CFG.cpp revision 2794bc0e3757992194dd587d0f6a253ec72afc9a
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/CFG.h" 16#include "clang/AST/ASTContext.h" 17#include "clang/AST/Attr.h" 18#include "clang/AST/CharUnits.h" 19#include "clang/AST/DeclCXX.h" 20#include "clang/AST/PrettyPrinter.h" 21#include "clang/AST/StmtVisitor.h" 22#include "llvm/ADT/DenseMap.h" 23#include "llvm/ADT/OwningPtr.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/Support/Allocator.h" 26#include "llvm/Support/Format.h" 27#include "llvm/Support/GraphWriter.h" 28#include "llvm/Support/SaveAndRestore.h" 29 30using namespace clang; 31 32namespace { 33 34static SourceLocation GetEndLoc(Decl *D) { 35 if (VarDecl *VD = dyn_cast<VarDecl>(D)) 36 if (Expr *Ex = VD->getInit()) 37 return Ex->getSourceRange().getEnd(); 38 return D->getLocation(); 39} 40 41class CFGBuilder; 42 43/// The CFG builder uses a recursive algorithm to build the CFG. When 44/// we process an expression, sometimes we know that we must add the 45/// subexpressions as block-level expressions. For example: 46/// 47/// exp1 || exp2 48/// 49/// When processing the '||' expression, we know that exp1 and exp2 50/// need to be added as block-level expressions, even though they 51/// might not normally need to be. AddStmtChoice records this 52/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 53/// the builder has an option not to add a subexpression as a 54/// block-level expression. 55/// 56class AddStmtChoice { 57public: 58 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 59 60 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 61 62 bool alwaysAdd(CFGBuilder &builder, 63 const Stmt *stmt) const; 64 65 /// Return a copy of this object, except with the 'always-add' bit 66 /// set as specified. 67 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 68 return AddStmtChoice(alwaysAdd ? AlwaysAdd : NotAlwaysAdd); 69 } 70 71private: 72 Kind kind; 73}; 74 75/// LocalScope - Node in tree of local scopes created for C++ implicit 76/// destructor calls generation. It contains list of automatic variables 77/// declared in the scope and link to position in previous scope this scope 78/// began in. 79/// 80/// The process of creating local scopes is as follows: 81/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 82/// - Before processing statements in scope (e.g. CompoundStmt) create 83/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 84/// and set CFGBuilder::ScopePos to the end of new scope, 85/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 86/// at this VarDecl, 87/// - For every normal (without jump) end of scope add to CFGBlock destructors 88/// for objects in the current scope, 89/// - For every jump add to CFGBlock destructors for objects 90/// between CFGBuilder::ScopePos and local scope position saved for jump 91/// target. Thanks to C++ restrictions on goto jumps we can be sure that 92/// jump target position will be on the path to root from CFGBuilder::ScopePos 93/// (adding any variable that doesn't need constructor to be called to 94/// LocalScope can break this assumption), 95/// 96class LocalScope { 97public: 98 typedef BumpVector<VarDecl*> AutomaticVarsTy; 99 100 /// const_iterator - Iterates local scope backwards and jumps to previous 101 /// scope on reaching the beginning of currently iterated scope. 102 class const_iterator { 103 const LocalScope* Scope; 104 105 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 106 /// Invalid iterator (with null Scope) has VarIter equal to 0. 107 unsigned VarIter; 108 109 public: 110 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 111 /// Incrementing invalid iterator is allowed and will result in invalid 112 /// iterator. 113 const_iterator() 114 : Scope(NULL), VarIter(0) {} 115 116 /// Create valid iterator. In case when S.Prev is an invalid iterator and 117 /// I is equal to 0, this will create invalid iterator. 118 const_iterator(const LocalScope& S, unsigned I) 119 : Scope(&S), VarIter(I) { 120 // Iterator to "end" of scope is not allowed. Handle it by going up 121 // in scopes tree possibly up to invalid iterator in the root. 122 if (VarIter == 0 && Scope) 123 *this = Scope->Prev; 124 } 125 126 VarDecl *const* operator->() const { 127 assert (Scope && "Dereferencing invalid iterator is not allowed"); 128 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 129 return &Scope->Vars[VarIter - 1]; 130 } 131 VarDecl *operator*() const { 132 return *this->operator->(); 133 } 134 135 const_iterator &operator++() { 136 if (!Scope) 137 return *this; 138 139 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 140 --VarIter; 141 if (VarIter == 0) 142 *this = Scope->Prev; 143 return *this; 144 } 145 const_iterator operator++(int) { 146 const_iterator P = *this; 147 ++*this; 148 return P; 149 } 150 151 bool operator==(const const_iterator &rhs) const { 152 return Scope == rhs.Scope && VarIter == rhs.VarIter; 153 } 154 bool operator!=(const const_iterator &rhs) const { 155 return !(*this == rhs); 156 } 157 158 LLVM_EXPLICIT operator bool() const { 159 return *this != const_iterator(); 160 } 161 162 int distance(const_iterator L); 163 }; 164 165 friend class const_iterator; 166 167private: 168 BumpVectorContext ctx; 169 170 /// Automatic variables in order of declaration. 171 AutomaticVarsTy Vars; 172 /// Iterator to variable in previous scope that was declared just before 173 /// begin of this scope. 174 const_iterator Prev; 175 176public: 177 /// Constructs empty scope linked to previous scope in specified place. 178 LocalScope(BumpVectorContext &ctx, const_iterator P) 179 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 180 181 /// Begin of scope in direction of CFG building (backwards). 182 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 183 184 void addVar(VarDecl *VD) { 185 Vars.push_back(VD, ctx); 186 } 187}; 188 189/// distance - Calculates distance from this to L. L must be reachable from this 190/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 191/// number of scopes between this and L. 192int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 193 int D = 0; 194 const_iterator F = *this; 195 while (F.Scope != L.Scope) { 196 assert (F != const_iterator() 197 && "L iterator is not reachable from F iterator."); 198 D += F.VarIter; 199 F = F.Scope->Prev; 200 } 201 D += F.VarIter - L.VarIter; 202 return D; 203} 204 205/// BlockScopePosPair - Structure for specifying position in CFG during its 206/// build process. It consists of CFGBlock that specifies position in CFG graph 207/// and LocalScope::const_iterator that specifies position in LocalScope graph. 208struct BlockScopePosPair { 209 BlockScopePosPair() : block(0) {} 210 BlockScopePosPair(CFGBlock *b, LocalScope::const_iterator scopePos) 211 : block(b), scopePosition(scopePos) {} 212 213 CFGBlock *block; 214 LocalScope::const_iterator scopePosition; 215}; 216 217/// TryResult - a class representing a variant over the values 218/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 219/// and is used by the CFGBuilder to decide if a branch condition 220/// can be decided up front during CFG construction. 221class TryResult { 222 int X; 223public: 224 TryResult(bool b) : X(b ? 1 : 0) {} 225 TryResult() : X(-1) {} 226 227 bool isTrue() const { return X == 1; } 228 bool isFalse() const { return X == 0; } 229 bool isKnown() const { return X >= 0; } 230 void negate() { 231 assert(isKnown()); 232 X ^= 0x1; 233 } 234}; 235 236class reverse_children { 237 llvm::SmallVector<Stmt *, 12> childrenBuf; 238 ArrayRef<Stmt*> children; 239public: 240 reverse_children(Stmt *S); 241 242 typedef ArrayRef<Stmt*>::reverse_iterator iterator; 243 iterator begin() const { return children.rbegin(); } 244 iterator end() const { return children.rend(); } 245}; 246 247 248reverse_children::reverse_children(Stmt *S) { 249 if (CallExpr *CE = dyn_cast<CallExpr>(S)) { 250 children = CE->getRawSubExprs(); 251 return; 252 } 253 switch (S->getStmtClass()) { 254 // Note: Fill in this switch with more cases we want to optimize. 255 case Stmt::InitListExprClass: { 256 InitListExpr *IE = cast<InitListExpr>(S); 257 children = llvm::makeArrayRef(reinterpret_cast<Stmt**>(IE->getInits()), 258 IE->getNumInits()); 259 return; 260 } 261 default: 262 break; 263 } 264 265 // Default case for all other statements. 266 for (Stmt::child_range I = S->children(); I; ++I) { 267 childrenBuf.push_back(*I); 268 } 269 270 // This needs to be done *after* childrenBuf has been populated. 271 children = childrenBuf; 272} 273 274/// CFGBuilder - This class implements CFG construction from an AST. 275/// The builder is stateful: an instance of the builder should be used to only 276/// construct a single CFG. 277/// 278/// Example usage: 279/// 280/// CFGBuilder builder; 281/// CFG* cfg = builder.BuildAST(stmt1); 282/// 283/// CFG construction is done via a recursive walk of an AST. We actually parse 284/// the AST in reverse order so that the successor of a basic block is 285/// constructed prior to its predecessor. This allows us to nicely capture 286/// implicit fall-throughs without extra basic blocks. 287/// 288class CFGBuilder { 289 typedef BlockScopePosPair JumpTarget; 290 typedef BlockScopePosPair JumpSource; 291 292 ASTContext *Context; 293 OwningPtr<CFG> cfg; 294 295 CFGBlock *Block; 296 CFGBlock *Succ; 297 JumpTarget ContinueJumpTarget; 298 JumpTarget BreakJumpTarget; 299 CFGBlock *SwitchTerminatedBlock; 300 CFGBlock *DefaultCaseBlock; 301 CFGBlock *TryTerminatedBlock; 302 303 // Current position in local scope. 304 LocalScope::const_iterator ScopePos; 305 306 // LabelMap records the mapping from Label expressions to their jump targets. 307 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 308 LabelMapTy LabelMap; 309 310 // A list of blocks that end with a "goto" that must be backpatched to their 311 // resolved targets upon completion of CFG construction. 312 typedef std::vector<JumpSource> BackpatchBlocksTy; 313 BackpatchBlocksTy BackpatchBlocks; 314 315 // A list of labels whose address has been taken (for indirect gotos). 316 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 317 LabelSetTy AddressTakenLabels; 318 319 bool badCFG; 320 const CFG::BuildOptions &BuildOpts; 321 322 // State to track for building switch statements. 323 bool switchExclusivelyCovered; 324 Expr::EvalResult *switchCond; 325 326 CFG::BuildOptions::ForcedBlkExprs::value_type *cachedEntry; 327 const Stmt *lastLookup; 328 329 // Caches boolean evaluations of expressions to avoid multiple re-evaluations 330 // during construction of branches for chained logical operators. 331 typedef llvm::DenseMap<Expr *, TryResult> CachedBoolEvalsTy; 332 CachedBoolEvalsTy CachedBoolEvals; 333 334public: 335 explicit CFGBuilder(ASTContext *astContext, 336 const CFG::BuildOptions &buildOpts) 337 : Context(astContext), cfg(new CFG()), // crew a new CFG 338 Block(NULL), Succ(NULL), 339 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 340 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 341 switchExclusivelyCovered(false), switchCond(0), 342 cachedEntry(0), lastLookup(0) {} 343 344 // buildCFG - Used by external clients to construct the CFG. 345 CFG* buildCFG(const Decl *D, Stmt *Statement); 346 347 bool alwaysAdd(const Stmt *stmt); 348 349private: 350 // Visitors to walk an AST and construct the CFG. 351 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 352 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 353 CFGBlock *VisitBreakStmt(BreakStmt *B); 354 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 355 CFGBlock *VisitCaseStmt(CaseStmt *C); 356 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 357 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 358 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 359 AddStmtChoice asc); 360 CFGBlock *VisitContinueStmt(ContinueStmt *C); 361 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 362 AddStmtChoice asc); 363 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 364 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 365 CFGBlock *VisitCXXForRangeStmt(CXXForRangeStmt *S); 366 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 367 AddStmtChoice asc); 368 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 369 AddStmtChoice asc); 370 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 371 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 372 CFGBlock *VisitDeclStmt(DeclStmt *DS); 373 CFGBlock *VisitDeclSubExpr(DeclStmt *DS); 374 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 375 CFGBlock *VisitDoStmt(DoStmt *D); 376 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, AddStmtChoice asc); 377 CFGBlock *VisitForStmt(ForStmt *F); 378 CFGBlock *VisitGotoStmt(GotoStmt *G); 379 CFGBlock *VisitIfStmt(IfStmt *I); 380 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 381 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 382 CFGBlock *VisitLabelStmt(LabelStmt *L); 383 CFGBlock *VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc); 384 CFGBlock *VisitLogicalOperator(BinaryOperator *B); 385 std::pair<CFGBlock *, CFGBlock *> VisitLogicalOperator(BinaryOperator *B, 386 Stmt *Term, 387 CFGBlock *TrueBlock, 388 CFGBlock *FalseBlock); 389 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 390 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 391 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 392 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 393 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 394 CFGBlock *VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S); 395 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 396 CFGBlock *VisitPseudoObjectExpr(PseudoObjectExpr *E); 397 CFGBlock *VisitReturnStmt(ReturnStmt *R); 398 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 399 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 400 CFGBlock *VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 401 AddStmtChoice asc); 402 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 403 CFGBlock *VisitWhileStmt(WhileStmt *W); 404 405 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 406 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 407 CFGBlock *VisitChildren(Stmt *S); 408 CFGBlock *VisitNoRecurse(Expr *E, AddStmtChoice asc); 409 410 // Visitors to walk an AST and generate destructors of temporaries in 411 // full expression. 412 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 413 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 414 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 415 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 416 bool BindToTemporary); 417 CFGBlock * 418 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 419 bool BindToTemporary); 420 421 // NYS == Not Yet Supported 422 CFGBlock *NYS() { 423 badCFG = true; 424 return Block; 425 } 426 427 void autoCreateBlock() { if (!Block) Block = createBlock(); } 428 CFGBlock *createBlock(bool add_successor = true); 429 CFGBlock *createNoReturnBlock(); 430 431 CFGBlock *addStmt(Stmt *S) { 432 return Visit(S, AddStmtChoice::AlwaysAdd); 433 } 434 CFGBlock *addInitializer(CXXCtorInitializer *I); 435 void addAutomaticObjDtors(LocalScope::const_iterator B, 436 LocalScope::const_iterator E, Stmt *S); 437 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 438 439 // Local scopes creation. 440 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 441 442 void addLocalScopeForStmt(Stmt *S); 443 LocalScope* addLocalScopeForDeclStmt(DeclStmt *DS, LocalScope* Scope = NULL); 444 LocalScope* addLocalScopeForVarDecl(VarDecl *VD, LocalScope* Scope = NULL); 445 446 void addLocalScopeAndDtors(Stmt *S); 447 448 // Interface to CFGBlock - adding CFGElements. 449 void appendStmt(CFGBlock *B, const Stmt *S) { 450 if (alwaysAdd(S) && cachedEntry) 451 cachedEntry->second = B; 452 453 // All block-level expressions should have already been IgnoreParens()ed. 454 assert(!isa<Expr>(S) || cast<Expr>(S)->IgnoreParens() == S); 455 B->appendStmt(const_cast<Stmt*>(S), cfg->getBumpVectorContext()); 456 } 457 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 458 B->appendInitializer(I, cfg->getBumpVectorContext()); 459 } 460 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 461 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 462 } 463 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 464 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 465 } 466 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 467 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 468 } 469 void appendAutomaticObjDtor(CFGBlock *B, VarDecl *VD, Stmt *S) { 470 B->appendAutomaticObjDtor(VD, S, cfg->getBumpVectorContext()); 471 } 472 473 void prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 474 LocalScope::const_iterator B, LocalScope::const_iterator E); 475 476 void addSuccessor(CFGBlock *B, CFGBlock *S) { 477 B->addSuccessor(S, cfg->getBumpVectorContext()); 478 } 479 480 /// Try and evaluate an expression to an integer constant. 481 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 482 if (!BuildOpts.PruneTriviallyFalseEdges) 483 return false; 484 return !S->isTypeDependent() && 485 !S->isValueDependent() && 486 S->EvaluateAsRValue(outResult, *Context); 487 } 488 489 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 490 /// if we can evaluate to a known value, otherwise return -1. 491 TryResult tryEvaluateBool(Expr *S) { 492 if (!BuildOpts.PruneTriviallyFalseEdges || 493 S->isTypeDependent() || S->isValueDependent()) 494 return TryResult(); 495 496 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(S)) { 497 if (Bop->isLogicalOp()) { 498 // Check the cache first. 499 CachedBoolEvalsTy::iterator I = CachedBoolEvals.find(S); 500 if (I != CachedBoolEvals.end()) 501 return I->second; // already in map; 502 503 // Retrieve result at first, or the map might be updated. 504 TryResult Result = evaluateAsBooleanConditionNoCache(S); 505 CachedBoolEvals[S] = Result; // update or insert 506 return Result; 507 } 508 else { 509 switch (Bop->getOpcode()) { 510 default: break; 511 // For 'x & 0' and 'x * 0', we can determine that 512 // the value is always false. 513 case BO_Mul: 514 case BO_And: { 515 // If either operand is zero, we know the value 516 // must be false. 517 llvm::APSInt IntVal; 518 if (Bop->getLHS()->EvaluateAsInt(IntVal, *Context)) { 519 if (IntVal.getBoolValue() == false) { 520 return TryResult(false); 521 } 522 } 523 if (Bop->getRHS()->EvaluateAsInt(IntVal, *Context)) { 524 if (IntVal.getBoolValue() == false) { 525 return TryResult(false); 526 } 527 } 528 } 529 break; 530 } 531 } 532 } 533 534 return evaluateAsBooleanConditionNoCache(S); 535 } 536 537 /// \brief Evaluate as boolean \param E without using the cache. 538 TryResult evaluateAsBooleanConditionNoCache(Expr *E) { 539 if (BinaryOperator *Bop = dyn_cast<BinaryOperator>(E)) { 540 if (Bop->isLogicalOp()) { 541 TryResult LHS = tryEvaluateBool(Bop->getLHS()); 542 if (LHS.isKnown()) { 543 // We were able to evaluate the LHS, see if we can get away with not 544 // evaluating the RHS: 0 && X -> 0, 1 || X -> 1 545 if (LHS.isTrue() == (Bop->getOpcode() == BO_LOr)) 546 return LHS.isTrue(); 547 548 TryResult RHS = tryEvaluateBool(Bop->getRHS()); 549 if (RHS.isKnown()) { 550 if (Bop->getOpcode() == BO_LOr) 551 return LHS.isTrue() || RHS.isTrue(); 552 else 553 return LHS.isTrue() && RHS.isTrue(); 554 } 555 } else { 556 TryResult RHS = tryEvaluateBool(Bop->getRHS()); 557 if (RHS.isKnown()) { 558 // We can't evaluate the LHS; however, sometimes the result 559 // is determined by the RHS: X && 0 -> 0, X || 1 -> 1. 560 if (RHS.isTrue() == (Bop->getOpcode() == BO_LOr)) 561 return RHS.isTrue(); 562 } 563 } 564 565 return TryResult(); 566 } 567 } 568 569 bool Result; 570 if (E->EvaluateAsBooleanCondition(Result, *Context)) 571 return Result; 572 573 return TryResult(); 574 } 575 576}; 577 578inline bool AddStmtChoice::alwaysAdd(CFGBuilder &builder, 579 const Stmt *stmt) const { 580 return builder.alwaysAdd(stmt) || kind == AlwaysAdd; 581} 582 583bool CFGBuilder::alwaysAdd(const Stmt *stmt) { 584 bool shouldAdd = BuildOpts.alwaysAdd(stmt); 585 586 if (!BuildOpts.forcedBlkExprs) 587 return shouldAdd; 588 589 if (lastLookup == stmt) { 590 if (cachedEntry) { 591 assert(cachedEntry->first == stmt); 592 return true; 593 } 594 return shouldAdd; 595 } 596 597 lastLookup = stmt; 598 599 // Perform the lookup! 600 CFG::BuildOptions::ForcedBlkExprs *fb = *BuildOpts.forcedBlkExprs; 601 602 if (!fb) { 603 // No need to update 'cachedEntry', since it will always be null. 604 assert(cachedEntry == 0); 605 return shouldAdd; 606 } 607 608 CFG::BuildOptions::ForcedBlkExprs::iterator itr = fb->find(stmt); 609 if (itr == fb->end()) { 610 cachedEntry = 0; 611 return shouldAdd; 612 } 613 614 cachedEntry = &*itr; 615 return true; 616} 617 618// FIXME: Add support for dependent-sized array types in C++? 619// Does it even make sense to build a CFG for an uninstantiated template? 620static const VariableArrayType *FindVA(const Type *t) { 621 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 622 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 623 if (vat->getSizeExpr()) 624 return vat; 625 626 t = vt->getElementType().getTypePtr(); 627 } 628 629 return 0; 630} 631 632/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 633/// arbitrary statement. Examples include a single expression or a function 634/// body (compound statement). The ownership of the returned CFG is 635/// transferred to the caller. If CFG construction fails, this method returns 636/// NULL. 637CFG* CFGBuilder::buildCFG(const Decl *D, Stmt *Statement) { 638 assert(cfg.get()); 639 if (!Statement) 640 return NULL; 641 642 // Create an empty block that will serve as the exit block for the CFG. Since 643 // this is the first block added to the CFG, it will be implicitly registered 644 // as the exit block. 645 Succ = createBlock(); 646 assert(Succ == &cfg->getExit()); 647 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 648 649 if (BuildOpts.AddImplicitDtors) 650 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 651 addImplicitDtorsForDestructor(DD); 652 653 // Visit the statements and create the CFG. 654 CFGBlock *B = addStmt(Statement); 655 656 if (badCFG) 657 return NULL; 658 659 // For C++ constructor add initializers to CFG. 660 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 661 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 662 E = CD->init_rend(); I != E; ++I) { 663 B = addInitializer(*I); 664 if (badCFG) 665 return NULL; 666 } 667 } 668 669 if (B) 670 Succ = B; 671 672 // Backpatch the gotos whose label -> block mappings we didn't know when we 673 // encountered them. 674 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 675 E = BackpatchBlocks.end(); I != E; ++I ) { 676 677 CFGBlock *B = I->block; 678 const GotoStmt *G = cast<GotoStmt>(B->getTerminator()); 679 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 680 681 // If there is no target for the goto, then we are looking at an 682 // incomplete AST. Handle this by not registering a successor. 683 if (LI == LabelMap.end()) continue; 684 685 JumpTarget JT = LI->second; 686 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 687 JT.scopePosition); 688 addSuccessor(B, JT.block); 689 } 690 691 // Add successors to the Indirect Goto Dispatch block (if we have one). 692 if (CFGBlock *B = cfg->getIndirectGotoBlock()) 693 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 694 E = AddressTakenLabels.end(); I != E; ++I ) { 695 696 // Lookup the target block. 697 LabelMapTy::iterator LI = LabelMap.find(*I); 698 699 // If there is no target block that contains label, then we are looking 700 // at an incomplete AST. Handle this by not registering a successor. 701 if (LI == LabelMap.end()) continue; 702 703 addSuccessor(B, LI->second.block); 704 } 705 706 // Create an empty entry block that has no predecessors. 707 cfg->setEntry(createBlock()); 708 709 return cfg.take(); 710} 711 712/// createBlock - Used to lazily create blocks that are connected 713/// to the current (global) succcessor. 714CFGBlock *CFGBuilder::createBlock(bool add_successor) { 715 CFGBlock *B = cfg->createBlock(); 716 if (add_successor && Succ) 717 addSuccessor(B, Succ); 718 return B; 719} 720 721/// createNoReturnBlock - Used to create a block is a 'noreturn' point in the 722/// CFG. It is *not* connected to the current (global) successor, and instead 723/// directly tied to the exit block in order to be reachable. 724CFGBlock *CFGBuilder::createNoReturnBlock() { 725 CFGBlock *B = createBlock(false); 726 B->setHasNoReturnElement(); 727 addSuccessor(B, &cfg->getExit()); 728 return B; 729} 730 731/// addInitializer - Add C++ base or member initializer element to CFG. 732CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 733 if (!BuildOpts.AddInitializers) 734 return Block; 735 736 bool IsReference = false; 737 bool HasTemporaries = false; 738 739 // Destructors of temporaries in initialization expression should be called 740 // after initialization finishes. 741 Expr *Init = I->getInit(); 742 if (Init) { 743 if (FieldDecl *FD = I->getAnyMember()) 744 IsReference = FD->getType()->isReferenceType(); 745 HasTemporaries = isa<ExprWithCleanups>(Init); 746 747 if (BuildOpts.AddTemporaryDtors && HasTemporaries) { 748 // Generate destructors for temporaries in initialization expression. 749 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 750 IsReference); 751 } 752 } 753 754 autoCreateBlock(); 755 appendInitializer(Block, I); 756 757 if (Init) { 758 if (HasTemporaries) { 759 // For expression with temporaries go directly to subexpression to omit 760 // generating destructors for the second time. 761 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 762 } 763 return Visit(Init); 764 } 765 766 return Block; 767} 768 769/// \brief Retrieve the type of the temporary object whose lifetime was 770/// extended by a local reference with the given initializer. 771static QualType getReferenceInitTemporaryType(ASTContext &Context, 772 const Expr *Init) { 773 while (true) { 774 // Skip parentheses. 775 Init = Init->IgnoreParens(); 776 777 // Skip through cleanups. 778 if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(Init)) { 779 Init = EWC->getSubExpr(); 780 continue; 781 } 782 783 // Skip through the temporary-materialization expression. 784 if (const MaterializeTemporaryExpr *MTE 785 = dyn_cast<MaterializeTemporaryExpr>(Init)) { 786 Init = MTE->GetTemporaryExpr(); 787 continue; 788 } 789 790 // Skip derived-to-base and no-op casts. 791 if (const CastExpr *CE = dyn_cast<CastExpr>(Init)) { 792 if ((CE->getCastKind() == CK_DerivedToBase || 793 CE->getCastKind() == CK_UncheckedDerivedToBase || 794 CE->getCastKind() == CK_NoOp) && 795 Init->getType()->isRecordType()) { 796 Init = CE->getSubExpr(); 797 continue; 798 } 799 } 800 801 // Skip member accesses into rvalues. 802 if (const MemberExpr *ME = dyn_cast<MemberExpr>(Init)) { 803 if (!ME->isArrow() && ME->getBase()->isRValue()) { 804 Init = ME->getBase(); 805 continue; 806 } 807 } 808 809 break; 810 } 811 812 return Init->getType(); 813} 814 815/// addAutomaticObjDtors - Add to current block automatic objects destructors 816/// for objects in range of local scope positions. Use S as trigger statement 817/// for destructors. 818void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 819 LocalScope::const_iterator E, Stmt *S) { 820 if (!BuildOpts.AddImplicitDtors) 821 return; 822 823 if (B == E) 824 return; 825 826 // We need to append the destructors in reverse order, but any one of them 827 // may be a no-return destructor which changes the CFG. As a result, buffer 828 // this sequence up and replay them in reverse order when appending onto the 829 // CFGBlock(s). 830 SmallVector<VarDecl*, 10> Decls; 831 Decls.reserve(B.distance(E)); 832 for (LocalScope::const_iterator I = B; I != E; ++I) 833 Decls.push_back(*I); 834 835 for (SmallVectorImpl<VarDecl*>::reverse_iterator I = Decls.rbegin(), 836 E = Decls.rend(); 837 I != E; ++I) { 838 // If this destructor is marked as a no-return destructor, we need to 839 // create a new block for the destructor which does not have as a successor 840 // anything built thus far: control won't flow out of this block. 841 QualType Ty = (*I)->getType(); 842 if (Ty->isReferenceType()) { 843 Ty = getReferenceInitTemporaryType(*Context, (*I)->getInit()); 844 } 845 Ty = Context->getBaseElementType(Ty); 846 847 const CXXDestructorDecl *Dtor = Ty->getAsCXXRecordDecl()->getDestructor(); 848 if (Dtor->isNoReturn()) 849 Block = createNoReturnBlock(); 850 else 851 autoCreateBlock(); 852 853 appendAutomaticObjDtor(Block, *I, S); 854 } 855} 856 857/// addImplicitDtorsForDestructor - Add implicit destructors generated for 858/// base and member objects in destructor. 859void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 860 assert (BuildOpts.AddImplicitDtors 861 && "Can be called only when dtors should be added"); 862 const CXXRecordDecl *RD = DD->getParent(); 863 864 // At the end destroy virtual base objects. 865 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 866 VE = RD->vbases_end(); VI != VE; ++VI) { 867 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 868 if (!CD->hasTrivialDestructor()) { 869 autoCreateBlock(); 870 appendBaseDtor(Block, VI); 871 } 872 } 873 874 // Before virtual bases destroy direct base objects. 875 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 876 BE = RD->bases_end(); BI != BE; ++BI) { 877 if (!BI->isVirtual()) { 878 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 879 if (!CD->hasTrivialDestructor()) { 880 autoCreateBlock(); 881 appendBaseDtor(Block, BI); 882 } 883 } 884 } 885 886 // First destroy member objects. 887 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 888 FE = RD->field_end(); FI != FE; ++FI) { 889 // Check for constant size array. Set type to array element type. 890 QualType QT = FI->getType(); 891 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 892 if (AT->getSize() == 0) 893 continue; 894 QT = AT->getElementType(); 895 } 896 897 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 898 if (!CD->hasTrivialDestructor()) { 899 autoCreateBlock(); 900 appendMemberDtor(Block, *FI); 901 } 902 } 903} 904 905/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 906/// way return valid LocalScope object. 907LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 908 if (!Scope) { 909 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 910 Scope = alloc.Allocate<LocalScope>(); 911 BumpVectorContext ctx(alloc); 912 new (Scope) LocalScope(ctx, ScopePos); 913 } 914 return Scope; 915} 916 917/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 918/// that should create implicit scope (e.g. if/else substatements). 919void CFGBuilder::addLocalScopeForStmt(Stmt *S) { 920 if (!BuildOpts.AddImplicitDtors) 921 return; 922 923 LocalScope *Scope = 0; 924 925 // For compound statement we will be creating explicit scope. 926 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 927 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 928 ; BI != BE; ++BI) { 929 Stmt *SI = (*BI)->stripLabelLikeStatements(); 930 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 931 Scope = addLocalScopeForDeclStmt(DS, Scope); 932 } 933 return; 934 } 935 936 // For any other statement scope will be implicit and as such will be 937 // interesting only for DeclStmt. 938 if (DeclStmt *DS = dyn_cast<DeclStmt>(S->stripLabelLikeStatements())) 939 addLocalScopeForDeclStmt(DS); 940} 941 942/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 943/// reuse Scope if not NULL. 944LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt *DS, 945 LocalScope* Scope) { 946 if (!BuildOpts.AddImplicitDtors) 947 return Scope; 948 949 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 950 ; DI != DE; ++DI) { 951 if (VarDecl *VD = dyn_cast<VarDecl>(*DI)) 952 Scope = addLocalScopeForVarDecl(VD, Scope); 953 } 954 return Scope; 955} 956 957/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 958/// create add scope for automatic objects and temporary objects bound to 959/// const reference. Will reuse Scope if not NULL. 960LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl *VD, 961 LocalScope* Scope) { 962 if (!BuildOpts.AddImplicitDtors) 963 return Scope; 964 965 // Check if variable is local. 966 switch (VD->getStorageClass()) { 967 case SC_None: 968 case SC_Auto: 969 case SC_Register: 970 break; 971 default: return Scope; 972 } 973 974 // Check for const references bound to temporary. Set type to pointee. 975 QualType QT = VD->getType(); 976 if (QT.getTypePtr()->isReferenceType()) { 977 if (!VD->extendsLifetimeOfTemporary()) 978 return Scope; 979 980 QT = getReferenceInitTemporaryType(*Context, VD->getInit()); 981 } 982 983 // Check for constant size array. Set type to array element type. 984 while (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 985 if (AT->getSize() == 0) 986 return Scope; 987 QT = AT->getElementType(); 988 } 989 990 // Check if type is a C++ class with non-trivial destructor. 991 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 992 if (!CD->hasTrivialDestructor()) { 993 // Add the variable to scope 994 Scope = createOrReuseLocalScope(Scope); 995 Scope->addVar(VD); 996 ScopePos = Scope->begin(); 997 } 998 return Scope; 999} 1000 1001/// addLocalScopeAndDtors - For given statement add local scope for it and 1002/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 1003void CFGBuilder::addLocalScopeAndDtors(Stmt *S) { 1004 if (!BuildOpts.AddImplicitDtors) 1005 return; 1006 1007 LocalScope::const_iterator scopeBeginPos = ScopePos; 1008 addLocalScopeForStmt(S); 1009 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 1010} 1011 1012/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 1013/// variables with automatic storage duration to CFGBlock's elements vector. 1014/// Elements will be prepended to physical beginning of the vector which 1015/// happens to be logical end. Use blocks terminator as statement that specifies 1016/// destructors call site. 1017/// FIXME: This mechanism for adding automatic destructors doesn't handle 1018/// no-return destructors properly. 1019void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock *Blk, 1020 LocalScope::const_iterator B, LocalScope::const_iterator E) { 1021 BumpVectorContext &C = cfg->getBumpVectorContext(); 1022 CFGBlock::iterator InsertPos 1023 = Blk->beginAutomaticObjDtorsInsert(Blk->end(), B.distance(E), C); 1024 for (LocalScope::const_iterator I = B; I != E; ++I) 1025 InsertPos = Blk->insertAutomaticObjDtor(InsertPos, *I, 1026 Blk->getTerminator()); 1027} 1028 1029/// Visit - Walk the subtree of a statement and add extra 1030/// blocks for ternary operators, &&, and ||. We also process "," and 1031/// DeclStmts (which may contain nested control-flow). 1032CFGBlock *CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 1033 if (!S) { 1034 badCFG = true; 1035 return 0; 1036 } 1037 1038 if (Expr *E = dyn_cast<Expr>(S)) 1039 S = E->IgnoreParens(); 1040 1041 switch (S->getStmtClass()) { 1042 default: 1043 return VisitStmt(S, asc); 1044 1045 case Stmt::AddrLabelExprClass: 1046 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 1047 1048 case Stmt::BinaryConditionalOperatorClass: 1049 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 1050 1051 case Stmt::BinaryOperatorClass: 1052 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 1053 1054 case Stmt::BlockExprClass: 1055 return VisitNoRecurse(cast<Expr>(S), asc); 1056 1057 case Stmt::BreakStmtClass: 1058 return VisitBreakStmt(cast<BreakStmt>(S)); 1059 1060 case Stmt::CallExprClass: 1061 case Stmt::CXXOperatorCallExprClass: 1062 case Stmt::CXXMemberCallExprClass: 1063 case Stmt::UserDefinedLiteralClass: 1064 return VisitCallExpr(cast<CallExpr>(S), asc); 1065 1066 case Stmt::CaseStmtClass: 1067 return VisitCaseStmt(cast<CaseStmt>(S)); 1068 1069 case Stmt::ChooseExprClass: 1070 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 1071 1072 case Stmt::CompoundStmtClass: 1073 return VisitCompoundStmt(cast<CompoundStmt>(S)); 1074 1075 case Stmt::ConditionalOperatorClass: 1076 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 1077 1078 case Stmt::ContinueStmtClass: 1079 return VisitContinueStmt(cast<ContinueStmt>(S)); 1080 1081 case Stmt::CXXCatchStmtClass: 1082 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 1083 1084 case Stmt::ExprWithCleanupsClass: 1085 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 1086 1087 case Stmt::CXXDefaultArgExprClass: 1088 case Stmt::CXXDefaultInitExprClass: 1089 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the 1090 // called function's declaration, not by the caller. If we simply add 1091 // this expression to the CFG, we could end up with the same Expr 1092 // appearing multiple times. 1093 // PR13385 / <rdar://problem/12156507> 1094 // 1095 // It's likewise possible for multiple CXXDefaultInitExprs for the same 1096 // expression to be used in the same function (through aggregate 1097 // initialization). 1098 return VisitStmt(S, asc); 1099 1100 case Stmt::CXXBindTemporaryExprClass: 1101 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 1102 1103 case Stmt::CXXConstructExprClass: 1104 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 1105 1106 case Stmt::CXXFunctionalCastExprClass: 1107 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 1108 1109 case Stmt::CXXTemporaryObjectExprClass: 1110 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 1111 1112 case Stmt::CXXThrowExprClass: 1113 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 1114 1115 case Stmt::CXXTryStmtClass: 1116 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 1117 1118 case Stmt::CXXForRangeStmtClass: 1119 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 1120 1121 case Stmt::DeclStmtClass: 1122 return VisitDeclStmt(cast<DeclStmt>(S)); 1123 1124 case Stmt::DefaultStmtClass: 1125 return VisitDefaultStmt(cast<DefaultStmt>(S)); 1126 1127 case Stmt::DoStmtClass: 1128 return VisitDoStmt(cast<DoStmt>(S)); 1129 1130 case Stmt::ForStmtClass: 1131 return VisitForStmt(cast<ForStmt>(S)); 1132 1133 case Stmt::GotoStmtClass: 1134 return VisitGotoStmt(cast<GotoStmt>(S)); 1135 1136 case Stmt::IfStmtClass: 1137 return VisitIfStmt(cast<IfStmt>(S)); 1138 1139 case Stmt::ImplicitCastExprClass: 1140 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 1141 1142 case Stmt::IndirectGotoStmtClass: 1143 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 1144 1145 case Stmt::LabelStmtClass: 1146 return VisitLabelStmt(cast<LabelStmt>(S)); 1147 1148 case Stmt::LambdaExprClass: 1149 return VisitLambdaExpr(cast<LambdaExpr>(S), asc); 1150 1151 case Stmt::MemberExprClass: 1152 return VisitMemberExpr(cast<MemberExpr>(S), asc); 1153 1154 case Stmt::NullStmtClass: 1155 return Block; 1156 1157 case Stmt::ObjCAtCatchStmtClass: 1158 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 1159 1160 case Stmt::ObjCAutoreleasePoolStmtClass: 1161 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S)); 1162 1163 case Stmt::ObjCAtSynchronizedStmtClass: 1164 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 1165 1166 case Stmt::ObjCAtThrowStmtClass: 1167 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 1168 1169 case Stmt::ObjCAtTryStmtClass: 1170 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 1171 1172 case Stmt::ObjCForCollectionStmtClass: 1173 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 1174 1175 case Stmt::OpaqueValueExprClass: 1176 return Block; 1177 1178 case Stmt::PseudoObjectExprClass: 1179 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S)); 1180 1181 case Stmt::ReturnStmtClass: 1182 return VisitReturnStmt(cast<ReturnStmt>(S)); 1183 1184 case Stmt::UnaryExprOrTypeTraitExprClass: 1185 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 1186 asc); 1187 1188 case Stmt::StmtExprClass: 1189 return VisitStmtExpr(cast<StmtExpr>(S), asc); 1190 1191 case Stmt::SwitchStmtClass: 1192 return VisitSwitchStmt(cast<SwitchStmt>(S)); 1193 1194 case Stmt::UnaryOperatorClass: 1195 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 1196 1197 case Stmt::WhileStmtClass: 1198 return VisitWhileStmt(cast<WhileStmt>(S)); 1199 } 1200} 1201 1202CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1203 if (asc.alwaysAdd(*this, S)) { 1204 autoCreateBlock(); 1205 appendStmt(Block, S); 1206 } 1207 1208 return VisitChildren(S); 1209} 1210 1211/// VisitChildren - Visit the children of a Stmt. 1212CFGBlock *CFGBuilder::VisitChildren(Stmt *S) { 1213 CFGBlock *B = Block; 1214 1215 // Visit the children in their reverse order so that they appear in 1216 // left-to-right (natural) order in the CFG. 1217 reverse_children RChildren(S); 1218 for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end(); 1219 I != E; ++I) { 1220 if (Stmt *Child = *I) 1221 if (CFGBlock *R = Visit(Child)) 1222 B = R; 1223 } 1224 return B; 1225} 1226 1227CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1228 AddStmtChoice asc) { 1229 AddressTakenLabels.insert(A->getLabel()); 1230 1231 if (asc.alwaysAdd(*this, A)) { 1232 autoCreateBlock(); 1233 appendStmt(Block, A); 1234 } 1235 1236 return Block; 1237} 1238 1239CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1240 AddStmtChoice asc) { 1241 if (asc.alwaysAdd(*this, U)) { 1242 autoCreateBlock(); 1243 appendStmt(Block, U); 1244 } 1245 1246 return Visit(U->getSubExpr(), AddStmtChoice()); 1247} 1248 1249CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) { 1250 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1251 appendStmt(ConfluenceBlock, B); 1252 1253 if (badCFG) 1254 return 0; 1255 1256 return VisitLogicalOperator(B, 0, ConfluenceBlock, ConfluenceBlock).first; 1257} 1258 1259std::pair<CFGBlock*, CFGBlock*> 1260CFGBuilder::VisitLogicalOperator(BinaryOperator *B, 1261 Stmt *Term, 1262 CFGBlock *TrueBlock, 1263 CFGBlock *FalseBlock) { 1264 1265 // Introspect the RHS. If it is a nested logical operation, we recursively 1266 // build the CFG using this function. Otherwise, resort to default 1267 // CFG construction behavior. 1268 Expr *RHS = B->getRHS()->IgnoreParens(); 1269 CFGBlock *RHSBlock, *ExitBlock; 1270 1271 do { 1272 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS)) 1273 if (B_RHS->isLogicalOp()) { 1274 llvm::tie(RHSBlock, ExitBlock) = 1275 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock); 1276 break; 1277 } 1278 1279 // The RHS is not a nested logical operation. Don't push the terminator 1280 // down further, but instead visit RHS and construct the respective 1281 // pieces of the CFG, and link up the RHSBlock with the terminator 1282 // we have been provided. 1283 ExitBlock = RHSBlock = createBlock(false); 1284 1285 if (!Term) { 1286 assert(TrueBlock == FalseBlock); 1287 addSuccessor(RHSBlock, TrueBlock); 1288 } 1289 else { 1290 RHSBlock->setTerminator(Term); 1291 TryResult KnownVal = tryEvaluateBool(RHS); 1292 addSuccessor(RHSBlock, KnownVal.isFalse() ? NULL : TrueBlock); 1293 addSuccessor(RHSBlock, KnownVal.isTrue() ? NULL : FalseBlock); 1294 } 1295 1296 Block = RHSBlock; 1297 RHSBlock = addStmt(RHS); 1298 } 1299 while (false); 1300 1301 if (badCFG) 1302 return std::make_pair((CFGBlock*)0, (CFGBlock*)0); 1303 1304 // Generate the blocks for evaluating the LHS. 1305 Expr *LHS = B->getLHS()->IgnoreParens(); 1306 1307 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS)) 1308 if (B_LHS->isLogicalOp()) { 1309 if (B->getOpcode() == BO_LOr) 1310 FalseBlock = RHSBlock; 1311 else 1312 TrueBlock = RHSBlock; 1313 1314 // For the LHS, treat 'B' as the terminator that we want to sink 1315 // into the nested branch. The RHS always gets the top-most 1316 // terminator. 1317 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock); 1318 } 1319 1320 // Create the block evaluating the LHS. 1321 // This contains the '&&' or '||' as the terminator. 1322 CFGBlock *LHSBlock = createBlock(false); 1323 LHSBlock->setTerminator(B); 1324 1325 Block = LHSBlock; 1326 CFGBlock *EntryLHSBlock = addStmt(LHS); 1327 1328 if (badCFG) 1329 return std::make_pair((CFGBlock*)0, (CFGBlock*)0); 1330 1331 // See if this is a known constant. 1332 TryResult KnownVal = tryEvaluateBool(LHS); 1333 1334 // Now link the LHSBlock with RHSBlock. 1335 if (B->getOpcode() == BO_LOr) { 1336 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : TrueBlock); 1337 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : RHSBlock); 1338 } else { 1339 assert(B->getOpcode() == BO_LAnd); 1340 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1341 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : FalseBlock); 1342 } 1343 1344 return std::make_pair(EntryLHSBlock, ExitBlock); 1345} 1346 1347 1348CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1349 AddStmtChoice asc) { 1350 // && or || 1351 if (B->isLogicalOp()) 1352 return VisitLogicalOperator(B); 1353 1354 if (B->getOpcode() == BO_Comma) { // , 1355 autoCreateBlock(); 1356 appendStmt(Block, B); 1357 addStmt(B->getRHS()); 1358 return addStmt(B->getLHS()); 1359 } 1360 1361 if (B->isAssignmentOp()) { 1362 if (asc.alwaysAdd(*this, B)) { 1363 autoCreateBlock(); 1364 appendStmt(Block, B); 1365 } 1366 Visit(B->getLHS()); 1367 return Visit(B->getRHS()); 1368 } 1369 1370 if (asc.alwaysAdd(*this, B)) { 1371 autoCreateBlock(); 1372 appendStmt(Block, B); 1373 } 1374 1375 CFGBlock *RBlock = Visit(B->getRHS()); 1376 CFGBlock *LBlock = Visit(B->getLHS()); 1377 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1378 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1379 // return RBlock. Otherwise we'll incorrectly return NULL. 1380 return (LBlock ? LBlock : RBlock); 1381} 1382 1383CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) { 1384 if (asc.alwaysAdd(*this, E)) { 1385 autoCreateBlock(); 1386 appendStmt(Block, E); 1387 } 1388 return Block; 1389} 1390 1391CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1392 // "break" is a control-flow statement. Thus we stop processing the current 1393 // block. 1394 if (badCFG) 1395 return 0; 1396 1397 // Now create a new block that ends with the break statement. 1398 Block = createBlock(false); 1399 Block->setTerminator(B); 1400 1401 // If there is no target for the break, then we are looking at an incomplete 1402 // AST. This means that the CFG cannot be constructed. 1403 if (BreakJumpTarget.block) { 1404 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1405 addSuccessor(Block, BreakJumpTarget.block); 1406 } else 1407 badCFG = true; 1408 1409 1410 return Block; 1411} 1412 1413static bool CanThrow(Expr *E, ASTContext &Ctx) { 1414 QualType Ty = E->getType(); 1415 if (Ty->isFunctionPointerType()) 1416 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1417 else if (Ty->isBlockPointerType()) 1418 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1419 1420 const FunctionType *FT = Ty->getAs<FunctionType>(); 1421 if (FT) { 1422 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1423 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) && 1424 Proto->isNothrow(Ctx)) 1425 return false; 1426 } 1427 return true; 1428} 1429 1430CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1431 // Compute the callee type. 1432 QualType calleeType = C->getCallee()->getType(); 1433 if (calleeType == Context->BoundMemberTy) { 1434 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1435 1436 // We should only get a null bound type if processing a dependent 1437 // CFG. Recover by assuming nothing. 1438 if (!boundType.isNull()) calleeType = boundType; 1439 } 1440 1441 // If this is a call to a no-return function, this stops the block here. 1442 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1443 1444 bool AddEHEdge = false; 1445 1446 // Languages without exceptions are assumed to not throw. 1447 if (Context->getLangOpts().Exceptions) { 1448 if (BuildOpts.AddEHEdges) 1449 AddEHEdge = true; 1450 } 1451 1452 if (FunctionDecl *FD = C->getDirectCallee()) { 1453 if (FD->isNoReturn()) 1454 NoReturn = true; 1455 if (FD->hasAttr<NoThrowAttr>()) 1456 AddEHEdge = false; 1457 } 1458 1459 if (!CanThrow(C->getCallee(), *Context)) 1460 AddEHEdge = false; 1461 1462 if (!NoReturn && !AddEHEdge) 1463 return VisitStmt(C, asc.withAlwaysAdd(true)); 1464 1465 if (Block) { 1466 Succ = Block; 1467 if (badCFG) 1468 return 0; 1469 } 1470 1471 if (NoReturn) 1472 Block = createNoReturnBlock(); 1473 else 1474 Block = createBlock(); 1475 1476 appendStmt(Block, C); 1477 1478 if (AddEHEdge) { 1479 // Add exceptional edges. 1480 if (TryTerminatedBlock) 1481 addSuccessor(Block, TryTerminatedBlock); 1482 else 1483 addSuccessor(Block, &cfg->getExit()); 1484 } 1485 1486 return VisitChildren(C); 1487} 1488 1489CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1490 AddStmtChoice asc) { 1491 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1492 appendStmt(ConfluenceBlock, C); 1493 if (badCFG) 1494 return 0; 1495 1496 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1497 Succ = ConfluenceBlock; 1498 Block = NULL; 1499 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1500 if (badCFG) 1501 return 0; 1502 1503 Succ = ConfluenceBlock; 1504 Block = NULL; 1505 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1506 if (badCFG) 1507 return 0; 1508 1509 Block = createBlock(false); 1510 // See if this is a known constant. 1511 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1512 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1513 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1514 Block->setTerminator(C); 1515 return addStmt(C->getCond()); 1516} 1517 1518 1519CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1520 addLocalScopeAndDtors(C); 1521 CFGBlock *LastBlock = Block; 1522 1523 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1524 I != E; ++I ) { 1525 // If we hit a segment of code just containing ';' (NullStmts), we can 1526 // get a null block back. In such cases, just use the LastBlock 1527 if (CFGBlock *newBlock = addStmt(*I)) 1528 LastBlock = newBlock; 1529 1530 if (badCFG) 1531 return NULL; 1532 } 1533 1534 return LastBlock; 1535} 1536 1537CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1538 AddStmtChoice asc) { 1539 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1540 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1541 1542 // Create the confluence block that will "merge" the results of the ternary 1543 // expression. 1544 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1545 appendStmt(ConfluenceBlock, C); 1546 if (badCFG) 1547 return 0; 1548 1549 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1550 1551 // Create a block for the LHS expression if there is an LHS expression. A 1552 // GCC extension allows LHS to be NULL, causing the condition to be the 1553 // value that is returned instead. 1554 // e.g: x ?: y is shorthand for: x ? x : y; 1555 Succ = ConfluenceBlock; 1556 Block = NULL; 1557 CFGBlock *LHSBlock = 0; 1558 const Expr *trueExpr = C->getTrueExpr(); 1559 if (trueExpr != opaqueValue) { 1560 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1561 if (badCFG) 1562 return 0; 1563 Block = NULL; 1564 } 1565 else 1566 LHSBlock = ConfluenceBlock; 1567 1568 // Create the block for the RHS expression. 1569 Succ = ConfluenceBlock; 1570 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1571 if (badCFG) 1572 return 0; 1573 1574 // If the condition is a logical '&&' or '||', build a more accurate CFG. 1575 if (BinaryOperator *Cond = 1576 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens())) 1577 if (Cond->isLogicalOp()) 1578 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first; 1579 1580 // Create the block that will contain the condition. 1581 Block = createBlock(false); 1582 1583 // See if this is a known constant. 1584 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1585 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1586 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1587 Block->setTerminator(C); 1588 Expr *condExpr = C->getCond(); 1589 1590 if (opaqueValue) { 1591 // Run the condition expression if it's not trivially expressed in 1592 // terms of the opaque value (or if there is no opaque value). 1593 if (condExpr != opaqueValue) 1594 addStmt(condExpr); 1595 1596 // Before that, run the common subexpression if there was one. 1597 // At least one of this or the above will be run. 1598 return addStmt(BCO->getCommon()); 1599 } 1600 1601 return addStmt(condExpr); 1602} 1603 1604CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1605 // Check if the Decl is for an __label__. If so, elide it from the 1606 // CFG entirely. 1607 if (isa<LabelDecl>(*DS->decl_begin())) 1608 return Block; 1609 1610 // This case also handles static_asserts. 1611 if (DS->isSingleDecl()) 1612 return VisitDeclSubExpr(DS); 1613 1614 CFGBlock *B = 0; 1615 1616 // Build an individual DeclStmt for each decl. 1617 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(), 1618 E = DS->decl_rend(); 1619 I != E; ++I) { 1620 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1621 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1622 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1623 1624 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1625 // automatically freed with the CFG. 1626 DeclGroupRef DG(*I); 1627 Decl *D = *I; 1628 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1629 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1630 1631 // Append the fake DeclStmt to block. 1632 B = VisitDeclSubExpr(DSNew); 1633 } 1634 1635 return B; 1636} 1637 1638/// VisitDeclSubExpr - Utility method to add block-level expressions for 1639/// DeclStmts and initializers in them. 1640CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1641 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1642 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1643 1644 if (!VD) { 1645 // Of everything that can be declared in a DeclStmt, only VarDecls impact 1646 // runtime semantics. 1647 return Block; 1648 } 1649 1650 bool IsReference = false; 1651 bool HasTemporaries = false; 1652 1653 // Guard static initializers under a branch. 1654 CFGBlock *blockAfterStaticInit = 0; 1655 1656 if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) { 1657 // For static variables, we need to create a branch to track 1658 // whether or not they are initialized. 1659 if (Block) { 1660 Succ = Block; 1661 Block = 0; 1662 if (badCFG) 1663 return 0; 1664 } 1665 blockAfterStaticInit = Succ; 1666 } 1667 1668 // Destructors of temporaries in initialization expression should be called 1669 // after initialization finishes. 1670 Expr *Init = VD->getInit(); 1671 if (Init) { 1672 IsReference = VD->getType()->isReferenceType(); 1673 HasTemporaries = isa<ExprWithCleanups>(Init); 1674 1675 if (BuildOpts.AddTemporaryDtors && HasTemporaries) { 1676 // Generate destructors for temporaries in initialization expression. 1677 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1678 IsReference); 1679 } 1680 } 1681 1682 autoCreateBlock(); 1683 appendStmt(Block, DS); 1684 1685 // Keep track of the last non-null block, as 'Block' can be nulled out 1686 // if the initializer expression is something like a 'while' in a 1687 // statement-expression. 1688 CFGBlock *LastBlock = Block; 1689 1690 if (Init) { 1691 if (HasTemporaries) { 1692 // For expression with temporaries go directly to subexpression to omit 1693 // generating destructors for the second time. 1694 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init); 1695 if (CFGBlock *newBlock = Visit(EC->getSubExpr())) 1696 LastBlock = newBlock; 1697 } 1698 else { 1699 if (CFGBlock *newBlock = Visit(Init)) 1700 LastBlock = newBlock; 1701 } 1702 } 1703 1704 // If the type of VD is a VLA, then we must process its size expressions. 1705 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1706 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) { 1707 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr())) 1708 LastBlock = newBlock; 1709 } 1710 1711 // Remove variable from local scope. 1712 if (ScopePos && VD == *ScopePos) 1713 ++ScopePos; 1714 1715 CFGBlock *B = LastBlock; 1716 if (blockAfterStaticInit) { 1717 Succ = B; 1718 Block = createBlock(false); 1719 Block->setTerminator(DS); 1720 addSuccessor(Block, blockAfterStaticInit); 1721 addSuccessor(Block, B); 1722 B = Block; 1723 } 1724 1725 return B; 1726} 1727 1728CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1729 // We may see an if statement in the middle of a basic block, or it may be the 1730 // first statement we are processing. In either case, we create a new basic 1731 // block. First, we create the blocks for the then...else statements, and 1732 // then we create the block containing the if statement. If we were in the 1733 // middle of a block, we stop processing that block. That block is then the 1734 // implicit successor for the "then" and "else" clauses. 1735 1736 // Save local scope position because in case of condition variable ScopePos 1737 // won't be restored when traversing AST. 1738 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1739 1740 // Create local scope for possible condition variable. 1741 // Store scope position. Add implicit destructor. 1742 if (VarDecl *VD = I->getConditionVariable()) { 1743 LocalScope::const_iterator BeginScopePos = ScopePos; 1744 addLocalScopeForVarDecl(VD); 1745 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1746 } 1747 1748 // The block we were processing is now finished. Make it the successor 1749 // block. 1750 if (Block) { 1751 Succ = Block; 1752 if (badCFG) 1753 return 0; 1754 } 1755 1756 // Process the false branch. 1757 CFGBlock *ElseBlock = Succ; 1758 1759 if (Stmt *Else = I->getElse()) { 1760 SaveAndRestore<CFGBlock*> sv(Succ); 1761 1762 // NULL out Block so that the recursive call to Visit will 1763 // create a new basic block. 1764 Block = NULL; 1765 1766 // If branch is not a compound statement create implicit scope 1767 // and add destructors. 1768 if (!isa<CompoundStmt>(Else)) 1769 addLocalScopeAndDtors(Else); 1770 1771 ElseBlock = addStmt(Else); 1772 1773 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1774 ElseBlock = sv.get(); 1775 else if (Block) { 1776 if (badCFG) 1777 return 0; 1778 } 1779 } 1780 1781 // Process the true branch. 1782 CFGBlock *ThenBlock; 1783 { 1784 Stmt *Then = I->getThen(); 1785 assert(Then); 1786 SaveAndRestore<CFGBlock*> sv(Succ); 1787 Block = NULL; 1788 1789 // If branch is not a compound statement create implicit scope 1790 // and add destructors. 1791 if (!isa<CompoundStmt>(Then)) 1792 addLocalScopeAndDtors(Then); 1793 1794 ThenBlock = addStmt(Then); 1795 1796 if (!ThenBlock) { 1797 // We can reach here if the "then" body has all NullStmts. 1798 // Create an empty block so we can distinguish between true and false 1799 // branches in path-sensitive analyses. 1800 ThenBlock = createBlock(false); 1801 addSuccessor(ThenBlock, sv.get()); 1802 } else if (Block) { 1803 if (badCFG) 1804 return 0; 1805 } 1806 } 1807 1808 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by 1809 // having these handle the actual control-flow jump. Note that 1810 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)" 1811 // we resort to the old control-flow behavior. This special handling 1812 // removes infeasible paths from the control-flow graph by having the 1813 // control-flow transfer of '&&' or '||' go directly into the then/else 1814 // blocks directly. 1815 if (!I->getConditionVariable()) 1816 if (BinaryOperator *Cond = 1817 dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens())) 1818 if (Cond->isLogicalOp()) 1819 return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first; 1820 1821 // Now create a new block containing the if statement. 1822 Block = createBlock(false); 1823 1824 // Set the terminator of the new block to the If statement. 1825 Block->setTerminator(I); 1826 1827 // See if this is a known constant. 1828 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1829 1830 // Now add the successors. 1831 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1832 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1833 1834 // Add the condition as the last statement in the new block. This may create 1835 // new blocks as the condition may contain control-flow. Any newly created 1836 // blocks will be pointed to be "Block". 1837 CFGBlock *LastBlock = addStmt(I->getCond()); 1838 1839 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1840 // and the condition variable initialization to the CFG. 1841 if (VarDecl *VD = I->getConditionVariable()) { 1842 if (Expr *Init = VD->getInit()) { 1843 autoCreateBlock(); 1844 appendStmt(Block, I->getConditionVariableDeclStmt()); 1845 LastBlock = addStmt(Init); 1846 } 1847 } 1848 1849 return LastBlock; 1850} 1851 1852 1853CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1854 // If we were in the middle of a block we stop processing that block. 1855 // 1856 // NOTE: If a "return" appears in the middle of a block, this means that the 1857 // code afterwards is DEAD (unreachable). We still keep a basic block 1858 // for that code; a simple "mark-and-sweep" from the entry block will be 1859 // able to report such dead blocks. 1860 1861 // Create the new block. 1862 Block = createBlock(false); 1863 1864 // The Exit block is the only successor. 1865 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1866 addSuccessor(Block, &cfg->getExit()); 1867 1868 // Add the return statement to the block. This may create new blocks if R 1869 // contains control-flow (short-circuit operations). 1870 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1871} 1872 1873CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1874 // Get the block of the labeled statement. Add it to our map. 1875 addStmt(L->getSubStmt()); 1876 CFGBlock *LabelBlock = Block; 1877 1878 if (!LabelBlock) // This can happen when the body is empty, i.e. 1879 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1880 1881 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1882 "label already in map"); 1883 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1884 1885 // Labels partition blocks, so this is the end of the basic block we were 1886 // processing (L is the block's label). Because this is label (and we have 1887 // already processed the substatement) there is no extra control-flow to worry 1888 // about. 1889 LabelBlock->setLabel(L); 1890 if (badCFG) 1891 return 0; 1892 1893 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1894 Block = NULL; 1895 1896 // This block is now the implicit successor of other blocks. 1897 Succ = LabelBlock; 1898 1899 return LabelBlock; 1900} 1901 1902CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) { 1903 CFGBlock *LastBlock = VisitNoRecurse(E, asc); 1904 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(), 1905 et = E->capture_init_end(); it != et; ++it) { 1906 if (Expr *Init = *it) { 1907 CFGBlock *Tmp = Visit(Init); 1908 if (Tmp != 0) 1909 LastBlock = Tmp; 1910 } 1911 } 1912 return LastBlock; 1913} 1914 1915CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1916 // Goto is a control-flow statement. Thus we stop processing the current 1917 // block and create a new one. 1918 1919 Block = createBlock(false); 1920 Block->setTerminator(G); 1921 1922 // If we already know the mapping to the label block add the successor now. 1923 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1924 1925 if (I == LabelMap.end()) 1926 // We will need to backpatch this block later. 1927 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1928 else { 1929 JumpTarget JT = I->second; 1930 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1931 addSuccessor(Block, JT.block); 1932 } 1933 1934 return Block; 1935} 1936 1937CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1938 CFGBlock *LoopSuccessor = NULL; 1939 1940 // Save local scope position because in case of condition variable ScopePos 1941 // won't be restored when traversing AST. 1942 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1943 1944 // Create local scope for init statement and possible condition variable. 1945 // Add destructor for init statement and condition variable. 1946 // Store scope position for continue statement. 1947 if (Stmt *Init = F->getInit()) 1948 addLocalScopeForStmt(Init); 1949 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1950 1951 if (VarDecl *VD = F->getConditionVariable()) 1952 addLocalScopeForVarDecl(VD); 1953 LocalScope::const_iterator ContinueScopePos = ScopePos; 1954 1955 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1956 1957 // "for" is a control-flow statement. Thus we stop processing the current 1958 // block. 1959 if (Block) { 1960 if (badCFG) 1961 return 0; 1962 LoopSuccessor = Block; 1963 } else 1964 LoopSuccessor = Succ; 1965 1966 // Save the current value for the break targets. 1967 // All breaks should go to the code following the loop. 1968 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1969 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1970 1971 CFGBlock *BodyBlock = 0, *TransitionBlock = 0; 1972 1973 // Now create the loop body. 1974 { 1975 assert(F->getBody()); 1976 1977 // Save the current values for Block, Succ, continue and break targets. 1978 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1979 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1980 1981 // Create an empty block to represent the transition block for looping back 1982 // to the head of the loop. If we have increment code, it will 1983 // go in this block as well. 1984 Block = Succ = TransitionBlock = createBlock(false); 1985 TransitionBlock->setLoopTarget(F); 1986 1987 if (Stmt *I = F->getInc()) { 1988 // Generate increment code in its own basic block. This is the target of 1989 // continue statements. 1990 Succ = addStmt(I); 1991 } 1992 1993 // Finish up the increment (or empty) block if it hasn't been already. 1994 if (Block) { 1995 assert(Block == Succ); 1996 if (badCFG) 1997 return 0; 1998 Block = 0; 1999 } 2000 2001 // The starting block for the loop increment is the block that should 2002 // represent the 'loop target' for looping back to the start of the loop. 2003 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2004 ContinueJumpTarget.block->setLoopTarget(F); 2005 2006 // Loop body should end with destructor of Condition variable (if any). 2007 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 2008 2009 // If body is not a compound statement create implicit scope 2010 // and add destructors. 2011 if (!isa<CompoundStmt>(F->getBody())) 2012 addLocalScopeAndDtors(F->getBody()); 2013 2014 // Now populate the body block, and in the process create new blocks as we 2015 // walk the body of the loop. 2016 BodyBlock = addStmt(F->getBody()); 2017 2018 if (!BodyBlock) { 2019 // In the case of "for (...;...;...);" we can have a null BodyBlock. 2020 // Use the continue jump target as the proxy for the body. 2021 BodyBlock = ContinueJumpTarget.block; 2022 } 2023 else if (badCFG) 2024 return 0; 2025 } 2026 2027 // Because of short-circuit evaluation, the condition of the loop can span 2028 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2029 // evaluate the condition. 2030 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0; 2031 2032 do { 2033 Expr *C = F->getCond(); 2034 2035 // Specially handle logical operators, which have a slightly 2036 // more optimal CFG representation. 2037 if (BinaryOperator *Cond = 2038 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : 0)) 2039 if (Cond->isLogicalOp()) { 2040 llvm::tie(EntryConditionBlock, ExitConditionBlock) = 2041 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor); 2042 break; 2043 } 2044 2045 // The default case when not handling logical operators. 2046 EntryConditionBlock = ExitConditionBlock = createBlock(false); 2047 ExitConditionBlock->setTerminator(F); 2048 2049 // See if this is a known constant. 2050 TryResult KnownVal(true); 2051 2052 if (C) { 2053 // Now add the actual condition to the condition block. 2054 // Because the condition itself may contain control-flow, new blocks may 2055 // be created. Thus we update "Succ" after adding the condition. 2056 Block = ExitConditionBlock; 2057 EntryConditionBlock = addStmt(C); 2058 2059 // If this block contains a condition variable, add both the condition 2060 // variable and initializer to the CFG. 2061 if (VarDecl *VD = F->getConditionVariable()) { 2062 if (Expr *Init = VD->getInit()) { 2063 autoCreateBlock(); 2064 appendStmt(Block, F->getConditionVariableDeclStmt()); 2065 EntryConditionBlock = addStmt(Init); 2066 assert(Block == EntryConditionBlock); 2067 } 2068 } 2069 2070 if (Block && badCFG) 2071 return 0; 2072 2073 KnownVal = tryEvaluateBool(C); 2074 } 2075 2076 // Add the loop body entry as a successor to the condition. 2077 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2078 // Link up the condition block with the code that follows the loop. (the 2079 // false branch). 2080 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2081 2082 } while (false); 2083 2084 // Link up the loop-back block to the entry condition block. 2085 addSuccessor(TransitionBlock, EntryConditionBlock); 2086 2087 // The condition block is the implicit successor for any code above the loop. 2088 Succ = EntryConditionBlock; 2089 2090 // If the loop contains initialization, create a new block for those 2091 // statements. This block can also contain statements that precede the loop. 2092 if (Stmt *I = F->getInit()) { 2093 Block = createBlock(); 2094 return addStmt(I); 2095 } 2096 2097 // There is no loop initialization. We are thus basically a while loop. 2098 // NULL out Block to force lazy block construction. 2099 Block = NULL; 2100 Succ = EntryConditionBlock; 2101 return EntryConditionBlock; 2102} 2103 2104CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 2105 if (asc.alwaysAdd(*this, M)) { 2106 autoCreateBlock(); 2107 appendStmt(Block, M); 2108 } 2109 return Visit(M->getBase()); 2110} 2111 2112CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 2113 // Objective-C fast enumeration 'for' statements: 2114 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 2115 // 2116 // for ( Type newVariable in collection_expression ) { statements } 2117 // 2118 // becomes: 2119 // 2120 // prologue: 2121 // 1. collection_expression 2122 // T. jump to loop_entry 2123 // loop_entry: 2124 // 1. side-effects of element expression 2125 // 1. ObjCForCollectionStmt [performs binding to newVariable] 2126 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 2127 // TB: 2128 // statements 2129 // T. jump to loop_entry 2130 // FB: 2131 // what comes after 2132 // 2133 // and 2134 // 2135 // Type existingItem; 2136 // for ( existingItem in expression ) { statements } 2137 // 2138 // becomes: 2139 // 2140 // the same with newVariable replaced with existingItem; the binding works 2141 // the same except that for one ObjCForCollectionStmt::getElement() returns 2142 // a DeclStmt and the other returns a DeclRefExpr. 2143 // 2144 2145 CFGBlock *LoopSuccessor = 0; 2146 2147 if (Block) { 2148 if (badCFG) 2149 return 0; 2150 LoopSuccessor = Block; 2151 Block = 0; 2152 } else 2153 LoopSuccessor = Succ; 2154 2155 // Build the condition blocks. 2156 CFGBlock *ExitConditionBlock = createBlock(false); 2157 2158 // Set the terminator for the "exit" condition block. 2159 ExitConditionBlock->setTerminator(S); 2160 2161 // The last statement in the block should be the ObjCForCollectionStmt, which 2162 // performs the actual binding to 'element' and determines if there are any 2163 // more items in the collection. 2164 appendStmt(ExitConditionBlock, S); 2165 Block = ExitConditionBlock; 2166 2167 // Walk the 'element' expression to see if there are any side-effects. We 2168 // generate new blocks as necessary. We DON'T add the statement by default to 2169 // the CFG unless it contains control-flow. 2170 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 2171 AddStmtChoice::NotAlwaysAdd); 2172 if (Block) { 2173 if (badCFG) 2174 return 0; 2175 Block = 0; 2176 } 2177 2178 // The condition block is the implicit successor for the loop body as well as 2179 // any code above the loop. 2180 Succ = EntryConditionBlock; 2181 2182 // Now create the true branch. 2183 { 2184 // Save the current values for Succ, continue and break targets. 2185 SaveAndRestore<CFGBlock*> save_Succ(Succ); 2186 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2187 save_break(BreakJumpTarget); 2188 2189 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2190 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2191 2192 CFGBlock *BodyBlock = addStmt(S->getBody()); 2193 2194 if (!BodyBlock) 2195 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 2196 else if (Block) { 2197 if (badCFG) 2198 return 0; 2199 } 2200 2201 // This new body block is a successor to our "exit" condition block. 2202 addSuccessor(ExitConditionBlock, BodyBlock); 2203 } 2204 2205 // Link up the condition block with the code that follows the loop. 2206 // (the false branch). 2207 addSuccessor(ExitConditionBlock, LoopSuccessor); 2208 2209 // Now create a prologue block to contain the collection expression. 2210 Block = createBlock(); 2211 return addStmt(S->getCollection()); 2212} 2213 2214CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) { 2215 // Inline the body. 2216 return addStmt(S->getSubStmt()); 2217 // TODO: consider adding cleanups for the end of @autoreleasepool scope. 2218} 2219 2220CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 2221 // FIXME: Add locking 'primitives' to CFG for @synchronized. 2222 2223 // Inline the body. 2224 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 2225 2226 // The sync body starts its own basic block. This makes it a little easier 2227 // for diagnostic clients. 2228 if (SyncBlock) { 2229 if (badCFG) 2230 return 0; 2231 2232 Block = 0; 2233 Succ = SyncBlock; 2234 } 2235 2236 // Add the @synchronized to the CFG. 2237 autoCreateBlock(); 2238 appendStmt(Block, S); 2239 2240 // Inline the sync expression. 2241 return addStmt(S->getSynchExpr()); 2242} 2243 2244CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 2245 // FIXME 2246 return NYS(); 2247} 2248 2249CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) { 2250 autoCreateBlock(); 2251 2252 // Add the PseudoObject as the last thing. 2253 appendStmt(Block, E); 2254 2255 CFGBlock *lastBlock = Block; 2256 2257 // Before that, evaluate all of the semantics in order. In 2258 // CFG-land, that means appending them in reverse order. 2259 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) { 2260 Expr *Semantic = E->getSemanticExpr(--i); 2261 2262 // If the semantic is an opaque value, we're being asked to bind 2263 // it to its source expression. 2264 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic)) 2265 Semantic = OVE->getSourceExpr(); 2266 2267 if (CFGBlock *B = Visit(Semantic)) 2268 lastBlock = B; 2269 } 2270 2271 return lastBlock; 2272} 2273 2274CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 2275 CFGBlock *LoopSuccessor = NULL; 2276 2277 // Save local scope position because in case of condition variable ScopePos 2278 // won't be restored when traversing AST. 2279 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2280 2281 // Create local scope for possible condition variable. 2282 // Store scope position for continue statement. 2283 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 2284 if (VarDecl *VD = W->getConditionVariable()) { 2285 addLocalScopeForVarDecl(VD); 2286 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2287 } 2288 2289 // "while" is a control-flow statement. Thus we stop processing the current 2290 // block. 2291 if (Block) { 2292 if (badCFG) 2293 return 0; 2294 LoopSuccessor = Block; 2295 Block = 0; 2296 } else { 2297 LoopSuccessor = Succ; 2298 } 2299 2300 CFGBlock *BodyBlock = 0, *TransitionBlock = 0; 2301 2302 // Process the loop body. 2303 { 2304 assert(W->getBody()); 2305 2306 // Save the current values for Block, Succ, continue and break targets. 2307 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2308 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2309 save_break(BreakJumpTarget); 2310 2311 // Create an empty block to represent the transition block for looping back 2312 // to the head of the loop. 2313 Succ = TransitionBlock = createBlock(false); 2314 TransitionBlock->setLoopTarget(W); 2315 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 2316 2317 // All breaks should go to the code following the loop. 2318 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2319 2320 // Loop body should end with destructor of Condition variable (if any). 2321 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2322 2323 // If body is not a compound statement create implicit scope 2324 // and add destructors. 2325 if (!isa<CompoundStmt>(W->getBody())) 2326 addLocalScopeAndDtors(W->getBody()); 2327 2328 // Create the body. The returned block is the entry to the loop body. 2329 BodyBlock = addStmt(W->getBody()); 2330 2331 if (!BodyBlock) 2332 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2333 else if (Block && badCFG) 2334 return 0; 2335 } 2336 2337 // Because of short-circuit evaluation, the condition of the loop can span 2338 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2339 // evaluate the condition. 2340 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0; 2341 2342 do { 2343 Expr *C = W->getCond(); 2344 2345 // Specially handle logical operators, which have a slightly 2346 // more optimal CFG representation. 2347 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens())) 2348 if (Cond->isLogicalOp()) { 2349 llvm::tie(EntryConditionBlock, ExitConditionBlock) = 2350 VisitLogicalOperator(Cond, W, BodyBlock, 2351 LoopSuccessor); 2352 break; 2353 } 2354 2355 // The default case when not handling logical operators. 2356 ExitConditionBlock = createBlock(false); 2357 ExitConditionBlock->setTerminator(W); 2358 2359 // Now add the actual condition to the condition block. 2360 // Because the condition itself may contain control-flow, new blocks may 2361 // be created. Thus we update "Succ" after adding the condition. 2362 Block = ExitConditionBlock; 2363 Block = EntryConditionBlock = addStmt(C); 2364 2365 // If this block contains a condition variable, add both the condition 2366 // variable and initializer to the CFG. 2367 if (VarDecl *VD = W->getConditionVariable()) { 2368 if (Expr *Init = VD->getInit()) { 2369 autoCreateBlock(); 2370 appendStmt(Block, W->getConditionVariableDeclStmt()); 2371 EntryConditionBlock = addStmt(Init); 2372 assert(Block == EntryConditionBlock); 2373 } 2374 } 2375 2376 if (Block && badCFG) 2377 return 0; 2378 2379 // See if this is a known constant. 2380 const TryResult& KnownVal = tryEvaluateBool(C); 2381 2382 // Add the loop body entry as a successor to the condition. 2383 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2384 // Link up the condition block with the code that follows the loop. (the 2385 // false branch). 2386 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2387 2388 } while(false); 2389 2390 // Link up the loop-back block to the entry condition block. 2391 addSuccessor(TransitionBlock, EntryConditionBlock); 2392 2393 // There can be no more statements in the condition block since we loop back 2394 // to this block. NULL out Block to force lazy creation of another block. 2395 Block = NULL; 2396 2397 // Return the condition block, which is the dominating block for the loop. 2398 Succ = EntryConditionBlock; 2399 return EntryConditionBlock; 2400} 2401 2402 2403CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2404 // FIXME: For now we pretend that @catch and the code it contains does not 2405 // exit. 2406 return Block; 2407} 2408 2409CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2410 // FIXME: This isn't complete. We basically treat @throw like a return 2411 // statement. 2412 2413 // If we were in the middle of a block we stop processing that block. 2414 if (badCFG) 2415 return 0; 2416 2417 // Create the new block. 2418 Block = createBlock(false); 2419 2420 // The Exit block is the only successor. 2421 addSuccessor(Block, &cfg->getExit()); 2422 2423 // Add the statement to the block. This may create new blocks if S contains 2424 // control-flow (short-circuit operations). 2425 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2426} 2427 2428CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2429 // If we were in the middle of a block we stop processing that block. 2430 if (badCFG) 2431 return 0; 2432 2433 // Create the new block. 2434 Block = createBlock(false); 2435 2436 if (TryTerminatedBlock) 2437 // The current try statement is the only successor. 2438 addSuccessor(Block, TryTerminatedBlock); 2439 else 2440 // otherwise the Exit block is the only successor. 2441 addSuccessor(Block, &cfg->getExit()); 2442 2443 // Add the statement to the block. This may create new blocks if S contains 2444 // control-flow (short-circuit operations). 2445 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2446} 2447 2448CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2449 CFGBlock *LoopSuccessor = NULL; 2450 2451 // "do...while" is a control-flow statement. Thus we stop processing the 2452 // current block. 2453 if (Block) { 2454 if (badCFG) 2455 return 0; 2456 LoopSuccessor = Block; 2457 } else 2458 LoopSuccessor = Succ; 2459 2460 // Because of short-circuit evaluation, the condition of the loop can span 2461 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2462 // evaluate the condition. 2463 CFGBlock *ExitConditionBlock = createBlock(false); 2464 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2465 2466 // Set the terminator for the "exit" condition block. 2467 ExitConditionBlock->setTerminator(D); 2468 2469 // Now add the actual condition to the condition block. Because the condition 2470 // itself may contain control-flow, new blocks may be created. 2471 if (Stmt *C = D->getCond()) { 2472 Block = ExitConditionBlock; 2473 EntryConditionBlock = addStmt(C); 2474 if (Block) { 2475 if (badCFG) 2476 return 0; 2477 } 2478 } 2479 2480 // The condition block is the implicit successor for the loop body. 2481 Succ = EntryConditionBlock; 2482 2483 // See if this is a known constant. 2484 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2485 2486 // Process the loop body. 2487 CFGBlock *BodyBlock = NULL; 2488 { 2489 assert(D->getBody()); 2490 2491 // Save the current values for Block, Succ, and continue and break targets 2492 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2493 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2494 save_break(BreakJumpTarget); 2495 2496 // All continues within this loop should go to the condition block 2497 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2498 2499 // All breaks should go to the code following the loop. 2500 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2501 2502 // NULL out Block to force lazy instantiation of blocks for the body. 2503 Block = NULL; 2504 2505 // If body is not a compound statement create implicit scope 2506 // and add destructors. 2507 if (!isa<CompoundStmt>(D->getBody())) 2508 addLocalScopeAndDtors(D->getBody()); 2509 2510 // Create the body. The returned block is the entry to the loop body. 2511 BodyBlock = addStmt(D->getBody()); 2512 2513 if (!BodyBlock) 2514 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2515 else if (Block) { 2516 if (badCFG) 2517 return 0; 2518 } 2519 2520 if (!KnownVal.isFalse()) { 2521 // Add an intermediate block between the BodyBlock and the 2522 // ExitConditionBlock to represent the "loop back" transition. Create an 2523 // empty block to represent the transition block for looping back to the 2524 // head of the loop. 2525 // FIXME: Can we do this more efficiently without adding another block? 2526 Block = NULL; 2527 Succ = BodyBlock; 2528 CFGBlock *LoopBackBlock = createBlock(); 2529 LoopBackBlock->setLoopTarget(D); 2530 2531 // Add the loop body entry as a successor to the condition. 2532 addSuccessor(ExitConditionBlock, LoopBackBlock); 2533 } 2534 else 2535 addSuccessor(ExitConditionBlock, NULL); 2536 } 2537 2538 // Link up the condition block with the code that follows the loop. 2539 // (the false branch). 2540 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2541 2542 // There can be no more statements in the body block(s) since we loop back to 2543 // the body. NULL out Block to force lazy creation of another block. 2544 Block = NULL; 2545 2546 // Return the loop body, which is the dominating block for the loop. 2547 Succ = BodyBlock; 2548 return BodyBlock; 2549} 2550 2551CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2552 // "continue" is a control-flow statement. Thus we stop processing the 2553 // current block. 2554 if (badCFG) 2555 return 0; 2556 2557 // Now create a new block that ends with the continue statement. 2558 Block = createBlock(false); 2559 Block->setTerminator(C); 2560 2561 // If there is no target for the continue, then we are looking at an 2562 // incomplete AST. This means the CFG cannot be constructed. 2563 if (ContinueJumpTarget.block) { 2564 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2565 addSuccessor(Block, ContinueJumpTarget.block); 2566 } else 2567 badCFG = true; 2568 2569 return Block; 2570} 2571 2572CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2573 AddStmtChoice asc) { 2574 2575 if (asc.alwaysAdd(*this, E)) { 2576 autoCreateBlock(); 2577 appendStmt(Block, E); 2578 } 2579 2580 // VLA types have expressions that must be evaluated. 2581 CFGBlock *lastBlock = Block; 2582 2583 if (E->isArgumentType()) { 2584 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2585 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2586 lastBlock = addStmt(VA->getSizeExpr()); 2587 } 2588 return lastBlock; 2589} 2590 2591/// VisitStmtExpr - Utility method to handle (nested) statement 2592/// expressions (a GCC extension). 2593CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2594 if (asc.alwaysAdd(*this, SE)) { 2595 autoCreateBlock(); 2596 appendStmt(Block, SE); 2597 } 2598 return VisitCompoundStmt(SE->getSubStmt()); 2599} 2600 2601CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2602 // "switch" is a control-flow statement. Thus we stop processing the current 2603 // block. 2604 CFGBlock *SwitchSuccessor = NULL; 2605 2606 // Save local scope position because in case of condition variable ScopePos 2607 // won't be restored when traversing AST. 2608 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2609 2610 // Create local scope for possible condition variable. 2611 // Store scope position. Add implicit destructor. 2612 if (VarDecl *VD = Terminator->getConditionVariable()) { 2613 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2614 addLocalScopeForVarDecl(VD); 2615 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2616 } 2617 2618 if (Block) { 2619 if (badCFG) 2620 return 0; 2621 SwitchSuccessor = Block; 2622 } else SwitchSuccessor = Succ; 2623 2624 // Save the current "switch" context. 2625 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2626 save_default(DefaultCaseBlock); 2627 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2628 2629 // Set the "default" case to be the block after the switch statement. If the 2630 // switch statement contains a "default:", this value will be overwritten with 2631 // the block for that code. 2632 DefaultCaseBlock = SwitchSuccessor; 2633 2634 // Create a new block that will contain the switch statement. 2635 SwitchTerminatedBlock = createBlock(false); 2636 2637 // Now process the switch body. The code after the switch is the implicit 2638 // successor. 2639 Succ = SwitchSuccessor; 2640 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2641 2642 // When visiting the body, the case statements should automatically get linked 2643 // up to the switch. We also don't keep a pointer to the body, since all 2644 // control-flow from the switch goes to case/default statements. 2645 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2646 Block = NULL; 2647 2648 // For pruning unreachable case statements, save the current state 2649 // for tracking the condition value. 2650 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2651 false); 2652 2653 // Determine if the switch condition can be explicitly evaluated. 2654 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2655 Expr::EvalResult result; 2656 bool b = tryEvaluate(Terminator->getCond(), result); 2657 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2658 b ? &result : 0); 2659 2660 // If body is not a compound statement create implicit scope 2661 // and add destructors. 2662 if (!isa<CompoundStmt>(Terminator->getBody())) 2663 addLocalScopeAndDtors(Terminator->getBody()); 2664 2665 addStmt(Terminator->getBody()); 2666 if (Block) { 2667 if (badCFG) 2668 return 0; 2669 } 2670 2671 // If we have no "default:" case, the default transition is to the code 2672 // following the switch body. Moreover, take into account if all the 2673 // cases of a switch are covered (e.g., switching on an enum value). 2674 addSuccessor(SwitchTerminatedBlock, 2675 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2676 ? 0 : DefaultCaseBlock); 2677 2678 // Add the terminator and condition in the switch block. 2679 SwitchTerminatedBlock->setTerminator(Terminator); 2680 Block = SwitchTerminatedBlock; 2681 CFGBlock *LastBlock = addStmt(Terminator->getCond()); 2682 2683 // Finally, if the SwitchStmt contains a condition variable, add both the 2684 // SwitchStmt and the condition variable initialization to the CFG. 2685 if (VarDecl *VD = Terminator->getConditionVariable()) { 2686 if (Expr *Init = VD->getInit()) { 2687 autoCreateBlock(); 2688 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2689 LastBlock = addStmt(Init); 2690 } 2691 } 2692 2693 return LastBlock; 2694} 2695 2696static bool shouldAddCase(bool &switchExclusivelyCovered, 2697 const Expr::EvalResult *switchCond, 2698 const CaseStmt *CS, 2699 ASTContext &Ctx) { 2700 if (!switchCond) 2701 return true; 2702 2703 bool addCase = false; 2704 2705 if (!switchExclusivelyCovered) { 2706 if (switchCond->Val.isInt()) { 2707 // Evaluate the LHS of the case value. 2708 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2709 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2710 2711 if (condInt == lhsInt) { 2712 addCase = true; 2713 switchExclusivelyCovered = true; 2714 } 2715 else if (condInt < lhsInt) { 2716 if (const Expr *RHS = CS->getRHS()) { 2717 // Evaluate the RHS of the case value. 2718 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2719 if (V2 <= condInt) { 2720 addCase = true; 2721 switchExclusivelyCovered = true; 2722 } 2723 } 2724 } 2725 } 2726 else 2727 addCase = true; 2728 } 2729 return addCase; 2730} 2731 2732CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2733 // CaseStmts are essentially labels, so they are the first statement in a 2734 // block. 2735 CFGBlock *TopBlock = 0, *LastBlock = 0; 2736 2737 if (Stmt *Sub = CS->getSubStmt()) { 2738 // For deeply nested chains of CaseStmts, instead of doing a recursion 2739 // (which can blow out the stack), manually unroll and create blocks 2740 // along the way. 2741 while (isa<CaseStmt>(Sub)) { 2742 CFGBlock *currentBlock = createBlock(false); 2743 currentBlock->setLabel(CS); 2744 2745 if (TopBlock) 2746 addSuccessor(LastBlock, currentBlock); 2747 else 2748 TopBlock = currentBlock; 2749 2750 addSuccessor(SwitchTerminatedBlock, 2751 shouldAddCase(switchExclusivelyCovered, switchCond, 2752 CS, *Context) 2753 ? currentBlock : 0); 2754 2755 LastBlock = currentBlock; 2756 CS = cast<CaseStmt>(Sub); 2757 Sub = CS->getSubStmt(); 2758 } 2759 2760 addStmt(Sub); 2761 } 2762 2763 CFGBlock *CaseBlock = Block; 2764 if (!CaseBlock) 2765 CaseBlock = createBlock(); 2766 2767 // Cases statements partition blocks, so this is the top of the basic block we 2768 // were processing (the "case XXX:" is the label). 2769 CaseBlock->setLabel(CS); 2770 2771 if (badCFG) 2772 return 0; 2773 2774 // Add this block to the list of successors for the block with the switch 2775 // statement. 2776 assert(SwitchTerminatedBlock); 2777 addSuccessor(SwitchTerminatedBlock, 2778 shouldAddCase(switchExclusivelyCovered, switchCond, 2779 CS, *Context) 2780 ? CaseBlock : 0); 2781 2782 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2783 Block = NULL; 2784 2785 if (TopBlock) { 2786 addSuccessor(LastBlock, CaseBlock); 2787 Succ = TopBlock; 2788 } else { 2789 // This block is now the implicit successor of other blocks. 2790 Succ = CaseBlock; 2791 } 2792 2793 return Succ; 2794} 2795 2796CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2797 if (Terminator->getSubStmt()) 2798 addStmt(Terminator->getSubStmt()); 2799 2800 DefaultCaseBlock = Block; 2801 2802 if (!DefaultCaseBlock) 2803 DefaultCaseBlock = createBlock(); 2804 2805 // Default statements partition blocks, so this is the top of the basic block 2806 // we were processing (the "default:" is the label). 2807 DefaultCaseBlock->setLabel(Terminator); 2808 2809 if (badCFG) 2810 return 0; 2811 2812 // Unlike case statements, we don't add the default block to the successors 2813 // for the switch statement immediately. This is done when we finish 2814 // processing the switch statement. This allows for the default case 2815 // (including a fall-through to the code after the switch statement) to always 2816 // be the last successor of a switch-terminated block. 2817 2818 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2819 Block = NULL; 2820 2821 // This block is now the implicit successor of other blocks. 2822 Succ = DefaultCaseBlock; 2823 2824 return DefaultCaseBlock; 2825} 2826 2827CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2828 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2829 // current block. 2830 CFGBlock *TrySuccessor = NULL; 2831 2832 if (Block) { 2833 if (badCFG) 2834 return 0; 2835 TrySuccessor = Block; 2836 } else TrySuccessor = Succ; 2837 2838 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2839 2840 // Create a new block that will contain the try statement. 2841 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2842 // Add the terminator in the try block. 2843 NewTryTerminatedBlock->setTerminator(Terminator); 2844 2845 bool HasCatchAll = false; 2846 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2847 // The code after the try is the implicit successor. 2848 Succ = TrySuccessor; 2849 CXXCatchStmt *CS = Terminator->getHandler(h); 2850 if (CS->getExceptionDecl() == 0) { 2851 HasCatchAll = true; 2852 } 2853 Block = NULL; 2854 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2855 if (CatchBlock == 0) 2856 return 0; 2857 // Add this block to the list of successors for the block with the try 2858 // statement. 2859 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2860 } 2861 if (!HasCatchAll) { 2862 if (PrevTryTerminatedBlock) 2863 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2864 else 2865 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2866 } 2867 2868 // The code after the try is the implicit successor. 2869 Succ = TrySuccessor; 2870 2871 // Save the current "try" context. 2872 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2873 cfg->addTryDispatchBlock(TryTerminatedBlock); 2874 2875 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2876 Block = NULL; 2877 return addStmt(Terminator->getTryBlock()); 2878} 2879 2880CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2881 // CXXCatchStmt are treated like labels, so they are the first statement in a 2882 // block. 2883 2884 // Save local scope position because in case of exception variable ScopePos 2885 // won't be restored when traversing AST. 2886 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2887 2888 // Create local scope for possible exception variable. 2889 // Store scope position. Add implicit destructor. 2890 if (VarDecl *VD = CS->getExceptionDecl()) { 2891 LocalScope::const_iterator BeginScopePos = ScopePos; 2892 addLocalScopeForVarDecl(VD); 2893 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2894 } 2895 2896 if (CS->getHandlerBlock()) 2897 addStmt(CS->getHandlerBlock()); 2898 2899 CFGBlock *CatchBlock = Block; 2900 if (!CatchBlock) 2901 CatchBlock = createBlock(); 2902 2903 // CXXCatchStmt is more than just a label. They have semantic meaning 2904 // as well, as they implicitly "initialize" the catch variable. Add 2905 // it to the CFG as a CFGElement so that the control-flow of these 2906 // semantics gets captured. 2907 appendStmt(CatchBlock, CS); 2908 2909 // Also add the CXXCatchStmt as a label, to mirror handling of regular 2910 // labels. 2911 CatchBlock->setLabel(CS); 2912 2913 // Bail out if the CFG is bad. 2914 if (badCFG) 2915 return 0; 2916 2917 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2918 Block = NULL; 2919 2920 return CatchBlock; 2921} 2922 2923CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2924 // C++0x for-range statements are specified as [stmt.ranged]: 2925 // 2926 // { 2927 // auto && __range = range-init; 2928 // for ( auto __begin = begin-expr, 2929 // __end = end-expr; 2930 // __begin != __end; 2931 // ++__begin ) { 2932 // for-range-declaration = *__begin; 2933 // statement 2934 // } 2935 // } 2936 2937 // Save local scope position before the addition of the implicit variables. 2938 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2939 2940 // Create local scopes and destructors for range, begin and end variables. 2941 if (Stmt *Range = S->getRangeStmt()) 2942 addLocalScopeForStmt(Range); 2943 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2944 addLocalScopeForStmt(BeginEnd); 2945 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2946 2947 LocalScope::const_iterator ContinueScopePos = ScopePos; 2948 2949 // "for" is a control-flow statement. Thus we stop processing the current 2950 // block. 2951 CFGBlock *LoopSuccessor = NULL; 2952 if (Block) { 2953 if (badCFG) 2954 return 0; 2955 LoopSuccessor = Block; 2956 } else 2957 LoopSuccessor = Succ; 2958 2959 // Save the current value for the break targets. 2960 // All breaks should go to the code following the loop. 2961 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2962 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2963 2964 // The block for the __begin != __end expression. 2965 CFGBlock *ConditionBlock = createBlock(false); 2966 ConditionBlock->setTerminator(S); 2967 2968 // Now add the actual condition to the condition block. 2969 if (Expr *C = S->getCond()) { 2970 Block = ConditionBlock; 2971 CFGBlock *BeginConditionBlock = addStmt(C); 2972 if (badCFG) 2973 return 0; 2974 assert(BeginConditionBlock == ConditionBlock && 2975 "condition block in for-range was unexpectedly complex"); 2976 (void)BeginConditionBlock; 2977 } 2978 2979 // The condition block is the implicit successor for the loop body as well as 2980 // any code above the loop. 2981 Succ = ConditionBlock; 2982 2983 // See if this is a known constant. 2984 TryResult KnownVal(true); 2985 2986 if (S->getCond()) 2987 KnownVal = tryEvaluateBool(S->getCond()); 2988 2989 // Now create the loop body. 2990 { 2991 assert(S->getBody()); 2992 2993 // Save the current values for Block, Succ, and continue targets. 2994 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2995 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2996 2997 // Generate increment code in its own basic block. This is the target of 2998 // continue statements. 2999 Block = 0; 3000 Succ = addStmt(S->getInc()); 3001 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 3002 3003 // The starting block for the loop increment is the block that should 3004 // represent the 'loop target' for looping back to the start of the loop. 3005 ContinueJumpTarget.block->setLoopTarget(S); 3006 3007 // Finish up the increment block and prepare to start the loop body. 3008 assert(Block); 3009 if (badCFG) 3010 return 0; 3011 Block = 0; 3012 3013 3014 // Add implicit scope and dtors for loop variable. 3015 addLocalScopeAndDtors(S->getLoopVarStmt()); 3016 3017 // Populate a new block to contain the loop body and loop variable. 3018 addStmt(S->getBody()); 3019 if (badCFG) 3020 return 0; 3021 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt()); 3022 if (badCFG) 3023 return 0; 3024 3025 // This new body block is a successor to our condition block. 3026 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : LoopVarStmtBlock); 3027 } 3028 3029 // Link up the condition block with the code that follows the loop (the 3030 // false branch). 3031 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 3032 3033 // Add the initialization statements. 3034 Block = createBlock(); 3035 addStmt(S->getBeginEndStmt()); 3036 return addStmt(S->getRangeStmt()); 3037} 3038 3039CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 3040 AddStmtChoice asc) { 3041 if (BuildOpts.AddTemporaryDtors) { 3042 // If adding implicit destructors visit the full expression for adding 3043 // destructors of temporaries. 3044 VisitForTemporaryDtors(E->getSubExpr()); 3045 3046 // Full expression has to be added as CFGStmt so it will be sequenced 3047 // before destructors of it's temporaries. 3048 asc = asc.withAlwaysAdd(true); 3049 } 3050 return Visit(E->getSubExpr(), asc); 3051} 3052 3053CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 3054 AddStmtChoice asc) { 3055 if (asc.alwaysAdd(*this, E)) { 3056 autoCreateBlock(); 3057 appendStmt(Block, E); 3058 3059 // We do not want to propagate the AlwaysAdd property. 3060 asc = asc.withAlwaysAdd(false); 3061 } 3062 return Visit(E->getSubExpr(), asc); 3063} 3064 3065CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 3066 AddStmtChoice asc) { 3067 autoCreateBlock(); 3068 appendStmt(Block, C); 3069 3070 return VisitChildren(C); 3071} 3072 3073CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 3074 AddStmtChoice asc) { 3075 if (asc.alwaysAdd(*this, E)) { 3076 autoCreateBlock(); 3077 appendStmt(Block, E); 3078 // We do not want to propagate the AlwaysAdd property. 3079 asc = asc.withAlwaysAdd(false); 3080 } 3081 return Visit(E->getSubExpr(), asc); 3082} 3083 3084CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 3085 AddStmtChoice asc) { 3086 autoCreateBlock(); 3087 appendStmt(Block, C); 3088 return VisitChildren(C); 3089} 3090 3091CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 3092 AddStmtChoice asc) { 3093 if (asc.alwaysAdd(*this, E)) { 3094 autoCreateBlock(); 3095 appendStmt(Block, E); 3096 } 3097 return Visit(E->getSubExpr(), AddStmtChoice()); 3098} 3099 3100CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3101 // Lazily create the indirect-goto dispatch block if there isn't one already. 3102 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 3103 3104 if (!IBlock) { 3105 IBlock = createBlock(false); 3106 cfg->setIndirectGotoBlock(IBlock); 3107 } 3108 3109 // IndirectGoto is a control-flow statement. Thus we stop processing the 3110 // current block and create a new one. 3111 if (badCFG) 3112 return 0; 3113 3114 Block = createBlock(false); 3115 Block->setTerminator(I); 3116 addSuccessor(Block, IBlock); 3117 return addStmt(I->getTarget()); 3118} 3119 3120CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 3121 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors); 3122 3123tryAgain: 3124 if (!E) { 3125 badCFG = true; 3126 return NULL; 3127 } 3128 switch (E->getStmtClass()) { 3129 default: 3130 return VisitChildrenForTemporaryDtors(E); 3131 3132 case Stmt::BinaryOperatorClass: 3133 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 3134 3135 case Stmt::CXXBindTemporaryExprClass: 3136 return VisitCXXBindTemporaryExprForTemporaryDtors( 3137 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 3138 3139 case Stmt::BinaryConditionalOperatorClass: 3140 case Stmt::ConditionalOperatorClass: 3141 return VisitConditionalOperatorForTemporaryDtors( 3142 cast<AbstractConditionalOperator>(E), BindToTemporary); 3143 3144 case Stmt::ImplicitCastExprClass: 3145 // For implicit cast we want BindToTemporary to be passed further. 3146 E = cast<CastExpr>(E)->getSubExpr(); 3147 goto tryAgain; 3148 3149 case Stmt::ParenExprClass: 3150 E = cast<ParenExpr>(E)->getSubExpr(); 3151 goto tryAgain; 3152 3153 case Stmt::MaterializeTemporaryExprClass: 3154 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 3155 goto tryAgain; 3156 } 3157} 3158 3159CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 3160 // When visiting children for destructors we want to visit them in reverse 3161 // order that they will appear in the CFG. Because the CFG is built 3162 // bottom-up, this means we visit them in their natural order, which 3163 // reverses them in the CFG. 3164 CFGBlock *B = Block; 3165 for (Stmt::child_range I = E->children(); I; ++I) { 3166 if (Stmt *Child = *I) 3167 if (CFGBlock *R = VisitForTemporaryDtors(Child)) 3168 B = R; 3169 } 3170 return B; 3171} 3172 3173CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 3174 if (E->isLogicalOp()) { 3175 // Destructors for temporaries in LHS expression should be called after 3176 // those for RHS expression. Even if this will unnecessarily create a block, 3177 // this block will be used at least by the full expression. 3178 autoCreateBlock(); 3179 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 3180 if (badCFG) 3181 return NULL; 3182 3183 Succ = ConfluenceBlock; 3184 Block = NULL; 3185 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3186 3187 if (RHSBlock) { 3188 if (badCFG) 3189 return NULL; 3190 3191 // If RHS expression did produce destructors we need to connect created 3192 // blocks to CFG in same manner as for binary operator itself. 3193 CFGBlock *LHSBlock = createBlock(false); 3194 LHSBlock->setTerminator(CFGTerminator(E, true)); 3195 3196 // For binary operator LHS block is before RHS in list of predecessors 3197 // of ConfluenceBlock. 3198 std::reverse(ConfluenceBlock->pred_begin(), 3199 ConfluenceBlock->pred_end()); 3200 3201 // See if this is a known constant. 3202 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 3203 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 3204 KnownVal.negate(); 3205 3206 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 3207 // itself. 3208 if (E->getOpcode() == BO_LOr) { 3209 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3210 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3211 } else { 3212 assert (E->getOpcode() == BO_LAnd); 3213 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3214 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3215 } 3216 3217 Block = LHSBlock; 3218 return LHSBlock; 3219 } 3220 3221 Block = ConfluenceBlock; 3222 return ConfluenceBlock; 3223 } 3224 3225 if (E->isAssignmentOp()) { 3226 // For assignment operator (=) LHS expression is visited 3227 // before RHS expression. For destructors visit them in reverse order. 3228 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3229 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3230 return LHSBlock ? LHSBlock : RHSBlock; 3231 } 3232 3233 // For any other binary operator RHS expression is visited before 3234 // LHS expression (order of children). For destructors visit them in reverse 3235 // order. 3236 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3237 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3238 return RHSBlock ? RHSBlock : LHSBlock; 3239} 3240 3241CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 3242 CXXBindTemporaryExpr *E, bool BindToTemporary) { 3243 // First add destructors for temporaries in subexpression. 3244 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 3245 if (!BindToTemporary) { 3246 // If lifetime of temporary is not prolonged (by assigning to constant 3247 // reference) add destructor for it. 3248 3249 // If the destructor is marked as a no-return destructor, we need to create 3250 // a new block for the destructor which does not have as a successor 3251 // anything built thus far. Control won't flow out of this block. 3252 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 3253 if (Dtor->isNoReturn()) 3254 Block = createNoReturnBlock(); 3255 else 3256 autoCreateBlock(); 3257 3258 appendTemporaryDtor(Block, E); 3259 B = Block; 3260 } 3261 return B; 3262} 3263 3264CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 3265 AbstractConditionalOperator *E, bool BindToTemporary) { 3266 // First add destructors for condition expression. Even if this will 3267 // unnecessarily create a block, this block will be used at least by the full 3268 // expression. 3269 autoCreateBlock(); 3270 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 3271 if (badCFG) 3272 return NULL; 3273 if (BinaryConditionalOperator *BCO 3274 = dyn_cast<BinaryConditionalOperator>(E)) { 3275 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 3276 if (badCFG) 3277 return NULL; 3278 } 3279 3280 // Try to add block with destructors for LHS expression. 3281 CFGBlock *LHSBlock = NULL; 3282 Succ = ConfluenceBlock; 3283 Block = NULL; 3284 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 3285 if (badCFG) 3286 return NULL; 3287 3288 // Try to add block with destructors for RHS expression; 3289 Succ = ConfluenceBlock; 3290 Block = NULL; 3291 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 3292 BindToTemporary); 3293 if (badCFG) 3294 return NULL; 3295 3296 if (!RHSBlock && !LHSBlock) { 3297 // If neither LHS nor RHS expression had temporaries to destroy don't create 3298 // more blocks. 3299 Block = ConfluenceBlock; 3300 return Block; 3301 } 3302 3303 Block = createBlock(false); 3304 Block->setTerminator(CFGTerminator(E, true)); 3305 3306 // See if this is a known constant. 3307 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 3308 3309 if (LHSBlock) { 3310 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 3311 } else if (KnownVal.isFalse()) { 3312 addSuccessor(Block, NULL); 3313 } else { 3314 addSuccessor(Block, ConfluenceBlock); 3315 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 3316 } 3317 3318 if (!RHSBlock) 3319 RHSBlock = ConfluenceBlock; 3320 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 3321 3322 return Block; 3323} 3324 3325} // end anonymous namespace 3326 3327/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 3328/// no successors or predecessors. If this is the first block created in the 3329/// CFG, it is automatically set to be the Entry and Exit of the CFG. 3330CFGBlock *CFG::createBlock() { 3331 bool first_block = begin() == end(); 3332 3333 // Create the block. 3334 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 3335 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this); 3336 Blocks.push_back(Mem, BlkBVC); 3337 3338 // If this is the first block, set it as the Entry and Exit. 3339 if (first_block) 3340 Entry = Exit = &back(); 3341 3342 // Return the block. 3343 return &back(); 3344} 3345 3346/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 3347/// CFG is returned to the caller. 3348CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 3349 const BuildOptions &BO) { 3350 CFGBuilder Builder(C, BO); 3351 return Builder.buildCFG(D, Statement); 3352} 3353 3354const CXXDestructorDecl * 3355CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 3356 switch (getKind()) { 3357 case CFGElement::Statement: 3358 case CFGElement::Initializer: 3359 llvm_unreachable("getDestructorDecl should only be used with " 3360 "ImplicitDtors"); 3361 case CFGElement::AutomaticObjectDtor: { 3362 const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl(); 3363 QualType ty = var->getType(); 3364 ty = ty.getNonReferenceType(); 3365 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3366 ty = arrayType->getElementType(); 3367 } 3368 const RecordType *recordType = ty->getAs<RecordType>(); 3369 const CXXRecordDecl *classDecl = 3370 cast<CXXRecordDecl>(recordType->getDecl()); 3371 return classDecl->getDestructor(); 3372 } 3373 case CFGElement::TemporaryDtor: { 3374 const CXXBindTemporaryExpr *bindExpr = 3375 castAs<CFGTemporaryDtor>().getBindTemporaryExpr(); 3376 const CXXTemporary *temp = bindExpr->getTemporary(); 3377 return temp->getDestructor(); 3378 } 3379 case CFGElement::BaseDtor: 3380 case CFGElement::MemberDtor: 3381 3382 // Not yet supported. 3383 return 0; 3384 } 3385 llvm_unreachable("getKind() returned bogus value"); 3386} 3387 3388bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3389 if (const CXXDestructorDecl *DD = getDestructorDecl(astContext)) 3390 return DD->isNoReturn(); 3391 return false; 3392} 3393 3394//===----------------------------------------------------------------------===// 3395// Filtered walking of the CFG. 3396//===----------------------------------------------------------------------===// 3397 3398bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3399 const CFGBlock *From, const CFGBlock *To) { 3400 3401 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3402 // If the 'To' has no label or is labeled but the label isn't a 3403 // CaseStmt then filter this edge. 3404 if (const SwitchStmt *S = 3405 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3406 if (S->isAllEnumCasesCovered()) { 3407 const Stmt *L = To->getLabel(); 3408 if (!L || !isa<CaseStmt>(L)) 3409 return true; 3410 } 3411 } 3412 } 3413 3414 return false; 3415} 3416 3417//===----------------------------------------------------------------------===// 3418// CFG pretty printing 3419//===----------------------------------------------------------------------===// 3420 3421namespace { 3422 3423class StmtPrinterHelper : public PrinterHelper { 3424 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3425 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3426 StmtMapTy StmtMap; 3427 DeclMapTy DeclMap; 3428 signed currentBlock; 3429 unsigned currStmt; 3430 const LangOptions &LangOpts; 3431public: 3432 3433 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3434 : currentBlock(0), currStmt(0), LangOpts(LO) 3435 { 3436 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3437 unsigned j = 1; 3438 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3439 BI != BEnd; ++BI, ++j ) { 3440 if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) { 3441 const Stmt *stmt= SE->getStmt(); 3442 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3443 StmtMap[stmt] = P; 3444 3445 switch (stmt->getStmtClass()) { 3446 case Stmt::DeclStmtClass: 3447 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3448 break; 3449 case Stmt::IfStmtClass: { 3450 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3451 if (var) 3452 DeclMap[var] = P; 3453 break; 3454 } 3455 case Stmt::ForStmtClass: { 3456 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3457 if (var) 3458 DeclMap[var] = P; 3459 break; 3460 } 3461 case Stmt::WhileStmtClass: { 3462 const VarDecl *var = 3463 cast<WhileStmt>(stmt)->getConditionVariable(); 3464 if (var) 3465 DeclMap[var] = P; 3466 break; 3467 } 3468 case Stmt::SwitchStmtClass: { 3469 const VarDecl *var = 3470 cast<SwitchStmt>(stmt)->getConditionVariable(); 3471 if (var) 3472 DeclMap[var] = P; 3473 break; 3474 } 3475 case Stmt::CXXCatchStmtClass: { 3476 const VarDecl *var = 3477 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3478 if (var) 3479 DeclMap[var] = P; 3480 break; 3481 } 3482 default: 3483 break; 3484 } 3485 } 3486 } 3487 } 3488 } 3489 3490 3491 virtual ~StmtPrinterHelper() {} 3492 3493 const LangOptions &getLangOpts() const { return LangOpts; } 3494 void setBlockID(signed i) { currentBlock = i; } 3495 void setStmtID(unsigned i) { currStmt = i; } 3496 3497 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3498 StmtMapTy::iterator I = StmtMap.find(S); 3499 3500 if (I == StmtMap.end()) 3501 return false; 3502 3503 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3504 && I->second.second == currStmt) { 3505 return false; 3506 } 3507 3508 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3509 return true; 3510 } 3511 3512 bool handleDecl(const Decl *D, raw_ostream &OS) { 3513 DeclMapTy::iterator I = DeclMap.find(D); 3514 3515 if (I == DeclMap.end()) 3516 return false; 3517 3518 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3519 && I->second.second == currStmt) { 3520 return false; 3521 } 3522 3523 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3524 return true; 3525 } 3526}; 3527} // end anonymous namespace 3528 3529 3530namespace { 3531class CFGBlockTerminatorPrint 3532 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3533 3534 raw_ostream &OS; 3535 StmtPrinterHelper* Helper; 3536 PrintingPolicy Policy; 3537public: 3538 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3539 const PrintingPolicy &Policy) 3540 : OS(os), Helper(helper), Policy(Policy) {} 3541 3542 void VisitIfStmt(IfStmt *I) { 3543 OS << "if "; 3544 I->getCond()->printPretty(OS,Helper,Policy); 3545 } 3546 3547 // Default case. 3548 void VisitStmt(Stmt *Terminator) { 3549 Terminator->printPretty(OS, Helper, Policy); 3550 } 3551 3552 void VisitDeclStmt(DeclStmt *DS) { 3553 VarDecl *VD = cast<VarDecl>(DS->getSingleDecl()); 3554 OS << "static init " << VD->getName(); 3555 } 3556 3557 void VisitForStmt(ForStmt *F) { 3558 OS << "for (" ; 3559 if (F->getInit()) 3560 OS << "..."; 3561 OS << "; "; 3562 if (Stmt *C = F->getCond()) 3563 C->printPretty(OS, Helper, Policy); 3564 OS << "; "; 3565 if (F->getInc()) 3566 OS << "..."; 3567 OS << ")"; 3568 } 3569 3570 void VisitWhileStmt(WhileStmt *W) { 3571 OS << "while " ; 3572 if (Stmt *C = W->getCond()) 3573 C->printPretty(OS, Helper, Policy); 3574 } 3575 3576 void VisitDoStmt(DoStmt *D) { 3577 OS << "do ... while "; 3578 if (Stmt *C = D->getCond()) 3579 C->printPretty(OS, Helper, Policy); 3580 } 3581 3582 void VisitSwitchStmt(SwitchStmt *Terminator) { 3583 OS << "switch "; 3584 Terminator->getCond()->printPretty(OS, Helper, Policy); 3585 } 3586 3587 void VisitCXXTryStmt(CXXTryStmt *CS) { 3588 OS << "try ..."; 3589 } 3590 3591 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3592 C->getCond()->printPretty(OS, Helper, Policy); 3593 OS << " ? ... : ..."; 3594 } 3595 3596 void VisitChooseExpr(ChooseExpr *C) { 3597 OS << "__builtin_choose_expr( "; 3598 C->getCond()->printPretty(OS, Helper, Policy); 3599 OS << " )"; 3600 } 3601 3602 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3603 OS << "goto *"; 3604 I->getTarget()->printPretty(OS, Helper, Policy); 3605 } 3606 3607 void VisitBinaryOperator(BinaryOperator* B) { 3608 if (!B->isLogicalOp()) { 3609 VisitExpr(B); 3610 return; 3611 } 3612 3613 B->getLHS()->printPretty(OS, Helper, Policy); 3614 3615 switch (B->getOpcode()) { 3616 case BO_LOr: 3617 OS << " || ..."; 3618 return; 3619 case BO_LAnd: 3620 OS << " && ..."; 3621 return; 3622 default: 3623 llvm_unreachable("Invalid logical operator."); 3624 } 3625 } 3626 3627 void VisitExpr(Expr *E) { 3628 E->printPretty(OS, Helper, Policy); 3629 } 3630}; 3631} // end anonymous namespace 3632 3633static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3634 const CFGElement &E) { 3635 if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) { 3636 const Stmt *S = CS->getStmt(); 3637 3638 if (Helper) { 3639 3640 // special printing for statement-expressions. 3641 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3642 const CompoundStmt *Sub = SE->getSubStmt(); 3643 3644 if (Sub->children()) { 3645 OS << "({ ... ; "; 3646 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3647 OS << " })\n"; 3648 return; 3649 } 3650 } 3651 // special printing for comma expressions. 3652 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3653 if (B->getOpcode() == BO_Comma) { 3654 OS << "... , "; 3655 Helper->handledStmt(B->getRHS(),OS); 3656 OS << '\n'; 3657 return; 3658 } 3659 } 3660 } 3661 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3662 3663 if (isa<CXXOperatorCallExpr>(S)) { 3664 OS << " (OperatorCall)"; 3665 } 3666 else if (isa<CXXBindTemporaryExpr>(S)) { 3667 OS << " (BindTemporary)"; 3668 } 3669 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) { 3670 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")"; 3671 } 3672 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) { 3673 OS << " (" << CE->getStmtClassName() << ", " 3674 << CE->getCastKindName() 3675 << ", " << CE->getType().getAsString() 3676 << ")"; 3677 } 3678 3679 // Expressions need a newline. 3680 if (isa<Expr>(S)) 3681 OS << '\n'; 3682 3683 } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) { 3684 const CXXCtorInitializer *I = IE->getInitializer(); 3685 if (I->isBaseInitializer()) 3686 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3687 else OS << I->getAnyMember()->getName(); 3688 3689 OS << "("; 3690 if (Expr *IE = I->getInit()) 3691 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3692 OS << ")"; 3693 3694 if (I->isBaseInitializer()) 3695 OS << " (Base initializer)\n"; 3696 else OS << " (Member initializer)\n"; 3697 3698 } else if (Optional<CFGAutomaticObjDtor> DE = 3699 E.getAs<CFGAutomaticObjDtor>()) { 3700 const VarDecl *VD = DE->getVarDecl(); 3701 Helper->handleDecl(VD, OS); 3702 3703 const Type* T = VD->getType().getTypePtr(); 3704 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3705 T = RT->getPointeeType().getTypePtr(); 3706 T = T->getBaseElementTypeUnsafe(); 3707 3708 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3709 OS << " (Implicit destructor)\n"; 3710 3711 } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) { 3712 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3713 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3714 OS << " (Base object destructor)\n"; 3715 3716 } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) { 3717 const FieldDecl *FD = ME->getFieldDecl(); 3718 const Type *T = FD->getType()->getBaseElementTypeUnsafe(); 3719 OS << "this->" << FD->getName(); 3720 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3721 OS << " (Member object destructor)\n"; 3722 3723 } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) { 3724 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3725 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3726 OS << " (Temporary object destructor)\n"; 3727 } 3728} 3729 3730static void print_block(raw_ostream &OS, const CFG* cfg, 3731 const CFGBlock &B, 3732 StmtPrinterHelper* Helper, bool print_edges, 3733 bool ShowColors) { 3734 3735 if (Helper) 3736 Helper->setBlockID(B.getBlockID()); 3737 3738 // Print the header. 3739 if (ShowColors) 3740 OS.changeColor(raw_ostream::YELLOW, true); 3741 3742 OS << "\n [B" << B.getBlockID(); 3743 3744 if (&B == &cfg->getEntry()) 3745 OS << " (ENTRY)]\n"; 3746 else if (&B == &cfg->getExit()) 3747 OS << " (EXIT)]\n"; 3748 else if (&B == cfg->getIndirectGotoBlock()) 3749 OS << " (INDIRECT GOTO DISPATCH)]\n"; 3750 else 3751 OS << "]\n"; 3752 3753 if (ShowColors) 3754 OS.resetColor(); 3755 3756 // Print the label of this block. 3757 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3758 3759 if (print_edges) 3760 OS << " "; 3761 3762 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3763 OS << L->getName(); 3764 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3765 OS << "case "; 3766 C->getLHS()->printPretty(OS, Helper, 3767 PrintingPolicy(Helper->getLangOpts())); 3768 if (C->getRHS()) { 3769 OS << " ... "; 3770 C->getRHS()->printPretty(OS, Helper, 3771 PrintingPolicy(Helper->getLangOpts())); 3772 } 3773 } else if (isa<DefaultStmt>(Label)) 3774 OS << "default"; 3775 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3776 OS << "catch ("; 3777 if (CS->getExceptionDecl()) 3778 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3779 0); 3780 else 3781 OS << "..."; 3782 OS << ")"; 3783 3784 } else 3785 llvm_unreachable("Invalid label statement in CFGBlock."); 3786 3787 OS << ":\n"; 3788 } 3789 3790 // Iterate through the statements in the block and print them. 3791 unsigned j = 1; 3792 3793 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3794 I != E ; ++I, ++j ) { 3795 3796 // Print the statement # in the basic block and the statement itself. 3797 if (print_edges) 3798 OS << " "; 3799 3800 OS << llvm::format("%3d", j) << ": "; 3801 3802 if (Helper) 3803 Helper->setStmtID(j); 3804 3805 print_elem(OS, Helper, *I); 3806 } 3807 3808 // Print the terminator of this block. 3809 if (B.getTerminator()) { 3810 if (ShowColors) 3811 OS.changeColor(raw_ostream::GREEN); 3812 3813 OS << " T: "; 3814 3815 if (Helper) Helper->setBlockID(-1); 3816 3817 PrintingPolicy PP(Helper ? Helper->getLangOpts() : LangOptions()); 3818 CFGBlockTerminatorPrint TPrinter(OS, Helper, PP); 3819 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3820 OS << '\n'; 3821 3822 if (ShowColors) 3823 OS.resetColor(); 3824 } 3825 3826 if (print_edges) { 3827 // Print the predecessors of this block. 3828 if (!B.pred_empty()) { 3829 const raw_ostream::Colors Color = raw_ostream::BLUE; 3830 if (ShowColors) 3831 OS.changeColor(Color); 3832 OS << " Preds " ; 3833 if (ShowColors) 3834 OS.resetColor(); 3835 OS << '(' << B.pred_size() << "):"; 3836 unsigned i = 0; 3837 3838 if (ShowColors) 3839 OS.changeColor(Color); 3840 3841 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3842 I != E; ++I, ++i) { 3843 3844 if (i % 10 == 8) 3845 OS << "\n "; 3846 3847 OS << " B" << (*I)->getBlockID(); 3848 } 3849 3850 if (ShowColors) 3851 OS.resetColor(); 3852 3853 OS << '\n'; 3854 } 3855 3856 // Print the successors of this block. 3857 if (!B.succ_empty()) { 3858 const raw_ostream::Colors Color = raw_ostream::MAGENTA; 3859 if (ShowColors) 3860 OS.changeColor(Color); 3861 OS << " Succs "; 3862 if (ShowColors) 3863 OS.resetColor(); 3864 OS << '(' << B.succ_size() << "):"; 3865 unsigned i = 0; 3866 3867 if (ShowColors) 3868 OS.changeColor(Color); 3869 3870 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3871 I != E; ++I, ++i) { 3872 3873 if (i % 10 == 8) 3874 OS << "\n "; 3875 3876 if (*I) 3877 OS << " B" << (*I)->getBlockID(); 3878 else 3879 OS << " NULL"; 3880 } 3881 3882 if (ShowColors) 3883 OS.resetColor(); 3884 OS << '\n'; 3885 } 3886 } 3887} 3888 3889 3890/// dump - A simple pretty printer of a CFG that outputs to stderr. 3891void CFG::dump(const LangOptions &LO, bool ShowColors) const { 3892 print(llvm::errs(), LO, ShowColors); 3893} 3894 3895/// print - A simple pretty printer of a CFG that outputs to an ostream. 3896void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const { 3897 StmtPrinterHelper Helper(this, LO); 3898 3899 // Print the entry block. 3900 print_block(OS, this, getEntry(), &Helper, true, ShowColors); 3901 3902 // Iterate through the CFGBlocks and print them one by one. 3903 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3904 // Skip the entry block, because we already printed it. 3905 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3906 continue; 3907 3908 print_block(OS, this, **I, &Helper, true, ShowColors); 3909 } 3910 3911 // Print the exit block. 3912 print_block(OS, this, getExit(), &Helper, true, ShowColors); 3913 OS << '\n'; 3914 OS.flush(); 3915} 3916 3917/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3918void CFGBlock::dump(const CFG* cfg, const LangOptions &LO, 3919 bool ShowColors) const { 3920 print(llvm::errs(), cfg, LO, ShowColors); 3921} 3922 3923/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3924/// Generally this will only be called from CFG::print. 3925void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 3926 const LangOptions &LO, bool ShowColors) const { 3927 StmtPrinterHelper Helper(cfg, LO); 3928 print_block(OS, cfg, *this, &Helper, true, ShowColors); 3929 OS << '\n'; 3930} 3931 3932/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3933void CFGBlock::printTerminator(raw_ostream &OS, 3934 const LangOptions &LO) const { 3935 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3936 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3937} 3938 3939Stmt *CFGBlock::getTerminatorCondition() { 3940 Stmt *Terminator = this->Terminator; 3941 if (!Terminator) 3942 return NULL; 3943 3944 Expr *E = NULL; 3945 3946 switch (Terminator->getStmtClass()) { 3947 default: 3948 break; 3949 3950 case Stmt::ForStmtClass: 3951 E = cast<ForStmt>(Terminator)->getCond(); 3952 break; 3953 3954 case Stmt::WhileStmtClass: 3955 E = cast<WhileStmt>(Terminator)->getCond(); 3956 break; 3957 3958 case Stmt::DoStmtClass: 3959 E = cast<DoStmt>(Terminator)->getCond(); 3960 break; 3961 3962 case Stmt::IfStmtClass: 3963 E = cast<IfStmt>(Terminator)->getCond(); 3964 break; 3965 3966 case Stmt::ChooseExprClass: 3967 E = cast<ChooseExpr>(Terminator)->getCond(); 3968 break; 3969 3970 case Stmt::IndirectGotoStmtClass: 3971 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3972 break; 3973 3974 case Stmt::SwitchStmtClass: 3975 E = cast<SwitchStmt>(Terminator)->getCond(); 3976 break; 3977 3978 case Stmt::BinaryConditionalOperatorClass: 3979 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3980 break; 3981 3982 case Stmt::ConditionalOperatorClass: 3983 E = cast<ConditionalOperator>(Terminator)->getCond(); 3984 break; 3985 3986 case Stmt::BinaryOperatorClass: // '&&' and '||' 3987 E = cast<BinaryOperator>(Terminator)->getLHS(); 3988 break; 3989 3990 case Stmt::ObjCForCollectionStmtClass: 3991 return Terminator; 3992 } 3993 3994 return E ? E->IgnoreParens() : NULL; 3995} 3996 3997//===----------------------------------------------------------------------===// 3998// CFG Graphviz Visualization 3999//===----------------------------------------------------------------------===// 4000 4001 4002#ifndef NDEBUG 4003static StmtPrinterHelper* GraphHelper; 4004#endif 4005 4006void CFG::viewCFG(const LangOptions &LO) const { 4007#ifndef NDEBUG 4008 StmtPrinterHelper H(this, LO); 4009 GraphHelper = &H; 4010 llvm::ViewGraph(this,"CFG"); 4011 GraphHelper = NULL; 4012#endif 4013} 4014 4015namespace llvm { 4016template<> 4017struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 4018 4019 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 4020 4021 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 4022 4023#ifndef NDEBUG 4024 std::string OutSStr; 4025 llvm::raw_string_ostream Out(OutSStr); 4026 print_block(Out,Graph, *Node, GraphHelper, false, false); 4027 std::string& OutStr = Out.str(); 4028 4029 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 4030 4031 // Process string output to make it nicer... 4032 for (unsigned i = 0; i != OutStr.length(); ++i) 4033 if (OutStr[i] == '\n') { // Left justify 4034 OutStr[i] = '\\'; 4035 OutStr.insert(OutStr.begin()+i+1, 'l'); 4036 } 4037 4038 return OutStr; 4039#else 4040 return ""; 4041#endif 4042 } 4043}; 4044} // end namespace llvm 4045