CFG.cpp revision 6955da2cad4bce19c541ddb85a6d965d77a1a4ab
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 "llvm/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "clang/AST/CharUnits.h" 21#include "llvm/Support/GraphWriter.h" 22#include "llvm/Support/Allocator.h" 23#include "llvm/Support/Format.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/OwningPtr.h" 27 28using namespace clang; 29 30namespace { 31 32static SourceLocation GetEndLoc(Decl *D) { 33 if (VarDecl *VD = dyn_cast<VarDecl>(D)) 34 if (Expr *Ex = VD->getInit()) 35 return Ex->getSourceRange().getEnd(); 36 return D->getLocation(); 37} 38 39class CFGBuilder; 40 41/// The CFG builder uses a recursive algorithm to build the CFG. When 42/// we process an expression, sometimes we know that we must add the 43/// subexpressions as block-level expressions. For example: 44/// 45/// exp1 || exp2 46/// 47/// When processing the '||' expression, we know that exp1 and exp2 48/// need to be added as block-level expressions, even though they 49/// might not normally need to be. AddStmtChoice records this 50/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 51/// the builder has an option not to add a subexpression as a 52/// block-level expression. 53/// 54class AddStmtChoice { 55public: 56 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 57 58 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 59 60 bool alwaysAdd(CFGBuilder &builder, 61 const Stmt *stmt) const; 62 63 /// Return a copy of this object, except with the 'always-add' bit 64 /// set as specified. 65 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 66 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 67 } 68 69private: 70 Kind kind; 71}; 72 73/// LocalScope - Node in tree of local scopes created for C++ implicit 74/// destructor calls generation. It contains list of automatic variables 75/// declared in the scope and link to position in previous scope this scope 76/// began in. 77/// 78/// The process of creating local scopes is as follows: 79/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 80/// - Before processing statements in scope (e.g. CompoundStmt) create 81/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 82/// and set CFGBuilder::ScopePos to the end of new scope, 83/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 84/// at this VarDecl, 85/// - For every normal (without jump) end of scope add to CFGBlock destructors 86/// for objects in the current scope, 87/// - For every jump add to CFGBlock destructors for objects 88/// between CFGBuilder::ScopePos and local scope position saved for jump 89/// target. Thanks to C++ restrictions on goto jumps we can be sure that 90/// jump target position will be on the path to root from CFGBuilder::ScopePos 91/// (adding any variable that doesn't need constructor to be called to 92/// LocalScope can break this assumption), 93/// 94class LocalScope { 95public: 96 typedef BumpVector<VarDecl*> AutomaticVarsTy; 97 98 /// const_iterator - Iterates local scope backwards and jumps to previous 99 /// scope on reaching the beginning of currently iterated scope. 100 class const_iterator { 101 const LocalScope* Scope; 102 103 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 104 /// Invalid iterator (with null Scope) has VarIter equal to 0. 105 unsigned VarIter; 106 107 public: 108 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 109 /// Incrementing invalid iterator is allowed and will result in invalid 110 /// iterator. 111 const_iterator() 112 : Scope(NULL), VarIter(0) {} 113 114 /// Create valid iterator. In case when S.Prev is an invalid iterator and 115 /// I is equal to 0, this will create invalid iterator. 116 const_iterator(const LocalScope& S, unsigned I) 117 : Scope(&S), VarIter(I) { 118 // Iterator to "end" of scope is not allowed. Handle it by going up 119 // in scopes tree possibly up to invalid iterator in the root. 120 if (VarIter == 0 && Scope) 121 *this = Scope->Prev; 122 } 123 124 VarDecl *const* operator->() const { 125 assert (Scope && "Dereferencing invalid iterator is not allowed"); 126 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 127 return &Scope->Vars[VarIter - 1]; 128 } 129 VarDecl *operator*() const { 130 return *this->operator->(); 131 } 132 133 const_iterator &operator++() { 134 if (!Scope) 135 return *this; 136 137 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 138 --VarIter; 139 if (VarIter == 0) 140 *this = Scope->Prev; 141 return *this; 142 } 143 const_iterator operator++(int) { 144 const_iterator P = *this; 145 ++*this; 146 return P; 147 } 148 149 bool operator==(const const_iterator &rhs) const { 150 return Scope == rhs.Scope && VarIter == rhs.VarIter; 151 } 152 bool operator!=(const const_iterator &rhs) const { 153 return !(*this == rhs); 154 } 155 156 operator bool() const { 157 return *this != const_iterator(); 158 } 159 160 int distance(const_iterator L); 161 }; 162 163 friend class const_iterator; 164 165private: 166 BumpVectorContext ctx; 167 168 /// Automatic variables in order of declaration. 169 AutomaticVarsTy Vars; 170 /// Iterator to variable in previous scope that was declared just before 171 /// begin of this scope. 172 const_iterator Prev; 173 174public: 175 /// Constructs empty scope linked to previous scope in specified place. 176 LocalScope(BumpVectorContext &ctx, const_iterator P) 177 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 178 179 /// Begin of scope in direction of CFG building (backwards). 180 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 181 182 void addVar(VarDecl *VD) { 183 Vars.push_back(VD, ctx); 184 } 185}; 186 187/// distance - Calculates distance from this to L. L must be reachable from this 188/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 189/// number of scopes between this and L. 190int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 191 int D = 0; 192 const_iterator F = *this; 193 while (F.Scope != L.Scope) { 194 assert (F != const_iterator() 195 && "L iterator is not reachable from F iterator."); 196 D += F.VarIter; 197 F = F.Scope->Prev; 198 } 199 D += F.VarIter - L.VarIter; 200 return D; 201} 202 203/// BlockScopePosPair - Structure for specifying position in CFG during its 204/// build process. It consists of CFGBlock that specifies position in CFG graph 205/// and LocalScope::const_iterator that specifies position in LocalScope graph. 206struct BlockScopePosPair { 207 BlockScopePosPair() : block(0) {} 208 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos) 209 : block(b), scopePosition(scopePos) {} 210 211 CFGBlock *block; 212 LocalScope::const_iterator scopePosition; 213}; 214 215/// TryResult - a class representing a variant over the values 216/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 217/// and is used by the CFGBuilder to decide if a branch condition 218/// can be decided up front during CFG construction. 219class TryResult { 220 int X; 221public: 222 TryResult(bool b) : X(b ? 1 : 0) {} 223 TryResult() : X(-1) {} 224 225 bool isTrue() const { return X == 1; } 226 bool isFalse() const { return X == 0; } 227 bool isKnown() const { return X >= 0; } 228 void negate() { 229 assert(isKnown()); 230 X ^= 0x1; 231 } 232}; 233 234/// CFGBuilder - This class implements CFG construction from an AST. 235/// The builder is stateful: an instance of the builder should be used to only 236/// construct a single CFG. 237/// 238/// Example usage: 239/// 240/// CFGBuilder builder; 241/// CFG* cfg = builder.BuildAST(stmt1); 242/// 243/// CFG construction is done via a recursive walk of an AST. We actually parse 244/// the AST in reverse order so that the successor of a basic block is 245/// constructed prior to its predecessor. This allows us to nicely capture 246/// implicit fall-throughs without extra basic blocks. 247/// 248class CFGBuilder { 249 typedef BlockScopePosPair JumpTarget; 250 typedef BlockScopePosPair JumpSource; 251 252 ASTContext *Context; 253 OwningPtr<CFG> cfg; 254 255 CFGBlock *Block; 256 CFGBlock *Succ; 257 JumpTarget ContinueJumpTarget; 258 JumpTarget BreakJumpTarget; 259 CFGBlock *SwitchTerminatedBlock; 260 CFGBlock *DefaultCaseBlock; 261 CFGBlock *TryTerminatedBlock; 262 263 // Current position in local scope. 264 LocalScope::const_iterator ScopePos; 265 266 // LabelMap records the mapping from Label expressions to their jump targets. 267 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 268 LabelMapTy LabelMap; 269 270 // A list of blocks that end with a "goto" that must be backpatched to their 271 // resolved targets upon completion of CFG construction. 272 typedef std::vector<JumpSource> BackpatchBlocksTy; 273 BackpatchBlocksTy BackpatchBlocks; 274 275 // A list of labels whose address has been taken (for indirect gotos). 276 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 277 LabelSetTy AddressTakenLabels; 278 279 bool badCFG; 280 const CFG::BuildOptions &BuildOpts; 281 282 // State to track for building switch statements. 283 bool switchExclusivelyCovered; 284 Expr::EvalResult *switchCond; 285 286 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 287 const Stmt *lastLookup; 288 289 // Caches boolean evaluations of expressions to avoid multiple re-evaluations 290 // during construction of branches for chained logical operators. 291 typedef llvm::DenseMap<Expr *, TryResult> CachedBoolEvalsTy; 292 CachedBoolEvalsTy CachedBoolEvals; 293 294public: 295 explicit CFGBuilder(ASTContext *astContext, 296 const CFG::BuildOptions &buildOpts) 297 : Context(astContext), cfg(new CFG()), // crew a new CFG 298 Block(NULL), Succ(NULL), 299 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 300 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 301 switchExclusivelyCovered(false), switchCond(0), 302 cachedEntry(0), lastLookup(0) {} 303 304 // buildCFG - Used by external clients to construct the CFG. 305 CFG* buildCFG(const Decl *D, Stmt *Statement); 306 307 bool alwaysAdd(const Stmt *stmt); 308 309private: 310 // Visitors to walk an AST and construct the CFG. 311 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 312 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 313 CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc); 314 CFGBlock *VisitBreakStmt(BreakStmt *B); 315 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 316 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 317 AddStmtChoice asc); 318 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 319 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 320 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 321 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 322 AddStmtChoice asc); 323 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 324 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 325 AddStmtChoice asc); 326 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 327 AddStmtChoice asc); 328 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 329 CFGBlock *VisitCaseStmt(CaseStmt *C); 330 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 331 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 332 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 333 AddStmtChoice asc); 334 CFGBlock *VisitContinueStmt(ContinueStmt *C); 335 CFGBlock *VisitDeclStmt(DeclStmt *DS); 336 CFGBlock *VisitDeclSubExpr(DeclStmt *DS); 337 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 338 CFGBlock *VisitDoStmt(DoStmt *D); 339 CFGBlock *VisitForStmt(ForStmt *F); 340 CFGBlock *VisitGotoStmt(GotoStmt *G); 341 CFGBlock *VisitIfStmt(IfStmt *I); 342 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 343 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 344 CFGBlock *VisitLabelStmt(LabelStmt *L); 345 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 346 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 347 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S); 348 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 349 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 350 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 351 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 352 CFGBlock *VisitReturnStmt(ReturnStmt *R); 353 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E); 354 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 355 AddStmtChoice asc); 356 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 357 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 358 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 359 CFGBlock *VisitWhileStmt(WhileStmt *W); 360 361 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 362 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 363 CFGBlock *VisitChildren(Stmt *S); 364 365 // Visitors to walk an AST and generate destructors of temporaries in 366 // full expression. 367 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 368 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 369 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 370 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 371 bool BindToTemporary); 372 CFGBlock * 373 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 374 bool BindToTemporary); 375 376 // NYS == Not Yet Supported 377 CFGBlock *NYS() { 378 badCFG = true; 379 return Block; 380 } 381 382 void autoCreateBlock() { if (!Block) Block = createBlock(); } 383 CFGBlock *createBlock(bool add_successor = true); 384 CFGBlock *createNoReturnBlock(); 385 386 CFGBlock *addStmt(Stmt *S) { 387 return Visit(S, AddStmtChoice::AlwaysAdd); 388 } 389 CFGBlock *addInitializer(CXXCtorInitializer *I); 390 void addAutomaticObjDtors(LocalScope::const_iterator B, 391 LocalScope::const_iterator E, Stmt *S); 392 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 393 394 // Local scopes creation. 395 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 396 397 void addLocalScopeForStmt(Stmt *S); 398 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 399 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 400 401 void addLocalScopeAndDtors(Stmt *S); 402 403 // Interface to CFGBlock - adding CFGElements. 404 void appendStmt(CFGBlock *B, const Stmt *S) { 405 if (alwaysAdd(S) && cachedEntry) 406 cachedEntry->second = B; 407 408 // All block-level expressions should have already been IgnoreParens()ed. 409 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 410 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 411 } 412 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 413 B->appendInitializer(I, cfg->getBumpVectorContext()); 414 } 415 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 416 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 417 } 418 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 419 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 420 } 421 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 422 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 423 } 424 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 425 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 426 } 427 428 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 429 LocalScope::const_iterator B, LocalScope::const_iterator E); 430 431 void addSuccessor(CFGBlock *B, CFGBlock *S) { 432 B->addSuccessor(S, cfg->getBumpVectorContext()); 433 } 434 435 /// Try and evaluate an expression to an integer constant. 436 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 437 if (!BuildOpts.PruneTriviallyFalseEdges) 438 return false; 439 return !S->isTypeDependent() && 440 !S->isValueDependent() && 441 S->EvaluateAsRValue(outResult, *Context); 442 } 443 444 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 445 /// if we can evaluate to a known value, otherwise return -1. 446 TryResult tryEvaluateBool(Expr *S) { 447 if (!BuildOpts.PruneTriviallyFalseEdges || 448 S->isTypeDependent() || S->isValueDependent()) 449 return TryResult(); 450 451 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) { 452 if (Bop->isLogicalOp()) { 453 // Check the cache first. 454 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S); 455 if (I != CachedBoolEvals.end()) 456 return I->second; // already in map; 457 458 // Retrieve result at first, or the map might be updated. 459 TryResult Result = evaluateAsBooleanConditionNoCache(S); 460 CachedBoolEvals[S] = Result; // update or insert 461 return Result; 462 } 463 } 464 465 return evaluateAsBooleanConditionNoCache(S); 466 } 467 468 /// \brief Evaluate as boolean \param E without using the cache. 469 TryResult evaluateAsBooleanConditionNoCache(Expr *E) { 470 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) { 471 if (Bop->isLogicalOp()) { 472 TryResult LHS = tryEvaluateBool(Bop->getLHS()); 473 if (LHS.isKnown()) { 474 // We were able to evaluate the LHS, see if we can get away with not 475 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1 476 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr)) 477 return LHS.isTrue(); 478 479 TryResult RHS = tryEvaluateBool(Bop->getRHS()); 480 if (RHS.isKnown()) { 481 if (Bop->getOpcode() == BO_LOr) 482 return LHS.isTrue() || RHS.isTrue(); 483 else 484 return LHS.isTrue() && RHS.isTrue(); 485 } 486 } else { 487 TryResult RHS = tryEvaluateBool(Bop->getRHS()); 488 if (RHS.isKnown()) { 489 // We can't evaluate the LHS; however, sometimes the result 490 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 491 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr)) 492 return RHS.isTrue(); 493 } 494 } 495 496 return TryResult(); 497 } 498 } 499 500 bool Result; 501 if (E->EvaluateAsBooleanCondition(Result, *Context)) 502 return Result; 503 504 return TryResult(); 505 } 506 507}; 508 509inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 510 const Stmt *stmt) const { 511 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 512} 513 514bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 515 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 516 517 if (!BuildOpts.forcedBlkExprs) 518 return shouldAdd; 519 520 if (lastLookup == stmt) { 521 if (cachedEntry) { 522 assert(cachedEntry->first == stmt); 523 return true; 524 } 525 return shouldAdd; 526 } 527 528 lastLookup = stmt; 529 530 // Perform the lookup! 531 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 532 533 if (!fb) { 534 // No need to update 'cachedEntry', since it will always be null. 535 assert(cachedEntry == 0); 536 return shouldAdd; 537 } 538 539 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 540 if (itr == fb->end()) { 541 cachedEntry = 0; 542 return shouldAdd; 543 } 544 545 cachedEntry = &*itr; 546 return true; 547} 548 549// FIXME: Add support for dependent-sized array types in C++? 550// Does it even make sense to build a CFG for an uninstantiated template? 551static const VariableArrayType *FindVA(const Type *t) { 552 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 553 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 554 if (vat->getSizeExpr()) 555 return vat; 556 557 t = vt->getElementType().getTypePtr(); 558 } 559 560 return 0; 561} 562 563/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 564/// arbitrary statement. Examples include a single expression or a function 565/// body (compound statement). The ownership of the returned CFG is 566/// transferred to the caller. If CFG construction fails, this method returns 567/// NULL. 568CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 569 assert(cfg.get()); 570 if (!Statement) 571 return NULL; 572 573 // Create an empty block that will serve as the exit block for the CFG. Since 574 // this is the first block added to the CFG, it will be implicitly registered 575 // as the exit block. 576 Succ = createBlock(); 577 assert(Succ == &cfg->getExit()); 578 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 579 580 if (BuildOpts.AddImplicitDtors) 581 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 582 addImplicitDtorsForDestructor(DD); 583 584 // Visit the statements and create the CFG. 585 CFGBlock *B = addStmt(Statement); 586 587 if (badCFG) 588 return NULL; 589 590 // For C++ constructor add initializers to CFG. 591 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 592 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 593 E = CD->init_rend(); I != E; ++I) { 594 B = addInitializer(*I); 595 if (badCFG) 596 return NULL; 597 } 598 } 599 600 if (B) 601 Succ = B; 602 603 // Backpatch the gotos whose label -> block mappings we didn't know when we 604 // encountered them. 605 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 606 E = BackpatchBlocks.end(); I != E; ++I ) { 607 608 CFGBlock *B = I->block; 609 GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 610 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 611 612 // If there is no target for the goto, then we are looking at an 613 // incomplete AST. Handle this by not registering a successor. 614 if (LI == LabelMap.end()) continue; 615 616 JumpTarget JT = LI->second; 617 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 618 JT.scopePosition); 619 addSuccessor(B, JT.block); 620 } 621 622 // Add successors to the Indirect Goto Dispatch block (if we have one). 623 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 624 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 625 E = AddressTakenLabels.end(); I != E; ++I ) { 626 627 // Lookup the target block. 628 LabelMapTy::iterator LI = LabelMap.find(*I); 629 630 // If there is no target block that contains label, then we are looking 631 // at an incomplete AST. Handle this by not registering a successor. 632 if (LI == LabelMap.end()) continue; 633 634 addSuccessor(B, LI->second.block); 635 } 636 637 // Create an empty entry block that has no predecessors. 638 cfg->setEntry(createBlock()); 639 640 return cfg.take(); 641} 642 643/// createBlock - Used to lazily create blocks that are connected 644/// to the current (global) succcessor. 645CFGBlock *CFGBuilder::createBlock(bool add_successor) { 646 CFGBlock *B = cfg->createBlock(); 647 if (add_successor && Succ) 648 addSuccessor(B, Succ); 649 return B; 650} 651 652/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the 653/// CFG. It is *not* connected to the current (global) successor, and instead 654/// directly tied to the exit block in order to be reachable. 655CFGBlock *CFGBuilder::createNoReturnBlock() { 656 CFGBlock *B = createBlock(false); 657 B->setHasNoReturnElement(); 658 addSuccessor(B, &cfg->getExit()); 659 return B; 660} 661 662/// addInitializer - Add C++ base or member initializer element to CFG. 663CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 664 if (!BuildOpts.AddInitializers) 665 return Block; 666 667 bool IsReference = false; 668 bool HasTemporaries = false; 669 670 // Destructors of temporaries in initialization expression should be called 671 // after initialization finishes. 672 Expr *Init = I->getInit(); 673 if (Init) { 674 if (FieldDecl *FD = I->getAnyMember()) 675 IsReference = FD->getType()->isReferenceType(); 676 HasTemporaries = isa<ExprWithCleanups>(Init); 677 678 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 679 // Generate destructors for temporaries in initialization expression. 680 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 681 IsReference); 682 } 683 } 684 685 autoCreateBlock(); 686 appendInitializer(Block, I); 687 688 if (Init) { 689 if (HasTemporaries) { 690 // For expression with temporaries go directly to subexpression to omit 691 // generating destructors for the second time. 692 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 693 } 694 return Visit(Init); 695 } 696 697 return Block; 698} 699 700/// \brief Retrieve the type of the temporary object whose lifetime was 701/// extended by a local reference with the given initializer. 702static QualType getReferenceInitTemporaryType(ASTContext &Context, 703 const Expr *Init) { 704 while (true) { 705 // Skip parentheses. 706 Init = Init->IgnoreParens(); 707 708 // Skip through cleanups. 709 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) { 710 Init = EWC->getSubExpr(); 711 continue; 712 } 713 714 // Skip through the temporary-materialization expression. 715 if (const MaterializeTemporaryExpr *MTE 716 = dyn_cast<MaterializeTemporaryExpr>(Init)) { 717 Init = MTE->GetTemporaryExpr(); 718 continue; 719 } 720 721 // Skip derived-to-base and no-op casts. 722 if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) { 723 if ((CE->getCastKind() == CK_DerivedToBase || 724 CE->getCastKind() == CK_UncheckedDerivedToBase || 725 CE->getCastKind() == CK_NoOp) && 726 Init->getType()->isRecordType()) { 727 Init = CE->getSubExpr(); 728 continue; 729 } 730 } 731 732 // Skip member accesses into rvalues. 733 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) { 734 if (!ME->isArrow() && ME->getBase()->isRValue()) { 735 Init = ME->getBase(); 736 continue; 737 } 738 } 739 740 break; 741 } 742 743 return Init->getType(); 744} 745 746/// addAutomaticObjDtors - Add to current block automatic objects destructors 747/// for objects in range of local scope positions. Use S as trigger statement 748/// for destructors. 749void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 750 LocalScope::const_iterator E, Stmt *S) { 751 if (!BuildOpts.AddImplicitDtors) 752 return; 753 754 if (B == E) 755 return; 756 757 // We need to append the destructors in reverse order, but any one of them 758 // may be a no-return destructor which changes the CFG. As a result, buffer 759 // this sequence up and replay them in reverse order when appending onto the 760 // CFGBlock(s). 761 SmallVector<VarDecl*, 10> Decls; 762 Decls.reserve(B.distance(E)); 763 for (LocalScope::const_iterator I = B; I != E; ++I) 764 Decls.push_back(*I); 765 766 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 767 E = Decls.rend(); 768 I != E; ++I) { 769 // If this destructor is marked as a no-return destructor, we need to 770 // create a new block for the destructor which does not have as a successor 771 // anything built thus far: control won't flow out of this block. 772 QualType Ty; 773 if ((*I)->getType()->isReferenceType()) { 774 Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit()); 775 } else { 776 Ty = Context->getBaseElementType((*I)->getType()); 777 } 778 779 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 780 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 781 Block = createNoReturnBlock(); 782 else 783 autoCreateBlock(); 784 785 appendAutomaticObjDtor(Block, *I, S); 786 } 787} 788 789/// addImplicitDtorsForDestructor - Add implicit destructors generated for 790/// base and member objects in destructor. 791void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 792 assert (BuildOpts.AddImplicitDtors 793 && "Can be called only when dtors should be added"); 794 const CXXRecordDecl *RD = DD->getParent(); 795 796 // At the end destroy virtual base objects. 797 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 798 VE = RD->vbases_end(); VI != VE; ++VI) { 799 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 800 if (!CD->hasTrivialDestructor()) { 801 autoCreateBlock(); 802 appendBaseDtor(Block, VI); 803 } 804 } 805 806 // Before virtual bases destroy direct base objects. 807 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 808 BE = RD->bases_end(); BI != BE; ++BI) { 809 if (!BI->isVirtual()) { 810 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 811 if (!CD->hasTrivialDestructor()) { 812 autoCreateBlock(); 813 appendBaseDtor(Block, BI); 814 } 815 } 816 } 817 818 // First destroy member objects. 819 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 820 FE = RD->field_end(); FI != FE; ++FI) { 821 // Check for constant size array. Set type to array element type. 822 QualType QT = FI->getType(); 823 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 824 if (AT->getSize() == 0) 825 continue; 826 QT = AT->getElementType(); 827 } 828 829 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 830 if (!CD->hasTrivialDestructor()) { 831 autoCreateBlock(); 832 appendMemberDtor(Block, *FI); 833 } 834 } 835} 836 837/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 838/// way return valid LocalScope object. 839LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 840 if (!Scope) { 841 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 842 Scope = alloc.Allocate<LocalScope>(); 843 BumpVectorContext ctx(alloc); 844 new (Scope) LocalScope(ctx, ScopePos); 845 } 846 return Scope; 847} 848 849/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 850/// that should create implicit scope (e.g. if/else substatements). 851void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 852 if (!BuildOpts.AddImplicitDtors) 853 return; 854 855 LocalScope *Scope = 0; 856 857 // For compound statement we will be creating explicit scope. 858 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 859 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 860 ; BI != BE; ++BI) { 861 Stmt *SI = (*BI)->stripLabelLikeStatements(); 862 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 863 Scope = addLocalScopeForDeclStmt(DS, Scope); 864 } 865 return; 866 } 867 868 // For any other statement scope will be implicit and as such will be 869 // interesting only for DeclStmt. 870 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 871 addLocalScopeForDeclStmt(DS); 872} 873 874/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 875/// reuse Scope if not NULL. 876LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 877 LocalScope* Scope) { 878 if (!BuildOpts.AddImplicitDtors) 879 return Scope; 880 881 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 882 ; DI != DE; ++DI) { 883 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 884 Scope = addLocalScopeForVarDecl(VD, Scope); 885 } 886 return Scope; 887} 888 889/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 890/// create add scope for automatic objects and temporary objects bound to 891/// const reference. Will reuse Scope if not NULL. 892LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 893 LocalScope* Scope) { 894 if (!BuildOpts.AddImplicitDtors) 895 return Scope; 896 897 // Check if variable is local. 898 switch (VD->getStorageClass()) { 899 case SC_None: 900 case SC_Auto: 901 case SC_Register: 902 break; 903 default: return Scope; 904 } 905 906 // Check for const references bound to temporary. Set type to pointee. 907 QualType QT = VD->getType(); 908 if (QT.getTypePtr()->isReferenceType()) { 909 if (!VD->extendsLifetimeOfTemporary()) 910 return Scope; 911 912 QT = getReferenceInitTemporaryType(*Context, VD->getInit()); 913 } 914 915 // Check for constant size array. Set type to array element type. 916 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 917 if (AT->getSize() == 0) 918 return Scope; 919 QT = AT->getElementType(); 920 } 921 922 // Check if type is a C++ class with non-trivial destructor. 923 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 924 if (!CD->hasTrivialDestructor()) { 925 // Add the variable to scope 926 Scope = createOrReuseLocalScope(Scope); 927 Scope->addVar(VD); 928 ScopePos = Scope->begin(); 929 } 930 return Scope; 931} 932 933/// addLocalScopeAndDtors - For given statement add local scope for it and 934/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 935void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 936 if (!BuildOpts.AddImplicitDtors) 937 return; 938 939 LocalScope::const_iterator scopeBeginPos = ScopePos; 940 addLocalScopeForStmt(S); 941 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 942} 943 944/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 945/// variables with automatic storage duration to CFGBlock's elements vector. 946/// Elements will be prepended to physical beginning of the vector which 947/// happens to be logical end. Use blocks terminator as statement that specifies 948/// destructors call site. 949/// FIXME: This mechanism for adding automatic destructors doesn't handle 950/// no-return destructors properly. 951void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 952 LocalScope::const_iterator B, LocalScope::const_iterator E) { 953 BumpVectorContext &C = cfg->getBumpVectorContext(); 954 CFGBlock::iterator InsertPos 955 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 956 for (LocalScope::const_iterator I = B; I != E; ++I) 957 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 958 Blk->getTerminator()); 959} 960 961/// Visit - Walk the subtree of a statement and add extra 962/// blocks for ternary operators, &&, and ||. We also process "," and 963/// DeclStmts (which may contain nested control-flow). 964CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 965 if (!S) { 966 badCFG = true; 967 return 0; 968 } 969 970 if (Expr *E = dyn_cast<Expr>(S)) 971 S = E->IgnoreParens(); 972 973 switch (S->getStmtClass()) { 974 default: 975 return VisitStmt(S, asc); 976 977 case Stmt::AddrLabelExprClass: 978 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 979 980 case Stmt::BinaryConditionalOperatorClass: 981 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 982 983 case Stmt::BinaryOperatorClass: 984 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 985 986 case Stmt::BlockExprClass: 987 return VisitBlockExpr(cast<BlockExpr>(S), asc); 988 989 case Stmt::BreakStmtClass: 990 return VisitBreakStmt(cast<BreakStmt>(S)); 991 992 case Stmt::CallExprClass: 993 case Stmt::CXXOperatorCallExprClass: 994 case Stmt::CXXMemberCallExprClass: 995 case Stmt::UserDefinedLiteralClass: 996 return VisitCallExpr(cast<CallExpr>(S), asc); 997 998 case Stmt::CaseStmtClass: 999 return VisitCaseStmt(cast<CaseStmt>(S)); 1000 1001 case Stmt::ChooseExprClass: 1002 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 1003 1004 case Stmt::CompoundStmtClass: 1005 return VisitCompoundStmt(cast<CompoundStmt>(S)); 1006 1007 case Stmt::ConditionalOperatorClass: 1008 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 1009 1010 case Stmt::ContinueStmtClass: 1011 return VisitContinueStmt(cast<ContinueStmt>(S)); 1012 1013 case Stmt::CXXCatchStmtClass: 1014 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 1015 1016 case Stmt::ExprWithCleanupsClass: 1017 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 1018 1019 case Stmt::CXXBindTemporaryExprClass: 1020 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 1021 1022 case Stmt::CXXConstructExprClass: 1023 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 1024 1025 case Stmt::CXXFunctionalCastExprClass: 1026 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 1027 1028 case Stmt::CXXTemporaryObjectExprClass: 1029 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 1030 1031 case Stmt::CXXThrowExprClass: 1032 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 1033 1034 case Stmt::CXXTryStmtClass: 1035 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 1036 1037 case Stmt::CXXForRangeStmtClass: 1038 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 1039 1040 case Stmt::DeclStmtClass: 1041 return VisitDeclStmt(cast<DeclStmt>(S)); 1042 1043 case Stmt::DefaultStmtClass: 1044 return VisitDefaultStmt(cast<DefaultStmt>(S)); 1045 1046 case Stmt::DoStmtClass: 1047 return VisitDoStmt(cast<DoStmt>(S)); 1048 1049 case Stmt::ForStmtClass: 1050 return VisitForStmt(cast<ForStmt>(S)); 1051 1052 case Stmt::GotoStmtClass: 1053 return VisitGotoStmt(cast<GotoStmt>(S)); 1054 1055 case Stmt::IfStmtClass: 1056 return VisitIfStmt(cast<IfStmt>(S)); 1057 1058 case Stmt::ImplicitCastExprClass: 1059 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 1060 1061 case Stmt::IndirectGotoStmtClass: 1062 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 1063 1064 case Stmt::LabelStmtClass: 1065 return VisitLabelStmt(cast<LabelStmt>(S)); 1066 1067 case Stmt::MemberExprClass: 1068 return VisitMemberExpr(cast<MemberExpr>(S), asc); 1069 1070 case Stmt::NullStmtClass: 1071 return Block; 1072 1073 case Stmt::ObjCAtCatchStmtClass: 1074 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 1075 1076 case Stmt::ObjCAutoreleasePoolStmtClass: 1077 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S)); 1078 1079 case Stmt::ObjCAtSynchronizedStmtClass: 1080 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 1081 1082 case Stmt::ObjCAtThrowStmtClass: 1083 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 1084 1085 case Stmt::ObjCAtTryStmtClass: 1086 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 1087 1088 case Stmt::ObjCForCollectionStmtClass: 1089 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 1090 1091 case Stmt::OpaqueValueExprClass: 1092 return Block; 1093 1094 case Stmt::PseudoObjectExprClass: 1095 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S)); 1096 1097 case Stmt::ReturnStmtClass: 1098 return VisitReturnStmt(cast<ReturnStmt>(S)); 1099 1100 case Stmt::UnaryExprOrTypeTraitExprClass: 1101 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 1102 asc); 1103 1104 case Stmt::StmtExprClass: 1105 return VisitStmtExpr(cast<StmtExpr>(S), asc); 1106 1107 case Stmt::SwitchStmtClass: 1108 return VisitSwitchStmt(cast<SwitchStmt>(S)); 1109 1110 case Stmt::UnaryOperatorClass: 1111 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 1112 1113 case Stmt::WhileStmtClass: 1114 return VisitWhileStmt(cast<WhileStmt>(S)); 1115 } 1116} 1117 1118CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1119 if (asc.alwaysAdd(*this, S)) { 1120 autoCreateBlock(); 1121 appendStmt(Block, S); 1122 } 1123 1124 return VisitChildren(S); 1125} 1126 1127/// VisitChildren - Visit the children of a Stmt. 1128CFGBlock *CFGBuilder::VisitChildren(Stmt *Terminator) { 1129 CFGBlock *lastBlock = Block; 1130 for (Stmt::child_range I = Terminator->children(); I; ++I) 1131 if (Stmt *child = *I) 1132 if (CFGBlock *b = Visit(child)) 1133 lastBlock = b; 1134 1135 return lastBlock; 1136} 1137 1138CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1139 AddStmtChoice asc) { 1140 AddressTakenLabels.insert(A->getLabel()); 1141 1142 if (asc.alwaysAdd(*this, A)) { 1143 autoCreateBlock(); 1144 appendStmt(Block, A); 1145 } 1146 1147 return Block; 1148} 1149 1150CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1151 AddStmtChoice asc) { 1152 if (asc.alwaysAdd(*this, U)) { 1153 autoCreateBlock(); 1154 appendStmt(Block, U); 1155 } 1156 1157 return Visit(U->getSubExpr(), AddStmtChoice()); 1158} 1159 1160CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1161 AddStmtChoice asc) { 1162 if (B->isLogicalOp()) { // && or || 1163 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1164 appendStmt(ConfluenceBlock, B); 1165 1166 if (badCFG) 1167 return 0; 1168 1169 // create the block evaluating the LHS 1170 CFGBlock *LHSBlock = createBlock(false); 1171 LHSBlock->setTerminator(B); 1172 1173 // create the block evaluating the RHS 1174 Succ = ConfluenceBlock; 1175 Block = NULL; 1176 CFGBlock *RHSBlock = addStmt(B->getRHS()); 1177 1178 if (RHSBlock) { 1179 if (badCFG) 1180 return 0; 1181 } else { 1182 // Create an empty block for cases where the RHS doesn't require 1183 // any explicit statements in the CFG. 1184 RHSBlock = createBlock(); 1185 } 1186 1187 // Generate the blocks for evaluating the LHS. 1188 Block = LHSBlock; 1189 CFGBlock *EntryLHSBlock = addStmt(B->getLHS()); 1190 1191 // See if this is a known constant. 1192 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1193 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1194 KnownVal.negate(); 1195 1196 // Now link the LHSBlock with RHSBlock. 1197 if (B->getOpcode() == BO_LOr) { 1198 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1199 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1200 } else { 1201 assert(B->getOpcode() == BO_LAnd); 1202 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1203 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1204 } 1205 1206 return EntryLHSBlock; 1207 } 1208 1209 if (B->getOpcode() == BO_Comma) { // , 1210 autoCreateBlock(); 1211 appendStmt(Block, B); 1212 addStmt(B->getRHS()); 1213 return addStmt(B->getLHS()); 1214 } 1215 1216 if (B->isAssignmentOp()) { 1217 if (asc.alwaysAdd(*this, B)) { 1218 autoCreateBlock(); 1219 appendStmt(Block, B); 1220 } 1221 Visit(B->getLHS()); 1222 return Visit(B->getRHS()); 1223 } 1224 1225 if (asc.alwaysAdd(*this, B)) { 1226 autoCreateBlock(); 1227 appendStmt(Block, B); 1228 } 1229 1230 CFGBlock *RBlock = Visit(B->getRHS()); 1231 CFGBlock *LBlock = Visit(B->getLHS()); 1232 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1233 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1234 // return RBlock. Otherwise we'll incorrectly return NULL. 1235 return (LBlock ? LBlock : RBlock); 1236} 1237 1238CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1239 if (asc.alwaysAdd(*this, E)) { 1240 autoCreateBlock(); 1241 appendStmt(Block, E); 1242 } 1243 return Block; 1244} 1245 1246CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1247 // "break" is a control-flow statement. Thus we stop processing the current 1248 // block. 1249 if (badCFG) 1250 return 0; 1251 1252 // Now create a new block that ends with the break statement. 1253 Block = createBlock(false); 1254 Block->setTerminator(B); 1255 1256 // If there is no target for the break, then we are looking at an incomplete 1257 // AST. This means that the CFG cannot be constructed. 1258 if (BreakJumpTarget.block) { 1259 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1260 addSuccessor(Block, BreakJumpTarget.block); 1261 } else 1262 badCFG = true; 1263 1264 1265 return Block; 1266} 1267 1268static bool CanThrow(Expr *E, ASTContext &Ctx) { 1269 QualType Ty = E->getType(); 1270 if (Ty->isFunctionPointerType()) 1271 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1272 else if (Ty->isBlockPointerType()) 1273 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1274 1275 const FunctionType *FT = Ty->getAs<FunctionType>(); 1276 if (FT) { 1277 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1278 if (Proto->isNothrow(Ctx)) 1279 return false; 1280 } 1281 return true; 1282} 1283 1284CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1285 // Compute the callee type. 1286 QualType calleeType = C->getCallee()->getType(); 1287 if (calleeType == Context->BoundMemberTy) { 1288 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1289 1290 // We should only get a null bound type if processing a dependent 1291 // CFG. Recover by assuming nothing. 1292 if (!boundType.isNull()) calleeType = boundType; 1293 } 1294 1295 // If this is a call to a no-return function, this stops the block here. 1296 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1297 1298 bool AddEHEdge = false; 1299 1300 // Languages without exceptions are assumed to not throw. 1301 if (Context->getLangOpts().Exceptions) { 1302 if (BuildOpts.AddEHEdges) 1303 AddEHEdge = true; 1304 } 1305 1306 if (FunctionDecl *FD = C->getDirectCallee()) { 1307 if (FD->hasAttr<NoReturnAttr>()) 1308 NoReturn = true; 1309 if (FD->hasAttr<NoThrowAttr>()) 1310 AddEHEdge = false; 1311 } 1312 1313 if (!CanThrow(C->getCallee(), *Context)) 1314 AddEHEdge = false; 1315 1316 if (!NoReturn && !AddEHEdge) 1317 return VisitStmt(C, asc.withAlwaysAdd(true)); 1318 1319 if (Block) { 1320 Succ = Block; 1321 if (badCFG) 1322 return 0; 1323 } 1324 1325 if (NoReturn) 1326 Block = createNoReturnBlock(); 1327 else 1328 Block = createBlock(); 1329 1330 appendStmt(Block, C); 1331 1332 if (AddEHEdge) { 1333 // Add exceptional edges. 1334 if (TryTerminatedBlock) 1335 addSuccessor(Block, TryTerminatedBlock); 1336 else 1337 addSuccessor(Block, &cfg->getExit()); 1338 } 1339 1340 return VisitChildren(C); 1341} 1342 1343CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1344 AddStmtChoice asc) { 1345 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1346 appendStmt(ConfluenceBlock, C); 1347 if (badCFG) 1348 return 0; 1349 1350 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1351 Succ = ConfluenceBlock; 1352 Block = NULL; 1353 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1354 if (badCFG) 1355 return 0; 1356 1357 Succ = ConfluenceBlock; 1358 Block = NULL; 1359 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1360 if (badCFG) 1361 return 0; 1362 1363 Block = createBlock(false); 1364 // See if this is a known constant. 1365 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1366 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1367 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1368 Block->setTerminator(C); 1369 return addStmt(C->getCond()); 1370} 1371 1372 1373CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1374 addLocalScopeAndDtors(C); 1375 CFGBlock *LastBlock = Block; 1376 1377 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1378 I != E; ++I ) { 1379 // If we hit a segment of code just containing ';' (NullStmts), we can 1380 // get a null block back. In such cases, just use the LastBlock 1381 if (CFGBlock *newBlock = addStmt(*I)) 1382 LastBlock = newBlock; 1383 1384 if (badCFG) 1385 return NULL; 1386 } 1387 1388 return LastBlock; 1389} 1390 1391CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1392 AddStmtChoice asc) { 1393 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1394 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1395 1396 // Create the confluence block that will "merge" the results of the ternary 1397 // expression. 1398 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1399 appendStmt(ConfluenceBlock, C); 1400 if (badCFG) 1401 return 0; 1402 1403 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1404 1405 // Create a block for the LHS expression if there is an LHS expression. A 1406 // GCC extension allows LHS to be NULL, causing the condition to be the 1407 // value that is returned instead. 1408 // e.g: x ?: y is shorthand for: x ? x : y; 1409 Succ = ConfluenceBlock; 1410 Block = NULL; 1411 CFGBlock *LHSBlock = 0; 1412 const Expr *trueExpr = C->getTrueExpr(); 1413 if (trueExpr != opaqueValue) { 1414 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1415 if (badCFG) 1416 return 0; 1417 Block = NULL; 1418 } 1419 else 1420 LHSBlock = ConfluenceBlock; 1421 1422 // Create the block for the RHS expression. 1423 Succ = ConfluenceBlock; 1424 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1425 if (badCFG) 1426 return 0; 1427 1428 // Create the block that will contain the condition. 1429 Block = createBlock(false); 1430 1431 // See if this is a known constant. 1432 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1433 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1434 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1435 Block->setTerminator(C); 1436 Expr *condExpr = C->getCond(); 1437 1438 if (opaqueValue) { 1439 // Run the condition expression if it's not trivially expressed in 1440 // terms of the opaque value (or if there is no opaque value). 1441 if (condExpr != opaqueValue) 1442 addStmt(condExpr); 1443 1444 // Before that, run the common subexpression if there was one. 1445 // At least one of this or the above will be run. 1446 return addStmt(BCO->getCommon()); 1447 } 1448 1449 return addStmt(condExpr); 1450} 1451 1452CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1453 // Check if the Decl is for an __label__. If so, elide it from the 1454 // CFG entirely. 1455 if (isa<LabelDecl>(*DS->decl_begin())) 1456 return Block; 1457 1458 // This case also handles static_asserts. 1459 if (DS->isSingleDecl()) 1460 return VisitDeclSubExpr(DS); 1461 1462 CFGBlock *B = 0; 1463 1464 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1465 typedef SmallVector<Decl*,10> BufTy; 1466 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1467 1468 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1469 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1470 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1471 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1472 1473 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1474 // automatically freed with the CFG. 1475 DeclGroupRef DG(*I); 1476 Decl *D = *I; 1477 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1478 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1479 1480 // Append the fake DeclStmt to block. 1481 B = VisitDeclSubExpr(DSNew); 1482 } 1483 1484 return B; 1485} 1486 1487/// VisitDeclSubExpr - Utility method to add block-level expressions for 1488/// DeclStmts and initializers in them. 1489CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1490 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1491 Decl *D = DS->getSingleDecl(); 1492 1493 if (isa<StaticAssertDecl>(D)) { 1494 // static_asserts aren't added to the CFG because they do not impact 1495 // runtime semantics. 1496 return Block; 1497 } 1498 1499 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1500 1501 if (!VD) { 1502 autoCreateBlock(); 1503 appendStmt(Block, DS); 1504 return Block; 1505 } 1506 1507 bool IsReference = false; 1508 bool HasTemporaries = false; 1509 1510 // Destructors of temporaries in initialization expression should be called 1511 // after initialization finishes. 1512 Expr *Init = VD->getInit(); 1513 if (Init) { 1514 IsReference = VD->getType()->isReferenceType(); 1515 HasTemporaries = isa<ExprWithCleanups>(Init); 1516 1517 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1518 // Generate destructors for temporaries in initialization expression. 1519 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1520 IsReference); 1521 } 1522 } 1523 1524 autoCreateBlock(); 1525 appendStmt(Block, DS); 1526 1527 // Keep track of the last non-null block, as 'Block' can be nulled out 1528 // if the initializer expression is something like a 'while' in a 1529 // statement-expression. 1530 CFGBlock *LastBlock = Block; 1531 1532 if (Init) { 1533 if (HasTemporaries) { 1534 // For expression with temporaries go directly to subexpression to omit 1535 // generating destructors for the second time. 1536 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init); 1537 if (CFGBlock *newBlock = Visit(EC->getSubExpr())) 1538 LastBlock = newBlock; 1539 } 1540 else { 1541 if (CFGBlock *newBlock = Visit(Init)) 1542 LastBlock = newBlock; 1543 } 1544 } 1545 1546 // If the type of VD is a VLA, then we must process its size expressions. 1547 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1548 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1549 Block = addStmt(VA->getSizeExpr()); 1550 1551 // Remove variable from local scope. 1552 if (ScopePos && VD == *ScopePos) 1553 ++ScopePos; 1554 1555 return Block ? Block : LastBlock; 1556} 1557 1558CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1559 // We may see an if statement in the middle of a basic block, or it may be the 1560 // first statement we are processing. In either case, we create a new basic 1561 // block. First, we create the blocks for the then...else statements, and 1562 // then we create the block containing the if statement. If we were in the 1563 // middle of a block, we stop processing that block. That block is then the 1564 // implicit successor for the "then" and "else" clauses. 1565 1566 // Save local scope position because in case of condition variable ScopePos 1567 // won't be restored when traversing AST. 1568 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1569 1570 // Create local scope for possible condition variable. 1571 // Store scope position. Add implicit destructor. 1572 if (VarDecl *VD = I->getConditionVariable()) { 1573 LocalScope::const_iterator BeginScopePos = ScopePos; 1574 addLocalScopeForVarDecl(VD); 1575 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1576 } 1577 1578 // The block we were processing is now finished. Make it the successor 1579 // block. 1580 if (Block) { 1581 Succ = Block; 1582 if (badCFG) 1583 return 0; 1584 } 1585 1586 // Process the false branch. 1587 CFGBlock *ElseBlock = Succ; 1588 1589 if (Stmt *Else = I->getElse()) { 1590 SaveAndRestore<CFGBlock*> sv(Succ); 1591 1592 // NULL out Block so that the recursive call to Visit will 1593 // create a new basic block. 1594 Block = NULL; 1595 1596 // If branch is not a compound statement create implicit scope 1597 // and add destructors. 1598 if (!isa<CompoundStmt>(Else)) 1599 addLocalScopeAndDtors(Else); 1600 1601 ElseBlock = addStmt(Else); 1602 1603 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1604 ElseBlock = sv.get(); 1605 else if (Block) { 1606 if (badCFG) 1607 return 0; 1608 } 1609 } 1610 1611 // Process the true branch. 1612 CFGBlock *ThenBlock; 1613 { 1614 Stmt *Then = I->getThen(); 1615 assert(Then); 1616 SaveAndRestore<CFGBlock*> sv(Succ); 1617 Block = NULL; 1618 1619 // If branch is not a compound statement create implicit scope 1620 // and add destructors. 1621 if (!isa<CompoundStmt>(Then)) 1622 addLocalScopeAndDtors(Then); 1623 1624 ThenBlock = addStmt(Then); 1625 1626 if (!ThenBlock) { 1627 // We can reach here if the "then" body has all NullStmts. 1628 // Create an empty block so we can distinguish between true and false 1629 // branches in path-sensitive analyses. 1630 ThenBlock = createBlock(false); 1631 addSuccessor(ThenBlock, sv.get()); 1632 } else if (Block) { 1633 if (badCFG) 1634 return 0; 1635 } 1636 } 1637 1638 // Now create a new block containing the if statement. 1639 Block = createBlock(false); 1640 1641 // Set the terminator of the new block to the If statement. 1642 Block->setTerminator(I); 1643 1644 // See if this is a known constant. 1645 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1646 1647 // Now add the successors. 1648 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1649 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1650 1651 // Add the condition as the last statement in the new block. This may create 1652 // new blocks as the condition may contain control-flow. Any newly created 1653 // blocks will be pointed to be "Block". 1654 Block = addStmt(I->getCond()); 1655 1656 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1657 // and the condition variable initialization to the CFG. 1658 if (VarDecl *VD = I->getConditionVariable()) { 1659 if (Expr *Init = VD->getInit()) { 1660 autoCreateBlock(); 1661 appendStmt(Block, I->getConditionVariableDeclStmt()); 1662 addStmt(Init); 1663 } 1664 } 1665 1666 return Block; 1667} 1668 1669 1670CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1671 // If we were in the middle of a block we stop processing that block. 1672 // 1673 // NOTE: If a "return" appears in the middle of a block, this means that the 1674 // code afterwards is DEAD (unreachable). We still keep a basic block 1675 // for that code; a simple "mark-and-sweep" from the entry block will be 1676 // able to report such dead blocks. 1677 1678 // Create the new block. 1679 Block = createBlock(false); 1680 1681 // The Exit block is the only successor. 1682 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1683 addSuccessor(Block, &cfg->getExit()); 1684 1685 // Add the return statement to the block. This may create new blocks if R 1686 // contains control-flow (short-circuit operations). 1687 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1688} 1689 1690CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1691 // Get the block of the labeled statement. Add it to our map. 1692 addStmt(L->getSubStmt()); 1693 CFGBlock *LabelBlock = Block; 1694 1695 if (!LabelBlock) // This can happen when the body is empty, i.e. 1696 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1697 1698 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1699 "label already in map"); 1700 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1701 1702 // Labels partition blocks, so this is the end of the basic block we were 1703 // processing (L is the block's label). Because this is label (and we have 1704 // already processed the substatement) there is no extra control-flow to worry 1705 // about. 1706 LabelBlock->setLabel(L); 1707 if (badCFG) 1708 return 0; 1709 1710 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1711 Block = NULL; 1712 1713 // This block is now the implicit successor of other blocks. 1714 Succ = LabelBlock; 1715 1716 return LabelBlock; 1717} 1718 1719CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1720 // Goto is a control-flow statement. Thus we stop processing the current 1721 // block and create a new one. 1722 1723 Block = createBlock(false); 1724 Block->setTerminator(G); 1725 1726 // If we already know the mapping to the label block add the successor now. 1727 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1728 1729 if (I == LabelMap.end()) 1730 // We will need to backpatch this block later. 1731 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1732 else { 1733 JumpTarget JT = I->second; 1734 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1735 addSuccessor(Block, JT.block); 1736 } 1737 1738 return Block; 1739} 1740 1741CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1742 CFGBlock *LoopSuccessor = NULL; 1743 1744 // Save local scope position because in case of condition variable ScopePos 1745 // won't be restored when traversing AST. 1746 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1747 1748 // Create local scope for init statement and possible condition variable. 1749 // Add destructor for init statement and condition variable. 1750 // Store scope position for continue statement. 1751 if (Stmt *Init = F->getInit()) 1752 addLocalScopeForStmt(Init); 1753 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1754 1755 if (VarDecl *VD = F->getConditionVariable()) 1756 addLocalScopeForVarDecl(VD); 1757 LocalScope::const_iterator ContinueScopePos = ScopePos; 1758 1759 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1760 1761 // "for" is a control-flow statement. Thus we stop processing the current 1762 // block. 1763 if (Block) { 1764 if (badCFG) 1765 return 0; 1766 LoopSuccessor = Block; 1767 } else 1768 LoopSuccessor = Succ; 1769 1770 // Save the current value for the break targets. 1771 // All breaks should go to the code following the loop. 1772 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1773 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1774 1775 // Because of short-circuit evaluation, the condition of the loop can span 1776 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1777 // evaluate the condition. 1778 CFGBlock *ExitConditionBlock = createBlock(false); 1779 CFGBlock *EntryConditionBlock = ExitConditionBlock; 1780 1781 // Set the terminator for the "exit" condition block. 1782 ExitConditionBlock->setTerminator(F); 1783 1784 // Now add the actual condition to the condition block. Because the condition 1785 // itself may contain control-flow, new blocks may be created. 1786 if (Stmt *C = F->getCond()) { 1787 Block = ExitConditionBlock; 1788 EntryConditionBlock = addStmt(C); 1789 if (badCFG) 1790 return 0; 1791 assert(Block == EntryConditionBlock || 1792 (Block == 0 && EntryConditionBlock == Succ)); 1793 1794 // If this block contains a condition variable, add both the condition 1795 // variable and initializer to the CFG. 1796 if (VarDecl *VD = F->getConditionVariable()) { 1797 if (Expr *Init = VD->getInit()) { 1798 autoCreateBlock(); 1799 appendStmt(Block, F->getConditionVariableDeclStmt()); 1800 EntryConditionBlock = addStmt(Init); 1801 assert(Block == EntryConditionBlock); 1802 } 1803 } 1804 1805 if (Block) { 1806 if (badCFG) 1807 return 0; 1808 } 1809 } 1810 1811 // The condition block is the implicit successor for the loop body as well as 1812 // any code above the loop. 1813 Succ = EntryConditionBlock; 1814 1815 // See if this is a known constant. 1816 TryResult KnownVal(true); 1817 1818 if (F->getCond()) 1819 KnownVal = tryEvaluateBool(F->getCond()); 1820 1821 // Now create the loop body. 1822 { 1823 assert(F->getBody()); 1824 1825 // Save the current values for Block, Succ, and continue targets. 1826 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1827 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1828 1829 // Create a new block to contain the (bottom) of the loop body. 1830 Block = NULL; 1831 1832 // Loop body should end with destructor of Condition variable (if any). 1833 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1834 1835 if (Stmt *I = F->getInc()) { 1836 // Generate increment code in its own basic block. This is the target of 1837 // continue statements. 1838 Succ = addStmt(I); 1839 } else { 1840 // No increment code. Create a special, empty, block that is used as the 1841 // target block for "looping back" to the start of the loop. 1842 assert(Succ == EntryConditionBlock); 1843 Succ = Block ? Block : createBlock(); 1844 } 1845 1846 // Finish up the increment (or empty) block if it hasn't been already. 1847 if (Block) { 1848 assert(Block == Succ); 1849 if (badCFG) 1850 return 0; 1851 Block = 0; 1852 } 1853 1854 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1855 1856 // The starting block for the loop increment is the block that should 1857 // represent the 'loop target' for looping back to the start of the loop. 1858 ContinueJumpTarget.block->setLoopTarget(F); 1859 1860 // If body is not a compound statement create implicit scope 1861 // and add destructors. 1862 if (!isa<CompoundStmt>(F->getBody())) 1863 addLocalScopeAndDtors(F->getBody()); 1864 1865 // Now populate the body block, and in the process create new blocks as we 1866 // walk the body of the loop. 1867 CFGBlock *BodyBlock = addStmt(F->getBody()); 1868 1869 if (!BodyBlock) 1870 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1871 else if (badCFG) 1872 return 0; 1873 1874 // This new body block is a successor to our "exit" condition block. 1875 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1876 } 1877 1878 // Link up the condition block with the code that follows the loop. (the 1879 // false branch). 1880 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1881 1882 // If the loop contains initialization, create a new block for those 1883 // statements. This block can also contain statements that precede the loop. 1884 if (Stmt *I = F->getInit()) { 1885 Block = createBlock(); 1886 return addStmt(I); 1887 } 1888 1889 // There is no loop initialization. We are thus basically a while loop. 1890 // NULL out Block to force lazy block construction. 1891 Block = NULL; 1892 Succ = EntryConditionBlock; 1893 return EntryConditionBlock; 1894} 1895 1896CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1897 if (asc.alwaysAdd(*this, M)) { 1898 autoCreateBlock(); 1899 appendStmt(Block, M); 1900 } 1901 return Visit(M->getBase()); 1902} 1903 1904CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 1905 // Objective-C fast enumeration 'for' statements: 1906 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1907 // 1908 // for ( Type newVariable in collection_expression ) { statements } 1909 // 1910 // becomes: 1911 // 1912 // prologue: 1913 // 1. collection_expression 1914 // T. jump to loop_entry 1915 // loop_entry: 1916 // 1. side-effects of element expression 1917 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1918 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1919 // TB: 1920 // statements 1921 // T. jump to loop_entry 1922 // FB: 1923 // what comes after 1924 // 1925 // and 1926 // 1927 // Type existingItem; 1928 // for ( existingItem in expression ) { statements } 1929 // 1930 // becomes: 1931 // 1932 // the same with newVariable replaced with existingItem; the binding works 1933 // the same except that for one ObjCForCollectionStmt::getElement() returns 1934 // a DeclStmt and the other returns a DeclRefExpr. 1935 // 1936 1937 CFGBlock *LoopSuccessor = 0; 1938 1939 if (Block) { 1940 if (badCFG) 1941 return 0; 1942 LoopSuccessor = Block; 1943 Block = 0; 1944 } else 1945 LoopSuccessor = Succ; 1946 1947 // Build the condition blocks. 1948 CFGBlock *ExitConditionBlock = createBlock(false); 1949 1950 // Set the terminator for the "exit" condition block. 1951 ExitConditionBlock->setTerminator(S); 1952 1953 // The last statement in the block should be the ObjCForCollectionStmt, which 1954 // performs the actual binding to 'element' and determines if there are any 1955 // more items in the collection. 1956 appendStmt(ExitConditionBlock, S); 1957 Block = ExitConditionBlock; 1958 1959 // Walk the 'element' expression to see if there are any side-effects. We 1960 // generate new blocks as necessary. We DON'T add the statement by default to 1961 // the CFG unless it contains control-flow. 1962 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 1963 AddStmtChoice::NotAlwaysAdd); 1964 if (Block) { 1965 if (badCFG) 1966 return 0; 1967 Block = 0; 1968 } 1969 1970 // The condition block is the implicit successor for the loop body as well as 1971 // any code above the loop. 1972 Succ = EntryConditionBlock; 1973 1974 // Now create the true branch. 1975 { 1976 // Save the current values for Succ, continue and break targets. 1977 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1978 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1979 save_break(BreakJumpTarget); 1980 1981 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1982 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1983 1984 CFGBlock *BodyBlock = addStmt(S->getBody()); 1985 1986 if (!BodyBlock) 1987 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1988 else if (Block) { 1989 if (badCFG) 1990 return 0; 1991 } 1992 1993 // This new body block is a successor to our "exit" condition block. 1994 addSuccessor(ExitConditionBlock, BodyBlock); 1995 } 1996 1997 // Link up the condition block with the code that follows the loop. 1998 // (the false branch). 1999 addSuccessor(ExitConditionBlock, LoopSuccessor); 2000 2001 // Now create a prologue block to contain the collection expression. 2002 Block = createBlock(); 2003 return addStmt(S->getCollection()); 2004} 2005 2006CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) { 2007 // Inline the body. 2008 return addStmt(S->getSubStmt()); 2009 // TODO: consider adding cleanups for the end of @autoreleasepool scope. 2010} 2011 2012CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 2013 // FIXME: Add locking 'primitives' to CFG for @synchronized. 2014 2015 // Inline the body. 2016 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 2017 2018 // The sync body starts its own basic block. This makes it a little easier 2019 // for diagnostic clients. 2020 if (SyncBlock) { 2021 if (badCFG) 2022 return 0; 2023 2024 Block = 0; 2025 Succ = SyncBlock; 2026 } 2027 2028 // Add the @synchronized to the CFG. 2029 autoCreateBlock(); 2030 appendStmt(Block, S); 2031 2032 // Inline the sync expression. 2033 return addStmt(S->getSynchExpr()); 2034} 2035 2036CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 2037 // FIXME 2038 return NYS(); 2039} 2040 2041CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) { 2042 autoCreateBlock(); 2043 2044 // Add the PseudoObject as the last thing. 2045 appendStmt(Block, E); 2046 2047 CFGBlock *lastBlock = Block; 2048 2049 // Before that, evaluate all of the semantics in order. In 2050 // CFG-land, that means appending them in reverse order. 2051 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) { 2052 Expr *Semantic = E->getSemanticExpr(--i); 2053 2054 // If the semantic is an opaque value, we're being asked to bind 2055 // it to its source expression. 2056 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic)) 2057 Semantic = OVE->getSourceExpr(); 2058 2059 if (CFGBlock *B = Visit(Semantic)) 2060 lastBlock = B; 2061 } 2062 2063 return lastBlock; 2064} 2065 2066CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 2067 CFGBlock *LoopSuccessor = NULL; 2068 2069 // Save local scope position because in case of condition variable ScopePos 2070 // won't be restored when traversing AST. 2071 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2072 2073 // Create local scope for possible condition variable. 2074 // Store scope position for continue statement. 2075 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 2076 if (VarDecl *VD = W->getConditionVariable()) { 2077 addLocalScopeForVarDecl(VD); 2078 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2079 } 2080 2081 // "while" is a control-flow statement. Thus we stop processing the current 2082 // block. 2083 if (Block) { 2084 if (badCFG) 2085 return 0; 2086 LoopSuccessor = Block; 2087 Block = 0; 2088 } else 2089 LoopSuccessor = Succ; 2090 2091 // Because of short-circuit evaluation, the condition of the loop can span 2092 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2093 // evaluate the condition. 2094 CFGBlock *ExitConditionBlock = createBlock(false); 2095 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2096 2097 // Set the terminator for the "exit" condition block. 2098 ExitConditionBlock->setTerminator(W); 2099 2100 // Now add the actual condition to the condition block. Because the condition 2101 // itself may contain control-flow, new blocks may be created. Thus we update 2102 // "Succ" after adding the condition. 2103 if (Stmt *C = W->getCond()) { 2104 Block = ExitConditionBlock; 2105 EntryConditionBlock = addStmt(C); 2106 // The condition might finish the current 'Block'. 2107 Block = EntryConditionBlock; 2108 2109 // If this block contains a condition variable, add both the condition 2110 // variable and initializer to the CFG. 2111 if (VarDecl *VD = W->getConditionVariable()) { 2112 if (Expr *Init = VD->getInit()) { 2113 autoCreateBlock(); 2114 appendStmt(Block, W->getConditionVariableDeclStmt()); 2115 EntryConditionBlock = addStmt(Init); 2116 assert(Block == EntryConditionBlock); 2117 } 2118 } 2119 2120 if (Block) { 2121 if (badCFG) 2122 return 0; 2123 } 2124 } 2125 2126 // The condition block is the implicit successor for the loop body as well as 2127 // any code above the loop. 2128 Succ = EntryConditionBlock; 2129 2130 // See if this is a known constant. 2131 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 2132 2133 // Process the loop body. 2134 { 2135 assert(W->getBody()); 2136 2137 // Save the current values for Block, Succ, and continue and break targets 2138 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2139 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2140 save_break(BreakJumpTarget); 2141 2142 // Create an empty block to represent the transition block for looping back 2143 // to the head of the loop. 2144 Block = 0; 2145 assert(Succ == EntryConditionBlock); 2146 Succ = createBlock(); 2147 Succ->setLoopTarget(W); 2148 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 2149 2150 // All breaks should go to the code following the loop. 2151 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2152 2153 // NULL out Block to force lazy instantiation of blocks for the body. 2154 Block = NULL; 2155 2156 // Loop body should end with destructor of Condition variable (if any). 2157 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2158 2159 // If body is not a compound statement create implicit scope 2160 // and add destructors. 2161 if (!isa<CompoundStmt>(W->getBody())) 2162 addLocalScopeAndDtors(W->getBody()); 2163 2164 // Create the body. The returned block is the entry to the loop body. 2165 CFGBlock *BodyBlock = addStmt(W->getBody()); 2166 2167 if (!BodyBlock) 2168 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2169 else if (Block) { 2170 if (badCFG) 2171 return 0; 2172 } 2173 2174 // Add the loop body entry as a successor to the condition. 2175 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2176 } 2177 2178 // Link up the condition block with the code that follows the loop. (the 2179 // false branch). 2180 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2181 2182 // There can be no more statements in the condition block since we loop back 2183 // to this block. NULL out Block to force lazy creation of another block. 2184 Block = NULL; 2185 2186 // Return the condition block, which is the dominating block for the loop. 2187 Succ = EntryConditionBlock; 2188 return EntryConditionBlock; 2189} 2190 2191 2192CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2193 // FIXME: For now we pretend that @catch and the code it contains does not 2194 // exit. 2195 return Block; 2196} 2197 2198CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2199 // FIXME: This isn't complete. We basically treat @throw like a return 2200 // statement. 2201 2202 // If we were in the middle of a block we stop processing that block. 2203 if (badCFG) 2204 return 0; 2205 2206 // Create the new block. 2207 Block = createBlock(false); 2208 2209 // The Exit block is the only successor. 2210 addSuccessor(Block, &cfg->getExit()); 2211 2212 // Add the statement to the block. This may create new blocks if S contains 2213 // control-flow (short-circuit operations). 2214 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2215} 2216 2217CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2218 // If we were in the middle of a block we stop processing that block. 2219 if (badCFG) 2220 return 0; 2221 2222 // Create the new block. 2223 Block = createBlock(false); 2224 2225 if (TryTerminatedBlock) 2226 // The current try statement is the only successor. 2227 addSuccessor(Block, TryTerminatedBlock); 2228 else 2229 // otherwise the Exit block is the only successor. 2230 addSuccessor(Block, &cfg->getExit()); 2231 2232 // Add the statement to the block. This may create new blocks if S contains 2233 // control-flow (short-circuit operations). 2234 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2235} 2236 2237CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2238 CFGBlock *LoopSuccessor = NULL; 2239 2240 // "do...while" is a control-flow statement. Thus we stop processing the 2241 // current block. 2242 if (Block) { 2243 if (badCFG) 2244 return 0; 2245 LoopSuccessor = Block; 2246 } else 2247 LoopSuccessor = Succ; 2248 2249 // Because of short-circuit evaluation, the condition of the loop can span 2250 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2251 // evaluate the condition. 2252 CFGBlock *ExitConditionBlock = createBlock(false); 2253 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2254 2255 // Set the terminator for the "exit" condition block. 2256 ExitConditionBlock->setTerminator(D); 2257 2258 // Now add the actual condition to the condition block. Because the condition 2259 // itself may contain control-flow, new blocks may be created. 2260 if (Stmt *C = D->getCond()) { 2261 Block = ExitConditionBlock; 2262 EntryConditionBlock = addStmt(C); 2263 if (Block) { 2264 if (badCFG) 2265 return 0; 2266 } 2267 } 2268 2269 // The condition block is the implicit successor for the loop body. 2270 Succ = EntryConditionBlock; 2271 2272 // See if this is a known constant. 2273 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2274 2275 // Process the loop body. 2276 CFGBlock *BodyBlock = NULL; 2277 { 2278 assert(D->getBody()); 2279 2280 // Save the current values for Block, Succ, and continue and break targets 2281 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2282 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2283 save_break(BreakJumpTarget); 2284 2285 // All continues within this loop should go to the condition block 2286 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2287 2288 // All breaks should go to the code following the loop. 2289 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2290 2291 // NULL out Block to force lazy instantiation of blocks for the body. 2292 Block = NULL; 2293 2294 // If body is not a compound statement create implicit scope 2295 // and add destructors. 2296 if (!isa<CompoundStmt>(D->getBody())) 2297 addLocalScopeAndDtors(D->getBody()); 2298 2299 // Create the body. The returned block is the entry to the loop body. 2300 BodyBlock = addStmt(D->getBody()); 2301 2302 if (!BodyBlock) 2303 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2304 else if (Block) { 2305 if (badCFG) 2306 return 0; 2307 } 2308 2309 if (!KnownVal.isFalse()) { 2310 // Add an intermediate block between the BodyBlock and the 2311 // ExitConditionBlock to represent the "loop back" transition. Create an 2312 // empty block to represent the transition block for looping back to the 2313 // head of the loop. 2314 // FIXME: Can we do this more efficiently without adding another block? 2315 Block = NULL; 2316 Succ = BodyBlock; 2317 CFGBlock *LoopBackBlock = createBlock(); 2318 LoopBackBlock->setLoopTarget(D); 2319 2320 // Add the loop body entry as a successor to the condition. 2321 addSuccessor(ExitConditionBlock, LoopBackBlock); 2322 } 2323 else 2324 addSuccessor(ExitConditionBlock, NULL); 2325 } 2326 2327 // Link up the condition block with the code that follows the loop. 2328 // (the false branch). 2329 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2330 2331 // There can be no more statements in the body block(s) since we loop back to 2332 // the body. NULL out Block to force lazy creation of another block. 2333 Block = NULL; 2334 2335 // Return the loop body, which is the dominating block for the loop. 2336 Succ = BodyBlock; 2337 return BodyBlock; 2338} 2339 2340CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2341 // "continue" is a control-flow statement. Thus we stop processing the 2342 // current block. 2343 if (badCFG) 2344 return 0; 2345 2346 // Now create a new block that ends with the continue statement. 2347 Block = createBlock(false); 2348 Block->setTerminator(C); 2349 2350 // If there is no target for the continue, then we are looking at an 2351 // incomplete AST. This means the CFG cannot be constructed. 2352 if (ContinueJumpTarget.block) { 2353 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2354 addSuccessor(Block, ContinueJumpTarget.block); 2355 } else 2356 badCFG = true; 2357 2358 return Block; 2359} 2360 2361CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2362 AddStmtChoice asc) { 2363 2364 if (asc.alwaysAdd(*this, E)) { 2365 autoCreateBlock(); 2366 appendStmt(Block, E); 2367 } 2368 2369 // VLA types have expressions that must be evaluated. 2370 CFGBlock *lastBlock = Block; 2371 2372 if (E->isArgumentType()) { 2373 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2374 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2375 lastBlock = addStmt(VA->getSizeExpr()); 2376 } 2377 return lastBlock; 2378} 2379 2380/// VisitStmtExpr - Utility method to handle (nested) statement 2381/// expressions (a GCC extension). 2382CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2383 if (asc.alwaysAdd(*this, SE)) { 2384 autoCreateBlock(); 2385 appendStmt(Block, SE); 2386 } 2387 return VisitCompoundStmt(SE->getSubStmt()); 2388} 2389 2390CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2391 // "switch" is a control-flow statement. Thus we stop processing the current 2392 // block. 2393 CFGBlock *SwitchSuccessor = NULL; 2394 2395 // Save local scope position because in case of condition variable ScopePos 2396 // won't be restored when traversing AST. 2397 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2398 2399 // Create local scope for possible condition variable. 2400 // Store scope position. Add implicit destructor. 2401 if (VarDecl *VD = Terminator->getConditionVariable()) { 2402 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2403 addLocalScopeForVarDecl(VD); 2404 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2405 } 2406 2407 if (Block) { 2408 if (badCFG) 2409 return 0; 2410 SwitchSuccessor = Block; 2411 } else SwitchSuccessor = Succ; 2412 2413 // Save the current "switch" context. 2414 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2415 save_default(DefaultCaseBlock); 2416 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2417 2418 // Set the "default" case to be the block after the switch statement. If the 2419 // switch statement contains a "default:", this value will be overwritten with 2420 // the block for that code. 2421 DefaultCaseBlock = SwitchSuccessor; 2422 2423 // Create a new block that will contain the switch statement. 2424 SwitchTerminatedBlock = createBlock(false); 2425 2426 // Now process the switch body. The code after the switch is the implicit 2427 // successor. 2428 Succ = SwitchSuccessor; 2429 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2430 2431 // When visiting the body, the case statements should automatically get linked 2432 // up to the switch. We also don't keep a pointer to the body, since all 2433 // control-flow from the switch goes to case/default statements. 2434 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2435 Block = NULL; 2436 2437 // For pruning unreachable case statements, save the current state 2438 // for tracking the condition value. 2439 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2440 false); 2441 2442 // Determine if the switch condition can be explicitly evaluated. 2443 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2444 Expr::EvalResult result; 2445 bool b = tryEvaluate(Terminator->getCond(), result); 2446 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2447 b ? &result : 0); 2448 2449 // If body is not a compound statement create implicit scope 2450 // and add destructors. 2451 if (!isa<CompoundStmt>(Terminator->getBody())) 2452 addLocalScopeAndDtors(Terminator->getBody()); 2453 2454 addStmt(Terminator->getBody()); 2455 if (Block) { 2456 if (badCFG) 2457 return 0; 2458 } 2459 2460 // If we have no "default:" case, the default transition is to the code 2461 // following the switch body. Moreover, take into account if all the 2462 // cases of a switch are covered (e.g., switching on an enum value). 2463 addSuccessor(SwitchTerminatedBlock, 2464 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2465 ? 0 : DefaultCaseBlock); 2466 2467 // Add the terminator and condition in the switch block. 2468 SwitchTerminatedBlock->setTerminator(Terminator); 2469 Block = SwitchTerminatedBlock; 2470 Block = addStmt(Terminator->getCond()); 2471 2472 // Finally, if the SwitchStmt contains a condition variable, add both the 2473 // SwitchStmt and the condition variable initialization to the CFG. 2474 if (VarDecl *VD = Terminator->getConditionVariable()) { 2475 if (Expr *Init = VD->getInit()) { 2476 autoCreateBlock(); 2477 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2478 addStmt(Init); 2479 } 2480 } 2481 2482 return Block; 2483} 2484 2485static bool shouldAddCase(bool &switchExclusivelyCovered, 2486 const Expr::EvalResult *switchCond, 2487 const CaseStmt *CS, 2488 ASTContext &Ctx) { 2489 if (!switchCond) 2490 return true; 2491 2492 bool addCase = false; 2493 2494 if (!switchExclusivelyCovered) { 2495 if (switchCond->Val.isInt()) { 2496 // Evaluate the LHS of the case value. 2497 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2498 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2499 2500 if (condInt == lhsInt) { 2501 addCase = true; 2502 switchExclusivelyCovered = true; 2503 } 2504 else if (condInt < lhsInt) { 2505 if (const Expr *RHS = CS->getRHS()) { 2506 // Evaluate the RHS of the case value. 2507 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2508 if (V2 <= condInt) { 2509 addCase = true; 2510 switchExclusivelyCovered = true; 2511 } 2512 } 2513 } 2514 } 2515 else 2516 addCase = true; 2517 } 2518 return addCase; 2519} 2520 2521CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2522 // CaseStmts are essentially labels, so they are the first statement in a 2523 // block. 2524 CFGBlock *TopBlock = 0, *LastBlock = 0; 2525 2526 if (Stmt *Sub = CS->getSubStmt()) { 2527 // For deeply nested chains of CaseStmts, instead of doing a recursion 2528 // (which can blow out the stack), manually unroll and create blocks 2529 // along the way. 2530 while (isa<CaseStmt>(Sub)) { 2531 CFGBlock *currentBlock = createBlock(false); 2532 currentBlock->setLabel(CS); 2533 2534 if (TopBlock) 2535 addSuccessor(LastBlock, currentBlock); 2536 else 2537 TopBlock = currentBlock; 2538 2539 addSuccessor(SwitchTerminatedBlock, 2540 shouldAddCase(switchExclusivelyCovered, switchCond, 2541 CS, *Context) 2542 ? currentBlock : 0); 2543 2544 LastBlock = currentBlock; 2545 CS = cast<CaseStmt>(Sub); 2546 Sub = CS->getSubStmt(); 2547 } 2548 2549 addStmt(Sub); 2550 } 2551 2552 CFGBlock *CaseBlock = Block; 2553 if (!CaseBlock) 2554 CaseBlock = createBlock(); 2555 2556 // Cases statements partition blocks, so this is the top of the basic block we 2557 // were processing (the "case XXX:" is the label). 2558 CaseBlock->setLabel(CS); 2559 2560 if (badCFG) 2561 return 0; 2562 2563 // Add this block to the list of successors for the block with the switch 2564 // statement. 2565 assert(SwitchTerminatedBlock); 2566 addSuccessor(SwitchTerminatedBlock, 2567 shouldAddCase(switchExclusivelyCovered, switchCond, 2568 CS, *Context) 2569 ? CaseBlock : 0); 2570 2571 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2572 Block = NULL; 2573 2574 if (TopBlock) { 2575 addSuccessor(LastBlock, CaseBlock); 2576 Succ = TopBlock; 2577 } else { 2578 // This block is now the implicit successor of other blocks. 2579 Succ = CaseBlock; 2580 } 2581 2582 return Succ; 2583} 2584 2585CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2586 if (Terminator->getSubStmt()) 2587 addStmt(Terminator->getSubStmt()); 2588 2589 DefaultCaseBlock = Block; 2590 2591 if (!DefaultCaseBlock) 2592 DefaultCaseBlock = createBlock(); 2593 2594 // Default statements partition blocks, so this is the top of the basic block 2595 // we were processing (the "default:" is the label). 2596 DefaultCaseBlock->setLabel(Terminator); 2597 2598 if (badCFG) 2599 return 0; 2600 2601 // Unlike case statements, we don't add the default block to the successors 2602 // for the switch statement immediately. This is done when we finish 2603 // processing the switch statement. This allows for the default case 2604 // (including a fall-through to the code after the switch statement) to always 2605 // be the last successor of a switch-terminated block. 2606 2607 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2608 Block = NULL; 2609 2610 // This block is now the implicit successor of other blocks. 2611 Succ = DefaultCaseBlock; 2612 2613 return DefaultCaseBlock; 2614} 2615 2616CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2617 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2618 // current block. 2619 CFGBlock *TrySuccessor = NULL; 2620 2621 if (Block) { 2622 if (badCFG) 2623 return 0; 2624 TrySuccessor = Block; 2625 } else TrySuccessor = Succ; 2626 2627 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2628 2629 // Create a new block that will contain the try statement. 2630 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2631 // Add the terminator in the try block. 2632 NewTryTerminatedBlock->setTerminator(Terminator); 2633 2634 bool HasCatchAll = false; 2635 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2636 // The code after the try is the implicit successor. 2637 Succ = TrySuccessor; 2638 CXXCatchStmt *CS = Terminator->getHandler(h); 2639 if (CS->getExceptionDecl() == 0) { 2640 HasCatchAll = true; 2641 } 2642 Block = NULL; 2643 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2644 if (CatchBlock == 0) 2645 return 0; 2646 // Add this block to the list of successors for the block with the try 2647 // statement. 2648 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2649 } 2650 if (!HasCatchAll) { 2651 if (PrevTryTerminatedBlock) 2652 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2653 else 2654 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2655 } 2656 2657 // The code after the try is the implicit successor. 2658 Succ = TrySuccessor; 2659 2660 // Save the current "try" context. 2661 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2662 cfg->addTryDispatchBlock(TryTerminatedBlock); 2663 2664 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2665 Block = NULL; 2666 Block = addStmt(Terminator->getTryBlock()); 2667 return Block; 2668} 2669 2670CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2671 // CXXCatchStmt are treated like labels, so they are the first statement in a 2672 // block. 2673 2674 // Save local scope position because in case of exception variable ScopePos 2675 // won't be restored when traversing AST. 2676 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2677 2678 // Create local scope for possible exception variable. 2679 // Store scope position. Add implicit destructor. 2680 if (VarDecl *VD = CS->getExceptionDecl()) { 2681 LocalScope::const_iterator BeginScopePos = ScopePos; 2682 addLocalScopeForVarDecl(VD); 2683 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2684 } 2685 2686 if (CS->getHandlerBlock()) 2687 addStmt(CS->getHandlerBlock()); 2688 2689 CFGBlock *CatchBlock = Block; 2690 if (!CatchBlock) 2691 CatchBlock = createBlock(); 2692 2693 // CXXCatchStmt is more than just a label. They have semantic meaning 2694 // as well, as they implicitly "initialize" the catch variable. Add 2695 // it to the CFG as a CFGElement so that the control-flow of these 2696 // semantics gets captured. 2697 appendStmt(CatchBlock, CS); 2698 2699 // Also add the CXXCatchStmt as a label, to mirror handling of regular 2700 // labels. 2701 CatchBlock->setLabel(CS); 2702 2703 // Bail out if the CFG is bad. 2704 if (badCFG) 2705 return 0; 2706 2707 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2708 Block = NULL; 2709 2710 return CatchBlock; 2711} 2712 2713CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2714 // C++0x for-range statements are specified as [stmt.ranged]: 2715 // 2716 // { 2717 // auto && __range = range-init; 2718 // for ( auto __begin = begin-expr, 2719 // __end = end-expr; 2720 // __begin != __end; 2721 // ++__begin ) { 2722 // for-range-declaration = *__begin; 2723 // statement 2724 // } 2725 // } 2726 2727 // Save local scope position before the addition of the implicit variables. 2728 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2729 2730 // Create local scopes and destructors for range, begin and end variables. 2731 if (Stmt *Range = S->getRangeStmt()) 2732 addLocalScopeForStmt(Range); 2733 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2734 addLocalScopeForStmt(BeginEnd); 2735 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2736 2737 LocalScope::const_iterator ContinueScopePos = ScopePos; 2738 2739 // "for" is a control-flow statement. Thus we stop processing the current 2740 // block. 2741 CFGBlock *LoopSuccessor = NULL; 2742 if (Block) { 2743 if (badCFG) 2744 return 0; 2745 LoopSuccessor = Block; 2746 } else 2747 LoopSuccessor = Succ; 2748 2749 // Save the current value for the break targets. 2750 // All breaks should go to the code following the loop. 2751 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2752 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2753 2754 // The block for the __begin != __end expression. 2755 CFGBlock *ConditionBlock = createBlock(false); 2756 ConditionBlock->setTerminator(S); 2757 2758 // Now add the actual condition to the condition block. 2759 if (Expr *C = S->getCond()) { 2760 Block = ConditionBlock; 2761 CFGBlock *BeginConditionBlock = addStmt(C); 2762 if (badCFG) 2763 return 0; 2764 assert(BeginConditionBlock == ConditionBlock && 2765 "condition block in for-range was unexpectedly complex"); 2766 (void)BeginConditionBlock; 2767 } 2768 2769 // The condition block is the implicit successor for the loop body as well as 2770 // any code above the loop. 2771 Succ = ConditionBlock; 2772 2773 // See if this is a known constant. 2774 TryResult KnownVal(true); 2775 2776 if (S->getCond()) 2777 KnownVal = tryEvaluateBool(S->getCond()); 2778 2779 // Now create the loop body. 2780 { 2781 assert(S->getBody()); 2782 2783 // Save the current values for Block, Succ, and continue targets. 2784 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2785 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2786 2787 // Generate increment code in its own basic block. This is the target of 2788 // continue statements. 2789 Block = 0; 2790 Succ = addStmt(S->getInc()); 2791 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2792 2793 // The starting block for the loop increment is the block that should 2794 // represent the 'loop target' for looping back to the start of the loop. 2795 ContinueJumpTarget.block->setLoopTarget(S); 2796 2797 // Finish up the increment block and prepare to start the loop body. 2798 assert(Block); 2799 if (badCFG) 2800 return 0; 2801 Block = 0; 2802 2803 2804 // Add implicit scope and dtors for loop variable. 2805 addLocalScopeAndDtors(S->getLoopVarStmt()); 2806 2807 // Populate a new block to contain the loop body and loop variable. 2808 Block = addStmt(S->getBody()); 2809 if (badCFG) 2810 return 0; 2811 Block = addStmt(S->getLoopVarStmt()); 2812 if (badCFG) 2813 return 0; 2814 2815 // This new body block is a successor to our condition block. 2816 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2817 } 2818 2819 // Link up the condition block with the code that follows the loop (the 2820 // false branch). 2821 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2822 2823 // Add the initialization statements. 2824 Block = createBlock(); 2825 addStmt(S->getBeginEndStmt()); 2826 return addStmt(S->getRangeStmt()); 2827} 2828 2829CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2830 AddStmtChoice asc) { 2831 if (BuildOpts.AddImplicitDtors) { 2832 // If adding implicit destructors visit the full expression for adding 2833 // destructors of temporaries. 2834 VisitForTemporaryDtors(E->getSubExpr()); 2835 2836 // Full expression has to be added as CFGStmt so it will be sequenced 2837 // before destructors of it's temporaries. 2838 asc = asc.withAlwaysAdd(true); 2839 } 2840 return Visit(E->getSubExpr(), asc); 2841} 2842 2843CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2844 AddStmtChoice asc) { 2845 if (asc.alwaysAdd(*this, E)) { 2846 autoCreateBlock(); 2847 appendStmt(Block, E); 2848 2849 // We do not want to propagate the AlwaysAdd property. 2850 asc = asc.withAlwaysAdd(false); 2851 } 2852 return Visit(E->getSubExpr(), asc); 2853} 2854 2855CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2856 AddStmtChoice asc) { 2857 autoCreateBlock(); 2858 appendStmt(Block, C); 2859 2860 return VisitChildren(C); 2861} 2862 2863CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2864 AddStmtChoice asc) { 2865 if (asc.alwaysAdd(*this, E)) { 2866 autoCreateBlock(); 2867 appendStmt(Block, E); 2868 // We do not want to propagate the AlwaysAdd property. 2869 asc = asc.withAlwaysAdd(false); 2870 } 2871 return Visit(E->getSubExpr(), asc); 2872} 2873 2874CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2875 AddStmtChoice asc) { 2876 autoCreateBlock(); 2877 appendStmt(Block, C); 2878 return VisitChildren(C); 2879} 2880 2881CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2882 AddStmtChoice asc) { 2883 if (asc.alwaysAdd(*this, E)) { 2884 autoCreateBlock(); 2885 appendStmt(Block, E); 2886 } 2887 return Visit(E->getSubExpr(), AddStmtChoice()); 2888} 2889 2890CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 2891 // Lazily create the indirect-goto dispatch block if there isn't one already. 2892 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 2893 2894 if (!IBlock) { 2895 IBlock = createBlock(false); 2896 cfg->setIndirectGotoBlock(IBlock); 2897 } 2898 2899 // IndirectGoto is a control-flow statement. Thus we stop processing the 2900 // current block and create a new one. 2901 if (badCFG) 2902 return 0; 2903 2904 Block = createBlock(false); 2905 Block->setTerminator(I); 2906 addSuccessor(Block, IBlock); 2907 return addStmt(I->getTarget()); 2908} 2909 2910CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2911tryAgain: 2912 if (!E) { 2913 badCFG = true; 2914 return NULL; 2915 } 2916 switch (E->getStmtClass()) { 2917 default: 2918 return VisitChildrenForTemporaryDtors(E); 2919 2920 case Stmt::BinaryOperatorClass: 2921 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2922 2923 case Stmt::CXXBindTemporaryExprClass: 2924 return VisitCXXBindTemporaryExprForTemporaryDtors( 2925 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2926 2927 case Stmt::BinaryConditionalOperatorClass: 2928 case Stmt::ConditionalOperatorClass: 2929 return VisitConditionalOperatorForTemporaryDtors( 2930 cast<AbstractConditionalOperator>(E), BindToTemporary); 2931 2932 case Stmt::ImplicitCastExprClass: 2933 // For implicit cast we want BindToTemporary to be passed further. 2934 E = cast<CastExpr>(E)->getSubExpr(); 2935 goto tryAgain; 2936 2937 case Stmt::ParenExprClass: 2938 E = cast<ParenExpr>(E)->getSubExpr(); 2939 goto tryAgain; 2940 2941 case Stmt::MaterializeTemporaryExprClass: 2942 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 2943 goto tryAgain; 2944 } 2945} 2946 2947CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2948 // When visiting children for destructors we want to visit them in reverse 2949 // order. Because there's no reverse iterator for children must to reverse 2950 // them in helper vector. 2951 typedef SmallVector<Stmt *, 4> ChildrenVect; 2952 ChildrenVect ChildrenRev; 2953 for (Stmt::child_range I = E->children(); I; ++I) { 2954 if (*I) ChildrenRev.push_back(*I); 2955 } 2956 2957 CFGBlock *B = Block; 2958 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2959 L = ChildrenRev.rend(); I != L; ++I) { 2960 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2961 B = R; 2962 } 2963 return B; 2964} 2965 2966CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2967 if (E->isLogicalOp()) { 2968 // Destructors for temporaries in LHS expression should be called after 2969 // those for RHS expression. Even if this will unnecessarily create a block, 2970 // this block will be used at least by the full expression. 2971 autoCreateBlock(); 2972 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2973 if (badCFG) 2974 return NULL; 2975 2976 Succ = ConfluenceBlock; 2977 Block = NULL; 2978 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2979 2980 if (RHSBlock) { 2981 if (badCFG) 2982 return NULL; 2983 2984 // If RHS expression did produce destructors we need to connect created 2985 // blocks to CFG in same manner as for binary operator itself. 2986 CFGBlock *LHSBlock = createBlock(false); 2987 LHSBlock->setTerminator(CFGTerminator(E, true)); 2988 2989 // For binary operator LHS block is before RHS in list of predecessors 2990 // of ConfluenceBlock. 2991 std::reverse(ConfluenceBlock->pred_begin(), 2992 ConfluenceBlock->pred_end()); 2993 2994 // See if this is a known constant. 2995 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2996 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2997 KnownVal.negate(); 2998 2999 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 3000 // itself. 3001 if (E->getOpcode() == BO_LOr) { 3002 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3003 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3004 } else { 3005 assert (E->getOpcode() == BO_LAnd); 3006 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3007 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3008 } 3009 3010 Block = LHSBlock; 3011 return LHSBlock; 3012 } 3013 3014 Block = ConfluenceBlock; 3015 return ConfluenceBlock; 3016 } 3017 3018 if (E->isAssignmentOp()) { 3019 // For assignment operator (=) LHS expression is visited 3020 // before RHS expression. For destructors visit them in reverse order. 3021 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3022 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3023 return LHSBlock ? LHSBlock : RHSBlock; 3024 } 3025 3026 // For any other binary operator RHS expression is visited before 3027 // LHS expression (order of children). For destructors visit them in reverse 3028 // order. 3029 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3030 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3031 return RHSBlock ? RHSBlock : LHSBlock; 3032} 3033 3034CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 3035 CXXBindTemporaryExpr *E, bool BindToTemporary) { 3036 // First add destructors for temporaries in subexpression. 3037 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 3038 if (!BindToTemporary) { 3039 // If lifetime of temporary is not prolonged (by assigning to constant 3040 // reference) add destructor for it. 3041 3042 // If the destructor is marked as a no-return destructor, we need to create 3043 // a new block for the destructor which does not have as a successor 3044 // anything built thus far. Control won't flow out of this block. 3045 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 3046 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 3047 Block = createNoReturnBlock(); 3048 else 3049 autoCreateBlock(); 3050 3051 appendTemporaryDtor(Block, E); 3052 B = Block; 3053 } 3054 return B; 3055} 3056 3057CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 3058 AbstractConditionalOperator *E, bool BindToTemporary) { 3059 // First add destructors for condition expression. Even if this will 3060 // unnecessarily create a block, this block will be used at least by the full 3061 // expression. 3062 autoCreateBlock(); 3063 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 3064 if (badCFG) 3065 return NULL; 3066 if (BinaryConditionalOperator *BCO 3067 = dyn_cast<BinaryConditionalOperator>(E)) { 3068 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 3069 if (badCFG) 3070 return NULL; 3071 } 3072 3073 // Try to add block with destructors for LHS expression. 3074 CFGBlock *LHSBlock = NULL; 3075 Succ = ConfluenceBlock; 3076 Block = NULL; 3077 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 3078 if (badCFG) 3079 return NULL; 3080 3081 // Try to add block with destructors for RHS expression; 3082 Succ = ConfluenceBlock; 3083 Block = NULL; 3084 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 3085 BindToTemporary); 3086 if (badCFG) 3087 return NULL; 3088 3089 if (!RHSBlock && !LHSBlock) { 3090 // If neither LHS nor RHS expression had temporaries to destroy don't create 3091 // more blocks. 3092 Block = ConfluenceBlock; 3093 return Block; 3094 } 3095 3096 Block = createBlock(false); 3097 Block->setTerminator(CFGTerminator(E, true)); 3098 3099 // See if this is a known constant. 3100 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 3101 3102 if (LHSBlock) { 3103 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 3104 } else if (KnownVal.isFalse()) { 3105 addSuccessor(Block, NULL); 3106 } else { 3107 addSuccessor(Block, ConfluenceBlock); 3108 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 3109 } 3110 3111 if (!RHSBlock) 3112 RHSBlock = ConfluenceBlock; 3113 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 3114 3115 return Block; 3116} 3117 3118} // end anonymous namespace 3119 3120/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 3121/// no successors or predecessors. If this is the first block created in the 3122/// CFG, it is automatically set to be the Entry and Exit of the CFG. 3123CFGBlock *CFG::createBlock() { 3124 bool first_block = begin() == end(); 3125 3126 // Create the block. 3127 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 3128 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this); 3129 Blocks.push_back(Mem, BlkBVC); 3130 3131 // If this is the first block, set it as the Entry and Exit. 3132 if (first_block) 3133 Entry = Exit = &back(); 3134 3135 // Return the block. 3136 return &back(); 3137} 3138 3139/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 3140/// CFG is returned to the caller. 3141CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 3142 const BuildOptions &BO) { 3143 CFGBuilder Builder(C, BO); 3144 return Builder.buildCFG(D, Statement); 3145} 3146 3147const CXXDestructorDecl * 3148CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 3149 switch (getKind()) { 3150 case CFGElement::Invalid: 3151 case CFGElement::Statement: 3152 case CFGElement::Initializer: 3153 llvm_unreachable("getDestructorDecl should only be used with " 3154 "ImplicitDtors"); 3155 case CFGElement::AutomaticObjectDtor: { 3156 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 3157 QualType ty = var->getType(); 3158 ty = ty.getNonReferenceType(); 3159 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3160 ty = arrayType->getElementType(); 3161 } 3162 const RecordType *recordType = ty->getAs<RecordType>(); 3163 const CXXRecordDecl *classDecl = 3164 cast<CXXRecordDecl>(recordType->getDecl()); 3165 return classDecl->getDestructor(); 3166 } 3167 case CFGElement::TemporaryDtor: { 3168 const CXXBindTemporaryExpr *bindExpr = 3169 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 3170 const CXXTemporary *temp = bindExpr->getTemporary(); 3171 return temp->getDestructor(); 3172 } 3173 case CFGElement::BaseDtor: 3174 case CFGElement::MemberDtor: 3175 3176 // Not yet supported. 3177 return 0; 3178 } 3179 llvm_unreachable("getKind() returned bogus value"); 3180} 3181 3182bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3183 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 3184 QualType ty = cdecl->getType(); 3185 return cast<FunctionType>(ty)->getNoReturnAttr(); 3186 } 3187 return false; 3188} 3189 3190//===----------------------------------------------------------------------===// 3191// CFG: Queries for BlkExprs. 3192//===----------------------------------------------------------------------===// 3193 3194namespace { 3195 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3196} 3197 3198static void FindSubExprAssignments(const Stmt *S, 3199 llvm::SmallPtrSet<const Expr*,50>& Set) { 3200 if (!S) 3201 return; 3202 3203 for (Stmt::const_child_range I = S->children(); I; ++I) { 3204 const Stmt *child = *I; 3205 if (!child) 3206 continue; 3207 3208 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3209 if (B->isAssignmentOp()) Set.insert(B); 3210 3211 FindSubExprAssignments(child, Set); 3212 } 3213} 3214 3215static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3216 BlkExprMapTy* M = new BlkExprMapTy(); 3217 3218 // Look for assignments that are used as subexpressions. These are the only 3219 // assignments that we want to *possibly* register as a block-level 3220 // expression. Basically, if an assignment occurs both in a subexpression and 3221 // at the block-level, it is a block-level expression. 3222 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3223 3224 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3225 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3226 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3227 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3228 3229 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3230 3231 // Iterate over the statements again on identify the Expr* and Stmt* at the 3232 // block-level that are block-level expressions. 3233 3234 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3235 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3236 if (!CS) 3237 continue; 3238 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3239 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3240 3241 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3242 // Assignment expressions that are not nested within another 3243 // expression are really "statements" whose value is never used by 3244 // another expression. 3245 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3246 continue; 3247 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3248 // Special handling for statement expressions. The last statement in 3249 // the statement expression is also a block-level expr. 3250 const CompoundStmt *C = SE->getSubStmt(); 3251 if (!C->body_empty()) { 3252 const Stmt *Last = C->body_back(); 3253 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3254 Last = LastEx->IgnoreParens(); 3255 unsigned x = M->size(); 3256 (*M)[Last] = x; 3257 } 3258 } 3259 3260 unsigned x = M->size(); 3261 (*M)[Exp] = x; 3262 } 3263 } 3264 3265 // Look at terminators. The condition is a block-level expression. 3266 3267 Stmt *S = (*I)->getTerminatorCondition(); 3268 3269 if (S && M->find(S) == M->end()) { 3270 unsigned x = M->size(); 3271 (*M)[S] = x; 3272 } 3273 } 3274 3275 return M; 3276} 3277 3278CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3279 assert(S != NULL); 3280 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3281 3282 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3283 BlkExprMapTy::iterator I = M->find(S); 3284 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3285} 3286 3287unsigned CFG::getNumBlkExprs() { 3288 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3289 return M->size(); 3290 3291 // We assume callers interested in the number of BlkExprs will want 3292 // the map constructed if it doesn't already exist. 3293 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3294 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3295} 3296 3297//===----------------------------------------------------------------------===// 3298// Filtered walking of the CFG. 3299//===----------------------------------------------------------------------===// 3300 3301bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3302 const CFGBlock *From, const CFGBlock *To) { 3303 3304 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3305 // If the 'To' has no label or is labeled but the label isn't a 3306 // CaseStmt then filter this edge. 3307 if (const SwitchStmt *S = 3308 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3309 if (S->isAllEnumCasesCovered()) { 3310 const Stmt *L = To->getLabel(); 3311 if (!L || !isa<CaseStmt>(L)) 3312 return true; 3313 } 3314 } 3315 } 3316 3317 return false; 3318} 3319 3320//===----------------------------------------------------------------------===// 3321// Cleanup: CFG dstor. 3322//===----------------------------------------------------------------------===// 3323 3324CFG::~CFG() { 3325 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3326} 3327 3328//===----------------------------------------------------------------------===// 3329// CFG pretty printing 3330//===----------------------------------------------------------------------===// 3331 3332namespace { 3333 3334class StmtPrinterHelper : public PrinterHelper { 3335 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3336 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3337 StmtMapTy StmtMap; 3338 DeclMapTy DeclMap; 3339 signed currentBlock; 3340 unsigned currentStmt; 3341 const LangOptions &LangOpts; 3342public: 3343 3344 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3345 : currentBlock(0), currentStmt(0), LangOpts(LO) 3346 { 3347 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3348 unsigned j = 1; 3349 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3350 BI != BEnd; ++BI, ++j ) { 3351 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3352 const Stmt *stmt= SE->getStmt(); 3353 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3354 StmtMap[stmt] = P; 3355 3356 switch (stmt->getStmtClass()) { 3357 case Stmt::DeclStmtClass: 3358 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3359 break; 3360 case Stmt::IfStmtClass: { 3361 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3362 if (var) 3363 DeclMap[var] = P; 3364 break; 3365 } 3366 case Stmt::ForStmtClass: { 3367 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3368 if (var) 3369 DeclMap[var] = P; 3370 break; 3371 } 3372 case Stmt::WhileStmtClass: { 3373 const VarDecl *var = 3374 cast<WhileStmt>(stmt)->getConditionVariable(); 3375 if (var) 3376 DeclMap[var] = P; 3377 break; 3378 } 3379 case Stmt::SwitchStmtClass: { 3380 const VarDecl *var = 3381 cast<SwitchStmt>(stmt)->getConditionVariable(); 3382 if (var) 3383 DeclMap[var] = P; 3384 break; 3385 } 3386 case Stmt::CXXCatchStmtClass: { 3387 const VarDecl *var = 3388 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3389 if (var) 3390 DeclMap[var] = P; 3391 break; 3392 } 3393 default: 3394 break; 3395 } 3396 } 3397 } 3398 } 3399 } 3400 3401 3402 virtual ~StmtPrinterHelper() {} 3403 3404 const LangOptions &getLangOpts() const { return LangOpts; } 3405 void setBlockID(signed i) { currentBlock = i; } 3406 void setStmtID(unsigned i) { currentStmt = i; } 3407 3408 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3409 StmtMapTy::iterator I = StmtMap.find(S); 3410 3411 if (I == StmtMap.end()) 3412 return false; 3413 3414 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3415 && I->second.second == currentStmt) { 3416 return false; 3417 } 3418 3419 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3420 return true; 3421 } 3422 3423 bool handleDecl(const Decl *D, raw_ostream &OS) { 3424 DeclMapTy::iterator I = DeclMap.find(D); 3425 3426 if (I == DeclMap.end()) 3427 return false; 3428 3429 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3430 && I->second.second == currentStmt) { 3431 return false; 3432 } 3433 3434 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3435 return true; 3436 } 3437}; 3438} // end anonymous namespace 3439 3440 3441namespace { 3442class CFGBlockTerminatorPrint 3443 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3444 3445 raw_ostream &OS; 3446 StmtPrinterHelper* Helper; 3447 PrintingPolicy Policy; 3448public: 3449 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3450 const PrintingPolicy &Policy) 3451 : OS(os), Helper(helper), Policy(Policy) {} 3452 3453 void VisitIfStmt(IfStmt *I) { 3454 OS << "if "; 3455 I->getCond()->printPretty(OS,Helper,Policy); 3456 } 3457 3458 // Default case. 3459 void VisitStmt(Stmt *Terminator) { 3460 Terminator->printPretty(OS, Helper, Policy); 3461 } 3462 3463 void VisitForStmt(ForStmt *F) { 3464 OS << "for (" ; 3465 if (F->getInit()) 3466 OS << "..."; 3467 OS << "; "; 3468 if (Stmt *C = F->getCond()) 3469 C->printPretty(OS, Helper, Policy); 3470 OS << "; "; 3471 if (F->getInc()) 3472 OS << "..."; 3473 OS << ")"; 3474 } 3475 3476 void VisitWhileStmt(WhileStmt *W) { 3477 OS << "while " ; 3478 if (Stmt *C = W->getCond()) 3479 C->printPretty(OS, Helper, Policy); 3480 } 3481 3482 void VisitDoStmt(DoStmt *D) { 3483 OS << "do ... while "; 3484 if (Stmt *C = D->getCond()) 3485 C->printPretty(OS, Helper, Policy); 3486 } 3487 3488 void VisitSwitchStmt(SwitchStmt *Terminator) { 3489 OS << "switch "; 3490 Terminator->getCond()->printPretty(OS, Helper, Policy); 3491 } 3492 3493 void VisitCXXTryStmt(CXXTryStmt *CS) { 3494 OS << "try ..."; 3495 } 3496 3497 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3498 C->getCond()->printPretty(OS, Helper, Policy); 3499 OS << " ? ... : ..."; 3500 } 3501 3502 void VisitChooseExpr(ChooseExpr *C) { 3503 OS << "__builtin_choose_expr( "; 3504 C->getCond()->printPretty(OS, Helper, Policy); 3505 OS << " )"; 3506 } 3507 3508 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3509 OS << "goto *"; 3510 I->getTarget()->printPretty(OS, Helper, Policy); 3511 } 3512 3513 void VisitBinaryOperator(BinaryOperator* B) { 3514 if (!B->isLogicalOp()) { 3515 VisitExpr(B); 3516 return; 3517 } 3518 3519 B->getLHS()->printPretty(OS, Helper, Policy); 3520 3521 switch (B->getOpcode()) { 3522 case BO_LOr: 3523 OS << " || ..."; 3524 return; 3525 case BO_LAnd: 3526 OS << " && ..."; 3527 return; 3528 default: 3529 llvm_unreachable("Invalid logical operator."); 3530 } 3531 } 3532 3533 void VisitExpr(Expr *E) { 3534 E->printPretty(OS, Helper, Policy); 3535 } 3536}; 3537} // end anonymous namespace 3538 3539static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3540 const CFGElement &E) { 3541 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3542 const Stmt *S = CS->getStmt(); 3543 3544 if (Helper) { 3545 3546 // special printing for statement-expressions. 3547 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3548 const CompoundStmt *Sub = SE->getSubStmt(); 3549 3550 if (Sub->children()) { 3551 OS << "({ ... ; "; 3552 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3553 OS << " })\n"; 3554 return; 3555 } 3556 } 3557 // special printing for comma expressions. 3558 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3559 if (B->getOpcode() == BO_Comma) { 3560 OS << "... , "; 3561 Helper->handledStmt(B->getRHS(),OS); 3562 OS << '\n'; 3563 return; 3564 } 3565 } 3566 } 3567 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3568 3569 if (isa<CXXOperatorCallExpr>(S)) { 3570 OS << " (OperatorCall)"; 3571 } 3572 else if (isa<CXXBindTemporaryExpr>(S)) { 3573 OS << " (BindTemporary)"; 3574 } 3575 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) { 3576 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")"; 3577 } 3578 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) { 3579 OS << " (" << CE->getStmtClassName() << ", " 3580 << CE->getCastKindName() 3581 << ", " << CE->getType().getAsString() 3582 << ")"; 3583 } 3584 3585 // Expressions need a newline. 3586 if (isa<Expr>(S)) 3587 OS << '\n'; 3588 3589 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3590 const CXXCtorInitializer *I = IE->getInitializer(); 3591 if (I->isBaseInitializer()) 3592 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3593 else OS << I->getAnyMember()->getName(); 3594 3595 OS << "("; 3596 if (Expr *IE = I->getInit()) 3597 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3598 OS << ")"; 3599 3600 if (I->isBaseInitializer()) 3601 OS << " (Base initializer)\n"; 3602 else OS << " (Member initializer)\n"; 3603 3604 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3605 const VarDecl *VD = DE->getVarDecl(); 3606 Helper->handleDecl(VD, OS); 3607 3608 const Type* T = VD->getType().getTypePtr(); 3609 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3610 T = RT->getPointeeType().getTypePtr(); 3611 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3612 T = ET; 3613 3614 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3615 OS << " (Implicit destructor)\n"; 3616 3617 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3618 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3619 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3620 OS << " (Base object destructor)\n"; 3621 3622 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3623 const FieldDecl *FD = ME->getFieldDecl(); 3624 3625 const Type *T = FD->getType().getTypePtr(); 3626 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3627 T = ET; 3628 3629 OS << "this->" << FD->getName(); 3630 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3631 OS << " (Member object destructor)\n"; 3632 3633 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3634 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3635 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3636 OS << " (Temporary object destructor)\n"; 3637 } 3638} 3639 3640static void print_block(raw_ostream &OS, const CFG* cfg, 3641 const CFGBlock &B, 3642 StmtPrinterHelper* Helper, bool print_edges, 3643 bool ShowColors) { 3644 3645 if (Helper) 3646 Helper->setBlockID(B.getBlockID()); 3647 3648 // Print the header. 3649 if (ShowColors) 3650 OS.changeColor(raw_ostream::YELLOW, true); 3651 3652 OS << "\n [B" << B.getBlockID(); 3653 3654 if (&B == &cfg->getEntry()) 3655 OS << " (ENTRY)]\n"; 3656 else if (&B == &cfg->getExit()) 3657 OS << " (EXIT)]\n"; 3658 else if (&B == cfg->getIndirectGotoBlock()) 3659 OS << " (INDIRECT GOTO DISPATCH)]\n"; 3660 else 3661 OS << "]\n"; 3662 3663 if (ShowColors) 3664 OS.resetColor(); 3665 3666 // Print the label of this block. 3667 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3668 3669 if (print_edges) 3670 OS << " "; 3671 3672 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3673 OS << L->getName(); 3674 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3675 OS << "case "; 3676 C->getLHS()->printPretty(OS, Helper, 3677 PrintingPolicy(Helper->getLangOpts())); 3678 if (C->getRHS()) { 3679 OS << " ... "; 3680 C->getRHS()->printPretty(OS, Helper, 3681 PrintingPolicy(Helper->getLangOpts())); 3682 } 3683 } else if (isa<DefaultStmt>(Label)) 3684 OS << "default"; 3685 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3686 OS << "catch ("; 3687 if (CS->getExceptionDecl()) 3688 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3689 0); 3690 else 3691 OS << "..."; 3692 OS << ")"; 3693 3694 } else 3695 llvm_unreachable("Invalid label statement in CFGBlock."); 3696 3697 OS << ":\n"; 3698 } 3699 3700 // Iterate through the statements in the block and print them. 3701 unsigned j = 1; 3702 3703 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3704 I != E ; ++I, ++j ) { 3705 3706 // Print the statement # in the basic block and the statement itself. 3707 if (print_edges) 3708 OS << " "; 3709 3710 OS << llvm::format("%3d", j) << ": "; 3711 3712 if (Helper) 3713 Helper->setStmtID(j); 3714 3715 print_elem(OS, Helper, *I); 3716 } 3717 3718 // Print the terminator of this block. 3719 if (B.getTerminator()) { 3720 if (ShowColors) 3721 OS.changeColor(raw_ostream::GREEN); 3722 3723 OS << " T: "; 3724 3725 if (Helper) Helper->setBlockID(-1); 3726 3727 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3728 PrintingPolicy(Helper->getLangOpts())); 3729 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3730 OS << '\n'; 3731 3732 if (ShowColors) 3733 OS.resetColor(); 3734 } 3735 3736 if (print_edges) { 3737 // Print the predecessors of this block. 3738 if (!B.pred_empty()) { 3739 const raw_ostream::Colors Color = raw_ostream::BLUE; 3740 if (ShowColors) 3741 OS.changeColor(Color); 3742 OS << " Preds " ; 3743 if (ShowColors) 3744 OS.resetColor(); 3745 OS << '(' << B.pred_size() << "):"; 3746 unsigned i = 0; 3747 3748 if (ShowColors) 3749 OS.changeColor(Color); 3750 3751 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3752 I != E; ++I, ++i) { 3753 3754 if (i == 8 || (i-8) == 0) 3755 OS << "\n "; 3756 3757 OS << " B" << (*I)->getBlockID(); 3758 } 3759 3760 if (ShowColors) 3761 OS.resetColor(); 3762 3763 OS << '\n'; 3764 } 3765 3766 // Print the successors of this block. 3767 if (!B.succ_empty()) { 3768 const raw_ostream::Colors Color = raw_ostream::MAGENTA; 3769 if (ShowColors) 3770 OS.changeColor(Color); 3771 OS << " Succs "; 3772 if (ShowColors) 3773 OS.resetColor(); 3774 OS << '(' << B.succ_size() << "):"; 3775 unsigned i = 0; 3776 3777 if (ShowColors) 3778 OS.changeColor(Color); 3779 3780 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3781 I != E; ++I, ++i) { 3782 3783 if (i == 8 || (i-8) % 10 == 0) 3784 OS << "\n "; 3785 3786 if (*I) 3787 OS << " B" << (*I)->getBlockID(); 3788 else 3789 OS << " NULL"; 3790 } 3791 3792 if (ShowColors) 3793 OS.resetColor(); 3794 OS << '\n'; 3795 } 3796 } 3797} 3798 3799 3800/// dump - A simple pretty printer of a CFG that outputs to stderr. 3801void CFG::dump(const LangOptions &LO, bool ShowColors) const { 3802 print(llvm::errs(), LO, ShowColors); 3803} 3804 3805/// print - A simple pretty printer of a CFG that outputs to an ostream. 3806void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const { 3807 StmtPrinterHelper Helper(this, LO); 3808 3809 // Print the entry block. 3810 print_block(OS, this, getEntry(), &Helper, true, ShowColors); 3811 3812 // Iterate through the CFGBlocks and print them one by one. 3813 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3814 // Skip the entry block, because we already printed it. 3815 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3816 continue; 3817 3818 print_block(OS, this, **I, &Helper, true, ShowColors); 3819 } 3820 3821 // Print the exit block. 3822 print_block(OS, this, getExit(), &Helper, true, ShowColors); 3823 OS << '\n'; 3824 OS.flush(); 3825} 3826 3827/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3828void CFGBlock::dump(const CFG* cfg, const LangOptions &LO, 3829 bool ShowColors) const { 3830 print(llvm::errs(), cfg, LO, ShowColors); 3831} 3832 3833/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3834/// Generally this will only be called from CFG::print. 3835void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3836 const LangOptions &LO, bool ShowColors) const { 3837 StmtPrinterHelper Helper(cfg, LO); 3838 print_block(OS, cfg, *this, &Helper, true, ShowColors); 3839 OS << '\n'; 3840} 3841 3842/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3843void CFGBlock::printTerminator(raw_ostream &OS, 3844 const LangOptions &LO) const { 3845 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3846 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3847} 3848 3849Stmt *CFGBlock::getTerminatorCondition() { 3850 Stmt *Terminator = this->Terminator; 3851 if (!Terminator) 3852 return NULL; 3853 3854 Expr *E = NULL; 3855 3856 switch (Terminator->getStmtClass()) { 3857 default: 3858 break; 3859 3860 case Stmt::ForStmtClass: 3861 E = cast<ForStmt>(Terminator)->getCond(); 3862 break; 3863 3864 case Stmt::WhileStmtClass: 3865 E = cast<WhileStmt>(Terminator)->getCond(); 3866 break; 3867 3868 case Stmt::DoStmtClass: 3869 E = cast<DoStmt>(Terminator)->getCond(); 3870 break; 3871 3872 case Stmt::IfStmtClass: 3873 E = cast<IfStmt>(Terminator)->getCond(); 3874 break; 3875 3876 case Stmt::ChooseExprClass: 3877 E = cast<ChooseExpr>(Terminator)->getCond(); 3878 break; 3879 3880 case Stmt::IndirectGotoStmtClass: 3881 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3882 break; 3883 3884 case Stmt::SwitchStmtClass: 3885 E = cast<SwitchStmt>(Terminator)->getCond(); 3886 break; 3887 3888 case Stmt::BinaryConditionalOperatorClass: 3889 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3890 break; 3891 3892 case Stmt::ConditionalOperatorClass: 3893 E = cast<ConditionalOperator>(Terminator)->getCond(); 3894 break; 3895 3896 case Stmt::BinaryOperatorClass: // '&&' and '||' 3897 E = cast<BinaryOperator>(Terminator)->getLHS(); 3898 break; 3899 3900 case Stmt::ObjCForCollectionStmtClass: 3901 return Terminator; 3902 } 3903 3904 return E ? E->IgnoreParens() : NULL; 3905} 3906 3907//===----------------------------------------------------------------------===// 3908// CFG Graphviz Visualization 3909//===----------------------------------------------------------------------===// 3910 3911 3912#ifndef NDEBUG 3913static StmtPrinterHelper* GraphHelper; 3914#endif 3915 3916void CFG::viewCFG(const LangOptions &LO) const { 3917#ifndef NDEBUG 3918 StmtPrinterHelper H(this, LO); 3919 GraphHelper = &H; 3920 llvm::ViewGraph(this,"CFG"); 3921 GraphHelper = NULL; 3922#endif 3923} 3924 3925namespace llvm { 3926template<> 3927struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3928 3929 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3930 3931 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 3932 3933#ifndef NDEBUG 3934 std::string OutSStr; 3935 llvm::raw_string_ostream Out(OutSStr); 3936 print_block(Out,Graph, *Node, GraphHelper, false, false); 3937 std::string& OutStr = Out.str(); 3938 3939 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3940 3941 // Process string output to make it nicer... 3942 for (unsigned i = 0; i != OutStr.length(); ++i) 3943 if (OutStr[i] == '\n') { // Left justify 3944 OutStr[i] = '\\'; 3945 OutStr.insert(OutStr.begin()+i+1, 'l'); 3946 } 3947 3948 return OutStr; 3949#else 3950 return ""; 3951#endif 3952 } 3953}; 3954} // end namespace llvm 3955