CFG.cpp revision 72b20ff76a9070c1a481331e857aa825ae37c97f
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 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 755 if (!CD->hasTrivialDestructor()) { 756 autoCreateBlock(); 757 appendBaseDtor(Block, BI); 758 } 759 } 760 } 761 762 // First destroy member objects. 763 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 764 FE = RD->field_end(); FI != FE; ++FI) { 765 // Check for constant size array. Set type to array element type. 766 QualType QT = FI->getType(); 767 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 768 if (AT->getSize() == 0) 769 continue; 770 QT = AT->getElementType(); 771 } 772 773 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 774 if (!CD->hasTrivialDestructor()) { 775 autoCreateBlock(); 776 appendMemberDtor(Block, *FI); 777 } 778 } 779} 780 781/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 782/// way return valid LocalScope object. 783LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 784 if (!Scope) { 785 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 786 Scope = alloc.Allocate<LocalScope>(); 787 BumpVectorContext ctx(alloc); 788 new (Scope) LocalScope(ctx, ScopePos); 789 } 790 return Scope; 791} 792 793/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 794/// that should create implicit scope (e.g. if/else substatements). 795void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 796 if (!BuildOpts.AddImplicitDtors) 797 return; 798 799 LocalScope *Scope = 0; 800 801 // For compound statement we will be creating explicit scope. 802 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 803 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 804 ; BI != BE; ++BI) { 805 Stmt *SI = (*BI)->stripLabelLikeStatements(); 806 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 807 Scope = addLocalScopeForDeclStmt(DS, Scope); 808 } 809 return; 810 } 811 812 // For any other statement scope will be implicit and as such will be 813 // interesting only for DeclStmt. 814 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 815 addLocalScopeForDeclStmt(DS); 816} 817 818/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 819/// reuse Scope if not NULL. 820LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 821 LocalScope* Scope) { 822 if (!BuildOpts.AddImplicitDtors) 823 return Scope; 824 825 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 826 ; DI != DE; ++DI) { 827 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 828 Scope = addLocalScopeForVarDecl(VD, Scope); 829 } 830 return Scope; 831} 832 833/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 834/// create add scope for automatic objects and temporary objects bound to 835/// const reference. Will reuse Scope if not NULL. 836LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 837 LocalScope* Scope) { 838 if (!BuildOpts.AddImplicitDtors) 839 return Scope; 840 841 // Check if variable is local. 842 switch (VD->getStorageClass()) { 843 case SC_None: 844 case SC_Auto: 845 case SC_Register: 846 break; 847 default: return Scope; 848 } 849 850 // Check for const references bound to temporary. Set type to pointee. 851 QualType QT = VD->getType(); 852 if (QT.getTypePtr()->isReferenceType()) { 853 if (!VD->extendsLifetimeOfTemporary()) 854 return Scope; 855 856 QT = getReferenceInitTemporaryType(*Context, VD->getInit()); 857 } 858 859 // Check for constant size array. Set type to array element type. 860 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 861 if (AT->getSize() == 0) 862 return Scope; 863 QT = AT->getElementType(); 864 } 865 866 // Check if type is a C++ class with non-trivial destructor. 867 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 868 if (!CD->hasTrivialDestructor()) { 869 // Add the variable to scope 870 Scope = createOrReuseLocalScope(Scope); 871 Scope->addVar(VD); 872 ScopePos = Scope->begin(); 873 } 874 return Scope; 875} 876 877/// addLocalScopeAndDtors - For given statement add local scope for it and 878/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 879void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 880 if (!BuildOpts.AddImplicitDtors) 881 return; 882 883 LocalScope::const_iterator scopeBeginPos = ScopePos; 884 addLocalScopeForStmt(S); 885 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 886} 887 888/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 889/// variables with automatic storage duration to CFGBlock's elements vector. 890/// Elements will be prepended to physical beginning of the vector which 891/// happens to be logical end. Use blocks terminator as statement that specifies 892/// destructors call site. 893/// FIXME: This mechanism for adding automatic destructors doesn't handle 894/// no-return destructors properly. 895void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 896 LocalScope::const_iterator B, LocalScope::const_iterator E) { 897 BumpVectorContext &C = cfg->getBumpVectorContext(); 898 CFGBlock::iterator InsertPos 899 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 900 for (LocalScope::const_iterator I = B; I != E; ++I) 901 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 902 Blk->getTerminator()); 903} 904 905/// Visit - Walk the subtree of a statement and add extra 906/// blocks for ternary operators, &&, and ||. We also process "," and 907/// DeclStmts (which may contain nested control-flow). 908CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 909 if (!S) { 910 badCFG = true; 911 return 0; 912 } 913 914 if (Expr *E = dyn_cast<Expr>(S)) 915 S = E->IgnoreParens(); 916 917 switch (S->getStmtClass()) { 918 default: 919 return VisitStmt(S, asc); 920 921 case Stmt::AddrLabelExprClass: 922 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 923 924 case Stmt::BinaryConditionalOperatorClass: 925 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 926 927 case Stmt::BinaryOperatorClass: 928 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 929 930 case Stmt::BlockExprClass: 931 return VisitBlockExpr(cast<BlockExpr>(S), asc); 932 933 case Stmt::BreakStmtClass: 934 return VisitBreakStmt(cast<BreakStmt>(S)); 935 936 case Stmt::CallExprClass: 937 case Stmt::CXXOperatorCallExprClass: 938 case Stmt::CXXMemberCallExprClass: 939 return VisitCallExpr(cast<CallExpr>(S), asc); 940 941 case Stmt::CaseStmtClass: 942 return VisitCaseStmt(cast<CaseStmt>(S)); 943 944 case Stmt::ChooseExprClass: 945 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 946 947 case Stmt::CompoundStmtClass: 948 return VisitCompoundStmt(cast<CompoundStmt>(S)); 949 950 case Stmt::ConditionalOperatorClass: 951 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 952 953 case Stmt::ContinueStmtClass: 954 return VisitContinueStmt(cast<ContinueStmt>(S)); 955 956 case Stmt::CXXCatchStmtClass: 957 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 958 959 case Stmt::ExprWithCleanupsClass: 960 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 961 962 case Stmt::CXXBindTemporaryExprClass: 963 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 964 965 case Stmt::CXXConstructExprClass: 966 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 967 968 case Stmt::CXXFunctionalCastExprClass: 969 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 970 971 case Stmt::CXXTemporaryObjectExprClass: 972 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 973 974 case Stmt::CXXThrowExprClass: 975 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 976 977 case Stmt::CXXTryStmtClass: 978 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 979 980 case Stmt::CXXForRangeStmtClass: 981 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 982 983 case Stmt::DeclStmtClass: 984 return VisitDeclStmt(cast<DeclStmt>(S)); 985 986 case Stmt::DefaultStmtClass: 987 return VisitDefaultStmt(cast<DefaultStmt>(S)); 988 989 case Stmt::DoStmtClass: 990 return VisitDoStmt(cast<DoStmt>(S)); 991 992 case Stmt::ForStmtClass: 993 return VisitForStmt(cast<ForStmt>(S)); 994 995 case Stmt::GotoStmtClass: 996 return VisitGotoStmt(cast<GotoStmt>(S)); 997 998 case Stmt::IfStmtClass: 999 return VisitIfStmt(cast<IfStmt>(S)); 1000 1001 case Stmt::ImplicitCastExprClass: 1002 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 1003 1004 case Stmt::IndirectGotoStmtClass: 1005 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 1006 1007 case Stmt::LabelStmtClass: 1008 return VisitLabelStmt(cast<LabelStmt>(S)); 1009 1010 case Stmt::MemberExprClass: 1011 return VisitMemberExpr(cast<MemberExpr>(S), asc); 1012 1013 case Stmt::NullStmtClass: 1014 return Block; 1015 1016 case Stmt::ObjCAtCatchStmtClass: 1017 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 1018 1019 case Stmt::ObjCAtSynchronizedStmtClass: 1020 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 1021 1022 case Stmt::ObjCAtThrowStmtClass: 1023 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 1024 1025 case Stmt::ObjCAtTryStmtClass: 1026 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 1027 1028 case Stmt::ObjCForCollectionStmtClass: 1029 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 1030 1031 case Stmt::OpaqueValueExprClass: 1032 return Block; 1033 1034 case Stmt::PseudoObjectExprClass: 1035 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S)); 1036 1037 case Stmt::ReturnStmtClass: 1038 return VisitReturnStmt(cast<ReturnStmt>(S)); 1039 1040 case Stmt::UnaryExprOrTypeTraitExprClass: 1041 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 1042 asc); 1043 1044 case Stmt::StmtExprClass: 1045 return VisitStmtExpr(cast<StmtExpr>(S), asc); 1046 1047 case Stmt::SwitchStmtClass: 1048 return VisitSwitchStmt(cast<SwitchStmt>(S)); 1049 1050 case Stmt::UnaryOperatorClass: 1051 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 1052 1053 case Stmt::WhileStmtClass: 1054 return VisitWhileStmt(cast<WhileStmt>(S)); 1055 } 1056} 1057 1058CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1059 if (asc.alwaysAdd(*this, S)) { 1060 autoCreateBlock(); 1061 appendStmt(Block, S); 1062 } 1063 1064 return VisitChildren(S); 1065} 1066 1067/// VisitChildren - Visit the children of a Stmt. 1068CFGBlock *CFGBuilder::VisitChildren(Stmt *Terminator) { 1069 CFGBlock *lastBlock = Block; 1070 for (Stmt::child_range I = Terminator->children(); I; ++I) 1071 if (Stmt *child = *I) 1072 if (CFGBlock *b = Visit(child)) 1073 lastBlock = b; 1074 1075 return lastBlock; 1076} 1077 1078CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1079 AddStmtChoice asc) { 1080 AddressTakenLabels.insert(A->getLabel()); 1081 1082 if (asc.alwaysAdd(*this, A)) { 1083 autoCreateBlock(); 1084 appendStmt(Block, A); 1085 } 1086 1087 return Block; 1088} 1089 1090CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1091 AddStmtChoice asc) { 1092 if (asc.alwaysAdd(*this, U)) { 1093 autoCreateBlock(); 1094 appendStmt(Block, U); 1095 } 1096 1097 return Visit(U->getSubExpr(), AddStmtChoice()); 1098} 1099 1100CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1101 AddStmtChoice asc) { 1102 if (B->isLogicalOp()) { // && or || 1103 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1104 appendStmt(ConfluenceBlock, B); 1105 1106 if (badCFG) 1107 return 0; 1108 1109 // create the block evaluating the LHS 1110 CFGBlock *LHSBlock = createBlock(false); 1111 LHSBlock->setTerminator(B); 1112 1113 // create the block evaluating the RHS 1114 Succ = ConfluenceBlock; 1115 Block = NULL; 1116 CFGBlock *RHSBlock = addStmt(B->getRHS()); 1117 1118 if (RHSBlock) { 1119 if (badCFG) 1120 return 0; 1121 } else { 1122 // Create an empty block for cases where the RHS doesn't require 1123 // any explicit statements in the CFG. 1124 RHSBlock = createBlock(); 1125 } 1126 1127 // See if this is a known constant. 1128 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1129 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1130 KnownVal.negate(); 1131 1132 // Now link the LHSBlock with RHSBlock. 1133 if (B->getOpcode() == BO_LOr) { 1134 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1135 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1136 } else { 1137 assert(B->getOpcode() == BO_LAnd); 1138 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1139 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1140 } 1141 1142 // Generate the blocks for evaluating the LHS. 1143 Block = LHSBlock; 1144 return addStmt(B->getLHS()); 1145 } 1146 1147 if (B->getOpcode() == BO_Comma) { // , 1148 autoCreateBlock(); 1149 appendStmt(Block, B); 1150 addStmt(B->getRHS()); 1151 return addStmt(B->getLHS()); 1152 } 1153 1154 if (B->isAssignmentOp()) { 1155 if (asc.alwaysAdd(*this, B)) { 1156 autoCreateBlock(); 1157 appendStmt(Block, B); 1158 } 1159 Visit(B->getLHS()); 1160 return Visit(B->getRHS()); 1161 } 1162 1163 if (asc.alwaysAdd(*this, B)) { 1164 autoCreateBlock(); 1165 appendStmt(Block, B); 1166 } 1167 1168 CFGBlock *RBlock = Visit(B->getRHS()); 1169 CFGBlock *LBlock = Visit(B->getLHS()); 1170 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1171 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1172 // return RBlock. Otherwise we'll incorrectly return NULL. 1173 return (LBlock ? LBlock : RBlock); 1174} 1175 1176CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1177 if (asc.alwaysAdd(*this, E)) { 1178 autoCreateBlock(); 1179 appendStmt(Block, E); 1180 } 1181 return Block; 1182} 1183 1184CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1185 // "break" is a control-flow statement. Thus we stop processing the current 1186 // block. 1187 if (badCFG) 1188 return 0; 1189 1190 // Now create a new block that ends with the break statement. 1191 Block = createBlock(false); 1192 Block->setTerminator(B); 1193 1194 // If there is no target for the break, then we are looking at an incomplete 1195 // AST. This means that the CFG cannot be constructed. 1196 if (BreakJumpTarget.block) { 1197 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1198 addSuccessor(Block, BreakJumpTarget.block); 1199 } else 1200 badCFG = true; 1201 1202 1203 return Block; 1204} 1205 1206static bool CanThrow(Expr *E, ASTContext &Ctx) { 1207 QualType Ty = E->getType(); 1208 if (Ty->isFunctionPointerType()) 1209 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1210 else if (Ty->isBlockPointerType()) 1211 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1212 1213 const FunctionType *FT = Ty->getAs<FunctionType>(); 1214 if (FT) { 1215 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1216 if (Proto->isNothrow(Ctx)) 1217 return false; 1218 } 1219 return true; 1220} 1221 1222CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1223 // Compute the callee type. 1224 QualType calleeType = C->getCallee()->getType(); 1225 if (calleeType == Context->BoundMemberTy) { 1226 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1227 1228 // We should only get a null bound type if processing a dependent 1229 // CFG. Recover by assuming nothing. 1230 if (!boundType.isNull()) calleeType = boundType; 1231 } 1232 1233 // If this is a call to a no-return function, this stops the block here. 1234 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1235 1236 bool AddEHEdge = false; 1237 1238 // Languages without exceptions are assumed to not throw. 1239 if (Context->getLangOptions().Exceptions) { 1240 if (BuildOpts.AddEHEdges) 1241 AddEHEdge = true; 1242 } 1243 1244 if (FunctionDecl *FD = C->getDirectCallee()) { 1245 if (FD->hasAttr<NoReturnAttr>()) 1246 NoReturn = true; 1247 if (FD->hasAttr<NoThrowAttr>()) 1248 AddEHEdge = false; 1249 } 1250 1251 if (!CanThrow(C->getCallee(), *Context)) 1252 AddEHEdge = false; 1253 1254 if (!NoReturn && !AddEHEdge) 1255 return VisitStmt(C, asc.withAlwaysAdd(true)); 1256 1257 if (Block) { 1258 Succ = Block; 1259 if (badCFG) 1260 return 0; 1261 } 1262 1263 if (NoReturn) 1264 Block = createNoReturnBlock(); 1265 else 1266 Block = createBlock(); 1267 1268 appendStmt(Block, C); 1269 1270 if (AddEHEdge) { 1271 // Add exceptional edges. 1272 if (TryTerminatedBlock) 1273 addSuccessor(Block, TryTerminatedBlock); 1274 else 1275 addSuccessor(Block, &cfg->getExit()); 1276 } 1277 1278 return VisitChildren(C); 1279} 1280 1281CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1282 AddStmtChoice asc) { 1283 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1284 appendStmt(ConfluenceBlock, C); 1285 if (badCFG) 1286 return 0; 1287 1288 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1289 Succ = ConfluenceBlock; 1290 Block = NULL; 1291 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1292 if (badCFG) 1293 return 0; 1294 1295 Succ = ConfluenceBlock; 1296 Block = NULL; 1297 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1298 if (badCFG) 1299 return 0; 1300 1301 Block = createBlock(false); 1302 // See if this is a known constant. 1303 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1304 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1305 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1306 Block->setTerminator(C); 1307 return addStmt(C->getCond()); 1308} 1309 1310 1311CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1312 addLocalScopeAndDtors(C); 1313 CFGBlock *LastBlock = Block; 1314 1315 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1316 I != E; ++I ) { 1317 // If we hit a segment of code just containing ';' (NullStmts), we can 1318 // get a null block back. In such cases, just use the LastBlock 1319 if (CFGBlock *newBlock = addStmt(*I)) 1320 LastBlock = newBlock; 1321 1322 if (badCFG) 1323 return NULL; 1324 } 1325 1326 return LastBlock; 1327} 1328 1329CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1330 AddStmtChoice asc) { 1331 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1332 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1333 1334 // Create the confluence block that will "merge" the results of the ternary 1335 // expression. 1336 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1337 appendStmt(ConfluenceBlock, C); 1338 if (badCFG) 1339 return 0; 1340 1341 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1342 1343 // Create a block for the LHS expression if there is an LHS expression. A 1344 // GCC extension allows LHS to be NULL, causing the condition to be the 1345 // value that is returned instead. 1346 // e.g: x ?: y is shorthand for: x ? x : y; 1347 Succ = ConfluenceBlock; 1348 Block = NULL; 1349 CFGBlock *LHSBlock = 0; 1350 const Expr *trueExpr = C->getTrueExpr(); 1351 if (trueExpr != opaqueValue) { 1352 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1353 if (badCFG) 1354 return 0; 1355 Block = NULL; 1356 } 1357 else 1358 LHSBlock = ConfluenceBlock; 1359 1360 // Create the block for the RHS expression. 1361 Succ = ConfluenceBlock; 1362 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1363 if (badCFG) 1364 return 0; 1365 1366 // Create the block that will contain the condition. 1367 Block = createBlock(false); 1368 1369 // See if this is a known constant. 1370 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1371 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1372 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1373 Block->setTerminator(C); 1374 Expr *condExpr = C->getCond(); 1375 1376 if (opaqueValue) { 1377 // Run the condition expression if it's not trivially expressed in 1378 // terms of the opaque value (or if there is no opaque value). 1379 if (condExpr != opaqueValue) 1380 addStmt(condExpr); 1381 1382 // Before that, run the common subexpression if there was one. 1383 // At least one of this or the above will be run. 1384 return addStmt(BCO->getCommon()); 1385 } 1386 1387 return addStmt(condExpr); 1388} 1389 1390CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1391 // Check if the Decl is for an __label__. If so, elide it from the 1392 // CFG entirely. 1393 if (isa<LabelDecl>(*DS->decl_begin())) 1394 return Block; 1395 1396 // This case also handles static_asserts. 1397 if (DS->isSingleDecl()) 1398 return VisitDeclSubExpr(DS); 1399 1400 CFGBlock *B = 0; 1401 1402 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1403 typedef SmallVector<Decl*,10> BufTy; 1404 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1405 1406 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1407 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1408 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1409 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1410 1411 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1412 // automatically freed with the CFG. 1413 DeclGroupRef DG(*I); 1414 Decl *D = *I; 1415 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1416 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1417 1418 // Append the fake DeclStmt to block. 1419 B = VisitDeclSubExpr(DSNew); 1420 } 1421 1422 return B; 1423} 1424 1425/// VisitDeclSubExpr - Utility method to add block-level expressions for 1426/// DeclStmts and initializers in them. 1427CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1428 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1429 Decl *D = DS->getSingleDecl(); 1430 1431 if (isa<StaticAssertDecl>(D)) { 1432 // static_asserts aren't added to the CFG because they do not impact 1433 // runtime semantics. 1434 return Block; 1435 } 1436 1437 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1438 1439 if (!VD) { 1440 autoCreateBlock(); 1441 appendStmt(Block, DS); 1442 return Block; 1443 } 1444 1445 bool IsReference = false; 1446 bool HasTemporaries = false; 1447 1448 // Destructors of temporaries in initialization expression should be called 1449 // after initialization finishes. 1450 Expr *Init = VD->getInit(); 1451 if (Init) { 1452 IsReference = VD->getType()->isReferenceType(); 1453 HasTemporaries = isa<ExprWithCleanups>(Init); 1454 1455 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1456 // Generate destructors for temporaries in initialization expression. 1457 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1458 IsReference); 1459 } 1460 } 1461 1462 autoCreateBlock(); 1463 appendStmt(Block, DS); 1464 1465 if (Init) { 1466 if (HasTemporaries) 1467 // For expression with temporaries go directly to subexpression to omit 1468 // generating destructors for the second time. 1469 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1470 else 1471 Visit(Init); 1472 } 1473 1474 // If the type of VD is a VLA, then we must process its size expressions. 1475 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1476 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1477 Block = addStmt(VA->getSizeExpr()); 1478 1479 // Remove variable from local scope. 1480 if (ScopePos && VD == *ScopePos) 1481 ++ScopePos; 1482 1483 return Block; 1484} 1485 1486CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1487 // We may see an if statement in the middle of a basic block, or it may be the 1488 // first statement we are processing. In either case, we create a new basic 1489 // block. First, we create the blocks for the then...else statements, and 1490 // then we create the block containing the if statement. If we were in the 1491 // middle of a block, we stop processing that block. That block is then the 1492 // implicit successor for the "then" and "else" clauses. 1493 1494 // Save local scope position because in case of condition variable ScopePos 1495 // won't be restored when traversing AST. 1496 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1497 1498 // Create local scope for possible condition variable. 1499 // Store scope position. Add implicit destructor. 1500 if (VarDecl *VD = I->getConditionVariable()) { 1501 LocalScope::const_iterator BeginScopePos = ScopePos; 1502 addLocalScopeForVarDecl(VD); 1503 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1504 } 1505 1506 // The block we were processing is now finished. Make it the successor 1507 // block. 1508 if (Block) { 1509 Succ = Block; 1510 if (badCFG) 1511 return 0; 1512 } 1513 1514 // Process the false branch. 1515 CFGBlock *ElseBlock = Succ; 1516 1517 if (Stmt *Else = I->getElse()) { 1518 SaveAndRestore<CFGBlock*> sv(Succ); 1519 1520 // NULL out Block so that the recursive call to Visit will 1521 // create a new basic block. 1522 Block = NULL; 1523 1524 // If branch is not a compound statement create implicit scope 1525 // and add destructors. 1526 if (!isa<CompoundStmt>(Else)) 1527 addLocalScopeAndDtors(Else); 1528 1529 ElseBlock = addStmt(Else); 1530 1531 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1532 ElseBlock = sv.get(); 1533 else if (Block) { 1534 if (badCFG) 1535 return 0; 1536 } 1537 } 1538 1539 // Process the true branch. 1540 CFGBlock *ThenBlock; 1541 { 1542 Stmt *Then = I->getThen(); 1543 assert(Then); 1544 SaveAndRestore<CFGBlock*> sv(Succ); 1545 Block = NULL; 1546 1547 // If branch is not a compound statement create implicit scope 1548 // and add destructors. 1549 if (!isa<CompoundStmt>(Then)) 1550 addLocalScopeAndDtors(Then); 1551 1552 ThenBlock = addStmt(Then); 1553 1554 if (!ThenBlock) { 1555 // We can reach here if the "then" body has all NullStmts. 1556 // Create an empty block so we can distinguish between true and false 1557 // branches in path-sensitive analyses. 1558 ThenBlock = createBlock(false); 1559 addSuccessor(ThenBlock, sv.get()); 1560 } else if (Block) { 1561 if (badCFG) 1562 return 0; 1563 } 1564 } 1565 1566 // Now create a new block containing the if statement. 1567 Block = createBlock(false); 1568 1569 // Set the terminator of the new block to the If statement. 1570 Block->setTerminator(I); 1571 1572 // See if this is a known constant. 1573 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1574 1575 // Now add the successors. 1576 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1577 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1578 1579 // Add the condition as the last statement in the new block. This may create 1580 // new blocks as the condition may contain control-flow. Any newly created 1581 // blocks will be pointed to be "Block". 1582 Block = addStmt(I->getCond()); 1583 1584 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1585 // and the condition variable initialization to the CFG. 1586 if (VarDecl *VD = I->getConditionVariable()) { 1587 if (Expr *Init = VD->getInit()) { 1588 autoCreateBlock(); 1589 appendStmt(Block, I->getConditionVariableDeclStmt()); 1590 addStmt(Init); 1591 } 1592 } 1593 1594 return Block; 1595} 1596 1597 1598CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1599 // If we were in the middle of a block we stop processing that block. 1600 // 1601 // NOTE: If a "return" appears in the middle of a block, this means that the 1602 // code afterwards is DEAD (unreachable). We still keep a basic block 1603 // for that code; a simple "mark-and-sweep" from the entry block will be 1604 // able to report such dead blocks. 1605 1606 // Create the new block. 1607 Block = createBlock(false); 1608 1609 // The Exit block is the only successor. 1610 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1611 addSuccessor(Block, &cfg->getExit()); 1612 1613 // Add the return statement to the block. This may create new blocks if R 1614 // contains control-flow (short-circuit operations). 1615 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1616} 1617 1618CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1619 // Get the block of the labeled statement. Add it to our map. 1620 addStmt(L->getSubStmt()); 1621 CFGBlock *LabelBlock = Block; 1622 1623 if (!LabelBlock) // This can happen when the body is empty, i.e. 1624 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1625 1626 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1627 "label already in map"); 1628 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1629 1630 // Labels partition blocks, so this is the end of the basic block we were 1631 // processing (L is the block's label). Because this is label (and we have 1632 // already processed the substatement) there is no extra control-flow to worry 1633 // about. 1634 LabelBlock->setLabel(L); 1635 if (badCFG) 1636 return 0; 1637 1638 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1639 Block = NULL; 1640 1641 // This block is now the implicit successor of other blocks. 1642 Succ = LabelBlock; 1643 1644 return LabelBlock; 1645} 1646 1647CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1648 // Goto is a control-flow statement. Thus we stop processing the current 1649 // block and create a new one. 1650 1651 Block = createBlock(false); 1652 Block->setTerminator(G); 1653 1654 // If we already know the mapping to the label block add the successor now. 1655 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1656 1657 if (I == LabelMap.end()) 1658 // We will need to backpatch this block later. 1659 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1660 else { 1661 JumpTarget JT = I->second; 1662 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1663 addSuccessor(Block, JT.block); 1664 } 1665 1666 return Block; 1667} 1668 1669CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1670 CFGBlock *LoopSuccessor = NULL; 1671 1672 // Save local scope position because in case of condition variable ScopePos 1673 // won't be restored when traversing AST. 1674 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1675 1676 // Create local scope for init statement and possible condition variable. 1677 // Add destructor for init statement and condition variable. 1678 // Store scope position for continue statement. 1679 if (Stmt *Init = F->getInit()) 1680 addLocalScopeForStmt(Init); 1681 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1682 1683 if (VarDecl *VD = F->getConditionVariable()) 1684 addLocalScopeForVarDecl(VD); 1685 LocalScope::const_iterator ContinueScopePos = ScopePos; 1686 1687 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1688 1689 // "for" is a control-flow statement. Thus we stop processing the current 1690 // block. 1691 if (Block) { 1692 if (badCFG) 1693 return 0; 1694 LoopSuccessor = Block; 1695 } else 1696 LoopSuccessor = Succ; 1697 1698 // Save the current value for the break targets. 1699 // All breaks should go to the code following the loop. 1700 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1701 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1702 1703 // Because of short-circuit evaluation, the condition of the loop can span 1704 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1705 // evaluate the condition. 1706 CFGBlock *ExitConditionBlock = createBlock(false); 1707 CFGBlock *EntryConditionBlock = ExitConditionBlock; 1708 1709 // Set the terminator for the "exit" condition block. 1710 ExitConditionBlock->setTerminator(F); 1711 1712 // Now add the actual condition to the condition block. Because the condition 1713 // itself may contain control-flow, new blocks may be created. 1714 if (Stmt *C = F->getCond()) { 1715 Block = ExitConditionBlock; 1716 EntryConditionBlock = addStmt(C); 1717 if (badCFG) 1718 return 0; 1719 assert(Block == EntryConditionBlock || 1720 (Block == 0 && EntryConditionBlock == Succ)); 1721 1722 // If this block contains a condition variable, add both the condition 1723 // variable and initializer to the CFG. 1724 if (VarDecl *VD = F->getConditionVariable()) { 1725 if (Expr *Init = VD->getInit()) { 1726 autoCreateBlock(); 1727 appendStmt(Block, F->getConditionVariableDeclStmt()); 1728 EntryConditionBlock = addStmt(Init); 1729 assert(Block == EntryConditionBlock); 1730 } 1731 } 1732 1733 if (Block) { 1734 if (badCFG) 1735 return 0; 1736 } 1737 } 1738 1739 // The condition block is the implicit successor for the loop body as well as 1740 // any code above the loop. 1741 Succ = EntryConditionBlock; 1742 1743 // See if this is a known constant. 1744 TryResult KnownVal(true); 1745 1746 if (F->getCond()) 1747 KnownVal = tryEvaluateBool(F->getCond()); 1748 1749 // Now create the loop body. 1750 { 1751 assert(F->getBody()); 1752 1753 // Save the current values for Block, Succ, and continue targets. 1754 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1755 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1756 1757 // Create a new block to contain the (bottom) of the loop body. 1758 Block = NULL; 1759 1760 // Loop body should end with destructor of Condition variable (if any). 1761 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1762 1763 if (Stmt *I = F->getInc()) { 1764 // Generate increment code in its own basic block. This is the target of 1765 // continue statements. 1766 Succ = addStmt(I); 1767 } else { 1768 // No increment code. Create a special, empty, block that is used as the 1769 // target block for "looping back" to the start of the loop. 1770 assert(Succ == EntryConditionBlock); 1771 Succ = Block ? Block : createBlock(); 1772 } 1773 1774 // Finish up the increment (or empty) block if it hasn't been already. 1775 if (Block) { 1776 assert(Block == Succ); 1777 if (badCFG) 1778 return 0; 1779 Block = 0; 1780 } 1781 1782 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1783 1784 // The starting block for the loop increment is the block that should 1785 // represent the 'loop target' for looping back to the start of the loop. 1786 ContinueJumpTarget.block->setLoopTarget(F); 1787 1788 // If body is not a compound statement create implicit scope 1789 // and add destructors. 1790 if (!isa<CompoundStmt>(F->getBody())) 1791 addLocalScopeAndDtors(F->getBody()); 1792 1793 // Now populate the body block, and in the process create new blocks as we 1794 // walk the body of the loop. 1795 CFGBlock *BodyBlock = addStmt(F->getBody()); 1796 1797 if (!BodyBlock) 1798 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1799 else if (badCFG) 1800 return 0; 1801 1802 // This new body block is a successor to our "exit" condition block. 1803 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1804 } 1805 1806 // Link up the condition block with the code that follows the loop. (the 1807 // false branch). 1808 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1809 1810 // If the loop contains initialization, create a new block for those 1811 // statements. This block can also contain statements that precede the loop. 1812 if (Stmt *I = F->getInit()) { 1813 Block = createBlock(); 1814 return addStmt(I); 1815 } 1816 1817 // There is no loop initialization. We are thus basically a while loop. 1818 // NULL out Block to force lazy block construction. 1819 Block = NULL; 1820 Succ = EntryConditionBlock; 1821 return EntryConditionBlock; 1822} 1823 1824CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1825 if (asc.alwaysAdd(*this, M)) { 1826 autoCreateBlock(); 1827 appendStmt(Block, M); 1828 } 1829 return Visit(M->getBase()); 1830} 1831 1832CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 1833 // Objective-C fast enumeration 'for' statements: 1834 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1835 // 1836 // for ( Type newVariable in collection_expression ) { statements } 1837 // 1838 // becomes: 1839 // 1840 // prologue: 1841 // 1. collection_expression 1842 // T. jump to loop_entry 1843 // loop_entry: 1844 // 1. side-effects of element expression 1845 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1846 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1847 // TB: 1848 // statements 1849 // T. jump to loop_entry 1850 // FB: 1851 // what comes after 1852 // 1853 // and 1854 // 1855 // Type existingItem; 1856 // for ( existingItem in expression ) { statements } 1857 // 1858 // becomes: 1859 // 1860 // the same with newVariable replaced with existingItem; the binding works 1861 // the same except that for one ObjCForCollectionStmt::getElement() returns 1862 // a DeclStmt and the other returns a DeclRefExpr. 1863 // 1864 1865 CFGBlock *LoopSuccessor = 0; 1866 1867 if (Block) { 1868 if (badCFG) 1869 return 0; 1870 LoopSuccessor = Block; 1871 Block = 0; 1872 } else 1873 LoopSuccessor = Succ; 1874 1875 // Build the condition blocks. 1876 CFGBlock *ExitConditionBlock = createBlock(false); 1877 1878 // Set the terminator for the "exit" condition block. 1879 ExitConditionBlock->setTerminator(S); 1880 1881 // The last statement in the block should be the ObjCForCollectionStmt, which 1882 // performs the actual binding to 'element' and determines if there are any 1883 // more items in the collection. 1884 appendStmt(ExitConditionBlock, S); 1885 Block = ExitConditionBlock; 1886 1887 // Walk the 'element' expression to see if there are any side-effects. We 1888 // generate new blocks as necessary. We DON'T add the statement by default to 1889 // the CFG unless it contains control-flow. 1890 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 1891 AddStmtChoice::NotAlwaysAdd); 1892 if (Block) { 1893 if (badCFG) 1894 return 0; 1895 Block = 0; 1896 } 1897 1898 // The condition block is the implicit successor for the loop body as well as 1899 // any code above the loop. 1900 Succ = EntryConditionBlock; 1901 1902 // Now create the true branch. 1903 { 1904 // Save the current values for Succ, continue and break targets. 1905 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1906 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1907 save_break(BreakJumpTarget); 1908 1909 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1910 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1911 1912 CFGBlock *BodyBlock = addStmt(S->getBody()); 1913 1914 if (!BodyBlock) 1915 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1916 else if (Block) { 1917 if (badCFG) 1918 return 0; 1919 } 1920 1921 // This new body block is a successor to our "exit" condition block. 1922 addSuccessor(ExitConditionBlock, BodyBlock); 1923 } 1924 1925 // Link up the condition block with the code that follows the loop. 1926 // (the false branch). 1927 addSuccessor(ExitConditionBlock, LoopSuccessor); 1928 1929 // Now create a prologue block to contain the collection expression. 1930 Block = createBlock(); 1931 return addStmt(S->getCollection()); 1932} 1933 1934CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 1935 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1936 1937 // Inline the body. 1938 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1939 1940 // The sync body starts its own basic block. This makes it a little easier 1941 // for diagnostic clients. 1942 if (SyncBlock) { 1943 if (badCFG) 1944 return 0; 1945 1946 Block = 0; 1947 Succ = SyncBlock; 1948 } 1949 1950 // Add the @synchronized to the CFG. 1951 autoCreateBlock(); 1952 appendStmt(Block, S); 1953 1954 // Inline the sync expression. 1955 return addStmt(S->getSynchExpr()); 1956} 1957 1958CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 1959 // FIXME 1960 return NYS(); 1961} 1962 1963CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) { 1964 autoCreateBlock(); 1965 1966 // Add the PseudoObject as the last thing. 1967 appendStmt(Block, E); 1968 1969 CFGBlock *lastBlock = Block; 1970 1971 // Before that, evaluate all of the semantics in order. In 1972 // CFG-land, that means appending them in reverse order. 1973 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) { 1974 Expr *Semantic = E->getSemanticExpr(--i); 1975 1976 // If the semantic is an opaque value, we're being asked to bind 1977 // it to its source expression. 1978 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic)) 1979 Semantic = OVE->getSourceExpr(); 1980 1981 if (CFGBlock *B = Visit(Semantic)) 1982 lastBlock = B; 1983 } 1984 1985 return lastBlock; 1986} 1987 1988CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 1989 CFGBlock *LoopSuccessor = NULL; 1990 1991 // Save local scope position because in case of condition variable ScopePos 1992 // won't be restored when traversing AST. 1993 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1994 1995 // Create local scope for possible condition variable. 1996 // Store scope position for continue statement. 1997 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1998 if (VarDecl *VD = W->getConditionVariable()) { 1999 addLocalScopeForVarDecl(VD); 2000 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2001 } 2002 2003 // "while" is a control-flow statement. Thus we stop processing the current 2004 // block. 2005 if (Block) { 2006 if (badCFG) 2007 return 0; 2008 LoopSuccessor = Block; 2009 Block = 0; 2010 } else 2011 LoopSuccessor = Succ; 2012 2013 // Because of short-circuit evaluation, the condition of the loop can span 2014 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2015 // evaluate the condition. 2016 CFGBlock *ExitConditionBlock = createBlock(false); 2017 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2018 2019 // Set the terminator for the "exit" condition block. 2020 ExitConditionBlock->setTerminator(W); 2021 2022 // Now add the actual condition to the condition block. Because the condition 2023 // itself may contain control-flow, new blocks may be created. Thus we update 2024 // "Succ" after adding the condition. 2025 if (Stmt *C = W->getCond()) { 2026 Block = ExitConditionBlock; 2027 EntryConditionBlock = addStmt(C); 2028 // The condition might finish the current 'Block'. 2029 Block = EntryConditionBlock; 2030 2031 // If this block contains a condition variable, add both the condition 2032 // variable and initializer to the CFG. 2033 if (VarDecl *VD = W->getConditionVariable()) { 2034 if (Expr *Init = VD->getInit()) { 2035 autoCreateBlock(); 2036 appendStmt(Block, W->getConditionVariableDeclStmt()); 2037 EntryConditionBlock = addStmt(Init); 2038 assert(Block == EntryConditionBlock); 2039 } 2040 } 2041 2042 if (Block) { 2043 if (badCFG) 2044 return 0; 2045 } 2046 } 2047 2048 // The condition block is the implicit successor for the loop body as well as 2049 // any code above the loop. 2050 Succ = EntryConditionBlock; 2051 2052 // See if this is a known constant. 2053 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 2054 2055 // Process the loop body. 2056 { 2057 assert(W->getBody()); 2058 2059 // Save the current values for Block, Succ, and continue and break targets 2060 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2061 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2062 save_break(BreakJumpTarget); 2063 2064 // Create an empty block to represent the transition block for looping back 2065 // to the head of the loop. 2066 Block = 0; 2067 assert(Succ == EntryConditionBlock); 2068 Succ = createBlock(); 2069 Succ->setLoopTarget(W); 2070 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 2071 2072 // All breaks should go to the code following the loop. 2073 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2074 2075 // NULL out Block to force lazy instantiation of blocks for the body. 2076 Block = NULL; 2077 2078 // Loop body should end with destructor of Condition variable (if any). 2079 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2080 2081 // If body is not a compound statement create implicit scope 2082 // and add destructors. 2083 if (!isa<CompoundStmt>(W->getBody())) 2084 addLocalScopeAndDtors(W->getBody()); 2085 2086 // Create the body. The returned block is the entry to the loop body. 2087 CFGBlock *BodyBlock = addStmt(W->getBody()); 2088 2089 if (!BodyBlock) 2090 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2091 else if (Block) { 2092 if (badCFG) 2093 return 0; 2094 } 2095 2096 // Add the loop body entry as a successor to the condition. 2097 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2098 } 2099 2100 // Link up the condition block with the code that follows the loop. (the 2101 // false branch). 2102 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2103 2104 // There can be no more statements in the condition block since we loop back 2105 // to this block. NULL out Block to force lazy creation of another block. 2106 Block = NULL; 2107 2108 // Return the condition block, which is the dominating block for the loop. 2109 Succ = EntryConditionBlock; 2110 return EntryConditionBlock; 2111} 2112 2113 2114CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2115 // FIXME: For now we pretend that @catch and the code it contains does not 2116 // exit. 2117 return Block; 2118} 2119 2120CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2121 // FIXME: This isn't complete. We basically treat @throw like a return 2122 // statement. 2123 2124 // If we were in the middle of a block we stop processing that block. 2125 if (badCFG) 2126 return 0; 2127 2128 // Create the new block. 2129 Block = createBlock(false); 2130 2131 // The Exit block is the only successor. 2132 addSuccessor(Block, &cfg->getExit()); 2133 2134 // Add the statement to the block. This may create new blocks if S contains 2135 // control-flow (short-circuit operations). 2136 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2137} 2138 2139CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2140 // If we were in the middle of a block we stop processing that block. 2141 if (badCFG) 2142 return 0; 2143 2144 // Create the new block. 2145 Block = createBlock(false); 2146 2147 if (TryTerminatedBlock) 2148 // The current try statement is the only successor. 2149 addSuccessor(Block, TryTerminatedBlock); 2150 else 2151 // otherwise the Exit block is the only successor. 2152 addSuccessor(Block, &cfg->getExit()); 2153 2154 // Add the statement to the block. This may create new blocks if S contains 2155 // control-flow (short-circuit operations). 2156 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2157} 2158 2159CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2160 CFGBlock *LoopSuccessor = NULL; 2161 2162 // "do...while" is a control-flow statement. Thus we stop processing the 2163 // current block. 2164 if (Block) { 2165 if (badCFG) 2166 return 0; 2167 LoopSuccessor = Block; 2168 } else 2169 LoopSuccessor = Succ; 2170 2171 // Because of short-circuit evaluation, the condition of the loop can span 2172 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2173 // evaluate the condition. 2174 CFGBlock *ExitConditionBlock = createBlock(false); 2175 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2176 2177 // Set the terminator for the "exit" condition block. 2178 ExitConditionBlock->setTerminator(D); 2179 2180 // Now add the actual condition to the condition block. Because the condition 2181 // itself may contain control-flow, new blocks may be created. 2182 if (Stmt *C = D->getCond()) { 2183 Block = ExitConditionBlock; 2184 EntryConditionBlock = addStmt(C); 2185 if (Block) { 2186 if (badCFG) 2187 return 0; 2188 } 2189 } 2190 2191 // The condition block is the implicit successor for the loop body. 2192 Succ = EntryConditionBlock; 2193 2194 // See if this is a known constant. 2195 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2196 2197 // Process the loop body. 2198 CFGBlock *BodyBlock = NULL; 2199 { 2200 assert(D->getBody()); 2201 2202 // Save the current values for Block, Succ, and continue and break targets 2203 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2204 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2205 save_break(BreakJumpTarget); 2206 2207 // All continues within this loop should go to the condition block 2208 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2209 2210 // All breaks should go to the code following the loop. 2211 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2212 2213 // NULL out Block to force lazy instantiation of blocks for the body. 2214 Block = NULL; 2215 2216 // If body is not a compound statement create implicit scope 2217 // and add destructors. 2218 if (!isa<CompoundStmt>(D->getBody())) 2219 addLocalScopeAndDtors(D->getBody()); 2220 2221 // Create the body. The returned block is the entry to the loop body. 2222 BodyBlock = addStmt(D->getBody()); 2223 2224 if (!BodyBlock) 2225 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2226 else if (Block) { 2227 if (badCFG) 2228 return 0; 2229 } 2230 2231 if (!KnownVal.isFalse()) { 2232 // Add an intermediate block between the BodyBlock and the 2233 // ExitConditionBlock to represent the "loop back" transition. Create an 2234 // empty block to represent the transition block for looping back to the 2235 // head of the loop. 2236 // FIXME: Can we do this more efficiently without adding another block? 2237 Block = NULL; 2238 Succ = BodyBlock; 2239 CFGBlock *LoopBackBlock = createBlock(); 2240 LoopBackBlock->setLoopTarget(D); 2241 2242 // Add the loop body entry as a successor to the condition. 2243 addSuccessor(ExitConditionBlock, LoopBackBlock); 2244 } 2245 else 2246 addSuccessor(ExitConditionBlock, NULL); 2247 } 2248 2249 // Link up the condition block with the code that follows the loop. 2250 // (the false branch). 2251 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2252 2253 // There can be no more statements in the body block(s) since we loop back to 2254 // the body. NULL out Block to force lazy creation of another block. 2255 Block = NULL; 2256 2257 // Return the loop body, which is the dominating block for the loop. 2258 Succ = BodyBlock; 2259 return BodyBlock; 2260} 2261 2262CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2263 // "continue" is a control-flow statement. Thus we stop processing the 2264 // current block. 2265 if (badCFG) 2266 return 0; 2267 2268 // Now create a new block that ends with the continue statement. 2269 Block = createBlock(false); 2270 Block->setTerminator(C); 2271 2272 // If there is no target for the continue, then we are looking at an 2273 // incomplete AST. This means the CFG cannot be constructed. 2274 if (ContinueJumpTarget.block) { 2275 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2276 addSuccessor(Block, ContinueJumpTarget.block); 2277 } else 2278 badCFG = true; 2279 2280 return Block; 2281} 2282 2283CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2284 AddStmtChoice asc) { 2285 2286 if (asc.alwaysAdd(*this, E)) { 2287 autoCreateBlock(); 2288 appendStmt(Block, E); 2289 } 2290 2291 // VLA types have expressions that must be evaluated. 2292 CFGBlock *lastBlock = Block; 2293 2294 if (E->isArgumentType()) { 2295 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2296 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2297 lastBlock = addStmt(VA->getSizeExpr()); 2298 } 2299 return lastBlock; 2300} 2301 2302/// VisitStmtExpr - Utility method to handle (nested) statement 2303/// expressions (a GCC extension). 2304CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2305 if (asc.alwaysAdd(*this, SE)) { 2306 autoCreateBlock(); 2307 appendStmt(Block, SE); 2308 } 2309 return VisitCompoundStmt(SE->getSubStmt()); 2310} 2311 2312CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2313 // "switch" is a control-flow statement. Thus we stop processing the current 2314 // block. 2315 CFGBlock *SwitchSuccessor = NULL; 2316 2317 // Save local scope position because in case of condition variable ScopePos 2318 // won't be restored when traversing AST. 2319 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2320 2321 // Create local scope for possible condition variable. 2322 // Store scope position. Add implicit destructor. 2323 if (VarDecl *VD = Terminator->getConditionVariable()) { 2324 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2325 addLocalScopeForVarDecl(VD); 2326 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2327 } 2328 2329 if (Block) { 2330 if (badCFG) 2331 return 0; 2332 SwitchSuccessor = Block; 2333 } else SwitchSuccessor = Succ; 2334 2335 // Save the current "switch" context. 2336 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2337 save_default(DefaultCaseBlock); 2338 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2339 2340 // Set the "default" case to be the block after the switch statement. If the 2341 // switch statement contains a "default:", this value will be overwritten with 2342 // the block for that code. 2343 DefaultCaseBlock = SwitchSuccessor; 2344 2345 // Create a new block that will contain the switch statement. 2346 SwitchTerminatedBlock = createBlock(false); 2347 2348 // Now process the switch body. The code after the switch is the implicit 2349 // successor. 2350 Succ = SwitchSuccessor; 2351 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2352 2353 // When visiting the body, the case statements should automatically get linked 2354 // up to the switch. We also don't keep a pointer to the body, since all 2355 // control-flow from the switch goes to case/default statements. 2356 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2357 Block = NULL; 2358 2359 // For pruning unreachable case statements, save the current state 2360 // for tracking the condition value. 2361 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2362 false); 2363 2364 // Determine if the switch condition can be explicitly evaluated. 2365 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2366 Expr::EvalResult result; 2367 bool b = tryEvaluate(Terminator->getCond(), result); 2368 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2369 b ? &result : 0); 2370 2371 // If body is not a compound statement create implicit scope 2372 // and add destructors. 2373 if (!isa<CompoundStmt>(Terminator->getBody())) 2374 addLocalScopeAndDtors(Terminator->getBody()); 2375 2376 addStmt(Terminator->getBody()); 2377 if (Block) { 2378 if (badCFG) 2379 return 0; 2380 } 2381 2382 // If we have no "default:" case, the default transition is to the code 2383 // following the switch body. Moreover, take into account if all the 2384 // cases of a switch are covered (e.g., switching on an enum value). 2385 addSuccessor(SwitchTerminatedBlock, 2386 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2387 ? 0 : DefaultCaseBlock); 2388 2389 // Add the terminator and condition in the switch block. 2390 SwitchTerminatedBlock->setTerminator(Terminator); 2391 Block = SwitchTerminatedBlock; 2392 Block = addStmt(Terminator->getCond()); 2393 2394 // Finally, if the SwitchStmt contains a condition variable, add both the 2395 // SwitchStmt and the condition variable initialization to the CFG. 2396 if (VarDecl *VD = Terminator->getConditionVariable()) { 2397 if (Expr *Init = VD->getInit()) { 2398 autoCreateBlock(); 2399 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2400 addStmt(Init); 2401 } 2402 } 2403 2404 return Block; 2405} 2406 2407static bool shouldAddCase(bool &switchExclusivelyCovered, 2408 const Expr::EvalResult *switchCond, 2409 const CaseStmt *CS, 2410 ASTContext &Ctx) { 2411 if (!switchCond) 2412 return true; 2413 2414 bool addCase = false; 2415 2416 if (!switchExclusivelyCovered) { 2417 if (switchCond->Val.isInt()) { 2418 // Evaluate the LHS of the case value. 2419 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2420 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2421 2422 if (condInt == lhsInt) { 2423 addCase = true; 2424 switchExclusivelyCovered = true; 2425 } 2426 else if (condInt < lhsInt) { 2427 if (const Expr *RHS = CS->getRHS()) { 2428 // Evaluate the RHS of the case value. 2429 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2430 if (V2 <= condInt) { 2431 addCase = true; 2432 switchExclusivelyCovered = true; 2433 } 2434 } 2435 } 2436 } 2437 else 2438 addCase = true; 2439 } 2440 return addCase; 2441} 2442 2443CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2444 // CaseStmts are essentially labels, so they are the first statement in a 2445 // block. 2446 CFGBlock *TopBlock = 0, *LastBlock = 0; 2447 2448 if (Stmt *Sub = CS->getSubStmt()) { 2449 // For deeply nested chains of CaseStmts, instead of doing a recursion 2450 // (which can blow out the stack), manually unroll and create blocks 2451 // along the way. 2452 while (isa<CaseStmt>(Sub)) { 2453 CFGBlock *currentBlock = createBlock(false); 2454 currentBlock->setLabel(CS); 2455 2456 if (TopBlock) 2457 addSuccessor(LastBlock, currentBlock); 2458 else 2459 TopBlock = currentBlock; 2460 2461 addSuccessor(SwitchTerminatedBlock, 2462 shouldAddCase(switchExclusivelyCovered, switchCond, 2463 CS, *Context) 2464 ? currentBlock : 0); 2465 2466 LastBlock = currentBlock; 2467 CS = cast<CaseStmt>(Sub); 2468 Sub = CS->getSubStmt(); 2469 } 2470 2471 addStmt(Sub); 2472 } 2473 2474 CFGBlock *CaseBlock = Block; 2475 if (!CaseBlock) 2476 CaseBlock = createBlock(); 2477 2478 // Cases statements partition blocks, so this is the top of the basic block we 2479 // were processing (the "case XXX:" is the label). 2480 CaseBlock->setLabel(CS); 2481 2482 if (badCFG) 2483 return 0; 2484 2485 // Add this block to the list of successors for the block with the switch 2486 // statement. 2487 assert(SwitchTerminatedBlock); 2488 addSuccessor(SwitchTerminatedBlock, 2489 shouldAddCase(switchExclusivelyCovered, switchCond, 2490 CS, *Context) 2491 ? CaseBlock : 0); 2492 2493 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2494 Block = NULL; 2495 2496 if (TopBlock) { 2497 addSuccessor(LastBlock, CaseBlock); 2498 Succ = TopBlock; 2499 } else { 2500 // This block is now the implicit successor of other blocks. 2501 Succ = CaseBlock; 2502 } 2503 2504 return Succ; 2505} 2506 2507CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2508 if (Terminator->getSubStmt()) 2509 addStmt(Terminator->getSubStmt()); 2510 2511 DefaultCaseBlock = Block; 2512 2513 if (!DefaultCaseBlock) 2514 DefaultCaseBlock = createBlock(); 2515 2516 // Default statements partition blocks, so this is the top of the basic block 2517 // we were processing (the "default:" is the label). 2518 DefaultCaseBlock->setLabel(Terminator); 2519 2520 if (badCFG) 2521 return 0; 2522 2523 // Unlike case statements, we don't add the default block to the successors 2524 // for the switch statement immediately. This is done when we finish 2525 // processing the switch statement. This allows for the default case 2526 // (including a fall-through to the code after the switch statement) to always 2527 // be the last successor of a switch-terminated block. 2528 2529 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2530 Block = NULL; 2531 2532 // This block is now the implicit successor of other blocks. 2533 Succ = DefaultCaseBlock; 2534 2535 return DefaultCaseBlock; 2536} 2537 2538CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2539 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2540 // current block. 2541 CFGBlock *TrySuccessor = NULL; 2542 2543 if (Block) { 2544 if (badCFG) 2545 return 0; 2546 TrySuccessor = Block; 2547 } else TrySuccessor = Succ; 2548 2549 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2550 2551 // Create a new block that will contain the try statement. 2552 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2553 // Add the terminator in the try block. 2554 NewTryTerminatedBlock->setTerminator(Terminator); 2555 2556 bool HasCatchAll = false; 2557 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2558 // The code after the try is the implicit successor. 2559 Succ = TrySuccessor; 2560 CXXCatchStmt *CS = Terminator->getHandler(h); 2561 if (CS->getExceptionDecl() == 0) { 2562 HasCatchAll = true; 2563 } 2564 Block = NULL; 2565 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2566 if (CatchBlock == 0) 2567 return 0; 2568 // Add this block to the list of successors for the block with the try 2569 // statement. 2570 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2571 } 2572 if (!HasCatchAll) { 2573 if (PrevTryTerminatedBlock) 2574 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2575 else 2576 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2577 } 2578 2579 // The code after the try is the implicit successor. 2580 Succ = TrySuccessor; 2581 2582 // Save the current "try" context. 2583 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2584 cfg->addTryDispatchBlock(TryTerminatedBlock); 2585 2586 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2587 Block = NULL; 2588 Block = addStmt(Terminator->getTryBlock()); 2589 return Block; 2590} 2591 2592CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2593 // CXXCatchStmt are treated like labels, so they are the first statement in a 2594 // block. 2595 2596 // Save local scope position because in case of exception variable ScopePos 2597 // won't be restored when traversing AST. 2598 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2599 2600 // Create local scope for possible exception variable. 2601 // Store scope position. Add implicit destructor. 2602 if (VarDecl *VD = CS->getExceptionDecl()) { 2603 LocalScope::const_iterator BeginScopePos = ScopePos; 2604 addLocalScopeForVarDecl(VD); 2605 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2606 } 2607 2608 if (CS->getHandlerBlock()) 2609 addStmt(CS->getHandlerBlock()); 2610 2611 CFGBlock *CatchBlock = Block; 2612 if (!CatchBlock) 2613 CatchBlock = createBlock(); 2614 2615 CatchBlock->setLabel(CS); 2616 2617 if (badCFG) 2618 return 0; 2619 2620 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2621 Block = NULL; 2622 2623 return CatchBlock; 2624} 2625 2626CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2627 // C++0x for-range statements are specified as [stmt.ranged]: 2628 // 2629 // { 2630 // auto && __range = range-init; 2631 // for ( auto __begin = begin-expr, 2632 // __end = end-expr; 2633 // __begin != __end; 2634 // ++__begin ) { 2635 // for-range-declaration = *__begin; 2636 // statement 2637 // } 2638 // } 2639 2640 // Save local scope position before the addition of the implicit variables. 2641 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2642 2643 // Create local scopes and destructors for range, begin and end variables. 2644 if (Stmt *Range = S->getRangeStmt()) 2645 addLocalScopeForStmt(Range); 2646 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2647 addLocalScopeForStmt(BeginEnd); 2648 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2649 2650 LocalScope::const_iterator ContinueScopePos = ScopePos; 2651 2652 // "for" is a control-flow statement. Thus we stop processing the current 2653 // block. 2654 CFGBlock *LoopSuccessor = NULL; 2655 if (Block) { 2656 if (badCFG) 2657 return 0; 2658 LoopSuccessor = Block; 2659 } else 2660 LoopSuccessor = Succ; 2661 2662 // Save the current value for the break targets. 2663 // All breaks should go to the code following the loop. 2664 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2665 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2666 2667 // The block for the __begin != __end expression. 2668 CFGBlock *ConditionBlock = createBlock(false); 2669 ConditionBlock->setTerminator(S); 2670 2671 // Now add the actual condition to the condition block. 2672 if (Expr *C = S->getCond()) { 2673 Block = ConditionBlock; 2674 CFGBlock *BeginConditionBlock = addStmt(C); 2675 if (badCFG) 2676 return 0; 2677 assert(BeginConditionBlock == ConditionBlock && 2678 "condition block in for-range was unexpectedly complex"); 2679 (void)BeginConditionBlock; 2680 } 2681 2682 // The condition block is the implicit successor for the loop body as well as 2683 // any code above the loop. 2684 Succ = ConditionBlock; 2685 2686 // See if this is a known constant. 2687 TryResult KnownVal(true); 2688 2689 if (S->getCond()) 2690 KnownVal = tryEvaluateBool(S->getCond()); 2691 2692 // Now create the loop body. 2693 { 2694 assert(S->getBody()); 2695 2696 // Save the current values for Block, Succ, and continue targets. 2697 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2698 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2699 2700 // Generate increment code in its own basic block. This is the target of 2701 // continue statements. 2702 Block = 0; 2703 Succ = addStmt(S->getInc()); 2704 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2705 2706 // The starting block for the loop increment is the block that should 2707 // represent the 'loop target' for looping back to the start of the loop. 2708 ContinueJumpTarget.block->setLoopTarget(S); 2709 2710 // Finish up the increment block and prepare to start the loop body. 2711 assert(Block); 2712 if (badCFG) 2713 return 0; 2714 Block = 0; 2715 2716 2717 // Add implicit scope and dtors for loop variable. 2718 addLocalScopeAndDtors(S->getLoopVarStmt()); 2719 2720 // Populate a new block to contain the loop body and loop variable. 2721 Block = addStmt(S->getBody()); 2722 if (badCFG) 2723 return 0; 2724 Block = addStmt(S->getLoopVarStmt()); 2725 if (badCFG) 2726 return 0; 2727 2728 // This new body block is a successor to our condition block. 2729 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2730 } 2731 2732 // Link up the condition block with the code that follows the loop (the 2733 // false branch). 2734 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2735 2736 // Add the initialization statements. 2737 Block = createBlock(); 2738 addStmt(S->getBeginEndStmt()); 2739 return addStmt(S->getRangeStmt()); 2740} 2741 2742CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2743 AddStmtChoice asc) { 2744 if (BuildOpts.AddImplicitDtors) { 2745 // If adding implicit destructors visit the full expression for adding 2746 // destructors of temporaries. 2747 VisitForTemporaryDtors(E->getSubExpr()); 2748 2749 // Full expression has to be added as CFGStmt so it will be sequenced 2750 // before destructors of it's temporaries. 2751 asc = asc.withAlwaysAdd(true); 2752 } 2753 return Visit(E->getSubExpr(), asc); 2754} 2755 2756CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2757 AddStmtChoice asc) { 2758 if (asc.alwaysAdd(*this, E)) { 2759 autoCreateBlock(); 2760 appendStmt(Block, E); 2761 2762 // We do not want to propagate the AlwaysAdd property. 2763 asc = asc.withAlwaysAdd(false); 2764 } 2765 return Visit(E->getSubExpr(), asc); 2766} 2767 2768CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2769 AddStmtChoice asc) { 2770 autoCreateBlock(); 2771 if (!C->isElidable() && asc.alwaysAdd(*this, C)) 2772 appendStmt(Block, C); 2773 2774 return VisitChildren(C); 2775} 2776 2777CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2778 AddStmtChoice asc) { 2779 if (asc.alwaysAdd(*this, E)) { 2780 autoCreateBlock(); 2781 appendStmt(Block, E); 2782 // We do not want to propagate the AlwaysAdd property. 2783 asc = asc.withAlwaysAdd(false); 2784 } 2785 return Visit(E->getSubExpr(), asc); 2786} 2787 2788CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2789 AddStmtChoice asc) { 2790 autoCreateBlock(); 2791 appendStmt(Block, C); 2792 return VisitChildren(C); 2793} 2794 2795CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2796 AddStmtChoice asc) { 2797 if (asc.alwaysAdd(*this, E)) { 2798 autoCreateBlock(); 2799 appendStmt(Block, E); 2800 } 2801 return Visit(E->getSubExpr(), AddStmtChoice()); 2802} 2803 2804CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 2805 // Lazily create the indirect-goto dispatch block if there isn't one already. 2806 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 2807 2808 if (!IBlock) { 2809 IBlock = createBlock(false); 2810 cfg->setIndirectGotoBlock(IBlock); 2811 } 2812 2813 // IndirectGoto is a control-flow statement. Thus we stop processing the 2814 // current block and create a new one. 2815 if (badCFG) 2816 return 0; 2817 2818 Block = createBlock(false); 2819 Block->setTerminator(I); 2820 addSuccessor(Block, IBlock); 2821 return addStmt(I->getTarget()); 2822} 2823 2824CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2825tryAgain: 2826 if (!E) { 2827 badCFG = true; 2828 return NULL; 2829 } 2830 switch (E->getStmtClass()) { 2831 default: 2832 return VisitChildrenForTemporaryDtors(E); 2833 2834 case Stmt::BinaryOperatorClass: 2835 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2836 2837 case Stmt::CXXBindTemporaryExprClass: 2838 return VisitCXXBindTemporaryExprForTemporaryDtors( 2839 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2840 2841 case Stmt::BinaryConditionalOperatorClass: 2842 case Stmt::ConditionalOperatorClass: 2843 return VisitConditionalOperatorForTemporaryDtors( 2844 cast<AbstractConditionalOperator>(E), BindToTemporary); 2845 2846 case Stmt::ImplicitCastExprClass: 2847 // For implicit cast we want BindToTemporary to be passed further. 2848 E = cast<CastExpr>(E)->getSubExpr(); 2849 goto tryAgain; 2850 2851 case Stmt::ParenExprClass: 2852 E = cast<ParenExpr>(E)->getSubExpr(); 2853 goto tryAgain; 2854 2855 case Stmt::MaterializeTemporaryExprClass: 2856 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 2857 goto tryAgain; 2858 } 2859} 2860 2861CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2862 // When visiting children for destructors we want to visit them in reverse 2863 // order. Because there's no reverse iterator for children must to reverse 2864 // them in helper vector. 2865 typedef SmallVector<Stmt *, 4> ChildrenVect; 2866 ChildrenVect ChildrenRev; 2867 for (Stmt::child_range I = E->children(); I; ++I) { 2868 if (*I) ChildrenRev.push_back(*I); 2869 } 2870 2871 CFGBlock *B = Block; 2872 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2873 L = ChildrenRev.rend(); I != L; ++I) { 2874 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2875 B = R; 2876 } 2877 return B; 2878} 2879 2880CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2881 if (E->isLogicalOp()) { 2882 // Destructors for temporaries in LHS expression should be called after 2883 // those for RHS expression. Even if this will unnecessarily create a block, 2884 // this block will be used at least by the full expression. 2885 autoCreateBlock(); 2886 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2887 if (badCFG) 2888 return NULL; 2889 2890 Succ = ConfluenceBlock; 2891 Block = NULL; 2892 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2893 2894 if (RHSBlock) { 2895 if (badCFG) 2896 return NULL; 2897 2898 // If RHS expression did produce destructors we need to connect created 2899 // blocks to CFG in same manner as for binary operator itself. 2900 CFGBlock *LHSBlock = createBlock(false); 2901 LHSBlock->setTerminator(CFGTerminator(E, true)); 2902 2903 // For binary operator LHS block is before RHS in list of predecessors 2904 // of ConfluenceBlock. 2905 std::reverse(ConfluenceBlock->pred_begin(), 2906 ConfluenceBlock->pred_end()); 2907 2908 // See if this is a known constant. 2909 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2910 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2911 KnownVal.negate(); 2912 2913 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2914 // itself. 2915 if (E->getOpcode() == BO_LOr) { 2916 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2917 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2918 } else { 2919 assert (E->getOpcode() == BO_LAnd); 2920 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2921 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2922 } 2923 2924 Block = LHSBlock; 2925 return LHSBlock; 2926 } 2927 2928 Block = ConfluenceBlock; 2929 return ConfluenceBlock; 2930 } 2931 2932 if (E->isAssignmentOp()) { 2933 // For assignment operator (=) LHS expression is visited 2934 // before RHS expression. For destructors visit them in reverse order. 2935 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2936 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2937 return LHSBlock ? LHSBlock : RHSBlock; 2938 } 2939 2940 // For any other binary operator RHS expression is visited before 2941 // LHS expression (order of children). For destructors visit them in reverse 2942 // order. 2943 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2944 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2945 return RHSBlock ? RHSBlock : LHSBlock; 2946} 2947 2948CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2949 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2950 // First add destructors for temporaries in subexpression. 2951 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2952 if (!BindToTemporary) { 2953 // If lifetime of temporary is not prolonged (by assigning to constant 2954 // reference) add destructor for it. 2955 2956 // If the destructor is marked as a no-return destructor, we need to create 2957 // a new block for the destructor which does not have as a successor 2958 // anything built thus far. Control won't flow out of this block. 2959 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 2960 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 2961 Block = createNoReturnBlock(); 2962 else 2963 autoCreateBlock(); 2964 2965 appendTemporaryDtor(Block, E); 2966 B = Block; 2967 } 2968 return B; 2969} 2970 2971CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2972 AbstractConditionalOperator *E, bool BindToTemporary) { 2973 // First add destructors for condition expression. Even if this will 2974 // unnecessarily create a block, this block will be used at least by the full 2975 // expression. 2976 autoCreateBlock(); 2977 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2978 if (badCFG) 2979 return NULL; 2980 if (BinaryConditionalOperator *BCO 2981 = dyn_cast<BinaryConditionalOperator>(E)) { 2982 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2983 if (badCFG) 2984 return NULL; 2985 } 2986 2987 // Try to add block with destructors for LHS expression. 2988 CFGBlock *LHSBlock = NULL; 2989 Succ = ConfluenceBlock; 2990 Block = NULL; 2991 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2992 if (badCFG) 2993 return NULL; 2994 2995 // Try to add block with destructors for RHS expression; 2996 Succ = ConfluenceBlock; 2997 Block = NULL; 2998 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2999 BindToTemporary); 3000 if (badCFG) 3001 return NULL; 3002 3003 if (!RHSBlock && !LHSBlock) { 3004 // If neither LHS nor RHS expression had temporaries to destroy don't create 3005 // more blocks. 3006 Block = ConfluenceBlock; 3007 return Block; 3008 } 3009 3010 Block = createBlock(false); 3011 Block->setTerminator(CFGTerminator(E, true)); 3012 3013 // See if this is a known constant. 3014 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 3015 3016 if (LHSBlock) { 3017 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 3018 } else if (KnownVal.isFalse()) { 3019 addSuccessor(Block, NULL); 3020 } else { 3021 addSuccessor(Block, ConfluenceBlock); 3022 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 3023 } 3024 3025 if (!RHSBlock) 3026 RHSBlock = ConfluenceBlock; 3027 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 3028 3029 return Block; 3030} 3031 3032} // end anonymous namespace 3033 3034/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 3035/// no successors or predecessors. If this is the first block created in the 3036/// CFG, it is automatically set to be the Entry and Exit of the CFG. 3037CFGBlock *CFG::createBlock() { 3038 bool first_block = begin() == end(); 3039 3040 // Create the block. 3041 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 3042 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this); 3043 Blocks.push_back(Mem, BlkBVC); 3044 3045 // If this is the first block, set it as the Entry and Exit. 3046 if (first_block) 3047 Entry = Exit = &back(); 3048 3049 // Return the block. 3050 return &back(); 3051} 3052 3053/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 3054/// CFG is returned to the caller. 3055CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 3056 const BuildOptions &BO) { 3057 CFGBuilder Builder(C, BO); 3058 return Builder.buildCFG(D, Statement); 3059} 3060 3061const CXXDestructorDecl * 3062CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 3063 switch (getKind()) { 3064 case CFGElement::Invalid: 3065 case CFGElement::Statement: 3066 case CFGElement::Initializer: 3067 llvm_unreachable("getDestructorDecl should only be used with " 3068 "ImplicitDtors"); 3069 case CFGElement::AutomaticObjectDtor: { 3070 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 3071 QualType ty = var->getType(); 3072 ty = ty.getNonReferenceType(); 3073 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3074 ty = arrayType->getElementType(); 3075 } 3076 const RecordType *recordType = ty->getAs<RecordType>(); 3077 const CXXRecordDecl *classDecl = 3078 cast<CXXRecordDecl>(recordType->getDecl()); 3079 return classDecl->getDestructor(); 3080 } 3081 case CFGElement::TemporaryDtor: { 3082 const CXXBindTemporaryExpr *bindExpr = 3083 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 3084 const CXXTemporary *temp = bindExpr->getTemporary(); 3085 return temp->getDestructor(); 3086 } 3087 case CFGElement::BaseDtor: 3088 case CFGElement::MemberDtor: 3089 3090 // Not yet supported. 3091 return 0; 3092 } 3093 llvm_unreachable("getKind() returned bogus value"); 3094 return 0; 3095} 3096 3097bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3098 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 3099 QualType ty = cdecl->getType(); 3100 return cast<FunctionType>(ty)->getNoReturnAttr(); 3101 } 3102 return false; 3103} 3104 3105//===----------------------------------------------------------------------===// 3106// CFG: Queries for BlkExprs. 3107//===----------------------------------------------------------------------===// 3108 3109namespace { 3110 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3111} 3112 3113static void FindSubExprAssignments(const Stmt *S, 3114 llvm::SmallPtrSet<const Expr*,50>& Set) { 3115 if (!S) 3116 return; 3117 3118 for (Stmt::const_child_range I = S->children(); I; ++I) { 3119 const Stmt *child = *I; 3120 if (!child) 3121 continue; 3122 3123 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3124 if (B->isAssignmentOp()) Set.insert(B); 3125 3126 FindSubExprAssignments(child, Set); 3127 } 3128} 3129 3130static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3131 BlkExprMapTy* M = new BlkExprMapTy(); 3132 3133 // Look for assignments that are used as subexpressions. These are the only 3134 // assignments that we want to *possibly* register as a block-level 3135 // expression. Basically, if an assignment occurs both in a subexpression and 3136 // at the block-level, it is a block-level expression. 3137 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3138 3139 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3140 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3141 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3142 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3143 3144 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3145 3146 // Iterate over the statements again on identify the Expr* and Stmt* at the 3147 // block-level that are block-level expressions. 3148 3149 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3150 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3151 if (!CS) 3152 continue; 3153 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3154 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3155 3156 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3157 // Assignment expressions that are not nested within another 3158 // expression are really "statements" whose value is never used by 3159 // another expression. 3160 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3161 continue; 3162 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3163 // Special handling for statement expressions. The last statement in 3164 // the statement expression is also a block-level expr. 3165 const CompoundStmt *C = SE->getSubStmt(); 3166 if (!C->body_empty()) { 3167 const Stmt *Last = C->body_back(); 3168 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3169 Last = LastEx->IgnoreParens(); 3170 unsigned x = M->size(); 3171 (*M)[Last] = x; 3172 } 3173 } 3174 3175 unsigned x = M->size(); 3176 (*M)[Exp] = x; 3177 } 3178 } 3179 3180 // Look at terminators. The condition is a block-level expression. 3181 3182 Stmt *S = (*I)->getTerminatorCondition(); 3183 3184 if (S && M->find(S) == M->end()) { 3185 unsigned x = M->size(); 3186 (*M)[S] = x; 3187 } 3188 } 3189 3190 return M; 3191} 3192 3193CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3194 assert(S != NULL); 3195 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3196 3197 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3198 BlkExprMapTy::iterator I = M->find(S); 3199 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3200} 3201 3202unsigned CFG::getNumBlkExprs() { 3203 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3204 return M->size(); 3205 3206 // We assume callers interested in the number of BlkExprs will want 3207 // the map constructed if it doesn't already exist. 3208 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3209 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3210} 3211 3212//===----------------------------------------------------------------------===// 3213// Filtered walking of the CFG. 3214//===----------------------------------------------------------------------===// 3215 3216bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3217 const CFGBlock *From, const CFGBlock *To) { 3218 3219 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3220 // If the 'To' has no label or is labeled but the label isn't a 3221 // CaseStmt then filter this edge. 3222 if (const SwitchStmt *S = 3223 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3224 if (S->isAllEnumCasesCovered()) { 3225 const Stmt *L = To->getLabel(); 3226 if (!L || !isa<CaseStmt>(L)) 3227 return true; 3228 } 3229 } 3230 } 3231 3232 return false; 3233} 3234 3235//===----------------------------------------------------------------------===// 3236// Cleanup: CFG dstor. 3237//===----------------------------------------------------------------------===// 3238 3239CFG::~CFG() { 3240 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3241} 3242 3243//===----------------------------------------------------------------------===// 3244// CFG pretty printing 3245//===----------------------------------------------------------------------===// 3246 3247namespace { 3248 3249class StmtPrinterHelper : public PrinterHelper { 3250 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3251 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3252 StmtMapTy StmtMap; 3253 DeclMapTy DeclMap; 3254 signed currentBlock; 3255 unsigned currentStmt; 3256 const LangOptions &LangOpts; 3257public: 3258 3259 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3260 : currentBlock(0), currentStmt(0), LangOpts(LO) 3261 { 3262 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3263 unsigned j = 1; 3264 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3265 BI != BEnd; ++BI, ++j ) { 3266 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3267 const Stmt *stmt= SE->getStmt(); 3268 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3269 StmtMap[stmt] = P; 3270 3271 switch (stmt->getStmtClass()) { 3272 case Stmt::DeclStmtClass: 3273 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3274 break; 3275 case Stmt::IfStmtClass: { 3276 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3277 if (var) 3278 DeclMap[var] = P; 3279 break; 3280 } 3281 case Stmt::ForStmtClass: { 3282 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3283 if (var) 3284 DeclMap[var] = P; 3285 break; 3286 } 3287 case Stmt::WhileStmtClass: { 3288 const VarDecl *var = 3289 cast<WhileStmt>(stmt)->getConditionVariable(); 3290 if (var) 3291 DeclMap[var] = P; 3292 break; 3293 } 3294 case Stmt::SwitchStmtClass: { 3295 const VarDecl *var = 3296 cast<SwitchStmt>(stmt)->getConditionVariable(); 3297 if (var) 3298 DeclMap[var] = P; 3299 break; 3300 } 3301 case Stmt::CXXCatchStmtClass: { 3302 const VarDecl *var = 3303 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3304 if (var) 3305 DeclMap[var] = P; 3306 break; 3307 } 3308 default: 3309 break; 3310 } 3311 } 3312 } 3313 } 3314 } 3315 3316 3317 virtual ~StmtPrinterHelper() {} 3318 3319 const LangOptions &getLangOpts() const { return LangOpts; } 3320 void setBlockID(signed i) { currentBlock = i; } 3321 void setStmtID(unsigned i) { currentStmt = i; } 3322 3323 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3324 StmtMapTy::iterator I = StmtMap.find(S); 3325 3326 if (I == StmtMap.end()) 3327 return false; 3328 3329 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3330 && I->second.second == currentStmt) { 3331 return false; 3332 } 3333 3334 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3335 return true; 3336 } 3337 3338 bool handleDecl(const Decl *D, raw_ostream &OS) { 3339 DeclMapTy::iterator I = DeclMap.find(D); 3340 3341 if (I == DeclMap.end()) 3342 return false; 3343 3344 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3345 && I->second.second == currentStmt) { 3346 return false; 3347 } 3348 3349 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3350 return true; 3351 } 3352}; 3353} // end anonymous namespace 3354 3355 3356namespace { 3357class CFGBlockTerminatorPrint 3358 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3359 3360 raw_ostream &OS; 3361 StmtPrinterHelper* Helper; 3362 PrintingPolicy Policy; 3363public: 3364 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3365 const PrintingPolicy &Policy) 3366 : OS(os), Helper(helper), Policy(Policy) {} 3367 3368 void VisitIfStmt(IfStmt *I) { 3369 OS << "if "; 3370 I->getCond()->printPretty(OS,Helper,Policy); 3371 } 3372 3373 // Default case. 3374 void VisitStmt(Stmt *Terminator) { 3375 Terminator->printPretty(OS, Helper, Policy); 3376 } 3377 3378 void VisitForStmt(ForStmt *F) { 3379 OS << "for (" ; 3380 if (F->getInit()) 3381 OS << "..."; 3382 OS << "; "; 3383 if (Stmt *C = F->getCond()) 3384 C->printPretty(OS, Helper, Policy); 3385 OS << "; "; 3386 if (F->getInc()) 3387 OS << "..."; 3388 OS << ")"; 3389 } 3390 3391 void VisitWhileStmt(WhileStmt *W) { 3392 OS << "while " ; 3393 if (Stmt *C = W->getCond()) 3394 C->printPretty(OS, Helper, Policy); 3395 } 3396 3397 void VisitDoStmt(DoStmt *D) { 3398 OS << "do ... while "; 3399 if (Stmt *C = D->getCond()) 3400 C->printPretty(OS, Helper, Policy); 3401 } 3402 3403 void VisitSwitchStmt(SwitchStmt *Terminator) { 3404 OS << "switch "; 3405 Terminator->getCond()->printPretty(OS, Helper, Policy); 3406 } 3407 3408 void VisitCXXTryStmt(CXXTryStmt *CS) { 3409 OS << "try ..."; 3410 } 3411 3412 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3413 C->getCond()->printPretty(OS, Helper, Policy); 3414 OS << " ? ... : ..."; 3415 } 3416 3417 void VisitChooseExpr(ChooseExpr *C) { 3418 OS << "__builtin_choose_expr( "; 3419 C->getCond()->printPretty(OS, Helper, Policy); 3420 OS << " )"; 3421 } 3422 3423 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3424 OS << "goto *"; 3425 I->getTarget()->printPretty(OS, Helper, Policy); 3426 } 3427 3428 void VisitBinaryOperator(BinaryOperator* B) { 3429 if (!B->isLogicalOp()) { 3430 VisitExpr(B); 3431 return; 3432 } 3433 3434 B->getLHS()->printPretty(OS, Helper, Policy); 3435 3436 switch (B->getOpcode()) { 3437 case BO_LOr: 3438 OS << " || ..."; 3439 return; 3440 case BO_LAnd: 3441 OS << " && ..."; 3442 return; 3443 default: 3444 llvm_unreachable("Invalid logical operator."); 3445 } 3446 } 3447 3448 void VisitExpr(Expr *E) { 3449 E->printPretty(OS, Helper, Policy); 3450 } 3451}; 3452} // end anonymous namespace 3453 3454static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3455 const CFGElement &E) { 3456 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3457 const Stmt *S = CS->getStmt(); 3458 3459 if (Helper) { 3460 3461 // special printing for statement-expressions. 3462 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3463 const CompoundStmt *Sub = SE->getSubStmt(); 3464 3465 if (Sub->children()) { 3466 OS << "({ ... ; "; 3467 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3468 OS << " })\n"; 3469 return; 3470 } 3471 } 3472 // special printing for comma expressions. 3473 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3474 if (B->getOpcode() == BO_Comma) { 3475 OS << "... , "; 3476 Helper->handledStmt(B->getRHS(),OS); 3477 OS << '\n'; 3478 return; 3479 } 3480 } 3481 } 3482 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3483 3484 if (isa<CXXOperatorCallExpr>(S)) { 3485 OS << " (OperatorCall)"; 3486 } 3487 else if (isa<CXXBindTemporaryExpr>(S)) { 3488 OS << " (BindTemporary)"; 3489 } 3490 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) { 3491 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")"; 3492 } 3493 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) { 3494 OS << " (" << CE->getStmtClassName() << ", " 3495 << CE->getCastKindName() 3496 << ", " << CE->getType().getAsString() 3497 << ")"; 3498 } 3499 3500 // Expressions need a newline. 3501 if (isa<Expr>(S)) 3502 OS << '\n'; 3503 3504 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3505 const CXXCtorInitializer *I = IE->getInitializer(); 3506 if (I->isBaseInitializer()) 3507 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3508 else OS << I->getAnyMember()->getName(); 3509 3510 OS << "("; 3511 if (Expr *IE = I->getInit()) 3512 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3513 OS << ")"; 3514 3515 if (I->isBaseInitializer()) 3516 OS << " (Base initializer)\n"; 3517 else OS << " (Member initializer)\n"; 3518 3519 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3520 const VarDecl *VD = DE->getVarDecl(); 3521 Helper->handleDecl(VD, OS); 3522 3523 const Type* T = VD->getType().getTypePtr(); 3524 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3525 T = RT->getPointeeType().getTypePtr(); 3526 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3527 T = ET; 3528 3529 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3530 OS << " (Implicit destructor)\n"; 3531 3532 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3533 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3534 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3535 OS << " (Base object destructor)\n"; 3536 3537 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3538 const FieldDecl *FD = ME->getFieldDecl(); 3539 3540 const Type *T = FD->getType().getTypePtr(); 3541 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3542 T = ET; 3543 3544 OS << "this->" << FD->getName(); 3545 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3546 OS << " (Member object destructor)\n"; 3547 3548 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3549 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3550 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3551 OS << " (Temporary object destructor)\n"; 3552 } 3553} 3554 3555static void print_block(raw_ostream &OS, const CFG* cfg, 3556 const CFGBlock &B, 3557 StmtPrinterHelper* Helper, bool print_edges, 3558 bool ShowColors) { 3559 3560 if (Helper) 3561 Helper->setBlockID(B.getBlockID()); 3562 3563 // Print the header. 3564 if (ShowColors) 3565 OS.changeColor(raw_ostream::YELLOW, true); 3566 3567 OS << "\n [B" << B.getBlockID(); 3568 3569 if (&B == &cfg->getEntry()) 3570 OS << " (ENTRY)]\n"; 3571 else if (&B == &cfg->getExit()) 3572 OS << " (EXIT)]\n"; 3573 else if (&B == cfg->getIndirectGotoBlock()) 3574 OS << " (INDIRECT GOTO DISPATCH)]\n"; 3575 else 3576 OS << "]\n"; 3577 3578 if (ShowColors) 3579 OS.resetColor(); 3580 3581 // Print the label of this block. 3582 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3583 3584 if (print_edges) 3585 OS << " "; 3586 3587 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3588 OS << L->getName(); 3589 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3590 OS << "case "; 3591 C->getLHS()->printPretty(OS, Helper, 3592 PrintingPolicy(Helper->getLangOpts())); 3593 if (C->getRHS()) { 3594 OS << " ... "; 3595 C->getRHS()->printPretty(OS, Helper, 3596 PrintingPolicy(Helper->getLangOpts())); 3597 } 3598 } else if (isa<DefaultStmt>(Label)) 3599 OS << "default"; 3600 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3601 OS << "catch ("; 3602 if (CS->getExceptionDecl()) 3603 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3604 0); 3605 else 3606 OS << "..."; 3607 OS << ")"; 3608 3609 } else 3610 llvm_unreachable("Invalid label statement in CFGBlock."); 3611 3612 OS << ":\n"; 3613 } 3614 3615 // Iterate through the statements in the block and print them. 3616 unsigned j = 1; 3617 3618 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3619 I != E ; ++I, ++j ) { 3620 3621 // Print the statement # in the basic block and the statement itself. 3622 if (print_edges) 3623 OS << " "; 3624 3625 OS << llvm::format("%3d", j) << ": "; 3626 3627 if (Helper) 3628 Helper->setStmtID(j); 3629 3630 print_elem(OS, Helper, *I); 3631 } 3632 3633 // Print the terminator of this block. 3634 if (B.getTerminator()) { 3635 if (ShowColors) 3636 OS.changeColor(raw_ostream::GREEN); 3637 3638 OS << " T: "; 3639 3640 if (Helper) Helper->setBlockID(-1); 3641 3642 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3643 PrintingPolicy(Helper->getLangOpts())); 3644 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3645 OS << '\n'; 3646 3647 if (ShowColors) 3648 OS.resetColor(); 3649 } 3650 3651 if (print_edges) { 3652 // Print the predecessors of this block. 3653 if (!B.pred_empty()) { 3654 const raw_ostream::Colors Color = raw_ostream::BLUE; 3655 if (ShowColors) 3656 OS.changeColor(Color); 3657 OS << " Preds " ; 3658 if (ShowColors) 3659 OS.resetColor(); 3660 OS << '(' << B.pred_size() << "):"; 3661 unsigned i = 0; 3662 3663 if (ShowColors) 3664 OS.changeColor(Color); 3665 3666 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3667 I != E; ++I, ++i) { 3668 3669 if (i == 8 || (i-8) == 0) 3670 OS << "\n "; 3671 3672 OS << " B" << (*I)->getBlockID(); 3673 } 3674 3675 if (ShowColors) 3676 OS.resetColor(); 3677 3678 OS << '\n'; 3679 } 3680 3681 // Print the successors of this block. 3682 if (!B.succ_empty()) { 3683 const raw_ostream::Colors Color = raw_ostream::MAGENTA; 3684 if (ShowColors) 3685 OS.changeColor(Color); 3686 OS << " Succs "; 3687 if (ShowColors) 3688 OS.resetColor(); 3689 OS << '(' << B.succ_size() << "):"; 3690 unsigned i = 0; 3691 3692 if (ShowColors) 3693 OS.changeColor(Color); 3694 3695 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3696 I != E; ++I, ++i) { 3697 3698 if (i == 8 || (i-8) % 10 == 0) 3699 OS << "\n "; 3700 3701 if (*I) 3702 OS << " B" << (*I)->getBlockID(); 3703 else 3704 OS << " NULL"; 3705 } 3706 3707 if (ShowColors) 3708 OS.resetColor(); 3709 OS << '\n'; 3710 } 3711 } 3712} 3713 3714 3715/// dump - A simple pretty printer of a CFG that outputs to stderr. 3716void CFG::dump(const LangOptions &LO, bool ShowColors) const { 3717 print(llvm::errs(), LO, ShowColors); 3718} 3719 3720/// print - A simple pretty printer of a CFG that outputs to an ostream. 3721void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const { 3722 StmtPrinterHelper Helper(this, LO); 3723 3724 // Print the entry block. 3725 print_block(OS, this, getEntry(), &Helper, true, ShowColors); 3726 3727 // Iterate through the CFGBlocks and print them one by one. 3728 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3729 // Skip the entry block, because we already printed it. 3730 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3731 continue; 3732 3733 print_block(OS, this, **I, &Helper, true, ShowColors); 3734 } 3735 3736 // Print the exit block. 3737 print_block(OS, this, getExit(), &Helper, true, ShowColors); 3738 OS << '\n'; 3739 OS.flush(); 3740} 3741 3742/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3743void CFGBlock::dump(const CFG* cfg, const LangOptions &LO, 3744 bool ShowColors) const { 3745 print(llvm::errs(), cfg, LO, ShowColors); 3746} 3747 3748/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3749/// Generally this will only be called from CFG::print. 3750void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3751 const LangOptions &LO, bool ShowColors) const { 3752 StmtPrinterHelper Helper(cfg, LO); 3753 print_block(OS, cfg, *this, &Helper, true, ShowColors); 3754 OS << '\n'; 3755} 3756 3757/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3758void CFGBlock::printTerminator(raw_ostream &OS, 3759 const LangOptions &LO) const { 3760 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3761 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3762} 3763 3764Stmt *CFGBlock::getTerminatorCondition() { 3765 Stmt *Terminator = this->Terminator; 3766 if (!Terminator) 3767 return NULL; 3768 3769 Expr *E = NULL; 3770 3771 switch (Terminator->getStmtClass()) { 3772 default: 3773 break; 3774 3775 case Stmt::ForStmtClass: 3776 E = cast<ForStmt>(Terminator)->getCond(); 3777 break; 3778 3779 case Stmt::WhileStmtClass: 3780 E = cast<WhileStmt>(Terminator)->getCond(); 3781 break; 3782 3783 case Stmt::DoStmtClass: 3784 E = cast<DoStmt>(Terminator)->getCond(); 3785 break; 3786 3787 case Stmt::IfStmtClass: 3788 E = cast<IfStmt>(Terminator)->getCond(); 3789 break; 3790 3791 case Stmt::ChooseExprClass: 3792 E = cast<ChooseExpr>(Terminator)->getCond(); 3793 break; 3794 3795 case Stmt::IndirectGotoStmtClass: 3796 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3797 break; 3798 3799 case Stmt::SwitchStmtClass: 3800 E = cast<SwitchStmt>(Terminator)->getCond(); 3801 break; 3802 3803 case Stmt::BinaryConditionalOperatorClass: 3804 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3805 break; 3806 3807 case Stmt::ConditionalOperatorClass: 3808 E = cast<ConditionalOperator>(Terminator)->getCond(); 3809 break; 3810 3811 case Stmt::BinaryOperatorClass: // '&&' and '||' 3812 E = cast<BinaryOperator>(Terminator)->getLHS(); 3813 break; 3814 3815 case Stmt::ObjCForCollectionStmtClass: 3816 return Terminator; 3817 } 3818 3819 return E ? E->IgnoreParens() : NULL; 3820} 3821 3822//===----------------------------------------------------------------------===// 3823// CFG Graphviz Visualization 3824//===----------------------------------------------------------------------===// 3825 3826 3827#ifndef NDEBUG 3828static StmtPrinterHelper* GraphHelper; 3829#endif 3830 3831void CFG::viewCFG(const LangOptions &LO) const { 3832#ifndef NDEBUG 3833 StmtPrinterHelper H(this, LO); 3834 GraphHelper = &H; 3835 llvm::ViewGraph(this,"CFG"); 3836 GraphHelper = NULL; 3837#endif 3838} 3839 3840namespace llvm { 3841template<> 3842struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3843 3844 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3845 3846 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 3847 3848#ifndef NDEBUG 3849 std::string OutSStr; 3850 llvm::raw_string_ostream Out(OutSStr); 3851 print_block(Out,Graph, *Node, GraphHelper, false, false); 3852 std::string& OutStr = Out.str(); 3853 3854 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3855 3856 // Process string output to make it nicer... 3857 for (unsigned i = 0; i != OutStr.length(); ++i) 3858 if (OutStr[i] == '\n') { // Left justify 3859 OutStr[i] = '\\'; 3860 OutStr.insert(OutStr.begin()+i+1, 'l'); 3861 } 3862 3863 return OutStr; 3864#else 3865 return ""; 3866#endif 3867 } 3868}; 3869} // end namespace llvm 3870