CFG.cpp revision ac73ea8c12772fd0dcec71b83c193a2837de7f8b
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "clang/AST/CharUnits.h" 21#include "llvm/Support/GraphWriter.h" 22#include "llvm/Support/Allocator.h" 23#include "llvm/Support/Format.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/OwningPtr.h" 27 28using namespace clang; 29 30namespace { 31 32static SourceLocation GetEndLoc(Decl* D) { 33 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 34 if (Expr* Ex = VD->getInit()) 35 return Ex->getSourceRange().getEnd(); 36 return D->getLocation(); 37} 38 39class CFGBuilder; 40 41/// The CFG builder uses a recursive algorithm to build the CFG. When 42/// we process an expression, sometimes we know that we must add the 43/// subexpressions as block-level expressions. For example: 44/// 45/// exp1 || exp2 46/// 47/// When processing the '||' expression, we know that exp1 and exp2 48/// need to be added as block-level expressions, even though they 49/// might not normally need to be. AddStmtChoice records this 50/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 51/// the builder has an option not to add a subexpression as a 52/// block-level expression. 53/// 54class AddStmtChoice { 55public: 56 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 57 58 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 59 60 bool alwaysAdd(CFGBuilder &builder, 61 const Stmt *stmt) const; 62 63 /// Return a copy of this object, except with the 'always-add' bit 64 /// set as specified. 65 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 66 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 67 } 68 69private: 70 Kind kind; 71}; 72 73/// LocalScope - Node in tree of local scopes created for C++ implicit 74/// destructor calls generation. It contains list of automatic variables 75/// declared in the scope and link to position in previous scope this scope 76/// began in. 77/// 78/// The process of creating local scopes is as follows: 79/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 80/// - Before processing statements in scope (e.g. CompoundStmt) create 81/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 82/// and set CFGBuilder::ScopePos to the end of new scope, 83/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 84/// at this VarDecl, 85/// - For every normal (without jump) end of scope add to CFGBlock destructors 86/// for objects in the current scope, 87/// - For every jump add to CFGBlock destructors for objects 88/// between CFGBuilder::ScopePos and local scope position saved for jump 89/// target. Thanks to C++ restrictions on goto jumps we can be sure that 90/// jump target position will be on the path to root from CFGBuilder::ScopePos 91/// (adding any variable that doesn't need constructor to be called to 92/// LocalScope can break this assumption), 93/// 94class LocalScope { 95public: 96 typedef BumpVector<VarDecl*> AutomaticVarsTy; 97 98 /// const_iterator - Iterates local scope backwards and jumps to previous 99 /// scope on reaching the beginning of currently iterated scope. 100 class const_iterator { 101 const LocalScope* Scope; 102 103 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 104 /// Invalid iterator (with null Scope) has VarIter equal to 0. 105 unsigned VarIter; 106 107 public: 108 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 109 /// Incrementing invalid iterator is allowed and will result in invalid 110 /// iterator. 111 const_iterator() 112 : Scope(NULL), VarIter(0) {} 113 114 /// Create valid iterator. In case when S.Prev is an invalid iterator and 115 /// I is equal to 0, this will create invalid iterator. 116 const_iterator(const LocalScope& S, unsigned I) 117 : Scope(&S), VarIter(I) { 118 // Iterator to "end" of scope is not allowed. Handle it by going up 119 // in scopes tree possibly up to invalid iterator in the root. 120 if (VarIter == 0 && Scope) 121 *this = Scope->Prev; 122 } 123 124 VarDecl* const* operator->() const { 125 assert (Scope && "Dereferencing invalid iterator is not allowed"); 126 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 127 return &Scope->Vars[VarIter - 1]; 128 } 129 VarDecl* operator*() const { 130 return *this->operator->(); 131 } 132 133 const_iterator& operator++() { 134 if (!Scope) 135 return *this; 136 137 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 138 --VarIter; 139 if (VarIter == 0) 140 *this = Scope->Prev; 141 return *this; 142 } 143 const_iterator operator++(int) { 144 const_iterator P = *this; 145 ++*this; 146 return P; 147 } 148 149 bool operator==(const const_iterator& rhs) const { 150 return Scope == rhs.Scope && VarIter == rhs.VarIter; 151 } 152 bool operator!=(const const_iterator& rhs) const { 153 return !(*this == rhs); 154 } 155 156 operator bool() const { 157 return *this != const_iterator(); 158 } 159 160 int distance(const_iterator L); 161 }; 162 163 friend class const_iterator; 164 165private: 166 BumpVectorContext ctx; 167 168 /// Automatic variables in order of declaration. 169 AutomaticVarsTy Vars; 170 /// Iterator to variable in previous scope that was declared just before 171 /// begin of this scope. 172 const_iterator Prev; 173 174public: 175 /// Constructs empty scope linked to previous scope in specified place. 176 LocalScope(BumpVectorContext &ctx, const_iterator P) 177 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 178 179 /// Begin of scope in direction of CFG building (backwards). 180 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 181 182 void addVar(VarDecl* VD) { 183 Vars.push_back(VD, ctx); 184 } 185}; 186 187/// distance - Calculates distance from this to L. L must be reachable from this 188/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 189/// number of scopes between this and L. 190int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 191 int D = 0; 192 const_iterator F = *this; 193 while (F.Scope != L.Scope) { 194 assert (F != const_iterator() 195 && "L iterator is not reachable from F iterator."); 196 D += F.VarIter; 197 F = F.Scope->Prev; 198 } 199 D += F.VarIter - L.VarIter; 200 return D; 201} 202 203/// BlockScopePosPair - Structure for specifying position in CFG during its 204/// build process. It consists of CFGBlock that specifies position in CFG graph 205/// and LocalScope::const_iterator that specifies position in LocalScope graph. 206struct BlockScopePosPair { 207 BlockScopePosPair() : block(0) {} 208 BlockScopePosPair(CFGBlock* b, LocalScope::const_iterator scopePos) 209 : block(b), scopePosition(scopePos) {} 210 211 CFGBlock *block; 212 LocalScope::const_iterator scopePosition; 213}; 214 215/// TryResult - a class representing a variant over the values 216/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 217/// and is used by the CFGBuilder to decide if a branch condition 218/// can be decided up front during CFG construction. 219class TryResult { 220 int X; 221public: 222 TryResult(bool b) : X(b ? 1 : 0) {} 223 TryResult() : X(-1) {} 224 225 bool isTrue() const { return X == 1; } 226 bool isFalse() const { return X == 0; } 227 bool isKnown() const { return X >= 0; } 228 void negate() { 229 assert(isKnown()); 230 X ^= 0x1; 231 } 232}; 233 234/// CFGBuilder - This class implements CFG construction from an AST. 235/// The builder is stateful: an instance of the builder should be used to only 236/// construct a single CFG. 237/// 238/// Example usage: 239/// 240/// CFGBuilder builder; 241/// CFG* cfg = builder.BuildAST(stmt1); 242/// 243/// CFG construction is done via a recursive walk of an AST. We actually parse 244/// the AST in reverse order so that the successor of a basic block is 245/// constructed prior to its predecessor. This allows us to nicely capture 246/// implicit fall-throughs without extra basic blocks. 247/// 248class CFGBuilder { 249 typedef BlockScopePosPair JumpTarget; 250 typedef BlockScopePosPair JumpSource; 251 252 ASTContext *Context; 253 llvm::OwningPtr<CFG> cfg; 254 255 CFGBlock* Block; 256 CFGBlock* Succ; 257 JumpTarget ContinueJumpTarget; 258 JumpTarget BreakJumpTarget; 259 CFGBlock* SwitchTerminatedBlock; 260 CFGBlock* DefaultCaseBlock; 261 CFGBlock* TryTerminatedBlock; 262 263 // Current position in local scope. 264 LocalScope::const_iterator ScopePos; 265 266 // LabelMap records the mapping from Label expressions to their jump targets. 267 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 268 LabelMapTy LabelMap; 269 270 // A list of blocks that end with a "goto" that must be backpatched to their 271 // resolved targets upon completion of CFG construction. 272 typedef std::vector<JumpSource> BackpatchBlocksTy; 273 BackpatchBlocksTy BackpatchBlocks; 274 275 // A list of labels whose address has been taken (for indirect gotos). 276 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 277 LabelSetTy AddressTakenLabels; 278 279 bool badCFG; 280 const CFG::BuildOptions &BuildOpts; 281 282 // State to track for building switch statements. 283 bool switchExclusivelyCovered; 284 Expr::EvalResult *switchCond; 285 286 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 287 const Stmt *lastLookup; 288 289public: 290 explicit CFGBuilder(ASTContext *astContext, 291 const CFG::BuildOptions &buildOpts) 292 : Context(astContext), cfg(new CFG()), // crew a new CFG 293 Block(NULL), Succ(NULL), 294 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 295 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 296 switchExclusivelyCovered(false), switchCond(0), 297 cachedEntry(0), lastLookup(0) {} 298 299 // buildCFG - Used by external clients to construct the CFG. 300 CFG* buildCFG(const Decl *D, Stmt *Statement); 301 302 bool alwaysAdd(const Stmt *stmt); 303 304private: 305 // Visitors to walk an AST and construct the CFG. 306 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 307 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 308 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 309 CFGBlock *VisitBreakStmt(BreakStmt *B); 310 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 311 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 312 AddStmtChoice asc); 313 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 314 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 315 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 316 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 317 AddStmtChoice asc); 318 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 319 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 320 AddStmtChoice asc); 321 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 322 AddStmtChoice asc); 323 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 324 CFGBlock *VisitCaseStmt(CaseStmt *C); 325 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 326 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 327 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 328 AddStmtChoice asc); 329 CFGBlock *VisitContinueStmt(ContinueStmt *C); 330 CFGBlock *VisitDeclStmt(DeclStmt *DS); 331 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 332 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 333 CFGBlock *VisitDoStmt(DoStmt *D); 334 CFGBlock *VisitForStmt(ForStmt *F); 335 CFGBlock *VisitGotoStmt(GotoStmt* G); 336 CFGBlock *VisitIfStmt(IfStmt *I); 337 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 338 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 339 CFGBlock *VisitLabelStmt(LabelStmt *L); 340 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 341 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 342 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 343 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 344 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 345 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 346 CFGBlock *VisitReturnStmt(ReturnStmt* R); 347 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 348 AddStmtChoice asc); 349 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 350 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 351 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 352 CFGBlock *VisitWhileStmt(WhileStmt *W); 353 354 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 355 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 356 CFGBlock *VisitChildren(Stmt* S); 357 358 // Visitors to walk an AST and generate destructors of temporaries in 359 // full expression. 360 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 361 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 362 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 363 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 364 bool BindToTemporary); 365 CFGBlock * 366 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 367 bool BindToTemporary); 368 369 // NYS == Not Yet Supported 370 CFGBlock* NYS() { 371 badCFG = true; 372 return Block; 373 } 374 375 void autoCreateBlock() { if (!Block) Block = createBlock(); } 376 CFGBlock *createBlock(bool add_successor = true); 377 378 CFGBlock *addStmt(Stmt *S) { 379 return Visit(S, AddStmtChoice::AlwaysAdd); 380 } 381 CFGBlock *addInitializer(CXXCtorInitializer *I); 382 void addAutomaticObjDtors(LocalScope::const_iterator B, 383 LocalScope::const_iterator E, Stmt* S); 384 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 385 386 // Local scopes creation. 387 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 388 389 void addLocalScopeForStmt(Stmt* S); 390 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 391 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 392 393 void addLocalScopeAndDtors(Stmt* S); 394 395 // Interface to CFGBlock - adding CFGElements. 396 void appendStmt(CFGBlock *B, const Stmt *S) { 397 if (alwaysAdd(S)) 398 cachedEntry->second = B; 399 400 // All block-level expressions should have already been IgnoreParens()ed. 401 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 402 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 403 } 404 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 405 B->appendInitializer(I, cfg->getBumpVectorContext()); 406 } 407 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 408 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 409 } 410 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 411 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 412 } 413 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 414 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 415 } 416 417 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 418 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 419 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 420 LocalScope::const_iterator E, Stmt* S); 421 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 422 LocalScope::const_iterator B, LocalScope::const_iterator E); 423 424 void addSuccessor(CFGBlock *B, CFGBlock *S) { 425 B->addSuccessor(S, cfg->getBumpVectorContext()); 426 } 427 428 /// Try and evaluate an expression to an integer constant. 429 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 430 if (!BuildOpts.PruneTriviallyFalseEdges) 431 return false; 432 return !S->isTypeDependent() && 433 !S->isValueDependent() && 434 S->Evaluate(outResult, *Context); 435 } 436 437 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 438 /// if we can evaluate to a known value, otherwise return -1. 439 TryResult tryEvaluateBool(Expr *S) { 440 Expr::EvalResult Result; 441 if (!tryEvaluate(S, Result)) 442 return TryResult(); 443 444 if (Result.Val.isInt()) 445 return Result.Val.getInt().getBoolValue(); 446 447 if (Result.Val.isLValue()) { 448 const Expr *e = Result.Val.getLValueBase(); 449 const CharUnits &c = Result.Val.getLValueOffset(); 450 if (!e && c.isZero()) 451 return false; 452 } 453 return TryResult(); 454 } 455 456}; 457 458inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 459 const Stmt *stmt) const { 460 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 461} 462 463bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 464 if (!BuildOpts.forcedBlkExprs) 465 return false; 466 467 if (lastLookup == stmt) { 468 if (cachedEntry) { 469 assert(cachedEntry->first == stmt); 470 return true; 471 } 472 return false; 473 } 474 475 lastLookup = stmt; 476 477 // Perform the lookup! 478 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 479 480 if (!fb) { 481 // No need to update 'cachedEntry', since it will always be null. 482 assert(cachedEntry == 0); 483 return false; 484 } 485 486 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 487 if (itr == fb->end()) { 488 cachedEntry = 0; 489 return false; 490 } 491 492 cachedEntry = &*itr; 493 return true; 494} 495 496// FIXME: Add support for dependent-sized array types in C++? 497// Does it even make sense to build a CFG for an uninstantiated template? 498static const VariableArrayType *FindVA(const Type *t) { 499 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 500 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 501 if (vat->getSizeExpr()) 502 return vat; 503 504 t = vt->getElementType().getTypePtr(); 505 } 506 507 return 0; 508} 509 510/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 511/// arbitrary statement. Examples include a single expression or a function 512/// body (compound statement). The ownership of the returned CFG is 513/// transferred to the caller. If CFG construction fails, this method returns 514/// NULL. 515CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement) { 516 assert(cfg.get()); 517 if (!Statement) 518 return NULL; 519 520 // Create an empty block that will serve as the exit block for the CFG. Since 521 // this is the first block added to the CFG, it will be implicitly registered 522 // as the exit block. 523 Succ = createBlock(); 524 assert(Succ == &cfg->getExit()); 525 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 526 527 if (BuildOpts.AddImplicitDtors) 528 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 529 addImplicitDtorsForDestructor(DD); 530 531 // Visit the statements and create the CFG. 532 CFGBlock *B = addStmt(Statement); 533 534 if (badCFG) 535 return NULL; 536 537 // For C++ constructor add initializers to CFG. 538 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 539 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 540 E = CD->init_rend(); I != E; ++I) { 541 B = addInitializer(*I); 542 if (badCFG) 543 return NULL; 544 } 545 } 546 547 if (B) 548 Succ = B; 549 550 // Backpatch the gotos whose label -> block mappings we didn't know when we 551 // encountered them. 552 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 553 E = BackpatchBlocks.end(); I != E; ++I ) { 554 555 CFGBlock* B = I->block; 556 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 557 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 558 559 // If there is no target for the goto, then we are looking at an 560 // incomplete AST. Handle this by not registering a successor. 561 if (LI == LabelMap.end()) continue; 562 563 JumpTarget JT = LI->second; 564 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 565 JT.scopePosition); 566 addSuccessor(B, JT.block); 567 } 568 569 // Add successors to the Indirect Goto Dispatch block (if we have one). 570 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 571 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 572 E = AddressTakenLabels.end(); I != E; ++I ) { 573 574 // Lookup the target block. 575 LabelMapTy::iterator LI = LabelMap.find(*I); 576 577 // If there is no target block that contains label, then we are looking 578 // at an incomplete AST. Handle this by not registering a successor. 579 if (LI == LabelMap.end()) continue; 580 581 addSuccessor(B, LI->second.block); 582 } 583 584 // Create an empty entry block that has no predecessors. 585 cfg->setEntry(createBlock()); 586 587 return cfg.take(); 588} 589 590/// createBlock - Used to lazily create blocks that are connected 591/// to the current (global) succcessor. 592CFGBlock* CFGBuilder::createBlock(bool add_successor) { 593 CFGBlock* B = cfg->createBlock(); 594 if (add_successor && Succ) 595 addSuccessor(B, Succ); 596 return B; 597} 598 599/// addInitializer - Add C++ base or member initializer element to CFG. 600CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 601 if (!BuildOpts.AddInitializers) 602 return Block; 603 604 bool IsReference = false; 605 bool HasTemporaries = false; 606 607 // Destructors of temporaries in initialization expression should be called 608 // after initialization finishes. 609 Expr *Init = I->getInit(); 610 if (Init) { 611 if (FieldDecl *FD = I->getAnyMember()) 612 IsReference = FD->getType()->isReferenceType(); 613 HasTemporaries = isa<ExprWithCleanups>(Init); 614 615 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 616 // Generate destructors for temporaries in initialization expression. 617 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 618 IsReference); 619 } 620 } 621 622 autoCreateBlock(); 623 appendInitializer(Block, I); 624 625 if (Init) { 626 if (HasTemporaries) { 627 // For expression with temporaries go directly to subexpression to omit 628 // generating destructors for the second time. 629 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 630 } 631 return Visit(Init); 632 } 633 634 return Block; 635} 636 637/// addAutomaticObjDtors - Add to current block automatic objects destructors 638/// for objects in range of local scope positions. Use S as trigger statement 639/// for destructors. 640void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 641 LocalScope::const_iterator E, Stmt* S) { 642 if (!BuildOpts.AddImplicitDtors) 643 return; 644 645 if (B == E) 646 return; 647 648 autoCreateBlock(); 649 appendAutomaticObjDtors(Block, B, E, S); 650} 651 652/// addImplicitDtorsForDestructor - Add implicit destructors generated for 653/// base and member objects in destructor. 654void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 655 assert (BuildOpts.AddImplicitDtors 656 && "Can be called only when dtors should be added"); 657 const CXXRecordDecl *RD = DD->getParent(); 658 659 // At the end destroy virtual base objects. 660 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 661 VE = RD->vbases_end(); VI != VE; ++VI) { 662 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 663 if (!CD->hasTrivialDestructor()) { 664 autoCreateBlock(); 665 appendBaseDtor(Block, VI); 666 } 667 } 668 669 // Before virtual bases destroy direct base objects. 670 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 671 BE = RD->bases_end(); BI != BE; ++BI) { 672 if (!BI->isVirtual()) { 673 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 674 if (!CD->hasTrivialDestructor()) { 675 autoCreateBlock(); 676 appendBaseDtor(Block, BI); 677 } 678 } 679 } 680 681 // First destroy member objects. 682 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 683 FE = RD->field_end(); FI != FE; ++FI) { 684 // Check for constant size array. Set type to array element type. 685 QualType QT = FI->getType(); 686 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 687 if (AT->getSize() == 0) 688 continue; 689 QT = AT->getElementType(); 690 } 691 692 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 693 if (!CD->hasTrivialDestructor()) { 694 autoCreateBlock(); 695 appendMemberDtor(Block, *FI); 696 } 697 } 698} 699 700/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 701/// way return valid LocalScope object. 702LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 703 if (!Scope) { 704 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 705 Scope = alloc.Allocate<LocalScope>(); 706 BumpVectorContext ctx(alloc); 707 new (Scope) LocalScope(ctx, ScopePos); 708 } 709 return Scope; 710} 711 712/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 713/// that should create implicit scope (e.g. if/else substatements). 714void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 715 if (!BuildOpts.AddImplicitDtors) 716 return; 717 718 LocalScope *Scope = 0; 719 720 // For compound statement we will be creating explicit scope. 721 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 722 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 723 ; BI != BE; ++BI) { 724 Stmt *SI = *BI; 725 if (LabelStmt *LS = dyn_cast<LabelStmt>(SI)) 726 SI = LS->getSubStmt(); 727 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 728 Scope = addLocalScopeForDeclStmt(DS, Scope); 729 } 730 return; 731 } 732 733 // For any other statement scope will be implicit and as such will be 734 // interesting only for DeclStmt. 735 if (LabelStmt *LS = dyn_cast<LabelStmt>(S)) 736 S = LS->getSubStmt(); 737 if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) 738 addLocalScopeForDeclStmt(DS); 739} 740 741/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 742/// reuse Scope if not NULL. 743LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 744 LocalScope* Scope) { 745 if (!BuildOpts.AddImplicitDtors) 746 return Scope; 747 748 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 749 ; DI != DE; ++DI) { 750 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 751 Scope = addLocalScopeForVarDecl(VD, Scope); 752 } 753 return Scope; 754} 755 756/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 757/// create add scope for automatic objects and temporary objects bound to 758/// const reference. Will reuse Scope if not NULL. 759LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 760 LocalScope* Scope) { 761 if (!BuildOpts.AddImplicitDtors) 762 return Scope; 763 764 // Check if variable is local. 765 switch (VD->getStorageClass()) { 766 case SC_None: 767 case SC_Auto: 768 case SC_Register: 769 break; 770 default: return Scope; 771 } 772 773 // Check for const references bound to temporary. Set type to pointee. 774 QualType QT = VD->getType(); 775 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 776 QT = RT->getPointeeType(); 777 if (!QT.isConstQualified()) 778 return Scope; 779 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 780 return Scope; 781 } 782 783 // Check for constant size array. Set type to array element type. 784 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 785 if (AT->getSize() == 0) 786 return Scope; 787 QT = AT->getElementType(); 788 } 789 790 // Check if type is a C++ class with non-trivial destructor. 791 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 792 if (!CD->hasTrivialDestructor()) { 793 // Add the variable to scope 794 Scope = createOrReuseLocalScope(Scope); 795 Scope->addVar(VD); 796 ScopePos = Scope->begin(); 797 } 798 return Scope; 799} 800 801/// addLocalScopeAndDtors - For given statement add local scope for it and 802/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 803void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 804 if (!BuildOpts.AddImplicitDtors) 805 return; 806 807 LocalScope::const_iterator scopeBeginPos = ScopePos; 808 addLocalScopeForStmt(S); 809 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 810} 811 812/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 813/// automatic storage duration to CFGBlock's elements vector. Insertion will be 814/// performed in place specified with iterator. 815void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 816 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 817 BumpVectorContext& C = cfg->getBumpVectorContext(); 818 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 819 while (B != E) 820 I = Blk->insertAutomaticObjDtor(I, *B++, S); 821} 822 823/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 824/// automatic storage duration to CFGBlock's elements vector. Elements will be 825/// appended to physical end of the vector which happens to be logical 826/// beginning. 827void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 828 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 829 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 830} 831 832/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 833/// variables with automatic storage duration to CFGBlock's elements vector. 834/// Elements will be prepended to physical beginning of the vector which 835/// happens to be logical end. Use blocks terminator as statement that specifies 836/// destructors call site. 837void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 838 LocalScope::const_iterator B, LocalScope::const_iterator E) { 839 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 840} 841 842/// Visit - Walk the subtree of a statement and add extra 843/// blocks for ternary operators, &&, and ||. We also process "," and 844/// DeclStmts (which may contain nested control-flow). 845CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 846 if (!S) { 847 badCFG = true; 848 return 0; 849 } 850 851 if (Expr *E = dyn_cast<Expr>(S)) 852 S = E->IgnoreParens(); 853 854 switch (S->getStmtClass()) { 855 default: 856 return VisitStmt(S, asc); 857 858 case Stmt::AddrLabelExprClass: 859 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 860 861 case Stmt::BinaryConditionalOperatorClass: 862 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 863 864 case Stmt::BinaryOperatorClass: 865 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 866 867 case Stmt::BlockExprClass: 868 return VisitBlockExpr(cast<BlockExpr>(S), asc); 869 870 case Stmt::BreakStmtClass: 871 return VisitBreakStmt(cast<BreakStmt>(S)); 872 873 case Stmt::CallExprClass: 874 case Stmt::CXXOperatorCallExprClass: 875 case Stmt::CXXMemberCallExprClass: 876 return VisitCallExpr(cast<CallExpr>(S), asc); 877 878 case Stmt::CaseStmtClass: 879 return VisitCaseStmt(cast<CaseStmt>(S)); 880 881 case Stmt::ChooseExprClass: 882 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 883 884 case Stmt::CompoundStmtClass: 885 return VisitCompoundStmt(cast<CompoundStmt>(S)); 886 887 case Stmt::ConditionalOperatorClass: 888 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 889 890 case Stmt::ContinueStmtClass: 891 return VisitContinueStmt(cast<ContinueStmt>(S)); 892 893 case Stmt::CXXCatchStmtClass: 894 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 895 896 case Stmt::ExprWithCleanupsClass: 897 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 898 899 case Stmt::CXXBindTemporaryExprClass: 900 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 901 902 case Stmt::CXXConstructExprClass: 903 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 904 905 case Stmt::CXXFunctionalCastExprClass: 906 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 907 908 case Stmt::CXXTemporaryObjectExprClass: 909 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 910 911 case Stmt::CXXThrowExprClass: 912 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 913 914 case Stmt::CXXTryStmtClass: 915 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 916 917 case Stmt::CXXForRangeStmtClass: 918 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 919 920 case Stmt::DeclStmtClass: 921 return VisitDeclStmt(cast<DeclStmt>(S)); 922 923 case Stmt::DefaultStmtClass: 924 return VisitDefaultStmt(cast<DefaultStmt>(S)); 925 926 case Stmt::DoStmtClass: 927 return VisitDoStmt(cast<DoStmt>(S)); 928 929 case Stmt::ForStmtClass: 930 return VisitForStmt(cast<ForStmt>(S)); 931 932 case Stmt::GotoStmtClass: 933 return VisitGotoStmt(cast<GotoStmt>(S)); 934 935 case Stmt::IfStmtClass: 936 return VisitIfStmt(cast<IfStmt>(S)); 937 938 case Stmt::ImplicitCastExprClass: 939 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 940 941 case Stmt::IndirectGotoStmtClass: 942 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 943 944 case Stmt::LabelStmtClass: 945 return VisitLabelStmt(cast<LabelStmt>(S)); 946 947 case Stmt::MemberExprClass: 948 return VisitMemberExpr(cast<MemberExpr>(S), asc); 949 950 case Stmt::ObjCAtCatchStmtClass: 951 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 952 953 case Stmt::ObjCAtSynchronizedStmtClass: 954 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 955 956 case Stmt::ObjCAtThrowStmtClass: 957 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 958 959 case Stmt::ObjCAtTryStmtClass: 960 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 961 962 case Stmt::ObjCForCollectionStmtClass: 963 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 964 965 case Stmt::NullStmtClass: 966 return Block; 967 968 case Stmt::ReturnStmtClass: 969 return VisitReturnStmt(cast<ReturnStmt>(S)); 970 971 case Stmt::UnaryExprOrTypeTraitExprClass: 972 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 973 asc); 974 975 case Stmt::StmtExprClass: 976 return VisitStmtExpr(cast<StmtExpr>(S), asc); 977 978 case Stmt::SwitchStmtClass: 979 return VisitSwitchStmt(cast<SwitchStmt>(S)); 980 981 case Stmt::UnaryOperatorClass: 982 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 983 984 case Stmt::WhileStmtClass: 985 return VisitWhileStmt(cast<WhileStmt>(S)); 986 } 987} 988 989CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 990 if (asc.alwaysAdd(*this, S)) { 991 autoCreateBlock(); 992 appendStmt(Block, S); 993 } 994 995 return VisitChildren(S); 996} 997 998/// VisitChildren - Visit the children of a Stmt. 999CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 1000 CFGBlock *lastBlock = Block; 1001 for (Stmt::child_range I = Terminator->children(); I; ++I) 1002 if (Stmt *child = *I) 1003 if (CFGBlock *b = Visit(child)) 1004 lastBlock = b; 1005 1006 return lastBlock; 1007} 1008 1009CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1010 AddStmtChoice asc) { 1011 AddressTakenLabels.insert(A->getLabel()); 1012 1013 if (asc.alwaysAdd(*this, A)) { 1014 autoCreateBlock(); 1015 appendStmt(Block, A); 1016 } 1017 1018 return Block; 1019} 1020 1021CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1022 AddStmtChoice asc) { 1023 if (asc.alwaysAdd(*this, U)) { 1024 autoCreateBlock(); 1025 appendStmt(Block, U); 1026 } 1027 1028 return Visit(U->getSubExpr(), AddStmtChoice()); 1029} 1030 1031CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1032 AddStmtChoice asc) { 1033 if (B->isLogicalOp()) { // && or || 1034 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1035 appendStmt(ConfluenceBlock, B); 1036 1037 if (badCFG) 1038 return 0; 1039 1040 // create the block evaluating the LHS 1041 CFGBlock* LHSBlock = createBlock(false); 1042 LHSBlock->setTerminator(B); 1043 1044 // create the block evaluating the RHS 1045 Succ = ConfluenceBlock; 1046 Block = NULL; 1047 CFGBlock* RHSBlock = addStmt(B->getRHS()); 1048 1049 if (RHSBlock) { 1050 if (badCFG) 1051 return 0; 1052 } else { 1053 // Create an empty block for cases where the RHS doesn't require 1054 // any explicit statements in the CFG. 1055 RHSBlock = createBlock(); 1056 } 1057 1058 // See if this is a known constant. 1059 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1060 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1061 KnownVal.negate(); 1062 1063 // Now link the LHSBlock with RHSBlock. 1064 if (B->getOpcode() == BO_LOr) { 1065 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1066 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1067 } else { 1068 assert(B->getOpcode() == BO_LAnd); 1069 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1070 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1071 } 1072 1073 // Generate the blocks for evaluating the LHS. 1074 Block = LHSBlock; 1075 return addStmt(B->getLHS()); 1076 } 1077 1078 if (B->getOpcode() == BO_Comma) { // , 1079 autoCreateBlock(); 1080 appendStmt(Block, B); 1081 addStmt(B->getRHS()); 1082 return addStmt(B->getLHS()); 1083 } 1084 1085 if (B->isAssignmentOp()) { 1086 if (asc.alwaysAdd(*this, B)) { 1087 autoCreateBlock(); 1088 appendStmt(Block, B); 1089 } 1090 Visit(B->getLHS()); 1091 return Visit(B->getRHS()); 1092 } 1093 1094 if (asc.alwaysAdd(*this, B)) { 1095 autoCreateBlock(); 1096 appendStmt(Block, B); 1097 } 1098 1099 CFGBlock *RBlock = Visit(B->getRHS()); 1100 CFGBlock *LBlock = Visit(B->getLHS()); 1101 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1102 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1103 // return RBlock. Otherwise we'll incorrectly return NULL. 1104 return (LBlock ? LBlock : RBlock); 1105} 1106 1107CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1108 if (asc.alwaysAdd(*this, E)) { 1109 autoCreateBlock(); 1110 appendStmt(Block, E); 1111 } 1112 return Block; 1113} 1114 1115CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1116 // "break" is a control-flow statement. Thus we stop processing the current 1117 // block. 1118 if (badCFG) 1119 return 0; 1120 1121 // Now create a new block that ends with the break statement. 1122 Block = createBlock(false); 1123 Block->setTerminator(B); 1124 1125 // If there is no target for the break, then we are looking at an incomplete 1126 // AST. This means that the CFG cannot be constructed. 1127 if (BreakJumpTarget.block) { 1128 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1129 addSuccessor(Block, BreakJumpTarget.block); 1130 } else 1131 badCFG = true; 1132 1133 1134 return Block; 1135} 1136 1137static bool CanThrow(Expr *E, ASTContext &Ctx) { 1138 QualType Ty = E->getType(); 1139 if (Ty->isFunctionPointerType()) 1140 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1141 else if (Ty->isBlockPointerType()) 1142 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1143 1144 const FunctionType *FT = Ty->getAs<FunctionType>(); 1145 if (FT) { 1146 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1147 if (Proto->isNothrow(Ctx)) 1148 return false; 1149 } 1150 return true; 1151} 1152 1153CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1154 // Compute the callee type. 1155 QualType calleeType = C->getCallee()->getType(); 1156 if (calleeType == Context->BoundMemberTy) { 1157 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1158 1159 // We should only get a null bound type if processing a dependent 1160 // CFG. Recover by assuming nothing. 1161 if (!boundType.isNull()) calleeType = boundType; 1162 } 1163 1164 // If this is a call to a no-return function, this stops the block here. 1165 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1166 1167 bool AddEHEdge = false; 1168 1169 // Languages without exceptions are assumed to not throw. 1170 if (Context->getLangOptions().Exceptions) { 1171 if (BuildOpts.AddEHEdges) 1172 AddEHEdge = true; 1173 } 1174 1175 if (FunctionDecl *FD = C->getDirectCallee()) { 1176 if (FD->hasAttr<NoReturnAttr>()) 1177 NoReturn = true; 1178 if (FD->hasAttr<NoThrowAttr>()) 1179 AddEHEdge = false; 1180 } 1181 1182 if (!CanThrow(C->getCallee(), *Context)) 1183 AddEHEdge = false; 1184 1185 if (!NoReturn && !AddEHEdge) 1186 return VisitStmt(C, asc.withAlwaysAdd(true)); 1187 1188 if (Block) { 1189 Succ = Block; 1190 if (badCFG) 1191 return 0; 1192 } 1193 1194 Block = createBlock(!NoReturn); 1195 appendStmt(Block, C); 1196 1197 if (NoReturn) { 1198 // Wire this to the exit block directly. 1199 addSuccessor(Block, &cfg->getExit()); 1200 } 1201 if (AddEHEdge) { 1202 // Add exceptional edges. 1203 if (TryTerminatedBlock) 1204 addSuccessor(Block, TryTerminatedBlock); 1205 else 1206 addSuccessor(Block, &cfg->getExit()); 1207 } 1208 1209 return VisitChildren(C); 1210} 1211 1212CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1213 AddStmtChoice asc) { 1214 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1215 appendStmt(ConfluenceBlock, C); 1216 if (badCFG) 1217 return 0; 1218 1219 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1220 Succ = ConfluenceBlock; 1221 Block = NULL; 1222 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1223 if (badCFG) 1224 return 0; 1225 1226 Succ = ConfluenceBlock; 1227 Block = NULL; 1228 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1229 if (badCFG) 1230 return 0; 1231 1232 Block = createBlock(false); 1233 // See if this is a known constant. 1234 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1235 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1236 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1237 Block->setTerminator(C); 1238 return addStmt(C->getCond()); 1239} 1240 1241 1242CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1243 addLocalScopeAndDtors(C); 1244 CFGBlock* LastBlock = Block; 1245 1246 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1247 I != E; ++I ) { 1248 // If we hit a segment of code just containing ';' (NullStmts), we can 1249 // get a null block back. In such cases, just use the LastBlock 1250 if (CFGBlock *newBlock = addStmt(*I)) 1251 LastBlock = newBlock; 1252 1253 if (badCFG) 1254 return NULL; 1255 } 1256 1257 return LastBlock; 1258} 1259 1260CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1261 AddStmtChoice asc) { 1262 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1263 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1264 1265 // Create the confluence block that will "merge" the results of the ternary 1266 // expression. 1267 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1268 appendStmt(ConfluenceBlock, C); 1269 if (badCFG) 1270 return 0; 1271 1272 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1273 1274 // Create a block for the LHS expression if there is an LHS expression. A 1275 // GCC extension allows LHS to be NULL, causing the condition to be the 1276 // value that is returned instead. 1277 // e.g: x ?: y is shorthand for: x ? x : y; 1278 Succ = ConfluenceBlock; 1279 Block = NULL; 1280 CFGBlock* LHSBlock = 0; 1281 const Expr *trueExpr = C->getTrueExpr(); 1282 if (trueExpr != opaqueValue) { 1283 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1284 if (badCFG) 1285 return 0; 1286 Block = NULL; 1287 } 1288 else 1289 LHSBlock = ConfluenceBlock; 1290 1291 // Create the block for the RHS expression. 1292 Succ = ConfluenceBlock; 1293 CFGBlock* RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1294 if (badCFG) 1295 return 0; 1296 1297 // Create the block that will contain the condition. 1298 Block = createBlock(false); 1299 1300 // See if this is a known constant. 1301 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1302 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1303 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1304 Block->setTerminator(C); 1305 Expr *condExpr = C->getCond(); 1306 1307 if (opaqueValue) { 1308 // Run the condition expression if it's not trivially expressed in 1309 // terms of the opaque value (or if there is no opaque value). 1310 if (condExpr != opaqueValue) 1311 addStmt(condExpr); 1312 1313 // Before that, run the common subexpression if there was one. 1314 // At least one of this or the above will be run. 1315 return addStmt(BCO->getCommon()); 1316 } 1317 1318 return addStmt(condExpr); 1319} 1320 1321CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1322 // Check if the Decl is for an __label__. If so, elide it from the 1323 // CFG entirely. 1324 if (isa<LabelDecl>(*DS->decl_begin())) 1325 return Block; 1326 1327 // This case also handles static_asserts. 1328 if (DS->isSingleDecl()) 1329 return VisitDeclSubExpr(DS); 1330 1331 CFGBlock *B = 0; 1332 1333 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1334 typedef llvm::SmallVector<Decl*,10> BufTy; 1335 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1336 1337 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1338 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1339 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1340 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1341 1342 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1343 // automatically freed with the CFG. 1344 DeclGroupRef DG(*I); 1345 Decl *D = *I; 1346 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1347 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1348 1349 // Append the fake DeclStmt to block. 1350 B = VisitDeclSubExpr(DSNew); 1351 } 1352 1353 return B; 1354} 1355 1356/// VisitDeclSubExpr - Utility method to add block-level expressions for 1357/// DeclStmts and initializers in them. 1358CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1359 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1360 Decl *D = DS->getSingleDecl(); 1361 1362 if (isa<StaticAssertDecl>(D)) { 1363 // static_asserts aren't added to the CFG because they do not impact 1364 // runtime semantics. 1365 return Block; 1366 } 1367 1368 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1369 1370 if (!VD) { 1371 autoCreateBlock(); 1372 appendStmt(Block, DS); 1373 return Block; 1374 } 1375 1376 bool IsReference = false; 1377 bool HasTemporaries = false; 1378 1379 // Destructors of temporaries in initialization expression should be called 1380 // after initialization finishes. 1381 Expr *Init = VD->getInit(); 1382 if (Init) { 1383 IsReference = VD->getType()->isReferenceType(); 1384 HasTemporaries = isa<ExprWithCleanups>(Init); 1385 1386 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1387 // Generate destructors for temporaries in initialization expression. 1388 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1389 IsReference); 1390 } 1391 } 1392 1393 autoCreateBlock(); 1394 appendStmt(Block, DS); 1395 1396 if (Init) { 1397 if (HasTemporaries) 1398 // For expression with temporaries go directly to subexpression to omit 1399 // generating destructors for the second time. 1400 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1401 else 1402 Visit(Init); 1403 } 1404 1405 // If the type of VD is a VLA, then we must process its size expressions. 1406 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1407 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1408 Block = addStmt(VA->getSizeExpr()); 1409 1410 // Remove variable from local scope. 1411 if (ScopePos && VD == *ScopePos) 1412 ++ScopePos; 1413 1414 return Block; 1415} 1416 1417CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1418 // We may see an if statement in the middle of a basic block, or it may be the 1419 // first statement we are processing. In either case, we create a new basic 1420 // block. First, we create the blocks for the then...else statements, and 1421 // then we create the block containing the if statement. If we were in the 1422 // middle of a block, we stop processing that block. That block is then the 1423 // implicit successor for the "then" and "else" clauses. 1424 1425 // Save local scope position because in case of condition variable ScopePos 1426 // won't be restored when traversing AST. 1427 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1428 1429 // Create local scope for possible condition variable. 1430 // Store scope position. Add implicit destructor. 1431 if (VarDecl* VD = I->getConditionVariable()) { 1432 LocalScope::const_iterator BeginScopePos = ScopePos; 1433 addLocalScopeForVarDecl(VD); 1434 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1435 } 1436 1437 // The block we were processing is now finished. Make it the successor 1438 // block. 1439 if (Block) { 1440 Succ = Block; 1441 if (badCFG) 1442 return 0; 1443 } 1444 1445 // Process the false branch. 1446 CFGBlock* ElseBlock = Succ; 1447 1448 if (Stmt* Else = I->getElse()) { 1449 SaveAndRestore<CFGBlock*> sv(Succ); 1450 1451 // NULL out Block so that the recursive call to Visit will 1452 // create a new basic block. 1453 Block = NULL; 1454 1455 // If branch is not a compound statement create implicit scope 1456 // and add destructors. 1457 if (!isa<CompoundStmt>(Else)) 1458 addLocalScopeAndDtors(Else); 1459 1460 ElseBlock = addStmt(Else); 1461 1462 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1463 ElseBlock = sv.get(); 1464 else if (Block) { 1465 if (badCFG) 1466 return 0; 1467 } 1468 } 1469 1470 // Process the true branch. 1471 CFGBlock* ThenBlock; 1472 { 1473 Stmt* Then = I->getThen(); 1474 assert(Then); 1475 SaveAndRestore<CFGBlock*> sv(Succ); 1476 Block = NULL; 1477 1478 // If branch is not a compound statement create implicit scope 1479 // and add destructors. 1480 if (!isa<CompoundStmt>(Then)) 1481 addLocalScopeAndDtors(Then); 1482 1483 ThenBlock = addStmt(Then); 1484 1485 if (!ThenBlock) { 1486 // We can reach here if the "then" body has all NullStmts. 1487 // Create an empty block so we can distinguish between true and false 1488 // branches in path-sensitive analyses. 1489 ThenBlock = createBlock(false); 1490 addSuccessor(ThenBlock, sv.get()); 1491 } else if (Block) { 1492 if (badCFG) 1493 return 0; 1494 } 1495 } 1496 1497 // Now create a new block containing the if statement. 1498 Block = createBlock(false); 1499 1500 // Set the terminator of the new block to the If statement. 1501 Block->setTerminator(I); 1502 1503 // See if this is a known constant. 1504 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1505 1506 // Now add the successors. 1507 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1508 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1509 1510 // Add the condition as the last statement in the new block. This may create 1511 // new blocks as the condition may contain control-flow. Any newly created 1512 // blocks will be pointed to be "Block". 1513 Block = addStmt(I->getCond()); 1514 1515 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1516 // and the condition variable initialization to the CFG. 1517 if (VarDecl *VD = I->getConditionVariable()) { 1518 if (Expr *Init = VD->getInit()) { 1519 autoCreateBlock(); 1520 appendStmt(Block, I->getConditionVariableDeclStmt()); 1521 addStmt(Init); 1522 } 1523 } 1524 1525 return Block; 1526} 1527 1528 1529CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1530 // If we were in the middle of a block we stop processing that block. 1531 // 1532 // NOTE: If a "return" appears in the middle of a block, this means that the 1533 // code afterwards is DEAD (unreachable). We still keep a basic block 1534 // for that code; a simple "mark-and-sweep" from the entry block will be 1535 // able to report such dead blocks. 1536 1537 // Create the new block. 1538 Block = createBlock(false); 1539 1540 // The Exit block is the only successor. 1541 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1542 addSuccessor(Block, &cfg->getExit()); 1543 1544 // Add the return statement to the block. This may create new blocks if R 1545 // contains control-flow (short-circuit operations). 1546 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1547} 1548 1549CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1550 // Get the block of the labeled statement. Add it to our map. 1551 addStmt(L->getSubStmt()); 1552 CFGBlock *LabelBlock = Block; 1553 1554 if (!LabelBlock) // This can happen when the body is empty, i.e. 1555 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1556 1557 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1558 "label already in map"); 1559 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1560 1561 // Labels partition blocks, so this is the end of the basic block we were 1562 // processing (L is the block's label). Because this is label (and we have 1563 // already processed the substatement) there is no extra control-flow to worry 1564 // about. 1565 LabelBlock->setLabel(L); 1566 if (badCFG) 1567 return 0; 1568 1569 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1570 Block = NULL; 1571 1572 // This block is now the implicit successor of other blocks. 1573 Succ = LabelBlock; 1574 1575 return LabelBlock; 1576} 1577 1578CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1579 // Goto is a control-flow statement. Thus we stop processing the current 1580 // block and create a new one. 1581 1582 Block = createBlock(false); 1583 Block->setTerminator(G); 1584 1585 // If we already know the mapping to the label block add the successor now. 1586 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1587 1588 if (I == LabelMap.end()) 1589 // We will need to backpatch this block later. 1590 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1591 else { 1592 JumpTarget JT = I->second; 1593 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1594 addSuccessor(Block, JT.block); 1595 } 1596 1597 return Block; 1598} 1599 1600CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1601 CFGBlock* LoopSuccessor = NULL; 1602 1603 // Save local scope position because in case of condition variable ScopePos 1604 // won't be restored when traversing AST. 1605 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1606 1607 // Create local scope for init statement and possible condition variable. 1608 // Add destructor for init statement and condition variable. 1609 // Store scope position for continue statement. 1610 if (Stmt* Init = F->getInit()) 1611 addLocalScopeForStmt(Init); 1612 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1613 1614 if (VarDecl* VD = F->getConditionVariable()) 1615 addLocalScopeForVarDecl(VD); 1616 LocalScope::const_iterator ContinueScopePos = ScopePos; 1617 1618 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1619 1620 // "for" is a control-flow statement. Thus we stop processing the current 1621 // block. 1622 if (Block) { 1623 if (badCFG) 1624 return 0; 1625 LoopSuccessor = Block; 1626 } else 1627 LoopSuccessor = Succ; 1628 1629 // Save the current value for the break targets. 1630 // All breaks should go to the code following the loop. 1631 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1632 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1633 1634 // Because of short-circuit evaluation, the condition of the loop can span 1635 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1636 // evaluate the condition. 1637 CFGBlock* ExitConditionBlock = createBlock(false); 1638 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1639 1640 // Set the terminator for the "exit" condition block. 1641 ExitConditionBlock->setTerminator(F); 1642 1643 // Now add the actual condition to the condition block. Because the condition 1644 // itself may contain control-flow, new blocks may be created. 1645 if (Stmt* C = F->getCond()) { 1646 Block = ExitConditionBlock; 1647 EntryConditionBlock = addStmt(C); 1648 if (badCFG) 1649 return 0; 1650 assert(Block == EntryConditionBlock || 1651 (Block == 0 && EntryConditionBlock == Succ)); 1652 1653 // If this block contains a condition variable, add both the condition 1654 // variable and initializer to the CFG. 1655 if (VarDecl *VD = F->getConditionVariable()) { 1656 if (Expr *Init = VD->getInit()) { 1657 autoCreateBlock(); 1658 appendStmt(Block, F->getConditionVariableDeclStmt()); 1659 EntryConditionBlock = addStmt(Init); 1660 assert(Block == EntryConditionBlock); 1661 } 1662 } 1663 1664 if (Block) { 1665 if (badCFG) 1666 return 0; 1667 } 1668 } 1669 1670 // The condition block is the implicit successor for the loop body as well as 1671 // any code above the loop. 1672 Succ = EntryConditionBlock; 1673 1674 // See if this is a known constant. 1675 TryResult KnownVal(true); 1676 1677 if (F->getCond()) 1678 KnownVal = tryEvaluateBool(F->getCond()); 1679 1680 // Now create the loop body. 1681 { 1682 assert(F->getBody()); 1683 1684 // Save the current values for Block, Succ, and continue targets. 1685 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1686 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1687 1688 // Create a new block to contain the (bottom) of the loop body. 1689 Block = NULL; 1690 1691 // Loop body should end with destructor of Condition variable (if any). 1692 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1693 1694 if (Stmt* I = F->getInc()) { 1695 // Generate increment code in its own basic block. This is the target of 1696 // continue statements. 1697 Succ = addStmt(I); 1698 } else { 1699 // No increment code. Create a special, empty, block that is used as the 1700 // target block for "looping back" to the start of the loop. 1701 assert(Succ == EntryConditionBlock); 1702 Succ = Block ? Block : createBlock(); 1703 } 1704 1705 // Finish up the increment (or empty) block if it hasn't been already. 1706 if (Block) { 1707 assert(Block == Succ); 1708 if (badCFG) 1709 return 0; 1710 Block = 0; 1711 } 1712 1713 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1714 1715 // The starting block for the loop increment is the block that should 1716 // represent the 'loop target' for looping back to the start of the loop. 1717 ContinueJumpTarget.block->setLoopTarget(F); 1718 1719 // If body is not a compound statement create implicit scope 1720 // and add destructors. 1721 if (!isa<CompoundStmt>(F->getBody())) 1722 addLocalScopeAndDtors(F->getBody()); 1723 1724 // Now populate the body block, and in the process create new blocks as we 1725 // walk the body of the loop. 1726 CFGBlock* BodyBlock = addStmt(F->getBody()); 1727 1728 if (!BodyBlock) 1729 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1730 else if (badCFG) 1731 return 0; 1732 1733 // This new body block is a successor to our "exit" condition block. 1734 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1735 } 1736 1737 // Link up the condition block with the code that follows the loop. (the 1738 // false branch). 1739 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1740 1741 // If the loop contains initialization, create a new block for those 1742 // statements. This block can also contain statements that precede the loop. 1743 if (Stmt* I = F->getInit()) { 1744 Block = createBlock(); 1745 return addStmt(I); 1746 } 1747 1748 // There is no loop initialization. We are thus basically a while loop. 1749 // NULL out Block to force lazy block construction. 1750 Block = NULL; 1751 Succ = EntryConditionBlock; 1752 return EntryConditionBlock; 1753} 1754 1755CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1756 if (asc.alwaysAdd(*this, M)) { 1757 autoCreateBlock(); 1758 appendStmt(Block, M); 1759 } 1760 return Visit(M->getBase()); 1761} 1762 1763CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1764 // Objective-C fast enumeration 'for' statements: 1765 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1766 // 1767 // for ( Type newVariable in collection_expression ) { statements } 1768 // 1769 // becomes: 1770 // 1771 // prologue: 1772 // 1. collection_expression 1773 // T. jump to loop_entry 1774 // loop_entry: 1775 // 1. side-effects of element expression 1776 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1777 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1778 // TB: 1779 // statements 1780 // T. jump to loop_entry 1781 // FB: 1782 // what comes after 1783 // 1784 // and 1785 // 1786 // Type existingItem; 1787 // for ( existingItem in expression ) { statements } 1788 // 1789 // becomes: 1790 // 1791 // the same with newVariable replaced with existingItem; the binding works 1792 // the same except that for one ObjCForCollectionStmt::getElement() returns 1793 // a DeclStmt and the other returns a DeclRefExpr. 1794 // 1795 1796 CFGBlock* LoopSuccessor = 0; 1797 1798 if (Block) { 1799 if (badCFG) 1800 return 0; 1801 LoopSuccessor = Block; 1802 Block = 0; 1803 } else 1804 LoopSuccessor = Succ; 1805 1806 // Build the condition blocks. 1807 CFGBlock* ExitConditionBlock = createBlock(false); 1808 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1809 1810 // Set the terminator for the "exit" condition block. 1811 ExitConditionBlock->setTerminator(S); 1812 1813 // The last statement in the block should be the ObjCForCollectionStmt, which 1814 // performs the actual binding to 'element' and determines if there are any 1815 // more items in the collection. 1816 appendStmt(ExitConditionBlock, S); 1817 Block = ExitConditionBlock; 1818 1819 // Walk the 'element' expression to see if there are any side-effects. We 1820 // generate new blocks as necessary. We DON'T add the statement by default to 1821 // the CFG unless it contains control-flow. 1822 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1823 if (Block) { 1824 if (badCFG) 1825 return 0; 1826 Block = 0; 1827 } 1828 1829 // The condition block is the implicit successor for the loop body as well as 1830 // any code above the loop. 1831 Succ = EntryConditionBlock; 1832 1833 // Now create the true branch. 1834 { 1835 // Save the current values for Succ, continue and break targets. 1836 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1837 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1838 save_break(BreakJumpTarget); 1839 1840 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1841 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1842 1843 CFGBlock* BodyBlock = addStmt(S->getBody()); 1844 1845 if (!BodyBlock) 1846 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1847 else if (Block) { 1848 if (badCFG) 1849 return 0; 1850 } 1851 1852 // This new body block is a successor to our "exit" condition block. 1853 addSuccessor(ExitConditionBlock, BodyBlock); 1854 } 1855 1856 // Link up the condition block with the code that follows the loop. 1857 // (the false branch). 1858 addSuccessor(ExitConditionBlock, LoopSuccessor); 1859 1860 // Now create a prologue block to contain the collection expression. 1861 Block = createBlock(); 1862 return addStmt(S->getCollection()); 1863} 1864 1865CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1866 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1867 1868 // Inline the body. 1869 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1870 1871 // The sync body starts its own basic block. This makes it a little easier 1872 // for diagnostic clients. 1873 if (SyncBlock) { 1874 if (badCFG) 1875 return 0; 1876 1877 Block = 0; 1878 Succ = SyncBlock; 1879 } 1880 1881 // Add the @synchronized to the CFG. 1882 autoCreateBlock(); 1883 appendStmt(Block, S); 1884 1885 // Inline the sync expression. 1886 return addStmt(S->getSynchExpr()); 1887} 1888 1889CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1890 // FIXME 1891 return NYS(); 1892} 1893 1894CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1895 CFGBlock* LoopSuccessor = NULL; 1896 1897 // Save local scope position because in case of condition variable ScopePos 1898 // won't be restored when traversing AST. 1899 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1900 1901 // Create local scope for possible condition variable. 1902 // Store scope position for continue statement. 1903 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1904 if (VarDecl* VD = W->getConditionVariable()) { 1905 addLocalScopeForVarDecl(VD); 1906 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1907 } 1908 1909 // "while" is a control-flow statement. Thus we stop processing the current 1910 // block. 1911 if (Block) { 1912 if (badCFG) 1913 return 0; 1914 LoopSuccessor = Block; 1915 Block = 0; 1916 } else 1917 LoopSuccessor = Succ; 1918 1919 // Because of short-circuit evaluation, the condition of the loop can span 1920 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1921 // evaluate the condition. 1922 CFGBlock* ExitConditionBlock = createBlock(false); 1923 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1924 1925 // Set the terminator for the "exit" condition block. 1926 ExitConditionBlock->setTerminator(W); 1927 1928 // Now add the actual condition to the condition block. Because the condition 1929 // itself may contain control-flow, new blocks may be created. Thus we update 1930 // "Succ" after adding the condition. 1931 if (Stmt* C = W->getCond()) { 1932 Block = ExitConditionBlock; 1933 EntryConditionBlock = addStmt(C); 1934 // The condition might finish the current 'Block'. 1935 Block = EntryConditionBlock; 1936 1937 // If this block contains a condition variable, add both the condition 1938 // variable and initializer to the CFG. 1939 if (VarDecl *VD = W->getConditionVariable()) { 1940 if (Expr *Init = VD->getInit()) { 1941 autoCreateBlock(); 1942 appendStmt(Block, W->getConditionVariableDeclStmt()); 1943 EntryConditionBlock = addStmt(Init); 1944 assert(Block == EntryConditionBlock); 1945 } 1946 } 1947 1948 if (Block) { 1949 if (badCFG) 1950 return 0; 1951 } 1952 } 1953 1954 // The condition block is the implicit successor for the loop body as well as 1955 // any code above the loop. 1956 Succ = EntryConditionBlock; 1957 1958 // See if this is a known constant. 1959 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1960 1961 // Process the loop body. 1962 { 1963 assert(W->getBody()); 1964 1965 // Save the current values for Block, Succ, and continue and break targets 1966 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1967 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1968 save_break(BreakJumpTarget); 1969 1970 // Create an empty block to represent the transition block for looping back 1971 // to the head of the loop. 1972 Block = 0; 1973 assert(Succ == EntryConditionBlock); 1974 Succ = createBlock(); 1975 Succ->setLoopTarget(W); 1976 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1977 1978 // All breaks should go to the code following the loop. 1979 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1980 1981 // NULL out Block to force lazy instantiation of blocks for the body. 1982 Block = NULL; 1983 1984 // Loop body should end with destructor of Condition variable (if any). 1985 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1986 1987 // If body is not a compound statement create implicit scope 1988 // and add destructors. 1989 if (!isa<CompoundStmt>(W->getBody())) 1990 addLocalScopeAndDtors(W->getBody()); 1991 1992 // Create the body. The returned block is the entry to the loop body. 1993 CFGBlock* BodyBlock = addStmt(W->getBody()); 1994 1995 if (!BodyBlock) 1996 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 1997 else if (Block) { 1998 if (badCFG) 1999 return 0; 2000 } 2001 2002 // Add the loop body entry as a successor to the condition. 2003 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2004 } 2005 2006 // Link up the condition block with the code that follows the loop. (the 2007 // false branch). 2008 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2009 2010 // There can be no more statements in the condition block since we loop back 2011 // to this block. NULL out Block to force lazy creation of another block. 2012 Block = NULL; 2013 2014 // Return the condition block, which is the dominating block for the loop. 2015 Succ = EntryConditionBlock; 2016 return EntryConditionBlock; 2017} 2018 2019 2020CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 2021 // FIXME: For now we pretend that @catch and the code it contains does not 2022 // exit. 2023 return Block; 2024} 2025 2026CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 2027 // FIXME: This isn't complete. We basically treat @throw like a return 2028 // statement. 2029 2030 // If we were in the middle of a block we stop processing that block. 2031 if (badCFG) 2032 return 0; 2033 2034 // Create the new block. 2035 Block = createBlock(false); 2036 2037 // The Exit block is the only successor. 2038 addSuccessor(Block, &cfg->getExit()); 2039 2040 // Add the statement to the block. This may create new blocks if S contains 2041 // control-flow (short-circuit operations). 2042 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2043} 2044 2045CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 2046 // If we were in the middle of a block we stop processing that block. 2047 if (badCFG) 2048 return 0; 2049 2050 // Create the new block. 2051 Block = createBlock(false); 2052 2053 if (TryTerminatedBlock) 2054 // The current try statement is the only successor. 2055 addSuccessor(Block, TryTerminatedBlock); 2056 else 2057 // otherwise the Exit block is the only successor. 2058 addSuccessor(Block, &cfg->getExit()); 2059 2060 // Add the statement to the block. This may create new blocks if S contains 2061 // control-flow (short-circuit operations). 2062 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2063} 2064 2065CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 2066 CFGBlock* LoopSuccessor = NULL; 2067 2068 // "do...while" is a control-flow statement. Thus we stop processing the 2069 // current block. 2070 if (Block) { 2071 if (badCFG) 2072 return 0; 2073 LoopSuccessor = Block; 2074 } else 2075 LoopSuccessor = Succ; 2076 2077 // Because of short-circuit evaluation, the condition of the loop can span 2078 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2079 // evaluate the condition. 2080 CFGBlock* ExitConditionBlock = createBlock(false); 2081 CFGBlock* EntryConditionBlock = ExitConditionBlock; 2082 2083 // Set the terminator for the "exit" condition block. 2084 ExitConditionBlock->setTerminator(D); 2085 2086 // Now add the actual condition to the condition block. Because the condition 2087 // itself may contain control-flow, new blocks may be created. 2088 if (Stmt* C = D->getCond()) { 2089 Block = ExitConditionBlock; 2090 EntryConditionBlock = addStmt(C); 2091 if (Block) { 2092 if (badCFG) 2093 return 0; 2094 } 2095 } 2096 2097 // The condition block is the implicit successor for the loop body. 2098 Succ = EntryConditionBlock; 2099 2100 // See if this is a known constant. 2101 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2102 2103 // Process the loop body. 2104 CFGBlock* BodyBlock = NULL; 2105 { 2106 assert(D->getBody()); 2107 2108 // Save the current values for Block, Succ, and continue and break targets 2109 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2110 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2111 save_break(BreakJumpTarget); 2112 2113 // All continues within this loop should go to the condition block 2114 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2115 2116 // All breaks should go to the code following the loop. 2117 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2118 2119 // NULL out Block to force lazy instantiation of blocks for the body. 2120 Block = NULL; 2121 2122 // If body is not a compound statement create implicit scope 2123 // and add destructors. 2124 if (!isa<CompoundStmt>(D->getBody())) 2125 addLocalScopeAndDtors(D->getBody()); 2126 2127 // Create the body. The returned block is the entry to the loop body. 2128 BodyBlock = addStmt(D->getBody()); 2129 2130 if (!BodyBlock) 2131 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2132 else if (Block) { 2133 if (badCFG) 2134 return 0; 2135 } 2136 2137 if (!KnownVal.isFalse()) { 2138 // Add an intermediate block between the BodyBlock and the 2139 // ExitConditionBlock to represent the "loop back" transition. Create an 2140 // empty block to represent the transition block for looping back to the 2141 // head of the loop. 2142 // FIXME: Can we do this more efficiently without adding another block? 2143 Block = NULL; 2144 Succ = BodyBlock; 2145 CFGBlock *LoopBackBlock = createBlock(); 2146 LoopBackBlock->setLoopTarget(D); 2147 2148 // Add the loop body entry as a successor to the condition. 2149 addSuccessor(ExitConditionBlock, LoopBackBlock); 2150 } 2151 else 2152 addSuccessor(ExitConditionBlock, NULL); 2153 } 2154 2155 // Link up the condition block with the code that follows the loop. 2156 // (the false branch). 2157 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2158 2159 // There can be no more statements in the body block(s) since we loop back to 2160 // the body. NULL out Block to force lazy creation of another block. 2161 Block = NULL; 2162 2163 // Return the loop body, which is the dominating block for the loop. 2164 Succ = BodyBlock; 2165 return BodyBlock; 2166} 2167 2168CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2169 // "continue" is a control-flow statement. Thus we stop processing the 2170 // current block. 2171 if (badCFG) 2172 return 0; 2173 2174 // Now create a new block that ends with the continue statement. 2175 Block = createBlock(false); 2176 Block->setTerminator(C); 2177 2178 // If there is no target for the continue, then we are looking at an 2179 // incomplete AST. This means the CFG cannot be constructed. 2180 if (ContinueJumpTarget.block) { 2181 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2182 addSuccessor(Block, ContinueJumpTarget.block); 2183 } else 2184 badCFG = true; 2185 2186 return Block; 2187} 2188 2189CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2190 AddStmtChoice asc) { 2191 2192 if (asc.alwaysAdd(*this, E)) { 2193 autoCreateBlock(); 2194 appendStmt(Block, E); 2195 } 2196 2197 // VLA types have expressions that must be evaluated. 2198 CFGBlock *lastBlock = Block; 2199 2200 if (E->isArgumentType()) { 2201 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2202 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2203 lastBlock = addStmt(VA->getSizeExpr()); 2204 } 2205 2206 return lastBlock; 2207} 2208 2209/// VisitStmtExpr - Utility method to handle (nested) statement 2210/// expressions (a GCC extension). 2211CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2212 if (asc.alwaysAdd(*this, SE)) { 2213 autoCreateBlock(); 2214 appendStmt(Block, SE); 2215 } 2216 return VisitCompoundStmt(SE->getSubStmt()); 2217} 2218 2219CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2220 // "switch" is a control-flow statement. Thus we stop processing the current 2221 // block. 2222 CFGBlock* SwitchSuccessor = NULL; 2223 2224 // Save local scope position because in case of condition variable ScopePos 2225 // won't be restored when traversing AST. 2226 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2227 2228 // Create local scope for possible condition variable. 2229 // Store scope position. Add implicit destructor. 2230 if (VarDecl* VD = Terminator->getConditionVariable()) { 2231 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2232 addLocalScopeForVarDecl(VD); 2233 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2234 } 2235 2236 if (Block) { 2237 if (badCFG) 2238 return 0; 2239 SwitchSuccessor = Block; 2240 } else SwitchSuccessor = Succ; 2241 2242 // Save the current "switch" context. 2243 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2244 save_default(DefaultCaseBlock); 2245 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2246 2247 // Set the "default" case to be the block after the switch statement. If the 2248 // switch statement contains a "default:", this value will be overwritten with 2249 // the block for that code. 2250 DefaultCaseBlock = SwitchSuccessor; 2251 2252 // Create a new block that will contain the switch statement. 2253 SwitchTerminatedBlock = createBlock(false); 2254 2255 // Now process the switch body. The code after the switch is the implicit 2256 // successor. 2257 Succ = SwitchSuccessor; 2258 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2259 2260 // When visiting the body, the case statements should automatically get linked 2261 // up to the switch. We also don't keep a pointer to the body, since all 2262 // control-flow from the switch goes to case/default statements. 2263 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2264 Block = NULL; 2265 2266 // For pruning unreachable case statements, save the current state 2267 // for tracking the condition value. 2268 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2269 false); 2270 2271 // Determine if the switch condition can be explicitly evaluated. 2272 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2273 Expr::EvalResult result; 2274 bool b = tryEvaluate(Terminator->getCond(), result); 2275 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2276 b ? &result : 0); 2277 2278 // If body is not a compound statement create implicit scope 2279 // and add destructors. 2280 if (!isa<CompoundStmt>(Terminator->getBody())) 2281 addLocalScopeAndDtors(Terminator->getBody()); 2282 2283 addStmt(Terminator->getBody()); 2284 if (Block) { 2285 if (badCFG) 2286 return 0; 2287 } 2288 2289 // If we have no "default:" case, the default transition is to the code 2290 // following the switch body. Moreover, take into account if all the 2291 // cases of a switch are covered (e.g., switching on an enum value). 2292 addSuccessor(SwitchTerminatedBlock, 2293 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2294 ? 0 : DefaultCaseBlock); 2295 2296 // Add the terminator and condition in the switch block. 2297 SwitchTerminatedBlock->setTerminator(Terminator); 2298 Block = SwitchTerminatedBlock; 2299 Block = addStmt(Terminator->getCond()); 2300 2301 // Finally, if the SwitchStmt contains a condition variable, add both the 2302 // SwitchStmt and the condition variable initialization to the CFG. 2303 if (VarDecl *VD = Terminator->getConditionVariable()) { 2304 if (Expr *Init = VD->getInit()) { 2305 autoCreateBlock(); 2306 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2307 addStmt(Init); 2308 } 2309 } 2310 2311 return Block; 2312} 2313 2314static bool shouldAddCase(bool &switchExclusivelyCovered, 2315 const Expr::EvalResult *switchCond, 2316 const CaseStmt *CS, 2317 ASTContext &Ctx) { 2318 if (!switchCond) 2319 return true; 2320 2321 bool addCase = false; 2322 2323 if (!switchExclusivelyCovered) { 2324 if (switchCond->Val.isInt()) { 2325 // Evaluate the LHS of the case value. 2326 Expr::EvalResult V1; 2327 CS->getLHS()->Evaluate(V1, Ctx); 2328 assert(V1.Val.isInt()); 2329 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2330 const llvm::APSInt &lhsInt = V1.Val.getInt(); 2331 2332 if (condInt == lhsInt) { 2333 addCase = true; 2334 switchExclusivelyCovered = true; 2335 } 2336 else if (condInt < lhsInt) { 2337 if (const Expr *RHS = CS->getRHS()) { 2338 // Evaluate the RHS of the case value. 2339 Expr::EvalResult V2; 2340 RHS->Evaluate(V2, Ctx); 2341 assert(V2.Val.isInt()); 2342 if (V2.Val.getInt() <= condInt) { 2343 addCase = true; 2344 switchExclusivelyCovered = true; 2345 } 2346 } 2347 } 2348 } 2349 else 2350 addCase = true; 2351 } 2352 return addCase; 2353} 2354 2355CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2356 // CaseStmts are essentially labels, so they are the first statement in a 2357 // block. 2358 CFGBlock *TopBlock = 0, *LastBlock = 0; 2359 2360 if (Stmt *Sub = CS->getSubStmt()) { 2361 // For deeply nested chains of CaseStmts, instead of doing a recursion 2362 // (which can blow out the stack), manually unroll and create blocks 2363 // along the way. 2364 while (isa<CaseStmt>(Sub)) { 2365 CFGBlock *currentBlock = createBlock(false); 2366 currentBlock->setLabel(CS); 2367 2368 if (TopBlock) 2369 addSuccessor(LastBlock, currentBlock); 2370 else 2371 TopBlock = currentBlock; 2372 2373 addSuccessor(SwitchTerminatedBlock, 2374 shouldAddCase(switchExclusivelyCovered, switchCond, 2375 CS, *Context) 2376 ? currentBlock : 0); 2377 2378 LastBlock = currentBlock; 2379 CS = cast<CaseStmt>(Sub); 2380 Sub = CS->getSubStmt(); 2381 } 2382 2383 addStmt(Sub); 2384 } 2385 2386 CFGBlock* CaseBlock = Block; 2387 if (!CaseBlock) 2388 CaseBlock = createBlock(); 2389 2390 // Cases statements partition blocks, so this is the top of the basic block we 2391 // were processing (the "case XXX:" is the label). 2392 CaseBlock->setLabel(CS); 2393 2394 if (badCFG) 2395 return 0; 2396 2397 // Add this block to the list of successors for the block with the switch 2398 // statement. 2399 assert(SwitchTerminatedBlock); 2400 addSuccessor(SwitchTerminatedBlock, 2401 shouldAddCase(switchExclusivelyCovered, switchCond, 2402 CS, *Context) 2403 ? CaseBlock : 0); 2404 2405 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2406 Block = NULL; 2407 2408 if (TopBlock) { 2409 addSuccessor(LastBlock, CaseBlock); 2410 Succ = TopBlock; 2411 } else { 2412 // This block is now the implicit successor of other blocks. 2413 Succ = CaseBlock; 2414 } 2415 2416 return Succ; 2417} 2418 2419CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2420 if (Terminator->getSubStmt()) 2421 addStmt(Terminator->getSubStmt()); 2422 2423 DefaultCaseBlock = Block; 2424 2425 if (!DefaultCaseBlock) 2426 DefaultCaseBlock = createBlock(); 2427 2428 // Default statements partition blocks, so this is the top of the basic block 2429 // we were processing (the "default:" is the label). 2430 DefaultCaseBlock->setLabel(Terminator); 2431 2432 if (badCFG) 2433 return 0; 2434 2435 // Unlike case statements, we don't add the default block to the successors 2436 // for the switch statement immediately. This is done when we finish 2437 // processing the switch statement. This allows for the default case 2438 // (including a fall-through to the code after the switch statement) to always 2439 // be the last successor of a switch-terminated block. 2440 2441 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2442 Block = NULL; 2443 2444 // This block is now the implicit successor of other blocks. 2445 Succ = DefaultCaseBlock; 2446 2447 return DefaultCaseBlock; 2448} 2449 2450CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2451 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2452 // current block. 2453 CFGBlock* TrySuccessor = NULL; 2454 2455 if (Block) { 2456 if (badCFG) 2457 return 0; 2458 TrySuccessor = Block; 2459 } else TrySuccessor = Succ; 2460 2461 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2462 2463 // Create a new block that will contain the try statement. 2464 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2465 // Add the terminator in the try block. 2466 NewTryTerminatedBlock->setTerminator(Terminator); 2467 2468 bool HasCatchAll = false; 2469 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2470 // The code after the try is the implicit successor. 2471 Succ = TrySuccessor; 2472 CXXCatchStmt *CS = Terminator->getHandler(h); 2473 if (CS->getExceptionDecl() == 0) { 2474 HasCatchAll = true; 2475 } 2476 Block = NULL; 2477 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2478 if (CatchBlock == 0) 2479 return 0; 2480 // Add this block to the list of successors for the block with the try 2481 // statement. 2482 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2483 } 2484 if (!HasCatchAll) { 2485 if (PrevTryTerminatedBlock) 2486 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2487 else 2488 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2489 } 2490 2491 // The code after the try is the implicit successor. 2492 Succ = TrySuccessor; 2493 2494 // Save the current "try" context. 2495 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2496 TryTerminatedBlock = NewTryTerminatedBlock; 2497 2498 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2499 Block = NULL; 2500 Block = addStmt(Terminator->getTryBlock()); 2501 return Block; 2502} 2503 2504CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2505 // CXXCatchStmt are treated like labels, so they are the first statement in a 2506 // block. 2507 2508 // Save local scope position because in case of exception variable ScopePos 2509 // won't be restored when traversing AST. 2510 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2511 2512 // Create local scope for possible exception variable. 2513 // Store scope position. Add implicit destructor. 2514 if (VarDecl* VD = CS->getExceptionDecl()) { 2515 LocalScope::const_iterator BeginScopePos = ScopePos; 2516 addLocalScopeForVarDecl(VD); 2517 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2518 } 2519 2520 if (CS->getHandlerBlock()) 2521 addStmt(CS->getHandlerBlock()); 2522 2523 CFGBlock* CatchBlock = Block; 2524 if (!CatchBlock) 2525 CatchBlock = createBlock(); 2526 2527 CatchBlock->setLabel(CS); 2528 2529 if (badCFG) 2530 return 0; 2531 2532 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2533 Block = NULL; 2534 2535 return CatchBlock; 2536} 2537 2538CFGBlock* CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt* S) { 2539 // C++0x for-range statements are specified as [stmt.ranged]: 2540 // 2541 // { 2542 // auto && __range = range-init; 2543 // for ( auto __begin = begin-expr, 2544 // __end = end-expr; 2545 // __begin != __end; 2546 // ++__begin ) { 2547 // for-range-declaration = *__begin; 2548 // statement 2549 // } 2550 // } 2551 2552 // Save local scope position before the addition of the implicit variables. 2553 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2554 2555 // Create local scopes and destructors for range, begin and end variables. 2556 if (Stmt *Range = S->getRangeStmt()) 2557 addLocalScopeForStmt(Range); 2558 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2559 addLocalScopeForStmt(BeginEnd); 2560 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2561 2562 LocalScope::const_iterator ContinueScopePos = ScopePos; 2563 2564 // "for" is a control-flow statement. Thus we stop processing the current 2565 // block. 2566 CFGBlock* LoopSuccessor = NULL; 2567 if (Block) { 2568 if (badCFG) 2569 return 0; 2570 LoopSuccessor = Block; 2571 } else 2572 LoopSuccessor = Succ; 2573 2574 // Save the current value for the break targets. 2575 // All breaks should go to the code following the loop. 2576 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2577 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2578 2579 // The block for the __begin != __end expression. 2580 CFGBlock* ConditionBlock = createBlock(false); 2581 ConditionBlock->setTerminator(S); 2582 2583 // Now add the actual condition to the condition block. 2584 if (Expr *C = S->getCond()) { 2585 Block = ConditionBlock; 2586 CFGBlock *BeginConditionBlock = addStmt(C); 2587 if (badCFG) 2588 return 0; 2589 assert(BeginConditionBlock == ConditionBlock && 2590 "condition block in for-range was unexpectedly complex"); 2591 (void)BeginConditionBlock; 2592 } 2593 2594 // The condition block is the implicit successor for the loop body as well as 2595 // any code above the loop. 2596 Succ = ConditionBlock; 2597 2598 // See if this is a known constant. 2599 TryResult KnownVal(true); 2600 2601 if (S->getCond()) 2602 KnownVal = tryEvaluateBool(S->getCond()); 2603 2604 // Now create the loop body. 2605 { 2606 assert(S->getBody()); 2607 2608 // Save the current values for Block, Succ, and continue targets. 2609 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2610 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2611 2612 // Generate increment code in its own basic block. This is the target of 2613 // continue statements. 2614 Block = 0; 2615 Succ = addStmt(S->getInc()); 2616 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2617 2618 // The starting block for the loop increment is the block that should 2619 // represent the 'loop target' for looping back to the start of the loop. 2620 ContinueJumpTarget.block->setLoopTarget(S); 2621 2622 // Finish up the increment block and prepare to start the loop body. 2623 assert(Block); 2624 if (badCFG) 2625 return 0; 2626 Block = 0; 2627 2628 2629 // Add implicit scope and dtors for loop variable. 2630 addLocalScopeAndDtors(S->getLoopVarStmt()); 2631 2632 // Populate a new block to contain the loop body and loop variable. 2633 Block = addStmt(S->getBody()); 2634 if (badCFG) 2635 return 0; 2636 Block = addStmt(S->getLoopVarStmt()); 2637 if (badCFG) 2638 return 0; 2639 2640 // This new body block is a successor to our condition block. 2641 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2642 } 2643 2644 // Link up the condition block with the code that follows the loop (the 2645 // false branch). 2646 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2647 2648 // Add the initialization statements. 2649 Block = createBlock(); 2650 addStmt(S->getBeginEndStmt()); 2651 return addStmt(S->getRangeStmt()); 2652} 2653 2654CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2655 AddStmtChoice asc) { 2656 if (BuildOpts.AddImplicitDtors) { 2657 // If adding implicit destructors visit the full expression for adding 2658 // destructors of temporaries. 2659 VisitForTemporaryDtors(E->getSubExpr()); 2660 2661 // Full expression has to be added as CFGStmt so it will be sequenced 2662 // before destructors of it's temporaries. 2663 asc = asc.withAlwaysAdd(true); 2664 } 2665 return Visit(E->getSubExpr(), asc); 2666} 2667 2668CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2669 AddStmtChoice asc) { 2670 if (asc.alwaysAdd(*this, E)) { 2671 autoCreateBlock(); 2672 appendStmt(Block, E); 2673 2674 // We do not want to propagate the AlwaysAdd property. 2675 asc = asc.withAlwaysAdd(false); 2676 } 2677 return Visit(E->getSubExpr(), asc); 2678} 2679 2680CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2681 AddStmtChoice asc) { 2682 autoCreateBlock(); 2683 if (!C->isElidable()) 2684 appendStmt(Block, C); 2685 2686 return VisitChildren(C); 2687} 2688 2689CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2690 AddStmtChoice asc) { 2691 if (asc.alwaysAdd(*this, E)) { 2692 autoCreateBlock(); 2693 appendStmt(Block, E); 2694 // We do not want to propagate the AlwaysAdd property. 2695 asc = asc.withAlwaysAdd(false); 2696 } 2697 return Visit(E->getSubExpr(), asc); 2698} 2699 2700CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2701 AddStmtChoice asc) { 2702 autoCreateBlock(); 2703 appendStmt(Block, C); 2704 return VisitChildren(C); 2705} 2706 2707CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2708 AddStmtChoice asc) { 2709 if (asc.alwaysAdd(*this, E)) { 2710 autoCreateBlock(); 2711 appendStmt(Block, E); 2712 } 2713 return Visit(E->getSubExpr(), AddStmtChoice()); 2714} 2715 2716CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2717 // Lazily create the indirect-goto dispatch block if there isn't one already. 2718 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2719 2720 if (!IBlock) { 2721 IBlock = createBlock(false); 2722 cfg->setIndirectGotoBlock(IBlock); 2723 } 2724 2725 // IndirectGoto is a control-flow statement. Thus we stop processing the 2726 // current block and create a new one. 2727 if (badCFG) 2728 return 0; 2729 2730 Block = createBlock(false); 2731 Block->setTerminator(I); 2732 addSuccessor(Block, IBlock); 2733 return addStmt(I->getTarget()); 2734} 2735 2736CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2737tryAgain: 2738 if (!E) { 2739 badCFG = true; 2740 return NULL; 2741 } 2742 switch (E->getStmtClass()) { 2743 default: 2744 return VisitChildrenForTemporaryDtors(E); 2745 2746 case Stmt::BinaryOperatorClass: 2747 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2748 2749 case Stmt::CXXBindTemporaryExprClass: 2750 return VisitCXXBindTemporaryExprForTemporaryDtors( 2751 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2752 2753 case Stmt::BinaryConditionalOperatorClass: 2754 case Stmt::ConditionalOperatorClass: 2755 return VisitConditionalOperatorForTemporaryDtors( 2756 cast<AbstractConditionalOperator>(E), BindToTemporary); 2757 2758 case Stmt::ImplicitCastExprClass: 2759 // For implicit cast we want BindToTemporary to be passed further. 2760 E = cast<CastExpr>(E)->getSubExpr(); 2761 goto tryAgain; 2762 2763 case Stmt::ParenExprClass: 2764 E = cast<ParenExpr>(E)->getSubExpr(); 2765 goto tryAgain; 2766 } 2767} 2768 2769CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2770 // When visiting children for destructors we want to visit them in reverse 2771 // order. Because there's no reverse iterator for children must to reverse 2772 // them in helper vector. 2773 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2774 ChildrenVect ChildrenRev; 2775 for (Stmt::child_range I = E->children(); I; ++I) { 2776 if (*I) ChildrenRev.push_back(*I); 2777 } 2778 2779 CFGBlock *B = Block; 2780 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2781 L = ChildrenRev.rend(); I != L; ++I) { 2782 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2783 B = R; 2784 } 2785 return B; 2786} 2787 2788CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2789 if (E->isLogicalOp()) { 2790 // Destructors for temporaries in LHS expression should be called after 2791 // those for RHS expression. Even if this will unnecessarily create a block, 2792 // this block will be used at least by the full expression. 2793 autoCreateBlock(); 2794 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2795 if (badCFG) 2796 return NULL; 2797 2798 Succ = ConfluenceBlock; 2799 Block = NULL; 2800 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2801 2802 if (RHSBlock) { 2803 if (badCFG) 2804 return NULL; 2805 2806 // If RHS expression did produce destructors we need to connect created 2807 // blocks to CFG in same manner as for binary operator itself. 2808 CFGBlock *LHSBlock = createBlock(false); 2809 LHSBlock->setTerminator(CFGTerminator(E, true)); 2810 2811 // For binary operator LHS block is before RHS in list of predecessors 2812 // of ConfluenceBlock. 2813 std::reverse(ConfluenceBlock->pred_begin(), 2814 ConfluenceBlock->pred_end()); 2815 2816 // See if this is a known constant. 2817 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2818 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2819 KnownVal.negate(); 2820 2821 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2822 // itself. 2823 if (E->getOpcode() == BO_LOr) { 2824 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2825 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2826 } else { 2827 assert (E->getOpcode() == BO_LAnd); 2828 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2829 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2830 } 2831 2832 Block = LHSBlock; 2833 return LHSBlock; 2834 } 2835 2836 Block = ConfluenceBlock; 2837 return ConfluenceBlock; 2838 } 2839 2840 if (E->isAssignmentOp()) { 2841 // For assignment operator (=) LHS expression is visited 2842 // before RHS expression. For destructors visit them in reverse order. 2843 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2844 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2845 return LHSBlock ? LHSBlock : RHSBlock; 2846 } 2847 2848 // For any other binary operator RHS expression is visited before 2849 // LHS expression (order of children). For destructors visit them in reverse 2850 // order. 2851 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2852 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2853 return RHSBlock ? RHSBlock : LHSBlock; 2854} 2855 2856CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2857 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2858 // First add destructors for temporaries in subexpression. 2859 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2860 if (!BindToTemporary) { 2861 // If lifetime of temporary is not prolonged (by assigning to constant 2862 // reference) add destructor for it. 2863 autoCreateBlock(); 2864 appendTemporaryDtor(Block, E); 2865 B = Block; 2866 } 2867 return B; 2868} 2869 2870CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2871 AbstractConditionalOperator *E, bool BindToTemporary) { 2872 // First add destructors for condition expression. Even if this will 2873 // unnecessarily create a block, this block will be used at least by the full 2874 // expression. 2875 autoCreateBlock(); 2876 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2877 if (badCFG) 2878 return NULL; 2879 if (BinaryConditionalOperator *BCO 2880 = dyn_cast<BinaryConditionalOperator>(E)) { 2881 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2882 if (badCFG) 2883 return NULL; 2884 } 2885 2886 // Try to add block with destructors for LHS expression. 2887 CFGBlock *LHSBlock = NULL; 2888 Succ = ConfluenceBlock; 2889 Block = NULL; 2890 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2891 if (badCFG) 2892 return NULL; 2893 2894 // Try to add block with destructors for RHS expression; 2895 Succ = ConfluenceBlock; 2896 Block = NULL; 2897 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2898 BindToTemporary); 2899 if (badCFG) 2900 return NULL; 2901 2902 if (!RHSBlock && !LHSBlock) { 2903 // If neither LHS nor RHS expression had temporaries to destroy don't create 2904 // more blocks. 2905 Block = ConfluenceBlock; 2906 return Block; 2907 } 2908 2909 Block = createBlock(false); 2910 Block->setTerminator(CFGTerminator(E, true)); 2911 2912 // See if this is a known constant. 2913 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2914 2915 if (LHSBlock) { 2916 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2917 } else if (KnownVal.isFalse()) { 2918 addSuccessor(Block, NULL); 2919 } else { 2920 addSuccessor(Block, ConfluenceBlock); 2921 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2922 } 2923 2924 if (!RHSBlock) 2925 RHSBlock = ConfluenceBlock; 2926 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2927 2928 return Block; 2929} 2930 2931} // end anonymous namespace 2932 2933/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2934/// no successors or predecessors. If this is the first block created in the 2935/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2936CFGBlock* CFG::createBlock() { 2937 bool first_block = begin() == end(); 2938 2939 // Create the block. 2940 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2941 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2942 Blocks.push_back(Mem, BlkBVC); 2943 2944 // If this is the first block, set it as the Entry and Exit. 2945 if (first_block) 2946 Entry = Exit = &back(); 2947 2948 // Return the block. 2949 return &back(); 2950} 2951 2952/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2953/// CFG is returned to the caller. 2954CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2955 const BuildOptions &BO) { 2956 CFGBuilder Builder(C, BO); 2957 return Builder.buildCFG(D, Statement); 2958} 2959 2960const CXXDestructorDecl * 2961CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 2962 switch (getKind()) { 2963 case CFGElement::Invalid: 2964 case CFGElement::Statement: 2965 case CFGElement::Initializer: 2966 llvm_unreachable("getDestructorDecl should only be used with " 2967 "ImplicitDtors"); 2968 case CFGElement::AutomaticObjectDtor: { 2969 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 2970 QualType ty = var->getType(); 2971 ty = ty.getNonReferenceType(); 2972 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 2973 ty = arrayType->getElementType(); 2974 } 2975 const RecordType *recordType = ty->getAs<RecordType>(); 2976 const CXXRecordDecl *classDecl = 2977 cast<CXXRecordDecl>(recordType->getDecl()); 2978 return classDecl->getDestructor(); 2979 } 2980 case CFGElement::TemporaryDtor: { 2981 const CXXBindTemporaryExpr *bindExpr = 2982 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 2983 const CXXTemporary *temp = bindExpr->getTemporary(); 2984 return temp->getDestructor(); 2985 } 2986 case CFGElement::BaseDtor: 2987 case CFGElement::MemberDtor: 2988 2989 // Not yet supported. 2990 return 0; 2991 } 2992 llvm_unreachable("getKind() returned bogus value"); 2993 return 0; 2994} 2995 2996bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 2997 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 2998 QualType ty = cdecl->getType(); 2999 return cast<FunctionType>(ty)->getNoReturnAttr(); 3000 } 3001 return false; 3002} 3003 3004//===----------------------------------------------------------------------===// 3005// CFG: Queries for BlkExprs. 3006//===----------------------------------------------------------------------===// 3007 3008namespace { 3009 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3010} 3011 3012static void FindSubExprAssignments(Stmt *S, 3013 llvm::SmallPtrSet<Expr*,50>& Set) { 3014 if (!S) 3015 return; 3016 3017 for (Stmt::child_range I = S->children(); I; ++I) { 3018 Stmt *child = *I; 3019 if (!child) 3020 continue; 3021 3022 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3023 if (B->isAssignmentOp()) Set.insert(B); 3024 3025 FindSubExprAssignments(child, Set); 3026 } 3027} 3028 3029static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3030 BlkExprMapTy* M = new BlkExprMapTy(); 3031 3032 // Look for assignments that are used as subexpressions. These are the only 3033 // assignments that we want to *possibly* register as a block-level 3034 // expression. Basically, if an assignment occurs both in a subexpression and 3035 // at the block-level, it is a block-level expression. 3036 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 3037 3038 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3039 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3040 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3041 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3042 3043 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3044 3045 // Iterate over the statements again on identify the Expr* and Stmt* at the 3046 // block-level that are block-level expressions. 3047 3048 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3049 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3050 if (!CS) 3051 continue; 3052 if (Expr* Exp = dyn_cast<Expr>(CS->getStmt())) { 3053 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3054 3055 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3056 // Assignment expressions that are not nested within another 3057 // expression are really "statements" whose value is never used by 3058 // another expression. 3059 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3060 continue; 3061 } else if (const StmtExpr* SE = dyn_cast<StmtExpr>(Exp)) { 3062 // Special handling for statement expressions. The last statement in 3063 // the statement expression is also a block-level expr. 3064 const CompoundStmt* C = SE->getSubStmt(); 3065 if (!C->body_empty()) { 3066 const Stmt *Last = C->body_back(); 3067 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3068 Last = LastEx->IgnoreParens(); 3069 unsigned x = M->size(); 3070 (*M)[Last] = x; 3071 } 3072 } 3073 3074 unsigned x = M->size(); 3075 (*M)[Exp] = x; 3076 } 3077 } 3078 3079 // Look at terminators. The condition is a block-level expression. 3080 3081 Stmt* S = (*I)->getTerminatorCondition(); 3082 3083 if (S && M->find(S) == M->end()) { 3084 unsigned x = M->size(); 3085 (*M)[S] = x; 3086 } 3087 } 3088 3089 return M; 3090} 3091 3092CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 3093 assert(S != NULL); 3094 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3095 3096 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3097 BlkExprMapTy::iterator I = M->find(S); 3098 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3099} 3100 3101unsigned CFG::getNumBlkExprs() { 3102 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3103 return M->size(); 3104 3105 // We assume callers interested in the number of BlkExprs will want 3106 // the map constructed if it doesn't already exist. 3107 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3108 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3109} 3110 3111//===----------------------------------------------------------------------===// 3112// Filtered walking of the CFG. 3113//===----------------------------------------------------------------------===// 3114 3115bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3116 const CFGBlock *From, const CFGBlock *To) { 3117 3118 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3119 // If the 'To' has no label or is labeled but the label isn't a 3120 // CaseStmt then filter this edge. 3121 if (const SwitchStmt *S = 3122 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3123 if (S->isAllEnumCasesCovered()) { 3124 const Stmt *L = To->getLabel(); 3125 if (!L || !isa<CaseStmt>(L)) 3126 return true; 3127 } 3128 } 3129 } 3130 3131 return false; 3132} 3133 3134//===----------------------------------------------------------------------===// 3135// Cleanup: CFG dstor. 3136//===----------------------------------------------------------------------===// 3137 3138CFG::~CFG() { 3139 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3140} 3141 3142//===----------------------------------------------------------------------===// 3143// CFG pretty printing 3144//===----------------------------------------------------------------------===// 3145 3146namespace { 3147 3148class StmtPrinterHelper : public PrinterHelper { 3149 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3150 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3151 StmtMapTy StmtMap; 3152 DeclMapTy DeclMap; 3153 signed currentBlock; 3154 unsigned currentStmt; 3155 const LangOptions &LangOpts; 3156public: 3157 3158 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3159 : currentBlock(0), currentStmt(0), LangOpts(LO) 3160 { 3161 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3162 unsigned j = 1; 3163 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3164 BI != BEnd; ++BI, ++j ) { 3165 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3166 const Stmt *stmt= SE->getStmt(); 3167 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3168 StmtMap[stmt] = P; 3169 3170 switch (stmt->getStmtClass()) { 3171 case Stmt::DeclStmtClass: 3172 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3173 break; 3174 case Stmt::IfStmtClass: { 3175 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3176 if (var) 3177 DeclMap[var] = P; 3178 break; 3179 } 3180 case Stmt::ForStmtClass: { 3181 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3182 if (var) 3183 DeclMap[var] = P; 3184 break; 3185 } 3186 case Stmt::WhileStmtClass: { 3187 const VarDecl *var = 3188 cast<WhileStmt>(stmt)->getConditionVariable(); 3189 if (var) 3190 DeclMap[var] = P; 3191 break; 3192 } 3193 case Stmt::SwitchStmtClass: { 3194 const VarDecl *var = 3195 cast<SwitchStmt>(stmt)->getConditionVariable(); 3196 if (var) 3197 DeclMap[var] = P; 3198 break; 3199 } 3200 case Stmt::CXXCatchStmtClass: { 3201 const VarDecl *var = 3202 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3203 if (var) 3204 DeclMap[var] = P; 3205 break; 3206 } 3207 default: 3208 break; 3209 } 3210 } 3211 } 3212 } 3213 } 3214 3215 3216 virtual ~StmtPrinterHelper() {} 3217 3218 const LangOptions &getLangOpts() const { return LangOpts; } 3219 void setBlockID(signed i) { currentBlock = i; } 3220 void setStmtID(unsigned i) { currentStmt = i; } 3221 3222 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 3223 StmtMapTy::iterator I = StmtMap.find(S); 3224 3225 if (I == StmtMap.end()) 3226 return false; 3227 3228 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3229 && I->second.second == currentStmt) { 3230 return false; 3231 } 3232 3233 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3234 return true; 3235 } 3236 3237 bool handleDecl(const Decl* D, llvm::raw_ostream& OS) { 3238 DeclMapTy::iterator I = DeclMap.find(D); 3239 3240 if (I == DeclMap.end()) 3241 return false; 3242 3243 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3244 && I->second.second == currentStmt) { 3245 return false; 3246 } 3247 3248 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3249 return true; 3250 } 3251}; 3252} // end anonymous namespace 3253 3254 3255namespace { 3256class CFGBlockTerminatorPrint 3257 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3258 3259 llvm::raw_ostream& OS; 3260 StmtPrinterHelper* Helper; 3261 PrintingPolicy Policy; 3262public: 3263 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 3264 const PrintingPolicy &Policy) 3265 : OS(os), Helper(helper), Policy(Policy) {} 3266 3267 void VisitIfStmt(IfStmt* I) { 3268 OS << "if "; 3269 I->getCond()->printPretty(OS,Helper,Policy); 3270 } 3271 3272 // Default case. 3273 void VisitStmt(Stmt* Terminator) { 3274 Terminator->printPretty(OS, Helper, Policy); 3275 } 3276 3277 void VisitForStmt(ForStmt* F) { 3278 OS << "for (" ; 3279 if (F->getInit()) 3280 OS << "..."; 3281 OS << "; "; 3282 if (Stmt* C = F->getCond()) 3283 C->printPretty(OS, Helper, Policy); 3284 OS << "; "; 3285 if (F->getInc()) 3286 OS << "..."; 3287 OS << ")"; 3288 } 3289 3290 void VisitWhileStmt(WhileStmt* W) { 3291 OS << "while " ; 3292 if (Stmt* C = W->getCond()) 3293 C->printPretty(OS, Helper, Policy); 3294 } 3295 3296 void VisitDoStmt(DoStmt* D) { 3297 OS << "do ... while "; 3298 if (Stmt* C = D->getCond()) 3299 C->printPretty(OS, Helper, Policy); 3300 } 3301 3302 void VisitSwitchStmt(SwitchStmt* Terminator) { 3303 OS << "switch "; 3304 Terminator->getCond()->printPretty(OS, Helper, Policy); 3305 } 3306 3307 void VisitCXXTryStmt(CXXTryStmt* CS) { 3308 OS << "try ..."; 3309 } 3310 3311 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3312 C->getCond()->printPretty(OS, Helper, Policy); 3313 OS << " ? ... : ..."; 3314 } 3315 3316 void VisitChooseExpr(ChooseExpr* C) { 3317 OS << "__builtin_choose_expr( "; 3318 C->getCond()->printPretty(OS, Helper, Policy); 3319 OS << " )"; 3320 } 3321 3322 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 3323 OS << "goto *"; 3324 I->getTarget()->printPretty(OS, Helper, Policy); 3325 } 3326 3327 void VisitBinaryOperator(BinaryOperator* B) { 3328 if (!B->isLogicalOp()) { 3329 VisitExpr(B); 3330 return; 3331 } 3332 3333 B->getLHS()->printPretty(OS, Helper, Policy); 3334 3335 switch (B->getOpcode()) { 3336 case BO_LOr: 3337 OS << " || ..."; 3338 return; 3339 case BO_LAnd: 3340 OS << " && ..."; 3341 return; 3342 default: 3343 assert(false && "Invalid logical operator."); 3344 } 3345 } 3346 3347 void VisitExpr(Expr* E) { 3348 E->printPretty(OS, Helper, Policy); 3349 } 3350}; 3351} // end anonymous namespace 3352 3353static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3354 const CFGElement &E) { 3355 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3356 Stmt *S = CS->getStmt(); 3357 3358 if (Helper) { 3359 3360 // special printing for statement-expressions. 3361 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3362 CompoundStmt* Sub = SE->getSubStmt(); 3363 3364 if (Sub->children()) { 3365 OS << "({ ... ; "; 3366 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3367 OS << " })\n"; 3368 return; 3369 } 3370 } 3371 // special printing for comma expressions. 3372 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3373 if (B->getOpcode() == BO_Comma) { 3374 OS << "... , "; 3375 Helper->handledStmt(B->getRHS(),OS); 3376 OS << '\n'; 3377 return; 3378 } 3379 } 3380 } 3381 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3382 3383 if (isa<CXXOperatorCallExpr>(S)) { 3384 OS << " (OperatorCall)"; 3385 } else if (isa<CXXBindTemporaryExpr>(S)) { 3386 OS << " (BindTemporary)"; 3387 } 3388 3389 // Expressions need a newline. 3390 if (isa<Expr>(S)) 3391 OS << '\n'; 3392 3393 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3394 const CXXCtorInitializer *I = IE->getInitializer(); 3395 if (I->isBaseInitializer()) 3396 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3397 else OS << I->getAnyMember()->getName(); 3398 3399 OS << "("; 3400 if (Expr* IE = I->getInit()) 3401 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3402 OS << ")"; 3403 3404 if (I->isBaseInitializer()) 3405 OS << " (Base initializer)\n"; 3406 else OS << " (Member initializer)\n"; 3407 3408 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3409 const VarDecl* VD = DE->getVarDecl(); 3410 Helper->handleDecl(VD, OS); 3411 3412 const Type* T = VD->getType().getTypePtr(); 3413 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3414 T = RT->getPointeeType().getTypePtr(); 3415 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3416 T = ET; 3417 3418 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3419 OS << " (Implicit destructor)\n"; 3420 3421 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3422 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3423 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3424 OS << " (Base object destructor)\n"; 3425 3426 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3427 const FieldDecl *FD = ME->getFieldDecl(); 3428 3429 const Type *T = FD->getType().getTypePtr(); 3430 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3431 T = ET; 3432 3433 OS << "this->" << FD->getName(); 3434 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3435 OS << " (Member object destructor)\n"; 3436 3437 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3438 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3439 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3440 OS << " (Temporary object destructor)\n"; 3441 } 3442} 3443 3444static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3445 const CFGBlock& B, 3446 StmtPrinterHelper* Helper, bool print_edges) { 3447 3448 if (Helper) Helper->setBlockID(B.getBlockID()); 3449 3450 // Print the header. 3451 OS << "\n [ B" << B.getBlockID(); 3452 3453 if (&B == &cfg->getEntry()) 3454 OS << " (ENTRY) ]\n"; 3455 else if (&B == &cfg->getExit()) 3456 OS << " (EXIT) ]\n"; 3457 else if (&B == cfg->getIndirectGotoBlock()) 3458 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3459 else 3460 OS << " ]\n"; 3461 3462 // Print the label of this block. 3463 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3464 3465 if (print_edges) 3466 OS << " "; 3467 3468 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3469 OS << L->getName(); 3470 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3471 OS << "case "; 3472 C->getLHS()->printPretty(OS, Helper, 3473 PrintingPolicy(Helper->getLangOpts())); 3474 if (C->getRHS()) { 3475 OS << " ... "; 3476 C->getRHS()->printPretty(OS, Helper, 3477 PrintingPolicy(Helper->getLangOpts())); 3478 } 3479 } else if (isa<DefaultStmt>(Label)) 3480 OS << "default"; 3481 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3482 OS << "catch ("; 3483 if (CS->getExceptionDecl()) 3484 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3485 0); 3486 else 3487 OS << "..."; 3488 OS << ")"; 3489 3490 } else 3491 assert(false && "Invalid label statement in CFGBlock."); 3492 3493 OS << ":\n"; 3494 } 3495 3496 // Iterate through the statements in the block and print them. 3497 unsigned j = 1; 3498 3499 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3500 I != E ; ++I, ++j ) { 3501 3502 // Print the statement # in the basic block and the statement itself. 3503 if (print_edges) 3504 OS << " "; 3505 3506 OS << llvm::format("%3d", j) << ": "; 3507 3508 if (Helper) 3509 Helper->setStmtID(j); 3510 3511 print_elem(OS,Helper,*I); 3512 } 3513 3514 // Print the terminator of this block. 3515 if (B.getTerminator()) { 3516 if (print_edges) 3517 OS << " "; 3518 3519 OS << " T: "; 3520 3521 if (Helper) Helper->setBlockID(-1); 3522 3523 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3524 PrintingPolicy(Helper->getLangOpts())); 3525 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3526 OS << '\n'; 3527 } 3528 3529 if (print_edges) { 3530 // Print the predecessors of this block. 3531 OS << " Predecessors (" << B.pred_size() << "):"; 3532 unsigned i = 0; 3533 3534 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3535 I != E; ++I, ++i) { 3536 3537 if (i == 8 || (i-8) == 0) 3538 OS << "\n "; 3539 3540 OS << " B" << (*I)->getBlockID(); 3541 } 3542 3543 OS << '\n'; 3544 3545 // Print the successors of this block. 3546 OS << " Successors (" << B.succ_size() << "):"; 3547 i = 0; 3548 3549 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3550 I != E; ++I, ++i) { 3551 3552 if (i == 8 || (i-8) % 10 == 0) 3553 OS << "\n "; 3554 3555 if (*I) 3556 OS << " B" << (*I)->getBlockID(); 3557 else 3558 OS << " NULL"; 3559 } 3560 3561 OS << '\n'; 3562 } 3563} 3564 3565 3566/// dump - A simple pretty printer of a CFG that outputs to stderr. 3567void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3568 3569/// print - A simple pretty printer of a CFG that outputs to an ostream. 3570void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3571 StmtPrinterHelper Helper(this, LO); 3572 3573 // Print the entry block. 3574 print_block(OS, this, getEntry(), &Helper, true); 3575 3576 // Iterate through the CFGBlocks and print them one by one. 3577 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3578 // Skip the entry block, because we already printed it. 3579 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3580 continue; 3581 3582 print_block(OS, this, **I, &Helper, true); 3583 } 3584 3585 // Print the exit block. 3586 print_block(OS, this, getExit(), &Helper, true); 3587 OS.flush(); 3588} 3589 3590/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3591void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3592 print(llvm::errs(), cfg, LO); 3593} 3594 3595/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3596/// Generally this will only be called from CFG::print. 3597void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3598 const LangOptions &LO) const { 3599 StmtPrinterHelper Helper(cfg, LO); 3600 print_block(OS, cfg, *this, &Helper, true); 3601} 3602 3603/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3604void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3605 const LangOptions &LO) const { 3606 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3607 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3608} 3609 3610Stmt* CFGBlock::getTerminatorCondition() { 3611 Stmt *Terminator = this->Terminator; 3612 if (!Terminator) 3613 return NULL; 3614 3615 Expr* E = NULL; 3616 3617 switch (Terminator->getStmtClass()) { 3618 default: 3619 break; 3620 3621 case Stmt::ForStmtClass: 3622 E = cast<ForStmt>(Terminator)->getCond(); 3623 break; 3624 3625 case Stmt::WhileStmtClass: 3626 E = cast<WhileStmt>(Terminator)->getCond(); 3627 break; 3628 3629 case Stmt::DoStmtClass: 3630 E = cast<DoStmt>(Terminator)->getCond(); 3631 break; 3632 3633 case Stmt::IfStmtClass: 3634 E = cast<IfStmt>(Terminator)->getCond(); 3635 break; 3636 3637 case Stmt::ChooseExprClass: 3638 E = cast<ChooseExpr>(Terminator)->getCond(); 3639 break; 3640 3641 case Stmt::IndirectGotoStmtClass: 3642 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3643 break; 3644 3645 case Stmt::SwitchStmtClass: 3646 E = cast<SwitchStmt>(Terminator)->getCond(); 3647 break; 3648 3649 case Stmt::BinaryConditionalOperatorClass: 3650 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3651 break; 3652 3653 case Stmt::ConditionalOperatorClass: 3654 E = cast<ConditionalOperator>(Terminator)->getCond(); 3655 break; 3656 3657 case Stmt::BinaryOperatorClass: // '&&' and '||' 3658 E = cast<BinaryOperator>(Terminator)->getLHS(); 3659 break; 3660 3661 case Stmt::ObjCForCollectionStmtClass: 3662 return Terminator; 3663 } 3664 3665 return E ? E->IgnoreParens() : NULL; 3666} 3667 3668//===----------------------------------------------------------------------===// 3669// CFG Graphviz Visualization 3670//===----------------------------------------------------------------------===// 3671 3672 3673#ifndef NDEBUG 3674static StmtPrinterHelper* GraphHelper; 3675#endif 3676 3677void CFG::viewCFG(const LangOptions &LO) const { 3678#ifndef NDEBUG 3679 StmtPrinterHelper H(this, LO); 3680 GraphHelper = &H; 3681 llvm::ViewGraph(this,"CFG"); 3682 GraphHelper = NULL; 3683#endif 3684} 3685 3686namespace llvm { 3687template<> 3688struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3689 3690 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3691 3692 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3693 3694#ifndef NDEBUG 3695 std::string OutSStr; 3696 llvm::raw_string_ostream Out(OutSStr); 3697 print_block(Out,Graph, *Node, GraphHelper, false); 3698 std::string& OutStr = Out.str(); 3699 3700 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3701 3702 // Process string output to make it nicer... 3703 for (unsigned i = 0; i != OutStr.length(); ++i) 3704 if (OutStr[i] == '\n') { // Left justify 3705 OutStr[i] = '\\'; 3706 OutStr.insert(OutStr.begin()+i+1, 'l'); 3707 } 3708 3709 return OutStr; 3710#else 3711 return ""; 3712#endif 3713 } 3714}; 3715} // end namespace llvm 3716