CFG.cpp revision 892697dd2287caf7c29aaaa82909b0e90b8b63fe
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 return D->getLocation(); 36} 37 38/// The CFG builder uses a recursive algorithm to build the CFG. When 39/// we process an expression, sometimes we know that we must add the 40/// subexpressions as block-level expressions. For example: 41/// 42/// exp1 || exp2 43/// 44/// When processing the '||' expression, we know that exp1 and exp2 45/// need to be added as block-level expressions, even though they 46/// might not normally need to be. AddStmtChoice records this 47/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 48/// the builder has an option not to add a subexpression as a 49/// block-level expression. 50/// 51class AddStmtChoice { 52public: 53 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 54 55 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 56 57 bool alwaysAdd() const { return kind & AlwaysAdd; } 58 59 /// Return a copy of this object, except with the 'always-add' bit 60 /// set as specified. 61 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 62 return AddStmtChoice(alwaysAdd ? Kind(kind | AlwaysAdd) : 63 Kind(kind & ~AlwaysAdd)); 64 } 65 66private: 67 Kind kind; 68}; 69 70/// LocalScope - Node in tree of local scopes created for C++ implicit 71/// destructor calls generation. It contains list of automatic variables 72/// declared in the scope and link to position in previous scope this scope 73/// began in. 74/// 75/// The process of creating local scopes is as follows: 76/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 77/// - Before processing statements in scope (e.g. CompoundStmt) create 78/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 79/// and set CFGBuilder::ScopePos to the end of new scope, 80/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 81/// at this VarDecl, 82/// - For every normal (without jump) end of scope add to CFGBlock destructors 83/// for objects in the current scope, 84/// - For every jump add to CFGBlock destructors for objects 85/// between CFGBuilder::ScopePos and local scope position saved for jump 86/// target. Thanks to C++ restrictions on goto jumps we can be sure that 87/// jump target position will be on the path to root from CFGBuilder::ScopePos 88/// (adding any variable that doesn't need constructor to be called to 89/// LocalScope can break this assumption), 90/// 91class LocalScope { 92public: 93 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 94 95 /// const_iterator - Iterates local scope backwards and jumps to previous 96 /// scope on reaching the beginning of currently iterated scope. 97 class const_iterator { 98 const LocalScope* Scope; 99 100 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 101 /// Invalid iterator (with null Scope) has VarIter equal to 0. 102 unsigned VarIter; 103 104 public: 105 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 106 /// Incrementing invalid iterator is allowed and will result in invalid 107 /// iterator. 108 const_iterator() 109 : Scope(NULL), VarIter(0) {} 110 111 /// Create valid iterator. In case when S.Prev is an invalid iterator and 112 /// I is equal to 0, this will create invalid iterator. 113 const_iterator(const LocalScope& S, unsigned I) 114 : Scope(&S), VarIter(I) { 115 // Iterator to "end" of scope is not allowed. Handle it by going up 116 // in scopes tree possibly up to invalid iterator in the root. 117 if (VarIter == 0 && Scope) 118 *this = Scope->Prev; 119 } 120 121 VarDecl* const* operator->() const { 122 assert (Scope && "Dereferencing invalid iterator is not allowed"); 123 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 124 return &Scope->Vars[VarIter - 1]; 125 } 126 VarDecl* operator*() const { 127 return *this->operator->(); 128 } 129 130 const_iterator& operator++() { 131 if (!Scope) 132 return *this; 133 134 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 135 --VarIter; 136 if (VarIter == 0) 137 *this = Scope->Prev; 138 return *this; 139 } 140 const_iterator operator++(int) { 141 const_iterator P = *this; 142 ++*this; 143 return P; 144 } 145 146 bool operator==(const const_iterator& rhs) const { 147 return Scope == rhs.Scope && VarIter == rhs.VarIter; 148 } 149 bool operator!=(const const_iterator& rhs) const { 150 return !(*this == rhs); 151 } 152 153 operator bool() const { 154 return *this != const_iterator(); 155 } 156 157 int distance(const_iterator L); 158 }; 159 160 friend class const_iterator; 161 162private: 163 /// Automatic variables in order of declaration. 164 AutomaticVarsTy Vars; 165 /// Iterator to variable in previous scope that was declared just before 166 /// begin of this scope. 167 const_iterator Prev; 168 169public: 170 /// Constructs empty scope linked to previous scope in specified place. 171 LocalScope(const_iterator P) 172 : Vars() 173 , Prev(P) {} 174 175 /// Begin of scope in direction of CFG building (backwards). 176 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 177 178 void addVar(VarDecl* VD) { 179 Vars.push_back(VD); 180 } 181}; 182 183/// distance - Calculates distance from this to L. L must be reachable from this 184/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 185/// number of scopes between this and L. 186int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 187 int D = 0; 188 const_iterator F = *this; 189 while (F.Scope != L.Scope) { 190 assert (F != const_iterator() 191 && "L iterator is not reachable from F iterator."); 192 D += F.VarIter; 193 F = F.Scope->Prev; 194 } 195 D += F.VarIter - L.VarIter; 196 return D; 197} 198 199/// BlockScopePosPair - Structure for specifying position in CFG during its 200/// build process. It consists of CFGBlock that specifies position in CFG graph 201/// and LocalScope::const_iterator that specifies position in LocalScope graph. 202struct BlockScopePosPair { 203 BlockScopePosPair() {} 204 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 205 : Block(B), ScopePos(S) {} 206 207 CFGBlock* Block; 208 LocalScope::const_iterator ScopePos; 209}; 210 211/// CFGBuilder - This class implements CFG construction from an AST. 212/// The builder is stateful: an instance of the builder should be used to only 213/// construct a single CFG. 214/// 215/// Example usage: 216/// 217/// CFGBuilder builder; 218/// CFG* cfg = builder.BuildAST(stmt1); 219/// 220/// CFG construction is done via a recursive walk of an AST. We actually parse 221/// the AST in reverse order so that the successor of a basic block is 222/// constructed prior to its predecessor. This allows us to nicely capture 223/// implicit fall-throughs without extra basic blocks. 224/// 225class CFGBuilder { 226 typedef BlockScopePosPair JumpTarget; 227 typedef BlockScopePosPair JumpSource; 228 229 ASTContext *Context; 230 llvm::OwningPtr<CFG> cfg; 231 232 CFGBlock* Block; 233 CFGBlock* Succ; 234 JumpTarget ContinueJumpTarget; 235 JumpTarget BreakJumpTarget; 236 CFGBlock* SwitchTerminatedBlock; 237 CFGBlock* DefaultCaseBlock; 238 CFGBlock* TryTerminatedBlock; 239 240 // Current position in local scope. 241 LocalScope::const_iterator ScopePos; 242 243 // LabelMap records the mapping from Label expressions to their jump targets. 244 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 245 LabelMapTy LabelMap; 246 247 // A list of blocks that end with a "goto" that must be backpatched to their 248 // resolved targets upon completion of CFG construction. 249 typedef std::vector<JumpSource> BackpatchBlocksTy; 250 BackpatchBlocksTy BackpatchBlocks; 251 252 // A list of labels whose address has been taken (for indirect gotos). 253 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 254 LabelSetTy AddressTakenLabels; 255 256 bool badCFG; 257 CFG::BuildOptions BuildOpts; 258 259public: 260 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 261 Block(NULL), Succ(NULL), 262 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 263 TryTerminatedBlock(NULL), badCFG(false) {} 264 265 // buildCFG - Used by external clients to construct the CFG. 266 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 267 CFG::BuildOptions BO); 268 269private: 270 // Visitors to walk an AST and construct the CFG. 271 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 272 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 273 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 274 CFGBlock *VisitBreakStmt(BreakStmt *B); 275 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 276 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 277 AddStmtChoice asc); 278 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 279 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 280 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 281 AddStmtChoice asc); 282 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 283 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 284 AddStmtChoice asc); 285 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 286 AddStmtChoice asc); 287 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 288 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 289 CFGBlock *VisitCaseStmt(CaseStmt *C); 290 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 291 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 292 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 293 CFGBlock *VisitContinueStmt(ContinueStmt *C); 294 CFGBlock *VisitDeclStmt(DeclStmt *DS); 295 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 296 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 297 CFGBlock *VisitDoStmt(DoStmt *D); 298 CFGBlock *VisitForStmt(ForStmt *F); 299 CFGBlock *VisitGotoStmt(GotoStmt* G); 300 CFGBlock *VisitIfStmt(IfStmt *I); 301 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 302 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 303 CFGBlock *VisitLabelStmt(LabelStmt *L); 304 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 305 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 306 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 307 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 308 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 309 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 310 CFGBlock *VisitReturnStmt(ReturnStmt* R); 311 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 312 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 313 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 314 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 315 CFGBlock *VisitWhileStmt(WhileStmt *W); 316 317 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 318 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 319 CFGBlock *VisitChildren(Stmt* S); 320 321 // Visitors to walk an AST and generate destructors of temporaries in 322 // full expression. 323 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 324 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 325 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 326 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 327 bool BindToTemporary); 328 CFGBlock *VisitConditionalOperatorForTemporaryDtors(ConditionalOperator *E, 329 bool BindToTemporary); 330 331 // NYS == Not Yet Supported 332 CFGBlock* NYS() { 333 badCFG = true; 334 return Block; 335 } 336 337 void autoCreateBlock() { if (!Block) Block = createBlock(); } 338 CFGBlock *createBlock(bool add_successor = true); 339 340 CFGBlock *addStmt(Stmt *S) { 341 return Visit(S, AddStmtChoice::AlwaysAdd); 342 } 343 CFGBlock *addInitializer(CXXBaseOrMemberInitializer *I); 344 void addAutomaticObjDtors(LocalScope::const_iterator B, 345 LocalScope::const_iterator E, Stmt* S); 346 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 347 348 // Local scopes creation. 349 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 350 351 void addLocalScopeForStmt(Stmt* S); 352 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 353 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 354 355 void addLocalScopeAndDtors(Stmt* S); 356 357 // Interface to CFGBlock - adding CFGElements. 358 void appendStmt(CFGBlock *B, Stmt *S, 359 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 360 B->appendStmt(S, cfg->getBumpVectorContext()); 361 } 362 void appendInitializer(CFGBlock *B, CXXBaseOrMemberInitializer *I) { 363 B->appendInitializer(I, cfg->getBumpVectorContext()); 364 } 365 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 366 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 367 } 368 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 369 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 370 } 371 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 372 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 373 } 374 375 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 376 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 377 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 378 LocalScope::const_iterator E, Stmt* S); 379 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 380 LocalScope::const_iterator B, LocalScope::const_iterator E); 381 382 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 383 B->addSuccessor(S, cfg->getBumpVectorContext()); 384 } 385 386 /// TryResult - a class representing a variant over the values 387 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 388 /// and is used by the CFGBuilder to decide if a branch condition 389 /// can be decided up front during CFG construction. 390 class TryResult { 391 int X; 392 public: 393 TryResult(bool b) : X(b ? 1 : 0) {} 394 TryResult() : X(-1) {} 395 396 bool isTrue() const { return X == 1; } 397 bool isFalse() const { return X == 0; } 398 bool isKnown() const { return X >= 0; } 399 void negate() { 400 assert(isKnown()); 401 X ^= 0x1; 402 } 403 }; 404 405 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 406 /// if we can evaluate to a known value, otherwise return -1. 407 TryResult TryEvaluateBool(Expr *S) { 408 if (!BuildOpts.PruneTriviallyFalseEdges) 409 return TryResult(); 410 411 Expr::EvalResult Result; 412 if (!S->isTypeDependent() && !S->isValueDependent() && 413 S->Evaluate(Result, *Context) && Result.Val.isInt()) 414 return Result.Val.getInt().getBoolValue(); 415 416 return TryResult(); 417 } 418}; 419 420// FIXME: Add support for dependent-sized array types in C++? 421// Does it even make sense to build a CFG for an uninstantiated template? 422static VariableArrayType* FindVA(Type* t) { 423 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 424 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 425 if (vat->getSizeExpr()) 426 return vat; 427 428 t = vt->getElementType().getTypePtr(); 429 } 430 431 return 0; 432} 433 434/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 435/// arbitrary statement. Examples include a single expression or a function 436/// body (compound statement). The ownership of the returned CFG is 437/// transferred to the caller. If CFG construction fails, this method returns 438/// NULL. 439CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 440 CFG::BuildOptions BO) { 441 442 Context = C; 443 assert(cfg.get()); 444 if (!Statement) 445 return NULL; 446 447 BuildOpts = BO; 448 449 // Create an empty block that will serve as the exit block for the CFG. Since 450 // this is the first block added to the CFG, it will be implicitly registered 451 // as the exit block. 452 Succ = createBlock(); 453 assert(Succ == &cfg->getExit()); 454 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 455 456 if (BuildOpts.AddImplicitDtors) 457 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 458 addImplicitDtorsForDestructor(DD); 459 460 // Visit the statements and create the CFG. 461 CFGBlock *B = addStmt(Statement); 462 463 if (badCFG) 464 return NULL; 465 466 // For C++ constructor add initializers to CFG. 467 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 468 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 469 E = CD->init_rend(); I != E; ++I) { 470 B = addInitializer(*I); 471 if (badCFG) 472 return NULL; 473 } 474 } 475 476 if (B) 477 Succ = B; 478 479 // Backpatch the gotos whose label -> block mappings we didn't know when we 480 // encountered them. 481 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 482 E = BackpatchBlocks.end(); I != E; ++I ) { 483 484 CFGBlock* B = I->Block; 485 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 486 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 487 488 // If there is no target for the goto, then we are looking at an 489 // incomplete AST. Handle this by not registering a successor. 490 if (LI == LabelMap.end()) continue; 491 492 JumpTarget JT = LI->second; 493 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 494 AddSuccessor(B, JT.Block); 495 } 496 497 // Add successors to the Indirect Goto Dispatch block (if we have one). 498 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 499 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 500 E = AddressTakenLabels.end(); I != E; ++I ) { 501 502 // Lookup the target block. 503 LabelMapTy::iterator LI = LabelMap.find(*I); 504 505 // If there is no target block that contains label, then we are looking 506 // at an incomplete AST. Handle this by not registering a successor. 507 if (LI == LabelMap.end()) continue; 508 509 AddSuccessor(B, LI->second.Block); 510 } 511 512 // Create an empty entry block that has no predecessors. 513 cfg->setEntry(createBlock()); 514 515 return cfg.take(); 516} 517 518/// createBlock - Used to lazily create blocks that are connected 519/// to the current (global) succcessor. 520CFGBlock* CFGBuilder::createBlock(bool add_successor) { 521 CFGBlock* B = cfg->createBlock(); 522 if (add_successor && Succ) 523 AddSuccessor(B, Succ); 524 return B; 525} 526 527/// addInitializer - Add C++ base or member initializer element to CFG. 528CFGBlock *CFGBuilder::addInitializer(CXXBaseOrMemberInitializer *I) { 529 if (!BuildOpts.AddInitializers) 530 return Block; 531 532 bool IsReference = false; 533 bool HasTemporaries = false; 534 535 // Destructors of temporaries in initialization expression should be called 536 // after initialization finishes. 537 Expr *Init = I->getInit(); 538 if (Init) { 539 if (FieldDecl *FD = I->getAnyMember()) 540 IsReference = FD->getType()->isReferenceType(); 541 HasTemporaries = isa<ExprWithCleanups>(Init); 542 543 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 544 // Generate destructors for temporaries in initialization expression. 545 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 546 IsReference); 547 } 548 } 549 550 autoCreateBlock(); 551 appendInitializer(Block, I); 552 553 if (Init) { 554 if (HasTemporaries) { 555 // For expression with temporaries go directly to subexpression to omit 556 // generating destructors for the second time. 557 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 558 } 559 return Visit(Init); 560 } 561 562 return Block; 563} 564 565/// addAutomaticObjDtors - Add to current block automatic objects destructors 566/// for objects in range of local scope positions. Use S as trigger statement 567/// for destructors. 568void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 569 LocalScope::const_iterator E, Stmt* S) { 570 if (!BuildOpts.AddImplicitDtors) 571 return; 572 573 if (B == E) 574 return; 575 576 autoCreateBlock(); 577 appendAutomaticObjDtors(Block, B, E, S); 578} 579 580/// addImplicitDtorsForDestructor - Add implicit destructors generated for 581/// base and member objects in destructor. 582void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 583 assert (BuildOpts.AddImplicitDtors 584 && "Can be called only when dtors should be added"); 585 const CXXRecordDecl *RD = DD->getParent(); 586 587 // At the end destroy virtual base objects. 588 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 589 VE = RD->vbases_end(); VI != VE; ++VI) { 590 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 591 if (!CD->hasTrivialDestructor()) { 592 autoCreateBlock(); 593 appendBaseDtor(Block, VI); 594 } 595 } 596 597 // Before virtual bases destroy direct base objects. 598 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 599 BE = RD->bases_end(); BI != BE; ++BI) { 600 if (!BI->isVirtual()) { 601 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 602 if (!CD->hasTrivialDestructor()) { 603 autoCreateBlock(); 604 appendBaseDtor(Block, BI); 605 } 606 } 607 } 608 609 // First destroy member objects. 610 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 611 FE = RD->field_end(); FI != FE; ++FI) { 612 // Check for constant size array. Set type to array element type. 613 QualType QT = FI->getType(); 614 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 615 if (AT->getSize() == 0) 616 continue; 617 QT = AT->getElementType(); 618 } 619 620 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 621 if (!CD->hasTrivialDestructor()) { 622 autoCreateBlock(); 623 appendMemberDtor(Block, *FI); 624 } 625 } 626} 627 628/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 629/// way return valid LocalScope object. 630LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 631 if (!Scope) { 632 Scope = cfg->getAllocator().Allocate<LocalScope>(); 633 new (Scope) LocalScope(ScopePos); 634 } 635 return Scope; 636} 637 638/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 639/// that should create implicit scope (e.g. if/else substatements). 640void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 641 if (!BuildOpts.AddImplicitDtors) 642 return; 643 644 LocalScope *Scope = 0; 645 646 // For compound statement we will be creating explicit scope. 647 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 648 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 649 ; BI != BE; ++BI) { 650 Stmt* SI = *BI; 651 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 652 SI = LS->getSubStmt(); 653 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 654 Scope = addLocalScopeForDeclStmt(DS, Scope); 655 } 656 return; 657 } 658 659 // For any other statement scope will be implicit and as such will be 660 // interesting only for DeclStmt. 661 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 662 S = LS->getSubStmt(); 663 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 664 addLocalScopeForDeclStmt(DS); 665} 666 667/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 668/// reuse Scope if not NULL. 669LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 670 LocalScope* Scope) { 671 if (!BuildOpts.AddImplicitDtors) 672 return Scope; 673 674 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 675 ; DI != DE; ++DI) { 676 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 677 Scope = addLocalScopeForVarDecl(VD, Scope); 678 } 679 return Scope; 680} 681 682/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 683/// create add scope for automatic objects and temporary objects bound to 684/// const reference. Will reuse Scope if not NULL. 685LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 686 LocalScope* Scope) { 687 if (!BuildOpts.AddImplicitDtors) 688 return Scope; 689 690 // Check if variable is local. 691 switch (VD->getStorageClass()) { 692 case SC_None: 693 case SC_Auto: 694 case SC_Register: 695 break; 696 default: return Scope; 697 } 698 699 // Check for const references bound to temporary. Set type to pointee. 700 QualType QT = VD->getType(); 701 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 702 QT = RT->getPointeeType(); 703 if (!QT.isConstQualified()) 704 return Scope; 705 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 706 return Scope; 707 } 708 709 // Check for constant size array. Set type to array element type. 710 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 711 if (AT->getSize() == 0) 712 return Scope; 713 QT = AT->getElementType(); 714 } 715 716 // Check if type is a C++ class with non-trivial destructor. 717 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 718 if (!CD->hasTrivialDestructor()) { 719 // Add the variable to scope 720 Scope = createOrReuseLocalScope(Scope); 721 Scope->addVar(VD); 722 ScopePos = Scope->begin(); 723 } 724 return Scope; 725} 726 727/// addLocalScopeAndDtors - For given statement add local scope for it and 728/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 729void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 730 if (!BuildOpts.AddImplicitDtors) 731 return; 732 733 LocalScope::const_iterator scopeBeginPos = ScopePos; 734 addLocalScopeForStmt(S); 735 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 736} 737 738/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 739/// automatic storage duration to CFGBlock's elements vector. Insertion will be 740/// performed in place specified with iterator. 741void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 742 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 743 BumpVectorContext& C = cfg->getBumpVectorContext(); 744 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 745 while (B != E) 746 I = Blk->insertAutomaticObjDtor(I, *B++, S); 747} 748 749/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 750/// automatic storage duration to CFGBlock's elements vector. Elements will be 751/// appended to physical end of the vector which happens to be logical 752/// beginning. 753void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 754 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 755 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 756} 757 758/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 759/// variables with automatic storage duration to CFGBlock's elements vector. 760/// Elements will be prepended to physical beginning of the vector which 761/// happens to be logical end. Use blocks terminator as statement that specifies 762/// destructors call site. 763void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 764 LocalScope::const_iterator B, LocalScope::const_iterator E) { 765 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 766} 767 768/// Visit - Walk the subtree of a statement and add extra 769/// blocks for ternary operators, &&, and ||. We also process "," and 770/// DeclStmts (which may contain nested control-flow). 771CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 772tryAgain: 773 if (!S) { 774 badCFG = true; 775 return 0; 776 } 777 switch (S->getStmtClass()) { 778 default: 779 return VisitStmt(S, asc); 780 781 case Stmt::AddrLabelExprClass: 782 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 783 784 case Stmt::BinaryOperatorClass: 785 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 786 787 case Stmt::BlockExprClass: 788 return VisitBlockExpr(cast<BlockExpr>(S), asc); 789 790 case Stmt::BreakStmtClass: 791 return VisitBreakStmt(cast<BreakStmt>(S)); 792 793 case Stmt::CallExprClass: 794 case Stmt::CXXOperatorCallExprClass: 795 return VisitCallExpr(cast<CallExpr>(S), asc); 796 797 case Stmt::CaseStmtClass: 798 return VisitCaseStmt(cast<CaseStmt>(S)); 799 800 case Stmt::ChooseExprClass: 801 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 802 803 case Stmt::CompoundStmtClass: 804 return VisitCompoundStmt(cast<CompoundStmt>(S)); 805 806 case Stmt::ConditionalOperatorClass: 807 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 808 809 case Stmt::ContinueStmtClass: 810 return VisitContinueStmt(cast<ContinueStmt>(S)); 811 812 case Stmt::CXXCatchStmtClass: 813 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 814 815 case Stmt::ExprWithCleanupsClass: 816 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 817 818 case Stmt::CXXBindTemporaryExprClass: 819 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 820 821 case Stmt::CXXConstructExprClass: 822 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 823 824 case Stmt::CXXFunctionalCastExprClass: 825 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 826 827 case Stmt::CXXTemporaryObjectExprClass: 828 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 829 830 case Stmt::CXXMemberCallExprClass: 831 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 832 833 case Stmt::CXXThrowExprClass: 834 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 835 836 case Stmt::CXXTryStmtClass: 837 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 838 839 case Stmt::DeclStmtClass: 840 return VisitDeclStmt(cast<DeclStmt>(S)); 841 842 case Stmt::DefaultStmtClass: 843 return VisitDefaultStmt(cast<DefaultStmt>(S)); 844 845 case Stmt::DoStmtClass: 846 return VisitDoStmt(cast<DoStmt>(S)); 847 848 case Stmt::ForStmtClass: 849 return VisitForStmt(cast<ForStmt>(S)); 850 851 case Stmt::GotoStmtClass: 852 return VisitGotoStmt(cast<GotoStmt>(S)); 853 854 case Stmt::IfStmtClass: 855 return VisitIfStmt(cast<IfStmt>(S)); 856 857 case Stmt::ImplicitCastExprClass: 858 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 859 860 case Stmt::IndirectGotoStmtClass: 861 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 862 863 case Stmt::LabelStmtClass: 864 return VisitLabelStmt(cast<LabelStmt>(S)); 865 866 case Stmt::MemberExprClass: 867 return VisitMemberExpr(cast<MemberExpr>(S), asc); 868 869 case Stmt::ObjCAtCatchStmtClass: 870 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 871 872 case Stmt::ObjCAtSynchronizedStmtClass: 873 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 874 875 case Stmt::ObjCAtThrowStmtClass: 876 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 877 878 case Stmt::ObjCAtTryStmtClass: 879 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 880 881 case Stmt::ObjCForCollectionStmtClass: 882 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 883 884 case Stmt::ParenExprClass: 885 S = cast<ParenExpr>(S)->getSubExpr(); 886 goto tryAgain; 887 888 case Stmt::NullStmtClass: 889 return Block; 890 891 case Stmt::ReturnStmtClass: 892 return VisitReturnStmt(cast<ReturnStmt>(S)); 893 894 case Stmt::SizeOfAlignOfExprClass: 895 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 896 897 case Stmt::StmtExprClass: 898 return VisitStmtExpr(cast<StmtExpr>(S), asc); 899 900 case Stmt::SwitchStmtClass: 901 return VisitSwitchStmt(cast<SwitchStmt>(S)); 902 903 case Stmt::UnaryOperatorClass: 904 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 905 906 case Stmt::WhileStmtClass: 907 return VisitWhileStmt(cast<WhileStmt>(S)); 908 } 909} 910 911CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 912 if (asc.alwaysAdd()) { 913 autoCreateBlock(); 914 appendStmt(Block, S, asc); 915 } 916 917 return VisitChildren(S); 918} 919 920/// VisitChildren - Visit the children of a Stmt. 921CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 922 CFGBlock *B = Block; 923 for (Stmt::child_iterator I = Terminator->child_begin(), 924 E = Terminator->child_end(); I != E; ++I) { 925 if (*I) B = Visit(*I); 926 } 927 return B; 928} 929 930CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 931 AddStmtChoice asc) { 932 AddressTakenLabels.insert(A->getLabel()); 933 934 if (asc.alwaysAdd()) { 935 autoCreateBlock(); 936 appendStmt(Block, A, asc); 937 } 938 939 return Block; 940} 941 942CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 943 AddStmtChoice asc) { 944 if (asc.alwaysAdd()) { 945 autoCreateBlock(); 946 appendStmt(Block, U, asc); 947 } 948 949 return Visit(U->getSubExpr(), AddStmtChoice()); 950} 951 952CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 953 AddStmtChoice asc) { 954 if (B->isLogicalOp()) { // && or || 955 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 956 appendStmt(ConfluenceBlock, B, asc); 957 958 if (badCFG) 959 return 0; 960 961 // create the block evaluating the LHS 962 CFGBlock* LHSBlock = createBlock(false); 963 LHSBlock->setTerminator(B); 964 965 // create the block evaluating the RHS 966 Succ = ConfluenceBlock; 967 Block = NULL; 968 CFGBlock* RHSBlock = addStmt(B->getRHS()); 969 970 if (RHSBlock) { 971 if (badCFG) 972 return 0; 973 } else { 974 // Create an empty block for cases where the RHS doesn't require 975 // any explicit statements in the CFG. 976 RHSBlock = createBlock(); 977 } 978 979 // See if this is a known constant. 980 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 981 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 982 KnownVal.negate(); 983 984 // Now link the LHSBlock with RHSBlock. 985 if (B->getOpcode() == BO_LOr) { 986 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 987 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 988 } else { 989 assert(B->getOpcode() == BO_LAnd); 990 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 991 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 992 } 993 994 // Generate the blocks for evaluating the LHS. 995 Block = LHSBlock; 996 return addStmt(B->getLHS()); 997 } 998 999 if (B->getOpcode() == BO_Comma) { // , 1000 autoCreateBlock(); 1001 appendStmt(Block, B, asc); 1002 addStmt(B->getRHS()); 1003 return addStmt(B->getLHS()); 1004 } 1005 1006 if (B->isAssignmentOp()) { 1007 if (asc.alwaysAdd()) { 1008 autoCreateBlock(); 1009 appendStmt(Block, B, asc); 1010 } 1011 Visit(B->getLHS()); 1012 return Visit(B->getRHS()); 1013 } 1014 1015 if (asc.alwaysAdd()) { 1016 autoCreateBlock(); 1017 appendStmt(Block, B, asc); 1018 } 1019 1020 CFGBlock *RBlock = Visit(B->getRHS()); 1021 CFGBlock *LBlock = Visit(B->getLHS()); 1022 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1023 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1024 // return RBlock. Otherwise we'll incorrectly return NULL. 1025 return (LBlock ? LBlock : RBlock); 1026} 1027 1028CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1029 if (asc.alwaysAdd()) { 1030 autoCreateBlock(); 1031 appendStmt(Block, E, asc); 1032 } 1033 return Block; 1034} 1035 1036CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1037 // "break" is a control-flow statement. Thus we stop processing the current 1038 // block. 1039 if (badCFG) 1040 return 0; 1041 1042 // Now create a new block that ends with the break statement. 1043 Block = createBlock(false); 1044 Block->setTerminator(B); 1045 1046 // If there is no target for the break, then we are looking at an incomplete 1047 // AST. This means that the CFG cannot be constructed. 1048 if (BreakJumpTarget.Block) { 1049 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 1050 AddSuccessor(Block, BreakJumpTarget.Block); 1051 } else 1052 badCFG = true; 1053 1054 1055 return Block; 1056} 1057 1058static bool CanThrow(Expr *E) { 1059 QualType Ty = E->getType(); 1060 if (Ty->isFunctionPointerType()) 1061 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1062 else if (Ty->isBlockPointerType()) 1063 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1064 1065 const FunctionType *FT = Ty->getAs<FunctionType>(); 1066 if (FT) { 1067 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1068 if (Proto->hasEmptyExceptionSpec()) 1069 return false; 1070 } 1071 return true; 1072} 1073 1074CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1075 // If this is a call to a no-return function, this stops the block here. 1076 bool NoReturn = false; 1077 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 1078 NoReturn = true; 1079 } 1080 1081 bool AddEHEdge = false; 1082 1083 // Languages without exceptions are assumed to not throw. 1084 if (Context->getLangOptions().Exceptions) { 1085 if (BuildOpts.AddEHEdges) 1086 AddEHEdge = true; 1087 } 1088 1089 if (FunctionDecl *FD = C->getDirectCallee()) { 1090 if (FD->hasAttr<NoReturnAttr>()) 1091 NoReturn = true; 1092 if (FD->hasAttr<NoThrowAttr>()) 1093 AddEHEdge = false; 1094 } 1095 1096 if (!CanThrow(C->getCallee())) 1097 AddEHEdge = false; 1098 1099 if (!NoReturn && !AddEHEdge) 1100 return VisitStmt(C, asc.withAlwaysAdd(true)); 1101 1102 if (Block) { 1103 Succ = Block; 1104 if (badCFG) 1105 return 0; 1106 } 1107 1108 Block = createBlock(!NoReturn); 1109 appendStmt(Block, C, asc); 1110 1111 if (NoReturn) { 1112 // Wire this to the exit block directly. 1113 AddSuccessor(Block, &cfg->getExit()); 1114 } 1115 if (AddEHEdge) { 1116 // Add exceptional edges. 1117 if (TryTerminatedBlock) 1118 AddSuccessor(Block, TryTerminatedBlock); 1119 else 1120 AddSuccessor(Block, &cfg->getExit()); 1121 } 1122 1123 return VisitChildren(C); 1124} 1125 1126CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1127 AddStmtChoice asc) { 1128 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1129 appendStmt(ConfluenceBlock, C, asc); 1130 if (badCFG) 1131 return 0; 1132 1133 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1134 Succ = ConfluenceBlock; 1135 Block = NULL; 1136 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1137 if (badCFG) 1138 return 0; 1139 1140 Succ = ConfluenceBlock; 1141 Block = NULL; 1142 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1143 if (badCFG) 1144 return 0; 1145 1146 Block = createBlock(false); 1147 // See if this is a known constant. 1148 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1149 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1150 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1151 Block->setTerminator(C); 1152 return addStmt(C->getCond()); 1153} 1154 1155 1156CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1157 addLocalScopeAndDtors(C); 1158 CFGBlock* LastBlock = Block; 1159 1160 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1161 I != E; ++I ) { 1162 // If we hit a segment of code just containing ';' (NullStmts), we can 1163 // get a null block back. In such cases, just use the LastBlock 1164 if (CFGBlock *newBlock = addStmt(*I)) 1165 LastBlock = newBlock; 1166 1167 if (badCFG) 1168 return NULL; 1169 } 1170 1171 return LastBlock; 1172} 1173 1174CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1175 AddStmtChoice asc) { 1176 // Create the confluence block that will "merge" the results of the ternary 1177 // expression. 1178 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1179 appendStmt(ConfluenceBlock, C, asc); 1180 if (badCFG) 1181 return 0; 1182 1183 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1184 1185 // Create a block for the LHS expression if there is an LHS expression. A 1186 // GCC extension allows LHS to be NULL, causing the condition to be the 1187 // value that is returned instead. 1188 // e.g: x ?: y is shorthand for: x ? x : y; 1189 Succ = ConfluenceBlock; 1190 Block = NULL; 1191 CFGBlock* LHSBlock = NULL; 1192 if (C->getLHS()) { 1193 LHSBlock = Visit(C->getLHS(), alwaysAdd); 1194 if (badCFG) 1195 return 0; 1196 Block = NULL; 1197 } 1198 1199 // Create the block for the RHS expression. 1200 Succ = ConfluenceBlock; 1201 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1202 if (badCFG) 1203 return 0; 1204 1205 // Create the block that will contain the condition. 1206 Block = createBlock(false); 1207 1208 // See if this is a known constant. 1209 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1210 if (LHSBlock) { 1211 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1212 } else { 1213 if (KnownVal.isFalse()) { 1214 // If we know the condition is false, add NULL as the successor for 1215 // the block containing the condition. In this case, the confluence 1216 // block will have just one predecessor. 1217 AddSuccessor(Block, 0); 1218 assert(ConfluenceBlock->pred_size() == 1); 1219 } else { 1220 // If we have no LHS expression, add the ConfluenceBlock as a direct 1221 // successor for the block containing the condition. Moreover, we need to 1222 // reverse the order of the predecessors in the ConfluenceBlock because 1223 // the RHSBlock will have been added to the succcessors already, and we 1224 // want the first predecessor to the the block containing the expression 1225 // for the case when the ternary expression evaluates to true. 1226 AddSuccessor(Block, ConfluenceBlock); 1227 // Note that there can possibly only be one predecessor if one of the 1228 // subexpressions resulted in calling a noreturn function. 1229 std::reverse(ConfluenceBlock->pred_begin(), 1230 ConfluenceBlock->pred_end()); 1231 } 1232 } 1233 1234 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1235 Block->setTerminator(C); 1236 return addStmt(C->getCond()); 1237} 1238 1239CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1240 if (DS->isSingleDecl()) 1241 return VisitDeclSubExpr(DS); 1242 1243 CFGBlock *B = 0; 1244 1245 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1246 typedef llvm::SmallVector<Decl*,10> BufTy; 1247 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1248 1249 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1250 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1251 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1252 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1253 1254 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1255 // automatically freed with the CFG. 1256 DeclGroupRef DG(*I); 1257 Decl *D = *I; 1258 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1259 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1260 1261 // Append the fake DeclStmt to block. 1262 B = VisitDeclSubExpr(DSNew); 1263 } 1264 1265 return B; 1266} 1267 1268/// VisitDeclSubExpr - Utility method to add block-level expressions for 1269/// DeclStmts and initializers in them. 1270CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1271 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1272 1273 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1274 1275 if (!VD) { 1276 autoCreateBlock(); 1277 appendStmt(Block, DS); 1278 return Block; 1279 } 1280 1281 bool IsReference = false; 1282 bool HasTemporaries = false; 1283 1284 // Destructors of temporaries in initialization expression should be called 1285 // after initialization finishes. 1286 Expr *Init = VD->getInit(); 1287 if (Init) { 1288 IsReference = VD->getType()->isReferenceType(); 1289 HasTemporaries = isa<ExprWithCleanups>(Init); 1290 1291 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1292 // Generate destructors for temporaries in initialization expression. 1293 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1294 IsReference); 1295 } 1296 } 1297 1298 autoCreateBlock(); 1299 appendStmt(Block, DS); 1300 1301 if (Init) { 1302 if (HasTemporaries) 1303 // For expression with temporaries go directly to subexpression to omit 1304 // generating destructors for the second time. 1305 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1306 else 1307 Visit(Init); 1308 } 1309 1310 // If the type of VD is a VLA, then we must process its size expressions. 1311 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1312 VA = FindVA(VA->getElementType().getTypePtr())) 1313 Block = addStmt(VA->getSizeExpr()); 1314 1315 // Remove variable from local scope. 1316 if (ScopePos && VD == *ScopePos) 1317 ++ScopePos; 1318 1319 return Block; 1320} 1321 1322CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1323 // We may see an if statement in the middle of a basic block, or it may be the 1324 // first statement we are processing. In either case, we create a new basic 1325 // block. First, we create the blocks for the then...else statements, and 1326 // then we create the block containing the if statement. If we were in the 1327 // middle of a block, we stop processing that block. That block is then the 1328 // implicit successor for the "then" and "else" clauses. 1329 1330 // Save local scope position because in case of condition variable ScopePos 1331 // won't be restored when traversing AST. 1332 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1333 1334 // Create local scope for possible condition variable. 1335 // Store scope position. Add implicit destructor. 1336 if (VarDecl* VD = I->getConditionVariable()) { 1337 LocalScope::const_iterator BeginScopePos = ScopePos; 1338 addLocalScopeForVarDecl(VD); 1339 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1340 } 1341 1342 // The block we were proccessing is now finished. Make it the successor 1343 // block. 1344 if (Block) { 1345 Succ = Block; 1346 if (badCFG) 1347 return 0; 1348 } 1349 1350 // Process the false branch. 1351 CFGBlock* ElseBlock = Succ; 1352 1353 if (Stmt* Else = I->getElse()) { 1354 SaveAndRestore<CFGBlock*> sv(Succ); 1355 1356 // NULL out Block so that the recursive call to Visit will 1357 // create a new basic block. 1358 Block = NULL; 1359 1360 // If branch is not a compound statement create implicit scope 1361 // and add destructors. 1362 if (!isa<CompoundStmt>(Else)) 1363 addLocalScopeAndDtors(Else); 1364 1365 ElseBlock = addStmt(Else); 1366 1367 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1368 ElseBlock = sv.get(); 1369 else if (Block) { 1370 if (badCFG) 1371 return 0; 1372 } 1373 } 1374 1375 // Process the true branch. 1376 CFGBlock* ThenBlock; 1377 { 1378 Stmt* Then = I->getThen(); 1379 assert(Then); 1380 SaveAndRestore<CFGBlock*> sv(Succ); 1381 Block = NULL; 1382 1383 // If branch is not a compound statement create implicit scope 1384 // and add destructors. 1385 if (!isa<CompoundStmt>(Then)) 1386 addLocalScopeAndDtors(Then); 1387 1388 ThenBlock = addStmt(Then); 1389 1390 if (!ThenBlock) { 1391 // We can reach here if the "then" body has all NullStmts. 1392 // Create an empty block so we can distinguish between true and false 1393 // branches in path-sensitive analyses. 1394 ThenBlock = createBlock(false); 1395 AddSuccessor(ThenBlock, sv.get()); 1396 } else if (Block) { 1397 if (badCFG) 1398 return 0; 1399 } 1400 } 1401 1402 // Now create a new block containing the if statement. 1403 Block = createBlock(false); 1404 1405 // Set the terminator of the new block to the If statement. 1406 Block->setTerminator(I); 1407 1408 // See if this is a known constant. 1409 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1410 1411 // Now add the successors. 1412 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1413 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1414 1415 // Add the condition as the last statement in the new block. This may create 1416 // new blocks as the condition may contain control-flow. Any newly created 1417 // blocks will be pointed to be "Block". 1418 Block = addStmt(I->getCond()); 1419 1420 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1421 // and the condition variable initialization to the CFG. 1422 if (VarDecl *VD = I->getConditionVariable()) { 1423 if (Expr *Init = VD->getInit()) { 1424 autoCreateBlock(); 1425 appendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1426 addStmt(Init); 1427 } 1428 } 1429 1430 return Block; 1431} 1432 1433 1434CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1435 // If we were in the middle of a block we stop processing that block. 1436 // 1437 // NOTE: If a "return" appears in the middle of a block, this means that the 1438 // code afterwards is DEAD (unreachable). We still keep a basic block 1439 // for that code; a simple "mark-and-sweep" from the entry block will be 1440 // able to report such dead blocks. 1441 1442 // Create the new block. 1443 Block = createBlock(false); 1444 1445 // The Exit block is the only successor. 1446 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1447 AddSuccessor(Block, &cfg->getExit()); 1448 1449 // Add the return statement to the block. This may create new blocks if R 1450 // contains control-flow (short-circuit operations). 1451 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1452} 1453 1454CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1455 // Get the block of the labeled statement. Add it to our map. 1456 addStmt(L->getSubStmt()); 1457 CFGBlock* LabelBlock = Block; 1458 1459 if (!LabelBlock) // This can happen when the body is empty, i.e. 1460 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1461 1462 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1463 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1464 1465 // Labels partition blocks, so this is the end of the basic block we were 1466 // processing (L is the block's label). Because this is label (and we have 1467 // already processed the substatement) there is no extra control-flow to worry 1468 // about. 1469 LabelBlock->setLabel(L); 1470 if (badCFG) 1471 return 0; 1472 1473 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1474 Block = NULL; 1475 1476 // This block is now the implicit successor of other blocks. 1477 Succ = LabelBlock; 1478 1479 return LabelBlock; 1480} 1481 1482CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1483 // Goto is a control-flow statement. Thus we stop processing the current 1484 // block and create a new one. 1485 1486 Block = createBlock(false); 1487 Block->setTerminator(G); 1488 1489 // If we already know the mapping to the label block add the successor now. 1490 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1491 1492 if (I == LabelMap.end()) 1493 // We will need to backpatch this block later. 1494 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1495 else { 1496 JumpTarget JT = I->second; 1497 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1498 AddSuccessor(Block, JT.Block); 1499 } 1500 1501 return Block; 1502} 1503 1504CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1505 CFGBlock* LoopSuccessor = NULL; 1506 1507 // Save local scope position because in case of condition variable ScopePos 1508 // won't be restored when traversing AST. 1509 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1510 1511 // Create local scope for init statement and possible condition variable. 1512 // Add destructor for init statement and condition variable. 1513 // Store scope position for continue statement. 1514 if (Stmt* Init = F->getInit()) 1515 addLocalScopeForStmt(Init); 1516 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1517 1518 if (VarDecl* VD = F->getConditionVariable()) 1519 addLocalScopeForVarDecl(VD); 1520 LocalScope::const_iterator ContinueScopePos = ScopePos; 1521 1522 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1523 1524 // "for" is a control-flow statement. Thus we stop processing the current 1525 // block. 1526 if (Block) { 1527 if (badCFG) 1528 return 0; 1529 LoopSuccessor = Block; 1530 } else 1531 LoopSuccessor = Succ; 1532 1533 // Save the current value for the break targets. 1534 // All breaks should go to the code following the loop. 1535 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1536 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1537 1538 // Because of short-circuit evaluation, the condition of the loop can span 1539 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1540 // evaluate the condition. 1541 CFGBlock* ExitConditionBlock = createBlock(false); 1542 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1543 1544 // Set the terminator for the "exit" condition block. 1545 ExitConditionBlock->setTerminator(F); 1546 1547 // Now add the actual condition to the condition block. Because the condition 1548 // itself may contain control-flow, new blocks may be created. 1549 if (Stmt* C = F->getCond()) { 1550 Block = ExitConditionBlock; 1551 EntryConditionBlock = addStmt(C); 1552 assert(Block == EntryConditionBlock || 1553 (Block == 0 && EntryConditionBlock == Succ)); 1554 1555 // If this block contains a condition variable, add both the condition 1556 // variable and initializer to the CFG. 1557 if (VarDecl *VD = F->getConditionVariable()) { 1558 if (Expr *Init = VD->getInit()) { 1559 autoCreateBlock(); 1560 appendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1561 EntryConditionBlock = addStmt(Init); 1562 assert(Block == EntryConditionBlock); 1563 } 1564 } 1565 1566 if (Block) { 1567 if (badCFG) 1568 return 0; 1569 } 1570 } 1571 1572 // The condition block is the implicit successor for the loop body as well as 1573 // any code above the loop. 1574 Succ = EntryConditionBlock; 1575 1576 // See if this is a known constant. 1577 TryResult KnownVal(true); 1578 1579 if (F->getCond()) 1580 KnownVal = TryEvaluateBool(F->getCond()); 1581 1582 // Now create the loop body. 1583 { 1584 assert(F->getBody()); 1585 1586 // Save the current values for Block, Succ, and continue targets. 1587 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1588 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1589 1590 // Create a new block to contain the (bottom) of the loop body. 1591 Block = NULL; 1592 1593 // Loop body should end with destructor of Condition variable (if any). 1594 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1595 1596 if (Stmt* I = F->getInc()) { 1597 // Generate increment code in its own basic block. This is the target of 1598 // continue statements. 1599 Succ = addStmt(I); 1600 } else { 1601 // No increment code. Create a special, empty, block that is used as the 1602 // target block for "looping back" to the start of the loop. 1603 assert(Succ == EntryConditionBlock); 1604 Succ = Block ? Block : createBlock(); 1605 } 1606 1607 // Finish up the increment (or empty) block if it hasn't been already. 1608 if (Block) { 1609 assert(Block == Succ); 1610 if (badCFG) 1611 return 0; 1612 Block = 0; 1613 } 1614 1615 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1616 1617 // The starting block for the loop increment is the block that should 1618 // represent the 'loop target' for looping back to the start of the loop. 1619 ContinueJumpTarget.Block->setLoopTarget(F); 1620 1621 // If body is not a compound statement create implicit scope 1622 // and add destructors. 1623 if (!isa<CompoundStmt>(F->getBody())) 1624 addLocalScopeAndDtors(F->getBody()); 1625 1626 // Now populate the body block, and in the process create new blocks as we 1627 // walk the body of the loop. 1628 CFGBlock* BodyBlock = addStmt(F->getBody()); 1629 1630 if (!BodyBlock) 1631 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1632 else if (badCFG) 1633 return 0; 1634 1635 // This new body block is a successor to our "exit" condition block. 1636 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1637 } 1638 1639 // Link up the condition block with the code that follows the loop. (the 1640 // false branch). 1641 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1642 1643 // If the loop contains initialization, create a new block for those 1644 // statements. This block can also contain statements that precede the loop. 1645 if (Stmt* I = F->getInit()) { 1646 Block = createBlock(); 1647 return addStmt(I); 1648 } 1649 1650 // There is no loop initialization. We are thus basically a while loop. 1651 // NULL out Block to force lazy block construction. 1652 Block = NULL; 1653 Succ = EntryConditionBlock; 1654 return EntryConditionBlock; 1655} 1656 1657CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1658 if (asc.alwaysAdd()) { 1659 autoCreateBlock(); 1660 appendStmt(Block, M, asc); 1661 } 1662 return Visit(M->getBase()); 1663} 1664 1665CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1666 // Objective-C fast enumeration 'for' statements: 1667 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1668 // 1669 // for ( Type newVariable in collection_expression ) { statements } 1670 // 1671 // becomes: 1672 // 1673 // prologue: 1674 // 1. collection_expression 1675 // T. jump to loop_entry 1676 // loop_entry: 1677 // 1. side-effects of element expression 1678 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1679 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1680 // TB: 1681 // statements 1682 // T. jump to loop_entry 1683 // FB: 1684 // what comes after 1685 // 1686 // and 1687 // 1688 // Type existingItem; 1689 // for ( existingItem in expression ) { statements } 1690 // 1691 // becomes: 1692 // 1693 // the same with newVariable replaced with existingItem; the binding works 1694 // the same except that for one ObjCForCollectionStmt::getElement() returns 1695 // a DeclStmt and the other returns a DeclRefExpr. 1696 // 1697 1698 CFGBlock* LoopSuccessor = 0; 1699 1700 if (Block) { 1701 if (badCFG) 1702 return 0; 1703 LoopSuccessor = Block; 1704 Block = 0; 1705 } else 1706 LoopSuccessor = Succ; 1707 1708 // Build the condition blocks. 1709 CFGBlock* ExitConditionBlock = createBlock(false); 1710 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1711 1712 // Set the terminator for the "exit" condition block. 1713 ExitConditionBlock->setTerminator(S); 1714 1715 // The last statement in the block should be the ObjCForCollectionStmt, which 1716 // performs the actual binding to 'element' and determines if there are any 1717 // more items in the collection. 1718 appendStmt(ExitConditionBlock, S); 1719 Block = ExitConditionBlock; 1720 1721 // Walk the 'element' expression to see if there are any side-effects. We 1722 // generate new blocks as necesary. We DON'T add the statement by default to 1723 // the CFG unless it contains control-flow. 1724 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1725 if (Block) { 1726 if (badCFG) 1727 return 0; 1728 Block = 0; 1729 } 1730 1731 // The condition block is the implicit successor for the loop body as well as 1732 // any code above the loop. 1733 Succ = EntryConditionBlock; 1734 1735 // Now create the true branch. 1736 { 1737 // Save the current values for Succ, continue and break targets. 1738 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1739 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1740 save_break(BreakJumpTarget); 1741 1742 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1743 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1744 1745 CFGBlock* BodyBlock = addStmt(S->getBody()); 1746 1747 if (!BodyBlock) 1748 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1749 else if (Block) { 1750 if (badCFG) 1751 return 0; 1752 } 1753 1754 // This new body block is a successor to our "exit" condition block. 1755 AddSuccessor(ExitConditionBlock, BodyBlock); 1756 } 1757 1758 // Link up the condition block with the code that follows the loop. 1759 // (the false branch). 1760 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1761 1762 // Now create a prologue block to contain the collection expression. 1763 Block = createBlock(); 1764 return addStmt(S->getCollection()); 1765} 1766 1767CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1768 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1769 1770 // Inline the body. 1771 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1772 1773 // The sync body starts its own basic block. This makes it a little easier 1774 // for diagnostic clients. 1775 if (SyncBlock) { 1776 if (badCFG) 1777 return 0; 1778 1779 Block = 0; 1780 Succ = SyncBlock; 1781 } 1782 1783 // Add the @synchronized to the CFG. 1784 autoCreateBlock(); 1785 appendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1786 1787 // Inline the sync expression. 1788 return addStmt(S->getSynchExpr()); 1789} 1790 1791CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1792 // FIXME 1793 return NYS(); 1794} 1795 1796CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1797 CFGBlock* LoopSuccessor = NULL; 1798 1799 // Save local scope position because in case of condition variable ScopePos 1800 // won't be restored when traversing AST. 1801 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1802 1803 // Create local scope for possible condition variable. 1804 // Store scope position for continue statement. 1805 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1806 if (VarDecl* VD = W->getConditionVariable()) { 1807 addLocalScopeForVarDecl(VD); 1808 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1809 } 1810 1811 // "while" is a control-flow statement. Thus we stop processing the current 1812 // block. 1813 if (Block) { 1814 if (badCFG) 1815 return 0; 1816 LoopSuccessor = Block; 1817 } else 1818 LoopSuccessor = Succ; 1819 1820 // Because of short-circuit evaluation, the condition of the loop can span 1821 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1822 // evaluate the condition. 1823 CFGBlock* ExitConditionBlock = createBlock(false); 1824 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1825 1826 // Set the terminator for the "exit" condition block. 1827 ExitConditionBlock->setTerminator(W); 1828 1829 // Now add the actual condition to the condition block. Because the condition 1830 // itself may contain control-flow, new blocks may be created. Thus we update 1831 // "Succ" after adding the condition. 1832 if (Stmt* C = W->getCond()) { 1833 Block = ExitConditionBlock; 1834 EntryConditionBlock = addStmt(C); 1835 // The condition might finish the current 'Block'. 1836 Block = EntryConditionBlock; 1837 1838 // If this block contains a condition variable, add both the condition 1839 // variable and initializer to the CFG. 1840 if (VarDecl *VD = W->getConditionVariable()) { 1841 if (Expr *Init = VD->getInit()) { 1842 autoCreateBlock(); 1843 appendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1844 EntryConditionBlock = addStmt(Init); 1845 assert(Block == EntryConditionBlock); 1846 } 1847 } 1848 1849 if (Block) { 1850 if (badCFG) 1851 return 0; 1852 } 1853 } 1854 1855 // The condition block is the implicit successor for the loop body as well as 1856 // any code above the loop. 1857 Succ = EntryConditionBlock; 1858 1859 // See if this is a known constant. 1860 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1861 1862 // Process the loop body. 1863 { 1864 assert(W->getBody()); 1865 1866 // Save the current values for Block, Succ, and continue and break targets 1867 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1868 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1869 save_break(BreakJumpTarget); 1870 1871 // Create an empty block to represent the transition block for looping back 1872 // to the head of the loop. 1873 Block = 0; 1874 assert(Succ == EntryConditionBlock); 1875 Succ = createBlock(); 1876 Succ->setLoopTarget(W); 1877 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1878 1879 // All breaks should go to the code following the loop. 1880 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1881 1882 // NULL out Block to force lazy instantiation of blocks for the body. 1883 Block = NULL; 1884 1885 // Loop body should end with destructor of Condition variable (if any). 1886 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1887 1888 // If body is not a compound statement create implicit scope 1889 // and add destructors. 1890 if (!isa<CompoundStmt>(W->getBody())) 1891 addLocalScopeAndDtors(W->getBody()); 1892 1893 // Create the body. The returned block is the entry to the loop body. 1894 CFGBlock* BodyBlock = addStmt(W->getBody()); 1895 1896 if (!BodyBlock) 1897 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1898 else if (Block) { 1899 if (badCFG) 1900 return 0; 1901 } 1902 1903 // Add the loop body entry as a successor to the condition. 1904 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1905 } 1906 1907 // Link up the condition block with the code that follows the loop. (the 1908 // false branch). 1909 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1910 1911 // There can be no more statements in the condition block since we loop back 1912 // to this block. NULL out Block to force lazy creation of another block. 1913 Block = NULL; 1914 1915 // Return the condition block, which is the dominating block for the loop. 1916 Succ = EntryConditionBlock; 1917 return EntryConditionBlock; 1918} 1919 1920 1921CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1922 // FIXME: For now we pretend that @catch and the code it contains does not 1923 // exit. 1924 return Block; 1925} 1926 1927CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1928 // FIXME: This isn't complete. We basically treat @throw like a return 1929 // statement. 1930 1931 // If we were in the middle of a block we stop processing that block. 1932 if (badCFG) 1933 return 0; 1934 1935 // Create the new block. 1936 Block = createBlock(false); 1937 1938 // The Exit block is the only successor. 1939 AddSuccessor(Block, &cfg->getExit()); 1940 1941 // Add the statement to the block. This may create new blocks if S contains 1942 // control-flow (short-circuit operations). 1943 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1944} 1945 1946CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1947 // If we were in the middle of a block we stop processing that block. 1948 if (badCFG) 1949 return 0; 1950 1951 // Create the new block. 1952 Block = createBlock(false); 1953 1954 if (TryTerminatedBlock) 1955 // The current try statement is the only successor. 1956 AddSuccessor(Block, TryTerminatedBlock); 1957 else 1958 // otherwise the Exit block is the only successor. 1959 AddSuccessor(Block, &cfg->getExit()); 1960 1961 // Add the statement to the block. This may create new blocks if S contains 1962 // control-flow (short-circuit operations). 1963 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1964} 1965 1966CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1967 CFGBlock* LoopSuccessor = NULL; 1968 1969 // "do...while" is a control-flow statement. Thus we stop processing the 1970 // current block. 1971 if (Block) { 1972 if (badCFG) 1973 return 0; 1974 LoopSuccessor = Block; 1975 } else 1976 LoopSuccessor = Succ; 1977 1978 // Because of short-circuit evaluation, the condition of the loop can span 1979 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1980 // evaluate the condition. 1981 CFGBlock* ExitConditionBlock = createBlock(false); 1982 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1983 1984 // Set the terminator for the "exit" condition block. 1985 ExitConditionBlock->setTerminator(D); 1986 1987 // Now add the actual condition to the condition block. Because the condition 1988 // itself may contain control-flow, new blocks may be created. 1989 if (Stmt* C = D->getCond()) { 1990 Block = ExitConditionBlock; 1991 EntryConditionBlock = addStmt(C); 1992 if (Block) { 1993 if (badCFG) 1994 return 0; 1995 } 1996 } 1997 1998 // The condition block is the implicit successor for the loop body. 1999 Succ = EntryConditionBlock; 2000 2001 // See if this is a known constant. 2002 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 2003 2004 // Process the loop body. 2005 CFGBlock* BodyBlock = NULL; 2006 { 2007 assert(D->getBody()); 2008 2009 // Save the current values for Block, Succ, and continue and break targets 2010 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2011 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2012 save_break(BreakJumpTarget); 2013 2014 // All continues within this loop should go to the condition block 2015 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2016 2017 // All breaks should go to the code following the loop. 2018 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2019 2020 // NULL out Block to force lazy instantiation of blocks for the body. 2021 Block = NULL; 2022 2023 // If body is not a compound statement create implicit scope 2024 // and add destructors. 2025 if (!isa<CompoundStmt>(D->getBody())) 2026 addLocalScopeAndDtors(D->getBody()); 2027 2028 // Create the body. The returned block is the entry to the loop body. 2029 BodyBlock = addStmt(D->getBody()); 2030 2031 if (!BodyBlock) 2032 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2033 else if (Block) { 2034 if (badCFG) 2035 return 0; 2036 } 2037 2038 if (!KnownVal.isFalse()) { 2039 // Add an intermediate block between the BodyBlock and the 2040 // ExitConditionBlock to represent the "loop back" transition. Create an 2041 // empty block to represent the transition block for looping back to the 2042 // head of the loop. 2043 // FIXME: Can we do this more efficiently without adding another block? 2044 Block = NULL; 2045 Succ = BodyBlock; 2046 CFGBlock *LoopBackBlock = createBlock(); 2047 LoopBackBlock->setLoopTarget(D); 2048 2049 // Add the loop body entry as a successor to the condition. 2050 AddSuccessor(ExitConditionBlock, LoopBackBlock); 2051 } 2052 else 2053 AddSuccessor(ExitConditionBlock, NULL); 2054 } 2055 2056 // Link up the condition block with the code that follows the loop. 2057 // (the false branch). 2058 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2059 2060 // There can be no more statements in the body block(s) since we loop back to 2061 // the body. NULL out Block to force lazy creation of another block. 2062 Block = NULL; 2063 2064 // Return the loop body, which is the dominating block for the loop. 2065 Succ = BodyBlock; 2066 return BodyBlock; 2067} 2068 2069CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2070 // "continue" is a control-flow statement. Thus we stop processing the 2071 // current block. 2072 if (badCFG) 2073 return 0; 2074 2075 // Now create a new block that ends with the continue statement. 2076 Block = createBlock(false); 2077 Block->setTerminator(C); 2078 2079 // If there is no target for the continue, then we are looking at an 2080 // incomplete AST. This means the CFG cannot be constructed. 2081 if (ContinueJumpTarget.Block) { 2082 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 2083 AddSuccessor(Block, ContinueJumpTarget.Block); 2084 } else 2085 badCFG = true; 2086 2087 return Block; 2088} 2089 2090CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 2091 AddStmtChoice asc) { 2092 2093 if (asc.alwaysAdd()) { 2094 autoCreateBlock(); 2095 appendStmt(Block, E); 2096 } 2097 2098 // VLA types have expressions that must be evaluated. 2099 if (E->isArgumentType()) { 2100 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 2101 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2102 addStmt(VA->getSizeExpr()); 2103 } 2104 2105 return Block; 2106} 2107 2108/// VisitStmtExpr - Utility method to handle (nested) statement 2109/// expressions (a GCC extension). 2110CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2111 if (asc.alwaysAdd()) { 2112 autoCreateBlock(); 2113 appendStmt(Block, SE); 2114 } 2115 return VisitCompoundStmt(SE->getSubStmt()); 2116} 2117 2118CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2119 // "switch" is a control-flow statement. Thus we stop processing the current 2120 // block. 2121 CFGBlock* SwitchSuccessor = NULL; 2122 2123 // Save local scope position because in case of condition variable ScopePos 2124 // won't be restored when traversing AST. 2125 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2126 2127 // Create local scope for possible condition variable. 2128 // Store scope position. Add implicit destructor. 2129 if (VarDecl* VD = Terminator->getConditionVariable()) { 2130 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2131 addLocalScopeForVarDecl(VD); 2132 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2133 } 2134 2135 if (Block) { 2136 if (badCFG) 2137 return 0; 2138 SwitchSuccessor = Block; 2139 } else SwitchSuccessor = Succ; 2140 2141 // Save the current "switch" context. 2142 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2143 save_default(DefaultCaseBlock); 2144 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2145 2146 // Set the "default" case to be the block after the switch statement. If the 2147 // switch statement contains a "default:", this value will be overwritten with 2148 // the block for that code. 2149 DefaultCaseBlock = SwitchSuccessor; 2150 2151 // Create a new block that will contain the switch statement. 2152 SwitchTerminatedBlock = createBlock(false); 2153 2154 // Now process the switch body. The code after the switch is the implicit 2155 // successor. 2156 Succ = SwitchSuccessor; 2157 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2158 2159 // When visiting the body, the case statements should automatically get linked 2160 // up to the switch. We also don't keep a pointer to the body, since all 2161 // control-flow from the switch goes to case/default statements. 2162 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2163 Block = NULL; 2164 2165 // If body is not a compound statement create implicit scope 2166 // and add destructors. 2167 if (!isa<CompoundStmt>(Terminator->getBody())) 2168 addLocalScopeAndDtors(Terminator->getBody()); 2169 2170 addStmt(Terminator->getBody()); 2171 if (Block) { 2172 if (badCFG) 2173 return 0; 2174 } 2175 2176 // If we have no "default:" case, the default transition is to the code 2177 // following the switch body. 2178 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2179 2180 // Add the terminator and condition in the switch block. 2181 SwitchTerminatedBlock->setTerminator(Terminator); 2182 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2183 Block = SwitchTerminatedBlock; 2184 Block = addStmt(Terminator->getCond()); 2185 2186 // Finally, if the SwitchStmt contains a condition variable, add both the 2187 // SwitchStmt and the condition variable initialization to the CFG. 2188 if (VarDecl *VD = Terminator->getConditionVariable()) { 2189 if (Expr *Init = VD->getInit()) { 2190 autoCreateBlock(); 2191 appendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2192 addStmt(Init); 2193 } 2194 } 2195 2196 return Block; 2197} 2198 2199CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2200 // CaseStmts are essentially labels, so they are the first statement in a 2201 // block. 2202 CFGBlock *TopBlock = 0, *LastBlock = 0; 2203 2204 if (Stmt *Sub = CS->getSubStmt()) { 2205 // For deeply nested chains of CaseStmts, instead of doing a recursion 2206 // (which can blow out the stack), manually unroll and create blocks 2207 // along the way. 2208 while (isa<CaseStmt>(Sub)) { 2209 CFGBlock *CurrentBlock = createBlock(false); 2210 CurrentBlock->setLabel(CS); 2211 2212 if (TopBlock) 2213 AddSuccessor(LastBlock, CurrentBlock); 2214 else 2215 TopBlock = CurrentBlock; 2216 2217 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2218 LastBlock = CurrentBlock; 2219 2220 CS = cast<CaseStmt>(Sub); 2221 Sub = CS->getSubStmt(); 2222 } 2223 2224 addStmt(Sub); 2225 } 2226 2227 CFGBlock* CaseBlock = Block; 2228 if (!CaseBlock) 2229 CaseBlock = createBlock(); 2230 2231 // Cases statements partition blocks, so this is the top of the basic block we 2232 // were processing (the "case XXX:" is the label). 2233 CaseBlock->setLabel(CS); 2234 2235 if (badCFG) 2236 return 0; 2237 2238 // Add this block to the list of successors for the block with the switch 2239 // statement. 2240 assert(SwitchTerminatedBlock); 2241 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2242 2243 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2244 Block = NULL; 2245 2246 if (TopBlock) { 2247 AddSuccessor(LastBlock, CaseBlock); 2248 Succ = TopBlock; 2249 } else { 2250 // This block is now the implicit successor of other blocks. 2251 Succ = CaseBlock; 2252 } 2253 2254 return Succ; 2255} 2256 2257CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2258 if (Terminator->getSubStmt()) 2259 addStmt(Terminator->getSubStmt()); 2260 2261 DefaultCaseBlock = Block; 2262 2263 if (!DefaultCaseBlock) 2264 DefaultCaseBlock = createBlock(); 2265 2266 // Default statements partition blocks, so this is the top of the basic block 2267 // we were processing (the "default:" is the label). 2268 DefaultCaseBlock->setLabel(Terminator); 2269 2270 if (badCFG) 2271 return 0; 2272 2273 // Unlike case statements, we don't add the default block to the successors 2274 // for the switch statement immediately. This is done when we finish 2275 // processing the switch statement. This allows for the default case 2276 // (including a fall-through to the code after the switch statement) to always 2277 // be the last successor of a switch-terminated block. 2278 2279 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2280 Block = NULL; 2281 2282 // This block is now the implicit successor of other blocks. 2283 Succ = DefaultCaseBlock; 2284 2285 return DefaultCaseBlock; 2286} 2287 2288CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2289 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2290 // current block. 2291 CFGBlock* TrySuccessor = NULL; 2292 2293 if (Block) { 2294 if (badCFG) 2295 return 0; 2296 TrySuccessor = Block; 2297 } else TrySuccessor = Succ; 2298 2299 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2300 2301 // Create a new block that will contain the try statement. 2302 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2303 // Add the terminator in the try block. 2304 NewTryTerminatedBlock->setTerminator(Terminator); 2305 2306 bool HasCatchAll = false; 2307 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2308 // The code after the try is the implicit successor. 2309 Succ = TrySuccessor; 2310 CXXCatchStmt *CS = Terminator->getHandler(h); 2311 if (CS->getExceptionDecl() == 0) { 2312 HasCatchAll = true; 2313 } 2314 Block = NULL; 2315 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2316 if (CatchBlock == 0) 2317 return 0; 2318 // Add this block to the list of successors for the block with the try 2319 // statement. 2320 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2321 } 2322 if (!HasCatchAll) { 2323 if (PrevTryTerminatedBlock) 2324 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2325 else 2326 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2327 } 2328 2329 // The code after the try is the implicit successor. 2330 Succ = TrySuccessor; 2331 2332 // Save the current "try" context. 2333 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2334 TryTerminatedBlock = NewTryTerminatedBlock; 2335 2336 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2337 Block = NULL; 2338 Block = addStmt(Terminator->getTryBlock()); 2339 return Block; 2340} 2341 2342CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2343 // CXXCatchStmt are treated like labels, so they are the first statement in a 2344 // block. 2345 2346 // Save local scope position because in case of exception variable ScopePos 2347 // won't be restored when traversing AST. 2348 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2349 2350 // Create local scope for possible exception variable. 2351 // Store scope position. Add implicit destructor. 2352 if (VarDecl* VD = CS->getExceptionDecl()) { 2353 LocalScope::const_iterator BeginScopePos = ScopePos; 2354 addLocalScopeForVarDecl(VD); 2355 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2356 } 2357 2358 if (CS->getHandlerBlock()) 2359 addStmt(CS->getHandlerBlock()); 2360 2361 CFGBlock* CatchBlock = Block; 2362 if (!CatchBlock) 2363 CatchBlock = createBlock(); 2364 2365 CatchBlock->setLabel(CS); 2366 2367 if (badCFG) 2368 return 0; 2369 2370 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2371 Block = NULL; 2372 2373 return CatchBlock; 2374} 2375 2376CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2377 AddStmtChoice asc) { 2378 if (BuildOpts.AddImplicitDtors) { 2379 // If adding implicit destructors visit the full expression for adding 2380 // destructors of temporaries. 2381 VisitForTemporaryDtors(E->getSubExpr()); 2382 2383 // Full expression has to be added as CFGStmt so it will be sequenced 2384 // before destructors of it's temporaries. 2385 asc = asc.withAlwaysAdd(true); 2386 } 2387 return Visit(E->getSubExpr(), asc); 2388} 2389 2390CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2391 AddStmtChoice asc) { 2392 if (asc.alwaysAdd()) { 2393 autoCreateBlock(); 2394 appendStmt(Block, E, asc); 2395 2396 // We do not want to propagate the AlwaysAdd property. 2397 asc = asc.withAlwaysAdd(false); 2398 } 2399 return Visit(E->getSubExpr(), asc); 2400} 2401 2402CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2403 AddStmtChoice asc) { 2404 autoCreateBlock(); 2405 if (!C->isElidable()) 2406 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2407 2408 return VisitChildren(C); 2409} 2410 2411CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2412 AddStmtChoice asc) { 2413 if (asc.alwaysAdd()) { 2414 autoCreateBlock(); 2415 appendStmt(Block, E, asc); 2416 // We do not want to propagate the AlwaysAdd property. 2417 asc = asc.withAlwaysAdd(false); 2418 } 2419 return Visit(E->getSubExpr(), asc); 2420} 2421 2422CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2423 AddStmtChoice asc) { 2424 autoCreateBlock(); 2425 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2426 return VisitChildren(C); 2427} 2428 2429CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2430 AddStmtChoice asc) { 2431 autoCreateBlock(); 2432 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2433 return VisitChildren(C); 2434} 2435 2436CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2437 AddStmtChoice asc) { 2438 if (asc.alwaysAdd()) { 2439 autoCreateBlock(); 2440 appendStmt(Block, E, asc); 2441 } 2442 return Visit(E->getSubExpr(), AddStmtChoice()); 2443} 2444 2445CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2446 // Lazily create the indirect-goto dispatch block if there isn't one already. 2447 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2448 2449 if (!IBlock) { 2450 IBlock = createBlock(false); 2451 cfg->setIndirectGotoBlock(IBlock); 2452 } 2453 2454 // IndirectGoto is a control-flow statement. Thus we stop processing the 2455 // current block and create a new one. 2456 if (badCFG) 2457 return 0; 2458 2459 Block = createBlock(false); 2460 Block->setTerminator(I); 2461 AddSuccessor(Block, IBlock); 2462 return addStmt(I->getTarget()); 2463} 2464 2465CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2466tryAgain: 2467 if (!E) { 2468 badCFG = true; 2469 return NULL; 2470 } 2471 switch (E->getStmtClass()) { 2472 default: 2473 return VisitChildrenForTemporaryDtors(E); 2474 2475 case Stmt::BinaryOperatorClass: 2476 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2477 2478 case Stmt::CXXBindTemporaryExprClass: 2479 return VisitCXXBindTemporaryExprForTemporaryDtors( 2480 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2481 2482 case Stmt::ConditionalOperatorClass: 2483 return VisitConditionalOperatorForTemporaryDtors( 2484 cast<ConditionalOperator>(E), BindToTemporary); 2485 2486 case Stmt::ImplicitCastExprClass: 2487 // For implicit cast we want BindToTemporary to be passed further. 2488 E = cast<CastExpr>(E)->getSubExpr(); 2489 goto tryAgain; 2490 2491 case Stmt::ParenExprClass: 2492 E = cast<ParenExpr>(E)->getSubExpr(); 2493 goto tryAgain; 2494 } 2495} 2496 2497CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2498 // When visiting children for destructors we want to visit them in reverse 2499 // order. Because there's no reverse iterator for children must to reverse 2500 // them in helper vector. 2501 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2502 ChildrenVect ChildrenRev; 2503 for (Stmt::child_iterator I = E->child_begin(), L = E->child_end(); 2504 I != L; ++I) { 2505 if (*I) ChildrenRev.push_back(*I); 2506 } 2507 2508 CFGBlock *B = Block; 2509 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2510 L = ChildrenRev.rend(); I != L; ++I) { 2511 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2512 B = R; 2513 } 2514 return B; 2515} 2516 2517CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2518 if (E->isLogicalOp()) { 2519 // Destructors for temporaries in LHS expression should be called after 2520 // those for RHS expression. Even if this will unnecessarily create a block, 2521 // this block will be used at least by the full expression. 2522 autoCreateBlock(); 2523 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2524 if (badCFG) 2525 return NULL; 2526 2527 Succ = ConfluenceBlock; 2528 Block = NULL; 2529 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2530 2531 if (RHSBlock) { 2532 if (badCFG) 2533 return NULL; 2534 2535 // If RHS expression did produce destructors we need to connect created 2536 // blocks to CFG in same manner as for binary operator itself. 2537 CFGBlock *LHSBlock = createBlock(false); 2538 LHSBlock->setTerminator(CFGTerminator(E, true)); 2539 2540 // For binary operator LHS block is before RHS in list of predecessors 2541 // of ConfluenceBlock. 2542 std::reverse(ConfluenceBlock->pred_begin(), 2543 ConfluenceBlock->pred_end()); 2544 2545 // See if this is a known constant. 2546 TryResult KnownVal = TryEvaluateBool(E->getLHS()); 2547 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2548 KnownVal.negate(); 2549 2550 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2551 // itself. 2552 if (E->getOpcode() == BO_LOr) { 2553 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2554 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2555 } else { 2556 assert (E->getOpcode() == BO_LAnd); 2557 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2558 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2559 } 2560 2561 Block = LHSBlock; 2562 return LHSBlock; 2563 } 2564 2565 Block = ConfluenceBlock; 2566 return ConfluenceBlock; 2567 } 2568 2569 if (E->isAssignmentOp()) { 2570 // For assignment operator (=) LHS expression is visited 2571 // before RHS expression. For destructors visit them in reverse order. 2572 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2573 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2574 return LHSBlock ? LHSBlock : RHSBlock; 2575 } 2576 2577 // For any other binary operator RHS expression is visited before 2578 // LHS expression (order of children). For destructors visit them in reverse 2579 // order. 2580 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2581 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2582 return RHSBlock ? RHSBlock : LHSBlock; 2583} 2584 2585CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2586 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2587 // First add destructors for temporaries in subexpression. 2588 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2589 if (!BindToTemporary) { 2590 // If lifetime of temporary is not prolonged (by assigning to constant 2591 // reference) add destructor for it. 2592 autoCreateBlock(); 2593 appendTemporaryDtor(Block, E); 2594 B = Block; 2595 } 2596 return B; 2597} 2598 2599CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2600 ConditionalOperator *E, bool BindToTemporary) { 2601 // First add destructors for condition expression. Even if this will 2602 // unnecessarily create a block, this block will be used at least by the full 2603 // expression. 2604 autoCreateBlock(); 2605 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2606 if (badCFG) 2607 return NULL; 2608 2609 // Try to add block with destructors for LHS expression. 2610 CFGBlock *LHSBlock = NULL; 2611 if (E->getLHS()) { 2612 Succ = ConfluenceBlock; 2613 Block = NULL; 2614 LHSBlock = VisitForTemporaryDtors(E->getLHS(), BindToTemporary); 2615 if (badCFG) 2616 return NULL; 2617 } 2618 2619 // Try to add block with destructors for RHS expression; 2620 Succ = ConfluenceBlock; 2621 Block = NULL; 2622 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), BindToTemporary); 2623 if (badCFG) 2624 return NULL; 2625 2626 if (!RHSBlock && !LHSBlock) { 2627 // If neither LHS nor RHS expression had temporaries to destroy don't create 2628 // more blocks. 2629 Block = ConfluenceBlock; 2630 return Block; 2631 } 2632 2633 Block = createBlock(false); 2634 Block->setTerminator(CFGTerminator(E, true)); 2635 2636 // See if this is a known constant. 2637 const TryResult &KnownVal = TryEvaluateBool(E->getCond()); 2638 2639 if (LHSBlock) { 2640 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2641 } else if (KnownVal.isFalse()) { 2642 AddSuccessor(Block, NULL); 2643 } else { 2644 AddSuccessor(Block, ConfluenceBlock); 2645 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2646 } 2647 2648 if (!RHSBlock) 2649 RHSBlock = ConfluenceBlock; 2650 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2651 2652 return Block; 2653} 2654 2655} // end anonymous namespace 2656 2657/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2658/// no successors or predecessors. If this is the first block created in the 2659/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2660CFGBlock* CFG::createBlock() { 2661 bool first_block = begin() == end(); 2662 2663 // Create the block. 2664 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2665 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2666 Blocks.push_back(Mem, BlkBVC); 2667 2668 // If this is the first block, set it as the Entry and Exit. 2669 if (first_block) 2670 Entry = Exit = &back(); 2671 2672 // Return the block. 2673 return &back(); 2674} 2675 2676/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2677/// CFG is returned to the caller. 2678CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2679 BuildOptions BO) { 2680 CFGBuilder Builder; 2681 return Builder.buildCFG(D, Statement, C, BO); 2682} 2683 2684//===----------------------------------------------------------------------===// 2685// CFG: Queries for BlkExprs. 2686//===----------------------------------------------------------------------===// 2687 2688namespace { 2689 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2690} 2691 2692static void FindSubExprAssignments(Stmt *S, 2693 llvm::SmallPtrSet<Expr*,50>& Set) { 2694 if (!S) 2695 return; 2696 2697 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2698 Stmt *child = *I; 2699 if (!child) 2700 continue; 2701 2702 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2703 if (B->isAssignmentOp()) Set.insert(B); 2704 2705 FindSubExprAssignments(child, Set); 2706 } 2707} 2708 2709static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2710 BlkExprMapTy* M = new BlkExprMapTy(); 2711 2712 // Look for assignments that are used as subexpressions. These are the only 2713 // assignments that we want to *possibly* register as a block-level 2714 // expression. Basically, if an assignment occurs both in a subexpression and 2715 // at the block-level, it is a block-level expression. 2716 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2717 2718 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2719 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2720 if (CFGStmt S = BI->getAs<CFGStmt>()) 2721 FindSubExprAssignments(S, SubExprAssignments); 2722 2723 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2724 2725 // Iterate over the statements again on identify the Expr* and Stmt* at the 2726 // block-level that are block-level expressions. 2727 2728 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2729 CFGStmt CS = BI->getAs<CFGStmt>(); 2730 if (!CS.isValid()) 2731 continue; 2732 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2733 2734 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2735 // Assignment expressions that are not nested within another 2736 // expression are really "statements" whose value is never used by 2737 // another expression. 2738 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2739 continue; 2740 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2741 // Special handling for statement expressions. The last statement in 2742 // the statement expression is also a block-level expr. 2743 const CompoundStmt* C = Terminator->getSubStmt(); 2744 if (!C->body_empty()) { 2745 unsigned x = M->size(); 2746 (*M)[C->body_back()] = x; 2747 } 2748 } 2749 2750 unsigned x = M->size(); 2751 (*M)[Exp] = x; 2752 } 2753 } 2754 2755 // Look at terminators. The condition is a block-level expression. 2756 2757 Stmt* S = (*I)->getTerminatorCondition(); 2758 2759 if (S && M->find(S) == M->end()) { 2760 unsigned x = M->size(); 2761 (*M)[S] = x; 2762 } 2763 } 2764 2765 return M; 2766} 2767 2768CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2769 assert(S != NULL); 2770 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2771 2772 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2773 BlkExprMapTy::iterator I = M->find(S); 2774 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2775} 2776 2777unsigned CFG::getNumBlkExprs() { 2778 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2779 return M->size(); 2780 2781 // We assume callers interested in the number of BlkExprs will want 2782 // the map constructed if it doesn't already exist. 2783 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2784 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2785} 2786 2787//===----------------------------------------------------------------------===// 2788// Filtered walking of the CFG. 2789//===----------------------------------------------------------------------===// 2790 2791bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2792 const CFGBlock *From, const CFGBlock *To) { 2793 2794 if (F.IgnoreDefaultsWithCoveredEnums) { 2795 // If the 'To' has no label or is labeled but the label isn't a 2796 // CaseStmt then filter this edge. 2797 if (const SwitchStmt *S = 2798 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 2799 if (S->isAllEnumCasesCovered()) { 2800 const Stmt *L = To->getLabel(); 2801 if (!L || !isa<CaseStmt>(L)) 2802 return true; 2803 } 2804 } 2805 } 2806 2807 return false; 2808} 2809 2810//===----------------------------------------------------------------------===// 2811// Cleanup: CFG dstor. 2812//===----------------------------------------------------------------------===// 2813 2814CFG::~CFG() { 2815 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2816} 2817 2818//===----------------------------------------------------------------------===// 2819// CFG pretty printing 2820//===----------------------------------------------------------------------===// 2821 2822namespace { 2823 2824class StmtPrinterHelper : public PrinterHelper { 2825 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2826 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2827 StmtMapTy StmtMap; 2828 DeclMapTy DeclMap; 2829 signed CurrentBlock; 2830 unsigned CurrentStmt; 2831 const LangOptions &LangOpts; 2832public: 2833 2834 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2835 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2836 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2837 unsigned j = 1; 2838 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2839 BI != BEnd; ++BI, ++j ) { 2840 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2841 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2842 StmtMap[SE] = P; 2843 2844 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2845 DeclMap[DS->getSingleDecl()] = P; 2846 2847 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2848 if (VarDecl* VD = IS->getConditionVariable()) 2849 DeclMap[VD] = P; 2850 2851 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2852 if (VarDecl* VD = FS->getConditionVariable()) 2853 DeclMap[VD] = P; 2854 2855 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2856 if (VarDecl* VD = WS->getConditionVariable()) 2857 DeclMap[VD] = P; 2858 2859 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2860 if (VarDecl* VD = SS->getConditionVariable()) 2861 DeclMap[VD] = P; 2862 2863 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2864 if (VarDecl* VD = CS->getExceptionDecl()) 2865 DeclMap[VD] = P; 2866 } 2867 } 2868 } 2869 } 2870 } 2871 2872 virtual ~StmtPrinterHelper() {} 2873 2874 const LangOptions &getLangOpts() const { return LangOpts; } 2875 void setBlockID(signed i) { CurrentBlock = i; } 2876 void setStmtID(unsigned i) { CurrentStmt = i; } 2877 2878 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2879 StmtMapTy::iterator I = StmtMap.find(S); 2880 2881 if (I == StmtMap.end()) 2882 return false; 2883 2884 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2885 && I->second.second == CurrentStmt) { 2886 return false; 2887 } 2888 2889 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2890 return true; 2891 } 2892 2893 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2894 DeclMapTy::iterator I = DeclMap.find(D); 2895 2896 if (I == DeclMap.end()) 2897 return false; 2898 2899 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2900 && I->second.second == CurrentStmt) { 2901 return false; 2902 } 2903 2904 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2905 return true; 2906 } 2907}; 2908} // end anonymous namespace 2909 2910 2911namespace { 2912class CFGBlockTerminatorPrint 2913 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2914 2915 llvm::raw_ostream& OS; 2916 StmtPrinterHelper* Helper; 2917 PrintingPolicy Policy; 2918public: 2919 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2920 const PrintingPolicy &Policy) 2921 : OS(os), Helper(helper), Policy(Policy) {} 2922 2923 void VisitIfStmt(IfStmt* I) { 2924 OS << "if "; 2925 I->getCond()->printPretty(OS,Helper,Policy); 2926 } 2927 2928 // Default case. 2929 void VisitStmt(Stmt* Terminator) { 2930 Terminator->printPretty(OS, Helper, Policy); 2931 } 2932 2933 void VisitForStmt(ForStmt* F) { 2934 OS << "for (" ; 2935 if (F->getInit()) 2936 OS << "..."; 2937 OS << "; "; 2938 if (Stmt* C = F->getCond()) 2939 C->printPretty(OS, Helper, Policy); 2940 OS << "; "; 2941 if (F->getInc()) 2942 OS << "..."; 2943 OS << ")"; 2944 } 2945 2946 void VisitWhileStmt(WhileStmt* W) { 2947 OS << "while " ; 2948 if (Stmt* C = W->getCond()) 2949 C->printPretty(OS, Helper, Policy); 2950 } 2951 2952 void VisitDoStmt(DoStmt* D) { 2953 OS << "do ... while "; 2954 if (Stmt* C = D->getCond()) 2955 C->printPretty(OS, Helper, Policy); 2956 } 2957 2958 void VisitSwitchStmt(SwitchStmt* Terminator) { 2959 OS << "switch "; 2960 Terminator->getCond()->printPretty(OS, Helper, Policy); 2961 } 2962 2963 void VisitCXXTryStmt(CXXTryStmt* CS) { 2964 OS << "try ..."; 2965 } 2966 2967 void VisitConditionalOperator(ConditionalOperator* C) { 2968 C->getCond()->printPretty(OS, Helper, Policy); 2969 OS << " ? ... : ..."; 2970 } 2971 2972 void VisitChooseExpr(ChooseExpr* C) { 2973 OS << "__builtin_choose_expr( "; 2974 C->getCond()->printPretty(OS, Helper, Policy); 2975 OS << " )"; 2976 } 2977 2978 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2979 OS << "goto *"; 2980 I->getTarget()->printPretty(OS, Helper, Policy); 2981 } 2982 2983 void VisitBinaryOperator(BinaryOperator* B) { 2984 if (!B->isLogicalOp()) { 2985 VisitExpr(B); 2986 return; 2987 } 2988 2989 B->getLHS()->printPretty(OS, Helper, Policy); 2990 2991 switch (B->getOpcode()) { 2992 case BO_LOr: 2993 OS << " || ..."; 2994 return; 2995 case BO_LAnd: 2996 OS << " && ..."; 2997 return; 2998 default: 2999 assert(false && "Invalid logical operator."); 3000 } 3001 } 3002 3003 void VisitExpr(Expr* E) { 3004 E->printPretty(OS, Helper, Policy); 3005 } 3006}; 3007} // end anonymous namespace 3008 3009static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3010 const CFGElement &E) { 3011 if (CFGStmt CS = E.getAs<CFGStmt>()) { 3012 Stmt *S = CS; 3013 3014 if (Helper) { 3015 3016 // special printing for statement-expressions. 3017 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3018 CompoundStmt* Sub = SE->getSubStmt(); 3019 3020 if (Sub->child_begin() != Sub->child_end()) { 3021 OS << "({ ... ; "; 3022 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3023 OS << " })\n"; 3024 return; 3025 } 3026 } 3027 // special printing for comma expressions. 3028 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3029 if (B->getOpcode() == BO_Comma) { 3030 OS << "... , "; 3031 Helper->handledStmt(B->getRHS(),OS); 3032 OS << '\n'; 3033 return; 3034 } 3035 } 3036 } 3037 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3038 3039 if (isa<CXXOperatorCallExpr>(S)) { 3040 OS << " (OperatorCall)"; 3041 } else if (isa<CXXBindTemporaryExpr>(S)) { 3042 OS << " (BindTemporary)"; 3043 } 3044 3045 // Expressions need a newline. 3046 if (isa<Expr>(S)) 3047 OS << '\n'; 3048 3049 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 3050 CXXBaseOrMemberInitializer* I = IE; 3051 if (I->isBaseInitializer()) 3052 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3053 else OS << I->getAnyMember()->getName(); 3054 3055 OS << "("; 3056 if (Expr* IE = I->getInit()) 3057 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3058 OS << ")"; 3059 3060 if (I->isBaseInitializer()) 3061 OS << " (Base initializer)\n"; 3062 else OS << " (Member initializer)\n"; 3063 3064 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 3065 VarDecl* VD = DE.getVarDecl(); 3066 Helper->handleDecl(VD, OS); 3067 3068 const Type* T = VD->getType().getTypePtr(); 3069 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3070 T = RT->getPointeeType().getTypePtr(); 3071 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3072 T = ET; 3073 3074 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3075 OS << " (Implicit destructor)\n"; 3076 3077 } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { 3078 const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); 3079 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3080 OS << " (Base object destructor)\n"; 3081 3082 } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { 3083 FieldDecl *FD = ME.getFieldDecl(); 3084 3085 const Type *T = FD->getType().getTypePtr(); 3086 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3087 T = ET; 3088 3089 OS << "this->" << FD->getName(); 3090 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3091 OS << " (Member object destructor)\n"; 3092 3093 } else if (CFGTemporaryDtor TE = E.getAs<CFGTemporaryDtor>()) { 3094 CXXBindTemporaryExpr *BT = TE.getBindTemporaryExpr(); 3095 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3096 OS << " (Temporary object destructor)\n"; 3097 } 3098} 3099 3100static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3101 const CFGBlock& B, 3102 StmtPrinterHelper* Helper, bool print_edges) { 3103 3104 if (Helper) Helper->setBlockID(B.getBlockID()); 3105 3106 // Print the header. 3107 OS << "\n [ B" << B.getBlockID(); 3108 3109 if (&B == &cfg->getEntry()) 3110 OS << " (ENTRY) ]\n"; 3111 else if (&B == &cfg->getExit()) 3112 OS << " (EXIT) ]\n"; 3113 else if (&B == cfg->getIndirectGotoBlock()) 3114 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3115 else 3116 OS << " ]\n"; 3117 3118 // Print the label of this block. 3119 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3120 3121 if (print_edges) 3122 OS << " "; 3123 3124 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3125 OS << L->getName(); 3126 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3127 OS << "case "; 3128 C->getLHS()->printPretty(OS, Helper, 3129 PrintingPolicy(Helper->getLangOpts())); 3130 if (C->getRHS()) { 3131 OS << " ... "; 3132 C->getRHS()->printPretty(OS, Helper, 3133 PrintingPolicy(Helper->getLangOpts())); 3134 } 3135 } else if (isa<DefaultStmt>(Label)) 3136 OS << "default"; 3137 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3138 OS << "catch ("; 3139 if (CS->getExceptionDecl()) 3140 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3141 0); 3142 else 3143 OS << "..."; 3144 OS << ")"; 3145 3146 } else 3147 assert(false && "Invalid label statement in CFGBlock."); 3148 3149 OS << ":\n"; 3150 } 3151 3152 // Iterate through the statements in the block and print them. 3153 unsigned j = 1; 3154 3155 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3156 I != E ; ++I, ++j ) { 3157 3158 // Print the statement # in the basic block and the statement itself. 3159 if (print_edges) 3160 OS << " "; 3161 3162 OS << llvm::format("%3d", j) << ": "; 3163 3164 if (Helper) 3165 Helper->setStmtID(j); 3166 3167 print_elem(OS,Helper,*I); 3168 } 3169 3170 // Print the terminator of this block. 3171 if (B.getTerminator()) { 3172 if (print_edges) 3173 OS << " "; 3174 3175 OS << " T: "; 3176 3177 if (Helper) Helper->setBlockID(-1); 3178 3179 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3180 PrintingPolicy(Helper->getLangOpts())); 3181 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3182 OS << '\n'; 3183 } 3184 3185 if (print_edges) { 3186 // Print the predecessors of this block. 3187 OS << " Predecessors (" << B.pred_size() << "):"; 3188 unsigned i = 0; 3189 3190 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3191 I != E; ++I, ++i) { 3192 3193 if (i == 8 || (i-8) == 0) 3194 OS << "\n "; 3195 3196 OS << " B" << (*I)->getBlockID(); 3197 } 3198 3199 OS << '\n'; 3200 3201 // Print the successors of this block. 3202 OS << " Successors (" << B.succ_size() << "):"; 3203 i = 0; 3204 3205 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3206 I != E; ++I, ++i) { 3207 3208 if (i == 8 || (i-8) % 10 == 0) 3209 OS << "\n "; 3210 3211 if (*I) 3212 OS << " B" << (*I)->getBlockID(); 3213 else 3214 OS << " NULL"; 3215 } 3216 3217 OS << '\n'; 3218 } 3219} 3220 3221 3222/// dump - A simple pretty printer of a CFG that outputs to stderr. 3223void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3224 3225/// print - A simple pretty printer of a CFG that outputs to an ostream. 3226void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3227 StmtPrinterHelper Helper(this, LO); 3228 3229 // Print the entry block. 3230 print_block(OS, this, getEntry(), &Helper, true); 3231 3232 // Iterate through the CFGBlocks and print them one by one. 3233 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3234 // Skip the entry block, because we already printed it. 3235 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3236 continue; 3237 3238 print_block(OS, this, **I, &Helper, true); 3239 } 3240 3241 // Print the exit block. 3242 print_block(OS, this, getExit(), &Helper, true); 3243 OS.flush(); 3244} 3245 3246/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3247void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3248 print(llvm::errs(), cfg, LO); 3249} 3250 3251/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3252/// Generally this will only be called from CFG::print. 3253void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3254 const LangOptions &LO) const { 3255 StmtPrinterHelper Helper(cfg, LO); 3256 print_block(OS, cfg, *this, &Helper, true); 3257} 3258 3259/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3260void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3261 const LangOptions &LO) const { 3262 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3263 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3264} 3265 3266Stmt* CFGBlock::getTerminatorCondition() { 3267 Stmt *Terminator = this->Terminator; 3268 if (!Terminator) 3269 return NULL; 3270 3271 Expr* E = NULL; 3272 3273 switch (Terminator->getStmtClass()) { 3274 default: 3275 break; 3276 3277 case Stmt::ForStmtClass: 3278 E = cast<ForStmt>(Terminator)->getCond(); 3279 break; 3280 3281 case Stmt::WhileStmtClass: 3282 E = cast<WhileStmt>(Terminator)->getCond(); 3283 break; 3284 3285 case Stmt::DoStmtClass: 3286 E = cast<DoStmt>(Terminator)->getCond(); 3287 break; 3288 3289 case Stmt::IfStmtClass: 3290 E = cast<IfStmt>(Terminator)->getCond(); 3291 break; 3292 3293 case Stmt::ChooseExprClass: 3294 E = cast<ChooseExpr>(Terminator)->getCond(); 3295 break; 3296 3297 case Stmt::IndirectGotoStmtClass: 3298 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3299 break; 3300 3301 case Stmt::SwitchStmtClass: 3302 E = cast<SwitchStmt>(Terminator)->getCond(); 3303 break; 3304 3305 case Stmt::ConditionalOperatorClass: 3306 E = cast<ConditionalOperator>(Terminator)->getCond(); 3307 break; 3308 3309 case Stmt::BinaryOperatorClass: // '&&' and '||' 3310 E = cast<BinaryOperator>(Terminator)->getLHS(); 3311 break; 3312 3313 case Stmt::ObjCForCollectionStmtClass: 3314 return Terminator; 3315 } 3316 3317 return E ? E->IgnoreParens() : NULL; 3318} 3319 3320bool CFGBlock::hasBinaryBranchTerminator() const { 3321 const Stmt *Terminator = this->Terminator; 3322 if (!Terminator) 3323 return false; 3324 3325 Expr* E = NULL; 3326 3327 switch (Terminator->getStmtClass()) { 3328 default: 3329 return false; 3330 3331 case Stmt::ForStmtClass: 3332 case Stmt::WhileStmtClass: 3333 case Stmt::DoStmtClass: 3334 case Stmt::IfStmtClass: 3335 case Stmt::ChooseExprClass: 3336 case Stmt::ConditionalOperatorClass: 3337 case Stmt::BinaryOperatorClass: 3338 return true; 3339 } 3340 3341 return E ? E->IgnoreParens() : NULL; 3342} 3343 3344 3345//===----------------------------------------------------------------------===// 3346// CFG Graphviz Visualization 3347//===----------------------------------------------------------------------===// 3348 3349 3350#ifndef NDEBUG 3351static StmtPrinterHelper* GraphHelper; 3352#endif 3353 3354void CFG::viewCFG(const LangOptions &LO) const { 3355#ifndef NDEBUG 3356 StmtPrinterHelper H(this, LO); 3357 GraphHelper = &H; 3358 llvm::ViewGraph(this,"CFG"); 3359 GraphHelper = NULL; 3360#endif 3361} 3362 3363namespace llvm { 3364template<> 3365struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3366 3367 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3368 3369 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3370 3371#ifndef NDEBUG 3372 std::string OutSStr; 3373 llvm::raw_string_ostream Out(OutSStr); 3374 print_block(Out,Graph, *Node, GraphHelper, false); 3375 std::string& OutStr = Out.str(); 3376 3377 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3378 3379 // Process string output to make it nicer... 3380 for (unsigned i = 0; i != OutStr.length(); ++i) 3381 if (OutStr[i] == '\n') { // Left justify 3382 OutStr[i] = '\\'; 3383 OutStr.insert(OutStr.begin()+i+1, 'l'); 3384 } 3385 3386 return OutStr; 3387#else 3388 return ""; 3389#endif 3390 } 3391}; 3392} // end namespace llvm 3393