CFG.cpp revision 3179a45a0e91c1dcf3492222170cf4499531bb92
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 "clang/AST/CharUnits.h" 21#include "llvm/Support/GraphWriter.h" 22#include "llvm/Support/Allocator.h" 23#include "llvm/Support/Format.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/OwningPtr.h" 27 28using namespace clang; 29 30namespace { 31 32static SourceLocation GetEndLoc(Decl* D) { 33 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 34 if (Expr* Ex = VD->getInit()) 35 return Ex->getSourceRange().getEnd(); 36 return D->getLocation(); 37} 38 39class CFGBuilder; 40 41/// The CFG builder uses a recursive algorithm to build the CFG. When 42/// we process an expression, sometimes we know that we must add the 43/// subexpressions as block-level expressions. For example: 44/// 45/// exp1 || exp2 46/// 47/// When processing the '||' expression, we know that exp1 and exp2 48/// need to be added as block-level expressions, even though they 49/// might not normally need to be. AddStmtChoice records this 50/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 51/// the builder has an option not to add a subexpression as a 52/// block-level expression. 53/// 54class AddStmtChoice { 55public: 56 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 57 58 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 59 60 bool alwaysAdd(CFGBuilder &builder, 61 const Stmt *stmt) const; 62 63 /// Return a copy of this object, except with the 'always-add' bit 64 /// set as specified. 65 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 66 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 67 } 68 69private: 70 Kind kind; 71}; 72 73/// LocalScope - Node in tree of local scopes created for C++ implicit 74/// destructor calls generation. It contains list of automatic variables 75/// declared in the scope and link to position in previous scope this scope 76/// began in. 77/// 78/// The process of creating local scopes is as follows: 79/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 80/// - Before processing statements in scope (e.g. CompoundStmt) create 81/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 82/// and set CFGBuilder::ScopePos to the end of new scope, 83/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 84/// at this VarDecl, 85/// - For every normal (without jump) end of scope add to CFGBlock destructors 86/// for objects in the current scope, 87/// - For every jump add to CFGBlock destructors for objects 88/// between CFGBuilder::ScopePos and local scope position saved for jump 89/// target. Thanks to C++ restrictions on goto jumps we can be sure that 90/// jump target position will be on the path to root from CFGBuilder::ScopePos 91/// (adding any variable that doesn't need constructor to be called to 92/// LocalScope can break this assumption), 93/// 94class LocalScope { 95public: 96 typedef BumpVector<VarDecl*> AutomaticVarsTy; 97 98 /// const_iterator - Iterates local scope backwards and jumps to previous 99 /// scope on reaching the beginning of currently iterated scope. 100 class const_iterator { 101 const LocalScope* Scope; 102 103 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 104 /// Invalid iterator (with null Scope) has VarIter equal to 0. 105 unsigned VarIter; 106 107 public: 108 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 109 /// Incrementing invalid iterator is allowed and will result in invalid 110 /// iterator. 111 const_iterator() 112 : Scope(NULL), VarIter(0) {} 113 114 /// Create valid iterator. In case when S.Prev is an invalid iterator and 115 /// I is equal to 0, this will create invalid iterator. 116 const_iterator(const LocalScope& S, unsigned I) 117 : Scope(&S), VarIter(I) { 118 // Iterator to "end" of scope is not allowed. Handle it by going up 119 // in scopes tree possibly up to invalid iterator in the root. 120 if (VarIter == 0 && Scope) 121 *this = Scope->Prev; 122 } 123 124 VarDecl* const* operator->() const { 125 assert (Scope && "Dereferencing invalid iterator is not allowed"); 126 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 127 return &Scope->Vars[VarIter - 1]; 128 } 129 VarDecl* operator*() const { 130 return *this->operator->(); 131 } 132 133 const_iterator& operator++() { 134 if (!Scope) 135 return *this; 136 137 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 138 --VarIter; 139 if (VarIter == 0) 140 *this = Scope->Prev; 141 return *this; 142 } 143 const_iterator operator++(int) { 144 const_iterator P = *this; 145 ++*this; 146 return P; 147 } 148 149 bool operator==(const const_iterator& rhs) const { 150 return Scope == rhs.Scope && VarIter == rhs.VarIter; 151 } 152 bool operator!=(const const_iterator& rhs) const { 153 return !(*this == rhs); 154 } 155 156 operator bool() const { 157 return *this != const_iterator(); 158 } 159 160 int distance(const_iterator L); 161 }; 162 163 friend class const_iterator; 164 165private: 166 BumpVectorContext ctx; 167 168 /// Automatic variables in order of declaration. 169 AutomaticVarsTy Vars; 170 /// Iterator to variable in previous scope that was declared just before 171 /// begin of this scope. 172 const_iterator Prev; 173 174public: 175 /// Constructs empty scope linked to previous scope in specified place. 176 LocalScope(BumpVectorContext &ctx, const_iterator P) 177 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 178 179 /// Begin of scope in direction of CFG building (backwards). 180 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 181 182 void addVar(VarDecl* VD) { 183 Vars.push_back(VD, ctx); 184 } 185}; 186 187/// distance - Calculates distance from this to L. L must be reachable from this 188/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 189/// number of scopes between this and L. 190int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 191 int D = 0; 192 const_iterator F = *this; 193 while (F.Scope != L.Scope) { 194 assert (F != const_iterator() 195 && "L iterator is not reachable from F iterator."); 196 D += F.VarIter; 197 F = F.Scope->Prev; 198 } 199 D += F.VarIter - L.VarIter; 200 return D; 201} 202 203/// BlockScopePosPair - Structure for specifying position in CFG during its 204/// build process. It consists of CFGBlock that specifies position in CFG graph 205/// and LocalScope::const_iterator that specifies position in LocalScope graph. 206struct BlockScopePosPair { 207 BlockScopePosPair() : block(0) {} 208 BlockScopePosPair(CFGBlock* b, LocalScope::const_iterator scopePos) 209 : block(b), scopePosition(scopePos) {} 210 211 CFGBlock *block; 212 LocalScope::const_iterator scopePosition; 213}; 214 215/// TryResult - a class representing a variant over the values 216/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 217/// and is used by the CFGBuilder to decide if a branch condition 218/// can be decided up front during CFG construction. 219class TryResult { 220 int X; 221public: 222 TryResult(bool b) : X(b ? 1 : 0) {} 223 TryResult() : X(-1) {} 224 225 bool isTrue() const { return X == 1; } 226 bool isFalse() const { return X == 0; } 227 bool isKnown() const { return X >= 0; } 228 void negate() { 229 assert(isKnown()); 230 X ^= 0x1; 231 } 232}; 233 234/// CFGBuilder - This class implements CFG construction from an AST. 235/// The builder is stateful: an instance of the builder should be used to only 236/// construct a single CFG. 237/// 238/// Example usage: 239/// 240/// CFGBuilder builder; 241/// CFG* cfg = builder.BuildAST(stmt1); 242/// 243/// CFG construction is done via a recursive walk of an AST. We actually parse 244/// the AST in reverse order so that the successor of a basic block is 245/// constructed prior to its predecessor. This allows us to nicely capture 246/// implicit fall-throughs without extra basic blocks. 247/// 248class CFGBuilder { 249 typedef BlockScopePosPair JumpTarget; 250 typedef BlockScopePosPair JumpSource; 251 252 ASTContext *Context; 253 llvm::OwningPtr<CFG> cfg; 254 255 CFGBlock* Block; 256 CFGBlock* Succ; 257 JumpTarget ContinueJumpTarget; 258 JumpTarget BreakJumpTarget; 259 CFGBlock* SwitchTerminatedBlock; 260 CFGBlock* DefaultCaseBlock; 261 CFGBlock* TryTerminatedBlock; 262 263 // Current position in local scope. 264 LocalScope::const_iterator ScopePos; 265 266 // LabelMap records the mapping from Label expressions to their jump targets. 267 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 268 LabelMapTy LabelMap; 269 270 // A list of blocks that end with a "goto" that must be backpatched to their 271 // resolved targets upon completion of CFG construction. 272 typedef std::vector<JumpSource> BackpatchBlocksTy; 273 BackpatchBlocksTy BackpatchBlocks; 274 275 // A list of labels whose address has been taken (for indirect gotos). 276 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 277 LabelSetTy AddressTakenLabels; 278 279 bool badCFG; 280 const CFG::BuildOptions &BuildOpts; 281 282 // State to track for building switch statements. 283 bool switchExclusivelyCovered; 284 Expr::EvalResult *switchCond; 285 286public: 287 explicit CFGBuilder(ASTContext *astContext, 288 const CFG::BuildOptions &buildOpts) 289 : Context(astContext), cfg(new CFG()), // crew a new CFG 290 Block(NULL), Succ(NULL), 291 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 292 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 293 switchExclusivelyCovered(false), switchCond(0) {} 294 295 // buildCFG - Used by external clients to construct the CFG. 296 CFG* buildCFG(const Decl *D, Stmt *Statement); 297 298private: 299 // Visitors to walk an AST and construct the CFG. 300 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 301 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 302 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 303 CFGBlock *VisitBreakStmt(BreakStmt *B); 304 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 305 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 306 AddStmtChoice asc); 307 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 308 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 309 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 310 AddStmtChoice asc); 311 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 312 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 313 AddStmtChoice asc); 314 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 315 AddStmtChoice asc); 316 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 317 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 318 CFGBlock *VisitCaseStmt(CaseStmt *C); 319 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 320 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 321 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 322 AddStmtChoice asc); 323 CFGBlock *VisitContinueStmt(ContinueStmt *C); 324 CFGBlock *VisitDeclStmt(DeclStmt *DS); 325 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 326 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 327 CFGBlock *VisitDoStmt(DoStmt *D); 328 CFGBlock *VisitForStmt(ForStmt *F); 329 CFGBlock *VisitGotoStmt(GotoStmt* G); 330 CFGBlock *VisitIfStmt(IfStmt *I); 331 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 332 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 333 CFGBlock *VisitLabelStmt(LabelStmt *L); 334 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 335 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 336 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 337 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 338 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 339 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 340 CFGBlock *VisitReturnStmt(ReturnStmt* R); 341 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 342 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 343 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 344 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 345 CFGBlock *VisitWhileStmt(WhileStmt *W); 346 347 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 348 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 349 CFGBlock *VisitChildren(Stmt* S); 350 351 // Visitors to walk an AST and generate destructors of temporaries in 352 // full expression. 353 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 354 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 355 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 356 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 357 bool BindToTemporary); 358 CFGBlock * 359 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 360 bool BindToTemporary); 361 362 // NYS == Not Yet Supported 363 CFGBlock* NYS() { 364 badCFG = true; 365 return Block; 366 } 367 368 void autoCreateBlock() { if (!Block) Block = createBlock(); } 369 CFGBlock *createBlock(bool add_successor = true); 370 371 CFGBlock *addStmt(Stmt *S) { 372 return Visit(S, AddStmtChoice::AlwaysAdd); 373 } 374 CFGBlock *addInitializer(CXXCtorInitializer *I); 375 void addAutomaticObjDtors(LocalScope::const_iterator B, 376 LocalScope::const_iterator E, Stmt* S); 377 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 378 379 // Local scopes creation. 380 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 381 382 void addLocalScopeForStmt(Stmt* S); 383 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 384 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 385 386 void addLocalScopeAndDtors(Stmt* S); 387 388 // Interface to CFGBlock - adding CFGElements. 389 void appendStmt(CFGBlock *B, Stmt *S) { 390 B->appendStmt(S, cfg->getBumpVectorContext()); 391 } 392 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 393 B->appendInitializer(I, cfg->getBumpVectorContext()); 394 } 395 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 396 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 397 } 398 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 399 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 400 } 401 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 402 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 403 } 404 405 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 406 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 407 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 408 LocalScope::const_iterator E, Stmt* S); 409 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 410 LocalScope::const_iterator B, LocalScope::const_iterator E); 411 412 void addSuccessor(CFGBlock *B, CFGBlock *S) { 413 B->addSuccessor(S, cfg->getBumpVectorContext()); 414 } 415 416 /// Try and evaluate an expression to an integer constant. 417 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 418 if (!BuildOpts.PruneTriviallyFalseEdges) 419 return false; 420 return !S->isTypeDependent() && 421 !S->isValueDependent() && 422 S->Evaluate(outResult, *Context); 423 } 424 425 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 426 /// if we can evaluate to a known value, otherwise return -1. 427 TryResult tryEvaluateBool(Expr *S) { 428 Expr::EvalResult Result; 429 if (!tryEvaluate(S, Result)) 430 return TryResult(); 431 432 if (Result.Val.isInt()) 433 return Result.Val.getInt().getBoolValue(); 434 435 if (Result.Val.isLValue()) { 436 Expr *e = Result.Val.getLValueBase(); 437 const CharUnits &c = Result.Val.getLValueOffset(); 438 if (!e && c.isZero()) 439 return false; 440 } 441 return TryResult(); 442 } 443 444}; 445 446bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 447 const Stmt *stmt) const { 448 return kind == AlwaysAdd; 449} 450 451// FIXME: Add support for dependent-sized array types in C++? 452// Does it even make sense to build a CFG for an uninstantiated template? 453static const VariableArrayType *FindVA(const Type *t) { 454 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 455 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 456 if (vat->getSizeExpr()) 457 return vat; 458 459 t = vt->getElementType().getTypePtr(); 460 } 461 462 return 0; 463} 464 465/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 466/// arbitrary statement. Examples include a single expression or a function 467/// body (compound statement). The ownership of the returned CFG is 468/// transferred to the caller. If CFG construction fails, this method returns 469/// NULL. 470CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement) { 471 assert(cfg.get()); 472 if (!Statement) 473 return NULL; 474 475 // Create an empty block that will serve as the exit block for the CFG. Since 476 // this is the first block added to the CFG, it will be implicitly registered 477 // as the exit block. 478 Succ = createBlock(); 479 assert(Succ == &cfg->getExit()); 480 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 481 482 if (BuildOpts.AddImplicitDtors) 483 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 484 addImplicitDtorsForDestructor(DD); 485 486 // Visit the statements and create the CFG. 487 CFGBlock *B = addStmt(Statement); 488 489 if (badCFG) 490 return NULL; 491 492 // For C++ constructor add initializers to CFG. 493 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 494 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 495 E = CD->init_rend(); I != E; ++I) { 496 B = addInitializer(*I); 497 if (badCFG) 498 return NULL; 499 } 500 } 501 502 if (B) 503 Succ = B; 504 505 // Backpatch the gotos whose label -> block mappings we didn't know when we 506 // encountered them. 507 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 508 E = BackpatchBlocks.end(); I != E; ++I ) { 509 510 CFGBlock* B = I->block; 511 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 512 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 513 514 // If there is no target for the goto, then we are looking at an 515 // incomplete AST. Handle this by not registering a successor. 516 if (LI == LabelMap.end()) continue; 517 518 JumpTarget JT = LI->second; 519 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 520 JT.scopePosition); 521 addSuccessor(B, JT.block); 522 } 523 524 // Add successors to the Indirect Goto Dispatch block (if we have one). 525 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 526 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 527 E = AddressTakenLabels.end(); I != E; ++I ) { 528 529 // Lookup the target block. 530 LabelMapTy::iterator LI = LabelMap.find(*I); 531 532 // If there is no target block that contains label, then we are looking 533 // at an incomplete AST. Handle this by not registering a successor. 534 if (LI == LabelMap.end()) continue; 535 536 addSuccessor(B, LI->second.block); 537 } 538 539 // Create an empty entry block that has no predecessors. 540 cfg->setEntry(createBlock()); 541 542 return cfg.take(); 543} 544 545/// createBlock - Used to lazily create blocks that are connected 546/// to the current (global) succcessor. 547CFGBlock* CFGBuilder::createBlock(bool add_successor) { 548 CFGBlock* B = cfg->createBlock(); 549 if (add_successor && Succ) 550 addSuccessor(B, Succ); 551 return B; 552} 553 554/// addInitializer - Add C++ base or member initializer element to CFG. 555CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 556 if (!BuildOpts.AddInitializers) 557 return Block; 558 559 bool IsReference = false; 560 bool HasTemporaries = false; 561 562 // Destructors of temporaries in initialization expression should be called 563 // after initialization finishes. 564 Expr *Init = I->getInit(); 565 if (Init) { 566 if (FieldDecl *FD = I->getAnyMember()) 567 IsReference = FD->getType()->isReferenceType(); 568 HasTemporaries = isa<ExprWithCleanups>(Init); 569 570 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 571 // Generate destructors for temporaries in initialization expression. 572 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 573 IsReference); 574 } 575 } 576 577 autoCreateBlock(); 578 appendInitializer(Block, I); 579 580 if (Init) { 581 if (HasTemporaries) { 582 // For expression with temporaries go directly to subexpression to omit 583 // generating destructors for the second time. 584 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 585 } 586 return Visit(Init); 587 } 588 589 return Block; 590} 591 592/// addAutomaticObjDtors - Add to current block automatic objects destructors 593/// for objects in range of local scope positions. Use S as trigger statement 594/// for destructors. 595void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 596 LocalScope::const_iterator E, Stmt* S) { 597 if (!BuildOpts.AddImplicitDtors) 598 return; 599 600 if (B == E) 601 return; 602 603 autoCreateBlock(); 604 appendAutomaticObjDtors(Block, B, E, S); 605} 606 607/// addImplicitDtorsForDestructor - Add implicit destructors generated for 608/// base and member objects in destructor. 609void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 610 assert (BuildOpts.AddImplicitDtors 611 && "Can be called only when dtors should be added"); 612 const CXXRecordDecl *RD = DD->getParent(); 613 614 // At the end destroy virtual base objects. 615 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 616 VE = RD->vbases_end(); VI != VE; ++VI) { 617 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 618 if (!CD->hasTrivialDestructor()) { 619 autoCreateBlock(); 620 appendBaseDtor(Block, VI); 621 } 622 } 623 624 // Before virtual bases destroy direct base objects. 625 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 626 BE = RD->bases_end(); BI != BE; ++BI) { 627 if (!BI->isVirtual()) { 628 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 629 if (!CD->hasTrivialDestructor()) { 630 autoCreateBlock(); 631 appendBaseDtor(Block, BI); 632 } 633 } 634 } 635 636 // First destroy member objects. 637 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 638 FE = RD->field_end(); FI != FE; ++FI) { 639 // Check for constant size array. Set type to array element type. 640 QualType QT = FI->getType(); 641 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 642 if (AT->getSize() == 0) 643 continue; 644 QT = AT->getElementType(); 645 } 646 647 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 648 if (!CD->hasTrivialDestructor()) { 649 autoCreateBlock(); 650 appendMemberDtor(Block, *FI); 651 } 652 } 653} 654 655/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 656/// way return valid LocalScope object. 657LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 658 if (!Scope) { 659 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 660 Scope = alloc.Allocate<LocalScope>(); 661 BumpVectorContext ctx(alloc); 662 new (Scope) LocalScope(ctx, ScopePos); 663 } 664 return Scope; 665} 666 667/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 668/// that should create implicit scope (e.g. if/else substatements). 669void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 670 if (!BuildOpts.AddImplicitDtors) 671 return; 672 673 LocalScope *Scope = 0; 674 675 // For compound statement we will be creating explicit scope. 676 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 677 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 678 ; BI != BE; ++BI) { 679 Stmt *SI = *BI; 680 if (LabelStmt *LS = dyn_cast<LabelStmt>(SI)) 681 SI = LS->getSubStmt(); 682 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 683 Scope = addLocalScopeForDeclStmt(DS, Scope); 684 } 685 return; 686 } 687 688 // For any other statement scope will be implicit and as such will be 689 // interesting only for DeclStmt. 690 if (LabelStmt *LS = dyn_cast<LabelStmt>(S)) 691 S = LS->getSubStmt(); 692 if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) 693 addLocalScopeForDeclStmt(DS); 694} 695 696/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 697/// reuse Scope if not NULL. 698LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 699 LocalScope* Scope) { 700 if (!BuildOpts.AddImplicitDtors) 701 return Scope; 702 703 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 704 ; DI != DE; ++DI) { 705 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 706 Scope = addLocalScopeForVarDecl(VD, Scope); 707 } 708 return Scope; 709} 710 711/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 712/// create add scope for automatic objects and temporary objects bound to 713/// const reference. Will reuse Scope if not NULL. 714LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 715 LocalScope* Scope) { 716 if (!BuildOpts.AddImplicitDtors) 717 return Scope; 718 719 // Check if variable is local. 720 switch (VD->getStorageClass()) { 721 case SC_None: 722 case SC_Auto: 723 case SC_Register: 724 break; 725 default: return Scope; 726 } 727 728 // Check for const references bound to temporary. Set type to pointee. 729 QualType QT = VD->getType(); 730 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 731 QT = RT->getPointeeType(); 732 if (!QT.isConstQualified()) 733 return Scope; 734 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 735 return Scope; 736 } 737 738 // Check for constant size array. Set type to array element type. 739 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 740 if (AT->getSize() == 0) 741 return Scope; 742 QT = AT->getElementType(); 743 } 744 745 // Check if type is a C++ class with non-trivial destructor. 746 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 747 if (!CD->hasTrivialDestructor()) { 748 // Add the variable to scope 749 Scope = createOrReuseLocalScope(Scope); 750 Scope->addVar(VD); 751 ScopePos = Scope->begin(); 752 } 753 return Scope; 754} 755 756/// addLocalScopeAndDtors - For given statement add local scope for it and 757/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 758void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 759 if (!BuildOpts.AddImplicitDtors) 760 return; 761 762 LocalScope::const_iterator scopeBeginPos = ScopePos; 763 addLocalScopeForStmt(S); 764 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 765} 766 767/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 768/// automatic storage duration to CFGBlock's elements vector. Insertion will be 769/// performed in place specified with iterator. 770void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 771 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 772 BumpVectorContext& C = cfg->getBumpVectorContext(); 773 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 774 while (B != E) 775 I = Blk->insertAutomaticObjDtor(I, *B++, S); 776} 777 778/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 779/// automatic storage duration to CFGBlock's elements vector. Elements will be 780/// appended to physical end of the vector which happens to be logical 781/// beginning. 782void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 783 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 784 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 785} 786 787/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 788/// variables with automatic storage duration to CFGBlock's elements vector. 789/// Elements will be prepended to physical beginning of the vector which 790/// happens to be logical end. Use blocks terminator as statement that specifies 791/// destructors call site. 792void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 793 LocalScope::const_iterator B, LocalScope::const_iterator E) { 794 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 795} 796 797/// Visit - Walk the subtree of a statement and add extra 798/// blocks for ternary operators, &&, and ||. We also process "," and 799/// DeclStmts (which may contain nested control-flow). 800CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 801tryAgain: 802 if (!S) { 803 badCFG = true; 804 return 0; 805 } 806 switch (S->getStmtClass()) { 807 default: 808 return VisitStmt(S, asc); 809 810 case Stmt::AddrLabelExprClass: 811 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 812 813 case Stmt::BinaryConditionalOperatorClass: 814 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 815 816 case Stmt::BinaryOperatorClass: 817 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 818 819 case Stmt::BlockExprClass: 820 return VisitBlockExpr(cast<BlockExpr>(S), asc); 821 822 case Stmt::BreakStmtClass: 823 return VisitBreakStmt(cast<BreakStmt>(S)); 824 825 case Stmt::CallExprClass: 826 case Stmt::CXXOperatorCallExprClass: 827 return VisitCallExpr(cast<CallExpr>(S), asc); 828 829 case Stmt::CaseStmtClass: 830 return VisitCaseStmt(cast<CaseStmt>(S)); 831 832 case Stmt::ChooseExprClass: 833 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 834 835 case Stmt::CompoundStmtClass: 836 return VisitCompoundStmt(cast<CompoundStmt>(S)); 837 838 case Stmt::ConditionalOperatorClass: 839 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 840 841 case Stmt::ContinueStmtClass: 842 return VisitContinueStmt(cast<ContinueStmt>(S)); 843 844 case Stmt::CXXCatchStmtClass: 845 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 846 847 case Stmt::ExprWithCleanupsClass: 848 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 849 850 case Stmt::CXXBindTemporaryExprClass: 851 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 852 853 case Stmt::CXXConstructExprClass: 854 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 855 856 case Stmt::CXXFunctionalCastExprClass: 857 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 858 859 case Stmt::CXXTemporaryObjectExprClass: 860 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 861 862 case Stmt::CXXMemberCallExprClass: 863 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 864 865 case Stmt::CXXThrowExprClass: 866 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 867 868 case Stmt::CXXTryStmtClass: 869 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 870 871 case Stmt::DeclStmtClass: 872 return VisitDeclStmt(cast<DeclStmt>(S)); 873 874 case Stmt::DefaultStmtClass: 875 return VisitDefaultStmt(cast<DefaultStmt>(S)); 876 877 case Stmt::DoStmtClass: 878 return VisitDoStmt(cast<DoStmt>(S)); 879 880 case Stmt::ForStmtClass: 881 return VisitForStmt(cast<ForStmt>(S)); 882 883 case Stmt::GotoStmtClass: 884 return VisitGotoStmt(cast<GotoStmt>(S)); 885 886 case Stmt::IfStmtClass: 887 return VisitIfStmt(cast<IfStmt>(S)); 888 889 case Stmt::ImplicitCastExprClass: 890 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 891 892 case Stmt::IndirectGotoStmtClass: 893 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 894 895 case Stmt::LabelStmtClass: 896 return VisitLabelStmt(cast<LabelStmt>(S)); 897 898 case Stmt::MemberExprClass: 899 return VisitMemberExpr(cast<MemberExpr>(S), asc); 900 901 case Stmt::ObjCAtCatchStmtClass: 902 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 903 904 case Stmt::ObjCAtSynchronizedStmtClass: 905 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 906 907 case Stmt::ObjCAtThrowStmtClass: 908 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 909 910 case Stmt::ObjCAtTryStmtClass: 911 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 912 913 case Stmt::ObjCForCollectionStmtClass: 914 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 915 916 case Stmt::ParenExprClass: 917 S = cast<ParenExpr>(S)->getSubExpr(); 918 goto tryAgain; 919 920 case Stmt::NullStmtClass: 921 return Block; 922 923 case Stmt::ReturnStmtClass: 924 return VisitReturnStmt(cast<ReturnStmt>(S)); 925 926 case Stmt::SizeOfAlignOfExprClass: 927 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 928 929 case Stmt::StmtExprClass: 930 return VisitStmtExpr(cast<StmtExpr>(S), asc); 931 932 case Stmt::SwitchStmtClass: 933 return VisitSwitchStmt(cast<SwitchStmt>(S)); 934 935 case Stmt::UnaryOperatorClass: 936 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 937 938 case Stmt::WhileStmtClass: 939 return VisitWhileStmt(cast<WhileStmt>(S)); 940 } 941} 942 943CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 944 if (asc.alwaysAdd(*this, S)) { 945 autoCreateBlock(); 946 appendStmt(Block, S); 947 } 948 949 return VisitChildren(S); 950} 951 952/// VisitChildren - Visit the children of a Stmt. 953CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 954 CFGBlock *lastBlock = Block; 955 for (Stmt::child_range I = Terminator->children(); I; ++I) 956 if (Stmt *child = *I) 957 if (CFGBlock *b = Visit(child)) 958 lastBlock = b; 959 960 return lastBlock; 961} 962 963CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 964 AddStmtChoice asc) { 965 AddressTakenLabels.insert(A->getLabel()); 966 967 if (asc.alwaysAdd(*this, A)) { 968 autoCreateBlock(); 969 appendStmt(Block, A); 970 } 971 972 return Block; 973} 974 975CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 976 AddStmtChoice asc) { 977 if (asc.alwaysAdd(*this, U)) { 978 autoCreateBlock(); 979 appendStmt(Block, U); 980 } 981 982 return Visit(U->getSubExpr(), AddStmtChoice()); 983} 984 985CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 986 AddStmtChoice asc) { 987 if (B->isLogicalOp()) { // && or || 988 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 989 appendStmt(ConfluenceBlock, B); 990 991 if (badCFG) 992 return 0; 993 994 // create the block evaluating the LHS 995 CFGBlock* LHSBlock = createBlock(false); 996 LHSBlock->setTerminator(B); 997 998 // create the block evaluating the RHS 999 Succ = ConfluenceBlock; 1000 Block = NULL; 1001 CFGBlock* RHSBlock = addStmt(B->getRHS()); 1002 1003 if (RHSBlock) { 1004 if (badCFG) 1005 return 0; 1006 } else { 1007 // Create an empty block for cases where the RHS doesn't require 1008 // any explicit statements in the CFG. 1009 RHSBlock = createBlock(); 1010 } 1011 1012 // See if this is a known constant. 1013 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1014 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1015 KnownVal.negate(); 1016 1017 // Now link the LHSBlock with RHSBlock. 1018 if (B->getOpcode() == BO_LOr) { 1019 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1020 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1021 } else { 1022 assert(B->getOpcode() == BO_LAnd); 1023 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1024 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1025 } 1026 1027 // Generate the blocks for evaluating the LHS. 1028 Block = LHSBlock; 1029 return addStmt(B->getLHS()); 1030 } 1031 1032 if (B->getOpcode() == BO_Comma) { // , 1033 autoCreateBlock(); 1034 appendStmt(Block, B); 1035 addStmt(B->getRHS()); 1036 return addStmt(B->getLHS()); 1037 } 1038 1039 if (B->isAssignmentOp()) { 1040 if (asc.alwaysAdd(*this, B)) { 1041 autoCreateBlock(); 1042 appendStmt(Block, B); 1043 } 1044 Visit(B->getLHS()); 1045 return Visit(B->getRHS()); 1046 } 1047 1048 if (asc.alwaysAdd(*this, B)) { 1049 autoCreateBlock(); 1050 appendStmt(Block, B); 1051 } 1052 1053 CFGBlock *RBlock = Visit(B->getRHS()); 1054 CFGBlock *LBlock = Visit(B->getLHS()); 1055 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1056 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1057 // return RBlock. Otherwise we'll incorrectly return NULL. 1058 return (LBlock ? LBlock : RBlock); 1059} 1060 1061CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1062 if (asc.alwaysAdd(*this, E)) { 1063 autoCreateBlock(); 1064 appendStmt(Block, E); 1065 } 1066 return Block; 1067} 1068 1069CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1070 // "break" is a control-flow statement. Thus we stop processing the current 1071 // block. 1072 if (badCFG) 1073 return 0; 1074 1075 // Now create a new block that ends with the break statement. 1076 Block = createBlock(false); 1077 Block->setTerminator(B); 1078 1079 // If there is no target for the break, then we are looking at an incomplete 1080 // AST. This means that the CFG cannot be constructed. 1081 if (BreakJumpTarget.block) { 1082 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1083 addSuccessor(Block, BreakJumpTarget.block); 1084 } else 1085 badCFG = true; 1086 1087 1088 return Block; 1089} 1090 1091static bool CanThrow(Expr *E) { 1092 QualType Ty = E->getType(); 1093 if (Ty->isFunctionPointerType()) 1094 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1095 else if (Ty->isBlockPointerType()) 1096 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1097 1098 const FunctionType *FT = Ty->getAs<FunctionType>(); 1099 if (FT) { 1100 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1101 if (Proto->hasEmptyExceptionSpec()) 1102 return false; 1103 } 1104 return true; 1105} 1106 1107CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1108 // If this is a call to a no-return function, this stops the block here. 1109 bool NoReturn = false; 1110 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 1111 NoReturn = true; 1112 } 1113 1114 bool AddEHEdge = false; 1115 1116 // Languages without exceptions are assumed to not throw. 1117 if (Context->getLangOptions().Exceptions) { 1118 if (BuildOpts.AddEHEdges) 1119 AddEHEdge = true; 1120 } 1121 1122 if (FunctionDecl *FD = C->getDirectCallee()) { 1123 if (FD->hasAttr<NoReturnAttr>()) 1124 NoReturn = true; 1125 if (FD->hasAttr<NoThrowAttr>()) 1126 AddEHEdge = false; 1127 } 1128 1129 if (!CanThrow(C->getCallee())) 1130 AddEHEdge = false; 1131 1132 if (!NoReturn && !AddEHEdge) 1133 return VisitStmt(C, asc.withAlwaysAdd(true)); 1134 1135 if (Block) { 1136 Succ = Block; 1137 if (badCFG) 1138 return 0; 1139 } 1140 1141 Block = createBlock(!NoReturn); 1142 appendStmt(Block, C); 1143 1144 if (NoReturn) { 1145 // Wire this to the exit block directly. 1146 addSuccessor(Block, &cfg->getExit()); 1147 } 1148 if (AddEHEdge) { 1149 // Add exceptional edges. 1150 if (TryTerminatedBlock) 1151 addSuccessor(Block, TryTerminatedBlock); 1152 else 1153 addSuccessor(Block, &cfg->getExit()); 1154 } 1155 1156 return VisitChildren(C); 1157} 1158 1159CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1160 AddStmtChoice asc) { 1161 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1162 appendStmt(ConfluenceBlock, C); 1163 if (badCFG) 1164 return 0; 1165 1166 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1167 Succ = ConfluenceBlock; 1168 Block = NULL; 1169 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1170 if (badCFG) 1171 return 0; 1172 1173 Succ = ConfluenceBlock; 1174 Block = NULL; 1175 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1176 if (badCFG) 1177 return 0; 1178 1179 Block = createBlock(false); 1180 // See if this is a known constant. 1181 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1182 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1183 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1184 Block->setTerminator(C); 1185 return addStmt(C->getCond()); 1186} 1187 1188 1189CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1190 addLocalScopeAndDtors(C); 1191 CFGBlock* LastBlock = Block; 1192 1193 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1194 I != E; ++I ) { 1195 // If we hit a segment of code just containing ';' (NullStmts), we can 1196 // get a null block back. In such cases, just use the LastBlock 1197 if (CFGBlock *newBlock = addStmt(*I)) 1198 LastBlock = newBlock; 1199 1200 if (badCFG) 1201 return NULL; 1202 } 1203 1204 return LastBlock; 1205} 1206 1207CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1208 AddStmtChoice asc) { 1209 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1210 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1211 1212 // Create the confluence block that will "merge" the results of the ternary 1213 // expression. 1214 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1215 appendStmt(ConfluenceBlock, C); 1216 if (badCFG) 1217 return 0; 1218 1219 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1220 1221 // Create a block for the LHS expression if there is an LHS expression. A 1222 // GCC extension allows LHS to be NULL, causing the condition to be the 1223 // value that is returned instead. 1224 // e.g: x ?: y is shorthand for: x ? x : y; 1225 Succ = ConfluenceBlock; 1226 Block = NULL; 1227 CFGBlock* LHSBlock = 0; 1228 const Expr *trueExpr = C->getTrueExpr(); 1229 if (trueExpr != opaqueValue) { 1230 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1231 if (badCFG) 1232 return 0; 1233 Block = NULL; 1234 } 1235 else 1236 LHSBlock = ConfluenceBlock; 1237 1238 // Create the block for the RHS expression. 1239 Succ = ConfluenceBlock; 1240 CFGBlock* RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1241 if (badCFG) 1242 return 0; 1243 1244 // Create the block that will contain the condition. 1245 Block = createBlock(false); 1246 1247 // See if this is a known constant. 1248 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1249 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1250 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1251 Block->setTerminator(C); 1252 Expr *condExpr = C->getCond(); 1253 1254 if (opaqueValue) { 1255 // Run the condition expression if it's not trivially expressed in 1256 // terms of the opaque value (or if there is no opaque value). 1257 if (condExpr != opaqueValue) 1258 addStmt(condExpr); 1259 1260 // Before that, run the common subexpression if there was one. 1261 // At least one of this or the above will be run. 1262 return addStmt(BCO->getCommon()); 1263 } 1264 1265 return addStmt(condExpr); 1266} 1267 1268CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1269 if (DS->isSingleDecl()) 1270 return VisitDeclSubExpr(DS); 1271 1272 CFGBlock *B = 0; 1273 1274 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1275 typedef llvm::SmallVector<Decl*,10> BufTy; 1276 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1277 1278 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1279 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1280 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1281 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1282 1283 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1284 // automatically freed with the CFG. 1285 DeclGroupRef DG(*I); 1286 Decl *D = *I; 1287 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1288 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1289 1290 // Append the fake DeclStmt to block. 1291 B = VisitDeclSubExpr(DSNew); 1292 } 1293 1294 return B; 1295} 1296 1297/// VisitDeclSubExpr - Utility method to add block-level expressions for 1298/// DeclStmts and initializers in them. 1299CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1300 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1301 1302 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1303 1304 if (!VD) { 1305 autoCreateBlock(); 1306 appendStmt(Block, DS); 1307 return Block; 1308 } 1309 1310 bool IsReference = false; 1311 bool HasTemporaries = false; 1312 1313 // Destructors of temporaries in initialization expression should be called 1314 // after initialization finishes. 1315 Expr *Init = VD->getInit(); 1316 if (Init) { 1317 IsReference = VD->getType()->isReferenceType(); 1318 HasTemporaries = isa<ExprWithCleanups>(Init); 1319 1320 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1321 // Generate destructors for temporaries in initialization expression. 1322 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1323 IsReference); 1324 } 1325 } 1326 1327 autoCreateBlock(); 1328 appendStmt(Block, DS); 1329 1330 if (Init) { 1331 if (HasTemporaries) 1332 // For expression with temporaries go directly to subexpression to omit 1333 // generating destructors for the second time. 1334 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1335 else 1336 Visit(Init); 1337 } 1338 1339 // If the type of VD is a VLA, then we must process its size expressions. 1340 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1341 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1342 Block = addStmt(VA->getSizeExpr()); 1343 1344 // Remove variable from local scope. 1345 if (ScopePos && VD == *ScopePos) 1346 ++ScopePos; 1347 1348 return Block; 1349} 1350 1351CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1352 // We may see an if statement in the middle of a basic block, or it may be the 1353 // first statement we are processing. In either case, we create a new basic 1354 // block. First, we create the blocks for the then...else statements, and 1355 // then we create the block containing the if statement. If we were in the 1356 // middle of a block, we stop processing that block. That block is then the 1357 // implicit successor for the "then" and "else" clauses. 1358 1359 // Save local scope position because in case of condition variable ScopePos 1360 // won't be restored when traversing AST. 1361 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1362 1363 // Create local scope for possible condition variable. 1364 // Store scope position. Add implicit destructor. 1365 if (VarDecl* VD = I->getConditionVariable()) { 1366 LocalScope::const_iterator BeginScopePos = ScopePos; 1367 addLocalScopeForVarDecl(VD); 1368 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1369 } 1370 1371 // The block we were proccessing is now finished. Make it the successor 1372 // block. 1373 if (Block) { 1374 Succ = Block; 1375 if (badCFG) 1376 return 0; 1377 } 1378 1379 // Process the false branch. 1380 CFGBlock* ElseBlock = Succ; 1381 1382 if (Stmt* Else = I->getElse()) { 1383 SaveAndRestore<CFGBlock*> sv(Succ); 1384 1385 // NULL out Block so that the recursive call to Visit will 1386 // create a new basic block. 1387 Block = NULL; 1388 1389 // If branch is not a compound statement create implicit scope 1390 // and add destructors. 1391 if (!isa<CompoundStmt>(Else)) 1392 addLocalScopeAndDtors(Else); 1393 1394 ElseBlock = addStmt(Else); 1395 1396 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1397 ElseBlock = sv.get(); 1398 else if (Block) { 1399 if (badCFG) 1400 return 0; 1401 } 1402 } 1403 1404 // Process the true branch. 1405 CFGBlock* ThenBlock; 1406 { 1407 Stmt* Then = I->getThen(); 1408 assert(Then); 1409 SaveAndRestore<CFGBlock*> sv(Succ); 1410 Block = NULL; 1411 1412 // If branch is not a compound statement create implicit scope 1413 // and add destructors. 1414 if (!isa<CompoundStmt>(Then)) 1415 addLocalScopeAndDtors(Then); 1416 1417 ThenBlock = addStmt(Then); 1418 1419 if (!ThenBlock) { 1420 // We can reach here if the "then" body has all NullStmts. 1421 // Create an empty block so we can distinguish between true and false 1422 // branches in path-sensitive analyses. 1423 ThenBlock = createBlock(false); 1424 addSuccessor(ThenBlock, sv.get()); 1425 } else if (Block) { 1426 if (badCFG) 1427 return 0; 1428 } 1429 } 1430 1431 // Now create a new block containing the if statement. 1432 Block = createBlock(false); 1433 1434 // Set the terminator of the new block to the If statement. 1435 Block->setTerminator(I); 1436 1437 // See if this is a known constant. 1438 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1439 1440 // Now add the successors. 1441 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1442 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1443 1444 // Add the condition as the last statement in the new block. This may create 1445 // new blocks as the condition may contain control-flow. Any newly created 1446 // blocks will be pointed to be "Block". 1447 Block = addStmt(I->getCond()); 1448 1449 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1450 // and the condition variable initialization to the CFG. 1451 if (VarDecl *VD = I->getConditionVariable()) { 1452 if (Expr *Init = VD->getInit()) { 1453 autoCreateBlock(); 1454 appendStmt(Block, I); 1455 addStmt(Init); 1456 } 1457 } 1458 1459 return Block; 1460} 1461 1462 1463CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1464 // If we were in the middle of a block we stop processing that block. 1465 // 1466 // NOTE: If a "return" appears in the middle of a block, this means that the 1467 // code afterwards is DEAD (unreachable). We still keep a basic block 1468 // for that code; a simple "mark-and-sweep" from the entry block will be 1469 // able to report such dead blocks. 1470 1471 // Create the new block. 1472 Block = createBlock(false); 1473 1474 // The Exit block is the only successor. 1475 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1476 addSuccessor(Block, &cfg->getExit()); 1477 1478 // Add the return statement to the block. This may create new blocks if R 1479 // contains control-flow (short-circuit operations). 1480 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1481} 1482 1483CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1484 // Get the block of the labeled statement. Add it to our map. 1485 addStmt(L->getSubStmt()); 1486 CFGBlock *LabelBlock = Block; 1487 1488 if (!LabelBlock) // This can happen when the body is empty, i.e. 1489 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1490 1491 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1492 "label already in map"); 1493 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1494 1495 // Labels partition blocks, so this is the end of the basic block we were 1496 // processing (L is the block's label). Because this is label (and we have 1497 // already processed the substatement) there is no extra control-flow to worry 1498 // about. 1499 LabelBlock->setLabel(L); 1500 if (badCFG) 1501 return 0; 1502 1503 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1504 Block = NULL; 1505 1506 // This block is now the implicit successor of other blocks. 1507 Succ = LabelBlock; 1508 1509 return LabelBlock; 1510} 1511 1512CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1513 // Goto is a control-flow statement. Thus we stop processing the current 1514 // block and create a new one. 1515 1516 Block = createBlock(false); 1517 Block->setTerminator(G); 1518 1519 // If we already know the mapping to the label block add the successor now. 1520 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1521 1522 if (I == LabelMap.end()) 1523 // We will need to backpatch this block later. 1524 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1525 else { 1526 JumpTarget JT = I->second; 1527 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1528 addSuccessor(Block, JT.block); 1529 } 1530 1531 return Block; 1532} 1533 1534CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1535 CFGBlock* LoopSuccessor = NULL; 1536 1537 // Save local scope position because in case of condition variable ScopePos 1538 // won't be restored when traversing AST. 1539 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1540 1541 // Create local scope for init statement and possible condition variable. 1542 // Add destructor for init statement and condition variable. 1543 // Store scope position for continue statement. 1544 if (Stmt* Init = F->getInit()) 1545 addLocalScopeForStmt(Init); 1546 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1547 1548 if (VarDecl* VD = F->getConditionVariable()) 1549 addLocalScopeForVarDecl(VD); 1550 LocalScope::const_iterator ContinueScopePos = ScopePos; 1551 1552 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1553 1554 // "for" is a control-flow statement. Thus we stop processing the current 1555 // block. 1556 if (Block) { 1557 if (badCFG) 1558 return 0; 1559 LoopSuccessor = Block; 1560 } else 1561 LoopSuccessor = Succ; 1562 1563 // Save the current value for the break targets. 1564 // All breaks should go to the code following the loop. 1565 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1566 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1567 1568 // Because of short-circuit evaluation, the condition of the loop can span 1569 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1570 // evaluate the condition. 1571 CFGBlock* ExitConditionBlock = createBlock(false); 1572 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1573 1574 // Set the terminator for the "exit" condition block. 1575 ExitConditionBlock->setTerminator(F); 1576 1577 // Now add the actual condition to the condition block. Because the condition 1578 // itself may contain control-flow, new blocks may be created. 1579 if (Stmt* C = F->getCond()) { 1580 Block = ExitConditionBlock; 1581 EntryConditionBlock = addStmt(C); 1582 if (badCFG) 1583 return 0; 1584 assert(Block == EntryConditionBlock || 1585 (Block == 0 && EntryConditionBlock == Succ)); 1586 1587 // If this block contains a condition variable, add both the condition 1588 // variable and initializer to the CFG. 1589 if (VarDecl *VD = F->getConditionVariable()) { 1590 if (Expr *Init = VD->getInit()) { 1591 autoCreateBlock(); 1592 appendStmt(Block, F); 1593 EntryConditionBlock = addStmt(Init); 1594 assert(Block == EntryConditionBlock); 1595 } 1596 } 1597 1598 if (Block) { 1599 if (badCFG) 1600 return 0; 1601 } 1602 } 1603 1604 // The condition block is the implicit successor for the loop body as well as 1605 // any code above the loop. 1606 Succ = EntryConditionBlock; 1607 1608 // See if this is a known constant. 1609 TryResult KnownVal(true); 1610 1611 if (F->getCond()) 1612 KnownVal = tryEvaluateBool(F->getCond()); 1613 1614 // Now create the loop body. 1615 { 1616 assert(F->getBody()); 1617 1618 // Save the current values for Block, Succ, and continue targets. 1619 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1620 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1621 1622 // Create a new block to contain the (bottom) of the loop body. 1623 Block = NULL; 1624 1625 // Loop body should end with destructor of Condition variable (if any). 1626 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1627 1628 if (Stmt* I = F->getInc()) { 1629 // Generate increment code in its own basic block. This is the target of 1630 // continue statements. 1631 Succ = addStmt(I); 1632 } else { 1633 // No increment code. Create a special, empty, block that is used as the 1634 // target block for "looping back" to the start of the loop. 1635 assert(Succ == EntryConditionBlock); 1636 Succ = Block ? Block : createBlock(); 1637 } 1638 1639 // Finish up the increment (or empty) block if it hasn't been already. 1640 if (Block) { 1641 assert(Block == Succ); 1642 if (badCFG) 1643 return 0; 1644 Block = 0; 1645 } 1646 1647 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1648 1649 // The starting block for the loop increment is the block that should 1650 // represent the 'loop target' for looping back to the start of the loop. 1651 ContinueJumpTarget.block->setLoopTarget(F); 1652 1653 // If body is not a compound statement create implicit scope 1654 // and add destructors. 1655 if (!isa<CompoundStmt>(F->getBody())) 1656 addLocalScopeAndDtors(F->getBody()); 1657 1658 // Now populate the body block, and in the process create new blocks as we 1659 // walk the body of the loop. 1660 CFGBlock* BodyBlock = addStmt(F->getBody()); 1661 1662 if (!BodyBlock) 1663 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1664 else if (badCFG) 1665 return 0; 1666 1667 // This new body block is a successor to our "exit" condition block. 1668 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1669 } 1670 1671 // Link up the condition block with the code that follows the loop. (the 1672 // false branch). 1673 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1674 1675 // If the loop contains initialization, create a new block for those 1676 // statements. This block can also contain statements that precede the loop. 1677 if (Stmt* I = F->getInit()) { 1678 Block = createBlock(); 1679 return addStmt(I); 1680 } 1681 1682 // There is no loop initialization. We are thus basically a while loop. 1683 // NULL out Block to force lazy block construction. 1684 Block = NULL; 1685 Succ = EntryConditionBlock; 1686 return EntryConditionBlock; 1687} 1688 1689CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1690 if (asc.alwaysAdd(*this, M)) { 1691 autoCreateBlock(); 1692 appendStmt(Block, M); 1693 } 1694 return Visit(M->getBase()); 1695} 1696 1697CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1698 // Objective-C fast enumeration 'for' statements: 1699 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1700 // 1701 // for ( Type newVariable in collection_expression ) { statements } 1702 // 1703 // becomes: 1704 // 1705 // prologue: 1706 // 1. collection_expression 1707 // T. jump to loop_entry 1708 // loop_entry: 1709 // 1. side-effects of element expression 1710 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1711 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1712 // TB: 1713 // statements 1714 // T. jump to loop_entry 1715 // FB: 1716 // what comes after 1717 // 1718 // and 1719 // 1720 // Type existingItem; 1721 // for ( existingItem in expression ) { statements } 1722 // 1723 // becomes: 1724 // 1725 // the same with newVariable replaced with existingItem; the binding works 1726 // the same except that for one ObjCForCollectionStmt::getElement() returns 1727 // a DeclStmt and the other returns a DeclRefExpr. 1728 // 1729 1730 CFGBlock* LoopSuccessor = 0; 1731 1732 if (Block) { 1733 if (badCFG) 1734 return 0; 1735 LoopSuccessor = Block; 1736 Block = 0; 1737 } else 1738 LoopSuccessor = Succ; 1739 1740 // Build the condition blocks. 1741 CFGBlock* ExitConditionBlock = createBlock(false); 1742 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1743 1744 // Set the terminator for the "exit" condition block. 1745 ExitConditionBlock->setTerminator(S); 1746 1747 // The last statement in the block should be the ObjCForCollectionStmt, which 1748 // performs the actual binding to 'element' and determines if there are any 1749 // more items in the collection. 1750 appendStmt(ExitConditionBlock, S); 1751 Block = ExitConditionBlock; 1752 1753 // Walk the 'element' expression to see if there are any side-effects. We 1754 // generate new blocks as necesary. We DON'T add the statement by default to 1755 // the CFG unless it contains control-flow. 1756 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1757 if (Block) { 1758 if (badCFG) 1759 return 0; 1760 Block = 0; 1761 } 1762 1763 // The condition block is the implicit successor for the loop body as well as 1764 // any code above the loop. 1765 Succ = EntryConditionBlock; 1766 1767 // Now create the true branch. 1768 { 1769 // Save the current values for Succ, continue and break targets. 1770 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1771 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1772 save_break(BreakJumpTarget); 1773 1774 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1775 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1776 1777 CFGBlock* BodyBlock = addStmt(S->getBody()); 1778 1779 if (!BodyBlock) 1780 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1781 else if (Block) { 1782 if (badCFG) 1783 return 0; 1784 } 1785 1786 // This new body block is a successor to our "exit" condition block. 1787 addSuccessor(ExitConditionBlock, BodyBlock); 1788 } 1789 1790 // Link up the condition block with the code that follows the loop. 1791 // (the false branch). 1792 addSuccessor(ExitConditionBlock, LoopSuccessor); 1793 1794 // Now create a prologue block to contain the collection expression. 1795 Block = createBlock(); 1796 return addStmt(S->getCollection()); 1797} 1798 1799CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1800 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1801 1802 // Inline the body. 1803 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1804 1805 // The sync body starts its own basic block. This makes it a little easier 1806 // for diagnostic clients. 1807 if (SyncBlock) { 1808 if (badCFG) 1809 return 0; 1810 1811 Block = 0; 1812 Succ = SyncBlock; 1813 } 1814 1815 // Add the @synchronized to the CFG. 1816 autoCreateBlock(); 1817 appendStmt(Block, S); 1818 1819 // Inline the sync expression. 1820 return addStmt(S->getSynchExpr()); 1821} 1822 1823CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1824 // FIXME 1825 return NYS(); 1826} 1827 1828CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1829 CFGBlock* LoopSuccessor = NULL; 1830 1831 // Save local scope position because in case of condition variable ScopePos 1832 // won't be restored when traversing AST. 1833 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1834 1835 // Create local scope for possible condition variable. 1836 // Store scope position for continue statement. 1837 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1838 if (VarDecl* VD = W->getConditionVariable()) { 1839 addLocalScopeForVarDecl(VD); 1840 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1841 } 1842 1843 // "while" is a control-flow statement. Thus we stop processing the current 1844 // block. 1845 if (Block) { 1846 if (badCFG) 1847 return 0; 1848 LoopSuccessor = Block; 1849 Block = 0; 1850 } else 1851 LoopSuccessor = Succ; 1852 1853 // Because of short-circuit evaluation, the condition of the loop can span 1854 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1855 // evaluate the condition. 1856 CFGBlock* ExitConditionBlock = createBlock(false); 1857 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1858 1859 // Set the terminator for the "exit" condition block. 1860 ExitConditionBlock->setTerminator(W); 1861 1862 // Now add the actual condition to the condition block. Because the condition 1863 // itself may contain control-flow, new blocks may be created. Thus we update 1864 // "Succ" after adding the condition. 1865 if (Stmt* C = W->getCond()) { 1866 Block = ExitConditionBlock; 1867 EntryConditionBlock = addStmt(C); 1868 // The condition might finish the current 'Block'. 1869 Block = EntryConditionBlock; 1870 1871 // If this block contains a condition variable, add both the condition 1872 // variable and initializer to the CFG. 1873 if (VarDecl *VD = W->getConditionVariable()) { 1874 if (Expr *Init = VD->getInit()) { 1875 autoCreateBlock(); 1876 appendStmt(Block, W); 1877 EntryConditionBlock = addStmt(Init); 1878 assert(Block == EntryConditionBlock); 1879 } 1880 } 1881 1882 if (Block) { 1883 if (badCFG) 1884 return 0; 1885 } 1886 } 1887 1888 // The condition block is the implicit successor for the loop body as well as 1889 // any code above the loop. 1890 Succ = EntryConditionBlock; 1891 1892 // See if this is a known constant. 1893 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1894 1895 // Process the loop body. 1896 { 1897 assert(W->getBody()); 1898 1899 // Save the current values for Block, Succ, and continue and break targets 1900 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1901 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1902 save_break(BreakJumpTarget); 1903 1904 // Create an empty block to represent the transition block for looping back 1905 // to the head of the loop. 1906 Block = 0; 1907 assert(Succ == EntryConditionBlock); 1908 Succ = createBlock(); 1909 Succ->setLoopTarget(W); 1910 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1911 1912 // All breaks should go to the code following the loop. 1913 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1914 1915 // NULL out Block to force lazy instantiation of blocks for the body. 1916 Block = NULL; 1917 1918 // Loop body should end with destructor of Condition variable (if any). 1919 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1920 1921 // If body is not a compound statement create implicit scope 1922 // and add destructors. 1923 if (!isa<CompoundStmt>(W->getBody())) 1924 addLocalScopeAndDtors(W->getBody()); 1925 1926 // Create the body. The returned block is the entry to the loop body. 1927 CFGBlock* BodyBlock = addStmt(W->getBody()); 1928 1929 if (!BodyBlock) 1930 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 1931 else if (Block) { 1932 if (badCFG) 1933 return 0; 1934 } 1935 1936 // Add the loop body entry as a successor to the condition. 1937 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1938 } 1939 1940 // Link up the condition block with the code that follows the loop. (the 1941 // false branch). 1942 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1943 1944 // There can be no more statements in the condition block since we loop back 1945 // to this block. NULL out Block to force lazy creation of another block. 1946 Block = NULL; 1947 1948 // Return the condition block, which is the dominating block for the loop. 1949 Succ = EntryConditionBlock; 1950 return EntryConditionBlock; 1951} 1952 1953 1954CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1955 // FIXME: For now we pretend that @catch and the code it contains does not 1956 // exit. 1957 return Block; 1958} 1959 1960CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1961 // FIXME: This isn't complete. We basically treat @throw like a return 1962 // statement. 1963 1964 // If we were in the middle of a block we stop processing that block. 1965 if (badCFG) 1966 return 0; 1967 1968 // Create the new block. 1969 Block = createBlock(false); 1970 1971 // The Exit block is the only successor. 1972 addSuccessor(Block, &cfg->getExit()); 1973 1974 // Add the statement to the block. This may create new blocks if S contains 1975 // control-flow (short-circuit operations). 1976 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1977} 1978 1979CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1980 // If we were in the middle of a block we stop processing that block. 1981 if (badCFG) 1982 return 0; 1983 1984 // Create the new block. 1985 Block = createBlock(false); 1986 1987 if (TryTerminatedBlock) 1988 // The current try statement is the only successor. 1989 addSuccessor(Block, TryTerminatedBlock); 1990 else 1991 // otherwise the Exit block is the only successor. 1992 addSuccessor(Block, &cfg->getExit()); 1993 1994 // Add the statement to the block. This may create new blocks if S contains 1995 // control-flow (short-circuit operations). 1996 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1997} 1998 1999CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 2000 CFGBlock* LoopSuccessor = NULL; 2001 2002 // "do...while" is a control-flow statement. Thus we stop processing the 2003 // current block. 2004 if (Block) { 2005 if (badCFG) 2006 return 0; 2007 LoopSuccessor = Block; 2008 } else 2009 LoopSuccessor = Succ; 2010 2011 // Because of short-circuit evaluation, the condition of the loop can span 2012 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2013 // evaluate the condition. 2014 CFGBlock* ExitConditionBlock = createBlock(false); 2015 CFGBlock* EntryConditionBlock = ExitConditionBlock; 2016 2017 // Set the terminator for the "exit" condition block. 2018 ExitConditionBlock->setTerminator(D); 2019 2020 // Now add the actual condition to the condition block. Because the condition 2021 // itself may contain control-flow, new blocks may be created. 2022 if (Stmt* C = D->getCond()) { 2023 Block = ExitConditionBlock; 2024 EntryConditionBlock = addStmt(C); 2025 if (Block) { 2026 if (badCFG) 2027 return 0; 2028 } 2029 } 2030 2031 // The condition block is the implicit successor for the loop body. 2032 Succ = EntryConditionBlock; 2033 2034 // See if this is a known constant. 2035 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2036 2037 // Process the loop body. 2038 CFGBlock* BodyBlock = NULL; 2039 { 2040 assert(D->getBody()); 2041 2042 // Save the current values for Block, Succ, and continue and break targets 2043 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2044 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2045 save_break(BreakJumpTarget); 2046 2047 // All continues within this loop should go to the condition block 2048 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2049 2050 // All breaks should go to the code following the loop. 2051 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2052 2053 // NULL out Block to force lazy instantiation of blocks for the body. 2054 Block = NULL; 2055 2056 // If body is not a compound statement create implicit scope 2057 // and add destructors. 2058 if (!isa<CompoundStmt>(D->getBody())) 2059 addLocalScopeAndDtors(D->getBody()); 2060 2061 // Create the body. The returned block is the entry to the loop body. 2062 BodyBlock = addStmt(D->getBody()); 2063 2064 if (!BodyBlock) 2065 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2066 else if (Block) { 2067 if (badCFG) 2068 return 0; 2069 } 2070 2071 if (!KnownVal.isFalse()) { 2072 // Add an intermediate block between the BodyBlock and the 2073 // ExitConditionBlock to represent the "loop back" transition. Create an 2074 // empty block to represent the transition block for looping back to the 2075 // head of the loop. 2076 // FIXME: Can we do this more efficiently without adding another block? 2077 Block = NULL; 2078 Succ = BodyBlock; 2079 CFGBlock *LoopBackBlock = createBlock(); 2080 LoopBackBlock->setLoopTarget(D); 2081 2082 // Add the loop body entry as a successor to the condition. 2083 addSuccessor(ExitConditionBlock, LoopBackBlock); 2084 } 2085 else 2086 addSuccessor(ExitConditionBlock, NULL); 2087 } 2088 2089 // Link up the condition block with the code that follows the loop. 2090 // (the false branch). 2091 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2092 2093 // There can be no more statements in the body block(s) since we loop back to 2094 // the body. NULL out Block to force lazy creation of another block. 2095 Block = NULL; 2096 2097 // Return the loop body, which is the dominating block for the loop. 2098 Succ = BodyBlock; 2099 return BodyBlock; 2100} 2101 2102CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2103 // "continue" is a control-flow statement. Thus we stop processing the 2104 // current block. 2105 if (badCFG) 2106 return 0; 2107 2108 // Now create a new block that ends with the continue statement. 2109 Block = createBlock(false); 2110 Block->setTerminator(C); 2111 2112 // If there is no target for the continue, then we are looking at an 2113 // incomplete AST. This means the CFG cannot be constructed. 2114 if (ContinueJumpTarget.block) { 2115 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2116 addSuccessor(Block, ContinueJumpTarget.block); 2117 } else 2118 badCFG = true; 2119 2120 return Block; 2121} 2122 2123CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 2124 AddStmtChoice asc) { 2125 2126 if (asc.alwaysAdd(*this, E)) { 2127 autoCreateBlock(); 2128 appendStmt(Block, E); 2129 } 2130 2131 // VLA types have expressions that must be evaluated. 2132 if (E->isArgumentType()) { 2133 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2134 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2135 addStmt(VA->getSizeExpr()); 2136 } 2137 2138 return Block; 2139} 2140 2141/// VisitStmtExpr - Utility method to handle (nested) statement 2142/// expressions (a GCC extension). 2143CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2144 if (asc.alwaysAdd(*this, SE)) { 2145 autoCreateBlock(); 2146 appendStmt(Block, SE); 2147 } 2148 return VisitCompoundStmt(SE->getSubStmt()); 2149} 2150 2151CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2152 // "switch" is a control-flow statement. Thus we stop processing the current 2153 // block. 2154 CFGBlock* SwitchSuccessor = NULL; 2155 2156 // Save local scope position because in case of condition variable ScopePos 2157 // won't be restored when traversing AST. 2158 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2159 2160 // Create local scope for possible condition variable. 2161 // Store scope position. Add implicit destructor. 2162 if (VarDecl* VD = Terminator->getConditionVariable()) { 2163 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2164 addLocalScopeForVarDecl(VD); 2165 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2166 } 2167 2168 if (Block) { 2169 if (badCFG) 2170 return 0; 2171 SwitchSuccessor = Block; 2172 } else SwitchSuccessor = Succ; 2173 2174 // Save the current "switch" context. 2175 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2176 save_default(DefaultCaseBlock); 2177 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2178 2179 // Set the "default" case to be the block after the switch statement. If the 2180 // switch statement contains a "default:", this value will be overwritten with 2181 // the block for that code. 2182 DefaultCaseBlock = SwitchSuccessor; 2183 2184 // Create a new block that will contain the switch statement. 2185 SwitchTerminatedBlock = createBlock(false); 2186 2187 // Now process the switch body. The code after the switch is the implicit 2188 // successor. 2189 Succ = SwitchSuccessor; 2190 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2191 2192 // When visiting the body, the case statements should automatically get linked 2193 // up to the switch. We also don't keep a pointer to the body, since all 2194 // control-flow from the switch goes to case/default statements. 2195 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2196 Block = NULL; 2197 2198 // For pruning unreachable case statements, save the current state 2199 // for tracking the condition value. 2200 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2201 false); 2202 2203 // Determine if the switch condition can be explicitly evaluated. 2204 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2205 Expr::EvalResult result; 2206 tryEvaluate(Terminator->getCond(), result); 2207 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, &result); 2208 2209 // If body is not a compound statement create implicit scope 2210 // and add destructors. 2211 if (!isa<CompoundStmt>(Terminator->getBody())) 2212 addLocalScopeAndDtors(Terminator->getBody()); 2213 2214 addStmt(Terminator->getBody()); 2215 if (Block) { 2216 if (badCFG) 2217 return 0; 2218 } 2219 2220 // If we have no "default:" case, the default transition is to the code 2221 // following the switch body. 2222 addSuccessor(SwitchTerminatedBlock, 2223 switchExclusivelyCovered ? 0 : DefaultCaseBlock); 2224 2225 // Add the terminator and condition in the switch block. 2226 SwitchTerminatedBlock->setTerminator(Terminator); 2227 Block = SwitchTerminatedBlock; 2228 Block = addStmt(Terminator->getCond()); 2229 2230 // Finally, if the SwitchStmt contains a condition variable, add both the 2231 // SwitchStmt and the condition variable initialization to the CFG. 2232 if (VarDecl *VD = Terminator->getConditionVariable()) { 2233 if (Expr *Init = VD->getInit()) { 2234 autoCreateBlock(); 2235 appendStmt(Block, Terminator); 2236 addStmt(Init); 2237 } 2238 } 2239 2240 return Block; 2241} 2242 2243static bool shouldAddCase(bool &switchExclusivelyCovered, 2244 const Expr::EvalResult &switchCond, 2245 const CaseStmt *CS, 2246 ASTContext &Ctx) { 2247 bool addCase = false; 2248 2249 if (!switchExclusivelyCovered) { 2250 if (switchCond.Val.isInt()) { 2251 // Evaluate the LHS of the case value. 2252 Expr::EvalResult V1; 2253 CS->getLHS()->Evaluate(V1, Ctx); 2254 assert(V1.Val.isInt()); 2255 const llvm::APSInt &condInt = switchCond.Val.getInt(); 2256 const llvm::APSInt &lhsInt = V1.Val.getInt(); 2257 2258 if (condInt == lhsInt) { 2259 addCase = true; 2260 switchExclusivelyCovered = true; 2261 } 2262 else if (condInt < lhsInt) { 2263 if (const Expr *RHS = CS->getRHS()) { 2264 // Evaluate the RHS of the case value. 2265 Expr::EvalResult V2; 2266 RHS->Evaluate(V2, Ctx); 2267 assert(V2.Val.isInt()); 2268 if (V2.Val.getInt() <= condInt) { 2269 addCase = true; 2270 switchExclusivelyCovered = true; 2271 } 2272 } 2273 } 2274 } 2275 else 2276 addCase = true; 2277 } 2278 return addCase; 2279} 2280 2281CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2282 // CaseStmts are essentially labels, so they are the first statement in a 2283 // block. 2284 CFGBlock *TopBlock = 0, *LastBlock = 0; 2285 assert(switchCond); 2286 2287 if (Stmt *Sub = CS->getSubStmt()) { 2288 // For deeply nested chains of CaseStmts, instead of doing a recursion 2289 // (which can blow out the stack), manually unroll and create blocks 2290 // along the way. 2291 while (isa<CaseStmt>(Sub)) { 2292 CFGBlock *currentBlock = createBlock(false); 2293 currentBlock->setLabel(CS); 2294 2295 if (TopBlock) 2296 addSuccessor(LastBlock, currentBlock); 2297 else 2298 TopBlock = currentBlock; 2299 2300 addSuccessor(SwitchTerminatedBlock, 2301 shouldAddCase(switchExclusivelyCovered, *switchCond, 2302 CS, *Context) 2303 ? currentBlock : 0); 2304 2305 LastBlock = currentBlock; 2306 CS = cast<CaseStmt>(Sub); 2307 Sub = CS->getSubStmt(); 2308 } 2309 2310 addStmt(Sub); 2311 } 2312 2313 CFGBlock* CaseBlock = Block; 2314 if (!CaseBlock) 2315 CaseBlock = createBlock(); 2316 2317 // Cases statements partition blocks, so this is the top of the basic block we 2318 // were processing (the "case XXX:" is the label). 2319 CaseBlock->setLabel(CS); 2320 2321 if (badCFG) 2322 return 0; 2323 2324 // Add this block to the list of successors for the block with the switch 2325 // statement. 2326 assert(SwitchTerminatedBlock); 2327 addSuccessor(SwitchTerminatedBlock, 2328 shouldAddCase(switchExclusivelyCovered, *switchCond, 2329 CS, *Context) 2330 ? CaseBlock : 0); 2331 2332 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2333 Block = NULL; 2334 2335 if (TopBlock) { 2336 addSuccessor(LastBlock, CaseBlock); 2337 Succ = TopBlock; 2338 } else { 2339 // This block is now the implicit successor of other blocks. 2340 Succ = CaseBlock; 2341 } 2342 2343 return Succ; 2344} 2345 2346CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2347 if (Terminator->getSubStmt()) 2348 addStmt(Terminator->getSubStmt()); 2349 2350 DefaultCaseBlock = Block; 2351 2352 if (!DefaultCaseBlock) 2353 DefaultCaseBlock = createBlock(); 2354 2355 // Default statements partition blocks, so this is the top of the basic block 2356 // we were processing (the "default:" is the label). 2357 DefaultCaseBlock->setLabel(Terminator); 2358 2359 if (badCFG) 2360 return 0; 2361 2362 // Unlike case statements, we don't add the default block to the successors 2363 // for the switch statement immediately. This is done when we finish 2364 // processing the switch statement. This allows for the default case 2365 // (including a fall-through to the code after the switch statement) to always 2366 // be the last successor of a switch-terminated block. 2367 2368 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2369 Block = NULL; 2370 2371 // This block is now the implicit successor of other blocks. 2372 Succ = DefaultCaseBlock; 2373 2374 return DefaultCaseBlock; 2375} 2376 2377CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2378 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2379 // current block. 2380 CFGBlock* TrySuccessor = NULL; 2381 2382 if (Block) { 2383 if (badCFG) 2384 return 0; 2385 TrySuccessor = Block; 2386 } else TrySuccessor = Succ; 2387 2388 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2389 2390 // Create a new block that will contain the try statement. 2391 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2392 // Add the terminator in the try block. 2393 NewTryTerminatedBlock->setTerminator(Terminator); 2394 2395 bool HasCatchAll = false; 2396 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2397 // The code after the try is the implicit successor. 2398 Succ = TrySuccessor; 2399 CXXCatchStmt *CS = Terminator->getHandler(h); 2400 if (CS->getExceptionDecl() == 0) { 2401 HasCatchAll = true; 2402 } 2403 Block = NULL; 2404 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2405 if (CatchBlock == 0) 2406 return 0; 2407 // Add this block to the list of successors for the block with the try 2408 // statement. 2409 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2410 } 2411 if (!HasCatchAll) { 2412 if (PrevTryTerminatedBlock) 2413 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2414 else 2415 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2416 } 2417 2418 // The code after the try is the implicit successor. 2419 Succ = TrySuccessor; 2420 2421 // Save the current "try" context. 2422 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2423 TryTerminatedBlock = NewTryTerminatedBlock; 2424 2425 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2426 Block = NULL; 2427 Block = addStmt(Terminator->getTryBlock()); 2428 return Block; 2429} 2430 2431CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2432 // CXXCatchStmt are treated like labels, so they are the first statement in a 2433 // block. 2434 2435 // Save local scope position because in case of exception variable ScopePos 2436 // won't be restored when traversing AST. 2437 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2438 2439 // Create local scope for possible exception variable. 2440 // Store scope position. Add implicit destructor. 2441 if (VarDecl* VD = CS->getExceptionDecl()) { 2442 LocalScope::const_iterator BeginScopePos = ScopePos; 2443 addLocalScopeForVarDecl(VD); 2444 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2445 } 2446 2447 if (CS->getHandlerBlock()) 2448 addStmt(CS->getHandlerBlock()); 2449 2450 CFGBlock* CatchBlock = Block; 2451 if (!CatchBlock) 2452 CatchBlock = createBlock(); 2453 2454 CatchBlock->setLabel(CS); 2455 2456 if (badCFG) 2457 return 0; 2458 2459 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2460 Block = NULL; 2461 2462 return CatchBlock; 2463} 2464 2465CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2466 AddStmtChoice asc) { 2467 if (BuildOpts.AddImplicitDtors) { 2468 // If adding implicit destructors visit the full expression for adding 2469 // destructors of temporaries. 2470 VisitForTemporaryDtors(E->getSubExpr()); 2471 2472 // Full expression has to be added as CFGStmt so it will be sequenced 2473 // before destructors of it's temporaries. 2474 asc = asc.withAlwaysAdd(true); 2475 } 2476 return Visit(E->getSubExpr(), asc); 2477} 2478 2479CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2480 AddStmtChoice asc) { 2481 if (asc.alwaysAdd(*this, E)) { 2482 autoCreateBlock(); 2483 appendStmt(Block, E); 2484 2485 // We do not want to propagate the AlwaysAdd property. 2486 asc = asc.withAlwaysAdd(false); 2487 } 2488 return Visit(E->getSubExpr(), asc); 2489} 2490 2491CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2492 AddStmtChoice asc) { 2493 autoCreateBlock(); 2494 if (!C->isElidable()) 2495 appendStmt(Block, C); 2496 2497 return VisitChildren(C); 2498} 2499 2500CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2501 AddStmtChoice asc) { 2502 if (asc.alwaysAdd(*this, E)) { 2503 autoCreateBlock(); 2504 appendStmt(Block, E); 2505 // We do not want to propagate the AlwaysAdd property. 2506 asc = asc.withAlwaysAdd(false); 2507 } 2508 return Visit(E->getSubExpr(), asc); 2509} 2510 2511CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2512 AddStmtChoice asc) { 2513 autoCreateBlock(); 2514 appendStmt(Block, C); 2515 return VisitChildren(C); 2516} 2517 2518CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2519 AddStmtChoice asc) { 2520 autoCreateBlock(); 2521 appendStmt(Block, C); 2522 return VisitChildren(C); 2523} 2524 2525CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2526 AddStmtChoice asc) { 2527 if (asc.alwaysAdd(*this, E)) { 2528 autoCreateBlock(); 2529 appendStmt(Block, E); 2530 } 2531 return Visit(E->getSubExpr(), AddStmtChoice()); 2532} 2533 2534CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2535 // Lazily create the indirect-goto dispatch block if there isn't one already. 2536 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2537 2538 if (!IBlock) { 2539 IBlock = createBlock(false); 2540 cfg->setIndirectGotoBlock(IBlock); 2541 } 2542 2543 // IndirectGoto is a control-flow statement. Thus we stop processing the 2544 // current block and create a new one. 2545 if (badCFG) 2546 return 0; 2547 2548 Block = createBlock(false); 2549 Block->setTerminator(I); 2550 addSuccessor(Block, IBlock); 2551 return addStmt(I->getTarget()); 2552} 2553 2554CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2555tryAgain: 2556 if (!E) { 2557 badCFG = true; 2558 return NULL; 2559 } 2560 switch (E->getStmtClass()) { 2561 default: 2562 return VisitChildrenForTemporaryDtors(E); 2563 2564 case Stmt::BinaryOperatorClass: 2565 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2566 2567 case Stmt::CXXBindTemporaryExprClass: 2568 return VisitCXXBindTemporaryExprForTemporaryDtors( 2569 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2570 2571 case Stmt::BinaryConditionalOperatorClass: 2572 case Stmt::ConditionalOperatorClass: 2573 return VisitConditionalOperatorForTemporaryDtors( 2574 cast<AbstractConditionalOperator>(E), BindToTemporary); 2575 2576 case Stmt::ImplicitCastExprClass: 2577 // For implicit cast we want BindToTemporary to be passed further. 2578 E = cast<CastExpr>(E)->getSubExpr(); 2579 goto tryAgain; 2580 2581 case Stmt::ParenExprClass: 2582 E = cast<ParenExpr>(E)->getSubExpr(); 2583 goto tryAgain; 2584 } 2585} 2586 2587CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2588 // When visiting children for destructors we want to visit them in reverse 2589 // order. Because there's no reverse iterator for children must to reverse 2590 // them in helper vector. 2591 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2592 ChildrenVect ChildrenRev; 2593 for (Stmt::child_range I = E->children(); I; ++I) { 2594 if (*I) ChildrenRev.push_back(*I); 2595 } 2596 2597 CFGBlock *B = Block; 2598 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2599 L = ChildrenRev.rend(); I != L; ++I) { 2600 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2601 B = R; 2602 } 2603 return B; 2604} 2605 2606CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2607 if (E->isLogicalOp()) { 2608 // Destructors for temporaries in LHS expression should be called after 2609 // those for RHS expression. Even if this will unnecessarily create a block, 2610 // this block will be used at least by the full expression. 2611 autoCreateBlock(); 2612 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2613 if (badCFG) 2614 return NULL; 2615 2616 Succ = ConfluenceBlock; 2617 Block = NULL; 2618 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2619 2620 if (RHSBlock) { 2621 if (badCFG) 2622 return NULL; 2623 2624 // If RHS expression did produce destructors we need to connect created 2625 // blocks to CFG in same manner as for binary operator itself. 2626 CFGBlock *LHSBlock = createBlock(false); 2627 LHSBlock->setTerminator(CFGTerminator(E, true)); 2628 2629 // For binary operator LHS block is before RHS in list of predecessors 2630 // of ConfluenceBlock. 2631 std::reverse(ConfluenceBlock->pred_begin(), 2632 ConfluenceBlock->pred_end()); 2633 2634 // See if this is a known constant. 2635 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2636 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2637 KnownVal.negate(); 2638 2639 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2640 // itself. 2641 if (E->getOpcode() == BO_LOr) { 2642 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2643 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2644 } else { 2645 assert (E->getOpcode() == BO_LAnd); 2646 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2647 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2648 } 2649 2650 Block = LHSBlock; 2651 return LHSBlock; 2652 } 2653 2654 Block = ConfluenceBlock; 2655 return ConfluenceBlock; 2656 } 2657 2658 if (E->isAssignmentOp()) { 2659 // For assignment operator (=) LHS expression is visited 2660 // before RHS expression. For destructors visit them in reverse order. 2661 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2662 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2663 return LHSBlock ? LHSBlock : RHSBlock; 2664 } 2665 2666 // For any other binary operator RHS expression is visited before 2667 // LHS expression (order of children). For destructors visit them in reverse 2668 // order. 2669 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2670 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2671 return RHSBlock ? RHSBlock : LHSBlock; 2672} 2673 2674CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2675 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2676 // First add destructors for temporaries in subexpression. 2677 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2678 if (!BindToTemporary) { 2679 // If lifetime of temporary is not prolonged (by assigning to constant 2680 // reference) add destructor for it. 2681 autoCreateBlock(); 2682 appendTemporaryDtor(Block, E); 2683 B = Block; 2684 } 2685 return B; 2686} 2687 2688CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2689 AbstractConditionalOperator *E, bool BindToTemporary) { 2690 // First add destructors for condition expression. Even if this will 2691 // unnecessarily create a block, this block will be used at least by the full 2692 // expression. 2693 autoCreateBlock(); 2694 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2695 if (badCFG) 2696 return NULL; 2697 if (BinaryConditionalOperator *BCO 2698 = dyn_cast<BinaryConditionalOperator>(E)) { 2699 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2700 if (badCFG) 2701 return NULL; 2702 } 2703 2704 // Try to add block with destructors for LHS expression. 2705 CFGBlock *LHSBlock = NULL; 2706 Succ = ConfluenceBlock; 2707 Block = NULL; 2708 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2709 if (badCFG) 2710 return NULL; 2711 2712 // Try to add block with destructors for RHS expression; 2713 Succ = ConfluenceBlock; 2714 Block = NULL; 2715 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2716 BindToTemporary); 2717 if (badCFG) 2718 return NULL; 2719 2720 if (!RHSBlock && !LHSBlock) { 2721 // If neither LHS nor RHS expression had temporaries to destroy don't create 2722 // more blocks. 2723 Block = ConfluenceBlock; 2724 return Block; 2725 } 2726 2727 Block = createBlock(false); 2728 Block->setTerminator(CFGTerminator(E, true)); 2729 2730 // See if this is a known constant. 2731 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2732 2733 if (LHSBlock) { 2734 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2735 } else if (KnownVal.isFalse()) { 2736 addSuccessor(Block, NULL); 2737 } else { 2738 addSuccessor(Block, ConfluenceBlock); 2739 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2740 } 2741 2742 if (!RHSBlock) 2743 RHSBlock = ConfluenceBlock; 2744 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2745 2746 return Block; 2747} 2748 2749} // end anonymous namespace 2750 2751/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2752/// no successors or predecessors. If this is the first block created in the 2753/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2754CFGBlock* CFG::createBlock() { 2755 bool first_block = begin() == end(); 2756 2757 // Create the block. 2758 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2759 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2760 Blocks.push_back(Mem, BlkBVC); 2761 2762 // If this is the first block, set it as the Entry and Exit. 2763 if (first_block) 2764 Entry = Exit = &back(); 2765 2766 // Return the block. 2767 return &back(); 2768} 2769 2770/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2771/// CFG is returned to the caller. 2772CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2773 const BuildOptions &BO) { 2774 CFGBuilder Builder(C, BO); 2775 return Builder.buildCFG(D, Statement); 2776} 2777 2778const CXXDestructorDecl * 2779CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 2780 switch (getKind()) { 2781 case CFGElement::Invalid: 2782 case CFGElement::Statement: 2783 case CFGElement::Initializer: 2784 llvm_unreachable("getDestructorDecl should only be used with " 2785 "ImplicitDtors"); 2786 case CFGElement::AutomaticObjectDtor: { 2787 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 2788 QualType ty = var->getType(); 2789 ty = ty.getNonReferenceType(); 2790 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 2791 ty = arrayType->getElementType(); 2792 } 2793 const RecordType *recordType = ty->getAs<RecordType>(); 2794 const CXXRecordDecl *classDecl = 2795 cast<CXXRecordDecl>(recordType->getDecl()); 2796 return classDecl->getDestructor(); 2797 } 2798 case CFGElement::TemporaryDtor: { 2799 const CXXBindTemporaryExpr *bindExpr = 2800 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 2801 const CXXTemporary *temp = bindExpr->getTemporary(); 2802 return temp->getDestructor(); 2803 } 2804 case CFGElement::BaseDtor: 2805 case CFGElement::MemberDtor: 2806 2807 // Not yet supported. 2808 return 0; 2809 } 2810 llvm_unreachable("getKind() returned bogus value"); 2811 return 0; 2812} 2813 2814bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 2815 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 2816 QualType ty = cdecl->getType(); 2817 return cast<FunctionType>(ty)->getNoReturnAttr(); 2818 } 2819 return false; 2820} 2821 2822//===----------------------------------------------------------------------===// 2823// CFG: Queries for BlkExprs. 2824//===----------------------------------------------------------------------===// 2825 2826namespace { 2827 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2828} 2829 2830static void FindSubExprAssignments(Stmt *S, 2831 llvm::SmallPtrSet<Expr*,50>& Set) { 2832 if (!S) 2833 return; 2834 2835 for (Stmt::child_range I = S->children(); I; ++I) { 2836 Stmt *child = *I; 2837 if (!child) 2838 continue; 2839 2840 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2841 if (B->isAssignmentOp()) Set.insert(B); 2842 2843 FindSubExprAssignments(child, Set); 2844 } 2845} 2846 2847static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2848 BlkExprMapTy* M = new BlkExprMapTy(); 2849 2850 // Look for assignments that are used as subexpressions. These are the only 2851 // assignments that we want to *possibly* register as a block-level 2852 // expression. Basically, if an assignment occurs both in a subexpression and 2853 // at the block-level, it is a block-level expression. 2854 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2855 2856 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2857 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2858 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 2859 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 2860 2861 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2862 2863 // Iterate over the statements again on identify the Expr* and Stmt* at the 2864 // block-level that are block-level expressions. 2865 2866 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2867 const CFGStmt *CS = BI->getAs<CFGStmt>(); 2868 if (!CS) 2869 continue; 2870 if (Expr* Exp = dyn_cast<Expr>(CS->getStmt())) { 2871 2872 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2873 // Assignment expressions that are not nested within another 2874 // expression are really "statements" whose value is never used by 2875 // another expression. 2876 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2877 continue; 2878 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2879 // Special handling for statement expressions. The last statement in 2880 // the statement expression is also a block-level expr. 2881 const CompoundStmt* C = Terminator->getSubStmt(); 2882 if (!C->body_empty()) { 2883 unsigned x = M->size(); 2884 (*M)[C->body_back()] = x; 2885 } 2886 } 2887 2888 unsigned x = M->size(); 2889 (*M)[Exp] = x; 2890 } 2891 } 2892 2893 // Look at terminators. The condition is a block-level expression. 2894 2895 Stmt* S = (*I)->getTerminatorCondition(); 2896 2897 if (S && M->find(S) == M->end()) { 2898 unsigned x = M->size(); 2899 (*M)[S] = x; 2900 } 2901 } 2902 2903 return M; 2904} 2905 2906CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2907 assert(S != NULL); 2908 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2909 2910 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2911 BlkExprMapTy::iterator I = M->find(S); 2912 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2913} 2914 2915unsigned CFG::getNumBlkExprs() { 2916 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2917 return M->size(); 2918 2919 // We assume callers interested in the number of BlkExprs will want 2920 // the map constructed if it doesn't already exist. 2921 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2922 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2923} 2924 2925//===----------------------------------------------------------------------===// 2926// Filtered walking of the CFG. 2927//===----------------------------------------------------------------------===// 2928 2929bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2930 const CFGBlock *From, const CFGBlock *To) { 2931 2932 if (To && F.IgnoreDefaultsWithCoveredEnums) { 2933 // If the 'To' has no label or is labeled but the label isn't a 2934 // CaseStmt then filter this edge. 2935 if (const SwitchStmt *S = 2936 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 2937 if (S->isAllEnumCasesCovered()) { 2938 const Stmt *L = To->getLabel(); 2939 if (!L || !isa<CaseStmt>(L)) 2940 return true; 2941 } 2942 } 2943 } 2944 2945 return false; 2946} 2947 2948//===----------------------------------------------------------------------===// 2949// Cleanup: CFG dstor. 2950//===----------------------------------------------------------------------===// 2951 2952CFG::~CFG() { 2953 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2954} 2955 2956//===----------------------------------------------------------------------===// 2957// CFG pretty printing 2958//===----------------------------------------------------------------------===// 2959 2960namespace { 2961 2962class StmtPrinterHelper : public PrinterHelper { 2963 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2964 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2965 StmtMapTy StmtMap; 2966 DeclMapTy DeclMap; 2967 signed currentBlock; 2968 unsigned currentStmt; 2969 const LangOptions &LangOpts; 2970public: 2971 2972 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2973 : currentBlock(0), currentStmt(0), LangOpts(LO) 2974 { 2975 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2976 unsigned j = 1; 2977 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2978 BI != BEnd; ++BI, ++j ) { 2979 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 2980 const Stmt *stmt= SE->getStmt(); 2981 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2982 StmtMap[stmt] = P; 2983 2984 switch (stmt->getStmtClass()) { 2985 case Stmt::DeclStmtClass: 2986 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 2987 break; 2988 case Stmt::IfStmtClass: { 2989 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 2990 if (var) 2991 DeclMap[var] = P; 2992 break; 2993 } 2994 case Stmt::ForStmtClass: { 2995 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 2996 if (var) 2997 DeclMap[var] = P; 2998 break; 2999 } 3000 case Stmt::WhileStmtClass: { 3001 const VarDecl *var = 3002 cast<WhileStmt>(stmt)->getConditionVariable(); 3003 if (var) 3004 DeclMap[var] = P; 3005 break; 3006 } 3007 case Stmt::SwitchStmtClass: { 3008 const VarDecl *var = 3009 cast<SwitchStmt>(stmt)->getConditionVariable(); 3010 if (var) 3011 DeclMap[var] = P; 3012 break; 3013 } 3014 case Stmt::CXXCatchStmtClass: { 3015 const VarDecl *var = 3016 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3017 if (var) 3018 DeclMap[var] = P; 3019 break; 3020 } 3021 default: 3022 break; 3023 } 3024 } 3025 } 3026 } 3027 } 3028 3029 3030 virtual ~StmtPrinterHelper() {} 3031 3032 const LangOptions &getLangOpts() const { return LangOpts; } 3033 void setBlockID(signed i) { currentBlock = i; } 3034 void setStmtID(unsigned i) { currentStmt = i; } 3035 3036 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 3037 StmtMapTy::iterator I = StmtMap.find(S); 3038 3039 if (I == StmtMap.end()) 3040 return false; 3041 3042 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3043 && I->second.second == currentStmt) { 3044 return false; 3045 } 3046 3047 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3048 return true; 3049 } 3050 3051 bool handleDecl(const Decl* D, llvm::raw_ostream& OS) { 3052 DeclMapTy::iterator I = DeclMap.find(D); 3053 3054 if (I == DeclMap.end()) 3055 return false; 3056 3057 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3058 && I->second.second == currentStmt) { 3059 return false; 3060 } 3061 3062 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3063 return true; 3064 } 3065}; 3066} // end anonymous namespace 3067 3068 3069namespace { 3070class CFGBlockTerminatorPrint 3071 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3072 3073 llvm::raw_ostream& OS; 3074 StmtPrinterHelper* Helper; 3075 PrintingPolicy Policy; 3076public: 3077 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 3078 const PrintingPolicy &Policy) 3079 : OS(os), Helper(helper), Policy(Policy) {} 3080 3081 void VisitIfStmt(IfStmt* I) { 3082 OS << "if "; 3083 I->getCond()->printPretty(OS,Helper,Policy); 3084 } 3085 3086 // Default case. 3087 void VisitStmt(Stmt* Terminator) { 3088 Terminator->printPretty(OS, Helper, Policy); 3089 } 3090 3091 void VisitForStmt(ForStmt* F) { 3092 OS << "for (" ; 3093 if (F->getInit()) 3094 OS << "..."; 3095 OS << "; "; 3096 if (Stmt* C = F->getCond()) 3097 C->printPretty(OS, Helper, Policy); 3098 OS << "; "; 3099 if (F->getInc()) 3100 OS << "..."; 3101 OS << ")"; 3102 } 3103 3104 void VisitWhileStmt(WhileStmt* W) { 3105 OS << "while " ; 3106 if (Stmt* C = W->getCond()) 3107 C->printPretty(OS, Helper, Policy); 3108 } 3109 3110 void VisitDoStmt(DoStmt* D) { 3111 OS << "do ... while "; 3112 if (Stmt* C = D->getCond()) 3113 C->printPretty(OS, Helper, Policy); 3114 } 3115 3116 void VisitSwitchStmt(SwitchStmt* Terminator) { 3117 OS << "switch "; 3118 Terminator->getCond()->printPretty(OS, Helper, Policy); 3119 } 3120 3121 void VisitCXXTryStmt(CXXTryStmt* CS) { 3122 OS << "try ..."; 3123 } 3124 3125 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3126 C->getCond()->printPretty(OS, Helper, Policy); 3127 OS << " ? ... : ..."; 3128 } 3129 3130 void VisitChooseExpr(ChooseExpr* C) { 3131 OS << "__builtin_choose_expr( "; 3132 C->getCond()->printPretty(OS, Helper, Policy); 3133 OS << " )"; 3134 } 3135 3136 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 3137 OS << "goto *"; 3138 I->getTarget()->printPretty(OS, Helper, Policy); 3139 } 3140 3141 void VisitBinaryOperator(BinaryOperator* B) { 3142 if (!B->isLogicalOp()) { 3143 VisitExpr(B); 3144 return; 3145 } 3146 3147 B->getLHS()->printPretty(OS, Helper, Policy); 3148 3149 switch (B->getOpcode()) { 3150 case BO_LOr: 3151 OS << " || ..."; 3152 return; 3153 case BO_LAnd: 3154 OS << " && ..."; 3155 return; 3156 default: 3157 assert(false && "Invalid logical operator."); 3158 } 3159 } 3160 3161 void VisitExpr(Expr* E) { 3162 E->printPretty(OS, Helper, Policy); 3163 } 3164}; 3165} // end anonymous namespace 3166 3167static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3168 const CFGElement &E) { 3169 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3170 Stmt *S = CS->getStmt(); 3171 3172 if (Helper) { 3173 3174 // special printing for statement-expressions. 3175 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3176 CompoundStmt* Sub = SE->getSubStmt(); 3177 3178 if (Sub->children()) { 3179 OS << "({ ... ; "; 3180 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3181 OS << " })\n"; 3182 return; 3183 } 3184 } 3185 // special printing for comma expressions. 3186 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3187 if (B->getOpcode() == BO_Comma) { 3188 OS << "... , "; 3189 Helper->handledStmt(B->getRHS(),OS); 3190 OS << '\n'; 3191 return; 3192 } 3193 } 3194 } 3195 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3196 3197 if (isa<CXXOperatorCallExpr>(S)) { 3198 OS << " (OperatorCall)"; 3199 } else if (isa<CXXBindTemporaryExpr>(S)) { 3200 OS << " (BindTemporary)"; 3201 } 3202 3203 // Expressions need a newline. 3204 if (isa<Expr>(S)) 3205 OS << '\n'; 3206 3207 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3208 const CXXCtorInitializer *I = IE->getInitializer(); 3209 if (I->isBaseInitializer()) 3210 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3211 else OS << I->getAnyMember()->getName(); 3212 3213 OS << "("; 3214 if (Expr* IE = I->getInit()) 3215 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3216 OS << ")"; 3217 3218 if (I->isBaseInitializer()) 3219 OS << " (Base initializer)\n"; 3220 else OS << " (Member initializer)\n"; 3221 3222 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3223 const VarDecl* VD = DE->getVarDecl(); 3224 Helper->handleDecl(VD, OS); 3225 3226 const Type* T = VD->getType().getTypePtr(); 3227 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3228 T = RT->getPointeeType().getTypePtr(); 3229 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3230 T = ET; 3231 3232 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3233 OS << " (Implicit destructor)\n"; 3234 3235 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3236 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3237 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3238 OS << " (Base object destructor)\n"; 3239 3240 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3241 const FieldDecl *FD = ME->getFieldDecl(); 3242 3243 const Type *T = FD->getType().getTypePtr(); 3244 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3245 T = ET; 3246 3247 OS << "this->" << FD->getName(); 3248 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3249 OS << " (Member object destructor)\n"; 3250 3251 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3252 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3253 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3254 OS << " (Temporary object destructor)\n"; 3255 } 3256} 3257 3258static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3259 const CFGBlock& B, 3260 StmtPrinterHelper* Helper, bool print_edges) { 3261 3262 if (Helper) Helper->setBlockID(B.getBlockID()); 3263 3264 // Print the header. 3265 OS << "\n [ B" << B.getBlockID(); 3266 3267 if (&B == &cfg->getEntry()) 3268 OS << " (ENTRY) ]\n"; 3269 else if (&B == &cfg->getExit()) 3270 OS << " (EXIT) ]\n"; 3271 else if (&B == cfg->getIndirectGotoBlock()) 3272 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3273 else 3274 OS << " ]\n"; 3275 3276 // Print the label of this block. 3277 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3278 3279 if (print_edges) 3280 OS << " "; 3281 3282 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3283 OS << L->getName(); 3284 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3285 OS << "case "; 3286 C->getLHS()->printPretty(OS, Helper, 3287 PrintingPolicy(Helper->getLangOpts())); 3288 if (C->getRHS()) { 3289 OS << " ... "; 3290 C->getRHS()->printPretty(OS, Helper, 3291 PrintingPolicy(Helper->getLangOpts())); 3292 } 3293 } else if (isa<DefaultStmt>(Label)) 3294 OS << "default"; 3295 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3296 OS << "catch ("; 3297 if (CS->getExceptionDecl()) 3298 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3299 0); 3300 else 3301 OS << "..."; 3302 OS << ")"; 3303 3304 } else 3305 assert(false && "Invalid label statement in CFGBlock."); 3306 3307 OS << ":\n"; 3308 } 3309 3310 // Iterate through the statements in the block and print them. 3311 unsigned j = 1; 3312 3313 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3314 I != E ; ++I, ++j ) { 3315 3316 // Print the statement # in the basic block and the statement itself. 3317 if (print_edges) 3318 OS << " "; 3319 3320 OS << llvm::format("%3d", j) << ": "; 3321 3322 if (Helper) 3323 Helper->setStmtID(j); 3324 3325 print_elem(OS,Helper,*I); 3326 } 3327 3328 // Print the terminator of this block. 3329 if (B.getTerminator()) { 3330 if (print_edges) 3331 OS << " "; 3332 3333 OS << " T: "; 3334 3335 if (Helper) Helper->setBlockID(-1); 3336 3337 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3338 PrintingPolicy(Helper->getLangOpts())); 3339 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3340 OS << '\n'; 3341 } 3342 3343 if (print_edges) { 3344 // Print the predecessors of this block. 3345 OS << " Predecessors (" << B.pred_size() << "):"; 3346 unsigned i = 0; 3347 3348 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3349 I != E; ++I, ++i) { 3350 3351 if (i == 8 || (i-8) == 0) 3352 OS << "\n "; 3353 3354 OS << " B" << (*I)->getBlockID(); 3355 } 3356 3357 OS << '\n'; 3358 3359 // Print the successors of this block. 3360 OS << " Successors (" << B.succ_size() << "):"; 3361 i = 0; 3362 3363 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3364 I != E; ++I, ++i) { 3365 3366 if (i == 8 || (i-8) % 10 == 0) 3367 OS << "\n "; 3368 3369 if (*I) 3370 OS << " B" << (*I)->getBlockID(); 3371 else 3372 OS << " NULL"; 3373 } 3374 3375 OS << '\n'; 3376 } 3377} 3378 3379 3380/// dump - A simple pretty printer of a CFG that outputs to stderr. 3381void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3382 3383/// print - A simple pretty printer of a CFG that outputs to an ostream. 3384void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3385 StmtPrinterHelper Helper(this, LO); 3386 3387 // Print the entry block. 3388 print_block(OS, this, getEntry(), &Helper, true); 3389 3390 // Iterate through the CFGBlocks and print them one by one. 3391 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3392 // Skip the entry block, because we already printed it. 3393 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3394 continue; 3395 3396 print_block(OS, this, **I, &Helper, true); 3397 } 3398 3399 // Print the exit block. 3400 print_block(OS, this, getExit(), &Helper, true); 3401 OS.flush(); 3402} 3403 3404/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3405void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3406 print(llvm::errs(), cfg, LO); 3407} 3408 3409/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3410/// Generally this will only be called from CFG::print. 3411void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3412 const LangOptions &LO) const { 3413 StmtPrinterHelper Helper(cfg, LO); 3414 print_block(OS, cfg, *this, &Helper, true); 3415} 3416 3417/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3418void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3419 const LangOptions &LO) const { 3420 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3421 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3422} 3423 3424Stmt* CFGBlock::getTerminatorCondition() { 3425 Stmt *Terminator = this->Terminator; 3426 if (!Terminator) 3427 return NULL; 3428 3429 Expr* E = NULL; 3430 3431 switch (Terminator->getStmtClass()) { 3432 default: 3433 break; 3434 3435 case Stmt::ForStmtClass: 3436 E = cast<ForStmt>(Terminator)->getCond(); 3437 break; 3438 3439 case Stmt::WhileStmtClass: 3440 E = cast<WhileStmt>(Terminator)->getCond(); 3441 break; 3442 3443 case Stmt::DoStmtClass: 3444 E = cast<DoStmt>(Terminator)->getCond(); 3445 break; 3446 3447 case Stmt::IfStmtClass: 3448 E = cast<IfStmt>(Terminator)->getCond(); 3449 break; 3450 3451 case Stmt::ChooseExprClass: 3452 E = cast<ChooseExpr>(Terminator)->getCond(); 3453 break; 3454 3455 case Stmt::IndirectGotoStmtClass: 3456 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3457 break; 3458 3459 case Stmt::SwitchStmtClass: 3460 E = cast<SwitchStmt>(Terminator)->getCond(); 3461 break; 3462 3463 case Stmt::BinaryConditionalOperatorClass: 3464 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3465 break; 3466 3467 case Stmt::ConditionalOperatorClass: 3468 E = cast<ConditionalOperator>(Terminator)->getCond(); 3469 break; 3470 3471 case Stmt::BinaryOperatorClass: // '&&' and '||' 3472 E = cast<BinaryOperator>(Terminator)->getLHS(); 3473 break; 3474 3475 case Stmt::ObjCForCollectionStmtClass: 3476 return Terminator; 3477 } 3478 3479 return E ? E->IgnoreParens() : NULL; 3480} 3481 3482bool CFGBlock::hasBinaryBranchTerminator() const { 3483 const Stmt *Terminator = this->Terminator; 3484 if (!Terminator) 3485 return false; 3486 3487 Expr* E = NULL; 3488 3489 switch (Terminator->getStmtClass()) { 3490 default: 3491 return false; 3492 3493 case Stmt::ForStmtClass: 3494 case Stmt::WhileStmtClass: 3495 case Stmt::DoStmtClass: 3496 case Stmt::IfStmtClass: 3497 case Stmt::ChooseExprClass: 3498 case Stmt::BinaryConditionalOperatorClass: 3499 case Stmt::ConditionalOperatorClass: 3500 case Stmt::BinaryOperatorClass: 3501 return true; 3502 } 3503 3504 return E ? E->IgnoreParens() : NULL; 3505} 3506 3507 3508//===----------------------------------------------------------------------===// 3509// CFG Graphviz Visualization 3510//===----------------------------------------------------------------------===// 3511 3512 3513#ifndef NDEBUG 3514static StmtPrinterHelper* GraphHelper; 3515#endif 3516 3517void CFG::viewCFG(const LangOptions &LO) const { 3518#ifndef NDEBUG 3519 StmtPrinterHelper H(this, LO); 3520 GraphHelper = &H; 3521 llvm::ViewGraph(this,"CFG"); 3522 GraphHelper = NULL; 3523#endif 3524} 3525 3526namespace llvm { 3527template<> 3528struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3529 3530 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3531 3532 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3533 3534#ifndef NDEBUG 3535 std::string OutSStr; 3536 llvm::raw_string_ostream Out(OutSStr); 3537 print_block(Out,Graph, *Node, GraphHelper, false); 3538 std::string& OutStr = Out.str(); 3539 3540 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3541 3542 // Process string output to make it nicer... 3543 for (unsigned i = 0; i != OutStr.length(); ++i) 3544 if (OutStr[i] == '\n') { // Left justify 3545 OutStr[i] = '\\'; 3546 OutStr.insert(OutStr.begin()+i+1, 'l'); 3547 } 3548 3549 return OutStr; 3550#else 3551 return ""; 3552#endif 3553 } 3554}; 3555} // end namespace llvm 3556