CFG.cpp revision 3f46279e9c4887ed72406e740830f0a58adcc38a
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39class AddStmtChoice { 40public: 41 enum Kind { NotAlwaysAdd = 0, 42 AlwaysAdd = 1, 43 AsLValueNotAlwaysAdd = 2, 44 AlwaysAddAsLValue = 3 }; 45 46 AddStmtChoice(Kind kind) : k(kind) {} 47 48 bool alwaysAdd() const { return (unsigned)k & 0x1; } 49 bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } 50 51private: 52 Kind k; 53}; 54 55/// LocalScope - Node in tree of local scopes created for C++ implicit 56/// destructor calls generation. It contains list of automatic variables 57/// declared in the scope and link to position in previous scope this scope 58/// began in. 59/// 60/// The process of creating local scopes is as follows: 61/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 62/// - Before processing statements in scope (e.g. CompoundStmt) create 63/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 64/// and set CFGBuilder::ScopePos to the end of new scope, 65/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 66/// at this VarDecl, 67/// - For every normal (without jump) end of scope add to CFGBlock destructors 68/// for objects in the current scope, 69/// - For every jump add to CFGBlock destructors for objects 70/// between CFGBuilder::ScopePos and local scope position saved for jump 71/// target. Thanks to C++ restrictions on goto jumps we can be sure that 72/// jump target position will be on the path to root from CFGBuilder::ScopePos 73/// (adding any variable that doesn't need constructor to be called to 74/// LocalScope can break this assumption), 75/// 76class LocalScope { 77public: 78 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 79 80 /// const_iterator - Iterates local scope backwards and jumps to previous 81 /// scope on reaching the beginning of currently iterated scope. 82 class const_iterator { 83 const LocalScope* Scope; 84 85 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 86 /// Invalid iterator (with null Scope) has VarIter equal to 0. 87 unsigned VarIter; 88 89 public: 90 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 91 /// Incrementing invalid iterator is allowed and will result in invalid 92 /// iterator. 93 const_iterator() 94 : Scope(NULL), VarIter(0) {} 95 96 /// Create valid iterator. In case when S.Prev is an invalid iterator and 97 /// I is equal to 0, this will create invalid iterator. 98 const_iterator(const LocalScope& S, unsigned I) 99 : Scope(&S), VarIter(I) { 100 // Iterator to "end" of scope is not allowed. Handle it by going up 101 // in scopes tree possibly up to invalid iterator in the root. 102 if (VarIter == 0 && Scope) 103 *this = Scope->Prev; 104 } 105 106 VarDecl* const* operator->() const { 107 assert (Scope && "Dereferencing invalid iterator is not allowed"); 108 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 109 return &Scope->Vars[VarIter - 1]; 110 } 111 VarDecl* operator*() const { 112 return *this->operator->(); 113 } 114 115 const_iterator& operator++() { 116 if (!Scope) 117 return *this; 118 119 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 120 --VarIter; 121 if (VarIter == 0) 122 *this = Scope->Prev; 123 return *this; 124 } 125 const_iterator operator++(int) { 126 const_iterator P = *this; 127 ++*this; 128 return P; 129 } 130 131 bool operator==(const const_iterator& rhs) const { 132 return Scope == rhs.Scope && VarIter == rhs.VarIter; 133 } 134 bool operator!=(const const_iterator& rhs) const { 135 return !(*this == rhs); 136 } 137 138 operator bool() const { 139 return *this != const_iterator(); 140 } 141 142 int distance(const_iterator L); 143 }; 144 145 friend class const_iterator; 146 147private: 148 /// Automatic variables in order of declaration. 149 AutomaticVarsTy Vars; 150 /// Iterator to variable in previous scope that was declared just before 151 /// begin of this scope. 152 const_iterator Prev; 153 154public: 155 /// Constructs empty scope linked to previous scope in specified place. 156 LocalScope(const_iterator P) 157 : Vars() 158 , Prev(P) {} 159 160 /// Begin of scope in direction of CFG building (backwards). 161 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 162 163 void addVar(VarDecl* VD) { 164 Vars.push_back(VD); 165 } 166}; 167 168/// distance - Calculates distance from this to L. L must be reachable from this 169/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 170/// number of scopes between this and L. 171int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 172 int D = 0; 173 const_iterator F = *this; 174 while (F.Scope != L.Scope) { 175 assert (F != const_iterator() 176 && "L iterator is not reachable from F iterator."); 177 D += F.VarIter; 178 F = F.Scope->Prev; 179 } 180 D += F.VarIter - L.VarIter; 181 return D; 182} 183 184/// BlockScopePosPair - Structure for specifying position in CFG during its 185/// build process. It consists of CFGBlock that specifies position in CFG graph 186/// and LocalScope::const_iterator that specifies position in LocalScope graph. 187struct BlockScopePosPair { 188 BlockScopePosPair() {} 189 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 190 : Block(B), ScopePos(S) {} 191 192 CFGBlock* Block; 193 LocalScope::const_iterator ScopePos; 194}; 195 196/// CFGBuilder - This class implements CFG construction from an AST. 197/// The builder is stateful: an instance of the builder should be used to only 198/// construct a single CFG. 199/// 200/// Example usage: 201/// 202/// CFGBuilder builder; 203/// CFG* cfg = builder.BuildAST(stmt1); 204/// 205/// CFG construction is done via a recursive walk of an AST. We actually parse 206/// the AST in reverse order so that the successor of a basic block is 207/// constructed prior to its predecessor. This allows us to nicely capture 208/// implicit fall-throughs without extra basic blocks. 209/// 210class CFGBuilder { 211 typedef BlockScopePosPair JumpTarget; 212 typedef BlockScopePosPair JumpSource; 213 214 ASTContext *Context; 215 llvm::OwningPtr<CFG> cfg; 216 217 CFGBlock* Block; 218 CFGBlock* Succ; 219 JumpTarget ContinueJumpTarget; 220 JumpTarget BreakJumpTarget; 221 CFGBlock* SwitchTerminatedBlock; 222 CFGBlock* DefaultCaseBlock; 223 CFGBlock* TryTerminatedBlock; 224 225 // Current position in local scope. 226 LocalScope::const_iterator ScopePos; 227 228 // LabelMap records the mapping from Label expressions to their jump targets. 229 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 230 LabelMapTy LabelMap; 231 232 // A list of blocks that end with a "goto" that must be backpatched to their 233 // resolved targets upon completion of CFG construction. 234 typedef std::vector<JumpSource> BackpatchBlocksTy; 235 BackpatchBlocksTy BackpatchBlocks; 236 237 // A list of labels whose address has been taken (for indirect gotos). 238 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 239 LabelSetTy AddressTakenLabels; 240 241 bool badCFG; 242 CFG::BuildOptions BuildOpts; 243 244public: 245 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 246 Block(NULL), Succ(NULL), 247 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 248 TryTerminatedBlock(NULL), badCFG(false) {} 249 250 // buildCFG - Used by external clients to construct the CFG. 251 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 252 CFG::BuildOptions BO); 253 254private: 255 // Visitors to walk an AST and construct the CFG. 256 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 257 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 258 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 259 CFGBlock *VisitBreakStmt(BreakStmt *B); 260 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 261 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 262 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 263 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 264 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 265 CFGBlock *VisitCaseStmt(CaseStmt *C); 266 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 267 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 268 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 269 CFGBlock *VisitContinueStmt(ContinueStmt *C); 270 CFGBlock *VisitDeclStmt(DeclStmt *DS); 271 CFGBlock *VisitDeclSubExpr(Decl* D); 272 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 273 CFGBlock *VisitDoStmt(DoStmt *D); 274 CFGBlock *VisitForStmt(ForStmt *F); 275 CFGBlock *VisitGotoStmt(GotoStmt* G); 276 CFGBlock *VisitIfStmt(IfStmt *I); 277 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 278 CFGBlock *VisitLabelStmt(LabelStmt *L); 279 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 280 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 281 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 282 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 283 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 284 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 285 CFGBlock *VisitReturnStmt(ReturnStmt* R); 286 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 287 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 288 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 289 CFGBlock *VisitWhileStmt(WhileStmt *W); 290 291 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 292 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 293 CFGBlock *VisitChildren(Stmt* S); 294 295 // NYS == Not Yet Supported 296 CFGBlock* NYS() { 297 badCFG = true; 298 return Block; 299 } 300 301 void autoCreateBlock() { if (!Block) Block = createBlock(); } 302 CFGBlock *createBlock(bool add_successor = true); 303 304 CFGBlock *addStmt(Stmt *S) { 305 return Visit(S, AddStmtChoice::AlwaysAdd); 306 } 307 CFGBlock *addInitializer(CXXBaseOrMemberInitializer *I); 308 void addAutomaticObjDtors(LocalScope::const_iterator B, 309 LocalScope::const_iterator E, Stmt* S); 310 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 311 312 // Local scopes creation. 313 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 314 315 void addLocalScopeForStmt(Stmt* S); 316 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 317 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 318 319 void addLocalScopeAndDtors(Stmt* S); 320 321 // Interface to CFGBlock - adding CFGElements. 322 void AppendStmt(CFGBlock *B, Stmt *S, 323 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 324 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 325 } 326 void appendInitializer(CFGBlock *B, CXXBaseOrMemberInitializer *I) { 327 B->appendInitializer(I, cfg->getBumpVectorContext()); 328 } 329 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 330 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 331 } 332 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 333 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 334 } 335 336 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 337 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 338 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 339 LocalScope::const_iterator E, Stmt* S); 340 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 341 LocalScope::const_iterator B, LocalScope::const_iterator E); 342 343 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 344 B->addSuccessor(S, cfg->getBumpVectorContext()); 345 } 346 347 /// TryResult - a class representing a variant over the values 348 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 349 /// and is used by the CFGBuilder to decide if a branch condition 350 /// can be decided up front during CFG construction. 351 class TryResult { 352 int X; 353 public: 354 TryResult(bool b) : X(b ? 1 : 0) {} 355 TryResult() : X(-1) {} 356 357 bool isTrue() const { return X == 1; } 358 bool isFalse() const { return X == 0; } 359 bool isKnown() const { return X >= 0; } 360 void negate() { 361 assert(isKnown()); 362 X ^= 0x1; 363 } 364 }; 365 366 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 367 /// if we can evaluate to a known value, otherwise return -1. 368 TryResult TryEvaluateBool(Expr *S) { 369 if (!BuildOpts.PruneTriviallyFalseEdges) 370 return TryResult(); 371 372 Expr::EvalResult Result; 373 if (!S->isTypeDependent() && !S->isValueDependent() && 374 S->Evaluate(Result, *Context) && Result.Val.isInt()) 375 return Result.Val.getInt().getBoolValue(); 376 377 return TryResult(); 378 } 379}; 380 381// FIXME: Add support for dependent-sized array types in C++? 382// Does it even make sense to build a CFG for an uninstantiated template? 383static VariableArrayType* FindVA(Type* t) { 384 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 385 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 386 if (vat->getSizeExpr()) 387 return vat; 388 389 t = vt->getElementType().getTypePtr(); 390 } 391 392 return 0; 393} 394 395/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 396/// arbitrary statement. Examples include a single expression or a function 397/// body (compound statement). The ownership of the returned CFG is 398/// transferred to the caller. If CFG construction fails, this method returns 399/// NULL. 400CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 401 CFG::BuildOptions BO) { 402 403 Context = C; 404 assert(cfg.get()); 405 if (!Statement) 406 return NULL; 407 408 BuildOpts = BO; 409 410 // Create an empty block that will serve as the exit block for the CFG. Since 411 // this is the first block added to the CFG, it will be implicitly registered 412 // as the exit block. 413 Succ = createBlock(); 414 assert(Succ == &cfg->getExit()); 415 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 416 417 if (BuildOpts.AddImplicitDtors) 418 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 419 addImplicitDtorsForDestructor(DD); 420 421 // Visit the statements and create the CFG. 422 CFGBlock *B = addStmt(Statement); 423 424 if (badCFG) 425 return NULL; 426 427 // For C++ constructor add initializers to CFG. 428 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 429 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 430 E = CD->init_rend(); I != E; ++I) { 431 B = addInitializer(*I); 432 if (badCFG) 433 return NULL; 434 } 435 } 436 437 if (B) 438 Succ = B; 439 440 // Backpatch the gotos whose label -> block mappings we didn't know when we 441 // encountered them. 442 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 443 E = BackpatchBlocks.end(); I != E; ++I ) { 444 445 CFGBlock* B = I->Block; 446 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 447 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 448 449 // If there is no target for the goto, then we are looking at an 450 // incomplete AST. Handle this by not registering a successor. 451 if (LI == LabelMap.end()) continue; 452 453 JumpTarget JT = LI->second; 454 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 455 AddSuccessor(B, JT.Block); 456 } 457 458 // Add successors to the Indirect Goto Dispatch block (if we have one). 459 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 460 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 461 E = AddressTakenLabels.end(); I != E; ++I ) { 462 463 // Lookup the target block. 464 LabelMapTy::iterator LI = LabelMap.find(*I); 465 466 // If there is no target block that contains label, then we are looking 467 // at an incomplete AST. Handle this by not registering a successor. 468 if (LI == LabelMap.end()) continue; 469 470 AddSuccessor(B, LI->second.Block); 471 } 472 473 // Create an empty entry block that has no predecessors. 474 cfg->setEntry(createBlock()); 475 476 return cfg.take(); 477} 478 479/// createBlock - Used to lazily create blocks that are connected 480/// to the current (global) succcessor. 481CFGBlock* CFGBuilder::createBlock(bool add_successor) { 482 CFGBlock* B = cfg->createBlock(); 483 if (add_successor && Succ) 484 AddSuccessor(B, Succ); 485 return B; 486} 487 488/// addInitializer - Add C++ base or member initializer element to CFG. 489CFGBlock *CFGBuilder::addInitializer(CXXBaseOrMemberInitializer *I) { 490 if (!BuildOpts.AddInitializers) 491 return Block; 492 493 autoCreateBlock(); 494 appendInitializer(Block, I); 495 496 if (Expr *Init = I->getInit()) { 497 AddStmtChoice::Kind K = AddStmtChoice::NotAlwaysAdd; 498 if (FieldDecl *FD = I->getMember()) 499 if (FD->getType()->isReferenceType()) 500 K = AddStmtChoice::AsLValueNotAlwaysAdd; 501 502 return Visit(Init, AddStmtChoice(K)); 503 } 504 505 return Block; 506} 507 508/// addAutomaticObjDtors - Add to current block automatic objects destructors 509/// for objects in range of local scope positions. Use S as trigger statement 510/// for destructors. 511void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 512 LocalScope::const_iterator E, Stmt* S) { 513 if (!BuildOpts.AddImplicitDtors) 514 return; 515 516 if (B == E) 517 return; 518 519 autoCreateBlock(); 520 appendAutomaticObjDtors(Block, B, E, S); 521} 522 523/// addImplicitDtorsForDestructor - Add implicit destructors generated for 524/// base and member objects in destructor. 525void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 526 assert (BuildOpts.AddImplicitDtors 527 && "Can be called only when dtors should be added"); 528 const CXXRecordDecl *RD = DD->getParent(); 529 530 // At the end destroy virtual base objects. 531 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 532 VE = RD->vbases_end(); VI != VE; ++VI) { 533 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 534 if (!CD->hasTrivialDestructor()) { 535 autoCreateBlock(); 536 appendBaseDtor(Block, VI); 537 } 538 } 539 540 // Before virtual bases destroy direct base objects. 541 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 542 BE = RD->bases_end(); BI != BE; ++BI) { 543 if (!BI->isVirtual()) { 544 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 545 if (!CD->hasTrivialDestructor()) { 546 autoCreateBlock(); 547 appendBaseDtor(Block, BI); 548 } 549 } 550 } 551 552 // First destroy member objects. 553 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 554 FE = RD->field_end(); FI != FE; ++FI) { 555 if (const CXXRecordDecl *CD = FI->getType()->getAsCXXRecordDecl()) 556 if (!CD->hasTrivialDestructor()) { 557 autoCreateBlock(); 558 appendMemberDtor(Block, *FI); 559 } 560 } 561} 562 563/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 564/// way return valid LocalScope object. 565LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 566 if (!Scope) { 567 Scope = cfg->getAllocator().Allocate<LocalScope>(); 568 new (Scope) LocalScope(ScopePos); 569 } 570 return Scope; 571} 572 573/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 574/// that should create implicit scope (e.g. if/else substatements). 575void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 576 if (!BuildOpts.AddImplicitDtors) 577 return; 578 579 LocalScope *Scope = 0; 580 581 // For compound statement we will be creating explicit scope. 582 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 583 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 584 ; BI != BE; ++BI) { 585 Stmt* SI = *BI; 586 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 587 SI = LS->getSubStmt(); 588 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 589 Scope = addLocalScopeForDeclStmt(DS, Scope); 590 } 591 return; 592 } 593 594 // For any other statement scope will be implicit and as such will be 595 // interesting only for DeclStmt. 596 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 597 S = LS->getSubStmt(); 598 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 599 addLocalScopeForDeclStmt(DS); 600} 601 602/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 603/// reuse Scope if not NULL. 604LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 605 LocalScope* Scope) { 606 if (!BuildOpts.AddImplicitDtors) 607 return Scope; 608 609 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 610 ; DI != DE; ++DI) { 611 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 612 Scope = addLocalScopeForVarDecl(VD, Scope); 613 } 614 return Scope; 615} 616 617/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 618/// create add scope for automatic objects and temporary objects bound to 619/// const reference. Will reuse Scope if not NULL. 620LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 621 LocalScope* Scope) { 622 if (!BuildOpts.AddImplicitDtors) 623 return Scope; 624 625 // Check if variable is local. 626 switch (VD->getStorageClass()) { 627 case SC_None: 628 case SC_Auto: 629 case SC_Register: 630 break; 631 default: return Scope; 632 } 633 634 // Check for const references bound to temporary. Set type to pointee. 635 QualType QT = VD->getType(); 636 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 637 QT = RT->getPointeeType(); 638 if (!QT.isConstQualified()) 639 return Scope; 640 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 641 return Scope; 642 } 643 644 // Check for constant size array. Set type to array element type. 645 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 646 if (AT->getSize() == 0) 647 return Scope; 648 QT = AT->getElementType(); 649 } 650 651 // Check if type is a C++ class with non-trivial destructor. 652 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 653 if (!CD->hasTrivialDestructor()) { 654 // Add the variable to scope 655 Scope = createOrReuseLocalScope(Scope); 656 Scope->addVar(VD); 657 ScopePos = Scope->begin(); 658 } 659 return Scope; 660} 661 662/// addLocalScopeAndDtors - For given statement add local scope for it and 663/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 664void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 665 if (!BuildOpts.AddImplicitDtors) 666 return; 667 668 LocalScope::const_iterator scopeBeginPos = ScopePos; 669 addLocalScopeForStmt(S); 670 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 671} 672 673/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 674/// automatic storage duration to CFGBlock's elements vector. Insertion will be 675/// performed in place specified with iterator. 676void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 677 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 678 BumpVectorContext& C = cfg->getBumpVectorContext(); 679 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 680 while (B != E) 681 I = Blk->insertAutomaticObjDtor(I, *B++, S); 682} 683 684/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 685/// automatic storage duration to CFGBlock's elements vector. Elements will be 686/// appended to physical end of the vector which happens to be logical 687/// beginning. 688void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 689 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 690 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 691} 692 693/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 694/// variables with automatic storage duration to CFGBlock's elements vector. 695/// Elements will be prepended to physical beginning of the vector which 696/// happens to be logical end. Use blocks terminator as statement that specifies 697/// destructors call site. 698void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 699 LocalScope::const_iterator B, LocalScope::const_iterator E) { 700 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 701} 702 703/// Visit - Walk the subtree of a statement and add extra 704/// blocks for ternary operators, &&, and ||. We also process "," and 705/// DeclStmts (which may contain nested control-flow). 706CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 707tryAgain: 708 if (!S) { 709 badCFG = true; 710 return 0; 711 } 712 switch (S->getStmtClass()) { 713 default: 714 return VisitStmt(S, asc); 715 716 case Stmt::AddrLabelExprClass: 717 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 718 719 case Stmt::BinaryOperatorClass: 720 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 721 722 case Stmt::BlockExprClass: 723 return VisitBlockExpr(cast<BlockExpr>(S), asc); 724 725 case Stmt::BreakStmtClass: 726 return VisitBreakStmt(cast<BreakStmt>(S)); 727 728 case Stmt::CallExprClass: 729 case Stmt::CXXOperatorCallExprClass: 730 return VisitCallExpr(cast<CallExpr>(S), asc); 731 732 case Stmt::CaseStmtClass: 733 return VisitCaseStmt(cast<CaseStmt>(S)); 734 735 case Stmt::ChooseExprClass: 736 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 737 738 case Stmt::CompoundStmtClass: 739 return VisitCompoundStmt(cast<CompoundStmt>(S)); 740 741 case Stmt::ConditionalOperatorClass: 742 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 743 744 case Stmt::ContinueStmtClass: 745 return VisitContinueStmt(cast<ContinueStmt>(S)); 746 747 case Stmt::CXXCatchStmtClass: 748 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 749 750 case Stmt::CXXExprWithTemporariesClass: { 751 // FIXME: Handle temporaries. For now, just visit the subexpression 752 // so we don't artificially create extra blocks. 753 return Visit(cast<CXXExprWithTemporaries>(S)->getSubExpr(), asc); 754 } 755 756 case Stmt::CXXMemberCallExprClass: 757 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 758 759 case Stmt::CXXThrowExprClass: 760 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 761 762 case Stmt::CXXTryStmtClass: 763 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 764 765 case Stmt::DeclStmtClass: 766 return VisitDeclStmt(cast<DeclStmt>(S)); 767 768 case Stmt::DefaultStmtClass: 769 return VisitDefaultStmt(cast<DefaultStmt>(S)); 770 771 case Stmt::DoStmtClass: 772 return VisitDoStmt(cast<DoStmt>(S)); 773 774 case Stmt::ForStmtClass: 775 return VisitForStmt(cast<ForStmt>(S)); 776 777 case Stmt::GotoStmtClass: 778 return VisitGotoStmt(cast<GotoStmt>(S)); 779 780 case Stmt::IfStmtClass: 781 return VisitIfStmt(cast<IfStmt>(S)); 782 783 case Stmt::IndirectGotoStmtClass: 784 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 785 786 case Stmt::LabelStmtClass: 787 return VisitLabelStmt(cast<LabelStmt>(S)); 788 789 case Stmt::MemberExprClass: 790 return VisitMemberExpr(cast<MemberExpr>(S), asc); 791 792 case Stmt::ObjCAtCatchStmtClass: 793 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 794 795 case Stmt::ObjCAtSynchronizedStmtClass: 796 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 797 798 case Stmt::ObjCAtThrowStmtClass: 799 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 800 801 case Stmt::ObjCAtTryStmtClass: 802 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 803 804 case Stmt::ObjCForCollectionStmtClass: 805 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 806 807 case Stmt::ParenExprClass: 808 S = cast<ParenExpr>(S)->getSubExpr(); 809 goto tryAgain; 810 811 case Stmt::NullStmtClass: 812 return Block; 813 814 case Stmt::ReturnStmtClass: 815 return VisitReturnStmt(cast<ReturnStmt>(S)); 816 817 case Stmt::SizeOfAlignOfExprClass: 818 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 819 820 case Stmt::StmtExprClass: 821 return VisitStmtExpr(cast<StmtExpr>(S), asc); 822 823 case Stmt::SwitchStmtClass: 824 return VisitSwitchStmt(cast<SwitchStmt>(S)); 825 826 case Stmt::WhileStmtClass: 827 return VisitWhileStmt(cast<WhileStmt>(S)); 828 } 829} 830 831CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 832 if (asc.alwaysAdd()) { 833 autoCreateBlock(); 834 AppendStmt(Block, S, asc); 835 } 836 837 return VisitChildren(S); 838} 839 840/// VisitChildren - Visit the children of a Stmt. 841CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 842 CFGBlock *B = Block; 843 for (Stmt::child_iterator I = Terminator->child_begin(), 844 E = Terminator->child_end(); I != E; ++I) { 845 if (*I) B = Visit(*I); 846 } 847 return B; 848} 849 850CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 851 AddStmtChoice asc) { 852 AddressTakenLabels.insert(A->getLabel()); 853 854 if (asc.alwaysAdd()) { 855 autoCreateBlock(); 856 AppendStmt(Block, A, asc); 857 } 858 859 return Block; 860} 861 862CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 863 AddStmtChoice asc) { 864 if (B->isLogicalOp()) { // && or || 865 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 866 AppendStmt(ConfluenceBlock, B, asc); 867 868 if (badCFG) 869 return 0; 870 871 // create the block evaluating the LHS 872 CFGBlock* LHSBlock = createBlock(false); 873 LHSBlock->setTerminator(B); 874 875 // create the block evaluating the RHS 876 Succ = ConfluenceBlock; 877 Block = NULL; 878 CFGBlock* RHSBlock = addStmt(B->getRHS()); 879 880 if (RHSBlock) { 881 if (badCFG) 882 return 0; 883 } 884 else { 885 // Create an empty block for cases where the RHS doesn't require 886 // any explicit statements in the CFG. 887 RHSBlock = createBlock(); 888 } 889 890 // See if this is a known constant. 891 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 892 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 893 KnownVal.negate(); 894 895 // Now link the LHSBlock with RHSBlock. 896 if (B->getOpcode() == BO_LOr) { 897 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 898 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 899 } else { 900 assert(B->getOpcode() == BO_LAnd); 901 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 902 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 903 } 904 905 // Generate the blocks for evaluating the LHS. 906 Block = LHSBlock; 907 return addStmt(B->getLHS()); 908 } 909 else if (B->getOpcode() == BO_Comma) { // , 910 autoCreateBlock(); 911 AppendStmt(Block, B, asc); 912 addStmt(B->getRHS()); 913 return addStmt(B->getLHS()); 914 } 915 else if (B->isAssignmentOp()) { 916 if (asc.alwaysAdd()) { 917 autoCreateBlock(); 918 AppendStmt(Block, B, asc); 919 } 920 921 Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 922 return Visit(B->getRHS()); 923 } 924 925 if (asc.alwaysAdd()) { 926 autoCreateBlock(); 927 AppendStmt(Block, B, asc); 928 } 929 930 Visit(B->getRHS()); 931 return Visit(B->getLHS()); 932} 933 934CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 935 if (asc.alwaysAdd()) { 936 autoCreateBlock(); 937 AppendStmt(Block, E, asc); 938 } 939 return Block; 940} 941 942CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 943 // "break" is a control-flow statement. Thus we stop processing the current 944 // block. 945 if (badCFG) 946 return 0; 947 948 // Now create a new block that ends with the break statement. 949 Block = createBlock(false); 950 Block->setTerminator(B); 951 952 // If there is no target for the break, then we are looking at an incomplete 953 // AST. This means that the CFG cannot be constructed. 954 if (BreakJumpTarget.Block) { 955 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 956 AddSuccessor(Block, BreakJumpTarget.Block); 957 } else 958 badCFG = true; 959 960 961 return Block; 962} 963 964static bool CanThrow(Expr *E) { 965 QualType Ty = E->getType(); 966 if (Ty->isFunctionPointerType()) 967 Ty = Ty->getAs<PointerType>()->getPointeeType(); 968 else if (Ty->isBlockPointerType()) 969 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 970 971 const FunctionType *FT = Ty->getAs<FunctionType>(); 972 if (FT) { 973 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 974 if (Proto->hasEmptyExceptionSpec()) 975 return false; 976 } 977 return true; 978} 979 980CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 981 // If this is a call to a no-return function, this stops the block here. 982 bool NoReturn = false; 983 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 984 NoReturn = true; 985 } 986 987 bool AddEHEdge = false; 988 989 // Languages without exceptions are assumed to not throw. 990 if (Context->getLangOptions().Exceptions) { 991 if (BuildOpts.AddEHEdges) 992 AddEHEdge = true; 993 } 994 995 if (FunctionDecl *FD = C->getDirectCallee()) { 996 if (FD->hasAttr<NoReturnAttr>()) 997 NoReturn = true; 998 if (FD->hasAttr<NoThrowAttr>()) 999 AddEHEdge = false; 1000 } 1001 1002 if (!CanThrow(C->getCallee())) 1003 AddEHEdge = false; 1004 1005 if (!NoReturn && !AddEHEdge) { 1006 if (asc.asLValue()) 1007 return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue); 1008 else 1009 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 1010 } 1011 1012 if (Block) { 1013 Succ = Block; 1014 if (badCFG) 1015 return 0; 1016 } 1017 1018 Block = createBlock(!NoReturn); 1019 AppendStmt(Block, C, asc); 1020 1021 if (NoReturn) { 1022 // Wire this to the exit block directly. 1023 AddSuccessor(Block, &cfg->getExit()); 1024 } 1025 if (AddEHEdge) { 1026 // Add exceptional edges. 1027 if (TryTerminatedBlock) 1028 AddSuccessor(Block, TryTerminatedBlock); 1029 else 1030 AddSuccessor(Block, &cfg->getExit()); 1031 } 1032 1033 return VisitChildren(C); 1034} 1035 1036CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1037 AddStmtChoice asc) { 1038 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1039 AppendStmt(ConfluenceBlock, C, asc); 1040 if (badCFG) 1041 return 0; 1042 1043 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1044 : AddStmtChoice::AlwaysAdd; 1045 1046 Succ = ConfluenceBlock; 1047 Block = NULL; 1048 CFGBlock* LHSBlock = Visit(C->getLHS(), asc); 1049 if (badCFG) 1050 return 0; 1051 1052 Succ = ConfluenceBlock; 1053 Block = NULL; 1054 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1055 if (badCFG) 1056 return 0; 1057 1058 Block = createBlock(false); 1059 // See if this is a known constant. 1060 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1061 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1062 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1063 Block->setTerminator(C); 1064 return addStmt(C->getCond()); 1065} 1066 1067 1068CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1069 addLocalScopeAndDtors(C); 1070 CFGBlock* LastBlock = Block; 1071 1072 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1073 I != E; ++I ) { 1074 // If we hit a segment of code just containing ';' (NullStmts), we can 1075 // get a null block back. In such cases, just use the LastBlock 1076 if (CFGBlock *newBlock = addStmt(*I)) 1077 LastBlock = newBlock; 1078 1079 if (badCFG) 1080 return NULL; 1081 } 1082 1083 return LastBlock; 1084} 1085 1086CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1087 AddStmtChoice asc) { 1088 // Create the confluence block that will "merge" the results of the ternary 1089 // expression. 1090 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1091 AppendStmt(ConfluenceBlock, C, asc); 1092 if (badCFG) 1093 return 0; 1094 1095 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1096 : AddStmtChoice::AlwaysAdd; 1097 1098 // Create a block for the LHS expression if there is an LHS expression. A 1099 // GCC extension allows LHS to be NULL, causing the condition to be the 1100 // value that is returned instead. 1101 // e.g: x ?: y is shorthand for: x ? x : y; 1102 Succ = ConfluenceBlock; 1103 Block = NULL; 1104 CFGBlock* LHSBlock = NULL; 1105 if (C->getLHS()) { 1106 LHSBlock = Visit(C->getLHS(), asc); 1107 if (badCFG) 1108 return 0; 1109 Block = NULL; 1110 } 1111 1112 // Create the block for the RHS expression. 1113 Succ = ConfluenceBlock; 1114 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1115 if (badCFG) 1116 return 0; 1117 1118 // Create the block that will contain the condition. 1119 Block = createBlock(false); 1120 1121 // See if this is a known constant. 1122 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1123 if (LHSBlock) { 1124 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1125 } else { 1126 if (KnownVal.isFalse()) { 1127 // If we know the condition is false, add NULL as the successor for 1128 // the block containing the condition. In this case, the confluence 1129 // block will have just one predecessor. 1130 AddSuccessor(Block, 0); 1131 assert(ConfluenceBlock->pred_size() == 1); 1132 } else { 1133 // If we have no LHS expression, add the ConfluenceBlock as a direct 1134 // successor for the block containing the condition. Moreover, we need to 1135 // reverse the order of the predecessors in the ConfluenceBlock because 1136 // the RHSBlock will have been added to the succcessors already, and we 1137 // want the first predecessor to the the block containing the expression 1138 // for the case when the ternary expression evaluates to true. 1139 AddSuccessor(Block, ConfluenceBlock); 1140 assert(ConfluenceBlock->pred_size() == 2); 1141 std::reverse(ConfluenceBlock->pred_begin(), 1142 ConfluenceBlock->pred_end()); 1143 } 1144 } 1145 1146 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1147 Block->setTerminator(C); 1148 return addStmt(C->getCond()); 1149} 1150 1151CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1152 autoCreateBlock(); 1153 1154 if (DS->isSingleDecl()) { 1155 AppendStmt(Block, DS); 1156 return VisitDeclSubExpr(DS->getSingleDecl()); 1157 } 1158 1159 CFGBlock *B = 0; 1160 1161 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1162 typedef llvm::SmallVector<Decl*,10> BufTy; 1163 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1164 1165 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1166 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1167 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1168 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1169 1170 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1171 // automatically freed with the CFG. 1172 DeclGroupRef DG(*I); 1173 Decl *D = *I; 1174 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1175 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1176 1177 // Append the fake DeclStmt to block. 1178 AppendStmt(Block, DSNew); 1179 B = VisitDeclSubExpr(D); 1180 } 1181 1182 return B; 1183} 1184 1185/// VisitDeclSubExpr - Utility method to add block-level expressions for 1186/// initializers in Decls. 1187CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 1188 assert(Block); 1189 1190 VarDecl *VD = dyn_cast<VarDecl>(D); 1191 1192 if (!VD) 1193 return Block; 1194 1195 Expr *Init = VD->getInit(); 1196 1197 if (Init) { 1198 AddStmtChoice::Kind k = 1199 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 1200 : AddStmtChoice::NotAlwaysAdd; 1201 Visit(Init, AddStmtChoice(k)); 1202 } 1203 1204 // If the type of VD is a VLA, then we must process its size expressions. 1205 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1206 VA = FindVA(VA->getElementType().getTypePtr())) 1207 Block = addStmt(VA->getSizeExpr()); 1208 1209 // Remove variable from local scope. 1210 if (ScopePos && VD == *ScopePos) 1211 ++ScopePos; 1212 1213 return Block; 1214} 1215 1216CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1217 // We may see an if statement in the middle of a basic block, or it may be the 1218 // first statement we are processing. In either case, we create a new basic 1219 // block. First, we create the blocks for the then...else statements, and 1220 // then we create the block containing the if statement. If we were in the 1221 // middle of a block, we stop processing that block. That block is then the 1222 // implicit successor for the "then" and "else" clauses. 1223 1224 // Save local scope position because in case of condition variable ScopePos 1225 // won't be restored when traversing AST. 1226 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1227 1228 // Create local scope for possible condition variable. 1229 // Store scope position. Add implicit destructor. 1230 if (VarDecl* VD = I->getConditionVariable()) { 1231 LocalScope::const_iterator BeginScopePos = ScopePos; 1232 addLocalScopeForVarDecl(VD); 1233 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1234 } 1235 1236 // The block we were proccessing is now finished. Make it the successor 1237 // block. 1238 if (Block) { 1239 Succ = Block; 1240 if (badCFG) 1241 return 0; 1242 } 1243 1244 // Process the false branch. 1245 CFGBlock* ElseBlock = Succ; 1246 1247 if (Stmt* Else = I->getElse()) { 1248 SaveAndRestore<CFGBlock*> sv(Succ); 1249 1250 // NULL out Block so that the recursive call to Visit will 1251 // create a new basic block. 1252 Block = NULL; 1253 1254 // If branch is not a compound statement create implicit scope 1255 // and add destructors. 1256 if (!isa<CompoundStmt>(Else)) 1257 addLocalScopeAndDtors(Else); 1258 1259 ElseBlock = addStmt(Else); 1260 1261 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1262 ElseBlock = sv.get(); 1263 else if (Block) { 1264 if (badCFG) 1265 return 0; 1266 } 1267 } 1268 1269 // Process the true branch. 1270 CFGBlock* ThenBlock; 1271 { 1272 Stmt* Then = I->getThen(); 1273 assert(Then); 1274 SaveAndRestore<CFGBlock*> sv(Succ); 1275 Block = NULL; 1276 1277 // If branch is not a compound statement create implicit scope 1278 // and add destructors. 1279 if (!isa<CompoundStmt>(Then)) 1280 addLocalScopeAndDtors(Then); 1281 1282 ThenBlock = addStmt(Then); 1283 1284 if (!ThenBlock) { 1285 // We can reach here if the "then" body has all NullStmts. 1286 // Create an empty block so we can distinguish between true and false 1287 // branches in path-sensitive analyses. 1288 ThenBlock = createBlock(false); 1289 AddSuccessor(ThenBlock, sv.get()); 1290 } else if (Block) { 1291 if (badCFG) 1292 return 0; 1293 } 1294 } 1295 1296 // Now create a new block containing the if statement. 1297 Block = createBlock(false); 1298 1299 // Set the terminator of the new block to the If statement. 1300 Block->setTerminator(I); 1301 1302 // See if this is a known constant. 1303 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1304 1305 // Now add the successors. 1306 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1307 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1308 1309 // Add the condition as the last statement in the new block. This may create 1310 // new blocks as the condition may contain control-flow. Any newly created 1311 // blocks will be pointed to be "Block". 1312 Block = addStmt(I->getCond()); 1313 1314 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1315 // and the condition variable initialization to the CFG. 1316 if (VarDecl *VD = I->getConditionVariable()) { 1317 if (Expr *Init = VD->getInit()) { 1318 autoCreateBlock(); 1319 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1320 addStmt(Init); 1321 } 1322 } 1323 1324 return Block; 1325} 1326 1327 1328CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1329 // If we were in the middle of a block we stop processing that block. 1330 // 1331 // NOTE: If a "return" appears in the middle of a block, this means that the 1332 // code afterwards is DEAD (unreachable). We still keep a basic block 1333 // for that code; a simple "mark-and-sweep" from the entry block will be 1334 // able to report such dead blocks. 1335 1336 // Create the new block. 1337 Block = createBlock(false); 1338 1339 // The Exit block is the only successor. 1340 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1341 AddSuccessor(Block, &cfg->getExit()); 1342 1343 // Add the return statement to the block. This may create new blocks if R 1344 // contains control-flow (short-circuit operations). 1345 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1346} 1347 1348CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1349 // Get the block of the labeled statement. Add it to our map. 1350 addStmt(L->getSubStmt()); 1351 CFGBlock* LabelBlock = Block; 1352 1353 if (!LabelBlock) // This can happen when the body is empty, i.e. 1354 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1355 1356 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1357 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1358 1359 // Labels partition blocks, so this is the end of the basic block we were 1360 // processing (L is the block's label). Because this is label (and we have 1361 // already processed the substatement) there is no extra control-flow to worry 1362 // about. 1363 LabelBlock->setLabel(L); 1364 if (badCFG) 1365 return 0; 1366 1367 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1368 Block = NULL; 1369 1370 // This block is now the implicit successor of other blocks. 1371 Succ = LabelBlock; 1372 1373 return LabelBlock; 1374} 1375 1376CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1377 // Goto is a control-flow statement. Thus we stop processing the current 1378 // block and create a new one. 1379 1380 Block = createBlock(false); 1381 Block->setTerminator(G); 1382 1383 // If we already know the mapping to the label block add the successor now. 1384 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1385 1386 if (I == LabelMap.end()) 1387 // We will need to backpatch this block later. 1388 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1389 else { 1390 JumpTarget JT = I->second; 1391 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1392 AddSuccessor(Block, JT.Block); 1393 } 1394 1395 return Block; 1396} 1397 1398CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1399 CFGBlock* LoopSuccessor = NULL; 1400 1401 // Save local scope position because in case of condition variable ScopePos 1402 // won't be restored when traversing AST. 1403 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1404 1405 // Create local scope for init statement and possible condition variable. 1406 // Add destructor for init statement and condition variable. 1407 // Store scope position for continue statement. 1408 if (Stmt* Init = F->getInit()) 1409 addLocalScopeForStmt(Init); 1410 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1411 1412 if (VarDecl* VD = F->getConditionVariable()) 1413 addLocalScopeForVarDecl(VD); 1414 LocalScope::const_iterator ContinueScopePos = ScopePos; 1415 1416 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1417 1418 // "for" is a control-flow statement. Thus we stop processing the current 1419 // block. 1420 if (Block) { 1421 if (badCFG) 1422 return 0; 1423 LoopSuccessor = Block; 1424 } else 1425 LoopSuccessor = Succ; 1426 1427 // Save the current value for the break targets. 1428 // All breaks should go to the code following the loop. 1429 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1430 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1431 1432 // Because of short-circuit evaluation, the condition of the loop can span 1433 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1434 // evaluate the condition. 1435 CFGBlock* ExitConditionBlock = createBlock(false); 1436 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1437 1438 // Set the terminator for the "exit" condition block. 1439 ExitConditionBlock->setTerminator(F); 1440 1441 // Now add the actual condition to the condition block. Because the condition 1442 // itself may contain control-flow, new blocks may be created. 1443 if (Stmt* C = F->getCond()) { 1444 Block = ExitConditionBlock; 1445 EntryConditionBlock = addStmt(C); 1446 assert(Block == EntryConditionBlock || 1447 (Block == 0 && EntryConditionBlock == Succ)); 1448 1449 // If this block contains a condition variable, add both the condition 1450 // variable and initializer to the CFG. 1451 if (VarDecl *VD = F->getConditionVariable()) { 1452 if (Expr *Init = VD->getInit()) { 1453 autoCreateBlock(); 1454 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1455 EntryConditionBlock = addStmt(Init); 1456 assert(Block == EntryConditionBlock); 1457 } 1458 } 1459 1460 if (Block) { 1461 if (badCFG) 1462 return 0; 1463 } 1464 } 1465 1466 // The condition block is the implicit successor for the loop body as well as 1467 // any code above the loop. 1468 Succ = EntryConditionBlock; 1469 1470 // See if this is a known constant. 1471 TryResult KnownVal(true); 1472 1473 if (F->getCond()) 1474 KnownVal = TryEvaluateBool(F->getCond()); 1475 1476 // Now create the loop body. 1477 { 1478 assert(F->getBody()); 1479 1480 // Save the current values for Block, Succ, and continue targets. 1481 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1482 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1483 1484 // Create a new block to contain the (bottom) of the loop body. 1485 Block = NULL; 1486 1487 // Loop body should end with destructor of Condition variable (if any). 1488 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1489 1490 if (Stmt* I = F->getInc()) { 1491 // Generate increment code in its own basic block. This is the target of 1492 // continue statements. 1493 Succ = addStmt(I); 1494 } else { 1495 // No increment code. Create a special, empty, block that is used as the 1496 // target block for "looping back" to the start of the loop. 1497 assert(Succ == EntryConditionBlock); 1498 Succ = Block ? Block : createBlock(); 1499 } 1500 1501 // Finish up the increment (or empty) block if it hasn't been already. 1502 if (Block) { 1503 assert(Block == Succ); 1504 if (badCFG) 1505 return 0; 1506 Block = 0; 1507 } 1508 1509 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1510 1511 // The starting block for the loop increment is the block that should 1512 // represent the 'loop target' for looping back to the start of the loop. 1513 ContinueJumpTarget.Block->setLoopTarget(F); 1514 1515 // If body is not a compound statement create implicit scope 1516 // and add destructors. 1517 if (!isa<CompoundStmt>(F->getBody())) 1518 addLocalScopeAndDtors(F->getBody()); 1519 1520 // Now populate the body block, and in the process create new blocks as we 1521 // walk the body of the loop. 1522 CFGBlock* BodyBlock = addStmt(F->getBody()); 1523 1524 if (!BodyBlock) 1525 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1526 else if (badCFG) 1527 return 0; 1528 1529 // This new body block is a successor to our "exit" condition block. 1530 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1531 } 1532 1533 // Link up the condition block with the code that follows the loop. (the 1534 // false branch). 1535 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1536 1537 // If the loop contains initialization, create a new block for those 1538 // statements. This block can also contain statements that precede the loop. 1539 if (Stmt* I = F->getInit()) { 1540 Block = createBlock(); 1541 return addStmt(I); 1542 } else { 1543 // There is no loop initialization. We are thus basically a while loop. 1544 // NULL out Block to force lazy block construction. 1545 Block = NULL; 1546 Succ = EntryConditionBlock; 1547 return EntryConditionBlock; 1548 } 1549} 1550 1551CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1552 if (asc.alwaysAdd()) { 1553 autoCreateBlock(); 1554 AppendStmt(Block, M, asc); 1555 } 1556 return Visit(M->getBase(), 1557 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1558 : AddStmtChoice::AsLValueNotAlwaysAdd); 1559} 1560 1561CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1562 // Objective-C fast enumeration 'for' statements: 1563 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1564 // 1565 // for ( Type newVariable in collection_expression ) { statements } 1566 // 1567 // becomes: 1568 // 1569 // prologue: 1570 // 1. collection_expression 1571 // T. jump to loop_entry 1572 // loop_entry: 1573 // 1. side-effects of element expression 1574 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1575 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1576 // TB: 1577 // statements 1578 // T. jump to loop_entry 1579 // FB: 1580 // what comes after 1581 // 1582 // and 1583 // 1584 // Type existingItem; 1585 // for ( existingItem in expression ) { statements } 1586 // 1587 // becomes: 1588 // 1589 // the same with newVariable replaced with existingItem; the binding works 1590 // the same except that for one ObjCForCollectionStmt::getElement() returns 1591 // a DeclStmt and the other returns a DeclRefExpr. 1592 // 1593 1594 CFGBlock* LoopSuccessor = 0; 1595 1596 if (Block) { 1597 if (badCFG) 1598 return 0; 1599 LoopSuccessor = Block; 1600 Block = 0; 1601 } else 1602 LoopSuccessor = Succ; 1603 1604 // Build the condition blocks. 1605 CFGBlock* ExitConditionBlock = createBlock(false); 1606 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1607 1608 // Set the terminator for the "exit" condition block. 1609 ExitConditionBlock->setTerminator(S); 1610 1611 // The last statement in the block should be the ObjCForCollectionStmt, which 1612 // performs the actual binding to 'element' and determines if there are any 1613 // more items in the collection. 1614 AppendStmt(ExitConditionBlock, S); 1615 Block = ExitConditionBlock; 1616 1617 // Walk the 'element' expression to see if there are any side-effects. We 1618 // generate new blocks as necesary. We DON'T add the statement by default to 1619 // the CFG unless it contains control-flow. 1620 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1621 if (Block) { 1622 if (badCFG) 1623 return 0; 1624 Block = 0; 1625 } 1626 1627 // The condition block is the implicit successor for the loop body as well as 1628 // any code above the loop. 1629 Succ = EntryConditionBlock; 1630 1631 // Now create the true branch. 1632 { 1633 // Save the current values for Succ, continue and break targets. 1634 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1635 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1636 save_break(BreakJumpTarget); 1637 1638 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1639 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1640 1641 CFGBlock* BodyBlock = addStmt(S->getBody()); 1642 1643 if (!BodyBlock) 1644 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1645 else if (Block) { 1646 if (badCFG) 1647 return 0; 1648 } 1649 1650 // This new body block is a successor to our "exit" condition block. 1651 AddSuccessor(ExitConditionBlock, BodyBlock); 1652 } 1653 1654 // Link up the condition block with the code that follows the loop. 1655 // (the false branch). 1656 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1657 1658 // Now create a prologue block to contain the collection expression. 1659 Block = createBlock(); 1660 return addStmt(S->getCollection()); 1661} 1662 1663CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1664 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1665 1666 // Inline the body. 1667 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1668 1669 // The sync body starts its own basic block. This makes it a little easier 1670 // for diagnostic clients. 1671 if (SyncBlock) { 1672 if (badCFG) 1673 return 0; 1674 1675 Block = 0; 1676 Succ = SyncBlock; 1677 } 1678 1679 // Add the @synchronized to the CFG. 1680 autoCreateBlock(); 1681 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1682 1683 // Inline the sync expression. 1684 return addStmt(S->getSynchExpr()); 1685} 1686 1687CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1688 // FIXME 1689 return NYS(); 1690} 1691 1692CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1693 CFGBlock* LoopSuccessor = NULL; 1694 1695 // Save local scope position because in case of condition variable ScopePos 1696 // won't be restored when traversing AST. 1697 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1698 1699 // Create local scope for possible condition variable. 1700 // Store scope position for continue statement. 1701 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1702 if (VarDecl* VD = W->getConditionVariable()) { 1703 addLocalScopeForVarDecl(VD); 1704 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1705 } 1706 1707 // "while" is a control-flow statement. Thus we stop processing the current 1708 // block. 1709 if (Block) { 1710 if (badCFG) 1711 return 0; 1712 LoopSuccessor = Block; 1713 } else 1714 LoopSuccessor = Succ; 1715 1716 // Because of short-circuit evaluation, the condition of the loop can span 1717 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1718 // evaluate the condition. 1719 CFGBlock* ExitConditionBlock = createBlock(false); 1720 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1721 1722 // Set the terminator for the "exit" condition block. 1723 ExitConditionBlock->setTerminator(W); 1724 1725 // Now add the actual condition to the condition block. Because the condition 1726 // itself may contain control-flow, new blocks may be created. Thus we update 1727 // "Succ" after adding the condition. 1728 if (Stmt* C = W->getCond()) { 1729 Block = ExitConditionBlock; 1730 EntryConditionBlock = addStmt(C); 1731 assert(Block == EntryConditionBlock); 1732 1733 // If this block contains a condition variable, add both the condition 1734 // variable and initializer to the CFG. 1735 if (VarDecl *VD = W->getConditionVariable()) { 1736 if (Expr *Init = VD->getInit()) { 1737 autoCreateBlock(); 1738 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1739 EntryConditionBlock = addStmt(Init); 1740 assert(Block == EntryConditionBlock); 1741 } 1742 } 1743 1744 if (Block) { 1745 if (badCFG) 1746 return 0; 1747 } 1748 } 1749 1750 // The condition block is the implicit successor for the loop body as well as 1751 // any code above the loop. 1752 Succ = EntryConditionBlock; 1753 1754 // See if this is a known constant. 1755 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1756 1757 // Process the loop body. 1758 { 1759 assert(W->getBody()); 1760 1761 // Save the current values for Block, Succ, and continue and break targets 1762 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1763 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1764 save_break(BreakJumpTarget); 1765 1766 // Create an empty block to represent the transition block for looping back 1767 // to the head of the loop. 1768 Block = 0; 1769 assert(Succ == EntryConditionBlock); 1770 Succ = createBlock(); 1771 Succ->setLoopTarget(W); 1772 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1773 1774 // All breaks should go to the code following the loop. 1775 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1776 1777 // NULL out Block to force lazy instantiation of blocks for the body. 1778 Block = NULL; 1779 1780 // Loop body should end with destructor of Condition variable (if any). 1781 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1782 1783 // If body is not a compound statement create implicit scope 1784 // and add destructors. 1785 if (!isa<CompoundStmt>(W->getBody())) 1786 addLocalScopeAndDtors(W->getBody()); 1787 1788 // Create the body. The returned block is the entry to the loop body. 1789 CFGBlock* BodyBlock = addStmt(W->getBody()); 1790 1791 if (!BodyBlock) 1792 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1793 else if (Block) { 1794 if (badCFG) 1795 return 0; 1796 } 1797 1798 // Add the loop body entry as a successor to the condition. 1799 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1800 } 1801 1802 // Link up the condition block with the code that follows the loop. (the 1803 // false branch). 1804 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1805 1806 // There can be no more statements in the condition block since we loop back 1807 // to this block. NULL out Block to force lazy creation of another block. 1808 Block = NULL; 1809 1810 // Return the condition block, which is the dominating block for the loop. 1811 Succ = EntryConditionBlock; 1812 return EntryConditionBlock; 1813} 1814 1815 1816CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1817 // FIXME: For now we pretend that @catch and the code it contains does not 1818 // exit. 1819 return Block; 1820} 1821 1822CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1823 // FIXME: This isn't complete. We basically treat @throw like a return 1824 // statement. 1825 1826 // If we were in the middle of a block we stop processing that block. 1827 if (badCFG) 1828 return 0; 1829 1830 // Create the new block. 1831 Block = createBlock(false); 1832 1833 // The Exit block is the only successor. 1834 AddSuccessor(Block, &cfg->getExit()); 1835 1836 // Add the statement to the block. This may create new blocks if S contains 1837 // control-flow (short-circuit operations). 1838 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1839} 1840 1841CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1842 // If we were in the middle of a block we stop processing that block. 1843 if (badCFG) 1844 return 0; 1845 1846 // Create the new block. 1847 Block = createBlock(false); 1848 1849 if (TryTerminatedBlock) 1850 // The current try statement is the only successor. 1851 AddSuccessor(Block, TryTerminatedBlock); 1852 else 1853 // otherwise the Exit block is the only successor. 1854 AddSuccessor(Block, &cfg->getExit()); 1855 1856 // Add the statement to the block. This may create new blocks if S contains 1857 // control-flow (short-circuit operations). 1858 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1859} 1860 1861CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1862 CFGBlock* LoopSuccessor = NULL; 1863 1864 // "do...while" is a control-flow statement. Thus we stop processing the 1865 // current block. 1866 if (Block) { 1867 if (badCFG) 1868 return 0; 1869 LoopSuccessor = Block; 1870 } else 1871 LoopSuccessor = Succ; 1872 1873 // Because of short-circuit evaluation, the condition of the loop can span 1874 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1875 // evaluate the condition. 1876 CFGBlock* ExitConditionBlock = createBlock(false); 1877 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1878 1879 // Set the terminator for the "exit" condition block. 1880 ExitConditionBlock->setTerminator(D); 1881 1882 // Now add the actual condition to the condition block. Because the condition 1883 // itself may contain control-flow, new blocks may be created. 1884 if (Stmt* C = D->getCond()) { 1885 Block = ExitConditionBlock; 1886 EntryConditionBlock = addStmt(C); 1887 if (Block) { 1888 if (badCFG) 1889 return 0; 1890 } 1891 } 1892 1893 // The condition block is the implicit successor for the loop body. 1894 Succ = EntryConditionBlock; 1895 1896 // See if this is a known constant. 1897 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1898 1899 // Process the loop body. 1900 CFGBlock* BodyBlock = NULL; 1901 { 1902 assert(D->getBody()); 1903 1904 // Save the current values for Block, Succ, and continue and break targets 1905 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1906 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1907 save_break(BreakJumpTarget); 1908 1909 // All continues within this loop should go to the condition block 1910 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1911 1912 // All breaks should go to the code following the loop. 1913 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1914 1915 // NULL out Block to force lazy instantiation of blocks for the body. 1916 Block = NULL; 1917 1918 // If body is not a compound statement create implicit scope 1919 // and add destructors. 1920 if (!isa<CompoundStmt>(D->getBody())) 1921 addLocalScopeAndDtors(D->getBody()); 1922 1923 // Create the body. The returned block is the entry to the loop body. 1924 BodyBlock = addStmt(D->getBody()); 1925 1926 if (!BodyBlock) 1927 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1928 else if (Block) { 1929 if (badCFG) 1930 return 0; 1931 } 1932 1933 if (!KnownVal.isFalse()) { 1934 // Add an intermediate block between the BodyBlock and the 1935 // ExitConditionBlock to represent the "loop back" transition. Create an 1936 // empty block to represent the transition block for looping back to the 1937 // head of the loop. 1938 // FIXME: Can we do this more efficiently without adding another block? 1939 Block = NULL; 1940 Succ = BodyBlock; 1941 CFGBlock *LoopBackBlock = createBlock(); 1942 LoopBackBlock->setLoopTarget(D); 1943 1944 // Add the loop body entry as a successor to the condition. 1945 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1946 } 1947 else 1948 AddSuccessor(ExitConditionBlock, NULL); 1949 } 1950 1951 // Link up the condition block with the code that follows the loop. 1952 // (the false branch). 1953 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1954 1955 // There can be no more statements in the body block(s) since we loop back to 1956 // the body. NULL out Block to force lazy creation of another block. 1957 Block = NULL; 1958 1959 // Return the loop body, which is the dominating block for the loop. 1960 Succ = BodyBlock; 1961 return BodyBlock; 1962} 1963 1964CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1965 // "continue" is a control-flow statement. Thus we stop processing the 1966 // current block. 1967 if (badCFG) 1968 return 0; 1969 1970 // Now create a new block that ends with the continue statement. 1971 Block = createBlock(false); 1972 Block->setTerminator(C); 1973 1974 // If there is no target for the continue, then we are looking at an 1975 // incomplete AST. This means the CFG cannot be constructed. 1976 if (ContinueJumpTarget.Block) { 1977 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1978 AddSuccessor(Block, ContinueJumpTarget.Block); 1979 } else 1980 badCFG = true; 1981 1982 return Block; 1983} 1984 1985CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1986 AddStmtChoice asc) { 1987 1988 if (asc.alwaysAdd()) { 1989 autoCreateBlock(); 1990 AppendStmt(Block, E); 1991 } 1992 1993 // VLA types have expressions that must be evaluated. 1994 if (E->isArgumentType()) { 1995 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1996 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1997 addStmt(VA->getSizeExpr()); 1998 } 1999 2000 return Block; 2001} 2002 2003/// VisitStmtExpr - Utility method to handle (nested) statement 2004/// expressions (a GCC extension). 2005CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2006 if (asc.alwaysAdd()) { 2007 autoCreateBlock(); 2008 AppendStmt(Block, SE); 2009 } 2010 return VisitCompoundStmt(SE->getSubStmt()); 2011} 2012 2013CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2014 // "switch" is a control-flow statement. Thus we stop processing the current 2015 // block. 2016 CFGBlock* SwitchSuccessor = NULL; 2017 2018 // Save local scope position because in case of condition variable ScopePos 2019 // won't be restored when traversing AST. 2020 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2021 2022 // Create local scope for possible condition variable. 2023 // Store scope position. Add implicit destructor. 2024 if (VarDecl* VD = Terminator->getConditionVariable()) { 2025 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2026 addLocalScopeForVarDecl(VD); 2027 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2028 } 2029 2030 if (Block) { 2031 if (badCFG) 2032 return 0; 2033 SwitchSuccessor = Block; 2034 } else SwitchSuccessor = Succ; 2035 2036 // Save the current "switch" context. 2037 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2038 save_default(DefaultCaseBlock); 2039 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2040 2041 // Set the "default" case to be the block after the switch statement. If the 2042 // switch statement contains a "default:", this value will be overwritten with 2043 // the block for that code. 2044 DefaultCaseBlock = SwitchSuccessor; 2045 2046 // Create a new block that will contain the switch statement. 2047 SwitchTerminatedBlock = createBlock(false); 2048 2049 // Now process the switch body. The code after the switch is the implicit 2050 // successor. 2051 Succ = SwitchSuccessor; 2052 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2053 2054 // When visiting the body, the case statements should automatically get linked 2055 // up to the switch. We also don't keep a pointer to the body, since all 2056 // control-flow from the switch goes to case/default statements. 2057 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2058 Block = NULL; 2059 2060 // If body is not a compound statement create implicit scope 2061 // and add destructors. 2062 if (!isa<CompoundStmt>(Terminator->getBody())) 2063 addLocalScopeAndDtors(Terminator->getBody()); 2064 2065 addStmt(Terminator->getBody()); 2066 if (Block) { 2067 if (badCFG) 2068 return 0; 2069 } 2070 2071 // If we have no "default:" case, the default transition is to the code 2072 // following the switch body. 2073 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2074 2075 // Add the terminator and condition in the switch block. 2076 SwitchTerminatedBlock->setTerminator(Terminator); 2077 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2078 Block = SwitchTerminatedBlock; 2079 Block = addStmt(Terminator->getCond()); 2080 2081 // Finally, if the SwitchStmt contains a condition variable, add both the 2082 // SwitchStmt and the condition variable initialization to the CFG. 2083 if (VarDecl *VD = Terminator->getConditionVariable()) { 2084 if (Expr *Init = VD->getInit()) { 2085 autoCreateBlock(); 2086 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2087 addStmt(Init); 2088 } 2089 } 2090 2091 return Block; 2092} 2093 2094CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2095 // CaseStmts are essentially labels, so they are the first statement in a 2096 // block. 2097 CFGBlock *TopBlock = 0, *LastBlock = 0; 2098 2099 if (Stmt *Sub = CS->getSubStmt()) { 2100 // For deeply nested chains of CaseStmts, instead of doing a recursion 2101 // (which can blow out the stack), manually unroll and create blocks 2102 // along the way. 2103 while (isa<CaseStmt>(Sub)) { 2104 CFGBlock *CurrentBlock = createBlock(false); 2105 CurrentBlock->setLabel(CS); 2106 2107 if (TopBlock) 2108 AddSuccessor(LastBlock, CurrentBlock); 2109 else 2110 TopBlock = CurrentBlock; 2111 2112 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2113 LastBlock = CurrentBlock; 2114 2115 CS = cast<CaseStmt>(Sub); 2116 Sub = CS->getSubStmt(); 2117 } 2118 2119 addStmt(Sub); 2120 } 2121 2122 CFGBlock* CaseBlock = Block; 2123 if (!CaseBlock) 2124 CaseBlock = createBlock(); 2125 2126 // Cases statements partition blocks, so this is the top of the basic block we 2127 // were processing (the "case XXX:" is the label). 2128 CaseBlock->setLabel(CS); 2129 2130 if (badCFG) 2131 return 0; 2132 2133 // Add this block to the list of successors for the block with the switch 2134 // statement. 2135 assert(SwitchTerminatedBlock); 2136 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2137 2138 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2139 Block = NULL; 2140 2141 if (TopBlock) { 2142 AddSuccessor(LastBlock, CaseBlock); 2143 Succ = TopBlock; 2144 } 2145 else { 2146 // This block is now the implicit successor of other blocks. 2147 Succ = CaseBlock; 2148 } 2149 2150 return Succ; 2151} 2152 2153CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2154 if (Terminator->getSubStmt()) 2155 addStmt(Terminator->getSubStmt()); 2156 2157 DefaultCaseBlock = Block; 2158 2159 if (!DefaultCaseBlock) 2160 DefaultCaseBlock = createBlock(); 2161 2162 // Default statements partition blocks, so this is the top of the basic block 2163 // we were processing (the "default:" is the label). 2164 DefaultCaseBlock->setLabel(Terminator); 2165 2166 if (badCFG) 2167 return 0; 2168 2169 // Unlike case statements, we don't add the default block to the successors 2170 // for the switch statement immediately. This is done when we finish 2171 // processing the switch statement. This allows for the default case 2172 // (including a fall-through to the code after the switch statement) to always 2173 // be the last successor of a switch-terminated block. 2174 2175 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2176 Block = NULL; 2177 2178 // This block is now the implicit successor of other blocks. 2179 Succ = DefaultCaseBlock; 2180 2181 return DefaultCaseBlock; 2182} 2183 2184CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2185 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2186 // current block. 2187 CFGBlock* TrySuccessor = NULL; 2188 2189 if (Block) { 2190 if (badCFG) 2191 return 0; 2192 TrySuccessor = Block; 2193 } else TrySuccessor = Succ; 2194 2195 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2196 2197 // Create a new block that will contain the try statement. 2198 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2199 // Add the terminator in the try block. 2200 NewTryTerminatedBlock->setTerminator(Terminator); 2201 2202 bool HasCatchAll = false; 2203 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2204 // The code after the try is the implicit successor. 2205 Succ = TrySuccessor; 2206 CXXCatchStmt *CS = Terminator->getHandler(h); 2207 if (CS->getExceptionDecl() == 0) { 2208 HasCatchAll = true; 2209 } 2210 Block = NULL; 2211 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2212 if (CatchBlock == 0) 2213 return 0; 2214 // Add this block to the list of successors for the block with the try 2215 // statement. 2216 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2217 } 2218 if (!HasCatchAll) { 2219 if (PrevTryTerminatedBlock) 2220 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2221 else 2222 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2223 } 2224 2225 // The code after the try is the implicit successor. 2226 Succ = TrySuccessor; 2227 2228 // Save the current "try" context. 2229 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2230 TryTerminatedBlock = NewTryTerminatedBlock; 2231 2232 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2233 Block = NULL; 2234 Block = addStmt(Terminator->getTryBlock()); 2235 return Block; 2236} 2237 2238CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2239 // CXXCatchStmt are treated like labels, so they are the first statement in a 2240 // block. 2241 2242 // Save local scope position because in case of exception variable ScopePos 2243 // won't be restored when traversing AST. 2244 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2245 2246 // Create local scope for possible exception variable. 2247 // Store scope position. Add implicit destructor. 2248 if (VarDecl* VD = CS->getExceptionDecl()) { 2249 LocalScope::const_iterator BeginScopePos = ScopePos; 2250 addLocalScopeForVarDecl(VD); 2251 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2252 } 2253 2254 if (CS->getHandlerBlock()) 2255 addStmt(CS->getHandlerBlock()); 2256 2257 CFGBlock* CatchBlock = Block; 2258 if (!CatchBlock) 2259 CatchBlock = createBlock(); 2260 2261 CatchBlock->setLabel(CS); 2262 2263 if (badCFG) 2264 return 0; 2265 2266 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2267 Block = NULL; 2268 2269 return CatchBlock; 2270} 2271 2272CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2273 AddStmtChoice asc) { 2274 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2275 : AddStmtChoice::AlwaysAdd; 2276 autoCreateBlock(); 2277 AppendStmt(Block, C, AddStmtChoice(K)); 2278 return VisitChildren(C); 2279} 2280 2281CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2282 // Lazily create the indirect-goto dispatch block if there isn't one already. 2283 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2284 2285 if (!IBlock) { 2286 IBlock = createBlock(false); 2287 cfg->setIndirectGotoBlock(IBlock); 2288 } 2289 2290 // IndirectGoto is a control-flow statement. Thus we stop processing the 2291 // current block and create a new one. 2292 if (badCFG) 2293 return 0; 2294 2295 Block = createBlock(false); 2296 Block->setTerminator(I); 2297 AddSuccessor(Block, IBlock); 2298 return addStmt(I->getTarget()); 2299} 2300 2301} // end anonymous namespace 2302 2303/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2304/// no successors or predecessors. If this is the first block created in the 2305/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2306CFGBlock* CFG::createBlock() { 2307 bool first_block = begin() == end(); 2308 2309 // Create the block. 2310 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2311 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2312 Blocks.push_back(Mem, BlkBVC); 2313 2314 // If this is the first block, set it as the Entry and Exit. 2315 if (first_block) 2316 Entry = Exit = &back(); 2317 2318 // Return the block. 2319 return &back(); 2320} 2321 2322/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2323/// CFG is returned to the caller. 2324CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2325 BuildOptions BO) { 2326 CFGBuilder Builder; 2327 return Builder.buildCFG(D, Statement, C, BO); 2328} 2329 2330//===----------------------------------------------------------------------===// 2331// CFG: Queries for BlkExprs. 2332//===----------------------------------------------------------------------===// 2333 2334namespace { 2335 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2336} 2337 2338static void FindSubExprAssignments(Stmt *S, 2339 llvm::SmallPtrSet<Expr*,50>& Set) { 2340 if (!S) 2341 return; 2342 2343 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2344 Stmt *child = *I; 2345 if (!child) 2346 continue; 2347 2348 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2349 if (B->isAssignmentOp()) Set.insert(B); 2350 2351 FindSubExprAssignments(child, Set); 2352 } 2353} 2354 2355static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2356 BlkExprMapTy* M = new BlkExprMapTy(); 2357 2358 // Look for assignments that are used as subexpressions. These are the only 2359 // assignments that we want to *possibly* register as a block-level 2360 // expression. Basically, if an assignment occurs both in a subexpression and 2361 // at the block-level, it is a block-level expression. 2362 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2363 2364 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2365 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2366 if (CFGStmt S = BI->getAs<CFGStmt>()) 2367 FindSubExprAssignments(S, SubExprAssignments); 2368 2369 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2370 2371 // Iterate over the statements again on identify the Expr* and Stmt* at the 2372 // block-level that are block-level expressions. 2373 2374 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2375 CFGStmt CS = BI->getAs<CFGStmt>(); 2376 if (!CS.isValid()) 2377 continue; 2378 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2379 2380 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2381 // Assignment expressions that are not nested within another 2382 // expression are really "statements" whose value is never used by 2383 // another expression. 2384 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2385 continue; 2386 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2387 // Special handling for statement expressions. The last statement in 2388 // the statement expression is also a block-level expr. 2389 const CompoundStmt* C = Terminator->getSubStmt(); 2390 if (!C->body_empty()) { 2391 unsigned x = M->size(); 2392 (*M)[C->body_back()] = x; 2393 } 2394 } 2395 2396 unsigned x = M->size(); 2397 (*M)[Exp] = x; 2398 } 2399 } 2400 2401 // Look at terminators. The condition is a block-level expression. 2402 2403 Stmt* S = (*I)->getTerminatorCondition(); 2404 2405 if (S && M->find(S) == M->end()) { 2406 unsigned x = M->size(); 2407 (*M)[S] = x; 2408 } 2409 } 2410 2411 return M; 2412} 2413 2414CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2415 assert(S != NULL); 2416 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2417 2418 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2419 BlkExprMapTy::iterator I = M->find(S); 2420 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2421} 2422 2423unsigned CFG::getNumBlkExprs() { 2424 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2425 return M->size(); 2426 else { 2427 // We assume callers interested in the number of BlkExprs will want 2428 // the map constructed if it doesn't already exist. 2429 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2430 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2431 } 2432} 2433 2434//===----------------------------------------------------------------------===// 2435// Filtered walking of the CFG. 2436//===----------------------------------------------------------------------===// 2437 2438bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2439 const CFGBlock *From, const CFGBlock *To) { 2440 2441 if (F.IgnoreDefaultsWithCoveredEnums) { 2442 // If the 'To' has no label or is labeled but the label isn't a 2443 // CaseStmt then filter this edge. 2444 if (const SwitchStmt *S = 2445 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2446 if (S->isAllEnumCasesCovered()) { 2447 const Stmt *L = To->getLabel(); 2448 if (!L || !isa<CaseStmt>(L)) 2449 return true; 2450 } 2451 } 2452 } 2453 2454 return false; 2455} 2456 2457//===----------------------------------------------------------------------===// 2458// Cleanup: CFG dstor. 2459//===----------------------------------------------------------------------===// 2460 2461CFG::~CFG() { 2462 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2463} 2464 2465//===----------------------------------------------------------------------===// 2466// CFG pretty printing 2467//===----------------------------------------------------------------------===// 2468 2469namespace { 2470 2471class StmtPrinterHelper : public PrinterHelper { 2472 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2473 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2474 StmtMapTy StmtMap; 2475 DeclMapTy DeclMap; 2476 signed CurrentBlock; 2477 unsigned CurrentStmt; 2478 const LangOptions &LangOpts; 2479public: 2480 2481 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2482 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2483 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2484 unsigned j = 1; 2485 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2486 BI != BEnd; ++BI, ++j ) { 2487 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2488 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2489 StmtMap[SE] = P; 2490 2491 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2492 DeclMap[DS->getSingleDecl()] = P; 2493 2494 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2495 if (VarDecl* VD = IS->getConditionVariable()) 2496 DeclMap[VD] = P; 2497 2498 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2499 if (VarDecl* VD = FS->getConditionVariable()) 2500 DeclMap[VD] = P; 2501 2502 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2503 if (VarDecl* VD = WS->getConditionVariable()) 2504 DeclMap[VD] = P; 2505 2506 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2507 if (VarDecl* VD = SS->getConditionVariable()) 2508 DeclMap[VD] = P; 2509 2510 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2511 if (VarDecl* VD = CS->getExceptionDecl()) 2512 DeclMap[VD] = P; 2513 } 2514 } 2515 } 2516 } 2517 } 2518 2519 virtual ~StmtPrinterHelper() {} 2520 2521 const LangOptions &getLangOpts() const { return LangOpts; } 2522 void setBlockID(signed i) { CurrentBlock = i; } 2523 void setStmtID(unsigned i) { CurrentStmt = i; } 2524 2525 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2526 StmtMapTy::iterator I = StmtMap.find(S); 2527 2528 if (I == StmtMap.end()) 2529 return false; 2530 2531 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2532 && I->second.second == CurrentStmt) { 2533 return false; 2534 } 2535 2536 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2537 return true; 2538 } 2539 2540 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2541 DeclMapTy::iterator I = DeclMap.find(D); 2542 2543 if (I == DeclMap.end()) 2544 return false; 2545 2546 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2547 && I->second.second == CurrentStmt) { 2548 return false; 2549 } 2550 2551 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2552 return true; 2553 } 2554}; 2555} // end anonymous namespace 2556 2557 2558namespace { 2559class CFGBlockTerminatorPrint 2560 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2561 2562 llvm::raw_ostream& OS; 2563 StmtPrinterHelper* Helper; 2564 PrintingPolicy Policy; 2565public: 2566 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2567 const PrintingPolicy &Policy) 2568 : OS(os), Helper(helper), Policy(Policy) {} 2569 2570 void VisitIfStmt(IfStmt* I) { 2571 OS << "if "; 2572 I->getCond()->printPretty(OS,Helper,Policy); 2573 } 2574 2575 // Default case. 2576 void VisitStmt(Stmt* Terminator) { 2577 Terminator->printPretty(OS, Helper, Policy); 2578 } 2579 2580 void VisitForStmt(ForStmt* F) { 2581 OS << "for (" ; 2582 if (F->getInit()) 2583 OS << "..."; 2584 OS << "; "; 2585 if (Stmt* C = F->getCond()) 2586 C->printPretty(OS, Helper, Policy); 2587 OS << "; "; 2588 if (F->getInc()) 2589 OS << "..."; 2590 OS << ")"; 2591 } 2592 2593 void VisitWhileStmt(WhileStmt* W) { 2594 OS << "while " ; 2595 if (Stmt* C = W->getCond()) 2596 C->printPretty(OS, Helper, Policy); 2597 } 2598 2599 void VisitDoStmt(DoStmt* D) { 2600 OS << "do ... while "; 2601 if (Stmt* C = D->getCond()) 2602 C->printPretty(OS, Helper, Policy); 2603 } 2604 2605 void VisitSwitchStmt(SwitchStmt* Terminator) { 2606 OS << "switch "; 2607 Terminator->getCond()->printPretty(OS, Helper, Policy); 2608 } 2609 2610 void VisitCXXTryStmt(CXXTryStmt* CS) { 2611 OS << "try ..."; 2612 } 2613 2614 void VisitConditionalOperator(ConditionalOperator* C) { 2615 C->getCond()->printPretty(OS, Helper, Policy); 2616 OS << " ? ... : ..."; 2617 } 2618 2619 void VisitChooseExpr(ChooseExpr* C) { 2620 OS << "__builtin_choose_expr( "; 2621 C->getCond()->printPretty(OS, Helper, Policy); 2622 OS << " )"; 2623 } 2624 2625 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2626 OS << "goto *"; 2627 I->getTarget()->printPretty(OS, Helper, Policy); 2628 } 2629 2630 void VisitBinaryOperator(BinaryOperator* B) { 2631 if (!B->isLogicalOp()) { 2632 VisitExpr(B); 2633 return; 2634 } 2635 2636 B->getLHS()->printPretty(OS, Helper, Policy); 2637 2638 switch (B->getOpcode()) { 2639 case BO_LOr: 2640 OS << " || ..."; 2641 return; 2642 case BO_LAnd: 2643 OS << " && ..."; 2644 return; 2645 default: 2646 assert(false && "Invalid logical operator."); 2647 } 2648 } 2649 2650 void VisitExpr(Expr* E) { 2651 E->printPretty(OS, Helper, Policy); 2652 } 2653}; 2654} // end anonymous namespace 2655 2656static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2657 const CFGElement &E) { 2658 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2659 Stmt *S = CS; 2660 2661 if (Helper) { 2662 2663 // special printing for statement-expressions. 2664 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2665 CompoundStmt* Sub = SE->getSubStmt(); 2666 2667 if (Sub->child_begin() != Sub->child_end()) { 2668 OS << "({ ... ; "; 2669 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2670 OS << " })\n"; 2671 return; 2672 } 2673 } 2674 // special printing for comma expressions. 2675 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2676 if (B->getOpcode() == BO_Comma) { 2677 OS << "... , "; 2678 Helper->handledStmt(B->getRHS(),OS); 2679 OS << '\n'; 2680 return; 2681 } 2682 } 2683 } 2684 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2685 2686 if (isa<CXXOperatorCallExpr>(S)) { 2687 OS << " (OperatorCall)"; 2688 } 2689 else if (isa<CXXBindTemporaryExpr>(S)) { 2690 OS << " (BindTemporary)"; 2691 } 2692 2693 // Expressions need a newline. 2694 if (isa<Expr>(S)) 2695 OS << '\n'; 2696 2697 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2698 CXXBaseOrMemberInitializer* I = IE; 2699 if (I->isBaseInitializer()) 2700 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2701 else OS << I->getMember()->getName(); 2702 2703 OS << "("; 2704 if (Expr* IE = I->getInit()) 2705 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2706 OS << ")"; 2707 2708 if (I->isBaseInitializer()) 2709 OS << " (Base initializer)\n"; 2710 else OS << " (Member initializer)\n"; 2711 2712 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2713 VarDecl* VD = DE.getVarDecl(); 2714 Helper->handleDecl(VD, OS); 2715 2716 const Type* T = VD->getType().getTypePtr(); 2717 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2718 T = RT->getPointeeType().getTypePtr(); 2719 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 2720 T = ET; 2721 2722 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2723 OS << " (Implicit destructor)\n"; 2724 2725 } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { 2726 const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); 2727 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 2728 OS << " (Base object destructor)\n"; 2729 2730 } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { 2731 FieldDecl *FD = ME.getFieldDecl(); 2732 OS << "this->" << FD->getName(); 2733 OS << ".~" << FD->getType()->getAsCXXRecordDecl()->getName() << "()"; 2734 OS << " (Member object destructor)\n"; 2735 } 2736 } 2737 2738static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2739 const CFGBlock& B, 2740 StmtPrinterHelper* Helper, bool print_edges) { 2741 2742 if (Helper) Helper->setBlockID(B.getBlockID()); 2743 2744 // Print the header. 2745 OS << "\n [ B" << B.getBlockID(); 2746 2747 if (&B == &cfg->getEntry()) 2748 OS << " (ENTRY) ]\n"; 2749 else if (&B == &cfg->getExit()) 2750 OS << " (EXIT) ]\n"; 2751 else if (&B == cfg->getIndirectGotoBlock()) 2752 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2753 else 2754 OS << " ]\n"; 2755 2756 // Print the label of this block. 2757 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2758 2759 if (print_edges) 2760 OS << " "; 2761 2762 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2763 OS << L->getName(); 2764 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2765 OS << "case "; 2766 C->getLHS()->printPretty(OS, Helper, 2767 PrintingPolicy(Helper->getLangOpts())); 2768 if (C->getRHS()) { 2769 OS << " ... "; 2770 C->getRHS()->printPretty(OS, Helper, 2771 PrintingPolicy(Helper->getLangOpts())); 2772 } 2773 } else if (isa<DefaultStmt>(Label)) 2774 OS << "default"; 2775 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2776 OS << "catch ("; 2777 if (CS->getExceptionDecl()) 2778 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2779 0); 2780 else 2781 OS << "..."; 2782 OS << ")"; 2783 2784 } else 2785 assert(false && "Invalid label statement in CFGBlock."); 2786 2787 OS << ":\n"; 2788 } 2789 2790 // Iterate through the statements in the block and print them. 2791 unsigned j = 1; 2792 2793 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2794 I != E ; ++I, ++j ) { 2795 2796 // Print the statement # in the basic block and the statement itself. 2797 if (print_edges) 2798 OS << " "; 2799 2800 OS << llvm::format("%3d", j) << ": "; 2801 2802 if (Helper) 2803 Helper->setStmtID(j); 2804 2805 print_elem(OS,Helper,*I); 2806 } 2807 2808 // Print the terminator of this block. 2809 if (B.getTerminator()) { 2810 if (print_edges) 2811 OS << " "; 2812 2813 OS << " T: "; 2814 2815 if (Helper) Helper->setBlockID(-1); 2816 2817 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2818 PrintingPolicy(Helper->getLangOpts())); 2819 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2820 OS << '\n'; 2821 } 2822 2823 if (print_edges) { 2824 // Print the predecessors of this block. 2825 OS << " Predecessors (" << B.pred_size() << "):"; 2826 unsigned i = 0; 2827 2828 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2829 I != E; ++I, ++i) { 2830 2831 if (i == 8 || (i-8) == 0) 2832 OS << "\n "; 2833 2834 OS << " B" << (*I)->getBlockID(); 2835 } 2836 2837 OS << '\n'; 2838 2839 // Print the successors of this block. 2840 OS << " Successors (" << B.succ_size() << "):"; 2841 i = 0; 2842 2843 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2844 I != E; ++I, ++i) { 2845 2846 if (i == 8 || (i-8) % 10 == 0) 2847 OS << "\n "; 2848 2849 if (*I) 2850 OS << " B" << (*I)->getBlockID(); 2851 else 2852 OS << " NULL"; 2853 } 2854 2855 OS << '\n'; 2856 } 2857} 2858 2859 2860/// dump - A simple pretty printer of a CFG that outputs to stderr. 2861void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2862 2863/// print - A simple pretty printer of a CFG that outputs to an ostream. 2864void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2865 StmtPrinterHelper Helper(this, LO); 2866 2867 // Print the entry block. 2868 print_block(OS, this, getEntry(), &Helper, true); 2869 2870 // Iterate through the CFGBlocks and print them one by one. 2871 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2872 // Skip the entry block, because we already printed it. 2873 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2874 continue; 2875 2876 print_block(OS, this, **I, &Helper, true); 2877 } 2878 2879 // Print the exit block. 2880 print_block(OS, this, getExit(), &Helper, true); 2881 OS.flush(); 2882} 2883 2884/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2885void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2886 print(llvm::errs(), cfg, LO); 2887} 2888 2889/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2890/// Generally this will only be called from CFG::print. 2891void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2892 const LangOptions &LO) const { 2893 StmtPrinterHelper Helper(cfg, LO); 2894 print_block(OS, cfg, *this, &Helper, true); 2895} 2896 2897/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2898void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2899 const LangOptions &LO) const { 2900 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2901 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2902} 2903 2904Stmt* CFGBlock::getTerminatorCondition() { 2905 2906 if (!Terminator) 2907 return NULL; 2908 2909 Expr* E = NULL; 2910 2911 switch (Terminator->getStmtClass()) { 2912 default: 2913 break; 2914 2915 case Stmt::ForStmtClass: 2916 E = cast<ForStmt>(Terminator)->getCond(); 2917 break; 2918 2919 case Stmt::WhileStmtClass: 2920 E = cast<WhileStmt>(Terminator)->getCond(); 2921 break; 2922 2923 case Stmt::DoStmtClass: 2924 E = cast<DoStmt>(Terminator)->getCond(); 2925 break; 2926 2927 case Stmt::IfStmtClass: 2928 E = cast<IfStmt>(Terminator)->getCond(); 2929 break; 2930 2931 case Stmt::ChooseExprClass: 2932 E = cast<ChooseExpr>(Terminator)->getCond(); 2933 break; 2934 2935 case Stmt::IndirectGotoStmtClass: 2936 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2937 break; 2938 2939 case Stmt::SwitchStmtClass: 2940 E = cast<SwitchStmt>(Terminator)->getCond(); 2941 break; 2942 2943 case Stmt::ConditionalOperatorClass: 2944 E = cast<ConditionalOperator>(Terminator)->getCond(); 2945 break; 2946 2947 case Stmt::BinaryOperatorClass: // '&&' and '||' 2948 E = cast<BinaryOperator>(Terminator)->getLHS(); 2949 break; 2950 2951 case Stmt::ObjCForCollectionStmtClass: 2952 return Terminator; 2953 } 2954 2955 return E ? E->IgnoreParens() : NULL; 2956} 2957 2958bool CFGBlock::hasBinaryBranchTerminator() const { 2959 2960 if (!Terminator) 2961 return false; 2962 2963 Expr* E = NULL; 2964 2965 switch (Terminator->getStmtClass()) { 2966 default: 2967 return false; 2968 2969 case Stmt::ForStmtClass: 2970 case Stmt::WhileStmtClass: 2971 case Stmt::DoStmtClass: 2972 case Stmt::IfStmtClass: 2973 case Stmt::ChooseExprClass: 2974 case Stmt::ConditionalOperatorClass: 2975 case Stmt::BinaryOperatorClass: 2976 return true; 2977 } 2978 2979 return E ? E->IgnoreParens() : NULL; 2980} 2981 2982 2983//===----------------------------------------------------------------------===// 2984// CFG Graphviz Visualization 2985//===----------------------------------------------------------------------===// 2986 2987 2988#ifndef NDEBUG 2989static StmtPrinterHelper* GraphHelper; 2990#endif 2991 2992void CFG::viewCFG(const LangOptions &LO) const { 2993#ifndef NDEBUG 2994 StmtPrinterHelper H(this, LO); 2995 GraphHelper = &H; 2996 llvm::ViewGraph(this,"CFG"); 2997 GraphHelper = NULL; 2998#endif 2999} 3000 3001namespace llvm { 3002template<> 3003struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3004 3005 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3006 3007 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3008 3009#ifndef NDEBUG 3010 std::string OutSStr; 3011 llvm::raw_string_ostream Out(OutSStr); 3012 print_block(Out,Graph, *Node, GraphHelper, false); 3013 std::string& OutStr = Out.str(); 3014 3015 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3016 3017 // Process string output to make it nicer... 3018 for (unsigned i = 0; i != OutStr.length(); ++i) 3019 if (OutStr[i] == '\n') { // Left justify 3020 OutStr[i] = '\\'; 3021 OutStr.insert(OutStr.begin()+i+1, 'l'); 3022 } 3023 3024 return OutStr; 3025#else 3026 return ""; 3027#endif 3028 } 3029}; 3030} // end namespace llvm 3031