1 //===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // 10 // This file defines the CFG and CFGBuilder classes for representing and 11 // building Control-Flow Graphs (CFGs) from ASTs. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "clang/Analysis/CFG.h" 16 #include "clang/AST/ASTContext.h" 17 #include "clang/AST/Attr.h" 18 #include "clang/AST/CharUnits.h" 19 #include "clang/AST/DeclCXX.h" 20 #include "clang/AST/PrettyPrinter.h" 21 #include "clang/AST/StmtVisitor.h" 22 #include "llvm/ADT/DenseMap.h" 23 #include "llvm/ADT/OwningPtr.h" 24 #include "llvm/ADT/SmallPtrSet.h" 25 #include "llvm/Support/Allocator.h" 26 #include "llvm/Support/Format.h" 27 #include "llvm/Support/GraphWriter.h" 28 #include "llvm/Support/SaveAndRestore.h" 29 30 using namespace clang; 31 32 namespace { 33 34 static SourceLocation GetEndLoc(Decl *D) { 35 if (VarDecl *VD = dyn_cast<VarDecl>(D)) 36 if (Expr *Ex = VD->getInit()) 37 return Ex->getSourceRange().getEnd(); 38 return D->getLocation(); 39 } 40 41 class CFGBuilder; 42 43 /// The CFG builder uses a recursive algorithm to build the CFG. When 44 /// we process an expression, sometimes we know that we must add the 45 /// subexpressions as block-level expressions. For example: 46 /// 47 /// exp1 || exp2 48 /// 49 /// When processing the '||' expression, we know that exp1 and exp2 50 /// need to be added as block-level expressions, even though they 51 /// might not normally need to be. AddStmtChoice records this 52 /// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 53 /// the builder has an option not to add a subexpression as a 54 /// block-level expression. 55 /// 56 class AddStmtChoice { 57 public: 58 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 59 60 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 61 62 bool alwaysAdd(CFGBuilder &builder, 63 const Stmt *stmt) const; 64 65 /// Return a copy of this object, except with the 'always-add' bit 66 /// set as specified. 67 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 68 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 69 } 70 71 private: 72 Kind kind; 73 }; 74 75 /// LocalScope - Node in tree of local scopes created for C++ implicit 76 /// destructor calls generation. It contains list of automatic variables 77 /// declared in the scope and link to position in previous scope this scope 78 /// began in. 79 /// 80 /// The process of creating local scopes is as follows: 81 /// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 82 /// - Before processing statements in scope (e.g. CompoundStmt) create 83 /// LocalScope object using CFGBuilder::ScopePos as link to previous scope 84 /// and set CFGBuilder::ScopePos to the end of new scope, 85 /// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 86 /// at this VarDecl, 87 /// - For every normal (without jump) end of scope add to CFGBlock destructors 88 /// for objects in the current scope, 89 /// - For every jump add to CFGBlock destructors for objects 90 /// between CFGBuilder::ScopePos and local scope position saved for jump 91 /// target. Thanks to C++ restrictions on goto jumps we can be sure that 92 /// jump target position will be on the path to root from CFGBuilder::ScopePos 93 /// (adding any variable that doesn't need constructor to be called to 94 /// LocalScope can break this assumption), 95 /// 96 class LocalScope { 97 public: 98 typedef BumpVector<VarDecl*> AutomaticVarsTy; 99 100 /// const_iterator - Iterates local scope backwards and jumps to previous 101 /// scope on reaching the beginning of currently iterated scope. 102 class const_iterator { 103 const LocalScope* Scope; 104 105 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 106 /// Invalid iterator (with null Scope) has VarIter equal to 0. 107 unsigned VarIter; 108 109 public: 110 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 111 /// Incrementing invalid iterator is allowed and will result in invalid 112 /// iterator. 113 const_iterator() 114 : Scope(NULL), VarIter(0) {} 115 116 /// Create valid iterator. In case when S.Prev is an invalid iterator and 117 /// I is equal to 0, this will create invalid iterator. 118 const_iterator(const LocalScope& S, unsigned I) 119 : Scope(&S), VarIter(I) { 120 // Iterator to "end" of scope is not allowed. Handle it by going up 121 // in scopes tree possibly up to invalid iterator in the root. 122 if (VarIter == 0 && Scope) 123 *this = Scope->Prev; 124 } 125 126 VarDecl *const* operator->() const { 127 assert (Scope && "Dereferencing invalid iterator is not allowed"); 128 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 129 return &Scope->Vars[VarIter - 1]; 130 } 131 VarDecl *operator*() const { 132 return *this->operator->(); 133 } 134 135 const_iterator &operator++() { 136 if (!Scope) 137 return *this; 138 139 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 140 --VarIter; 141 if (VarIter == 0) 142 *this = Scope->Prev; 143 return *this; 144 } 145 const_iterator operator++(int) { 146 const_iterator P = *this; 147 ++*this; 148 return P; 149 } 150 151 bool operator==(const const_iterator &rhs) const { 152 return Scope == rhs.Scope && VarIter == rhs.VarIter; 153 } 154 bool operator!=(const const_iterator &rhs) const { 155 return !(*this == rhs); 156 } 157 158 operator bool() const { 159 return *this != const_iterator(); 160 } 161 162 int distance(const_iterator L); 163 }; 164 165 friend class const_iterator; 166 167 private: 168 BumpVectorContext ctx; 169 170 /// Automatic variables in order of declaration. 171 AutomaticVarsTy Vars; 172 /// Iterator to variable in previous scope that was declared just before 173 /// begin of this scope. 174 const_iterator Prev; 175 176 public: 177 /// Constructs empty scope linked to previous scope in specified place. 178 LocalScope(BumpVectorContext &ctx, const_iterator P) 179 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 180 181 /// Begin of scope in direction of CFG building (backwards). 182 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 183 184 void addVar(VarDecl *VD) { 185 Vars.push_back(VD, ctx); 186 } 187 }; 188 189 /// distance - Calculates distance from this to L. L must be reachable from this 190 /// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 191 /// number of scopes between this and L. 192 int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 193 int D = 0; 194 const_iterator F = *this; 195 while (F.Scope != L.Scope) { 196 assert (F != const_iterator() 197 && "L iterator is not reachable from F iterator."); 198 D += F.VarIter; 199 F = F.Scope->Prev; 200 } 201 D += F.VarIter - L.VarIter; 202 return D; 203 } 204 205 /// BlockScopePosPair - Structure for specifying position in CFG during its 206 /// build process. It consists of CFGBlock that specifies position in CFG graph 207 /// and LocalScope::const_iterator that specifies position in LocalScope graph. 208 struct BlockScopePosPair { 209 BlockScopePosPair() : block(0) {} 210 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos) 211 : block(b), scopePosition(scopePos) {} 212 213 CFGBlock *block; 214 LocalScope::const_iterator scopePosition; 215 }; 216 217 /// TryResult - a class representing a variant over the values 218 /// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 219 /// and is used by the CFGBuilder to decide if a branch condition 220 /// can be decided up front during CFG construction. 221 class TryResult { 222 int X; 223 public: 224 TryResult(bool b) : X(b ? 1 : 0) {} 225 TryResult() : X(-1) {} 226 227 bool isTrue() const { return X == 1; } 228 bool isFalse() const { return X == 0; } 229 bool isKnown() const { return X >= 0; } 230 void negate() { 231 assert(isKnown()); 232 X ^= 0x1; 233 } 234 }; 235 236 class reverse_children { 237 llvm::SmallVector<Stmt *, 12> childrenBuf; 238 ArrayRef<Stmt*> children; 239 public: 240 reverse_children(Stmt *S); 241 242 typedef ArrayRef<Stmt*>::reverse_iterator iterator; 243 iterator begin() const { return children.rbegin(); } 244 iterator end() const { return children.rend(); } 245 }; 246 247 248 reverse_children::reverse_children(Stmt *S) { 249 if (CallExpr *CE = dyn_cast<CallExpr>(S)) { 250 children = CE->getRawSubExprs(); 251 return; 252 } 253 switch (S->getStmtClass()) { 254 // Note: Fill in this switch with more cases we want to optimize. 255 case Stmt::InitListExprClass: { 256 InitListExpr *IE = cast<InitListExpr>(S); 257 children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()), 258 IE->getNumInits()); 259 return; 260 } 261 default: 262 break; 263 } 264 265 // Default case for all other statements. 266 for (Stmt::child_range I = S->children(); I; ++I) { 267 childrenBuf.push_back(*I); 268 } 269 270 // This needs to be done *after* childrenBuf has been populated. 271 children = childrenBuf; 272 } 273 274 /// CFGBuilder - This class implements CFG construction from an AST. 275 /// The builder is stateful: an instance of the builder should be used to only 276 /// construct a single CFG. 277 /// 278 /// Example usage: 279 /// 280 /// CFGBuilder builder; 281 /// CFG* cfg = builder.BuildAST(stmt1); 282 /// 283 /// CFG construction is done via a recursive walk of an AST. We actually parse 284 /// the AST in reverse order so that the successor of a basic block is 285 /// constructed prior to its predecessor. This allows us to nicely capture 286 /// implicit fall-throughs without extra basic blocks. 287 /// 288 class CFGBuilder { 289 typedef BlockScopePosPair JumpTarget; 290 typedef BlockScopePosPair JumpSource; 291 292 ASTContext *Context; 293 OwningPtr<CFG> cfg; 294 295 CFGBlock *Block; 296 CFGBlock *Succ; 297 JumpTarget ContinueJumpTarget; 298 JumpTarget BreakJumpTarget; 299 CFGBlock *SwitchTerminatedBlock; 300 CFGBlock *DefaultCaseBlock; 301 CFGBlock *TryTerminatedBlock; 302 303 // Current position in local scope. 304 LocalScope::const_iterator ScopePos; 305 306 // LabelMap records the mapping from Label expressions to their jump targets. 307 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 308 LabelMapTy LabelMap; 309 310 // A list of blocks that end with a "goto" that must be backpatched to their 311 // resolved targets upon completion of CFG construction. 312 typedef std::vector<JumpSource> BackpatchBlocksTy; 313 BackpatchBlocksTy BackpatchBlocks; 314 315 // A list of labels whose address has been taken (for indirect gotos). 316 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 317 LabelSetTy AddressTakenLabels; 318 319 bool badCFG; 320 const CFG::BuildOptions &BuildOpts; 321 322 // State to track for building switch statements. 323 bool switchExclusivelyCovered; 324 Expr::EvalResult *switchCond; 325 326 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 327 const Stmt *lastLookup; 328 329 // Caches boolean evaluations of expressions to avoid multiple re-evaluations 330 // during construction of branches for chained logical operators. 331 typedef llvm::DenseMap<Expr *, TryResult> CachedBoolEvalsTy; 332 CachedBoolEvalsTy CachedBoolEvals; 333 334 public: 335 explicit CFGBuilder(ASTContext *astContext, 336 const CFG::BuildOptions &buildOpts) 337 : Context(astContext), cfg(new CFG()), // crew a new CFG 338 Block(NULL), Succ(NULL), 339 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 340 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 341 switchExclusivelyCovered(false), switchCond(0), 342 cachedEntry(0), lastLookup(0) {} 343 344 // buildCFG - Used by external clients to construct the CFG. 345 CFG* buildCFG(const Decl *D, Stmt *Statement); 346 347 bool alwaysAdd(const Stmt *stmt); 348 349 private: 350 // Visitors to walk an AST and construct the CFG. 351 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 352 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 353 CFGBlock *VisitBreakStmt(BreakStmt *B); 354 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 355 CFGBlock *VisitCaseStmt(CaseStmt *C); 356 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 357 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 358 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 359 AddStmtChoice asc); 360 CFGBlock *VisitContinueStmt(ContinueStmt *C); 361 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 362 AddStmtChoice asc); 363 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 364 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 365 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 366 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 367 AddStmtChoice asc); 368 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 369 AddStmtChoice asc); 370 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 371 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 372 CFGBlock *VisitDeclStmt(DeclStmt *DS); 373 CFGBlock *VisitDeclSubExpr(DeclStmt *DS); 374 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 375 CFGBlock *VisitDoStmt(DoStmt *D); 376 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc); 377 CFGBlock *VisitForStmt(ForStmt *F); 378 CFGBlock *VisitGotoStmt(GotoStmt *G); 379 CFGBlock *VisitIfStmt(IfStmt *I); 380 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 381 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 382 CFGBlock *VisitLabelStmt(LabelStmt *L); 383 CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc); 384 CFGBlock *VisitLogicalOperator(BinaryOperator *B); 385 std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B, 386 Stmt *Term, 387 CFGBlock *TrueBlock, 388 CFGBlock *FalseBlock); 389 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 390 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 391 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 392 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 393 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 394 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S); 395 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 396 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E); 397 CFGBlock *VisitReturnStmt(ReturnStmt *R); 398 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 399 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 400 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 401 AddStmtChoice asc); 402 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 403 CFGBlock *VisitWhileStmt(WhileStmt *W); 404 405 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 406 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 407 CFGBlock *VisitChildren(Stmt *S); 408 CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc); 409 410 // Visitors to walk an AST and generate destructors of temporaries in 411 // full expression. 412 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 413 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 414 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 415 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 416 bool BindToTemporary); 417 CFGBlock * 418 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 419 bool BindToTemporary); 420 421 // NYS == Not Yet Supported 422 CFGBlock *NYS() { 423 badCFG = true; 424 return Block; 425 } 426 427 void autoCreateBlock() { if (!Block) Block = createBlock(); } 428 CFGBlock *createBlock(bool add_successor = true); 429 CFGBlock *createNoReturnBlock(); 430 431 CFGBlock *addStmt(Stmt *S) { 432 return Visit(S, AddStmtChoice::AlwaysAdd); 433 } 434 CFGBlock *addInitializer(CXXCtorInitializer *I); 435 void addAutomaticObjDtors(LocalScope::const_iterator B, 436 LocalScope::const_iterator E, Stmt *S); 437 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 438 439 // Local scopes creation. 440 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 441 442 void addLocalScopeForStmt(Stmt *S); 443 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 444 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 445 446 void addLocalScopeAndDtors(Stmt *S); 447 448 // Interface to CFGBlock - adding CFGElements. 449 void appendStmt(CFGBlock *B, const Stmt *S) { 450 if (alwaysAdd(S) && cachedEntry) 451 cachedEntry->second = B; 452 453 // All block-level expressions should have already been IgnoreParens()ed. 454 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 455 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 456 } 457 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 458 B->appendInitializer(I, cfg->getBumpVectorContext()); 459 } 460 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 461 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 462 } 463 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 464 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 465 } 466 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 467 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 468 } 469 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 470 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 471 } 472 473 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 474 LocalScope::const_iterator B, LocalScope::const_iterator E); 475 476 void addSuccessor(CFGBlock *B, CFGBlock *S) { 477 B->addSuccessor(S, cfg->getBumpVectorContext()); 478 } 479 480 /// Try and evaluate an expression to an integer constant. 481 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 482 if (!BuildOpts.PruneTriviallyFalseEdges) 483 return false; 484 return !S->isTypeDependent() && 485 !S->isValueDependent() && 486 S->EvaluateAsRValue(outResult, *Context); 487 } 488 489 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 490 /// if we can evaluate to a known value, otherwise return -1. 491 TryResult tryEvaluateBool(Expr *S) { 492 if (!BuildOpts.PruneTriviallyFalseEdges || 493 S->isTypeDependent() || S->isValueDependent()) 494 return TryResult(); 495 496 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) { 497 if (Bop->isLogicalOp()) { 498 // Check the cache first. 499 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S); 500 if (I != CachedBoolEvals.end()) 501 return I->second; // already in map; 502 503 // Retrieve result at first, or the map might be updated. 504 TryResult Result = evaluateAsBooleanConditionNoCache(S); 505 CachedBoolEvals[S] = Result; // update or insert 506 return Result; 507 } 508 else { 509 switch (Bop->getOpcode()) { 510 default: break; 511 // For 'x & 0' and 'x * 0', we can determine that 512 // the value is always false. 513 case BO_Mul: 514 case BO_And: { 515 // If either operand is zero, we know the value 516 // must be false. 517 llvm::APSInt IntVal; 518 if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) { 519 if (IntVal.getBoolValue() == false) { 520 return TryResult(false); 521 } 522 } 523 if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) { 524 if (IntVal.getBoolValue() == false) { 525 return TryResult(false); 526 } 527 } 528 } 529 break; 530 } 531 } 532 } 533 534 return evaluateAsBooleanConditionNoCache(S); 535 } 536 537 /// \brief Evaluate as boolean \param E without using the cache. 538 TryResult evaluateAsBooleanConditionNoCache(Expr *E) { 539 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) { 540 if (Bop->isLogicalOp()) { 541 TryResult LHS = tryEvaluateBool(Bop->getLHS()); 542 if (LHS.isKnown()) { 543 // We were able to evaluate the LHS, see if we can get away with not 544 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1 545 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr)) 546 return LHS.isTrue(); 547 548 TryResult RHS = tryEvaluateBool(Bop->getRHS()); 549 if (RHS.isKnown()) { 550 if (Bop->getOpcode() == BO_LOr) 551 return LHS.isTrue() || RHS.isTrue(); 552 else 553 return LHS.isTrue() && RHS.isTrue(); 554 } 555 } else { 556 TryResult RHS = tryEvaluateBool(Bop->getRHS()); 557 if (RHS.isKnown()) { 558 // We can't evaluate the LHS; however, sometimes the result 559 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 560 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr)) 561 return RHS.isTrue(); 562 } 563 } 564 565 return TryResult(); 566 } 567 } 568 569 bool Result; 570 if (E->EvaluateAsBooleanCondition(Result, *Context)) 571 return Result; 572 573 return TryResult(); 574 } 575 576 }; 577 578 inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 579 const Stmt *stmt) const { 580 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 581 } 582 583 bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 584 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 585 586 if (!BuildOpts.forcedBlkExprs) 587 return shouldAdd; 588 589 if (lastLookup == stmt) { 590 if (cachedEntry) { 591 assert(cachedEntry->first == stmt); 592 return true; 593 } 594 return shouldAdd; 595 } 596 597 lastLookup = stmt; 598 599 // Perform the lookup! 600 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 601 602 if (!fb) { 603 // No need to update 'cachedEntry', since it will always be null. 604 assert(cachedEntry == 0); 605 return shouldAdd; 606 } 607 608 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 609 if (itr == fb->end()) { 610 cachedEntry = 0; 611 return shouldAdd; 612 } 613 614 cachedEntry = &*itr; 615 return true; 616 } 617 618 // FIXME: Add support for dependent-sized array types in C++? 619 // Does it even make sense to build a CFG for an uninstantiated template? 620 static const VariableArrayType *FindVA(const Type *t) { 621 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 622 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 623 if (vat->getSizeExpr()) 624 return vat; 625 626 t = vt->getElementType().getTypePtr(); 627 } 628 629 return 0; 630 } 631 632 /// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 633 /// arbitrary statement. Examples include a single expression or a function 634 /// body (compound statement). The ownership of the returned CFG is 635 /// transferred to the caller. If CFG construction fails, this method returns 636 /// NULL. 637 CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 638 assert(cfg.get()); 639 if (!Statement) 640 return NULL; 641 642 // Create an empty block that will serve as the exit block for the CFG. Since 643 // this is the first block added to the CFG, it will be implicitly registered 644 // as the exit block. 645 Succ = createBlock(); 646 assert(Succ == &cfg->getExit()); 647 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 648 649 if (BuildOpts.AddImplicitDtors) 650 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 651 addImplicitDtorsForDestructor(DD); 652 653 // Visit the statements and create the CFG. 654 CFGBlock *B = addStmt(Statement); 655 656 if (badCFG) 657 return NULL; 658 659 // For C++ constructor add initializers to CFG. 660 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 661 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 662 E = CD->init_rend(); I != E; ++I) { 663 B = addInitializer(*I); 664 if (badCFG) 665 return NULL; 666 } 667 } 668 669 if (B) 670 Succ = B; 671 672 // Backpatch the gotos whose label -> block mappings we didn't know when we 673 // encountered them. 674 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 675 E = BackpatchBlocks.end(); I != E; ++I ) { 676 677 CFGBlock *B = I->block; 678 GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 679 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 680 681 // If there is no target for the goto, then we are looking at an 682 // incomplete AST. Handle this by not registering a successor. 683 if (LI == LabelMap.end()) continue; 684 685 JumpTarget JT = LI->second; 686 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 687 JT.scopePosition); 688 addSuccessor(B, JT.block); 689 } 690 691 // Add successors to the Indirect Goto Dispatch block (if we have one). 692 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 693 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 694 E = AddressTakenLabels.end(); I != E; ++I ) { 695 696 // Lookup the target block. 697 LabelMapTy::iterator LI = LabelMap.find(*I); 698 699 // If there is no target block that contains label, then we are looking 700 // at an incomplete AST. Handle this by not registering a successor. 701 if (LI == LabelMap.end()) continue; 702 703 addSuccessor(B, LI->second.block); 704 } 705 706 // Create an empty entry block that has no predecessors. 707 cfg->setEntry(createBlock()); 708 709 return cfg.take(); 710 } 711 712 /// createBlock - Used to lazily create blocks that are connected 713 /// to the current (global) succcessor. 714 CFGBlock *CFGBuilder::createBlock(bool add_successor) { 715 CFGBlock *B = cfg->createBlock(); 716 if (add_successor && Succ) 717 addSuccessor(B, Succ); 718 return B; 719 } 720 721 /// createNoReturnBlock - Used to create a block is a 'noreturn' point in the 722 /// CFG. It is *not* connected to the current (global) successor, and instead 723 /// directly tied to the exit block in order to be reachable. 724 CFGBlock *CFGBuilder::createNoReturnBlock() { 725 CFGBlock *B = createBlock(false); 726 B->setHasNoReturnElement(); 727 addSuccessor(B, &cfg->getExit()); 728 return B; 729 } 730 731 /// addInitializer - Add C++ base or member initializer element to CFG. 732 CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 733 if (!BuildOpts.AddInitializers) 734 return Block; 735 736 bool IsReference = false; 737 bool HasTemporaries = false; 738 739 // Destructors of temporaries in initialization expression should be called 740 // after initialization finishes. 741 Expr *Init = I->getInit(); 742 if (Init) { 743 if (FieldDecl *FD = I->getAnyMember()) 744 IsReference = FD->getType()->isReferenceType(); 745 HasTemporaries = isa<ExprWithCleanups>(Init); 746 747 if (BuildOpts.AddTemporaryDtors && HasTemporaries) { 748 // Generate destructors for temporaries in initialization expression. 749 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 750 IsReference); 751 } 752 } 753 754 autoCreateBlock(); 755 appendInitializer(Block, I); 756 757 if (Init) { 758 if (HasTemporaries) { 759 // For expression with temporaries go directly to subexpression to omit 760 // generating destructors for the second time. 761 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 762 } 763 return Visit(Init); 764 } 765 766 return Block; 767 } 768 769 /// \brief Retrieve the type of the temporary object whose lifetime was 770 /// extended by a local reference with the given initializer. 771 static QualType getReferenceInitTemporaryType(ASTContext &Context, 772 const Expr *Init) { 773 while (true) { 774 // Skip parentheses. 775 Init = Init->IgnoreParens(); 776 777 // Skip through cleanups. 778 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) { 779 Init = EWC->getSubExpr(); 780 continue; 781 } 782 783 // Skip through the temporary-materialization expression. 784 if (const MaterializeTemporaryExpr *MTE 785 = dyn_cast<MaterializeTemporaryExpr>(Init)) { 786 Init = MTE->GetTemporaryExpr(); 787 continue; 788 } 789 790 // Skip derived-to-base and no-op casts. 791 if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) { 792 if ((CE->getCastKind() == CK_DerivedToBase || 793 CE->getCastKind() == CK_UncheckedDerivedToBase || 794 CE->getCastKind() == CK_NoOp) && 795 Init->getType()->isRecordType()) { 796 Init = CE->getSubExpr(); 797 continue; 798 } 799 } 800 801 // Skip member accesses into rvalues. 802 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) { 803 if (!ME->isArrow() && ME->getBase()->isRValue()) { 804 Init = ME->getBase(); 805 continue; 806 } 807 } 808 809 break; 810 } 811 812 return Init->getType(); 813 } 814 815 /// addAutomaticObjDtors - Add to current block automatic objects destructors 816 /// for objects in range of local scope positions. Use S as trigger statement 817 /// for destructors. 818 void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 819 LocalScope::const_iterator E, Stmt *S) { 820 if (!BuildOpts.AddImplicitDtors) 821 return; 822 823 if (B == E) 824 return; 825 826 // We need to append the destructors in reverse order, but any one of them 827 // may be a no-return destructor which changes the CFG. As a result, buffer 828 // this sequence up and replay them in reverse order when appending onto the 829 // CFGBlock(s). 830 SmallVector<VarDecl*, 10> Decls; 831 Decls.reserve(B.distance(E)); 832 for (LocalScope::const_iterator I = B; I != E; ++I) 833 Decls.push_back(*I); 834 835 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 836 E = Decls.rend(); 837 I != E; ++I) { 838 // If this destructor is marked as a no-return destructor, we need to 839 // create a new block for the destructor which does not have as a successor 840 // anything built thus far: control won't flow out of this block. 841 QualType Ty = (*I)->getType(); 842 if (Ty->isReferenceType()) { 843 Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit()); 844 } 845 Ty = Context->getBaseElementType(Ty); 846 847 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 848 if (Dtor->isNoReturn()) 849 Block = createNoReturnBlock(); 850 else 851 autoCreateBlock(); 852 853 appendAutomaticObjDtor(Block, *I, S); 854 } 855 } 856 857 /// addImplicitDtorsForDestructor - Add implicit destructors generated for 858 /// base and member objects in destructor. 859 void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 860 assert (BuildOpts.AddImplicitDtors 861 && "Can be called only when dtors should be added"); 862 const CXXRecordDecl *RD = DD->getParent(); 863 864 // At the end destroy virtual base objects. 865 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 866 VE = RD->vbases_end(); VI != VE; ++VI) { 867 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 868 if (!CD->hasTrivialDestructor()) { 869 autoCreateBlock(); 870 appendBaseDtor(Block, VI); 871 } 872 } 873 874 // Before virtual bases destroy direct base objects. 875 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 876 BE = RD->bases_end(); BI != BE; ++BI) { 877 if (!BI->isVirtual()) { 878 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 879 if (!CD->hasTrivialDestructor()) { 880 autoCreateBlock(); 881 appendBaseDtor(Block, BI); 882 } 883 } 884 } 885 886 // First destroy member objects. 887 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 888 FE = RD->field_end(); FI != FE; ++FI) { 889 // Check for constant size array. Set type to array element type. 890 QualType QT = FI->getType(); 891 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 892 if (AT->getSize() == 0) 893 continue; 894 QT = AT->getElementType(); 895 } 896 897 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 898 if (!CD->hasTrivialDestructor()) { 899 autoCreateBlock(); 900 appendMemberDtor(Block, *FI); 901 } 902 } 903 } 904 905 /// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 906 /// way return valid LocalScope object. 907 LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 908 if (!Scope) { 909 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 910 Scope = alloc.Allocate<LocalScope>(); 911 BumpVectorContext ctx(alloc); 912 new (Scope) LocalScope(ctx, ScopePos); 913 } 914 return Scope; 915 } 916 917 /// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 918 /// that should create implicit scope (e.g. if/else substatements). 919 void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 920 if (!BuildOpts.AddImplicitDtors) 921 return; 922 923 LocalScope *Scope = 0; 924 925 // For compound statement we will be creating explicit scope. 926 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 927 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 928 ; BI != BE; ++BI) { 929 Stmt *SI = (*BI)->stripLabelLikeStatements(); 930 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 931 Scope = addLocalScopeForDeclStmt(DS, Scope); 932 } 933 return; 934 } 935 936 // For any other statement scope will be implicit and as such will be 937 // interesting only for DeclStmt. 938 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 939 addLocalScopeForDeclStmt(DS); 940 } 941 942 /// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 943 /// reuse Scope if not NULL. 944 LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 945 LocalScope* Scope) { 946 if (!BuildOpts.AddImplicitDtors) 947 return Scope; 948 949 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 950 ; DI != DE; ++DI) { 951 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 952 Scope = addLocalScopeForVarDecl(VD, Scope); 953 } 954 return Scope; 955 } 956 957 /// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 958 /// create add scope for automatic objects and temporary objects bound to 959 /// const reference. Will reuse Scope if not NULL. 960 LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 961 LocalScope* Scope) { 962 if (!BuildOpts.AddImplicitDtors) 963 return Scope; 964 965 // Check if variable is local. 966 switch (VD->getStorageClass()) { 967 case SC_None: 968 case SC_Auto: 969 case SC_Register: 970 break; 971 default: return Scope; 972 } 973 974 // Check for const references bound to temporary. Set type to pointee. 975 QualType QT = VD->getType(); 976 if (QT.getTypePtr()->isReferenceType()) { 977 if (!VD->extendsLifetimeOfTemporary()) 978 return Scope; 979 980 QT = getReferenceInitTemporaryType(*Context, VD->getInit()); 981 } 982 983 // Check for constant size array. Set type to array element type. 984 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 985 if (AT->getSize() == 0) 986 return Scope; 987 QT = AT->getElementType(); 988 } 989 990 // Check if type is a C++ class with non-trivial destructor. 991 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 992 if (!CD->hasTrivialDestructor()) { 993 // Add the variable to scope 994 Scope = createOrReuseLocalScope(Scope); 995 Scope->addVar(VD); 996 ScopePos = Scope->begin(); 997 } 998 return Scope; 999 } 1000 1001 /// addLocalScopeAndDtors - For given statement add local scope for it and 1002 /// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 1003 void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 1004 if (!BuildOpts.AddImplicitDtors) 1005 return; 1006 1007 LocalScope::const_iterator scopeBeginPos = ScopePos; 1008 addLocalScopeForStmt(S); 1009 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 1010 } 1011 1012 /// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 1013 /// variables with automatic storage duration to CFGBlock's elements vector. 1014 /// Elements will be prepended to physical beginning of the vector which 1015 /// happens to be logical end. Use blocks terminator as statement that specifies 1016 /// destructors call site. 1017 /// FIXME: This mechanism for adding automatic destructors doesn't handle 1018 /// no-return destructors properly. 1019 void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 1020 LocalScope::const_iterator B, LocalScope::const_iterator E) { 1021 BumpVectorContext &C = cfg->getBumpVectorContext(); 1022 CFGBlock::iterator InsertPos 1023 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 1024 for (LocalScope::const_iterator I = B; I != E; ++I) 1025 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 1026 Blk->getTerminator()); 1027 } 1028 1029 /// Visit - Walk the subtree of a statement and add extra 1030 /// blocks for ternary operators, &&, and ||. We also process "," and 1031 /// DeclStmts (which may contain nested control-flow). 1032 CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 1033 if (!S) { 1034 badCFG = true; 1035 return 0; 1036 } 1037 1038 if (Expr *E = dyn_cast<Expr>(S)) 1039 S = E->IgnoreParens(); 1040 1041 switch (S->getStmtClass()) { 1042 default: 1043 return VisitStmt(S, asc); 1044 1045 case Stmt::AddrLabelExprClass: 1046 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 1047 1048 case Stmt::BinaryConditionalOperatorClass: 1049 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 1050 1051 case Stmt::BinaryOperatorClass: 1052 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 1053 1054 case Stmt::BlockExprClass: 1055 return VisitNoRecurse(cast<Expr>(S), asc); 1056 1057 case Stmt::BreakStmtClass: 1058 return VisitBreakStmt(cast<BreakStmt>(S)); 1059 1060 case Stmt::CallExprClass: 1061 case Stmt::CXXOperatorCallExprClass: 1062 case Stmt::CXXMemberCallExprClass: 1063 case Stmt::UserDefinedLiteralClass: 1064 return VisitCallExpr(cast<CallExpr>(S), asc); 1065 1066 case Stmt::CaseStmtClass: 1067 return VisitCaseStmt(cast<CaseStmt>(S)); 1068 1069 case Stmt::ChooseExprClass: 1070 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 1071 1072 case Stmt::CompoundStmtClass: 1073 return VisitCompoundStmt(cast<CompoundStmt>(S)); 1074 1075 case Stmt::ConditionalOperatorClass: 1076 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 1077 1078 case Stmt::ContinueStmtClass: 1079 return VisitContinueStmt(cast<ContinueStmt>(S)); 1080 1081 case Stmt::CXXCatchStmtClass: 1082 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 1083 1084 case Stmt::ExprWithCleanupsClass: 1085 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 1086 1087 case Stmt::CXXDefaultArgExprClass: 1088 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the 1089 // called function's declaration, not by the caller. If we simply add 1090 // this expression to the CFG, we could end up with the same Expr 1091 // appearing multiple times. 1092 // PR13385 / <rdar://problem/12156507> 1093 return VisitStmt(S, asc); 1094 1095 case Stmt::CXXBindTemporaryExprClass: 1096 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 1097 1098 case Stmt::CXXConstructExprClass: 1099 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 1100 1101 case Stmt::CXXFunctionalCastExprClass: 1102 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 1103 1104 case Stmt::CXXTemporaryObjectExprClass: 1105 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 1106 1107 case Stmt::CXXThrowExprClass: 1108 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 1109 1110 case Stmt::CXXTryStmtClass: 1111 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 1112 1113 case Stmt::CXXForRangeStmtClass: 1114 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 1115 1116 case Stmt::DeclStmtClass: 1117 return VisitDeclStmt(cast<DeclStmt>(S)); 1118 1119 case Stmt::DefaultStmtClass: 1120 return VisitDefaultStmt(cast<DefaultStmt>(S)); 1121 1122 case Stmt::DoStmtClass: 1123 return VisitDoStmt(cast<DoStmt>(S)); 1124 1125 case Stmt::ForStmtClass: 1126 return VisitForStmt(cast<ForStmt>(S)); 1127 1128 case Stmt::GotoStmtClass: 1129 return VisitGotoStmt(cast<GotoStmt>(S)); 1130 1131 case Stmt::IfStmtClass: 1132 return VisitIfStmt(cast<IfStmt>(S)); 1133 1134 case Stmt::ImplicitCastExprClass: 1135 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 1136 1137 case Stmt::IndirectGotoStmtClass: 1138 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 1139 1140 case Stmt::LabelStmtClass: 1141 return VisitLabelStmt(cast<LabelStmt>(S)); 1142 1143 case Stmt::LambdaExprClass: 1144 return VisitLambdaExpr(cast<LambdaExpr>(S), asc); 1145 1146 case Stmt::MemberExprClass: 1147 return VisitMemberExpr(cast<MemberExpr>(S), asc); 1148 1149 case Stmt::NullStmtClass: 1150 return Block; 1151 1152 case Stmt::ObjCAtCatchStmtClass: 1153 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 1154 1155 case Stmt::ObjCAutoreleasePoolStmtClass: 1156 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S)); 1157 1158 case Stmt::ObjCAtSynchronizedStmtClass: 1159 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 1160 1161 case Stmt::ObjCAtThrowStmtClass: 1162 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 1163 1164 case Stmt::ObjCAtTryStmtClass: 1165 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 1166 1167 case Stmt::ObjCForCollectionStmtClass: 1168 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 1169 1170 case Stmt::OpaqueValueExprClass: 1171 return Block; 1172 1173 case Stmt::PseudoObjectExprClass: 1174 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S)); 1175 1176 case Stmt::ReturnStmtClass: 1177 return VisitReturnStmt(cast<ReturnStmt>(S)); 1178 1179 case Stmt::UnaryExprOrTypeTraitExprClass: 1180 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 1181 asc); 1182 1183 case Stmt::StmtExprClass: 1184 return VisitStmtExpr(cast<StmtExpr>(S), asc); 1185 1186 case Stmt::SwitchStmtClass: 1187 return VisitSwitchStmt(cast<SwitchStmt>(S)); 1188 1189 case Stmt::UnaryOperatorClass: 1190 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 1191 1192 case Stmt::WhileStmtClass: 1193 return VisitWhileStmt(cast<WhileStmt>(S)); 1194 } 1195 } 1196 1197 CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1198 if (asc.alwaysAdd(*this, S)) { 1199 autoCreateBlock(); 1200 appendStmt(Block, S); 1201 } 1202 1203 return VisitChildren(S); 1204 } 1205 1206 /// VisitChildren - Visit the children of a Stmt. 1207 CFGBlock *CFGBuilder::VisitChildren(Stmt *S) { 1208 CFGBlock *B = Block; 1209 1210 // Visit the children in their reverse order so that they appear in 1211 // left-to-right (natural) order in the CFG. 1212 reverse_children RChildren(S); 1213 for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end(); 1214 I != E; ++I) { 1215 if (Stmt *Child = *I) 1216 if (CFGBlock *R = Visit(Child)) 1217 B = R; 1218 } 1219 return B; 1220 } 1221 1222 CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1223 AddStmtChoice asc) { 1224 AddressTakenLabels.insert(A->getLabel()); 1225 1226 if (asc.alwaysAdd(*this, A)) { 1227 autoCreateBlock(); 1228 appendStmt(Block, A); 1229 } 1230 1231 return Block; 1232 } 1233 1234 CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1235 AddStmtChoice asc) { 1236 if (asc.alwaysAdd(*this, U)) { 1237 autoCreateBlock(); 1238 appendStmt(Block, U); 1239 } 1240 1241 return Visit(U->getSubExpr(), AddStmtChoice()); 1242 } 1243 1244 CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) { 1245 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1246 appendStmt(ConfluenceBlock, B); 1247 1248 if (badCFG) 1249 return 0; 1250 1251 return VisitLogicalOperator(B, 0, ConfluenceBlock, ConfluenceBlock).first; 1252 } 1253 1254 std::pair<CFGBlock*, CFGBlock*> 1255 CFGBuilder::VisitLogicalOperator(BinaryOperator *B, 1256 Stmt *Term, 1257 CFGBlock *TrueBlock, 1258 CFGBlock *FalseBlock) { 1259 1260 // Introspect the RHS. If it is a nested logical operation, we recursively 1261 // build the CFG using this function. Otherwise, resort to default 1262 // CFG construction behavior. 1263 Expr *RHS = B->getRHS()->IgnoreParens(); 1264 CFGBlock *RHSBlock, *ExitBlock; 1265 1266 do { 1267 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS)) 1268 if (B_RHS->isLogicalOp()) { 1269 llvm::tie(RHSBlock, ExitBlock) = 1270 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock); 1271 break; 1272 } 1273 1274 // The RHS is not a nested logical operation. Don't push the terminator 1275 // down further, but instead visit RHS and construct the respective 1276 // pieces of the CFG, and link up the RHSBlock with the terminator 1277 // we have been provided. 1278 ExitBlock = RHSBlock = createBlock(false); 1279 1280 if (!Term) { 1281 assert(TrueBlock == FalseBlock); 1282 addSuccessor(RHSBlock, TrueBlock); 1283 } 1284 else { 1285 RHSBlock->setTerminator(Term); 1286 TryResult KnownVal = tryEvaluateBool(RHS); 1287 addSuccessor(RHSBlock, KnownVal.isFalse() ? NULL : TrueBlock); 1288 addSuccessor(RHSBlock, KnownVal.isTrue() ? NULL : FalseBlock); 1289 } 1290 1291 Block = RHSBlock; 1292 RHSBlock = addStmt(RHS); 1293 } 1294 while (false); 1295 1296 if (badCFG) 1297 return std::make_pair((CFGBlock*)0, (CFGBlock*)0); 1298 1299 // Generate the blocks for evaluating the LHS. 1300 Expr *LHS = B->getLHS()->IgnoreParens(); 1301 1302 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS)) 1303 if (B_LHS->isLogicalOp()) { 1304 if (B->getOpcode() == BO_LOr) 1305 FalseBlock = RHSBlock; 1306 else 1307 TrueBlock = RHSBlock; 1308 1309 // For the LHS, treat 'B' as the terminator that we want to sink 1310 // into the nested branch. The RHS always gets the top-most 1311 // terminator. 1312 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock); 1313 } 1314 1315 // Create the block evaluating the LHS. 1316 // This contains the '&&' or '||' as the terminator. 1317 CFGBlock *LHSBlock = createBlock(false); 1318 LHSBlock->setTerminator(B); 1319 1320 Block = LHSBlock; 1321 CFGBlock *EntryLHSBlock = addStmt(LHS); 1322 1323 if (badCFG) 1324 return std::make_pair((CFGBlock*)0, (CFGBlock*)0); 1325 1326 // See if this is a known constant. 1327 TryResult KnownVal = tryEvaluateBool(LHS); 1328 1329 // Now link the LHSBlock with RHSBlock. 1330 if (B->getOpcode() == BO_LOr) { 1331 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : TrueBlock); 1332 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : RHSBlock); 1333 } else { 1334 assert(B->getOpcode() == BO_LAnd); 1335 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1336 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : FalseBlock); 1337 } 1338 1339 return std::make_pair(EntryLHSBlock, ExitBlock); 1340 } 1341 1342 1343 CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1344 AddStmtChoice asc) { 1345 // && or || 1346 if (B->isLogicalOp()) 1347 return VisitLogicalOperator(B); 1348 1349 if (B->getOpcode() == BO_Comma) { // , 1350 autoCreateBlock(); 1351 appendStmt(Block, B); 1352 addStmt(B->getRHS()); 1353 return addStmt(B->getLHS()); 1354 } 1355 1356 if (B->isAssignmentOp()) { 1357 if (asc.alwaysAdd(*this, B)) { 1358 autoCreateBlock(); 1359 appendStmt(Block, B); 1360 } 1361 Visit(B->getLHS()); 1362 return Visit(B->getRHS()); 1363 } 1364 1365 if (asc.alwaysAdd(*this, B)) { 1366 autoCreateBlock(); 1367 appendStmt(Block, B); 1368 } 1369 1370 CFGBlock *RBlock = Visit(B->getRHS()); 1371 CFGBlock *LBlock = Visit(B->getLHS()); 1372 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1373 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1374 // return RBlock. Otherwise we'll incorrectly return NULL. 1375 return (LBlock ? LBlock : RBlock); 1376 } 1377 1378 CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) { 1379 if (asc.alwaysAdd(*this, E)) { 1380 autoCreateBlock(); 1381 appendStmt(Block, E); 1382 } 1383 return Block; 1384 } 1385 1386 CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1387 // "break" is a control-flow statement. Thus we stop processing the current 1388 // block. 1389 if (badCFG) 1390 return 0; 1391 1392 // Now create a new block that ends with the break statement. 1393 Block = createBlock(false); 1394 Block->setTerminator(B); 1395 1396 // If there is no target for the break, then we are looking at an incomplete 1397 // AST. This means that the CFG cannot be constructed. 1398 if (BreakJumpTarget.block) { 1399 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1400 addSuccessor(Block, BreakJumpTarget.block); 1401 } else 1402 badCFG = true; 1403 1404 1405 return Block; 1406 } 1407 1408 static bool CanThrow(Expr *E, ASTContext &Ctx) { 1409 QualType Ty = E->getType(); 1410 if (Ty->isFunctionPointerType()) 1411 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1412 else if (Ty->isBlockPointerType()) 1413 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1414 1415 const FunctionType *FT = Ty->getAs<FunctionType>(); 1416 if (FT) { 1417 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1418 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) && 1419 Proto->isNothrow(Ctx)) 1420 return false; 1421 } 1422 return true; 1423 } 1424 1425 CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1426 // Compute the callee type. 1427 QualType calleeType = C->getCallee()->getType(); 1428 if (calleeType == Context->BoundMemberTy) { 1429 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1430 1431 // We should only get a null bound type if processing a dependent 1432 // CFG. Recover by assuming nothing. 1433 if (!boundType.isNull()) calleeType = boundType; 1434 } 1435 1436 // If this is a call to a no-return function, this stops the block here. 1437 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1438 1439 bool AddEHEdge = false; 1440 1441 // Languages without exceptions are assumed to not throw. 1442 if (Context->getLangOpts().Exceptions) { 1443 if (BuildOpts.AddEHEdges) 1444 AddEHEdge = true; 1445 } 1446 1447 if (FunctionDecl *FD = C->getDirectCallee()) { 1448 if (FD->isNoReturn()) 1449 NoReturn = true; 1450 if (FD->hasAttr<NoThrowAttr>()) 1451 AddEHEdge = false; 1452 } 1453 1454 if (!CanThrow(C->getCallee(), *Context)) 1455 AddEHEdge = false; 1456 1457 if (!NoReturn && !AddEHEdge) 1458 return VisitStmt(C, asc.withAlwaysAdd(true)); 1459 1460 if (Block) { 1461 Succ = Block; 1462 if (badCFG) 1463 return 0; 1464 } 1465 1466 if (NoReturn) 1467 Block = createNoReturnBlock(); 1468 else 1469 Block = createBlock(); 1470 1471 appendStmt(Block, C); 1472 1473 if (AddEHEdge) { 1474 // Add exceptional edges. 1475 if (TryTerminatedBlock) 1476 addSuccessor(Block, TryTerminatedBlock); 1477 else 1478 addSuccessor(Block, &cfg->getExit()); 1479 } 1480 1481 return VisitChildren(C); 1482 } 1483 1484 CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1485 AddStmtChoice asc) { 1486 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1487 appendStmt(ConfluenceBlock, C); 1488 if (badCFG) 1489 return 0; 1490 1491 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1492 Succ = ConfluenceBlock; 1493 Block = NULL; 1494 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1495 if (badCFG) 1496 return 0; 1497 1498 Succ = ConfluenceBlock; 1499 Block = NULL; 1500 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1501 if (badCFG) 1502 return 0; 1503 1504 Block = createBlock(false); 1505 // See if this is a known constant. 1506 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1507 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1508 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1509 Block->setTerminator(C); 1510 return addStmt(C->getCond()); 1511 } 1512 1513 1514 CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1515 addLocalScopeAndDtors(C); 1516 CFGBlock *LastBlock = Block; 1517 1518 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1519 I != E; ++I ) { 1520 // If we hit a segment of code just containing ';' (NullStmts), we can 1521 // get a null block back. In such cases, just use the LastBlock 1522 if (CFGBlock *newBlock = addStmt(*I)) 1523 LastBlock = newBlock; 1524 1525 if (badCFG) 1526 return NULL; 1527 } 1528 1529 return LastBlock; 1530 } 1531 1532 CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1533 AddStmtChoice asc) { 1534 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1535 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1536 1537 // Create the confluence block that will "merge" the results of the ternary 1538 // expression. 1539 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1540 appendStmt(ConfluenceBlock, C); 1541 if (badCFG) 1542 return 0; 1543 1544 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1545 1546 // Create a block for the LHS expression if there is an LHS expression. A 1547 // GCC extension allows LHS to be NULL, causing the condition to be the 1548 // value that is returned instead. 1549 // e.g: x ?: y is shorthand for: x ? x : y; 1550 Succ = ConfluenceBlock; 1551 Block = NULL; 1552 CFGBlock *LHSBlock = 0; 1553 const Expr *trueExpr = C->getTrueExpr(); 1554 if (trueExpr != opaqueValue) { 1555 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1556 if (badCFG) 1557 return 0; 1558 Block = NULL; 1559 } 1560 else 1561 LHSBlock = ConfluenceBlock; 1562 1563 // Create the block for the RHS expression. 1564 Succ = ConfluenceBlock; 1565 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1566 if (badCFG) 1567 return 0; 1568 1569 // If the condition is a logical '&&' or '||', build a more accurate CFG. 1570 if (BinaryOperator *Cond = 1571 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens())) 1572 if (Cond->isLogicalOp()) 1573 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first; 1574 1575 // Create the block that will contain the condition. 1576 Block = createBlock(false); 1577 1578 // See if this is a known constant. 1579 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1580 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1581 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1582 Block->setTerminator(C); 1583 Expr *condExpr = C->getCond(); 1584 1585 if (opaqueValue) { 1586 // Run the condition expression if it's not trivially expressed in 1587 // terms of the opaque value (or if there is no opaque value). 1588 if (condExpr != opaqueValue) 1589 addStmt(condExpr); 1590 1591 // Before that, run the common subexpression if there was one. 1592 // At least one of this or the above will be run. 1593 return addStmt(BCO->getCommon()); 1594 } 1595 1596 return addStmt(condExpr); 1597 } 1598 1599 CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1600 // Check if the Decl is for an __label__. If so, elide it from the 1601 // CFG entirely. 1602 if (isa<LabelDecl>(*DS->decl_begin())) 1603 return Block; 1604 1605 // This case also handles static_asserts. 1606 if (DS->isSingleDecl()) 1607 return VisitDeclSubExpr(DS); 1608 1609 CFGBlock *B = 0; 1610 1611 // Build an individual DeclStmt for each decl. 1612 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(), 1613 E = DS->decl_rend(); 1614 I != E; ++I) { 1615 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1616 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1617 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1618 1619 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1620 // automatically freed with the CFG. 1621 DeclGroupRef DG(*I); 1622 Decl *D = *I; 1623 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1624 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1625 1626 // Append the fake DeclStmt to block. 1627 B = VisitDeclSubExpr(DSNew); 1628 } 1629 1630 return B; 1631 } 1632 1633 /// VisitDeclSubExpr - Utility method to add block-level expressions for 1634 /// DeclStmts and initializers in them. 1635 CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1636 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1637 Decl *D = DS->getSingleDecl(); 1638 1639 if (isa<StaticAssertDecl>(D)) { 1640 // static_asserts aren't added to the CFG because they do not impact 1641 // runtime semantics. 1642 return Block; 1643 } 1644 1645 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1646 1647 if (!VD) { 1648 autoCreateBlock(); 1649 appendStmt(Block, DS); 1650 return Block; 1651 } 1652 1653 bool IsReference = false; 1654 bool HasTemporaries = false; 1655 1656 // Destructors of temporaries in initialization expression should be called 1657 // after initialization finishes. 1658 Expr *Init = VD->getInit(); 1659 if (Init) { 1660 IsReference = VD->getType()->isReferenceType(); 1661 HasTemporaries = isa<ExprWithCleanups>(Init); 1662 1663 if (BuildOpts.AddTemporaryDtors && HasTemporaries) { 1664 // Generate destructors for temporaries in initialization expression. 1665 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1666 IsReference); 1667 } 1668 } 1669 1670 autoCreateBlock(); 1671 appendStmt(Block, DS); 1672 1673 // Keep track of the last non-null block, as 'Block' can be nulled out 1674 // if the initializer expression is something like a 'while' in a 1675 // statement-expression. 1676 CFGBlock *LastBlock = Block; 1677 1678 if (Init) { 1679 if (HasTemporaries) { 1680 // For expression with temporaries go directly to subexpression to omit 1681 // generating destructors for the second time. 1682 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init); 1683 if (CFGBlock *newBlock = Visit(EC->getSubExpr())) 1684 LastBlock = newBlock; 1685 } 1686 else { 1687 if (CFGBlock *newBlock = Visit(Init)) 1688 LastBlock = newBlock; 1689 } 1690 } 1691 1692 // If the type of VD is a VLA, then we must process its size expressions. 1693 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1694 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) { 1695 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr())) 1696 LastBlock = newBlock; 1697 } 1698 1699 // Remove variable from local scope. 1700 if (ScopePos && VD == *ScopePos) 1701 ++ScopePos; 1702 1703 return Block ? Block : LastBlock; 1704 } 1705 1706 CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1707 // We may see an if statement in the middle of a basic block, or it may be the 1708 // first statement we are processing. In either case, we create a new basic 1709 // block. First, we create the blocks for the then...else statements, and 1710 // then we create the block containing the if statement. If we were in the 1711 // middle of a block, we stop processing that block. That block is then the 1712 // implicit successor for the "then" and "else" clauses. 1713 1714 // Save local scope position because in case of condition variable ScopePos 1715 // won't be restored when traversing AST. 1716 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1717 1718 // Create local scope for possible condition variable. 1719 // Store scope position. Add implicit destructor. 1720 if (VarDecl *VD = I->getConditionVariable()) { 1721 LocalScope::const_iterator BeginScopePos = ScopePos; 1722 addLocalScopeForVarDecl(VD); 1723 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1724 } 1725 1726 // The block we were processing is now finished. Make it the successor 1727 // block. 1728 if (Block) { 1729 Succ = Block; 1730 if (badCFG) 1731 return 0; 1732 } 1733 1734 // Process the false branch. 1735 CFGBlock *ElseBlock = Succ; 1736 1737 if (Stmt *Else = I->getElse()) { 1738 SaveAndRestore<CFGBlock*> sv(Succ); 1739 1740 // NULL out Block so that the recursive call to Visit will 1741 // create a new basic block. 1742 Block = NULL; 1743 1744 // If branch is not a compound statement create implicit scope 1745 // and add destructors. 1746 if (!isa<CompoundStmt>(Else)) 1747 addLocalScopeAndDtors(Else); 1748 1749 ElseBlock = addStmt(Else); 1750 1751 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1752 ElseBlock = sv.get(); 1753 else if (Block) { 1754 if (badCFG) 1755 return 0; 1756 } 1757 } 1758 1759 // Process the true branch. 1760 CFGBlock *ThenBlock; 1761 { 1762 Stmt *Then = I->getThen(); 1763 assert(Then); 1764 SaveAndRestore<CFGBlock*> sv(Succ); 1765 Block = NULL; 1766 1767 // If branch is not a compound statement create implicit scope 1768 // and add destructors. 1769 if (!isa<CompoundStmt>(Then)) 1770 addLocalScopeAndDtors(Then); 1771 1772 ThenBlock = addStmt(Then); 1773 1774 if (!ThenBlock) { 1775 // We can reach here if the "then" body has all NullStmts. 1776 // Create an empty block so we can distinguish between true and false 1777 // branches in path-sensitive analyses. 1778 ThenBlock = createBlock(false); 1779 addSuccessor(ThenBlock, sv.get()); 1780 } else if (Block) { 1781 if (badCFG) 1782 return 0; 1783 } 1784 } 1785 1786 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by 1787 // having these handle the actual control-flow jump. Note that 1788 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)" 1789 // we resort to the old control-flow behavior. This special handling 1790 // removes infeasible paths from the control-flow graph by having the 1791 // control-flow transfer of '&&' or '||' go directly into the then/else 1792 // blocks directly. 1793 if (!I->getConditionVariable()) 1794 if (BinaryOperator *Cond = 1795 dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens())) 1796 if (Cond->isLogicalOp()) 1797 return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first; 1798 1799 // Now create a new block containing the if statement. 1800 Block = createBlock(false); 1801 1802 // Set the terminator of the new block to the If statement. 1803 Block->setTerminator(I); 1804 1805 // See if this is a known constant. 1806 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1807 1808 // Now add the successors. 1809 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1810 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1811 1812 // Add the condition as the last statement in the new block. This may create 1813 // new blocks as the condition may contain control-flow. Any newly created 1814 // blocks will be pointed to be "Block". 1815 CFGBlock *LastBlock = addStmt(I->getCond()); 1816 1817 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1818 // and the condition variable initialization to the CFG. 1819 if (VarDecl *VD = I->getConditionVariable()) { 1820 if (Expr *Init = VD->getInit()) { 1821 autoCreateBlock(); 1822 appendStmt(Block, I->getConditionVariableDeclStmt()); 1823 LastBlock = addStmt(Init); 1824 } 1825 } 1826 1827 return LastBlock; 1828 } 1829 1830 1831 CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1832 // If we were in the middle of a block we stop processing that block. 1833 // 1834 // NOTE: If a "return" appears in the middle of a block, this means that the 1835 // code afterwards is DEAD (unreachable). We still keep a basic block 1836 // for that code; a simple "mark-and-sweep" from the entry block will be 1837 // able to report such dead blocks. 1838 1839 // Create the new block. 1840 Block = createBlock(false); 1841 1842 // The Exit block is the only successor. 1843 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1844 addSuccessor(Block, &cfg->getExit()); 1845 1846 // Add the return statement to the block. This may create new blocks if R 1847 // contains control-flow (short-circuit operations). 1848 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1849 } 1850 1851 CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1852 // Get the block of the labeled statement. Add it to our map. 1853 addStmt(L->getSubStmt()); 1854 CFGBlock *LabelBlock = Block; 1855 1856 if (!LabelBlock) // This can happen when the body is empty, i.e. 1857 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1858 1859 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1860 "label already in map"); 1861 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1862 1863 // Labels partition blocks, so this is the end of the basic block we were 1864 // processing (L is the block's label). Because this is label (and we have 1865 // already processed the substatement) there is no extra control-flow to worry 1866 // about. 1867 LabelBlock->setLabel(L); 1868 if (badCFG) 1869 return 0; 1870 1871 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1872 Block = NULL; 1873 1874 // This block is now the implicit successor of other blocks. 1875 Succ = LabelBlock; 1876 1877 return LabelBlock; 1878 } 1879 1880 CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) { 1881 CFGBlock *LastBlock = VisitNoRecurse(E, asc); 1882 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(), 1883 et = E->capture_init_end(); it != et; ++it) { 1884 if (Expr *Init = *it) { 1885 CFGBlock *Tmp = Visit(Init); 1886 if (Tmp != 0) 1887 LastBlock = Tmp; 1888 } 1889 } 1890 return LastBlock; 1891 } 1892 1893 CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1894 // Goto is a control-flow statement. Thus we stop processing the current 1895 // block and create a new one. 1896 1897 Block = createBlock(false); 1898 Block->setTerminator(G); 1899 1900 // If we already know the mapping to the label block add the successor now. 1901 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1902 1903 if (I == LabelMap.end()) 1904 // We will need to backpatch this block later. 1905 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1906 else { 1907 JumpTarget JT = I->second; 1908 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1909 addSuccessor(Block, JT.block); 1910 } 1911 1912 return Block; 1913 } 1914 1915 CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1916 CFGBlock *LoopSuccessor = NULL; 1917 1918 // Save local scope position because in case of condition variable ScopePos 1919 // won't be restored when traversing AST. 1920 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1921 1922 // Create local scope for init statement and possible condition variable. 1923 // Add destructor for init statement and condition variable. 1924 // Store scope position for continue statement. 1925 if (Stmt *Init = F->getInit()) 1926 addLocalScopeForStmt(Init); 1927 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1928 1929 if (VarDecl *VD = F->getConditionVariable()) 1930 addLocalScopeForVarDecl(VD); 1931 LocalScope::const_iterator ContinueScopePos = ScopePos; 1932 1933 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1934 1935 // "for" is a control-flow statement. Thus we stop processing the current 1936 // block. 1937 if (Block) { 1938 if (badCFG) 1939 return 0; 1940 LoopSuccessor = Block; 1941 } else 1942 LoopSuccessor = Succ; 1943 1944 // Save the current value for the break targets. 1945 // All breaks should go to the code following the loop. 1946 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1947 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1948 1949 CFGBlock *BodyBlock = 0, *TransitionBlock = 0; 1950 1951 // Now create the loop body. 1952 { 1953 assert(F->getBody()); 1954 1955 // Save the current values for Block, Succ, continue and break targets. 1956 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1957 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1958 1959 // Create an empty block to represent the transition block for looping back 1960 // to the head of the loop. If we have increment code, it will 1961 // go in this block as well. 1962 Block = Succ = TransitionBlock = createBlock(false); 1963 TransitionBlock->setLoopTarget(F); 1964 1965 if (Stmt *I = F->getInc()) { 1966 // Generate increment code in its own basic block. This is the target of 1967 // continue statements. 1968 Succ = addStmt(I); 1969 } 1970 1971 // Finish up the increment (or empty) block if it hasn't been already. 1972 if (Block) { 1973 assert(Block == Succ); 1974 if (badCFG) 1975 return 0; 1976 Block = 0; 1977 } 1978 1979 // The starting block for the loop increment is the block that should 1980 // represent the 'loop target' for looping back to the start of the loop. 1981 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1982 ContinueJumpTarget.block->setLoopTarget(F); 1983 1984 // Loop body should end with destructor of Condition variable (if any). 1985 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1986 1987 // If body is not a compound statement create implicit scope 1988 // and add destructors. 1989 if (!isa<CompoundStmt>(F->getBody())) 1990 addLocalScopeAndDtors(F->getBody()); 1991 1992 // Now populate the body block, and in the process create new blocks as we 1993 // walk the body of the loop. 1994 BodyBlock = addStmt(F->getBody()); 1995 1996 if (!BodyBlock) { 1997 // In the case of "for (...;...;...);" we can have a null BodyBlock. 1998 // Use the continue jump target as the proxy for the body. 1999 BodyBlock = ContinueJumpTarget.block; 2000 } 2001 else if (badCFG) 2002 return 0; 2003 } 2004 2005 // Because of short-circuit evaluation, the condition of the loop can span 2006 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2007 // evaluate the condition. 2008 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0; 2009 2010 do { 2011 Expr *C = F->getCond(); 2012 2013 // Specially handle logical operators, which have a slightly 2014 // more optimal CFG representation. 2015 if (BinaryOperator *Cond = 2016 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : 0)) 2017 if (Cond->isLogicalOp()) { 2018 llvm::tie(EntryConditionBlock, ExitConditionBlock) = 2019 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor); 2020 break; 2021 } 2022 2023 // The default case when not handling logical operators. 2024 EntryConditionBlock = ExitConditionBlock = createBlock(false); 2025 ExitConditionBlock->setTerminator(F); 2026 2027 // See if this is a known constant. 2028 TryResult KnownVal(true); 2029 2030 if (C) { 2031 // Now add the actual condition to the condition block. 2032 // Because the condition itself may contain control-flow, new blocks may 2033 // be created. Thus we update "Succ" after adding the condition. 2034 Block = ExitConditionBlock; 2035 EntryConditionBlock = addStmt(C); 2036 2037 // If this block contains a condition variable, add both the condition 2038 // variable and initializer to the CFG. 2039 if (VarDecl *VD = F->getConditionVariable()) { 2040 if (Expr *Init = VD->getInit()) { 2041 autoCreateBlock(); 2042 appendStmt(Block, F->getConditionVariableDeclStmt()); 2043 EntryConditionBlock = addStmt(Init); 2044 assert(Block == EntryConditionBlock); 2045 } 2046 } 2047 2048 if (Block && badCFG) 2049 return 0; 2050 2051 KnownVal = tryEvaluateBool(C); 2052 } 2053 2054 // Add the loop body entry as a successor to the condition. 2055 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2056 // Link up the condition block with the code that follows the loop. (the 2057 // false branch). 2058 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2059 2060 } while (false); 2061 2062 // Link up the loop-back block to the entry condition block. 2063 addSuccessor(TransitionBlock, EntryConditionBlock); 2064 2065 // The condition block is the implicit successor for any code above the loop. 2066 Succ = EntryConditionBlock; 2067 2068 // If the loop contains initialization, create a new block for those 2069 // statements. This block can also contain statements that precede the loop. 2070 if (Stmt *I = F->getInit()) { 2071 Block = createBlock(); 2072 return addStmt(I); 2073 } 2074 2075 // There is no loop initialization. We are thus basically a while loop. 2076 // NULL out Block to force lazy block construction. 2077 Block = NULL; 2078 Succ = EntryConditionBlock; 2079 return EntryConditionBlock; 2080 } 2081 2082 CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 2083 if (asc.alwaysAdd(*this, M)) { 2084 autoCreateBlock(); 2085 appendStmt(Block, M); 2086 } 2087 return Visit(M->getBase()); 2088 } 2089 2090 CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 2091 // Objective-C fast enumeration 'for' statements: 2092 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 2093 // 2094 // for ( Type newVariable in collection_expression ) { statements } 2095 // 2096 // becomes: 2097 // 2098 // prologue: 2099 // 1. collection_expression 2100 // T. jump to loop_entry 2101 // loop_entry: 2102 // 1. side-effects of element expression 2103 // 1. ObjCForCollectionStmt [performs binding to newVariable] 2104 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 2105 // TB: 2106 // statements 2107 // T. jump to loop_entry 2108 // FB: 2109 // what comes after 2110 // 2111 // and 2112 // 2113 // Type existingItem; 2114 // for ( existingItem in expression ) { statements } 2115 // 2116 // becomes: 2117 // 2118 // the same with newVariable replaced with existingItem; the binding works 2119 // the same except that for one ObjCForCollectionStmt::getElement() returns 2120 // a DeclStmt and the other returns a DeclRefExpr. 2121 // 2122 2123 CFGBlock *LoopSuccessor = 0; 2124 2125 if (Block) { 2126 if (badCFG) 2127 return 0; 2128 LoopSuccessor = Block; 2129 Block = 0; 2130 } else 2131 LoopSuccessor = Succ; 2132 2133 // Build the condition blocks. 2134 CFGBlock *ExitConditionBlock = createBlock(false); 2135 2136 // Set the terminator for the "exit" condition block. 2137 ExitConditionBlock->setTerminator(S); 2138 2139 // The last statement in the block should be the ObjCForCollectionStmt, which 2140 // performs the actual binding to 'element' and determines if there are any 2141 // more items in the collection. 2142 appendStmt(ExitConditionBlock, S); 2143 Block = ExitConditionBlock; 2144 2145 // Walk the 'element' expression to see if there are any side-effects. We 2146 // generate new blocks as necessary. We DON'T add the statement by default to 2147 // the CFG unless it contains control-flow. 2148 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 2149 AddStmtChoice::NotAlwaysAdd); 2150 if (Block) { 2151 if (badCFG) 2152 return 0; 2153 Block = 0; 2154 } 2155 2156 // The condition block is the implicit successor for the loop body as well as 2157 // any code above the loop. 2158 Succ = EntryConditionBlock; 2159 2160 // Now create the true branch. 2161 { 2162 // Save the current values for Succ, continue and break targets. 2163 SaveAndRestore<CFGBlock*> save_Succ(Succ); 2164 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2165 save_break(BreakJumpTarget); 2166 2167 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2168 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2169 2170 CFGBlock *BodyBlock = addStmt(S->getBody()); 2171 2172 if (!BodyBlock) 2173 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 2174 else if (Block) { 2175 if (badCFG) 2176 return 0; 2177 } 2178 2179 // This new body block is a successor to our "exit" condition block. 2180 addSuccessor(ExitConditionBlock, BodyBlock); 2181 } 2182 2183 // Link up the condition block with the code that follows the loop. 2184 // (the false branch). 2185 addSuccessor(ExitConditionBlock, LoopSuccessor); 2186 2187 // Now create a prologue block to contain the collection expression. 2188 Block = createBlock(); 2189 return addStmt(S->getCollection()); 2190 } 2191 2192 CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) { 2193 // Inline the body. 2194 return addStmt(S->getSubStmt()); 2195 // TODO: consider adding cleanups for the end of @autoreleasepool scope. 2196 } 2197 2198 CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 2199 // FIXME: Add locking 'primitives' to CFG for @synchronized. 2200 2201 // Inline the body. 2202 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 2203 2204 // The sync body starts its own basic block. This makes it a little easier 2205 // for diagnostic clients. 2206 if (SyncBlock) { 2207 if (badCFG) 2208 return 0; 2209 2210 Block = 0; 2211 Succ = SyncBlock; 2212 } 2213 2214 // Add the @synchronized to the CFG. 2215 autoCreateBlock(); 2216 appendStmt(Block, S); 2217 2218 // Inline the sync expression. 2219 return addStmt(S->getSynchExpr()); 2220 } 2221 2222 CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 2223 // FIXME 2224 return NYS(); 2225 } 2226 2227 CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) { 2228 autoCreateBlock(); 2229 2230 // Add the PseudoObject as the last thing. 2231 appendStmt(Block, E); 2232 2233 CFGBlock *lastBlock = Block; 2234 2235 // Before that, evaluate all of the semantics in order. In 2236 // CFG-land, that means appending them in reverse order. 2237 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) { 2238 Expr *Semantic = E->getSemanticExpr(--i); 2239 2240 // If the semantic is an opaque value, we're being asked to bind 2241 // it to its source expression. 2242 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic)) 2243 Semantic = OVE->getSourceExpr(); 2244 2245 if (CFGBlock *B = Visit(Semantic)) 2246 lastBlock = B; 2247 } 2248 2249 return lastBlock; 2250 } 2251 2252 CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 2253 CFGBlock *LoopSuccessor = NULL; 2254 2255 // Save local scope position because in case of condition variable ScopePos 2256 // won't be restored when traversing AST. 2257 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2258 2259 // Create local scope for possible condition variable. 2260 // Store scope position for continue statement. 2261 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 2262 if (VarDecl *VD = W->getConditionVariable()) { 2263 addLocalScopeForVarDecl(VD); 2264 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2265 } 2266 2267 // "while" is a control-flow statement. Thus we stop processing the current 2268 // block. 2269 if (Block) { 2270 if (badCFG) 2271 return 0; 2272 LoopSuccessor = Block; 2273 Block = 0; 2274 } else { 2275 LoopSuccessor = Succ; 2276 } 2277 2278 CFGBlock *BodyBlock = 0, *TransitionBlock = 0; 2279 2280 // Process the loop body. 2281 { 2282 assert(W->getBody()); 2283 2284 // Save the current values for Block, Succ, continue and break targets. 2285 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2286 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2287 save_break(BreakJumpTarget); 2288 2289 // Create an empty block to represent the transition block for looping back 2290 // to the head of the loop. 2291 Succ = TransitionBlock = createBlock(false); 2292 TransitionBlock->setLoopTarget(W); 2293 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 2294 2295 // All breaks should go to the code following the loop. 2296 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2297 2298 // Loop body should end with destructor of Condition variable (if any). 2299 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2300 2301 // If body is not a compound statement create implicit scope 2302 // and add destructors. 2303 if (!isa<CompoundStmt>(W->getBody())) 2304 addLocalScopeAndDtors(W->getBody()); 2305 2306 // Create the body. The returned block is the entry to the loop body. 2307 BodyBlock = addStmt(W->getBody()); 2308 2309 if (!BodyBlock) 2310 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2311 else if (Block && badCFG) 2312 return 0; 2313 } 2314 2315 // Because of short-circuit evaluation, the condition of the loop can span 2316 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2317 // evaluate the condition. 2318 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0; 2319 2320 do { 2321 Expr *C = W->getCond(); 2322 2323 // Specially handle logical operators, which have a slightly 2324 // more optimal CFG representation. 2325 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens())) 2326 if (Cond->isLogicalOp()) { 2327 llvm::tie(EntryConditionBlock, ExitConditionBlock) = 2328 VisitLogicalOperator(Cond, W, BodyBlock, 2329 LoopSuccessor); 2330 break; 2331 } 2332 2333 // The default case when not handling logical operators. 2334 ExitConditionBlock = createBlock(false); 2335 ExitConditionBlock->setTerminator(W); 2336 2337 // Now add the actual condition to the condition block. 2338 // Because the condition itself may contain control-flow, new blocks may 2339 // be created. Thus we update "Succ" after adding the condition. 2340 Block = ExitConditionBlock; 2341 Block = EntryConditionBlock = addStmt(C); 2342 2343 // If this block contains a condition variable, add both the condition 2344 // variable and initializer to the CFG. 2345 if (VarDecl *VD = W->getConditionVariable()) { 2346 if (Expr *Init = VD->getInit()) { 2347 autoCreateBlock(); 2348 appendStmt(Block, W->getConditionVariableDeclStmt()); 2349 EntryConditionBlock = addStmt(Init); 2350 assert(Block == EntryConditionBlock); 2351 } 2352 } 2353 2354 if (Block && badCFG) 2355 return 0; 2356 2357 // See if this is a known constant. 2358 const TryResult& KnownVal = tryEvaluateBool(C); 2359 2360 // Add the loop body entry as a successor to the condition. 2361 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2362 // Link up the condition block with the code that follows the loop. (the 2363 // false branch). 2364 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2365 2366 } while(false); 2367 2368 // Link up the loop-back block to the entry condition block. 2369 addSuccessor(TransitionBlock, EntryConditionBlock); 2370 2371 // There can be no more statements in the condition block since we loop back 2372 // to this block. NULL out Block to force lazy creation of another block. 2373 Block = NULL; 2374 2375 // Return the condition block, which is the dominating block for the loop. 2376 Succ = EntryConditionBlock; 2377 return EntryConditionBlock; 2378 } 2379 2380 2381 CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2382 // FIXME: For now we pretend that @catch and the code it contains does not 2383 // exit. 2384 return Block; 2385 } 2386 2387 CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2388 // FIXME: This isn't complete. We basically treat @throw like a return 2389 // statement. 2390 2391 // If we were in the middle of a block we stop processing that block. 2392 if (badCFG) 2393 return 0; 2394 2395 // Create the new block. 2396 Block = createBlock(false); 2397 2398 // The Exit block is the only successor. 2399 addSuccessor(Block, &cfg->getExit()); 2400 2401 // Add the statement to the block. This may create new blocks if S contains 2402 // control-flow (short-circuit operations). 2403 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2404 } 2405 2406 CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2407 // If we were in the middle of a block we stop processing that block. 2408 if (badCFG) 2409 return 0; 2410 2411 // Create the new block. 2412 Block = createBlock(false); 2413 2414 if (TryTerminatedBlock) 2415 // The current try statement is the only successor. 2416 addSuccessor(Block, TryTerminatedBlock); 2417 else 2418 // otherwise the Exit block is the only successor. 2419 addSuccessor(Block, &cfg->getExit()); 2420 2421 // Add the statement to the block. This may create new blocks if S contains 2422 // control-flow (short-circuit operations). 2423 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2424 } 2425 2426 CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2427 CFGBlock *LoopSuccessor = NULL; 2428 2429 // "do...while" is a control-flow statement. Thus we stop processing the 2430 // current block. 2431 if (Block) { 2432 if (badCFG) 2433 return 0; 2434 LoopSuccessor = Block; 2435 } else 2436 LoopSuccessor = Succ; 2437 2438 // Because of short-circuit evaluation, the condition of the loop can span 2439 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2440 // evaluate the condition. 2441 CFGBlock *ExitConditionBlock = createBlock(false); 2442 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2443 2444 // Set the terminator for the "exit" condition block. 2445 ExitConditionBlock->setTerminator(D); 2446 2447 // Now add the actual condition to the condition block. Because the condition 2448 // itself may contain control-flow, new blocks may be created. 2449 if (Stmt *C = D->getCond()) { 2450 Block = ExitConditionBlock; 2451 EntryConditionBlock = addStmt(C); 2452 if (Block) { 2453 if (badCFG) 2454 return 0; 2455 } 2456 } 2457 2458 // The condition block is the implicit successor for the loop body. 2459 Succ = EntryConditionBlock; 2460 2461 // See if this is a known constant. 2462 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2463 2464 // Process the loop body. 2465 CFGBlock *BodyBlock = NULL; 2466 { 2467 assert(D->getBody()); 2468 2469 // Save the current values for Block, Succ, and continue and break targets 2470 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2471 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2472 save_break(BreakJumpTarget); 2473 2474 // All continues within this loop should go to the condition block 2475 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2476 2477 // All breaks should go to the code following the loop. 2478 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2479 2480 // NULL out Block to force lazy instantiation of blocks for the body. 2481 Block = NULL; 2482 2483 // If body is not a compound statement create implicit scope 2484 // and add destructors. 2485 if (!isa<CompoundStmt>(D->getBody())) 2486 addLocalScopeAndDtors(D->getBody()); 2487 2488 // Create the body. The returned block is the entry to the loop body. 2489 BodyBlock = addStmt(D->getBody()); 2490 2491 if (!BodyBlock) 2492 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2493 else if (Block) { 2494 if (badCFG) 2495 return 0; 2496 } 2497 2498 if (!KnownVal.isFalse()) { 2499 // Add an intermediate block between the BodyBlock and the 2500 // ExitConditionBlock to represent the "loop back" transition. Create an 2501 // empty block to represent the transition block for looping back to the 2502 // head of the loop. 2503 // FIXME: Can we do this more efficiently without adding another block? 2504 Block = NULL; 2505 Succ = BodyBlock; 2506 CFGBlock *LoopBackBlock = createBlock(); 2507 LoopBackBlock->setLoopTarget(D); 2508 2509 // Add the loop body entry as a successor to the condition. 2510 addSuccessor(ExitConditionBlock, LoopBackBlock); 2511 } 2512 else 2513 addSuccessor(ExitConditionBlock, NULL); 2514 } 2515 2516 // Link up the condition block with the code that follows the loop. 2517 // (the false branch). 2518 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2519 2520 // There can be no more statements in the body block(s) since we loop back to 2521 // the body. NULL out Block to force lazy creation of another block. 2522 Block = NULL; 2523 2524 // Return the loop body, which is the dominating block for the loop. 2525 Succ = BodyBlock; 2526 return BodyBlock; 2527 } 2528 2529 CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2530 // "continue" is a control-flow statement. Thus we stop processing the 2531 // current block. 2532 if (badCFG) 2533 return 0; 2534 2535 // Now create a new block that ends with the continue statement. 2536 Block = createBlock(false); 2537 Block->setTerminator(C); 2538 2539 // If there is no target for the continue, then we are looking at an 2540 // incomplete AST. This means the CFG cannot be constructed. 2541 if (ContinueJumpTarget.block) { 2542 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2543 addSuccessor(Block, ContinueJumpTarget.block); 2544 } else 2545 badCFG = true; 2546 2547 return Block; 2548 } 2549 2550 CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2551 AddStmtChoice asc) { 2552 2553 if (asc.alwaysAdd(*this, E)) { 2554 autoCreateBlock(); 2555 appendStmt(Block, E); 2556 } 2557 2558 // VLA types have expressions that must be evaluated. 2559 CFGBlock *lastBlock = Block; 2560 2561 if (E->isArgumentType()) { 2562 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2563 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2564 lastBlock = addStmt(VA->getSizeExpr()); 2565 } 2566 return lastBlock; 2567 } 2568 2569 /// VisitStmtExpr - Utility method to handle (nested) statement 2570 /// expressions (a GCC extension). 2571 CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2572 if (asc.alwaysAdd(*this, SE)) { 2573 autoCreateBlock(); 2574 appendStmt(Block, SE); 2575 } 2576 return VisitCompoundStmt(SE->getSubStmt()); 2577 } 2578 2579 CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2580 // "switch" is a control-flow statement. Thus we stop processing the current 2581 // block. 2582 CFGBlock *SwitchSuccessor = NULL; 2583 2584 // Save local scope position because in case of condition variable ScopePos 2585 // won't be restored when traversing AST. 2586 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2587 2588 // Create local scope for possible condition variable. 2589 // Store scope position. Add implicit destructor. 2590 if (VarDecl *VD = Terminator->getConditionVariable()) { 2591 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2592 addLocalScopeForVarDecl(VD); 2593 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2594 } 2595 2596 if (Block) { 2597 if (badCFG) 2598 return 0; 2599 SwitchSuccessor = Block; 2600 } else SwitchSuccessor = Succ; 2601 2602 // Save the current "switch" context. 2603 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2604 save_default(DefaultCaseBlock); 2605 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2606 2607 // Set the "default" case to be the block after the switch statement. If the 2608 // switch statement contains a "default:", this value will be overwritten with 2609 // the block for that code. 2610 DefaultCaseBlock = SwitchSuccessor; 2611 2612 // Create a new block that will contain the switch statement. 2613 SwitchTerminatedBlock = createBlock(false); 2614 2615 // Now process the switch body. The code after the switch is the implicit 2616 // successor. 2617 Succ = SwitchSuccessor; 2618 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2619 2620 // When visiting the body, the case statements should automatically get linked 2621 // up to the switch. We also don't keep a pointer to the body, since all 2622 // control-flow from the switch goes to case/default statements. 2623 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2624 Block = NULL; 2625 2626 // For pruning unreachable case statements, save the current state 2627 // for tracking the condition value. 2628 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2629 false); 2630 2631 // Determine if the switch condition can be explicitly evaluated. 2632 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2633 Expr::EvalResult result; 2634 bool b = tryEvaluate(Terminator->getCond(), result); 2635 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2636 b ? &result : 0); 2637 2638 // If body is not a compound statement create implicit scope 2639 // and add destructors. 2640 if (!isa<CompoundStmt>(Terminator->getBody())) 2641 addLocalScopeAndDtors(Terminator->getBody()); 2642 2643 addStmt(Terminator->getBody()); 2644 if (Block) { 2645 if (badCFG) 2646 return 0; 2647 } 2648 2649 // If we have no "default:" case, the default transition is to the code 2650 // following the switch body. Moreover, take into account if all the 2651 // cases of a switch are covered (e.g., switching on an enum value). 2652 addSuccessor(SwitchTerminatedBlock, 2653 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2654 ? 0 : DefaultCaseBlock); 2655 2656 // Add the terminator and condition in the switch block. 2657 SwitchTerminatedBlock->setTerminator(Terminator); 2658 Block = SwitchTerminatedBlock; 2659 CFGBlock *LastBlock = addStmt(Terminator->getCond()); 2660 2661 // Finally, if the SwitchStmt contains a condition variable, add both the 2662 // SwitchStmt and the condition variable initialization to the CFG. 2663 if (VarDecl *VD = Terminator->getConditionVariable()) { 2664 if (Expr *Init = VD->getInit()) { 2665 autoCreateBlock(); 2666 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2667 LastBlock = addStmt(Init); 2668 } 2669 } 2670 2671 return LastBlock; 2672 } 2673 2674 static bool shouldAddCase(bool &switchExclusivelyCovered, 2675 const Expr::EvalResult *switchCond, 2676 const CaseStmt *CS, 2677 ASTContext &Ctx) { 2678 if (!switchCond) 2679 return true; 2680 2681 bool addCase = false; 2682 2683 if (!switchExclusivelyCovered) { 2684 if (switchCond->Val.isInt()) { 2685 // Evaluate the LHS of the case value. 2686 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2687 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2688 2689 if (condInt == lhsInt) { 2690 addCase = true; 2691 switchExclusivelyCovered = true; 2692 } 2693 else if (condInt < lhsInt) { 2694 if (const Expr *RHS = CS->getRHS()) { 2695 // Evaluate the RHS of the case value. 2696 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2697 if (V2 <= condInt) { 2698 addCase = true; 2699 switchExclusivelyCovered = true; 2700 } 2701 } 2702 } 2703 } 2704 else 2705 addCase = true; 2706 } 2707 return addCase; 2708 } 2709 2710 CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2711 // CaseStmts are essentially labels, so they are the first statement in a 2712 // block. 2713 CFGBlock *TopBlock = 0, *LastBlock = 0; 2714 2715 if (Stmt *Sub = CS->getSubStmt()) { 2716 // For deeply nested chains of CaseStmts, instead of doing a recursion 2717 // (which can blow out the stack), manually unroll and create blocks 2718 // along the way. 2719 while (isa<CaseStmt>(Sub)) { 2720 CFGBlock *currentBlock = createBlock(false); 2721 currentBlock->setLabel(CS); 2722 2723 if (TopBlock) 2724 addSuccessor(LastBlock, currentBlock); 2725 else 2726 TopBlock = currentBlock; 2727 2728 addSuccessor(SwitchTerminatedBlock, 2729 shouldAddCase(switchExclusivelyCovered, switchCond, 2730 CS, *Context) 2731 ? currentBlock : 0); 2732 2733 LastBlock = currentBlock; 2734 CS = cast<CaseStmt>(Sub); 2735 Sub = CS->getSubStmt(); 2736 } 2737 2738 addStmt(Sub); 2739 } 2740 2741 CFGBlock *CaseBlock = Block; 2742 if (!CaseBlock) 2743 CaseBlock = createBlock(); 2744 2745 // Cases statements partition blocks, so this is the top of the basic block we 2746 // were processing (the "case XXX:" is the label). 2747 CaseBlock->setLabel(CS); 2748 2749 if (badCFG) 2750 return 0; 2751 2752 // Add this block to the list of successors for the block with the switch 2753 // statement. 2754 assert(SwitchTerminatedBlock); 2755 addSuccessor(SwitchTerminatedBlock, 2756 shouldAddCase(switchExclusivelyCovered, switchCond, 2757 CS, *Context) 2758 ? CaseBlock : 0); 2759 2760 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2761 Block = NULL; 2762 2763 if (TopBlock) { 2764 addSuccessor(LastBlock, CaseBlock); 2765 Succ = TopBlock; 2766 } else { 2767 // This block is now the implicit successor of other blocks. 2768 Succ = CaseBlock; 2769 } 2770 2771 return Succ; 2772 } 2773 2774 CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2775 if (Terminator->getSubStmt()) 2776 addStmt(Terminator->getSubStmt()); 2777 2778 DefaultCaseBlock = Block; 2779 2780 if (!DefaultCaseBlock) 2781 DefaultCaseBlock = createBlock(); 2782 2783 // Default statements partition blocks, so this is the top of the basic block 2784 // we were processing (the "default:" is the label). 2785 DefaultCaseBlock->setLabel(Terminator); 2786 2787 if (badCFG) 2788 return 0; 2789 2790 // Unlike case statements, we don't add the default block to the successors 2791 // for the switch statement immediately. This is done when we finish 2792 // processing the switch statement. This allows for the default case 2793 // (including a fall-through to the code after the switch statement) to always 2794 // be the last successor of a switch-terminated block. 2795 2796 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2797 Block = NULL; 2798 2799 // This block is now the implicit successor of other blocks. 2800 Succ = DefaultCaseBlock; 2801 2802 return DefaultCaseBlock; 2803 } 2804 2805 CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2806 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2807 // current block. 2808 CFGBlock *TrySuccessor = NULL; 2809 2810 if (Block) { 2811 if (badCFG) 2812 return 0; 2813 TrySuccessor = Block; 2814 } else TrySuccessor = Succ; 2815 2816 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2817 2818 // Create a new block that will contain the try statement. 2819 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2820 // Add the terminator in the try block. 2821 NewTryTerminatedBlock->setTerminator(Terminator); 2822 2823 bool HasCatchAll = false; 2824 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2825 // The code after the try is the implicit successor. 2826 Succ = TrySuccessor; 2827 CXXCatchStmt *CS = Terminator->getHandler(h); 2828 if (CS->getExceptionDecl() == 0) { 2829 HasCatchAll = true; 2830 } 2831 Block = NULL; 2832 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2833 if (CatchBlock == 0) 2834 return 0; 2835 // Add this block to the list of successors for the block with the try 2836 // statement. 2837 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2838 } 2839 if (!HasCatchAll) { 2840 if (PrevTryTerminatedBlock) 2841 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2842 else 2843 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2844 } 2845 2846 // The code after the try is the implicit successor. 2847 Succ = TrySuccessor; 2848 2849 // Save the current "try" context. 2850 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2851 cfg->addTryDispatchBlock(TryTerminatedBlock); 2852 2853 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2854 Block = NULL; 2855 return addStmt(Terminator->getTryBlock()); 2856 } 2857 2858 CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2859 // CXXCatchStmt are treated like labels, so they are the first statement in a 2860 // block. 2861 2862 // Save local scope position because in case of exception variable ScopePos 2863 // won't be restored when traversing AST. 2864 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2865 2866 // Create local scope for possible exception variable. 2867 // Store scope position. Add implicit destructor. 2868 if (VarDecl *VD = CS->getExceptionDecl()) { 2869 LocalScope::const_iterator BeginScopePos = ScopePos; 2870 addLocalScopeForVarDecl(VD); 2871 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2872 } 2873 2874 if (CS->getHandlerBlock()) 2875 addStmt(CS->getHandlerBlock()); 2876 2877 CFGBlock *CatchBlock = Block; 2878 if (!CatchBlock) 2879 CatchBlock = createBlock(); 2880 2881 // CXXCatchStmt is more than just a label. They have semantic meaning 2882 // as well, as they implicitly "initialize" the catch variable. Add 2883 // it to the CFG as a CFGElement so that the control-flow of these 2884 // semantics gets captured. 2885 appendStmt(CatchBlock, CS); 2886 2887 // Also add the CXXCatchStmt as a label, to mirror handling of regular 2888 // labels. 2889 CatchBlock->setLabel(CS); 2890 2891 // Bail out if the CFG is bad. 2892 if (badCFG) 2893 return 0; 2894 2895 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2896 Block = NULL; 2897 2898 return CatchBlock; 2899 } 2900 2901 CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2902 // C++0x for-range statements are specified as [stmt.ranged]: 2903 // 2904 // { 2905 // auto && __range = range-init; 2906 // for ( auto __begin = begin-expr, 2907 // __end = end-expr; 2908 // __begin != __end; 2909 // ++__begin ) { 2910 // for-range-declaration = *__begin; 2911 // statement 2912 // } 2913 // } 2914 2915 // Save local scope position before the addition of the implicit variables. 2916 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2917 2918 // Create local scopes and destructors for range, begin and end variables. 2919 if (Stmt *Range = S->getRangeStmt()) 2920 addLocalScopeForStmt(Range); 2921 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2922 addLocalScopeForStmt(BeginEnd); 2923 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2924 2925 LocalScope::const_iterator ContinueScopePos = ScopePos; 2926 2927 // "for" is a control-flow statement. Thus we stop processing the current 2928 // block. 2929 CFGBlock *LoopSuccessor = NULL; 2930 if (Block) { 2931 if (badCFG) 2932 return 0; 2933 LoopSuccessor = Block; 2934 } else 2935 LoopSuccessor = Succ; 2936 2937 // Save the current value for the break targets. 2938 // All breaks should go to the code following the loop. 2939 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2940 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2941 2942 // The block for the __begin != __end expression. 2943 CFGBlock *ConditionBlock = createBlock(false); 2944 ConditionBlock->setTerminator(S); 2945 2946 // Now add the actual condition to the condition block. 2947 if (Expr *C = S->getCond()) { 2948 Block = ConditionBlock; 2949 CFGBlock *BeginConditionBlock = addStmt(C); 2950 if (badCFG) 2951 return 0; 2952 assert(BeginConditionBlock == ConditionBlock && 2953 "condition block in for-range was unexpectedly complex"); 2954 (void)BeginConditionBlock; 2955 } 2956 2957 // The condition block is the implicit successor for the loop body as well as 2958 // any code above the loop. 2959 Succ = ConditionBlock; 2960 2961 // See if this is a known constant. 2962 TryResult KnownVal(true); 2963 2964 if (S->getCond()) 2965 KnownVal = tryEvaluateBool(S->getCond()); 2966 2967 // Now create the loop body. 2968 { 2969 assert(S->getBody()); 2970 2971 // Save the current values for Block, Succ, and continue targets. 2972 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2973 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2974 2975 // Generate increment code in its own basic block. This is the target of 2976 // continue statements. 2977 Block = 0; 2978 Succ = addStmt(S->getInc()); 2979 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2980 2981 // The starting block for the loop increment is the block that should 2982 // represent the 'loop target' for looping back to the start of the loop. 2983 ContinueJumpTarget.block->setLoopTarget(S); 2984 2985 // Finish up the increment block and prepare to start the loop body. 2986 assert(Block); 2987 if (badCFG) 2988 return 0; 2989 Block = 0; 2990 2991 2992 // Add implicit scope and dtors for loop variable. 2993 addLocalScopeAndDtors(S->getLoopVarStmt()); 2994 2995 // Populate a new block to contain the loop body and loop variable. 2996 addStmt(S->getBody()); 2997 if (badCFG) 2998 return 0; 2999 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt()); 3000 if (badCFG) 3001 return 0; 3002 3003 // This new body block is a successor to our condition block. 3004 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : LoopVarStmtBlock); 3005 } 3006 3007 // Link up the condition block with the code that follows the loop (the 3008 // false branch). 3009 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 3010 3011 // Add the initialization statements. 3012 Block = createBlock(); 3013 addStmt(S->getBeginEndStmt()); 3014 return addStmt(S->getRangeStmt()); 3015 } 3016 3017 CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 3018 AddStmtChoice asc) { 3019 if (BuildOpts.AddTemporaryDtors) { 3020 // If adding implicit destructors visit the full expression for adding 3021 // destructors of temporaries. 3022 VisitForTemporaryDtors(E->getSubExpr()); 3023 3024 // Full expression has to be added as CFGStmt so it will be sequenced 3025 // before destructors of it's temporaries. 3026 asc = asc.withAlwaysAdd(true); 3027 } 3028 return Visit(E->getSubExpr(), asc); 3029 } 3030 3031 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 3032 AddStmtChoice asc) { 3033 if (asc.alwaysAdd(*this, E)) { 3034 autoCreateBlock(); 3035 appendStmt(Block, E); 3036 3037 // We do not want to propagate the AlwaysAdd property. 3038 asc = asc.withAlwaysAdd(false); 3039 } 3040 return Visit(E->getSubExpr(), asc); 3041 } 3042 3043 CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 3044 AddStmtChoice asc) { 3045 autoCreateBlock(); 3046 appendStmt(Block, C); 3047 3048 return VisitChildren(C); 3049 } 3050 3051 CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 3052 AddStmtChoice asc) { 3053 if (asc.alwaysAdd(*this, E)) { 3054 autoCreateBlock(); 3055 appendStmt(Block, E); 3056 // We do not want to propagate the AlwaysAdd property. 3057 asc = asc.withAlwaysAdd(false); 3058 } 3059 return Visit(E->getSubExpr(), asc); 3060 } 3061 3062 CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 3063 AddStmtChoice asc) { 3064 autoCreateBlock(); 3065 appendStmt(Block, C); 3066 return VisitChildren(C); 3067 } 3068 3069 CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 3070 AddStmtChoice asc) { 3071 if (asc.alwaysAdd(*this, E)) { 3072 autoCreateBlock(); 3073 appendStmt(Block, E); 3074 } 3075 return Visit(E->getSubExpr(), AddStmtChoice()); 3076 } 3077 3078 CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3079 // Lazily create the indirect-goto dispatch block if there isn't one already. 3080 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 3081 3082 if (!IBlock) { 3083 IBlock = createBlock(false); 3084 cfg->setIndirectGotoBlock(IBlock); 3085 } 3086 3087 // IndirectGoto is a control-flow statement. Thus we stop processing the 3088 // current block and create a new one. 3089 if (badCFG) 3090 return 0; 3091 3092 Block = createBlock(false); 3093 Block->setTerminator(I); 3094 addSuccessor(Block, IBlock); 3095 return addStmt(I->getTarget()); 3096 } 3097 3098 CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 3099 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors); 3100 3101 tryAgain: 3102 if (!E) { 3103 badCFG = true; 3104 return NULL; 3105 } 3106 switch (E->getStmtClass()) { 3107 default: 3108 return VisitChildrenForTemporaryDtors(E); 3109 3110 case Stmt::BinaryOperatorClass: 3111 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 3112 3113 case Stmt::CXXBindTemporaryExprClass: 3114 return VisitCXXBindTemporaryExprForTemporaryDtors( 3115 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 3116 3117 case Stmt::BinaryConditionalOperatorClass: 3118 case Stmt::ConditionalOperatorClass: 3119 return VisitConditionalOperatorForTemporaryDtors( 3120 cast<AbstractConditionalOperator>(E), BindToTemporary); 3121 3122 case Stmt::ImplicitCastExprClass: 3123 // For implicit cast we want BindToTemporary to be passed further. 3124 E = cast<CastExpr>(E)->getSubExpr(); 3125 goto tryAgain; 3126 3127 case Stmt::ParenExprClass: 3128 E = cast<ParenExpr>(E)->getSubExpr(); 3129 goto tryAgain; 3130 3131 case Stmt::MaterializeTemporaryExprClass: 3132 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 3133 goto tryAgain; 3134 } 3135 } 3136 3137 CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 3138 // When visiting children for destructors we want to visit them in reverse 3139 // order that they will appear in the CFG. Because the CFG is built 3140 // bottom-up, this means we visit them in their natural order, which 3141 // reverses them in the CFG. 3142 CFGBlock *B = Block; 3143 for (Stmt::child_range I = E->children(); I; ++I) { 3144 if (Stmt *Child = *I) 3145 if (CFGBlock *R = VisitForTemporaryDtors(Child)) 3146 B = R; 3147 } 3148 return B; 3149 } 3150 3151 CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 3152 if (E->isLogicalOp()) { 3153 // Destructors for temporaries in LHS expression should be called after 3154 // those for RHS expression. Even if this will unnecessarily create a block, 3155 // this block will be used at least by the full expression. 3156 autoCreateBlock(); 3157 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 3158 if (badCFG) 3159 return NULL; 3160 3161 Succ = ConfluenceBlock; 3162 Block = NULL; 3163 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3164 3165 if (RHSBlock) { 3166 if (badCFG) 3167 return NULL; 3168 3169 // If RHS expression did produce destructors we need to connect created 3170 // blocks to CFG in same manner as for binary operator itself. 3171 CFGBlock *LHSBlock = createBlock(false); 3172 LHSBlock->setTerminator(CFGTerminator(E, true)); 3173 3174 // For binary operator LHS block is before RHS in list of predecessors 3175 // of ConfluenceBlock. 3176 std::reverse(ConfluenceBlock->pred_begin(), 3177 ConfluenceBlock->pred_end()); 3178 3179 // See if this is a known constant. 3180 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 3181 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 3182 KnownVal.negate(); 3183 3184 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 3185 // itself. 3186 if (E->getOpcode() == BO_LOr) { 3187 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3188 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3189 } else { 3190 assert (E->getOpcode() == BO_LAnd); 3191 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3192 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3193 } 3194 3195 Block = LHSBlock; 3196 return LHSBlock; 3197 } 3198 3199 Block = ConfluenceBlock; 3200 return ConfluenceBlock; 3201 } 3202 3203 if (E->isAssignmentOp()) { 3204 // For assignment operator (=) LHS expression is visited 3205 // before RHS expression. For destructors visit them in reverse order. 3206 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3207 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3208 return LHSBlock ? LHSBlock : RHSBlock; 3209 } 3210 3211 // For any other binary operator RHS expression is visited before 3212 // LHS expression (order of children). For destructors visit them in reverse 3213 // order. 3214 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3215 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3216 return RHSBlock ? RHSBlock : LHSBlock; 3217 } 3218 3219 CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 3220 CXXBindTemporaryExpr *E, bool BindToTemporary) { 3221 // First add destructors for temporaries in subexpression. 3222 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 3223 if (!BindToTemporary) { 3224 // If lifetime of temporary is not prolonged (by assigning to constant 3225 // reference) add destructor for it. 3226 3227 // If the destructor is marked as a no-return destructor, we need to create 3228 // a new block for the destructor which does not have as a successor 3229 // anything built thus far. Control won't flow out of this block. 3230 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 3231 if (Dtor->isNoReturn()) 3232 Block = createNoReturnBlock(); 3233 else 3234 autoCreateBlock(); 3235 3236 appendTemporaryDtor(Block, E); 3237 B = Block; 3238 } 3239 return B; 3240 } 3241 3242 CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 3243 AbstractConditionalOperator *E, bool BindToTemporary) { 3244 // First add destructors for condition expression. Even if this will 3245 // unnecessarily create a block, this block will be used at least by the full 3246 // expression. 3247 autoCreateBlock(); 3248 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 3249 if (badCFG) 3250 return NULL; 3251 if (BinaryConditionalOperator *BCO 3252 = dyn_cast<BinaryConditionalOperator>(E)) { 3253 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 3254 if (badCFG) 3255 return NULL; 3256 } 3257 3258 // Try to add block with destructors for LHS expression. 3259 CFGBlock *LHSBlock = NULL; 3260 Succ = ConfluenceBlock; 3261 Block = NULL; 3262 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 3263 if (badCFG) 3264 return NULL; 3265 3266 // Try to add block with destructors for RHS expression; 3267 Succ = ConfluenceBlock; 3268 Block = NULL; 3269 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 3270 BindToTemporary); 3271 if (badCFG) 3272 return NULL; 3273 3274 if (!RHSBlock && !LHSBlock) { 3275 // If neither LHS nor RHS expression had temporaries to destroy don't create 3276 // more blocks. 3277 Block = ConfluenceBlock; 3278 return Block; 3279 } 3280 3281 Block = createBlock(false); 3282 Block->setTerminator(CFGTerminator(E, true)); 3283 3284 // See if this is a known constant. 3285 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 3286 3287 if (LHSBlock) { 3288 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 3289 } else if (KnownVal.isFalse()) { 3290 addSuccessor(Block, NULL); 3291 } else { 3292 addSuccessor(Block, ConfluenceBlock); 3293 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 3294 } 3295 3296 if (!RHSBlock) 3297 RHSBlock = ConfluenceBlock; 3298 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 3299 3300 return Block; 3301 } 3302 3303 } // end anonymous namespace 3304 3305 /// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 3306 /// no successors or predecessors. If this is the first block created in the 3307 /// CFG, it is automatically set to be the Entry and Exit of the CFG. 3308 CFGBlock *CFG::createBlock() { 3309 bool first_block = begin() == end(); 3310 3311 // Create the block. 3312 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 3313 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this); 3314 Blocks.push_back(Mem, BlkBVC); 3315 3316 // If this is the first block, set it as the Entry and Exit. 3317 if (first_block) 3318 Entry = Exit = &back(); 3319 3320 // Return the block. 3321 return &back(); 3322 } 3323 3324 /// buildCFG - Constructs a CFG from an AST. Ownership of the returned 3325 /// CFG is returned to the caller. 3326 CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 3327 const BuildOptions &BO) { 3328 CFGBuilder Builder(C, BO); 3329 return Builder.buildCFG(D, Statement); 3330 } 3331 3332 const CXXDestructorDecl * 3333 CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 3334 switch (getKind()) { 3335 case CFGElement::Statement: 3336 case CFGElement::Initializer: 3337 llvm_unreachable("getDestructorDecl should only be used with " 3338 "ImplicitDtors"); 3339 case CFGElement::AutomaticObjectDtor: { 3340 const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl(); 3341 QualType ty = var->getType(); 3342 ty = ty.getNonReferenceType(); 3343 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3344 ty = arrayType->getElementType(); 3345 } 3346 const RecordType *recordType = ty->getAs<RecordType>(); 3347 const CXXRecordDecl *classDecl = 3348 cast<CXXRecordDecl>(recordType->getDecl()); 3349 return classDecl->getDestructor(); 3350 } 3351 case CFGElement::TemporaryDtor: { 3352 const CXXBindTemporaryExpr *bindExpr = 3353 castAs<CFGTemporaryDtor>().getBindTemporaryExpr(); 3354 const CXXTemporary *temp = bindExpr->getTemporary(); 3355 return temp->getDestructor(); 3356 } 3357 case CFGElement::BaseDtor: 3358 case CFGElement::MemberDtor: 3359 3360 // Not yet supported. 3361 return 0; 3362 } 3363 llvm_unreachable("getKind() returned bogus value"); 3364 } 3365 3366 bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3367 if (const CXXDestructorDecl *DD = getDestructorDecl(astContext)) 3368 return DD->isNoReturn(); 3369 return false; 3370 } 3371 3372 //===----------------------------------------------------------------------===// 3373 // CFG: Queries for BlkExprs. 3374 //===----------------------------------------------------------------------===// 3375 3376 namespace { 3377 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3378 } 3379 3380 static void FindSubExprAssignments(const Stmt *S, 3381 llvm::SmallPtrSet<const Expr*,50>& Set) { 3382 if (!S) 3383 return; 3384 3385 for (Stmt::const_child_range I = S->children(); I; ++I) { 3386 const Stmt *child = *I; 3387 if (!child) 3388 continue; 3389 3390 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3391 if (B->isAssignmentOp()) Set.insert(B); 3392 3393 FindSubExprAssignments(child, Set); 3394 } 3395 } 3396 3397 static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3398 BlkExprMapTy* M = new BlkExprMapTy(); 3399 3400 // Look for assignments that are used as subexpressions. These are the only 3401 // assignments that we want to *possibly* register as a block-level 3402 // expression. Basically, if an assignment occurs both in a subexpression and 3403 // at the block-level, it is a block-level expression. 3404 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3405 3406 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3407 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3408 if (Optional<CFGStmt> S = BI->getAs<CFGStmt>()) 3409 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3410 3411 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3412 3413 // Iterate over the statements again on identify the Expr* and Stmt* at the 3414 // block-level that are block-level expressions. 3415 3416 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3417 Optional<CFGStmt> CS = BI->getAs<CFGStmt>(); 3418 if (!CS) 3419 continue; 3420 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3421 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3422 3423 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3424 // Assignment expressions that are not nested within another 3425 // expression are really "statements" whose value is never used by 3426 // another expression. 3427 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3428 continue; 3429 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3430 // Special handling for statement expressions. The last statement in 3431 // the statement expression is also a block-level expr. 3432 const CompoundStmt *C = SE->getSubStmt(); 3433 if (!C->body_empty()) { 3434 const Stmt *Last = C->body_back(); 3435 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3436 Last = LastEx->IgnoreParens(); 3437 unsigned x = M->size(); 3438 (*M)[Last] = x; 3439 } 3440 } 3441 3442 unsigned x = M->size(); 3443 (*M)[Exp] = x; 3444 } 3445 } 3446 3447 // Look at terminators. The condition is a block-level expression. 3448 3449 Stmt *S = (*I)->getTerminatorCondition(); 3450 3451 if (S && M->find(S) == M->end()) { 3452 unsigned x = M->size(); 3453 (*M)[S] = x; 3454 } 3455 } 3456 3457 return M; 3458 } 3459 3460 CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3461 assert(S != NULL); 3462 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3463 3464 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3465 BlkExprMapTy::iterator I = M->find(S); 3466 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3467 } 3468 3469 unsigned CFG::getNumBlkExprs() { 3470 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3471 return M->size(); 3472 3473 // We assume callers interested in the number of BlkExprs will want 3474 // the map constructed if it doesn't already exist. 3475 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3476 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3477 } 3478 3479 //===----------------------------------------------------------------------===// 3480 // Filtered walking of the CFG. 3481 //===----------------------------------------------------------------------===// 3482 3483 bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3484 const CFGBlock *From, const CFGBlock *To) { 3485 3486 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3487 // If the 'To' has no label or is labeled but the label isn't a 3488 // CaseStmt then filter this edge. 3489 if (const SwitchStmt *S = 3490 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3491 if (S->isAllEnumCasesCovered()) { 3492 const Stmt *L = To->getLabel(); 3493 if (!L || !isa<CaseStmt>(L)) 3494 return true; 3495 } 3496 } 3497 } 3498 3499 return false; 3500 } 3501 3502 //===----------------------------------------------------------------------===// 3503 // Cleanup: CFG dstor. 3504 //===----------------------------------------------------------------------===// 3505 3506 CFG::~CFG() { 3507 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3508 } 3509 3510 //===----------------------------------------------------------------------===// 3511 // CFG pretty printing 3512 //===----------------------------------------------------------------------===// 3513 3514 namespace { 3515 3516 class StmtPrinterHelper : public PrinterHelper { 3517 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3518 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3519 StmtMapTy StmtMap; 3520 DeclMapTy DeclMap; 3521 signed currentBlock; 3522 unsigned currStmt; 3523 const LangOptions &LangOpts; 3524 public: 3525 3526 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3527 : currentBlock(0), currStmt(0), LangOpts(LO) 3528 { 3529 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3530 unsigned j = 1; 3531 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3532 BI != BEnd; ++BI, ++j ) { 3533 if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) { 3534 const Stmt *stmt= SE->getStmt(); 3535 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3536 StmtMap[stmt] = P; 3537 3538 switch (stmt->getStmtClass()) { 3539 case Stmt::DeclStmtClass: 3540 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3541 break; 3542 case Stmt::IfStmtClass: { 3543 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3544 if (var) 3545 DeclMap[var] = P; 3546 break; 3547 } 3548 case Stmt::ForStmtClass: { 3549 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3550 if (var) 3551 DeclMap[var] = P; 3552 break; 3553 } 3554 case Stmt::WhileStmtClass: { 3555 const VarDecl *var = 3556 cast<WhileStmt>(stmt)->getConditionVariable(); 3557 if (var) 3558 DeclMap[var] = P; 3559 break; 3560 } 3561 case Stmt::SwitchStmtClass: { 3562 const VarDecl *var = 3563 cast<SwitchStmt>(stmt)->getConditionVariable(); 3564 if (var) 3565 DeclMap[var] = P; 3566 break; 3567 } 3568 case Stmt::CXXCatchStmtClass: { 3569 const VarDecl *var = 3570 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3571 if (var) 3572 DeclMap[var] = P; 3573 break; 3574 } 3575 default: 3576 break; 3577 } 3578 } 3579 } 3580 } 3581 } 3582 3583 3584 virtual ~StmtPrinterHelper() {} 3585 3586 const LangOptions &getLangOpts() const { return LangOpts; } 3587 void setBlockID(signed i) { currentBlock = i; } 3588 void setStmtID(unsigned i) { currStmt = i; } 3589 3590 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3591 StmtMapTy::iterator I = StmtMap.find(S); 3592 3593 if (I == StmtMap.end()) 3594 return false; 3595 3596 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3597 && I->second.second == currStmt) { 3598 return false; 3599 } 3600 3601 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3602 return true; 3603 } 3604 3605 bool handleDecl(const Decl *D, raw_ostream &OS) { 3606 DeclMapTy::iterator I = DeclMap.find(D); 3607 3608 if (I == DeclMap.end()) 3609 return false; 3610 3611 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3612 && I->second.second == currStmt) { 3613 return false; 3614 } 3615 3616 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3617 return true; 3618 } 3619 }; 3620 } // end anonymous namespace 3621 3622 3623 namespace { 3624 class CFGBlockTerminatorPrint 3625 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3626 3627 raw_ostream &OS; 3628 StmtPrinterHelper* Helper; 3629 PrintingPolicy Policy; 3630 public: 3631 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3632 const PrintingPolicy &Policy) 3633 : OS(os), Helper(helper), Policy(Policy) {} 3634 3635 void VisitIfStmt(IfStmt *I) { 3636 OS << "if "; 3637 I->getCond()->printPretty(OS,Helper,Policy); 3638 } 3639 3640 // Default case. 3641 void VisitStmt(Stmt *Terminator) { 3642 Terminator->printPretty(OS, Helper, Policy); 3643 } 3644 3645 void VisitForStmt(ForStmt *F) { 3646 OS << "for (" ; 3647 if (F->getInit()) 3648 OS << "..."; 3649 OS << "; "; 3650 if (Stmt *C = F->getCond()) 3651 C->printPretty(OS, Helper, Policy); 3652 OS << "; "; 3653 if (F->getInc()) 3654 OS << "..."; 3655 OS << ")"; 3656 } 3657 3658 void VisitWhileStmt(WhileStmt *W) { 3659 OS << "while " ; 3660 if (Stmt *C = W->getCond()) 3661 C->printPretty(OS, Helper, Policy); 3662 } 3663 3664 void VisitDoStmt(DoStmt *D) { 3665 OS << "do ... while "; 3666 if (Stmt *C = D->getCond()) 3667 C->printPretty(OS, Helper, Policy); 3668 } 3669 3670 void VisitSwitchStmt(SwitchStmt *Terminator) { 3671 OS << "switch "; 3672 Terminator->getCond()->printPretty(OS, Helper, Policy); 3673 } 3674 3675 void VisitCXXTryStmt(CXXTryStmt *CS) { 3676 OS << "try ..."; 3677 } 3678 3679 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3680 C->getCond()->printPretty(OS, Helper, Policy); 3681 OS << " ? ... : ..."; 3682 } 3683 3684 void VisitChooseExpr(ChooseExpr *C) { 3685 OS << "__builtin_choose_expr( "; 3686 C->getCond()->printPretty(OS, Helper, Policy); 3687 OS << " )"; 3688 } 3689 3690 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3691 OS << "goto *"; 3692 I->getTarget()->printPretty(OS, Helper, Policy); 3693 } 3694 3695 void VisitBinaryOperator(BinaryOperator* B) { 3696 if (!B->isLogicalOp()) { 3697 VisitExpr(B); 3698 return; 3699 } 3700 3701 B->getLHS()->printPretty(OS, Helper, Policy); 3702 3703 switch (B->getOpcode()) { 3704 case BO_LOr: 3705 OS << " || ..."; 3706 return; 3707 case BO_LAnd: 3708 OS << " && ..."; 3709 return; 3710 default: 3711 llvm_unreachable("Invalid logical operator."); 3712 } 3713 } 3714 3715 void VisitExpr(Expr *E) { 3716 E->printPretty(OS, Helper, Policy); 3717 } 3718 }; 3719 } // end anonymous namespace 3720 3721 static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3722 const CFGElement &E) { 3723 if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) { 3724 const Stmt *S = CS->getStmt(); 3725 3726 if (Helper) { 3727 3728 // special printing for statement-expressions. 3729 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3730 const CompoundStmt *Sub = SE->getSubStmt(); 3731 3732 if (Sub->children()) { 3733 OS << "({ ... ; "; 3734 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3735 OS << " })\n"; 3736 return; 3737 } 3738 } 3739 // special printing for comma expressions. 3740 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3741 if (B->getOpcode() == BO_Comma) { 3742 OS << "... , "; 3743 Helper->handledStmt(B->getRHS(),OS); 3744 OS << '\n'; 3745 return; 3746 } 3747 } 3748 } 3749 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3750 3751 if (isa<CXXOperatorCallExpr>(S)) { 3752 OS << " (OperatorCall)"; 3753 } 3754 else if (isa<CXXBindTemporaryExpr>(S)) { 3755 OS << " (BindTemporary)"; 3756 } 3757 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) { 3758 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")"; 3759 } 3760 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) { 3761 OS << " (" << CE->getStmtClassName() << ", " 3762 << CE->getCastKindName() 3763 << ", " << CE->getType().getAsString() 3764 << ")"; 3765 } 3766 3767 // Expressions need a newline. 3768 if (isa<Expr>(S)) 3769 OS << '\n'; 3770 3771 } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) { 3772 const CXXCtorInitializer *I = IE->getInitializer(); 3773 if (I->isBaseInitializer()) 3774 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3775 else OS << I->getAnyMember()->getName(); 3776 3777 OS << "("; 3778 if (Expr *IE = I->getInit()) 3779 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3780 OS << ")"; 3781 3782 if (I->isBaseInitializer()) 3783 OS << " (Base initializer)\n"; 3784 else OS << " (Member initializer)\n"; 3785 3786 } else if (Optional<CFGAutomaticObjDtor> DE = 3787 E.getAs<CFGAutomaticObjDtor>()) { 3788 const VarDecl *VD = DE->getVarDecl(); 3789 Helper->handleDecl(VD, OS); 3790 3791 const Type* T = VD->getType().getTypePtr(); 3792 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3793 T = RT->getPointeeType().getTypePtr(); 3794 T = T->getBaseElementTypeUnsafe(); 3795 3796 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3797 OS << " (Implicit destructor)\n"; 3798 3799 } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) { 3800 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3801 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3802 OS << " (Base object destructor)\n"; 3803 3804 } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) { 3805 const FieldDecl *FD = ME->getFieldDecl(); 3806 const Type *T = FD->getType()->getBaseElementTypeUnsafe(); 3807 OS << "this->" << FD->getName(); 3808 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3809 OS << " (Member object destructor)\n"; 3810 3811 } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) { 3812 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3813 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3814 OS << " (Temporary object destructor)\n"; 3815 } 3816 } 3817 3818 static void print_block(raw_ostream &OS, const CFG* cfg, 3819 const CFGBlock &B, 3820 StmtPrinterHelper* Helper, bool print_edges, 3821 bool ShowColors) { 3822 3823 if (Helper) 3824 Helper->setBlockID(B.getBlockID()); 3825 3826 // Print the header. 3827 if (ShowColors) 3828 OS.changeColor(raw_ostream::YELLOW, true); 3829 3830 OS << "\n [B" << B.getBlockID(); 3831 3832 if (&B == &cfg->getEntry()) 3833 OS << " (ENTRY)]\n"; 3834 else if (&B == &cfg->getExit()) 3835 OS << " (EXIT)]\n"; 3836 else if (&B == cfg->getIndirectGotoBlock()) 3837 OS << " (INDIRECT GOTO DISPATCH)]\n"; 3838 else 3839 OS << "]\n"; 3840 3841 if (ShowColors) 3842 OS.resetColor(); 3843 3844 // Print the label of this block. 3845 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3846 3847 if (print_edges) 3848 OS << " "; 3849 3850 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3851 OS << L->getName(); 3852 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3853 OS << "case "; 3854 C->getLHS()->printPretty(OS, Helper, 3855 PrintingPolicy(Helper->getLangOpts())); 3856 if (C->getRHS()) { 3857 OS << " ... "; 3858 C->getRHS()->printPretty(OS, Helper, 3859 PrintingPolicy(Helper->getLangOpts())); 3860 } 3861 } else if (isa<DefaultStmt>(Label)) 3862 OS << "default"; 3863 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3864 OS << "catch ("; 3865 if (CS->getExceptionDecl()) 3866 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3867 0); 3868 else 3869 OS << "..."; 3870 OS << ")"; 3871 3872 } else 3873 llvm_unreachable("Invalid label statement in CFGBlock."); 3874 3875 OS << ":\n"; 3876 } 3877 3878 // Iterate through the statements in the block and print them. 3879 unsigned j = 1; 3880 3881 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3882 I != E ; ++I, ++j ) { 3883 3884 // Print the statement # in the basic block and the statement itself. 3885 if (print_edges) 3886 OS << " "; 3887 3888 OS << llvm::format("%3d", j) << ": "; 3889 3890 if (Helper) 3891 Helper->setStmtID(j); 3892 3893 print_elem(OS, Helper, *I); 3894 } 3895 3896 // Print the terminator of this block. 3897 if (B.getTerminator()) { 3898 if (ShowColors) 3899 OS.changeColor(raw_ostream::GREEN); 3900 3901 OS << " T: "; 3902 3903 if (Helper) Helper->setBlockID(-1); 3904 3905 PrintingPolicy PP(Helper ? Helper->getLangOpts() : LangOptions()); 3906 CFGBlockTerminatorPrint TPrinter(OS, Helper, PP); 3907 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3908 OS << '\n'; 3909 3910 if (ShowColors) 3911 OS.resetColor(); 3912 } 3913 3914 if (print_edges) { 3915 // Print the predecessors of this block. 3916 if (!B.pred_empty()) { 3917 const raw_ostream::Colors Color = raw_ostream::BLUE; 3918 if (ShowColors) 3919 OS.changeColor(Color); 3920 OS << " Preds " ; 3921 if (ShowColors) 3922 OS.resetColor(); 3923 OS << '(' << B.pred_size() << "):"; 3924 unsigned i = 0; 3925 3926 if (ShowColors) 3927 OS.changeColor(Color); 3928 3929 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3930 I != E; ++I, ++i) { 3931 3932 if (i % 10 == 8) 3933 OS << "\n "; 3934 3935 OS << " B" << (*I)->getBlockID(); 3936 } 3937 3938 if (ShowColors) 3939 OS.resetColor(); 3940 3941 OS << '\n'; 3942 } 3943 3944 // Print the successors of this block. 3945 if (!B.succ_empty()) { 3946 const raw_ostream::Colors Color = raw_ostream::MAGENTA; 3947 if (ShowColors) 3948 OS.changeColor(Color); 3949 OS << " Succs "; 3950 if (ShowColors) 3951 OS.resetColor(); 3952 OS << '(' << B.succ_size() << "):"; 3953 unsigned i = 0; 3954 3955 if (ShowColors) 3956 OS.changeColor(Color); 3957 3958 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3959 I != E; ++I, ++i) { 3960 3961 if (i % 10 == 8) 3962 OS << "\n "; 3963 3964 if (*I) 3965 OS << " B" << (*I)->getBlockID(); 3966 else 3967 OS << " NULL"; 3968 } 3969 3970 if (ShowColors) 3971 OS.resetColor(); 3972 OS << '\n'; 3973 } 3974 } 3975 } 3976 3977 3978 /// dump - A simple pretty printer of a CFG that outputs to stderr. 3979 void CFG::dump(const LangOptions &LO, bool ShowColors) const { 3980 print(llvm::errs(), LO, ShowColors); 3981 } 3982 3983 /// print - A simple pretty printer of a CFG that outputs to an ostream. 3984 void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const { 3985 StmtPrinterHelper Helper(this, LO); 3986 3987 // Print the entry block. 3988 print_block(OS, this, getEntry(), &Helper, true, ShowColors); 3989 3990 // Iterate through the CFGBlocks and print them one by one. 3991 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3992 // Skip the entry block, because we already printed it. 3993 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3994 continue; 3995 3996 print_block(OS, this, **I, &Helper, true, ShowColors); 3997 } 3998 3999 // Print the exit block. 4000 print_block(OS, this, getExit(), &Helper, true, ShowColors); 4001 OS << '\n'; 4002 OS.flush(); 4003 } 4004 4005 /// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 4006 void CFGBlock::dump(const CFG* cfg, const LangOptions &LO, 4007 bool ShowColors) const { 4008 print(llvm::errs(), cfg, LO, ShowColors); 4009 } 4010 4011 /// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 4012 /// Generally this will only be called from CFG::print. 4013 void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 4014 const LangOptions &LO, bool ShowColors) const { 4015 StmtPrinterHelper Helper(cfg, LO); 4016 print_block(OS, cfg, *this, &Helper, true, ShowColors); 4017 OS << '\n'; 4018 } 4019 4020 /// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 4021 void CFGBlock::printTerminator(raw_ostream &OS, 4022 const LangOptions &LO) const { 4023 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 4024 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 4025 } 4026 4027 Stmt *CFGBlock::getTerminatorCondition() { 4028 Stmt *Terminator = this->Terminator; 4029 if (!Terminator) 4030 return NULL; 4031 4032 Expr *E = NULL; 4033 4034 switch (Terminator->getStmtClass()) { 4035 default: 4036 break; 4037 4038 case Stmt::ForStmtClass: 4039 E = cast<ForStmt>(Terminator)->getCond(); 4040 break; 4041 4042 case Stmt::WhileStmtClass: 4043 E = cast<WhileStmt>(Terminator)->getCond(); 4044 break; 4045 4046 case Stmt::DoStmtClass: 4047 E = cast<DoStmt>(Terminator)->getCond(); 4048 break; 4049 4050 case Stmt::IfStmtClass: 4051 E = cast<IfStmt>(Terminator)->getCond(); 4052 break; 4053 4054 case Stmt::ChooseExprClass: 4055 E = cast<ChooseExpr>(Terminator)->getCond(); 4056 break; 4057 4058 case Stmt::IndirectGotoStmtClass: 4059 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 4060 break; 4061 4062 case Stmt::SwitchStmtClass: 4063 E = cast<SwitchStmt>(Terminator)->getCond(); 4064 break; 4065 4066 case Stmt::BinaryConditionalOperatorClass: 4067 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 4068 break; 4069 4070 case Stmt::ConditionalOperatorClass: 4071 E = cast<ConditionalOperator>(Terminator)->getCond(); 4072 break; 4073 4074 case Stmt::BinaryOperatorClass: // '&&' and '||' 4075 E = cast<BinaryOperator>(Terminator)->getLHS(); 4076 break; 4077 4078 case Stmt::ObjCForCollectionStmtClass: 4079 return Terminator; 4080 } 4081 4082 return E ? E->IgnoreParens() : NULL; 4083 } 4084 4085 //===----------------------------------------------------------------------===// 4086 // CFG Graphviz Visualization 4087 //===----------------------------------------------------------------------===// 4088 4089 4090 #ifndef NDEBUG 4091 static StmtPrinterHelper* GraphHelper; 4092 #endif 4093 4094 void CFG::viewCFG(const LangOptions &LO) const { 4095 #ifndef NDEBUG 4096 StmtPrinterHelper H(this, LO); 4097 GraphHelper = &H; 4098 llvm::ViewGraph(this,"CFG"); 4099 GraphHelper = NULL; 4100 #endif 4101 } 4102 4103 namespace llvm { 4104 template<> 4105 struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 4106 4107 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 4108 4109 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 4110 4111 #ifndef NDEBUG 4112 std::string OutSStr; 4113 llvm::raw_string_ostream Out(OutSStr); 4114 print_block(Out,Graph, *Node, GraphHelper, false, false); 4115 std::string& OutStr = Out.str(); 4116 4117 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 4118 4119 // Process string output to make it nicer... 4120 for (unsigned i = 0; i != OutStr.length(); ++i) 4121 if (OutStr[i] == '\n') { // Left justify 4122 OutStr[i] = '\\'; 4123 OutStr.insert(OutStr.begin()+i+1, 'l'); 4124 } 4125 4126 return OutStr; 4127 #else 4128 return ""; 4129 #endif 4130 } 4131 }; 4132 } // end namespace llvm 4133