CFG.cpp revision 97078ec57e4a05e36840363a3a2926ac7d3d6003
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "clang/AST/CharUnits.h" 21#include "llvm/Support/GraphWriter.h" 22#include "llvm/Support/Allocator.h" 23#include "llvm/Support/Format.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/OwningPtr.h" 27 28using namespace clang; 29 30namespace { 31 32static SourceLocation GetEndLoc(Decl *D) { 33 if (VarDecl *VD = dyn_cast<VarDecl>(D)) 34 if (Expr *Ex = VD->getInit()) 35 return Ex->getSourceRange().getEnd(); 36 return D->getLocation(); 37} 38 39class CFGBuilder; 40 41/// The CFG builder uses a recursive algorithm to build the CFG. When 42/// we process an expression, sometimes we know that we must add the 43/// subexpressions as block-level expressions. For example: 44/// 45/// exp1 || exp2 46/// 47/// When processing the '||' expression, we know that exp1 and exp2 48/// need to be added as block-level expressions, even though they 49/// might not normally need to be. AddStmtChoice records this 50/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 51/// the builder has an option not to add a subexpression as a 52/// block-level expression. 53/// 54class AddStmtChoice { 55public: 56 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 57 58 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 59 60 bool alwaysAdd(CFGBuilder &builder, 61 const Stmt *stmt) const; 62 63 /// Return a copy of this object, except with the 'always-add' bit 64 /// set as specified. 65 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 66 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 67 } 68 69private: 70 Kind kind; 71}; 72 73/// LocalScope - Node in tree of local scopes created for C++ implicit 74/// destructor calls generation. It contains list of automatic variables 75/// declared in the scope and link to position in previous scope this scope 76/// began in. 77/// 78/// The process of creating local scopes is as follows: 79/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 80/// - Before processing statements in scope (e.g. CompoundStmt) create 81/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 82/// and set CFGBuilder::ScopePos to the end of new scope, 83/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 84/// at this VarDecl, 85/// - For every normal (without jump) end of scope add to CFGBlock destructors 86/// for objects in the current scope, 87/// - For every jump add to CFGBlock destructors for objects 88/// between CFGBuilder::ScopePos and local scope position saved for jump 89/// target. Thanks to C++ restrictions on goto jumps we can be sure that 90/// jump target position will be on the path to root from CFGBuilder::ScopePos 91/// (adding any variable that doesn't need constructor to be called to 92/// LocalScope can break this assumption), 93/// 94class LocalScope { 95public: 96 typedef BumpVector<VarDecl*> AutomaticVarsTy; 97 98 /// const_iterator - Iterates local scope backwards and jumps to previous 99 /// scope on reaching the beginning of currently iterated scope. 100 class const_iterator { 101 const LocalScope* Scope; 102 103 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 104 /// Invalid iterator (with null Scope) has VarIter equal to 0. 105 unsigned VarIter; 106 107 public: 108 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 109 /// Incrementing invalid iterator is allowed and will result in invalid 110 /// iterator. 111 const_iterator() 112 : Scope(NULL), VarIter(0) {} 113 114 /// Create valid iterator. In case when S.Prev is an invalid iterator and 115 /// I is equal to 0, this will create invalid iterator. 116 const_iterator(const LocalScope& S, unsigned I) 117 : Scope(&S), VarIter(I) { 118 // Iterator to "end" of scope is not allowed. Handle it by going up 119 // in scopes tree possibly up to invalid iterator in the root. 120 if (VarIter == 0 && Scope) 121 *this = Scope->Prev; 122 } 123 124 VarDecl *const* operator->() const { 125 assert (Scope && "Dereferencing invalid iterator is not allowed"); 126 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 127 return &Scope->Vars[VarIter - 1]; 128 } 129 VarDecl *operator*() const { 130 return *this->operator->(); 131 } 132 133 const_iterator &operator++() { 134 if (!Scope) 135 return *this; 136 137 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 138 --VarIter; 139 if (VarIter == 0) 140 *this = Scope->Prev; 141 return *this; 142 } 143 const_iterator operator++(int) { 144 const_iterator P = *this; 145 ++*this; 146 return P; 147 } 148 149 bool operator==(const const_iterator &rhs) const { 150 return Scope == rhs.Scope && VarIter == rhs.VarIter; 151 } 152 bool operator!=(const const_iterator &rhs) const { 153 return !(*this == rhs); 154 } 155 156 operator bool() const { 157 return *this != const_iterator(); 158 } 159 160 int distance(const_iterator L); 161 }; 162 163 friend class const_iterator; 164 165private: 166 BumpVectorContext ctx; 167 168 /// Automatic variables in order of declaration. 169 AutomaticVarsTy Vars; 170 /// Iterator to variable in previous scope that was declared just before 171 /// begin of this scope. 172 const_iterator Prev; 173 174public: 175 /// Constructs empty scope linked to previous scope in specified place. 176 LocalScope(BumpVectorContext &ctx, const_iterator P) 177 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 178 179 /// Begin of scope in direction of CFG building (backwards). 180 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 181 182 void addVar(VarDecl *VD) { 183 Vars.push_back(VD, ctx); 184 } 185}; 186 187/// distance - Calculates distance from this to L. L must be reachable from this 188/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 189/// number of scopes between this and L. 190int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 191 int D = 0; 192 const_iterator F = *this; 193 while (F.Scope != L.Scope) { 194 assert (F != const_iterator() 195 && "L iterator is not reachable from F iterator."); 196 D += F.VarIter; 197 F = F.Scope->Prev; 198 } 199 D += F.VarIter - L.VarIter; 200 return D; 201} 202 203/// BlockScopePosPair - Structure for specifying position in CFG during its 204/// build process. It consists of CFGBlock that specifies position in CFG graph 205/// and LocalScope::const_iterator that specifies position in LocalScope graph. 206struct BlockScopePosPair { 207 BlockScopePosPair() : block(0) {} 208 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos) 209 : block(b), scopePosition(scopePos) {} 210 211 CFGBlock *block; 212 LocalScope::const_iterator scopePosition; 213}; 214 215/// TryResult - a class representing a variant over the values 216/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 217/// and is used by the CFGBuilder to decide if a branch condition 218/// can be decided up front during CFG construction. 219class TryResult { 220 int X; 221public: 222 TryResult(bool b) : X(b ? 1 : 0) {} 223 TryResult() : X(-1) {} 224 225 bool isTrue() const { return X == 1; } 226 bool isFalse() const { return X == 0; } 227 bool isKnown() const { return X >= 0; } 228 void negate() { 229 assert(isKnown()); 230 X ^= 0x1; 231 } 232}; 233 234/// CFGBuilder - This class implements CFG construction from an AST. 235/// The builder is stateful: an instance of the builder should be used to only 236/// construct a single CFG. 237/// 238/// Example usage: 239/// 240/// CFGBuilder builder; 241/// CFG* cfg = builder.BuildAST(stmt1); 242/// 243/// CFG construction is done via a recursive walk of an AST. We actually parse 244/// the AST in reverse order so that the successor of a basic block is 245/// constructed prior to its predecessor. This allows us to nicely capture 246/// implicit fall-throughs without extra basic blocks. 247/// 248class CFGBuilder { 249 typedef BlockScopePosPair JumpTarget; 250 typedef BlockScopePosPair JumpSource; 251 252 ASTContext *Context; 253 llvm::OwningPtr<CFG> cfg; 254 255 CFGBlock *Block; 256 CFGBlock *Succ; 257 JumpTarget ContinueJumpTarget; 258 JumpTarget BreakJumpTarget; 259 CFGBlock *SwitchTerminatedBlock; 260 CFGBlock *DefaultCaseBlock; 261 CFGBlock *TryTerminatedBlock; 262 263 // Current position in local scope. 264 LocalScope::const_iterator ScopePos; 265 266 // LabelMap records the mapping from Label expressions to their jump targets. 267 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 268 LabelMapTy LabelMap; 269 270 // A list of blocks that end with a "goto" that must be backpatched to their 271 // resolved targets upon completion of CFG construction. 272 typedef std::vector<JumpSource> BackpatchBlocksTy; 273 BackpatchBlocksTy BackpatchBlocks; 274 275 // A list of labels whose address has been taken (for indirect gotos). 276 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 277 LabelSetTy AddressTakenLabels; 278 279 bool badCFG; 280 const CFG::BuildOptions &BuildOpts; 281 282 // State to track for building switch statements. 283 bool switchExclusivelyCovered; 284 Expr::EvalResult *switchCond; 285 286 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 287 const Stmt *lastLookup; 288 289public: 290 explicit CFGBuilder(ASTContext *astContext, 291 const CFG::BuildOptions &buildOpts) 292 : Context(astContext), cfg(new CFG()), // crew a new CFG 293 Block(NULL), Succ(NULL), 294 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 295 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 296 switchExclusivelyCovered(false), switchCond(0), 297 cachedEntry(0), lastLookup(0) {} 298 299 // buildCFG - Used by external clients to construct the CFG. 300 CFG* buildCFG(const Decl *D, Stmt *Statement); 301 302 bool alwaysAdd(const Stmt *stmt); 303 304private: 305 // Visitors to walk an AST and construct the CFG. 306 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 307 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 308 CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc); 309 CFGBlock *VisitBreakStmt(BreakStmt *B); 310 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 311 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 312 AddStmtChoice asc); 313 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 314 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 315 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 316 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 317 AddStmtChoice asc); 318 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 319 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 320 AddStmtChoice asc); 321 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 322 AddStmtChoice asc); 323 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 324 CFGBlock *VisitCaseStmt(CaseStmt *C); 325 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 326 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 327 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 328 AddStmtChoice asc); 329 CFGBlock *VisitContinueStmt(ContinueStmt *C); 330 CFGBlock *VisitDeclStmt(DeclStmt *DS); 331 CFGBlock *VisitDeclSubExpr(DeclStmt *DS); 332 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 333 CFGBlock *VisitDoStmt(DoStmt *D); 334 CFGBlock *VisitForStmt(ForStmt *F); 335 CFGBlock *VisitGotoStmt(GotoStmt *G); 336 CFGBlock *VisitIfStmt(IfStmt *I); 337 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 338 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 339 CFGBlock *VisitLabelStmt(LabelStmt *L); 340 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 341 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 342 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 343 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 344 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 345 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 346 CFGBlock *VisitReturnStmt(ReturnStmt *R); 347 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 348 AddStmtChoice asc); 349 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 350 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 351 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 352 CFGBlock *VisitWhileStmt(WhileStmt *W); 353 354 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 355 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 356 CFGBlock *VisitChildren(Stmt *S); 357 358 // Visitors to walk an AST and generate destructors of temporaries in 359 // full expression. 360 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 361 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 362 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 363 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 364 bool BindToTemporary); 365 CFGBlock * 366 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 367 bool BindToTemporary); 368 369 // NYS == Not Yet Supported 370 CFGBlock *NYS() { 371 badCFG = true; 372 return Block; 373 } 374 375 void autoCreateBlock() { if (!Block) Block = createBlock(); } 376 CFGBlock *createBlock(bool add_successor = true); 377 CFGBlock *createNoReturnBlock(); 378 379 CFGBlock *addStmt(Stmt *S) { 380 return Visit(S, AddStmtChoice::AlwaysAdd); 381 } 382 CFGBlock *addInitializer(CXXCtorInitializer *I); 383 void addAutomaticObjDtors(LocalScope::const_iterator B, 384 LocalScope::const_iterator E, Stmt *S); 385 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 386 387 // Local scopes creation. 388 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 389 390 void addLocalScopeForStmt(Stmt *S); 391 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 392 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 393 394 void addLocalScopeAndDtors(Stmt *S); 395 396 // Interface to CFGBlock - adding CFGElements. 397 void appendStmt(CFGBlock *B, const Stmt *S) { 398 if (alwaysAdd(S) && cachedEntry) 399 cachedEntry->second = B; 400 401 // All block-level expressions should have already been IgnoreParens()ed. 402 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 403 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 404 } 405 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 406 B->appendInitializer(I, cfg->getBumpVectorContext()); 407 } 408 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 409 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 410 } 411 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 412 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 413 } 414 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 415 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 416 } 417 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 418 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 419 } 420 421 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 422 LocalScope::const_iterator B, LocalScope::const_iterator E); 423 424 void addSuccessor(CFGBlock *B, CFGBlock *S) { 425 B->addSuccessor(S, cfg->getBumpVectorContext()); 426 } 427 428 /// Try and evaluate an expression to an integer constant. 429 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 430 if (!BuildOpts.PruneTriviallyFalseEdges) 431 return false; 432 return !S->isTypeDependent() && 433 !S->isValueDependent() && 434 S->EvaluateAsRValue(outResult, *Context); 435 } 436 437 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 438 /// if we can evaluate to a known value, otherwise return -1. 439 TryResult tryEvaluateBool(Expr *S) { 440 bool Result; 441 if (!BuildOpts.PruneTriviallyFalseEdges || 442 S->isTypeDependent() || S->isValueDependent() || 443 !S->EvaluateAsBooleanCondition(Result, *Context)) 444 return TryResult(); 445 return Result; 446 } 447 448}; 449 450inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 451 const Stmt *stmt) const { 452 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 453} 454 455bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 456 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 457 458 if (!BuildOpts.forcedBlkExprs) 459 return shouldAdd; 460 461 if (lastLookup == stmt) { 462 if (cachedEntry) { 463 assert(cachedEntry->first == stmt); 464 return true; 465 } 466 return shouldAdd; 467 } 468 469 lastLookup = stmt; 470 471 // Perform the lookup! 472 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 473 474 if (!fb) { 475 // No need to update 'cachedEntry', since it will always be null. 476 assert(cachedEntry == 0); 477 return shouldAdd; 478 } 479 480 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 481 if (itr == fb->end()) { 482 cachedEntry = 0; 483 return shouldAdd; 484 } 485 486 cachedEntry = &*itr; 487 return true; 488} 489 490// FIXME: Add support for dependent-sized array types in C++? 491// Does it even make sense to build a CFG for an uninstantiated template? 492static const VariableArrayType *FindVA(const Type *t) { 493 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 494 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 495 if (vat->getSizeExpr()) 496 return vat; 497 498 t = vt->getElementType().getTypePtr(); 499 } 500 501 return 0; 502} 503 504/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 505/// arbitrary statement. Examples include a single expression or a function 506/// body (compound statement). The ownership of the returned CFG is 507/// transferred to the caller. If CFG construction fails, this method returns 508/// NULL. 509CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 510 assert(cfg.get()); 511 if (!Statement) 512 return NULL; 513 514 // Create an empty block that will serve as the exit block for the CFG. Since 515 // this is the first block added to the CFG, it will be implicitly registered 516 // as the exit block. 517 Succ = createBlock(); 518 assert(Succ == &cfg->getExit()); 519 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 520 521 if (BuildOpts.AddImplicitDtors) 522 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 523 addImplicitDtorsForDestructor(DD); 524 525 // Visit the statements and create the CFG. 526 CFGBlock *B = addStmt(Statement); 527 528 if (badCFG) 529 return NULL; 530 531 // For C++ constructor add initializers to CFG. 532 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 533 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 534 E = CD->init_rend(); I != E; ++I) { 535 B = addInitializer(*I); 536 if (badCFG) 537 return NULL; 538 } 539 } 540 541 if (B) 542 Succ = B; 543 544 // Backpatch the gotos whose label -> block mappings we didn't know when we 545 // encountered them. 546 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 547 E = BackpatchBlocks.end(); I != E; ++I ) { 548 549 CFGBlock *B = I->block; 550 GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 551 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 552 553 // If there is no target for the goto, then we are looking at an 554 // incomplete AST. Handle this by not registering a successor. 555 if (LI == LabelMap.end()) continue; 556 557 JumpTarget JT = LI->second; 558 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 559 JT.scopePosition); 560 addSuccessor(B, JT.block); 561 } 562 563 // Add successors to the Indirect Goto Dispatch block (if we have one). 564 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 565 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 566 E = AddressTakenLabels.end(); I != E; ++I ) { 567 568 // Lookup the target block. 569 LabelMapTy::iterator LI = LabelMap.find(*I); 570 571 // If there is no target block that contains label, then we are looking 572 // at an incomplete AST. Handle this by not registering a successor. 573 if (LI == LabelMap.end()) continue; 574 575 addSuccessor(B, LI->second.block); 576 } 577 578 // Create an empty entry block that has no predecessors. 579 cfg->setEntry(createBlock()); 580 581 return cfg.take(); 582} 583 584/// createBlock - Used to lazily create blocks that are connected 585/// to the current (global) succcessor. 586CFGBlock *CFGBuilder::createBlock(bool add_successor) { 587 CFGBlock *B = cfg->createBlock(); 588 if (add_successor && Succ) 589 addSuccessor(B, Succ); 590 return B; 591} 592 593/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the 594/// CFG. It is *not* connected to the current (global) successor, and instead 595/// directly tied to the exit block in order to be reachable. 596CFGBlock *CFGBuilder::createNoReturnBlock() { 597 CFGBlock *B = createBlock(false); 598 B->setHasNoReturnElement(); 599 addSuccessor(B, &cfg->getExit()); 600 return B; 601} 602 603/// addInitializer - Add C++ base or member initializer element to CFG. 604CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 605 if (!BuildOpts.AddInitializers) 606 return Block; 607 608 bool IsReference = false; 609 bool HasTemporaries = false; 610 611 // Destructors of temporaries in initialization expression should be called 612 // after initialization finishes. 613 Expr *Init = I->getInit(); 614 if (Init) { 615 if (FieldDecl *FD = I->getAnyMember()) 616 IsReference = FD->getType()->isReferenceType(); 617 HasTemporaries = isa<ExprWithCleanups>(Init); 618 619 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 620 // Generate destructors for temporaries in initialization expression. 621 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 622 IsReference); 623 } 624 } 625 626 autoCreateBlock(); 627 appendInitializer(Block, I); 628 629 if (Init) { 630 if (HasTemporaries) { 631 // For expression with temporaries go directly to subexpression to omit 632 // generating destructors for the second time. 633 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 634 } 635 return Visit(Init); 636 } 637 638 return Block; 639} 640 641/// addAutomaticObjDtors - Add to current block automatic objects destructors 642/// for objects in range of local scope positions. Use S as trigger statement 643/// for destructors. 644void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 645 LocalScope::const_iterator E, Stmt *S) { 646 if (!BuildOpts.AddImplicitDtors) 647 return; 648 649 if (B == E) 650 return; 651 652 CFGBlock::iterator InsertPos; 653 654 // We need to append the destructors in reverse order, but any one of them 655 // may be a no-return destructor which changes the CFG. As a result, buffer 656 // this sequence up and replay them in reverse order when appending onto the 657 // CFGBlock(s). 658 SmallVector<VarDecl*, 10> Decls; 659 Decls.reserve(B.distance(E)); 660 for (LocalScope::const_iterator I = B; I != E; ++I) 661 Decls.push_back(*I); 662 663 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 664 E = Decls.rend(); 665 I != E; ++I) { 666 // If this destructor is marked as a no-return destructor, we need to 667 // create a new block for the destructor which does not have as a successor 668 // anything built thus far: control won't flow out of this block. 669 QualType Ty = (*I)->getType().getNonReferenceType(); 670 if (const ArrayType *AT = Context->getAsArrayType(Ty)) 671 Ty = AT->getElementType(); 672 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 673 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 674 Block = createNoReturnBlock(); 675 else 676 autoCreateBlock(); 677 678 appendAutomaticObjDtor(Block, *I, S); 679 } 680} 681 682/// addImplicitDtorsForDestructor - Add implicit destructors generated for 683/// base and member objects in destructor. 684void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 685 assert (BuildOpts.AddImplicitDtors 686 && "Can be called only when dtors should be added"); 687 const CXXRecordDecl *RD = DD->getParent(); 688 689 // At the end destroy virtual base objects. 690 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 691 VE = RD->vbases_end(); VI != VE; ++VI) { 692 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 693 if (!CD->hasTrivialDestructor()) { 694 autoCreateBlock(); 695 appendBaseDtor(Block, VI); 696 } 697 } 698 699 // Before virtual bases destroy direct base objects. 700 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 701 BE = RD->bases_end(); BI != BE; ++BI) { 702 if (!BI->isVirtual()) { 703 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 704 if (!CD->hasTrivialDestructor()) { 705 autoCreateBlock(); 706 appendBaseDtor(Block, BI); 707 } 708 } 709 } 710 711 // First destroy member objects. 712 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 713 FE = RD->field_end(); FI != FE; ++FI) { 714 // Check for constant size array. Set type to array element type. 715 QualType QT = FI->getType(); 716 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 717 if (AT->getSize() == 0) 718 continue; 719 QT = AT->getElementType(); 720 } 721 722 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 723 if (!CD->hasTrivialDestructor()) { 724 autoCreateBlock(); 725 appendMemberDtor(Block, *FI); 726 } 727 } 728} 729 730/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 731/// way return valid LocalScope object. 732LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 733 if (!Scope) { 734 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 735 Scope = alloc.Allocate<LocalScope>(); 736 BumpVectorContext ctx(alloc); 737 new (Scope) LocalScope(ctx, ScopePos); 738 } 739 return Scope; 740} 741 742/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 743/// that should create implicit scope (e.g. if/else substatements). 744void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 745 if (!BuildOpts.AddImplicitDtors) 746 return; 747 748 LocalScope *Scope = 0; 749 750 // For compound statement we will be creating explicit scope. 751 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 752 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 753 ; BI != BE; ++BI) { 754 Stmt *SI = (*BI)->stripLabelLikeStatements(); 755 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 756 Scope = addLocalScopeForDeclStmt(DS, Scope); 757 } 758 return; 759 } 760 761 // For any other statement scope will be implicit and as such will be 762 // interesting only for DeclStmt. 763 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 764 addLocalScopeForDeclStmt(DS); 765} 766 767/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 768/// reuse Scope if not NULL. 769LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 770 LocalScope* Scope) { 771 if (!BuildOpts.AddImplicitDtors) 772 return Scope; 773 774 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 775 ; DI != DE; ++DI) { 776 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 777 Scope = addLocalScopeForVarDecl(VD, Scope); 778 } 779 return Scope; 780} 781 782/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 783/// create add scope for automatic objects and temporary objects bound to 784/// const reference. Will reuse Scope if not NULL. 785LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 786 LocalScope* Scope) { 787 if (!BuildOpts.AddImplicitDtors) 788 return Scope; 789 790 // Check if variable is local. 791 switch (VD->getStorageClass()) { 792 case SC_None: 793 case SC_Auto: 794 case SC_Register: 795 break; 796 default: return Scope; 797 } 798 799 // Check for const references bound to temporary. Set type to pointee. 800 QualType QT = VD->getType(); 801 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 802 QT = RT->getPointeeType(); 803 if (!QT.isConstQualified()) 804 return Scope; 805 if (!VD->extendsLifetimeOfTemporary()) 806 return Scope; 807 } 808 809 // Check for constant size array. Set type to array element type. 810 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 811 if (AT->getSize() == 0) 812 return Scope; 813 QT = AT->getElementType(); 814 } 815 816 // Check if type is a C++ class with non-trivial destructor. 817 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 818 if (!CD->hasTrivialDestructor()) { 819 // Add the variable to scope 820 Scope = createOrReuseLocalScope(Scope); 821 Scope->addVar(VD); 822 ScopePos = Scope->begin(); 823 } 824 return Scope; 825} 826 827/// addLocalScopeAndDtors - For given statement add local scope for it and 828/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 829void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 830 if (!BuildOpts.AddImplicitDtors) 831 return; 832 833 LocalScope::const_iterator scopeBeginPos = ScopePos; 834 addLocalScopeForStmt(S); 835 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 836} 837 838/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 839/// variables with automatic storage duration to CFGBlock's elements vector. 840/// Elements will be prepended to physical beginning of the vector which 841/// happens to be logical end. Use blocks terminator as statement that specifies 842/// destructors call site. 843/// FIXME: This mechanism for adding automatic destructors doesn't handle 844/// no-return destructors properly. 845void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 846 LocalScope::const_iterator B, LocalScope::const_iterator E) { 847 BumpVectorContext &C = cfg->getBumpVectorContext(); 848 CFGBlock::iterator InsertPos 849 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 850 for (LocalScope::const_iterator I = B; I != E; ++I) 851 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 852 Blk->getTerminator()); 853} 854 855/// Visit - Walk the subtree of a statement and add extra 856/// blocks for ternary operators, &&, and ||. We also process "," and 857/// DeclStmts (which may contain nested control-flow). 858CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 859 if (!S) { 860 badCFG = true; 861 return 0; 862 } 863 864 if (Expr *E = dyn_cast<Expr>(S)) 865 S = E->IgnoreParens(); 866 867 switch (S->getStmtClass()) { 868 default: 869 return VisitStmt(S, asc); 870 871 case Stmt::AddrLabelExprClass: 872 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 873 874 case Stmt::BinaryConditionalOperatorClass: 875 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 876 877 case Stmt::BinaryOperatorClass: 878 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 879 880 case Stmt::BlockExprClass: 881 return VisitBlockExpr(cast<BlockExpr>(S), asc); 882 883 case Stmt::BreakStmtClass: 884 return VisitBreakStmt(cast<BreakStmt>(S)); 885 886 case Stmt::CallExprClass: 887 case Stmt::CXXOperatorCallExprClass: 888 case Stmt::CXXMemberCallExprClass: 889 return VisitCallExpr(cast<CallExpr>(S), asc); 890 891 case Stmt::CaseStmtClass: 892 return VisitCaseStmt(cast<CaseStmt>(S)); 893 894 case Stmt::ChooseExprClass: 895 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 896 897 case Stmt::CompoundStmtClass: 898 return VisitCompoundStmt(cast<CompoundStmt>(S)); 899 900 case Stmt::ConditionalOperatorClass: 901 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 902 903 case Stmt::ContinueStmtClass: 904 return VisitContinueStmt(cast<ContinueStmt>(S)); 905 906 case Stmt::CXXCatchStmtClass: 907 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 908 909 case Stmt::ExprWithCleanupsClass: 910 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 911 912 case Stmt::CXXBindTemporaryExprClass: 913 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 914 915 case Stmt::CXXConstructExprClass: 916 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 917 918 case Stmt::CXXFunctionalCastExprClass: 919 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 920 921 case Stmt::CXXTemporaryObjectExprClass: 922 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 923 924 case Stmt::CXXThrowExprClass: 925 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 926 927 case Stmt::CXXTryStmtClass: 928 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 929 930 case Stmt::CXXForRangeStmtClass: 931 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 932 933 case Stmt::DeclStmtClass: 934 return VisitDeclStmt(cast<DeclStmt>(S)); 935 936 case Stmt::DefaultStmtClass: 937 return VisitDefaultStmt(cast<DefaultStmt>(S)); 938 939 case Stmt::DoStmtClass: 940 return VisitDoStmt(cast<DoStmt>(S)); 941 942 case Stmt::ForStmtClass: 943 return VisitForStmt(cast<ForStmt>(S)); 944 945 case Stmt::GotoStmtClass: 946 return VisitGotoStmt(cast<GotoStmt>(S)); 947 948 case Stmt::IfStmtClass: 949 return VisitIfStmt(cast<IfStmt>(S)); 950 951 case Stmt::ImplicitCastExprClass: 952 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 953 954 case Stmt::IndirectGotoStmtClass: 955 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 956 957 case Stmt::LabelStmtClass: 958 return VisitLabelStmt(cast<LabelStmt>(S)); 959 960 case Stmt::MemberExprClass: 961 return VisitMemberExpr(cast<MemberExpr>(S), asc); 962 963 case Stmt::NullStmtClass: 964 return Block; 965 966 case Stmt::ObjCAtCatchStmtClass: 967 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 968 969 case Stmt::ObjCAtSynchronizedStmtClass: 970 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 971 972 case Stmt::ObjCAtThrowStmtClass: 973 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 974 975 case Stmt::ObjCAtTryStmtClass: 976 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 977 978 case Stmt::ObjCForCollectionStmtClass: 979 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 980 981 case Stmt::OpaqueValueExprClass: 982 return Block; 983 984 case Stmt::ReturnStmtClass: 985 return VisitReturnStmt(cast<ReturnStmt>(S)); 986 987 case Stmt::UnaryExprOrTypeTraitExprClass: 988 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 989 asc); 990 991 case Stmt::StmtExprClass: 992 return VisitStmtExpr(cast<StmtExpr>(S), asc); 993 994 case Stmt::SwitchStmtClass: 995 return VisitSwitchStmt(cast<SwitchStmt>(S)); 996 997 case Stmt::UnaryOperatorClass: 998 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 999 1000 case Stmt::WhileStmtClass: 1001 return VisitWhileStmt(cast<WhileStmt>(S)); 1002 } 1003} 1004 1005CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1006 if (asc.alwaysAdd(*this, S)) { 1007 autoCreateBlock(); 1008 appendStmt(Block, S); 1009 } 1010 1011 return VisitChildren(S); 1012} 1013 1014/// VisitChildren - Visit the children of a Stmt. 1015CFGBlock *CFGBuilder::VisitChildren(Stmt *Terminator) { 1016 CFGBlock *lastBlock = Block; 1017 for (Stmt::child_range I = Terminator->children(); I; ++I) 1018 if (Stmt *child = *I) 1019 if (CFGBlock *b = Visit(child)) 1020 lastBlock = b; 1021 1022 return lastBlock; 1023} 1024 1025CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1026 AddStmtChoice asc) { 1027 AddressTakenLabels.insert(A->getLabel()); 1028 1029 if (asc.alwaysAdd(*this, A)) { 1030 autoCreateBlock(); 1031 appendStmt(Block, A); 1032 } 1033 1034 return Block; 1035} 1036 1037CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1038 AddStmtChoice asc) { 1039 if (asc.alwaysAdd(*this, U)) { 1040 autoCreateBlock(); 1041 appendStmt(Block, U); 1042 } 1043 1044 return Visit(U->getSubExpr(), AddStmtChoice()); 1045} 1046 1047CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1048 AddStmtChoice asc) { 1049 if (B->isLogicalOp()) { // && or || 1050 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1051 appendStmt(ConfluenceBlock, B); 1052 1053 if (badCFG) 1054 return 0; 1055 1056 // create the block evaluating the LHS 1057 CFGBlock *LHSBlock = createBlock(false); 1058 LHSBlock->setTerminator(B); 1059 1060 // create the block evaluating the RHS 1061 Succ = ConfluenceBlock; 1062 Block = NULL; 1063 CFGBlock *RHSBlock = addStmt(B->getRHS()); 1064 1065 if (RHSBlock) { 1066 if (badCFG) 1067 return 0; 1068 } else { 1069 // Create an empty block for cases where the RHS doesn't require 1070 // any explicit statements in the CFG. 1071 RHSBlock = createBlock(); 1072 } 1073 1074 // See if this is a known constant. 1075 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1076 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1077 KnownVal.negate(); 1078 1079 // Now link the LHSBlock with RHSBlock. 1080 if (B->getOpcode() == BO_LOr) { 1081 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1082 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1083 } else { 1084 assert(B->getOpcode() == BO_LAnd); 1085 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1086 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1087 } 1088 1089 // Generate the blocks for evaluating the LHS. 1090 Block = LHSBlock; 1091 return addStmt(B->getLHS()); 1092 } 1093 1094 if (B->getOpcode() == BO_Comma) { // , 1095 autoCreateBlock(); 1096 appendStmt(Block, B); 1097 addStmt(B->getRHS()); 1098 return addStmt(B->getLHS()); 1099 } 1100 1101 if (B->isAssignmentOp()) { 1102 if (asc.alwaysAdd(*this, B)) { 1103 autoCreateBlock(); 1104 appendStmt(Block, B); 1105 } 1106 Visit(B->getLHS()); 1107 return Visit(B->getRHS()); 1108 } 1109 1110 if (asc.alwaysAdd(*this, B)) { 1111 autoCreateBlock(); 1112 appendStmt(Block, B); 1113 } 1114 1115 CFGBlock *RBlock = Visit(B->getRHS()); 1116 CFGBlock *LBlock = Visit(B->getLHS()); 1117 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1118 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1119 // return RBlock. Otherwise we'll incorrectly return NULL. 1120 return (LBlock ? LBlock : RBlock); 1121} 1122 1123CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1124 if (asc.alwaysAdd(*this, E)) { 1125 autoCreateBlock(); 1126 appendStmt(Block, E); 1127 } 1128 return Block; 1129} 1130 1131CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1132 // "break" is a control-flow statement. Thus we stop processing the current 1133 // block. 1134 if (badCFG) 1135 return 0; 1136 1137 // Now create a new block that ends with the break statement. 1138 Block = createBlock(false); 1139 Block->setTerminator(B); 1140 1141 // If there is no target for the break, then we are looking at an incomplete 1142 // AST. This means that the CFG cannot be constructed. 1143 if (BreakJumpTarget.block) { 1144 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1145 addSuccessor(Block, BreakJumpTarget.block); 1146 } else 1147 badCFG = true; 1148 1149 1150 return Block; 1151} 1152 1153static bool CanThrow(Expr *E, ASTContext &Ctx) { 1154 QualType Ty = E->getType(); 1155 if (Ty->isFunctionPointerType()) 1156 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1157 else if (Ty->isBlockPointerType()) 1158 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1159 1160 const FunctionType *FT = Ty->getAs<FunctionType>(); 1161 if (FT) { 1162 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1163 if (Proto->isNothrow(Ctx)) 1164 return false; 1165 } 1166 return true; 1167} 1168 1169CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1170 // Compute the callee type. 1171 QualType calleeType = C->getCallee()->getType(); 1172 if (calleeType == Context->BoundMemberTy) { 1173 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1174 1175 // We should only get a null bound type if processing a dependent 1176 // CFG. Recover by assuming nothing. 1177 if (!boundType.isNull()) calleeType = boundType; 1178 } 1179 1180 // If this is a call to a no-return function, this stops the block here. 1181 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1182 1183 bool AddEHEdge = false; 1184 1185 // Languages without exceptions are assumed to not throw. 1186 if (Context->getLangOptions().Exceptions) { 1187 if (BuildOpts.AddEHEdges) 1188 AddEHEdge = true; 1189 } 1190 1191 if (FunctionDecl *FD = C->getDirectCallee()) { 1192 if (FD->hasAttr<NoReturnAttr>()) 1193 NoReturn = true; 1194 if (FD->hasAttr<NoThrowAttr>()) 1195 AddEHEdge = false; 1196 } 1197 1198 if (!CanThrow(C->getCallee(), *Context)) 1199 AddEHEdge = false; 1200 1201 if (!NoReturn && !AddEHEdge) 1202 return VisitStmt(C, asc.withAlwaysAdd(true)); 1203 1204 if (Block) { 1205 Succ = Block; 1206 if (badCFG) 1207 return 0; 1208 } 1209 1210 if (NoReturn) 1211 Block = createNoReturnBlock(); 1212 else 1213 Block = createBlock(); 1214 1215 appendStmt(Block, C); 1216 1217 if (AddEHEdge) { 1218 // Add exceptional edges. 1219 if (TryTerminatedBlock) 1220 addSuccessor(Block, TryTerminatedBlock); 1221 else 1222 addSuccessor(Block, &cfg->getExit()); 1223 } 1224 1225 return VisitChildren(C); 1226} 1227 1228CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1229 AddStmtChoice asc) { 1230 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1231 appendStmt(ConfluenceBlock, C); 1232 if (badCFG) 1233 return 0; 1234 1235 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1236 Succ = ConfluenceBlock; 1237 Block = NULL; 1238 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1239 if (badCFG) 1240 return 0; 1241 1242 Succ = ConfluenceBlock; 1243 Block = NULL; 1244 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1245 if (badCFG) 1246 return 0; 1247 1248 Block = createBlock(false); 1249 // See if this is a known constant. 1250 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1251 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1252 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1253 Block->setTerminator(C); 1254 return addStmt(C->getCond()); 1255} 1256 1257 1258CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1259 addLocalScopeAndDtors(C); 1260 CFGBlock *LastBlock = Block; 1261 1262 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1263 I != E; ++I ) { 1264 // If we hit a segment of code just containing ';' (NullStmts), we can 1265 // get a null block back. In such cases, just use the LastBlock 1266 if (CFGBlock *newBlock = addStmt(*I)) 1267 LastBlock = newBlock; 1268 1269 if (badCFG) 1270 return NULL; 1271 } 1272 1273 return LastBlock; 1274} 1275 1276CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1277 AddStmtChoice asc) { 1278 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1279 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1280 1281 // Create the confluence block that will "merge" the results of the ternary 1282 // expression. 1283 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1284 appendStmt(ConfluenceBlock, C); 1285 if (badCFG) 1286 return 0; 1287 1288 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1289 1290 // Create a block for the LHS expression if there is an LHS expression. A 1291 // GCC extension allows LHS to be NULL, causing the condition to be the 1292 // value that is returned instead. 1293 // e.g: x ?: y is shorthand for: x ? x : y; 1294 Succ = ConfluenceBlock; 1295 Block = NULL; 1296 CFGBlock *LHSBlock = 0; 1297 const Expr *trueExpr = C->getTrueExpr(); 1298 if (trueExpr != opaqueValue) { 1299 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1300 if (badCFG) 1301 return 0; 1302 Block = NULL; 1303 } 1304 else 1305 LHSBlock = ConfluenceBlock; 1306 1307 // Create the block for the RHS expression. 1308 Succ = ConfluenceBlock; 1309 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1310 if (badCFG) 1311 return 0; 1312 1313 // Create the block that will contain the condition. 1314 Block = createBlock(false); 1315 1316 // See if this is a known constant. 1317 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1318 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1319 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1320 Block->setTerminator(C); 1321 Expr *condExpr = C->getCond(); 1322 1323 if (opaqueValue) { 1324 // Run the condition expression if it's not trivially expressed in 1325 // terms of the opaque value (or if there is no opaque value). 1326 if (condExpr != opaqueValue) 1327 addStmt(condExpr); 1328 1329 // Before that, run the common subexpression if there was one. 1330 // At least one of this or the above will be run. 1331 return addStmt(BCO->getCommon()); 1332 } 1333 1334 return addStmt(condExpr); 1335} 1336 1337CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1338 // Check if the Decl is for an __label__. If so, elide it from the 1339 // CFG entirely. 1340 if (isa<LabelDecl>(*DS->decl_begin())) 1341 return Block; 1342 1343 // This case also handles static_asserts. 1344 if (DS->isSingleDecl()) 1345 return VisitDeclSubExpr(DS); 1346 1347 CFGBlock *B = 0; 1348 1349 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1350 typedef SmallVector<Decl*,10> BufTy; 1351 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1352 1353 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1354 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1355 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1356 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1357 1358 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1359 // automatically freed with the CFG. 1360 DeclGroupRef DG(*I); 1361 Decl *D = *I; 1362 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1363 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1364 1365 // Append the fake DeclStmt to block. 1366 B = VisitDeclSubExpr(DSNew); 1367 } 1368 1369 return B; 1370} 1371 1372/// VisitDeclSubExpr - Utility method to add block-level expressions for 1373/// DeclStmts and initializers in them. 1374CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1375 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1376 Decl *D = DS->getSingleDecl(); 1377 1378 if (isa<StaticAssertDecl>(D)) { 1379 // static_asserts aren't added to the CFG because they do not impact 1380 // runtime semantics. 1381 return Block; 1382 } 1383 1384 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1385 1386 if (!VD) { 1387 autoCreateBlock(); 1388 appendStmt(Block, DS); 1389 return Block; 1390 } 1391 1392 bool IsReference = false; 1393 bool HasTemporaries = false; 1394 1395 // Destructors of temporaries in initialization expression should be called 1396 // after initialization finishes. 1397 Expr *Init = VD->getInit(); 1398 if (Init) { 1399 IsReference = VD->getType()->isReferenceType(); 1400 HasTemporaries = isa<ExprWithCleanups>(Init); 1401 1402 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1403 // Generate destructors for temporaries in initialization expression. 1404 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1405 IsReference); 1406 } 1407 } 1408 1409 autoCreateBlock(); 1410 appendStmt(Block, DS); 1411 1412 if (Init) { 1413 if (HasTemporaries) 1414 // For expression with temporaries go directly to subexpression to omit 1415 // generating destructors for the second time. 1416 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1417 else 1418 Visit(Init); 1419 } 1420 1421 // If the type of VD is a VLA, then we must process its size expressions. 1422 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1423 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1424 Block = addStmt(VA->getSizeExpr()); 1425 1426 // Remove variable from local scope. 1427 if (ScopePos && VD == *ScopePos) 1428 ++ScopePos; 1429 1430 return Block; 1431} 1432 1433CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1434 // We may see an if statement in the middle of a basic block, or it may be the 1435 // first statement we are processing. In either case, we create a new basic 1436 // block. First, we create the blocks for the then...else statements, and 1437 // then we create the block containing the if statement. If we were in the 1438 // middle of a block, we stop processing that block. That block is then the 1439 // implicit successor for the "then" and "else" clauses. 1440 1441 // Save local scope position because in case of condition variable ScopePos 1442 // won't be restored when traversing AST. 1443 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1444 1445 // Create local scope for possible condition variable. 1446 // Store scope position. Add implicit destructor. 1447 if (VarDecl *VD = I->getConditionVariable()) { 1448 LocalScope::const_iterator BeginScopePos = ScopePos; 1449 addLocalScopeForVarDecl(VD); 1450 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1451 } 1452 1453 // The block we were processing is now finished. Make it the successor 1454 // block. 1455 if (Block) { 1456 Succ = Block; 1457 if (badCFG) 1458 return 0; 1459 } 1460 1461 // Process the false branch. 1462 CFGBlock *ElseBlock = Succ; 1463 1464 if (Stmt *Else = I->getElse()) { 1465 SaveAndRestore<CFGBlock*> sv(Succ); 1466 1467 // NULL out Block so that the recursive call to Visit will 1468 // create a new basic block. 1469 Block = NULL; 1470 1471 // If branch is not a compound statement create implicit scope 1472 // and add destructors. 1473 if (!isa<CompoundStmt>(Else)) 1474 addLocalScopeAndDtors(Else); 1475 1476 ElseBlock = addStmt(Else); 1477 1478 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1479 ElseBlock = sv.get(); 1480 else if (Block) { 1481 if (badCFG) 1482 return 0; 1483 } 1484 } 1485 1486 // Process the true branch. 1487 CFGBlock *ThenBlock; 1488 { 1489 Stmt *Then = I->getThen(); 1490 assert(Then); 1491 SaveAndRestore<CFGBlock*> sv(Succ); 1492 Block = NULL; 1493 1494 // If branch is not a compound statement create implicit scope 1495 // and add destructors. 1496 if (!isa<CompoundStmt>(Then)) 1497 addLocalScopeAndDtors(Then); 1498 1499 ThenBlock = addStmt(Then); 1500 1501 if (!ThenBlock) { 1502 // We can reach here if the "then" body has all NullStmts. 1503 // Create an empty block so we can distinguish between true and false 1504 // branches in path-sensitive analyses. 1505 ThenBlock = createBlock(false); 1506 addSuccessor(ThenBlock, sv.get()); 1507 } else if (Block) { 1508 if (badCFG) 1509 return 0; 1510 } 1511 } 1512 1513 // Now create a new block containing the if statement. 1514 Block = createBlock(false); 1515 1516 // Set the terminator of the new block to the If statement. 1517 Block->setTerminator(I); 1518 1519 // See if this is a known constant. 1520 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1521 1522 // Now add the successors. 1523 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1524 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1525 1526 // Add the condition as the last statement in the new block. This may create 1527 // new blocks as the condition may contain control-flow. Any newly created 1528 // blocks will be pointed to be "Block". 1529 Block = addStmt(I->getCond()); 1530 1531 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1532 // and the condition variable initialization to the CFG. 1533 if (VarDecl *VD = I->getConditionVariable()) { 1534 if (Expr *Init = VD->getInit()) { 1535 autoCreateBlock(); 1536 appendStmt(Block, I->getConditionVariableDeclStmt()); 1537 addStmt(Init); 1538 } 1539 } 1540 1541 return Block; 1542} 1543 1544 1545CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1546 // If we were in the middle of a block we stop processing that block. 1547 // 1548 // NOTE: If a "return" appears in the middle of a block, this means that the 1549 // code afterwards is DEAD (unreachable). We still keep a basic block 1550 // for that code; a simple "mark-and-sweep" from the entry block will be 1551 // able to report such dead blocks. 1552 1553 // Create the new block. 1554 Block = createBlock(false); 1555 1556 // The Exit block is the only successor. 1557 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1558 addSuccessor(Block, &cfg->getExit()); 1559 1560 // Add the return statement to the block. This may create new blocks if R 1561 // contains control-flow (short-circuit operations). 1562 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1563} 1564 1565CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1566 // Get the block of the labeled statement. Add it to our map. 1567 addStmt(L->getSubStmt()); 1568 CFGBlock *LabelBlock = Block; 1569 1570 if (!LabelBlock) // This can happen when the body is empty, i.e. 1571 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1572 1573 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1574 "label already in map"); 1575 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1576 1577 // Labels partition blocks, so this is the end of the basic block we were 1578 // processing (L is the block's label). Because this is label (and we have 1579 // already processed the substatement) there is no extra control-flow to worry 1580 // about. 1581 LabelBlock->setLabel(L); 1582 if (badCFG) 1583 return 0; 1584 1585 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1586 Block = NULL; 1587 1588 // This block is now the implicit successor of other blocks. 1589 Succ = LabelBlock; 1590 1591 return LabelBlock; 1592} 1593 1594CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1595 // Goto is a control-flow statement. Thus we stop processing the current 1596 // block and create a new one. 1597 1598 Block = createBlock(false); 1599 Block->setTerminator(G); 1600 1601 // If we already know the mapping to the label block add the successor now. 1602 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1603 1604 if (I == LabelMap.end()) 1605 // We will need to backpatch this block later. 1606 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1607 else { 1608 JumpTarget JT = I->second; 1609 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1610 addSuccessor(Block, JT.block); 1611 } 1612 1613 return Block; 1614} 1615 1616CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1617 CFGBlock *LoopSuccessor = NULL; 1618 1619 // Save local scope position because in case of condition variable ScopePos 1620 // won't be restored when traversing AST. 1621 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1622 1623 // Create local scope for init statement and possible condition variable. 1624 // Add destructor for init statement and condition variable. 1625 // Store scope position for continue statement. 1626 if (Stmt *Init = F->getInit()) 1627 addLocalScopeForStmt(Init); 1628 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1629 1630 if (VarDecl *VD = F->getConditionVariable()) 1631 addLocalScopeForVarDecl(VD); 1632 LocalScope::const_iterator ContinueScopePos = ScopePos; 1633 1634 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1635 1636 // "for" is a control-flow statement. Thus we stop processing the current 1637 // block. 1638 if (Block) { 1639 if (badCFG) 1640 return 0; 1641 LoopSuccessor = Block; 1642 } else 1643 LoopSuccessor = Succ; 1644 1645 // Save the current value for the break targets. 1646 // All breaks should go to the code following the loop. 1647 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1648 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1649 1650 // Because of short-circuit evaluation, the condition of the loop can span 1651 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1652 // evaluate the condition. 1653 CFGBlock *ExitConditionBlock = createBlock(false); 1654 CFGBlock *EntryConditionBlock = ExitConditionBlock; 1655 1656 // Set the terminator for the "exit" condition block. 1657 ExitConditionBlock->setTerminator(F); 1658 1659 // Now add the actual condition to the condition block. Because the condition 1660 // itself may contain control-flow, new blocks may be created. 1661 if (Stmt *C = F->getCond()) { 1662 Block = ExitConditionBlock; 1663 EntryConditionBlock = addStmt(C); 1664 if (badCFG) 1665 return 0; 1666 assert(Block == EntryConditionBlock || 1667 (Block == 0 && EntryConditionBlock == Succ)); 1668 1669 // If this block contains a condition variable, add both the condition 1670 // variable and initializer to the CFG. 1671 if (VarDecl *VD = F->getConditionVariable()) { 1672 if (Expr *Init = VD->getInit()) { 1673 autoCreateBlock(); 1674 appendStmt(Block, F->getConditionVariableDeclStmt()); 1675 EntryConditionBlock = addStmt(Init); 1676 assert(Block == EntryConditionBlock); 1677 } 1678 } 1679 1680 if (Block) { 1681 if (badCFG) 1682 return 0; 1683 } 1684 } 1685 1686 // The condition block is the implicit successor for the loop body as well as 1687 // any code above the loop. 1688 Succ = EntryConditionBlock; 1689 1690 // See if this is a known constant. 1691 TryResult KnownVal(true); 1692 1693 if (F->getCond()) 1694 KnownVal = tryEvaluateBool(F->getCond()); 1695 1696 // Now create the loop body. 1697 { 1698 assert(F->getBody()); 1699 1700 // Save the current values for Block, Succ, and continue targets. 1701 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1702 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1703 1704 // Create a new block to contain the (bottom) of the loop body. 1705 Block = NULL; 1706 1707 // Loop body should end with destructor of Condition variable (if any). 1708 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1709 1710 if (Stmt *I = F->getInc()) { 1711 // Generate increment code in its own basic block. This is the target of 1712 // continue statements. 1713 Succ = addStmt(I); 1714 } else { 1715 // No increment code. Create a special, empty, block that is used as the 1716 // target block for "looping back" to the start of the loop. 1717 assert(Succ == EntryConditionBlock); 1718 Succ = Block ? Block : createBlock(); 1719 } 1720 1721 // Finish up the increment (or empty) block if it hasn't been already. 1722 if (Block) { 1723 assert(Block == Succ); 1724 if (badCFG) 1725 return 0; 1726 Block = 0; 1727 } 1728 1729 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1730 1731 // The starting block for the loop increment is the block that should 1732 // represent the 'loop target' for looping back to the start of the loop. 1733 ContinueJumpTarget.block->setLoopTarget(F); 1734 1735 // If body is not a compound statement create implicit scope 1736 // and add destructors. 1737 if (!isa<CompoundStmt>(F->getBody())) 1738 addLocalScopeAndDtors(F->getBody()); 1739 1740 // Now populate the body block, and in the process create new blocks as we 1741 // walk the body of the loop. 1742 CFGBlock *BodyBlock = addStmt(F->getBody()); 1743 1744 if (!BodyBlock) 1745 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1746 else if (badCFG) 1747 return 0; 1748 1749 // This new body block is a successor to our "exit" condition block. 1750 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1751 } 1752 1753 // Link up the condition block with the code that follows the loop. (the 1754 // false branch). 1755 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1756 1757 // If the loop contains initialization, create a new block for those 1758 // statements. This block can also contain statements that precede the loop. 1759 if (Stmt *I = F->getInit()) { 1760 Block = createBlock(); 1761 return addStmt(I); 1762 } 1763 1764 // There is no loop initialization. We are thus basically a while loop. 1765 // NULL out Block to force lazy block construction. 1766 Block = NULL; 1767 Succ = EntryConditionBlock; 1768 return EntryConditionBlock; 1769} 1770 1771CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1772 if (asc.alwaysAdd(*this, M)) { 1773 autoCreateBlock(); 1774 appendStmt(Block, M); 1775 } 1776 return Visit(M->getBase()); 1777} 1778 1779CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 1780 // Objective-C fast enumeration 'for' statements: 1781 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1782 // 1783 // for ( Type newVariable in collection_expression ) { statements } 1784 // 1785 // becomes: 1786 // 1787 // prologue: 1788 // 1. collection_expression 1789 // T. jump to loop_entry 1790 // loop_entry: 1791 // 1. side-effects of element expression 1792 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1793 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1794 // TB: 1795 // statements 1796 // T. jump to loop_entry 1797 // FB: 1798 // what comes after 1799 // 1800 // and 1801 // 1802 // Type existingItem; 1803 // for ( existingItem in expression ) { statements } 1804 // 1805 // becomes: 1806 // 1807 // the same with newVariable replaced with existingItem; the binding works 1808 // the same except that for one ObjCForCollectionStmt::getElement() returns 1809 // a DeclStmt and the other returns a DeclRefExpr. 1810 // 1811 1812 CFGBlock *LoopSuccessor = 0; 1813 1814 if (Block) { 1815 if (badCFG) 1816 return 0; 1817 LoopSuccessor = Block; 1818 Block = 0; 1819 } else 1820 LoopSuccessor = Succ; 1821 1822 // Build the condition blocks. 1823 CFGBlock *ExitConditionBlock = createBlock(false); 1824 1825 // Set the terminator for the "exit" condition block. 1826 ExitConditionBlock->setTerminator(S); 1827 1828 // The last statement in the block should be the ObjCForCollectionStmt, which 1829 // performs the actual binding to 'element' and determines if there are any 1830 // more items in the collection. 1831 appendStmt(ExitConditionBlock, S); 1832 Block = ExitConditionBlock; 1833 1834 // Walk the 'element' expression to see if there are any side-effects. We 1835 // generate new blocks as necessary. We DON'T add the statement by default to 1836 // the CFG unless it contains control-flow. 1837 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 1838 AddStmtChoice::NotAlwaysAdd); 1839 if (Block) { 1840 if (badCFG) 1841 return 0; 1842 Block = 0; 1843 } 1844 1845 // The condition block is the implicit successor for the loop body as well as 1846 // any code above the loop. 1847 Succ = EntryConditionBlock; 1848 1849 // Now create the true branch. 1850 { 1851 // Save the current values for Succ, continue and break targets. 1852 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1853 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1854 save_break(BreakJumpTarget); 1855 1856 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1857 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1858 1859 CFGBlock *BodyBlock = addStmt(S->getBody()); 1860 1861 if (!BodyBlock) 1862 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1863 else if (Block) { 1864 if (badCFG) 1865 return 0; 1866 } 1867 1868 // This new body block is a successor to our "exit" condition block. 1869 addSuccessor(ExitConditionBlock, BodyBlock); 1870 } 1871 1872 // Link up the condition block with the code that follows the loop. 1873 // (the false branch). 1874 addSuccessor(ExitConditionBlock, LoopSuccessor); 1875 1876 // Now create a prologue block to contain the collection expression. 1877 Block = createBlock(); 1878 return addStmt(S->getCollection()); 1879} 1880 1881CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 1882 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1883 1884 // Inline the body. 1885 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1886 1887 // The sync body starts its own basic block. This makes it a little easier 1888 // for diagnostic clients. 1889 if (SyncBlock) { 1890 if (badCFG) 1891 return 0; 1892 1893 Block = 0; 1894 Succ = SyncBlock; 1895 } 1896 1897 // Add the @synchronized to the CFG. 1898 autoCreateBlock(); 1899 appendStmt(Block, S); 1900 1901 // Inline the sync expression. 1902 return addStmt(S->getSynchExpr()); 1903} 1904 1905CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 1906 // FIXME 1907 return NYS(); 1908} 1909 1910CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 1911 CFGBlock *LoopSuccessor = NULL; 1912 1913 // Save local scope position because in case of condition variable ScopePos 1914 // won't be restored when traversing AST. 1915 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1916 1917 // Create local scope for possible condition variable. 1918 // Store scope position for continue statement. 1919 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1920 if (VarDecl *VD = W->getConditionVariable()) { 1921 addLocalScopeForVarDecl(VD); 1922 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1923 } 1924 1925 // "while" is a control-flow statement. Thus we stop processing the current 1926 // block. 1927 if (Block) { 1928 if (badCFG) 1929 return 0; 1930 LoopSuccessor = Block; 1931 Block = 0; 1932 } else 1933 LoopSuccessor = Succ; 1934 1935 // Because of short-circuit evaluation, the condition of the loop can span 1936 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1937 // evaluate the condition. 1938 CFGBlock *ExitConditionBlock = createBlock(false); 1939 CFGBlock *EntryConditionBlock = ExitConditionBlock; 1940 1941 // Set the terminator for the "exit" condition block. 1942 ExitConditionBlock->setTerminator(W); 1943 1944 // Now add the actual condition to the condition block. Because the condition 1945 // itself may contain control-flow, new blocks may be created. Thus we update 1946 // "Succ" after adding the condition. 1947 if (Stmt *C = W->getCond()) { 1948 Block = ExitConditionBlock; 1949 EntryConditionBlock = addStmt(C); 1950 // The condition might finish the current 'Block'. 1951 Block = EntryConditionBlock; 1952 1953 // If this block contains a condition variable, add both the condition 1954 // variable and initializer to the CFG. 1955 if (VarDecl *VD = W->getConditionVariable()) { 1956 if (Expr *Init = VD->getInit()) { 1957 autoCreateBlock(); 1958 appendStmt(Block, W->getConditionVariableDeclStmt()); 1959 EntryConditionBlock = addStmt(Init); 1960 assert(Block == EntryConditionBlock); 1961 } 1962 } 1963 1964 if (Block) { 1965 if (badCFG) 1966 return 0; 1967 } 1968 } 1969 1970 // The condition block is the implicit successor for the loop body as well as 1971 // any code above the loop. 1972 Succ = EntryConditionBlock; 1973 1974 // See if this is a known constant. 1975 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1976 1977 // Process the loop body. 1978 { 1979 assert(W->getBody()); 1980 1981 // Save the current values for Block, Succ, and continue and break targets 1982 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1983 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1984 save_break(BreakJumpTarget); 1985 1986 // Create an empty block to represent the transition block for looping back 1987 // to the head of the loop. 1988 Block = 0; 1989 assert(Succ == EntryConditionBlock); 1990 Succ = createBlock(); 1991 Succ->setLoopTarget(W); 1992 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1993 1994 // All breaks should go to the code following the loop. 1995 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1996 1997 // NULL out Block to force lazy instantiation of blocks for the body. 1998 Block = NULL; 1999 2000 // Loop body should end with destructor of Condition variable (if any). 2001 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2002 2003 // If body is not a compound statement create implicit scope 2004 // and add destructors. 2005 if (!isa<CompoundStmt>(W->getBody())) 2006 addLocalScopeAndDtors(W->getBody()); 2007 2008 // Create the body. The returned block is the entry to the loop body. 2009 CFGBlock *BodyBlock = addStmt(W->getBody()); 2010 2011 if (!BodyBlock) 2012 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2013 else if (Block) { 2014 if (badCFG) 2015 return 0; 2016 } 2017 2018 // Add the loop body entry as a successor to the condition. 2019 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2020 } 2021 2022 // Link up the condition block with the code that follows the loop. (the 2023 // false branch). 2024 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2025 2026 // There can be no more statements in the condition block since we loop back 2027 // to this block. NULL out Block to force lazy creation of another block. 2028 Block = NULL; 2029 2030 // Return the condition block, which is the dominating block for the loop. 2031 Succ = EntryConditionBlock; 2032 return EntryConditionBlock; 2033} 2034 2035 2036CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2037 // FIXME: For now we pretend that @catch and the code it contains does not 2038 // exit. 2039 return Block; 2040} 2041 2042CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2043 // FIXME: This isn't complete. We basically treat @throw like a return 2044 // statement. 2045 2046 // If we were in the middle of a block we stop processing that block. 2047 if (badCFG) 2048 return 0; 2049 2050 // Create the new block. 2051 Block = createBlock(false); 2052 2053 // The Exit block is the only successor. 2054 addSuccessor(Block, &cfg->getExit()); 2055 2056 // Add the statement to the block. This may create new blocks if S contains 2057 // control-flow (short-circuit operations). 2058 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2059} 2060 2061CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2062 // If we were in the middle of a block we stop processing that block. 2063 if (badCFG) 2064 return 0; 2065 2066 // Create the new block. 2067 Block = createBlock(false); 2068 2069 if (TryTerminatedBlock) 2070 // The current try statement is the only successor. 2071 addSuccessor(Block, TryTerminatedBlock); 2072 else 2073 // otherwise the Exit block is the only successor. 2074 addSuccessor(Block, &cfg->getExit()); 2075 2076 // Add the statement to the block. This may create new blocks if S contains 2077 // control-flow (short-circuit operations). 2078 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2079} 2080 2081CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2082 CFGBlock *LoopSuccessor = NULL; 2083 2084 // "do...while" is a control-flow statement. Thus we stop processing the 2085 // current block. 2086 if (Block) { 2087 if (badCFG) 2088 return 0; 2089 LoopSuccessor = Block; 2090 } else 2091 LoopSuccessor = Succ; 2092 2093 // Because of short-circuit evaluation, the condition of the loop can span 2094 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2095 // evaluate the condition. 2096 CFGBlock *ExitConditionBlock = createBlock(false); 2097 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2098 2099 // Set the terminator for the "exit" condition block. 2100 ExitConditionBlock->setTerminator(D); 2101 2102 // Now add the actual condition to the condition block. Because the condition 2103 // itself may contain control-flow, new blocks may be created. 2104 if (Stmt *C = D->getCond()) { 2105 Block = ExitConditionBlock; 2106 EntryConditionBlock = addStmt(C); 2107 if (Block) { 2108 if (badCFG) 2109 return 0; 2110 } 2111 } 2112 2113 // The condition block is the implicit successor for the loop body. 2114 Succ = EntryConditionBlock; 2115 2116 // See if this is a known constant. 2117 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2118 2119 // Process the loop body. 2120 CFGBlock *BodyBlock = NULL; 2121 { 2122 assert(D->getBody()); 2123 2124 // Save the current values for Block, Succ, and continue and break targets 2125 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2126 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2127 save_break(BreakJumpTarget); 2128 2129 // All continues within this loop should go to the condition block 2130 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2131 2132 // All breaks should go to the code following the loop. 2133 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2134 2135 // NULL out Block to force lazy instantiation of blocks for the body. 2136 Block = NULL; 2137 2138 // If body is not a compound statement create implicit scope 2139 // and add destructors. 2140 if (!isa<CompoundStmt>(D->getBody())) 2141 addLocalScopeAndDtors(D->getBody()); 2142 2143 // Create the body. The returned block is the entry to the loop body. 2144 BodyBlock = addStmt(D->getBody()); 2145 2146 if (!BodyBlock) 2147 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2148 else if (Block) { 2149 if (badCFG) 2150 return 0; 2151 } 2152 2153 if (!KnownVal.isFalse()) { 2154 // Add an intermediate block between the BodyBlock and the 2155 // ExitConditionBlock to represent the "loop back" transition. Create an 2156 // empty block to represent the transition block for looping back to the 2157 // head of the loop. 2158 // FIXME: Can we do this more efficiently without adding another block? 2159 Block = NULL; 2160 Succ = BodyBlock; 2161 CFGBlock *LoopBackBlock = createBlock(); 2162 LoopBackBlock->setLoopTarget(D); 2163 2164 // Add the loop body entry as a successor to the condition. 2165 addSuccessor(ExitConditionBlock, LoopBackBlock); 2166 } 2167 else 2168 addSuccessor(ExitConditionBlock, NULL); 2169 } 2170 2171 // Link up the condition block with the code that follows the loop. 2172 // (the false branch). 2173 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2174 2175 // There can be no more statements in the body block(s) since we loop back to 2176 // the body. NULL out Block to force lazy creation of another block. 2177 Block = NULL; 2178 2179 // Return the loop body, which is the dominating block for the loop. 2180 Succ = BodyBlock; 2181 return BodyBlock; 2182} 2183 2184CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2185 // "continue" is a control-flow statement. Thus we stop processing the 2186 // current block. 2187 if (badCFG) 2188 return 0; 2189 2190 // Now create a new block that ends with the continue statement. 2191 Block = createBlock(false); 2192 Block->setTerminator(C); 2193 2194 // If there is no target for the continue, then we are looking at an 2195 // incomplete AST. This means the CFG cannot be constructed. 2196 if (ContinueJumpTarget.block) { 2197 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2198 addSuccessor(Block, ContinueJumpTarget.block); 2199 } else 2200 badCFG = true; 2201 2202 return Block; 2203} 2204 2205CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2206 AddStmtChoice asc) { 2207 2208 if (asc.alwaysAdd(*this, E)) { 2209 autoCreateBlock(); 2210 appendStmt(Block, E); 2211 } 2212 2213 // VLA types have expressions that must be evaluated. 2214 CFGBlock *lastBlock = Block; 2215 2216 if (E->isArgumentType()) { 2217 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2218 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2219 lastBlock = addStmt(VA->getSizeExpr()); 2220 } 2221 return lastBlock; 2222} 2223 2224/// VisitStmtExpr - Utility method to handle (nested) statement 2225/// expressions (a GCC extension). 2226CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2227 if (asc.alwaysAdd(*this, SE)) { 2228 autoCreateBlock(); 2229 appendStmt(Block, SE); 2230 } 2231 return VisitCompoundStmt(SE->getSubStmt()); 2232} 2233 2234CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2235 // "switch" is a control-flow statement. Thus we stop processing the current 2236 // block. 2237 CFGBlock *SwitchSuccessor = NULL; 2238 2239 // Save local scope position because in case of condition variable ScopePos 2240 // won't be restored when traversing AST. 2241 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2242 2243 // Create local scope for possible condition variable. 2244 // Store scope position. Add implicit destructor. 2245 if (VarDecl *VD = Terminator->getConditionVariable()) { 2246 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2247 addLocalScopeForVarDecl(VD); 2248 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2249 } 2250 2251 if (Block) { 2252 if (badCFG) 2253 return 0; 2254 SwitchSuccessor = Block; 2255 } else SwitchSuccessor = Succ; 2256 2257 // Save the current "switch" context. 2258 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2259 save_default(DefaultCaseBlock); 2260 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2261 2262 // Set the "default" case to be the block after the switch statement. If the 2263 // switch statement contains a "default:", this value will be overwritten with 2264 // the block for that code. 2265 DefaultCaseBlock = SwitchSuccessor; 2266 2267 // Create a new block that will contain the switch statement. 2268 SwitchTerminatedBlock = createBlock(false); 2269 2270 // Now process the switch body. The code after the switch is the implicit 2271 // successor. 2272 Succ = SwitchSuccessor; 2273 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2274 2275 // When visiting the body, the case statements should automatically get linked 2276 // up to the switch. We also don't keep a pointer to the body, since all 2277 // control-flow from the switch goes to case/default statements. 2278 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2279 Block = NULL; 2280 2281 // For pruning unreachable case statements, save the current state 2282 // for tracking the condition value. 2283 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2284 false); 2285 2286 // Determine if the switch condition can be explicitly evaluated. 2287 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2288 Expr::EvalResult result; 2289 bool b = tryEvaluate(Terminator->getCond(), result); 2290 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2291 b ? &result : 0); 2292 2293 // If body is not a compound statement create implicit scope 2294 // and add destructors. 2295 if (!isa<CompoundStmt>(Terminator->getBody())) 2296 addLocalScopeAndDtors(Terminator->getBody()); 2297 2298 addStmt(Terminator->getBody()); 2299 if (Block) { 2300 if (badCFG) 2301 return 0; 2302 } 2303 2304 // If we have no "default:" case, the default transition is to the code 2305 // following the switch body. Moreover, take into account if all the 2306 // cases of a switch are covered (e.g., switching on an enum value). 2307 addSuccessor(SwitchTerminatedBlock, 2308 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2309 ? 0 : DefaultCaseBlock); 2310 2311 // Add the terminator and condition in the switch block. 2312 SwitchTerminatedBlock->setTerminator(Terminator); 2313 Block = SwitchTerminatedBlock; 2314 Block = addStmt(Terminator->getCond()); 2315 2316 // Finally, if the SwitchStmt contains a condition variable, add both the 2317 // SwitchStmt and the condition variable initialization to the CFG. 2318 if (VarDecl *VD = Terminator->getConditionVariable()) { 2319 if (Expr *Init = VD->getInit()) { 2320 autoCreateBlock(); 2321 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2322 addStmt(Init); 2323 } 2324 } 2325 2326 return Block; 2327} 2328 2329static bool shouldAddCase(bool &switchExclusivelyCovered, 2330 const Expr::EvalResult *switchCond, 2331 const CaseStmt *CS, 2332 ASTContext &Ctx) { 2333 if (!switchCond) 2334 return true; 2335 2336 bool addCase = false; 2337 2338 if (!switchExclusivelyCovered) { 2339 if (switchCond->Val.isInt()) { 2340 // Evaluate the LHS of the case value. 2341 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2342 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2343 2344 if (condInt == lhsInt) { 2345 addCase = true; 2346 switchExclusivelyCovered = true; 2347 } 2348 else if (condInt < lhsInt) { 2349 if (const Expr *RHS = CS->getRHS()) { 2350 // Evaluate the RHS of the case value. 2351 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2352 if (V2 <= condInt) { 2353 addCase = true; 2354 switchExclusivelyCovered = true; 2355 } 2356 } 2357 } 2358 } 2359 else 2360 addCase = true; 2361 } 2362 return addCase; 2363} 2364 2365CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2366 // CaseStmts are essentially labels, so they are the first statement in a 2367 // block. 2368 CFGBlock *TopBlock = 0, *LastBlock = 0; 2369 2370 if (Stmt *Sub = CS->getSubStmt()) { 2371 // For deeply nested chains of CaseStmts, instead of doing a recursion 2372 // (which can blow out the stack), manually unroll and create blocks 2373 // along the way. 2374 while (isa<CaseStmt>(Sub)) { 2375 CFGBlock *currentBlock = createBlock(false); 2376 currentBlock->setLabel(CS); 2377 2378 if (TopBlock) 2379 addSuccessor(LastBlock, currentBlock); 2380 else 2381 TopBlock = currentBlock; 2382 2383 addSuccessor(SwitchTerminatedBlock, 2384 shouldAddCase(switchExclusivelyCovered, switchCond, 2385 CS, *Context) 2386 ? currentBlock : 0); 2387 2388 LastBlock = currentBlock; 2389 CS = cast<CaseStmt>(Sub); 2390 Sub = CS->getSubStmt(); 2391 } 2392 2393 addStmt(Sub); 2394 } 2395 2396 CFGBlock *CaseBlock = Block; 2397 if (!CaseBlock) 2398 CaseBlock = createBlock(); 2399 2400 // Cases statements partition blocks, so this is the top of the basic block we 2401 // were processing (the "case XXX:" is the label). 2402 CaseBlock->setLabel(CS); 2403 2404 if (badCFG) 2405 return 0; 2406 2407 // Add this block to the list of successors for the block with the switch 2408 // statement. 2409 assert(SwitchTerminatedBlock); 2410 addSuccessor(SwitchTerminatedBlock, 2411 shouldAddCase(switchExclusivelyCovered, switchCond, 2412 CS, *Context) 2413 ? CaseBlock : 0); 2414 2415 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2416 Block = NULL; 2417 2418 if (TopBlock) { 2419 addSuccessor(LastBlock, CaseBlock); 2420 Succ = TopBlock; 2421 } else { 2422 // This block is now the implicit successor of other blocks. 2423 Succ = CaseBlock; 2424 } 2425 2426 return Succ; 2427} 2428 2429CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2430 if (Terminator->getSubStmt()) 2431 addStmt(Terminator->getSubStmt()); 2432 2433 DefaultCaseBlock = Block; 2434 2435 if (!DefaultCaseBlock) 2436 DefaultCaseBlock = createBlock(); 2437 2438 // Default statements partition blocks, so this is the top of the basic block 2439 // we were processing (the "default:" is the label). 2440 DefaultCaseBlock->setLabel(Terminator); 2441 2442 if (badCFG) 2443 return 0; 2444 2445 // Unlike case statements, we don't add the default block to the successors 2446 // for the switch statement immediately. This is done when we finish 2447 // processing the switch statement. This allows for the default case 2448 // (including a fall-through to the code after the switch statement) to always 2449 // be the last successor of a switch-terminated block. 2450 2451 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2452 Block = NULL; 2453 2454 // This block is now the implicit successor of other blocks. 2455 Succ = DefaultCaseBlock; 2456 2457 return DefaultCaseBlock; 2458} 2459 2460CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2461 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2462 // current block. 2463 CFGBlock *TrySuccessor = NULL; 2464 2465 if (Block) { 2466 if (badCFG) 2467 return 0; 2468 TrySuccessor = Block; 2469 } else TrySuccessor = Succ; 2470 2471 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2472 2473 // Create a new block that will contain the try statement. 2474 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2475 // Add the terminator in the try block. 2476 NewTryTerminatedBlock->setTerminator(Terminator); 2477 2478 bool HasCatchAll = false; 2479 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2480 // The code after the try is the implicit successor. 2481 Succ = TrySuccessor; 2482 CXXCatchStmt *CS = Terminator->getHandler(h); 2483 if (CS->getExceptionDecl() == 0) { 2484 HasCatchAll = true; 2485 } 2486 Block = NULL; 2487 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2488 if (CatchBlock == 0) 2489 return 0; 2490 // Add this block to the list of successors for the block with the try 2491 // statement. 2492 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2493 } 2494 if (!HasCatchAll) { 2495 if (PrevTryTerminatedBlock) 2496 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2497 else 2498 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2499 } 2500 2501 // The code after the try is the implicit successor. 2502 Succ = TrySuccessor; 2503 2504 // Save the current "try" context. 2505 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2506 cfg->addTryDispatchBlock(TryTerminatedBlock); 2507 2508 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2509 Block = NULL; 2510 Block = addStmt(Terminator->getTryBlock()); 2511 return Block; 2512} 2513 2514CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2515 // CXXCatchStmt are treated like labels, so they are the first statement in a 2516 // block. 2517 2518 // Save local scope position because in case of exception variable ScopePos 2519 // won't be restored when traversing AST. 2520 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2521 2522 // Create local scope for possible exception variable. 2523 // Store scope position. Add implicit destructor. 2524 if (VarDecl *VD = CS->getExceptionDecl()) { 2525 LocalScope::const_iterator BeginScopePos = ScopePos; 2526 addLocalScopeForVarDecl(VD); 2527 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2528 } 2529 2530 if (CS->getHandlerBlock()) 2531 addStmt(CS->getHandlerBlock()); 2532 2533 CFGBlock *CatchBlock = Block; 2534 if (!CatchBlock) 2535 CatchBlock = createBlock(); 2536 2537 CatchBlock->setLabel(CS); 2538 2539 if (badCFG) 2540 return 0; 2541 2542 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2543 Block = NULL; 2544 2545 return CatchBlock; 2546} 2547 2548CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2549 // C++0x for-range statements are specified as [stmt.ranged]: 2550 // 2551 // { 2552 // auto && __range = range-init; 2553 // for ( auto __begin = begin-expr, 2554 // __end = end-expr; 2555 // __begin != __end; 2556 // ++__begin ) { 2557 // for-range-declaration = *__begin; 2558 // statement 2559 // } 2560 // } 2561 2562 // Save local scope position before the addition of the implicit variables. 2563 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2564 2565 // Create local scopes and destructors for range, begin and end variables. 2566 if (Stmt *Range = S->getRangeStmt()) 2567 addLocalScopeForStmt(Range); 2568 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2569 addLocalScopeForStmt(BeginEnd); 2570 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2571 2572 LocalScope::const_iterator ContinueScopePos = ScopePos; 2573 2574 // "for" is a control-flow statement. Thus we stop processing the current 2575 // block. 2576 CFGBlock *LoopSuccessor = NULL; 2577 if (Block) { 2578 if (badCFG) 2579 return 0; 2580 LoopSuccessor = Block; 2581 } else 2582 LoopSuccessor = Succ; 2583 2584 // Save the current value for the break targets. 2585 // All breaks should go to the code following the loop. 2586 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2587 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2588 2589 // The block for the __begin != __end expression. 2590 CFGBlock *ConditionBlock = createBlock(false); 2591 ConditionBlock->setTerminator(S); 2592 2593 // Now add the actual condition to the condition block. 2594 if (Expr *C = S->getCond()) { 2595 Block = ConditionBlock; 2596 CFGBlock *BeginConditionBlock = addStmt(C); 2597 if (badCFG) 2598 return 0; 2599 assert(BeginConditionBlock == ConditionBlock && 2600 "condition block in for-range was unexpectedly complex"); 2601 (void)BeginConditionBlock; 2602 } 2603 2604 // The condition block is the implicit successor for the loop body as well as 2605 // any code above the loop. 2606 Succ = ConditionBlock; 2607 2608 // See if this is a known constant. 2609 TryResult KnownVal(true); 2610 2611 if (S->getCond()) 2612 KnownVal = tryEvaluateBool(S->getCond()); 2613 2614 // Now create the loop body. 2615 { 2616 assert(S->getBody()); 2617 2618 // Save the current values for Block, Succ, and continue targets. 2619 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2620 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2621 2622 // Generate increment code in its own basic block. This is the target of 2623 // continue statements. 2624 Block = 0; 2625 Succ = addStmt(S->getInc()); 2626 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2627 2628 // The starting block for the loop increment is the block that should 2629 // represent the 'loop target' for looping back to the start of the loop. 2630 ContinueJumpTarget.block->setLoopTarget(S); 2631 2632 // Finish up the increment block and prepare to start the loop body. 2633 assert(Block); 2634 if (badCFG) 2635 return 0; 2636 Block = 0; 2637 2638 2639 // Add implicit scope and dtors for loop variable. 2640 addLocalScopeAndDtors(S->getLoopVarStmt()); 2641 2642 // Populate a new block to contain the loop body and loop variable. 2643 Block = addStmt(S->getBody()); 2644 if (badCFG) 2645 return 0; 2646 Block = addStmt(S->getLoopVarStmt()); 2647 if (badCFG) 2648 return 0; 2649 2650 // This new body block is a successor to our condition block. 2651 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2652 } 2653 2654 // Link up the condition block with the code that follows the loop (the 2655 // false branch). 2656 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2657 2658 // Add the initialization statements. 2659 Block = createBlock(); 2660 addStmt(S->getBeginEndStmt()); 2661 return addStmt(S->getRangeStmt()); 2662} 2663 2664CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2665 AddStmtChoice asc) { 2666 if (BuildOpts.AddImplicitDtors) { 2667 // If adding implicit destructors visit the full expression for adding 2668 // destructors of temporaries. 2669 VisitForTemporaryDtors(E->getSubExpr()); 2670 2671 // Full expression has to be added as CFGStmt so it will be sequenced 2672 // before destructors of it's temporaries. 2673 asc = asc.withAlwaysAdd(true); 2674 } 2675 return Visit(E->getSubExpr(), asc); 2676} 2677 2678CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2679 AddStmtChoice asc) { 2680 if (asc.alwaysAdd(*this, E)) { 2681 autoCreateBlock(); 2682 appendStmt(Block, E); 2683 2684 // We do not want to propagate the AlwaysAdd property. 2685 asc = asc.withAlwaysAdd(false); 2686 } 2687 return Visit(E->getSubExpr(), asc); 2688} 2689 2690CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2691 AddStmtChoice asc) { 2692 autoCreateBlock(); 2693 if (!C->isElidable()) 2694 appendStmt(Block, C); 2695 2696 return VisitChildren(C); 2697} 2698 2699CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2700 AddStmtChoice asc) { 2701 if (asc.alwaysAdd(*this, E)) { 2702 autoCreateBlock(); 2703 appendStmt(Block, E); 2704 // We do not want to propagate the AlwaysAdd property. 2705 asc = asc.withAlwaysAdd(false); 2706 } 2707 return Visit(E->getSubExpr(), asc); 2708} 2709 2710CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2711 AddStmtChoice asc) { 2712 autoCreateBlock(); 2713 appendStmt(Block, C); 2714 return VisitChildren(C); 2715} 2716 2717CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2718 AddStmtChoice asc) { 2719 if (asc.alwaysAdd(*this, E)) { 2720 autoCreateBlock(); 2721 appendStmt(Block, E); 2722 } 2723 return Visit(E->getSubExpr(), AddStmtChoice()); 2724} 2725 2726CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 2727 // Lazily create the indirect-goto dispatch block if there isn't one already. 2728 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 2729 2730 if (!IBlock) { 2731 IBlock = createBlock(false); 2732 cfg->setIndirectGotoBlock(IBlock); 2733 } 2734 2735 // IndirectGoto is a control-flow statement. Thus we stop processing the 2736 // current block and create a new one. 2737 if (badCFG) 2738 return 0; 2739 2740 Block = createBlock(false); 2741 Block->setTerminator(I); 2742 addSuccessor(Block, IBlock); 2743 return addStmt(I->getTarget()); 2744} 2745 2746CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2747tryAgain: 2748 if (!E) { 2749 badCFG = true; 2750 return NULL; 2751 } 2752 switch (E->getStmtClass()) { 2753 default: 2754 return VisitChildrenForTemporaryDtors(E); 2755 2756 case Stmt::BinaryOperatorClass: 2757 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2758 2759 case Stmt::CXXBindTemporaryExprClass: 2760 return VisitCXXBindTemporaryExprForTemporaryDtors( 2761 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2762 2763 case Stmt::BinaryConditionalOperatorClass: 2764 case Stmt::ConditionalOperatorClass: 2765 return VisitConditionalOperatorForTemporaryDtors( 2766 cast<AbstractConditionalOperator>(E), BindToTemporary); 2767 2768 case Stmt::ImplicitCastExprClass: 2769 // For implicit cast we want BindToTemporary to be passed further. 2770 E = cast<CastExpr>(E)->getSubExpr(); 2771 goto tryAgain; 2772 2773 case Stmt::ParenExprClass: 2774 E = cast<ParenExpr>(E)->getSubExpr(); 2775 goto tryAgain; 2776 2777 case Stmt::MaterializeTemporaryExprClass: 2778 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 2779 goto tryAgain; 2780 } 2781} 2782 2783CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2784 // When visiting children for destructors we want to visit them in reverse 2785 // order. Because there's no reverse iterator for children must to reverse 2786 // them in helper vector. 2787 typedef SmallVector<Stmt *, 4> ChildrenVect; 2788 ChildrenVect ChildrenRev; 2789 for (Stmt::child_range I = E->children(); I; ++I) { 2790 if (*I) ChildrenRev.push_back(*I); 2791 } 2792 2793 CFGBlock *B = Block; 2794 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2795 L = ChildrenRev.rend(); I != L; ++I) { 2796 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2797 B = R; 2798 } 2799 return B; 2800} 2801 2802CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2803 if (E->isLogicalOp()) { 2804 // Destructors for temporaries in LHS expression should be called after 2805 // those for RHS expression. Even if this will unnecessarily create a block, 2806 // this block will be used at least by the full expression. 2807 autoCreateBlock(); 2808 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2809 if (badCFG) 2810 return NULL; 2811 2812 Succ = ConfluenceBlock; 2813 Block = NULL; 2814 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2815 2816 if (RHSBlock) { 2817 if (badCFG) 2818 return NULL; 2819 2820 // If RHS expression did produce destructors we need to connect created 2821 // blocks to CFG in same manner as for binary operator itself. 2822 CFGBlock *LHSBlock = createBlock(false); 2823 LHSBlock->setTerminator(CFGTerminator(E, true)); 2824 2825 // For binary operator LHS block is before RHS in list of predecessors 2826 // of ConfluenceBlock. 2827 std::reverse(ConfluenceBlock->pred_begin(), 2828 ConfluenceBlock->pred_end()); 2829 2830 // See if this is a known constant. 2831 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2832 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2833 KnownVal.negate(); 2834 2835 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2836 // itself. 2837 if (E->getOpcode() == BO_LOr) { 2838 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2839 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2840 } else { 2841 assert (E->getOpcode() == BO_LAnd); 2842 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2843 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2844 } 2845 2846 Block = LHSBlock; 2847 return LHSBlock; 2848 } 2849 2850 Block = ConfluenceBlock; 2851 return ConfluenceBlock; 2852 } 2853 2854 if (E->isAssignmentOp()) { 2855 // For assignment operator (=) LHS expression is visited 2856 // before RHS expression. For destructors visit them in reverse order. 2857 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2858 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2859 return LHSBlock ? LHSBlock : RHSBlock; 2860 } 2861 2862 // For any other binary operator RHS expression is visited before 2863 // LHS expression (order of children). For destructors visit them in reverse 2864 // order. 2865 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2866 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2867 return RHSBlock ? RHSBlock : LHSBlock; 2868} 2869 2870CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2871 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2872 // First add destructors for temporaries in subexpression. 2873 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2874 if (!BindToTemporary) { 2875 // If lifetime of temporary is not prolonged (by assigning to constant 2876 // reference) add destructor for it. 2877 2878 // If the destructor is marked as a no-return destructor, we need to create 2879 // a new block for the destructor which does not have as a successor 2880 // anything built thus far. Control won't flow out of this block. 2881 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 2882 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) 2883 Block = createNoReturnBlock(); 2884 else 2885 autoCreateBlock(); 2886 2887 appendTemporaryDtor(Block, E); 2888 B = Block; 2889 } 2890 return B; 2891} 2892 2893CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2894 AbstractConditionalOperator *E, bool BindToTemporary) { 2895 // First add destructors for condition expression. Even if this will 2896 // unnecessarily create a block, this block will be used at least by the full 2897 // expression. 2898 autoCreateBlock(); 2899 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2900 if (badCFG) 2901 return NULL; 2902 if (BinaryConditionalOperator *BCO 2903 = dyn_cast<BinaryConditionalOperator>(E)) { 2904 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2905 if (badCFG) 2906 return NULL; 2907 } 2908 2909 // Try to add block with destructors for LHS expression. 2910 CFGBlock *LHSBlock = NULL; 2911 Succ = ConfluenceBlock; 2912 Block = NULL; 2913 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2914 if (badCFG) 2915 return NULL; 2916 2917 // Try to add block with destructors for RHS expression; 2918 Succ = ConfluenceBlock; 2919 Block = NULL; 2920 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2921 BindToTemporary); 2922 if (badCFG) 2923 return NULL; 2924 2925 if (!RHSBlock && !LHSBlock) { 2926 // If neither LHS nor RHS expression had temporaries to destroy don't create 2927 // more blocks. 2928 Block = ConfluenceBlock; 2929 return Block; 2930 } 2931 2932 Block = createBlock(false); 2933 Block->setTerminator(CFGTerminator(E, true)); 2934 2935 // See if this is a known constant. 2936 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2937 2938 if (LHSBlock) { 2939 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2940 } else if (KnownVal.isFalse()) { 2941 addSuccessor(Block, NULL); 2942 } else { 2943 addSuccessor(Block, ConfluenceBlock); 2944 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2945 } 2946 2947 if (!RHSBlock) 2948 RHSBlock = ConfluenceBlock; 2949 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2950 2951 return Block; 2952} 2953 2954} // end anonymous namespace 2955 2956/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2957/// no successors or predecessors. If this is the first block created in the 2958/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2959CFGBlock *CFG::createBlock() { 2960 bool first_block = begin() == end(); 2961 2962 // Create the block. 2963 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2964 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2965 Blocks.push_back(Mem, BlkBVC); 2966 2967 // If this is the first block, set it as the Entry and Exit. 2968 if (first_block) 2969 Entry = Exit = &back(); 2970 2971 // Return the block. 2972 return &back(); 2973} 2974 2975/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2976/// CFG is returned to the caller. 2977CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 2978 const BuildOptions &BO) { 2979 CFGBuilder Builder(C, BO); 2980 return Builder.buildCFG(D, Statement); 2981} 2982 2983const CXXDestructorDecl * 2984CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 2985 switch (getKind()) { 2986 case CFGElement::Invalid: 2987 case CFGElement::Statement: 2988 case CFGElement::Initializer: 2989 llvm_unreachable("getDestructorDecl should only be used with " 2990 "ImplicitDtors"); 2991 case CFGElement::AutomaticObjectDtor: { 2992 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 2993 QualType ty = var->getType(); 2994 ty = ty.getNonReferenceType(); 2995 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 2996 ty = arrayType->getElementType(); 2997 } 2998 const RecordType *recordType = ty->getAs<RecordType>(); 2999 const CXXRecordDecl *classDecl = 3000 cast<CXXRecordDecl>(recordType->getDecl()); 3001 return classDecl->getDestructor(); 3002 } 3003 case CFGElement::TemporaryDtor: { 3004 const CXXBindTemporaryExpr *bindExpr = 3005 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 3006 const CXXTemporary *temp = bindExpr->getTemporary(); 3007 return temp->getDestructor(); 3008 } 3009 case CFGElement::BaseDtor: 3010 case CFGElement::MemberDtor: 3011 3012 // Not yet supported. 3013 return 0; 3014 } 3015 llvm_unreachable("getKind() returned bogus value"); 3016 return 0; 3017} 3018 3019bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3020 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 3021 QualType ty = cdecl->getType(); 3022 return cast<FunctionType>(ty)->getNoReturnAttr(); 3023 } 3024 return false; 3025} 3026 3027//===----------------------------------------------------------------------===// 3028// CFG: Queries for BlkExprs. 3029//===----------------------------------------------------------------------===// 3030 3031namespace { 3032 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3033} 3034 3035static void FindSubExprAssignments(const Stmt *S, 3036 llvm::SmallPtrSet<const Expr*,50>& Set) { 3037 if (!S) 3038 return; 3039 3040 for (Stmt::const_child_range I = S->children(); I; ++I) { 3041 const Stmt *child = *I; 3042 if (!child) 3043 continue; 3044 3045 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3046 if (B->isAssignmentOp()) Set.insert(B); 3047 3048 FindSubExprAssignments(child, Set); 3049 } 3050} 3051 3052static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3053 BlkExprMapTy* M = new BlkExprMapTy(); 3054 3055 // Look for assignments that are used as subexpressions. These are the only 3056 // assignments that we want to *possibly* register as a block-level 3057 // expression. Basically, if an assignment occurs both in a subexpression and 3058 // at the block-level, it is a block-level expression. 3059 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3060 3061 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3062 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3063 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3064 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3065 3066 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3067 3068 // Iterate over the statements again on identify the Expr* and Stmt* at the 3069 // block-level that are block-level expressions. 3070 3071 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3072 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3073 if (!CS) 3074 continue; 3075 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3076 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3077 3078 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3079 // Assignment expressions that are not nested within another 3080 // expression are really "statements" whose value is never used by 3081 // another expression. 3082 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3083 continue; 3084 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3085 // Special handling for statement expressions. The last statement in 3086 // the statement expression is also a block-level expr. 3087 const CompoundStmt *C = SE->getSubStmt(); 3088 if (!C->body_empty()) { 3089 const Stmt *Last = C->body_back(); 3090 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3091 Last = LastEx->IgnoreParens(); 3092 unsigned x = M->size(); 3093 (*M)[Last] = x; 3094 } 3095 } 3096 3097 unsigned x = M->size(); 3098 (*M)[Exp] = x; 3099 } 3100 } 3101 3102 // Look at terminators. The condition is a block-level expression. 3103 3104 Stmt *S = (*I)->getTerminatorCondition(); 3105 3106 if (S && M->find(S) == M->end()) { 3107 unsigned x = M->size(); 3108 (*M)[S] = x; 3109 } 3110 } 3111 3112 return M; 3113} 3114 3115CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3116 assert(S != NULL); 3117 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3118 3119 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3120 BlkExprMapTy::iterator I = M->find(S); 3121 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3122} 3123 3124unsigned CFG::getNumBlkExprs() { 3125 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3126 return M->size(); 3127 3128 // We assume callers interested in the number of BlkExprs will want 3129 // the map constructed if it doesn't already exist. 3130 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3131 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3132} 3133 3134//===----------------------------------------------------------------------===// 3135// Filtered walking of the CFG. 3136//===----------------------------------------------------------------------===// 3137 3138bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3139 const CFGBlock *From, const CFGBlock *To) { 3140 3141 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3142 // If the 'To' has no label or is labeled but the label isn't a 3143 // CaseStmt then filter this edge. 3144 if (const SwitchStmt *S = 3145 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3146 if (S->isAllEnumCasesCovered()) { 3147 const Stmt *L = To->getLabel(); 3148 if (!L || !isa<CaseStmt>(L)) 3149 return true; 3150 } 3151 } 3152 } 3153 3154 return false; 3155} 3156 3157//===----------------------------------------------------------------------===// 3158// Cleanup: CFG dstor. 3159//===----------------------------------------------------------------------===// 3160 3161CFG::~CFG() { 3162 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3163} 3164 3165//===----------------------------------------------------------------------===// 3166// CFG pretty printing 3167//===----------------------------------------------------------------------===// 3168 3169namespace { 3170 3171class StmtPrinterHelper : public PrinterHelper { 3172 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3173 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3174 StmtMapTy StmtMap; 3175 DeclMapTy DeclMap; 3176 signed currentBlock; 3177 unsigned currentStmt; 3178 const LangOptions &LangOpts; 3179public: 3180 3181 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3182 : currentBlock(0), currentStmt(0), LangOpts(LO) 3183 { 3184 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3185 unsigned j = 1; 3186 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3187 BI != BEnd; ++BI, ++j ) { 3188 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3189 const Stmt *stmt= SE->getStmt(); 3190 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3191 StmtMap[stmt] = P; 3192 3193 switch (stmt->getStmtClass()) { 3194 case Stmt::DeclStmtClass: 3195 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3196 break; 3197 case Stmt::IfStmtClass: { 3198 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3199 if (var) 3200 DeclMap[var] = P; 3201 break; 3202 } 3203 case Stmt::ForStmtClass: { 3204 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3205 if (var) 3206 DeclMap[var] = P; 3207 break; 3208 } 3209 case Stmt::WhileStmtClass: { 3210 const VarDecl *var = 3211 cast<WhileStmt>(stmt)->getConditionVariable(); 3212 if (var) 3213 DeclMap[var] = P; 3214 break; 3215 } 3216 case Stmt::SwitchStmtClass: { 3217 const VarDecl *var = 3218 cast<SwitchStmt>(stmt)->getConditionVariable(); 3219 if (var) 3220 DeclMap[var] = P; 3221 break; 3222 } 3223 case Stmt::CXXCatchStmtClass: { 3224 const VarDecl *var = 3225 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3226 if (var) 3227 DeclMap[var] = P; 3228 break; 3229 } 3230 default: 3231 break; 3232 } 3233 } 3234 } 3235 } 3236 } 3237 3238 3239 virtual ~StmtPrinterHelper() {} 3240 3241 const LangOptions &getLangOpts() const { return LangOpts; } 3242 void setBlockID(signed i) { currentBlock = i; } 3243 void setStmtID(unsigned i) { currentStmt = i; } 3244 3245 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3246 StmtMapTy::iterator I = StmtMap.find(S); 3247 3248 if (I == StmtMap.end()) 3249 return false; 3250 3251 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3252 && I->second.second == currentStmt) { 3253 return false; 3254 } 3255 3256 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3257 return true; 3258 } 3259 3260 bool handleDecl(const Decl *D, raw_ostream &OS) { 3261 DeclMapTy::iterator I = DeclMap.find(D); 3262 3263 if (I == DeclMap.end()) 3264 return false; 3265 3266 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3267 && I->second.second == currentStmt) { 3268 return false; 3269 } 3270 3271 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3272 return true; 3273 } 3274}; 3275} // end anonymous namespace 3276 3277 3278namespace { 3279class CFGBlockTerminatorPrint 3280 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3281 3282 raw_ostream &OS; 3283 StmtPrinterHelper* Helper; 3284 PrintingPolicy Policy; 3285public: 3286 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3287 const PrintingPolicy &Policy) 3288 : OS(os), Helper(helper), Policy(Policy) {} 3289 3290 void VisitIfStmt(IfStmt *I) { 3291 OS << "if "; 3292 I->getCond()->printPretty(OS,Helper,Policy); 3293 } 3294 3295 // Default case. 3296 void VisitStmt(Stmt *Terminator) { 3297 Terminator->printPretty(OS, Helper, Policy); 3298 } 3299 3300 void VisitForStmt(ForStmt *F) { 3301 OS << "for (" ; 3302 if (F->getInit()) 3303 OS << "..."; 3304 OS << "; "; 3305 if (Stmt *C = F->getCond()) 3306 C->printPretty(OS, Helper, Policy); 3307 OS << "; "; 3308 if (F->getInc()) 3309 OS << "..."; 3310 OS << ")"; 3311 } 3312 3313 void VisitWhileStmt(WhileStmt *W) { 3314 OS << "while " ; 3315 if (Stmt *C = W->getCond()) 3316 C->printPretty(OS, Helper, Policy); 3317 } 3318 3319 void VisitDoStmt(DoStmt *D) { 3320 OS << "do ... while "; 3321 if (Stmt *C = D->getCond()) 3322 C->printPretty(OS, Helper, Policy); 3323 } 3324 3325 void VisitSwitchStmt(SwitchStmt *Terminator) { 3326 OS << "switch "; 3327 Terminator->getCond()->printPretty(OS, Helper, Policy); 3328 } 3329 3330 void VisitCXXTryStmt(CXXTryStmt *CS) { 3331 OS << "try ..."; 3332 } 3333 3334 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3335 C->getCond()->printPretty(OS, Helper, Policy); 3336 OS << " ? ... : ..."; 3337 } 3338 3339 void VisitChooseExpr(ChooseExpr *C) { 3340 OS << "__builtin_choose_expr( "; 3341 C->getCond()->printPretty(OS, Helper, Policy); 3342 OS << " )"; 3343 } 3344 3345 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3346 OS << "goto *"; 3347 I->getTarget()->printPretty(OS, Helper, Policy); 3348 } 3349 3350 void VisitBinaryOperator(BinaryOperator* B) { 3351 if (!B->isLogicalOp()) { 3352 VisitExpr(B); 3353 return; 3354 } 3355 3356 B->getLHS()->printPretty(OS, Helper, Policy); 3357 3358 switch (B->getOpcode()) { 3359 case BO_LOr: 3360 OS << " || ..."; 3361 return; 3362 case BO_LAnd: 3363 OS << " && ..."; 3364 return; 3365 default: 3366 llvm_unreachable("Invalid logical operator."); 3367 } 3368 } 3369 3370 void VisitExpr(Expr *E) { 3371 E->printPretty(OS, Helper, Policy); 3372 } 3373}; 3374} // end anonymous namespace 3375 3376static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3377 const CFGElement &E) { 3378 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3379 const Stmt *S = CS->getStmt(); 3380 3381 if (Helper) { 3382 3383 // special printing for statement-expressions. 3384 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3385 const CompoundStmt *Sub = SE->getSubStmt(); 3386 3387 if (Sub->children()) { 3388 OS << "({ ... ; "; 3389 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3390 OS << " })\n"; 3391 return; 3392 } 3393 } 3394 // special printing for comma expressions. 3395 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3396 if (B->getOpcode() == BO_Comma) { 3397 OS << "... , "; 3398 Helper->handledStmt(B->getRHS(),OS); 3399 OS << '\n'; 3400 return; 3401 } 3402 } 3403 } 3404 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3405 3406 if (isa<CXXOperatorCallExpr>(S)) { 3407 OS << " (OperatorCall)"; 3408 } else if (isa<CXXBindTemporaryExpr>(S)) { 3409 OS << " (BindTemporary)"; 3410 } 3411 3412 // Expressions need a newline. 3413 if (isa<Expr>(S)) 3414 OS << '\n'; 3415 3416 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3417 const CXXCtorInitializer *I = IE->getInitializer(); 3418 if (I->isBaseInitializer()) 3419 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3420 else OS << I->getAnyMember()->getName(); 3421 3422 OS << "("; 3423 if (Expr *IE = I->getInit()) 3424 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3425 OS << ")"; 3426 3427 if (I->isBaseInitializer()) 3428 OS << " (Base initializer)\n"; 3429 else OS << " (Member initializer)\n"; 3430 3431 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3432 const VarDecl *VD = DE->getVarDecl(); 3433 Helper->handleDecl(VD, OS); 3434 3435 const Type* T = VD->getType().getTypePtr(); 3436 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3437 T = RT->getPointeeType().getTypePtr(); 3438 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3439 T = ET; 3440 3441 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3442 OS << " (Implicit destructor)\n"; 3443 3444 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3445 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3446 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3447 OS << " (Base object destructor)\n"; 3448 3449 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3450 const FieldDecl *FD = ME->getFieldDecl(); 3451 3452 const Type *T = FD->getType().getTypePtr(); 3453 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3454 T = ET; 3455 3456 OS << "this->" << FD->getName(); 3457 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3458 OS << " (Member object destructor)\n"; 3459 3460 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3461 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3462 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3463 OS << " (Temporary object destructor)\n"; 3464 } 3465} 3466 3467static void print_block(raw_ostream &OS, const CFG* cfg, 3468 const CFGBlock &B, 3469 StmtPrinterHelper* Helper, bool print_edges) { 3470 3471 if (Helper) Helper->setBlockID(B.getBlockID()); 3472 3473 // Print the header. 3474 OS << "\n [ B" << B.getBlockID(); 3475 3476 if (&B == &cfg->getEntry()) 3477 OS << " (ENTRY) ]\n"; 3478 else if (&B == &cfg->getExit()) 3479 OS << " (EXIT) ]\n"; 3480 else if (&B == cfg->getIndirectGotoBlock()) 3481 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3482 else 3483 OS << " ]\n"; 3484 3485 // Print the label of this block. 3486 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3487 3488 if (print_edges) 3489 OS << " "; 3490 3491 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3492 OS << L->getName(); 3493 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3494 OS << "case "; 3495 C->getLHS()->printPretty(OS, Helper, 3496 PrintingPolicy(Helper->getLangOpts())); 3497 if (C->getRHS()) { 3498 OS << " ... "; 3499 C->getRHS()->printPretty(OS, Helper, 3500 PrintingPolicy(Helper->getLangOpts())); 3501 } 3502 } else if (isa<DefaultStmt>(Label)) 3503 OS << "default"; 3504 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3505 OS << "catch ("; 3506 if (CS->getExceptionDecl()) 3507 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3508 0); 3509 else 3510 OS << "..."; 3511 OS << ")"; 3512 3513 } else 3514 llvm_unreachable("Invalid label statement in CFGBlock."); 3515 3516 OS << ":\n"; 3517 } 3518 3519 // Iterate through the statements in the block and print them. 3520 unsigned j = 1; 3521 3522 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3523 I != E ; ++I, ++j ) { 3524 3525 // Print the statement # in the basic block and the statement itself. 3526 if (print_edges) 3527 OS << " "; 3528 3529 OS << llvm::format("%3d", j) << ": "; 3530 3531 if (Helper) 3532 Helper->setStmtID(j); 3533 3534 print_elem(OS,Helper,*I); 3535 } 3536 3537 // Print the terminator of this block. 3538 if (B.getTerminator()) { 3539 if (print_edges) 3540 OS << " "; 3541 3542 OS << " T: "; 3543 3544 if (Helper) Helper->setBlockID(-1); 3545 3546 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3547 PrintingPolicy(Helper->getLangOpts())); 3548 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3549 OS << '\n'; 3550 } 3551 3552 if (print_edges) { 3553 // Print the predecessors of this block. 3554 OS << " Predecessors (" << B.pred_size() << "):"; 3555 unsigned i = 0; 3556 3557 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3558 I != E; ++I, ++i) { 3559 3560 if (i == 8 || (i-8) == 0) 3561 OS << "\n "; 3562 3563 OS << " B" << (*I)->getBlockID(); 3564 } 3565 3566 OS << '\n'; 3567 3568 // Print the successors of this block. 3569 OS << " Successors (" << B.succ_size() << "):"; 3570 i = 0; 3571 3572 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3573 I != E; ++I, ++i) { 3574 3575 if (i == 8 || (i-8) % 10 == 0) 3576 OS << "\n "; 3577 3578 if (*I) 3579 OS << " B" << (*I)->getBlockID(); 3580 else 3581 OS << " NULL"; 3582 } 3583 3584 OS << '\n'; 3585 } 3586} 3587 3588 3589/// dump - A simple pretty printer of a CFG that outputs to stderr. 3590void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3591 3592/// print - A simple pretty printer of a CFG that outputs to an ostream. 3593void CFG::print(raw_ostream &OS, const LangOptions &LO) const { 3594 StmtPrinterHelper Helper(this, LO); 3595 3596 // Print the entry block. 3597 print_block(OS, this, getEntry(), &Helper, true); 3598 3599 // Iterate through the CFGBlocks and print them one by one. 3600 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3601 // Skip the entry block, because we already printed it. 3602 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3603 continue; 3604 3605 print_block(OS, this, **I, &Helper, true); 3606 } 3607 3608 // Print the exit block. 3609 print_block(OS, this, getExit(), &Helper, true); 3610 OS.flush(); 3611} 3612 3613/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3614void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3615 print(llvm::errs(), cfg, LO); 3616} 3617 3618/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3619/// Generally this will only be called from CFG::print. 3620void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3621 const LangOptions &LO) const { 3622 StmtPrinterHelper Helper(cfg, LO); 3623 print_block(OS, cfg, *this, &Helper, true); 3624} 3625 3626/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3627void CFGBlock::printTerminator(raw_ostream &OS, 3628 const LangOptions &LO) const { 3629 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3630 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3631} 3632 3633Stmt *CFGBlock::getTerminatorCondition() { 3634 Stmt *Terminator = this->Terminator; 3635 if (!Terminator) 3636 return NULL; 3637 3638 Expr *E = NULL; 3639 3640 switch (Terminator->getStmtClass()) { 3641 default: 3642 break; 3643 3644 case Stmt::ForStmtClass: 3645 E = cast<ForStmt>(Terminator)->getCond(); 3646 break; 3647 3648 case Stmt::WhileStmtClass: 3649 E = cast<WhileStmt>(Terminator)->getCond(); 3650 break; 3651 3652 case Stmt::DoStmtClass: 3653 E = cast<DoStmt>(Terminator)->getCond(); 3654 break; 3655 3656 case Stmt::IfStmtClass: 3657 E = cast<IfStmt>(Terminator)->getCond(); 3658 break; 3659 3660 case Stmt::ChooseExprClass: 3661 E = cast<ChooseExpr>(Terminator)->getCond(); 3662 break; 3663 3664 case Stmt::IndirectGotoStmtClass: 3665 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3666 break; 3667 3668 case Stmt::SwitchStmtClass: 3669 E = cast<SwitchStmt>(Terminator)->getCond(); 3670 break; 3671 3672 case Stmt::BinaryConditionalOperatorClass: 3673 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3674 break; 3675 3676 case Stmt::ConditionalOperatorClass: 3677 E = cast<ConditionalOperator>(Terminator)->getCond(); 3678 break; 3679 3680 case Stmt::BinaryOperatorClass: // '&&' and '||' 3681 E = cast<BinaryOperator>(Terminator)->getLHS(); 3682 break; 3683 3684 case Stmt::ObjCForCollectionStmtClass: 3685 return Terminator; 3686 } 3687 3688 return E ? E->IgnoreParens() : NULL; 3689} 3690 3691//===----------------------------------------------------------------------===// 3692// CFG Graphviz Visualization 3693//===----------------------------------------------------------------------===// 3694 3695 3696#ifndef NDEBUG 3697static StmtPrinterHelper* GraphHelper; 3698#endif 3699 3700void CFG::viewCFG(const LangOptions &LO) const { 3701#ifndef NDEBUG 3702 StmtPrinterHelper H(this, LO); 3703 GraphHelper = &H; 3704 llvm::ViewGraph(this,"CFG"); 3705 GraphHelper = NULL; 3706#endif 3707} 3708 3709namespace llvm { 3710template<> 3711struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3712 3713 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3714 3715 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 3716 3717#ifndef NDEBUG 3718 std::string OutSStr; 3719 llvm::raw_string_ostream Out(OutSStr); 3720 print_block(Out,Graph, *Node, GraphHelper, false); 3721 std::string& OutStr = Out.str(); 3722 3723 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3724 3725 // Process string output to make it nicer... 3726 for (unsigned i = 0; i != OutStr.length(); ++i) 3727 if (OutStr[i] == '\n') { // Left justify 3728 OutStr[i] = '\\'; 3729 OutStr.insert(OutStr.begin()+i+1, 'l'); 3730 } 3731 3732 return OutStr; 3733#else 3734 return ""; 3735#endif 3736 } 3737}; 3738} // end namespace llvm 3739