CFG.cpp revision 9106582d6afd4e33bd39f3e7173acdbb4e9b7849
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39class AddStmtChoice { 40public: 41 enum Kind { NotAlwaysAdd = 0, 42 AlwaysAdd = 1, 43 AsLValueNotAlwaysAdd = 2, 44 AlwaysAddAsLValue = 3 }; 45 46 AddStmtChoice(Kind kind) : k(kind) {} 47 48 bool alwaysAdd() const { return (unsigned)k & 0x1; } 49 bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } 50 51private: 52 Kind k; 53}; 54 55/// LocalScope - Node in tree of local scopes created for C++ implicit 56/// destructor calls generation. It contains list of automatic variables 57/// declared in the scope and link to position in previous scope this scope 58/// began in. 59/// 60/// The process of creating local scopes is as follows: 61/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 62/// - Before processing statements in scope (e.g. CompoundStmt) create 63/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 64/// and set CFGBuilder::ScopePos to the end of new scope, 65/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 66/// at this VarDecl, 67/// - For every normal (without jump) end of scope add to CFGBlock destructors 68/// for objects in the current scope, 69/// - For every jump add to CFGBlock destructors for objects 70/// between CFGBuilder::ScopePos and local scope position saved for jump 71/// target. Thanks to C++ restrictions on goto jumps we can be sure that 72/// jump target position will be on the path to root from CFGBuilder::ScopePos 73/// (adding any variable that doesn't need constructor to be called to 74/// LocalScope can break this assumption), 75/// 76class LocalScope { 77public: 78 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 79 80 /// const_iterator - Iterates local scope backwards and jumps to previous 81 /// scope on reaching the beginning of currently iterated scope. 82 class const_iterator { 83 const LocalScope* Scope; 84 85 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 86 /// Invalid iterator (with null Scope) has VarIter equal to 0. 87 unsigned VarIter; 88 89 public: 90 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 91 /// Incrementing invalid iterator is allowed and will result in invalid 92 /// iterator. 93 const_iterator() 94 : Scope(NULL), VarIter(0) {} 95 96 /// Create valid iterator. In case when S.Prev is an invalid iterator and 97 /// I is equal to 0, this will create invalid iterator. 98 const_iterator(const LocalScope& S, unsigned I) 99 : Scope(&S), VarIter(I) { 100 // Iterator to "end" of scope is not allowed. Handle it by going up 101 // in scopes tree possibly up to invalid iterator in the root. 102 if (VarIter == 0 && Scope) 103 *this = Scope->Prev; 104 } 105 106 VarDecl* const* operator->() const { 107 assert (Scope && "Dereferencing invalid iterator is not allowed"); 108 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 109 return &Scope->Vars[VarIter - 1]; 110 } 111 VarDecl* operator*() const { 112 return *this->operator->(); 113 } 114 115 const_iterator& operator++() { 116 if (!Scope) 117 return *this; 118 119 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 120 --VarIter; 121 if (VarIter == 0) 122 *this = Scope->Prev; 123 return *this; 124 } 125 const_iterator operator++(int) { 126 const_iterator P = *this; 127 ++*this; 128 return P; 129 } 130 131 bool operator==(const const_iterator& rhs) const { 132 return Scope == rhs.Scope && VarIter == rhs.VarIter; 133 } 134 bool operator!=(const const_iterator& rhs) const { 135 return !(*this == rhs); 136 } 137 138 operator bool() const { 139 return *this != const_iterator(); 140 } 141 142 int distance(const_iterator L); 143 }; 144 145 friend class const_iterator; 146 147private: 148 /// Automatic variables in order of declaration. 149 AutomaticVarsTy Vars; 150 /// Iterator to variable in previous scope that was declared just before 151 /// begin of this scope. 152 const_iterator Prev; 153 154public: 155 /// Constructs empty scope linked to previous scope in specified place. 156 LocalScope(const_iterator P) 157 : Vars() 158 , Prev(P) {} 159 160 /// Begin of scope in direction of CFG building (backwards). 161 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 162 163 void addVar(VarDecl* VD) { 164 Vars.push_back(VD); 165 } 166}; 167 168/// distance - Calculates distance from this to L. L must be reachable from this 169/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 170/// number of scopes between this and L. 171int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 172 int D = 0; 173 const_iterator F = *this; 174 while (F.Scope != L.Scope) { 175 assert (F != const_iterator() 176 && "L iterator is not reachable from F iterator."); 177 D += F.VarIter; 178 F = F.Scope->Prev; 179 } 180 D += F.VarIter - L.VarIter; 181 return D; 182} 183 184/// BlockScopePosPair - Structure for specifying position in CFG during its 185/// build process. It consists of CFGBlock that specifies position in CFG graph 186/// and LocalScope::const_iterator that specifies position in LocalScope graph. 187struct BlockScopePosPair { 188 BlockScopePosPair() {} 189 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 190 : Block(B), ScopePos(S) {} 191 192 CFGBlock* Block; 193 LocalScope::const_iterator ScopePos; 194}; 195 196/// CFGBuilder - This class implements CFG construction from an AST. 197/// The builder is stateful: an instance of the builder should be used to only 198/// construct a single CFG. 199/// 200/// Example usage: 201/// 202/// CFGBuilder builder; 203/// CFG* cfg = builder.BuildAST(stmt1); 204/// 205/// CFG construction is done via a recursive walk of an AST. We actually parse 206/// the AST in reverse order so that the successor of a basic block is 207/// constructed prior to its predecessor. This allows us to nicely capture 208/// implicit fall-throughs without extra basic blocks. 209/// 210class CFGBuilder { 211 typedef BlockScopePosPair JumpTarget; 212 typedef BlockScopePosPair JumpSource; 213 214 ASTContext *Context; 215 llvm::OwningPtr<CFG> cfg; 216 217 CFGBlock* Block; 218 CFGBlock* Succ; 219 JumpTarget ContinueJumpTarget; 220 JumpTarget BreakJumpTarget; 221 CFGBlock* SwitchTerminatedBlock; 222 CFGBlock* DefaultCaseBlock; 223 CFGBlock* TryTerminatedBlock; 224 225 // Current position in local scope. 226 LocalScope::const_iterator ScopePos; 227 228 // LabelMap records the mapping from Label expressions to their jump targets. 229 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 230 LabelMapTy LabelMap; 231 232 // A list of blocks that end with a "goto" that must be backpatched to their 233 // resolved targets upon completion of CFG construction. 234 typedef std::vector<JumpSource> BackpatchBlocksTy; 235 BackpatchBlocksTy BackpatchBlocks; 236 237 // A list of labels whose address has been taken (for indirect gotos). 238 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 239 LabelSetTy AddressTakenLabels; 240 241 bool badCFG; 242 CFG::BuildOptions BuildOpts; 243 244public: 245 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 246 Block(NULL), Succ(NULL), 247 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 248 TryTerminatedBlock(NULL), badCFG(false) {} 249 250 // buildCFG - Used by external clients to construct the CFG. 251 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 252 CFG::BuildOptions BO); 253 254private: 255 // Visitors to walk an AST and construct the CFG. 256 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 257 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 258 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 259 CFGBlock *VisitBreakStmt(BreakStmt *B); 260 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 261 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 262 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 263 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 264 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 265 CFGBlock *VisitCaseStmt(CaseStmt *C); 266 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 267 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 268 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 269 CFGBlock *VisitContinueStmt(ContinueStmt *C); 270 CFGBlock *VisitDeclStmt(DeclStmt *DS); 271 CFGBlock *VisitDeclSubExpr(Decl* D); 272 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 273 CFGBlock *VisitDoStmt(DoStmt *D); 274 CFGBlock *VisitForStmt(ForStmt *F); 275 CFGBlock *VisitGotoStmt(GotoStmt* G); 276 CFGBlock *VisitIfStmt(IfStmt *I); 277 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 278 CFGBlock *VisitLabelStmt(LabelStmt *L); 279 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 280 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 281 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 282 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 283 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 284 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 285 CFGBlock *VisitReturnStmt(ReturnStmt* R); 286 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 287 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 288 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 289 CFGBlock *VisitWhileStmt(WhileStmt *W); 290 291 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 292 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 293 CFGBlock *VisitChildren(Stmt* S); 294 295 // NYS == Not Yet Supported 296 CFGBlock* NYS() { 297 badCFG = true; 298 return Block; 299 } 300 301 void autoCreateBlock() { if (!Block) Block = createBlock(); } 302 CFGBlock *createBlock(bool add_successor = true); 303 304 CFGBlock *addStmt(Stmt *S) { 305 return Visit(S, AddStmtChoice::AlwaysAdd); 306 } 307 CFGBlock *addInitializer(CXXBaseOrMemberInitializer *I); 308 void addAutomaticObjDtors(LocalScope::const_iterator B, 309 LocalScope::const_iterator E, Stmt* S); 310 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 311 312 // Local scopes creation. 313 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 314 315 void addLocalScopeForStmt(Stmt* S); 316 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 317 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 318 319 void addLocalScopeAndDtors(Stmt* S); 320 321 // Interface to CFGBlock - adding CFGElements. 322 void AppendStmt(CFGBlock *B, Stmt *S, 323 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 324 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 325 } 326 void appendInitializer(CFGBlock *B, CXXBaseOrMemberInitializer *I) { 327 B->appendInitializer(I, cfg->getBumpVectorContext()); 328 } 329 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 330 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 331 } 332 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 333 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 334 } 335 336 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 337 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 338 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 339 LocalScope::const_iterator E, Stmt* S); 340 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 341 LocalScope::const_iterator B, LocalScope::const_iterator E); 342 343 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 344 B->addSuccessor(S, cfg->getBumpVectorContext()); 345 } 346 347 /// TryResult - a class representing a variant over the values 348 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 349 /// and is used by the CFGBuilder to decide if a branch condition 350 /// can be decided up front during CFG construction. 351 class TryResult { 352 int X; 353 public: 354 TryResult(bool b) : X(b ? 1 : 0) {} 355 TryResult() : X(-1) {} 356 357 bool isTrue() const { return X == 1; } 358 bool isFalse() const { return X == 0; } 359 bool isKnown() const { return X >= 0; } 360 void negate() { 361 assert(isKnown()); 362 X ^= 0x1; 363 } 364 }; 365 366 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 367 /// if we can evaluate to a known value, otherwise return -1. 368 TryResult TryEvaluateBool(Expr *S) { 369 if (!BuildOpts.PruneTriviallyFalseEdges) 370 return TryResult(); 371 372 Expr::EvalResult Result; 373 if (!S->isTypeDependent() && !S->isValueDependent() && 374 S->Evaluate(Result, *Context) && Result.Val.isInt()) 375 return Result.Val.getInt().getBoolValue(); 376 377 return TryResult(); 378 } 379}; 380 381// FIXME: Add support for dependent-sized array types in C++? 382// Does it even make sense to build a CFG for an uninstantiated template? 383static VariableArrayType* FindVA(Type* t) { 384 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 385 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 386 if (vat->getSizeExpr()) 387 return vat; 388 389 t = vt->getElementType().getTypePtr(); 390 } 391 392 return 0; 393} 394 395/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 396/// arbitrary statement. Examples include a single expression or a function 397/// body (compound statement). The ownership of the returned CFG is 398/// transferred to the caller. If CFG construction fails, this method returns 399/// NULL. 400CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 401 CFG::BuildOptions BO) { 402 403 Context = C; 404 assert(cfg.get()); 405 if (!Statement) 406 return NULL; 407 408 BuildOpts = BO; 409 410 // Create an empty block that will serve as the exit block for the CFG. Since 411 // this is the first block added to the CFG, it will be implicitly registered 412 // as the exit block. 413 Succ = createBlock(); 414 assert(Succ == &cfg->getExit()); 415 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 416 417 if (BuildOpts.AddImplicitDtors) 418 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 419 addImplicitDtorsForDestructor(DD); 420 421 // Visit the statements and create the CFG. 422 CFGBlock *B = addStmt(Statement); 423 424 if (badCFG) 425 return NULL; 426 427 // For C++ constructor add initializers to CFG. 428 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 429 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 430 E = CD->init_rend(); I != E; ++I) { 431 B = addInitializer(*I); 432 if (badCFG) 433 return NULL; 434 } 435 } 436 437 if (B) 438 Succ = B; 439 440 // Backpatch the gotos whose label -> block mappings we didn't know when we 441 // encountered them. 442 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 443 E = BackpatchBlocks.end(); I != E; ++I ) { 444 445 CFGBlock* B = I->Block; 446 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 447 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 448 449 // If there is no target for the goto, then we are looking at an 450 // incomplete AST. Handle this by not registering a successor. 451 if (LI == LabelMap.end()) continue; 452 453 JumpTarget JT = LI->second; 454 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 455 AddSuccessor(B, JT.Block); 456 } 457 458 // Add successors to the Indirect Goto Dispatch block (if we have one). 459 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 460 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 461 E = AddressTakenLabels.end(); I != E; ++I ) { 462 463 // Lookup the target block. 464 LabelMapTy::iterator LI = LabelMap.find(*I); 465 466 // If there is no target block that contains label, then we are looking 467 // at an incomplete AST. Handle this by not registering a successor. 468 if (LI == LabelMap.end()) continue; 469 470 AddSuccessor(B, LI->second.Block); 471 } 472 473 // Create an empty entry block that has no predecessors. 474 cfg->setEntry(createBlock()); 475 476 return cfg.take(); 477} 478 479/// createBlock - Used to lazily create blocks that are connected 480/// to the current (global) succcessor. 481CFGBlock* CFGBuilder::createBlock(bool add_successor) { 482 CFGBlock* B = cfg->createBlock(); 483 if (add_successor && Succ) 484 AddSuccessor(B, Succ); 485 return B; 486} 487 488/// addInitializer - Add C++ base or member initializer element to CFG. 489CFGBlock *CFGBuilder::addInitializer(CXXBaseOrMemberInitializer *I) { 490 if (!BuildOpts.AddInitializers) 491 return Block; 492 493 autoCreateBlock(); 494 appendInitializer(Block, I); 495 496 if (Expr *Init = I->getInit()) { 497 AddStmtChoice::Kind K = AddStmtChoice::NotAlwaysAdd; 498 if (FieldDecl *FD = I->getMember()) 499 if (FD->getType()->isReferenceType()) 500 K = AddStmtChoice::AsLValueNotAlwaysAdd; 501 502 return Visit(Init, AddStmtChoice(K)); 503 } 504 505 return Block; 506} 507 508/// addAutomaticObjDtors - Add to current block automatic objects destructors 509/// for objects in range of local scope positions. Use S as trigger statement 510/// for destructors. 511void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 512 LocalScope::const_iterator E, Stmt* S) { 513 if (!BuildOpts.AddImplicitDtors) 514 return; 515 516 if (B == E) 517 return; 518 519 autoCreateBlock(); 520 appendAutomaticObjDtors(Block, B, E, S); 521} 522 523/// addImplicitDtorsForDestructor - Add implicit destructors generated for 524/// base and member objects in destructor. 525void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 526 assert (BuildOpts.AddImplicitDtors 527 && "Can be called only when dtors should be added"); 528 const CXXRecordDecl *RD = DD->getParent(); 529 530 // At the end destroy virtual base objects. 531 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 532 VE = RD->vbases_end(); VI != VE; ++VI) { 533 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 534 if (!CD->hasTrivialDestructor()) { 535 autoCreateBlock(); 536 appendBaseDtor(Block, VI); 537 } 538 } 539 540 // Before virtual bases destroy direct base objects. 541 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 542 BE = RD->bases_end(); BI != BE; ++BI) { 543 if (!BI->isVirtual()) { 544 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 545 if (!CD->hasTrivialDestructor()) { 546 autoCreateBlock(); 547 appendBaseDtor(Block, BI); 548 } 549 } 550 } 551 552 // First destroy member objects. 553 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 554 FE = RD->field_end(); FI != FE; ++FI) { 555 if (const CXXRecordDecl *CD = FI->getType()->getAsCXXRecordDecl()) 556 if (!CD->hasTrivialDestructor()) { 557 autoCreateBlock(); 558 appendMemberDtor(Block, *FI); 559 } 560 } 561} 562 563/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 564/// way return valid LocalScope object. 565LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 566 if (!Scope) { 567 Scope = cfg->getAllocator().Allocate<LocalScope>(); 568 new (Scope) LocalScope(ScopePos); 569 } 570 return Scope; 571} 572 573/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 574/// that should create implicit scope (e.g. if/else substatements). 575void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 576 if (!BuildOpts.AddImplicitDtors) 577 return; 578 579 LocalScope *Scope = 0; 580 581 // For compound statement we will be creating explicit scope. 582 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 583 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 584 ; BI != BE; ++BI) { 585 Stmt* SI = *BI; 586 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 587 SI = LS->getSubStmt(); 588 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 589 Scope = addLocalScopeForDeclStmt(DS, Scope); 590 } 591 return; 592 } 593 594 // For any other statement scope will be implicit and as such will be 595 // interesting only for DeclStmt. 596 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 597 S = LS->getSubStmt(); 598 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 599 addLocalScopeForDeclStmt(DS); 600} 601 602/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 603/// reuse Scope if not NULL. 604LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 605 LocalScope* Scope) { 606 if (!BuildOpts.AddImplicitDtors) 607 return Scope; 608 609 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 610 ; DI != DE; ++DI) { 611 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 612 Scope = addLocalScopeForVarDecl(VD, Scope); 613 } 614 return Scope; 615} 616 617/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 618/// create add scope for automatic objects and temporary objects bound to 619/// const reference. Will reuse Scope if not NULL. 620LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 621 LocalScope* Scope) { 622 if (!BuildOpts.AddImplicitDtors) 623 return Scope; 624 625 // Check if variable is local. 626 switch (VD->getStorageClass()) { 627 case SC_None: 628 case SC_Auto: 629 case SC_Register: 630 break; 631 default: return Scope; 632 } 633 634 // Check for const references bound to temporary. Set type to pointee. 635 QualType QT = VD->getType(); 636 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 637 QT = RT->getPointeeType(); 638 if (!QT.isConstQualified()) 639 return Scope; 640 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 641 return Scope; 642 } 643 644 // Check if type is a C++ class with non-trivial destructor. 645 646 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 647 if (!CD->hasTrivialDestructor()) { 648 // Add the variable to scope 649 Scope = createOrReuseLocalScope(Scope); 650 Scope->addVar(VD); 651 ScopePos = Scope->begin(); 652 } 653 return Scope; 654} 655 656/// addLocalScopeAndDtors - For given statement add local scope for it and 657/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 658void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 659 if (!BuildOpts.AddImplicitDtors) 660 return; 661 662 LocalScope::const_iterator scopeBeginPos = ScopePos; 663 addLocalScopeForStmt(S); 664 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 665} 666 667/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 668/// automatic storage duration to CFGBlock's elements vector. Insertion will be 669/// performed in place specified with iterator. 670void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 671 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 672 BumpVectorContext& C = cfg->getBumpVectorContext(); 673 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 674 while (B != E) 675 I = Blk->insertAutomaticObjDtor(I, *B++, S); 676} 677 678/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 679/// automatic storage duration to CFGBlock's elements vector. Elements will be 680/// appended to physical end of the vector which happens to be logical 681/// beginning. 682void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 683 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 684 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 685} 686 687/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 688/// variables with automatic storage duration to CFGBlock's elements vector. 689/// Elements will be prepended to physical beginning of the vector which 690/// happens to be logical end. Use blocks terminator as statement that specifies 691/// destructors call site. 692void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 693 LocalScope::const_iterator B, LocalScope::const_iterator E) { 694 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 695} 696 697/// Visit - Walk the subtree of a statement and add extra 698/// blocks for ternary operators, &&, and ||. We also process "," and 699/// DeclStmts (which may contain nested control-flow). 700CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 701tryAgain: 702 if (!S) { 703 badCFG = true; 704 return 0; 705 } 706 switch (S->getStmtClass()) { 707 default: 708 return VisitStmt(S, asc); 709 710 case Stmt::AddrLabelExprClass: 711 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 712 713 case Stmt::BinaryOperatorClass: 714 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 715 716 case Stmt::BlockExprClass: 717 return VisitBlockExpr(cast<BlockExpr>(S), asc); 718 719 case Stmt::BreakStmtClass: 720 return VisitBreakStmt(cast<BreakStmt>(S)); 721 722 case Stmt::CallExprClass: 723 case Stmt::CXXOperatorCallExprClass: 724 return VisitCallExpr(cast<CallExpr>(S), asc); 725 726 case Stmt::CaseStmtClass: 727 return VisitCaseStmt(cast<CaseStmt>(S)); 728 729 case Stmt::ChooseExprClass: 730 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 731 732 case Stmt::CompoundStmtClass: 733 return VisitCompoundStmt(cast<CompoundStmt>(S)); 734 735 case Stmt::ConditionalOperatorClass: 736 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 737 738 case Stmt::ContinueStmtClass: 739 return VisitContinueStmt(cast<ContinueStmt>(S)); 740 741 case Stmt::CXXCatchStmtClass: 742 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 743 744 case Stmt::CXXExprWithTemporariesClass: { 745 // FIXME: Handle temporaries. For now, just visit the subexpression 746 // so we don't artificially create extra blocks. 747 return Visit(cast<CXXExprWithTemporaries>(S)->getSubExpr(), asc); 748 } 749 750 case Stmt::CXXMemberCallExprClass: 751 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 752 753 case Stmt::CXXThrowExprClass: 754 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 755 756 case Stmt::CXXTryStmtClass: 757 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 758 759 case Stmt::DeclStmtClass: 760 return VisitDeclStmt(cast<DeclStmt>(S)); 761 762 case Stmt::DefaultStmtClass: 763 return VisitDefaultStmt(cast<DefaultStmt>(S)); 764 765 case Stmt::DoStmtClass: 766 return VisitDoStmt(cast<DoStmt>(S)); 767 768 case Stmt::ForStmtClass: 769 return VisitForStmt(cast<ForStmt>(S)); 770 771 case Stmt::GotoStmtClass: 772 return VisitGotoStmt(cast<GotoStmt>(S)); 773 774 case Stmt::IfStmtClass: 775 return VisitIfStmt(cast<IfStmt>(S)); 776 777 case Stmt::IndirectGotoStmtClass: 778 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 779 780 case Stmt::LabelStmtClass: 781 return VisitLabelStmt(cast<LabelStmt>(S)); 782 783 case Stmt::MemberExprClass: 784 return VisitMemberExpr(cast<MemberExpr>(S), asc); 785 786 case Stmt::ObjCAtCatchStmtClass: 787 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 788 789 case Stmt::ObjCAtSynchronizedStmtClass: 790 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 791 792 case Stmt::ObjCAtThrowStmtClass: 793 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 794 795 case Stmt::ObjCAtTryStmtClass: 796 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 797 798 case Stmt::ObjCForCollectionStmtClass: 799 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 800 801 case Stmt::ParenExprClass: 802 S = cast<ParenExpr>(S)->getSubExpr(); 803 goto tryAgain; 804 805 case Stmt::NullStmtClass: 806 return Block; 807 808 case Stmt::ReturnStmtClass: 809 return VisitReturnStmt(cast<ReturnStmt>(S)); 810 811 case Stmt::SizeOfAlignOfExprClass: 812 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 813 814 case Stmt::StmtExprClass: 815 return VisitStmtExpr(cast<StmtExpr>(S), asc); 816 817 case Stmt::SwitchStmtClass: 818 return VisitSwitchStmt(cast<SwitchStmt>(S)); 819 820 case Stmt::WhileStmtClass: 821 return VisitWhileStmt(cast<WhileStmt>(S)); 822 } 823} 824 825CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 826 if (asc.alwaysAdd()) { 827 autoCreateBlock(); 828 AppendStmt(Block, S, asc); 829 } 830 831 return VisitChildren(S); 832} 833 834/// VisitChildren - Visit the children of a Stmt. 835CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 836 CFGBlock *B = Block; 837 for (Stmt::child_iterator I = Terminator->child_begin(), 838 E = Terminator->child_end(); I != E; ++I) { 839 if (*I) B = Visit(*I); 840 } 841 return B; 842} 843 844CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 845 AddStmtChoice asc) { 846 AddressTakenLabels.insert(A->getLabel()); 847 848 if (asc.alwaysAdd()) { 849 autoCreateBlock(); 850 AppendStmt(Block, A, asc); 851 } 852 853 return Block; 854} 855 856CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 857 AddStmtChoice asc) { 858 if (B->isLogicalOp()) { // && or || 859 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 860 AppendStmt(ConfluenceBlock, B, asc); 861 862 if (badCFG) 863 return 0; 864 865 // create the block evaluating the LHS 866 CFGBlock* LHSBlock = createBlock(false); 867 LHSBlock->setTerminator(B); 868 869 // create the block evaluating the RHS 870 Succ = ConfluenceBlock; 871 Block = NULL; 872 CFGBlock* RHSBlock = addStmt(B->getRHS()); 873 874 if (RHSBlock) { 875 if (badCFG) 876 return 0; 877 } 878 else { 879 // Create an empty block for cases where the RHS doesn't require 880 // any explicit statements in the CFG. 881 RHSBlock = createBlock(); 882 } 883 884 // See if this is a known constant. 885 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 886 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 887 KnownVal.negate(); 888 889 // Now link the LHSBlock with RHSBlock. 890 if (B->getOpcode() == BO_LOr) { 891 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 892 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 893 } else { 894 assert(B->getOpcode() == BO_LAnd); 895 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 896 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 897 } 898 899 // Generate the blocks for evaluating the LHS. 900 Block = LHSBlock; 901 return addStmt(B->getLHS()); 902 } 903 else if (B->getOpcode() == BO_Comma) { // , 904 autoCreateBlock(); 905 AppendStmt(Block, B, asc); 906 addStmt(B->getRHS()); 907 return addStmt(B->getLHS()); 908 } 909 else if (B->isAssignmentOp()) { 910 if (asc.alwaysAdd()) { 911 autoCreateBlock(); 912 AppendStmt(Block, B, asc); 913 } 914 915 Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 916 return Visit(B->getRHS()); 917 } 918 919 if (asc.alwaysAdd()) { 920 autoCreateBlock(); 921 AppendStmt(Block, B, asc); 922 } 923 924 Visit(B->getRHS()); 925 return Visit(B->getLHS()); 926} 927 928CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 929 if (asc.alwaysAdd()) { 930 autoCreateBlock(); 931 AppendStmt(Block, E, asc); 932 } 933 return Block; 934} 935 936CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 937 // "break" is a control-flow statement. Thus we stop processing the current 938 // block. 939 if (badCFG) 940 return 0; 941 942 // Now create a new block that ends with the break statement. 943 Block = createBlock(false); 944 Block->setTerminator(B); 945 946 // If there is no target for the break, then we are looking at an incomplete 947 // AST. This means that the CFG cannot be constructed. 948 if (BreakJumpTarget.Block) { 949 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 950 AddSuccessor(Block, BreakJumpTarget.Block); 951 } else 952 badCFG = true; 953 954 955 return Block; 956} 957 958static bool CanThrow(Expr *E) { 959 QualType Ty = E->getType(); 960 if (Ty->isFunctionPointerType()) 961 Ty = Ty->getAs<PointerType>()->getPointeeType(); 962 else if (Ty->isBlockPointerType()) 963 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 964 965 const FunctionType *FT = Ty->getAs<FunctionType>(); 966 if (FT) { 967 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 968 if (Proto->hasEmptyExceptionSpec()) 969 return false; 970 } 971 return true; 972} 973 974CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 975 // If this is a call to a no-return function, this stops the block here. 976 bool NoReturn = false; 977 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 978 NoReturn = true; 979 } 980 981 bool AddEHEdge = false; 982 983 // Languages without exceptions are assumed to not throw. 984 if (Context->getLangOptions().Exceptions) { 985 if (BuildOpts.AddEHEdges) 986 AddEHEdge = true; 987 } 988 989 if (FunctionDecl *FD = C->getDirectCallee()) { 990 if (FD->hasAttr<NoReturnAttr>()) 991 NoReturn = true; 992 if (FD->hasAttr<NoThrowAttr>()) 993 AddEHEdge = false; 994 } 995 996 if (!CanThrow(C->getCallee())) 997 AddEHEdge = false; 998 999 if (!NoReturn && !AddEHEdge) { 1000 if (asc.asLValue()) 1001 return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue); 1002 else 1003 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 1004 } 1005 1006 if (Block) { 1007 Succ = Block; 1008 if (badCFG) 1009 return 0; 1010 } 1011 1012 Block = createBlock(!NoReturn); 1013 AppendStmt(Block, C, asc); 1014 1015 if (NoReturn) { 1016 // Wire this to the exit block directly. 1017 AddSuccessor(Block, &cfg->getExit()); 1018 } 1019 if (AddEHEdge) { 1020 // Add exceptional edges. 1021 if (TryTerminatedBlock) 1022 AddSuccessor(Block, TryTerminatedBlock); 1023 else 1024 AddSuccessor(Block, &cfg->getExit()); 1025 } 1026 1027 return VisitChildren(C); 1028} 1029 1030CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1031 AddStmtChoice asc) { 1032 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1033 AppendStmt(ConfluenceBlock, C, asc); 1034 if (badCFG) 1035 return 0; 1036 1037 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1038 : AddStmtChoice::AlwaysAdd; 1039 1040 Succ = ConfluenceBlock; 1041 Block = NULL; 1042 CFGBlock* LHSBlock = Visit(C->getLHS(), asc); 1043 if (badCFG) 1044 return 0; 1045 1046 Succ = ConfluenceBlock; 1047 Block = NULL; 1048 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1049 if (badCFG) 1050 return 0; 1051 1052 Block = createBlock(false); 1053 // See if this is a known constant. 1054 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1055 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1056 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1057 Block->setTerminator(C); 1058 return addStmt(C->getCond()); 1059} 1060 1061 1062CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1063 addLocalScopeAndDtors(C); 1064 CFGBlock* LastBlock = Block; 1065 1066 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1067 I != E; ++I ) { 1068 // If we hit a segment of code just containing ';' (NullStmts), we can 1069 // get a null block back. In such cases, just use the LastBlock 1070 if (CFGBlock *newBlock = addStmt(*I)) 1071 LastBlock = newBlock; 1072 1073 if (badCFG) 1074 return NULL; 1075 } 1076 1077 return LastBlock; 1078} 1079 1080CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1081 AddStmtChoice asc) { 1082 // Create the confluence block that will "merge" the results of the ternary 1083 // expression. 1084 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1085 AppendStmt(ConfluenceBlock, C, asc); 1086 if (badCFG) 1087 return 0; 1088 1089 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1090 : AddStmtChoice::AlwaysAdd; 1091 1092 // Create a block for the LHS expression if there is an LHS expression. A 1093 // GCC extension allows LHS to be NULL, causing the condition to be the 1094 // value that is returned instead. 1095 // e.g: x ?: y is shorthand for: x ? x : y; 1096 Succ = ConfluenceBlock; 1097 Block = NULL; 1098 CFGBlock* LHSBlock = NULL; 1099 if (C->getLHS()) { 1100 LHSBlock = Visit(C->getLHS(), asc); 1101 if (badCFG) 1102 return 0; 1103 Block = NULL; 1104 } 1105 1106 // Create the block for the RHS expression. 1107 Succ = ConfluenceBlock; 1108 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1109 if (badCFG) 1110 return 0; 1111 1112 // Create the block that will contain the condition. 1113 Block = createBlock(false); 1114 1115 // See if this is a known constant. 1116 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1117 if (LHSBlock) { 1118 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1119 } else { 1120 if (KnownVal.isFalse()) { 1121 // If we know the condition is false, add NULL as the successor for 1122 // the block containing the condition. In this case, the confluence 1123 // block will have just one predecessor. 1124 AddSuccessor(Block, 0); 1125 assert(ConfluenceBlock->pred_size() == 1); 1126 } else { 1127 // If we have no LHS expression, add the ConfluenceBlock as a direct 1128 // successor for the block containing the condition. Moreover, we need to 1129 // reverse the order of the predecessors in the ConfluenceBlock because 1130 // the RHSBlock will have been added to the succcessors already, and we 1131 // want the first predecessor to the the block containing the expression 1132 // for the case when the ternary expression evaluates to true. 1133 AddSuccessor(Block, ConfluenceBlock); 1134 assert(ConfluenceBlock->pred_size() == 2); 1135 std::reverse(ConfluenceBlock->pred_begin(), 1136 ConfluenceBlock->pred_end()); 1137 } 1138 } 1139 1140 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1141 Block->setTerminator(C); 1142 return addStmt(C->getCond()); 1143} 1144 1145CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1146 autoCreateBlock(); 1147 1148 if (DS->isSingleDecl()) { 1149 AppendStmt(Block, DS); 1150 return VisitDeclSubExpr(DS->getSingleDecl()); 1151 } 1152 1153 CFGBlock *B = 0; 1154 1155 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1156 typedef llvm::SmallVector<Decl*,10> BufTy; 1157 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1158 1159 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1160 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1161 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1162 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1163 1164 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1165 // automatically freed with the CFG. 1166 DeclGroupRef DG(*I); 1167 Decl *D = *I; 1168 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1169 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1170 1171 // Append the fake DeclStmt to block. 1172 AppendStmt(Block, DSNew); 1173 B = VisitDeclSubExpr(D); 1174 } 1175 1176 return B; 1177} 1178 1179/// VisitDeclSubExpr - Utility method to add block-level expressions for 1180/// initializers in Decls. 1181CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 1182 assert(Block); 1183 1184 VarDecl *VD = dyn_cast<VarDecl>(D); 1185 1186 if (!VD) 1187 return Block; 1188 1189 Expr *Init = VD->getInit(); 1190 1191 if (Init) { 1192 AddStmtChoice::Kind k = 1193 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 1194 : AddStmtChoice::NotAlwaysAdd; 1195 Visit(Init, AddStmtChoice(k)); 1196 } 1197 1198 // If the type of VD is a VLA, then we must process its size expressions. 1199 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1200 VA = FindVA(VA->getElementType().getTypePtr())) 1201 Block = addStmt(VA->getSizeExpr()); 1202 1203 // Remove variable from local scope. 1204 if (ScopePos && VD == *ScopePos) 1205 ++ScopePos; 1206 1207 return Block; 1208} 1209 1210CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1211 // We may see an if statement in the middle of a basic block, or it may be the 1212 // first statement we are processing. In either case, we create a new basic 1213 // block. First, we create the blocks for the then...else statements, and 1214 // then we create the block containing the if statement. If we were in the 1215 // middle of a block, we stop processing that block. That block is then the 1216 // implicit successor for the "then" and "else" clauses. 1217 1218 // Save local scope position because in case of condition variable ScopePos 1219 // won't be restored when traversing AST. 1220 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1221 1222 // Create local scope for possible condition variable. 1223 // Store scope position. Add implicit destructor. 1224 if (VarDecl* VD = I->getConditionVariable()) { 1225 LocalScope::const_iterator BeginScopePos = ScopePos; 1226 addLocalScopeForVarDecl(VD); 1227 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1228 } 1229 1230 // The block we were proccessing is now finished. Make it the successor 1231 // block. 1232 if (Block) { 1233 Succ = Block; 1234 if (badCFG) 1235 return 0; 1236 } 1237 1238 // Process the false branch. 1239 CFGBlock* ElseBlock = Succ; 1240 1241 if (Stmt* Else = I->getElse()) { 1242 SaveAndRestore<CFGBlock*> sv(Succ); 1243 1244 // NULL out Block so that the recursive call to Visit will 1245 // create a new basic block. 1246 Block = NULL; 1247 1248 // If branch is not a compound statement create implicit scope 1249 // and add destructors. 1250 if (!isa<CompoundStmt>(Else)) 1251 addLocalScopeAndDtors(Else); 1252 1253 ElseBlock = addStmt(Else); 1254 1255 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1256 ElseBlock = sv.get(); 1257 else if (Block) { 1258 if (badCFG) 1259 return 0; 1260 } 1261 } 1262 1263 // Process the true branch. 1264 CFGBlock* ThenBlock; 1265 { 1266 Stmt* Then = I->getThen(); 1267 assert(Then); 1268 SaveAndRestore<CFGBlock*> sv(Succ); 1269 Block = NULL; 1270 1271 // If branch is not a compound statement create implicit scope 1272 // and add destructors. 1273 if (!isa<CompoundStmt>(Then)) 1274 addLocalScopeAndDtors(Then); 1275 1276 ThenBlock = addStmt(Then); 1277 1278 if (!ThenBlock) { 1279 // We can reach here if the "then" body has all NullStmts. 1280 // Create an empty block so we can distinguish between true and false 1281 // branches in path-sensitive analyses. 1282 ThenBlock = createBlock(false); 1283 AddSuccessor(ThenBlock, sv.get()); 1284 } else if (Block) { 1285 if (badCFG) 1286 return 0; 1287 } 1288 } 1289 1290 // Now create a new block containing the if statement. 1291 Block = createBlock(false); 1292 1293 // Set the terminator of the new block to the If statement. 1294 Block->setTerminator(I); 1295 1296 // See if this is a known constant. 1297 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1298 1299 // Now add the successors. 1300 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1301 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1302 1303 // Add the condition as the last statement in the new block. This may create 1304 // new blocks as the condition may contain control-flow. Any newly created 1305 // blocks will be pointed to be "Block". 1306 Block = addStmt(I->getCond()); 1307 1308 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1309 // and the condition variable initialization to the CFG. 1310 if (VarDecl *VD = I->getConditionVariable()) { 1311 if (Expr *Init = VD->getInit()) { 1312 autoCreateBlock(); 1313 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1314 addStmt(Init); 1315 } 1316 } 1317 1318 return Block; 1319} 1320 1321 1322CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1323 // If we were in the middle of a block we stop processing that block. 1324 // 1325 // NOTE: If a "return" appears in the middle of a block, this means that the 1326 // code afterwards is DEAD (unreachable). We still keep a basic block 1327 // for that code; a simple "mark-and-sweep" from the entry block will be 1328 // able to report such dead blocks. 1329 1330 // Create the new block. 1331 Block = createBlock(false); 1332 1333 // The Exit block is the only successor. 1334 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1335 AddSuccessor(Block, &cfg->getExit()); 1336 1337 // Add the return statement to the block. This may create new blocks if R 1338 // contains control-flow (short-circuit operations). 1339 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1340} 1341 1342CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1343 // Get the block of the labeled statement. Add it to our map. 1344 addStmt(L->getSubStmt()); 1345 CFGBlock* LabelBlock = Block; 1346 1347 if (!LabelBlock) // This can happen when the body is empty, i.e. 1348 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1349 1350 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1351 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1352 1353 // Labels partition blocks, so this is the end of the basic block we were 1354 // processing (L is the block's label). Because this is label (and we have 1355 // already processed the substatement) there is no extra control-flow to worry 1356 // about. 1357 LabelBlock->setLabel(L); 1358 if (badCFG) 1359 return 0; 1360 1361 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1362 Block = NULL; 1363 1364 // This block is now the implicit successor of other blocks. 1365 Succ = LabelBlock; 1366 1367 return LabelBlock; 1368} 1369 1370CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1371 // Goto is a control-flow statement. Thus we stop processing the current 1372 // block and create a new one. 1373 1374 Block = createBlock(false); 1375 Block->setTerminator(G); 1376 1377 // If we already know the mapping to the label block add the successor now. 1378 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1379 1380 if (I == LabelMap.end()) 1381 // We will need to backpatch this block later. 1382 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1383 else { 1384 JumpTarget JT = I->second; 1385 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1386 AddSuccessor(Block, JT.Block); 1387 } 1388 1389 return Block; 1390} 1391 1392CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1393 CFGBlock* LoopSuccessor = NULL; 1394 1395 // Save local scope position because in case of condition variable ScopePos 1396 // won't be restored when traversing AST. 1397 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1398 1399 // Create local scope for init statement and possible condition variable. 1400 // Add destructor for init statement and condition variable. 1401 // Store scope position for continue statement. 1402 if (Stmt* Init = F->getInit()) 1403 addLocalScopeForStmt(Init); 1404 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1405 1406 if (VarDecl* VD = F->getConditionVariable()) 1407 addLocalScopeForVarDecl(VD); 1408 LocalScope::const_iterator ContinueScopePos = ScopePos; 1409 1410 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1411 1412 // "for" is a control-flow statement. Thus we stop processing the current 1413 // block. 1414 if (Block) { 1415 if (badCFG) 1416 return 0; 1417 LoopSuccessor = Block; 1418 } else 1419 LoopSuccessor = Succ; 1420 1421 // Save the current value for the break targets. 1422 // All breaks should go to the code following the loop. 1423 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1424 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1425 1426 // Because of short-circuit evaluation, the condition of the loop can span 1427 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1428 // evaluate the condition. 1429 CFGBlock* ExitConditionBlock = createBlock(false); 1430 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1431 1432 // Set the terminator for the "exit" condition block. 1433 ExitConditionBlock->setTerminator(F); 1434 1435 // Now add the actual condition to the condition block. Because the condition 1436 // itself may contain control-flow, new blocks may be created. 1437 if (Stmt* C = F->getCond()) { 1438 Block = ExitConditionBlock; 1439 EntryConditionBlock = addStmt(C); 1440 assert(Block == EntryConditionBlock || 1441 (Block == 0 && EntryConditionBlock == Succ)); 1442 1443 // If this block contains a condition variable, add both the condition 1444 // variable and initializer to the CFG. 1445 if (VarDecl *VD = F->getConditionVariable()) { 1446 if (Expr *Init = VD->getInit()) { 1447 autoCreateBlock(); 1448 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1449 EntryConditionBlock = addStmt(Init); 1450 assert(Block == EntryConditionBlock); 1451 } 1452 } 1453 1454 if (Block) { 1455 if (badCFG) 1456 return 0; 1457 } 1458 } 1459 1460 // The condition block is the implicit successor for the loop body as well as 1461 // any code above the loop. 1462 Succ = EntryConditionBlock; 1463 1464 // See if this is a known constant. 1465 TryResult KnownVal(true); 1466 1467 if (F->getCond()) 1468 KnownVal = TryEvaluateBool(F->getCond()); 1469 1470 // Now create the loop body. 1471 { 1472 assert(F->getBody()); 1473 1474 // Save the current values for Block, Succ, and continue targets. 1475 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1476 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1477 1478 // Create a new block to contain the (bottom) of the loop body. 1479 Block = NULL; 1480 1481 // Loop body should end with destructor of Condition variable (if any). 1482 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1483 1484 if (Stmt* I = F->getInc()) { 1485 // Generate increment code in its own basic block. This is the target of 1486 // continue statements. 1487 Succ = addStmt(I); 1488 } else { 1489 // No increment code. Create a special, empty, block that is used as the 1490 // target block for "looping back" to the start of the loop. 1491 assert(Succ == EntryConditionBlock); 1492 Succ = Block ? Block : createBlock(); 1493 } 1494 1495 // Finish up the increment (or empty) block if it hasn't been already. 1496 if (Block) { 1497 assert(Block == Succ); 1498 if (badCFG) 1499 return 0; 1500 Block = 0; 1501 } 1502 1503 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1504 1505 // The starting block for the loop increment is the block that should 1506 // represent the 'loop target' for looping back to the start of the loop. 1507 ContinueJumpTarget.Block->setLoopTarget(F); 1508 1509 // If body is not a compound statement create implicit scope 1510 // and add destructors. 1511 if (!isa<CompoundStmt>(F->getBody())) 1512 addLocalScopeAndDtors(F->getBody()); 1513 1514 // Now populate the body block, and in the process create new blocks as we 1515 // walk the body of the loop. 1516 CFGBlock* BodyBlock = addStmt(F->getBody()); 1517 1518 if (!BodyBlock) 1519 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1520 else if (badCFG) 1521 return 0; 1522 1523 // This new body block is a successor to our "exit" condition block. 1524 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1525 } 1526 1527 // Link up the condition block with the code that follows the loop. (the 1528 // false branch). 1529 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1530 1531 // If the loop contains initialization, create a new block for those 1532 // statements. This block can also contain statements that precede the loop. 1533 if (Stmt* I = F->getInit()) { 1534 Block = createBlock(); 1535 return addStmt(I); 1536 } else { 1537 // There is no loop initialization. We are thus basically a while loop. 1538 // NULL out Block to force lazy block construction. 1539 Block = NULL; 1540 Succ = EntryConditionBlock; 1541 return EntryConditionBlock; 1542 } 1543} 1544 1545CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1546 if (asc.alwaysAdd()) { 1547 autoCreateBlock(); 1548 AppendStmt(Block, M, asc); 1549 } 1550 return Visit(M->getBase(), 1551 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1552 : AddStmtChoice::AsLValueNotAlwaysAdd); 1553} 1554 1555CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1556 // Objective-C fast enumeration 'for' statements: 1557 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1558 // 1559 // for ( Type newVariable in collection_expression ) { statements } 1560 // 1561 // becomes: 1562 // 1563 // prologue: 1564 // 1. collection_expression 1565 // T. jump to loop_entry 1566 // loop_entry: 1567 // 1. side-effects of element expression 1568 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1569 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1570 // TB: 1571 // statements 1572 // T. jump to loop_entry 1573 // FB: 1574 // what comes after 1575 // 1576 // and 1577 // 1578 // Type existingItem; 1579 // for ( existingItem in expression ) { statements } 1580 // 1581 // becomes: 1582 // 1583 // the same with newVariable replaced with existingItem; the binding works 1584 // the same except that for one ObjCForCollectionStmt::getElement() returns 1585 // a DeclStmt and the other returns a DeclRefExpr. 1586 // 1587 1588 CFGBlock* LoopSuccessor = 0; 1589 1590 if (Block) { 1591 if (badCFG) 1592 return 0; 1593 LoopSuccessor = Block; 1594 Block = 0; 1595 } else 1596 LoopSuccessor = Succ; 1597 1598 // Build the condition blocks. 1599 CFGBlock* ExitConditionBlock = createBlock(false); 1600 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1601 1602 // Set the terminator for the "exit" condition block. 1603 ExitConditionBlock->setTerminator(S); 1604 1605 // The last statement in the block should be the ObjCForCollectionStmt, which 1606 // performs the actual binding to 'element' and determines if there are any 1607 // more items in the collection. 1608 AppendStmt(ExitConditionBlock, S); 1609 Block = ExitConditionBlock; 1610 1611 // Walk the 'element' expression to see if there are any side-effects. We 1612 // generate new blocks as necesary. We DON'T add the statement by default to 1613 // the CFG unless it contains control-flow. 1614 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1615 if (Block) { 1616 if (badCFG) 1617 return 0; 1618 Block = 0; 1619 } 1620 1621 // The condition block is the implicit successor for the loop body as well as 1622 // any code above the loop. 1623 Succ = EntryConditionBlock; 1624 1625 // Now create the true branch. 1626 { 1627 // Save the current values for Succ, continue and break targets. 1628 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1629 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1630 save_break(BreakJumpTarget); 1631 1632 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1633 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1634 1635 CFGBlock* BodyBlock = addStmt(S->getBody()); 1636 1637 if (!BodyBlock) 1638 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1639 else if (Block) { 1640 if (badCFG) 1641 return 0; 1642 } 1643 1644 // This new body block is a successor to our "exit" condition block. 1645 AddSuccessor(ExitConditionBlock, BodyBlock); 1646 } 1647 1648 // Link up the condition block with the code that follows the loop. 1649 // (the false branch). 1650 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1651 1652 // Now create a prologue block to contain the collection expression. 1653 Block = createBlock(); 1654 return addStmt(S->getCollection()); 1655} 1656 1657CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1658 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1659 1660 // Inline the body. 1661 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1662 1663 // The sync body starts its own basic block. This makes it a little easier 1664 // for diagnostic clients. 1665 if (SyncBlock) { 1666 if (badCFG) 1667 return 0; 1668 1669 Block = 0; 1670 Succ = SyncBlock; 1671 } 1672 1673 // Add the @synchronized to the CFG. 1674 autoCreateBlock(); 1675 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1676 1677 // Inline the sync expression. 1678 return addStmt(S->getSynchExpr()); 1679} 1680 1681CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1682 // FIXME 1683 return NYS(); 1684} 1685 1686CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1687 CFGBlock* LoopSuccessor = NULL; 1688 1689 // Save local scope position because in case of condition variable ScopePos 1690 // won't be restored when traversing AST. 1691 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1692 1693 // Create local scope for possible condition variable. 1694 // Store scope position for continue statement. 1695 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1696 if (VarDecl* VD = W->getConditionVariable()) { 1697 addLocalScopeForVarDecl(VD); 1698 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1699 } 1700 1701 // "while" is a control-flow statement. Thus we stop processing the current 1702 // block. 1703 if (Block) { 1704 if (badCFG) 1705 return 0; 1706 LoopSuccessor = Block; 1707 } else 1708 LoopSuccessor = Succ; 1709 1710 // Because of short-circuit evaluation, the condition of the loop can span 1711 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1712 // evaluate the condition. 1713 CFGBlock* ExitConditionBlock = createBlock(false); 1714 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1715 1716 // Set the terminator for the "exit" condition block. 1717 ExitConditionBlock->setTerminator(W); 1718 1719 // Now add the actual condition to the condition block. Because the condition 1720 // itself may contain control-flow, new blocks may be created. Thus we update 1721 // "Succ" after adding the condition. 1722 if (Stmt* C = W->getCond()) { 1723 Block = ExitConditionBlock; 1724 EntryConditionBlock = addStmt(C); 1725 assert(Block == EntryConditionBlock); 1726 1727 // If this block contains a condition variable, add both the condition 1728 // variable and initializer to the CFG. 1729 if (VarDecl *VD = W->getConditionVariable()) { 1730 if (Expr *Init = VD->getInit()) { 1731 autoCreateBlock(); 1732 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1733 EntryConditionBlock = addStmt(Init); 1734 assert(Block == EntryConditionBlock); 1735 } 1736 } 1737 1738 if (Block) { 1739 if (badCFG) 1740 return 0; 1741 } 1742 } 1743 1744 // The condition block is the implicit successor for the loop body as well as 1745 // any code above the loop. 1746 Succ = EntryConditionBlock; 1747 1748 // See if this is a known constant. 1749 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1750 1751 // Process the loop body. 1752 { 1753 assert(W->getBody()); 1754 1755 // Save the current values for Block, Succ, and continue and break targets 1756 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1757 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1758 save_break(BreakJumpTarget); 1759 1760 // Create an empty block to represent the transition block for looping back 1761 // to the head of the loop. 1762 Block = 0; 1763 assert(Succ == EntryConditionBlock); 1764 Succ = createBlock(); 1765 Succ->setLoopTarget(W); 1766 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1767 1768 // All breaks should go to the code following the loop. 1769 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1770 1771 // NULL out Block to force lazy instantiation of blocks for the body. 1772 Block = NULL; 1773 1774 // Loop body should end with destructor of Condition variable (if any). 1775 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1776 1777 // If body is not a compound statement create implicit scope 1778 // and add destructors. 1779 if (!isa<CompoundStmt>(W->getBody())) 1780 addLocalScopeAndDtors(W->getBody()); 1781 1782 // Create the body. The returned block is the entry to the loop body. 1783 CFGBlock* BodyBlock = addStmt(W->getBody()); 1784 1785 if (!BodyBlock) 1786 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1787 else if (Block) { 1788 if (badCFG) 1789 return 0; 1790 } 1791 1792 // Add the loop body entry as a successor to the condition. 1793 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1794 } 1795 1796 // Link up the condition block with the code that follows the loop. (the 1797 // false branch). 1798 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1799 1800 // There can be no more statements in the condition block since we loop back 1801 // to this block. NULL out Block to force lazy creation of another block. 1802 Block = NULL; 1803 1804 // Return the condition block, which is the dominating block for the loop. 1805 Succ = EntryConditionBlock; 1806 return EntryConditionBlock; 1807} 1808 1809 1810CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1811 // FIXME: For now we pretend that @catch and the code it contains does not 1812 // exit. 1813 return Block; 1814} 1815 1816CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1817 // FIXME: This isn't complete. We basically treat @throw like a return 1818 // statement. 1819 1820 // If we were in the middle of a block we stop processing that block. 1821 if (badCFG) 1822 return 0; 1823 1824 // Create the new block. 1825 Block = createBlock(false); 1826 1827 // The Exit block is the only successor. 1828 AddSuccessor(Block, &cfg->getExit()); 1829 1830 // Add the statement to the block. This may create new blocks if S contains 1831 // control-flow (short-circuit operations). 1832 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1833} 1834 1835CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1836 // If we were in the middle of a block we stop processing that block. 1837 if (badCFG) 1838 return 0; 1839 1840 // Create the new block. 1841 Block = createBlock(false); 1842 1843 if (TryTerminatedBlock) 1844 // The current try statement is the only successor. 1845 AddSuccessor(Block, TryTerminatedBlock); 1846 else 1847 // otherwise the Exit block is the only successor. 1848 AddSuccessor(Block, &cfg->getExit()); 1849 1850 // Add the statement to the block. This may create new blocks if S contains 1851 // control-flow (short-circuit operations). 1852 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1853} 1854 1855CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1856 CFGBlock* LoopSuccessor = NULL; 1857 1858 // "do...while" is a control-flow statement. Thus we stop processing the 1859 // current block. 1860 if (Block) { 1861 if (badCFG) 1862 return 0; 1863 LoopSuccessor = Block; 1864 } else 1865 LoopSuccessor = Succ; 1866 1867 // Because of short-circuit evaluation, the condition of the loop can span 1868 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1869 // evaluate the condition. 1870 CFGBlock* ExitConditionBlock = createBlock(false); 1871 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1872 1873 // Set the terminator for the "exit" condition block. 1874 ExitConditionBlock->setTerminator(D); 1875 1876 // Now add the actual condition to the condition block. Because the condition 1877 // itself may contain control-flow, new blocks may be created. 1878 if (Stmt* C = D->getCond()) { 1879 Block = ExitConditionBlock; 1880 EntryConditionBlock = addStmt(C); 1881 if (Block) { 1882 if (badCFG) 1883 return 0; 1884 } 1885 } 1886 1887 // The condition block is the implicit successor for the loop body. 1888 Succ = EntryConditionBlock; 1889 1890 // See if this is a known constant. 1891 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1892 1893 // Process the loop body. 1894 CFGBlock* BodyBlock = NULL; 1895 { 1896 assert(D->getBody()); 1897 1898 // Save the current values for Block, Succ, and continue and break targets 1899 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1900 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1901 save_break(BreakJumpTarget); 1902 1903 // All continues within this loop should go to the condition block 1904 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1905 1906 // All breaks should go to the code following the loop. 1907 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1908 1909 // NULL out Block to force lazy instantiation of blocks for the body. 1910 Block = NULL; 1911 1912 // If body is not a compound statement create implicit scope 1913 // and add destructors. 1914 if (!isa<CompoundStmt>(D->getBody())) 1915 addLocalScopeAndDtors(D->getBody()); 1916 1917 // Create the body. The returned block is the entry to the loop body. 1918 BodyBlock = addStmt(D->getBody()); 1919 1920 if (!BodyBlock) 1921 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1922 else if (Block) { 1923 if (badCFG) 1924 return 0; 1925 } 1926 1927 if (!KnownVal.isFalse()) { 1928 // Add an intermediate block between the BodyBlock and the 1929 // ExitConditionBlock to represent the "loop back" transition. Create an 1930 // empty block to represent the transition block for looping back to the 1931 // head of the loop. 1932 // FIXME: Can we do this more efficiently without adding another block? 1933 Block = NULL; 1934 Succ = BodyBlock; 1935 CFGBlock *LoopBackBlock = createBlock(); 1936 LoopBackBlock->setLoopTarget(D); 1937 1938 // Add the loop body entry as a successor to the condition. 1939 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1940 } 1941 else 1942 AddSuccessor(ExitConditionBlock, NULL); 1943 } 1944 1945 // Link up the condition block with the code that follows the loop. 1946 // (the false branch). 1947 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1948 1949 // There can be no more statements in the body block(s) since we loop back to 1950 // the body. NULL out Block to force lazy creation of another block. 1951 Block = NULL; 1952 1953 // Return the loop body, which is the dominating block for the loop. 1954 Succ = BodyBlock; 1955 return BodyBlock; 1956} 1957 1958CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1959 // "continue" is a control-flow statement. Thus we stop processing the 1960 // current block. 1961 if (badCFG) 1962 return 0; 1963 1964 // Now create a new block that ends with the continue statement. 1965 Block = createBlock(false); 1966 Block->setTerminator(C); 1967 1968 // If there is no target for the continue, then we are looking at an 1969 // incomplete AST. This means the CFG cannot be constructed. 1970 if (ContinueJumpTarget.Block) { 1971 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1972 AddSuccessor(Block, ContinueJumpTarget.Block); 1973 } else 1974 badCFG = true; 1975 1976 return Block; 1977} 1978 1979CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1980 AddStmtChoice asc) { 1981 1982 if (asc.alwaysAdd()) { 1983 autoCreateBlock(); 1984 AppendStmt(Block, E); 1985 } 1986 1987 // VLA types have expressions that must be evaluated. 1988 if (E->isArgumentType()) { 1989 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1990 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1991 addStmt(VA->getSizeExpr()); 1992 } 1993 1994 return Block; 1995} 1996 1997/// VisitStmtExpr - Utility method to handle (nested) statement 1998/// expressions (a GCC extension). 1999CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2000 if (asc.alwaysAdd()) { 2001 autoCreateBlock(); 2002 AppendStmt(Block, SE); 2003 } 2004 return VisitCompoundStmt(SE->getSubStmt()); 2005} 2006 2007CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2008 // "switch" is a control-flow statement. Thus we stop processing the current 2009 // block. 2010 CFGBlock* SwitchSuccessor = NULL; 2011 2012 // Save local scope position because in case of condition variable ScopePos 2013 // won't be restored when traversing AST. 2014 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2015 2016 // Create local scope for possible condition variable. 2017 // Store scope position. Add implicit destructor. 2018 if (VarDecl* VD = Terminator->getConditionVariable()) { 2019 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2020 addLocalScopeForVarDecl(VD); 2021 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2022 } 2023 2024 if (Block) { 2025 if (badCFG) 2026 return 0; 2027 SwitchSuccessor = Block; 2028 } else SwitchSuccessor = Succ; 2029 2030 // Save the current "switch" context. 2031 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2032 save_default(DefaultCaseBlock); 2033 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2034 2035 // Set the "default" case to be the block after the switch statement. If the 2036 // switch statement contains a "default:", this value will be overwritten with 2037 // the block for that code. 2038 DefaultCaseBlock = SwitchSuccessor; 2039 2040 // Create a new block that will contain the switch statement. 2041 SwitchTerminatedBlock = createBlock(false); 2042 2043 // Now process the switch body. The code after the switch is the implicit 2044 // successor. 2045 Succ = SwitchSuccessor; 2046 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2047 2048 // When visiting the body, the case statements should automatically get linked 2049 // up to the switch. We also don't keep a pointer to the body, since all 2050 // control-flow from the switch goes to case/default statements. 2051 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2052 Block = NULL; 2053 2054 // If body is not a compound statement create implicit scope 2055 // and add destructors. 2056 if (!isa<CompoundStmt>(Terminator->getBody())) 2057 addLocalScopeAndDtors(Terminator->getBody()); 2058 2059 addStmt(Terminator->getBody()); 2060 if (Block) { 2061 if (badCFG) 2062 return 0; 2063 } 2064 2065 // If we have no "default:" case, the default transition is to the code 2066 // following the switch body. 2067 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2068 2069 // Add the terminator and condition in the switch block. 2070 SwitchTerminatedBlock->setTerminator(Terminator); 2071 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2072 Block = SwitchTerminatedBlock; 2073 Block = addStmt(Terminator->getCond()); 2074 2075 // Finally, if the SwitchStmt contains a condition variable, add both the 2076 // SwitchStmt and the condition variable initialization to the CFG. 2077 if (VarDecl *VD = Terminator->getConditionVariable()) { 2078 if (Expr *Init = VD->getInit()) { 2079 autoCreateBlock(); 2080 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2081 addStmt(Init); 2082 } 2083 } 2084 2085 return Block; 2086} 2087 2088CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2089 // CaseStmts are essentially labels, so they are the first statement in a 2090 // block. 2091 CFGBlock *TopBlock = 0, *LastBlock = 0; 2092 2093 if (Stmt *Sub = CS->getSubStmt()) { 2094 // For deeply nested chains of CaseStmts, instead of doing a recursion 2095 // (which can blow out the stack), manually unroll and create blocks 2096 // along the way. 2097 while (isa<CaseStmt>(Sub)) { 2098 CFGBlock *CurrentBlock = createBlock(false); 2099 CurrentBlock->setLabel(CS); 2100 2101 if (TopBlock) 2102 AddSuccessor(LastBlock, CurrentBlock); 2103 else 2104 TopBlock = CurrentBlock; 2105 2106 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2107 LastBlock = CurrentBlock; 2108 2109 CS = cast<CaseStmt>(Sub); 2110 Sub = CS->getSubStmt(); 2111 } 2112 2113 addStmt(Sub); 2114 } 2115 2116 CFGBlock* CaseBlock = Block; 2117 if (!CaseBlock) 2118 CaseBlock = createBlock(); 2119 2120 // Cases statements partition blocks, so this is the top of the basic block we 2121 // were processing (the "case XXX:" is the label). 2122 CaseBlock->setLabel(CS); 2123 2124 if (badCFG) 2125 return 0; 2126 2127 // Add this block to the list of successors for the block with the switch 2128 // statement. 2129 assert(SwitchTerminatedBlock); 2130 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2131 2132 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2133 Block = NULL; 2134 2135 if (TopBlock) { 2136 AddSuccessor(LastBlock, CaseBlock); 2137 Succ = TopBlock; 2138 } 2139 else { 2140 // This block is now the implicit successor of other blocks. 2141 Succ = CaseBlock; 2142 } 2143 2144 return Succ; 2145} 2146 2147CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2148 if (Terminator->getSubStmt()) 2149 addStmt(Terminator->getSubStmt()); 2150 2151 DefaultCaseBlock = Block; 2152 2153 if (!DefaultCaseBlock) 2154 DefaultCaseBlock = createBlock(); 2155 2156 // Default statements partition blocks, so this is the top of the basic block 2157 // we were processing (the "default:" is the label). 2158 DefaultCaseBlock->setLabel(Terminator); 2159 2160 if (badCFG) 2161 return 0; 2162 2163 // Unlike case statements, we don't add the default block to the successors 2164 // for the switch statement immediately. This is done when we finish 2165 // processing the switch statement. This allows for the default case 2166 // (including a fall-through to the code after the switch statement) to always 2167 // be the last successor of a switch-terminated block. 2168 2169 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2170 Block = NULL; 2171 2172 // This block is now the implicit successor of other blocks. 2173 Succ = DefaultCaseBlock; 2174 2175 return DefaultCaseBlock; 2176} 2177 2178CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2179 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2180 // current block. 2181 CFGBlock* TrySuccessor = NULL; 2182 2183 if (Block) { 2184 if (badCFG) 2185 return 0; 2186 TrySuccessor = Block; 2187 } else TrySuccessor = Succ; 2188 2189 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2190 2191 // Create a new block that will contain the try statement. 2192 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2193 // Add the terminator in the try block. 2194 NewTryTerminatedBlock->setTerminator(Terminator); 2195 2196 bool HasCatchAll = false; 2197 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2198 // The code after the try is the implicit successor. 2199 Succ = TrySuccessor; 2200 CXXCatchStmt *CS = Terminator->getHandler(h); 2201 if (CS->getExceptionDecl() == 0) { 2202 HasCatchAll = true; 2203 } 2204 Block = NULL; 2205 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2206 if (CatchBlock == 0) 2207 return 0; 2208 // Add this block to the list of successors for the block with the try 2209 // statement. 2210 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2211 } 2212 if (!HasCatchAll) { 2213 if (PrevTryTerminatedBlock) 2214 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2215 else 2216 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2217 } 2218 2219 // The code after the try is the implicit successor. 2220 Succ = TrySuccessor; 2221 2222 // Save the current "try" context. 2223 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2224 TryTerminatedBlock = NewTryTerminatedBlock; 2225 2226 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2227 Block = NULL; 2228 Block = addStmt(Terminator->getTryBlock()); 2229 return Block; 2230} 2231 2232CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2233 // CXXCatchStmt are treated like labels, so they are the first statement in a 2234 // block. 2235 2236 // Save local scope position because in case of exception variable ScopePos 2237 // won't be restored when traversing AST. 2238 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2239 2240 // Create local scope for possible exception variable. 2241 // Store scope position. Add implicit destructor. 2242 if (VarDecl* VD = CS->getExceptionDecl()) { 2243 LocalScope::const_iterator BeginScopePos = ScopePos; 2244 addLocalScopeForVarDecl(VD); 2245 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2246 } 2247 2248 if (CS->getHandlerBlock()) 2249 addStmt(CS->getHandlerBlock()); 2250 2251 CFGBlock* CatchBlock = Block; 2252 if (!CatchBlock) 2253 CatchBlock = createBlock(); 2254 2255 CatchBlock->setLabel(CS); 2256 2257 if (badCFG) 2258 return 0; 2259 2260 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2261 Block = NULL; 2262 2263 return CatchBlock; 2264} 2265 2266CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2267 AddStmtChoice asc) { 2268 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2269 : AddStmtChoice::AlwaysAdd; 2270 autoCreateBlock(); 2271 AppendStmt(Block, C, AddStmtChoice(K)); 2272 return VisitChildren(C); 2273} 2274 2275CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2276 // Lazily create the indirect-goto dispatch block if there isn't one already. 2277 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2278 2279 if (!IBlock) { 2280 IBlock = createBlock(false); 2281 cfg->setIndirectGotoBlock(IBlock); 2282 } 2283 2284 // IndirectGoto is a control-flow statement. Thus we stop processing the 2285 // current block and create a new one. 2286 if (badCFG) 2287 return 0; 2288 2289 Block = createBlock(false); 2290 Block->setTerminator(I); 2291 AddSuccessor(Block, IBlock); 2292 return addStmt(I->getTarget()); 2293} 2294 2295} // end anonymous namespace 2296 2297/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2298/// no successors or predecessors. If this is the first block created in the 2299/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2300CFGBlock* CFG::createBlock() { 2301 bool first_block = begin() == end(); 2302 2303 // Create the block. 2304 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2305 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2306 Blocks.push_back(Mem, BlkBVC); 2307 2308 // If this is the first block, set it as the Entry and Exit. 2309 if (first_block) 2310 Entry = Exit = &back(); 2311 2312 // Return the block. 2313 return &back(); 2314} 2315 2316/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2317/// CFG is returned to the caller. 2318CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2319 BuildOptions BO) { 2320 CFGBuilder Builder; 2321 return Builder.buildCFG(D, Statement, C, BO); 2322} 2323 2324//===----------------------------------------------------------------------===// 2325// CFG: Queries for BlkExprs. 2326//===----------------------------------------------------------------------===// 2327 2328namespace { 2329 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2330} 2331 2332static void FindSubExprAssignments(Stmt *S, 2333 llvm::SmallPtrSet<Expr*,50>& Set) { 2334 if (!S) 2335 return; 2336 2337 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2338 Stmt *child = *I; 2339 if (!child) 2340 continue; 2341 2342 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2343 if (B->isAssignmentOp()) Set.insert(B); 2344 2345 FindSubExprAssignments(child, Set); 2346 } 2347} 2348 2349static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2350 BlkExprMapTy* M = new BlkExprMapTy(); 2351 2352 // Look for assignments that are used as subexpressions. These are the only 2353 // assignments that we want to *possibly* register as a block-level 2354 // expression. Basically, if an assignment occurs both in a subexpression and 2355 // at the block-level, it is a block-level expression. 2356 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2357 2358 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2359 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2360 if (CFGStmt S = BI->getAs<CFGStmt>()) 2361 FindSubExprAssignments(S, SubExprAssignments); 2362 2363 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2364 2365 // Iterate over the statements again on identify the Expr* and Stmt* at the 2366 // block-level that are block-level expressions. 2367 2368 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2369 CFGStmt CS = BI->getAs<CFGStmt>(); 2370 if (!CS.isValid()) 2371 continue; 2372 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2373 2374 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2375 // Assignment expressions that are not nested within another 2376 // expression are really "statements" whose value is never used by 2377 // another expression. 2378 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2379 continue; 2380 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2381 // Special handling for statement expressions. The last statement in 2382 // the statement expression is also a block-level expr. 2383 const CompoundStmt* C = Terminator->getSubStmt(); 2384 if (!C->body_empty()) { 2385 unsigned x = M->size(); 2386 (*M)[C->body_back()] = x; 2387 } 2388 } 2389 2390 unsigned x = M->size(); 2391 (*M)[Exp] = x; 2392 } 2393 } 2394 2395 // Look at terminators. The condition is a block-level expression. 2396 2397 Stmt* S = (*I)->getTerminatorCondition(); 2398 2399 if (S && M->find(S) == M->end()) { 2400 unsigned x = M->size(); 2401 (*M)[S] = x; 2402 } 2403 } 2404 2405 return M; 2406} 2407 2408CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2409 assert(S != NULL); 2410 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2411 2412 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2413 BlkExprMapTy::iterator I = M->find(S); 2414 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2415} 2416 2417unsigned CFG::getNumBlkExprs() { 2418 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2419 return M->size(); 2420 else { 2421 // We assume callers interested in the number of BlkExprs will want 2422 // the map constructed if it doesn't already exist. 2423 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2424 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2425 } 2426} 2427 2428//===----------------------------------------------------------------------===// 2429// Filtered walking of the CFG. 2430//===----------------------------------------------------------------------===// 2431 2432bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2433 const CFGBlock *From, const CFGBlock *To) { 2434 2435 if (F.IgnoreDefaultsWithCoveredEnums) { 2436 // If the 'To' has no label or is labeled but the label isn't a 2437 // CaseStmt then filter this edge. 2438 if (const SwitchStmt *S = 2439 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2440 if (S->isAllEnumCasesCovered()) { 2441 const Stmt *L = To->getLabel(); 2442 if (!L || !isa<CaseStmt>(L)) 2443 return true; 2444 } 2445 } 2446 } 2447 2448 return false; 2449} 2450 2451//===----------------------------------------------------------------------===// 2452// Cleanup: CFG dstor. 2453//===----------------------------------------------------------------------===// 2454 2455CFG::~CFG() { 2456 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2457} 2458 2459//===----------------------------------------------------------------------===// 2460// CFG pretty printing 2461//===----------------------------------------------------------------------===// 2462 2463namespace { 2464 2465class StmtPrinterHelper : public PrinterHelper { 2466 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2467 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2468 StmtMapTy StmtMap; 2469 DeclMapTy DeclMap; 2470 signed CurrentBlock; 2471 unsigned CurrentStmt; 2472 const LangOptions &LangOpts; 2473public: 2474 2475 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2476 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2477 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2478 unsigned j = 1; 2479 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2480 BI != BEnd; ++BI, ++j ) { 2481 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2482 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2483 StmtMap[SE] = P; 2484 2485 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2486 DeclMap[DS->getSingleDecl()] = P; 2487 2488 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2489 if (VarDecl* VD = IS->getConditionVariable()) 2490 DeclMap[VD] = P; 2491 2492 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2493 if (VarDecl* VD = FS->getConditionVariable()) 2494 DeclMap[VD] = P; 2495 2496 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2497 if (VarDecl* VD = WS->getConditionVariable()) 2498 DeclMap[VD] = P; 2499 2500 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2501 if (VarDecl* VD = SS->getConditionVariable()) 2502 DeclMap[VD] = P; 2503 2504 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2505 if (VarDecl* VD = CS->getExceptionDecl()) 2506 DeclMap[VD] = P; 2507 } 2508 } 2509 } 2510 } 2511 } 2512 2513 virtual ~StmtPrinterHelper() {} 2514 2515 const LangOptions &getLangOpts() const { return LangOpts; } 2516 void setBlockID(signed i) { CurrentBlock = i; } 2517 void setStmtID(unsigned i) { CurrentStmt = i; } 2518 2519 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2520 StmtMapTy::iterator I = StmtMap.find(S); 2521 2522 if (I == StmtMap.end()) 2523 return false; 2524 2525 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2526 && I->second.second == CurrentStmt) { 2527 return false; 2528 } 2529 2530 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2531 return true; 2532 } 2533 2534 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2535 DeclMapTy::iterator I = DeclMap.find(D); 2536 2537 if (I == DeclMap.end()) 2538 return false; 2539 2540 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2541 && I->second.second == CurrentStmt) { 2542 return false; 2543 } 2544 2545 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2546 return true; 2547 } 2548}; 2549} // end anonymous namespace 2550 2551 2552namespace { 2553class CFGBlockTerminatorPrint 2554 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2555 2556 llvm::raw_ostream& OS; 2557 StmtPrinterHelper* Helper; 2558 PrintingPolicy Policy; 2559public: 2560 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2561 const PrintingPolicy &Policy) 2562 : OS(os), Helper(helper), Policy(Policy) {} 2563 2564 void VisitIfStmt(IfStmt* I) { 2565 OS << "if "; 2566 I->getCond()->printPretty(OS,Helper,Policy); 2567 } 2568 2569 // Default case. 2570 void VisitStmt(Stmt* Terminator) { 2571 Terminator->printPretty(OS, Helper, Policy); 2572 } 2573 2574 void VisitForStmt(ForStmt* F) { 2575 OS << "for (" ; 2576 if (F->getInit()) 2577 OS << "..."; 2578 OS << "; "; 2579 if (Stmt* C = F->getCond()) 2580 C->printPretty(OS, Helper, Policy); 2581 OS << "; "; 2582 if (F->getInc()) 2583 OS << "..."; 2584 OS << ")"; 2585 } 2586 2587 void VisitWhileStmt(WhileStmt* W) { 2588 OS << "while " ; 2589 if (Stmt* C = W->getCond()) 2590 C->printPretty(OS, Helper, Policy); 2591 } 2592 2593 void VisitDoStmt(DoStmt* D) { 2594 OS << "do ... while "; 2595 if (Stmt* C = D->getCond()) 2596 C->printPretty(OS, Helper, Policy); 2597 } 2598 2599 void VisitSwitchStmt(SwitchStmt* Terminator) { 2600 OS << "switch "; 2601 Terminator->getCond()->printPretty(OS, Helper, Policy); 2602 } 2603 2604 void VisitCXXTryStmt(CXXTryStmt* CS) { 2605 OS << "try ..."; 2606 } 2607 2608 void VisitConditionalOperator(ConditionalOperator* C) { 2609 C->getCond()->printPretty(OS, Helper, Policy); 2610 OS << " ? ... : ..."; 2611 } 2612 2613 void VisitChooseExpr(ChooseExpr* C) { 2614 OS << "__builtin_choose_expr( "; 2615 C->getCond()->printPretty(OS, Helper, Policy); 2616 OS << " )"; 2617 } 2618 2619 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2620 OS << "goto *"; 2621 I->getTarget()->printPretty(OS, Helper, Policy); 2622 } 2623 2624 void VisitBinaryOperator(BinaryOperator* B) { 2625 if (!B->isLogicalOp()) { 2626 VisitExpr(B); 2627 return; 2628 } 2629 2630 B->getLHS()->printPretty(OS, Helper, Policy); 2631 2632 switch (B->getOpcode()) { 2633 case BO_LOr: 2634 OS << " || ..."; 2635 return; 2636 case BO_LAnd: 2637 OS << " && ..."; 2638 return; 2639 default: 2640 assert(false && "Invalid logical operator."); 2641 } 2642 } 2643 2644 void VisitExpr(Expr* E) { 2645 E->printPretty(OS, Helper, Policy); 2646 } 2647}; 2648} // end anonymous namespace 2649 2650static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2651 const CFGElement &E) { 2652 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2653 Stmt *S = CS; 2654 2655 if (Helper) { 2656 2657 // special printing for statement-expressions. 2658 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2659 CompoundStmt* Sub = SE->getSubStmt(); 2660 2661 if (Sub->child_begin() != Sub->child_end()) { 2662 OS << "({ ... ; "; 2663 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2664 OS << " })\n"; 2665 return; 2666 } 2667 } 2668 // special printing for comma expressions. 2669 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2670 if (B->getOpcode() == BO_Comma) { 2671 OS << "... , "; 2672 Helper->handledStmt(B->getRHS(),OS); 2673 OS << '\n'; 2674 return; 2675 } 2676 } 2677 } 2678 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2679 2680 if (isa<CXXOperatorCallExpr>(S)) { 2681 OS << " (OperatorCall)"; 2682 } 2683 else if (isa<CXXBindTemporaryExpr>(S)) { 2684 OS << " (BindTemporary)"; 2685 } 2686 2687 // Expressions need a newline. 2688 if (isa<Expr>(S)) 2689 OS << '\n'; 2690 2691 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2692 CXXBaseOrMemberInitializer* I = IE; 2693 if (I->isBaseInitializer()) 2694 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2695 else OS << I->getMember()->getName(); 2696 2697 OS << "("; 2698 if (Expr* IE = I->getInit()) 2699 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2700 OS << ")"; 2701 2702 if (I->isBaseInitializer()) 2703 OS << " (Base initializer)\n"; 2704 else OS << " (Member initializer)\n"; 2705 2706 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2707 VarDecl* VD = DE.getVarDecl(); 2708 Helper->handleDecl(VD, OS); 2709 2710 Type* T = VD->getType().getTypePtr(); 2711 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2712 T = RT->getPointeeType().getTypePtr(); 2713 2714 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2715 OS << " (Implicit destructor)\n"; 2716 2717 } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { 2718 const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); 2719 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 2720 OS << " (Base object destructor)\n"; 2721 2722 } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { 2723 FieldDecl *FD = ME.getFieldDecl(); 2724 OS << "this->" << FD->getName(); 2725 OS << ".~" << FD->getType()->getAsCXXRecordDecl()->getName() << "()"; 2726 OS << " (Member object destructor)\n"; 2727 } 2728 } 2729 2730static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2731 const CFGBlock& B, 2732 StmtPrinterHelper* Helper, bool print_edges) { 2733 2734 if (Helper) Helper->setBlockID(B.getBlockID()); 2735 2736 // Print the header. 2737 OS << "\n [ B" << B.getBlockID(); 2738 2739 if (&B == &cfg->getEntry()) 2740 OS << " (ENTRY) ]\n"; 2741 else if (&B == &cfg->getExit()) 2742 OS << " (EXIT) ]\n"; 2743 else if (&B == cfg->getIndirectGotoBlock()) 2744 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2745 else 2746 OS << " ]\n"; 2747 2748 // Print the label of this block. 2749 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2750 2751 if (print_edges) 2752 OS << " "; 2753 2754 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2755 OS << L->getName(); 2756 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2757 OS << "case "; 2758 C->getLHS()->printPretty(OS, Helper, 2759 PrintingPolicy(Helper->getLangOpts())); 2760 if (C->getRHS()) { 2761 OS << " ... "; 2762 C->getRHS()->printPretty(OS, Helper, 2763 PrintingPolicy(Helper->getLangOpts())); 2764 } 2765 } else if (isa<DefaultStmt>(Label)) 2766 OS << "default"; 2767 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2768 OS << "catch ("; 2769 if (CS->getExceptionDecl()) 2770 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2771 0); 2772 else 2773 OS << "..."; 2774 OS << ")"; 2775 2776 } else 2777 assert(false && "Invalid label statement in CFGBlock."); 2778 2779 OS << ":\n"; 2780 } 2781 2782 // Iterate through the statements in the block and print them. 2783 unsigned j = 1; 2784 2785 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2786 I != E ; ++I, ++j ) { 2787 2788 // Print the statement # in the basic block and the statement itself. 2789 if (print_edges) 2790 OS << " "; 2791 2792 OS << llvm::format("%3d", j) << ": "; 2793 2794 if (Helper) 2795 Helper->setStmtID(j); 2796 2797 print_elem(OS,Helper,*I); 2798 } 2799 2800 // Print the terminator of this block. 2801 if (B.getTerminator()) { 2802 if (print_edges) 2803 OS << " "; 2804 2805 OS << " T: "; 2806 2807 if (Helper) Helper->setBlockID(-1); 2808 2809 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2810 PrintingPolicy(Helper->getLangOpts())); 2811 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2812 OS << '\n'; 2813 } 2814 2815 if (print_edges) { 2816 // Print the predecessors of this block. 2817 OS << " Predecessors (" << B.pred_size() << "):"; 2818 unsigned i = 0; 2819 2820 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2821 I != E; ++I, ++i) { 2822 2823 if (i == 8 || (i-8) == 0) 2824 OS << "\n "; 2825 2826 OS << " B" << (*I)->getBlockID(); 2827 } 2828 2829 OS << '\n'; 2830 2831 // Print the successors of this block. 2832 OS << " Successors (" << B.succ_size() << "):"; 2833 i = 0; 2834 2835 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2836 I != E; ++I, ++i) { 2837 2838 if (i == 8 || (i-8) % 10 == 0) 2839 OS << "\n "; 2840 2841 if (*I) 2842 OS << " B" << (*I)->getBlockID(); 2843 else 2844 OS << " NULL"; 2845 } 2846 2847 OS << '\n'; 2848 } 2849} 2850 2851 2852/// dump - A simple pretty printer of a CFG that outputs to stderr. 2853void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2854 2855/// print - A simple pretty printer of a CFG that outputs to an ostream. 2856void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2857 StmtPrinterHelper Helper(this, LO); 2858 2859 // Print the entry block. 2860 print_block(OS, this, getEntry(), &Helper, true); 2861 2862 // Iterate through the CFGBlocks and print them one by one. 2863 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2864 // Skip the entry block, because we already printed it. 2865 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2866 continue; 2867 2868 print_block(OS, this, **I, &Helper, true); 2869 } 2870 2871 // Print the exit block. 2872 print_block(OS, this, getExit(), &Helper, true); 2873 OS.flush(); 2874} 2875 2876/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2877void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2878 print(llvm::errs(), cfg, LO); 2879} 2880 2881/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2882/// Generally this will only be called from CFG::print. 2883void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2884 const LangOptions &LO) const { 2885 StmtPrinterHelper Helper(cfg, LO); 2886 print_block(OS, cfg, *this, &Helper, true); 2887} 2888 2889/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2890void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2891 const LangOptions &LO) const { 2892 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2893 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2894} 2895 2896Stmt* CFGBlock::getTerminatorCondition() { 2897 2898 if (!Terminator) 2899 return NULL; 2900 2901 Expr* E = NULL; 2902 2903 switch (Terminator->getStmtClass()) { 2904 default: 2905 break; 2906 2907 case Stmt::ForStmtClass: 2908 E = cast<ForStmt>(Terminator)->getCond(); 2909 break; 2910 2911 case Stmt::WhileStmtClass: 2912 E = cast<WhileStmt>(Terminator)->getCond(); 2913 break; 2914 2915 case Stmt::DoStmtClass: 2916 E = cast<DoStmt>(Terminator)->getCond(); 2917 break; 2918 2919 case Stmt::IfStmtClass: 2920 E = cast<IfStmt>(Terminator)->getCond(); 2921 break; 2922 2923 case Stmt::ChooseExprClass: 2924 E = cast<ChooseExpr>(Terminator)->getCond(); 2925 break; 2926 2927 case Stmt::IndirectGotoStmtClass: 2928 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2929 break; 2930 2931 case Stmt::SwitchStmtClass: 2932 E = cast<SwitchStmt>(Terminator)->getCond(); 2933 break; 2934 2935 case Stmt::ConditionalOperatorClass: 2936 E = cast<ConditionalOperator>(Terminator)->getCond(); 2937 break; 2938 2939 case Stmt::BinaryOperatorClass: // '&&' and '||' 2940 E = cast<BinaryOperator>(Terminator)->getLHS(); 2941 break; 2942 2943 case Stmt::ObjCForCollectionStmtClass: 2944 return Terminator; 2945 } 2946 2947 return E ? E->IgnoreParens() : NULL; 2948} 2949 2950bool CFGBlock::hasBinaryBranchTerminator() const { 2951 2952 if (!Terminator) 2953 return false; 2954 2955 Expr* E = NULL; 2956 2957 switch (Terminator->getStmtClass()) { 2958 default: 2959 return false; 2960 2961 case Stmt::ForStmtClass: 2962 case Stmt::WhileStmtClass: 2963 case Stmt::DoStmtClass: 2964 case Stmt::IfStmtClass: 2965 case Stmt::ChooseExprClass: 2966 case Stmt::ConditionalOperatorClass: 2967 case Stmt::BinaryOperatorClass: 2968 return true; 2969 } 2970 2971 return E ? E->IgnoreParens() : NULL; 2972} 2973 2974 2975//===----------------------------------------------------------------------===// 2976// CFG Graphviz Visualization 2977//===----------------------------------------------------------------------===// 2978 2979 2980#ifndef NDEBUG 2981static StmtPrinterHelper* GraphHelper; 2982#endif 2983 2984void CFG::viewCFG(const LangOptions &LO) const { 2985#ifndef NDEBUG 2986 StmtPrinterHelper H(this, LO); 2987 GraphHelper = &H; 2988 llvm::ViewGraph(this,"CFG"); 2989 GraphHelper = NULL; 2990#endif 2991} 2992 2993namespace llvm { 2994template<> 2995struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2996 2997 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2998 2999 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3000 3001#ifndef NDEBUG 3002 std::string OutSStr; 3003 llvm::raw_string_ostream Out(OutSStr); 3004 print_block(Out,Graph, *Node, GraphHelper, false); 3005 std::string& OutStr = Out.str(); 3006 3007 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3008 3009 // Process string output to make it nicer... 3010 for (unsigned i = 0; i != OutStr.length(); ++i) 3011 if (OutStr[i] == '\n') { // Left justify 3012 OutStr[i] = '\\'; 3013 OutStr.insert(OutStr.begin()+i+1, 'l'); 3014 } 3015 3016 return OutStr; 3017#else 3018 return ""; 3019#endif 3020 } 3021}; 3022} // end namespace llvm 3023