CFG.cpp revision 05adedcb5e199e377e35f576288caf5ceed40136
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39class AddStmtChoice { 40public: 41 enum Kind { NotAlwaysAdd = 0, 42 AlwaysAdd = 1, 43 AsLValueNotAlwaysAdd = 2, 44 AlwaysAddAsLValue = 3 }; 45 46 AddStmtChoice(Kind kind) : k(kind) {} 47 48 bool alwaysAdd() const { return (unsigned)k & 0x1; } 49 bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } 50 51private: 52 Kind k; 53}; 54 55/// LocalScope - Node in tree of local scopes created for C++ implicit 56/// destructor calls generation. It contains list of automatic variables 57/// declared in the scope and link to position in previous scope this scope 58/// began in. 59/// 60/// The process of creating local scopes is as follows: 61/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 62/// - Before processing statements in scope (e.g. CompoundStmt) create 63/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 64/// and set CFGBuilder::ScopePos to the end of new scope, 65/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 66/// at this VarDecl, 67/// - For every normal (without jump) end of scope add to CFGBlock destructors 68/// for objects in the current scope, 69/// - For every jump add to CFGBlock destructors for objects 70/// between CFGBuilder::ScopePos and local scope position saved for jump 71/// target. Thanks to C++ restrictions on goto jumps we can be sure that 72/// jump target position will be on the path to root from CFGBuilder::ScopePos 73/// (adding any variable that doesn't need constructor to be called to 74/// LocalScope can break this assumption), 75/// 76class LocalScope { 77public: 78 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 79 80 /// const_iterator - Iterates local scope backwards and jumps to previous 81 /// scope on reaching the beginning of currently iterated scope. 82 class const_iterator { 83 const LocalScope* Scope; 84 85 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 86 /// Invalid iterator (with null Scope) has VarIter equal to 0. 87 unsigned VarIter; 88 89 public: 90 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 91 /// Incrementing invalid iterator is allowed and will result in invalid 92 /// iterator. 93 const_iterator() 94 : Scope(NULL), VarIter(0) {} 95 96 /// Create valid iterator. In case when S.Prev is an invalid iterator and 97 /// I is equal to 0, this will create invalid iterator. 98 const_iterator(const LocalScope& S, unsigned I) 99 : Scope(&S), VarIter(I) { 100 // Iterator to "end" of scope is not allowed. Handle it by going up 101 // in scopes tree possibly up to invalid iterator in the root. 102 if (VarIter == 0 && Scope) 103 *this = Scope->Prev; 104 } 105 106 VarDecl* const* operator->() const { 107 assert (Scope && "Dereferencing invalid iterator is not allowed"); 108 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 109 return &Scope->Vars[VarIter - 1]; 110 } 111 VarDecl* operator*() const { 112 return *this->operator->(); 113 } 114 115 const_iterator& operator++() { 116 if (!Scope) 117 return *this; 118 119 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 120 --VarIter; 121 if (VarIter == 0) 122 *this = Scope->Prev; 123 return *this; 124 } 125 const_iterator operator++(int) { 126 const_iterator P = *this; 127 ++*this; 128 return P; 129 } 130 131 bool operator==(const const_iterator& rhs) const { 132 return Scope == rhs.Scope && VarIter == rhs.VarIter; 133 } 134 bool operator!=(const const_iterator& rhs) const { 135 return !(*this == rhs); 136 } 137 138 operator bool() const { 139 return *this != const_iterator(); 140 } 141 142 int distance(const_iterator L); 143 }; 144 145 friend class const_iterator; 146 147private: 148 /// Automatic variables in order of declaration. 149 AutomaticVarsTy Vars; 150 /// Iterator to variable in previous scope that was declared just before 151 /// begin of this scope. 152 const_iterator Prev; 153 154public: 155 /// Constructs empty scope linked to previous scope in specified place. 156 LocalScope(const_iterator P) 157 : Vars() 158 , Prev(P) {} 159 160 /// Begin of scope in direction of CFG building (backwards). 161 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 162 163 void addVar(VarDecl* VD) { 164 Vars.push_back(VD); 165 } 166}; 167 168/// distance - Calculates distance from this to L. L must be reachable from this 169/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 170/// number of scopes between this and L. 171int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 172 int D = 0; 173 const_iterator F = *this; 174 while (F.Scope != L.Scope) { 175 assert (F != const_iterator() 176 && "L iterator is not reachable from F iterator."); 177 D += F.VarIter; 178 F = F.Scope->Prev; 179 } 180 D += F.VarIter - L.VarIter; 181 return D; 182} 183 184/// BlockScopePosPair - Structure for specifying position in CFG during its 185/// build process. It consists of CFGBlock that specifies position in CFG graph 186/// and LocalScope::const_iterator that specifies position in LocalScope graph. 187struct BlockScopePosPair { 188 BlockScopePosPair() {} 189 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 190 : Block(B), ScopePos(S) {} 191 192 CFGBlock* Block; 193 LocalScope::const_iterator ScopePos; 194}; 195 196/// CFGBuilder - This class implements CFG construction from an AST. 197/// The builder is stateful: an instance of the builder should be used to only 198/// construct a single CFG. 199/// 200/// Example usage: 201/// 202/// CFGBuilder builder; 203/// CFG* cfg = builder.BuildAST(stmt1); 204/// 205/// CFG construction is done via a recursive walk of an AST. We actually parse 206/// the AST in reverse order so that the successor of a basic block is 207/// constructed prior to its predecessor. This allows us to nicely capture 208/// implicit fall-throughs without extra basic blocks. 209/// 210class CFGBuilder { 211 typedef BlockScopePosPair JumpTarget; 212 typedef BlockScopePosPair JumpSource; 213 214 ASTContext *Context; 215 llvm::OwningPtr<CFG> cfg; 216 217 CFGBlock* Block; 218 CFGBlock* Succ; 219 JumpTarget ContinueJumpTarget; 220 JumpTarget BreakJumpTarget; 221 CFGBlock* SwitchTerminatedBlock; 222 CFGBlock* DefaultCaseBlock; 223 CFGBlock* TryTerminatedBlock; 224 225 // Current position in local scope. 226 LocalScope::const_iterator ScopePos; 227 228 // LabelMap records the mapping from Label expressions to their jump targets. 229 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 230 LabelMapTy LabelMap; 231 232 // A list of blocks that end with a "goto" that must be backpatched to their 233 // resolved targets upon completion of CFG construction. 234 typedef std::vector<JumpSource> BackpatchBlocksTy; 235 BackpatchBlocksTy BackpatchBlocks; 236 237 // A list of labels whose address has been taken (for indirect gotos). 238 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 239 LabelSetTy AddressTakenLabels; 240 241 bool badCFG; 242 CFG::BuildOptions BuildOpts; 243 244public: 245 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 246 Block(NULL), Succ(NULL), 247 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 248 TryTerminatedBlock(NULL), badCFG(false) {} 249 250 // buildCFG - Used by external clients to construct the CFG. 251 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 252 CFG::BuildOptions BO); 253 254private: 255 // Visitors to walk an AST and construct the CFG. 256 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 257 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 258 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 259 CFGBlock *VisitBreakStmt(BreakStmt *B); 260 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 261 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 262 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 263 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 264 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 265 CFGBlock *VisitCaseStmt(CaseStmt *C); 266 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 267 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 268 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 269 CFGBlock *VisitContinueStmt(ContinueStmt *C); 270 CFGBlock *VisitDeclStmt(DeclStmt *DS); 271 CFGBlock *VisitDeclSubExpr(Decl* D); 272 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 273 CFGBlock *VisitDoStmt(DoStmt *D); 274 CFGBlock *VisitForStmt(ForStmt *F); 275 CFGBlock *VisitGotoStmt(GotoStmt* G); 276 CFGBlock *VisitIfStmt(IfStmt *I); 277 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 278 CFGBlock *VisitLabelStmt(LabelStmt *L); 279 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 280 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 281 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 282 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 283 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 284 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 285 CFGBlock *VisitReturnStmt(ReturnStmt* R); 286 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 287 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 288 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 289 CFGBlock *VisitWhileStmt(WhileStmt *W); 290 291 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 292 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 293 CFGBlock *VisitChildren(Stmt* S); 294 295 // NYS == Not Yet Supported 296 CFGBlock* NYS() { 297 badCFG = true; 298 return Block; 299 } 300 301 void autoCreateBlock() { if (!Block) Block = createBlock(); } 302 CFGBlock *createBlock(bool add_successor = true); 303 304 CFGBlock *addStmt(Stmt *S) { 305 return Visit(S, AddStmtChoice::AlwaysAdd); 306 } 307 CFGBlock *addAutomaticObjDtors(LocalScope::const_iterator B, 308 LocalScope::const_iterator E, Stmt* S); 309 310 // Local scopes creation. 311 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 312 313 LocalScope* addLocalScopeForStmt(Stmt* S, LocalScope* Scope = NULL); 314 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 315 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 316 317 void addLocalScopeAndDtors(Stmt* S); 318 319 // Interface to CFGBlock - adding CFGElements. 320 void AppendStmt(CFGBlock *B, Stmt *S, 321 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 322 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 323 } 324 325 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 326 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 327 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 328 LocalScope::const_iterator E, Stmt* S); 329 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 330 LocalScope::const_iterator B, LocalScope::const_iterator E); 331 332 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 333 B->addSuccessor(S, cfg->getBumpVectorContext()); 334 } 335 336 /// TryResult - a class representing a variant over the values 337 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 338 /// and is used by the CFGBuilder to decide if a branch condition 339 /// can be decided up front during CFG construction. 340 class TryResult { 341 int X; 342 public: 343 TryResult(bool b) : X(b ? 1 : 0) {} 344 TryResult() : X(-1) {} 345 346 bool isTrue() const { return X == 1; } 347 bool isFalse() const { return X == 0; } 348 bool isKnown() const { return X >= 0; } 349 void negate() { 350 assert(isKnown()); 351 X ^= 0x1; 352 } 353 }; 354 355 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 356 /// if we can evaluate to a known value, otherwise return -1. 357 TryResult TryEvaluateBool(Expr *S) { 358 if (!BuildOpts.PruneTriviallyFalseEdges) 359 return TryResult(); 360 361 Expr::EvalResult Result; 362 if (!S->isTypeDependent() && !S->isValueDependent() && 363 S->Evaluate(Result, *Context) && Result.Val.isInt()) 364 return Result.Val.getInt().getBoolValue(); 365 366 return TryResult(); 367 } 368}; 369 370// FIXME: Add support for dependent-sized array types in C++? 371// Does it even make sense to build a CFG for an uninstantiated template? 372static VariableArrayType* FindVA(Type* t) { 373 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 374 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 375 if (vat->getSizeExpr()) 376 return vat; 377 378 t = vt->getElementType().getTypePtr(); 379 } 380 381 return 0; 382} 383 384/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 385/// arbitrary statement. Examples include a single expression or a function 386/// body (compound statement). The ownership of the returned CFG is 387/// transferred to the caller. If CFG construction fails, this method returns 388/// NULL. 389CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 390 CFG::BuildOptions BO) { 391 392 Context = C; 393 assert(cfg.get()); 394 if (!Statement) 395 return NULL; 396 397 BuildOpts = BO; 398 if (!C->getLangOptions().CPlusPlus) 399 BuildOpts.AddImplicitDtors = false; 400 401 // Create an empty block that will serve as the exit block for the CFG. Since 402 // this is the first block added to the CFG, it will be implicitly registered 403 // as the exit block. 404 Succ = createBlock(); 405 assert(Succ == &cfg->getExit()); 406 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 407 408 // Visit the statements and create the CFG. 409 CFGBlock *B = addStmt(Statement); 410 411 if (badCFG) 412 return NULL; 413 414 if (B) 415 Succ = B; 416 417 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 418 // FIXME: Add code for base initializers and member initializers. 419 (void)CD; 420 } 421 422 // Backpatch the gotos whose label -> block mappings we didn't know when we 423 // encountered them. 424 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 425 E = BackpatchBlocks.end(); I != E; ++I ) { 426 427 CFGBlock* B = I->Block; 428 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 429 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 430 431 // If there is no target for the goto, then we are looking at an 432 // incomplete AST. Handle this by not registering a successor. 433 if (LI == LabelMap.end()) continue; 434 435 JumpTarget JT = LI->second; 436 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 437 AddSuccessor(B, JT.Block); 438 } 439 440 // Add successors to the Indirect Goto Dispatch block (if we have one). 441 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 442 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 443 E = AddressTakenLabels.end(); I != E; ++I ) { 444 445 // Lookup the target block. 446 LabelMapTy::iterator LI = LabelMap.find(*I); 447 448 // If there is no target block that contains label, then we are looking 449 // at an incomplete AST. Handle this by not registering a successor. 450 if (LI == LabelMap.end()) continue; 451 452 AddSuccessor(B, LI->second.Block); 453 } 454 455 // Create an empty entry block that has no predecessors. 456 cfg->setEntry(createBlock()); 457 458 return cfg.take(); 459} 460 461/// createBlock - Used to lazily create blocks that are connected 462/// to the current (global) succcessor. 463CFGBlock* CFGBuilder::createBlock(bool add_successor) { 464 CFGBlock* B = cfg->createBlock(); 465 if (add_successor && Succ) 466 AddSuccessor(B, Succ); 467 return B; 468} 469 470/// addAutomaticObjDtors - Add to current block automatic objects destructors 471/// for objects in range of local scope positions. Use S as trigger statement 472/// for destructors. 473CFGBlock* CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 474 LocalScope::const_iterator E, Stmt* S) { 475 if (!BuildOpts.AddImplicitDtors) 476 return Block; 477 if (B == E) 478 return Block; 479 480 autoCreateBlock(); 481 appendAutomaticObjDtors(Block, B, E, S); 482 return Block; 483} 484 485/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 486/// way return valid LocalScope object. 487LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 488 if (!Scope) { 489 Scope = cfg->getAllocator().Allocate<LocalScope>(); 490 new (Scope) LocalScope(ScopePos); 491 } 492 return Scope; 493} 494 495/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 496/// that should create implicit scope (e.g. if/else substatements). Will reuse 497/// Scope if not NULL. 498LocalScope* CFGBuilder::addLocalScopeForStmt(Stmt* S, LocalScope* Scope) { 499 if (!BuildOpts.AddImplicitDtors) 500 return Scope; 501 502 // For compound statement we will be creating explicit scope. 503 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 504 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 505 ; BI != BE; ++BI) { 506 Stmt* SI = *BI; 507 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 508 SI = LS->getSubStmt(); 509 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 510 Scope = addLocalScopeForDeclStmt(DS, Scope); 511 } 512 return Scope; 513 } 514 515 // For any other statement scope will be implicit and as such will be 516 // interesting only for DeclStmt. 517 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 518 S = LS->getSubStmt(); 519 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 520 Scope = addLocalScopeForDeclStmt(DS, Scope); 521 return Scope; 522} 523 524/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 525/// reuse Scope if not NULL. 526LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 527 LocalScope* Scope) { 528 if (!BuildOpts.AddImplicitDtors) 529 return Scope; 530 531 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 532 ; DI != DE; ++DI) { 533 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 534 Scope = addLocalScopeForVarDecl(VD, Scope); 535 } 536 return Scope; 537} 538 539/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 540/// create add scope for automatic objects and temporary objects bound to 541/// const reference. Will reuse Scope if not NULL. 542LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 543 LocalScope* Scope) { 544 if (!BuildOpts.AddImplicitDtors) 545 return Scope; 546 547 // Check if variable is local. 548 switch (VD->getStorageClass()) { 549 case SC_None: 550 case SC_Auto: 551 case SC_Register: 552 break; 553 default: return Scope; 554 } 555 556 // Check for const references bound to temporary. Set type to pointee. 557 QualType QT = VD->getType(); 558 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 559 QT = RT->getPointeeType(); 560 if (!QT.isConstQualified()) 561 return Scope; 562 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 563 return Scope; 564 } 565 566 // Check if type is a C++ class with non-trivial destructor. 567 if (const RecordType* RT = QT.getTypePtr()->getAs<RecordType>()) 568 if (const CXXRecordDecl* CD = dyn_cast<CXXRecordDecl>(RT->getDecl())) 569 if (CD->hasTrivialDestructor()) 570 return Scope; 571 572 // Add the variable to scope 573 Scope = createOrReuseLocalScope(Scope); 574 Scope->addVar(VD); 575 ScopePos = Scope->begin(); 576 return Scope; 577} 578 579/// addLocalScopeAndDtors - For given statement add local scope for it and 580/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 581void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 582 if (!BuildOpts.AddImplicitDtors) 583 return; 584 585 LocalScope::const_iterator scopeBeginPos = ScopePos; 586 addLocalScopeForStmt(S, NULL); 587 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 588} 589 590/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 591/// automatic storage duration to CFGBlock's elements vector. Insertion will be 592/// performed in place specified with iterator. 593void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 594 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 595 BumpVectorContext& C = cfg->getBumpVectorContext(); 596 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 597 while (B != E) 598 I = Blk->insertAutomaticObjDtor(I, *B++, S); 599} 600 601/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 602/// automatic storage duration to CFGBlock's elements vector. Elements will be 603/// appended to physical end of the vector which happens to be logical 604/// beginning. 605void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 606 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 607 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 608} 609 610/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 611/// variables with automatic storage duration to CFGBlock's elements vector. 612/// Elements will be prepended to physical beginning of the vector which 613/// happens to be logical end. Use blocks terminator as statement that specifies 614/// destructors call site. 615void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 616 LocalScope::const_iterator B, LocalScope::const_iterator E) { 617 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 618} 619 620/// Visit - Walk the subtree of a statement and add extra 621/// blocks for ternary operators, &&, and ||. We also process "," and 622/// DeclStmts (which may contain nested control-flow). 623CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 624tryAgain: 625 if (!S) { 626 badCFG = true; 627 return 0; 628 } 629 switch (S->getStmtClass()) { 630 default: 631 return VisitStmt(S, asc); 632 633 case Stmt::AddrLabelExprClass: 634 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 635 636 case Stmt::BinaryOperatorClass: 637 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 638 639 case Stmt::BlockExprClass: 640 return VisitBlockExpr(cast<BlockExpr>(S), asc); 641 642 case Stmt::BreakStmtClass: 643 return VisitBreakStmt(cast<BreakStmt>(S)); 644 645 case Stmt::CallExprClass: 646 case Stmt::CXXOperatorCallExprClass: 647 return VisitCallExpr(cast<CallExpr>(S), asc); 648 649 case Stmt::CaseStmtClass: 650 return VisitCaseStmt(cast<CaseStmt>(S)); 651 652 case Stmt::ChooseExprClass: 653 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 654 655 case Stmt::CompoundStmtClass: 656 return VisitCompoundStmt(cast<CompoundStmt>(S)); 657 658 case Stmt::ConditionalOperatorClass: 659 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 660 661 case Stmt::ContinueStmtClass: 662 return VisitContinueStmt(cast<ContinueStmt>(S)); 663 664 case Stmt::CXXCatchStmtClass: 665 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 666 667 case Stmt::CXXExprWithTemporariesClass: { 668 // FIXME: Handle temporaries. For now, just visit the subexpression 669 // so we don't artificially create extra blocks. 670 return Visit(cast<CXXExprWithTemporaries>(S)->getSubExpr(), asc); 671 } 672 673 case Stmt::CXXMemberCallExprClass: 674 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 675 676 case Stmt::CXXThrowExprClass: 677 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 678 679 case Stmt::CXXTryStmtClass: 680 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 681 682 case Stmt::DeclStmtClass: 683 return VisitDeclStmt(cast<DeclStmt>(S)); 684 685 case Stmt::DefaultStmtClass: 686 return VisitDefaultStmt(cast<DefaultStmt>(S)); 687 688 case Stmt::DoStmtClass: 689 return VisitDoStmt(cast<DoStmt>(S)); 690 691 case Stmt::ForStmtClass: 692 return VisitForStmt(cast<ForStmt>(S)); 693 694 case Stmt::GotoStmtClass: 695 return VisitGotoStmt(cast<GotoStmt>(S)); 696 697 case Stmt::IfStmtClass: 698 return VisitIfStmt(cast<IfStmt>(S)); 699 700 case Stmt::IndirectGotoStmtClass: 701 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 702 703 case Stmt::LabelStmtClass: 704 return VisitLabelStmt(cast<LabelStmt>(S)); 705 706 case Stmt::MemberExprClass: 707 return VisitMemberExpr(cast<MemberExpr>(S), asc); 708 709 case Stmt::ObjCAtCatchStmtClass: 710 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 711 712 case Stmt::ObjCAtSynchronizedStmtClass: 713 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 714 715 case Stmt::ObjCAtThrowStmtClass: 716 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 717 718 case Stmt::ObjCAtTryStmtClass: 719 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 720 721 case Stmt::ObjCForCollectionStmtClass: 722 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 723 724 case Stmt::ParenExprClass: 725 S = cast<ParenExpr>(S)->getSubExpr(); 726 goto tryAgain; 727 728 case Stmt::NullStmtClass: 729 return Block; 730 731 case Stmt::ReturnStmtClass: 732 return VisitReturnStmt(cast<ReturnStmt>(S)); 733 734 case Stmt::SizeOfAlignOfExprClass: 735 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 736 737 case Stmt::StmtExprClass: 738 return VisitStmtExpr(cast<StmtExpr>(S), asc); 739 740 case Stmt::SwitchStmtClass: 741 return VisitSwitchStmt(cast<SwitchStmt>(S)); 742 743 case Stmt::WhileStmtClass: 744 return VisitWhileStmt(cast<WhileStmt>(S)); 745 } 746} 747 748CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 749 if (asc.alwaysAdd()) { 750 autoCreateBlock(); 751 AppendStmt(Block, S, asc); 752 } 753 754 return VisitChildren(S); 755} 756 757/// VisitChildren - Visit the children of a Stmt. 758CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 759 CFGBlock *B = Block; 760 for (Stmt::child_iterator I = Terminator->child_begin(), 761 E = Terminator->child_end(); I != E; ++I) { 762 if (*I) B = Visit(*I); 763 } 764 return B; 765} 766 767CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 768 AddStmtChoice asc) { 769 AddressTakenLabels.insert(A->getLabel()); 770 771 if (asc.alwaysAdd()) { 772 autoCreateBlock(); 773 AppendStmt(Block, A, asc); 774 } 775 776 return Block; 777} 778 779CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 780 AddStmtChoice asc) { 781 if (B->isLogicalOp()) { // && or || 782 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 783 AppendStmt(ConfluenceBlock, B, asc); 784 785 if (badCFG) 786 return 0; 787 788 // create the block evaluating the LHS 789 CFGBlock* LHSBlock = createBlock(false); 790 LHSBlock->setTerminator(B); 791 792 // create the block evaluating the RHS 793 Succ = ConfluenceBlock; 794 Block = NULL; 795 CFGBlock* RHSBlock = addStmt(B->getRHS()); 796 797 if (RHSBlock) { 798 if (badCFG) 799 return 0; 800 } 801 else { 802 // Create an empty block for cases where the RHS doesn't require 803 // any explicit statements in the CFG. 804 RHSBlock = createBlock(); 805 } 806 807 // See if this is a known constant. 808 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 809 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 810 KnownVal.negate(); 811 812 // Now link the LHSBlock with RHSBlock. 813 if (B->getOpcode() == BO_LOr) { 814 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 815 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 816 } else { 817 assert(B->getOpcode() == BO_LAnd); 818 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 819 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 820 } 821 822 // Generate the blocks for evaluating the LHS. 823 Block = LHSBlock; 824 return addStmt(B->getLHS()); 825 } 826 else if (B->getOpcode() == BO_Comma) { // , 827 autoCreateBlock(); 828 AppendStmt(Block, B, asc); 829 addStmt(B->getRHS()); 830 return addStmt(B->getLHS()); 831 } 832 else if (B->isAssignmentOp()) { 833 if (asc.alwaysAdd()) { 834 autoCreateBlock(); 835 AppendStmt(Block, B, asc); 836 } 837 838 // If visiting RHS causes us to finish 'Block' and the LHS doesn't 839 // create a new block, then we should return RBlock. Otherwise 840 // we'll incorrectly return NULL. 841 CFGBlock *RBlock = Visit(B->getRHS()); 842 CFGBlock *LBlock = Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 843 return LBlock ? LBlock : RBlock; 844 } 845 846 return VisitStmt(B, asc); 847} 848 849CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 850 if (asc.alwaysAdd()) { 851 autoCreateBlock(); 852 AppendStmt(Block, E, asc); 853 } 854 return Block; 855} 856 857CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 858 // "break" is a control-flow statement. Thus we stop processing the current 859 // block. 860 if (badCFG) 861 return 0; 862 863 // Now create a new block that ends with the break statement. 864 Block = createBlock(false); 865 Block->setTerminator(B); 866 867 // If there is no target for the break, then we are looking at an incomplete 868 // AST. This means that the CFG cannot be constructed. 869 if (BreakJumpTarget.Block) { 870 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 871 AddSuccessor(Block, BreakJumpTarget.Block); 872 } else 873 badCFG = true; 874 875 876 return Block; 877} 878 879static bool CanThrow(Expr *E) { 880 QualType Ty = E->getType(); 881 if (Ty->isFunctionPointerType()) 882 Ty = Ty->getAs<PointerType>()->getPointeeType(); 883 else if (Ty->isBlockPointerType()) 884 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 885 886 const FunctionType *FT = Ty->getAs<FunctionType>(); 887 if (FT) { 888 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 889 if (Proto->hasEmptyExceptionSpec()) 890 return false; 891 } 892 return true; 893} 894 895CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 896 // If this is a call to a no-return function, this stops the block here. 897 bool NoReturn = false; 898 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 899 NoReturn = true; 900 } 901 902 bool AddEHEdge = false; 903 904 // Languages without exceptions are assumed to not throw. 905 if (Context->getLangOptions().Exceptions) { 906 if (BuildOpts.AddEHEdges) 907 AddEHEdge = true; 908 } 909 910 if (FunctionDecl *FD = C->getDirectCallee()) { 911 if (FD->hasAttr<NoReturnAttr>()) 912 NoReturn = true; 913 if (FD->hasAttr<NoThrowAttr>()) 914 AddEHEdge = false; 915 } 916 917 if (!CanThrow(C->getCallee())) 918 AddEHEdge = false; 919 920 if (!NoReturn && !AddEHEdge) { 921 if (asc.asLValue()) 922 return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue); 923 else 924 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 925 } 926 927 if (Block) { 928 Succ = Block; 929 if (badCFG) 930 return 0; 931 } 932 933 Block = createBlock(!NoReturn); 934 AppendStmt(Block, C, asc); 935 936 if (NoReturn) { 937 // Wire this to the exit block directly. 938 AddSuccessor(Block, &cfg->getExit()); 939 } 940 if (AddEHEdge) { 941 // Add exceptional edges. 942 if (TryTerminatedBlock) 943 AddSuccessor(Block, TryTerminatedBlock); 944 else 945 AddSuccessor(Block, &cfg->getExit()); 946 } 947 948 return VisitChildren(C); 949} 950 951CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 952 AddStmtChoice asc) { 953 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 954 AppendStmt(ConfluenceBlock, C, asc); 955 if (badCFG) 956 return 0; 957 958 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 959 : AddStmtChoice::AlwaysAdd; 960 961 Succ = ConfluenceBlock; 962 Block = NULL; 963 CFGBlock* LHSBlock = Visit(C->getLHS(), asc); 964 if (badCFG) 965 return 0; 966 967 Succ = ConfluenceBlock; 968 Block = NULL; 969 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 970 if (badCFG) 971 return 0; 972 973 Block = createBlock(false); 974 // See if this is a known constant. 975 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 976 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 977 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 978 Block->setTerminator(C); 979 return addStmt(C->getCond()); 980} 981 982 983CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 984 addLocalScopeAndDtors(C); 985 CFGBlock* LastBlock = Block; 986 987 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 988 I != E; ++I ) { 989 // If we hit a segment of code just containing ';' (NullStmts), we can 990 // get a null block back. In such cases, just use the LastBlock 991 if (CFGBlock *newBlock = addStmt(*I)) 992 LastBlock = newBlock; 993 994 if (badCFG) 995 return NULL; 996 } 997 998 return LastBlock; 999} 1000 1001CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1002 AddStmtChoice asc) { 1003 // Create the confluence block that will "merge" the results of the ternary 1004 // expression. 1005 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1006 AppendStmt(ConfluenceBlock, C, asc); 1007 if (badCFG) 1008 return 0; 1009 1010 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1011 : AddStmtChoice::AlwaysAdd; 1012 1013 // Create a block for the LHS expression if there is an LHS expression. A 1014 // GCC extension allows LHS to be NULL, causing the condition to be the 1015 // value that is returned instead. 1016 // e.g: x ?: y is shorthand for: x ? x : y; 1017 Succ = ConfluenceBlock; 1018 Block = NULL; 1019 CFGBlock* LHSBlock = NULL; 1020 if (C->getLHS()) { 1021 LHSBlock = Visit(C->getLHS(), asc); 1022 if (badCFG) 1023 return 0; 1024 Block = NULL; 1025 } 1026 1027 // Create the block for the RHS expression. 1028 Succ = ConfluenceBlock; 1029 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1030 if (badCFG) 1031 return 0; 1032 1033 // Create the block that will contain the condition. 1034 Block = createBlock(false); 1035 1036 // See if this is a known constant. 1037 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1038 if (LHSBlock) { 1039 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1040 } else { 1041 if (KnownVal.isFalse()) { 1042 // If we know the condition is false, add NULL as the successor for 1043 // the block containing the condition. In this case, the confluence 1044 // block will have just one predecessor. 1045 AddSuccessor(Block, 0); 1046 assert(ConfluenceBlock->pred_size() == 1); 1047 } else { 1048 // If we have no LHS expression, add the ConfluenceBlock as a direct 1049 // successor for the block containing the condition. Moreover, we need to 1050 // reverse the order of the predecessors in the ConfluenceBlock because 1051 // the RHSBlock will have been added to the succcessors already, and we 1052 // want the first predecessor to the the block containing the expression 1053 // for the case when the ternary expression evaluates to true. 1054 AddSuccessor(Block, ConfluenceBlock); 1055 assert(ConfluenceBlock->pred_size() == 2); 1056 std::reverse(ConfluenceBlock->pred_begin(), 1057 ConfluenceBlock->pred_end()); 1058 } 1059 } 1060 1061 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1062 Block->setTerminator(C); 1063 return addStmt(C->getCond()); 1064} 1065 1066CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1067 autoCreateBlock(); 1068 1069 if (DS->isSingleDecl()) { 1070 AppendStmt(Block, DS); 1071 return VisitDeclSubExpr(DS->getSingleDecl()); 1072 } 1073 1074 CFGBlock *B = 0; 1075 1076 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1077 typedef llvm::SmallVector<Decl*,10> BufTy; 1078 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1079 1080 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1081 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1082 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1083 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1084 1085 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1086 // automatically freed with the CFG. 1087 DeclGroupRef DG(*I); 1088 Decl *D = *I; 1089 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1090 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1091 1092 // Append the fake DeclStmt to block. 1093 AppendStmt(Block, DSNew); 1094 B = VisitDeclSubExpr(D); 1095 } 1096 1097 return B; 1098} 1099 1100/// VisitDeclSubExpr - Utility method to add block-level expressions for 1101/// initializers in Decls. 1102CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 1103 assert(Block); 1104 1105 VarDecl *VD = dyn_cast<VarDecl>(D); 1106 1107 if (!VD) 1108 return Block; 1109 1110 Expr *Init = VD->getInit(); 1111 1112 if (Init) { 1113 AddStmtChoice::Kind k = 1114 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 1115 : AddStmtChoice::NotAlwaysAdd; 1116 Visit(Init, AddStmtChoice(k)); 1117 } 1118 1119 // If the type of VD is a VLA, then we must process its size expressions. 1120 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1121 VA = FindVA(VA->getElementType().getTypePtr())) 1122 Block = addStmt(VA->getSizeExpr()); 1123 1124 // Remove variable from local scope. 1125 if (ScopePos && VD == *ScopePos) 1126 ++ScopePos; 1127 1128 return Block; 1129} 1130 1131CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1132 // We may see an if statement in the middle of a basic block, or it may be the 1133 // first statement we are processing. In either case, we create a new basic 1134 // block. First, we create the blocks for the then...else statements, and 1135 // then we create the block containing the if statement. If we were in the 1136 // middle of a block, we stop processing that block. That block is then the 1137 // implicit successor for the "then" and "else" clauses. 1138 1139 // Save local scope position because in case of condition variable ScopePos 1140 // won't be restored when traversing AST. 1141 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1142 1143 // Create local scope for possible condition variable. 1144 // Store scope position. Add implicit destructor. 1145 if (VarDecl* VD = I->getConditionVariable()) { 1146 LocalScope::const_iterator BeginScopePos = ScopePos; 1147 addLocalScopeForVarDecl(VD); 1148 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1149 } 1150 1151 // The block we were proccessing is now finished. Make it the successor 1152 // block. 1153 if (Block) { 1154 Succ = Block; 1155 if (badCFG) 1156 return 0; 1157 } 1158 1159 // Process the false branch. 1160 CFGBlock* ElseBlock = Succ; 1161 1162 if (Stmt* Else = I->getElse()) { 1163 SaveAndRestore<CFGBlock*> sv(Succ); 1164 1165 // NULL out Block so that the recursive call to Visit will 1166 // create a new basic block. 1167 Block = NULL; 1168 1169 // If branch is not a compound statement create implicit scope 1170 // and add destructors. 1171 if (!isa<CompoundStmt>(Else)) 1172 addLocalScopeAndDtors(Else); 1173 1174 ElseBlock = addStmt(Else); 1175 1176 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1177 ElseBlock = sv.get(); 1178 else if (Block) { 1179 if (badCFG) 1180 return 0; 1181 } 1182 } 1183 1184 // Process the true branch. 1185 CFGBlock* ThenBlock; 1186 { 1187 Stmt* Then = I->getThen(); 1188 assert(Then); 1189 SaveAndRestore<CFGBlock*> sv(Succ); 1190 Block = NULL; 1191 1192 // If branch is not a compound statement create implicit scope 1193 // and add destructors. 1194 if (!isa<CompoundStmt>(Then)) 1195 addLocalScopeAndDtors(Then); 1196 1197 ThenBlock = addStmt(Then); 1198 1199 if (!ThenBlock) { 1200 // We can reach here if the "then" body has all NullStmts. 1201 // Create an empty block so we can distinguish between true and false 1202 // branches in path-sensitive analyses. 1203 ThenBlock = createBlock(false); 1204 AddSuccessor(ThenBlock, sv.get()); 1205 } else if (Block) { 1206 if (badCFG) 1207 return 0; 1208 } 1209 } 1210 1211 // Now create a new block containing the if statement. 1212 Block = createBlock(false); 1213 1214 // Set the terminator of the new block to the If statement. 1215 Block->setTerminator(I); 1216 1217 // See if this is a known constant. 1218 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1219 1220 // Now add the successors. 1221 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1222 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1223 1224 // Add the condition as the last statement in the new block. This may create 1225 // new blocks as the condition may contain control-flow. Any newly created 1226 // blocks will be pointed to be "Block". 1227 Block = addStmt(I->getCond()); 1228 1229 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1230 // and the condition variable initialization to the CFG. 1231 if (VarDecl *VD = I->getConditionVariable()) { 1232 if (Expr *Init = VD->getInit()) { 1233 autoCreateBlock(); 1234 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1235 addStmt(Init); 1236 } 1237 } 1238 1239 return Block; 1240} 1241 1242 1243CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1244 // If we were in the middle of a block we stop processing that block. 1245 // 1246 // NOTE: If a "return" appears in the middle of a block, this means that the 1247 // code afterwards is DEAD (unreachable). We still keep a basic block 1248 // for that code; a simple "mark-and-sweep" from the entry block will be 1249 // able to report such dead blocks. 1250 1251 // Create the new block. 1252 Block = createBlock(false); 1253 1254 // The Exit block is the only successor. 1255 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1256 AddSuccessor(Block, &cfg->getExit()); 1257 1258 // Add the return statement to the block. This may create new blocks if R 1259 // contains control-flow (short-circuit operations). 1260 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1261} 1262 1263CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1264 // Get the block of the labeled statement. Add it to our map. 1265 addStmt(L->getSubStmt()); 1266 CFGBlock* LabelBlock = Block; 1267 1268 if (!LabelBlock) // This can happen when the body is empty, i.e. 1269 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1270 1271 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1272 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1273 1274 // Labels partition blocks, so this is the end of the basic block we were 1275 // processing (L is the block's label). Because this is label (and we have 1276 // already processed the substatement) there is no extra control-flow to worry 1277 // about. 1278 LabelBlock->setLabel(L); 1279 if (badCFG) 1280 return 0; 1281 1282 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1283 Block = NULL; 1284 1285 // This block is now the implicit successor of other blocks. 1286 Succ = LabelBlock; 1287 1288 return LabelBlock; 1289} 1290 1291CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1292 // Goto is a control-flow statement. Thus we stop processing the current 1293 // block and create a new one. 1294 1295 Block = createBlock(false); 1296 Block->setTerminator(G); 1297 1298 // If we already know the mapping to the label block add the successor now. 1299 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1300 1301 if (I == LabelMap.end()) 1302 // We will need to backpatch this block later. 1303 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1304 else { 1305 JumpTarget JT = I->second; 1306 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1307 AddSuccessor(Block, JT.Block); 1308 } 1309 1310 return Block; 1311} 1312 1313CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1314 CFGBlock* LoopSuccessor = NULL; 1315 1316 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1317 1318 // "for" is a control-flow statement. Thus we stop processing the current 1319 // block. 1320 if (Block) { 1321 if (badCFG) 1322 return 0; 1323 LoopSuccessor = Block; 1324 } else 1325 LoopSuccessor = Succ; 1326 1327 // Save the current value for the break targets. 1328 // All breaks should go to the code following the loop. 1329 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1330 BreakJumpTarget = JumpTarget(LoopSuccessor, LoopBeginScopePos); 1331 1332 // Because of short-circuit evaluation, the condition of the loop can span 1333 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1334 // evaluate the condition. 1335 CFGBlock* ExitConditionBlock = createBlock(false); 1336 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1337 1338 // Set the terminator for the "exit" condition block. 1339 ExitConditionBlock->setTerminator(F); 1340 1341 // Now add the actual condition to the condition block. Because the condition 1342 // itself may contain control-flow, new blocks may be created. 1343 if (Stmt* C = F->getCond()) { 1344 Block = ExitConditionBlock; 1345 EntryConditionBlock = addStmt(C); 1346 assert(Block == EntryConditionBlock || 1347 (Block == 0 && EntryConditionBlock == Succ)); 1348 1349 // If this block contains a condition variable, add both the condition 1350 // variable and initializer to the CFG. 1351 if (VarDecl *VD = F->getConditionVariable()) { 1352 if (Expr *Init = VD->getInit()) { 1353 autoCreateBlock(); 1354 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1355 EntryConditionBlock = addStmt(Init); 1356 assert(Block == EntryConditionBlock); 1357 } 1358 } 1359 1360 if (Block) { 1361 if (badCFG) 1362 return 0; 1363 } 1364 } 1365 1366 // The condition block is the implicit successor for the loop body as well as 1367 // any code above the loop. 1368 Succ = EntryConditionBlock; 1369 1370 // See if this is a known constant. 1371 TryResult KnownVal(true); 1372 1373 if (F->getCond()) 1374 KnownVal = TryEvaluateBool(F->getCond()); 1375 1376 // Now create the loop body. 1377 { 1378 assert(F->getBody()); 1379 1380 // Save the current values for Block, Succ, and continue targets. 1381 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1382 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1383 1384 // Create a new block to contain the (bottom) of the loop body. 1385 Block = NULL; 1386 1387 if (Stmt* I = F->getInc()) { 1388 // Generate increment code in its own basic block. This is the target of 1389 // continue statements. 1390 Succ = addStmt(I); 1391 } else { 1392 // No increment code. Create a special, empty, block that is used as the 1393 // target block for "looping back" to the start of the loop. 1394 assert(Succ == EntryConditionBlock); 1395 Succ = createBlock(); 1396 } 1397 1398 // Finish up the increment (or empty) block if it hasn't been already. 1399 if (Block) { 1400 assert(Block == Succ); 1401 if (badCFG) 1402 return 0; 1403 Block = 0; 1404 } 1405 1406 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1407 1408 // The starting block for the loop increment is the block that should 1409 // represent the 'loop target' for looping back to the start of the loop. 1410 ContinueJumpTarget.Block->setLoopTarget(F); 1411 1412 // Now populate the body block, and in the process create new blocks as we 1413 // walk the body of the loop. 1414 CFGBlock* BodyBlock = addStmt(F->getBody()); 1415 1416 if (!BodyBlock) 1417 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1418 else if (badCFG) 1419 return 0; 1420 1421 // This new body block is a successor to our "exit" condition block. 1422 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1423 } 1424 1425 // Link up the condition block with the code that follows the loop. (the 1426 // false branch). 1427 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1428 1429 // If the loop contains initialization, create a new block for those 1430 // statements. This block can also contain statements that precede the loop. 1431 if (Stmt* I = F->getInit()) { 1432 Block = createBlock(); 1433 return addStmt(I); 1434 } else { 1435 // There is no loop initialization. We are thus basically a while loop. 1436 // NULL out Block to force lazy block construction. 1437 Block = NULL; 1438 Succ = EntryConditionBlock; 1439 return EntryConditionBlock; 1440 } 1441} 1442 1443CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1444 if (asc.alwaysAdd()) { 1445 autoCreateBlock(); 1446 AppendStmt(Block, M, asc); 1447 } 1448 return Visit(M->getBase(), 1449 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1450 : AddStmtChoice::AsLValueNotAlwaysAdd); 1451} 1452 1453CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1454 // Objective-C fast enumeration 'for' statements: 1455 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1456 // 1457 // for ( Type newVariable in collection_expression ) { statements } 1458 // 1459 // becomes: 1460 // 1461 // prologue: 1462 // 1. collection_expression 1463 // T. jump to loop_entry 1464 // loop_entry: 1465 // 1. side-effects of element expression 1466 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1467 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1468 // TB: 1469 // statements 1470 // T. jump to loop_entry 1471 // FB: 1472 // what comes after 1473 // 1474 // and 1475 // 1476 // Type existingItem; 1477 // for ( existingItem in expression ) { statements } 1478 // 1479 // becomes: 1480 // 1481 // the same with newVariable replaced with existingItem; the binding works 1482 // the same except that for one ObjCForCollectionStmt::getElement() returns 1483 // a DeclStmt and the other returns a DeclRefExpr. 1484 // 1485 1486 CFGBlock* LoopSuccessor = 0; 1487 1488 if (Block) { 1489 if (badCFG) 1490 return 0; 1491 LoopSuccessor = Block; 1492 Block = 0; 1493 } else 1494 LoopSuccessor = Succ; 1495 1496 // Build the condition blocks. 1497 CFGBlock* ExitConditionBlock = createBlock(false); 1498 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1499 1500 // Set the terminator for the "exit" condition block. 1501 ExitConditionBlock->setTerminator(S); 1502 1503 // The last statement in the block should be the ObjCForCollectionStmt, which 1504 // performs the actual binding to 'element' and determines if there are any 1505 // more items in the collection. 1506 AppendStmt(ExitConditionBlock, S); 1507 Block = ExitConditionBlock; 1508 1509 // Walk the 'element' expression to see if there are any side-effects. We 1510 // generate new blocks as necesary. We DON'T add the statement by default to 1511 // the CFG unless it contains control-flow. 1512 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1513 if (Block) { 1514 if (badCFG) 1515 return 0; 1516 Block = 0; 1517 } 1518 1519 // The condition block is the implicit successor for the loop body as well as 1520 // any code above the loop. 1521 Succ = EntryConditionBlock; 1522 1523 // Now create the true branch. 1524 { 1525 // Save the current values for Succ, continue and break targets. 1526 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1527 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1528 save_break(BreakJumpTarget); 1529 1530 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1531 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1532 1533 CFGBlock* BodyBlock = addStmt(S->getBody()); 1534 1535 if (!BodyBlock) 1536 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1537 else if (Block) { 1538 if (badCFG) 1539 return 0; 1540 } 1541 1542 // This new body block is a successor to our "exit" condition block. 1543 AddSuccessor(ExitConditionBlock, BodyBlock); 1544 } 1545 1546 // Link up the condition block with the code that follows the loop. 1547 // (the false branch). 1548 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1549 1550 // Now create a prologue block to contain the collection expression. 1551 Block = createBlock(); 1552 return addStmt(S->getCollection()); 1553} 1554 1555CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1556 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1557 1558 // Inline the body. 1559 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1560 1561 // The sync body starts its own basic block. This makes it a little easier 1562 // for diagnostic clients. 1563 if (SyncBlock) { 1564 if (badCFG) 1565 return 0; 1566 1567 Block = 0; 1568 Succ = SyncBlock; 1569 } 1570 1571 // Add the @synchronized to the CFG. 1572 autoCreateBlock(); 1573 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1574 1575 // Inline the sync expression. 1576 return addStmt(S->getSynchExpr()); 1577} 1578 1579CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1580 // FIXME 1581 return NYS(); 1582} 1583 1584CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1585 CFGBlock* LoopSuccessor = NULL; 1586 1587 // Save local scope position because in case of condition variable ScopePos 1588 // won't be restored when traversing AST. 1589 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1590 1591 // Create local scope for possible condition variable. 1592 // Store scope position for continue statement. 1593 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1594 if (VarDecl* VD = W->getConditionVariable()) { 1595 addLocalScopeForVarDecl(VD); 1596 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1597 } 1598 1599 // "while" is a control-flow statement. Thus we stop processing the current 1600 // block. 1601 if (Block) { 1602 if (badCFG) 1603 return 0; 1604 LoopSuccessor = Block; 1605 } else 1606 LoopSuccessor = Succ; 1607 1608 // Because of short-circuit evaluation, the condition of the loop can span 1609 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1610 // evaluate the condition. 1611 CFGBlock* ExitConditionBlock = createBlock(false); 1612 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1613 1614 // Set the terminator for the "exit" condition block. 1615 ExitConditionBlock->setTerminator(W); 1616 1617 // Now add the actual condition to the condition block. Because the condition 1618 // itself may contain control-flow, new blocks may be created. Thus we update 1619 // "Succ" after adding the condition. 1620 if (Stmt* C = W->getCond()) { 1621 Block = ExitConditionBlock; 1622 EntryConditionBlock = addStmt(C); 1623 assert(Block == EntryConditionBlock); 1624 1625 // If this block contains a condition variable, add both the condition 1626 // variable and initializer to the CFG. 1627 if (VarDecl *VD = W->getConditionVariable()) { 1628 if (Expr *Init = VD->getInit()) { 1629 autoCreateBlock(); 1630 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1631 EntryConditionBlock = addStmt(Init); 1632 assert(Block == EntryConditionBlock); 1633 } 1634 } 1635 1636 if (Block) { 1637 if (badCFG) 1638 return 0; 1639 } 1640 } 1641 1642 // The condition block is the implicit successor for the loop body as well as 1643 // any code above the loop. 1644 Succ = EntryConditionBlock; 1645 1646 // See if this is a known constant. 1647 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1648 1649 // Process the loop body. 1650 { 1651 assert(W->getBody()); 1652 1653 // Save the current values for Block, Succ, and continue and break targets 1654 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1655 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1656 save_break(BreakJumpTarget); 1657 1658 // Create an empty block to represent the transition block for looping back 1659 // to the head of the loop. 1660 Block = 0; 1661 assert(Succ == EntryConditionBlock); 1662 Succ = createBlock(); 1663 Succ->setLoopTarget(W); 1664 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1665 1666 // All breaks should go to the code following the loop. 1667 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1668 1669 // NULL out Block to force lazy instantiation of blocks for the body. 1670 Block = NULL; 1671 1672 // Loop body should end with destructor of Condition variable (if any). 1673 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1674 1675 // If body is not a compound statement create implicit scope 1676 // and add destructors. 1677 if (!isa<CompoundStmt>(W->getBody())) 1678 addLocalScopeAndDtors(W->getBody()); 1679 1680 // Create the body. The returned block is the entry to the loop body. 1681 CFGBlock* BodyBlock = addStmt(W->getBody()); 1682 1683 if (!BodyBlock) 1684 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1685 else if (Block) { 1686 if (badCFG) 1687 return 0; 1688 } 1689 1690 // Add the loop body entry as a successor to the condition. 1691 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1692 } 1693 1694 // Link up the condition block with the code that follows the loop. (the 1695 // false branch). 1696 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1697 1698 // There can be no more statements in the condition block since we loop back 1699 // to this block. NULL out Block to force lazy creation of another block. 1700 Block = NULL; 1701 1702 // Return the condition block, which is the dominating block for the loop. 1703 Succ = EntryConditionBlock; 1704 return EntryConditionBlock; 1705} 1706 1707 1708CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1709 // FIXME: For now we pretend that @catch and the code it contains does not 1710 // exit. 1711 return Block; 1712} 1713 1714CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1715 // FIXME: This isn't complete. We basically treat @throw like a return 1716 // statement. 1717 1718 // If we were in the middle of a block we stop processing that block. 1719 if (badCFG) 1720 return 0; 1721 1722 // Create the new block. 1723 Block = createBlock(false); 1724 1725 // The Exit block is the only successor. 1726 AddSuccessor(Block, &cfg->getExit()); 1727 1728 // Add the statement to the block. This may create new blocks if S contains 1729 // control-flow (short-circuit operations). 1730 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1731} 1732 1733CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1734 // If we were in the middle of a block we stop processing that block. 1735 if (badCFG) 1736 return 0; 1737 1738 // Create the new block. 1739 Block = createBlock(false); 1740 1741 if (TryTerminatedBlock) 1742 // The current try statement is the only successor. 1743 AddSuccessor(Block, TryTerminatedBlock); 1744 else 1745 // otherwise the Exit block is the only successor. 1746 AddSuccessor(Block, &cfg->getExit()); 1747 1748 // Add the statement to the block. This may create new blocks if S contains 1749 // control-flow (short-circuit operations). 1750 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1751} 1752 1753CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1754 CFGBlock* LoopSuccessor = NULL; 1755 1756 // "do...while" is a control-flow statement. Thus we stop processing the 1757 // current block. 1758 if (Block) { 1759 if (badCFG) 1760 return 0; 1761 LoopSuccessor = Block; 1762 } else 1763 LoopSuccessor = Succ; 1764 1765 // Because of short-circuit evaluation, the condition of the loop can span 1766 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1767 // evaluate the condition. 1768 CFGBlock* ExitConditionBlock = createBlock(false); 1769 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1770 1771 // Set the terminator for the "exit" condition block. 1772 ExitConditionBlock->setTerminator(D); 1773 1774 // Now add the actual condition to the condition block. Because the condition 1775 // itself may contain control-flow, new blocks may be created. 1776 if (Stmt* C = D->getCond()) { 1777 Block = ExitConditionBlock; 1778 EntryConditionBlock = addStmt(C); 1779 if (Block) { 1780 if (badCFG) 1781 return 0; 1782 } 1783 } 1784 1785 // The condition block is the implicit successor for the loop body. 1786 Succ = EntryConditionBlock; 1787 1788 // See if this is a known constant. 1789 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1790 1791 // Process the loop body. 1792 CFGBlock* BodyBlock = NULL; 1793 { 1794 assert(D->getBody()); 1795 1796 // Save the current values for Block, Succ, and continue and break targets 1797 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1798 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1799 save_break(BreakJumpTarget); 1800 1801 // All continues within this loop should go to the condition block 1802 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1803 1804 // All breaks should go to the code following the loop. 1805 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1806 1807 // NULL out Block to force lazy instantiation of blocks for the body. 1808 Block = NULL; 1809 1810 // If body is not a compound statement create implicit scope 1811 // and add destructors. 1812 if (!isa<CompoundStmt>(D->getBody())) 1813 addLocalScopeAndDtors(D->getBody()); 1814 1815 // Create the body. The returned block is the entry to the loop body. 1816 BodyBlock = addStmt(D->getBody()); 1817 1818 if (!BodyBlock) 1819 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1820 else if (Block) { 1821 if (badCFG) 1822 return 0; 1823 } 1824 1825 if (!KnownVal.isFalse()) { 1826 // Add an intermediate block between the BodyBlock and the 1827 // ExitConditionBlock to represent the "loop back" transition. Create an 1828 // empty block to represent the transition block for looping back to the 1829 // head of the loop. 1830 // FIXME: Can we do this more efficiently without adding another block? 1831 Block = NULL; 1832 Succ = BodyBlock; 1833 CFGBlock *LoopBackBlock = createBlock(); 1834 LoopBackBlock->setLoopTarget(D); 1835 1836 // Add the loop body entry as a successor to the condition. 1837 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1838 } 1839 else 1840 AddSuccessor(ExitConditionBlock, NULL); 1841 } 1842 1843 // Link up the condition block with the code that follows the loop. 1844 // (the false branch). 1845 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1846 1847 // There can be no more statements in the body block(s) since we loop back to 1848 // the body. NULL out Block to force lazy creation of another block. 1849 Block = NULL; 1850 1851 // Return the loop body, which is the dominating block for the loop. 1852 Succ = BodyBlock; 1853 return BodyBlock; 1854} 1855 1856CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1857 // "continue" is a control-flow statement. Thus we stop processing the 1858 // current block. 1859 if (badCFG) 1860 return 0; 1861 1862 // Now create a new block that ends with the continue statement. 1863 Block = createBlock(false); 1864 Block->setTerminator(C); 1865 1866 // If there is no target for the continue, then we are looking at an 1867 // incomplete AST. This means the CFG cannot be constructed. 1868 if (ContinueJumpTarget.Block) { 1869 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1870 AddSuccessor(Block, ContinueJumpTarget.Block); 1871 } else 1872 badCFG = true; 1873 1874 return Block; 1875} 1876 1877CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1878 AddStmtChoice asc) { 1879 1880 if (asc.alwaysAdd()) { 1881 autoCreateBlock(); 1882 AppendStmt(Block, E); 1883 } 1884 1885 // VLA types have expressions that must be evaluated. 1886 if (E->isArgumentType()) { 1887 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1888 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1889 addStmt(VA->getSizeExpr()); 1890 } 1891 1892 return Block; 1893} 1894 1895/// VisitStmtExpr - Utility method to handle (nested) statement 1896/// expressions (a GCC extension). 1897CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 1898 if (asc.alwaysAdd()) { 1899 autoCreateBlock(); 1900 AppendStmt(Block, SE); 1901 } 1902 return VisitCompoundStmt(SE->getSubStmt()); 1903} 1904 1905CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1906 // "switch" is a control-flow statement. Thus we stop processing the current 1907 // block. 1908 CFGBlock* SwitchSuccessor = NULL; 1909 1910 if (Block) { 1911 if (badCFG) 1912 return 0; 1913 SwitchSuccessor = Block; 1914 } else SwitchSuccessor = Succ; 1915 1916 // Save the current "switch" context. 1917 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1918 save_default(DefaultCaseBlock); 1919 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1920 1921 // Set the "default" case to be the block after the switch statement. If the 1922 // switch statement contains a "default:", this value will be overwritten with 1923 // the block for that code. 1924 DefaultCaseBlock = SwitchSuccessor; 1925 1926 // Create a new block that will contain the switch statement. 1927 SwitchTerminatedBlock = createBlock(false); 1928 1929 // Now process the switch body. The code after the switch is the implicit 1930 // successor. 1931 Succ = SwitchSuccessor; 1932 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 1933 1934 // When visiting the body, the case statements should automatically get linked 1935 // up to the switch. We also don't keep a pointer to the body, since all 1936 // control-flow from the switch goes to case/default statements. 1937 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 1938 Block = NULL; 1939 addStmt(Terminator->getBody()); 1940 if (Block) { 1941 if (badCFG) 1942 return 0; 1943 } 1944 1945 // If we have no "default:" case, the default transition is to the code 1946 // following the switch body. 1947 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1948 1949 // Add the terminator and condition in the switch block. 1950 SwitchTerminatedBlock->setTerminator(Terminator); 1951 assert(Terminator->getCond() && "switch condition must be non-NULL"); 1952 Block = SwitchTerminatedBlock; 1953 Block = addStmt(Terminator->getCond()); 1954 1955 // Finally, if the SwitchStmt contains a condition variable, add both the 1956 // SwitchStmt and the condition variable initialization to the CFG. 1957 if (VarDecl *VD = Terminator->getConditionVariable()) { 1958 if (Expr *Init = VD->getInit()) { 1959 autoCreateBlock(); 1960 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 1961 addStmt(Init); 1962 } 1963 } 1964 1965 return Block; 1966} 1967 1968CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1969 // CaseStmts are essentially labels, so they are the first statement in a 1970 // block. 1971 CFGBlock *TopBlock = 0, *LastBlock = 0; 1972 1973 if (Stmt *Sub = CS->getSubStmt()) { 1974 // For deeply nested chains of CaseStmts, instead of doing a recursion 1975 // (which can blow out the stack), manually unroll and create blocks 1976 // along the way. 1977 while (isa<CaseStmt>(Sub)) { 1978 CFGBlock *CurrentBlock = createBlock(false); 1979 CurrentBlock->setLabel(CS); 1980 1981 if (TopBlock) 1982 AddSuccessor(LastBlock, CurrentBlock); 1983 else 1984 TopBlock = CurrentBlock; 1985 1986 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 1987 LastBlock = CurrentBlock; 1988 1989 CS = cast<CaseStmt>(Sub); 1990 Sub = CS->getSubStmt(); 1991 } 1992 1993 addStmt(Sub); 1994 } 1995 1996 CFGBlock* CaseBlock = Block; 1997 if (!CaseBlock) 1998 CaseBlock = createBlock(); 1999 2000 // Cases statements partition blocks, so this is the top of the basic block we 2001 // were processing (the "case XXX:" is the label). 2002 CaseBlock->setLabel(CS); 2003 2004 if (badCFG) 2005 return 0; 2006 2007 // Add this block to the list of successors for the block with the switch 2008 // statement. 2009 assert(SwitchTerminatedBlock); 2010 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2011 2012 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2013 Block = NULL; 2014 2015 if (TopBlock) { 2016 AddSuccessor(LastBlock, CaseBlock); 2017 Succ = TopBlock; 2018 } 2019 else { 2020 // This block is now the implicit successor of other blocks. 2021 Succ = CaseBlock; 2022 } 2023 2024 return Succ; 2025} 2026 2027CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2028 if (Terminator->getSubStmt()) 2029 addStmt(Terminator->getSubStmt()); 2030 2031 DefaultCaseBlock = Block; 2032 2033 if (!DefaultCaseBlock) 2034 DefaultCaseBlock = createBlock(); 2035 2036 // Default statements partition blocks, so this is the top of the basic block 2037 // we were processing (the "default:" is the label). 2038 DefaultCaseBlock->setLabel(Terminator); 2039 2040 if (badCFG) 2041 return 0; 2042 2043 // Unlike case statements, we don't add the default block to the successors 2044 // for the switch statement immediately. This is done when we finish 2045 // processing the switch statement. This allows for the default case 2046 // (including a fall-through to the code after the switch statement) to always 2047 // be the last successor of a switch-terminated block. 2048 2049 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2050 Block = NULL; 2051 2052 // This block is now the implicit successor of other blocks. 2053 Succ = DefaultCaseBlock; 2054 2055 return DefaultCaseBlock; 2056} 2057 2058CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2059 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2060 // current block. 2061 CFGBlock* TrySuccessor = NULL; 2062 2063 if (Block) { 2064 if (badCFG) 2065 return 0; 2066 TrySuccessor = Block; 2067 } else TrySuccessor = Succ; 2068 2069 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2070 2071 // Create a new block that will contain the try statement. 2072 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2073 // Add the terminator in the try block. 2074 NewTryTerminatedBlock->setTerminator(Terminator); 2075 2076 bool HasCatchAll = false; 2077 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2078 // The code after the try is the implicit successor. 2079 Succ = TrySuccessor; 2080 CXXCatchStmt *CS = Terminator->getHandler(h); 2081 if (CS->getExceptionDecl() == 0) { 2082 HasCatchAll = true; 2083 } 2084 Block = NULL; 2085 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2086 if (CatchBlock == 0) 2087 return 0; 2088 // Add this block to the list of successors for the block with the try 2089 // statement. 2090 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2091 } 2092 if (!HasCatchAll) { 2093 if (PrevTryTerminatedBlock) 2094 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2095 else 2096 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2097 } 2098 2099 // The code after the try is the implicit successor. 2100 Succ = TrySuccessor; 2101 2102 // Save the current "try" context. 2103 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2104 TryTerminatedBlock = NewTryTerminatedBlock; 2105 2106 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2107 Block = NULL; 2108 Block = addStmt(Terminator->getTryBlock()); 2109 return Block; 2110} 2111 2112CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2113 // CXXCatchStmt are treated like labels, so they are the first statement in a 2114 // block. 2115 2116 if (CS->getHandlerBlock()) 2117 addStmt(CS->getHandlerBlock()); 2118 2119 CFGBlock* CatchBlock = Block; 2120 if (!CatchBlock) 2121 CatchBlock = createBlock(); 2122 2123 CatchBlock->setLabel(CS); 2124 2125 if (badCFG) 2126 return 0; 2127 2128 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2129 Block = NULL; 2130 2131 return CatchBlock; 2132} 2133 2134CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2135 AddStmtChoice asc) { 2136 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2137 : AddStmtChoice::AlwaysAdd; 2138 autoCreateBlock(); 2139 AppendStmt(Block, C, AddStmtChoice(K)); 2140 return VisitChildren(C); 2141} 2142 2143CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2144 // Lazily create the indirect-goto dispatch block if there isn't one already. 2145 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2146 2147 if (!IBlock) { 2148 IBlock = createBlock(false); 2149 cfg->setIndirectGotoBlock(IBlock); 2150 } 2151 2152 // IndirectGoto is a control-flow statement. Thus we stop processing the 2153 // current block and create a new one. 2154 if (badCFG) 2155 return 0; 2156 2157 Block = createBlock(false); 2158 Block->setTerminator(I); 2159 AddSuccessor(Block, IBlock); 2160 return addStmt(I->getTarget()); 2161} 2162 2163} // end anonymous namespace 2164 2165/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2166/// no successors or predecessors. If this is the first block created in the 2167/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2168CFGBlock* CFG::createBlock() { 2169 bool first_block = begin() == end(); 2170 2171 // Create the block. 2172 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2173 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2174 Blocks.push_back(Mem, BlkBVC); 2175 2176 // If this is the first block, set it as the Entry and Exit. 2177 if (first_block) 2178 Entry = Exit = &back(); 2179 2180 // Return the block. 2181 return &back(); 2182} 2183 2184/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2185/// CFG is returned to the caller. 2186CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2187 BuildOptions BO) { 2188 CFGBuilder Builder; 2189 return Builder.buildCFG(D, Statement, C, BO); 2190} 2191 2192//===----------------------------------------------------------------------===// 2193// CFG: Queries for BlkExprs. 2194//===----------------------------------------------------------------------===// 2195 2196namespace { 2197 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2198} 2199 2200static void FindSubExprAssignments(Stmt *S, 2201 llvm::SmallPtrSet<Expr*,50>& Set) { 2202 if (!S) 2203 return; 2204 2205 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2206 Stmt *child = *I; 2207 if (!child) 2208 continue; 2209 2210 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2211 if (B->isAssignmentOp()) Set.insert(B); 2212 2213 FindSubExprAssignments(child, Set); 2214 } 2215} 2216 2217static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2218 BlkExprMapTy* M = new BlkExprMapTy(); 2219 2220 // Look for assignments that are used as subexpressions. These are the only 2221 // assignments that we want to *possibly* register as a block-level 2222 // expression. Basically, if an assignment occurs both in a subexpression and 2223 // at the block-level, it is a block-level expression. 2224 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2225 2226 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2227 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2228 if (CFGStmt S = BI->getAs<CFGStmt>()) 2229 FindSubExprAssignments(S, SubExprAssignments); 2230 2231 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2232 2233 // Iterate over the statements again on identify the Expr* and Stmt* at the 2234 // block-level that are block-level expressions. 2235 2236 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2237 CFGStmt CS = BI->getAs<CFGStmt>(); 2238 if (!CS.isValid()) 2239 continue; 2240 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2241 2242 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2243 // Assignment expressions that are not nested within another 2244 // expression are really "statements" whose value is never used by 2245 // another expression. 2246 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2247 continue; 2248 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2249 // Special handling for statement expressions. The last statement in 2250 // the statement expression is also a block-level expr. 2251 const CompoundStmt* C = Terminator->getSubStmt(); 2252 if (!C->body_empty()) { 2253 unsigned x = M->size(); 2254 (*M)[C->body_back()] = x; 2255 } 2256 } 2257 2258 unsigned x = M->size(); 2259 (*M)[Exp] = x; 2260 } 2261 } 2262 2263 // Look at terminators. The condition is a block-level expression. 2264 2265 Stmt* S = (*I)->getTerminatorCondition(); 2266 2267 if (S && M->find(S) == M->end()) { 2268 unsigned x = M->size(); 2269 (*M)[S] = x; 2270 } 2271 } 2272 2273 return M; 2274} 2275 2276CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2277 assert(S != NULL); 2278 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2279 2280 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2281 BlkExprMapTy::iterator I = M->find(S); 2282 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2283} 2284 2285unsigned CFG::getNumBlkExprs() { 2286 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2287 return M->size(); 2288 else { 2289 // We assume callers interested in the number of BlkExprs will want 2290 // the map constructed if it doesn't already exist. 2291 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2292 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2293 } 2294} 2295 2296//===----------------------------------------------------------------------===// 2297// Filtered walking of the CFG. 2298//===----------------------------------------------------------------------===// 2299 2300bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2301 const CFGBlock *From, const CFGBlock *To) { 2302 2303 if (F.IgnoreDefaultsWithCoveredEnums) { 2304 // If the 'To' has no label or is labeled but the label isn't a 2305 // CaseStmt then filter this edge. 2306 if (const SwitchStmt *S = 2307 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2308 if (S->isAllEnumCasesCovered()) { 2309 const Stmt *L = To->getLabel(); 2310 if (!L || !isa<CaseStmt>(L)) 2311 return true; 2312 } 2313 } 2314 } 2315 2316 return false; 2317} 2318 2319//===----------------------------------------------------------------------===// 2320// Cleanup: CFG dstor. 2321//===----------------------------------------------------------------------===// 2322 2323CFG::~CFG() { 2324 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2325} 2326 2327//===----------------------------------------------------------------------===// 2328// CFG pretty printing 2329//===----------------------------------------------------------------------===// 2330 2331namespace { 2332 2333class StmtPrinterHelper : public PrinterHelper { 2334 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2335 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2336 StmtMapTy StmtMap; 2337 DeclMapTy DeclMap; 2338 signed CurrentBlock; 2339 unsigned CurrentStmt; 2340 const LangOptions &LangOpts; 2341public: 2342 2343 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2344 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2345 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2346 unsigned j = 1; 2347 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2348 BI != BEnd; ++BI, ++j ) { 2349 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2350 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2351 StmtMap[SE] = P; 2352 2353 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2354 DeclMap[DS->getSingleDecl()] = P; 2355 2356 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2357 if (VarDecl* VD = IS->getConditionVariable()) 2358 DeclMap[VD] = P; 2359 2360 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2361 if (VarDecl* VD = FS->getConditionVariable()) 2362 DeclMap[VD] = P; 2363 2364 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2365 if (VarDecl* VD = WS->getConditionVariable()) 2366 DeclMap[VD] = P; 2367 2368 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2369 if (VarDecl* VD = SS->getConditionVariable()) 2370 DeclMap[VD] = P; 2371 2372 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2373 if (VarDecl* VD = CS->getExceptionDecl()) 2374 DeclMap[VD] = P; 2375 } 2376 } 2377 } 2378 } 2379 } 2380 2381 virtual ~StmtPrinterHelper() {} 2382 2383 const LangOptions &getLangOpts() const { return LangOpts; } 2384 void setBlockID(signed i) { CurrentBlock = i; } 2385 void setStmtID(unsigned i) { CurrentStmt = i; } 2386 2387 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2388 StmtMapTy::iterator I = StmtMap.find(S); 2389 2390 if (I == StmtMap.end()) 2391 return false; 2392 2393 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2394 && I->second.second == CurrentStmt) { 2395 return false; 2396 } 2397 2398 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2399 return true; 2400 } 2401 2402 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2403 DeclMapTy::iterator I = DeclMap.find(D); 2404 2405 if (I == DeclMap.end()) 2406 return false; 2407 2408 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2409 && I->second.second == CurrentStmt) { 2410 return false; 2411 } 2412 2413 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2414 return true; 2415 } 2416}; 2417} // end anonymous namespace 2418 2419 2420namespace { 2421class CFGBlockTerminatorPrint 2422 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2423 2424 llvm::raw_ostream& OS; 2425 StmtPrinterHelper* Helper; 2426 PrintingPolicy Policy; 2427public: 2428 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2429 const PrintingPolicy &Policy) 2430 : OS(os), Helper(helper), Policy(Policy) {} 2431 2432 void VisitIfStmt(IfStmt* I) { 2433 OS << "if "; 2434 I->getCond()->printPretty(OS,Helper,Policy); 2435 } 2436 2437 // Default case. 2438 void VisitStmt(Stmt* Terminator) { 2439 Terminator->printPretty(OS, Helper, Policy); 2440 } 2441 2442 void VisitForStmt(ForStmt* F) { 2443 OS << "for (" ; 2444 if (F->getInit()) 2445 OS << "..."; 2446 OS << "; "; 2447 if (Stmt* C = F->getCond()) 2448 C->printPretty(OS, Helper, Policy); 2449 OS << "; "; 2450 if (F->getInc()) 2451 OS << "..."; 2452 OS << ")"; 2453 } 2454 2455 void VisitWhileStmt(WhileStmt* W) { 2456 OS << "while " ; 2457 if (Stmt* C = W->getCond()) 2458 C->printPretty(OS, Helper, Policy); 2459 } 2460 2461 void VisitDoStmt(DoStmt* D) { 2462 OS << "do ... while "; 2463 if (Stmt* C = D->getCond()) 2464 C->printPretty(OS, Helper, Policy); 2465 } 2466 2467 void VisitSwitchStmt(SwitchStmt* Terminator) { 2468 OS << "switch "; 2469 Terminator->getCond()->printPretty(OS, Helper, Policy); 2470 } 2471 2472 void VisitCXXTryStmt(CXXTryStmt* CS) { 2473 OS << "try ..."; 2474 } 2475 2476 void VisitConditionalOperator(ConditionalOperator* C) { 2477 C->getCond()->printPretty(OS, Helper, Policy); 2478 OS << " ? ... : ..."; 2479 } 2480 2481 void VisitChooseExpr(ChooseExpr* C) { 2482 OS << "__builtin_choose_expr( "; 2483 C->getCond()->printPretty(OS, Helper, Policy); 2484 OS << " )"; 2485 } 2486 2487 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2488 OS << "goto *"; 2489 I->getTarget()->printPretty(OS, Helper, Policy); 2490 } 2491 2492 void VisitBinaryOperator(BinaryOperator* B) { 2493 if (!B->isLogicalOp()) { 2494 VisitExpr(B); 2495 return; 2496 } 2497 2498 B->getLHS()->printPretty(OS, Helper, Policy); 2499 2500 switch (B->getOpcode()) { 2501 case BO_LOr: 2502 OS << " || ..."; 2503 return; 2504 case BO_LAnd: 2505 OS << " && ..."; 2506 return; 2507 default: 2508 assert(false && "Invalid logical operator."); 2509 } 2510 } 2511 2512 void VisitExpr(Expr* E) { 2513 E->printPretty(OS, Helper, Policy); 2514 } 2515}; 2516} // end anonymous namespace 2517 2518static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2519 const CFGElement &E) { 2520 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2521 Stmt *S = CS; 2522 2523 if (Helper) { 2524 2525 // special printing for statement-expressions. 2526 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2527 CompoundStmt* Sub = SE->getSubStmt(); 2528 2529 if (Sub->child_begin() != Sub->child_end()) { 2530 OS << "({ ... ; "; 2531 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2532 OS << " })\n"; 2533 return; 2534 } 2535 } 2536 // special printing for comma expressions. 2537 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2538 if (B->getOpcode() == BO_Comma) { 2539 OS << "... , "; 2540 Helper->handledStmt(B->getRHS(),OS); 2541 OS << '\n'; 2542 return; 2543 } 2544 } 2545 } 2546 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2547 2548 if (isa<CXXOperatorCallExpr>(S)) { 2549 OS << " (OperatorCall)"; 2550 } 2551 else if (isa<CXXBindTemporaryExpr>(S)) { 2552 OS << " (BindTemporary)"; 2553 } 2554 2555 // Expressions need a newline. 2556 if (isa<Expr>(S)) 2557 OS << '\n'; 2558 2559 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2560 CXXBaseOrMemberInitializer* I = IE; 2561 if (I->isBaseInitializer()) 2562 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2563 else OS << I->getMember()->getName(); 2564 2565 OS << "("; 2566 if (Expr* IE = I->getInit()) 2567 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2568 OS << ")"; 2569 2570 if (I->isBaseInitializer()) 2571 OS << " (Base initializer)\n"; 2572 else OS << " (Member initializer)\n"; 2573 2574 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2575 VarDecl* VD = DE.getVarDecl(); 2576 Helper->handleDecl(VD, OS); 2577 2578 Type* T = VD->getType().getTypePtr(); 2579 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2580 T = RT->getPointeeType().getTypePtr(); 2581 2582 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2583 OS << " (Implicit destructor)\n"; 2584 } 2585 } 2586 2587static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2588 const CFGBlock& B, 2589 StmtPrinterHelper* Helper, bool print_edges) { 2590 2591 if (Helper) Helper->setBlockID(B.getBlockID()); 2592 2593 // Print the header. 2594 OS << "\n [ B" << B.getBlockID(); 2595 2596 if (&B == &cfg->getEntry()) 2597 OS << " (ENTRY) ]\n"; 2598 else if (&B == &cfg->getExit()) 2599 OS << " (EXIT) ]\n"; 2600 else if (&B == cfg->getIndirectGotoBlock()) 2601 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2602 else 2603 OS << " ]\n"; 2604 2605 // Print the label of this block. 2606 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2607 2608 if (print_edges) 2609 OS << " "; 2610 2611 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2612 OS << L->getName(); 2613 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2614 OS << "case "; 2615 C->getLHS()->printPretty(OS, Helper, 2616 PrintingPolicy(Helper->getLangOpts())); 2617 if (C->getRHS()) { 2618 OS << " ... "; 2619 C->getRHS()->printPretty(OS, Helper, 2620 PrintingPolicy(Helper->getLangOpts())); 2621 } 2622 } else if (isa<DefaultStmt>(Label)) 2623 OS << "default"; 2624 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2625 OS << "catch ("; 2626 if (CS->getExceptionDecl()) 2627 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2628 0); 2629 else 2630 OS << "..."; 2631 OS << ")"; 2632 2633 } else 2634 assert(false && "Invalid label statement in CFGBlock."); 2635 2636 OS << ":\n"; 2637 } 2638 2639 // Iterate through the statements in the block and print them. 2640 unsigned j = 1; 2641 2642 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2643 I != E ; ++I, ++j ) { 2644 2645 // Print the statement # in the basic block and the statement itself. 2646 if (print_edges) 2647 OS << " "; 2648 2649 OS << llvm::format("%3d", j) << ": "; 2650 2651 if (Helper) 2652 Helper->setStmtID(j); 2653 2654 print_elem(OS,Helper,*I); 2655 } 2656 2657 // Print the terminator of this block. 2658 if (B.getTerminator()) { 2659 if (print_edges) 2660 OS << " "; 2661 2662 OS << " T: "; 2663 2664 if (Helper) Helper->setBlockID(-1); 2665 2666 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2667 PrintingPolicy(Helper->getLangOpts())); 2668 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2669 OS << '\n'; 2670 } 2671 2672 if (print_edges) { 2673 // Print the predecessors of this block. 2674 OS << " Predecessors (" << B.pred_size() << "):"; 2675 unsigned i = 0; 2676 2677 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2678 I != E; ++I, ++i) { 2679 2680 if (i == 8 || (i-8) == 0) 2681 OS << "\n "; 2682 2683 OS << " B" << (*I)->getBlockID(); 2684 } 2685 2686 OS << '\n'; 2687 2688 // Print the successors of this block. 2689 OS << " Successors (" << B.succ_size() << "):"; 2690 i = 0; 2691 2692 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2693 I != E; ++I, ++i) { 2694 2695 if (i == 8 || (i-8) % 10 == 0) 2696 OS << "\n "; 2697 2698 if (*I) 2699 OS << " B" << (*I)->getBlockID(); 2700 else 2701 OS << " NULL"; 2702 } 2703 2704 OS << '\n'; 2705 } 2706} 2707 2708 2709/// dump - A simple pretty printer of a CFG that outputs to stderr. 2710void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2711 2712/// print - A simple pretty printer of a CFG that outputs to an ostream. 2713void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2714 StmtPrinterHelper Helper(this, LO); 2715 2716 // Print the entry block. 2717 print_block(OS, this, getEntry(), &Helper, true); 2718 2719 // Iterate through the CFGBlocks and print them one by one. 2720 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2721 // Skip the entry block, because we already printed it. 2722 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2723 continue; 2724 2725 print_block(OS, this, **I, &Helper, true); 2726 } 2727 2728 // Print the exit block. 2729 print_block(OS, this, getExit(), &Helper, true); 2730 OS.flush(); 2731} 2732 2733/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2734void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2735 print(llvm::errs(), cfg, LO); 2736} 2737 2738/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2739/// Generally this will only be called from CFG::print. 2740void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2741 const LangOptions &LO) const { 2742 StmtPrinterHelper Helper(cfg, LO); 2743 print_block(OS, cfg, *this, &Helper, true); 2744} 2745 2746/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2747void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2748 const LangOptions &LO) const { 2749 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2750 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2751} 2752 2753Stmt* CFGBlock::getTerminatorCondition() { 2754 2755 if (!Terminator) 2756 return NULL; 2757 2758 Expr* E = NULL; 2759 2760 switch (Terminator->getStmtClass()) { 2761 default: 2762 break; 2763 2764 case Stmt::ForStmtClass: 2765 E = cast<ForStmt>(Terminator)->getCond(); 2766 break; 2767 2768 case Stmt::WhileStmtClass: 2769 E = cast<WhileStmt>(Terminator)->getCond(); 2770 break; 2771 2772 case Stmt::DoStmtClass: 2773 E = cast<DoStmt>(Terminator)->getCond(); 2774 break; 2775 2776 case Stmt::IfStmtClass: 2777 E = cast<IfStmt>(Terminator)->getCond(); 2778 break; 2779 2780 case Stmt::ChooseExprClass: 2781 E = cast<ChooseExpr>(Terminator)->getCond(); 2782 break; 2783 2784 case Stmt::IndirectGotoStmtClass: 2785 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2786 break; 2787 2788 case Stmt::SwitchStmtClass: 2789 E = cast<SwitchStmt>(Terminator)->getCond(); 2790 break; 2791 2792 case Stmt::ConditionalOperatorClass: 2793 E = cast<ConditionalOperator>(Terminator)->getCond(); 2794 break; 2795 2796 case Stmt::BinaryOperatorClass: // '&&' and '||' 2797 E = cast<BinaryOperator>(Terminator)->getLHS(); 2798 break; 2799 2800 case Stmt::ObjCForCollectionStmtClass: 2801 return Terminator; 2802 } 2803 2804 return E ? E->IgnoreParens() : NULL; 2805} 2806 2807bool CFGBlock::hasBinaryBranchTerminator() const { 2808 2809 if (!Terminator) 2810 return false; 2811 2812 Expr* E = NULL; 2813 2814 switch (Terminator->getStmtClass()) { 2815 default: 2816 return false; 2817 2818 case Stmt::ForStmtClass: 2819 case Stmt::WhileStmtClass: 2820 case Stmt::DoStmtClass: 2821 case Stmt::IfStmtClass: 2822 case Stmt::ChooseExprClass: 2823 case Stmt::ConditionalOperatorClass: 2824 case Stmt::BinaryOperatorClass: 2825 return true; 2826 } 2827 2828 return E ? E->IgnoreParens() : NULL; 2829} 2830 2831 2832//===----------------------------------------------------------------------===// 2833// CFG Graphviz Visualization 2834//===----------------------------------------------------------------------===// 2835 2836 2837#ifndef NDEBUG 2838static StmtPrinterHelper* GraphHelper; 2839#endif 2840 2841void CFG::viewCFG(const LangOptions &LO) const { 2842#ifndef NDEBUG 2843 StmtPrinterHelper H(this, LO); 2844 GraphHelper = &H; 2845 llvm::ViewGraph(this,"CFG"); 2846 GraphHelper = NULL; 2847#endif 2848} 2849 2850namespace llvm { 2851template<> 2852struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2853 2854 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2855 2856 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 2857 2858#ifndef NDEBUG 2859 std::string OutSStr; 2860 llvm::raw_string_ostream Out(OutSStr); 2861 print_block(Out,Graph, *Node, GraphHelper, false); 2862 std::string& OutStr = Out.str(); 2863 2864 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2865 2866 // Process string output to make it nicer... 2867 for (unsigned i = 0; i != OutStr.length(); ++i) 2868 if (OutStr[i] == '\n') { // Left justify 2869 OutStr[i] = '\\'; 2870 OutStr.insert(OutStr.begin()+i+1, 'l'); 2871 } 2872 2873 return OutStr; 2874#else 2875 return ""; 2876#endif 2877 } 2878}; 2879} // end namespace llvm 2880