper objects. 307//===----------------------------------------------------------------------===// 308 309namespace { 310class NodeMapClosure : public BugReport::NodeResolver { 311 InterExplodedGraphMap &M; 312public: 313 NodeMapClosure(InterExplodedGraphMap &m) : M(m) {} 314 315 const ExplodedNode *getOriginalNode(const ExplodedNode *N) override { 316 return M.lookup(N); 317 } 318}; 319 320class PathDiagnosticBuilder : public BugReporterContext { 321 BugReport *R; 322 PathDiagnosticConsumer *PDC; 323 NodeMapClosure NMC; 324public: 325 const LocationContext *LC; 326 327 PathDiagnosticBuilder(GRBugReporter &br, 328 BugReport *r, InterExplodedGraphMap &Backmap, 329 PathDiagnosticConsumer *pdc) 330 : BugReporterContext(br), 331 R(r), PDC(pdc), NMC(Backmap), LC(r->getErrorNode()->getLocationContext()) 332 {} 333 334 PathDiagnosticLocation ExecutionContinues(const ExplodedNode *N); 335 336 PathDiagnosticLocation ExecutionContinues(llvm::raw_string_ostream &os, 337 const ExplodedNode *N); 338 339 BugReport *getBugReport() { return R; } 340 341 Decl const &getCodeDecl() { return R->getErrorNode()->getCodeDecl(); } 342 343 ParentMap& getParentMap() { return LC->getParentMap(); } 344 345 const Stmt *getParent(const Stmt *S) { 346 return getParentMap().getParent(S); 347 } 348 349 NodeMapClosure& getNodeResolver() override { return NMC; } 350 351 PathDiagnosticLocation getEnclosingStmtLocation(const Stmt *S); 352 353 PathDiagnosticConsumer::PathGenerationScheme getGenerationScheme() const { 354 return PDC ? PDC->getGenerationScheme() : PathDiagnosticConsumer::Extensive; 355 } 356 357 bool supportsLogicalOpControlFlow() const { 358 return PDC ? PDC->supportsLogicalOpControlFlow() : true; 359 } 360}; 361} // end anonymous namespace 362 363PathDiagnosticLocation 364PathDiagnosticBuilder::ExecutionContinues(const ExplodedNode *N) { 365 if (const Stmt *S = PathDiagnosticLocation::getNextStmt(N)) 366 return PathDiagnosticLocation(S, getSourceManager(), LC); 367 368 return PathDiagnosticLocation::createDeclEnd(N->getLocationContext(), 369 getSourceManager()); 370} 371 372PathDiagnosticLocation 373PathDiagnosticBuilder::ExecutionContinues(llvm::raw_string_ostream &os, 374 const ExplodedNode *N) { 375 376 // Slow, but probably doesn't matter. 377 if (os.str().empty()) 378 os << ' '; 379 380 const PathDiagnosticLocation &Loc = ExecutionContinues(N); 381 382 if (Loc.asStmt()) 383 os << "Execution continues on line " 384 << getSourceManager().getExpansionLineNumber(Loc.asLocation()) 385 << '.'; 386 else { 387 os << "Execution jumps to the end of the "; 388 const Decl *D = N->getLocationContext()->getDecl(); 389 if (isa<ObjCMethodDecl>(D)) 390 os << "method"; 391 else if (isa<FunctionDecl>(D)) 392 os << "function"; 393 else { 394 assert(isa<BlockDecl>(D)); 395 os << "anonymous block"; 396 } 397 os << '.'; 398 } 399 400 return Loc; 401} 402 403static const Stmt *getEnclosingParent(const Stmt *S, const ParentMap &PM) { 404 if (isa<Expr>(S) && PM.isConsumedExpr(cast<Expr>(S))) 405 return PM.getParentIgnoreParens(S); 406 407 const Stmt *Parent = PM.getParentIgnoreParens(S); 408 if (!Parent) 409 return nullptr; 410 411 switch (Parent->getStmtClass()) { 412 case Stmt::ForStmtClass: 413 case Stmt::DoStmtClass: 414 case Stmt::WhileStmtClass: 415 case Stmt::ObjCForCollectionStmtClass: 416 case Stmt::CXXForRangeStmtClass: 417 return Parent; 418 default: 419 break; 420 } 421 422 return nullptr; 423} 424 425static PathDiagnosticLocation 426getEnclosingStmtLocation(const Stmt *S, SourceManager &SMgr, const ParentMap &P, 427 const LocationContext *LC, bool allowNestedContexts) { 428 if (!S) 429 return PathDiagnosticLocation(); 430 431 while (const Stmt *Parent = getEnclosingParent(S, P)) { 432 switch (Parent->getStmtClass()) { 433 case Stmt::BinaryOperatorClass: { 434 const BinaryOperator *B = cast<BinaryOperator>(Parent); 435 if (B->isLogicalOp()) 436 return PathDiagnosticLocation(allowNestedContexts ? B : S, SMgr, LC); 437 break; 438 } 439 case Stmt::CompoundStmtClass: 440 case Stmt::StmtExprClass: 441 return PathDiagnosticLocation(S, SMgr, LC); 442 case Stmt::ChooseExprClass: 443 // Similar to '?' if we are referring to condition, just have the edge 444 // point to the entire choose expression. 445 if (allowNestedContexts || cast<ChooseExpr>(Parent)->getCond() == S) 446 return PathDiagnosticLocation(Parent, SMgr, LC); 447 else 448 return PathDiagnosticLocation(S, SMgr, LC); 449 case Stmt::BinaryConditionalOperatorClass: 450 case Stmt::ConditionalOperatorClass: 451 // For '?', if we are referring to condition, just have the edge point 452 // to the entire '?' expression. 453 if (allowNestedContexts || 454 cast<AbstractConditionalOperator>(Parent)->getCond() == S) 455 return PathDiagnosticLocation(Parent, SMgr, LC); 456 else 457 return PathDiagnosticLocation(S, SMgr, LC); 458 case Stmt::CXXForRangeStmtClass: 459 if (cast<CXXForRangeStmt>(Parent)->getBody() == S) 460 return PathDiagnosticLocation(S, SMgr, LC); 461 break; 462 case Stmt::DoStmtClass: 463 return PathDiagnosticLocation(S, SMgr, LC); 464 case Stmt::ForStmtClass: 465 if (cast<ForStmt>(Parent)->getBody() == S) 466 return PathDiagnosticLocation(S, SMgr, LC); 467 break; 468 case Stmt::IfStmtClass: 469 if (cast<IfStmt>(Parent)->getCond() != S) 470 return PathDiagnosticLocation(S, SMgr, LC); 471 break; 472 case Stmt::ObjCForCollectionStmtClass: 473 if (cast<ObjCForCollectionStmt>(Parent)->getBody() == S) 474 return PathDiagnosticLocation(S, SMgr, LC); 475 break; 476 case Stmt::WhileStmtClass: 477 if (cast<WhileStmt>(Parent)->getCond() != S) 478 return PathDiagnosticLocation(S, SMgr, LC); 479 break; 480 default: 481 break; 482 } 483 484 S = Parent; 485 } 486 487 assert(S && "Cannot have null Stmt for PathDiagnosticLocation"); 488 489 return PathDiagnosticLocation(S, SMgr, LC); 490} 491 492PathDiagnosticLocation 493PathDiagnosticBuilder::getEnclosingStmtLocation(const Stmt *S) { 494 assert(S && "Null Stmt passed to getEnclosingStmtLocation"); 495 return ::getEnclosingStmtLocation(S, getSourceManager(), getParentMap(), LC, 496 /*allowNestedContexts=*/false); 497} 498 499//===----------------------------------------------------------------------===// 500// "Visitors only" path diagnostic generation algorithm. 501//===----------------------------------------------------------------------===// 502static bool GenerateVisitorsOnlyPathDiagnostic( 503 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N, 504 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) { 505 // All path generation skips the very first node (the error node). 506 // This is because there is special handling for the end-of-path note. 507 N = N->getFirstPred(); 508 if (!N) 509 return true; 510 511 BugReport *R = PDB.getBugReport(); 512 while (const ExplodedNode *Pred = N->getFirstPred()) { 513 for (auto &V : visitors) { 514 // Visit all the node pairs, but throw the path pieces away. 515 PathDiagnosticPiece *Piece = V->VisitNode(N, Pred, PDB, *R); 516 delete Piece; 517 } 518 519 N = Pred; 520 } 521 522 return R->isValid(); 523} 524 525//===----------------------------------------------------------------------===// 526// "Minimal" path diagnostic generation algorithm. 527//===----------------------------------------------------------------------===// 528typedef std::pair<PathDiagnosticCallPiece*, const ExplodedNode*> StackDiagPair; 529typedef SmallVector<StackDiagPair, 6> StackDiagVector; 530 531static void updateStackPiecesWithMessage(PathDiagnosticPiece *P, 532 StackDiagVector &CallStack) { 533 // If the piece contains a special message, add it to all the call 534 // pieces on the active stack. 535 if (PathDiagnosticEventPiece *ep = 536 dyn_cast<PathDiagnosticEventPiece>(P)) { 537 538 if (ep->hasCallStackHint()) 539 for (StackDiagVector::iterator I = CallStack.begin(), 540 E = CallStack.end(); I != E; ++I) { 541 PathDiagnosticCallPiece *CP = I->first; 542 const ExplodedNode *N = I->second; 543 std::string stackMsg = ep->getCallStackMessage(N); 544 545 // The last message on the path to final bug is the most important 546 // one. Since we traverse the path backwards, do not add the message 547 // if one has been previously added. 548 if (!CP->hasCallStackMessage()) 549 CP->setCallStackMessage(stackMsg); 550 } 551 } 552} 553 554static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM); 555 556static bool GenerateMinimalPathDiagnostic( 557 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N, 558 LocationContextMap &LCM, 559 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) { 560 561 SourceManager& SMgr = PDB.getSourceManager(); 562 const LocationContext *LC = PDB.LC; 563 const ExplodedNode *NextNode = N->pred_empty() 564 ? nullptr : *(N->pred_begin()); 565 566 StackDiagVector CallStack; 567 568 while (NextNode) { 569 N = NextNode; 570 PDB.LC = N->getLocationContext(); 571 NextNode = N->getFirstPred(); 572 573 ProgramPoint P = N->getLocation(); 574 575 do { 576 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 577 PathDiagnosticCallPiece *C = 578 PathDiagnosticCallPiece::construct(N, *CE, SMgr); 579 // Record the mapping from call piece to LocationContext. 580 LCM[&C->path] = CE->getCalleeContext(); 581 PD.getActivePath().push_front(C); 582 PD.pushActivePath(&C->path); 583 CallStack.push_back(StackDiagPair(C, N)); 584 break; 585 } 586 587 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 588 // Flush all locations, and pop the active path. 589 bool VisitedEntireCall = PD.isWithinCall(); 590 PD.popActivePath(); 591 592 // Either we just added a bunch of stuff to the top-level path, or 593 // we have a previous CallExitEnd. If the former, it means that the 594 // path terminated within a function call. We must then take the 595 // current contents of the active path and place it within 596 // a new PathDiagnosticCallPiece. 597 PathDiagnosticCallPiece *C; 598 if (VisitedEntireCall) { 599 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 600 } else { 601 const Decl *Caller = CE->getLocationContext()->getDecl(); 602 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 603 // Record the mapping from call piece to LocationContext. 604 LCM[&C->path] = CE->getCalleeContext(); 605 } 606 607 C->setCallee(*CE, SMgr); 608 if (!CallStack.empty()) { 609 assert(CallStack.back().first == C); 610 CallStack.pop_back(); 611 } 612 break; 613 } 614 615 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 616 const CFGBlock *Src = BE->getSrc(); 617 const CFGBlock *Dst = BE->getDst(); 618 const Stmt *T = Src->getTerminator(); 619 620 if (!T) 621 break; 622 623 PathDiagnosticLocation Start = 624 PathDiagnosticLocation::createBegin(T, SMgr, 625 N->getLocationContext()); 626 627 switch (T->getStmtClass()) { 628 default: 629 break; 630 631 case Stmt::GotoStmtClass: 632 case Stmt::IndirectGotoStmtClass: { 633 const Stmt *S = PathDiagnosticLocation::getNextStmt(N); 634 635 if (!S) 636 break; 637 638 std::string sbuf; 639 llvm::raw_string_ostream os(sbuf); 640 const PathDiagnosticLocation &End = PDB.getEnclosingStmtLocation(S); 641 642 os << "Control jumps to line " 643 << End.asLocation().getExpansionLineNumber(); 644 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 645 Start, End, os.str())); 646 break; 647 } 648 649 case Stmt::SwitchStmtClass: { 650 // Figure out what case arm we took. 651 std::string sbuf; 652 llvm::raw_string_ostream os(sbuf); 653 654 if (const Stmt *S = Dst->getLabel()) { 655 PathDiagnosticLocation End(S, SMgr, LC); 656 657 switch (S->getStmtClass()) { 658 default: 659 os << "No cases match in the switch statement. " 660 "Control jumps to line " 661 << End.asLocation().getExpansionLineNumber(); 662 break; 663 case Stmt::DefaultStmtClass: 664 os << "Control jumps to the 'default' case at line " 665 << End.asLocation().getExpansionLineNumber(); 666 break; 667 668 case Stmt::CaseStmtClass: { 669 os << "Control jumps to 'case "; 670 const CaseStmt *Case = cast<CaseStmt>(S); 671 const Expr *LHS = Case->getLHS()->IgnoreParenCasts(); 672 673 // Determine if it is an enum. 674 bool GetRawInt = true; 675 676 if (const DeclRefExpr *DR = dyn_cast<DeclRefExpr>(LHS)) { 677 // FIXME: Maybe this should be an assertion. Are there cases 678 // were it is not an EnumConstantDecl? 679 const EnumConstantDecl *D = 680 dyn_cast<EnumConstantDecl>(DR->getDecl()); 681 682 if (D) { 683 GetRawInt = false; 684 os << *D; 685 } 686 } 687 688 if (GetRawInt) 689 os << LHS->EvaluateKnownConstInt(PDB.getASTContext()); 690 691 os << ":' at line " 692 << End.asLocation().getExpansionLineNumber(); 693 break; 694 } 695 } 696 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 697 Start, End, os.str())); 698 } 699 else { 700 os << "'Default' branch taken. "; 701 const PathDiagnosticLocation &End = PDB.ExecutionContinues(os, N); 702 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 703 Start, End, os.str())); 704 } 705 706 break; 707 } 708 709 case Stmt::BreakStmtClass: 710 case Stmt::ContinueStmtClass: { 711 std::string sbuf; 712 llvm::raw_string_ostream os(sbuf); 713 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 714 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 715 Start, End, os.str())); 716 break; 717 } 718 719 // Determine control-flow for ternary '?'. 720 case Stmt::BinaryConditionalOperatorClass: 721 case Stmt::ConditionalOperatorClass: { 722 std::string sbuf; 723 llvm::raw_string_ostream os(sbuf); 724 os << "'?' condition is "; 725 726 if (*(Src->succ_begin()+1) == Dst) 727 os << "false"; 728 else 729 os << "true"; 730 731 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 732 733 if (const Stmt *S = End.asStmt()) 734 End = PDB.getEnclosingStmtLocation(S); 735 736 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 737 Start, End, os.str())); 738 break; 739 } 740 741 // Determine control-flow for short-circuited '&&' and '||'. 742 case Stmt::BinaryOperatorClass: { 743 if (!PDB.supportsLogicalOpControlFlow()) 744 break; 745 746 const BinaryOperator *B = cast<BinaryOperator>(T); 747 std::string sbuf; 748 llvm::raw_string_ostream os(sbuf); 749 os << "Left side of '"; 750 751 if (B->getOpcode() == BO_LAnd) { 752 os << "&&" << "' is "; 753 754 if (*(Src->succ_begin()+1) == Dst) { 755 os << "false"; 756 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 757 PathDiagnosticLocation Start = 758 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 759 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 760 Start, End, os.str())); 761 } 762 else { 763 os << "true"; 764 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 765 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 766 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 767 Start, End, os.str())); 768 } 769 } 770 else { 771 assert(B->getOpcode() == BO_LOr); 772 os << "||" << "' is "; 773 774 if (*(Src->succ_begin()+1) == Dst) { 775 os << "false"; 776 PathDiagnosticLocation Start(B->getLHS(), SMgr, LC); 777 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 778 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 779 Start, End, os.str())); 780 } 781 else { 782 os << "true"; 783 PathDiagnosticLocation End(B->getLHS(), SMgr, LC); 784 PathDiagnosticLocation Start = 785 PathDiagnosticLocation::createOperatorLoc(B, SMgr); 786 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 787 Start, End, os.str())); 788 } 789 } 790 791 break; 792 } 793 794 case Stmt::DoStmtClass: { 795 if (*(Src->succ_begin()) == Dst) { 796 std::string sbuf; 797 llvm::raw_string_ostream os(sbuf); 798 799 os << "Loop condition is true. "; 800 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 801 802 if (const Stmt *S = End.asStmt()) 803 End = PDB.getEnclosingStmtLocation(S); 804 805 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 806 Start, End, os.str())); 807 } 808 else { 809 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 810 811 if (const Stmt *S = End.asStmt()) 812 End = PDB.getEnclosingStmtLocation(S); 813 814 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 815 Start, End, "Loop condition is false. Exiting loop")); 816 } 817 818 break; 819 } 820 821 case Stmt::WhileStmtClass: 822 case Stmt::ForStmtClass: { 823 if (*(Src->succ_begin()+1) == Dst) { 824 std::string sbuf; 825 llvm::raw_string_ostream os(sbuf); 826 827 os << "Loop condition is false. "; 828 PathDiagnosticLocation End = PDB.ExecutionContinues(os, N); 829 if (const Stmt *S = End.asStmt()) 830 End = PDB.getEnclosingStmtLocation(S); 831 832 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 833 Start, End, os.str())); 834 } 835 else { 836 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 837 if (const Stmt *S = End.asStmt()) 838 End = PDB.getEnclosingStmtLocation(S); 839 840 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 841 Start, End, "Loop condition is true. Entering loop body")); 842 } 843 844 break; 845 } 846 847 case Stmt::IfStmtClass: { 848 PathDiagnosticLocation End = PDB.ExecutionContinues(N); 849 850 if (const Stmt *S = End.asStmt()) 851 End = PDB.getEnclosingStmtLocation(S); 852 853 if (*(Src->succ_begin()+1) == Dst) 854 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 855 Start, End, "Taking false branch")); 856 else 857 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece( 858 Start, End, "Taking true branch")); 859 860 break; 861 } 862 } 863 } 864 } while(0); 865 866 if (NextNode) { 867 // Add diagnostic pieces from custom visitors. 868 BugReport *R = PDB.getBugReport(); 869 for (auto &V : visitors) { 870 if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *R)) { 871 PD.getActivePath().push_front(p); 872 updateStackPiecesWithMessage(p, CallStack); 873 } 874 } 875 } 876 } 877 878 if (!PDB.getBugReport()->isValid()) 879 return false; 880 881 // After constructing the full PathDiagnostic, do a pass over it to compact 882 // PathDiagnosticPieces that occur within a macro. 883 CompactPathDiagnostic(PD.getMutablePieces(), PDB.getSourceManager()); 884 return true; 885} 886 887//===----------------------------------------------------------------------===// 888// "Extensive" PathDiagnostic generation. 889//===----------------------------------------------------------------------===// 890 891static bool IsControlFlowExpr(const Stmt *S) { 892 const Expr *E = dyn_cast<Expr>(S); 893 894 if (!E) 895 return false; 896 897 E = E->IgnoreParenCasts(); 898 899 if (isa<AbstractConditionalOperator>(E)) 900 return true; 901 902 if (const BinaryOperator *B = dyn_cast<BinaryOperator>(E)) 903 if (B->isLogicalOp()) 904 return true; 905 906 return false; 907} 908 909namespace { 910class ContextLocation : public PathDiagnosticLocation { 911 bool IsDead; 912public: 913 ContextLocation(const PathDiagnosticLocation &L, bool isdead = false) 914 : PathDiagnosticLocation(L), IsDead(isdead) {} 915 916 void markDead() { IsDead = true; } 917 bool isDead() const { return IsDead; } 918}; 919 920static PathDiagnosticLocation cleanUpLocation(PathDiagnosticLocation L, 921 const LocationContext *LC, 922 bool firstCharOnly = false) { 923 if (const Stmt *S = L.asStmt()) { 924 const Stmt *Original = S; 925 while (1) { 926 // Adjust the location for some expressions that are best referenced 927 // by one of their subexpressions. 928 switch (S->getStmtClass()) { 929 default: 930 break; 931 case Stmt::ParenExprClass: 932 case Stmt::GenericSelectionExprClass: 933 S = cast<Expr>(S)->IgnoreParens(); 934 firstCharOnly = true; 935 continue; 936 case Stmt::BinaryConditionalOperatorClass: 937 case Stmt::ConditionalOperatorClass: 938 S = cast<AbstractConditionalOperator>(S)->getCond(); 939 firstCharOnly = true; 940 continue; 941 case Stmt::ChooseExprClass: 942 S = cast<ChooseExpr>(S)->getCond(); 943 firstCharOnly = true; 944 continue; 945 case Stmt::BinaryOperatorClass: 946 S = cast<BinaryOperator>(S)->getLHS(); 947 firstCharOnly = true; 948 continue; 949 } 950 951 break; 952 } 953 954 if (S != Original) 955 L = PathDiagnosticLocation(S, L.getManager(), LC); 956 } 957 958 if (firstCharOnly) 959 L = PathDiagnosticLocation::createSingleLocation(L); 960 961 return L; 962} 963 964class EdgeBuilder { 965 std::vector<ContextLocation> CLocs; 966 typedef std::vector<ContextLocation>::iterator iterator; 967 PathDiagnostic &PD; 968 PathDiagnosticBuilder &PDB; 969 PathDiagnosticLocation PrevLoc; 970 971 bool IsConsumedExpr(const PathDiagnosticLocation &L); 972 973 bool containsLocation(const PathDiagnosticLocation &Container, 974 const PathDiagnosticLocation &Containee); 975 976 PathDiagnosticLocation getContextLocation(const PathDiagnosticLocation &L); 977 978 979 980 void popLocation() { 981 if (!CLocs.back().isDead() && CLocs.back().asLocation().isFileID()) { 982 // For contexts, we only one the first character as the range. 983 rawAddEdge(cleanUpLocation(CLocs.back(), PDB.LC, true)); 984 } 985 CLocs.pop_back(); 986 } 987 988public: 989 EdgeBuilder(PathDiagnostic &pd, PathDiagnosticBuilder &pdb) 990 : PD(pd), PDB(pdb) { 991 992 // If the PathDiagnostic already has pieces, add the enclosing statement 993 // of the first piece as a context as well. 994 if (!PD.path.empty()) { 995 PrevLoc = (*PD.path.begin())->getLocation(); 996 997 if (const Stmt *S = PrevLoc.asStmt()) 998 addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 999 } 1000 } 1001 1002 ~EdgeBuilder() { 1003 while (!CLocs.empty()) popLocation(); 1004 1005 // Finally, add an initial edge from the start location of the first 1006 // statement (if it doesn't already exist). 1007 PathDiagnosticLocation L = PathDiagnosticLocation::createDeclBegin( 1008 PDB.LC, 1009 PDB.getSourceManager()); 1010 if (L.isValid()) 1011 rawAddEdge(L); 1012 } 1013 1014 void flushLocations() { 1015 while (!CLocs.empty()) 1016 popLocation(); 1017 PrevLoc = PathDiagnosticLocation(); 1018 } 1019 1020 void addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd = false, 1021 bool IsPostJump = false); 1022 1023 void rawAddEdge(PathDiagnosticLocation NewLoc); 1024 1025 void addContext(const Stmt *S); 1026 void addContext(const PathDiagnosticLocation &L); 1027 void addExtendedContext(const Stmt *S); 1028}; 1029} // end anonymous namespace 1030 1031 1032PathDiagnosticLocation 1033EdgeBuilder::getContextLocation(const PathDiagnosticLocation &L) { 1034 if (const Stmt *S = L.asStmt()) { 1035 if (IsControlFlowExpr(S)) 1036 return L; 1037 1038 return PDB.getEnclosingStmtLocation(S); 1039 } 1040 1041 return L; 1042} 1043 1044bool EdgeBuilder::containsLocation(const PathDiagnosticLocation &Container, 1045 const PathDiagnosticLocation &Containee) { 1046 1047 if (Container == Containee) 1048 return true; 1049 1050 if (Container.asDecl()) 1051 return true; 1052 1053 if (const Stmt *S = Containee.asStmt()) 1054 if (const Stmt *ContainerS = Container.asStmt()) { 1055 while (S) { 1056 if (S == ContainerS) 1057 return true; 1058 S = PDB.getParent(S); 1059 } 1060 return false; 1061 } 1062 1063 // Less accurate: compare using source ranges. 1064 SourceRange ContainerR = Container.asRange(); 1065 SourceRange ContaineeR = Containee.asRange(); 1066 1067 SourceManager &SM = PDB.getSourceManager(); 1068 SourceLocation ContainerRBeg = SM.getExpansionLoc(ContainerR.getBegin()); 1069 SourceLocation ContainerREnd = SM.getExpansionLoc(ContainerR.getEnd()); 1070 SourceLocation ContaineeRBeg = SM.getExpansionLoc(ContaineeR.getBegin()); 1071 SourceLocation ContaineeREnd = SM.getExpansionLoc(ContaineeR.getEnd()); 1072 1073 unsigned ContainerBegLine = SM.getExpansionLineNumber(ContainerRBeg); 1074 unsigned ContainerEndLine = SM.getExpansionLineNumber(ContainerREnd); 1075 unsigned ContaineeBegLine = SM.getExpansionLineNumber(ContaineeRBeg); 1076 unsigned ContaineeEndLine = SM.getExpansionLineNumber(ContaineeREnd); 1077 1078 assert(ContainerBegLine <= ContainerEndLine); 1079 assert(ContaineeBegLine <= ContaineeEndLine); 1080 1081 return (ContainerBegLine <= ContaineeBegLine && 1082 ContainerEndLine >= ContaineeEndLine && 1083 (ContainerBegLine != ContaineeBegLine || 1084 SM.getExpansionColumnNumber(ContainerRBeg) <= 1085 SM.getExpansionColumnNumber(ContaineeRBeg)) && 1086 (ContainerEndLine != ContaineeEndLine || 1087 SM.getExpansionColumnNumber(ContainerREnd) >= 1088 SM.getExpansionColumnNumber(ContaineeREnd))); 1089} 1090 1091void EdgeBuilder::rawAddEdge(PathDiagnosticLocation NewLoc) { 1092 if (!PrevLoc.isValid()) { 1093 PrevLoc = NewLoc; 1094 return; 1095 } 1096 1097 const PathDiagnosticLocation &NewLocClean = cleanUpLocation(NewLoc, PDB.LC); 1098 const PathDiagnosticLocation &PrevLocClean = cleanUpLocation(PrevLoc, PDB.LC); 1099 1100 if (PrevLocClean.asLocation().isInvalid()) { 1101 PrevLoc = NewLoc; 1102 return; 1103 } 1104 1105 if (NewLocClean.asLocation() == PrevLocClean.asLocation()) 1106 return; 1107 1108 // FIXME: Ignore intra-macro edges for now. 1109 if (NewLocClean.asLocation().getExpansionLoc() == 1110 PrevLocClean.asLocation().getExpansionLoc()) 1111 return; 1112 1113 PD.getActivePath().push_front(new PathDiagnosticControlFlowPiece(NewLocClean, PrevLocClean)); 1114 PrevLoc = NewLoc; 1115} 1116 1117void EdgeBuilder::addEdge(PathDiagnosticLocation NewLoc, bool alwaysAdd, 1118 bool IsPostJump) { 1119 1120 if (!alwaysAdd && NewLoc.asLocation().isMacroID()) 1121 return; 1122 1123 const PathDiagnosticLocation &CLoc = getContextLocation(NewLoc); 1124 1125 while (!CLocs.empty()) { 1126 ContextLocation &TopContextLoc = CLocs.back(); 1127 1128 // Is the top location context the same as the one for the new location? 1129 if (TopContextLoc == CLoc) { 1130 if (alwaysAdd) { 1131 if (IsConsumedExpr(TopContextLoc)) 1132 TopContextLoc.markDead(); 1133 1134 rawAddEdge(NewLoc); 1135 } 1136 1137 if (IsPostJump) 1138 TopContextLoc.markDead(); 1139 return; 1140 } 1141 1142 if (containsLocation(TopContextLoc, CLoc)) { 1143 if (alwaysAdd) { 1144 rawAddEdge(NewLoc); 1145 1146 if (IsConsumedExpr(CLoc)) { 1147 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/true)); 1148 return; 1149 } 1150 } 1151 1152 CLocs.push_back(ContextLocation(CLoc, /*IsDead=*/IsPostJump)); 1153 return; 1154 } 1155 1156 // Context does not contain the location. Flush it. 1157 popLocation(); 1158 } 1159 1160 // If we reach here, there is no enclosing context. Just add the edge. 1161 rawAddEdge(NewLoc); 1162} 1163 1164bool EdgeBuilder::IsConsumedExpr(const PathDiagnosticLocation &L) { 1165 if (const Expr *X = dyn_cast_or_null<Expr>(L.asStmt())) 1166 return PDB.getParentMap().isConsumedExpr(X) && !IsControlFlowExpr(X); 1167 1168 return false; 1169} 1170 1171void EdgeBuilder::addExtendedContext(const Stmt *S) { 1172 if (!S) 1173 return; 1174 1175 const Stmt *Parent = PDB.getParent(S); 1176 while (Parent) { 1177 if (isa<CompoundStmt>(Parent)) 1178 Parent = PDB.getParent(Parent); 1179 else 1180 break; 1181 } 1182 1183 if (Parent) { 1184 switch (Parent->getStmtClass()) { 1185 case Stmt::DoStmtClass: 1186 case Stmt::ObjCAtSynchronizedStmtClass: 1187 addContext(Parent); 1188 default: 1189 break; 1190 } 1191 } 1192 1193 addContext(S); 1194} 1195 1196void EdgeBuilder::addContext(const Stmt *S) { 1197 if (!S) 1198 return; 1199 1200 PathDiagnosticLocation L(S, PDB.getSourceManager(), PDB.LC); 1201 addContext(L); 1202} 1203 1204void EdgeBuilder::addContext(const PathDiagnosticLocation &L) { 1205 while (!CLocs.empty()) { 1206 const PathDiagnosticLocation &TopContextLoc = CLocs.back(); 1207 1208 // Is the top location context the same as the one for the new location? 1209 if (TopContextLoc == L) 1210 return; 1211 1212 if (containsLocation(TopContextLoc, L)) { 1213 CLocs.push_back(L); 1214 return; 1215 } 1216 1217 // Context does not contain the location. Flush it. 1218 popLocation(); 1219 } 1220 1221 CLocs.push_back(L); 1222} 1223 1224// Cone-of-influence: support the reverse propagation of "interesting" symbols 1225// and values by tracing interesting calculations backwards through evaluated 1226// expressions along a path. This is probably overly complicated, but the idea 1227// is that if an expression computed an "interesting" value, the child 1228// expressions are are also likely to be "interesting" as well (which then 1229// propagates to the values they in turn compute). This reverse propagation 1230// is needed to track interesting correlations across function call boundaries, 1231// where formal arguments bind to actual arguments, etc. This is also needed 1232// because the constraint solver sometimes simplifies certain symbolic values 1233// into constants when appropriate, and this complicates reasoning about 1234// interesting values. 1235typedef llvm::DenseSet<const Expr *> InterestingExprs; 1236 1237static void reversePropagateIntererstingSymbols(BugReport &R, 1238 InterestingExprs &IE, 1239 const ProgramState *State, 1240 const Expr *Ex, 1241 const LocationContext *LCtx) { 1242 SVal V = State->getSVal(Ex, LCtx); 1243 if (!(R.isInteresting(V) || IE.count(Ex))) 1244 return; 1245 1246 switch (Ex->getStmtClass()) { 1247 default: 1248 if (!isa<CastExpr>(Ex)) 1249 break; 1250 // Fall through. 1251 case Stmt::BinaryOperatorClass: 1252 case Stmt::UnaryOperatorClass: { 1253 for (const Stmt *SubStmt : Ex->children()) { 1254 if (const Expr *child = dyn_cast_or_null<Expr>(SubStmt)) { 1255 IE.insert(child); 1256 SVal ChildV = State->getSVal(child, LCtx); 1257 R.markInteresting(ChildV); 1258 } 1259 } 1260 break; 1261 } 1262 } 1263 1264 R.markInteresting(V); 1265} 1266 1267static void reversePropagateInterestingSymbols(BugReport &R, 1268 InterestingExprs &IE, 1269 const ProgramState *State, 1270 const LocationContext *CalleeCtx, 1271 const LocationContext *CallerCtx) 1272{ 1273 // FIXME: Handle non-CallExpr-based CallEvents. 1274 const StackFrameContext *Callee = CalleeCtx->getCurrentStackFrame(); 1275 const Stmt *CallSite = Callee->getCallSite(); 1276 if (const CallExpr *CE = dyn_cast_or_null<CallExpr>(CallSite)) { 1277 if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(CalleeCtx->getDecl())) { 1278 FunctionDecl::param_const_iterator PI = FD->param_begin(), 1279 PE = FD->param_end(); 1280 CallExpr::const_arg_iterator AI = CE->arg_begin(), AE = CE->arg_end(); 1281 for (; AI != AE && PI != PE; ++AI, ++PI) { 1282 if (const Expr *ArgE = *AI) { 1283 if (const ParmVarDecl *PD = *PI) { 1284 Loc LV = State->getLValue(PD, CalleeCtx); 1285 if (R.isInteresting(LV) || R.isInteresting(State->getRawSVal(LV))) 1286 IE.insert(ArgE); 1287 } 1288 } 1289 } 1290 } 1291 } 1292} 1293 1294//===----------------------------------------------------------------------===// 1295// Functions for determining if a loop was executed 0 times. 1296//===----------------------------------------------------------------------===// 1297 1298static bool isLoop(const Stmt *Term) { 1299 switch (Term->getStmtClass()) { 1300 case Stmt::ForStmtClass: 1301 case Stmt::WhileStmtClass: 1302 case Stmt::ObjCForCollectionStmtClass: 1303 case Stmt::CXXForRangeStmtClass: 1304 return true; 1305 default: 1306 // Note that we intentionally do not include do..while here. 1307 return false; 1308 } 1309} 1310 1311static bool isJumpToFalseBranch(const BlockEdge *BE) { 1312 const CFGBlock *Src = BE->getSrc(); 1313 assert(Src->succ_size() == 2); 1314 return (*(Src->succ_begin()+1) == BE->getDst()); 1315} 1316 1317/// Return true if the terminator is a loop and the destination is the 1318/// false branch. 1319static bool isLoopJumpPastBody(const Stmt *Term, const BlockEdge *BE) { 1320 if (!isLoop(Term)) 1321 return false; 1322 1323 // Did we take the false branch? 1324 return isJumpToFalseBranch(BE); 1325} 1326 1327static bool isContainedByStmt(ParentMap &PM, const Stmt *S, const Stmt *SubS) { 1328 while (SubS) { 1329 if (SubS == S) 1330 return true; 1331 SubS = PM.getParent(SubS); 1332 } 1333 return false; 1334} 1335 1336static const Stmt *getStmtBeforeCond(ParentMap &PM, const Stmt *Term, 1337 const ExplodedNode *N) { 1338 while (N) { 1339 Optional<StmtPoint> SP = N->getLocation().getAs<StmtPoint>(); 1340 if (SP) { 1341 const Stmt *S = SP->getStmt(); 1342 if (!isContainedByStmt(PM, Term, S)) 1343 return S; 1344 } 1345 N = N->getFirstPred(); 1346 } 1347 return nullptr; 1348} 1349 1350static bool isInLoopBody(ParentMap &PM, const Stmt *S, const Stmt *Term) { 1351 const Stmt *LoopBody = nullptr; 1352 switch (Term->getStmtClass()) { 1353 case Stmt::CXXForRangeStmtClass: { 1354 const CXXForRangeStmt *FR = cast<CXXForRangeStmt>(Term); 1355 if (isContainedByStmt(PM, FR->getInc(), S)) 1356 return true; 1357 if (isContainedByStmt(PM, FR->getLoopVarStmt(), S)) 1358 return true; 1359 LoopBody = FR->getBody(); 1360 break; 1361 } 1362 case Stmt::ForStmtClass: { 1363 const ForStmt *FS = cast<ForStmt>(Term); 1364 if (isContainedByStmt(PM, FS->getInc(), S)) 1365 return true; 1366 LoopBody = FS->getBody(); 1367 break; 1368 } 1369 case Stmt::ObjCForCollectionStmtClass: { 1370 const ObjCForCollectionStmt *FC = cast<ObjCForCollectionStmt>(Term); 1371 LoopBody = FC->getBody(); 1372 break; 1373 } 1374 case Stmt::WhileStmtClass: 1375 LoopBody = cast<WhileStmt>(Term)->getBody(); 1376 break; 1377 default: 1378 return false; 1379 } 1380 return isContainedByStmt(PM, LoopBody, S); 1381} 1382 1383//===----------------------------------------------------------------------===// 1384// Top-level logic for generating extensive path diagnostics. 1385//===----------------------------------------------------------------------===// 1386 1387static bool GenerateExtensivePathDiagnostic( 1388 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N, 1389 LocationContextMap &LCM, 1390 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) { 1391 EdgeBuilder EB(PD, PDB); 1392 const SourceManager& SM = PDB.getSourceManager(); 1393 StackDiagVector CallStack; 1394 InterestingExprs IE; 1395 1396 const ExplodedNode *NextNode = N->pred_empty() ? nullptr : *(N->pred_begin()); 1397 while (NextNode) { 1398 N = NextNode; 1399 NextNode = N->getFirstPred(); 1400 ProgramPoint P = N->getLocation(); 1401 1402 do { 1403 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1404 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1405 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1406 N->getState().get(), Ex, 1407 N->getLocationContext()); 1408 } 1409 1410 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1411 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1412 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1413 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1414 N->getState().get(), Ex, 1415 N->getLocationContext()); 1416 } 1417 1418 PathDiagnosticCallPiece *C = 1419 PathDiagnosticCallPiece::construct(N, *CE, SM); 1420 LCM[&C->path] = CE->getCalleeContext(); 1421 1422 EB.addEdge(C->callReturn, /*AlwaysAdd=*/true, /*IsPostJump=*/true); 1423 EB.flushLocations(); 1424 1425 PD.getActivePath().push_front(C); 1426 PD.pushActivePath(&C->path); 1427 CallStack.push_back(StackDiagPair(C, N)); 1428 break; 1429 } 1430 1431 // Pop the call hierarchy if we are done walking the contents 1432 // of a function call. 1433 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1434 // Add an edge to the start of the function. 1435 const Decl *D = CE->getCalleeContext()->getDecl(); 1436 PathDiagnosticLocation pos = 1437 PathDiagnosticLocation::createBegin(D, SM); 1438 EB.addEdge(pos); 1439 1440 // Flush all locations, and pop the active path. 1441 bool VisitedEntireCall = PD.isWithinCall(); 1442 EB.flushLocations(); 1443 PD.popActivePath(); 1444 PDB.LC = N->getLocationContext(); 1445 1446 // Either we just added a bunch of stuff to the top-level path, or 1447 // we have a previous CallExitEnd. If the former, it means that the 1448 // path terminated within a function call. We must then take the 1449 // current contents of the active path and place it within 1450 // a new PathDiagnosticCallPiece. 1451 PathDiagnosticCallPiece *C; 1452 if (VisitedEntireCall) { 1453 C = cast<PathDiagnosticCallPiece>(PD.getActivePath().front()); 1454 } else { 1455 const Decl *Caller = CE->getLocationContext()->getDecl(); 1456 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1457 LCM[&C->path] = CE->getCalleeContext(); 1458 } 1459 1460 C->setCallee(*CE, SM); 1461 EB.addContext(C->getLocation()); 1462 1463 if (!CallStack.empty()) { 1464 assert(CallStack.back().first == C); 1465 CallStack.pop_back(); 1466 } 1467 break; 1468 } 1469 1470 // Note that is important that we update the LocationContext 1471 // after looking at CallExits. CallExit basically adds an 1472 // edge in the *caller*, so we don't want to update the LocationContext 1473 // too soon. 1474 PDB.LC = N->getLocationContext(); 1475 1476 // Block edges. 1477 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1478 // Does this represent entering a call? If so, look at propagating 1479 // interesting symbols across call boundaries. 1480 if (NextNode) { 1481 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1482 const LocationContext *CalleeCtx = PDB.LC; 1483 if (CallerCtx != CalleeCtx) { 1484 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1485 N->getState().get(), 1486 CalleeCtx, CallerCtx); 1487 } 1488 } 1489 1490 // Are we jumping to the head of a loop? Add a special diagnostic. 1491 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1492 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1493 const CompoundStmt *CS = nullptr; 1494 1495 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1496 CS = dyn_cast<CompoundStmt>(FS->getBody()); 1497 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1498 CS = dyn_cast<CompoundStmt>(WS->getBody()); 1499 1500 PathDiagnosticEventPiece *p = 1501 new PathDiagnosticEventPiece(L, 1502 "Looping back to the head of the loop"); 1503 p->setPrunable(true); 1504 1505 EB.addEdge(p->getLocation(), true); 1506 PD.getActivePath().push_front(p); 1507 1508 if (CS) { 1509 PathDiagnosticLocation BL = 1510 PathDiagnosticLocation::createEndBrace(CS, SM); 1511 EB.addEdge(BL); 1512 } 1513 } 1514 1515 const CFGBlock *BSrc = BE->getSrc(); 1516 ParentMap &PM = PDB.getParentMap(); 1517 1518 if (const Stmt *Term = BSrc->getTerminator()) { 1519 // Are we jumping past the loop body without ever executing the 1520 // loop (because the condition was false)? 1521 if (isLoopJumpPastBody(Term, &*BE) && 1522 !isInLoopBody(PM, 1523 getStmtBeforeCond(PM, 1524 BSrc->getTerminatorCondition(), 1525 N), 1526 Term)) { 1527 PathDiagnosticLocation L(Term, SM, PDB.LC); 1528 PathDiagnosticEventPiece *PE = 1529 new PathDiagnosticEventPiece(L, "Loop body executed 0 times"); 1530 PE->setPrunable(true); 1531 1532 EB.addEdge(PE->getLocation(), true); 1533 PD.getActivePath().push_front(PE); 1534 } 1535 1536 // In any case, add the terminator as the current statement 1537 // context for control edges. 1538 EB.addContext(Term); 1539 } 1540 1541 break; 1542 } 1543 1544 if (Optional<BlockEntrance> BE = P.getAs<BlockEntrance>()) { 1545 Optional<CFGElement> First = BE->getFirstElement(); 1546 if (Optional<CFGStmt> S = First ? First->getAs<CFGStmt>() : None) { 1547 const Stmt *stmt = S->getStmt(); 1548 if (IsControlFlowExpr(stmt)) { 1549 // Add the proper context for '&&', '||', and '?'. 1550 EB.addContext(stmt); 1551 } 1552 else 1553 EB.addExtendedContext(PDB.getEnclosingStmtLocation(stmt).asStmt()); 1554 } 1555 1556 break; 1557 } 1558 1559 1560 } while (0); 1561 1562 if (!NextNode) 1563 continue; 1564 1565 // Add pieces from custom visitors. 1566 BugReport *R = PDB.getBugReport(); 1567 for (auto &V : visitors) { 1568 if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *R)) { 1569 const PathDiagnosticLocation &Loc = p->getLocation(); 1570 EB.addEdge(Loc, true); 1571 PD.getActivePath().push_front(p); 1572 updateStackPiecesWithMessage(p, CallStack); 1573 1574 if (const Stmt *S = Loc.asStmt()) 1575 EB.addExtendedContext(PDB.getEnclosingStmtLocation(S).asStmt()); 1576 } 1577 } 1578 } 1579 1580 return PDB.getBugReport()->isValid(); 1581} 1582 1583/// \brief Adds a sanitized control-flow diagnostic edge to a path. 1584static void addEdgeToPath(PathPieces &path, 1585 PathDiagnosticLocation &PrevLoc, 1586 PathDiagnosticLocation NewLoc, 1587 const LocationContext *LC) { 1588 if (!NewLoc.isValid()) 1589 return; 1590 1591 SourceLocation NewLocL = NewLoc.asLocation(); 1592 if (NewLocL.isInvalid()) 1593 return; 1594 1595 if (!PrevLoc.isValid() || !PrevLoc.asLocation().isValid()) { 1596 PrevLoc = NewLoc; 1597 return; 1598 } 1599 1600 // Ignore self-edges, which occur when there are multiple nodes at the same 1601 // statement. 1602 if (NewLoc.asStmt() && NewLoc.asStmt() == PrevLoc.asStmt()) 1603 return; 1604 1605 path.push_front(new PathDiagnosticControlFlowPiece(NewLoc, 1606 PrevLoc)); 1607 PrevLoc = NewLoc; 1608} 1609 1610/// A customized wrapper for CFGBlock::getTerminatorCondition() 1611/// which returns the element for ObjCForCollectionStmts. 1612static const Stmt *getTerminatorCondition(const CFGBlock *B) { 1613 const Stmt *S = B->getTerminatorCondition(); 1614 if (const ObjCForCollectionStmt *FS = 1615 dyn_cast_or_null<ObjCForCollectionStmt>(S)) 1616 return FS->getElement(); 1617 return S; 1618} 1619 1620static const char StrEnteringLoop[] = "Entering loop body"; 1621static const char StrLoopBodyZero[] = "Loop body executed 0 times"; 1622static const char StrLoopRangeEmpty[] = 1623 "Loop body skipped when range is empty"; 1624static const char StrLoopCollectionEmpty[] = 1625 "Loop body skipped when collection is empty"; 1626 1627static bool GenerateAlternateExtensivePathDiagnostic( 1628 PathDiagnostic &PD, PathDiagnosticBuilder &PDB, const ExplodedNode *N, 1629 LocationContextMap &LCM, 1630 ArrayRef<std::unique_ptr<BugReporterVisitor>> visitors) { 1631 1632 BugReport *report = PDB.getBugReport(); 1633 const SourceManager& SM = PDB.getSourceManager(); 1634 StackDiagVector CallStack; 1635 InterestingExprs IE; 1636 1637 PathDiagnosticLocation PrevLoc = PD.getLocation(); 1638 1639 const ExplodedNode *NextNode = N->getFirstPred(); 1640 while (NextNode) { 1641 N = NextNode; 1642 NextNode = N->getFirstPred(); 1643 ProgramPoint P = N->getLocation(); 1644 1645 do { 1646 // Have we encountered an entrance to a call? It may be 1647 // the case that we have not encountered a matching 1648 // call exit before this point. This means that the path 1649 // terminated within the call itself. 1650 if (Optional<CallEnter> CE = P.getAs<CallEnter>()) { 1651 // Add an edge to the start of the function. 1652 const StackFrameContext *CalleeLC = CE->getCalleeContext(); 1653 const Decl *D = CalleeLC->getDecl(); 1654 addEdgeToPath(PD.getActivePath(), PrevLoc, 1655 PathDiagnosticLocation::createBegin(D, SM), 1656 CalleeLC); 1657 1658 // Did we visit an entire call? 1659 bool VisitedEntireCall = PD.isWithinCall(); 1660 PD.popActivePath(); 1661 1662 PathDiagnosticCallPiece *C; 1663 if (VisitedEntireCall) { 1664 PathDiagnosticPiece *P = PD.getActivePath().front().get(); 1665 C = cast<PathDiagnosticCallPiece>(P); 1666 } else { 1667 const Decl *Caller = CE->getLocationContext()->getDecl(); 1668 C = PathDiagnosticCallPiece::construct(PD.getActivePath(), Caller); 1669 1670 // Since we just transferred the path over to the call piece, 1671 // reset the mapping from active to location context. 1672 assert(PD.getActivePath().size() == 1 && 1673 PD.getActivePath().front() == C); 1674 LCM[&PD.getActivePath()] = nullptr; 1675 1676 // Record the location context mapping for the path within 1677 // the call. 1678 assert(LCM[&C->path] == nullptr || 1679 LCM[&C->path] == CE->getCalleeContext()); 1680 LCM[&C->path] = CE->getCalleeContext(); 1681 1682 // If this is the first item in the active path, record 1683 // the new mapping from active path to location context. 1684 const LocationContext *&NewLC = LCM[&PD.getActivePath()]; 1685 if (!NewLC) 1686 NewLC = N->getLocationContext(); 1687 1688 PDB.LC = NewLC; 1689 } 1690 C->setCallee(*CE, SM); 1691 1692 // Update the previous location in the active path. 1693 PrevLoc = C->getLocation(); 1694 1695 if (!CallStack.empty()) { 1696 assert(CallStack.back().first == C); 1697 CallStack.pop_back(); 1698 } 1699 break; 1700 } 1701 1702 // Query the location context here and the previous location 1703 // as processing CallEnter may change the active path. 1704 PDB.LC = N->getLocationContext(); 1705 1706 // Record the mapping from the active path to the location 1707 // context. 1708 assert(!LCM[&PD.getActivePath()] || 1709 LCM[&PD.getActivePath()] == PDB.LC); 1710 LCM[&PD.getActivePath()] = PDB.LC; 1711 1712 // Have we encountered an exit from a function call? 1713 if (Optional<CallExitEnd> CE = P.getAs<CallExitEnd>()) { 1714 const Stmt *S = CE->getCalleeContext()->getCallSite(); 1715 // Propagate the interesting symbols accordingly. 1716 if (const Expr *Ex = dyn_cast_or_null<Expr>(S)) { 1717 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1718 N->getState().get(), Ex, 1719 N->getLocationContext()); 1720 } 1721 1722 // We are descending into a call (backwards). Construct 1723 // a new call piece to contain the path pieces for that call. 1724 PathDiagnosticCallPiece *C = 1725 PathDiagnosticCallPiece::construct(N, *CE, SM); 1726 1727 // Record the location context for this call piece. 1728 LCM[&C->path] = CE->getCalleeContext(); 1729 1730 // Add the edge to the return site. 1731 addEdgeToPath(PD.getActivePath(), PrevLoc, C->callReturn, PDB.LC); 1732 PD.getActivePath().push_front(C); 1733 PrevLoc.invalidate(); 1734 1735 // Make the contents of the call the active path for now. 1736 PD.pushActivePath(&C->path); 1737 CallStack.push_back(StackDiagPair(C, N)); 1738 break; 1739 } 1740 1741 if (Optional<PostStmt> PS = P.getAs<PostStmt>()) { 1742 // For expressions, make sure we propagate the 1743 // interesting symbols correctly. 1744 if (const Expr *Ex = PS->getStmtAs<Expr>()) 1745 reversePropagateIntererstingSymbols(*PDB.getBugReport(), IE, 1746 N->getState().get(), Ex, 1747 N->getLocationContext()); 1748 1749 // Add an edge. If this is an ObjCForCollectionStmt do 1750 // not add an edge here as it appears in the CFG both 1751 // as a terminator and as a terminator condition. 1752 if (!isa<ObjCForCollectionStmt>(PS->getStmt())) { 1753 PathDiagnosticLocation L = 1754 PathDiagnosticLocation(PS->getStmt(), SM, PDB.LC); 1755 addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC); 1756 } 1757 break; 1758 } 1759 1760 // Block edges. 1761 if (Optional<BlockEdge> BE = P.getAs<BlockEdge>()) { 1762 // Does this represent entering a call? If so, look at propagating 1763 // interesting symbols across call boundaries. 1764 if (NextNode) { 1765 const LocationContext *CallerCtx = NextNode->getLocationContext(); 1766 const LocationContext *CalleeCtx = PDB.LC; 1767 if (CallerCtx != CalleeCtx) { 1768 reversePropagateInterestingSymbols(*PDB.getBugReport(), IE, 1769 N->getState().get(), 1770 CalleeCtx, CallerCtx); 1771 } 1772 } 1773 1774 // Are we jumping to the head of a loop? Add a special diagnostic. 1775 if (const Stmt *Loop = BE->getSrc()->getLoopTarget()) { 1776 PathDiagnosticLocation L(Loop, SM, PDB.LC); 1777 const Stmt *Body = nullptr; 1778 1779 if (const ForStmt *FS = dyn_cast<ForStmt>(Loop)) 1780 Body = FS->getBody(); 1781 else if (const WhileStmt *WS = dyn_cast<WhileStmt>(Loop)) 1782 Body = WS->getBody(); 1783 else if (const ObjCForCollectionStmt *OFS = 1784 dyn_cast<ObjCForCollectionStmt>(Loop)) { 1785 Body = OFS->getBody(); 1786 } else if (const CXXForRangeStmt *FRS = 1787 dyn_cast<CXXForRangeStmt>(Loop)) { 1788 Body = FRS->getBody(); 1789 } 1790 // do-while statements are explicitly excluded here 1791 1792 PathDiagnosticEventPiece *p = 1793 new PathDiagnosticEventPiece(L, "Looping back to the head " 1794 "of the loop"); 1795 p->setPrunable(true); 1796 1797 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC); 1798 PD.getActivePath().push_front(p); 1799 1800 if (const CompoundStmt *CS = dyn_cast_or_null<CompoundStmt>(Body)) { 1801 addEdgeToPath(PD.getActivePath(), PrevLoc, 1802 PathDiagnosticLocation::createEndBrace(CS, SM), 1803 PDB.LC); 1804 } 1805 } 1806 1807 const CFGBlock *BSrc = BE->getSrc(); 1808 ParentMap &PM = PDB.getParentMap(); 1809 1810 if (const Stmt *Term = BSrc->getTerminator()) { 1811 // Are we jumping past the loop body without ever executing the 1812 // loop (because the condition was false)? 1813 if (isLoop(Term)) { 1814 const Stmt *TermCond = getTerminatorCondition(BSrc); 1815 bool IsInLoopBody = 1816 isInLoopBody(PM, getStmtBeforeCond(PM, TermCond, N), Term); 1817 1818 const char *str = nullptr; 1819 1820 if (isJumpToFalseBranch(&*BE)) { 1821 if (!IsInLoopBody) { 1822 if (isa<ObjCForCollectionStmt>(Term)) { 1823 str = StrLoopCollectionEmpty; 1824 } else if (isa<CXXForRangeStmt>(Term)) { 1825 str = StrLoopRangeEmpty; 1826 } else { 1827 str = StrLoopBodyZero; 1828 } 1829 } 1830 } else { 1831 str = StrEnteringLoop; 1832 } 1833 1834 if (str) { 1835 PathDiagnosticLocation L(TermCond ? TermCond : Term, SM, PDB.LC); 1836 PathDiagnosticEventPiece *PE = 1837 new PathDiagnosticEventPiece(L, str); 1838 PE->setPrunable(true); 1839 addEdgeToPath(PD.getActivePath(), PrevLoc, 1840 PE->getLocation(), PDB.LC); 1841 PD.getActivePath().push_front(PE); 1842 } 1843 } else if (isa<BreakStmt>(Term) || isa<ContinueStmt>(Term) || 1844 isa<GotoStmt>(Term)) { 1845 PathDiagnosticLocation L(Term, SM, PDB.LC); 1846 addEdgeToPath(PD.getActivePath(), PrevLoc, L, PDB.LC); 1847 } 1848 } 1849 break; 1850 } 1851 } while (0); 1852 1853 if (!NextNode) 1854 continue; 1855 1856 // Add pieces from custom visitors. 1857 for (auto &V : visitors) { 1858 if (PathDiagnosticPiece *p = V->VisitNode(N, NextNode, PDB, *report)) { 1859 addEdgeToPath(PD.getActivePath(), PrevLoc, p->getLocation(), PDB.LC); 1860 PD.getActivePath().push_front(p); 1861 updateStackPiecesWithMessage(p, CallStack); 1862 } 1863 } 1864 } 1865 1866 // Add an edge to the start of the function. 1867 // We'll prune it out later, but it helps make diagnostics more uniform. 1868 const StackFrameContext *CalleeLC = PDB.LC->getCurrentStackFrame(); 1869 const Decl *D = CalleeLC->getDecl(); 1870 addEdgeToPath(PD.getActivePath(), PrevLoc, 1871 PathDiagnosticLocation::createBegin(D, SM), 1872 CalleeLC); 1873 1874 return report->isValid(); 1875} 1876 1877static const Stmt *getLocStmt(PathDiagnosticLocation L) { 1878 if (!L.isValid()) 1879 return nullptr; 1880 return L.asStmt(); 1881} 1882 1883static const Stmt *getStmtParent(const Stmt *S, const ParentMap &PM) { 1884 if (!S) 1885 return nullptr; 1886 1887 while (true) { 1888 S = PM.getParentIgnoreParens(S); 1889 1890 if (!S) 1891 break; 1892 1893 if (isa<ExprWithCleanups>(S) || 1894 isa<CXXBindTemporaryExpr>(S) || 1895 isa<SubstNonTypeTemplateParmExpr>(S)) 1896 continue; 1897 1898 break; 1899 } 1900 1901 return S; 1902} 1903 1904static bool isConditionForTerminator(const Stmt *S, const Stmt *Cond) { 1905 switch (S->getStmtClass()) { 1906 case Stmt::BinaryOperatorClass: { 1907 const BinaryOperator *BO = cast<BinaryOperator>(S); 1908 if (!BO->isLogicalOp()) 1909 return false; 1910 return BO->getLHS() == Cond || BO->getRHS() == Cond; 1911 } 1912 case Stmt::IfStmtClass: 1913 return cast<IfStmt>(S)->getCond() == Cond; 1914 case Stmt::ForStmtClass: 1915 return cast<ForStmt>(S)->getCond() == Cond; 1916 case Stmt::WhileStmtClass: 1917 return cast<WhileStmt>(S)->getCond() == Cond; 1918 case Stmt::DoStmtClass: 1919 return cast<DoStmt>(S)->getCond() == Cond; 1920 case Stmt::ChooseExprClass: 1921 return cast<ChooseExpr>(S)->getCond() == Cond; 1922 case Stmt::IndirectGotoStmtClass: 1923 return cast<IndirectGotoStmt>(S)->getTarget() == Cond; 1924 case Stmt::SwitchStmtClass: 1925 return cast<SwitchStmt>(S)->getCond() == Cond; 1926 case Stmt::BinaryConditionalOperatorClass: 1927 return cast<BinaryConditionalOperator>(S)->getCond() == Cond; 1928 case Stmt::ConditionalOperatorClass: { 1929 const ConditionalOperator *CO = cast<ConditionalOperator>(S); 1930 return CO->getCond() == Cond || 1931 CO->getLHS() == Cond || 1932 CO->getRHS() == Cond; 1933 } 1934 case Stmt::ObjCForCollectionStmtClass: 1935 return cast<ObjCForCollectionStmt>(S)->getElement() == Cond; 1936 case Stmt::CXXForRangeStmtClass: { 1937 const CXXForRangeStmt *FRS = cast<CXXForRangeStmt>(S); 1938 return FRS->getCond() == Cond || FRS->getRangeInit() == Cond; 1939 } 1940 default: 1941 return false; 1942 } 1943} 1944 1945static bool isIncrementOrInitInForLoop(const Stmt *S, const Stmt *FL) { 1946 if (const ForStmt *FS = dyn_cast<ForStmt>(FL)) 1947 return FS->getInc() == S || FS->getInit() == S; 1948 if (const CXXForRangeStmt *FRS = dyn_cast<CXXForRangeStmt>(FL)) 1949 return FRS->getInc() == S || FRS->getRangeStmt() == S || 1950 FRS->getLoopVarStmt() || FRS->getRangeInit() == S; 1951 return false; 1952} 1953 1954typedef llvm::DenseSet<const PathDiagnosticCallPiece *> 1955 OptimizedCallsSet; 1956 1957/// Adds synthetic edges from top-level statements to their subexpressions. 1958/// 1959/// This avoids a "swoosh" effect, where an edge from a top-level statement A 1960/// points to a sub-expression B.1 that's not at the start of B. In these cases, 1961/// we'd like to see an edge from A to B, then another one from B to B.1. 1962static void addContextEdges(PathPieces &pieces, SourceManager &SM, 1963 const ParentMap &PM, const LocationContext *LCtx) { 1964 PathPieces::iterator Prev = pieces.end(); 1965 for (PathPieces::iterator I = pieces.begin(), E = Prev; I != E; 1966 Prev = I, ++I) { 1967 PathDiagnosticControlFlowPiece *Piece = 1968 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 1969 1970 if (!Piece) 1971 continue; 1972 1973 PathDiagnosticLocation SrcLoc = Piece->getStartLocation(); 1974 SmallVector<PathDiagnosticLocation, 4> SrcContexts; 1975 1976 PathDiagnosticLocation NextSrcContext = SrcLoc; 1977 const Stmt *InnerStmt = nullptr; 1978 while (NextSrcContext.isValid() && NextSrcContext.asStmt() != InnerStmt) { 1979 SrcContexts.push_back(NextSrcContext); 1980 InnerStmt = NextSrcContext.asStmt(); 1981 NextSrcContext = getEnclosingStmtLocation(InnerStmt, SM, PM, LCtx, 1982 /*allowNested=*/true); 1983 } 1984 1985 // Repeatedly split the edge as necessary. 1986 // This is important for nested logical expressions (||, &&, ?:) where we 1987 // want to show all the levels of context. 1988 while (true) { 1989 const Stmt *Dst = getLocStmt(Piece->getEndLocation()); 1990 1991 // We are looking at an edge. Is the destination within a larger 1992 // expression? 1993 PathDiagnosticLocation DstContext = 1994 getEnclosingStmtLocation(Dst, SM, PM, LCtx, /*allowNested=*/true); 1995 if (!DstContext.isValid() || DstContext.asStmt() == Dst) 1996 break; 1997 1998 // If the source is in the same context, we're already good. 1999 if (std::find(SrcContexts.begin(), SrcContexts.end(), DstContext) != 2000 SrcContexts.end()) 2001 break; 2002 2003 // Update the subexpression node to point to the context edge. 2004 Piece->setStartLocation(DstContext); 2005 2006 // Try to extend the previous edge if it's at the same level as the source 2007 // context. 2008 if (Prev != E) { 2009 PathDiagnosticControlFlowPiece *PrevPiece = 2010 dyn_cast<PathDiagnosticControlFlowPiece>(*Prev); 2011 2012 if (PrevPiece) { 2013 if (const Stmt *PrevSrc = getLocStmt(PrevPiece->getStartLocation())) { 2014 const Stmt *PrevSrcParent = getStmtParent(PrevSrc, PM); 2015 if (PrevSrcParent == getStmtParent(getLocStmt(DstContext), PM)) { 2016 PrevPiece->setEndLocation(DstContext); 2017 break; 2018 } 2019 } 2020 } 2021 } 2022 2023 // Otherwise, split the current edge into a context edge and a 2024 // subexpression edge. Note that the context statement may itself have 2025 // context. 2026 Piece = new PathDiagnosticControlFlowPiece(SrcLoc, DstContext); 2027 I = pieces.insert(I, Piece); 2028 } 2029 } 2030} 2031 2032/// \brief Move edges from a branch condition to a branch target 2033/// when the condition is simple. 2034/// 2035/// This restructures some of the work of addContextEdges. That function 2036/// creates edges this may destroy, but they work together to create a more 2037/// aesthetically set of edges around branches. After the call to 2038/// addContextEdges, we may have (1) an edge to the branch, (2) an edge from 2039/// the branch to the branch condition, and (3) an edge from the branch 2040/// condition to the branch target. We keep (1), but may wish to remove (2) 2041/// and move the source of (3) to the branch if the branch condition is simple. 2042/// 2043static void simplifySimpleBranches(PathPieces &pieces) { 2044 for (PathPieces::iterator I = pieces.begin(), E = pieces.end(); I != E; ++I) { 2045 2046 PathDiagnosticControlFlowPiece *PieceI = 2047 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2048 2049 if (!PieceI) 2050 continue; 2051 2052 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation()); 2053 const Stmt *s1End = getLocStmt(PieceI->getEndLocation()); 2054 2055 if (!s1Start || !s1End) 2056 continue; 2057 2058 PathPieces::iterator NextI = I; ++NextI; 2059 if (NextI == E) 2060 break; 2061 2062 PathDiagnosticControlFlowPiece *PieceNextI = nullptr; 2063 2064 while (true) { 2065 if (NextI == E) 2066 break; 2067 2068 PathDiagnosticEventPiece *EV = dyn_cast<PathDiagnosticEventPiece>(*NextI); 2069 if (EV) { 2070 StringRef S = EV->getString(); 2071 if (S == StrEnteringLoop || S == StrLoopBodyZero || 2072 S == StrLoopCollectionEmpty || S == StrLoopRangeEmpty) { 2073 ++NextI; 2074 continue; 2075 } 2076 break; 2077 } 2078 2079 PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 2080 break; 2081 } 2082 2083 if (!PieceNextI) 2084 continue; 2085 2086 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation()); 2087 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation()); 2088 2089 if (!s2Start || !s2End || s1End != s2Start) 2090 continue; 2091 2092 // We only perform this transformation for specific branch kinds. 2093 // We don't want to do this for do..while, for example. 2094 if (!(isa<ForStmt>(s1Start) || isa<WhileStmt>(s1Start) || 2095 isa<IfStmt>(s1Start) || isa<ObjCForCollectionStmt>(s1Start) || 2096 isa<CXXForRangeStmt>(s1Start))) 2097 continue; 2098 2099 // Is s1End the branch condition? 2100 if (!isConditionForTerminator(s1Start, s1End)) 2101 continue; 2102 2103 // Perform the hoisting by eliminating (2) and changing the start 2104 // location of (3). 2105 PieceNextI->setStartLocation(PieceI->getStartLocation()); 2106 I = pieces.erase(I); 2107 } 2108} 2109 2110/// Returns the number of bytes in the given (character-based) SourceRange. 2111/// 2112/// If the locations in the range are not on the same line, returns None. 2113/// 2114/// Note that this does not do a precise user-visible character or column count. 2115static Optional<size_t> getLengthOnSingleLine(SourceManager &SM, 2116 SourceRange Range) { 2117 SourceRange ExpansionRange(SM.getExpansionLoc(Range.getBegin()), 2118 SM.getExpansionRange(Range.getEnd()).second); 2119 2120 FileID FID = SM.getFileID(ExpansionRange.getBegin()); 2121 if (FID != SM.getFileID(ExpansionRange.getEnd())) 2122 return None; 2123 2124 bool Invalid; 2125 const llvm::MemoryBuffer *Buffer = SM.getBuffer(FID, &Invalid); 2126 if (Invalid) 2127 return None; 2128 2129 unsigned BeginOffset = SM.getFileOffset(ExpansionRange.getBegin()); 2130 unsigned EndOffset = SM.getFileOffset(ExpansionRange.getEnd()); 2131 StringRef Snippet = Buffer->getBuffer().slice(BeginOffset, EndOffset); 2132 2133 // We're searching the raw bytes of the buffer here, which might include 2134 // escaped newlines and such. That's okay; we're trying to decide whether the 2135 // SourceRange is covering a large or small amount of space in the user's 2136 // editor. 2137 if (Snippet.find_first_of("\r\n") != StringRef::npos) 2138 return None; 2139 2140 // This isn't Unicode-aware, but it doesn't need to be. 2141 return Snippet.size(); 2142} 2143 2144/// \sa getLengthOnSingleLine(SourceManager, SourceRange) 2145static Optional<size_t> getLengthOnSingleLine(SourceManager &SM, 2146 const Stmt *S) { 2147 return getLengthOnSingleLine(SM, S->getSourceRange()); 2148} 2149 2150/// Eliminate two-edge cycles created by addContextEdges(). 2151/// 2152/// Once all the context edges are in place, there are plenty of cases where 2153/// there's a single edge from a top-level statement to a subexpression, 2154/// followed by a single path note, and then a reverse edge to get back out to 2155/// the top level. If the statement is simple enough, the subexpression edges 2156/// just add noise and make it harder to understand what's going on. 2157/// 2158/// This function only removes edges in pairs, because removing only one edge 2159/// might leave other edges dangling. 2160/// 2161/// This will not remove edges in more complicated situations: 2162/// - if there is more than one "hop" leading to or from a subexpression. 2163/// - if there is an inlined call between the edges instead of a single event. 2164/// - if the whole statement is large enough that having subexpression arrows 2165/// might be helpful. 2166static void removeContextCycles(PathPieces &Path, SourceManager &SM, 2167 ParentMap &PM) { 2168 for (PathPieces::iterator I = Path.begin(), E = Path.end(); I != E; ) { 2169 // Pattern match the current piece and its successor. 2170 PathDiagnosticControlFlowPiece *PieceI = 2171 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2172 2173 if (!PieceI) { 2174 ++I; 2175 continue; 2176 } 2177 2178 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation()); 2179 const Stmt *s1End = getLocStmt(PieceI->getEndLocation()); 2180 2181 PathPieces::iterator NextI = I; ++NextI; 2182 if (NextI == E) 2183 break; 2184 2185 PathDiagnosticControlFlowPiece *PieceNextI = 2186 dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 2187 2188 if (!PieceNextI) { 2189 if (isa<PathDiagnosticEventPiece>(*NextI)) { 2190 ++NextI; 2191 if (NextI == E) 2192 break; 2193 PieceNextI = dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 2194 } 2195 2196 if (!PieceNextI) { 2197 ++I; 2198 continue; 2199 } 2200 } 2201 2202 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation()); 2203 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation()); 2204 2205 if (s1Start && s2Start && s1Start == s2End && s2Start == s1End) { 2206 const size_t MAX_SHORT_LINE_LENGTH = 80; 2207 Optional<size_t> s1Length = getLengthOnSingleLine(SM, s1Start); 2208 if (s1Length && *s1Length <= MAX_SHORT_LINE_LENGTH) { 2209 Optional<size_t> s2Length = getLengthOnSingleLine(SM, s2Start); 2210 if (s2Length && *s2Length <= MAX_SHORT_LINE_LENGTH) { 2211 Path.erase(I); 2212 I = Path.erase(NextI); 2213 continue; 2214 } 2215 } 2216 } 2217 2218 ++I; 2219 } 2220} 2221 2222/// \brief Return true if X is contained by Y. 2223static bool lexicalContains(ParentMap &PM, 2224 const Stmt *X, 2225 const Stmt *Y) { 2226 while (X) { 2227 if (X == Y) 2228 return true; 2229 X = PM.getParent(X); 2230 } 2231 return false; 2232} 2233 2234// Remove short edges on the same line less than 3 columns in difference. 2235static void removePunyEdges(PathPieces &path, 2236 SourceManager &SM, 2237 ParentMap &PM) { 2238 2239 bool erased = false; 2240 2241 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; 2242 erased ? I : ++I) { 2243 2244 erased = false; 2245 2246 PathDiagnosticControlFlowPiece *PieceI = 2247 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2248 2249 if (!PieceI) 2250 continue; 2251 2252 const Stmt *start = getLocStmt(PieceI->getStartLocation()); 2253 const Stmt *end = getLocStmt(PieceI->getEndLocation()); 2254 2255 if (!start || !end) 2256 continue; 2257 2258 const Stmt *endParent = PM.getParent(end); 2259 if (!endParent) 2260 continue; 2261 2262 if (isConditionForTerminator(end, endParent)) 2263 continue; 2264 2265 SourceLocation FirstLoc = start->getLocStart(); 2266 SourceLocation SecondLoc = end->getLocStart(); 2267 2268 if (!SM.isWrittenInSameFile(FirstLoc, SecondLoc)) 2269 continue; 2270 if (SM.isBeforeInTranslationUnit(SecondLoc, FirstLoc)) 2271 std::swap(SecondLoc, FirstLoc); 2272 2273 SourceRange EdgeRange(FirstLoc, SecondLoc); 2274 Optional<size_t> ByteWidth = getLengthOnSingleLine(SM, EdgeRange); 2275 2276 // If the statements are on different lines, continue. 2277 if (!ByteWidth) 2278 continue; 2279 2280 const size_t MAX_PUNY_EDGE_LENGTH = 2; 2281 if (*ByteWidth <= MAX_PUNY_EDGE_LENGTH) { 2282 // FIXME: There are enough /bytes/ between the endpoints of the edge, but 2283 // there might not be enough /columns/. A proper user-visible column count 2284 // is probably too expensive, though. 2285 I = path.erase(I); 2286 erased = true; 2287 continue; 2288 } 2289 } 2290} 2291 2292static void removeIdenticalEvents(PathPieces &path) { 2293 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ++I) { 2294 PathDiagnosticEventPiece *PieceI = 2295 dyn_cast<PathDiagnosticEventPiece>(*I); 2296 2297 if (!PieceI) 2298 continue; 2299 2300 PathPieces::iterator NextI = I; ++NextI; 2301 if (NextI == E) 2302 return; 2303 2304 PathDiagnosticEventPiece *PieceNextI = 2305 dyn_cast<PathDiagnosticEventPiece>(*NextI); 2306 2307 if (!PieceNextI) 2308 continue; 2309 2310 // Erase the second piece if it has the same exact message text. 2311 if (PieceI->getString() == PieceNextI->getString()) { 2312 path.erase(NextI); 2313 } 2314 } 2315} 2316 2317static bool optimizeEdges(PathPieces &path, SourceManager &SM, 2318 OptimizedCallsSet &OCS, 2319 LocationContextMap &LCM) { 2320 bool hasChanges = false; 2321 const LocationContext *LC = LCM[&path]; 2322 assert(LC); 2323 ParentMap &PM = LC->getParentMap(); 2324 2325 for (PathPieces::iterator I = path.begin(), E = path.end(); I != E; ) { 2326 // Optimize subpaths. 2327 if (PathDiagnosticCallPiece *CallI = dyn_cast<PathDiagnosticCallPiece>(*I)){ 2328 // Record the fact that a call has been optimized so we only do the 2329 // effort once. 2330 if (!OCS.count(CallI)) { 2331 while (optimizeEdges(CallI->path, SM, OCS, LCM)) {} 2332 OCS.insert(CallI); 2333 } 2334 ++I; 2335 continue; 2336 } 2337 2338 // Pattern match the current piece and its successor. 2339 PathDiagnosticControlFlowPiece *PieceI = 2340 dyn_cast<PathDiagnosticControlFlowPiece>(*I); 2341 2342 if (!PieceI) { 2343 ++I; 2344 continue; 2345 } 2346 2347 const Stmt *s1Start = getLocStmt(PieceI->getStartLocation()); 2348 const Stmt *s1End = getLocStmt(PieceI->getEndLocation()); 2349 const Stmt *level1 = getStmtParent(s1Start, PM); 2350 const Stmt *level2 = getStmtParent(s1End, PM); 2351 2352 PathPieces::iterator NextI = I; ++NextI; 2353 if (NextI == E) 2354 break; 2355 2356 PathDiagnosticControlFlowPiece *PieceNextI = 2357 dyn_cast<PathDiagnosticControlFlowPiece>(*NextI); 2358 2359 if (!PieceNextI) { 2360 ++I; 2361 continue; 2362 } 2363 2364 const Stmt *s2Start = getLocStmt(PieceNextI->getStartLocation()); 2365 const Stmt *s2End = getLocStmt(PieceNextI->getEndLocation()); 2366 const Stmt *level3 = getStmtParent(s2Start, PM); 2367 const Stmt *level4 = getStmtParent(s2End, PM); 2368 2369 // Rule I. 2370 // 2371 // If we have two consecutive control edges whose end/begin locations 2372 // are at the same level (e.g. statements or top-level expressions within 2373 // a compound statement, or siblings share a single ancestor expression), 2374 // then merge them if they have no interesting intermediate event. 2375 // 2376 // For example: 2377 // 2378 // (1.1 -> 1.2) -> (1.2 -> 1.3) becomes (1.1 -> 1.3) because the common 2379 // parent is '1'. Here 'x.y.z' represents the hierarchy of statements. 2380 // 2381 // NOTE: this will be limited later in cases where we add barriers 2382 // to prevent this optimization. 2383 // 2384 if (level1 && level1 == level2 && level1 == level3 && level1 == level4) { 2385 PieceI->setEndLocation(PieceNextI->getEndLocation()); 2386 path.erase(NextI); 2387 hasChanges = true; 2388 continue; 2389 } 2390 2391 // Rule II. 2392 // 2393 // Eliminate edges between subexpressions and parent expressions 2394 // when the subexpression is consumed. 2395 // 2396 // NOTE: this will be limited later in cases where we add barriers 2397 // to prevent this optimization. 2398 // 2399 if (s1End && s1End == s2Start && level2) { 2400 bool removeEdge = false; 2401 // Remove edges into the increment or initialization of a 2402 // loop that have no interleaving event. This means that 2403 // they aren't interesting. 2404 if (isIncrementOrInitInForLoop(s1End, level2)) 2405 removeEdge = true; 2406 // Next only consider edges that are not anchored on 2407 // the condition of a terminator. This are intermediate edges 2408 // that we might want to trim. 2409 else if (!isConditionForTerminator(level2, s1End)) { 2410 // Trim edges on expressions that are consumed by 2411 // the parent expression. 2412 if (isa<Expr>(s1End) && PM.isConsumedExpr(cast<Expr>(s1End))) { 2413 removeEdge = true; 2414 } 2415 // Trim edges where a lexical containment doesn't exist. 2416 // For example: 2417 // 2418 // X -> Y -> Z 2419 // 2420 // If 'Z' lexically contains Y (it is an ancestor) and 2421 // 'X' does not lexically contain Y (it is a descendant OR 2422 // it has no lexical relationship at all) then trim. 2423 // 2424 // This can eliminate edges where we dive into a subexpression 2425 // and then pop back out, etc. 2426 else if (s1Start && s2End && 2427 lexicalContains(PM, s2Start, s2End) && 2428 !lexicalContains(PM, s1End, s1Start)) { 2429 removeEdge = true; 2430 } 2431 // Trim edges from a subexpression back to the top level if the 2432 // subexpression is on a different line. 2433 // 2434 // A.1 -> A -> B 2435 // becomes 2436 // A.1 -> B 2437 // 2438 // These edges just look ugly and don't usually add anything. 2439 else if (s1Start && s2End && 2440 lexicalContains(PM, s1Start, s1End)) { 2441 SourceRange EdgeRange(PieceI->getEndLocation().asLocation(), 2442 PieceI->getStartLocation().asLocation()); 2443 if (!getLengthOnSingleLine(SM, EdgeRange).hasValue()) 2444 removeEdge = true; 2445 } 2446 } 2447 2448 if (removeEdge) { 2449 PieceI->setEndLocation(PieceNextI->getEndLocation()); 2450 path.erase(NextI); 2451 hasChanges = true; 2452 continue; 2453 } 2454 } 2455 2456 // Optimize edges for ObjC fast-enumeration loops. 2457 // 2458 // (X -> collection) -> (collection -> element) 2459 // 2460 // becomes: 2461 // 2462 // (X -> element) 2463 if (s1End == s2Start) { 2464 const ObjCForCollectionStmt *FS = 2465 dyn_cast_or_null<ObjCForCollectionStmt>(level3); 2466 if (FS && FS->getCollection()->IgnoreParens() == s2Start && 2467 s2End == FS->getElement()) { 2468 PieceI->setEndLocation(PieceNextI->getEndLocation()); 2469 path.erase(NextI); 2470 hasChanges = true; 2471 continue; 2472 } 2473 } 2474 2475 // No changes at this index? Move to the next one. 2476 ++I; 2477 } 2478 2479 if (!hasChanges) { 2480 // Adjust edges into subexpressions to make them more uniform 2481 // and aesthetically pleasing. 2482 addContextEdges(path, SM, PM, LC); 2483 // Remove "cyclical" edges that include one or more context edges. 2484 removeContextCycles(path, SM, PM); 2485 // Hoist edges originating from branch conditions to branches 2486 // for simple branches. 2487 simplifySimpleBranches(path); 2488 // Remove any puny edges left over after primary optimization pass. 2489 removePunyEdges(path, SM, PM); 2490 // Remove identical events. 2491 removeIdenticalEvents(path); 2492 } 2493 2494 return hasChanges; 2495} 2496 2497/// Drop the very first edge in a path, which should be a function entry edge. 2498/// 2499/// If the first edge is not a function entry edge (say, because the first 2500/// statement had an invalid source location), this function does nothing. 2501// FIXME: We should just generate invalid edges anyway and have the optimizer 2502// deal with them. 2503static void dropFunctionEntryEdge(PathPieces &Path, 2504 LocationContextMap &LCM, 2505 SourceManager &SM) { 2506 const PathDiagnosticControlFlowPiece *FirstEdge = 2507 dyn_cast<PathDiagnosticControlFlowPiece>(Path.front()); 2508 if (!FirstEdge) 2509 return; 2510 2511 const Decl *D = LCM[&Path]->getDecl(); 2512 PathDiagnosticLocation EntryLoc = PathDiagnosticLocation::createBegin(D, SM); 2513 if (FirstEdge->getStartLocation() != EntryLoc) 2514 return; 2515 2516 Path.pop_front(); 2517} 2518 2519 2520//===----------------------------------------------------------------------===// 2521// Methods for BugType and subclasses. 2522//===----------------------------------------------------------------------===// 2523void BugType::anchor() { } 2524 2525void BugType::FlushReports(BugReporter &BR) {} 2526 2527void BuiltinBug::anchor() {} 2528 2529//===----------------------------------------------------------------------===// 2530// Methods for BugReport and subclasses. 2531//===----------------------------------------------------------------------===// 2532 2533void BugReport::NodeResolver::anchor() {} 2534 2535void BugReport::addVisitor(std::unique_ptr<BugReporterVisitor> visitor) { 2536 if (!visitor) 2537 return; 2538 2539 llvm::FoldingSetNodeID ID; 2540 visitor->Profile(ID); 2541 void *InsertPos; 2542 2543 if (CallbacksSet.FindNodeOrInsertPos(ID, InsertPos)) 2544 return; 2545 2546 CallbacksSet.InsertNode(visitor.get(), InsertPos); 2547 Callbacks.push_back(std::move(visitor)); 2548 ++ConfigurationChangeToken; 2549} 2550 2551BugReport::~BugReport() { 2552 while (!interestingSymbols.empty()) { 2553 popInterestingSymbolsAndRegions(); 2554 } 2555} 2556 2557const Decl *BugReport::getDeclWithIssue() const { 2558 if (DeclWithIssue) 2559 return DeclWithIssue; 2560 2561 const ExplodedNode *N = getErrorNode(); 2562 if (!N) 2563 return nullptr; 2564 2565 const LocationContext *LC = N->getLocationContext(); 2566 return LC->getCurrentStackFrame()->getDecl(); 2567} 2568 2569void BugReport::Profile(llvm::FoldingSetNodeID& hash) const { 2570 hash.AddPointer(&BT); 2571 hash.AddString(Description); 2572 PathDiagnosticLocation UL = getUniqueingLocation(); 2573 if (UL.isValid()) { 2574 UL.Profile(hash); 2575 } else if (Location.isValid()) { 2576 Location.Profile(hash); 2577 } else { 2578 assert(ErrorNode); 2579 hash.AddPointer(GetCurrentOrPreviousStmt(ErrorNode)); 2580 } 2581 2582 for (SmallVectorImpl<SourceRange>::const_iterator I = 2583 Ranges.begin(), E = Ranges.end(); I != E; ++I) { 2584 const SourceRange range = *I; 2585 if (!range.isValid()) 2586 continue; 2587 hash.AddInteger(range.getBegin().getRawEncoding()); 2588 hash.AddInteger(range.getEnd().getRawEncoding()); 2589 } 2590} 2591 2592void BugReport::markInteresting(SymbolRef sym) { 2593 if (!sym) 2594 return; 2595 2596 // If the symbol wasn't already in our set, note a configuration change. 2597 if (getInterestingSymbols().insert(sym).second) 2598 ++ConfigurationChangeToken; 2599 2600 if (const SymbolMetadata *meta = dyn_cast<SymbolMetadata>(sym)) 2601 getInterestingRegions().insert(meta->getRegion()); 2602} 2603 2604void BugReport::markInteresting(const MemRegion *R) { 2605 if (!R) 2606 return; 2607 2608 // If the base region wasn't already in our set, note a configuration change. 2609 R = R->getBaseRegion(); 2610 if (getInterestingRegions().insert(R).second) 2611 ++ConfigurationChangeToken; 2612 2613 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2614 getInterestingSymbols().insert(SR->getSymbol()); 2615} 2616 2617void BugReport::markInteresting(SVal V) { 2618 markInteresting(V.getAsRegion()); 2619 markInteresting(V.getAsSymbol()); 2620} 2621 2622void BugReport::markInteresting(const LocationContext *LC) { 2623 if (!LC) 2624 return; 2625 InterestingLocationContexts.insert(LC); 2626} 2627 2628bool BugReport::isInteresting(SVal V) { 2629 return isInteresting(V.getAsRegion()) || isInteresting(V.getAsSymbol()); 2630} 2631 2632bool BugReport::isInteresting(SymbolRef sym) { 2633 if (!sym) 2634 return false; 2635 // We don't currently consider metadata symbols to be interesting 2636 // even if we know their region is interesting. Is that correct behavior? 2637 return getInterestingSymbols().count(sym); 2638} 2639 2640bool BugReport::isInteresting(const MemRegion *R) { 2641 if (!R) 2642 return false; 2643 R = R->getBaseRegion(); 2644 bool b = getInterestingRegions().count(R); 2645 if (b) 2646 return true; 2647 if (const SymbolicRegion *SR = dyn_cast<SymbolicRegion>(R)) 2648 return getInterestingSymbols().count(SR->getSymbol()); 2649 return false; 2650} 2651 2652bool BugReport::isInteresting(const LocationContext *LC) { 2653 if (!LC) 2654 return false; 2655 return InterestingLocationContexts.count(LC); 2656} 2657 2658void BugReport::lazyInitializeInterestingSets() { 2659 if (interestingSymbols.empty()) { 2660 interestingSymbols.push_back(new Symbols()); 2661 interestingRegions.push_back(new Regions()); 2662 } 2663} 2664 2665BugReport::Symbols &BugReport::getInterestingSymbols() { 2666 lazyInitializeInterestingSets(); 2667 return *interestingSymbols.back(); 2668} 2669 2670BugReport::Regions &BugReport::getInterestingRegions() { 2671 lazyInitializeInterestingSets(); 2672 return *interestingRegions.back(); 2673} 2674 2675void BugReport::pushInterestingSymbolsAndRegions() { 2676 interestingSymbols.push_back(new Symbols(getInterestingSymbols())); 2677 interestingRegions.push_back(new Regions(getInterestingRegions())); 2678} 2679 2680void BugReport::popInterestingSymbolsAndRegions() { 2681 delete interestingSymbols.pop_back_val(); 2682 delete interestingRegions.pop_back_val(); 2683} 2684 2685const Stmt *BugReport::getStmt() const { 2686 if (!ErrorNode) 2687 return nullptr; 2688 2689 ProgramPoint ProgP = ErrorNode->getLocation(); 2690 const Stmt *S = nullptr; 2691 2692 if (Optional<BlockEntrance> BE = ProgP.getAs<BlockEntrance>()) { 2693 CFGBlock &Exit = ProgP.getLocationContext()->getCFG()->getExit(); 2694 if (BE->getBlock() == &Exit) 2695 S = GetPreviousStmt(ErrorNode); 2696 } 2697 if (!S) 2698 S = PathDiagnosticLocation::getStmt(ErrorNode); 2699 2700 return S; 2701} 2702 2703llvm::iterator_range<BugReport::ranges_iterator> BugReport::getRanges() { 2704 // If no custom ranges, add the range of the statement corresponding to 2705 // the error node. 2706 if (Ranges.empty()) { 2707 if (const Expr *E = dyn_cast_or_null<Expr>(getStmt())) 2708 addRange(E->getSourceRange()); 2709 else 2710 return llvm::make_range(ranges_iterator(), ranges_iterator()); 2711 } 2712 2713 // User-specified absence of range info. 2714 if (Ranges.size() == 1 && !Ranges.begin()->isValid()) 2715 return llvm::make_range(ranges_iterator(), ranges_iterator()); 2716 2717 return llvm::iterator_range<BugReport::ranges_iterator>(Ranges.begin(), 2718 Ranges.end()); 2719} 2720 2721PathDiagnosticLocation BugReport::getLocation(const SourceManager &SM) const { 2722 if (ErrorNode) { 2723 assert(!Location.isValid() && 2724 "Either Location or ErrorNode should be specified but not both."); 2725 return PathDiagnosticLocation::createEndOfPath(ErrorNode, SM); 2726 } 2727 2728 assert(Location.isValid()); 2729 return Location; 2730} 2731 2732//===----------------------------------------------------------------------===// 2733// Methods for BugReporter and subclasses. 2734//===----------------------------------------------------------------------===// 2735 2736BugReportEquivClass::~BugReportEquivClass() { } 2737GRBugReporter::~GRBugReporter() { } 2738BugReporterData::~BugReporterData() {} 2739 2740ExplodedGraph &GRBugReporter::getGraph() { return Eng.getGraph(); } 2741 2742ProgramStateManager& 2743GRBugReporter::getStateManager() { return Eng.getStateManager(); } 2744 2745BugReporter::~BugReporter() { 2746 FlushReports(); 2747 2748 // Free the bug reports we are tracking. 2749 typedef std::vector<BugReportEquivClass *> ContTy; 2750 for (ContTy::iterator I = EQClassesVector.begin(), E = EQClassesVector.end(); 2751 I != E; ++I) { 2752 delete *I; 2753 } 2754} 2755 2756void BugReporter::FlushReports() { 2757 if (BugTypes.isEmpty()) 2758 return; 2759 2760 // First flush the warnings for each BugType. This may end up creating new 2761 // warnings and new BugTypes. 2762 // FIXME: Only NSErrorChecker needs BugType's FlushReports. 2763 // Turn NSErrorChecker into a proper checker and remove this. 2764 SmallVector<const BugType *, 16> bugTypes(BugTypes.begin(), BugTypes.end()); 2765 for (SmallVectorImpl<const BugType *>::iterator 2766 I = bugTypes.begin(), E = bugTypes.end(); I != E; ++I) 2767 const_cast<BugType*>(*I)->FlushReports(*this); 2768 2769 // We need to flush reports in deterministic order to ensure the order 2770 // of the reports is consistent between runs. 2771 typedef std::vector<BugReportEquivClass *> ContVecTy; 2772 for (ContVecTy::iterator EI=EQClassesVector.begin(), EE=EQClassesVector.end(); 2773 EI != EE; ++EI){ 2774 BugReportEquivClass& EQ = **EI; 2775 FlushReport(EQ); 2776 } 2777 2778 // BugReporter owns and deletes only BugTypes created implicitly through 2779 // EmitBasicReport. 2780 // FIXME: There are leaks from checkers that assume that the BugTypes they 2781 // create will be destroyed by the BugReporter. 2782 llvm::DeleteContainerSeconds(StrBugTypes); 2783 2784 // Remove all references to the BugType objects. 2785 BugTypes = F.getEmptySet(); 2786} 2787 2788//===----------------------------------------------------------------------===// 2789// PathDiagnostics generation. 2790//===----------------------------------------------------------------------===// 2791 2792namespace { 2793/// A wrapper around a report graph, which contains only a single path, and its 2794/// node maps. 2795class ReportGraph { 2796public: 2797 InterExplodedGraphMap BackMap; 2798 std::unique_ptr<ExplodedGraph> Graph; 2799 const ExplodedNode *ErrorNode; 2800 size_t Index; 2801}; 2802 2803/// A wrapper around a trimmed graph and its node maps. 2804class TrimmedGraph { 2805 InterExplodedGraphMap InverseMap; 2806 2807 typedef llvm::DenseMap<const ExplodedNode *, unsigned> PriorityMapTy; 2808 PriorityMapTy PriorityMap; 2809 2810 typedef std::pair<const ExplodedNode *, size_t> NodeIndexPair; 2811 SmallVector<NodeIndexPair, 32> ReportNodes; 2812 2813 std::unique_ptr<ExplodedGraph> G; 2814 2815 /// A helper class for sorting ExplodedNodes by priority. 2816 template <bool Descending> 2817 class PriorityCompare { 2818 const PriorityMapTy &PriorityMap; 2819 2820 public: 2821 PriorityCompare(const PriorityMapTy &M) : PriorityMap(M) {} 2822 2823 bool operator()(const ExplodedNode *LHS, const ExplodedNode *RHS) const { 2824 PriorityMapTy::const_iterator LI = PriorityMap.find(LHS); 2825 PriorityMapTy::const_iterator RI = PriorityMap.find(RHS); 2826 PriorityMapTy::const_iterator E = PriorityMap.end(); 2827 2828 if (LI == E) 2829 return Descending; 2830 if (RI == E) 2831 return !Descending; 2832 2833 return Descending ? LI->second > RI->second 2834 : LI->second < RI->second; 2835 } 2836 2837 bool operator()(const NodeIndexPair &LHS, const NodeIndexPair &RHS) const { 2838 return (*this)(LHS.first, RHS.first); 2839 } 2840 }; 2841 2842public: 2843 TrimmedGraph(const ExplodedGraph *OriginalGraph, 2844 ArrayRef<const ExplodedNode *> Nodes); 2845 2846 bool popNextReportGraph(ReportGraph &GraphWrapper); 2847}; 2848} 2849 2850TrimmedGraph::TrimmedGraph(const ExplodedGraph *OriginalGraph, 2851 ArrayRef<const ExplodedNode *> Nodes) { 2852 // The trimmed graph is created in the body of the constructor to ensure 2853 // that the DenseMaps have been initialized already. 2854 InterExplodedGraphMap ForwardMap; 2855 G = OriginalGraph->trim(Nodes, &ForwardMap, &InverseMap); 2856 2857 // Find the (first) error node in the trimmed graph. We just need to consult 2858 // the node map which maps from nodes in the original graph to nodes 2859 // in the new graph. 2860 llvm::SmallPtrSet<const ExplodedNode *, 32> RemainingNodes; 2861 2862 for (unsigned i = 0, count = Nodes.size(); i < count; ++i) { 2863 if (const ExplodedNode *NewNode = ForwardMap.lookup(Nodes[i])) { 2864 ReportNodes.push_back(std::make_pair(NewNode, i)); 2865 RemainingNodes.insert(NewNode); 2866 } 2867 } 2868 2869 assert(!RemainingNodes.empty() && "No error node found in the trimmed graph"); 2870 2871 // Perform a forward BFS to find all the shortest paths. 2872 std::queue<const ExplodedNode *> WS; 2873 2874 assert(G->num_roots() == 1); 2875 WS.push(*G->roots_begin()); 2876 unsigned Priority = 0; 2877 2878 while (!WS.empty()) { 2879 const ExplodedNode *Node = WS.front(); 2880 WS.pop(); 2881 2882 PriorityMapTy::iterator PriorityEntry; 2883 bool IsNew; 2884 std::tie(PriorityEntry, IsNew) = 2885 PriorityMap.insert(std::make_pair(Node, Priority)); 2886 ++Priority; 2887 2888 if (!IsNew) { 2889 assert(PriorityEntry->second <= Priority); 2890 continue; 2891 } 2892 2893 if (RemainingNodes.erase(Node)) 2894 if (RemainingNodes.empty()) 2895 break; 2896 2897 for (ExplodedNode::const_pred_iterator I = Node->succ_begin(), 2898 E = Node->succ_end(); 2899 I != E; ++I) 2900 WS.push(*I); 2901 } 2902 2903 // Sort the error paths from longest to shortest. 2904 std::sort(ReportNodes.begin(), ReportNodes.end(), 2905 PriorityCompare<true>(PriorityMap)); 2906} 2907 2908bool TrimmedGraph::popNextReportGraph(ReportGraph &GraphWrapper) { 2909 if (ReportNodes.empty()) 2910 return false; 2911 2912 const ExplodedNode *OrigN; 2913 std::tie(OrigN, GraphWrapper.Index) = ReportNodes.pop_back_val(); 2914 assert(PriorityMap.find(OrigN) != PriorityMap.end() && 2915 "error node not accessible from root"); 2916 2917 // Create a new graph with a single path. This is the graph 2918 // that will be returned to the caller. 2919 auto GNew = llvm::make_unique<ExplodedGraph>(); 2920 GraphWrapper.BackMap.clear(); 2921 2922 // Now walk from the error node up the BFS path, always taking the 2923 // predeccessor with the lowest number. 2924 ExplodedNode *Succ = nullptr; 2925 while (true) { 2926 // Create the equivalent node in the new graph with the same state 2927 // and location. 2928 ExplodedNode *NewN = GNew->getNode(OrigN->getLocation(), OrigN->getState(), 2929 OrigN->isSink()); 2930 2931 // Store the mapping to the original node. 2932 InterExplodedGraphMap::const_iterator IMitr = InverseMap.find(OrigN); 2933 assert(IMitr != InverseMap.end() && "No mapping to original node."); 2934 GraphWrapper.BackMap[NewN] = IMitr->second; 2935 2936 // Link up the new node with the previous node. 2937 if (Succ) 2938 Succ->addPredecessor(NewN, *GNew); 2939 else 2940 GraphWrapper.ErrorNode = NewN; 2941 2942 Succ = NewN; 2943 2944 // Are we at the final node? 2945 if (OrigN->pred_empty()) { 2946 GNew->addRoot(NewN); 2947 break; 2948 } 2949 2950 // Find the next predeccessor node. We choose the node that is marked 2951 // with the lowest BFS number. 2952 OrigN = *std::min_element(OrigN->pred_begin(), OrigN->pred_end(), 2953 PriorityCompare<false>(PriorityMap)); 2954 } 2955 2956 GraphWrapper.Graph = std::move(GNew); 2957 2958 return true; 2959} 2960 2961 2962/// CompactPathDiagnostic - This function postprocesses a PathDiagnostic object 2963/// and collapses PathDiagosticPieces that are expanded by macros. 2964static void CompactPathDiagnostic(PathPieces &path, const SourceManager& SM) { 2965 typedef std::vector<std::pair<IntrusiveRefCntPtr<PathDiagnosticMacroPiece>, 2966 SourceLocation> > MacroStackTy; 2967 2968 typedef std::vector<IntrusiveRefCntPtr<PathDiagnosticPiece> > 2969 PiecesTy; 2970 2971 MacroStackTy MacroStack; 2972 PiecesTy Pieces; 2973 2974 for (PathPieces::const_iterator I = path.begin(), E = path.end(); 2975 I!=E; ++I) { 2976 2977 PathDiagnosticPiece *piece = I->get(); 2978 2979 // Recursively compact calls. 2980 if (PathDiagnosticCallPiece *call=dyn_cast<PathDiagnosticCallPiece>(piece)){ 2981 CompactPathDiagnostic(call->path, SM); 2982 } 2983 2984 // Get the location of the PathDiagnosticPiece. 2985 const FullSourceLoc Loc = piece->getLocation().asLocation(); 2986 2987 // Determine the instantiation location, which is the location we group 2988 // related PathDiagnosticPieces. 2989 SourceLocation InstantiationLoc = Loc.isMacroID() ? 2990 SM.getExpansionLoc(Loc) : 2991 SourceLocation(); 2992 2993 if (Loc.isFileID()) { 2994 MacroStack.clear(); 2995 Pieces.push_back(piece); 2996 continue; 2997 } 2998 2999 assert(Loc.isMacroID()); 3000 3001 // Is the PathDiagnosticPiece within the same macro group? 3002 if (!MacroStack.empty() && InstantiationLoc == MacroStack.back().second) { 3003 MacroStack.back().first->subPieces.push_back(piece); 3004 continue; 3005 } 3006 3007 // We aren't in the same group. Are we descending into a new macro 3008 // or are part of an old one? 3009 IntrusiveRefCntPtr<PathDiagnosticMacroPiece> MacroGroup; 3010 3011 SourceLocation ParentInstantiationLoc = InstantiationLoc.isMacroID() ? 3012 SM.getExpansionLoc(Loc) : 3013 SourceLocation(); 3014 3015 // Walk the entire macro stack. 3016 while (!MacroStack.empty()) { 3017 if (InstantiationLoc == MacroStack.back().second) { 3018 MacroGroup = MacroStack.back().first; 3019 break; 3020 } 3021 3022 if (ParentInstantiationLoc == MacroStack.back().second) { 3023 MacroGroup = MacroStack.back().first; 3024 break; 3025 } 3026 3027 MacroStack.pop_back(); 3028 } 3029 3030 if (!MacroGroup || ParentInstantiationLoc == MacroStack.back().second) { 3031 // Create a new macro group and add it to the stack. 3032 PathDiagnosticMacroPiece *NewGroup = 3033 new PathDiagnosticMacroPiece( 3034 PathDiagnosticLocation::createSingleLocation(piece->getLocation())); 3035 3036 if (MacroGroup) 3037 MacroGroup->subPieces.push_back(NewGroup); 3038 else { 3039 assert(InstantiationLoc.isFileID()); 3040 Pieces.push_back(NewGroup); 3041 } 3042 3043 MacroGroup = NewGroup; 3044 MacroStack.push_back(std::make_pair(MacroGroup, InstantiationLoc)); 3045 } 3046 3047 // Finally, add the PathDiagnosticPiece to the group. 3048 MacroGroup->subPieces.push_back(piece); 3049 } 3050 3051 // Now take the pieces and construct a new PathDiagnostic. 3052 path.clear(); 3053 3054 path.insert(path.end(), Pieces.begin(), Pieces.end()); 3055} 3056 3057bool GRBugReporter::generatePathDiagnostic(PathDiagnostic& PD, 3058 PathDiagnosticConsumer &PC, 3059 ArrayRef<BugReport *> &bugReports) { 3060 assert(!bugReports.empty()); 3061 3062 bool HasValid = false; 3063 bool HasInvalid = false; 3064 SmallVector<const ExplodedNode *, 32> errorNodes; 3065 for (ArrayRef<BugReport*>::iterator I = bugReports.begin(), 3066 E = bugReports.end(); I != E; ++I) { 3067 if ((*I)->isValid()) { 3068 HasValid = true; 3069 errorNodes.push_back((*I)->getErrorNode()); 3070 } else { 3071 // Keep the errorNodes list in sync with the bugReports list. 3072 HasInvalid = true; 3073 errorNodes.push_back(nullptr); 3074 } 3075 } 3076 3077 // If all the reports have been marked invalid by a previous path generation, 3078 // we're done. 3079 if (!HasValid) 3080 return false; 3081 3082 typedef PathDiagnosticConsumer::PathGenerationScheme PathGenerationScheme; 3083 PathGenerationScheme ActiveScheme = PC.getGenerationScheme(); 3084 3085 if (ActiveScheme == PathDiagnosticConsumer::Extensive) { 3086 AnalyzerOptions &options = getAnalyzerOptions(); 3087 if (options.getBooleanOption("path-diagnostics-alternate", true)) { 3088 ActiveScheme = PathDiagnosticConsumer::AlternateExtensive; 3089 } 3090 } 3091 3092 TrimmedGraph TrimG(&getGraph(), errorNodes); 3093 ReportGraph ErrorGraph; 3094 3095 while (TrimG.popNextReportGraph(ErrorGraph)) { 3096 // Find the BugReport with the original location. 3097 assert(ErrorGraph.Index < bugReports.size()); 3098 BugReport *R = bugReports[ErrorGraph.Index]; 3099 assert(R && "No original report found for sliced graph."); 3100 assert(R->isValid() && "Report selected by trimmed graph marked invalid."); 3101 3102 // Start building the path diagnostic... 3103 PathDiagnosticBuilder PDB(*this, R, ErrorGraph.BackMap, &PC); 3104 const ExplodedNode *N = ErrorGraph.ErrorNode; 3105 3106 // Register additional node visitors. 3107 R->addVisitor(llvm::make_unique<NilReceiverBRVisitor>()); 3108 R->addVisitor(llvm::make_unique<ConditionBRVisitor>()); 3109 R->addVisitor(llvm::make_unique<LikelyFalsePositiveSuppressionBRVisitor>()); 3110 3111 BugReport::VisitorList visitors; 3112 unsigned origReportConfigToken, finalReportConfigToken; 3113 LocationContextMap LCM; 3114 3115 // While generating diagnostics, it's possible the visitors will decide 3116 // new symbols and regions are interesting, or add other visitors based on 3117 // the information they find. If they do, we need to regenerate the path 3118 // based on our new report configuration. 3119 do { 3120 // Get a clean copy of all the visitors. 3121 for (BugReport::visitor_iterator I = R->visitor_begin(), 3122 E = R->visitor_end(); I != E; ++I) 3123 visitors.push_back((*I)->clone()); 3124 3125 // Clear out the active path from any previous work. 3126 PD.resetPath(); 3127 origReportConfigToken = R->getConfigurationChangeToken(); 3128 3129 // Generate the very last diagnostic piece - the piece is visible before 3130 // the trace is expanded. 3131 std::unique_ptr<PathDiagnosticPiece> LastPiece; 3132 for (BugReport::visitor_iterator I = visitors.begin(), E = visitors.end(); 3133 I != E; ++I) { 3134 if (std::unique_ptr<PathDiagnosticPiece> Piece = 3135 (*I)->getEndPath(PDB, N, *R)) { 3136 assert (!LastPiece && 3137 "There can only be one final piece in a diagnostic."); 3138 LastPiece = std::move(Piece); 3139 } 3140 } 3141 3142 if (ActiveScheme != PathDiagnosticConsumer::None) { 3143 if (!LastPiece) 3144 LastPiece = BugReporterVisitor::getDefaultEndPath(PDB, N, *R); 3145 assert(LastPiece); 3146 PD.setEndOfPath(std::move(LastPiece)); 3147 } 3148 3149 // Make sure we get a clean location context map so we don't 3150 // hold onto old mappings. 3151 LCM.clear(); 3152 3153 switch (ActiveScheme) { 3154 case PathDiagnosticConsumer::AlternateExtensive: 3155 GenerateAlternateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 3156 break; 3157 case PathDiagnosticConsumer::Extensive: 3158 GenerateExtensivePathDiagnostic(PD, PDB, N, LCM, visitors); 3159 break; 3160 case PathDiagnosticConsumer::Minimal: 3161 GenerateMinimalPathDiagnostic(PD, PDB, N, LCM, visitors); 3162 break; 3163 case PathDiagnosticConsumer::None: 3164 GenerateVisitorsOnlyPathDiagnostic(PD, PDB, N, visitors); 3165 break; 3166 } 3167 3168 // Clean up the visitors we used. 3169 visitors.clear(); 3170 3171 // Did anything change while generating this path? 3172 finalReportConfigToken = R->getConfigurationChangeToken(); 3173 } while (finalReportConfigToken != origReportConfigToken); 3174 3175 if (!R->isValid()) 3176 continue; 3177 3178 // Finally, prune the diagnostic path of uninteresting stuff. 3179 if (!PD.path.empty()) { 3180 if (R->shouldPrunePath() && getAnalyzerOptions().shouldPrunePaths()) { 3181 bool stillHasNotes = removeUnneededCalls(PD.getMutablePieces(), R, LCM); 3182 assert(stillHasNotes); 3183 (void)stillHasNotes; 3184 } 3185 3186 // Redirect all call pieces to have valid locations. 3187 adjustCallLocations(PD.getMutablePieces()); 3188 removePiecesWithInvalidLocations(PD.getMutablePieces()); 3189 3190 if (ActiveScheme == PathDiagnosticConsumer::AlternateExtensive) { 3191 SourceManager &SM = getSourceManager(); 3192 3193 // Reduce the number of edges from a very conservative set 3194 // to an aesthetically pleasing subset that conveys the 3195 // necessary information. 3196 OptimizedCallsSet OCS; 3197 while (optimizeEdges(PD.getMutablePieces(), SM, OCS, LCM)) {} 3198 3199 // Drop the very first function-entry edge. It's not really necessary 3200 // for top-level functions. 3201 dropFunctionEntryEdge(PD.getMutablePieces(), LCM, SM); 3202 } 3203 3204 // Remove messages that are basically the same, and edges that may not 3205 // make sense. 3206 // We have to do this after edge optimization in the Extensive mode. 3207 removeRedundantMsgs(PD.getMutablePieces()); 3208 removeEdgesToDefaultInitializers(PD.getMutablePieces()); 3209 } 3210 3211 // We found a report and didn't suppress it. 3212 return true; 3213 } 3214 3215 // We suppressed all the reports in this equivalence class. 3216 assert(!HasInvalid && "Inconsistent suppression"); 3217 (void)HasInvalid; 3218 return false; 3219} 3220 3221void BugReporter::Register(BugType *BT) { 3222 BugTypes = F.add(BugTypes, BT); 3223} 3224 3225void BugReporter::emitReport(std::unique_ptr<BugReport> R) { 3226 if (const ExplodedNode *E = R->getErrorNode()) { 3227 const AnalysisDeclContext *DeclCtx = 3228 E->getLocationContext()->getAnalysisDeclContext(); 3229 // The source of autosynthesized body can be handcrafted AST or a model 3230 // file. The locations from handcrafted ASTs have no valid source locations 3231 // and have to be discarded. Locations from model files should be preserved 3232 // for processing and reporting. 3233 if (DeclCtx->isBodyAutosynthesized() && 3234 !DeclCtx->isBodyAutosynthesizedFromModelFile()) 3235 return; 3236 } 3237 3238 bool ValidSourceLoc = R->getLocation(getSourceManager()).isValid(); 3239 assert(ValidSourceLoc); 3240 // If we mess up in a release build, we'd still prefer to just drop the bug 3241 // instead of trying to go on. 3242 if (!ValidSourceLoc) 3243 return; 3244 3245 // Compute the bug report's hash to determine its equivalence class. 3246 llvm::FoldingSetNodeID ID; 3247 R->Profile(ID); 3248 3249 // Lookup the equivance class. If there isn't one, create it. 3250 BugType& BT = R->getBugType(); 3251 Register(&BT); 3252 void *InsertPos; 3253 BugReportEquivClass* EQ = EQClasses.FindNodeOrInsertPos(ID, InsertPos); 3254 3255 if (!EQ) { 3256 EQ = new BugReportEquivClass(std::move(R)); 3257 EQClasses.InsertNode(EQ, InsertPos); 3258 EQClassesVector.push_back(EQ); 3259 } else 3260 EQ->AddReport(std::move(R)); 3261} 3262 3263 3264//===----------------------------------------------------------------------===// 3265// Emitting reports in equivalence classes. 3266//===----------------------------------------------------------------------===// 3267 3268namespace { 3269struct FRIEC_WLItem { 3270 const ExplodedNode *N; 3271 ExplodedNode::const_succ_iterator I, E; 3272 3273 FRIEC_WLItem(const ExplodedNode *n) 3274 : N(n), I(N->succ_begin()), E(N->succ_end()) {} 3275}; 3276} 3277 3278static BugReport * 3279FindReportInEquivalenceClass(BugReportEquivClass& EQ, 3280 SmallVectorImpl<BugReport*> &bugReports) { 3281 3282 BugReportEquivClass::iterator I = EQ.begin(), E = EQ.end(); 3283 assert(I != E); 3284 BugType& BT = I->getBugType(); 3285 3286 // If we don't need to suppress any of the nodes because they are 3287 // post-dominated by a sink, simply add all the nodes in the equivalence class 3288 // to 'Nodes'. Any of the reports will serve as a "representative" report. 3289 if (!BT.isSuppressOnSink()) { 3290 BugReport *R = I; 3291 for (BugReportEquivClass::iterator I=EQ.begin(), E=EQ.end(); I!=E; ++I) { 3292 const ExplodedNode *N = I->getErrorNode(); 3293 if (N) { 3294 R = I; 3295 bugReports.push_back(R); 3296 } 3297 } 3298 return R; 3299 } 3300 3301 // For bug reports that should be suppressed when all paths are post-dominated 3302 // by a sink node, iterate through the reports in the equivalence class 3303 // until we find one that isn't post-dominated (if one exists). We use a 3304 // DFS traversal of the ExplodedGraph to find a non-sink node. We could write 3305 // this as a recursive function, but we don't want to risk blowing out the 3306 // stack for very long paths. 3307 BugReport *exampleReport = nullptr; 3308 3309 for (; I != E; ++I) { 3310 const ExplodedNode *errorNode = I->getErrorNode(); 3311 3312 if (!errorNode) 3313 continue; 3314 if (errorNode->isSink()) { 3315 llvm_unreachable( 3316 "BugType::isSuppressSink() should not be 'true' for sink end nodes"); 3317 } 3318 // No successors? By definition this nodes isn't post-dominated by a sink. 3319 if (errorNode->succ_empty()) { 3320 bugReports.push_back(I); 3321 if (!exampleReport) 3322 exampleReport = I; 3323 continue; 3324 } 3325 3326 // At this point we know that 'N' is not a sink and it has at least one 3327 // successor. Use a DFS worklist to find a non-sink end-of-path node. 3328 typedef FRIEC_WLItem WLItem; 3329 typedef SmallVector<WLItem, 10> DFSWorkList; 3330 llvm::DenseMap<const ExplodedNode *, unsigned> Visited; 3331 3332 DFSWorkList WL; 3333 WL.push_back(errorNode); 3334 Visited[errorNode] = 1; 3335 3336 while (!WL.empty()) { 3337 WLItem &WI = WL.back(); 3338 assert(!WI.N->succ_empty()); 3339 3340 for (; WI.I != WI.E; ++WI.I) { 3341 const ExplodedNode *Succ = *WI.I; 3342 // End-of-path node? 3343 if (Succ->succ_empty()) { 3344 // If we found an end-of-path node that is not a sink. 3345 if (!Succ->isSink()) { 3346 bugReports.push_back(I); 3347 if (!exampleReport) 3348 exampleReport = I; 3349 WL.clear(); 3350 break; 3351 } 3352 // Found a sink? Continue on to the next successor. 3353 continue; 3354 } 3355 // Mark the successor as visited. If it hasn't been explored, 3356 // enqueue it to the DFS worklist. 3357 unsigned &mark = Visited[Succ]; 3358 if (!mark) { 3359 mark = 1; 3360 WL.push_back(Succ); 3361 break; 3362 } 3363 } 3364 3365 // The worklist may have been cleared at this point. First 3366 // check if it is empty before checking the last item. 3367 if (!WL.empty() && &WL.back() == &WI) 3368 WL.pop_back(); 3369 } 3370 } 3371 3372 // ExampleReport will be NULL if all the nodes in the equivalence class 3373 // were post-dominated by sinks. 3374 return exampleReport; 3375} 3376 3377void BugReporter::FlushReport(BugReportEquivClass& EQ) { 3378 SmallVector<BugReport*, 10> bugReports; 3379 BugReport *exampleReport = FindReportInEquivalenceClass(EQ, bugReports); 3380 if (exampleReport) { 3381 for (PathDiagnosticConsumer *PDC : getPathDiagnosticConsumers()) { 3382 FlushReport(exampleReport, *PDC, bugReports); 3383 } 3384 } 3385} 3386 3387void BugReporter::FlushReport(BugReport *exampleReport, 3388 PathDiagnosticConsumer &PD, 3389 ArrayRef<BugReport*> bugReports) { 3390 3391 // FIXME: Make sure we use the 'R' for the path that was actually used. 3392 // Probably doesn't make a difference in practice. 3393 BugType& BT = exampleReport->getBugType(); 3394 3395 std::unique_ptr<PathDiagnostic> D(new PathDiagnostic( 3396 exampleReport->getBugType().getCheckName(), 3397 exampleReport->getDeclWithIssue(), exampleReport->getBugType().getName(), 3398 exampleReport->getDescription(), 3399 exampleReport->getShortDescription(/*Fallback=*/false), BT.getCategory(), 3400 exampleReport->getUniqueingLocation(), 3401 exampleReport->getUniqueingDecl())); 3402 3403 MaxBugClassSize = std::max(bugReports.size(), 3404 static_cast<size_t>(MaxBugClassSize)); 3405 3406 // Generate the full path diagnostic, using the generation scheme 3407 // specified by the PathDiagnosticConsumer. Note that we have to generate 3408 // path diagnostics even for consumers which do not support paths, because 3409 // the BugReporterVisitors may mark this bug as a false positive. 3410 if (!bugReports.empty()) 3411 if (!generatePathDiagnostic(*D.get(), PD, bugReports)) 3412 return; 3413 3414 MaxValidBugClassSize = std::max(bugReports.size(), 3415 static_cast<size_t>(MaxValidBugClassSize)); 3416 3417 // Examine the report and see if the last piece is in a header. Reset the 3418 // report location to the last piece in the main source file. 3419 AnalyzerOptions& Opts = getAnalyzerOptions(); 3420 if (Opts.shouldReportIssuesInMainSourceFile() && !Opts.AnalyzeAll) 3421 D->resetDiagnosticLocationToMainFile(); 3422 3423 // If the path is empty, generate a single step path with the location 3424 // of the issue. 3425 if (D->path.empty()) { 3426 PathDiagnosticLocation L = exampleReport->getLocation(getSourceManager()); 3427 auto piece = llvm::make_unique<PathDiagnosticEventPiece>( 3428 L, exampleReport->getDescription()); 3429 for (const SourceRange &Range : exampleReport->getRanges()) 3430 piece->addRange(Range); 3431 D->setEndOfPath(std::move(piece)); 3432 } 3433 3434 // Get the meta data. 3435 const BugReport::ExtraTextList &Meta = exampleReport->getExtraText(); 3436 for (BugReport::ExtraTextList::const_iterator i = Meta.begin(), 3437 e = Meta.end(); i != e; ++i) { 3438 D->addMeta(*i); 3439 } 3440 3441 PD.HandlePathDiagnostic(std::move(D)); 3442} 3443 3444void BugReporter::EmitBasicReport(const Decl *DeclWithIssue, 3445 const CheckerBase *Checker, 3446 StringRef Name, StringRef Category, 3447 StringRef Str, PathDiagnosticLocation Loc, 3448 ArrayRef<SourceRange> Ranges) { 3449 EmitBasicReport(DeclWithIssue, Checker->getCheckName(), Name, Category, Str, 3450 Loc, Ranges); 3451} 3452void BugReporter::EmitBasicReport(const Decl *DeclWithIssue, 3453 CheckName CheckName, 3454 StringRef name, StringRef category, 3455 StringRef str, PathDiagnosticLocation Loc, 3456 ArrayRef<SourceRange> Ranges) { 3457 3458 // 'BT' is owned by BugReporter. 3459 BugType *BT = getBugTypeForName(CheckName, name, category); 3460 auto R = llvm::make_unique<BugReport>(*BT, str, Loc); 3461 R->setDeclWithIssue(DeclWithIssue); 3462 for (ArrayRef<SourceRange>::iterator I = Ranges.begin(), E = Ranges.end(); 3463 I != E; ++I) 3464 R->addRange(*I); 3465 emitReport(std::move(R)); 3466} 3467 3468BugType *BugReporter::getBugTypeForName(CheckName CheckName, StringRef name, 3469 StringRef category) { 3470 SmallString<136> fullDesc; 3471 llvm::raw_svector_ostream(fullDesc) << CheckName.getName() << ":" << name 3472 << ":" << category; 3473 BugType *&BT = StrBugTypes[fullDesc]; 3474 if (!BT) 3475 BT = new BugType(CheckName, name, category); 3476 return BT; 3477} 3478 3479LLVM_DUMP_METHOD void PathPieces::dump() const { 3480 unsigned index = 0; 3481 for (PathPieces::const_iterator I = begin(), E = end(); I != E; ++I) { 3482 llvm::errs() << "[" << index++ << "] "; 3483 (*I)->dump(); 3484 llvm::errs() << "\n"; 3485 } 3486} 3487 3488void PathDiagnosticCallPiece::dump() const { 3489 llvm::errs() << "CALL\n--------------\n"; 3490 3491 if (const Stmt *SLoc = getLocStmt(getLocation())) 3492 SLoc->dump(); 3493 else if (const NamedDecl *ND = dyn_cast<NamedDecl>(getCallee())) 3494 llvm::errs() << *ND << "\n"; 3495 else 3496 getLocation().dump(); 3497} 3498 3499void PathDiagnosticEventPiece::dump() const { 3500 llvm::errs() << "EVENT\n--------------\n"; 3501 llvm::errs() << getString() << "\n"; 3502 llvm::errs() << " ---- at ----\n"; 3503 getLocation().dump(); 3504} 3505 3506void PathDiagnosticControlFlowPiece::dump() const { 3507 llvm::errs() << "CONTROL\n--------------\n"; 3508 getStartLocation().dump(); 3509 llvm::errs() << " ---- to ----\n"; 3510 getEndLocation().dump(); 3511} 3512 3513void PathDiagnosticMacroPiece::dump() const { 3514 llvm::errs() << "MACRO\n--------------\n"; 3515 // FIXME: Print which macro is being invoked. 3516} 3517 3518void PathDiagnosticLocation::dump() const { 3519 if (!isValid()) { 3520 llvm::errs() << "<INVALID>\n"; 3521 return; 3522 } 3523 3524 switch (K) { 3525 case RangeK: 3526 // FIXME: actually print the range. 3527 llvm::errs() << "<range>\n"; 3528 break; 3529 case SingleLocK: 3530 asLocation().dump(); 3531 llvm::errs() << "\n"; 3532 break; 3533 case StmtK: 3534 if (S) 3535 S->dump(); 3536 else 3537 llvm::errs() << "<NULL STMT>\n"; 3538 break; 3539 case DeclK: 3540 if (const NamedDecl *ND = dyn_cast_or_null<NamedDecl>(D)) 3541 llvm::errs() << *ND << "\n"; 3542 else if (isa<BlockDecl>(D)) 3543 // FIXME: Make this nicer. 3544 llvm::errs() << "<block>\n"; 3545 else if (D) 3546 llvm::errs() << "<unknown decl>\n"; 3547 else 3548 llvm::errs() << "<NULL DECL>\n"; 3549 break; 3550 } 3551} 3552