CFG.cpp revision d6294f50b2c2636026cb4b0ea47ec4a4b59af6ff
1cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project// 305436638acc7c010349a69c3395f1a57c642dc62Ying Wang// The LLVM Compiler Infrastructure 4cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project// 505436638acc7c010349a69c3395f1a57c642dc62Ying Wang// This file is distributed under the University of Illinois Open Source 6cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project// License. See LICENSE.TXT for details. 705436638acc7c010349a69c3395f1a57c642dc62Ying Wang// 805436638acc7c010349a69c3395f1a57c642dc62Ying Wang//===----------------------------------------------------------------------===// 9cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project// 10cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project// This file defines the CFG and CFGBuilder classes for representing and 11cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project// building Control-Flow Graphs (CFGs) from ASTs. 12cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project// 13cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project//===----------------------------------------------------------------------===// 14cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project 15cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project#include "clang/Analysis/Support/SaveAndRestore.h" 1605436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "clang/Analysis/CFG.h" 17cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project#include "clang/AST/DeclCXX.h" 1805436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "clang/AST/StmtVisitor.h" 1905436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "clang/AST/PrettyPrinter.h" 20cea198a11f15a2eb071d98491ca9a8bc8cebfbc4The Android Open Source Project#include "llvm/Support/GraphWriter.h" 2105436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "llvm/Support/Allocator.h" 2205436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "llvm/Support/Format.h" 2305436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "llvm/ADT/DenseMap.h" 2405436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "llvm/ADT/SmallPtrSet.h" 2505436638acc7c010349a69c3395f1a57c642dc62Ying Wang#include "llvm/ADT/OwningPtr.h" 2605436638acc7c010349a69c3395f1a57c642dc62Ying Wang 2705436638acc7c010349a69c3395f1a57c642dc62Ying Wangusing namespace clang; 2805436638acc7c010349a69c3395f1a57c642dc62Ying Wang 2905436638acc7c010349a69c3395f1a57c642dc62Ying Wangnamespace { 3005436638acc7c010349a69c3395f1a57c642dc62Ying Wang 3105436638acc7c010349a69c3395f1a57c642dc62Ying Wangstatic SourceLocation GetEndLoc(Decl* D) { 3205436638acc7c010349a69c3395f1a57c642dc62Ying Wang if (VarDecl* VD = dyn_cast<VarDecl>(D)) 3305436638acc7c010349a69c3395f1a57c642dc62Ying Wang if (Expr* Ex = VD->getInit()) 3405436638acc7c010349a69c3395f1a57c642dc62Ying Wang return Ex->getSourceRange().getEnd(); 3505436638acc7c010349a69c3395f1a57c642dc62Ying Wang 3605436638acc7c010349a69c3395f1a57c642dc62Ying Wang return D->getLocation(); 3705436638acc7c010349a69c3395f1a57c642dc62Ying Wang} 3805436638acc7c010349a69c3395f1a57c642dc62Ying Wang 3905436638acc7c010349a69c3395f1a57c642dc62Ying Wangclass AddStmtChoice { 4005436638acc7c010349a69c3395f1a57c642dc62Ying Wangpublic: 4105436638acc7c010349a69c3395f1a57c642dc62Ying Wang enum Kind { NotAlwaysAdd = 0, 4205436638acc7c010349a69c3395f1a57c642dc62Ying Wang AlwaysAdd = 1, 4305436638acc7c010349a69c3395f1a57c642dc62Ying Wang AsLValueNotAlwaysAdd = 2, 4405436638acc7c010349a69c3395f1a57c642dc62Ying Wang AlwaysAddAsLValue = 3 }; 4505436638acc7c010349a69c3395f1a57c642dc62Ying Wang 4605436638acc7c010349a69c3395f1a57c642dc62Ying Wang AddStmtChoice(Kind kind) : k(kind) {} 47 48 bool alwaysAdd() const { return (unsigned)k & 0x1; } 49 bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } 50 51private: 52 Kind k; 53}; 54 55/// LocalScope - Node in tree of local scopes created for C++ implicit 56/// destructor calls generation. It contains list of automatic variables 57/// declared in the scope and link to position in previous scope this scope 58/// began in. 59/// 60/// The process of creating local scopes is as follows: 61/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 62/// - Before processing statements in scope (e.g. CompoundStmt) create 63/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 64/// and set CFGBuilder::ScopePos to the end of new scope, 65/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 66/// at this VarDecl, 67/// - For every normal (without jump) end of scope add to CFGBlock destructors 68/// for objects in the current scope, 69/// - For every jump add to CFGBlock destructors for objects 70/// between CFGBuilder::ScopePos and local scope position saved for jump 71/// target. Thanks to C++ restrictions on goto jumps we can be sure that 72/// jump target position will be on the path to root from CFGBuilder::ScopePos 73/// (adding any variable that doesn't need constructor to be called to 74/// LocalScope can break this assumption), 75/// 76class LocalScope { 77public: 78 typedef llvm::SmallVector<VarDecl*, 4> AutomaticVarsTy; 79 80 /// const_iterator - Iterates local scope backwards and jumps to previous 81 /// scope on reaching the beginning of currently iterated scope. 82 class const_iterator { 83 const LocalScope* Scope; 84 85 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 86 /// Invalid iterator (with null Scope) has VarIter equal to 0. 87 unsigned VarIter; 88 89 public: 90 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 91 /// Incrementing invalid iterator is allowed and will result in invalid 92 /// iterator. 93 const_iterator() 94 : Scope(NULL), VarIter(0) {} 95 96 /// Create valid iterator. In case when S.Prev is an invalid iterator and 97 /// I is equal to 0, this will create invalid iterator. 98 const_iterator(const LocalScope& S, unsigned I) 99 : Scope(&S), VarIter(I) { 100 // Iterator to "end" of scope is not allowed. Handle it by going up 101 // in scopes tree possibly up to invalid iterator in the root. 102 if (VarIter == 0 && Scope) 103 *this = Scope->Prev; 104 } 105 106 VarDecl* const* operator->() const { 107 assert (Scope && "Dereferencing invalid iterator is not allowed"); 108 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 109 return &Scope->Vars[VarIter - 1]; 110 } 111 VarDecl* operator*() const { 112 return *this->operator->(); 113 } 114 115 const_iterator& operator++() { 116 if (!Scope) 117 return *this; 118 119 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 120 --VarIter; 121 if (VarIter == 0) 122 *this = Scope->Prev; 123 return *this; 124 } 125 const_iterator operator++(int) { 126 const_iterator P = *this; 127 ++*this; 128 return P; 129 } 130 131 bool operator==(const const_iterator& rhs) const { 132 return Scope == rhs.Scope && VarIter == rhs.VarIter; 133 } 134 bool operator!=(const const_iterator& rhs) const { 135 return !(*this == rhs); 136 } 137 138 operator bool() const { 139 return *this != const_iterator(); 140 } 141 142 int distance(const_iterator L); 143 }; 144 145 friend class const_iterator; 146 147private: 148 /// Automatic variables in order of declaration. 149 AutomaticVarsTy Vars; 150 /// Iterator to variable in previous scope that was declared just before 151 /// begin of this scope. 152 const_iterator Prev; 153 154public: 155 /// Constructs empty scope linked to previous scope in specified place. 156 LocalScope(const_iterator P) 157 : Vars() 158 , Prev(P) {} 159 160 /// Begin of scope in direction of CFG building (backwards). 161 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 162 163 void addVar(VarDecl* VD) { 164 Vars.push_back(VD); 165 } 166}; 167 168/// distance - Calculates distance from this to L. L must be reachable from this 169/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 170/// number of scopes between this and L. 171int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 172 int D = 0; 173 const_iterator F = *this; 174 while (F.Scope != L.Scope) { 175 assert (F != const_iterator() 176 && "L iterator is not reachable from F iterator."); 177 D += F.VarIter; 178 F = F.Scope->Prev; 179 } 180 D += F.VarIter - L.VarIter; 181 return D; 182} 183 184/// BlockScopePosPair - Structure for specifying position in CFG during its 185/// build process. It consists of CFGBlock that specifies position in CFG graph 186/// and LocalScope::const_iterator that specifies position in LocalScope graph. 187struct BlockScopePosPair { 188 BlockScopePosPair() {} 189 BlockScopePosPair(CFGBlock* B, LocalScope::const_iterator S) 190 : Block(B), ScopePos(S) {} 191 192 CFGBlock* Block; 193 LocalScope::const_iterator ScopePos; 194}; 195 196/// CFGBuilder - This class implements CFG construction from an AST. 197/// The builder is stateful: an instance of the builder should be used to only 198/// construct a single CFG. 199/// 200/// Example usage: 201/// 202/// CFGBuilder builder; 203/// CFG* cfg = builder.BuildAST(stmt1); 204/// 205/// CFG construction is done via a recursive walk of an AST. We actually parse 206/// the AST in reverse order so that the successor of a basic block is 207/// constructed prior to its predecessor. This allows us to nicely capture 208/// implicit fall-throughs without extra basic blocks. 209/// 210class CFGBuilder { 211 typedef BlockScopePosPair JumpTarget; 212 typedef BlockScopePosPair JumpSource; 213 214 ASTContext *Context; 215 llvm::OwningPtr<CFG> cfg; 216 217 CFGBlock* Block; 218 CFGBlock* Succ; 219 JumpTarget ContinueJumpTarget; 220 JumpTarget BreakJumpTarget; 221 CFGBlock* SwitchTerminatedBlock; 222 CFGBlock* DefaultCaseBlock; 223 CFGBlock* TryTerminatedBlock; 224 225 // Current position in local scope. 226 LocalScope::const_iterator ScopePos; 227 228 // LabelMap records the mapping from Label expressions to their jump targets. 229 typedef llvm::DenseMap<LabelStmt*, JumpTarget> LabelMapTy; 230 LabelMapTy LabelMap; 231 232 // A list of blocks that end with a "goto" that must be backpatched to their 233 // resolved targets upon completion of CFG construction. 234 typedef std::vector<JumpSource> BackpatchBlocksTy; 235 BackpatchBlocksTy BackpatchBlocks; 236 237 // A list of labels whose address has been taken (for indirect gotos). 238 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 239 LabelSetTy AddressTakenLabels; 240 241 bool badCFG; 242 CFG::BuildOptions BuildOpts; 243 244public: 245 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 246 Block(NULL), Succ(NULL), 247 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 248 TryTerminatedBlock(NULL), badCFG(false) {} 249 250 // buildCFG - Used by external clients to construct the CFG. 251 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 252 CFG::BuildOptions BO); 253 254private: 255 // Visitors to walk an AST and construct the CFG. 256 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 257 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 258 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 259 CFGBlock *VisitBreakStmt(BreakStmt *B); 260 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 261 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 262 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 263 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 264 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 265 CFGBlock *VisitCaseStmt(CaseStmt *C); 266 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 267 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 268 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 269 CFGBlock *VisitContinueStmt(ContinueStmt *C); 270 CFGBlock *VisitDeclStmt(DeclStmt *DS); 271 CFGBlock *VisitDeclSubExpr(Decl* D); 272 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 273 CFGBlock *VisitDoStmt(DoStmt *D); 274 CFGBlock *VisitForStmt(ForStmt *F); 275 CFGBlock *VisitGotoStmt(GotoStmt* G); 276 CFGBlock *VisitIfStmt(IfStmt *I); 277 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 278 CFGBlock *VisitLabelStmt(LabelStmt *L); 279 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 280 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 281 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 282 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 283 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 284 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 285 CFGBlock *VisitReturnStmt(ReturnStmt* R); 286 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 287 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 288 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 289 CFGBlock *VisitWhileStmt(WhileStmt *W); 290 291 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 292 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 293 CFGBlock *VisitChildren(Stmt* S); 294 295 // NYS == Not Yet Supported 296 CFGBlock* NYS() { 297 badCFG = true; 298 return Block; 299 } 300 301 void autoCreateBlock() { if (!Block) Block = createBlock(); } 302 CFGBlock *createBlock(bool add_successor = true); 303 304 CFGBlock *addStmt(Stmt *S) { 305 return Visit(S, AddStmtChoice::AlwaysAdd); 306 } 307 CFGBlock *addAutomaticObjDtors(LocalScope::const_iterator B, 308 LocalScope::const_iterator E, Stmt* S); 309 310 // Local scopes creation. 311 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 312 313 LocalScope* addLocalScopeForStmt(Stmt* S, LocalScope* Scope = NULL); 314 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 315 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 316 317 void addLocalScopeAndDtors(Stmt* S); 318 319 // Interface to CFGBlock - adding CFGElements. 320 void AppendStmt(CFGBlock *B, Stmt *S, 321 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 322 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 323 } 324 325 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 326 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 327 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 328 LocalScope::const_iterator E, Stmt* S); 329 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 330 LocalScope::const_iterator B, LocalScope::const_iterator E); 331 332 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 333 B->addSuccessor(S, cfg->getBumpVectorContext()); 334 } 335 336 /// TryResult - a class representing a variant over the values 337 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 338 /// and is used by the CFGBuilder to decide if a branch condition 339 /// can be decided up front during CFG construction. 340 class TryResult { 341 int X; 342 public: 343 TryResult(bool b) : X(b ? 1 : 0) {} 344 TryResult() : X(-1) {} 345 346 bool isTrue() const { return X == 1; } 347 bool isFalse() const { return X == 0; } 348 bool isKnown() const { return X >= 0; } 349 void negate() { 350 assert(isKnown()); 351 X ^= 0x1; 352 } 353 }; 354 355 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 356 /// if we can evaluate to a known value, otherwise return -1. 357 TryResult TryEvaluateBool(Expr *S) { 358 if (!BuildOpts.PruneTriviallyFalseEdges) 359 return TryResult(); 360 361 Expr::EvalResult Result; 362 if (!S->isTypeDependent() && !S->isValueDependent() && 363 S->Evaluate(Result, *Context) && Result.Val.isInt()) 364 return Result.Val.getInt().getBoolValue(); 365 366 return TryResult(); 367 } 368}; 369 370// FIXME: Add support for dependent-sized array types in C++? 371// Does it even make sense to build a CFG for an uninstantiated template? 372static VariableArrayType* FindVA(Type* t) { 373 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 374 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 375 if (vat->getSizeExpr()) 376 return vat; 377 378 t = vt->getElementType().getTypePtr(); 379 } 380 381 return 0; 382} 383 384/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 385/// arbitrary statement. Examples include a single expression or a function 386/// body (compound statement). The ownership of the returned CFG is 387/// transferred to the caller. If CFG construction fails, this method returns 388/// NULL. 389CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 390 CFG::BuildOptions BO) { 391 392 Context = C; 393 assert(cfg.get()); 394 if (!Statement) 395 return NULL; 396 397 BuildOpts = BO; 398 if (!C->getLangOptions().CPlusPlus) 399 BuildOpts.AddImplicitDtors = false; 400 401 // Create an empty block that will serve as the exit block for the CFG. Since 402 // this is the first block added to the CFG, it will be implicitly registered 403 // as the exit block. 404 Succ = createBlock(); 405 assert(Succ == &cfg->getExit()); 406 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 407 408 // Visit the statements and create the CFG. 409 CFGBlock *B = addStmt(Statement); 410 411 if (badCFG) 412 return NULL; 413 414 if (B) 415 Succ = B; 416 417 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 418 // FIXME: Add code for base initializers and member initializers. 419 (void)CD; 420 } 421 422 // Backpatch the gotos whose label -> block mappings we didn't know when we 423 // encountered them. 424 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 425 E = BackpatchBlocks.end(); I != E; ++I ) { 426 427 CFGBlock* B = I->Block; 428 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 429 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 430 431 // If there is no target for the goto, then we are looking at an 432 // incomplete AST. Handle this by not registering a successor. 433 if (LI == LabelMap.end()) continue; 434 435 JumpTarget JT = LI->second; 436 prependAutomaticObjDtorsWithTerminator(B, I->ScopePos, JT.ScopePos); 437 AddSuccessor(B, JT.Block); 438 } 439 440 // Add successors to the Indirect Goto Dispatch block (if we have one). 441 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 442 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 443 E = AddressTakenLabels.end(); I != E; ++I ) { 444 445 // Lookup the target block. 446 LabelMapTy::iterator LI = LabelMap.find(*I); 447 448 // If there is no target block that contains label, then we are looking 449 // at an incomplete AST. Handle this by not registering a successor. 450 if (LI == LabelMap.end()) continue; 451 452 AddSuccessor(B, LI->second.Block); 453 } 454 455 // Create an empty entry block that has no predecessors. 456 cfg->setEntry(createBlock()); 457 458 return cfg.take(); 459} 460 461/// createBlock - Used to lazily create blocks that are connected 462/// to the current (global) succcessor. 463CFGBlock* CFGBuilder::createBlock(bool add_successor) { 464 CFGBlock* B = cfg->createBlock(); 465 if (add_successor && Succ) 466 AddSuccessor(B, Succ); 467 return B; 468} 469 470/// addAutomaticObjDtors - Add to current block automatic objects destructors 471/// for objects in range of local scope positions. Use S as trigger statement 472/// for destructors. 473CFGBlock* CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 474 LocalScope::const_iterator E, Stmt* S) { 475 if (!BuildOpts.AddImplicitDtors) 476 return Block; 477 if (B == E) 478 return Block; 479 480 autoCreateBlock(); 481 appendAutomaticObjDtors(Block, B, E, S); 482 return Block; 483} 484 485/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 486/// way return valid LocalScope object. 487LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 488 if (!Scope) { 489 Scope = cfg->getAllocator().Allocate<LocalScope>(); 490 new (Scope) LocalScope(ScopePos); 491 } 492 return Scope; 493} 494 495/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 496/// that should create implicit scope (e.g. if/else substatements). Will reuse 497/// Scope if not NULL. 498LocalScope* CFGBuilder::addLocalScopeForStmt(Stmt* S, LocalScope* Scope) { 499 if (!BuildOpts.AddImplicitDtors) 500 return Scope; 501 502 // For compound statement we will be creating explicit scope. 503 if (CompoundStmt* CS = dyn_cast<CompoundStmt>(S)) { 504 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 505 ; BI != BE; ++BI) { 506 Stmt* SI = *BI; 507 if (LabelStmt* LS = dyn_cast<LabelStmt>(SI)) 508 SI = LS->getSubStmt(); 509 if (DeclStmt* DS = dyn_cast<DeclStmt>(SI)) 510 Scope = addLocalScopeForDeclStmt(DS, Scope); 511 } 512 return Scope; 513 } 514 515 // For any other statement scope will be implicit and as such will be 516 // interesting only for DeclStmt. 517 if (LabelStmt* LS = dyn_cast<LabelStmt>(S)) 518 S = LS->getSubStmt(); 519 if (DeclStmt* DS = dyn_cast<DeclStmt>(S)) 520 Scope = addLocalScopeForDeclStmt(DS, Scope); 521 return Scope; 522} 523 524/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 525/// reuse Scope if not NULL. 526LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 527 LocalScope* Scope) { 528 if (!BuildOpts.AddImplicitDtors) 529 return Scope; 530 531 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 532 ; DI != DE; ++DI) { 533 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 534 Scope = addLocalScopeForVarDecl(VD, Scope); 535 } 536 return Scope; 537} 538 539/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 540/// create add scope for automatic objects and temporary objects bound to 541/// const reference. Will reuse Scope if not NULL. 542LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 543 LocalScope* Scope) { 544 if (!BuildOpts.AddImplicitDtors) 545 return Scope; 546 547 // Check if variable is local. 548 switch (VD->getStorageClass()) { 549 case SC_None: 550 case SC_Auto: 551 case SC_Register: 552 break; 553 default: return Scope; 554 } 555 556 // Check for const references bound to temporary. Set type to pointee. 557 QualType QT = VD->getType(); 558 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 559 QT = RT->getPointeeType(); 560 if (!QT.isConstQualified()) 561 return Scope; 562 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 563 return Scope; 564 } 565 566 // Check if type is a C++ class with non-trivial destructor. 567 if (const RecordType* RT = QT.getTypePtr()->getAs<RecordType>()) 568 if (const CXXRecordDecl* CD = dyn_cast<CXXRecordDecl>(RT->getDecl())) 569 if (CD->hasTrivialDestructor()) 570 return Scope; 571 572 // Add the variable to scope 573 Scope = createOrReuseLocalScope(Scope); 574 Scope->addVar(VD); 575 ScopePos = Scope->begin(); 576 return Scope; 577} 578 579/// addLocalScopeAndDtors - For given statement add local scope for it and 580/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 581void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 582 if (!BuildOpts.AddImplicitDtors) 583 return; 584 585 LocalScope::const_iterator scopeBeginPos = ScopePos; 586 addLocalScopeForStmt(S, NULL); 587 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 588} 589 590/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 591/// automatic storage duration to CFGBlock's elements vector. Insertion will be 592/// performed in place specified with iterator. 593void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 594 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 595 BumpVectorContext& C = cfg->getBumpVectorContext(); 596 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 597 while (B != E) 598 I = Blk->insertAutomaticObjDtor(I, *B++, S); 599} 600 601/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 602/// automatic storage duration to CFGBlock's elements vector. Elements will be 603/// appended to physical end of the vector which happens to be logical 604/// beginning. 605void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 606 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 607 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 608} 609 610/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 611/// variables with automatic storage duration to CFGBlock's elements vector. 612/// Elements will be prepended to physical beginning of the vector which 613/// happens to be logical end. Use blocks terminator as statement that specifies 614/// destructors call site. 615void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 616 LocalScope::const_iterator B, LocalScope::const_iterator E) { 617 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 618} 619 620/// Visit - Walk the subtree of a statement and add extra 621/// blocks for ternary operators, &&, and ||. We also process "," and 622/// DeclStmts (which may contain nested control-flow). 623CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 624tryAgain: 625 if (!S) { 626 badCFG = true; 627 return 0; 628 } 629 switch (S->getStmtClass()) { 630 default: 631 return VisitStmt(S, asc); 632 633 case Stmt::AddrLabelExprClass: 634 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 635 636 case Stmt::BinaryOperatorClass: 637 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 638 639 case Stmt::BlockExprClass: 640 return VisitBlockExpr(cast<BlockExpr>(S), asc); 641 642 case Stmt::BreakStmtClass: 643 return VisitBreakStmt(cast<BreakStmt>(S)); 644 645 case Stmt::CallExprClass: 646 case Stmt::CXXOperatorCallExprClass: 647 return VisitCallExpr(cast<CallExpr>(S), asc); 648 649 case Stmt::CaseStmtClass: 650 return VisitCaseStmt(cast<CaseStmt>(S)); 651 652 case Stmt::ChooseExprClass: 653 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 654 655 case Stmt::CompoundStmtClass: 656 return VisitCompoundStmt(cast<CompoundStmt>(S)); 657 658 case Stmt::ConditionalOperatorClass: 659 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 660 661 case Stmt::ContinueStmtClass: 662 return VisitContinueStmt(cast<ContinueStmt>(S)); 663 664 case Stmt::CXXCatchStmtClass: 665 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 666 667 case Stmt::CXXExprWithTemporariesClass: { 668 // FIXME: Handle temporaries. For now, just visit the subexpression 669 // so we don't artificially create extra blocks. 670 return Visit(cast<CXXExprWithTemporaries>(S)->getSubExpr(), asc); 671 } 672 673 case Stmt::CXXMemberCallExprClass: 674 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 675 676 case Stmt::CXXThrowExprClass: 677 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 678 679 case Stmt::CXXTryStmtClass: 680 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 681 682 case Stmt::DeclStmtClass: 683 return VisitDeclStmt(cast<DeclStmt>(S)); 684 685 case Stmt::DefaultStmtClass: 686 return VisitDefaultStmt(cast<DefaultStmt>(S)); 687 688 case Stmt::DoStmtClass: 689 return VisitDoStmt(cast<DoStmt>(S)); 690 691 case Stmt::ForStmtClass: 692 return VisitForStmt(cast<ForStmt>(S)); 693 694 case Stmt::GotoStmtClass: 695 return VisitGotoStmt(cast<GotoStmt>(S)); 696 697 case Stmt::IfStmtClass: 698 return VisitIfStmt(cast<IfStmt>(S)); 699 700 case Stmt::IndirectGotoStmtClass: 701 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 702 703 case Stmt::LabelStmtClass: 704 return VisitLabelStmt(cast<LabelStmt>(S)); 705 706 case Stmt::MemberExprClass: 707 return VisitMemberExpr(cast<MemberExpr>(S), asc); 708 709 case Stmt::ObjCAtCatchStmtClass: 710 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 711 712 case Stmt::ObjCAtSynchronizedStmtClass: 713 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 714 715 case Stmt::ObjCAtThrowStmtClass: 716 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 717 718 case Stmt::ObjCAtTryStmtClass: 719 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 720 721 case Stmt::ObjCForCollectionStmtClass: 722 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 723 724 case Stmt::ParenExprClass: 725 S = cast<ParenExpr>(S)->getSubExpr(); 726 goto tryAgain; 727 728 case Stmt::NullStmtClass: 729 return Block; 730 731 case Stmt::ReturnStmtClass: 732 return VisitReturnStmt(cast<ReturnStmt>(S)); 733 734 case Stmt::SizeOfAlignOfExprClass: 735 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 736 737 case Stmt::StmtExprClass: 738 return VisitStmtExpr(cast<StmtExpr>(S), asc); 739 740 case Stmt::SwitchStmtClass: 741 return VisitSwitchStmt(cast<SwitchStmt>(S)); 742 743 case Stmt::WhileStmtClass: 744 return VisitWhileStmt(cast<WhileStmt>(S)); 745 } 746} 747 748CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 749 if (asc.alwaysAdd()) { 750 autoCreateBlock(); 751 AppendStmt(Block, S, asc); 752 } 753 754 return VisitChildren(S); 755} 756 757/// VisitChildren - Visit the children of a Stmt. 758CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 759 CFGBlock *B = Block; 760 for (Stmt::child_iterator I = Terminator->child_begin(), 761 E = Terminator->child_end(); I != E; ++I) { 762 if (*I) B = Visit(*I); 763 } 764 return B; 765} 766 767CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 768 AddStmtChoice asc) { 769 AddressTakenLabels.insert(A->getLabel()); 770 771 if (asc.alwaysAdd()) { 772 autoCreateBlock(); 773 AppendStmt(Block, A, asc); 774 } 775 776 return Block; 777} 778 779CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 780 AddStmtChoice asc) { 781 if (B->isLogicalOp()) { // && or || 782 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 783 AppendStmt(ConfluenceBlock, B, asc); 784 785 if (badCFG) 786 return 0; 787 788 // create the block evaluating the LHS 789 CFGBlock* LHSBlock = createBlock(false); 790 LHSBlock->setTerminator(B); 791 792 // create the block evaluating the RHS 793 Succ = ConfluenceBlock; 794 Block = NULL; 795 CFGBlock* RHSBlock = addStmt(B->getRHS()); 796 797 if (RHSBlock) { 798 if (badCFG) 799 return 0; 800 } 801 else { 802 // Create an empty block for cases where the RHS doesn't require 803 // any explicit statements in the CFG. 804 RHSBlock = createBlock(); 805 } 806 807 // See if this is a known constant. 808 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 809 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 810 KnownVal.negate(); 811 812 // Now link the LHSBlock with RHSBlock. 813 if (B->getOpcode() == BO_LOr) { 814 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 815 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 816 } else { 817 assert(B->getOpcode() == BO_LAnd); 818 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 819 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 820 } 821 822 // Generate the blocks for evaluating the LHS. 823 Block = LHSBlock; 824 return addStmt(B->getLHS()); 825 } 826 else if (B->getOpcode() == BO_Comma) { // , 827 autoCreateBlock(); 828 AppendStmt(Block, B, asc); 829 addStmt(B->getRHS()); 830 return addStmt(B->getLHS()); 831 } 832 else if (B->isAssignmentOp()) { 833 if (asc.alwaysAdd()) { 834 autoCreateBlock(); 835 AppendStmt(Block, B, asc); 836 } 837 838 // If visiting RHS causes us to finish 'Block' and the LHS doesn't 839 // create a new block, then we should return RBlock. Otherwise 840 // we'll incorrectly return NULL. 841 CFGBlock *RBlock = Visit(B->getRHS()); 842 CFGBlock *LBlock = Visit(B->getLHS(), AddStmtChoice::AsLValueNotAlwaysAdd); 843 return LBlock ? LBlock : RBlock; 844 } 845 846 return VisitStmt(B, asc); 847} 848 849CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 850 if (asc.alwaysAdd()) { 851 autoCreateBlock(); 852 AppendStmt(Block, E, asc); 853 } 854 return Block; 855} 856 857CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 858 // "break" is a control-flow statement. Thus we stop processing the current 859 // block. 860 if (badCFG) 861 return 0; 862 863 // Now create a new block that ends with the break statement. 864 Block = createBlock(false); 865 Block->setTerminator(B); 866 867 // If there is no target for the break, then we are looking at an incomplete 868 // AST. This means that the CFG cannot be constructed. 869 if (BreakJumpTarget.Block) { 870 addAutomaticObjDtors(ScopePos, BreakJumpTarget.ScopePos, B); 871 AddSuccessor(Block, BreakJumpTarget.Block); 872 } else 873 badCFG = true; 874 875 876 return Block; 877} 878 879static bool CanThrow(Expr *E) { 880 QualType Ty = E->getType(); 881 if (Ty->isFunctionPointerType()) 882 Ty = Ty->getAs<PointerType>()->getPointeeType(); 883 else if (Ty->isBlockPointerType()) 884 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 885 886 const FunctionType *FT = Ty->getAs<FunctionType>(); 887 if (FT) { 888 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 889 if (Proto->hasEmptyExceptionSpec()) 890 return false; 891 } 892 return true; 893} 894 895CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 896 // If this is a call to a no-return function, this stops the block here. 897 bool NoReturn = false; 898 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 899 NoReturn = true; 900 } 901 902 bool AddEHEdge = false; 903 904 // Languages without exceptions are assumed to not throw. 905 if (Context->getLangOptions().Exceptions) { 906 if (BuildOpts.AddEHEdges) 907 AddEHEdge = true; 908 } 909 910 if (FunctionDecl *FD = C->getDirectCallee()) { 911 if (FD->hasAttr<NoReturnAttr>()) 912 NoReturn = true; 913 if (FD->hasAttr<NoThrowAttr>()) 914 AddEHEdge = false; 915 } 916 917 if (!CanThrow(C->getCallee())) 918 AddEHEdge = false; 919 920 if (!NoReturn && !AddEHEdge) { 921 if (asc.asLValue()) 922 return VisitStmt(C, AddStmtChoice::AlwaysAddAsLValue); 923 else 924 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 925 } 926 927 if (Block) { 928 Succ = Block; 929 if (badCFG) 930 return 0; 931 } 932 933 Block = createBlock(!NoReturn); 934 AppendStmt(Block, C, asc); 935 936 if (NoReturn) { 937 // Wire this to the exit block directly. 938 AddSuccessor(Block, &cfg->getExit()); 939 } 940 if (AddEHEdge) { 941 // Add exceptional edges. 942 if (TryTerminatedBlock) 943 AddSuccessor(Block, TryTerminatedBlock); 944 else 945 AddSuccessor(Block, &cfg->getExit()); 946 } 947 948 return VisitChildren(C); 949} 950 951CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 952 AddStmtChoice asc) { 953 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 954 AppendStmt(ConfluenceBlock, C, asc); 955 if (badCFG) 956 return 0; 957 958 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 959 : AddStmtChoice::AlwaysAdd; 960 961 Succ = ConfluenceBlock; 962 Block = NULL; 963 CFGBlock* LHSBlock = Visit(C->getLHS(), asc); 964 if (badCFG) 965 return 0; 966 967 Succ = ConfluenceBlock; 968 Block = NULL; 969 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 970 if (badCFG) 971 return 0; 972 973 Block = createBlock(false); 974 // See if this is a known constant. 975 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 976 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 977 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 978 Block->setTerminator(C); 979 return addStmt(C->getCond()); 980} 981 982 983CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 984 addLocalScopeAndDtors(C); 985 CFGBlock* LastBlock = Block; 986 987 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 988 I != E; ++I ) { 989 // If we hit a segment of code just containing ';' (NullStmts), we can 990 // get a null block back. In such cases, just use the LastBlock 991 if (CFGBlock *newBlock = addStmt(*I)) 992 LastBlock = newBlock; 993 994 if (badCFG) 995 return NULL; 996 } 997 998 return LastBlock; 999} 1000 1001CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 1002 AddStmtChoice asc) { 1003 // Create the confluence block that will "merge" the results of the ternary 1004 // expression. 1005 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1006 AppendStmt(ConfluenceBlock, C, asc); 1007 if (badCFG) 1008 return 0; 1009 1010 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1011 : AddStmtChoice::AlwaysAdd; 1012 1013 // Create a block for the LHS expression if there is an LHS expression. A 1014 // GCC extension allows LHS to be NULL, causing the condition to be the 1015 // value that is returned instead. 1016 // e.g: x ?: y is shorthand for: x ? x : y; 1017 Succ = ConfluenceBlock; 1018 Block = NULL; 1019 CFGBlock* LHSBlock = NULL; 1020 if (C->getLHS()) { 1021 LHSBlock = Visit(C->getLHS(), asc); 1022 if (badCFG) 1023 return 0; 1024 Block = NULL; 1025 } 1026 1027 // Create the block for the RHS expression. 1028 Succ = ConfluenceBlock; 1029 CFGBlock* RHSBlock = Visit(C->getRHS(), asc); 1030 if (badCFG) 1031 return 0; 1032 1033 // Create the block that will contain the condition. 1034 Block = createBlock(false); 1035 1036 // See if this is a known constant. 1037 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 1038 if (LHSBlock) { 1039 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1040 } else { 1041 if (KnownVal.isFalse()) { 1042 // If we know the condition is false, add NULL as the successor for 1043 // the block containing the condition. In this case, the confluence 1044 // block will have just one predecessor. 1045 AddSuccessor(Block, 0); 1046 assert(ConfluenceBlock->pred_size() == 1); 1047 } else { 1048 // If we have no LHS expression, add the ConfluenceBlock as a direct 1049 // successor for the block containing the condition. Moreover, we need to 1050 // reverse the order of the predecessors in the ConfluenceBlock because 1051 // the RHSBlock will have been added to the succcessors already, and we 1052 // want the first predecessor to the the block containing the expression 1053 // for the case when the ternary expression evaluates to true. 1054 AddSuccessor(Block, ConfluenceBlock); 1055 assert(ConfluenceBlock->pred_size() == 2); 1056 std::reverse(ConfluenceBlock->pred_begin(), 1057 ConfluenceBlock->pred_end()); 1058 } 1059 } 1060 1061 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1062 Block->setTerminator(C); 1063 return addStmt(C->getCond()); 1064} 1065 1066CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1067 autoCreateBlock(); 1068 1069 if (DS->isSingleDecl()) { 1070 AppendStmt(Block, DS); 1071 return VisitDeclSubExpr(DS->getSingleDecl()); 1072 } 1073 1074 CFGBlock *B = 0; 1075 1076 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1077 typedef llvm::SmallVector<Decl*,10> BufTy; 1078 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1079 1080 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1081 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1082 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1083 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1084 1085 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1086 // automatically freed with the CFG. 1087 DeclGroupRef DG(*I); 1088 Decl *D = *I; 1089 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1090 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1091 1092 // Append the fake DeclStmt to block. 1093 AppendStmt(Block, DSNew); 1094 B = VisitDeclSubExpr(D); 1095 } 1096 1097 return B; 1098} 1099 1100/// VisitDeclSubExpr - Utility method to add block-level expressions for 1101/// initializers in Decls. 1102CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 1103 assert(Block); 1104 1105 VarDecl *VD = dyn_cast<VarDecl>(D); 1106 1107 if (!VD) 1108 return Block; 1109 1110 Expr *Init = VD->getInit(); 1111 1112 if (Init) { 1113 AddStmtChoice::Kind k = 1114 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 1115 : AddStmtChoice::NotAlwaysAdd; 1116 Visit(Init, AddStmtChoice(k)); 1117 } 1118 1119 // If the type of VD is a VLA, then we must process its size expressions. 1120 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 1121 VA = FindVA(VA->getElementType().getTypePtr())) 1122 Block = addStmt(VA->getSizeExpr()); 1123 1124 // Remove variable from local scope. 1125 if (ScopePos && VD == *ScopePos) 1126 ++ScopePos; 1127 1128 return Block; 1129} 1130 1131CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1132 // We may see an if statement in the middle of a basic block, or it may be the 1133 // first statement we are processing. In either case, we create a new basic 1134 // block. First, we create the blocks for the then...else statements, and 1135 // then we create the block containing the if statement. If we were in the 1136 // middle of a block, we stop processing that block. That block is then the 1137 // implicit successor for the "then" and "else" clauses. 1138 1139 // Save local scope position because in case of condition variable ScopePos 1140 // won't be restored when traversing AST. 1141 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1142 1143 // Create local scope for possible condition variable. 1144 // Store scope position. Add implicit destructor. 1145 if (VarDecl* VD = I->getConditionVariable()) { 1146 LocalScope::const_iterator BeginScopePos = ScopePos; 1147 addLocalScopeForVarDecl(VD); 1148 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1149 } 1150 1151 // The block we were proccessing is now finished. Make it the successor 1152 // block. 1153 if (Block) { 1154 Succ = Block; 1155 if (badCFG) 1156 return 0; 1157 } 1158 1159 // Process the false branch. 1160 CFGBlock* ElseBlock = Succ; 1161 1162 if (Stmt* Else = I->getElse()) { 1163 SaveAndRestore<CFGBlock*> sv(Succ); 1164 1165 // NULL out Block so that the recursive call to Visit will 1166 // create a new basic block. 1167 Block = NULL; 1168 1169 // If branch is not a compound statement create implicit scope 1170 // and add destructors. 1171 if (!isa<CompoundStmt>(Else)) 1172 addLocalScopeAndDtors(Else); 1173 1174 ElseBlock = addStmt(Else); 1175 1176 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1177 ElseBlock = sv.get(); 1178 else if (Block) { 1179 if (badCFG) 1180 return 0; 1181 } 1182 } 1183 1184 // Process the true branch. 1185 CFGBlock* ThenBlock; 1186 { 1187 Stmt* Then = I->getThen(); 1188 assert(Then); 1189 SaveAndRestore<CFGBlock*> sv(Succ); 1190 Block = NULL; 1191 1192 // If branch is not a compound statement create implicit scope 1193 // and add destructors. 1194 if (!isa<CompoundStmt>(Then)) 1195 addLocalScopeAndDtors(Then); 1196 1197 ThenBlock = addStmt(Then); 1198 1199 if (!ThenBlock) { 1200 // We can reach here if the "then" body has all NullStmts. 1201 // Create an empty block so we can distinguish between true and false 1202 // branches in path-sensitive analyses. 1203 ThenBlock = createBlock(false); 1204 AddSuccessor(ThenBlock, sv.get()); 1205 } else if (Block) { 1206 if (badCFG) 1207 return 0; 1208 } 1209 } 1210 1211 // Now create a new block containing the if statement. 1212 Block = createBlock(false); 1213 1214 // Set the terminator of the new block to the If statement. 1215 Block->setTerminator(I); 1216 1217 // See if this is a known constant. 1218 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 1219 1220 // Now add the successors. 1221 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1222 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1223 1224 // Add the condition as the last statement in the new block. This may create 1225 // new blocks as the condition may contain control-flow. Any newly created 1226 // blocks will be pointed to be "Block". 1227 Block = addStmt(I->getCond()); 1228 1229 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1230 // and the condition variable initialization to the CFG. 1231 if (VarDecl *VD = I->getConditionVariable()) { 1232 if (Expr *Init = VD->getInit()) { 1233 autoCreateBlock(); 1234 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 1235 addStmt(Init); 1236 } 1237 } 1238 1239 return Block; 1240} 1241 1242 1243CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1244 // If we were in the middle of a block we stop processing that block. 1245 // 1246 // NOTE: If a "return" appears in the middle of a block, this means that the 1247 // code afterwards is DEAD (unreachable). We still keep a basic block 1248 // for that code; a simple "mark-and-sweep" from the entry block will be 1249 // able to report such dead blocks. 1250 1251 // Create the new block. 1252 Block = createBlock(false); 1253 1254 // The Exit block is the only successor. 1255 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1256 AddSuccessor(Block, &cfg->getExit()); 1257 1258 // Add the return statement to the block. This may create new blocks if R 1259 // contains control-flow (short-circuit operations). 1260 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1261} 1262 1263CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 1264 // Get the block of the labeled statement. Add it to our map. 1265 addStmt(L->getSubStmt()); 1266 CFGBlock* LabelBlock = Block; 1267 1268 if (!LabelBlock) // This can happen when the body is empty, i.e. 1269 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1270 1271 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 1272 LabelMap[ L ] = JumpTarget(LabelBlock, ScopePos); 1273 1274 // Labels partition blocks, so this is the end of the basic block we were 1275 // processing (L is the block's label). Because this is label (and we have 1276 // already processed the substatement) there is no extra control-flow to worry 1277 // about. 1278 LabelBlock->setLabel(L); 1279 if (badCFG) 1280 return 0; 1281 1282 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1283 Block = NULL; 1284 1285 // This block is now the implicit successor of other blocks. 1286 Succ = LabelBlock; 1287 1288 return LabelBlock; 1289} 1290 1291CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1292 // Goto is a control-flow statement. Thus we stop processing the current 1293 // block and create a new one. 1294 1295 Block = createBlock(false); 1296 Block->setTerminator(G); 1297 1298 // If we already know the mapping to the label block add the successor now. 1299 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1300 1301 if (I == LabelMap.end()) 1302 // We will need to backpatch this block later. 1303 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1304 else { 1305 JumpTarget JT = I->second; 1306 addAutomaticObjDtors(ScopePos, JT.ScopePos, G); 1307 AddSuccessor(Block, JT.Block); 1308 } 1309 1310 return Block; 1311} 1312 1313CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1314 CFGBlock* LoopSuccessor = NULL; 1315 1316 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1317 1318 // "for" is a control-flow statement. Thus we stop processing the current 1319 // block. 1320 if (Block) { 1321 if (badCFG) 1322 return 0; 1323 LoopSuccessor = Block; 1324 } else 1325 LoopSuccessor = Succ; 1326 1327 // Save the current value for the break targets. 1328 // All breaks should go to the code following the loop. 1329 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1330 BreakJumpTarget = JumpTarget(LoopSuccessor, LoopBeginScopePos); 1331 1332 // Because of short-circuit evaluation, the condition of the loop can span 1333 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1334 // evaluate the condition. 1335 CFGBlock* ExitConditionBlock = createBlock(false); 1336 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1337 1338 // Set the terminator for the "exit" condition block. 1339 ExitConditionBlock->setTerminator(F); 1340 1341 // Now add the actual condition to the condition block. Because the condition 1342 // itself may contain control-flow, new blocks may be created. 1343 if (Stmt* C = F->getCond()) { 1344 Block = ExitConditionBlock; 1345 EntryConditionBlock = addStmt(C); 1346 assert(Block == EntryConditionBlock || 1347 (Block == 0 && EntryConditionBlock == Succ)); 1348 1349 // If this block contains a condition variable, add both the condition 1350 // variable and initializer to the CFG. 1351 if (VarDecl *VD = F->getConditionVariable()) { 1352 if (Expr *Init = VD->getInit()) { 1353 autoCreateBlock(); 1354 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1355 EntryConditionBlock = addStmt(Init); 1356 assert(Block == EntryConditionBlock); 1357 } 1358 } 1359 1360 if (Block) { 1361 if (badCFG) 1362 return 0; 1363 } 1364 } 1365 1366 // The condition block is the implicit successor for the loop body as well as 1367 // any code above the loop. 1368 Succ = EntryConditionBlock; 1369 1370 // See if this is a known constant. 1371 TryResult KnownVal(true); 1372 1373 if (F->getCond()) 1374 KnownVal = TryEvaluateBool(F->getCond()); 1375 1376 // Now create the loop body. 1377 { 1378 assert(F->getBody()); 1379 1380 // Save the current values for Block, Succ, and continue targets. 1381 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1382 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1383 1384 // Create a new block to contain the (bottom) of the loop body. 1385 Block = NULL; 1386 1387 if (Stmt* I = F->getInc()) { 1388 // Generate increment code in its own basic block. This is the target of 1389 // continue statements. 1390 Succ = addStmt(I); 1391 } else { 1392 // No increment code. Create a special, empty, block that is used as the 1393 // target block for "looping back" to the start of the loop. 1394 assert(Succ == EntryConditionBlock); 1395 Succ = createBlock(); 1396 } 1397 1398 // Finish up the increment (or empty) block if it hasn't been already. 1399 if (Block) { 1400 assert(Block == Succ); 1401 if (badCFG) 1402 return 0; 1403 Block = 0; 1404 } 1405 1406 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1407 1408 // The starting block for the loop increment is the block that should 1409 // represent the 'loop target' for looping back to the start of the loop. 1410 ContinueJumpTarget.Block->setLoopTarget(F); 1411 1412 // Now populate the body block, and in the process create new blocks as we 1413 // walk the body of the loop. 1414 CFGBlock* BodyBlock = addStmt(F->getBody()); 1415 1416 if (!BodyBlock) 1417 BodyBlock = ContinueJumpTarget.Block;//can happen for "for (...;...;...);" 1418 else if (badCFG) 1419 return 0; 1420 1421 // This new body block is a successor to our "exit" condition block. 1422 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1423 } 1424 1425 // Link up the condition block with the code that follows the loop. (the 1426 // false branch). 1427 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1428 1429 // If the loop contains initialization, create a new block for those 1430 // statements. This block can also contain statements that precede the loop. 1431 if (Stmt* I = F->getInit()) { 1432 Block = createBlock(); 1433 return addStmt(I); 1434 } else { 1435 // There is no loop initialization. We are thus basically a while loop. 1436 // NULL out Block to force lazy block construction. 1437 Block = NULL; 1438 Succ = EntryConditionBlock; 1439 return EntryConditionBlock; 1440 } 1441} 1442 1443CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1444 if (asc.alwaysAdd()) { 1445 autoCreateBlock(); 1446 AppendStmt(Block, M, asc); 1447 } 1448 return Visit(M->getBase(), 1449 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1450 : AddStmtChoice::AsLValueNotAlwaysAdd); 1451} 1452 1453CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1454 // Objective-C fast enumeration 'for' statements: 1455 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1456 // 1457 // for ( Type newVariable in collection_expression ) { statements } 1458 // 1459 // becomes: 1460 // 1461 // prologue: 1462 // 1. collection_expression 1463 // T. jump to loop_entry 1464 // loop_entry: 1465 // 1. side-effects of element expression 1466 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1467 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1468 // TB: 1469 // statements 1470 // T. jump to loop_entry 1471 // FB: 1472 // what comes after 1473 // 1474 // and 1475 // 1476 // Type existingItem; 1477 // for ( existingItem in expression ) { statements } 1478 // 1479 // becomes: 1480 // 1481 // the same with newVariable replaced with existingItem; the binding works 1482 // the same except that for one ObjCForCollectionStmt::getElement() returns 1483 // a DeclStmt and the other returns a DeclRefExpr. 1484 // 1485 1486 CFGBlock* LoopSuccessor = 0; 1487 1488 if (Block) { 1489 if (badCFG) 1490 return 0; 1491 LoopSuccessor = Block; 1492 Block = 0; 1493 } else 1494 LoopSuccessor = Succ; 1495 1496 // Build the condition blocks. 1497 CFGBlock* ExitConditionBlock = createBlock(false); 1498 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1499 1500 // Set the terminator for the "exit" condition block. 1501 ExitConditionBlock->setTerminator(S); 1502 1503 // The last statement in the block should be the ObjCForCollectionStmt, which 1504 // performs the actual binding to 'element' and determines if there are any 1505 // more items in the collection. 1506 AppendStmt(ExitConditionBlock, S); 1507 Block = ExitConditionBlock; 1508 1509 // Walk the 'element' expression to see if there are any side-effects. We 1510 // generate new blocks as necesary. We DON'T add the statement by default to 1511 // the CFG unless it contains control-flow. 1512 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1513 if (Block) { 1514 if (badCFG) 1515 return 0; 1516 Block = 0; 1517 } 1518 1519 // The condition block is the implicit successor for the loop body as well as 1520 // any code above the loop. 1521 Succ = EntryConditionBlock; 1522 1523 // Now create the true branch. 1524 { 1525 // Save the current values for Succ, continue and break targets. 1526 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1527 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1528 save_break(BreakJumpTarget); 1529 1530 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1531 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1532 1533 CFGBlock* BodyBlock = addStmt(S->getBody()); 1534 1535 if (!BodyBlock) 1536 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1537 else if (Block) { 1538 if (badCFG) 1539 return 0; 1540 } 1541 1542 // This new body block is a successor to our "exit" condition block. 1543 AddSuccessor(ExitConditionBlock, BodyBlock); 1544 } 1545 1546 // Link up the condition block with the code that follows the loop. 1547 // (the false branch). 1548 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1549 1550 // Now create a prologue block to contain the collection expression. 1551 Block = createBlock(); 1552 return addStmt(S->getCollection()); 1553} 1554 1555CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1556 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1557 1558 // Inline the body. 1559 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1560 1561 // The sync body starts its own basic block. This makes it a little easier 1562 // for diagnostic clients. 1563 if (SyncBlock) { 1564 if (badCFG) 1565 return 0; 1566 1567 Block = 0; 1568 Succ = SyncBlock; 1569 } 1570 1571 // Add the @synchronized to the CFG. 1572 autoCreateBlock(); 1573 AppendStmt(Block, S, AddStmtChoice::AlwaysAdd); 1574 1575 // Inline the sync expression. 1576 return addStmt(S->getSynchExpr()); 1577} 1578 1579CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1580 // FIXME 1581 return NYS(); 1582} 1583 1584CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1585 CFGBlock* LoopSuccessor = NULL; 1586 1587 // Save local scope position because in case of condition variable ScopePos 1588 // won't be restored when traversing AST. 1589 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1590 1591 // Create local scope for possible condition variable. 1592 // Store scope position for continue statement. 1593 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1594 if (VarDecl* VD = W->getConditionVariable()) { 1595 addLocalScopeForVarDecl(VD); 1596 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1597 } 1598 1599 // "while" is a control-flow statement. Thus we stop processing the current 1600 // block. 1601 if (Block) { 1602 if (badCFG) 1603 return 0; 1604 LoopSuccessor = Block; 1605 } else 1606 LoopSuccessor = Succ; 1607 1608 // Because of short-circuit evaluation, the condition of the loop can span 1609 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1610 // evaluate the condition. 1611 CFGBlock* ExitConditionBlock = createBlock(false); 1612 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1613 1614 // Set the terminator for the "exit" condition block. 1615 ExitConditionBlock->setTerminator(W); 1616 1617 // Now add the actual condition to the condition block. Because the condition 1618 // itself may contain control-flow, new blocks may be created. Thus we update 1619 // "Succ" after adding the condition. 1620 if (Stmt* C = W->getCond()) { 1621 Block = ExitConditionBlock; 1622 EntryConditionBlock = addStmt(C); 1623 assert(Block == EntryConditionBlock); 1624 1625 // If this block contains a condition variable, add both the condition 1626 // variable and initializer to the CFG. 1627 if (VarDecl *VD = W->getConditionVariable()) { 1628 if (Expr *Init = VD->getInit()) { 1629 autoCreateBlock(); 1630 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1631 EntryConditionBlock = addStmt(Init); 1632 assert(Block == EntryConditionBlock); 1633 } 1634 } 1635 1636 if (Block) { 1637 if (badCFG) 1638 return 0; 1639 } 1640 } 1641 1642 // The condition block is the implicit successor for the loop body as well as 1643 // any code above the loop. 1644 Succ = EntryConditionBlock; 1645 1646 // See if this is a known constant. 1647 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1648 1649 // Process the loop body. 1650 { 1651 assert(W->getBody()); 1652 1653 // Save the current values for Block, Succ, and continue and break targets 1654 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1655 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1656 save_break(BreakJumpTarget); 1657 1658 // Create an empty block to represent the transition block for looping back 1659 // to the head of the loop. 1660 Block = 0; 1661 assert(Succ == EntryConditionBlock); 1662 Succ = createBlock(); 1663 Succ->setLoopTarget(W); 1664 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1665 1666 // All breaks should go to the code following the loop. 1667 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1668 1669 // NULL out Block to force lazy instantiation of blocks for the body. 1670 Block = NULL; 1671 1672 // Loop body should end with destructor of Condition variable (if any). 1673 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1674 1675 // If body is not a compound statement create implicit scope 1676 // and add destructors. 1677 if (!isa<CompoundStmt>(W->getBody())) 1678 addLocalScopeAndDtors(W->getBody()); 1679 1680 // Create the body. The returned block is the entry to the loop body. 1681 CFGBlock* BodyBlock = addStmt(W->getBody()); 1682 1683 if (!BodyBlock) 1684 BodyBlock = ContinueJumpTarget.Block; // can happen for "while(...) ;" 1685 else if (Block) { 1686 if (badCFG) 1687 return 0; 1688 } 1689 1690 // Add the loop body entry as a successor to the condition. 1691 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1692 } 1693 1694 // Link up the condition block with the code that follows the loop. (the 1695 // false branch). 1696 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1697 1698 // There can be no more statements in the condition block since we loop back 1699 // to this block. NULL out Block to force lazy creation of another block. 1700 Block = NULL; 1701 1702 // Return the condition block, which is the dominating block for the loop. 1703 Succ = EntryConditionBlock; 1704 return EntryConditionBlock; 1705} 1706 1707 1708CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1709 // FIXME: For now we pretend that @catch and the code it contains does not 1710 // exit. 1711 return Block; 1712} 1713 1714CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1715 // FIXME: This isn't complete. We basically treat @throw like a return 1716 // statement. 1717 1718 // If we were in the middle of a block we stop processing that block. 1719 if (badCFG) 1720 return 0; 1721 1722 // Create the new block. 1723 Block = createBlock(false); 1724 1725 // The Exit block is the only successor. 1726 AddSuccessor(Block, &cfg->getExit()); 1727 1728 // Add the statement to the block. This may create new blocks if S contains 1729 // control-flow (short-circuit operations). 1730 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1731} 1732 1733CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1734 // If we were in the middle of a block we stop processing that block. 1735 if (badCFG) 1736 return 0; 1737 1738 // Create the new block. 1739 Block = createBlock(false); 1740 1741 if (TryTerminatedBlock) 1742 // The current try statement is the only successor. 1743 AddSuccessor(Block, TryTerminatedBlock); 1744 else 1745 // otherwise the Exit block is the only successor. 1746 AddSuccessor(Block, &cfg->getExit()); 1747 1748 // Add the statement to the block. This may create new blocks if S contains 1749 // control-flow (short-circuit operations). 1750 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1751} 1752 1753CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1754 CFGBlock* LoopSuccessor = NULL; 1755 1756 // "do...while" is a control-flow statement. Thus we stop processing the 1757 // current block. 1758 if (Block) { 1759 if (badCFG) 1760 return 0; 1761 LoopSuccessor = Block; 1762 } else 1763 LoopSuccessor = Succ; 1764 1765 // Because of short-circuit evaluation, the condition of the loop can span 1766 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1767 // evaluate the condition. 1768 CFGBlock* ExitConditionBlock = createBlock(false); 1769 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1770 1771 // Set the terminator for the "exit" condition block. 1772 ExitConditionBlock->setTerminator(D); 1773 1774 // Now add the actual condition to the condition block. Because the condition 1775 // itself may contain control-flow, new blocks may be created. 1776 if (Stmt* C = D->getCond()) { 1777 Block = ExitConditionBlock; 1778 EntryConditionBlock = addStmt(C); 1779 if (Block) { 1780 if (badCFG) 1781 return 0; 1782 } 1783 } 1784 1785 // The condition block is the implicit successor for the loop body. 1786 Succ = EntryConditionBlock; 1787 1788 // See if this is a known constant. 1789 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1790 1791 // Process the loop body. 1792 CFGBlock* BodyBlock = NULL; 1793 { 1794 assert(D->getBody()); 1795 1796 // Save the current values for Block, Succ, and continue and break targets 1797 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1798 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1799 save_break(BreakJumpTarget); 1800 1801 // All continues within this loop should go to the condition block 1802 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1803 1804 // All breaks should go to the code following the loop. 1805 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1806 1807 // NULL out Block to force lazy instantiation of blocks for the body. 1808 Block = NULL; 1809 1810 // If body is not a compound statement create implicit scope 1811 // and add destructors. 1812 if (!isa<CompoundStmt>(D->getBody())) 1813 addLocalScopeAndDtors(D->getBody()); 1814 1815 // Create the body. The returned block is the entry to the loop body. 1816 BodyBlock = addStmt(D->getBody()); 1817 1818 if (!BodyBlock) 1819 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1820 else if (Block) { 1821 if (badCFG) 1822 return 0; 1823 } 1824 1825 if (!KnownVal.isFalse()) { 1826 // Add an intermediate block between the BodyBlock and the 1827 // ExitConditionBlock to represent the "loop back" transition. Create an 1828 // empty block to represent the transition block for looping back to the 1829 // head of the loop. 1830 // FIXME: Can we do this more efficiently without adding another block? 1831 Block = NULL; 1832 Succ = BodyBlock; 1833 CFGBlock *LoopBackBlock = createBlock(); 1834 LoopBackBlock->setLoopTarget(D); 1835 1836 // Add the loop body entry as a successor to the condition. 1837 AddSuccessor(ExitConditionBlock, LoopBackBlock); 1838 } 1839 else 1840 AddSuccessor(ExitConditionBlock, NULL); 1841 } 1842 1843 // Link up the condition block with the code that follows the loop. 1844 // (the false branch). 1845 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1846 1847 // There can be no more statements in the body block(s) since we loop back to 1848 // the body. NULL out Block to force lazy creation of another block. 1849 Block = NULL; 1850 1851 // Return the loop body, which is the dominating block for the loop. 1852 Succ = BodyBlock; 1853 return BodyBlock; 1854} 1855 1856CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1857 // "continue" is a control-flow statement. Thus we stop processing the 1858 // current block. 1859 if (badCFG) 1860 return 0; 1861 1862 // Now create a new block that ends with the continue statement. 1863 Block = createBlock(false); 1864 Block->setTerminator(C); 1865 1866 // If there is no target for the continue, then we are looking at an 1867 // incomplete AST. This means the CFG cannot be constructed. 1868 if (ContinueJumpTarget.Block) { 1869 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.ScopePos, C); 1870 AddSuccessor(Block, ContinueJumpTarget.Block); 1871 } else 1872 badCFG = true; 1873 1874 return Block; 1875} 1876 1877CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1878 AddStmtChoice asc) { 1879 1880 if (asc.alwaysAdd()) { 1881 autoCreateBlock(); 1882 AppendStmt(Block, E); 1883 } 1884 1885 // VLA types have expressions that must be evaluated. 1886 if (E->isArgumentType()) { 1887 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1888 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1889 addStmt(VA->getSizeExpr()); 1890 } 1891 1892 return Block; 1893} 1894 1895/// VisitStmtExpr - Utility method to handle (nested) statement 1896/// expressions (a GCC extension). 1897CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 1898 if (asc.alwaysAdd()) { 1899 autoCreateBlock(); 1900 AppendStmt(Block, SE); 1901 } 1902 return VisitCompoundStmt(SE->getSubStmt()); 1903} 1904 1905CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1906 // "switch" is a control-flow statement. Thus we stop processing the current 1907 // block. 1908 CFGBlock* SwitchSuccessor = NULL; 1909 1910 // Save local scope position because in case of condition variable ScopePos 1911 // won't be restored when traversing AST. 1912 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1913 1914 // Create local scope for possible condition variable. 1915 // Store scope position. Add implicit destructor. 1916 if (VarDecl* VD = Terminator->getConditionVariable()) { 1917 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 1918 addLocalScopeForVarDecl(VD); 1919 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 1920 } 1921 1922 if (Block) { 1923 if (badCFG) 1924 return 0; 1925 SwitchSuccessor = Block; 1926 } else SwitchSuccessor = Succ; 1927 1928 // Save the current "switch" context. 1929 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1930 save_default(DefaultCaseBlock); 1931 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1932 1933 // Set the "default" case to be the block after the switch statement. If the 1934 // switch statement contains a "default:", this value will be overwritten with 1935 // the block for that code. 1936 DefaultCaseBlock = SwitchSuccessor; 1937 1938 // Create a new block that will contain the switch statement. 1939 SwitchTerminatedBlock = createBlock(false); 1940 1941 // Now process the switch body. The code after the switch is the implicit 1942 // successor. 1943 Succ = SwitchSuccessor; 1944 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 1945 1946 // When visiting the body, the case statements should automatically get linked 1947 // up to the switch. We also don't keep a pointer to the body, since all 1948 // control-flow from the switch goes to case/default statements. 1949 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 1950 Block = NULL; 1951 1952 // If body is not a compound statement create implicit scope 1953 // and add destructors. 1954 if (!isa<CompoundStmt>(Terminator->getBody())) 1955 addLocalScopeAndDtors(Terminator->getBody()); 1956 1957 addStmt(Terminator->getBody()); 1958 if (Block) { 1959 if (badCFG) 1960 return 0; 1961 } 1962 1963 // If we have no "default:" case, the default transition is to the code 1964 // following the switch body. 1965 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1966 1967 // Add the terminator and condition in the switch block. 1968 SwitchTerminatedBlock->setTerminator(Terminator); 1969 assert(Terminator->getCond() && "switch condition must be non-NULL"); 1970 Block = SwitchTerminatedBlock; 1971 Block = addStmt(Terminator->getCond()); 1972 1973 // Finally, if the SwitchStmt contains a condition variable, add both the 1974 // SwitchStmt and the condition variable initialization to the CFG. 1975 if (VarDecl *VD = Terminator->getConditionVariable()) { 1976 if (Expr *Init = VD->getInit()) { 1977 autoCreateBlock(); 1978 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 1979 addStmt(Init); 1980 } 1981 } 1982 1983 return Block; 1984} 1985 1986CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1987 // CaseStmts are essentially labels, so they are the first statement in a 1988 // block. 1989 CFGBlock *TopBlock = 0, *LastBlock = 0; 1990 1991 if (Stmt *Sub = CS->getSubStmt()) { 1992 // For deeply nested chains of CaseStmts, instead of doing a recursion 1993 // (which can blow out the stack), manually unroll and create blocks 1994 // along the way. 1995 while (isa<CaseStmt>(Sub)) { 1996 CFGBlock *CurrentBlock = createBlock(false); 1997 CurrentBlock->setLabel(CS); 1998 1999 if (TopBlock) 2000 AddSuccessor(LastBlock, CurrentBlock); 2001 else 2002 TopBlock = CurrentBlock; 2003 2004 AddSuccessor(SwitchTerminatedBlock, CurrentBlock); 2005 LastBlock = CurrentBlock; 2006 2007 CS = cast<CaseStmt>(Sub); 2008 Sub = CS->getSubStmt(); 2009 } 2010 2011 addStmt(Sub); 2012 } 2013 2014 CFGBlock* CaseBlock = Block; 2015 if (!CaseBlock) 2016 CaseBlock = createBlock(); 2017 2018 // Cases statements partition blocks, so this is the top of the basic block we 2019 // were processing (the "case XXX:" is the label). 2020 CaseBlock->setLabel(CS); 2021 2022 if (badCFG) 2023 return 0; 2024 2025 // Add this block to the list of successors for the block with the switch 2026 // statement. 2027 assert(SwitchTerminatedBlock); 2028 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 2029 2030 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2031 Block = NULL; 2032 2033 if (TopBlock) { 2034 AddSuccessor(LastBlock, CaseBlock); 2035 Succ = TopBlock; 2036 } 2037 else { 2038 // This block is now the implicit successor of other blocks. 2039 Succ = CaseBlock; 2040 } 2041 2042 return Succ; 2043} 2044 2045CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2046 if (Terminator->getSubStmt()) 2047 addStmt(Terminator->getSubStmt()); 2048 2049 DefaultCaseBlock = Block; 2050 2051 if (!DefaultCaseBlock) 2052 DefaultCaseBlock = createBlock(); 2053 2054 // Default statements partition blocks, so this is the top of the basic block 2055 // we were processing (the "default:" is the label). 2056 DefaultCaseBlock->setLabel(Terminator); 2057 2058 if (badCFG) 2059 return 0; 2060 2061 // Unlike case statements, we don't add the default block to the successors 2062 // for the switch statement immediately. This is done when we finish 2063 // processing the switch statement. This allows for the default case 2064 // (including a fall-through to the code after the switch statement) to always 2065 // be the last successor of a switch-terminated block. 2066 2067 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2068 Block = NULL; 2069 2070 // This block is now the implicit successor of other blocks. 2071 Succ = DefaultCaseBlock; 2072 2073 return DefaultCaseBlock; 2074} 2075 2076CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2077 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2078 // current block. 2079 CFGBlock* TrySuccessor = NULL; 2080 2081 if (Block) { 2082 if (badCFG) 2083 return 0; 2084 TrySuccessor = Block; 2085 } else TrySuccessor = Succ; 2086 2087 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2088 2089 // Create a new block that will contain the try statement. 2090 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2091 // Add the terminator in the try block. 2092 NewTryTerminatedBlock->setTerminator(Terminator); 2093 2094 bool HasCatchAll = false; 2095 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2096 // The code after the try is the implicit successor. 2097 Succ = TrySuccessor; 2098 CXXCatchStmt *CS = Terminator->getHandler(h); 2099 if (CS->getExceptionDecl() == 0) { 2100 HasCatchAll = true; 2101 } 2102 Block = NULL; 2103 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2104 if (CatchBlock == 0) 2105 return 0; 2106 // Add this block to the list of successors for the block with the try 2107 // statement. 2108 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 2109 } 2110 if (!HasCatchAll) { 2111 if (PrevTryTerminatedBlock) 2112 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2113 else 2114 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2115 } 2116 2117 // The code after the try is the implicit successor. 2118 Succ = TrySuccessor; 2119 2120 // Save the current "try" context. 2121 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2122 TryTerminatedBlock = NewTryTerminatedBlock; 2123 2124 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2125 Block = NULL; 2126 Block = addStmt(Terminator->getTryBlock()); 2127 return Block; 2128} 2129 2130CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2131 // CXXCatchStmt are treated like labels, so they are the first statement in a 2132 // block. 2133 2134 if (CS->getHandlerBlock()) 2135 addStmt(CS->getHandlerBlock()); 2136 2137 CFGBlock* CatchBlock = Block; 2138 if (!CatchBlock) 2139 CatchBlock = createBlock(); 2140 2141 CatchBlock->setLabel(CS); 2142 2143 if (badCFG) 2144 return 0; 2145 2146 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2147 Block = NULL; 2148 2149 return CatchBlock; 2150} 2151 2152CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2153 AddStmtChoice asc) { 2154 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 2155 : AddStmtChoice::AlwaysAdd; 2156 autoCreateBlock(); 2157 AppendStmt(Block, C, AddStmtChoice(K)); 2158 return VisitChildren(C); 2159} 2160 2161CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2162 // Lazily create the indirect-goto dispatch block if there isn't one already. 2163 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2164 2165 if (!IBlock) { 2166 IBlock = createBlock(false); 2167 cfg->setIndirectGotoBlock(IBlock); 2168 } 2169 2170 // IndirectGoto is a control-flow statement. Thus we stop processing the 2171 // current block and create a new one. 2172 if (badCFG) 2173 return 0; 2174 2175 Block = createBlock(false); 2176 Block->setTerminator(I); 2177 AddSuccessor(Block, IBlock); 2178 return addStmt(I->getTarget()); 2179} 2180 2181} // end anonymous namespace 2182 2183/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2184/// no successors or predecessors. If this is the first block created in the 2185/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2186CFGBlock* CFG::createBlock() { 2187 bool first_block = begin() == end(); 2188 2189 // Create the block. 2190 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2191 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2192 Blocks.push_back(Mem, BlkBVC); 2193 2194 // If this is the first block, set it as the Entry and Exit. 2195 if (first_block) 2196 Entry = Exit = &back(); 2197 2198 // Return the block. 2199 return &back(); 2200} 2201 2202/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2203/// CFG is returned to the caller. 2204CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2205 BuildOptions BO) { 2206 CFGBuilder Builder; 2207 return Builder.buildCFG(D, Statement, C, BO); 2208} 2209 2210//===----------------------------------------------------------------------===// 2211// CFG: Queries for BlkExprs. 2212//===----------------------------------------------------------------------===// 2213 2214namespace { 2215 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2216} 2217 2218static void FindSubExprAssignments(Stmt *S, 2219 llvm::SmallPtrSet<Expr*,50>& Set) { 2220 if (!S) 2221 return; 2222 2223 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 2224 Stmt *child = *I; 2225 if (!child) 2226 continue; 2227 2228 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2229 if (B->isAssignmentOp()) Set.insert(B); 2230 2231 FindSubExprAssignments(child, Set); 2232 } 2233} 2234 2235static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2236 BlkExprMapTy* M = new BlkExprMapTy(); 2237 2238 // Look for assignments that are used as subexpressions. These are the only 2239 // assignments that we want to *possibly* register as a block-level 2240 // expression. Basically, if an assignment occurs both in a subexpression and 2241 // at the block-level, it is a block-level expression. 2242 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2243 2244 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2245 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2246 if (CFGStmt S = BI->getAs<CFGStmt>()) 2247 FindSubExprAssignments(S, SubExprAssignments); 2248 2249 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2250 2251 // Iterate over the statements again on identify the Expr* and Stmt* at the 2252 // block-level that are block-level expressions. 2253 2254 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2255 CFGStmt CS = BI->getAs<CFGStmt>(); 2256 if (!CS.isValid()) 2257 continue; 2258 if (Expr* Exp = dyn_cast<Expr>(CS.getStmt())) { 2259 2260 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2261 // Assignment expressions that are not nested within another 2262 // expression are really "statements" whose value is never used by 2263 // another expression. 2264 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2265 continue; 2266 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2267 // Special handling for statement expressions. The last statement in 2268 // the statement expression is also a block-level expr. 2269 const CompoundStmt* C = Terminator->getSubStmt(); 2270 if (!C->body_empty()) { 2271 unsigned x = M->size(); 2272 (*M)[C->body_back()] = x; 2273 } 2274 } 2275 2276 unsigned x = M->size(); 2277 (*M)[Exp] = x; 2278 } 2279 } 2280 2281 // Look at terminators. The condition is a block-level expression. 2282 2283 Stmt* S = (*I)->getTerminatorCondition(); 2284 2285 if (S && M->find(S) == M->end()) { 2286 unsigned x = M->size(); 2287 (*M)[S] = x; 2288 } 2289 } 2290 2291 return M; 2292} 2293 2294CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2295 assert(S != NULL); 2296 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2297 2298 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2299 BlkExprMapTy::iterator I = M->find(S); 2300 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2301} 2302 2303unsigned CFG::getNumBlkExprs() { 2304 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2305 return M->size(); 2306 else { 2307 // We assume callers interested in the number of BlkExprs will want 2308 // the map constructed if it doesn't already exist. 2309 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2310 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2311 } 2312} 2313 2314//===----------------------------------------------------------------------===// 2315// Filtered walking of the CFG. 2316//===----------------------------------------------------------------------===// 2317 2318bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2319 const CFGBlock *From, const CFGBlock *To) { 2320 2321 if (F.IgnoreDefaultsWithCoveredEnums) { 2322 // If the 'To' has no label or is labeled but the label isn't a 2323 // CaseStmt then filter this edge. 2324 if (const SwitchStmt *S = 2325 dyn_cast_or_null<SwitchStmt>(From->getTerminator())) { 2326 if (S->isAllEnumCasesCovered()) { 2327 const Stmt *L = To->getLabel(); 2328 if (!L || !isa<CaseStmt>(L)) 2329 return true; 2330 } 2331 } 2332 } 2333 2334 return false; 2335} 2336 2337//===----------------------------------------------------------------------===// 2338// Cleanup: CFG dstor. 2339//===----------------------------------------------------------------------===// 2340 2341CFG::~CFG() { 2342 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2343} 2344 2345//===----------------------------------------------------------------------===// 2346// CFG pretty printing 2347//===----------------------------------------------------------------------===// 2348 2349namespace { 2350 2351class StmtPrinterHelper : public PrinterHelper { 2352 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2353 typedef llvm::DenseMap<Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2354 StmtMapTy StmtMap; 2355 DeclMapTy DeclMap; 2356 signed CurrentBlock; 2357 unsigned CurrentStmt; 2358 const LangOptions &LangOpts; 2359public: 2360 2361 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2362 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 2363 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2364 unsigned j = 1; 2365 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2366 BI != BEnd; ++BI, ++j ) { 2367 if (CFGStmt SE = BI->getAs<CFGStmt>()) { 2368 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2369 StmtMap[SE] = P; 2370 2371 if (DeclStmt* DS = dyn_cast<DeclStmt>(SE.getStmt())) { 2372 DeclMap[DS->getSingleDecl()] = P; 2373 2374 } else if (IfStmt* IS = dyn_cast<IfStmt>(SE.getStmt())) { 2375 if (VarDecl* VD = IS->getConditionVariable()) 2376 DeclMap[VD] = P; 2377 2378 } else if (ForStmt* FS = dyn_cast<ForStmt>(SE.getStmt())) { 2379 if (VarDecl* VD = FS->getConditionVariable()) 2380 DeclMap[VD] = P; 2381 2382 } else if (WhileStmt* WS = dyn_cast<WhileStmt>(SE.getStmt())) { 2383 if (VarDecl* VD = WS->getConditionVariable()) 2384 DeclMap[VD] = P; 2385 2386 } else if (SwitchStmt* SS = dyn_cast<SwitchStmt>(SE.getStmt())) { 2387 if (VarDecl* VD = SS->getConditionVariable()) 2388 DeclMap[VD] = P; 2389 2390 } else if (CXXCatchStmt* CS = dyn_cast<CXXCatchStmt>(SE.getStmt())) { 2391 if (VarDecl* VD = CS->getExceptionDecl()) 2392 DeclMap[VD] = P; 2393 } 2394 } 2395 } 2396 } 2397 } 2398 2399 virtual ~StmtPrinterHelper() {} 2400 2401 const LangOptions &getLangOpts() const { return LangOpts; } 2402 void setBlockID(signed i) { CurrentBlock = i; } 2403 void setStmtID(unsigned i) { CurrentStmt = i; } 2404 2405 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 2406 StmtMapTy::iterator I = StmtMap.find(S); 2407 2408 if (I == StmtMap.end()) 2409 return false; 2410 2411 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2412 && I->second.second == CurrentStmt) { 2413 return false; 2414 } 2415 2416 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2417 return true; 2418 } 2419 2420 bool handleDecl(Decl* D, llvm::raw_ostream& OS) { 2421 DeclMapTy::iterator I = DeclMap.find(D); 2422 2423 if (I == DeclMap.end()) 2424 return false; 2425 2426 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 2427 && I->second.second == CurrentStmt) { 2428 return false; 2429 } 2430 2431 OS << "[B" << I->second.first << "." << I->second.second << "]"; 2432 return true; 2433 } 2434}; 2435} // end anonymous namespace 2436 2437 2438namespace { 2439class CFGBlockTerminatorPrint 2440 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 2441 2442 llvm::raw_ostream& OS; 2443 StmtPrinterHelper* Helper; 2444 PrintingPolicy Policy; 2445public: 2446 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 2447 const PrintingPolicy &Policy) 2448 : OS(os), Helper(helper), Policy(Policy) {} 2449 2450 void VisitIfStmt(IfStmt* I) { 2451 OS << "if "; 2452 I->getCond()->printPretty(OS,Helper,Policy); 2453 } 2454 2455 // Default case. 2456 void VisitStmt(Stmt* Terminator) { 2457 Terminator->printPretty(OS, Helper, Policy); 2458 } 2459 2460 void VisitForStmt(ForStmt* F) { 2461 OS << "for (" ; 2462 if (F->getInit()) 2463 OS << "..."; 2464 OS << "; "; 2465 if (Stmt* C = F->getCond()) 2466 C->printPretty(OS, Helper, Policy); 2467 OS << "; "; 2468 if (F->getInc()) 2469 OS << "..."; 2470 OS << ")"; 2471 } 2472 2473 void VisitWhileStmt(WhileStmt* W) { 2474 OS << "while " ; 2475 if (Stmt* C = W->getCond()) 2476 C->printPretty(OS, Helper, Policy); 2477 } 2478 2479 void VisitDoStmt(DoStmt* D) { 2480 OS << "do ... while "; 2481 if (Stmt* C = D->getCond()) 2482 C->printPretty(OS, Helper, Policy); 2483 } 2484 2485 void VisitSwitchStmt(SwitchStmt* Terminator) { 2486 OS << "switch "; 2487 Terminator->getCond()->printPretty(OS, Helper, Policy); 2488 } 2489 2490 void VisitCXXTryStmt(CXXTryStmt* CS) { 2491 OS << "try ..."; 2492 } 2493 2494 void VisitConditionalOperator(ConditionalOperator* C) { 2495 C->getCond()->printPretty(OS, Helper, Policy); 2496 OS << " ? ... : ..."; 2497 } 2498 2499 void VisitChooseExpr(ChooseExpr* C) { 2500 OS << "__builtin_choose_expr( "; 2501 C->getCond()->printPretty(OS, Helper, Policy); 2502 OS << " )"; 2503 } 2504 2505 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2506 OS << "goto *"; 2507 I->getTarget()->printPretty(OS, Helper, Policy); 2508 } 2509 2510 void VisitBinaryOperator(BinaryOperator* B) { 2511 if (!B->isLogicalOp()) { 2512 VisitExpr(B); 2513 return; 2514 } 2515 2516 B->getLHS()->printPretty(OS, Helper, Policy); 2517 2518 switch (B->getOpcode()) { 2519 case BO_LOr: 2520 OS << " || ..."; 2521 return; 2522 case BO_LAnd: 2523 OS << " && ..."; 2524 return; 2525 default: 2526 assert(false && "Invalid logical operator."); 2527 } 2528 } 2529 2530 void VisitExpr(Expr* E) { 2531 E->printPretty(OS, Helper, Policy); 2532 } 2533}; 2534} // end anonymous namespace 2535 2536static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2537 const CFGElement &E) { 2538 if (CFGStmt CS = E.getAs<CFGStmt>()) { 2539 Stmt *S = CS; 2540 2541 if (Helper) { 2542 2543 // special printing for statement-expressions. 2544 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 2545 CompoundStmt* Sub = SE->getSubStmt(); 2546 2547 if (Sub->child_begin() != Sub->child_end()) { 2548 OS << "({ ... ; "; 2549 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2550 OS << " })\n"; 2551 return; 2552 } 2553 } 2554 // special printing for comma expressions. 2555 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 2556 if (B->getOpcode() == BO_Comma) { 2557 OS << "... , "; 2558 Helper->handledStmt(B->getRHS(),OS); 2559 OS << '\n'; 2560 return; 2561 } 2562 } 2563 } 2564 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2565 2566 if (isa<CXXOperatorCallExpr>(S)) { 2567 OS << " (OperatorCall)"; 2568 } 2569 else if (isa<CXXBindTemporaryExpr>(S)) { 2570 OS << " (BindTemporary)"; 2571 } 2572 2573 // Expressions need a newline. 2574 if (isa<Expr>(S)) 2575 OS << '\n'; 2576 2577 } else if (CFGInitializer IE = E.getAs<CFGInitializer>()) { 2578 CXXBaseOrMemberInitializer* I = IE; 2579 if (I->isBaseInitializer()) 2580 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 2581 else OS << I->getMember()->getName(); 2582 2583 OS << "("; 2584 if (Expr* IE = I->getInit()) 2585 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2586 OS << ")"; 2587 2588 if (I->isBaseInitializer()) 2589 OS << " (Base initializer)\n"; 2590 else OS << " (Member initializer)\n"; 2591 2592 } else if (CFGAutomaticObjDtor DE = E.getAs<CFGAutomaticObjDtor>()){ 2593 VarDecl* VD = DE.getVarDecl(); 2594 Helper->handleDecl(VD, OS); 2595 2596 Type* T = VD->getType().getTypePtr(); 2597 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 2598 T = RT->getPointeeType().getTypePtr(); 2599 2600 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 2601 OS << " (Implicit destructor)\n"; 2602 } 2603 } 2604 2605static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2606 const CFGBlock& B, 2607 StmtPrinterHelper* Helper, bool print_edges) { 2608 2609 if (Helper) Helper->setBlockID(B.getBlockID()); 2610 2611 // Print the header. 2612 OS << "\n [ B" << B.getBlockID(); 2613 2614 if (&B == &cfg->getEntry()) 2615 OS << " (ENTRY) ]\n"; 2616 else if (&B == &cfg->getExit()) 2617 OS << " (EXIT) ]\n"; 2618 else if (&B == cfg->getIndirectGotoBlock()) 2619 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2620 else 2621 OS << " ]\n"; 2622 2623 // Print the label of this block. 2624 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2625 2626 if (print_edges) 2627 OS << " "; 2628 2629 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2630 OS << L->getName(); 2631 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2632 OS << "case "; 2633 C->getLHS()->printPretty(OS, Helper, 2634 PrintingPolicy(Helper->getLangOpts())); 2635 if (C->getRHS()) { 2636 OS << " ... "; 2637 C->getRHS()->printPretty(OS, Helper, 2638 PrintingPolicy(Helper->getLangOpts())); 2639 } 2640 } else if (isa<DefaultStmt>(Label)) 2641 OS << "default"; 2642 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2643 OS << "catch ("; 2644 if (CS->getExceptionDecl()) 2645 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2646 0); 2647 else 2648 OS << "..."; 2649 OS << ")"; 2650 2651 } else 2652 assert(false && "Invalid label statement in CFGBlock."); 2653 2654 OS << ":\n"; 2655 } 2656 2657 // Iterate through the statements in the block and print them. 2658 unsigned j = 1; 2659 2660 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2661 I != E ; ++I, ++j ) { 2662 2663 // Print the statement # in the basic block and the statement itself. 2664 if (print_edges) 2665 OS << " "; 2666 2667 OS << llvm::format("%3d", j) << ": "; 2668 2669 if (Helper) 2670 Helper->setStmtID(j); 2671 2672 print_elem(OS,Helper,*I); 2673 } 2674 2675 // Print the terminator of this block. 2676 if (B.getTerminator()) { 2677 if (print_edges) 2678 OS << " "; 2679 2680 OS << " T: "; 2681 2682 if (Helper) Helper->setBlockID(-1); 2683 2684 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2685 PrintingPolicy(Helper->getLangOpts())); 2686 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2687 OS << '\n'; 2688 } 2689 2690 if (print_edges) { 2691 // Print the predecessors of this block. 2692 OS << " Predecessors (" << B.pred_size() << "):"; 2693 unsigned i = 0; 2694 2695 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2696 I != E; ++I, ++i) { 2697 2698 if (i == 8 || (i-8) == 0) 2699 OS << "\n "; 2700 2701 OS << " B" << (*I)->getBlockID(); 2702 } 2703 2704 OS << '\n'; 2705 2706 // Print the successors of this block. 2707 OS << " Successors (" << B.succ_size() << "):"; 2708 i = 0; 2709 2710 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2711 I != E; ++I, ++i) { 2712 2713 if (i == 8 || (i-8) % 10 == 0) 2714 OS << "\n "; 2715 2716 if (*I) 2717 OS << " B" << (*I)->getBlockID(); 2718 else 2719 OS << " NULL"; 2720 } 2721 2722 OS << '\n'; 2723 } 2724} 2725 2726 2727/// dump - A simple pretty printer of a CFG that outputs to stderr. 2728void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2729 2730/// print - A simple pretty printer of a CFG that outputs to an ostream. 2731void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2732 StmtPrinterHelper Helper(this, LO); 2733 2734 // Print the entry block. 2735 print_block(OS, this, getEntry(), &Helper, true); 2736 2737 // Iterate through the CFGBlocks and print them one by one. 2738 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2739 // Skip the entry block, because we already printed it. 2740 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2741 continue; 2742 2743 print_block(OS, this, **I, &Helper, true); 2744 } 2745 2746 // Print the exit block. 2747 print_block(OS, this, getExit(), &Helper, true); 2748 OS.flush(); 2749} 2750 2751/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2752void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2753 print(llvm::errs(), cfg, LO); 2754} 2755 2756/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2757/// Generally this will only be called from CFG::print. 2758void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2759 const LangOptions &LO) const { 2760 StmtPrinterHelper Helper(cfg, LO); 2761 print_block(OS, cfg, *this, &Helper, true); 2762} 2763 2764/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2765void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2766 const LangOptions &LO) const { 2767 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2768 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2769} 2770 2771Stmt* CFGBlock::getTerminatorCondition() { 2772 2773 if (!Terminator) 2774 return NULL; 2775 2776 Expr* E = NULL; 2777 2778 switch (Terminator->getStmtClass()) { 2779 default: 2780 break; 2781 2782 case Stmt::ForStmtClass: 2783 E = cast<ForStmt>(Terminator)->getCond(); 2784 break; 2785 2786 case Stmt::WhileStmtClass: 2787 E = cast<WhileStmt>(Terminator)->getCond(); 2788 break; 2789 2790 case Stmt::DoStmtClass: 2791 E = cast<DoStmt>(Terminator)->getCond(); 2792 break; 2793 2794 case Stmt::IfStmtClass: 2795 E = cast<IfStmt>(Terminator)->getCond(); 2796 break; 2797 2798 case Stmt::ChooseExprClass: 2799 E = cast<ChooseExpr>(Terminator)->getCond(); 2800 break; 2801 2802 case Stmt::IndirectGotoStmtClass: 2803 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2804 break; 2805 2806 case Stmt::SwitchStmtClass: 2807 E = cast<SwitchStmt>(Terminator)->getCond(); 2808 break; 2809 2810 case Stmt::ConditionalOperatorClass: 2811 E = cast<ConditionalOperator>(Terminator)->getCond(); 2812 break; 2813 2814 case Stmt::BinaryOperatorClass: // '&&' and '||' 2815 E = cast<BinaryOperator>(Terminator)->getLHS(); 2816 break; 2817 2818 case Stmt::ObjCForCollectionStmtClass: 2819 return Terminator; 2820 } 2821 2822 return E ? E->IgnoreParens() : NULL; 2823} 2824 2825bool CFGBlock::hasBinaryBranchTerminator() const { 2826 2827 if (!Terminator) 2828 return false; 2829 2830 Expr* E = NULL; 2831 2832 switch (Terminator->getStmtClass()) { 2833 default: 2834 return false; 2835 2836 case Stmt::ForStmtClass: 2837 case Stmt::WhileStmtClass: 2838 case Stmt::DoStmtClass: 2839 case Stmt::IfStmtClass: 2840 case Stmt::ChooseExprClass: 2841 case Stmt::ConditionalOperatorClass: 2842 case Stmt::BinaryOperatorClass: 2843 return true; 2844 } 2845 2846 return E ? E->IgnoreParens() : NULL; 2847} 2848 2849 2850//===----------------------------------------------------------------------===// 2851// CFG Graphviz Visualization 2852//===----------------------------------------------------------------------===// 2853 2854 2855#ifndef NDEBUG 2856static StmtPrinterHelper* GraphHelper; 2857#endif 2858 2859void CFG::viewCFG(const LangOptions &LO) const { 2860#ifndef NDEBUG 2861 StmtPrinterHelper H(this, LO); 2862 GraphHelper = &H; 2863 llvm::ViewGraph(this,"CFG"); 2864 GraphHelper = NULL; 2865#endif 2866} 2867 2868namespace llvm { 2869template<> 2870struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2871 2872 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2873 2874 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 2875 2876#ifndef NDEBUG 2877 std::string OutSStr; 2878 llvm::raw_string_ostream Out(OutSStr); 2879 print_block(Out,Graph, *Node, GraphHelper, false); 2880 std::string& OutStr = Out.str(); 2881 2882 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2883 2884 // Process string output to make it nicer... 2885 for (unsigned i = 0; i != OutStr.length(); ++i) 2886 if (OutStr[i] == '\n') { // Left justify 2887 OutStr[i] = '\\'; 2888 OutStr.insert(OutStr.begin()+i+1, 'l'); 2889 } 2890 2891 return OutStr; 2892#else 2893 return ""; 2894#endif 2895 } 2896}; 2897} // end namespace llvm 2898