CFG.cpp revision a1898ddd5d0e46330898930b9185b628b5cede63
1//===--- CFG.cpp - Classes for representing and building CFGs----*- 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 the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39class AddStmtChoice { 40public: 41 enum Kind { NotAlwaysAdd = 0, 42 AlwaysAdd = 1, 43 AsLValueNotAlwaysAdd = 2, 44 AlwaysAddAsLValue = 3 }; 45 46 AddStmtChoice(Kind kind) : k(kind) {} 47 48 bool alwaysAdd() const { return (unsigned)k & 0x1; } 49 bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } 50 51private: 52 Kind k; 53}; 54 55/// LocalScope - Node in tree of local scopes created for C++ implicit 56/// destructor calls generation. It contains list of automatic variables 57/// declared in the scope and link to position in previous scope this scope 58/// began in. 59/// 60/// The process of creating local scopes is as follows: 61/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 62/// - Before processing statements in scope (e.g. CompoundStmt) create 63/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 64/// and set CFGBuilder::ScopePos to the end of new scope, 65/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 66/// at this VarDecl, 67/// - For every normal (without jump) end of scope add to CFGBlock destructors 68/// for objects in the current scope, 69/// - For every jump add to CFGBlock destructors for objects 70/// between CFGBuilder::ScopePos and local scope position saved for jump 71/// target. Thanks to C++ restrictions on goto jumps we can be sure that 72/// jump target position will be on the path to root from CFGBuilder::ScopePos 73/// (adding any variable that doesn't need constructor to be called to 74/// LocalScope can break this assumption), 75/// 76class LocalScope { 77public: 78 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 79 80 /// const_iterator - Iterates local scope backwards and jumps to previous 81 /// scope on reaching the beginning of currently iterated scope. 82 class const_iterator { 83 const LocalScope* Scope; 84 85 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 86 /// Invalid iterator (with null Scope) has VarIter equal to 0. 87 unsigned VarIter; 88 89 public: 90 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 91 /// Incrementing invalid iterator is allowed and will result in invalid 92 /// iterator. 93 const_iterator() 94 : Scope(NULL), VarIter(0) {} 95 96 /// Create valid iterator. In case when S.Prev is an invalid iterator and 97 /// I is equal to 0, this will create invalid iterator. 98 const_iterator(const LocalScope& S, unsigned I) 99 : Scope(&S), VarIter(I) { 100 // Iterator to "end" of scope is not allowed. Handle it by going up 101 // in scopes tree possibly up to invalid iterator in the root. 102 if (VarIter == 0 && Scope) 103 *this = Scope->Prev; 104 } 105 106 VarDecl* const* operator->() const { 107 assert (Scope && "Dereferencing invalid iterator is not allowed"); 108 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 109 return &Scope->Vars[VarIter - 1]; 110 } 111 VarDecl* operator*() const { 112 return *this->operator->(); 113 } 114 115 const_iterator& operator++() { 116 if (!Scope) 117 return *this; 118 119 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 120 --VarIter; 121 if (VarIter == 0) 122 *this = Scope->Prev; 123 return *this; 124 } 125 const_iterator operator++(int) { 126 const_iterator P = *this; 127 ++*this; 128 return P; 129 } 130 131 bool operator==(const const_iterator& rhs) const { 132 return Scope == rhs.Scope && VarIter == rhs.VarIter; 133 } 134 bool operator!=(const const_iterator& rhs) const { 135 return !(*this == rhs); 136 } 137 138 operator bool() const { 139 return *this != const_iterator(); 140 } 141 142 int distance(const_iterator L); 143 }; 144 145 friend class const_iterator; 146 147private: 148 /// Automatic variables in order of declaration. 149 AutomaticVarsTy Vars; 150 /// Iterator to variable in previous scope that was declared just before 151 /// begin of this scope. 152 const_iterator Prev; 153 154public: 155 /// Constructs empty scope linked to previous scope in specified place. 156 LocalScope(const_iterator P) 157 : Vars() 158 , Prev(P) {} 159 160 /// Begin of scope in direction of CFG building (backwards). 161 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 162 163 void addVar(VarDecl* VD) { 164 Vars.push_back(VD); 165 } 166}; 167 168/// distance - Calculates distance from this to L. L must be reachable from this 169/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 170/// number of scopes between this and L. 171int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 172 int D = 0; 173 const_iterator F = *this; 174 while (F.Scope != L.Scope) { 175 assert (F != const_iterator() 176 && "L iterator is not reachable from F iterator."); 177 D += F.VarIter; 178 F = F.Scope->Prev; 179 } 180 D += F.VarIter - L.VarIter; 181 return D; 182} 183 184/// BlockScopePosPair - Structure for specifying position in CFG during its 185/// build process. It consists of CFGBlock that specifies position in CFG graph 186/// and LocalScope::const_iterator that specifies position in LocalScope graph. 187struct BlockScopePosPair { 188 BlockScopePosPair() {} 189 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 190 : Block(B), ScopePos(S) {} 191 192 CFGBlock* Block; 193 LocalScope::const_iterator ScopePos; 194}; 195 196/// CFGBuilder - This class implements CFG construction from an AST. 197/// The builder is stateful: an instance of the builder should be used to only 198/// construct a single CFG. 199/// 200/// Example usage: 201/// 202/// CFGBuilder builder; 203/// CFG* cfg = builder.BuildAST(stmt1); 204/// 205/// CFG construction is done via a recursive walk of an AST. We actually parse 206/// the AST in reverse order so that the successor of a basic block is 207/// constructed prior to its predecessor. This allows us to nicely capture 208/// implicit fall-throughs without extra basic blocks. 209/// 210class CFGBuilder { 211 typedef BlockScopePosPair JumpTarget; 212 typedef BlockScopePosPair JumpSource; 213 214 ASTContext *Context; 215 llvm::OwningPtr<CFG> cfg; 216 217 CFGBlock* Block; 218 CFGBlock* Succ; 219 JumpTarget ContinueJumpTarget; 220 JumpTarget BreakJumpTarget; 221 CFGBlock* SwitchTerminatedBlock; 222 CFGBlock* DefaultCaseBlock; 223 CFGBlock* TryTerminatedBlock; 224 225 // Current position in local scope. 226 LocalScope::const_iterator ScopePos; 227 228 // LabelMap records the mapping from Label expressions to their jump targets. 229 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 230 LabelMapTy LabelMap; 231 232 // A list of blocks that end with a "goto" that must be backpatched to their 233 // resolved targets upon completion of CFG construction. 234 typedef std::vector<JumpSource> BackpatchBlocksTy; 235 BackpatchBlocksTy BackpatchBlocks; 236 237 // A list of labels whose address has been taken (for indirect gotos). 238 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 239 LabelSetTy AddressTakenLabels; 240 241 bool badCFG; 242 CFG::BuildOptions BuildOpts; 243 244public: 245 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 246 Block(NULL), Succ(NULL), 247 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 248 TryTerminatedBlock(NULL), badCFG(false) {} 249 250 // buildCFG - Used by external clients to construct the CFG. 251 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 252 CFG::BuildOptions BO); 253 254private: 255 // Visitors to walk an AST and construct the CFG. 256 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 257 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 258 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 259 CFGBlock *VisitBreakStmt(BreakStmt *B); 260 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 261 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 262 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 263 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 264 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 265 CFGBlock *VisitCaseStmt(CaseStmt *C); 266 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 267 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 268 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 269 CFGBlock *VisitContinueStmt(ContinueStmt *C); 270 CFGBlock *VisitDeclStmt(DeclStmt *DS); 271 CFGBlock *VisitDeclSubExpr(Decl* D); 272 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 273 CFGBlock *VisitDoStmt(DoStmt *D); 274 CFGBlock *VisitForStmt(ForStmt *F); 275 CFGBlock *VisitGotoStmt(GotoStmt* G); 276 CFGBlock *VisitIfStmt(IfStmt *I); 277 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 278 CFGBlock *VisitLabelStmt(LabelStmt *L); 279 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 280 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 281 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 282 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 283 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 284 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 285 CFGBlock *VisitReturnStmt(ReturnStmt* R); 286 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 287 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 288 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 289 CFGBlock *VisitWhileStmt(WhileStmt *W); 290 291 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 292 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 293 CFGBlock *VisitChildren(Stmt* S); 294 295 // NYS == Not Yet Supported 296 CFGBlock* NYS() { 297 badCFG = true; 298 return Block; 299 } 300 301 void autoCreateBlock() { if (!Block) Block = createBlock(); } 302 CFGBlock *createBlock(bool add_successor = true); 303 304 CFGBlock *addStmt(Stmt *S) { 305 return Visit(S, AddStmtChoice::AlwaysAdd); 306 } 307 CFGBlock *addInitializer(CXXBaseOrMemberInitializer *I); 308 void addAutomaticObjDtors(LocalScope::const_iterator B, 309 LocalScope::const_iterator E, Stmt* S); 310 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 311 312 // Local scopes creation. 313 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 314 315 void addLocalScopeForStmt(Stmt* S); 316 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 317 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 318 319 void addLocalScopeAndDtors(Stmt* S); 320 321 // Interface to CFGBlock - adding CFGElements. 322 void AppendStmt(CFGBlock *B, Stmt *S, 323 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 324 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 325 } 326 void appendInitializer(CFGBlock *B, CXXBaseOrMemberInitializer *I) { 327 B->appendInitializer(I, cfg->getBumpVectorContext()); 328 } 329 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 330 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 331 } 332 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 333 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 334 } 335 336 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 337 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 338 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 339 LocalScope::const_iterator E, Stmt* S); 340 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 341 LocalScope::const_iterator B, LocalScope::const_iterator E); 342 343 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 344 B->addSuccessor(S, cfg->getBumpVectorContext()); 345 } 346 347 /// TryResult - a class representing a variant over the values 348 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 349 /// and is used by the CFGBuilder to decide if a branch condition 350 /// can be decided up front during CFG construction. 351 class TryResult { 352 int X; 353 public: 354 TryResult(bool b) : X(b ? 1 : 0) {} 355 TryResult() : X(-1) {} 356 357 bool isTrue() const { return X == 1; } 358 bool isFalse() const { return X == 0; } 359 bool isKnown() const { return X >= 0; } 360 void negate() { 361 assert(isKnown()); 362 X ^= 0x1; 363 } 364 }; 365 366 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 367 /// if we can evaluate to a known value, otherwise return -1. 368 TryResult TryEvaluateBool(Expr *S) { 369 if (!BuildOpts.PruneTriviallyFalseEdges) 370 return TryResult(); 371 372 Expr::EvalResult Result; 373 if (!S->isTypeDependent() && !S->isValueDependent() && 374 S->Evaluate(Result, *Context) && Result.Val.isInt()) 375 return Result.Val.getInt().getBoolValue(); 376 377 return TryResult(); 378 } 379}; 380 381// FIXME: Add support for dependent-sized array types in C++? 382// Does it even make sense to build a CFG for an uninstantiated template? 383static VariableArrayType* FindVA(Type* t) { 384 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 385 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 386 if (vat->getSizeExpr()) 387 return vat; 388 389 t = vt->getElementType().getTypePtr(); 390 } 391 392 return 0; 393} 394 395/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 396/// arbitrary statement. Examples include a single expression or a function 397/// body (compound statement). The ownership of the returned CFG is 398/// transferred to the caller. If CFG construction fails, this method returns 399/// NULL. 400CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 401 CFG::BuildOptions BO) { 402 403 Context = C; 404 assert(cfg.get()); 405 if (!Statement) 406 return NULL; 407 408 BuildOpts = BO; 409 410 // Create an empty block that will serve as the exit block for the CFG. Since 411 // this is the first block added to the CFG, it will be implicitly registered 412 // as the exit block. 413 Succ = createBlock(); 414 assert(Succ == &cfg->getExit()); 415 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 416 417 if (BuildOpts.AddImplicitDtors) 418 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 419 addImplicitDtorsForDestructor(DD); 420 421 // Visit the statements and create the CFG. 422 CFGBlock *B = addStmt(Statement); 423 424 if (badCFG) 425 return NULL; 426 427 // For C++ constructor add initializers to CFG. 428 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 429 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 430 E = CD->init_rend(); I != E; ++I) { 431 B = addInitializer(*I); 432 if (badCFG) 433 return NULL; 434 } 435 } 436 437 if (B) 438 Succ = B; 439 440 // Backpatch the gotos whose label -> block mappings we didn't know when we 441 // encountered them. 442 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 443 E = BackpatchBlocks.end(); I != E; ++I ) { 444 445 CFGBlock* B = I->Block; 446 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 447 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 448 449 // If there is no target for the goto, then we are looking at an 450 // incomplete AST. Handle this by not registering a successor. 451 if (LI == LabelMap.end()) continue; 452 453 JumpTarget JT = LI->second; 454 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 455 AddSuccessor(B, JT.Block); 456 } 457 458 // Add successors to the Indirect Goto Dispatch block (if we have one). 459 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 460 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 461 E = AddressTakenLabels.end(); I != E; ++I ) { 462 463 // Lookup the target block. 464 LabelMapTy::iterator LI = LabelMap.find(*I); 465 466 // If there is no target block that contains label, then we are looking 467 // at an incomplete AST. Handle this by not registering a successor. 468 if (LI == LabelMap.end()) continue; 469 470 AddSuccessor(B, LI->second.Block); 471 } 472 473 // Create an empty entry block that has no predecessors. 474 cfg->setEntry(createBlock()); 475 476 return cfg.take(); 477} 478 479/// createBlock - Used to lazily create blocks that are connected 480/// to the current (global) succcessor. 481CFGBlock* CFGBuilder::createBlock(bool add_successor) { 482 CFGBlock* B = cfg->createBlock(); 483 if (add_successor && Succ) 484 AddSuccessor(B, Succ); 485 return B; 486} 487 488/// addInitializer - Add C++ base or member initializer element to CFG. 489CFGBlock *CFGBuilder::addInitializer(CXXBaseOrMemberInitializer *I) { 490 if (!BuildOpts.AddInitializers) 491 return Block; 492 493 autoCreateBlock(); 494 appendInitializer(Block, I); 495 496 if (Expr *Init = I->getInit()) { 497 AddStmtChoice::Kind K = AddStmtChoice::NotAlwaysAdd; 498 if (FieldDecl *FD = I->getMember()) 499 if (FD->getType()->isReferenceType()) 500 K = AddStmtChoice::AsLValueNotAlwaysAdd; 501 502 return Visit(Init, AddStmtChoice(K)); 503 } 504 505 return Block; 506} 507 508/// addAutomaticObjDtors - Add to current block automatic objects destructors 509/// for objects in range of local scope positions. Use S as trigger statement 510/// for destructors. 511void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 512 LocalScope::const_iterator E, Stmt* S) { 513 if (!BuildOpts.AddImplicitDtors) 514 return; 515 516 if (B == E) 517 return; 518 519 autoCreateBlock(); 520 appendAutomaticObjDtors(Block, B, E, S); 521} 522 523/// addImplicitDtorsForDestructor - Add implicit destructors generated for 524/// base and member objects in destructor. 525void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 526 assert (BuildOpts.AddImplicitDtors 527 && "Can be called only when dtors should be added"); 528 const CXXRecordDecl *RD = DD->getParent(); 529 530 // At the end destroy virtual base objects. 531 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 532 VE = RD->vbases_end(); VI != VE; ++VI) { 533 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 534 if (!CD->hasTrivialDestructor()) { 535 autoCreateBlock(); 536 appendBaseDtor(Block, VI); 537 } 538 } 539 540 // Before virtual bases destroy direct base objects. 541 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 542 BE = RD->bases_end(); BI != BE; ++BI) { 543 if (!BI->isVirtual()) { 544 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 545 if (!CD->hasTrivialDestructor()) { 546 autoCreateBlock(); 547 appendBaseDtor(Block, BI); 548 } 549 } 550 } 551 552 // First destroy member objects. 553 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 554 FE = RD->field_end(); FI != FE; ++FI) { 555 // Check for constant size array. Set type to array element type. 556 QualType QT = FI->getType(); 557 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 558 if (AT->getSize() == 0) 559 continue; 560 QT = AT->getElementType(); 561 } 562 563 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 564 if (!CD->hasTrivialDestructor()) { 565 autoCreateBlock(); 566 appendMemberDtor(Block, *FI); 567 } 568 } 569} 570 571/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 572/// way return valid LocalScope object. 573LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 574 if (!Scope) { 575 Scope = cfg->getAllocator().Allocate<LocalScope>(); 576 new (Scope) LocalScope(ScopePos); 577 } 578 return Scope; 579} 580 581/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 582/// that should create implicit scope (e.g. if/else substatements). 583void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 584 if (!BuildOpts.AddImplicitDtors) 585 return; 586 587 LocalScope *Scope = 0; 588 589 // For compound statement we will be creating explicit scope. 590 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 591 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 592 ; BI != BE; ++BI) { 593 Stmt* SI = *BI; 594 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 595 SI = LS->getSubStmt(); 596 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 597 Scope = addLocalScopeForDeclStmt(DS, Scope); 598 } 599 return; 600 } 601 602 // For any other statement scope will be implicit and as such will be 603 // interesting only for DeclStmt. 604 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 605 S = LS->getSubStmt(); 606 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 607 addLocalScopeForDeclStmt(DS); 608} 609 610/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 611/// reuse Scope if not NULL. 612LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 613 LocalScope* Scope) { 614 if (!BuildOpts.AddImplicitDtors) 615 return Scope; 616 617 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 618 ; DI != DE; ++DI) { 619 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 620 Scope = addLocalScopeForVarDecl(VD, Scope); 621 } 622 return Scope; 623} 624 625/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 626/// create add scope for automatic objects and temporary objects bound to 627/// const reference. Will reuse Scope if not NULL. 628LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 629 LocalScope* Scope) { 630 if (!BuildOpts.AddImplicitDtors) 631 return Scope; 632 633 // Check if variable is local. 634 switch (VD->getStorageClass()) { 635 case SC_None: 636 case SC_Auto: 637 case SC_Register: 638 break; 639 default: return Scope; 640 } 641 642 // Check for const references bound to temporary. Set type to pointee. 643 QualType QT = VD->getType(); 644 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 645 QT = RT->getPointeeType(); 646 if (!QT.isConstQualified()) 647 return Scope; 648 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 649 return Scope; 650 } 651 652 // Check for constant size array. Set type to array element type. 653 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 654 if (AT->getSize() == 0) 655 return Scope; 656 QT = AT->getElementType(); 657 } 658 659 // Check if type is a C++ class with non-trivial destructor. 660 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 661 if (!CD->hasTrivialDestructor()) { 662 // Add the variable to scope 663 Scope = createOrReuseLocalScope(Scope); 664 Scope->addVar(VD); 665 ScopePos = Scope->begin(); 666 } 667 return Scope; 668} 669 670/// addLocalScopeAndDtors - For given statement add local scope for it and 671/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 672void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 673 if (!BuildOpts.AddImplicitDtors) 674 return; 675 676 LocalScope::const_iterator scopeBeginPos = ScopePos; 677 addLocalScopeForStmt(S); 678 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 679} 680 681/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 682/// automatic storage duration to CFGBlock's elements vector. Insertion will be 683/// performed in place specified with iterator. 684void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 685 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 686 BumpVectorContext& C = cfg->getBumpVectorContext(); 687 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 688 while (B != E) 689 I = Blk->insertAutomaticObjDtor(I, *B++, S); 690} 691 692/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 693/// automatic storage duration to CFGBlock's elements vector. Elements will be 694/// appended to physical end of the vector which happens to be logical 695/// beginning. 696void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 697 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 698 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 699} 700 701/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 702/// variables with automatic storage duration to CFGBlock's elements vector. 703/// Elements will be prepended to physical beginning of the vector which 704/// happens to be logical end. Use blocks terminator as statement that specifies 705/// destructors call site. 706void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 707 LocalScope::const_iterator B, LocalScope::const_iterator E) { 708 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 709} 710 711/// Visit - Walk the subtree of a statement and add extra 712/// blocks for ternary operators, &&, and ||. We also process "," and 713/// DeclStmts (which may contain nested control-flow). 714CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 715tryAgain: 716 if (!S) { 717 badCFG = true; 718 return 0; 719 } 720 switch (S->getStmtClass()) { 721 default: 722 return VisitStmt(S, asc); 723 724 case Stmt::AddrLabelExprClass: 725 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 726 727 case Stmt::BinaryOperatorClass: 728 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 729 730 case Stmt::BlockExprClass: 731 return VisitBlockExpr(cast<BlockExpr>(S), asc); 732 733 case Stmt::BreakStmtClass: 734 return VisitBreakStmt(cast<BreakStmt>(S)); 735 736 case Stmt::CallExprClass: 737 case Stmt::CXXOperatorCallExprClass: 738 return VisitCallExpr(cast<CallExpr>(S), asc); 739 740 case Stmt::CaseStmtClass: 741 return VisitCaseStmt(cast<CaseStmt>(S)); 742 743 case Stmt::ChooseExprClass: 744 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 745 746 case Stmt::CompoundStmtClass: 747 return VisitCompoundStmt(cast<CompoundStmt>(S)); 748 749 case Stmt::ConditionalOperatorClass: 750 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 751 752 case Stmt::ContinueStmtClass: 753 return VisitContinueStmt(cast<ContinueStmt>(S)); 754 755 case Stmt::CXXCatchStmtClass: 756 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 757 758 case Stmt::CXXExprWithTemporariesClass: { 759 // FIXME: Handle temporaries. For now, just visit the subexpression 760 // so we don't artificially create extra blocks. 761 return Visit(cast<CXXExprWithTemporaries>(S)->getSubExpr(), asc); 762 } 763 764 case Stmt::CXXMemberCallExprClass: 765 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 766 767 case Stmt::CXXThrowExprClass: 768 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 769 770 case Stmt::CXXTryStmtClass: 771 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 772 773 case Stmt::DeclStmtClass: 774 return VisitDeclStmt(cast<DeclStmt>(S)); 775 776 case Stmt::DefaultStmtClass: 777 return VisitDefaultStmt(cast<DefaultStmt>(S)); 778 779 case Stmt::DoStmtClass: 780 return VisitDoStmt(cast<DoStmt>(S)); 781 782 case Stmt::ForStmtClass: 783 return VisitForStmt(cast<ForStmt>(S)); 784 785 case Stmt::GotoStmtClass: 786 return VisitGotoStmt(cast<GotoStmt>(S)); 787 788 case Stmt::IfStmtClass: 789 return VisitIfStmt(cast<IfStmt>(S)); 790 791 case Stmt::IndirectGotoStmtClass: 792 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 793 794 case Stmt::LabelStmtClass: 795 return VisitLabelStmt(cast<LabelStmt>(S)); 796 797 case Stmt::MemberExprClass: 798 return VisitMemberExpr(cast<MemberExpr>(S), asc); 799 800 case Stmt::ObjCAtCatchStmtClass: 801 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 802 803 case Stmt::ObjCAtSynchronizedStmtClass: 804 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 805 806 case Stmt::ObjCAtThrowStmtClass: 807 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 808 809 case Stmt::ObjCAtTryStmtClass: 810 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 811 812 case Stmt::ObjCForCollectionStmtClass: 813 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 814 815 case Stmt::ParenExprClass: 816 S = cast<ParenExpr>(S)->getSubExpr(); 817 goto tryAgain; 818 819 case Stmt::NullStmtClass: 820 return Block; 821 822 case Stmt::ReturnStmtClass: 823 return VisitReturnStmt(cast<ReturnStmt>(S)); 824 825 case Stmt::SizeOfAlignOfExprClass: 826 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 827 828 case Stmt::StmtExprClass: 829 return VisitStmtExpr(cast<StmtExpr>(S), asc); 830 831 case Stmt::SwitchStmtClass: 832 return VisitSwitchStmt(cast<SwitchStmt>(S)); 833 834 case Stmt::WhileStmtClass: 835 return VisitWhileStmt(cast<WhileStmt>(S)); 836 } 837} 838 839CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 840 if (asc.alwaysAdd()) { 841 autoCreateBlock(); 842 AppendStmt(Block, S, asc); 843 } 844 845 return VisitChildren(S); 846} 847 848/// VisitChildren - Visit the children of a Stmt. 849CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 850 CFGBlock *B = Block; 851 for (Stmt::child_iterator I = Terminator->child_begin(), 852 E = Terminator->child_end(); I != E; ++I) { 853 if (*I) B = Visit(*I); 854 } 855 return B; 856} 857 858CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 859 AddStmtChoice asc) { 860 AddressTakenLabels.insert(A->getLabel()); 861 862 if (asc.alwaysAdd()) { 863 autoCreateBlock(); 864 AppendStmt(Block, A, asc); 865 } 866 867 return Block; 868} 869 870CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 871 AddStmtChoice asc) { 872 if (B->isLogicalOp()) { // && or || 873 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 874 AppendStmt(ConfluenceBlock, B, asc); 875 876 if (badCFG) 877 return 0; 878 879 // create the block evaluating the LHS 880 CFGBlock* LHSBlock = createBlock(false); 881 LHSBlock->setTerminator(B); 882 883 // create the block evaluating the RHS 884 Succ = ConfluenceBlock; 885 Block = NULL; 886 CFGBlock* RHSBlock = addStmt(B->getRHS()); 887 888 if (RHSBlock) { 889 if (badCFG) 890 return 0; 891 } 892 else { 893 // Create an empty block for cases where the RHS doesn't require 894 // any explicit statements in the CFG. 895 RHSBlock = createBlock(); 896 } 897 898 // See if this is a known constant. 899 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 900 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 901 KnownVal.negate(); 902 903 // Now link the LHSBlock with RHSBlock. 904 if (B->getOpcode() == BO_LOr) { 905 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 906 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 907 } else { 908 assert(B->getOpcode() == BO_LAnd); 909 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 910 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 911 } 912 913 // Generate the blocks for evaluating the LHS. 914 Block = LHSBlock; 915 return addStmt(B->getLHS()); 916 } 917 else if (B->getOpcode() == BO_Comma) { // , 918 autoCreateBlock(); 919 AppendStmt(Block, B, asc); 920 addStmt(B->getRHS()); 921 return addStmt(B->getLHS()); 922 } 923 else if (B->isAssignmentOp()) { 924 if (asc.alwaysAdd()) { 925 autoCreateBlock(); 926 AppendStmt(Block, B, asc); 927 } 928 929 Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 930 return Visit(B->getRHS()); 931 } 932 933 if (asc.alwaysAdd()) { 934 autoCreateBlock(); 935 AppendStmt(Block, B, asc); 936 } 937 938 CFGBlock *RBlock = Visit(B->getRHS()); 939 CFGBlock *LBlock = Visit(B->getLHS()); 940 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 941 // containing a DoStmt, and the LHS doesn't create a new block, then we should 942 // return RBlock. Otherwise we'll incorrectly return NULL. 943 return (LBlock ? LBlock : RBlock); 944} 945 946CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 947 if (asc.alwaysAdd()) { 948 autoCreateBlock(); 949 AppendStmt(Block, E, asc); 950 } 951 return Block; 952} 953 954CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 955 // "break" is a control-flow statement. Thus we stop processing the current 956 // block. 957 if (badCFG) 958 return 0; 959 960 // Now create a new block that ends with the break statement. 961 Block = createBlock(false); 962 Block->setTerminator(B); 963 964 // If there is no target for the break, then we are looking at an incomplete 965 // AST. This means that the CFG cannot be constructed. 966 if (BreakJumpTarget.Block) { 967 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 968 AddSuccessor(Block, BreakJumpTarget.Block); 969 } else 970 badCFG = true; 971 972 973 return Block; 974} 975 976static bool CanThrow(Expr *E) { 977 QualType Ty = E->getType(); 978 if (Ty->isFunctionPointerType()) 979 Ty = Ty->getAs<PointerType>()->getPointeeType(); 980 else if (Ty->isBlockPointerType()) 981 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 982 983 const FunctionType *FT = Ty->getAs<FunctionType>(); 984 if (FT) { 985 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 986 if (Proto->hasEmptyExceptionSpec()) 987 return false; 988 } 989 return true; 990} 991 992CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 993 // If this is a call to a no-return function, this stops the block here. 994 bool NoReturn = false; 995 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 996 NoReturn = true; 997 } 998 999 bool AddEHEdge = false; 1000 1001 // Languages without exceptions are assumed to not throw. 1002 if (Context->getLangOptions().Exceptions) { 1003 if (BuildOpts.AddEHEdges) 1004 AddEHEdge = true; 1005 } 1006 1007 if (FunctionDecl *FD = C->getDirectCallee()) { 1008 if (FD->hasAttr<NoReturnAttr>()) 1009 NoReturn = true; 1010 if (FD->hasAttr<NoThrowAttr>()) 1011 AddEHEdge = false; 1012 } 1013 1014 if (!CanThrow(C->getCallee())) 1015 AddEHEdge = false; 1016 1017 if (!NoReturn && !AddEHEdge) { 1018 if (asc.asLValue()) 1019 return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue); 1020 else 1021 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 1022 } 1023 1024 if (Block) { 1025 Succ = Block; 1026 if (badCFG) 1027 return 0; 1028 } 1029 1030 Block = createBlock(!NoReturn); 1031 AppendStmt(Block, C, asc); 1032 1033 if (NoReturn) { 1034 // Wire this to the exit block directly. 1035 AddSuccessor(Block, &cfg->getExit()); 1036 } 1037 if (AddEHEdge) { 1038 // Add exceptional edges. 1039 if (TryTerminatedBlock) 1040 AddSuccessor(Block, TryTerminatedBlock); 1041 else 1042 AddSuccessor(Block, &cfg->getExit()); 1043 } 1044 1045 return VisitChildren(C); 1046} 1047 1048CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1049 AddStmtChoice asc) { 1050 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1051 AppendStmt(ConfluenceBlock, C, asc); 1052 if (badCFG) 1053 return 0; 1054 1055 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1056 : AddStmtChoice::AlwaysAdd; 1057 1058 Succ = ConfluenceBlock; 1059 Block = NULL; 1060 CFGBlock* LHSBlock = Visit(C->getLHS(), asc); 1061 if (badCFG) 1062 return 0; 1063 1064 Succ = ConfluenceBlock; 1065 Block = NULL; 1066 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1067 if (badCFG) 1068 return 0; 1069 1070 Block = createBlock(false); 1071 // See if this is a known constant. 1072 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1073 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1074 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1075 Block->setTerminator(C); 1076 return addStmt(C->getCond()); 1077} 1078 1079 1080CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1081 addLocalScopeAndDtors(C); 1082 CFGBlock* LastBlock = Block; 1083 1084 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1085 I != E; ++I ) { 1086 // If we hit a segment of code just containing ';' (NullStmts), we can 1087 // get a null block back. In such cases, just use the LastBlock 1088 if (CFGBlock *newBlock = addStmt(*I)) 1089 LastBlock = newBlock; 1090 1091 if (badCFG) 1092 return NULL; 1093 } 1094 1095 return LastBlock; 1096} 1097 1098CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1099 AddStmtChoice asc) { 1100 // Create the confluence block that will "merge" the results of the ternary 1101 // expression. 1102 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1103 AppendStmt(ConfluenceBlock, C, asc); 1104 if (badCFG) 1105 return 0; 1106 1107 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1108 : AddStmtChoice::AlwaysAdd; 1109 1110 // Create a block for the LHS expression if there is an LHS expression. A 1111 // GCC extension allows LHS to be NULL, causing the condition to be the 1112 // value that is returned instead. 1113 // e.g: x ?: y is shorthand for: x ? x : y; 1114 Succ = ConfluenceBlock; 1115 Block = NULL; 1116 CFGBlock* LHSBlock = NULL; 1117 if (C->getLHS()) { 1118 LHSBlock = Visit(C->getLHS(), asc); 1119 if (badCFG) 1120 return 0; 1121 Block = NULL; 1122 } 1123 1124 // Create the block for the RHS expression. 1125 Succ = ConfluenceBlock; 1126 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1127 if (badCFG) 1128 return 0; 1129 1130 // Create the block that will contain the condition. 1131 Block = createBlock(false); 1132 1133 // See if this is a known constant. 1134 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1135 if (LHSBlock) { 1136 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1137 } else { 1138 if (KnownVal.isFalse()) { 1139 // If we know the condition is false, add NULL as the successor for 1140 // the block containing the condition. In this case, the confluence 1141 // block will have just one predecessor. 1142 AddSuccessor(Block, 0); 1143 assert(ConfluenceBlock->pred_size() == 1); 1144 } else { 1145 // If we have no LHS expression, add the ConfluenceBlock as a direct 1146 // successor for the block containing the condition. Moreover, we need to 1147 // reverse the order of the predecessors in the ConfluenceBlock because 1148 // the RHSBlock will have been added to the succcessors already, and we 1149 // want the first predecessor to the the block containing the expression 1150 // for the case when the ternary expression evaluates to true. 1151 AddSuccessor(Block, ConfluenceBlock); 1152 assert(ConfluenceBlock->pred_size() == 2); 1153 std::reverse(ConfluenceBlock->pred_begin(), 1154 ConfluenceBlock->pred_end()); 1155 } 1156 } 1157 1158 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1159 Block->setTerminator(C); 1160 return addStmt(C->getCond()); 1161} 1162 1163CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1164 autoCreateBlock(); 1165 1166 if (DS->isSingleDecl()) { 1167 AppendStmt(Block, DS); 1168 return VisitDeclSubExpr(DS->getSingleDecl()); 1169 } 1170 1171 CFGBlock *B = 0; 1172 1173 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1174 typedef llvm::SmallVector<Decl*,10> BufTy; 1175 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1176 1177 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1178 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1179 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1180 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1181 1182 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1183 // automatically freed with the CFG. 1184 DeclGroupRef DG(*I); 1185 Decl *D = *I; 1186 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1187 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1188 1189 // Append the fake DeclStmt to block. 1190 AppendStmt(Block, DSNew); 1191 B = VisitDeclSubExpr(D); 1192 } 1193 1194 return B; 1195} 1196 1197/// VisitDeclSubExpr - Utility method to add block-level expressions for 1198/// initializers in Decls. 1199CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 1200 assert(Block); 1201 1202 VarDecl *VD = dyn_cast<VarDecl>(D); 1203 1204 if (!VD) 1205 return Block; 1206 1207 Expr *Init = VD->getInit(); 1208 1209 if (Init) { 1210 AddStmtChoice::Kind k = 1211 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 1212 : AddStmtChoice::NotAlwaysAdd; 1213 Visit(Init, AddStmtChoice(k)); 1214 } 1215 1216 // If the type of VD is a VLA, then we must process its size expressions. 1217 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1218 VA = FindVA(VA->getElementType().getTypePtr())) 1219 Block = addStmt(VA->getSizeExpr()); 1220 1221 // Remove variable from local scope. 1222 if (ScopePos && VD == *ScopePos) 1223 ++ScopePos; 1224 1225 return Block; 1226} 1227 1228CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1229 // We may see an if statement in the middle of a basic block, or it may be the 1230 // first statement we are processing. In either case, we create a new basic 1231 // block. First, we create the blocks for the then...else statements, and 1232 // then we create the block containing the if statement. If we were in the 1233 // middle of a block, we stop processing that block. That block is then the 1234 // implicit successor for the "then" and "else" clauses. 1235 1236 // Save local scope position because in case of condition variable ScopePos 1237 // won't be restored when traversing AST. 1238 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1239 1240 // Create local scope for possible condition variable. 1241 // Store scope position. Add implicit destructor. 1242 if (VarDecl* VD = I->getConditionVariable()) { 1243 LocalScope::const_iterator BeginScopePos = ScopePos; 1244 addLocalScopeForVarDecl(VD); 1245 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1246 } 1247 1248 // The block we were proccessing is now finished. Make it the successor 1249 // block. 1250 if (Block) { 1251 Succ = Block; 1252 if (badCFG) 1253 return 0; 1254 } 1255 1256 // Process the false branch. 1257 CFGBlock* ElseBlock = Succ; 1258 1259 if (Stmt* Else = I->getElse()) { 1260 SaveAndRestore<CFGBlock*> sv(Succ); 1261 1262 // NULL out Block so that the recursive call to Visit will 1263 // create a new basic block. 1264 Block = NULL; 1265 1266 // If branch is not a compound statement create implicit scope 1267 // and add destructors. 1268 if (!isa<CompoundStmt>(Else)) 1269 addLocalScopeAndDtors(Else); 1270 1271 ElseBlock = addStmt(Else); 1272 1273 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1274 ElseBlock = sv.get(); 1275 else if (Block) { 1276 if (badCFG) 1277 return 0; 1278 } 1279 } 1280 1281 // Process the true branch. 1282 CFGBlock* ThenBlock; 1283 { 1284 Stmt* Then = I->getThen(); 1285 assert(Then); 1286 SaveAndRestore<CFGBlock*> sv(Succ); 1287 Block = NULL; 1288 1289 // If branch is not a compound statement create implicit scope 1290 // and add destructors. 1291 if (!isa<CompoundStmt>(Then)) 1292 addLocalScopeAndDtors(Then); 1293 1294 ThenBlock = addStmt(Then); 1295 1296 if (!ThenBlock) { 1297 // We can reach here if the "then" body has all NullStmts. 1298 // Create an empty block so we can distinguish between true and false 1299 // branches in path-sensitive analyses. 1300 ThenBlock = createBlock(false); 1301 AddSuccessor(ThenBlock, sv.get()); 1302 } else if (Block) { 1303 if (badCFG) 1304 return 0; 1305 } 1306 } 1307 1308 // Now create a new block containing the if statement. 1309 Block = createBlock(false); 1310 1311 // Set the terminator of the new block to the If statement. 1312 Block->setTerminator(I); 1313 1314 // See if this is a known constant. 1315 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1316 1317 // Now add the successors. 1318 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1319 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1320 1321 // Add the condition as the last statement in the new block. This may create 1322 // new blocks as the condition may contain control-flow. Any newly created 1323 // blocks will be pointed to be "Block". 1324 Block = addStmt(I->getCond()); 1325 1326 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1327 // and the condition variable initialization to the CFG. 1328 if (VarDecl *VD = I->getConditionVariable()) { 1329 if (Expr *Init = VD->getInit()) { 1330 autoCreateBlock(); 1331 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1332 addStmt(Init); 1333 } 1334 } 1335 1336 return Block; 1337} 1338 1339 1340CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1341 // If we were in the middle of a block we stop processing that block. 1342 // 1343 // NOTE: If a "return" appears in the middle of a block, this means that the 1344 // code afterwards is DEAD (unreachable). We still keep a basic block 1345 // for that code; a simple "mark-and-sweep" from the entry block will be 1346 // able to report such dead blocks. 1347 1348 // Create the new block. 1349 Block = createBlock(false); 1350 1351 // The Exit block is the only successor. 1352 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1353 AddSuccessor(Block, &cfg->getExit()); 1354 1355 // Add the return statement to the block. This may create new blocks if R 1356 // contains control-flow (short-circuit operations). 1357 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1358} 1359 1360CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1361 // Get the block of the labeled statement. Add it to our map. 1362 addStmt(L->getSubStmt()); 1363 CFGBlock* LabelBlock = Block; 1364 1365 if (!LabelBlock) // This can happen when the body is empty, i.e. 1366 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1367 1368 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1369 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1370 1371 // Labels partition blocks, so this is the end of the basic block we were 1372 // processing (L is the block's label). Because this is label (and we have 1373 // already processed the substatement) there is no extra control-flow to worry 1374 // about. 1375 LabelBlock->setLabel(L); 1376 if (badCFG) 1377 return 0; 1378 1379 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1380 Block = NULL; 1381 1382 // This block is now the implicit successor of other blocks. 1383 Succ = LabelBlock; 1384 1385 return LabelBlock; 1386} 1387 1388CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1389 // Goto is a control-flow statement. Thus we stop processing the current 1390 // block and create a new one. 1391 1392 Block = createBlock(false); 1393 Block->setTerminator(G); 1394 1395 // If we already know the mapping to the label block add the successor now. 1396 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1397 1398 if (I == LabelMap.end()) 1399 // We will need to backpatch this block later. 1400 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1401 else { 1402 JumpTarget JT = I->second; 1403 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1404 AddSuccessor(Block, JT.Block); 1405 } 1406 1407 return Block; 1408} 1409 1410CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1411 CFGBlock* LoopSuccessor = NULL; 1412 1413 // Save local scope position because in case of condition variable ScopePos 1414 // won't be restored when traversing AST. 1415 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1416 1417 // Create local scope for init statement and possible condition variable. 1418 // Add destructor for init statement and condition variable. 1419 // Store scope position for continue statement. 1420 if (Stmt* Init = F->getInit()) 1421 addLocalScopeForStmt(Init); 1422 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1423 1424 if (VarDecl* VD = F->getConditionVariable()) 1425 addLocalScopeForVarDecl(VD); 1426 LocalScope::const_iterator ContinueScopePos = ScopePos; 1427 1428 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1429 1430 // "for" is a control-flow statement. Thus we stop processing the current 1431 // block. 1432 if (Block) { 1433 if (badCFG) 1434 return 0; 1435 LoopSuccessor = Block; 1436 } else 1437 LoopSuccessor = Succ; 1438 1439 // Save the current value for the break targets. 1440 // All breaks should go to the code following the loop. 1441 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1442 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1443 1444 // Because of short-circuit evaluation, the condition of the loop can span 1445 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1446 // evaluate the condition. 1447 CFGBlock* ExitConditionBlock = createBlock(false); 1448 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1449 1450 // Set the terminator for the "exit" condition block. 1451 ExitConditionBlock->setTerminator(F); 1452 1453 // Now add the actual condition to the condition block. Because the condition 1454 // itself may contain control-flow, new blocks may be created. 1455 if (Stmt* C = F->getCond()) { 1456 Block = ExitConditionBlock; 1457 EntryConditionBlock = addStmt(C); 1458 assert(Block == EntryConditionBlock || 1459 (Block == 0 && EntryConditionBlock == Succ)); 1460 1461 // If this block contains a condition variable, add both the condition 1462 // variable and initializer to the CFG. 1463 if (VarDecl *VD = F->getConditionVariable()) { 1464 if (Expr *Init = VD->getInit()) { 1465 autoCreateBlock(); 1466 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1467 EntryConditionBlock = addStmt(Init); 1468 assert(Block == EntryConditionBlock); 1469 } 1470 } 1471 1472 if (Block) { 1473 if (badCFG) 1474 return 0; 1475 } 1476 } 1477 1478 // The condition block is the implicit successor for the loop body as well as 1479 // any code above the loop. 1480 Succ = EntryConditionBlock; 1481 1482 // See if this is a known constant. 1483 TryResult KnownVal(true); 1484 1485 if (F->getCond()) 1486 KnownVal = TryEvaluateBool(F->getCond()); 1487 1488 // Now create the loop body. 1489 { 1490 assert(F->getBody()); 1491 1492 // Save the current values for Block, Succ, and continue targets. 1493 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1494 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1495 1496 // Create a new block to contain the (bottom) of the loop body. 1497 Block = NULL; 1498 1499 // Loop body should end with destructor of Condition variable (if any). 1500 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1501 1502 if (Stmt* I = F->getInc()) { 1503 // Generate increment code in its own basic block. This is the target of 1504 // continue statements. 1505 Succ = addStmt(I); 1506 } else { 1507 // No increment code. Create a special, empty, block that is used as the 1508 // target block for "looping back" to the start of the loop. 1509 assert(Succ == EntryConditionBlock); 1510 Succ = Block ? Block : createBlock(); 1511 } 1512 1513 // Finish up the increment (or empty) block if it hasn't been already. 1514 if (Block) { 1515 assert(Block == Succ); 1516 if (badCFG) 1517 return 0; 1518 Block = 0; 1519 } 1520 1521 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1522 1523 // The starting block for the loop increment is the block that should 1524 // represent the 'loop target' for looping back to the start of the loop. 1525 ContinueJumpTarget.Block->setLoopTarget(F); 1526 1527 // If body is not a compound statement create implicit scope 1528 // and add destructors. 1529 if (!isa<CompoundStmt>(F->getBody())) 1530 addLocalScopeAndDtors(F->getBody()); 1531 1532 // Now populate the body block, and in the process create new blocks as we 1533 // walk the body of the loop. 1534 CFGBlock* BodyBlock = addStmt(F->getBody()); 1535 1536 if (!BodyBlock) 1537 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1538 else if (badCFG) 1539 return 0; 1540 1541 // This new body block is a successor to our "exit" condition block. 1542 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1543 } 1544 1545 // Link up the condition block with the code that follows the loop. (the 1546 // false branch). 1547 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1548 1549 // If the loop contains initialization, create a new block for those 1550 // statements. This block can also contain statements that precede the loop. 1551 if (Stmt* I = F->getInit()) { 1552 Block = createBlock(); 1553 return addStmt(I); 1554 } else { 1555 // There is no loop initialization. We are thus basically a while loop. 1556 // NULL out Block to force lazy block construction. 1557 Block = NULL; 1558 Succ = EntryConditionBlock; 1559 return EntryConditionBlock; 1560 } 1561} 1562 1563CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1564 if (asc.alwaysAdd()) { 1565 autoCreateBlock(); 1566 AppendStmt(Block, M, asc); 1567 } 1568 return Visit(M->getBase(), 1569 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1570 : AddStmtChoice::AsLValueNotAlwaysAdd); 1571} 1572 1573CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1574 // Objective-C fast enumeration 'for' statements: 1575 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1576 // 1577 // for ( Type newVariable in collection_expression ) { statements } 1578 // 1579 // becomes: 1580 // 1581 // prologue: 1582 // 1. collection_expression 1583 // T. jump to loop_entry 1584 // loop_entry: 1585 // 1. side-effects of element expression 1586 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1587 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1588 // TB: 1589 // statements 1590 // T. jump to loop_entry 1591 // FB: 1592 // what comes after 1593 // 1594 // and 1595 // 1596 // Type existingItem; 1597 // for ( existingItem in expression ) { statements } 1598 // 1599 // becomes: 1600 // 1601 // the same with newVariable replaced with existingItem; the binding works 1602 // the same except that for one ObjCForCollectionStmt::getElement() returns 1603 // a DeclStmt and the other returns a DeclRefExpr. 1604 // 1605 1606 CFGBlock* LoopSuccessor = 0; 1607 1608 if (Block) { 1609 if (badCFG) 1610 return 0; 1611 LoopSuccessor = Block; 1612 Block = 0; 1613 } else 1614 LoopSuccessor = Succ; 1615 1616 // Build the condition blocks. 1617 CFGBlock* ExitConditionBlock = createBlock(false); 1618 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1619 1620 // Set the terminator for the "exit" condition block. 1621 ExitConditionBlock->setTerminator(S); 1622 1623 // The last statement in the block should be the ObjCForCollectionStmt, which 1624 // performs the actual binding to 'element' and determines if there are any 1625 // more items in the collection. 1626 AppendStmt(ExitConditionBlock, S); 1627 Block = ExitConditionBlock; 1628 1629 // Walk the 'element' expression to see if there are any side-effects. We 1630 // generate new blocks as necesary. We DON'T add the statement by default to 1631 // the CFG unless it contains control-flow. 1632 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1633 if (Block) { 1634 if (badCFG) 1635 return 0; 1636 Block = 0; 1637 } 1638 1639 // The condition block is the implicit successor for the loop body as well as 1640 // any code above the loop. 1641 Succ = EntryConditionBlock; 1642 1643 // Now create the true branch. 1644 { 1645 // Save the current values for Succ, continue and break targets. 1646 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1647 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1648 save_break(BreakJumpTarget); 1649 1650 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1651 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1652 1653 CFGBlock* BodyBlock = addStmt(S->getBody()); 1654 1655 if (!BodyBlock) 1656 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1657 else if (Block) { 1658 if (badCFG) 1659 return 0; 1660 } 1661 1662 // This new body block is a successor to our "exit" condition block. 1663 AddSuccessor(ExitConditionBlock, BodyBlock); 1664 } 1665 1666 // Link up the condition block with the code that follows the loop. 1667 // (the false branch). 1668 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1669 1670 // Now create a prologue block to contain the collection expression. 1671 Block = createBlock(); 1672 return addStmt(S->getCollection()); 1673} 1674 1675CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1676 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1677 1678 // Inline the body. 1679 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1680 1681 // The sync body starts its own basic block. This makes it a little easier 1682 // for diagnostic clients. 1683 if (SyncBlock) { 1684 if (badCFG) 1685 return 0; 1686 1687 Block = 0; 1688 Succ = SyncBlock; 1689 } 1690 1691 // Add the @synchronized to the CFG. 1692 autoCreateBlock(); 1693 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1694 1695 // Inline the sync expression. 1696 return addStmt(S->getSynchExpr()); 1697} 1698 1699CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1700 // FIXME 1701 return NYS(); 1702} 1703 1704CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1705 CFGBlock* LoopSuccessor = NULL; 1706 1707 // Save local scope position because in case of condition variable ScopePos 1708 // won't be restored when traversing AST. 1709 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1710 1711 // Create local scope for possible condition variable. 1712 // Store scope position for continue statement. 1713 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1714 if (VarDecl* VD = W->getConditionVariable()) { 1715 addLocalScopeForVarDecl(VD); 1716 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1717 } 1718 1719 // "while" is a control-flow statement. Thus we stop processing the current 1720 // block. 1721 if (Block) { 1722 if (badCFG) 1723 return 0; 1724 LoopSuccessor = Block; 1725 } else 1726 LoopSuccessor = Succ; 1727 1728 // Because of short-circuit evaluation, the condition of the loop can span 1729 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1730 // evaluate the condition. 1731 CFGBlock* ExitConditionBlock = createBlock(false); 1732 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1733 1734 // Set the terminator for the "exit" condition block. 1735 ExitConditionBlock->setTerminator(W); 1736 1737 // Now add the actual condition to the condition block. Because the condition 1738 // itself may contain control-flow, new blocks may be created. Thus we update 1739 // "Succ" after adding the condition. 1740 if (Stmt* C = W->getCond()) { 1741 Block = ExitConditionBlock; 1742 EntryConditionBlock = addStmt(C); 1743 // The condition might finish the current 'Block'. 1744 Block = EntryConditionBlock; 1745 1746 // If this block contains a condition variable, add both the condition 1747 // variable and initializer to the CFG. 1748 if (VarDecl *VD = W->getConditionVariable()) { 1749 if (Expr *Init = VD->getInit()) { 1750 autoCreateBlock(); 1751 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1752 EntryConditionBlock = addStmt(Init); 1753 assert(Block == EntryConditionBlock); 1754 } 1755 } 1756 1757 if (Block) { 1758 if (badCFG) 1759 return 0; 1760 } 1761 } 1762 1763 // The condition block is the implicit successor for the loop body as well as 1764 // any code above the loop. 1765 Succ = EntryConditionBlock; 1766 1767 // See if this is a known constant. 1768 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1769 1770 // Process the loop body. 1771 { 1772 assert(W->getBody()); 1773 1774 // Save the current values for Block, Succ, and continue and break targets 1775 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1776 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1777 save_break(BreakJumpTarget); 1778 1779 // Create an empty block to represent the transition block for looping back 1780 // to the head of the loop. 1781 Block = 0; 1782 assert(Succ == EntryConditionBlock); 1783 Succ = createBlock(); 1784 Succ->setLoopTarget(W); 1785 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1786 1787 // All breaks should go to the code following the loop. 1788 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1789 1790 // NULL out Block to force lazy instantiation of blocks for the body. 1791 Block = NULL; 1792 1793 // Loop body should end with destructor of Condition variable (if any). 1794 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1795 1796 // If body is not a compound statement create implicit scope 1797 // and add destructors. 1798 if (!isa<CompoundStmt>(W->getBody())) 1799 addLocalScopeAndDtors(W->getBody()); 1800 1801 // Create the body. The returned block is the entry to the loop body. 1802 CFGBlock* BodyBlock = addStmt(W->getBody()); 1803 1804 if (!BodyBlock) 1805 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1806 else if (Block) { 1807 if (badCFG) 1808 return 0; 1809 } 1810 1811 // Add the loop body entry as a successor to the condition. 1812 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1813 } 1814 1815 // Link up the condition block with the code that follows the loop. (the 1816 // false branch). 1817 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1818 1819 // There can be no more statements in the condition block since we loop back 1820 // to this block. NULL out Block to force lazy creation of another block. 1821 Block = NULL; 1822 1823 // Return the condition block, which is the dominating block for the loop. 1824 Succ = EntryConditionBlock; 1825 return EntryConditionBlock; 1826} 1827 1828 1829CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1830 // FIXME: For now we pretend that @catch and the code it contains does not 1831 // exit. 1832 return Block; 1833} 1834 1835CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1836 // FIXME: This isn't complete. We basically treat @throw like a return 1837 // statement. 1838 1839 // If we were in the middle of a block we stop processing that block. 1840 if (badCFG) 1841 return 0; 1842 1843 // Create the new block. 1844 Block = createBlock(false); 1845 1846 // The Exit block is the only successor. 1847 AddSuccessor(Block, &cfg->getExit()); 1848 1849 // Add the statement to the block. This may create new blocks if S contains 1850 // control-flow (short-circuit operations). 1851 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1852} 1853 1854CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1855 // If we were in the middle of a block we stop processing that block. 1856 if (badCFG) 1857 return 0; 1858 1859 // Create the new block. 1860 Block = createBlock(false); 1861 1862 if (TryTerminatedBlock) 1863 // The current try statement is the only successor. 1864 AddSuccessor(Block, TryTerminatedBlock); 1865 else 1866 // otherwise the Exit block is the only successor. 1867 AddSuccessor(Block, &cfg->getExit()); 1868 1869 // Add the statement to the block. This may create new blocks if S contains 1870 // control-flow (short-circuit operations). 1871 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1872} 1873 1874CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1875 CFGBlock* LoopSuccessor = NULL; 1876 1877 // "do...while" is a control-flow statement. Thus we stop processing the 1878 // current block. 1879 if (Block) { 1880 if (badCFG) 1881 return 0; 1882 LoopSuccessor = Block; 1883 } else 1884 LoopSuccessor = Succ; 1885 1886 // Because of short-circuit evaluation, the condition of the loop can span 1887 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1888 // evaluate the condition. 1889 CFGBlock* ExitConditionBlock = createBlock(false); 1890 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1891 1892 // Set the terminator for the "exit" condition block. 1893 ExitConditionBlock->setTerminator(D); 1894 1895 // Now add the actual condition to the condition block. Because the condition 1896 // itself may contain control-flow, new blocks may be created. 1897 if (Stmt* C = D->getCond()) { 1898 Block = ExitConditionBlock; 1899 EntryConditionBlock = addStmt(C); 1900 if (Block) { 1901 if (badCFG) 1902 return 0; 1903 } 1904 } 1905 1906 // The condition block is the implicit successor for the loop body. 1907 Succ = EntryConditionBlock; 1908 1909 // See if this is a known constant. 1910 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1911 1912 // Process the loop body. 1913 CFGBlock* BodyBlock = NULL; 1914 { 1915 assert(D->getBody()); 1916 1917 // Save the current values for Block, Succ, and continue and break targets 1918 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1919 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1920 save_break(BreakJumpTarget); 1921 1922 // All continues within this loop should go to the condition block 1923 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1924 1925 // All breaks should go to the code following the loop. 1926 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1927 1928 // NULL out Block to force lazy instantiation of blocks for the body. 1929 Block = NULL; 1930 1931 // If body is not a compound statement create implicit scope 1932 // and add destructors. 1933 if (!isa<CompoundStmt>(D->getBody())) 1934 addLocalScopeAndDtors(D->getBody()); 1935 1936 // Create the body. The returned block is the entry to the loop body. 1937 BodyBlock = addStmt(D->getBody()); 1938 1939 if (!BodyBlock) 1940 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1941 else if (Block) { 1942 if (badCFG) 1943 return 0; 1944 } 1945 1946 if (!KnownVal.isFalse()) { 1947 // Add an intermediate block between the BodyBlock and the 1948 // ExitConditionBlock to represent the "loop back" transition. Create an 1949 // empty block to represent the transition block for looping back to the 1950 // head of the loop. 1951 // FIXME: Can we do this more efficiently without adding another block? 1952 Block = NULL; 1953 Succ = BodyBlock; 1954 CFGBlock *LoopBackBlock = createBlock(); 1955 LoopBackBlock->setLoopTarget(D); 1956 1957 // Add the loop body entry as a successor to the condition. 1958 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1959 } 1960 else 1961 AddSuccessor(ExitConditionBlock, NULL); 1962 } 1963 1964 // Link up the condition block with the code that follows the loop. 1965 // (the false branch). 1966 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1967 1968 // There can be no more statements in the body block(s) since we loop back to 1969 // the body. NULL out Block to force lazy creation of another block. 1970 Block = NULL; 1971 1972 // Return the loop body, which is the dominating block for the loop. 1973 Succ = BodyBlock; 1974 return BodyBlock; 1975} 1976 1977CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1978 // "continue" is a control-flow statement. Thus we stop processing the 1979 // current block. 1980 if (badCFG) 1981 return 0; 1982 1983 // Now create a new block that ends with the continue statement. 1984 Block = createBlock(false); 1985 Block->setTerminator(C); 1986 1987 // If there is no target for the continue, then we are looking at an 1988 // incomplete AST. This means the CFG cannot be constructed. 1989 if (ContinueJumpTarget.Block) { 1990 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1991 AddSuccessor(Block, ContinueJumpTarget.Block); 1992 } else 1993 badCFG = true; 1994 1995 return Block; 1996} 1997 1998CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1999 AddStmtChoice asc) { 2000 2001 if (asc.alwaysAdd()) { 2002 autoCreateBlock(); 2003 AppendStmt(Block, E); 2004 } 2005 2006 // VLA types have expressions that must be evaluated. 2007 if (E->isArgumentType()) { 2008 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 2009 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2010 addStmt(VA->getSizeExpr()); 2011 } 2012 2013 return Block; 2014} 2015 2016/// VisitStmtExpr - Utility method to handle (nested) statement 2017/// expressions (a GCC extension). 2018CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2019 if (asc.alwaysAdd()) { 2020 autoCreateBlock(); 2021 AppendStmt(Block, SE); 2022 } 2023 return VisitCompoundStmt(SE->getSubStmt()); 2024} 2025 2026CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2027 // "switch" is a control-flow statement. Thus we stop processing the current 2028 // block. 2029 CFGBlock* SwitchSuccessor = NULL; 2030 2031 // Save local scope position because in case of condition variable ScopePos 2032 // won't be restored when traversing AST. 2033 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2034 2035 // Create local scope for possible condition variable. 2036 // Store scope position. Add implicit destructor. 2037 if (VarDecl* VD = Terminator->getConditionVariable()) { 2038 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2039 addLocalScopeForVarDecl(VD); 2040 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2041 } 2042 2043 if (Block) { 2044 if (badCFG) 2045 return 0; 2046 SwitchSuccessor = Block; 2047 } else SwitchSuccessor = Succ; 2048 2049 // Save the current "switch" context. 2050 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2051 save_default(DefaultCaseBlock); 2052 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2053 2054 // Set the "default" case to be the block after the switch statement. If the 2055 // switch statement contains a "default:", this value will be overwritten with 2056 // the block for that code. 2057 DefaultCaseBlock = SwitchSuccessor; 2058 2059 // Create a new block that will contain the switch statement. 2060 SwitchTerminatedBlock = createBlock(false); 2061 2062 // Now process the switch body. The code after the switch is the implicit 2063 // successor. 2064 Succ = SwitchSuccessor; 2065 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2066 2067 // When visiting the body, the case statements should automatically get linked 2068 // up to the switch. We also don't keep a pointer to the body, since all 2069 // control-flow from the switch goes to case/default statements. 2070 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2071 Block = NULL; 2072 2073 // If body is not a compound statement create implicit scope 2074 // and add destructors. 2075 if (!isa<CompoundStmt>(Terminator->getBody())) 2076 addLocalScopeAndDtors(Terminator->getBody()); 2077 2078 addStmt(Terminator->getBody()); 2079 if (Block) { 2080 if (badCFG) 2081 return 0; 2082 } 2083 2084 // If we have no "default:" case, the default transition is to the code 2085 // following the switch body. 2086 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2087 2088 // Add the terminator and condition in the switch block. 2089 SwitchTerminatedBlock->setTerminator(Terminator); 2090 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2091 Block = SwitchTerminatedBlock; 2092 Block = addStmt(Terminator->getCond()); 2093 2094 // Finally, if the SwitchStmt contains a condition variable, add both the 2095 // SwitchStmt and the condition variable initialization to the CFG. 2096 if (VarDecl *VD = Terminator->getConditionVariable()) { 2097 if (Expr *Init = VD->getInit()) { 2098 autoCreateBlock(); 2099 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2100 addStmt(Init); 2101 } 2102 } 2103 2104 return Block; 2105} 2106 2107CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2108 // CaseStmts are essentially labels, so they are the first statement in a 2109 // block. 2110 CFGBlock *TopBlock = 0, *LastBlock = 0; 2111 2112 if (Stmt *Sub = CS->getSubStmt()) { 2113 // For deeply nested chains of CaseStmts, instead of doing a recursion 2114 // (which can blow out the stack), manually unroll and create blocks 2115 // along the way. 2116 while (isa<CaseStmt>(Sub)) { 2117 CFGBlock *CurrentBlock = createBlock(false); 2118 CurrentBlock->setLabel(CS); 2119 2120 if (TopBlock) 2121 AddSuccessor(LastBlock, CurrentBlock); 2122 else 2123 TopBlock = CurrentBlock; 2124 2125 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2126 LastBlock = CurrentBlock; 2127 2128 CS = cast<CaseStmt>(Sub); 2129 Sub = CS->getSubStmt(); 2130 } 2131 2132 addStmt(Sub); 2133 } 2134 2135 CFGBlock* CaseBlock = Block; 2136 if (!CaseBlock) 2137 CaseBlock = createBlock(); 2138 2139 // Cases statements partition blocks, so this is the top of the basic block we 2140 // were processing (the "case XXX:" is the label). 2141 CaseBlock->setLabel(CS); 2142 2143 if (badCFG) 2144 return 0; 2145 2146 // Add this block to the list of successors for the block with the switch 2147 // statement. 2148 assert(SwitchTerminatedBlock); 2149 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2150 2151 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2152 Block = NULL; 2153 2154 if (TopBlock) { 2155 AddSuccessor(LastBlock, CaseBlock); 2156 Succ = TopBlock; 2157 } 2158 else { 2159 // This block is now the implicit successor of other blocks. 2160 Succ = CaseBlock; 2161 } 2162 2163 return Succ; 2164} 2165 2166CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2167 if (Terminator->getSubStmt()) 2168 addStmt(Terminator->getSubStmt()); 2169 2170 DefaultCaseBlock = Block; 2171 2172 if (!DefaultCaseBlock) 2173 DefaultCaseBlock = createBlock(); 2174 2175 // Default statements partition blocks, so this is the top of the basic block 2176 // we were processing (the "default:" is the label). 2177 DefaultCaseBlock->setLabel(Terminator); 2178 2179 if (badCFG) 2180 return 0; 2181 2182 // Unlike case statements, we don't add the default block to the successors 2183 // for the switch statement immediately. This is done when we finish 2184 // processing the switch statement. This allows for the default case 2185 // (including a fall-through to the code after the switch statement) to always 2186 // be the last successor of a switch-terminated block. 2187 2188 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2189 Block = NULL; 2190 2191 // This block is now the implicit successor of other blocks. 2192 Succ = DefaultCaseBlock; 2193 2194 return DefaultCaseBlock; 2195} 2196 2197CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2198 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2199 // current block. 2200 CFGBlock* TrySuccessor = NULL; 2201 2202 if (Block) { 2203 if (badCFG) 2204 return 0; 2205 TrySuccessor = Block; 2206 } else TrySuccessor = Succ; 2207 2208 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2209 2210 // Create a new block that will contain the try statement. 2211 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2212 // Add the terminator in the try block. 2213 NewTryTerminatedBlock->setTerminator(Terminator); 2214 2215 bool HasCatchAll = false; 2216 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2217 // The code after the try is the implicit successor. 2218 Succ = TrySuccessor; 2219 CXXCatchStmt *CS = Terminator->getHandler(h); 2220 if (CS->getExceptionDecl() == 0) { 2221 HasCatchAll = true; 2222 } 2223 Block = NULL; 2224 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2225 if (CatchBlock == 0) 2226 return 0; 2227 // Add this block to the list of successors for the block with the try 2228 // statement. 2229 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2230 } 2231 if (!HasCatchAll) { 2232 if (PrevTryTerminatedBlock) 2233 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2234 else 2235 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2236 } 2237 2238 // The code after the try is the implicit successor. 2239 Succ = TrySuccessor; 2240 2241 // Save the current "try" context. 2242 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2243 TryTerminatedBlock = NewTryTerminatedBlock; 2244 2245 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2246 Block = NULL; 2247 Block = addStmt(Terminator->getTryBlock()); 2248 return Block; 2249} 2250 2251CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2252 // CXXCatchStmt are treated like labels, so they are the first statement in a 2253 // block. 2254 2255 // Save local scope position because in case of exception variable ScopePos 2256 // won't be restored when traversing AST. 2257 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2258 2259 // Create local scope for possible exception variable. 2260 // Store scope position. Add implicit destructor. 2261 if (VarDecl* VD = CS->getExceptionDecl()) { 2262 LocalScope::const_iterator BeginScopePos = ScopePos; 2263 addLocalScopeForVarDecl(VD); 2264 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2265 } 2266 2267 if (CS->getHandlerBlock()) 2268 addStmt(CS->getHandlerBlock()); 2269 2270 CFGBlock* CatchBlock = Block; 2271 if (!CatchBlock) 2272 CatchBlock = createBlock(); 2273 2274 CatchBlock->setLabel(CS); 2275 2276 if (badCFG) 2277 return 0; 2278 2279 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2280 Block = NULL; 2281 2282 return CatchBlock; 2283} 2284 2285CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2286 AddStmtChoice asc) { 2287 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2288 : AddStmtChoice::AlwaysAdd; 2289 autoCreateBlock(); 2290 AppendStmt(Block, C, AddStmtChoice(K)); 2291 return VisitChildren(C); 2292} 2293 2294CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2295 // Lazily create the indirect-goto dispatch block if there isn't one already. 2296 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2297 2298 if (!IBlock) { 2299 IBlock = createBlock(false); 2300 cfg->setIndirectGotoBlock(IBlock); 2301 } 2302 2303 // IndirectGoto is a control-flow statement. Thus we stop processing the 2304 // current block and create a new one. 2305 if (badCFG) 2306 return 0; 2307 2308 Block = createBlock(false); 2309 Block->setTerminator(I); 2310 AddSuccessor(Block, IBlock); 2311 return addStmt(I->getTarget()); 2312} 2313 2314} // end anonymous namespace 2315 2316/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2317/// no successors or predecessors. If this is the first block created in the 2318/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2319CFGBlock* CFG::createBlock() { 2320 bool first_block = begin() == end(); 2321 2322 // Create the block. 2323 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2324 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2325 Blocks.push_back(Mem, BlkBVC); 2326 2327 // If this is the first block, set it as the Entry and Exit. 2328 if (first_block) 2329 Entry = Exit = &back(); 2330 2331 // Return the block. 2332 return &back(); 2333} 2334 2335/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2336/// CFG is returned to the caller. 2337CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2338 BuildOptions BO) { 2339 CFGBuilder Builder; 2340 return Builder.buildCFG(D, Statement, C, BO); 2341} 2342 2343//===----------------------------------------------------------------------===// 2344// CFG: Queries for BlkExprs. 2345//===----------------------------------------------------------------------===// 2346 2347namespace { 2348 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2349} 2350 2351static void FindSubExprAssignments(Stmt *S, 2352 llvm::SmallPtrSet<Expr*,50>& Set) { 2353 if (!S) 2354 return; 2355 2356 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2357 Stmt *child = *I; 2358 if (!child) 2359 continue; 2360 2361 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2362 if (B->isAssignmentOp()) Set.insert(B); 2363 2364 FindSubExprAssignments(child, Set); 2365 } 2366} 2367 2368static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2369 BlkExprMapTy* M = new BlkExprMapTy(); 2370 2371 // Look for assignments that are used as subexpressions. These are the only 2372 // assignments that we want to *possibly* register as a block-level 2373 // expression. Basically, if an assignment occurs both in a subexpression and 2374 // at the block-level, it is a block-level expression. 2375 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2376 2377 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2378 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2379 if (CFGStmt S = BI->getAs<CFGStmt>()) 2380 FindSubExprAssignments(S, SubExprAssignments); 2381 2382 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2383 2384 // Iterate over the statements again on identify the Expr* and Stmt* at the 2385 // block-level that are block-level expressions. 2386 2387 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2388 CFGStmt CS = BI->getAs<CFGStmt>(); 2389 if (!CS.isValid()) 2390 continue; 2391 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2392 2393 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2394 // Assignment expressions that are not nested within another 2395 // expression are really "statements" whose value is never used by 2396 // another expression. 2397 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2398 continue; 2399 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2400 // Special handling for statement expressions. The last statement in 2401 // the statement expression is also a block-level expr. 2402 const CompoundStmt* C = Terminator->getSubStmt(); 2403 if (!C->body_empty()) { 2404 unsigned x = M->size(); 2405 (*M)[C->body_back()] = x; 2406 } 2407 } 2408 2409 unsigned x = M->size(); 2410 (*M)[Exp] = x; 2411 } 2412 } 2413 2414 // Look at terminators. The condition is a block-level expression. 2415 2416 Stmt* S = (*I)->getTerminatorCondition(); 2417 2418 if (S && M->find(S) == M->end()) { 2419 unsigned x = M->size(); 2420 (*M)[S] = x; 2421 } 2422 } 2423 2424 return M; 2425} 2426 2427CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2428 assert(S != NULL); 2429 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2430 2431 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2432 BlkExprMapTy::iterator I = M->find(S); 2433 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2434} 2435 2436unsigned CFG::getNumBlkExprs() { 2437 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2438 return M->size(); 2439 else { 2440 // We assume callers interested in the number of BlkExprs will want 2441 // the map constructed if it doesn't already exist. 2442 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2443 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2444 } 2445} 2446 2447//===----------------------------------------------------------------------===// 2448// Filtered walking of the CFG. 2449//===----------------------------------------------------------------------===// 2450 2451bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2452 const CFGBlock *From, const CFGBlock *To) { 2453 2454 if (F.IgnoreDefaultsWithCoveredEnums) { 2455 // If the 'To' has no label or is labeled but the label isn't a 2456 // CaseStmt then filter this edge. 2457 if (const SwitchStmt *S = 2458 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2459 if (S->isAllEnumCasesCovered()) { 2460 const Stmt *L = To->getLabel(); 2461 if (!L || !isa<CaseStmt>(L)) 2462 return true; 2463 } 2464 } 2465 } 2466 2467 return false; 2468} 2469 2470//===----------------------------------------------------------------------===// 2471// Cleanup: CFG dstor. 2472//===----------------------------------------------------------------------===// 2473 2474CFG::~CFG() { 2475 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2476} 2477 2478//===----------------------------------------------------------------------===// 2479// CFG pretty printing 2480//===----------------------------------------------------------------------===// 2481 2482namespace { 2483 2484class StmtPrinterHelper : public PrinterHelper { 2485 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2486 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2487 StmtMapTy StmtMap; 2488 DeclMapTy DeclMap; 2489 signed CurrentBlock; 2490 unsigned CurrentStmt; 2491 const LangOptions &LangOpts; 2492public: 2493 2494 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2495 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2496 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2497 unsigned j = 1; 2498 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2499 BI != BEnd; ++BI, ++j ) { 2500 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2501 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2502 StmtMap[SE] = P; 2503 2504 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2505 DeclMap[DS->getSingleDecl()] = P; 2506 2507 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2508 if (VarDecl* VD = IS->getConditionVariable()) 2509 DeclMap[VD] = P; 2510 2511 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2512 if (VarDecl* VD = FS->getConditionVariable()) 2513 DeclMap[VD] = P; 2514 2515 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2516 if (VarDecl* VD = WS->getConditionVariable()) 2517 DeclMap[VD] = P; 2518 2519 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2520 if (VarDecl* VD = SS->getConditionVariable()) 2521 DeclMap[VD] = P; 2522 2523 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2524 if (VarDecl* VD = CS->getExceptionDecl()) 2525 DeclMap[VD] = P; 2526 } 2527 } 2528 } 2529 } 2530 } 2531 2532 virtual ~StmtPrinterHelper() {} 2533 2534 const LangOptions &getLangOpts() const { return LangOpts; } 2535 void setBlockID(signed i) { CurrentBlock = i; } 2536 void setStmtID(unsigned i) { CurrentStmt = i; } 2537 2538 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2539 StmtMapTy::iterator I = StmtMap.find(S); 2540 2541 if (I == StmtMap.end()) 2542 return false; 2543 2544 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2545 && I->second.second == CurrentStmt) { 2546 return false; 2547 } 2548 2549 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2550 return true; 2551 } 2552 2553 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2554 DeclMapTy::iterator I = DeclMap.find(D); 2555 2556 if (I == DeclMap.end()) 2557 return false; 2558 2559 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2560 && I->second.second == CurrentStmt) { 2561 return false; 2562 } 2563 2564 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2565 return true; 2566 } 2567}; 2568} // end anonymous namespace 2569 2570 2571namespace { 2572class CFGBlockTerminatorPrint 2573 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2574 2575 llvm::raw_ostream& OS; 2576 StmtPrinterHelper* Helper; 2577 PrintingPolicy Policy; 2578public: 2579 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2580 const PrintingPolicy &Policy) 2581 : OS(os), Helper(helper), Policy(Policy) {} 2582 2583 void VisitIfStmt(IfStmt* I) { 2584 OS << "if "; 2585 I->getCond()->printPretty(OS,Helper,Policy); 2586 } 2587 2588 // Default case. 2589 void VisitStmt(Stmt* Terminator) { 2590 Terminator->printPretty(OS, Helper, Policy); 2591 } 2592 2593 void VisitForStmt(ForStmt* F) { 2594 OS << "for (" ; 2595 if (F->getInit()) 2596 OS << "..."; 2597 OS << "; "; 2598 if (Stmt* C = F->getCond()) 2599 C->printPretty(OS, Helper, Policy); 2600 OS << "; "; 2601 if (F->getInc()) 2602 OS << "..."; 2603 OS << ")"; 2604 } 2605 2606 void VisitWhileStmt(WhileStmt* W) { 2607 OS << "while " ; 2608 if (Stmt* C = W->getCond()) 2609 C->printPretty(OS, Helper, Policy); 2610 } 2611 2612 void VisitDoStmt(DoStmt* D) { 2613 OS << "do ... while "; 2614 if (Stmt* C = D->getCond()) 2615 C->printPretty(OS, Helper, Policy); 2616 } 2617 2618 void VisitSwitchStmt(SwitchStmt* Terminator) { 2619 OS << "switch "; 2620 Terminator->getCond()->printPretty(OS, Helper, Policy); 2621 } 2622 2623 void VisitCXXTryStmt(CXXTryStmt* CS) { 2624 OS << "try ..."; 2625 } 2626 2627 void VisitConditionalOperator(ConditionalOperator* C) { 2628 C->getCond()->printPretty(OS, Helper, Policy); 2629 OS << " ? ... : ..."; 2630 } 2631 2632 void VisitChooseExpr(ChooseExpr* C) { 2633 OS << "__builtin_choose_expr( "; 2634 C->getCond()->printPretty(OS, Helper, Policy); 2635 OS << " )"; 2636 } 2637 2638 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2639 OS << "goto *"; 2640 I->getTarget()->printPretty(OS, Helper, Policy); 2641 } 2642 2643 void VisitBinaryOperator(BinaryOperator* B) { 2644 if (!B->isLogicalOp()) { 2645 VisitExpr(B); 2646 return; 2647 } 2648 2649 B->getLHS()->printPretty(OS, Helper, Policy); 2650 2651 switch (B->getOpcode()) { 2652 case BO_LOr: 2653 OS << " || ..."; 2654 return; 2655 case BO_LAnd: 2656 OS << " && ..."; 2657 return; 2658 default: 2659 assert(false && "Invalid logical operator."); 2660 } 2661 } 2662 2663 void VisitExpr(Expr* E) { 2664 E->printPretty(OS, Helper, Policy); 2665 } 2666}; 2667} // end anonymous namespace 2668 2669static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2670 const CFGElement &E) { 2671 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2672 Stmt *S = CS; 2673 2674 if (Helper) { 2675 2676 // special printing for statement-expressions. 2677 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2678 CompoundStmt* Sub = SE->getSubStmt(); 2679 2680 if (Sub->child_begin() != Sub->child_end()) { 2681 OS << "({ ... ; "; 2682 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2683 OS << " })\n"; 2684 return; 2685 } 2686 } 2687 // special printing for comma expressions. 2688 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2689 if (B->getOpcode() == BO_Comma) { 2690 OS << "... , "; 2691 Helper->handledStmt(B->getRHS(),OS); 2692 OS << '\n'; 2693 return; 2694 } 2695 } 2696 } 2697 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2698 2699 if (isa<CXXOperatorCallExpr>(S)) { 2700 OS << " (OperatorCall)"; 2701 } 2702 else if (isa<CXXBindTemporaryExpr>(S)) { 2703 OS << " (BindTemporary)"; 2704 } 2705 2706 // Expressions need a newline. 2707 if (isa<Expr>(S)) 2708 OS << '\n'; 2709 2710 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2711 CXXBaseOrMemberInitializer* I = IE; 2712 if (I->isBaseInitializer()) 2713 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2714 else OS << I->getMember()->getName(); 2715 2716 OS << "("; 2717 if (Expr* IE = I->getInit()) 2718 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2719 OS << ")"; 2720 2721 if (I->isBaseInitializer()) 2722 OS << " (Base initializer)\n"; 2723 else OS << " (Member initializer)\n"; 2724 2725 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2726 VarDecl* VD = DE.getVarDecl(); 2727 Helper->handleDecl(VD, OS); 2728 2729 const Type* T = VD->getType().getTypePtr(); 2730 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2731 T = RT->getPointeeType().getTypePtr(); 2732 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 2733 T = ET; 2734 2735 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2736 OS << " (Implicit destructor)\n"; 2737 2738 } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { 2739 const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); 2740 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 2741 OS << " (Base object destructor)\n"; 2742 2743 } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { 2744 FieldDecl *FD = ME.getFieldDecl(); 2745 2746 const Type *T = FD->getType().getTypePtr(); 2747 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 2748 T = ET; 2749 2750 OS << "this->" << FD->getName(); 2751 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 2752 OS << " (Member object destructor)\n"; 2753 } 2754 } 2755 2756static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2757 const CFGBlock& B, 2758 StmtPrinterHelper* Helper, bool print_edges) { 2759 2760 if (Helper) Helper->setBlockID(B.getBlockID()); 2761 2762 // Print the header. 2763 OS << "\n [ B" << B.getBlockID(); 2764 2765 if (&B == &cfg->getEntry()) 2766 OS << " (ENTRY) ]\n"; 2767 else if (&B == &cfg->getExit()) 2768 OS << " (EXIT) ]\n"; 2769 else if (&B == cfg->getIndirectGotoBlock()) 2770 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2771 else 2772 OS << " ]\n"; 2773 2774 // Print the label of this block. 2775 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2776 2777 if (print_edges) 2778 OS << " "; 2779 2780 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2781 OS << L->getName(); 2782 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2783 OS << "case "; 2784 C->getLHS()->printPretty(OS, Helper, 2785 PrintingPolicy(Helper->getLangOpts())); 2786 if (C->getRHS()) { 2787 OS << " ... "; 2788 C->getRHS()->printPretty(OS, Helper, 2789 PrintingPolicy(Helper->getLangOpts())); 2790 } 2791 } else if (isa<DefaultStmt>(Label)) 2792 OS << "default"; 2793 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2794 OS << "catch ("; 2795 if (CS->getExceptionDecl()) 2796 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2797 0); 2798 else 2799 OS << "..."; 2800 OS << ")"; 2801 2802 } else 2803 assert(false && "Invalid label statement in CFGBlock."); 2804 2805 OS << ":\n"; 2806 } 2807 2808 // Iterate through the statements in the block and print them. 2809 unsigned j = 1; 2810 2811 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2812 I != E ; ++I, ++j ) { 2813 2814 // Print the statement # in the basic block and the statement itself. 2815 if (print_edges) 2816 OS << " "; 2817 2818 OS << llvm::format("%3d", j) << ": "; 2819 2820 if (Helper) 2821 Helper->setStmtID(j); 2822 2823 print_elem(OS,Helper,*I); 2824 } 2825 2826 // Print the terminator of this block. 2827 if (B.getTerminator()) { 2828 if (print_edges) 2829 OS << " "; 2830 2831 OS << " T: "; 2832 2833 if (Helper) Helper->setBlockID(-1); 2834 2835 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2836 PrintingPolicy(Helper->getLangOpts())); 2837 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2838 OS << '\n'; 2839 } 2840 2841 if (print_edges) { 2842 // Print the predecessors of this block. 2843 OS << " Predecessors (" << B.pred_size() << "):"; 2844 unsigned i = 0; 2845 2846 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2847 I != E; ++I, ++i) { 2848 2849 if (i == 8 || (i-8) == 0) 2850 OS << "\n "; 2851 2852 OS << " B" << (*I)->getBlockID(); 2853 } 2854 2855 OS << '\n'; 2856 2857 // Print the successors of this block. 2858 OS << " Successors (" << B.succ_size() << "):"; 2859 i = 0; 2860 2861 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2862 I != E; ++I, ++i) { 2863 2864 if (i == 8 || (i-8) % 10 == 0) 2865 OS << "\n "; 2866 2867 if (*I) 2868 OS << " B" << (*I)->getBlockID(); 2869 else 2870 OS << " NULL"; 2871 } 2872 2873 OS << '\n'; 2874 } 2875} 2876 2877 2878/// dump - A simple pretty printer of a CFG that outputs to stderr. 2879void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2880 2881/// print - A simple pretty printer of a CFG that outputs to an ostream. 2882void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2883 StmtPrinterHelper Helper(this, LO); 2884 2885 // Print the entry block. 2886 print_block(OS, this, getEntry(), &Helper, true); 2887 2888 // Iterate through the CFGBlocks and print them one by one. 2889 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2890 // Skip the entry block, because we already printed it. 2891 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2892 continue; 2893 2894 print_block(OS, this, **I, &Helper, true); 2895 } 2896 2897 // Print the exit block. 2898 print_block(OS, this, getExit(), &Helper, true); 2899 OS.flush(); 2900} 2901 2902/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2903void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2904 print(llvm::errs(), cfg, LO); 2905} 2906 2907/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2908/// Generally this will only be called from CFG::print. 2909void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2910 const LangOptions &LO) const { 2911 StmtPrinterHelper Helper(cfg, LO); 2912 print_block(OS, cfg, *this, &Helper, true); 2913} 2914 2915/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2916void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2917 const LangOptions &LO) const { 2918 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2919 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2920} 2921 2922Stmt* CFGBlock::getTerminatorCondition() { 2923 2924 if (!Terminator) 2925 return NULL; 2926 2927 Expr* E = NULL; 2928 2929 switch (Terminator->getStmtClass()) { 2930 default: 2931 break; 2932 2933 case Stmt::ForStmtClass: 2934 E = cast<ForStmt>(Terminator)->getCond(); 2935 break; 2936 2937 case Stmt::WhileStmtClass: 2938 E = cast<WhileStmt>(Terminator)->getCond(); 2939 break; 2940 2941 case Stmt::DoStmtClass: 2942 E = cast<DoStmt>(Terminator)->getCond(); 2943 break; 2944 2945 case Stmt::IfStmtClass: 2946 E = cast<IfStmt>(Terminator)->getCond(); 2947 break; 2948 2949 case Stmt::ChooseExprClass: 2950 E = cast<ChooseExpr>(Terminator)->getCond(); 2951 break; 2952 2953 case Stmt::IndirectGotoStmtClass: 2954 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2955 break; 2956 2957 case Stmt::SwitchStmtClass: 2958 E = cast<SwitchStmt>(Terminator)->getCond(); 2959 break; 2960 2961 case Stmt::ConditionalOperatorClass: 2962 E = cast<ConditionalOperator>(Terminator)->getCond(); 2963 break; 2964 2965 case Stmt::BinaryOperatorClass: // '&&' and '||' 2966 E = cast<BinaryOperator>(Terminator)->getLHS(); 2967 break; 2968 2969 case Stmt::ObjCForCollectionStmtClass: 2970 return Terminator; 2971 } 2972 2973 return E ? E->IgnoreParens() : NULL; 2974} 2975 2976bool CFGBlock::hasBinaryBranchTerminator() const { 2977 2978 if (!Terminator) 2979 return false; 2980 2981 Expr* E = NULL; 2982 2983 switch (Terminator->getStmtClass()) { 2984 default: 2985 return false; 2986 2987 case Stmt::ForStmtClass: 2988 case Stmt::WhileStmtClass: 2989 case Stmt::DoStmtClass: 2990 case Stmt::IfStmtClass: 2991 case Stmt::ChooseExprClass: 2992 case Stmt::ConditionalOperatorClass: 2993 case Stmt::BinaryOperatorClass: 2994 return true; 2995 } 2996 2997 return E ? E->IgnoreParens() : NULL; 2998} 2999 3000 3001//===----------------------------------------------------------------------===// 3002// CFG Graphviz Visualization 3003//===----------------------------------------------------------------------===// 3004 3005 3006#ifndef NDEBUG 3007static StmtPrinterHelper* GraphHelper; 3008#endif 3009 3010void CFG::viewCFG(const LangOptions &LO) const { 3011#ifndef NDEBUG 3012 StmtPrinterHelper H(this, LO); 3013 GraphHelper = &H; 3014 llvm::ViewGraph(this,"CFG"); 3015 GraphHelper = NULL; 3016#endif 3017} 3018 3019namespace llvm { 3020template<> 3021struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3022 3023 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3024 3025 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3026 3027#ifndef NDEBUG 3028 std::string OutSStr; 3029 llvm::raw_string_ostream Out(OutSStr); 3030 print_block(Out,Graph, *Node, GraphHelper, false); 3031 std::string& OutStr = Out.str(); 3032 3033 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3034 3035 // Process string output to make it nicer... 3036 for (unsigned i = 0; i != OutStr.length(); ++i) 3037 if (OutStr[i] == '\n') { // Left justify 3038 OutStr[i] = '\\'; 3039 OutStr.insert(OutStr.begin()+i+1, 'l'); 3040 } 3041 3042 return OutStr; 3043#else 3044 return ""; 3045#endif 3046 } 3047}; 3048} // end namespace llvm 3049