CFG.cpp revision 218893
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 BumpVector<VarDecl*> 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 BumpVectorContext ctx; 164 165 /// Automatic variables in order of declaration. 166 AutomaticVarsTy Vars; 167 /// Iterator to variable in previous scope that was declared just before 168 /// begin of this scope. 169 const_iterator Prev; 170 171public: 172 /// Constructs empty scope linked to previous scope in specified place. 173 LocalScope(BumpVectorContext &ctx, const_iterator P) 174 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 175 176 /// Begin of scope in direction of CFG building (backwards). 177 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 178 179 void addVar(VarDecl* VD) { 180 Vars.push_back(VD, ctx); 181 } 182}; 183 184/// distance - Calculates distance from this to L. L must be reachable from this 185/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 186/// number of scopes between this and L. 187int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 188 int D = 0; 189 const_iterator F = *this; 190 while (F.Scope != L.Scope) { 191 assert (F != const_iterator() 192 && "L iterator is not reachable from F iterator."); 193 D += F.VarIter; 194 F = F.Scope->Prev; 195 } 196 D += F.VarIter - L.VarIter; 197 return D; 198} 199 200/// BlockScopePosPair - Structure for specifying position in CFG during its 201/// build process. It consists of CFGBlock that specifies position in CFG graph 202/// and LocalScope::const_iterator that specifies position in LocalScope graph. 203struct BlockScopePosPair { 204 BlockScopePosPair() : block(0) {} 205 BlockScopePosPair(CFGBlock* b, LocalScope::const_iterator scopePos) 206 : block(b), scopePosition(scopePos) {} 207 208 CFGBlock *block; 209 LocalScope::const_iterator scopePosition; 210}; 211 212/// CFGBuilder - This class implements CFG construction from an AST. 213/// The builder is stateful: an instance of the builder should be used to only 214/// construct a single CFG. 215/// 216/// Example usage: 217/// 218/// CFGBuilder builder; 219/// CFG* cfg = builder.BuildAST(stmt1); 220/// 221/// CFG construction is done via a recursive walk of an AST. We actually parse 222/// the AST in reverse order so that the successor of a basic block is 223/// constructed prior to its predecessor. This allows us to nicely capture 224/// implicit fall-throughs without extra basic blocks. 225/// 226class CFGBuilder { 227 typedef BlockScopePosPair JumpTarget; 228 typedef BlockScopePosPair JumpSource; 229 230 ASTContext *Context; 231 llvm::OwningPtr<CFG> cfg; 232 233 CFGBlock* Block; 234 CFGBlock* Succ; 235 JumpTarget ContinueJumpTarget; 236 JumpTarget BreakJumpTarget; 237 CFGBlock* SwitchTerminatedBlock; 238 CFGBlock* DefaultCaseBlock; 239 CFGBlock* TryTerminatedBlock; 240 241 // Current position in local scope. 242 LocalScope::const_iterator ScopePos; 243 244 // LabelMap records the mapping from Label expressions to their jump targets. 245 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 246 LabelMapTy LabelMap; 247 248 // A list of blocks that end with a "goto" that must be backpatched to their 249 // resolved targets upon completion of CFG construction. 250 typedef std::vector<JumpSource> BackpatchBlocksTy; 251 BackpatchBlocksTy BackpatchBlocks; 252 253 // A list of labels whose address has been taken (for indirect gotos). 254 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 255 LabelSetTy AddressTakenLabels; 256 257 bool badCFG; 258 CFG::BuildOptions BuildOpts; 259 260public: 261 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 262 Block(NULL), Succ(NULL), 263 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 264 TryTerminatedBlock(NULL), badCFG(false) {} 265 266 // buildCFG - Used by external clients to construct the CFG. 267 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 268 CFG::BuildOptions BO); 269 270private: 271 // Visitors to walk an AST and construct the CFG. 272 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 273 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 274 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 275 CFGBlock *VisitBreakStmt(BreakStmt *B); 276 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 277 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 278 AddStmtChoice asc); 279 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 280 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 281 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 282 AddStmtChoice asc); 283 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 284 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 285 AddStmtChoice asc); 286 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 287 AddStmtChoice asc); 288 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 289 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 290 CFGBlock *VisitCaseStmt(CaseStmt *C); 291 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 292 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 293 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 294 AddStmtChoice asc); 295 CFGBlock *VisitContinueStmt(ContinueStmt *C); 296 CFGBlock *VisitDeclStmt(DeclStmt *DS); 297 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 298 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 299 CFGBlock *VisitDoStmt(DoStmt *D); 300 CFGBlock *VisitForStmt(ForStmt *F); 301 CFGBlock *VisitGotoStmt(GotoStmt* G); 302 CFGBlock *VisitIfStmt(IfStmt *I); 303 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 304 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 305 CFGBlock *VisitLabelStmt(LabelStmt *L); 306 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 307 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 308 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 309 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 310 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 311 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 312 CFGBlock *VisitReturnStmt(ReturnStmt* R); 313 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 314 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 315 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 316 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 317 CFGBlock *VisitWhileStmt(WhileStmt *W); 318 319 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 320 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 321 CFGBlock *VisitChildren(Stmt* S); 322 323 // Visitors to walk an AST and generate destructors of temporaries in 324 // full expression. 325 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 326 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 327 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 328 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 329 bool BindToTemporary); 330 CFGBlock * 331 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 332 bool BindToTemporary); 333 334 // NYS == Not Yet Supported 335 CFGBlock* NYS() { 336 badCFG = true; 337 return Block; 338 } 339 340 void autoCreateBlock() { if (!Block) Block = createBlock(); } 341 CFGBlock *createBlock(bool add_successor = true); 342 343 CFGBlock *addStmt(Stmt *S) { 344 return Visit(S, AddStmtChoice::AlwaysAdd); 345 } 346 CFGBlock *addInitializer(CXXCtorInitializer *I); 347 void addAutomaticObjDtors(LocalScope::const_iterator B, 348 LocalScope::const_iterator E, Stmt* S); 349 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 350 351 // Local scopes creation. 352 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 353 354 void addLocalScopeForStmt(Stmt* S); 355 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 356 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 357 358 void addLocalScopeAndDtors(Stmt* S); 359 360 // Interface to CFGBlock - adding CFGElements. 361 void appendStmt(CFGBlock *B, Stmt *S, 362 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 363 B->appendStmt(S, cfg->getBumpVectorContext()); 364 } 365 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 366 B->appendInitializer(I, cfg->getBumpVectorContext()); 367 } 368 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 369 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 370 } 371 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 372 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 373 } 374 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 375 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 376 } 377 378 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 379 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 380 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 381 LocalScope::const_iterator E, Stmt* S); 382 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 383 LocalScope::const_iterator B, LocalScope::const_iterator E); 384 385 void addSuccessor(CFGBlock *B, CFGBlock *S) { 386 B->addSuccessor(S, cfg->getBumpVectorContext()); 387 } 388 389 /// TryResult - a class representing a variant over the values 390 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 391 /// and is used by the CFGBuilder to decide if a branch condition 392 /// can be decided up front during CFG construction. 393 class TryResult { 394 int X; 395 public: 396 TryResult(bool b) : X(b ? 1 : 0) {} 397 TryResult() : X(-1) {} 398 399 bool isTrue() const { return X == 1; } 400 bool isFalse() const { return X == 0; } 401 bool isKnown() const { return X >= 0; } 402 void negate() { 403 assert(isKnown()); 404 X ^= 0x1; 405 } 406 }; 407 408 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 409 /// if we can evaluate to a known value, otherwise return -1. 410 TryResult tryEvaluateBool(Expr *S) { 411 if (!BuildOpts.PruneTriviallyFalseEdges) 412 return TryResult(); 413 414 Expr::EvalResult Result; 415 if (!S->isTypeDependent() && !S->isValueDependent() && 416 S->Evaluate(Result, *Context) && Result.Val.isInt()) 417 return Result.Val.getInt().getBoolValue(); 418 419 return TryResult(); 420 } 421}; 422 423// FIXME: Add support for dependent-sized array types in C++? 424// Does it even make sense to build a CFG for an uninstantiated template? 425static const VariableArrayType *FindVA(const Type *t) { 426 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 427 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 428 if (vat->getSizeExpr()) 429 return vat; 430 431 t = vt->getElementType().getTypePtr(); 432 } 433 434 return 0; 435} 436 437/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 438/// arbitrary statement. Examples include a single expression or a function 439/// body (compound statement). The ownership of the returned CFG is 440/// transferred to the caller. If CFG construction fails, this method returns 441/// NULL. 442CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 443 CFG::BuildOptions BO) { 444 445 Context = C; 446 assert(cfg.get()); 447 if (!Statement) 448 return NULL; 449 450 BuildOpts = BO; 451 452 // Create an empty block that will serve as the exit block for the CFG. Since 453 // this is the first block added to the CFG, it will be implicitly registered 454 // as the exit block. 455 Succ = createBlock(); 456 assert(Succ == &cfg->getExit()); 457 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 458 459 if (BuildOpts.AddImplicitDtors) 460 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 461 addImplicitDtorsForDestructor(DD); 462 463 // Visit the statements and create the CFG. 464 CFGBlock *B = addStmt(Statement); 465 466 if (badCFG) 467 return NULL; 468 469 // For C++ constructor add initializers to CFG. 470 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 471 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 472 E = CD->init_rend(); I != E; ++I) { 473 B = addInitializer(*I); 474 if (badCFG) 475 return NULL; 476 } 477 } 478 479 if (B) 480 Succ = B; 481 482 // Backpatch the gotos whose label -> block mappings we didn't know when we 483 // encountered them. 484 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 485 E = BackpatchBlocks.end(); I != E; ++I ) { 486 487 CFGBlock* B = I->block; 488 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 489 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 490 491 // If there is no target for the goto, then we are looking at an 492 // incomplete AST. Handle this by not registering a successor. 493 if (LI == LabelMap.end()) continue; 494 495 JumpTarget JT = LI->second; 496 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 497 JT.scopePosition); 498 addSuccessor(B, JT.block); 499 } 500 501 // Add successors to the Indirect Goto Dispatch block (if we have one). 502 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 503 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 504 E = AddressTakenLabels.end(); I != E; ++I ) { 505 506 // Lookup the target block. 507 LabelMapTy::iterator LI = LabelMap.find(*I); 508 509 // If there is no target block that contains label, then we are looking 510 // at an incomplete AST. Handle this by not registering a successor. 511 if (LI == LabelMap.end()) continue; 512 513 addSuccessor(B, LI->second.block); 514 } 515 516 // Create an empty entry block that has no predecessors. 517 cfg->setEntry(createBlock()); 518 519 return cfg.take(); 520} 521 522/// createBlock - Used to lazily create blocks that are connected 523/// to the current (global) succcessor. 524CFGBlock* CFGBuilder::createBlock(bool add_successor) { 525 CFGBlock* B = cfg->createBlock(); 526 if (add_successor && Succ) 527 addSuccessor(B, Succ); 528 return B; 529} 530 531/// addInitializer - Add C++ base or member initializer element to CFG. 532CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 533 if (!BuildOpts.AddInitializers) 534 return Block; 535 536 bool IsReference = false; 537 bool HasTemporaries = false; 538 539 // Destructors of temporaries in initialization expression should be called 540 // after initialization finishes. 541 Expr *Init = I->getInit(); 542 if (Init) { 543 if (FieldDecl *FD = I->getAnyMember()) 544 IsReference = FD->getType()->isReferenceType(); 545 HasTemporaries = isa<ExprWithCleanups>(Init); 546 547 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 548 // Generate destructors for temporaries in initialization expression. 549 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 550 IsReference); 551 } 552 } 553 554 autoCreateBlock(); 555 appendInitializer(Block, I); 556 557 if (Init) { 558 if (HasTemporaries) { 559 // For expression with temporaries go directly to subexpression to omit 560 // generating destructors for the second time. 561 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 562 } 563 return Visit(Init); 564 } 565 566 return Block; 567} 568 569/// addAutomaticObjDtors - Add to current block automatic objects destructors 570/// for objects in range of local scope positions. Use S as trigger statement 571/// for destructors. 572void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 573 LocalScope::const_iterator E, Stmt* S) { 574 if (!BuildOpts.AddImplicitDtors) 575 return; 576 577 if (B == E) 578 return; 579 580 autoCreateBlock(); 581 appendAutomaticObjDtors(Block, B, E, S); 582} 583 584/// addImplicitDtorsForDestructor - Add implicit destructors generated for 585/// base and member objects in destructor. 586void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 587 assert (BuildOpts.AddImplicitDtors 588 && "Can be called only when dtors should be added"); 589 const CXXRecordDecl *RD = DD->getParent(); 590 591 // At the end destroy virtual base objects. 592 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 593 VE = RD->vbases_end(); VI != VE; ++VI) { 594 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 595 if (!CD->hasTrivialDestructor()) { 596 autoCreateBlock(); 597 appendBaseDtor(Block, VI); 598 } 599 } 600 601 // Before virtual bases destroy direct base objects. 602 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 603 BE = RD->bases_end(); BI != BE; ++BI) { 604 if (!BI->isVirtual()) { 605 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 606 if (!CD->hasTrivialDestructor()) { 607 autoCreateBlock(); 608 appendBaseDtor(Block, BI); 609 } 610 } 611 } 612 613 // First destroy member objects. 614 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 615 FE = RD->field_end(); FI != FE; ++FI) { 616 // Check for constant size array. Set type to array element type. 617 QualType QT = FI->getType(); 618 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 619 if (AT->getSize() == 0) 620 continue; 621 QT = AT->getElementType(); 622 } 623 624 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 625 if (!CD->hasTrivialDestructor()) { 626 autoCreateBlock(); 627 appendMemberDtor(Block, *FI); 628 } 629 } 630} 631 632/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 633/// way return valid LocalScope object. 634LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 635 if (!Scope) { 636 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 637 Scope = alloc.Allocate<LocalScope>(); 638 BumpVectorContext ctx(alloc); 639 new (Scope) LocalScope(ctx, ScopePos); 640 } 641 return Scope; 642} 643 644/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 645/// that should create implicit scope (e.g. if/else substatements). 646void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 647 if (!BuildOpts.AddImplicitDtors) 648 return; 649 650 LocalScope *Scope = 0; 651 652 // For compound statement we will be creating explicit scope. 653 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 654 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 655 ; BI != BE; ++BI) { 656 Stmt *SI = *BI; 657 if (LabelStmt *LS = dyn_cast<LabelStmt>(SI)) 658 SI = LS->getSubStmt(); 659 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 660 Scope = addLocalScopeForDeclStmt(DS, Scope); 661 } 662 return; 663 } 664 665 // For any other statement scope will be implicit and as such will be 666 // interesting only for DeclStmt. 667 if (LabelStmt *LS = dyn_cast<LabelStmt>(S)) 668 S = LS->getSubStmt(); 669 if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) 670 addLocalScopeForDeclStmt(DS); 671} 672 673/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 674/// reuse Scope if not NULL. 675LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 676 LocalScope* Scope) { 677 if (!BuildOpts.AddImplicitDtors) 678 return Scope; 679 680 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 681 ; DI != DE; ++DI) { 682 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 683 Scope = addLocalScopeForVarDecl(VD, Scope); 684 } 685 return Scope; 686} 687 688/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 689/// create add scope for automatic objects and temporary objects bound to 690/// const reference. Will reuse Scope if not NULL. 691LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 692 LocalScope* Scope) { 693 if (!BuildOpts.AddImplicitDtors) 694 return Scope; 695 696 // Check if variable is local. 697 switch (VD->getStorageClass()) { 698 case SC_None: 699 case SC_Auto: 700 case SC_Register: 701 break; 702 default: return Scope; 703 } 704 705 // Check for const references bound to temporary. Set type to pointee. 706 QualType QT = VD->getType(); 707 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 708 QT = RT->getPointeeType(); 709 if (!QT.isConstQualified()) 710 return Scope; 711 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 712 return Scope; 713 } 714 715 // Check for constant size array. Set type to array element type. 716 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 717 if (AT->getSize() == 0) 718 return Scope; 719 QT = AT->getElementType(); 720 } 721 722 // Check if type is a C++ class with non-trivial destructor. 723 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 724 if (!CD->hasTrivialDestructor()) { 725 // Add the variable to scope 726 Scope = createOrReuseLocalScope(Scope); 727 Scope->addVar(VD); 728 ScopePos = Scope->begin(); 729 } 730 return Scope; 731} 732 733/// addLocalScopeAndDtors - For given statement add local scope for it and 734/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 735void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 736 if (!BuildOpts.AddImplicitDtors) 737 return; 738 739 LocalScope::const_iterator scopeBeginPos = ScopePos; 740 addLocalScopeForStmt(S); 741 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 742} 743 744/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 745/// automatic storage duration to CFGBlock's elements vector. Insertion will be 746/// performed in place specified with iterator. 747void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 748 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 749 BumpVectorContext& C = cfg->getBumpVectorContext(); 750 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 751 while (B != E) 752 I = Blk->insertAutomaticObjDtor(I, *B++, S); 753} 754 755/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 756/// automatic storage duration to CFGBlock's elements vector. Elements will be 757/// appended to physical end of the vector which happens to be logical 758/// beginning. 759void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 760 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 761 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 762} 763 764/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 765/// variables with automatic storage duration to CFGBlock's elements vector. 766/// Elements will be prepended to physical beginning of the vector which 767/// happens to be logical end. Use blocks terminator as statement that specifies 768/// destructors call site. 769void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 770 LocalScope::const_iterator B, LocalScope::const_iterator E) { 771 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 772} 773 774/// Visit - Walk the subtree of a statement and add extra 775/// blocks for ternary operators, &&, and ||. We also process "," and 776/// DeclStmts (which may contain nested control-flow). 777CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 778tryAgain: 779 if (!S) { 780 badCFG = true; 781 return 0; 782 } 783 switch (S->getStmtClass()) { 784 default: 785 return VisitStmt(S, asc); 786 787 case Stmt::AddrLabelExprClass: 788 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 789 790 case Stmt::BinaryConditionalOperatorClass: 791 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 792 793 case Stmt::BinaryOperatorClass: 794 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 795 796 case Stmt::BlockExprClass: 797 return VisitBlockExpr(cast<BlockExpr>(S), asc); 798 799 case Stmt::BreakStmtClass: 800 return VisitBreakStmt(cast<BreakStmt>(S)); 801 802 case Stmt::CallExprClass: 803 case Stmt::CXXOperatorCallExprClass: 804 return VisitCallExpr(cast<CallExpr>(S), asc); 805 806 case Stmt::CaseStmtClass: 807 return VisitCaseStmt(cast<CaseStmt>(S)); 808 809 case Stmt::ChooseExprClass: 810 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 811 812 case Stmt::CompoundStmtClass: 813 return VisitCompoundStmt(cast<CompoundStmt>(S)); 814 815 case Stmt::ConditionalOperatorClass: 816 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 817 818 case Stmt::ContinueStmtClass: 819 return VisitContinueStmt(cast<ContinueStmt>(S)); 820 821 case Stmt::CXXCatchStmtClass: 822 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 823 824 case Stmt::ExprWithCleanupsClass: 825 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 826 827 case Stmt::CXXBindTemporaryExprClass: 828 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 829 830 case Stmt::CXXConstructExprClass: 831 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 832 833 case Stmt::CXXFunctionalCastExprClass: 834 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 835 836 case Stmt::CXXTemporaryObjectExprClass: 837 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 838 839 case Stmt::CXXMemberCallExprClass: 840 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 841 842 case Stmt::CXXThrowExprClass: 843 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 844 845 case Stmt::CXXTryStmtClass: 846 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 847 848 case Stmt::DeclStmtClass: 849 return VisitDeclStmt(cast<DeclStmt>(S)); 850 851 case Stmt::DefaultStmtClass: 852 return VisitDefaultStmt(cast<DefaultStmt>(S)); 853 854 case Stmt::DoStmtClass: 855 return VisitDoStmt(cast<DoStmt>(S)); 856 857 case Stmt::ForStmtClass: 858 return VisitForStmt(cast<ForStmt>(S)); 859 860 case Stmt::GotoStmtClass: 861 return VisitGotoStmt(cast<GotoStmt>(S)); 862 863 case Stmt::IfStmtClass: 864 return VisitIfStmt(cast<IfStmt>(S)); 865 866 case Stmt::ImplicitCastExprClass: 867 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 868 869 case Stmt::IndirectGotoStmtClass: 870 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 871 872 case Stmt::LabelStmtClass: 873 return VisitLabelStmt(cast<LabelStmt>(S)); 874 875 case Stmt::MemberExprClass: 876 return VisitMemberExpr(cast<MemberExpr>(S), asc); 877 878 case Stmt::ObjCAtCatchStmtClass: 879 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 880 881 case Stmt::ObjCAtSynchronizedStmtClass: 882 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 883 884 case Stmt::ObjCAtThrowStmtClass: 885 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 886 887 case Stmt::ObjCAtTryStmtClass: 888 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 889 890 case Stmt::ObjCForCollectionStmtClass: 891 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 892 893 case Stmt::ParenExprClass: 894 S = cast<ParenExpr>(S)->getSubExpr(); 895 goto tryAgain; 896 897 case Stmt::NullStmtClass: 898 return Block; 899 900 case Stmt::ReturnStmtClass: 901 return VisitReturnStmt(cast<ReturnStmt>(S)); 902 903 case Stmt::SizeOfAlignOfExprClass: 904 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 905 906 case Stmt::StmtExprClass: 907 return VisitStmtExpr(cast<StmtExpr>(S), asc); 908 909 case Stmt::SwitchStmtClass: 910 return VisitSwitchStmt(cast<SwitchStmt>(S)); 911 912 case Stmt::UnaryOperatorClass: 913 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 914 915 case Stmt::WhileStmtClass: 916 return VisitWhileStmt(cast<WhileStmt>(S)); 917 } 918} 919 920CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 921 if (asc.alwaysAdd()) { 922 autoCreateBlock(); 923 appendStmt(Block, S, asc); 924 } 925 926 return VisitChildren(S); 927} 928 929/// VisitChildren - Visit the children of a Stmt. 930CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 931 CFGBlock *B = Block; 932 for (Stmt::child_range I = Terminator->children(); I; ++I) { 933 if (*I) B = Visit(*I); 934 } 935 return B; 936} 937 938CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 939 AddStmtChoice asc) { 940 AddressTakenLabels.insert(A->getLabel()); 941 942 if (asc.alwaysAdd()) { 943 autoCreateBlock(); 944 appendStmt(Block, A, asc); 945 } 946 947 return Block; 948} 949 950CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 951 AddStmtChoice asc) { 952 if (asc.alwaysAdd()) { 953 autoCreateBlock(); 954 appendStmt(Block, U, asc); 955 } 956 957 return Visit(U->getSubExpr(), AddStmtChoice()); 958} 959 960CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 961 AddStmtChoice asc) { 962 if (B->isLogicalOp()) { // && or || 963 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 964 appendStmt(ConfluenceBlock, B, asc); 965 966 if (badCFG) 967 return 0; 968 969 // create the block evaluating the LHS 970 CFGBlock* LHSBlock = createBlock(false); 971 LHSBlock->setTerminator(B); 972 973 // create the block evaluating the RHS 974 Succ = ConfluenceBlock; 975 Block = NULL; 976 CFGBlock* RHSBlock = addStmt(B->getRHS()); 977 978 if (RHSBlock) { 979 if (badCFG) 980 return 0; 981 } else { 982 // Create an empty block for cases where the RHS doesn't require 983 // any explicit statements in the CFG. 984 RHSBlock = createBlock(); 985 } 986 987 // See if this is a known constant. 988 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 989 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 990 KnownVal.negate(); 991 992 // Now link the LHSBlock with RHSBlock. 993 if (B->getOpcode() == BO_LOr) { 994 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 995 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 996 } else { 997 assert(B->getOpcode() == BO_LAnd); 998 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 999 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1000 } 1001 1002 // Generate the blocks for evaluating the LHS. 1003 Block = LHSBlock; 1004 return addStmt(B->getLHS()); 1005 } 1006 1007 if (B->getOpcode() == BO_Comma) { // , 1008 autoCreateBlock(); 1009 appendStmt(Block, B, asc); 1010 addStmt(B->getRHS()); 1011 return addStmt(B->getLHS()); 1012 } 1013 1014 if (B->isAssignmentOp()) { 1015 if (asc.alwaysAdd()) { 1016 autoCreateBlock(); 1017 appendStmt(Block, B, asc); 1018 } 1019 Visit(B->getLHS()); 1020 return Visit(B->getRHS()); 1021 } 1022 1023 if (asc.alwaysAdd()) { 1024 autoCreateBlock(); 1025 appendStmt(Block, B, asc); 1026 } 1027 1028 CFGBlock *RBlock = Visit(B->getRHS()); 1029 CFGBlock *LBlock = Visit(B->getLHS()); 1030 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1031 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1032 // return RBlock. Otherwise we'll incorrectly return NULL. 1033 return (LBlock ? LBlock : RBlock); 1034} 1035 1036CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1037 if (asc.alwaysAdd()) { 1038 autoCreateBlock(); 1039 appendStmt(Block, E, asc); 1040 } 1041 return Block; 1042} 1043 1044CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1045 // "break" is a control-flow statement. Thus we stop processing the current 1046 // block. 1047 if (badCFG) 1048 return 0; 1049 1050 // Now create a new block that ends with the break statement. 1051 Block = createBlock(false); 1052 Block->setTerminator(B); 1053 1054 // If there is no target for the break, then we are looking at an incomplete 1055 // AST. This means that the CFG cannot be constructed. 1056 if (BreakJumpTarget.block) { 1057 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1058 addSuccessor(Block, BreakJumpTarget.block); 1059 } else 1060 badCFG = true; 1061 1062 1063 return Block; 1064} 1065 1066static bool CanThrow(Expr *E) { 1067 QualType Ty = E->getType(); 1068 if (Ty->isFunctionPointerType()) 1069 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1070 else if (Ty->isBlockPointerType()) 1071 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1072 1073 const FunctionType *FT = Ty->getAs<FunctionType>(); 1074 if (FT) { 1075 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1076 if (Proto->hasEmptyExceptionSpec()) 1077 return false; 1078 } 1079 return true; 1080} 1081 1082CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1083 // If this is a call to a no-return function, this stops the block here. 1084 bool NoReturn = false; 1085 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 1086 NoReturn = true; 1087 } 1088 1089 bool AddEHEdge = false; 1090 1091 // Languages without exceptions are assumed to not throw. 1092 if (Context->getLangOptions().areExceptionsEnabled()) { 1093 if (BuildOpts.AddEHEdges) 1094 AddEHEdge = true; 1095 } 1096 1097 if (FunctionDecl *FD = C->getDirectCallee()) { 1098 if (FD->hasAttr<NoReturnAttr>()) 1099 NoReturn = true; 1100 if (FD->hasAttr<NoThrowAttr>()) 1101 AddEHEdge = false; 1102 } 1103 1104 if (!CanThrow(C->getCallee())) 1105 AddEHEdge = false; 1106 1107 if (!NoReturn && !AddEHEdge) 1108 return VisitStmt(C, asc.withAlwaysAdd(true)); 1109 1110 if (Block) { 1111 Succ = Block; 1112 if (badCFG) 1113 return 0; 1114 } 1115 1116 Block = createBlock(!NoReturn); 1117 appendStmt(Block, C, asc); 1118 1119 if (NoReturn) { 1120 // Wire this to the exit block directly. 1121 addSuccessor(Block, &cfg->getExit()); 1122 } 1123 if (AddEHEdge) { 1124 // Add exceptional edges. 1125 if (TryTerminatedBlock) 1126 addSuccessor(Block, TryTerminatedBlock); 1127 else 1128 addSuccessor(Block, &cfg->getExit()); 1129 } 1130 1131 return VisitChildren(C); 1132} 1133 1134CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1135 AddStmtChoice asc) { 1136 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1137 appendStmt(ConfluenceBlock, C, asc); 1138 if (badCFG) 1139 return 0; 1140 1141 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1142 Succ = ConfluenceBlock; 1143 Block = NULL; 1144 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1145 if (badCFG) 1146 return 0; 1147 1148 Succ = ConfluenceBlock; 1149 Block = NULL; 1150 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1151 if (badCFG) 1152 return 0; 1153 1154 Block = createBlock(false); 1155 // See if this is a known constant. 1156 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1157 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1158 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1159 Block->setTerminator(C); 1160 return addStmt(C->getCond()); 1161} 1162 1163 1164CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1165 addLocalScopeAndDtors(C); 1166 CFGBlock* LastBlock = Block; 1167 1168 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1169 I != E; ++I ) { 1170 // If we hit a segment of code just containing ';' (NullStmts), we can 1171 // get a null block back. In such cases, just use the LastBlock 1172 if (CFGBlock *newBlock = addStmt(*I)) 1173 LastBlock = newBlock; 1174 1175 if (badCFG) 1176 return NULL; 1177 } 1178 1179 return LastBlock; 1180} 1181 1182CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1183 AddStmtChoice asc) { 1184 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1185 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1186 1187 // Create the confluence block that will "merge" the results of the ternary 1188 // expression. 1189 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1190 appendStmt(ConfluenceBlock, C, asc); 1191 if (badCFG) 1192 return 0; 1193 1194 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1195 1196 // Create a block for the LHS expression if there is an LHS expression. A 1197 // GCC extension allows LHS to be NULL, causing the condition to be the 1198 // value that is returned instead. 1199 // e.g: x ?: y is shorthand for: x ? x : y; 1200 Succ = ConfluenceBlock; 1201 Block = NULL; 1202 CFGBlock* LHSBlock = 0; 1203 const Expr *trueExpr = C->getTrueExpr(); 1204 if (trueExpr != opaqueValue) { 1205 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1206 if (badCFG) 1207 return 0; 1208 Block = NULL; 1209 } 1210 1211 // Create the block for the RHS expression. 1212 Succ = ConfluenceBlock; 1213 CFGBlock* RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1214 if (badCFG) 1215 return 0; 1216 1217 // Create the block that will contain the condition. 1218 Block = createBlock(false); 1219 1220 // See if this is a known constant. 1221 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1222 if (LHSBlock) 1223 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1224 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1225 Block->setTerminator(C); 1226 Expr *condExpr = C->getCond(); 1227 1228 CFGBlock *result = 0; 1229 1230 // Run the condition expression if it's not trivially expressed in 1231 // terms of the opaque value (or if there is no opaque value). 1232 if (condExpr != opaqueValue) result = addStmt(condExpr); 1233 1234 // Before that, run the common subexpression if there was one. 1235 // At least one of this or the above will be run. 1236 if (opaqueValue) result = addStmt(BCO->getCommon()); 1237 1238 return result; 1239} 1240 1241CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1242 if (DS->isSingleDecl()) 1243 return VisitDeclSubExpr(DS); 1244 1245 CFGBlock *B = 0; 1246 1247 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1248 typedef llvm::SmallVector<Decl*,10> BufTy; 1249 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1250 1251 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1252 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1253 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1254 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1255 1256 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1257 // automatically freed with the CFG. 1258 DeclGroupRef DG(*I); 1259 Decl *D = *I; 1260 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1261 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1262 1263 // Append the fake DeclStmt to block. 1264 B = VisitDeclSubExpr(DSNew); 1265 } 1266 1267 return B; 1268} 1269 1270/// VisitDeclSubExpr - Utility method to add block-level expressions for 1271/// DeclStmts and initializers in them. 1272CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1273 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1274 1275 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1276 1277 if (!VD) { 1278 autoCreateBlock(); 1279 appendStmt(Block, DS); 1280 return Block; 1281 } 1282 1283 bool IsReference = false; 1284 bool HasTemporaries = false; 1285 1286 // Destructors of temporaries in initialization expression should be called 1287 // after initialization finishes. 1288 Expr *Init = VD->getInit(); 1289 if (Init) { 1290 IsReference = VD->getType()->isReferenceType(); 1291 HasTemporaries = isa<ExprWithCleanups>(Init); 1292 1293 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1294 // Generate destructors for temporaries in initialization expression. 1295 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1296 IsReference); 1297 } 1298 } 1299 1300 autoCreateBlock(); 1301 appendStmt(Block, DS); 1302 1303 if (Init) { 1304 if (HasTemporaries) 1305 // For expression with temporaries go directly to subexpression to omit 1306 // generating destructors for the second time. 1307 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1308 else 1309 Visit(Init); 1310 } 1311 1312 // If the type of VD is a VLA, then we must process its size expressions. 1313 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1314 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1315 Block = addStmt(VA->getSizeExpr()); 1316 1317 // Remove variable from local scope. 1318 if (ScopePos && VD == *ScopePos) 1319 ++ScopePos; 1320 1321 return Block; 1322} 1323 1324CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1325 // We may see an if statement in the middle of a basic block, or it may be the 1326 // first statement we are processing. In either case, we create a new basic 1327 // block. First, we create the blocks for the then...else statements, and 1328 // then we create the block containing the if statement. If we were in the 1329 // middle of a block, we stop processing that block. That block is then the 1330 // implicit successor for the "then" and "else" clauses. 1331 1332 // Save local scope position because in case of condition variable ScopePos 1333 // won't be restored when traversing AST. 1334 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1335 1336 // Create local scope for possible condition variable. 1337 // Store scope position. Add implicit destructor. 1338 if (VarDecl* VD = I->getConditionVariable()) { 1339 LocalScope::const_iterator BeginScopePos = ScopePos; 1340 addLocalScopeForVarDecl(VD); 1341 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1342 } 1343 1344 // The block we were proccessing is now finished. Make it the successor 1345 // block. 1346 if (Block) { 1347 Succ = Block; 1348 if (badCFG) 1349 return 0; 1350 } 1351 1352 // Process the false branch. 1353 CFGBlock* ElseBlock = Succ; 1354 1355 if (Stmt* Else = I->getElse()) { 1356 SaveAndRestore<CFGBlock*> sv(Succ); 1357 1358 // NULL out Block so that the recursive call to Visit will 1359 // create a new basic block. 1360 Block = NULL; 1361 1362 // If branch is not a compound statement create implicit scope 1363 // and add destructors. 1364 if (!isa<CompoundStmt>(Else)) 1365 addLocalScopeAndDtors(Else); 1366 1367 ElseBlock = addStmt(Else); 1368 1369 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1370 ElseBlock = sv.get(); 1371 else if (Block) { 1372 if (badCFG) 1373 return 0; 1374 } 1375 } 1376 1377 // Process the true branch. 1378 CFGBlock* ThenBlock; 1379 { 1380 Stmt* Then = I->getThen(); 1381 assert(Then); 1382 SaveAndRestore<CFGBlock*> sv(Succ); 1383 Block = NULL; 1384 1385 // If branch is not a compound statement create implicit scope 1386 // and add destructors. 1387 if (!isa<CompoundStmt>(Then)) 1388 addLocalScopeAndDtors(Then); 1389 1390 ThenBlock = addStmt(Then); 1391 1392 if (!ThenBlock) { 1393 // We can reach here if the "then" body has all NullStmts. 1394 // Create an empty block so we can distinguish between true and false 1395 // branches in path-sensitive analyses. 1396 ThenBlock = createBlock(false); 1397 addSuccessor(ThenBlock, sv.get()); 1398 } else if (Block) { 1399 if (badCFG) 1400 return 0; 1401 } 1402 } 1403 1404 // Now create a new block containing the if statement. 1405 Block = createBlock(false); 1406 1407 // Set the terminator of the new block to the If statement. 1408 Block->setTerminator(I); 1409 1410 // See if this is a known constant. 1411 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1412 1413 // Now add the successors. 1414 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1415 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1416 1417 // Add the condition as the last statement in the new block. This may create 1418 // new blocks as the condition may contain control-flow. Any newly created 1419 // blocks will be pointed to be "Block". 1420 Block = addStmt(I->getCond()); 1421 1422 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1423 // and the condition variable initialization to the CFG. 1424 if (VarDecl *VD = I->getConditionVariable()) { 1425 if (Expr *Init = VD->getInit()) { 1426 autoCreateBlock(); 1427 appendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1428 addStmt(Init); 1429 } 1430 } 1431 1432 return Block; 1433} 1434 1435 1436CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1437 // If we were in the middle of a block we stop processing that block. 1438 // 1439 // NOTE: If a "return" appears in the middle of a block, this means that the 1440 // code afterwards is DEAD (unreachable). We still keep a basic block 1441 // for that code; a simple "mark-and-sweep" from the entry block will be 1442 // able to report such dead blocks. 1443 1444 // Create the new block. 1445 Block = createBlock(false); 1446 1447 // The Exit block is the only successor. 1448 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1449 addSuccessor(Block, &cfg->getExit()); 1450 1451 // Add the return statement to the block. This may create new blocks if R 1452 // contains control-flow (short-circuit operations). 1453 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1454} 1455 1456CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1457 // Get the block of the labeled statement. Add it to our map. 1458 addStmt(L->getSubStmt()); 1459 CFGBlock *LabelBlock = Block; 1460 1461 if (!LabelBlock) // This can happen when the body is empty, i.e. 1462 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1463 1464 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1465 "label already in map"); 1466 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1467 1468 // Labels partition blocks, so this is the end of the basic block we were 1469 // processing (L is the block's label). Because this is label (and we have 1470 // already processed the substatement) there is no extra control-flow to worry 1471 // about. 1472 LabelBlock->setLabel(L); 1473 if (badCFG) 1474 return 0; 1475 1476 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1477 Block = NULL; 1478 1479 // This block is now the implicit successor of other blocks. 1480 Succ = LabelBlock; 1481 1482 return LabelBlock; 1483} 1484 1485CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1486 // Goto is a control-flow statement. Thus we stop processing the current 1487 // block and create a new one. 1488 1489 Block = createBlock(false); 1490 Block->setTerminator(G); 1491 1492 // If we already know the mapping to the label block add the successor now. 1493 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1494 1495 if (I == LabelMap.end()) 1496 // We will need to backpatch this block later. 1497 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1498 else { 1499 JumpTarget JT = I->second; 1500 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1501 addSuccessor(Block, JT.block); 1502 } 1503 1504 return Block; 1505} 1506 1507CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1508 CFGBlock* LoopSuccessor = NULL; 1509 1510 // Save local scope position because in case of condition variable ScopePos 1511 // won't be restored when traversing AST. 1512 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1513 1514 // Create local scope for init statement and possible condition variable. 1515 // Add destructor for init statement and condition variable. 1516 // Store scope position for continue statement. 1517 if (Stmt* Init = F->getInit()) 1518 addLocalScopeForStmt(Init); 1519 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1520 1521 if (VarDecl* VD = F->getConditionVariable()) 1522 addLocalScopeForVarDecl(VD); 1523 LocalScope::const_iterator ContinueScopePos = ScopePos; 1524 1525 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1526 1527 // "for" is a control-flow statement. Thus we stop processing the current 1528 // block. 1529 if (Block) { 1530 if (badCFG) 1531 return 0; 1532 LoopSuccessor = Block; 1533 } else 1534 LoopSuccessor = Succ; 1535 1536 // Save the current value for the break targets. 1537 // All breaks should go to the code following the loop. 1538 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1539 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1540 1541 // Because of short-circuit evaluation, the condition of the loop can span 1542 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1543 // evaluate the condition. 1544 CFGBlock* ExitConditionBlock = createBlock(false); 1545 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1546 1547 // Set the terminator for the "exit" condition block. 1548 ExitConditionBlock->setTerminator(F); 1549 1550 // Now add the actual condition to the condition block. Because the condition 1551 // itself may contain control-flow, new blocks may be created. 1552 if (Stmt* C = F->getCond()) { 1553 Block = ExitConditionBlock; 1554 EntryConditionBlock = addStmt(C); 1555 if (badCFG) 1556 return 0; 1557 assert(Block == EntryConditionBlock || 1558 (Block == 0 && EntryConditionBlock == Succ)); 1559 1560 // If this block contains a condition variable, add both the condition 1561 // variable and initializer to the CFG. 1562 if (VarDecl *VD = F->getConditionVariable()) { 1563 if (Expr *Init = VD->getInit()) { 1564 autoCreateBlock(); 1565 appendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1566 EntryConditionBlock = addStmt(Init); 1567 assert(Block == EntryConditionBlock); 1568 } 1569 } 1570 1571 if (Block) { 1572 if (badCFG) 1573 return 0; 1574 } 1575 } 1576 1577 // The condition block is the implicit successor for the loop body as well as 1578 // any code above the loop. 1579 Succ = EntryConditionBlock; 1580 1581 // See if this is a known constant. 1582 TryResult KnownVal(true); 1583 1584 if (F->getCond()) 1585 KnownVal = tryEvaluateBool(F->getCond()); 1586 1587 // Now create the loop body. 1588 { 1589 assert(F->getBody()); 1590 1591 // Save the current values for Block, Succ, and continue targets. 1592 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1593 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1594 1595 // Create a new block to contain the (bottom) of the loop body. 1596 Block = NULL; 1597 1598 // Loop body should end with destructor of Condition variable (if any). 1599 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1600 1601 if (Stmt* I = F->getInc()) { 1602 // Generate increment code in its own basic block. This is the target of 1603 // continue statements. 1604 Succ = addStmt(I); 1605 } else { 1606 // No increment code. Create a special, empty, block that is used as the 1607 // target block for "looping back" to the start of the loop. 1608 assert(Succ == EntryConditionBlock); 1609 Succ = Block ? Block : createBlock(); 1610 } 1611 1612 // Finish up the increment (or empty) block if it hasn't been already. 1613 if (Block) { 1614 assert(Block == Succ); 1615 if (badCFG) 1616 return 0; 1617 Block = 0; 1618 } 1619 1620 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1621 1622 // The starting block for the loop increment is the block that should 1623 // represent the 'loop target' for looping back to the start of the loop. 1624 ContinueJumpTarget.block->setLoopTarget(F); 1625 1626 // If body is not a compound statement create implicit scope 1627 // and add destructors. 1628 if (!isa<CompoundStmt>(F->getBody())) 1629 addLocalScopeAndDtors(F->getBody()); 1630 1631 // Now populate the body block, and in the process create new blocks as we 1632 // walk the body of the loop. 1633 CFGBlock* BodyBlock = addStmt(F->getBody()); 1634 1635 if (!BodyBlock) 1636 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1637 else if (badCFG) 1638 return 0; 1639 1640 // This new body block is a successor to our "exit" condition block. 1641 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1642 } 1643 1644 // Link up the condition block with the code that follows the loop. (the 1645 // false branch). 1646 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1647 1648 // If the loop contains initialization, create a new block for those 1649 // statements. This block can also contain statements that precede the loop. 1650 if (Stmt* I = F->getInit()) { 1651 Block = createBlock(); 1652 return addStmt(I); 1653 } 1654 1655 // There is no loop initialization. We are thus basically a while loop. 1656 // NULL out Block to force lazy block construction. 1657 Block = NULL; 1658 Succ = EntryConditionBlock; 1659 return EntryConditionBlock; 1660} 1661 1662CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1663 if (asc.alwaysAdd()) { 1664 autoCreateBlock(); 1665 appendStmt(Block, M, asc); 1666 } 1667 return Visit(M->getBase()); 1668} 1669 1670CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1671 // Objective-C fast enumeration 'for' statements: 1672 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1673 // 1674 // for ( Type newVariable in collection_expression ) { statements } 1675 // 1676 // becomes: 1677 // 1678 // prologue: 1679 // 1. collection_expression 1680 // T. jump to loop_entry 1681 // loop_entry: 1682 // 1. side-effects of element expression 1683 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1684 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1685 // TB: 1686 // statements 1687 // T. jump to loop_entry 1688 // FB: 1689 // what comes after 1690 // 1691 // and 1692 // 1693 // Type existingItem; 1694 // for ( existingItem in expression ) { statements } 1695 // 1696 // becomes: 1697 // 1698 // the same with newVariable replaced with existingItem; the binding works 1699 // the same except that for one ObjCForCollectionStmt::getElement() returns 1700 // a DeclStmt and the other returns a DeclRefExpr. 1701 // 1702 1703 CFGBlock* LoopSuccessor = 0; 1704 1705 if (Block) { 1706 if (badCFG) 1707 return 0; 1708 LoopSuccessor = Block; 1709 Block = 0; 1710 } else 1711 LoopSuccessor = Succ; 1712 1713 // Build the condition blocks. 1714 CFGBlock* ExitConditionBlock = createBlock(false); 1715 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1716 1717 // Set the terminator for the "exit" condition block. 1718 ExitConditionBlock->setTerminator(S); 1719 1720 // The last statement in the block should be the ObjCForCollectionStmt, which 1721 // performs the actual binding to 'element' and determines if there are any 1722 // more items in the collection. 1723 appendStmt(ExitConditionBlock, S); 1724 Block = ExitConditionBlock; 1725 1726 // Walk the 'element' expression to see if there are any side-effects. We 1727 // generate new blocks as necesary. We DON'T add the statement by default to 1728 // the CFG unless it contains control-flow. 1729 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1730 if (Block) { 1731 if (badCFG) 1732 return 0; 1733 Block = 0; 1734 } 1735 1736 // The condition block is the implicit successor for the loop body as well as 1737 // any code above the loop. 1738 Succ = EntryConditionBlock; 1739 1740 // Now create the true branch. 1741 { 1742 // Save the current values for Succ, continue and break targets. 1743 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1744 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1745 save_break(BreakJumpTarget); 1746 1747 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1748 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1749 1750 CFGBlock* BodyBlock = addStmt(S->getBody()); 1751 1752 if (!BodyBlock) 1753 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1754 else if (Block) { 1755 if (badCFG) 1756 return 0; 1757 } 1758 1759 // This new body block is a successor to our "exit" condition block. 1760 addSuccessor(ExitConditionBlock, BodyBlock); 1761 } 1762 1763 // Link up the condition block with the code that follows the loop. 1764 // (the false branch). 1765 addSuccessor(ExitConditionBlock, LoopSuccessor); 1766 1767 // Now create a prologue block to contain the collection expression. 1768 Block = createBlock(); 1769 return addStmt(S->getCollection()); 1770} 1771 1772CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1773 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1774 1775 // Inline the body. 1776 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1777 1778 // The sync body starts its own basic block. This makes it a little easier 1779 // for diagnostic clients. 1780 if (SyncBlock) { 1781 if (badCFG) 1782 return 0; 1783 1784 Block = 0; 1785 Succ = SyncBlock; 1786 } 1787 1788 // Add the @synchronized to the CFG. 1789 autoCreateBlock(); 1790 appendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1791 1792 // Inline the sync expression. 1793 return addStmt(S->getSynchExpr()); 1794} 1795 1796CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1797 // FIXME 1798 return NYS(); 1799} 1800 1801CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1802 CFGBlock* LoopSuccessor = NULL; 1803 1804 // Save local scope position because in case of condition variable ScopePos 1805 // won't be restored when traversing AST. 1806 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1807 1808 // Create local scope for possible condition variable. 1809 // Store scope position for continue statement. 1810 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1811 if (VarDecl* VD = W->getConditionVariable()) { 1812 addLocalScopeForVarDecl(VD); 1813 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1814 } 1815 1816 // "while" is a control-flow statement. Thus we stop processing the current 1817 // block. 1818 if (Block) { 1819 if (badCFG) 1820 return 0; 1821 LoopSuccessor = Block; 1822 } else 1823 LoopSuccessor = Succ; 1824 1825 // Because of short-circuit evaluation, the condition of the loop can span 1826 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1827 // evaluate the condition. 1828 CFGBlock* ExitConditionBlock = createBlock(false); 1829 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1830 1831 // Set the terminator for the "exit" condition block. 1832 ExitConditionBlock->setTerminator(W); 1833 1834 // Now add the actual condition to the condition block. Because the condition 1835 // itself may contain control-flow, new blocks may be created. Thus we update 1836 // "Succ" after adding the condition. 1837 if (Stmt* C = W->getCond()) { 1838 Block = ExitConditionBlock; 1839 EntryConditionBlock = addStmt(C); 1840 // The condition might finish the current 'Block'. 1841 Block = EntryConditionBlock; 1842 1843 // If this block contains a condition variable, add both the condition 1844 // variable and initializer to the CFG. 1845 if (VarDecl *VD = W->getConditionVariable()) { 1846 if (Expr *Init = VD->getInit()) { 1847 autoCreateBlock(); 1848 appendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1849 EntryConditionBlock = addStmt(Init); 1850 assert(Block == EntryConditionBlock); 1851 } 1852 } 1853 1854 if (Block) { 1855 if (badCFG) 1856 return 0; 1857 } 1858 } 1859 1860 // The condition block is the implicit successor for the loop body as well as 1861 // any code above the loop. 1862 Succ = EntryConditionBlock; 1863 1864 // See if this is a known constant. 1865 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1866 1867 // Process the loop body. 1868 { 1869 assert(W->getBody()); 1870 1871 // Save the current values for Block, Succ, and continue and break targets 1872 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1873 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1874 save_break(BreakJumpTarget); 1875 1876 // Create an empty block to represent the transition block for looping back 1877 // to the head of the loop. 1878 Block = 0; 1879 assert(Succ == EntryConditionBlock); 1880 Succ = createBlock(); 1881 Succ->setLoopTarget(W); 1882 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1883 1884 // All breaks should go to the code following the loop. 1885 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1886 1887 // NULL out Block to force lazy instantiation of blocks for the body. 1888 Block = NULL; 1889 1890 // Loop body should end with destructor of Condition variable (if any). 1891 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1892 1893 // If body is not a compound statement create implicit scope 1894 // and add destructors. 1895 if (!isa<CompoundStmt>(W->getBody())) 1896 addLocalScopeAndDtors(W->getBody()); 1897 1898 // Create the body. The returned block is the entry to the loop body. 1899 CFGBlock* BodyBlock = addStmt(W->getBody()); 1900 1901 if (!BodyBlock) 1902 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 1903 else if (Block) { 1904 if (badCFG) 1905 return 0; 1906 } 1907 1908 // Add the loop body entry as a successor to the condition. 1909 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1910 } 1911 1912 // Link up the condition block with the code that follows the loop. (the 1913 // false branch). 1914 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1915 1916 // There can be no more statements in the condition block since we loop back 1917 // to this block. NULL out Block to force lazy creation of another block. 1918 Block = NULL; 1919 1920 // Return the condition block, which is the dominating block for the loop. 1921 Succ = EntryConditionBlock; 1922 return EntryConditionBlock; 1923} 1924 1925 1926CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1927 // FIXME: For now we pretend that @catch and the code it contains does not 1928 // exit. 1929 return Block; 1930} 1931 1932CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1933 // FIXME: This isn't complete. We basically treat @throw like a return 1934 // statement. 1935 1936 // If we were in the middle of a block we stop processing that block. 1937 if (badCFG) 1938 return 0; 1939 1940 // Create the new block. 1941 Block = createBlock(false); 1942 1943 // The Exit block is the only successor. 1944 addSuccessor(Block, &cfg->getExit()); 1945 1946 // Add the statement to the block. This may create new blocks if S contains 1947 // control-flow (short-circuit operations). 1948 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1949} 1950 1951CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1952 // If we were in the middle of a block we stop processing that block. 1953 if (badCFG) 1954 return 0; 1955 1956 // Create the new block. 1957 Block = createBlock(false); 1958 1959 if (TryTerminatedBlock) 1960 // The current try statement is the only successor. 1961 addSuccessor(Block, TryTerminatedBlock); 1962 else 1963 // otherwise the Exit block is the only successor. 1964 addSuccessor(Block, &cfg->getExit()); 1965 1966 // Add the statement to the block. This may create new blocks if S contains 1967 // control-flow (short-circuit operations). 1968 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1969} 1970 1971CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1972 CFGBlock* LoopSuccessor = NULL; 1973 1974 // "do...while" is a control-flow statement. Thus we stop processing the 1975 // current block. 1976 if (Block) { 1977 if (badCFG) 1978 return 0; 1979 LoopSuccessor = Block; 1980 } else 1981 LoopSuccessor = Succ; 1982 1983 // Because of short-circuit evaluation, the condition of the loop can span 1984 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1985 // evaluate the condition. 1986 CFGBlock* ExitConditionBlock = createBlock(false); 1987 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1988 1989 // Set the terminator for the "exit" condition block. 1990 ExitConditionBlock->setTerminator(D); 1991 1992 // Now add the actual condition to the condition block. Because the condition 1993 // itself may contain control-flow, new blocks may be created. 1994 if (Stmt* C = D->getCond()) { 1995 Block = ExitConditionBlock; 1996 EntryConditionBlock = addStmt(C); 1997 if (Block) { 1998 if (badCFG) 1999 return 0; 2000 } 2001 } 2002 2003 // The condition block is the implicit successor for the loop body. 2004 Succ = EntryConditionBlock; 2005 2006 // See if this is a known constant. 2007 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2008 2009 // Process the loop body. 2010 CFGBlock* BodyBlock = NULL; 2011 { 2012 assert(D->getBody()); 2013 2014 // Save the current values for Block, Succ, and continue and break targets 2015 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2016 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2017 save_break(BreakJumpTarget); 2018 2019 // All continues within this loop should go to the condition block 2020 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2021 2022 // All breaks should go to the code following the loop. 2023 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2024 2025 // NULL out Block to force lazy instantiation of blocks for the body. 2026 Block = NULL; 2027 2028 // If body is not a compound statement create implicit scope 2029 // and add destructors. 2030 if (!isa<CompoundStmt>(D->getBody())) 2031 addLocalScopeAndDtors(D->getBody()); 2032 2033 // Create the body. The returned block is the entry to the loop body. 2034 BodyBlock = addStmt(D->getBody()); 2035 2036 if (!BodyBlock) 2037 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2038 else if (Block) { 2039 if (badCFG) 2040 return 0; 2041 } 2042 2043 if (!KnownVal.isFalse()) { 2044 // Add an intermediate block between the BodyBlock and the 2045 // ExitConditionBlock to represent the "loop back" transition. Create an 2046 // empty block to represent the transition block for looping back to the 2047 // head of the loop. 2048 // FIXME: Can we do this more efficiently without adding another block? 2049 Block = NULL; 2050 Succ = BodyBlock; 2051 CFGBlock *LoopBackBlock = createBlock(); 2052 LoopBackBlock->setLoopTarget(D); 2053 2054 // Add the loop body entry as a successor to the condition. 2055 addSuccessor(ExitConditionBlock, LoopBackBlock); 2056 } 2057 else 2058 addSuccessor(ExitConditionBlock, NULL); 2059 } 2060 2061 // Link up the condition block with the code that follows the loop. 2062 // (the false branch). 2063 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2064 2065 // There can be no more statements in the body block(s) since we loop back to 2066 // the body. NULL out Block to force lazy creation of another block. 2067 Block = NULL; 2068 2069 // Return the loop body, which is the dominating block for the loop. 2070 Succ = BodyBlock; 2071 return BodyBlock; 2072} 2073 2074CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2075 // "continue" is a control-flow statement. Thus we stop processing the 2076 // current block. 2077 if (badCFG) 2078 return 0; 2079 2080 // Now create a new block that ends with the continue statement. 2081 Block = createBlock(false); 2082 Block->setTerminator(C); 2083 2084 // If there is no target for the continue, then we are looking at an 2085 // incomplete AST. This means the CFG cannot be constructed. 2086 if (ContinueJumpTarget.block) { 2087 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2088 addSuccessor(Block, ContinueJumpTarget.block); 2089 } else 2090 badCFG = true; 2091 2092 return Block; 2093} 2094 2095CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 2096 AddStmtChoice asc) { 2097 2098 if (asc.alwaysAdd()) { 2099 autoCreateBlock(); 2100 appendStmt(Block, E); 2101 } 2102 2103 // VLA types have expressions that must be evaluated. 2104 if (E->isArgumentType()) { 2105 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2106 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2107 addStmt(VA->getSizeExpr()); 2108 } 2109 2110 return Block; 2111} 2112 2113/// VisitStmtExpr - Utility method to handle (nested) statement 2114/// expressions (a GCC extension). 2115CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2116 if (asc.alwaysAdd()) { 2117 autoCreateBlock(); 2118 appendStmt(Block, SE); 2119 } 2120 return VisitCompoundStmt(SE->getSubStmt()); 2121} 2122 2123CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2124 // "switch" is a control-flow statement. Thus we stop processing the current 2125 // block. 2126 CFGBlock* SwitchSuccessor = NULL; 2127 2128 // Save local scope position because in case of condition variable ScopePos 2129 // won't be restored when traversing AST. 2130 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2131 2132 // Create local scope for possible condition variable. 2133 // Store scope position. Add implicit destructor. 2134 if (VarDecl* VD = Terminator->getConditionVariable()) { 2135 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2136 addLocalScopeForVarDecl(VD); 2137 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2138 } 2139 2140 if (Block) { 2141 if (badCFG) 2142 return 0; 2143 SwitchSuccessor = Block; 2144 } else SwitchSuccessor = Succ; 2145 2146 // Save the current "switch" context. 2147 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2148 save_default(DefaultCaseBlock); 2149 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2150 2151 // Set the "default" case to be the block after the switch statement. If the 2152 // switch statement contains a "default:", this value will be overwritten with 2153 // the block for that code. 2154 DefaultCaseBlock = SwitchSuccessor; 2155 2156 // Create a new block that will contain the switch statement. 2157 SwitchTerminatedBlock = createBlock(false); 2158 2159 // Now process the switch body. The code after the switch is the implicit 2160 // successor. 2161 Succ = SwitchSuccessor; 2162 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2163 2164 // When visiting the body, the case statements should automatically get linked 2165 // up to the switch. We also don't keep a pointer to the body, since all 2166 // control-flow from the switch goes to case/default statements. 2167 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2168 Block = NULL; 2169 2170 // If body is not a compound statement create implicit scope 2171 // and add destructors. 2172 if (!isa<CompoundStmt>(Terminator->getBody())) 2173 addLocalScopeAndDtors(Terminator->getBody()); 2174 2175 addStmt(Terminator->getBody()); 2176 if (Block) { 2177 if (badCFG) 2178 return 0; 2179 } 2180 2181 // If we have no "default:" case, the default transition is to the code 2182 // following the switch body. 2183 addSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 2184 2185 // Add the terminator and condition in the switch block. 2186 SwitchTerminatedBlock->setTerminator(Terminator); 2187 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2188 Block = SwitchTerminatedBlock; 2189 Block = addStmt(Terminator->getCond()); 2190 2191 // Finally, if the SwitchStmt contains a condition variable, add both the 2192 // SwitchStmt and the condition variable initialization to the CFG. 2193 if (VarDecl *VD = Terminator->getConditionVariable()) { 2194 if (Expr *Init = VD->getInit()) { 2195 autoCreateBlock(); 2196 appendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2197 addStmt(Init); 2198 } 2199 } 2200 2201 return Block; 2202} 2203 2204CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2205 // CaseStmts are essentially labels, so they are the first statement in a 2206 // block. 2207 CFGBlock *TopBlock = 0, *LastBlock = 0; 2208 2209 if (Stmt *Sub = CS->getSubStmt()) { 2210 // For deeply nested chains of CaseStmts, instead of doing a recursion 2211 // (which can blow out the stack), manually unroll and create blocks 2212 // along the way. 2213 while (isa<CaseStmt>(Sub)) { 2214 CFGBlock *currentBlock = createBlock(false); 2215 currentBlock->setLabel(CS); 2216 2217 if (TopBlock) 2218 addSuccessor(LastBlock, currentBlock); 2219 else 2220 TopBlock = currentBlock; 2221 2222 addSuccessor(SwitchTerminatedBlock, currentBlock); 2223 LastBlock = currentBlock; 2224 2225 CS = cast<CaseStmt>(Sub); 2226 Sub = CS->getSubStmt(); 2227 } 2228 2229 addStmt(Sub); 2230 } 2231 2232 CFGBlock* CaseBlock = Block; 2233 if (!CaseBlock) 2234 CaseBlock = createBlock(); 2235 2236 // Cases statements partition blocks, so this is the top of the basic block we 2237 // were processing (the "case XXX:" is the label). 2238 CaseBlock->setLabel(CS); 2239 2240 if (badCFG) 2241 return 0; 2242 2243 // Add this block to the list of successors for the block with the switch 2244 // statement. 2245 assert(SwitchTerminatedBlock); 2246 addSuccessor(SwitchTerminatedBlock, CaseBlock); 2247 2248 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2249 Block = NULL; 2250 2251 if (TopBlock) { 2252 addSuccessor(LastBlock, CaseBlock); 2253 Succ = TopBlock; 2254 } else { 2255 // This block is now the implicit successor of other blocks. 2256 Succ = CaseBlock; 2257 } 2258 2259 return Succ; 2260} 2261 2262CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2263 if (Terminator->getSubStmt()) 2264 addStmt(Terminator->getSubStmt()); 2265 2266 DefaultCaseBlock = Block; 2267 2268 if (!DefaultCaseBlock) 2269 DefaultCaseBlock = createBlock(); 2270 2271 // Default statements partition blocks, so this is the top of the basic block 2272 // we were processing (the "default:" is the label). 2273 DefaultCaseBlock->setLabel(Terminator); 2274 2275 if (badCFG) 2276 return 0; 2277 2278 // Unlike case statements, we don't add the default block to the successors 2279 // for the switch statement immediately. This is done when we finish 2280 // processing the switch statement. This allows for the default case 2281 // (including a fall-through to the code after the switch statement) to always 2282 // be the last successor of a switch-terminated block. 2283 2284 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2285 Block = NULL; 2286 2287 // This block is now the implicit successor of other blocks. 2288 Succ = DefaultCaseBlock; 2289 2290 return DefaultCaseBlock; 2291} 2292 2293CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2294 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2295 // current block. 2296 CFGBlock* TrySuccessor = NULL; 2297 2298 if (Block) { 2299 if (badCFG) 2300 return 0; 2301 TrySuccessor = Block; 2302 } else TrySuccessor = Succ; 2303 2304 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2305 2306 // Create a new block that will contain the try statement. 2307 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2308 // Add the terminator in the try block. 2309 NewTryTerminatedBlock->setTerminator(Terminator); 2310 2311 bool HasCatchAll = false; 2312 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2313 // The code after the try is the implicit successor. 2314 Succ = TrySuccessor; 2315 CXXCatchStmt *CS = Terminator->getHandler(h); 2316 if (CS->getExceptionDecl() == 0) { 2317 HasCatchAll = true; 2318 } 2319 Block = NULL; 2320 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2321 if (CatchBlock == 0) 2322 return 0; 2323 // Add this block to the list of successors for the block with the try 2324 // statement. 2325 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2326 } 2327 if (!HasCatchAll) { 2328 if (PrevTryTerminatedBlock) 2329 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2330 else 2331 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2332 } 2333 2334 // The code after the try is the implicit successor. 2335 Succ = TrySuccessor; 2336 2337 // Save the current "try" context. 2338 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2339 TryTerminatedBlock = NewTryTerminatedBlock; 2340 2341 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2342 Block = NULL; 2343 Block = addStmt(Terminator->getTryBlock()); 2344 return Block; 2345} 2346 2347CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2348 // CXXCatchStmt are treated like labels, so they are the first statement in a 2349 // block. 2350 2351 // Save local scope position because in case of exception variable ScopePos 2352 // won't be restored when traversing AST. 2353 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2354 2355 // Create local scope for possible exception variable. 2356 // Store scope position. Add implicit destructor. 2357 if (VarDecl* VD = CS->getExceptionDecl()) { 2358 LocalScope::const_iterator BeginScopePos = ScopePos; 2359 addLocalScopeForVarDecl(VD); 2360 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2361 } 2362 2363 if (CS->getHandlerBlock()) 2364 addStmt(CS->getHandlerBlock()); 2365 2366 CFGBlock* CatchBlock = Block; 2367 if (!CatchBlock) 2368 CatchBlock = createBlock(); 2369 2370 CatchBlock->setLabel(CS); 2371 2372 if (badCFG) 2373 return 0; 2374 2375 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2376 Block = NULL; 2377 2378 return CatchBlock; 2379} 2380 2381CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2382 AddStmtChoice asc) { 2383 if (BuildOpts.AddImplicitDtors) { 2384 // If adding implicit destructors visit the full expression for adding 2385 // destructors of temporaries. 2386 VisitForTemporaryDtors(E->getSubExpr()); 2387 2388 // Full expression has to be added as CFGStmt so it will be sequenced 2389 // before destructors of it's temporaries. 2390 asc = asc.withAlwaysAdd(true); 2391 } 2392 return Visit(E->getSubExpr(), asc); 2393} 2394 2395CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2396 AddStmtChoice asc) { 2397 if (asc.alwaysAdd()) { 2398 autoCreateBlock(); 2399 appendStmt(Block, E, asc); 2400 2401 // We do not want to propagate the AlwaysAdd property. 2402 asc = asc.withAlwaysAdd(false); 2403 } 2404 return Visit(E->getSubExpr(), asc); 2405} 2406 2407CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2408 AddStmtChoice asc) { 2409 autoCreateBlock(); 2410 if (!C->isElidable()) 2411 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2412 2413 return VisitChildren(C); 2414} 2415 2416CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2417 AddStmtChoice asc) { 2418 if (asc.alwaysAdd()) { 2419 autoCreateBlock(); 2420 appendStmt(Block, E, asc); 2421 // We do not want to propagate the AlwaysAdd property. 2422 asc = asc.withAlwaysAdd(false); 2423 } 2424 return Visit(E->getSubExpr(), asc); 2425} 2426 2427CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2428 AddStmtChoice asc) { 2429 autoCreateBlock(); 2430 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2431 return VisitChildren(C); 2432} 2433 2434CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2435 AddStmtChoice asc) { 2436 autoCreateBlock(); 2437 appendStmt(Block, C, asc.withAlwaysAdd(true)); 2438 return VisitChildren(C); 2439} 2440 2441CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2442 AddStmtChoice asc) { 2443 if (asc.alwaysAdd()) { 2444 autoCreateBlock(); 2445 appendStmt(Block, E, asc); 2446 } 2447 return Visit(E->getSubExpr(), AddStmtChoice()); 2448} 2449 2450CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2451 // Lazily create the indirect-goto dispatch block if there isn't one already. 2452 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2453 2454 if (!IBlock) { 2455 IBlock = createBlock(false); 2456 cfg->setIndirectGotoBlock(IBlock); 2457 } 2458 2459 // IndirectGoto is a control-flow statement. Thus we stop processing the 2460 // current block and create a new one. 2461 if (badCFG) 2462 return 0; 2463 2464 Block = createBlock(false); 2465 Block->setTerminator(I); 2466 addSuccessor(Block, IBlock); 2467 return addStmt(I->getTarget()); 2468} 2469 2470CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2471tryAgain: 2472 if (!E) { 2473 badCFG = true; 2474 return NULL; 2475 } 2476 switch (E->getStmtClass()) { 2477 default: 2478 return VisitChildrenForTemporaryDtors(E); 2479 2480 case Stmt::BinaryOperatorClass: 2481 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2482 2483 case Stmt::CXXBindTemporaryExprClass: 2484 return VisitCXXBindTemporaryExprForTemporaryDtors( 2485 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2486 2487 case Stmt::BinaryConditionalOperatorClass: 2488 case Stmt::ConditionalOperatorClass: 2489 return VisitConditionalOperatorForTemporaryDtors( 2490 cast<AbstractConditionalOperator>(E), BindToTemporary); 2491 2492 case Stmt::ImplicitCastExprClass: 2493 // For implicit cast we want BindToTemporary to be passed further. 2494 E = cast<CastExpr>(E)->getSubExpr(); 2495 goto tryAgain; 2496 2497 case Stmt::ParenExprClass: 2498 E = cast<ParenExpr>(E)->getSubExpr(); 2499 goto tryAgain; 2500 } 2501} 2502 2503CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2504 // When visiting children for destructors we want to visit them in reverse 2505 // order. Because there's no reverse iterator for children must to reverse 2506 // them in helper vector. 2507 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2508 ChildrenVect ChildrenRev; 2509 for (Stmt::child_range I = E->children(); I; ++I) { 2510 if (*I) ChildrenRev.push_back(*I); 2511 } 2512 2513 CFGBlock *B = Block; 2514 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2515 L = ChildrenRev.rend(); I != L; ++I) { 2516 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2517 B = R; 2518 } 2519 return B; 2520} 2521 2522CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2523 if (E->isLogicalOp()) { 2524 // Destructors for temporaries in LHS expression should be called after 2525 // those for RHS expression. Even if this will unnecessarily create a block, 2526 // this block will be used at least by the full expression. 2527 autoCreateBlock(); 2528 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2529 if (badCFG) 2530 return NULL; 2531 2532 Succ = ConfluenceBlock; 2533 Block = NULL; 2534 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2535 2536 if (RHSBlock) { 2537 if (badCFG) 2538 return NULL; 2539 2540 // If RHS expression did produce destructors we need to connect created 2541 // blocks to CFG in same manner as for binary operator itself. 2542 CFGBlock *LHSBlock = createBlock(false); 2543 LHSBlock->setTerminator(CFGTerminator(E, true)); 2544 2545 // For binary operator LHS block is before RHS in list of predecessors 2546 // of ConfluenceBlock. 2547 std::reverse(ConfluenceBlock->pred_begin(), 2548 ConfluenceBlock->pred_end()); 2549 2550 // See if this is a known constant. 2551 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2552 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2553 KnownVal.negate(); 2554 2555 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2556 // itself. 2557 if (E->getOpcode() == BO_LOr) { 2558 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2559 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2560 } else { 2561 assert (E->getOpcode() == BO_LAnd); 2562 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2563 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2564 } 2565 2566 Block = LHSBlock; 2567 return LHSBlock; 2568 } 2569 2570 Block = ConfluenceBlock; 2571 return ConfluenceBlock; 2572 } 2573 2574 if (E->isAssignmentOp()) { 2575 // For assignment operator (=) LHS expression is visited 2576 // before RHS expression. For destructors visit them in reverse order. 2577 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2578 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2579 return LHSBlock ? LHSBlock : RHSBlock; 2580 } 2581 2582 // For any other binary operator RHS expression is visited before 2583 // LHS expression (order of children). For destructors visit them in reverse 2584 // order. 2585 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2586 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2587 return RHSBlock ? RHSBlock : LHSBlock; 2588} 2589 2590CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2591 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2592 // First add destructors for temporaries in subexpression. 2593 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2594 if (!BindToTemporary) { 2595 // If lifetime of temporary is not prolonged (by assigning to constant 2596 // reference) add destructor for it. 2597 autoCreateBlock(); 2598 appendTemporaryDtor(Block, E); 2599 B = Block; 2600 } 2601 return B; 2602} 2603 2604CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2605 AbstractConditionalOperator *E, bool BindToTemporary) { 2606 // First add destructors for condition expression. Even if this will 2607 // unnecessarily create a block, this block will be used at least by the full 2608 // expression. 2609 autoCreateBlock(); 2610 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2611 if (badCFG) 2612 return NULL; 2613 if (BinaryConditionalOperator *BCO 2614 = dyn_cast<BinaryConditionalOperator>(E)) { 2615 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2616 if (badCFG) 2617 return NULL; 2618 } 2619 2620 // Try to add block with destructors for LHS expression. 2621 CFGBlock *LHSBlock = NULL; 2622 Succ = ConfluenceBlock; 2623 Block = NULL; 2624 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2625 if (badCFG) 2626 return NULL; 2627 2628 // Try to add block with destructors for RHS expression; 2629 Succ = ConfluenceBlock; 2630 Block = NULL; 2631 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2632 BindToTemporary); 2633 if (badCFG) 2634 return NULL; 2635 2636 if (!RHSBlock && !LHSBlock) { 2637 // If neither LHS nor RHS expression had temporaries to destroy don't create 2638 // more blocks. 2639 Block = ConfluenceBlock; 2640 return Block; 2641 } 2642 2643 Block = createBlock(false); 2644 Block->setTerminator(CFGTerminator(E, true)); 2645 2646 // See if this is a known constant. 2647 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2648 2649 if (LHSBlock) { 2650 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2651 } else if (KnownVal.isFalse()) { 2652 addSuccessor(Block, NULL); 2653 } else { 2654 addSuccessor(Block, ConfluenceBlock); 2655 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2656 } 2657 2658 if (!RHSBlock) 2659 RHSBlock = ConfluenceBlock; 2660 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2661 2662 return Block; 2663} 2664 2665} // end anonymous namespace 2666 2667/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2668/// no successors or predecessors. If this is the first block created in the 2669/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2670CFGBlock* CFG::createBlock() { 2671 bool first_block = begin() == end(); 2672 2673 // Create the block. 2674 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2675 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2676 Blocks.push_back(Mem, BlkBVC); 2677 2678 // If this is the first block, set it as the Entry and Exit. 2679 if (first_block) 2680 Entry = Exit = &back(); 2681 2682 // Return the block. 2683 return &back(); 2684} 2685 2686/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2687/// CFG is returned to the caller. 2688CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2689 BuildOptions BO) { 2690 CFGBuilder Builder; 2691 return Builder.buildCFG(D, Statement, C, BO); 2692} 2693 2694//===----------------------------------------------------------------------===// 2695// CFG: Queries for BlkExprs. 2696//===----------------------------------------------------------------------===// 2697 2698namespace { 2699 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2700} 2701 2702static void FindSubExprAssignments(Stmt *S, 2703 llvm::SmallPtrSet<Expr*,50>& Set) { 2704 if (!S) 2705 return; 2706 2707 for (Stmt::child_range I = S->children(); I; ++I) { 2708 Stmt *child = *I; 2709 if (!child) 2710 continue; 2711 2712 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2713 if (B->isAssignmentOp()) Set.insert(B); 2714 2715 FindSubExprAssignments(child, Set); 2716 } 2717} 2718 2719static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2720 BlkExprMapTy* M = new BlkExprMapTy(); 2721 2722 // Look for assignments that are used as subexpressions. These are the only 2723 // assignments that we want to *possibly* register as a block-level 2724 // expression. Basically, if an assignment occurs both in a subexpression and 2725 // at the block-level, it is a block-level expression. 2726 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2727 2728 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2729 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2730 if (CFGStmt S = BI->getAs<CFGStmt>()) 2731 FindSubExprAssignments(S, SubExprAssignments); 2732 2733 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2734 2735 // Iterate over the statements again on identify the Expr* and Stmt* at the 2736 // block-level that are block-level expressions. 2737 2738 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2739 CFGStmt CS = BI->getAs<CFGStmt>(); 2740 if (!CS.isValid()) 2741 continue; 2742 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2743 2744 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2745 // Assignment expressions that are not nested within another 2746 // expression are really "statements" whose value is never used by 2747 // another expression. 2748 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2749 continue; 2750 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2751 // Special handling for statement expressions. The last statement in 2752 // the statement expression is also a block-level expr. 2753 const CompoundStmt* C = Terminator->getSubStmt(); 2754 if (!C->body_empty()) { 2755 unsigned x = M->size(); 2756 (*M)[C->body_back()] = x; 2757 } 2758 } 2759 2760 unsigned x = M->size(); 2761 (*M)[Exp] = x; 2762 } 2763 } 2764 2765 // Look at terminators. The condition is a block-level expression. 2766 2767 Stmt* S = (*I)->getTerminatorCondition(); 2768 2769 if (S && M->find(S) == M->end()) { 2770 unsigned x = M->size(); 2771 (*M)[S] = x; 2772 } 2773 } 2774 2775 return M; 2776} 2777 2778CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2779 assert(S != NULL); 2780 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2781 2782 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2783 BlkExprMapTy::iterator I = M->find(S); 2784 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2785} 2786 2787unsigned CFG::getNumBlkExprs() { 2788 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2789 return M->size(); 2790 2791 // We assume callers interested in the number of BlkExprs will want 2792 // the map constructed if it doesn't already exist. 2793 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2794 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2795} 2796 2797//===----------------------------------------------------------------------===// 2798// Filtered walking of the CFG. 2799//===----------------------------------------------------------------------===// 2800 2801bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2802 const CFGBlock *From, const CFGBlock *To) { 2803 2804 if (F.IgnoreDefaultsWithCoveredEnums) { 2805 // If the 'To' has no label or is labeled but the label isn't a 2806 // CaseStmt then filter this edge. 2807 if (const SwitchStmt *S = 2808 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 2809 if (S->isAllEnumCasesCovered()) { 2810 const Stmt *L = To->getLabel(); 2811 if (!L || !isa<CaseStmt>(L)) 2812 return true; 2813 } 2814 } 2815 } 2816 2817 return false; 2818} 2819 2820//===----------------------------------------------------------------------===// 2821// Cleanup: CFG dstor. 2822//===----------------------------------------------------------------------===// 2823 2824CFG::~CFG() { 2825 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2826} 2827 2828//===----------------------------------------------------------------------===// 2829// CFG pretty printing 2830//===----------------------------------------------------------------------===// 2831 2832namespace { 2833 2834class StmtPrinterHelper : public PrinterHelper { 2835 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2836 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2837 StmtMapTy StmtMap; 2838 DeclMapTy DeclMap; 2839 signed currentBlock; 2840 unsigned currentStmt; 2841 const LangOptions &LangOpts; 2842public: 2843 2844 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2845 : currentBlock(0), currentStmt(0), LangOpts(LO) { 2846 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2847 unsigned j = 1; 2848 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2849 BI != BEnd; ++BI, ++j ) { 2850 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2851 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2852 StmtMap[SE] = P; 2853 2854 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2855 DeclMap[DS->getSingleDecl()] = P; 2856 2857 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2858 if (VarDecl* VD = IS->getConditionVariable()) 2859 DeclMap[VD] = P; 2860 2861 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2862 if (VarDecl* VD = FS->getConditionVariable()) 2863 DeclMap[VD] = P; 2864 2865 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2866 if (VarDecl* VD = WS->getConditionVariable()) 2867 DeclMap[VD] = P; 2868 2869 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2870 if (VarDecl* VD = SS->getConditionVariable()) 2871 DeclMap[VD] = P; 2872 2873 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2874 if (VarDecl* VD = CS->getExceptionDecl()) 2875 DeclMap[VD] = P; 2876 } 2877 } 2878 } 2879 } 2880 } 2881 2882 virtual ~StmtPrinterHelper() {} 2883 2884 const LangOptions &getLangOpts() const { return LangOpts; } 2885 void setBlockID(signed i) { currentBlock = i; } 2886 void setStmtID(unsigned i) { currentStmt = i; } 2887 2888 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2889 StmtMapTy::iterator I = StmtMap.find(S); 2890 2891 if (I == StmtMap.end()) 2892 return false; 2893 2894 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 2895 && I->second.second == currentStmt) { 2896 return false; 2897 } 2898 2899 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2900 return true; 2901 } 2902 2903 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2904 DeclMapTy::iterator I = DeclMap.find(D); 2905 2906 if (I == DeclMap.end()) 2907 return false; 2908 2909 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 2910 && I->second.second == currentStmt) { 2911 return false; 2912 } 2913 2914 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2915 return true; 2916 } 2917}; 2918} // end anonymous namespace 2919 2920 2921namespace { 2922class CFGBlockTerminatorPrint 2923 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2924 2925 llvm::raw_ostream& OS; 2926 StmtPrinterHelper* Helper; 2927 PrintingPolicy Policy; 2928public: 2929 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2930 const PrintingPolicy &Policy) 2931 : OS(os), Helper(helper), Policy(Policy) {} 2932 2933 void VisitIfStmt(IfStmt* I) { 2934 OS << "if "; 2935 I->getCond()->printPretty(OS,Helper,Policy); 2936 } 2937 2938 // Default case. 2939 void VisitStmt(Stmt* Terminator) { 2940 Terminator->printPretty(OS, Helper, Policy); 2941 } 2942 2943 void VisitForStmt(ForStmt* F) { 2944 OS << "for (" ; 2945 if (F->getInit()) 2946 OS << "..."; 2947 OS << "; "; 2948 if (Stmt* C = F->getCond()) 2949 C->printPretty(OS, Helper, Policy); 2950 OS << "; "; 2951 if (F->getInc()) 2952 OS << "..."; 2953 OS << ")"; 2954 } 2955 2956 void VisitWhileStmt(WhileStmt* W) { 2957 OS << "while " ; 2958 if (Stmt* C = W->getCond()) 2959 C->printPretty(OS, Helper, Policy); 2960 } 2961 2962 void VisitDoStmt(DoStmt* D) { 2963 OS << "do ... while "; 2964 if (Stmt* C = D->getCond()) 2965 C->printPretty(OS, Helper, Policy); 2966 } 2967 2968 void VisitSwitchStmt(SwitchStmt* Terminator) { 2969 OS << "switch "; 2970 Terminator->getCond()->printPretty(OS, Helper, Policy); 2971 } 2972 2973 void VisitCXXTryStmt(CXXTryStmt* CS) { 2974 OS << "try ..."; 2975 } 2976 2977 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 2978 C->getCond()->printPretty(OS, Helper, Policy); 2979 OS << " ? ... : ..."; 2980 } 2981 2982 void VisitChooseExpr(ChooseExpr* C) { 2983 OS << "__builtin_choose_expr( "; 2984 C->getCond()->printPretty(OS, Helper, Policy); 2985 OS << " )"; 2986 } 2987 2988 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2989 OS << "goto *"; 2990 I->getTarget()->printPretty(OS, Helper, Policy); 2991 } 2992 2993 void VisitBinaryOperator(BinaryOperator* B) { 2994 if (!B->isLogicalOp()) { 2995 VisitExpr(B); 2996 return; 2997 } 2998 2999 B->getLHS()->printPretty(OS, Helper, Policy); 3000 3001 switch (B->getOpcode()) { 3002 case BO_LOr: 3003 OS << " || ..."; 3004 return; 3005 case BO_LAnd: 3006 OS << " && ..."; 3007 return; 3008 default: 3009 assert(false && "Invalid logical operator."); 3010 } 3011 } 3012 3013 void VisitExpr(Expr* E) { 3014 E->printPretty(OS, Helper, Policy); 3015 } 3016}; 3017} // end anonymous namespace 3018 3019static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3020 const CFGElement &E) { 3021 if (CFGStmt CS = E.getAs<CFGStmt>()) { 3022 Stmt *S = CS; 3023 3024 if (Helper) { 3025 3026 // special printing for statement-expressions. 3027 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3028 CompoundStmt* Sub = SE->getSubStmt(); 3029 3030 if (Sub->children()) { 3031 OS << "({ ... ; "; 3032 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3033 OS << " })\n"; 3034 return; 3035 } 3036 } 3037 // special printing for comma expressions. 3038 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3039 if (B->getOpcode() == BO_Comma) { 3040 OS << "... , "; 3041 Helper->handledStmt(B->getRHS(),OS); 3042 OS << '\n'; 3043 return; 3044 } 3045 } 3046 } 3047 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3048 3049 if (isa<CXXOperatorCallExpr>(S)) { 3050 OS << " (OperatorCall)"; 3051 } else if (isa<CXXBindTemporaryExpr>(S)) { 3052 OS << " (BindTemporary)"; 3053 } 3054 3055 // Expressions need a newline. 3056 if (isa<Expr>(S)) 3057 OS << '\n'; 3058 3059 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 3060 CXXCtorInitializer* I = IE; 3061 if (I->isBaseInitializer()) 3062 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3063 else OS << I->getAnyMember()->getName(); 3064 3065 OS << "("; 3066 if (Expr* IE = I->getInit()) 3067 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3068 OS << ")"; 3069 3070 if (I->isBaseInitializer()) 3071 OS << " (Base initializer)\n"; 3072 else OS << " (Member initializer)\n"; 3073 3074 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 3075 VarDecl* VD = DE.getVarDecl(); 3076 Helper->handleDecl(VD, OS); 3077 3078 const Type* T = VD->getType().getTypePtr(); 3079 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3080 T = RT->getPointeeType().getTypePtr(); 3081 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3082 T = ET; 3083 3084 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3085 OS << " (Implicit destructor)\n"; 3086 3087 } else if (CFGBaseDtor BE = E.getAs<CFGBaseDtor>()) { 3088 const CXXBaseSpecifier *BS = BE.getBaseSpecifier(); 3089 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3090 OS << " (Base object destructor)\n"; 3091 3092 } else if (CFGMemberDtor ME = E.getAs<CFGMemberDtor>()) { 3093 FieldDecl *FD = ME.getFieldDecl(); 3094 3095 const Type *T = FD->getType().getTypePtr(); 3096 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3097 T = ET; 3098 3099 OS << "this->" << FD->getName(); 3100 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3101 OS << " (Member object destructor)\n"; 3102 3103 } else if (CFGTemporaryDtor TE = E.getAs<CFGTemporaryDtor>()) { 3104 CXXBindTemporaryExpr *BT = TE.getBindTemporaryExpr(); 3105 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3106 OS << " (Temporary object destructor)\n"; 3107 } 3108} 3109 3110static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3111 const CFGBlock& B, 3112 StmtPrinterHelper* Helper, bool print_edges) { 3113 3114 if (Helper) Helper->setBlockID(B.getBlockID()); 3115 3116 // Print the header. 3117 OS << "\n [ B" << B.getBlockID(); 3118 3119 if (&B == &cfg->getEntry()) 3120 OS << " (ENTRY) ]\n"; 3121 else if (&B == &cfg->getExit()) 3122 OS << " (EXIT) ]\n"; 3123 else if (&B == cfg->getIndirectGotoBlock()) 3124 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3125 else 3126 OS << " ]\n"; 3127 3128 // Print the label of this block. 3129 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3130 3131 if (print_edges) 3132 OS << " "; 3133 3134 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3135 OS << L->getName(); 3136 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3137 OS << "case "; 3138 C->getLHS()->printPretty(OS, Helper, 3139 PrintingPolicy(Helper->getLangOpts())); 3140 if (C->getRHS()) { 3141 OS << " ... "; 3142 C->getRHS()->printPretty(OS, Helper, 3143 PrintingPolicy(Helper->getLangOpts())); 3144 } 3145 } else if (isa<DefaultStmt>(Label)) 3146 OS << "default"; 3147 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3148 OS << "catch ("; 3149 if (CS->getExceptionDecl()) 3150 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3151 0); 3152 else 3153 OS << "..."; 3154 OS << ")"; 3155 3156 } else 3157 assert(false && "Invalid label statement in CFGBlock."); 3158 3159 OS << ":\n"; 3160 } 3161 3162 // Iterate through the statements in the block and print them. 3163 unsigned j = 1; 3164 3165 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3166 I != E ; ++I, ++j ) { 3167 3168 // Print the statement # in the basic block and the statement itself. 3169 if (print_edges) 3170 OS << " "; 3171 3172 OS << llvm::format("%3d", j) << ": "; 3173 3174 if (Helper) 3175 Helper->setStmtID(j); 3176 3177 print_elem(OS,Helper,*I); 3178 } 3179 3180 // Print the terminator of this block. 3181 if (B.getTerminator()) { 3182 if (print_edges) 3183 OS << " "; 3184 3185 OS << " T: "; 3186 3187 if (Helper) Helper->setBlockID(-1); 3188 3189 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3190 PrintingPolicy(Helper->getLangOpts())); 3191 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3192 OS << '\n'; 3193 } 3194 3195 if (print_edges) { 3196 // Print the predecessors of this block. 3197 OS << " Predecessors (" << B.pred_size() << "):"; 3198 unsigned i = 0; 3199 3200 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3201 I != E; ++I, ++i) { 3202 3203 if (i == 8 || (i-8) == 0) 3204 OS << "\n "; 3205 3206 OS << " B" << (*I)->getBlockID(); 3207 } 3208 3209 OS << '\n'; 3210 3211 // Print the successors of this block. 3212 OS << " Successors (" << B.succ_size() << "):"; 3213 i = 0; 3214 3215 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3216 I != E; ++I, ++i) { 3217 3218 if (i == 8 || (i-8) % 10 == 0) 3219 OS << "\n "; 3220 3221 if (*I) 3222 OS << " B" << (*I)->getBlockID(); 3223 else 3224 OS << " NULL"; 3225 } 3226 3227 OS << '\n'; 3228 } 3229} 3230 3231 3232/// dump - A simple pretty printer of a CFG that outputs to stderr. 3233void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3234 3235/// print - A simple pretty printer of a CFG that outputs to an ostream. 3236void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3237 StmtPrinterHelper Helper(this, LO); 3238 3239 // Print the entry block. 3240 print_block(OS, this, getEntry(), &Helper, true); 3241 3242 // Iterate through the CFGBlocks and print them one by one. 3243 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3244 // Skip the entry block, because we already printed it. 3245 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3246 continue; 3247 3248 print_block(OS, this, **I, &Helper, true); 3249 } 3250 3251 // Print the exit block. 3252 print_block(OS, this, getExit(), &Helper, true); 3253 OS.flush(); 3254} 3255 3256/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3257void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3258 print(llvm::errs(), cfg, LO); 3259} 3260 3261/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3262/// Generally this will only be called from CFG::print. 3263void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3264 const LangOptions &LO) const { 3265 StmtPrinterHelper Helper(cfg, LO); 3266 print_block(OS, cfg, *this, &Helper, true); 3267} 3268 3269/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3270void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3271 const LangOptions &LO) const { 3272 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3273 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3274} 3275 3276Stmt* CFGBlock::getTerminatorCondition() { 3277 Stmt *Terminator = this->Terminator; 3278 if (!Terminator) 3279 return NULL; 3280 3281 Expr* E = NULL; 3282 3283 switch (Terminator->getStmtClass()) { 3284 default: 3285 break; 3286 3287 case Stmt::ForStmtClass: 3288 E = cast<ForStmt>(Terminator)->getCond(); 3289 break; 3290 3291 case Stmt::WhileStmtClass: 3292 E = cast<WhileStmt>(Terminator)->getCond(); 3293 break; 3294 3295 case Stmt::DoStmtClass: 3296 E = cast<DoStmt>(Terminator)->getCond(); 3297 break; 3298 3299 case Stmt::IfStmtClass: 3300 E = cast<IfStmt>(Terminator)->getCond(); 3301 break; 3302 3303 case Stmt::ChooseExprClass: 3304 E = cast<ChooseExpr>(Terminator)->getCond(); 3305 break; 3306 3307 case Stmt::IndirectGotoStmtClass: 3308 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3309 break; 3310 3311 case Stmt::SwitchStmtClass: 3312 E = cast<SwitchStmt>(Terminator)->getCond(); 3313 break; 3314 3315 case Stmt::BinaryConditionalOperatorClass: 3316 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3317 break; 3318 3319 case Stmt::ConditionalOperatorClass: 3320 E = cast<ConditionalOperator>(Terminator)->getCond(); 3321 break; 3322 3323 case Stmt::BinaryOperatorClass: // '&&' and '||' 3324 E = cast<BinaryOperator>(Terminator)->getLHS(); 3325 break; 3326 3327 case Stmt::ObjCForCollectionStmtClass: 3328 return Terminator; 3329 } 3330 3331 return E ? E->IgnoreParens() : NULL; 3332} 3333 3334bool CFGBlock::hasBinaryBranchTerminator() const { 3335 const Stmt *Terminator = this->Terminator; 3336 if (!Terminator) 3337 return false; 3338 3339 Expr* E = NULL; 3340 3341 switch (Terminator->getStmtClass()) { 3342 default: 3343 return false; 3344 3345 case Stmt::ForStmtClass: 3346 case Stmt::WhileStmtClass: 3347 case Stmt::DoStmtClass: 3348 case Stmt::IfStmtClass: 3349 case Stmt::ChooseExprClass: 3350 case Stmt::BinaryConditionalOperatorClass: 3351 case Stmt::ConditionalOperatorClass: 3352 case Stmt::BinaryOperatorClass: 3353 return true; 3354 } 3355 3356 return E ? E->IgnoreParens() : NULL; 3357} 3358 3359 3360//===----------------------------------------------------------------------===// 3361// CFG Graphviz Visualization 3362//===----------------------------------------------------------------------===// 3363 3364 3365#ifndef NDEBUG 3366static StmtPrinterHelper* GraphHelper; 3367#endif 3368 3369void CFG::viewCFG(const LangOptions &LO) const { 3370#ifndef NDEBUG 3371 StmtPrinterHelper H(this, LO); 3372 GraphHelper = &H; 3373 llvm::ViewGraph(this,"CFG"); 3374 GraphHelper = NULL; 3375#endif 3376} 3377 3378namespace llvm { 3379template<> 3380struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3381 3382 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3383 3384 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3385 3386#ifndef NDEBUG 3387 std::string OutSStr; 3388 llvm::raw_string_ostream Out(OutSStr); 3389 print_block(Out,Graph, *Node, GraphHelper, false); 3390 std::string& OutStr = Out.str(); 3391 3392 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3393 3394 // Process string output to make it nicer... 3395 for (unsigned i = 0; i != OutStr.length(); ++i) 3396 if (OutStr[i] == '\n') { // Left justify 3397 OutStr[i] = '\\'; 3398 OutStr.insert(OutStr.begin()+i+1, 'l'); 3399 } 3400 3401 return OutStr; 3402#else 3403 return ""; 3404#endif 3405 } 3406}; 3407} // end namespace llvm 3408