CFG.cpp revision 7acf4bf00ecc31652177b3ac1d3f523346581d71
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 *VisitPseudoObjectExpr(PseudoObjectExpr *E); 348 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 349 AddStmtChoice asc); 350 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 351 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 352 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 353 CFGBlock *VisitWhileStmt(WhileStmt *W); 354 355 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 356 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 357 CFGBlock *VisitChildren(Stmt *S); 358 359 // Visitors to walk an AST and generate destructors of temporaries in 360 // full expression. 361 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 362 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 363 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 364 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 365 bool BindToTemporary); 366 CFGBlock * 367 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 368 bool BindToTemporary); 369 370 // NYS == Not Yet Supported 371 CFGBlock *NYS() { 372 badCFG = true; 373 return Block; 374 } 375 376 void autoCreateBlock() { if (!Block) Block = createBlock(); } 377 CFGBlock *createBlock(bool add_successor = true); 378 CFGBlock *createNoReturnBlock(); 379 380 CFGBlock *addStmt(Stmt *S) { 381 return Visit(S, AddStmtChoice::AlwaysAdd); 382 } 383 CFGBlock *addInitializer(CXXCtorInitializer *I); 384 void addAutomaticObjDtors(LocalScope::const_iterator B, 385 LocalScope::const_iterator E, Stmt *S); 386 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 387 388 // Local scopes creation. 389 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 390 391 void addLocalScopeForStmt(Stmt *S); 392 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 393 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 394 395 void addLocalScopeAndDtors(Stmt *S); 396 397 // Interface to CFGBlock - adding CFGElements. 398 void appendStmt(CFGBlock *B, const Stmt *S) { 399 if (alwaysAdd(S) && cachedEntry) 400 cachedEntry->second = B; 401 402 // All block-level expressions should have already been IgnoreParens()ed. 403 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 404 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 405 } 406 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 407 B->appendInitializer(I, cfg->getBumpVectorContext()); 408 } 409 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 410 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 411 } 412 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 413 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 414 } 415 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 416 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 417 } 418 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 419 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 420 } 421 422 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 423 LocalScope::const_iterator B, LocalScope::const_iterator E); 424 425 void addSuccessor(CFGBlock *B, CFGBlock *S) { 426 B->addSuccessor(S, cfg->getBumpVectorContext()); 427 } 428 429 /// Try and evaluate an expression to an integer constant. 430 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 431 if (!BuildOpts.PruneTriviallyFalseEdges) 432 return false; 433 return !S->isTypeDependent() && 434 !S->isValueDependent() && 435 S->EvaluateAsRValue(outResult, *Context); 436 } 437 438 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 439 /// if we can evaluate to a known value, otherwise return -1. 440 TryResult tryEvaluateBool(Expr *S) { 441 bool Result; 442 if (!BuildOpts.PruneTriviallyFalseEdges || 443 S->isTypeDependent() || S->isValueDependent() || 444 !S->EvaluateAsBooleanCondition(Result, *Context)) 445 return TryResult(); 446 return Result; 447 } 448 449}; 450 451inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 452 const Stmt *stmt) const { 453 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 454} 455 456bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 457 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 458 459 if (!BuildOpts.forcedBlkExprs) 460 return shouldAdd; 461 462 if (lastLookup == stmt) { 463 if (cachedEntry) { 464 assert(cachedEntry->first == stmt); 465 return true; 466 } 467 return shouldAdd; 468 } 469 470 lastLookup = stmt; 471 472 // Perform the lookup! 473 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 474 475 if (!fb) { 476 // No need to update 'cachedEntry', since it will always be null. 477 assert(cachedEntry == 0); 478 return shouldAdd; 479 } 480 481 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 482 if (itr == fb->end()) { 483 cachedEntry = 0; 484 return shouldAdd; 485 } 486 487 cachedEntry = &*itr; 488 return true; 489} 490 491// FIXME: Add support for dependent-sized array types in C++? 492// Does it even make sense to build a CFG for an uninstantiated template? 493static const VariableArrayType *FindVA(const Type *t) { 494 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 495 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 496 if (vat->getSizeExpr()) 497 return vat; 498 499 t = vt->getElementType().getTypePtr(); 500 } 501 502 return 0; 503} 504 505/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 506/// arbitrary statement. Examples include a single expression or a function 507/// body (compound statement). The ownership of the returned CFG is 508/// transferred to the caller. If CFG construction fails, this method returns 509/// NULL. 510CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 511 assert(cfg.get()); 512 if (!Statement) 513 return NULL; 514 515 // Create an empty block that will serve as the exit block for the CFG. Since 516 // this is the first block added to the CFG, it will be implicitly registered 517 // as the exit block. 518 Succ = createBlock(); 519 assert(Succ == &cfg->getExit()); 520 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 521 522 if (BuildOpts.AddImplicitDtors) 523 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 524 addImplicitDtorsForDestructor(DD); 525 526 // Visit the statements and create the CFG. 527 CFGBlock *B = addStmt(Statement); 528 529 if (badCFG) 530 return NULL; 531 532 // For C++ constructor add initializers to CFG. 533 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 534 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 535 E = CD->init_rend(); I != E; ++I) { 536 B = addInitializer(*I); 537 if (badCFG) 538 return NULL; 539 } 540 } 541 542 if (B) 543 Succ = B; 544 545 // Backpatch the gotos whose label -> block mappings we didn't know when we 546 // encountered them. 547 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 548 E = BackpatchBlocks.end(); I != E; ++I ) { 549 550 CFGBlock *B = I->block; 551 GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 552 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 553 554 // If there is no target for the goto, then we are looking at an 555 // incomplete AST. Handle this by not registering a successor. 556 if (LI == LabelMap.end()) continue; 557 558 JumpTarget JT = LI->second; 559 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 560 JT.scopePosition); 561 addSuccessor(B, JT.block); 562 } 563 564 // Add successors to the Indirect Goto Dispatch block (if we have one). 565 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 566 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 567 E = AddressTakenLabels.end(); I != E; ++I ) { 568 569 // Lookup the target block. 570 LabelMapTy::iterator LI = LabelMap.find(*I); 571 572 // If there is no target block that contains label, then we are looking 573 // at an incomplete AST. Handle this by not registering a successor. 574 if (LI == LabelMap.end()) continue; 575 576 addSuccessor(B, LI->second.block); 577 } 578 579 // Create an empty entry block that has no predecessors. 580 cfg->setEntry(createBlock()); 581 582 return cfg.take(); 583} 584 585/// createBlock - Used to lazily create blocks that are connected 586/// to the current (global) succcessor. 587CFGBlock *CFGBuilder::createBlock(bool add_successor) { 588 CFGBlock *B = cfg->createBlock(); 589 if (add_successor && Succ) 590 addSuccessor(B, Succ); 591 return B; 592} 593 594/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the 595/// CFG. It is *not* connected to the current (global) successor, and instead 596/// directly tied to the exit block in order to be reachable. 597CFGBlock *CFGBuilder::createNoReturnBlock() { 598 CFGBlock *B = createBlock(false); 599 B->setHasNoReturnElement(); 600 addSuccessor(B, &cfg->getExit()); 601 return B; 602} 603 604/// addInitializer - Add C++ base or member initializer element to CFG. 605CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 606 if (!BuildOpts.AddInitializers) 607 return Block; 608 609 bool IsReference = false; 610 bool HasTemporaries = false; 611 612 // Destructors of temporaries in initialization expression should be called 613 // after initialization finishes. 614 Expr *Init = I->getInit(); 615 if (Init) { 616 if (FieldDecl *FD = I->getAnyMember()) 617 IsReference = FD->getType()->isReferenceType(); 618 HasTemporaries = isa<ExprWithCleanups>(Init); 619 620 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 621 // Generate destructors for temporaries in initialization expression. 622 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 623 IsReference); 624 } 625 } 626 627 autoCreateBlock(); 628 appendInitializer(Block, I); 629 630 if (Init) { 631 if (HasTemporaries) { 632 // For expression with temporaries go directly to subexpression to omit 633 // generating destructors for the second time. 634 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 635 } 636 return Visit(Init); 637 } 638 639 return Block; 640} 641 642/// addAutomaticObjDtors - Add to current block automatic objects destructors 643/// for objects in range of local scope positions. Use S as trigger statement 644/// for destructors. 645void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 646 LocalScope::const_iterator E, Stmt *S) { 647 if (!BuildOpts.AddImplicitDtors) 648 return; 649 650 if (B == E) 651 return; 652 653 CFGBlock::iterator InsertPos; 654 655 // We need to append the destructors in reverse order, but any one of them 656 // may be a no-return destructor which changes the CFG. As a result, buffer 657 // this sequence up and replay them in reverse order when appending onto the 658 // CFGBlock(s). 659 SmallVector<VarDecl*, 10> Decls; 660 Decls.reserve(B.distance(E)); 661 for (LocalScope::const_iterator I = B; I != E; ++I) 662 Decls.push_back(*I); 663 664 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 665 E = Decls.rend(); 666 I != E; ++I) { 667 // If this destructor is marked as a no-return destructor, we need to 668 // create a new block for the destructor which does not have as a successor 669 // anything built thus far: control won't flow out of this block. 670 QualType Ty = (*I)->getType().getNonReferenceType(); 671 if (const ArrayType *AT = Context->getAsArrayType(Ty)) 672 Ty = AT->getElementType(); 673 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 674 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 675 Block = createNoReturnBlock(); 676 else 677 autoCreateBlock(); 678 679 appendAutomaticObjDtor(Block, *I, S); 680 } 681} 682 683/// addImplicitDtorsForDestructor - Add implicit destructors generated for 684/// base and member objects in destructor. 685void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 686 assert (BuildOpts.AddImplicitDtors 687 && "Can be called only when dtors should be added"); 688 const CXXRecordDecl *RD = DD->getParent(); 689 690 // At the end destroy virtual base objects. 691 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 692 VE = RD->vbases_end(); VI != VE; ++VI) { 693 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 694 if (!CD->hasTrivialDestructor()) { 695 autoCreateBlock(); 696 appendBaseDtor(Block, VI); 697 } 698 } 699 700 // Before virtual bases destroy direct base objects. 701 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 702 BE = RD->bases_end(); BI != BE; ++BI) { 703 if (!BI->isVirtual()) { 704 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 705 if (!CD->hasTrivialDestructor()) { 706 autoCreateBlock(); 707 appendBaseDtor(Block, BI); 708 } 709 } 710 } 711 712 // First destroy member objects. 713 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 714 FE = RD->field_end(); FI != FE; ++FI) { 715 // Check for constant size array. Set type to array element type. 716 QualType QT = FI->getType(); 717 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 718 if (AT->getSize() == 0) 719 continue; 720 QT = AT->getElementType(); 721 } 722 723 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 724 if (!CD->hasTrivialDestructor()) { 725 autoCreateBlock(); 726 appendMemberDtor(Block, *FI); 727 } 728 } 729} 730 731/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 732/// way return valid LocalScope object. 733LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 734 if (!Scope) { 735 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 736 Scope = alloc.Allocate<LocalScope>(); 737 BumpVectorContext ctx(alloc); 738 new (Scope) LocalScope(ctx, ScopePos); 739 } 740 return Scope; 741} 742 743/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 744/// that should create implicit scope (e.g. if/else substatements). 745void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 746 if (!BuildOpts.AddImplicitDtors) 747 return; 748 749 LocalScope *Scope = 0; 750 751 // For compound statement we will be creating explicit scope. 752 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 753 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 754 ; BI != BE; ++BI) { 755 Stmt *SI = (*BI)->stripLabelLikeStatements(); 756 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 757 Scope = addLocalScopeForDeclStmt(DS, Scope); 758 } 759 return; 760 } 761 762 // For any other statement scope will be implicit and as such will be 763 // interesting only for DeclStmt. 764 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 765 addLocalScopeForDeclStmt(DS); 766} 767 768/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 769/// reuse Scope if not NULL. 770LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 771 LocalScope* Scope) { 772 if (!BuildOpts.AddImplicitDtors) 773 return Scope; 774 775 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 776 ; DI != DE; ++DI) { 777 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 778 Scope = addLocalScopeForVarDecl(VD, Scope); 779 } 780 return Scope; 781} 782 783/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 784/// create add scope for automatic objects and temporary objects bound to 785/// const reference. Will reuse Scope if not NULL. 786LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 787 LocalScope* Scope) { 788 if (!BuildOpts.AddImplicitDtors) 789 return Scope; 790 791 // Check if variable is local. 792 switch (VD->getStorageClass()) { 793 case SC_None: 794 case SC_Auto: 795 case SC_Register: 796 break; 797 default: return Scope; 798 } 799 800 // Check for const references bound to temporary. Set type to pointee. 801 QualType QT = VD->getType(); 802 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 803 QT = RT->getPointeeType(); 804 if (!QT.isConstQualified()) 805 return Scope; 806 if (!VD->extendsLifetimeOfTemporary()) 807 return Scope; 808 } 809 810 // Check for constant size array. Set type to array element type. 811 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 812 if (AT->getSize() == 0) 813 return Scope; 814 QT = AT->getElementType(); 815 } 816 817 // Check if type is a C++ class with non-trivial destructor. 818 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 819 if (!CD->hasTrivialDestructor()) { 820 // Add the variable to scope 821 Scope = createOrReuseLocalScope(Scope); 822 Scope->addVar(VD); 823 ScopePos = Scope->begin(); 824 } 825 return Scope; 826} 827 828/// addLocalScopeAndDtors - For given statement add local scope for it and 829/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 830void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 831 if (!BuildOpts.AddImplicitDtors) 832 return; 833 834 LocalScope::const_iterator scopeBeginPos = ScopePos; 835 addLocalScopeForStmt(S); 836 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 837} 838 839/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 840/// variables with automatic storage duration to CFGBlock's elements vector. 841/// Elements will be prepended to physical beginning of the vector which 842/// happens to be logical end. Use blocks terminator as statement that specifies 843/// destructors call site. 844/// FIXME: This mechanism for adding automatic destructors doesn't handle 845/// no-return destructors properly. 846void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 847 LocalScope::const_iterator B, LocalScope::const_iterator E) { 848 BumpVectorContext &C = cfg->getBumpVectorContext(); 849 CFGBlock::iterator InsertPos 850 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 851 for (LocalScope::const_iterator I = B; I != E; ++I) 852 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 853 Blk->getTerminator()); 854} 855 856/// Visit - Walk the subtree of a statement and add extra 857/// blocks for ternary operators, &&, and ||. We also process "," and 858/// DeclStmts (which may contain nested control-flow). 859CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 860 if (!S) { 861 badCFG = true; 862 return 0; 863 } 864 865 if (Expr *E = dyn_cast<Expr>(S)) 866 S = E->IgnoreParens(); 867 868 switch (S->getStmtClass()) { 869 default: 870 return VisitStmt(S, asc); 871 872 case Stmt::AddrLabelExprClass: 873 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 874 875 case Stmt::BinaryConditionalOperatorClass: 876 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 877 878 case Stmt::BinaryOperatorClass: 879 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 880 881 case Stmt::BlockExprClass: 882 return VisitBlockExpr(cast<BlockExpr>(S), asc); 883 884 case Stmt::BreakStmtClass: 885 return VisitBreakStmt(cast<BreakStmt>(S)); 886 887 case Stmt::CallExprClass: 888 case Stmt::CXXOperatorCallExprClass: 889 case Stmt::CXXMemberCallExprClass: 890 return VisitCallExpr(cast<CallExpr>(S), asc); 891 892 case Stmt::CaseStmtClass: 893 return VisitCaseStmt(cast<CaseStmt>(S)); 894 895 case Stmt::ChooseExprClass: 896 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 897 898 case Stmt::CompoundStmtClass: 899 return VisitCompoundStmt(cast<CompoundStmt>(S)); 900 901 case Stmt::ConditionalOperatorClass: 902 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 903 904 case Stmt::ContinueStmtClass: 905 return VisitContinueStmt(cast<ContinueStmt>(S)); 906 907 case Stmt::CXXCatchStmtClass: 908 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 909 910 case Stmt::ExprWithCleanupsClass: 911 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 912 913 case Stmt::CXXBindTemporaryExprClass: 914 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 915 916 case Stmt::CXXConstructExprClass: 917 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 918 919 case Stmt::CXXFunctionalCastExprClass: 920 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 921 922 case Stmt::CXXTemporaryObjectExprClass: 923 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 924 925 case Stmt::CXXThrowExprClass: 926 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 927 928 case Stmt::CXXTryStmtClass: 929 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 930 931 case Stmt::CXXForRangeStmtClass: 932 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 933 934 case Stmt::DeclStmtClass: 935 return VisitDeclStmt(cast<DeclStmt>(S)); 936 937 case Stmt::DefaultStmtClass: 938 return VisitDefaultStmt(cast<DefaultStmt>(S)); 939 940 case Stmt::DoStmtClass: 941 return VisitDoStmt(cast<DoStmt>(S)); 942 943 case Stmt::ForStmtClass: 944 return VisitForStmt(cast<ForStmt>(S)); 945 946 case Stmt::GotoStmtClass: 947 return VisitGotoStmt(cast<GotoStmt>(S)); 948 949 case Stmt::IfStmtClass: 950 return VisitIfStmt(cast<IfStmt>(S)); 951 952 case Stmt::ImplicitCastExprClass: 953 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 954 955 case Stmt::IndirectGotoStmtClass: 956 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 957 958 case Stmt::LabelStmtClass: 959 return VisitLabelStmt(cast<LabelStmt>(S)); 960 961 case Stmt::MemberExprClass: 962 return VisitMemberExpr(cast<MemberExpr>(S), asc); 963 964 case Stmt::NullStmtClass: 965 return Block; 966 967 case Stmt::ObjCAtCatchStmtClass: 968 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 969 970 case Stmt::ObjCAtSynchronizedStmtClass: 971 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 972 973 case Stmt::ObjCAtThrowStmtClass: 974 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 975 976 case Stmt::ObjCAtTryStmtClass: 977 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 978 979 case Stmt::ObjCForCollectionStmtClass: 980 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 981 982 case Stmt::OpaqueValueExprClass: 983 return Block; 984 985 case Stmt::PseudoObjectExprClass: 986 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S)); 987 988 case Stmt::ReturnStmtClass: 989 return VisitReturnStmt(cast<ReturnStmt>(S)); 990 991 case Stmt::UnaryExprOrTypeTraitExprClass: 992 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 993 asc); 994 995 case Stmt::StmtExprClass: 996 return VisitStmtExpr(cast<StmtExpr>(S), asc); 997 998 case Stmt::SwitchStmtClass: 999 return VisitSwitchStmt(cast<SwitchStmt>(S)); 1000 1001 case Stmt::UnaryOperatorClass: 1002 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 1003 1004 case Stmt::WhileStmtClass: 1005 return VisitWhileStmt(cast<WhileStmt>(S)); 1006 } 1007} 1008 1009CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1010 if (asc.alwaysAdd(*this, S)) { 1011 autoCreateBlock(); 1012 appendStmt(Block, S); 1013 } 1014 1015 return VisitChildren(S); 1016} 1017 1018/// VisitChildren - Visit the children of a Stmt. 1019CFGBlock *CFGBuilder::VisitChildren(Stmt *Terminator) { 1020 CFGBlock *lastBlock = Block; 1021 for (Stmt::child_range I = Terminator->children(); I; ++I) 1022 if (Stmt *child = *I) 1023 if (CFGBlock *b = Visit(child)) 1024 lastBlock = b; 1025 1026 return lastBlock; 1027} 1028 1029CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1030 AddStmtChoice asc) { 1031 AddressTakenLabels.insert(A->getLabel()); 1032 1033 if (asc.alwaysAdd(*this, A)) { 1034 autoCreateBlock(); 1035 appendStmt(Block, A); 1036 } 1037 1038 return Block; 1039} 1040 1041CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1042 AddStmtChoice asc) { 1043 if (asc.alwaysAdd(*this, U)) { 1044 autoCreateBlock(); 1045 appendStmt(Block, U); 1046 } 1047 1048 return Visit(U->getSubExpr(), AddStmtChoice()); 1049} 1050 1051CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1052 AddStmtChoice asc) { 1053 if (B->isLogicalOp()) { // && or || 1054 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1055 appendStmt(ConfluenceBlock, B); 1056 1057 if (badCFG) 1058 return 0; 1059 1060 // create the block evaluating the LHS 1061 CFGBlock *LHSBlock = createBlock(false); 1062 LHSBlock->setTerminator(B); 1063 1064 // create the block evaluating the RHS 1065 Succ = ConfluenceBlock; 1066 Block = NULL; 1067 CFGBlock *RHSBlock = addStmt(B->getRHS()); 1068 1069 if (RHSBlock) { 1070 if (badCFG) 1071 return 0; 1072 } else { 1073 // Create an empty block for cases where the RHS doesn't require 1074 // any explicit statements in the CFG. 1075 RHSBlock = createBlock(); 1076 } 1077 1078 // See if this is a known constant. 1079 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1080 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1081 KnownVal.negate(); 1082 1083 // Now link the LHSBlock with RHSBlock. 1084 if (B->getOpcode() == BO_LOr) { 1085 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1086 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1087 } else { 1088 assert(B->getOpcode() == BO_LAnd); 1089 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1090 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1091 } 1092 1093 // Generate the blocks for evaluating the LHS. 1094 Block = LHSBlock; 1095 return addStmt(B->getLHS()); 1096 } 1097 1098 if (B->getOpcode() == BO_Comma) { // , 1099 autoCreateBlock(); 1100 appendStmt(Block, B); 1101 addStmt(B->getRHS()); 1102 return addStmt(B->getLHS()); 1103 } 1104 1105 if (B->isAssignmentOp()) { 1106 if (asc.alwaysAdd(*this, B)) { 1107 autoCreateBlock(); 1108 appendStmt(Block, B); 1109 } 1110 Visit(B->getLHS()); 1111 return Visit(B->getRHS()); 1112 } 1113 1114 if (asc.alwaysAdd(*this, B)) { 1115 autoCreateBlock(); 1116 appendStmt(Block, B); 1117 } 1118 1119 CFGBlock *RBlock = Visit(B->getRHS()); 1120 CFGBlock *LBlock = Visit(B->getLHS()); 1121 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1122 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1123 // return RBlock. Otherwise we'll incorrectly return NULL. 1124 return (LBlock ? LBlock : RBlock); 1125} 1126 1127CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1128 if (asc.alwaysAdd(*this, E)) { 1129 autoCreateBlock(); 1130 appendStmt(Block, E); 1131 } 1132 return Block; 1133} 1134 1135CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1136 // "break" is a control-flow statement. Thus we stop processing the current 1137 // block. 1138 if (badCFG) 1139 return 0; 1140 1141 // Now create a new block that ends with the break statement. 1142 Block = createBlock(false); 1143 Block->setTerminator(B); 1144 1145 // If there is no target for the break, then we are looking at an incomplete 1146 // AST. This means that the CFG cannot be constructed. 1147 if (BreakJumpTarget.block) { 1148 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1149 addSuccessor(Block, BreakJumpTarget.block); 1150 } else 1151 badCFG = true; 1152 1153 1154 return Block; 1155} 1156 1157static bool CanThrow(Expr *E, ASTContext &Ctx) { 1158 QualType Ty = E->getType(); 1159 if (Ty->isFunctionPointerType()) 1160 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1161 else if (Ty->isBlockPointerType()) 1162 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1163 1164 const FunctionType *FT = Ty->getAs<FunctionType>(); 1165 if (FT) { 1166 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1167 if (Proto->isNothrow(Ctx)) 1168 return false; 1169 } 1170 return true; 1171} 1172 1173CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1174 // Compute the callee type. 1175 QualType calleeType = C->getCallee()->getType(); 1176 if (calleeType == Context->BoundMemberTy) { 1177 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1178 1179 // We should only get a null bound type if processing a dependent 1180 // CFG. Recover by assuming nothing. 1181 if (!boundType.isNull()) calleeType = boundType; 1182 } 1183 1184 // If this is a call to a no-return function, this stops the block here. 1185 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1186 1187 bool AddEHEdge = false; 1188 1189 // Languages without exceptions are assumed to not throw. 1190 if (Context->getLangOptions().Exceptions) { 1191 if (BuildOpts.AddEHEdges) 1192 AddEHEdge = true; 1193 } 1194 1195 if (FunctionDecl *FD = C->getDirectCallee()) { 1196 if (FD->hasAttr<NoReturnAttr>()) 1197 NoReturn = true; 1198 if (FD->hasAttr<NoThrowAttr>()) 1199 AddEHEdge = false; 1200 } 1201 1202 if (!CanThrow(C->getCallee(), *Context)) 1203 AddEHEdge = false; 1204 1205 if (!NoReturn && !AddEHEdge) 1206 return VisitStmt(C, asc.withAlwaysAdd(true)); 1207 1208 if (Block) { 1209 Succ = Block; 1210 if (badCFG) 1211 return 0; 1212 } 1213 1214 if (NoReturn) 1215 Block = createNoReturnBlock(); 1216 else 1217 Block = createBlock(); 1218 1219 appendStmt(Block, C); 1220 1221 if (AddEHEdge) { 1222 // Add exceptional edges. 1223 if (TryTerminatedBlock) 1224 addSuccessor(Block, TryTerminatedBlock); 1225 else 1226 addSuccessor(Block, &cfg->getExit()); 1227 } 1228 1229 return VisitChildren(C); 1230} 1231 1232CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1233 AddStmtChoice asc) { 1234 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1235 appendStmt(ConfluenceBlock, C); 1236 if (badCFG) 1237 return 0; 1238 1239 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1240 Succ = ConfluenceBlock; 1241 Block = NULL; 1242 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1243 if (badCFG) 1244 return 0; 1245 1246 Succ = ConfluenceBlock; 1247 Block = NULL; 1248 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1249 if (badCFG) 1250 return 0; 1251 1252 Block = createBlock(false); 1253 // See if this is a known constant. 1254 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1255 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1256 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1257 Block->setTerminator(C); 1258 return addStmt(C->getCond()); 1259} 1260 1261 1262CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1263 addLocalScopeAndDtors(C); 1264 CFGBlock *LastBlock = Block; 1265 1266 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1267 I != E; ++I ) { 1268 // If we hit a segment of code just containing ';' (NullStmts), we can 1269 // get a null block back. In such cases, just use the LastBlock 1270 if (CFGBlock *newBlock = addStmt(*I)) 1271 LastBlock = newBlock; 1272 1273 if (badCFG) 1274 return NULL; 1275 } 1276 1277 return LastBlock; 1278} 1279 1280CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1281 AddStmtChoice asc) { 1282 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1283 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1284 1285 // Create the confluence block that will "merge" the results of the ternary 1286 // expression. 1287 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1288 appendStmt(ConfluenceBlock, C); 1289 if (badCFG) 1290 return 0; 1291 1292 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1293 1294 // Create a block for the LHS expression if there is an LHS expression. A 1295 // GCC extension allows LHS to be NULL, causing the condition to be the 1296 // value that is returned instead. 1297 // e.g: x ?: y is shorthand for: x ? x : y; 1298 Succ = ConfluenceBlock; 1299 Block = NULL; 1300 CFGBlock *LHSBlock = 0; 1301 const Expr *trueExpr = C->getTrueExpr(); 1302 if (trueExpr != opaqueValue) { 1303 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1304 if (badCFG) 1305 return 0; 1306 Block = NULL; 1307 } 1308 else 1309 LHSBlock = ConfluenceBlock; 1310 1311 // Create the block for the RHS expression. 1312 Succ = ConfluenceBlock; 1313 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1314 if (badCFG) 1315 return 0; 1316 1317 // Create the block that will contain the condition. 1318 Block = createBlock(false); 1319 1320 // See if this is a known constant. 1321 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1322 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1323 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1324 Block->setTerminator(C); 1325 Expr *condExpr = C->getCond(); 1326 1327 if (opaqueValue) { 1328 // Run the condition expression if it's not trivially expressed in 1329 // terms of the opaque value (or if there is no opaque value). 1330 if (condExpr != opaqueValue) 1331 addStmt(condExpr); 1332 1333 // Before that, run the common subexpression if there was one. 1334 // At least one of this or the above will be run. 1335 return addStmt(BCO->getCommon()); 1336 } 1337 1338 return addStmt(condExpr); 1339} 1340 1341CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1342 // Check if the Decl is for an __label__. If so, elide it from the 1343 // CFG entirely. 1344 if (isa<LabelDecl>(*DS->decl_begin())) 1345 return Block; 1346 1347 // This case also handles static_asserts. 1348 if (DS->isSingleDecl()) 1349 return VisitDeclSubExpr(DS); 1350 1351 CFGBlock *B = 0; 1352 1353 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1354 typedef SmallVector<Decl*,10> BufTy; 1355 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1356 1357 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1358 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1359 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1360 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1361 1362 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1363 // automatically freed with the CFG. 1364 DeclGroupRef DG(*I); 1365 Decl *D = *I; 1366 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1367 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1368 1369 // Append the fake DeclStmt to block. 1370 B = VisitDeclSubExpr(DSNew); 1371 } 1372 1373 return B; 1374} 1375 1376/// VisitDeclSubExpr - Utility method to add block-level expressions for 1377/// DeclStmts and initializers in them. 1378CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1379 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1380 Decl *D = DS->getSingleDecl(); 1381 1382 if (isa<StaticAssertDecl>(D)) { 1383 // static_asserts aren't added to the CFG because they do not impact 1384 // runtime semantics. 1385 return Block; 1386 } 1387 1388 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1389 1390 if (!VD) { 1391 autoCreateBlock(); 1392 appendStmt(Block, DS); 1393 return Block; 1394 } 1395 1396 bool IsReference = false; 1397 bool HasTemporaries = false; 1398 1399 // Destructors of temporaries in initialization expression should be called 1400 // after initialization finishes. 1401 Expr *Init = VD->getInit(); 1402 if (Init) { 1403 IsReference = VD->getType()->isReferenceType(); 1404 HasTemporaries = isa<ExprWithCleanups>(Init); 1405 1406 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1407 // Generate destructors for temporaries in initialization expression. 1408 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1409 IsReference); 1410 } 1411 } 1412 1413 autoCreateBlock(); 1414 appendStmt(Block, DS); 1415 1416 if (Init) { 1417 if (HasTemporaries) 1418 // For expression with temporaries go directly to subexpression to omit 1419 // generating destructors for the second time. 1420 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1421 else 1422 Visit(Init); 1423 } 1424 1425 // If the type of VD is a VLA, then we must process its size expressions. 1426 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1427 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1428 Block = addStmt(VA->getSizeExpr()); 1429 1430 // Remove variable from local scope. 1431 if (ScopePos && VD == *ScopePos) 1432 ++ScopePos; 1433 1434 return Block; 1435} 1436 1437CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1438 // We may see an if statement in the middle of a basic block, or it may be the 1439 // first statement we are processing. In either case, we create a new basic 1440 // block. First, we create the blocks for the then...else statements, and 1441 // then we create the block containing the if statement. If we were in the 1442 // middle of a block, we stop processing that block. That block is then the 1443 // implicit successor for the "then" and "else" clauses. 1444 1445 // Save local scope position because in case of condition variable ScopePos 1446 // won't be restored when traversing AST. 1447 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1448 1449 // Create local scope for possible condition variable. 1450 // Store scope position. Add implicit destructor. 1451 if (VarDecl *VD = I->getConditionVariable()) { 1452 LocalScope::const_iterator BeginScopePos = ScopePos; 1453 addLocalScopeForVarDecl(VD); 1454 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1455 } 1456 1457 // The block we were processing is now finished. Make it the successor 1458 // block. 1459 if (Block) { 1460 Succ = Block; 1461 if (badCFG) 1462 return 0; 1463 } 1464 1465 // Process the false branch. 1466 CFGBlock *ElseBlock = Succ; 1467 1468 if (Stmt *Else = I->getElse()) { 1469 SaveAndRestore<CFGBlock*> sv(Succ); 1470 1471 // NULL out Block so that the recursive call to Visit will 1472 // create a new basic block. 1473 Block = NULL; 1474 1475 // If branch is not a compound statement create implicit scope 1476 // and add destructors. 1477 if (!isa<CompoundStmt>(Else)) 1478 addLocalScopeAndDtors(Else); 1479 1480 ElseBlock = addStmt(Else); 1481 1482 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1483 ElseBlock = sv.get(); 1484 else if (Block) { 1485 if (badCFG) 1486 return 0; 1487 } 1488 } 1489 1490 // Process the true branch. 1491 CFGBlock *ThenBlock; 1492 { 1493 Stmt *Then = I->getThen(); 1494 assert(Then); 1495 SaveAndRestore<CFGBlock*> sv(Succ); 1496 Block = NULL; 1497 1498 // If branch is not a compound statement create implicit scope 1499 // and add destructors. 1500 if (!isa<CompoundStmt>(Then)) 1501 addLocalScopeAndDtors(Then); 1502 1503 ThenBlock = addStmt(Then); 1504 1505 if (!ThenBlock) { 1506 // We can reach here if the "then" body has all NullStmts. 1507 // Create an empty block so we can distinguish between true and false 1508 // branches in path-sensitive analyses. 1509 ThenBlock = createBlock(false); 1510 addSuccessor(ThenBlock, sv.get()); 1511 } else if (Block) { 1512 if (badCFG) 1513 return 0; 1514 } 1515 } 1516 1517 // Now create a new block containing the if statement. 1518 Block = createBlock(false); 1519 1520 // Set the terminator of the new block to the If statement. 1521 Block->setTerminator(I); 1522 1523 // See if this is a known constant. 1524 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1525 1526 // Now add the successors. 1527 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1528 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1529 1530 // Add the condition as the last statement in the new block. This may create 1531 // new blocks as the condition may contain control-flow. Any newly created 1532 // blocks will be pointed to be "Block". 1533 Block = addStmt(I->getCond()); 1534 1535 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1536 // and the condition variable initialization to the CFG. 1537 if (VarDecl *VD = I->getConditionVariable()) { 1538 if (Expr *Init = VD->getInit()) { 1539 autoCreateBlock(); 1540 appendStmt(Block, I->getConditionVariableDeclStmt()); 1541 addStmt(Init); 1542 } 1543 } 1544 1545 return Block; 1546} 1547 1548 1549CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1550 // If we were in the middle of a block we stop processing that block. 1551 // 1552 // NOTE: If a "return" appears in the middle of a block, this means that the 1553 // code afterwards is DEAD (unreachable). We still keep a basic block 1554 // for that code; a simple "mark-and-sweep" from the entry block will be 1555 // able to report such dead blocks. 1556 1557 // Create the new block. 1558 Block = createBlock(false); 1559 1560 // The Exit block is the only successor. 1561 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1562 addSuccessor(Block, &cfg->getExit()); 1563 1564 // Add the return statement to the block. This may create new blocks if R 1565 // contains control-flow (short-circuit operations). 1566 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1567} 1568 1569CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1570 // Get the block of the labeled statement. Add it to our map. 1571 addStmt(L->getSubStmt()); 1572 CFGBlock *LabelBlock = Block; 1573 1574 if (!LabelBlock) // This can happen when the body is empty, i.e. 1575 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1576 1577 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1578 "label already in map"); 1579 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1580 1581 // Labels partition blocks, so this is the end of the basic block we were 1582 // processing (L is the block's label). Because this is label (and we have 1583 // already processed the substatement) there is no extra control-flow to worry 1584 // about. 1585 LabelBlock->setLabel(L); 1586 if (badCFG) 1587 return 0; 1588 1589 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1590 Block = NULL; 1591 1592 // This block is now the implicit successor of other blocks. 1593 Succ = LabelBlock; 1594 1595 return LabelBlock; 1596} 1597 1598CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1599 // Goto is a control-flow statement. Thus we stop processing the current 1600 // block and create a new one. 1601 1602 Block = createBlock(false); 1603 Block->setTerminator(G); 1604 1605 // If we already know the mapping to the label block add the successor now. 1606 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1607 1608 if (I == LabelMap.end()) 1609 // We will need to backpatch this block later. 1610 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1611 else { 1612 JumpTarget JT = I->second; 1613 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1614 addSuccessor(Block, JT.block); 1615 } 1616 1617 return Block; 1618} 1619 1620CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1621 CFGBlock *LoopSuccessor = NULL; 1622 1623 // Save local scope position because in case of condition variable ScopePos 1624 // won't be restored when traversing AST. 1625 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1626 1627 // Create local scope for init statement and possible condition variable. 1628 // Add destructor for init statement and condition variable. 1629 // Store scope position for continue statement. 1630 if (Stmt *Init = F->getInit()) 1631 addLocalScopeForStmt(Init); 1632 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1633 1634 if (VarDecl *VD = F->getConditionVariable()) 1635 addLocalScopeForVarDecl(VD); 1636 LocalScope::const_iterator ContinueScopePos = ScopePos; 1637 1638 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1639 1640 // "for" is a control-flow statement. Thus we stop processing the current 1641 // block. 1642 if (Block) { 1643 if (badCFG) 1644 return 0; 1645 LoopSuccessor = Block; 1646 } else 1647 LoopSuccessor = Succ; 1648 1649 // Save the current value for the break targets. 1650 // All breaks should go to the code following the loop. 1651 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1652 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1653 1654 // Because of short-circuit evaluation, the condition of the loop can span 1655 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1656 // evaluate the condition. 1657 CFGBlock *ExitConditionBlock = createBlock(false); 1658 CFGBlock *EntryConditionBlock = ExitConditionBlock; 1659 1660 // Set the terminator for the "exit" condition block. 1661 ExitConditionBlock->setTerminator(F); 1662 1663 // Now add the actual condition to the condition block. Because the condition 1664 // itself may contain control-flow, new blocks may be created. 1665 if (Stmt *C = F->getCond()) { 1666 Block = ExitConditionBlock; 1667 EntryConditionBlock = addStmt(C); 1668 if (badCFG) 1669 return 0; 1670 assert(Block == EntryConditionBlock || 1671 (Block == 0 && EntryConditionBlock == Succ)); 1672 1673 // If this block contains a condition variable, add both the condition 1674 // variable and initializer to the CFG. 1675 if (VarDecl *VD = F->getConditionVariable()) { 1676 if (Expr *Init = VD->getInit()) { 1677 autoCreateBlock(); 1678 appendStmt(Block, F->getConditionVariableDeclStmt()); 1679 EntryConditionBlock = addStmt(Init); 1680 assert(Block == EntryConditionBlock); 1681 } 1682 } 1683 1684 if (Block) { 1685 if (badCFG) 1686 return 0; 1687 } 1688 } 1689 1690 // The condition block is the implicit successor for the loop body as well as 1691 // any code above the loop. 1692 Succ = EntryConditionBlock; 1693 1694 // See if this is a known constant. 1695 TryResult KnownVal(true); 1696 1697 if (F->getCond()) 1698 KnownVal = tryEvaluateBool(F->getCond()); 1699 1700 // Now create the loop body. 1701 { 1702 assert(F->getBody()); 1703 1704 // Save the current values for Block, Succ, and continue targets. 1705 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1706 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1707 1708 // Create a new block to contain the (bottom) of the loop body. 1709 Block = NULL; 1710 1711 // Loop body should end with destructor of Condition variable (if any). 1712 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1713 1714 if (Stmt *I = F->getInc()) { 1715 // Generate increment code in its own basic block. This is the target of 1716 // continue statements. 1717 Succ = addStmt(I); 1718 } else { 1719 // No increment code. Create a special, empty, block that is used as the 1720 // target block for "looping back" to the start of the loop. 1721 assert(Succ == EntryConditionBlock); 1722 Succ = Block ? Block : createBlock(); 1723 } 1724 1725 // Finish up the increment (or empty) block if it hasn't been already. 1726 if (Block) { 1727 assert(Block == Succ); 1728 if (badCFG) 1729 return 0; 1730 Block = 0; 1731 } 1732 1733 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1734 1735 // The starting block for the loop increment is the block that should 1736 // represent the 'loop target' for looping back to the start of the loop. 1737 ContinueJumpTarget.block->setLoopTarget(F); 1738 1739 // If body is not a compound statement create implicit scope 1740 // and add destructors. 1741 if (!isa<CompoundStmt>(F->getBody())) 1742 addLocalScopeAndDtors(F->getBody()); 1743 1744 // Now populate the body block, and in the process create new blocks as we 1745 // walk the body of the loop. 1746 CFGBlock *BodyBlock = addStmt(F->getBody()); 1747 1748 if (!BodyBlock) 1749 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1750 else if (badCFG) 1751 return 0; 1752 1753 // This new body block is a successor to our "exit" condition block. 1754 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1755 } 1756 1757 // Link up the condition block with the code that follows the loop. (the 1758 // false branch). 1759 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1760 1761 // If the loop contains initialization, create a new block for those 1762 // statements. This block can also contain statements that precede the loop. 1763 if (Stmt *I = F->getInit()) { 1764 Block = createBlock(); 1765 return addStmt(I); 1766 } 1767 1768 // There is no loop initialization. We are thus basically a while loop. 1769 // NULL out Block to force lazy block construction. 1770 Block = NULL; 1771 Succ = EntryConditionBlock; 1772 return EntryConditionBlock; 1773} 1774 1775CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1776 if (asc.alwaysAdd(*this, M)) { 1777 autoCreateBlock(); 1778 appendStmt(Block, M); 1779 } 1780 return Visit(M->getBase()); 1781} 1782 1783CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 1784 // Objective-C fast enumeration 'for' statements: 1785 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1786 // 1787 // for ( Type newVariable in collection_expression ) { statements } 1788 // 1789 // becomes: 1790 // 1791 // prologue: 1792 // 1. collection_expression 1793 // T. jump to loop_entry 1794 // loop_entry: 1795 // 1. side-effects of element expression 1796 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1797 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1798 // TB: 1799 // statements 1800 // T. jump to loop_entry 1801 // FB: 1802 // what comes after 1803 // 1804 // and 1805 // 1806 // Type existingItem; 1807 // for ( existingItem in expression ) { statements } 1808 // 1809 // becomes: 1810 // 1811 // the same with newVariable replaced with existingItem; the binding works 1812 // the same except that for one ObjCForCollectionStmt::getElement() returns 1813 // a DeclStmt and the other returns a DeclRefExpr. 1814 // 1815 1816 CFGBlock *LoopSuccessor = 0; 1817 1818 if (Block) { 1819 if (badCFG) 1820 return 0; 1821 LoopSuccessor = Block; 1822 Block = 0; 1823 } else 1824 LoopSuccessor = Succ; 1825 1826 // Build the condition blocks. 1827 CFGBlock *ExitConditionBlock = createBlock(false); 1828 1829 // Set the terminator for the "exit" condition block. 1830 ExitConditionBlock->setTerminator(S); 1831 1832 // The last statement in the block should be the ObjCForCollectionStmt, which 1833 // performs the actual binding to 'element' and determines if there are any 1834 // more items in the collection. 1835 appendStmt(ExitConditionBlock, S); 1836 Block = ExitConditionBlock; 1837 1838 // Walk the 'element' expression to see if there are any side-effects. We 1839 // generate new blocks as necessary. We DON'T add the statement by default to 1840 // the CFG unless it contains control-flow. 1841 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 1842 AddStmtChoice::NotAlwaysAdd); 1843 if (Block) { 1844 if (badCFG) 1845 return 0; 1846 Block = 0; 1847 } 1848 1849 // The condition block is the implicit successor for the loop body as well as 1850 // any code above the loop. 1851 Succ = EntryConditionBlock; 1852 1853 // Now create the true branch. 1854 { 1855 // Save the current values for Succ, continue and break targets. 1856 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1857 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1858 save_break(BreakJumpTarget); 1859 1860 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1861 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1862 1863 CFGBlock *BodyBlock = addStmt(S->getBody()); 1864 1865 if (!BodyBlock) 1866 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1867 else if (Block) { 1868 if (badCFG) 1869 return 0; 1870 } 1871 1872 // This new body block is a successor to our "exit" condition block. 1873 addSuccessor(ExitConditionBlock, BodyBlock); 1874 } 1875 1876 // Link up the condition block with the code that follows the loop. 1877 // (the false branch). 1878 addSuccessor(ExitConditionBlock, LoopSuccessor); 1879 1880 // Now create a prologue block to contain the collection expression. 1881 Block = createBlock(); 1882 return addStmt(S->getCollection()); 1883} 1884 1885CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 1886 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1887 1888 // Inline the body. 1889 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1890 1891 // The sync body starts its own basic block. This makes it a little easier 1892 // for diagnostic clients. 1893 if (SyncBlock) { 1894 if (badCFG) 1895 return 0; 1896 1897 Block = 0; 1898 Succ = SyncBlock; 1899 } 1900 1901 // Add the @synchronized to the CFG. 1902 autoCreateBlock(); 1903 appendStmt(Block, S); 1904 1905 // Inline the sync expression. 1906 return addStmt(S->getSynchExpr()); 1907} 1908 1909CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 1910 // FIXME 1911 return NYS(); 1912} 1913 1914CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) { 1915 autoCreateBlock(); 1916 1917 // Add the PseudoObject as the last thing. 1918 appendStmt(Block, E); 1919 1920 CFGBlock *lastBlock = Block; 1921 1922 // Before that, evaluate all of the semantics in order. In 1923 // CFG-land, that means appending them in reverse order. 1924 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) { 1925 Expr *Semantic = E->getSemanticExpr(--i); 1926 1927 // If the semantic is an opaque value, we're being asked to bind 1928 // it to its source expression. 1929 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic)) 1930 Semantic = OVE->getSourceExpr(); 1931 1932 if (CFGBlock *B = Visit(Semantic)) 1933 lastBlock = B; 1934 } 1935 1936 return lastBlock; 1937} 1938 1939CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 1940 CFGBlock *LoopSuccessor = NULL; 1941 1942 // Save local scope position because in case of condition variable ScopePos 1943 // won't be restored when traversing AST. 1944 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1945 1946 // Create local scope for possible condition variable. 1947 // Store scope position for continue statement. 1948 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1949 if (VarDecl *VD = W->getConditionVariable()) { 1950 addLocalScopeForVarDecl(VD); 1951 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1952 } 1953 1954 // "while" is a control-flow statement. Thus we stop processing the current 1955 // block. 1956 if (Block) { 1957 if (badCFG) 1958 return 0; 1959 LoopSuccessor = Block; 1960 Block = 0; 1961 } else 1962 LoopSuccessor = Succ; 1963 1964 // Because of short-circuit evaluation, the condition of the loop can span 1965 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1966 // evaluate the condition. 1967 CFGBlock *ExitConditionBlock = createBlock(false); 1968 CFGBlock *EntryConditionBlock = ExitConditionBlock; 1969 1970 // Set the terminator for the "exit" condition block. 1971 ExitConditionBlock->setTerminator(W); 1972 1973 // Now add the actual condition to the condition block. Because the condition 1974 // itself may contain control-flow, new blocks may be created. Thus we update 1975 // "Succ" after adding the condition. 1976 if (Stmt *C = W->getCond()) { 1977 Block = ExitConditionBlock; 1978 EntryConditionBlock = addStmt(C); 1979 // The condition might finish the current 'Block'. 1980 Block = EntryConditionBlock; 1981 1982 // If this block contains a condition variable, add both the condition 1983 // variable and initializer to the CFG. 1984 if (VarDecl *VD = W->getConditionVariable()) { 1985 if (Expr *Init = VD->getInit()) { 1986 autoCreateBlock(); 1987 appendStmt(Block, W->getConditionVariableDeclStmt()); 1988 EntryConditionBlock = addStmt(Init); 1989 assert(Block == EntryConditionBlock); 1990 } 1991 } 1992 1993 if (Block) { 1994 if (badCFG) 1995 return 0; 1996 } 1997 } 1998 1999 // The condition block is the implicit successor for the loop body as well as 2000 // any code above the loop. 2001 Succ = EntryConditionBlock; 2002 2003 // See if this is a known constant. 2004 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 2005 2006 // Process the loop body. 2007 { 2008 assert(W->getBody()); 2009 2010 // Save the current values for Block, Succ, and continue and break targets 2011 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2012 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2013 save_break(BreakJumpTarget); 2014 2015 // Create an empty block to represent the transition block for looping back 2016 // to the head of the loop. 2017 Block = 0; 2018 assert(Succ == EntryConditionBlock); 2019 Succ = createBlock(); 2020 Succ->setLoopTarget(W); 2021 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 2022 2023 // All breaks should go to the code following the loop. 2024 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2025 2026 // NULL out Block to force lazy instantiation of blocks for the body. 2027 Block = NULL; 2028 2029 // Loop body should end with destructor of Condition variable (if any). 2030 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2031 2032 // If body is not a compound statement create implicit scope 2033 // and add destructors. 2034 if (!isa<CompoundStmt>(W->getBody())) 2035 addLocalScopeAndDtors(W->getBody()); 2036 2037 // Create the body. The returned block is the entry to the loop body. 2038 CFGBlock *BodyBlock = addStmt(W->getBody()); 2039 2040 if (!BodyBlock) 2041 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2042 else if (Block) { 2043 if (badCFG) 2044 return 0; 2045 } 2046 2047 // Add the loop body entry as a successor to the condition. 2048 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2049 } 2050 2051 // Link up the condition block with the code that follows the loop. (the 2052 // false branch). 2053 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2054 2055 // There can be no more statements in the condition block since we loop back 2056 // to this block. NULL out Block to force lazy creation of another block. 2057 Block = NULL; 2058 2059 // Return the condition block, which is the dominating block for the loop. 2060 Succ = EntryConditionBlock; 2061 return EntryConditionBlock; 2062} 2063 2064 2065CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2066 // FIXME: For now we pretend that @catch and the code it contains does not 2067 // exit. 2068 return Block; 2069} 2070 2071CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2072 // FIXME: This isn't complete. We basically treat @throw like a return 2073 // statement. 2074 2075 // If we were in the middle of a block we stop processing that block. 2076 if (badCFG) 2077 return 0; 2078 2079 // Create the new block. 2080 Block = createBlock(false); 2081 2082 // The Exit block is the only successor. 2083 addSuccessor(Block, &cfg->getExit()); 2084 2085 // Add the statement to the block. This may create new blocks if S contains 2086 // control-flow (short-circuit operations). 2087 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2088} 2089 2090CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2091 // If we were in the middle of a block we stop processing that block. 2092 if (badCFG) 2093 return 0; 2094 2095 // Create the new block. 2096 Block = createBlock(false); 2097 2098 if (TryTerminatedBlock) 2099 // The current try statement is the only successor. 2100 addSuccessor(Block, TryTerminatedBlock); 2101 else 2102 // otherwise the Exit block is the only successor. 2103 addSuccessor(Block, &cfg->getExit()); 2104 2105 // Add the statement to the block. This may create new blocks if S contains 2106 // control-flow (short-circuit operations). 2107 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2108} 2109 2110CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2111 CFGBlock *LoopSuccessor = NULL; 2112 2113 // "do...while" is a control-flow statement. Thus we stop processing the 2114 // current block. 2115 if (Block) { 2116 if (badCFG) 2117 return 0; 2118 LoopSuccessor = Block; 2119 } else 2120 LoopSuccessor = Succ; 2121 2122 // Because of short-circuit evaluation, the condition of the loop can span 2123 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2124 // evaluate the condition. 2125 CFGBlock *ExitConditionBlock = createBlock(false); 2126 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2127 2128 // Set the terminator for the "exit" condition block. 2129 ExitConditionBlock->setTerminator(D); 2130 2131 // Now add the actual condition to the condition block. Because the condition 2132 // itself may contain control-flow, new blocks may be created. 2133 if (Stmt *C = D->getCond()) { 2134 Block = ExitConditionBlock; 2135 EntryConditionBlock = addStmt(C); 2136 if (Block) { 2137 if (badCFG) 2138 return 0; 2139 } 2140 } 2141 2142 // The condition block is the implicit successor for the loop body. 2143 Succ = EntryConditionBlock; 2144 2145 // See if this is a known constant. 2146 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2147 2148 // Process the loop body. 2149 CFGBlock *BodyBlock = NULL; 2150 { 2151 assert(D->getBody()); 2152 2153 // Save the current values for Block, Succ, and continue and break targets 2154 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2155 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2156 save_break(BreakJumpTarget); 2157 2158 // All continues within this loop should go to the condition block 2159 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2160 2161 // All breaks should go to the code following the loop. 2162 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2163 2164 // NULL out Block to force lazy instantiation of blocks for the body. 2165 Block = NULL; 2166 2167 // If body is not a compound statement create implicit scope 2168 // and add destructors. 2169 if (!isa<CompoundStmt>(D->getBody())) 2170 addLocalScopeAndDtors(D->getBody()); 2171 2172 // Create the body. The returned block is the entry to the loop body. 2173 BodyBlock = addStmt(D->getBody()); 2174 2175 if (!BodyBlock) 2176 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2177 else if (Block) { 2178 if (badCFG) 2179 return 0; 2180 } 2181 2182 if (!KnownVal.isFalse()) { 2183 // Add an intermediate block between the BodyBlock and the 2184 // ExitConditionBlock to represent the "loop back" transition. Create an 2185 // empty block to represent the transition block for looping back to the 2186 // head of the loop. 2187 // FIXME: Can we do this more efficiently without adding another block? 2188 Block = NULL; 2189 Succ = BodyBlock; 2190 CFGBlock *LoopBackBlock = createBlock(); 2191 LoopBackBlock->setLoopTarget(D); 2192 2193 // Add the loop body entry as a successor to the condition. 2194 addSuccessor(ExitConditionBlock, LoopBackBlock); 2195 } 2196 else 2197 addSuccessor(ExitConditionBlock, NULL); 2198 } 2199 2200 // Link up the condition block with the code that follows the loop. 2201 // (the false branch). 2202 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2203 2204 // There can be no more statements in the body block(s) since we loop back to 2205 // the body. NULL out Block to force lazy creation of another block. 2206 Block = NULL; 2207 2208 // Return the loop body, which is the dominating block for the loop. 2209 Succ = BodyBlock; 2210 return BodyBlock; 2211} 2212 2213CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2214 // "continue" is a control-flow statement. Thus we stop processing the 2215 // current block. 2216 if (badCFG) 2217 return 0; 2218 2219 // Now create a new block that ends with the continue statement. 2220 Block = createBlock(false); 2221 Block->setTerminator(C); 2222 2223 // If there is no target for the continue, then we are looking at an 2224 // incomplete AST. This means the CFG cannot be constructed. 2225 if (ContinueJumpTarget.block) { 2226 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2227 addSuccessor(Block, ContinueJumpTarget.block); 2228 } else 2229 badCFG = true; 2230 2231 return Block; 2232} 2233 2234CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2235 AddStmtChoice asc) { 2236 2237 if (asc.alwaysAdd(*this, E)) { 2238 autoCreateBlock(); 2239 appendStmt(Block, E); 2240 } 2241 2242 // VLA types have expressions that must be evaluated. 2243 CFGBlock *lastBlock = Block; 2244 2245 if (E->isArgumentType()) { 2246 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2247 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2248 lastBlock = addStmt(VA->getSizeExpr()); 2249 } 2250 return lastBlock; 2251} 2252 2253/// VisitStmtExpr - Utility method to handle (nested) statement 2254/// expressions (a GCC extension). 2255CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2256 if (asc.alwaysAdd(*this, SE)) { 2257 autoCreateBlock(); 2258 appendStmt(Block, SE); 2259 } 2260 return VisitCompoundStmt(SE->getSubStmt()); 2261} 2262 2263CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2264 // "switch" is a control-flow statement. Thus we stop processing the current 2265 // block. 2266 CFGBlock *SwitchSuccessor = NULL; 2267 2268 // Save local scope position because in case of condition variable ScopePos 2269 // won't be restored when traversing AST. 2270 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2271 2272 // Create local scope for possible condition variable. 2273 // Store scope position. Add implicit destructor. 2274 if (VarDecl *VD = Terminator->getConditionVariable()) { 2275 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2276 addLocalScopeForVarDecl(VD); 2277 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2278 } 2279 2280 if (Block) { 2281 if (badCFG) 2282 return 0; 2283 SwitchSuccessor = Block; 2284 } else SwitchSuccessor = Succ; 2285 2286 // Save the current "switch" context. 2287 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2288 save_default(DefaultCaseBlock); 2289 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2290 2291 // Set the "default" case to be the block after the switch statement. If the 2292 // switch statement contains a "default:", this value will be overwritten with 2293 // the block for that code. 2294 DefaultCaseBlock = SwitchSuccessor; 2295 2296 // Create a new block that will contain the switch statement. 2297 SwitchTerminatedBlock = createBlock(false); 2298 2299 // Now process the switch body. The code after the switch is the implicit 2300 // successor. 2301 Succ = SwitchSuccessor; 2302 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2303 2304 // When visiting the body, the case statements should automatically get linked 2305 // up to the switch. We also don't keep a pointer to the body, since all 2306 // control-flow from the switch goes to case/default statements. 2307 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2308 Block = NULL; 2309 2310 // For pruning unreachable case statements, save the current state 2311 // for tracking the condition value. 2312 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2313 false); 2314 2315 // Determine if the switch condition can be explicitly evaluated. 2316 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2317 Expr::EvalResult result; 2318 bool b = tryEvaluate(Terminator->getCond(), result); 2319 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2320 b ? &result : 0); 2321 2322 // If body is not a compound statement create implicit scope 2323 // and add destructors. 2324 if (!isa<CompoundStmt>(Terminator->getBody())) 2325 addLocalScopeAndDtors(Terminator->getBody()); 2326 2327 addStmt(Terminator->getBody()); 2328 if (Block) { 2329 if (badCFG) 2330 return 0; 2331 } 2332 2333 // If we have no "default:" case, the default transition is to the code 2334 // following the switch body. Moreover, take into account if all the 2335 // cases of a switch are covered (e.g., switching on an enum value). 2336 addSuccessor(SwitchTerminatedBlock, 2337 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2338 ? 0 : DefaultCaseBlock); 2339 2340 // Add the terminator and condition in the switch block. 2341 SwitchTerminatedBlock->setTerminator(Terminator); 2342 Block = SwitchTerminatedBlock; 2343 Block = addStmt(Terminator->getCond()); 2344 2345 // Finally, if the SwitchStmt contains a condition variable, add both the 2346 // SwitchStmt and the condition variable initialization to the CFG. 2347 if (VarDecl *VD = Terminator->getConditionVariable()) { 2348 if (Expr *Init = VD->getInit()) { 2349 autoCreateBlock(); 2350 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2351 addStmt(Init); 2352 } 2353 } 2354 2355 return Block; 2356} 2357 2358static bool shouldAddCase(bool &switchExclusivelyCovered, 2359 const Expr::EvalResult *switchCond, 2360 const CaseStmt *CS, 2361 ASTContext &Ctx) { 2362 if (!switchCond) 2363 return true; 2364 2365 bool addCase = false; 2366 2367 if (!switchExclusivelyCovered) { 2368 if (switchCond->Val.isInt()) { 2369 // Evaluate the LHS of the case value. 2370 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2371 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2372 2373 if (condInt == lhsInt) { 2374 addCase = true; 2375 switchExclusivelyCovered = true; 2376 } 2377 else if (condInt < lhsInt) { 2378 if (const Expr *RHS = CS->getRHS()) { 2379 // Evaluate the RHS of the case value. 2380 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2381 if (V2 <= condInt) { 2382 addCase = true; 2383 switchExclusivelyCovered = true; 2384 } 2385 } 2386 } 2387 } 2388 else 2389 addCase = true; 2390 } 2391 return addCase; 2392} 2393 2394CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2395 // CaseStmts are essentially labels, so they are the first statement in a 2396 // block. 2397 CFGBlock *TopBlock = 0, *LastBlock = 0; 2398 2399 if (Stmt *Sub = CS->getSubStmt()) { 2400 // For deeply nested chains of CaseStmts, instead of doing a recursion 2401 // (which can blow out the stack), manually unroll and create blocks 2402 // along the way. 2403 while (isa<CaseStmt>(Sub)) { 2404 CFGBlock *currentBlock = createBlock(false); 2405 currentBlock->setLabel(CS); 2406 2407 if (TopBlock) 2408 addSuccessor(LastBlock, currentBlock); 2409 else 2410 TopBlock = currentBlock; 2411 2412 addSuccessor(SwitchTerminatedBlock, 2413 shouldAddCase(switchExclusivelyCovered, switchCond, 2414 CS, *Context) 2415 ? currentBlock : 0); 2416 2417 LastBlock = currentBlock; 2418 CS = cast<CaseStmt>(Sub); 2419 Sub = CS->getSubStmt(); 2420 } 2421 2422 addStmt(Sub); 2423 } 2424 2425 CFGBlock *CaseBlock = Block; 2426 if (!CaseBlock) 2427 CaseBlock = createBlock(); 2428 2429 // Cases statements partition blocks, so this is the top of the basic block we 2430 // were processing (the "case XXX:" is the label). 2431 CaseBlock->setLabel(CS); 2432 2433 if (badCFG) 2434 return 0; 2435 2436 // Add this block to the list of successors for the block with the switch 2437 // statement. 2438 assert(SwitchTerminatedBlock); 2439 addSuccessor(SwitchTerminatedBlock, 2440 shouldAddCase(switchExclusivelyCovered, switchCond, 2441 CS, *Context) 2442 ? CaseBlock : 0); 2443 2444 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2445 Block = NULL; 2446 2447 if (TopBlock) { 2448 addSuccessor(LastBlock, CaseBlock); 2449 Succ = TopBlock; 2450 } else { 2451 // This block is now the implicit successor of other blocks. 2452 Succ = CaseBlock; 2453 } 2454 2455 return Succ; 2456} 2457 2458CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2459 if (Terminator->getSubStmt()) 2460 addStmt(Terminator->getSubStmt()); 2461 2462 DefaultCaseBlock = Block; 2463 2464 if (!DefaultCaseBlock) 2465 DefaultCaseBlock = createBlock(); 2466 2467 // Default statements partition blocks, so this is the top of the basic block 2468 // we were processing (the "default:" is the label). 2469 DefaultCaseBlock->setLabel(Terminator); 2470 2471 if (badCFG) 2472 return 0; 2473 2474 // Unlike case statements, we don't add the default block to the successors 2475 // for the switch statement immediately. This is done when we finish 2476 // processing the switch statement. This allows for the default case 2477 // (including a fall-through to the code after the switch statement) to always 2478 // be the last successor of a switch-terminated block. 2479 2480 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2481 Block = NULL; 2482 2483 // This block is now the implicit successor of other blocks. 2484 Succ = DefaultCaseBlock; 2485 2486 return DefaultCaseBlock; 2487} 2488 2489CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2490 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2491 // current block. 2492 CFGBlock *TrySuccessor = NULL; 2493 2494 if (Block) { 2495 if (badCFG) 2496 return 0; 2497 TrySuccessor = Block; 2498 } else TrySuccessor = Succ; 2499 2500 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2501 2502 // Create a new block that will contain the try statement. 2503 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2504 // Add the terminator in the try block. 2505 NewTryTerminatedBlock->setTerminator(Terminator); 2506 2507 bool HasCatchAll = false; 2508 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2509 // The code after the try is the implicit successor. 2510 Succ = TrySuccessor; 2511 CXXCatchStmt *CS = Terminator->getHandler(h); 2512 if (CS->getExceptionDecl() == 0) { 2513 HasCatchAll = true; 2514 } 2515 Block = NULL; 2516 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2517 if (CatchBlock == 0) 2518 return 0; 2519 // Add this block to the list of successors for the block with the try 2520 // statement. 2521 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2522 } 2523 if (!HasCatchAll) { 2524 if (PrevTryTerminatedBlock) 2525 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2526 else 2527 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2528 } 2529 2530 // The code after the try is the implicit successor. 2531 Succ = TrySuccessor; 2532 2533 // Save the current "try" context. 2534 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2535 cfg->addTryDispatchBlock(TryTerminatedBlock); 2536 2537 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2538 Block = NULL; 2539 Block = addStmt(Terminator->getTryBlock()); 2540 return Block; 2541} 2542 2543CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2544 // CXXCatchStmt are treated like labels, so they are the first statement in a 2545 // block. 2546 2547 // Save local scope position because in case of exception variable ScopePos 2548 // won't be restored when traversing AST. 2549 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2550 2551 // Create local scope for possible exception variable. 2552 // Store scope position. Add implicit destructor. 2553 if (VarDecl *VD = CS->getExceptionDecl()) { 2554 LocalScope::const_iterator BeginScopePos = ScopePos; 2555 addLocalScopeForVarDecl(VD); 2556 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2557 } 2558 2559 if (CS->getHandlerBlock()) 2560 addStmt(CS->getHandlerBlock()); 2561 2562 CFGBlock *CatchBlock = Block; 2563 if (!CatchBlock) 2564 CatchBlock = createBlock(); 2565 2566 CatchBlock->setLabel(CS); 2567 2568 if (badCFG) 2569 return 0; 2570 2571 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2572 Block = NULL; 2573 2574 return CatchBlock; 2575} 2576 2577CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2578 // C++0x for-range statements are specified as [stmt.ranged]: 2579 // 2580 // { 2581 // auto && __range = range-init; 2582 // for ( auto __begin = begin-expr, 2583 // __end = end-expr; 2584 // __begin != __end; 2585 // ++__begin ) { 2586 // for-range-declaration = *__begin; 2587 // statement 2588 // } 2589 // } 2590 2591 // Save local scope position before the addition of the implicit variables. 2592 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2593 2594 // Create local scopes and destructors for range, begin and end variables. 2595 if (Stmt *Range = S->getRangeStmt()) 2596 addLocalScopeForStmt(Range); 2597 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2598 addLocalScopeForStmt(BeginEnd); 2599 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2600 2601 LocalScope::const_iterator ContinueScopePos = ScopePos; 2602 2603 // "for" is a control-flow statement. Thus we stop processing the current 2604 // block. 2605 CFGBlock *LoopSuccessor = NULL; 2606 if (Block) { 2607 if (badCFG) 2608 return 0; 2609 LoopSuccessor = Block; 2610 } else 2611 LoopSuccessor = Succ; 2612 2613 // Save the current value for the break targets. 2614 // All breaks should go to the code following the loop. 2615 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2616 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2617 2618 // The block for the __begin != __end expression. 2619 CFGBlock *ConditionBlock = createBlock(false); 2620 ConditionBlock->setTerminator(S); 2621 2622 // Now add the actual condition to the condition block. 2623 if (Expr *C = S->getCond()) { 2624 Block = ConditionBlock; 2625 CFGBlock *BeginConditionBlock = addStmt(C); 2626 if (badCFG) 2627 return 0; 2628 assert(BeginConditionBlock == ConditionBlock && 2629 "condition block in for-range was unexpectedly complex"); 2630 (void)BeginConditionBlock; 2631 } 2632 2633 // The condition block is the implicit successor for the loop body as well as 2634 // any code above the loop. 2635 Succ = ConditionBlock; 2636 2637 // See if this is a known constant. 2638 TryResult KnownVal(true); 2639 2640 if (S->getCond()) 2641 KnownVal = tryEvaluateBool(S->getCond()); 2642 2643 // Now create the loop body. 2644 { 2645 assert(S->getBody()); 2646 2647 // Save the current values for Block, Succ, and continue targets. 2648 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2649 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2650 2651 // Generate increment code in its own basic block. This is the target of 2652 // continue statements. 2653 Block = 0; 2654 Succ = addStmt(S->getInc()); 2655 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2656 2657 // The starting block for the loop increment is the block that should 2658 // represent the 'loop target' for looping back to the start of the loop. 2659 ContinueJumpTarget.block->setLoopTarget(S); 2660 2661 // Finish up the increment block and prepare to start the loop body. 2662 assert(Block); 2663 if (badCFG) 2664 return 0; 2665 Block = 0; 2666 2667 2668 // Add implicit scope and dtors for loop variable. 2669 addLocalScopeAndDtors(S->getLoopVarStmt()); 2670 2671 // Populate a new block to contain the loop body and loop variable. 2672 Block = addStmt(S->getBody()); 2673 if (badCFG) 2674 return 0; 2675 Block = addStmt(S->getLoopVarStmt()); 2676 if (badCFG) 2677 return 0; 2678 2679 // This new body block is a successor to our condition block. 2680 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2681 } 2682 2683 // Link up the condition block with the code that follows the loop (the 2684 // false branch). 2685 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2686 2687 // Add the initialization statements. 2688 Block = createBlock(); 2689 addStmt(S->getBeginEndStmt()); 2690 return addStmt(S->getRangeStmt()); 2691} 2692 2693CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2694 AddStmtChoice asc) { 2695 if (BuildOpts.AddImplicitDtors) { 2696 // If adding implicit destructors visit the full expression for adding 2697 // destructors of temporaries. 2698 VisitForTemporaryDtors(E->getSubExpr()); 2699 2700 // Full expression has to be added as CFGStmt so it will be sequenced 2701 // before destructors of it's temporaries. 2702 asc = asc.withAlwaysAdd(true); 2703 } 2704 return Visit(E->getSubExpr(), asc); 2705} 2706 2707CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2708 AddStmtChoice asc) { 2709 if (asc.alwaysAdd(*this, E)) { 2710 autoCreateBlock(); 2711 appendStmt(Block, E); 2712 2713 // We do not want to propagate the AlwaysAdd property. 2714 asc = asc.withAlwaysAdd(false); 2715 } 2716 return Visit(E->getSubExpr(), asc); 2717} 2718 2719CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2720 AddStmtChoice asc) { 2721 autoCreateBlock(); 2722 if (!C->isElidable()) 2723 appendStmt(Block, C); 2724 2725 return VisitChildren(C); 2726} 2727 2728CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2729 AddStmtChoice asc) { 2730 if (asc.alwaysAdd(*this, E)) { 2731 autoCreateBlock(); 2732 appendStmt(Block, E); 2733 // We do not want to propagate the AlwaysAdd property. 2734 asc = asc.withAlwaysAdd(false); 2735 } 2736 return Visit(E->getSubExpr(), asc); 2737} 2738 2739CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2740 AddStmtChoice asc) { 2741 autoCreateBlock(); 2742 appendStmt(Block, C); 2743 return VisitChildren(C); 2744} 2745 2746CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2747 AddStmtChoice asc) { 2748 if (asc.alwaysAdd(*this, E)) { 2749 autoCreateBlock(); 2750 appendStmt(Block, E); 2751 } 2752 return Visit(E->getSubExpr(), AddStmtChoice()); 2753} 2754 2755CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 2756 // Lazily create the indirect-goto dispatch block if there isn't one already. 2757 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 2758 2759 if (!IBlock) { 2760 IBlock = createBlock(false); 2761 cfg->setIndirectGotoBlock(IBlock); 2762 } 2763 2764 // IndirectGoto is a control-flow statement. Thus we stop processing the 2765 // current block and create a new one. 2766 if (badCFG) 2767 return 0; 2768 2769 Block = createBlock(false); 2770 Block->setTerminator(I); 2771 addSuccessor(Block, IBlock); 2772 return addStmt(I->getTarget()); 2773} 2774 2775CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2776tryAgain: 2777 if (!E) { 2778 badCFG = true; 2779 return NULL; 2780 } 2781 switch (E->getStmtClass()) { 2782 default: 2783 return VisitChildrenForTemporaryDtors(E); 2784 2785 case Stmt::BinaryOperatorClass: 2786 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2787 2788 case Stmt::CXXBindTemporaryExprClass: 2789 return VisitCXXBindTemporaryExprForTemporaryDtors( 2790 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2791 2792 case Stmt::BinaryConditionalOperatorClass: 2793 case Stmt::ConditionalOperatorClass: 2794 return VisitConditionalOperatorForTemporaryDtors( 2795 cast<AbstractConditionalOperator>(E), BindToTemporary); 2796 2797 case Stmt::ImplicitCastExprClass: 2798 // For implicit cast we want BindToTemporary to be passed further. 2799 E = cast<CastExpr>(E)->getSubExpr(); 2800 goto tryAgain; 2801 2802 case Stmt::ParenExprClass: 2803 E = cast<ParenExpr>(E)->getSubExpr(); 2804 goto tryAgain; 2805 2806 case Stmt::MaterializeTemporaryExprClass: 2807 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 2808 goto tryAgain; 2809 } 2810} 2811 2812CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2813 // When visiting children for destructors we want to visit them in reverse 2814 // order. Because there's no reverse iterator for children must to reverse 2815 // them in helper vector. 2816 typedef SmallVector<Stmt *, 4> ChildrenVect; 2817 ChildrenVect ChildrenRev; 2818 for (Stmt::child_range I = E->children(); I; ++I) { 2819 if (*I) ChildrenRev.push_back(*I); 2820 } 2821 2822 CFGBlock *B = Block; 2823 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2824 L = ChildrenRev.rend(); I != L; ++I) { 2825 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2826 B = R; 2827 } 2828 return B; 2829} 2830 2831CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2832 if (E->isLogicalOp()) { 2833 // Destructors for temporaries in LHS expression should be called after 2834 // those for RHS expression. Even if this will unnecessarily create a block, 2835 // this block will be used at least by the full expression. 2836 autoCreateBlock(); 2837 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2838 if (badCFG) 2839 return NULL; 2840 2841 Succ = ConfluenceBlock; 2842 Block = NULL; 2843 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2844 2845 if (RHSBlock) { 2846 if (badCFG) 2847 return NULL; 2848 2849 // If RHS expression did produce destructors we need to connect created 2850 // blocks to CFG in same manner as for binary operator itself. 2851 CFGBlock *LHSBlock = createBlock(false); 2852 LHSBlock->setTerminator(CFGTerminator(E, true)); 2853 2854 // For binary operator LHS block is before RHS in list of predecessors 2855 // of ConfluenceBlock. 2856 std::reverse(ConfluenceBlock->pred_begin(), 2857 ConfluenceBlock->pred_end()); 2858 2859 // See if this is a known constant. 2860 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2861 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2862 KnownVal.negate(); 2863 2864 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2865 // itself. 2866 if (E->getOpcode() == BO_LOr) { 2867 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2868 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2869 } else { 2870 assert (E->getOpcode() == BO_LAnd); 2871 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2872 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2873 } 2874 2875 Block = LHSBlock; 2876 return LHSBlock; 2877 } 2878 2879 Block = ConfluenceBlock; 2880 return ConfluenceBlock; 2881 } 2882 2883 if (E->isAssignmentOp()) { 2884 // For assignment operator (=) LHS expression is visited 2885 // before RHS expression. For destructors visit them in reverse order. 2886 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2887 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2888 return LHSBlock ? LHSBlock : RHSBlock; 2889 } 2890 2891 // For any other binary operator RHS expression is visited before 2892 // LHS expression (order of children). For destructors visit them in reverse 2893 // order. 2894 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2895 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2896 return RHSBlock ? RHSBlock : LHSBlock; 2897} 2898 2899CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2900 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2901 // First add destructors for temporaries in subexpression. 2902 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2903 if (!BindToTemporary) { 2904 // If lifetime of temporary is not prolonged (by assigning to constant 2905 // reference) add destructor for it. 2906 2907 // If the destructor is marked as a no-return destructor, we need to create 2908 // a new block for the destructor which does not have as a successor 2909 // anything built thus far. Control won't flow out of this block. 2910 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 2911 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 2912 Block = createNoReturnBlock(); 2913 else 2914 autoCreateBlock(); 2915 2916 appendTemporaryDtor(Block, E); 2917 B = Block; 2918 } 2919 return B; 2920} 2921 2922CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2923 AbstractConditionalOperator *E, bool BindToTemporary) { 2924 // First add destructors for condition expression. Even if this will 2925 // unnecessarily create a block, this block will be used at least by the full 2926 // expression. 2927 autoCreateBlock(); 2928 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2929 if (badCFG) 2930 return NULL; 2931 if (BinaryConditionalOperator *BCO 2932 = dyn_cast<BinaryConditionalOperator>(E)) { 2933 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2934 if (badCFG) 2935 return NULL; 2936 } 2937 2938 // Try to add block with destructors for LHS expression. 2939 CFGBlock *LHSBlock = NULL; 2940 Succ = ConfluenceBlock; 2941 Block = NULL; 2942 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2943 if (badCFG) 2944 return NULL; 2945 2946 // Try to add block with destructors for RHS expression; 2947 Succ = ConfluenceBlock; 2948 Block = NULL; 2949 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2950 BindToTemporary); 2951 if (badCFG) 2952 return NULL; 2953 2954 if (!RHSBlock && !LHSBlock) { 2955 // If neither LHS nor RHS expression had temporaries to destroy don't create 2956 // more blocks. 2957 Block = ConfluenceBlock; 2958 return Block; 2959 } 2960 2961 Block = createBlock(false); 2962 Block->setTerminator(CFGTerminator(E, true)); 2963 2964 // See if this is a known constant. 2965 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2966 2967 if (LHSBlock) { 2968 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2969 } else if (KnownVal.isFalse()) { 2970 addSuccessor(Block, NULL); 2971 } else { 2972 addSuccessor(Block, ConfluenceBlock); 2973 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2974 } 2975 2976 if (!RHSBlock) 2977 RHSBlock = ConfluenceBlock; 2978 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2979 2980 return Block; 2981} 2982 2983} // end anonymous namespace 2984 2985/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2986/// no successors or predecessors. If this is the first block created in the 2987/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2988CFGBlock *CFG::createBlock() { 2989 bool first_block = begin() == end(); 2990 2991 // Create the block. 2992 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2993 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2994 Blocks.push_back(Mem, BlkBVC); 2995 2996 // If this is the first block, set it as the Entry and Exit. 2997 if (first_block) 2998 Entry = Exit = &back(); 2999 3000 // Return the block. 3001 return &back(); 3002} 3003 3004/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 3005/// CFG is returned to the caller. 3006CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 3007 const BuildOptions &BO) { 3008 CFGBuilder Builder(C, BO); 3009 return Builder.buildCFG(D, Statement); 3010} 3011 3012const CXXDestructorDecl * 3013CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 3014 switch (getKind()) { 3015 case CFGElement::Invalid: 3016 case CFGElement::Statement: 3017 case CFGElement::Initializer: 3018 llvm_unreachable("getDestructorDecl should only be used with " 3019 "ImplicitDtors"); 3020 case CFGElement::AutomaticObjectDtor: { 3021 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 3022 QualType ty = var->getType(); 3023 ty = ty.getNonReferenceType(); 3024 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3025 ty = arrayType->getElementType(); 3026 } 3027 const RecordType *recordType = ty->getAs<RecordType>(); 3028 const CXXRecordDecl *classDecl = 3029 cast<CXXRecordDecl>(recordType->getDecl()); 3030 return classDecl->getDestructor(); 3031 } 3032 case CFGElement::TemporaryDtor: { 3033 const CXXBindTemporaryExpr *bindExpr = 3034 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 3035 const CXXTemporary *temp = bindExpr->getTemporary(); 3036 return temp->getDestructor(); 3037 } 3038 case CFGElement::BaseDtor: 3039 case CFGElement::MemberDtor: 3040 3041 // Not yet supported. 3042 return 0; 3043 } 3044 llvm_unreachable("getKind() returned bogus value"); 3045 return 0; 3046} 3047 3048bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3049 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 3050 QualType ty = cdecl->getType(); 3051 return cast<FunctionType>(ty)->getNoReturnAttr(); 3052 } 3053 return false; 3054} 3055 3056//===----------------------------------------------------------------------===// 3057// CFG: Queries for BlkExprs. 3058//===----------------------------------------------------------------------===// 3059 3060namespace { 3061 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3062} 3063 3064static void FindSubExprAssignments(const Stmt *S, 3065 llvm::SmallPtrSet<const Expr*,50>& Set) { 3066 if (!S) 3067 return; 3068 3069 for (Stmt::const_child_range I = S->children(); I; ++I) { 3070 const Stmt *child = *I; 3071 if (!child) 3072 continue; 3073 3074 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3075 if (B->isAssignmentOp()) Set.insert(B); 3076 3077 FindSubExprAssignments(child, Set); 3078 } 3079} 3080 3081static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3082 BlkExprMapTy* M = new BlkExprMapTy(); 3083 3084 // Look for assignments that are used as subexpressions. These are the only 3085 // assignments that we want to *possibly* register as a block-level 3086 // expression. Basically, if an assignment occurs both in a subexpression and 3087 // at the block-level, it is a block-level expression. 3088 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3089 3090 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3091 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3092 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3093 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3094 3095 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3096 3097 // Iterate over the statements again on identify the Expr* and Stmt* at the 3098 // block-level that are block-level expressions. 3099 3100 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3101 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3102 if (!CS) 3103 continue; 3104 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3105 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3106 3107 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3108 // Assignment expressions that are not nested within another 3109 // expression are really "statements" whose value is never used by 3110 // another expression. 3111 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3112 continue; 3113 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3114 // Special handling for statement expressions. The last statement in 3115 // the statement expression is also a block-level expr. 3116 const CompoundStmt *C = SE->getSubStmt(); 3117 if (!C->body_empty()) { 3118 const Stmt *Last = C->body_back(); 3119 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3120 Last = LastEx->IgnoreParens(); 3121 unsigned x = M->size(); 3122 (*M)[Last] = x; 3123 } 3124 } 3125 3126 unsigned x = M->size(); 3127 (*M)[Exp] = x; 3128 } 3129 } 3130 3131 // Look at terminators. The condition is a block-level expression. 3132 3133 Stmt *S = (*I)->getTerminatorCondition(); 3134 3135 if (S && M->find(S) == M->end()) { 3136 unsigned x = M->size(); 3137 (*M)[S] = x; 3138 } 3139 } 3140 3141 return M; 3142} 3143 3144CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3145 assert(S != NULL); 3146 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3147 3148 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3149 BlkExprMapTy::iterator I = M->find(S); 3150 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3151} 3152 3153unsigned CFG::getNumBlkExprs() { 3154 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3155 return M->size(); 3156 3157 // We assume callers interested in the number of BlkExprs will want 3158 // the map constructed if it doesn't already exist. 3159 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3160 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3161} 3162 3163//===----------------------------------------------------------------------===// 3164// Filtered walking of the CFG. 3165//===----------------------------------------------------------------------===// 3166 3167bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3168 const CFGBlock *From, const CFGBlock *To) { 3169 3170 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3171 // If the 'To' has no label or is labeled but the label isn't a 3172 // CaseStmt then filter this edge. 3173 if (const SwitchStmt *S = 3174 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3175 if (S->isAllEnumCasesCovered()) { 3176 const Stmt *L = To->getLabel(); 3177 if (!L || !isa<CaseStmt>(L)) 3178 return true; 3179 } 3180 } 3181 } 3182 3183 return false; 3184} 3185 3186//===----------------------------------------------------------------------===// 3187// Cleanup: CFG dstor. 3188//===----------------------------------------------------------------------===// 3189 3190CFG::~CFG() { 3191 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3192} 3193 3194//===----------------------------------------------------------------------===// 3195// CFG pretty printing 3196//===----------------------------------------------------------------------===// 3197 3198namespace { 3199 3200class StmtPrinterHelper : public PrinterHelper { 3201 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3202 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3203 StmtMapTy StmtMap; 3204 DeclMapTy DeclMap; 3205 signed currentBlock; 3206 unsigned currentStmt; 3207 const LangOptions &LangOpts; 3208public: 3209 3210 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3211 : currentBlock(0), currentStmt(0), LangOpts(LO) 3212 { 3213 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3214 unsigned j = 1; 3215 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3216 BI != BEnd; ++BI, ++j ) { 3217 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3218 const Stmt *stmt= SE->getStmt(); 3219 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3220 StmtMap[stmt] = P; 3221 3222 switch (stmt->getStmtClass()) { 3223 case Stmt::DeclStmtClass: 3224 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3225 break; 3226 case Stmt::IfStmtClass: { 3227 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3228 if (var) 3229 DeclMap[var] = P; 3230 break; 3231 } 3232 case Stmt::ForStmtClass: { 3233 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3234 if (var) 3235 DeclMap[var] = P; 3236 break; 3237 } 3238 case Stmt::WhileStmtClass: { 3239 const VarDecl *var = 3240 cast<WhileStmt>(stmt)->getConditionVariable(); 3241 if (var) 3242 DeclMap[var] = P; 3243 break; 3244 } 3245 case Stmt::SwitchStmtClass: { 3246 const VarDecl *var = 3247 cast<SwitchStmt>(stmt)->getConditionVariable(); 3248 if (var) 3249 DeclMap[var] = P; 3250 break; 3251 } 3252 case Stmt::CXXCatchStmtClass: { 3253 const VarDecl *var = 3254 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3255 if (var) 3256 DeclMap[var] = P; 3257 break; 3258 } 3259 default: 3260 break; 3261 } 3262 } 3263 } 3264 } 3265 } 3266 3267 3268 virtual ~StmtPrinterHelper() {} 3269 3270 const LangOptions &getLangOpts() const { return LangOpts; } 3271 void setBlockID(signed i) { currentBlock = i; } 3272 void setStmtID(unsigned i) { currentStmt = i; } 3273 3274 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3275 StmtMapTy::iterator I = StmtMap.find(S); 3276 3277 if (I == StmtMap.end()) 3278 return false; 3279 3280 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3281 && I->second.second == currentStmt) { 3282 return false; 3283 } 3284 3285 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3286 return true; 3287 } 3288 3289 bool handleDecl(const Decl *D, raw_ostream &OS) { 3290 DeclMapTy::iterator I = DeclMap.find(D); 3291 3292 if (I == DeclMap.end()) 3293 return false; 3294 3295 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3296 && I->second.second == currentStmt) { 3297 return false; 3298 } 3299 3300 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3301 return true; 3302 } 3303}; 3304} // end anonymous namespace 3305 3306 3307namespace { 3308class CFGBlockTerminatorPrint 3309 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3310 3311 raw_ostream &OS; 3312 StmtPrinterHelper* Helper; 3313 PrintingPolicy Policy; 3314public: 3315 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3316 const PrintingPolicy &Policy) 3317 : OS(os), Helper(helper), Policy(Policy) {} 3318 3319 void VisitIfStmt(IfStmt *I) { 3320 OS << "if "; 3321 I->getCond()->printPretty(OS,Helper,Policy); 3322 } 3323 3324 // Default case. 3325 void VisitStmt(Stmt *Terminator) { 3326 Terminator->printPretty(OS, Helper, Policy); 3327 } 3328 3329 void VisitForStmt(ForStmt *F) { 3330 OS << "for (" ; 3331 if (F->getInit()) 3332 OS << "..."; 3333 OS << "; "; 3334 if (Stmt *C = F->getCond()) 3335 C->printPretty(OS, Helper, Policy); 3336 OS << "; "; 3337 if (F->getInc()) 3338 OS << "..."; 3339 OS << ")"; 3340 } 3341 3342 void VisitWhileStmt(WhileStmt *W) { 3343 OS << "while " ; 3344 if (Stmt *C = W->getCond()) 3345 C->printPretty(OS, Helper, Policy); 3346 } 3347 3348 void VisitDoStmt(DoStmt *D) { 3349 OS << "do ... while "; 3350 if (Stmt *C = D->getCond()) 3351 C->printPretty(OS, Helper, Policy); 3352 } 3353 3354 void VisitSwitchStmt(SwitchStmt *Terminator) { 3355 OS << "switch "; 3356 Terminator->getCond()->printPretty(OS, Helper, Policy); 3357 } 3358 3359 void VisitCXXTryStmt(CXXTryStmt *CS) { 3360 OS << "try ..."; 3361 } 3362 3363 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3364 C->getCond()->printPretty(OS, Helper, Policy); 3365 OS << " ? ... : ..."; 3366 } 3367 3368 void VisitChooseExpr(ChooseExpr *C) { 3369 OS << "__builtin_choose_expr( "; 3370 C->getCond()->printPretty(OS, Helper, Policy); 3371 OS << " )"; 3372 } 3373 3374 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3375 OS << "goto *"; 3376 I->getTarget()->printPretty(OS, Helper, Policy); 3377 } 3378 3379 void VisitBinaryOperator(BinaryOperator* B) { 3380 if (!B->isLogicalOp()) { 3381 VisitExpr(B); 3382 return; 3383 } 3384 3385 B->getLHS()->printPretty(OS, Helper, Policy); 3386 3387 switch (B->getOpcode()) { 3388 case BO_LOr: 3389 OS << " || ..."; 3390 return; 3391 case BO_LAnd: 3392 OS << " && ..."; 3393 return; 3394 default: 3395 llvm_unreachable("Invalid logical operator."); 3396 } 3397 } 3398 3399 void VisitExpr(Expr *E) { 3400 E->printPretty(OS, Helper, Policy); 3401 } 3402}; 3403} // end anonymous namespace 3404 3405static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3406 const CFGElement &E) { 3407 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3408 const Stmt *S = CS->getStmt(); 3409 3410 if (Helper) { 3411 3412 // special printing for statement-expressions. 3413 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3414 const CompoundStmt *Sub = SE->getSubStmt(); 3415 3416 if (Sub->children()) { 3417 OS << "({ ... ; "; 3418 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3419 OS << " })\n"; 3420 return; 3421 } 3422 } 3423 // special printing for comma expressions. 3424 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3425 if (B->getOpcode() == BO_Comma) { 3426 OS << "... , "; 3427 Helper->handledStmt(B->getRHS(),OS); 3428 OS << '\n'; 3429 return; 3430 } 3431 } 3432 } 3433 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3434 3435 if (isa<CXXOperatorCallExpr>(S)) { 3436 OS << " (OperatorCall)"; 3437 } else if (isa<CXXBindTemporaryExpr>(S)) { 3438 OS << " (BindTemporary)"; 3439 } 3440 3441 // Expressions need a newline. 3442 if (isa<Expr>(S)) 3443 OS << '\n'; 3444 3445 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3446 const CXXCtorInitializer *I = IE->getInitializer(); 3447 if (I->isBaseInitializer()) 3448 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3449 else OS << I->getAnyMember()->getName(); 3450 3451 OS << "("; 3452 if (Expr *IE = I->getInit()) 3453 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3454 OS << ")"; 3455 3456 if (I->isBaseInitializer()) 3457 OS << " (Base initializer)\n"; 3458 else OS << " (Member initializer)\n"; 3459 3460 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3461 const VarDecl *VD = DE->getVarDecl(); 3462 Helper->handleDecl(VD, OS); 3463 3464 const Type* T = VD->getType().getTypePtr(); 3465 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3466 T = RT->getPointeeType().getTypePtr(); 3467 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3468 T = ET; 3469 3470 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3471 OS << " (Implicit destructor)\n"; 3472 3473 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3474 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3475 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3476 OS << " (Base object destructor)\n"; 3477 3478 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3479 const FieldDecl *FD = ME->getFieldDecl(); 3480 3481 const Type *T = FD->getType().getTypePtr(); 3482 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3483 T = ET; 3484 3485 OS << "this->" << FD->getName(); 3486 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3487 OS << " (Member object destructor)\n"; 3488 3489 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3490 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3491 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3492 OS << " (Temporary object destructor)\n"; 3493 } 3494} 3495 3496static void print_block(raw_ostream &OS, const CFG* cfg, 3497 const CFGBlock &B, 3498 StmtPrinterHelper* Helper, bool print_edges) { 3499 3500 if (Helper) Helper->setBlockID(B.getBlockID()); 3501 3502 // Print the header. 3503 OS << "\n [ B" << B.getBlockID(); 3504 3505 if (&B == &cfg->getEntry()) 3506 OS << " (ENTRY) ]\n"; 3507 else if (&B == &cfg->getExit()) 3508 OS << " (EXIT) ]\n"; 3509 else if (&B == cfg->getIndirectGotoBlock()) 3510 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3511 else 3512 OS << " ]\n"; 3513 3514 // Print the label of this block. 3515 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3516 3517 if (print_edges) 3518 OS << " "; 3519 3520 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3521 OS << L->getName(); 3522 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3523 OS << "case "; 3524 C->getLHS()->printPretty(OS, Helper, 3525 PrintingPolicy(Helper->getLangOpts())); 3526 if (C->getRHS()) { 3527 OS << " ... "; 3528 C->getRHS()->printPretty(OS, Helper, 3529 PrintingPolicy(Helper->getLangOpts())); 3530 } 3531 } else if (isa<DefaultStmt>(Label)) 3532 OS << "default"; 3533 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3534 OS << "catch ("; 3535 if (CS->getExceptionDecl()) 3536 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3537 0); 3538 else 3539 OS << "..."; 3540 OS << ")"; 3541 3542 } else 3543 llvm_unreachable("Invalid label statement in CFGBlock."); 3544 3545 OS << ":\n"; 3546 } 3547 3548 // Iterate through the statements in the block and print them. 3549 unsigned j = 1; 3550 3551 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3552 I != E ; ++I, ++j ) { 3553 3554 // Print the statement # in the basic block and the statement itself. 3555 if (print_edges) 3556 OS << " "; 3557 3558 OS << llvm::format("%3d", j) << ": "; 3559 3560 if (Helper) 3561 Helper->setStmtID(j); 3562 3563 print_elem(OS,Helper,*I); 3564 } 3565 3566 // Print the terminator of this block. 3567 if (B.getTerminator()) { 3568 if (print_edges) 3569 OS << " "; 3570 3571 OS << " T: "; 3572 3573 if (Helper) Helper->setBlockID(-1); 3574 3575 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3576 PrintingPolicy(Helper->getLangOpts())); 3577 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3578 OS << '\n'; 3579 } 3580 3581 if (print_edges) { 3582 // Print the predecessors of this block. 3583 OS << " Predecessors (" << B.pred_size() << "):"; 3584 unsigned i = 0; 3585 3586 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3587 I != E; ++I, ++i) { 3588 3589 if (i == 8 || (i-8) == 0) 3590 OS << "\n "; 3591 3592 OS << " B" << (*I)->getBlockID(); 3593 } 3594 3595 OS << '\n'; 3596 3597 // Print the successors of this block. 3598 OS << " Successors (" << B.succ_size() << "):"; 3599 i = 0; 3600 3601 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3602 I != E; ++I, ++i) { 3603 3604 if (i == 8 || (i-8) % 10 == 0) 3605 OS << "\n "; 3606 3607 if (*I) 3608 OS << " B" << (*I)->getBlockID(); 3609 else 3610 OS << " NULL"; 3611 } 3612 3613 OS << '\n'; 3614 } 3615} 3616 3617 3618/// dump - A simple pretty printer of a CFG that outputs to stderr. 3619void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3620 3621/// print - A simple pretty printer of a CFG that outputs to an ostream. 3622void CFG::print(raw_ostream &OS, const LangOptions &LO) const { 3623 StmtPrinterHelper Helper(this, LO); 3624 3625 // Print the entry block. 3626 print_block(OS, this, getEntry(), &Helper, true); 3627 3628 // Iterate through the CFGBlocks and print them one by one. 3629 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3630 // Skip the entry block, because we already printed it. 3631 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3632 continue; 3633 3634 print_block(OS, this, **I, &Helper, true); 3635 } 3636 3637 // Print the exit block. 3638 print_block(OS, this, getExit(), &Helper, true); 3639 OS.flush(); 3640} 3641 3642/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3643void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3644 print(llvm::errs(), cfg, LO); 3645} 3646 3647/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3648/// Generally this will only be called from CFG::print. 3649void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3650 const LangOptions &LO) const { 3651 StmtPrinterHelper Helper(cfg, LO); 3652 print_block(OS, cfg, *this, &Helper, true); 3653} 3654 3655/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3656void CFGBlock::printTerminator(raw_ostream &OS, 3657 const LangOptions &LO) const { 3658 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3659 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3660} 3661 3662Stmt *CFGBlock::getTerminatorCondition() { 3663 Stmt *Terminator = this->Terminator; 3664 if (!Terminator) 3665 return NULL; 3666 3667 Expr *E = NULL; 3668 3669 switch (Terminator->getStmtClass()) { 3670 default: 3671 break; 3672 3673 case Stmt::ForStmtClass: 3674 E = cast<ForStmt>(Terminator)->getCond(); 3675 break; 3676 3677 case Stmt::WhileStmtClass: 3678 E = cast<WhileStmt>(Terminator)->getCond(); 3679 break; 3680 3681 case Stmt::DoStmtClass: 3682 E = cast<DoStmt>(Terminator)->getCond(); 3683 break; 3684 3685 case Stmt::IfStmtClass: 3686 E = cast<IfStmt>(Terminator)->getCond(); 3687 break; 3688 3689 case Stmt::ChooseExprClass: 3690 E = cast<ChooseExpr>(Terminator)->getCond(); 3691 break; 3692 3693 case Stmt::IndirectGotoStmtClass: 3694 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3695 break; 3696 3697 case Stmt::SwitchStmtClass: 3698 E = cast<SwitchStmt>(Terminator)->getCond(); 3699 break; 3700 3701 case Stmt::BinaryConditionalOperatorClass: 3702 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3703 break; 3704 3705 case Stmt::ConditionalOperatorClass: 3706 E = cast<ConditionalOperator>(Terminator)->getCond(); 3707 break; 3708 3709 case Stmt::BinaryOperatorClass: // '&&' and '||' 3710 E = cast<BinaryOperator>(Terminator)->getLHS(); 3711 break; 3712 3713 case Stmt::ObjCForCollectionStmtClass: 3714 return Terminator; 3715 } 3716 3717 return E ? E->IgnoreParens() : NULL; 3718} 3719 3720//===----------------------------------------------------------------------===// 3721// CFG Graphviz Visualization 3722//===----------------------------------------------------------------------===// 3723 3724 3725#ifndef NDEBUG 3726static StmtPrinterHelper* GraphHelper; 3727#endif 3728 3729void CFG::viewCFG(const LangOptions &LO) const { 3730#ifndef NDEBUG 3731 StmtPrinterHelper H(this, LO); 3732 GraphHelper = &H; 3733 llvm::ViewGraph(this,"CFG"); 3734 GraphHelper = NULL; 3735#endif 3736} 3737 3738namespace llvm { 3739template<> 3740struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3741 3742 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3743 3744 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 3745 3746#ifndef NDEBUG 3747 std::string OutSStr; 3748 llvm::raw_string_ostream Out(OutSStr); 3749 print_block(Out,Graph, *Node, GraphHelper, false); 3750 std::string& OutStr = Out.str(); 3751 3752 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3753 3754 // Process string output to make it nicer... 3755 for (unsigned i = 0; i != OutStr.length(); ++i) 3756 if (OutStr[i] == '\n') { // Left justify 3757 OutStr[i] = '\\'; 3758 OutStr.insert(OutStr.begin()+i+1, 'l'); 3759 } 3760 3761 return OutStr; 3762#else 3763 return ""; 3764#endif 3765 } 3766}; 3767} // end namespace llvm 3768