CFG.cpp revision 26517e4ffe7c2c366496feb02370ba24ab5ae8f5
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 *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 324 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 325 CFGBlock *VisitCaseStmt(CaseStmt *C); 326 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 327 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 328 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 329 AddStmtChoice asc); 330 CFGBlock *VisitContinueStmt(ContinueStmt *C); 331 CFGBlock *VisitDeclStmt(DeclStmt *DS); 332 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 333 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 334 CFGBlock *VisitDoStmt(DoStmt *D); 335 CFGBlock *VisitForStmt(ForStmt *F); 336 CFGBlock *VisitGotoStmt(GotoStmt* G); 337 CFGBlock *VisitIfStmt(IfStmt *I); 338 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 339 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 340 CFGBlock *VisitLabelStmt(LabelStmt *L); 341 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 342 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 343 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 344 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 345 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 346 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 347 CFGBlock *VisitReturnStmt(ReturnStmt* R); 348 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 349 AddStmtChoice asc); 350 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 351 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 352 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 353 CFGBlock *VisitWhileStmt(WhileStmt *W); 354 355 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 356 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 357 CFGBlock *VisitChildren(Stmt* S); 358 359 // Visitors to walk an AST and generate destructors of temporaries in 360 // full expression. 361 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 362 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 363 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 364 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 365 bool BindToTemporary); 366 CFGBlock * 367 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 368 bool BindToTemporary); 369 370 // NYS == Not Yet Supported 371 CFGBlock* NYS() { 372 badCFG = true; 373 return Block; 374 } 375 376 void autoCreateBlock() { if (!Block) Block = createBlock(); } 377 CFGBlock *createBlock(bool add_successor = true); 378 379 CFGBlock *addStmt(Stmt *S) { 380 return Visit(S, AddStmtChoice::AlwaysAdd); 381 } 382 CFGBlock *addInitializer(CXXCtorInitializer *I); 383 void addAutomaticObjDtors(LocalScope::const_iterator B, 384 LocalScope::const_iterator E, Stmt* S); 385 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 386 387 // Local scopes creation. 388 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 389 390 void addLocalScopeForStmt(Stmt* S); 391 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 392 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 393 394 void addLocalScopeAndDtors(Stmt* S); 395 396 // Interface to CFGBlock - adding CFGElements. 397 void appendStmt(CFGBlock *B, const Stmt *S) { 398 if (alwaysAdd(S)) 399 cachedEntry->second = B; 400 401 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 402 } 403 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 404 B->appendInitializer(I, cfg->getBumpVectorContext()); 405 } 406 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 407 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 408 } 409 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 410 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 411 } 412 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 413 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 414 } 415 416 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 417 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 418 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 419 LocalScope::const_iterator E, Stmt* S); 420 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 421 LocalScope::const_iterator B, LocalScope::const_iterator E); 422 423 void addSuccessor(CFGBlock *B, CFGBlock *S) { 424 B->addSuccessor(S, cfg->getBumpVectorContext()); 425 } 426 427 /// Try and evaluate an expression to an integer constant. 428 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 429 if (!BuildOpts.PruneTriviallyFalseEdges) 430 return false; 431 return !S->isTypeDependent() && 432 !S->isValueDependent() && 433 S->Evaluate(outResult, *Context); 434 } 435 436 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 437 /// if we can evaluate to a known value, otherwise return -1. 438 TryResult tryEvaluateBool(Expr *S) { 439 Expr::EvalResult Result; 440 if (!tryEvaluate(S, Result)) 441 return TryResult(); 442 443 if (Result.Val.isInt()) 444 return Result.Val.getInt().getBoolValue(); 445 446 if (Result.Val.isLValue()) { 447 Expr *e = Result.Val.getLValueBase(); 448 const CharUnits &c = Result.Val.getLValueOffset(); 449 if (!e && c.isZero()) 450 return false; 451 } 452 return TryResult(); 453 } 454 455}; 456 457inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 458 const Stmt *stmt) const { 459 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 460} 461 462bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 463 if (!BuildOpts.forcedBlkExprs) 464 return false; 465 466 if (lastLookup == stmt) { 467 if (cachedEntry) { 468 assert(cachedEntry->first == stmt); 469 return true; 470 } 471 return false; 472 } 473 474 lastLookup = stmt; 475 476 // Perform the lookup! 477 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 478 479 if (!fb) { 480 // No need to update 'cachedEntry', since it will always be null. 481 assert(cachedEntry == 0); 482 return false; 483 } 484 485 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 486 if (itr == fb->end()) { 487 cachedEntry = 0; 488 return false; 489 } 490 491 cachedEntry = &*itr; 492 return true; 493} 494 495// FIXME: Add support for dependent-sized array types in C++? 496// Does it even make sense to build a CFG for an uninstantiated template? 497static const VariableArrayType *FindVA(const Type *t) { 498 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 499 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 500 if (vat->getSizeExpr()) 501 return vat; 502 503 t = vt->getElementType().getTypePtr(); 504 } 505 506 return 0; 507} 508 509/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 510/// arbitrary statement. Examples include a single expression or a function 511/// body (compound statement). The ownership of the returned CFG is 512/// transferred to the caller. If CFG construction fails, this method returns 513/// NULL. 514CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement) { 515 assert(cfg.get()); 516 if (!Statement) 517 return NULL; 518 519 // Create an empty block that will serve as the exit block for the CFG. Since 520 // this is the first block added to the CFG, it will be implicitly registered 521 // as the exit block. 522 Succ = createBlock(); 523 assert(Succ == &cfg->getExit()); 524 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 525 526 if (BuildOpts.AddImplicitDtors) 527 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 528 addImplicitDtorsForDestructor(DD); 529 530 // Visit the statements and create the CFG. 531 CFGBlock *B = addStmt(Statement); 532 533 if (badCFG) 534 return NULL; 535 536 // For C++ constructor add initializers to CFG. 537 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 538 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 539 E = CD->init_rend(); I != E; ++I) { 540 B = addInitializer(*I); 541 if (badCFG) 542 return NULL; 543 } 544 } 545 546 if (B) 547 Succ = B; 548 549 // Backpatch the gotos whose label -> block mappings we didn't know when we 550 // encountered them. 551 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 552 E = BackpatchBlocks.end(); I != E; ++I ) { 553 554 CFGBlock* B = I->block; 555 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 556 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 557 558 // If there is no target for the goto, then we are looking at an 559 // incomplete AST. Handle this by not registering a successor. 560 if (LI == LabelMap.end()) continue; 561 562 JumpTarget JT = LI->second; 563 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 564 JT.scopePosition); 565 addSuccessor(B, JT.block); 566 } 567 568 // Add successors to the Indirect Goto Dispatch block (if we have one). 569 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 570 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 571 E = AddressTakenLabels.end(); I != E; ++I ) { 572 573 // Lookup the target block. 574 LabelMapTy::iterator LI = LabelMap.find(*I); 575 576 // If there is no target block that contains label, then we are looking 577 // at an incomplete AST. Handle this by not registering a successor. 578 if (LI == LabelMap.end()) continue; 579 580 addSuccessor(B, LI->second.block); 581 } 582 583 // Create an empty entry block that has no predecessors. 584 cfg->setEntry(createBlock()); 585 586 return cfg.take(); 587} 588 589/// createBlock - Used to lazily create blocks that are connected 590/// to the current (global) succcessor. 591CFGBlock* CFGBuilder::createBlock(bool add_successor) { 592 CFGBlock* B = cfg->createBlock(); 593 if (add_successor && Succ) 594 addSuccessor(B, Succ); 595 return B; 596} 597 598/// addInitializer - Add C++ base or member initializer element to CFG. 599CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 600 if (!BuildOpts.AddInitializers) 601 return Block; 602 603 bool IsReference = false; 604 bool HasTemporaries = false; 605 606 // Destructors of temporaries in initialization expression should be called 607 // after initialization finishes. 608 Expr *Init = I->getInit(); 609 if (Init) { 610 if (FieldDecl *FD = I->getAnyMember()) 611 IsReference = FD->getType()->isReferenceType(); 612 HasTemporaries = isa<ExprWithCleanups>(Init); 613 614 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 615 // Generate destructors for temporaries in initialization expression. 616 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 617 IsReference); 618 } 619 } 620 621 autoCreateBlock(); 622 appendInitializer(Block, I); 623 624 if (Init) { 625 if (HasTemporaries) { 626 // For expression with temporaries go directly to subexpression to omit 627 // generating destructors for the second time. 628 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 629 } 630 return Visit(Init); 631 } 632 633 return Block; 634} 635 636/// addAutomaticObjDtors - Add to current block automatic objects destructors 637/// for objects in range of local scope positions. Use S as trigger statement 638/// for destructors. 639void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 640 LocalScope::const_iterator E, Stmt* S) { 641 if (!BuildOpts.AddImplicitDtors) 642 return; 643 644 if (B == E) 645 return; 646 647 autoCreateBlock(); 648 appendAutomaticObjDtors(Block, B, E, S); 649} 650 651/// addImplicitDtorsForDestructor - Add implicit destructors generated for 652/// base and member objects in destructor. 653void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 654 assert (BuildOpts.AddImplicitDtors 655 && "Can be called only when dtors should be added"); 656 const CXXRecordDecl *RD = DD->getParent(); 657 658 // At the end destroy virtual base objects. 659 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 660 VE = RD->vbases_end(); VI != VE; ++VI) { 661 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 662 if (!CD->hasTrivialDestructor()) { 663 autoCreateBlock(); 664 appendBaseDtor(Block, VI); 665 } 666 } 667 668 // Before virtual bases destroy direct base objects. 669 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 670 BE = RD->bases_end(); BI != BE; ++BI) { 671 if (!BI->isVirtual()) { 672 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 673 if (!CD->hasTrivialDestructor()) { 674 autoCreateBlock(); 675 appendBaseDtor(Block, BI); 676 } 677 } 678 } 679 680 // First destroy member objects. 681 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 682 FE = RD->field_end(); FI != FE; ++FI) { 683 // Check for constant size array. Set type to array element type. 684 QualType QT = FI->getType(); 685 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 686 if (AT->getSize() == 0) 687 continue; 688 QT = AT->getElementType(); 689 } 690 691 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 692 if (!CD->hasTrivialDestructor()) { 693 autoCreateBlock(); 694 appendMemberDtor(Block, *FI); 695 } 696 } 697} 698 699/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 700/// way return valid LocalScope object. 701LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 702 if (!Scope) { 703 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 704 Scope = alloc.Allocate<LocalScope>(); 705 BumpVectorContext ctx(alloc); 706 new (Scope) LocalScope(ctx, ScopePos); 707 } 708 return Scope; 709} 710 711/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 712/// that should create implicit scope (e.g. if/else substatements). 713void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 714 if (!BuildOpts.AddImplicitDtors) 715 return; 716 717 LocalScope *Scope = 0; 718 719 // For compound statement we will be creating explicit scope. 720 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 721 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 722 ; BI != BE; ++BI) { 723 Stmt *SI = *BI; 724 if (LabelStmt *LS = dyn_cast<LabelStmt>(SI)) 725 SI = LS->getSubStmt(); 726 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 727 Scope = addLocalScopeForDeclStmt(DS, Scope); 728 } 729 return; 730 } 731 732 // For any other statement scope will be implicit and as such will be 733 // interesting only for DeclStmt. 734 if (LabelStmt *LS = dyn_cast<LabelStmt>(S)) 735 S = LS->getSubStmt(); 736 if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) 737 addLocalScopeForDeclStmt(DS); 738} 739 740/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 741/// reuse Scope if not NULL. 742LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 743 LocalScope* Scope) { 744 if (!BuildOpts.AddImplicitDtors) 745 return Scope; 746 747 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 748 ; DI != DE; ++DI) { 749 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 750 Scope = addLocalScopeForVarDecl(VD, Scope); 751 } 752 return Scope; 753} 754 755/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 756/// create add scope for automatic objects and temporary objects bound to 757/// const reference. Will reuse Scope if not NULL. 758LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 759 LocalScope* Scope) { 760 if (!BuildOpts.AddImplicitDtors) 761 return Scope; 762 763 // Check if variable is local. 764 switch (VD->getStorageClass()) { 765 case SC_None: 766 case SC_Auto: 767 case SC_Register: 768 break; 769 default: return Scope; 770 } 771 772 // Check for const references bound to temporary. Set type to pointee. 773 QualType QT = VD->getType(); 774 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 775 QT = RT->getPointeeType(); 776 if (!QT.isConstQualified()) 777 return Scope; 778 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 779 return Scope; 780 } 781 782 // Check for constant size array. Set type to array element type. 783 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 784 if (AT->getSize() == 0) 785 return Scope; 786 QT = AT->getElementType(); 787 } 788 789 // Check if type is a C++ class with non-trivial destructor. 790 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 791 if (!CD->hasTrivialDestructor()) { 792 // Add the variable to scope 793 Scope = createOrReuseLocalScope(Scope); 794 Scope->addVar(VD); 795 ScopePos = Scope->begin(); 796 } 797 return Scope; 798} 799 800/// addLocalScopeAndDtors - For given statement add local scope for it and 801/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 802void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 803 if (!BuildOpts.AddImplicitDtors) 804 return; 805 806 LocalScope::const_iterator scopeBeginPos = ScopePos; 807 addLocalScopeForStmt(S); 808 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 809} 810 811/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 812/// automatic storage duration to CFGBlock's elements vector. Insertion will be 813/// performed in place specified with iterator. 814void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 815 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 816 BumpVectorContext& C = cfg->getBumpVectorContext(); 817 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 818 while (B != E) 819 I = Blk->insertAutomaticObjDtor(I, *B++, S); 820} 821 822/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 823/// automatic storage duration to CFGBlock's elements vector. Elements will be 824/// appended to physical end of the vector which happens to be logical 825/// beginning. 826void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 827 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 828 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 829} 830 831/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 832/// variables with automatic storage duration to CFGBlock's elements vector. 833/// Elements will be prepended to physical beginning of the vector which 834/// happens to be logical end. Use blocks terminator as statement that specifies 835/// destructors call site. 836void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 837 LocalScope::const_iterator B, LocalScope::const_iterator E) { 838 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 839} 840 841/// Visit - Walk the subtree of a statement and add extra 842/// blocks for ternary operators, &&, and ||. We also process "," and 843/// DeclStmts (which may contain nested control-flow). 844CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 845tryAgain: 846 if (!S) { 847 badCFG = true; 848 return 0; 849 } 850 switch (S->getStmtClass()) { 851 default: 852 return VisitStmt(S, asc); 853 854 case Stmt::AddrLabelExprClass: 855 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 856 857 case Stmt::BinaryConditionalOperatorClass: 858 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 859 860 case Stmt::BinaryOperatorClass: 861 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 862 863 case Stmt::BlockExprClass: 864 return VisitBlockExpr(cast<BlockExpr>(S), asc); 865 866 case Stmt::BreakStmtClass: 867 return VisitBreakStmt(cast<BreakStmt>(S)); 868 869 case Stmt::CallExprClass: 870 case Stmt::CXXOperatorCallExprClass: 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::CXXMemberCallExprClass: 907 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 908 909 case Stmt::CXXThrowExprClass: 910 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 911 912 case Stmt::CXXTryStmtClass: 913 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 914 915 case Stmt::CXXForRangeStmtClass: 916 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 917 918 case Stmt::DeclStmtClass: 919 return VisitDeclStmt(cast<DeclStmt>(S)); 920 921 case Stmt::DefaultStmtClass: 922 return VisitDefaultStmt(cast<DefaultStmt>(S)); 923 924 case Stmt::DoStmtClass: 925 return VisitDoStmt(cast<DoStmt>(S)); 926 927 case Stmt::ForStmtClass: 928 return VisitForStmt(cast<ForStmt>(S)); 929 930 case Stmt::GotoStmtClass: 931 return VisitGotoStmt(cast<GotoStmt>(S)); 932 933 case Stmt::IfStmtClass: 934 return VisitIfStmt(cast<IfStmt>(S)); 935 936 case Stmt::ImplicitCastExprClass: 937 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 938 939 case Stmt::IndirectGotoStmtClass: 940 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 941 942 case Stmt::LabelStmtClass: 943 return VisitLabelStmt(cast<LabelStmt>(S)); 944 945 case Stmt::MemberExprClass: 946 return VisitMemberExpr(cast<MemberExpr>(S), asc); 947 948 case Stmt::ObjCAtCatchStmtClass: 949 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 950 951 case Stmt::ObjCAtSynchronizedStmtClass: 952 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 953 954 case Stmt::ObjCAtThrowStmtClass: 955 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 956 957 case Stmt::ObjCAtTryStmtClass: 958 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 959 960 case Stmt::ObjCForCollectionStmtClass: 961 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 962 963 case Stmt::ParenExprClass: 964 S = cast<ParenExpr>(S)->getSubExpr(); 965 goto tryAgain; 966 967 case Stmt::NullStmtClass: 968 return Block; 969 970 case Stmt::ReturnStmtClass: 971 return VisitReturnStmt(cast<ReturnStmt>(S)); 972 973 case Stmt::UnaryExprOrTypeTraitExprClass: 974 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 975 asc); 976 977 case Stmt::StmtExprClass: 978 return VisitStmtExpr(cast<StmtExpr>(S), asc); 979 980 case Stmt::SwitchStmtClass: 981 return VisitSwitchStmt(cast<SwitchStmt>(S)); 982 983 case Stmt::UnaryOperatorClass: 984 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 985 986 case Stmt::WhileStmtClass: 987 return VisitWhileStmt(cast<WhileStmt>(S)); 988 } 989} 990 991CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 992 if (asc.alwaysAdd(*this, S)) { 993 autoCreateBlock(); 994 appendStmt(Block, S); 995 } 996 997 return VisitChildren(S); 998} 999 1000/// VisitChildren - Visit the children of a Stmt. 1001CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 1002 CFGBlock *lastBlock = Block; 1003 for (Stmt::child_range I = Terminator->children(); I; ++I) 1004 if (Stmt *child = *I) 1005 if (CFGBlock *b = Visit(child)) 1006 lastBlock = b; 1007 1008 return lastBlock; 1009} 1010 1011CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1012 AddStmtChoice asc) { 1013 AddressTakenLabels.insert(A->getLabel()); 1014 1015 if (asc.alwaysAdd(*this, A)) { 1016 autoCreateBlock(); 1017 appendStmt(Block, A); 1018 } 1019 1020 return Block; 1021} 1022 1023CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1024 AddStmtChoice asc) { 1025 if (asc.alwaysAdd(*this, U)) { 1026 autoCreateBlock(); 1027 appendStmt(Block, U); 1028 } 1029 1030 return Visit(U->getSubExpr(), AddStmtChoice()); 1031} 1032 1033CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1034 AddStmtChoice asc) { 1035 if (B->isLogicalOp()) { // && or || 1036 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1037 appendStmt(ConfluenceBlock, B); 1038 1039 if (badCFG) 1040 return 0; 1041 1042 // create the block evaluating the LHS 1043 CFGBlock* LHSBlock = createBlock(false); 1044 LHSBlock->setTerminator(B); 1045 1046 // create the block evaluating the RHS 1047 Succ = ConfluenceBlock; 1048 Block = NULL; 1049 CFGBlock* RHSBlock = addStmt(B->getRHS()); 1050 1051 if (RHSBlock) { 1052 if (badCFG) 1053 return 0; 1054 } else { 1055 // Create an empty block for cases where the RHS doesn't require 1056 // any explicit statements in the CFG. 1057 RHSBlock = createBlock(); 1058 } 1059 1060 // See if this is a known constant. 1061 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1062 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1063 KnownVal.negate(); 1064 1065 // Now link the LHSBlock with RHSBlock. 1066 if (B->getOpcode() == BO_LOr) { 1067 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1068 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1069 } else { 1070 assert(B->getOpcode() == BO_LAnd); 1071 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1072 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1073 } 1074 1075 // Generate the blocks for evaluating the LHS. 1076 Block = LHSBlock; 1077 return addStmt(B->getLHS()); 1078 } 1079 1080 if (B->getOpcode() == BO_Comma) { // , 1081 autoCreateBlock(); 1082 appendStmt(Block, B); 1083 addStmt(B->getRHS()); 1084 return addStmt(B->getLHS()); 1085 } 1086 1087 if (B->isAssignmentOp()) { 1088 if (asc.alwaysAdd(*this, B)) { 1089 autoCreateBlock(); 1090 appendStmt(Block, B); 1091 } 1092 Visit(B->getLHS()); 1093 return Visit(B->getRHS()); 1094 } 1095 1096 if (asc.alwaysAdd(*this, B)) { 1097 autoCreateBlock(); 1098 appendStmt(Block, B); 1099 } 1100 1101 CFGBlock *RBlock = Visit(B->getRHS()); 1102 CFGBlock *LBlock = Visit(B->getLHS()); 1103 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1104 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1105 // return RBlock. Otherwise we'll incorrectly return NULL. 1106 return (LBlock ? LBlock : RBlock); 1107} 1108 1109CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1110 if (asc.alwaysAdd(*this, E)) { 1111 autoCreateBlock(); 1112 appendStmt(Block, E); 1113 } 1114 return Block; 1115} 1116 1117CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1118 // "break" is a control-flow statement. Thus we stop processing the current 1119 // block. 1120 if (badCFG) 1121 return 0; 1122 1123 // Now create a new block that ends with the break statement. 1124 Block = createBlock(false); 1125 Block->setTerminator(B); 1126 1127 // If there is no target for the break, then we are looking at an incomplete 1128 // AST. This means that the CFG cannot be constructed. 1129 if (BreakJumpTarget.block) { 1130 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1131 addSuccessor(Block, BreakJumpTarget.block); 1132 } else 1133 badCFG = true; 1134 1135 1136 return Block; 1137} 1138 1139static bool CanThrow(Expr *E, ASTContext &Ctx) { 1140 QualType Ty = E->getType(); 1141 if (Ty->isFunctionPointerType()) 1142 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1143 else if (Ty->isBlockPointerType()) 1144 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1145 1146 const FunctionType *FT = Ty->getAs<FunctionType>(); 1147 if (FT) { 1148 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1149 if (Proto->isNothrow(Ctx)) 1150 return false; 1151 } 1152 return true; 1153} 1154 1155CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1156 // If this is a call to a no-return function, this stops the block here. 1157 bool NoReturn = false; 1158 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 1159 NoReturn = true; 1160 } 1161 1162 bool AddEHEdge = false; 1163 1164 // Languages without exceptions are assumed to not throw. 1165 if (Context->getLangOptions().Exceptions) { 1166 if (BuildOpts.AddEHEdges) 1167 AddEHEdge = true; 1168 } 1169 1170 if (FunctionDecl *FD = C->getDirectCallee()) { 1171 if (FD->hasAttr<NoReturnAttr>()) 1172 NoReturn = true; 1173 if (FD->hasAttr<NoThrowAttr>()) 1174 AddEHEdge = false; 1175 } 1176 1177 if (!CanThrow(C->getCallee(), *Context)) 1178 AddEHEdge = false; 1179 1180 if (!NoReturn && !AddEHEdge) 1181 return VisitStmt(C, asc.withAlwaysAdd(true)); 1182 1183 if (Block) { 1184 Succ = Block; 1185 if (badCFG) 1186 return 0; 1187 } 1188 1189 Block = createBlock(!NoReturn); 1190 appendStmt(Block, C); 1191 1192 if (NoReturn) { 1193 // Wire this to the exit block directly. 1194 addSuccessor(Block, &cfg->getExit()); 1195 } 1196 if (AddEHEdge) { 1197 // Add exceptional edges. 1198 if (TryTerminatedBlock) 1199 addSuccessor(Block, TryTerminatedBlock); 1200 else 1201 addSuccessor(Block, &cfg->getExit()); 1202 } 1203 1204 return VisitChildren(C); 1205} 1206 1207CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1208 AddStmtChoice asc) { 1209 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1210 appendStmt(ConfluenceBlock, C); 1211 if (badCFG) 1212 return 0; 1213 1214 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1215 Succ = ConfluenceBlock; 1216 Block = NULL; 1217 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1218 if (badCFG) 1219 return 0; 1220 1221 Succ = ConfluenceBlock; 1222 Block = NULL; 1223 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1224 if (badCFG) 1225 return 0; 1226 1227 Block = createBlock(false); 1228 // See if this is a known constant. 1229 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1230 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1231 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1232 Block->setTerminator(C); 1233 return addStmt(C->getCond()); 1234} 1235 1236 1237CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1238 addLocalScopeAndDtors(C); 1239 CFGBlock* LastBlock = Block; 1240 1241 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1242 I != E; ++I ) { 1243 // If we hit a segment of code just containing ';' (NullStmts), we can 1244 // get a null block back. In such cases, just use the LastBlock 1245 if (CFGBlock *newBlock = addStmt(*I)) 1246 LastBlock = newBlock; 1247 1248 if (badCFG) 1249 return NULL; 1250 } 1251 1252 return LastBlock; 1253} 1254 1255CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1256 AddStmtChoice asc) { 1257 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1258 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1259 1260 // Create the confluence block that will "merge" the results of the ternary 1261 // expression. 1262 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1263 appendStmt(ConfluenceBlock, C); 1264 if (badCFG) 1265 return 0; 1266 1267 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1268 1269 // Create a block for the LHS expression if there is an LHS expression. A 1270 // GCC extension allows LHS to be NULL, causing the condition to be the 1271 // value that is returned instead. 1272 // e.g: x ?: y is shorthand for: x ? x : y; 1273 Succ = ConfluenceBlock; 1274 Block = NULL; 1275 CFGBlock* LHSBlock = 0; 1276 const Expr *trueExpr = C->getTrueExpr(); 1277 if (trueExpr != opaqueValue) { 1278 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1279 if (badCFG) 1280 return 0; 1281 Block = NULL; 1282 } 1283 else 1284 LHSBlock = ConfluenceBlock; 1285 1286 // Create the block for the RHS expression. 1287 Succ = ConfluenceBlock; 1288 CFGBlock* RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1289 if (badCFG) 1290 return 0; 1291 1292 // Create the block that will contain the condition. 1293 Block = createBlock(false); 1294 1295 // See if this is a known constant. 1296 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1297 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1298 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1299 Block->setTerminator(C); 1300 Expr *condExpr = C->getCond(); 1301 1302 if (opaqueValue) { 1303 // Run the condition expression if it's not trivially expressed in 1304 // terms of the opaque value (or if there is no opaque value). 1305 if (condExpr != opaqueValue) 1306 addStmt(condExpr); 1307 1308 // Before that, run the common subexpression if there was one. 1309 // At least one of this or the above will be run. 1310 return addStmt(BCO->getCommon()); 1311 } 1312 1313 return addStmt(condExpr); 1314} 1315 1316CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1317 if (DS->isSingleDecl()) 1318 return VisitDeclSubExpr(DS); 1319 1320 CFGBlock *B = 0; 1321 1322 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1323 typedef llvm::SmallVector<Decl*,10> BufTy; 1324 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1325 1326 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1327 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1328 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1329 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1330 1331 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1332 // automatically freed with the CFG. 1333 DeclGroupRef DG(*I); 1334 Decl *D = *I; 1335 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1336 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1337 1338 // Append the fake DeclStmt to block. 1339 B = VisitDeclSubExpr(DSNew); 1340 } 1341 1342 return B; 1343} 1344 1345/// VisitDeclSubExpr - Utility method to add block-level expressions for 1346/// DeclStmts and initializers in them. 1347CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1348 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1349 1350 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1351 1352 if (!VD) { 1353 autoCreateBlock(); 1354 appendStmt(Block, DS); 1355 return Block; 1356 } 1357 1358 bool IsReference = false; 1359 bool HasTemporaries = false; 1360 1361 // Destructors of temporaries in initialization expression should be called 1362 // after initialization finishes. 1363 Expr *Init = VD->getInit(); 1364 if (Init) { 1365 IsReference = VD->getType()->isReferenceType(); 1366 HasTemporaries = isa<ExprWithCleanups>(Init); 1367 1368 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1369 // Generate destructors for temporaries in initialization expression. 1370 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1371 IsReference); 1372 } 1373 } 1374 1375 autoCreateBlock(); 1376 appendStmt(Block, DS); 1377 1378 if (Init) { 1379 if (HasTemporaries) 1380 // For expression with temporaries go directly to subexpression to omit 1381 // generating destructors for the second time. 1382 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1383 else 1384 Visit(Init); 1385 } 1386 1387 // If the type of VD is a VLA, then we must process its size expressions. 1388 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1389 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1390 Block = addStmt(VA->getSizeExpr()); 1391 1392 // Remove variable from local scope. 1393 if (ScopePos && VD == *ScopePos) 1394 ++ScopePos; 1395 1396 return Block; 1397} 1398 1399CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1400 // We may see an if statement in the middle of a basic block, or it may be the 1401 // first statement we are processing. In either case, we create a new basic 1402 // block. First, we create the blocks for the then...else statements, and 1403 // then we create the block containing the if statement. If we were in the 1404 // middle of a block, we stop processing that block. That block is then the 1405 // implicit successor for the "then" and "else" clauses. 1406 1407 // Save local scope position because in case of condition variable ScopePos 1408 // won't be restored when traversing AST. 1409 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1410 1411 // Create local scope for possible condition variable. 1412 // Store scope position. Add implicit destructor. 1413 if (VarDecl* VD = I->getConditionVariable()) { 1414 LocalScope::const_iterator BeginScopePos = ScopePos; 1415 addLocalScopeForVarDecl(VD); 1416 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1417 } 1418 1419 // The block we were processing is now finished. Make it the successor 1420 // block. 1421 if (Block) { 1422 Succ = Block; 1423 if (badCFG) 1424 return 0; 1425 } 1426 1427 // Process the false branch. 1428 CFGBlock* ElseBlock = Succ; 1429 1430 if (Stmt* Else = I->getElse()) { 1431 SaveAndRestore<CFGBlock*> sv(Succ); 1432 1433 // NULL out Block so that the recursive call to Visit will 1434 // create a new basic block. 1435 Block = NULL; 1436 1437 // If branch is not a compound statement create implicit scope 1438 // and add destructors. 1439 if (!isa<CompoundStmt>(Else)) 1440 addLocalScopeAndDtors(Else); 1441 1442 ElseBlock = addStmt(Else); 1443 1444 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1445 ElseBlock = sv.get(); 1446 else if (Block) { 1447 if (badCFG) 1448 return 0; 1449 } 1450 } 1451 1452 // Process the true branch. 1453 CFGBlock* ThenBlock; 1454 { 1455 Stmt* Then = I->getThen(); 1456 assert(Then); 1457 SaveAndRestore<CFGBlock*> sv(Succ); 1458 Block = NULL; 1459 1460 // If branch is not a compound statement create implicit scope 1461 // and add destructors. 1462 if (!isa<CompoundStmt>(Then)) 1463 addLocalScopeAndDtors(Then); 1464 1465 ThenBlock = addStmt(Then); 1466 1467 if (!ThenBlock) { 1468 // We can reach here if the "then" body has all NullStmts. 1469 // Create an empty block so we can distinguish between true and false 1470 // branches in path-sensitive analyses. 1471 ThenBlock = createBlock(false); 1472 addSuccessor(ThenBlock, sv.get()); 1473 } else if (Block) { 1474 if (badCFG) 1475 return 0; 1476 } 1477 } 1478 1479 // Now create a new block containing the if statement. 1480 Block = createBlock(false); 1481 1482 // Set the terminator of the new block to the If statement. 1483 Block->setTerminator(I); 1484 1485 // See if this is a known constant. 1486 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1487 1488 // Now add the successors. 1489 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1490 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1491 1492 // Add the condition as the last statement in the new block. This may create 1493 // new blocks as the condition may contain control-flow. Any newly created 1494 // blocks will be pointed to be "Block". 1495 Block = addStmt(I->getCond()); 1496 1497 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1498 // and the condition variable initialization to the CFG. 1499 if (VarDecl *VD = I->getConditionVariable()) { 1500 if (Expr *Init = VD->getInit()) { 1501 autoCreateBlock(); 1502 appendStmt(Block, I->getConditionVariableDeclStmt()); 1503 addStmt(Init); 1504 } 1505 } 1506 1507 return Block; 1508} 1509 1510 1511CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1512 // If we were in the middle of a block we stop processing that block. 1513 // 1514 // NOTE: If a "return" appears in the middle of a block, this means that the 1515 // code afterwards is DEAD (unreachable). We still keep a basic block 1516 // for that code; a simple "mark-and-sweep" from the entry block will be 1517 // able to report such dead blocks. 1518 1519 // Create the new block. 1520 Block = createBlock(false); 1521 1522 // The Exit block is the only successor. 1523 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1524 addSuccessor(Block, &cfg->getExit()); 1525 1526 // Add the return statement to the block. This may create new blocks if R 1527 // contains control-flow (short-circuit operations). 1528 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1529} 1530 1531CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1532 // Get the block of the labeled statement. Add it to our map. 1533 addStmt(L->getSubStmt()); 1534 CFGBlock *LabelBlock = Block; 1535 1536 if (!LabelBlock) // This can happen when the body is empty, i.e. 1537 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1538 1539 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1540 "label already in map"); 1541 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1542 1543 // Labels partition blocks, so this is the end of the basic block we were 1544 // processing (L is the block's label). Because this is label (and we have 1545 // already processed the substatement) there is no extra control-flow to worry 1546 // about. 1547 LabelBlock->setLabel(L); 1548 if (badCFG) 1549 return 0; 1550 1551 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1552 Block = NULL; 1553 1554 // This block is now the implicit successor of other blocks. 1555 Succ = LabelBlock; 1556 1557 return LabelBlock; 1558} 1559 1560CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1561 // Goto is a control-flow statement. Thus we stop processing the current 1562 // block and create a new one. 1563 1564 Block = createBlock(false); 1565 Block->setTerminator(G); 1566 1567 // If we already know the mapping to the label block add the successor now. 1568 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1569 1570 if (I == LabelMap.end()) 1571 // We will need to backpatch this block later. 1572 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1573 else { 1574 JumpTarget JT = I->second; 1575 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1576 addSuccessor(Block, JT.block); 1577 } 1578 1579 return Block; 1580} 1581 1582CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1583 CFGBlock* LoopSuccessor = NULL; 1584 1585 // Save local scope position because in case of condition variable ScopePos 1586 // won't be restored when traversing AST. 1587 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1588 1589 // Create local scope for init statement and possible condition variable. 1590 // Add destructor for init statement and condition variable. 1591 // Store scope position for continue statement. 1592 if (Stmt* Init = F->getInit()) 1593 addLocalScopeForStmt(Init); 1594 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1595 1596 if (VarDecl* VD = F->getConditionVariable()) 1597 addLocalScopeForVarDecl(VD); 1598 LocalScope::const_iterator ContinueScopePos = ScopePos; 1599 1600 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1601 1602 // "for" is a control-flow statement. Thus we stop processing the current 1603 // block. 1604 if (Block) { 1605 if (badCFG) 1606 return 0; 1607 LoopSuccessor = Block; 1608 } else 1609 LoopSuccessor = Succ; 1610 1611 // Save the current value for the break targets. 1612 // All breaks should go to the code following the loop. 1613 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1614 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1615 1616 // Because of short-circuit evaluation, the condition of the loop can span 1617 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1618 // evaluate the condition. 1619 CFGBlock* ExitConditionBlock = createBlock(false); 1620 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1621 1622 // Set the terminator for the "exit" condition block. 1623 ExitConditionBlock->setTerminator(F); 1624 1625 // Now add the actual condition to the condition block. Because the condition 1626 // itself may contain control-flow, new blocks may be created. 1627 if (Stmt* C = F->getCond()) { 1628 Block = ExitConditionBlock; 1629 EntryConditionBlock = addStmt(C); 1630 if (badCFG) 1631 return 0; 1632 assert(Block == EntryConditionBlock || 1633 (Block == 0 && EntryConditionBlock == Succ)); 1634 1635 // If this block contains a condition variable, add both the condition 1636 // variable and initializer to the CFG. 1637 if (VarDecl *VD = F->getConditionVariable()) { 1638 if (Expr *Init = VD->getInit()) { 1639 autoCreateBlock(); 1640 appendStmt(Block, F->getConditionVariableDeclStmt()); 1641 EntryConditionBlock = addStmt(Init); 1642 assert(Block == EntryConditionBlock); 1643 } 1644 } 1645 1646 if (Block) { 1647 if (badCFG) 1648 return 0; 1649 } 1650 } 1651 1652 // The condition block is the implicit successor for the loop body as well as 1653 // any code above the loop. 1654 Succ = EntryConditionBlock; 1655 1656 // See if this is a known constant. 1657 TryResult KnownVal(true); 1658 1659 if (F->getCond()) 1660 KnownVal = tryEvaluateBool(F->getCond()); 1661 1662 // Now create the loop body. 1663 { 1664 assert(F->getBody()); 1665 1666 // Save the current values for Block, Succ, and continue targets. 1667 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1668 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1669 1670 // Create a new block to contain the (bottom) of the loop body. 1671 Block = NULL; 1672 1673 // Loop body should end with destructor of Condition variable (if any). 1674 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1675 1676 if (Stmt* I = F->getInc()) { 1677 // Generate increment code in its own basic block. This is the target of 1678 // continue statements. 1679 Succ = addStmt(I); 1680 } else { 1681 // No increment code. Create a special, empty, block that is used as the 1682 // target block for "looping back" to the start of the loop. 1683 assert(Succ == EntryConditionBlock); 1684 Succ = Block ? Block : createBlock(); 1685 } 1686 1687 // Finish up the increment (or empty) block if it hasn't been already. 1688 if (Block) { 1689 assert(Block == Succ); 1690 if (badCFG) 1691 return 0; 1692 Block = 0; 1693 } 1694 1695 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1696 1697 // The starting block for the loop increment is the block that should 1698 // represent the 'loop target' for looping back to the start of the loop. 1699 ContinueJumpTarget.block->setLoopTarget(F); 1700 1701 // If body is not a compound statement create implicit scope 1702 // and add destructors. 1703 if (!isa<CompoundStmt>(F->getBody())) 1704 addLocalScopeAndDtors(F->getBody()); 1705 1706 // Now populate the body block, and in the process create new blocks as we 1707 // walk the body of the loop. 1708 CFGBlock* BodyBlock = addStmt(F->getBody()); 1709 1710 if (!BodyBlock) 1711 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1712 else if (badCFG) 1713 return 0; 1714 1715 // This new body block is a successor to our "exit" condition block. 1716 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1717 } 1718 1719 // Link up the condition block with the code that follows the loop. (the 1720 // false branch). 1721 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1722 1723 // If the loop contains initialization, create a new block for those 1724 // statements. This block can also contain statements that precede the loop. 1725 if (Stmt* I = F->getInit()) { 1726 Block = createBlock(); 1727 return addStmt(I); 1728 } 1729 1730 // There is no loop initialization. We are thus basically a while loop. 1731 // NULL out Block to force lazy block construction. 1732 Block = NULL; 1733 Succ = EntryConditionBlock; 1734 return EntryConditionBlock; 1735} 1736 1737CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1738 if (asc.alwaysAdd(*this, M)) { 1739 autoCreateBlock(); 1740 appendStmt(Block, M); 1741 } 1742 return Visit(M->getBase()); 1743} 1744 1745CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1746 // Objective-C fast enumeration 'for' statements: 1747 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1748 // 1749 // for ( Type newVariable in collection_expression ) { statements } 1750 // 1751 // becomes: 1752 // 1753 // prologue: 1754 // 1. collection_expression 1755 // T. jump to loop_entry 1756 // loop_entry: 1757 // 1. side-effects of element expression 1758 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1759 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1760 // TB: 1761 // statements 1762 // T. jump to loop_entry 1763 // FB: 1764 // what comes after 1765 // 1766 // and 1767 // 1768 // Type existingItem; 1769 // for ( existingItem in expression ) { statements } 1770 // 1771 // becomes: 1772 // 1773 // the same with newVariable replaced with existingItem; the binding works 1774 // the same except that for one ObjCForCollectionStmt::getElement() returns 1775 // a DeclStmt and the other returns a DeclRefExpr. 1776 // 1777 1778 CFGBlock* LoopSuccessor = 0; 1779 1780 if (Block) { 1781 if (badCFG) 1782 return 0; 1783 LoopSuccessor = Block; 1784 Block = 0; 1785 } else 1786 LoopSuccessor = Succ; 1787 1788 // Build the condition blocks. 1789 CFGBlock* ExitConditionBlock = createBlock(false); 1790 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1791 1792 // Set the terminator for the "exit" condition block. 1793 ExitConditionBlock->setTerminator(S); 1794 1795 // The last statement in the block should be the ObjCForCollectionStmt, which 1796 // performs the actual binding to 'element' and determines if there are any 1797 // more items in the collection. 1798 appendStmt(ExitConditionBlock, S); 1799 Block = ExitConditionBlock; 1800 1801 // Walk the 'element' expression to see if there are any side-effects. We 1802 // generate new blocks as necessary. We DON'T add the statement by default to 1803 // the CFG unless it contains control-flow. 1804 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1805 if (Block) { 1806 if (badCFG) 1807 return 0; 1808 Block = 0; 1809 } 1810 1811 // The condition block is the implicit successor for the loop body as well as 1812 // any code above the loop. 1813 Succ = EntryConditionBlock; 1814 1815 // Now create the true branch. 1816 { 1817 // Save the current values for Succ, continue and break targets. 1818 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1819 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1820 save_break(BreakJumpTarget); 1821 1822 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1823 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1824 1825 CFGBlock* BodyBlock = addStmt(S->getBody()); 1826 1827 if (!BodyBlock) 1828 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1829 else if (Block) { 1830 if (badCFG) 1831 return 0; 1832 } 1833 1834 // This new body block is a successor to our "exit" condition block. 1835 addSuccessor(ExitConditionBlock, BodyBlock); 1836 } 1837 1838 // Link up the condition block with the code that follows the loop. 1839 // (the false branch). 1840 addSuccessor(ExitConditionBlock, LoopSuccessor); 1841 1842 // Now create a prologue block to contain the collection expression. 1843 Block = createBlock(); 1844 return addStmt(S->getCollection()); 1845} 1846 1847CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1848 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1849 1850 // Inline the body. 1851 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1852 1853 // The sync body starts its own basic block. This makes it a little easier 1854 // for diagnostic clients. 1855 if (SyncBlock) { 1856 if (badCFG) 1857 return 0; 1858 1859 Block = 0; 1860 Succ = SyncBlock; 1861 } 1862 1863 // Add the @synchronized to the CFG. 1864 autoCreateBlock(); 1865 appendStmt(Block, S); 1866 1867 // Inline the sync expression. 1868 return addStmt(S->getSynchExpr()); 1869} 1870 1871CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1872 // FIXME 1873 return NYS(); 1874} 1875 1876CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1877 CFGBlock* LoopSuccessor = NULL; 1878 1879 // Save local scope position because in case of condition variable ScopePos 1880 // won't be restored when traversing AST. 1881 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1882 1883 // Create local scope for possible condition variable. 1884 // Store scope position for continue statement. 1885 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1886 if (VarDecl* VD = W->getConditionVariable()) { 1887 addLocalScopeForVarDecl(VD); 1888 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1889 } 1890 1891 // "while" is a control-flow statement. Thus we stop processing the current 1892 // block. 1893 if (Block) { 1894 if (badCFG) 1895 return 0; 1896 LoopSuccessor = Block; 1897 Block = 0; 1898 } else 1899 LoopSuccessor = Succ; 1900 1901 // Because of short-circuit evaluation, the condition of the loop can span 1902 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1903 // evaluate the condition. 1904 CFGBlock* ExitConditionBlock = createBlock(false); 1905 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1906 1907 // Set the terminator for the "exit" condition block. 1908 ExitConditionBlock->setTerminator(W); 1909 1910 // Now add the actual condition to the condition block. Because the condition 1911 // itself may contain control-flow, new blocks may be created. Thus we update 1912 // "Succ" after adding the condition. 1913 if (Stmt* C = W->getCond()) { 1914 Block = ExitConditionBlock; 1915 EntryConditionBlock = addStmt(C); 1916 // The condition might finish the current 'Block'. 1917 Block = EntryConditionBlock; 1918 1919 // If this block contains a condition variable, add both the condition 1920 // variable and initializer to the CFG. 1921 if (VarDecl *VD = W->getConditionVariable()) { 1922 if (Expr *Init = VD->getInit()) { 1923 autoCreateBlock(); 1924 appendStmt(Block, W->getConditionVariableDeclStmt()); 1925 EntryConditionBlock = addStmt(Init); 1926 assert(Block == EntryConditionBlock); 1927 } 1928 } 1929 1930 if (Block) { 1931 if (badCFG) 1932 return 0; 1933 } 1934 } 1935 1936 // The condition block is the implicit successor for the loop body as well as 1937 // any code above the loop. 1938 Succ = EntryConditionBlock; 1939 1940 // See if this is a known constant. 1941 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1942 1943 // Process the loop body. 1944 { 1945 assert(W->getBody()); 1946 1947 // Save the current values for Block, Succ, and continue and break targets 1948 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1949 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1950 save_break(BreakJumpTarget); 1951 1952 // Create an empty block to represent the transition block for looping back 1953 // to the head of the loop. 1954 Block = 0; 1955 assert(Succ == EntryConditionBlock); 1956 Succ = createBlock(); 1957 Succ->setLoopTarget(W); 1958 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1959 1960 // All breaks should go to the code following the loop. 1961 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1962 1963 // NULL out Block to force lazy instantiation of blocks for the body. 1964 Block = NULL; 1965 1966 // Loop body should end with destructor of Condition variable (if any). 1967 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1968 1969 // If body is not a compound statement create implicit scope 1970 // and add destructors. 1971 if (!isa<CompoundStmt>(W->getBody())) 1972 addLocalScopeAndDtors(W->getBody()); 1973 1974 // Create the body. The returned block is the entry to the loop body. 1975 CFGBlock* BodyBlock = addStmt(W->getBody()); 1976 1977 if (!BodyBlock) 1978 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 1979 else if (Block) { 1980 if (badCFG) 1981 return 0; 1982 } 1983 1984 // Add the loop body entry as a successor to the condition. 1985 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1986 } 1987 1988 // Link up the condition block with the code that follows the loop. (the 1989 // false branch). 1990 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1991 1992 // There can be no more statements in the condition block since we loop back 1993 // to this block. NULL out Block to force lazy creation of another block. 1994 Block = NULL; 1995 1996 // Return the condition block, which is the dominating block for the loop. 1997 Succ = EntryConditionBlock; 1998 return EntryConditionBlock; 1999} 2000 2001 2002CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 2003 // FIXME: For now we pretend that @catch and the code it contains does not 2004 // exit. 2005 return Block; 2006} 2007 2008CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 2009 // FIXME: This isn't complete. We basically treat @throw like a return 2010 // statement. 2011 2012 // If we were in the middle of a block we stop processing that block. 2013 if (badCFG) 2014 return 0; 2015 2016 // Create the new block. 2017 Block = createBlock(false); 2018 2019 // The Exit block is the only successor. 2020 addSuccessor(Block, &cfg->getExit()); 2021 2022 // Add the statement to the block. This may create new blocks if S contains 2023 // control-flow (short-circuit operations). 2024 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2025} 2026 2027CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 2028 // If we were in the middle of a block we stop processing that block. 2029 if (badCFG) 2030 return 0; 2031 2032 // Create the new block. 2033 Block = createBlock(false); 2034 2035 if (TryTerminatedBlock) 2036 // The current try statement is the only successor. 2037 addSuccessor(Block, TryTerminatedBlock); 2038 else 2039 // otherwise the Exit block is the only successor. 2040 addSuccessor(Block, &cfg->getExit()); 2041 2042 // Add the statement to the block. This may create new blocks if S contains 2043 // control-flow (short-circuit operations). 2044 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2045} 2046 2047CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 2048 CFGBlock* LoopSuccessor = NULL; 2049 2050 // "do...while" is a control-flow statement. Thus we stop processing the 2051 // current block. 2052 if (Block) { 2053 if (badCFG) 2054 return 0; 2055 LoopSuccessor = Block; 2056 } else 2057 LoopSuccessor = Succ; 2058 2059 // Because of short-circuit evaluation, the condition of the loop can span 2060 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2061 // evaluate the condition. 2062 CFGBlock* ExitConditionBlock = createBlock(false); 2063 CFGBlock* EntryConditionBlock = ExitConditionBlock; 2064 2065 // Set the terminator for the "exit" condition block. 2066 ExitConditionBlock->setTerminator(D); 2067 2068 // Now add the actual condition to the condition block. Because the condition 2069 // itself may contain control-flow, new blocks may be created. 2070 if (Stmt* C = D->getCond()) { 2071 Block = ExitConditionBlock; 2072 EntryConditionBlock = addStmt(C); 2073 if (Block) { 2074 if (badCFG) 2075 return 0; 2076 } 2077 } 2078 2079 // The condition block is the implicit successor for the loop body. 2080 Succ = EntryConditionBlock; 2081 2082 // See if this is a known constant. 2083 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2084 2085 // Process the loop body. 2086 CFGBlock* BodyBlock = NULL; 2087 { 2088 assert(D->getBody()); 2089 2090 // Save the current values for Block, Succ, and continue and break targets 2091 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2092 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2093 save_break(BreakJumpTarget); 2094 2095 // All continues within this loop should go to the condition block 2096 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2097 2098 // All breaks should go to the code following the loop. 2099 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2100 2101 // NULL out Block to force lazy instantiation of blocks for the body. 2102 Block = NULL; 2103 2104 // If body is not a compound statement create implicit scope 2105 // and add destructors. 2106 if (!isa<CompoundStmt>(D->getBody())) 2107 addLocalScopeAndDtors(D->getBody()); 2108 2109 // Create the body. The returned block is the entry to the loop body. 2110 BodyBlock = addStmt(D->getBody()); 2111 2112 if (!BodyBlock) 2113 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2114 else if (Block) { 2115 if (badCFG) 2116 return 0; 2117 } 2118 2119 if (!KnownVal.isFalse()) { 2120 // Add an intermediate block between the BodyBlock and the 2121 // ExitConditionBlock to represent the "loop back" transition. Create an 2122 // empty block to represent the transition block for looping back to the 2123 // head of the loop. 2124 // FIXME: Can we do this more efficiently without adding another block? 2125 Block = NULL; 2126 Succ = BodyBlock; 2127 CFGBlock *LoopBackBlock = createBlock(); 2128 LoopBackBlock->setLoopTarget(D); 2129 2130 // Add the loop body entry as a successor to the condition. 2131 addSuccessor(ExitConditionBlock, LoopBackBlock); 2132 } 2133 else 2134 addSuccessor(ExitConditionBlock, NULL); 2135 } 2136 2137 // Link up the condition block with the code that follows the loop. 2138 // (the false branch). 2139 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2140 2141 // There can be no more statements in the body block(s) since we loop back to 2142 // the body. NULL out Block to force lazy creation of another block. 2143 Block = NULL; 2144 2145 // Return the loop body, which is the dominating block for the loop. 2146 Succ = BodyBlock; 2147 return BodyBlock; 2148} 2149 2150CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2151 // "continue" is a control-flow statement. Thus we stop processing the 2152 // current block. 2153 if (badCFG) 2154 return 0; 2155 2156 // Now create a new block that ends with the continue statement. 2157 Block = createBlock(false); 2158 Block->setTerminator(C); 2159 2160 // If there is no target for the continue, then we are looking at an 2161 // incomplete AST. This means the CFG cannot be constructed. 2162 if (ContinueJumpTarget.block) { 2163 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2164 addSuccessor(Block, ContinueJumpTarget.block); 2165 } else 2166 badCFG = true; 2167 2168 return Block; 2169} 2170 2171CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2172 AddStmtChoice asc) { 2173 2174 if (asc.alwaysAdd(*this, E)) { 2175 autoCreateBlock(); 2176 appendStmt(Block, E); 2177 } 2178 2179 // VLA types have expressions that must be evaluated. 2180 CFGBlock *lastBlock = Block; 2181 2182 if (E->isArgumentType()) { 2183 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2184 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2185 lastBlock = addStmt(VA->getSizeExpr()); 2186 } 2187 2188 return lastBlock; 2189} 2190 2191/// VisitStmtExpr - Utility method to handle (nested) statement 2192/// expressions (a GCC extension). 2193CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2194 if (asc.alwaysAdd(*this, SE)) { 2195 autoCreateBlock(); 2196 appendStmt(Block, SE); 2197 } 2198 return VisitCompoundStmt(SE->getSubStmt()); 2199} 2200 2201CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2202 // "switch" is a control-flow statement. Thus we stop processing the current 2203 // block. 2204 CFGBlock* SwitchSuccessor = NULL; 2205 2206 // Save local scope position because in case of condition variable ScopePos 2207 // won't be restored when traversing AST. 2208 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2209 2210 // Create local scope for possible condition variable. 2211 // Store scope position. Add implicit destructor. 2212 if (VarDecl* VD = Terminator->getConditionVariable()) { 2213 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2214 addLocalScopeForVarDecl(VD); 2215 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2216 } 2217 2218 if (Block) { 2219 if (badCFG) 2220 return 0; 2221 SwitchSuccessor = Block; 2222 } else SwitchSuccessor = Succ; 2223 2224 // Save the current "switch" context. 2225 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2226 save_default(DefaultCaseBlock); 2227 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2228 2229 // Set the "default" case to be the block after the switch statement. If the 2230 // switch statement contains a "default:", this value will be overwritten with 2231 // the block for that code. 2232 DefaultCaseBlock = SwitchSuccessor; 2233 2234 // Create a new block that will contain the switch statement. 2235 SwitchTerminatedBlock = createBlock(false); 2236 2237 // Now process the switch body. The code after the switch is the implicit 2238 // successor. 2239 Succ = SwitchSuccessor; 2240 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2241 2242 // When visiting the body, the case statements should automatically get linked 2243 // up to the switch. We also don't keep a pointer to the body, since all 2244 // control-flow from the switch goes to case/default statements. 2245 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2246 Block = NULL; 2247 2248 // For pruning unreachable case statements, save the current state 2249 // for tracking the condition value. 2250 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2251 false); 2252 2253 // Determine if the switch condition can be explicitly evaluated. 2254 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2255 Expr::EvalResult result; 2256 bool b = tryEvaluate(Terminator->getCond(), result); 2257 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2258 b ? &result : 0); 2259 2260 // If body is not a compound statement create implicit scope 2261 // and add destructors. 2262 if (!isa<CompoundStmt>(Terminator->getBody())) 2263 addLocalScopeAndDtors(Terminator->getBody()); 2264 2265 addStmt(Terminator->getBody()); 2266 if (Block) { 2267 if (badCFG) 2268 return 0; 2269 } 2270 2271 // If we have no "default:" case, the default transition is to the code 2272 // following the switch body. Moreover, take into account if all the 2273 // cases of a switch are covered (e.g., switching on an enum value). 2274 addSuccessor(SwitchTerminatedBlock, 2275 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2276 ? 0 : DefaultCaseBlock); 2277 2278 // Add the terminator and condition in the switch block. 2279 SwitchTerminatedBlock->setTerminator(Terminator); 2280 Block = SwitchTerminatedBlock; 2281 Block = addStmt(Terminator->getCond()); 2282 2283 // Finally, if the SwitchStmt contains a condition variable, add both the 2284 // SwitchStmt and the condition variable initialization to the CFG. 2285 if (VarDecl *VD = Terminator->getConditionVariable()) { 2286 if (Expr *Init = VD->getInit()) { 2287 autoCreateBlock(); 2288 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2289 addStmt(Init); 2290 } 2291 } 2292 2293 return Block; 2294} 2295 2296static bool shouldAddCase(bool &switchExclusivelyCovered, 2297 const Expr::EvalResult *switchCond, 2298 const CaseStmt *CS, 2299 ASTContext &Ctx) { 2300 if (!switchCond) 2301 return true; 2302 2303 bool addCase = false; 2304 2305 if (!switchExclusivelyCovered) { 2306 if (switchCond->Val.isInt()) { 2307 // Evaluate the LHS of the case value. 2308 Expr::EvalResult V1; 2309 CS->getLHS()->Evaluate(V1, Ctx); 2310 assert(V1.Val.isInt()); 2311 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2312 const llvm::APSInt &lhsInt = V1.Val.getInt(); 2313 2314 if (condInt == lhsInt) { 2315 addCase = true; 2316 switchExclusivelyCovered = true; 2317 } 2318 else if (condInt < lhsInt) { 2319 if (const Expr *RHS = CS->getRHS()) { 2320 // Evaluate the RHS of the case value. 2321 Expr::EvalResult V2; 2322 RHS->Evaluate(V2, Ctx); 2323 assert(V2.Val.isInt()); 2324 if (V2.Val.getInt() <= condInt) { 2325 addCase = true; 2326 switchExclusivelyCovered = true; 2327 } 2328 } 2329 } 2330 } 2331 else 2332 addCase = true; 2333 } 2334 return addCase; 2335} 2336 2337CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2338 // CaseStmts are essentially labels, so they are the first statement in a 2339 // block. 2340 CFGBlock *TopBlock = 0, *LastBlock = 0; 2341 2342 if (Stmt *Sub = CS->getSubStmt()) { 2343 // For deeply nested chains of CaseStmts, instead of doing a recursion 2344 // (which can blow out the stack), manually unroll and create blocks 2345 // along the way. 2346 while (isa<CaseStmt>(Sub)) { 2347 CFGBlock *currentBlock = createBlock(false); 2348 currentBlock->setLabel(CS); 2349 2350 if (TopBlock) 2351 addSuccessor(LastBlock, currentBlock); 2352 else 2353 TopBlock = currentBlock; 2354 2355 addSuccessor(SwitchTerminatedBlock, 2356 shouldAddCase(switchExclusivelyCovered, switchCond, 2357 CS, *Context) 2358 ? currentBlock : 0); 2359 2360 LastBlock = currentBlock; 2361 CS = cast<CaseStmt>(Sub); 2362 Sub = CS->getSubStmt(); 2363 } 2364 2365 addStmt(Sub); 2366 } 2367 2368 CFGBlock* CaseBlock = Block; 2369 if (!CaseBlock) 2370 CaseBlock = createBlock(); 2371 2372 // Cases statements partition blocks, so this is the top of the basic block we 2373 // were processing (the "case XXX:" is the label). 2374 CaseBlock->setLabel(CS); 2375 2376 if (badCFG) 2377 return 0; 2378 2379 // Add this block to the list of successors for the block with the switch 2380 // statement. 2381 assert(SwitchTerminatedBlock); 2382 addSuccessor(SwitchTerminatedBlock, 2383 shouldAddCase(switchExclusivelyCovered, switchCond, 2384 CS, *Context) 2385 ? CaseBlock : 0); 2386 2387 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2388 Block = NULL; 2389 2390 if (TopBlock) { 2391 addSuccessor(LastBlock, CaseBlock); 2392 Succ = TopBlock; 2393 } else { 2394 // This block is now the implicit successor of other blocks. 2395 Succ = CaseBlock; 2396 } 2397 2398 return Succ; 2399} 2400 2401CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2402 if (Terminator->getSubStmt()) 2403 addStmt(Terminator->getSubStmt()); 2404 2405 DefaultCaseBlock = Block; 2406 2407 if (!DefaultCaseBlock) 2408 DefaultCaseBlock = createBlock(); 2409 2410 // Default statements partition blocks, so this is the top of the basic block 2411 // we were processing (the "default:" is the label). 2412 DefaultCaseBlock->setLabel(Terminator); 2413 2414 if (badCFG) 2415 return 0; 2416 2417 // Unlike case statements, we don't add the default block to the successors 2418 // for the switch statement immediately. This is done when we finish 2419 // processing the switch statement. This allows for the default case 2420 // (including a fall-through to the code after the switch statement) to always 2421 // be the last successor of a switch-terminated block. 2422 2423 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2424 Block = NULL; 2425 2426 // This block is now the implicit successor of other blocks. 2427 Succ = DefaultCaseBlock; 2428 2429 return DefaultCaseBlock; 2430} 2431 2432CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2433 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2434 // current block. 2435 CFGBlock* TrySuccessor = NULL; 2436 2437 if (Block) { 2438 if (badCFG) 2439 return 0; 2440 TrySuccessor = Block; 2441 } else TrySuccessor = Succ; 2442 2443 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2444 2445 // Create a new block that will contain the try statement. 2446 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2447 // Add the terminator in the try block. 2448 NewTryTerminatedBlock->setTerminator(Terminator); 2449 2450 bool HasCatchAll = false; 2451 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2452 // The code after the try is the implicit successor. 2453 Succ = TrySuccessor; 2454 CXXCatchStmt *CS = Terminator->getHandler(h); 2455 if (CS->getExceptionDecl() == 0) { 2456 HasCatchAll = true; 2457 } 2458 Block = NULL; 2459 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2460 if (CatchBlock == 0) 2461 return 0; 2462 // Add this block to the list of successors for the block with the try 2463 // statement. 2464 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2465 } 2466 if (!HasCatchAll) { 2467 if (PrevTryTerminatedBlock) 2468 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2469 else 2470 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2471 } 2472 2473 // The code after the try is the implicit successor. 2474 Succ = TrySuccessor; 2475 2476 // Save the current "try" context. 2477 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2478 TryTerminatedBlock = NewTryTerminatedBlock; 2479 2480 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2481 Block = NULL; 2482 Block = addStmt(Terminator->getTryBlock()); 2483 return Block; 2484} 2485 2486CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2487 // CXXCatchStmt are treated like labels, so they are the first statement in a 2488 // block. 2489 2490 // Save local scope position because in case of exception variable ScopePos 2491 // won't be restored when traversing AST. 2492 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2493 2494 // Create local scope for possible exception variable. 2495 // Store scope position. Add implicit destructor. 2496 if (VarDecl* VD = CS->getExceptionDecl()) { 2497 LocalScope::const_iterator BeginScopePos = ScopePos; 2498 addLocalScopeForVarDecl(VD); 2499 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2500 } 2501 2502 if (CS->getHandlerBlock()) 2503 addStmt(CS->getHandlerBlock()); 2504 2505 CFGBlock* CatchBlock = Block; 2506 if (!CatchBlock) 2507 CatchBlock = createBlock(); 2508 2509 CatchBlock->setLabel(CS); 2510 2511 if (badCFG) 2512 return 0; 2513 2514 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2515 Block = NULL; 2516 2517 return CatchBlock; 2518} 2519 2520CFGBlock* CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt* S) { 2521 // C++0x for-range statements are specified as [stmt.ranged]: 2522 // 2523 // { 2524 // auto && __range = range-init; 2525 // for ( auto __begin = begin-expr, 2526 // __end = end-expr; 2527 // __begin != __end; 2528 // ++__begin ) { 2529 // for-range-declaration = *__begin; 2530 // statement 2531 // } 2532 // } 2533 2534 // Save local scope position before the addition of the implicit variables. 2535 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2536 2537 // Create local scopes and destructors for range, begin and end variables. 2538 if (Stmt *Range = S->getRangeStmt()) 2539 addLocalScopeForStmt(Range); 2540 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2541 addLocalScopeForStmt(BeginEnd); 2542 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2543 2544 LocalScope::const_iterator ContinueScopePos = ScopePos; 2545 2546 // "for" is a control-flow statement. Thus we stop processing the current 2547 // block. 2548 CFGBlock* LoopSuccessor = NULL; 2549 if (Block) { 2550 if (badCFG) 2551 return 0; 2552 LoopSuccessor = Block; 2553 } else 2554 LoopSuccessor = Succ; 2555 2556 // Save the current value for the break targets. 2557 // All breaks should go to the code following the loop. 2558 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2559 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2560 2561 // The block for the __begin != __end expression. 2562 CFGBlock* ConditionBlock = createBlock(false); 2563 ConditionBlock->setTerminator(S); 2564 2565 // Now add the actual condition to the condition block. 2566 if (Expr *C = S->getCond()) { 2567 Block = ConditionBlock; 2568 CFGBlock *BeginConditionBlock = addStmt(C); 2569 if (badCFG) 2570 return 0; 2571 assert(BeginConditionBlock == ConditionBlock && 2572 "condition block in for-range was unexpectedly complex"); 2573 (void)BeginConditionBlock; 2574 } 2575 2576 // The condition block is the implicit successor for the loop body as well as 2577 // any code above the loop. 2578 Succ = ConditionBlock; 2579 2580 // See if this is a known constant. 2581 TryResult KnownVal(true); 2582 2583 if (S->getCond()) 2584 KnownVal = tryEvaluateBool(S->getCond()); 2585 2586 // Now create the loop body. 2587 { 2588 assert(S->getBody()); 2589 2590 // Save the current values for Block, Succ, and continue targets. 2591 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2592 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2593 2594 // Generate increment code in its own basic block. This is the target of 2595 // continue statements. 2596 Block = 0; 2597 Succ = addStmt(S->getInc()); 2598 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2599 2600 // The starting block for the loop increment is the block that should 2601 // represent the 'loop target' for looping back to the start of the loop. 2602 ContinueJumpTarget.block->setLoopTarget(S); 2603 2604 // Finish up the increment block and prepare to start the loop body. 2605 assert(Block); 2606 if (badCFG) 2607 return 0; 2608 Block = 0; 2609 2610 2611 // Add implicit scope and dtors for loop variable. 2612 addLocalScopeAndDtors(S->getLoopVarStmt()); 2613 2614 // Populate a new block to contain the loop body and loop variable. 2615 Block = addStmt(S->getBody()); 2616 if (badCFG) 2617 return 0; 2618 Block = addStmt(S->getLoopVarStmt()); 2619 if (badCFG) 2620 return 0; 2621 2622 // This new body block is a successor to our condition block. 2623 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2624 } 2625 2626 // Link up the condition block with the code that follows the loop (the 2627 // false branch). 2628 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2629 2630 // Add the initialization statements. 2631 Block = createBlock(); 2632 addStmt(S->getBeginEndStmt()); 2633 return addStmt(S->getRangeStmt()); 2634} 2635 2636CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2637 AddStmtChoice asc) { 2638 if (BuildOpts.AddImplicitDtors) { 2639 // If adding implicit destructors visit the full expression for adding 2640 // destructors of temporaries. 2641 VisitForTemporaryDtors(E->getSubExpr()); 2642 2643 // Full expression has to be added as CFGStmt so it will be sequenced 2644 // before destructors of it's temporaries. 2645 asc = asc.withAlwaysAdd(true); 2646 } 2647 return Visit(E->getSubExpr(), asc); 2648} 2649 2650CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2651 AddStmtChoice asc) { 2652 if (asc.alwaysAdd(*this, E)) { 2653 autoCreateBlock(); 2654 appendStmt(Block, E); 2655 2656 // We do not want to propagate the AlwaysAdd property. 2657 asc = asc.withAlwaysAdd(false); 2658 } 2659 return Visit(E->getSubExpr(), asc); 2660} 2661 2662CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2663 AddStmtChoice asc) { 2664 autoCreateBlock(); 2665 if (!C->isElidable()) 2666 appendStmt(Block, C); 2667 2668 return VisitChildren(C); 2669} 2670 2671CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2672 AddStmtChoice asc) { 2673 if (asc.alwaysAdd(*this, E)) { 2674 autoCreateBlock(); 2675 appendStmt(Block, E); 2676 // We do not want to propagate the AlwaysAdd property. 2677 asc = asc.withAlwaysAdd(false); 2678 } 2679 return Visit(E->getSubExpr(), asc); 2680} 2681 2682CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2683 AddStmtChoice asc) { 2684 autoCreateBlock(); 2685 appendStmt(Block, C); 2686 return VisitChildren(C); 2687} 2688 2689CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2690 AddStmtChoice asc) { 2691 autoCreateBlock(); 2692 appendStmt(Block, C); 2693 return VisitChildren(C); 2694} 2695 2696CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2697 AddStmtChoice asc) { 2698 if (asc.alwaysAdd(*this, E)) { 2699 autoCreateBlock(); 2700 appendStmt(Block, E); 2701 } 2702 return Visit(E->getSubExpr(), AddStmtChoice()); 2703} 2704 2705CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2706 // Lazily create the indirect-goto dispatch block if there isn't one already. 2707 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2708 2709 if (!IBlock) { 2710 IBlock = createBlock(false); 2711 cfg->setIndirectGotoBlock(IBlock); 2712 } 2713 2714 // IndirectGoto is a control-flow statement. Thus we stop processing the 2715 // current block and create a new one. 2716 if (badCFG) 2717 return 0; 2718 2719 Block = createBlock(false); 2720 Block->setTerminator(I); 2721 addSuccessor(Block, IBlock); 2722 return addStmt(I->getTarget()); 2723} 2724 2725CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2726tryAgain: 2727 if (!E) { 2728 badCFG = true; 2729 return NULL; 2730 } 2731 switch (E->getStmtClass()) { 2732 default: 2733 return VisitChildrenForTemporaryDtors(E); 2734 2735 case Stmt::BinaryOperatorClass: 2736 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2737 2738 case Stmt::CXXBindTemporaryExprClass: 2739 return VisitCXXBindTemporaryExprForTemporaryDtors( 2740 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2741 2742 case Stmt::BinaryConditionalOperatorClass: 2743 case Stmt::ConditionalOperatorClass: 2744 return VisitConditionalOperatorForTemporaryDtors( 2745 cast<AbstractConditionalOperator>(E), BindToTemporary); 2746 2747 case Stmt::ImplicitCastExprClass: 2748 // For implicit cast we want BindToTemporary to be passed further. 2749 E = cast<CastExpr>(E)->getSubExpr(); 2750 goto tryAgain; 2751 2752 case Stmt::ParenExprClass: 2753 E = cast<ParenExpr>(E)->getSubExpr(); 2754 goto tryAgain; 2755 } 2756} 2757 2758CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2759 // When visiting children for destructors we want to visit them in reverse 2760 // order. Because there's no reverse iterator for children must to reverse 2761 // them in helper vector. 2762 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2763 ChildrenVect ChildrenRev; 2764 for (Stmt::child_range I = E->children(); I; ++I) { 2765 if (*I) ChildrenRev.push_back(*I); 2766 } 2767 2768 CFGBlock *B = Block; 2769 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2770 L = ChildrenRev.rend(); I != L; ++I) { 2771 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2772 B = R; 2773 } 2774 return B; 2775} 2776 2777CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2778 if (E->isLogicalOp()) { 2779 // Destructors for temporaries in LHS expression should be called after 2780 // those for RHS expression. Even if this will unnecessarily create a block, 2781 // this block will be used at least by the full expression. 2782 autoCreateBlock(); 2783 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2784 if (badCFG) 2785 return NULL; 2786 2787 Succ = ConfluenceBlock; 2788 Block = NULL; 2789 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2790 2791 if (RHSBlock) { 2792 if (badCFG) 2793 return NULL; 2794 2795 // If RHS expression did produce destructors we need to connect created 2796 // blocks to CFG in same manner as for binary operator itself. 2797 CFGBlock *LHSBlock = createBlock(false); 2798 LHSBlock->setTerminator(CFGTerminator(E, true)); 2799 2800 // For binary operator LHS block is before RHS in list of predecessors 2801 // of ConfluenceBlock. 2802 std::reverse(ConfluenceBlock->pred_begin(), 2803 ConfluenceBlock->pred_end()); 2804 2805 // See if this is a known constant. 2806 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2807 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2808 KnownVal.negate(); 2809 2810 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2811 // itself. 2812 if (E->getOpcode() == BO_LOr) { 2813 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2814 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2815 } else { 2816 assert (E->getOpcode() == BO_LAnd); 2817 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2818 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2819 } 2820 2821 Block = LHSBlock; 2822 return LHSBlock; 2823 } 2824 2825 Block = ConfluenceBlock; 2826 return ConfluenceBlock; 2827 } 2828 2829 if (E->isAssignmentOp()) { 2830 // For assignment operator (=) LHS expression is visited 2831 // before RHS expression. For destructors visit them in reverse order. 2832 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2833 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2834 return LHSBlock ? LHSBlock : RHSBlock; 2835 } 2836 2837 // For any other binary operator RHS expression is visited before 2838 // LHS expression (order of children). For destructors visit them in reverse 2839 // order. 2840 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2841 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2842 return RHSBlock ? RHSBlock : LHSBlock; 2843} 2844 2845CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2846 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2847 // First add destructors for temporaries in subexpression. 2848 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2849 if (!BindToTemporary) { 2850 // If lifetime of temporary is not prolonged (by assigning to constant 2851 // reference) add destructor for it. 2852 autoCreateBlock(); 2853 appendTemporaryDtor(Block, E); 2854 B = Block; 2855 } 2856 return B; 2857} 2858 2859CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2860 AbstractConditionalOperator *E, bool BindToTemporary) { 2861 // First add destructors for condition expression. Even if this will 2862 // unnecessarily create a block, this block will be used at least by the full 2863 // expression. 2864 autoCreateBlock(); 2865 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2866 if (badCFG) 2867 return NULL; 2868 if (BinaryConditionalOperator *BCO 2869 = dyn_cast<BinaryConditionalOperator>(E)) { 2870 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2871 if (badCFG) 2872 return NULL; 2873 } 2874 2875 // Try to add block with destructors for LHS expression. 2876 CFGBlock *LHSBlock = NULL; 2877 Succ = ConfluenceBlock; 2878 Block = NULL; 2879 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2880 if (badCFG) 2881 return NULL; 2882 2883 // Try to add block with destructors for RHS expression; 2884 Succ = ConfluenceBlock; 2885 Block = NULL; 2886 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2887 BindToTemporary); 2888 if (badCFG) 2889 return NULL; 2890 2891 if (!RHSBlock && !LHSBlock) { 2892 // If neither LHS nor RHS expression had temporaries to destroy don't create 2893 // more blocks. 2894 Block = ConfluenceBlock; 2895 return Block; 2896 } 2897 2898 Block = createBlock(false); 2899 Block->setTerminator(CFGTerminator(E, true)); 2900 2901 // See if this is a known constant. 2902 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2903 2904 if (LHSBlock) { 2905 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2906 } else if (KnownVal.isFalse()) { 2907 addSuccessor(Block, NULL); 2908 } else { 2909 addSuccessor(Block, ConfluenceBlock); 2910 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2911 } 2912 2913 if (!RHSBlock) 2914 RHSBlock = ConfluenceBlock; 2915 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2916 2917 return Block; 2918} 2919 2920} // end anonymous namespace 2921 2922/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2923/// no successors or predecessors. If this is the first block created in the 2924/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2925CFGBlock* CFG::createBlock() { 2926 bool first_block = begin() == end(); 2927 2928 // Create the block. 2929 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2930 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2931 Blocks.push_back(Mem, BlkBVC); 2932 2933 // If this is the first block, set it as the Entry and Exit. 2934 if (first_block) 2935 Entry = Exit = &back(); 2936 2937 // Return the block. 2938 return &back(); 2939} 2940 2941/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2942/// CFG is returned to the caller. 2943CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2944 const BuildOptions &BO) { 2945 CFGBuilder Builder(C, BO); 2946 return Builder.buildCFG(D, Statement); 2947} 2948 2949const CXXDestructorDecl * 2950CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 2951 switch (getKind()) { 2952 case CFGElement::Invalid: 2953 case CFGElement::Statement: 2954 case CFGElement::Initializer: 2955 llvm_unreachable("getDestructorDecl should only be used with " 2956 "ImplicitDtors"); 2957 case CFGElement::AutomaticObjectDtor: { 2958 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 2959 QualType ty = var->getType(); 2960 ty = ty.getNonReferenceType(); 2961 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 2962 ty = arrayType->getElementType(); 2963 } 2964 const RecordType *recordType = ty->getAs<RecordType>(); 2965 const CXXRecordDecl *classDecl = 2966 cast<CXXRecordDecl>(recordType->getDecl()); 2967 return classDecl->getDestructor(); 2968 } 2969 case CFGElement::TemporaryDtor: { 2970 const CXXBindTemporaryExpr *bindExpr = 2971 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 2972 const CXXTemporary *temp = bindExpr->getTemporary(); 2973 return temp->getDestructor(); 2974 } 2975 case CFGElement::BaseDtor: 2976 case CFGElement::MemberDtor: 2977 2978 // Not yet supported. 2979 return 0; 2980 } 2981 llvm_unreachable("getKind() returned bogus value"); 2982 return 0; 2983} 2984 2985bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 2986 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 2987 QualType ty = cdecl->getType(); 2988 return cast<FunctionType>(ty)->getNoReturnAttr(); 2989 } 2990 return false; 2991} 2992 2993//===----------------------------------------------------------------------===// 2994// CFG: Queries for BlkExprs. 2995//===----------------------------------------------------------------------===// 2996 2997namespace { 2998 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2999} 3000 3001static void FindSubExprAssignments(Stmt *S, 3002 llvm::SmallPtrSet<Expr*,50>& Set) { 3003 if (!S) 3004 return; 3005 3006 for (Stmt::child_range I = S->children(); I; ++I) { 3007 Stmt *child = *I; 3008 if (!child) 3009 continue; 3010 3011 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3012 if (B->isAssignmentOp()) Set.insert(B); 3013 3014 FindSubExprAssignments(child, Set); 3015 } 3016} 3017 3018static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3019 BlkExprMapTy* M = new BlkExprMapTy(); 3020 3021 // Look for assignments that are used as subexpressions. These are the only 3022 // assignments that we want to *possibly* register as a block-level 3023 // expression. Basically, if an assignment occurs both in a subexpression and 3024 // at the block-level, it is a block-level expression. 3025 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 3026 3027 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3028 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3029 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3030 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3031 3032 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3033 3034 // Iterate over the statements again on identify the Expr* and Stmt* at the 3035 // block-level that are block-level expressions. 3036 3037 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3038 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3039 if (!CS) 3040 continue; 3041 if (Expr* Exp = dyn_cast<Expr>(CS->getStmt())) { 3042 3043 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3044 // Assignment expressions that are not nested within another 3045 // expression are really "statements" whose value is never used by 3046 // another expression. 3047 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3048 continue; 3049 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 3050 // Special handling for statement expressions. The last statement in 3051 // the statement expression is also a block-level expr. 3052 const CompoundStmt* C = Terminator->getSubStmt(); 3053 if (!C->body_empty()) { 3054 unsigned x = M->size(); 3055 (*M)[C->body_back()] = x; 3056 } 3057 } 3058 3059 unsigned x = M->size(); 3060 (*M)[Exp] = x; 3061 } 3062 } 3063 3064 // Look at terminators. The condition is a block-level expression. 3065 3066 Stmt* S = (*I)->getTerminatorCondition(); 3067 3068 if (S && M->find(S) == M->end()) { 3069 unsigned x = M->size(); 3070 (*M)[S] = x; 3071 } 3072 } 3073 3074 return M; 3075} 3076 3077CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 3078 assert(S != NULL); 3079 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3080 3081 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3082 BlkExprMapTy::iterator I = M->find(S); 3083 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3084} 3085 3086unsigned CFG::getNumBlkExprs() { 3087 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3088 return M->size(); 3089 3090 // We assume callers interested in the number of BlkExprs will want 3091 // the map constructed if it doesn't already exist. 3092 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3093 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3094} 3095 3096//===----------------------------------------------------------------------===// 3097// Filtered walking of the CFG. 3098//===----------------------------------------------------------------------===// 3099 3100bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3101 const CFGBlock *From, const CFGBlock *To) { 3102 3103 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3104 // If the 'To' has no label or is labeled but the label isn't a 3105 // CaseStmt then filter this edge. 3106 if (const SwitchStmt *S = 3107 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3108 if (S->isAllEnumCasesCovered()) { 3109 const Stmt *L = To->getLabel(); 3110 if (!L || !isa<CaseStmt>(L)) 3111 return true; 3112 } 3113 } 3114 } 3115 3116 return false; 3117} 3118 3119//===----------------------------------------------------------------------===// 3120// Cleanup: CFG dstor. 3121//===----------------------------------------------------------------------===// 3122 3123CFG::~CFG() { 3124 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3125} 3126 3127//===----------------------------------------------------------------------===// 3128// CFG pretty printing 3129//===----------------------------------------------------------------------===// 3130 3131namespace { 3132 3133class StmtPrinterHelper : public PrinterHelper { 3134 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3135 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3136 StmtMapTy StmtMap; 3137 DeclMapTy DeclMap; 3138 signed currentBlock; 3139 unsigned currentStmt; 3140 const LangOptions &LangOpts; 3141public: 3142 3143 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3144 : currentBlock(0), currentStmt(0), LangOpts(LO) 3145 { 3146 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3147 unsigned j = 1; 3148 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3149 BI != BEnd; ++BI, ++j ) { 3150 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3151 const Stmt *stmt= SE->getStmt(); 3152 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3153 StmtMap[stmt] = P; 3154 3155 switch (stmt->getStmtClass()) { 3156 case Stmt::DeclStmtClass: 3157 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3158 break; 3159 case Stmt::IfStmtClass: { 3160 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3161 if (var) 3162 DeclMap[var] = P; 3163 break; 3164 } 3165 case Stmt::ForStmtClass: { 3166 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3167 if (var) 3168 DeclMap[var] = P; 3169 break; 3170 } 3171 case Stmt::WhileStmtClass: { 3172 const VarDecl *var = 3173 cast<WhileStmt>(stmt)->getConditionVariable(); 3174 if (var) 3175 DeclMap[var] = P; 3176 break; 3177 } 3178 case Stmt::SwitchStmtClass: { 3179 const VarDecl *var = 3180 cast<SwitchStmt>(stmt)->getConditionVariable(); 3181 if (var) 3182 DeclMap[var] = P; 3183 break; 3184 } 3185 case Stmt::CXXCatchStmtClass: { 3186 const VarDecl *var = 3187 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3188 if (var) 3189 DeclMap[var] = P; 3190 break; 3191 } 3192 default: 3193 break; 3194 } 3195 } 3196 } 3197 } 3198 } 3199 3200 3201 virtual ~StmtPrinterHelper() {} 3202 3203 const LangOptions &getLangOpts() const { return LangOpts; } 3204 void setBlockID(signed i) { currentBlock = i; } 3205 void setStmtID(unsigned i) { currentStmt = i; } 3206 3207 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 3208 StmtMapTy::iterator I = StmtMap.find(S); 3209 3210 if (I == StmtMap.end()) 3211 return false; 3212 3213 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3214 && I->second.second == currentStmt) { 3215 return false; 3216 } 3217 3218 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3219 return true; 3220 } 3221 3222 bool handleDecl(const Decl* D, llvm::raw_ostream& OS) { 3223 DeclMapTy::iterator I = DeclMap.find(D); 3224 3225 if (I == DeclMap.end()) 3226 return false; 3227 3228 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3229 && I->second.second == currentStmt) { 3230 return false; 3231 } 3232 3233 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3234 return true; 3235 } 3236}; 3237} // end anonymous namespace 3238 3239 3240namespace { 3241class CFGBlockTerminatorPrint 3242 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3243 3244 llvm::raw_ostream& OS; 3245 StmtPrinterHelper* Helper; 3246 PrintingPolicy Policy; 3247public: 3248 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 3249 const PrintingPolicy &Policy) 3250 : OS(os), Helper(helper), Policy(Policy) {} 3251 3252 void VisitIfStmt(IfStmt* I) { 3253 OS << "if "; 3254 I->getCond()->printPretty(OS,Helper,Policy); 3255 } 3256 3257 // Default case. 3258 void VisitStmt(Stmt* Terminator) { 3259 Terminator->printPretty(OS, Helper, Policy); 3260 } 3261 3262 void VisitForStmt(ForStmt* F) { 3263 OS << "for (" ; 3264 if (F->getInit()) 3265 OS << "..."; 3266 OS << "; "; 3267 if (Stmt* C = F->getCond()) 3268 C->printPretty(OS, Helper, Policy); 3269 OS << "; "; 3270 if (F->getInc()) 3271 OS << "..."; 3272 OS << ")"; 3273 } 3274 3275 void VisitWhileStmt(WhileStmt* W) { 3276 OS << "while " ; 3277 if (Stmt* C = W->getCond()) 3278 C->printPretty(OS, Helper, Policy); 3279 } 3280 3281 void VisitDoStmt(DoStmt* D) { 3282 OS << "do ... while "; 3283 if (Stmt* C = D->getCond()) 3284 C->printPretty(OS, Helper, Policy); 3285 } 3286 3287 void VisitSwitchStmt(SwitchStmt* Terminator) { 3288 OS << "switch "; 3289 Terminator->getCond()->printPretty(OS, Helper, Policy); 3290 } 3291 3292 void VisitCXXTryStmt(CXXTryStmt* CS) { 3293 OS << "try ..."; 3294 } 3295 3296 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3297 C->getCond()->printPretty(OS, Helper, Policy); 3298 OS << " ? ... : ..."; 3299 } 3300 3301 void VisitChooseExpr(ChooseExpr* C) { 3302 OS << "__builtin_choose_expr( "; 3303 C->getCond()->printPretty(OS, Helper, Policy); 3304 OS << " )"; 3305 } 3306 3307 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 3308 OS << "goto *"; 3309 I->getTarget()->printPretty(OS, Helper, Policy); 3310 } 3311 3312 void VisitBinaryOperator(BinaryOperator* B) { 3313 if (!B->isLogicalOp()) { 3314 VisitExpr(B); 3315 return; 3316 } 3317 3318 B->getLHS()->printPretty(OS, Helper, Policy); 3319 3320 switch (B->getOpcode()) { 3321 case BO_LOr: 3322 OS << " || ..."; 3323 return; 3324 case BO_LAnd: 3325 OS << " && ..."; 3326 return; 3327 default: 3328 assert(false && "Invalid logical operator."); 3329 } 3330 } 3331 3332 void VisitExpr(Expr* E) { 3333 E->printPretty(OS, Helper, Policy); 3334 } 3335}; 3336} // end anonymous namespace 3337 3338static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3339 const CFGElement &E) { 3340 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3341 Stmt *S = CS->getStmt(); 3342 3343 if (Helper) { 3344 3345 // special printing for statement-expressions. 3346 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3347 CompoundStmt* Sub = SE->getSubStmt(); 3348 3349 if (Sub->children()) { 3350 OS << "({ ... ; "; 3351 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3352 OS << " })\n"; 3353 return; 3354 } 3355 } 3356 // special printing for comma expressions. 3357 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3358 if (B->getOpcode() == BO_Comma) { 3359 OS << "... , "; 3360 Helper->handledStmt(B->getRHS(),OS); 3361 OS << '\n'; 3362 return; 3363 } 3364 } 3365 } 3366 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3367 3368 if (isa<CXXOperatorCallExpr>(S)) { 3369 OS << " (OperatorCall)"; 3370 } else if (isa<CXXBindTemporaryExpr>(S)) { 3371 OS << " (BindTemporary)"; 3372 } 3373 3374 // Expressions need a newline. 3375 if (isa<Expr>(S)) 3376 OS << '\n'; 3377 3378 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3379 const CXXCtorInitializer *I = IE->getInitializer(); 3380 if (I->isBaseInitializer()) 3381 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3382 else OS << I->getAnyMember()->getName(); 3383 3384 OS << "("; 3385 if (Expr* IE = I->getInit()) 3386 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3387 OS << ")"; 3388 3389 if (I->isBaseInitializer()) 3390 OS << " (Base initializer)\n"; 3391 else OS << " (Member initializer)\n"; 3392 3393 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3394 const VarDecl* VD = DE->getVarDecl(); 3395 Helper->handleDecl(VD, OS); 3396 3397 const Type* T = VD->getType().getTypePtr(); 3398 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3399 T = RT->getPointeeType().getTypePtr(); 3400 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3401 T = ET; 3402 3403 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3404 OS << " (Implicit destructor)\n"; 3405 3406 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3407 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3408 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3409 OS << " (Base object destructor)\n"; 3410 3411 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3412 const FieldDecl *FD = ME->getFieldDecl(); 3413 3414 const Type *T = FD->getType().getTypePtr(); 3415 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3416 T = ET; 3417 3418 OS << "this->" << FD->getName(); 3419 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3420 OS << " (Member object destructor)\n"; 3421 3422 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3423 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3424 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3425 OS << " (Temporary object destructor)\n"; 3426 } 3427} 3428 3429static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3430 const CFGBlock& B, 3431 StmtPrinterHelper* Helper, bool print_edges) { 3432 3433 if (Helper) Helper->setBlockID(B.getBlockID()); 3434 3435 // Print the header. 3436 OS << "\n [ B" << B.getBlockID(); 3437 3438 if (&B == &cfg->getEntry()) 3439 OS << " (ENTRY) ]\n"; 3440 else if (&B == &cfg->getExit()) 3441 OS << " (EXIT) ]\n"; 3442 else if (&B == cfg->getIndirectGotoBlock()) 3443 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3444 else 3445 OS << " ]\n"; 3446 3447 // Print the label of this block. 3448 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3449 3450 if (print_edges) 3451 OS << " "; 3452 3453 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3454 OS << L->getName(); 3455 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3456 OS << "case "; 3457 C->getLHS()->printPretty(OS, Helper, 3458 PrintingPolicy(Helper->getLangOpts())); 3459 if (C->getRHS()) { 3460 OS << " ... "; 3461 C->getRHS()->printPretty(OS, Helper, 3462 PrintingPolicy(Helper->getLangOpts())); 3463 } 3464 } else if (isa<DefaultStmt>(Label)) 3465 OS << "default"; 3466 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3467 OS << "catch ("; 3468 if (CS->getExceptionDecl()) 3469 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3470 0); 3471 else 3472 OS << "..."; 3473 OS << ")"; 3474 3475 } else 3476 assert(false && "Invalid label statement in CFGBlock."); 3477 3478 OS << ":\n"; 3479 } 3480 3481 // Iterate through the statements in the block and print them. 3482 unsigned j = 1; 3483 3484 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3485 I != E ; ++I, ++j ) { 3486 3487 // Print the statement # in the basic block and the statement itself. 3488 if (print_edges) 3489 OS << " "; 3490 3491 OS << llvm::format("%3d", j) << ": "; 3492 3493 if (Helper) 3494 Helper->setStmtID(j); 3495 3496 print_elem(OS,Helper,*I); 3497 } 3498 3499 // Print the terminator of this block. 3500 if (B.getTerminator()) { 3501 if (print_edges) 3502 OS << " "; 3503 3504 OS << " T: "; 3505 3506 if (Helper) Helper->setBlockID(-1); 3507 3508 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3509 PrintingPolicy(Helper->getLangOpts())); 3510 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3511 OS << '\n'; 3512 } 3513 3514 if (print_edges) { 3515 // Print the predecessors of this block. 3516 OS << " Predecessors (" << B.pred_size() << "):"; 3517 unsigned i = 0; 3518 3519 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3520 I != E; ++I, ++i) { 3521 3522 if (i == 8 || (i-8) == 0) 3523 OS << "\n "; 3524 3525 OS << " B" << (*I)->getBlockID(); 3526 } 3527 3528 OS << '\n'; 3529 3530 // Print the successors of this block. 3531 OS << " Successors (" << B.succ_size() << "):"; 3532 i = 0; 3533 3534 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3535 I != E; ++I, ++i) { 3536 3537 if (i == 8 || (i-8) % 10 == 0) 3538 OS << "\n "; 3539 3540 if (*I) 3541 OS << " B" << (*I)->getBlockID(); 3542 else 3543 OS << " NULL"; 3544 } 3545 3546 OS << '\n'; 3547 } 3548} 3549 3550 3551/// dump - A simple pretty printer of a CFG that outputs to stderr. 3552void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3553 3554/// print - A simple pretty printer of a CFG that outputs to an ostream. 3555void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3556 StmtPrinterHelper Helper(this, LO); 3557 3558 // Print the entry block. 3559 print_block(OS, this, getEntry(), &Helper, true); 3560 3561 // Iterate through the CFGBlocks and print them one by one. 3562 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3563 // Skip the entry block, because we already printed it. 3564 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3565 continue; 3566 3567 print_block(OS, this, **I, &Helper, true); 3568 } 3569 3570 // Print the exit block. 3571 print_block(OS, this, getExit(), &Helper, true); 3572 OS.flush(); 3573} 3574 3575/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3576void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3577 print(llvm::errs(), cfg, LO); 3578} 3579 3580/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3581/// Generally this will only be called from CFG::print. 3582void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3583 const LangOptions &LO) const { 3584 StmtPrinterHelper Helper(cfg, LO); 3585 print_block(OS, cfg, *this, &Helper, true); 3586} 3587 3588/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3589void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3590 const LangOptions &LO) const { 3591 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3592 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3593} 3594 3595Stmt* CFGBlock::getTerminatorCondition() { 3596 Stmt *Terminator = this->Terminator; 3597 if (!Terminator) 3598 return NULL; 3599 3600 Expr* E = NULL; 3601 3602 switch (Terminator->getStmtClass()) { 3603 default: 3604 break; 3605 3606 case Stmt::ForStmtClass: 3607 E = cast<ForStmt>(Terminator)->getCond(); 3608 break; 3609 3610 case Stmt::WhileStmtClass: 3611 E = cast<WhileStmt>(Terminator)->getCond(); 3612 break; 3613 3614 case Stmt::DoStmtClass: 3615 E = cast<DoStmt>(Terminator)->getCond(); 3616 break; 3617 3618 case Stmt::IfStmtClass: 3619 E = cast<IfStmt>(Terminator)->getCond(); 3620 break; 3621 3622 case Stmt::ChooseExprClass: 3623 E = cast<ChooseExpr>(Terminator)->getCond(); 3624 break; 3625 3626 case Stmt::IndirectGotoStmtClass: 3627 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3628 break; 3629 3630 case Stmt::SwitchStmtClass: 3631 E = cast<SwitchStmt>(Terminator)->getCond(); 3632 break; 3633 3634 case Stmt::BinaryConditionalOperatorClass: 3635 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3636 break; 3637 3638 case Stmt::ConditionalOperatorClass: 3639 E = cast<ConditionalOperator>(Terminator)->getCond(); 3640 break; 3641 3642 case Stmt::BinaryOperatorClass: // '&&' and '||' 3643 E = cast<BinaryOperator>(Terminator)->getLHS(); 3644 break; 3645 3646 case Stmt::ObjCForCollectionStmtClass: 3647 return Terminator; 3648 } 3649 3650 return E ? E->IgnoreParens() : NULL; 3651} 3652 3653//===----------------------------------------------------------------------===// 3654// CFG Graphviz Visualization 3655//===----------------------------------------------------------------------===// 3656 3657 3658#ifndef NDEBUG 3659static StmtPrinterHelper* GraphHelper; 3660#endif 3661 3662void CFG::viewCFG(const LangOptions &LO) const { 3663#ifndef NDEBUG 3664 StmtPrinterHelper H(this, LO); 3665 GraphHelper = &H; 3666 llvm::ViewGraph(this,"CFG"); 3667 GraphHelper = NULL; 3668#endif 3669} 3670 3671namespace llvm { 3672template<> 3673struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3674 3675 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3676 3677 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3678 3679#ifndef NDEBUG 3680 std::string OutSStr; 3681 llvm::raw_string_ostream Out(OutSStr); 3682 print_block(Out,Graph, *Node, GraphHelper, false); 3683 std::string& OutStr = Out.str(); 3684 3685 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3686 3687 // Process string output to make it nicer... 3688 for (unsigned i = 0; i != OutStr.length(); ++i) 3689 if (OutStr[i] == '\n') { // Left justify 3690 OutStr[i] = '\\'; 3691 OutStr.insert(OutStr.begin()+i+1, 'l'); 3692 } 3693 3694 return OutStr; 3695#else 3696 return ""; 3697#endif 3698 } 3699}; 3700} // end namespace llvm 3701