CFG.cpp revision dba3fb5413437dc613734fa4ffac892b11a37d25
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "clang/AST/CharUnits.h" 21#include "llvm/Support/GraphWriter.h" 22#include "llvm/Support/Allocator.h" 23#include "llvm/Support/Format.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/OwningPtr.h" 27 28using namespace clang; 29 30namespace { 31 32static SourceLocation GetEndLoc(Decl *D) { 33 if (VarDecl *VD = dyn_cast<VarDecl>(D)) 34 if (Expr *Ex = VD->getInit()) 35 return Ex->getSourceRange().getEnd(); 36 return D->getLocation(); 37} 38 39class CFGBuilder; 40 41/// The CFG builder uses a recursive algorithm to build the CFG. When 42/// we process an expression, sometimes we know that we must add the 43/// subexpressions as block-level expressions. For example: 44/// 45/// exp1 || exp2 46/// 47/// When processing the '||' expression, we know that exp1 and exp2 48/// need to be added as block-level expressions, even though they 49/// might not normally need to be. AddStmtChoice records this 50/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 51/// the builder has an option not to add a subexpression as a 52/// block-level expression. 53/// 54class AddStmtChoice { 55public: 56 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 57 58 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 59 60 bool alwaysAdd(CFGBuilder &builder, 61 const Stmt *stmt) const; 62 63 /// Return a copy of this object, except with the 'always-add' bit 64 /// set as specified. 65 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 66 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 67 } 68 69private: 70 Kind kind; 71}; 72 73/// LocalScope - Node in tree of local scopes created for C++ implicit 74/// destructor calls generation. It contains list of automatic variables 75/// declared in the scope and link to position in previous scope this scope 76/// began in. 77/// 78/// The process of creating local scopes is as follows: 79/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 80/// - Before processing statements in scope (e.g. CompoundStmt) create 81/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 82/// and set CFGBuilder::ScopePos to the end of new scope, 83/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 84/// at this VarDecl, 85/// - For every normal (without jump) end of scope add to CFGBlock destructors 86/// for objects in the current scope, 87/// - For every jump add to CFGBlock destructors for objects 88/// between CFGBuilder::ScopePos and local scope position saved for jump 89/// target. Thanks to C++ restrictions on goto jumps we can be sure that 90/// jump target position will be on the path to root from CFGBuilder::ScopePos 91/// (adding any variable that doesn't need constructor to be called to 92/// LocalScope can break this assumption), 93/// 94class LocalScope { 95public: 96 typedef BumpVector<VarDecl*> AutomaticVarsTy; 97 98 /// const_iterator - Iterates local scope backwards and jumps to previous 99 /// scope on reaching the beginning of currently iterated scope. 100 class const_iterator { 101 const LocalScope* Scope; 102 103 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 104 /// Invalid iterator (with null Scope) has VarIter equal to 0. 105 unsigned VarIter; 106 107 public: 108 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 109 /// Incrementing invalid iterator is allowed and will result in invalid 110 /// iterator. 111 const_iterator() 112 : Scope(NULL), VarIter(0) {} 113 114 /// Create valid iterator. In case when S.Prev is an invalid iterator and 115 /// I is equal to 0, this will create invalid iterator. 116 const_iterator(const LocalScope& S, unsigned I) 117 : Scope(&S), VarIter(I) { 118 // Iterator to "end" of scope is not allowed. Handle it by going up 119 // in scopes tree possibly up to invalid iterator in the root. 120 if (VarIter == 0 && Scope) 121 *this = Scope->Prev; 122 } 123 124 VarDecl *const* operator->() const { 125 assert (Scope && "Dereferencing invalid iterator is not allowed"); 126 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 127 return &Scope->Vars[VarIter - 1]; 128 } 129 VarDecl *operator*() const { 130 return *this->operator->(); 131 } 132 133 const_iterator &operator++() { 134 if (!Scope) 135 return *this; 136 137 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 138 --VarIter; 139 if (VarIter == 0) 140 *this = Scope->Prev; 141 return *this; 142 } 143 const_iterator operator++(int) { 144 const_iterator P = *this; 145 ++*this; 146 return P; 147 } 148 149 bool operator==(const const_iterator &rhs) const { 150 return Scope == rhs.Scope && VarIter == rhs.VarIter; 151 } 152 bool operator!=(const const_iterator &rhs) const { 153 return !(*this == rhs); 154 } 155 156 operator bool() const { 157 return *this != const_iterator(); 158 } 159 160 int distance(const_iterator L); 161 }; 162 163 friend class const_iterator; 164 165private: 166 BumpVectorContext ctx; 167 168 /// Automatic variables in order of declaration. 169 AutomaticVarsTy Vars; 170 /// Iterator to variable in previous scope that was declared just before 171 /// begin of this scope. 172 const_iterator Prev; 173 174public: 175 /// Constructs empty scope linked to previous scope in specified place. 176 LocalScope(BumpVectorContext &ctx, const_iterator P) 177 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 178 179 /// Begin of scope in direction of CFG building (backwards). 180 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 181 182 void addVar(VarDecl *VD) { 183 Vars.push_back(VD, ctx); 184 } 185}; 186 187/// distance - Calculates distance from this to L. L must be reachable from this 188/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 189/// number of scopes between this and L. 190int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 191 int D = 0; 192 const_iterator F = *this; 193 while (F.Scope != L.Scope) { 194 assert (F != const_iterator() 195 && "L iterator is not reachable from F iterator."); 196 D += F.VarIter; 197 F = F.Scope->Prev; 198 } 199 D += F.VarIter - L.VarIter; 200 return D; 201} 202 203/// BlockScopePosPair - Structure for specifying position in CFG during its 204/// build process. It consists of CFGBlock that specifies position in CFG graph 205/// and LocalScope::const_iterator that specifies position in LocalScope graph. 206struct BlockScopePosPair { 207 BlockScopePosPair() : block(0) {} 208 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos) 209 : block(b), scopePosition(scopePos) {} 210 211 CFGBlock *block; 212 LocalScope::const_iterator scopePosition; 213}; 214 215/// TryResult - a class representing a variant over the values 216/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 217/// and is used by the CFGBuilder to decide if a branch condition 218/// can be decided up front during CFG construction. 219class TryResult { 220 int X; 221public: 222 TryResult(bool b) : X(b ? 1 : 0) {} 223 TryResult() : X(-1) {} 224 225 bool isTrue() const { return X == 1; } 226 bool isFalse() const { return X == 0; } 227 bool isKnown() const { return X >= 0; } 228 void negate() { 229 assert(isKnown()); 230 X ^= 0x1; 231 } 232}; 233 234/// CFGBuilder - This class implements CFG construction from an AST. 235/// The builder is stateful: an instance of the builder should be used to only 236/// construct a single CFG. 237/// 238/// Example usage: 239/// 240/// CFGBuilder builder; 241/// CFG* cfg = builder.BuildAST(stmt1); 242/// 243/// CFG construction is done via a recursive walk of an AST. We actually parse 244/// the AST in reverse order so that the successor of a basic block is 245/// constructed prior to its predecessor. This allows us to nicely capture 246/// implicit fall-throughs without extra basic blocks. 247/// 248class CFGBuilder { 249 typedef BlockScopePosPair JumpTarget; 250 typedef BlockScopePosPair JumpSource; 251 252 ASTContext *Context; 253 llvm::OwningPtr<CFG> cfg; 254 255 CFGBlock *Block; 256 CFGBlock *Succ; 257 JumpTarget ContinueJumpTarget; 258 JumpTarget BreakJumpTarget; 259 CFGBlock *SwitchTerminatedBlock; 260 CFGBlock *DefaultCaseBlock; 261 CFGBlock *TryTerminatedBlock; 262 263 // Current position in local scope. 264 LocalScope::const_iterator ScopePos; 265 266 // LabelMap records the mapping from Label expressions to their jump targets. 267 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 268 LabelMapTy LabelMap; 269 270 // A list of blocks that end with a "goto" that must be backpatched to their 271 // resolved targets upon completion of CFG construction. 272 typedef std::vector<JumpSource> BackpatchBlocksTy; 273 BackpatchBlocksTy BackpatchBlocks; 274 275 // A list of labels whose address has been taken (for indirect gotos). 276 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 277 LabelSetTy AddressTakenLabels; 278 279 bool badCFG; 280 const CFG::BuildOptions &BuildOpts; 281 282 // State to track for building switch statements. 283 bool switchExclusivelyCovered; 284 Expr::EvalResult *switchCond; 285 286 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 287 const Stmt *lastLookup; 288 289public: 290 explicit CFGBuilder(ASTContext *astContext, 291 const CFG::BuildOptions &buildOpts) 292 : Context(astContext), cfg(new CFG()), // crew a new CFG 293 Block(NULL), Succ(NULL), 294 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 295 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 296 switchExclusivelyCovered(false), switchCond(0), 297 cachedEntry(0), lastLookup(0) {} 298 299 // buildCFG - Used by external clients to construct the CFG. 300 CFG* buildCFG(const Decl *D, Stmt *Statement); 301 302 bool alwaysAdd(const Stmt *stmt); 303 304private: 305 // Visitors to walk an AST and construct the CFG. 306 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 307 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 308 CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc); 309 CFGBlock *VisitBreakStmt(BreakStmt *B); 310 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 311 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 312 AddStmtChoice asc); 313 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 314 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 315 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 316 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 317 AddStmtChoice asc); 318 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 319 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 320 AddStmtChoice asc); 321 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 322 AddStmtChoice asc); 323 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 324 CFGBlock *VisitCaseStmt(CaseStmt *C); 325 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 326 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 327 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 328 AddStmtChoice asc); 329 CFGBlock *VisitContinueStmt(ContinueStmt *C); 330 CFGBlock *VisitDeclStmt(DeclStmt *DS); 331 CFGBlock *VisitDeclSubExpr(DeclStmt *DS); 332 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 333 CFGBlock *VisitDoStmt(DoStmt *D); 334 CFGBlock *VisitForStmt(ForStmt *F); 335 CFGBlock *VisitGotoStmt(GotoStmt *G); 336 CFGBlock *VisitIfStmt(IfStmt *I); 337 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 338 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 339 CFGBlock *VisitLabelStmt(LabelStmt *L); 340 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 341 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 342 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 343 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 344 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 345 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 346 CFGBlock *VisitReturnStmt(ReturnStmt *R); 347 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 348 AddStmtChoice asc); 349 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 350 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 351 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 352 CFGBlock *VisitWhileStmt(WhileStmt *W); 353 354 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 355 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 356 CFGBlock *VisitChildren(Stmt *S); 357 358 // Visitors to walk an AST and generate destructors of temporaries in 359 // full expression. 360 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 361 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 362 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 363 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 364 bool BindToTemporary); 365 CFGBlock * 366 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 367 bool BindToTemporary); 368 369 // NYS == Not Yet Supported 370 CFGBlock *NYS() { 371 badCFG = true; 372 return Block; 373 } 374 375 void autoCreateBlock() { if (!Block) Block = createBlock(); } 376 CFGBlock *createBlock(bool add_successor = true); 377 CFGBlock *createNoReturnBlock(); 378 379 CFGBlock *addStmt(Stmt *S) { 380 return Visit(S, AddStmtChoice::AlwaysAdd); 381 } 382 CFGBlock *addInitializer(CXXCtorInitializer *I); 383 void addAutomaticObjDtors(LocalScope::const_iterator B, 384 LocalScope::const_iterator E, Stmt *S); 385 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 386 387 // Local scopes creation. 388 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 389 390 void addLocalScopeForStmt(Stmt *S); 391 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 392 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 393 394 void addLocalScopeAndDtors(Stmt *S); 395 396 // Interface to CFGBlock - adding CFGElements. 397 void appendStmt(CFGBlock *B, const Stmt *S) { 398 if (alwaysAdd(S) && cachedEntry) 399 cachedEntry->second = B; 400 401 // All block-level expressions should have already been IgnoreParens()ed. 402 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 403 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 404 } 405 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 406 B->appendInitializer(I, cfg->getBumpVectorContext()); 407 } 408 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 409 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 410 } 411 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 412 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 413 } 414 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 415 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 416 } 417 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 418 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 419 } 420 421 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 422 LocalScope::const_iterator B, LocalScope::const_iterator E); 423 424 void addSuccessor(CFGBlock *B, CFGBlock *S) { 425 B->addSuccessor(S, cfg->getBumpVectorContext()); 426 } 427 428 /// Try and evaluate an expression to an integer constant. 429 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 430 if (!BuildOpts.PruneTriviallyFalseEdges) 431 return false; 432 return !S->isTypeDependent() && 433 !S->isValueDependent() && 434 S->Evaluate(outResult, *Context); 435 } 436 437 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 438 /// if we can evaluate to a known value, otherwise return -1. 439 TryResult tryEvaluateBool(Expr *S) { 440 Expr::EvalResult Result; 441 if (!tryEvaluate(S, Result)) 442 return TryResult(); 443 444 if (Result.Val.isInt()) 445 return Result.Val.getInt().getBoolValue(); 446 447 if (Result.Val.isLValue()) { 448 const Expr *e = Result.Val.getLValueBase(); 449 const CharUnits &c = Result.Val.getLValueOffset(); 450 if (!e && c.isZero()) 451 return false; 452 } 453 return TryResult(); 454 } 455 456}; 457 458inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 459 const Stmt *stmt) const { 460 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 461} 462 463bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 464 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 465 466 if (!BuildOpts.forcedBlkExprs) 467 return shouldAdd; 468 469 if (lastLookup == stmt) { 470 if (cachedEntry) { 471 assert(cachedEntry->first == stmt); 472 return true; 473 } 474 return shouldAdd; 475 } 476 477 lastLookup = stmt; 478 479 // Perform the lookup! 480 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 481 482 if (!fb) { 483 // No need to update 'cachedEntry', since it will always be null. 484 assert(cachedEntry == 0); 485 return shouldAdd; 486 } 487 488 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 489 if (itr == fb->end()) { 490 cachedEntry = 0; 491 return shouldAdd; 492 } 493 494 cachedEntry = &*itr; 495 return true; 496} 497 498// FIXME: Add support for dependent-sized array types in C++? 499// Does it even make sense to build a CFG for an uninstantiated template? 500static const VariableArrayType *FindVA(const Type *t) { 501 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 502 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 503 if (vat->getSizeExpr()) 504 return vat; 505 506 t = vt->getElementType().getTypePtr(); 507 } 508 509 return 0; 510} 511 512/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 513/// arbitrary statement. Examples include a single expression or a function 514/// body (compound statement). The ownership of the returned CFG is 515/// transferred to the caller. If CFG construction fails, this method returns 516/// NULL. 517CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 518 assert(cfg.get()); 519 if (!Statement) 520 return NULL; 521 522 // Create an empty block that will serve as the exit block for the CFG. Since 523 // this is the first block added to the CFG, it will be implicitly registered 524 // as the exit block. 525 Succ = createBlock(); 526 assert(Succ == &cfg->getExit()); 527 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 528 529 if (BuildOpts.AddImplicitDtors) 530 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 531 addImplicitDtorsForDestructor(DD); 532 533 // Visit the statements and create the CFG. 534 CFGBlock *B = addStmt(Statement); 535 536 if (badCFG) 537 return NULL; 538 539 // For C++ constructor add initializers to CFG. 540 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 541 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 542 E = CD->init_rend(); I != E; ++I) { 543 B = addInitializer(*I); 544 if (badCFG) 545 return NULL; 546 } 547 } 548 549 if (B) 550 Succ = B; 551 552 // Backpatch the gotos whose label -> block mappings we didn't know when we 553 // encountered them. 554 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 555 E = BackpatchBlocks.end(); I != E; ++I ) { 556 557 CFGBlock *B = I->block; 558 GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 559 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 560 561 // If there is no target for the goto, then we are looking at an 562 // incomplete AST. Handle this by not registering a successor. 563 if (LI == LabelMap.end()) continue; 564 565 JumpTarget JT = LI->second; 566 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 567 JT.scopePosition); 568 addSuccessor(B, JT.block); 569 } 570 571 // Add successors to the Indirect Goto Dispatch block (if we have one). 572 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 573 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 574 E = AddressTakenLabels.end(); I != E; ++I ) { 575 576 // Lookup the target block. 577 LabelMapTy::iterator LI = LabelMap.find(*I); 578 579 // If there is no target block that contains label, then we are looking 580 // at an incomplete AST. Handle this by not registering a successor. 581 if (LI == LabelMap.end()) continue; 582 583 addSuccessor(B, LI->second.block); 584 } 585 586 // Create an empty entry block that has no predecessors. 587 cfg->setEntry(createBlock()); 588 589 return cfg.take(); 590} 591 592/// createBlock - Used to lazily create blocks that are connected 593/// to the current (global) succcessor. 594CFGBlock *CFGBuilder::createBlock(bool add_successor) { 595 CFGBlock *B = cfg->createBlock(); 596 if (add_successor && Succ) 597 addSuccessor(B, Succ); 598 return B; 599} 600 601/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the 602/// CFG. It is *not* connected to the current (global) successor, and instead 603/// directly tied to the exit block in order to be reachable. 604CFGBlock *CFGBuilder::createNoReturnBlock() { 605 CFGBlock *B = createBlock(false); 606 addSuccessor(B, &cfg->getExit()); 607 return B; 608} 609 610/// addInitializer - Add C++ base or member initializer element to CFG. 611CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 612 if (!BuildOpts.AddInitializers) 613 return Block; 614 615 bool IsReference = false; 616 bool HasTemporaries = false; 617 618 // Destructors of temporaries in initialization expression should be called 619 // after initialization finishes. 620 Expr *Init = I->getInit(); 621 if (Init) { 622 if (FieldDecl *FD = I->getAnyMember()) 623 IsReference = FD->getType()->isReferenceType(); 624 HasTemporaries = isa<ExprWithCleanups>(Init); 625 626 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 627 // Generate destructors for temporaries in initialization expression. 628 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 629 IsReference); 630 } 631 } 632 633 autoCreateBlock(); 634 appendInitializer(Block, I); 635 636 if (Init) { 637 if (HasTemporaries) { 638 // For expression with temporaries go directly to subexpression to omit 639 // generating destructors for the second time. 640 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 641 } 642 return Visit(Init); 643 } 644 645 return Block; 646} 647 648/// addAutomaticObjDtors - Add to current block automatic objects destructors 649/// for objects in range of local scope positions. Use S as trigger statement 650/// for destructors. 651void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 652 LocalScope::const_iterator E, Stmt *S) { 653 if (!BuildOpts.AddImplicitDtors) 654 return; 655 656 if (B == E) 657 return; 658 659 CFGBlock::iterator InsertPos; 660 661 // We need to append the destructors in reverse order, but any one of them 662 // may be a no-return destructor which changes the CFG. As a result, buffer 663 // this sequence up and replay them in reverse order when appending onto the 664 // CFGBlock(s). 665 SmallVector<VarDecl*, 10> Decls; 666 Decls.reserve(B.distance(E)); 667 for (LocalScope::const_iterator I = B; I != E; ++I) 668 Decls.push_back(*I); 669 670 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 671 E = Decls.rend(); 672 I != E; ++I) { 673 // If this destructor is marked as a no-return destructor, we need to 674 // create a new block for the destructor which does not have as a successor 675 // anything built thus far: control won't flow out of this block. 676 QualType Ty = (*I)->getType().getNonReferenceType(); 677 if (const ArrayType *AT = Context->getAsArrayType(Ty)) 678 Ty = AT->getElementType(); 679 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 680 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 681 Block = createNoReturnBlock(); 682 else 683 autoCreateBlock(); 684 685 appendAutomaticObjDtor(Block, *I, S); 686 } 687} 688 689/// addImplicitDtorsForDestructor - Add implicit destructors generated for 690/// base and member objects in destructor. 691void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 692 assert (BuildOpts.AddImplicitDtors 693 && "Can be called only when dtors should be added"); 694 const CXXRecordDecl *RD = DD->getParent(); 695 696 // At the end destroy virtual base objects. 697 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 698 VE = RD->vbases_end(); VI != VE; ++VI) { 699 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 700 if (!CD->hasTrivialDestructor()) { 701 autoCreateBlock(); 702 appendBaseDtor(Block, VI); 703 } 704 } 705 706 // Before virtual bases destroy direct base objects. 707 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 708 BE = RD->bases_end(); BI != BE; ++BI) { 709 if (!BI->isVirtual()) { 710 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 711 if (!CD->hasTrivialDestructor()) { 712 autoCreateBlock(); 713 appendBaseDtor(Block, BI); 714 } 715 } 716 } 717 718 // First destroy member objects. 719 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 720 FE = RD->field_end(); FI != FE; ++FI) { 721 // Check for constant size array. Set type to array element type. 722 QualType QT = FI->getType(); 723 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 724 if (AT->getSize() == 0) 725 continue; 726 QT = AT->getElementType(); 727 } 728 729 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 730 if (!CD->hasTrivialDestructor()) { 731 autoCreateBlock(); 732 appendMemberDtor(Block, *FI); 733 } 734 } 735} 736 737/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 738/// way return valid LocalScope object. 739LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 740 if (!Scope) { 741 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 742 Scope = alloc.Allocate<LocalScope>(); 743 BumpVectorContext ctx(alloc); 744 new (Scope) LocalScope(ctx, ScopePos); 745 } 746 return Scope; 747} 748 749/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 750/// that should create implicit scope (e.g. if/else substatements). 751void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 752 if (!BuildOpts.AddImplicitDtors) 753 return; 754 755 LocalScope *Scope = 0; 756 757 // For compound statement we will be creating explicit scope. 758 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 759 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 760 ; BI != BE; ++BI) { 761 Stmt *SI = (*BI)->stripLabelLikeStatements(); 762 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 763 Scope = addLocalScopeForDeclStmt(DS, Scope); 764 } 765 return; 766 } 767 768 // For any other statement scope will be implicit and as such will be 769 // interesting only for DeclStmt. 770 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 771 addLocalScopeForDeclStmt(DS); 772} 773 774/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 775/// reuse Scope if not NULL. 776LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 777 LocalScope* Scope) { 778 if (!BuildOpts.AddImplicitDtors) 779 return Scope; 780 781 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 782 ; DI != DE; ++DI) { 783 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 784 Scope = addLocalScopeForVarDecl(VD, Scope); 785 } 786 return Scope; 787} 788 789/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 790/// create add scope for automatic objects and temporary objects bound to 791/// const reference. Will reuse Scope if not NULL. 792LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 793 LocalScope* Scope) { 794 if (!BuildOpts.AddImplicitDtors) 795 return Scope; 796 797 // Check if variable is local. 798 switch (VD->getStorageClass()) { 799 case SC_None: 800 case SC_Auto: 801 case SC_Register: 802 break; 803 default: return Scope; 804 } 805 806 // Check for const references bound to temporary. Set type to pointee. 807 QualType QT = VD->getType(); 808 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 809 QT = RT->getPointeeType(); 810 if (!QT.isConstQualified()) 811 return Scope; 812 if (!VD->extendsLifetimeOfTemporary()) 813 return Scope; 814 } 815 816 // Check for constant size array. Set type to array element type. 817 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 818 if (AT->getSize() == 0) 819 return Scope; 820 QT = AT->getElementType(); 821 } 822 823 // Check if type is a C++ class with non-trivial destructor. 824 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 825 if (!CD->hasTrivialDestructor()) { 826 // Add the variable to scope 827 Scope = createOrReuseLocalScope(Scope); 828 Scope->addVar(VD); 829 ScopePos = Scope->begin(); 830 } 831 return Scope; 832} 833 834/// addLocalScopeAndDtors - For given statement add local scope for it and 835/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 836void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 837 if (!BuildOpts.AddImplicitDtors) 838 return; 839 840 LocalScope::const_iterator scopeBeginPos = ScopePos; 841 addLocalScopeForStmt(S); 842 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 843} 844 845/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 846/// variables with automatic storage duration to CFGBlock's elements vector. 847/// Elements will be prepended to physical beginning of the vector which 848/// happens to be logical end. Use blocks terminator as statement that specifies 849/// destructors call site. 850/// FIXME: This mechanism for adding automatic destructors doesn't handle 851/// no-return destructors properly. 852void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 853 LocalScope::const_iterator B, LocalScope::const_iterator E) { 854 BumpVectorContext &C = cfg->getBumpVectorContext(); 855 CFGBlock::iterator InsertPos 856 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 857 for (LocalScope::const_iterator I = B; I != E; ++I) 858 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 859 Blk->getTerminator()); 860} 861 862/// Visit - Walk the subtree of a statement and add extra 863/// blocks for ternary operators, &&, and ||. We also process "," and 864/// DeclStmts (which may contain nested control-flow). 865CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 866 if (!S) { 867 badCFG = true; 868 return 0; 869 } 870 871 if (Expr *E = dyn_cast<Expr>(S)) 872 S = E->IgnoreParens(); 873 874 switch (S->getStmtClass()) { 875 default: 876 return VisitStmt(S, asc); 877 878 case Stmt::AddrLabelExprClass: 879 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 880 881 case Stmt::BinaryConditionalOperatorClass: 882 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 883 884 case Stmt::BinaryOperatorClass: 885 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 886 887 case Stmt::BlockExprClass: 888 return VisitBlockExpr(cast<BlockExpr>(S), asc); 889 890 case Stmt::BreakStmtClass: 891 return VisitBreakStmt(cast<BreakStmt>(S)); 892 893 case Stmt::CallExprClass: 894 case Stmt::CXXOperatorCallExprClass: 895 case Stmt::CXXMemberCallExprClass: 896 return VisitCallExpr(cast<CallExpr>(S), asc); 897 898 case Stmt::CaseStmtClass: 899 return VisitCaseStmt(cast<CaseStmt>(S)); 900 901 case Stmt::ChooseExprClass: 902 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 903 904 case Stmt::CompoundStmtClass: 905 return VisitCompoundStmt(cast<CompoundStmt>(S)); 906 907 case Stmt::ConditionalOperatorClass: 908 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 909 910 case Stmt::ContinueStmtClass: 911 return VisitContinueStmt(cast<ContinueStmt>(S)); 912 913 case Stmt::CXXCatchStmtClass: 914 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 915 916 case Stmt::ExprWithCleanupsClass: 917 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 918 919 case Stmt::CXXBindTemporaryExprClass: 920 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 921 922 case Stmt::CXXConstructExprClass: 923 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 924 925 case Stmt::CXXFunctionalCastExprClass: 926 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 927 928 case Stmt::CXXTemporaryObjectExprClass: 929 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 930 931 case Stmt::CXXThrowExprClass: 932 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 933 934 case Stmt::CXXTryStmtClass: 935 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 936 937 case Stmt::CXXForRangeStmtClass: 938 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 939 940 case Stmt::DeclStmtClass: 941 return VisitDeclStmt(cast<DeclStmt>(S)); 942 943 case Stmt::DefaultStmtClass: 944 return VisitDefaultStmt(cast<DefaultStmt>(S)); 945 946 case Stmt::DoStmtClass: 947 return VisitDoStmt(cast<DoStmt>(S)); 948 949 case Stmt::ForStmtClass: 950 return VisitForStmt(cast<ForStmt>(S)); 951 952 case Stmt::GotoStmtClass: 953 return VisitGotoStmt(cast<GotoStmt>(S)); 954 955 case Stmt::IfStmtClass: 956 return VisitIfStmt(cast<IfStmt>(S)); 957 958 case Stmt::ImplicitCastExprClass: 959 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 960 961 case Stmt::IndirectGotoStmtClass: 962 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 963 964 case Stmt::LabelStmtClass: 965 return VisitLabelStmt(cast<LabelStmt>(S)); 966 967 case Stmt::MemberExprClass: 968 return VisitMemberExpr(cast<MemberExpr>(S), asc); 969 970 case Stmt::ObjCAtCatchStmtClass: 971 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 972 973 case Stmt::ObjCAtSynchronizedStmtClass: 974 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 975 976 case Stmt::ObjCAtThrowStmtClass: 977 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 978 979 case Stmt::ObjCAtTryStmtClass: 980 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 981 982 case Stmt::ObjCForCollectionStmtClass: 983 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 984 985 case Stmt::NullStmtClass: 986 return Block; 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::VisitWhileStmt(WhileStmt *W) { 1915 CFGBlock *LoopSuccessor = NULL; 1916 1917 // Save local scope position because in case of condition variable ScopePos 1918 // won't be restored when traversing AST. 1919 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1920 1921 // Create local scope for possible condition variable. 1922 // Store scope position for continue statement. 1923 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1924 if (VarDecl *VD = W->getConditionVariable()) { 1925 addLocalScopeForVarDecl(VD); 1926 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1927 } 1928 1929 // "while" is a control-flow statement. Thus we stop processing the current 1930 // block. 1931 if (Block) { 1932 if (badCFG) 1933 return 0; 1934 LoopSuccessor = Block; 1935 Block = 0; 1936 } else 1937 LoopSuccessor = Succ; 1938 1939 // Because of short-circuit evaluation, the condition of the loop can span 1940 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1941 // evaluate the condition. 1942 CFGBlock *ExitConditionBlock = createBlock(false); 1943 CFGBlock *EntryConditionBlock = ExitConditionBlock; 1944 1945 // Set the terminator for the "exit" condition block. 1946 ExitConditionBlock->setTerminator(W); 1947 1948 // Now add the actual condition to the condition block. Because the condition 1949 // itself may contain control-flow, new blocks may be created. Thus we update 1950 // "Succ" after adding the condition. 1951 if (Stmt *C = W->getCond()) { 1952 Block = ExitConditionBlock; 1953 EntryConditionBlock = addStmt(C); 1954 // The condition might finish the current 'Block'. 1955 Block = EntryConditionBlock; 1956 1957 // If this block contains a condition variable, add both the condition 1958 // variable and initializer to the CFG. 1959 if (VarDecl *VD = W->getConditionVariable()) { 1960 if (Expr *Init = VD->getInit()) { 1961 autoCreateBlock(); 1962 appendStmt(Block, W->getConditionVariableDeclStmt()); 1963 EntryConditionBlock = addStmt(Init); 1964 assert(Block == EntryConditionBlock); 1965 } 1966 } 1967 1968 if (Block) { 1969 if (badCFG) 1970 return 0; 1971 } 1972 } 1973 1974 // The condition block is the implicit successor for the loop body as well as 1975 // any code above the loop. 1976 Succ = EntryConditionBlock; 1977 1978 // See if this is a known constant. 1979 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1980 1981 // Process the loop body. 1982 { 1983 assert(W->getBody()); 1984 1985 // Save the current values for Block, Succ, and continue and break targets 1986 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1987 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1988 save_break(BreakJumpTarget); 1989 1990 // Create an empty block to represent the transition block for looping back 1991 // to the head of the loop. 1992 Block = 0; 1993 assert(Succ == EntryConditionBlock); 1994 Succ = createBlock(); 1995 Succ->setLoopTarget(W); 1996 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1997 1998 // All breaks should go to the code following the loop. 1999 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2000 2001 // NULL out Block to force lazy instantiation of blocks for the body. 2002 Block = NULL; 2003 2004 // Loop body should end with destructor of Condition variable (if any). 2005 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2006 2007 // If body is not a compound statement create implicit scope 2008 // and add destructors. 2009 if (!isa<CompoundStmt>(W->getBody())) 2010 addLocalScopeAndDtors(W->getBody()); 2011 2012 // Create the body. The returned block is the entry to the loop body. 2013 CFGBlock *BodyBlock = addStmt(W->getBody()); 2014 2015 if (!BodyBlock) 2016 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2017 else if (Block) { 2018 if (badCFG) 2019 return 0; 2020 } 2021 2022 // Add the loop body entry as a successor to the condition. 2023 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2024 } 2025 2026 // Link up the condition block with the code that follows the loop. (the 2027 // false branch). 2028 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2029 2030 // There can be no more statements in the condition block since we loop back 2031 // to this block. NULL out Block to force lazy creation of another block. 2032 Block = NULL; 2033 2034 // Return the condition block, which is the dominating block for the loop. 2035 Succ = EntryConditionBlock; 2036 return EntryConditionBlock; 2037} 2038 2039 2040CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2041 // FIXME: For now we pretend that @catch and the code it contains does not 2042 // exit. 2043 return Block; 2044} 2045 2046CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2047 // FIXME: This isn't complete. We basically treat @throw like a return 2048 // statement. 2049 2050 // If we were in the middle of a block we stop processing that block. 2051 if (badCFG) 2052 return 0; 2053 2054 // Create the new block. 2055 Block = createBlock(false); 2056 2057 // The Exit block is the only successor. 2058 addSuccessor(Block, &cfg->getExit()); 2059 2060 // Add the statement to the block. This may create new blocks if S contains 2061 // control-flow (short-circuit operations). 2062 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2063} 2064 2065CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2066 // If we were in the middle of a block we stop processing that block. 2067 if (badCFG) 2068 return 0; 2069 2070 // Create the new block. 2071 Block = createBlock(false); 2072 2073 if (TryTerminatedBlock) 2074 // The current try statement is the only successor. 2075 addSuccessor(Block, TryTerminatedBlock); 2076 else 2077 // otherwise the Exit block is the only successor. 2078 addSuccessor(Block, &cfg->getExit()); 2079 2080 // Add the statement to the block. This may create new blocks if S contains 2081 // control-flow (short-circuit operations). 2082 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2083} 2084 2085CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2086 CFGBlock *LoopSuccessor = NULL; 2087 2088 // "do...while" is a control-flow statement. Thus we stop processing the 2089 // current block. 2090 if (Block) { 2091 if (badCFG) 2092 return 0; 2093 LoopSuccessor = Block; 2094 } else 2095 LoopSuccessor = Succ; 2096 2097 // Because of short-circuit evaluation, the condition of the loop can span 2098 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2099 // evaluate the condition. 2100 CFGBlock *ExitConditionBlock = createBlock(false); 2101 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2102 2103 // Set the terminator for the "exit" condition block. 2104 ExitConditionBlock->setTerminator(D); 2105 2106 // Now add the actual condition to the condition block. Because the condition 2107 // itself may contain control-flow, new blocks may be created. 2108 if (Stmt *C = D->getCond()) { 2109 Block = ExitConditionBlock; 2110 EntryConditionBlock = addStmt(C); 2111 if (Block) { 2112 if (badCFG) 2113 return 0; 2114 } 2115 } 2116 2117 // The condition block is the implicit successor for the loop body. 2118 Succ = EntryConditionBlock; 2119 2120 // See if this is a known constant. 2121 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2122 2123 // Process the loop body. 2124 CFGBlock *BodyBlock = NULL; 2125 { 2126 assert(D->getBody()); 2127 2128 // Save the current values for Block, Succ, and continue and break targets 2129 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2130 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2131 save_break(BreakJumpTarget); 2132 2133 // All continues within this loop should go to the condition block 2134 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2135 2136 // All breaks should go to the code following the loop. 2137 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2138 2139 // NULL out Block to force lazy instantiation of blocks for the body. 2140 Block = NULL; 2141 2142 // If body is not a compound statement create implicit scope 2143 // and add destructors. 2144 if (!isa<CompoundStmt>(D->getBody())) 2145 addLocalScopeAndDtors(D->getBody()); 2146 2147 // Create the body. The returned block is the entry to the loop body. 2148 BodyBlock = addStmt(D->getBody()); 2149 2150 if (!BodyBlock) 2151 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2152 else if (Block) { 2153 if (badCFG) 2154 return 0; 2155 } 2156 2157 if (!KnownVal.isFalse()) { 2158 // Add an intermediate block between the BodyBlock and the 2159 // ExitConditionBlock to represent the "loop back" transition. Create an 2160 // empty block to represent the transition block for looping back to the 2161 // head of the loop. 2162 // FIXME: Can we do this more efficiently without adding another block? 2163 Block = NULL; 2164 Succ = BodyBlock; 2165 CFGBlock *LoopBackBlock = createBlock(); 2166 LoopBackBlock->setLoopTarget(D); 2167 2168 // Add the loop body entry as a successor to the condition. 2169 addSuccessor(ExitConditionBlock, LoopBackBlock); 2170 } 2171 else 2172 addSuccessor(ExitConditionBlock, NULL); 2173 } 2174 2175 // Link up the condition block with the code that follows the loop. 2176 // (the false branch). 2177 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2178 2179 // There can be no more statements in the body block(s) since we loop back to 2180 // the body. NULL out Block to force lazy creation of another block. 2181 Block = NULL; 2182 2183 // Return the loop body, which is the dominating block for the loop. 2184 Succ = BodyBlock; 2185 return BodyBlock; 2186} 2187 2188CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2189 // "continue" is a control-flow statement. Thus we stop processing the 2190 // current block. 2191 if (badCFG) 2192 return 0; 2193 2194 // Now create a new block that ends with the continue statement. 2195 Block = createBlock(false); 2196 Block->setTerminator(C); 2197 2198 // If there is no target for the continue, then we are looking at an 2199 // incomplete AST. This means the CFG cannot be constructed. 2200 if (ContinueJumpTarget.block) { 2201 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2202 addSuccessor(Block, ContinueJumpTarget.block); 2203 } else 2204 badCFG = true; 2205 2206 return Block; 2207} 2208 2209CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2210 AddStmtChoice asc) { 2211 2212 if (asc.alwaysAdd(*this, E)) { 2213 autoCreateBlock(); 2214 appendStmt(Block, E); 2215 } 2216 2217 // VLA types have expressions that must be evaluated. 2218 CFGBlock *lastBlock = Block; 2219 2220 if (E->isArgumentType()) { 2221 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2222 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2223 lastBlock = addStmt(VA->getSizeExpr()); 2224 } 2225 return lastBlock; 2226} 2227 2228/// VisitStmtExpr - Utility method to handle (nested) statement 2229/// expressions (a GCC extension). 2230CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2231 if (asc.alwaysAdd(*this, SE)) { 2232 autoCreateBlock(); 2233 appendStmt(Block, SE); 2234 } 2235 return VisitCompoundStmt(SE->getSubStmt()); 2236} 2237 2238CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2239 // "switch" is a control-flow statement. Thus we stop processing the current 2240 // block. 2241 CFGBlock *SwitchSuccessor = NULL; 2242 2243 // Save local scope position because in case of condition variable ScopePos 2244 // won't be restored when traversing AST. 2245 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2246 2247 // Create local scope for possible condition variable. 2248 // Store scope position. Add implicit destructor. 2249 if (VarDecl *VD = Terminator->getConditionVariable()) { 2250 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2251 addLocalScopeForVarDecl(VD); 2252 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2253 } 2254 2255 if (Block) { 2256 if (badCFG) 2257 return 0; 2258 SwitchSuccessor = Block; 2259 } else SwitchSuccessor = Succ; 2260 2261 // Save the current "switch" context. 2262 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2263 save_default(DefaultCaseBlock); 2264 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2265 2266 // Set the "default" case to be the block after the switch statement. If the 2267 // switch statement contains a "default:", this value will be overwritten with 2268 // the block for that code. 2269 DefaultCaseBlock = SwitchSuccessor; 2270 2271 // Create a new block that will contain the switch statement. 2272 SwitchTerminatedBlock = createBlock(false); 2273 2274 // Now process the switch body. The code after the switch is the implicit 2275 // successor. 2276 Succ = SwitchSuccessor; 2277 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2278 2279 // When visiting the body, the case statements should automatically get linked 2280 // up to the switch. We also don't keep a pointer to the body, since all 2281 // control-flow from the switch goes to case/default statements. 2282 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2283 Block = NULL; 2284 2285 // For pruning unreachable case statements, save the current state 2286 // for tracking the condition value. 2287 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2288 false); 2289 2290 // Determine if the switch condition can be explicitly evaluated. 2291 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2292 Expr::EvalResult result; 2293 bool b = tryEvaluate(Terminator->getCond(), result); 2294 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2295 b ? &result : 0); 2296 2297 // If body is not a compound statement create implicit scope 2298 // and add destructors. 2299 if (!isa<CompoundStmt>(Terminator->getBody())) 2300 addLocalScopeAndDtors(Terminator->getBody()); 2301 2302 addStmt(Terminator->getBody()); 2303 if (Block) { 2304 if (badCFG) 2305 return 0; 2306 } 2307 2308 // If we have no "default:" case, the default transition is to the code 2309 // following the switch body. Moreover, take into account if all the 2310 // cases of a switch are covered (e.g., switching on an enum value). 2311 addSuccessor(SwitchTerminatedBlock, 2312 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2313 ? 0 : DefaultCaseBlock); 2314 2315 // Add the terminator and condition in the switch block. 2316 SwitchTerminatedBlock->setTerminator(Terminator); 2317 Block = SwitchTerminatedBlock; 2318 Block = addStmt(Terminator->getCond()); 2319 2320 // Finally, if the SwitchStmt contains a condition variable, add both the 2321 // SwitchStmt and the condition variable initialization to the CFG. 2322 if (VarDecl *VD = Terminator->getConditionVariable()) { 2323 if (Expr *Init = VD->getInit()) { 2324 autoCreateBlock(); 2325 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2326 addStmt(Init); 2327 } 2328 } 2329 2330 return Block; 2331} 2332 2333static bool shouldAddCase(bool &switchExclusivelyCovered, 2334 const Expr::EvalResult *switchCond, 2335 const CaseStmt *CS, 2336 ASTContext &Ctx) { 2337 if (!switchCond) 2338 return true; 2339 2340 bool addCase = false; 2341 2342 if (!switchExclusivelyCovered) { 2343 if (switchCond->Val.isInt()) { 2344 // Evaluate the LHS of the case value. 2345 Expr::EvalResult V1; 2346 CS->getLHS()->Evaluate(V1, Ctx); 2347 assert(V1.Val.isInt()); 2348 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2349 const llvm::APSInt &lhsInt = V1.Val.getInt(); 2350 2351 if (condInt == lhsInt) { 2352 addCase = true; 2353 switchExclusivelyCovered = true; 2354 } 2355 else if (condInt < lhsInt) { 2356 if (const Expr *RHS = CS->getRHS()) { 2357 // Evaluate the RHS of the case value. 2358 Expr::EvalResult V2; 2359 RHS->Evaluate(V2, Ctx); 2360 assert(V2.Val.isInt()); 2361 if (V2.Val.getInt() <= condInt) { 2362 addCase = true; 2363 switchExclusivelyCovered = true; 2364 } 2365 } 2366 } 2367 } 2368 else 2369 addCase = true; 2370 } 2371 return addCase; 2372} 2373 2374CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2375 // CaseStmts are essentially labels, so they are the first statement in a 2376 // block. 2377 CFGBlock *TopBlock = 0, *LastBlock = 0; 2378 2379 if (Stmt *Sub = CS->getSubStmt()) { 2380 // For deeply nested chains of CaseStmts, instead of doing a recursion 2381 // (which can blow out the stack), manually unroll and create blocks 2382 // along the way. 2383 while (isa<CaseStmt>(Sub)) { 2384 CFGBlock *currentBlock = createBlock(false); 2385 currentBlock->setLabel(CS); 2386 2387 if (TopBlock) 2388 addSuccessor(LastBlock, currentBlock); 2389 else 2390 TopBlock = currentBlock; 2391 2392 addSuccessor(SwitchTerminatedBlock, 2393 shouldAddCase(switchExclusivelyCovered, switchCond, 2394 CS, *Context) 2395 ? currentBlock : 0); 2396 2397 LastBlock = currentBlock; 2398 CS = cast<CaseStmt>(Sub); 2399 Sub = CS->getSubStmt(); 2400 } 2401 2402 addStmt(Sub); 2403 } 2404 2405 CFGBlock *CaseBlock = Block; 2406 if (!CaseBlock) 2407 CaseBlock = createBlock(); 2408 2409 // Cases statements partition blocks, so this is the top of the basic block we 2410 // were processing (the "case XXX:" is the label). 2411 CaseBlock->setLabel(CS); 2412 2413 if (badCFG) 2414 return 0; 2415 2416 // Add this block to the list of successors for the block with the switch 2417 // statement. 2418 assert(SwitchTerminatedBlock); 2419 addSuccessor(SwitchTerminatedBlock, 2420 shouldAddCase(switchExclusivelyCovered, switchCond, 2421 CS, *Context) 2422 ? CaseBlock : 0); 2423 2424 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2425 Block = NULL; 2426 2427 if (TopBlock) { 2428 addSuccessor(LastBlock, CaseBlock); 2429 Succ = TopBlock; 2430 } else { 2431 // This block is now the implicit successor of other blocks. 2432 Succ = CaseBlock; 2433 } 2434 2435 return Succ; 2436} 2437 2438CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2439 if (Terminator->getSubStmt()) 2440 addStmt(Terminator->getSubStmt()); 2441 2442 DefaultCaseBlock = Block; 2443 2444 if (!DefaultCaseBlock) 2445 DefaultCaseBlock = createBlock(); 2446 2447 // Default statements partition blocks, so this is the top of the basic block 2448 // we were processing (the "default:" is the label). 2449 DefaultCaseBlock->setLabel(Terminator); 2450 2451 if (badCFG) 2452 return 0; 2453 2454 // Unlike case statements, we don't add the default block to the successors 2455 // for the switch statement immediately. This is done when we finish 2456 // processing the switch statement. This allows for the default case 2457 // (including a fall-through to the code after the switch statement) to always 2458 // be the last successor of a switch-terminated block. 2459 2460 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2461 Block = NULL; 2462 2463 // This block is now the implicit successor of other blocks. 2464 Succ = DefaultCaseBlock; 2465 2466 return DefaultCaseBlock; 2467} 2468 2469CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2470 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2471 // current block. 2472 CFGBlock *TrySuccessor = NULL; 2473 2474 if (Block) { 2475 if (badCFG) 2476 return 0; 2477 TrySuccessor = Block; 2478 } else TrySuccessor = Succ; 2479 2480 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2481 2482 // Create a new block that will contain the try statement. 2483 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2484 // Add the terminator in the try block. 2485 NewTryTerminatedBlock->setTerminator(Terminator); 2486 2487 bool HasCatchAll = false; 2488 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2489 // The code after the try is the implicit successor. 2490 Succ = TrySuccessor; 2491 CXXCatchStmt *CS = Terminator->getHandler(h); 2492 if (CS->getExceptionDecl() == 0) { 2493 HasCatchAll = true; 2494 } 2495 Block = NULL; 2496 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2497 if (CatchBlock == 0) 2498 return 0; 2499 // Add this block to the list of successors for the block with the try 2500 // statement. 2501 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2502 } 2503 if (!HasCatchAll) { 2504 if (PrevTryTerminatedBlock) 2505 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2506 else 2507 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2508 } 2509 2510 // The code after the try is the implicit successor. 2511 Succ = TrySuccessor; 2512 2513 // Save the current "try" context. 2514 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2515 cfg->addTryDispatchBlock(TryTerminatedBlock); 2516 2517 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2518 Block = NULL; 2519 Block = addStmt(Terminator->getTryBlock()); 2520 return Block; 2521} 2522 2523CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2524 // CXXCatchStmt are treated like labels, so they are the first statement in a 2525 // block. 2526 2527 // Save local scope position because in case of exception variable ScopePos 2528 // won't be restored when traversing AST. 2529 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2530 2531 // Create local scope for possible exception variable. 2532 // Store scope position. Add implicit destructor. 2533 if (VarDecl *VD = CS->getExceptionDecl()) { 2534 LocalScope::const_iterator BeginScopePos = ScopePos; 2535 addLocalScopeForVarDecl(VD); 2536 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2537 } 2538 2539 if (CS->getHandlerBlock()) 2540 addStmt(CS->getHandlerBlock()); 2541 2542 CFGBlock *CatchBlock = Block; 2543 if (!CatchBlock) 2544 CatchBlock = createBlock(); 2545 2546 CatchBlock->setLabel(CS); 2547 2548 if (badCFG) 2549 return 0; 2550 2551 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2552 Block = NULL; 2553 2554 return CatchBlock; 2555} 2556 2557CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2558 // C++0x for-range statements are specified as [stmt.ranged]: 2559 // 2560 // { 2561 // auto && __range = range-init; 2562 // for ( auto __begin = begin-expr, 2563 // __end = end-expr; 2564 // __begin != __end; 2565 // ++__begin ) { 2566 // for-range-declaration = *__begin; 2567 // statement 2568 // } 2569 // } 2570 2571 // Save local scope position before the addition of the implicit variables. 2572 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2573 2574 // Create local scopes and destructors for range, begin and end variables. 2575 if (Stmt *Range = S->getRangeStmt()) 2576 addLocalScopeForStmt(Range); 2577 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2578 addLocalScopeForStmt(BeginEnd); 2579 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2580 2581 LocalScope::const_iterator ContinueScopePos = ScopePos; 2582 2583 // "for" is a control-flow statement. Thus we stop processing the current 2584 // block. 2585 CFGBlock *LoopSuccessor = NULL; 2586 if (Block) { 2587 if (badCFG) 2588 return 0; 2589 LoopSuccessor = Block; 2590 } else 2591 LoopSuccessor = Succ; 2592 2593 // Save the current value for the break targets. 2594 // All breaks should go to the code following the loop. 2595 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2596 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2597 2598 // The block for the __begin != __end expression. 2599 CFGBlock *ConditionBlock = createBlock(false); 2600 ConditionBlock->setTerminator(S); 2601 2602 // Now add the actual condition to the condition block. 2603 if (Expr *C = S->getCond()) { 2604 Block = ConditionBlock; 2605 CFGBlock *BeginConditionBlock = addStmt(C); 2606 if (badCFG) 2607 return 0; 2608 assert(BeginConditionBlock == ConditionBlock && 2609 "condition block in for-range was unexpectedly complex"); 2610 (void)BeginConditionBlock; 2611 } 2612 2613 // The condition block is the implicit successor for the loop body as well as 2614 // any code above the loop. 2615 Succ = ConditionBlock; 2616 2617 // See if this is a known constant. 2618 TryResult KnownVal(true); 2619 2620 if (S->getCond()) 2621 KnownVal = tryEvaluateBool(S->getCond()); 2622 2623 // Now create the loop body. 2624 { 2625 assert(S->getBody()); 2626 2627 // Save the current values for Block, Succ, and continue targets. 2628 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2629 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2630 2631 // Generate increment code in its own basic block. This is the target of 2632 // continue statements. 2633 Block = 0; 2634 Succ = addStmt(S->getInc()); 2635 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2636 2637 // The starting block for the loop increment is the block that should 2638 // represent the 'loop target' for looping back to the start of the loop. 2639 ContinueJumpTarget.block->setLoopTarget(S); 2640 2641 // Finish up the increment block and prepare to start the loop body. 2642 assert(Block); 2643 if (badCFG) 2644 return 0; 2645 Block = 0; 2646 2647 2648 // Add implicit scope and dtors for loop variable. 2649 addLocalScopeAndDtors(S->getLoopVarStmt()); 2650 2651 // Populate a new block to contain the loop body and loop variable. 2652 Block = addStmt(S->getBody()); 2653 if (badCFG) 2654 return 0; 2655 Block = addStmt(S->getLoopVarStmt()); 2656 if (badCFG) 2657 return 0; 2658 2659 // This new body block is a successor to our condition block. 2660 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2661 } 2662 2663 // Link up the condition block with the code that follows the loop (the 2664 // false branch). 2665 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2666 2667 // Add the initialization statements. 2668 Block = createBlock(); 2669 addStmt(S->getBeginEndStmt()); 2670 return addStmt(S->getRangeStmt()); 2671} 2672 2673CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2674 AddStmtChoice asc) { 2675 if (BuildOpts.AddImplicitDtors) { 2676 // If adding implicit destructors visit the full expression for adding 2677 // destructors of temporaries. 2678 VisitForTemporaryDtors(E->getSubExpr()); 2679 2680 // Full expression has to be added as CFGStmt so it will be sequenced 2681 // before destructors of it's temporaries. 2682 asc = asc.withAlwaysAdd(true); 2683 } 2684 return Visit(E->getSubExpr(), asc); 2685} 2686 2687CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2688 AddStmtChoice asc) { 2689 if (asc.alwaysAdd(*this, E)) { 2690 autoCreateBlock(); 2691 appendStmt(Block, E); 2692 2693 // We do not want to propagate the AlwaysAdd property. 2694 asc = asc.withAlwaysAdd(false); 2695 } 2696 return Visit(E->getSubExpr(), asc); 2697} 2698 2699CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2700 AddStmtChoice asc) { 2701 autoCreateBlock(); 2702 if (!C->isElidable()) 2703 appendStmt(Block, C); 2704 2705 return VisitChildren(C); 2706} 2707 2708CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2709 AddStmtChoice asc) { 2710 if (asc.alwaysAdd(*this, E)) { 2711 autoCreateBlock(); 2712 appendStmt(Block, E); 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::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2720 AddStmtChoice asc) { 2721 autoCreateBlock(); 2722 appendStmt(Block, C); 2723 return VisitChildren(C); 2724} 2725 2726CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2727 AddStmtChoice asc) { 2728 if (asc.alwaysAdd(*this, E)) { 2729 autoCreateBlock(); 2730 appendStmt(Block, E); 2731 } 2732 return Visit(E->getSubExpr(), AddStmtChoice()); 2733} 2734 2735CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 2736 // Lazily create the indirect-goto dispatch block if there isn't one already. 2737 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 2738 2739 if (!IBlock) { 2740 IBlock = createBlock(false); 2741 cfg->setIndirectGotoBlock(IBlock); 2742 } 2743 2744 // IndirectGoto is a control-flow statement. Thus we stop processing the 2745 // current block and create a new one. 2746 if (badCFG) 2747 return 0; 2748 2749 Block = createBlock(false); 2750 Block->setTerminator(I); 2751 addSuccessor(Block, IBlock); 2752 return addStmt(I->getTarget()); 2753} 2754 2755CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2756tryAgain: 2757 if (!E) { 2758 badCFG = true; 2759 return NULL; 2760 } 2761 switch (E->getStmtClass()) { 2762 default: 2763 return VisitChildrenForTemporaryDtors(E); 2764 2765 case Stmt::BinaryOperatorClass: 2766 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2767 2768 case Stmt::CXXBindTemporaryExprClass: 2769 return VisitCXXBindTemporaryExprForTemporaryDtors( 2770 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2771 2772 case Stmt::BinaryConditionalOperatorClass: 2773 case Stmt::ConditionalOperatorClass: 2774 return VisitConditionalOperatorForTemporaryDtors( 2775 cast<AbstractConditionalOperator>(E), BindToTemporary); 2776 2777 case Stmt::ImplicitCastExprClass: 2778 // For implicit cast we want BindToTemporary to be passed further. 2779 E = cast<CastExpr>(E)->getSubExpr(); 2780 goto tryAgain; 2781 2782 case Stmt::ParenExprClass: 2783 E = cast<ParenExpr>(E)->getSubExpr(); 2784 goto tryAgain; 2785 2786 case Stmt::MaterializeTemporaryExprClass: 2787 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 2788 goto tryAgain; 2789 } 2790} 2791 2792CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2793 // When visiting children for destructors we want to visit them in reverse 2794 // order. Because there's no reverse iterator for children must to reverse 2795 // them in helper vector. 2796 typedef SmallVector<Stmt *, 4> ChildrenVect; 2797 ChildrenVect ChildrenRev; 2798 for (Stmt::child_range I = E->children(); I; ++I) { 2799 if (*I) ChildrenRev.push_back(*I); 2800 } 2801 2802 CFGBlock *B = Block; 2803 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2804 L = ChildrenRev.rend(); I != L; ++I) { 2805 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2806 B = R; 2807 } 2808 return B; 2809} 2810 2811CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2812 if (E->isLogicalOp()) { 2813 // Destructors for temporaries in LHS expression should be called after 2814 // those for RHS expression. Even if this will unnecessarily create a block, 2815 // this block will be used at least by the full expression. 2816 autoCreateBlock(); 2817 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2818 if (badCFG) 2819 return NULL; 2820 2821 Succ = ConfluenceBlock; 2822 Block = NULL; 2823 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2824 2825 if (RHSBlock) { 2826 if (badCFG) 2827 return NULL; 2828 2829 // If RHS expression did produce destructors we need to connect created 2830 // blocks to CFG in same manner as for binary operator itself. 2831 CFGBlock *LHSBlock = createBlock(false); 2832 LHSBlock->setTerminator(CFGTerminator(E, true)); 2833 2834 // For binary operator LHS block is before RHS in list of predecessors 2835 // of ConfluenceBlock. 2836 std::reverse(ConfluenceBlock->pred_begin(), 2837 ConfluenceBlock->pred_end()); 2838 2839 // See if this is a known constant. 2840 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2841 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2842 KnownVal.negate(); 2843 2844 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2845 // itself. 2846 if (E->getOpcode() == BO_LOr) { 2847 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2848 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2849 } else { 2850 assert (E->getOpcode() == BO_LAnd); 2851 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2852 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2853 } 2854 2855 Block = LHSBlock; 2856 return LHSBlock; 2857 } 2858 2859 Block = ConfluenceBlock; 2860 return ConfluenceBlock; 2861 } 2862 2863 if (E->isAssignmentOp()) { 2864 // For assignment operator (=) LHS expression is visited 2865 // before RHS expression. For destructors visit them in reverse order. 2866 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2867 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2868 return LHSBlock ? LHSBlock : RHSBlock; 2869 } 2870 2871 // For any other binary operator RHS expression is visited before 2872 // LHS expression (order of children). For destructors visit them in reverse 2873 // order. 2874 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2875 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2876 return RHSBlock ? RHSBlock : LHSBlock; 2877} 2878 2879CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2880 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2881 // First add destructors for temporaries in subexpression. 2882 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2883 if (!BindToTemporary) { 2884 // If lifetime of temporary is not prolonged (by assigning to constant 2885 // reference) add destructor for it. 2886 2887 // If the destructor is marked as a no-return destructor, we need to create 2888 // a new block for the destructor which does not have as a successor 2889 // anything built thus far. Control won't flow out of this block. 2890 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 2891 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 2892 Block = createNoReturnBlock(); 2893 else 2894 autoCreateBlock(); 2895 2896 appendTemporaryDtor(Block, E); 2897 B = Block; 2898 } 2899 return B; 2900} 2901 2902CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2903 AbstractConditionalOperator *E, bool BindToTemporary) { 2904 // First add destructors for condition expression. Even if this will 2905 // unnecessarily create a block, this block will be used at least by the full 2906 // expression. 2907 autoCreateBlock(); 2908 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2909 if (badCFG) 2910 return NULL; 2911 if (BinaryConditionalOperator *BCO 2912 = dyn_cast<BinaryConditionalOperator>(E)) { 2913 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2914 if (badCFG) 2915 return NULL; 2916 } 2917 2918 // Try to add block with destructors for LHS expression. 2919 CFGBlock *LHSBlock = NULL; 2920 Succ = ConfluenceBlock; 2921 Block = NULL; 2922 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2923 if (badCFG) 2924 return NULL; 2925 2926 // Try to add block with destructors for RHS expression; 2927 Succ = ConfluenceBlock; 2928 Block = NULL; 2929 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2930 BindToTemporary); 2931 if (badCFG) 2932 return NULL; 2933 2934 if (!RHSBlock && !LHSBlock) { 2935 // If neither LHS nor RHS expression had temporaries to destroy don't create 2936 // more blocks. 2937 Block = ConfluenceBlock; 2938 return Block; 2939 } 2940 2941 Block = createBlock(false); 2942 Block->setTerminator(CFGTerminator(E, true)); 2943 2944 // See if this is a known constant. 2945 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2946 2947 if (LHSBlock) { 2948 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2949 } else if (KnownVal.isFalse()) { 2950 addSuccessor(Block, NULL); 2951 } else { 2952 addSuccessor(Block, ConfluenceBlock); 2953 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2954 } 2955 2956 if (!RHSBlock) 2957 RHSBlock = ConfluenceBlock; 2958 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2959 2960 return Block; 2961} 2962 2963} // end anonymous namespace 2964 2965/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2966/// no successors or predecessors. If this is the first block created in the 2967/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2968CFGBlock *CFG::createBlock() { 2969 bool first_block = begin() == end(); 2970 2971 // Create the block. 2972 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2973 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2974 Blocks.push_back(Mem, BlkBVC); 2975 2976 // If this is the first block, set it as the Entry and Exit. 2977 if (first_block) 2978 Entry = Exit = &back(); 2979 2980 // Return the block. 2981 return &back(); 2982} 2983 2984/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2985/// CFG is returned to the caller. 2986CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 2987 const BuildOptions &BO) { 2988 CFGBuilder Builder(C, BO); 2989 return Builder.buildCFG(D, Statement); 2990} 2991 2992const CXXDestructorDecl * 2993CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 2994 switch (getKind()) { 2995 case CFGElement::Invalid: 2996 case CFGElement::Statement: 2997 case CFGElement::Initializer: 2998 llvm_unreachable("getDestructorDecl should only be used with " 2999 "ImplicitDtors"); 3000 case CFGElement::AutomaticObjectDtor: { 3001 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 3002 QualType ty = var->getType(); 3003 ty = ty.getNonReferenceType(); 3004 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3005 ty = arrayType->getElementType(); 3006 } 3007 const RecordType *recordType = ty->getAs<RecordType>(); 3008 const CXXRecordDecl *classDecl = 3009 cast<CXXRecordDecl>(recordType->getDecl()); 3010 return classDecl->getDestructor(); 3011 } 3012 case CFGElement::TemporaryDtor: { 3013 const CXXBindTemporaryExpr *bindExpr = 3014 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 3015 const CXXTemporary *temp = bindExpr->getTemporary(); 3016 return temp->getDestructor(); 3017 } 3018 case CFGElement::BaseDtor: 3019 case CFGElement::MemberDtor: 3020 3021 // Not yet supported. 3022 return 0; 3023 } 3024 llvm_unreachable("getKind() returned bogus value"); 3025 return 0; 3026} 3027 3028bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3029 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 3030 QualType ty = cdecl->getType(); 3031 return cast<FunctionType>(ty)->getNoReturnAttr(); 3032 } 3033 return false; 3034} 3035 3036//===----------------------------------------------------------------------===// 3037// CFG: Queries for BlkExprs. 3038//===----------------------------------------------------------------------===// 3039 3040namespace { 3041 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3042} 3043 3044static void FindSubExprAssignments(const Stmt *S, 3045 llvm::SmallPtrSet<const Expr*,50>& Set) { 3046 if (!S) 3047 return; 3048 3049 for (Stmt::const_child_range I = S->children(); I; ++I) { 3050 const Stmt *child = *I; 3051 if (!child) 3052 continue; 3053 3054 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3055 if (B->isAssignmentOp()) Set.insert(B); 3056 3057 FindSubExprAssignments(child, Set); 3058 } 3059} 3060 3061static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3062 BlkExprMapTy* M = new BlkExprMapTy(); 3063 3064 // Look for assignments that are used as subexpressions. These are the only 3065 // assignments that we want to *possibly* register as a block-level 3066 // expression. Basically, if an assignment occurs both in a subexpression and 3067 // at the block-level, it is a block-level expression. 3068 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3069 3070 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3071 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3072 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3073 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3074 3075 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3076 3077 // Iterate over the statements again on identify the Expr* and Stmt* at the 3078 // block-level that are block-level expressions. 3079 3080 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3081 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3082 if (!CS) 3083 continue; 3084 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3085 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3086 3087 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3088 // Assignment expressions that are not nested within another 3089 // expression are really "statements" whose value is never used by 3090 // another expression. 3091 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3092 continue; 3093 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3094 // Special handling for statement expressions. The last statement in 3095 // the statement expression is also a block-level expr. 3096 const CompoundStmt *C = SE->getSubStmt(); 3097 if (!C->body_empty()) { 3098 const Stmt *Last = C->body_back(); 3099 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3100 Last = LastEx->IgnoreParens(); 3101 unsigned x = M->size(); 3102 (*M)[Last] = x; 3103 } 3104 } 3105 3106 unsigned x = M->size(); 3107 (*M)[Exp] = x; 3108 } 3109 } 3110 3111 // Look at terminators. The condition is a block-level expression. 3112 3113 Stmt *S = (*I)->getTerminatorCondition(); 3114 3115 if (S && M->find(S) == M->end()) { 3116 unsigned x = M->size(); 3117 (*M)[S] = x; 3118 } 3119 } 3120 3121 return M; 3122} 3123 3124CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3125 assert(S != NULL); 3126 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3127 3128 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3129 BlkExprMapTy::iterator I = M->find(S); 3130 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3131} 3132 3133unsigned CFG::getNumBlkExprs() { 3134 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3135 return M->size(); 3136 3137 // We assume callers interested in the number of BlkExprs will want 3138 // the map constructed if it doesn't already exist. 3139 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3140 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3141} 3142 3143//===----------------------------------------------------------------------===// 3144// Filtered walking of the CFG. 3145//===----------------------------------------------------------------------===// 3146 3147bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3148 const CFGBlock *From, const CFGBlock *To) { 3149 3150 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3151 // If the 'To' has no label or is labeled but the label isn't a 3152 // CaseStmt then filter this edge. 3153 if (const SwitchStmt *S = 3154 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3155 if (S->isAllEnumCasesCovered()) { 3156 const Stmt *L = To->getLabel(); 3157 if (!L || !isa<CaseStmt>(L)) 3158 return true; 3159 } 3160 } 3161 } 3162 3163 return false; 3164} 3165 3166//===----------------------------------------------------------------------===// 3167// Cleanup: CFG dstor. 3168//===----------------------------------------------------------------------===// 3169 3170CFG::~CFG() { 3171 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3172} 3173 3174//===----------------------------------------------------------------------===// 3175// CFG pretty printing 3176//===----------------------------------------------------------------------===// 3177 3178namespace { 3179 3180class StmtPrinterHelper : public PrinterHelper { 3181 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3182 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3183 StmtMapTy StmtMap; 3184 DeclMapTy DeclMap; 3185 signed currentBlock; 3186 unsigned currentStmt; 3187 const LangOptions &LangOpts; 3188public: 3189 3190 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3191 : currentBlock(0), currentStmt(0), LangOpts(LO) 3192 { 3193 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3194 unsigned j = 1; 3195 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3196 BI != BEnd; ++BI, ++j ) { 3197 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3198 const Stmt *stmt= SE->getStmt(); 3199 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3200 StmtMap[stmt] = P; 3201 3202 switch (stmt->getStmtClass()) { 3203 case Stmt::DeclStmtClass: 3204 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3205 break; 3206 case Stmt::IfStmtClass: { 3207 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3208 if (var) 3209 DeclMap[var] = P; 3210 break; 3211 } 3212 case Stmt::ForStmtClass: { 3213 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3214 if (var) 3215 DeclMap[var] = P; 3216 break; 3217 } 3218 case Stmt::WhileStmtClass: { 3219 const VarDecl *var = 3220 cast<WhileStmt>(stmt)->getConditionVariable(); 3221 if (var) 3222 DeclMap[var] = P; 3223 break; 3224 } 3225 case Stmt::SwitchStmtClass: { 3226 const VarDecl *var = 3227 cast<SwitchStmt>(stmt)->getConditionVariable(); 3228 if (var) 3229 DeclMap[var] = P; 3230 break; 3231 } 3232 case Stmt::CXXCatchStmtClass: { 3233 const VarDecl *var = 3234 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3235 if (var) 3236 DeclMap[var] = P; 3237 break; 3238 } 3239 default: 3240 break; 3241 } 3242 } 3243 } 3244 } 3245 } 3246 3247 3248 virtual ~StmtPrinterHelper() {} 3249 3250 const LangOptions &getLangOpts() const { return LangOpts; } 3251 void setBlockID(signed i) { currentBlock = i; } 3252 void setStmtID(unsigned i) { currentStmt = i; } 3253 3254 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3255 StmtMapTy::iterator I = StmtMap.find(S); 3256 3257 if (I == StmtMap.end()) 3258 return false; 3259 3260 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3261 && I->second.second == currentStmt) { 3262 return false; 3263 } 3264 3265 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3266 return true; 3267 } 3268 3269 bool handleDecl(const Decl *D, raw_ostream &OS) { 3270 DeclMapTy::iterator I = DeclMap.find(D); 3271 3272 if (I == DeclMap.end()) 3273 return false; 3274 3275 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3276 && I->second.second == currentStmt) { 3277 return false; 3278 } 3279 3280 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3281 return true; 3282 } 3283}; 3284} // end anonymous namespace 3285 3286 3287namespace { 3288class CFGBlockTerminatorPrint 3289 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3290 3291 raw_ostream &OS; 3292 StmtPrinterHelper* Helper; 3293 PrintingPolicy Policy; 3294public: 3295 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3296 const PrintingPolicy &Policy) 3297 : OS(os), Helper(helper), Policy(Policy) {} 3298 3299 void VisitIfStmt(IfStmt *I) { 3300 OS << "if "; 3301 I->getCond()->printPretty(OS,Helper,Policy); 3302 } 3303 3304 // Default case. 3305 void VisitStmt(Stmt *Terminator) { 3306 Terminator->printPretty(OS, Helper, Policy); 3307 } 3308 3309 void VisitForStmt(ForStmt *F) { 3310 OS << "for (" ; 3311 if (F->getInit()) 3312 OS << "..."; 3313 OS << "; "; 3314 if (Stmt *C = F->getCond()) 3315 C->printPretty(OS, Helper, Policy); 3316 OS << "; "; 3317 if (F->getInc()) 3318 OS << "..."; 3319 OS << ")"; 3320 } 3321 3322 void VisitWhileStmt(WhileStmt *W) { 3323 OS << "while " ; 3324 if (Stmt *C = W->getCond()) 3325 C->printPretty(OS, Helper, Policy); 3326 } 3327 3328 void VisitDoStmt(DoStmt *D) { 3329 OS << "do ... while "; 3330 if (Stmt *C = D->getCond()) 3331 C->printPretty(OS, Helper, Policy); 3332 } 3333 3334 void VisitSwitchStmt(SwitchStmt *Terminator) { 3335 OS << "switch "; 3336 Terminator->getCond()->printPretty(OS, Helper, Policy); 3337 } 3338 3339 void VisitCXXTryStmt(CXXTryStmt *CS) { 3340 OS << "try ..."; 3341 } 3342 3343 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3344 C->getCond()->printPretty(OS, Helper, Policy); 3345 OS << " ? ... : ..."; 3346 } 3347 3348 void VisitChooseExpr(ChooseExpr *C) { 3349 OS << "__builtin_choose_expr( "; 3350 C->getCond()->printPretty(OS, Helper, Policy); 3351 OS << " )"; 3352 } 3353 3354 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3355 OS << "goto *"; 3356 I->getTarget()->printPretty(OS, Helper, Policy); 3357 } 3358 3359 void VisitBinaryOperator(BinaryOperator* B) { 3360 if (!B->isLogicalOp()) { 3361 VisitExpr(B); 3362 return; 3363 } 3364 3365 B->getLHS()->printPretty(OS, Helper, Policy); 3366 3367 switch (B->getOpcode()) { 3368 case BO_LOr: 3369 OS << " || ..."; 3370 return; 3371 case BO_LAnd: 3372 OS << " && ..."; 3373 return; 3374 default: 3375 assert(false && "Invalid logical operator."); 3376 } 3377 } 3378 3379 void VisitExpr(Expr *E) { 3380 E->printPretty(OS, Helper, Policy); 3381 } 3382}; 3383} // end anonymous namespace 3384 3385static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3386 const CFGElement &E) { 3387 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3388 const Stmt *S = CS->getStmt(); 3389 3390 if (Helper) { 3391 3392 // special printing for statement-expressions. 3393 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3394 const CompoundStmt *Sub = SE->getSubStmt(); 3395 3396 if (Sub->children()) { 3397 OS << "({ ... ; "; 3398 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3399 OS << " })\n"; 3400 return; 3401 } 3402 } 3403 // special printing for comma expressions. 3404 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3405 if (B->getOpcode() == BO_Comma) { 3406 OS << "... , "; 3407 Helper->handledStmt(B->getRHS(),OS); 3408 OS << '\n'; 3409 return; 3410 } 3411 } 3412 } 3413 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3414 3415 if (isa<CXXOperatorCallExpr>(S)) { 3416 OS << " (OperatorCall)"; 3417 } else if (isa<CXXBindTemporaryExpr>(S)) { 3418 OS << " (BindTemporary)"; 3419 } 3420 3421 // Expressions need a newline. 3422 if (isa<Expr>(S)) 3423 OS << '\n'; 3424 3425 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3426 const CXXCtorInitializer *I = IE->getInitializer(); 3427 if (I->isBaseInitializer()) 3428 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3429 else OS << I->getAnyMember()->getName(); 3430 3431 OS << "("; 3432 if (Expr *IE = I->getInit()) 3433 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3434 OS << ")"; 3435 3436 if (I->isBaseInitializer()) 3437 OS << " (Base initializer)\n"; 3438 else OS << " (Member initializer)\n"; 3439 3440 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3441 const VarDecl *VD = DE->getVarDecl(); 3442 Helper->handleDecl(VD, OS); 3443 3444 const Type* T = VD->getType().getTypePtr(); 3445 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3446 T = RT->getPointeeType().getTypePtr(); 3447 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3448 T = ET; 3449 3450 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3451 OS << " (Implicit destructor)\n"; 3452 3453 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3454 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3455 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3456 OS << " (Base object destructor)\n"; 3457 3458 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3459 const FieldDecl *FD = ME->getFieldDecl(); 3460 3461 const Type *T = FD->getType().getTypePtr(); 3462 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3463 T = ET; 3464 3465 OS << "this->" << FD->getName(); 3466 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3467 OS << " (Member object destructor)\n"; 3468 3469 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3470 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3471 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3472 OS << " (Temporary object destructor)\n"; 3473 } 3474} 3475 3476static void print_block(raw_ostream &OS, const CFG* cfg, 3477 const CFGBlock &B, 3478 StmtPrinterHelper* Helper, bool print_edges) { 3479 3480 if (Helper) Helper->setBlockID(B.getBlockID()); 3481 3482 // Print the header. 3483 OS << "\n [ B" << B.getBlockID(); 3484 3485 if (&B == &cfg->getEntry()) 3486 OS << " (ENTRY) ]\n"; 3487 else if (&B == &cfg->getExit()) 3488 OS << " (EXIT) ]\n"; 3489 else if (&B == cfg->getIndirectGotoBlock()) 3490 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3491 else 3492 OS << " ]\n"; 3493 3494 // Print the label of this block. 3495 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3496 3497 if (print_edges) 3498 OS << " "; 3499 3500 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3501 OS << L->getName(); 3502 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3503 OS << "case "; 3504 C->getLHS()->printPretty(OS, Helper, 3505 PrintingPolicy(Helper->getLangOpts())); 3506 if (C->getRHS()) { 3507 OS << " ... "; 3508 C->getRHS()->printPretty(OS, Helper, 3509 PrintingPolicy(Helper->getLangOpts())); 3510 } 3511 } else if (isa<DefaultStmt>(Label)) 3512 OS << "default"; 3513 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3514 OS << "catch ("; 3515 if (CS->getExceptionDecl()) 3516 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3517 0); 3518 else 3519 OS << "..."; 3520 OS << ")"; 3521 3522 } else 3523 assert(false && "Invalid label statement in CFGBlock."); 3524 3525 OS << ":\n"; 3526 } 3527 3528 // Iterate through the statements in the block and print them. 3529 unsigned j = 1; 3530 3531 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3532 I != E ; ++I, ++j ) { 3533 3534 // Print the statement # in the basic block and the statement itself. 3535 if (print_edges) 3536 OS << " "; 3537 3538 OS << llvm::format("%3d", j) << ": "; 3539 3540 if (Helper) 3541 Helper->setStmtID(j); 3542 3543 print_elem(OS,Helper,*I); 3544 } 3545 3546 // Print the terminator of this block. 3547 if (B.getTerminator()) { 3548 if (print_edges) 3549 OS << " "; 3550 3551 OS << " T: "; 3552 3553 if (Helper) Helper->setBlockID(-1); 3554 3555 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3556 PrintingPolicy(Helper->getLangOpts())); 3557 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3558 OS << '\n'; 3559 } 3560 3561 if (print_edges) { 3562 // Print the predecessors of this block. 3563 OS << " Predecessors (" << B.pred_size() << "):"; 3564 unsigned i = 0; 3565 3566 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3567 I != E; ++I, ++i) { 3568 3569 if (i == 8 || (i-8) == 0) 3570 OS << "\n "; 3571 3572 OS << " B" << (*I)->getBlockID(); 3573 } 3574 3575 OS << '\n'; 3576 3577 // Print the successors of this block. 3578 OS << " Successors (" << B.succ_size() << "):"; 3579 i = 0; 3580 3581 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3582 I != E; ++I, ++i) { 3583 3584 if (i == 8 || (i-8) % 10 == 0) 3585 OS << "\n "; 3586 3587 if (*I) 3588 OS << " B" << (*I)->getBlockID(); 3589 else 3590 OS << " NULL"; 3591 } 3592 3593 OS << '\n'; 3594 } 3595} 3596 3597 3598/// dump - A simple pretty printer of a CFG that outputs to stderr. 3599void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3600 3601/// print - A simple pretty printer of a CFG that outputs to an ostream. 3602void CFG::print(raw_ostream &OS, const LangOptions &LO) const { 3603 StmtPrinterHelper Helper(this, LO); 3604 3605 // Print the entry block. 3606 print_block(OS, this, getEntry(), &Helper, true); 3607 3608 // Iterate through the CFGBlocks and print them one by one. 3609 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3610 // Skip the entry block, because we already printed it. 3611 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3612 continue; 3613 3614 print_block(OS, this, **I, &Helper, true); 3615 } 3616 3617 // Print the exit block. 3618 print_block(OS, this, getExit(), &Helper, true); 3619 OS.flush(); 3620} 3621 3622/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3623void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3624 print(llvm::errs(), cfg, LO); 3625} 3626 3627/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3628/// Generally this will only be called from CFG::print. 3629void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3630 const LangOptions &LO) const { 3631 StmtPrinterHelper Helper(cfg, LO); 3632 print_block(OS, cfg, *this, &Helper, true); 3633} 3634 3635/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3636void CFGBlock::printTerminator(raw_ostream &OS, 3637 const LangOptions &LO) const { 3638 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3639 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3640} 3641 3642Stmt *CFGBlock::getTerminatorCondition() { 3643 Stmt *Terminator = this->Terminator; 3644 if (!Terminator) 3645 return NULL; 3646 3647 Expr *E = NULL; 3648 3649 switch (Terminator->getStmtClass()) { 3650 default: 3651 break; 3652 3653 case Stmt::ForStmtClass: 3654 E = cast<ForStmt>(Terminator)->getCond(); 3655 break; 3656 3657 case Stmt::WhileStmtClass: 3658 E = cast<WhileStmt>(Terminator)->getCond(); 3659 break; 3660 3661 case Stmt::DoStmtClass: 3662 E = cast<DoStmt>(Terminator)->getCond(); 3663 break; 3664 3665 case Stmt::IfStmtClass: 3666 E = cast<IfStmt>(Terminator)->getCond(); 3667 break; 3668 3669 case Stmt::ChooseExprClass: 3670 E = cast<ChooseExpr>(Terminator)->getCond(); 3671 break; 3672 3673 case Stmt::IndirectGotoStmtClass: 3674 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3675 break; 3676 3677 case Stmt::SwitchStmtClass: 3678 E = cast<SwitchStmt>(Terminator)->getCond(); 3679 break; 3680 3681 case Stmt::BinaryConditionalOperatorClass: 3682 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3683 break; 3684 3685 case Stmt::ConditionalOperatorClass: 3686 E = cast<ConditionalOperator>(Terminator)->getCond(); 3687 break; 3688 3689 case Stmt::BinaryOperatorClass: // '&&' and '||' 3690 E = cast<BinaryOperator>(Terminator)->getLHS(); 3691 break; 3692 3693 case Stmt::ObjCForCollectionStmtClass: 3694 return Terminator; 3695 } 3696 3697 return E ? E->IgnoreParens() : NULL; 3698} 3699 3700//===----------------------------------------------------------------------===// 3701// CFG Graphviz Visualization 3702//===----------------------------------------------------------------------===// 3703 3704 3705#ifndef NDEBUG 3706static StmtPrinterHelper* GraphHelper; 3707#endif 3708 3709void CFG::viewCFG(const LangOptions &LO) const { 3710#ifndef NDEBUG 3711 StmtPrinterHelper H(this, LO); 3712 GraphHelper = &H; 3713 llvm::ViewGraph(this,"CFG"); 3714 GraphHelper = NULL; 3715#endif 3716} 3717 3718namespace llvm { 3719template<> 3720struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3721 3722 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3723 3724 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 3725 3726#ifndef NDEBUG 3727 std::string OutSStr; 3728 llvm::raw_string_ostream Out(OutSStr); 3729 print_block(Out,Graph, *Node, GraphHelper, false); 3730 std::string& OutStr = Out.str(); 3731 3732 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3733 3734 // Process string output to make it nicer... 3735 for (unsigned i = 0; i != OutStr.length(); ++i) 3736 if (OutStr[i] == '\n') { // Left justify 3737 OutStr[i] = '\\'; 3738 OutStr.insert(OutStr.begin()+i+1, 'l'); 3739 } 3740 3741 return OutStr; 3742#else 3743 return ""; 3744#endif 3745 } 3746}; 3747} // end namespace llvm 3748