CFG.cpp revision 8cad3046be06ea73ff8892d947697a21d7a440d3
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "clang/AST/CharUnits.h" 21#include "llvm/Support/GraphWriter.h" 22#include "llvm/Support/Allocator.h" 23#include "llvm/Support/Format.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/OwningPtr.h" 27 28using namespace clang; 29 30namespace { 31 32static SourceLocation GetEndLoc(Decl* D) { 33 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 34 if (Expr* Ex = VD->getInit()) 35 return Ex->getSourceRange().getEnd(); 36 return D->getLocation(); 37} 38 39class CFGBuilder; 40 41/// The CFG builder uses a recursive algorithm to build the CFG. When 42/// we process an expression, sometimes we know that we must add the 43/// subexpressions as block-level expressions. For example: 44/// 45/// exp1 || exp2 46/// 47/// When processing the '||' expression, we know that exp1 and exp2 48/// need to be added as block-level expressions, even though they 49/// might not normally need to be. AddStmtChoice records this 50/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 51/// the builder has an option not to add a subexpression as a 52/// block-level expression. 53/// 54class AddStmtChoice { 55public: 56 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 57 58 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 59 60 bool alwaysAdd(CFGBuilder &builder, 61 const Stmt *stmt) const; 62 63 /// Return a copy of this object, except with the 'always-add' bit 64 /// set as specified. 65 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 66 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 67 } 68 69private: 70 Kind kind; 71}; 72 73/// LocalScope - Node in tree of local scopes created for C++ implicit 74/// destructor calls generation. It contains list of automatic variables 75/// declared in the scope and link to position in previous scope this scope 76/// began in. 77/// 78/// The process of creating local scopes is as follows: 79/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 80/// - Before processing statements in scope (e.g. CompoundStmt) create 81/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 82/// and set CFGBuilder::ScopePos to the end of new scope, 83/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 84/// at this VarDecl, 85/// - For every normal (without jump) end of scope add to CFGBlock destructors 86/// for objects in the current scope, 87/// - For every jump add to CFGBlock destructors for objects 88/// between CFGBuilder::ScopePos and local scope position saved for jump 89/// target. Thanks to C++ restrictions on goto jumps we can be sure that 90/// jump target position will be on the path to root from CFGBuilder::ScopePos 91/// (adding any variable that doesn't need constructor to be called to 92/// LocalScope can break this assumption), 93/// 94class LocalScope { 95public: 96 typedef BumpVector<VarDecl*> AutomaticVarsTy; 97 98 /// const_iterator - Iterates local scope backwards and jumps to previous 99 /// scope on reaching the beginning of currently iterated scope. 100 class const_iterator { 101 const LocalScope* Scope; 102 103 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 104 /// Invalid iterator (with null Scope) has VarIter equal to 0. 105 unsigned VarIter; 106 107 public: 108 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 109 /// Incrementing invalid iterator is allowed and will result in invalid 110 /// iterator. 111 const_iterator() 112 : Scope(NULL), VarIter(0) {} 113 114 /// Create valid iterator. In case when S.Prev is an invalid iterator and 115 /// I is equal to 0, this will create invalid iterator. 116 const_iterator(const LocalScope& S, unsigned I) 117 : Scope(&S), VarIter(I) { 118 // Iterator to "end" of scope is not allowed. Handle it by going up 119 // in scopes tree possibly up to invalid iterator in the root. 120 if (VarIter == 0 && Scope) 121 *this = Scope->Prev; 122 } 123 124 VarDecl* const* operator->() const { 125 assert (Scope && "Dereferencing invalid iterator is not allowed"); 126 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 127 return &Scope->Vars[VarIter - 1]; 128 } 129 VarDecl* operator*() const { 130 return *this->operator->(); 131 } 132 133 const_iterator& operator++() { 134 if (!Scope) 135 return *this; 136 137 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 138 --VarIter; 139 if (VarIter == 0) 140 *this = Scope->Prev; 141 return *this; 142 } 143 const_iterator operator++(int) { 144 const_iterator P = *this; 145 ++*this; 146 return P; 147 } 148 149 bool operator==(const const_iterator& rhs) const { 150 return Scope == rhs.Scope && VarIter == rhs.VarIter; 151 } 152 bool operator!=(const const_iterator& rhs) const { 153 return !(*this == rhs); 154 } 155 156 operator bool() const { 157 return *this != const_iterator(); 158 } 159 160 int distance(const_iterator L); 161 }; 162 163 friend class const_iterator; 164 165private: 166 BumpVectorContext ctx; 167 168 /// Automatic variables in order of declaration. 169 AutomaticVarsTy Vars; 170 /// Iterator to variable in previous scope that was declared just before 171 /// begin of this scope. 172 const_iterator Prev; 173 174public: 175 /// Constructs empty scope linked to previous scope in specified place. 176 LocalScope(BumpVectorContext &ctx, const_iterator P) 177 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 178 179 /// Begin of scope in direction of CFG building (backwards). 180 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 181 182 void addVar(VarDecl* VD) { 183 Vars.push_back(VD, ctx); 184 } 185}; 186 187/// distance - Calculates distance from this to L. L must be reachable from this 188/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 189/// number of scopes between this and L. 190int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 191 int D = 0; 192 const_iterator F = *this; 193 while (F.Scope != L.Scope) { 194 assert (F != const_iterator() 195 && "L iterator is not reachable from F iterator."); 196 D += F.VarIter; 197 F = F.Scope->Prev; 198 } 199 D += F.VarIter - L.VarIter; 200 return D; 201} 202 203/// BlockScopePosPair - Structure for specifying position in CFG during its 204/// build process. It consists of CFGBlock that specifies position in CFG graph 205/// and LocalScope::const_iterator that specifies position in LocalScope graph. 206struct BlockScopePosPair { 207 BlockScopePosPair() : block(0) {} 208 BlockScopePosPair(CFGBlock* b, LocalScope::const_iterator scopePos) 209 : block(b), scopePosition(scopePos) {} 210 211 CFGBlock *block; 212 LocalScope::const_iterator scopePosition; 213}; 214 215/// TryResult - a class representing a variant over the values 216/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 217/// and is used by the CFGBuilder to decide if a branch condition 218/// can be decided up front during CFG construction. 219class TryResult { 220 int X; 221public: 222 TryResult(bool b) : X(b ? 1 : 0) {} 223 TryResult() : X(-1) {} 224 225 bool isTrue() const { return X == 1; } 226 bool isFalse() const { return X == 0; } 227 bool isKnown() const { return X >= 0; } 228 void negate() { 229 assert(isKnown()); 230 X ^= 0x1; 231 } 232}; 233 234/// CFGBuilder - This class implements CFG construction from an AST. 235/// The builder is stateful: an instance of the builder should be used to only 236/// construct a single CFG. 237/// 238/// Example usage: 239/// 240/// CFGBuilder builder; 241/// CFG* cfg = builder.BuildAST(stmt1); 242/// 243/// CFG construction is done via a recursive walk of an AST. We actually parse 244/// the AST in reverse order so that the successor of a basic block is 245/// constructed prior to its predecessor. This allows us to nicely capture 246/// implicit fall-throughs without extra basic blocks. 247/// 248class CFGBuilder { 249 typedef BlockScopePosPair JumpTarget; 250 typedef BlockScopePosPair JumpSource; 251 252 ASTContext *Context; 253 llvm::OwningPtr<CFG> cfg; 254 255 CFGBlock* Block; 256 CFGBlock* Succ; 257 JumpTarget ContinueJumpTarget; 258 JumpTarget BreakJumpTarget; 259 CFGBlock* SwitchTerminatedBlock; 260 CFGBlock* DefaultCaseBlock; 261 CFGBlock* TryTerminatedBlock; 262 263 // Current position in local scope. 264 LocalScope::const_iterator ScopePos; 265 266 // LabelMap records the mapping from Label expressions to their jump targets. 267 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 268 LabelMapTy LabelMap; 269 270 // A list of blocks that end with a "goto" that must be backpatched to their 271 // resolved targets upon completion of CFG construction. 272 typedef std::vector<JumpSource> BackpatchBlocksTy; 273 BackpatchBlocksTy BackpatchBlocks; 274 275 // A list of labels whose address has been taken (for indirect gotos). 276 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 277 LabelSetTy AddressTakenLabels; 278 279 bool badCFG; 280 const CFG::BuildOptions &BuildOpts; 281 282 // State to track for building switch statements. 283 bool switchExclusivelyCovered; 284 Expr::EvalResult *switchCond; 285 286 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 287 const Stmt *lastLookup; 288 289public: 290 explicit CFGBuilder(ASTContext *astContext, 291 const CFG::BuildOptions &buildOpts) 292 : Context(astContext), cfg(new CFG()), // crew a new CFG 293 Block(NULL), Succ(NULL), 294 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 295 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 296 switchExclusivelyCovered(false), switchCond(0), 297 cachedEntry(0), lastLookup(0) {} 298 299 // buildCFG - Used by external clients to construct the CFG. 300 CFG* buildCFG(const Decl *D, Stmt *Statement); 301 302 bool alwaysAdd(const Stmt *stmt); 303 304private: 305 // Visitors to walk an AST and construct the CFG. 306 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 307 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 308 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 309 CFGBlock *VisitBreakStmt(BreakStmt *B); 310 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 311 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 312 AddStmtChoice asc); 313 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 314 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 315 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 316 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 317 AddStmtChoice asc); 318 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 319 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 320 AddStmtChoice asc); 321 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 322 AddStmtChoice asc); 323 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 324 CFGBlock *VisitCaseStmt(CaseStmt *C); 325 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 326 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 327 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 328 AddStmtChoice asc); 329 CFGBlock *VisitContinueStmt(ContinueStmt *C); 330 CFGBlock *VisitDeclStmt(DeclStmt *DS); 331 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 332 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 333 CFGBlock *VisitDoStmt(DoStmt *D); 334 CFGBlock *VisitForStmt(ForStmt *F); 335 CFGBlock *VisitGotoStmt(GotoStmt* G); 336 CFGBlock *VisitIfStmt(IfStmt *I); 337 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 338 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 339 CFGBlock *VisitLabelStmt(LabelStmt *L); 340 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 341 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 342 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 343 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 344 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 345 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 346 CFGBlock *VisitReturnStmt(ReturnStmt* R); 347 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 348 AddStmtChoice asc); 349 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 350 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 351 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 352 CFGBlock *VisitWhileStmt(WhileStmt *W); 353 354 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 355 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 356 CFGBlock *VisitChildren(Stmt* S); 357 358 // Visitors to walk an AST and generate destructors of temporaries in 359 // full expression. 360 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 361 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 362 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 363 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 364 bool BindToTemporary); 365 CFGBlock * 366 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 367 bool BindToTemporary); 368 369 // NYS == Not Yet Supported 370 CFGBlock* NYS() { 371 badCFG = true; 372 return Block; 373 } 374 375 void autoCreateBlock() { if (!Block) Block = createBlock(); } 376 CFGBlock *createBlock(bool add_successor = true); 377 378 CFGBlock *addStmt(Stmt *S) { 379 return Visit(S, AddStmtChoice::AlwaysAdd); 380 } 381 CFGBlock *addInitializer(CXXCtorInitializer *I); 382 void addAutomaticObjDtors(LocalScope::const_iterator B, 383 LocalScope::const_iterator E, Stmt* S); 384 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 385 386 // Local scopes creation. 387 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 388 389 void addLocalScopeForStmt(Stmt* S); 390 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 391 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 392 393 void addLocalScopeAndDtors(Stmt* S); 394 395 // Interface to CFGBlock - adding CFGElements. 396 void appendStmt(CFGBlock *B, const Stmt *S) { 397 if (alwaysAdd(S)) 398 cachedEntry->second = B; 399 400 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 401 } 402 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 403 B->appendInitializer(I, cfg->getBumpVectorContext()); 404 } 405 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 406 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 407 } 408 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 409 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 410 } 411 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 412 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 413 } 414 415 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 416 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 417 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 418 LocalScope::const_iterator E, Stmt* S); 419 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 420 LocalScope::const_iterator B, LocalScope::const_iterator E); 421 422 void addSuccessor(CFGBlock *B, CFGBlock *S) { 423 B->addSuccessor(S, cfg->getBumpVectorContext()); 424 } 425 426 /// Try and evaluate an expression to an integer constant. 427 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 428 if (!BuildOpts.PruneTriviallyFalseEdges) 429 return false; 430 return !S->isTypeDependent() && 431 !S->isValueDependent() && 432 S->Evaluate(outResult, *Context); 433 } 434 435 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 436 /// if we can evaluate to a known value, otherwise return -1. 437 TryResult tryEvaluateBool(Expr *S) { 438 Expr::EvalResult Result; 439 if (!tryEvaluate(S, Result)) 440 return TryResult(); 441 442 if (Result.Val.isInt()) 443 return Result.Val.getInt().getBoolValue(); 444 445 if (Result.Val.isLValue()) { 446 const Expr *e = Result.Val.getLValueBase(); 447 const CharUnits &c = Result.Val.getLValueOffset(); 448 if (!e && c.isZero()) 449 return false; 450 } 451 return TryResult(); 452 } 453 454}; 455 456inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 457 const Stmt *stmt) const { 458 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 459} 460 461bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 462 if (!BuildOpts.forcedBlkExprs) 463 return false; 464 465 if (lastLookup == stmt) { 466 if (cachedEntry) { 467 assert(cachedEntry->first == stmt); 468 return true; 469 } 470 return false; 471 } 472 473 lastLookup = stmt; 474 475 // Perform the lookup! 476 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 477 478 if (!fb) { 479 // No need to update 'cachedEntry', since it will always be null. 480 assert(cachedEntry == 0); 481 return false; 482 } 483 484 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 485 if (itr == fb->end()) { 486 cachedEntry = 0; 487 return false; 488 } 489 490 cachedEntry = &*itr; 491 return true; 492} 493 494// FIXME: Add support for dependent-sized array types in C++? 495// Does it even make sense to build a CFG for an uninstantiated template? 496static const VariableArrayType *FindVA(const Type *t) { 497 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 498 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 499 if (vat->getSizeExpr()) 500 return vat; 501 502 t = vt->getElementType().getTypePtr(); 503 } 504 505 return 0; 506} 507 508/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 509/// arbitrary statement. Examples include a single expression or a function 510/// body (compound statement). The ownership of the returned CFG is 511/// transferred to the caller. If CFG construction fails, this method returns 512/// NULL. 513CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement) { 514 assert(cfg.get()); 515 if (!Statement) 516 return NULL; 517 518 // Create an empty block that will serve as the exit block for the CFG. Since 519 // this is the first block added to the CFG, it will be implicitly registered 520 // as the exit block. 521 Succ = createBlock(); 522 assert(Succ == &cfg->getExit()); 523 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 524 525 if (BuildOpts.AddImplicitDtors) 526 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 527 addImplicitDtorsForDestructor(DD); 528 529 // Visit the statements and create the CFG. 530 CFGBlock *B = addStmt(Statement); 531 532 if (badCFG) 533 return NULL; 534 535 // For C++ constructor add initializers to CFG. 536 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 537 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 538 E = CD->init_rend(); I != E; ++I) { 539 B = addInitializer(*I); 540 if (badCFG) 541 return NULL; 542 } 543 } 544 545 if (B) 546 Succ = B; 547 548 // Backpatch the gotos whose label -> block mappings we didn't know when we 549 // encountered them. 550 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 551 E = BackpatchBlocks.end(); I != E; ++I ) { 552 553 CFGBlock* B = I->block; 554 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 555 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 556 557 // If there is no target for the goto, then we are looking at an 558 // incomplete AST. Handle this by not registering a successor. 559 if (LI == LabelMap.end()) continue; 560 561 JumpTarget JT = LI->second; 562 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 563 JT.scopePosition); 564 addSuccessor(B, JT.block); 565 } 566 567 // Add successors to the Indirect Goto Dispatch block (if we have one). 568 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 569 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 570 E = AddressTakenLabels.end(); I != E; ++I ) { 571 572 // Lookup the target block. 573 LabelMapTy::iterator LI = LabelMap.find(*I); 574 575 // If there is no target block that contains label, then we are looking 576 // at an incomplete AST. Handle this by not registering a successor. 577 if (LI == LabelMap.end()) continue; 578 579 addSuccessor(B, LI->second.block); 580 } 581 582 // Create an empty entry block that has no predecessors. 583 cfg->setEntry(createBlock()); 584 585 return cfg.take(); 586} 587 588/// createBlock - Used to lazily create blocks that are connected 589/// to the current (global) succcessor. 590CFGBlock* CFGBuilder::createBlock(bool add_successor) { 591 CFGBlock* B = cfg->createBlock(); 592 if (add_successor && Succ) 593 addSuccessor(B, Succ); 594 return B; 595} 596 597/// addInitializer - Add C++ base or member initializer element to CFG. 598CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 599 if (!BuildOpts.AddInitializers) 600 return Block; 601 602 bool IsReference = false; 603 bool HasTemporaries = false; 604 605 // Destructors of temporaries in initialization expression should be called 606 // after initialization finishes. 607 Expr *Init = I->getInit(); 608 if (Init) { 609 if (FieldDecl *FD = I->getAnyMember()) 610 IsReference = FD->getType()->isReferenceType(); 611 HasTemporaries = isa<ExprWithCleanups>(Init); 612 613 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 614 // Generate destructors for temporaries in initialization expression. 615 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 616 IsReference); 617 } 618 } 619 620 autoCreateBlock(); 621 appendInitializer(Block, I); 622 623 if (Init) { 624 if (HasTemporaries) { 625 // For expression with temporaries go directly to subexpression to omit 626 // generating destructors for the second time. 627 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 628 } 629 return Visit(Init); 630 } 631 632 return Block; 633} 634 635/// addAutomaticObjDtors - Add to current block automatic objects destructors 636/// for objects in range of local scope positions. Use S as trigger statement 637/// for destructors. 638void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 639 LocalScope::const_iterator E, Stmt* S) { 640 if (!BuildOpts.AddImplicitDtors) 641 return; 642 643 if (B == E) 644 return; 645 646 autoCreateBlock(); 647 appendAutomaticObjDtors(Block, B, E, S); 648} 649 650/// addImplicitDtorsForDestructor - Add implicit destructors generated for 651/// base and member objects in destructor. 652void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 653 assert (BuildOpts.AddImplicitDtors 654 && "Can be called only when dtors should be added"); 655 const CXXRecordDecl *RD = DD->getParent(); 656 657 // At the end destroy virtual base objects. 658 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 659 VE = RD->vbases_end(); VI != VE; ++VI) { 660 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 661 if (!CD->hasTrivialDestructor()) { 662 autoCreateBlock(); 663 appendBaseDtor(Block, VI); 664 } 665 } 666 667 // Before virtual bases destroy direct base objects. 668 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 669 BE = RD->bases_end(); BI != BE; ++BI) { 670 if (!BI->isVirtual()) { 671 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 672 if (!CD->hasTrivialDestructor()) { 673 autoCreateBlock(); 674 appendBaseDtor(Block, BI); 675 } 676 } 677 } 678 679 // First destroy member objects. 680 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 681 FE = RD->field_end(); FI != FE; ++FI) { 682 // Check for constant size array. Set type to array element type. 683 QualType QT = FI->getType(); 684 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 685 if (AT->getSize() == 0) 686 continue; 687 QT = AT->getElementType(); 688 } 689 690 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 691 if (!CD->hasTrivialDestructor()) { 692 autoCreateBlock(); 693 appendMemberDtor(Block, *FI); 694 } 695 } 696} 697 698/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 699/// way return valid LocalScope object. 700LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 701 if (!Scope) { 702 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 703 Scope = alloc.Allocate<LocalScope>(); 704 BumpVectorContext ctx(alloc); 705 new (Scope) LocalScope(ctx, ScopePos); 706 } 707 return Scope; 708} 709 710/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 711/// that should create implicit scope (e.g. if/else substatements). 712void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 713 if (!BuildOpts.AddImplicitDtors) 714 return; 715 716 LocalScope *Scope = 0; 717 718 // For compound statement we will be creating explicit scope. 719 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 720 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 721 ; BI != BE; ++BI) { 722 Stmt *SI = *BI; 723 if (LabelStmt *LS = dyn_cast<LabelStmt>(SI)) 724 SI = LS->getSubStmt(); 725 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 726 Scope = addLocalScopeForDeclStmt(DS, Scope); 727 } 728 return; 729 } 730 731 // For any other statement scope will be implicit and as such will be 732 // interesting only for DeclStmt. 733 if (LabelStmt *LS = dyn_cast<LabelStmt>(S)) 734 S = LS->getSubStmt(); 735 if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) 736 addLocalScopeForDeclStmt(DS); 737} 738 739/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 740/// reuse Scope if not NULL. 741LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 742 LocalScope* Scope) { 743 if (!BuildOpts.AddImplicitDtors) 744 return Scope; 745 746 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 747 ; DI != DE; ++DI) { 748 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 749 Scope = addLocalScopeForVarDecl(VD, Scope); 750 } 751 return Scope; 752} 753 754/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 755/// create add scope for automatic objects and temporary objects bound to 756/// const reference. Will reuse Scope if not NULL. 757LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 758 LocalScope* Scope) { 759 if (!BuildOpts.AddImplicitDtors) 760 return Scope; 761 762 // Check if variable is local. 763 switch (VD->getStorageClass()) { 764 case SC_None: 765 case SC_Auto: 766 case SC_Register: 767 break; 768 default: return Scope; 769 } 770 771 // Check for const references bound to temporary. Set type to pointee. 772 QualType QT = VD->getType(); 773 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 774 QT = RT->getPointeeType(); 775 if (!QT.isConstQualified()) 776 return Scope; 777 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 778 return Scope; 779 } 780 781 // Check for constant size array. Set type to array element type. 782 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 783 if (AT->getSize() == 0) 784 return Scope; 785 QT = AT->getElementType(); 786 } 787 788 // Check if type is a C++ class with non-trivial destructor. 789 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 790 if (!CD->hasTrivialDestructor()) { 791 // Add the variable to scope 792 Scope = createOrReuseLocalScope(Scope); 793 Scope->addVar(VD); 794 ScopePos = Scope->begin(); 795 } 796 return Scope; 797} 798 799/// addLocalScopeAndDtors - For given statement add local scope for it and 800/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 801void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 802 if (!BuildOpts.AddImplicitDtors) 803 return; 804 805 LocalScope::const_iterator scopeBeginPos = ScopePos; 806 addLocalScopeForStmt(S); 807 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 808} 809 810/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 811/// automatic storage duration to CFGBlock's elements vector. Insertion will be 812/// performed in place specified with iterator. 813void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 814 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 815 BumpVectorContext& C = cfg->getBumpVectorContext(); 816 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 817 while (B != E) 818 I = Blk->insertAutomaticObjDtor(I, *B++, S); 819} 820 821/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 822/// automatic storage duration to CFGBlock's elements vector. Elements will be 823/// appended to physical end of the vector which happens to be logical 824/// beginning. 825void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 826 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 827 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 828} 829 830/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 831/// variables with automatic storage duration to CFGBlock's elements vector. 832/// Elements will be prepended to physical beginning of the vector which 833/// happens to be logical end. Use blocks terminator as statement that specifies 834/// destructors call site. 835void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 836 LocalScope::const_iterator B, LocalScope::const_iterator E) { 837 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 838} 839 840/// Visit - Walk the subtree of a statement and add extra 841/// blocks for ternary operators, &&, and ||. We also process "," and 842/// DeclStmts (which may contain nested control-flow). 843CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 844tryAgain: 845 if (!S) { 846 badCFG = true; 847 return 0; 848 } 849 switch (S->getStmtClass()) { 850 default: 851 return VisitStmt(S, asc); 852 853 case Stmt::AddrLabelExprClass: 854 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 855 856 case Stmt::BinaryConditionalOperatorClass: 857 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 858 859 case Stmt::BinaryOperatorClass: 860 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 861 862 case Stmt::BlockExprClass: 863 return VisitBlockExpr(cast<BlockExpr>(S), asc); 864 865 case Stmt::BreakStmtClass: 866 return VisitBreakStmt(cast<BreakStmt>(S)); 867 868 case Stmt::CallExprClass: 869 case Stmt::CXXOperatorCallExprClass: 870 case Stmt::CXXMemberCallExprClass: 871 return VisitCallExpr(cast<CallExpr>(S), asc); 872 873 case Stmt::CaseStmtClass: 874 return VisitCaseStmt(cast<CaseStmt>(S)); 875 876 case Stmt::ChooseExprClass: 877 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 878 879 case Stmt::CompoundStmtClass: 880 return VisitCompoundStmt(cast<CompoundStmt>(S)); 881 882 case Stmt::ConditionalOperatorClass: 883 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 884 885 case Stmt::ContinueStmtClass: 886 return VisitContinueStmt(cast<ContinueStmt>(S)); 887 888 case Stmt::CXXCatchStmtClass: 889 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 890 891 case Stmt::ExprWithCleanupsClass: 892 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 893 894 case Stmt::CXXBindTemporaryExprClass: 895 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 896 897 case Stmt::CXXConstructExprClass: 898 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 899 900 case Stmt::CXXFunctionalCastExprClass: 901 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 902 903 case Stmt::CXXTemporaryObjectExprClass: 904 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 905 906 case Stmt::CXXThrowExprClass: 907 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 908 909 case Stmt::CXXTryStmtClass: 910 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 911 912 case Stmt::CXXForRangeStmtClass: 913 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 914 915 case Stmt::DeclStmtClass: 916 return VisitDeclStmt(cast<DeclStmt>(S)); 917 918 case Stmt::DefaultStmtClass: 919 return VisitDefaultStmt(cast<DefaultStmt>(S)); 920 921 case Stmt::DoStmtClass: 922 return VisitDoStmt(cast<DoStmt>(S)); 923 924 case Stmt::ForStmtClass: 925 return VisitForStmt(cast<ForStmt>(S)); 926 927 case Stmt::GotoStmtClass: 928 return VisitGotoStmt(cast<GotoStmt>(S)); 929 930 case Stmt::IfStmtClass: 931 return VisitIfStmt(cast<IfStmt>(S)); 932 933 case Stmt::ImplicitCastExprClass: 934 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 935 936 case Stmt::IndirectGotoStmtClass: 937 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 938 939 case Stmt::LabelStmtClass: 940 return VisitLabelStmt(cast<LabelStmt>(S)); 941 942 case Stmt::MemberExprClass: 943 return VisitMemberExpr(cast<MemberExpr>(S), asc); 944 945 case Stmt::ObjCAtCatchStmtClass: 946 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 947 948 case Stmt::ObjCAtSynchronizedStmtClass: 949 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 950 951 case Stmt::ObjCAtThrowStmtClass: 952 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 953 954 case Stmt::ObjCAtTryStmtClass: 955 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 956 957 case Stmt::ObjCForCollectionStmtClass: 958 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 959 960 case Stmt::ParenExprClass: 961 S = cast<ParenExpr>(S)->getSubExpr(); 962 goto tryAgain; 963 964 case Stmt::NullStmtClass: 965 return Block; 966 967 case Stmt::ReturnStmtClass: 968 return VisitReturnStmt(cast<ReturnStmt>(S)); 969 970 case Stmt::UnaryExprOrTypeTraitExprClass: 971 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 972 asc); 973 974 case Stmt::StmtExprClass: 975 return VisitStmtExpr(cast<StmtExpr>(S), asc); 976 977 case Stmt::SwitchStmtClass: 978 return VisitSwitchStmt(cast<SwitchStmt>(S)); 979 980 case Stmt::UnaryOperatorClass: 981 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 982 983 case Stmt::WhileStmtClass: 984 return VisitWhileStmt(cast<WhileStmt>(S)); 985 } 986} 987 988CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 989 if (asc.alwaysAdd(*this, S)) { 990 autoCreateBlock(); 991 appendStmt(Block, S); 992 } 993 994 return VisitChildren(S); 995} 996 997/// VisitChildren - Visit the children of a Stmt. 998CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 999 CFGBlock *lastBlock = Block; 1000 for (Stmt::child_range I = Terminator->children(); I; ++I) 1001 if (Stmt *child = *I) 1002 if (CFGBlock *b = Visit(child)) 1003 lastBlock = b; 1004 1005 return lastBlock; 1006} 1007 1008CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1009 AddStmtChoice asc) { 1010 AddressTakenLabels.insert(A->getLabel()); 1011 1012 if (asc.alwaysAdd(*this, A)) { 1013 autoCreateBlock(); 1014 appendStmt(Block, A); 1015 } 1016 1017 return Block; 1018} 1019 1020CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1021 AddStmtChoice asc) { 1022 if (asc.alwaysAdd(*this, U)) { 1023 autoCreateBlock(); 1024 appendStmt(Block, U); 1025 } 1026 1027 return Visit(U->getSubExpr(), AddStmtChoice()); 1028} 1029 1030CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1031 AddStmtChoice asc) { 1032 if (B->isLogicalOp()) { // && or || 1033 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1034 appendStmt(ConfluenceBlock, B); 1035 1036 if (badCFG) 1037 return 0; 1038 1039 // create the block evaluating the LHS 1040 CFGBlock* LHSBlock = createBlock(false); 1041 LHSBlock->setTerminator(B); 1042 1043 // create the block evaluating the RHS 1044 Succ = ConfluenceBlock; 1045 Block = NULL; 1046 CFGBlock* RHSBlock = addStmt(B->getRHS()); 1047 1048 if (RHSBlock) { 1049 if (badCFG) 1050 return 0; 1051 } else { 1052 // Create an empty block for cases where the RHS doesn't require 1053 // any explicit statements in the CFG. 1054 RHSBlock = createBlock(); 1055 } 1056 1057 // See if this is a known constant. 1058 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1059 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1060 KnownVal.negate(); 1061 1062 // Now link the LHSBlock with RHSBlock. 1063 if (B->getOpcode() == BO_LOr) { 1064 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1065 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1066 } else { 1067 assert(B->getOpcode() == BO_LAnd); 1068 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1069 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1070 } 1071 1072 // Generate the blocks for evaluating the LHS. 1073 Block = LHSBlock; 1074 return addStmt(B->getLHS()); 1075 } 1076 1077 if (B->getOpcode() == BO_Comma) { // , 1078 autoCreateBlock(); 1079 appendStmt(Block, B); 1080 addStmt(B->getRHS()); 1081 return addStmt(B->getLHS()); 1082 } 1083 1084 if (B->isAssignmentOp()) { 1085 if (asc.alwaysAdd(*this, B)) { 1086 autoCreateBlock(); 1087 appendStmt(Block, B); 1088 } 1089 Visit(B->getLHS()); 1090 return Visit(B->getRHS()); 1091 } 1092 1093 if (asc.alwaysAdd(*this, B)) { 1094 autoCreateBlock(); 1095 appendStmt(Block, B); 1096 } 1097 1098 CFGBlock *RBlock = Visit(B->getRHS()); 1099 CFGBlock *LBlock = Visit(B->getLHS()); 1100 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1101 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1102 // return RBlock. Otherwise we'll incorrectly return NULL. 1103 return (LBlock ? LBlock : RBlock); 1104} 1105 1106CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1107 if (asc.alwaysAdd(*this, E)) { 1108 autoCreateBlock(); 1109 appendStmt(Block, E); 1110 } 1111 return Block; 1112} 1113 1114CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1115 // "break" is a control-flow statement. Thus we stop processing the current 1116 // block. 1117 if (badCFG) 1118 return 0; 1119 1120 // Now create a new block that ends with the break statement. 1121 Block = createBlock(false); 1122 Block->setTerminator(B); 1123 1124 // If there is no target for the break, then we are looking at an incomplete 1125 // AST. This means that the CFG cannot be constructed. 1126 if (BreakJumpTarget.block) { 1127 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1128 addSuccessor(Block, BreakJumpTarget.block); 1129 } else 1130 badCFG = true; 1131 1132 1133 return Block; 1134} 1135 1136static bool CanThrow(Expr *E, ASTContext &Ctx) { 1137 QualType Ty = E->getType(); 1138 if (Ty->isFunctionPointerType()) 1139 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1140 else if (Ty->isBlockPointerType()) 1141 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1142 1143 const FunctionType *FT = Ty->getAs<FunctionType>(); 1144 if (FT) { 1145 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1146 if (Proto->isNothrow(Ctx)) 1147 return false; 1148 } 1149 return true; 1150} 1151 1152CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1153 // Compute the callee type. 1154 QualType calleeType = C->getCallee()->getType(); 1155 if (calleeType == Context->BoundMemberTy) { 1156 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1157 1158 // We should only get a null bound type if processing a dependent 1159 // CFG. Recover by assuming nothing. 1160 if (!boundType.isNull()) calleeType = boundType; 1161 } 1162 1163 // If this is a call to a no-return function, this stops the block here. 1164 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1165 1166 bool AddEHEdge = false; 1167 1168 // Languages without exceptions are assumed to not throw. 1169 if (Context->getLangOptions().Exceptions) { 1170 if (BuildOpts.AddEHEdges) 1171 AddEHEdge = true; 1172 } 1173 1174 if (FunctionDecl *FD = C->getDirectCallee()) { 1175 if (FD->hasAttr<NoReturnAttr>()) 1176 NoReturn = true; 1177 if (FD->hasAttr<NoThrowAttr>()) 1178 AddEHEdge = false; 1179 } 1180 1181 if (!CanThrow(C->getCallee(), *Context)) 1182 AddEHEdge = false; 1183 1184 if (!NoReturn && !AddEHEdge) 1185 return VisitStmt(C, asc.withAlwaysAdd(true)); 1186 1187 if (Block) { 1188 Succ = Block; 1189 if (badCFG) 1190 return 0; 1191 } 1192 1193 Block = createBlock(!NoReturn); 1194 appendStmt(Block, C); 1195 1196 if (NoReturn) { 1197 // Wire this to the exit block directly. 1198 addSuccessor(Block, &cfg->getExit()); 1199 } 1200 if (AddEHEdge) { 1201 // Add exceptional edges. 1202 if (TryTerminatedBlock) 1203 addSuccessor(Block, TryTerminatedBlock); 1204 else 1205 addSuccessor(Block, &cfg->getExit()); 1206 } 1207 1208 return VisitChildren(C); 1209} 1210 1211CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1212 AddStmtChoice asc) { 1213 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1214 appendStmt(ConfluenceBlock, C); 1215 if (badCFG) 1216 return 0; 1217 1218 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1219 Succ = ConfluenceBlock; 1220 Block = NULL; 1221 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1222 if (badCFG) 1223 return 0; 1224 1225 Succ = ConfluenceBlock; 1226 Block = NULL; 1227 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1228 if (badCFG) 1229 return 0; 1230 1231 Block = createBlock(false); 1232 // See if this is a known constant. 1233 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1234 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1235 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1236 Block->setTerminator(C); 1237 return addStmt(C->getCond()); 1238} 1239 1240 1241CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1242 addLocalScopeAndDtors(C); 1243 CFGBlock* LastBlock = Block; 1244 1245 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1246 I != E; ++I ) { 1247 // If we hit a segment of code just containing ';' (NullStmts), we can 1248 // get a null block back. In such cases, just use the LastBlock 1249 if (CFGBlock *newBlock = addStmt(*I)) 1250 LastBlock = newBlock; 1251 1252 if (badCFG) 1253 return NULL; 1254 } 1255 1256 return LastBlock; 1257} 1258 1259CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1260 AddStmtChoice asc) { 1261 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1262 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1263 1264 // Create the confluence block that will "merge" the results of the ternary 1265 // expression. 1266 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1267 appendStmt(ConfluenceBlock, C); 1268 if (badCFG) 1269 return 0; 1270 1271 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1272 1273 // Create a block for the LHS expression if there is an LHS expression. A 1274 // GCC extension allows LHS to be NULL, causing the condition to be the 1275 // value that is returned instead. 1276 // e.g: x ?: y is shorthand for: x ? x : y; 1277 Succ = ConfluenceBlock; 1278 Block = NULL; 1279 CFGBlock* LHSBlock = 0; 1280 const Expr *trueExpr = C->getTrueExpr(); 1281 if (trueExpr != opaqueValue) { 1282 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1283 if (badCFG) 1284 return 0; 1285 Block = NULL; 1286 } 1287 else 1288 LHSBlock = ConfluenceBlock; 1289 1290 // Create the block for the RHS expression. 1291 Succ = ConfluenceBlock; 1292 CFGBlock* RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1293 if (badCFG) 1294 return 0; 1295 1296 // Create the block that will contain the condition. 1297 Block = createBlock(false); 1298 1299 // See if this is a known constant. 1300 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1301 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1302 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1303 Block->setTerminator(C); 1304 Expr *condExpr = C->getCond(); 1305 1306 if (opaqueValue) { 1307 // Run the condition expression if it's not trivially expressed in 1308 // terms of the opaque value (or if there is no opaque value). 1309 if (condExpr != opaqueValue) 1310 addStmt(condExpr); 1311 1312 // Before that, run the common subexpression if there was one. 1313 // At least one of this or the above will be run. 1314 return addStmt(BCO->getCommon()); 1315 } 1316 1317 return addStmt(condExpr); 1318} 1319 1320CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1321 // Check if the Decl is for an __label__. If so, elide it from the 1322 // CFG entirely. 1323 if (isa<LabelDecl>(*DS->decl_begin())) 1324 return Block; 1325 1326 if (DS->isSingleDecl()) 1327 return VisitDeclSubExpr(DS); 1328 1329 CFGBlock *B = 0; 1330 1331 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1332 typedef llvm::SmallVector<Decl*,10> BufTy; 1333 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1334 1335 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1336 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1337 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1338 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1339 1340 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1341 // automatically freed with the CFG. 1342 DeclGroupRef DG(*I); 1343 Decl *D = *I; 1344 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1345 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1346 1347 // Append the fake DeclStmt to block. 1348 B = VisitDeclSubExpr(DSNew); 1349 } 1350 1351 return B; 1352} 1353 1354/// VisitDeclSubExpr - Utility method to add block-level expressions for 1355/// DeclStmts and initializers in them. 1356CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1357 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1358 1359 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1360 1361 if (!VD) { 1362 autoCreateBlock(); 1363 appendStmt(Block, DS); 1364 return Block; 1365 } 1366 1367 bool IsReference = false; 1368 bool HasTemporaries = false; 1369 1370 // Destructors of temporaries in initialization expression should be called 1371 // after initialization finishes. 1372 Expr *Init = VD->getInit(); 1373 if (Init) { 1374 IsReference = VD->getType()->isReferenceType(); 1375 HasTemporaries = isa<ExprWithCleanups>(Init); 1376 1377 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1378 // Generate destructors for temporaries in initialization expression. 1379 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1380 IsReference); 1381 } 1382 } 1383 1384 autoCreateBlock(); 1385 appendStmt(Block, DS); 1386 1387 if (Init) { 1388 if (HasTemporaries) 1389 // For expression with temporaries go directly to subexpression to omit 1390 // generating destructors for the second time. 1391 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1392 else 1393 Visit(Init); 1394 } 1395 1396 // If the type of VD is a VLA, then we must process its size expressions. 1397 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1398 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1399 Block = addStmt(VA->getSizeExpr()); 1400 1401 // Remove variable from local scope. 1402 if (ScopePos && VD == *ScopePos) 1403 ++ScopePos; 1404 1405 return Block; 1406} 1407 1408CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1409 // We may see an if statement in the middle of a basic block, or it may be the 1410 // first statement we are processing. In either case, we create a new basic 1411 // block. First, we create the blocks for the then...else statements, and 1412 // then we create the block containing the if statement. If we were in the 1413 // middle of a block, we stop processing that block. That block is then the 1414 // implicit successor for the "then" and "else" clauses. 1415 1416 // Save local scope position because in case of condition variable ScopePos 1417 // won't be restored when traversing AST. 1418 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1419 1420 // Create local scope for possible condition variable. 1421 // Store scope position. Add implicit destructor. 1422 if (VarDecl* VD = I->getConditionVariable()) { 1423 LocalScope::const_iterator BeginScopePos = ScopePos; 1424 addLocalScopeForVarDecl(VD); 1425 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1426 } 1427 1428 // The block we were processing is now finished. Make it the successor 1429 // block. 1430 if (Block) { 1431 Succ = Block; 1432 if (badCFG) 1433 return 0; 1434 } 1435 1436 // Process the false branch. 1437 CFGBlock* ElseBlock = Succ; 1438 1439 if (Stmt* Else = I->getElse()) { 1440 SaveAndRestore<CFGBlock*> sv(Succ); 1441 1442 // NULL out Block so that the recursive call to Visit will 1443 // create a new basic block. 1444 Block = NULL; 1445 1446 // If branch is not a compound statement create implicit scope 1447 // and add destructors. 1448 if (!isa<CompoundStmt>(Else)) 1449 addLocalScopeAndDtors(Else); 1450 1451 ElseBlock = addStmt(Else); 1452 1453 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1454 ElseBlock = sv.get(); 1455 else if (Block) { 1456 if (badCFG) 1457 return 0; 1458 } 1459 } 1460 1461 // Process the true branch. 1462 CFGBlock* ThenBlock; 1463 { 1464 Stmt* Then = I->getThen(); 1465 assert(Then); 1466 SaveAndRestore<CFGBlock*> sv(Succ); 1467 Block = NULL; 1468 1469 // If branch is not a compound statement create implicit scope 1470 // and add destructors. 1471 if (!isa<CompoundStmt>(Then)) 1472 addLocalScopeAndDtors(Then); 1473 1474 ThenBlock = addStmt(Then); 1475 1476 if (!ThenBlock) { 1477 // We can reach here if the "then" body has all NullStmts. 1478 // Create an empty block so we can distinguish between true and false 1479 // branches in path-sensitive analyses. 1480 ThenBlock = createBlock(false); 1481 addSuccessor(ThenBlock, sv.get()); 1482 } else if (Block) { 1483 if (badCFG) 1484 return 0; 1485 } 1486 } 1487 1488 // Now create a new block containing the if statement. 1489 Block = createBlock(false); 1490 1491 // Set the terminator of the new block to the If statement. 1492 Block->setTerminator(I); 1493 1494 // See if this is a known constant. 1495 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1496 1497 // Now add the successors. 1498 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1499 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1500 1501 // Add the condition as the last statement in the new block. This may create 1502 // new blocks as the condition may contain control-flow. Any newly created 1503 // blocks will be pointed to be "Block". 1504 Block = addStmt(I->getCond()); 1505 1506 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1507 // and the condition variable initialization to the CFG. 1508 if (VarDecl *VD = I->getConditionVariable()) { 1509 if (Expr *Init = VD->getInit()) { 1510 autoCreateBlock(); 1511 appendStmt(Block, I->getConditionVariableDeclStmt()); 1512 addStmt(Init); 1513 } 1514 } 1515 1516 return Block; 1517} 1518 1519 1520CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1521 // If we were in the middle of a block we stop processing that block. 1522 // 1523 // NOTE: If a "return" appears in the middle of a block, this means that the 1524 // code afterwards is DEAD (unreachable). We still keep a basic block 1525 // for that code; a simple "mark-and-sweep" from the entry block will be 1526 // able to report such dead blocks. 1527 1528 // Create the new block. 1529 Block = createBlock(false); 1530 1531 // The Exit block is the only successor. 1532 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1533 addSuccessor(Block, &cfg->getExit()); 1534 1535 // Add the return statement to the block. This may create new blocks if R 1536 // contains control-flow (short-circuit operations). 1537 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1538} 1539 1540CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1541 // Get the block of the labeled statement. Add it to our map. 1542 addStmt(L->getSubStmt()); 1543 CFGBlock *LabelBlock = Block; 1544 1545 if (!LabelBlock) // This can happen when the body is empty, i.e. 1546 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1547 1548 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1549 "label already in map"); 1550 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1551 1552 // Labels partition blocks, so this is the end of the basic block we were 1553 // processing (L is the block's label). Because this is label (and we have 1554 // already processed the substatement) there is no extra control-flow to worry 1555 // about. 1556 LabelBlock->setLabel(L); 1557 if (badCFG) 1558 return 0; 1559 1560 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1561 Block = NULL; 1562 1563 // This block is now the implicit successor of other blocks. 1564 Succ = LabelBlock; 1565 1566 return LabelBlock; 1567} 1568 1569CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1570 // Goto is a control-flow statement. Thus we stop processing the current 1571 // block and create a new one. 1572 1573 Block = createBlock(false); 1574 Block->setTerminator(G); 1575 1576 // If we already know the mapping to the label block add the successor now. 1577 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1578 1579 if (I == LabelMap.end()) 1580 // We will need to backpatch this block later. 1581 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1582 else { 1583 JumpTarget JT = I->second; 1584 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1585 addSuccessor(Block, JT.block); 1586 } 1587 1588 return Block; 1589} 1590 1591CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1592 CFGBlock* LoopSuccessor = NULL; 1593 1594 // Save local scope position because in case of condition variable ScopePos 1595 // won't be restored when traversing AST. 1596 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1597 1598 // Create local scope for init statement and possible condition variable. 1599 // Add destructor for init statement and condition variable. 1600 // Store scope position for continue statement. 1601 if (Stmt* Init = F->getInit()) 1602 addLocalScopeForStmt(Init); 1603 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1604 1605 if (VarDecl* VD = F->getConditionVariable()) 1606 addLocalScopeForVarDecl(VD); 1607 LocalScope::const_iterator ContinueScopePos = ScopePos; 1608 1609 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1610 1611 // "for" is a control-flow statement. Thus we stop processing the current 1612 // block. 1613 if (Block) { 1614 if (badCFG) 1615 return 0; 1616 LoopSuccessor = Block; 1617 } else 1618 LoopSuccessor = Succ; 1619 1620 // Save the current value for the break targets. 1621 // All breaks should go to the code following the loop. 1622 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1623 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1624 1625 // Because of short-circuit evaluation, the condition of the loop can span 1626 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1627 // evaluate the condition. 1628 CFGBlock* ExitConditionBlock = createBlock(false); 1629 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1630 1631 // Set the terminator for the "exit" condition block. 1632 ExitConditionBlock->setTerminator(F); 1633 1634 // Now add the actual condition to the condition block. Because the condition 1635 // itself may contain control-flow, new blocks may be created. 1636 if (Stmt* C = F->getCond()) { 1637 Block = ExitConditionBlock; 1638 EntryConditionBlock = addStmt(C); 1639 if (badCFG) 1640 return 0; 1641 assert(Block == EntryConditionBlock || 1642 (Block == 0 && EntryConditionBlock == Succ)); 1643 1644 // If this block contains a condition variable, add both the condition 1645 // variable and initializer to the CFG. 1646 if (VarDecl *VD = F->getConditionVariable()) { 1647 if (Expr *Init = VD->getInit()) { 1648 autoCreateBlock(); 1649 appendStmt(Block, F->getConditionVariableDeclStmt()); 1650 EntryConditionBlock = addStmt(Init); 1651 assert(Block == EntryConditionBlock); 1652 } 1653 } 1654 1655 if (Block) { 1656 if (badCFG) 1657 return 0; 1658 } 1659 } 1660 1661 // The condition block is the implicit successor for the loop body as well as 1662 // any code above the loop. 1663 Succ = EntryConditionBlock; 1664 1665 // See if this is a known constant. 1666 TryResult KnownVal(true); 1667 1668 if (F->getCond()) 1669 KnownVal = tryEvaluateBool(F->getCond()); 1670 1671 // Now create the loop body. 1672 { 1673 assert(F->getBody()); 1674 1675 // Save the current values for Block, Succ, and continue targets. 1676 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1677 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1678 1679 // Create a new block to contain the (bottom) of the loop body. 1680 Block = NULL; 1681 1682 // Loop body should end with destructor of Condition variable (if any). 1683 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1684 1685 if (Stmt* I = F->getInc()) { 1686 // Generate increment code in its own basic block. This is the target of 1687 // continue statements. 1688 Succ = addStmt(I); 1689 } else { 1690 // No increment code. Create a special, empty, block that is used as the 1691 // target block for "looping back" to the start of the loop. 1692 assert(Succ == EntryConditionBlock); 1693 Succ = Block ? Block : createBlock(); 1694 } 1695 1696 // Finish up the increment (or empty) block if it hasn't been already. 1697 if (Block) { 1698 assert(Block == Succ); 1699 if (badCFG) 1700 return 0; 1701 Block = 0; 1702 } 1703 1704 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1705 1706 // The starting block for the loop increment is the block that should 1707 // represent the 'loop target' for looping back to the start of the loop. 1708 ContinueJumpTarget.block->setLoopTarget(F); 1709 1710 // If body is not a compound statement create implicit scope 1711 // and add destructors. 1712 if (!isa<CompoundStmt>(F->getBody())) 1713 addLocalScopeAndDtors(F->getBody()); 1714 1715 // Now populate the body block, and in the process create new blocks as we 1716 // walk the body of the loop. 1717 CFGBlock* BodyBlock = addStmt(F->getBody()); 1718 1719 if (!BodyBlock) 1720 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1721 else if (badCFG) 1722 return 0; 1723 1724 // This new body block is a successor to our "exit" condition block. 1725 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1726 } 1727 1728 // Link up the condition block with the code that follows the loop. (the 1729 // false branch). 1730 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1731 1732 // If the loop contains initialization, create a new block for those 1733 // statements. This block can also contain statements that precede the loop. 1734 if (Stmt* I = F->getInit()) { 1735 Block = createBlock(); 1736 return addStmt(I); 1737 } 1738 1739 // There is no loop initialization. We are thus basically a while loop. 1740 // NULL out Block to force lazy block construction. 1741 Block = NULL; 1742 Succ = EntryConditionBlock; 1743 return EntryConditionBlock; 1744} 1745 1746CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1747 if (asc.alwaysAdd(*this, M)) { 1748 autoCreateBlock(); 1749 appendStmt(Block, M); 1750 } 1751 return Visit(M->getBase()); 1752} 1753 1754CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1755 // Objective-C fast enumeration 'for' statements: 1756 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1757 // 1758 // for ( Type newVariable in collection_expression ) { statements } 1759 // 1760 // becomes: 1761 // 1762 // prologue: 1763 // 1. collection_expression 1764 // T. jump to loop_entry 1765 // loop_entry: 1766 // 1. side-effects of element expression 1767 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1768 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1769 // TB: 1770 // statements 1771 // T. jump to loop_entry 1772 // FB: 1773 // what comes after 1774 // 1775 // and 1776 // 1777 // Type existingItem; 1778 // for ( existingItem in expression ) { statements } 1779 // 1780 // becomes: 1781 // 1782 // the same with newVariable replaced with existingItem; the binding works 1783 // the same except that for one ObjCForCollectionStmt::getElement() returns 1784 // a DeclStmt and the other returns a DeclRefExpr. 1785 // 1786 1787 CFGBlock* LoopSuccessor = 0; 1788 1789 if (Block) { 1790 if (badCFG) 1791 return 0; 1792 LoopSuccessor = Block; 1793 Block = 0; 1794 } else 1795 LoopSuccessor = Succ; 1796 1797 // Build the condition blocks. 1798 CFGBlock* ExitConditionBlock = createBlock(false); 1799 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1800 1801 // Set the terminator for the "exit" condition block. 1802 ExitConditionBlock->setTerminator(S); 1803 1804 // The last statement in the block should be the ObjCForCollectionStmt, which 1805 // performs the actual binding to 'element' and determines if there are any 1806 // more items in the collection. 1807 appendStmt(ExitConditionBlock, S); 1808 Block = ExitConditionBlock; 1809 1810 // Walk the 'element' expression to see if there are any side-effects. We 1811 // generate new blocks as necessary. We DON'T add the statement by default to 1812 // the CFG unless it contains control-flow. 1813 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1814 if (Block) { 1815 if (badCFG) 1816 return 0; 1817 Block = 0; 1818 } 1819 1820 // The condition block is the implicit successor for the loop body as well as 1821 // any code above the loop. 1822 Succ = EntryConditionBlock; 1823 1824 // Now create the true branch. 1825 { 1826 // Save the current values for Succ, continue and break targets. 1827 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1828 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1829 save_break(BreakJumpTarget); 1830 1831 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1832 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1833 1834 CFGBlock* BodyBlock = addStmt(S->getBody()); 1835 1836 if (!BodyBlock) 1837 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1838 else if (Block) { 1839 if (badCFG) 1840 return 0; 1841 } 1842 1843 // This new body block is a successor to our "exit" condition block. 1844 addSuccessor(ExitConditionBlock, BodyBlock); 1845 } 1846 1847 // Link up the condition block with the code that follows the loop. 1848 // (the false branch). 1849 addSuccessor(ExitConditionBlock, LoopSuccessor); 1850 1851 // Now create a prologue block to contain the collection expression. 1852 Block = createBlock(); 1853 return addStmt(S->getCollection()); 1854} 1855 1856CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1857 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1858 1859 // Inline the body. 1860 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1861 1862 // The sync body starts its own basic block. This makes it a little easier 1863 // for diagnostic clients. 1864 if (SyncBlock) { 1865 if (badCFG) 1866 return 0; 1867 1868 Block = 0; 1869 Succ = SyncBlock; 1870 } 1871 1872 // Add the @synchronized to the CFG. 1873 autoCreateBlock(); 1874 appendStmt(Block, S); 1875 1876 // Inline the sync expression. 1877 return addStmt(S->getSynchExpr()); 1878} 1879 1880CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1881 // FIXME 1882 return NYS(); 1883} 1884 1885CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1886 CFGBlock* LoopSuccessor = NULL; 1887 1888 // Save local scope position because in case of condition variable ScopePos 1889 // won't be restored when traversing AST. 1890 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1891 1892 // Create local scope for possible condition variable. 1893 // Store scope position for continue statement. 1894 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1895 if (VarDecl* VD = W->getConditionVariable()) { 1896 addLocalScopeForVarDecl(VD); 1897 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1898 } 1899 1900 // "while" is a control-flow statement. Thus we stop processing the current 1901 // block. 1902 if (Block) { 1903 if (badCFG) 1904 return 0; 1905 LoopSuccessor = Block; 1906 Block = 0; 1907 } else 1908 LoopSuccessor = Succ; 1909 1910 // Because of short-circuit evaluation, the condition of the loop can span 1911 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1912 // evaluate the condition. 1913 CFGBlock* ExitConditionBlock = createBlock(false); 1914 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1915 1916 // Set the terminator for the "exit" condition block. 1917 ExitConditionBlock->setTerminator(W); 1918 1919 // Now add the actual condition to the condition block. Because the condition 1920 // itself may contain control-flow, new blocks may be created. Thus we update 1921 // "Succ" after adding the condition. 1922 if (Stmt* C = W->getCond()) { 1923 Block = ExitConditionBlock; 1924 EntryConditionBlock = addStmt(C); 1925 // The condition might finish the current 'Block'. 1926 Block = EntryConditionBlock; 1927 1928 // If this block contains a condition variable, add both the condition 1929 // variable and initializer to the CFG. 1930 if (VarDecl *VD = W->getConditionVariable()) { 1931 if (Expr *Init = VD->getInit()) { 1932 autoCreateBlock(); 1933 appendStmt(Block, W->getConditionVariableDeclStmt()); 1934 EntryConditionBlock = addStmt(Init); 1935 assert(Block == EntryConditionBlock); 1936 } 1937 } 1938 1939 if (Block) { 1940 if (badCFG) 1941 return 0; 1942 } 1943 } 1944 1945 // The condition block is the implicit successor for the loop body as well as 1946 // any code above the loop. 1947 Succ = EntryConditionBlock; 1948 1949 // See if this is a known constant. 1950 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1951 1952 // Process the loop body. 1953 { 1954 assert(W->getBody()); 1955 1956 // Save the current values for Block, Succ, and continue and break targets 1957 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1958 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1959 save_break(BreakJumpTarget); 1960 1961 // Create an empty block to represent the transition block for looping back 1962 // to the head of the loop. 1963 Block = 0; 1964 assert(Succ == EntryConditionBlock); 1965 Succ = createBlock(); 1966 Succ->setLoopTarget(W); 1967 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1968 1969 // All breaks should go to the code following the loop. 1970 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1971 1972 // NULL out Block to force lazy instantiation of blocks for the body. 1973 Block = NULL; 1974 1975 // Loop body should end with destructor of Condition variable (if any). 1976 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1977 1978 // If body is not a compound statement create implicit scope 1979 // and add destructors. 1980 if (!isa<CompoundStmt>(W->getBody())) 1981 addLocalScopeAndDtors(W->getBody()); 1982 1983 // Create the body. The returned block is the entry to the loop body. 1984 CFGBlock* BodyBlock = addStmt(W->getBody()); 1985 1986 if (!BodyBlock) 1987 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 1988 else if (Block) { 1989 if (badCFG) 1990 return 0; 1991 } 1992 1993 // Add the loop body entry as a successor to the condition. 1994 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1995 } 1996 1997 // Link up the condition block with the code that follows the loop. (the 1998 // false branch). 1999 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2000 2001 // There can be no more statements in the condition block since we loop back 2002 // to this block. NULL out Block to force lazy creation of another block. 2003 Block = NULL; 2004 2005 // Return the condition block, which is the dominating block for the loop. 2006 Succ = EntryConditionBlock; 2007 return EntryConditionBlock; 2008} 2009 2010 2011CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 2012 // FIXME: For now we pretend that @catch and the code it contains does not 2013 // exit. 2014 return Block; 2015} 2016 2017CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 2018 // FIXME: This isn't complete. We basically treat @throw like a return 2019 // statement. 2020 2021 // If we were in the middle of a block we stop processing that block. 2022 if (badCFG) 2023 return 0; 2024 2025 // Create the new block. 2026 Block = createBlock(false); 2027 2028 // The Exit block is the only successor. 2029 addSuccessor(Block, &cfg->getExit()); 2030 2031 // Add the statement to the block. This may create new blocks if S contains 2032 // control-flow (short-circuit operations). 2033 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2034} 2035 2036CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 2037 // If we were in the middle of a block we stop processing that block. 2038 if (badCFG) 2039 return 0; 2040 2041 // Create the new block. 2042 Block = createBlock(false); 2043 2044 if (TryTerminatedBlock) 2045 // The current try statement is the only successor. 2046 addSuccessor(Block, TryTerminatedBlock); 2047 else 2048 // otherwise the Exit block is the only successor. 2049 addSuccessor(Block, &cfg->getExit()); 2050 2051 // Add the statement to the block. This may create new blocks if S contains 2052 // control-flow (short-circuit operations). 2053 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2054} 2055 2056CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 2057 CFGBlock* LoopSuccessor = NULL; 2058 2059 // "do...while" is a control-flow statement. Thus we stop processing the 2060 // current block. 2061 if (Block) { 2062 if (badCFG) 2063 return 0; 2064 LoopSuccessor = Block; 2065 } else 2066 LoopSuccessor = Succ; 2067 2068 // Because of short-circuit evaluation, the condition of the loop can span 2069 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2070 // evaluate the condition. 2071 CFGBlock* ExitConditionBlock = createBlock(false); 2072 CFGBlock* EntryConditionBlock = ExitConditionBlock; 2073 2074 // Set the terminator for the "exit" condition block. 2075 ExitConditionBlock->setTerminator(D); 2076 2077 // Now add the actual condition to the condition block. Because the condition 2078 // itself may contain control-flow, new blocks may be created. 2079 if (Stmt* C = D->getCond()) { 2080 Block = ExitConditionBlock; 2081 EntryConditionBlock = addStmt(C); 2082 if (Block) { 2083 if (badCFG) 2084 return 0; 2085 } 2086 } 2087 2088 // The condition block is the implicit successor for the loop body. 2089 Succ = EntryConditionBlock; 2090 2091 // See if this is a known constant. 2092 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2093 2094 // Process the loop body. 2095 CFGBlock* BodyBlock = NULL; 2096 { 2097 assert(D->getBody()); 2098 2099 // Save the current values for Block, Succ, and continue and break targets 2100 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2101 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2102 save_break(BreakJumpTarget); 2103 2104 // All continues within this loop should go to the condition block 2105 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2106 2107 // All breaks should go to the code following the loop. 2108 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2109 2110 // NULL out Block to force lazy instantiation of blocks for the body. 2111 Block = NULL; 2112 2113 // If body is not a compound statement create implicit scope 2114 // and add destructors. 2115 if (!isa<CompoundStmt>(D->getBody())) 2116 addLocalScopeAndDtors(D->getBody()); 2117 2118 // Create the body. The returned block is the entry to the loop body. 2119 BodyBlock = addStmt(D->getBody()); 2120 2121 if (!BodyBlock) 2122 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2123 else if (Block) { 2124 if (badCFG) 2125 return 0; 2126 } 2127 2128 if (!KnownVal.isFalse()) { 2129 // Add an intermediate block between the BodyBlock and the 2130 // ExitConditionBlock to represent the "loop back" transition. Create an 2131 // empty block to represent the transition block for looping back to the 2132 // head of the loop. 2133 // FIXME: Can we do this more efficiently without adding another block? 2134 Block = NULL; 2135 Succ = BodyBlock; 2136 CFGBlock *LoopBackBlock = createBlock(); 2137 LoopBackBlock->setLoopTarget(D); 2138 2139 // Add the loop body entry as a successor to the condition. 2140 addSuccessor(ExitConditionBlock, LoopBackBlock); 2141 } 2142 else 2143 addSuccessor(ExitConditionBlock, NULL); 2144 } 2145 2146 // Link up the condition block with the code that follows the loop. 2147 // (the false branch). 2148 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2149 2150 // There can be no more statements in the body block(s) since we loop back to 2151 // the body. NULL out Block to force lazy creation of another block. 2152 Block = NULL; 2153 2154 // Return the loop body, which is the dominating block for the loop. 2155 Succ = BodyBlock; 2156 return BodyBlock; 2157} 2158 2159CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2160 // "continue" is a control-flow statement. Thus we stop processing the 2161 // current block. 2162 if (badCFG) 2163 return 0; 2164 2165 // Now create a new block that ends with the continue statement. 2166 Block = createBlock(false); 2167 Block->setTerminator(C); 2168 2169 // If there is no target for the continue, then we are looking at an 2170 // incomplete AST. This means the CFG cannot be constructed. 2171 if (ContinueJumpTarget.block) { 2172 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2173 addSuccessor(Block, ContinueJumpTarget.block); 2174 } else 2175 badCFG = true; 2176 2177 return Block; 2178} 2179 2180CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2181 AddStmtChoice asc) { 2182 2183 if (asc.alwaysAdd(*this, E)) { 2184 autoCreateBlock(); 2185 appendStmt(Block, E); 2186 } 2187 2188 // VLA types have expressions that must be evaluated. 2189 CFGBlock *lastBlock = Block; 2190 2191 if (E->isArgumentType()) { 2192 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2193 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2194 lastBlock = addStmt(VA->getSizeExpr()); 2195 } 2196 2197 return lastBlock; 2198} 2199 2200/// VisitStmtExpr - Utility method to handle (nested) statement 2201/// expressions (a GCC extension). 2202CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2203 if (asc.alwaysAdd(*this, SE)) { 2204 autoCreateBlock(); 2205 appendStmt(Block, SE); 2206 } 2207 return VisitCompoundStmt(SE->getSubStmt()); 2208} 2209 2210CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2211 // "switch" is a control-flow statement. Thus we stop processing the current 2212 // block. 2213 CFGBlock* SwitchSuccessor = NULL; 2214 2215 // Save local scope position because in case of condition variable ScopePos 2216 // won't be restored when traversing AST. 2217 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2218 2219 // Create local scope for possible condition variable. 2220 // Store scope position. Add implicit destructor. 2221 if (VarDecl* VD = Terminator->getConditionVariable()) { 2222 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2223 addLocalScopeForVarDecl(VD); 2224 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2225 } 2226 2227 if (Block) { 2228 if (badCFG) 2229 return 0; 2230 SwitchSuccessor = Block; 2231 } else SwitchSuccessor = Succ; 2232 2233 // Save the current "switch" context. 2234 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2235 save_default(DefaultCaseBlock); 2236 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2237 2238 // Set the "default" case to be the block after the switch statement. If the 2239 // switch statement contains a "default:", this value will be overwritten with 2240 // the block for that code. 2241 DefaultCaseBlock = SwitchSuccessor; 2242 2243 // Create a new block that will contain the switch statement. 2244 SwitchTerminatedBlock = createBlock(false); 2245 2246 // Now process the switch body. The code after the switch is the implicit 2247 // successor. 2248 Succ = SwitchSuccessor; 2249 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2250 2251 // When visiting the body, the case statements should automatically get linked 2252 // up to the switch. We also don't keep a pointer to the body, since all 2253 // control-flow from the switch goes to case/default statements. 2254 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2255 Block = NULL; 2256 2257 // For pruning unreachable case statements, save the current state 2258 // for tracking the condition value. 2259 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2260 false); 2261 2262 // Determine if the switch condition can be explicitly evaluated. 2263 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2264 Expr::EvalResult result; 2265 bool b = tryEvaluate(Terminator->getCond(), result); 2266 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2267 b ? &result : 0); 2268 2269 // If body is not a compound statement create implicit scope 2270 // and add destructors. 2271 if (!isa<CompoundStmt>(Terminator->getBody())) 2272 addLocalScopeAndDtors(Terminator->getBody()); 2273 2274 addStmt(Terminator->getBody()); 2275 if (Block) { 2276 if (badCFG) 2277 return 0; 2278 } 2279 2280 // If we have no "default:" case, the default transition is to the code 2281 // following the switch body. Moreover, take into account if all the 2282 // cases of a switch are covered (e.g., switching on an enum value). 2283 addSuccessor(SwitchTerminatedBlock, 2284 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2285 ? 0 : DefaultCaseBlock); 2286 2287 // Add the terminator and condition in the switch block. 2288 SwitchTerminatedBlock->setTerminator(Terminator); 2289 Block = SwitchTerminatedBlock; 2290 Block = addStmt(Terminator->getCond()); 2291 2292 // Finally, if the SwitchStmt contains a condition variable, add both the 2293 // SwitchStmt and the condition variable initialization to the CFG. 2294 if (VarDecl *VD = Terminator->getConditionVariable()) { 2295 if (Expr *Init = VD->getInit()) { 2296 autoCreateBlock(); 2297 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2298 addStmt(Init); 2299 } 2300 } 2301 2302 return Block; 2303} 2304 2305static bool shouldAddCase(bool &switchExclusivelyCovered, 2306 const Expr::EvalResult *switchCond, 2307 const CaseStmt *CS, 2308 ASTContext &Ctx) { 2309 if (!switchCond) 2310 return true; 2311 2312 bool addCase = false; 2313 2314 if (!switchExclusivelyCovered) { 2315 if (switchCond->Val.isInt()) { 2316 // Evaluate the LHS of the case value. 2317 Expr::EvalResult V1; 2318 CS->getLHS()->Evaluate(V1, Ctx); 2319 assert(V1.Val.isInt()); 2320 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2321 const llvm::APSInt &lhsInt = V1.Val.getInt(); 2322 2323 if (condInt == lhsInt) { 2324 addCase = true; 2325 switchExclusivelyCovered = true; 2326 } 2327 else if (condInt < lhsInt) { 2328 if (const Expr *RHS = CS->getRHS()) { 2329 // Evaluate the RHS of the case value. 2330 Expr::EvalResult V2; 2331 RHS->Evaluate(V2, Ctx); 2332 assert(V2.Val.isInt()); 2333 if (V2.Val.getInt() <= condInt) { 2334 addCase = true; 2335 switchExclusivelyCovered = true; 2336 } 2337 } 2338 } 2339 } 2340 else 2341 addCase = true; 2342 } 2343 return addCase; 2344} 2345 2346CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2347 // CaseStmts are essentially labels, so they are the first statement in a 2348 // block. 2349 CFGBlock *TopBlock = 0, *LastBlock = 0; 2350 2351 if (Stmt *Sub = CS->getSubStmt()) { 2352 // For deeply nested chains of CaseStmts, instead of doing a recursion 2353 // (which can blow out the stack), manually unroll and create blocks 2354 // along the way. 2355 while (isa<CaseStmt>(Sub)) { 2356 CFGBlock *currentBlock = createBlock(false); 2357 currentBlock->setLabel(CS); 2358 2359 if (TopBlock) 2360 addSuccessor(LastBlock, currentBlock); 2361 else 2362 TopBlock = currentBlock; 2363 2364 addSuccessor(SwitchTerminatedBlock, 2365 shouldAddCase(switchExclusivelyCovered, switchCond, 2366 CS, *Context) 2367 ? currentBlock : 0); 2368 2369 LastBlock = currentBlock; 2370 CS = cast<CaseStmt>(Sub); 2371 Sub = CS->getSubStmt(); 2372 } 2373 2374 addStmt(Sub); 2375 } 2376 2377 CFGBlock* CaseBlock = Block; 2378 if (!CaseBlock) 2379 CaseBlock = createBlock(); 2380 2381 // Cases statements partition blocks, so this is the top of the basic block we 2382 // were processing (the "case XXX:" is the label). 2383 CaseBlock->setLabel(CS); 2384 2385 if (badCFG) 2386 return 0; 2387 2388 // Add this block to the list of successors for the block with the switch 2389 // statement. 2390 assert(SwitchTerminatedBlock); 2391 addSuccessor(SwitchTerminatedBlock, 2392 shouldAddCase(switchExclusivelyCovered, switchCond, 2393 CS, *Context) 2394 ? CaseBlock : 0); 2395 2396 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2397 Block = NULL; 2398 2399 if (TopBlock) { 2400 addSuccessor(LastBlock, CaseBlock); 2401 Succ = TopBlock; 2402 } else { 2403 // This block is now the implicit successor of other blocks. 2404 Succ = CaseBlock; 2405 } 2406 2407 return Succ; 2408} 2409 2410CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2411 if (Terminator->getSubStmt()) 2412 addStmt(Terminator->getSubStmt()); 2413 2414 DefaultCaseBlock = Block; 2415 2416 if (!DefaultCaseBlock) 2417 DefaultCaseBlock = createBlock(); 2418 2419 // Default statements partition blocks, so this is the top of the basic block 2420 // we were processing (the "default:" is the label). 2421 DefaultCaseBlock->setLabel(Terminator); 2422 2423 if (badCFG) 2424 return 0; 2425 2426 // Unlike case statements, we don't add the default block to the successors 2427 // for the switch statement immediately. This is done when we finish 2428 // processing the switch statement. This allows for the default case 2429 // (including a fall-through to the code after the switch statement) to always 2430 // be the last successor of a switch-terminated block. 2431 2432 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2433 Block = NULL; 2434 2435 // This block is now the implicit successor of other blocks. 2436 Succ = DefaultCaseBlock; 2437 2438 return DefaultCaseBlock; 2439} 2440 2441CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2442 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2443 // current block. 2444 CFGBlock* TrySuccessor = NULL; 2445 2446 if (Block) { 2447 if (badCFG) 2448 return 0; 2449 TrySuccessor = Block; 2450 } else TrySuccessor = Succ; 2451 2452 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2453 2454 // Create a new block that will contain the try statement. 2455 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2456 // Add the terminator in the try block. 2457 NewTryTerminatedBlock->setTerminator(Terminator); 2458 2459 bool HasCatchAll = false; 2460 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2461 // The code after the try is the implicit successor. 2462 Succ = TrySuccessor; 2463 CXXCatchStmt *CS = Terminator->getHandler(h); 2464 if (CS->getExceptionDecl() == 0) { 2465 HasCatchAll = true; 2466 } 2467 Block = NULL; 2468 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2469 if (CatchBlock == 0) 2470 return 0; 2471 // Add this block to the list of successors for the block with the try 2472 // statement. 2473 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2474 } 2475 if (!HasCatchAll) { 2476 if (PrevTryTerminatedBlock) 2477 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2478 else 2479 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2480 } 2481 2482 // The code after the try is the implicit successor. 2483 Succ = TrySuccessor; 2484 2485 // Save the current "try" context. 2486 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2487 TryTerminatedBlock = NewTryTerminatedBlock; 2488 2489 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2490 Block = NULL; 2491 Block = addStmt(Terminator->getTryBlock()); 2492 return Block; 2493} 2494 2495CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2496 // CXXCatchStmt are treated like labels, so they are the first statement in a 2497 // block. 2498 2499 // Save local scope position because in case of exception variable ScopePos 2500 // won't be restored when traversing AST. 2501 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2502 2503 // Create local scope for possible exception variable. 2504 // Store scope position. Add implicit destructor. 2505 if (VarDecl* VD = CS->getExceptionDecl()) { 2506 LocalScope::const_iterator BeginScopePos = ScopePos; 2507 addLocalScopeForVarDecl(VD); 2508 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2509 } 2510 2511 if (CS->getHandlerBlock()) 2512 addStmt(CS->getHandlerBlock()); 2513 2514 CFGBlock* CatchBlock = Block; 2515 if (!CatchBlock) 2516 CatchBlock = createBlock(); 2517 2518 CatchBlock->setLabel(CS); 2519 2520 if (badCFG) 2521 return 0; 2522 2523 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2524 Block = NULL; 2525 2526 return CatchBlock; 2527} 2528 2529CFGBlock* CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt* S) { 2530 // C++0x for-range statements are specified as [stmt.ranged]: 2531 // 2532 // { 2533 // auto && __range = range-init; 2534 // for ( auto __begin = begin-expr, 2535 // __end = end-expr; 2536 // __begin != __end; 2537 // ++__begin ) { 2538 // for-range-declaration = *__begin; 2539 // statement 2540 // } 2541 // } 2542 2543 // Save local scope position before the addition of the implicit variables. 2544 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2545 2546 // Create local scopes and destructors for range, begin and end variables. 2547 if (Stmt *Range = S->getRangeStmt()) 2548 addLocalScopeForStmt(Range); 2549 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2550 addLocalScopeForStmt(BeginEnd); 2551 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2552 2553 LocalScope::const_iterator ContinueScopePos = ScopePos; 2554 2555 // "for" is a control-flow statement. Thus we stop processing the current 2556 // block. 2557 CFGBlock* LoopSuccessor = NULL; 2558 if (Block) { 2559 if (badCFG) 2560 return 0; 2561 LoopSuccessor = Block; 2562 } else 2563 LoopSuccessor = Succ; 2564 2565 // Save the current value for the break targets. 2566 // All breaks should go to the code following the loop. 2567 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2568 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2569 2570 // The block for the __begin != __end expression. 2571 CFGBlock* ConditionBlock = createBlock(false); 2572 ConditionBlock->setTerminator(S); 2573 2574 // Now add the actual condition to the condition block. 2575 if (Expr *C = S->getCond()) { 2576 Block = ConditionBlock; 2577 CFGBlock *BeginConditionBlock = addStmt(C); 2578 if (badCFG) 2579 return 0; 2580 assert(BeginConditionBlock == ConditionBlock && 2581 "condition block in for-range was unexpectedly complex"); 2582 (void)BeginConditionBlock; 2583 } 2584 2585 // The condition block is the implicit successor for the loop body as well as 2586 // any code above the loop. 2587 Succ = ConditionBlock; 2588 2589 // See if this is a known constant. 2590 TryResult KnownVal(true); 2591 2592 if (S->getCond()) 2593 KnownVal = tryEvaluateBool(S->getCond()); 2594 2595 // Now create the loop body. 2596 { 2597 assert(S->getBody()); 2598 2599 // Save the current values for Block, Succ, and continue targets. 2600 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2601 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2602 2603 // Generate increment code in its own basic block. This is the target of 2604 // continue statements. 2605 Block = 0; 2606 Succ = addStmt(S->getInc()); 2607 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2608 2609 // The starting block for the loop increment is the block that should 2610 // represent the 'loop target' for looping back to the start of the loop. 2611 ContinueJumpTarget.block->setLoopTarget(S); 2612 2613 // Finish up the increment block and prepare to start the loop body. 2614 assert(Block); 2615 if (badCFG) 2616 return 0; 2617 Block = 0; 2618 2619 2620 // Add implicit scope and dtors for loop variable. 2621 addLocalScopeAndDtors(S->getLoopVarStmt()); 2622 2623 // Populate a new block to contain the loop body and loop variable. 2624 Block = addStmt(S->getBody()); 2625 if (badCFG) 2626 return 0; 2627 Block = addStmt(S->getLoopVarStmt()); 2628 if (badCFG) 2629 return 0; 2630 2631 // This new body block is a successor to our condition block. 2632 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2633 } 2634 2635 // Link up the condition block with the code that follows the loop (the 2636 // false branch). 2637 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2638 2639 // Add the initialization statements. 2640 Block = createBlock(); 2641 addStmt(S->getBeginEndStmt()); 2642 return addStmt(S->getRangeStmt()); 2643} 2644 2645CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2646 AddStmtChoice asc) { 2647 if (BuildOpts.AddImplicitDtors) { 2648 // If adding implicit destructors visit the full expression for adding 2649 // destructors of temporaries. 2650 VisitForTemporaryDtors(E->getSubExpr()); 2651 2652 // Full expression has to be added as CFGStmt so it will be sequenced 2653 // before destructors of it's temporaries. 2654 asc = asc.withAlwaysAdd(true); 2655 } 2656 return Visit(E->getSubExpr(), asc); 2657} 2658 2659CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2660 AddStmtChoice asc) { 2661 if (asc.alwaysAdd(*this, E)) { 2662 autoCreateBlock(); 2663 appendStmt(Block, E); 2664 2665 // We do not want to propagate the AlwaysAdd property. 2666 asc = asc.withAlwaysAdd(false); 2667 } 2668 return Visit(E->getSubExpr(), asc); 2669} 2670 2671CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2672 AddStmtChoice asc) { 2673 autoCreateBlock(); 2674 if (!C->isElidable()) 2675 appendStmt(Block, C); 2676 2677 return VisitChildren(C); 2678} 2679 2680CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2681 AddStmtChoice asc) { 2682 if (asc.alwaysAdd(*this, E)) { 2683 autoCreateBlock(); 2684 appendStmt(Block, E); 2685 // We do not want to propagate the AlwaysAdd property. 2686 asc = asc.withAlwaysAdd(false); 2687 } 2688 return Visit(E->getSubExpr(), asc); 2689} 2690 2691CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2692 AddStmtChoice asc) { 2693 autoCreateBlock(); 2694 appendStmt(Block, C); 2695 return VisitChildren(C); 2696} 2697 2698CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2699 AddStmtChoice asc) { 2700 if (asc.alwaysAdd(*this, E)) { 2701 autoCreateBlock(); 2702 appendStmt(Block, E); 2703 } 2704 return Visit(E->getSubExpr(), AddStmtChoice()); 2705} 2706 2707CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2708 // Lazily create the indirect-goto dispatch block if there isn't one already. 2709 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2710 2711 if (!IBlock) { 2712 IBlock = createBlock(false); 2713 cfg->setIndirectGotoBlock(IBlock); 2714 } 2715 2716 // IndirectGoto is a control-flow statement. Thus we stop processing the 2717 // current block and create a new one. 2718 if (badCFG) 2719 return 0; 2720 2721 Block = createBlock(false); 2722 Block->setTerminator(I); 2723 addSuccessor(Block, IBlock); 2724 return addStmt(I->getTarget()); 2725} 2726 2727CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2728tryAgain: 2729 if (!E) { 2730 badCFG = true; 2731 return NULL; 2732 } 2733 switch (E->getStmtClass()) { 2734 default: 2735 return VisitChildrenForTemporaryDtors(E); 2736 2737 case Stmt::BinaryOperatorClass: 2738 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2739 2740 case Stmt::CXXBindTemporaryExprClass: 2741 return VisitCXXBindTemporaryExprForTemporaryDtors( 2742 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2743 2744 case Stmt::BinaryConditionalOperatorClass: 2745 case Stmt::ConditionalOperatorClass: 2746 return VisitConditionalOperatorForTemporaryDtors( 2747 cast<AbstractConditionalOperator>(E), BindToTemporary); 2748 2749 case Stmt::ImplicitCastExprClass: 2750 // For implicit cast we want BindToTemporary to be passed further. 2751 E = cast<CastExpr>(E)->getSubExpr(); 2752 goto tryAgain; 2753 2754 case Stmt::ParenExprClass: 2755 E = cast<ParenExpr>(E)->getSubExpr(); 2756 goto tryAgain; 2757 } 2758} 2759 2760CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2761 // When visiting children for destructors we want to visit them in reverse 2762 // order. Because there's no reverse iterator for children must to reverse 2763 // them in helper vector. 2764 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2765 ChildrenVect ChildrenRev; 2766 for (Stmt::child_range I = E->children(); I; ++I) { 2767 if (*I) ChildrenRev.push_back(*I); 2768 } 2769 2770 CFGBlock *B = Block; 2771 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2772 L = ChildrenRev.rend(); I != L; ++I) { 2773 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2774 B = R; 2775 } 2776 return B; 2777} 2778 2779CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2780 if (E->isLogicalOp()) { 2781 // Destructors for temporaries in LHS expression should be called after 2782 // those for RHS expression. Even if this will unnecessarily create a block, 2783 // this block will be used at least by the full expression. 2784 autoCreateBlock(); 2785 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2786 if (badCFG) 2787 return NULL; 2788 2789 Succ = ConfluenceBlock; 2790 Block = NULL; 2791 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2792 2793 if (RHSBlock) { 2794 if (badCFG) 2795 return NULL; 2796 2797 // If RHS expression did produce destructors we need to connect created 2798 // blocks to CFG in same manner as for binary operator itself. 2799 CFGBlock *LHSBlock = createBlock(false); 2800 LHSBlock->setTerminator(CFGTerminator(E, true)); 2801 2802 // For binary operator LHS block is before RHS in list of predecessors 2803 // of ConfluenceBlock. 2804 std::reverse(ConfluenceBlock->pred_begin(), 2805 ConfluenceBlock->pred_end()); 2806 2807 // See if this is a known constant. 2808 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2809 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2810 KnownVal.negate(); 2811 2812 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2813 // itself. 2814 if (E->getOpcode() == BO_LOr) { 2815 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2816 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2817 } else { 2818 assert (E->getOpcode() == BO_LAnd); 2819 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2820 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2821 } 2822 2823 Block = LHSBlock; 2824 return LHSBlock; 2825 } 2826 2827 Block = ConfluenceBlock; 2828 return ConfluenceBlock; 2829 } 2830 2831 if (E->isAssignmentOp()) { 2832 // For assignment operator (=) LHS expression is visited 2833 // before RHS expression. For destructors visit them in reverse order. 2834 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2835 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2836 return LHSBlock ? LHSBlock : RHSBlock; 2837 } 2838 2839 // For any other binary operator RHS expression is visited before 2840 // LHS expression (order of children). For destructors visit them in reverse 2841 // order. 2842 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2843 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2844 return RHSBlock ? RHSBlock : LHSBlock; 2845} 2846 2847CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2848 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2849 // First add destructors for temporaries in subexpression. 2850 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2851 if (!BindToTemporary) { 2852 // If lifetime of temporary is not prolonged (by assigning to constant 2853 // reference) add destructor for it. 2854 autoCreateBlock(); 2855 appendTemporaryDtor(Block, E); 2856 B = Block; 2857 } 2858 return B; 2859} 2860 2861CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2862 AbstractConditionalOperator *E, bool BindToTemporary) { 2863 // First add destructors for condition expression. Even if this will 2864 // unnecessarily create a block, this block will be used at least by the full 2865 // expression. 2866 autoCreateBlock(); 2867 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2868 if (badCFG) 2869 return NULL; 2870 if (BinaryConditionalOperator *BCO 2871 = dyn_cast<BinaryConditionalOperator>(E)) { 2872 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2873 if (badCFG) 2874 return NULL; 2875 } 2876 2877 // Try to add block with destructors for LHS expression. 2878 CFGBlock *LHSBlock = NULL; 2879 Succ = ConfluenceBlock; 2880 Block = NULL; 2881 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2882 if (badCFG) 2883 return NULL; 2884 2885 // Try to add block with destructors for RHS expression; 2886 Succ = ConfluenceBlock; 2887 Block = NULL; 2888 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2889 BindToTemporary); 2890 if (badCFG) 2891 return NULL; 2892 2893 if (!RHSBlock && !LHSBlock) { 2894 // If neither LHS nor RHS expression had temporaries to destroy don't create 2895 // more blocks. 2896 Block = ConfluenceBlock; 2897 return Block; 2898 } 2899 2900 Block = createBlock(false); 2901 Block->setTerminator(CFGTerminator(E, true)); 2902 2903 // See if this is a known constant. 2904 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2905 2906 if (LHSBlock) { 2907 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2908 } else if (KnownVal.isFalse()) { 2909 addSuccessor(Block, NULL); 2910 } else { 2911 addSuccessor(Block, ConfluenceBlock); 2912 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2913 } 2914 2915 if (!RHSBlock) 2916 RHSBlock = ConfluenceBlock; 2917 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2918 2919 return Block; 2920} 2921 2922} // end anonymous namespace 2923 2924/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2925/// no successors or predecessors. If this is the first block created in the 2926/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2927CFGBlock* CFG::createBlock() { 2928 bool first_block = begin() == end(); 2929 2930 // Create the block. 2931 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2932 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2933 Blocks.push_back(Mem, BlkBVC); 2934 2935 // If this is the first block, set it as the Entry and Exit. 2936 if (first_block) 2937 Entry = Exit = &back(); 2938 2939 // Return the block. 2940 return &back(); 2941} 2942 2943/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2944/// CFG is returned to the caller. 2945CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2946 const BuildOptions &BO) { 2947 CFGBuilder Builder(C, BO); 2948 return Builder.buildCFG(D, Statement); 2949} 2950 2951const CXXDestructorDecl * 2952CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 2953 switch (getKind()) { 2954 case CFGElement::Invalid: 2955 case CFGElement::Statement: 2956 case CFGElement::Initializer: 2957 llvm_unreachable("getDestructorDecl should only be used with " 2958 "ImplicitDtors"); 2959 case CFGElement::AutomaticObjectDtor: { 2960 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 2961 QualType ty = var->getType(); 2962 ty = ty.getNonReferenceType(); 2963 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 2964 ty = arrayType->getElementType(); 2965 } 2966 const RecordType *recordType = ty->getAs<RecordType>(); 2967 const CXXRecordDecl *classDecl = 2968 cast<CXXRecordDecl>(recordType->getDecl()); 2969 return classDecl->getDestructor(); 2970 } 2971 case CFGElement::TemporaryDtor: { 2972 const CXXBindTemporaryExpr *bindExpr = 2973 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 2974 const CXXTemporary *temp = bindExpr->getTemporary(); 2975 return temp->getDestructor(); 2976 } 2977 case CFGElement::BaseDtor: 2978 case CFGElement::MemberDtor: 2979 2980 // Not yet supported. 2981 return 0; 2982 } 2983 llvm_unreachable("getKind() returned bogus value"); 2984 return 0; 2985} 2986 2987bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 2988 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 2989 QualType ty = cdecl->getType(); 2990 return cast<FunctionType>(ty)->getNoReturnAttr(); 2991 } 2992 return false; 2993} 2994 2995//===----------------------------------------------------------------------===// 2996// CFG: Queries for BlkExprs. 2997//===----------------------------------------------------------------------===// 2998 2999namespace { 3000 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3001} 3002 3003static void FindSubExprAssignments(Stmt *S, 3004 llvm::SmallPtrSet<Expr*,50>& Set) { 3005 if (!S) 3006 return; 3007 3008 for (Stmt::child_range I = S->children(); I; ++I) { 3009 Stmt *child = *I; 3010 if (!child) 3011 continue; 3012 3013 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3014 if (B->isAssignmentOp()) Set.insert(B); 3015 3016 FindSubExprAssignments(child, Set); 3017 } 3018} 3019 3020static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3021 BlkExprMapTy* M = new BlkExprMapTy(); 3022 3023 // Look for assignments that are used as subexpressions. These are the only 3024 // assignments that we want to *possibly* register as a block-level 3025 // expression. Basically, if an assignment occurs both in a subexpression and 3026 // at the block-level, it is a block-level expression. 3027 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 3028 3029 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3030 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3031 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3032 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3033 3034 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3035 3036 // Iterate over the statements again on identify the Expr* and Stmt* at the 3037 // block-level that are block-level expressions. 3038 3039 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3040 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3041 if (!CS) 3042 continue; 3043 if (Expr* Exp = dyn_cast<Expr>(CS->getStmt())) { 3044 3045 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3046 // Assignment expressions that are not nested within another 3047 // expression are really "statements" whose value is never used by 3048 // another expression. 3049 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3050 continue; 3051 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 3052 // Special handling for statement expressions. The last statement in 3053 // the statement expression is also a block-level expr. 3054 const CompoundStmt* C = Terminator->getSubStmt(); 3055 if (!C->body_empty()) { 3056 unsigned x = M->size(); 3057 (*M)[C->body_back()] = x; 3058 } 3059 } 3060 3061 unsigned x = M->size(); 3062 (*M)[Exp] = x; 3063 } 3064 } 3065 3066 // Look at terminators. The condition is a block-level expression. 3067 3068 Stmt* S = (*I)->getTerminatorCondition(); 3069 3070 if (S && M->find(S) == M->end()) { 3071 unsigned x = M->size(); 3072 (*M)[S] = x; 3073 } 3074 } 3075 3076 return M; 3077} 3078 3079CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 3080 assert(S != NULL); 3081 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3082 3083 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3084 BlkExprMapTy::iterator I = M->find(S); 3085 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3086} 3087 3088unsigned CFG::getNumBlkExprs() { 3089 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3090 return M->size(); 3091 3092 // We assume callers interested in the number of BlkExprs will want 3093 // the map constructed if it doesn't already exist. 3094 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3095 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3096} 3097 3098//===----------------------------------------------------------------------===// 3099// Filtered walking of the CFG. 3100//===----------------------------------------------------------------------===// 3101 3102bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3103 const CFGBlock *From, const CFGBlock *To) { 3104 3105 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3106 // If the 'To' has no label or is labeled but the label isn't a 3107 // CaseStmt then filter this edge. 3108 if (const SwitchStmt *S = 3109 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3110 if (S->isAllEnumCasesCovered()) { 3111 const Stmt *L = To->getLabel(); 3112 if (!L || !isa<CaseStmt>(L)) 3113 return true; 3114 } 3115 } 3116 } 3117 3118 return false; 3119} 3120 3121//===----------------------------------------------------------------------===// 3122// Cleanup: CFG dstor. 3123//===----------------------------------------------------------------------===// 3124 3125CFG::~CFG() { 3126 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3127} 3128 3129//===----------------------------------------------------------------------===// 3130// CFG pretty printing 3131//===----------------------------------------------------------------------===// 3132 3133namespace { 3134 3135class StmtPrinterHelper : public PrinterHelper { 3136 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3137 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3138 StmtMapTy StmtMap; 3139 DeclMapTy DeclMap; 3140 signed currentBlock; 3141 unsigned currentStmt; 3142 const LangOptions &LangOpts; 3143public: 3144 3145 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3146 : currentBlock(0), currentStmt(0), LangOpts(LO) 3147 { 3148 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3149 unsigned j = 1; 3150 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3151 BI != BEnd; ++BI, ++j ) { 3152 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3153 const Stmt *stmt= SE->getStmt(); 3154 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3155 StmtMap[stmt] = P; 3156 3157 switch (stmt->getStmtClass()) { 3158 case Stmt::DeclStmtClass: 3159 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3160 break; 3161 case Stmt::IfStmtClass: { 3162 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3163 if (var) 3164 DeclMap[var] = P; 3165 break; 3166 } 3167 case Stmt::ForStmtClass: { 3168 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3169 if (var) 3170 DeclMap[var] = P; 3171 break; 3172 } 3173 case Stmt::WhileStmtClass: { 3174 const VarDecl *var = 3175 cast<WhileStmt>(stmt)->getConditionVariable(); 3176 if (var) 3177 DeclMap[var] = P; 3178 break; 3179 } 3180 case Stmt::SwitchStmtClass: { 3181 const VarDecl *var = 3182 cast<SwitchStmt>(stmt)->getConditionVariable(); 3183 if (var) 3184 DeclMap[var] = P; 3185 break; 3186 } 3187 case Stmt::CXXCatchStmtClass: { 3188 const VarDecl *var = 3189 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3190 if (var) 3191 DeclMap[var] = P; 3192 break; 3193 } 3194 default: 3195 break; 3196 } 3197 } 3198 } 3199 } 3200 } 3201 3202 3203 virtual ~StmtPrinterHelper() {} 3204 3205 const LangOptions &getLangOpts() const { return LangOpts; } 3206 void setBlockID(signed i) { currentBlock = i; } 3207 void setStmtID(unsigned i) { currentStmt = i; } 3208 3209 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 3210 StmtMapTy::iterator I = StmtMap.find(S); 3211 3212 if (I == StmtMap.end()) 3213 return false; 3214 3215 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3216 && I->second.second == currentStmt) { 3217 return false; 3218 } 3219 3220 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3221 return true; 3222 } 3223 3224 bool handleDecl(const Decl* D, llvm::raw_ostream& OS) { 3225 DeclMapTy::iterator I = DeclMap.find(D); 3226 3227 if (I == DeclMap.end()) 3228 return false; 3229 3230 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3231 && I->second.second == currentStmt) { 3232 return false; 3233 } 3234 3235 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3236 return true; 3237 } 3238}; 3239} // end anonymous namespace 3240 3241 3242namespace { 3243class CFGBlockTerminatorPrint 3244 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3245 3246 llvm::raw_ostream& OS; 3247 StmtPrinterHelper* Helper; 3248 PrintingPolicy Policy; 3249public: 3250 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 3251 const PrintingPolicy &Policy) 3252 : OS(os), Helper(helper), Policy(Policy) {} 3253 3254 void VisitIfStmt(IfStmt* I) { 3255 OS << "if "; 3256 I->getCond()->printPretty(OS,Helper,Policy); 3257 } 3258 3259 // Default case. 3260 void VisitStmt(Stmt* Terminator) { 3261 Terminator->printPretty(OS, Helper, Policy); 3262 } 3263 3264 void VisitForStmt(ForStmt* F) { 3265 OS << "for (" ; 3266 if (F->getInit()) 3267 OS << "..."; 3268 OS << "; "; 3269 if (Stmt* C = F->getCond()) 3270 C->printPretty(OS, Helper, Policy); 3271 OS << "; "; 3272 if (F->getInc()) 3273 OS << "..."; 3274 OS << ")"; 3275 } 3276 3277 void VisitWhileStmt(WhileStmt* W) { 3278 OS << "while " ; 3279 if (Stmt* C = W->getCond()) 3280 C->printPretty(OS, Helper, Policy); 3281 } 3282 3283 void VisitDoStmt(DoStmt* D) { 3284 OS << "do ... while "; 3285 if (Stmt* C = D->getCond()) 3286 C->printPretty(OS, Helper, Policy); 3287 } 3288 3289 void VisitSwitchStmt(SwitchStmt* Terminator) { 3290 OS << "switch "; 3291 Terminator->getCond()->printPretty(OS, Helper, Policy); 3292 } 3293 3294 void VisitCXXTryStmt(CXXTryStmt* CS) { 3295 OS << "try ..."; 3296 } 3297 3298 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3299 C->getCond()->printPretty(OS, Helper, Policy); 3300 OS << " ? ... : ..."; 3301 } 3302 3303 void VisitChooseExpr(ChooseExpr* C) { 3304 OS << "__builtin_choose_expr( "; 3305 C->getCond()->printPretty(OS, Helper, Policy); 3306 OS << " )"; 3307 } 3308 3309 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 3310 OS << "goto *"; 3311 I->getTarget()->printPretty(OS, Helper, Policy); 3312 } 3313 3314 void VisitBinaryOperator(BinaryOperator* B) { 3315 if (!B->isLogicalOp()) { 3316 VisitExpr(B); 3317 return; 3318 } 3319 3320 B->getLHS()->printPretty(OS, Helper, Policy); 3321 3322 switch (B->getOpcode()) { 3323 case BO_LOr: 3324 OS << " || ..."; 3325 return; 3326 case BO_LAnd: 3327 OS << " && ..."; 3328 return; 3329 default: 3330 assert(false && "Invalid logical operator."); 3331 } 3332 } 3333 3334 void VisitExpr(Expr* E) { 3335 E->printPretty(OS, Helper, Policy); 3336 } 3337}; 3338} // end anonymous namespace 3339 3340static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3341 const CFGElement &E) { 3342 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3343 Stmt *S = CS->getStmt(); 3344 3345 if (Helper) { 3346 3347 // special printing for statement-expressions. 3348 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3349 CompoundStmt* Sub = SE->getSubStmt(); 3350 3351 if (Sub->children()) { 3352 OS << "({ ... ; "; 3353 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3354 OS << " })\n"; 3355 return; 3356 } 3357 } 3358 // special printing for comma expressions. 3359 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3360 if (B->getOpcode() == BO_Comma) { 3361 OS << "... , "; 3362 Helper->handledStmt(B->getRHS(),OS); 3363 OS << '\n'; 3364 return; 3365 } 3366 } 3367 } 3368 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3369 3370 if (isa<CXXOperatorCallExpr>(S)) { 3371 OS << " (OperatorCall)"; 3372 } else if (isa<CXXBindTemporaryExpr>(S)) { 3373 OS << " (BindTemporary)"; 3374 } 3375 3376 // Expressions need a newline. 3377 if (isa<Expr>(S)) 3378 OS << '\n'; 3379 3380 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3381 const CXXCtorInitializer *I = IE->getInitializer(); 3382 if (I->isBaseInitializer()) 3383 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3384 else OS << I->getAnyMember()->getName(); 3385 3386 OS << "("; 3387 if (Expr* IE = I->getInit()) 3388 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3389 OS << ")"; 3390 3391 if (I->isBaseInitializer()) 3392 OS << " (Base initializer)\n"; 3393 else OS << " (Member initializer)\n"; 3394 3395 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3396 const VarDecl* VD = DE->getVarDecl(); 3397 Helper->handleDecl(VD, OS); 3398 3399 const Type* T = VD->getType().getTypePtr(); 3400 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3401 T = RT->getPointeeType().getTypePtr(); 3402 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3403 T = ET; 3404 3405 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3406 OS << " (Implicit destructor)\n"; 3407 3408 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3409 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3410 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3411 OS << " (Base object destructor)\n"; 3412 3413 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3414 const FieldDecl *FD = ME->getFieldDecl(); 3415 3416 const Type *T = FD->getType().getTypePtr(); 3417 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3418 T = ET; 3419 3420 OS << "this->" << FD->getName(); 3421 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3422 OS << " (Member object destructor)\n"; 3423 3424 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3425 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3426 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3427 OS << " (Temporary object destructor)\n"; 3428 } 3429} 3430 3431static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3432 const CFGBlock& B, 3433 StmtPrinterHelper* Helper, bool print_edges) { 3434 3435 if (Helper) Helper->setBlockID(B.getBlockID()); 3436 3437 // Print the header. 3438 OS << "\n [ B" << B.getBlockID(); 3439 3440 if (&B == &cfg->getEntry()) 3441 OS << " (ENTRY) ]\n"; 3442 else if (&B == &cfg->getExit()) 3443 OS << " (EXIT) ]\n"; 3444 else if (&B == cfg->getIndirectGotoBlock()) 3445 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3446 else 3447 OS << " ]\n"; 3448 3449 // Print the label of this block. 3450 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3451 3452 if (print_edges) 3453 OS << " "; 3454 3455 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3456 OS << L->getName(); 3457 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3458 OS << "case "; 3459 C->getLHS()->printPretty(OS, Helper, 3460 PrintingPolicy(Helper->getLangOpts())); 3461 if (C->getRHS()) { 3462 OS << " ... "; 3463 C->getRHS()->printPretty(OS, Helper, 3464 PrintingPolicy(Helper->getLangOpts())); 3465 } 3466 } else if (isa<DefaultStmt>(Label)) 3467 OS << "default"; 3468 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3469 OS << "catch ("; 3470 if (CS->getExceptionDecl()) 3471 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3472 0); 3473 else 3474 OS << "..."; 3475 OS << ")"; 3476 3477 } else 3478 assert(false && "Invalid label statement in CFGBlock."); 3479 3480 OS << ":\n"; 3481 } 3482 3483 // Iterate through the statements in the block and print them. 3484 unsigned j = 1; 3485 3486 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3487 I != E ; ++I, ++j ) { 3488 3489 // Print the statement # in the basic block and the statement itself. 3490 if (print_edges) 3491 OS << " "; 3492 3493 OS << llvm::format("%3d", j) << ": "; 3494 3495 if (Helper) 3496 Helper->setStmtID(j); 3497 3498 print_elem(OS,Helper,*I); 3499 } 3500 3501 // Print the terminator of this block. 3502 if (B.getTerminator()) { 3503 if (print_edges) 3504 OS << " "; 3505 3506 OS << " T: "; 3507 3508 if (Helper) Helper->setBlockID(-1); 3509 3510 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3511 PrintingPolicy(Helper->getLangOpts())); 3512 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3513 OS << '\n'; 3514 } 3515 3516 if (print_edges) { 3517 // Print the predecessors of this block. 3518 OS << " Predecessors (" << B.pred_size() << "):"; 3519 unsigned i = 0; 3520 3521 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3522 I != E; ++I, ++i) { 3523 3524 if (i == 8 || (i-8) == 0) 3525 OS << "\n "; 3526 3527 OS << " B" << (*I)->getBlockID(); 3528 } 3529 3530 OS << '\n'; 3531 3532 // Print the successors of this block. 3533 OS << " Successors (" << B.succ_size() << "):"; 3534 i = 0; 3535 3536 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3537 I != E; ++I, ++i) { 3538 3539 if (i == 8 || (i-8) % 10 == 0) 3540 OS << "\n "; 3541 3542 if (*I) 3543 OS << " B" << (*I)->getBlockID(); 3544 else 3545 OS << " NULL"; 3546 } 3547 3548 OS << '\n'; 3549 } 3550} 3551 3552 3553/// dump - A simple pretty printer of a CFG that outputs to stderr. 3554void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3555 3556/// print - A simple pretty printer of a CFG that outputs to an ostream. 3557void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3558 StmtPrinterHelper Helper(this, LO); 3559 3560 // Print the entry block. 3561 print_block(OS, this, getEntry(), &Helper, true); 3562 3563 // Iterate through the CFGBlocks and print them one by one. 3564 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3565 // Skip the entry block, because we already printed it. 3566 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3567 continue; 3568 3569 print_block(OS, this, **I, &Helper, true); 3570 } 3571 3572 // Print the exit block. 3573 print_block(OS, this, getExit(), &Helper, true); 3574 OS.flush(); 3575} 3576 3577/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3578void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3579 print(llvm::errs(), cfg, LO); 3580} 3581 3582/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3583/// Generally this will only be called from CFG::print. 3584void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3585 const LangOptions &LO) const { 3586 StmtPrinterHelper Helper(cfg, LO); 3587 print_block(OS, cfg, *this, &Helper, true); 3588} 3589 3590/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3591void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3592 const LangOptions &LO) const { 3593 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3594 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3595} 3596 3597Stmt* CFGBlock::getTerminatorCondition() { 3598 Stmt *Terminator = this->Terminator; 3599 if (!Terminator) 3600 return NULL; 3601 3602 Expr* E = NULL; 3603 3604 switch (Terminator->getStmtClass()) { 3605 default: 3606 break; 3607 3608 case Stmt::ForStmtClass: 3609 E = cast<ForStmt>(Terminator)->getCond(); 3610 break; 3611 3612 case Stmt::WhileStmtClass: 3613 E = cast<WhileStmt>(Terminator)->getCond(); 3614 break; 3615 3616 case Stmt::DoStmtClass: 3617 E = cast<DoStmt>(Terminator)->getCond(); 3618 break; 3619 3620 case Stmt::IfStmtClass: 3621 E = cast<IfStmt>(Terminator)->getCond(); 3622 break; 3623 3624 case Stmt::ChooseExprClass: 3625 E = cast<ChooseExpr>(Terminator)->getCond(); 3626 break; 3627 3628 case Stmt::IndirectGotoStmtClass: 3629 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3630 break; 3631 3632 case Stmt::SwitchStmtClass: 3633 E = cast<SwitchStmt>(Terminator)->getCond(); 3634 break; 3635 3636 case Stmt::BinaryConditionalOperatorClass: 3637 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3638 break; 3639 3640 case Stmt::ConditionalOperatorClass: 3641 E = cast<ConditionalOperator>(Terminator)->getCond(); 3642 break; 3643 3644 case Stmt::BinaryOperatorClass: // '&&' and '||' 3645 E = cast<BinaryOperator>(Terminator)->getLHS(); 3646 break; 3647 3648 case Stmt::ObjCForCollectionStmtClass: 3649 return Terminator; 3650 } 3651 3652 return E ? E->IgnoreParens() : NULL; 3653} 3654 3655//===----------------------------------------------------------------------===// 3656// CFG Graphviz Visualization 3657//===----------------------------------------------------------------------===// 3658 3659 3660#ifndef NDEBUG 3661static StmtPrinterHelper* GraphHelper; 3662#endif 3663 3664void CFG::viewCFG(const LangOptions &LO) const { 3665#ifndef NDEBUG 3666 StmtPrinterHelper H(this, LO); 3667 GraphHelper = &H; 3668 llvm::ViewGraph(this,"CFG"); 3669 GraphHelper = NULL; 3670#endif 3671} 3672 3673namespace llvm { 3674template<> 3675struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3676 3677 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3678 3679 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3680 3681#ifndef NDEBUG 3682 std::string OutSStr; 3683 llvm::raw_string_ostream Out(OutSStr); 3684 print_block(Out,Graph, *Node, GraphHelper, false); 3685 std::string& OutStr = Out.str(); 3686 3687 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3688 3689 // Process string output to make it nicer... 3690 for (unsigned i = 0; i != OutStr.length(); ++i) 3691 if (OutStr[i] == '\n') { // Left justify 3692 OutStr[i] = '\\'; 3693 OutStr.insert(OutStr.begin()+i+1, 'l'); 3694 } 3695 3696 return OutStr; 3697#else 3698 return ""; 3699#endif 3700 } 3701}; 3702} // end namespace llvm 3703