CFG.cpp revision 7154c03b366c4a6d83c086b624af269f779eb7b0
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "clang/AST/CharUnits.h" 21#include "llvm/Support/GraphWriter.h" 22#include "llvm/Support/Allocator.h" 23#include "llvm/Support/Format.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/OwningPtr.h" 27 28using namespace clang; 29 30namespace { 31 32static SourceLocation GetEndLoc(Decl *D) { 33 if (VarDecl *VD = dyn_cast<VarDecl>(D)) 34 if (Expr *Ex = VD->getInit()) 35 return Ex->getSourceRange().getEnd(); 36 return D->getLocation(); 37} 38 39class CFGBuilder; 40 41/// The CFG builder uses a recursive algorithm to build the CFG. When 42/// we process an expression, sometimes we know that we must add the 43/// subexpressions as block-level expressions. For example: 44/// 45/// exp1 || exp2 46/// 47/// When processing the '||' expression, we know that exp1 and exp2 48/// need to be added as block-level expressions, even though they 49/// might not normally need to be. AddStmtChoice records this 50/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 51/// the builder has an option not to add a subexpression as a 52/// block-level expression. 53/// 54class AddStmtChoice { 55public: 56 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 57 58 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 59 60 bool alwaysAdd(CFGBuilder &builder, 61 const Stmt *stmt) const; 62 63 /// Return a copy of this object, except with the 'always-add' bit 64 /// set as specified. 65 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 66 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 67 } 68 69private: 70 Kind kind; 71}; 72 73/// LocalScope - Node in tree of local scopes created for C++ implicit 74/// destructor calls generation. It contains list of automatic variables 75/// declared in the scope and link to position in previous scope this scope 76/// began in. 77/// 78/// The process of creating local scopes is as follows: 79/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 80/// - Before processing statements in scope (e.g. CompoundStmt) create 81/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 82/// and set CFGBuilder::ScopePos to the end of new scope, 83/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 84/// at this VarDecl, 85/// - For every normal (without jump) end of scope add to CFGBlock destructors 86/// for objects in the current scope, 87/// - For every jump add to CFGBlock destructors for objects 88/// between CFGBuilder::ScopePos and local scope position saved for jump 89/// target. Thanks to C++ restrictions on goto jumps we can be sure that 90/// jump target position will be on the path to root from CFGBuilder::ScopePos 91/// (adding any variable that doesn't need constructor to be called to 92/// LocalScope can break this assumption), 93/// 94class LocalScope { 95public: 96 typedef BumpVector<VarDecl*> AutomaticVarsTy; 97 98 /// const_iterator - Iterates local scope backwards and jumps to previous 99 /// scope on reaching the beginning of currently iterated scope. 100 class const_iterator { 101 const LocalScope* Scope; 102 103 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 104 /// Invalid iterator (with null Scope) has VarIter equal to 0. 105 unsigned VarIter; 106 107 public: 108 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 109 /// Incrementing invalid iterator is allowed and will result in invalid 110 /// iterator. 111 const_iterator() 112 : Scope(NULL), VarIter(0) {} 113 114 /// Create valid iterator. In case when S.Prev is an invalid iterator and 115 /// I is equal to 0, this will create invalid iterator. 116 const_iterator(const LocalScope& S, unsigned I) 117 : Scope(&S), VarIter(I) { 118 // Iterator to "end" of scope is not allowed. Handle it by going up 119 // in scopes tree possibly up to invalid iterator in the root. 120 if (VarIter == 0 && Scope) 121 *this = Scope->Prev; 122 } 123 124 VarDecl *const* operator->() const { 125 assert (Scope && "Dereferencing invalid iterator is not allowed"); 126 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 127 return &Scope->Vars[VarIter - 1]; 128 } 129 VarDecl *operator*() const { 130 return *this->operator->(); 131 } 132 133 const_iterator &operator++() { 134 if (!Scope) 135 return *this; 136 137 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 138 --VarIter; 139 if (VarIter == 0) 140 *this = Scope->Prev; 141 return *this; 142 } 143 const_iterator operator++(int) { 144 const_iterator P = *this; 145 ++*this; 146 return P; 147 } 148 149 bool operator==(const const_iterator &rhs) const { 150 return Scope == rhs.Scope && VarIter == rhs.VarIter; 151 } 152 bool operator!=(const const_iterator &rhs) const { 153 return !(*this == rhs); 154 } 155 156 operator bool() const { 157 return *this != const_iterator(); 158 } 159 160 int distance(const_iterator L); 161 }; 162 163 friend class const_iterator; 164 165private: 166 BumpVectorContext ctx; 167 168 /// Automatic variables in order of declaration. 169 AutomaticVarsTy Vars; 170 /// Iterator to variable in previous scope that was declared just before 171 /// begin of this scope. 172 const_iterator Prev; 173 174public: 175 /// Constructs empty scope linked to previous scope in specified place. 176 LocalScope(BumpVectorContext &ctx, const_iterator P) 177 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 178 179 /// Begin of scope in direction of CFG building (backwards). 180 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 181 182 void addVar(VarDecl *VD) { 183 Vars.push_back(VD, ctx); 184 } 185}; 186 187/// distance - Calculates distance from this to L. L must be reachable from this 188/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 189/// number of scopes between this and L. 190int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 191 int D = 0; 192 const_iterator F = *this; 193 while (F.Scope != L.Scope) { 194 assert (F != const_iterator() 195 && "L iterator is not reachable from F iterator."); 196 D += F.VarIter; 197 F = F.Scope->Prev; 198 } 199 D += F.VarIter - L.VarIter; 200 return D; 201} 202 203/// BlockScopePosPair - Structure for specifying position in CFG during its 204/// build process. It consists of CFGBlock that specifies position in CFG graph 205/// and LocalScope::const_iterator that specifies position in LocalScope graph. 206struct BlockScopePosPair { 207 BlockScopePosPair() : block(0) {} 208 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos) 209 : block(b), scopePosition(scopePos) {} 210 211 CFGBlock *block; 212 LocalScope::const_iterator scopePosition; 213}; 214 215/// TryResult - a class representing a variant over the values 216/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 217/// and is used by the CFGBuilder to decide if a branch condition 218/// can be decided up front during CFG construction. 219class TryResult { 220 int X; 221public: 222 TryResult(bool b) : X(b ? 1 : 0) {} 223 TryResult() : X(-1) {} 224 225 bool isTrue() const { return X == 1; } 226 bool isFalse() const { return X == 0; } 227 bool isKnown() const { return X >= 0; } 228 void negate() { 229 assert(isKnown()); 230 X ^= 0x1; 231 } 232}; 233 234/// CFGBuilder - This class implements CFG construction from an AST. 235/// The builder is stateful: an instance of the builder should be used to only 236/// construct a single CFG. 237/// 238/// Example usage: 239/// 240/// CFGBuilder builder; 241/// CFG* cfg = builder.BuildAST(stmt1); 242/// 243/// CFG construction is done via a recursive walk of an AST. We actually parse 244/// the AST in reverse order so that the successor of a basic block is 245/// constructed prior to its predecessor. This allows us to nicely capture 246/// implicit fall-throughs without extra basic blocks. 247/// 248class CFGBuilder { 249 typedef BlockScopePosPair JumpTarget; 250 typedef BlockScopePosPair JumpSource; 251 252 ASTContext *Context; 253 llvm::OwningPtr<CFG> cfg; 254 255 CFGBlock *Block; 256 CFGBlock *Succ; 257 JumpTarget ContinueJumpTarget; 258 JumpTarget BreakJumpTarget; 259 CFGBlock *SwitchTerminatedBlock; 260 CFGBlock *DefaultCaseBlock; 261 CFGBlock *TryTerminatedBlock; 262 263 // Current position in local scope. 264 LocalScope::const_iterator ScopePos; 265 266 // LabelMap records the mapping from Label expressions to their jump targets. 267 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 268 LabelMapTy LabelMap; 269 270 // A list of blocks that end with a "goto" that must be backpatched to their 271 // resolved targets upon completion of CFG construction. 272 typedef std::vector<JumpSource> BackpatchBlocksTy; 273 BackpatchBlocksTy BackpatchBlocks; 274 275 // A list of labels whose address has been taken (for indirect gotos). 276 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 277 LabelSetTy AddressTakenLabels; 278 279 bool badCFG; 280 const CFG::BuildOptions &BuildOpts; 281 282 // State to track for building switch statements. 283 bool switchExclusivelyCovered; 284 Expr::EvalResult *switchCond; 285 286 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 287 const Stmt *lastLookup; 288 289public: 290 explicit CFGBuilder(ASTContext *astContext, 291 const CFG::BuildOptions &buildOpts) 292 : Context(astContext), cfg(new CFG()), // crew a new CFG 293 Block(NULL), Succ(NULL), 294 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 295 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 296 switchExclusivelyCovered(false), switchCond(0), 297 cachedEntry(0), lastLookup(0) {} 298 299 // buildCFG - Used by external clients to construct the CFG. 300 CFG* buildCFG(const Decl *D, Stmt *Statement); 301 302 bool alwaysAdd(const Stmt *stmt); 303 304private: 305 // Visitors to walk an AST and construct the CFG. 306 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 307 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 308 CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc); 309 CFGBlock *VisitBreakStmt(BreakStmt *B); 310 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 311 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 312 AddStmtChoice asc); 313 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 314 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 315 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 316 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 317 AddStmtChoice asc); 318 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 319 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 320 AddStmtChoice asc); 321 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 322 AddStmtChoice asc); 323 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 324 CFGBlock *VisitCaseStmt(CaseStmt *C); 325 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 326 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 327 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 328 AddStmtChoice asc); 329 CFGBlock *VisitContinueStmt(ContinueStmt *C); 330 CFGBlock *VisitDeclStmt(DeclStmt *DS); 331 CFGBlock *VisitDeclSubExpr(DeclStmt *DS); 332 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 333 CFGBlock *VisitDoStmt(DoStmt *D); 334 CFGBlock *VisitForStmt(ForStmt *F); 335 CFGBlock *VisitGotoStmt(GotoStmt *G); 336 CFGBlock *VisitIfStmt(IfStmt *I); 337 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 338 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 339 CFGBlock *VisitLabelStmt(LabelStmt *L); 340 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 341 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 342 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 343 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 344 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 345 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 346 CFGBlock *VisitReturnStmt(ReturnStmt *R); 347 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E); 348 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 349 AddStmtChoice asc); 350 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 351 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 352 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 353 CFGBlock *VisitWhileStmt(WhileStmt *W); 354 355 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 356 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 357 CFGBlock *VisitChildren(Stmt *S); 358 359 // Visitors to walk an AST and generate destructors of temporaries in 360 // full expression. 361 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 362 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 363 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 364 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 365 bool BindToTemporary); 366 CFGBlock * 367 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 368 bool BindToTemporary); 369 370 // NYS == Not Yet Supported 371 CFGBlock *NYS() { 372 badCFG = true; 373 return Block; 374 } 375 376 void autoCreateBlock() { if (!Block) Block = createBlock(); } 377 CFGBlock *createBlock(bool add_successor = true); 378 CFGBlock *createNoReturnBlock(); 379 380 CFGBlock *addStmt(Stmt *S) { 381 return Visit(S, AddStmtChoice::AlwaysAdd); 382 } 383 CFGBlock *addInitializer(CXXCtorInitializer *I); 384 void addAutomaticObjDtors(LocalScope::const_iterator B, 385 LocalScope::const_iterator E, Stmt *S); 386 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 387 388 // Local scopes creation. 389 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 390 391 void addLocalScopeForStmt(Stmt *S); 392 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 393 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 394 395 void addLocalScopeAndDtors(Stmt *S); 396 397 // Interface to CFGBlock - adding CFGElements. 398 void appendStmt(CFGBlock *B, const Stmt *S) { 399 if (alwaysAdd(S) && cachedEntry) 400 cachedEntry->second = B; 401 402 // All block-level expressions should have already been IgnoreParens()ed. 403 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 404 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 405 } 406 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 407 B->appendInitializer(I, cfg->getBumpVectorContext()); 408 } 409 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 410 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 411 } 412 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 413 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 414 } 415 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 416 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 417 } 418 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 419 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 420 } 421 422 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 423 LocalScope::const_iterator B, LocalScope::const_iterator E); 424 425 void addSuccessor(CFGBlock *B, CFGBlock *S) { 426 B->addSuccessor(S, cfg->getBumpVectorContext()); 427 } 428 429 /// Try and evaluate an expression to an integer constant. 430 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 431 if (!BuildOpts.PruneTriviallyFalseEdges) 432 return false; 433 return !S->isTypeDependent() && 434 !S->isValueDependent() && 435 S->EvaluateAsRValue(outResult, *Context); 436 } 437 438 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 439 /// if we can evaluate to a known value, otherwise return -1. 440 TryResult tryEvaluateBool(Expr *S) { 441 bool Result; 442 if (!BuildOpts.PruneTriviallyFalseEdges || 443 S->isTypeDependent() || S->isValueDependent() || 444 !S->EvaluateAsBooleanCondition(Result, *Context)) 445 return TryResult(); 446 return Result; 447 } 448 449}; 450 451inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 452 const Stmt *stmt) const { 453 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 454} 455 456bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 457 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 458 459 if (!BuildOpts.forcedBlkExprs) 460 return shouldAdd; 461 462 if (lastLookup == stmt) { 463 if (cachedEntry) { 464 assert(cachedEntry->first == stmt); 465 return true; 466 } 467 return shouldAdd; 468 } 469 470 lastLookup = stmt; 471 472 // Perform the lookup! 473 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 474 475 if (!fb) { 476 // No need to update 'cachedEntry', since it will always be null. 477 assert(cachedEntry == 0); 478 return shouldAdd; 479 } 480 481 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 482 if (itr == fb->end()) { 483 cachedEntry = 0; 484 return shouldAdd; 485 } 486 487 cachedEntry = &*itr; 488 return true; 489} 490 491// FIXME: Add support for dependent-sized array types in C++? 492// Does it even make sense to build a CFG for an uninstantiated template? 493static const VariableArrayType *FindVA(const Type *t) { 494 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 495 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 496 if (vat->getSizeExpr()) 497 return vat; 498 499 t = vt->getElementType().getTypePtr(); 500 } 501 502 return 0; 503} 504 505/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 506/// arbitrary statement. Examples include a single expression or a function 507/// body (compound statement). The ownership of the returned CFG is 508/// transferred to the caller. If CFG construction fails, this method returns 509/// NULL. 510CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 511 assert(cfg.get()); 512 if (!Statement) 513 return NULL; 514 515 // Create an empty block that will serve as the exit block for the CFG. Since 516 // this is the first block added to the CFG, it will be implicitly registered 517 // as the exit block. 518 Succ = createBlock(); 519 assert(Succ == &cfg->getExit()); 520 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 521 522 if (BuildOpts.AddImplicitDtors) 523 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 524 addImplicitDtorsForDestructor(DD); 525 526 // Visit the statements and create the CFG. 527 CFGBlock *B = addStmt(Statement); 528 529 if (badCFG) 530 return NULL; 531 532 // For C++ constructor add initializers to CFG. 533 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 534 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 535 E = CD->init_rend(); I != E; ++I) { 536 B = addInitializer(*I); 537 if (badCFG) 538 return NULL; 539 } 540 } 541 542 if (B) 543 Succ = B; 544 545 // Backpatch the gotos whose label -> block mappings we didn't know when we 546 // encountered them. 547 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 548 E = BackpatchBlocks.end(); I != E; ++I ) { 549 550 CFGBlock *B = I->block; 551 GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 552 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 553 554 // If there is no target for the goto, then we are looking at an 555 // incomplete AST. Handle this by not registering a successor. 556 if (LI == LabelMap.end()) continue; 557 558 JumpTarget JT = LI->second; 559 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 560 JT.scopePosition); 561 addSuccessor(B, JT.block); 562 } 563 564 // Add successors to the Indirect Goto Dispatch block (if we have one). 565 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 566 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 567 E = AddressTakenLabels.end(); I != E; ++I ) { 568 569 // Lookup the target block. 570 LabelMapTy::iterator LI = LabelMap.find(*I); 571 572 // If there is no target block that contains label, then we are looking 573 // at an incomplete AST. Handle this by not registering a successor. 574 if (LI == LabelMap.end()) continue; 575 576 addSuccessor(B, LI->second.block); 577 } 578 579 // Create an empty entry block that has no predecessors. 580 cfg->setEntry(createBlock()); 581 582 return cfg.take(); 583} 584 585/// createBlock - Used to lazily create blocks that are connected 586/// to the current (global) succcessor. 587CFGBlock *CFGBuilder::createBlock(bool add_successor) { 588 CFGBlock *B = cfg->createBlock(); 589 if (add_successor && Succ) 590 addSuccessor(B, Succ); 591 return B; 592} 593 594/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the 595/// CFG. It is *not* connected to the current (global) successor, and instead 596/// directly tied to the exit block in order to be reachable. 597CFGBlock *CFGBuilder::createNoReturnBlock() { 598 CFGBlock *B = createBlock(false); 599 B->setHasNoReturnElement(); 600 addSuccessor(B, &cfg->getExit()); 601 return B; 602} 603 604/// addInitializer - Add C++ base or member initializer element to CFG. 605CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 606 if (!BuildOpts.AddInitializers) 607 return Block; 608 609 bool IsReference = false; 610 bool HasTemporaries = false; 611 612 // Destructors of temporaries in initialization expression should be called 613 // after initialization finishes. 614 Expr *Init = I->getInit(); 615 if (Init) { 616 if (FieldDecl *FD = I->getAnyMember()) 617 IsReference = FD->getType()->isReferenceType(); 618 HasTemporaries = isa<ExprWithCleanups>(Init); 619 620 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 621 // Generate destructors for temporaries in initialization expression. 622 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 623 IsReference); 624 } 625 } 626 627 autoCreateBlock(); 628 appendInitializer(Block, I); 629 630 if (Init) { 631 if (HasTemporaries) { 632 // For expression with temporaries go directly to subexpression to omit 633 // generating destructors for the second time. 634 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 635 } 636 return Visit(Init); 637 } 638 639 return Block; 640} 641 642/// \brief Retrieve the type of the temporary object whose lifetime was 643/// extended by a local reference with the given initializer. 644static QualType getReferenceInitTemporaryType(ASTContext &Context, 645 const Expr *Init) { 646 while (true) { 647 // Skip parentheses. 648 Init = Init->IgnoreParens(); 649 650 // Skip through cleanups. 651 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) { 652 Init = EWC->getSubExpr(); 653 continue; 654 } 655 656 // Skip through the temporary-materialization expression. 657 if (const MaterializeTemporaryExpr *MTE 658 = dyn_cast<MaterializeTemporaryExpr>(Init)) { 659 Init = MTE->GetTemporaryExpr(); 660 continue; 661 } 662 663 // Skip derived-to-base and no-op casts. 664 if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) { 665 if ((CE->getCastKind() == CK_DerivedToBase || 666 CE->getCastKind() == CK_UncheckedDerivedToBase || 667 CE->getCastKind() == CK_NoOp) && 668 Init->getType()->isRecordType()) { 669 Init = CE->getSubExpr(); 670 continue; 671 } 672 } 673 674 // Skip member accesses into rvalues. 675 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) { 676 if (!ME->isArrow() && ME->getBase()->isRValue()) { 677 Init = ME->getBase(); 678 continue; 679 } 680 } 681 682 break; 683 } 684 685 return Init->getType(); 686} 687 688/// addAutomaticObjDtors - Add to current block automatic objects destructors 689/// for objects in range of local scope positions. Use S as trigger statement 690/// for destructors. 691void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 692 LocalScope::const_iterator E, Stmt *S) { 693 if (!BuildOpts.AddImplicitDtors) 694 return; 695 696 if (B == E) 697 return; 698 699 CFGBlock::iterator InsertPos; 700 701 // We need to append the destructors in reverse order, but any one of them 702 // may be a no-return destructor which changes the CFG. As a result, buffer 703 // this sequence up and replay them in reverse order when appending onto the 704 // CFGBlock(s). 705 SmallVector<VarDecl*, 10> Decls; 706 Decls.reserve(B.distance(E)); 707 for (LocalScope::const_iterator I = B; I != E; ++I) 708 Decls.push_back(*I); 709 710 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 711 E = Decls.rend(); 712 I != E; ++I) { 713 // If this destructor is marked as a no-return destructor, we need to 714 // create a new block for the destructor which does not have as a successor 715 // anything built thus far: control won't flow out of this block. 716 QualType Ty; 717 if ((*I)->getType()->isReferenceType()) { 718 Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit()); 719 } else { 720 Ty = Context->getBaseElementType((*I)->getType()); 721 } 722 723 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 724 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 725 Block = createNoReturnBlock(); 726 else 727 autoCreateBlock(); 728 729 appendAutomaticObjDtor(Block, *I, S); 730 } 731} 732 733/// addImplicitDtorsForDestructor - Add implicit destructors generated for 734/// base and member objects in destructor. 735void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 736 assert (BuildOpts.AddImplicitDtors 737 && "Can be called only when dtors should be added"); 738 const CXXRecordDecl *RD = DD->getParent(); 739 740 // At the end destroy virtual base objects. 741 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 742 VE = RD->vbases_end(); VI != VE; ++VI) { 743 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 744 if (!CD->hasTrivialDestructor()) { 745 autoCreateBlock(); 746 appendBaseDtor(Block, VI); 747 } 748 } 749 750 // Before virtual bases destroy direct base objects. 751 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 752 BE = RD->bases_end(); BI != BE; ++BI) { 753 if (!BI->isVirtual()) 754 if (const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl()) 755 if (!CD->hasTrivialDestructor()) { 756 autoCreateBlock(); 757 appendBaseDtor(Block, BI); 758 } 759 } 760 761 // First destroy member objects. 762 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 763 FE = RD->field_end(); FI != FE; ++FI) { 764 // Check for constant size array. Set type to array element type. 765 QualType QT = FI->getType(); 766 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 767 if (AT->getSize() == 0) 768 continue; 769 QT = AT->getElementType(); 770 } 771 772 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 773 if (!CD->hasTrivialDestructor()) { 774 autoCreateBlock(); 775 appendMemberDtor(Block, *FI); 776 } 777 } 778} 779 780/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 781/// way return valid LocalScope object. 782LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 783 if (!Scope) { 784 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 785 Scope = alloc.Allocate<LocalScope>(); 786 BumpVectorContext ctx(alloc); 787 new (Scope) LocalScope(ctx, ScopePos); 788 } 789 return Scope; 790} 791 792/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 793/// that should create implicit scope (e.g. if/else substatements). 794void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 795 if (!BuildOpts.AddImplicitDtors) 796 return; 797 798 LocalScope *Scope = 0; 799 800 // For compound statement we will be creating explicit scope. 801 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 802 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 803 ; BI != BE; ++BI) { 804 Stmt *SI = (*BI)->stripLabelLikeStatements(); 805 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 806 Scope = addLocalScopeForDeclStmt(DS, Scope); 807 } 808 return; 809 } 810 811 // For any other statement scope will be implicit and as such will be 812 // interesting only for DeclStmt. 813 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 814 addLocalScopeForDeclStmt(DS); 815} 816 817/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 818/// reuse Scope if not NULL. 819LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 820 LocalScope* Scope) { 821 if (!BuildOpts.AddImplicitDtors) 822 return Scope; 823 824 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 825 ; DI != DE; ++DI) { 826 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 827 Scope = addLocalScopeForVarDecl(VD, Scope); 828 } 829 return Scope; 830} 831 832/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 833/// create add scope for automatic objects and temporary objects bound to 834/// const reference. Will reuse Scope if not NULL. 835LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 836 LocalScope* Scope) { 837 if (!BuildOpts.AddImplicitDtors) 838 return Scope; 839 840 // Check if variable is local. 841 switch (VD->getStorageClass()) { 842 case SC_None: 843 case SC_Auto: 844 case SC_Register: 845 break; 846 default: return Scope; 847 } 848 849 // Check for const references bound to temporary. Set type to pointee. 850 QualType QT = VD->getType(); 851 if (QT.getTypePtr()->isReferenceType()) { 852 if (!VD->extendsLifetimeOfTemporary()) 853 return Scope; 854 855 QT = getReferenceInitTemporaryType(*Context, VD->getInit()); 856 } 857 858 // Check for constant size array. Set type to array element type. 859 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 860 if (AT->getSize() == 0) 861 return Scope; 862 QT = AT->getElementType(); 863 } 864 865 // Check if type is a C++ class with non-trivial destructor. 866 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 867 if (!CD->hasTrivialDestructor()) { 868 // Add the variable to scope 869 Scope = createOrReuseLocalScope(Scope); 870 Scope->addVar(VD); 871 ScopePos = Scope->begin(); 872 } 873 return Scope; 874} 875 876/// addLocalScopeAndDtors - For given statement add local scope for it and 877/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 878void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 879 if (!BuildOpts.AddImplicitDtors) 880 return; 881 882 LocalScope::const_iterator scopeBeginPos = ScopePos; 883 addLocalScopeForStmt(S); 884 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 885} 886 887/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 888/// variables with automatic storage duration to CFGBlock's elements vector. 889/// Elements will be prepended to physical beginning of the vector which 890/// happens to be logical end. Use blocks terminator as statement that specifies 891/// destructors call site. 892/// FIXME: This mechanism for adding automatic destructors doesn't handle 893/// no-return destructors properly. 894void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 895 LocalScope::const_iterator B, LocalScope::const_iterator E) { 896 BumpVectorContext &C = cfg->getBumpVectorContext(); 897 CFGBlock::iterator InsertPos 898 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 899 for (LocalScope::const_iterator I = B; I != E; ++I) 900 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 901 Blk->getTerminator()); 902} 903 904/// Visit - Walk the subtree of a statement and add extra 905/// blocks for ternary operators, &&, and ||. We also process "," and 906/// DeclStmts (which may contain nested control-flow). 907CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 908 if (!S) { 909 badCFG = true; 910 return 0; 911 } 912 913 if (Expr *E = dyn_cast<Expr>(S)) 914 S = E->IgnoreParens(); 915 916 switch (S->getStmtClass()) { 917 default: 918 return VisitStmt(S, asc); 919 920 case Stmt::AddrLabelExprClass: 921 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 922 923 case Stmt::BinaryConditionalOperatorClass: 924 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 925 926 case Stmt::BinaryOperatorClass: 927 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 928 929 case Stmt::BlockExprClass: 930 return VisitBlockExpr(cast<BlockExpr>(S), asc); 931 932 case Stmt::BreakStmtClass: 933 return VisitBreakStmt(cast<BreakStmt>(S)); 934 935 case Stmt::CallExprClass: 936 case Stmt::CXXOperatorCallExprClass: 937 case Stmt::CXXMemberCallExprClass: 938 return VisitCallExpr(cast<CallExpr>(S), asc); 939 940 case Stmt::CaseStmtClass: 941 return VisitCaseStmt(cast<CaseStmt>(S)); 942 943 case Stmt::ChooseExprClass: 944 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 945 946 case Stmt::CompoundStmtClass: 947 return VisitCompoundStmt(cast<CompoundStmt>(S)); 948 949 case Stmt::ConditionalOperatorClass: 950 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 951 952 case Stmt::ContinueStmtClass: 953 return VisitContinueStmt(cast<ContinueStmt>(S)); 954 955 case Stmt::CXXCatchStmtClass: 956 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 957 958 case Stmt::ExprWithCleanupsClass: 959 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 960 961 case Stmt::CXXBindTemporaryExprClass: 962 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 963 964 case Stmt::CXXConstructExprClass: 965 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 966 967 case Stmt::CXXFunctionalCastExprClass: 968 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 969 970 case Stmt::CXXTemporaryObjectExprClass: 971 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 972 973 case Stmt::CXXThrowExprClass: 974 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 975 976 case Stmt::CXXTryStmtClass: 977 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 978 979 case Stmt::CXXForRangeStmtClass: 980 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 981 982 case Stmt::DeclStmtClass: 983 return VisitDeclStmt(cast<DeclStmt>(S)); 984 985 case Stmt::DefaultStmtClass: 986 return VisitDefaultStmt(cast<DefaultStmt>(S)); 987 988 case Stmt::DoStmtClass: 989 return VisitDoStmt(cast<DoStmt>(S)); 990 991 case Stmt::ForStmtClass: 992 return VisitForStmt(cast<ForStmt>(S)); 993 994 case Stmt::GotoStmtClass: 995 return VisitGotoStmt(cast<GotoStmt>(S)); 996 997 case Stmt::IfStmtClass: 998 return VisitIfStmt(cast<IfStmt>(S)); 999 1000 case Stmt::ImplicitCastExprClass: 1001 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 1002 1003 case Stmt::IndirectGotoStmtClass: 1004 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 1005 1006 case Stmt::LabelStmtClass: 1007 return VisitLabelStmt(cast<LabelStmt>(S)); 1008 1009 case Stmt::MemberExprClass: 1010 return VisitMemberExpr(cast<MemberExpr>(S), asc); 1011 1012 case Stmt::NullStmtClass: 1013 return Block; 1014 1015 case Stmt::ObjCAtCatchStmtClass: 1016 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 1017 1018 case Stmt::ObjCAtSynchronizedStmtClass: 1019 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 1020 1021 case Stmt::ObjCAtThrowStmtClass: 1022 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 1023 1024 case Stmt::ObjCAtTryStmtClass: 1025 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 1026 1027 case Stmt::ObjCForCollectionStmtClass: 1028 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 1029 1030 case Stmt::OpaqueValueExprClass: 1031 return Block; 1032 1033 case Stmt::PseudoObjectExprClass: 1034 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S)); 1035 1036 case Stmt::ReturnStmtClass: 1037 return VisitReturnStmt(cast<ReturnStmt>(S)); 1038 1039 case Stmt::UnaryExprOrTypeTraitExprClass: 1040 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 1041 asc); 1042 1043 case Stmt::StmtExprClass: 1044 return VisitStmtExpr(cast<StmtExpr>(S), asc); 1045 1046 case Stmt::SwitchStmtClass: 1047 return VisitSwitchStmt(cast<SwitchStmt>(S)); 1048 1049 case Stmt::UnaryOperatorClass: 1050 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 1051 1052 case Stmt::WhileStmtClass: 1053 return VisitWhileStmt(cast<WhileStmt>(S)); 1054 } 1055} 1056 1057CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1058 if (asc.alwaysAdd(*this, S)) { 1059 autoCreateBlock(); 1060 appendStmt(Block, S); 1061 } 1062 1063 return VisitChildren(S); 1064} 1065 1066/// VisitChildren - Visit the children of a Stmt. 1067CFGBlock *CFGBuilder::VisitChildren(Stmt *Terminator) { 1068 CFGBlock *lastBlock = Block; 1069 for (Stmt::child_range I = Terminator->children(); I; ++I) 1070 if (Stmt *child = *I) 1071 if (CFGBlock *b = Visit(child)) 1072 lastBlock = b; 1073 1074 return lastBlock; 1075} 1076 1077CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1078 AddStmtChoice asc) { 1079 AddressTakenLabels.insert(A->getLabel()); 1080 1081 if (asc.alwaysAdd(*this, A)) { 1082 autoCreateBlock(); 1083 appendStmt(Block, A); 1084 } 1085 1086 return Block; 1087} 1088 1089CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1090 AddStmtChoice asc) { 1091 if (asc.alwaysAdd(*this, U)) { 1092 autoCreateBlock(); 1093 appendStmt(Block, U); 1094 } 1095 1096 return Visit(U->getSubExpr(), AddStmtChoice()); 1097} 1098 1099CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1100 AddStmtChoice asc) { 1101 if (B->isLogicalOp()) { // && or || 1102 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1103 appendStmt(ConfluenceBlock, B); 1104 1105 if (badCFG) 1106 return 0; 1107 1108 // create the block evaluating the LHS 1109 CFGBlock *LHSBlock = createBlock(false); 1110 LHSBlock->setTerminator(B); 1111 1112 // create the block evaluating the RHS 1113 Succ = ConfluenceBlock; 1114 Block = NULL; 1115 CFGBlock *RHSBlock = addStmt(B->getRHS()); 1116 1117 if (RHSBlock) { 1118 if (badCFG) 1119 return 0; 1120 } else { 1121 // Create an empty block for cases where the RHS doesn't require 1122 // any explicit statements in the CFG. 1123 RHSBlock = createBlock(); 1124 } 1125 1126 // See if this is a known constant. 1127 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1128 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1129 KnownVal.negate(); 1130 1131 // Now link the LHSBlock with RHSBlock. 1132 if (B->getOpcode() == BO_LOr) { 1133 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1134 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1135 } else { 1136 assert(B->getOpcode() == BO_LAnd); 1137 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1138 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1139 } 1140 1141 // Generate the blocks for evaluating the LHS. 1142 Block = LHSBlock; 1143 return addStmt(B->getLHS()); 1144 } 1145 1146 if (B->getOpcode() == BO_Comma) { // , 1147 autoCreateBlock(); 1148 appendStmt(Block, B); 1149 addStmt(B->getRHS()); 1150 return addStmt(B->getLHS()); 1151 } 1152 1153 if (B->isAssignmentOp()) { 1154 if (asc.alwaysAdd(*this, B)) { 1155 autoCreateBlock(); 1156 appendStmt(Block, B); 1157 } 1158 Visit(B->getLHS()); 1159 return Visit(B->getRHS()); 1160 } 1161 1162 if (asc.alwaysAdd(*this, B)) { 1163 autoCreateBlock(); 1164 appendStmt(Block, B); 1165 } 1166 1167 CFGBlock *RBlock = Visit(B->getRHS()); 1168 CFGBlock *LBlock = Visit(B->getLHS()); 1169 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1170 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1171 // return RBlock. Otherwise we'll incorrectly return NULL. 1172 return (LBlock ? LBlock : RBlock); 1173} 1174 1175CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1176 if (asc.alwaysAdd(*this, E)) { 1177 autoCreateBlock(); 1178 appendStmt(Block, E); 1179 } 1180 return Block; 1181} 1182 1183CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1184 // "break" is a control-flow statement. Thus we stop processing the current 1185 // block. 1186 if (badCFG) 1187 return 0; 1188 1189 // Now create a new block that ends with the break statement. 1190 Block = createBlock(false); 1191 Block->setTerminator(B); 1192 1193 // If there is no target for the break, then we are looking at an incomplete 1194 // AST. This means that the CFG cannot be constructed. 1195 if (BreakJumpTarget.block) { 1196 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1197 addSuccessor(Block, BreakJumpTarget.block); 1198 } else 1199 badCFG = true; 1200 1201 1202 return Block; 1203} 1204 1205static bool CanThrow(Expr *E, ASTContext &Ctx) { 1206 QualType Ty = E->getType(); 1207 if (Ty->isFunctionPointerType()) 1208 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1209 else if (Ty->isBlockPointerType()) 1210 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1211 1212 const FunctionType *FT = Ty->getAs<FunctionType>(); 1213 if (FT) { 1214 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1215 if (Proto->isNothrow(Ctx)) 1216 return false; 1217 } 1218 return true; 1219} 1220 1221CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1222 // Compute the callee type. 1223 QualType calleeType = C->getCallee()->getType(); 1224 if (calleeType == Context->BoundMemberTy) { 1225 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1226 1227 // We should only get a null bound type if processing a dependent 1228 // CFG. Recover by assuming nothing. 1229 if (!boundType.isNull()) calleeType = boundType; 1230 } 1231 1232 // If this is a call to a no-return function, this stops the block here. 1233 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1234 1235 bool AddEHEdge = false; 1236 1237 // Languages without exceptions are assumed to not throw. 1238 if (Context->getLangOptions().Exceptions) { 1239 if (BuildOpts.AddEHEdges) 1240 AddEHEdge = true; 1241 } 1242 1243 if (FunctionDecl *FD = C->getDirectCallee()) { 1244 if (FD->hasAttr<NoReturnAttr>()) 1245 NoReturn = true; 1246 if (FD->hasAttr<NoThrowAttr>()) 1247 AddEHEdge = false; 1248 } 1249 1250 if (!CanThrow(C->getCallee(), *Context)) 1251 AddEHEdge = false; 1252 1253 if (!NoReturn && !AddEHEdge) 1254 return VisitStmt(C, asc.withAlwaysAdd(true)); 1255 1256 if (Block) { 1257 Succ = Block; 1258 if (badCFG) 1259 return 0; 1260 } 1261 1262 if (NoReturn) 1263 Block = createNoReturnBlock(); 1264 else 1265 Block = createBlock(); 1266 1267 appendStmt(Block, C); 1268 1269 if (AddEHEdge) { 1270 // Add exceptional edges. 1271 if (TryTerminatedBlock) 1272 addSuccessor(Block, TryTerminatedBlock); 1273 else 1274 addSuccessor(Block, &cfg->getExit()); 1275 } 1276 1277 return VisitChildren(C); 1278} 1279 1280CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1281 AddStmtChoice asc) { 1282 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1283 appendStmt(ConfluenceBlock, C); 1284 if (badCFG) 1285 return 0; 1286 1287 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1288 Succ = ConfluenceBlock; 1289 Block = NULL; 1290 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1291 if (badCFG) 1292 return 0; 1293 1294 Succ = ConfluenceBlock; 1295 Block = NULL; 1296 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1297 if (badCFG) 1298 return 0; 1299 1300 Block = createBlock(false); 1301 // See if this is a known constant. 1302 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1303 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1304 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1305 Block->setTerminator(C); 1306 return addStmt(C->getCond()); 1307} 1308 1309 1310CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1311 addLocalScopeAndDtors(C); 1312 CFGBlock *LastBlock = Block; 1313 1314 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1315 I != E; ++I ) { 1316 // If we hit a segment of code just containing ';' (NullStmts), we can 1317 // get a null block back. In such cases, just use the LastBlock 1318 if (CFGBlock *newBlock = addStmt(*I)) 1319 LastBlock = newBlock; 1320 1321 if (badCFG) 1322 return NULL; 1323 } 1324 1325 return LastBlock; 1326} 1327 1328CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1329 AddStmtChoice asc) { 1330 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1331 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1332 1333 // Create the confluence block that will "merge" the results of the ternary 1334 // expression. 1335 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1336 appendStmt(ConfluenceBlock, C); 1337 if (badCFG) 1338 return 0; 1339 1340 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1341 1342 // Create a block for the LHS expression if there is an LHS expression. A 1343 // GCC extension allows LHS to be NULL, causing the condition to be the 1344 // value that is returned instead. 1345 // e.g: x ?: y is shorthand for: x ? x : y; 1346 Succ = ConfluenceBlock; 1347 Block = NULL; 1348 CFGBlock *LHSBlock = 0; 1349 const Expr *trueExpr = C->getTrueExpr(); 1350 if (trueExpr != opaqueValue) { 1351 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1352 if (badCFG) 1353 return 0; 1354 Block = NULL; 1355 } 1356 else 1357 LHSBlock = ConfluenceBlock; 1358 1359 // Create the block for the RHS expression. 1360 Succ = ConfluenceBlock; 1361 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1362 if (badCFG) 1363 return 0; 1364 1365 // Create the block that will contain the condition. 1366 Block = createBlock(false); 1367 1368 // See if this is a known constant. 1369 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1370 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1371 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1372 Block->setTerminator(C); 1373 Expr *condExpr = C->getCond(); 1374 1375 if (opaqueValue) { 1376 // Run the condition expression if it's not trivially expressed in 1377 // terms of the opaque value (or if there is no opaque value). 1378 if (condExpr != opaqueValue) 1379 addStmt(condExpr); 1380 1381 // Before that, run the common subexpression if there was one. 1382 // At least one of this or the above will be run. 1383 return addStmt(BCO->getCommon()); 1384 } 1385 1386 return addStmt(condExpr); 1387} 1388 1389CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1390 // Check if the Decl is for an __label__. If so, elide it from the 1391 // CFG entirely. 1392 if (isa<LabelDecl>(*DS->decl_begin())) 1393 return Block; 1394 1395 // This case also handles static_asserts. 1396 if (DS->isSingleDecl()) 1397 return VisitDeclSubExpr(DS); 1398 1399 CFGBlock *B = 0; 1400 1401 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1402 typedef SmallVector<Decl*,10> BufTy; 1403 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1404 1405 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1406 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1407 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1408 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1409 1410 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1411 // automatically freed with the CFG. 1412 DeclGroupRef DG(*I); 1413 Decl *D = *I; 1414 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1415 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1416 1417 // Append the fake DeclStmt to block. 1418 B = VisitDeclSubExpr(DSNew); 1419 } 1420 1421 return B; 1422} 1423 1424/// VisitDeclSubExpr - Utility method to add block-level expressions for 1425/// DeclStmts and initializers in them. 1426CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1427 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1428 Decl *D = DS->getSingleDecl(); 1429 1430 if (isa<StaticAssertDecl>(D)) { 1431 // static_asserts aren't added to the CFG because they do not impact 1432 // runtime semantics. 1433 return Block; 1434 } 1435 1436 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1437 1438 if (!VD) { 1439 autoCreateBlock(); 1440 appendStmt(Block, DS); 1441 return Block; 1442 } 1443 1444 bool IsReference = false; 1445 bool HasTemporaries = false; 1446 1447 // Destructors of temporaries in initialization expression should be called 1448 // after initialization finishes. 1449 Expr *Init = VD->getInit(); 1450 if (Init) { 1451 IsReference = VD->getType()->isReferenceType(); 1452 HasTemporaries = isa<ExprWithCleanups>(Init); 1453 1454 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1455 // Generate destructors for temporaries in initialization expression. 1456 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1457 IsReference); 1458 } 1459 } 1460 1461 autoCreateBlock(); 1462 appendStmt(Block, DS); 1463 1464 if (Init) { 1465 if (HasTemporaries) 1466 // For expression with temporaries go directly to subexpression to omit 1467 // generating destructors for the second time. 1468 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1469 else 1470 Visit(Init); 1471 } 1472 1473 // If the type of VD is a VLA, then we must process its size expressions. 1474 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1475 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1476 Block = addStmt(VA->getSizeExpr()); 1477 1478 // Remove variable from local scope. 1479 if (ScopePos && VD == *ScopePos) 1480 ++ScopePos; 1481 1482 return Block; 1483} 1484 1485CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1486 // We may see an if statement in the middle of a basic block, or it may be the 1487 // first statement we are processing. In either case, we create a new basic 1488 // block. First, we create the blocks for the then...else statements, and 1489 // then we create the block containing the if statement. If we were in the 1490 // middle of a block, we stop processing that block. That block is then the 1491 // implicit successor for the "then" and "else" clauses. 1492 1493 // Save local scope position because in case of condition variable ScopePos 1494 // won't be restored when traversing AST. 1495 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1496 1497 // Create local scope for possible condition variable. 1498 // Store scope position. Add implicit destructor. 1499 if (VarDecl *VD = I->getConditionVariable()) { 1500 LocalScope::const_iterator BeginScopePos = ScopePos; 1501 addLocalScopeForVarDecl(VD); 1502 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1503 } 1504 1505 // The block we were processing is now finished. Make it the successor 1506 // block. 1507 if (Block) { 1508 Succ = Block; 1509 if (badCFG) 1510 return 0; 1511 } 1512 1513 // Process the false branch. 1514 CFGBlock *ElseBlock = Succ; 1515 1516 if (Stmt *Else = I->getElse()) { 1517 SaveAndRestore<CFGBlock*> sv(Succ); 1518 1519 // NULL out Block so that the recursive call to Visit will 1520 // create a new basic block. 1521 Block = NULL; 1522 1523 // If branch is not a compound statement create implicit scope 1524 // and add destructors. 1525 if (!isa<CompoundStmt>(Else)) 1526 addLocalScopeAndDtors(Else); 1527 1528 ElseBlock = addStmt(Else); 1529 1530 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1531 ElseBlock = sv.get(); 1532 else if (Block) { 1533 if (badCFG) 1534 return 0; 1535 } 1536 } 1537 1538 // Process the true branch. 1539 CFGBlock *ThenBlock; 1540 { 1541 Stmt *Then = I->getThen(); 1542 assert(Then); 1543 SaveAndRestore<CFGBlock*> sv(Succ); 1544 Block = NULL; 1545 1546 // If branch is not a compound statement create implicit scope 1547 // and add destructors. 1548 if (!isa<CompoundStmt>(Then)) 1549 addLocalScopeAndDtors(Then); 1550 1551 ThenBlock = addStmt(Then); 1552 1553 if (!ThenBlock) { 1554 // We can reach here if the "then" body has all NullStmts. 1555 // Create an empty block so we can distinguish between true and false 1556 // branches in path-sensitive analyses. 1557 ThenBlock = createBlock(false); 1558 addSuccessor(ThenBlock, sv.get()); 1559 } else if (Block) { 1560 if (badCFG) 1561 return 0; 1562 } 1563 } 1564 1565 // Now create a new block containing the if statement. 1566 Block = createBlock(false); 1567 1568 // Set the terminator of the new block to the If statement. 1569 Block->setTerminator(I); 1570 1571 // See if this is a known constant. 1572 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1573 1574 // Now add the successors. 1575 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1576 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1577 1578 // Add the condition as the last statement in the new block. This may create 1579 // new blocks as the condition may contain control-flow. Any newly created 1580 // blocks will be pointed to be "Block". 1581 Block = addStmt(I->getCond()); 1582 1583 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1584 // and the condition variable initialization to the CFG. 1585 if (VarDecl *VD = I->getConditionVariable()) { 1586 if (Expr *Init = VD->getInit()) { 1587 autoCreateBlock(); 1588 appendStmt(Block, I->getConditionVariableDeclStmt()); 1589 addStmt(Init); 1590 } 1591 } 1592 1593 return Block; 1594} 1595 1596 1597CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1598 // If we were in the middle of a block we stop processing that block. 1599 // 1600 // NOTE: If a "return" appears in the middle of a block, this means that the 1601 // code afterwards is DEAD (unreachable). We still keep a basic block 1602 // for that code; a simple "mark-and-sweep" from the entry block will be 1603 // able to report such dead blocks. 1604 1605 // Create the new block. 1606 Block = createBlock(false); 1607 1608 // The Exit block is the only successor. 1609 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1610 addSuccessor(Block, &cfg->getExit()); 1611 1612 // Add the return statement to the block. This may create new blocks if R 1613 // contains control-flow (short-circuit operations). 1614 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1615} 1616 1617CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1618 // Get the block of the labeled statement. Add it to our map. 1619 addStmt(L->getSubStmt()); 1620 CFGBlock *LabelBlock = Block; 1621 1622 if (!LabelBlock) // This can happen when the body is empty, i.e. 1623 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1624 1625 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1626 "label already in map"); 1627 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1628 1629 // Labels partition blocks, so this is the end of the basic block we were 1630 // processing (L is the block's label). Because this is label (and we have 1631 // already processed the substatement) there is no extra control-flow to worry 1632 // about. 1633 LabelBlock->setLabel(L); 1634 if (badCFG) 1635 return 0; 1636 1637 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1638 Block = NULL; 1639 1640 // This block is now the implicit successor of other blocks. 1641 Succ = LabelBlock; 1642 1643 return LabelBlock; 1644} 1645 1646CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1647 // Goto is a control-flow statement. Thus we stop processing the current 1648 // block and create a new one. 1649 1650 Block = createBlock(false); 1651 Block->setTerminator(G); 1652 1653 // If we already know the mapping to the label block add the successor now. 1654 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1655 1656 if (I == LabelMap.end()) 1657 // We will need to backpatch this block later. 1658 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1659 else { 1660 JumpTarget JT = I->second; 1661 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1662 addSuccessor(Block, JT.block); 1663 } 1664 1665 return Block; 1666} 1667 1668CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1669 CFGBlock *LoopSuccessor = NULL; 1670 1671 // Save local scope position because in case of condition variable ScopePos 1672 // won't be restored when traversing AST. 1673 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1674 1675 // Create local scope for init statement and possible condition variable. 1676 // Add destructor for init statement and condition variable. 1677 // Store scope position for continue statement. 1678 if (Stmt *Init = F->getInit()) 1679 addLocalScopeForStmt(Init); 1680 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1681 1682 if (VarDecl *VD = F->getConditionVariable()) 1683 addLocalScopeForVarDecl(VD); 1684 LocalScope::const_iterator ContinueScopePos = ScopePos; 1685 1686 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1687 1688 // "for" is a control-flow statement. Thus we stop processing the current 1689 // block. 1690 if (Block) { 1691 if (badCFG) 1692 return 0; 1693 LoopSuccessor = Block; 1694 } else 1695 LoopSuccessor = Succ; 1696 1697 // Save the current value for the break targets. 1698 // All breaks should go to the code following the loop. 1699 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1700 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1701 1702 // Because of short-circuit evaluation, the condition of the loop can span 1703 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1704 // evaluate the condition. 1705 CFGBlock *ExitConditionBlock = createBlock(false); 1706 CFGBlock *EntryConditionBlock = ExitConditionBlock; 1707 1708 // Set the terminator for the "exit" condition block. 1709 ExitConditionBlock->setTerminator(F); 1710 1711 // Now add the actual condition to the condition block. Because the condition 1712 // itself may contain control-flow, new blocks may be created. 1713 if (Stmt *C = F->getCond()) { 1714 Block = ExitConditionBlock; 1715 EntryConditionBlock = addStmt(C); 1716 if (badCFG) 1717 return 0; 1718 assert(Block == EntryConditionBlock || 1719 (Block == 0 && EntryConditionBlock == Succ)); 1720 1721 // If this block contains a condition variable, add both the condition 1722 // variable and initializer to the CFG. 1723 if (VarDecl *VD = F->getConditionVariable()) { 1724 if (Expr *Init = VD->getInit()) { 1725 autoCreateBlock(); 1726 appendStmt(Block, F->getConditionVariableDeclStmt()); 1727 EntryConditionBlock = addStmt(Init); 1728 assert(Block == EntryConditionBlock); 1729 } 1730 } 1731 1732 if (Block) { 1733 if (badCFG) 1734 return 0; 1735 } 1736 } 1737 1738 // The condition block is the implicit successor for the loop body as well as 1739 // any code above the loop. 1740 Succ = EntryConditionBlock; 1741 1742 // See if this is a known constant. 1743 TryResult KnownVal(true); 1744 1745 if (F->getCond()) 1746 KnownVal = tryEvaluateBool(F->getCond()); 1747 1748 // Now create the loop body. 1749 { 1750 assert(F->getBody()); 1751 1752 // Save the current values for Block, Succ, and continue targets. 1753 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1754 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1755 1756 // Create a new block to contain the (bottom) of the loop body. 1757 Block = NULL; 1758 1759 // Loop body should end with destructor of Condition variable (if any). 1760 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1761 1762 if (Stmt *I = F->getInc()) { 1763 // Generate increment code in its own basic block. This is the target of 1764 // continue statements. 1765 Succ = addStmt(I); 1766 } else { 1767 // No increment code. Create a special, empty, block that is used as the 1768 // target block for "looping back" to the start of the loop. 1769 assert(Succ == EntryConditionBlock); 1770 Succ = Block ? Block : createBlock(); 1771 } 1772 1773 // Finish up the increment (or empty) block if it hasn't been already. 1774 if (Block) { 1775 assert(Block == Succ); 1776 if (badCFG) 1777 return 0; 1778 Block = 0; 1779 } 1780 1781 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1782 1783 // The starting block for the loop increment is the block that should 1784 // represent the 'loop target' for looping back to the start of the loop. 1785 ContinueJumpTarget.block->setLoopTarget(F); 1786 1787 // If body is not a compound statement create implicit scope 1788 // and add destructors. 1789 if (!isa<CompoundStmt>(F->getBody())) 1790 addLocalScopeAndDtors(F->getBody()); 1791 1792 // Now populate the body block, and in the process create new blocks as we 1793 // walk the body of the loop. 1794 CFGBlock *BodyBlock = addStmt(F->getBody()); 1795 1796 if (!BodyBlock) 1797 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1798 else if (badCFG) 1799 return 0; 1800 1801 // This new body block is a successor to our "exit" condition block. 1802 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1803 } 1804 1805 // Link up the condition block with the code that follows the loop. (the 1806 // false branch). 1807 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1808 1809 // If the loop contains initialization, create a new block for those 1810 // statements. This block can also contain statements that precede the loop. 1811 if (Stmt *I = F->getInit()) { 1812 Block = createBlock(); 1813 return addStmt(I); 1814 } 1815 1816 // There is no loop initialization. We are thus basically a while loop. 1817 // NULL out Block to force lazy block construction. 1818 Block = NULL; 1819 Succ = EntryConditionBlock; 1820 return EntryConditionBlock; 1821} 1822 1823CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1824 if (asc.alwaysAdd(*this, M)) { 1825 autoCreateBlock(); 1826 appendStmt(Block, M); 1827 } 1828 return Visit(M->getBase()); 1829} 1830 1831CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 1832 // Objective-C fast enumeration 'for' statements: 1833 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1834 // 1835 // for ( Type newVariable in collection_expression ) { statements } 1836 // 1837 // becomes: 1838 // 1839 // prologue: 1840 // 1. collection_expression 1841 // T. jump to loop_entry 1842 // loop_entry: 1843 // 1. side-effects of element expression 1844 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1845 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1846 // TB: 1847 // statements 1848 // T. jump to loop_entry 1849 // FB: 1850 // what comes after 1851 // 1852 // and 1853 // 1854 // Type existingItem; 1855 // for ( existingItem in expression ) { statements } 1856 // 1857 // becomes: 1858 // 1859 // the same with newVariable replaced with existingItem; the binding works 1860 // the same except that for one ObjCForCollectionStmt::getElement() returns 1861 // a DeclStmt and the other returns a DeclRefExpr. 1862 // 1863 1864 CFGBlock *LoopSuccessor = 0; 1865 1866 if (Block) { 1867 if (badCFG) 1868 return 0; 1869 LoopSuccessor = Block; 1870 Block = 0; 1871 } else 1872 LoopSuccessor = Succ; 1873 1874 // Build the condition blocks. 1875 CFGBlock *ExitConditionBlock = createBlock(false); 1876 1877 // Set the terminator for the "exit" condition block. 1878 ExitConditionBlock->setTerminator(S); 1879 1880 // The last statement in the block should be the ObjCForCollectionStmt, which 1881 // performs the actual binding to 'element' and determines if there are any 1882 // more items in the collection. 1883 appendStmt(ExitConditionBlock, S); 1884 Block = ExitConditionBlock; 1885 1886 // Walk the 'element' expression to see if there are any side-effects. We 1887 // generate new blocks as necessary. We DON'T add the statement by default to 1888 // the CFG unless it contains control-flow. 1889 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 1890 AddStmtChoice::NotAlwaysAdd); 1891 if (Block) { 1892 if (badCFG) 1893 return 0; 1894 Block = 0; 1895 } 1896 1897 // The condition block is the implicit successor for the loop body as well as 1898 // any code above the loop. 1899 Succ = EntryConditionBlock; 1900 1901 // Now create the true branch. 1902 { 1903 // Save the current values for Succ, continue and break targets. 1904 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1905 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1906 save_break(BreakJumpTarget); 1907 1908 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1909 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1910 1911 CFGBlock *BodyBlock = addStmt(S->getBody()); 1912 1913 if (!BodyBlock) 1914 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1915 else if (Block) { 1916 if (badCFG) 1917 return 0; 1918 } 1919 1920 // This new body block is a successor to our "exit" condition block. 1921 addSuccessor(ExitConditionBlock, BodyBlock); 1922 } 1923 1924 // Link up the condition block with the code that follows the loop. 1925 // (the false branch). 1926 addSuccessor(ExitConditionBlock, LoopSuccessor); 1927 1928 // Now create a prologue block to contain the collection expression. 1929 Block = createBlock(); 1930 return addStmt(S->getCollection()); 1931} 1932 1933CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 1934 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1935 1936 // Inline the body. 1937 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1938 1939 // The sync body starts its own basic block. This makes it a little easier 1940 // for diagnostic clients. 1941 if (SyncBlock) { 1942 if (badCFG) 1943 return 0; 1944 1945 Block = 0; 1946 Succ = SyncBlock; 1947 } 1948 1949 // Add the @synchronized to the CFG. 1950 autoCreateBlock(); 1951 appendStmt(Block, S); 1952 1953 // Inline the sync expression. 1954 return addStmt(S->getSynchExpr()); 1955} 1956 1957CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 1958 // FIXME 1959 return NYS(); 1960} 1961 1962CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) { 1963 autoCreateBlock(); 1964 1965 // Add the PseudoObject as the last thing. 1966 appendStmt(Block, E); 1967 1968 CFGBlock *lastBlock = Block; 1969 1970 // Before that, evaluate all of the semantics in order. In 1971 // CFG-land, that means appending them in reverse order. 1972 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) { 1973 Expr *Semantic = E->getSemanticExpr(--i); 1974 1975 // If the semantic is an opaque value, we're being asked to bind 1976 // it to its source expression. 1977 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic)) 1978 Semantic = OVE->getSourceExpr(); 1979 1980 if (CFGBlock *B = Visit(Semantic)) 1981 lastBlock = B; 1982 } 1983 1984 return lastBlock; 1985} 1986 1987CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 1988 CFGBlock *LoopSuccessor = NULL; 1989 1990 // Save local scope position because in case of condition variable ScopePos 1991 // won't be restored when traversing AST. 1992 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1993 1994 // Create local scope for possible condition variable. 1995 // Store scope position for continue statement. 1996 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1997 if (VarDecl *VD = W->getConditionVariable()) { 1998 addLocalScopeForVarDecl(VD); 1999 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2000 } 2001 2002 // "while" is a control-flow statement. Thus we stop processing the current 2003 // block. 2004 if (Block) { 2005 if (badCFG) 2006 return 0; 2007 LoopSuccessor = Block; 2008 Block = 0; 2009 } else 2010 LoopSuccessor = Succ; 2011 2012 // Because of short-circuit evaluation, the condition of the loop can span 2013 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2014 // evaluate the condition. 2015 CFGBlock *ExitConditionBlock = createBlock(false); 2016 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2017 2018 // Set the terminator for the "exit" condition block. 2019 ExitConditionBlock->setTerminator(W); 2020 2021 // Now add the actual condition to the condition block. Because the condition 2022 // itself may contain control-flow, new blocks may be created. Thus we update 2023 // "Succ" after adding the condition. 2024 if (Stmt *C = W->getCond()) { 2025 Block = ExitConditionBlock; 2026 EntryConditionBlock = addStmt(C); 2027 // The condition might finish the current 'Block'. 2028 Block = EntryConditionBlock; 2029 2030 // If this block contains a condition variable, add both the condition 2031 // variable and initializer to the CFG. 2032 if (VarDecl *VD = W->getConditionVariable()) { 2033 if (Expr *Init = VD->getInit()) { 2034 autoCreateBlock(); 2035 appendStmt(Block, W->getConditionVariableDeclStmt()); 2036 EntryConditionBlock = addStmt(Init); 2037 assert(Block == EntryConditionBlock); 2038 } 2039 } 2040 2041 if (Block) { 2042 if (badCFG) 2043 return 0; 2044 } 2045 } 2046 2047 // The condition block is the implicit successor for the loop body as well as 2048 // any code above the loop. 2049 Succ = EntryConditionBlock; 2050 2051 // See if this is a known constant. 2052 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 2053 2054 // Process the loop body. 2055 { 2056 assert(W->getBody()); 2057 2058 // Save the current values for Block, Succ, and continue and break targets 2059 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2060 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2061 save_break(BreakJumpTarget); 2062 2063 // Create an empty block to represent the transition block for looping back 2064 // to the head of the loop. 2065 Block = 0; 2066 assert(Succ == EntryConditionBlock); 2067 Succ = createBlock(); 2068 Succ->setLoopTarget(W); 2069 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 2070 2071 // All breaks should go to the code following the loop. 2072 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2073 2074 // NULL out Block to force lazy instantiation of blocks for the body. 2075 Block = NULL; 2076 2077 // Loop body should end with destructor of Condition variable (if any). 2078 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2079 2080 // If body is not a compound statement create implicit scope 2081 // and add destructors. 2082 if (!isa<CompoundStmt>(W->getBody())) 2083 addLocalScopeAndDtors(W->getBody()); 2084 2085 // Create the body. The returned block is the entry to the loop body. 2086 CFGBlock *BodyBlock = addStmt(W->getBody()); 2087 2088 if (!BodyBlock) 2089 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2090 else if (Block) { 2091 if (badCFG) 2092 return 0; 2093 } 2094 2095 // Add the loop body entry as a successor to the condition. 2096 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2097 } 2098 2099 // Link up the condition block with the code that follows the loop. (the 2100 // false branch). 2101 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2102 2103 // There can be no more statements in the condition block since we loop back 2104 // to this block. NULL out Block to force lazy creation of another block. 2105 Block = NULL; 2106 2107 // Return the condition block, which is the dominating block for the loop. 2108 Succ = EntryConditionBlock; 2109 return EntryConditionBlock; 2110} 2111 2112 2113CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2114 // FIXME: For now we pretend that @catch and the code it contains does not 2115 // exit. 2116 return Block; 2117} 2118 2119CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2120 // FIXME: This isn't complete. We basically treat @throw like a return 2121 // statement. 2122 2123 // If we were in the middle of a block we stop processing that block. 2124 if (badCFG) 2125 return 0; 2126 2127 // Create the new block. 2128 Block = createBlock(false); 2129 2130 // The Exit block is the only successor. 2131 addSuccessor(Block, &cfg->getExit()); 2132 2133 // Add the statement to the block. This may create new blocks if S contains 2134 // control-flow (short-circuit operations). 2135 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2136} 2137 2138CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2139 // If we were in the middle of a block we stop processing that block. 2140 if (badCFG) 2141 return 0; 2142 2143 // Create the new block. 2144 Block = createBlock(false); 2145 2146 if (TryTerminatedBlock) 2147 // The current try statement is the only successor. 2148 addSuccessor(Block, TryTerminatedBlock); 2149 else 2150 // otherwise the Exit block is the only successor. 2151 addSuccessor(Block, &cfg->getExit()); 2152 2153 // Add the statement to the block. This may create new blocks if S contains 2154 // control-flow (short-circuit operations). 2155 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2156} 2157 2158CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2159 CFGBlock *LoopSuccessor = NULL; 2160 2161 // "do...while" is a control-flow statement. Thus we stop processing the 2162 // current block. 2163 if (Block) { 2164 if (badCFG) 2165 return 0; 2166 LoopSuccessor = Block; 2167 } else 2168 LoopSuccessor = Succ; 2169 2170 // Because of short-circuit evaluation, the condition of the loop can span 2171 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2172 // evaluate the condition. 2173 CFGBlock *ExitConditionBlock = createBlock(false); 2174 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2175 2176 // Set the terminator for the "exit" condition block. 2177 ExitConditionBlock->setTerminator(D); 2178 2179 // Now add the actual condition to the condition block. Because the condition 2180 // itself may contain control-flow, new blocks may be created. 2181 if (Stmt *C = D->getCond()) { 2182 Block = ExitConditionBlock; 2183 EntryConditionBlock = addStmt(C); 2184 if (Block) { 2185 if (badCFG) 2186 return 0; 2187 } 2188 } 2189 2190 // The condition block is the implicit successor for the loop body. 2191 Succ = EntryConditionBlock; 2192 2193 // See if this is a known constant. 2194 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2195 2196 // Process the loop body. 2197 CFGBlock *BodyBlock = NULL; 2198 { 2199 assert(D->getBody()); 2200 2201 // Save the current values for Block, Succ, and continue and break targets 2202 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2203 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2204 save_break(BreakJumpTarget); 2205 2206 // All continues within this loop should go to the condition block 2207 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2208 2209 // All breaks should go to the code following the loop. 2210 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2211 2212 // NULL out Block to force lazy instantiation of blocks for the body. 2213 Block = NULL; 2214 2215 // If body is not a compound statement create implicit scope 2216 // and add destructors. 2217 if (!isa<CompoundStmt>(D->getBody())) 2218 addLocalScopeAndDtors(D->getBody()); 2219 2220 // Create the body. The returned block is the entry to the loop body. 2221 BodyBlock = addStmt(D->getBody()); 2222 2223 if (!BodyBlock) 2224 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2225 else if (Block) { 2226 if (badCFG) 2227 return 0; 2228 } 2229 2230 if (!KnownVal.isFalse()) { 2231 // Add an intermediate block between the BodyBlock and the 2232 // ExitConditionBlock to represent the "loop back" transition. Create an 2233 // empty block to represent the transition block for looping back to the 2234 // head of the loop. 2235 // FIXME: Can we do this more efficiently without adding another block? 2236 Block = NULL; 2237 Succ = BodyBlock; 2238 CFGBlock *LoopBackBlock = createBlock(); 2239 LoopBackBlock->setLoopTarget(D); 2240 2241 // Add the loop body entry as a successor to the condition. 2242 addSuccessor(ExitConditionBlock, LoopBackBlock); 2243 } 2244 else 2245 addSuccessor(ExitConditionBlock, NULL); 2246 } 2247 2248 // Link up the condition block with the code that follows the loop. 2249 // (the false branch). 2250 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2251 2252 // There can be no more statements in the body block(s) since we loop back to 2253 // the body. NULL out Block to force lazy creation of another block. 2254 Block = NULL; 2255 2256 // Return the loop body, which is the dominating block for the loop. 2257 Succ = BodyBlock; 2258 return BodyBlock; 2259} 2260 2261CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2262 // "continue" is a control-flow statement. Thus we stop processing the 2263 // current block. 2264 if (badCFG) 2265 return 0; 2266 2267 // Now create a new block that ends with the continue statement. 2268 Block = createBlock(false); 2269 Block->setTerminator(C); 2270 2271 // If there is no target for the continue, then we are looking at an 2272 // incomplete AST. This means the CFG cannot be constructed. 2273 if (ContinueJumpTarget.block) { 2274 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2275 addSuccessor(Block, ContinueJumpTarget.block); 2276 } else 2277 badCFG = true; 2278 2279 return Block; 2280} 2281 2282CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2283 AddStmtChoice asc) { 2284 2285 if (asc.alwaysAdd(*this, E)) { 2286 autoCreateBlock(); 2287 appendStmt(Block, E); 2288 } 2289 2290 // VLA types have expressions that must be evaluated. 2291 CFGBlock *lastBlock = Block; 2292 2293 if (E->isArgumentType()) { 2294 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2295 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2296 lastBlock = addStmt(VA->getSizeExpr()); 2297 } 2298 return lastBlock; 2299} 2300 2301/// VisitStmtExpr - Utility method to handle (nested) statement 2302/// expressions (a GCC extension). 2303CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2304 if (asc.alwaysAdd(*this, SE)) { 2305 autoCreateBlock(); 2306 appendStmt(Block, SE); 2307 } 2308 return VisitCompoundStmt(SE->getSubStmt()); 2309} 2310 2311CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2312 // "switch" is a control-flow statement. Thus we stop processing the current 2313 // block. 2314 CFGBlock *SwitchSuccessor = NULL; 2315 2316 // Save local scope position because in case of condition variable ScopePos 2317 // won't be restored when traversing AST. 2318 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2319 2320 // Create local scope for possible condition variable. 2321 // Store scope position. Add implicit destructor. 2322 if (VarDecl *VD = Terminator->getConditionVariable()) { 2323 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2324 addLocalScopeForVarDecl(VD); 2325 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2326 } 2327 2328 if (Block) { 2329 if (badCFG) 2330 return 0; 2331 SwitchSuccessor = Block; 2332 } else SwitchSuccessor = Succ; 2333 2334 // Save the current "switch" context. 2335 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2336 save_default(DefaultCaseBlock); 2337 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2338 2339 // Set the "default" case to be the block after the switch statement. If the 2340 // switch statement contains a "default:", this value will be overwritten with 2341 // the block for that code. 2342 DefaultCaseBlock = SwitchSuccessor; 2343 2344 // Create a new block that will contain the switch statement. 2345 SwitchTerminatedBlock = createBlock(false); 2346 2347 // Now process the switch body. The code after the switch is the implicit 2348 // successor. 2349 Succ = SwitchSuccessor; 2350 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2351 2352 // When visiting the body, the case statements should automatically get linked 2353 // up to the switch. We also don't keep a pointer to the body, since all 2354 // control-flow from the switch goes to case/default statements. 2355 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2356 Block = NULL; 2357 2358 // For pruning unreachable case statements, save the current state 2359 // for tracking the condition value. 2360 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2361 false); 2362 2363 // Determine if the switch condition can be explicitly evaluated. 2364 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2365 Expr::EvalResult result; 2366 bool b = tryEvaluate(Terminator->getCond(), result); 2367 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2368 b ? &result : 0); 2369 2370 // If body is not a compound statement create implicit scope 2371 // and add destructors. 2372 if (!isa<CompoundStmt>(Terminator->getBody())) 2373 addLocalScopeAndDtors(Terminator->getBody()); 2374 2375 addStmt(Terminator->getBody()); 2376 if (Block) { 2377 if (badCFG) 2378 return 0; 2379 } 2380 2381 // If we have no "default:" case, the default transition is to the code 2382 // following the switch body. Moreover, take into account if all the 2383 // cases of a switch are covered (e.g., switching on an enum value). 2384 addSuccessor(SwitchTerminatedBlock, 2385 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2386 ? 0 : DefaultCaseBlock); 2387 2388 // Add the terminator and condition in the switch block. 2389 SwitchTerminatedBlock->setTerminator(Terminator); 2390 Block = SwitchTerminatedBlock; 2391 Block = addStmt(Terminator->getCond()); 2392 2393 // Finally, if the SwitchStmt contains a condition variable, add both the 2394 // SwitchStmt and the condition variable initialization to the CFG. 2395 if (VarDecl *VD = Terminator->getConditionVariable()) { 2396 if (Expr *Init = VD->getInit()) { 2397 autoCreateBlock(); 2398 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2399 addStmt(Init); 2400 } 2401 } 2402 2403 return Block; 2404} 2405 2406static bool shouldAddCase(bool &switchExclusivelyCovered, 2407 const Expr::EvalResult *switchCond, 2408 const CaseStmt *CS, 2409 ASTContext &Ctx) { 2410 if (!switchCond) 2411 return true; 2412 2413 bool addCase = false; 2414 2415 if (!switchExclusivelyCovered) { 2416 if (switchCond->Val.isInt()) { 2417 // Evaluate the LHS of the case value. 2418 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2419 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2420 2421 if (condInt == lhsInt) { 2422 addCase = true; 2423 switchExclusivelyCovered = true; 2424 } 2425 else if (condInt < lhsInt) { 2426 if (const Expr *RHS = CS->getRHS()) { 2427 // Evaluate the RHS of the case value. 2428 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2429 if (V2 <= condInt) { 2430 addCase = true; 2431 switchExclusivelyCovered = true; 2432 } 2433 } 2434 } 2435 } 2436 else 2437 addCase = true; 2438 } 2439 return addCase; 2440} 2441 2442CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2443 // CaseStmts are essentially labels, so they are the first statement in a 2444 // block. 2445 CFGBlock *TopBlock = 0, *LastBlock = 0; 2446 2447 if (Stmt *Sub = CS->getSubStmt()) { 2448 // For deeply nested chains of CaseStmts, instead of doing a recursion 2449 // (which can blow out the stack), manually unroll and create blocks 2450 // along the way. 2451 while (isa<CaseStmt>(Sub)) { 2452 CFGBlock *currentBlock = createBlock(false); 2453 currentBlock->setLabel(CS); 2454 2455 if (TopBlock) 2456 addSuccessor(LastBlock, currentBlock); 2457 else 2458 TopBlock = currentBlock; 2459 2460 addSuccessor(SwitchTerminatedBlock, 2461 shouldAddCase(switchExclusivelyCovered, switchCond, 2462 CS, *Context) 2463 ? currentBlock : 0); 2464 2465 LastBlock = currentBlock; 2466 CS = cast<CaseStmt>(Sub); 2467 Sub = CS->getSubStmt(); 2468 } 2469 2470 addStmt(Sub); 2471 } 2472 2473 CFGBlock *CaseBlock = Block; 2474 if (!CaseBlock) 2475 CaseBlock = createBlock(); 2476 2477 // Cases statements partition blocks, so this is the top of the basic block we 2478 // were processing (the "case XXX:" is the label). 2479 CaseBlock->setLabel(CS); 2480 2481 if (badCFG) 2482 return 0; 2483 2484 // Add this block to the list of successors for the block with the switch 2485 // statement. 2486 assert(SwitchTerminatedBlock); 2487 addSuccessor(SwitchTerminatedBlock, 2488 shouldAddCase(switchExclusivelyCovered, switchCond, 2489 CS, *Context) 2490 ? CaseBlock : 0); 2491 2492 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2493 Block = NULL; 2494 2495 if (TopBlock) { 2496 addSuccessor(LastBlock, CaseBlock); 2497 Succ = TopBlock; 2498 } else { 2499 // This block is now the implicit successor of other blocks. 2500 Succ = CaseBlock; 2501 } 2502 2503 return Succ; 2504} 2505 2506CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2507 if (Terminator->getSubStmt()) 2508 addStmt(Terminator->getSubStmt()); 2509 2510 DefaultCaseBlock = Block; 2511 2512 if (!DefaultCaseBlock) 2513 DefaultCaseBlock = createBlock(); 2514 2515 // Default statements partition blocks, so this is the top of the basic block 2516 // we were processing (the "default:" is the label). 2517 DefaultCaseBlock->setLabel(Terminator); 2518 2519 if (badCFG) 2520 return 0; 2521 2522 // Unlike case statements, we don't add the default block to the successors 2523 // for the switch statement immediately. This is done when we finish 2524 // processing the switch statement. This allows for the default case 2525 // (including a fall-through to the code after the switch statement) to always 2526 // be the last successor of a switch-terminated block. 2527 2528 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2529 Block = NULL; 2530 2531 // This block is now the implicit successor of other blocks. 2532 Succ = DefaultCaseBlock; 2533 2534 return DefaultCaseBlock; 2535} 2536 2537CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2538 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2539 // current block. 2540 CFGBlock *TrySuccessor = NULL; 2541 2542 if (Block) { 2543 if (badCFG) 2544 return 0; 2545 TrySuccessor = Block; 2546 } else TrySuccessor = Succ; 2547 2548 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2549 2550 // Create a new block that will contain the try statement. 2551 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2552 // Add the terminator in the try block. 2553 NewTryTerminatedBlock->setTerminator(Terminator); 2554 2555 bool HasCatchAll = false; 2556 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2557 // The code after the try is the implicit successor. 2558 Succ = TrySuccessor; 2559 CXXCatchStmt *CS = Terminator->getHandler(h); 2560 if (CS->getExceptionDecl() == 0) { 2561 HasCatchAll = true; 2562 } 2563 Block = NULL; 2564 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2565 if (CatchBlock == 0) 2566 return 0; 2567 // Add this block to the list of successors for the block with the try 2568 // statement. 2569 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2570 } 2571 if (!HasCatchAll) { 2572 if (PrevTryTerminatedBlock) 2573 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2574 else 2575 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2576 } 2577 2578 // The code after the try is the implicit successor. 2579 Succ = TrySuccessor; 2580 2581 // Save the current "try" context. 2582 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2583 cfg->addTryDispatchBlock(TryTerminatedBlock); 2584 2585 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2586 Block = NULL; 2587 Block = addStmt(Terminator->getTryBlock()); 2588 return Block; 2589} 2590 2591CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2592 // CXXCatchStmt are treated like labels, so they are the first statement in a 2593 // block. 2594 2595 // Save local scope position because in case of exception variable ScopePos 2596 // won't be restored when traversing AST. 2597 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2598 2599 // Create local scope for possible exception variable. 2600 // Store scope position. Add implicit destructor. 2601 if (VarDecl *VD = CS->getExceptionDecl()) { 2602 LocalScope::const_iterator BeginScopePos = ScopePos; 2603 addLocalScopeForVarDecl(VD); 2604 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2605 } 2606 2607 if (CS->getHandlerBlock()) 2608 addStmt(CS->getHandlerBlock()); 2609 2610 CFGBlock *CatchBlock = Block; 2611 if (!CatchBlock) 2612 CatchBlock = createBlock(); 2613 2614 CatchBlock->setLabel(CS); 2615 2616 if (badCFG) 2617 return 0; 2618 2619 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2620 Block = NULL; 2621 2622 return CatchBlock; 2623} 2624 2625CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2626 // C++0x for-range statements are specified as [stmt.ranged]: 2627 // 2628 // { 2629 // auto && __range = range-init; 2630 // for ( auto __begin = begin-expr, 2631 // __end = end-expr; 2632 // __begin != __end; 2633 // ++__begin ) { 2634 // for-range-declaration = *__begin; 2635 // statement 2636 // } 2637 // } 2638 2639 // Save local scope position before the addition of the implicit variables. 2640 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2641 2642 // Create local scopes and destructors for range, begin and end variables. 2643 if (Stmt *Range = S->getRangeStmt()) 2644 addLocalScopeForStmt(Range); 2645 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2646 addLocalScopeForStmt(BeginEnd); 2647 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2648 2649 LocalScope::const_iterator ContinueScopePos = ScopePos; 2650 2651 // "for" is a control-flow statement. Thus we stop processing the current 2652 // block. 2653 CFGBlock *LoopSuccessor = NULL; 2654 if (Block) { 2655 if (badCFG) 2656 return 0; 2657 LoopSuccessor = Block; 2658 } else 2659 LoopSuccessor = Succ; 2660 2661 // Save the current value for the break targets. 2662 // All breaks should go to the code following the loop. 2663 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2664 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2665 2666 // The block for the __begin != __end expression. 2667 CFGBlock *ConditionBlock = createBlock(false); 2668 ConditionBlock->setTerminator(S); 2669 2670 // Now add the actual condition to the condition block. 2671 if (Expr *C = S->getCond()) { 2672 Block = ConditionBlock; 2673 CFGBlock *BeginConditionBlock = addStmt(C); 2674 if (badCFG) 2675 return 0; 2676 assert(BeginConditionBlock == ConditionBlock && 2677 "condition block in for-range was unexpectedly complex"); 2678 (void)BeginConditionBlock; 2679 } 2680 2681 // The condition block is the implicit successor for the loop body as well as 2682 // any code above the loop. 2683 Succ = ConditionBlock; 2684 2685 // See if this is a known constant. 2686 TryResult KnownVal(true); 2687 2688 if (S->getCond()) 2689 KnownVal = tryEvaluateBool(S->getCond()); 2690 2691 // Now create the loop body. 2692 { 2693 assert(S->getBody()); 2694 2695 // Save the current values for Block, Succ, and continue targets. 2696 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2697 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2698 2699 // Generate increment code in its own basic block. This is the target of 2700 // continue statements. 2701 Block = 0; 2702 Succ = addStmt(S->getInc()); 2703 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2704 2705 // The starting block for the loop increment is the block that should 2706 // represent the 'loop target' for looping back to the start of the loop. 2707 ContinueJumpTarget.block->setLoopTarget(S); 2708 2709 // Finish up the increment block and prepare to start the loop body. 2710 assert(Block); 2711 if (badCFG) 2712 return 0; 2713 Block = 0; 2714 2715 2716 // Add implicit scope and dtors for loop variable. 2717 addLocalScopeAndDtors(S->getLoopVarStmt()); 2718 2719 // Populate a new block to contain the loop body and loop variable. 2720 Block = addStmt(S->getBody()); 2721 if (badCFG) 2722 return 0; 2723 Block = addStmt(S->getLoopVarStmt()); 2724 if (badCFG) 2725 return 0; 2726 2727 // This new body block is a successor to our condition block. 2728 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2729 } 2730 2731 // Link up the condition block with the code that follows the loop (the 2732 // false branch). 2733 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2734 2735 // Add the initialization statements. 2736 Block = createBlock(); 2737 addStmt(S->getBeginEndStmt()); 2738 return addStmt(S->getRangeStmt()); 2739} 2740 2741CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2742 AddStmtChoice asc) { 2743 if (BuildOpts.AddImplicitDtors) { 2744 // If adding implicit destructors visit the full expression for adding 2745 // destructors of temporaries. 2746 VisitForTemporaryDtors(E->getSubExpr()); 2747 2748 // Full expression has to be added as CFGStmt so it will be sequenced 2749 // before destructors of it's temporaries. 2750 asc = asc.withAlwaysAdd(true); 2751 } 2752 return Visit(E->getSubExpr(), asc); 2753} 2754 2755CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2756 AddStmtChoice asc) { 2757 if (asc.alwaysAdd(*this, E)) { 2758 autoCreateBlock(); 2759 appendStmt(Block, E); 2760 2761 // We do not want to propagate the AlwaysAdd property. 2762 asc = asc.withAlwaysAdd(false); 2763 } 2764 return Visit(E->getSubExpr(), asc); 2765} 2766 2767CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2768 AddStmtChoice asc) { 2769 autoCreateBlock(); 2770 appendStmt(Block, C); 2771 2772 return VisitChildren(C); 2773} 2774 2775CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2776 AddStmtChoice asc) { 2777 if (asc.alwaysAdd(*this, E)) { 2778 autoCreateBlock(); 2779 appendStmt(Block, E); 2780 // We do not want to propagate the AlwaysAdd property. 2781 asc = asc.withAlwaysAdd(false); 2782 } 2783 return Visit(E->getSubExpr(), asc); 2784} 2785 2786CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2787 AddStmtChoice asc) { 2788 autoCreateBlock(); 2789 appendStmt(Block, C); 2790 return VisitChildren(C); 2791} 2792 2793CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2794 AddStmtChoice asc) { 2795 if (asc.alwaysAdd(*this, E)) { 2796 autoCreateBlock(); 2797 appendStmt(Block, E); 2798 } 2799 return Visit(E->getSubExpr(), AddStmtChoice()); 2800} 2801 2802CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 2803 // Lazily create the indirect-goto dispatch block if there isn't one already. 2804 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 2805 2806 if (!IBlock) { 2807 IBlock = createBlock(false); 2808 cfg->setIndirectGotoBlock(IBlock); 2809 } 2810 2811 // IndirectGoto is a control-flow statement. Thus we stop processing the 2812 // current block and create a new one. 2813 if (badCFG) 2814 return 0; 2815 2816 Block = createBlock(false); 2817 Block->setTerminator(I); 2818 addSuccessor(Block, IBlock); 2819 return addStmt(I->getTarget()); 2820} 2821 2822CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2823tryAgain: 2824 if (!E) { 2825 badCFG = true; 2826 return NULL; 2827 } 2828 switch (E->getStmtClass()) { 2829 default: 2830 return VisitChildrenForTemporaryDtors(E); 2831 2832 case Stmt::BinaryOperatorClass: 2833 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2834 2835 case Stmt::CXXBindTemporaryExprClass: 2836 return VisitCXXBindTemporaryExprForTemporaryDtors( 2837 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2838 2839 case Stmt::BinaryConditionalOperatorClass: 2840 case Stmt::ConditionalOperatorClass: 2841 return VisitConditionalOperatorForTemporaryDtors( 2842 cast<AbstractConditionalOperator>(E), BindToTemporary); 2843 2844 case Stmt::ImplicitCastExprClass: 2845 // For implicit cast we want BindToTemporary to be passed further. 2846 E = cast<CastExpr>(E)->getSubExpr(); 2847 goto tryAgain; 2848 2849 case Stmt::ParenExprClass: 2850 E = cast<ParenExpr>(E)->getSubExpr(); 2851 goto tryAgain; 2852 2853 case Stmt::MaterializeTemporaryExprClass: 2854 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 2855 goto tryAgain; 2856 } 2857} 2858 2859CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2860 // When visiting children for destructors we want to visit them in reverse 2861 // order. Because there's no reverse iterator for children must to reverse 2862 // them in helper vector. 2863 typedef SmallVector<Stmt *, 4> ChildrenVect; 2864 ChildrenVect ChildrenRev; 2865 for (Stmt::child_range I = E->children(); I; ++I) { 2866 if (*I) ChildrenRev.push_back(*I); 2867 } 2868 2869 CFGBlock *B = Block; 2870 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2871 L = ChildrenRev.rend(); I != L; ++I) { 2872 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2873 B = R; 2874 } 2875 return B; 2876} 2877 2878CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2879 if (E->isLogicalOp()) { 2880 // Destructors for temporaries in LHS expression should be called after 2881 // those for RHS expression. Even if this will unnecessarily create a block, 2882 // this block will be used at least by the full expression. 2883 autoCreateBlock(); 2884 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2885 if (badCFG) 2886 return NULL; 2887 2888 Succ = ConfluenceBlock; 2889 Block = NULL; 2890 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2891 2892 if (RHSBlock) { 2893 if (badCFG) 2894 return NULL; 2895 2896 // If RHS expression did produce destructors we need to connect created 2897 // blocks to CFG in same manner as for binary operator itself. 2898 CFGBlock *LHSBlock = createBlock(false); 2899 LHSBlock->setTerminator(CFGTerminator(E, true)); 2900 2901 // For binary operator LHS block is before RHS in list of predecessors 2902 // of ConfluenceBlock. 2903 std::reverse(ConfluenceBlock->pred_begin(), 2904 ConfluenceBlock->pred_end()); 2905 2906 // See if this is a known constant. 2907 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2908 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2909 KnownVal.negate(); 2910 2911 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2912 // itself. 2913 if (E->getOpcode() == BO_LOr) { 2914 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2915 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2916 } else { 2917 assert (E->getOpcode() == BO_LAnd); 2918 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2919 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2920 } 2921 2922 Block = LHSBlock; 2923 return LHSBlock; 2924 } 2925 2926 Block = ConfluenceBlock; 2927 return ConfluenceBlock; 2928 } 2929 2930 if (E->isAssignmentOp()) { 2931 // For assignment operator (=) LHS expression is visited 2932 // before RHS expression. For destructors visit them in reverse order. 2933 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2934 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2935 return LHSBlock ? LHSBlock : RHSBlock; 2936 } 2937 2938 // For any other binary operator RHS expression is visited before 2939 // LHS expression (order of children). For destructors visit them in reverse 2940 // order. 2941 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2942 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2943 return RHSBlock ? RHSBlock : LHSBlock; 2944} 2945 2946CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2947 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2948 // First add destructors for temporaries in subexpression. 2949 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2950 if (!BindToTemporary) { 2951 // If lifetime of temporary is not prolonged (by assigning to constant 2952 // reference) add destructor for it. 2953 2954 // If the destructor is marked as a no-return destructor, we need to create 2955 // a new block for the destructor which does not have as a successor 2956 // anything built thus far. Control won't flow out of this block. 2957 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 2958 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 2959 Block = createNoReturnBlock(); 2960 else 2961 autoCreateBlock(); 2962 2963 appendTemporaryDtor(Block, E); 2964 B = Block; 2965 } 2966 return B; 2967} 2968 2969CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2970 AbstractConditionalOperator *E, bool BindToTemporary) { 2971 // First add destructors for condition expression. Even if this will 2972 // unnecessarily create a block, this block will be used at least by the full 2973 // expression. 2974 autoCreateBlock(); 2975 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2976 if (badCFG) 2977 return NULL; 2978 if (BinaryConditionalOperator *BCO 2979 = dyn_cast<BinaryConditionalOperator>(E)) { 2980 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2981 if (badCFG) 2982 return NULL; 2983 } 2984 2985 // Try to add block with destructors for LHS expression. 2986 CFGBlock *LHSBlock = NULL; 2987 Succ = ConfluenceBlock; 2988 Block = NULL; 2989 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2990 if (badCFG) 2991 return NULL; 2992 2993 // Try to add block with destructors for RHS expression; 2994 Succ = ConfluenceBlock; 2995 Block = NULL; 2996 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2997 BindToTemporary); 2998 if (badCFG) 2999 return NULL; 3000 3001 if (!RHSBlock && !LHSBlock) { 3002 // If neither LHS nor RHS expression had temporaries to destroy don't create 3003 // more blocks. 3004 Block = ConfluenceBlock; 3005 return Block; 3006 } 3007 3008 Block = createBlock(false); 3009 Block->setTerminator(CFGTerminator(E, true)); 3010 3011 // See if this is a known constant. 3012 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 3013 3014 if (LHSBlock) { 3015 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 3016 } else if (KnownVal.isFalse()) { 3017 addSuccessor(Block, NULL); 3018 } else { 3019 addSuccessor(Block, ConfluenceBlock); 3020 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 3021 } 3022 3023 if (!RHSBlock) 3024 RHSBlock = ConfluenceBlock; 3025 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 3026 3027 return Block; 3028} 3029 3030} // end anonymous namespace 3031 3032/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 3033/// no successors or predecessors. If this is the first block created in the 3034/// CFG, it is automatically set to be the Entry and Exit of the CFG. 3035CFGBlock *CFG::createBlock() { 3036 bool first_block = begin() == end(); 3037 3038 // Create the block. 3039 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 3040 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this); 3041 Blocks.push_back(Mem, BlkBVC); 3042 3043 // If this is the first block, set it as the Entry and Exit. 3044 if (first_block) 3045 Entry = Exit = &back(); 3046 3047 // Return the block. 3048 return &back(); 3049} 3050 3051/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 3052/// CFG is returned to the caller. 3053CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 3054 const BuildOptions &BO) { 3055 CFGBuilder Builder(C, BO); 3056 return Builder.buildCFG(D, Statement); 3057} 3058 3059const CXXDestructorDecl * 3060CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 3061 switch (getKind()) { 3062 case CFGElement::Invalid: 3063 case CFGElement::Statement: 3064 case CFGElement::Initializer: 3065 llvm_unreachable("getDestructorDecl should only be used with " 3066 "ImplicitDtors"); 3067 case CFGElement::AutomaticObjectDtor: { 3068 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 3069 QualType ty = var->getType(); 3070 ty = ty.getNonReferenceType(); 3071 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3072 ty = arrayType->getElementType(); 3073 } 3074 const RecordType *recordType = ty->getAs<RecordType>(); 3075 const CXXRecordDecl *classDecl = 3076 cast<CXXRecordDecl>(recordType->getDecl()); 3077 return classDecl->getDestructor(); 3078 } 3079 case CFGElement::TemporaryDtor: { 3080 const CXXBindTemporaryExpr *bindExpr = 3081 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 3082 const CXXTemporary *temp = bindExpr->getTemporary(); 3083 return temp->getDestructor(); 3084 } 3085 case CFGElement::BaseDtor: 3086 case CFGElement::MemberDtor: 3087 3088 // Not yet supported. 3089 return 0; 3090 } 3091 llvm_unreachable("getKind() returned bogus value"); 3092} 3093 3094bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3095 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 3096 QualType ty = cdecl->getType(); 3097 return cast<FunctionType>(ty)->getNoReturnAttr(); 3098 } 3099 return false; 3100} 3101 3102//===----------------------------------------------------------------------===// 3103// CFG: Queries for BlkExprs. 3104//===----------------------------------------------------------------------===// 3105 3106namespace { 3107 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3108} 3109 3110static void FindSubExprAssignments(const Stmt *S, 3111 llvm::SmallPtrSet<const Expr*,50>& Set) { 3112 if (!S) 3113 return; 3114 3115 for (Stmt::const_child_range I = S->children(); I; ++I) { 3116 const Stmt *child = *I; 3117 if (!child) 3118 continue; 3119 3120 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3121 if (B->isAssignmentOp()) Set.insert(B); 3122 3123 FindSubExprAssignments(child, Set); 3124 } 3125} 3126 3127static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3128 BlkExprMapTy* M = new BlkExprMapTy(); 3129 3130 // Look for assignments that are used as subexpressions. These are the only 3131 // assignments that we want to *possibly* register as a block-level 3132 // expression. Basically, if an assignment occurs both in a subexpression and 3133 // at the block-level, it is a block-level expression. 3134 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3135 3136 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3137 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3138 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3139 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3140 3141 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3142 3143 // Iterate over the statements again on identify the Expr* and Stmt* at the 3144 // block-level that are block-level expressions. 3145 3146 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3147 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3148 if (!CS) 3149 continue; 3150 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3151 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3152 3153 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3154 // Assignment expressions that are not nested within another 3155 // expression are really "statements" whose value is never used by 3156 // another expression. 3157 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3158 continue; 3159 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3160 // Special handling for statement expressions. The last statement in 3161 // the statement expression is also a block-level expr. 3162 const CompoundStmt *C = SE->getSubStmt(); 3163 if (!C->body_empty()) { 3164 const Stmt *Last = C->body_back(); 3165 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3166 Last = LastEx->IgnoreParens(); 3167 unsigned x = M->size(); 3168 (*M)[Last] = x; 3169 } 3170 } 3171 3172 unsigned x = M->size(); 3173 (*M)[Exp] = x; 3174 } 3175 } 3176 3177 // Look at terminators. The condition is a block-level expression. 3178 3179 Stmt *S = (*I)->getTerminatorCondition(); 3180 3181 if (S && M->find(S) == M->end()) { 3182 unsigned x = M->size(); 3183 (*M)[S] = x; 3184 } 3185 } 3186 3187 return M; 3188} 3189 3190CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3191 assert(S != NULL); 3192 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3193 3194 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3195 BlkExprMapTy::iterator I = M->find(S); 3196 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3197} 3198 3199unsigned CFG::getNumBlkExprs() { 3200 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3201 return M->size(); 3202 3203 // We assume callers interested in the number of BlkExprs will want 3204 // the map constructed if it doesn't already exist. 3205 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3206 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3207} 3208 3209//===----------------------------------------------------------------------===// 3210// Filtered walking of the CFG. 3211//===----------------------------------------------------------------------===// 3212 3213bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3214 const CFGBlock *From, const CFGBlock *To) { 3215 3216 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3217 // If the 'To' has no label or is labeled but the label isn't a 3218 // CaseStmt then filter this edge. 3219 if (const SwitchStmt *S = 3220 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3221 if (S->isAllEnumCasesCovered()) { 3222 const Stmt *L = To->getLabel(); 3223 if (!L || !isa<CaseStmt>(L)) 3224 return true; 3225 } 3226 } 3227 } 3228 3229 return false; 3230} 3231 3232//===----------------------------------------------------------------------===// 3233// Cleanup: CFG dstor. 3234//===----------------------------------------------------------------------===// 3235 3236CFG::~CFG() { 3237 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3238} 3239 3240//===----------------------------------------------------------------------===// 3241// CFG pretty printing 3242//===----------------------------------------------------------------------===// 3243 3244namespace { 3245 3246class StmtPrinterHelper : public PrinterHelper { 3247 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3248 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3249 StmtMapTy StmtMap; 3250 DeclMapTy DeclMap; 3251 signed currentBlock; 3252 unsigned currentStmt; 3253 const LangOptions &LangOpts; 3254public: 3255 3256 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3257 : currentBlock(0), currentStmt(0), LangOpts(LO) 3258 { 3259 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3260 unsigned j = 1; 3261 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3262 BI != BEnd; ++BI, ++j ) { 3263 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3264 const Stmt *stmt= SE->getStmt(); 3265 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3266 StmtMap[stmt] = P; 3267 3268 switch (stmt->getStmtClass()) { 3269 case Stmt::DeclStmtClass: 3270 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3271 break; 3272 case Stmt::IfStmtClass: { 3273 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3274 if (var) 3275 DeclMap[var] = P; 3276 break; 3277 } 3278 case Stmt::ForStmtClass: { 3279 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3280 if (var) 3281 DeclMap[var] = P; 3282 break; 3283 } 3284 case Stmt::WhileStmtClass: { 3285 const VarDecl *var = 3286 cast<WhileStmt>(stmt)->getConditionVariable(); 3287 if (var) 3288 DeclMap[var] = P; 3289 break; 3290 } 3291 case Stmt::SwitchStmtClass: { 3292 const VarDecl *var = 3293 cast<SwitchStmt>(stmt)->getConditionVariable(); 3294 if (var) 3295 DeclMap[var] = P; 3296 break; 3297 } 3298 case Stmt::CXXCatchStmtClass: { 3299 const VarDecl *var = 3300 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3301 if (var) 3302 DeclMap[var] = P; 3303 break; 3304 } 3305 default: 3306 break; 3307 } 3308 } 3309 } 3310 } 3311 } 3312 3313 3314 virtual ~StmtPrinterHelper() {} 3315 3316 const LangOptions &getLangOpts() const { return LangOpts; } 3317 void setBlockID(signed i) { currentBlock = i; } 3318 void setStmtID(unsigned i) { currentStmt = i; } 3319 3320 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3321 StmtMapTy::iterator I = StmtMap.find(S); 3322 3323 if (I == StmtMap.end()) 3324 return false; 3325 3326 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3327 && I->second.second == currentStmt) { 3328 return false; 3329 } 3330 3331 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3332 return true; 3333 } 3334 3335 bool handleDecl(const Decl *D, raw_ostream &OS) { 3336 DeclMapTy::iterator I = DeclMap.find(D); 3337 3338 if (I == DeclMap.end()) 3339 return false; 3340 3341 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3342 && I->second.second == currentStmt) { 3343 return false; 3344 } 3345 3346 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3347 return true; 3348 } 3349}; 3350} // end anonymous namespace 3351 3352 3353namespace { 3354class CFGBlockTerminatorPrint 3355 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3356 3357 raw_ostream &OS; 3358 StmtPrinterHelper* Helper; 3359 PrintingPolicy Policy; 3360public: 3361 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3362 const PrintingPolicy &Policy) 3363 : OS(os), Helper(helper), Policy(Policy) {} 3364 3365 void VisitIfStmt(IfStmt *I) { 3366 OS << "if "; 3367 I->getCond()->printPretty(OS,Helper,Policy); 3368 } 3369 3370 // Default case. 3371 void VisitStmt(Stmt *Terminator) { 3372 Terminator->printPretty(OS, Helper, Policy); 3373 } 3374 3375 void VisitForStmt(ForStmt *F) { 3376 OS << "for (" ; 3377 if (F->getInit()) 3378 OS << "..."; 3379 OS << "; "; 3380 if (Stmt *C = F->getCond()) 3381 C->printPretty(OS, Helper, Policy); 3382 OS << "; "; 3383 if (F->getInc()) 3384 OS << "..."; 3385 OS << ")"; 3386 } 3387 3388 void VisitWhileStmt(WhileStmt *W) { 3389 OS << "while " ; 3390 if (Stmt *C = W->getCond()) 3391 C->printPretty(OS, Helper, Policy); 3392 } 3393 3394 void VisitDoStmt(DoStmt *D) { 3395 OS << "do ... while "; 3396 if (Stmt *C = D->getCond()) 3397 C->printPretty(OS, Helper, Policy); 3398 } 3399 3400 void VisitSwitchStmt(SwitchStmt *Terminator) { 3401 OS << "switch "; 3402 Terminator->getCond()->printPretty(OS, Helper, Policy); 3403 } 3404 3405 void VisitCXXTryStmt(CXXTryStmt *CS) { 3406 OS << "try ..."; 3407 } 3408 3409 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3410 C->getCond()->printPretty(OS, Helper, Policy); 3411 OS << " ? ... : ..."; 3412 } 3413 3414 void VisitChooseExpr(ChooseExpr *C) { 3415 OS << "__builtin_choose_expr( "; 3416 C->getCond()->printPretty(OS, Helper, Policy); 3417 OS << " )"; 3418 } 3419 3420 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3421 OS << "goto *"; 3422 I->getTarget()->printPretty(OS, Helper, Policy); 3423 } 3424 3425 void VisitBinaryOperator(BinaryOperator* B) { 3426 if (!B->isLogicalOp()) { 3427 VisitExpr(B); 3428 return; 3429 } 3430 3431 B->getLHS()->printPretty(OS, Helper, Policy); 3432 3433 switch (B->getOpcode()) { 3434 case BO_LOr: 3435 OS << " || ..."; 3436 return; 3437 case BO_LAnd: 3438 OS << " && ..."; 3439 return; 3440 default: 3441 llvm_unreachable("Invalid logical operator."); 3442 } 3443 } 3444 3445 void VisitExpr(Expr *E) { 3446 E->printPretty(OS, Helper, Policy); 3447 } 3448}; 3449} // end anonymous namespace 3450 3451static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3452 const CFGElement &E) { 3453 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3454 const Stmt *S = CS->getStmt(); 3455 3456 if (Helper) { 3457 3458 // special printing for statement-expressions. 3459 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3460 const CompoundStmt *Sub = SE->getSubStmt(); 3461 3462 if (Sub->children()) { 3463 OS << "({ ... ; "; 3464 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3465 OS << " })\n"; 3466 return; 3467 } 3468 } 3469 // special printing for comma expressions. 3470 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3471 if (B->getOpcode() == BO_Comma) { 3472 OS << "... , "; 3473 Helper->handledStmt(B->getRHS(),OS); 3474 OS << '\n'; 3475 return; 3476 } 3477 } 3478 } 3479 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3480 3481 if (isa<CXXOperatorCallExpr>(S)) { 3482 OS << " (OperatorCall)"; 3483 } 3484 else if (isa<CXXBindTemporaryExpr>(S)) { 3485 OS << " (BindTemporary)"; 3486 } 3487 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) { 3488 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")"; 3489 } 3490 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) { 3491 OS << " (" << CE->getStmtClassName() << ", " 3492 << CE->getCastKindName() 3493 << ", " << CE->getType().getAsString() 3494 << ")"; 3495 } 3496 3497 // Expressions need a newline. 3498 if (isa<Expr>(S)) 3499 OS << '\n'; 3500 3501 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3502 const CXXCtorInitializer *I = IE->getInitializer(); 3503 if (I->isBaseInitializer()) 3504 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3505 else OS << I->getAnyMember()->getName(); 3506 3507 OS << "("; 3508 if (Expr *IE = I->getInit()) 3509 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3510 OS << ")"; 3511 3512 if (I->isBaseInitializer()) 3513 OS << " (Base initializer)\n"; 3514 else OS << " (Member initializer)\n"; 3515 3516 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3517 const VarDecl *VD = DE->getVarDecl(); 3518 Helper->handleDecl(VD, OS); 3519 3520 const Type* T = VD->getType().getTypePtr(); 3521 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3522 T = RT->getPointeeType().getTypePtr(); 3523 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3524 T = ET; 3525 3526 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3527 OS << " (Implicit destructor)\n"; 3528 3529 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3530 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3531 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3532 OS << " (Base object destructor)\n"; 3533 3534 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3535 const FieldDecl *FD = ME->getFieldDecl(); 3536 3537 const Type *T = FD->getType().getTypePtr(); 3538 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3539 T = ET; 3540 3541 OS << "this->" << FD->getName(); 3542 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3543 OS << " (Member object destructor)\n"; 3544 3545 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3546 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3547 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3548 OS << " (Temporary object destructor)\n"; 3549 } 3550} 3551 3552static void print_block(raw_ostream &OS, const CFG* cfg, 3553 const CFGBlock &B, 3554 StmtPrinterHelper* Helper, bool print_edges, 3555 bool ShowColors) { 3556 3557 if (Helper) 3558 Helper->setBlockID(B.getBlockID()); 3559 3560 // Print the header. 3561 if (ShowColors) 3562 OS.changeColor(raw_ostream::YELLOW, true); 3563 3564 OS << "\n [B" << B.getBlockID(); 3565 3566 if (&B == &cfg->getEntry()) 3567 OS << " (ENTRY)]\n"; 3568 else if (&B == &cfg->getExit()) 3569 OS << " (EXIT)]\n"; 3570 else if (&B == cfg->getIndirectGotoBlock()) 3571 OS << " (INDIRECT GOTO DISPATCH)]\n"; 3572 else 3573 OS << "]\n"; 3574 3575 if (ShowColors) 3576 OS.resetColor(); 3577 3578 // Print the label of this block. 3579 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3580 3581 if (print_edges) 3582 OS << " "; 3583 3584 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3585 OS << L->getName(); 3586 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3587 OS << "case "; 3588 C->getLHS()->printPretty(OS, Helper, 3589 PrintingPolicy(Helper->getLangOpts())); 3590 if (C->getRHS()) { 3591 OS << " ... "; 3592 C->getRHS()->printPretty(OS, Helper, 3593 PrintingPolicy(Helper->getLangOpts())); 3594 } 3595 } else if (isa<DefaultStmt>(Label)) 3596 OS << "default"; 3597 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3598 OS << "catch ("; 3599 if (CS->getExceptionDecl()) 3600 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3601 0); 3602 else 3603 OS << "..."; 3604 OS << ")"; 3605 3606 } else 3607 llvm_unreachable("Invalid label statement in CFGBlock."); 3608 3609 OS << ":\n"; 3610 } 3611 3612 // Iterate through the statements in the block and print them. 3613 unsigned j = 1; 3614 3615 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3616 I != E ; ++I, ++j ) { 3617 3618 // Print the statement # in the basic block and the statement itself. 3619 if (print_edges) 3620 OS << " "; 3621 3622 OS << llvm::format("%3d", j) << ": "; 3623 3624 if (Helper) 3625 Helper->setStmtID(j); 3626 3627 print_elem(OS, Helper, *I); 3628 } 3629 3630 // Print the terminator of this block. 3631 if (B.getTerminator()) { 3632 if (ShowColors) 3633 OS.changeColor(raw_ostream::GREEN); 3634 3635 OS << " T: "; 3636 3637 if (Helper) Helper->setBlockID(-1); 3638 3639 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3640 PrintingPolicy(Helper->getLangOpts())); 3641 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3642 OS << '\n'; 3643 3644 if (ShowColors) 3645 OS.resetColor(); 3646 } 3647 3648 if (print_edges) { 3649 // Print the predecessors of this block. 3650 if (!B.pred_empty()) { 3651 const raw_ostream::Colors Color = raw_ostream::BLUE; 3652 if (ShowColors) 3653 OS.changeColor(Color); 3654 OS << " Preds " ; 3655 if (ShowColors) 3656 OS.resetColor(); 3657 OS << '(' << B.pred_size() << "):"; 3658 unsigned i = 0; 3659 3660 if (ShowColors) 3661 OS.changeColor(Color); 3662 3663 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3664 I != E; ++I, ++i) { 3665 3666 if (i == 8 || (i-8) == 0) 3667 OS << "\n "; 3668 3669 OS << " B" << (*I)->getBlockID(); 3670 } 3671 3672 if (ShowColors) 3673 OS.resetColor(); 3674 3675 OS << '\n'; 3676 } 3677 3678 // Print the successors of this block. 3679 if (!B.succ_empty()) { 3680 const raw_ostream::Colors Color = raw_ostream::MAGENTA; 3681 if (ShowColors) 3682 OS.changeColor(Color); 3683 OS << " Succs "; 3684 if (ShowColors) 3685 OS.resetColor(); 3686 OS << '(' << B.succ_size() << "):"; 3687 unsigned i = 0; 3688 3689 if (ShowColors) 3690 OS.changeColor(Color); 3691 3692 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3693 I != E; ++I, ++i) { 3694 3695 if (i == 8 || (i-8) % 10 == 0) 3696 OS << "\n "; 3697 3698 if (*I) 3699 OS << " B" << (*I)->getBlockID(); 3700 else 3701 OS << " NULL"; 3702 } 3703 3704 if (ShowColors) 3705 OS.resetColor(); 3706 OS << '\n'; 3707 } 3708 } 3709} 3710 3711 3712/// dump - A simple pretty printer of a CFG that outputs to stderr. 3713void CFG::dump(const LangOptions &LO, bool ShowColors) const { 3714 print(llvm::errs(), LO, ShowColors); 3715} 3716 3717/// print - A simple pretty printer of a CFG that outputs to an ostream. 3718void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const { 3719 StmtPrinterHelper Helper(this, LO); 3720 3721 // Print the entry block. 3722 print_block(OS, this, getEntry(), &Helper, true, ShowColors); 3723 3724 // Iterate through the CFGBlocks and print them one by one. 3725 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3726 // Skip the entry block, because we already printed it. 3727 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3728 continue; 3729 3730 print_block(OS, this, **I, &Helper, true, ShowColors); 3731 } 3732 3733 // Print the exit block. 3734 print_block(OS, this, getExit(), &Helper, true, ShowColors); 3735 OS << '\n'; 3736 OS.flush(); 3737} 3738 3739/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3740void CFGBlock::dump(const CFG* cfg, const LangOptions &LO, 3741 bool ShowColors) const { 3742 print(llvm::errs(), cfg, LO, ShowColors); 3743} 3744 3745/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3746/// Generally this will only be called from CFG::print. 3747void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3748 const LangOptions &LO, bool ShowColors) const { 3749 StmtPrinterHelper Helper(cfg, LO); 3750 print_block(OS, cfg, *this, &Helper, true, ShowColors); 3751 OS << '\n'; 3752} 3753 3754/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3755void CFGBlock::printTerminator(raw_ostream &OS, 3756 const LangOptions &LO) const { 3757 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3758 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3759} 3760 3761Stmt *CFGBlock::getTerminatorCondition() { 3762 Stmt *Terminator = this->Terminator; 3763 if (!Terminator) 3764 return NULL; 3765 3766 Expr *E = NULL; 3767 3768 switch (Terminator->getStmtClass()) { 3769 default: 3770 break; 3771 3772 case Stmt::ForStmtClass: 3773 E = cast<ForStmt>(Terminator)->getCond(); 3774 break; 3775 3776 case Stmt::WhileStmtClass: 3777 E = cast<WhileStmt>(Terminator)->getCond(); 3778 break; 3779 3780 case Stmt::DoStmtClass: 3781 E = cast<DoStmt>(Terminator)->getCond(); 3782 break; 3783 3784 case Stmt::IfStmtClass: 3785 E = cast<IfStmt>(Terminator)->getCond(); 3786 break; 3787 3788 case Stmt::ChooseExprClass: 3789 E = cast<ChooseExpr>(Terminator)->getCond(); 3790 break; 3791 3792 case Stmt::IndirectGotoStmtClass: 3793 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3794 break; 3795 3796 case Stmt::SwitchStmtClass: 3797 E = cast<SwitchStmt>(Terminator)->getCond(); 3798 break; 3799 3800 case Stmt::BinaryConditionalOperatorClass: 3801 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3802 break; 3803 3804 case Stmt::ConditionalOperatorClass: 3805 E = cast<ConditionalOperator>(Terminator)->getCond(); 3806 break; 3807 3808 case Stmt::BinaryOperatorClass: // '&&' and '||' 3809 E = cast<BinaryOperator>(Terminator)->getLHS(); 3810 break; 3811 3812 case Stmt::ObjCForCollectionStmtClass: 3813 return Terminator; 3814 } 3815 3816 return E ? E->IgnoreParens() : NULL; 3817} 3818 3819//===----------------------------------------------------------------------===// 3820// CFG Graphviz Visualization 3821//===----------------------------------------------------------------------===// 3822 3823 3824#ifndef NDEBUG 3825static StmtPrinterHelper* GraphHelper; 3826#endif 3827 3828void CFG::viewCFG(const LangOptions &LO) const { 3829#ifndef NDEBUG 3830 StmtPrinterHelper H(this, LO); 3831 GraphHelper = &H; 3832 llvm::ViewGraph(this,"CFG"); 3833 GraphHelper = NULL; 3834#endif 3835} 3836 3837namespace llvm { 3838template<> 3839struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3840 3841 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3842 3843 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 3844 3845#ifndef NDEBUG 3846 std::string OutSStr; 3847 llvm::raw_string_ostream Out(OutSStr); 3848 print_block(Out,Graph, *Node, GraphHelper, false, false); 3849 std::string& OutStr = Out.str(); 3850 3851 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3852 3853 // Process string output to make it nicer... 3854 for (unsigned i = 0; i != OutStr.length(); ++i) 3855 if (OutStr[i] == '\n') { // Left justify 3856 OutStr[i] = '\\'; 3857 OutStr.insert(OutStr.begin()+i+1, 'l'); 3858 } 3859 3860 return OutStr; 3861#else 3862 return ""; 3863#endif 3864 } 3865}; 3866} // end namespace llvm 3867