CFG.cpp revision fd8b43596478b779b6777cb3a595e69d7856c378
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/ASTContext.h" 18#include "clang/AST/DeclCXX.h" 19#include "clang/AST/StmtVisitor.h" 20#include "clang/AST/PrettyPrinter.h" 21#include "clang/AST/CharUnits.h" 22#include "clang/Basic/AttrKinds.h" 23#include "llvm/Support/GraphWriter.h" 24#include "llvm/Support/Allocator.h" 25#include "llvm/Support/Format.h" 26#include "llvm/ADT/DenseMap.h" 27#include "llvm/ADT/SmallPtrSet.h" 28#include "llvm/ADT/OwningPtr.h" 29 30using namespace clang; 31 32namespace { 33 34static SourceLocation GetEndLoc(Decl *D) { 35 if (VarDecl *VD = dyn_cast<VarDecl>(D)) 36 if (Expr *Ex = VD->getInit()) 37 return Ex->getSourceRange().getEnd(); 38 return D->getLocation(); 39} 40 41class CFGBuilder; 42 43/// The CFG builder uses a recursive algorithm to build the CFG. When 44/// we process an expression, sometimes we know that we must add the 45/// subexpressions as block-level expressions. For example: 46/// 47/// exp1 || exp2 48/// 49/// When processing the '||' expression, we know that exp1 and exp2 50/// need to be added as block-level expressions, even though they 51/// might not normally need to be. AddStmtChoice records this 52/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 53/// the builder has an option not to add a subexpression as a 54/// block-level expression. 55/// 56class AddStmtChoice { 57public: 58 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 59 60 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 61 62 bool alwaysAdd(CFGBuilder &builder, 63 const Stmt *stmt) const; 64 65 /// Return a copy of this object, except with the 'always-add' bit 66 /// set as specified. 67 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 68 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 69 } 70 71private: 72 Kind kind; 73}; 74 75/// LocalScope - Node in tree of local scopes created for C++ implicit 76/// destructor calls generation. It contains list of automatic variables 77/// declared in the scope and link to position in previous scope this scope 78/// began in. 79/// 80/// The process of creating local scopes is as follows: 81/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 82/// - Before processing statements in scope (e.g. CompoundStmt) create 83/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 84/// and set CFGBuilder::ScopePos to the end of new scope, 85/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 86/// at this VarDecl, 87/// - For every normal (without jump) end of scope add to CFGBlock destructors 88/// for objects in the current scope, 89/// - For every jump add to CFGBlock destructors for objects 90/// between CFGBuilder::ScopePos and local scope position saved for jump 91/// target. Thanks to C++ restrictions on goto jumps we can be sure that 92/// jump target position will be on the path to root from CFGBuilder::ScopePos 93/// (adding any variable that doesn't need constructor to be called to 94/// LocalScope can break this assumption), 95/// 96class LocalScope { 97public: 98 typedef BumpVector<VarDecl*> AutomaticVarsTy; 99 100 /// const_iterator - Iterates local scope backwards and jumps to previous 101 /// scope on reaching the beginning of currently iterated scope. 102 class const_iterator { 103 const LocalScope* Scope; 104 105 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 106 /// Invalid iterator (with null Scope) has VarIter equal to 0. 107 unsigned VarIter; 108 109 public: 110 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 111 /// Incrementing invalid iterator is allowed and will result in invalid 112 /// iterator. 113 const_iterator() 114 : Scope(NULL), VarIter(0) {} 115 116 /// Create valid iterator. In case when S.Prev is an invalid iterator and 117 /// I is equal to 0, this will create invalid iterator. 118 const_iterator(const LocalScope& S, unsigned I) 119 : Scope(&S), VarIter(I) { 120 // Iterator to "end" of scope is not allowed. Handle it by going up 121 // in scopes tree possibly up to invalid iterator in the root. 122 if (VarIter == 0 && Scope) 123 *this = Scope->Prev; 124 } 125 126 VarDecl *const* operator->() const { 127 assert (Scope && "Dereferencing invalid iterator is not allowed"); 128 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 129 return &Scope->Vars[VarIter - 1]; 130 } 131 VarDecl *operator*() const { 132 return *this->operator->(); 133 } 134 135 const_iterator &operator++() { 136 if (!Scope) 137 return *this; 138 139 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 140 --VarIter; 141 if (VarIter == 0) 142 *this = Scope->Prev; 143 return *this; 144 } 145 const_iterator operator++(int) { 146 const_iterator P = *this; 147 ++*this; 148 return P; 149 } 150 151 bool operator==(const const_iterator &rhs) const { 152 return Scope == rhs.Scope && VarIter == rhs.VarIter; 153 } 154 bool operator!=(const const_iterator &rhs) const { 155 return !(*this == rhs); 156 } 157 158 operator bool() const { 159 return *this != const_iterator(); 160 } 161 162 int distance(const_iterator L); 163 }; 164 165 friend class const_iterator; 166 167private: 168 BumpVectorContext ctx; 169 170 /// Automatic variables in order of declaration. 171 AutomaticVarsTy Vars; 172 /// Iterator to variable in previous scope that was declared just before 173 /// begin of this scope. 174 const_iterator Prev; 175 176public: 177 /// Constructs empty scope linked to previous scope in specified place. 178 LocalScope(BumpVectorContext &ctx, const_iterator P) 179 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 180 181 /// Begin of scope in direction of CFG building (backwards). 182 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 183 184 void addVar(VarDecl *VD) { 185 Vars.push_back(VD, ctx); 186 } 187}; 188 189/// distance - Calculates distance from this to L. L must be reachable from this 190/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 191/// number of scopes between this and L. 192int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 193 int D = 0; 194 const_iterator F = *this; 195 while (F.Scope != L.Scope) { 196 assert (F != const_iterator() 197 && "L iterator is not reachable from F iterator."); 198 D += F.VarIter; 199 F = F.Scope->Prev; 200 } 201 D += F.VarIter - L.VarIter; 202 return D; 203} 204 205/// BlockScopePosPair - Structure for specifying position in CFG during its 206/// build process. It consists of CFGBlock that specifies position in CFG graph 207/// and LocalScope::const_iterator that specifies position in LocalScope graph. 208struct BlockScopePosPair { 209 BlockScopePosPair() : block(0) {} 210 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos) 211 : block(b), scopePosition(scopePos) {} 212 213 CFGBlock *block; 214 LocalScope::const_iterator scopePosition; 215}; 216 217/// TryResult - a class representing a variant over the values 218/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 219/// and is used by the CFGBuilder to decide if a branch condition 220/// can be decided up front during CFG construction. 221class TryResult { 222 int X; 223public: 224 TryResult(bool b) : X(b ? 1 : 0) {} 225 TryResult() : X(-1) {} 226 227 bool isTrue() const { return X == 1; } 228 bool isFalse() const { return X == 0; } 229 bool isKnown() const { return X >= 0; } 230 void negate() { 231 assert(isKnown()); 232 X ^= 0x1; 233 } 234}; 235 236/// CFGBuilder - This class implements CFG construction from an AST. 237/// The builder is stateful: an instance of the builder should be used to only 238/// construct a single CFG. 239/// 240/// Example usage: 241/// 242/// CFGBuilder builder; 243/// CFG* cfg = builder.BuildAST(stmt1); 244/// 245/// CFG construction is done via a recursive walk of an AST. We actually parse 246/// the AST in reverse order so that the successor of a basic block is 247/// constructed prior to its predecessor. This allows us to nicely capture 248/// implicit fall-throughs without extra basic blocks. 249/// 250class CFGBuilder { 251 typedef BlockScopePosPair JumpTarget; 252 typedef BlockScopePosPair JumpSource; 253 254 ASTContext *Context; 255 OwningPtr<CFG> cfg; 256 257 CFGBlock *Block; 258 CFGBlock *Succ; 259 JumpTarget ContinueJumpTarget; 260 JumpTarget BreakJumpTarget; 261 CFGBlock *SwitchTerminatedBlock; 262 CFGBlock *DefaultCaseBlock; 263 CFGBlock *TryTerminatedBlock; 264 265 // Current position in local scope. 266 LocalScope::const_iterator ScopePos; 267 268 // LabelMap records the mapping from Label expressions to their jump targets. 269 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 270 LabelMapTy LabelMap; 271 272 // A list of blocks that end with a "goto" that must be backpatched to their 273 // resolved targets upon completion of CFG construction. 274 typedef std::vector<JumpSource> BackpatchBlocksTy; 275 BackpatchBlocksTy BackpatchBlocks; 276 277 // A list of labels whose address has been taken (for indirect gotos). 278 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 279 LabelSetTy AddressTakenLabels; 280 281 bool badCFG; 282 const CFG::BuildOptions &BuildOpts; 283 284 // State to track for building switch statements. 285 bool switchExclusivelyCovered; 286 Expr::EvalResult *switchCond; 287 288 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 289 const Stmt *lastLookup; 290 291 // Caches boolean evaluations of expressions to avoid multiple re-evaluations 292 // during construction of branches for chained logical operators. 293 typedef llvm::DenseMap<Expr *, TryResult> CachedBoolEvalsTy; 294 CachedBoolEvalsTy CachedBoolEvals; 295 296public: 297 explicit CFGBuilder(ASTContext *astContext, 298 const CFG::BuildOptions &buildOpts) 299 : Context(astContext), cfg(new CFG()), // crew a new CFG 300 Block(NULL), Succ(NULL), 301 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 302 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 303 switchExclusivelyCovered(false), switchCond(0), 304 cachedEntry(0), lastLookup(0) {} 305 306 // buildCFG - Used by external clients to construct the CFG. 307 CFG* buildCFG(const Decl *D, Stmt *Statement); 308 309 bool alwaysAdd(const Stmt *stmt); 310 311private: 312 // Visitors to walk an AST and construct the CFG. 313 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 314 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 315 CFGBlock *VisitBreakStmt(BreakStmt *B); 316 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 317 CFGBlock *VisitCaseStmt(CaseStmt *C); 318 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 319 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 320 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 321 AddStmtChoice asc); 322 CFGBlock *VisitContinueStmt(ContinueStmt *C); 323 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 324 AddStmtChoice asc); 325 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 326 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 327 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 328 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 329 AddStmtChoice asc); 330 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 331 AddStmtChoice asc); 332 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 333 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 334 CFGBlock *VisitDeclStmt(DeclStmt *DS); 335 CFGBlock *VisitDeclSubExpr(DeclStmt *DS); 336 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 337 CFGBlock *VisitDoStmt(DoStmt *D); 338 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc); 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 *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc); 346 CFGBlock *VisitLogicalOperator(BinaryOperator *B); 347 std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B, 348 Stmt *Term, 349 CFGBlock *TrueBlock, 350 CFGBlock *FalseBlock); 351 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 352 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 353 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 354 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 355 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 356 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S); 357 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 358 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E); 359 CFGBlock *VisitReturnStmt(ReturnStmt *R); 360 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 361 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 362 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 363 AddStmtChoice asc); 364 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 365 CFGBlock *VisitWhileStmt(WhileStmt *W); 366 367 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 368 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 369 CFGBlock *VisitChildren(Stmt *S); 370 CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc); 371 372 // Visitors to walk an AST and generate destructors of temporaries in 373 // full expression. 374 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 375 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 376 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 377 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 378 bool BindToTemporary); 379 CFGBlock * 380 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 381 bool BindToTemporary); 382 383 // NYS == Not Yet Supported 384 CFGBlock *NYS() { 385 badCFG = true; 386 return Block; 387 } 388 389 void autoCreateBlock() { if (!Block) Block = createBlock(); } 390 CFGBlock *createBlock(bool add_successor = true); 391 CFGBlock *createNoReturnBlock(); 392 393 CFGBlock *addStmt(Stmt *S) { 394 return Visit(S, AddStmtChoice::AlwaysAdd); 395 } 396 CFGBlock *addInitializer(CXXCtorInitializer *I); 397 void addAutomaticObjDtors(LocalScope::const_iterator B, 398 LocalScope::const_iterator E, Stmt *S); 399 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 400 401 // Local scopes creation. 402 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 403 404 void addLocalScopeForStmt(Stmt *S); 405 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 406 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 407 408 void addLocalScopeAndDtors(Stmt *S); 409 410 // Interface to CFGBlock - adding CFGElements. 411 void appendStmt(CFGBlock *B, const Stmt *S) { 412 if (alwaysAdd(S) && cachedEntry) 413 cachedEntry->second = B; 414 415 // All block-level expressions should have already been IgnoreParens()ed. 416 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 417 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 418 } 419 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 420 B->appendInitializer(I, cfg->getBumpVectorContext()); 421 } 422 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 423 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 424 } 425 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 426 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 427 } 428 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 429 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 430 } 431 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 432 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 433 } 434 435 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 436 LocalScope::const_iterator B, LocalScope::const_iterator E); 437 438 void addSuccessor(CFGBlock *B, CFGBlock *S) { 439 B->addSuccessor(S, cfg->getBumpVectorContext()); 440 } 441 442 /// Try and evaluate an expression to an integer constant. 443 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 444 if (!BuildOpts.PruneTriviallyFalseEdges) 445 return false; 446 return !S->isTypeDependent() && 447 !S->isValueDependent() && 448 S->EvaluateAsRValue(outResult, *Context); 449 } 450 451 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 452 /// if we can evaluate to a known value, otherwise return -1. 453 TryResult tryEvaluateBool(Expr *S) { 454 if (!BuildOpts.PruneTriviallyFalseEdges || 455 S->isTypeDependent() || S->isValueDependent()) 456 return TryResult(); 457 458 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) { 459 if (Bop->isLogicalOp()) { 460 // Check the cache first. 461 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S); 462 if (I != CachedBoolEvals.end()) 463 return I->second; // already in map; 464 465 // Retrieve result at first, or the map might be updated. 466 TryResult Result = evaluateAsBooleanConditionNoCache(S); 467 CachedBoolEvals[S] = Result; // update or insert 468 return Result; 469 } 470 } 471 472 return evaluateAsBooleanConditionNoCache(S); 473 } 474 475 /// \brief Evaluate as boolean \param E without using the cache. 476 TryResult evaluateAsBooleanConditionNoCache(Expr *E) { 477 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) { 478 if (Bop->isLogicalOp()) { 479 TryResult LHS = tryEvaluateBool(Bop->getLHS()); 480 if (LHS.isKnown()) { 481 // We were able to evaluate the LHS, see if we can get away with not 482 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1 483 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr)) 484 return LHS.isTrue(); 485 486 TryResult RHS = tryEvaluateBool(Bop->getRHS()); 487 if (RHS.isKnown()) { 488 if (Bop->getOpcode() == BO_LOr) 489 return LHS.isTrue() || RHS.isTrue(); 490 else 491 return LHS.isTrue() && RHS.isTrue(); 492 } 493 } else { 494 TryResult RHS = tryEvaluateBool(Bop->getRHS()); 495 if (RHS.isKnown()) { 496 // We can't evaluate the LHS; however, sometimes the result 497 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 498 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr)) 499 return RHS.isTrue(); 500 } 501 } 502 503 return TryResult(); 504 } 505 } 506 507 bool Result; 508 if (E->EvaluateAsBooleanCondition(Result, *Context)) 509 return Result; 510 511 return TryResult(); 512 } 513 514}; 515 516inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 517 const Stmt *stmt) const { 518 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 519} 520 521bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 522 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 523 524 if (!BuildOpts.forcedBlkExprs) 525 return shouldAdd; 526 527 if (lastLookup == stmt) { 528 if (cachedEntry) { 529 assert(cachedEntry->first == stmt); 530 return true; 531 } 532 return shouldAdd; 533 } 534 535 lastLookup = stmt; 536 537 // Perform the lookup! 538 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 539 540 if (!fb) { 541 // No need to update 'cachedEntry', since it will always be null. 542 assert(cachedEntry == 0); 543 return shouldAdd; 544 } 545 546 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 547 if (itr == fb->end()) { 548 cachedEntry = 0; 549 return shouldAdd; 550 } 551 552 cachedEntry = &*itr; 553 return true; 554} 555 556// FIXME: Add support for dependent-sized array types in C++? 557// Does it even make sense to build a CFG for an uninstantiated template? 558static const VariableArrayType *FindVA(const Type *t) { 559 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 560 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 561 if (vat->getSizeExpr()) 562 return vat; 563 564 t = vt->getElementType().getTypePtr(); 565 } 566 567 return 0; 568} 569 570/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 571/// arbitrary statement. Examples include a single expression or a function 572/// body (compound statement). The ownership of the returned CFG is 573/// transferred to the caller. If CFG construction fails, this method returns 574/// NULL. 575CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 576 assert(cfg.get()); 577 if (!Statement) 578 return NULL; 579 580 // Create an empty block that will serve as the exit block for the CFG. Since 581 // this is the first block added to the CFG, it will be implicitly registered 582 // as the exit block. 583 Succ = createBlock(); 584 assert(Succ == &cfg->getExit()); 585 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 586 587 if (BuildOpts.AddImplicitDtors) 588 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 589 addImplicitDtorsForDestructor(DD); 590 591 // Visit the statements and create the CFG. 592 CFGBlock *B = addStmt(Statement); 593 594 if (badCFG) 595 return NULL; 596 597 // For C++ constructor add initializers to CFG. 598 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 599 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 600 E = CD->init_rend(); I != E; ++I) { 601 B = addInitializer(*I); 602 if (badCFG) 603 return NULL; 604 } 605 } 606 607 if (B) 608 Succ = B; 609 610 // Backpatch the gotos whose label -> block mappings we didn't know when we 611 // encountered them. 612 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 613 E = BackpatchBlocks.end(); I != E; ++I ) { 614 615 CFGBlock *B = I->block; 616 GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 617 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 618 619 // If there is no target for the goto, then we are looking at an 620 // incomplete AST. Handle this by not registering a successor. 621 if (LI == LabelMap.end()) continue; 622 623 JumpTarget JT = LI->second; 624 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 625 JT.scopePosition); 626 addSuccessor(B, JT.block); 627 } 628 629 // Add successors to the Indirect Goto Dispatch block (if we have one). 630 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 631 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 632 E = AddressTakenLabels.end(); I != E; ++I ) { 633 634 // Lookup the target block. 635 LabelMapTy::iterator LI = LabelMap.find(*I); 636 637 // If there is no target block that contains label, then we are looking 638 // at an incomplete AST. Handle this by not registering a successor. 639 if (LI == LabelMap.end()) continue; 640 641 addSuccessor(B, LI->second.block); 642 } 643 644 // Create an empty entry block that has no predecessors. 645 cfg->setEntry(createBlock()); 646 647 return cfg.take(); 648} 649 650/// createBlock - Used to lazily create blocks that are connected 651/// to the current (global) succcessor. 652CFGBlock *CFGBuilder::createBlock(bool add_successor) { 653 CFGBlock *B = cfg->createBlock(); 654 if (add_successor && Succ) 655 addSuccessor(B, Succ); 656 return B; 657} 658 659/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the 660/// CFG. It is *not* connected to the current (global) successor, and instead 661/// directly tied to the exit block in order to be reachable. 662CFGBlock *CFGBuilder::createNoReturnBlock() { 663 CFGBlock *B = createBlock(false); 664 B->setHasNoReturnElement(); 665 addSuccessor(B, &cfg->getExit()); 666 return B; 667} 668 669/// addInitializer - Add C++ base or member initializer element to CFG. 670CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 671 if (!BuildOpts.AddInitializers) 672 return Block; 673 674 bool IsReference = false; 675 bool HasTemporaries = false; 676 677 // Destructors of temporaries in initialization expression should be called 678 // after initialization finishes. 679 Expr *Init = I->getInit(); 680 if (Init) { 681 if (FieldDecl *FD = I->getAnyMember()) 682 IsReference = FD->getType()->isReferenceType(); 683 HasTemporaries = isa<ExprWithCleanups>(Init); 684 685 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 686 // Generate destructors for temporaries in initialization expression. 687 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 688 IsReference); 689 } 690 } 691 692 autoCreateBlock(); 693 appendInitializer(Block, I); 694 695 if (Init) { 696 if (HasTemporaries) { 697 // For expression with temporaries go directly to subexpression to omit 698 // generating destructors for the second time. 699 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 700 } 701 return Visit(Init); 702 } 703 704 return Block; 705} 706 707/// \brief Retrieve the type of the temporary object whose lifetime was 708/// extended by a local reference with the given initializer. 709static QualType getReferenceInitTemporaryType(ASTContext &Context, 710 const Expr *Init) { 711 while (true) { 712 // Skip parentheses. 713 Init = Init->IgnoreParens(); 714 715 // Skip through cleanups. 716 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) { 717 Init = EWC->getSubExpr(); 718 continue; 719 } 720 721 // Skip through the temporary-materialization expression. 722 if (const MaterializeTemporaryExpr *MTE 723 = dyn_cast<MaterializeTemporaryExpr>(Init)) { 724 Init = MTE->GetTemporaryExpr(); 725 continue; 726 } 727 728 // Skip derived-to-base and no-op casts. 729 if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) { 730 if ((CE->getCastKind() == CK_DerivedToBase || 731 CE->getCastKind() == CK_UncheckedDerivedToBase || 732 CE->getCastKind() == CK_NoOp) && 733 Init->getType()->isRecordType()) { 734 Init = CE->getSubExpr(); 735 continue; 736 } 737 } 738 739 // Skip member accesses into rvalues. 740 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) { 741 if (!ME->isArrow() && ME->getBase()->isRValue()) { 742 Init = ME->getBase(); 743 continue; 744 } 745 } 746 747 break; 748 } 749 750 return Init->getType(); 751} 752 753/// addAutomaticObjDtors - Add to current block automatic objects destructors 754/// for objects in range of local scope positions. Use S as trigger statement 755/// for destructors. 756void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 757 LocalScope::const_iterator E, Stmt *S) { 758 if (!BuildOpts.AddImplicitDtors) 759 return; 760 761 if (B == E) 762 return; 763 764 // We need to append the destructors in reverse order, but any one of them 765 // may be a no-return destructor which changes the CFG. As a result, buffer 766 // this sequence up and replay them in reverse order when appending onto the 767 // CFGBlock(s). 768 SmallVector<VarDecl*, 10> Decls; 769 Decls.reserve(B.distance(E)); 770 for (LocalScope::const_iterator I = B; I != E; ++I) 771 Decls.push_back(*I); 772 773 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 774 E = Decls.rend(); 775 I != E; ++I) { 776 // If this destructor is marked as a no-return destructor, we need to 777 // create a new block for the destructor which does not have as a successor 778 // anything built thus far: control won't flow out of this block. 779 QualType Ty = (*I)->getType(); 780 if (Ty->isReferenceType()) { 781 Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit()); 782 } 783 Ty = Context->getBaseElementType(Ty); 784 785 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 786 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 787 Block = createNoReturnBlock(); 788 else 789 autoCreateBlock(); 790 791 appendAutomaticObjDtor(Block, *I, S); 792 } 793} 794 795/// addImplicitDtorsForDestructor - Add implicit destructors generated for 796/// base and member objects in destructor. 797void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 798 assert (BuildOpts.AddImplicitDtors 799 && "Can be called only when dtors should be added"); 800 const CXXRecordDecl *RD = DD->getParent(); 801 802 // At the end destroy virtual base objects. 803 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 804 VE = RD->vbases_end(); VI != VE; ++VI) { 805 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 806 if (!CD->hasTrivialDestructor()) { 807 autoCreateBlock(); 808 appendBaseDtor(Block, VI); 809 } 810 } 811 812 // Before virtual bases destroy direct base objects. 813 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 814 BE = RD->bases_end(); BI != BE; ++BI) { 815 if (!BI->isVirtual()) { 816 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 817 if (!CD->hasTrivialDestructor()) { 818 autoCreateBlock(); 819 appendBaseDtor(Block, BI); 820 } 821 } 822 } 823 824 // First destroy member objects. 825 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 826 FE = RD->field_end(); FI != FE; ++FI) { 827 // Check for constant size array. Set type to array element type. 828 QualType QT = FI->getType(); 829 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 830 if (AT->getSize() == 0) 831 continue; 832 QT = AT->getElementType(); 833 } 834 835 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 836 if (!CD->hasTrivialDestructor()) { 837 autoCreateBlock(); 838 appendMemberDtor(Block, *FI); 839 } 840 } 841} 842 843/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 844/// way return valid LocalScope object. 845LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 846 if (!Scope) { 847 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 848 Scope = alloc.Allocate<LocalScope>(); 849 BumpVectorContext ctx(alloc); 850 new (Scope) LocalScope(ctx, ScopePos); 851 } 852 return Scope; 853} 854 855/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 856/// that should create implicit scope (e.g. if/else substatements). 857void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 858 if (!BuildOpts.AddImplicitDtors) 859 return; 860 861 LocalScope *Scope = 0; 862 863 // For compound statement we will be creating explicit scope. 864 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 865 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 866 ; BI != BE; ++BI) { 867 Stmt *SI = (*BI)->stripLabelLikeStatements(); 868 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 869 Scope = addLocalScopeForDeclStmt(DS, Scope); 870 } 871 return; 872 } 873 874 // For any other statement scope will be implicit and as such will be 875 // interesting only for DeclStmt. 876 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 877 addLocalScopeForDeclStmt(DS); 878} 879 880/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 881/// reuse Scope if not NULL. 882LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 883 LocalScope* Scope) { 884 if (!BuildOpts.AddImplicitDtors) 885 return Scope; 886 887 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 888 ; DI != DE; ++DI) { 889 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 890 Scope = addLocalScopeForVarDecl(VD, Scope); 891 } 892 return Scope; 893} 894 895/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 896/// create add scope for automatic objects and temporary objects bound to 897/// const reference. Will reuse Scope if not NULL. 898LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 899 LocalScope* Scope) { 900 if (!BuildOpts.AddImplicitDtors) 901 return Scope; 902 903 // Check if variable is local. 904 switch (VD->getStorageClass()) { 905 case SC_None: 906 case SC_Auto: 907 case SC_Register: 908 break; 909 default: return Scope; 910 } 911 912 // Check for const references bound to temporary. Set type to pointee. 913 QualType QT = VD->getType(); 914 if (QT.getTypePtr()->isReferenceType()) { 915 if (!VD->extendsLifetimeOfTemporary()) 916 return Scope; 917 918 QT = getReferenceInitTemporaryType(*Context, VD->getInit()); 919 } 920 921 // Check for constant size array. Set type to array element type. 922 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 923 if (AT->getSize() == 0) 924 return Scope; 925 QT = AT->getElementType(); 926 } 927 928 // Check if type is a C++ class with non-trivial destructor. 929 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 930 if (!CD->hasTrivialDestructor()) { 931 // Add the variable to scope 932 Scope = createOrReuseLocalScope(Scope); 933 Scope->addVar(VD); 934 ScopePos = Scope->begin(); 935 } 936 return Scope; 937} 938 939/// addLocalScopeAndDtors - For given statement add local scope for it and 940/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 941void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 942 if (!BuildOpts.AddImplicitDtors) 943 return; 944 945 LocalScope::const_iterator scopeBeginPos = ScopePos; 946 addLocalScopeForStmt(S); 947 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 948} 949 950/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 951/// variables with automatic storage duration to CFGBlock's elements vector. 952/// Elements will be prepended to physical beginning of the vector which 953/// happens to be logical end. Use blocks terminator as statement that specifies 954/// destructors call site. 955/// FIXME: This mechanism for adding automatic destructors doesn't handle 956/// no-return destructors properly. 957void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 958 LocalScope::const_iterator B, LocalScope::const_iterator E) { 959 BumpVectorContext &C = cfg->getBumpVectorContext(); 960 CFGBlock::iterator InsertPos 961 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 962 for (LocalScope::const_iterator I = B; I != E; ++I) 963 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 964 Blk->getTerminator()); 965} 966 967/// Visit - Walk the subtree of a statement and add extra 968/// blocks for ternary operators, &&, and ||. We also process "," and 969/// DeclStmts (which may contain nested control-flow). 970CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 971 if (!S) { 972 badCFG = true; 973 return 0; 974 } 975 976 if (Expr *E = dyn_cast<Expr>(S)) 977 S = E->IgnoreParens(); 978 979 switch (S->getStmtClass()) { 980 default: 981 return VisitStmt(S, asc); 982 983 case Stmt::AddrLabelExprClass: 984 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 985 986 case Stmt::BinaryConditionalOperatorClass: 987 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 988 989 case Stmt::BinaryOperatorClass: 990 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 991 992 case Stmt::BlockExprClass: 993 return VisitNoRecurse(cast<Expr>(S), asc); 994 995 case Stmt::BreakStmtClass: 996 return VisitBreakStmt(cast<BreakStmt>(S)); 997 998 case Stmt::CallExprClass: 999 case Stmt::CXXOperatorCallExprClass: 1000 case Stmt::CXXMemberCallExprClass: 1001 case Stmt::UserDefinedLiteralClass: 1002 return VisitCallExpr(cast<CallExpr>(S), asc); 1003 1004 case Stmt::CaseStmtClass: 1005 return VisitCaseStmt(cast<CaseStmt>(S)); 1006 1007 case Stmt::ChooseExprClass: 1008 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 1009 1010 case Stmt::CompoundStmtClass: 1011 return VisitCompoundStmt(cast<CompoundStmt>(S)); 1012 1013 case Stmt::ConditionalOperatorClass: 1014 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 1015 1016 case Stmt::ContinueStmtClass: 1017 return VisitContinueStmt(cast<ContinueStmt>(S)); 1018 1019 case Stmt::CXXCatchStmtClass: 1020 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 1021 1022 case Stmt::ExprWithCleanupsClass: 1023 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 1024 1025 case Stmt::CXXBindTemporaryExprClass: 1026 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 1027 1028 case Stmt::CXXConstructExprClass: 1029 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 1030 1031 case Stmt::CXXFunctionalCastExprClass: 1032 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 1033 1034 case Stmt::CXXTemporaryObjectExprClass: 1035 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 1036 1037 case Stmt::CXXThrowExprClass: 1038 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 1039 1040 case Stmt::CXXTryStmtClass: 1041 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 1042 1043 case Stmt::CXXForRangeStmtClass: 1044 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 1045 1046 case Stmt::DeclStmtClass: 1047 return VisitDeclStmt(cast<DeclStmt>(S)); 1048 1049 case Stmt::DefaultStmtClass: 1050 return VisitDefaultStmt(cast<DefaultStmt>(S)); 1051 1052 case Stmt::DoStmtClass: 1053 return VisitDoStmt(cast<DoStmt>(S)); 1054 1055 case Stmt::ForStmtClass: 1056 return VisitForStmt(cast<ForStmt>(S)); 1057 1058 case Stmt::GotoStmtClass: 1059 return VisitGotoStmt(cast<GotoStmt>(S)); 1060 1061 case Stmt::IfStmtClass: 1062 return VisitIfStmt(cast<IfStmt>(S)); 1063 1064 case Stmt::ImplicitCastExprClass: 1065 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 1066 1067 case Stmt::IndirectGotoStmtClass: 1068 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 1069 1070 case Stmt::LabelStmtClass: 1071 return VisitLabelStmt(cast<LabelStmt>(S)); 1072 1073 case Stmt::LambdaExprClass: 1074 return VisitLambdaExpr(cast<LambdaExpr>(S), asc); 1075 1076 case Stmt::MemberExprClass: 1077 return VisitMemberExpr(cast<MemberExpr>(S), asc); 1078 1079 case Stmt::NullStmtClass: 1080 return Block; 1081 1082 case Stmt::ObjCAtCatchStmtClass: 1083 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 1084 1085 case Stmt::ObjCAutoreleasePoolStmtClass: 1086 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S)); 1087 1088 case Stmt::ObjCAtSynchronizedStmtClass: 1089 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 1090 1091 case Stmt::ObjCAtThrowStmtClass: 1092 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 1093 1094 case Stmt::ObjCAtTryStmtClass: 1095 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 1096 1097 case Stmt::ObjCForCollectionStmtClass: 1098 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 1099 1100 case Stmt::OpaqueValueExprClass: 1101 return Block; 1102 1103 case Stmt::PseudoObjectExprClass: 1104 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S)); 1105 1106 case Stmt::ReturnStmtClass: 1107 return VisitReturnStmt(cast<ReturnStmt>(S)); 1108 1109 case Stmt::UnaryExprOrTypeTraitExprClass: 1110 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 1111 asc); 1112 1113 case Stmt::StmtExprClass: 1114 return VisitStmtExpr(cast<StmtExpr>(S), asc); 1115 1116 case Stmt::SwitchStmtClass: 1117 return VisitSwitchStmt(cast<SwitchStmt>(S)); 1118 1119 case Stmt::UnaryOperatorClass: 1120 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 1121 1122 case Stmt::WhileStmtClass: 1123 return VisitWhileStmt(cast<WhileStmt>(S)); 1124 } 1125} 1126 1127CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1128 if (asc.alwaysAdd(*this, S)) { 1129 autoCreateBlock(); 1130 appendStmt(Block, S); 1131 } 1132 1133 return VisitChildren(S); 1134} 1135 1136/// VisitChildren - Visit the children of a Stmt. 1137CFGBlock *CFGBuilder::VisitChildren(Stmt *Terminator) { 1138 CFGBlock *lastBlock = Block; 1139 for (Stmt::child_range I = Terminator->children(); I; ++I) 1140 if (Stmt *child = *I) 1141 if (CFGBlock *b = Visit(child)) 1142 lastBlock = b; 1143 1144 return lastBlock; 1145} 1146 1147CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1148 AddStmtChoice asc) { 1149 AddressTakenLabels.insert(A->getLabel()); 1150 1151 if (asc.alwaysAdd(*this, A)) { 1152 autoCreateBlock(); 1153 appendStmt(Block, A); 1154 } 1155 1156 return Block; 1157} 1158 1159CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1160 AddStmtChoice asc) { 1161 if (asc.alwaysAdd(*this, U)) { 1162 autoCreateBlock(); 1163 appendStmt(Block, U); 1164 } 1165 1166 return Visit(U->getSubExpr(), AddStmtChoice()); 1167} 1168 1169CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) { 1170 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1171 appendStmt(ConfluenceBlock, B); 1172 1173 if (badCFG) 1174 return 0; 1175 1176 return VisitLogicalOperator(B, 0, ConfluenceBlock, ConfluenceBlock).first; 1177} 1178 1179std::pair<CFGBlock*, CFGBlock*> 1180CFGBuilder::VisitLogicalOperator(BinaryOperator *B, 1181 Stmt *Term, 1182 CFGBlock *TrueBlock, 1183 CFGBlock *FalseBlock) { 1184 1185 // Introspect the RHS. If it is a nested logical operation, we recursively 1186 // build the CFG using this function. Otherwise, resort to default 1187 // CFG construction behavior. 1188 Expr *RHS = B->getRHS()->IgnoreParens(); 1189 CFGBlock *RHSBlock, *ExitBlock; 1190 1191 do { 1192 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS)) 1193 if (B_RHS->isLogicalOp()) { 1194 llvm::tie(RHSBlock, ExitBlock) = 1195 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock); 1196 break; 1197 } 1198 1199 // The RHS is not a nested logical operation. Don't push the terminator 1200 // down further, but instead visit RHS and construct the respective 1201 // pieces of the CFG, and link up the RHSBlock with the terminator 1202 // we have been provided. 1203 ExitBlock = RHSBlock = createBlock(false); 1204 1205 if (!Term) { 1206 assert(TrueBlock == FalseBlock); 1207 addSuccessor(RHSBlock, TrueBlock); 1208 } 1209 else { 1210 RHSBlock->setTerminator(Term); 1211 TryResult KnownVal = tryEvaluateBool(RHS); 1212 addSuccessor(RHSBlock, KnownVal.isFalse() ? NULL : TrueBlock); 1213 addSuccessor(RHSBlock, KnownVal.isTrue() ? NULL : FalseBlock); 1214 } 1215 1216 Block = RHSBlock; 1217 RHSBlock = addStmt(RHS); 1218 } 1219 while (false); 1220 1221 if (badCFG) 1222 return std::make_pair((CFGBlock*)0, (CFGBlock*)0); 1223 1224 // Generate the blocks for evaluating the LHS. 1225 Expr *LHS = B->getLHS()->IgnoreParens(); 1226 1227 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS)) 1228 if (B_LHS->isLogicalOp()) { 1229 if (B->getOpcode() == BO_LOr) 1230 FalseBlock = RHSBlock; 1231 else 1232 TrueBlock = RHSBlock; 1233 1234 // For the LHS, treat 'B' as the terminator that we want to sink 1235 // into the nested branch. The RHS always gets the top-most 1236 // terminator. 1237 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock); 1238 } 1239 1240 // Create the block evaluating the LHS. 1241 // This contains the '&&' or '||' as the terminator. 1242 CFGBlock *LHSBlock = createBlock(false); 1243 LHSBlock->setTerminator(B); 1244 1245 Block = LHSBlock; 1246 CFGBlock *EntryLHSBlock = addStmt(LHS); 1247 1248 if (badCFG) 1249 return std::make_pair((CFGBlock*)0, (CFGBlock*)0); 1250 1251 // See if this is a known constant. 1252 TryResult KnownVal = tryEvaluateBool(LHS); 1253 1254 // Now link the LHSBlock with RHSBlock. 1255 if (B->getOpcode() == BO_LOr) { 1256 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : TrueBlock); 1257 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : RHSBlock); 1258 } else { 1259 assert(B->getOpcode() == BO_LAnd); 1260 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1261 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : FalseBlock); 1262 } 1263 1264 return std::make_pair(EntryLHSBlock, ExitBlock); 1265} 1266 1267 1268CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1269 AddStmtChoice asc) { 1270 // && or || 1271 if (B->isLogicalOp()) 1272 return VisitLogicalOperator(B); 1273 1274 if (B->getOpcode() == BO_Comma) { // , 1275 autoCreateBlock(); 1276 appendStmt(Block, B); 1277 addStmt(B->getRHS()); 1278 return addStmt(B->getLHS()); 1279 } 1280 1281 if (B->isAssignmentOp()) { 1282 if (asc.alwaysAdd(*this, B)) { 1283 autoCreateBlock(); 1284 appendStmt(Block, B); 1285 } 1286 Visit(B->getLHS()); 1287 return Visit(B->getRHS()); 1288 } 1289 1290 if (asc.alwaysAdd(*this, B)) { 1291 autoCreateBlock(); 1292 appendStmt(Block, B); 1293 } 1294 1295 CFGBlock *RBlock = Visit(B->getRHS()); 1296 CFGBlock *LBlock = Visit(B->getLHS()); 1297 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1298 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1299 // return RBlock. Otherwise we'll incorrectly return NULL. 1300 return (LBlock ? LBlock : RBlock); 1301} 1302 1303CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) { 1304 if (asc.alwaysAdd(*this, E)) { 1305 autoCreateBlock(); 1306 appendStmt(Block, E); 1307 } 1308 return Block; 1309} 1310 1311CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1312 // "break" is a control-flow statement. Thus we stop processing the current 1313 // block. 1314 if (badCFG) 1315 return 0; 1316 1317 // Now create a new block that ends with the break statement. 1318 Block = createBlock(false); 1319 Block->setTerminator(B); 1320 1321 // If there is no target for the break, then we are looking at an incomplete 1322 // AST. This means that the CFG cannot be constructed. 1323 if (BreakJumpTarget.block) { 1324 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1325 addSuccessor(Block, BreakJumpTarget.block); 1326 } else 1327 badCFG = true; 1328 1329 1330 return Block; 1331} 1332 1333static bool CanThrow(Expr *E, ASTContext &Ctx) { 1334 QualType Ty = E->getType(); 1335 if (Ty->isFunctionPointerType()) 1336 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1337 else if (Ty->isBlockPointerType()) 1338 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1339 1340 const FunctionType *FT = Ty->getAs<FunctionType>(); 1341 if (FT) { 1342 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1343 if (Proto->getExceptionSpecType() != EST_Uninstantiated && 1344 Proto->isNothrow(Ctx)) 1345 return false; 1346 } 1347 return true; 1348} 1349 1350CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1351 // Compute the callee type. 1352 QualType calleeType = C->getCallee()->getType(); 1353 if (calleeType == Context->BoundMemberTy) { 1354 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1355 1356 // We should only get a null bound type if processing a dependent 1357 // CFG. Recover by assuming nothing. 1358 if (!boundType.isNull()) calleeType = boundType; 1359 } 1360 1361 // If this is a call to a no-return function, this stops the block here. 1362 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1363 1364 bool AddEHEdge = false; 1365 1366 // Languages without exceptions are assumed to not throw. 1367 if (Context->getLangOpts().Exceptions) { 1368 if (BuildOpts.AddEHEdges) 1369 AddEHEdge = true; 1370 } 1371 1372 if (FunctionDecl *FD = C->getDirectCallee()) { 1373 if (FD->hasAttr<NoReturnAttr>()) 1374 NoReturn = true; 1375 if (FD->hasAttr<NoThrowAttr>()) 1376 AddEHEdge = false; 1377 } 1378 1379 if (!CanThrow(C->getCallee(), *Context)) 1380 AddEHEdge = false; 1381 1382 if (!NoReturn && !AddEHEdge) 1383 return VisitStmt(C, asc.withAlwaysAdd(true)); 1384 1385 if (Block) { 1386 Succ = Block; 1387 if (badCFG) 1388 return 0; 1389 } 1390 1391 if (NoReturn) 1392 Block = createNoReturnBlock(); 1393 else 1394 Block = createBlock(); 1395 1396 appendStmt(Block, C); 1397 1398 if (AddEHEdge) { 1399 // Add exceptional edges. 1400 if (TryTerminatedBlock) 1401 addSuccessor(Block, TryTerminatedBlock); 1402 else 1403 addSuccessor(Block, &cfg->getExit()); 1404 } 1405 1406 return VisitChildren(C); 1407} 1408 1409CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1410 AddStmtChoice asc) { 1411 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1412 appendStmt(ConfluenceBlock, C); 1413 if (badCFG) 1414 return 0; 1415 1416 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1417 Succ = ConfluenceBlock; 1418 Block = NULL; 1419 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1420 if (badCFG) 1421 return 0; 1422 1423 Succ = ConfluenceBlock; 1424 Block = NULL; 1425 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1426 if (badCFG) 1427 return 0; 1428 1429 Block = createBlock(false); 1430 // See if this is a known constant. 1431 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1432 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1433 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1434 Block->setTerminator(C); 1435 return addStmt(C->getCond()); 1436} 1437 1438 1439CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1440 addLocalScopeAndDtors(C); 1441 CFGBlock *LastBlock = Block; 1442 1443 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1444 I != E; ++I ) { 1445 // If we hit a segment of code just containing ';' (NullStmts), we can 1446 // get a null block back. In such cases, just use the LastBlock 1447 if (CFGBlock *newBlock = addStmt(*I)) 1448 LastBlock = newBlock; 1449 1450 if (badCFG) 1451 return NULL; 1452 } 1453 1454 return LastBlock; 1455} 1456 1457CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1458 AddStmtChoice asc) { 1459 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1460 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1461 1462 // Create the confluence block that will "merge" the results of the ternary 1463 // expression. 1464 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1465 appendStmt(ConfluenceBlock, C); 1466 if (badCFG) 1467 return 0; 1468 1469 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1470 1471 // Create a block for the LHS expression if there is an LHS expression. A 1472 // GCC extension allows LHS to be NULL, causing the condition to be the 1473 // value that is returned instead. 1474 // e.g: x ?: y is shorthand for: x ? x : y; 1475 Succ = ConfluenceBlock; 1476 Block = NULL; 1477 CFGBlock *LHSBlock = 0; 1478 const Expr *trueExpr = C->getTrueExpr(); 1479 if (trueExpr != opaqueValue) { 1480 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1481 if (badCFG) 1482 return 0; 1483 Block = NULL; 1484 } 1485 else 1486 LHSBlock = ConfluenceBlock; 1487 1488 // Create the block for the RHS expression. 1489 Succ = ConfluenceBlock; 1490 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1491 if (badCFG) 1492 return 0; 1493 1494 // Create the block that will contain the condition. 1495 Block = createBlock(false); 1496 1497 // See if this is a known constant. 1498 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1499 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1500 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1501 Block->setTerminator(C); 1502 Expr *condExpr = C->getCond(); 1503 1504 if (opaqueValue) { 1505 // Run the condition expression if it's not trivially expressed in 1506 // terms of the opaque value (or if there is no opaque value). 1507 if (condExpr != opaqueValue) 1508 addStmt(condExpr); 1509 1510 // Before that, run the common subexpression if there was one. 1511 // At least one of this or the above will be run. 1512 return addStmt(BCO->getCommon()); 1513 } 1514 1515 return addStmt(condExpr); 1516} 1517 1518CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1519 // Check if the Decl is for an __label__. If so, elide it from the 1520 // CFG entirely. 1521 if (isa<LabelDecl>(*DS->decl_begin())) 1522 return Block; 1523 1524 // This case also handles static_asserts. 1525 if (DS->isSingleDecl()) 1526 return VisitDeclSubExpr(DS); 1527 1528 CFGBlock *B = 0; 1529 1530 // Build an individual DeclStmt for each decl. 1531 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(), 1532 E = DS->decl_rend(); 1533 I != E; ++I) { 1534 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1535 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1536 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1537 1538 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1539 // automatically freed with the CFG. 1540 DeclGroupRef DG(*I); 1541 Decl *D = *I; 1542 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1543 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1544 1545 // Append the fake DeclStmt to block. 1546 B = VisitDeclSubExpr(DSNew); 1547 } 1548 1549 return B; 1550} 1551 1552/// VisitDeclSubExpr - Utility method to add block-level expressions for 1553/// DeclStmts and initializers in them. 1554CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1555 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1556 Decl *D = DS->getSingleDecl(); 1557 1558 if (isa<StaticAssertDecl>(D)) { 1559 // static_asserts aren't added to the CFG because they do not impact 1560 // runtime semantics. 1561 return Block; 1562 } 1563 1564 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1565 1566 if (!VD) { 1567 autoCreateBlock(); 1568 appendStmt(Block, DS); 1569 return Block; 1570 } 1571 1572 bool IsReference = false; 1573 bool HasTemporaries = false; 1574 1575 // Destructors of temporaries in initialization expression should be called 1576 // after initialization finishes. 1577 Expr *Init = VD->getInit(); 1578 if (Init) { 1579 IsReference = VD->getType()->isReferenceType(); 1580 HasTemporaries = isa<ExprWithCleanups>(Init); 1581 1582 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1583 // Generate destructors for temporaries in initialization expression. 1584 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1585 IsReference); 1586 } 1587 } 1588 1589 autoCreateBlock(); 1590 appendStmt(Block, DS); 1591 1592 // Keep track of the last non-null block, as 'Block' can be nulled out 1593 // if the initializer expression is something like a 'while' in a 1594 // statement-expression. 1595 CFGBlock *LastBlock = Block; 1596 1597 if (Init) { 1598 if (HasTemporaries) { 1599 // For expression with temporaries go directly to subexpression to omit 1600 // generating destructors for the second time. 1601 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init); 1602 if (CFGBlock *newBlock = Visit(EC->getSubExpr())) 1603 LastBlock = newBlock; 1604 } 1605 else { 1606 if (CFGBlock *newBlock = Visit(Init)) 1607 LastBlock = newBlock; 1608 } 1609 } 1610 1611 // If the type of VD is a VLA, then we must process its size expressions. 1612 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1613 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1614 Block = addStmt(VA->getSizeExpr()); 1615 1616 // Remove variable from local scope. 1617 if (ScopePos && VD == *ScopePos) 1618 ++ScopePos; 1619 1620 return Block ? Block : LastBlock; 1621} 1622 1623CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1624 // We may see an if statement in the middle of a basic block, or it may be the 1625 // first statement we are processing. In either case, we create a new basic 1626 // block. First, we create the blocks for the then...else statements, and 1627 // then we create the block containing the if statement. If we were in the 1628 // middle of a block, we stop processing that block. That block is then the 1629 // implicit successor for the "then" and "else" clauses. 1630 1631 // Save local scope position because in case of condition variable ScopePos 1632 // won't be restored when traversing AST. 1633 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1634 1635 // Create local scope for possible condition variable. 1636 // Store scope position. Add implicit destructor. 1637 if (VarDecl *VD = I->getConditionVariable()) { 1638 LocalScope::const_iterator BeginScopePos = ScopePos; 1639 addLocalScopeForVarDecl(VD); 1640 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1641 } 1642 1643 // The block we were processing is now finished. Make it the successor 1644 // block. 1645 if (Block) { 1646 Succ = Block; 1647 if (badCFG) 1648 return 0; 1649 } 1650 1651 // Process the false branch. 1652 CFGBlock *ElseBlock = Succ; 1653 1654 if (Stmt *Else = I->getElse()) { 1655 SaveAndRestore<CFGBlock*> sv(Succ); 1656 1657 // NULL out Block so that the recursive call to Visit will 1658 // create a new basic block. 1659 Block = NULL; 1660 1661 // If branch is not a compound statement create implicit scope 1662 // and add destructors. 1663 if (!isa<CompoundStmt>(Else)) 1664 addLocalScopeAndDtors(Else); 1665 1666 ElseBlock = addStmt(Else); 1667 1668 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1669 ElseBlock = sv.get(); 1670 else if (Block) { 1671 if (badCFG) 1672 return 0; 1673 } 1674 } 1675 1676 // Process the true branch. 1677 CFGBlock *ThenBlock; 1678 { 1679 Stmt *Then = I->getThen(); 1680 assert(Then); 1681 SaveAndRestore<CFGBlock*> sv(Succ); 1682 Block = NULL; 1683 1684 // If branch is not a compound statement create implicit scope 1685 // and add destructors. 1686 if (!isa<CompoundStmt>(Then)) 1687 addLocalScopeAndDtors(Then); 1688 1689 ThenBlock = addStmt(Then); 1690 1691 if (!ThenBlock) { 1692 // We can reach here if the "then" body has all NullStmts. 1693 // Create an empty block so we can distinguish between true and false 1694 // branches in path-sensitive analyses. 1695 ThenBlock = createBlock(false); 1696 addSuccessor(ThenBlock, sv.get()); 1697 } else if (Block) { 1698 if (badCFG) 1699 return 0; 1700 } 1701 } 1702 1703 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by 1704 // having these handle the actual control-flow jump. Note that 1705 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)" 1706 // we resort to the old control-flow behavior. This special handling 1707 // removes infeasible paths from the control-flow graph by having the 1708 // control-flow transfer of '&&' or '||' go directly into the then/else 1709 // blocks directly. 1710 if (!I->getConditionVariable()) 1711 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(I->getCond())) 1712 if (Cond->isLogicalOp()) 1713 return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first; 1714 1715 // Now create a new block containing the if statement. 1716 Block = createBlock(false); 1717 1718 // Set the terminator of the new block to the If statement. 1719 Block->setTerminator(I); 1720 1721 // See if this is a known constant. 1722 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1723 1724 // Now add the successors. 1725 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1726 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1727 1728 // Add the condition as the last statement in the new block. This may create 1729 // new blocks as the condition may contain control-flow. Any newly created 1730 // blocks will be pointed to be "Block". 1731 Block = addStmt(I->getCond()); 1732 1733 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1734 // and the condition variable initialization to the CFG. 1735 if (VarDecl *VD = I->getConditionVariable()) { 1736 if (Expr *Init = VD->getInit()) { 1737 autoCreateBlock(); 1738 appendStmt(Block, I->getConditionVariableDeclStmt()); 1739 addStmt(Init); 1740 } 1741 } 1742 1743 return Block; 1744} 1745 1746 1747CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1748 // If we were in the middle of a block we stop processing that block. 1749 // 1750 // NOTE: If a "return" appears in the middle of a block, this means that the 1751 // code afterwards is DEAD (unreachable). We still keep a basic block 1752 // for that code; a simple "mark-and-sweep" from the entry block will be 1753 // able to report such dead blocks. 1754 1755 // Create the new block. 1756 Block = createBlock(false); 1757 1758 // The Exit block is the only successor. 1759 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1760 addSuccessor(Block, &cfg->getExit()); 1761 1762 // Add the return statement to the block. This may create new blocks if R 1763 // contains control-flow (short-circuit operations). 1764 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1765} 1766 1767CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1768 // Get the block of the labeled statement. Add it to our map. 1769 addStmt(L->getSubStmt()); 1770 CFGBlock *LabelBlock = Block; 1771 1772 if (!LabelBlock) // This can happen when the body is empty, i.e. 1773 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1774 1775 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1776 "label already in map"); 1777 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1778 1779 // Labels partition blocks, so this is the end of the basic block we were 1780 // processing (L is the block's label). Because this is label (and we have 1781 // already processed the substatement) there is no extra control-flow to worry 1782 // about. 1783 LabelBlock->setLabel(L); 1784 if (badCFG) 1785 return 0; 1786 1787 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1788 Block = NULL; 1789 1790 // This block is now the implicit successor of other blocks. 1791 Succ = LabelBlock; 1792 1793 return LabelBlock; 1794} 1795 1796CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) { 1797 CFGBlock *LastBlock = VisitNoRecurse(E, asc); 1798 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(), 1799 et = E->capture_init_end(); it != et; ++it) { 1800 if (Expr *Init = *it) { 1801 CFGBlock *Tmp = Visit(Init); 1802 if (Tmp != 0) 1803 LastBlock = Tmp; 1804 } 1805 } 1806 return LastBlock; 1807} 1808 1809CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1810 // Goto is a control-flow statement. Thus we stop processing the current 1811 // block and create a new one. 1812 1813 Block = createBlock(false); 1814 Block->setTerminator(G); 1815 1816 // If we already know the mapping to the label block add the successor now. 1817 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1818 1819 if (I == LabelMap.end()) 1820 // We will need to backpatch this block later. 1821 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1822 else { 1823 JumpTarget JT = I->second; 1824 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1825 addSuccessor(Block, JT.block); 1826 } 1827 1828 return Block; 1829} 1830 1831CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1832 CFGBlock *LoopSuccessor = NULL; 1833 1834 // Save local scope position because in case of condition variable ScopePos 1835 // won't be restored when traversing AST. 1836 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1837 1838 // Create local scope for init statement and possible condition variable. 1839 // Add destructor for init statement and condition variable. 1840 // Store scope position for continue statement. 1841 if (Stmt *Init = F->getInit()) 1842 addLocalScopeForStmt(Init); 1843 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1844 1845 if (VarDecl *VD = F->getConditionVariable()) 1846 addLocalScopeForVarDecl(VD); 1847 LocalScope::const_iterator ContinueScopePos = ScopePos; 1848 1849 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1850 1851 // "for" is a control-flow statement. Thus we stop processing the current 1852 // block. 1853 if (Block) { 1854 if (badCFG) 1855 return 0; 1856 LoopSuccessor = Block; 1857 } else 1858 LoopSuccessor = Succ; 1859 1860 // Save the current value for the break targets. 1861 // All breaks should go to the code following the loop. 1862 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1863 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1864 1865 CFGBlock *BodyBlock = 0, *TransitionBlock = 0; 1866 1867 // Now create the loop body. 1868 { 1869 assert(F->getBody()); 1870 1871 // Save the current values for Block, Succ, continue and break targets. 1872 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1873 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1874 1875 // Create an empty block to represent the transition block for looping back 1876 // to the head of the loop. If we have increment code, it will 1877 // go in this block as well. 1878 Block = Succ = TransitionBlock = createBlock(false); 1879 TransitionBlock->setLoopTarget(F); 1880 1881 if (Stmt *I = F->getInc()) { 1882 // Generate increment code in its own basic block. This is the target of 1883 // continue statements. 1884 Succ = addStmt(I); 1885 } 1886 1887 // Finish up the increment (or empty) block if it hasn't been already. 1888 if (Block) { 1889 assert(Block == Succ); 1890 if (badCFG) 1891 return 0; 1892 Block = 0; 1893 } 1894 1895 // The starting block for the loop increment is the block that should 1896 // represent the 'loop target' for looping back to the start of the loop. 1897 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1898 ContinueJumpTarget.block->setLoopTarget(F); 1899 1900 // Loop body should end with destructor of Condition variable (if any). 1901 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1902 1903 // If body is not a compound statement create implicit scope 1904 // and add destructors. 1905 if (!isa<CompoundStmt>(F->getBody())) 1906 addLocalScopeAndDtors(F->getBody()); 1907 1908 // Now populate the body block, and in the process create new blocks as we 1909 // walk the body of the loop. 1910 BodyBlock = addStmt(F->getBody()); 1911 1912 if (!BodyBlock) { 1913 // In the case of "for (...;...;...);" we can have a null BodyBlock. 1914 // Use the continue jump target as the proxy for the body. 1915 BodyBlock = ContinueJumpTarget.block; 1916 } 1917 else if (badCFG) 1918 return 0; 1919 } 1920 1921 // Because of short-circuit evaluation, the condition of the loop can span 1922 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1923 // evaluate the condition. 1924 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0; 1925 1926 do { 1927 Expr *C = F->getCond(); 1928 1929 // Specially handle logical operators, which have a slightly 1930 // more optimal CFG representation. 1931 if (BinaryOperator *Cond = dyn_cast_or_null<BinaryOperator>(C)) 1932 if (Cond->isLogicalOp()) { 1933 llvm::tie(EntryConditionBlock, ExitConditionBlock) = 1934 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor); 1935 break; 1936 } 1937 1938 // The default case when not handling logical operators. 1939 EntryConditionBlock = ExitConditionBlock = createBlock(false); 1940 ExitConditionBlock->setTerminator(F); 1941 1942 // See if this is a known constant. 1943 TryResult KnownVal(true); 1944 1945 if (C) { 1946 // Now add the actual condition to the condition block. 1947 // Because the condition itself may contain control-flow, new blocks may 1948 // be created. Thus we update "Succ" after adding the condition. 1949 Block = ExitConditionBlock; 1950 EntryConditionBlock = addStmt(C); 1951 1952 // If this block contains a condition variable, add both the condition 1953 // variable and initializer to the CFG. 1954 if (VarDecl *VD = F->getConditionVariable()) { 1955 if (Expr *Init = VD->getInit()) { 1956 autoCreateBlock(); 1957 appendStmt(Block, F->getConditionVariableDeclStmt()); 1958 EntryConditionBlock = addStmt(Init); 1959 assert(Block == EntryConditionBlock); 1960 } 1961 } 1962 1963 if (Block && badCFG) 1964 return 0; 1965 1966 KnownVal = tryEvaluateBool(C); 1967 } 1968 1969 // Add the loop body entry as a successor to the condition. 1970 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1971 // Link up the condition block with the code that follows the loop. (the 1972 // false branch). 1973 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1974 1975 } while (false); 1976 1977 // Link up the loop-back block to the entry condition block. 1978 addSuccessor(TransitionBlock, EntryConditionBlock); 1979 1980 // The condition block is the implicit successor for any code above the loop. 1981 Succ = EntryConditionBlock; 1982 1983 // If the loop contains initialization, create a new block for those 1984 // statements. This block can also contain statements that precede the loop. 1985 if (Stmt *I = F->getInit()) { 1986 Block = createBlock(); 1987 return addStmt(I); 1988 } 1989 1990 // There is no loop initialization. We are thus basically a while loop. 1991 // NULL out Block to force lazy block construction. 1992 Block = NULL; 1993 Succ = EntryConditionBlock; 1994 return EntryConditionBlock; 1995} 1996 1997CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1998 if (asc.alwaysAdd(*this, M)) { 1999 autoCreateBlock(); 2000 appendStmt(Block, M); 2001 } 2002 return Visit(M->getBase()); 2003} 2004 2005CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 2006 // Objective-C fast enumeration 'for' statements: 2007 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 2008 // 2009 // for ( Type newVariable in collection_expression ) { statements } 2010 // 2011 // becomes: 2012 // 2013 // prologue: 2014 // 1. collection_expression 2015 // T. jump to loop_entry 2016 // loop_entry: 2017 // 1. side-effects of element expression 2018 // 1. ObjCForCollectionStmt [performs binding to newVariable] 2019 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 2020 // TB: 2021 // statements 2022 // T. jump to loop_entry 2023 // FB: 2024 // what comes after 2025 // 2026 // and 2027 // 2028 // Type existingItem; 2029 // for ( existingItem in expression ) { statements } 2030 // 2031 // becomes: 2032 // 2033 // the same with newVariable replaced with existingItem; the binding works 2034 // the same except that for one ObjCForCollectionStmt::getElement() returns 2035 // a DeclStmt and the other returns a DeclRefExpr. 2036 // 2037 2038 CFGBlock *LoopSuccessor = 0; 2039 2040 if (Block) { 2041 if (badCFG) 2042 return 0; 2043 LoopSuccessor = Block; 2044 Block = 0; 2045 } else 2046 LoopSuccessor = Succ; 2047 2048 // Build the condition blocks. 2049 CFGBlock *ExitConditionBlock = createBlock(false); 2050 2051 // Set the terminator for the "exit" condition block. 2052 ExitConditionBlock->setTerminator(S); 2053 2054 // The last statement in the block should be the ObjCForCollectionStmt, which 2055 // performs the actual binding to 'element' and determines if there are any 2056 // more items in the collection. 2057 appendStmt(ExitConditionBlock, S); 2058 Block = ExitConditionBlock; 2059 2060 // Walk the 'element' expression to see if there are any side-effects. We 2061 // generate new blocks as necessary. We DON'T add the statement by default to 2062 // the CFG unless it contains control-flow. 2063 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 2064 AddStmtChoice::NotAlwaysAdd); 2065 if (Block) { 2066 if (badCFG) 2067 return 0; 2068 Block = 0; 2069 } 2070 2071 // The condition block is the implicit successor for the loop body as well as 2072 // any code above the loop. 2073 Succ = EntryConditionBlock; 2074 2075 // Now create the true branch. 2076 { 2077 // Save the current values for Succ, continue and break targets. 2078 SaveAndRestore<CFGBlock*> save_Succ(Succ); 2079 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2080 save_break(BreakJumpTarget); 2081 2082 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2083 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2084 2085 CFGBlock *BodyBlock = addStmt(S->getBody()); 2086 2087 if (!BodyBlock) 2088 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 2089 else if (Block) { 2090 if (badCFG) 2091 return 0; 2092 } 2093 2094 // This new body block is a successor to our "exit" condition block. 2095 addSuccessor(ExitConditionBlock, BodyBlock); 2096 } 2097 2098 // Link up the condition block with the code that follows the loop. 2099 // (the false branch). 2100 addSuccessor(ExitConditionBlock, LoopSuccessor); 2101 2102 // Now create a prologue block to contain the collection expression. 2103 Block = createBlock(); 2104 return addStmt(S->getCollection()); 2105} 2106 2107CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) { 2108 // Inline the body. 2109 return addStmt(S->getSubStmt()); 2110 // TODO: consider adding cleanups for the end of @autoreleasepool scope. 2111} 2112 2113CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 2114 // FIXME: Add locking 'primitives' to CFG for @synchronized. 2115 2116 // Inline the body. 2117 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 2118 2119 // The sync body starts its own basic block. This makes it a little easier 2120 // for diagnostic clients. 2121 if (SyncBlock) { 2122 if (badCFG) 2123 return 0; 2124 2125 Block = 0; 2126 Succ = SyncBlock; 2127 } 2128 2129 // Add the @synchronized to the CFG. 2130 autoCreateBlock(); 2131 appendStmt(Block, S); 2132 2133 // Inline the sync expression. 2134 return addStmt(S->getSynchExpr()); 2135} 2136 2137CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 2138 // FIXME 2139 return NYS(); 2140} 2141 2142CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) { 2143 autoCreateBlock(); 2144 2145 // Add the PseudoObject as the last thing. 2146 appendStmt(Block, E); 2147 2148 CFGBlock *lastBlock = Block; 2149 2150 // Before that, evaluate all of the semantics in order. In 2151 // CFG-land, that means appending them in reverse order. 2152 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) { 2153 Expr *Semantic = E->getSemanticExpr(--i); 2154 2155 // If the semantic is an opaque value, we're being asked to bind 2156 // it to its source expression. 2157 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic)) 2158 Semantic = OVE->getSourceExpr(); 2159 2160 if (CFGBlock *B = Visit(Semantic)) 2161 lastBlock = B; 2162 } 2163 2164 return lastBlock; 2165} 2166 2167CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 2168 CFGBlock *LoopSuccessor = NULL; 2169 2170 // Save local scope position because in case of condition variable ScopePos 2171 // won't be restored when traversing AST. 2172 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2173 2174 // Create local scope for possible condition variable. 2175 // Store scope position for continue statement. 2176 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 2177 if (VarDecl *VD = W->getConditionVariable()) { 2178 addLocalScopeForVarDecl(VD); 2179 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2180 } 2181 2182 // "while" is a control-flow statement. Thus we stop processing the current 2183 // block. 2184 if (Block) { 2185 if (badCFG) 2186 return 0; 2187 LoopSuccessor = Block; 2188 Block = 0; 2189 } else { 2190 LoopSuccessor = Succ; 2191 } 2192 2193 CFGBlock *BodyBlock = 0, *TransitionBlock = 0; 2194 2195 // Process the loop body. 2196 { 2197 assert(W->getBody()); 2198 2199 // Save the current values for Block, Succ, continue and break targets. 2200 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2201 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2202 save_break(BreakJumpTarget); 2203 2204 // Create an empty block to represent the transition block for looping back 2205 // to the head of the loop. 2206 Succ = TransitionBlock = createBlock(false); 2207 TransitionBlock->setLoopTarget(W); 2208 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 2209 2210 // All breaks should go to the code following the loop. 2211 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2212 2213 // Loop body should end with destructor of Condition variable (if any). 2214 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2215 2216 // If body is not a compound statement create implicit scope 2217 // and add destructors. 2218 if (!isa<CompoundStmt>(W->getBody())) 2219 addLocalScopeAndDtors(W->getBody()); 2220 2221 // Create the body. The returned block is the entry to the loop body. 2222 BodyBlock = addStmt(W->getBody()); 2223 2224 if (!BodyBlock) 2225 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2226 else if (Block && badCFG) 2227 return 0; 2228 } 2229 2230 // Because of short-circuit evaluation, the condition of the loop can span 2231 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2232 // evaluate the condition. 2233 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0; 2234 2235 do { 2236 Expr *C = W->getCond(); 2237 2238 // Specially handle logical operators, which have a slightly 2239 // more optimal CFG representation. 2240 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C)) 2241 if (Cond->isLogicalOp()) { 2242 llvm::tie(EntryConditionBlock, ExitConditionBlock) = 2243 VisitLogicalOperator(Cond, W, BodyBlock, 2244 LoopSuccessor); 2245 break; 2246 } 2247 2248 // The default case when not handling logical operators. 2249 EntryConditionBlock = ExitConditionBlock = createBlock(false); 2250 ExitConditionBlock->setTerminator(W); 2251 2252 // Now add the actual condition to the condition block. 2253 // Because the condition itself may contain control-flow, new blocks may 2254 // be created. Thus we update "Succ" after adding the condition. 2255 Block = ExitConditionBlock; 2256 Block = EntryConditionBlock = addStmt(C); 2257 2258 // If this block contains a condition variable, add both the condition 2259 // variable and initializer to the CFG. 2260 if (VarDecl *VD = W->getConditionVariable()) { 2261 if (Expr *Init = VD->getInit()) { 2262 autoCreateBlock(); 2263 appendStmt(Block, W->getConditionVariableDeclStmt()); 2264 EntryConditionBlock = addStmt(Init); 2265 assert(Block == EntryConditionBlock); 2266 } 2267 } 2268 2269 if (Block && badCFG) 2270 return 0; 2271 2272 // See if this is a known constant. 2273 const TryResult& KnownVal = tryEvaluateBool(C); 2274 2275 // Add the loop body entry as a successor to the condition. 2276 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2277 // Link up the condition block with the code that follows the loop. (the 2278 // false branch). 2279 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2280 2281 } while(false); 2282 2283 // Link up the loop-back block to the entry condition block. 2284 addSuccessor(TransitionBlock, EntryConditionBlock); 2285 2286 // There can be no more statements in the condition block since we loop back 2287 // to this block. NULL out Block to force lazy creation of another block. 2288 Block = NULL; 2289 2290 // Return the condition block, which is the dominating block for the loop. 2291 Succ = EntryConditionBlock; 2292 return EntryConditionBlock; 2293} 2294 2295 2296CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2297 // FIXME: For now we pretend that @catch and the code it contains does not 2298 // exit. 2299 return Block; 2300} 2301 2302CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2303 // FIXME: This isn't complete. We basically treat @throw like a return 2304 // statement. 2305 2306 // If we were in the middle of a block we stop processing that block. 2307 if (badCFG) 2308 return 0; 2309 2310 // Create the new block. 2311 Block = createBlock(false); 2312 2313 // The Exit block is the only successor. 2314 addSuccessor(Block, &cfg->getExit()); 2315 2316 // Add the statement to the block. This may create new blocks if S contains 2317 // control-flow (short-circuit operations). 2318 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2319} 2320 2321CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2322 // If we were in the middle of a block we stop processing that block. 2323 if (badCFG) 2324 return 0; 2325 2326 // Create the new block. 2327 Block = createBlock(false); 2328 2329 if (TryTerminatedBlock) 2330 // The current try statement is the only successor. 2331 addSuccessor(Block, TryTerminatedBlock); 2332 else 2333 // otherwise the Exit block is the only successor. 2334 addSuccessor(Block, &cfg->getExit()); 2335 2336 // Add the statement to the block. This may create new blocks if S contains 2337 // control-flow (short-circuit operations). 2338 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2339} 2340 2341CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2342 CFGBlock *LoopSuccessor = NULL; 2343 2344 // "do...while" is a control-flow statement. Thus we stop processing the 2345 // current block. 2346 if (Block) { 2347 if (badCFG) 2348 return 0; 2349 LoopSuccessor = Block; 2350 } else 2351 LoopSuccessor = Succ; 2352 2353 // Because of short-circuit evaluation, the condition of the loop can span 2354 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2355 // evaluate the condition. 2356 CFGBlock *ExitConditionBlock = createBlock(false); 2357 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2358 2359 // Set the terminator for the "exit" condition block. 2360 ExitConditionBlock->setTerminator(D); 2361 2362 // Now add the actual condition to the condition block. Because the condition 2363 // itself may contain control-flow, new blocks may be created. 2364 if (Stmt *C = D->getCond()) { 2365 Block = ExitConditionBlock; 2366 EntryConditionBlock = addStmt(C); 2367 if (Block) { 2368 if (badCFG) 2369 return 0; 2370 } 2371 } 2372 2373 // The condition block is the implicit successor for the loop body. 2374 Succ = EntryConditionBlock; 2375 2376 // See if this is a known constant. 2377 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2378 2379 // Process the loop body. 2380 CFGBlock *BodyBlock = NULL; 2381 { 2382 assert(D->getBody()); 2383 2384 // Save the current values for Block, Succ, and continue and break targets 2385 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2386 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2387 save_break(BreakJumpTarget); 2388 2389 // All continues within this loop should go to the condition block 2390 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2391 2392 // All breaks should go to the code following the loop. 2393 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2394 2395 // NULL out Block to force lazy instantiation of blocks for the body. 2396 Block = NULL; 2397 2398 // If body is not a compound statement create implicit scope 2399 // and add destructors. 2400 if (!isa<CompoundStmt>(D->getBody())) 2401 addLocalScopeAndDtors(D->getBody()); 2402 2403 // Create the body. The returned block is the entry to the loop body. 2404 BodyBlock = addStmt(D->getBody()); 2405 2406 if (!BodyBlock) 2407 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2408 else if (Block) { 2409 if (badCFG) 2410 return 0; 2411 } 2412 2413 if (!KnownVal.isFalse()) { 2414 // Add an intermediate block between the BodyBlock and the 2415 // ExitConditionBlock to represent the "loop back" transition. Create an 2416 // empty block to represent the transition block for looping back to the 2417 // head of the loop. 2418 // FIXME: Can we do this more efficiently without adding another block? 2419 Block = NULL; 2420 Succ = BodyBlock; 2421 CFGBlock *LoopBackBlock = createBlock(); 2422 LoopBackBlock->setLoopTarget(D); 2423 2424 // Add the loop body entry as a successor to the condition. 2425 addSuccessor(ExitConditionBlock, LoopBackBlock); 2426 } 2427 else 2428 addSuccessor(ExitConditionBlock, NULL); 2429 } 2430 2431 // Link up the condition block with the code that follows the loop. 2432 // (the false branch). 2433 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2434 2435 // There can be no more statements in the body block(s) since we loop back to 2436 // the body. NULL out Block to force lazy creation of another block. 2437 Block = NULL; 2438 2439 // Return the loop body, which is the dominating block for the loop. 2440 Succ = BodyBlock; 2441 return BodyBlock; 2442} 2443 2444CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2445 // "continue" is a control-flow statement. Thus we stop processing the 2446 // current block. 2447 if (badCFG) 2448 return 0; 2449 2450 // Now create a new block that ends with the continue statement. 2451 Block = createBlock(false); 2452 Block->setTerminator(C); 2453 2454 // If there is no target for the continue, then we are looking at an 2455 // incomplete AST. This means the CFG cannot be constructed. 2456 if (ContinueJumpTarget.block) { 2457 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2458 addSuccessor(Block, ContinueJumpTarget.block); 2459 } else 2460 badCFG = true; 2461 2462 return Block; 2463} 2464 2465CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2466 AddStmtChoice asc) { 2467 2468 if (asc.alwaysAdd(*this, E)) { 2469 autoCreateBlock(); 2470 appendStmt(Block, E); 2471 } 2472 2473 // VLA types have expressions that must be evaluated. 2474 CFGBlock *lastBlock = Block; 2475 2476 if (E->isArgumentType()) { 2477 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2478 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2479 lastBlock = addStmt(VA->getSizeExpr()); 2480 } 2481 return lastBlock; 2482} 2483 2484/// VisitStmtExpr - Utility method to handle (nested) statement 2485/// expressions (a GCC extension). 2486CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2487 if (asc.alwaysAdd(*this, SE)) { 2488 autoCreateBlock(); 2489 appendStmt(Block, SE); 2490 } 2491 return VisitCompoundStmt(SE->getSubStmt()); 2492} 2493 2494CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2495 // "switch" is a control-flow statement. Thus we stop processing the current 2496 // block. 2497 CFGBlock *SwitchSuccessor = NULL; 2498 2499 // Save local scope position because in case of condition variable ScopePos 2500 // won't be restored when traversing AST. 2501 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2502 2503 // Create local scope for possible condition variable. 2504 // Store scope position. Add implicit destructor. 2505 if (VarDecl *VD = Terminator->getConditionVariable()) { 2506 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2507 addLocalScopeForVarDecl(VD); 2508 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2509 } 2510 2511 if (Block) { 2512 if (badCFG) 2513 return 0; 2514 SwitchSuccessor = Block; 2515 } else SwitchSuccessor = Succ; 2516 2517 // Save the current "switch" context. 2518 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2519 save_default(DefaultCaseBlock); 2520 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2521 2522 // Set the "default" case to be the block after the switch statement. If the 2523 // switch statement contains a "default:", this value will be overwritten with 2524 // the block for that code. 2525 DefaultCaseBlock = SwitchSuccessor; 2526 2527 // Create a new block that will contain the switch statement. 2528 SwitchTerminatedBlock = createBlock(false); 2529 2530 // Now process the switch body. The code after the switch is the implicit 2531 // successor. 2532 Succ = SwitchSuccessor; 2533 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2534 2535 // When visiting the body, the case statements should automatically get linked 2536 // up to the switch. We also don't keep a pointer to the body, since all 2537 // control-flow from the switch goes to case/default statements. 2538 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2539 Block = NULL; 2540 2541 // For pruning unreachable case statements, save the current state 2542 // for tracking the condition value. 2543 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2544 false); 2545 2546 // Determine if the switch condition can be explicitly evaluated. 2547 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2548 Expr::EvalResult result; 2549 bool b = tryEvaluate(Terminator->getCond(), result); 2550 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2551 b ? &result : 0); 2552 2553 // If body is not a compound statement create implicit scope 2554 // and add destructors. 2555 if (!isa<CompoundStmt>(Terminator->getBody())) 2556 addLocalScopeAndDtors(Terminator->getBody()); 2557 2558 addStmt(Terminator->getBody()); 2559 if (Block) { 2560 if (badCFG) 2561 return 0; 2562 } 2563 2564 // If we have no "default:" case, the default transition is to the code 2565 // following the switch body. Moreover, take into account if all the 2566 // cases of a switch are covered (e.g., switching on an enum value). 2567 addSuccessor(SwitchTerminatedBlock, 2568 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2569 ? 0 : DefaultCaseBlock); 2570 2571 // Add the terminator and condition in the switch block. 2572 SwitchTerminatedBlock->setTerminator(Terminator); 2573 Block = SwitchTerminatedBlock; 2574 Block = addStmt(Terminator->getCond()); 2575 2576 // Finally, if the SwitchStmt contains a condition variable, add both the 2577 // SwitchStmt and the condition variable initialization to the CFG. 2578 if (VarDecl *VD = Terminator->getConditionVariable()) { 2579 if (Expr *Init = VD->getInit()) { 2580 autoCreateBlock(); 2581 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2582 addStmt(Init); 2583 } 2584 } 2585 2586 return Block; 2587} 2588 2589static bool shouldAddCase(bool &switchExclusivelyCovered, 2590 const Expr::EvalResult *switchCond, 2591 const CaseStmt *CS, 2592 ASTContext &Ctx) { 2593 if (!switchCond) 2594 return true; 2595 2596 bool addCase = false; 2597 2598 if (!switchExclusivelyCovered) { 2599 if (switchCond->Val.isInt()) { 2600 // Evaluate the LHS of the case value. 2601 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2602 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2603 2604 if (condInt == lhsInt) { 2605 addCase = true; 2606 switchExclusivelyCovered = true; 2607 } 2608 else if (condInt < lhsInt) { 2609 if (const Expr *RHS = CS->getRHS()) { 2610 // Evaluate the RHS of the case value. 2611 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2612 if (V2 <= condInt) { 2613 addCase = true; 2614 switchExclusivelyCovered = true; 2615 } 2616 } 2617 } 2618 } 2619 else 2620 addCase = true; 2621 } 2622 return addCase; 2623} 2624 2625CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2626 // CaseStmts are essentially labels, so they are the first statement in a 2627 // block. 2628 CFGBlock *TopBlock = 0, *LastBlock = 0; 2629 2630 if (Stmt *Sub = CS->getSubStmt()) { 2631 // For deeply nested chains of CaseStmts, instead of doing a recursion 2632 // (which can blow out the stack), manually unroll and create blocks 2633 // along the way. 2634 while (isa<CaseStmt>(Sub)) { 2635 CFGBlock *currentBlock = createBlock(false); 2636 currentBlock->setLabel(CS); 2637 2638 if (TopBlock) 2639 addSuccessor(LastBlock, currentBlock); 2640 else 2641 TopBlock = currentBlock; 2642 2643 addSuccessor(SwitchTerminatedBlock, 2644 shouldAddCase(switchExclusivelyCovered, switchCond, 2645 CS, *Context) 2646 ? currentBlock : 0); 2647 2648 LastBlock = currentBlock; 2649 CS = cast<CaseStmt>(Sub); 2650 Sub = CS->getSubStmt(); 2651 } 2652 2653 addStmt(Sub); 2654 } 2655 2656 CFGBlock *CaseBlock = Block; 2657 if (!CaseBlock) 2658 CaseBlock = createBlock(); 2659 2660 // Cases statements partition blocks, so this is the top of the basic block we 2661 // were processing (the "case XXX:" is the label). 2662 CaseBlock->setLabel(CS); 2663 2664 if (badCFG) 2665 return 0; 2666 2667 // Add this block to the list of successors for the block with the switch 2668 // statement. 2669 assert(SwitchTerminatedBlock); 2670 addSuccessor(SwitchTerminatedBlock, 2671 shouldAddCase(switchExclusivelyCovered, switchCond, 2672 CS, *Context) 2673 ? CaseBlock : 0); 2674 2675 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2676 Block = NULL; 2677 2678 if (TopBlock) { 2679 addSuccessor(LastBlock, CaseBlock); 2680 Succ = TopBlock; 2681 } else { 2682 // This block is now the implicit successor of other blocks. 2683 Succ = CaseBlock; 2684 } 2685 2686 return Succ; 2687} 2688 2689CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2690 if (Terminator->getSubStmt()) 2691 addStmt(Terminator->getSubStmt()); 2692 2693 DefaultCaseBlock = Block; 2694 2695 if (!DefaultCaseBlock) 2696 DefaultCaseBlock = createBlock(); 2697 2698 // Default statements partition blocks, so this is the top of the basic block 2699 // we were processing (the "default:" is the label). 2700 DefaultCaseBlock->setLabel(Terminator); 2701 2702 if (badCFG) 2703 return 0; 2704 2705 // Unlike case statements, we don't add the default block to the successors 2706 // for the switch statement immediately. This is done when we finish 2707 // processing the switch statement. This allows for the default case 2708 // (including a fall-through to the code after the switch statement) to always 2709 // be the last successor of a switch-terminated block. 2710 2711 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2712 Block = NULL; 2713 2714 // This block is now the implicit successor of other blocks. 2715 Succ = DefaultCaseBlock; 2716 2717 return DefaultCaseBlock; 2718} 2719 2720CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2721 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2722 // current block. 2723 CFGBlock *TrySuccessor = NULL; 2724 2725 if (Block) { 2726 if (badCFG) 2727 return 0; 2728 TrySuccessor = Block; 2729 } else TrySuccessor = Succ; 2730 2731 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2732 2733 // Create a new block that will contain the try statement. 2734 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2735 // Add the terminator in the try block. 2736 NewTryTerminatedBlock->setTerminator(Terminator); 2737 2738 bool HasCatchAll = false; 2739 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2740 // The code after the try is the implicit successor. 2741 Succ = TrySuccessor; 2742 CXXCatchStmt *CS = Terminator->getHandler(h); 2743 if (CS->getExceptionDecl() == 0) { 2744 HasCatchAll = true; 2745 } 2746 Block = NULL; 2747 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2748 if (CatchBlock == 0) 2749 return 0; 2750 // Add this block to the list of successors for the block with the try 2751 // statement. 2752 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2753 } 2754 if (!HasCatchAll) { 2755 if (PrevTryTerminatedBlock) 2756 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2757 else 2758 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2759 } 2760 2761 // The code after the try is the implicit successor. 2762 Succ = TrySuccessor; 2763 2764 // Save the current "try" context. 2765 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2766 cfg->addTryDispatchBlock(TryTerminatedBlock); 2767 2768 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2769 Block = NULL; 2770 Block = addStmt(Terminator->getTryBlock()); 2771 return Block; 2772} 2773 2774CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2775 // CXXCatchStmt are treated like labels, so they are the first statement in a 2776 // block. 2777 2778 // Save local scope position because in case of exception variable ScopePos 2779 // won't be restored when traversing AST. 2780 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2781 2782 // Create local scope for possible exception variable. 2783 // Store scope position. Add implicit destructor. 2784 if (VarDecl *VD = CS->getExceptionDecl()) { 2785 LocalScope::const_iterator BeginScopePos = ScopePos; 2786 addLocalScopeForVarDecl(VD); 2787 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2788 } 2789 2790 if (CS->getHandlerBlock()) 2791 addStmt(CS->getHandlerBlock()); 2792 2793 CFGBlock *CatchBlock = Block; 2794 if (!CatchBlock) 2795 CatchBlock = createBlock(); 2796 2797 // CXXCatchStmt is more than just a label. They have semantic meaning 2798 // as well, as they implicitly "initialize" the catch variable. Add 2799 // it to the CFG as a CFGElement so that the control-flow of these 2800 // semantics gets captured. 2801 appendStmt(CatchBlock, CS); 2802 2803 // Also add the CXXCatchStmt as a label, to mirror handling of regular 2804 // labels. 2805 CatchBlock->setLabel(CS); 2806 2807 // Bail out if the CFG is bad. 2808 if (badCFG) 2809 return 0; 2810 2811 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2812 Block = NULL; 2813 2814 return CatchBlock; 2815} 2816 2817CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2818 // C++0x for-range statements are specified as [stmt.ranged]: 2819 // 2820 // { 2821 // auto && __range = range-init; 2822 // for ( auto __begin = begin-expr, 2823 // __end = end-expr; 2824 // __begin != __end; 2825 // ++__begin ) { 2826 // for-range-declaration = *__begin; 2827 // statement 2828 // } 2829 // } 2830 2831 // Save local scope position before the addition of the implicit variables. 2832 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2833 2834 // Create local scopes and destructors for range, begin and end variables. 2835 if (Stmt *Range = S->getRangeStmt()) 2836 addLocalScopeForStmt(Range); 2837 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2838 addLocalScopeForStmt(BeginEnd); 2839 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2840 2841 LocalScope::const_iterator ContinueScopePos = ScopePos; 2842 2843 // "for" is a control-flow statement. Thus we stop processing the current 2844 // block. 2845 CFGBlock *LoopSuccessor = NULL; 2846 if (Block) { 2847 if (badCFG) 2848 return 0; 2849 LoopSuccessor = Block; 2850 } else 2851 LoopSuccessor = Succ; 2852 2853 // Save the current value for the break targets. 2854 // All breaks should go to the code following the loop. 2855 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2856 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2857 2858 // The block for the __begin != __end expression. 2859 CFGBlock *ConditionBlock = createBlock(false); 2860 ConditionBlock->setTerminator(S); 2861 2862 // Now add the actual condition to the condition block. 2863 if (Expr *C = S->getCond()) { 2864 Block = ConditionBlock; 2865 CFGBlock *BeginConditionBlock = addStmt(C); 2866 if (badCFG) 2867 return 0; 2868 assert(BeginConditionBlock == ConditionBlock && 2869 "condition block in for-range was unexpectedly complex"); 2870 (void)BeginConditionBlock; 2871 } 2872 2873 // The condition block is the implicit successor for the loop body as well as 2874 // any code above the loop. 2875 Succ = ConditionBlock; 2876 2877 // See if this is a known constant. 2878 TryResult KnownVal(true); 2879 2880 if (S->getCond()) 2881 KnownVal = tryEvaluateBool(S->getCond()); 2882 2883 // Now create the loop body. 2884 { 2885 assert(S->getBody()); 2886 2887 // Save the current values for Block, Succ, and continue targets. 2888 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2889 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2890 2891 // Generate increment code in its own basic block. This is the target of 2892 // continue statements. 2893 Block = 0; 2894 Succ = addStmt(S->getInc()); 2895 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2896 2897 // The starting block for the loop increment is the block that should 2898 // represent the 'loop target' for looping back to the start of the loop. 2899 ContinueJumpTarget.block->setLoopTarget(S); 2900 2901 // Finish up the increment block and prepare to start the loop body. 2902 assert(Block); 2903 if (badCFG) 2904 return 0; 2905 Block = 0; 2906 2907 2908 // Add implicit scope and dtors for loop variable. 2909 addLocalScopeAndDtors(S->getLoopVarStmt()); 2910 2911 // Populate a new block to contain the loop body and loop variable. 2912 Block = addStmt(S->getBody()); 2913 if (badCFG) 2914 return 0; 2915 Block = addStmt(S->getLoopVarStmt()); 2916 if (badCFG) 2917 return 0; 2918 2919 // This new body block is a successor to our condition block. 2920 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2921 } 2922 2923 // Link up the condition block with the code that follows the loop (the 2924 // false branch). 2925 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2926 2927 // Add the initialization statements. 2928 Block = createBlock(); 2929 addStmt(S->getBeginEndStmt()); 2930 return addStmt(S->getRangeStmt()); 2931} 2932 2933CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2934 AddStmtChoice asc) { 2935 if (BuildOpts.AddImplicitDtors) { 2936 // If adding implicit destructors visit the full expression for adding 2937 // destructors of temporaries. 2938 VisitForTemporaryDtors(E->getSubExpr()); 2939 2940 // Full expression has to be added as CFGStmt so it will be sequenced 2941 // before destructors of it's temporaries. 2942 asc = asc.withAlwaysAdd(true); 2943 } 2944 return Visit(E->getSubExpr(), asc); 2945} 2946 2947CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2948 AddStmtChoice asc) { 2949 if (asc.alwaysAdd(*this, E)) { 2950 autoCreateBlock(); 2951 appendStmt(Block, E); 2952 2953 // We do not want to propagate the AlwaysAdd property. 2954 asc = asc.withAlwaysAdd(false); 2955 } 2956 return Visit(E->getSubExpr(), asc); 2957} 2958 2959CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2960 AddStmtChoice asc) { 2961 autoCreateBlock(); 2962 appendStmt(Block, C); 2963 2964 return VisitChildren(C); 2965} 2966 2967CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2968 AddStmtChoice asc) { 2969 if (asc.alwaysAdd(*this, E)) { 2970 autoCreateBlock(); 2971 appendStmt(Block, E); 2972 // We do not want to propagate the AlwaysAdd property. 2973 asc = asc.withAlwaysAdd(false); 2974 } 2975 return Visit(E->getSubExpr(), asc); 2976} 2977 2978CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2979 AddStmtChoice asc) { 2980 autoCreateBlock(); 2981 appendStmt(Block, C); 2982 return VisitChildren(C); 2983} 2984 2985CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2986 AddStmtChoice asc) { 2987 if (asc.alwaysAdd(*this, E)) { 2988 autoCreateBlock(); 2989 appendStmt(Block, E); 2990 } 2991 return Visit(E->getSubExpr(), AddStmtChoice()); 2992} 2993 2994CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 2995 // Lazily create the indirect-goto dispatch block if there isn't one already. 2996 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 2997 2998 if (!IBlock) { 2999 IBlock = createBlock(false); 3000 cfg->setIndirectGotoBlock(IBlock); 3001 } 3002 3003 // IndirectGoto is a control-flow statement. Thus we stop processing the 3004 // current block and create a new one. 3005 if (badCFG) 3006 return 0; 3007 3008 Block = createBlock(false); 3009 Block->setTerminator(I); 3010 addSuccessor(Block, IBlock); 3011 return addStmt(I->getTarget()); 3012} 3013 3014CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 3015tryAgain: 3016 if (!E) { 3017 badCFG = true; 3018 return NULL; 3019 } 3020 switch (E->getStmtClass()) { 3021 default: 3022 return VisitChildrenForTemporaryDtors(E); 3023 3024 case Stmt::BinaryOperatorClass: 3025 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 3026 3027 case Stmt::CXXBindTemporaryExprClass: 3028 return VisitCXXBindTemporaryExprForTemporaryDtors( 3029 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 3030 3031 case Stmt::BinaryConditionalOperatorClass: 3032 case Stmt::ConditionalOperatorClass: 3033 return VisitConditionalOperatorForTemporaryDtors( 3034 cast<AbstractConditionalOperator>(E), BindToTemporary); 3035 3036 case Stmt::ImplicitCastExprClass: 3037 // For implicit cast we want BindToTemporary to be passed further. 3038 E = cast<CastExpr>(E)->getSubExpr(); 3039 goto tryAgain; 3040 3041 case Stmt::ParenExprClass: 3042 E = cast<ParenExpr>(E)->getSubExpr(); 3043 goto tryAgain; 3044 3045 case Stmt::MaterializeTemporaryExprClass: 3046 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 3047 goto tryAgain; 3048 } 3049} 3050 3051CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 3052 // When visiting children for destructors we want to visit them in reverse 3053 // order. Because there's no reverse iterator for children must to reverse 3054 // them in helper vector. 3055 typedef SmallVector<Stmt *, 4> ChildrenVect; 3056 ChildrenVect ChildrenRev; 3057 for (Stmt::child_range I = E->children(); I; ++I) { 3058 if (*I) ChildrenRev.push_back(*I); 3059 } 3060 3061 CFGBlock *B = Block; 3062 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 3063 L = ChildrenRev.rend(); I != L; ++I) { 3064 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 3065 B = R; 3066 } 3067 return B; 3068} 3069 3070CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 3071 if (E->isLogicalOp()) { 3072 // Destructors for temporaries in LHS expression should be called after 3073 // those for RHS expression. Even if this will unnecessarily create a block, 3074 // this block will be used at least by the full expression. 3075 autoCreateBlock(); 3076 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 3077 if (badCFG) 3078 return NULL; 3079 3080 Succ = ConfluenceBlock; 3081 Block = NULL; 3082 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3083 3084 if (RHSBlock) { 3085 if (badCFG) 3086 return NULL; 3087 3088 // If RHS expression did produce destructors we need to connect created 3089 // blocks to CFG in same manner as for binary operator itself. 3090 CFGBlock *LHSBlock = createBlock(false); 3091 LHSBlock->setTerminator(CFGTerminator(E, true)); 3092 3093 // For binary operator LHS block is before RHS in list of predecessors 3094 // of ConfluenceBlock. 3095 std::reverse(ConfluenceBlock->pred_begin(), 3096 ConfluenceBlock->pred_end()); 3097 3098 // See if this is a known constant. 3099 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 3100 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 3101 KnownVal.negate(); 3102 3103 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 3104 // itself. 3105 if (E->getOpcode() == BO_LOr) { 3106 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3107 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3108 } else { 3109 assert (E->getOpcode() == BO_LAnd); 3110 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3111 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3112 } 3113 3114 Block = LHSBlock; 3115 return LHSBlock; 3116 } 3117 3118 Block = ConfluenceBlock; 3119 return ConfluenceBlock; 3120 } 3121 3122 if (E->isAssignmentOp()) { 3123 // For assignment operator (=) LHS expression is visited 3124 // before RHS expression. For destructors visit them in reverse order. 3125 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3126 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3127 return LHSBlock ? LHSBlock : RHSBlock; 3128 } 3129 3130 // For any other binary operator RHS expression is visited before 3131 // LHS expression (order of children). For destructors visit them in reverse 3132 // order. 3133 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3134 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3135 return RHSBlock ? RHSBlock : LHSBlock; 3136} 3137 3138CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 3139 CXXBindTemporaryExpr *E, bool BindToTemporary) { 3140 // First add destructors for temporaries in subexpression. 3141 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 3142 if (!BindToTemporary) { 3143 // If lifetime of temporary is not prolonged (by assigning to constant 3144 // reference) add destructor for it. 3145 3146 // If the destructor is marked as a no-return destructor, we need to create 3147 // a new block for the destructor which does not have as a successor 3148 // anything built thus far. Control won't flow out of this block. 3149 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 3150 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 3151 Block = createNoReturnBlock(); 3152 else 3153 autoCreateBlock(); 3154 3155 appendTemporaryDtor(Block, E); 3156 B = Block; 3157 } 3158 return B; 3159} 3160 3161CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 3162 AbstractConditionalOperator *E, bool BindToTemporary) { 3163 // First add destructors for condition expression. Even if this will 3164 // unnecessarily create a block, this block will be used at least by the full 3165 // expression. 3166 autoCreateBlock(); 3167 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 3168 if (badCFG) 3169 return NULL; 3170 if (BinaryConditionalOperator *BCO 3171 = dyn_cast<BinaryConditionalOperator>(E)) { 3172 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 3173 if (badCFG) 3174 return NULL; 3175 } 3176 3177 // Try to add block with destructors for LHS expression. 3178 CFGBlock *LHSBlock = NULL; 3179 Succ = ConfluenceBlock; 3180 Block = NULL; 3181 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 3182 if (badCFG) 3183 return NULL; 3184 3185 // Try to add block with destructors for RHS expression; 3186 Succ = ConfluenceBlock; 3187 Block = NULL; 3188 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 3189 BindToTemporary); 3190 if (badCFG) 3191 return NULL; 3192 3193 if (!RHSBlock && !LHSBlock) { 3194 // If neither LHS nor RHS expression had temporaries to destroy don't create 3195 // more blocks. 3196 Block = ConfluenceBlock; 3197 return Block; 3198 } 3199 3200 Block = createBlock(false); 3201 Block->setTerminator(CFGTerminator(E, true)); 3202 3203 // See if this is a known constant. 3204 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 3205 3206 if (LHSBlock) { 3207 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 3208 } else if (KnownVal.isFalse()) { 3209 addSuccessor(Block, NULL); 3210 } else { 3211 addSuccessor(Block, ConfluenceBlock); 3212 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 3213 } 3214 3215 if (!RHSBlock) 3216 RHSBlock = ConfluenceBlock; 3217 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 3218 3219 return Block; 3220} 3221 3222} // end anonymous namespace 3223 3224/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 3225/// no successors or predecessors. If this is the first block created in the 3226/// CFG, it is automatically set to be the Entry and Exit of the CFG. 3227CFGBlock *CFG::createBlock() { 3228 bool first_block = begin() == end(); 3229 3230 // Create the block. 3231 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 3232 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this); 3233 Blocks.push_back(Mem, BlkBVC); 3234 3235 // If this is the first block, set it as the Entry and Exit. 3236 if (first_block) 3237 Entry = Exit = &back(); 3238 3239 // Return the block. 3240 return &back(); 3241} 3242 3243/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 3244/// CFG is returned to the caller. 3245CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 3246 const BuildOptions &BO) { 3247 CFGBuilder Builder(C, BO); 3248 return Builder.buildCFG(D, Statement); 3249} 3250 3251const CXXDestructorDecl * 3252CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 3253 switch (getKind()) { 3254 case CFGElement::Invalid: 3255 case CFGElement::Statement: 3256 case CFGElement::Initializer: 3257 llvm_unreachable("getDestructorDecl should only be used with " 3258 "ImplicitDtors"); 3259 case CFGElement::AutomaticObjectDtor: { 3260 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 3261 QualType ty = var->getType(); 3262 ty = ty.getNonReferenceType(); 3263 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3264 ty = arrayType->getElementType(); 3265 } 3266 const RecordType *recordType = ty->getAs<RecordType>(); 3267 const CXXRecordDecl *classDecl = 3268 cast<CXXRecordDecl>(recordType->getDecl()); 3269 return classDecl->getDestructor(); 3270 } 3271 case CFGElement::TemporaryDtor: { 3272 const CXXBindTemporaryExpr *bindExpr = 3273 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 3274 const CXXTemporary *temp = bindExpr->getTemporary(); 3275 return temp->getDestructor(); 3276 } 3277 case CFGElement::BaseDtor: 3278 case CFGElement::MemberDtor: 3279 3280 // Not yet supported. 3281 return 0; 3282 } 3283 llvm_unreachable("getKind() returned bogus value"); 3284} 3285 3286bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3287 if (const CXXDestructorDecl *decl = getDestructorDecl(astContext)) { 3288 QualType ty = decl->getType(); 3289 return cast<FunctionType>(ty)->getNoReturnAttr(); 3290 } 3291 return false; 3292} 3293 3294//===----------------------------------------------------------------------===// 3295// CFG: Queries for BlkExprs. 3296//===----------------------------------------------------------------------===// 3297 3298namespace { 3299 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3300} 3301 3302static void FindSubExprAssignments(const Stmt *S, 3303 llvm::SmallPtrSet<const Expr*,50>& Set) { 3304 if (!S) 3305 return; 3306 3307 for (Stmt::const_child_range I = S->children(); I; ++I) { 3308 const Stmt *child = *I; 3309 if (!child) 3310 continue; 3311 3312 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3313 if (B->isAssignmentOp()) Set.insert(B); 3314 3315 FindSubExprAssignments(child, Set); 3316 } 3317} 3318 3319static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3320 BlkExprMapTy* M = new BlkExprMapTy(); 3321 3322 // Look for assignments that are used as subexpressions. These are the only 3323 // assignments that we want to *possibly* register as a block-level 3324 // expression. Basically, if an assignment occurs both in a subexpression and 3325 // at the block-level, it is a block-level expression. 3326 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3327 3328 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3329 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3330 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3331 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3332 3333 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3334 3335 // Iterate over the statements again on identify the Expr* and Stmt* at the 3336 // block-level that are block-level expressions. 3337 3338 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3339 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3340 if (!CS) 3341 continue; 3342 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3343 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3344 3345 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3346 // Assignment expressions that are not nested within another 3347 // expression are really "statements" whose value is never used by 3348 // another expression. 3349 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3350 continue; 3351 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3352 // Special handling for statement expressions. The last statement in 3353 // the statement expression is also a block-level expr. 3354 const CompoundStmt *C = SE->getSubStmt(); 3355 if (!C->body_empty()) { 3356 const Stmt *Last = C->body_back(); 3357 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3358 Last = LastEx->IgnoreParens(); 3359 unsigned x = M->size(); 3360 (*M)[Last] = x; 3361 } 3362 } 3363 3364 unsigned x = M->size(); 3365 (*M)[Exp] = x; 3366 } 3367 } 3368 3369 // Look at terminators. The condition is a block-level expression. 3370 3371 Stmt *S = (*I)->getTerminatorCondition(); 3372 3373 if (S && M->find(S) == M->end()) { 3374 unsigned x = M->size(); 3375 (*M)[S] = x; 3376 } 3377 } 3378 3379 return M; 3380} 3381 3382CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3383 assert(S != NULL); 3384 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3385 3386 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3387 BlkExprMapTy::iterator I = M->find(S); 3388 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3389} 3390 3391unsigned CFG::getNumBlkExprs() { 3392 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3393 return M->size(); 3394 3395 // We assume callers interested in the number of BlkExprs will want 3396 // the map constructed if it doesn't already exist. 3397 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3398 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3399} 3400 3401//===----------------------------------------------------------------------===// 3402// Filtered walking of the CFG. 3403//===----------------------------------------------------------------------===// 3404 3405bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3406 const CFGBlock *From, const CFGBlock *To) { 3407 3408 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3409 // If the 'To' has no label or is labeled but the label isn't a 3410 // CaseStmt then filter this edge. 3411 if (const SwitchStmt *S = 3412 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3413 if (S->isAllEnumCasesCovered()) { 3414 const Stmt *L = To->getLabel(); 3415 if (!L || !isa<CaseStmt>(L)) 3416 return true; 3417 } 3418 } 3419 } 3420 3421 return false; 3422} 3423 3424//===----------------------------------------------------------------------===// 3425// Cleanup: CFG dstor. 3426//===----------------------------------------------------------------------===// 3427 3428CFG::~CFG() { 3429 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3430} 3431 3432//===----------------------------------------------------------------------===// 3433// CFG pretty printing 3434//===----------------------------------------------------------------------===// 3435 3436namespace { 3437 3438class StmtPrinterHelper : public PrinterHelper { 3439 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3440 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3441 StmtMapTy StmtMap; 3442 DeclMapTy DeclMap; 3443 signed currentBlock; 3444 unsigned currentStmt; 3445 const LangOptions &LangOpts; 3446public: 3447 3448 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3449 : currentBlock(0), currentStmt(0), LangOpts(LO) 3450 { 3451 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3452 unsigned j = 1; 3453 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3454 BI != BEnd; ++BI, ++j ) { 3455 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3456 const Stmt *stmt= SE->getStmt(); 3457 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3458 StmtMap[stmt] = P; 3459 3460 switch (stmt->getStmtClass()) { 3461 case Stmt::DeclStmtClass: 3462 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3463 break; 3464 case Stmt::IfStmtClass: { 3465 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3466 if (var) 3467 DeclMap[var] = P; 3468 break; 3469 } 3470 case Stmt::ForStmtClass: { 3471 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3472 if (var) 3473 DeclMap[var] = P; 3474 break; 3475 } 3476 case Stmt::WhileStmtClass: { 3477 const VarDecl *var = 3478 cast<WhileStmt>(stmt)->getConditionVariable(); 3479 if (var) 3480 DeclMap[var] = P; 3481 break; 3482 } 3483 case Stmt::SwitchStmtClass: { 3484 const VarDecl *var = 3485 cast<SwitchStmt>(stmt)->getConditionVariable(); 3486 if (var) 3487 DeclMap[var] = P; 3488 break; 3489 } 3490 case Stmt::CXXCatchStmtClass: { 3491 const VarDecl *var = 3492 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3493 if (var) 3494 DeclMap[var] = P; 3495 break; 3496 } 3497 default: 3498 break; 3499 } 3500 } 3501 } 3502 } 3503 } 3504 3505 3506 virtual ~StmtPrinterHelper() {} 3507 3508 const LangOptions &getLangOpts() const { return LangOpts; } 3509 void setBlockID(signed i) { currentBlock = i; } 3510 void setStmtID(unsigned i) { currentStmt = i; } 3511 3512 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3513 StmtMapTy::iterator I = StmtMap.find(S); 3514 3515 if (I == StmtMap.end()) 3516 return false; 3517 3518 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3519 && I->second.second == currentStmt) { 3520 return false; 3521 } 3522 3523 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3524 return true; 3525 } 3526 3527 bool handleDecl(const Decl *D, raw_ostream &OS) { 3528 DeclMapTy::iterator I = DeclMap.find(D); 3529 3530 if (I == DeclMap.end()) 3531 return false; 3532 3533 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3534 && I->second.second == currentStmt) { 3535 return false; 3536 } 3537 3538 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3539 return true; 3540 } 3541}; 3542} // end anonymous namespace 3543 3544 3545namespace { 3546class CFGBlockTerminatorPrint 3547 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3548 3549 raw_ostream &OS; 3550 StmtPrinterHelper* Helper; 3551 PrintingPolicy Policy; 3552public: 3553 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3554 const PrintingPolicy &Policy) 3555 : OS(os), Helper(helper), Policy(Policy) {} 3556 3557 void VisitIfStmt(IfStmt *I) { 3558 OS << "if "; 3559 I->getCond()->printPretty(OS,Helper,Policy); 3560 } 3561 3562 // Default case. 3563 void VisitStmt(Stmt *Terminator) { 3564 Terminator->printPretty(OS, Helper, Policy); 3565 } 3566 3567 void VisitForStmt(ForStmt *F) { 3568 OS << "for (" ; 3569 if (F->getInit()) 3570 OS << "..."; 3571 OS << "; "; 3572 if (Stmt *C = F->getCond()) 3573 C->printPretty(OS, Helper, Policy); 3574 OS << "; "; 3575 if (F->getInc()) 3576 OS << "..."; 3577 OS << ")"; 3578 } 3579 3580 void VisitWhileStmt(WhileStmt *W) { 3581 OS << "while " ; 3582 if (Stmt *C = W->getCond()) 3583 C->printPretty(OS, Helper, Policy); 3584 } 3585 3586 void VisitDoStmt(DoStmt *D) { 3587 OS << "do ... while "; 3588 if (Stmt *C = D->getCond()) 3589 C->printPretty(OS, Helper, Policy); 3590 } 3591 3592 void VisitSwitchStmt(SwitchStmt *Terminator) { 3593 OS << "switch "; 3594 Terminator->getCond()->printPretty(OS, Helper, Policy); 3595 } 3596 3597 void VisitCXXTryStmt(CXXTryStmt *CS) { 3598 OS << "try ..."; 3599 } 3600 3601 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3602 C->getCond()->printPretty(OS, Helper, Policy); 3603 OS << " ? ... : ..."; 3604 } 3605 3606 void VisitChooseExpr(ChooseExpr *C) { 3607 OS << "__builtin_choose_expr( "; 3608 C->getCond()->printPretty(OS, Helper, Policy); 3609 OS << " )"; 3610 } 3611 3612 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3613 OS << "goto *"; 3614 I->getTarget()->printPretty(OS, Helper, Policy); 3615 } 3616 3617 void VisitBinaryOperator(BinaryOperator* B) { 3618 if (!B->isLogicalOp()) { 3619 VisitExpr(B); 3620 return; 3621 } 3622 3623 B->getLHS()->printPretty(OS, Helper, Policy); 3624 3625 switch (B->getOpcode()) { 3626 case BO_LOr: 3627 OS << " || ..."; 3628 return; 3629 case BO_LAnd: 3630 OS << " && ..."; 3631 return; 3632 default: 3633 llvm_unreachable("Invalid logical operator."); 3634 } 3635 } 3636 3637 void VisitExpr(Expr *E) { 3638 E->printPretty(OS, Helper, Policy); 3639 } 3640}; 3641} // end anonymous namespace 3642 3643static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3644 const CFGElement &E) { 3645 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3646 const Stmt *S = CS->getStmt(); 3647 3648 if (Helper) { 3649 3650 // special printing for statement-expressions. 3651 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3652 const CompoundStmt *Sub = SE->getSubStmt(); 3653 3654 if (Sub->children()) { 3655 OS << "({ ... ; "; 3656 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3657 OS << " })\n"; 3658 return; 3659 } 3660 } 3661 // special printing for comma expressions. 3662 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3663 if (B->getOpcode() == BO_Comma) { 3664 OS << "... , "; 3665 Helper->handledStmt(B->getRHS(),OS); 3666 OS << '\n'; 3667 return; 3668 } 3669 } 3670 } 3671 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3672 3673 if (isa<CXXOperatorCallExpr>(S)) { 3674 OS << " (OperatorCall)"; 3675 } 3676 else if (isa<CXXBindTemporaryExpr>(S)) { 3677 OS << " (BindTemporary)"; 3678 } 3679 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) { 3680 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")"; 3681 } 3682 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) { 3683 OS << " (" << CE->getStmtClassName() << ", " 3684 << CE->getCastKindName() 3685 << ", " << CE->getType().getAsString() 3686 << ")"; 3687 } 3688 3689 // Expressions need a newline. 3690 if (isa<Expr>(S)) 3691 OS << '\n'; 3692 3693 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3694 const CXXCtorInitializer *I = IE->getInitializer(); 3695 if (I->isBaseInitializer()) 3696 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3697 else OS << I->getAnyMember()->getName(); 3698 3699 OS << "("; 3700 if (Expr *IE = I->getInit()) 3701 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3702 OS << ")"; 3703 3704 if (I->isBaseInitializer()) 3705 OS << " (Base initializer)\n"; 3706 else OS << " (Member initializer)\n"; 3707 3708 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3709 const VarDecl *VD = DE->getVarDecl(); 3710 Helper->handleDecl(VD, OS); 3711 3712 const Type* T = VD->getType().getTypePtr(); 3713 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3714 T = RT->getPointeeType().getTypePtr(); 3715 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3716 T = ET; 3717 3718 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3719 OS << " (Implicit destructor)\n"; 3720 3721 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3722 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3723 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3724 OS << " (Base object destructor)\n"; 3725 3726 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3727 const FieldDecl *FD = ME->getFieldDecl(); 3728 3729 const Type *T = FD->getType().getTypePtr(); 3730 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3731 T = ET; 3732 3733 OS << "this->" << FD->getName(); 3734 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3735 OS << " (Member object destructor)\n"; 3736 3737 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3738 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3739 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3740 OS << " (Temporary object destructor)\n"; 3741 } 3742} 3743 3744static void print_block(raw_ostream &OS, const CFG* cfg, 3745 const CFGBlock &B, 3746 StmtPrinterHelper* Helper, bool print_edges, 3747 bool ShowColors) { 3748 3749 if (Helper) 3750 Helper->setBlockID(B.getBlockID()); 3751 3752 // Print the header. 3753 if (ShowColors) 3754 OS.changeColor(raw_ostream::YELLOW, true); 3755 3756 OS << "\n [B" << B.getBlockID(); 3757 3758 if (&B == &cfg->getEntry()) 3759 OS << " (ENTRY)]\n"; 3760 else if (&B == &cfg->getExit()) 3761 OS << " (EXIT)]\n"; 3762 else if (&B == cfg->getIndirectGotoBlock()) 3763 OS << " (INDIRECT GOTO DISPATCH)]\n"; 3764 else 3765 OS << "]\n"; 3766 3767 if (ShowColors) 3768 OS.resetColor(); 3769 3770 // Print the label of this block. 3771 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3772 3773 if (print_edges) 3774 OS << " "; 3775 3776 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3777 OS << L->getName(); 3778 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3779 OS << "case "; 3780 C->getLHS()->printPretty(OS, Helper, 3781 PrintingPolicy(Helper->getLangOpts())); 3782 if (C->getRHS()) { 3783 OS << " ... "; 3784 C->getRHS()->printPretty(OS, Helper, 3785 PrintingPolicy(Helper->getLangOpts())); 3786 } 3787 } else if (isa<DefaultStmt>(Label)) 3788 OS << "default"; 3789 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3790 OS << "catch ("; 3791 if (CS->getExceptionDecl()) 3792 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3793 0); 3794 else 3795 OS << "..."; 3796 OS << ")"; 3797 3798 } else 3799 llvm_unreachable("Invalid label statement in CFGBlock."); 3800 3801 OS << ":\n"; 3802 } 3803 3804 // Iterate through the statements in the block and print them. 3805 unsigned j = 1; 3806 3807 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3808 I != E ; ++I, ++j ) { 3809 3810 // Print the statement # in the basic block and the statement itself. 3811 if (print_edges) 3812 OS << " "; 3813 3814 OS << llvm::format("%3d", j) << ": "; 3815 3816 if (Helper) 3817 Helper->setStmtID(j); 3818 3819 print_elem(OS, Helper, *I); 3820 } 3821 3822 // Print the terminator of this block. 3823 if (B.getTerminator()) { 3824 if (ShowColors) 3825 OS.changeColor(raw_ostream::GREEN); 3826 3827 OS << " T: "; 3828 3829 if (Helper) Helper->setBlockID(-1); 3830 3831 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3832 PrintingPolicy(Helper->getLangOpts())); 3833 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3834 OS << '\n'; 3835 3836 if (ShowColors) 3837 OS.resetColor(); 3838 } 3839 3840 if (print_edges) { 3841 // Print the predecessors of this block. 3842 if (!B.pred_empty()) { 3843 const raw_ostream::Colors Color = raw_ostream::BLUE; 3844 if (ShowColors) 3845 OS.changeColor(Color); 3846 OS << " Preds " ; 3847 if (ShowColors) 3848 OS.resetColor(); 3849 OS << '(' << B.pred_size() << "):"; 3850 unsigned i = 0; 3851 3852 if (ShowColors) 3853 OS.changeColor(Color); 3854 3855 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3856 I != E; ++I, ++i) { 3857 3858 if (i == 8 || (i-8) == 0) 3859 OS << "\n "; 3860 3861 OS << " B" << (*I)->getBlockID(); 3862 } 3863 3864 if (ShowColors) 3865 OS.resetColor(); 3866 3867 OS << '\n'; 3868 } 3869 3870 // Print the successors of this block. 3871 if (!B.succ_empty()) { 3872 const raw_ostream::Colors Color = raw_ostream::MAGENTA; 3873 if (ShowColors) 3874 OS.changeColor(Color); 3875 OS << " Succs "; 3876 if (ShowColors) 3877 OS.resetColor(); 3878 OS << '(' << B.succ_size() << "):"; 3879 unsigned i = 0; 3880 3881 if (ShowColors) 3882 OS.changeColor(Color); 3883 3884 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3885 I != E; ++I, ++i) { 3886 3887 if (i == 8 || (i-8) % 10 == 0) 3888 OS << "\n "; 3889 3890 if (*I) 3891 OS << " B" << (*I)->getBlockID(); 3892 else 3893 OS << " NULL"; 3894 } 3895 3896 if (ShowColors) 3897 OS.resetColor(); 3898 OS << '\n'; 3899 } 3900 } 3901} 3902 3903 3904/// dump - A simple pretty printer of a CFG that outputs to stderr. 3905void CFG::dump(const LangOptions &LO, bool ShowColors) const { 3906 print(llvm::errs(), LO, ShowColors); 3907} 3908 3909/// print - A simple pretty printer of a CFG that outputs to an ostream. 3910void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const { 3911 StmtPrinterHelper Helper(this, LO); 3912 3913 // Print the entry block. 3914 print_block(OS, this, getEntry(), &Helper, true, ShowColors); 3915 3916 // Iterate through the CFGBlocks and print them one by one. 3917 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3918 // Skip the entry block, because we already printed it. 3919 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3920 continue; 3921 3922 print_block(OS, this, **I, &Helper, true, ShowColors); 3923 } 3924 3925 // Print the exit block. 3926 print_block(OS, this, getExit(), &Helper, true, ShowColors); 3927 OS << '\n'; 3928 OS.flush(); 3929} 3930 3931/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3932void CFGBlock::dump(const CFG* cfg, const LangOptions &LO, 3933 bool ShowColors) const { 3934 print(llvm::errs(), cfg, LO, ShowColors); 3935} 3936 3937/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3938/// Generally this will only be called from CFG::print. 3939void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3940 const LangOptions &LO, bool ShowColors) const { 3941 StmtPrinterHelper Helper(cfg, LO); 3942 print_block(OS, cfg, *this, &Helper, true, ShowColors); 3943 OS << '\n'; 3944} 3945 3946/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3947void CFGBlock::printTerminator(raw_ostream &OS, 3948 const LangOptions &LO) const { 3949 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3950 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3951} 3952 3953Stmt *CFGBlock::getTerminatorCondition() { 3954 Stmt *Terminator = this->Terminator; 3955 if (!Terminator) 3956 return NULL; 3957 3958 Expr *E = NULL; 3959 3960 switch (Terminator->getStmtClass()) { 3961 default: 3962 break; 3963 3964 case Stmt::ForStmtClass: 3965 E = cast<ForStmt>(Terminator)->getCond(); 3966 break; 3967 3968 case Stmt::WhileStmtClass: 3969 E = cast<WhileStmt>(Terminator)->getCond(); 3970 break; 3971 3972 case Stmt::DoStmtClass: 3973 E = cast<DoStmt>(Terminator)->getCond(); 3974 break; 3975 3976 case Stmt::IfStmtClass: 3977 E = cast<IfStmt>(Terminator)->getCond(); 3978 break; 3979 3980 case Stmt::ChooseExprClass: 3981 E = cast<ChooseExpr>(Terminator)->getCond(); 3982 break; 3983 3984 case Stmt::IndirectGotoStmtClass: 3985 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3986 break; 3987 3988 case Stmt::SwitchStmtClass: 3989 E = cast<SwitchStmt>(Terminator)->getCond(); 3990 break; 3991 3992 case Stmt::BinaryConditionalOperatorClass: 3993 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3994 break; 3995 3996 case Stmt::ConditionalOperatorClass: 3997 E = cast<ConditionalOperator>(Terminator)->getCond(); 3998 break; 3999 4000 case Stmt::BinaryOperatorClass: // '&&' and '||' 4001 E = cast<BinaryOperator>(Terminator)->getLHS(); 4002 break; 4003 4004 case Stmt::ObjCForCollectionStmtClass: 4005 return Terminator; 4006 } 4007 4008 return E ? E->IgnoreParens() : NULL; 4009} 4010 4011//===----------------------------------------------------------------------===// 4012// CFG Graphviz Visualization 4013//===----------------------------------------------------------------------===// 4014 4015 4016#ifndef NDEBUG 4017static StmtPrinterHelper* GraphHelper; 4018#endif 4019 4020void CFG::viewCFG(const LangOptions &LO) const { 4021#ifndef NDEBUG 4022 StmtPrinterHelper H(this, LO); 4023 GraphHelper = &H; 4024 llvm::ViewGraph(this,"CFG"); 4025 GraphHelper = NULL; 4026#endif 4027} 4028 4029namespace llvm { 4030template<> 4031struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 4032 4033 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 4034 4035 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 4036 4037#ifndef NDEBUG 4038 std::string OutSStr; 4039 llvm::raw_string_ostream Out(OutSStr); 4040 print_block(Out,Graph, *Node, GraphHelper, false, false); 4041 std::string& OutStr = Out.str(); 4042 4043 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 4044 4045 // Process string output to make it nicer... 4046 for (unsigned i = 0; i != OutStr.length(); ++i) 4047 if (OutStr[i] == '\n') { // Left justify 4048 OutStr[i] = '\\'; 4049 OutStr.insert(OutStr.begin()+i+1, 'l'); 4050 } 4051 4052 return OutStr; 4053#else 4054 return ""; 4055#endif 4056 } 4057}; 4058} // end namespace llvm 4059