CFG.cpp revision c8cfc74bdcc999828bc232294d937fb191940d5b
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "clang/AST/CharUnits.h" 21#include "llvm/Support/GraphWriter.h" 22#include "llvm/Support/Allocator.h" 23#include "llvm/Support/Format.h" 24#include "llvm/ADT/DenseMap.h" 25#include "llvm/ADT/SmallPtrSet.h" 26#include "llvm/ADT/OwningPtr.h" 27 28using namespace clang; 29 30namespace { 31 32static SourceLocation GetEndLoc(Decl *D) { 33 if (VarDecl *VD = dyn_cast<VarDecl>(D)) 34 if (Expr *Ex = VD->getInit()) 35 return Ex->getSourceRange().getEnd(); 36 return D->getLocation(); 37} 38 39class CFGBuilder; 40 41/// The CFG builder uses a recursive algorithm to build the CFG. When 42/// we process an expression, sometimes we know that we must add the 43/// subexpressions as block-level expressions. For example: 44/// 45/// exp1 || exp2 46/// 47/// When processing the '||' expression, we know that exp1 and exp2 48/// need to be added as block-level expressions, even though they 49/// might not normally need to be. AddStmtChoice records this 50/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 51/// the builder has an option not to add a subexpression as a 52/// block-level expression. 53/// 54class AddStmtChoice { 55public: 56 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 57 58 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 59 60 bool alwaysAdd(CFGBuilder &builder, 61 const Stmt *stmt) const; 62 63 /// Return a copy of this object, except with the 'always-add' bit 64 /// set as specified. 65 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 66 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 67 } 68 69private: 70 Kind kind; 71}; 72 73/// LocalScope - Node in tree of local scopes created for C++ implicit 74/// destructor calls generation. It contains list of automatic variables 75/// declared in the scope and link to position in previous scope this scope 76/// began in. 77/// 78/// The process of creating local scopes is as follows: 79/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 80/// - Before processing statements in scope (e.g. CompoundStmt) create 81/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 82/// and set CFGBuilder::ScopePos to the end of new scope, 83/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 84/// at this VarDecl, 85/// - For every normal (without jump) end of scope add to CFGBlock destructors 86/// for objects in the current scope, 87/// - For every jump add to CFGBlock destructors for objects 88/// between CFGBuilder::ScopePos and local scope position saved for jump 89/// target. Thanks to C++ restrictions on goto jumps we can be sure that 90/// jump target position will be on the path to root from CFGBuilder::ScopePos 91/// (adding any variable that doesn't need constructor to be called to 92/// LocalScope can break this assumption), 93/// 94class LocalScope { 95public: 96 typedef BumpVector<VarDecl*> AutomaticVarsTy; 97 98 /// const_iterator - Iterates local scope backwards and jumps to previous 99 /// scope on reaching the beginning of currently iterated scope. 100 class const_iterator { 101 const LocalScope* Scope; 102 103 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 104 /// Invalid iterator (with null Scope) has VarIter equal to 0. 105 unsigned VarIter; 106 107 public: 108 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 109 /// Incrementing invalid iterator is allowed and will result in invalid 110 /// iterator. 111 const_iterator() 112 : Scope(NULL), VarIter(0) {} 113 114 /// Create valid iterator. In case when S.Prev is an invalid iterator and 115 /// I is equal to 0, this will create invalid iterator. 116 const_iterator(const LocalScope& S, unsigned I) 117 : Scope(&S), VarIter(I) { 118 // Iterator to "end" of scope is not allowed. Handle it by going up 119 // in scopes tree possibly up to invalid iterator in the root. 120 if (VarIter == 0 && Scope) 121 *this = Scope->Prev; 122 } 123 124 VarDecl *const* operator->() const { 125 assert (Scope && "Dereferencing invalid iterator is not allowed"); 126 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 127 return &Scope->Vars[VarIter - 1]; 128 } 129 VarDecl *operator*() const { 130 return *this->operator->(); 131 } 132 133 const_iterator &operator++() { 134 if (!Scope) 135 return *this; 136 137 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 138 --VarIter; 139 if (VarIter == 0) 140 *this = Scope->Prev; 141 return *this; 142 } 143 const_iterator operator++(int) { 144 const_iterator P = *this; 145 ++*this; 146 return P; 147 } 148 149 bool operator==(const const_iterator &rhs) const { 150 return Scope == rhs.Scope && VarIter == rhs.VarIter; 151 } 152 bool operator!=(const const_iterator &rhs) const { 153 return !(*this == rhs); 154 } 155 156 operator bool() const { 157 return *this != const_iterator(); 158 } 159 160 int distance(const_iterator L); 161 }; 162 163 friend class const_iterator; 164 165private: 166 BumpVectorContext ctx; 167 168 /// Automatic variables in order of declaration. 169 AutomaticVarsTy Vars; 170 /// Iterator to variable in previous scope that was declared just before 171 /// begin of this scope. 172 const_iterator Prev; 173 174public: 175 /// Constructs empty scope linked to previous scope in specified place. 176 LocalScope(BumpVectorContext &ctx, const_iterator P) 177 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 178 179 /// Begin of scope in direction of CFG building (backwards). 180 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 181 182 void addVar(VarDecl *VD) { 183 Vars.push_back(VD, ctx); 184 } 185}; 186 187/// distance - Calculates distance from this to L. L must be reachable from this 188/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 189/// number of scopes between this and L. 190int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 191 int D = 0; 192 const_iterator F = *this; 193 while (F.Scope != L.Scope) { 194 assert (F != const_iterator() 195 && "L iterator is not reachable from F iterator."); 196 D += F.VarIter; 197 F = F.Scope->Prev; 198 } 199 D += F.VarIter - L.VarIter; 200 return D; 201} 202 203/// BlockScopePosPair - Structure for specifying position in CFG during its 204/// build process. It consists of CFGBlock that specifies position in CFG graph 205/// and LocalScope::const_iterator that specifies position in LocalScope graph. 206struct BlockScopePosPair { 207 BlockScopePosPair() : block(0) {} 208 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos) 209 : block(b), scopePosition(scopePos) {} 210 211 CFGBlock *block; 212 LocalScope::const_iterator scopePosition; 213}; 214 215/// TryResult - a class representing a variant over the values 216/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 217/// and is used by the CFGBuilder to decide if a branch condition 218/// can be decided up front during CFG construction. 219class TryResult { 220 int X; 221public: 222 TryResult(bool b) : X(b ? 1 : 0) {} 223 TryResult() : X(-1) {} 224 225 bool isTrue() const { return X == 1; } 226 bool isFalse() const { return X == 0; } 227 bool isKnown() const { return X >= 0; } 228 void negate() { 229 assert(isKnown()); 230 X ^= 0x1; 231 } 232}; 233 234/// CFGBuilder - This class implements CFG construction from an AST. 235/// The builder is stateful: an instance of the builder should be used to only 236/// construct a single CFG. 237/// 238/// Example usage: 239/// 240/// CFGBuilder builder; 241/// CFG* cfg = builder.BuildAST(stmt1); 242/// 243/// CFG construction is done via a recursive walk of an AST. We actually parse 244/// the AST in reverse order so that the successor of a basic block is 245/// constructed prior to its predecessor. This allows us to nicely capture 246/// implicit fall-throughs without extra basic blocks. 247/// 248class CFGBuilder { 249 typedef BlockScopePosPair JumpTarget; 250 typedef BlockScopePosPair JumpSource; 251 252 ASTContext *Context; 253 llvm::OwningPtr<CFG> cfg; 254 255 CFGBlock *Block; 256 CFGBlock *Succ; 257 JumpTarget ContinueJumpTarget; 258 JumpTarget BreakJumpTarget; 259 CFGBlock *SwitchTerminatedBlock; 260 CFGBlock *DefaultCaseBlock; 261 CFGBlock *TryTerminatedBlock; 262 263 // Current position in local scope. 264 LocalScope::const_iterator ScopePos; 265 266 // LabelMap records the mapping from Label expressions to their jump targets. 267 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 268 LabelMapTy LabelMap; 269 270 // A list of blocks that end with a "goto" that must be backpatched to their 271 // resolved targets upon completion of CFG construction. 272 typedef std::vector<JumpSource> BackpatchBlocksTy; 273 BackpatchBlocksTy BackpatchBlocks; 274 275 // A list of labels whose address has been taken (for indirect gotos). 276 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 277 LabelSetTy AddressTakenLabels; 278 279 bool badCFG; 280 const CFG::BuildOptions &BuildOpts; 281 282 // State to track for building switch statements. 283 bool switchExclusivelyCovered; 284 Expr::EvalResult *switchCond; 285 286 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 287 const Stmt *lastLookup; 288 289public: 290 explicit CFGBuilder(ASTContext *astContext, 291 const CFG::BuildOptions &buildOpts) 292 : Context(astContext), cfg(new CFG()), // crew a new CFG 293 Block(NULL), Succ(NULL), 294 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 295 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 296 switchExclusivelyCovered(false), switchCond(0), 297 cachedEntry(0), lastLookup(0) {} 298 299 // buildCFG - Used by external clients to construct the CFG. 300 CFG* buildCFG(const Decl *D, Stmt *Statement); 301 302 bool alwaysAdd(const Stmt *stmt); 303 304private: 305 // Visitors to walk an AST and construct the CFG. 306 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 307 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 308 CFGBlock *VisitBlockExpr(BlockExpr *E, AddStmtChoice asc); 309 CFGBlock *VisitBreakStmt(BreakStmt *B); 310 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 311 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 312 AddStmtChoice asc); 313 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 314 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 315 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 316 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 317 AddStmtChoice asc); 318 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 319 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 320 AddStmtChoice asc); 321 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 322 AddStmtChoice asc); 323 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 324 CFGBlock *VisitCaseStmt(CaseStmt *C); 325 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 326 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 327 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 328 AddStmtChoice asc); 329 CFGBlock *VisitContinueStmt(ContinueStmt *C); 330 CFGBlock *VisitDeclStmt(DeclStmt *DS); 331 CFGBlock *VisitDeclSubExpr(DeclStmt *DS); 332 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 333 CFGBlock *VisitDoStmt(DoStmt *D); 334 CFGBlock *VisitForStmt(ForStmt *F); 335 CFGBlock *VisitGotoStmt(GotoStmt *G); 336 CFGBlock *VisitIfStmt(IfStmt *I); 337 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 338 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 339 CFGBlock *VisitLabelStmt(LabelStmt *L); 340 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 341 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 342 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 343 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 344 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 345 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 346 CFGBlock *VisitReturnStmt(ReturnStmt *R); 347 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 348 AddStmtChoice asc); 349 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 350 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 351 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 352 CFGBlock *VisitWhileStmt(WhileStmt *W); 353 354 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 355 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 356 CFGBlock *VisitChildren(Stmt *S); 357 358 // Visitors to walk an AST and generate destructors of temporaries in 359 // full expression. 360 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 361 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 362 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 363 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 364 bool BindToTemporary); 365 CFGBlock * 366 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 367 bool BindToTemporary); 368 369 // NYS == Not Yet Supported 370 CFGBlock *NYS() { 371 badCFG = true; 372 return Block; 373 } 374 375 void autoCreateBlock() { if (!Block) Block = createBlock(); } 376 CFGBlock *createBlock(bool add_successor = true); 377 378 CFGBlock *addStmt(Stmt *S) { 379 return Visit(S, AddStmtChoice::AlwaysAdd); 380 } 381 CFGBlock *addInitializer(CXXCtorInitializer *I); 382 void addAutomaticObjDtors(LocalScope::const_iterator B, 383 LocalScope::const_iterator E, Stmt *S); 384 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 385 386 // Local scopes creation. 387 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 388 389 void addLocalScopeForStmt(Stmt *S); 390 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 391 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 392 393 void addLocalScopeAndDtors(Stmt *S); 394 395 // Interface to CFGBlock - adding CFGElements. 396 void appendStmt(CFGBlock *B, const Stmt *S) { 397 if (alwaysAdd(S) && cachedEntry) 398 cachedEntry->second = B; 399 400 // All block-level expressions should have already been IgnoreParens()ed. 401 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 402 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 403 } 404 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 405 B->appendInitializer(I, cfg->getBumpVectorContext()); 406 } 407 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 408 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 409 } 410 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 411 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 412 } 413 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 414 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 415 } 416 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 417 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 418 } 419 420 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 421 LocalScope::const_iterator B, LocalScope::const_iterator E); 422 423 void addSuccessor(CFGBlock *B, CFGBlock *S) { 424 B->addSuccessor(S, cfg->getBumpVectorContext()); 425 } 426 427 /// Try and evaluate an expression to an integer constant. 428 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 429 if (!BuildOpts.PruneTriviallyFalseEdges) 430 return false; 431 return !S->isTypeDependent() && 432 !S->isValueDependent() && 433 S->Evaluate(outResult, *Context); 434 } 435 436 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 437 /// if we can evaluate to a known value, otherwise return -1. 438 TryResult tryEvaluateBool(Expr *S) { 439 Expr::EvalResult Result; 440 if (!tryEvaluate(S, Result)) 441 return TryResult(); 442 443 if (Result.Val.isInt()) 444 return Result.Val.getInt().getBoolValue(); 445 446 if (Result.Val.isLValue()) { 447 const Expr *e = Result.Val.getLValueBase(); 448 const CharUnits &c = Result.Val.getLValueOffset(); 449 if (!e && c.isZero()) 450 return false; 451 } 452 return TryResult(); 453 } 454 455}; 456 457inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 458 const Stmt *stmt) const { 459 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 460} 461 462bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 463 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 464 465 if (!BuildOpts.forcedBlkExprs) 466 return shouldAdd; 467 468 if (lastLookup == stmt) { 469 if (cachedEntry) { 470 assert(cachedEntry->first == stmt); 471 return true; 472 } 473 return shouldAdd; 474 } 475 476 lastLookup = stmt; 477 478 // Perform the lookup! 479 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 480 481 if (!fb) { 482 // No need to update 'cachedEntry', since it will always be null. 483 assert(cachedEntry == 0); 484 return shouldAdd; 485 } 486 487 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 488 if (itr == fb->end()) { 489 cachedEntry = 0; 490 return shouldAdd; 491 } 492 493 cachedEntry = &*itr; 494 return true; 495} 496 497// FIXME: Add support for dependent-sized array types in C++? 498// Does it even make sense to build a CFG for an uninstantiated template? 499static const VariableArrayType *FindVA(const Type *t) { 500 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 501 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 502 if (vat->getSizeExpr()) 503 return vat; 504 505 t = vt->getElementType().getTypePtr(); 506 } 507 508 return 0; 509} 510 511/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 512/// arbitrary statement. Examples include a single expression or a function 513/// body (compound statement). The ownership of the returned CFG is 514/// transferred to the caller. If CFG construction fails, this method returns 515/// NULL. 516CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 517 assert(cfg.get()); 518 if (!Statement) 519 return NULL; 520 521 // Create an empty block that will serve as the exit block for the CFG. Since 522 // this is the first block added to the CFG, it will be implicitly registered 523 // as the exit block. 524 Succ = createBlock(); 525 assert(Succ == &cfg->getExit()); 526 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 527 528 if (BuildOpts.AddImplicitDtors) 529 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 530 addImplicitDtorsForDestructor(DD); 531 532 // Visit the statements and create the CFG. 533 CFGBlock *B = addStmt(Statement); 534 535 if (badCFG) 536 return NULL; 537 538 // For C++ constructor add initializers to CFG. 539 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 540 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 541 E = CD->init_rend(); I != E; ++I) { 542 B = addInitializer(*I); 543 if (badCFG) 544 return NULL; 545 } 546 } 547 548 if (B) 549 Succ = B; 550 551 // Backpatch the gotos whose label -> block mappings we didn't know when we 552 // encountered them. 553 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 554 E = BackpatchBlocks.end(); I != E; ++I ) { 555 556 CFGBlock *B = I->block; 557 GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 558 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 559 560 // If there is no target for the goto, then we are looking at an 561 // incomplete AST. Handle this by not registering a successor. 562 if (LI == LabelMap.end()) continue; 563 564 JumpTarget JT = LI->second; 565 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 566 JT.scopePosition); 567 addSuccessor(B, JT.block); 568 } 569 570 // Add successors to the Indirect Goto Dispatch block (if we have one). 571 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 572 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 573 E = AddressTakenLabels.end(); I != E; ++I ) { 574 575 // Lookup the target block. 576 LabelMapTy::iterator LI = LabelMap.find(*I); 577 578 // If there is no target block that contains label, then we are looking 579 // at an incomplete AST. Handle this by not registering a successor. 580 if (LI == LabelMap.end()) continue; 581 582 addSuccessor(B, LI->second.block); 583 } 584 585 // Create an empty entry block that has no predecessors. 586 cfg->setEntry(createBlock()); 587 588 return cfg.take(); 589} 590 591/// createBlock - Used to lazily create blocks that are connected 592/// to the current (global) succcessor. 593CFGBlock *CFGBuilder::createBlock(bool add_successor) { 594 CFGBlock *B = cfg->createBlock(); 595 if (add_successor && Succ) 596 addSuccessor(B, Succ); 597 return B; 598} 599 600/// addInitializer - Add C++ base or member initializer element to CFG. 601CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 602 if (!BuildOpts.AddInitializers) 603 return Block; 604 605 bool IsReference = false; 606 bool HasTemporaries = false; 607 608 // Destructors of temporaries in initialization expression should be called 609 // after initialization finishes. 610 Expr *Init = I->getInit(); 611 if (Init) { 612 if (FieldDecl *FD = I->getAnyMember()) 613 IsReference = FD->getType()->isReferenceType(); 614 HasTemporaries = isa<ExprWithCleanups>(Init); 615 616 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 617 // Generate destructors for temporaries in initialization expression. 618 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 619 IsReference); 620 } 621 } 622 623 autoCreateBlock(); 624 appendInitializer(Block, I); 625 626 if (Init) { 627 if (HasTemporaries) { 628 // For expression with temporaries go directly to subexpression to omit 629 // generating destructors for the second time. 630 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 631 } 632 return Visit(Init); 633 } 634 635 return Block; 636} 637 638/// addAutomaticObjDtors - Add to current block automatic objects destructors 639/// for objects in range of local scope positions. Use S as trigger statement 640/// for destructors. 641void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 642 LocalScope::const_iterator E, Stmt *S) { 643 if (!BuildOpts.AddImplicitDtors) 644 return; 645 646 if (B == E) 647 return; 648 649 CFGBlock::iterator InsertPos; 650 651 // We need to append the destructors in reverse order, but any one of them 652 // may be a no-return destructor which changes the CFG. As a result, buffer 653 // this sequence up and replay them in reverse order when appending onto the 654 // CFGBlock(s). 655 SmallVector<VarDecl*, 10> Decls; 656 Decls.reserve(B.distance(E)); 657 for (LocalScope::const_iterator I = B; I != E; ++I) 658 Decls.push_back(*I); 659 660 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 661 E = Decls.rend(); 662 I != E; ++I) { 663 // If this destructor is marked as a no-return destructor, we need to 664 // create a new block for the destructor which does not have as a successor 665 // anything built thus far: control won't flow out of this block. 666 QualType Ty = (*I)->getType().getNonReferenceType(); 667 if (const ArrayType *AT = Context->getAsArrayType(Ty)) 668 Ty = AT->getElementType(); 669 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 670 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) { 671 Block = createBlock(/*add_successor=*/false); 672 // Wire up this block directly to the exit block if we're in the 673 // no-return case. We pruned any other successors because control flow 674 // won't actually exit this block, but we want to be able to find all of 675 // these entries in the CFG when doing analyses. 676 addSuccessor(Block, &cfg->getExit()); 677 } else { 678 autoCreateBlock(); 679 } 680 681 appendAutomaticObjDtor(Block, *I, S); 682 } 683} 684 685/// addImplicitDtorsForDestructor - Add implicit destructors generated for 686/// base and member objects in destructor. 687void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 688 assert (BuildOpts.AddImplicitDtors 689 && "Can be called only when dtors should be added"); 690 const CXXRecordDecl *RD = DD->getParent(); 691 692 // At the end destroy virtual base objects. 693 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 694 VE = RD->vbases_end(); VI != VE; ++VI) { 695 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 696 if (!CD->hasTrivialDestructor()) { 697 autoCreateBlock(); 698 appendBaseDtor(Block, VI); 699 } 700 } 701 702 // Before virtual bases destroy direct base objects. 703 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 704 BE = RD->bases_end(); BI != BE; ++BI) { 705 if (!BI->isVirtual()) { 706 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 707 if (!CD->hasTrivialDestructor()) { 708 autoCreateBlock(); 709 appendBaseDtor(Block, BI); 710 } 711 } 712 } 713 714 // First destroy member objects. 715 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 716 FE = RD->field_end(); FI != FE; ++FI) { 717 // Check for constant size array. Set type to array element type. 718 QualType QT = FI->getType(); 719 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 720 if (AT->getSize() == 0) 721 continue; 722 QT = AT->getElementType(); 723 } 724 725 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 726 if (!CD->hasTrivialDestructor()) { 727 autoCreateBlock(); 728 appendMemberDtor(Block, *FI); 729 } 730 } 731} 732 733/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 734/// way return valid LocalScope object. 735LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 736 if (!Scope) { 737 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 738 Scope = alloc.Allocate<LocalScope>(); 739 BumpVectorContext ctx(alloc); 740 new (Scope) LocalScope(ctx, ScopePos); 741 } 742 return Scope; 743} 744 745/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 746/// that should create implicit scope (e.g. if/else substatements). 747void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 748 if (!BuildOpts.AddImplicitDtors) 749 return; 750 751 LocalScope *Scope = 0; 752 753 // For compound statement we will be creating explicit scope. 754 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 755 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 756 ; BI != BE; ++BI) { 757 Stmt *SI = (*BI)->stripLabelLikeStatements(); 758 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 759 Scope = addLocalScopeForDeclStmt(DS, Scope); 760 } 761 return; 762 } 763 764 // For any other statement scope will be implicit and as such will be 765 // interesting only for DeclStmt. 766 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 767 addLocalScopeForDeclStmt(DS); 768} 769 770/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 771/// reuse Scope if not NULL. 772LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 773 LocalScope* Scope) { 774 if (!BuildOpts.AddImplicitDtors) 775 return Scope; 776 777 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 778 ; DI != DE; ++DI) { 779 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 780 Scope = addLocalScopeForVarDecl(VD, Scope); 781 } 782 return Scope; 783} 784 785/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 786/// create add scope for automatic objects and temporary objects bound to 787/// const reference. Will reuse Scope if not NULL. 788LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 789 LocalScope* Scope) { 790 if (!BuildOpts.AddImplicitDtors) 791 return Scope; 792 793 // Check if variable is local. 794 switch (VD->getStorageClass()) { 795 case SC_None: 796 case SC_Auto: 797 case SC_Register: 798 break; 799 default: return Scope; 800 } 801 802 // Check for const references bound to temporary. Set type to pointee. 803 QualType QT = VD->getType(); 804 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 805 QT = RT->getPointeeType(); 806 if (!QT.isConstQualified()) 807 return Scope; 808 if (!VD->extendsLifetimeOfTemporary()) 809 return Scope; 810 } 811 812 // Check for constant size array. Set type to array element type. 813 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 814 if (AT->getSize() == 0) 815 return Scope; 816 QT = AT->getElementType(); 817 } 818 819 // Check if type is a C++ class with non-trivial destructor. 820 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 821 if (!CD->hasTrivialDestructor()) { 822 // Add the variable to scope 823 Scope = createOrReuseLocalScope(Scope); 824 Scope->addVar(VD); 825 ScopePos = Scope->begin(); 826 } 827 return Scope; 828} 829 830/// addLocalScopeAndDtors - For given statement add local scope for it and 831/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 832void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 833 if (!BuildOpts.AddImplicitDtors) 834 return; 835 836 LocalScope::const_iterator scopeBeginPos = ScopePos; 837 addLocalScopeForStmt(S); 838 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 839} 840 841/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 842/// variables with automatic storage duration to CFGBlock's elements vector. 843/// Elements will be prepended to physical beginning of the vector which 844/// happens to be logical end. Use blocks terminator as statement that specifies 845/// destructors call site. 846/// FIXME: This mechanism for adding automatic destructors doesn't handle 847/// no-return destructors properly. 848void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 849 LocalScope::const_iterator B, LocalScope::const_iterator E) { 850 BumpVectorContext &C = cfg->getBumpVectorContext(); 851 CFGBlock::iterator InsertPos 852 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 853 for (LocalScope::const_iterator I = B; I != E; ++I) 854 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 855 Blk->getTerminator()); 856} 857 858/// Visit - Walk the subtree of a statement and add extra 859/// blocks for ternary operators, &&, and ||. We also process "," and 860/// DeclStmts (which may contain nested control-flow). 861CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 862 if (!S) { 863 badCFG = true; 864 return 0; 865 } 866 867 if (Expr *E = dyn_cast<Expr>(S)) 868 S = E->IgnoreParens(); 869 870 switch (S->getStmtClass()) { 871 default: 872 return VisitStmt(S, asc); 873 874 case Stmt::AddrLabelExprClass: 875 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 876 877 case Stmt::BinaryConditionalOperatorClass: 878 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 879 880 case Stmt::BinaryOperatorClass: 881 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 882 883 case Stmt::BlockExprClass: 884 return VisitBlockExpr(cast<BlockExpr>(S), asc); 885 886 case Stmt::BreakStmtClass: 887 return VisitBreakStmt(cast<BreakStmt>(S)); 888 889 case Stmt::CallExprClass: 890 case Stmt::CXXOperatorCallExprClass: 891 case Stmt::CXXMemberCallExprClass: 892 return VisitCallExpr(cast<CallExpr>(S), asc); 893 894 case Stmt::CaseStmtClass: 895 return VisitCaseStmt(cast<CaseStmt>(S)); 896 897 case Stmt::ChooseExprClass: 898 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 899 900 case Stmt::CompoundStmtClass: 901 return VisitCompoundStmt(cast<CompoundStmt>(S)); 902 903 case Stmt::ConditionalOperatorClass: 904 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 905 906 case Stmt::ContinueStmtClass: 907 return VisitContinueStmt(cast<ContinueStmt>(S)); 908 909 case Stmt::CXXCatchStmtClass: 910 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 911 912 case Stmt::ExprWithCleanupsClass: 913 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 914 915 case Stmt::CXXBindTemporaryExprClass: 916 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 917 918 case Stmt::CXXConstructExprClass: 919 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 920 921 case Stmt::CXXFunctionalCastExprClass: 922 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 923 924 case Stmt::CXXTemporaryObjectExprClass: 925 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 926 927 case Stmt::CXXThrowExprClass: 928 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 929 930 case Stmt::CXXTryStmtClass: 931 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 932 933 case Stmt::CXXForRangeStmtClass: 934 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 935 936 case Stmt::DeclStmtClass: 937 return VisitDeclStmt(cast<DeclStmt>(S)); 938 939 case Stmt::DefaultStmtClass: 940 return VisitDefaultStmt(cast<DefaultStmt>(S)); 941 942 case Stmt::DoStmtClass: 943 return VisitDoStmt(cast<DoStmt>(S)); 944 945 case Stmt::ForStmtClass: 946 return VisitForStmt(cast<ForStmt>(S)); 947 948 case Stmt::GotoStmtClass: 949 return VisitGotoStmt(cast<GotoStmt>(S)); 950 951 case Stmt::IfStmtClass: 952 return VisitIfStmt(cast<IfStmt>(S)); 953 954 case Stmt::ImplicitCastExprClass: 955 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 956 957 case Stmt::IndirectGotoStmtClass: 958 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 959 960 case Stmt::LabelStmtClass: 961 return VisitLabelStmt(cast<LabelStmt>(S)); 962 963 case Stmt::MemberExprClass: 964 return VisitMemberExpr(cast<MemberExpr>(S), asc); 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::NullStmtClass: 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 Block = createBlock(!NoReturn); 1211 appendStmt(Block, C); 1212 1213 if (NoReturn) { 1214 // Wire this to the exit block directly. 1215 addSuccessor(Block, &cfg->getExit()); 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 Expr::EvalResult V1; 2342 CS->getLHS()->Evaluate(V1, Ctx); 2343 assert(V1.Val.isInt()); 2344 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2345 const llvm::APSInt &lhsInt = V1.Val.getInt(); 2346 2347 if (condInt == lhsInt) { 2348 addCase = true; 2349 switchExclusivelyCovered = true; 2350 } 2351 else if (condInt < lhsInt) { 2352 if (const Expr *RHS = CS->getRHS()) { 2353 // Evaluate the RHS of the case value. 2354 Expr::EvalResult V2; 2355 RHS->Evaluate(V2, Ctx); 2356 assert(V2.Val.isInt()); 2357 if (V2.Val.getInt() <= condInt) { 2358 addCase = true; 2359 switchExclusivelyCovered = true; 2360 } 2361 } 2362 } 2363 } 2364 else 2365 addCase = true; 2366 } 2367 return addCase; 2368} 2369 2370CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2371 // CaseStmts are essentially labels, so they are the first statement in a 2372 // block. 2373 CFGBlock *TopBlock = 0, *LastBlock = 0; 2374 2375 if (Stmt *Sub = CS->getSubStmt()) { 2376 // For deeply nested chains of CaseStmts, instead of doing a recursion 2377 // (which can blow out the stack), manually unroll and create blocks 2378 // along the way. 2379 while (isa<CaseStmt>(Sub)) { 2380 CFGBlock *currentBlock = createBlock(false); 2381 currentBlock->setLabel(CS); 2382 2383 if (TopBlock) 2384 addSuccessor(LastBlock, currentBlock); 2385 else 2386 TopBlock = currentBlock; 2387 2388 addSuccessor(SwitchTerminatedBlock, 2389 shouldAddCase(switchExclusivelyCovered, switchCond, 2390 CS, *Context) 2391 ? currentBlock : 0); 2392 2393 LastBlock = currentBlock; 2394 CS = cast<CaseStmt>(Sub); 2395 Sub = CS->getSubStmt(); 2396 } 2397 2398 addStmt(Sub); 2399 } 2400 2401 CFGBlock *CaseBlock = Block; 2402 if (!CaseBlock) 2403 CaseBlock = createBlock(); 2404 2405 // Cases statements partition blocks, so this is the top of the basic block we 2406 // were processing (the "case XXX:" is the label). 2407 CaseBlock->setLabel(CS); 2408 2409 if (badCFG) 2410 return 0; 2411 2412 // Add this block to the list of successors for the block with the switch 2413 // statement. 2414 assert(SwitchTerminatedBlock); 2415 addSuccessor(SwitchTerminatedBlock, 2416 shouldAddCase(switchExclusivelyCovered, switchCond, 2417 CS, *Context) 2418 ? CaseBlock : 0); 2419 2420 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2421 Block = NULL; 2422 2423 if (TopBlock) { 2424 addSuccessor(LastBlock, CaseBlock); 2425 Succ = TopBlock; 2426 } else { 2427 // This block is now the implicit successor of other blocks. 2428 Succ = CaseBlock; 2429 } 2430 2431 return Succ; 2432} 2433 2434CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2435 if (Terminator->getSubStmt()) 2436 addStmt(Terminator->getSubStmt()); 2437 2438 DefaultCaseBlock = Block; 2439 2440 if (!DefaultCaseBlock) 2441 DefaultCaseBlock = createBlock(); 2442 2443 // Default statements partition blocks, so this is the top of the basic block 2444 // we were processing (the "default:" is the label). 2445 DefaultCaseBlock->setLabel(Terminator); 2446 2447 if (badCFG) 2448 return 0; 2449 2450 // Unlike case statements, we don't add the default block to the successors 2451 // for the switch statement immediately. This is done when we finish 2452 // processing the switch statement. This allows for the default case 2453 // (including a fall-through to the code after the switch statement) to always 2454 // be the last successor of a switch-terminated block. 2455 2456 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2457 Block = NULL; 2458 2459 // This block is now the implicit successor of other blocks. 2460 Succ = DefaultCaseBlock; 2461 2462 return DefaultCaseBlock; 2463} 2464 2465CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2466 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2467 // current block. 2468 CFGBlock *TrySuccessor = NULL; 2469 2470 if (Block) { 2471 if (badCFG) 2472 return 0; 2473 TrySuccessor = Block; 2474 } else TrySuccessor = Succ; 2475 2476 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2477 2478 // Create a new block that will contain the try statement. 2479 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2480 // Add the terminator in the try block. 2481 NewTryTerminatedBlock->setTerminator(Terminator); 2482 2483 bool HasCatchAll = false; 2484 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2485 // The code after the try is the implicit successor. 2486 Succ = TrySuccessor; 2487 CXXCatchStmt *CS = Terminator->getHandler(h); 2488 if (CS->getExceptionDecl() == 0) { 2489 HasCatchAll = true; 2490 } 2491 Block = NULL; 2492 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2493 if (CatchBlock == 0) 2494 return 0; 2495 // Add this block to the list of successors for the block with the try 2496 // statement. 2497 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2498 } 2499 if (!HasCatchAll) { 2500 if (PrevTryTerminatedBlock) 2501 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2502 else 2503 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2504 } 2505 2506 // The code after the try is the implicit successor. 2507 Succ = TrySuccessor; 2508 2509 // Save the current "try" context. 2510 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2511 cfg->addTryDispatchBlock(TryTerminatedBlock); 2512 2513 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2514 Block = NULL; 2515 Block = addStmt(Terminator->getTryBlock()); 2516 return Block; 2517} 2518 2519CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2520 // CXXCatchStmt are treated like labels, so they are the first statement in a 2521 // block. 2522 2523 // Save local scope position because in case of exception variable ScopePos 2524 // won't be restored when traversing AST. 2525 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2526 2527 // Create local scope for possible exception variable. 2528 // Store scope position. Add implicit destructor. 2529 if (VarDecl *VD = CS->getExceptionDecl()) { 2530 LocalScope::const_iterator BeginScopePos = ScopePos; 2531 addLocalScopeForVarDecl(VD); 2532 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2533 } 2534 2535 if (CS->getHandlerBlock()) 2536 addStmt(CS->getHandlerBlock()); 2537 2538 CFGBlock *CatchBlock = Block; 2539 if (!CatchBlock) 2540 CatchBlock = createBlock(); 2541 2542 CatchBlock->setLabel(CS); 2543 2544 if (badCFG) 2545 return 0; 2546 2547 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2548 Block = NULL; 2549 2550 return CatchBlock; 2551} 2552 2553CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2554 // C++0x for-range statements are specified as [stmt.ranged]: 2555 // 2556 // { 2557 // auto && __range = range-init; 2558 // for ( auto __begin = begin-expr, 2559 // __end = end-expr; 2560 // __begin != __end; 2561 // ++__begin ) { 2562 // for-range-declaration = *__begin; 2563 // statement 2564 // } 2565 // } 2566 2567 // Save local scope position before the addition of the implicit variables. 2568 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2569 2570 // Create local scopes and destructors for range, begin and end variables. 2571 if (Stmt *Range = S->getRangeStmt()) 2572 addLocalScopeForStmt(Range); 2573 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2574 addLocalScopeForStmt(BeginEnd); 2575 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2576 2577 LocalScope::const_iterator ContinueScopePos = ScopePos; 2578 2579 // "for" is a control-flow statement. Thus we stop processing the current 2580 // block. 2581 CFGBlock *LoopSuccessor = NULL; 2582 if (Block) { 2583 if (badCFG) 2584 return 0; 2585 LoopSuccessor = Block; 2586 } else 2587 LoopSuccessor = Succ; 2588 2589 // Save the current value for the break targets. 2590 // All breaks should go to the code following the loop. 2591 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2592 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2593 2594 // The block for the __begin != __end expression. 2595 CFGBlock *ConditionBlock = createBlock(false); 2596 ConditionBlock->setTerminator(S); 2597 2598 // Now add the actual condition to the condition block. 2599 if (Expr *C = S->getCond()) { 2600 Block = ConditionBlock; 2601 CFGBlock *BeginConditionBlock = addStmt(C); 2602 if (badCFG) 2603 return 0; 2604 assert(BeginConditionBlock == ConditionBlock && 2605 "condition block in for-range was unexpectedly complex"); 2606 (void)BeginConditionBlock; 2607 } 2608 2609 // The condition block is the implicit successor for the loop body as well as 2610 // any code above the loop. 2611 Succ = ConditionBlock; 2612 2613 // See if this is a known constant. 2614 TryResult KnownVal(true); 2615 2616 if (S->getCond()) 2617 KnownVal = tryEvaluateBool(S->getCond()); 2618 2619 // Now create the loop body. 2620 { 2621 assert(S->getBody()); 2622 2623 // Save the current values for Block, Succ, and continue targets. 2624 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2625 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2626 2627 // Generate increment code in its own basic block. This is the target of 2628 // continue statements. 2629 Block = 0; 2630 Succ = addStmt(S->getInc()); 2631 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2632 2633 // The starting block for the loop increment is the block that should 2634 // represent the 'loop target' for looping back to the start of the loop. 2635 ContinueJumpTarget.block->setLoopTarget(S); 2636 2637 // Finish up the increment block and prepare to start the loop body. 2638 assert(Block); 2639 if (badCFG) 2640 return 0; 2641 Block = 0; 2642 2643 2644 // Add implicit scope and dtors for loop variable. 2645 addLocalScopeAndDtors(S->getLoopVarStmt()); 2646 2647 // Populate a new block to contain the loop body and loop variable. 2648 Block = addStmt(S->getBody()); 2649 if (badCFG) 2650 return 0; 2651 Block = addStmt(S->getLoopVarStmt()); 2652 if (badCFG) 2653 return 0; 2654 2655 // This new body block is a successor to our condition block. 2656 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : Block); 2657 } 2658 2659 // Link up the condition block with the code that follows the loop (the 2660 // false branch). 2661 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 2662 2663 // Add the initialization statements. 2664 Block = createBlock(); 2665 addStmt(S->getBeginEndStmt()); 2666 return addStmt(S->getRangeStmt()); 2667} 2668 2669CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2670 AddStmtChoice asc) { 2671 if (BuildOpts.AddImplicitDtors) { 2672 // If adding implicit destructors visit the full expression for adding 2673 // destructors of temporaries. 2674 VisitForTemporaryDtors(E->getSubExpr()); 2675 2676 // Full expression has to be added as CFGStmt so it will be sequenced 2677 // before destructors of it's temporaries. 2678 asc = asc.withAlwaysAdd(true); 2679 } 2680 return Visit(E->getSubExpr(), asc); 2681} 2682 2683CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2684 AddStmtChoice asc) { 2685 if (asc.alwaysAdd(*this, E)) { 2686 autoCreateBlock(); 2687 appendStmt(Block, E); 2688 2689 // We do not want to propagate the AlwaysAdd property. 2690 asc = asc.withAlwaysAdd(false); 2691 } 2692 return Visit(E->getSubExpr(), asc); 2693} 2694 2695CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2696 AddStmtChoice asc) { 2697 autoCreateBlock(); 2698 if (!C->isElidable()) 2699 appendStmt(Block, C); 2700 2701 return VisitChildren(C); 2702} 2703 2704CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2705 AddStmtChoice asc) { 2706 if (asc.alwaysAdd(*this, E)) { 2707 autoCreateBlock(); 2708 appendStmt(Block, E); 2709 // We do not want to propagate the AlwaysAdd property. 2710 asc = asc.withAlwaysAdd(false); 2711 } 2712 return Visit(E->getSubExpr(), asc); 2713} 2714 2715CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2716 AddStmtChoice asc) { 2717 autoCreateBlock(); 2718 appendStmt(Block, C); 2719 return VisitChildren(C); 2720} 2721 2722CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2723 AddStmtChoice asc) { 2724 if (asc.alwaysAdd(*this, E)) { 2725 autoCreateBlock(); 2726 appendStmt(Block, E); 2727 } 2728 return Visit(E->getSubExpr(), AddStmtChoice()); 2729} 2730 2731CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 2732 // Lazily create the indirect-goto dispatch block if there isn't one already. 2733 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 2734 2735 if (!IBlock) { 2736 IBlock = createBlock(false); 2737 cfg->setIndirectGotoBlock(IBlock); 2738 } 2739 2740 // IndirectGoto is a control-flow statement. Thus we stop processing the 2741 // current block and create a new one. 2742 if (badCFG) 2743 return 0; 2744 2745 Block = createBlock(false); 2746 Block->setTerminator(I); 2747 addSuccessor(Block, IBlock); 2748 return addStmt(I->getTarget()); 2749} 2750 2751CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2752tryAgain: 2753 if (!E) { 2754 badCFG = true; 2755 return NULL; 2756 } 2757 switch (E->getStmtClass()) { 2758 default: 2759 return VisitChildrenForTemporaryDtors(E); 2760 2761 case Stmt::BinaryOperatorClass: 2762 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2763 2764 case Stmt::CXXBindTemporaryExprClass: 2765 return VisitCXXBindTemporaryExprForTemporaryDtors( 2766 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2767 2768 case Stmt::BinaryConditionalOperatorClass: 2769 case Stmt::ConditionalOperatorClass: 2770 return VisitConditionalOperatorForTemporaryDtors( 2771 cast<AbstractConditionalOperator>(E), BindToTemporary); 2772 2773 case Stmt::ImplicitCastExprClass: 2774 // For implicit cast we want BindToTemporary to be passed further. 2775 E = cast<CastExpr>(E)->getSubExpr(); 2776 goto tryAgain; 2777 2778 case Stmt::ParenExprClass: 2779 E = cast<ParenExpr>(E)->getSubExpr(); 2780 goto tryAgain; 2781 2782 case Stmt::MaterializeTemporaryExprClass: 2783 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 2784 goto tryAgain; 2785 } 2786} 2787 2788CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2789 // When visiting children for destructors we want to visit them in reverse 2790 // order. Because there's no reverse iterator for children must to reverse 2791 // them in helper vector. 2792 typedef SmallVector<Stmt *, 4> ChildrenVect; 2793 ChildrenVect ChildrenRev; 2794 for (Stmt::child_range I = E->children(); I; ++I) { 2795 if (*I) ChildrenRev.push_back(*I); 2796 } 2797 2798 CFGBlock *B = Block; 2799 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2800 L = ChildrenRev.rend(); I != L; ++I) { 2801 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2802 B = R; 2803 } 2804 return B; 2805} 2806 2807CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2808 if (E->isLogicalOp()) { 2809 // Destructors for temporaries in LHS expression should be called after 2810 // those for RHS expression. Even if this will unnecessarily create a block, 2811 // this block will be used at least by the full expression. 2812 autoCreateBlock(); 2813 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2814 if (badCFG) 2815 return NULL; 2816 2817 Succ = ConfluenceBlock; 2818 Block = NULL; 2819 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2820 2821 if (RHSBlock) { 2822 if (badCFG) 2823 return NULL; 2824 2825 // If RHS expression did produce destructors we need to connect created 2826 // blocks to CFG in same manner as for binary operator itself. 2827 CFGBlock *LHSBlock = createBlock(false); 2828 LHSBlock->setTerminator(CFGTerminator(E, true)); 2829 2830 // For binary operator LHS block is before RHS in list of predecessors 2831 // of ConfluenceBlock. 2832 std::reverse(ConfluenceBlock->pred_begin(), 2833 ConfluenceBlock->pred_end()); 2834 2835 // See if this is a known constant. 2836 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2837 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2838 KnownVal.negate(); 2839 2840 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2841 // itself. 2842 if (E->getOpcode() == BO_LOr) { 2843 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2844 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2845 } else { 2846 assert (E->getOpcode() == BO_LAnd); 2847 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2848 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2849 } 2850 2851 Block = LHSBlock; 2852 return LHSBlock; 2853 } 2854 2855 Block = ConfluenceBlock; 2856 return ConfluenceBlock; 2857 } 2858 2859 if (E->isAssignmentOp()) { 2860 // For assignment operator (=) LHS expression is visited 2861 // before RHS expression. For destructors visit them in reverse order. 2862 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2863 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2864 return LHSBlock ? LHSBlock : RHSBlock; 2865 } 2866 2867 // For any other binary operator RHS expression is visited before 2868 // LHS expression (order of children). For destructors visit them in reverse 2869 // order. 2870 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2871 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2872 return RHSBlock ? RHSBlock : LHSBlock; 2873} 2874 2875CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2876 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2877 // First add destructors for temporaries in subexpression. 2878 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2879 if (!BindToTemporary) { 2880 // If lifetime of temporary is not prolonged (by assigning to constant 2881 // reference) add destructor for it. 2882 2883 // If the destructor is marked as a no-return destructor, we need to create 2884 // a new block for the destructor which does not have as a successor 2885 // anything built thus far. Control won't flow out of this block. 2886 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 2887 if (cast<FunctionType>(Dtor->getType())->getNoReturnAttr()) { 2888 Block = createBlock(/*add_successor=*/false); 2889 // Wire up this block directly to the exit block if we're in the 2890 // no-return case. We pruned any other successors because control flow 2891 // won't actually exit this block, but we want to be able to find all of 2892 // these entries in the CFG when doing analyses. 2893 addSuccessor(Block, &cfg->getExit()); 2894 } else { 2895 autoCreateBlock(); 2896 } 2897 2898 appendTemporaryDtor(Block, E); 2899 B = Block; 2900 } 2901 return B; 2902} 2903 2904CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2905 AbstractConditionalOperator *E, bool BindToTemporary) { 2906 // First add destructors for condition expression. Even if this will 2907 // unnecessarily create a block, this block will be used at least by the full 2908 // expression. 2909 autoCreateBlock(); 2910 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2911 if (badCFG) 2912 return NULL; 2913 if (BinaryConditionalOperator *BCO 2914 = dyn_cast<BinaryConditionalOperator>(E)) { 2915 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2916 if (badCFG) 2917 return NULL; 2918 } 2919 2920 // Try to add block with destructors for LHS expression. 2921 CFGBlock *LHSBlock = NULL; 2922 Succ = ConfluenceBlock; 2923 Block = NULL; 2924 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2925 if (badCFG) 2926 return NULL; 2927 2928 // Try to add block with destructors for RHS expression; 2929 Succ = ConfluenceBlock; 2930 Block = NULL; 2931 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2932 BindToTemporary); 2933 if (badCFG) 2934 return NULL; 2935 2936 if (!RHSBlock && !LHSBlock) { 2937 // If neither LHS nor RHS expression had temporaries to destroy don't create 2938 // more blocks. 2939 Block = ConfluenceBlock; 2940 return Block; 2941 } 2942 2943 Block = createBlock(false); 2944 Block->setTerminator(CFGTerminator(E, true)); 2945 2946 // See if this is a known constant. 2947 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2948 2949 if (LHSBlock) { 2950 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2951 } else if (KnownVal.isFalse()) { 2952 addSuccessor(Block, NULL); 2953 } else { 2954 addSuccessor(Block, ConfluenceBlock); 2955 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2956 } 2957 2958 if (!RHSBlock) 2959 RHSBlock = ConfluenceBlock; 2960 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2961 2962 return Block; 2963} 2964 2965} // end anonymous namespace 2966 2967/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2968/// no successors or predecessors. If this is the first block created in the 2969/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2970CFGBlock *CFG::createBlock() { 2971 bool first_block = begin() == end(); 2972 2973 // Create the block. 2974 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2975 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2976 Blocks.push_back(Mem, BlkBVC); 2977 2978 // If this is the first block, set it as the Entry and Exit. 2979 if (first_block) 2980 Entry = Exit = &back(); 2981 2982 // Return the block. 2983 return &back(); 2984} 2985 2986/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2987/// CFG is returned to the caller. 2988CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 2989 const BuildOptions &BO) { 2990 CFGBuilder Builder(C, BO); 2991 return Builder.buildCFG(D, Statement); 2992} 2993 2994const CXXDestructorDecl * 2995CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 2996 switch (getKind()) { 2997 case CFGElement::Invalid: 2998 case CFGElement::Statement: 2999 case CFGElement::Initializer: 3000 llvm_unreachable("getDestructorDecl should only be used with " 3001 "ImplicitDtors"); 3002 case CFGElement::AutomaticObjectDtor: { 3003 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 3004 QualType ty = var->getType(); 3005 ty = ty.getNonReferenceType(); 3006 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3007 ty = arrayType->getElementType(); 3008 } 3009 const RecordType *recordType = ty->getAs<RecordType>(); 3010 const CXXRecordDecl *classDecl = 3011 cast<CXXRecordDecl>(recordType->getDecl()); 3012 return classDecl->getDestructor(); 3013 } 3014 case CFGElement::TemporaryDtor: { 3015 const CXXBindTemporaryExpr *bindExpr = 3016 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 3017 const CXXTemporary *temp = bindExpr->getTemporary(); 3018 return temp->getDestructor(); 3019 } 3020 case CFGElement::BaseDtor: 3021 case CFGElement::MemberDtor: 3022 3023 // Not yet supported. 3024 return 0; 3025 } 3026 llvm_unreachable("getKind() returned bogus value"); 3027 return 0; 3028} 3029 3030bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3031 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 3032 QualType ty = cdecl->getType(); 3033 return cast<FunctionType>(ty)->getNoReturnAttr(); 3034 } 3035 return false; 3036} 3037 3038//===----------------------------------------------------------------------===// 3039// CFG: Queries for BlkExprs. 3040//===----------------------------------------------------------------------===// 3041 3042namespace { 3043 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3044} 3045 3046static void FindSubExprAssignments(const Stmt *S, 3047 llvm::SmallPtrSet<const Expr*,50>& Set) { 3048 if (!S) 3049 return; 3050 3051 for (Stmt::const_child_range I = S->children(); I; ++I) { 3052 const Stmt *child = *I; 3053 if (!child) 3054 continue; 3055 3056 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3057 if (B->isAssignmentOp()) Set.insert(B); 3058 3059 FindSubExprAssignments(child, Set); 3060 } 3061} 3062 3063static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3064 BlkExprMapTy* M = new BlkExprMapTy(); 3065 3066 // Look for assignments that are used as subexpressions. These are the only 3067 // assignments that we want to *possibly* register as a block-level 3068 // expression. Basically, if an assignment occurs both in a subexpression and 3069 // at the block-level, it is a block-level expression. 3070 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3071 3072 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3073 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3074 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 3075 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3076 3077 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3078 3079 // Iterate over the statements again on identify the Expr* and Stmt* at the 3080 // block-level that are block-level expressions. 3081 3082 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3083 const CFGStmt *CS = BI->getAs<CFGStmt>(); 3084 if (!CS) 3085 continue; 3086 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3087 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3088 3089 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3090 // Assignment expressions that are not nested within another 3091 // expression are really "statements" whose value is never used by 3092 // another expression. 3093 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3094 continue; 3095 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3096 // Special handling for statement expressions. The last statement in 3097 // the statement expression is also a block-level expr. 3098 const CompoundStmt *C = SE->getSubStmt(); 3099 if (!C->body_empty()) { 3100 const Stmt *Last = C->body_back(); 3101 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3102 Last = LastEx->IgnoreParens(); 3103 unsigned x = M->size(); 3104 (*M)[Last] = x; 3105 } 3106 } 3107 3108 unsigned x = M->size(); 3109 (*M)[Exp] = x; 3110 } 3111 } 3112 3113 // Look at terminators. The condition is a block-level expression. 3114 3115 Stmt *S = (*I)->getTerminatorCondition(); 3116 3117 if (S && M->find(S) == M->end()) { 3118 unsigned x = M->size(); 3119 (*M)[S] = x; 3120 } 3121 } 3122 3123 return M; 3124} 3125 3126CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3127 assert(S != NULL); 3128 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3129 3130 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3131 BlkExprMapTy::iterator I = M->find(S); 3132 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3133} 3134 3135unsigned CFG::getNumBlkExprs() { 3136 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3137 return M->size(); 3138 3139 // We assume callers interested in the number of BlkExprs will want 3140 // the map constructed if it doesn't already exist. 3141 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3142 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3143} 3144 3145//===----------------------------------------------------------------------===// 3146// Filtered walking of the CFG. 3147//===----------------------------------------------------------------------===// 3148 3149bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3150 const CFGBlock *From, const CFGBlock *To) { 3151 3152 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3153 // If the 'To' has no label or is labeled but the label isn't a 3154 // CaseStmt then filter this edge. 3155 if (const SwitchStmt *S = 3156 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3157 if (S->isAllEnumCasesCovered()) { 3158 const Stmt *L = To->getLabel(); 3159 if (!L || !isa<CaseStmt>(L)) 3160 return true; 3161 } 3162 } 3163 } 3164 3165 return false; 3166} 3167 3168//===----------------------------------------------------------------------===// 3169// Cleanup: CFG dstor. 3170//===----------------------------------------------------------------------===// 3171 3172CFG::~CFG() { 3173 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3174} 3175 3176//===----------------------------------------------------------------------===// 3177// CFG pretty printing 3178//===----------------------------------------------------------------------===// 3179 3180namespace { 3181 3182class StmtPrinterHelper : public PrinterHelper { 3183 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3184 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3185 StmtMapTy StmtMap; 3186 DeclMapTy DeclMap; 3187 signed currentBlock; 3188 unsigned currentStmt; 3189 const LangOptions &LangOpts; 3190public: 3191 3192 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3193 : currentBlock(0), currentStmt(0), LangOpts(LO) 3194 { 3195 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3196 unsigned j = 1; 3197 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3198 BI != BEnd; ++BI, ++j ) { 3199 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 3200 const Stmt *stmt= SE->getStmt(); 3201 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3202 StmtMap[stmt] = P; 3203 3204 switch (stmt->getStmtClass()) { 3205 case Stmt::DeclStmtClass: 3206 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3207 break; 3208 case Stmt::IfStmtClass: { 3209 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3210 if (var) 3211 DeclMap[var] = P; 3212 break; 3213 } 3214 case Stmt::ForStmtClass: { 3215 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3216 if (var) 3217 DeclMap[var] = P; 3218 break; 3219 } 3220 case Stmt::WhileStmtClass: { 3221 const VarDecl *var = 3222 cast<WhileStmt>(stmt)->getConditionVariable(); 3223 if (var) 3224 DeclMap[var] = P; 3225 break; 3226 } 3227 case Stmt::SwitchStmtClass: { 3228 const VarDecl *var = 3229 cast<SwitchStmt>(stmt)->getConditionVariable(); 3230 if (var) 3231 DeclMap[var] = P; 3232 break; 3233 } 3234 case Stmt::CXXCatchStmtClass: { 3235 const VarDecl *var = 3236 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3237 if (var) 3238 DeclMap[var] = P; 3239 break; 3240 } 3241 default: 3242 break; 3243 } 3244 } 3245 } 3246 } 3247 } 3248 3249 3250 virtual ~StmtPrinterHelper() {} 3251 3252 const LangOptions &getLangOpts() const { return LangOpts; } 3253 void setBlockID(signed i) { currentBlock = i; } 3254 void setStmtID(unsigned i) { currentStmt = i; } 3255 3256 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3257 StmtMapTy::iterator I = StmtMap.find(S); 3258 3259 if (I == StmtMap.end()) 3260 return false; 3261 3262 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3263 && I->second.second == currentStmt) { 3264 return false; 3265 } 3266 3267 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3268 return true; 3269 } 3270 3271 bool handleDecl(const Decl *D, raw_ostream &OS) { 3272 DeclMapTy::iterator I = DeclMap.find(D); 3273 3274 if (I == DeclMap.end()) 3275 return false; 3276 3277 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3278 && I->second.second == currentStmt) { 3279 return false; 3280 } 3281 3282 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3283 return true; 3284 } 3285}; 3286} // end anonymous namespace 3287 3288 3289namespace { 3290class CFGBlockTerminatorPrint 3291 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3292 3293 raw_ostream &OS; 3294 StmtPrinterHelper* Helper; 3295 PrintingPolicy Policy; 3296public: 3297 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3298 const PrintingPolicy &Policy) 3299 : OS(os), Helper(helper), Policy(Policy) {} 3300 3301 void VisitIfStmt(IfStmt *I) { 3302 OS << "if "; 3303 I->getCond()->printPretty(OS,Helper,Policy); 3304 } 3305 3306 // Default case. 3307 void VisitStmt(Stmt *Terminator) { 3308 Terminator->printPretty(OS, Helper, Policy); 3309 } 3310 3311 void VisitForStmt(ForStmt *F) { 3312 OS << "for (" ; 3313 if (F->getInit()) 3314 OS << "..."; 3315 OS << "; "; 3316 if (Stmt *C = F->getCond()) 3317 C->printPretty(OS, Helper, Policy); 3318 OS << "; "; 3319 if (F->getInc()) 3320 OS << "..."; 3321 OS << ")"; 3322 } 3323 3324 void VisitWhileStmt(WhileStmt *W) { 3325 OS << "while " ; 3326 if (Stmt *C = W->getCond()) 3327 C->printPretty(OS, Helper, Policy); 3328 } 3329 3330 void VisitDoStmt(DoStmt *D) { 3331 OS << "do ... while "; 3332 if (Stmt *C = D->getCond()) 3333 C->printPretty(OS, Helper, Policy); 3334 } 3335 3336 void VisitSwitchStmt(SwitchStmt *Terminator) { 3337 OS << "switch "; 3338 Terminator->getCond()->printPretty(OS, Helper, Policy); 3339 } 3340 3341 void VisitCXXTryStmt(CXXTryStmt *CS) { 3342 OS << "try ..."; 3343 } 3344 3345 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3346 C->getCond()->printPretty(OS, Helper, Policy); 3347 OS << " ? ... : ..."; 3348 } 3349 3350 void VisitChooseExpr(ChooseExpr *C) { 3351 OS << "__builtin_choose_expr( "; 3352 C->getCond()->printPretty(OS, Helper, Policy); 3353 OS << " )"; 3354 } 3355 3356 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3357 OS << "goto *"; 3358 I->getTarget()->printPretty(OS, Helper, Policy); 3359 } 3360 3361 void VisitBinaryOperator(BinaryOperator* B) { 3362 if (!B->isLogicalOp()) { 3363 VisitExpr(B); 3364 return; 3365 } 3366 3367 B->getLHS()->printPretty(OS, Helper, Policy); 3368 3369 switch (B->getOpcode()) { 3370 case BO_LOr: 3371 OS << " || ..."; 3372 return; 3373 case BO_LAnd: 3374 OS << " && ..."; 3375 return; 3376 default: 3377 assert(false && "Invalid logical operator."); 3378 } 3379 } 3380 3381 void VisitExpr(Expr *E) { 3382 E->printPretty(OS, Helper, Policy); 3383 } 3384}; 3385} // end anonymous namespace 3386 3387static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3388 const CFGElement &E) { 3389 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3390 const Stmt *S = CS->getStmt(); 3391 3392 if (Helper) { 3393 3394 // special printing for statement-expressions. 3395 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3396 const CompoundStmt *Sub = SE->getSubStmt(); 3397 3398 if (Sub->children()) { 3399 OS << "({ ... ; "; 3400 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3401 OS << " })\n"; 3402 return; 3403 } 3404 } 3405 // special printing for comma expressions. 3406 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3407 if (B->getOpcode() == BO_Comma) { 3408 OS << "... , "; 3409 Helper->handledStmt(B->getRHS(),OS); 3410 OS << '\n'; 3411 return; 3412 } 3413 } 3414 } 3415 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3416 3417 if (isa<CXXOperatorCallExpr>(S)) { 3418 OS << " (OperatorCall)"; 3419 } else if (isa<CXXBindTemporaryExpr>(S)) { 3420 OS << " (BindTemporary)"; 3421 } 3422 3423 // Expressions need a newline. 3424 if (isa<Expr>(S)) 3425 OS << '\n'; 3426 3427 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3428 const CXXCtorInitializer *I = IE->getInitializer(); 3429 if (I->isBaseInitializer()) 3430 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3431 else OS << I->getAnyMember()->getName(); 3432 3433 OS << "("; 3434 if (Expr *IE = I->getInit()) 3435 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3436 OS << ")"; 3437 3438 if (I->isBaseInitializer()) 3439 OS << " (Base initializer)\n"; 3440 else OS << " (Member initializer)\n"; 3441 3442 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3443 const VarDecl *VD = DE->getVarDecl(); 3444 Helper->handleDecl(VD, OS); 3445 3446 const Type* T = VD->getType().getTypePtr(); 3447 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3448 T = RT->getPointeeType().getTypePtr(); 3449 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3450 T = ET; 3451 3452 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3453 OS << " (Implicit destructor)\n"; 3454 3455 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3456 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3457 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3458 OS << " (Base object destructor)\n"; 3459 3460 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3461 const FieldDecl *FD = ME->getFieldDecl(); 3462 3463 const Type *T = FD->getType().getTypePtr(); 3464 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3465 T = ET; 3466 3467 OS << "this->" << FD->getName(); 3468 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3469 OS << " (Member object destructor)\n"; 3470 3471 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3472 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3473 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3474 OS << " (Temporary object destructor)\n"; 3475 } 3476} 3477 3478static void print_block(raw_ostream &OS, const CFG* cfg, 3479 const CFGBlock &B, 3480 StmtPrinterHelper* Helper, bool print_edges) { 3481 3482 if (Helper) Helper->setBlockID(B.getBlockID()); 3483 3484 // Print the header. 3485 OS << "\n [ B" << B.getBlockID(); 3486 3487 if (&B == &cfg->getEntry()) 3488 OS << " (ENTRY) ]\n"; 3489 else if (&B == &cfg->getExit()) 3490 OS << " (EXIT) ]\n"; 3491 else if (&B == cfg->getIndirectGotoBlock()) 3492 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3493 else 3494 OS << " ]\n"; 3495 3496 // Print the label of this block. 3497 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3498 3499 if (print_edges) 3500 OS << " "; 3501 3502 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3503 OS << L->getName(); 3504 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3505 OS << "case "; 3506 C->getLHS()->printPretty(OS, Helper, 3507 PrintingPolicy(Helper->getLangOpts())); 3508 if (C->getRHS()) { 3509 OS << " ... "; 3510 C->getRHS()->printPretty(OS, Helper, 3511 PrintingPolicy(Helper->getLangOpts())); 3512 } 3513 } else if (isa<DefaultStmt>(Label)) 3514 OS << "default"; 3515 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3516 OS << "catch ("; 3517 if (CS->getExceptionDecl()) 3518 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3519 0); 3520 else 3521 OS << "..."; 3522 OS << ")"; 3523 3524 } else 3525 assert(false && "Invalid label statement in CFGBlock."); 3526 3527 OS << ":\n"; 3528 } 3529 3530 // Iterate through the statements in the block and print them. 3531 unsigned j = 1; 3532 3533 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3534 I != E ; ++I, ++j ) { 3535 3536 // Print the statement # in the basic block and the statement itself. 3537 if (print_edges) 3538 OS << " "; 3539 3540 OS << llvm::format("%3d", j) << ": "; 3541 3542 if (Helper) 3543 Helper->setStmtID(j); 3544 3545 print_elem(OS,Helper,*I); 3546 } 3547 3548 // Print the terminator of this block. 3549 if (B.getTerminator()) { 3550 if (print_edges) 3551 OS << " "; 3552 3553 OS << " T: "; 3554 3555 if (Helper) Helper->setBlockID(-1); 3556 3557 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3558 PrintingPolicy(Helper->getLangOpts())); 3559 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3560 OS << '\n'; 3561 } 3562 3563 if (print_edges) { 3564 // Print the predecessors of this block. 3565 OS << " Predecessors (" << B.pred_size() << "):"; 3566 unsigned i = 0; 3567 3568 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3569 I != E; ++I, ++i) { 3570 3571 if (i == 8 || (i-8) == 0) 3572 OS << "\n "; 3573 3574 OS << " B" << (*I)->getBlockID(); 3575 } 3576 3577 OS << '\n'; 3578 3579 // Print the successors of this block. 3580 OS << " Successors (" << B.succ_size() << "):"; 3581 i = 0; 3582 3583 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3584 I != E; ++I, ++i) { 3585 3586 if (i == 8 || (i-8) % 10 == 0) 3587 OS << "\n "; 3588 3589 if (*I) 3590 OS << " B" << (*I)->getBlockID(); 3591 else 3592 OS << " NULL"; 3593 } 3594 3595 OS << '\n'; 3596 } 3597} 3598 3599 3600/// dump - A simple pretty printer of a CFG that outputs to stderr. 3601void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3602 3603/// print - A simple pretty printer of a CFG that outputs to an ostream. 3604void CFG::print(raw_ostream &OS, const LangOptions &LO) const { 3605 StmtPrinterHelper Helper(this, LO); 3606 3607 // Print the entry block. 3608 print_block(OS, this, getEntry(), &Helper, true); 3609 3610 // Iterate through the CFGBlocks and print them one by one. 3611 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3612 // Skip the entry block, because we already printed it. 3613 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3614 continue; 3615 3616 print_block(OS, this, **I, &Helper, true); 3617 } 3618 3619 // Print the exit block. 3620 print_block(OS, this, getExit(), &Helper, true); 3621 OS.flush(); 3622} 3623 3624/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3625void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3626 print(llvm::errs(), cfg, LO); 3627} 3628 3629/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3630/// Generally this will only be called from CFG::print. 3631void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3632 const LangOptions &LO) const { 3633 StmtPrinterHelper Helper(cfg, LO); 3634 print_block(OS, cfg, *this, &Helper, true); 3635} 3636 3637/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3638void CFGBlock::printTerminator(raw_ostream &OS, 3639 const LangOptions &LO) const { 3640 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3641 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3642} 3643 3644Stmt *CFGBlock::getTerminatorCondition() { 3645 Stmt *Terminator = this->Terminator; 3646 if (!Terminator) 3647 return NULL; 3648 3649 Expr *E = NULL; 3650 3651 switch (Terminator->getStmtClass()) { 3652 default: 3653 break; 3654 3655 case Stmt::ForStmtClass: 3656 E = cast<ForStmt>(Terminator)->getCond(); 3657 break; 3658 3659 case Stmt::WhileStmtClass: 3660 E = cast<WhileStmt>(Terminator)->getCond(); 3661 break; 3662 3663 case Stmt::DoStmtClass: 3664 E = cast<DoStmt>(Terminator)->getCond(); 3665 break; 3666 3667 case Stmt::IfStmtClass: 3668 E = cast<IfStmt>(Terminator)->getCond(); 3669 break; 3670 3671 case Stmt::ChooseExprClass: 3672 E = cast<ChooseExpr>(Terminator)->getCond(); 3673 break; 3674 3675 case Stmt::IndirectGotoStmtClass: 3676 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3677 break; 3678 3679 case Stmt::SwitchStmtClass: 3680 E = cast<SwitchStmt>(Terminator)->getCond(); 3681 break; 3682 3683 case Stmt::BinaryConditionalOperatorClass: 3684 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3685 break; 3686 3687 case Stmt::ConditionalOperatorClass: 3688 E = cast<ConditionalOperator>(Terminator)->getCond(); 3689 break; 3690 3691 case Stmt::BinaryOperatorClass: // '&&' and '||' 3692 E = cast<BinaryOperator>(Terminator)->getLHS(); 3693 break; 3694 3695 case Stmt::ObjCForCollectionStmtClass: 3696 return Terminator; 3697 } 3698 3699 return E ? E->IgnoreParens() : NULL; 3700} 3701 3702//===----------------------------------------------------------------------===// 3703// CFG Graphviz Visualization 3704//===----------------------------------------------------------------------===// 3705 3706 3707#ifndef NDEBUG 3708static StmtPrinterHelper* GraphHelper; 3709#endif 3710 3711void CFG::viewCFG(const LangOptions &LO) const { 3712#ifndef NDEBUG 3713 StmtPrinterHelper H(this, LO); 3714 GraphHelper = &H; 3715 llvm::ViewGraph(this,"CFG"); 3716 GraphHelper = NULL; 3717#endif 3718} 3719 3720namespace llvm { 3721template<> 3722struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3723 3724 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3725 3726 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 3727 3728#ifndef NDEBUG 3729 std::string OutSStr; 3730 llvm::raw_string_ostream Out(OutSStr); 3731 print_block(Out,Graph, *Node, GraphHelper, false); 3732 std::string& OutStr = Out.str(); 3733 3734 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3735 3736 // Process string output to make it nicer... 3737 for (unsigned i = 0; i != OutStr.length(); ++i) 3738 if (OutStr[i] == '\n') { // Left justify 3739 OutStr[i] = '\\'; 3740 OutStr.insert(OutStr.begin()+i+1, 'l'); 3741 } 3742 3743 return OutStr; 3744#else 3745 return ""; 3746#endif 3747 } 3748}; 3749} // end namespace llvm 3750