CFG.cpp revision 02acdfaeb3f3805b65e4707e5dff096209adb367
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 void addLocalScopeForStmt(Stmt* S); 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). 497void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 498 if (!BuildOpts.AddImplicitDtors) 499 return; 500 501 LocalScope *Scope = 0; 502 503 // For compound statement we will be creating explicit scope. 504 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 505 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 506 ; BI != BE; ++BI) { 507 Stmt* SI = *BI; 508 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 509 SI = LS->getSubStmt(); 510 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 511 Scope = addLocalScopeForDeclStmt(DS, Scope); 512 } 513 return; 514 } 515 516 // For any other statement scope will be implicit and as such will be 517 // interesting only for DeclStmt. 518 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 519 S = LS->getSubStmt(); 520 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 521 addLocalScopeForDeclStmt(DS, 0); 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 // Add the variable to scope 571 Scope = createOrReuseLocalScope(Scope); 572 Scope->addVar(VD); 573 ScopePos = Scope->begin(); 574 } 575 return Scope; 576} 577 578/// addLocalScopeAndDtors - For given statement add local scope for it and 579/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 580void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 581 if (!BuildOpts.AddImplicitDtors) 582 return; 583 584 LocalScope::const_iterator scopeBeginPos = ScopePos; 585 addLocalScopeForStmt(S); 586 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 587} 588 589/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 590/// automatic storage duration to CFGBlock's elements vector. Insertion will be 591/// performed in place specified with iterator. 592void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 593 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 594 BumpVectorContext& C = cfg->getBumpVectorContext(); 595 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 596 while (B != E) 597 I = Blk->insertAutomaticObjDtor(I, *B++, S); 598} 599 600/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 601/// automatic storage duration to CFGBlock's elements vector. Elements will be 602/// appended to physical end of the vector which happens to be logical 603/// beginning. 604void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 605 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 606 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 607} 608 609/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 610/// variables with automatic storage duration to CFGBlock's elements vector. 611/// Elements will be prepended to physical beginning of the vector which 612/// happens to be logical end. Use blocks terminator as statement that specifies 613/// destructors call site. 614void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 615 LocalScope::const_iterator B, LocalScope::const_iterator E) { 616 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 617} 618 619/// Visit - Walk the subtree of a statement and add extra 620/// blocks for ternary operators, &&, and ||. We also process "," and 621/// DeclStmts (which may contain nested control-flow). 622CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 623tryAgain: 624 if (!S) { 625 badCFG = true; 626 return 0; 627 } 628 switch (S->getStmtClass()) { 629 default: 630 return VisitStmt(S, asc); 631 632 case Stmt::AddrLabelExprClass: 633 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 634 635 case Stmt::BinaryOperatorClass: 636 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 637 638 case Stmt::BlockExprClass: 639 return VisitBlockExpr(cast<BlockExpr>(S), asc); 640 641 case Stmt::BreakStmtClass: 642 return VisitBreakStmt(cast<BreakStmt>(S)); 643 644 case Stmt::CallExprClass: 645 case Stmt::CXXOperatorCallExprClass: 646 return VisitCallExpr(cast<CallExpr>(S), asc); 647 648 case Stmt::CaseStmtClass: 649 return VisitCaseStmt(cast<CaseStmt>(S)); 650 651 case Stmt::ChooseExprClass: 652 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 653 654 case Stmt::CompoundStmtClass: 655 return VisitCompoundStmt(cast<CompoundStmt>(S)); 656 657 case Stmt::ConditionalOperatorClass: 658 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 659 660 case Stmt::ContinueStmtClass: 661 return VisitContinueStmt(cast<ContinueStmt>(S)); 662 663 case Stmt::CXXCatchStmtClass: 664 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 665 666 case Stmt::CXXExprWithTemporariesClass: { 667 // FIXME: Handle temporaries. For now, just visit the subexpression 668 // so we don't artificially create extra blocks. 669 return Visit(cast<CXXExprWithTemporaries>(S)->getSubExpr(), asc); 670 } 671 672 case Stmt::CXXMemberCallExprClass: 673 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 674 675 case Stmt::CXXThrowExprClass: 676 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 677 678 case Stmt::CXXTryStmtClass: 679 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 680 681 case Stmt::DeclStmtClass: 682 return VisitDeclStmt(cast<DeclStmt>(S)); 683 684 case Stmt::DefaultStmtClass: 685 return VisitDefaultStmt(cast<DefaultStmt>(S)); 686 687 case Stmt::DoStmtClass: 688 return VisitDoStmt(cast<DoStmt>(S)); 689 690 case Stmt::ForStmtClass: 691 return VisitForStmt(cast<ForStmt>(S)); 692 693 case Stmt::GotoStmtClass: 694 return VisitGotoStmt(cast<GotoStmt>(S)); 695 696 case Stmt::IfStmtClass: 697 return VisitIfStmt(cast<IfStmt>(S)); 698 699 case Stmt::IndirectGotoStmtClass: 700 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 701 702 case Stmt::LabelStmtClass: 703 return VisitLabelStmt(cast<LabelStmt>(S)); 704 705 case Stmt::MemberExprClass: 706 return VisitMemberExpr(cast<MemberExpr>(S), asc); 707 708 case Stmt::ObjCAtCatchStmtClass: 709 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 710 711 case Stmt::ObjCAtSynchronizedStmtClass: 712 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 713 714 case Stmt::ObjCAtThrowStmtClass: 715 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 716 717 case Stmt::ObjCAtTryStmtClass: 718 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 719 720 case Stmt::ObjCForCollectionStmtClass: 721 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 722 723 case Stmt::ParenExprClass: 724 S = cast<ParenExpr>(S)->getSubExpr(); 725 goto tryAgain; 726 727 case Stmt::NullStmtClass: 728 return Block; 729 730 case Stmt::ReturnStmtClass: 731 return VisitReturnStmt(cast<ReturnStmt>(S)); 732 733 case Stmt::SizeOfAlignOfExprClass: 734 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 735 736 case Stmt::StmtExprClass: 737 return VisitStmtExpr(cast<StmtExpr>(S), asc); 738 739 case Stmt::SwitchStmtClass: 740 return VisitSwitchStmt(cast<SwitchStmt>(S)); 741 742 case Stmt::WhileStmtClass: 743 return VisitWhileStmt(cast<WhileStmt>(S)); 744 } 745} 746 747CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 748 if (asc.alwaysAdd()) { 749 autoCreateBlock(); 750 AppendStmt(Block, S, asc); 751 } 752 753 return VisitChildren(S); 754} 755 756/// VisitChildren - Visit the children of a Stmt. 757CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 758 CFGBlock *B = Block; 759 for (Stmt::child_iterator I = Terminator->child_begin(), 760 E = Terminator->child_end(); I != E; ++I) { 761 if (*I) B = Visit(*I); 762 } 763 return B; 764} 765 766CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 767 AddStmtChoice asc) { 768 AddressTakenLabels.insert(A->getLabel()); 769 770 if (asc.alwaysAdd()) { 771 autoCreateBlock(); 772 AppendStmt(Block, A, asc); 773 } 774 775 return Block; 776} 777 778CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 779 AddStmtChoice asc) { 780 if (B->isLogicalOp()) { // && or || 781 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 782 AppendStmt(ConfluenceBlock, B, asc); 783 784 if (badCFG) 785 return 0; 786 787 // create the block evaluating the LHS 788 CFGBlock* LHSBlock = createBlock(false); 789 LHSBlock->setTerminator(B); 790 791 // create the block evaluating the RHS 792 Succ = ConfluenceBlock; 793 Block = NULL; 794 CFGBlock* RHSBlock = addStmt(B->getRHS()); 795 796 if (RHSBlock) { 797 if (badCFG) 798 return 0; 799 } 800 else { 801 // Create an empty block for cases where the RHS doesn't require 802 // any explicit statements in the CFG. 803 RHSBlock = createBlock(); 804 } 805 806 // See if this is a known constant. 807 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 808 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 809 KnownVal.negate(); 810 811 // Now link the LHSBlock with RHSBlock. 812 if (B->getOpcode() == BO_LOr) { 813 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 814 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 815 } else { 816 assert(B->getOpcode() == BO_LAnd); 817 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 818 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 819 } 820 821 // Generate the blocks for evaluating the LHS. 822 Block = LHSBlock; 823 return addStmt(B->getLHS()); 824 } 825 else if (B->getOpcode() == BO_Comma) { // , 826 autoCreateBlock(); 827 AppendStmt(Block, B, asc); 828 addStmt(B->getRHS()); 829 return addStmt(B->getLHS()); 830 } 831 else if (B->isAssignmentOp()) { 832 if (asc.alwaysAdd()) { 833 autoCreateBlock(); 834 AppendStmt(Block, B, asc); 835 } 836 837 // If visiting RHS causes us to finish 'Block' and the LHS doesn't 838 // create a new block, then we should return RBlock. Otherwise 839 // we'll incorrectly return NULL. 840 CFGBlock *RBlock = Visit(B->getRHS()); 841 CFGBlock *LBlock = Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 842 return LBlock ? LBlock : RBlock; 843 } 844 845 return VisitStmt(B, asc); 846} 847 848CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 849 if (asc.alwaysAdd()) { 850 autoCreateBlock(); 851 AppendStmt(Block, E, asc); 852 } 853 return Block; 854} 855 856CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 857 // "break" is a control-flow statement. Thus we stop processing the current 858 // block. 859 if (badCFG) 860 return 0; 861 862 // Now create a new block that ends with the break statement. 863 Block = createBlock(false); 864 Block->setTerminator(B); 865 866 // If there is no target for the break, then we are looking at an incomplete 867 // AST. This means that the CFG cannot be constructed. 868 if (BreakJumpTarget.Block) { 869 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 870 AddSuccessor(Block, BreakJumpTarget.Block); 871 } else 872 badCFG = true; 873 874 875 return Block; 876} 877 878static bool CanThrow(Expr *E) { 879 QualType Ty = E->getType(); 880 if (Ty->isFunctionPointerType()) 881 Ty = Ty->getAs<PointerType>()->getPointeeType(); 882 else if (Ty->isBlockPointerType()) 883 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 884 885 const FunctionType *FT = Ty->getAs<FunctionType>(); 886 if (FT) { 887 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 888 if (Proto->hasEmptyExceptionSpec()) 889 return false; 890 } 891 return true; 892} 893 894CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 895 // If this is a call to a no-return function, this stops the block here. 896 bool NoReturn = false; 897 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 898 NoReturn = true; 899 } 900 901 bool AddEHEdge = false; 902 903 // Languages without exceptions are assumed to not throw. 904 if (Context->getLangOptions().Exceptions) { 905 if (BuildOpts.AddEHEdges) 906 AddEHEdge = true; 907 } 908 909 if (FunctionDecl *FD = C->getDirectCallee()) { 910 if (FD->hasAttr<NoReturnAttr>()) 911 NoReturn = true; 912 if (FD->hasAttr<NoThrowAttr>()) 913 AddEHEdge = false; 914 } 915 916 if (!CanThrow(C->getCallee())) 917 AddEHEdge = false; 918 919 if (!NoReturn && !AddEHEdge) { 920 if (asc.asLValue()) 921 return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue); 922 else 923 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 924 } 925 926 if (Block) { 927 Succ = Block; 928 if (badCFG) 929 return 0; 930 } 931 932 Block = createBlock(!NoReturn); 933 AppendStmt(Block, C, asc); 934 935 if (NoReturn) { 936 // Wire this to the exit block directly. 937 AddSuccessor(Block, &cfg->getExit()); 938 } 939 if (AddEHEdge) { 940 // Add exceptional edges. 941 if (TryTerminatedBlock) 942 AddSuccessor(Block, TryTerminatedBlock); 943 else 944 AddSuccessor(Block, &cfg->getExit()); 945 } 946 947 return VisitChildren(C); 948} 949 950CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 951 AddStmtChoice asc) { 952 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 953 AppendStmt(ConfluenceBlock, C, asc); 954 if (badCFG) 955 return 0; 956 957 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 958 : AddStmtChoice::AlwaysAdd; 959 960 Succ = ConfluenceBlock; 961 Block = NULL; 962 CFGBlock* LHSBlock = Visit(C->getLHS(), asc); 963 if (badCFG) 964 return 0; 965 966 Succ = ConfluenceBlock; 967 Block = NULL; 968 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 969 if (badCFG) 970 return 0; 971 972 Block = createBlock(false); 973 // See if this is a known constant. 974 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 975 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 976 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 977 Block->setTerminator(C); 978 return addStmt(C->getCond()); 979} 980 981 982CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 983 addLocalScopeAndDtors(C); 984 CFGBlock* LastBlock = Block; 985 986 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 987 I != E; ++I ) { 988 // If we hit a segment of code just containing ';' (NullStmts), we can 989 // get a null block back. In such cases, just use the LastBlock 990 if (CFGBlock *newBlock = addStmt(*I)) 991 LastBlock = newBlock; 992 993 if (badCFG) 994 return NULL; 995 } 996 997 return LastBlock; 998} 999 1000CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1001 AddStmtChoice asc) { 1002 // Create the confluence block that will "merge" the results of the ternary 1003 // expression. 1004 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1005 AppendStmt(ConfluenceBlock, C, asc); 1006 if (badCFG) 1007 return 0; 1008 1009 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1010 : AddStmtChoice::AlwaysAdd; 1011 1012 // Create a block for the LHS expression if there is an LHS expression. A 1013 // GCC extension allows LHS to be NULL, causing the condition to be the 1014 // value that is returned instead. 1015 // e.g: x ?: y is shorthand for: x ? x : y; 1016 Succ = ConfluenceBlock; 1017 Block = NULL; 1018 CFGBlock* LHSBlock = NULL; 1019 if (C->getLHS()) { 1020 LHSBlock = Visit(C->getLHS(), asc); 1021 if (badCFG) 1022 return 0; 1023 Block = NULL; 1024 } 1025 1026 // Create the block for the RHS expression. 1027 Succ = ConfluenceBlock; 1028 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1029 if (badCFG) 1030 return 0; 1031 1032 // Create the block that will contain the condition. 1033 Block = createBlock(false); 1034 1035 // See if this is a known constant. 1036 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1037 if (LHSBlock) { 1038 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1039 } else { 1040 if (KnownVal.isFalse()) { 1041 // If we know the condition is false, add NULL as the successor for 1042 // the block containing the condition. In this case, the confluence 1043 // block will have just one predecessor. 1044 AddSuccessor(Block, 0); 1045 assert(ConfluenceBlock->pred_size() == 1); 1046 } else { 1047 // If we have no LHS expression, add the ConfluenceBlock as a direct 1048 // successor for the block containing the condition. Moreover, we need to 1049 // reverse the order of the predecessors in the ConfluenceBlock because 1050 // the RHSBlock will have been added to the succcessors already, and we 1051 // want the first predecessor to the the block containing the expression 1052 // for the case when the ternary expression evaluates to true. 1053 AddSuccessor(Block, ConfluenceBlock); 1054 assert(ConfluenceBlock->pred_size() == 2); 1055 std::reverse(ConfluenceBlock->pred_begin(), 1056 ConfluenceBlock->pred_end()); 1057 } 1058 } 1059 1060 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1061 Block->setTerminator(C); 1062 return addStmt(C->getCond()); 1063} 1064 1065CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1066 autoCreateBlock(); 1067 1068 if (DS->isSingleDecl()) { 1069 AppendStmt(Block, DS); 1070 return VisitDeclSubExpr(DS->getSingleDecl()); 1071 } 1072 1073 CFGBlock *B = 0; 1074 1075 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1076 typedef llvm::SmallVector<Decl*,10> BufTy; 1077 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1078 1079 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1080 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1081 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1082 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1083 1084 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1085 // automatically freed with the CFG. 1086 DeclGroupRef DG(*I); 1087 Decl *D = *I; 1088 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1089 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1090 1091 // Append the fake DeclStmt to block. 1092 AppendStmt(Block, DSNew); 1093 B = VisitDeclSubExpr(D); 1094 } 1095 1096 return B; 1097} 1098 1099/// VisitDeclSubExpr - Utility method to add block-level expressions for 1100/// initializers in Decls. 1101CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 1102 assert(Block); 1103 1104 VarDecl *VD = dyn_cast<VarDecl>(D); 1105 1106 if (!VD) 1107 return Block; 1108 1109 Expr *Init = VD->getInit(); 1110 1111 if (Init) { 1112 AddStmtChoice::Kind k = 1113 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 1114 : AddStmtChoice::NotAlwaysAdd; 1115 Visit(Init, AddStmtChoice(k)); 1116 } 1117 1118 // If the type of VD is a VLA, then we must process its size expressions. 1119 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1120 VA = FindVA(VA->getElementType().getTypePtr())) 1121 Block = addStmt(VA->getSizeExpr()); 1122 1123 // Remove variable from local scope. 1124 if (ScopePos && VD == *ScopePos) 1125 ++ScopePos; 1126 1127 return Block; 1128} 1129 1130CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1131 // We may see an if statement in the middle of a basic block, or it may be the 1132 // first statement we are processing. In either case, we create a new basic 1133 // block. First, we create the blocks for the then...else statements, and 1134 // then we create the block containing the if statement. If we were in the 1135 // middle of a block, we stop processing that block. That block is then the 1136 // implicit successor for the "then" and "else" clauses. 1137 1138 // Save local scope position because in case of condition variable ScopePos 1139 // won't be restored when traversing AST. 1140 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1141 1142 // Create local scope for possible condition variable. 1143 // Store scope position. Add implicit destructor. 1144 if (VarDecl* VD = I->getConditionVariable()) { 1145 LocalScope::const_iterator BeginScopePos = ScopePos; 1146 addLocalScopeForVarDecl(VD); 1147 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1148 } 1149 1150 // The block we were proccessing is now finished. Make it the successor 1151 // block. 1152 if (Block) { 1153 Succ = Block; 1154 if (badCFG) 1155 return 0; 1156 } 1157 1158 // Process the false branch. 1159 CFGBlock* ElseBlock = Succ; 1160 1161 if (Stmt* Else = I->getElse()) { 1162 SaveAndRestore<CFGBlock*> sv(Succ); 1163 1164 // NULL out Block so that the recursive call to Visit will 1165 // create a new basic block. 1166 Block = NULL; 1167 1168 // If branch is not a compound statement create implicit scope 1169 // and add destructors. 1170 if (!isa<CompoundStmt>(Else)) 1171 addLocalScopeAndDtors(Else); 1172 1173 ElseBlock = addStmt(Else); 1174 1175 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1176 ElseBlock = sv.get(); 1177 else if (Block) { 1178 if (badCFG) 1179 return 0; 1180 } 1181 } 1182 1183 // Process the true branch. 1184 CFGBlock* ThenBlock; 1185 { 1186 Stmt* Then = I->getThen(); 1187 assert(Then); 1188 SaveAndRestore<CFGBlock*> sv(Succ); 1189 Block = NULL; 1190 1191 // If branch is not a compound statement create implicit scope 1192 // and add destructors. 1193 if (!isa<CompoundStmt>(Then)) 1194 addLocalScopeAndDtors(Then); 1195 1196 ThenBlock = addStmt(Then); 1197 1198 if (!ThenBlock) { 1199 // We can reach here if the "then" body has all NullStmts. 1200 // Create an empty block so we can distinguish between true and false 1201 // branches in path-sensitive analyses. 1202 ThenBlock = createBlock(false); 1203 AddSuccessor(ThenBlock, sv.get()); 1204 } else if (Block) { 1205 if (badCFG) 1206 return 0; 1207 } 1208 } 1209 1210 // Now create a new block containing the if statement. 1211 Block = createBlock(false); 1212 1213 // Set the terminator of the new block to the If statement. 1214 Block->setTerminator(I); 1215 1216 // See if this is a known constant. 1217 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1218 1219 // Now add the successors. 1220 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1221 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1222 1223 // Add the condition as the last statement in the new block. This may create 1224 // new blocks as the condition may contain control-flow. Any newly created 1225 // blocks will be pointed to be "Block". 1226 Block = addStmt(I->getCond()); 1227 1228 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1229 // and the condition variable initialization to the CFG. 1230 if (VarDecl *VD = I->getConditionVariable()) { 1231 if (Expr *Init = VD->getInit()) { 1232 autoCreateBlock(); 1233 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1234 addStmt(Init); 1235 } 1236 } 1237 1238 return Block; 1239} 1240 1241 1242CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1243 // If we were in the middle of a block we stop processing that block. 1244 // 1245 // NOTE: If a "return" appears in the middle of a block, this means that the 1246 // code afterwards is DEAD (unreachable). We still keep a basic block 1247 // for that code; a simple "mark-and-sweep" from the entry block will be 1248 // able to report such dead blocks. 1249 1250 // Create the new block. 1251 Block = createBlock(false); 1252 1253 // The Exit block is the only successor. 1254 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1255 AddSuccessor(Block, &cfg->getExit()); 1256 1257 // Add the return statement to the block. This may create new blocks if R 1258 // contains control-flow (short-circuit operations). 1259 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1260} 1261 1262CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1263 // Get the block of the labeled statement. Add it to our map. 1264 addStmt(L->getSubStmt()); 1265 CFGBlock* LabelBlock = Block; 1266 1267 if (!LabelBlock) // This can happen when the body is empty, i.e. 1268 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1269 1270 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1271 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1272 1273 // Labels partition blocks, so this is the end of the basic block we were 1274 // processing (L is the block's label). Because this is label (and we have 1275 // already processed the substatement) there is no extra control-flow to worry 1276 // about. 1277 LabelBlock->setLabel(L); 1278 if (badCFG) 1279 return 0; 1280 1281 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1282 Block = NULL; 1283 1284 // This block is now the implicit successor of other blocks. 1285 Succ = LabelBlock; 1286 1287 return LabelBlock; 1288} 1289 1290CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1291 // Goto is a control-flow statement. Thus we stop processing the current 1292 // block and create a new one. 1293 1294 Block = createBlock(false); 1295 Block->setTerminator(G); 1296 1297 // If we already know the mapping to the label block add the successor now. 1298 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1299 1300 if (I == LabelMap.end()) 1301 // We will need to backpatch this block later. 1302 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1303 else { 1304 JumpTarget JT = I->second; 1305 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1306 AddSuccessor(Block, JT.Block); 1307 } 1308 1309 return Block; 1310} 1311 1312CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1313 CFGBlock* LoopSuccessor = NULL; 1314 1315 // Save local scope position because in case of condition variable ScopePos 1316 // won't be restored when traversing AST. 1317 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1318 1319 // Create local scope for init statement and possible condition variable. 1320 // Add destructor for init statement and condition variable. 1321 // Store scope position for continue statement. 1322 if (Stmt* Init = F->getInit()) 1323 addLocalScopeForStmt(Init); 1324 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1325 1326 if (VarDecl* VD = F->getConditionVariable()) 1327 addLocalScopeForVarDecl(VD); 1328 LocalScope::const_iterator ContinueScopePos = ScopePos; 1329 1330 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1331 1332 // "for" is a control-flow statement. Thus we stop processing the current 1333 // block. 1334 if (Block) { 1335 if (badCFG) 1336 return 0; 1337 LoopSuccessor = Block; 1338 } else 1339 LoopSuccessor = Succ; 1340 1341 // Save the current value for the break targets. 1342 // All breaks should go to the code following the loop. 1343 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1344 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1345 1346 // Because of short-circuit evaluation, the condition of the loop can span 1347 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1348 // evaluate the condition. 1349 CFGBlock* ExitConditionBlock = createBlock(false); 1350 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1351 1352 // Set the terminator for the "exit" condition block. 1353 ExitConditionBlock->setTerminator(F); 1354 1355 // Now add the actual condition to the condition block. Because the condition 1356 // itself may contain control-flow, new blocks may be created. 1357 if (Stmt* C = F->getCond()) { 1358 Block = ExitConditionBlock; 1359 EntryConditionBlock = addStmt(C); 1360 assert(Block == EntryConditionBlock || 1361 (Block == 0 && EntryConditionBlock == Succ)); 1362 1363 // If this block contains a condition variable, add both the condition 1364 // variable and initializer to the CFG. 1365 if (VarDecl *VD = F->getConditionVariable()) { 1366 if (Expr *Init = VD->getInit()) { 1367 autoCreateBlock(); 1368 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1369 EntryConditionBlock = addStmt(Init); 1370 assert(Block == EntryConditionBlock); 1371 } 1372 } 1373 1374 if (Block) { 1375 if (badCFG) 1376 return 0; 1377 } 1378 } 1379 1380 // The condition block is the implicit successor for the loop body as well as 1381 // any code above the loop. 1382 Succ = EntryConditionBlock; 1383 1384 // See if this is a known constant. 1385 TryResult KnownVal(true); 1386 1387 if (F->getCond()) 1388 KnownVal = TryEvaluateBool(F->getCond()); 1389 1390 // Now create the loop body. 1391 { 1392 assert(F->getBody()); 1393 1394 // Save the current values for Block, Succ, and continue targets. 1395 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1396 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1397 1398 // Create a new block to contain the (bottom) of the loop body. 1399 Block = NULL; 1400 1401 // Loop body should end with destructor of Condition variable (if any). 1402 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1403 1404 if (Stmt* I = F->getInc()) { 1405 // Generate increment code in its own basic block. This is the target of 1406 // continue statements. 1407 Succ = addStmt(I); 1408 } else { 1409 // No increment code. Create a special, empty, block that is used as the 1410 // target block for "looping back" to the start of the loop. 1411 assert(Succ == EntryConditionBlock); 1412 Succ = Block ? Block : createBlock(); 1413 } 1414 1415 // Finish up the increment (or empty) block if it hasn't been already. 1416 if (Block) { 1417 assert(Block == Succ); 1418 if (badCFG) 1419 return 0; 1420 Block = 0; 1421 } 1422 1423 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1424 1425 // The starting block for the loop increment is the block that should 1426 // represent the 'loop target' for looping back to the start of the loop. 1427 ContinueJumpTarget.Block->setLoopTarget(F); 1428 1429 // If body is not a compound statement create implicit scope 1430 // and add destructors. 1431 if (!isa<CompoundStmt>(F->getBody())) 1432 addLocalScopeAndDtors(F->getBody()); 1433 1434 // Now populate the body block, and in the process create new blocks as we 1435 // walk the body of the loop. 1436 CFGBlock* BodyBlock = addStmt(F->getBody()); 1437 1438 if (!BodyBlock) 1439 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1440 else if (badCFG) 1441 return 0; 1442 1443 // This new body block is a successor to our "exit" condition block. 1444 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1445 } 1446 1447 // Link up the condition block with the code that follows the loop. (the 1448 // false branch). 1449 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1450 1451 // If the loop contains initialization, create a new block for those 1452 // statements. This block can also contain statements that precede the loop. 1453 if (Stmt* I = F->getInit()) { 1454 Block = createBlock(); 1455 return addStmt(I); 1456 } else { 1457 // There is no loop initialization. We are thus basically a while loop. 1458 // NULL out Block to force lazy block construction. 1459 Block = NULL; 1460 Succ = EntryConditionBlock; 1461 return EntryConditionBlock; 1462 } 1463} 1464 1465CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1466 if (asc.alwaysAdd()) { 1467 autoCreateBlock(); 1468 AppendStmt(Block, M, asc); 1469 } 1470 return Visit(M->getBase(), 1471 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1472 : AddStmtChoice::AsLValueNotAlwaysAdd); 1473} 1474 1475CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1476 // Objective-C fast enumeration 'for' statements: 1477 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1478 // 1479 // for ( Type newVariable in collection_expression ) { statements } 1480 // 1481 // becomes: 1482 // 1483 // prologue: 1484 // 1. collection_expression 1485 // T. jump to loop_entry 1486 // loop_entry: 1487 // 1. side-effects of element expression 1488 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1489 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1490 // TB: 1491 // statements 1492 // T. jump to loop_entry 1493 // FB: 1494 // what comes after 1495 // 1496 // and 1497 // 1498 // Type existingItem; 1499 // for ( existingItem in expression ) { statements } 1500 // 1501 // becomes: 1502 // 1503 // the same with newVariable replaced with existingItem; the binding works 1504 // the same except that for one ObjCForCollectionStmt::getElement() returns 1505 // a DeclStmt and the other returns a DeclRefExpr. 1506 // 1507 1508 CFGBlock* LoopSuccessor = 0; 1509 1510 if (Block) { 1511 if (badCFG) 1512 return 0; 1513 LoopSuccessor = Block; 1514 Block = 0; 1515 } else 1516 LoopSuccessor = Succ; 1517 1518 // Build the condition blocks. 1519 CFGBlock* ExitConditionBlock = createBlock(false); 1520 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1521 1522 // Set the terminator for the "exit" condition block. 1523 ExitConditionBlock->setTerminator(S); 1524 1525 // The last statement in the block should be the ObjCForCollectionStmt, which 1526 // performs the actual binding to 'element' and determines if there are any 1527 // more items in the collection. 1528 AppendStmt(ExitConditionBlock, S); 1529 Block = ExitConditionBlock; 1530 1531 // Walk the 'element' expression to see if there are any side-effects. We 1532 // generate new blocks as necesary. We DON'T add the statement by default to 1533 // the CFG unless it contains control-flow. 1534 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1535 if (Block) { 1536 if (badCFG) 1537 return 0; 1538 Block = 0; 1539 } 1540 1541 // The condition block is the implicit successor for the loop body as well as 1542 // any code above the loop. 1543 Succ = EntryConditionBlock; 1544 1545 // Now create the true branch. 1546 { 1547 // Save the current values for Succ, continue and break targets. 1548 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1549 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1550 save_break(BreakJumpTarget); 1551 1552 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1553 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1554 1555 CFGBlock* BodyBlock = addStmt(S->getBody()); 1556 1557 if (!BodyBlock) 1558 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1559 else if (Block) { 1560 if (badCFG) 1561 return 0; 1562 } 1563 1564 // This new body block is a successor to our "exit" condition block. 1565 AddSuccessor(ExitConditionBlock, BodyBlock); 1566 } 1567 1568 // Link up the condition block with the code that follows the loop. 1569 // (the false branch). 1570 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1571 1572 // Now create a prologue block to contain the collection expression. 1573 Block = createBlock(); 1574 return addStmt(S->getCollection()); 1575} 1576 1577CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1578 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1579 1580 // Inline the body. 1581 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1582 1583 // The sync body starts its own basic block. This makes it a little easier 1584 // for diagnostic clients. 1585 if (SyncBlock) { 1586 if (badCFG) 1587 return 0; 1588 1589 Block = 0; 1590 Succ = SyncBlock; 1591 } 1592 1593 // Add the @synchronized to the CFG. 1594 autoCreateBlock(); 1595 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1596 1597 // Inline the sync expression. 1598 return addStmt(S->getSynchExpr()); 1599} 1600 1601CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1602 // FIXME 1603 return NYS(); 1604} 1605 1606CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1607 CFGBlock* LoopSuccessor = NULL; 1608 1609 // Save local scope position because in case of condition variable ScopePos 1610 // won't be restored when traversing AST. 1611 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1612 1613 // Create local scope for possible condition variable. 1614 // Store scope position for continue statement. 1615 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1616 if (VarDecl* VD = W->getConditionVariable()) { 1617 addLocalScopeForVarDecl(VD); 1618 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1619 } 1620 1621 // "while" is a control-flow statement. Thus we stop processing the current 1622 // block. 1623 if (Block) { 1624 if (badCFG) 1625 return 0; 1626 LoopSuccessor = Block; 1627 } else 1628 LoopSuccessor = Succ; 1629 1630 // Because of short-circuit evaluation, the condition of the loop can span 1631 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1632 // evaluate the condition. 1633 CFGBlock* ExitConditionBlock = createBlock(false); 1634 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1635 1636 // Set the terminator for the "exit" condition block. 1637 ExitConditionBlock->setTerminator(W); 1638 1639 // Now add the actual condition to the condition block. Because the condition 1640 // itself may contain control-flow, new blocks may be created. Thus we update 1641 // "Succ" after adding the condition. 1642 if (Stmt* C = W->getCond()) { 1643 Block = ExitConditionBlock; 1644 EntryConditionBlock = addStmt(C); 1645 assert(Block == EntryConditionBlock); 1646 1647 // If this block contains a condition variable, add both the condition 1648 // variable and initializer to the CFG. 1649 if (VarDecl *VD = W->getConditionVariable()) { 1650 if (Expr *Init = VD->getInit()) { 1651 autoCreateBlock(); 1652 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1653 EntryConditionBlock = addStmt(Init); 1654 assert(Block == EntryConditionBlock); 1655 } 1656 } 1657 1658 if (Block) { 1659 if (badCFG) 1660 return 0; 1661 } 1662 } 1663 1664 // The condition block is the implicit successor for the loop body as well as 1665 // any code above the loop. 1666 Succ = EntryConditionBlock; 1667 1668 // See if this is a known constant. 1669 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1670 1671 // Process the loop body. 1672 { 1673 assert(W->getBody()); 1674 1675 // Save the current values for Block, Succ, and continue and break targets 1676 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1677 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1678 save_break(BreakJumpTarget); 1679 1680 // Create an empty block to represent the transition block for looping back 1681 // to the head of the loop. 1682 Block = 0; 1683 assert(Succ == EntryConditionBlock); 1684 Succ = createBlock(); 1685 Succ->setLoopTarget(W); 1686 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1687 1688 // All breaks should go to the code following the loop. 1689 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1690 1691 // NULL out Block to force lazy instantiation of blocks for the body. 1692 Block = NULL; 1693 1694 // Loop body should end with destructor of Condition variable (if any). 1695 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1696 1697 // If body is not a compound statement create implicit scope 1698 // and add destructors. 1699 if (!isa<CompoundStmt>(W->getBody())) 1700 addLocalScopeAndDtors(W->getBody()); 1701 1702 // Create the body. The returned block is the entry to the loop body. 1703 CFGBlock* BodyBlock = addStmt(W->getBody()); 1704 1705 if (!BodyBlock) 1706 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1707 else if (Block) { 1708 if (badCFG) 1709 return 0; 1710 } 1711 1712 // Add the loop body entry as a successor to the condition. 1713 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1714 } 1715 1716 // Link up the condition block with the code that follows the loop. (the 1717 // false branch). 1718 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1719 1720 // There can be no more statements in the condition block since we loop back 1721 // to this block. NULL out Block to force lazy creation of another block. 1722 Block = NULL; 1723 1724 // Return the condition block, which is the dominating block for the loop. 1725 Succ = EntryConditionBlock; 1726 return EntryConditionBlock; 1727} 1728 1729 1730CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1731 // FIXME: For now we pretend that @catch and the code it contains does not 1732 // exit. 1733 return Block; 1734} 1735 1736CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1737 // FIXME: This isn't complete. We basically treat @throw like a return 1738 // statement. 1739 1740 // If we were in the middle of a block we stop processing that block. 1741 if (badCFG) 1742 return 0; 1743 1744 // Create the new block. 1745 Block = createBlock(false); 1746 1747 // The Exit block is the only successor. 1748 AddSuccessor(Block, &cfg->getExit()); 1749 1750 // Add the statement to the block. This may create new blocks if S contains 1751 // control-flow (short-circuit operations). 1752 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1753} 1754 1755CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1756 // If we were in the middle of a block we stop processing that block. 1757 if (badCFG) 1758 return 0; 1759 1760 // Create the new block. 1761 Block = createBlock(false); 1762 1763 if (TryTerminatedBlock) 1764 // The current try statement is the only successor. 1765 AddSuccessor(Block, TryTerminatedBlock); 1766 else 1767 // otherwise the Exit block is the only successor. 1768 AddSuccessor(Block, &cfg->getExit()); 1769 1770 // Add the statement to the block. This may create new blocks if S contains 1771 // control-flow (short-circuit operations). 1772 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1773} 1774 1775CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1776 CFGBlock* LoopSuccessor = NULL; 1777 1778 // "do...while" is a control-flow statement. Thus we stop processing the 1779 // current block. 1780 if (Block) { 1781 if (badCFG) 1782 return 0; 1783 LoopSuccessor = Block; 1784 } else 1785 LoopSuccessor = Succ; 1786 1787 // Because of short-circuit evaluation, the condition of the loop can span 1788 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1789 // evaluate the condition. 1790 CFGBlock* ExitConditionBlock = createBlock(false); 1791 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1792 1793 // Set the terminator for the "exit" condition block. 1794 ExitConditionBlock->setTerminator(D); 1795 1796 // Now add the actual condition to the condition block. Because the condition 1797 // itself may contain control-flow, new blocks may be created. 1798 if (Stmt* C = D->getCond()) { 1799 Block = ExitConditionBlock; 1800 EntryConditionBlock = addStmt(C); 1801 if (Block) { 1802 if (badCFG) 1803 return 0; 1804 } 1805 } 1806 1807 // The condition block is the implicit successor for the loop body. 1808 Succ = EntryConditionBlock; 1809 1810 // See if this is a known constant. 1811 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1812 1813 // Process the loop body. 1814 CFGBlock* BodyBlock = NULL; 1815 { 1816 assert(D->getBody()); 1817 1818 // Save the current values for Block, Succ, and continue and break targets 1819 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1820 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1821 save_break(BreakJumpTarget); 1822 1823 // All continues within this loop should go to the condition block 1824 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1825 1826 // All breaks should go to the code following the loop. 1827 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1828 1829 // NULL out Block to force lazy instantiation of blocks for the body. 1830 Block = NULL; 1831 1832 // If body is not a compound statement create implicit scope 1833 // and add destructors. 1834 if (!isa<CompoundStmt>(D->getBody())) 1835 addLocalScopeAndDtors(D->getBody()); 1836 1837 // Create the body. The returned block is the entry to the loop body. 1838 BodyBlock = addStmt(D->getBody()); 1839 1840 if (!BodyBlock) 1841 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1842 else if (Block) { 1843 if (badCFG) 1844 return 0; 1845 } 1846 1847 if (!KnownVal.isFalse()) { 1848 // Add an intermediate block between the BodyBlock and the 1849 // ExitConditionBlock to represent the "loop back" transition. Create an 1850 // empty block to represent the transition block for looping back to the 1851 // head of the loop. 1852 // FIXME: Can we do this more efficiently without adding another block? 1853 Block = NULL; 1854 Succ = BodyBlock; 1855 CFGBlock *LoopBackBlock = createBlock(); 1856 LoopBackBlock->setLoopTarget(D); 1857 1858 // Add the loop body entry as a successor to the condition. 1859 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1860 } 1861 else 1862 AddSuccessor(ExitConditionBlock, NULL); 1863 } 1864 1865 // Link up the condition block with the code that follows the loop. 1866 // (the false branch). 1867 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1868 1869 // There can be no more statements in the body block(s) since we loop back to 1870 // the body. NULL out Block to force lazy creation of another block. 1871 Block = NULL; 1872 1873 // Return the loop body, which is the dominating block for the loop. 1874 Succ = BodyBlock; 1875 return BodyBlock; 1876} 1877 1878CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1879 // "continue" is a control-flow statement. Thus we stop processing the 1880 // current block. 1881 if (badCFG) 1882 return 0; 1883 1884 // Now create a new block that ends with the continue statement. 1885 Block = createBlock(false); 1886 Block->setTerminator(C); 1887 1888 // If there is no target for the continue, then we are looking at an 1889 // incomplete AST. This means the CFG cannot be constructed. 1890 if (ContinueJumpTarget.Block) { 1891 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1892 AddSuccessor(Block, ContinueJumpTarget.Block); 1893 } else 1894 badCFG = true; 1895 1896 return Block; 1897} 1898 1899CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1900 AddStmtChoice asc) { 1901 1902 if (asc.alwaysAdd()) { 1903 autoCreateBlock(); 1904 AppendStmt(Block, E); 1905 } 1906 1907 // VLA types have expressions that must be evaluated. 1908 if (E->isArgumentType()) { 1909 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1910 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1911 addStmt(VA->getSizeExpr()); 1912 } 1913 1914 return Block; 1915} 1916 1917/// VisitStmtExpr - Utility method to handle (nested) statement 1918/// expressions (a GCC extension). 1919CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 1920 if (asc.alwaysAdd()) { 1921 autoCreateBlock(); 1922 AppendStmt(Block, SE); 1923 } 1924 return VisitCompoundStmt(SE->getSubStmt()); 1925} 1926 1927CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1928 // "switch" is a control-flow statement. Thus we stop processing the current 1929 // block. 1930 CFGBlock* SwitchSuccessor = NULL; 1931 1932 // Save local scope position because in case of condition variable ScopePos 1933 // won't be restored when traversing AST. 1934 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1935 1936 // Create local scope for possible condition variable. 1937 // Store scope position. Add implicit destructor. 1938 if (VarDecl* VD = Terminator->getConditionVariable()) { 1939 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 1940 addLocalScopeForVarDecl(VD); 1941 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 1942 } 1943 1944 if (Block) { 1945 if (badCFG) 1946 return 0; 1947 SwitchSuccessor = Block; 1948 } else SwitchSuccessor = Succ; 1949 1950 // Save the current "switch" context. 1951 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1952 save_default(DefaultCaseBlock); 1953 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1954 1955 // Set the "default" case to be the block after the switch statement. If the 1956 // switch statement contains a "default:", this value will be overwritten with 1957 // the block for that code. 1958 DefaultCaseBlock = SwitchSuccessor; 1959 1960 // Create a new block that will contain the switch statement. 1961 SwitchTerminatedBlock = createBlock(false); 1962 1963 // Now process the switch body. The code after the switch is the implicit 1964 // successor. 1965 Succ = SwitchSuccessor; 1966 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 1967 1968 // When visiting the body, the case statements should automatically get linked 1969 // up to the switch. We also don't keep a pointer to the body, since all 1970 // control-flow from the switch goes to case/default statements. 1971 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 1972 Block = NULL; 1973 1974 // If body is not a compound statement create implicit scope 1975 // and add destructors. 1976 if (!isa<CompoundStmt>(Terminator->getBody())) 1977 addLocalScopeAndDtors(Terminator->getBody()); 1978 1979 addStmt(Terminator->getBody()); 1980 if (Block) { 1981 if (badCFG) 1982 return 0; 1983 } 1984 1985 // If we have no "default:" case, the default transition is to the code 1986 // following the switch body. 1987 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1988 1989 // Add the terminator and condition in the switch block. 1990 SwitchTerminatedBlock->setTerminator(Terminator); 1991 assert(Terminator->getCond() && "switch condition must be non-NULL"); 1992 Block = SwitchTerminatedBlock; 1993 Block = addStmt(Terminator->getCond()); 1994 1995 // Finally, if the SwitchStmt contains a condition variable, add both the 1996 // SwitchStmt and the condition variable initialization to the CFG. 1997 if (VarDecl *VD = Terminator->getConditionVariable()) { 1998 if (Expr *Init = VD->getInit()) { 1999 autoCreateBlock(); 2000 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 2001 addStmt(Init); 2002 } 2003 } 2004 2005 return Block; 2006} 2007 2008CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2009 // CaseStmts are essentially labels, so they are the first statement in a 2010 // block. 2011 CFGBlock *TopBlock = 0, *LastBlock = 0; 2012 2013 if (Stmt *Sub = CS->getSubStmt()) { 2014 // For deeply nested chains of CaseStmts, instead of doing a recursion 2015 // (which can blow out the stack), manually unroll and create blocks 2016 // along the way. 2017 while (isa<CaseStmt>(Sub)) { 2018 CFGBlock *CurrentBlock = createBlock(false); 2019 CurrentBlock->setLabel(CS); 2020 2021 if (TopBlock) 2022 AddSuccessor(LastBlock, CurrentBlock); 2023 else 2024 TopBlock = CurrentBlock; 2025 2026 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2027 LastBlock = CurrentBlock; 2028 2029 CS = cast<CaseStmt>(Sub); 2030 Sub = CS->getSubStmt(); 2031 } 2032 2033 addStmt(Sub); 2034 } 2035 2036 CFGBlock* CaseBlock = Block; 2037 if (!CaseBlock) 2038 CaseBlock = createBlock(); 2039 2040 // Cases statements partition blocks, so this is the top of the basic block we 2041 // were processing (the "case XXX:" is the label). 2042 CaseBlock->setLabel(CS); 2043 2044 if (badCFG) 2045 return 0; 2046 2047 // Add this block to the list of successors for the block with the switch 2048 // statement. 2049 assert(SwitchTerminatedBlock); 2050 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2051 2052 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2053 Block = NULL; 2054 2055 if (TopBlock) { 2056 AddSuccessor(LastBlock, CaseBlock); 2057 Succ = TopBlock; 2058 } 2059 else { 2060 // This block is now the implicit successor of other blocks. 2061 Succ = CaseBlock; 2062 } 2063 2064 return Succ; 2065} 2066 2067CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2068 if (Terminator->getSubStmt()) 2069 addStmt(Terminator->getSubStmt()); 2070 2071 DefaultCaseBlock = Block; 2072 2073 if (!DefaultCaseBlock) 2074 DefaultCaseBlock = createBlock(); 2075 2076 // Default statements partition blocks, so this is the top of the basic block 2077 // we were processing (the "default:" is the label). 2078 DefaultCaseBlock->setLabel(Terminator); 2079 2080 if (badCFG) 2081 return 0; 2082 2083 // Unlike case statements, we don't add the default block to the successors 2084 // for the switch statement immediately. This is done when we finish 2085 // processing the switch statement. This allows for the default case 2086 // (including a fall-through to the code after the switch statement) to always 2087 // be the last successor of a switch-terminated block. 2088 2089 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2090 Block = NULL; 2091 2092 // This block is now the implicit successor of other blocks. 2093 Succ = DefaultCaseBlock; 2094 2095 return DefaultCaseBlock; 2096} 2097 2098CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2099 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2100 // current block. 2101 CFGBlock* TrySuccessor = NULL; 2102 2103 if (Block) { 2104 if (badCFG) 2105 return 0; 2106 TrySuccessor = Block; 2107 } else TrySuccessor = Succ; 2108 2109 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2110 2111 // Create a new block that will contain the try statement. 2112 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2113 // Add the terminator in the try block. 2114 NewTryTerminatedBlock->setTerminator(Terminator); 2115 2116 bool HasCatchAll = false; 2117 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2118 // The code after the try is the implicit successor. 2119 Succ = TrySuccessor; 2120 CXXCatchStmt *CS = Terminator->getHandler(h); 2121 if (CS->getExceptionDecl() == 0) { 2122 HasCatchAll = true; 2123 } 2124 Block = NULL; 2125 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2126 if (CatchBlock == 0) 2127 return 0; 2128 // Add this block to the list of successors for the block with the try 2129 // statement. 2130 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2131 } 2132 if (!HasCatchAll) { 2133 if (PrevTryTerminatedBlock) 2134 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2135 else 2136 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2137 } 2138 2139 // The code after the try is the implicit successor. 2140 Succ = TrySuccessor; 2141 2142 // Save the current "try" context. 2143 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2144 TryTerminatedBlock = NewTryTerminatedBlock; 2145 2146 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2147 Block = NULL; 2148 Block = addStmt(Terminator->getTryBlock()); 2149 return Block; 2150} 2151 2152CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2153 // CXXCatchStmt are treated like labels, so they are the first statement in a 2154 // block. 2155 2156 // Save local scope position because in case of exception variable ScopePos 2157 // won't be restored when traversing AST. 2158 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2159 2160 // Create local scope for possible exception variable. 2161 // Store scope position. Add implicit destructor. 2162 if (VarDecl* VD = CS->getExceptionDecl()) { 2163 LocalScope::const_iterator BeginScopePos = ScopePos; 2164 addLocalScopeForVarDecl(VD); 2165 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2166 } 2167 2168 if (CS->getHandlerBlock()) 2169 addStmt(CS->getHandlerBlock()); 2170 2171 CFGBlock* CatchBlock = Block; 2172 if (!CatchBlock) 2173 CatchBlock = createBlock(); 2174 2175 CatchBlock->setLabel(CS); 2176 2177 if (badCFG) 2178 return 0; 2179 2180 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2181 Block = NULL; 2182 2183 return CatchBlock; 2184} 2185 2186CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2187 AddStmtChoice asc) { 2188 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2189 : AddStmtChoice::AlwaysAdd; 2190 autoCreateBlock(); 2191 AppendStmt(Block, C, AddStmtChoice(K)); 2192 return VisitChildren(C); 2193} 2194 2195CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2196 // Lazily create the indirect-goto dispatch block if there isn't one already. 2197 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2198 2199 if (!IBlock) { 2200 IBlock = createBlock(false); 2201 cfg->setIndirectGotoBlock(IBlock); 2202 } 2203 2204 // IndirectGoto is a control-flow statement. Thus we stop processing the 2205 // current block and create a new one. 2206 if (badCFG) 2207 return 0; 2208 2209 Block = createBlock(false); 2210 Block->setTerminator(I); 2211 AddSuccessor(Block, IBlock); 2212 return addStmt(I->getTarget()); 2213} 2214 2215} // end anonymous namespace 2216 2217/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2218/// no successors or predecessors. If this is the first block created in the 2219/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2220CFGBlock* CFG::createBlock() { 2221 bool first_block = begin() == end(); 2222 2223 // Create the block. 2224 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2225 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2226 Blocks.push_back(Mem, BlkBVC); 2227 2228 // If this is the first block, set it as the Entry and Exit. 2229 if (first_block) 2230 Entry = Exit = &back(); 2231 2232 // Return the block. 2233 return &back(); 2234} 2235 2236/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2237/// CFG is returned to the caller. 2238CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2239 BuildOptions BO) { 2240 CFGBuilder Builder; 2241 return Builder.buildCFG(D, Statement, C, BO); 2242} 2243 2244//===----------------------------------------------------------------------===// 2245// CFG: Queries for BlkExprs. 2246//===----------------------------------------------------------------------===// 2247 2248namespace { 2249 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2250} 2251 2252static void FindSubExprAssignments(Stmt *S, 2253 llvm::SmallPtrSet<Expr*,50>& Set) { 2254 if (!S) 2255 return; 2256 2257 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2258 Stmt *child = *I; 2259 if (!child) 2260 continue; 2261 2262 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2263 if (B->isAssignmentOp()) Set.insert(B); 2264 2265 FindSubExprAssignments(child, Set); 2266 } 2267} 2268 2269static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2270 BlkExprMapTy* M = new BlkExprMapTy(); 2271 2272 // Look for assignments that are used as subexpressions. These are the only 2273 // assignments that we want to *possibly* register as a block-level 2274 // expression. Basically, if an assignment occurs both in a subexpression and 2275 // at the block-level, it is a block-level expression. 2276 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2277 2278 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2279 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2280 if (CFGStmt S = BI->getAs<CFGStmt>()) 2281 FindSubExprAssignments(S, SubExprAssignments); 2282 2283 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2284 2285 // Iterate over the statements again on identify the Expr* and Stmt* at the 2286 // block-level that are block-level expressions. 2287 2288 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2289 CFGStmt CS = BI->getAs<CFGStmt>(); 2290 if (!CS.isValid()) 2291 continue; 2292 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2293 2294 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2295 // Assignment expressions that are not nested within another 2296 // expression are really "statements" whose value is never used by 2297 // another expression. 2298 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2299 continue; 2300 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2301 // Special handling for statement expressions. The last statement in 2302 // the statement expression is also a block-level expr. 2303 const CompoundStmt* C = Terminator->getSubStmt(); 2304 if (!C->body_empty()) { 2305 unsigned x = M->size(); 2306 (*M)[C->body_back()] = x; 2307 } 2308 } 2309 2310 unsigned x = M->size(); 2311 (*M)[Exp] = x; 2312 } 2313 } 2314 2315 // Look at terminators. The condition is a block-level expression. 2316 2317 Stmt* S = (*I)->getTerminatorCondition(); 2318 2319 if (S && M->find(S) == M->end()) { 2320 unsigned x = M->size(); 2321 (*M)[S] = x; 2322 } 2323 } 2324 2325 return M; 2326} 2327 2328CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2329 assert(S != NULL); 2330 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2331 2332 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2333 BlkExprMapTy::iterator I = M->find(S); 2334 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2335} 2336 2337unsigned CFG::getNumBlkExprs() { 2338 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2339 return M->size(); 2340 else { 2341 // We assume callers interested in the number of BlkExprs will want 2342 // the map constructed if it doesn't already exist. 2343 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2344 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2345 } 2346} 2347 2348//===----------------------------------------------------------------------===// 2349// Filtered walking of the CFG. 2350//===----------------------------------------------------------------------===// 2351 2352bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2353 const CFGBlock *From, const CFGBlock *To) { 2354 2355 if (F.IgnoreDefaultsWithCoveredEnums) { 2356 // If the 'To' has no label or is labeled but the label isn't a 2357 // CaseStmt then filter this edge. 2358 if (const SwitchStmt *S = 2359 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2360 if (S->isAllEnumCasesCovered()) { 2361 const Stmt *L = To->getLabel(); 2362 if (!L || !isa<CaseStmt>(L)) 2363 return true; 2364 } 2365 } 2366 } 2367 2368 return false; 2369} 2370 2371//===----------------------------------------------------------------------===// 2372// Cleanup: CFG dstor. 2373//===----------------------------------------------------------------------===// 2374 2375CFG::~CFG() { 2376 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2377} 2378 2379//===----------------------------------------------------------------------===// 2380// CFG pretty printing 2381//===----------------------------------------------------------------------===// 2382 2383namespace { 2384 2385class StmtPrinterHelper : public PrinterHelper { 2386 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2387 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2388 StmtMapTy StmtMap; 2389 DeclMapTy DeclMap; 2390 signed CurrentBlock; 2391 unsigned CurrentStmt; 2392 const LangOptions &LangOpts; 2393public: 2394 2395 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2396 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2397 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2398 unsigned j = 1; 2399 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2400 BI != BEnd; ++BI, ++j ) { 2401 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2402 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2403 StmtMap[SE] = P; 2404 2405 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2406 DeclMap[DS->getSingleDecl()] = P; 2407 2408 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2409 if (VarDecl* VD = IS->getConditionVariable()) 2410 DeclMap[VD] = P; 2411 2412 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2413 if (VarDecl* VD = FS->getConditionVariable()) 2414 DeclMap[VD] = P; 2415 2416 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2417 if (VarDecl* VD = WS->getConditionVariable()) 2418 DeclMap[VD] = P; 2419 2420 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2421 if (VarDecl* VD = SS->getConditionVariable()) 2422 DeclMap[VD] = P; 2423 2424 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2425 if (VarDecl* VD = CS->getExceptionDecl()) 2426 DeclMap[VD] = P; 2427 } 2428 } 2429 } 2430 } 2431 } 2432 2433 virtual ~StmtPrinterHelper() {} 2434 2435 const LangOptions &getLangOpts() const { return LangOpts; } 2436 void setBlockID(signed i) { CurrentBlock = i; } 2437 void setStmtID(unsigned i) { CurrentStmt = i; } 2438 2439 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2440 StmtMapTy::iterator I = StmtMap.find(S); 2441 2442 if (I == StmtMap.end()) 2443 return false; 2444 2445 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2446 && I->second.second == CurrentStmt) { 2447 return false; 2448 } 2449 2450 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2451 return true; 2452 } 2453 2454 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2455 DeclMapTy::iterator I = DeclMap.find(D); 2456 2457 if (I == DeclMap.end()) 2458 return false; 2459 2460 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2461 && I->second.second == CurrentStmt) { 2462 return false; 2463 } 2464 2465 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2466 return true; 2467 } 2468}; 2469} // end anonymous namespace 2470 2471 2472namespace { 2473class CFGBlockTerminatorPrint 2474 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2475 2476 llvm::raw_ostream& OS; 2477 StmtPrinterHelper* Helper; 2478 PrintingPolicy Policy; 2479public: 2480 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2481 const PrintingPolicy &Policy) 2482 : OS(os), Helper(helper), Policy(Policy) {} 2483 2484 void VisitIfStmt(IfStmt* I) { 2485 OS << "if "; 2486 I->getCond()->printPretty(OS,Helper,Policy); 2487 } 2488 2489 // Default case. 2490 void VisitStmt(Stmt* Terminator) { 2491 Terminator->printPretty(OS, Helper, Policy); 2492 } 2493 2494 void VisitForStmt(ForStmt* F) { 2495 OS << "for (" ; 2496 if (F->getInit()) 2497 OS << "..."; 2498 OS << "; "; 2499 if (Stmt* C = F->getCond()) 2500 C->printPretty(OS, Helper, Policy); 2501 OS << "; "; 2502 if (F->getInc()) 2503 OS << "..."; 2504 OS << ")"; 2505 } 2506 2507 void VisitWhileStmt(WhileStmt* W) { 2508 OS << "while " ; 2509 if (Stmt* C = W->getCond()) 2510 C->printPretty(OS, Helper, Policy); 2511 } 2512 2513 void VisitDoStmt(DoStmt* D) { 2514 OS << "do ... while "; 2515 if (Stmt* C = D->getCond()) 2516 C->printPretty(OS, Helper, Policy); 2517 } 2518 2519 void VisitSwitchStmt(SwitchStmt* Terminator) { 2520 OS << "switch "; 2521 Terminator->getCond()->printPretty(OS, Helper, Policy); 2522 } 2523 2524 void VisitCXXTryStmt(CXXTryStmt* CS) { 2525 OS << "try ..."; 2526 } 2527 2528 void VisitConditionalOperator(ConditionalOperator* C) { 2529 C->getCond()->printPretty(OS, Helper, Policy); 2530 OS << " ? ... : ..."; 2531 } 2532 2533 void VisitChooseExpr(ChooseExpr* C) { 2534 OS << "__builtin_choose_expr( "; 2535 C->getCond()->printPretty(OS, Helper, Policy); 2536 OS << " )"; 2537 } 2538 2539 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2540 OS << "goto *"; 2541 I->getTarget()->printPretty(OS, Helper, Policy); 2542 } 2543 2544 void VisitBinaryOperator(BinaryOperator* B) { 2545 if (!B->isLogicalOp()) { 2546 VisitExpr(B); 2547 return; 2548 } 2549 2550 B->getLHS()->printPretty(OS, Helper, Policy); 2551 2552 switch (B->getOpcode()) { 2553 case BO_LOr: 2554 OS << " || ..."; 2555 return; 2556 case BO_LAnd: 2557 OS << " && ..."; 2558 return; 2559 default: 2560 assert(false && "Invalid logical operator."); 2561 } 2562 } 2563 2564 void VisitExpr(Expr* E) { 2565 E->printPretty(OS, Helper, Policy); 2566 } 2567}; 2568} // end anonymous namespace 2569 2570static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2571 const CFGElement &E) { 2572 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2573 Stmt *S = CS; 2574 2575 if (Helper) { 2576 2577 // special printing for statement-expressions. 2578 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2579 CompoundStmt* Sub = SE->getSubStmt(); 2580 2581 if (Sub->child_begin() != Sub->child_end()) { 2582 OS << "({ ... ; "; 2583 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2584 OS << " })\n"; 2585 return; 2586 } 2587 } 2588 // special printing for comma expressions. 2589 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2590 if (B->getOpcode() == BO_Comma) { 2591 OS << "... , "; 2592 Helper->handledStmt(B->getRHS(),OS); 2593 OS << '\n'; 2594 return; 2595 } 2596 } 2597 } 2598 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2599 2600 if (isa<CXXOperatorCallExpr>(S)) { 2601 OS << " (OperatorCall)"; 2602 } 2603 else if (isa<CXXBindTemporaryExpr>(S)) { 2604 OS << " (BindTemporary)"; 2605 } 2606 2607 // Expressions need a newline. 2608 if (isa<Expr>(S)) 2609 OS << '\n'; 2610 2611 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2612 CXXBaseOrMemberInitializer* I = IE; 2613 if (I->isBaseInitializer()) 2614 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2615 else OS << I->getMember()->getName(); 2616 2617 OS << "("; 2618 if (Expr* IE = I->getInit()) 2619 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2620 OS << ")"; 2621 2622 if (I->isBaseInitializer()) 2623 OS << " (Base initializer)\n"; 2624 else OS << " (Member initializer)\n"; 2625 2626 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2627 VarDecl* VD = DE.getVarDecl(); 2628 Helper->handleDecl(VD, OS); 2629 2630 Type* T = VD->getType().getTypePtr(); 2631 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2632 T = RT->getPointeeType().getTypePtr(); 2633 2634 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2635 OS << " (Implicit destructor)\n"; 2636 } 2637 } 2638 2639static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2640 const CFGBlock& B, 2641 StmtPrinterHelper* Helper, bool print_edges) { 2642 2643 if (Helper) Helper->setBlockID(B.getBlockID()); 2644 2645 // Print the header. 2646 OS << "\n [ B" << B.getBlockID(); 2647 2648 if (&B == &cfg->getEntry()) 2649 OS << " (ENTRY) ]\n"; 2650 else if (&B == &cfg->getExit()) 2651 OS << " (EXIT) ]\n"; 2652 else if (&B == cfg->getIndirectGotoBlock()) 2653 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2654 else 2655 OS << " ]\n"; 2656 2657 // Print the label of this block. 2658 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2659 2660 if (print_edges) 2661 OS << " "; 2662 2663 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2664 OS << L->getName(); 2665 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2666 OS << "case "; 2667 C->getLHS()->printPretty(OS, Helper, 2668 PrintingPolicy(Helper->getLangOpts())); 2669 if (C->getRHS()) { 2670 OS << " ... "; 2671 C->getRHS()->printPretty(OS, Helper, 2672 PrintingPolicy(Helper->getLangOpts())); 2673 } 2674 } else if (isa<DefaultStmt>(Label)) 2675 OS << "default"; 2676 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2677 OS << "catch ("; 2678 if (CS->getExceptionDecl()) 2679 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2680 0); 2681 else 2682 OS << "..."; 2683 OS << ")"; 2684 2685 } else 2686 assert(false && "Invalid label statement in CFGBlock."); 2687 2688 OS << ":\n"; 2689 } 2690 2691 // Iterate through the statements in the block and print them. 2692 unsigned j = 1; 2693 2694 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2695 I != E ; ++I, ++j ) { 2696 2697 // Print the statement # in the basic block and the statement itself. 2698 if (print_edges) 2699 OS << " "; 2700 2701 OS << llvm::format("%3d", j) << ": "; 2702 2703 if (Helper) 2704 Helper->setStmtID(j); 2705 2706 print_elem(OS,Helper,*I); 2707 } 2708 2709 // Print the terminator of this block. 2710 if (B.getTerminator()) { 2711 if (print_edges) 2712 OS << " "; 2713 2714 OS << " T: "; 2715 2716 if (Helper) Helper->setBlockID(-1); 2717 2718 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2719 PrintingPolicy(Helper->getLangOpts())); 2720 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2721 OS << '\n'; 2722 } 2723 2724 if (print_edges) { 2725 // Print the predecessors of this block. 2726 OS << " Predecessors (" << B.pred_size() << "):"; 2727 unsigned i = 0; 2728 2729 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2730 I != E; ++I, ++i) { 2731 2732 if (i == 8 || (i-8) == 0) 2733 OS << "\n "; 2734 2735 OS << " B" << (*I)->getBlockID(); 2736 } 2737 2738 OS << '\n'; 2739 2740 // Print the successors of this block. 2741 OS << " Successors (" << B.succ_size() << "):"; 2742 i = 0; 2743 2744 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2745 I != E; ++I, ++i) { 2746 2747 if (i == 8 || (i-8) % 10 == 0) 2748 OS << "\n "; 2749 2750 if (*I) 2751 OS << " B" << (*I)->getBlockID(); 2752 else 2753 OS << " NULL"; 2754 } 2755 2756 OS << '\n'; 2757 } 2758} 2759 2760 2761/// dump - A simple pretty printer of a CFG that outputs to stderr. 2762void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2763 2764/// print - A simple pretty printer of a CFG that outputs to an ostream. 2765void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2766 StmtPrinterHelper Helper(this, LO); 2767 2768 // Print the entry block. 2769 print_block(OS, this, getEntry(), &Helper, true); 2770 2771 // Iterate through the CFGBlocks and print them one by one. 2772 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2773 // Skip the entry block, because we already printed it. 2774 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2775 continue; 2776 2777 print_block(OS, this, **I, &Helper, true); 2778 } 2779 2780 // Print the exit block. 2781 print_block(OS, this, getExit(), &Helper, true); 2782 OS.flush(); 2783} 2784 2785/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2786void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2787 print(llvm::errs(), cfg, LO); 2788} 2789 2790/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2791/// Generally this will only be called from CFG::print. 2792void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2793 const LangOptions &LO) const { 2794 StmtPrinterHelper Helper(cfg, LO); 2795 print_block(OS, cfg, *this, &Helper, true); 2796} 2797 2798/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2799void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2800 const LangOptions &LO) const { 2801 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2802 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2803} 2804 2805Stmt* CFGBlock::getTerminatorCondition() { 2806 2807 if (!Terminator) 2808 return NULL; 2809 2810 Expr* E = NULL; 2811 2812 switch (Terminator->getStmtClass()) { 2813 default: 2814 break; 2815 2816 case Stmt::ForStmtClass: 2817 E = cast<ForStmt>(Terminator)->getCond(); 2818 break; 2819 2820 case Stmt::WhileStmtClass: 2821 E = cast<WhileStmt>(Terminator)->getCond(); 2822 break; 2823 2824 case Stmt::DoStmtClass: 2825 E = cast<DoStmt>(Terminator)->getCond(); 2826 break; 2827 2828 case Stmt::IfStmtClass: 2829 E = cast<IfStmt>(Terminator)->getCond(); 2830 break; 2831 2832 case Stmt::ChooseExprClass: 2833 E = cast<ChooseExpr>(Terminator)->getCond(); 2834 break; 2835 2836 case Stmt::IndirectGotoStmtClass: 2837 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2838 break; 2839 2840 case Stmt::SwitchStmtClass: 2841 E = cast<SwitchStmt>(Terminator)->getCond(); 2842 break; 2843 2844 case Stmt::ConditionalOperatorClass: 2845 E = cast<ConditionalOperator>(Terminator)->getCond(); 2846 break; 2847 2848 case Stmt::BinaryOperatorClass: // '&&' and '||' 2849 E = cast<BinaryOperator>(Terminator)->getLHS(); 2850 break; 2851 2852 case Stmt::ObjCForCollectionStmtClass: 2853 return Terminator; 2854 } 2855 2856 return E ? E->IgnoreParens() : NULL; 2857} 2858 2859bool CFGBlock::hasBinaryBranchTerminator() const { 2860 2861 if (!Terminator) 2862 return false; 2863 2864 Expr* E = NULL; 2865 2866 switch (Terminator->getStmtClass()) { 2867 default: 2868 return false; 2869 2870 case Stmt::ForStmtClass: 2871 case Stmt::WhileStmtClass: 2872 case Stmt::DoStmtClass: 2873 case Stmt::IfStmtClass: 2874 case Stmt::ChooseExprClass: 2875 case Stmt::ConditionalOperatorClass: 2876 case Stmt::BinaryOperatorClass: 2877 return true; 2878 } 2879 2880 return E ? E->IgnoreParens() : NULL; 2881} 2882 2883 2884//===----------------------------------------------------------------------===// 2885// CFG Graphviz Visualization 2886//===----------------------------------------------------------------------===// 2887 2888 2889#ifndef NDEBUG 2890static StmtPrinterHelper* GraphHelper; 2891#endif 2892 2893void CFG::viewCFG(const LangOptions &LO) const { 2894#ifndef NDEBUG 2895 StmtPrinterHelper H(this, LO); 2896 GraphHelper = &H; 2897 llvm::ViewGraph(this,"CFG"); 2898 GraphHelper = NULL; 2899#endif 2900} 2901 2902namespace llvm { 2903template<> 2904struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2905 2906 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2907 2908 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 2909 2910#ifndef NDEBUG 2911 std::string OutSStr; 2912 llvm::raw_string_ostream Out(OutSStr); 2913 print_block(Out,Graph, *Node, GraphHelper, false); 2914 std::string& OutStr = Out.str(); 2915 2916 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2917 2918 // Process string output to make it nicer... 2919 for (unsigned i = 0; i != OutStr.length(); ++i) 2920 if (OutStr[i] == '\n') { // Left justify 2921 OutStr[i] = '\\'; 2922 OutStr.insert(OutStr.begin()+i+1, 'l'); 2923 } 2924 2925 return OutStr; 2926#else 2927 return ""; 2928#endif 2929 } 2930}; 2931} // end namespace llvm 2932