CFG.cpp revision 82bc3fd823d85ee3ef9a641c0975b6ad25f55047
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); 310 311 // Local scopes creation. 312 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 313 314 void addLocalScopeForStmt(Stmt* S); 315 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 316 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 317 318 void addLocalScopeAndDtors(Stmt* S); 319 320 // Interface to CFGBlock - adding CFGElements. 321 void AppendStmt(CFGBlock *B, Stmt *S, 322 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 323 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 324 } 325 void appendInitializer(CFGBlock *B, CXXBaseOrMemberInitializer *I) { 326 B->appendInitializer(I, cfg->getBumpVectorContext()); 327 } 328 329 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 330 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 331 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 332 LocalScope::const_iterator E, Stmt* S); 333 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 334 LocalScope::const_iterator B, LocalScope::const_iterator E); 335 336 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 337 B->addSuccessor(S, cfg->getBumpVectorContext()); 338 } 339 340 /// TryResult - a class representing a variant over the values 341 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 342 /// and is used by the CFGBuilder to decide if a branch condition 343 /// can be decided up front during CFG construction. 344 class TryResult { 345 int X; 346 public: 347 TryResult(bool b) : X(b ? 1 : 0) {} 348 TryResult() : X(-1) {} 349 350 bool isTrue() const { return X == 1; } 351 bool isFalse() const { return X == 0; } 352 bool isKnown() const { return X >= 0; } 353 void negate() { 354 assert(isKnown()); 355 X ^= 0x1; 356 } 357 }; 358 359 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 360 /// if we can evaluate to a known value, otherwise return -1. 361 TryResult TryEvaluateBool(Expr *S) { 362 if (!BuildOpts.PruneTriviallyFalseEdges) 363 return TryResult(); 364 365 Expr::EvalResult Result; 366 if (!S->isTypeDependent() && !S->isValueDependent() && 367 S->Evaluate(Result, *Context) && Result.Val.isInt()) 368 return Result.Val.getInt().getBoolValue(); 369 370 return TryResult(); 371 } 372}; 373 374// FIXME: Add support for dependent-sized array types in C++? 375// Does it even make sense to build a CFG for an uninstantiated template? 376static VariableArrayType* FindVA(Type* t) { 377 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 378 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 379 if (vat->getSizeExpr()) 380 return vat; 381 382 t = vt->getElementType().getTypePtr(); 383 } 384 385 return 0; 386} 387 388/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 389/// arbitrary statement. Examples include a single expression or a function 390/// body (compound statement). The ownership of the returned CFG is 391/// transferred to the caller. If CFG construction fails, this method returns 392/// NULL. 393CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 394 CFG::BuildOptions BO) { 395 396 Context = C; 397 assert(cfg.get()); 398 if (!Statement) 399 return NULL; 400 401 BuildOpts = BO; 402 403 // Create an empty block that will serve as the exit block for the CFG. Since 404 // this is the first block added to the CFG, it will be implicitly registered 405 // as the exit block. 406 Succ = createBlock(); 407 assert(Succ == &cfg->getExit()); 408 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 409 410 // Visit the statements and create the CFG. 411 CFGBlock *B = addStmt(Statement); 412 413 if (badCFG) 414 return NULL; 415 416 // For C++ constructor add initializers to CFG. 417 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 418 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 419 E = CD->init_rend(); I != E; ++I) { 420 B = addInitializer(*I); 421 if (badCFG) 422 return NULL; 423 } 424 } 425 426 if (B) 427 Succ = B; 428 429 // Backpatch the gotos whose label -> block mappings we didn't know when we 430 // encountered them. 431 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 432 E = BackpatchBlocks.end(); I != E; ++I ) { 433 434 CFGBlock* B = I->Block; 435 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 436 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 437 438 // If there is no target for the goto, then we are looking at an 439 // incomplete AST. Handle this by not registering a successor. 440 if (LI == LabelMap.end()) continue; 441 442 JumpTarget JT = LI->second; 443 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 444 AddSuccessor(B, JT.Block); 445 } 446 447 // Add successors to the Indirect Goto Dispatch block (if we have one). 448 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 449 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 450 E = AddressTakenLabels.end(); I != E; ++I ) { 451 452 // Lookup the target block. 453 LabelMapTy::iterator LI = LabelMap.find(*I); 454 455 // If there is no target block that contains label, then we are looking 456 // at an incomplete AST. Handle this by not registering a successor. 457 if (LI == LabelMap.end()) continue; 458 459 AddSuccessor(B, LI->second.Block); 460 } 461 462 // Create an empty entry block that has no predecessors. 463 cfg->setEntry(createBlock()); 464 465 return cfg.take(); 466} 467 468/// createBlock - Used to lazily create blocks that are connected 469/// to the current (global) succcessor. 470CFGBlock* CFGBuilder::createBlock(bool add_successor) { 471 CFGBlock* B = cfg->createBlock(); 472 if (add_successor && Succ) 473 AddSuccessor(B, Succ); 474 return B; 475} 476 477/// addInitializer - Add C++ base or member initializer element to CFG. 478CFGBlock *CFGBuilder::addInitializer(CXXBaseOrMemberInitializer *I) { 479 if (!BuildOpts.AddInitializers) 480 return Block; 481 482 autoCreateBlock(); 483 appendInitializer(Block, I); 484 485 if (Expr *Init = I->getInit()) { 486 AddStmtChoice::Kind K = AddStmtChoice::NotAlwaysAdd; 487 if (FieldDecl *FD = I->getMember()) 488 if (FD->getType()->isReferenceType()) 489 K = AddStmtChoice::AsLValueNotAlwaysAdd; 490 491 return Visit(Init, AddStmtChoice(K)); 492 } 493 494 return Block; 495} 496 497/// addAutomaticObjDtors - Add to current block automatic objects destructors 498/// for objects in range of local scope positions. Use S as trigger statement 499/// for destructors. 500void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 501 LocalScope::const_iterator E, Stmt* S) { 502 if (!BuildOpts.AddImplicitDtors) 503 return; 504 505 if (B == E) 506 return; 507 508 autoCreateBlock(); 509 appendAutomaticObjDtors(Block, B, E, S); 510} 511 512/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 513/// way return valid LocalScope object. 514LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 515 if (!Scope) { 516 Scope = cfg->getAllocator().Allocate<LocalScope>(); 517 new (Scope) LocalScope(ScopePos); 518 } 519 return Scope; 520} 521 522/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 523/// that should create implicit scope (e.g. if/else substatements). 524void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 525 if (!BuildOpts.AddImplicitDtors) 526 return; 527 528 LocalScope *Scope = 0; 529 530 // For compound statement we will be creating explicit scope. 531 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 532 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 533 ; BI != BE; ++BI) { 534 Stmt* SI = *BI; 535 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 536 SI = LS->getSubStmt(); 537 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 538 Scope = addLocalScopeForDeclStmt(DS, Scope); 539 } 540 return; 541 } 542 543 // For any other statement scope will be implicit and as such will be 544 // interesting only for DeclStmt. 545 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 546 S = LS->getSubStmt(); 547 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 548 addLocalScopeForDeclStmt(DS); 549} 550 551/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 552/// reuse Scope if not NULL. 553LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 554 LocalScope* Scope) { 555 if (!BuildOpts.AddImplicitDtors) 556 return Scope; 557 558 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 559 ; DI != DE; ++DI) { 560 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 561 Scope = addLocalScopeForVarDecl(VD, Scope); 562 } 563 return Scope; 564} 565 566/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 567/// create add scope for automatic objects and temporary objects bound to 568/// const reference. Will reuse Scope if not NULL. 569LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 570 LocalScope* Scope) { 571 if (!BuildOpts.AddImplicitDtors) 572 return Scope; 573 574 // Check if variable is local. 575 switch (VD->getStorageClass()) { 576 case SC_None: 577 case SC_Auto: 578 case SC_Register: 579 break; 580 default: return Scope; 581 } 582 583 // Check for const references bound to temporary. Set type to pointee. 584 QualType QT = VD->getType(); 585 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 586 QT = RT->getPointeeType(); 587 if (!QT.isConstQualified()) 588 return Scope; 589 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 590 return Scope; 591 } 592 593 // Check if type is a C++ class with non-trivial destructor. 594 if (const RecordType* RT = QT.getTypePtr()->getAs<RecordType>()) 595 if (const CXXRecordDecl* CD = dyn_cast<CXXRecordDecl>(RT->getDecl())) 596 if (!CD->hasTrivialDestructor()) { 597 // Add the variable to scope 598 Scope = createOrReuseLocalScope(Scope); 599 Scope->addVar(VD); 600 ScopePos = Scope->begin(); 601 } 602 return Scope; 603} 604 605/// addLocalScopeAndDtors - For given statement add local scope for it and 606/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 607void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 608 if (!BuildOpts.AddImplicitDtors) 609 return; 610 611 LocalScope::const_iterator scopeBeginPos = ScopePos; 612 addLocalScopeForStmt(S); 613 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 614} 615 616/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 617/// automatic storage duration to CFGBlock's elements vector. Insertion will be 618/// performed in place specified with iterator. 619void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 620 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 621 BumpVectorContext& C = cfg->getBumpVectorContext(); 622 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 623 while (B != E) 624 I = Blk->insertAutomaticObjDtor(I, *B++, S); 625} 626 627/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 628/// automatic storage duration to CFGBlock's elements vector. Elements will be 629/// appended to physical end of the vector which happens to be logical 630/// beginning. 631void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 632 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 633 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 634} 635 636/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 637/// variables with automatic storage duration to CFGBlock's elements vector. 638/// Elements will be prepended to physical beginning of the vector which 639/// happens to be logical end. Use blocks terminator as statement that specifies 640/// destructors call site. 641void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 642 LocalScope::const_iterator B, LocalScope::const_iterator E) { 643 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 644} 645 646/// Visit - Walk the subtree of a statement and add extra 647/// blocks for ternary operators, &&, and ||. We also process "," and 648/// DeclStmts (which may contain nested control-flow). 649CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 650tryAgain: 651 if (!S) { 652 badCFG = true; 653 return 0; 654 } 655 switch (S->getStmtClass()) { 656 default: 657 return VisitStmt(S, asc); 658 659 case Stmt::AddrLabelExprClass: 660 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 661 662 case Stmt::BinaryOperatorClass: 663 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 664 665 case Stmt::BlockExprClass: 666 return VisitBlockExpr(cast<BlockExpr>(S), asc); 667 668 case Stmt::BreakStmtClass: 669 return VisitBreakStmt(cast<BreakStmt>(S)); 670 671 case Stmt::CallExprClass: 672 case Stmt::CXXOperatorCallExprClass: 673 return VisitCallExpr(cast<CallExpr>(S), asc); 674 675 case Stmt::CaseStmtClass: 676 return VisitCaseStmt(cast<CaseStmt>(S)); 677 678 case Stmt::ChooseExprClass: 679 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 680 681 case Stmt::CompoundStmtClass: 682 return VisitCompoundStmt(cast<CompoundStmt>(S)); 683 684 case Stmt::ConditionalOperatorClass: 685 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 686 687 case Stmt::ContinueStmtClass: 688 return VisitContinueStmt(cast<ContinueStmt>(S)); 689 690 case Stmt::CXXCatchStmtClass: 691 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 692 693 case Stmt::CXXExprWithTemporariesClass: { 694 // FIXME: Handle temporaries. For now, just visit the subexpression 695 // so we don't artificially create extra blocks. 696 return Visit(cast<CXXExprWithTemporaries>(S)->getSubExpr(), asc); 697 } 698 699 case Stmt::CXXMemberCallExprClass: 700 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 701 702 case Stmt::CXXThrowExprClass: 703 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 704 705 case Stmt::CXXTryStmtClass: 706 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 707 708 case Stmt::DeclStmtClass: 709 return VisitDeclStmt(cast<DeclStmt>(S)); 710 711 case Stmt::DefaultStmtClass: 712 return VisitDefaultStmt(cast<DefaultStmt>(S)); 713 714 case Stmt::DoStmtClass: 715 return VisitDoStmt(cast<DoStmt>(S)); 716 717 case Stmt::ForStmtClass: 718 return VisitForStmt(cast<ForStmt>(S)); 719 720 case Stmt::GotoStmtClass: 721 return VisitGotoStmt(cast<GotoStmt>(S)); 722 723 case Stmt::IfStmtClass: 724 return VisitIfStmt(cast<IfStmt>(S)); 725 726 case Stmt::IndirectGotoStmtClass: 727 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 728 729 case Stmt::LabelStmtClass: 730 return VisitLabelStmt(cast<LabelStmt>(S)); 731 732 case Stmt::MemberExprClass: 733 return VisitMemberExpr(cast<MemberExpr>(S), asc); 734 735 case Stmt::ObjCAtCatchStmtClass: 736 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 737 738 case Stmt::ObjCAtSynchronizedStmtClass: 739 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 740 741 case Stmt::ObjCAtThrowStmtClass: 742 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 743 744 case Stmt::ObjCAtTryStmtClass: 745 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 746 747 case Stmt::ObjCForCollectionStmtClass: 748 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 749 750 case Stmt::ParenExprClass: 751 S = cast<ParenExpr>(S)->getSubExpr(); 752 goto tryAgain; 753 754 case Stmt::NullStmtClass: 755 return Block; 756 757 case Stmt::ReturnStmtClass: 758 return VisitReturnStmt(cast<ReturnStmt>(S)); 759 760 case Stmt::SizeOfAlignOfExprClass: 761 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 762 763 case Stmt::StmtExprClass: 764 return VisitStmtExpr(cast<StmtExpr>(S), asc); 765 766 case Stmt::SwitchStmtClass: 767 return VisitSwitchStmt(cast<SwitchStmt>(S)); 768 769 case Stmt::WhileStmtClass: 770 return VisitWhileStmt(cast<WhileStmt>(S)); 771 } 772} 773 774CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 775 if (asc.alwaysAdd()) { 776 autoCreateBlock(); 777 AppendStmt(Block, S, asc); 778 } 779 780 return VisitChildren(S); 781} 782 783/// VisitChildren - Visit the children of a Stmt. 784CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 785 CFGBlock *B = Block; 786 for (Stmt::child_iterator I = Terminator->child_begin(), 787 E = Terminator->child_end(); I != E; ++I) { 788 if (*I) B = Visit(*I); 789 } 790 return B; 791} 792 793CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 794 AddStmtChoice asc) { 795 AddressTakenLabels.insert(A->getLabel()); 796 797 if (asc.alwaysAdd()) { 798 autoCreateBlock(); 799 AppendStmt(Block, A, asc); 800 } 801 802 return Block; 803} 804 805CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 806 AddStmtChoice asc) { 807 if (B->isLogicalOp()) { // && or || 808 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 809 AppendStmt(ConfluenceBlock, B, asc); 810 811 if (badCFG) 812 return 0; 813 814 // create the block evaluating the LHS 815 CFGBlock* LHSBlock = createBlock(false); 816 LHSBlock->setTerminator(B); 817 818 // create the block evaluating the RHS 819 Succ = ConfluenceBlock; 820 Block = NULL; 821 CFGBlock* RHSBlock = addStmt(B->getRHS()); 822 823 if (RHSBlock) { 824 if (badCFG) 825 return 0; 826 } 827 else { 828 // Create an empty block for cases where the RHS doesn't require 829 // any explicit statements in the CFG. 830 RHSBlock = createBlock(); 831 } 832 833 // See if this is a known constant. 834 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 835 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 836 KnownVal.negate(); 837 838 // Now link the LHSBlock with RHSBlock. 839 if (B->getOpcode() == BO_LOr) { 840 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 841 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 842 } else { 843 assert(B->getOpcode() == BO_LAnd); 844 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 845 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 846 } 847 848 // Generate the blocks for evaluating the LHS. 849 Block = LHSBlock; 850 return addStmt(B->getLHS()); 851 } 852 else if (B->getOpcode() == BO_Comma) { // , 853 autoCreateBlock(); 854 AppendStmt(Block, B, asc); 855 addStmt(B->getRHS()); 856 return addStmt(B->getLHS()); 857 } 858 else if (B->isAssignmentOp()) { 859 if (asc.alwaysAdd()) { 860 autoCreateBlock(); 861 AppendStmt(Block, B, asc); 862 } 863 864 // If visiting RHS causes us to finish 'Block' and the LHS doesn't 865 // create a new block, then we should return RBlock. Otherwise 866 // we'll incorrectly return NULL. 867 CFGBlock *RBlock = Visit(B->getRHS()); 868 CFGBlock *LBlock = Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 869 return LBlock ? LBlock : RBlock; 870 } 871 872 return VisitStmt(B, asc); 873} 874 875CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 876 if (asc.alwaysAdd()) { 877 autoCreateBlock(); 878 AppendStmt(Block, E, asc); 879 } 880 return Block; 881} 882 883CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 884 // "break" is a control-flow statement. Thus we stop processing the current 885 // block. 886 if (badCFG) 887 return 0; 888 889 // Now create a new block that ends with the break statement. 890 Block = createBlock(false); 891 Block->setTerminator(B); 892 893 // If there is no target for the break, then we are looking at an incomplete 894 // AST. This means that the CFG cannot be constructed. 895 if (BreakJumpTarget.Block) { 896 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 897 AddSuccessor(Block, BreakJumpTarget.Block); 898 } else 899 badCFG = true; 900 901 902 return Block; 903} 904 905static bool CanThrow(Expr *E) { 906 QualType Ty = E->getType(); 907 if (Ty->isFunctionPointerType()) 908 Ty = Ty->getAs<PointerType>()->getPointeeType(); 909 else if (Ty->isBlockPointerType()) 910 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 911 912 const FunctionType *FT = Ty->getAs<FunctionType>(); 913 if (FT) { 914 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 915 if (Proto->hasEmptyExceptionSpec()) 916 return false; 917 } 918 return true; 919} 920 921CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 922 // If this is a call to a no-return function, this stops the block here. 923 bool NoReturn = false; 924 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 925 NoReturn = true; 926 } 927 928 bool AddEHEdge = false; 929 930 // Languages without exceptions are assumed to not throw. 931 if (Context->getLangOptions().Exceptions) { 932 if (BuildOpts.AddEHEdges) 933 AddEHEdge = true; 934 } 935 936 if (FunctionDecl *FD = C->getDirectCallee()) { 937 if (FD->hasAttr<NoReturnAttr>()) 938 NoReturn = true; 939 if (FD->hasAttr<NoThrowAttr>()) 940 AddEHEdge = false; 941 } 942 943 if (!CanThrow(C->getCallee())) 944 AddEHEdge = false; 945 946 if (!NoReturn && !AddEHEdge) { 947 if (asc.asLValue()) 948 return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue); 949 else 950 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 951 } 952 953 if (Block) { 954 Succ = Block; 955 if (badCFG) 956 return 0; 957 } 958 959 Block = createBlock(!NoReturn); 960 AppendStmt(Block, C, asc); 961 962 if (NoReturn) { 963 // Wire this to the exit block directly. 964 AddSuccessor(Block, &cfg->getExit()); 965 } 966 if (AddEHEdge) { 967 // Add exceptional edges. 968 if (TryTerminatedBlock) 969 AddSuccessor(Block, TryTerminatedBlock); 970 else 971 AddSuccessor(Block, &cfg->getExit()); 972 } 973 974 return VisitChildren(C); 975} 976 977CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 978 AddStmtChoice asc) { 979 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 980 AppendStmt(ConfluenceBlock, C, asc); 981 if (badCFG) 982 return 0; 983 984 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 985 : AddStmtChoice::AlwaysAdd; 986 987 Succ = ConfluenceBlock; 988 Block = NULL; 989 CFGBlock* LHSBlock = Visit(C->getLHS(), asc); 990 if (badCFG) 991 return 0; 992 993 Succ = ConfluenceBlock; 994 Block = NULL; 995 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 996 if (badCFG) 997 return 0; 998 999 Block = createBlock(false); 1000 // See if this is a known constant. 1001 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1002 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1003 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1004 Block->setTerminator(C); 1005 return addStmt(C->getCond()); 1006} 1007 1008 1009CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1010 addLocalScopeAndDtors(C); 1011 CFGBlock* LastBlock = Block; 1012 1013 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1014 I != E; ++I ) { 1015 // If we hit a segment of code just containing ';' (NullStmts), we can 1016 // get a null block back. In such cases, just use the LastBlock 1017 if (CFGBlock *newBlock = addStmt(*I)) 1018 LastBlock = newBlock; 1019 1020 if (badCFG) 1021 return NULL; 1022 } 1023 1024 return LastBlock; 1025} 1026 1027CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1028 AddStmtChoice asc) { 1029 // Create the confluence block that will "merge" the results of the ternary 1030 // expression. 1031 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1032 AppendStmt(ConfluenceBlock, C, asc); 1033 if (badCFG) 1034 return 0; 1035 1036 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1037 : AddStmtChoice::AlwaysAdd; 1038 1039 // Create a block for the LHS expression if there is an LHS expression. A 1040 // GCC extension allows LHS to be NULL, causing the condition to be the 1041 // value that is returned instead. 1042 // e.g: x ?: y is shorthand for: x ? x : y; 1043 Succ = ConfluenceBlock; 1044 Block = NULL; 1045 CFGBlock* LHSBlock = NULL; 1046 if (C->getLHS()) { 1047 LHSBlock = Visit(C->getLHS(), asc); 1048 if (badCFG) 1049 return 0; 1050 Block = NULL; 1051 } 1052 1053 // Create the block for the RHS expression. 1054 Succ = ConfluenceBlock; 1055 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1056 if (badCFG) 1057 return 0; 1058 1059 // Create the block that will contain the condition. 1060 Block = createBlock(false); 1061 1062 // See if this is a known constant. 1063 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1064 if (LHSBlock) { 1065 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1066 } else { 1067 if (KnownVal.isFalse()) { 1068 // If we know the condition is false, add NULL as the successor for 1069 // the block containing the condition. In this case, the confluence 1070 // block will have just one predecessor. 1071 AddSuccessor(Block, 0); 1072 assert(ConfluenceBlock->pred_size() == 1); 1073 } else { 1074 // If we have no LHS expression, add the ConfluenceBlock as a direct 1075 // successor for the block containing the condition. Moreover, we need to 1076 // reverse the order of the predecessors in the ConfluenceBlock because 1077 // the RHSBlock will have been added to the succcessors already, and we 1078 // want the first predecessor to the the block containing the expression 1079 // for the case when the ternary expression evaluates to true. 1080 AddSuccessor(Block, ConfluenceBlock); 1081 assert(ConfluenceBlock->pred_size() == 2); 1082 std::reverse(ConfluenceBlock->pred_begin(), 1083 ConfluenceBlock->pred_end()); 1084 } 1085 } 1086 1087 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1088 Block->setTerminator(C); 1089 return addStmt(C->getCond()); 1090} 1091 1092CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1093 autoCreateBlock(); 1094 1095 if (DS->isSingleDecl()) { 1096 AppendStmt(Block, DS); 1097 return VisitDeclSubExpr(DS->getSingleDecl()); 1098 } 1099 1100 CFGBlock *B = 0; 1101 1102 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1103 typedef llvm::SmallVector<Decl*,10> BufTy; 1104 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1105 1106 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1107 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1108 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1109 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1110 1111 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1112 // automatically freed with the CFG. 1113 DeclGroupRef DG(*I); 1114 Decl *D = *I; 1115 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1116 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1117 1118 // Append the fake DeclStmt to block. 1119 AppendStmt(Block, DSNew); 1120 B = VisitDeclSubExpr(D); 1121 } 1122 1123 return B; 1124} 1125 1126/// VisitDeclSubExpr - Utility method to add block-level expressions for 1127/// initializers in Decls. 1128CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 1129 assert(Block); 1130 1131 VarDecl *VD = dyn_cast<VarDecl>(D); 1132 1133 if (!VD) 1134 return Block; 1135 1136 Expr *Init = VD->getInit(); 1137 1138 if (Init) { 1139 AddStmtChoice::Kind k = 1140 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 1141 : AddStmtChoice::NotAlwaysAdd; 1142 Visit(Init, AddStmtChoice(k)); 1143 } 1144 1145 // If the type of VD is a VLA, then we must process its size expressions. 1146 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1147 VA = FindVA(VA->getElementType().getTypePtr())) 1148 Block = addStmt(VA->getSizeExpr()); 1149 1150 // Remove variable from local scope. 1151 if (ScopePos && VD == *ScopePos) 1152 ++ScopePos; 1153 1154 return Block; 1155} 1156 1157CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1158 // We may see an if statement in the middle of a basic block, or it may be the 1159 // first statement we are processing. In either case, we create a new basic 1160 // block. First, we create the blocks for the then...else statements, and 1161 // then we create the block containing the if statement. If we were in the 1162 // middle of a block, we stop processing that block. That block is then the 1163 // implicit successor for the "then" and "else" clauses. 1164 1165 // Save local scope position because in case of condition variable ScopePos 1166 // won't be restored when traversing AST. 1167 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1168 1169 // Create local scope for possible condition variable. 1170 // Store scope position. Add implicit destructor. 1171 if (VarDecl* VD = I->getConditionVariable()) { 1172 LocalScope::const_iterator BeginScopePos = ScopePos; 1173 addLocalScopeForVarDecl(VD); 1174 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1175 } 1176 1177 // The block we were proccessing is now finished. Make it the successor 1178 // block. 1179 if (Block) { 1180 Succ = Block; 1181 if (badCFG) 1182 return 0; 1183 } 1184 1185 // Process the false branch. 1186 CFGBlock* ElseBlock = Succ; 1187 1188 if (Stmt* Else = I->getElse()) { 1189 SaveAndRestore<CFGBlock*> sv(Succ); 1190 1191 // NULL out Block so that the recursive call to Visit will 1192 // create a new basic block. 1193 Block = NULL; 1194 1195 // If branch is not a compound statement create implicit scope 1196 // and add destructors. 1197 if (!isa<CompoundStmt>(Else)) 1198 addLocalScopeAndDtors(Else); 1199 1200 ElseBlock = addStmt(Else); 1201 1202 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1203 ElseBlock = sv.get(); 1204 else if (Block) { 1205 if (badCFG) 1206 return 0; 1207 } 1208 } 1209 1210 // Process the true branch. 1211 CFGBlock* ThenBlock; 1212 { 1213 Stmt* Then = I->getThen(); 1214 assert(Then); 1215 SaveAndRestore<CFGBlock*> sv(Succ); 1216 Block = NULL; 1217 1218 // If branch is not a compound statement create implicit scope 1219 // and add destructors. 1220 if (!isa<CompoundStmt>(Then)) 1221 addLocalScopeAndDtors(Then); 1222 1223 ThenBlock = addStmt(Then); 1224 1225 if (!ThenBlock) { 1226 // We can reach here if the "then" body has all NullStmts. 1227 // Create an empty block so we can distinguish between true and false 1228 // branches in path-sensitive analyses. 1229 ThenBlock = createBlock(false); 1230 AddSuccessor(ThenBlock, sv.get()); 1231 } else if (Block) { 1232 if (badCFG) 1233 return 0; 1234 } 1235 } 1236 1237 // Now create a new block containing the if statement. 1238 Block = createBlock(false); 1239 1240 // Set the terminator of the new block to the If statement. 1241 Block->setTerminator(I); 1242 1243 // See if this is a known constant. 1244 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1245 1246 // Now add the successors. 1247 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1248 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1249 1250 // Add the condition as the last statement in the new block. This may create 1251 // new blocks as the condition may contain control-flow. Any newly created 1252 // blocks will be pointed to be "Block". 1253 Block = addStmt(I->getCond()); 1254 1255 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1256 // and the condition variable initialization to the CFG. 1257 if (VarDecl *VD = I->getConditionVariable()) { 1258 if (Expr *Init = VD->getInit()) { 1259 autoCreateBlock(); 1260 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1261 addStmt(Init); 1262 } 1263 } 1264 1265 return Block; 1266} 1267 1268 1269CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1270 // If we were in the middle of a block we stop processing that block. 1271 // 1272 // NOTE: If a "return" appears in the middle of a block, this means that the 1273 // code afterwards is DEAD (unreachable). We still keep a basic block 1274 // for that code; a simple "mark-and-sweep" from the entry block will be 1275 // able to report such dead blocks. 1276 1277 // Create the new block. 1278 Block = createBlock(false); 1279 1280 // The Exit block is the only successor. 1281 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1282 AddSuccessor(Block, &cfg->getExit()); 1283 1284 // Add the return statement to the block. This may create new blocks if R 1285 // contains control-flow (short-circuit operations). 1286 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1287} 1288 1289CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1290 // Get the block of the labeled statement. Add it to our map. 1291 addStmt(L->getSubStmt()); 1292 CFGBlock* LabelBlock = Block; 1293 1294 if (!LabelBlock) // This can happen when the body is empty, i.e. 1295 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1296 1297 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1298 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1299 1300 // Labels partition blocks, so this is the end of the basic block we were 1301 // processing (L is the block's label). Because this is label (and we have 1302 // already processed the substatement) there is no extra control-flow to worry 1303 // about. 1304 LabelBlock->setLabel(L); 1305 if (badCFG) 1306 return 0; 1307 1308 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1309 Block = NULL; 1310 1311 // This block is now the implicit successor of other blocks. 1312 Succ = LabelBlock; 1313 1314 return LabelBlock; 1315} 1316 1317CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1318 // Goto is a control-flow statement. Thus we stop processing the current 1319 // block and create a new one. 1320 1321 Block = createBlock(false); 1322 Block->setTerminator(G); 1323 1324 // If we already know the mapping to the label block add the successor now. 1325 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1326 1327 if (I == LabelMap.end()) 1328 // We will need to backpatch this block later. 1329 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1330 else { 1331 JumpTarget JT = I->second; 1332 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1333 AddSuccessor(Block, JT.Block); 1334 } 1335 1336 return Block; 1337} 1338 1339CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1340 CFGBlock* LoopSuccessor = NULL; 1341 1342 // Save local scope position because in case of condition variable ScopePos 1343 // won't be restored when traversing AST. 1344 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1345 1346 // Create local scope for init statement and possible condition variable. 1347 // Add destructor for init statement and condition variable. 1348 // Store scope position for continue statement. 1349 if (Stmt* Init = F->getInit()) 1350 addLocalScopeForStmt(Init); 1351 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1352 1353 if (VarDecl* VD = F->getConditionVariable()) 1354 addLocalScopeForVarDecl(VD); 1355 LocalScope::const_iterator ContinueScopePos = ScopePos; 1356 1357 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1358 1359 // "for" is a control-flow statement. Thus we stop processing the current 1360 // block. 1361 if (Block) { 1362 if (badCFG) 1363 return 0; 1364 LoopSuccessor = Block; 1365 } else 1366 LoopSuccessor = Succ; 1367 1368 // Save the current value for the break targets. 1369 // All breaks should go to the code following the loop. 1370 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1371 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1372 1373 // Because of short-circuit evaluation, the condition of the loop can span 1374 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1375 // evaluate the condition. 1376 CFGBlock* ExitConditionBlock = createBlock(false); 1377 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1378 1379 // Set the terminator for the "exit" condition block. 1380 ExitConditionBlock->setTerminator(F); 1381 1382 // Now add the actual condition to the condition block. Because the condition 1383 // itself may contain control-flow, new blocks may be created. 1384 if (Stmt* C = F->getCond()) { 1385 Block = ExitConditionBlock; 1386 EntryConditionBlock = addStmt(C); 1387 assert(Block == EntryConditionBlock || 1388 (Block == 0 && EntryConditionBlock == Succ)); 1389 1390 // If this block contains a condition variable, add both the condition 1391 // variable and initializer to the CFG. 1392 if (VarDecl *VD = F->getConditionVariable()) { 1393 if (Expr *Init = VD->getInit()) { 1394 autoCreateBlock(); 1395 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1396 EntryConditionBlock = addStmt(Init); 1397 assert(Block == EntryConditionBlock); 1398 } 1399 } 1400 1401 if (Block) { 1402 if (badCFG) 1403 return 0; 1404 } 1405 } 1406 1407 // The condition block is the implicit successor for the loop body as well as 1408 // any code above the loop. 1409 Succ = EntryConditionBlock; 1410 1411 // See if this is a known constant. 1412 TryResult KnownVal(true); 1413 1414 if (F->getCond()) 1415 KnownVal = TryEvaluateBool(F->getCond()); 1416 1417 // Now create the loop body. 1418 { 1419 assert(F->getBody()); 1420 1421 // Save the current values for Block, Succ, and continue targets. 1422 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1423 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1424 1425 // Create a new block to contain the (bottom) of the loop body. 1426 Block = NULL; 1427 1428 // Loop body should end with destructor of Condition variable (if any). 1429 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1430 1431 if (Stmt* I = F->getInc()) { 1432 // Generate increment code in its own basic block. This is the target of 1433 // continue statements. 1434 Succ = addStmt(I); 1435 } else { 1436 // No increment code. Create a special, empty, block that is used as the 1437 // target block for "looping back" to the start of the loop. 1438 assert(Succ == EntryConditionBlock); 1439 Succ = Block ? Block : createBlock(); 1440 } 1441 1442 // Finish up the increment (or empty) block if it hasn't been already. 1443 if (Block) { 1444 assert(Block == Succ); 1445 if (badCFG) 1446 return 0; 1447 Block = 0; 1448 } 1449 1450 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1451 1452 // The starting block for the loop increment is the block that should 1453 // represent the 'loop target' for looping back to the start of the loop. 1454 ContinueJumpTarget.Block->setLoopTarget(F); 1455 1456 // If body is not a compound statement create implicit scope 1457 // and add destructors. 1458 if (!isa<CompoundStmt>(F->getBody())) 1459 addLocalScopeAndDtors(F->getBody()); 1460 1461 // Now populate the body block, and in the process create new blocks as we 1462 // walk the body of the loop. 1463 CFGBlock* BodyBlock = addStmt(F->getBody()); 1464 1465 if (!BodyBlock) 1466 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1467 else if (badCFG) 1468 return 0; 1469 1470 // This new body block is a successor to our "exit" condition block. 1471 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1472 } 1473 1474 // Link up the condition block with the code that follows the loop. (the 1475 // false branch). 1476 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1477 1478 // If the loop contains initialization, create a new block for those 1479 // statements. This block can also contain statements that precede the loop. 1480 if (Stmt* I = F->getInit()) { 1481 Block = createBlock(); 1482 return addStmt(I); 1483 } else { 1484 // There is no loop initialization. We are thus basically a while loop. 1485 // NULL out Block to force lazy block construction. 1486 Block = NULL; 1487 Succ = EntryConditionBlock; 1488 return EntryConditionBlock; 1489 } 1490} 1491 1492CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1493 if (asc.alwaysAdd()) { 1494 autoCreateBlock(); 1495 AppendStmt(Block, M, asc); 1496 } 1497 return Visit(M->getBase(), 1498 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1499 : AddStmtChoice::AsLValueNotAlwaysAdd); 1500} 1501 1502CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1503 // Objective-C fast enumeration 'for' statements: 1504 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1505 // 1506 // for ( Type newVariable in collection_expression ) { statements } 1507 // 1508 // becomes: 1509 // 1510 // prologue: 1511 // 1. collection_expression 1512 // T. jump to loop_entry 1513 // loop_entry: 1514 // 1. side-effects of element expression 1515 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1516 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1517 // TB: 1518 // statements 1519 // T. jump to loop_entry 1520 // FB: 1521 // what comes after 1522 // 1523 // and 1524 // 1525 // Type existingItem; 1526 // for ( existingItem in expression ) { statements } 1527 // 1528 // becomes: 1529 // 1530 // the same with newVariable replaced with existingItem; the binding works 1531 // the same except that for one ObjCForCollectionStmt::getElement() returns 1532 // a DeclStmt and the other returns a DeclRefExpr. 1533 // 1534 1535 CFGBlock* LoopSuccessor = 0; 1536 1537 if (Block) { 1538 if (badCFG) 1539 return 0; 1540 LoopSuccessor = Block; 1541 Block = 0; 1542 } else 1543 LoopSuccessor = Succ; 1544 1545 // Build the condition blocks. 1546 CFGBlock* ExitConditionBlock = createBlock(false); 1547 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1548 1549 // Set the terminator for the "exit" condition block. 1550 ExitConditionBlock->setTerminator(S); 1551 1552 // The last statement in the block should be the ObjCForCollectionStmt, which 1553 // performs the actual binding to 'element' and determines if there are any 1554 // more items in the collection. 1555 AppendStmt(ExitConditionBlock, S); 1556 Block = ExitConditionBlock; 1557 1558 // Walk the 'element' expression to see if there are any side-effects. We 1559 // generate new blocks as necesary. We DON'T add the statement by default to 1560 // the CFG unless it contains control-flow. 1561 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1562 if (Block) { 1563 if (badCFG) 1564 return 0; 1565 Block = 0; 1566 } 1567 1568 // The condition block is the implicit successor for the loop body as well as 1569 // any code above the loop. 1570 Succ = EntryConditionBlock; 1571 1572 // Now create the true branch. 1573 { 1574 // Save the current values for Succ, continue and break targets. 1575 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1576 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1577 save_break(BreakJumpTarget); 1578 1579 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1580 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1581 1582 CFGBlock* BodyBlock = addStmt(S->getBody()); 1583 1584 if (!BodyBlock) 1585 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1586 else if (Block) { 1587 if (badCFG) 1588 return 0; 1589 } 1590 1591 // This new body block is a successor to our "exit" condition block. 1592 AddSuccessor(ExitConditionBlock, BodyBlock); 1593 } 1594 1595 // Link up the condition block with the code that follows the loop. 1596 // (the false branch). 1597 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1598 1599 // Now create a prologue block to contain the collection expression. 1600 Block = createBlock(); 1601 return addStmt(S->getCollection()); 1602} 1603 1604CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1605 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1606 1607 // Inline the body. 1608 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1609 1610 // The sync body starts its own basic block. This makes it a little easier 1611 // for diagnostic clients. 1612 if (SyncBlock) { 1613 if (badCFG) 1614 return 0; 1615 1616 Block = 0; 1617 Succ = SyncBlock; 1618 } 1619 1620 // Add the @synchronized to the CFG. 1621 autoCreateBlock(); 1622 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1623 1624 // Inline the sync expression. 1625 return addStmt(S->getSynchExpr()); 1626} 1627 1628CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1629 // FIXME 1630 return NYS(); 1631} 1632 1633CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1634 CFGBlock* LoopSuccessor = NULL; 1635 1636 // Save local scope position because in case of condition variable ScopePos 1637 // won't be restored when traversing AST. 1638 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1639 1640 // Create local scope for possible condition variable. 1641 // Store scope position for continue statement. 1642 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1643 if (VarDecl* VD = W->getConditionVariable()) { 1644 addLocalScopeForVarDecl(VD); 1645 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1646 } 1647 1648 // "while" is a control-flow statement. Thus we stop processing the current 1649 // block. 1650 if (Block) { 1651 if (badCFG) 1652 return 0; 1653 LoopSuccessor = Block; 1654 } else 1655 LoopSuccessor = Succ; 1656 1657 // Because of short-circuit evaluation, the condition of the loop can span 1658 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1659 // evaluate the condition. 1660 CFGBlock* ExitConditionBlock = createBlock(false); 1661 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1662 1663 // Set the terminator for the "exit" condition block. 1664 ExitConditionBlock->setTerminator(W); 1665 1666 // Now add the actual condition to the condition block. Because the condition 1667 // itself may contain control-flow, new blocks may be created. Thus we update 1668 // "Succ" after adding the condition. 1669 if (Stmt* C = W->getCond()) { 1670 Block = ExitConditionBlock; 1671 EntryConditionBlock = addStmt(C); 1672 assert(Block == EntryConditionBlock); 1673 1674 // If this block contains a condition variable, add both the condition 1675 // variable and initializer to the CFG. 1676 if (VarDecl *VD = W->getConditionVariable()) { 1677 if (Expr *Init = VD->getInit()) { 1678 autoCreateBlock(); 1679 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1680 EntryConditionBlock = addStmt(Init); 1681 assert(Block == EntryConditionBlock); 1682 } 1683 } 1684 1685 if (Block) { 1686 if (badCFG) 1687 return 0; 1688 } 1689 } 1690 1691 // The condition block is the implicit successor for the loop body as well as 1692 // any code above the loop. 1693 Succ = EntryConditionBlock; 1694 1695 // See if this is a known constant. 1696 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1697 1698 // Process the loop body. 1699 { 1700 assert(W->getBody()); 1701 1702 // Save the current values for Block, Succ, and continue and break targets 1703 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1704 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1705 save_break(BreakJumpTarget); 1706 1707 // Create an empty block to represent the transition block for looping back 1708 // to the head of the loop. 1709 Block = 0; 1710 assert(Succ == EntryConditionBlock); 1711 Succ = createBlock(); 1712 Succ->setLoopTarget(W); 1713 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1714 1715 // All breaks should go to the code following the loop. 1716 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1717 1718 // NULL out Block to force lazy instantiation of blocks for the body. 1719 Block = NULL; 1720 1721 // Loop body should end with destructor of Condition variable (if any). 1722 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1723 1724 // If body is not a compound statement create implicit scope 1725 // and add destructors. 1726 if (!isa<CompoundStmt>(W->getBody())) 1727 addLocalScopeAndDtors(W->getBody()); 1728 1729 // Create the body. The returned block is the entry to the loop body. 1730 CFGBlock* BodyBlock = addStmt(W->getBody()); 1731 1732 if (!BodyBlock) 1733 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1734 else if (Block) { 1735 if (badCFG) 1736 return 0; 1737 } 1738 1739 // Add the loop body entry as a successor to the condition. 1740 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1741 } 1742 1743 // Link up the condition block with the code that follows the loop. (the 1744 // false branch). 1745 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1746 1747 // There can be no more statements in the condition block since we loop back 1748 // to this block. NULL out Block to force lazy creation of another block. 1749 Block = NULL; 1750 1751 // Return the condition block, which is the dominating block for the loop. 1752 Succ = EntryConditionBlock; 1753 return EntryConditionBlock; 1754} 1755 1756 1757CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1758 // FIXME: For now we pretend that @catch and the code it contains does not 1759 // exit. 1760 return Block; 1761} 1762 1763CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1764 // FIXME: This isn't complete. We basically treat @throw like a return 1765 // statement. 1766 1767 // If we were in the middle of a block we stop processing that block. 1768 if (badCFG) 1769 return 0; 1770 1771 // Create the new block. 1772 Block = createBlock(false); 1773 1774 // The Exit block is the only successor. 1775 AddSuccessor(Block, &cfg->getExit()); 1776 1777 // Add the statement to the block. This may create new blocks if S contains 1778 // control-flow (short-circuit operations). 1779 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1780} 1781 1782CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1783 // If we were in the middle of a block we stop processing that block. 1784 if (badCFG) 1785 return 0; 1786 1787 // Create the new block. 1788 Block = createBlock(false); 1789 1790 if (TryTerminatedBlock) 1791 // The current try statement is the only successor. 1792 AddSuccessor(Block, TryTerminatedBlock); 1793 else 1794 // otherwise the Exit block is the only successor. 1795 AddSuccessor(Block, &cfg->getExit()); 1796 1797 // Add the statement to the block. This may create new blocks if S contains 1798 // control-flow (short-circuit operations). 1799 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1800} 1801 1802CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1803 CFGBlock* LoopSuccessor = NULL; 1804 1805 // "do...while" is a control-flow statement. Thus we stop processing the 1806 // current block. 1807 if (Block) { 1808 if (badCFG) 1809 return 0; 1810 LoopSuccessor = Block; 1811 } else 1812 LoopSuccessor = Succ; 1813 1814 // Because of short-circuit evaluation, the condition of the loop can span 1815 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1816 // evaluate the condition. 1817 CFGBlock* ExitConditionBlock = createBlock(false); 1818 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1819 1820 // Set the terminator for the "exit" condition block. 1821 ExitConditionBlock->setTerminator(D); 1822 1823 // Now add the actual condition to the condition block. Because the condition 1824 // itself may contain control-flow, new blocks may be created. 1825 if (Stmt* C = D->getCond()) { 1826 Block = ExitConditionBlock; 1827 EntryConditionBlock = addStmt(C); 1828 if (Block) { 1829 if (badCFG) 1830 return 0; 1831 } 1832 } 1833 1834 // The condition block is the implicit successor for the loop body. 1835 Succ = EntryConditionBlock; 1836 1837 // See if this is a known constant. 1838 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1839 1840 // Process the loop body. 1841 CFGBlock* BodyBlock = NULL; 1842 { 1843 assert(D->getBody()); 1844 1845 // Save the current values for Block, Succ, and continue and break targets 1846 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1847 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1848 save_break(BreakJumpTarget); 1849 1850 // All continues within this loop should go to the condition block 1851 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1852 1853 // All breaks should go to the code following the loop. 1854 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1855 1856 // NULL out Block to force lazy instantiation of blocks for the body. 1857 Block = NULL; 1858 1859 // If body is not a compound statement create implicit scope 1860 // and add destructors. 1861 if (!isa<CompoundStmt>(D->getBody())) 1862 addLocalScopeAndDtors(D->getBody()); 1863 1864 // Create the body. The returned block is the entry to the loop body. 1865 BodyBlock = addStmt(D->getBody()); 1866 1867 if (!BodyBlock) 1868 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1869 else if (Block) { 1870 if (badCFG) 1871 return 0; 1872 } 1873 1874 if (!KnownVal.isFalse()) { 1875 // Add an intermediate block between the BodyBlock and the 1876 // ExitConditionBlock to represent the "loop back" transition. Create an 1877 // empty block to represent the transition block for looping back to the 1878 // head of the loop. 1879 // FIXME: Can we do this more efficiently without adding another block? 1880 Block = NULL; 1881 Succ = BodyBlock; 1882 CFGBlock *LoopBackBlock = createBlock(); 1883 LoopBackBlock->setLoopTarget(D); 1884 1885 // Add the loop body entry as a successor to the condition. 1886 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1887 } 1888 else 1889 AddSuccessor(ExitConditionBlock, NULL); 1890 } 1891 1892 // Link up the condition block with the code that follows the loop. 1893 // (the false branch). 1894 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1895 1896 // There can be no more statements in the body block(s) since we loop back to 1897 // the body. NULL out Block to force lazy creation of another block. 1898 Block = NULL; 1899 1900 // Return the loop body, which is the dominating block for the loop. 1901 Succ = BodyBlock; 1902 return BodyBlock; 1903} 1904 1905CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1906 // "continue" is a control-flow statement. Thus we stop processing the 1907 // current block. 1908 if (badCFG) 1909 return 0; 1910 1911 // Now create a new block that ends with the continue statement. 1912 Block = createBlock(false); 1913 Block->setTerminator(C); 1914 1915 // If there is no target for the continue, then we are looking at an 1916 // incomplete AST. This means the CFG cannot be constructed. 1917 if (ContinueJumpTarget.Block) { 1918 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1919 AddSuccessor(Block, ContinueJumpTarget.Block); 1920 } else 1921 badCFG = true; 1922 1923 return Block; 1924} 1925 1926CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1927 AddStmtChoice asc) { 1928 1929 if (asc.alwaysAdd()) { 1930 autoCreateBlock(); 1931 AppendStmt(Block, E); 1932 } 1933 1934 // VLA types have expressions that must be evaluated. 1935 if (E->isArgumentType()) { 1936 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1937 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1938 addStmt(VA->getSizeExpr()); 1939 } 1940 1941 return Block; 1942} 1943 1944/// VisitStmtExpr - Utility method to handle (nested) statement 1945/// expressions (a GCC extension). 1946CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 1947 if (asc.alwaysAdd()) { 1948 autoCreateBlock(); 1949 AppendStmt(Block, SE); 1950 } 1951 return VisitCompoundStmt(SE->getSubStmt()); 1952} 1953 1954CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1955 // "switch" is a control-flow statement. Thus we stop processing the current 1956 // block. 1957 CFGBlock* SwitchSuccessor = NULL; 1958 1959 // Save local scope position because in case of condition variable ScopePos 1960 // won't be restored when traversing AST. 1961 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1962 1963 // Create local scope for possible condition variable. 1964 // Store scope position. Add implicit destructor. 1965 if (VarDecl* VD = Terminator->getConditionVariable()) { 1966 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 1967 addLocalScopeForVarDecl(VD); 1968 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 1969 } 1970 1971 if (Block) { 1972 if (badCFG) 1973 return 0; 1974 SwitchSuccessor = Block; 1975 } else SwitchSuccessor = Succ; 1976 1977 // Save the current "switch" context. 1978 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1979 save_default(DefaultCaseBlock); 1980 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1981 1982 // Set the "default" case to be the block after the switch statement. If the 1983 // switch statement contains a "default:", this value will be overwritten with 1984 // the block for that code. 1985 DefaultCaseBlock = SwitchSuccessor; 1986 1987 // Create a new block that will contain the switch statement. 1988 SwitchTerminatedBlock = createBlock(false); 1989 1990 // Now process the switch body. The code after the switch is the implicit 1991 // successor. 1992 Succ = SwitchSuccessor; 1993 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 1994 1995 // When visiting the body, the case statements should automatically get linked 1996 // up to the switch. We also don't keep a pointer to the body, since all 1997 // control-flow from the switch goes to case/default statements. 1998 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 1999 Block = NULL; 2000 2001 // If body is not a compound statement create implicit scope 2002 // and add destructors. 2003 if (!isa<CompoundStmt>(Terminator->getBody())) 2004 addLocalScopeAndDtors(Terminator->getBody()); 2005 2006 addStmt(Terminator->getBody()); 2007 if (Block) { 2008 if (badCFG) 2009 return 0; 2010 } 2011 2012 // If we have no "default:" case, the default transition is to the code 2013 // following the switch body. 2014 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2015 2016 // Add the terminator and condition in the switch block. 2017 SwitchTerminatedBlock->setTerminator(Terminator); 2018 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2019 Block = SwitchTerminatedBlock; 2020 Block = addStmt(Terminator->getCond()); 2021 2022 // Finally, if the SwitchStmt contains a condition variable, add both the 2023 // SwitchStmt and the condition variable initialization to the CFG. 2024 if (VarDecl *VD = Terminator->getConditionVariable()) { 2025 if (Expr *Init = VD->getInit()) { 2026 autoCreateBlock(); 2027 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2028 addStmt(Init); 2029 } 2030 } 2031 2032 return Block; 2033} 2034 2035CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2036 // CaseStmts are essentially labels, so they are the first statement in a 2037 // block. 2038 CFGBlock *TopBlock = 0, *LastBlock = 0; 2039 2040 if (Stmt *Sub = CS->getSubStmt()) { 2041 // For deeply nested chains of CaseStmts, instead of doing a recursion 2042 // (which can blow out the stack), manually unroll and create blocks 2043 // along the way. 2044 while (isa<CaseStmt>(Sub)) { 2045 CFGBlock *CurrentBlock = createBlock(false); 2046 CurrentBlock->setLabel(CS); 2047 2048 if (TopBlock) 2049 AddSuccessor(LastBlock, CurrentBlock); 2050 else 2051 TopBlock = CurrentBlock; 2052 2053 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2054 LastBlock = CurrentBlock; 2055 2056 CS = cast<CaseStmt>(Sub); 2057 Sub = CS->getSubStmt(); 2058 } 2059 2060 addStmt(Sub); 2061 } 2062 2063 CFGBlock* CaseBlock = Block; 2064 if (!CaseBlock) 2065 CaseBlock = createBlock(); 2066 2067 // Cases statements partition blocks, so this is the top of the basic block we 2068 // were processing (the "case XXX:" is the label). 2069 CaseBlock->setLabel(CS); 2070 2071 if (badCFG) 2072 return 0; 2073 2074 // Add this block to the list of successors for the block with the switch 2075 // statement. 2076 assert(SwitchTerminatedBlock); 2077 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2078 2079 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2080 Block = NULL; 2081 2082 if (TopBlock) { 2083 AddSuccessor(LastBlock, CaseBlock); 2084 Succ = TopBlock; 2085 } 2086 else { 2087 // This block is now the implicit successor of other blocks. 2088 Succ = CaseBlock; 2089 } 2090 2091 return Succ; 2092} 2093 2094CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2095 if (Terminator->getSubStmt()) 2096 addStmt(Terminator->getSubStmt()); 2097 2098 DefaultCaseBlock = Block; 2099 2100 if (!DefaultCaseBlock) 2101 DefaultCaseBlock = createBlock(); 2102 2103 // Default statements partition blocks, so this is the top of the basic block 2104 // we were processing (the "default:" is the label). 2105 DefaultCaseBlock->setLabel(Terminator); 2106 2107 if (badCFG) 2108 return 0; 2109 2110 // Unlike case statements, we don't add the default block to the successors 2111 // for the switch statement immediately. This is done when we finish 2112 // processing the switch statement. This allows for the default case 2113 // (including a fall-through to the code after the switch statement) to always 2114 // be the last successor of a switch-terminated block. 2115 2116 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2117 Block = NULL; 2118 2119 // This block is now the implicit successor of other blocks. 2120 Succ = DefaultCaseBlock; 2121 2122 return DefaultCaseBlock; 2123} 2124 2125CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2126 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2127 // current block. 2128 CFGBlock* TrySuccessor = NULL; 2129 2130 if (Block) { 2131 if (badCFG) 2132 return 0; 2133 TrySuccessor = Block; 2134 } else TrySuccessor = Succ; 2135 2136 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2137 2138 // Create a new block that will contain the try statement. 2139 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2140 // Add the terminator in the try block. 2141 NewTryTerminatedBlock->setTerminator(Terminator); 2142 2143 bool HasCatchAll = false; 2144 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2145 // The code after the try is the implicit successor. 2146 Succ = TrySuccessor; 2147 CXXCatchStmt *CS = Terminator->getHandler(h); 2148 if (CS->getExceptionDecl() == 0) { 2149 HasCatchAll = true; 2150 } 2151 Block = NULL; 2152 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2153 if (CatchBlock == 0) 2154 return 0; 2155 // Add this block to the list of successors for the block with the try 2156 // statement. 2157 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2158 } 2159 if (!HasCatchAll) { 2160 if (PrevTryTerminatedBlock) 2161 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2162 else 2163 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2164 } 2165 2166 // The code after the try is the implicit successor. 2167 Succ = TrySuccessor; 2168 2169 // Save the current "try" context. 2170 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2171 TryTerminatedBlock = NewTryTerminatedBlock; 2172 2173 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2174 Block = NULL; 2175 Block = addStmt(Terminator->getTryBlock()); 2176 return Block; 2177} 2178 2179CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2180 // CXXCatchStmt are treated like labels, so they are the first statement in a 2181 // block. 2182 2183 // Save local scope position because in case of exception variable ScopePos 2184 // won't be restored when traversing AST. 2185 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2186 2187 // Create local scope for possible exception variable. 2188 // Store scope position. Add implicit destructor. 2189 if (VarDecl* VD = CS->getExceptionDecl()) { 2190 LocalScope::const_iterator BeginScopePos = ScopePos; 2191 addLocalScopeForVarDecl(VD); 2192 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2193 } 2194 2195 if (CS->getHandlerBlock()) 2196 addStmt(CS->getHandlerBlock()); 2197 2198 CFGBlock* CatchBlock = Block; 2199 if (!CatchBlock) 2200 CatchBlock = createBlock(); 2201 2202 CatchBlock->setLabel(CS); 2203 2204 if (badCFG) 2205 return 0; 2206 2207 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2208 Block = NULL; 2209 2210 return CatchBlock; 2211} 2212 2213CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2214 AddStmtChoice asc) { 2215 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2216 : AddStmtChoice::AlwaysAdd; 2217 autoCreateBlock(); 2218 AppendStmt(Block, C, AddStmtChoice(K)); 2219 return VisitChildren(C); 2220} 2221 2222CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2223 // Lazily create the indirect-goto dispatch block if there isn't one already. 2224 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2225 2226 if (!IBlock) { 2227 IBlock = createBlock(false); 2228 cfg->setIndirectGotoBlock(IBlock); 2229 } 2230 2231 // IndirectGoto is a control-flow statement. Thus we stop processing the 2232 // current block and create a new one. 2233 if (badCFG) 2234 return 0; 2235 2236 Block = createBlock(false); 2237 Block->setTerminator(I); 2238 AddSuccessor(Block, IBlock); 2239 return addStmt(I->getTarget()); 2240} 2241 2242} // end anonymous namespace 2243 2244/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2245/// no successors or predecessors. If this is the first block created in the 2246/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2247CFGBlock* CFG::createBlock() { 2248 bool first_block = begin() == end(); 2249 2250 // Create the block. 2251 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2252 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2253 Blocks.push_back(Mem, BlkBVC); 2254 2255 // If this is the first block, set it as the Entry and Exit. 2256 if (first_block) 2257 Entry = Exit = &back(); 2258 2259 // Return the block. 2260 return &back(); 2261} 2262 2263/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2264/// CFG is returned to the caller. 2265CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2266 BuildOptions BO) { 2267 CFGBuilder Builder; 2268 return Builder.buildCFG(D, Statement, C, BO); 2269} 2270 2271//===----------------------------------------------------------------------===// 2272// CFG: Queries for BlkExprs. 2273//===----------------------------------------------------------------------===// 2274 2275namespace { 2276 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2277} 2278 2279static void FindSubExprAssignments(Stmt *S, 2280 llvm::SmallPtrSet<Expr*,50>& Set) { 2281 if (!S) 2282 return; 2283 2284 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2285 Stmt *child = *I; 2286 if (!child) 2287 continue; 2288 2289 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2290 if (B->isAssignmentOp()) Set.insert(B); 2291 2292 FindSubExprAssignments(child, Set); 2293 } 2294} 2295 2296static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2297 BlkExprMapTy* M = new BlkExprMapTy(); 2298 2299 // Look for assignments that are used as subexpressions. These are the only 2300 // assignments that we want to *possibly* register as a block-level 2301 // expression. Basically, if an assignment occurs both in a subexpression and 2302 // at the block-level, it is a block-level expression. 2303 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2304 2305 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2306 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2307 if (CFGStmt S = BI->getAs<CFGStmt>()) 2308 FindSubExprAssignments(S, SubExprAssignments); 2309 2310 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2311 2312 // Iterate over the statements again on identify the Expr* and Stmt* at the 2313 // block-level that are block-level expressions. 2314 2315 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2316 CFGStmt CS = BI->getAs<CFGStmt>(); 2317 if (!CS.isValid()) 2318 continue; 2319 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2320 2321 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2322 // Assignment expressions that are not nested within another 2323 // expression are really "statements" whose value is never used by 2324 // another expression. 2325 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2326 continue; 2327 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2328 // Special handling for statement expressions. The last statement in 2329 // the statement expression is also a block-level expr. 2330 const CompoundStmt* C = Terminator->getSubStmt(); 2331 if (!C->body_empty()) { 2332 unsigned x = M->size(); 2333 (*M)[C->body_back()] = x; 2334 } 2335 } 2336 2337 unsigned x = M->size(); 2338 (*M)[Exp] = x; 2339 } 2340 } 2341 2342 // Look at terminators. The condition is a block-level expression. 2343 2344 Stmt* S = (*I)->getTerminatorCondition(); 2345 2346 if (S && M->find(S) == M->end()) { 2347 unsigned x = M->size(); 2348 (*M)[S] = x; 2349 } 2350 } 2351 2352 return M; 2353} 2354 2355CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2356 assert(S != NULL); 2357 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2358 2359 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2360 BlkExprMapTy::iterator I = M->find(S); 2361 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2362} 2363 2364unsigned CFG::getNumBlkExprs() { 2365 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2366 return M->size(); 2367 else { 2368 // We assume callers interested in the number of BlkExprs will want 2369 // the map constructed if it doesn't already exist. 2370 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2371 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2372 } 2373} 2374 2375//===----------------------------------------------------------------------===// 2376// Filtered walking of the CFG. 2377//===----------------------------------------------------------------------===// 2378 2379bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2380 const CFGBlock *From, const CFGBlock *To) { 2381 2382 if (F.IgnoreDefaultsWithCoveredEnums) { 2383 // If the 'To' has no label or is labeled but the label isn't a 2384 // CaseStmt then filter this edge. 2385 if (const SwitchStmt *S = 2386 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2387 if (S->isAllEnumCasesCovered()) { 2388 const Stmt *L = To->getLabel(); 2389 if (!L || !isa<CaseStmt>(L)) 2390 return true; 2391 } 2392 } 2393 } 2394 2395 return false; 2396} 2397 2398//===----------------------------------------------------------------------===// 2399// Cleanup: CFG dstor. 2400//===----------------------------------------------------------------------===// 2401 2402CFG::~CFG() { 2403 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2404} 2405 2406//===----------------------------------------------------------------------===// 2407// CFG pretty printing 2408//===----------------------------------------------------------------------===// 2409 2410namespace { 2411 2412class StmtPrinterHelper : public PrinterHelper { 2413 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2414 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2415 StmtMapTy StmtMap; 2416 DeclMapTy DeclMap; 2417 signed CurrentBlock; 2418 unsigned CurrentStmt; 2419 const LangOptions &LangOpts; 2420public: 2421 2422 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2423 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2424 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2425 unsigned j = 1; 2426 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2427 BI != BEnd; ++BI, ++j ) { 2428 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2429 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2430 StmtMap[SE] = P; 2431 2432 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2433 DeclMap[DS->getSingleDecl()] = P; 2434 2435 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2436 if (VarDecl* VD = IS->getConditionVariable()) 2437 DeclMap[VD] = P; 2438 2439 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2440 if (VarDecl* VD = FS->getConditionVariable()) 2441 DeclMap[VD] = P; 2442 2443 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2444 if (VarDecl* VD = WS->getConditionVariable()) 2445 DeclMap[VD] = P; 2446 2447 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2448 if (VarDecl* VD = SS->getConditionVariable()) 2449 DeclMap[VD] = P; 2450 2451 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2452 if (VarDecl* VD = CS->getExceptionDecl()) 2453 DeclMap[VD] = P; 2454 } 2455 } 2456 } 2457 } 2458 } 2459 2460 virtual ~StmtPrinterHelper() {} 2461 2462 const LangOptions &getLangOpts() const { return LangOpts; } 2463 void setBlockID(signed i) { CurrentBlock = i; } 2464 void setStmtID(unsigned i) { CurrentStmt = i; } 2465 2466 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2467 StmtMapTy::iterator I = StmtMap.find(S); 2468 2469 if (I == StmtMap.end()) 2470 return false; 2471 2472 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2473 && I->second.second == CurrentStmt) { 2474 return false; 2475 } 2476 2477 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2478 return true; 2479 } 2480 2481 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2482 DeclMapTy::iterator I = DeclMap.find(D); 2483 2484 if (I == DeclMap.end()) 2485 return false; 2486 2487 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2488 && I->second.second == CurrentStmt) { 2489 return false; 2490 } 2491 2492 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2493 return true; 2494 } 2495}; 2496} // end anonymous namespace 2497 2498 2499namespace { 2500class CFGBlockTerminatorPrint 2501 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2502 2503 llvm::raw_ostream& OS; 2504 StmtPrinterHelper* Helper; 2505 PrintingPolicy Policy; 2506public: 2507 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2508 const PrintingPolicy &Policy) 2509 : OS(os), Helper(helper), Policy(Policy) {} 2510 2511 void VisitIfStmt(IfStmt* I) { 2512 OS << "if "; 2513 I->getCond()->printPretty(OS,Helper,Policy); 2514 } 2515 2516 // Default case. 2517 void VisitStmt(Stmt* Terminator) { 2518 Terminator->printPretty(OS, Helper, Policy); 2519 } 2520 2521 void VisitForStmt(ForStmt* F) { 2522 OS << "for (" ; 2523 if (F->getInit()) 2524 OS << "..."; 2525 OS << "; "; 2526 if (Stmt* C = F->getCond()) 2527 C->printPretty(OS, Helper, Policy); 2528 OS << "; "; 2529 if (F->getInc()) 2530 OS << "..."; 2531 OS << ")"; 2532 } 2533 2534 void VisitWhileStmt(WhileStmt* W) { 2535 OS << "while " ; 2536 if (Stmt* C = W->getCond()) 2537 C->printPretty(OS, Helper, Policy); 2538 } 2539 2540 void VisitDoStmt(DoStmt* D) { 2541 OS << "do ... while "; 2542 if (Stmt* C = D->getCond()) 2543 C->printPretty(OS, Helper, Policy); 2544 } 2545 2546 void VisitSwitchStmt(SwitchStmt* Terminator) { 2547 OS << "switch "; 2548 Terminator->getCond()->printPretty(OS, Helper, Policy); 2549 } 2550 2551 void VisitCXXTryStmt(CXXTryStmt* CS) { 2552 OS << "try ..."; 2553 } 2554 2555 void VisitConditionalOperator(ConditionalOperator* C) { 2556 C->getCond()->printPretty(OS, Helper, Policy); 2557 OS << " ? ... : ..."; 2558 } 2559 2560 void VisitChooseExpr(ChooseExpr* C) { 2561 OS << "__builtin_choose_expr( "; 2562 C->getCond()->printPretty(OS, Helper, Policy); 2563 OS << " )"; 2564 } 2565 2566 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2567 OS << "goto *"; 2568 I->getTarget()->printPretty(OS, Helper, Policy); 2569 } 2570 2571 void VisitBinaryOperator(BinaryOperator* B) { 2572 if (!B->isLogicalOp()) { 2573 VisitExpr(B); 2574 return; 2575 } 2576 2577 B->getLHS()->printPretty(OS, Helper, Policy); 2578 2579 switch (B->getOpcode()) { 2580 case BO_LOr: 2581 OS << " || ..."; 2582 return; 2583 case BO_LAnd: 2584 OS << " && ..."; 2585 return; 2586 default: 2587 assert(false && "Invalid logical operator."); 2588 } 2589 } 2590 2591 void VisitExpr(Expr* E) { 2592 E->printPretty(OS, Helper, Policy); 2593 } 2594}; 2595} // end anonymous namespace 2596 2597static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2598 const CFGElement &E) { 2599 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2600 Stmt *S = CS; 2601 2602 if (Helper) { 2603 2604 // special printing for statement-expressions. 2605 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2606 CompoundStmt* Sub = SE->getSubStmt(); 2607 2608 if (Sub->child_begin() != Sub->child_end()) { 2609 OS << "({ ... ; "; 2610 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2611 OS << " })\n"; 2612 return; 2613 } 2614 } 2615 // special printing for comma expressions. 2616 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2617 if (B->getOpcode() == BO_Comma) { 2618 OS << "... , "; 2619 Helper->handledStmt(B->getRHS(),OS); 2620 OS << '\n'; 2621 return; 2622 } 2623 } 2624 } 2625 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2626 2627 if (isa<CXXOperatorCallExpr>(S)) { 2628 OS << " (OperatorCall)"; 2629 } 2630 else if (isa<CXXBindTemporaryExpr>(S)) { 2631 OS << " (BindTemporary)"; 2632 } 2633 2634 // Expressions need a newline. 2635 if (isa<Expr>(S)) 2636 OS << '\n'; 2637 2638 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2639 CXXBaseOrMemberInitializer* I = IE; 2640 if (I->isBaseInitializer()) 2641 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2642 else OS << I->getMember()->getName(); 2643 2644 OS << "("; 2645 if (Expr* IE = I->getInit()) 2646 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2647 OS << ")"; 2648 2649 if (I->isBaseInitializer()) 2650 OS << " (Base initializer)\n"; 2651 else OS << " (Member initializer)\n"; 2652 2653 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2654 VarDecl* VD = DE.getVarDecl(); 2655 Helper->handleDecl(VD, OS); 2656 2657 Type* T = VD->getType().getTypePtr(); 2658 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2659 T = RT->getPointeeType().getTypePtr(); 2660 2661 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2662 OS << " (Implicit destructor)\n"; 2663 } 2664 } 2665 2666static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2667 const CFGBlock& B, 2668 StmtPrinterHelper* Helper, bool print_edges) { 2669 2670 if (Helper) Helper->setBlockID(B.getBlockID()); 2671 2672 // Print the header. 2673 OS << "\n [ B" << B.getBlockID(); 2674 2675 if (&B == &cfg->getEntry()) 2676 OS << " (ENTRY) ]\n"; 2677 else if (&B == &cfg->getExit()) 2678 OS << " (EXIT) ]\n"; 2679 else if (&B == cfg->getIndirectGotoBlock()) 2680 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2681 else 2682 OS << " ]\n"; 2683 2684 // Print the label of this block. 2685 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2686 2687 if (print_edges) 2688 OS << " "; 2689 2690 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2691 OS << L->getName(); 2692 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2693 OS << "case "; 2694 C->getLHS()->printPretty(OS, Helper, 2695 PrintingPolicy(Helper->getLangOpts())); 2696 if (C->getRHS()) { 2697 OS << " ... "; 2698 C->getRHS()->printPretty(OS, Helper, 2699 PrintingPolicy(Helper->getLangOpts())); 2700 } 2701 } else if (isa<DefaultStmt>(Label)) 2702 OS << "default"; 2703 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2704 OS << "catch ("; 2705 if (CS->getExceptionDecl()) 2706 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2707 0); 2708 else 2709 OS << "..."; 2710 OS << ")"; 2711 2712 } else 2713 assert(false && "Invalid label statement in CFGBlock."); 2714 2715 OS << ":\n"; 2716 } 2717 2718 // Iterate through the statements in the block and print them. 2719 unsigned j = 1; 2720 2721 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2722 I != E ; ++I, ++j ) { 2723 2724 // Print the statement # in the basic block and the statement itself. 2725 if (print_edges) 2726 OS << " "; 2727 2728 OS << llvm::format("%3d", j) << ": "; 2729 2730 if (Helper) 2731 Helper->setStmtID(j); 2732 2733 print_elem(OS,Helper,*I); 2734 } 2735 2736 // Print the terminator of this block. 2737 if (B.getTerminator()) { 2738 if (print_edges) 2739 OS << " "; 2740 2741 OS << " T: "; 2742 2743 if (Helper) Helper->setBlockID(-1); 2744 2745 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2746 PrintingPolicy(Helper->getLangOpts())); 2747 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2748 OS << '\n'; 2749 } 2750 2751 if (print_edges) { 2752 // Print the predecessors of this block. 2753 OS << " Predecessors (" << B.pred_size() << "):"; 2754 unsigned i = 0; 2755 2756 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2757 I != E; ++I, ++i) { 2758 2759 if (i == 8 || (i-8) == 0) 2760 OS << "\n "; 2761 2762 OS << " B" << (*I)->getBlockID(); 2763 } 2764 2765 OS << '\n'; 2766 2767 // Print the successors of this block. 2768 OS << " Successors (" << B.succ_size() << "):"; 2769 i = 0; 2770 2771 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2772 I != E; ++I, ++i) { 2773 2774 if (i == 8 || (i-8) % 10 == 0) 2775 OS << "\n "; 2776 2777 if (*I) 2778 OS << " B" << (*I)->getBlockID(); 2779 else 2780 OS << " NULL"; 2781 } 2782 2783 OS << '\n'; 2784 } 2785} 2786 2787 2788/// dump - A simple pretty printer of a CFG that outputs to stderr. 2789void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2790 2791/// print - A simple pretty printer of a CFG that outputs to an ostream. 2792void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2793 StmtPrinterHelper Helper(this, LO); 2794 2795 // Print the entry block. 2796 print_block(OS, this, getEntry(), &Helper, true); 2797 2798 // Iterate through the CFGBlocks and print them one by one. 2799 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2800 // Skip the entry block, because we already printed it. 2801 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2802 continue; 2803 2804 print_block(OS, this, **I, &Helper, true); 2805 } 2806 2807 // Print the exit block. 2808 print_block(OS, this, getExit(), &Helper, true); 2809 OS.flush(); 2810} 2811 2812/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2813void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2814 print(llvm::errs(), cfg, LO); 2815} 2816 2817/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2818/// Generally this will only be called from CFG::print. 2819void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2820 const LangOptions &LO) const { 2821 StmtPrinterHelper Helper(cfg, LO); 2822 print_block(OS, cfg, *this, &Helper, true); 2823} 2824 2825/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2826void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2827 const LangOptions &LO) const { 2828 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2829 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2830} 2831 2832Stmt* CFGBlock::getTerminatorCondition() { 2833 2834 if (!Terminator) 2835 return NULL; 2836 2837 Expr* E = NULL; 2838 2839 switch (Terminator->getStmtClass()) { 2840 default: 2841 break; 2842 2843 case Stmt::ForStmtClass: 2844 E = cast<ForStmt>(Terminator)->getCond(); 2845 break; 2846 2847 case Stmt::WhileStmtClass: 2848 E = cast<WhileStmt>(Terminator)->getCond(); 2849 break; 2850 2851 case Stmt::DoStmtClass: 2852 E = cast<DoStmt>(Terminator)->getCond(); 2853 break; 2854 2855 case Stmt::IfStmtClass: 2856 E = cast<IfStmt>(Terminator)->getCond(); 2857 break; 2858 2859 case Stmt::ChooseExprClass: 2860 E = cast<ChooseExpr>(Terminator)->getCond(); 2861 break; 2862 2863 case Stmt::IndirectGotoStmtClass: 2864 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2865 break; 2866 2867 case Stmt::SwitchStmtClass: 2868 E = cast<SwitchStmt>(Terminator)->getCond(); 2869 break; 2870 2871 case Stmt::ConditionalOperatorClass: 2872 E = cast<ConditionalOperator>(Terminator)->getCond(); 2873 break; 2874 2875 case Stmt::BinaryOperatorClass: // '&&' and '||' 2876 E = cast<BinaryOperator>(Terminator)->getLHS(); 2877 break; 2878 2879 case Stmt::ObjCForCollectionStmtClass: 2880 return Terminator; 2881 } 2882 2883 return E ? E->IgnoreParens() : NULL; 2884} 2885 2886bool CFGBlock::hasBinaryBranchTerminator() const { 2887 2888 if (!Terminator) 2889 return false; 2890 2891 Expr* E = NULL; 2892 2893 switch (Terminator->getStmtClass()) { 2894 default: 2895 return false; 2896 2897 case Stmt::ForStmtClass: 2898 case Stmt::WhileStmtClass: 2899 case Stmt::DoStmtClass: 2900 case Stmt::IfStmtClass: 2901 case Stmt::ChooseExprClass: 2902 case Stmt::ConditionalOperatorClass: 2903 case Stmt::BinaryOperatorClass: 2904 return true; 2905 } 2906 2907 return E ? E->IgnoreParens() : NULL; 2908} 2909 2910 2911//===----------------------------------------------------------------------===// 2912// CFG Graphviz Visualization 2913//===----------------------------------------------------------------------===// 2914 2915 2916#ifndef NDEBUG 2917static StmtPrinterHelper* GraphHelper; 2918#endif 2919 2920void CFG::viewCFG(const LangOptions &LO) const { 2921#ifndef NDEBUG 2922 StmtPrinterHelper H(this, LO); 2923 GraphHelper = &H; 2924 llvm::ViewGraph(this,"CFG"); 2925 GraphHelper = NULL; 2926#endif 2927} 2928 2929namespace llvm { 2930template<> 2931struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2932 2933 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2934 2935 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 2936 2937#ifndef NDEBUG 2938 std::string OutSStr; 2939 llvm::raw_string_ostream Out(OutSStr); 2940 print_block(Out,Graph, *Node, GraphHelper, false); 2941 std::string& OutStr = Out.str(); 2942 2943 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2944 2945 // Process string output to make it nicer... 2946 for (unsigned i = 0; i != OutStr.length(); ++i) 2947 if (OutStr[i] == '\n') { // Left justify 2948 OutStr[i] = '\\'; 2949 OutStr.insert(OutStr.begin()+i+1, 'l'); 2950 } 2951 2952 return OutStr; 2953#else 2954 return ""; 2955#endif 2956 } 2957}; 2958} // end namespace llvm 2959