CFG.cpp revision fcb72ac985c26372315fabc08d43d6f66ff906b4
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39class AddStmtChoice { 40public: 41 enum Kind { NotAlwaysAdd = 0, 42 AlwaysAdd = 1, 43 AsLValueNotAlwaysAdd = 2, 44 AlwaysAddAsLValue = 3 }; 45 46 AddStmtChoice(Kind kind) : k(kind) {} 47 48 bool alwaysAdd() const { return (unsigned)k & 0x1; } 49 bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } 50 51private: 52 Kind k; 53}; 54 55/// LocalScope - Node in tree of local scopes created for C++ implicit 56/// destructor calls generation. It contains list of automatic variables 57/// declared in the scope and link to position in previous scope this scope 58/// began in. 59/// 60/// The process of creating local scopes is as follows: 61/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 62/// - Before processing statements in scope (e.g. CompoundStmt) create 63/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 64/// and set CFGBuilder::ScopePos to the end of new scope, 65/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 66/// at this VarDecl, 67/// - For every normal (without jump) end of scope add to CFGBlock destructors 68/// for objects in the current scope, 69/// - For every jump add to CFGBlock destructors for objects 70/// between CFGBuilder::ScopePos and local scope position saved for jump 71/// target. Thanks to C++ restrictions on goto jumps we can be sure that 72/// jump target position will be on the path to root from CFGBuilder::ScopePos 73/// (adding any variable that doesn't need constructor to be called to 74/// LocalScope can break this assumption), 75/// 76class LocalScope { 77public: 78 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 79 80 /// const_iterator - Iterates local scope backwards and jumps to previous 81 /// scope on reaching the beginning of currently iterated scope. 82 class const_iterator { 83 const LocalScope* Scope; 84 85 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 86 /// Invalid iterator (with null Scope) has VarIter equal to 0. 87 unsigned VarIter; 88 89 public: 90 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 91 /// Incrementing invalid iterator is allowed and will result in invalid 92 /// iterator. 93 const_iterator() 94 : Scope(NULL), VarIter(0) {} 95 96 /// Create valid iterator. In case when S.Prev is an invalid iterator and 97 /// I is equal to 0, this will create invalid iterator. 98 const_iterator(const LocalScope& S, unsigned I) 99 : Scope(&S), VarIter(I) { 100 // Iterator to "end" of scope is not allowed. Handle it by going up 101 // in scopes tree possibly up to invalid iterator in the root. 102 if (VarIter == 0 && Scope) 103 *this = Scope->Prev; 104 } 105 106 VarDecl* const* operator->() const { 107 assert (Scope && "Dereferencing invalid iterator is not allowed"); 108 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 109 return &Scope->Vars[VarIter - 1]; 110 } 111 VarDecl* operator*() const { 112 return *this->operator->(); 113 } 114 115 const_iterator& operator++() { 116 if (!Scope) 117 return *this; 118 119 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 120 --VarIter; 121 if (VarIter == 0) 122 *this = Scope->Prev; 123 return *this; 124 } 125 const_iterator operator++(int) { 126 const_iterator P = *this; 127 ++*this; 128 return P; 129 } 130 131 bool operator==(const const_iterator& rhs) const { 132 return Scope == rhs.Scope && VarIter == rhs.VarIter; 133 } 134 bool operator!=(const const_iterator& rhs) const { 135 return !(*this == rhs); 136 } 137 138 operator bool() const { 139 return *this != const_iterator(); 140 } 141 142 int distance(const_iterator L); 143 }; 144 145 friend class const_iterator; 146 147private: 148 /// Automatic variables in order of declaration. 149 AutomaticVarsTy Vars; 150 /// Iterator to variable in previous scope that was declared just before 151 /// begin of this scope. 152 const_iterator Prev; 153 154public: 155 /// Constructs empty scope linked to previous scope in specified place. 156 LocalScope(const_iterator P) 157 : Vars() 158 , Prev(P) {} 159 160 /// Begin of scope in direction of CFG building (backwards). 161 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 162 163 void addVar(VarDecl* VD) { 164 Vars.push_back(VD); 165 } 166}; 167 168/// distance - Calculates distance from this to L. L must be reachable from this 169/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 170/// number of scopes between this and L. 171int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 172 int D = 0; 173 const_iterator F = *this; 174 while (F.Scope != L.Scope) { 175 assert (F != const_iterator() 176 && "L iterator is not reachable from F iterator."); 177 D += F.VarIter; 178 F = F.Scope->Prev; 179 } 180 D += F.VarIter - L.VarIter; 181 return D; 182} 183 184/// BlockScopePosPair - Structure for specifying position in CFG during its 185/// build process. It consists of CFGBlock that specifies position in CFG graph 186/// and LocalScope::const_iterator that specifies position in LocalScope graph. 187struct BlockScopePosPair { 188 BlockScopePosPair() {} 189 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 190 : Block(B), ScopePos(S) {} 191 192 CFGBlock* Block; 193 LocalScope::const_iterator ScopePos; 194}; 195 196/// CFGBuilder - This class implements CFG construction from an AST. 197/// The builder is stateful: an instance of the builder should be used to only 198/// construct a single CFG. 199/// 200/// Example usage: 201/// 202/// CFGBuilder builder; 203/// CFG* cfg = builder.BuildAST(stmt1); 204/// 205/// CFG construction is done via a recursive walk of an AST. We actually parse 206/// the AST in reverse order so that the successor of a basic block is 207/// constructed prior to its predecessor. This allows us to nicely capture 208/// implicit fall-throughs without extra basic blocks. 209/// 210class CFGBuilder { 211 typedef BlockScopePosPair JumpTarget; 212 typedef BlockScopePosPair JumpSource; 213 214 ASTContext *Context; 215 llvm::OwningPtr<CFG> cfg; 216 217 CFGBlock* Block; 218 CFGBlock* Succ; 219 JumpTarget ContinueJumpTarget; 220 JumpTarget BreakJumpTarget; 221 CFGBlock* SwitchTerminatedBlock; 222 CFGBlock* DefaultCaseBlock; 223 CFGBlock* TryTerminatedBlock; 224 225 // Current position in local scope. 226 LocalScope::const_iterator ScopePos; 227 228 // LabelMap records the mapping from Label expressions to their jump targets. 229 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 230 LabelMapTy LabelMap; 231 232 // A list of blocks that end with a "goto" that must be backpatched to their 233 // resolved targets upon completion of CFG construction. 234 typedef std::vector<JumpSource> BackpatchBlocksTy; 235 BackpatchBlocksTy BackpatchBlocks; 236 237 // A list of labels whose address has been taken (for indirect gotos). 238 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 239 LabelSetTy AddressTakenLabels; 240 241 bool badCFG; 242 CFG::BuildOptions BuildOpts; 243 244public: 245 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 246 Block(NULL), Succ(NULL), 247 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 248 TryTerminatedBlock(NULL), badCFG(false) {} 249 250 // buildCFG - Used by external clients to construct the CFG. 251 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 252 CFG::BuildOptions BO); 253 254private: 255 // Visitors to walk an AST and construct the CFG. 256 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 257 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 258 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 259 CFGBlock *VisitBreakStmt(BreakStmt *B); 260 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 261 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 262 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 263 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 264 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 265 CFGBlock *VisitCaseStmt(CaseStmt *C); 266 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 267 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 268 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 269 CFGBlock *VisitContinueStmt(ContinueStmt *C); 270 CFGBlock *VisitDeclStmt(DeclStmt *DS); 271 CFGBlock *VisitDeclSubExpr(Decl* D); 272 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 273 CFGBlock *VisitDoStmt(DoStmt *D); 274 CFGBlock *VisitForStmt(ForStmt *F); 275 CFGBlock *VisitGotoStmt(GotoStmt* G); 276 CFGBlock *VisitIfStmt(IfStmt *I); 277 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 278 CFGBlock *VisitLabelStmt(LabelStmt *L); 279 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 280 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 281 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 282 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 283 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 284 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 285 CFGBlock *VisitReturnStmt(ReturnStmt* R); 286 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 287 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 288 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 289 CFGBlock *VisitWhileStmt(WhileStmt *W); 290 291 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 292 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 293 CFGBlock *VisitChildren(Stmt* S); 294 295 // NYS == Not Yet Supported 296 CFGBlock* NYS() { 297 badCFG = true; 298 return Block; 299 } 300 301 void autoCreateBlock() { if (!Block) Block = createBlock(); } 302 CFGBlock *createBlock(bool add_successor = true); 303 304 CFGBlock *addStmt(Stmt *S) { 305 return Visit(S, AddStmtChoice::AlwaysAdd); 306 } 307 CFGBlock *addAutomaticObjDtors(LocalScope::const_iterator B, 308 LocalScope::const_iterator E, Stmt* S); 309 310 // Local scopes creation. 311 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 312 313 LocalScope* addLocalScopeForStmt(Stmt* S, LocalScope* Scope = NULL); 314 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 315 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 316 317 void addLocalScopeAndDtors(Stmt* S); 318 319 // Interface to CFGBlock - adding CFGElements. 320 void AppendStmt(CFGBlock *B, Stmt *S, 321 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 322 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 323 } 324 325 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 326 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 327 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 328 LocalScope::const_iterator E, Stmt* S); 329 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 330 LocalScope::const_iterator B, LocalScope::const_iterator E); 331 332 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 333 B->addSuccessor(S, cfg->getBumpVectorContext()); 334 } 335 336 /// TryResult - a class representing a variant over the values 337 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 338 /// and is used by the CFGBuilder to decide if a branch condition 339 /// can be decided up front during CFG construction. 340 class TryResult { 341 int X; 342 public: 343 TryResult(bool b) : X(b ? 1 : 0) {} 344 TryResult() : X(-1) {} 345 346 bool isTrue() const { return X == 1; } 347 bool isFalse() const { return X == 0; } 348 bool isKnown() const { return X >= 0; } 349 void negate() { 350 assert(isKnown()); 351 X ^= 0x1; 352 } 353 }; 354 355 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 356 /// if we can evaluate to a known value, otherwise return -1. 357 TryResult TryEvaluateBool(Expr *S) { 358 if (!BuildOpts.PruneTriviallyFalseEdges) 359 return TryResult(); 360 361 Expr::EvalResult Result; 362 if (!S->isTypeDependent() && !S->isValueDependent() && 363 S->Evaluate(Result, *Context) && Result.Val.isInt()) 364 return Result.Val.getInt().getBoolValue(); 365 366 return TryResult(); 367 } 368}; 369 370// FIXME: Add support for dependent-sized array types in C++? 371// Does it even make sense to build a CFG for an uninstantiated template? 372static VariableArrayType* FindVA(Type* t) { 373 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 374 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 375 if (vat->getSizeExpr()) 376 return vat; 377 378 t = vt->getElementType().getTypePtr(); 379 } 380 381 return 0; 382} 383 384/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 385/// arbitrary statement. Examples include a single expression or a function 386/// body (compound statement). The ownership of the returned CFG is 387/// transferred to the caller. If CFG construction fails, this method returns 388/// NULL. 389CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 390 CFG::BuildOptions BO) { 391 392 Context = C; 393 assert(cfg.get()); 394 if (!Statement) 395 return NULL; 396 397 BuildOpts = BO; 398 if (!C->getLangOptions().CPlusPlus) 399 BuildOpts.AddImplicitDtors = false; 400 401 // Create an empty block that will serve as the exit block for the CFG. Since 402 // this is the first block added to the CFG, it will be implicitly registered 403 // as the exit block. 404 Succ = createBlock(); 405 assert(Succ == &cfg->getExit()); 406 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 407 408 // Visit the statements and create the CFG. 409 CFGBlock *B = addStmt(Statement); 410 411 if (badCFG) 412 return NULL; 413 414 if (B) 415 Succ = B; 416 417 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 418 // FIXME: Add code for base initializers and member initializers. 419 (void)CD; 420 } 421 422 // Backpatch the gotos whose label -> block mappings we didn't know when we 423 // encountered them. 424 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 425 E = BackpatchBlocks.end(); I != E; ++I ) { 426 427 CFGBlock* B = I->Block; 428 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 429 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 430 431 // If there is no target for the goto, then we are looking at an 432 // incomplete AST. Handle this by not registering a successor. 433 if (LI == LabelMap.end()) continue; 434 435 JumpTarget JT = LI->second; 436 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 437 AddSuccessor(B, JT.Block); 438 } 439 440 // Add successors to the Indirect Goto Dispatch block (if we have one). 441 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 442 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 443 E = AddressTakenLabels.end(); I != E; ++I ) { 444 445 // Lookup the target block. 446 LabelMapTy::iterator LI = LabelMap.find(*I); 447 448 // If there is no target block that contains label, then we are looking 449 // at an incomplete AST. Handle this by not registering a successor. 450 if (LI == LabelMap.end()) continue; 451 452 AddSuccessor(B, LI->second.Block); 453 } 454 455 // Create an empty entry block that has no predecessors. 456 cfg->setEntry(createBlock()); 457 458 return cfg.take(); 459} 460 461/// createBlock - Used to lazily create blocks that are connected 462/// to the current (global) succcessor. 463CFGBlock* CFGBuilder::createBlock(bool add_successor) { 464 CFGBlock* B = cfg->createBlock(); 465 if (add_successor && Succ) 466 AddSuccessor(B, Succ); 467 return B; 468} 469 470/// addAutomaticObjDtors - Add to current block automatic objects destructors 471/// for objects in range of local scope positions. Use S as trigger statement 472/// for destructors. 473CFGBlock* CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 474 LocalScope::const_iterator E, Stmt* S) { 475 if (!BuildOpts.AddImplicitDtors) 476 return Block; 477 if (B == E) 478 return Block; 479 480 autoCreateBlock(); 481 appendAutomaticObjDtors(Block, B, E, S); 482 return Block; 483} 484 485/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 486/// way return valid LocalScope object. 487LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 488 if (!Scope) { 489 Scope = cfg->getAllocator().Allocate<LocalScope>(); 490 new (Scope) LocalScope(ScopePos); 491 } 492 return Scope; 493} 494 495/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 496/// that should create implicit scope (e.g. if/else substatements). Will reuse 497/// Scope if not NULL. 498LocalScope* CFGBuilder::addLocalScopeForStmt(Stmt* S, LocalScope* Scope) { 499 if (!BuildOpts.AddImplicitDtors) 500 return Scope; 501 502 // For compound statement we will be creating explicit scope. 503 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 504 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 505 ; BI != BE; ++BI) { 506 Stmt* SI = *BI; 507 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 508 SI = LS->getSubStmt(); 509 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 510 Scope = addLocalScopeForDeclStmt(DS, Scope); 511 } 512 return Scope; 513 } 514 515 // For any other statement scope will be implicit and as such will be 516 // interesting only for DeclStmt. 517 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 518 S = LS->getSubStmt(); 519 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 520 Scope = addLocalScopeForDeclStmt(DS, Scope); 521 return Scope; 522} 523 524/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 525/// reuse Scope if not NULL. 526LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 527 LocalScope* Scope) { 528 if (!BuildOpts.AddImplicitDtors) 529 return Scope; 530 531 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 532 ; DI != DE; ++DI) { 533 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 534 Scope = addLocalScopeForVarDecl(VD, Scope); 535 } 536 return Scope; 537} 538 539/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 540/// create add scope for automatic objects and temporary objects bound to 541/// const reference. Will reuse Scope if not NULL. 542LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 543 LocalScope* Scope) { 544 if (!BuildOpts.AddImplicitDtors) 545 return Scope; 546 547 // Check if variable is local. 548 switch (VD->getStorageClass()) { 549 case SC_None: 550 case SC_Auto: 551 case SC_Register: 552 break; 553 default: return Scope; 554 } 555 556 // Check for const references bound to temporary. Set type to pointee. 557 QualType QT = VD->getType(); 558 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 559 QT = RT->getPointeeType(); 560 if (!QT.isConstQualified()) 561 return Scope; 562 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 563 return Scope; 564 } 565 566 // Check if type is a C++ class with non-trivial destructor. 567 const RecordType* RT = QT.getTypePtr()->getAs<RecordType>(); 568 if (!RT || cast<CXXRecordDecl>(RT->getDecl())->hasTrivialDestructor()) 569 return Scope; 570 571 // Add the variable to scope 572 Scope = createOrReuseLocalScope(Scope); 573 Scope->addVar(VD); 574 ScopePos = Scope->begin(); 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, NULL); 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 // The block we were proccessing is now finished. Make it the successor 1139 // block. 1140 if (Block) { 1141 Succ = Block; 1142 if (badCFG) 1143 return 0; 1144 } 1145 1146 // Process the false branch. 1147 CFGBlock* ElseBlock = Succ; 1148 1149 if (Stmt* Else = I->getElse()) { 1150 SaveAndRestore<CFGBlock*> sv(Succ); 1151 1152 // NULL out Block so that the recursive call to Visit will 1153 // create a new basic block. 1154 Block = NULL; 1155 ElseBlock = addStmt(Else); 1156 1157 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1158 ElseBlock = sv.get(); 1159 else if (Block) { 1160 if (badCFG) 1161 return 0; 1162 } 1163 } 1164 1165 // Process the true branch. 1166 CFGBlock* ThenBlock; 1167 { 1168 Stmt* Then = I->getThen(); 1169 assert(Then); 1170 SaveAndRestore<CFGBlock*> sv(Succ); 1171 Block = NULL; 1172 ThenBlock = addStmt(Then); 1173 1174 if (!ThenBlock) { 1175 // We can reach here if the "then" body has all NullStmts. 1176 // Create an empty block so we can distinguish between true and false 1177 // branches in path-sensitive analyses. 1178 ThenBlock = createBlock(false); 1179 AddSuccessor(ThenBlock, sv.get()); 1180 } else if (Block) { 1181 if (badCFG) 1182 return 0; 1183 } 1184 } 1185 1186 // Now create a new block containing the if statement. 1187 Block = createBlock(false); 1188 1189 // Set the terminator of the new block to the If statement. 1190 Block->setTerminator(I); 1191 1192 // See if this is a known constant. 1193 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1194 1195 // Now add the successors. 1196 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1197 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1198 1199 // Add the condition as the last statement in the new block. This may create 1200 // new blocks as the condition may contain control-flow. Any newly created 1201 // blocks will be pointed to be "Block". 1202 Block = addStmt(I->getCond()); 1203 1204 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1205 // and the condition variable initialization to the CFG. 1206 if (VarDecl *VD = I->getConditionVariable()) { 1207 if (Expr *Init = VD->getInit()) { 1208 autoCreateBlock(); 1209 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1210 addStmt(Init); 1211 } 1212 } 1213 1214 return Block; 1215} 1216 1217 1218CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1219 // If we were in the middle of a block we stop processing that block. 1220 // 1221 // NOTE: If a "return" appears in the middle of a block, this means that the 1222 // code afterwards is DEAD (unreachable). We still keep a basic block 1223 // for that code; a simple "mark-and-sweep" from the entry block will be 1224 // able to report such dead blocks. 1225 1226 // Create the new block. 1227 Block = createBlock(false); 1228 1229 // The Exit block is the only successor. 1230 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1231 AddSuccessor(Block, &cfg->getExit()); 1232 1233 // Add the return statement to the block. This may create new blocks if R 1234 // contains control-flow (short-circuit operations). 1235 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1236} 1237 1238CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1239 // Get the block of the labeled statement. Add it to our map. 1240 addStmt(L->getSubStmt()); 1241 CFGBlock* LabelBlock = Block; 1242 1243 if (!LabelBlock) // This can happen when the body is empty, i.e. 1244 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1245 1246 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1247 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1248 1249 // Labels partition blocks, so this is the end of the basic block we were 1250 // processing (L is the block's label). Because this is label (and we have 1251 // already processed the substatement) there is no extra control-flow to worry 1252 // about. 1253 LabelBlock->setLabel(L); 1254 if (badCFG) 1255 return 0; 1256 1257 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1258 Block = NULL; 1259 1260 // This block is now the implicit successor of other blocks. 1261 Succ = LabelBlock; 1262 1263 return LabelBlock; 1264} 1265 1266CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1267 // Goto is a control-flow statement. Thus we stop processing the current 1268 // block and create a new one. 1269 1270 Block = createBlock(false); 1271 Block->setTerminator(G); 1272 1273 // If we already know the mapping to the label block add the successor now. 1274 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1275 1276 if (I == LabelMap.end()) 1277 // We will need to backpatch this block later. 1278 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1279 else { 1280 JumpTarget JT = I->second; 1281 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1282 AddSuccessor(Block, JT.Block); 1283 } 1284 1285 return Block; 1286} 1287 1288CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1289 CFGBlock* LoopSuccessor = NULL; 1290 1291 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1292 1293 // "for" is a control-flow statement. Thus we stop processing the current 1294 // block. 1295 if (Block) { 1296 if (badCFG) 1297 return 0; 1298 LoopSuccessor = Block; 1299 } else 1300 LoopSuccessor = Succ; 1301 1302 // Save the current value for the break targets. 1303 // All breaks should go to the code following the loop. 1304 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1305 BreakJumpTarget = JumpTarget(LoopSuccessor, LoopBeginScopePos); 1306 1307 // Because of short-circuit evaluation, the condition of the loop can span 1308 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1309 // evaluate the condition. 1310 CFGBlock* ExitConditionBlock = createBlock(false); 1311 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1312 1313 // Set the terminator for the "exit" condition block. 1314 ExitConditionBlock->setTerminator(F); 1315 1316 // Now add the actual condition to the condition block. Because the condition 1317 // itself may contain control-flow, new blocks may be created. 1318 if (Stmt* C = F->getCond()) { 1319 Block = ExitConditionBlock; 1320 EntryConditionBlock = addStmt(C); 1321 assert(Block == EntryConditionBlock || 1322 (Block == 0 && EntryConditionBlock == Succ)); 1323 1324 // If this block contains a condition variable, add both the condition 1325 // variable and initializer to the CFG. 1326 if (VarDecl *VD = F->getConditionVariable()) { 1327 if (Expr *Init = VD->getInit()) { 1328 autoCreateBlock(); 1329 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1330 EntryConditionBlock = addStmt(Init); 1331 assert(Block == EntryConditionBlock); 1332 } 1333 } 1334 1335 if (Block) { 1336 if (badCFG) 1337 return 0; 1338 } 1339 } 1340 1341 // The condition block is the implicit successor for the loop body as well as 1342 // any code above the loop. 1343 Succ = EntryConditionBlock; 1344 1345 // See if this is a known constant. 1346 TryResult KnownVal(true); 1347 1348 if (F->getCond()) 1349 KnownVal = TryEvaluateBool(F->getCond()); 1350 1351 // Now create the loop body. 1352 { 1353 assert(F->getBody()); 1354 1355 // Save the current values for Block, Succ, and continue targets. 1356 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1357 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1358 1359 // Create a new block to contain the (bottom) of the loop body. 1360 Block = NULL; 1361 1362 if (Stmt* I = F->getInc()) { 1363 // Generate increment code in its own basic block. This is the target of 1364 // continue statements. 1365 Succ = addStmt(I); 1366 } else { 1367 // No increment code. Create a special, empty, block that is used as the 1368 // target block for "looping back" to the start of the loop. 1369 assert(Succ == EntryConditionBlock); 1370 Succ = createBlock(); 1371 } 1372 1373 // Finish up the increment (or empty) block if it hasn't been already. 1374 if (Block) { 1375 assert(Block == Succ); 1376 if (badCFG) 1377 return 0; 1378 Block = 0; 1379 } 1380 1381 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1382 1383 // The starting block for the loop increment is the block that should 1384 // represent the 'loop target' for looping back to the start of the loop. 1385 ContinueJumpTarget.Block->setLoopTarget(F); 1386 1387 // Now populate the body block, and in the process create new blocks as we 1388 // walk the body of the loop. 1389 CFGBlock* BodyBlock = addStmt(F->getBody()); 1390 1391 if (!BodyBlock) 1392 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1393 else if (badCFG) 1394 return 0; 1395 1396 // This new body block is a successor to our "exit" condition block. 1397 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1398 } 1399 1400 // Link up the condition block with the code that follows the loop. (the 1401 // false branch). 1402 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1403 1404 // If the loop contains initialization, create a new block for those 1405 // statements. This block can also contain statements that precede the loop. 1406 if (Stmt* I = F->getInit()) { 1407 Block = createBlock(); 1408 return addStmt(I); 1409 } else { 1410 // There is no loop initialization. We are thus basically a while loop. 1411 // NULL out Block to force lazy block construction. 1412 Block = NULL; 1413 Succ = EntryConditionBlock; 1414 return EntryConditionBlock; 1415 } 1416} 1417 1418CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1419 if (asc.alwaysAdd()) { 1420 autoCreateBlock(); 1421 AppendStmt(Block, M, asc); 1422 } 1423 return Visit(M->getBase(), 1424 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1425 : AddStmtChoice::AsLValueNotAlwaysAdd); 1426} 1427 1428CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1429 // Objective-C fast enumeration 'for' statements: 1430 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1431 // 1432 // for ( Type newVariable in collection_expression ) { statements } 1433 // 1434 // becomes: 1435 // 1436 // prologue: 1437 // 1. collection_expression 1438 // T. jump to loop_entry 1439 // loop_entry: 1440 // 1. side-effects of element expression 1441 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1442 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1443 // TB: 1444 // statements 1445 // T. jump to loop_entry 1446 // FB: 1447 // what comes after 1448 // 1449 // and 1450 // 1451 // Type existingItem; 1452 // for ( existingItem in expression ) { statements } 1453 // 1454 // becomes: 1455 // 1456 // the same with newVariable replaced with existingItem; the binding works 1457 // the same except that for one ObjCForCollectionStmt::getElement() returns 1458 // a DeclStmt and the other returns a DeclRefExpr. 1459 // 1460 1461 CFGBlock* LoopSuccessor = 0; 1462 1463 if (Block) { 1464 if (badCFG) 1465 return 0; 1466 LoopSuccessor = Block; 1467 Block = 0; 1468 } else 1469 LoopSuccessor = Succ; 1470 1471 // Build the condition blocks. 1472 CFGBlock* ExitConditionBlock = createBlock(false); 1473 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1474 1475 // Set the terminator for the "exit" condition block. 1476 ExitConditionBlock->setTerminator(S); 1477 1478 // The last statement in the block should be the ObjCForCollectionStmt, which 1479 // performs the actual binding to 'element' and determines if there are any 1480 // more items in the collection. 1481 AppendStmt(ExitConditionBlock, S); 1482 Block = ExitConditionBlock; 1483 1484 // Walk the 'element' expression to see if there are any side-effects. We 1485 // generate new blocks as necesary. We DON'T add the statement by default to 1486 // the CFG unless it contains control-flow. 1487 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1488 if (Block) { 1489 if (badCFG) 1490 return 0; 1491 Block = 0; 1492 } 1493 1494 // The condition block is the implicit successor for the loop body as well as 1495 // any code above the loop. 1496 Succ = EntryConditionBlock; 1497 1498 // Now create the true branch. 1499 { 1500 // Save the current values for Succ, continue and break targets. 1501 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1502 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1503 save_break(BreakJumpTarget); 1504 1505 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1506 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1507 1508 CFGBlock* BodyBlock = addStmt(S->getBody()); 1509 1510 if (!BodyBlock) 1511 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1512 else if (Block) { 1513 if (badCFG) 1514 return 0; 1515 } 1516 1517 // This new body block is a successor to our "exit" condition block. 1518 AddSuccessor(ExitConditionBlock, BodyBlock); 1519 } 1520 1521 // Link up the condition block with the code that follows the loop. 1522 // (the false branch). 1523 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1524 1525 // Now create a prologue block to contain the collection expression. 1526 Block = createBlock(); 1527 return addStmt(S->getCollection()); 1528} 1529 1530CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1531 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1532 1533 // Inline the body. 1534 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1535 1536 // The sync body starts its own basic block. This makes it a little easier 1537 // for diagnostic clients. 1538 if (SyncBlock) { 1539 if (badCFG) 1540 return 0; 1541 1542 Block = 0; 1543 Succ = SyncBlock; 1544 } 1545 1546 // Add the @synchronized to the CFG. 1547 autoCreateBlock(); 1548 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1549 1550 // Inline the sync expression. 1551 return addStmt(S->getSynchExpr()); 1552} 1553 1554CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1555 // FIXME 1556 return NYS(); 1557} 1558 1559CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1560 CFGBlock* LoopSuccessor = NULL; 1561 1562 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1563 1564 // "while" is a control-flow statement. Thus we stop processing the current 1565 // block. 1566 if (Block) { 1567 if (badCFG) 1568 return 0; 1569 LoopSuccessor = Block; 1570 } else 1571 LoopSuccessor = Succ; 1572 1573 // Because of short-circuit evaluation, the condition of the loop can span 1574 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1575 // evaluate the condition. 1576 CFGBlock* ExitConditionBlock = createBlock(false); 1577 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1578 1579 // Set the terminator for the "exit" condition block. 1580 ExitConditionBlock->setTerminator(W); 1581 1582 // Now add the actual condition to the condition block. Because the condition 1583 // itself may contain control-flow, new blocks may be created. Thus we update 1584 // "Succ" after adding the condition. 1585 if (Stmt* C = W->getCond()) { 1586 Block = ExitConditionBlock; 1587 EntryConditionBlock = addStmt(C); 1588 assert(Block == EntryConditionBlock); 1589 1590 // If this block contains a condition variable, add both the condition 1591 // variable and initializer to the CFG. 1592 if (VarDecl *VD = W->getConditionVariable()) { 1593 if (Expr *Init = VD->getInit()) { 1594 autoCreateBlock(); 1595 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1596 EntryConditionBlock = addStmt(Init); 1597 assert(Block == EntryConditionBlock); 1598 } 1599 } 1600 1601 if (Block) { 1602 if (badCFG) 1603 return 0; 1604 } 1605 } 1606 1607 // The condition block is the implicit successor for the loop body as well as 1608 // any code above the loop. 1609 Succ = EntryConditionBlock; 1610 1611 // See if this is a known constant. 1612 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1613 1614 // Process the loop body. 1615 { 1616 assert(W->getBody()); 1617 1618 // Save the current values for Block, Succ, and continue and break targets 1619 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1620 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1621 save_break(BreakJumpTarget); 1622 1623 // Create an empty block to represent the transition block for looping back 1624 // to the head of the loop. 1625 Block = 0; 1626 assert(Succ == EntryConditionBlock); 1627 Succ = createBlock(); 1628 Succ->setLoopTarget(W); 1629 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1630 1631 // All breaks should go to the code following the loop. 1632 BreakJumpTarget = JumpTarget(LoopSuccessor, LoopBeginScopePos); 1633 1634 // NULL out Block to force lazy instantiation of blocks for the body. 1635 Block = NULL; 1636 1637 // Create the body. The returned block is the entry to the loop body. 1638 CFGBlock* BodyBlock = addStmt(W->getBody()); 1639 1640 if (!BodyBlock) 1641 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1642 else if (Block) { 1643 if (badCFG) 1644 return 0; 1645 } 1646 1647 // Add the loop body entry as a successor to the condition. 1648 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1649 } 1650 1651 // Link up the condition block with the code that follows the loop. (the 1652 // false branch). 1653 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1654 1655 // There can be no more statements in the condition block since we loop back 1656 // to this block. NULL out Block to force lazy creation of another block. 1657 Block = NULL; 1658 1659 // Return the condition block, which is the dominating block for the loop. 1660 Succ = EntryConditionBlock; 1661 return EntryConditionBlock; 1662} 1663 1664 1665CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1666 // FIXME: For now we pretend that @catch and the code it contains does not 1667 // exit. 1668 return Block; 1669} 1670 1671CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1672 // FIXME: This isn't complete. We basically treat @throw like a return 1673 // statement. 1674 1675 // If we were in the middle of a block we stop processing that block. 1676 if (badCFG) 1677 return 0; 1678 1679 // Create the new block. 1680 Block = createBlock(false); 1681 1682 // The Exit block is the only successor. 1683 AddSuccessor(Block, &cfg->getExit()); 1684 1685 // Add the statement to the block. This may create new blocks if S contains 1686 // control-flow (short-circuit operations). 1687 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1688} 1689 1690CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1691 // If we were in the middle of a block we stop processing that block. 1692 if (badCFG) 1693 return 0; 1694 1695 // Create the new block. 1696 Block = createBlock(false); 1697 1698 if (TryTerminatedBlock) 1699 // The current try statement is the only successor. 1700 AddSuccessor(Block, TryTerminatedBlock); 1701 else 1702 // otherwise the Exit block is the only successor. 1703 AddSuccessor(Block, &cfg->getExit()); 1704 1705 // Add the statement to the block. This may create new blocks if S contains 1706 // control-flow (short-circuit operations). 1707 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1708} 1709 1710CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1711 CFGBlock* LoopSuccessor = NULL; 1712 1713 // "do...while" is a control-flow statement. Thus we stop processing the 1714 // current block. 1715 if (Block) { 1716 if (badCFG) 1717 return 0; 1718 LoopSuccessor = Block; 1719 } else 1720 LoopSuccessor = Succ; 1721 1722 // Because of short-circuit evaluation, the condition of the loop can span 1723 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1724 // evaluate the condition. 1725 CFGBlock* ExitConditionBlock = createBlock(false); 1726 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1727 1728 // Set the terminator for the "exit" condition block. 1729 ExitConditionBlock->setTerminator(D); 1730 1731 // Now add the actual condition to the condition block. Because the condition 1732 // itself may contain control-flow, new blocks may be created. 1733 if (Stmt* C = D->getCond()) { 1734 Block = ExitConditionBlock; 1735 EntryConditionBlock = addStmt(C); 1736 if (Block) { 1737 if (badCFG) 1738 return 0; 1739 } 1740 } 1741 1742 // The condition block is the implicit successor for the loop body. 1743 Succ = EntryConditionBlock; 1744 1745 // See if this is a known constant. 1746 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1747 1748 // Process the loop body. 1749 CFGBlock* BodyBlock = NULL; 1750 { 1751 assert(D->getBody()); 1752 1753 // Save the current values for Block, Succ, and continue and break targets 1754 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1755 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1756 save_break(BreakJumpTarget); 1757 1758 // All continues within this loop should go to the condition block 1759 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1760 1761 // All breaks should go to the code following the loop. 1762 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1763 1764 // NULL out Block to force lazy instantiation of blocks for the body. 1765 Block = NULL; 1766 1767 // Create the body. The returned block is the entry to the loop body. 1768 BodyBlock = addStmt(D->getBody()); 1769 1770 if (!BodyBlock) 1771 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1772 else if (Block) { 1773 if (badCFG) 1774 return 0; 1775 } 1776 1777 if (!KnownVal.isFalse()) { 1778 // Add an intermediate block between the BodyBlock and the 1779 // ExitConditionBlock to represent the "loop back" transition. Create an 1780 // empty block to represent the transition block for looping back to the 1781 // head of the loop. 1782 // FIXME: Can we do this more efficiently without adding another block? 1783 Block = NULL; 1784 Succ = BodyBlock; 1785 CFGBlock *LoopBackBlock = createBlock(); 1786 LoopBackBlock->setLoopTarget(D); 1787 1788 // Add the loop body entry as a successor to the condition. 1789 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1790 } 1791 else 1792 AddSuccessor(ExitConditionBlock, NULL); 1793 } 1794 1795 // Link up the condition block with the code that follows the loop. 1796 // (the false branch). 1797 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1798 1799 // There can be no more statements in the body block(s) since we loop back to 1800 // the body. NULL out Block to force lazy creation of another block. 1801 Block = NULL; 1802 1803 // Return the loop body, which is the dominating block for the loop. 1804 Succ = BodyBlock; 1805 return BodyBlock; 1806} 1807 1808CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1809 // "continue" is a control-flow statement. Thus we stop processing the 1810 // current block. 1811 if (badCFG) 1812 return 0; 1813 1814 // Now create a new block that ends with the continue statement. 1815 Block = createBlock(false); 1816 Block->setTerminator(C); 1817 1818 // If there is no target for the continue, then we are looking at an 1819 // incomplete AST. This means the CFG cannot be constructed. 1820 if (ContinueJumpTarget.Block) { 1821 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1822 AddSuccessor(Block, ContinueJumpTarget.Block); 1823 } else 1824 badCFG = true; 1825 1826 return Block; 1827} 1828 1829CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1830 AddStmtChoice asc) { 1831 1832 if (asc.alwaysAdd()) { 1833 autoCreateBlock(); 1834 AppendStmt(Block, E); 1835 } 1836 1837 // VLA types have expressions that must be evaluated. 1838 if (E->isArgumentType()) { 1839 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1840 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1841 addStmt(VA->getSizeExpr()); 1842 } 1843 1844 return Block; 1845} 1846 1847/// VisitStmtExpr - Utility method to handle (nested) statement 1848/// expressions (a GCC extension). 1849CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 1850 if (asc.alwaysAdd()) { 1851 autoCreateBlock(); 1852 AppendStmt(Block, SE); 1853 } 1854 return VisitCompoundStmt(SE->getSubStmt()); 1855} 1856 1857CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1858 // "switch" is a control-flow statement. Thus we stop processing the current 1859 // block. 1860 CFGBlock* SwitchSuccessor = NULL; 1861 1862 if (Block) { 1863 if (badCFG) 1864 return 0; 1865 SwitchSuccessor = Block; 1866 } else SwitchSuccessor = Succ; 1867 1868 // Save the current "switch" context. 1869 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1870 save_default(DefaultCaseBlock); 1871 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1872 1873 // Set the "default" case to be the block after the switch statement. If the 1874 // switch statement contains a "default:", this value will be overwritten with 1875 // the block for that code. 1876 DefaultCaseBlock = SwitchSuccessor; 1877 1878 // Create a new block that will contain the switch statement. 1879 SwitchTerminatedBlock = createBlock(false); 1880 1881 // Now process the switch body. The code after the switch is the implicit 1882 // successor. 1883 Succ = SwitchSuccessor; 1884 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 1885 1886 // When visiting the body, the case statements should automatically get linked 1887 // up to the switch. We also don't keep a pointer to the body, since all 1888 // control-flow from the switch goes to case/default statements. 1889 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 1890 Block = NULL; 1891 addStmt(Terminator->getBody()); 1892 if (Block) { 1893 if (badCFG) 1894 return 0; 1895 } 1896 1897 // If we have no "default:" case, the default transition is to the code 1898 // following the switch body. 1899 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1900 1901 // Add the terminator and condition in the switch block. 1902 SwitchTerminatedBlock->setTerminator(Terminator); 1903 assert(Terminator->getCond() && "switch condition must be non-NULL"); 1904 Block = SwitchTerminatedBlock; 1905 Block = addStmt(Terminator->getCond()); 1906 1907 // Finally, if the SwitchStmt contains a condition variable, add both the 1908 // SwitchStmt and the condition variable initialization to the CFG. 1909 if (VarDecl *VD = Terminator->getConditionVariable()) { 1910 if (Expr *Init = VD->getInit()) { 1911 autoCreateBlock(); 1912 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 1913 addStmt(Init); 1914 } 1915 } 1916 1917 return Block; 1918} 1919 1920CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1921 // CaseStmts are essentially labels, so they are the first statement in a 1922 // block. 1923 CFGBlock *TopBlock = 0, *LastBlock = 0; 1924 1925 if (Stmt *Sub = CS->getSubStmt()) { 1926 // For deeply nested chains of CaseStmts, instead of doing a recursion 1927 // (which can blow out the stack), manually unroll and create blocks 1928 // along the way. 1929 while (isa<CaseStmt>(Sub)) { 1930 CFGBlock *CurrentBlock = createBlock(false); 1931 CurrentBlock->setLabel(CS); 1932 1933 if (TopBlock) 1934 AddSuccessor(LastBlock, CurrentBlock); 1935 else 1936 TopBlock = CurrentBlock; 1937 1938 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 1939 LastBlock = CurrentBlock; 1940 1941 CS = cast<CaseStmt>(Sub); 1942 Sub = CS->getSubStmt(); 1943 } 1944 1945 addStmt(Sub); 1946 } 1947 1948 CFGBlock* CaseBlock = Block; 1949 if (!CaseBlock) 1950 CaseBlock = createBlock(); 1951 1952 // Cases statements partition blocks, so this is the top of the basic block we 1953 // were processing (the "case XXX:" is the label). 1954 CaseBlock->setLabel(CS); 1955 1956 if (badCFG) 1957 return 0; 1958 1959 // Add this block to the list of successors for the block with the switch 1960 // statement. 1961 assert(SwitchTerminatedBlock); 1962 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 1963 1964 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1965 Block = NULL; 1966 1967 if (TopBlock) { 1968 AddSuccessor(LastBlock, CaseBlock); 1969 Succ = TopBlock; 1970 } 1971 else { 1972 // This block is now the implicit successor of other blocks. 1973 Succ = CaseBlock; 1974 } 1975 1976 return Succ; 1977} 1978 1979CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 1980 if (Terminator->getSubStmt()) 1981 addStmt(Terminator->getSubStmt()); 1982 1983 DefaultCaseBlock = Block; 1984 1985 if (!DefaultCaseBlock) 1986 DefaultCaseBlock = createBlock(); 1987 1988 // Default statements partition blocks, so this is the top of the basic block 1989 // we were processing (the "default:" is the label). 1990 DefaultCaseBlock->setLabel(Terminator); 1991 1992 if (badCFG) 1993 return 0; 1994 1995 // Unlike case statements, we don't add the default block to the successors 1996 // for the switch statement immediately. This is done when we finish 1997 // processing the switch statement. This allows for the default case 1998 // (including a fall-through to the code after the switch statement) to always 1999 // be the last successor of a switch-terminated block. 2000 2001 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2002 Block = NULL; 2003 2004 // This block is now the implicit successor of other blocks. 2005 Succ = DefaultCaseBlock; 2006 2007 return DefaultCaseBlock; 2008} 2009 2010CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2011 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2012 // current block. 2013 CFGBlock* TrySuccessor = NULL; 2014 2015 if (Block) { 2016 if (badCFG) 2017 return 0; 2018 TrySuccessor = Block; 2019 } else TrySuccessor = Succ; 2020 2021 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2022 2023 // Create a new block that will contain the try statement. 2024 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2025 // Add the terminator in the try block. 2026 NewTryTerminatedBlock->setTerminator(Terminator); 2027 2028 bool HasCatchAll = false; 2029 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2030 // The code after the try is the implicit successor. 2031 Succ = TrySuccessor; 2032 CXXCatchStmt *CS = Terminator->getHandler(h); 2033 if (CS->getExceptionDecl() == 0) { 2034 HasCatchAll = true; 2035 } 2036 Block = NULL; 2037 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2038 if (CatchBlock == 0) 2039 return 0; 2040 // Add this block to the list of successors for the block with the try 2041 // statement. 2042 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2043 } 2044 if (!HasCatchAll) { 2045 if (PrevTryTerminatedBlock) 2046 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2047 else 2048 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2049 } 2050 2051 // The code after the try is the implicit successor. 2052 Succ = TrySuccessor; 2053 2054 // Save the current "try" context. 2055 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2056 TryTerminatedBlock = NewTryTerminatedBlock; 2057 2058 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2059 Block = NULL; 2060 Block = addStmt(Terminator->getTryBlock()); 2061 return Block; 2062} 2063 2064CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2065 // CXXCatchStmt are treated like labels, so they are the first statement in a 2066 // block. 2067 2068 if (CS->getHandlerBlock()) 2069 addStmt(CS->getHandlerBlock()); 2070 2071 CFGBlock* CatchBlock = Block; 2072 if (!CatchBlock) 2073 CatchBlock = createBlock(); 2074 2075 CatchBlock->setLabel(CS); 2076 2077 if (badCFG) 2078 return 0; 2079 2080 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2081 Block = NULL; 2082 2083 return CatchBlock; 2084} 2085 2086CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2087 AddStmtChoice asc) { 2088 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2089 : AddStmtChoice::AlwaysAdd; 2090 autoCreateBlock(); 2091 AppendStmt(Block, C, AddStmtChoice(K)); 2092 return VisitChildren(C); 2093} 2094 2095CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2096 // Lazily create the indirect-goto dispatch block if there isn't one already. 2097 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2098 2099 if (!IBlock) { 2100 IBlock = createBlock(false); 2101 cfg->setIndirectGotoBlock(IBlock); 2102 } 2103 2104 // IndirectGoto is a control-flow statement. Thus we stop processing the 2105 // current block and create a new one. 2106 if (badCFG) 2107 return 0; 2108 2109 Block = createBlock(false); 2110 Block->setTerminator(I); 2111 AddSuccessor(Block, IBlock); 2112 return addStmt(I->getTarget()); 2113} 2114 2115} // end anonymous namespace 2116 2117/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2118/// no successors or predecessors. If this is the first block created in the 2119/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2120CFGBlock* CFG::createBlock() { 2121 bool first_block = begin() == end(); 2122 2123 // Create the block. 2124 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2125 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2126 Blocks.push_back(Mem, BlkBVC); 2127 2128 // If this is the first block, set it as the Entry and Exit. 2129 if (first_block) 2130 Entry = Exit = &back(); 2131 2132 // Return the block. 2133 return &back(); 2134} 2135 2136/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2137/// CFG is returned to the caller. 2138CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2139 BuildOptions BO) { 2140 CFGBuilder Builder; 2141 return Builder.buildCFG(D, Statement, C, BO); 2142} 2143 2144//===----------------------------------------------------------------------===// 2145// CFG: Queries for BlkExprs. 2146//===----------------------------------------------------------------------===// 2147 2148namespace { 2149 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2150} 2151 2152static void FindSubExprAssignments(Stmt *S, 2153 llvm::SmallPtrSet<Expr*,50>& Set) { 2154 if (!S) 2155 return; 2156 2157 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2158 Stmt *child = *I; 2159 if (!child) 2160 continue; 2161 2162 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2163 if (B->isAssignmentOp()) Set.insert(B); 2164 2165 FindSubExprAssignments(child, Set); 2166 } 2167} 2168 2169static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2170 BlkExprMapTy* M = new BlkExprMapTy(); 2171 2172 // Look for assignments that are used as subexpressions. These are the only 2173 // assignments that we want to *possibly* register as a block-level 2174 // expression. Basically, if an assignment occurs both in a subexpression and 2175 // at the block-level, it is a block-level expression. 2176 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2177 2178 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2179 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2180 if (CFGStmt S = BI->getAs<CFGStmt>()) 2181 FindSubExprAssignments(S, SubExprAssignments); 2182 2183 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2184 2185 // Iterate over the statements again on identify the Expr* and Stmt* at the 2186 // block-level that are block-level expressions. 2187 2188 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2189 CFGStmt CS = BI->getAs<CFGStmt>(); 2190 if (!CS.isValid()) 2191 continue; 2192 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2193 2194 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2195 // Assignment expressions that are not nested within another 2196 // expression are really "statements" whose value is never used by 2197 // another expression. 2198 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2199 continue; 2200 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2201 // Special handling for statement expressions. The last statement in 2202 // the statement expression is also a block-level expr. 2203 const CompoundStmt* C = Terminator->getSubStmt(); 2204 if (!C->body_empty()) { 2205 unsigned x = M->size(); 2206 (*M)[C->body_back()] = x; 2207 } 2208 } 2209 2210 unsigned x = M->size(); 2211 (*M)[Exp] = x; 2212 } 2213 } 2214 2215 // Look at terminators. The condition is a block-level expression. 2216 2217 Stmt* S = (*I)->getTerminatorCondition(); 2218 2219 if (S && M->find(S) == M->end()) { 2220 unsigned x = M->size(); 2221 (*M)[S] = x; 2222 } 2223 } 2224 2225 return M; 2226} 2227 2228CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2229 assert(S != NULL); 2230 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2231 2232 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2233 BlkExprMapTy::iterator I = M->find(S); 2234 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2235} 2236 2237unsigned CFG::getNumBlkExprs() { 2238 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2239 return M->size(); 2240 else { 2241 // We assume callers interested in the number of BlkExprs will want 2242 // the map constructed if it doesn't already exist. 2243 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2244 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2245 } 2246} 2247 2248//===----------------------------------------------------------------------===// 2249// Filtered walking of the CFG. 2250//===----------------------------------------------------------------------===// 2251 2252bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2253 const CFGBlock *From, const CFGBlock *To) { 2254 2255 if (F.IgnoreDefaultsWithCoveredEnums) { 2256 // If the 'To' has no label or is labeled but the label isn't a 2257 // CaseStmt then filter this edge. 2258 if (const SwitchStmt *S = 2259 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2260 if (S->isAllEnumCasesCovered()) { 2261 const Stmt *L = To->getLabel(); 2262 if (!L || !isa<CaseStmt>(L)) 2263 return true; 2264 } 2265 } 2266 } 2267 2268 return false; 2269} 2270 2271//===----------------------------------------------------------------------===// 2272// Cleanup: CFG dstor. 2273//===----------------------------------------------------------------------===// 2274 2275CFG::~CFG() { 2276 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2277} 2278 2279//===----------------------------------------------------------------------===// 2280// CFG pretty printing 2281//===----------------------------------------------------------------------===// 2282 2283namespace { 2284 2285class StmtPrinterHelper : public PrinterHelper { 2286 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2287 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2288 StmtMapTy StmtMap; 2289 DeclMapTy DeclMap; 2290 signed CurrentBlock; 2291 unsigned CurrentStmt; 2292 const LangOptions &LangOpts; 2293public: 2294 2295 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2296 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2297 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2298 unsigned j = 1; 2299 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2300 BI != BEnd; ++BI, ++j ) { 2301 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2302 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2303 StmtMap[SE] = P; 2304 2305 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2306 DeclMap[DS->getSingleDecl()] = P; 2307 2308 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2309 if (VarDecl* VD = IS->getConditionVariable()) 2310 DeclMap[VD] = P; 2311 2312 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2313 if (VarDecl* VD = FS->getConditionVariable()) 2314 DeclMap[VD] = P; 2315 2316 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2317 if (VarDecl* VD = WS->getConditionVariable()) 2318 DeclMap[VD] = P; 2319 2320 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2321 if (VarDecl* VD = SS->getConditionVariable()) 2322 DeclMap[VD] = P; 2323 2324 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2325 if (VarDecl* VD = CS->getExceptionDecl()) 2326 DeclMap[VD] = P; 2327 } 2328 } 2329 } 2330 } 2331 } 2332 2333 virtual ~StmtPrinterHelper() {} 2334 2335 const LangOptions &getLangOpts() const { return LangOpts; } 2336 void setBlockID(signed i) { CurrentBlock = i; } 2337 void setStmtID(unsigned i) { CurrentStmt = i; } 2338 2339 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2340 StmtMapTy::iterator I = StmtMap.find(S); 2341 2342 if (I == StmtMap.end()) 2343 return false; 2344 2345 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2346 && I->second.second == CurrentStmt) { 2347 return false; 2348 } 2349 2350 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2351 return true; 2352 } 2353 2354 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2355 DeclMapTy::iterator I = DeclMap.find(D); 2356 2357 if (I == DeclMap.end()) 2358 return false; 2359 2360 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2361 && I->second.second == CurrentStmt) { 2362 return false; 2363 } 2364 2365 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2366 return true; 2367 } 2368}; 2369} // end anonymous namespace 2370 2371 2372namespace { 2373class CFGBlockTerminatorPrint 2374 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2375 2376 llvm::raw_ostream& OS; 2377 StmtPrinterHelper* Helper; 2378 PrintingPolicy Policy; 2379public: 2380 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2381 const PrintingPolicy &Policy) 2382 : OS(os), Helper(helper), Policy(Policy) {} 2383 2384 void VisitIfStmt(IfStmt* I) { 2385 OS << "if "; 2386 I->getCond()->printPretty(OS,Helper,Policy); 2387 } 2388 2389 // Default case. 2390 void VisitStmt(Stmt* Terminator) { 2391 Terminator->printPretty(OS, Helper, Policy); 2392 } 2393 2394 void VisitForStmt(ForStmt* F) { 2395 OS << "for (" ; 2396 if (F->getInit()) 2397 OS << "..."; 2398 OS << "; "; 2399 if (Stmt* C = F->getCond()) 2400 C->printPretty(OS, Helper, Policy); 2401 OS << "; "; 2402 if (F->getInc()) 2403 OS << "..."; 2404 OS << ")"; 2405 } 2406 2407 void VisitWhileStmt(WhileStmt* W) { 2408 OS << "while " ; 2409 if (Stmt* C = W->getCond()) 2410 C->printPretty(OS, Helper, Policy); 2411 } 2412 2413 void VisitDoStmt(DoStmt* D) { 2414 OS << "do ... while "; 2415 if (Stmt* C = D->getCond()) 2416 C->printPretty(OS, Helper, Policy); 2417 } 2418 2419 void VisitSwitchStmt(SwitchStmt* Terminator) { 2420 OS << "switch "; 2421 Terminator->getCond()->printPretty(OS, Helper, Policy); 2422 } 2423 2424 void VisitCXXTryStmt(CXXTryStmt* CS) { 2425 OS << "try ..."; 2426 } 2427 2428 void VisitConditionalOperator(ConditionalOperator* C) { 2429 C->getCond()->printPretty(OS, Helper, Policy); 2430 OS << " ? ... : ..."; 2431 } 2432 2433 void VisitChooseExpr(ChooseExpr* C) { 2434 OS << "__builtin_choose_expr( "; 2435 C->getCond()->printPretty(OS, Helper, Policy); 2436 OS << " )"; 2437 } 2438 2439 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2440 OS << "goto *"; 2441 I->getTarget()->printPretty(OS, Helper, Policy); 2442 } 2443 2444 void VisitBinaryOperator(BinaryOperator* B) { 2445 if (!B->isLogicalOp()) { 2446 VisitExpr(B); 2447 return; 2448 } 2449 2450 B->getLHS()->printPretty(OS, Helper, Policy); 2451 2452 switch (B->getOpcode()) { 2453 case BO_LOr: 2454 OS << " || ..."; 2455 return; 2456 case BO_LAnd: 2457 OS << " && ..."; 2458 return; 2459 default: 2460 assert(false && "Invalid logical operator."); 2461 } 2462 } 2463 2464 void VisitExpr(Expr* E) { 2465 E->printPretty(OS, Helper, Policy); 2466 } 2467}; 2468} // end anonymous namespace 2469 2470static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2471 const CFGElement &E) { 2472 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2473 Stmt *S = CS; 2474 2475 if (Helper) { 2476 2477 // special printing for statement-expressions. 2478 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2479 CompoundStmt* Sub = SE->getSubStmt(); 2480 2481 if (Sub->child_begin() != Sub->child_end()) { 2482 OS << "({ ... ; "; 2483 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2484 OS << " })\n"; 2485 return; 2486 } 2487 } 2488 // special printing for comma expressions. 2489 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2490 if (B->getOpcode() == BO_Comma) { 2491 OS << "... , "; 2492 Helper->handledStmt(B->getRHS(),OS); 2493 OS << '\n'; 2494 return; 2495 } 2496 } 2497 } 2498 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2499 2500 if (isa<CXXOperatorCallExpr>(S)) { 2501 OS << " (OperatorCall)"; 2502 } 2503 else if (isa<CXXBindTemporaryExpr>(S)) { 2504 OS << " (BindTemporary)"; 2505 } 2506 2507 // Expressions need a newline. 2508 if (isa<Expr>(S)) 2509 OS << '\n'; 2510 2511 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2512 CXXBaseOrMemberInitializer* I = IE; 2513 if (I->isBaseInitializer()) 2514 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2515 else OS << I->getMember()->getName(); 2516 2517 OS << "("; 2518 if (Expr* IE = I->getInit()) 2519 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2520 OS << ")"; 2521 2522 if (I->isBaseInitializer()) 2523 OS << " (Base initializer)\n"; 2524 else OS << " (Member initializer)\n"; 2525 2526 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2527 VarDecl* VD = DE.getVarDecl(); 2528 Helper->handleDecl(VD, OS); 2529 2530 Type* T = VD->getType().getTypePtr(); 2531 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2532 T = RT->getPointeeType().getTypePtr(); 2533 2534 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2535 OS << " (Implicit destructor)\n"; 2536 } 2537 } 2538 2539static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2540 const CFGBlock& B, 2541 StmtPrinterHelper* Helper, bool print_edges) { 2542 2543 if (Helper) Helper->setBlockID(B.getBlockID()); 2544 2545 // Print the header. 2546 OS << "\n [ B" << B.getBlockID(); 2547 2548 if (&B == &cfg->getEntry()) 2549 OS << " (ENTRY) ]\n"; 2550 else if (&B == &cfg->getExit()) 2551 OS << " (EXIT) ]\n"; 2552 else if (&B == cfg->getIndirectGotoBlock()) 2553 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2554 else 2555 OS << " ]\n"; 2556 2557 // Print the label of this block. 2558 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2559 2560 if (print_edges) 2561 OS << " "; 2562 2563 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2564 OS << L->getName(); 2565 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2566 OS << "case "; 2567 C->getLHS()->printPretty(OS, Helper, 2568 PrintingPolicy(Helper->getLangOpts())); 2569 if (C->getRHS()) { 2570 OS << " ... "; 2571 C->getRHS()->printPretty(OS, Helper, 2572 PrintingPolicy(Helper->getLangOpts())); 2573 } 2574 } else if (isa<DefaultStmt>(Label)) 2575 OS << "default"; 2576 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2577 OS << "catch ("; 2578 if (CS->getExceptionDecl()) 2579 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2580 0); 2581 else 2582 OS << "..."; 2583 OS << ")"; 2584 2585 } else 2586 assert(false && "Invalid label statement in CFGBlock."); 2587 2588 OS << ":\n"; 2589 } 2590 2591 // Iterate through the statements in the block and print them. 2592 unsigned j = 1; 2593 2594 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2595 I != E ; ++I, ++j ) { 2596 2597 // Print the statement # in the basic block and the statement itself. 2598 if (print_edges) 2599 OS << " "; 2600 2601 OS << llvm::format("%3d", j) << ": "; 2602 2603 if (Helper) 2604 Helper->setStmtID(j); 2605 2606 print_elem(OS,Helper,*I); 2607 } 2608 2609 // Print the terminator of this block. 2610 if (B.getTerminator()) { 2611 if (print_edges) 2612 OS << " "; 2613 2614 OS << " T: "; 2615 2616 if (Helper) Helper->setBlockID(-1); 2617 2618 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2619 PrintingPolicy(Helper->getLangOpts())); 2620 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2621 OS << '\n'; 2622 } 2623 2624 if (print_edges) { 2625 // Print the predecessors of this block. 2626 OS << " Predecessors (" << B.pred_size() << "):"; 2627 unsigned i = 0; 2628 2629 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2630 I != E; ++I, ++i) { 2631 2632 if (i == 8 || (i-8) == 0) 2633 OS << "\n "; 2634 2635 OS << " B" << (*I)->getBlockID(); 2636 } 2637 2638 OS << '\n'; 2639 2640 // Print the successors of this block. 2641 OS << " Successors (" << B.succ_size() << "):"; 2642 i = 0; 2643 2644 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2645 I != E; ++I, ++i) { 2646 2647 if (i == 8 || (i-8) % 10 == 0) 2648 OS << "\n "; 2649 2650 if (*I) 2651 OS << " B" << (*I)->getBlockID(); 2652 else 2653 OS << " NULL"; 2654 } 2655 2656 OS << '\n'; 2657 } 2658} 2659 2660 2661/// dump - A simple pretty printer of a CFG that outputs to stderr. 2662void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2663 2664/// print - A simple pretty printer of a CFG that outputs to an ostream. 2665void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2666 StmtPrinterHelper Helper(this, LO); 2667 2668 // Print the entry block. 2669 print_block(OS, this, getEntry(), &Helper, true); 2670 2671 // Iterate through the CFGBlocks and print them one by one. 2672 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2673 // Skip the entry block, because we already printed it. 2674 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2675 continue; 2676 2677 print_block(OS, this, **I, &Helper, true); 2678 } 2679 2680 // Print the exit block. 2681 print_block(OS, this, getExit(), &Helper, true); 2682 OS.flush(); 2683} 2684 2685/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2686void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2687 print(llvm::errs(), cfg, LO); 2688} 2689 2690/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2691/// Generally this will only be called from CFG::print. 2692void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2693 const LangOptions &LO) const { 2694 StmtPrinterHelper Helper(cfg, LO); 2695 print_block(OS, cfg, *this, &Helper, true); 2696} 2697 2698/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2699void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2700 const LangOptions &LO) const { 2701 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2702 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2703} 2704 2705Stmt* CFGBlock::getTerminatorCondition() { 2706 2707 if (!Terminator) 2708 return NULL; 2709 2710 Expr* E = NULL; 2711 2712 switch (Terminator->getStmtClass()) { 2713 default: 2714 break; 2715 2716 case Stmt::ForStmtClass: 2717 E = cast<ForStmt>(Terminator)->getCond(); 2718 break; 2719 2720 case Stmt::WhileStmtClass: 2721 E = cast<WhileStmt>(Terminator)->getCond(); 2722 break; 2723 2724 case Stmt::DoStmtClass: 2725 E = cast<DoStmt>(Terminator)->getCond(); 2726 break; 2727 2728 case Stmt::IfStmtClass: 2729 E = cast<IfStmt>(Terminator)->getCond(); 2730 break; 2731 2732 case Stmt::ChooseExprClass: 2733 E = cast<ChooseExpr>(Terminator)->getCond(); 2734 break; 2735 2736 case Stmt::IndirectGotoStmtClass: 2737 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2738 break; 2739 2740 case Stmt::SwitchStmtClass: 2741 E = cast<SwitchStmt>(Terminator)->getCond(); 2742 break; 2743 2744 case Stmt::ConditionalOperatorClass: 2745 E = cast<ConditionalOperator>(Terminator)->getCond(); 2746 break; 2747 2748 case Stmt::BinaryOperatorClass: // '&&' and '||' 2749 E = cast<BinaryOperator>(Terminator)->getLHS(); 2750 break; 2751 2752 case Stmt::ObjCForCollectionStmtClass: 2753 return Terminator; 2754 } 2755 2756 return E ? E->IgnoreParens() : NULL; 2757} 2758 2759bool CFGBlock::hasBinaryBranchTerminator() const { 2760 2761 if (!Terminator) 2762 return false; 2763 2764 Expr* E = NULL; 2765 2766 switch (Terminator->getStmtClass()) { 2767 default: 2768 return false; 2769 2770 case Stmt::ForStmtClass: 2771 case Stmt::WhileStmtClass: 2772 case Stmt::DoStmtClass: 2773 case Stmt::IfStmtClass: 2774 case Stmt::ChooseExprClass: 2775 case Stmt::ConditionalOperatorClass: 2776 case Stmt::BinaryOperatorClass: 2777 return true; 2778 } 2779 2780 return E ? E->IgnoreParens() : NULL; 2781} 2782 2783 2784//===----------------------------------------------------------------------===// 2785// CFG Graphviz Visualization 2786//===----------------------------------------------------------------------===// 2787 2788 2789#ifndef NDEBUG 2790static StmtPrinterHelper* GraphHelper; 2791#endif 2792 2793void CFG::viewCFG(const LangOptions &LO) const { 2794#ifndef NDEBUG 2795 StmtPrinterHelper H(this, LO); 2796 GraphHelper = &H; 2797 llvm::ViewGraph(this,"CFG"); 2798 GraphHelper = NULL; 2799#endif 2800} 2801 2802namespace llvm { 2803template<> 2804struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2805 2806 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2807 2808 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 2809 2810#ifndef NDEBUG 2811 std::string OutSStr; 2812 llvm::raw_string_ostream Out(OutSStr); 2813 print_block(Out,Graph, *Node, GraphHelper, false); 2814 std::string& OutStr = Out.str(); 2815 2816 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2817 2818 // Process string output to make it nicer... 2819 for (unsigned i = 0; i != OutStr.length(); ++i) 2820 if (OutStr[i] == '\n') { // Left justify 2821 OutStr[i] = '\\'; 2822 OutStr.insert(OutStr.begin()+i+1, 'l'); 2823 } 2824 2825 return OutStr; 2826#else 2827 return ""; 2828#endif 2829 } 2830}; 2831} // end namespace llvm 2832