CFG.cpp revision 0f5c5c60e9806d13f0907cd99d7204ffab0e08f7
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 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 // FIXME: The expression inside a CXXDefaultArgExpr is owned by the 1089 // called function's declaration, not by the caller. If we simply add 1090 // this expression to the CFG, we could end up with the same Expr 1091 // appearing multiple times. 1092 // PR13385 / <rdar://problem/12156507> 1093 return VisitStmt(S, asc); 1094 1095 case Stmt::CXXBindTemporaryExprClass: 1096 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 1097 1098 case Stmt::CXXConstructExprClass: 1099 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 1100 1101 case Stmt::CXXFunctionalCastExprClass: 1102 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 1103 1104 case Stmt::CXXTemporaryObjectExprClass: 1105 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 1106 1107 case Stmt::CXXThrowExprClass: 1108 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 1109 1110 case Stmt::CXXTryStmtClass: 1111 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 1112 1113 case Stmt::CXXForRangeStmtClass: 1114 return VisitCXXForRangeStmt(cast<CXXForRangeStmt>(S)); 1115 1116 case Stmt::DeclStmtClass: 1117 return VisitDeclStmt(cast<DeclStmt>(S)); 1118 1119 case Stmt::DefaultStmtClass: 1120 return VisitDefaultStmt(cast<DefaultStmt>(S)); 1121 1122 case Stmt::DoStmtClass: 1123 return VisitDoStmt(cast<DoStmt>(S)); 1124 1125 case Stmt::ForStmtClass: 1126 return VisitForStmt(cast<ForStmt>(S)); 1127 1128 case Stmt::GotoStmtClass: 1129 return VisitGotoStmt(cast<GotoStmt>(S)); 1130 1131 case Stmt::IfStmtClass: 1132 return VisitIfStmt(cast<IfStmt>(S)); 1133 1134 case Stmt::ImplicitCastExprClass: 1135 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 1136 1137 case Stmt::IndirectGotoStmtClass: 1138 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 1139 1140 case Stmt::LabelStmtClass: 1141 return VisitLabelStmt(cast<LabelStmt>(S)); 1142 1143 case Stmt::LambdaExprClass: 1144 return VisitLambdaExpr(cast<LambdaExpr>(S), asc); 1145 1146 case Stmt::MemberExprClass: 1147 return VisitMemberExpr(cast<MemberExpr>(S), asc); 1148 1149 case Stmt::NullStmtClass: 1150 return Block; 1151 1152 case Stmt::ObjCAtCatchStmtClass: 1153 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 1154 1155 case Stmt::ObjCAutoreleasePoolStmtClass: 1156 return VisitObjCAutoreleasePoolStmt(cast<ObjCAutoreleasePoolStmt>(S)); 1157 1158 case Stmt::ObjCAtSynchronizedStmtClass: 1159 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 1160 1161 case Stmt::ObjCAtThrowStmtClass: 1162 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 1163 1164 case Stmt::ObjCAtTryStmtClass: 1165 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 1166 1167 case Stmt::ObjCForCollectionStmtClass: 1168 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 1169 1170 case Stmt::OpaqueValueExprClass: 1171 return Block; 1172 1173 case Stmt::PseudoObjectExprClass: 1174 return VisitPseudoObjectExpr(cast<PseudoObjectExpr>(S)); 1175 1176 case Stmt::ReturnStmtClass: 1177 return VisitReturnStmt(cast<ReturnStmt>(S)); 1178 1179 case Stmt::UnaryExprOrTypeTraitExprClass: 1180 return VisitUnaryExprOrTypeTraitExpr(cast<UnaryExprOrTypeTraitExpr>(S), 1181 asc); 1182 1183 case Stmt::StmtExprClass: 1184 return VisitStmtExpr(cast<StmtExpr>(S), asc); 1185 1186 case Stmt::SwitchStmtClass: 1187 return VisitSwitchStmt(cast<SwitchStmt>(S)); 1188 1189 case Stmt::UnaryOperatorClass: 1190 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 1191 1192 case Stmt::WhileStmtClass: 1193 return VisitWhileStmt(cast<WhileStmt>(S)); 1194 } 1195} 1196 1197CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 1198 if (asc.alwaysAdd(*this, S)) { 1199 autoCreateBlock(); 1200 appendStmt(Block, S); 1201 } 1202 1203 return VisitChildren(S); 1204} 1205 1206/// VisitChildren - Visit the children of a Stmt. 1207CFGBlock *CFGBuilder::VisitChildren(Stmt *S) { 1208 CFGBlock *B = Block; 1209 1210 // Visit the children in their reverse order so that they appear in 1211 // left-to-right (natural) order in the CFG. 1212 reverse_children RChildren(S); 1213 for (reverse_children::iterator I = RChildren.begin(), E = RChildren.end(); 1214 I != E; ++I) { 1215 if (Stmt *Child = *I) 1216 if (CFGBlock *R = Visit(Child)) 1217 B = R; 1218 } 1219 return B; 1220} 1221 1222CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 1223 AddStmtChoice asc) { 1224 AddressTakenLabels.insert(A->getLabel()); 1225 1226 if (asc.alwaysAdd(*this, A)) { 1227 autoCreateBlock(); 1228 appendStmt(Block, A); 1229 } 1230 1231 return Block; 1232} 1233 1234CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 1235 AddStmtChoice asc) { 1236 if (asc.alwaysAdd(*this, U)) { 1237 autoCreateBlock(); 1238 appendStmt(Block, U); 1239 } 1240 1241 return Visit(U->getSubExpr(), AddStmtChoice()); 1242} 1243 1244CFGBlock *CFGBuilder::VisitLogicalOperator(BinaryOperator *B) { 1245 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1246 appendStmt(ConfluenceBlock, B); 1247 1248 if (badCFG) 1249 return 0; 1250 1251 return VisitLogicalOperator(B, 0, ConfluenceBlock, ConfluenceBlock).first; 1252} 1253 1254std::pair<CFGBlock*, CFGBlock*> 1255CFGBuilder::VisitLogicalOperator(BinaryOperator *B, 1256 Stmt *Term, 1257 CFGBlock *TrueBlock, 1258 CFGBlock *FalseBlock) { 1259 1260 // Introspect the RHS. If it is a nested logical operation, we recursively 1261 // build the CFG using this function. Otherwise, resort to default 1262 // CFG construction behavior. 1263 Expr *RHS = B->getRHS()->IgnoreParens(); 1264 CFGBlock *RHSBlock, *ExitBlock; 1265 1266 do { 1267 if (BinaryOperator *B_RHS = dyn_cast<BinaryOperator>(RHS)) 1268 if (B_RHS->isLogicalOp()) { 1269 llvm::tie(RHSBlock, ExitBlock) = 1270 VisitLogicalOperator(B_RHS, Term, TrueBlock, FalseBlock); 1271 break; 1272 } 1273 1274 // The RHS is not a nested logical operation. Don't push the terminator 1275 // down further, but instead visit RHS and construct the respective 1276 // pieces of the CFG, and link up the RHSBlock with the terminator 1277 // we have been provided. 1278 ExitBlock = RHSBlock = createBlock(false); 1279 1280 if (!Term) { 1281 assert(TrueBlock == FalseBlock); 1282 addSuccessor(RHSBlock, TrueBlock); 1283 } 1284 else { 1285 RHSBlock->setTerminator(Term); 1286 TryResult KnownVal = tryEvaluateBool(RHS); 1287 addSuccessor(RHSBlock, KnownVal.isFalse() ? NULL : TrueBlock); 1288 addSuccessor(RHSBlock, KnownVal.isTrue() ? NULL : FalseBlock); 1289 } 1290 1291 Block = RHSBlock; 1292 RHSBlock = addStmt(RHS); 1293 } 1294 while (false); 1295 1296 if (badCFG) 1297 return std::make_pair((CFGBlock*)0, (CFGBlock*)0); 1298 1299 // Generate the blocks for evaluating the LHS. 1300 Expr *LHS = B->getLHS()->IgnoreParens(); 1301 1302 if (BinaryOperator *B_LHS = dyn_cast<BinaryOperator>(LHS)) 1303 if (B_LHS->isLogicalOp()) { 1304 if (B->getOpcode() == BO_LOr) 1305 FalseBlock = RHSBlock; 1306 else 1307 TrueBlock = RHSBlock; 1308 1309 // For the LHS, treat 'B' as the terminator that we want to sink 1310 // into the nested branch. The RHS always gets the top-most 1311 // terminator. 1312 return VisitLogicalOperator(B_LHS, B, TrueBlock, FalseBlock); 1313 } 1314 1315 // Create the block evaluating the LHS. 1316 // This contains the '&&' or '||' as the terminator. 1317 CFGBlock *LHSBlock = createBlock(false); 1318 LHSBlock->setTerminator(B); 1319 1320 Block = LHSBlock; 1321 CFGBlock *EntryLHSBlock = addStmt(LHS); 1322 1323 if (badCFG) 1324 return std::make_pair((CFGBlock*)0, (CFGBlock*)0); 1325 1326 // See if this is a known constant. 1327 TryResult KnownVal = tryEvaluateBool(LHS); 1328 1329 // Now link the LHSBlock with RHSBlock. 1330 if (B->getOpcode() == BO_LOr) { 1331 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : TrueBlock); 1332 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : RHSBlock); 1333 } else { 1334 assert(B->getOpcode() == BO_LAnd); 1335 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1336 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : FalseBlock); 1337 } 1338 1339 return std::make_pair(EntryLHSBlock, ExitBlock); 1340} 1341 1342 1343CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 1344 AddStmtChoice asc) { 1345 // && or || 1346 if (B->isLogicalOp()) 1347 return VisitLogicalOperator(B); 1348 1349 if (B->getOpcode() == BO_Comma) { // , 1350 autoCreateBlock(); 1351 appendStmt(Block, B); 1352 addStmt(B->getRHS()); 1353 return addStmt(B->getLHS()); 1354 } 1355 1356 if (B->isAssignmentOp()) { 1357 if (asc.alwaysAdd(*this, B)) { 1358 autoCreateBlock(); 1359 appendStmt(Block, B); 1360 } 1361 Visit(B->getLHS()); 1362 return Visit(B->getRHS()); 1363 } 1364 1365 if (asc.alwaysAdd(*this, B)) { 1366 autoCreateBlock(); 1367 appendStmt(Block, B); 1368 } 1369 1370 CFGBlock *RBlock = Visit(B->getRHS()); 1371 CFGBlock *LBlock = Visit(B->getLHS()); 1372 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1373 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1374 // return RBlock. Otherwise we'll incorrectly return NULL. 1375 return (LBlock ? LBlock : RBlock); 1376} 1377 1378CFGBlock *CFGBuilder::VisitNoRecurse(Expr *E, AddStmtChoice asc) { 1379 if (asc.alwaysAdd(*this, E)) { 1380 autoCreateBlock(); 1381 appendStmt(Block, E); 1382 } 1383 return Block; 1384} 1385 1386CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1387 // "break" is a control-flow statement. Thus we stop processing the current 1388 // block. 1389 if (badCFG) 1390 return 0; 1391 1392 // Now create a new block that ends with the break statement. 1393 Block = createBlock(false); 1394 Block->setTerminator(B); 1395 1396 // If there is no target for the break, then we are looking at an incomplete 1397 // AST. This means that the CFG cannot be constructed. 1398 if (BreakJumpTarget.block) { 1399 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1400 addSuccessor(Block, BreakJumpTarget.block); 1401 } else 1402 badCFG = true; 1403 1404 1405 return Block; 1406} 1407 1408static bool CanThrow(Expr *E, ASTContext &Ctx) { 1409 QualType Ty = E->getType(); 1410 if (Ty->isFunctionPointerType()) 1411 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1412 else if (Ty->isBlockPointerType()) 1413 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1414 1415 const FunctionType *FT = Ty->getAs<FunctionType>(); 1416 if (FT) { 1417 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1418 if (!isUnresolvedExceptionSpec(Proto->getExceptionSpecType()) && 1419 Proto->isNothrow(Ctx)) 1420 return false; 1421 } 1422 return true; 1423} 1424 1425CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1426 // Compute the callee type. 1427 QualType calleeType = C->getCallee()->getType(); 1428 if (calleeType == Context->BoundMemberTy) { 1429 QualType boundType = Expr::findBoundMemberType(C->getCallee()); 1430 1431 // We should only get a null bound type if processing a dependent 1432 // CFG. Recover by assuming nothing. 1433 if (!boundType.isNull()) calleeType = boundType; 1434 } 1435 1436 // If this is a call to a no-return function, this stops the block here. 1437 bool NoReturn = getFunctionExtInfo(*calleeType).getNoReturn(); 1438 1439 bool AddEHEdge = false; 1440 1441 // Languages without exceptions are assumed to not throw. 1442 if (Context->getLangOpts().Exceptions) { 1443 if (BuildOpts.AddEHEdges) 1444 AddEHEdge = true; 1445 } 1446 1447 if (FunctionDecl *FD = C->getDirectCallee()) { 1448 if (FD->isNoReturn()) 1449 NoReturn = true; 1450 if (FD->hasAttr<NoThrowAttr>()) 1451 AddEHEdge = false; 1452 } 1453 1454 if (!CanThrow(C->getCallee(), *Context)) 1455 AddEHEdge = false; 1456 1457 if (!NoReturn && !AddEHEdge) 1458 return VisitStmt(C, asc.withAlwaysAdd(true)); 1459 1460 if (Block) { 1461 Succ = Block; 1462 if (badCFG) 1463 return 0; 1464 } 1465 1466 if (NoReturn) 1467 Block = createNoReturnBlock(); 1468 else 1469 Block = createBlock(); 1470 1471 appendStmt(Block, C); 1472 1473 if (AddEHEdge) { 1474 // Add exceptional edges. 1475 if (TryTerminatedBlock) 1476 addSuccessor(Block, TryTerminatedBlock); 1477 else 1478 addSuccessor(Block, &cfg->getExit()); 1479 } 1480 1481 return VisitChildren(C); 1482} 1483 1484CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1485 AddStmtChoice asc) { 1486 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1487 appendStmt(ConfluenceBlock, C); 1488 if (badCFG) 1489 return 0; 1490 1491 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1492 Succ = ConfluenceBlock; 1493 Block = NULL; 1494 CFGBlock *LHSBlock = Visit(C->getLHS(), alwaysAdd); 1495 if (badCFG) 1496 return 0; 1497 1498 Succ = ConfluenceBlock; 1499 Block = NULL; 1500 CFGBlock *RHSBlock = Visit(C->getRHS(), alwaysAdd); 1501 if (badCFG) 1502 return 0; 1503 1504 Block = createBlock(false); 1505 // See if this is a known constant. 1506 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1507 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1508 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1509 Block->setTerminator(C); 1510 return addStmt(C->getCond()); 1511} 1512 1513 1514CFGBlock *CFGBuilder::VisitCompoundStmt(CompoundStmt *C) { 1515 addLocalScopeAndDtors(C); 1516 CFGBlock *LastBlock = Block; 1517 1518 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1519 I != E; ++I ) { 1520 // If we hit a segment of code just containing ';' (NullStmts), we can 1521 // get a null block back. In such cases, just use the LastBlock 1522 if (CFGBlock *newBlock = addStmt(*I)) 1523 LastBlock = newBlock; 1524 1525 if (badCFG) 1526 return NULL; 1527 } 1528 1529 return LastBlock; 1530} 1531 1532CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1533 AddStmtChoice asc) { 1534 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1535 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1536 1537 // Create the confluence block that will "merge" the results of the ternary 1538 // expression. 1539 CFGBlock *ConfluenceBlock = Block ? Block : createBlock(); 1540 appendStmt(ConfluenceBlock, C); 1541 if (badCFG) 1542 return 0; 1543 1544 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1545 1546 // Create a block for the LHS expression if there is an LHS expression. A 1547 // GCC extension allows LHS to be NULL, causing the condition to be the 1548 // value that is returned instead. 1549 // e.g: x ?: y is shorthand for: x ? x : y; 1550 Succ = ConfluenceBlock; 1551 Block = NULL; 1552 CFGBlock *LHSBlock = 0; 1553 const Expr *trueExpr = C->getTrueExpr(); 1554 if (trueExpr != opaqueValue) { 1555 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1556 if (badCFG) 1557 return 0; 1558 Block = NULL; 1559 } 1560 else 1561 LHSBlock = ConfluenceBlock; 1562 1563 // Create the block for the RHS expression. 1564 Succ = ConfluenceBlock; 1565 CFGBlock *RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1566 if (badCFG) 1567 return 0; 1568 1569 // If the condition is a logical '&&' or '||', build a more accurate CFG. 1570 if (BinaryOperator *Cond = 1571 dyn_cast<BinaryOperator>(C->getCond()->IgnoreParens())) 1572 if (Cond->isLogicalOp()) 1573 return VisitLogicalOperator(Cond, C, LHSBlock, RHSBlock).first; 1574 1575 // Create the block that will contain the condition. 1576 Block = createBlock(false); 1577 1578 // See if this is a known constant. 1579 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1580 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1581 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1582 Block->setTerminator(C); 1583 Expr *condExpr = C->getCond(); 1584 1585 if (opaqueValue) { 1586 // Run the condition expression if it's not trivially expressed in 1587 // terms of the opaque value (or if there is no opaque value). 1588 if (condExpr != opaqueValue) 1589 addStmt(condExpr); 1590 1591 // Before that, run the common subexpression if there was one. 1592 // At least one of this or the above will be run. 1593 return addStmt(BCO->getCommon()); 1594 } 1595 1596 return addStmt(condExpr); 1597} 1598 1599CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1600 // Check if the Decl is for an __label__. If so, elide it from the 1601 // CFG entirely. 1602 if (isa<LabelDecl>(*DS->decl_begin())) 1603 return Block; 1604 1605 // This case also handles static_asserts. 1606 if (DS->isSingleDecl()) 1607 return VisitDeclSubExpr(DS); 1608 1609 CFGBlock *B = 0; 1610 1611 // Build an individual DeclStmt for each decl. 1612 for (DeclStmt::reverse_decl_iterator I = DS->decl_rbegin(), 1613 E = DS->decl_rend(); 1614 I != E; ++I) { 1615 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1616 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1617 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1618 1619 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1620 // automatically freed with the CFG. 1621 DeclGroupRef DG(*I); 1622 Decl *D = *I; 1623 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1624 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1625 1626 // Append the fake DeclStmt to block. 1627 B = VisitDeclSubExpr(DSNew); 1628 } 1629 1630 return B; 1631} 1632 1633/// VisitDeclSubExpr - Utility method to add block-level expressions for 1634/// DeclStmts and initializers in them. 1635CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt *DS) { 1636 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1637 Decl *D = DS->getSingleDecl(); 1638 1639 if (isa<StaticAssertDecl>(D)) { 1640 // static_asserts aren't added to the CFG because they do not impact 1641 // runtime semantics. 1642 return Block; 1643 } 1644 1645 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1646 1647 if (!VD) { 1648 autoCreateBlock(); 1649 appendStmt(Block, DS); 1650 return Block; 1651 } 1652 1653 bool IsReference = false; 1654 bool HasTemporaries = false; 1655 1656 // Guard static initializers under a branch. 1657 CFGBlock *blockBeforeInit = 0; 1658 1659 // Destructors of temporaries in initialization expression should be called 1660 // after initialization finishes. 1661 Expr *Init = VD->getInit(); 1662 if (Init) { 1663 if (BuildOpts.AddStaticInitBranches && VD->isStaticLocal()) { 1664 // For static variables, we need to create a branch to track 1665 // whether or not they are initialized. 1666 if (Block) { 1667 Succ = Block; 1668 Block = 0; 1669 if (badCFG) 1670 return 0; 1671 } 1672 blockBeforeInit = Succ; 1673 } 1674 1675 IsReference = VD->getType()->isReferenceType(); 1676 HasTemporaries = isa<ExprWithCleanups>(Init); 1677 1678 if (BuildOpts.AddTemporaryDtors && HasTemporaries) { 1679 // Generate destructors for temporaries in initialization expression. 1680 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1681 IsReference); 1682 } 1683 } 1684 1685 autoCreateBlock(); 1686 appendStmt(Block, DS); 1687 1688 // Keep track of the last non-null block, as 'Block' can be nulled out 1689 // if the initializer expression is something like a 'while' in a 1690 // statement-expression. 1691 CFGBlock *LastBlock = Block; 1692 1693 if (Init) { 1694 if (HasTemporaries) { 1695 // For expression with temporaries go directly to subexpression to omit 1696 // generating destructors for the second time. 1697 ExprWithCleanups *EC = cast<ExprWithCleanups>(Init); 1698 if (CFGBlock *newBlock = Visit(EC->getSubExpr())) 1699 LastBlock = newBlock; 1700 } 1701 else { 1702 if (CFGBlock *newBlock = Visit(Init)) 1703 LastBlock = newBlock; 1704 } 1705 } 1706 1707 // If the type of VD is a VLA, then we must process its size expressions. 1708 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1709 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) { 1710 if (CFGBlock *newBlock = addStmt(VA->getSizeExpr())) 1711 LastBlock = newBlock; 1712 } 1713 1714 // Remove variable from local scope. 1715 if (ScopePos && VD == *ScopePos) 1716 ++ScopePos; 1717 1718 CFGBlock *B = LastBlock; 1719 if (blockBeforeInit) { 1720 Succ = B; 1721 Block = createBlock(false); 1722 Block->setTerminator(DS); 1723 addSuccessor(Block, blockBeforeInit); 1724 addSuccessor(Block, B); 1725 B = Block; 1726 } 1727 1728 return B; 1729} 1730 1731CFGBlock *CFGBuilder::VisitIfStmt(IfStmt *I) { 1732 // We may see an if statement in the middle of a basic block, or it may be the 1733 // first statement we are processing. In either case, we create a new basic 1734 // block. First, we create the blocks for the then...else statements, and 1735 // then we create the block containing the if statement. If we were in the 1736 // middle of a block, we stop processing that block. That block is then the 1737 // implicit successor for the "then" and "else" clauses. 1738 1739 // Save local scope position because in case of condition variable ScopePos 1740 // won't be restored when traversing AST. 1741 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1742 1743 // Create local scope for possible condition variable. 1744 // Store scope position. Add implicit destructor. 1745 if (VarDecl *VD = I->getConditionVariable()) { 1746 LocalScope::const_iterator BeginScopePos = ScopePos; 1747 addLocalScopeForVarDecl(VD); 1748 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1749 } 1750 1751 // The block we were processing is now finished. Make it the successor 1752 // block. 1753 if (Block) { 1754 Succ = Block; 1755 if (badCFG) 1756 return 0; 1757 } 1758 1759 // Process the false branch. 1760 CFGBlock *ElseBlock = Succ; 1761 1762 if (Stmt *Else = I->getElse()) { 1763 SaveAndRestore<CFGBlock*> sv(Succ); 1764 1765 // NULL out Block so that the recursive call to Visit will 1766 // create a new basic block. 1767 Block = NULL; 1768 1769 // If branch is not a compound statement create implicit scope 1770 // and add destructors. 1771 if (!isa<CompoundStmt>(Else)) 1772 addLocalScopeAndDtors(Else); 1773 1774 ElseBlock = addStmt(Else); 1775 1776 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1777 ElseBlock = sv.get(); 1778 else if (Block) { 1779 if (badCFG) 1780 return 0; 1781 } 1782 } 1783 1784 // Process the true branch. 1785 CFGBlock *ThenBlock; 1786 { 1787 Stmt *Then = I->getThen(); 1788 assert(Then); 1789 SaveAndRestore<CFGBlock*> sv(Succ); 1790 Block = NULL; 1791 1792 // If branch is not a compound statement create implicit scope 1793 // and add destructors. 1794 if (!isa<CompoundStmt>(Then)) 1795 addLocalScopeAndDtors(Then); 1796 1797 ThenBlock = addStmt(Then); 1798 1799 if (!ThenBlock) { 1800 // We can reach here if the "then" body has all NullStmts. 1801 // Create an empty block so we can distinguish between true and false 1802 // branches in path-sensitive analyses. 1803 ThenBlock = createBlock(false); 1804 addSuccessor(ThenBlock, sv.get()); 1805 } else if (Block) { 1806 if (badCFG) 1807 return 0; 1808 } 1809 } 1810 1811 // Specially handle "if (expr1 || ...)" and "if (expr1 && ...)" by 1812 // having these handle the actual control-flow jump. Note that 1813 // if we introduce a condition variable, e.g. "if (int x = exp1 || exp2)" 1814 // we resort to the old control-flow behavior. This special handling 1815 // removes infeasible paths from the control-flow graph by having the 1816 // control-flow transfer of '&&' or '||' go directly into the then/else 1817 // blocks directly. 1818 if (!I->getConditionVariable()) 1819 if (BinaryOperator *Cond = 1820 dyn_cast<BinaryOperator>(I->getCond()->IgnoreParens())) 1821 if (Cond->isLogicalOp()) 1822 return VisitLogicalOperator(Cond, I, ThenBlock, ElseBlock).first; 1823 1824 // Now create a new block containing the if statement. 1825 Block = createBlock(false); 1826 1827 // Set the terminator of the new block to the If statement. 1828 Block->setTerminator(I); 1829 1830 // See if this is a known constant. 1831 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1832 1833 // Now add the successors. 1834 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1835 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1836 1837 // Add the condition as the last statement in the new block. This may create 1838 // new blocks as the condition may contain control-flow. Any newly created 1839 // blocks will be pointed to be "Block". 1840 CFGBlock *LastBlock = addStmt(I->getCond()); 1841 1842 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1843 // and the condition variable initialization to the CFG. 1844 if (VarDecl *VD = I->getConditionVariable()) { 1845 if (Expr *Init = VD->getInit()) { 1846 autoCreateBlock(); 1847 appendStmt(Block, I->getConditionVariableDeclStmt()); 1848 LastBlock = addStmt(Init); 1849 } 1850 } 1851 1852 return LastBlock; 1853} 1854 1855 1856CFGBlock *CFGBuilder::VisitReturnStmt(ReturnStmt *R) { 1857 // If we were in the middle of a block we stop processing that block. 1858 // 1859 // NOTE: If a "return" appears in the middle of a block, this means that the 1860 // code afterwards is DEAD (unreachable). We still keep a basic block 1861 // for that code; a simple "mark-and-sweep" from the entry block will be 1862 // able to report such dead blocks. 1863 1864 // Create the new block. 1865 Block = createBlock(false); 1866 1867 // The Exit block is the only successor. 1868 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1869 addSuccessor(Block, &cfg->getExit()); 1870 1871 // Add the return statement to the block. This may create new blocks if R 1872 // contains control-flow (short-circuit operations). 1873 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1874} 1875 1876CFGBlock *CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1877 // Get the block of the labeled statement. Add it to our map. 1878 addStmt(L->getSubStmt()); 1879 CFGBlock *LabelBlock = Block; 1880 1881 if (!LabelBlock) // This can happen when the body is empty, i.e. 1882 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1883 1884 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1885 "label already in map"); 1886 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1887 1888 // Labels partition blocks, so this is the end of the basic block we were 1889 // processing (L is the block's label). Because this is label (and we have 1890 // already processed the substatement) there is no extra control-flow to worry 1891 // about. 1892 LabelBlock->setLabel(L); 1893 if (badCFG) 1894 return 0; 1895 1896 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1897 Block = NULL; 1898 1899 // This block is now the implicit successor of other blocks. 1900 Succ = LabelBlock; 1901 1902 return LabelBlock; 1903} 1904 1905CFGBlock *CFGBuilder::VisitLambdaExpr(LambdaExpr *E, AddStmtChoice asc) { 1906 CFGBlock *LastBlock = VisitNoRecurse(E, asc); 1907 for (LambdaExpr::capture_init_iterator it = E->capture_init_begin(), 1908 et = E->capture_init_end(); it != et; ++it) { 1909 if (Expr *Init = *it) { 1910 CFGBlock *Tmp = Visit(Init); 1911 if (Tmp != 0) 1912 LastBlock = Tmp; 1913 } 1914 } 1915 return LastBlock; 1916} 1917 1918CFGBlock *CFGBuilder::VisitGotoStmt(GotoStmt *G) { 1919 // Goto is a control-flow statement. Thus we stop processing the current 1920 // block and create a new one. 1921 1922 Block = createBlock(false); 1923 Block->setTerminator(G); 1924 1925 // If we already know the mapping to the label block add the successor now. 1926 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1927 1928 if (I == LabelMap.end()) 1929 // We will need to backpatch this block later. 1930 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1931 else { 1932 JumpTarget JT = I->second; 1933 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1934 addSuccessor(Block, JT.block); 1935 } 1936 1937 return Block; 1938} 1939 1940CFGBlock *CFGBuilder::VisitForStmt(ForStmt *F) { 1941 CFGBlock *LoopSuccessor = NULL; 1942 1943 // Save local scope position because in case of condition variable ScopePos 1944 // won't be restored when traversing AST. 1945 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1946 1947 // Create local scope for init statement and possible condition variable. 1948 // Add destructor for init statement and condition variable. 1949 // Store scope position for continue statement. 1950 if (Stmt *Init = F->getInit()) 1951 addLocalScopeForStmt(Init); 1952 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1953 1954 if (VarDecl *VD = F->getConditionVariable()) 1955 addLocalScopeForVarDecl(VD); 1956 LocalScope::const_iterator ContinueScopePos = ScopePos; 1957 1958 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1959 1960 // "for" is a control-flow statement. Thus we stop processing the current 1961 // block. 1962 if (Block) { 1963 if (badCFG) 1964 return 0; 1965 LoopSuccessor = Block; 1966 } else 1967 LoopSuccessor = Succ; 1968 1969 // Save the current value for the break targets. 1970 // All breaks should go to the code following the loop. 1971 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1972 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1973 1974 CFGBlock *BodyBlock = 0, *TransitionBlock = 0; 1975 1976 // Now create the loop body. 1977 { 1978 assert(F->getBody()); 1979 1980 // Save the current values for Block, Succ, continue and break targets. 1981 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1982 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1983 1984 // Create an empty block to represent the transition block for looping back 1985 // to the head of the loop. If we have increment code, it will 1986 // go in this block as well. 1987 Block = Succ = TransitionBlock = createBlock(false); 1988 TransitionBlock->setLoopTarget(F); 1989 1990 if (Stmt *I = F->getInc()) { 1991 // Generate increment code in its own basic block. This is the target of 1992 // continue statements. 1993 Succ = addStmt(I); 1994 } 1995 1996 // Finish up the increment (or empty) block if it hasn't been already. 1997 if (Block) { 1998 assert(Block == Succ); 1999 if (badCFG) 2000 return 0; 2001 Block = 0; 2002 } 2003 2004 // The starting block for the loop increment is the block that should 2005 // represent the 'loop target' for looping back to the start of the loop. 2006 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 2007 ContinueJumpTarget.block->setLoopTarget(F); 2008 2009 // Loop body should end with destructor of Condition variable (if any). 2010 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 2011 2012 // If body is not a compound statement create implicit scope 2013 // and add destructors. 2014 if (!isa<CompoundStmt>(F->getBody())) 2015 addLocalScopeAndDtors(F->getBody()); 2016 2017 // Now populate the body block, and in the process create new blocks as we 2018 // walk the body of the loop. 2019 BodyBlock = addStmt(F->getBody()); 2020 2021 if (!BodyBlock) { 2022 // In the case of "for (...;...;...);" we can have a null BodyBlock. 2023 // Use the continue jump target as the proxy for the body. 2024 BodyBlock = ContinueJumpTarget.block; 2025 } 2026 else if (badCFG) 2027 return 0; 2028 } 2029 2030 // Because of short-circuit evaluation, the condition of the loop can span 2031 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2032 // evaluate the condition. 2033 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0; 2034 2035 do { 2036 Expr *C = F->getCond(); 2037 2038 // Specially handle logical operators, which have a slightly 2039 // more optimal CFG representation. 2040 if (BinaryOperator *Cond = 2041 dyn_cast_or_null<BinaryOperator>(C ? C->IgnoreParens() : 0)) 2042 if (Cond->isLogicalOp()) { 2043 llvm::tie(EntryConditionBlock, ExitConditionBlock) = 2044 VisitLogicalOperator(Cond, F, BodyBlock, LoopSuccessor); 2045 break; 2046 } 2047 2048 // The default case when not handling logical operators. 2049 EntryConditionBlock = ExitConditionBlock = createBlock(false); 2050 ExitConditionBlock->setTerminator(F); 2051 2052 // See if this is a known constant. 2053 TryResult KnownVal(true); 2054 2055 if (C) { 2056 // Now add the actual condition to the condition block. 2057 // Because the condition itself may contain control-flow, new blocks may 2058 // be created. Thus we update "Succ" after adding the condition. 2059 Block = ExitConditionBlock; 2060 EntryConditionBlock = addStmt(C); 2061 2062 // If this block contains a condition variable, add both the condition 2063 // variable and initializer to the CFG. 2064 if (VarDecl *VD = F->getConditionVariable()) { 2065 if (Expr *Init = VD->getInit()) { 2066 autoCreateBlock(); 2067 appendStmt(Block, F->getConditionVariableDeclStmt()); 2068 EntryConditionBlock = addStmt(Init); 2069 assert(Block == EntryConditionBlock); 2070 } 2071 } 2072 2073 if (Block && badCFG) 2074 return 0; 2075 2076 KnownVal = tryEvaluateBool(C); 2077 } 2078 2079 // Add the loop body entry as a successor to the condition. 2080 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2081 // Link up the condition block with the code that follows the loop. (the 2082 // false branch). 2083 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2084 2085 } while (false); 2086 2087 // Link up the loop-back block to the entry condition block. 2088 addSuccessor(TransitionBlock, EntryConditionBlock); 2089 2090 // The condition block is the implicit successor for any code above the loop. 2091 Succ = EntryConditionBlock; 2092 2093 // If the loop contains initialization, create a new block for those 2094 // statements. This block can also contain statements that precede the loop. 2095 if (Stmt *I = F->getInit()) { 2096 Block = createBlock(); 2097 return addStmt(I); 2098 } 2099 2100 // There is no loop initialization. We are thus basically a while loop. 2101 // NULL out Block to force lazy block construction. 2102 Block = NULL; 2103 Succ = EntryConditionBlock; 2104 return EntryConditionBlock; 2105} 2106 2107CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 2108 if (asc.alwaysAdd(*this, M)) { 2109 autoCreateBlock(); 2110 appendStmt(Block, M); 2111 } 2112 return Visit(M->getBase()); 2113} 2114 2115CFGBlock *CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt *S) { 2116 // Objective-C fast enumeration 'for' statements: 2117 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 2118 // 2119 // for ( Type newVariable in collection_expression ) { statements } 2120 // 2121 // becomes: 2122 // 2123 // prologue: 2124 // 1. collection_expression 2125 // T. jump to loop_entry 2126 // loop_entry: 2127 // 1. side-effects of element expression 2128 // 1. ObjCForCollectionStmt [performs binding to newVariable] 2129 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 2130 // TB: 2131 // statements 2132 // T. jump to loop_entry 2133 // FB: 2134 // what comes after 2135 // 2136 // and 2137 // 2138 // Type existingItem; 2139 // for ( existingItem in expression ) { statements } 2140 // 2141 // becomes: 2142 // 2143 // the same with newVariable replaced with existingItem; the binding works 2144 // the same except that for one ObjCForCollectionStmt::getElement() returns 2145 // a DeclStmt and the other returns a DeclRefExpr. 2146 // 2147 2148 CFGBlock *LoopSuccessor = 0; 2149 2150 if (Block) { 2151 if (badCFG) 2152 return 0; 2153 LoopSuccessor = Block; 2154 Block = 0; 2155 } else 2156 LoopSuccessor = Succ; 2157 2158 // Build the condition blocks. 2159 CFGBlock *ExitConditionBlock = createBlock(false); 2160 2161 // Set the terminator for the "exit" condition block. 2162 ExitConditionBlock->setTerminator(S); 2163 2164 // The last statement in the block should be the ObjCForCollectionStmt, which 2165 // performs the actual binding to 'element' and determines if there are any 2166 // more items in the collection. 2167 appendStmt(ExitConditionBlock, S); 2168 Block = ExitConditionBlock; 2169 2170 // Walk the 'element' expression to see if there are any side-effects. We 2171 // generate new blocks as necessary. We DON'T add the statement by default to 2172 // the CFG unless it contains control-flow. 2173 CFGBlock *EntryConditionBlock = Visit(S->getElement(), 2174 AddStmtChoice::NotAlwaysAdd); 2175 if (Block) { 2176 if (badCFG) 2177 return 0; 2178 Block = 0; 2179 } 2180 2181 // The condition block is the implicit successor for the loop body as well as 2182 // any code above the loop. 2183 Succ = EntryConditionBlock; 2184 2185 // Now create the true branch. 2186 { 2187 // Save the current values for Succ, continue and break targets. 2188 SaveAndRestore<CFGBlock*> save_Succ(Succ); 2189 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2190 save_break(BreakJumpTarget); 2191 2192 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2193 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2194 2195 CFGBlock *BodyBlock = addStmt(S->getBody()); 2196 2197 if (!BodyBlock) 2198 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 2199 else if (Block) { 2200 if (badCFG) 2201 return 0; 2202 } 2203 2204 // This new body block is a successor to our "exit" condition block. 2205 addSuccessor(ExitConditionBlock, BodyBlock); 2206 } 2207 2208 // Link up the condition block with the code that follows the loop. 2209 // (the false branch). 2210 addSuccessor(ExitConditionBlock, LoopSuccessor); 2211 2212 // Now create a prologue block to contain the collection expression. 2213 Block = createBlock(); 2214 return addStmt(S->getCollection()); 2215} 2216 2217CFGBlock *CFGBuilder::VisitObjCAutoreleasePoolStmt(ObjCAutoreleasePoolStmt *S) { 2218 // Inline the body. 2219 return addStmt(S->getSubStmt()); 2220 // TODO: consider adding cleanups for the end of @autoreleasepool scope. 2221} 2222 2223CFGBlock *CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S) { 2224 // FIXME: Add locking 'primitives' to CFG for @synchronized. 2225 2226 // Inline the body. 2227 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 2228 2229 // The sync body starts its own basic block. This makes it a little easier 2230 // for diagnostic clients. 2231 if (SyncBlock) { 2232 if (badCFG) 2233 return 0; 2234 2235 Block = 0; 2236 Succ = SyncBlock; 2237 } 2238 2239 // Add the @synchronized to the CFG. 2240 autoCreateBlock(); 2241 appendStmt(Block, S); 2242 2243 // Inline the sync expression. 2244 return addStmt(S->getSynchExpr()); 2245} 2246 2247CFGBlock *CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt *S) { 2248 // FIXME 2249 return NYS(); 2250} 2251 2252CFGBlock *CFGBuilder::VisitPseudoObjectExpr(PseudoObjectExpr *E) { 2253 autoCreateBlock(); 2254 2255 // Add the PseudoObject as the last thing. 2256 appendStmt(Block, E); 2257 2258 CFGBlock *lastBlock = Block; 2259 2260 // Before that, evaluate all of the semantics in order. In 2261 // CFG-land, that means appending them in reverse order. 2262 for (unsigned i = E->getNumSemanticExprs(); i != 0; ) { 2263 Expr *Semantic = E->getSemanticExpr(--i); 2264 2265 // If the semantic is an opaque value, we're being asked to bind 2266 // it to its source expression. 2267 if (OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(Semantic)) 2268 Semantic = OVE->getSourceExpr(); 2269 2270 if (CFGBlock *B = Visit(Semantic)) 2271 lastBlock = B; 2272 } 2273 2274 return lastBlock; 2275} 2276 2277CFGBlock *CFGBuilder::VisitWhileStmt(WhileStmt *W) { 2278 CFGBlock *LoopSuccessor = NULL; 2279 2280 // Save local scope position because in case of condition variable ScopePos 2281 // won't be restored when traversing AST. 2282 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2283 2284 // Create local scope for possible condition variable. 2285 // Store scope position for continue statement. 2286 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 2287 if (VarDecl *VD = W->getConditionVariable()) { 2288 addLocalScopeForVarDecl(VD); 2289 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2290 } 2291 2292 // "while" is a control-flow statement. Thus we stop processing the current 2293 // block. 2294 if (Block) { 2295 if (badCFG) 2296 return 0; 2297 LoopSuccessor = Block; 2298 Block = 0; 2299 } else { 2300 LoopSuccessor = Succ; 2301 } 2302 2303 CFGBlock *BodyBlock = 0, *TransitionBlock = 0; 2304 2305 // Process the loop body. 2306 { 2307 assert(W->getBody()); 2308 2309 // Save the current values for Block, Succ, continue and break targets. 2310 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2311 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2312 save_break(BreakJumpTarget); 2313 2314 // Create an empty block to represent the transition block for looping back 2315 // to the head of the loop. 2316 Succ = TransitionBlock = createBlock(false); 2317 TransitionBlock->setLoopTarget(W); 2318 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 2319 2320 // All breaks should go to the code following the loop. 2321 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2322 2323 // Loop body should end with destructor of Condition variable (if any). 2324 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 2325 2326 // If body is not a compound statement create implicit scope 2327 // and add destructors. 2328 if (!isa<CompoundStmt>(W->getBody())) 2329 addLocalScopeAndDtors(W->getBody()); 2330 2331 // Create the body. The returned block is the entry to the loop body. 2332 BodyBlock = addStmt(W->getBody()); 2333 2334 if (!BodyBlock) 2335 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 2336 else if (Block && badCFG) 2337 return 0; 2338 } 2339 2340 // Because of short-circuit evaluation, the condition of the loop can span 2341 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2342 // evaluate the condition. 2343 CFGBlock *EntryConditionBlock = 0, *ExitConditionBlock = 0; 2344 2345 do { 2346 Expr *C = W->getCond(); 2347 2348 // Specially handle logical operators, which have a slightly 2349 // more optimal CFG representation. 2350 if (BinaryOperator *Cond = dyn_cast<BinaryOperator>(C->IgnoreParens())) 2351 if (Cond->isLogicalOp()) { 2352 llvm::tie(EntryConditionBlock, ExitConditionBlock) = 2353 VisitLogicalOperator(Cond, W, BodyBlock, 2354 LoopSuccessor); 2355 break; 2356 } 2357 2358 // The default case when not handling logical operators. 2359 ExitConditionBlock = createBlock(false); 2360 ExitConditionBlock->setTerminator(W); 2361 2362 // Now add the actual condition to the condition block. 2363 // Because the condition itself may contain control-flow, new blocks may 2364 // be created. Thus we update "Succ" after adding the condition. 2365 Block = ExitConditionBlock; 2366 Block = EntryConditionBlock = addStmt(C); 2367 2368 // If this block contains a condition variable, add both the condition 2369 // variable and initializer to the CFG. 2370 if (VarDecl *VD = W->getConditionVariable()) { 2371 if (Expr *Init = VD->getInit()) { 2372 autoCreateBlock(); 2373 appendStmt(Block, W->getConditionVariableDeclStmt()); 2374 EntryConditionBlock = addStmt(Init); 2375 assert(Block == EntryConditionBlock); 2376 } 2377 } 2378 2379 if (Block && badCFG) 2380 return 0; 2381 2382 // See if this is a known constant. 2383 const TryResult& KnownVal = tryEvaluateBool(C); 2384 2385 // Add the loop body entry as a successor to the condition. 2386 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 2387 // Link up the condition block with the code that follows the loop. (the 2388 // false branch). 2389 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2390 2391 } while(false); 2392 2393 // Link up the loop-back block to the entry condition block. 2394 addSuccessor(TransitionBlock, EntryConditionBlock); 2395 2396 // There can be no more statements in the condition block since we loop back 2397 // to this block. NULL out Block to force lazy creation of another block. 2398 Block = NULL; 2399 2400 // Return the condition block, which is the dominating block for the loop. 2401 Succ = EntryConditionBlock; 2402 return EntryConditionBlock; 2403} 2404 2405 2406CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt *S) { 2407 // FIXME: For now we pretend that @catch and the code it contains does not 2408 // exit. 2409 return Block; 2410} 2411 2412CFGBlock *CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt *S) { 2413 // FIXME: This isn't complete. We basically treat @throw like a return 2414 // statement. 2415 2416 // If we were in the middle of a block we stop processing that block. 2417 if (badCFG) 2418 return 0; 2419 2420 // Create the new block. 2421 Block = createBlock(false); 2422 2423 // The Exit block is the only successor. 2424 addSuccessor(Block, &cfg->getExit()); 2425 2426 // Add the statement to the block. This may create new blocks if S contains 2427 // control-flow (short-circuit operations). 2428 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 2429} 2430 2431CFGBlock *CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr *T) { 2432 // If we were in the middle of a block we stop processing that block. 2433 if (badCFG) 2434 return 0; 2435 2436 // Create the new block. 2437 Block = createBlock(false); 2438 2439 if (TryTerminatedBlock) 2440 // The current try statement is the only successor. 2441 addSuccessor(Block, TryTerminatedBlock); 2442 else 2443 // otherwise the Exit block is the only successor. 2444 addSuccessor(Block, &cfg->getExit()); 2445 2446 // Add the statement to the block. This may create new blocks if S contains 2447 // control-flow (short-circuit operations). 2448 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 2449} 2450 2451CFGBlock *CFGBuilder::VisitDoStmt(DoStmt *D) { 2452 CFGBlock *LoopSuccessor = NULL; 2453 2454 // "do...while" is a control-flow statement. Thus we stop processing the 2455 // current block. 2456 if (Block) { 2457 if (badCFG) 2458 return 0; 2459 LoopSuccessor = Block; 2460 } else 2461 LoopSuccessor = Succ; 2462 2463 // Because of short-circuit evaluation, the condition of the loop can span 2464 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2465 // evaluate the condition. 2466 CFGBlock *ExitConditionBlock = createBlock(false); 2467 CFGBlock *EntryConditionBlock = ExitConditionBlock; 2468 2469 // Set the terminator for the "exit" condition block. 2470 ExitConditionBlock->setTerminator(D); 2471 2472 // Now add the actual condition to the condition block. Because the condition 2473 // itself may contain control-flow, new blocks may be created. 2474 if (Stmt *C = D->getCond()) { 2475 Block = ExitConditionBlock; 2476 EntryConditionBlock = addStmt(C); 2477 if (Block) { 2478 if (badCFG) 2479 return 0; 2480 } 2481 } 2482 2483 // The condition block is the implicit successor for the loop body. 2484 Succ = EntryConditionBlock; 2485 2486 // See if this is a known constant. 2487 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2488 2489 // Process the loop body. 2490 CFGBlock *BodyBlock = NULL; 2491 { 2492 assert(D->getBody()); 2493 2494 // Save the current values for Block, Succ, and continue and break targets 2495 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2496 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2497 save_break(BreakJumpTarget); 2498 2499 // All continues within this loop should go to the condition block 2500 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2501 2502 // All breaks should go to the code following the loop. 2503 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2504 2505 // NULL out Block to force lazy instantiation of blocks for the body. 2506 Block = NULL; 2507 2508 // If body is not a compound statement create implicit scope 2509 // and add destructors. 2510 if (!isa<CompoundStmt>(D->getBody())) 2511 addLocalScopeAndDtors(D->getBody()); 2512 2513 // Create the body. The returned block is the entry to the loop body. 2514 BodyBlock = addStmt(D->getBody()); 2515 2516 if (!BodyBlock) 2517 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2518 else if (Block) { 2519 if (badCFG) 2520 return 0; 2521 } 2522 2523 if (!KnownVal.isFalse()) { 2524 // Add an intermediate block between the BodyBlock and the 2525 // ExitConditionBlock to represent the "loop back" transition. Create an 2526 // empty block to represent the transition block for looping back to the 2527 // head of the loop. 2528 // FIXME: Can we do this more efficiently without adding another block? 2529 Block = NULL; 2530 Succ = BodyBlock; 2531 CFGBlock *LoopBackBlock = createBlock(); 2532 LoopBackBlock->setLoopTarget(D); 2533 2534 // Add the loop body entry as a successor to the condition. 2535 addSuccessor(ExitConditionBlock, LoopBackBlock); 2536 } 2537 else 2538 addSuccessor(ExitConditionBlock, NULL); 2539 } 2540 2541 // Link up the condition block with the code that follows the loop. 2542 // (the false branch). 2543 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2544 2545 // There can be no more statements in the body block(s) since we loop back to 2546 // the body. NULL out Block to force lazy creation of another block. 2547 Block = NULL; 2548 2549 // Return the loop body, which is the dominating block for the loop. 2550 Succ = BodyBlock; 2551 return BodyBlock; 2552} 2553 2554CFGBlock *CFGBuilder::VisitContinueStmt(ContinueStmt *C) { 2555 // "continue" is a control-flow statement. Thus we stop processing the 2556 // current block. 2557 if (badCFG) 2558 return 0; 2559 2560 // Now create a new block that ends with the continue statement. 2561 Block = createBlock(false); 2562 Block->setTerminator(C); 2563 2564 // If there is no target for the continue, then we are looking at an 2565 // incomplete AST. This means the CFG cannot be constructed. 2566 if (ContinueJumpTarget.block) { 2567 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2568 addSuccessor(Block, ContinueJumpTarget.block); 2569 } else 2570 badCFG = true; 2571 2572 return Block; 2573} 2574 2575CFGBlock *CFGBuilder::VisitUnaryExprOrTypeTraitExpr(UnaryExprOrTypeTraitExpr *E, 2576 AddStmtChoice asc) { 2577 2578 if (asc.alwaysAdd(*this, E)) { 2579 autoCreateBlock(); 2580 appendStmt(Block, E); 2581 } 2582 2583 // VLA types have expressions that must be evaluated. 2584 CFGBlock *lastBlock = Block; 2585 2586 if (E->isArgumentType()) { 2587 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2588 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2589 lastBlock = addStmt(VA->getSizeExpr()); 2590 } 2591 return lastBlock; 2592} 2593 2594/// VisitStmtExpr - Utility method to handle (nested) statement 2595/// expressions (a GCC extension). 2596CFGBlock *CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2597 if (asc.alwaysAdd(*this, SE)) { 2598 autoCreateBlock(); 2599 appendStmt(Block, SE); 2600 } 2601 return VisitCompoundStmt(SE->getSubStmt()); 2602} 2603 2604CFGBlock *CFGBuilder::VisitSwitchStmt(SwitchStmt *Terminator) { 2605 // "switch" is a control-flow statement. Thus we stop processing the current 2606 // block. 2607 CFGBlock *SwitchSuccessor = NULL; 2608 2609 // Save local scope position because in case of condition variable ScopePos 2610 // won't be restored when traversing AST. 2611 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2612 2613 // Create local scope for possible condition variable. 2614 // Store scope position. Add implicit destructor. 2615 if (VarDecl *VD = Terminator->getConditionVariable()) { 2616 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2617 addLocalScopeForVarDecl(VD); 2618 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2619 } 2620 2621 if (Block) { 2622 if (badCFG) 2623 return 0; 2624 SwitchSuccessor = Block; 2625 } else SwitchSuccessor = Succ; 2626 2627 // Save the current "switch" context. 2628 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2629 save_default(DefaultCaseBlock); 2630 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2631 2632 // Set the "default" case to be the block after the switch statement. If the 2633 // switch statement contains a "default:", this value will be overwritten with 2634 // the block for that code. 2635 DefaultCaseBlock = SwitchSuccessor; 2636 2637 // Create a new block that will contain the switch statement. 2638 SwitchTerminatedBlock = createBlock(false); 2639 2640 // Now process the switch body. The code after the switch is the implicit 2641 // successor. 2642 Succ = SwitchSuccessor; 2643 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2644 2645 // When visiting the body, the case statements should automatically get linked 2646 // up to the switch. We also don't keep a pointer to the body, since all 2647 // control-flow from the switch goes to case/default statements. 2648 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2649 Block = NULL; 2650 2651 // For pruning unreachable case statements, save the current state 2652 // for tracking the condition value. 2653 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2654 false); 2655 2656 // Determine if the switch condition can be explicitly evaluated. 2657 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2658 Expr::EvalResult result; 2659 bool b = tryEvaluate(Terminator->getCond(), result); 2660 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, 2661 b ? &result : 0); 2662 2663 // If body is not a compound statement create implicit scope 2664 // and add destructors. 2665 if (!isa<CompoundStmt>(Terminator->getBody())) 2666 addLocalScopeAndDtors(Terminator->getBody()); 2667 2668 addStmt(Terminator->getBody()); 2669 if (Block) { 2670 if (badCFG) 2671 return 0; 2672 } 2673 2674 // If we have no "default:" case, the default transition is to the code 2675 // following the switch body. Moreover, take into account if all the 2676 // cases of a switch are covered (e.g., switching on an enum value). 2677 addSuccessor(SwitchTerminatedBlock, 2678 switchExclusivelyCovered || Terminator->isAllEnumCasesCovered() 2679 ? 0 : DefaultCaseBlock); 2680 2681 // Add the terminator and condition in the switch block. 2682 SwitchTerminatedBlock->setTerminator(Terminator); 2683 Block = SwitchTerminatedBlock; 2684 CFGBlock *LastBlock = addStmt(Terminator->getCond()); 2685 2686 // Finally, if the SwitchStmt contains a condition variable, add both the 2687 // SwitchStmt and the condition variable initialization to the CFG. 2688 if (VarDecl *VD = Terminator->getConditionVariable()) { 2689 if (Expr *Init = VD->getInit()) { 2690 autoCreateBlock(); 2691 appendStmt(Block, Terminator->getConditionVariableDeclStmt()); 2692 LastBlock = addStmt(Init); 2693 } 2694 } 2695 2696 return LastBlock; 2697} 2698 2699static bool shouldAddCase(bool &switchExclusivelyCovered, 2700 const Expr::EvalResult *switchCond, 2701 const CaseStmt *CS, 2702 ASTContext &Ctx) { 2703 if (!switchCond) 2704 return true; 2705 2706 bool addCase = false; 2707 2708 if (!switchExclusivelyCovered) { 2709 if (switchCond->Val.isInt()) { 2710 // Evaluate the LHS of the case value. 2711 const llvm::APSInt &lhsInt = CS->getLHS()->EvaluateKnownConstInt(Ctx); 2712 const llvm::APSInt &condInt = switchCond->Val.getInt(); 2713 2714 if (condInt == lhsInt) { 2715 addCase = true; 2716 switchExclusivelyCovered = true; 2717 } 2718 else if (condInt < lhsInt) { 2719 if (const Expr *RHS = CS->getRHS()) { 2720 // Evaluate the RHS of the case value. 2721 const llvm::APSInt &V2 = RHS->EvaluateKnownConstInt(Ctx); 2722 if (V2 <= condInt) { 2723 addCase = true; 2724 switchExclusivelyCovered = true; 2725 } 2726 } 2727 } 2728 } 2729 else 2730 addCase = true; 2731 } 2732 return addCase; 2733} 2734 2735CFGBlock *CFGBuilder::VisitCaseStmt(CaseStmt *CS) { 2736 // CaseStmts are essentially labels, so they are the first statement in a 2737 // block. 2738 CFGBlock *TopBlock = 0, *LastBlock = 0; 2739 2740 if (Stmt *Sub = CS->getSubStmt()) { 2741 // For deeply nested chains of CaseStmts, instead of doing a recursion 2742 // (which can blow out the stack), manually unroll and create blocks 2743 // along the way. 2744 while (isa<CaseStmt>(Sub)) { 2745 CFGBlock *currentBlock = createBlock(false); 2746 currentBlock->setLabel(CS); 2747 2748 if (TopBlock) 2749 addSuccessor(LastBlock, currentBlock); 2750 else 2751 TopBlock = currentBlock; 2752 2753 addSuccessor(SwitchTerminatedBlock, 2754 shouldAddCase(switchExclusivelyCovered, switchCond, 2755 CS, *Context) 2756 ? currentBlock : 0); 2757 2758 LastBlock = currentBlock; 2759 CS = cast<CaseStmt>(Sub); 2760 Sub = CS->getSubStmt(); 2761 } 2762 2763 addStmt(Sub); 2764 } 2765 2766 CFGBlock *CaseBlock = Block; 2767 if (!CaseBlock) 2768 CaseBlock = createBlock(); 2769 2770 // Cases statements partition blocks, so this is the top of the basic block we 2771 // were processing (the "case XXX:" is the label). 2772 CaseBlock->setLabel(CS); 2773 2774 if (badCFG) 2775 return 0; 2776 2777 // Add this block to the list of successors for the block with the switch 2778 // statement. 2779 assert(SwitchTerminatedBlock); 2780 addSuccessor(SwitchTerminatedBlock, 2781 shouldAddCase(switchExclusivelyCovered, switchCond, 2782 CS, *Context) 2783 ? CaseBlock : 0); 2784 2785 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2786 Block = NULL; 2787 2788 if (TopBlock) { 2789 addSuccessor(LastBlock, CaseBlock); 2790 Succ = TopBlock; 2791 } else { 2792 // This block is now the implicit successor of other blocks. 2793 Succ = CaseBlock; 2794 } 2795 2796 return Succ; 2797} 2798 2799CFGBlock *CFGBuilder::VisitDefaultStmt(DefaultStmt *Terminator) { 2800 if (Terminator->getSubStmt()) 2801 addStmt(Terminator->getSubStmt()); 2802 2803 DefaultCaseBlock = Block; 2804 2805 if (!DefaultCaseBlock) 2806 DefaultCaseBlock = createBlock(); 2807 2808 // Default statements partition blocks, so this is the top of the basic block 2809 // we were processing (the "default:" is the label). 2810 DefaultCaseBlock->setLabel(Terminator); 2811 2812 if (badCFG) 2813 return 0; 2814 2815 // Unlike case statements, we don't add the default block to the successors 2816 // for the switch statement immediately. This is done when we finish 2817 // processing the switch statement. This allows for the default case 2818 // (including a fall-through to the code after the switch statement) to always 2819 // be the last successor of a switch-terminated block. 2820 2821 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2822 Block = NULL; 2823 2824 // This block is now the implicit successor of other blocks. 2825 Succ = DefaultCaseBlock; 2826 2827 return DefaultCaseBlock; 2828} 2829 2830CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2831 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2832 // current block. 2833 CFGBlock *TrySuccessor = NULL; 2834 2835 if (Block) { 2836 if (badCFG) 2837 return 0; 2838 TrySuccessor = Block; 2839 } else TrySuccessor = Succ; 2840 2841 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2842 2843 // Create a new block that will contain the try statement. 2844 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2845 // Add the terminator in the try block. 2846 NewTryTerminatedBlock->setTerminator(Terminator); 2847 2848 bool HasCatchAll = false; 2849 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2850 // The code after the try is the implicit successor. 2851 Succ = TrySuccessor; 2852 CXXCatchStmt *CS = Terminator->getHandler(h); 2853 if (CS->getExceptionDecl() == 0) { 2854 HasCatchAll = true; 2855 } 2856 Block = NULL; 2857 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2858 if (CatchBlock == 0) 2859 return 0; 2860 // Add this block to the list of successors for the block with the try 2861 // statement. 2862 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2863 } 2864 if (!HasCatchAll) { 2865 if (PrevTryTerminatedBlock) 2866 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2867 else 2868 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2869 } 2870 2871 // The code after the try is the implicit successor. 2872 Succ = TrySuccessor; 2873 2874 // Save the current "try" context. 2875 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock, NewTryTerminatedBlock); 2876 cfg->addTryDispatchBlock(TryTerminatedBlock); 2877 2878 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2879 Block = NULL; 2880 return addStmt(Terminator->getTryBlock()); 2881} 2882 2883CFGBlock *CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt *CS) { 2884 // CXXCatchStmt are treated like labels, so they are the first statement in a 2885 // block. 2886 2887 // Save local scope position because in case of exception variable ScopePos 2888 // won't be restored when traversing AST. 2889 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2890 2891 // Create local scope for possible exception variable. 2892 // Store scope position. Add implicit destructor. 2893 if (VarDecl *VD = CS->getExceptionDecl()) { 2894 LocalScope::const_iterator BeginScopePos = ScopePos; 2895 addLocalScopeForVarDecl(VD); 2896 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2897 } 2898 2899 if (CS->getHandlerBlock()) 2900 addStmt(CS->getHandlerBlock()); 2901 2902 CFGBlock *CatchBlock = Block; 2903 if (!CatchBlock) 2904 CatchBlock = createBlock(); 2905 2906 // CXXCatchStmt is more than just a label. They have semantic meaning 2907 // as well, as they implicitly "initialize" the catch variable. Add 2908 // it to the CFG as a CFGElement so that the control-flow of these 2909 // semantics gets captured. 2910 appendStmt(CatchBlock, CS); 2911 2912 // Also add the CXXCatchStmt as a label, to mirror handling of regular 2913 // labels. 2914 CatchBlock->setLabel(CS); 2915 2916 // Bail out if the CFG is bad. 2917 if (badCFG) 2918 return 0; 2919 2920 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2921 Block = NULL; 2922 2923 return CatchBlock; 2924} 2925 2926CFGBlock *CFGBuilder::VisitCXXForRangeStmt(CXXForRangeStmt *S) { 2927 // C++0x for-range statements are specified as [stmt.ranged]: 2928 // 2929 // { 2930 // auto && __range = range-init; 2931 // for ( auto __begin = begin-expr, 2932 // __end = end-expr; 2933 // __begin != __end; 2934 // ++__begin ) { 2935 // for-range-declaration = *__begin; 2936 // statement 2937 // } 2938 // } 2939 2940 // Save local scope position before the addition of the implicit variables. 2941 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2942 2943 // Create local scopes and destructors for range, begin and end variables. 2944 if (Stmt *Range = S->getRangeStmt()) 2945 addLocalScopeForStmt(Range); 2946 if (Stmt *BeginEnd = S->getBeginEndStmt()) 2947 addLocalScopeForStmt(BeginEnd); 2948 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), S); 2949 2950 LocalScope::const_iterator ContinueScopePos = ScopePos; 2951 2952 // "for" is a control-flow statement. Thus we stop processing the current 2953 // block. 2954 CFGBlock *LoopSuccessor = NULL; 2955 if (Block) { 2956 if (badCFG) 2957 return 0; 2958 LoopSuccessor = Block; 2959 } else 2960 LoopSuccessor = Succ; 2961 2962 // Save the current value for the break targets. 2963 // All breaks should go to the code following the loop. 2964 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2965 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2966 2967 // The block for the __begin != __end expression. 2968 CFGBlock *ConditionBlock = createBlock(false); 2969 ConditionBlock->setTerminator(S); 2970 2971 // Now add the actual condition to the condition block. 2972 if (Expr *C = S->getCond()) { 2973 Block = ConditionBlock; 2974 CFGBlock *BeginConditionBlock = addStmt(C); 2975 if (badCFG) 2976 return 0; 2977 assert(BeginConditionBlock == ConditionBlock && 2978 "condition block in for-range was unexpectedly complex"); 2979 (void)BeginConditionBlock; 2980 } 2981 2982 // The condition block is the implicit successor for the loop body as well as 2983 // any code above the loop. 2984 Succ = ConditionBlock; 2985 2986 // See if this is a known constant. 2987 TryResult KnownVal(true); 2988 2989 if (S->getCond()) 2990 KnownVal = tryEvaluateBool(S->getCond()); 2991 2992 // Now create the loop body. 2993 { 2994 assert(S->getBody()); 2995 2996 // Save the current values for Block, Succ, and continue targets. 2997 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2998 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 2999 3000 // Generate increment code in its own basic block. This is the target of 3001 // continue statements. 3002 Block = 0; 3003 Succ = addStmt(S->getInc()); 3004 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 3005 3006 // The starting block for the loop increment is the block that should 3007 // represent the 'loop target' for looping back to the start of the loop. 3008 ContinueJumpTarget.block->setLoopTarget(S); 3009 3010 // Finish up the increment block and prepare to start the loop body. 3011 assert(Block); 3012 if (badCFG) 3013 return 0; 3014 Block = 0; 3015 3016 3017 // Add implicit scope and dtors for loop variable. 3018 addLocalScopeAndDtors(S->getLoopVarStmt()); 3019 3020 // Populate a new block to contain the loop body and loop variable. 3021 addStmt(S->getBody()); 3022 if (badCFG) 3023 return 0; 3024 CFGBlock *LoopVarStmtBlock = addStmt(S->getLoopVarStmt()); 3025 if (badCFG) 3026 return 0; 3027 3028 // This new body block is a successor to our condition block. 3029 addSuccessor(ConditionBlock, KnownVal.isFalse() ? 0 : LoopVarStmtBlock); 3030 } 3031 3032 // Link up the condition block with the code that follows the loop (the 3033 // false branch). 3034 addSuccessor(ConditionBlock, KnownVal.isTrue() ? 0 : LoopSuccessor); 3035 3036 // Add the initialization statements. 3037 Block = createBlock(); 3038 addStmt(S->getBeginEndStmt()); 3039 return addStmt(S->getRangeStmt()); 3040} 3041 3042CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 3043 AddStmtChoice asc) { 3044 if (BuildOpts.AddTemporaryDtors) { 3045 // If adding implicit destructors visit the full expression for adding 3046 // destructors of temporaries. 3047 VisitForTemporaryDtors(E->getSubExpr()); 3048 3049 // Full expression has to be added as CFGStmt so it will be sequenced 3050 // before destructors of it's temporaries. 3051 asc = asc.withAlwaysAdd(true); 3052 } 3053 return Visit(E->getSubExpr(), asc); 3054} 3055 3056CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 3057 AddStmtChoice asc) { 3058 if (asc.alwaysAdd(*this, E)) { 3059 autoCreateBlock(); 3060 appendStmt(Block, E); 3061 3062 // We do not want to propagate the AlwaysAdd property. 3063 asc = asc.withAlwaysAdd(false); 3064 } 3065 return Visit(E->getSubExpr(), asc); 3066} 3067 3068CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 3069 AddStmtChoice asc) { 3070 autoCreateBlock(); 3071 appendStmt(Block, C); 3072 3073 return VisitChildren(C); 3074} 3075 3076CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 3077 AddStmtChoice asc) { 3078 if (asc.alwaysAdd(*this, E)) { 3079 autoCreateBlock(); 3080 appendStmt(Block, E); 3081 // We do not want to propagate the AlwaysAdd property. 3082 asc = asc.withAlwaysAdd(false); 3083 } 3084 return Visit(E->getSubExpr(), asc); 3085} 3086 3087CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 3088 AddStmtChoice asc) { 3089 autoCreateBlock(); 3090 appendStmt(Block, C); 3091 return VisitChildren(C); 3092} 3093 3094CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 3095 AddStmtChoice asc) { 3096 if (asc.alwaysAdd(*this, E)) { 3097 autoCreateBlock(); 3098 appendStmt(Block, E); 3099 } 3100 return Visit(E->getSubExpr(), AddStmtChoice()); 3101} 3102 3103CFGBlock *CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3104 // Lazily create the indirect-goto dispatch block if there isn't one already. 3105 CFGBlock *IBlock = cfg->getIndirectGotoBlock(); 3106 3107 if (!IBlock) { 3108 IBlock = createBlock(false); 3109 cfg->setIndirectGotoBlock(IBlock); 3110 } 3111 3112 // IndirectGoto is a control-flow statement. Thus we stop processing the 3113 // current block and create a new one. 3114 if (badCFG) 3115 return 0; 3116 3117 Block = createBlock(false); 3118 Block->setTerminator(I); 3119 addSuccessor(Block, IBlock); 3120 return addStmt(I->getTarget()); 3121} 3122 3123CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 3124 assert(BuildOpts.AddImplicitDtors && BuildOpts.AddTemporaryDtors); 3125 3126tryAgain: 3127 if (!E) { 3128 badCFG = true; 3129 return NULL; 3130 } 3131 switch (E->getStmtClass()) { 3132 default: 3133 return VisitChildrenForTemporaryDtors(E); 3134 3135 case Stmt::BinaryOperatorClass: 3136 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 3137 3138 case Stmt::CXXBindTemporaryExprClass: 3139 return VisitCXXBindTemporaryExprForTemporaryDtors( 3140 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 3141 3142 case Stmt::BinaryConditionalOperatorClass: 3143 case Stmt::ConditionalOperatorClass: 3144 return VisitConditionalOperatorForTemporaryDtors( 3145 cast<AbstractConditionalOperator>(E), BindToTemporary); 3146 3147 case Stmt::ImplicitCastExprClass: 3148 // For implicit cast we want BindToTemporary to be passed further. 3149 E = cast<CastExpr>(E)->getSubExpr(); 3150 goto tryAgain; 3151 3152 case Stmt::ParenExprClass: 3153 E = cast<ParenExpr>(E)->getSubExpr(); 3154 goto tryAgain; 3155 3156 case Stmt::MaterializeTemporaryExprClass: 3157 E = cast<MaterializeTemporaryExpr>(E)->GetTemporaryExpr(); 3158 goto tryAgain; 3159 } 3160} 3161 3162CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 3163 // When visiting children for destructors we want to visit them in reverse 3164 // order that they will appear in the CFG. Because the CFG is built 3165 // bottom-up, this means we visit them in their natural order, which 3166 // reverses them in the CFG. 3167 CFGBlock *B = Block; 3168 for (Stmt::child_range I = E->children(); I; ++I) { 3169 if (Stmt *Child = *I) 3170 if (CFGBlock *R = VisitForTemporaryDtors(Child)) 3171 B = R; 3172 } 3173 return B; 3174} 3175 3176CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 3177 if (E->isLogicalOp()) { 3178 // Destructors for temporaries in LHS expression should be called after 3179 // those for RHS expression. Even if this will unnecessarily create a block, 3180 // this block will be used at least by the full expression. 3181 autoCreateBlock(); 3182 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 3183 if (badCFG) 3184 return NULL; 3185 3186 Succ = ConfluenceBlock; 3187 Block = NULL; 3188 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3189 3190 if (RHSBlock) { 3191 if (badCFG) 3192 return NULL; 3193 3194 // If RHS expression did produce destructors we need to connect created 3195 // blocks to CFG in same manner as for binary operator itself. 3196 CFGBlock *LHSBlock = createBlock(false); 3197 LHSBlock->setTerminator(CFGTerminator(E, true)); 3198 3199 // For binary operator LHS block is before RHS in list of predecessors 3200 // of ConfluenceBlock. 3201 std::reverse(ConfluenceBlock->pred_begin(), 3202 ConfluenceBlock->pred_end()); 3203 3204 // See if this is a known constant. 3205 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 3206 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 3207 KnownVal.negate(); 3208 3209 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 3210 // itself. 3211 if (E->getOpcode() == BO_LOr) { 3212 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3213 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3214 } else { 3215 assert (E->getOpcode() == BO_LAnd); 3216 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 3217 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 3218 } 3219 3220 Block = LHSBlock; 3221 return LHSBlock; 3222 } 3223 3224 Block = ConfluenceBlock; 3225 return ConfluenceBlock; 3226 } 3227 3228 if (E->isAssignmentOp()) { 3229 // For assignment operator (=) LHS expression is visited 3230 // before RHS expression. For destructors visit them in reverse order. 3231 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3232 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3233 return LHSBlock ? LHSBlock : RHSBlock; 3234 } 3235 3236 // For any other binary operator RHS expression is visited before 3237 // LHS expression (order of children). For destructors visit them in reverse 3238 // order. 3239 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 3240 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 3241 return RHSBlock ? RHSBlock : LHSBlock; 3242} 3243 3244CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 3245 CXXBindTemporaryExpr *E, bool BindToTemporary) { 3246 // First add destructors for temporaries in subexpression. 3247 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 3248 if (!BindToTemporary) { 3249 // If lifetime of temporary is not prolonged (by assigning to constant 3250 // reference) add destructor for it. 3251 3252 // If the destructor is marked as a no-return destructor, we need to create 3253 // a new block for the destructor which does not have as a successor 3254 // anything built thus far. Control won't flow out of this block. 3255 const CXXDestructorDecl *Dtor = E->getTemporary()->getDestructor(); 3256 if (Dtor->isNoReturn()) 3257 Block = createNoReturnBlock(); 3258 else 3259 autoCreateBlock(); 3260 3261 appendTemporaryDtor(Block, E); 3262 B = Block; 3263 } 3264 return B; 3265} 3266 3267CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 3268 AbstractConditionalOperator *E, bool BindToTemporary) { 3269 // First add destructors for condition expression. Even if this will 3270 // unnecessarily create a block, this block will be used at least by the full 3271 // expression. 3272 autoCreateBlock(); 3273 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 3274 if (badCFG) 3275 return NULL; 3276 if (BinaryConditionalOperator *BCO 3277 = dyn_cast<BinaryConditionalOperator>(E)) { 3278 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 3279 if (badCFG) 3280 return NULL; 3281 } 3282 3283 // Try to add block with destructors for LHS expression. 3284 CFGBlock *LHSBlock = NULL; 3285 Succ = ConfluenceBlock; 3286 Block = NULL; 3287 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 3288 if (badCFG) 3289 return NULL; 3290 3291 // Try to add block with destructors for RHS expression; 3292 Succ = ConfluenceBlock; 3293 Block = NULL; 3294 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 3295 BindToTemporary); 3296 if (badCFG) 3297 return NULL; 3298 3299 if (!RHSBlock && !LHSBlock) { 3300 // If neither LHS nor RHS expression had temporaries to destroy don't create 3301 // more blocks. 3302 Block = ConfluenceBlock; 3303 return Block; 3304 } 3305 3306 Block = createBlock(false); 3307 Block->setTerminator(CFGTerminator(E, true)); 3308 3309 // See if this is a known constant. 3310 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 3311 3312 if (LHSBlock) { 3313 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 3314 } else if (KnownVal.isFalse()) { 3315 addSuccessor(Block, NULL); 3316 } else { 3317 addSuccessor(Block, ConfluenceBlock); 3318 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 3319 } 3320 3321 if (!RHSBlock) 3322 RHSBlock = ConfluenceBlock; 3323 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 3324 3325 return Block; 3326} 3327 3328} // end anonymous namespace 3329 3330/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 3331/// no successors or predecessors. If this is the first block created in the 3332/// CFG, it is automatically set to be the Entry and Exit of the CFG. 3333CFGBlock *CFG::createBlock() { 3334 bool first_block = begin() == end(); 3335 3336 // Create the block. 3337 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 3338 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC, this); 3339 Blocks.push_back(Mem, BlkBVC); 3340 3341 // If this is the first block, set it as the Entry and Exit. 3342 if (first_block) 3343 Entry = Exit = &back(); 3344 3345 // Return the block. 3346 return &back(); 3347} 3348 3349/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 3350/// CFG is returned to the caller. 3351CFG* CFG::buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, 3352 const BuildOptions &BO) { 3353 CFGBuilder Builder(C, BO); 3354 return Builder.buildCFG(D, Statement); 3355} 3356 3357const CXXDestructorDecl * 3358CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 3359 switch (getKind()) { 3360 case CFGElement::Statement: 3361 case CFGElement::Initializer: 3362 llvm_unreachable("getDestructorDecl should only be used with " 3363 "ImplicitDtors"); 3364 case CFGElement::AutomaticObjectDtor: { 3365 const VarDecl *var = castAs<CFGAutomaticObjDtor>().getVarDecl(); 3366 QualType ty = var->getType(); 3367 ty = ty.getNonReferenceType(); 3368 while (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 3369 ty = arrayType->getElementType(); 3370 } 3371 const RecordType *recordType = ty->getAs<RecordType>(); 3372 const CXXRecordDecl *classDecl = 3373 cast<CXXRecordDecl>(recordType->getDecl()); 3374 return classDecl->getDestructor(); 3375 } 3376 case CFGElement::TemporaryDtor: { 3377 const CXXBindTemporaryExpr *bindExpr = 3378 castAs<CFGTemporaryDtor>().getBindTemporaryExpr(); 3379 const CXXTemporary *temp = bindExpr->getTemporary(); 3380 return temp->getDestructor(); 3381 } 3382 case CFGElement::BaseDtor: 3383 case CFGElement::MemberDtor: 3384 3385 // Not yet supported. 3386 return 0; 3387 } 3388 llvm_unreachable("getKind() returned bogus value"); 3389} 3390 3391bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 3392 if (const CXXDestructorDecl *DD = getDestructorDecl(astContext)) 3393 return DD->isNoReturn(); 3394 return false; 3395} 3396 3397//===----------------------------------------------------------------------===// 3398// CFG: Queries for BlkExprs. 3399//===----------------------------------------------------------------------===// 3400 3401namespace { 3402 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 3403} 3404 3405static void FindSubExprAssignments(const Stmt *S, 3406 llvm::SmallPtrSet<const Expr*,50>& Set) { 3407 if (!S) 3408 return; 3409 3410 for (Stmt::const_child_range I = S->children(); I; ++I) { 3411 const Stmt *child = *I; 3412 if (!child) 3413 continue; 3414 3415 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 3416 if (B->isAssignmentOp()) Set.insert(B); 3417 3418 FindSubExprAssignments(child, Set); 3419 } 3420} 3421 3422static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 3423 BlkExprMapTy* M = new BlkExprMapTy(); 3424 3425 // Look for assignments that are used as subexpressions. These are the only 3426 // assignments that we want to *possibly* register as a block-level 3427 // expression. Basically, if an assignment occurs both in a subexpression and 3428 // at the block-level, it is a block-level expression. 3429 llvm::SmallPtrSet<const Expr*,50> SubExprAssignments; 3430 3431 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 3432 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 3433 if (Optional<CFGStmt> S = BI->getAs<CFGStmt>()) 3434 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 3435 3436 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 3437 3438 // Iterate over the statements again on identify the Expr* and Stmt* at the 3439 // block-level that are block-level expressions. 3440 3441 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 3442 Optional<CFGStmt> CS = BI->getAs<CFGStmt>(); 3443 if (!CS) 3444 continue; 3445 if (const Expr *Exp = dyn_cast<Expr>(CS->getStmt())) { 3446 assert((Exp->IgnoreParens() == Exp) && "No parens on block-level exps"); 3447 3448 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 3449 // Assignment expressions that are not nested within another 3450 // expression are really "statements" whose value is never used by 3451 // another expression. 3452 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 3453 continue; 3454 } else if (const StmtExpr *SE = dyn_cast<StmtExpr>(Exp)) { 3455 // Special handling for statement expressions. The last statement in 3456 // the statement expression is also a block-level expr. 3457 const CompoundStmt *C = SE->getSubStmt(); 3458 if (!C->body_empty()) { 3459 const Stmt *Last = C->body_back(); 3460 if (const Expr *LastEx = dyn_cast<Expr>(Last)) 3461 Last = LastEx->IgnoreParens(); 3462 unsigned x = M->size(); 3463 (*M)[Last] = x; 3464 } 3465 } 3466 3467 unsigned x = M->size(); 3468 (*M)[Exp] = x; 3469 } 3470 } 3471 3472 // Look at terminators. The condition is a block-level expression. 3473 3474 Stmt *S = (*I)->getTerminatorCondition(); 3475 3476 if (S && M->find(S) == M->end()) { 3477 unsigned x = M->size(); 3478 (*M)[S] = x; 3479 } 3480 } 3481 3482 return M; 3483} 3484 3485CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt *S) { 3486 assert(S != NULL); 3487 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 3488 3489 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 3490 BlkExprMapTy::iterator I = M->find(S); 3491 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 3492} 3493 3494unsigned CFG::getNumBlkExprs() { 3495 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 3496 return M->size(); 3497 3498 // We assume callers interested in the number of BlkExprs will want 3499 // the map constructed if it doesn't already exist. 3500 BlkExprMap = (void*) PopulateBlkExprMap(*this); 3501 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 3502} 3503 3504//===----------------------------------------------------------------------===// 3505// Filtered walking of the CFG. 3506//===----------------------------------------------------------------------===// 3507 3508bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 3509 const CFGBlock *From, const CFGBlock *To) { 3510 3511 if (To && F.IgnoreDefaultsWithCoveredEnums) { 3512 // If the 'To' has no label or is labeled but the label isn't a 3513 // CaseStmt then filter this edge. 3514 if (const SwitchStmt *S = 3515 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 3516 if (S->isAllEnumCasesCovered()) { 3517 const Stmt *L = To->getLabel(); 3518 if (!L || !isa<CaseStmt>(L)) 3519 return true; 3520 } 3521 } 3522 } 3523 3524 return false; 3525} 3526 3527//===----------------------------------------------------------------------===// 3528// Cleanup: CFG dstor. 3529//===----------------------------------------------------------------------===// 3530 3531CFG::~CFG() { 3532 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 3533} 3534 3535//===----------------------------------------------------------------------===// 3536// CFG pretty printing 3537//===----------------------------------------------------------------------===// 3538 3539namespace { 3540 3541class StmtPrinterHelper : public PrinterHelper { 3542 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 3543 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 3544 StmtMapTy StmtMap; 3545 DeclMapTy DeclMap; 3546 signed currentBlock; 3547 unsigned currStmt; 3548 const LangOptions &LangOpts; 3549public: 3550 3551 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 3552 : currentBlock(0), currStmt(0), LangOpts(LO) 3553 { 3554 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 3555 unsigned j = 1; 3556 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 3557 BI != BEnd; ++BI, ++j ) { 3558 if (Optional<CFGStmt> SE = BI->getAs<CFGStmt>()) { 3559 const Stmt *stmt= SE->getStmt(); 3560 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 3561 StmtMap[stmt] = P; 3562 3563 switch (stmt->getStmtClass()) { 3564 case Stmt::DeclStmtClass: 3565 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 3566 break; 3567 case Stmt::IfStmtClass: { 3568 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 3569 if (var) 3570 DeclMap[var] = P; 3571 break; 3572 } 3573 case Stmt::ForStmtClass: { 3574 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 3575 if (var) 3576 DeclMap[var] = P; 3577 break; 3578 } 3579 case Stmt::WhileStmtClass: { 3580 const VarDecl *var = 3581 cast<WhileStmt>(stmt)->getConditionVariable(); 3582 if (var) 3583 DeclMap[var] = P; 3584 break; 3585 } 3586 case Stmt::SwitchStmtClass: { 3587 const VarDecl *var = 3588 cast<SwitchStmt>(stmt)->getConditionVariable(); 3589 if (var) 3590 DeclMap[var] = P; 3591 break; 3592 } 3593 case Stmt::CXXCatchStmtClass: { 3594 const VarDecl *var = 3595 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3596 if (var) 3597 DeclMap[var] = P; 3598 break; 3599 } 3600 default: 3601 break; 3602 } 3603 } 3604 } 3605 } 3606 } 3607 3608 3609 virtual ~StmtPrinterHelper() {} 3610 3611 const LangOptions &getLangOpts() const { return LangOpts; } 3612 void setBlockID(signed i) { currentBlock = i; } 3613 void setStmtID(unsigned i) { currStmt = i; } 3614 3615 virtual bool handledStmt(Stmt *S, raw_ostream &OS) { 3616 StmtMapTy::iterator I = StmtMap.find(S); 3617 3618 if (I == StmtMap.end()) 3619 return false; 3620 3621 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3622 && I->second.second == currStmt) { 3623 return false; 3624 } 3625 3626 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3627 return true; 3628 } 3629 3630 bool handleDecl(const Decl *D, raw_ostream &OS) { 3631 DeclMapTy::iterator I = DeclMap.find(D); 3632 3633 if (I == DeclMap.end()) 3634 return false; 3635 3636 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3637 && I->second.second == currStmt) { 3638 return false; 3639 } 3640 3641 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3642 return true; 3643 } 3644}; 3645} // end anonymous namespace 3646 3647 3648namespace { 3649class CFGBlockTerminatorPrint 3650 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3651 3652 raw_ostream &OS; 3653 StmtPrinterHelper* Helper; 3654 PrintingPolicy Policy; 3655public: 3656 CFGBlockTerminatorPrint(raw_ostream &os, StmtPrinterHelper* helper, 3657 const PrintingPolicy &Policy) 3658 : OS(os), Helper(helper), Policy(Policy) {} 3659 3660 void VisitIfStmt(IfStmt *I) { 3661 OS << "if "; 3662 I->getCond()->printPretty(OS,Helper,Policy); 3663 } 3664 3665 // Default case. 3666 void VisitStmt(Stmt *Terminator) { 3667 Terminator->printPretty(OS, Helper, Policy); 3668 } 3669 3670 void VisitDeclStmt(DeclStmt *DS) { 3671 VarDecl *VD = cast<VarDecl>(DS->getSingleDecl()); 3672 OS << "static init " << VD->getName(); 3673 } 3674 3675 void VisitForStmt(ForStmt *F) { 3676 OS << "for (" ; 3677 if (F->getInit()) 3678 OS << "..."; 3679 OS << "; "; 3680 if (Stmt *C = F->getCond()) 3681 C->printPretty(OS, Helper, Policy); 3682 OS << "; "; 3683 if (F->getInc()) 3684 OS << "..."; 3685 OS << ")"; 3686 } 3687 3688 void VisitWhileStmt(WhileStmt *W) { 3689 OS << "while " ; 3690 if (Stmt *C = W->getCond()) 3691 C->printPretty(OS, Helper, Policy); 3692 } 3693 3694 void VisitDoStmt(DoStmt *D) { 3695 OS << "do ... while "; 3696 if (Stmt *C = D->getCond()) 3697 C->printPretty(OS, Helper, Policy); 3698 } 3699 3700 void VisitSwitchStmt(SwitchStmt *Terminator) { 3701 OS << "switch "; 3702 Terminator->getCond()->printPretty(OS, Helper, Policy); 3703 } 3704 3705 void VisitCXXTryStmt(CXXTryStmt *CS) { 3706 OS << "try ..."; 3707 } 3708 3709 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3710 C->getCond()->printPretty(OS, Helper, Policy); 3711 OS << " ? ... : ..."; 3712 } 3713 3714 void VisitChooseExpr(ChooseExpr *C) { 3715 OS << "__builtin_choose_expr( "; 3716 C->getCond()->printPretty(OS, Helper, Policy); 3717 OS << " )"; 3718 } 3719 3720 void VisitIndirectGotoStmt(IndirectGotoStmt *I) { 3721 OS << "goto *"; 3722 I->getTarget()->printPretty(OS, Helper, Policy); 3723 } 3724 3725 void VisitBinaryOperator(BinaryOperator* B) { 3726 if (!B->isLogicalOp()) { 3727 VisitExpr(B); 3728 return; 3729 } 3730 3731 B->getLHS()->printPretty(OS, Helper, Policy); 3732 3733 switch (B->getOpcode()) { 3734 case BO_LOr: 3735 OS << " || ..."; 3736 return; 3737 case BO_LAnd: 3738 OS << " && ..."; 3739 return; 3740 default: 3741 llvm_unreachable("Invalid logical operator."); 3742 } 3743 } 3744 3745 void VisitExpr(Expr *E) { 3746 E->printPretty(OS, Helper, Policy); 3747 } 3748}; 3749} // end anonymous namespace 3750 3751static void print_elem(raw_ostream &OS, StmtPrinterHelper* Helper, 3752 const CFGElement &E) { 3753 if (Optional<CFGStmt> CS = E.getAs<CFGStmt>()) { 3754 const Stmt *S = CS->getStmt(); 3755 3756 if (Helper) { 3757 3758 // special printing for statement-expressions. 3759 if (const StmtExpr *SE = dyn_cast<StmtExpr>(S)) { 3760 const CompoundStmt *Sub = SE->getSubStmt(); 3761 3762 if (Sub->children()) { 3763 OS << "({ ... ; "; 3764 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3765 OS << " })\n"; 3766 return; 3767 } 3768 } 3769 // special printing for comma expressions. 3770 if (const BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3771 if (B->getOpcode() == BO_Comma) { 3772 OS << "... , "; 3773 Helper->handledStmt(B->getRHS(),OS); 3774 OS << '\n'; 3775 return; 3776 } 3777 } 3778 } 3779 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3780 3781 if (isa<CXXOperatorCallExpr>(S)) { 3782 OS << " (OperatorCall)"; 3783 } 3784 else if (isa<CXXBindTemporaryExpr>(S)) { 3785 OS << " (BindTemporary)"; 3786 } 3787 else if (const CXXConstructExpr *CCE = dyn_cast<CXXConstructExpr>(S)) { 3788 OS << " (CXXConstructExpr, " << CCE->getType().getAsString() << ")"; 3789 } 3790 else if (const CastExpr *CE = dyn_cast<CastExpr>(S)) { 3791 OS << " (" << CE->getStmtClassName() << ", " 3792 << CE->getCastKindName() 3793 << ", " << CE->getType().getAsString() 3794 << ")"; 3795 } 3796 3797 // Expressions need a newline. 3798 if (isa<Expr>(S)) 3799 OS << '\n'; 3800 3801 } else if (Optional<CFGInitializer> IE = E.getAs<CFGInitializer>()) { 3802 const CXXCtorInitializer *I = IE->getInitializer(); 3803 if (I->isBaseInitializer()) 3804 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3805 else OS << I->getAnyMember()->getName(); 3806 3807 OS << "("; 3808 if (Expr *IE = I->getInit()) 3809 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3810 OS << ")"; 3811 3812 if (I->isBaseInitializer()) 3813 OS << " (Base initializer)\n"; 3814 else OS << " (Member initializer)\n"; 3815 3816 } else if (Optional<CFGAutomaticObjDtor> DE = 3817 E.getAs<CFGAutomaticObjDtor>()) { 3818 const VarDecl *VD = DE->getVarDecl(); 3819 Helper->handleDecl(VD, OS); 3820 3821 const Type* T = VD->getType().getTypePtr(); 3822 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3823 T = RT->getPointeeType().getTypePtr(); 3824 T = T->getBaseElementTypeUnsafe(); 3825 3826 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3827 OS << " (Implicit destructor)\n"; 3828 3829 } else if (Optional<CFGBaseDtor> BE = E.getAs<CFGBaseDtor>()) { 3830 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3831 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3832 OS << " (Base object destructor)\n"; 3833 3834 } else if (Optional<CFGMemberDtor> ME = E.getAs<CFGMemberDtor>()) { 3835 const FieldDecl *FD = ME->getFieldDecl(); 3836 const Type *T = FD->getType()->getBaseElementTypeUnsafe(); 3837 OS << "this->" << FD->getName(); 3838 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3839 OS << " (Member object destructor)\n"; 3840 3841 } else if (Optional<CFGTemporaryDtor> TE = E.getAs<CFGTemporaryDtor>()) { 3842 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3843 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3844 OS << " (Temporary object destructor)\n"; 3845 } 3846} 3847 3848static void print_block(raw_ostream &OS, const CFG* cfg, 3849 const CFGBlock &B, 3850 StmtPrinterHelper* Helper, bool print_edges, 3851 bool ShowColors) { 3852 3853 if (Helper) 3854 Helper->setBlockID(B.getBlockID()); 3855 3856 // Print the header. 3857 if (ShowColors) 3858 OS.changeColor(raw_ostream::YELLOW, true); 3859 3860 OS << "\n [B" << B.getBlockID(); 3861 3862 if (&B == &cfg->getEntry()) 3863 OS << " (ENTRY)]\n"; 3864 else if (&B == &cfg->getExit()) 3865 OS << " (EXIT)]\n"; 3866 else if (&B == cfg->getIndirectGotoBlock()) 3867 OS << " (INDIRECT GOTO DISPATCH)]\n"; 3868 else 3869 OS << "]\n"; 3870 3871 if (ShowColors) 3872 OS.resetColor(); 3873 3874 // Print the label of this block. 3875 if (Stmt *Label = const_cast<Stmt*>(B.getLabel())) { 3876 3877 if (print_edges) 3878 OS << " "; 3879 3880 if (LabelStmt *L = dyn_cast<LabelStmt>(Label)) 3881 OS << L->getName(); 3882 else if (CaseStmt *C = dyn_cast<CaseStmt>(Label)) { 3883 OS << "case "; 3884 C->getLHS()->printPretty(OS, Helper, 3885 PrintingPolicy(Helper->getLangOpts())); 3886 if (C->getRHS()) { 3887 OS << " ... "; 3888 C->getRHS()->printPretty(OS, Helper, 3889 PrintingPolicy(Helper->getLangOpts())); 3890 } 3891 } else if (isa<DefaultStmt>(Label)) 3892 OS << "default"; 3893 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3894 OS << "catch ("; 3895 if (CS->getExceptionDecl()) 3896 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3897 0); 3898 else 3899 OS << "..."; 3900 OS << ")"; 3901 3902 } else 3903 llvm_unreachable("Invalid label statement in CFGBlock."); 3904 3905 OS << ":\n"; 3906 } 3907 3908 // Iterate through the statements in the block and print them. 3909 unsigned j = 1; 3910 3911 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3912 I != E ; ++I, ++j ) { 3913 3914 // Print the statement # in the basic block and the statement itself. 3915 if (print_edges) 3916 OS << " "; 3917 3918 OS << llvm::format("%3d", j) << ": "; 3919 3920 if (Helper) 3921 Helper->setStmtID(j); 3922 3923 print_elem(OS, Helper, *I); 3924 } 3925 3926 // Print the terminator of this block. 3927 if (B.getTerminator()) { 3928 if (ShowColors) 3929 OS.changeColor(raw_ostream::GREEN); 3930 3931 OS << " T: "; 3932 3933 if (Helper) Helper->setBlockID(-1); 3934 3935 PrintingPolicy PP(Helper ? Helper->getLangOpts() : LangOptions()); 3936 CFGBlockTerminatorPrint TPrinter(OS, Helper, PP); 3937 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3938 OS << '\n'; 3939 3940 if (ShowColors) 3941 OS.resetColor(); 3942 } 3943 3944 if (print_edges) { 3945 // Print the predecessors of this block. 3946 if (!B.pred_empty()) { 3947 const raw_ostream::Colors Color = raw_ostream::BLUE; 3948 if (ShowColors) 3949 OS.changeColor(Color); 3950 OS << " Preds " ; 3951 if (ShowColors) 3952 OS.resetColor(); 3953 OS << '(' << B.pred_size() << "):"; 3954 unsigned i = 0; 3955 3956 if (ShowColors) 3957 OS.changeColor(Color); 3958 3959 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3960 I != E; ++I, ++i) { 3961 3962 if (i % 10 == 8) 3963 OS << "\n "; 3964 3965 OS << " B" << (*I)->getBlockID(); 3966 } 3967 3968 if (ShowColors) 3969 OS.resetColor(); 3970 3971 OS << '\n'; 3972 } 3973 3974 // Print the successors of this block. 3975 if (!B.succ_empty()) { 3976 const raw_ostream::Colors Color = raw_ostream::MAGENTA; 3977 if (ShowColors) 3978 OS.changeColor(Color); 3979 OS << " Succs "; 3980 if (ShowColors) 3981 OS.resetColor(); 3982 OS << '(' << B.succ_size() << "):"; 3983 unsigned i = 0; 3984 3985 if (ShowColors) 3986 OS.changeColor(Color); 3987 3988 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3989 I != E; ++I, ++i) { 3990 3991 if (i % 10 == 8) 3992 OS << "\n "; 3993 3994 if (*I) 3995 OS << " B" << (*I)->getBlockID(); 3996 else 3997 OS << " NULL"; 3998 } 3999 4000 if (ShowColors) 4001 OS.resetColor(); 4002 OS << '\n'; 4003 } 4004 } 4005} 4006 4007 4008/// dump - A simple pretty printer of a CFG that outputs to stderr. 4009void CFG::dump(const LangOptions &LO, bool ShowColors) const { 4010 print(llvm::errs(), LO, ShowColors); 4011} 4012 4013/// print - A simple pretty printer of a CFG that outputs to an ostream. 4014void CFG::print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const { 4015 StmtPrinterHelper Helper(this, LO); 4016 4017 // Print the entry block. 4018 print_block(OS, this, getEntry(), &Helper, true, ShowColors); 4019 4020 // Iterate through the CFGBlocks and print them one by one. 4021 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 4022 // Skip the entry block, because we already printed it. 4023 if (&(**I) == &getEntry() || &(**I) == &getExit()) 4024 continue; 4025 4026 print_block(OS, this, **I, &Helper, true, ShowColors); 4027 } 4028 4029 // Print the exit block. 4030 print_block(OS, this, getExit(), &Helper, true, ShowColors); 4031 OS << '\n'; 4032 OS.flush(); 4033} 4034 4035/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 4036void CFGBlock::dump(const CFG* cfg, const LangOptions &LO, 4037 bool ShowColors) const { 4038 print(llvm::errs(), cfg, LO, ShowColors); 4039} 4040 4041/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 4042/// Generally this will only be called from CFG::print. 4043void CFGBlock::print(raw_ostream &OS, const CFG* cfg, 4044 const LangOptions &LO, bool ShowColors) const { 4045 StmtPrinterHelper Helper(cfg, LO); 4046 print_block(OS, cfg, *this, &Helper, true, ShowColors); 4047 OS << '\n'; 4048} 4049 4050/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 4051void CFGBlock::printTerminator(raw_ostream &OS, 4052 const LangOptions &LO) const { 4053 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 4054 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 4055} 4056 4057Stmt *CFGBlock::getTerminatorCondition() { 4058 Stmt *Terminator = this->Terminator; 4059 if (!Terminator) 4060 return NULL; 4061 4062 Expr *E = NULL; 4063 4064 switch (Terminator->getStmtClass()) { 4065 default: 4066 break; 4067 4068 case Stmt::ForStmtClass: 4069 E = cast<ForStmt>(Terminator)->getCond(); 4070 break; 4071 4072 case Stmt::WhileStmtClass: 4073 E = cast<WhileStmt>(Terminator)->getCond(); 4074 break; 4075 4076 case Stmt::DoStmtClass: 4077 E = cast<DoStmt>(Terminator)->getCond(); 4078 break; 4079 4080 case Stmt::IfStmtClass: 4081 E = cast<IfStmt>(Terminator)->getCond(); 4082 break; 4083 4084 case Stmt::ChooseExprClass: 4085 E = cast<ChooseExpr>(Terminator)->getCond(); 4086 break; 4087 4088 case Stmt::IndirectGotoStmtClass: 4089 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 4090 break; 4091 4092 case Stmt::SwitchStmtClass: 4093 E = cast<SwitchStmt>(Terminator)->getCond(); 4094 break; 4095 4096 case Stmt::BinaryConditionalOperatorClass: 4097 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 4098 break; 4099 4100 case Stmt::ConditionalOperatorClass: 4101 E = cast<ConditionalOperator>(Terminator)->getCond(); 4102 break; 4103 4104 case Stmt::BinaryOperatorClass: // '&&' and '||' 4105 E = cast<BinaryOperator>(Terminator)->getLHS(); 4106 break; 4107 4108 case Stmt::ObjCForCollectionStmtClass: 4109 return Terminator; 4110 } 4111 4112 return E ? E->IgnoreParens() : NULL; 4113} 4114 4115//===----------------------------------------------------------------------===// 4116// CFG Graphviz Visualization 4117//===----------------------------------------------------------------------===// 4118 4119 4120#ifndef NDEBUG 4121static StmtPrinterHelper* GraphHelper; 4122#endif 4123 4124void CFG::viewCFG(const LangOptions &LO) const { 4125#ifndef NDEBUG 4126 StmtPrinterHelper H(this, LO); 4127 GraphHelper = &H; 4128 llvm::ViewGraph(this,"CFG"); 4129 GraphHelper = NULL; 4130#endif 4131} 4132 4133namespace llvm { 4134template<> 4135struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 4136 4137 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 4138 4139 static std::string getNodeLabel(const CFGBlock *Node, const CFG* Graph) { 4140 4141#ifndef NDEBUG 4142 std::string OutSStr; 4143 llvm::raw_string_ostream Out(OutSStr); 4144 print_block(Out,Graph, *Node, GraphHelper, false, false); 4145 std::string& OutStr = Out.str(); 4146 4147 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 4148 4149 // Process string output to make it nicer... 4150 for (unsigned i = 0; i != OutStr.length(); ++i) 4151 if (OutStr[i] == '\n') { // Left justify 4152 OutStr[i] = '\\'; 4153 OutStr.insert(OutStr.begin()+i+1, 'l'); 4154 } 4155 4156 return OutStr; 4157#else 4158 return ""; 4159#endif 4160 } 4161}; 4162} // end namespace llvm 4163