CFG.cpp revision 00eb3f9c5b33e3d99aee1f8b75dd9c9678fdd66b
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39/// The CFG builder uses a recursive algorithm to build the CFG. When 40/// we process an expression, sometimes we know that we must add the 41/// subexpressions as block-level expressions. For example: 42/// 43/// exp1 || exp2 44/// 45/// When processing the '||' expression, we know that exp1 and exp2 46/// need to be added as block-level expressions, even though they 47/// might not normally need to be. AddStmtChoice records this 48/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 49/// the builder has an option not to add a subexpression as a 50/// block-level expression. 51/// 52/// The lvalue bit captures whether or not a subexpression needs to 53/// be processed as an lvalue. That information needs to be recorded 54/// in the CFG for block-level expressions so that analyses do the 55/// right thing when traversing the CFG (since such subexpressions 56/// will be seen before their parent expression is processed). 57class AddStmtChoice { 58public: 59 enum Kind { NotAlwaysAdd = 0, 60 AlwaysAdd = 1, 61 AsLValueNotAlwaysAdd = 2, 62 AsLValueAlwaysAdd = 3 }; 63 64 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 65 66 bool alwaysAdd() const { return kind & AlwaysAdd; } 67 bool asLValue() const { return kind >= AsLValueNotAlwaysAdd; } 68 69 /// Return a copy of this object, except with the 'always-add' bit 70 /// set as specified. 71 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 72 return AddStmtChoice(alwaysAdd ? Kind(kind | AlwaysAdd) : 73 Kind(kind & ~AlwaysAdd)); 74 } 75 76 /// Return a copy of this object, except with the 'as-lvalue' bit 77 /// set as specified. 78 AddStmtChoice withAsLValue(bool asLVal) const { 79 return AddStmtChoice(asLVal ? Kind(kind | AsLValueNotAlwaysAdd) : 80 Kind(kind & ~AsLValueNotAlwaysAdd)); 81 } 82 83private: 84 Kind kind; 85}; 86 87/// LocalScope - Node in tree of local scopes created for C++ implicit 88/// destructor calls generation. It contains list of automatic variables 89/// declared in the scope and link to position in previous scope this scope 90/// began in. 91/// 92/// The process of creating local scopes is as follows: 93/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 94/// - Before processing statements in scope (e.g. CompoundStmt) create 95/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 96/// and set CFGBuilder::ScopePos to the end of new scope, 97/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 98/// at this VarDecl, 99/// - For every normal (without jump) end of scope add to CFGBlock destructors 100/// for objects in the current scope, 101/// - For every jump add to CFGBlock destructors for objects 102/// between CFGBuilder::ScopePos and local scope position saved for jump 103/// target. Thanks to C++ restrictions on goto jumps we can be sure that 104/// jump target position will be on the path to root from CFGBuilder::ScopePos 105/// (adding any variable that doesn't need constructor to be called to 106/// LocalScope can break this assumption), 107/// 108class LocalScope { 109public: 110 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 111 112 /// const_iterator - Iterates local scope backwards and jumps to previous 113 /// scope on reaching the beginning of currently iterated scope. 114 class const_iterator { 115 const LocalScope* Scope; 116 117 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 118 /// Invalid iterator (with null Scope) has VarIter equal to 0. 119 unsigned VarIter; 120 121 public: 122 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 123 /// Incrementing invalid iterator is allowed and will result in invalid 124 /// iterator. 125 const_iterator() 126 : Scope(NULL), VarIter(0) {} 127 128 /// Create valid iterator. In case when S.Prev is an invalid iterator and 129 /// I is equal to 0, this will create invalid iterator. 130 const_iterator(const LocalScope& S, unsigned I) 131 : Scope(&S), VarIter(I) { 132 // Iterator to "end" of scope is not allowed. Handle it by going up 133 // in scopes tree possibly up to invalid iterator in the root. 134 if (VarIter == 0 && Scope) 135 *this = Scope->Prev; 136 } 137 138 VarDecl* const* operator->() const { 139 assert (Scope && "Dereferencing invalid iterator is not allowed"); 140 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 141 return &Scope->Vars[VarIter - 1]; 142 } 143 VarDecl* operator*() const { 144 return *this->operator->(); 145 } 146 147 const_iterator& operator++() { 148 if (!Scope) 149 return *this; 150 151 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 152 --VarIter; 153 if (VarIter == 0) 154 *this = Scope->Prev; 155 return *this; 156 } 157 const_iterator operator++(int) { 158 const_iterator P = *this; 159 ++*this; 160 return P; 161 } 162 163 bool operator==(const const_iterator& rhs) const { 164 return Scope == rhs.Scope && VarIter == rhs.VarIter; 165 } 166 bool operator!=(const const_iterator& rhs) const { 167 return !(*this == rhs); 168 } 169 170 operator bool() const { 171 return *this != const_iterator(); 172 } 173 174 int distance(const_iterator L); 175 }; 176 177 friend class const_iterator; 178 179private: 180 /// Automatic variables in order of declaration. 181 AutomaticVarsTy Vars; 182 /// Iterator to variable in previous scope that was declared just before 183 /// begin of this scope. 184 const_iterator Prev; 185 186public: 187 /// Constructs empty scope linked to previous scope in specified place. 188 LocalScope(const_iterator P) 189 : Vars() 190 , Prev(P) {} 191 192 /// Begin of scope in direction of CFG building (backwards). 193 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 194 195 void addVar(VarDecl* VD) { 196 Vars.push_back(VD); 197 } 198}; 199 200/// distance - Calculates distance from this to L. L must be reachable from this 201/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 202/// number of scopes between this and L. 203int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 204 int D = 0; 205 const_iterator F = *this; 206 while (F.Scope != L.Scope) { 207 assert (F != const_iterator() 208 && "L iterator is not reachable from F iterator."); 209 D += F.VarIter; 210 F = F.Scope->Prev; 211 } 212 D += F.VarIter - L.VarIter; 213 return D; 214} 215 216/// BlockScopePosPair - Structure for specifying position in CFG during its 217/// build process. It consists of CFGBlock that specifies position in CFG graph 218/// and LocalScope::const_iterator that specifies position in LocalScope graph. 219struct BlockScopePosPair { 220 BlockScopePosPair() {} 221 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 222 : Block(B), ScopePos(S) {} 223 224 CFGBlock* Block; 225 LocalScope::const_iterator ScopePos; 226}; 227 228/// CFGBuilder - This class implements CFG construction from an AST. 229/// The builder is stateful: an instance of the builder should be used to only 230/// construct a single CFG. 231/// 232/// Example usage: 233/// 234/// CFGBuilder builder; 235/// CFG* cfg = builder.BuildAST(stmt1); 236/// 237/// CFG construction is done via a recursive walk of an AST. We actually parse 238/// the AST in reverse order so that the successor of a basic block is 239/// constructed prior to its predecessor. This allows us to nicely capture 240/// implicit fall-throughs without extra basic blocks. 241/// 242class CFGBuilder { 243 typedef BlockScopePosPair JumpTarget; 244 typedef BlockScopePosPair JumpSource; 245 246 ASTContext *Context; 247 llvm::OwningPtr<CFG> cfg; 248 249 CFGBlock* Block; 250 CFGBlock* Succ; 251 JumpTarget ContinueJumpTarget; 252 JumpTarget BreakJumpTarget; 253 CFGBlock* SwitchTerminatedBlock; 254 CFGBlock* DefaultCaseBlock; 255 CFGBlock* TryTerminatedBlock; 256 257 // Current position in local scope. 258 LocalScope::const_iterator ScopePos; 259 260 // LabelMap records the mapping from Label expressions to their jump targets. 261 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 262 LabelMapTy LabelMap; 263 264 // A list of blocks that end with a "goto" that must be backpatched to their 265 // resolved targets upon completion of CFG construction. 266 typedef std::vector<JumpSource> BackpatchBlocksTy; 267 BackpatchBlocksTy BackpatchBlocks; 268 269 // A list of labels whose address has been taken (for indirect gotos). 270 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 271 LabelSetTy AddressTakenLabels; 272 273 bool badCFG; 274 CFG::BuildOptions BuildOpts; 275 276public: 277 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 278 Block(NULL), Succ(NULL), 279 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 280 TryTerminatedBlock(NULL), badCFG(false) {} 281 282 // buildCFG - Used by external clients to construct the CFG. 283 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 284 CFG::BuildOptions BO); 285 286private: 287 // Visitors to walk an AST and construct the CFG. 288 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 289 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 290 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 291 CFGBlock *VisitBreakStmt(BreakStmt *B); 292 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 293 CFGBlock *VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E, 294 AddStmtChoice asc); 295 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 296 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 297 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 298 AddStmtChoice asc); 299 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 300 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 301 AddStmtChoice asc); 302 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 303 AddStmtChoice asc); 304 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 305 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 306 CFGBlock *VisitCaseStmt(CaseStmt *C); 307 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 308 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 309 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 310 CFGBlock *VisitContinueStmt(ContinueStmt *C); 311 CFGBlock *VisitDeclStmt(DeclStmt *DS); 312 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 313 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 314 CFGBlock *VisitDoStmt(DoStmt *D); 315 CFGBlock *VisitForStmt(ForStmt *F); 316 CFGBlock *VisitGotoStmt(GotoStmt* G); 317 CFGBlock *VisitIfStmt(IfStmt *I); 318 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 319 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 320 CFGBlock *VisitLabelStmt(LabelStmt *L); 321 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 322 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 323 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 324 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 325 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 326 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 327 CFGBlock *VisitReturnStmt(ReturnStmt* R); 328 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 329 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 330 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 331 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 332 CFGBlock *VisitWhileStmt(WhileStmt *W); 333 334 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 335 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 336 CFGBlock *VisitChildren(Stmt* S); 337 338 // Visitors to walk an AST and generate destructors of temporaries in 339 // full expression. 340 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 341 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 342 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 343 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 344 bool BindToTemporary); 345 CFGBlock *VisitConditionalOperatorForTemporaryDtors(ConditionalOperator *E, 346 bool BindToTemporary); 347 348 // NYS == Not Yet Supported 349 CFGBlock* NYS() { 350 badCFG = true; 351 return Block; 352 } 353 354 void autoCreateBlock() { if (!Block) Block = createBlock(); } 355 CFGBlock *createBlock(bool add_successor = true); 356 357 CFGBlock *addStmt(Stmt *S) { 358 return Visit(S, AddStmtChoice::AlwaysAdd); 359 } 360 CFGBlock *addInitializer(CXXBaseOrMemberInitializer *I); 361 void addAutomaticObjDtors(LocalScope::const_iterator B, 362 LocalScope::const_iterator E, Stmt* S); 363 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 364 365 // Local scopes creation. 366 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 367 368 void addLocalScopeForStmt(Stmt* S); 369 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 370 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 371 372 void addLocalScopeAndDtors(Stmt* S); 373 374 // Interface to CFGBlock - adding CFGElements. 375 void AppendStmt(CFGBlock *B, Stmt *S, 376 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 377 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 378 } 379 void appendInitializer(CFGBlock *B, CXXBaseOrMemberInitializer *I) { 380 B->appendInitializer(I, cfg->getBumpVectorContext()); 381 } 382 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 383 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 384 } 385 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 386 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 387 } 388 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 389 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 390 } 391 392 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 393 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 394 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 395 LocalScope::const_iterator E, Stmt* S); 396 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 397 LocalScope::const_iterator B, LocalScope::const_iterator E); 398 399 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 400 B->addSuccessor(S, cfg->getBumpVectorContext()); 401 } 402 403 /// TryResult - a class representing a variant over the values 404 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 405 /// and is used by the CFGBuilder to decide if a branch condition 406 /// can be decided up front during CFG construction. 407 class TryResult { 408 int X; 409 public: 410 TryResult(bool b) : X(b ? 1 : 0) {} 411 TryResult() : X(-1) {} 412 413 bool isTrue() const { return X == 1; } 414 bool isFalse() const { return X == 0; } 415 bool isKnown() const { return X >= 0; } 416 void negate() { 417 assert(isKnown()); 418 X ^= 0x1; 419 } 420 }; 421 422 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 423 /// if we can evaluate to a known value, otherwise return -1. 424 TryResult TryEvaluateBool(Expr *S) { 425 if (!BuildOpts.PruneTriviallyFalseEdges) 426 return TryResult(); 427 428 Expr::EvalResult Result; 429 if (!S->isTypeDependent() && !S->isValueDependent() && 430 S->Evaluate(Result, *Context) && Result.Val.isInt()) 431 return Result.Val.getInt().getBoolValue(); 432 433 return TryResult(); 434 } 435}; 436 437// FIXME: Add support for dependent-sized array types in C++? 438// Does it even make sense to build a CFG for an uninstantiated template? 439static VariableArrayType* FindVA(Type* t) { 440 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 441 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 442 if (vat->getSizeExpr()) 443 return vat; 444 445 t = vt->getElementType().getTypePtr(); 446 } 447 448 return 0; 449} 450 451/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 452/// arbitrary statement. Examples include a single expression or a function 453/// body (compound statement). The ownership of the returned CFG is 454/// transferred to the caller. If CFG construction fails, this method returns 455/// NULL. 456CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 457 CFG::BuildOptions BO) { 458 459 Context = C; 460 assert(cfg.get()); 461 if (!Statement) 462 return NULL; 463 464 BuildOpts = BO; 465 466 // Create an empty block that will serve as the exit block for the CFG. Since 467 // this is the first block added to the CFG, it will be implicitly registered 468 // as the exit block. 469 Succ = createBlock(); 470 assert(Succ == &cfg->getExit()); 471 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 472 473 if (BuildOpts.AddImplicitDtors) 474 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 475 addImplicitDtorsForDestructor(DD); 476 477 // Visit the statements and create the CFG. 478 CFGBlock *B = addStmt(Statement); 479 480 if (badCFG) 481 return NULL; 482 483 // For C++ constructor add initializers to CFG. 484 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 485 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 486 E = CD->init_rend(); I != E; ++I) { 487 B = addInitializer(*I); 488 if (badCFG) 489 return NULL; 490 } 491 } 492 493 if (B) 494 Succ = B; 495 496 // Backpatch the gotos whose label -> block mappings we didn't know when we 497 // encountered them. 498 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 499 E = BackpatchBlocks.end(); I != E; ++I ) { 500 501 CFGBlock* B = I->Block; 502 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 503 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 504 505 // If there is no target for the goto, then we are looking at an 506 // incomplete AST. Handle this by not registering a successor. 507 if (LI == LabelMap.end()) continue; 508 509 JumpTarget JT = LI->second; 510 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 511 AddSuccessor(B, JT.Block); 512 } 513 514 // Add successors to the Indirect Goto Dispatch block (if we have one). 515 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 516 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 517 E = AddressTakenLabels.end(); I != E; ++I ) { 518 519 // Lookup the target block. 520 LabelMapTy::iterator LI = LabelMap.find(*I); 521 522 // If there is no target block that contains label, then we are looking 523 // at an incomplete AST. Handle this by not registering a successor. 524 if (LI == LabelMap.end()) continue; 525 526 AddSuccessor(B, LI->second.Block); 527 } 528 529 // Create an empty entry block that has no predecessors. 530 cfg->setEntry(createBlock()); 531 532 return cfg.take(); 533} 534 535/// createBlock - Used to lazily create blocks that are connected 536/// to the current (global) succcessor. 537CFGBlock* CFGBuilder::createBlock(bool add_successor) { 538 CFGBlock* B = cfg->createBlock(); 539 if (add_successor && Succ) 540 AddSuccessor(B, Succ); 541 return B; 542} 543 544/// addInitializer - Add C++ base or member initializer element to CFG. 545CFGBlock *CFGBuilder::addInitializer(CXXBaseOrMemberInitializer *I) { 546 if (!BuildOpts.AddInitializers) 547 return Block; 548 549 bool IsReference = false; 550 bool HasTemporaries = false; 551 552 // Destructors of temporaries in initialization expression should be called 553 // after initialization finishes. 554 Expr *Init = I->getInit(); 555 if (Init) { 556 if (FieldDecl *FD = I->getAnyMember()) 557 IsReference = FD->getType()->isReferenceType(); 558 HasTemporaries = isa<CXXExprWithTemporaries>(Init); 559 560 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 561 // Generate destructors for temporaries in initialization expression. 562 VisitForTemporaryDtors(cast<CXXExprWithTemporaries>(Init)->getSubExpr(), 563 IsReference); 564 } 565 } 566 567 autoCreateBlock(); 568 appendInitializer(Block, I); 569 570 if (Init) { 571 AddStmtChoice asc = AddStmtChoice().withAsLValue(IsReference); 572 if (HasTemporaries) 573 // For expression with temporaries go directly to subexpression to omit 574 // generating destructors for the second time. 575 return Visit(cast<CXXExprWithTemporaries>(Init)->getSubExpr(), asc); 576 return Visit(Init, asc); 577 } 578 579 return Block; 580} 581 582/// addAutomaticObjDtors - Add to current block automatic objects destructors 583/// for objects in range of local scope positions. Use S as trigger statement 584/// for destructors. 585void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 586 LocalScope::const_iterator E, Stmt* S) { 587 if (!BuildOpts.AddImplicitDtors) 588 return; 589 590 if (B == E) 591 return; 592 593 autoCreateBlock(); 594 appendAutomaticObjDtors(Block, B, E, S); 595} 596 597/// addImplicitDtorsForDestructor - Add implicit destructors generated for 598/// base and member objects in destructor. 599void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 600 assert (BuildOpts.AddImplicitDtors 601 && "Can be called only when dtors should be added"); 602 const CXXRecordDecl *RD = DD->getParent(); 603 604 // At the end destroy virtual base objects. 605 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 606 VE = RD->vbases_end(); VI != VE; ++VI) { 607 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 608 if (!CD->hasTrivialDestructor()) { 609 autoCreateBlock(); 610 appendBaseDtor(Block, VI); 611 } 612 } 613 614 // Before virtual bases destroy direct base objects. 615 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 616 BE = RD->bases_end(); BI != BE; ++BI) { 617 if (!BI->isVirtual()) { 618 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 619 if (!CD->hasTrivialDestructor()) { 620 autoCreateBlock(); 621 appendBaseDtor(Block, BI); 622 } 623 } 624 } 625 626 // First destroy member objects. 627 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 628 FE = RD->field_end(); FI != FE; ++FI) { 629 // Check for constant size array. Set type to array element type. 630 QualType QT = FI->getType(); 631 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 632 if (AT->getSize() == 0) 633 continue; 634 QT = AT->getElementType(); 635 } 636 637 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 638 if (!CD->hasTrivialDestructor()) { 639 autoCreateBlock(); 640 appendMemberDtor(Block, *FI); 641 } 642 } 643} 644 645/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 646/// way return valid LocalScope object. 647LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 648 if (!Scope) { 649 Scope = cfg->getAllocator().Allocate<LocalScope>(); 650 new (Scope) LocalScope(ScopePos); 651 } 652 return Scope; 653} 654 655/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 656/// that should create implicit scope (e.g. if/else substatements). 657void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 658 if (!BuildOpts.AddImplicitDtors) 659 return; 660 661 LocalScope *Scope = 0; 662 663 // For compound statement we will be creating explicit scope. 664 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 665 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 666 ; BI != BE; ++BI) { 667 Stmt* SI = *BI; 668 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 669 SI = LS->getSubStmt(); 670 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 671 Scope = addLocalScopeForDeclStmt(DS, Scope); 672 } 673 return; 674 } 675 676 // For any other statement scope will be implicit and as such will be 677 // interesting only for DeclStmt. 678 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 679 S = LS->getSubStmt(); 680 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 681 addLocalScopeForDeclStmt(DS); 682} 683 684/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 685/// reuse Scope if not NULL. 686LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 687 LocalScope* Scope) { 688 if (!BuildOpts.AddImplicitDtors) 689 return Scope; 690 691 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 692 ; DI != DE; ++DI) { 693 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 694 Scope = addLocalScopeForVarDecl(VD, Scope); 695 } 696 return Scope; 697} 698 699/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 700/// create add scope for automatic objects and temporary objects bound to 701/// const reference. Will reuse Scope if not NULL. 702LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 703 LocalScope* Scope) { 704 if (!BuildOpts.AddImplicitDtors) 705 return Scope; 706 707 // Check if variable is local. 708 switch (VD->getStorageClass()) { 709 case SC_None: 710 case SC_Auto: 711 case SC_Register: 712 break; 713 default: return Scope; 714 } 715 716 // Check for const references bound to temporary. Set type to pointee. 717 QualType QT = VD->getType(); 718 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 719 QT = RT->getPointeeType(); 720 if (!QT.isConstQualified()) 721 return Scope; 722 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 723 return Scope; 724 } 725 726 // Check for constant size array. Set type to array element type. 727 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 728 if (AT->getSize() == 0) 729 return Scope; 730 QT = AT->getElementType(); 731 } 732 733 // Check if type is a C++ class with non-trivial destructor. 734 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 735 if (!CD->hasTrivialDestructor()) { 736 // Add the variable to scope 737 Scope = createOrReuseLocalScope(Scope); 738 Scope->addVar(VD); 739 ScopePos = Scope->begin(); 740 } 741 return Scope; 742} 743 744/// addLocalScopeAndDtors - For given statement add local scope for it and 745/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 746void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 747 if (!BuildOpts.AddImplicitDtors) 748 return; 749 750 LocalScope::const_iterator scopeBeginPos = ScopePos; 751 addLocalScopeForStmt(S); 752 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 753} 754 755/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 756/// automatic storage duration to CFGBlock's elements vector. Insertion will be 757/// performed in place specified with iterator. 758void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 759 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 760 BumpVectorContext& C = cfg->getBumpVectorContext(); 761 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 762 while (B != E) 763 I = Blk->insertAutomaticObjDtor(I, *B++, S); 764} 765 766/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 767/// automatic storage duration to CFGBlock's elements vector. Elements will be 768/// appended to physical end of the vector which happens to be logical 769/// beginning. 770void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 771 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 772 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 773} 774 775/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 776/// variables with automatic storage duration to CFGBlock's elements vector. 777/// Elements will be prepended to physical beginning of the vector which 778/// happens to be logical end. Use blocks terminator as statement that specifies 779/// destructors call site. 780void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 781 LocalScope::const_iterator B, LocalScope::const_iterator E) { 782 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 783} 784 785/// Visit - Walk the subtree of a statement and add extra 786/// blocks for ternary operators, &&, and ||. We also process "," and 787/// DeclStmts (which may contain nested control-flow). 788CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 789tryAgain: 790 if (!S) { 791 badCFG = true; 792 return 0; 793 } 794 switch (S->getStmtClass()) { 795 default: 796 return VisitStmt(S, asc); 797 798 case Stmt::AddrLabelExprClass: 799 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 800 801 case Stmt::BinaryOperatorClass: 802 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 803 804 case Stmt::BlockExprClass: 805 return VisitBlockExpr(cast<BlockExpr>(S), asc); 806 807 case Stmt::BreakStmtClass: 808 return VisitBreakStmt(cast<BreakStmt>(S)); 809 810 case Stmt::CallExprClass: 811 case Stmt::CXXOperatorCallExprClass: 812 return VisitCallExpr(cast<CallExpr>(S), asc); 813 814 case Stmt::CaseStmtClass: 815 return VisitCaseStmt(cast<CaseStmt>(S)); 816 817 case Stmt::ChooseExprClass: 818 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 819 820 case Stmt::CompoundStmtClass: 821 return VisitCompoundStmt(cast<CompoundStmt>(S)); 822 823 case Stmt::ConditionalOperatorClass: 824 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 825 826 case Stmt::ContinueStmtClass: 827 return VisitContinueStmt(cast<ContinueStmt>(S)); 828 829 case Stmt::CStyleCastExprClass: { 830 CastExpr *castExpr = cast<CastExpr>(S); 831 if (castExpr->getCastKind() == CK_LValueToRValue) { 832 // temporary workaround 833 S = castExpr->getSubExpr(); 834 goto tryAgain; 835 } 836 return VisitStmt(S, asc); 837 } 838 839 case Stmt::CXXCatchStmtClass: 840 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 841 842 case Stmt::CXXExprWithTemporariesClass: 843 return VisitCXXExprWithTemporaries(cast<CXXExprWithTemporaries>(S), asc); 844 845 case Stmt::CXXBindTemporaryExprClass: 846 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 847 848 case Stmt::CXXConstructExprClass: 849 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 850 851 case Stmt::CXXFunctionalCastExprClass: 852 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 853 854 case Stmt::CXXTemporaryObjectExprClass: 855 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 856 857 case Stmt::CXXMemberCallExprClass: 858 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 859 860 case Stmt::CXXThrowExprClass: 861 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 862 863 case Stmt::CXXTryStmtClass: 864 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 865 866 case Stmt::DeclStmtClass: 867 return VisitDeclStmt(cast<DeclStmt>(S)); 868 869 case Stmt::DefaultStmtClass: 870 return VisitDefaultStmt(cast<DefaultStmt>(S)); 871 872 case Stmt::DoStmtClass: 873 return VisitDoStmt(cast<DoStmt>(S)); 874 875 case Stmt::ForStmtClass: 876 return VisitForStmt(cast<ForStmt>(S)); 877 878 case Stmt::GotoStmtClass: 879 return VisitGotoStmt(cast<GotoStmt>(S)); 880 881 case Stmt::IfStmtClass: 882 return VisitIfStmt(cast<IfStmt>(S)); 883 884 case Stmt::ImplicitCastExprClass: { 885 ImplicitCastExpr *castExpr = cast<ImplicitCastExpr>(S); 886 if (castExpr->getCastKind() == CK_LValueToRValue) { 887 // temporary workaround 888 S = castExpr->getSubExpr(); 889 goto tryAgain; 890 } 891 return VisitImplicitCastExpr(castExpr, asc); 892 } 893 894 case Stmt::IndirectGotoStmtClass: 895 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 896 897 case Stmt::LabelStmtClass: 898 return VisitLabelStmt(cast<LabelStmt>(S)); 899 900 case Stmt::MemberExprClass: 901 return VisitMemberExpr(cast<MemberExpr>(S), asc); 902 903 case Stmt::ObjCAtCatchStmtClass: 904 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 905 906 case Stmt::ObjCAtSynchronizedStmtClass: 907 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 908 909 case Stmt::ObjCAtThrowStmtClass: 910 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 911 912 case Stmt::ObjCAtTryStmtClass: 913 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 914 915 case Stmt::ObjCForCollectionStmtClass: 916 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 917 918 case Stmt::ParenExprClass: 919 S = cast<ParenExpr>(S)->getSubExpr(); 920 goto tryAgain; 921 922 case Stmt::NullStmtClass: 923 return Block; 924 925 case Stmt::ReturnStmtClass: 926 return VisitReturnStmt(cast<ReturnStmt>(S)); 927 928 case Stmt::SizeOfAlignOfExprClass: 929 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 930 931 case Stmt::StmtExprClass: 932 return VisitStmtExpr(cast<StmtExpr>(S), asc); 933 934 case Stmt::SwitchStmtClass: 935 return VisitSwitchStmt(cast<SwitchStmt>(S)); 936 937 case Stmt::UnaryOperatorClass: 938 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 939 940 case Stmt::WhileStmtClass: 941 return VisitWhileStmt(cast<WhileStmt>(S)); 942 } 943} 944 945CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 946 if (asc.alwaysAdd()) { 947 autoCreateBlock(); 948 AppendStmt(Block, S, asc); 949 } 950 951 return VisitChildren(S); 952} 953 954/// VisitChildren - Visit the children of a Stmt. 955CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 956 CFGBlock *B = Block; 957 for (Stmt::child_iterator I = Terminator->child_begin(), 958 E = Terminator->child_end(); I != E; ++I) { 959 if (*I) B = Visit(*I); 960 } 961 return B; 962} 963 964CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 965 AddStmtChoice asc) { 966 AddressTakenLabels.insert(A->getLabel()); 967 968 if (asc.alwaysAdd()) { 969 autoCreateBlock(); 970 AppendStmt(Block, A, asc); 971 } 972 973 return Block; 974} 975 976CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 977 AddStmtChoice asc) { 978 if (asc.alwaysAdd()) { 979 autoCreateBlock(); 980 AppendStmt(Block, U, asc); 981 } 982 983 bool asLVal = U->isIncrementDecrementOp(); 984 return Visit(U->getSubExpr(), AddStmtChoice().withAsLValue(asLVal)); 985} 986 987CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 988 AddStmtChoice asc) { 989 if (B->isLogicalOp()) { // && or || 990 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 991 AppendStmt(ConfluenceBlock, B, asc); 992 993 if (badCFG) 994 return 0; 995 996 // create the block evaluating the LHS 997 CFGBlock* LHSBlock = createBlock(false); 998 LHSBlock->setTerminator(B); 999 1000 // create the block evaluating the RHS 1001 Succ = ConfluenceBlock; 1002 Block = NULL; 1003 CFGBlock* RHSBlock = addStmt(B->getRHS()); 1004 1005 if (RHSBlock) { 1006 if (badCFG) 1007 return 0; 1008 } else { 1009 // Create an empty block for cases where the RHS doesn't require 1010 // any explicit statements in the CFG. 1011 RHSBlock = createBlock(); 1012 } 1013 1014 // See if this is a known constant. 1015 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 1016 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1017 KnownVal.negate(); 1018 1019 // Now link the LHSBlock with RHSBlock. 1020 if (B->getOpcode() == BO_LOr) { 1021 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1022 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1023 } else { 1024 assert(B->getOpcode() == BO_LAnd); 1025 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1026 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1027 } 1028 1029 // Generate the blocks for evaluating the LHS. 1030 Block = LHSBlock; 1031 return addStmt(B->getLHS()); 1032 } 1033 1034 if (B->getOpcode() == BO_Comma) { // , 1035 autoCreateBlock(); 1036 AppendStmt(Block, B, asc); 1037 addStmt(B->getRHS()); 1038 return addStmt(B->getLHS()); 1039 } 1040 1041 if (B->isAssignmentOp()) { 1042 if (asc.alwaysAdd()) { 1043 autoCreateBlock(); 1044 AppendStmt(Block, B, asc); 1045 } 1046 1047 Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 1048 return Visit(B->getRHS()); 1049 } 1050 1051 if (asc.alwaysAdd()) { 1052 autoCreateBlock(); 1053 AppendStmt(Block, B, asc); 1054 } 1055 1056 CFGBlock *RBlock = Visit(B->getRHS()); 1057 CFGBlock *LBlock = Visit(B->getLHS()); 1058 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1059 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1060 // return RBlock. Otherwise we'll incorrectly return NULL. 1061 return (LBlock ? LBlock : RBlock); 1062} 1063 1064CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1065 if (asc.alwaysAdd()) { 1066 autoCreateBlock(); 1067 AppendStmt(Block, E, asc); 1068 } 1069 return Block; 1070} 1071 1072CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1073 // "break" is a control-flow statement. Thus we stop processing the current 1074 // block. 1075 if (badCFG) 1076 return 0; 1077 1078 // Now create a new block that ends with the break statement. 1079 Block = createBlock(false); 1080 Block->setTerminator(B); 1081 1082 // If there is no target for the break, then we are looking at an incomplete 1083 // AST. This means that the CFG cannot be constructed. 1084 if (BreakJumpTarget.Block) { 1085 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 1086 AddSuccessor(Block, BreakJumpTarget.Block); 1087 } else 1088 badCFG = true; 1089 1090 1091 return Block; 1092} 1093 1094static bool CanThrow(Expr *E) { 1095 QualType Ty = E->getType(); 1096 if (Ty->isFunctionPointerType()) 1097 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1098 else if (Ty->isBlockPointerType()) 1099 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1100 1101 const FunctionType *FT = Ty->getAs<FunctionType>(); 1102 if (FT) { 1103 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1104 if (Proto->hasEmptyExceptionSpec()) 1105 return false; 1106 } 1107 return true; 1108} 1109 1110CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1111 // If this is a call to a no-return function, this stops the block here. 1112 bool NoReturn = false; 1113 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 1114 NoReturn = true; 1115 } 1116 1117 bool AddEHEdge = false; 1118 1119 // Languages without exceptions are assumed to not throw. 1120 if (Context->getLangOptions().Exceptions) { 1121 if (BuildOpts.AddEHEdges) 1122 AddEHEdge = true; 1123 } 1124 1125 if (FunctionDecl *FD = C->getDirectCallee()) { 1126 if (FD->hasAttr<NoReturnAttr>()) 1127 NoReturn = true; 1128 if (FD->hasAttr<NoThrowAttr>()) 1129 AddEHEdge = false; 1130 } 1131 1132 if (!CanThrow(C->getCallee())) 1133 AddEHEdge = false; 1134 1135 if (!NoReturn && !AddEHEdge) 1136 return VisitStmt(C, asc.withAlwaysAdd(true)); 1137 1138 if (Block) { 1139 Succ = Block; 1140 if (badCFG) 1141 return 0; 1142 } 1143 1144 Block = createBlock(!NoReturn); 1145 AppendStmt(Block, C, asc); 1146 1147 if (NoReturn) { 1148 // Wire this to the exit block directly. 1149 AddSuccessor(Block, &cfg->getExit()); 1150 } 1151 if (AddEHEdge) { 1152 // Add exceptional edges. 1153 if (TryTerminatedBlock) 1154 AddSuccessor(Block, TryTerminatedBlock); 1155 else 1156 AddSuccessor(Block, &cfg->getExit()); 1157 } 1158 1159 return VisitChildren(C); 1160} 1161 1162CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1163 AddStmtChoice asc) { 1164 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1165 AppendStmt(ConfluenceBlock, C, asc); 1166 if (badCFG) 1167 return 0; 1168 1169 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1170 Succ = ConfluenceBlock; 1171 Block = NULL; 1172 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1173 if (badCFG) 1174 return 0; 1175 1176 Succ = ConfluenceBlock; 1177 Block = NULL; 1178 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1179 if (badCFG) 1180 return 0; 1181 1182 Block = createBlock(false); 1183 // See if this is a known constant. 1184 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1185 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1186 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1187 Block->setTerminator(C); 1188 return addStmt(C->getCond()); 1189} 1190 1191 1192CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1193 addLocalScopeAndDtors(C); 1194 CFGBlock* LastBlock = Block; 1195 1196 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1197 I != E; ++I ) { 1198 // If we hit a segment of code just containing ';' (NullStmts), we can 1199 // get a null block back. In such cases, just use the LastBlock 1200 if (CFGBlock *newBlock = addStmt(*I)) 1201 LastBlock = newBlock; 1202 1203 if (badCFG) 1204 return NULL; 1205 } 1206 1207 return LastBlock; 1208} 1209 1210CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1211 AddStmtChoice asc) { 1212 // Create the confluence block that will "merge" the results of the ternary 1213 // expression. 1214 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1215 AppendStmt(ConfluenceBlock, C, asc); 1216 if (badCFG) 1217 return 0; 1218 1219 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1220 1221 // Create a block for the LHS expression if there is an LHS expression. A 1222 // GCC extension allows LHS to be NULL, causing the condition to be the 1223 // value that is returned instead. 1224 // e.g: x ?: y is shorthand for: x ? x : y; 1225 Succ = ConfluenceBlock; 1226 Block = NULL; 1227 CFGBlock* LHSBlock = NULL; 1228 if (C->getLHS()) { 1229 LHSBlock = Visit(C->getLHS(), alwaysAdd); 1230 if (badCFG) 1231 return 0; 1232 Block = NULL; 1233 } 1234 1235 // Create the block for the RHS expression. 1236 Succ = ConfluenceBlock; 1237 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1238 if (badCFG) 1239 return 0; 1240 1241 // Create the block that will contain the condition. 1242 Block = createBlock(false); 1243 1244 // See if this is a known constant. 1245 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1246 if (LHSBlock) { 1247 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1248 } else { 1249 if (KnownVal.isFalse()) { 1250 // If we know the condition is false, add NULL as the successor for 1251 // the block containing the condition. In this case, the confluence 1252 // block will have just one predecessor. 1253 AddSuccessor(Block, 0); 1254 assert(ConfluenceBlock->pred_size() == 1); 1255 } else { 1256 // If we have no LHS expression, add the ConfluenceBlock as a direct 1257 // successor for the block containing the condition. Moreover, we need to 1258 // reverse the order of the predecessors in the ConfluenceBlock because 1259 // the RHSBlock will have been added to the succcessors already, and we 1260 // want the first predecessor to the the block containing the expression 1261 // for the case when the ternary expression evaluates to true. 1262 AddSuccessor(Block, ConfluenceBlock); 1263 // Note that there can possibly only be one predecessor if one of the 1264 // subexpressions resulted in calling a noreturn function. 1265 std::reverse(ConfluenceBlock->pred_begin(), 1266 ConfluenceBlock->pred_end()); 1267 } 1268 } 1269 1270 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1271 Block->setTerminator(C); 1272 return addStmt(C->getCond()); 1273} 1274 1275CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1276 if (DS->isSingleDecl()) 1277 return VisitDeclSubExpr(DS); 1278 1279 CFGBlock *B = 0; 1280 1281 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1282 typedef llvm::SmallVector<Decl*,10> BufTy; 1283 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1284 1285 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1286 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1287 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1288 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1289 1290 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1291 // automatically freed with the CFG. 1292 DeclGroupRef DG(*I); 1293 Decl *D = *I; 1294 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1295 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1296 1297 // Append the fake DeclStmt to block. 1298 B = VisitDeclSubExpr(DSNew); 1299 } 1300 1301 return B; 1302} 1303 1304/// VisitDeclSubExpr - Utility method to add block-level expressions for 1305/// DeclStmts and initializers in them. 1306CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1307 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1308 1309 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1310 1311 if (!VD) { 1312 autoCreateBlock(); 1313 AppendStmt(Block, DS); 1314 return Block; 1315 } 1316 1317 bool IsReference = false; 1318 bool HasTemporaries = false; 1319 1320 // Destructors of temporaries in initialization expression should be called 1321 // after initialization finishes. 1322 Expr *Init = VD->getInit(); 1323 if (Init) { 1324 IsReference = VD->getType()->isReferenceType(); 1325 HasTemporaries = isa<CXXExprWithTemporaries>(Init); 1326 1327 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1328 // Generate destructors for temporaries in initialization expression. 1329 VisitForTemporaryDtors(cast<CXXExprWithTemporaries>(Init)->getSubExpr(), 1330 IsReference); 1331 } 1332 } 1333 1334 autoCreateBlock(); 1335 AppendStmt(Block, DS); 1336 1337 if (Init) { 1338 AddStmtChoice asc = AddStmtChoice().withAsLValue(IsReference); 1339 if (HasTemporaries) 1340 // For expression with temporaries go directly to subexpression to omit 1341 // generating destructors for the second time. 1342 Visit(cast<CXXExprWithTemporaries>(Init)->getSubExpr(), asc); 1343 else 1344 Visit(Init, asc); 1345 } 1346 1347 // If the type of VD is a VLA, then we must process its size expressions. 1348 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1349 VA = FindVA(VA->getElementType().getTypePtr())) 1350 Block = addStmt(VA->getSizeExpr()); 1351 1352 // Remove variable from local scope. 1353 if (ScopePos && VD == *ScopePos) 1354 ++ScopePos; 1355 1356 return Block; 1357} 1358 1359CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1360 // We may see an if statement in the middle of a basic block, or it may be the 1361 // first statement we are processing. In either case, we create a new basic 1362 // block. First, we create the blocks for the then...else statements, and 1363 // then we create the block containing the if statement. If we were in the 1364 // middle of a block, we stop processing that block. That block is then the 1365 // implicit successor for the "then" and "else" clauses. 1366 1367 // Save local scope position because in case of condition variable ScopePos 1368 // won't be restored when traversing AST. 1369 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1370 1371 // Create local scope for possible condition variable. 1372 // Store scope position. Add implicit destructor. 1373 if (VarDecl* VD = I->getConditionVariable()) { 1374 LocalScope::const_iterator BeginScopePos = ScopePos; 1375 addLocalScopeForVarDecl(VD); 1376 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1377 } 1378 1379 // The block we were proccessing is now finished. Make it the successor 1380 // block. 1381 if (Block) { 1382 Succ = Block; 1383 if (badCFG) 1384 return 0; 1385 } 1386 1387 // Process the false branch. 1388 CFGBlock* ElseBlock = Succ; 1389 1390 if (Stmt* Else = I->getElse()) { 1391 SaveAndRestore<CFGBlock*> sv(Succ); 1392 1393 // NULL out Block so that the recursive call to Visit will 1394 // create a new basic block. 1395 Block = NULL; 1396 1397 // If branch is not a compound statement create implicit scope 1398 // and add destructors. 1399 if (!isa<CompoundStmt>(Else)) 1400 addLocalScopeAndDtors(Else); 1401 1402 ElseBlock = addStmt(Else); 1403 1404 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1405 ElseBlock = sv.get(); 1406 else if (Block) { 1407 if (badCFG) 1408 return 0; 1409 } 1410 } 1411 1412 // Process the true branch. 1413 CFGBlock* ThenBlock; 1414 { 1415 Stmt* Then = I->getThen(); 1416 assert(Then); 1417 SaveAndRestore<CFGBlock*> sv(Succ); 1418 Block = NULL; 1419 1420 // If branch is not a compound statement create implicit scope 1421 // and add destructors. 1422 if (!isa<CompoundStmt>(Then)) 1423 addLocalScopeAndDtors(Then); 1424 1425 ThenBlock = addStmt(Then); 1426 1427 if (!ThenBlock) { 1428 // We can reach here if the "then" body has all NullStmts. 1429 // Create an empty block so we can distinguish between true and false 1430 // branches in path-sensitive analyses. 1431 ThenBlock = createBlock(false); 1432 AddSuccessor(ThenBlock, sv.get()); 1433 } else if (Block) { 1434 if (badCFG) 1435 return 0; 1436 } 1437 } 1438 1439 // Now create a new block containing the if statement. 1440 Block = createBlock(false); 1441 1442 // Set the terminator of the new block to the If statement. 1443 Block->setTerminator(I); 1444 1445 // See if this is a known constant. 1446 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1447 1448 // Now add the successors. 1449 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1450 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1451 1452 // Add the condition as the last statement in the new block. This may create 1453 // new blocks as the condition may contain control-flow. Any newly created 1454 // blocks will be pointed to be "Block". 1455 Block = addStmt(I->getCond()); 1456 1457 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1458 // and the condition variable initialization to the CFG. 1459 if (VarDecl *VD = I->getConditionVariable()) { 1460 if (Expr *Init = VD->getInit()) { 1461 autoCreateBlock(); 1462 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1463 addStmt(Init); 1464 } 1465 } 1466 1467 return Block; 1468} 1469 1470 1471CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1472 // If we were in the middle of a block we stop processing that block. 1473 // 1474 // NOTE: If a "return" appears in the middle of a block, this means that the 1475 // code afterwards is DEAD (unreachable). We still keep a basic block 1476 // for that code; a simple "mark-and-sweep" from the entry block will be 1477 // able to report such dead blocks. 1478 1479 // Create the new block. 1480 Block = createBlock(false); 1481 1482 // The Exit block is the only successor. 1483 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1484 AddSuccessor(Block, &cfg->getExit()); 1485 1486 // Add the return statement to the block. This may create new blocks if R 1487 // contains control-flow (short-circuit operations). 1488 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1489} 1490 1491CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1492 // Get the block of the labeled statement. Add it to our map. 1493 addStmt(L->getSubStmt()); 1494 CFGBlock* LabelBlock = Block; 1495 1496 if (!LabelBlock) // This can happen when the body is empty, i.e. 1497 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1498 1499 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1500 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1501 1502 // Labels partition blocks, so this is the end of the basic block we were 1503 // processing (L is the block's label). Because this is label (and we have 1504 // already processed the substatement) there is no extra control-flow to worry 1505 // about. 1506 LabelBlock->setLabel(L); 1507 if (badCFG) 1508 return 0; 1509 1510 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1511 Block = NULL; 1512 1513 // This block is now the implicit successor of other blocks. 1514 Succ = LabelBlock; 1515 1516 return LabelBlock; 1517} 1518 1519CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1520 // Goto is a control-flow statement. Thus we stop processing the current 1521 // block and create a new one. 1522 1523 Block = createBlock(false); 1524 Block->setTerminator(G); 1525 1526 // If we already know the mapping to the label block add the successor now. 1527 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1528 1529 if (I == LabelMap.end()) 1530 // We will need to backpatch this block later. 1531 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1532 else { 1533 JumpTarget JT = I->second; 1534 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1535 AddSuccessor(Block, JT.Block); 1536 } 1537 1538 return Block; 1539} 1540 1541CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1542 CFGBlock* LoopSuccessor = NULL; 1543 1544 // Save local scope position because in case of condition variable ScopePos 1545 // won't be restored when traversing AST. 1546 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1547 1548 // Create local scope for init statement and possible condition variable. 1549 // Add destructor for init statement and condition variable. 1550 // Store scope position for continue statement. 1551 if (Stmt* Init = F->getInit()) 1552 addLocalScopeForStmt(Init); 1553 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1554 1555 if (VarDecl* VD = F->getConditionVariable()) 1556 addLocalScopeForVarDecl(VD); 1557 LocalScope::const_iterator ContinueScopePos = ScopePos; 1558 1559 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1560 1561 // "for" is a control-flow statement. Thus we stop processing the current 1562 // block. 1563 if (Block) { 1564 if (badCFG) 1565 return 0; 1566 LoopSuccessor = Block; 1567 } else 1568 LoopSuccessor = Succ; 1569 1570 // Save the current value for the break targets. 1571 // All breaks should go to the code following the loop. 1572 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1573 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1574 1575 // Because of short-circuit evaluation, the condition of the loop can span 1576 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1577 // evaluate the condition. 1578 CFGBlock* ExitConditionBlock = createBlock(false); 1579 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1580 1581 // Set the terminator for the "exit" condition block. 1582 ExitConditionBlock->setTerminator(F); 1583 1584 // Now add the actual condition to the condition block. Because the condition 1585 // itself may contain control-flow, new blocks may be created. 1586 if (Stmt* C = F->getCond()) { 1587 Block = ExitConditionBlock; 1588 EntryConditionBlock = addStmt(C); 1589 assert(Block == EntryConditionBlock || 1590 (Block == 0 && EntryConditionBlock == Succ)); 1591 1592 // If this block contains a condition variable, add both the condition 1593 // variable and initializer to the CFG. 1594 if (VarDecl *VD = F->getConditionVariable()) { 1595 if (Expr *Init = VD->getInit()) { 1596 autoCreateBlock(); 1597 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1598 EntryConditionBlock = addStmt(Init); 1599 assert(Block == EntryConditionBlock); 1600 } 1601 } 1602 1603 if (Block) { 1604 if (badCFG) 1605 return 0; 1606 } 1607 } 1608 1609 // The condition block is the implicit successor for the loop body as well as 1610 // any code above the loop. 1611 Succ = EntryConditionBlock; 1612 1613 // See if this is a known constant. 1614 TryResult KnownVal(true); 1615 1616 if (F->getCond()) 1617 KnownVal = TryEvaluateBool(F->getCond()); 1618 1619 // Now create the loop body. 1620 { 1621 assert(F->getBody()); 1622 1623 // Save the current values for Block, Succ, and continue targets. 1624 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1625 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1626 1627 // Create a new block to contain the (bottom) of the loop body. 1628 Block = NULL; 1629 1630 // Loop body should end with destructor of Condition variable (if any). 1631 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1632 1633 if (Stmt* I = F->getInc()) { 1634 // Generate increment code in its own basic block. This is the target of 1635 // continue statements. 1636 Succ = addStmt(I); 1637 } else { 1638 // No increment code. Create a special, empty, block that is used as the 1639 // target block for "looping back" to the start of the loop. 1640 assert(Succ == EntryConditionBlock); 1641 Succ = Block ? Block : createBlock(); 1642 } 1643 1644 // Finish up the increment (or empty) block if it hasn't been already. 1645 if (Block) { 1646 assert(Block == Succ); 1647 if (badCFG) 1648 return 0; 1649 Block = 0; 1650 } 1651 1652 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1653 1654 // The starting block for the loop increment is the block that should 1655 // represent the 'loop target' for looping back to the start of the loop. 1656 ContinueJumpTarget.Block->setLoopTarget(F); 1657 1658 // If body is not a compound statement create implicit scope 1659 // and add destructors. 1660 if (!isa<CompoundStmt>(F->getBody())) 1661 addLocalScopeAndDtors(F->getBody()); 1662 1663 // Now populate the body block, and in the process create new blocks as we 1664 // walk the body of the loop. 1665 CFGBlock* BodyBlock = addStmt(F->getBody()); 1666 1667 if (!BodyBlock) 1668 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1669 else if (badCFG) 1670 return 0; 1671 1672 // This new body block is a successor to our "exit" condition block. 1673 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1674 } 1675 1676 // Link up the condition block with the code that follows the loop. (the 1677 // false branch). 1678 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1679 1680 // If the loop contains initialization, create a new block for those 1681 // statements. This block can also contain statements that precede the loop. 1682 if (Stmt* I = F->getInit()) { 1683 Block = createBlock(); 1684 return addStmt(I); 1685 } 1686 1687 // There is no loop initialization. We are thus basically a while loop. 1688 // NULL out Block to force lazy block construction. 1689 Block = NULL; 1690 Succ = EntryConditionBlock; 1691 return EntryConditionBlock; 1692} 1693 1694CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1695 if (asc.alwaysAdd()) { 1696 autoCreateBlock(); 1697 AppendStmt(Block, M, asc); 1698 } 1699 return Visit(M->getBase(), 1700 AddStmtChoice().withAsLValue(!M->isArrow())); 1701} 1702 1703CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1704 // Objective-C fast enumeration 'for' statements: 1705 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1706 // 1707 // for ( Type newVariable in collection_expression ) { statements } 1708 // 1709 // becomes: 1710 // 1711 // prologue: 1712 // 1. collection_expression 1713 // T. jump to loop_entry 1714 // loop_entry: 1715 // 1. side-effects of element expression 1716 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1717 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1718 // TB: 1719 // statements 1720 // T. jump to loop_entry 1721 // FB: 1722 // what comes after 1723 // 1724 // and 1725 // 1726 // Type existingItem; 1727 // for ( existingItem in expression ) { statements } 1728 // 1729 // becomes: 1730 // 1731 // the same with newVariable replaced with existingItem; the binding works 1732 // the same except that for one ObjCForCollectionStmt::getElement() returns 1733 // a DeclStmt and the other returns a DeclRefExpr. 1734 // 1735 1736 CFGBlock* LoopSuccessor = 0; 1737 1738 if (Block) { 1739 if (badCFG) 1740 return 0; 1741 LoopSuccessor = Block; 1742 Block = 0; 1743 } else 1744 LoopSuccessor = Succ; 1745 1746 // Build the condition blocks. 1747 CFGBlock* ExitConditionBlock = createBlock(false); 1748 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1749 1750 // Set the terminator for the "exit" condition block. 1751 ExitConditionBlock->setTerminator(S); 1752 1753 // The last statement in the block should be the ObjCForCollectionStmt, which 1754 // performs the actual binding to 'element' and determines if there are any 1755 // more items in the collection. 1756 AppendStmt(ExitConditionBlock, S); 1757 Block = ExitConditionBlock; 1758 1759 // Walk the 'element' expression to see if there are any side-effects. We 1760 // generate new blocks as necesary. We DON'T add the statement by default to 1761 // the CFG unless it contains control-flow. 1762 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1763 if (Block) { 1764 if (badCFG) 1765 return 0; 1766 Block = 0; 1767 } 1768 1769 // The condition block is the implicit successor for the loop body as well as 1770 // any code above the loop. 1771 Succ = EntryConditionBlock; 1772 1773 // Now create the true branch. 1774 { 1775 // Save the current values for Succ, continue and break targets. 1776 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1777 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1778 save_break(BreakJumpTarget); 1779 1780 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1781 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1782 1783 CFGBlock* BodyBlock = addStmt(S->getBody()); 1784 1785 if (!BodyBlock) 1786 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1787 else if (Block) { 1788 if (badCFG) 1789 return 0; 1790 } 1791 1792 // This new body block is a successor to our "exit" condition block. 1793 AddSuccessor(ExitConditionBlock, BodyBlock); 1794 } 1795 1796 // Link up the condition block with the code that follows the loop. 1797 // (the false branch). 1798 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1799 1800 // Now create a prologue block to contain the collection expression. 1801 Block = createBlock(); 1802 return addStmt(S->getCollection()); 1803} 1804 1805CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1806 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1807 1808 // Inline the body. 1809 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1810 1811 // The sync body starts its own basic block. This makes it a little easier 1812 // for diagnostic clients. 1813 if (SyncBlock) { 1814 if (badCFG) 1815 return 0; 1816 1817 Block = 0; 1818 Succ = SyncBlock; 1819 } 1820 1821 // Add the @synchronized to the CFG. 1822 autoCreateBlock(); 1823 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1824 1825 // Inline the sync expression. 1826 return addStmt(S->getSynchExpr()); 1827} 1828 1829CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1830 // FIXME 1831 return NYS(); 1832} 1833 1834CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1835 CFGBlock* LoopSuccessor = NULL; 1836 1837 // Save local scope position because in case of condition variable ScopePos 1838 // won't be restored when traversing AST. 1839 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1840 1841 // Create local scope for possible condition variable. 1842 // Store scope position for continue statement. 1843 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1844 if (VarDecl* VD = W->getConditionVariable()) { 1845 addLocalScopeForVarDecl(VD); 1846 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1847 } 1848 1849 // "while" is a control-flow statement. Thus we stop processing the current 1850 // block. 1851 if (Block) { 1852 if (badCFG) 1853 return 0; 1854 LoopSuccessor = Block; 1855 } else 1856 LoopSuccessor = Succ; 1857 1858 // Because of short-circuit evaluation, the condition of the loop can span 1859 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1860 // evaluate the condition. 1861 CFGBlock* ExitConditionBlock = createBlock(false); 1862 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1863 1864 // Set the terminator for the "exit" condition block. 1865 ExitConditionBlock->setTerminator(W); 1866 1867 // Now add the actual condition to the condition block. Because the condition 1868 // itself may contain control-flow, new blocks may be created. Thus we update 1869 // "Succ" after adding the condition. 1870 if (Stmt* C = W->getCond()) { 1871 Block = ExitConditionBlock; 1872 EntryConditionBlock = addStmt(C); 1873 // The condition might finish the current 'Block'. 1874 Block = EntryConditionBlock; 1875 1876 // If this block contains a condition variable, add both the condition 1877 // variable and initializer to the CFG. 1878 if (VarDecl *VD = W->getConditionVariable()) { 1879 if (Expr *Init = VD->getInit()) { 1880 autoCreateBlock(); 1881 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1882 EntryConditionBlock = addStmt(Init); 1883 assert(Block == EntryConditionBlock); 1884 } 1885 } 1886 1887 if (Block) { 1888 if (badCFG) 1889 return 0; 1890 } 1891 } 1892 1893 // The condition block is the implicit successor for the loop body as well as 1894 // any code above the loop. 1895 Succ = EntryConditionBlock; 1896 1897 // See if this is a known constant. 1898 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1899 1900 // Process the loop body. 1901 { 1902 assert(W->getBody()); 1903 1904 // Save the current values for Block, Succ, and continue and break targets 1905 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1906 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1907 save_break(BreakJumpTarget); 1908 1909 // Create an empty block to represent the transition block for looping back 1910 // to the head of the loop. 1911 Block = 0; 1912 assert(Succ == EntryConditionBlock); 1913 Succ = createBlock(); 1914 Succ->setLoopTarget(W); 1915 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1916 1917 // All breaks should go to the code following the loop. 1918 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1919 1920 // NULL out Block to force lazy instantiation of blocks for the body. 1921 Block = NULL; 1922 1923 // Loop body should end with destructor of Condition variable (if any). 1924 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1925 1926 // If body is not a compound statement create implicit scope 1927 // and add destructors. 1928 if (!isa<CompoundStmt>(W->getBody())) 1929 addLocalScopeAndDtors(W->getBody()); 1930 1931 // Create the body. The returned block is the entry to the loop body. 1932 CFGBlock* BodyBlock = addStmt(W->getBody()); 1933 1934 if (!BodyBlock) 1935 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1936 else if (Block) { 1937 if (badCFG) 1938 return 0; 1939 } 1940 1941 // Add the loop body entry as a successor to the condition. 1942 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1943 } 1944 1945 // Link up the condition block with the code that follows the loop. (the 1946 // false branch). 1947 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1948 1949 // There can be no more statements in the condition block since we loop back 1950 // to this block. NULL out Block to force lazy creation of another block. 1951 Block = NULL; 1952 1953 // Return the condition block, which is the dominating block for the loop. 1954 Succ = EntryConditionBlock; 1955 return EntryConditionBlock; 1956} 1957 1958 1959CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1960 // FIXME: For now we pretend that @catch and the code it contains does not 1961 // exit. 1962 return Block; 1963} 1964 1965CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1966 // FIXME: This isn't complete. We basically treat @throw like a return 1967 // statement. 1968 1969 // If we were in the middle of a block we stop processing that block. 1970 if (badCFG) 1971 return 0; 1972 1973 // Create the new block. 1974 Block = createBlock(false); 1975 1976 // The Exit block is the only successor. 1977 AddSuccessor(Block, &cfg->getExit()); 1978 1979 // Add the statement to the block. This may create new blocks if S contains 1980 // control-flow (short-circuit operations). 1981 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1982} 1983 1984CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1985 // If we were in the middle of a block we stop processing that block. 1986 if (badCFG) 1987 return 0; 1988 1989 // Create the new block. 1990 Block = createBlock(false); 1991 1992 if (TryTerminatedBlock) 1993 // The current try statement is the only successor. 1994 AddSuccessor(Block, TryTerminatedBlock); 1995 else 1996 // otherwise the Exit block is the only successor. 1997 AddSuccessor(Block, &cfg->getExit()); 1998 1999 // Add the statement to the block. This may create new blocks if S contains 2000 // control-flow (short-circuit operations). 2001 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2002} 2003 2004CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 2005 CFGBlock* LoopSuccessor = NULL; 2006 2007 // "do...while" is a control-flow statement. Thus we stop processing the 2008 // current block. 2009 if (Block) { 2010 if (badCFG) 2011 return 0; 2012 LoopSuccessor = Block; 2013 } else 2014 LoopSuccessor = Succ; 2015 2016 // Because of short-circuit evaluation, the condition of the loop can span 2017 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2018 // evaluate the condition. 2019 CFGBlock* ExitConditionBlock = createBlock(false); 2020 CFGBlock* EntryConditionBlock = ExitConditionBlock; 2021 2022 // Set the terminator for the "exit" condition block. 2023 ExitConditionBlock->setTerminator(D); 2024 2025 // Now add the actual condition to the condition block. Because the condition 2026 // itself may contain control-flow, new blocks may be created. 2027 if (Stmt* C = D->getCond()) { 2028 Block = ExitConditionBlock; 2029 EntryConditionBlock = addStmt(C); 2030 if (Block) { 2031 if (badCFG) 2032 return 0; 2033 } 2034 } 2035 2036 // The condition block is the implicit successor for the loop body. 2037 Succ = EntryConditionBlock; 2038 2039 // See if this is a known constant. 2040 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 2041 2042 // Process the loop body. 2043 CFGBlock* BodyBlock = NULL; 2044 { 2045 assert(D->getBody()); 2046 2047 // Save the current values for Block, Succ, and continue and break targets 2048 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2049 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2050 save_break(BreakJumpTarget); 2051 2052 // All continues within this loop should go to the condition block 2053 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2054 2055 // All breaks should go to the code following the loop. 2056 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2057 2058 // NULL out Block to force lazy instantiation of blocks for the body. 2059 Block = NULL; 2060 2061 // If body is not a compound statement create implicit scope 2062 // and add destructors. 2063 if (!isa<CompoundStmt>(D->getBody())) 2064 addLocalScopeAndDtors(D->getBody()); 2065 2066 // Create the body. The returned block is the entry to the loop body. 2067 BodyBlock = addStmt(D->getBody()); 2068 2069 if (!BodyBlock) 2070 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2071 else if (Block) { 2072 if (badCFG) 2073 return 0; 2074 } 2075 2076 if (!KnownVal.isFalse()) { 2077 // Add an intermediate block between the BodyBlock and the 2078 // ExitConditionBlock to represent the "loop back" transition. Create an 2079 // empty block to represent the transition block for looping back to the 2080 // head of the loop. 2081 // FIXME: Can we do this more efficiently without adding another block? 2082 Block = NULL; 2083 Succ = BodyBlock; 2084 CFGBlock *LoopBackBlock = createBlock(); 2085 LoopBackBlock->setLoopTarget(D); 2086 2087 // Add the loop body entry as a successor to the condition. 2088 AddSuccessor(ExitConditionBlock, LoopBackBlock); 2089 } 2090 else 2091 AddSuccessor(ExitConditionBlock, NULL); 2092 } 2093 2094 // Link up the condition block with the code that follows the loop. 2095 // (the false branch). 2096 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2097 2098 // There can be no more statements in the body block(s) since we loop back to 2099 // the body. NULL out Block to force lazy creation of another block. 2100 Block = NULL; 2101 2102 // Return the loop body, which is the dominating block for the loop. 2103 Succ = BodyBlock; 2104 return BodyBlock; 2105} 2106 2107CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2108 // "continue" is a control-flow statement. Thus we stop processing the 2109 // current block. 2110 if (badCFG) 2111 return 0; 2112 2113 // Now create a new block that ends with the continue statement. 2114 Block = createBlock(false); 2115 Block->setTerminator(C); 2116 2117 // If there is no target for the continue, then we are looking at an 2118 // incomplete AST. This means the CFG cannot be constructed. 2119 if (ContinueJumpTarget.Block) { 2120 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 2121 AddSuccessor(Block, ContinueJumpTarget.Block); 2122 } else 2123 badCFG = true; 2124 2125 return Block; 2126} 2127 2128CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 2129 AddStmtChoice asc) { 2130 2131 if (asc.alwaysAdd()) { 2132 autoCreateBlock(); 2133 AppendStmt(Block, E); 2134 } 2135 2136 // VLA types have expressions that must be evaluated. 2137 if (E->isArgumentType()) { 2138 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 2139 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2140 addStmt(VA->getSizeExpr()); 2141 } 2142 2143 return Block; 2144} 2145 2146/// VisitStmtExpr - Utility method to handle (nested) statement 2147/// expressions (a GCC extension). 2148CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2149 if (asc.alwaysAdd()) { 2150 autoCreateBlock(); 2151 AppendStmt(Block, SE); 2152 } 2153 return VisitCompoundStmt(SE->getSubStmt()); 2154} 2155 2156CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2157 // "switch" is a control-flow statement. Thus we stop processing the current 2158 // block. 2159 CFGBlock* SwitchSuccessor = NULL; 2160 2161 // Save local scope position because in case of condition variable ScopePos 2162 // won't be restored when traversing AST. 2163 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2164 2165 // Create local scope for possible condition variable. 2166 // Store scope position. Add implicit destructor. 2167 if (VarDecl* VD = Terminator->getConditionVariable()) { 2168 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2169 addLocalScopeForVarDecl(VD); 2170 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2171 } 2172 2173 if (Block) { 2174 if (badCFG) 2175 return 0; 2176 SwitchSuccessor = Block; 2177 } else SwitchSuccessor = Succ; 2178 2179 // Save the current "switch" context. 2180 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2181 save_default(DefaultCaseBlock); 2182 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2183 2184 // Set the "default" case to be the block after the switch statement. If the 2185 // switch statement contains a "default:", this value will be overwritten with 2186 // the block for that code. 2187 DefaultCaseBlock = SwitchSuccessor; 2188 2189 // Create a new block that will contain the switch statement. 2190 SwitchTerminatedBlock = createBlock(false); 2191 2192 // Now process the switch body. The code after the switch is the implicit 2193 // successor. 2194 Succ = SwitchSuccessor; 2195 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2196 2197 // When visiting the body, the case statements should automatically get linked 2198 // up to the switch. We also don't keep a pointer to the body, since all 2199 // control-flow from the switch goes to case/default statements. 2200 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2201 Block = NULL; 2202 2203 // If body is not a compound statement create implicit scope 2204 // and add destructors. 2205 if (!isa<CompoundStmt>(Terminator->getBody())) 2206 addLocalScopeAndDtors(Terminator->getBody()); 2207 2208 addStmt(Terminator->getBody()); 2209 if (Block) { 2210 if (badCFG) 2211 return 0; 2212 } 2213 2214 // If we have no "default:" case, the default transition is to the code 2215 // following the switch body. 2216 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2217 2218 // Add the terminator and condition in the switch block. 2219 SwitchTerminatedBlock->setTerminator(Terminator); 2220 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2221 Block = SwitchTerminatedBlock; 2222 Block = addStmt(Terminator->getCond()); 2223 2224 // Finally, if the SwitchStmt contains a condition variable, add both the 2225 // SwitchStmt and the condition variable initialization to the CFG. 2226 if (VarDecl *VD = Terminator->getConditionVariable()) { 2227 if (Expr *Init = VD->getInit()) { 2228 autoCreateBlock(); 2229 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2230 addStmt(Init); 2231 } 2232 } 2233 2234 return Block; 2235} 2236 2237CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2238 // CaseStmts are essentially labels, so they are the first statement in a 2239 // block. 2240 CFGBlock *TopBlock = 0, *LastBlock = 0; 2241 2242 if (Stmt *Sub = CS->getSubStmt()) { 2243 // For deeply nested chains of CaseStmts, instead of doing a recursion 2244 // (which can blow out the stack), manually unroll and create blocks 2245 // along the way. 2246 while (isa<CaseStmt>(Sub)) { 2247 CFGBlock *CurrentBlock = createBlock(false); 2248 CurrentBlock->setLabel(CS); 2249 2250 if (TopBlock) 2251 AddSuccessor(LastBlock, CurrentBlock); 2252 else 2253 TopBlock = CurrentBlock; 2254 2255 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2256 LastBlock = CurrentBlock; 2257 2258 CS = cast<CaseStmt>(Sub); 2259 Sub = CS->getSubStmt(); 2260 } 2261 2262 addStmt(Sub); 2263 } 2264 2265 CFGBlock* CaseBlock = Block; 2266 if (!CaseBlock) 2267 CaseBlock = createBlock(); 2268 2269 // Cases statements partition blocks, so this is the top of the basic block we 2270 // were processing (the "case XXX:" is the label). 2271 CaseBlock->setLabel(CS); 2272 2273 if (badCFG) 2274 return 0; 2275 2276 // Add this block to the list of successors for the block with the switch 2277 // statement. 2278 assert(SwitchTerminatedBlock); 2279 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2280 2281 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2282 Block = NULL; 2283 2284 if (TopBlock) { 2285 AddSuccessor(LastBlock, CaseBlock); 2286 Succ = TopBlock; 2287 } else { 2288 // This block is now the implicit successor of other blocks. 2289 Succ = CaseBlock; 2290 } 2291 2292 return Succ; 2293} 2294 2295CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2296 if (Terminator->getSubStmt()) 2297 addStmt(Terminator->getSubStmt()); 2298 2299 DefaultCaseBlock = Block; 2300 2301 if (!DefaultCaseBlock) 2302 DefaultCaseBlock = createBlock(); 2303 2304 // Default statements partition blocks, so this is the top of the basic block 2305 // we were processing (the "default:" is the label). 2306 DefaultCaseBlock->setLabel(Terminator); 2307 2308 if (badCFG) 2309 return 0; 2310 2311 // Unlike case statements, we don't add the default block to the successors 2312 // for the switch statement immediately. This is done when we finish 2313 // processing the switch statement. This allows for the default case 2314 // (including a fall-through to the code after the switch statement) to always 2315 // be the last successor of a switch-terminated block. 2316 2317 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2318 Block = NULL; 2319 2320 // This block is now the implicit successor of other blocks. 2321 Succ = DefaultCaseBlock; 2322 2323 return DefaultCaseBlock; 2324} 2325 2326CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2327 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2328 // current block. 2329 CFGBlock* TrySuccessor = NULL; 2330 2331 if (Block) { 2332 if (badCFG) 2333 return 0; 2334 TrySuccessor = Block; 2335 } else TrySuccessor = Succ; 2336 2337 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2338 2339 // Create a new block that will contain the try statement. 2340 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2341 // Add the terminator in the try block. 2342 NewTryTerminatedBlock->setTerminator(Terminator); 2343 2344 bool HasCatchAll = false; 2345 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2346 // The code after the try is the implicit successor. 2347 Succ = TrySuccessor; 2348 CXXCatchStmt *CS = Terminator->getHandler(h); 2349 if (CS->getExceptionDecl() == 0) { 2350 HasCatchAll = true; 2351 } 2352 Block = NULL; 2353 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2354 if (CatchBlock == 0) 2355 return 0; 2356 // Add this block to the list of successors for the block with the try 2357 // statement. 2358 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2359 } 2360 if (!HasCatchAll) { 2361 if (PrevTryTerminatedBlock) 2362 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2363 else 2364 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2365 } 2366 2367 // The code after the try is the implicit successor. 2368 Succ = TrySuccessor; 2369 2370 // Save the current "try" context. 2371 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2372 TryTerminatedBlock = NewTryTerminatedBlock; 2373 2374 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2375 Block = NULL; 2376 Block = addStmt(Terminator->getTryBlock()); 2377 return Block; 2378} 2379 2380CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2381 // CXXCatchStmt are treated like labels, so they are the first statement in a 2382 // block. 2383 2384 // Save local scope position because in case of exception variable ScopePos 2385 // won't be restored when traversing AST. 2386 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2387 2388 // Create local scope for possible exception variable. 2389 // Store scope position. Add implicit destructor. 2390 if (VarDecl* VD = CS->getExceptionDecl()) { 2391 LocalScope::const_iterator BeginScopePos = ScopePos; 2392 addLocalScopeForVarDecl(VD); 2393 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2394 } 2395 2396 if (CS->getHandlerBlock()) 2397 addStmt(CS->getHandlerBlock()); 2398 2399 CFGBlock* CatchBlock = Block; 2400 if (!CatchBlock) 2401 CatchBlock = createBlock(); 2402 2403 CatchBlock->setLabel(CS); 2404 2405 if (badCFG) 2406 return 0; 2407 2408 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2409 Block = NULL; 2410 2411 return CatchBlock; 2412} 2413 2414CFGBlock *CFGBuilder::VisitCXXExprWithTemporaries(CXXExprWithTemporaries *E, 2415 AddStmtChoice asc) { 2416 if (BuildOpts.AddImplicitDtors) { 2417 // If adding implicit destructors visit the full expression for adding 2418 // destructors of temporaries. 2419 VisitForTemporaryDtors(E->getSubExpr()); 2420 2421 // Full expression has to be added as CFGStmt so it will be sequenced 2422 // before destructors of it's temporaries. 2423 asc = asc.withAlwaysAdd(true); 2424 } 2425 return Visit(E->getSubExpr(), asc); 2426} 2427 2428CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2429 AddStmtChoice asc) { 2430 if (asc.alwaysAdd()) { 2431 autoCreateBlock(); 2432 AppendStmt(Block, E, asc); 2433 2434 // We do not want to propagate the AlwaysAdd property. 2435 asc = asc.withAlwaysAdd(false); 2436 } 2437 return Visit(E->getSubExpr(), asc); 2438} 2439 2440CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2441 AddStmtChoice asc) { 2442 autoCreateBlock(); 2443 if (!C->isElidable()) 2444 AppendStmt(Block, C, asc.withAlwaysAdd(true)); 2445 2446 return VisitChildren(C); 2447} 2448 2449CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2450 AddStmtChoice asc) { 2451 if (asc.alwaysAdd()) { 2452 autoCreateBlock(); 2453 AppendStmt(Block, E, asc); 2454 // We do not want to propagate the AlwaysAdd property. 2455 asc = asc.withAlwaysAdd(false); 2456 } 2457 return Visit(E->getSubExpr(), asc); 2458} 2459 2460CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2461 AddStmtChoice asc) { 2462 autoCreateBlock(); 2463 AppendStmt(Block, C, asc.withAlwaysAdd(true)); 2464 return VisitChildren(C); 2465} 2466 2467CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2468 AddStmtChoice asc) { 2469 autoCreateBlock(); 2470 AppendStmt(Block, C, asc.withAlwaysAdd(true)); 2471 return VisitChildren(C); 2472} 2473 2474CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2475 AddStmtChoice asc) { 2476 if (asc.alwaysAdd()) { 2477 autoCreateBlock(); 2478 AppendStmt(Block, E, asc); 2479 // We do not want to propagate the AlwaysAdd property. 2480 asc = asc.withAlwaysAdd(false); 2481 } 2482 return Visit(E->getSubExpr(), asc); 2483} 2484 2485CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2486 // Lazily create the indirect-goto dispatch block if there isn't one already. 2487 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2488 2489 if (!IBlock) { 2490 IBlock = createBlock(false); 2491 cfg->setIndirectGotoBlock(IBlock); 2492 } 2493 2494 // IndirectGoto is a control-flow statement. Thus we stop processing the 2495 // current block and create a new one. 2496 if (badCFG) 2497 return 0; 2498 2499 Block = createBlock(false); 2500 Block->setTerminator(I); 2501 AddSuccessor(Block, IBlock); 2502 return addStmt(I->getTarget()); 2503} 2504 2505CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2506tryAgain: 2507 if (!E) { 2508 badCFG = true; 2509 return NULL; 2510 } 2511 switch (E->getStmtClass()) { 2512 default: 2513 return VisitChildrenForTemporaryDtors(E); 2514 2515 case Stmt::BinaryOperatorClass: 2516 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2517 2518 case Stmt::CXXBindTemporaryExprClass: 2519 return VisitCXXBindTemporaryExprForTemporaryDtors( 2520 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2521 2522 case Stmt::ConditionalOperatorClass: 2523 return VisitConditionalOperatorForTemporaryDtors( 2524 cast<ConditionalOperator>(E), BindToTemporary); 2525 2526 case Stmt::ImplicitCastExprClass: 2527 // For implicit cast we want BindToTemporary to be passed further. 2528 E = cast<CastExpr>(E)->getSubExpr(); 2529 goto tryAgain; 2530 2531 case Stmt::ParenExprClass: 2532 E = cast<ParenExpr>(E)->getSubExpr(); 2533 goto tryAgain; 2534 } 2535} 2536 2537CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2538 // When visiting children for destructors we want to visit them in reverse 2539 // order. Because there's no reverse iterator for children must to reverse 2540 // them in helper vector. 2541 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2542 ChildrenVect ChildrenRev; 2543 for (Stmt::child_iterator I = E->child_begin(), L = E->child_end(); 2544 I != L; ++I) { 2545 if (*I) ChildrenRev.push_back(*I); 2546 } 2547 2548 CFGBlock *B = Block; 2549 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2550 L = ChildrenRev.rend(); I != L; ++I) { 2551 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2552 B = R; 2553 } 2554 return B; 2555} 2556 2557CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2558 if (E->isLogicalOp()) { 2559 // Destructors for temporaries in LHS expression should be called after 2560 // those for RHS expression. Even if this will unnecessarily create a block, 2561 // this block will be used at least by the full expression. 2562 autoCreateBlock(); 2563 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2564 if (badCFG) 2565 return NULL; 2566 2567 Succ = ConfluenceBlock; 2568 Block = NULL; 2569 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2570 2571 if (RHSBlock) { 2572 if (badCFG) 2573 return NULL; 2574 2575 // If RHS expression did produce destructors we need to connect created 2576 // blocks to CFG in same manner as for binary operator itself. 2577 CFGBlock *LHSBlock = createBlock(false); 2578 LHSBlock->setTerminator(CFGTerminator(E, true)); 2579 2580 // For binary operator LHS block is before RHS in list of predecessors 2581 // of ConfluenceBlock. 2582 std::reverse(ConfluenceBlock->pred_begin(), 2583 ConfluenceBlock->pred_end()); 2584 2585 // See if this is a known constant. 2586 TryResult KnownVal = TryEvaluateBool(E->getLHS()); 2587 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2588 KnownVal.negate(); 2589 2590 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2591 // itself. 2592 if (E->getOpcode() == BO_LOr) { 2593 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2594 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2595 } else { 2596 assert (E->getOpcode() == BO_LAnd); 2597 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2598 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2599 } 2600 2601 Block = LHSBlock; 2602 return LHSBlock; 2603 } 2604 2605 Block = ConfluenceBlock; 2606 return ConfluenceBlock; 2607 } 2608 2609 if (E->isAssignmentOp()) { 2610 // For assignment operator (=) LHS expression is visited 2611 // before RHS expression. For destructors visit them in reverse order. 2612 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2613 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2614 return LHSBlock ? LHSBlock : RHSBlock; 2615 } 2616 2617 // For any other binary operator RHS expression is visited before 2618 // LHS expression (order of children). For destructors visit them in reverse 2619 // order. 2620 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2621 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2622 return RHSBlock ? RHSBlock : LHSBlock; 2623} 2624 2625CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2626 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2627 // First add destructors for temporaries in subexpression. 2628 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2629 if (!BindToTemporary) { 2630 // If lifetime of temporary is not prolonged (by assigning to constant 2631 // reference) add destructor for it. 2632 autoCreateBlock(); 2633 appendTemporaryDtor(Block, E); 2634 B = Block; 2635 } 2636 return B; 2637} 2638 2639CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2640 ConditionalOperator *E, bool BindToTemporary) { 2641 // First add destructors for condition expression. Even if this will 2642 // unnecessarily create a block, this block will be used at least by the full 2643 // expression. 2644 autoCreateBlock(); 2645 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2646 if (badCFG) 2647 return NULL; 2648 2649 // Try to add block with destructors for LHS expression. 2650 CFGBlock *LHSBlock = NULL; 2651 if (E->getLHS()) { 2652 Succ = ConfluenceBlock; 2653 Block = NULL; 2654 LHSBlock = VisitForTemporaryDtors(E->getLHS(), BindToTemporary); 2655 if (badCFG) 2656 return NULL; 2657 } 2658 2659 // Try to add block with destructors for RHS expression; 2660 Succ = ConfluenceBlock; 2661 Block = NULL; 2662 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), BindToTemporary); 2663 if (badCFG) 2664 return NULL; 2665 2666 if (!RHSBlock && !LHSBlock) { 2667 // If neither LHS nor RHS expression had temporaries to destroy don't create 2668 // more blocks. 2669 Block = ConfluenceBlock; 2670 return Block; 2671 } 2672 2673 Block = createBlock(false); 2674 Block->setTerminator(CFGTerminator(E, true)); 2675 2676 // See if this is a known constant. 2677 const TryResult &KnownVal = TryEvaluateBool(E->getCond()); 2678 2679 if (LHSBlock) { 2680 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2681 } else if (KnownVal.isFalse()) { 2682 AddSuccessor(Block, NULL); 2683 } else { 2684 AddSuccessor(Block, ConfluenceBlock); 2685 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2686 } 2687 2688 if (!RHSBlock) 2689 RHSBlock = ConfluenceBlock; 2690 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2691 2692 return Block; 2693} 2694 2695} // end anonymous namespace 2696 2697/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2698/// no successors or predecessors. If this is the first block created in the 2699/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2700CFGBlock* CFG::createBlock() { 2701 bool first_block = begin() == end(); 2702 2703 // Create the block. 2704 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2705 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2706 Blocks.push_back(Mem, BlkBVC); 2707 2708 // If this is the first block, set it as the Entry and Exit. 2709 if (first_block) 2710 Entry = Exit = &back(); 2711 2712 // Return the block. 2713 return &back(); 2714} 2715 2716/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2717/// CFG is returned to the caller. 2718CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2719 BuildOptions BO) { 2720 CFGBuilder Builder; 2721 return Builder.buildCFG(D, Statement, C, BO); 2722} 2723 2724//===----------------------------------------------------------------------===// 2725// CFG: Queries for BlkExprs. 2726//===----------------------------------------------------------------------===// 2727 2728namespace { 2729 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2730} 2731 2732static void FindSubExprAssignments(Stmt *S, 2733 llvm::SmallPtrSet<Expr*,50>& Set) { 2734 if (!S) 2735 return; 2736 2737 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2738 Stmt *child = *I; 2739 if (!child) 2740 continue; 2741 2742 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2743 if (B->isAssignmentOp()) Set.insert(B); 2744 2745 FindSubExprAssignments(child, Set); 2746 } 2747} 2748 2749static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2750 BlkExprMapTy* M = new BlkExprMapTy(); 2751 2752 // Look for assignments that are used as subexpressions. These are the only 2753 // assignments that we want to *possibly* register as a block-level 2754 // expression. Basically, if an assignment occurs both in a subexpression and 2755 // at the block-level, it is a block-level expression. 2756 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2757 2758 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2759 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2760 if (CFGStmt S = BI->getAs<CFGStmt>()) 2761 FindSubExprAssignments(S, SubExprAssignments); 2762 2763 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2764 2765 // Iterate over the statements again on identify the Expr* and Stmt* at the 2766 // block-level that are block-level expressions. 2767 2768 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2769 CFGStmt CS = BI->getAs<CFGStmt>(); 2770 if (!CS.isValid()) 2771 continue; 2772 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2773 2774 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2775 // Assignment expressions that are not nested within another 2776 // expression are really "statements" whose value is never used by 2777 // another expression. 2778 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2779 continue; 2780 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2781 // Special handling for statement expressions. The last statement in 2782 // the statement expression is also a block-level expr. 2783 const CompoundStmt* C = Terminator->getSubStmt(); 2784 if (!C->body_empty()) { 2785 unsigned x = M->size(); 2786 (*M)[C->body_back()] = x; 2787 } 2788 } 2789 2790 unsigned x = M->size(); 2791 (*M)[Exp] = x; 2792 } 2793 } 2794 2795 // Look at terminators. The condition is a block-level expression. 2796 2797 Stmt* S = (*I)->getTerminatorCondition(); 2798 2799 if (S && M->find(S) == M->end()) { 2800 unsigned x = M->size(); 2801 (*M)[S] = x; 2802 } 2803 } 2804 2805 return M; 2806} 2807 2808CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2809 assert(S != NULL); 2810 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2811 2812 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2813 BlkExprMapTy::iterator I = M->find(S); 2814 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2815} 2816 2817unsigned CFG::getNumBlkExprs() { 2818 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2819 return M->size(); 2820 2821 // We assume callers interested in the number of BlkExprs will want 2822 // the map constructed if it doesn't already exist. 2823 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2824 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2825} 2826 2827//===----------------------------------------------------------------------===// 2828// Filtered walking of the CFG. 2829//===----------------------------------------------------------------------===// 2830 2831bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2832 const CFGBlock *From, const CFGBlock *To) { 2833 2834 if (F.IgnoreDefaultsWithCoveredEnums) { 2835 // If the 'To' has no label or is labeled but the label isn't a 2836 // CaseStmt then filter this edge. 2837 if (const SwitchStmt *S = 2838 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 2839 if (S->isAllEnumCasesCovered()) { 2840 const Stmt *L = To->getLabel(); 2841 if (!L || !isa<CaseStmt>(L)) 2842 return true; 2843 } 2844 } 2845 } 2846 2847 return false; 2848} 2849 2850//===----------------------------------------------------------------------===// 2851// Cleanup: CFG dstor. 2852//===----------------------------------------------------------------------===// 2853 2854CFG::~CFG() { 2855 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2856} 2857 2858//===----------------------------------------------------------------------===// 2859// CFG pretty printing 2860//===----------------------------------------------------------------------===// 2861 2862namespace { 2863 2864class StmtPrinterHelper : public PrinterHelper { 2865 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2866 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2867 StmtMapTy StmtMap; 2868 DeclMapTy DeclMap; 2869 signed CurrentBlock; 2870 unsigned CurrentStmt; 2871 const LangOptions &LangOpts; 2872public: 2873 2874 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2875 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2876 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2877 unsigned j = 1; 2878 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2879 BI != BEnd; ++BI, ++j ) { 2880 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2881 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2882 StmtMap[SE] = P; 2883 2884 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2885 DeclMap[DS->getSingleDecl()] = P; 2886 2887 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2888 if (VarDecl* VD = IS->getConditionVariable()) 2889 DeclMap[VD] = P; 2890 2891 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2892 if (VarDecl* VD = FS->getConditionVariable()) 2893 DeclMap[VD] = P; 2894 2895 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2896 if (VarDecl* VD = WS->getConditionVariable()) 2897 DeclMap[VD] = P; 2898 2899 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2900 if (VarDecl* VD = SS->getConditionVariable()) 2901 DeclMap[VD] = P; 2902 2903 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2904 if (VarDecl* VD = CS->getExceptionDecl()) 2905 DeclMap[VD] = P; 2906 } 2907 } 2908 } 2909 } 2910 } 2911 2912 virtual ~StmtPrinterHelper() {} 2913 2914 const LangOptions &getLangOpts() const { return LangOpts; } 2915 void setBlockID(signed i) { CurrentBlock = i; } 2916 void setStmtID(unsigned i) { CurrentStmt = i; } 2917 2918 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2919 StmtMapTy::iterator I = StmtMap.find(S); 2920 2921 if (I == StmtMap.end()) 2922 return false; 2923 2924 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2925 && I->second.second == CurrentStmt) { 2926 return false; 2927 } 2928 2929 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2930 return true; 2931 } 2932 2933 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2934 DeclMapTy::iterator I = DeclMap.find(D); 2935 2936 if (I == DeclMap.end()) 2937 return false; 2938 2939 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2940 && I->second.second == CurrentStmt) { 2941 return false; 2942 } 2943 2944 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2945 return true; 2946 } 2947}; 2948} // end anonymous namespace 2949 2950 2951namespace { 2952class CFGBlockTerminatorPrint 2953 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2954 2955 llvm::raw_ostream& OS; 2956 StmtPrinterHelper* Helper; 2957 PrintingPolicy Policy; 2958public: 2959 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2960 const PrintingPolicy &Policy) 2961 : OS(os), Helper(helper), Policy(Policy) {} 2962 2963 void VisitIfStmt(IfStmt* I) { 2964 OS << "if "; 2965 I->getCond()->printPretty(OS,Helper,Policy); 2966 } 2967 2968 // Default case. 2969 void VisitStmt(Stmt* Terminator) { 2970 Terminator->printPretty(OS, Helper, Policy); 2971 } 2972 2973 void VisitForStmt(ForStmt* F) { 2974 OS << "for (" ; 2975 if (F->getInit()) 2976 OS << "..."; 2977 OS << "; "; 2978 if (Stmt* C = F->getCond()) 2979 C->printPretty(OS, Helper, Policy); 2980 OS << "; "; 2981 if (F->getInc()) 2982 OS << "..."; 2983 OS << ")"; 2984 } 2985 2986 void VisitWhileStmt(WhileStmt* W) { 2987 OS << "while " ; 2988 if (Stmt* C = W->getCond()) 2989 C->printPretty(OS, Helper, Policy); 2990 } 2991 2992 void VisitDoStmt(DoStmt* D) { 2993 OS << "do ... while "; 2994 if (Stmt* C = D->getCond()) 2995 C->printPretty(OS, Helper, Policy); 2996 } 2997 2998 void VisitSwitchStmt(SwitchStmt* Terminator) { 2999 OS << "switch "; 3000 Terminator->getCond()->printPretty(OS, Helper, Policy); 3001 } 3002 3003 void VisitCXXTryStmt(CXXTryStmt* CS) { 3004 OS << "try ..."; 3005 } 3006 3007 void VisitConditionalOperator(ConditionalOperator* C) { 3008 C->getCond()->printPretty(OS, Helper, Policy); 3009 OS << " ? ... : ..."; 3010 } 3011 3012 void VisitChooseExpr(ChooseExpr* C) { 3013 OS << "__builtin_choose_expr( "; 3014 C->getCond()->printPretty(OS, Helper, Policy); 3015 OS << " )"; 3016 } 3017 3018 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 3019 OS << "goto *"; 3020 I->getTarget()->printPretty(OS, Helper, Policy); 3021 } 3022 3023 void VisitBinaryOperator(BinaryOperator* B) { 3024 if (!B->isLogicalOp()) { 3025 VisitExpr(B); 3026 return; 3027 } 3028 3029 B->getLHS()->printPretty(OS, Helper, Policy); 3030 3031 switch (B->getOpcode()) { 3032 case BO_LOr: 3033 OS << " || ..."; 3034 return; 3035 case BO_LAnd: 3036 OS << " && ..."; 3037 return; 3038 default: 3039 assert(false && "Invalid logical operator."); 3040 } 3041 } 3042 3043 void VisitExpr(Expr* E) { 3044 E->printPretty(OS, Helper, Policy); 3045 } 3046}; 3047} // end anonymous namespace 3048 3049static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3050 const CFGElement &E) { 3051 if (CFGStmt CS = E.getAs<CFGStmt>()) { 3052 Stmt *S = CS; 3053 3054 if (Helper) { 3055 3056 // special printing for statement-expressions. 3057 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3058 CompoundStmt* Sub = SE->getSubStmt(); 3059 3060 if (Sub->child_begin() != Sub->child_end()) { 3061 OS << "({ ... ; "; 3062 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3063 OS << " })\n"; 3064 return; 3065 } 3066 } 3067 // special printing for comma expressions. 3068 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3069 if (B->getOpcode() == BO_Comma) { 3070 OS << "... , "; 3071 Helper->handledStmt(B->getRHS(),OS); 3072 OS << '\n'; 3073 return; 3074 } 3075 } 3076 } 3077 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3078 3079 if (isa<CXXOperatorCallExpr>(S)) { 3080 OS << " (OperatorCall)"; 3081 } else if (isa<CXXBindTemporaryExpr>(S)) { 3082 OS << " (BindTemporary)"; 3083 } 3084 3085 if (CS.asLValue()) 3086 OS << " (asLValue)"; 3087 3088 // Expressions need a newline. 3089 if (isa<Expr>(S)) 3090 OS << '\n'; 3091 3092 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 3093 CXXBaseOrMemberInitializer* I = IE; 3094 if (I->isBaseInitializer()) 3095 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3096 else OS << I->getAnyMember()->getName(); 3097 3098 OS << "("; 3099 if (Expr* IE = I->getInit()) 3100 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3101 OS << ")"; 3102 3103 if (I->isBaseInitializer()) 3104 OS << " (Base initializer)\n"; 3105 else OS << " (Member initializer)\n"; 3106 3107 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 3108 VarDecl* VD = DE.getVarDecl(); 3109 Helper->handleDecl(VD, OS); 3110 3111 const Type* T = VD->getType().getTypePtr(); 3112 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3113 T = RT->getPointeeType().getTypePtr(); 3114 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3115 T = ET; 3116 3117 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3118 OS << " (Implicit destructor)\n"; 3119 3120 } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { 3121 const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); 3122 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3123 OS << " (Base object destructor)\n"; 3124 3125 } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { 3126 FieldDecl *FD = ME.getFieldDecl(); 3127 3128 const Type *T = FD->getType().getTypePtr(); 3129 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3130 T = ET; 3131 3132 OS << "this->" << FD->getName(); 3133 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3134 OS << " (Member object destructor)\n"; 3135 3136 } else if (CFGTemporaryDtor TE = E.getAs<CFGTemporaryDtor>()) { 3137 CXXBindTemporaryExpr *BT = TE.getBindTemporaryExpr(); 3138 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3139 OS << " (Temporary object destructor)\n"; 3140 } 3141} 3142 3143static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3144 const CFGBlock& B, 3145 StmtPrinterHelper* Helper, bool print_edges) { 3146 3147 if (Helper) Helper->setBlockID(B.getBlockID()); 3148 3149 // Print the header. 3150 OS << "\n [ B" << B.getBlockID(); 3151 3152 if (&B == &cfg->getEntry()) 3153 OS << " (ENTRY) ]\n"; 3154 else if (&B == &cfg->getExit()) 3155 OS << " (EXIT) ]\n"; 3156 else if (&B == cfg->getIndirectGotoBlock()) 3157 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3158 else 3159 OS << " ]\n"; 3160 3161 // Print the label of this block. 3162 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3163 3164 if (print_edges) 3165 OS << " "; 3166 3167 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3168 OS << L->getName(); 3169 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3170 OS << "case "; 3171 C->getLHS()->printPretty(OS, Helper, 3172 PrintingPolicy(Helper->getLangOpts())); 3173 if (C->getRHS()) { 3174 OS << " ... "; 3175 C->getRHS()->printPretty(OS, Helper, 3176 PrintingPolicy(Helper->getLangOpts())); 3177 } 3178 } else if (isa<DefaultStmt>(Label)) 3179 OS << "default"; 3180 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3181 OS << "catch ("; 3182 if (CS->getExceptionDecl()) 3183 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3184 0); 3185 else 3186 OS << "..."; 3187 OS << ")"; 3188 3189 } else 3190 assert(false && "Invalid label statement in CFGBlock."); 3191 3192 OS << ":\n"; 3193 } 3194 3195 // Iterate through the statements in the block and print them. 3196 unsigned j = 1; 3197 3198 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3199 I != E ; ++I, ++j ) { 3200 3201 // Print the statement # in the basic block and the statement itself. 3202 if (print_edges) 3203 OS << " "; 3204 3205 OS << llvm::format("%3d", j) << ": "; 3206 3207 if (Helper) 3208 Helper->setStmtID(j); 3209 3210 print_elem(OS,Helper,*I); 3211 } 3212 3213 // Print the terminator of this block. 3214 if (B.getTerminator()) { 3215 if (print_edges) 3216 OS << " "; 3217 3218 OS << " T: "; 3219 3220 if (Helper) Helper->setBlockID(-1); 3221 3222 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3223 PrintingPolicy(Helper->getLangOpts())); 3224 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3225 OS << '\n'; 3226 } 3227 3228 if (print_edges) { 3229 // Print the predecessors of this block. 3230 OS << " Predecessors (" << B.pred_size() << "):"; 3231 unsigned i = 0; 3232 3233 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3234 I != E; ++I, ++i) { 3235 3236 if (i == 8 || (i-8) == 0) 3237 OS << "\n "; 3238 3239 OS << " B" << (*I)->getBlockID(); 3240 } 3241 3242 OS << '\n'; 3243 3244 // Print the successors of this block. 3245 OS << " Successors (" << B.succ_size() << "):"; 3246 i = 0; 3247 3248 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3249 I != E; ++I, ++i) { 3250 3251 if (i == 8 || (i-8) % 10 == 0) 3252 OS << "\n "; 3253 3254 if (*I) 3255 OS << " B" << (*I)->getBlockID(); 3256 else 3257 OS << " NULL"; 3258 } 3259 3260 OS << '\n'; 3261 } 3262} 3263 3264 3265/// dump - A simple pretty printer of a CFG that outputs to stderr. 3266void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3267 3268/// print - A simple pretty printer of a CFG that outputs to an ostream. 3269void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3270 StmtPrinterHelper Helper(this, LO); 3271 3272 // Print the entry block. 3273 print_block(OS, this, getEntry(), &Helper, true); 3274 3275 // Iterate through the CFGBlocks and print them one by one. 3276 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3277 // Skip the entry block, because we already printed it. 3278 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3279 continue; 3280 3281 print_block(OS, this, **I, &Helper, true); 3282 } 3283 3284 // Print the exit block. 3285 print_block(OS, this, getExit(), &Helper, true); 3286 OS.flush(); 3287} 3288 3289/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3290void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3291 print(llvm::errs(), cfg, LO); 3292} 3293 3294/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3295/// Generally this will only be called from CFG::print. 3296void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3297 const LangOptions &LO) const { 3298 StmtPrinterHelper Helper(cfg, LO); 3299 print_block(OS, cfg, *this, &Helper, true); 3300} 3301 3302/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3303void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3304 const LangOptions &LO) const { 3305 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3306 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3307} 3308 3309Stmt* CFGBlock::getTerminatorCondition() { 3310 Stmt *Terminator = this->Terminator; 3311 if (!Terminator) 3312 return NULL; 3313 3314 Expr* E = NULL; 3315 3316 switch (Terminator->getStmtClass()) { 3317 default: 3318 break; 3319 3320 case Stmt::ForStmtClass: 3321 E = cast<ForStmt>(Terminator)->getCond(); 3322 break; 3323 3324 case Stmt::WhileStmtClass: 3325 E = cast<WhileStmt>(Terminator)->getCond(); 3326 break; 3327 3328 case Stmt::DoStmtClass: 3329 E = cast<DoStmt>(Terminator)->getCond(); 3330 break; 3331 3332 case Stmt::IfStmtClass: 3333 E = cast<IfStmt>(Terminator)->getCond(); 3334 break; 3335 3336 case Stmt::ChooseExprClass: 3337 E = cast<ChooseExpr>(Terminator)->getCond(); 3338 break; 3339 3340 case Stmt::IndirectGotoStmtClass: 3341 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3342 break; 3343 3344 case Stmt::SwitchStmtClass: 3345 E = cast<SwitchStmt>(Terminator)->getCond(); 3346 break; 3347 3348 case Stmt::ConditionalOperatorClass: 3349 E = cast<ConditionalOperator>(Terminator)->getCond(); 3350 break; 3351 3352 case Stmt::BinaryOperatorClass: // '&&' and '||' 3353 E = cast<BinaryOperator>(Terminator)->getLHS(); 3354 break; 3355 3356 case Stmt::ObjCForCollectionStmtClass: 3357 return Terminator; 3358 } 3359 3360 return E ? E->IgnoreParens() : NULL; 3361} 3362 3363bool CFGBlock::hasBinaryBranchTerminator() const { 3364 const Stmt *Terminator = this->Terminator; 3365 if (!Terminator) 3366 return false; 3367 3368 Expr* E = NULL; 3369 3370 switch (Terminator->getStmtClass()) { 3371 default: 3372 return false; 3373 3374 case Stmt::ForStmtClass: 3375 case Stmt::WhileStmtClass: 3376 case Stmt::DoStmtClass: 3377 case Stmt::IfStmtClass: 3378 case Stmt::ChooseExprClass: 3379 case Stmt::ConditionalOperatorClass: 3380 case Stmt::BinaryOperatorClass: 3381 return true; 3382 } 3383 3384 return E ? E->IgnoreParens() : NULL; 3385} 3386 3387 3388//===----------------------------------------------------------------------===// 3389// CFG Graphviz Visualization 3390//===----------------------------------------------------------------------===// 3391 3392 3393#ifndef NDEBUG 3394static StmtPrinterHelper* GraphHelper; 3395#endif 3396 3397void CFG::viewCFG(const LangOptions &LO) const { 3398#ifndef NDEBUG 3399 StmtPrinterHelper H(this, LO); 3400 GraphHelper = &H; 3401 llvm::ViewGraph(this,"CFG"); 3402 GraphHelper = NULL; 3403#endif 3404} 3405 3406namespace llvm { 3407template<> 3408struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3409 3410 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3411 3412 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3413 3414#ifndef NDEBUG 3415 std::string OutSStr; 3416 llvm::raw_string_ostream Out(OutSStr); 3417 print_block(Out,Graph, *Node, GraphHelper, false); 3418 std::string& OutStr = Out.str(); 3419 3420 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3421 3422 // Process string output to make it nicer... 3423 for (unsigned i = 0; i != OutStr.length(); ++i) 3424 if (OutStr[i] == '\n') { // Left justify 3425 OutStr[i] = '\\'; 3426 OutStr.insert(OutStr.begin()+i+1, 'l'); 3427 } 3428 3429 return OutStr; 3430#else 3431 return ""; 3432#endif 3433 } 3434}; 3435} // end namespace llvm 3436