CFG.cpp revision 7502c1d3ce8bb97bcc4f7bebef507040bd93b26f
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 return D->getLocation(); 36} 37 38/// The CFG builder uses a recursive algorithm to build the CFG. When 39/// we process an expression, sometimes we know that we must add the 40/// subexpressions as block-level expressions. For example: 41/// 42/// exp1 || exp2 43/// 44/// When processing the '||' expression, we know that exp1 and exp2 45/// need to be added as block-level expressions, even though they 46/// might not normally need to be. AddStmtChoice records this 47/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 48/// the builder has an option not to add a subexpression as a 49/// block-level expression. 50/// 51class AddStmtChoice { 52public: 53 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 54 55 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 56 57 bool alwaysAdd() const { return kind & AlwaysAdd; } 58 59 /// Return a copy of this object, except with the 'always-add' bit 60 /// set as specified. 61 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 62 return AddStmtChoice(alwaysAdd ? Kind(kind | AlwaysAdd) : 63 Kind(kind & ~AlwaysAdd)); 64 } 65 66private: 67 Kind kind; 68}; 69 70/// LocalScope - Node in tree of local scopes created for C++ implicit 71/// destructor calls generation. It contains list of automatic variables 72/// declared in the scope and link to position in previous scope this scope 73/// began in. 74/// 75/// The process of creating local scopes is as follows: 76/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 77/// - Before processing statements in scope (e.g. CompoundStmt) create 78/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 79/// and set CFGBuilder::ScopePos to the end of new scope, 80/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 81/// at this VarDecl, 82/// - For every normal (without jump) end of scope add to CFGBlock destructors 83/// for objects in the current scope, 84/// - For every jump add to CFGBlock destructors for objects 85/// between CFGBuilder::ScopePos and local scope position saved for jump 86/// target. Thanks to C++ restrictions on goto jumps we can be sure that 87/// jump target position will be on the path to root from CFGBuilder::ScopePos 88/// (adding any variable that doesn't need constructor to be called to 89/// LocalScope can break this assumption), 90/// 91class LocalScope { 92public: 93 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 94 95 /// const_iterator - Iterates local scope backwards and jumps to previous 96 /// scope on reaching the beginning of currently iterated scope. 97 class const_iterator { 98 const LocalScope* Scope; 99 100 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 101 /// Invalid iterator (with null Scope) has VarIter equal to 0. 102 unsigned VarIter; 103 104 public: 105 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 106 /// Incrementing invalid iterator is allowed and will result in invalid 107 /// iterator. 108 const_iterator() 109 : Scope(NULL), VarIter(0) {} 110 111 /// Create valid iterator. In case when S.Prev is an invalid iterator and 112 /// I is equal to 0, this will create invalid iterator. 113 const_iterator(const LocalScope& S, unsigned I) 114 : Scope(&S), VarIter(I) { 115 // Iterator to "end" of scope is not allowed. Handle it by going up 116 // in scopes tree possibly up to invalid iterator in the root. 117 if (VarIter == 0 && Scope) 118 *this = Scope->Prev; 119 } 120 121 VarDecl* const* operator->() const { 122 assert (Scope && "Dereferencing invalid iterator is not allowed"); 123 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 124 return &Scope->Vars[VarIter - 1]; 125 } 126 VarDecl* operator*() const { 127 return *this->operator->(); 128 } 129 130 const_iterator& operator++() { 131 if (!Scope) 132 return *this; 133 134 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 135 --VarIter; 136 if (VarIter == 0) 137 *this = Scope->Prev; 138 return *this; 139 } 140 const_iterator operator++(int) { 141 const_iterator P = *this; 142 ++*this; 143 return P; 144 } 145 146 bool operator==(const const_iterator& rhs) const { 147 return Scope == rhs.Scope && VarIter == rhs.VarIter; 148 } 149 bool operator!=(const const_iterator& rhs) const { 150 return !(*this == rhs); 151 } 152 153 operator bool() const { 154 return *this != const_iterator(); 155 } 156 157 int distance(const_iterator L); 158 }; 159 160 friend class const_iterator; 161 162private: 163 /// Automatic variables in order of declaration. 164 AutomaticVarsTy Vars; 165 /// Iterator to variable in previous scope that was declared just before 166 /// begin of this scope. 167 const_iterator Prev; 168 169public: 170 /// Constructs empty scope linked to previous scope in specified place. 171 LocalScope(const_iterator P) 172 : Vars() 173 , Prev(P) {} 174 175 /// Begin of scope in direction of CFG building (backwards). 176 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 177 178 void addVar(VarDecl* VD) { 179 Vars.push_back(VD); 180 } 181}; 182 183/// distance - Calculates distance from this to L. L must be reachable from this 184/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 185/// number of scopes between this and L. 186int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 187 int D = 0; 188 const_iterator F = *this; 189 while (F.Scope != L.Scope) { 190 assert (F != const_iterator() 191 && "L iterator is not reachable from F iterator."); 192 D += F.VarIter; 193 F = F.Scope->Prev; 194 } 195 D += F.VarIter - L.VarIter; 196 return D; 197} 198 199/// BlockScopePosPair - Structure for specifying position in CFG during its 200/// build process. It consists of CFGBlock that specifies position in CFG graph 201/// and LocalScope::const_iterator that specifies position in LocalScope graph. 202struct BlockScopePosPair { 203 BlockScopePosPair() : block(0) {} 204 BlockScopePosPair(CFGBlock* b, LocalScope::const_iterator scopePos) 205 : block(b), scopePosition(scopePos) {} 206 207 CFGBlock *block; 208 LocalScope::const_iterator scopePosition; 209}; 210 211/// CFGBuilder - This class implements CFG construction from an AST. 212/// The builder is stateful: an instance of the builder should be used to only 213/// construct a single CFG. 214/// 215/// Example usage: 216/// 217/// CFGBuilder builder; 218/// CFG* cfg = builder.BuildAST(stmt1); 219/// 220/// CFG construction is done via a recursive walk of an AST. We actually parse 221/// the AST in reverse order so that the successor of a basic block is 222/// constructed prior to its predecessor. This allows us to nicely capture 223/// implicit fall-throughs without extra basic blocks. 224/// 225class CFGBuilder { 226 typedef BlockScopePosPair JumpTarget; 227 typedef BlockScopePosPair JumpSource; 228 229 ASTContext *Context; 230 llvm::OwningPtr<CFG> cfg; 231 232 CFGBlock* Block; 233 CFGBlock* Succ; 234 JumpTarget ContinueJumpTarget; 235 JumpTarget BreakJumpTarget; 236 CFGBlock* SwitchTerminatedBlock; 237 CFGBlock* DefaultCaseBlock; 238 CFGBlock* TryTerminatedBlock; 239 240 // Current position in local scope. 241 LocalScope::const_iterator ScopePos; 242 243 // LabelMap records the mapping from Label expressions to their jump targets. 244 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 245 LabelMapTy LabelMap; 246 247 // A list of blocks that end with a "goto" that must be backpatched to their 248 // resolved targets upon completion of CFG construction. 249 typedef std::vector<JumpSource> BackpatchBlocksTy; 250 BackpatchBlocksTy BackpatchBlocks; 251 252 // A list of labels whose address has been taken (for indirect gotos). 253 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 254 LabelSetTy AddressTakenLabels; 255 256 bool badCFG; 257 CFG::BuildOptions BuildOpts; 258 259public: 260 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 261 Block(NULL), Succ(NULL), 262 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 263 TryTerminatedBlock(NULL), badCFG(false) {} 264 265 // buildCFG - Used by external clients to construct the CFG. 266 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 267 CFG::BuildOptions BO); 268 269private: 270 // Visitors to walk an AST and construct the CFG. 271 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 272 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 273 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 274 CFGBlock *VisitBreakStmt(BreakStmt *B); 275 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 276 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 277 AddStmtChoice asc); 278 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 279 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 280 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 281 AddStmtChoice asc); 282 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 283 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 284 AddStmtChoice asc); 285 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 286 AddStmtChoice asc); 287 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 288 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 289 CFGBlock *VisitCaseStmt(CaseStmt *C); 290 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 291 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 292 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 293 CFGBlock *VisitContinueStmt(ContinueStmt *C); 294 CFGBlock *VisitDeclStmt(DeclStmt *DS); 295 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 296 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 297 CFGBlock *VisitDoStmt(DoStmt *D); 298 CFGBlock *VisitForStmt(ForStmt *F); 299 CFGBlock *VisitGotoStmt(GotoStmt* G); 300 CFGBlock *VisitIfStmt(IfStmt *I); 301 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 302 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 303 CFGBlock *VisitLabelStmt(LabelStmt *L); 304 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 305 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 306 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 307 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 308 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 309 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 310 CFGBlock *VisitReturnStmt(ReturnStmt* R); 311 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 312 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 313 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 314 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 315 CFGBlock *VisitWhileStmt(WhileStmt *W); 316 317 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 318 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 319 CFGBlock *VisitChildren(Stmt* S); 320 321 // Visitors to walk an AST and generate destructors of temporaries in 322 // full expression. 323 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 324 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 325 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 326 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 327 bool BindToTemporary); 328 CFGBlock *VisitConditionalOperatorForTemporaryDtors(ConditionalOperator *E, 329 bool BindToTemporary); 330 331 // NYS == Not Yet Supported 332 CFGBlock* NYS() { 333 badCFG = true; 334 return Block; 335 } 336 337 void autoCreateBlock() { if (!Block) Block = createBlock(); } 338 CFGBlock *createBlock(bool add_successor = true); 339 340 CFGBlock *addStmt(Stmt *S) { 341 return Visit(S, AddStmtChoice::AlwaysAdd); 342 } 343 CFGBlock *addInitializer(CXXCtorInitializer *I); 344 void addAutomaticObjDtors(LocalScope::const_iterator B, 345 LocalScope::const_iterator E, Stmt* S); 346 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 347 348 // Local scopes creation. 349 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 350 351 void addLocalScopeForStmt(Stmt* S); 352 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 353 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 354 355 void addLocalScopeAndDtors(Stmt* S); 356 357 // Interface to CFGBlock - adding CFGElements. 358 void appendStmt(CFGBlock *B, Stmt *S, 359 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 360 B->appendStmt(S, cfg->getBumpVectorContext()); 361 } 362 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 363 B->appendInitializer(I, cfg->getBumpVectorContext()); 364 } 365 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 366 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 367 } 368 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 369 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 370 } 371 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 372 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 373 } 374 375 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 376 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 377 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 378 LocalScope::const_iterator E, Stmt* S); 379 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 380 LocalScope::const_iterator B, LocalScope::const_iterator E); 381 382 void addSuccessor(CFGBlock *B, CFGBlock *S) { 383 B->addSuccessor(S, cfg->getBumpVectorContext()); 384 } 385 386 /// TryResult - a class representing a variant over the values 387 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 388 /// and is used by the CFGBuilder to decide if a branch condition 389 /// can be decided up front during CFG construction. 390 class TryResult { 391 int X; 392 public: 393 TryResult(bool b) : X(b ? 1 : 0) {} 394 TryResult() : X(-1) {} 395 396 bool isTrue() const { return X == 1; } 397 bool isFalse() const { return X == 0; } 398 bool isKnown() const { return X >= 0; } 399 void negate() { 400 assert(isKnown()); 401 X ^= 0x1; 402 } 403 }; 404 405 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 406 /// if we can evaluate to a known value, otherwise return -1. 407 TryResult tryEvaluateBool(Expr *S) { 408 if (!BuildOpts.PruneTriviallyFalseEdges) 409 return TryResult(); 410 411 Expr::EvalResult Result; 412 if (!S->isTypeDependent() && !S->isValueDependent() && 413 S->Evaluate(Result, *Context) && Result.Val.isInt()) 414 return Result.Val.getInt().getBoolValue(); 415 416 return TryResult(); 417 } 418}; 419 420// FIXME: Add support for dependent-sized array types in C++? 421// Does it even make sense to build a CFG for an uninstantiated template? 422static const VariableArrayType *FindVA(const Type *t) { 423 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 424 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 425 if (vat->getSizeExpr()) 426 return vat; 427 428 t = vt->getElementType().getTypePtr(); 429 } 430 431 return 0; 432} 433 434/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 435/// arbitrary statement. Examples include a single expression or a function 436/// body (compound statement). The ownership of the returned CFG is 437/// transferred to the caller. If CFG construction fails, this method returns 438/// NULL. 439CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 440 CFG::BuildOptions BO) { 441 442 Context = C; 443 assert(cfg.get()); 444 if (!Statement) 445 return NULL; 446 447 BuildOpts = BO; 448 449 // Create an empty block that will serve as the exit block for the CFG. Since 450 // this is the first block added to the CFG, it will be implicitly registered 451 // as the exit block. 452 Succ = createBlock(); 453 assert(Succ == &cfg->getExit()); 454 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 455 456 if (BuildOpts.AddImplicitDtors) 457 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 458 addImplicitDtorsForDestructor(DD); 459 460 // Visit the statements and create the CFG. 461 CFGBlock *B = addStmt(Statement); 462 463 if (badCFG) 464 return NULL; 465 466 // For C++ constructor add initializers to CFG. 467 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 468 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 469 E = CD->init_rend(); I != E; ++I) { 470 B = addInitializer(*I); 471 if (badCFG) 472 return NULL; 473 } 474 } 475 476 if (B) 477 Succ = B; 478 479 // Backpatch the gotos whose label -> block mappings we didn't know when we 480 // encountered them. 481 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 482 E = BackpatchBlocks.end(); I != E; ++I ) { 483 484 CFGBlock* B = I->block; 485 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 486 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 487 488 // If there is no target for the goto, then we are looking at an 489 // incomplete AST. Handle this by not registering a successor. 490 if (LI == LabelMap.end()) continue; 491 492 JumpTarget JT = LI->second; 493 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 494 JT.scopePosition); 495 addSuccessor(B, JT.block); 496 } 497 498 // Add successors to the Indirect Goto Dispatch block (if we have one). 499 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 500 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 501 E = AddressTakenLabels.end(); I != E; ++I ) { 502 503 // Lookup the target block. 504 LabelMapTy::iterator LI = LabelMap.find(*I); 505 506 // If there is no target block that contains label, then we are looking 507 // at an incomplete AST. Handle this by not registering a successor. 508 if (LI == LabelMap.end()) continue; 509 510 addSuccessor(B, LI->second.block); 511 } 512 513 // Create an empty entry block that has no predecessors. 514 cfg->setEntry(createBlock()); 515 516 return cfg.take(); 517} 518 519/// createBlock - Used to lazily create blocks that are connected 520/// to the current (global) succcessor. 521CFGBlock* CFGBuilder::createBlock(bool add_successor) { 522 CFGBlock* B = cfg->createBlock(); 523 if (add_successor && Succ) 524 addSuccessor(B, Succ); 525 return B; 526} 527 528/// addInitializer - Add C++ base or member initializer element to CFG. 529CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 530 if (!BuildOpts.AddInitializers) 531 return Block; 532 533 bool IsReference = false; 534 bool HasTemporaries = false; 535 536 // Destructors of temporaries in initialization expression should be called 537 // after initialization finishes. 538 Expr *Init = I->getInit(); 539 if (Init) { 540 if (FieldDecl *FD = I->getAnyMember()) 541 IsReference = FD->getType()->isReferenceType(); 542 HasTemporaries = isa<ExprWithCleanups>(Init); 543 544 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 545 // Generate destructors for temporaries in initialization expression. 546 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 547 IsReference); 548 } 549 } 550 551 autoCreateBlock(); 552 appendInitializer(Block, I); 553 554 if (Init) { 555 if (HasTemporaries) { 556 // For expression with temporaries go directly to subexpression to omit 557 // generating destructors for the second time. 558 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 559 } 560 return Visit(Init); 561 } 562 563 return Block; 564} 565 566/// addAutomaticObjDtors - Add to current block automatic objects destructors 567/// for objects in range of local scope positions. Use S as trigger statement 568/// for destructors. 569void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 570 LocalScope::const_iterator E, Stmt* S) { 571 if (!BuildOpts.AddImplicitDtors) 572 return; 573 574 if (B == E) 575 return; 576 577 autoCreateBlock(); 578 appendAutomaticObjDtors(Block, B, E, S); 579} 580 581/// addImplicitDtorsForDestructor - Add implicit destructors generated for 582/// base and member objects in destructor. 583void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 584 assert (BuildOpts.AddImplicitDtors 585 && "Can be called only when dtors should be added"); 586 const CXXRecordDecl *RD = DD->getParent(); 587 588 // At the end destroy virtual base objects. 589 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 590 VE = RD->vbases_end(); VI != VE; ++VI) { 591 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 592 if (!CD->hasTrivialDestructor()) { 593 autoCreateBlock(); 594 appendBaseDtor(Block, VI); 595 } 596 } 597 598 // Before virtual bases destroy direct base objects. 599 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 600 BE = RD->bases_end(); BI != BE; ++BI) { 601 if (!BI->isVirtual()) { 602 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 603 if (!CD->hasTrivialDestructor()) { 604 autoCreateBlock(); 605 appendBaseDtor(Block, BI); 606 } 607 } 608 } 609 610 // First destroy member objects. 611 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 612 FE = RD->field_end(); FI != FE; ++FI) { 613 // Check for constant size array. Set type to array element type. 614 QualType QT = FI->getType(); 615 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 616 if (AT->getSize() == 0) 617 continue; 618 QT = AT->getElementType(); 619 } 620 621 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 622 if (!CD->hasTrivialDestructor()) { 623 autoCreateBlock(); 624 appendMemberDtor(Block, *FI); 625 } 626 } 627} 628 629/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 630/// way return valid LocalScope object. 631LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 632 if (!Scope) { 633 Scope = cfg->getAllocator().Allocate<LocalScope>(); 634 new (Scope) LocalScope(ScopePos); 635 } 636 return Scope; 637} 638 639/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 640/// that should create implicit scope (e.g. if/else substatements). 641void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 642 if (!BuildOpts.AddImplicitDtors) 643 return; 644 645 LocalScope *Scope = 0; 646 647 // For compound statement we will be creating explicit scope. 648 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 649 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 650 ; BI != BE; ++BI) { 651 Stmt* SI = *BI; 652 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 653 SI = LS->getSubStmt(); 654 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 655 Scope = addLocalScopeForDeclStmt(DS, Scope); 656 } 657 return; 658 } 659 660 // For any other statement scope will be implicit and as such will be 661 // interesting only for DeclStmt. 662 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 663 S = LS->getSubStmt(); 664 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 665 addLocalScopeForDeclStmt(DS); 666} 667 668/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 669/// reuse Scope if not NULL. 670LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 671 LocalScope* Scope) { 672 if (!BuildOpts.AddImplicitDtors) 673 return Scope; 674 675 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 676 ; DI != DE; ++DI) { 677 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 678 Scope = addLocalScopeForVarDecl(VD, Scope); 679 } 680 return Scope; 681} 682 683/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 684/// create add scope for automatic objects and temporary objects bound to 685/// const reference. Will reuse Scope if not NULL. 686LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 687 LocalScope* Scope) { 688 if (!BuildOpts.AddImplicitDtors) 689 return Scope; 690 691 // Check if variable is local. 692 switch (VD->getStorageClass()) { 693 case SC_None: 694 case SC_Auto: 695 case SC_Register: 696 break; 697 default: return Scope; 698 } 699 700 // Check for const references bound to temporary. Set type to pointee. 701 QualType QT = VD->getType(); 702 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 703 QT = RT->getPointeeType(); 704 if (!QT.isConstQualified()) 705 return Scope; 706 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 707 return Scope; 708 } 709 710 // Check for constant size array. Set type to array element type. 711 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 712 if (AT->getSize() == 0) 713 return Scope; 714 QT = AT->getElementType(); 715 } 716 717 // Check if type is a C++ class with non-trivial destructor. 718 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 719 if (!CD->hasTrivialDestructor()) { 720 // Add the variable to scope 721 Scope = createOrReuseLocalScope(Scope); 722 Scope->addVar(VD); 723 ScopePos = Scope->begin(); 724 } 725 return Scope; 726} 727 728/// addLocalScopeAndDtors - For given statement add local scope for it and 729/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 730void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 731 if (!BuildOpts.AddImplicitDtors) 732 return; 733 734 LocalScope::const_iterator scopeBeginPos = ScopePos; 735 addLocalScopeForStmt(S); 736 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 737} 738 739/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 740/// automatic storage duration to CFGBlock's elements vector. Insertion will be 741/// performed in place specified with iterator. 742void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 743 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 744 BumpVectorContext& C = cfg->getBumpVectorContext(); 745 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 746 while (B != E) 747 I = Blk->insertAutomaticObjDtor(I, *B++, S); 748} 749 750/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 751/// automatic storage duration to CFGBlock's elements vector. Elements will be 752/// appended to physical end of the vector which happens to be logical 753/// beginning. 754void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 755 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 756 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 757} 758 759/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 760/// variables with automatic storage duration to CFGBlock's elements vector. 761/// Elements will be prepended to physical beginning of the vector which 762/// happens to be logical end. Use blocks terminator as statement that specifies 763/// destructors call site. 764void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 765 LocalScope::const_iterator B, LocalScope::const_iterator E) { 766 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 767} 768 769/// Visit - Walk the subtree of a statement and add extra 770/// blocks for ternary operators, &&, and ||. We also process "," and 771/// DeclStmts (which may contain nested control-flow). 772CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 773tryAgain: 774 if (!S) { 775 badCFG = true; 776 return 0; 777 } 778 switch (S->getStmtClass()) { 779 default: 780 return VisitStmt(S, asc); 781 782 case Stmt::AddrLabelExprClass: 783 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 784 785 case Stmt::BinaryOperatorClass: 786 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 787 788 case Stmt::BlockExprClass: 789 return VisitBlockExpr(cast<BlockExpr>(S), asc); 790 791 case Stmt::BreakStmtClass: 792 return VisitBreakStmt(cast<BreakStmt>(S)); 793 794 case Stmt::CallExprClass: 795 case Stmt::CXXOperatorCallExprClass: 796 return VisitCallExpr(cast<CallExpr>(S), asc); 797 798 case Stmt::CaseStmtClass: 799 return VisitCaseStmt(cast<CaseStmt>(S)); 800 801 case Stmt::ChooseExprClass: 802 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 803 804 case Stmt::CompoundStmtClass: 805 return VisitCompoundStmt(cast<CompoundStmt>(S)); 806 807 case Stmt::ConditionalOperatorClass: 808 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 809 810 case Stmt::ContinueStmtClass: 811 return VisitContinueStmt(cast<ContinueStmt>(S)); 812 813 case Stmt::CXXCatchStmtClass: 814 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 815 816 case Stmt::ExprWithCleanupsClass: 817 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 818 819 case Stmt::CXXBindTemporaryExprClass: 820 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 821 822 case Stmt::CXXConstructExprClass: 823 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 824 825 case Stmt::CXXFunctionalCastExprClass: 826 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 827 828 case Stmt::CXXTemporaryObjectExprClass: 829 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 830 831 case Stmt::CXXMemberCallExprClass: 832 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 833 834 case Stmt::CXXThrowExprClass: 835 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 836 837 case Stmt::CXXTryStmtClass: 838 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 839 840 case Stmt::DeclStmtClass: 841 return VisitDeclStmt(cast<DeclStmt>(S)); 842 843 case Stmt::DefaultStmtClass: 844 return VisitDefaultStmt(cast<DefaultStmt>(S)); 845 846 case Stmt::DoStmtClass: 847 return VisitDoStmt(cast<DoStmt>(S)); 848 849 case Stmt::ForStmtClass: 850 return VisitForStmt(cast<ForStmt>(S)); 851 852 case Stmt::GotoStmtClass: 853 return VisitGotoStmt(cast<GotoStmt>(S)); 854 855 case Stmt::IfStmtClass: 856 return VisitIfStmt(cast<IfStmt>(S)); 857 858 case Stmt::ImplicitCastExprClass: 859 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 860 861 case Stmt::IndirectGotoStmtClass: 862 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 863 864 case Stmt::LabelStmtClass: 865 return VisitLabelStmt(cast<LabelStmt>(S)); 866 867 case Stmt::MemberExprClass: 868 return VisitMemberExpr(cast<MemberExpr>(S), asc); 869 870 case Stmt::ObjCAtCatchStmtClass: 871 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 872 873 case Stmt::ObjCAtSynchronizedStmtClass: 874 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 875 876 case Stmt::ObjCAtThrowStmtClass: 877 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 878 879 case Stmt::ObjCAtTryStmtClass: 880 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 881 882 case Stmt::ObjCForCollectionStmtClass: 883 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 884 885 case Stmt::ParenExprClass: 886 S = cast<ParenExpr>(S)->getSubExpr(); 887 goto tryAgain; 888 889 case Stmt::NullStmtClass: 890 return Block; 891 892 case Stmt::ReturnStmtClass: 893 return VisitReturnStmt(cast<ReturnStmt>(S)); 894 895 case Stmt::SizeOfAlignOfExprClass: 896 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 897 898 case Stmt::StmtExprClass: 899 return VisitStmtExpr(cast<StmtExpr>(S), asc); 900 901 case Stmt::SwitchStmtClass: 902 return VisitSwitchStmt(cast<SwitchStmt>(S)); 903 904 case Stmt::UnaryOperatorClass: 905 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 906 907 case Stmt::WhileStmtClass: 908 return VisitWhileStmt(cast<WhileStmt>(S)); 909 } 910} 911 912CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 913 if (asc.alwaysAdd()) { 914 autoCreateBlock(); 915 appendStmt(Block, S, asc); 916 } 917 918 return VisitChildren(S); 919} 920 921/// VisitChildren - Visit the children of a Stmt. 922CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 923 CFGBlock *B = Block; 924 for (Stmt::child_range I = Terminator->children(); I; ++I) { 925 if (*I) B = Visit(*I); 926 } 927 return B; 928} 929 930CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 931 AddStmtChoice asc) { 932 AddressTakenLabels.insert(A->getLabel()); 933 934 if (asc.alwaysAdd()) { 935 autoCreateBlock(); 936 appendStmt(Block, A, asc); 937 } 938 939 return Block; 940} 941 942CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 943 AddStmtChoice asc) { 944 if (asc.alwaysAdd()) { 945 autoCreateBlock(); 946 appendStmt(Block, U, asc); 947 } 948 949 return Visit(U->getSubExpr(), AddStmtChoice()); 950} 951 952CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 953 AddStmtChoice asc) { 954 if (B->isLogicalOp()) { // && or || 955 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 956 appendStmt(ConfluenceBlock, B, asc); 957 958 if (badCFG) 959 return 0; 960 961 // create the block evaluating the LHS 962 CFGBlock* LHSBlock = createBlock(false); 963 LHSBlock->setTerminator(B); 964 965 // create the block evaluating the RHS 966 Succ = ConfluenceBlock; 967 Block = NULL; 968 CFGBlock* RHSBlock = addStmt(B->getRHS()); 969 970 if (RHSBlock) { 971 if (badCFG) 972 return 0; 973 } else { 974 // Create an empty block for cases where the RHS doesn't require 975 // any explicit statements in the CFG. 976 RHSBlock = createBlock(); 977 } 978 979 // See if this is a known constant. 980 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 981 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 982 KnownVal.negate(); 983 984 // Now link the LHSBlock with RHSBlock. 985 if (B->getOpcode() == BO_LOr) { 986 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 987 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 988 } else { 989 assert(B->getOpcode() == BO_LAnd); 990 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 991 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 992 } 993 994 // Generate the blocks for evaluating the LHS. 995 Block = LHSBlock; 996 return addStmt(B->getLHS()); 997 } 998 999 if (B->getOpcode() == BO_Comma) { // , 1000 autoCreateBlock(); 1001 appendStmt(Block, B, asc); 1002 addStmt(B->getRHS()); 1003 return addStmt(B->getLHS()); 1004 } 1005 1006 if (B->isAssignmentOp()) { 1007 if (asc.alwaysAdd()) { 1008 autoCreateBlock(); 1009 appendStmt(Block, B, asc); 1010 } 1011 Visit(B->getLHS()); 1012 return Visit(B->getRHS()); 1013 } 1014 1015 if (asc.alwaysAdd()) { 1016 autoCreateBlock(); 1017 appendStmt(Block, B, asc); 1018 } 1019 1020 CFGBlock *RBlock = Visit(B->getRHS()); 1021 CFGBlock *LBlock = Visit(B->getLHS()); 1022 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1023 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1024 // return RBlock. Otherwise we'll incorrectly return NULL. 1025 return (LBlock ? LBlock : RBlock); 1026} 1027 1028CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1029 if (asc.alwaysAdd()) { 1030 autoCreateBlock(); 1031 appendStmt(Block, E, asc); 1032 } 1033 return Block; 1034} 1035 1036CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1037 // "break" is a control-flow statement. Thus we stop processing the current 1038 // block. 1039 if (badCFG) 1040 return 0; 1041 1042 // Now create a new block that ends with the break statement. 1043 Block = createBlock(false); 1044 Block->setTerminator(B); 1045 1046 // If there is no target for the break, then we are looking at an incomplete 1047 // AST. This means that the CFG cannot be constructed. 1048 if (BreakJumpTarget.block) { 1049 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1050 addSuccessor(Block, BreakJumpTarget.block); 1051 } else 1052 badCFG = true; 1053 1054 1055 return Block; 1056} 1057 1058static bool CanThrow(Expr *E) { 1059 QualType Ty = E->getType(); 1060 if (Ty->isFunctionPointerType()) 1061 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1062 else if (Ty->isBlockPointerType()) 1063 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1064 1065 const FunctionType *FT = Ty->getAs<FunctionType>(); 1066 if (FT) { 1067 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1068 if (Proto->hasEmptyExceptionSpec()) 1069 return false; 1070 } 1071 return true; 1072} 1073 1074CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1075 // If this is a call to a no-return function, this stops the block here. 1076 bool NoReturn = false; 1077 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 1078 NoReturn = true; 1079 } 1080 1081 bool AddEHEdge = false; 1082 1083 // Languages without exceptions are assumed to not throw. 1084 if (Context->getLangOptions().Exceptions) { 1085 if (BuildOpts.AddEHEdges) 1086 AddEHEdge = true; 1087 } 1088 1089 if (FunctionDecl *FD = C->getDirectCallee()) { 1090 if (FD->hasAttr<NoReturnAttr>()) 1091 NoReturn = true; 1092 if (FD->hasAttr<NoThrowAttr>()) 1093 AddEHEdge = false; 1094 } 1095 1096 if (!CanThrow(C->getCallee())) 1097 AddEHEdge = false; 1098 1099 if (!NoReturn && !AddEHEdge) 1100 return VisitStmt(C, asc.withAlwaysAdd(true)); 1101 1102 if (Block) { 1103 Succ = Block; 1104 if (badCFG) 1105 return 0; 1106 } 1107 1108 Block = createBlock(!NoReturn); 1109 appendStmt(Block, C, asc); 1110 1111 if (NoReturn) { 1112 // Wire this to the exit block directly. 1113 addSuccessor(Block, &cfg->getExit()); 1114 } 1115 if (AddEHEdge) { 1116 // Add exceptional edges. 1117 if (TryTerminatedBlock) 1118 addSuccessor(Block, TryTerminatedBlock); 1119 else 1120 addSuccessor(Block, &cfg->getExit()); 1121 } 1122 1123 return VisitChildren(C); 1124} 1125 1126CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1127 AddStmtChoice asc) { 1128 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1129 appendStmt(ConfluenceBlock, C, asc); 1130 if (badCFG) 1131 return 0; 1132 1133 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1134 Succ = ConfluenceBlock; 1135 Block = NULL; 1136 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1137 if (badCFG) 1138 return 0; 1139 1140 Succ = ConfluenceBlock; 1141 Block = NULL; 1142 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1143 if (badCFG) 1144 return 0; 1145 1146 Block = createBlock(false); 1147 // See if this is a known constant. 1148 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1149 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1150 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1151 Block->setTerminator(C); 1152 return addStmt(C->getCond()); 1153} 1154 1155 1156CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1157 addLocalScopeAndDtors(C); 1158 CFGBlock* LastBlock = Block; 1159 1160 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1161 I != E; ++I ) { 1162 // If we hit a segment of code just containing ';' (NullStmts), we can 1163 // get a null block back. In such cases, just use the LastBlock 1164 if (CFGBlock *newBlock = addStmt(*I)) 1165 LastBlock = newBlock; 1166 1167 if (badCFG) 1168 return NULL; 1169 } 1170 1171 return LastBlock; 1172} 1173 1174CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1175 AddStmtChoice asc) { 1176 // Create the confluence block that will "merge" the results of the ternary 1177 // expression. 1178 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1179 appendStmt(ConfluenceBlock, C, asc); 1180 if (badCFG) 1181 return 0; 1182 1183 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1184 1185 // Create a block for the LHS expression if there is an LHS expression. A 1186 // GCC extension allows LHS to be NULL, causing the condition to be the 1187 // value that is returned instead. 1188 // e.g: x ?: y is shorthand for: x ? x : y; 1189 Succ = ConfluenceBlock; 1190 Block = NULL; 1191 CFGBlock* LHSBlock = NULL; 1192 if (C->getLHS()) { 1193 LHSBlock = Visit(C->getLHS(), alwaysAdd); 1194 if (badCFG) 1195 return 0; 1196 Block = NULL; 1197 } 1198 1199 // Create the block for the RHS expression. 1200 Succ = ConfluenceBlock; 1201 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1202 if (badCFG) 1203 return 0; 1204 1205 // Create the block that will contain the condition. 1206 Block = createBlock(false); 1207 1208 // See if this is a known constant. 1209 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1210 if (LHSBlock) { 1211 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1212 } else { 1213 if (KnownVal.isFalse()) { 1214 // If we know the condition is false, add NULL as the successor for 1215 // the block containing the condition. In this case, the confluence 1216 // block will have just one predecessor. 1217 addSuccessor(Block, 0); 1218 assert(ConfluenceBlock->pred_size() == 1); 1219 } else { 1220 // If we have no LHS expression, add the ConfluenceBlock as a direct 1221 // successor for the block containing the condition. Moreover, we need to 1222 // reverse the order of the predecessors in the ConfluenceBlock because 1223 // the RHSBlock will have been added to the succcessors already, and we 1224 // want the first predecessor to the the block containing the expression 1225 // for the case when the ternary expression evaluates to true. 1226 addSuccessor(Block, ConfluenceBlock); 1227 // Note that there can possibly only be one predecessor if one of the 1228 // subexpressions resulted in calling a noreturn function. 1229 std::reverse(ConfluenceBlock->pred_begin(), 1230 ConfluenceBlock->pred_end()); 1231 } 1232 } 1233 1234 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1235 Block->setTerminator(C); 1236 return addStmt(C->getCond()); 1237} 1238 1239CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1240 if (DS->isSingleDecl()) 1241 return VisitDeclSubExpr(DS); 1242 1243 CFGBlock *B = 0; 1244 1245 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1246 typedef llvm::SmallVector<Decl*,10> BufTy; 1247 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1248 1249 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1250 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1251 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1252 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1253 1254 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1255 // automatically freed with the CFG. 1256 DeclGroupRef DG(*I); 1257 Decl *D = *I; 1258 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1259 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1260 1261 // Append the fake DeclStmt to block. 1262 B = VisitDeclSubExpr(DSNew); 1263 } 1264 1265 return B; 1266} 1267 1268/// VisitDeclSubExpr - Utility method to add block-level expressions for 1269/// DeclStmts and initializers in them. 1270CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1271 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1272 1273 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1274 1275 if (!VD) { 1276 autoCreateBlock(); 1277 appendStmt(Block, DS); 1278 return Block; 1279 } 1280 1281 bool IsReference = false; 1282 bool HasTemporaries = false; 1283 1284 // Destructors of temporaries in initialization expression should be called 1285 // after initialization finishes. 1286 Expr *Init = VD->getInit(); 1287 if (Init) { 1288 IsReference = VD->getType()->isReferenceType(); 1289 HasTemporaries = isa<ExprWithCleanups>(Init); 1290 1291 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1292 // Generate destructors for temporaries in initialization expression. 1293 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1294 IsReference); 1295 } 1296 } 1297 1298 autoCreateBlock(); 1299 appendStmt(Block, DS); 1300 1301 if (Init) { 1302 if (HasTemporaries) 1303 // For expression with temporaries go directly to subexpression to omit 1304 // generating destructors for the second time. 1305 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1306 else 1307 Visit(Init); 1308 } 1309 1310 // If the type of VD is a VLA, then we must process its size expressions. 1311 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1312 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1313 Block = addStmt(VA->getSizeExpr()); 1314 1315 // Remove variable from local scope. 1316 if (ScopePos && VD == *ScopePos) 1317 ++ScopePos; 1318 1319 return Block; 1320} 1321 1322CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1323 // We may see an if statement in the middle of a basic block, or it may be the 1324 // first statement we are processing. In either case, we create a new basic 1325 // block. First, we create the blocks for the then...else statements, and 1326 // then we create the block containing the if statement. If we were in the 1327 // middle of a block, we stop processing that block. That block is then the 1328 // implicit successor for the "then" and "else" clauses. 1329 1330 // Save local scope position because in case of condition variable ScopePos 1331 // won't be restored when traversing AST. 1332 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1333 1334 // Create local scope for possible condition variable. 1335 // Store scope position. Add implicit destructor. 1336 if (VarDecl* VD = I->getConditionVariable()) { 1337 LocalScope::const_iterator BeginScopePos = ScopePos; 1338 addLocalScopeForVarDecl(VD); 1339 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1340 } 1341 1342 // The block we were proccessing is now finished. Make it the successor 1343 // block. 1344 if (Block) { 1345 Succ = Block; 1346 if (badCFG) 1347 return 0; 1348 } 1349 1350 // Process the false branch. 1351 CFGBlock* ElseBlock = Succ; 1352 1353 if (Stmt* Else = I->getElse()) { 1354 SaveAndRestore<CFGBlock*> sv(Succ); 1355 1356 // NULL out Block so that the recursive call to Visit will 1357 // create a new basic block. 1358 Block = NULL; 1359 1360 // If branch is not a compound statement create implicit scope 1361 // and add destructors. 1362 if (!isa<CompoundStmt>(Else)) 1363 addLocalScopeAndDtors(Else); 1364 1365 ElseBlock = addStmt(Else); 1366 1367 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1368 ElseBlock = sv.get(); 1369 else if (Block) { 1370 if (badCFG) 1371 return 0; 1372 } 1373 } 1374 1375 // Process the true branch. 1376 CFGBlock* ThenBlock; 1377 { 1378 Stmt* Then = I->getThen(); 1379 assert(Then); 1380 SaveAndRestore<CFGBlock*> sv(Succ); 1381 Block = NULL; 1382 1383 // If branch is not a compound statement create implicit scope 1384 // and add destructors. 1385 if (!isa<CompoundStmt>(Then)) 1386 addLocalScopeAndDtors(Then); 1387 1388 ThenBlock = addStmt(Then); 1389 1390 if (!ThenBlock) { 1391 // We can reach here if the "then" body has all NullStmts. 1392 // Create an empty block so we can distinguish between true and false 1393 // branches in path-sensitive analyses. 1394 ThenBlock = createBlock(false); 1395 addSuccessor(ThenBlock, sv.get()); 1396 } else if (Block) { 1397 if (badCFG) 1398 return 0; 1399 } 1400 } 1401 1402 // Now create a new block containing the if statement. 1403 Block = createBlock(false); 1404 1405 // Set the terminator of the new block to the If statement. 1406 Block->setTerminator(I); 1407 1408 // See if this is a known constant. 1409 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1410 1411 // Now add the successors. 1412 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1413 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1414 1415 // Add the condition as the last statement in the new block. This may create 1416 // new blocks as the condition may contain control-flow. Any newly created 1417 // blocks will be pointed to be "Block". 1418 Block = addStmt(I->getCond()); 1419 1420 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1421 // and the condition variable initialization to the CFG. 1422 if (VarDecl *VD = I->getConditionVariable()) { 1423 if (Expr *Init = VD->getInit()) { 1424 autoCreateBlock(); 1425 appendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1426 addStmt(Init); 1427 } 1428 } 1429 1430 return Block; 1431} 1432 1433 1434CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1435 // If we were in the middle of a block we stop processing that block. 1436 // 1437 // NOTE: If a "return" appears in the middle of a block, this means that the 1438 // code afterwards is DEAD (unreachable). We still keep a basic block 1439 // for that code; a simple "mark-and-sweep" from the entry block will be 1440 // able to report such dead blocks. 1441 1442 // Create the new block. 1443 Block = createBlock(false); 1444 1445 // The Exit block is the only successor. 1446 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1447 addSuccessor(Block, &cfg->getExit()); 1448 1449 // Add the return statement to the block. This may create new blocks if R 1450 // contains control-flow (short-circuit operations). 1451 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1452} 1453 1454CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1455 // Get the block of the labeled statement. Add it to our map. 1456 addStmt(L->getSubStmt()); 1457 CFGBlock* LabelBlock = Block; 1458 1459 if (!LabelBlock) // This can happen when the body is empty, i.e. 1460 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1461 1462 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1463 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1464 1465 // Labels partition blocks, so this is the end of the basic block we were 1466 // processing (L is the block's label). Because this is label (and we have 1467 // already processed the substatement) there is no extra control-flow to worry 1468 // about. 1469 LabelBlock->setLabel(L); 1470 if (badCFG) 1471 return 0; 1472 1473 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1474 Block = NULL; 1475 1476 // This block is now the implicit successor of other blocks. 1477 Succ = LabelBlock; 1478 1479 return LabelBlock; 1480} 1481 1482CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1483 // Goto is a control-flow statement. Thus we stop processing the current 1484 // block and create a new one. 1485 1486 Block = createBlock(false); 1487 Block->setTerminator(G); 1488 1489 // If we already know the mapping to the label block add the successor now. 1490 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1491 1492 if (I == LabelMap.end()) 1493 // We will need to backpatch this block later. 1494 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1495 else { 1496 JumpTarget JT = I->second; 1497 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1498 addSuccessor(Block, JT.block); 1499 } 1500 1501 return Block; 1502} 1503 1504CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1505 CFGBlock* LoopSuccessor = NULL; 1506 1507 // Save local scope position because in case of condition variable ScopePos 1508 // won't be restored when traversing AST. 1509 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1510 1511 // Create local scope for init statement and possible condition variable. 1512 // Add destructor for init statement and condition variable. 1513 // Store scope position for continue statement. 1514 if (Stmt* Init = F->getInit()) 1515 addLocalScopeForStmt(Init); 1516 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1517 1518 if (VarDecl* VD = F->getConditionVariable()) 1519 addLocalScopeForVarDecl(VD); 1520 LocalScope::const_iterator ContinueScopePos = ScopePos; 1521 1522 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1523 1524 // "for" is a control-flow statement. Thus we stop processing the current 1525 // block. 1526 if (Block) { 1527 if (badCFG) 1528 return 0; 1529 LoopSuccessor = Block; 1530 } else 1531 LoopSuccessor = Succ; 1532 1533 // Save the current value for the break targets. 1534 // All breaks should go to the code following the loop. 1535 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1536 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1537 1538 // Because of short-circuit evaluation, the condition of the loop can span 1539 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1540 // evaluate the condition. 1541 CFGBlock* ExitConditionBlock = createBlock(false); 1542 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1543 1544 // Set the terminator for the "exit" condition block. 1545 ExitConditionBlock->setTerminator(F); 1546 1547 // Now add the actual condition to the condition block. Because the condition 1548 // itself may contain control-flow, new blocks may be created. 1549 if (Stmt* C = F->getCond()) { 1550 Block = ExitConditionBlock; 1551 EntryConditionBlock = addStmt(C); 1552 if (badCFG) 1553 return 0; 1554 assert(Block == EntryConditionBlock || 1555 (Block == 0 && EntryConditionBlock == Succ)); 1556 1557 // If this block contains a condition variable, add both the condition 1558 // variable and initializer to the CFG. 1559 if (VarDecl *VD = F->getConditionVariable()) { 1560 if (Expr *Init = VD->getInit()) { 1561 autoCreateBlock(); 1562 appendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1563 EntryConditionBlock = addStmt(Init); 1564 assert(Block == EntryConditionBlock); 1565 } 1566 } 1567 1568 if (Block) { 1569 if (badCFG) 1570 return 0; 1571 } 1572 } 1573 1574 // The condition block is the implicit successor for the loop body as well as 1575 // any code above the loop. 1576 Succ = EntryConditionBlock; 1577 1578 // See if this is a known constant. 1579 TryResult KnownVal(true); 1580 1581 if (F->getCond()) 1582 KnownVal = tryEvaluateBool(F->getCond()); 1583 1584 // Now create the loop body. 1585 { 1586 assert(F->getBody()); 1587 1588 // Save the current values for Block, Succ, and continue targets. 1589 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1590 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1591 1592 // Create a new block to contain the (bottom) of the loop body. 1593 Block = NULL; 1594 1595 // Loop body should end with destructor of Condition variable (if any). 1596 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1597 1598 if (Stmt* I = F->getInc()) { 1599 // Generate increment code in its own basic block. This is the target of 1600 // continue statements. 1601 Succ = addStmt(I); 1602 } else { 1603 // No increment code. Create a special, empty, block that is used as the 1604 // target block for "looping back" to the start of the loop. 1605 assert(Succ == EntryConditionBlock); 1606 Succ = Block ? Block : createBlock(); 1607 } 1608 1609 // Finish up the increment (or empty) block if it hasn't been already. 1610 if (Block) { 1611 assert(Block == Succ); 1612 if (badCFG) 1613 return 0; 1614 Block = 0; 1615 } 1616 1617 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1618 1619 // The starting block for the loop increment is the block that should 1620 // represent the 'loop target' for looping back to the start of the loop. 1621 ContinueJumpTarget.block->setLoopTarget(F); 1622 1623 // If body is not a compound statement create implicit scope 1624 // and add destructors. 1625 if (!isa<CompoundStmt>(F->getBody())) 1626 addLocalScopeAndDtors(F->getBody()); 1627 1628 // Now populate the body block, and in the process create new blocks as we 1629 // walk the body of the loop. 1630 CFGBlock* BodyBlock = addStmt(F->getBody()); 1631 1632 if (!BodyBlock) 1633 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1634 else if (badCFG) 1635 return 0; 1636 1637 // This new body block is a successor to our "exit" condition block. 1638 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1639 } 1640 1641 // Link up the condition block with the code that follows the loop. (the 1642 // false branch). 1643 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1644 1645 // If the loop contains initialization, create a new block for those 1646 // statements. This block can also contain statements that precede the loop. 1647 if (Stmt* I = F->getInit()) { 1648 Block = createBlock(); 1649 return addStmt(I); 1650 } 1651 1652 // There is no loop initialization. We are thus basically a while loop. 1653 // NULL out Block to force lazy block construction. 1654 Block = NULL; 1655 Succ = EntryConditionBlock; 1656 return EntryConditionBlock; 1657} 1658 1659CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1660 if (asc.alwaysAdd()) { 1661 autoCreateBlock(); 1662 appendStmt(Block, M, asc); 1663 } 1664 return Visit(M->getBase()); 1665} 1666 1667CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1668 // Objective-C fast enumeration 'for' statements: 1669 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1670 // 1671 // for ( Type newVariable in collection_expression ) { statements } 1672 // 1673 // becomes: 1674 // 1675 // prologue: 1676 // 1. collection_expression 1677 // T. jump to loop_entry 1678 // loop_entry: 1679 // 1. side-effects of element expression 1680 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1681 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1682 // TB: 1683 // statements 1684 // T. jump to loop_entry 1685 // FB: 1686 // what comes after 1687 // 1688 // and 1689 // 1690 // Type existingItem; 1691 // for ( existingItem in expression ) { statements } 1692 // 1693 // becomes: 1694 // 1695 // the same with newVariable replaced with existingItem; the binding works 1696 // the same except that for one ObjCForCollectionStmt::getElement() returns 1697 // a DeclStmt and the other returns a DeclRefExpr. 1698 // 1699 1700 CFGBlock* LoopSuccessor = 0; 1701 1702 if (Block) { 1703 if (badCFG) 1704 return 0; 1705 LoopSuccessor = Block; 1706 Block = 0; 1707 } else 1708 LoopSuccessor = Succ; 1709 1710 // Build the condition blocks. 1711 CFGBlock* ExitConditionBlock = createBlock(false); 1712 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1713 1714 // Set the terminator for the "exit" condition block. 1715 ExitConditionBlock->setTerminator(S); 1716 1717 // The last statement in the block should be the ObjCForCollectionStmt, which 1718 // performs the actual binding to 'element' and determines if there are any 1719 // more items in the collection. 1720 appendStmt(ExitConditionBlock, S); 1721 Block = ExitConditionBlock; 1722 1723 // Walk the 'element' expression to see if there are any side-effects. We 1724 // generate new blocks as necesary. We DON'T add the statement by default to 1725 // the CFG unless it contains control-flow. 1726 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1727 if (Block) { 1728 if (badCFG) 1729 return 0; 1730 Block = 0; 1731 } 1732 1733 // The condition block is the implicit successor for the loop body as well as 1734 // any code above the loop. 1735 Succ = EntryConditionBlock; 1736 1737 // Now create the true branch. 1738 { 1739 // Save the current values for Succ, continue and break targets. 1740 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1741 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1742 save_break(BreakJumpTarget); 1743 1744 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1745 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1746 1747 CFGBlock* BodyBlock = addStmt(S->getBody()); 1748 1749 if (!BodyBlock) 1750 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1751 else if (Block) { 1752 if (badCFG) 1753 return 0; 1754 } 1755 1756 // This new body block is a successor to our "exit" condition block. 1757 addSuccessor(ExitConditionBlock, BodyBlock); 1758 } 1759 1760 // Link up the condition block with the code that follows the loop. 1761 // (the false branch). 1762 addSuccessor(ExitConditionBlock, LoopSuccessor); 1763 1764 // Now create a prologue block to contain the collection expression. 1765 Block = createBlock(); 1766 return addStmt(S->getCollection()); 1767} 1768 1769CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1770 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1771 1772 // Inline the body. 1773 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1774 1775 // The sync body starts its own basic block. This makes it a little easier 1776 // for diagnostic clients. 1777 if (SyncBlock) { 1778 if (badCFG) 1779 return 0; 1780 1781 Block = 0; 1782 Succ = SyncBlock; 1783 } 1784 1785 // Add the @synchronized to the CFG. 1786 autoCreateBlock(); 1787 appendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1788 1789 // Inline the sync expression. 1790 return addStmt(S->getSynchExpr()); 1791} 1792 1793CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1794 // FIXME 1795 return NYS(); 1796} 1797 1798CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1799 CFGBlock* LoopSuccessor = NULL; 1800 1801 // Save local scope position because in case of condition variable ScopePos 1802 // won't be restored when traversing AST. 1803 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1804 1805 // Create local scope for possible condition variable. 1806 // Store scope position for continue statement. 1807 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1808 if (VarDecl* VD = W->getConditionVariable()) { 1809 addLocalScopeForVarDecl(VD); 1810 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1811 } 1812 1813 // "while" is a control-flow statement. Thus we stop processing the current 1814 // block. 1815 if (Block) { 1816 if (badCFG) 1817 return 0; 1818 LoopSuccessor = Block; 1819 } else 1820 LoopSuccessor = Succ; 1821 1822 // Because of short-circuit evaluation, the condition of the loop can span 1823 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1824 // evaluate the condition. 1825 CFGBlock* ExitConditionBlock = createBlock(false); 1826 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1827 1828 // Set the terminator for the "exit" condition block. 1829 ExitConditionBlock->setTerminator(W); 1830 1831 // Now add the actual condition to the condition block. Because the condition 1832 // itself may contain control-flow, new blocks may be created. Thus we update 1833 // "Succ" after adding the condition. 1834 if (Stmt* C = W->getCond()) { 1835 Block = ExitConditionBlock; 1836 EntryConditionBlock = addStmt(C); 1837 // The condition might finish the current 'Block'. 1838 Block = EntryConditionBlock; 1839 1840 // If this block contains a condition variable, add both the condition 1841 // variable and initializer to the CFG. 1842 if (VarDecl *VD = W->getConditionVariable()) { 1843 if (Expr *Init = VD->getInit()) { 1844 autoCreateBlock(); 1845 appendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1846 EntryConditionBlock = addStmt(Init); 1847 assert(Block == EntryConditionBlock); 1848 } 1849 } 1850 1851 if (Block) { 1852 if (badCFG) 1853 return 0; 1854 } 1855 } 1856 1857 // The condition block is the implicit successor for the loop body as well as 1858 // any code above the loop. 1859 Succ = EntryConditionBlock; 1860 1861 // See if this is a known constant. 1862 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1863 1864 // Process the loop body. 1865 { 1866 assert(W->getBody()); 1867 1868 // Save the current values for Block, Succ, and continue and break targets 1869 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1870 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1871 save_break(BreakJumpTarget); 1872 1873 // Create an empty block to represent the transition block for looping back 1874 // to the head of the loop. 1875 Block = 0; 1876 assert(Succ == EntryConditionBlock); 1877 Succ = createBlock(); 1878 Succ->setLoopTarget(W); 1879 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1880 1881 // All breaks should go to the code following the loop. 1882 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1883 1884 // NULL out Block to force lazy instantiation of blocks for the body. 1885 Block = NULL; 1886 1887 // Loop body should end with destructor of Condition variable (if any). 1888 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1889 1890 // If body is not a compound statement create implicit scope 1891 // and add destructors. 1892 if (!isa<CompoundStmt>(W->getBody())) 1893 addLocalScopeAndDtors(W->getBody()); 1894 1895 // Create the body. The returned block is the entry to the loop body. 1896 CFGBlock* BodyBlock = addStmt(W->getBody()); 1897 1898 if (!BodyBlock) 1899 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 1900 else if (Block) { 1901 if (badCFG) 1902 return 0; 1903 } 1904 1905 // Add the loop body entry as a successor to the condition. 1906 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1907 } 1908 1909 // Link up the condition block with the code that follows the loop. (the 1910 // false branch). 1911 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1912 1913 // There can be no more statements in the condition block since we loop back 1914 // to this block. NULL out Block to force lazy creation of another block. 1915 Block = NULL; 1916 1917 // Return the condition block, which is the dominating block for the loop. 1918 Succ = EntryConditionBlock; 1919 return EntryConditionBlock; 1920} 1921 1922 1923CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1924 // FIXME: For now we pretend that @catch and the code it contains does not 1925 // exit. 1926 return Block; 1927} 1928 1929CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1930 // FIXME: This isn't complete. We basically treat @throw like a return 1931 // statement. 1932 1933 // If we were in the middle of a block we stop processing that block. 1934 if (badCFG) 1935 return 0; 1936 1937 // Create the new block. 1938 Block = createBlock(false); 1939 1940 // The Exit block is the only successor. 1941 addSuccessor(Block, &cfg->getExit()); 1942 1943 // Add the statement to the block. This may create new blocks if S contains 1944 // control-flow (short-circuit operations). 1945 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1946} 1947 1948CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1949 // If we were in the middle of a block we stop processing that block. 1950 if (badCFG) 1951 return 0; 1952 1953 // Create the new block. 1954 Block = createBlock(false); 1955 1956 if (TryTerminatedBlock) 1957 // The current try statement is the only successor. 1958 addSuccessor(Block, TryTerminatedBlock); 1959 else 1960 // otherwise the Exit block is the only successor. 1961 addSuccessor(Block, &cfg->getExit()); 1962 1963 // Add the statement to the block. This may create new blocks if S contains 1964 // control-flow (short-circuit operations). 1965 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1966} 1967 1968CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1969 CFGBlock* LoopSuccessor = NULL; 1970 1971 // "do...while" is a control-flow statement. Thus we stop processing the 1972 // current block. 1973 if (Block) { 1974 if (badCFG) 1975 return 0; 1976 LoopSuccessor = Block; 1977 } else 1978 LoopSuccessor = Succ; 1979 1980 // Because of short-circuit evaluation, the condition of the loop can span 1981 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1982 // evaluate the condition. 1983 CFGBlock* ExitConditionBlock = createBlock(false); 1984 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1985 1986 // Set the terminator for the "exit" condition block. 1987 ExitConditionBlock->setTerminator(D); 1988 1989 // Now add the actual condition to the condition block. Because the condition 1990 // itself may contain control-flow, new blocks may be created. 1991 if (Stmt* C = D->getCond()) { 1992 Block = ExitConditionBlock; 1993 EntryConditionBlock = addStmt(C); 1994 if (Block) { 1995 if (badCFG) 1996 return 0; 1997 } 1998 } 1999 2000 // The condition block is the implicit successor for the loop body. 2001 Succ = EntryConditionBlock; 2002 2003 // See if this is a known constant. 2004 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2005 2006 // Process the loop body. 2007 CFGBlock* BodyBlock = NULL; 2008 { 2009 assert(D->getBody()); 2010 2011 // Save the current values for Block, Succ, and continue and break targets 2012 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2013 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2014 save_break(BreakJumpTarget); 2015 2016 // All continues within this loop should go to the condition block 2017 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2018 2019 // All breaks should go to the code following the loop. 2020 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2021 2022 // NULL out Block to force lazy instantiation of blocks for the body. 2023 Block = NULL; 2024 2025 // If body is not a compound statement create implicit scope 2026 // and add destructors. 2027 if (!isa<CompoundStmt>(D->getBody())) 2028 addLocalScopeAndDtors(D->getBody()); 2029 2030 // Create the body. The returned block is the entry to the loop body. 2031 BodyBlock = addStmt(D->getBody()); 2032 2033 if (!BodyBlock) 2034 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2035 else if (Block) { 2036 if (badCFG) 2037 return 0; 2038 } 2039 2040 if (!KnownVal.isFalse()) { 2041 // Add an intermediate block between the BodyBlock and the 2042 // ExitConditionBlock to represent the "loop back" transition. Create an 2043 // empty block to represent the transition block for looping back to the 2044 // head of the loop. 2045 // FIXME: Can we do this more efficiently without adding another block? 2046 Block = NULL; 2047 Succ = BodyBlock; 2048 CFGBlock *LoopBackBlock = createBlock(); 2049 LoopBackBlock->setLoopTarget(D); 2050 2051 // Add the loop body entry as a successor to the condition. 2052 addSuccessor(ExitConditionBlock, LoopBackBlock); 2053 } 2054 else 2055 addSuccessor(ExitConditionBlock, NULL); 2056 } 2057 2058 // Link up the condition block with the code that follows the loop. 2059 // (the false branch). 2060 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2061 2062 // There can be no more statements in the body block(s) since we loop back to 2063 // the body. NULL out Block to force lazy creation of another block. 2064 Block = NULL; 2065 2066 // Return the loop body, which is the dominating block for the loop. 2067 Succ = BodyBlock; 2068 return BodyBlock; 2069} 2070 2071CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2072 // "continue" is a control-flow statement. Thus we stop processing the 2073 // current block. 2074 if (badCFG) 2075 return 0; 2076 2077 // Now create a new block that ends with the continue statement. 2078 Block = createBlock(false); 2079 Block->setTerminator(C); 2080 2081 // If there is no target for the continue, then we are looking at an 2082 // incomplete AST. This means the CFG cannot be constructed. 2083 if (ContinueJumpTarget.block) { 2084 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2085 addSuccessor(Block, ContinueJumpTarget.block); 2086 } else 2087 badCFG = true; 2088 2089 return Block; 2090} 2091 2092CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 2093 AddStmtChoice asc) { 2094 2095 if (asc.alwaysAdd()) { 2096 autoCreateBlock(); 2097 appendStmt(Block, E); 2098 } 2099 2100 // VLA types have expressions that must be evaluated. 2101 if (E->isArgumentType()) { 2102 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2103 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2104 addStmt(VA->getSizeExpr()); 2105 } 2106 2107 return Block; 2108} 2109 2110/// VisitStmtExpr - Utility method to handle (nested) statement 2111/// expressions (a GCC extension). 2112CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2113 if (asc.alwaysAdd()) { 2114 autoCreateBlock(); 2115 appendStmt(Block, SE); 2116 } 2117 return VisitCompoundStmt(SE->getSubStmt()); 2118} 2119 2120CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2121 // "switch" is a control-flow statement. Thus we stop processing the current 2122 // block. 2123 CFGBlock* SwitchSuccessor = NULL; 2124 2125 // Save local scope position because in case of condition variable ScopePos 2126 // won't be restored when traversing AST. 2127 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2128 2129 // Create local scope for possible condition variable. 2130 // Store scope position. Add implicit destructor. 2131 if (VarDecl* VD = Terminator->getConditionVariable()) { 2132 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2133 addLocalScopeForVarDecl(VD); 2134 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2135 } 2136 2137 if (Block) { 2138 if (badCFG) 2139 return 0; 2140 SwitchSuccessor = Block; 2141 } else SwitchSuccessor = Succ; 2142 2143 // Save the current "switch" context. 2144 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2145 save_default(DefaultCaseBlock); 2146 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2147 2148 // Set the "default" case to be the block after the switch statement. If the 2149 // switch statement contains a "default:", this value will be overwritten with 2150 // the block for that code. 2151 DefaultCaseBlock = SwitchSuccessor; 2152 2153 // Create a new block that will contain the switch statement. 2154 SwitchTerminatedBlock = createBlock(false); 2155 2156 // Now process the switch body. The code after the switch is the implicit 2157 // successor. 2158 Succ = SwitchSuccessor; 2159 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2160 2161 // When visiting the body, the case statements should automatically get linked 2162 // up to the switch. We also don't keep a pointer to the body, since all 2163 // control-flow from the switch goes to case/default statements. 2164 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2165 Block = NULL; 2166 2167 // If body is not a compound statement create implicit scope 2168 // and add destructors. 2169 if (!isa<CompoundStmt>(Terminator->getBody())) 2170 addLocalScopeAndDtors(Terminator->getBody()); 2171 2172 addStmt(Terminator->getBody()); 2173 if (Block) { 2174 if (badCFG) 2175 return 0; 2176 } 2177 2178 // If we have no "default:" case, the default transition is to the code 2179 // following the switch body. 2180 addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2181 2182 // Add the terminator and condition in the switch block. 2183 SwitchTerminatedBlock->setTerminator(Terminator); 2184 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2185 Block = SwitchTerminatedBlock; 2186 Block = addStmt(Terminator->getCond()); 2187 2188 // Finally, if the SwitchStmt contains a condition variable, add both the 2189 // SwitchStmt and the condition variable initialization to the CFG. 2190 if (VarDecl *VD = Terminator->getConditionVariable()) { 2191 if (Expr *Init = VD->getInit()) { 2192 autoCreateBlock(); 2193 appendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2194 addStmt(Init); 2195 } 2196 } 2197 2198 return Block; 2199} 2200 2201CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2202 // CaseStmts are essentially labels, so they are the first statement in a 2203 // block. 2204 CFGBlock *TopBlock = 0, *LastBlock = 0; 2205 2206 if (Stmt *Sub = CS->getSubStmt()) { 2207 // For deeply nested chains of CaseStmts, instead of doing a recursion 2208 // (which can blow out the stack), manually unroll and create blocks 2209 // along the way. 2210 while (isa<CaseStmt>(Sub)) { 2211 CFGBlock *currentBlock = createBlock(false); 2212 currentBlock->setLabel(CS); 2213 2214 if (TopBlock) 2215 addSuccessor(LastBlock, currentBlock); 2216 else 2217 TopBlock = currentBlock; 2218 2219 addSuccessor(SwitchTerminatedBlock, currentBlock); 2220 LastBlock = currentBlock; 2221 2222 CS = cast<CaseStmt>(Sub); 2223 Sub = CS->getSubStmt(); 2224 } 2225 2226 addStmt(Sub); 2227 } 2228 2229 CFGBlock* CaseBlock = Block; 2230 if (!CaseBlock) 2231 CaseBlock = createBlock(); 2232 2233 // Cases statements partition blocks, so this is the top of the basic block we 2234 // were processing (the "case XXX:" is the label). 2235 CaseBlock->setLabel(CS); 2236 2237 if (badCFG) 2238 return 0; 2239 2240 // Add this block to the list of successors for the block with the switch 2241 // statement. 2242 assert(SwitchTerminatedBlock); 2243 addSuccessor(SwitchTerminatedBlock, CaseBlock); 2244 2245 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2246 Block = NULL; 2247 2248 if (TopBlock) { 2249 addSuccessor(LastBlock, CaseBlock); 2250 Succ = TopBlock; 2251 } else { 2252 // This block is now the implicit successor of other blocks. 2253 Succ = CaseBlock; 2254 } 2255 2256 return Succ; 2257} 2258 2259CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2260 if (Terminator->getSubStmt()) 2261 addStmt(Terminator->getSubStmt()); 2262 2263 DefaultCaseBlock = Block; 2264 2265 if (!DefaultCaseBlock) 2266 DefaultCaseBlock = createBlock(); 2267 2268 // Default statements partition blocks, so this is the top of the basic block 2269 // we were processing (the "default:" is the label). 2270 DefaultCaseBlock->setLabel(Terminator); 2271 2272 if (badCFG) 2273 return 0; 2274 2275 // Unlike case statements, we don't add the default block to the successors 2276 // for the switch statement immediately. This is done when we finish 2277 // processing the switch statement. This allows for the default case 2278 // (including a fall-through to the code after the switch statement) to always 2279 // be the last successor of a switch-terminated block. 2280 2281 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2282 Block = NULL; 2283 2284 // This block is now the implicit successor of other blocks. 2285 Succ = DefaultCaseBlock; 2286 2287 return DefaultCaseBlock; 2288} 2289 2290CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2291 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2292 // current block. 2293 CFGBlock* TrySuccessor = NULL; 2294 2295 if (Block) { 2296 if (badCFG) 2297 return 0; 2298 TrySuccessor = Block; 2299 } else TrySuccessor = Succ; 2300 2301 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2302 2303 // Create a new block that will contain the try statement. 2304 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2305 // Add the terminator in the try block. 2306 NewTryTerminatedBlock->setTerminator(Terminator); 2307 2308 bool HasCatchAll = false; 2309 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2310 // The code after the try is the implicit successor. 2311 Succ = TrySuccessor; 2312 CXXCatchStmt *CS = Terminator->getHandler(h); 2313 if (CS->getExceptionDecl() == 0) { 2314 HasCatchAll = true; 2315 } 2316 Block = NULL; 2317 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2318 if (CatchBlock == 0) 2319 return 0; 2320 // Add this block to the list of successors for the block with the try 2321 // statement. 2322 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2323 } 2324 if (!HasCatchAll) { 2325 if (PrevTryTerminatedBlock) 2326 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2327 else 2328 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2329 } 2330 2331 // The code after the try is the implicit successor. 2332 Succ = TrySuccessor; 2333 2334 // Save the current "try" context. 2335 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2336 TryTerminatedBlock = NewTryTerminatedBlock; 2337 2338 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2339 Block = NULL; 2340 Block = addStmt(Terminator->getTryBlock()); 2341 return Block; 2342} 2343 2344CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2345 // CXXCatchStmt are treated like labels, so they are the first statement in a 2346 // block. 2347 2348 // Save local scope position because in case of exception variable ScopePos 2349 // won't be restored when traversing AST. 2350 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2351 2352 // Create local scope for possible exception variable. 2353 // Store scope position. Add implicit destructor. 2354 if (VarDecl* VD = CS->getExceptionDecl()) { 2355 LocalScope::const_iterator BeginScopePos = ScopePos; 2356 addLocalScopeForVarDecl(VD); 2357 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2358 } 2359 2360 if (CS->getHandlerBlock()) 2361 addStmt(CS->getHandlerBlock()); 2362 2363 CFGBlock* CatchBlock = Block; 2364 if (!CatchBlock) 2365 CatchBlock = createBlock(); 2366 2367 CatchBlock->setLabel(CS); 2368 2369 if (badCFG) 2370 return 0; 2371 2372 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2373 Block = NULL; 2374 2375 return CatchBlock; 2376} 2377 2378CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2379 AddStmtChoice asc) { 2380 if (BuildOpts.AddImplicitDtors) { 2381 // If adding implicit destructors visit the full expression for adding 2382 // destructors of temporaries. 2383 VisitForTemporaryDtors(E->getSubExpr()); 2384 2385 // Full expression has to be added as CFGStmt so it will be sequenced 2386 // before destructors of it's temporaries. 2387 asc = asc.withAlwaysAdd(true); 2388 } 2389 return Visit(E->getSubExpr(), asc); 2390} 2391 2392CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2393 AddStmtChoice asc) { 2394 if (asc.alwaysAdd()) { 2395 autoCreateBlock(); 2396 appendStmt(Block, E, asc); 2397 2398 // We do not want to propagate the AlwaysAdd property. 2399 asc = asc.withAlwaysAdd(false); 2400 } 2401 return Visit(E->getSubExpr(), asc); 2402} 2403 2404CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2405 AddStmtChoice asc) { 2406 autoCreateBlock(); 2407 if (!C->isElidable()) 2408 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2409 2410 return VisitChildren(C); 2411} 2412 2413CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2414 AddStmtChoice asc) { 2415 if (asc.alwaysAdd()) { 2416 autoCreateBlock(); 2417 appendStmt(Block, E, asc); 2418 // We do not want to propagate the AlwaysAdd property. 2419 asc = asc.withAlwaysAdd(false); 2420 } 2421 return Visit(E->getSubExpr(), asc); 2422} 2423 2424CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2425 AddStmtChoice asc) { 2426 autoCreateBlock(); 2427 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2428 return VisitChildren(C); 2429} 2430 2431CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2432 AddStmtChoice asc) { 2433 autoCreateBlock(); 2434 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2435 return VisitChildren(C); 2436} 2437 2438CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2439 AddStmtChoice asc) { 2440 if (asc.alwaysAdd()) { 2441 autoCreateBlock(); 2442 appendStmt(Block, E, asc); 2443 } 2444 return Visit(E->getSubExpr(), AddStmtChoice()); 2445} 2446 2447CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2448 // Lazily create the indirect-goto dispatch block if there isn't one already. 2449 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2450 2451 if (!IBlock) { 2452 IBlock = createBlock(false); 2453 cfg->setIndirectGotoBlock(IBlock); 2454 } 2455 2456 // IndirectGoto is a control-flow statement. Thus we stop processing the 2457 // current block and create a new one. 2458 if (badCFG) 2459 return 0; 2460 2461 Block = createBlock(false); 2462 Block->setTerminator(I); 2463 addSuccessor(Block, IBlock); 2464 return addStmt(I->getTarget()); 2465} 2466 2467CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2468tryAgain: 2469 if (!E) { 2470 badCFG = true; 2471 return NULL; 2472 } 2473 switch (E->getStmtClass()) { 2474 default: 2475 return VisitChildrenForTemporaryDtors(E); 2476 2477 case Stmt::BinaryOperatorClass: 2478 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2479 2480 case Stmt::CXXBindTemporaryExprClass: 2481 return VisitCXXBindTemporaryExprForTemporaryDtors( 2482 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2483 2484 case Stmt::ConditionalOperatorClass: 2485 return VisitConditionalOperatorForTemporaryDtors( 2486 cast<ConditionalOperator>(E), BindToTemporary); 2487 2488 case Stmt::ImplicitCastExprClass: 2489 // For implicit cast we want BindToTemporary to be passed further. 2490 E = cast<CastExpr>(E)->getSubExpr(); 2491 goto tryAgain; 2492 2493 case Stmt::ParenExprClass: 2494 E = cast<ParenExpr>(E)->getSubExpr(); 2495 goto tryAgain; 2496 } 2497} 2498 2499CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2500 // When visiting children for destructors we want to visit them in reverse 2501 // order. Because there's no reverse iterator for children must to reverse 2502 // them in helper vector. 2503 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2504 ChildrenVect ChildrenRev; 2505 for (Stmt::child_range I = E->children(); I; ++I) { 2506 if (*I) ChildrenRev.push_back(*I); 2507 } 2508 2509 CFGBlock *B = Block; 2510 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2511 L = ChildrenRev.rend(); I != L; ++I) { 2512 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2513 B = R; 2514 } 2515 return B; 2516} 2517 2518CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2519 if (E->isLogicalOp()) { 2520 // Destructors for temporaries in LHS expression should be called after 2521 // those for RHS expression. Even if this will unnecessarily create a block, 2522 // this block will be used at least by the full expression. 2523 autoCreateBlock(); 2524 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2525 if (badCFG) 2526 return NULL; 2527 2528 Succ = ConfluenceBlock; 2529 Block = NULL; 2530 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2531 2532 if (RHSBlock) { 2533 if (badCFG) 2534 return NULL; 2535 2536 // If RHS expression did produce destructors we need to connect created 2537 // blocks to CFG in same manner as for binary operator itself. 2538 CFGBlock *LHSBlock = createBlock(false); 2539 LHSBlock->setTerminator(CFGTerminator(E, true)); 2540 2541 // For binary operator LHS block is before RHS in list of predecessors 2542 // of ConfluenceBlock. 2543 std::reverse(ConfluenceBlock->pred_begin(), 2544 ConfluenceBlock->pred_end()); 2545 2546 // See if this is a known constant. 2547 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2548 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2549 KnownVal.negate(); 2550 2551 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2552 // itself. 2553 if (E->getOpcode() == BO_LOr) { 2554 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2555 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2556 } else { 2557 assert (E->getOpcode() == BO_LAnd); 2558 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2559 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2560 } 2561 2562 Block = LHSBlock; 2563 return LHSBlock; 2564 } 2565 2566 Block = ConfluenceBlock; 2567 return ConfluenceBlock; 2568 } 2569 2570 if (E->isAssignmentOp()) { 2571 // For assignment operator (=) LHS expression is visited 2572 // before RHS expression. For destructors visit them in reverse order. 2573 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2574 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2575 return LHSBlock ? LHSBlock : RHSBlock; 2576 } 2577 2578 // For any other binary operator RHS expression is visited before 2579 // LHS expression (order of children). For destructors visit them in reverse 2580 // order. 2581 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2582 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2583 return RHSBlock ? RHSBlock : LHSBlock; 2584} 2585 2586CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2587 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2588 // First add destructors for temporaries in subexpression. 2589 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2590 if (!BindToTemporary) { 2591 // If lifetime of temporary is not prolonged (by assigning to constant 2592 // reference) add destructor for it. 2593 autoCreateBlock(); 2594 appendTemporaryDtor(Block, E); 2595 B = Block; 2596 } 2597 return B; 2598} 2599 2600CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2601 ConditionalOperator *E, bool BindToTemporary) { 2602 // First add destructors for condition expression. Even if this will 2603 // unnecessarily create a block, this block will be used at least by the full 2604 // expression. 2605 autoCreateBlock(); 2606 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2607 if (badCFG) 2608 return NULL; 2609 2610 // Try to add block with destructors for LHS expression. 2611 CFGBlock *LHSBlock = NULL; 2612 if (E->getLHS()) { 2613 Succ = ConfluenceBlock; 2614 Block = NULL; 2615 LHSBlock = VisitForTemporaryDtors(E->getLHS(), BindToTemporary); 2616 if (badCFG) 2617 return NULL; 2618 } 2619 2620 // Try to add block with destructors for RHS expression; 2621 Succ = ConfluenceBlock; 2622 Block = NULL; 2623 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS(), BindToTemporary); 2624 if (badCFG) 2625 return NULL; 2626 2627 if (!RHSBlock && !LHSBlock) { 2628 // If neither LHS nor RHS expression had temporaries to destroy don't create 2629 // more blocks. 2630 Block = ConfluenceBlock; 2631 return Block; 2632 } 2633 2634 Block = createBlock(false); 2635 Block->setTerminator(CFGTerminator(E, true)); 2636 2637 // See if this is a known constant. 2638 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2639 2640 if (LHSBlock) { 2641 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2642 } else if (KnownVal.isFalse()) { 2643 addSuccessor(Block, NULL); 2644 } else { 2645 addSuccessor(Block, ConfluenceBlock); 2646 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2647 } 2648 2649 if (!RHSBlock) 2650 RHSBlock = ConfluenceBlock; 2651 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2652 2653 return Block; 2654} 2655 2656} // end anonymous namespace 2657 2658/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2659/// no successors or predecessors. If this is the first block created in the 2660/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2661CFGBlock* CFG::createBlock() { 2662 bool first_block = begin() == end(); 2663 2664 // Create the block. 2665 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2666 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2667 Blocks.push_back(Mem, BlkBVC); 2668 2669 // If this is the first block, set it as the Entry and Exit. 2670 if (first_block) 2671 Entry = Exit = &back(); 2672 2673 // Return the block. 2674 return &back(); 2675} 2676 2677/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2678/// CFG is returned to the caller. 2679CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2680 BuildOptions BO) { 2681 CFGBuilder Builder; 2682 return Builder.buildCFG(D, Statement, C, BO); 2683} 2684 2685//===----------------------------------------------------------------------===// 2686// CFG: Queries for BlkExprs. 2687//===----------------------------------------------------------------------===// 2688 2689namespace { 2690 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2691} 2692 2693static void FindSubExprAssignments(Stmt *S, 2694 llvm::SmallPtrSet<Expr*,50>& Set) { 2695 if (!S) 2696 return; 2697 2698 for (Stmt::child_range I = S->children(); I; ++I) { 2699 Stmt *child = *I; 2700 if (!child) 2701 continue; 2702 2703 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2704 if (B->isAssignmentOp()) Set.insert(B); 2705 2706 FindSubExprAssignments(child, Set); 2707 } 2708} 2709 2710static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2711 BlkExprMapTy* M = new BlkExprMapTy(); 2712 2713 // Look for assignments that are used as subexpressions. These are the only 2714 // assignments that we want to *possibly* register as a block-level 2715 // expression. Basically, if an assignment occurs both in a subexpression and 2716 // at the block-level, it is a block-level expression. 2717 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2718 2719 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2720 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2721 if (CFGStmt S = BI->getAs<CFGStmt>()) 2722 FindSubExprAssignments(S, SubExprAssignments); 2723 2724 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2725 2726 // Iterate over the statements again on identify the Expr* and Stmt* at the 2727 // block-level that are block-level expressions. 2728 2729 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2730 CFGStmt CS = BI->getAs<CFGStmt>(); 2731 if (!CS.isValid()) 2732 continue; 2733 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2734 2735 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2736 // Assignment expressions that are not nested within another 2737 // expression are really "statements" whose value is never used by 2738 // another expression. 2739 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2740 continue; 2741 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2742 // Special handling for statement expressions. The last statement in 2743 // the statement expression is also a block-level expr. 2744 const CompoundStmt* C = Terminator->getSubStmt(); 2745 if (!C->body_empty()) { 2746 unsigned x = M->size(); 2747 (*M)[C->body_back()] = x; 2748 } 2749 } 2750 2751 unsigned x = M->size(); 2752 (*M)[Exp] = x; 2753 } 2754 } 2755 2756 // Look at terminators. The condition is a block-level expression. 2757 2758 Stmt* S = (*I)->getTerminatorCondition(); 2759 2760 if (S && M->find(S) == M->end()) { 2761 unsigned x = M->size(); 2762 (*M)[S] = x; 2763 } 2764 } 2765 2766 return M; 2767} 2768 2769CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2770 assert(S != NULL); 2771 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2772 2773 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2774 BlkExprMapTy::iterator I = M->find(S); 2775 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2776} 2777 2778unsigned CFG::getNumBlkExprs() { 2779 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2780 return M->size(); 2781 2782 // We assume callers interested in the number of BlkExprs will want 2783 // the map constructed if it doesn't already exist. 2784 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2785 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2786} 2787 2788//===----------------------------------------------------------------------===// 2789// Filtered walking of the CFG. 2790//===----------------------------------------------------------------------===// 2791 2792bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2793 const CFGBlock *From, const CFGBlock *To) { 2794 2795 if (F.IgnoreDefaultsWithCoveredEnums) { 2796 // If the 'To' has no label or is labeled but the label isn't a 2797 // CaseStmt then filter this edge. 2798 if (const SwitchStmt *S = 2799 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 2800 if (S->isAllEnumCasesCovered()) { 2801 const Stmt *L = To->getLabel(); 2802 if (!L || !isa<CaseStmt>(L)) 2803 return true; 2804 } 2805 } 2806 } 2807 2808 return false; 2809} 2810 2811//===----------------------------------------------------------------------===// 2812// Cleanup: CFG dstor. 2813//===----------------------------------------------------------------------===// 2814 2815CFG::~CFG() { 2816 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2817} 2818 2819//===----------------------------------------------------------------------===// 2820// CFG pretty printing 2821//===----------------------------------------------------------------------===// 2822 2823namespace { 2824 2825class StmtPrinterHelper : public PrinterHelper { 2826 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2827 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2828 StmtMapTy StmtMap; 2829 DeclMapTy DeclMap; 2830 signed currentBlock; 2831 unsigned currentStmt; 2832 const LangOptions &LangOpts; 2833public: 2834 2835 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2836 : currentBlock(0), currentStmt(0), LangOpts(LO) { 2837 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2838 unsigned j = 1; 2839 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2840 BI != BEnd; ++BI, ++j ) { 2841 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2842 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2843 StmtMap[SE] = P; 2844 2845 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2846 DeclMap[DS->getSingleDecl()] = P; 2847 2848 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2849 if (VarDecl* VD = IS->getConditionVariable()) 2850 DeclMap[VD] = P; 2851 2852 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2853 if (VarDecl* VD = FS->getConditionVariable()) 2854 DeclMap[VD] = P; 2855 2856 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2857 if (VarDecl* VD = WS->getConditionVariable()) 2858 DeclMap[VD] = P; 2859 2860 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2861 if (VarDecl* VD = SS->getConditionVariable()) 2862 DeclMap[VD] = P; 2863 2864 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2865 if (VarDecl* VD = CS->getExceptionDecl()) 2866 DeclMap[VD] = P; 2867 } 2868 } 2869 } 2870 } 2871 } 2872 2873 virtual ~StmtPrinterHelper() {} 2874 2875 const LangOptions &getLangOpts() const { return LangOpts; } 2876 void setBlockID(signed i) { currentBlock = i; } 2877 void setStmtID(unsigned i) { currentStmt = i; } 2878 2879 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2880 StmtMapTy::iterator I = StmtMap.find(S); 2881 2882 if (I == StmtMap.end()) 2883 return false; 2884 2885 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 2886 && I->second.second == currentStmt) { 2887 return false; 2888 } 2889 2890 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2891 return true; 2892 } 2893 2894 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2895 DeclMapTy::iterator I = DeclMap.find(D); 2896 2897 if (I == DeclMap.end()) 2898 return false; 2899 2900 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 2901 && I->second.second == currentStmt) { 2902 return false; 2903 } 2904 2905 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2906 return true; 2907 } 2908}; 2909} // end anonymous namespace 2910 2911 2912namespace { 2913class CFGBlockTerminatorPrint 2914 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2915 2916 llvm::raw_ostream& OS; 2917 StmtPrinterHelper* Helper; 2918 PrintingPolicy Policy; 2919public: 2920 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2921 const PrintingPolicy &Policy) 2922 : OS(os), Helper(helper), Policy(Policy) {} 2923 2924 void VisitIfStmt(IfStmt* I) { 2925 OS << "if "; 2926 I->getCond()->printPretty(OS,Helper,Policy); 2927 } 2928 2929 // Default case. 2930 void VisitStmt(Stmt* Terminator) { 2931 Terminator->printPretty(OS, Helper, Policy); 2932 } 2933 2934 void VisitForStmt(ForStmt* F) { 2935 OS << "for (" ; 2936 if (F->getInit()) 2937 OS << "..."; 2938 OS << "; "; 2939 if (Stmt* C = F->getCond()) 2940 C->printPretty(OS, Helper, Policy); 2941 OS << "; "; 2942 if (F->getInc()) 2943 OS << "..."; 2944 OS << ")"; 2945 } 2946 2947 void VisitWhileStmt(WhileStmt* W) { 2948 OS << "while " ; 2949 if (Stmt* C = W->getCond()) 2950 C->printPretty(OS, Helper, Policy); 2951 } 2952 2953 void VisitDoStmt(DoStmt* D) { 2954 OS << "do ... while "; 2955 if (Stmt* C = D->getCond()) 2956 C->printPretty(OS, Helper, Policy); 2957 } 2958 2959 void VisitSwitchStmt(SwitchStmt* Terminator) { 2960 OS << "switch "; 2961 Terminator->getCond()->printPretty(OS, Helper, Policy); 2962 } 2963 2964 void VisitCXXTryStmt(CXXTryStmt* CS) { 2965 OS << "try ..."; 2966 } 2967 2968 void VisitConditionalOperator(ConditionalOperator* C) { 2969 C->getCond()->printPretty(OS, Helper, Policy); 2970 OS << " ? ... : ..."; 2971 } 2972 2973 void VisitChooseExpr(ChooseExpr* C) { 2974 OS << "__builtin_choose_expr( "; 2975 C->getCond()->printPretty(OS, Helper, Policy); 2976 OS << " )"; 2977 } 2978 2979 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2980 OS << "goto *"; 2981 I->getTarget()->printPretty(OS, Helper, Policy); 2982 } 2983 2984 void VisitBinaryOperator(BinaryOperator* B) { 2985 if (!B->isLogicalOp()) { 2986 VisitExpr(B); 2987 return; 2988 } 2989 2990 B->getLHS()->printPretty(OS, Helper, Policy); 2991 2992 switch (B->getOpcode()) { 2993 case BO_LOr: 2994 OS << " || ..."; 2995 return; 2996 case BO_LAnd: 2997 OS << " && ..."; 2998 return; 2999 default: 3000 assert(false && "Invalid logical operator."); 3001 } 3002 } 3003 3004 void VisitExpr(Expr* E) { 3005 E->printPretty(OS, Helper, Policy); 3006 } 3007}; 3008} // end anonymous namespace 3009 3010static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3011 const CFGElement &E) { 3012 if (CFGStmt CS = E.getAs<CFGStmt>()) { 3013 Stmt *S = CS; 3014 3015 if (Helper) { 3016 3017 // special printing for statement-expressions. 3018 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3019 CompoundStmt* Sub = SE->getSubStmt(); 3020 3021 if (Sub->children()) { 3022 OS << "({ ... ; "; 3023 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3024 OS << " })\n"; 3025 return; 3026 } 3027 } 3028 // special printing for comma expressions. 3029 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3030 if (B->getOpcode() == BO_Comma) { 3031 OS << "... , "; 3032 Helper->handledStmt(B->getRHS(),OS); 3033 OS << '\n'; 3034 return; 3035 } 3036 } 3037 } 3038 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3039 3040 if (isa<CXXOperatorCallExpr>(S)) { 3041 OS << " (OperatorCall)"; 3042 } else if (isa<CXXBindTemporaryExpr>(S)) { 3043 OS << " (BindTemporary)"; 3044 } 3045 3046 // Expressions need a newline. 3047 if (isa<Expr>(S)) 3048 OS << '\n'; 3049 3050 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 3051 CXXCtorInitializer* I = IE; 3052 if (I->isBaseInitializer()) 3053 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3054 else OS << I->getAnyMember()->getName(); 3055 3056 OS << "("; 3057 if (Expr* IE = I->getInit()) 3058 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3059 OS << ")"; 3060 3061 if (I->isBaseInitializer()) 3062 OS << " (Base initializer)\n"; 3063 else OS << " (Member initializer)\n"; 3064 3065 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 3066 VarDecl* VD = DE.getVarDecl(); 3067 Helper->handleDecl(VD, OS); 3068 3069 const Type* T = VD->getType().getTypePtr(); 3070 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3071 T = RT->getPointeeType().getTypePtr(); 3072 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3073 T = ET; 3074 3075 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3076 OS << " (Implicit destructor)\n"; 3077 3078 } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { 3079 const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); 3080 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3081 OS << " (Base object destructor)\n"; 3082 3083 } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { 3084 FieldDecl *FD = ME.getFieldDecl(); 3085 3086 const Type *T = FD->getType().getTypePtr(); 3087 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3088 T = ET; 3089 3090 OS << "this->" << FD->getName(); 3091 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3092 OS << " (Member object destructor)\n"; 3093 3094 } else if (CFGTemporaryDtor TE = E.getAs<CFGTemporaryDtor>()) { 3095 CXXBindTemporaryExpr *BT = TE.getBindTemporaryExpr(); 3096 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3097 OS << " (Temporary object destructor)\n"; 3098 } 3099} 3100 3101static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3102 const CFGBlock& B, 3103 StmtPrinterHelper* Helper, bool print_edges) { 3104 3105 if (Helper) Helper->setBlockID(B.getBlockID()); 3106 3107 // Print the header. 3108 OS << "\n [ B" << B.getBlockID(); 3109 3110 if (&B == &cfg->getEntry()) 3111 OS << " (ENTRY) ]\n"; 3112 else if (&B == &cfg->getExit()) 3113 OS << " (EXIT) ]\n"; 3114 else if (&B == cfg->getIndirectGotoBlock()) 3115 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3116 else 3117 OS << " ]\n"; 3118 3119 // Print the label of this block. 3120 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3121 3122 if (print_edges) 3123 OS << " "; 3124 3125 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3126 OS << L->getName(); 3127 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3128 OS << "case "; 3129 C->getLHS()->printPretty(OS, Helper, 3130 PrintingPolicy(Helper->getLangOpts())); 3131 if (C->getRHS()) { 3132 OS << " ... "; 3133 C->getRHS()->printPretty(OS, Helper, 3134 PrintingPolicy(Helper->getLangOpts())); 3135 } 3136 } else if (isa<DefaultStmt>(Label)) 3137 OS << "default"; 3138 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3139 OS << "catch ("; 3140 if (CS->getExceptionDecl()) 3141 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3142 0); 3143 else 3144 OS << "..."; 3145 OS << ")"; 3146 3147 } else 3148 assert(false && "Invalid label statement in CFGBlock."); 3149 3150 OS << ":\n"; 3151 } 3152 3153 // Iterate through the statements in the block and print them. 3154 unsigned j = 1; 3155 3156 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3157 I != E ; ++I, ++j ) { 3158 3159 // Print the statement # in the basic block and the statement itself. 3160 if (print_edges) 3161 OS << " "; 3162 3163 OS << llvm::format("%3d", j) << ": "; 3164 3165 if (Helper) 3166 Helper->setStmtID(j); 3167 3168 print_elem(OS,Helper,*I); 3169 } 3170 3171 // Print the terminator of this block. 3172 if (B.getTerminator()) { 3173 if (print_edges) 3174 OS << " "; 3175 3176 OS << " T: "; 3177 3178 if (Helper) Helper->setBlockID(-1); 3179 3180 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3181 PrintingPolicy(Helper->getLangOpts())); 3182 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3183 OS << '\n'; 3184 } 3185 3186 if (print_edges) { 3187 // Print the predecessors of this block. 3188 OS << " Predecessors (" << B.pred_size() << "):"; 3189 unsigned i = 0; 3190 3191 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3192 I != E; ++I, ++i) { 3193 3194 if (i == 8 || (i-8) == 0) 3195 OS << "\n "; 3196 3197 OS << " B" << (*I)->getBlockID(); 3198 } 3199 3200 OS << '\n'; 3201 3202 // Print the successors of this block. 3203 OS << " Successors (" << B.succ_size() << "):"; 3204 i = 0; 3205 3206 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3207 I != E; ++I, ++i) { 3208 3209 if (i == 8 || (i-8) % 10 == 0) 3210 OS << "\n "; 3211 3212 if (*I) 3213 OS << " B" << (*I)->getBlockID(); 3214 else 3215 OS << " NULL"; 3216 } 3217 3218 OS << '\n'; 3219 } 3220} 3221 3222 3223/// dump - A simple pretty printer of a CFG that outputs to stderr. 3224void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3225 3226/// print - A simple pretty printer of a CFG that outputs to an ostream. 3227void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3228 StmtPrinterHelper Helper(this, LO); 3229 3230 // Print the entry block. 3231 print_block(OS, this, getEntry(), &Helper, true); 3232 3233 // Iterate through the CFGBlocks and print them one by one. 3234 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3235 // Skip the entry block, because we already printed it. 3236 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3237 continue; 3238 3239 print_block(OS, this, **I, &Helper, true); 3240 } 3241 3242 // Print the exit block. 3243 print_block(OS, this, getExit(), &Helper, true); 3244 OS.flush(); 3245} 3246 3247/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3248void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3249 print(llvm::errs(), cfg, LO); 3250} 3251 3252/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3253/// Generally this will only be called from CFG::print. 3254void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3255 const LangOptions &LO) const { 3256 StmtPrinterHelper Helper(cfg, LO); 3257 print_block(OS, cfg, *this, &Helper, true); 3258} 3259 3260/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3261void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3262 const LangOptions &LO) const { 3263 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3264 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3265} 3266 3267Stmt* CFGBlock::getTerminatorCondition() { 3268 Stmt *Terminator = this->Terminator; 3269 if (!Terminator) 3270 return NULL; 3271 3272 Expr* E = NULL; 3273 3274 switch (Terminator->getStmtClass()) { 3275 default: 3276 break; 3277 3278 case Stmt::ForStmtClass: 3279 E = cast<ForStmt>(Terminator)->getCond(); 3280 break; 3281 3282 case Stmt::WhileStmtClass: 3283 E = cast<WhileStmt>(Terminator)->getCond(); 3284 break; 3285 3286 case Stmt::DoStmtClass: 3287 E = cast<DoStmt>(Terminator)->getCond(); 3288 break; 3289 3290 case Stmt::IfStmtClass: 3291 E = cast<IfStmt>(Terminator)->getCond(); 3292 break; 3293 3294 case Stmt::ChooseExprClass: 3295 E = cast<ChooseExpr>(Terminator)->getCond(); 3296 break; 3297 3298 case Stmt::IndirectGotoStmtClass: 3299 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3300 break; 3301 3302 case Stmt::SwitchStmtClass: 3303 E = cast<SwitchStmt>(Terminator)->getCond(); 3304 break; 3305 3306 case Stmt::ConditionalOperatorClass: 3307 E = cast<ConditionalOperator>(Terminator)->getCond(); 3308 break; 3309 3310 case Stmt::BinaryOperatorClass: // '&&' and '||' 3311 E = cast<BinaryOperator>(Terminator)->getLHS(); 3312 break; 3313 3314 case Stmt::ObjCForCollectionStmtClass: 3315 return Terminator; 3316 } 3317 3318 return E ? E->IgnoreParens() : NULL; 3319} 3320 3321bool CFGBlock::hasBinaryBranchTerminator() const { 3322 const Stmt *Terminator = this->Terminator; 3323 if (!Terminator) 3324 return false; 3325 3326 Expr* E = NULL; 3327 3328 switch (Terminator->getStmtClass()) { 3329 default: 3330 return false; 3331 3332 case Stmt::ForStmtClass: 3333 case Stmt::WhileStmtClass: 3334 case Stmt::DoStmtClass: 3335 case Stmt::IfStmtClass: 3336 case Stmt::ChooseExprClass: 3337 case Stmt::ConditionalOperatorClass: 3338 case Stmt::BinaryOperatorClass: 3339 return true; 3340 } 3341 3342 return E ? E->IgnoreParens() : NULL; 3343} 3344 3345 3346//===----------------------------------------------------------------------===// 3347// CFG Graphviz Visualization 3348//===----------------------------------------------------------------------===// 3349 3350 3351#ifndef NDEBUG 3352static StmtPrinterHelper* GraphHelper; 3353#endif 3354 3355void CFG::viewCFG(const LangOptions &LO) const { 3356#ifndef NDEBUG 3357 StmtPrinterHelper H(this, LO); 3358 GraphHelper = &H; 3359 llvm::ViewGraph(this,"CFG"); 3360 GraphHelper = NULL; 3361#endif 3362} 3363 3364namespace llvm { 3365template<> 3366struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3367 3368 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3369 3370 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3371 3372#ifndef NDEBUG 3373 std::string OutSStr; 3374 llvm::raw_string_ostream Out(OutSStr); 3375 print_block(Out,Graph, *Node, GraphHelper, false); 3376 std::string& OutStr = Out.str(); 3377 3378 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3379 3380 // Process string output to make it nicer... 3381 for (unsigned i = 0; i != OutStr.length(); ++i) 3382 if (OutStr[i] == '\n') { // Left justify 3383 OutStr[i] = '\\'; 3384 OutStr.insert(OutStr.begin()+i+1, 'l'); 3385 } 3386 3387 return OutStr; 3388#else 3389 return ""; 3390#endif 3391 } 3392}; 3393} // end namespace llvm 3394