CFG.cpp revision 8c5e5d6d8a316af5a9842169f541cac49717887d
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39class AddStmtChoice { 40public: 41 enum Kind { NotAlwaysAdd = 0, 42 AlwaysAdd = 1, 43 AsLValueNotAlwaysAdd = 2, 44 AlwaysAddAsLValue = 3 }; 45 46 AddStmtChoice(Kind kind) : k(kind) {} 47 48 bool alwaysAdd() const { return (unsigned)k & 0x1; } 49 bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } 50 51private: 52 Kind k; 53}; 54 55/// LocalScope - Node in tree of local scopes created for C++ implicit 56/// destructor calls generation. It contains list of automatic variables 57/// declared in the scope and link to position in previous scope this scope 58/// began in. 59/// 60/// The process of creating local scopes is as follows: 61/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 62/// - Before processing statements in scope (e.g. CompoundStmt) create 63/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 64/// and set CFGBuilder::ScopePos to the end of new scope, 65/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 66/// at this VarDecl, 67/// - For every normal (without jump) end of scope add to CFGBlock destructors 68/// for objects in the current scope, 69/// - For every jump add to CFGBlock destructors for objects 70/// between CFGBuilder::ScopePos and local scope position saved for jump 71/// target. Thanks to C++ restrictions on goto jumps we can be sure that 72/// jump target position will be on the path to root from CFGBuilder::ScopePos 73/// (adding any variable that doesn't need constructor to be called to 74/// LocalScope can break this assumption), 75/// 76class LocalScope { 77public: 78 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 79 80 /// const_iterator - Iterates local scope backwards and jumps to previous 81 /// scope on reaching the beginning of currently iterated scope. 82 class const_iterator { 83 const LocalScope* Scope; 84 85 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 86 /// Invalid iterator (with null Scope) has VarIter equal to 0. 87 unsigned VarIter; 88 89 public: 90 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 91 /// Incrementing invalid iterator is allowed and will result in invalid 92 /// iterator. 93 const_iterator() 94 : Scope(NULL), VarIter(0) {} 95 96 /// Create valid iterator. In case when S.Prev is an invalid iterator and 97 /// I is equal to 0, this will create invalid iterator. 98 const_iterator(const LocalScope& S, unsigned I) 99 : Scope(&S), VarIter(I) { 100 // Iterator to "end" of scope is not allowed. Handle it by going up 101 // in scopes tree possibly up to invalid iterator in the root. 102 if (VarIter == 0 && Scope) 103 *this = Scope->Prev; 104 } 105 106 VarDecl* const* operator->() const { 107 assert (Scope && "Dereferencing invalid iterator is not allowed"); 108 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 109 return &Scope->Vars[VarIter - 1]; 110 } 111 VarDecl* operator*() const { 112 return *this->operator->(); 113 } 114 115 const_iterator& operator++() { 116 if (!Scope) 117 return *this; 118 119 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 120 --VarIter; 121 if (VarIter == 0) 122 *this = Scope->Prev; 123 return *this; 124 } 125 const_iterator operator++(int) { 126 const_iterator P = *this; 127 ++*this; 128 return P; 129 } 130 131 bool operator==(const const_iterator& rhs) const { 132 return Scope == rhs.Scope && VarIter == rhs.VarIter; 133 } 134 bool operator!=(const const_iterator& rhs) const { 135 return !(*this == rhs); 136 } 137 138 operator bool() const { 139 return *this != const_iterator(); 140 } 141 142 int distance(const_iterator L); 143 }; 144 145 friend class const_iterator; 146 147private: 148 /// Automatic variables in order of declaration. 149 AutomaticVarsTy Vars; 150 /// Iterator to variable in previous scope that was declared just before 151 /// begin of this scope. 152 const_iterator Prev; 153 154public: 155 /// Constructs empty scope linked to previous scope in specified place. 156 LocalScope(const_iterator P) 157 : Vars() 158 , Prev(P) {} 159 160 /// Begin of scope in direction of CFG building (backwards). 161 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 162 163 void addVar(VarDecl* VD) { 164 Vars.push_back(VD); 165 } 166}; 167 168/// distance - Calculates distance from this to L. L must be reachable from this 169/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 170/// number of scopes between this and L. 171int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 172 int D = 0; 173 const_iterator F = *this; 174 while (F.Scope != L.Scope) { 175 assert (F != const_iterator() 176 && "L iterator is not reachable from F iterator."); 177 D += F.VarIter; 178 F = F.Scope->Prev; 179 } 180 D += F.VarIter - L.VarIter; 181 return D; 182} 183 184/// BlockScopePosPair - Structure for specifying position in CFG during its 185/// build process. It consists of CFGBlock that specifies position in CFG graph 186/// and LocalScope::const_iterator that specifies position in LocalScope graph. 187struct BlockScopePosPair { 188 BlockScopePosPair() {} 189 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 190 : Block(B), ScopePos(S) {} 191 192 CFGBlock* Block; 193 LocalScope::const_iterator ScopePos; 194}; 195 196/// CFGBuilder - This class implements CFG construction from an AST. 197/// The builder is stateful: an instance of the builder should be used to only 198/// construct a single CFG. 199/// 200/// Example usage: 201/// 202/// CFGBuilder builder; 203/// CFG* cfg = builder.BuildAST(stmt1); 204/// 205/// CFG construction is done via a recursive walk of an AST. We actually parse 206/// the AST in reverse order so that the successor of a basic block is 207/// constructed prior to its predecessor. This allows us to nicely capture 208/// implicit fall-throughs without extra basic blocks. 209/// 210class CFGBuilder { 211 typedef BlockScopePosPair JumpTarget; 212 typedef BlockScopePosPair JumpSource; 213 214 ASTContext *Context; 215 llvm::OwningPtr<CFG> cfg; 216 217 CFGBlock* Block; 218 CFGBlock* Succ; 219 JumpTarget ContinueJumpTarget; 220 JumpTarget BreakJumpTarget; 221 CFGBlock* SwitchTerminatedBlock; 222 CFGBlock* DefaultCaseBlock; 223 CFGBlock* TryTerminatedBlock; 224 225 // Current position in local scope. 226 LocalScope::const_iterator ScopePos; 227 228 // LabelMap records the mapping from Label expressions to their jump targets. 229 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 230 LabelMapTy LabelMap; 231 232 // A list of blocks that end with a "goto" that must be backpatched to their 233 // resolved targets upon completion of CFG construction. 234 typedef std::vector<JumpSource> BackpatchBlocksTy; 235 BackpatchBlocksTy BackpatchBlocks; 236 237 // A list of labels whose address has been taken (for indirect gotos). 238 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 239 LabelSetTy AddressTakenLabels; 240 241 bool badCFG; 242 CFG::BuildOptions BuildOpts; 243 244public: 245 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 246 Block(NULL), Succ(NULL), 247 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 248 TryTerminatedBlock(NULL), badCFG(false) {} 249 250 // buildCFG - Used by external clients to construct the CFG. 251 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 252 CFG::BuildOptions BO); 253 254private: 255 // Visitors to walk an AST and construct the CFG. 256 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 257 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 258 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 259 CFGBlock *VisitBreakStmt(BreakStmt *B); 260 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 261 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 262 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 263 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 264 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 265 CFGBlock *VisitCaseStmt(CaseStmt *C); 266 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 267 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 268 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 269 CFGBlock *VisitContinueStmt(ContinueStmt *C); 270 CFGBlock *VisitDeclStmt(DeclStmt *DS); 271 CFGBlock *VisitDeclSubExpr(Decl* D); 272 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 273 CFGBlock *VisitDoStmt(DoStmt *D); 274 CFGBlock *VisitForStmt(ForStmt *F); 275 CFGBlock *VisitGotoStmt(GotoStmt* G); 276 CFGBlock *VisitIfStmt(IfStmt *I); 277 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 278 CFGBlock *VisitLabelStmt(LabelStmt *L); 279 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 280 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 281 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 282 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 283 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 284 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 285 CFGBlock *VisitReturnStmt(ReturnStmt* R); 286 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 287 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 288 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 289 CFGBlock *VisitWhileStmt(WhileStmt *W); 290 291 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 292 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 293 CFGBlock *VisitChildren(Stmt* S); 294 295 // NYS == Not Yet Supported 296 CFGBlock* NYS() { 297 badCFG = true; 298 return Block; 299 } 300 301 void autoCreateBlock() { if (!Block) Block = createBlock(); } 302 CFGBlock *createBlock(bool add_successor = true); 303 304 CFGBlock *addStmt(Stmt *S) { 305 return Visit(S, AddStmtChoice::AlwaysAdd); 306 } 307 CFGBlock *addInitializer(CXXBaseOrMemberInitializer *I); 308 void addAutomaticObjDtors(LocalScope::const_iterator B, 309 LocalScope::const_iterator E, Stmt* S); 310 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 311 312 // Local scopes creation. 313 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 314 315 void addLocalScopeForStmt(Stmt* S); 316 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 317 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 318 319 void addLocalScopeAndDtors(Stmt* S); 320 321 // Interface to CFGBlock - adding CFGElements. 322 void AppendStmt(CFGBlock *B, Stmt *S, 323 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 324 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 325 } 326 void appendInitializer(CFGBlock *B, CXXBaseOrMemberInitializer *I) { 327 B->appendInitializer(I, cfg->getBumpVectorContext()); 328 } 329 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 330 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 331 } 332 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 333 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 334 } 335 336 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 337 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 338 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 339 LocalScope::const_iterator E, Stmt* S); 340 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 341 LocalScope::const_iterator B, LocalScope::const_iterator E); 342 343 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 344 B->addSuccessor(S, cfg->getBumpVectorContext()); 345 } 346 347 /// TryResult - a class representing a variant over the values 348 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 349 /// and is used by the CFGBuilder to decide if a branch condition 350 /// can be decided up front during CFG construction. 351 class TryResult { 352 int X; 353 public: 354 TryResult(bool b) : X(b ? 1 : 0) {} 355 TryResult() : X(-1) {} 356 357 bool isTrue() const { return X == 1; } 358 bool isFalse() const { return X == 0; } 359 bool isKnown() const { return X >= 0; } 360 void negate() { 361 assert(isKnown()); 362 X ^= 0x1; 363 } 364 }; 365 366 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 367 /// if we can evaluate to a known value, otherwise return -1. 368 TryResult TryEvaluateBool(Expr *S) { 369 if (!BuildOpts.PruneTriviallyFalseEdges) 370 return TryResult(); 371 372 Expr::EvalResult Result; 373 if (!S->isTypeDependent() && !S->isValueDependent() && 374 S->Evaluate(Result, *Context) && Result.Val.isInt()) 375 return Result.Val.getInt().getBoolValue(); 376 377 return TryResult(); 378 } 379}; 380 381// FIXME: Add support for dependent-sized array types in C++? 382// Does it even make sense to build a CFG for an uninstantiated template? 383static VariableArrayType* FindVA(Type* t) { 384 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 385 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 386 if (vat->getSizeExpr()) 387 return vat; 388 389 t = vt->getElementType().getTypePtr(); 390 } 391 392 return 0; 393} 394 395/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 396/// arbitrary statement. Examples include a single expression or a function 397/// body (compound statement). The ownership of the returned CFG is 398/// transferred to the caller. If CFG construction fails, this method returns 399/// NULL. 400CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 401 CFG::BuildOptions BO) { 402 403 Context = C; 404 assert(cfg.get()); 405 if (!Statement) 406 return NULL; 407 408 BuildOpts = BO; 409 410 // Create an empty block that will serve as the exit block for the CFG. Since 411 // this is the first block added to the CFG, it will be implicitly registered 412 // as the exit block. 413 Succ = createBlock(); 414 assert(Succ == &cfg->getExit()); 415 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 416 417 if (BuildOpts.AddImplicitDtors) 418 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 419 addImplicitDtorsForDestructor(DD); 420 421 // Visit the statements and create the CFG. 422 CFGBlock *B = addStmt(Statement); 423 424 if (badCFG) 425 return NULL; 426 427 // For C++ constructor add initializers to CFG. 428 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 429 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 430 E = CD->init_rend(); I != E; ++I) { 431 B = addInitializer(*I); 432 if (badCFG) 433 return NULL; 434 } 435 } 436 437 if (B) 438 Succ = B; 439 440 // Backpatch the gotos whose label -> block mappings we didn't know when we 441 // encountered them. 442 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 443 E = BackpatchBlocks.end(); I != E; ++I ) { 444 445 CFGBlock* B = I->Block; 446 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 447 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 448 449 // If there is no target for the goto, then we are looking at an 450 // incomplete AST. Handle this by not registering a successor. 451 if (LI == LabelMap.end()) continue; 452 453 JumpTarget JT = LI->second; 454 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 455 AddSuccessor(B, JT.Block); 456 } 457 458 // Add successors to the Indirect Goto Dispatch block (if we have one). 459 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 460 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 461 E = AddressTakenLabels.end(); I != E; ++I ) { 462 463 // Lookup the target block. 464 LabelMapTy::iterator LI = LabelMap.find(*I); 465 466 // If there is no target block that contains label, then we are looking 467 // at an incomplete AST. Handle this by not registering a successor. 468 if (LI == LabelMap.end()) continue; 469 470 AddSuccessor(B, LI->second.Block); 471 } 472 473 // Create an empty entry block that has no predecessors. 474 cfg->setEntry(createBlock()); 475 476 return cfg.take(); 477} 478 479/// createBlock - Used to lazily create blocks that are connected 480/// to the current (global) succcessor. 481CFGBlock* CFGBuilder::createBlock(bool add_successor) { 482 CFGBlock* B = cfg->createBlock(); 483 if (add_successor && Succ) 484 AddSuccessor(B, Succ); 485 return B; 486} 487 488/// addInitializer - Add C++ base or member initializer element to CFG. 489CFGBlock *CFGBuilder::addInitializer(CXXBaseOrMemberInitializer *I) { 490 if (!BuildOpts.AddInitializers) 491 return Block; 492 493 autoCreateBlock(); 494 appendInitializer(Block, I); 495 496 if (Expr *Init = I->getInit()) { 497 AddStmtChoice::Kind K = AddStmtChoice::NotAlwaysAdd; 498 if (FieldDecl *FD = I->getMember()) 499 if (FD->getType()->isReferenceType()) 500 K = AddStmtChoice::AsLValueNotAlwaysAdd; 501 502 return Visit(Init, AddStmtChoice(K)); 503 } 504 505 return Block; 506} 507 508/// addAutomaticObjDtors - Add to current block automatic objects destructors 509/// for objects in range of local scope positions. Use S as trigger statement 510/// for destructors. 511void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 512 LocalScope::const_iterator E, Stmt* S) { 513 if (!BuildOpts.AddImplicitDtors) 514 return; 515 516 if (B == E) 517 return; 518 519 autoCreateBlock(); 520 appendAutomaticObjDtors(Block, B, E, S); 521} 522 523/// addImplicitDtorsForDestructor - Add implicit destructors generated for 524/// base and member objects in destructor. 525void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 526 assert (BuildOpts.AddImplicitDtors 527 && "Can be called only when dtors should be added"); 528 const CXXRecordDecl *RD = DD->getParent(); 529 530 // At the end destroy virtual base objects. 531 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 532 VE = RD->vbases_end(); VI != VE; ++VI) { 533 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 534 if (!CD->hasTrivialDestructor()) { 535 autoCreateBlock(); 536 appendBaseDtor(Block, VI); 537 } 538 } 539 540 // Before virtual bases destroy direct base objects. 541 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 542 BE = RD->bases_end(); BI != BE; ++BI) { 543 if (!BI->isVirtual()) { 544 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 545 if (!CD->hasTrivialDestructor()) { 546 autoCreateBlock(); 547 appendBaseDtor(Block, BI); 548 } 549 } 550 } 551 552 // First destroy member objects. 553 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 554 FE = RD->field_end(); FI != FE; ++FI) { 555 // Check for constant size array. Set type to array element type. 556 QualType QT = FI->getType(); 557 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 558 if (AT->getSize() == 0) 559 continue; 560 QT = AT->getElementType(); 561 } 562 563 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 564 if (!CD->hasTrivialDestructor()) { 565 autoCreateBlock(); 566 appendMemberDtor(Block, *FI); 567 } 568 } 569} 570 571/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 572/// way return valid LocalScope object. 573LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 574 if (!Scope) { 575 Scope = cfg->getAllocator().Allocate<LocalScope>(); 576 new (Scope) LocalScope(ScopePos); 577 } 578 return Scope; 579} 580 581/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 582/// that should create implicit scope (e.g. if/else substatements). 583void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 584 if (!BuildOpts.AddImplicitDtors) 585 return; 586 587 LocalScope *Scope = 0; 588 589 // For compound statement we will be creating explicit scope. 590 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 591 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 592 ; BI != BE; ++BI) { 593 Stmt* SI = *BI; 594 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 595 SI = LS->getSubStmt(); 596 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 597 Scope = addLocalScopeForDeclStmt(DS, Scope); 598 } 599 return; 600 } 601 602 // For any other statement scope will be implicit and as such will be 603 // interesting only for DeclStmt. 604 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 605 S = LS->getSubStmt(); 606 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 607 addLocalScopeForDeclStmt(DS); 608} 609 610/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 611/// reuse Scope if not NULL. 612LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 613 LocalScope* Scope) { 614 if (!BuildOpts.AddImplicitDtors) 615 return Scope; 616 617 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 618 ; DI != DE; ++DI) { 619 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 620 Scope = addLocalScopeForVarDecl(VD, Scope); 621 } 622 return Scope; 623} 624 625/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 626/// create add scope for automatic objects and temporary objects bound to 627/// const reference. Will reuse Scope if not NULL. 628LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 629 LocalScope* Scope) { 630 if (!BuildOpts.AddImplicitDtors) 631 return Scope; 632 633 // Check if variable is local. 634 switch (VD->getStorageClass()) { 635 case SC_None: 636 case SC_Auto: 637 case SC_Register: 638 break; 639 default: return Scope; 640 } 641 642 // Check for const references bound to temporary. Set type to pointee. 643 QualType QT = VD->getType(); 644 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 645 QT = RT->getPointeeType(); 646 if (!QT.isConstQualified()) 647 return Scope; 648 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 649 return Scope; 650 } 651 652 // Check for constant size array. Set type to array element type. 653 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 654 if (AT->getSize() == 0) 655 return Scope; 656 QT = AT->getElementType(); 657 } 658 659 // Check if type is a C++ class with non-trivial destructor. 660 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 661 if (!CD->hasTrivialDestructor()) { 662 // Add the variable to scope 663 Scope = createOrReuseLocalScope(Scope); 664 Scope->addVar(VD); 665 ScopePos = Scope->begin(); 666 } 667 return Scope; 668} 669 670/// addLocalScopeAndDtors - For given statement add local scope for it and 671/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 672void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 673 if (!BuildOpts.AddImplicitDtors) 674 return; 675 676 LocalScope::const_iterator scopeBeginPos = ScopePos; 677 addLocalScopeForStmt(S); 678 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 679} 680 681/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 682/// automatic storage duration to CFGBlock's elements vector. Insertion will be 683/// performed in place specified with iterator. 684void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 685 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 686 BumpVectorContext& C = cfg->getBumpVectorContext(); 687 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 688 while (B != E) 689 I = Blk->insertAutomaticObjDtor(I, *B++, S); 690} 691 692/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 693/// automatic storage duration to CFGBlock's elements vector. Elements will be 694/// appended to physical end of the vector which happens to be logical 695/// beginning. 696void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 697 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 698 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 699} 700 701/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 702/// variables with automatic storage duration to CFGBlock's elements vector. 703/// Elements will be prepended to physical beginning of the vector which 704/// happens to be logical end. Use blocks terminator as statement that specifies 705/// destructors call site. 706void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 707 LocalScope::const_iterator B, LocalScope::const_iterator E) { 708 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 709} 710 711/// Visit - Walk the subtree of a statement and add extra 712/// blocks for ternary operators, &&, and ||. We also process "," and 713/// DeclStmts (which may contain nested control-flow). 714CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 715tryAgain: 716 if (!S) { 717 badCFG = true; 718 return 0; 719 } 720 switch (S->getStmtClass()) { 721 default: 722 return VisitStmt(S, asc); 723 724 case Stmt::AddrLabelExprClass: 725 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 726 727 case Stmt::BinaryOperatorClass: 728 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 729 730 case Stmt::BlockExprClass: 731 return VisitBlockExpr(cast<BlockExpr>(S), asc); 732 733 case Stmt::BreakStmtClass: 734 return VisitBreakStmt(cast<BreakStmt>(S)); 735 736 case Stmt::CallExprClass: 737 case Stmt::CXXOperatorCallExprClass: 738 return VisitCallExpr(cast<CallExpr>(S), asc); 739 740 case Stmt::CaseStmtClass: 741 return VisitCaseStmt(cast<CaseStmt>(S)); 742 743 case Stmt::ChooseExprClass: 744 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 745 746 case Stmt::CompoundStmtClass: 747 return VisitCompoundStmt(cast<CompoundStmt>(S)); 748 749 case Stmt::ConditionalOperatorClass: 750 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 751 752 case Stmt::ContinueStmtClass: 753 return VisitContinueStmt(cast<ContinueStmt>(S)); 754 755 case Stmt::CXXCatchStmtClass: 756 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 757 758 case Stmt::CXXExprWithTemporariesClass: { 759 // FIXME: Handle temporaries. For now, just visit the subexpression 760 // so we don't artificially create extra blocks. 761 return Visit(cast<CXXExprWithTemporaries>(S)->getSubExpr(), asc); 762 } 763 764 case Stmt::CXXMemberCallExprClass: 765 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 766 767 case Stmt::CXXThrowExprClass: 768 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 769 770 case Stmt::CXXTryStmtClass: 771 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 772 773 case Stmt::DeclStmtClass: 774 return VisitDeclStmt(cast<DeclStmt>(S)); 775 776 case Stmt::DefaultStmtClass: 777 return VisitDefaultStmt(cast<DefaultStmt>(S)); 778 779 case Stmt::DoStmtClass: 780 return VisitDoStmt(cast<DoStmt>(S)); 781 782 case Stmt::ForStmtClass: 783 return VisitForStmt(cast<ForStmt>(S)); 784 785 case Stmt::GotoStmtClass: 786 return VisitGotoStmt(cast<GotoStmt>(S)); 787 788 case Stmt::IfStmtClass: 789 return VisitIfStmt(cast<IfStmt>(S)); 790 791 case Stmt::IndirectGotoStmtClass: 792 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 793 794 case Stmt::LabelStmtClass: 795 return VisitLabelStmt(cast<LabelStmt>(S)); 796 797 case Stmt::MemberExprClass: 798 return VisitMemberExpr(cast<MemberExpr>(S), asc); 799 800 case Stmt::ObjCAtCatchStmtClass: 801 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 802 803 case Stmt::ObjCAtSynchronizedStmtClass: 804 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 805 806 case Stmt::ObjCAtThrowStmtClass: 807 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 808 809 case Stmt::ObjCAtTryStmtClass: 810 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 811 812 case Stmt::ObjCForCollectionStmtClass: 813 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 814 815 case Stmt::ParenExprClass: 816 S = cast<ParenExpr>(S)->getSubExpr(); 817 goto tryAgain; 818 819 case Stmt::NullStmtClass: 820 return Block; 821 822 case Stmt::ReturnStmtClass: 823 return VisitReturnStmt(cast<ReturnStmt>(S)); 824 825 case Stmt::SizeOfAlignOfExprClass: 826 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 827 828 case Stmt::StmtExprClass: 829 return VisitStmtExpr(cast<StmtExpr>(S), asc); 830 831 case Stmt::SwitchStmtClass: 832 return VisitSwitchStmt(cast<SwitchStmt>(S)); 833 834 case Stmt::WhileStmtClass: 835 return VisitWhileStmt(cast<WhileStmt>(S)); 836 } 837} 838 839CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 840 if (asc.alwaysAdd()) { 841 autoCreateBlock(); 842 AppendStmt(Block, S, asc); 843 } 844 845 return VisitChildren(S); 846} 847 848/// VisitChildren - Visit the children of a Stmt. 849CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 850 CFGBlock *B = Block; 851 for (Stmt::child_iterator I = Terminator->child_begin(), 852 E = Terminator->child_end(); I != E; ++I) { 853 if (*I) B = Visit(*I); 854 } 855 return B; 856} 857 858CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 859 AddStmtChoice asc) { 860 AddressTakenLabels.insert(A->getLabel()); 861 862 if (asc.alwaysAdd()) { 863 autoCreateBlock(); 864 AppendStmt(Block, A, asc); 865 } 866 867 return Block; 868} 869 870CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 871 AddStmtChoice asc) { 872 if (B->isLogicalOp()) { // && or || 873 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 874 AppendStmt(ConfluenceBlock, B, asc); 875 876 if (badCFG) 877 return 0; 878 879 // create the block evaluating the LHS 880 CFGBlock* LHSBlock = createBlock(false); 881 LHSBlock->setTerminator(B); 882 883 // create the block evaluating the RHS 884 Succ = ConfluenceBlock; 885 Block = NULL; 886 CFGBlock* RHSBlock = addStmt(B->getRHS()); 887 888 if (RHSBlock) { 889 if (badCFG) 890 return 0; 891 } 892 else { 893 // Create an empty block for cases where the RHS doesn't require 894 // any explicit statements in the CFG. 895 RHSBlock = createBlock(); 896 } 897 898 // See if this is a known constant. 899 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 900 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 901 KnownVal.negate(); 902 903 // Now link the LHSBlock with RHSBlock. 904 if (B->getOpcode() == BO_LOr) { 905 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 906 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 907 } else { 908 assert(B->getOpcode() == BO_LAnd); 909 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 910 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 911 } 912 913 // Generate the blocks for evaluating the LHS. 914 Block = LHSBlock; 915 return addStmt(B->getLHS()); 916 } 917 else if (B->getOpcode() == BO_Comma) { // , 918 autoCreateBlock(); 919 AppendStmt(Block, B, asc); 920 addStmt(B->getRHS()); 921 return addStmt(B->getLHS()); 922 } 923 else if (B->isAssignmentOp()) { 924 if (asc.alwaysAdd()) { 925 autoCreateBlock(); 926 AppendStmt(Block, B, asc); 927 } 928 929 Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 930 return Visit(B->getRHS()); 931 } 932 933 if (asc.alwaysAdd()) { 934 autoCreateBlock(); 935 AppendStmt(Block, B, asc); 936 } 937 938 Visit(B->getRHS()); 939 return Visit(B->getLHS()); 940} 941 942CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 943 if (asc.alwaysAdd()) { 944 autoCreateBlock(); 945 AppendStmt(Block, E, asc); 946 } 947 return Block; 948} 949 950CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 951 // "break" is a control-flow statement. Thus we stop processing the current 952 // block. 953 if (badCFG) 954 return 0; 955 956 // Now create a new block that ends with the break statement. 957 Block = createBlock(false); 958 Block->setTerminator(B); 959 960 // If there is no target for the break, then we are looking at an incomplete 961 // AST. This means that the CFG cannot be constructed. 962 if (BreakJumpTarget.Block) { 963 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 964 AddSuccessor(Block, BreakJumpTarget.Block); 965 } else 966 badCFG = true; 967 968 969 return Block; 970} 971 972static bool CanThrow(Expr *E) { 973 QualType Ty = E->getType(); 974 if (Ty->isFunctionPointerType()) 975 Ty = Ty->getAs<PointerType>()->getPointeeType(); 976 else if (Ty->isBlockPointerType()) 977 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 978 979 const FunctionType *FT = Ty->getAs<FunctionType>(); 980 if (FT) { 981 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 982 if (Proto->hasEmptyExceptionSpec()) 983 return false; 984 } 985 return true; 986} 987 988CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 989 // If this is a call to a no-return function, this stops the block here. 990 bool NoReturn = false; 991 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 992 NoReturn = true; 993 } 994 995 bool AddEHEdge = false; 996 997 // Languages without exceptions are assumed to not throw. 998 if (Context->getLangOptions().Exceptions) { 999 if (BuildOpts.AddEHEdges) 1000 AddEHEdge = true; 1001 } 1002 1003 if (FunctionDecl *FD = C->getDirectCallee()) { 1004 if (FD->hasAttr<NoReturnAttr>()) 1005 NoReturn = true; 1006 if (FD->hasAttr<NoThrowAttr>()) 1007 AddEHEdge = false; 1008 } 1009 1010 if (!CanThrow(C->getCallee())) 1011 AddEHEdge = false; 1012 1013 if (!NoReturn && !AddEHEdge) { 1014 if (asc.asLValue()) 1015 return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue); 1016 else 1017 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 1018 } 1019 1020 if (Block) { 1021 Succ = Block; 1022 if (badCFG) 1023 return 0; 1024 } 1025 1026 Block = createBlock(!NoReturn); 1027 AppendStmt(Block, C, asc); 1028 1029 if (NoReturn) { 1030 // Wire this to the exit block directly. 1031 AddSuccessor(Block, &cfg->getExit()); 1032 } 1033 if (AddEHEdge) { 1034 // Add exceptional edges. 1035 if (TryTerminatedBlock) 1036 AddSuccessor(Block, TryTerminatedBlock); 1037 else 1038 AddSuccessor(Block, &cfg->getExit()); 1039 } 1040 1041 return VisitChildren(C); 1042} 1043 1044CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1045 AddStmtChoice asc) { 1046 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1047 AppendStmt(ConfluenceBlock, C, asc); 1048 if (badCFG) 1049 return 0; 1050 1051 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1052 : AddStmtChoice::AlwaysAdd; 1053 1054 Succ = ConfluenceBlock; 1055 Block = NULL; 1056 CFGBlock* LHSBlock = Visit(C->getLHS(), asc); 1057 if (badCFG) 1058 return 0; 1059 1060 Succ = ConfluenceBlock; 1061 Block = NULL; 1062 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1063 if (badCFG) 1064 return 0; 1065 1066 Block = createBlock(false); 1067 // See if this is a known constant. 1068 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1069 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1070 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1071 Block->setTerminator(C); 1072 return addStmt(C->getCond()); 1073} 1074 1075 1076CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1077 addLocalScopeAndDtors(C); 1078 CFGBlock* LastBlock = Block; 1079 1080 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1081 I != E; ++I ) { 1082 // If we hit a segment of code just containing ';' (NullStmts), we can 1083 // get a null block back. In such cases, just use the LastBlock 1084 if (CFGBlock *newBlock = addStmt(*I)) 1085 LastBlock = newBlock; 1086 1087 if (badCFG) 1088 return NULL; 1089 } 1090 1091 return LastBlock; 1092} 1093 1094CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1095 AddStmtChoice asc) { 1096 // Create the confluence block that will "merge" the results of the ternary 1097 // expression. 1098 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1099 AppendStmt(ConfluenceBlock, C, asc); 1100 if (badCFG) 1101 return 0; 1102 1103 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1104 : AddStmtChoice::AlwaysAdd; 1105 1106 // Create a block for the LHS expression if there is an LHS expression. A 1107 // GCC extension allows LHS to be NULL, causing the condition to be the 1108 // value that is returned instead. 1109 // e.g: x ?: y is shorthand for: x ? x : y; 1110 Succ = ConfluenceBlock; 1111 Block = NULL; 1112 CFGBlock* LHSBlock = NULL; 1113 if (C->getLHS()) { 1114 LHSBlock = Visit(C->getLHS(), asc); 1115 if (badCFG) 1116 return 0; 1117 Block = NULL; 1118 } 1119 1120 // Create the block for the RHS expression. 1121 Succ = ConfluenceBlock; 1122 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1123 if (badCFG) 1124 return 0; 1125 1126 // Create the block that will contain the condition. 1127 Block = createBlock(false); 1128 1129 // See if this is a known constant. 1130 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1131 if (LHSBlock) { 1132 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1133 } else { 1134 if (KnownVal.isFalse()) { 1135 // If we know the condition is false, add NULL as the successor for 1136 // the block containing the condition. In this case, the confluence 1137 // block will have just one predecessor. 1138 AddSuccessor(Block, 0); 1139 assert(ConfluenceBlock->pred_size() == 1); 1140 } else { 1141 // If we have no LHS expression, add the ConfluenceBlock as a direct 1142 // successor for the block containing the condition. Moreover, we need to 1143 // reverse the order of the predecessors in the ConfluenceBlock because 1144 // the RHSBlock will have been added to the succcessors already, and we 1145 // want the first predecessor to the the block containing the expression 1146 // for the case when the ternary expression evaluates to true. 1147 AddSuccessor(Block, ConfluenceBlock); 1148 assert(ConfluenceBlock->pred_size() == 2); 1149 std::reverse(ConfluenceBlock->pred_begin(), 1150 ConfluenceBlock->pred_end()); 1151 } 1152 } 1153 1154 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1155 Block->setTerminator(C); 1156 return addStmt(C->getCond()); 1157} 1158 1159CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1160 autoCreateBlock(); 1161 1162 if (DS->isSingleDecl()) { 1163 AppendStmt(Block, DS); 1164 return VisitDeclSubExpr(DS->getSingleDecl()); 1165 } 1166 1167 CFGBlock *B = 0; 1168 1169 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1170 typedef llvm::SmallVector<Decl*,10> BufTy; 1171 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1172 1173 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1174 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1175 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1176 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1177 1178 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1179 // automatically freed with the CFG. 1180 DeclGroupRef DG(*I); 1181 Decl *D = *I; 1182 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1183 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1184 1185 // Append the fake DeclStmt to block. 1186 AppendStmt(Block, DSNew); 1187 B = VisitDeclSubExpr(D); 1188 } 1189 1190 return B; 1191} 1192 1193/// VisitDeclSubExpr - Utility method to add block-level expressions for 1194/// initializers in Decls. 1195CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 1196 assert(Block); 1197 1198 VarDecl *VD = dyn_cast<VarDecl>(D); 1199 1200 if (!VD) 1201 return Block; 1202 1203 Expr *Init = VD->getInit(); 1204 1205 if (Init) { 1206 AddStmtChoice::Kind k = 1207 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 1208 : AddStmtChoice::NotAlwaysAdd; 1209 Visit(Init, AddStmtChoice(k)); 1210 } 1211 1212 // If the type of VD is a VLA, then we must process its size expressions. 1213 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1214 VA = FindVA(VA->getElementType().getTypePtr())) 1215 Block = addStmt(VA->getSizeExpr()); 1216 1217 // Remove variable from local scope. 1218 if (ScopePos && VD == *ScopePos) 1219 ++ScopePos; 1220 1221 return Block; 1222} 1223 1224CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1225 // We may see an if statement in the middle of a basic block, or it may be the 1226 // first statement we are processing. In either case, we create a new basic 1227 // block. First, we create the blocks for the then...else statements, and 1228 // then we create the block containing the if statement. If we were in the 1229 // middle of a block, we stop processing that block. That block is then the 1230 // implicit successor for the "then" and "else" clauses. 1231 1232 // Save local scope position because in case of condition variable ScopePos 1233 // won't be restored when traversing AST. 1234 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1235 1236 // Create local scope for possible condition variable. 1237 // Store scope position. Add implicit destructor. 1238 if (VarDecl* VD = I->getConditionVariable()) { 1239 LocalScope::const_iterator BeginScopePos = ScopePos; 1240 addLocalScopeForVarDecl(VD); 1241 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1242 } 1243 1244 // The block we were proccessing is now finished. Make it the successor 1245 // block. 1246 if (Block) { 1247 Succ = Block; 1248 if (badCFG) 1249 return 0; 1250 } 1251 1252 // Process the false branch. 1253 CFGBlock* ElseBlock = Succ; 1254 1255 if (Stmt* Else = I->getElse()) { 1256 SaveAndRestore<CFGBlock*> sv(Succ); 1257 1258 // NULL out Block so that the recursive call to Visit will 1259 // create a new basic block. 1260 Block = NULL; 1261 1262 // If branch is not a compound statement create implicit scope 1263 // and add destructors. 1264 if (!isa<CompoundStmt>(Else)) 1265 addLocalScopeAndDtors(Else); 1266 1267 ElseBlock = addStmt(Else); 1268 1269 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1270 ElseBlock = sv.get(); 1271 else if (Block) { 1272 if (badCFG) 1273 return 0; 1274 } 1275 } 1276 1277 // Process the true branch. 1278 CFGBlock* ThenBlock; 1279 { 1280 Stmt* Then = I->getThen(); 1281 assert(Then); 1282 SaveAndRestore<CFGBlock*> sv(Succ); 1283 Block = NULL; 1284 1285 // If branch is not a compound statement create implicit scope 1286 // and add destructors. 1287 if (!isa<CompoundStmt>(Then)) 1288 addLocalScopeAndDtors(Then); 1289 1290 ThenBlock = addStmt(Then); 1291 1292 if (!ThenBlock) { 1293 // We can reach here if the "then" body has all NullStmts. 1294 // Create an empty block so we can distinguish between true and false 1295 // branches in path-sensitive analyses. 1296 ThenBlock = createBlock(false); 1297 AddSuccessor(ThenBlock, sv.get()); 1298 } else if (Block) { 1299 if (badCFG) 1300 return 0; 1301 } 1302 } 1303 1304 // Now create a new block containing the if statement. 1305 Block = createBlock(false); 1306 1307 // Set the terminator of the new block to the If statement. 1308 Block->setTerminator(I); 1309 1310 // See if this is a known constant. 1311 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1312 1313 // Now add the successors. 1314 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1315 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1316 1317 // Add the condition as the last statement in the new block. This may create 1318 // new blocks as the condition may contain control-flow. Any newly created 1319 // blocks will be pointed to be "Block". 1320 Block = addStmt(I->getCond()); 1321 1322 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1323 // and the condition variable initialization to the CFG. 1324 if (VarDecl *VD = I->getConditionVariable()) { 1325 if (Expr *Init = VD->getInit()) { 1326 autoCreateBlock(); 1327 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1328 addStmt(Init); 1329 } 1330 } 1331 1332 return Block; 1333} 1334 1335 1336CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1337 // If we were in the middle of a block we stop processing that block. 1338 // 1339 // NOTE: If a "return" appears in the middle of a block, this means that the 1340 // code afterwards is DEAD (unreachable). We still keep a basic block 1341 // for that code; a simple "mark-and-sweep" from the entry block will be 1342 // able to report such dead blocks. 1343 1344 // Create the new block. 1345 Block = createBlock(false); 1346 1347 // The Exit block is the only successor. 1348 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1349 AddSuccessor(Block, &cfg->getExit()); 1350 1351 // Add the return statement to the block. This may create new blocks if R 1352 // contains control-flow (short-circuit operations). 1353 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1354} 1355 1356CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1357 // Get the block of the labeled statement. Add it to our map. 1358 addStmt(L->getSubStmt()); 1359 CFGBlock* LabelBlock = Block; 1360 1361 if (!LabelBlock) // This can happen when the body is empty, i.e. 1362 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1363 1364 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1365 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1366 1367 // Labels partition blocks, so this is the end of the basic block we were 1368 // processing (L is the block's label). Because this is label (and we have 1369 // already processed the substatement) there is no extra control-flow to worry 1370 // about. 1371 LabelBlock->setLabel(L); 1372 if (badCFG) 1373 return 0; 1374 1375 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1376 Block = NULL; 1377 1378 // This block is now the implicit successor of other blocks. 1379 Succ = LabelBlock; 1380 1381 return LabelBlock; 1382} 1383 1384CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1385 // Goto is a control-flow statement. Thus we stop processing the current 1386 // block and create a new one. 1387 1388 Block = createBlock(false); 1389 Block->setTerminator(G); 1390 1391 // If we already know the mapping to the label block add the successor now. 1392 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1393 1394 if (I == LabelMap.end()) 1395 // We will need to backpatch this block later. 1396 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1397 else { 1398 JumpTarget JT = I->second; 1399 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1400 AddSuccessor(Block, JT.Block); 1401 } 1402 1403 return Block; 1404} 1405 1406CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1407 CFGBlock* LoopSuccessor = NULL; 1408 1409 // Save local scope position because in case of condition variable ScopePos 1410 // won't be restored when traversing AST. 1411 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1412 1413 // Create local scope for init statement and possible condition variable. 1414 // Add destructor for init statement and condition variable. 1415 // Store scope position for continue statement. 1416 if (Stmt* Init = F->getInit()) 1417 addLocalScopeForStmt(Init); 1418 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1419 1420 if (VarDecl* VD = F->getConditionVariable()) 1421 addLocalScopeForVarDecl(VD); 1422 LocalScope::const_iterator ContinueScopePos = ScopePos; 1423 1424 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1425 1426 // "for" is a control-flow statement. Thus we stop processing the current 1427 // block. 1428 if (Block) { 1429 if (badCFG) 1430 return 0; 1431 LoopSuccessor = Block; 1432 } else 1433 LoopSuccessor = Succ; 1434 1435 // Save the current value for the break targets. 1436 // All breaks should go to the code following the loop. 1437 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1438 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1439 1440 // Because of short-circuit evaluation, the condition of the loop can span 1441 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1442 // evaluate the condition. 1443 CFGBlock* ExitConditionBlock = createBlock(false); 1444 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1445 1446 // Set the terminator for the "exit" condition block. 1447 ExitConditionBlock->setTerminator(F); 1448 1449 // Now add the actual condition to the condition block. Because the condition 1450 // itself may contain control-flow, new blocks may be created. 1451 if (Stmt* C = F->getCond()) { 1452 Block = ExitConditionBlock; 1453 EntryConditionBlock = addStmt(C); 1454 assert(Block == EntryConditionBlock || 1455 (Block == 0 && EntryConditionBlock == Succ)); 1456 1457 // If this block contains a condition variable, add both the condition 1458 // variable and initializer to the CFG. 1459 if (VarDecl *VD = F->getConditionVariable()) { 1460 if (Expr *Init = VD->getInit()) { 1461 autoCreateBlock(); 1462 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1463 EntryConditionBlock = addStmt(Init); 1464 assert(Block == EntryConditionBlock); 1465 } 1466 } 1467 1468 if (Block) { 1469 if (badCFG) 1470 return 0; 1471 } 1472 } 1473 1474 // The condition block is the implicit successor for the loop body as well as 1475 // any code above the loop. 1476 Succ = EntryConditionBlock; 1477 1478 // See if this is a known constant. 1479 TryResult KnownVal(true); 1480 1481 if (F->getCond()) 1482 KnownVal = TryEvaluateBool(F->getCond()); 1483 1484 // Now create the loop body. 1485 { 1486 assert(F->getBody()); 1487 1488 // Save the current values for Block, Succ, and continue targets. 1489 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1490 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1491 1492 // Create a new block to contain the (bottom) of the loop body. 1493 Block = NULL; 1494 1495 // Loop body should end with destructor of Condition variable (if any). 1496 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1497 1498 if (Stmt* I = F->getInc()) { 1499 // Generate increment code in its own basic block. This is the target of 1500 // continue statements. 1501 Succ = addStmt(I); 1502 } else { 1503 // No increment code. Create a special, empty, block that is used as the 1504 // target block for "looping back" to the start of the loop. 1505 assert(Succ == EntryConditionBlock); 1506 Succ = Block ? Block : createBlock(); 1507 } 1508 1509 // Finish up the increment (or empty) block if it hasn't been already. 1510 if (Block) { 1511 assert(Block == Succ); 1512 if (badCFG) 1513 return 0; 1514 Block = 0; 1515 } 1516 1517 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1518 1519 // The starting block for the loop increment is the block that should 1520 // represent the 'loop target' for looping back to the start of the loop. 1521 ContinueJumpTarget.Block->setLoopTarget(F); 1522 1523 // If body is not a compound statement create implicit scope 1524 // and add destructors. 1525 if (!isa<CompoundStmt>(F->getBody())) 1526 addLocalScopeAndDtors(F->getBody()); 1527 1528 // Now populate the body block, and in the process create new blocks as we 1529 // walk the body of the loop. 1530 CFGBlock* BodyBlock = addStmt(F->getBody()); 1531 1532 if (!BodyBlock) 1533 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1534 else if (badCFG) 1535 return 0; 1536 1537 // This new body block is a successor to our "exit" condition block. 1538 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1539 } 1540 1541 // Link up the condition block with the code that follows the loop. (the 1542 // false branch). 1543 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1544 1545 // If the loop contains initialization, create a new block for those 1546 // statements. This block can also contain statements that precede the loop. 1547 if (Stmt* I = F->getInit()) { 1548 Block = createBlock(); 1549 return addStmt(I); 1550 } else { 1551 // There is no loop initialization. We are thus basically a while loop. 1552 // NULL out Block to force lazy block construction. 1553 Block = NULL; 1554 Succ = EntryConditionBlock; 1555 return EntryConditionBlock; 1556 } 1557} 1558 1559CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1560 if (asc.alwaysAdd()) { 1561 autoCreateBlock(); 1562 AppendStmt(Block, M, asc); 1563 } 1564 return Visit(M->getBase(), 1565 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1566 : AddStmtChoice::AsLValueNotAlwaysAdd); 1567} 1568 1569CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1570 // Objective-C fast enumeration 'for' statements: 1571 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1572 // 1573 // for ( Type newVariable in collection_expression ) { statements } 1574 // 1575 // becomes: 1576 // 1577 // prologue: 1578 // 1. collection_expression 1579 // T. jump to loop_entry 1580 // loop_entry: 1581 // 1. side-effects of element expression 1582 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1583 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1584 // TB: 1585 // statements 1586 // T. jump to loop_entry 1587 // FB: 1588 // what comes after 1589 // 1590 // and 1591 // 1592 // Type existingItem; 1593 // for ( existingItem in expression ) { statements } 1594 // 1595 // becomes: 1596 // 1597 // the same with newVariable replaced with existingItem; the binding works 1598 // the same except that for one ObjCForCollectionStmt::getElement() returns 1599 // a DeclStmt and the other returns a DeclRefExpr. 1600 // 1601 1602 CFGBlock* LoopSuccessor = 0; 1603 1604 if (Block) { 1605 if (badCFG) 1606 return 0; 1607 LoopSuccessor = Block; 1608 Block = 0; 1609 } else 1610 LoopSuccessor = Succ; 1611 1612 // Build the condition blocks. 1613 CFGBlock* ExitConditionBlock = createBlock(false); 1614 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1615 1616 // Set the terminator for the "exit" condition block. 1617 ExitConditionBlock->setTerminator(S); 1618 1619 // The last statement in the block should be the ObjCForCollectionStmt, which 1620 // performs the actual binding to 'element' and determines if there are any 1621 // more items in the collection. 1622 AppendStmt(ExitConditionBlock, S); 1623 Block = ExitConditionBlock; 1624 1625 // Walk the 'element' expression to see if there are any side-effects. We 1626 // generate new blocks as necesary. We DON'T add the statement by default to 1627 // the CFG unless it contains control-flow. 1628 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1629 if (Block) { 1630 if (badCFG) 1631 return 0; 1632 Block = 0; 1633 } 1634 1635 // The condition block is the implicit successor for the loop body as well as 1636 // any code above the loop. 1637 Succ = EntryConditionBlock; 1638 1639 // Now create the true branch. 1640 { 1641 // Save the current values for Succ, continue and break targets. 1642 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1643 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1644 save_break(BreakJumpTarget); 1645 1646 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1647 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1648 1649 CFGBlock* BodyBlock = addStmt(S->getBody()); 1650 1651 if (!BodyBlock) 1652 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1653 else if (Block) { 1654 if (badCFG) 1655 return 0; 1656 } 1657 1658 // This new body block is a successor to our "exit" condition block. 1659 AddSuccessor(ExitConditionBlock, BodyBlock); 1660 } 1661 1662 // Link up the condition block with the code that follows the loop. 1663 // (the false branch). 1664 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1665 1666 // Now create a prologue block to contain the collection expression. 1667 Block = createBlock(); 1668 return addStmt(S->getCollection()); 1669} 1670 1671CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1672 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1673 1674 // Inline the body. 1675 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1676 1677 // The sync body starts its own basic block. This makes it a little easier 1678 // for diagnostic clients. 1679 if (SyncBlock) { 1680 if (badCFG) 1681 return 0; 1682 1683 Block = 0; 1684 Succ = SyncBlock; 1685 } 1686 1687 // Add the @synchronized to the CFG. 1688 autoCreateBlock(); 1689 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1690 1691 // Inline the sync expression. 1692 return addStmt(S->getSynchExpr()); 1693} 1694 1695CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1696 // FIXME 1697 return NYS(); 1698} 1699 1700CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1701 CFGBlock* LoopSuccessor = NULL; 1702 1703 // Save local scope position because in case of condition variable ScopePos 1704 // won't be restored when traversing AST. 1705 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1706 1707 // Create local scope for possible condition variable. 1708 // Store scope position for continue statement. 1709 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1710 if (VarDecl* VD = W->getConditionVariable()) { 1711 addLocalScopeForVarDecl(VD); 1712 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1713 } 1714 1715 // "while" is a control-flow statement. Thus we stop processing the current 1716 // block. 1717 if (Block) { 1718 if (badCFG) 1719 return 0; 1720 LoopSuccessor = Block; 1721 } else 1722 LoopSuccessor = Succ; 1723 1724 // Because of short-circuit evaluation, the condition of the loop can span 1725 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1726 // evaluate the condition. 1727 CFGBlock* ExitConditionBlock = createBlock(false); 1728 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1729 1730 // Set the terminator for the "exit" condition block. 1731 ExitConditionBlock->setTerminator(W); 1732 1733 // Now add the actual condition to the condition block. Because the condition 1734 // itself may contain control-flow, new blocks may be created. Thus we update 1735 // "Succ" after adding the condition. 1736 if (Stmt* C = W->getCond()) { 1737 Block = ExitConditionBlock; 1738 EntryConditionBlock = addStmt(C); 1739 assert(Block == EntryConditionBlock); 1740 1741 // If this block contains a condition variable, add both the condition 1742 // variable and initializer to the CFG. 1743 if (VarDecl *VD = W->getConditionVariable()) { 1744 if (Expr *Init = VD->getInit()) { 1745 autoCreateBlock(); 1746 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1747 EntryConditionBlock = addStmt(Init); 1748 assert(Block == EntryConditionBlock); 1749 } 1750 } 1751 1752 if (Block) { 1753 if (badCFG) 1754 return 0; 1755 } 1756 } 1757 1758 // The condition block is the implicit successor for the loop body as well as 1759 // any code above the loop. 1760 Succ = EntryConditionBlock; 1761 1762 // See if this is a known constant. 1763 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1764 1765 // Process the loop body. 1766 { 1767 assert(W->getBody()); 1768 1769 // Save the current values for Block, Succ, and continue and break targets 1770 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1771 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1772 save_break(BreakJumpTarget); 1773 1774 // Create an empty block to represent the transition block for looping back 1775 // to the head of the loop. 1776 Block = 0; 1777 assert(Succ == EntryConditionBlock); 1778 Succ = createBlock(); 1779 Succ->setLoopTarget(W); 1780 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1781 1782 // All breaks should go to the code following the loop. 1783 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1784 1785 // NULL out Block to force lazy instantiation of blocks for the body. 1786 Block = NULL; 1787 1788 // Loop body should end with destructor of Condition variable (if any). 1789 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1790 1791 // If body is not a compound statement create implicit scope 1792 // and add destructors. 1793 if (!isa<CompoundStmt>(W->getBody())) 1794 addLocalScopeAndDtors(W->getBody()); 1795 1796 // Create the body. The returned block is the entry to the loop body. 1797 CFGBlock* BodyBlock = addStmt(W->getBody()); 1798 1799 if (!BodyBlock) 1800 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1801 else if (Block) { 1802 if (badCFG) 1803 return 0; 1804 } 1805 1806 // Add the loop body entry as a successor to the condition. 1807 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1808 } 1809 1810 // Link up the condition block with the code that follows the loop. (the 1811 // false branch). 1812 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1813 1814 // There can be no more statements in the condition block since we loop back 1815 // to this block. NULL out Block to force lazy creation of another block. 1816 Block = NULL; 1817 1818 // Return the condition block, which is the dominating block for the loop. 1819 Succ = EntryConditionBlock; 1820 return EntryConditionBlock; 1821} 1822 1823 1824CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1825 // FIXME: For now we pretend that @catch and the code it contains does not 1826 // exit. 1827 return Block; 1828} 1829 1830CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1831 // FIXME: This isn't complete. We basically treat @throw like a return 1832 // statement. 1833 1834 // If we were in the middle of a block we stop processing that block. 1835 if (badCFG) 1836 return 0; 1837 1838 // Create the new block. 1839 Block = createBlock(false); 1840 1841 // The Exit block is the only successor. 1842 AddSuccessor(Block, &cfg->getExit()); 1843 1844 // Add the statement to the block. This may create new blocks if S contains 1845 // control-flow (short-circuit operations). 1846 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1847} 1848 1849CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1850 // If we were in the middle of a block we stop processing that block. 1851 if (badCFG) 1852 return 0; 1853 1854 // Create the new block. 1855 Block = createBlock(false); 1856 1857 if (TryTerminatedBlock) 1858 // The current try statement is the only successor. 1859 AddSuccessor(Block, TryTerminatedBlock); 1860 else 1861 // otherwise the Exit block is the only successor. 1862 AddSuccessor(Block, &cfg->getExit()); 1863 1864 // Add the statement to the block. This may create new blocks if S contains 1865 // control-flow (short-circuit operations). 1866 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1867} 1868 1869CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1870 CFGBlock* LoopSuccessor = NULL; 1871 1872 // "do...while" is a control-flow statement. Thus we stop processing the 1873 // current block. 1874 if (Block) { 1875 if (badCFG) 1876 return 0; 1877 LoopSuccessor = Block; 1878 } else 1879 LoopSuccessor = Succ; 1880 1881 // Because of short-circuit evaluation, the condition of the loop can span 1882 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1883 // evaluate the condition. 1884 CFGBlock* ExitConditionBlock = createBlock(false); 1885 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1886 1887 // Set the terminator for the "exit" condition block. 1888 ExitConditionBlock->setTerminator(D); 1889 1890 // Now add the actual condition to the condition block. Because the condition 1891 // itself may contain control-flow, new blocks may be created. 1892 if (Stmt* C = D->getCond()) { 1893 Block = ExitConditionBlock; 1894 EntryConditionBlock = addStmt(C); 1895 if (Block) { 1896 if (badCFG) 1897 return 0; 1898 } 1899 } 1900 1901 // The condition block is the implicit successor for the loop body. 1902 Succ = EntryConditionBlock; 1903 1904 // See if this is a known constant. 1905 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1906 1907 // Process the loop body. 1908 CFGBlock* BodyBlock = NULL; 1909 { 1910 assert(D->getBody()); 1911 1912 // Save the current values for Block, Succ, and continue and break targets 1913 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1914 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1915 save_break(BreakJumpTarget); 1916 1917 // All continues within this loop should go to the condition block 1918 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1919 1920 // All breaks should go to the code following the loop. 1921 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1922 1923 // NULL out Block to force lazy instantiation of blocks for the body. 1924 Block = NULL; 1925 1926 // If body is not a compound statement create implicit scope 1927 // and add destructors. 1928 if (!isa<CompoundStmt>(D->getBody())) 1929 addLocalScopeAndDtors(D->getBody()); 1930 1931 // Create the body. The returned block is the entry to the loop body. 1932 BodyBlock = addStmt(D->getBody()); 1933 1934 if (!BodyBlock) 1935 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1936 else if (Block) { 1937 if (badCFG) 1938 return 0; 1939 } 1940 1941 if (!KnownVal.isFalse()) { 1942 // Add an intermediate block between the BodyBlock and the 1943 // ExitConditionBlock to represent the "loop back" transition. Create an 1944 // empty block to represent the transition block for looping back to the 1945 // head of the loop. 1946 // FIXME: Can we do this more efficiently without adding another block? 1947 Block = NULL; 1948 Succ = BodyBlock; 1949 CFGBlock *LoopBackBlock = createBlock(); 1950 LoopBackBlock->setLoopTarget(D); 1951 1952 // Add the loop body entry as a successor to the condition. 1953 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1954 } 1955 else 1956 AddSuccessor(ExitConditionBlock, NULL); 1957 } 1958 1959 // Link up the condition block with the code that follows the loop. 1960 // (the false branch). 1961 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1962 1963 // There can be no more statements in the body block(s) since we loop back to 1964 // the body. NULL out Block to force lazy creation of another block. 1965 Block = NULL; 1966 1967 // Return the loop body, which is the dominating block for the loop. 1968 Succ = BodyBlock; 1969 return BodyBlock; 1970} 1971 1972CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1973 // "continue" is a control-flow statement. Thus we stop processing the 1974 // current block. 1975 if (badCFG) 1976 return 0; 1977 1978 // Now create a new block that ends with the continue statement. 1979 Block = createBlock(false); 1980 Block->setTerminator(C); 1981 1982 // If there is no target for the continue, then we are looking at an 1983 // incomplete AST. This means the CFG cannot be constructed. 1984 if (ContinueJumpTarget.Block) { 1985 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1986 AddSuccessor(Block, ContinueJumpTarget.Block); 1987 } else 1988 badCFG = true; 1989 1990 return Block; 1991} 1992 1993CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1994 AddStmtChoice asc) { 1995 1996 if (asc.alwaysAdd()) { 1997 autoCreateBlock(); 1998 AppendStmt(Block, E); 1999 } 2000 2001 // VLA types have expressions that must be evaluated. 2002 if (E->isArgumentType()) { 2003 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 2004 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2005 addStmt(VA->getSizeExpr()); 2006 } 2007 2008 return Block; 2009} 2010 2011/// VisitStmtExpr - Utility method to handle (nested) statement 2012/// expressions (a GCC extension). 2013CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2014 if (asc.alwaysAdd()) { 2015 autoCreateBlock(); 2016 AppendStmt(Block, SE); 2017 } 2018 return VisitCompoundStmt(SE->getSubStmt()); 2019} 2020 2021CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2022 // "switch" is a control-flow statement. Thus we stop processing the current 2023 // block. 2024 CFGBlock* SwitchSuccessor = NULL; 2025 2026 // Save local scope position because in case of condition variable ScopePos 2027 // won't be restored when traversing AST. 2028 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2029 2030 // Create local scope for possible condition variable. 2031 // Store scope position. Add implicit destructor. 2032 if (VarDecl* VD = Terminator->getConditionVariable()) { 2033 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2034 addLocalScopeForVarDecl(VD); 2035 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2036 } 2037 2038 if (Block) { 2039 if (badCFG) 2040 return 0; 2041 SwitchSuccessor = Block; 2042 } else SwitchSuccessor = Succ; 2043 2044 // Save the current "switch" context. 2045 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2046 save_default(DefaultCaseBlock); 2047 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2048 2049 // Set the "default" case to be the block after the switch statement. If the 2050 // switch statement contains a "default:", this value will be overwritten with 2051 // the block for that code. 2052 DefaultCaseBlock = SwitchSuccessor; 2053 2054 // Create a new block that will contain the switch statement. 2055 SwitchTerminatedBlock = createBlock(false); 2056 2057 // Now process the switch body. The code after the switch is the implicit 2058 // successor. 2059 Succ = SwitchSuccessor; 2060 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2061 2062 // When visiting the body, the case statements should automatically get linked 2063 // up to the switch. We also don't keep a pointer to the body, since all 2064 // control-flow from the switch goes to case/default statements. 2065 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2066 Block = NULL; 2067 2068 // If body is not a compound statement create implicit scope 2069 // and add destructors. 2070 if (!isa<CompoundStmt>(Terminator->getBody())) 2071 addLocalScopeAndDtors(Terminator->getBody()); 2072 2073 addStmt(Terminator->getBody()); 2074 if (Block) { 2075 if (badCFG) 2076 return 0; 2077 } 2078 2079 // If we have no "default:" case, the default transition is to the code 2080 // following the switch body. 2081 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2082 2083 // Add the terminator and condition in the switch block. 2084 SwitchTerminatedBlock->setTerminator(Terminator); 2085 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2086 Block = SwitchTerminatedBlock; 2087 Block = addStmt(Terminator->getCond()); 2088 2089 // Finally, if the SwitchStmt contains a condition variable, add both the 2090 // SwitchStmt and the condition variable initialization to the CFG. 2091 if (VarDecl *VD = Terminator->getConditionVariable()) { 2092 if (Expr *Init = VD->getInit()) { 2093 autoCreateBlock(); 2094 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2095 addStmt(Init); 2096 } 2097 } 2098 2099 return Block; 2100} 2101 2102CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2103 // CaseStmts are essentially labels, so they are the first statement in a 2104 // block. 2105 CFGBlock *TopBlock = 0, *LastBlock = 0; 2106 2107 if (Stmt *Sub = CS->getSubStmt()) { 2108 // For deeply nested chains of CaseStmts, instead of doing a recursion 2109 // (which can blow out the stack), manually unroll and create blocks 2110 // along the way. 2111 while (isa<CaseStmt>(Sub)) { 2112 CFGBlock *CurrentBlock = createBlock(false); 2113 CurrentBlock->setLabel(CS); 2114 2115 if (TopBlock) 2116 AddSuccessor(LastBlock, CurrentBlock); 2117 else 2118 TopBlock = CurrentBlock; 2119 2120 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2121 LastBlock = CurrentBlock; 2122 2123 CS = cast<CaseStmt>(Sub); 2124 Sub = CS->getSubStmt(); 2125 } 2126 2127 addStmt(Sub); 2128 } 2129 2130 CFGBlock* CaseBlock = Block; 2131 if (!CaseBlock) 2132 CaseBlock = createBlock(); 2133 2134 // Cases statements partition blocks, so this is the top of the basic block we 2135 // were processing (the "case XXX:" is the label). 2136 CaseBlock->setLabel(CS); 2137 2138 if (badCFG) 2139 return 0; 2140 2141 // Add this block to the list of successors for the block with the switch 2142 // statement. 2143 assert(SwitchTerminatedBlock); 2144 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2145 2146 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2147 Block = NULL; 2148 2149 if (TopBlock) { 2150 AddSuccessor(LastBlock, CaseBlock); 2151 Succ = TopBlock; 2152 } 2153 else { 2154 // This block is now the implicit successor of other blocks. 2155 Succ = CaseBlock; 2156 } 2157 2158 return Succ; 2159} 2160 2161CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2162 if (Terminator->getSubStmt()) 2163 addStmt(Terminator->getSubStmt()); 2164 2165 DefaultCaseBlock = Block; 2166 2167 if (!DefaultCaseBlock) 2168 DefaultCaseBlock = createBlock(); 2169 2170 // Default statements partition blocks, so this is the top of the basic block 2171 // we were processing (the "default:" is the label). 2172 DefaultCaseBlock->setLabel(Terminator); 2173 2174 if (badCFG) 2175 return 0; 2176 2177 // Unlike case statements, we don't add the default block to the successors 2178 // for the switch statement immediately. This is done when we finish 2179 // processing the switch statement. This allows for the default case 2180 // (including a fall-through to the code after the switch statement) to always 2181 // be the last successor of a switch-terminated block. 2182 2183 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2184 Block = NULL; 2185 2186 // This block is now the implicit successor of other blocks. 2187 Succ = DefaultCaseBlock; 2188 2189 return DefaultCaseBlock; 2190} 2191 2192CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2193 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2194 // current block. 2195 CFGBlock* TrySuccessor = NULL; 2196 2197 if (Block) { 2198 if (badCFG) 2199 return 0; 2200 TrySuccessor = Block; 2201 } else TrySuccessor = Succ; 2202 2203 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2204 2205 // Create a new block that will contain the try statement. 2206 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2207 // Add the terminator in the try block. 2208 NewTryTerminatedBlock->setTerminator(Terminator); 2209 2210 bool HasCatchAll = false; 2211 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2212 // The code after the try is the implicit successor. 2213 Succ = TrySuccessor; 2214 CXXCatchStmt *CS = Terminator->getHandler(h); 2215 if (CS->getExceptionDecl() == 0) { 2216 HasCatchAll = true; 2217 } 2218 Block = NULL; 2219 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2220 if (CatchBlock == 0) 2221 return 0; 2222 // Add this block to the list of successors for the block with the try 2223 // statement. 2224 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2225 } 2226 if (!HasCatchAll) { 2227 if (PrevTryTerminatedBlock) 2228 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2229 else 2230 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2231 } 2232 2233 // The code after the try is the implicit successor. 2234 Succ = TrySuccessor; 2235 2236 // Save the current "try" context. 2237 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2238 TryTerminatedBlock = NewTryTerminatedBlock; 2239 2240 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2241 Block = NULL; 2242 Block = addStmt(Terminator->getTryBlock()); 2243 return Block; 2244} 2245 2246CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2247 // CXXCatchStmt are treated like labels, so they are the first statement in a 2248 // block. 2249 2250 // Save local scope position because in case of exception variable ScopePos 2251 // won't be restored when traversing AST. 2252 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2253 2254 // Create local scope for possible exception variable. 2255 // Store scope position. Add implicit destructor. 2256 if (VarDecl* VD = CS->getExceptionDecl()) { 2257 LocalScope::const_iterator BeginScopePos = ScopePos; 2258 addLocalScopeForVarDecl(VD); 2259 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2260 } 2261 2262 if (CS->getHandlerBlock()) 2263 addStmt(CS->getHandlerBlock()); 2264 2265 CFGBlock* CatchBlock = Block; 2266 if (!CatchBlock) 2267 CatchBlock = createBlock(); 2268 2269 CatchBlock->setLabel(CS); 2270 2271 if (badCFG) 2272 return 0; 2273 2274 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2275 Block = NULL; 2276 2277 return CatchBlock; 2278} 2279 2280CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2281 AddStmtChoice asc) { 2282 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2283 : AddStmtChoice::AlwaysAdd; 2284 autoCreateBlock(); 2285 AppendStmt(Block, C, AddStmtChoice(K)); 2286 return VisitChildren(C); 2287} 2288 2289CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2290 // Lazily create the indirect-goto dispatch block if there isn't one already. 2291 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2292 2293 if (!IBlock) { 2294 IBlock = createBlock(false); 2295 cfg->setIndirectGotoBlock(IBlock); 2296 } 2297 2298 // IndirectGoto is a control-flow statement. Thus we stop processing the 2299 // current block and create a new one. 2300 if (badCFG) 2301 return 0; 2302 2303 Block = createBlock(false); 2304 Block->setTerminator(I); 2305 AddSuccessor(Block, IBlock); 2306 return addStmt(I->getTarget()); 2307} 2308 2309} // end anonymous namespace 2310 2311/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2312/// no successors or predecessors. If this is the first block created in the 2313/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2314CFGBlock* CFG::createBlock() { 2315 bool first_block = begin() == end(); 2316 2317 // Create the block. 2318 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2319 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2320 Blocks.push_back(Mem, BlkBVC); 2321 2322 // If this is the first block, set it as the Entry and Exit. 2323 if (first_block) 2324 Entry = Exit = &back(); 2325 2326 // Return the block. 2327 return &back(); 2328} 2329 2330/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2331/// CFG is returned to the caller. 2332CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2333 BuildOptions BO) { 2334 CFGBuilder Builder; 2335 return Builder.buildCFG(D, Statement, C, BO); 2336} 2337 2338//===----------------------------------------------------------------------===// 2339// CFG: Queries for BlkExprs. 2340//===----------------------------------------------------------------------===// 2341 2342namespace { 2343 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2344} 2345 2346static void FindSubExprAssignments(Stmt *S, 2347 llvm::SmallPtrSet<Expr*,50>& Set) { 2348 if (!S) 2349 return; 2350 2351 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2352 Stmt *child = *I; 2353 if (!child) 2354 continue; 2355 2356 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2357 if (B->isAssignmentOp()) Set.insert(B); 2358 2359 FindSubExprAssignments(child, Set); 2360 } 2361} 2362 2363static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2364 BlkExprMapTy* M = new BlkExprMapTy(); 2365 2366 // Look for assignments that are used as subexpressions. These are the only 2367 // assignments that we want to *possibly* register as a block-level 2368 // expression. Basically, if an assignment occurs both in a subexpression and 2369 // at the block-level, it is a block-level expression. 2370 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2371 2372 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2373 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2374 if (CFGStmt S = BI->getAs<CFGStmt>()) 2375 FindSubExprAssignments(S, SubExprAssignments); 2376 2377 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2378 2379 // Iterate over the statements again on identify the Expr* and Stmt* at the 2380 // block-level that are block-level expressions. 2381 2382 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2383 CFGStmt CS = BI->getAs<CFGStmt>(); 2384 if (!CS.isValid()) 2385 continue; 2386 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2387 2388 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2389 // Assignment expressions that are not nested within another 2390 // expression are really "statements" whose value is never used by 2391 // another expression. 2392 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2393 continue; 2394 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2395 // Special handling for statement expressions. The last statement in 2396 // the statement expression is also a block-level expr. 2397 const CompoundStmt* C = Terminator->getSubStmt(); 2398 if (!C->body_empty()) { 2399 unsigned x = M->size(); 2400 (*M)[C->body_back()] = x; 2401 } 2402 } 2403 2404 unsigned x = M->size(); 2405 (*M)[Exp] = x; 2406 } 2407 } 2408 2409 // Look at terminators. The condition is a block-level expression. 2410 2411 Stmt* S = (*I)->getTerminatorCondition(); 2412 2413 if (S && M->find(S) == M->end()) { 2414 unsigned x = M->size(); 2415 (*M)[S] = x; 2416 } 2417 } 2418 2419 return M; 2420} 2421 2422CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2423 assert(S != NULL); 2424 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2425 2426 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2427 BlkExprMapTy::iterator I = M->find(S); 2428 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2429} 2430 2431unsigned CFG::getNumBlkExprs() { 2432 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2433 return M->size(); 2434 else { 2435 // We assume callers interested in the number of BlkExprs will want 2436 // the map constructed if it doesn't already exist. 2437 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2438 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2439 } 2440} 2441 2442//===----------------------------------------------------------------------===// 2443// Filtered walking of the CFG. 2444//===----------------------------------------------------------------------===// 2445 2446bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2447 const CFGBlock *From, const CFGBlock *To) { 2448 2449 if (F.IgnoreDefaultsWithCoveredEnums) { 2450 // If the 'To' has no label or is labeled but the label isn't a 2451 // CaseStmt then filter this edge. 2452 if (const SwitchStmt *S = 2453 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2454 if (S->isAllEnumCasesCovered()) { 2455 const Stmt *L = To->getLabel(); 2456 if (!L || !isa<CaseStmt>(L)) 2457 return true; 2458 } 2459 } 2460 } 2461 2462 return false; 2463} 2464 2465//===----------------------------------------------------------------------===// 2466// Cleanup: CFG dstor. 2467//===----------------------------------------------------------------------===// 2468 2469CFG::~CFG() { 2470 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2471} 2472 2473//===----------------------------------------------------------------------===// 2474// CFG pretty printing 2475//===----------------------------------------------------------------------===// 2476 2477namespace { 2478 2479class StmtPrinterHelper : public PrinterHelper { 2480 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2481 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2482 StmtMapTy StmtMap; 2483 DeclMapTy DeclMap; 2484 signed CurrentBlock; 2485 unsigned CurrentStmt; 2486 const LangOptions &LangOpts; 2487public: 2488 2489 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2490 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2491 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2492 unsigned j = 1; 2493 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2494 BI != BEnd; ++BI, ++j ) { 2495 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2496 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2497 StmtMap[SE] = P; 2498 2499 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2500 DeclMap[DS->getSingleDecl()] = P; 2501 2502 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2503 if (VarDecl* VD = IS->getConditionVariable()) 2504 DeclMap[VD] = P; 2505 2506 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2507 if (VarDecl* VD = FS->getConditionVariable()) 2508 DeclMap[VD] = P; 2509 2510 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2511 if (VarDecl* VD = WS->getConditionVariable()) 2512 DeclMap[VD] = P; 2513 2514 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2515 if (VarDecl* VD = SS->getConditionVariable()) 2516 DeclMap[VD] = P; 2517 2518 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2519 if (VarDecl* VD = CS->getExceptionDecl()) 2520 DeclMap[VD] = P; 2521 } 2522 } 2523 } 2524 } 2525 } 2526 2527 virtual ~StmtPrinterHelper() {} 2528 2529 const LangOptions &getLangOpts() const { return LangOpts; } 2530 void setBlockID(signed i) { CurrentBlock = i; } 2531 void setStmtID(unsigned i) { CurrentStmt = i; } 2532 2533 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2534 StmtMapTy::iterator I = StmtMap.find(S); 2535 2536 if (I == StmtMap.end()) 2537 return false; 2538 2539 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2540 && I->second.second == CurrentStmt) { 2541 return false; 2542 } 2543 2544 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2545 return true; 2546 } 2547 2548 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2549 DeclMapTy::iterator I = DeclMap.find(D); 2550 2551 if (I == DeclMap.end()) 2552 return false; 2553 2554 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2555 && I->second.second == CurrentStmt) { 2556 return false; 2557 } 2558 2559 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2560 return true; 2561 } 2562}; 2563} // end anonymous namespace 2564 2565 2566namespace { 2567class CFGBlockTerminatorPrint 2568 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2569 2570 llvm::raw_ostream& OS; 2571 StmtPrinterHelper* Helper; 2572 PrintingPolicy Policy; 2573public: 2574 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2575 const PrintingPolicy &Policy) 2576 : OS(os), Helper(helper), Policy(Policy) {} 2577 2578 void VisitIfStmt(IfStmt* I) { 2579 OS << "if "; 2580 I->getCond()->printPretty(OS,Helper,Policy); 2581 } 2582 2583 // Default case. 2584 void VisitStmt(Stmt* Terminator) { 2585 Terminator->printPretty(OS, Helper, Policy); 2586 } 2587 2588 void VisitForStmt(ForStmt* F) { 2589 OS << "for (" ; 2590 if (F->getInit()) 2591 OS << "..."; 2592 OS << "; "; 2593 if (Stmt* C = F->getCond()) 2594 C->printPretty(OS, Helper, Policy); 2595 OS << "; "; 2596 if (F->getInc()) 2597 OS << "..."; 2598 OS << ")"; 2599 } 2600 2601 void VisitWhileStmt(WhileStmt* W) { 2602 OS << "while " ; 2603 if (Stmt* C = W->getCond()) 2604 C->printPretty(OS, Helper, Policy); 2605 } 2606 2607 void VisitDoStmt(DoStmt* D) { 2608 OS << "do ... while "; 2609 if (Stmt* C = D->getCond()) 2610 C->printPretty(OS, Helper, Policy); 2611 } 2612 2613 void VisitSwitchStmt(SwitchStmt* Terminator) { 2614 OS << "switch "; 2615 Terminator->getCond()->printPretty(OS, Helper, Policy); 2616 } 2617 2618 void VisitCXXTryStmt(CXXTryStmt* CS) { 2619 OS << "try ..."; 2620 } 2621 2622 void VisitConditionalOperator(ConditionalOperator* C) { 2623 C->getCond()->printPretty(OS, Helper, Policy); 2624 OS << " ? ... : ..."; 2625 } 2626 2627 void VisitChooseExpr(ChooseExpr* C) { 2628 OS << "__builtin_choose_expr( "; 2629 C->getCond()->printPretty(OS, Helper, Policy); 2630 OS << " )"; 2631 } 2632 2633 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2634 OS << "goto *"; 2635 I->getTarget()->printPretty(OS, Helper, Policy); 2636 } 2637 2638 void VisitBinaryOperator(BinaryOperator* B) { 2639 if (!B->isLogicalOp()) { 2640 VisitExpr(B); 2641 return; 2642 } 2643 2644 B->getLHS()->printPretty(OS, Helper, Policy); 2645 2646 switch (B->getOpcode()) { 2647 case BO_LOr: 2648 OS << " || ..."; 2649 return; 2650 case BO_LAnd: 2651 OS << " && ..."; 2652 return; 2653 default: 2654 assert(false && "Invalid logical operator."); 2655 } 2656 } 2657 2658 void VisitExpr(Expr* E) { 2659 E->printPretty(OS, Helper, Policy); 2660 } 2661}; 2662} // end anonymous namespace 2663 2664static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2665 const CFGElement &E) { 2666 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2667 Stmt *S = CS; 2668 2669 if (Helper) { 2670 2671 // special printing for statement-expressions. 2672 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2673 CompoundStmt* Sub = SE->getSubStmt(); 2674 2675 if (Sub->child_begin() != Sub->child_end()) { 2676 OS << "({ ... ; "; 2677 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2678 OS << " })\n"; 2679 return; 2680 } 2681 } 2682 // special printing for comma expressions. 2683 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2684 if (B->getOpcode() == BO_Comma) { 2685 OS << "... , "; 2686 Helper->handledStmt(B->getRHS(),OS); 2687 OS << '\n'; 2688 return; 2689 } 2690 } 2691 } 2692 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2693 2694 if (isa<CXXOperatorCallExpr>(S)) { 2695 OS << " (OperatorCall)"; 2696 } 2697 else if (isa<CXXBindTemporaryExpr>(S)) { 2698 OS << " (BindTemporary)"; 2699 } 2700 2701 // Expressions need a newline. 2702 if (isa<Expr>(S)) 2703 OS << '\n'; 2704 2705 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2706 CXXBaseOrMemberInitializer* I = IE; 2707 if (I->isBaseInitializer()) 2708 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2709 else OS << I->getMember()->getName(); 2710 2711 OS << "("; 2712 if (Expr* IE = I->getInit()) 2713 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2714 OS << ")"; 2715 2716 if (I->isBaseInitializer()) 2717 OS << " (Base initializer)\n"; 2718 else OS << " (Member initializer)\n"; 2719 2720 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2721 VarDecl* VD = DE.getVarDecl(); 2722 Helper->handleDecl(VD, OS); 2723 2724 const Type* T = VD->getType().getTypePtr(); 2725 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2726 T = RT->getPointeeType().getTypePtr(); 2727 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 2728 T = ET; 2729 2730 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2731 OS << " (Implicit destructor)\n"; 2732 2733 } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { 2734 const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); 2735 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 2736 OS << " (Base object destructor)\n"; 2737 2738 } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { 2739 FieldDecl *FD = ME.getFieldDecl(); 2740 2741 const Type *T = FD->getType().getTypePtr(); 2742 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 2743 T = ET; 2744 2745 OS << "this->" << FD->getName(); 2746 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 2747 OS << " (Member object destructor)\n"; 2748 } 2749 } 2750 2751static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2752 const CFGBlock& B, 2753 StmtPrinterHelper* Helper, bool print_edges) { 2754 2755 if (Helper) Helper->setBlockID(B.getBlockID()); 2756 2757 // Print the header. 2758 OS << "\n [ B" << B.getBlockID(); 2759 2760 if (&B == &cfg->getEntry()) 2761 OS << " (ENTRY) ]\n"; 2762 else if (&B == &cfg->getExit()) 2763 OS << " (EXIT) ]\n"; 2764 else if (&B == cfg->getIndirectGotoBlock()) 2765 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2766 else 2767 OS << " ]\n"; 2768 2769 // Print the label of this block. 2770 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2771 2772 if (print_edges) 2773 OS << " "; 2774 2775 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2776 OS << L->getName(); 2777 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2778 OS << "case "; 2779 C->getLHS()->printPretty(OS, Helper, 2780 PrintingPolicy(Helper->getLangOpts())); 2781 if (C->getRHS()) { 2782 OS << " ... "; 2783 C->getRHS()->printPretty(OS, Helper, 2784 PrintingPolicy(Helper->getLangOpts())); 2785 } 2786 } else if (isa<DefaultStmt>(Label)) 2787 OS << "default"; 2788 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2789 OS << "catch ("; 2790 if (CS->getExceptionDecl()) 2791 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2792 0); 2793 else 2794 OS << "..."; 2795 OS << ")"; 2796 2797 } else 2798 assert(false && "Invalid label statement in CFGBlock."); 2799 2800 OS << ":\n"; 2801 } 2802 2803 // Iterate through the statements in the block and print them. 2804 unsigned j = 1; 2805 2806 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2807 I != E ; ++I, ++j ) { 2808 2809 // Print the statement # in the basic block and the statement itself. 2810 if (print_edges) 2811 OS << " "; 2812 2813 OS << llvm::format("%3d", j) << ": "; 2814 2815 if (Helper) 2816 Helper->setStmtID(j); 2817 2818 print_elem(OS,Helper,*I); 2819 } 2820 2821 // Print the terminator of this block. 2822 if (B.getTerminator()) { 2823 if (print_edges) 2824 OS << " "; 2825 2826 OS << " T: "; 2827 2828 if (Helper) Helper->setBlockID(-1); 2829 2830 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2831 PrintingPolicy(Helper->getLangOpts())); 2832 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2833 OS << '\n'; 2834 } 2835 2836 if (print_edges) { 2837 // Print the predecessors of this block. 2838 OS << " Predecessors (" << B.pred_size() << "):"; 2839 unsigned i = 0; 2840 2841 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2842 I != E; ++I, ++i) { 2843 2844 if (i == 8 || (i-8) == 0) 2845 OS << "\n "; 2846 2847 OS << " B" << (*I)->getBlockID(); 2848 } 2849 2850 OS << '\n'; 2851 2852 // Print the successors of this block. 2853 OS << " Successors (" << B.succ_size() << "):"; 2854 i = 0; 2855 2856 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2857 I != E; ++I, ++i) { 2858 2859 if (i == 8 || (i-8) % 10 == 0) 2860 OS << "\n "; 2861 2862 if (*I) 2863 OS << " B" << (*I)->getBlockID(); 2864 else 2865 OS << " NULL"; 2866 } 2867 2868 OS << '\n'; 2869 } 2870} 2871 2872 2873/// dump - A simple pretty printer of a CFG that outputs to stderr. 2874void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2875 2876/// print - A simple pretty printer of a CFG that outputs to an ostream. 2877void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2878 StmtPrinterHelper Helper(this, LO); 2879 2880 // Print the entry block. 2881 print_block(OS, this, getEntry(), &Helper, true); 2882 2883 // Iterate through the CFGBlocks and print them one by one. 2884 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2885 // Skip the entry block, because we already printed it. 2886 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2887 continue; 2888 2889 print_block(OS, this, **I, &Helper, true); 2890 } 2891 2892 // Print the exit block. 2893 print_block(OS, this, getExit(), &Helper, true); 2894 OS.flush(); 2895} 2896 2897/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2898void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2899 print(llvm::errs(), cfg, LO); 2900} 2901 2902/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2903/// Generally this will only be called from CFG::print. 2904void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2905 const LangOptions &LO) const { 2906 StmtPrinterHelper Helper(cfg, LO); 2907 print_block(OS, cfg, *this, &Helper, true); 2908} 2909 2910/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2911void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2912 const LangOptions &LO) const { 2913 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2914 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2915} 2916 2917Stmt* CFGBlock::getTerminatorCondition() { 2918 2919 if (!Terminator) 2920 return NULL; 2921 2922 Expr* E = NULL; 2923 2924 switch (Terminator->getStmtClass()) { 2925 default: 2926 break; 2927 2928 case Stmt::ForStmtClass: 2929 E = cast<ForStmt>(Terminator)->getCond(); 2930 break; 2931 2932 case Stmt::WhileStmtClass: 2933 E = cast<WhileStmt>(Terminator)->getCond(); 2934 break; 2935 2936 case Stmt::DoStmtClass: 2937 E = cast<DoStmt>(Terminator)->getCond(); 2938 break; 2939 2940 case Stmt::IfStmtClass: 2941 E = cast<IfStmt>(Terminator)->getCond(); 2942 break; 2943 2944 case Stmt::ChooseExprClass: 2945 E = cast<ChooseExpr>(Terminator)->getCond(); 2946 break; 2947 2948 case Stmt::IndirectGotoStmtClass: 2949 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2950 break; 2951 2952 case Stmt::SwitchStmtClass: 2953 E = cast<SwitchStmt>(Terminator)->getCond(); 2954 break; 2955 2956 case Stmt::ConditionalOperatorClass: 2957 E = cast<ConditionalOperator>(Terminator)->getCond(); 2958 break; 2959 2960 case Stmt::BinaryOperatorClass: // '&&' and '||' 2961 E = cast<BinaryOperator>(Terminator)->getLHS(); 2962 break; 2963 2964 case Stmt::ObjCForCollectionStmtClass: 2965 return Terminator; 2966 } 2967 2968 return E ? E->IgnoreParens() : NULL; 2969} 2970 2971bool CFGBlock::hasBinaryBranchTerminator() const { 2972 2973 if (!Terminator) 2974 return false; 2975 2976 Expr* E = NULL; 2977 2978 switch (Terminator->getStmtClass()) { 2979 default: 2980 return false; 2981 2982 case Stmt::ForStmtClass: 2983 case Stmt::WhileStmtClass: 2984 case Stmt::DoStmtClass: 2985 case Stmt::IfStmtClass: 2986 case Stmt::ChooseExprClass: 2987 case Stmt::ConditionalOperatorClass: 2988 case Stmt::BinaryOperatorClass: 2989 return true; 2990 } 2991 2992 return E ? E->IgnoreParens() : NULL; 2993} 2994 2995 2996//===----------------------------------------------------------------------===// 2997// CFG Graphviz Visualization 2998//===----------------------------------------------------------------------===// 2999 3000 3001#ifndef NDEBUG 3002static StmtPrinterHelper* GraphHelper; 3003#endif 3004 3005void CFG::viewCFG(const LangOptions &LO) const { 3006#ifndef NDEBUG 3007 StmtPrinterHelper H(this, LO); 3008 GraphHelper = &H; 3009 llvm::ViewGraph(this,"CFG"); 3010 GraphHelper = NULL; 3011#endif 3012} 3013 3014namespace llvm { 3015template<> 3016struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3017 3018 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3019 3020 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3021 3022#ifndef NDEBUG 3023 std::string OutSStr; 3024 llvm::raw_string_ostream Out(OutSStr); 3025 print_block(Out,Graph, *Node, GraphHelper, false); 3026 std::string& OutStr = Out.str(); 3027 3028 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3029 3030 // Process string output to make it nicer... 3031 for (unsigned i = 0; i != OutStr.length(); ++i) 3032 if (OutStr[i] == '\n') { // Left justify 3033 OutStr[i] = '\\'; 3034 OutStr.insert(OutStr.begin()+i+1, 'l'); 3035 } 3036 3037 return OutStr; 3038#else 3039 return ""; 3040#endif 3041 } 3042}; 3043} // end namespace llvm 3044