CFG.cpp revision 247e9665d897a7bbbf60c1c0d3b6609c4504a961
1d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// 3d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// The LLVM Compiler Infrastructure 4d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// 5d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// This file is distributed under the University of Illinois Open Source 6d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// License. See LICENSE.TXT for details. 7d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// 8d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea//===----------------------------------------------------------------------===// 9d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// 10d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// This file defines the CFG and CFGBuilder classes for representing and 11d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// building Control-Flow Graphs (CFGs) from ASTs. 12d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea// 13d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea//===----------------------------------------------------------------------===// 14d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea 15d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "clang/Analysis/Support/SaveAndRestore.h" 16d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "clang/Analysis/CFG.h" 17d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "clang/AST/DeclCXX.h" 18d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "clang/AST/StmtVisitor.h" 19d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "clang/AST/PrettyPrinter.h" 20d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "clang/AST/CharUnits.h" 21d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "llvm/Support/GraphWriter.h" 22d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "llvm/Support/Allocator.h" 23d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "llvm/Support/Format.h" 24d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "llvm/ADT/DenseMap.h" 25d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "llvm/ADT/SmallPtrSet.h" 26d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea#include "llvm/ADT/OwningPtr.h" 27d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea 28d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Maleausing namespace clang; 29d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea 30d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Maleanamespace { 31d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea 32d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Maleastatic SourceLocation GetEndLoc(Decl* D) { 33d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea if (VarDecl* VD = dyn_cast<VarDecl>(D)) 34d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea if (Expr* Ex = VD->getInit()) 35d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea return Ex->getSourceRange().getEnd(); 36d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea return D->getLocation(); 37d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea} 38d2771ed2249c645019b7b1e46bdd677d2ed1cfe1Daniel Malea 39/// The CFG builder uses a recursive algorithm to build the CFG. When 40/// we process an expression, sometimes we know that we must add the 41/// subexpressions as block-level expressions. For example: 42/// 43/// exp1 || exp2 44/// 45/// When processing the '||' expression, we know that exp1 and exp2 46/// need to be added as block-level expressions, even though they 47/// might not normally need to be. AddStmtChoice records this 48/// contextual information. If AddStmtChoice is 'NotAlwaysAdd', then 49/// the builder has an option not to add a subexpression as a 50/// block-level expression. 51/// 52class AddStmtChoice { 53public: 54 enum Kind { NotAlwaysAdd = 0, AlwaysAdd = 1 }; 55 56 AddStmtChoice(Kind a_kind = NotAlwaysAdd) : kind(a_kind) {} 57 58 bool alwaysAdd() const { return kind & AlwaysAdd; } 59 60 /// Return a copy of this object, except with the 'always-add' bit 61 /// set as specified. 62 AddStmtChoice withAlwaysAdd(bool alwaysAdd) const { 63 return AddStmtChoice(alwaysAdd ? Kind(kind | AlwaysAdd) : 64 Kind(kind & ~AlwaysAdd)); 65 } 66 67private: 68 Kind kind; 69}; 70 71/// LocalScope - Node in tree of local scopes created for C++ implicit 72/// destructor calls generation. It contains list of automatic variables 73/// declared in the scope and link to position in previous scope this scope 74/// began in. 75/// 76/// The process of creating local scopes is as follows: 77/// - Init CFGBuilder::ScopePos with invalid position (equivalent for null), 78/// - Before processing statements in scope (e.g. CompoundStmt) create 79/// LocalScope object using CFGBuilder::ScopePos as link to previous scope 80/// and set CFGBuilder::ScopePos to the end of new scope, 81/// - On every occurrence of VarDecl increase CFGBuilder::ScopePos if it points 82/// at this VarDecl, 83/// - For every normal (without jump) end of scope add to CFGBlock destructors 84/// for objects in the current scope, 85/// - For every jump add to CFGBlock destructors for objects 86/// between CFGBuilder::ScopePos and local scope position saved for jump 87/// target. Thanks to C++ restrictions on goto jumps we can be sure that 88/// jump target position will be on the path to root from CFGBuilder::ScopePos 89/// (adding any variable that doesn't need constructor to be called to 90/// LocalScope can break this assumption), 91/// 92class LocalScope { 93public: 94 typedef BumpVector<VarDecl*> AutomaticVarsTy; 95 96 /// const_iterator - Iterates local scope backwards and jumps to previous 97 /// scope on reaching the beginning of currently iterated scope. 98 class const_iterator { 99 const LocalScope* Scope; 100 101 /// VarIter is guaranteed to be greater then 0 for every valid iterator. 102 /// Invalid iterator (with null Scope) has VarIter equal to 0. 103 unsigned VarIter; 104 105 public: 106 /// Create invalid iterator. Dereferencing invalid iterator is not allowed. 107 /// Incrementing invalid iterator is allowed and will result in invalid 108 /// iterator. 109 const_iterator() 110 : Scope(NULL), VarIter(0) {} 111 112 /// Create valid iterator. In case when S.Prev is an invalid iterator and 113 /// I is equal to 0, this will create invalid iterator. 114 const_iterator(const LocalScope& S, unsigned I) 115 : Scope(&S), VarIter(I) { 116 // Iterator to "end" of scope is not allowed. Handle it by going up 117 // in scopes tree possibly up to invalid iterator in the root. 118 if (VarIter == 0 && Scope) 119 *this = Scope->Prev; 120 } 121 122 VarDecl* const* operator->() const { 123 assert (Scope && "Dereferencing invalid iterator is not allowed"); 124 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 125 return &Scope->Vars[VarIter - 1]; 126 } 127 VarDecl* operator*() const { 128 return *this->operator->(); 129 } 130 131 const_iterator& operator++() { 132 if (!Scope) 133 return *this; 134 135 assert (VarIter != 0 && "Iterator has invalid value of VarIter member"); 136 --VarIter; 137 if (VarIter == 0) 138 *this = Scope->Prev; 139 return *this; 140 } 141 const_iterator operator++(int) { 142 const_iterator P = *this; 143 ++*this; 144 return P; 145 } 146 147 bool operator==(const const_iterator& rhs) const { 148 return Scope == rhs.Scope && VarIter == rhs.VarIter; 149 } 150 bool operator!=(const const_iterator& rhs) const { 151 return !(*this == rhs); 152 } 153 154 operator bool() const { 155 return *this != const_iterator(); 156 } 157 158 int distance(const_iterator L); 159 }; 160 161 friend class const_iterator; 162 163private: 164 BumpVectorContext ctx; 165 166 /// Automatic variables in order of declaration. 167 AutomaticVarsTy Vars; 168 /// Iterator to variable in previous scope that was declared just before 169 /// begin of this scope. 170 const_iterator Prev; 171 172public: 173 /// Constructs empty scope linked to previous scope in specified place. 174 LocalScope(BumpVectorContext &ctx, const_iterator P) 175 : ctx(ctx), Vars(ctx, 4), Prev(P) {} 176 177 /// Begin of scope in direction of CFG building (backwards). 178 const_iterator begin() const { return const_iterator(*this, Vars.size()); } 179 180 void addVar(VarDecl* VD) { 181 Vars.push_back(VD, ctx); 182 } 183}; 184 185/// distance - Calculates distance from this to L. L must be reachable from this 186/// (with use of ++ operator). Cost of calculating the distance is linear w.r.t. 187/// number of scopes between this and L. 188int LocalScope::const_iterator::distance(LocalScope::const_iterator L) { 189 int D = 0; 190 const_iterator F = *this; 191 while (F.Scope != L.Scope) { 192 assert (F != const_iterator() 193 && "L iterator is not reachable from F iterator."); 194 D += F.VarIter; 195 F = F.Scope->Prev; 196 } 197 D += F.VarIter - L.VarIter; 198 return D; 199} 200 201/// BlockScopePosPair - Structure for specifying position in CFG during its 202/// build process. It consists of CFGBlock that specifies position in CFG graph 203/// and LocalScope::const_iterator that specifies position in LocalScope graph. 204struct BlockScopePosPair { 205 BlockScopePosPair() : block(0) {} 206 BlockScopePosPair(CFGBlock* b, LocalScope::const_iterator scopePos) 207 : block(b), scopePosition(scopePos) {} 208 209 CFGBlock *block; 210 LocalScope::const_iterator scopePosition; 211}; 212 213/// TryResult - a class representing a variant over the values 214/// 'true', 'false', or 'unknown'. This is returned by tryEvaluateBool, 215/// and is used by the CFGBuilder to decide if a branch condition 216/// can be decided up front during CFG construction. 217class TryResult { 218 int X; 219public: 220 TryResult(bool b) : X(b ? 1 : 0) {} 221 TryResult() : X(-1) {} 222 223 bool isTrue() const { return X == 1; } 224 bool isFalse() const { return X == 0; } 225 bool isKnown() const { return X >= 0; } 226 void negate() { 227 assert(isKnown()); 228 X ^= 0x1; 229 } 230}; 231 232/// CFGBuilder - This class implements CFG construction from an AST. 233/// The builder is stateful: an instance of the builder should be used to only 234/// construct a single CFG. 235/// 236/// Example usage: 237/// 238/// CFGBuilder builder; 239/// CFG* cfg = builder.BuildAST(stmt1); 240/// 241/// CFG construction is done via a recursive walk of an AST. We actually parse 242/// the AST in reverse order so that the successor of a basic block is 243/// constructed prior to its predecessor. This allows us to nicely capture 244/// implicit fall-throughs without extra basic blocks. 245/// 246class CFGBuilder { 247 typedef BlockScopePosPair JumpTarget; 248 typedef BlockScopePosPair JumpSource; 249 250 ASTContext *Context; 251 llvm::OwningPtr<CFG> cfg; 252 253 CFGBlock* Block; 254 CFGBlock* Succ; 255 JumpTarget ContinueJumpTarget; 256 JumpTarget BreakJumpTarget; 257 CFGBlock* SwitchTerminatedBlock; 258 CFGBlock* DefaultCaseBlock; 259 CFGBlock* TryTerminatedBlock; 260 261 // Current position in local scope. 262 LocalScope::const_iterator ScopePos; 263 264 // LabelMap records the mapping from Label expressions to their jump targets. 265 typedef llvm::DenseMap<LabelDecl*, JumpTarget> LabelMapTy; 266 LabelMapTy LabelMap; 267 268 // A list of blocks that end with a "goto" that must be backpatched to their 269 // resolved targets upon completion of CFG construction. 270 typedef std::vector<JumpSource> BackpatchBlocksTy; 271 BackpatchBlocksTy BackpatchBlocks; 272 273 // A list of labels whose address has been taken (for indirect gotos). 274 typedef llvm::SmallPtrSet<LabelDecl*, 5> LabelSetTy; 275 LabelSetTy AddressTakenLabels; 276 277 bool badCFG; 278 const CFG::BuildOptions &BuildOpts; 279 280 // State to track for building switch statements. 281 bool switchExclusivelyCovered; 282 Expr::EvalResult *switchCond; 283 284public: 285 explicit CFGBuilder(ASTContext *astContext, 286 const CFG::BuildOptions &buildOpts) 287 : Context(astContext), cfg(new CFG()), // crew a new CFG 288 Block(NULL), Succ(NULL), 289 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 290 TryTerminatedBlock(NULL), badCFG(false), BuildOpts(buildOpts), 291 switchExclusivelyCovered(false), switchCond(0) {} 292 293 // buildCFG - Used by external clients to construct the CFG. 294 CFG* buildCFG(const Decl *D, Stmt *Statement); 295 296private: 297 // Visitors to walk an AST and construct the CFG. 298 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 299 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 300 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 301 CFGBlock *VisitBreakStmt(BreakStmt *B); 302 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 303 CFGBlock *VisitExprWithCleanups(ExprWithCleanups *E, 304 AddStmtChoice asc); 305 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 306 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 307 CFGBlock *VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 308 AddStmtChoice asc); 309 CFGBlock *VisitCXXConstructExpr(CXXConstructExpr *C, AddStmtChoice asc); 310 CFGBlock *VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 311 AddStmtChoice asc); 312 CFGBlock *VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 313 AddStmtChoice asc); 314 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 315 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 316 CFGBlock *VisitCaseStmt(CaseStmt *C); 317 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 318 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 319 CFGBlock *VisitConditionalOperator(AbstractConditionalOperator *C, 320 AddStmtChoice asc); 321 CFGBlock *VisitContinueStmt(ContinueStmt *C); 322 CFGBlock *VisitDeclStmt(DeclStmt *DS); 323 CFGBlock *VisitDeclSubExpr(DeclStmt* DS); 324 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 325 CFGBlock *VisitDoStmt(DoStmt *D); 326 CFGBlock *VisitForStmt(ForStmt *F); 327 CFGBlock *VisitGotoStmt(GotoStmt* G); 328 CFGBlock *VisitIfStmt(IfStmt *I); 329 CFGBlock *VisitImplicitCastExpr(ImplicitCastExpr *E, AddStmtChoice asc); 330 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 331 CFGBlock *VisitLabelStmt(LabelStmt *L); 332 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 333 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 334 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 335 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 336 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 337 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 338 CFGBlock *VisitReturnStmt(ReturnStmt* R); 339 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 340 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 341 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 342 CFGBlock *VisitUnaryOperator(UnaryOperator *U, AddStmtChoice asc); 343 CFGBlock *VisitWhileStmt(WhileStmt *W); 344 345 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 346 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 347 CFGBlock *VisitChildren(Stmt* S); 348 349 // Visitors to walk an AST and generate destructors of temporaries in 350 // full expression. 351 CFGBlock *VisitForTemporaryDtors(Stmt *E, bool BindToTemporary = false); 352 CFGBlock *VisitChildrenForTemporaryDtors(Stmt *E); 353 CFGBlock *VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E); 354 CFGBlock *VisitCXXBindTemporaryExprForTemporaryDtors(CXXBindTemporaryExpr *E, 355 bool BindToTemporary); 356 CFGBlock * 357 VisitConditionalOperatorForTemporaryDtors(AbstractConditionalOperator *E, 358 bool BindToTemporary); 359 360 // NYS == Not Yet Supported 361 CFGBlock* NYS() { 362 badCFG = true; 363 return Block; 364 } 365 366 void autoCreateBlock() { if (!Block) Block = createBlock(); } 367 CFGBlock *createBlock(bool add_successor = true); 368 369 CFGBlock *addStmt(Stmt *S) { 370 return Visit(S, AddStmtChoice::AlwaysAdd); 371 } 372 CFGBlock *addInitializer(CXXCtorInitializer *I); 373 void addAutomaticObjDtors(LocalScope::const_iterator B, 374 LocalScope::const_iterator E, Stmt* S); 375 void addImplicitDtorsForDestructor(const CXXDestructorDecl *DD); 376 377 // Local scopes creation. 378 LocalScope* createOrReuseLocalScope(LocalScope* Scope); 379 380 void addLocalScopeForStmt(Stmt* S); 381 LocalScope* addLocalScopeForDeclStmt(DeclStmt* DS, LocalScope* Scope = NULL); 382 LocalScope* addLocalScopeForVarDecl(VarDecl* VD, LocalScope* Scope = NULL); 383 384 void addLocalScopeAndDtors(Stmt* S); 385 386 // Interface to CFGBlock - adding CFGElements. 387 void appendStmt(CFGBlock *B, Stmt *S) { 388 B->appendStmt(S, cfg->getBumpVectorContext()); 389 } 390 void appendInitializer(CFGBlock *B, CXXCtorInitializer *I) { 391 B->appendInitializer(I, cfg->getBumpVectorContext()); 392 } 393 void appendBaseDtor(CFGBlock *B, const CXXBaseSpecifier *BS) { 394 B->appendBaseDtor(BS, cfg->getBumpVectorContext()); 395 } 396 void appendMemberDtor(CFGBlock *B, FieldDecl *FD) { 397 B->appendMemberDtor(FD, cfg->getBumpVectorContext()); 398 } 399 void appendTemporaryDtor(CFGBlock *B, CXXBindTemporaryExpr *E) { 400 B->appendTemporaryDtor(E, cfg->getBumpVectorContext()); 401 } 402 403 void insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 404 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S); 405 void appendAutomaticObjDtors(CFGBlock* Blk, LocalScope::const_iterator B, 406 LocalScope::const_iterator E, Stmt* S); 407 void prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 408 LocalScope::const_iterator B, LocalScope::const_iterator E); 409 410 void addSuccessor(CFGBlock *B, CFGBlock *S) { 411 B->addSuccessor(S, cfg->getBumpVectorContext()); 412 } 413 414 /// Try and evaluate an expression to an integer constant. 415 bool tryEvaluate(Expr *S, Expr::EvalResult &outResult) { 416 if (!BuildOpts.PruneTriviallyFalseEdges) 417 return false; 418 return !S->isTypeDependent() && 419 !S->isValueDependent() && 420 S->Evaluate(outResult, *Context); 421 } 422 423 /// tryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 424 /// if we can evaluate to a known value, otherwise return -1. 425 TryResult tryEvaluateBool(Expr *S) { 426 Expr::EvalResult Result; 427 if (!tryEvaluate(S, Result)) 428 return TryResult(); 429 430 if (Result.Val.isInt()) 431 return Result.Val.getInt().getBoolValue(); 432 433 if (Result.Val.isLValue()) { 434 Expr *e = Result.Val.getLValueBase(); 435 const CharUnits &c = Result.Val.getLValueOffset(); 436 if (!e && c.isZero()) 437 return false; 438 } 439 return TryResult(); 440 } 441 442}; 443 444// FIXME: Add support for dependent-sized array types in C++? 445// Does it even make sense to build a CFG for an uninstantiated template? 446static const VariableArrayType *FindVA(const Type *t) { 447 while (const ArrayType *vt = dyn_cast<ArrayType>(t)) { 448 if (const VariableArrayType *vat = dyn_cast<VariableArrayType>(vt)) 449 if (vat->getSizeExpr()) 450 return vat; 451 452 t = vt->getElementType().getTypePtr(); 453 } 454 455 return 0; 456} 457 458/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 459/// arbitrary statement. Examples include a single expression or a function 460/// body (compound statement). The ownership of the returned CFG is 461/// transferred to the caller. If CFG construction fails, this method returns 462/// NULL. 463CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement) { 464 assert(cfg.get()); 465 if (!Statement) 466 return NULL; 467 468 // Create an empty block that will serve as the exit block for the CFG. Since 469 // this is the first block added to the CFG, it will be implicitly registered 470 // as the exit block. 471 Succ = createBlock(); 472 assert(Succ == &cfg->getExit()); 473 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 474 475 if (BuildOpts.AddImplicitDtors) 476 if (const CXXDestructorDecl *DD = dyn_cast_or_null<CXXDestructorDecl>(D)) 477 addImplicitDtorsForDestructor(DD); 478 479 // Visit the statements and create the CFG. 480 CFGBlock *B = addStmt(Statement); 481 482 if (badCFG) 483 return NULL; 484 485 // For C++ constructor add initializers to CFG. 486 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 487 for (CXXConstructorDecl::init_const_reverse_iterator I = CD->init_rbegin(), 488 E = CD->init_rend(); I != E; ++I) { 489 B = addInitializer(*I); 490 if (badCFG) 491 return NULL; 492 } 493 } 494 495 if (B) 496 Succ = B; 497 498 // Backpatch the gotos whose label -> block mappings we didn't know when we 499 // encountered them. 500 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 501 E = BackpatchBlocks.end(); I != E; ++I ) { 502 503 CFGBlock* B = I->block; 504 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 505 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 506 507 // If there is no target for the goto, then we are looking at an 508 // incomplete AST. Handle this by not registering a successor. 509 if (LI == LabelMap.end()) continue; 510 511 JumpTarget JT = LI->second; 512 prependAutomaticObjDtorsWithTerminator(B, I->scopePosition, 513 JT.scopePosition); 514 addSuccessor(B, JT.block); 515 } 516 517 // Add successors to the Indirect Goto Dispatch block (if we have one). 518 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 519 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 520 E = AddressTakenLabels.end(); I != E; ++I ) { 521 522 // Lookup the target block. 523 LabelMapTy::iterator LI = LabelMap.find(*I); 524 525 // If there is no target block that contains label, then we are looking 526 // at an incomplete AST. Handle this by not registering a successor. 527 if (LI == LabelMap.end()) continue; 528 529 addSuccessor(B, LI->second.block); 530 } 531 532 // Create an empty entry block that has no predecessors. 533 cfg->setEntry(createBlock()); 534 535 return cfg.take(); 536} 537 538/// createBlock - Used to lazily create blocks that are connected 539/// to the current (global) succcessor. 540CFGBlock* CFGBuilder::createBlock(bool add_successor) { 541 CFGBlock* B = cfg->createBlock(); 542 if (add_successor && Succ) 543 addSuccessor(B, Succ); 544 return B; 545} 546 547/// addInitializer - Add C++ base or member initializer element to CFG. 548CFGBlock *CFGBuilder::addInitializer(CXXCtorInitializer *I) { 549 if (!BuildOpts.AddInitializers) 550 return Block; 551 552 bool IsReference = false; 553 bool HasTemporaries = false; 554 555 // Destructors of temporaries in initialization expression should be called 556 // after initialization finishes. 557 Expr *Init = I->getInit(); 558 if (Init) { 559 if (FieldDecl *FD = I->getAnyMember()) 560 IsReference = FD->getType()->isReferenceType(); 561 HasTemporaries = isa<ExprWithCleanups>(Init); 562 563 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 564 // Generate destructors for temporaries in initialization expression. 565 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 566 IsReference); 567 } 568 } 569 570 autoCreateBlock(); 571 appendInitializer(Block, I); 572 573 if (Init) { 574 if (HasTemporaries) { 575 // For expression with temporaries go directly to subexpression to omit 576 // generating destructors for the second time. 577 return Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 578 } 579 return Visit(Init); 580 } 581 582 return Block; 583} 584 585/// addAutomaticObjDtors - Add to current block automatic objects destructors 586/// for objects in range of local scope positions. Use S as trigger statement 587/// for destructors. 588void CFGBuilder::addAutomaticObjDtors(LocalScope::const_iterator B, 589 LocalScope::const_iterator E, Stmt* S) { 590 if (!BuildOpts.AddImplicitDtors) 591 return; 592 593 if (B == E) 594 return; 595 596 autoCreateBlock(); 597 appendAutomaticObjDtors(Block, B, E, S); 598} 599 600/// addImplicitDtorsForDestructor - Add implicit destructors generated for 601/// base and member objects in destructor. 602void CFGBuilder::addImplicitDtorsForDestructor(const CXXDestructorDecl *DD) { 603 assert (BuildOpts.AddImplicitDtors 604 && "Can be called only when dtors should be added"); 605 const CXXRecordDecl *RD = DD->getParent(); 606 607 // At the end destroy virtual base objects. 608 for (CXXRecordDecl::base_class_const_iterator VI = RD->vbases_begin(), 609 VE = RD->vbases_end(); VI != VE; ++VI) { 610 const CXXRecordDecl *CD = VI->getType()->getAsCXXRecordDecl(); 611 if (!CD->hasTrivialDestructor()) { 612 autoCreateBlock(); 613 appendBaseDtor(Block, VI); 614 } 615 } 616 617 // Before virtual bases destroy direct base objects. 618 for (CXXRecordDecl::base_class_const_iterator BI = RD->bases_begin(), 619 BE = RD->bases_end(); BI != BE; ++BI) { 620 if (!BI->isVirtual()) { 621 const CXXRecordDecl *CD = BI->getType()->getAsCXXRecordDecl(); 622 if (!CD->hasTrivialDestructor()) { 623 autoCreateBlock(); 624 appendBaseDtor(Block, BI); 625 } 626 } 627 } 628 629 // First destroy member objects. 630 for (CXXRecordDecl::field_iterator FI = RD->field_begin(), 631 FE = RD->field_end(); FI != FE; ++FI) { 632 // Check for constant size array. Set type to array element type. 633 QualType QT = FI->getType(); 634 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 635 if (AT->getSize() == 0) 636 continue; 637 QT = AT->getElementType(); 638 } 639 640 if (const CXXRecordDecl *CD = QT->getAsCXXRecordDecl()) 641 if (!CD->hasTrivialDestructor()) { 642 autoCreateBlock(); 643 appendMemberDtor(Block, *FI); 644 } 645 } 646} 647 648/// createOrReuseLocalScope - If Scope is NULL create new LocalScope. Either 649/// way return valid LocalScope object. 650LocalScope* CFGBuilder::createOrReuseLocalScope(LocalScope* Scope) { 651 if (!Scope) { 652 llvm::BumpPtrAllocator &alloc = cfg->getAllocator(); 653 Scope = alloc.Allocate<LocalScope>(); 654 BumpVectorContext ctx(alloc); 655 new (Scope) LocalScope(ctx, ScopePos); 656 } 657 return Scope; 658} 659 660/// addLocalScopeForStmt - Add LocalScope to local scopes tree for statement 661/// that should create implicit scope (e.g. if/else substatements). 662void CFGBuilder::addLocalScopeForStmt(Stmt* S) { 663 if (!BuildOpts.AddImplicitDtors) 664 return; 665 666 LocalScope *Scope = 0; 667 668 // For compound statement we will be creating explicit scope. 669 if (CompoundStmt *CS = dyn_cast<CompoundStmt>(S)) { 670 for (CompoundStmt::body_iterator BI = CS->body_begin(), BE = CS->body_end() 671 ; BI != BE; ++BI) { 672 Stmt *SI = *BI; 673 if (LabelStmt *LS = dyn_cast<LabelStmt>(SI)) 674 SI = LS->getSubStmt(); 675 if (DeclStmt *DS = dyn_cast<DeclStmt>(SI)) 676 Scope = addLocalScopeForDeclStmt(DS, Scope); 677 } 678 return; 679 } 680 681 // For any other statement scope will be implicit and as such will be 682 // interesting only for DeclStmt. 683 if (LabelStmt *LS = dyn_cast<LabelStmt>(S)) 684 S = LS->getSubStmt(); 685 if (DeclStmt *DS = dyn_cast<DeclStmt>(S)) 686 addLocalScopeForDeclStmt(DS); 687} 688 689/// addLocalScopeForDeclStmt - Add LocalScope for declaration statement. Will 690/// reuse Scope if not NULL. 691LocalScope* CFGBuilder::addLocalScopeForDeclStmt(DeclStmt* DS, 692 LocalScope* Scope) { 693 if (!BuildOpts.AddImplicitDtors) 694 return Scope; 695 696 for (DeclStmt::decl_iterator DI = DS->decl_begin(), DE = DS->decl_end() 697 ; DI != DE; ++DI) { 698 if (VarDecl* VD = dyn_cast<VarDecl>(*DI)) 699 Scope = addLocalScopeForVarDecl(VD, Scope); 700 } 701 return Scope; 702} 703 704/// addLocalScopeForVarDecl - Add LocalScope for variable declaration. It will 705/// create add scope for automatic objects and temporary objects bound to 706/// const reference. Will reuse Scope if not NULL. 707LocalScope* CFGBuilder::addLocalScopeForVarDecl(VarDecl* VD, 708 LocalScope* Scope) { 709 if (!BuildOpts.AddImplicitDtors) 710 return Scope; 711 712 // Check if variable is local. 713 switch (VD->getStorageClass()) { 714 case SC_None: 715 case SC_Auto: 716 case SC_Register: 717 break; 718 default: return Scope; 719 } 720 721 // Check for const references bound to temporary. Set type to pointee. 722 QualType QT = VD->getType(); 723 if (const ReferenceType* RT = QT.getTypePtr()->getAs<ReferenceType>()) { 724 QT = RT->getPointeeType(); 725 if (!QT.isConstQualified()) 726 return Scope; 727 if (!VD->getInit() || !VD->getInit()->Classify(*Context).isRValue()) 728 return Scope; 729 } 730 731 // Check for constant size array. Set type to array element type. 732 if (const ConstantArrayType *AT = Context->getAsConstantArrayType(QT)) { 733 if (AT->getSize() == 0) 734 return Scope; 735 QT = AT->getElementType(); 736 } 737 738 // Check if type is a C++ class with non-trivial destructor. 739 if (const CXXRecordDecl* CD = QT->getAsCXXRecordDecl()) 740 if (!CD->hasTrivialDestructor()) { 741 // Add the variable to scope 742 Scope = createOrReuseLocalScope(Scope); 743 Scope->addVar(VD); 744 ScopePos = Scope->begin(); 745 } 746 return Scope; 747} 748 749/// addLocalScopeAndDtors - For given statement add local scope for it and 750/// add destructors that will cleanup the scope. Will reuse Scope if not NULL. 751void CFGBuilder::addLocalScopeAndDtors(Stmt* S) { 752 if (!BuildOpts.AddImplicitDtors) 753 return; 754 755 LocalScope::const_iterator scopeBeginPos = ScopePos; 756 addLocalScopeForStmt(S); 757 addAutomaticObjDtors(ScopePos, scopeBeginPos, S); 758} 759 760/// insertAutomaticObjDtors - Insert destructor CFGElements for variables with 761/// automatic storage duration to CFGBlock's elements vector. Insertion will be 762/// performed in place specified with iterator. 763void CFGBuilder::insertAutomaticObjDtors(CFGBlock* Blk, CFGBlock::iterator I, 764 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 765 BumpVectorContext& C = cfg->getBumpVectorContext(); 766 I = Blk->beginAutomaticObjDtorsInsert(I, B.distance(E), C); 767 while (B != E) 768 I = Blk->insertAutomaticObjDtor(I, *B++, S); 769} 770 771/// appendAutomaticObjDtors - Append destructor CFGElements for variables with 772/// automatic storage duration to CFGBlock's elements vector. Elements will be 773/// appended to physical end of the vector which happens to be logical 774/// beginning. 775void CFGBuilder::appendAutomaticObjDtors(CFGBlock* Blk, 776 LocalScope::const_iterator B, LocalScope::const_iterator E, Stmt* S) { 777 insertAutomaticObjDtors(Blk, Blk->begin(), B, E, S); 778} 779 780/// prependAutomaticObjDtorsWithTerminator - Prepend destructor CFGElements for 781/// variables with automatic storage duration to CFGBlock's elements vector. 782/// Elements will be prepended to physical beginning of the vector which 783/// happens to be logical end. Use blocks terminator as statement that specifies 784/// destructors call site. 785void CFGBuilder::prependAutomaticObjDtorsWithTerminator(CFGBlock* Blk, 786 LocalScope::const_iterator B, LocalScope::const_iterator E) { 787 insertAutomaticObjDtors(Blk, Blk->end(), B, E, Blk->getTerminator()); 788} 789 790/// Visit - Walk the subtree of a statement and add extra 791/// blocks for ternary operators, &&, and ||. We also process "," and 792/// DeclStmts (which may contain nested control-flow). 793CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 794tryAgain: 795 if (!S) { 796 badCFG = true; 797 return 0; 798 } 799 switch (S->getStmtClass()) { 800 default: 801 return VisitStmt(S, asc); 802 803 case Stmt::AddrLabelExprClass: 804 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 805 806 case Stmt::BinaryConditionalOperatorClass: 807 return VisitConditionalOperator(cast<BinaryConditionalOperator>(S), asc); 808 809 case Stmt::BinaryOperatorClass: 810 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 811 812 case Stmt::BlockExprClass: 813 return VisitBlockExpr(cast<BlockExpr>(S), asc); 814 815 case Stmt::BreakStmtClass: 816 return VisitBreakStmt(cast<BreakStmt>(S)); 817 818 case Stmt::CallExprClass: 819 case Stmt::CXXOperatorCallExprClass: 820 return VisitCallExpr(cast<CallExpr>(S), asc); 821 822 case Stmt::CaseStmtClass: 823 return VisitCaseStmt(cast<CaseStmt>(S)); 824 825 case Stmt::ChooseExprClass: 826 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 827 828 case Stmt::CompoundStmtClass: 829 return VisitCompoundStmt(cast<CompoundStmt>(S)); 830 831 case Stmt::ConditionalOperatorClass: 832 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 833 834 case Stmt::ContinueStmtClass: 835 return VisitContinueStmt(cast<ContinueStmt>(S)); 836 837 case Stmt::CXXCatchStmtClass: 838 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 839 840 case Stmt::ExprWithCleanupsClass: 841 return VisitExprWithCleanups(cast<ExprWithCleanups>(S), asc); 842 843 case Stmt::CXXBindTemporaryExprClass: 844 return VisitCXXBindTemporaryExpr(cast<CXXBindTemporaryExpr>(S), asc); 845 846 case Stmt::CXXConstructExprClass: 847 return VisitCXXConstructExpr(cast<CXXConstructExpr>(S), asc); 848 849 case Stmt::CXXFunctionalCastExprClass: 850 return VisitCXXFunctionalCastExpr(cast<CXXFunctionalCastExpr>(S), asc); 851 852 case Stmt::CXXTemporaryObjectExprClass: 853 return VisitCXXTemporaryObjectExpr(cast<CXXTemporaryObjectExpr>(S), asc); 854 855 case Stmt::CXXMemberCallExprClass: 856 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 857 858 case Stmt::CXXThrowExprClass: 859 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 860 861 case Stmt::CXXTryStmtClass: 862 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 863 864 case Stmt::DeclStmtClass: 865 return VisitDeclStmt(cast<DeclStmt>(S)); 866 867 case Stmt::DefaultStmtClass: 868 return VisitDefaultStmt(cast<DefaultStmt>(S)); 869 870 case Stmt::DoStmtClass: 871 return VisitDoStmt(cast<DoStmt>(S)); 872 873 case Stmt::ForStmtClass: 874 return VisitForStmt(cast<ForStmt>(S)); 875 876 case Stmt::GotoStmtClass: 877 return VisitGotoStmt(cast<GotoStmt>(S)); 878 879 case Stmt::IfStmtClass: 880 return VisitIfStmt(cast<IfStmt>(S)); 881 882 case Stmt::ImplicitCastExprClass: 883 return VisitImplicitCastExpr(cast<ImplicitCastExpr>(S), asc); 884 885 case Stmt::IndirectGotoStmtClass: 886 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 887 888 case Stmt::LabelStmtClass: 889 return VisitLabelStmt(cast<LabelStmt>(S)); 890 891 case Stmt::MemberExprClass: 892 return VisitMemberExpr(cast<MemberExpr>(S), asc); 893 894 case Stmt::ObjCAtCatchStmtClass: 895 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 896 897 case Stmt::ObjCAtSynchronizedStmtClass: 898 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 899 900 case Stmt::ObjCAtThrowStmtClass: 901 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 902 903 case Stmt::ObjCAtTryStmtClass: 904 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 905 906 case Stmt::ObjCForCollectionStmtClass: 907 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 908 909 case Stmt::ParenExprClass: 910 S = cast<ParenExpr>(S)->getSubExpr(); 911 goto tryAgain; 912 913 case Stmt::NullStmtClass: 914 return Block; 915 916 case Stmt::ReturnStmtClass: 917 return VisitReturnStmt(cast<ReturnStmt>(S)); 918 919 case Stmt::SizeOfAlignOfExprClass: 920 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 921 922 case Stmt::StmtExprClass: 923 return VisitStmtExpr(cast<StmtExpr>(S), asc); 924 925 case Stmt::SwitchStmtClass: 926 return VisitSwitchStmt(cast<SwitchStmt>(S)); 927 928 case Stmt::UnaryOperatorClass: 929 return VisitUnaryOperator(cast<UnaryOperator>(S), asc); 930 931 case Stmt::WhileStmtClass: 932 return VisitWhileStmt(cast<WhileStmt>(S)); 933 } 934} 935 936CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 937 if (asc.alwaysAdd()) { 938 autoCreateBlock(); 939 appendStmt(Block, S); 940 } 941 942 return VisitChildren(S); 943} 944 945/// VisitChildren - Visit the children of a Stmt. 946CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 947 CFGBlock *lastBlock = Block; 948 for (Stmt::child_range I = Terminator->children(); I; ++I) 949 if (Stmt *child = *I) 950 if (CFGBlock *b = Visit(child)) 951 lastBlock = b; 952 953 return lastBlock; 954} 955 956CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 957 AddStmtChoice asc) { 958 AddressTakenLabels.insert(A->getLabel()); 959 960 if (asc.alwaysAdd()) { 961 autoCreateBlock(); 962 appendStmt(Block, A); 963 } 964 965 return Block; 966} 967 968CFGBlock *CFGBuilder::VisitUnaryOperator(UnaryOperator *U, 969 AddStmtChoice asc) { 970 if (asc.alwaysAdd()) { 971 autoCreateBlock(); 972 appendStmt(Block, U); 973 } 974 975 return Visit(U->getSubExpr(), AddStmtChoice()); 976} 977 978CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 979 AddStmtChoice asc) { 980 if (B->isLogicalOp()) { // && or || 981 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 982 appendStmt(ConfluenceBlock, B); 983 984 if (badCFG) 985 return 0; 986 987 // create the block evaluating the LHS 988 CFGBlock* LHSBlock = createBlock(false); 989 LHSBlock->setTerminator(B); 990 991 // create the block evaluating the RHS 992 Succ = ConfluenceBlock; 993 Block = NULL; 994 CFGBlock* RHSBlock = addStmt(B->getRHS()); 995 996 if (RHSBlock) { 997 if (badCFG) 998 return 0; 999 } else { 1000 // Create an empty block for cases where the RHS doesn't require 1001 // any explicit statements in the CFG. 1002 RHSBlock = createBlock(); 1003 } 1004 1005 // See if this is a known constant. 1006 TryResult KnownVal = tryEvaluateBool(B->getLHS()); 1007 if (KnownVal.isKnown() && (B->getOpcode() == BO_LOr)) 1008 KnownVal.negate(); 1009 1010 // Now link the LHSBlock with RHSBlock. 1011 if (B->getOpcode() == BO_LOr) { 1012 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1013 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1014 } else { 1015 assert(B->getOpcode() == BO_LAnd); 1016 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 1017 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 1018 } 1019 1020 // Generate the blocks for evaluating the LHS. 1021 Block = LHSBlock; 1022 return addStmt(B->getLHS()); 1023 } 1024 1025 if (B->getOpcode() == BO_Comma) { // , 1026 autoCreateBlock(); 1027 appendStmt(Block, B); 1028 addStmt(B->getRHS()); 1029 return addStmt(B->getLHS()); 1030 } 1031 1032 if (B->isAssignmentOp()) { 1033 if (asc.alwaysAdd()) { 1034 autoCreateBlock(); 1035 appendStmt(Block, B); 1036 } 1037 Visit(B->getLHS()); 1038 return Visit(B->getRHS()); 1039 } 1040 1041 if (asc.alwaysAdd()) { 1042 autoCreateBlock(); 1043 appendStmt(Block, B); 1044 } 1045 1046 CFGBlock *RBlock = Visit(B->getRHS()); 1047 CFGBlock *LBlock = Visit(B->getLHS()); 1048 // If visiting RHS causes us to finish 'Block', e.g. the RHS is a StmtExpr 1049 // containing a DoStmt, and the LHS doesn't create a new block, then we should 1050 // return RBlock. Otherwise we'll incorrectly return NULL. 1051 return (LBlock ? LBlock : RBlock); 1052} 1053 1054CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 1055 if (asc.alwaysAdd()) { 1056 autoCreateBlock(); 1057 appendStmt(Block, E); 1058 } 1059 return Block; 1060} 1061 1062CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 1063 // "break" is a control-flow statement. Thus we stop processing the current 1064 // block. 1065 if (badCFG) 1066 return 0; 1067 1068 // Now create a new block that ends with the break statement. 1069 Block = createBlock(false); 1070 Block->setTerminator(B); 1071 1072 // If there is no target for the break, then we are looking at an incomplete 1073 // AST. This means that the CFG cannot be constructed. 1074 if (BreakJumpTarget.block) { 1075 addAutomaticObjDtors(ScopePos, BreakJumpTarget.scopePosition, B); 1076 addSuccessor(Block, BreakJumpTarget.block); 1077 } else 1078 badCFG = true; 1079 1080 1081 return Block; 1082} 1083 1084static bool CanThrow(Expr *E) { 1085 QualType Ty = E->getType(); 1086 if (Ty->isFunctionPointerType()) 1087 Ty = Ty->getAs<PointerType>()->getPointeeType(); 1088 else if (Ty->isBlockPointerType()) 1089 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 1090 1091 const FunctionType *FT = Ty->getAs<FunctionType>(); 1092 if (FT) { 1093 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 1094 if (Proto->hasEmptyExceptionSpec()) 1095 return false; 1096 } 1097 return true; 1098} 1099 1100CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 1101 // If this is a call to a no-return function, this stops the block here. 1102 bool NoReturn = false; 1103 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 1104 NoReturn = true; 1105 } 1106 1107 bool AddEHEdge = false; 1108 1109 // Languages without exceptions are assumed to not throw. 1110 if (Context->getLangOptions().Exceptions) { 1111 if (BuildOpts.AddEHEdges) 1112 AddEHEdge = true; 1113 } 1114 1115 if (FunctionDecl *FD = C->getDirectCallee()) { 1116 if (FD->hasAttr<NoReturnAttr>()) 1117 NoReturn = true; 1118 if (FD->hasAttr<NoThrowAttr>()) 1119 AddEHEdge = false; 1120 } 1121 1122 if (!CanThrow(C->getCallee())) 1123 AddEHEdge = false; 1124 1125 if (!NoReturn && !AddEHEdge) 1126 return VisitStmt(C, asc.withAlwaysAdd(true)); 1127 1128 if (Block) { 1129 Succ = Block; 1130 if (badCFG) 1131 return 0; 1132 } 1133 1134 Block = createBlock(!NoReturn); 1135 appendStmt(Block, C); 1136 1137 if (NoReturn) { 1138 // Wire this to the exit block directly. 1139 addSuccessor(Block, &cfg->getExit()); 1140 } 1141 if (AddEHEdge) { 1142 // Add exceptional edges. 1143 if (TryTerminatedBlock) 1144 addSuccessor(Block, TryTerminatedBlock); 1145 else 1146 addSuccessor(Block, &cfg->getExit()); 1147 } 1148 1149 return VisitChildren(C); 1150} 1151 1152CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 1153 AddStmtChoice asc) { 1154 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1155 appendStmt(ConfluenceBlock, C); 1156 if (badCFG) 1157 return 0; 1158 1159 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1160 Succ = ConfluenceBlock; 1161 Block = NULL; 1162 CFGBlock* LHSBlock = Visit(C->getLHS(), alwaysAdd); 1163 if (badCFG) 1164 return 0; 1165 1166 Succ = ConfluenceBlock; 1167 Block = NULL; 1168 CFGBlock* RHSBlock = Visit(C->getRHS(), alwaysAdd); 1169 if (badCFG) 1170 return 0; 1171 1172 Block = createBlock(false); 1173 // See if this is a known constant. 1174 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1175 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1176 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1177 Block->setTerminator(C); 1178 return addStmt(C->getCond()); 1179} 1180 1181 1182CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 1183 addLocalScopeAndDtors(C); 1184 CFGBlock* LastBlock = Block; 1185 1186 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 1187 I != E; ++I ) { 1188 // If we hit a segment of code just containing ';' (NullStmts), we can 1189 // get a null block back. In such cases, just use the LastBlock 1190 if (CFGBlock *newBlock = addStmt(*I)) 1191 LastBlock = newBlock; 1192 1193 if (badCFG) 1194 return NULL; 1195 } 1196 1197 return LastBlock; 1198} 1199 1200CFGBlock *CFGBuilder::VisitConditionalOperator(AbstractConditionalOperator *C, 1201 AddStmtChoice asc) { 1202 const BinaryConditionalOperator *BCO = dyn_cast<BinaryConditionalOperator>(C); 1203 const OpaqueValueExpr *opaqueValue = (BCO ? BCO->getOpaqueValue() : NULL); 1204 1205 // Create the confluence block that will "merge" the results of the ternary 1206 // expression. 1207 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 1208 appendStmt(ConfluenceBlock, C); 1209 if (badCFG) 1210 return 0; 1211 1212 AddStmtChoice alwaysAdd = asc.withAlwaysAdd(true); 1213 1214 // Create a block for the LHS expression if there is an LHS expression. A 1215 // GCC extension allows LHS to be NULL, causing the condition to be the 1216 // value that is returned instead. 1217 // e.g: x ?: y is shorthand for: x ? x : y; 1218 Succ = ConfluenceBlock; 1219 Block = NULL; 1220 CFGBlock* LHSBlock = 0; 1221 const Expr *trueExpr = C->getTrueExpr(); 1222 if (trueExpr != opaqueValue) { 1223 LHSBlock = Visit(C->getTrueExpr(), alwaysAdd); 1224 if (badCFG) 1225 return 0; 1226 Block = NULL; 1227 } 1228 else 1229 LHSBlock = ConfluenceBlock; 1230 1231 // Create the block for the RHS expression. 1232 Succ = ConfluenceBlock; 1233 CFGBlock* RHSBlock = Visit(C->getFalseExpr(), alwaysAdd); 1234 if (badCFG) 1235 return 0; 1236 1237 // Create the block that will contain the condition. 1238 Block = createBlock(false); 1239 1240 // See if this is a known constant. 1241 const TryResult& KnownVal = tryEvaluateBool(C->getCond()); 1242 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 1243 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 1244 Block->setTerminator(C); 1245 Expr *condExpr = C->getCond(); 1246 1247 if (opaqueValue) { 1248 // Run the condition expression if it's not trivially expressed in 1249 // terms of the opaque value (or if there is no opaque value). 1250 if (condExpr != opaqueValue) 1251 addStmt(condExpr); 1252 1253 // Before that, run the common subexpression if there was one. 1254 // At least one of this or the above will be run. 1255 return addStmt(BCO->getCommon()); 1256 } 1257 1258 return addStmt(condExpr); 1259} 1260 1261CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 1262 if (DS->isSingleDecl()) 1263 return VisitDeclSubExpr(DS); 1264 1265 CFGBlock *B = 0; 1266 1267 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 1268 typedef llvm::SmallVector<Decl*,10> BufTy; 1269 BufTy Buf(DS->decl_begin(), DS->decl_end()); 1270 1271 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 1272 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 1273 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 1274 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 1275 1276 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 1277 // automatically freed with the CFG. 1278 DeclGroupRef DG(*I); 1279 Decl *D = *I; 1280 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 1281 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 1282 1283 // Append the fake DeclStmt to block. 1284 B = VisitDeclSubExpr(DSNew); 1285 } 1286 1287 return B; 1288} 1289 1290/// VisitDeclSubExpr - Utility method to add block-level expressions for 1291/// DeclStmts and initializers in them. 1292CFGBlock *CFGBuilder::VisitDeclSubExpr(DeclStmt* DS) { 1293 assert(DS->isSingleDecl() && "Can handle single declarations only."); 1294 1295 VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl()); 1296 1297 if (!VD) { 1298 autoCreateBlock(); 1299 appendStmt(Block, DS); 1300 return Block; 1301 } 1302 1303 bool IsReference = false; 1304 bool HasTemporaries = false; 1305 1306 // Destructors of temporaries in initialization expression should be called 1307 // after initialization finishes. 1308 Expr *Init = VD->getInit(); 1309 if (Init) { 1310 IsReference = VD->getType()->isReferenceType(); 1311 HasTemporaries = isa<ExprWithCleanups>(Init); 1312 1313 if (BuildOpts.AddImplicitDtors && HasTemporaries) { 1314 // Generate destructors for temporaries in initialization expression. 1315 VisitForTemporaryDtors(cast<ExprWithCleanups>(Init)->getSubExpr(), 1316 IsReference); 1317 } 1318 } 1319 1320 autoCreateBlock(); 1321 appendStmt(Block, DS); 1322 1323 if (Init) { 1324 if (HasTemporaries) 1325 // For expression with temporaries go directly to subexpression to omit 1326 // generating destructors for the second time. 1327 Visit(cast<ExprWithCleanups>(Init)->getSubExpr()); 1328 else 1329 Visit(Init); 1330 } 1331 1332 // If the type of VD is a VLA, then we must process its size expressions. 1333 for (const VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); 1334 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1335 Block = addStmt(VA->getSizeExpr()); 1336 1337 // Remove variable from local scope. 1338 if (ScopePos && VD == *ScopePos) 1339 ++ScopePos; 1340 1341 return Block; 1342} 1343 1344CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 1345 // We may see an if statement in the middle of a basic block, or it may be the 1346 // first statement we are processing. In either case, we create a new basic 1347 // block. First, we create the blocks for the then...else statements, and 1348 // then we create the block containing the if statement. If we were in the 1349 // middle of a block, we stop processing that block. That block is then the 1350 // implicit successor for the "then" and "else" clauses. 1351 1352 // Save local scope position because in case of condition variable ScopePos 1353 // won't be restored when traversing AST. 1354 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1355 1356 // Create local scope for possible condition variable. 1357 // Store scope position. Add implicit destructor. 1358 if (VarDecl* VD = I->getConditionVariable()) { 1359 LocalScope::const_iterator BeginScopePos = ScopePos; 1360 addLocalScopeForVarDecl(VD); 1361 addAutomaticObjDtors(ScopePos, BeginScopePos, I); 1362 } 1363 1364 // The block we were proccessing is now finished. Make it the successor 1365 // block. 1366 if (Block) { 1367 Succ = Block; 1368 if (badCFG) 1369 return 0; 1370 } 1371 1372 // Process the false branch. 1373 CFGBlock* ElseBlock = Succ; 1374 1375 if (Stmt* Else = I->getElse()) { 1376 SaveAndRestore<CFGBlock*> sv(Succ); 1377 1378 // NULL out Block so that the recursive call to Visit will 1379 // create a new basic block. 1380 Block = NULL; 1381 1382 // If branch is not a compound statement create implicit scope 1383 // and add destructors. 1384 if (!isa<CompoundStmt>(Else)) 1385 addLocalScopeAndDtors(Else); 1386 1387 ElseBlock = addStmt(Else); 1388 1389 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 1390 ElseBlock = sv.get(); 1391 else if (Block) { 1392 if (badCFG) 1393 return 0; 1394 } 1395 } 1396 1397 // Process the true branch. 1398 CFGBlock* ThenBlock; 1399 { 1400 Stmt* Then = I->getThen(); 1401 assert(Then); 1402 SaveAndRestore<CFGBlock*> sv(Succ); 1403 Block = NULL; 1404 1405 // If branch is not a compound statement create implicit scope 1406 // and add destructors. 1407 if (!isa<CompoundStmt>(Then)) 1408 addLocalScopeAndDtors(Then); 1409 1410 ThenBlock = addStmt(Then); 1411 1412 if (!ThenBlock) { 1413 // We can reach here if the "then" body has all NullStmts. 1414 // Create an empty block so we can distinguish between true and false 1415 // branches in path-sensitive analyses. 1416 ThenBlock = createBlock(false); 1417 addSuccessor(ThenBlock, sv.get()); 1418 } else if (Block) { 1419 if (badCFG) 1420 return 0; 1421 } 1422 } 1423 1424 // Now create a new block containing the if statement. 1425 Block = createBlock(false); 1426 1427 // Set the terminator of the new block to the If statement. 1428 Block->setTerminator(I); 1429 1430 // See if this is a known constant. 1431 const TryResult &KnownVal = tryEvaluateBool(I->getCond()); 1432 1433 // Now add the successors. 1434 addSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 1435 addSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 1436 1437 // Add the condition as the last statement in the new block. This may create 1438 // new blocks as the condition may contain control-flow. Any newly created 1439 // blocks will be pointed to be "Block". 1440 Block = addStmt(I->getCond()); 1441 1442 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 1443 // and the condition variable initialization to the CFG. 1444 if (VarDecl *VD = I->getConditionVariable()) { 1445 if (Expr *Init = VD->getInit()) { 1446 autoCreateBlock(); 1447 appendStmt(Block, I); 1448 addStmt(Init); 1449 } 1450 } 1451 1452 return Block; 1453} 1454 1455 1456CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 1457 // If we were in the middle of a block we stop processing that block. 1458 // 1459 // NOTE: If a "return" appears in the middle of a block, this means that the 1460 // code afterwards is DEAD (unreachable). We still keep a basic block 1461 // for that code; a simple "mark-and-sweep" from the entry block will be 1462 // able to report such dead blocks. 1463 1464 // Create the new block. 1465 Block = createBlock(false); 1466 1467 // The Exit block is the only successor. 1468 addAutomaticObjDtors(ScopePos, LocalScope::const_iterator(), R); 1469 addSuccessor(Block, &cfg->getExit()); 1470 1471 // Add the return statement to the block. This may create new blocks if R 1472 // contains control-flow (short-circuit operations). 1473 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 1474} 1475 1476CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt *L) { 1477 // Get the block of the labeled statement. Add it to our map. 1478 addStmt(L->getSubStmt()); 1479 CFGBlock *LabelBlock = Block; 1480 1481 if (!LabelBlock) // This can happen when the body is empty, i.e. 1482 LabelBlock = createBlock(); // scopes that only contains NullStmts. 1483 1484 assert(LabelMap.find(L->getDecl()) == LabelMap.end() && 1485 "label already in map"); 1486 LabelMap[L->getDecl()] = JumpTarget(LabelBlock, ScopePos); 1487 1488 // Labels partition blocks, so this is the end of the basic block we were 1489 // processing (L is the block's label). Because this is label (and we have 1490 // already processed the substatement) there is no extra control-flow to worry 1491 // about. 1492 LabelBlock->setLabel(L); 1493 if (badCFG) 1494 return 0; 1495 1496 // We set Block to NULL to allow lazy creation of a new block (if necessary); 1497 Block = NULL; 1498 1499 // This block is now the implicit successor of other blocks. 1500 Succ = LabelBlock; 1501 1502 return LabelBlock; 1503} 1504 1505CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 1506 // Goto is a control-flow statement. Thus we stop processing the current 1507 // block and create a new one. 1508 1509 Block = createBlock(false); 1510 Block->setTerminator(G); 1511 1512 // If we already know the mapping to the label block add the successor now. 1513 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 1514 1515 if (I == LabelMap.end()) 1516 // We will need to backpatch this block later. 1517 BackpatchBlocks.push_back(JumpSource(Block, ScopePos)); 1518 else { 1519 JumpTarget JT = I->second; 1520 addAutomaticObjDtors(ScopePos, JT.scopePosition, G); 1521 addSuccessor(Block, JT.block); 1522 } 1523 1524 return Block; 1525} 1526 1527CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 1528 CFGBlock* LoopSuccessor = NULL; 1529 1530 // Save local scope position because in case of condition variable ScopePos 1531 // won't be restored when traversing AST. 1532 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1533 1534 // Create local scope for init statement and possible condition variable. 1535 // Add destructor for init statement and condition variable. 1536 // Store scope position for continue statement. 1537 if (Stmt* Init = F->getInit()) 1538 addLocalScopeForStmt(Init); 1539 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1540 1541 if (VarDecl* VD = F->getConditionVariable()) 1542 addLocalScopeForVarDecl(VD); 1543 LocalScope::const_iterator ContinueScopePos = ScopePos; 1544 1545 addAutomaticObjDtors(ScopePos, save_scope_pos.get(), F); 1546 1547 // "for" is a control-flow statement. Thus we stop processing the current 1548 // block. 1549 if (Block) { 1550 if (badCFG) 1551 return 0; 1552 LoopSuccessor = Block; 1553 } else 1554 LoopSuccessor = Succ; 1555 1556 // Save the current value for the break targets. 1557 // All breaks should go to the code following the loop. 1558 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 1559 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1560 1561 // Because of short-circuit evaluation, the condition of the loop can span 1562 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1563 // evaluate the condition. 1564 CFGBlock* ExitConditionBlock = createBlock(false); 1565 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1566 1567 // Set the terminator for the "exit" condition block. 1568 ExitConditionBlock->setTerminator(F); 1569 1570 // Now add the actual condition to the condition block. Because the condition 1571 // itself may contain control-flow, new blocks may be created. 1572 if (Stmt* C = F->getCond()) { 1573 Block = ExitConditionBlock; 1574 EntryConditionBlock = addStmt(C); 1575 if (badCFG) 1576 return 0; 1577 assert(Block == EntryConditionBlock || 1578 (Block == 0 && EntryConditionBlock == Succ)); 1579 1580 // If this block contains a condition variable, add both the condition 1581 // variable and initializer to the CFG. 1582 if (VarDecl *VD = F->getConditionVariable()) { 1583 if (Expr *Init = VD->getInit()) { 1584 autoCreateBlock(); 1585 appendStmt(Block, F); 1586 EntryConditionBlock = addStmt(Init); 1587 assert(Block == EntryConditionBlock); 1588 } 1589 } 1590 1591 if (Block) { 1592 if (badCFG) 1593 return 0; 1594 } 1595 } 1596 1597 // The condition block is the implicit successor for the loop body as well as 1598 // any code above the loop. 1599 Succ = EntryConditionBlock; 1600 1601 // See if this is a known constant. 1602 TryResult KnownVal(true); 1603 1604 if (F->getCond()) 1605 KnownVal = tryEvaluateBool(F->getCond()); 1606 1607 // Now create the loop body. 1608 { 1609 assert(F->getBody()); 1610 1611 // Save the current values for Block, Succ, and continue targets. 1612 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1613 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget); 1614 1615 // Create a new block to contain the (bottom) of the loop body. 1616 Block = NULL; 1617 1618 // Loop body should end with destructor of Condition variable (if any). 1619 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, F); 1620 1621 if (Stmt* I = F->getInc()) { 1622 // Generate increment code in its own basic block. This is the target of 1623 // continue statements. 1624 Succ = addStmt(I); 1625 } else { 1626 // No increment code. Create a special, empty, block that is used as the 1627 // target block for "looping back" to the start of the loop. 1628 assert(Succ == EntryConditionBlock); 1629 Succ = Block ? Block : createBlock(); 1630 } 1631 1632 // Finish up the increment (or empty) block if it hasn't been already. 1633 if (Block) { 1634 assert(Block == Succ); 1635 if (badCFG) 1636 return 0; 1637 Block = 0; 1638 } 1639 1640 ContinueJumpTarget = JumpTarget(Succ, ContinueScopePos); 1641 1642 // The starting block for the loop increment is the block that should 1643 // represent the 'loop target' for looping back to the start of the loop. 1644 ContinueJumpTarget.block->setLoopTarget(F); 1645 1646 // If body is not a compound statement create implicit scope 1647 // and add destructors. 1648 if (!isa<CompoundStmt>(F->getBody())) 1649 addLocalScopeAndDtors(F->getBody()); 1650 1651 // Now populate the body block, and in the process create new blocks as we 1652 // walk the body of the loop. 1653 CFGBlock* BodyBlock = addStmt(F->getBody()); 1654 1655 if (!BodyBlock) 1656 BodyBlock = ContinueJumpTarget.block;//can happen for "for (...;...;...);" 1657 else if (badCFG) 1658 return 0; 1659 1660 // This new body block is a successor to our "exit" condition block. 1661 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1662 } 1663 1664 // Link up the condition block with the code that follows the loop. (the 1665 // false branch). 1666 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1667 1668 // If the loop contains initialization, create a new block for those 1669 // statements. This block can also contain statements that precede the loop. 1670 if (Stmt* I = F->getInit()) { 1671 Block = createBlock(); 1672 return addStmt(I); 1673 } 1674 1675 // There is no loop initialization. We are thus basically a while loop. 1676 // NULL out Block to force lazy block construction. 1677 Block = NULL; 1678 Succ = EntryConditionBlock; 1679 return EntryConditionBlock; 1680} 1681 1682CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1683 if (asc.alwaysAdd()) { 1684 autoCreateBlock(); 1685 appendStmt(Block, M); 1686 } 1687 return Visit(M->getBase()); 1688} 1689 1690CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1691 // Objective-C fast enumeration 'for' statements: 1692 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1693 // 1694 // for ( Type newVariable in collection_expression ) { statements } 1695 // 1696 // becomes: 1697 // 1698 // prologue: 1699 // 1. collection_expression 1700 // T. jump to loop_entry 1701 // loop_entry: 1702 // 1. side-effects of element expression 1703 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1704 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1705 // TB: 1706 // statements 1707 // T. jump to loop_entry 1708 // FB: 1709 // what comes after 1710 // 1711 // and 1712 // 1713 // Type existingItem; 1714 // for ( existingItem in expression ) { statements } 1715 // 1716 // becomes: 1717 // 1718 // the same with newVariable replaced with existingItem; the binding works 1719 // the same except that for one ObjCForCollectionStmt::getElement() returns 1720 // a DeclStmt and the other returns a DeclRefExpr. 1721 // 1722 1723 CFGBlock* LoopSuccessor = 0; 1724 1725 if (Block) { 1726 if (badCFG) 1727 return 0; 1728 LoopSuccessor = Block; 1729 Block = 0; 1730 } else 1731 LoopSuccessor = Succ; 1732 1733 // Build the condition blocks. 1734 CFGBlock* ExitConditionBlock = createBlock(false); 1735 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1736 1737 // Set the terminator for the "exit" condition block. 1738 ExitConditionBlock->setTerminator(S); 1739 1740 // The last statement in the block should be the ObjCForCollectionStmt, which 1741 // performs the actual binding to 'element' and determines if there are any 1742 // more items in the collection. 1743 appendStmt(ExitConditionBlock, S); 1744 Block = ExitConditionBlock; 1745 1746 // Walk the 'element' expression to see if there are any side-effects. We 1747 // generate new blocks as necesary. We DON'T add the statement by default to 1748 // the CFG unless it contains control-flow. 1749 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1750 if (Block) { 1751 if (badCFG) 1752 return 0; 1753 Block = 0; 1754 } 1755 1756 // The condition block is the implicit successor for the loop body as well as 1757 // any code above the loop. 1758 Succ = EntryConditionBlock; 1759 1760 // Now create the true branch. 1761 { 1762 // Save the current values for Succ, continue and break targets. 1763 SaveAndRestore<CFGBlock*> save_Succ(Succ); 1764 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1765 save_break(BreakJumpTarget); 1766 1767 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1768 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 1769 1770 CFGBlock* BodyBlock = addStmt(S->getBody()); 1771 1772 if (!BodyBlock) 1773 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1774 else if (Block) { 1775 if (badCFG) 1776 return 0; 1777 } 1778 1779 // This new body block is a successor to our "exit" condition block. 1780 addSuccessor(ExitConditionBlock, BodyBlock); 1781 } 1782 1783 // Link up the condition block with the code that follows the loop. 1784 // (the false branch). 1785 addSuccessor(ExitConditionBlock, LoopSuccessor); 1786 1787 // Now create a prologue block to contain the collection expression. 1788 Block = createBlock(); 1789 return addStmt(S->getCollection()); 1790} 1791 1792CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1793 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1794 1795 // Inline the body. 1796 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1797 1798 // The sync body starts its own basic block. This makes it a little easier 1799 // for diagnostic clients. 1800 if (SyncBlock) { 1801 if (badCFG) 1802 return 0; 1803 1804 Block = 0; 1805 Succ = SyncBlock; 1806 } 1807 1808 // Add the @synchronized to the CFG. 1809 autoCreateBlock(); 1810 appendStmt(Block, S); 1811 1812 // Inline the sync expression. 1813 return addStmt(S->getSynchExpr()); 1814} 1815 1816CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1817 // FIXME 1818 return NYS(); 1819} 1820 1821CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1822 CFGBlock* LoopSuccessor = NULL; 1823 1824 // Save local scope position because in case of condition variable ScopePos 1825 // won't be restored when traversing AST. 1826 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 1827 1828 // Create local scope for possible condition variable. 1829 // Store scope position for continue statement. 1830 LocalScope::const_iterator LoopBeginScopePos = ScopePos; 1831 if (VarDecl* VD = W->getConditionVariable()) { 1832 addLocalScopeForVarDecl(VD); 1833 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1834 } 1835 1836 // "while" is a control-flow statement. Thus we stop processing the current 1837 // block. 1838 if (Block) { 1839 if (badCFG) 1840 return 0; 1841 LoopSuccessor = Block; 1842 Block = 0; 1843 } else 1844 LoopSuccessor = Succ; 1845 1846 // Because of short-circuit evaluation, the condition of the loop can span 1847 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1848 // evaluate the condition. 1849 CFGBlock* ExitConditionBlock = createBlock(false); 1850 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1851 1852 // Set the terminator for the "exit" condition block. 1853 ExitConditionBlock->setTerminator(W); 1854 1855 // Now add the actual condition to the condition block. Because the condition 1856 // itself may contain control-flow, new blocks may be created. Thus we update 1857 // "Succ" after adding the condition. 1858 if (Stmt* C = W->getCond()) { 1859 Block = ExitConditionBlock; 1860 EntryConditionBlock = addStmt(C); 1861 // The condition might finish the current 'Block'. 1862 Block = EntryConditionBlock; 1863 1864 // If this block contains a condition variable, add both the condition 1865 // variable and initializer to the CFG. 1866 if (VarDecl *VD = W->getConditionVariable()) { 1867 if (Expr *Init = VD->getInit()) { 1868 autoCreateBlock(); 1869 appendStmt(Block, W); 1870 EntryConditionBlock = addStmt(Init); 1871 assert(Block == EntryConditionBlock); 1872 } 1873 } 1874 1875 if (Block) { 1876 if (badCFG) 1877 return 0; 1878 } 1879 } 1880 1881 // The condition block is the implicit successor for the loop body as well as 1882 // any code above the loop. 1883 Succ = EntryConditionBlock; 1884 1885 // See if this is a known constant. 1886 const TryResult& KnownVal = tryEvaluateBool(W->getCond()); 1887 1888 // Process the loop body. 1889 { 1890 assert(W->getBody()); 1891 1892 // Save the current values for Block, Succ, and continue and break targets 1893 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 1894 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 1895 save_break(BreakJumpTarget); 1896 1897 // Create an empty block to represent the transition block for looping back 1898 // to the head of the loop. 1899 Block = 0; 1900 assert(Succ == EntryConditionBlock); 1901 Succ = createBlock(); 1902 Succ->setLoopTarget(W); 1903 ContinueJumpTarget = JumpTarget(Succ, LoopBeginScopePos); 1904 1905 // All breaks should go to the code following the loop. 1906 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 1907 1908 // NULL out Block to force lazy instantiation of blocks for the body. 1909 Block = NULL; 1910 1911 // Loop body should end with destructor of Condition variable (if any). 1912 addAutomaticObjDtors(ScopePos, LoopBeginScopePos, W); 1913 1914 // If body is not a compound statement create implicit scope 1915 // and add destructors. 1916 if (!isa<CompoundStmt>(W->getBody())) 1917 addLocalScopeAndDtors(W->getBody()); 1918 1919 // Create the body. The returned block is the entry to the loop body. 1920 CFGBlock* BodyBlock = addStmt(W->getBody()); 1921 1922 if (!BodyBlock) 1923 BodyBlock = ContinueJumpTarget.block; // can happen for "while(...) ;" 1924 else if (Block) { 1925 if (badCFG) 1926 return 0; 1927 } 1928 1929 // Add the loop body entry as a successor to the condition. 1930 addSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1931 } 1932 1933 // Link up the condition block with the code that follows the loop. (the 1934 // false branch). 1935 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1936 1937 // There can be no more statements in the condition block since we loop back 1938 // to this block. NULL out Block to force lazy creation of another block. 1939 Block = NULL; 1940 1941 // Return the condition block, which is the dominating block for the loop. 1942 Succ = EntryConditionBlock; 1943 return EntryConditionBlock; 1944} 1945 1946 1947CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1948 // FIXME: For now we pretend that @catch and the code it contains does not 1949 // exit. 1950 return Block; 1951} 1952 1953CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1954 // FIXME: This isn't complete. We basically treat @throw like a return 1955 // statement. 1956 1957 // If we were in the middle of a block we stop processing that block. 1958 if (badCFG) 1959 return 0; 1960 1961 // Create the new block. 1962 Block = createBlock(false); 1963 1964 // The Exit block is the only successor. 1965 addSuccessor(Block, &cfg->getExit()); 1966 1967 // Add the statement to the block. This may create new blocks if S contains 1968 // control-flow (short-circuit operations). 1969 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1970} 1971 1972CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1973 // If we were in the middle of a block we stop processing that block. 1974 if (badCFG) 1975 return 0; 1976 1977 // Create the new block. 1978 Block = createBlock(false); 1979 1980 if (TryTerminatedBlock) 1981 // The current try statement is the only successor. 1982 addSuccessor(Block, TryTerminatedBlock); 1983 else 1984 // otherwise the Exit block is the only successor. 1985 addSuccessor(Block, &cfg->getExit()); 1986 1987 // Add the statement to the block. This may create new blocks if S contains 1988 // control-flow (short-circuit operations). 1989 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1990} 1991 1992CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1993 CFGBlock* LoopSuccessor = NULL; 1994 1995 // "do...while" is a control-flow statement. Thus we stop processing the 1996 // current block. 1997 if (Block) { 1998 if (badCFG) 1999 return 0; 2000 LoopSuccessor = Block; 2001 } else 2002 LoopSuccessor = Succ; 2003 2004 // Because of short-circuit evaluation, the condition of the loop can span 2005 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 2006 // evaluate the condition. 2007 CFGBlock* ExitConditionBlock = createBlock(false); 2008 CFGBlock* EntryConditionBlock = ExitConditionBlock; 2009 2010 // Set the terminator for the "exit" condition block. 2011 ExitConditionBlock->setTerminator(D); 2012 2013 // Now add the actual condition to the condition block. Because the condition 2014 // itself may contain control-flow, new blocks may be created. 2015 if (Stmt* C = D->getCond()) { 2016 Block = ExitConditionBlock; 2017 EntryConditionBlock = addStmt(C); 2018 if (Block) { 2019 if (badCFG) 2020 return 0; 2021 } 2022 } 2023 2024 // The condition block is the implicit successor for the loop body. 2025 Succ = EntryConditionBlock; 2026 2027 // See if this is a known constant. 2028 const TryResult &KnownVal = tryEvaluateBool(D->getCond()); 2029 2030 // Process the loop body. 2031 CFGBlock* BodyBlock = NULL; 2032 { 2033 assert(D->getBody()); 2034 2035 // Save the current values for Block, Succ, and continue and break targets 2036 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ); 2037 SaveAndRestore<JumpTarget> save_continue(ContinueJumpTarget), 2038 save_break(BreakJumpTarget); 2039 2040 // All continues within this loop should go to the condition block 2041 ContinueJumpTarget = JumpTarget(EntryConditionBlock, ScopePos); 2042 2043 // All breaks should go to the code following the loop. 2044 BreakJumpTarget = JumpTarget(LoopSuccessor, ScopePos); 2045 2046 // NULL out Block to force lazy instantiation of blocks for the body. 2047 Block = NULL; 2048 2049 // If body is not a compound statement create implicit scope 2050 // and add destructors. 2051 if (!isa<CompoundStmt>(D->getBody())) 2052 addLocalScopeAndDtors(D->getBody()); 2053 2054 // Create the body. The returned block is the entry to the loop body. 2055 BodyBlock = addStmt(D->getBody()); 2056 2057 if (!BodyBlock) 2058 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 2059 else if (Block) { 2060 if (badCFG) 2061 return 0; 2062 } 2063 2064 if (!KnownVal.isFalse()) { 2065 // Add an intermediate block between the BodyBlock and the 2066 // ExitConditionBlock to represent the "loop back" transition. Create an 2067 // empty block to represent the transition block for looping back to the 2068 // head of the loop. 2069 // FIXME: Can we do this more efficiently without adding another block? 2070 Block = NULL; 2071 Succ = BodyBlock; 2072 CFGBlock *LoopBackBlock = createBlock(); 2073 LoopBackBlock->setLoopTarget(D); 2074 2075 // Add the loop body entry as a successor to the condition. 2076 addSuccessor(ExitConditionBlock, LoopBackBlock); 2077 } 2078 else 2079 addSuccessor(ExitConditionBlock, NULL); 2080 } 2081 2082 // Link up the condition block with the code that follows the loop. 2083 // (the false branch). 2084 addSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 2085 2086 // There can be no more statements in the body block(s) since we loop back to 2087 // the body. NULL out Block to force lazy creation of another block. 2088 Block = NULL; 2089 2090 // Return the loop body, which is the dominating block for the loop. 2091 Succ = BodyBlock; 2092 return BodyBlock; 2093} 2094 2095CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 2096 // "continue" is a control-flow statement. Thus we stop processing the 2097 // current block. 2098 if (badCFG) 2099 return 0; 2100 2101 // Now create a new block that ends with the continue statement. 2102 Block = createBlock(false); 2103 Block->setTerminator(C); 2104 2105 // If there is no target for the continue, then we are looking at an 2106 // incomplete AST. This means the CFG cannot be constructed. 2107 if (ContinueJumpTarget.block) { 2108 addAutomaticObjDtors(ScopePos, ContinueJumpTarget.scopePosition, C); 2109 addSuccessor(Block, ContinueJumpTarget.block); 2110 } else 2111 badCFG = true; 2112 2113 return Block; 2114} 2115 2116CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 2117 AddStmtChoice asc) { 2118 2119 if (asc.alwaysAdd()) { 2120 autoCreateBlock(); 2121 appendStmt(Block, E); 2122 } 2123 2124 // VLA types have expressions that must be evaluated. 2125 if (E->isArgumentType()) { 2126 for (const VariableArrayType *VA =FindVA(E->getArgumentType().getTypePtr()); 2127 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 2128 addStmt(VA->getSizeExpr()); 2129 } 2130 2131 return Block; 2132} 2133 2134/// VisitStmtExpr - Utility method to handle (nested) statement 2135/// expressions (a GCC extension). 2136CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 2137 if (asc.alwaysAdd()) { 2138 autoCreateBlock(); 2139 appendStmt(Block, SE); 2140 } 2141 return VisitCompoundStmt(SE->getSubStmt()); 2142} 2143 2144CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 2145 // "switch" is a control-flow statement. Thus we stop processing the current 2146 // block. 2147 CFGBlock* SwitchSuccessor = NULL; 2148 2149 // Save local scope position because in case of condition variable ScopePos 2150 // won't be restored when traversing AST. 2151 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2152 2153 // Create local scope for possible condition variable. 2154 // Store scope position. Add implicit destructor. 2155 if (VarDecl* VD = Terminator->getConditionVariable()) { 2156 LocalScope::const_iterator SwitchBeginScopePos = ScopePos; 2157 addLocalScopeForVarDecl(VD); 2158 addAutomaticObjDtors(ScopePos, SwitchBeginScopePos, Terminator); 2159 } 2160 2161 if (Block) { 2162 if (badCFG) 2163 return 0; 2164 SwitchSuccessor = Block; 2165 } else SwitchSuccessor = Succ; 2166 2167 // Save the current "switch" context. 2168 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 2169 save_default(DefaultCaseBlock); 2170 SaveAndRestore<JumpTarget> save_break(BreakJumpTarget); 2171 2172 // Set the "default" case to be the block after the switch statement. If the 2173 // switch statement contains a "default:", this value will be overwritten with 2174 // the block for that code. 2175 DefaultCaseBlock = SwitchSuccessor; 2176 2177 // Create a new block that will contain the switch statement. 2178 SwitchTerminatedBlock = createBlock(false); 2179 2180 // Now process the switch body. The code after the switch is the implicit 2181 // successor. 2182 Succ = SwitchSuccessor; 2183 BreakJumpTarget = JumpTarget(SwitchSuccessor, ScopePos); 2184 2185 // When visiting the body, the case statements should automatically get linked 2186 // up to the switch. We also don't keep a pointer to the body, since all 2187 // control-flow from the switch goes to case/default statements. 2188 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 2189 Block = NULL; 2190 2191 // For pruning unreachable case statements, save the current state 2192 // for tracking the condition value. 2193 SaveAndRestore<bool> save_switchExclusivelyCovered(switchExclusivelyCovered, 2194 false); 2195 2196 // Determine if the switch condition can be explicitly evaluated. 2197 assert(Terminator->getCond() && "switch condition must be non-NULL"); 2198 Expr::EvalResult result; 2199 tryEvaluate(Terminator->getCond(), result); 2200 SaveAndRestore<Expr::EvalResult*> save_switchCond(switchCond, &result); 2201 2202 // If body is not a compound statement create implicit scope 2203 // and add destructors. 2204 if (!isa<CompoundStmt>(Terminator->getBody())) 2205 addLocalScopeAndDtors(Terminator->getBody()); 2206 2207 addStmt(Terminator->getBody()); 2208 if (Block) { 2209 if (badCFG) 2210 return 0; 2211 } 2212 2213 // If we have no "default:" case, the default transition is to the code 2214 // following the switch body. 2215 addSuccessor(SwitchTerminatedBlock, 2216 switchExclusivelyCovered ? 0 : DefaultCaseBlock); 2217 2218 // Add the terminator and condition in the switch block. 2219 SwitchTerminatedBlock->setTerminator(Terminator); 2220 Block = SwitchTerminatedBlock; 2221 Block = addStmt(Terminator->getCond()); 2222 2223 // Finally, if the SwitchStmt contains a condition variable, add both the 2224 // SwitchStmt and the condition variable initialization to the CFG. 2225 if (VarDecl *VD = Terminator->getConditionVariable()) { 2226 if (Expr *Init = VD->getInit()) { 2227 autoCreateBlock(); 2228 appendStmt(Block, Terminator); 2229 addStmt(Init); 2230 } 2231 } 2232 2233 return Block; 2234} 2235 2236static bool shouldAddCase(bool &switchExclusivelyCovered, 2237 const Expr::EvalResult &switchCond, 2238 const CaseStmt *CS, 2239 ASTContext &Ctx) { 2240 bool addCase = false; 2241 2242 if (!switchExclusivelyCovered) { 2243 if (switchCond.Val.isInt()) { 2244 // Evaluate the LHS of the case value. 2245 Expr::EvalResult V1; 2246 CS->getLHS()->Evaluate(V1, Ctx); 2247 assert(V1.Val.isInt()); 2248 const llvm::APSInt &condInt = switchCond.Val.getInt(); 2249 const llvm::APSInt &lhsInt = V1.Val.getInt(); 2250 2251 if (condInt == lhsInt) { 2252 addCase = true; 2253 switchExclusivelyCovered = true; 2254 } 2255 else if (condInt < lhsInt) { 2256 if (const Expr *RHS = CS->getRHS()) { 2257 // Evaluate the RHS of the case value. 2258 Expr::EvalResult V2; 2259 RHS->Evaluate(V2, Ctx); 2260 assert(V2.Val.isInt()); 2261 if (V2.Val.getInt() <= condInt) { 2262 addCase = true; 2263 switchExclusivelyCovered = true; 2264 } 2265 } 2266 } 2267 } 2268 else 2269 addCase = true; 2270 } 2271 return addCase; 2272} 2273 2274CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 2275 // CaseStmts are essentially labels, so they are the first statement in a 2276 // block. 2277 CFGBlock *TopBlock = 0, *LastBlock = 0; 2278 assert(switchCond); 2279 2280 if (Stmt *Sub = CS->getSubStmt()) { 2281 // For deeply nested chains of CaseStmts, instead of doing a recursion 2282 // (which can blow out the stack), manually unroll and create blocks 2283 // along the way. 2284 while (isa<CaseStmt>(Sub)) { 2285 CFGBlock *currentBlock = createBlock(false); 2286 currentBlock->setLabel(CS); 2287 2288 if (TopBlock) 2289 addSuccessor(LastBlock, currentBlock); 2290 else 2291 TopBlock = currentBlock; 2292 2293 addSuccessor(SwitchTerminatedBlock, 2294 shouldAddCase(switchExclusivelyCovered, *switchCond, 2295 CS, *Context) 2296 ? currentBlock : 0); 2297 2298 LastBlock = currentBlock; 2299 CS = cast<CaseStmt>(Sub); 2300 Sub = CS->getSubStmt(); 2301 } 2302 2303 addStmt(Sub); 2304 } 2305 2306 CFGBlock* CaseBlock = Block; 2307 if (!CaseBlock) 2308 CaseBlock = createBlock(); 2309 2310 // Cases statements partition blocks, so this is the top of the basic block we 2311 // were processing (the "case XXX:" is the label). 2312 CaseBlock->setLabel(CS); 2313 2314 if (badCFG) 2315 return 0; 2316 2317 // Add this block to the list of successors for the block with the switch 2318 // statement. 2319 assert(SwitchTerminatedBlock); 2320 addSuccessor(SwitchTerminatedBlock, 2321 shouldAddCase(switchExclusivelyCovered, *switchCond, 2322 CS, *Context) 2323 ? CaseBlock : 0); 2324 2325 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2326 Block = NULL; 2327 2328 if (TopBlock) { 2329 addSuccessor(LastBlock, CaseBlock); 2330 Succ = TopBlock; 2331 } else { 2332 // This block is now the implicit successor of other blocks. 2333 Succ = CaseBlock; 2334 } 2335 2336 return Succ; 2337} 2338 2339CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 2340 if (Terminator->getSubStmt()) 2341 addStmt(Terminator->getSubStmt()); 2342 2343 DefaultCaseBlock = Block; 2344 2345 if (!DefaultCaseBlock) 2346 DefaultCaseBlock = createBlock(); 2347 2348 // Default statements partition blocks, so this is the top of the basic block 2349 // we were processing (the "default:" is the label). 2350 DefaultCaseBlock->setLabel(Terminator); 2351 2352 if (badCFG) 2353 return 0; 2354 2355 // Unlike case statements, we don't add the default block to the successors 2356 // for the switch statement immediately. This is done when we finish 2357 // processing the switch statement. This allows for the default case 2358 // (including a fall-through to the code after the switch statement) to always 2359 // be the last successor of a switch-terminated block. 2360 2361 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2362 Block = NULL; 2363 2364 // This block is now the implicit successor of other blocks. 2365 Succ = DefaultCaseBlock; 2366 2367 return DefaultCaseBlock; 2368} 2369 2370CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 2371 // "try"/"catch" is a control-flow statement. Thus we stop processing the 2372 // current block. 2373 CFGBlock* TrySuccessor = NULL; 2374 2375 if (Block) { 2376 if (badCFG) 2377 return 0; 2378 TrySuccessor = Block; 2379 } else TrySuccessor = Succ; 2380 2381 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 2382 2383 // Create a new block that will contain the try statement. 2384 CFGBlock *NewTryTerminatedBlock = createBlock(false); 2385 // Add the terminator in the try block. 2386 NewTryTerminatedBlock->setTerminator(Terminator); 2387 2388 bool HasCatchAll = false; 2389 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 2390 // The code after the try is the implicit successor. 2391 Succ = TrySuccessor; 2392 CXXCatchStmt *CS = Terminator->getHandler(h); 2393 if (CS->getExceptionDecl() == 0) { 2394 HasCatchAll = true; 2395 } 2396 Block = NULL; 2397 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 2398 if (CatchBlock == 0) 2399 return 0; 2400 // Add this block to the list of successors for the block with the try 2401 // statement. 2402 addSuccessor(NewTryTerminatedBlock, CatchBlock); 2403 } 2404 if (!HasCatchAll) { 2405 if (PrevTryTerminatedBlock) 2406 addSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 2407 else 2408 addSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 2409 } 2410 2411 // The code after the try is the implicit successor. 2412 Succ = TrySuccessor; 2413 2414 // Save the current "try" context. 2415 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 2416 TryTerminatedBlock = NewTryTerminatedBlock; 2417 2418 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 2419 Block = NULL; 2420 Block = addStmt(Terminator->getTryBlock()); 2421 return Block; 2422} 2423 2424CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 2425 // CXXCatchStmt are treated like labels, so they are the first statement in a 2426 // block. 2427 2428 // Save local scope position because in case of exception variable ScopePos 2429 // won't be restored when traversing AST. 2430 SaveAndRestore<LocalScope::const_iterator> save_scope_pos(ScopePos); 2431 2432 // Create local scope for possible exception variable. 2433 // Store scope position. Add implicit destructor. 2434 if (VarDecl* VD = CS->getExceptionDecl()) { 2435 LocalScope::const_iterator BeginScopePos = ScopePos; 2436 addLocalScopeForVarDecl(VD); 2437 addAutomaticObjDtors(ScopePos, BeginScopePos, CS); 2438 } 2439 2440 if (CS->getHandlerBlock()) 2441 addStmt(CS->getHandlerBlock()); 2442 2443 CFGBlock* CatchBlock = Block; 2444 if (!CatchBlock) 2445 CatchBlock = createBlock(); 2446 2447 CatchBlock->setLabel(CS); 2448 2449 if (badCFG) 2450 return 0; 2451 2452 // We set Block to NULL to allow lazy creation of a new block (if necessary) 2453 Block = NULL; 2454 2455 return CatchBlock; 2456} 2457 2458CFGBlock *CFGBuilder::VisitExprWithCleanups(ExprWithCleanups *E, 2459 AddStmtChoice asc) { 2460 if (BuildOpts.AddImplicitDtors) { 2461 // If adding implicit destructors visit the full expression for adding 2462 // destructors of temporaries. 2463 VisitForTemporaryDtors(E->getSubExpr()); 2464 2465 // Full expression has to be added as CFGStmt so it will be sequenced 2466 // before destructors of it's temporaries. 2467 asc = asc.withAlwaysAdd(true); 2468 } 2469 return Visit(E->getSubExpr(), asc); 2470} 2471 2472CFGBlock *CFGBuilder::VisitCXXBindTemporaryExpr(CXXBindTemporaryExpr *E, 2473 AddStmtChoice asc) { 2474 if (asc.alwaysAdd()) { 2475 autoCreateBlock(); 2476 appendStmt(Block, E); 2477 2478 // We do not want to propagate the AlwaysAdd property. 2479 asc = asc.withAlwaysAdd(false); 2480 } 2481 return Visit(E->getSubExpr(), asc); 2482} 2483 2484CFGBlock *CFGBuilder::VisitCXXConstructExpr(CXXConstructExpr *C, 2485 AddStmtChoice asc) { 2486 autoCreateBlock(); 2487 if (!C->isElidable()) 2488 appendStmt(Block, C); 2489 2490 return VisitChildren(C); 2491} 2492 2493CFGBlock *CFGBuilder::VisitCXXFunctionalCastExpr(CXXFunctionalCastExpr *E, 2494 AddStmtChoice asc) { 2495 if (asc.alwaysAdd()) { 2496 autoCreateBlock(); 2497 appendStmt(Block, E); 2498 // We do not want to propagate the AlwaysAdd property. 2499 asc = asc.withAlwaysAdd(false); 2500 } 2501 return Visit(E->getSubExpr(), asc); 2502} 2503 2504CFGBlock *CFGBuilder::VisitCXXTemporaryObjectExpr(CXXTemporaryObjectExpr *C, 2505 AddStmtChoice asc) { 2506 autoCreateBlock(); 2507 appendStmt(Block, C); 2508 return VisitChildren(C); 2509} 2510 2511CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 2512 AddStmtChoice asc) { 2513 autoCreateBlock(); 2514 appendStmt(Block, C); 2515 return VisitChildren(C); 2516} 2517 2518CFGBlock *CFGBuilder::VisitImplicitCastExpr(ImplicitCastExpr *E, 2519 AddStmtChoice asc) { 2520 if (asc.alwaysAdd()) { 2521 autoCreateBlock(); 2522 appendStmt(Block, E); 2523 } 2524 return Visit(E->getSubExpr(), AddStmtChoice()); 2525} 2526 2527CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2528 // Lazily create the indirect-goto dispatch block if there isn't one already. 2529 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 2530 2531 if (!IBlock) { 2532 IBlock = createBlock(false); 2533 cfg->setIndirectGotoBlock(IBlock); 2534 } 2535 2536 // IndirectGoto is a control-flow statement. Thus we stop processing the 2537 // current block and create a new one. 2538 if (badCFG) 2539 return 0; 2540 2541 Block = createBlock(false); 2542 Block->setTerminator(I); 2543 addSuccessor(Block, IBlock); 2544 return addStmt(I->getTarget()); 2545} 2546 2547CFGBlock *CFGBuilder::VisitForTemporaryDtors(Stmt *E, bool BindToTemporary) { 2548tryAgain: 2549 if (!E) { 2550 badCFG = true; 2551 return NULL; 2552 } 2553 switch (E->getStmtClass()) { 2554 default: 2555 return VisitChildrenForTemporaryDtors(E); 2556 2557 case Stmt::BinaryOperatorClass: 2558 return VisitBinaryOperatorForTemporaryDtors(cast<BinaryOperator>(E)); 2559 2560 case Stmt::CXXBindTemporaryExprClass: 2561 return VisitCXXBindTemporaryExprForTemporaryDtors( 2562 cast<CXXBindTemporaryExpr>(E), BindToTemporary); 2563 2564 case Stmt::BinaryConditionalOperatorClass: 2565 case Stmt::ConditionalOperatorClass: 2566 return VisitConditionalOperatorForTemporaryDtors( 2567 cast<AbstractConditionalOperator>(E), BindToTemporary); 2568 2569 case Stmt::ImplicitCastExprClass: 2570 // For implicit cast we want BindToTemporary to be passed further. 2571 E = cast<CastExpr>(E)->getSubExpr(); 2572 goto tryAgain; 2573 2574 case Stmt::ParenExprClass: 2575 E = cast<ParenExpr>(E)->getSubExpr(); 2576 goto tryAgain; 2577 } 2578} 2579 2580CFGBlock *CFGBuilder::VisitChildrenForTemporaryDtors(Stmt *E) { 2581 // When visiting children for destructors we want to visit them in reverse 2582 // order. Because there's no reverse iterator for children must to reverse 2583 // them in helper vector. 2584 typedef llvm::SmallVector<Stmt *, 4> ChildrenVect; 2585 ChildrenVect ChildrenRev; 2586 for (Stmt::child_range I = E->children(); I; ++I) { 2587 if (*I) ChildrenRev.push_back(*I); 2588 } 2589 2590 CFGBlock *B = Block; 2591 for (ChildrenVect::reverse_iterator I = ChildrenRev.rbegin(), 2592 L = ChildrenRev.rend(); I != L; ++I) { 2593 if (CFGBlock *R = VisitForTemporaryDtors(*I)) 2594 B = R; 2595 } 2596 return B; 2597} 2598 2599CFGBlock *CFGBuilder::VisitBinaryOperatorForTemporaryDtors(BinaryOperator *E) { 2600 if (E->isLogicalOp()) { 2601 // Destructors for temporaries in LHS expression should be called after 2602 // those for RHS expression. Even if this will unnecessarily create a block, 2603 // this block will be used at least by the full expression. 2604 autoCreateBlock(); 2605 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getLHS()); 2606 if (badCFG) 2607 return NULL; 2608 2609 Succ = ConfluenceBlock; 2610 Block = NULL; 2611 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2612 2613 if (RHSBlock) { 2614 if (badCFG) 2615 return NULL; 2616 2617 // If RHS expression did produce destructors we need to connect created 2618 // blocks to CFG in same manner as for binary operator itself. 2619 CFGBlock *LHSBlock = createBlock(false); 2620 LHSBlock->setTerminator(CFGTerminator(E, true)); 2621 2622 // For binary operator LHS block is before RHS in list of predecessors 2623 // of ConfluenceBlock. 2624 std::reverse(ConfluenceBlock->pred_begin(), 2625 ConfluenceBlock->pred_end()); 2626 2627 // See if this is a known constant. 2628 TryResult KnownVal = tryEvaluateBool(E->getLHS()); 2629 if (KnownVal.isKnown() && (E->getOpcode() == BO_LOr)) 2630 KnownVal.negate(); 2631 2632 // Link LHSBlock with RHSBlock exactly the same way as for binary operator 2633 // itself. 2634 if (E->getOpcode() == BO_LOr) { 2635 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2636 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2637 } else { 2638 assert (E->getOpcode() == BO_LAnd); 2639 addSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 2640 addSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 2641 } 2642 2643 Block = LHSBlock; 2644 return LHSBlock; 2645 } 2646 2647 Block = ConfluenceBlock; 2648 return ConfluenceBlock; 2649 } 2650 2651 if (E->isAssignmentOp()) { 2652 // For assignment operator (=) LHS expression is visited 2653 // before RHS expression. For destructors visit them in reverse order. 2654 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2655 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2656 return LHSBlock ? LHSBlock : RHSBlock; 2657 } 2658 2659 // For any other binary operator RHS expression is visited before 2660 // LHS expression (order of children). For destructors visit them in reverse 2661 // order. 2662 CFGBlock *LHSBlock = VisitForTemporaryDtors(E->getLHS()); 2663 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getRHS()); 2664 return RHSBlock ? RHSBlock : LHSBlock; 2665} 2666 2667CFGBlock *CFGBuilder::VisitCXXBindTemporaryExprForTemporaryDtors( 2668 CXXBindTemporaryExpr *E, bool BindToTemporary) { 2669 // First add destructors for temporaries in subexpression. 2670 CFGBlock *B = VisitForTemporaryDtors(E->getSubExpr()); 2671 if (!BindToTemporary) { 2672 // If lifetime of temporary is not prolonged (by assigning to constant 2673 // reference) add destructor for it. 2674 autoCreateBlock(); 2675 appendTemporaryDtor(Block, E); 2676 B = Block; 2677 } 2678 return B; 2679} 2680 2681CFGBlock *CFGBuilder::VisitConditionalOperatorForTemporaryDtors( 2682 AbstractConditionalOperator *E, bool BindToTemporary) { 2683 // First add destructors for condition expression. Even if this will 2684 // unnecessarily create a block, this block will be used at least by the full 2685 // expression. 2686 autoCreateBlock(); 2687 CFGBlock *ConfluenceBlock = VisitForTemporaryDtors(E->getCond()); 2688 if (badCFG) 2689 return NULL; 2690 if (BinaryConditionalOperator *BCO 2691 = dyn_cast<BinaryConditionalOperator>(E)) { 2692 ConfluenceBlock = VisitForTemporaryDtors(BCO->getCommon()); 2693 if (badCFG) 2694 return NULL; 2695 } 2696 2697 // Try to add block with destructors for LHS expression. 2698 CFGBlock *LHSBlock = NULL; 2699 Succ = ConfluenceBlock; 2700 Block = NULL; 2701 LHSBlock = VisitForTemporaryDtors(E->getTrueExpr(), BindToTemporary); 2702 if (badCFG) 2703 return NULL; 2704 2705 // Try to add block with destructors for RHS expression; 2706 Succ = ConfluenceBlock; 2707 Block = NULL; 2708 CFGBlock *RHSBlock = VisitForTemporaryDtors(E->getFalseExpr(), 2709 BindToTemporary); 2710 if (badCFG) 2711 return NULL; 2712 2713 if (!RHSBlock && !LHSBlock) { 2714 // If neither LHS nor RHS expression had temporaries to destroy don't create 2715 // more blocks. 2716 Block = ConfluenceBlock; 2717 return Block; 2718 } 2719 2720 Block = createBlock(false); 2721 Block->setTerminator(CFGTerminator(E, true)); 2722 2723 // See if this is a known constant. 2724 const TryResult &KnownVal = tryEvaluateBool(E->getCond()); 2725 2726 if (LHSBlock) { 2727 addSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 2728 } else if (KnownVal.isFalse()) { 2729 addSuccessor(Block, NULL); 2730 } else { 2731 addSuccessor(Block, ConfluenceBlock); 2732 std::reverse(ConfluenceBlock->pred_begin(), ConfluenceBlock->pred_end()); 2733 } 2734 2735 if (!RHSBlock) 2736 RHSBlock = ConfluenceBlock; 2737 addSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 2738 2739 return Block; 2740} 2741 2742} // end anonymous namespace 2743 2744/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 2745/// no successors or predecessors. If this is the first block created in the 2746/// CFG, it is automatically set to be the Entry and Exit of the CFG. 2747CFGBlock* CFG::createBlock() { 2748 bool first_block = begin() == end(); 2749 2750 // Create the block. 2751 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 2752 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 2753 Blocks.push_back(Mem, BlkBVC); 2754 2755 // If this is the first block, set it as the Entry and Exit. 2756 if (first_block) 2757 Entry = Exit = &back(); 2758 2759 // Return the block. 2760 return &back(); 2761} 2762 2763/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 2764/// CFG is returned to the caller. 2765CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 2766 const BuildOptions &BO) { 2767 CFGBuilder Builder(C, BO); 2768 return Builder.buildCFG(D, Statement); 2769} 2770 2771const CXXDestructorDecl * 2772CFGImplicitDtor::getDestructorDecl(ASTContext &astContext) const { 2773 switch (getKind()) { 2774 case CFGElement::Invalid: 2775 case CFGElement::Statement: 2776 case CFGElement::Initializer: 2777 llvm_unreachable("getDestructorDecl should only be used with " 2778 "ImplicitDtors"); 2779 case CFGElement::AutomaticObjectDtor: { 2780 const VarDecl *var = cast<CFGAutomaticObjDtor>(this)->getVarDecl(); 2781 QualType ty = var->getType(); 2782 ty = ty.getNonReferenceType(); 2783 if (const ArrayType *arrayType = astContext.getAsArrayType(ty)) { 2784 ty = arrayType->getElementType(); 2785 } 2786 const RecordType *recordType = ty->getAs<RecordType>(); 2787 const CXXRecordDecl *classDecl = 2788 cast<CXXRecordDecl>(recordType->getDecl()); 2789 return classDecl->getDestructor(); 2790 } 2791 case CFGElement::TemporaryDtor: { 2792 const CXXBindTemporaryExpr *bindExpr = 2793 cast<CFGTemporaryDtor>(this)->getBindTemporaryExpr(); 2794 const CXXTemporary *temp = bindExpr->getTemporary(); 2795 return temp->getDestructor(); 2796 } 2797 case CFGElement::BaseDtor: 2798 case CFGElement::MemberDtor: 2799 2800 // Not yet supported. 2801 return 0; 2802 } 2803 llvm_unreachable("getKind() returned bogus value"); 2804 return 0; 2805} 2806 2807bool CFGImplicitDtor::isNoReturn(ASTContext &astContext) const { 2808 if (const CXXDestructorDecl *cdecl = getDestructorDecl(astContext)) { 2809 QualType ty = cdecl->getType(); 2810 return cast<FunctionType>(ty)->getNoReturnAttr(); 2811 } 2812 return false; 2813} 2814 2815//===----------------------------------------------------------------------===// 2816// CFG: Queries for BlkExprs. 2817//===----------------------------------------------------------------------===// 2818 2819namespace { 2820 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 2821} 2822 2823static void FindSubExprAssignments(Stmt *S, 2824 llvm::SmallPtrSet<Expr*,50>& Set) { 2825 if (!S) 2826 return; 2827 2828 for (Stmt::child_range I = S->children(); I; ++I) { 2829 Stmt *child = *I; 2830 if (!child) 2831 continue; 2832 2833 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 2834 if (B->isAssignmentOp()) Set.insert(B); 2835 2836 FindSubExprAssignments(child, Set); 2837 } 2838} 2839 2840static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 2841 BlkExprMapTy* M = new BlkExprMapTy(); 2842 2843 // Look for assignments that are used as subexpressions. These are the only 2844 // assignments that we want to *possibly* register as a block-level 2845 // expression. Basically, if an assignment occurs both in a subexpression and 2846 // at the block-level, it is a block-level expression. 2847 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 2848 2849 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 2850 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 2851 if (const CFGStmt *S = BI->getAs<CFGStmt>()) 2852 FindSubExprAssignments(S->getStmt(), SubExprAssignments); 2853 2854 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 2855 2856 // Iterate over the statements again on identify the Expr* and Stmt* at the 2857 // block-level that are block-level expressions. 2858 2859 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) { 2860 const CFGStmt *CS = BI->getAs<CFGStmt>(); 2861 if (!CS) 2862 continue; 2863 if (Expr* Exp = dyn_cast<Expr>(CS->getStmt())) { 2864 2865 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 2866 // Assignment expressions that are not nested within another 2867 // expression are really "statements" whose value is never used by 2868 // another expression. 2869 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 2870 continue; 2871 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 2872 // Special handling for statement expressions. The last statement in 2873 // the statement expression is also a block-level expr. 2874 const CompoundStmt* C = Terminator->getSubStmt(); 2875 if (!C->body_empty()) { 2876 unsigned x = M->size(); 2877 (*M)[C->body_back()] = x; 2878 } 2879 } 2880 2881 unsigned x = M->size(); 2882 (*M)[Exp] = x; 2883 } 2884 } 2885 2886 // Look at terminators. The condition is a block-level expression. 2887 2888 Stmt* S = (*I)->getTerminatorCondition(); 2889 2890 if (S && M->find(S) == M->end()) { 2891 unsigned x = M->size(); 2892 (*M)[S] = x; 2893 } 2894 } 2895 2896 return M; 2897} 2898 2899CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 2900 assert(S != NULL); 2901 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 2902 2903 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 2904 BlkExprMapTy::iterator I = M->find(S); 2905 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 2906} 2907 2908unsigned CFG::getNumBlkExprs() { 2909 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 2910 return M->size(); 2911 2912 // We assume callers interested in the number of BlkExprs will want 2913 // the map constructed if it doesn't already exist. 2914 BlkExprMap = (void*) PopulateBlkExprMap(*this); 2915 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 2916} 2917 2918//===----------------------------------------------------------------------===// 2919// Filtered walking of the CFG. 2920//===----------------------------------------------------------------------===// 2921 2922bool CFGBlock::FilterEdge(const CFGBlock::FilterOptions &F, 2923 const CFGBlock *From, const CFGBlock *To) { 2924 2925 if (To && F.IgnoreDefaultsWithCoveredEnums) { 2926 // If the 'To' has no label or is labeled but the label isn't a 2927 // CaseStmt then filter this edge. 2928 if (const SwitchStmt *S = 2929 dyn_cast_or_null<SwitchStmt>(From->getTerminator().getStmt())) { 2930 if (S->isAllEnumCasesCovered()) { 2931 const Stmt *L = To->getLabel(); 2932 if (!L || !isa<CaseStmt>(L)) 2933 return true; 2934 } 2935 } 2936 } 2937 2938 return false; 2939} 2940 2941//===----------------------------------------------------------------------===// 2942// Cleanup: CFG dstor. 2943//===----------------------------------------------------------------------===// 2944 2945CFG::~CFG() { 2946 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 2947} 2948 2949//===----------------------------------------------------------------------===// 2950// CFG pretty printing 2951//===----------------------------------------------------------------------===// 2952 2953namespace { 2954 2955class StmtPrinterHelper : public PrinterHelper { 2956 typedef llvm::DenseMap<const Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 2957 typedef llvm::DenseMap<const Decl*,std::pair<unsigned,unsigned> > DeclMapTy; 2958 StmtMapTy StmtMap; 2959 DeclMapTy DeclMap; 2960 signed currentBlock; 2961 unsigned currentStmt; 2962 const LangOptions &LangOpts; 2963public: 2964 2965 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 2966 : currentBlock(0), currentStmt(0), LangOpts(LO) 2967 { 2968 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 2969 unsigned j = 1; 2970 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 2971 BI != BEnd; ++BI, ++j ) { 2972 if (const CFGStmt *SE = BI->getAs<CFGStmt>()) { 2973 const Stmt *stmt= SE->getStmt(); 2974 std::pair<unsigned, unsigned> P((*I)->getBlockID(), j); 2975 StmtMap[stmt] = P; 2976 2977 switch (stmt->getStmtClass()) { 2978 case Stmt::DeclStmtClass: 2979 DeclMap[cast<DeclStmt>(stmt)->getSingleDecl()] = P; 2980 break; 2981 case Stmt::IfStmtClass: { 2982 const VarDecl *var = cast<IfStmt>(stmt)->getConditionVariable(); 2983 if (var) 2984 DeclMap[var] = P; 2985 break; 2986 } 2987 case Stmt::ForStmtClass: { 2988 const VarDecl *var = cast<ForStmt>(stmt)->getConditionVariable(); 2989 if (var) 2990 DeclMap[var] = P; 2991 break; 2992 } 2993 case Stmt::WhileStmtClass: { 2994 const VarDecl *var = 2995 cast<WhileStmt>(stmt)->getConditionVariable(); 2996 if (var) 2997 DeclMap[var] = P; 2998 break; 2999 } 3000 case Stmt::SwitchStmtClass: { 3001 const VarDecl *var = 3002 cast<SwitchStmt>(stmt)->getConditionVariable(); 3003 if (var) 3004 DeclMap[var] = P; 3005 break; 3006 } 3007 case Stmt::CXXCatchStmtClass: { 3008 const VarDecl *var = 3009 cast<CXXCatchStmt>(stmt)->getExceptionDecl(); 3010 if (var) 3011 DeclMap[var] = P; 3012 break; 3013 } 3014 default: 3015 break; 3016 } 3017 } 3018 } 3019 } 3020 } 3021 3022 3023 virtual ~StmtPrinterHelper() {} 3024 3025 const LangOptions &getLangOpts() const { return LangOpts; } 3026 void setBlockID(signed i) { currentBlock = i; } 3027 void setStmtID(unsigned i) { currentStmt = i; } 3028 3029 virtual bool handledStmt(Stmt* S, llvm::raw_ostream& OS) { 3030 StmtMapTy::iterator I = StmtMap.find(S); 3031 3032 if (I == StmtMap.end()) 3033 return false; 3034 3035 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3036 && I->second.second == currentStmt) { 3037 return false; 3038 } 3039 3040 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3041 return true; 3042 } 3043 3044 bool handleDecl(const Decl* D, llvm::raw_ostream& OS) { 3045 DeclMapTy::iterator I = DeclMap.find(D); 3046 3047 if (I == DeclMap.end()) 3048 return false; 3049 3050 if (currentBlock >= 0 && I->second.first == (unsigned) currentBlock 3051 && I->second.second == currentStmt) { 3052 return false; 3053 } 3054 3055 OS << "[B" << I->second.first << "." << I->second.second << "]"; 3056 return true; 3057 } 3058}; 3059} // end anonymous namespace 3060 3061 3062namespace { 3063class CFGBlockTerminatorPrint 3064 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 3065 3066 llvm::raw_ostream& OS; 3067 StmtPrinterHelper* Helper; 3068 PrintingPolicy Policy; 3069public: 3070 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 3071 const PrintingPolicy &Policy) 3072 : OS(os), Helper(helper), Policy(Policy) {} 3073 3074 void VisitIfStmt(IfStmt* I) { 3075 OS << "if "; 3076 I->getCond()->printPretty(OS,Helper,Policy); 3077 } 3078 3079 // Default case. 3080 void VisitStmt(Stmt* Terminator) { 3081 Terminator->printPretty(OS, Helper, Policy); 3082 } 3083 3084 void VisitForStmt(ForStmt* F) { 3085 OS << "for (" ; 3086 if (F->getInit()) 3087 OS << "..."; 3088 OS << "; "; 3089 if (Stmt* C = F->getCond()) 3090 C->printPretty(OS, Helper, Policy); 3091 OS << "; "; 3092 if (F->getInc()) 3093 OS << "..."; 3094 OS << ")"; 3095 } 3096 3097 void VisitWhileStmt(WhileStmt* W) { 3098 OS << "while " ; 3099 if (Stmt* C = W->getCond()) 3100 C->printPretty(OS, Helper, Policy); 3101 } 3102 3103 void VisitDoStmt(DoStmt* D) { 3104 OS << "do ... while "; 3105 if (Stmt* C = D->getCond()) 3106 C->printPretty(OS, Helper, Policy); 3107 } 3108 3109 void VisitSwitchStmt(SwitchStmt* Terminator) { 3110 OS << "switch "; 3111 Terminator->getCond()->printPretty(OS, Helper, Policy); 3112 } 3113 3114 void VisitCXXTryStmt(CXXTryStmt* CS) { 3115 OS << "try ..."; 3116 } 3117 3118 void VisitAbstractConditionalOperator(AbstractConditionalOperator* C) { 3119 C->getCond()->printPretty(OS, Helper, Policy); 3120 OS << " ? ... : ..."; 3121 } 3122 3123 void VisitChooseExpr(ChooseExpr* C) { 3124 OS << "__builtin_choose_expr( "; 3125 C->getCond()->printPretty(OS, Helper, Policy); 3126 OS << " )"; 3127 } 3128 3129 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 3130 OS << "goto *"; 3131 I->getTarget()->printPretty(OS, Helper, Policy); 3132 } 3133 3134 void VisitBinaryOperator(BinaryOperator* B) { 3135 if (!B->isLogicalOp()) { 3136 VisitExpr(B); 3137 return; 3138 } 3139 3140 B->getLHS()->printPretty(OS, Helper, Policy); 3141 3142 switch (B->getOpcode()) { 3143 case BO_LOr: 3144 OS << " || ..."; 3145 return; 3146 case BO_LAnd: 3147 OS << " && ..."; 3148 return; 3149 default: 3150 assert(false && "Invalid logical operator."); 3151 } 3152 } 3153 3154 void VisitExpr(Expr* E) { 3155 E->printPretty(OS, Helper, Policy); 3156 } 3157}; 3158} // end anonymous namespace 3159 3160static void print_elem(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 3161 const CFGElement &E) { 3162 if (const CFGStmt *CS = E.getAs<CFGStmt>()) { 3163 Stmt *S = CS->getStmt(); 3164 3165 if (Helper) { 3166 3167 // special printing for statement-expressions. 3168 if (StmtExpr* SE = dyn_cast<StmtExpr>(S)) { 3169 CompoundStmt* Sub = SE->getSubStmt(); 3170 3171 if (Sub->children()) { 3172 OS << "({ ... ; "; 3173 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 3174 OS << " })\n"; 3175 return; 3176 } 3177 } 3178 // special printing for comma expressions. 3179 if (BinaryOperator* B = dyn_cast<BinaryOperator>(S)) { 3180 if (B->getOpcode() == BO_Comma) { 3181 OS << "... , "; 3182 Helper->handledStmt(B->getRHS(),OS); 3183 OS << '\n'; 3184 return; 3185 } 3186 } 3187 } 3188 S->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3189 3190 if (isa<CXXOperatorCallExpr>(S)) { 3191 OS << " (OperatorCall)"; 3192 } else if (isa<CXXBindTemporaryExpr>(S)) { 3193 OS << " (BindTemporary)"; 3194 } 3195 3196 // Expressions need a newline. 3197 if (isa<Expr>(S)) 3198 OS << '\n'; 3199 3200 } else if (const CFGInitializer *IE = E.getAs<CFGInitializer>()) { 3201 const CXXCtorInitializer *I = IE->getInitializer(); 3202 if (I->isBaseInitializer()) 3203 OS << I->getBaseClass()->getAsCXXRecordDecl()->getName(); 3204 else OS << I->getAnyMember()->getName(); 3205 3206 OS << "("; 3207 if (Expr* IE = I->getInit()) 3208 IE->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 3209 OS << ")"; 3210 3211 if (I->isBaseInitializer()) 3212 OS << " (Base initializer)\n"; 3213 else OS << " (Member initializer)\n"; 3214 3215 } else if (const CFGAutomaticObjDtor *DE = E.getAs<CFGAutomaticObjDtor>()){ 3216 const VarDecl* VD = DE->getVarDecl(); 3217 Helper->handleDecl(VD, OS); 3218 3219 const Type* T = VD->getType().getTypePtr(); 3220 if (const ReferenceType* RT = T->getAs<ReferenceType>()) 3221 T = RT->getPointeeType().getTypePtr(); 3222 else if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3223 T = ET; 3224 3225 OS << ".~" << T->getAsCXXRecordDecl()->getName().str() << "()"; 3226 OS << " (Implicit destructor)\n"; 3227 3228 } else if (const CFGBaseDtor *BE = E.getAs<CFGBaseDtor>()) { 3229 const CXXBaseSpecifier *BS = BE->getBaseSpecifier(); 3230 OS << "~" << BS->getType()->getAsCXXRecordDecl()->getName() << "()"; 3231 OS << " (Base object destructor)\n"; 3232 3233 } else if (const CFGMemberDtor *ME = E.getAs<CFGMemberDtor>()) { 3234 const FieldDecl *FD = ME->getFieldDecl(); 3235 3236 const Type *T = FD->getType().getTypePtr(); 3237 if (const Type *ET = T->getArrayElementTypeNoTypeQual()) 3238 T = ET; 3239 3240 OS << "this->" << FD->getName(); 3241 OS << ".~" << T->getAsCXXRecordDecl()->getName() << "()"; 3242 OS << " (Member object destructor)\n"; 3243 3244 } else if (const CFGTemporaryDtor *TE = E.getAs<CFGTemporaryDtor>()) { 3245 const CXXBindTemporaryExpr *BT = TE->getBindTemporaryExpr(); 3246 OS << "~" << BT->getType()->getAsCXXRecordDecl()->getName() << "()"; 3247 OS << " (Temporary object destructor)\n"; 3248 } 3249} 3250 3251static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 3252 const CFGBlock& B, 3253 StmtPrinterHelper* Helper, bool print_edges) { 3254 3255 if (Helper) Helper->setBlockID(B.getBlockID()); 3256 3257 // Print the header. 3258 OS << "\n [ B" << B.getBlockID(); 3259 3260 if (&B == &cfg->getEntry()) 3261 OS << " (ENTRY) ]\n"; 3262 else if (&B == &cfg->getExit()) 3263 OS << " (EXIT) ]\n"; 3264 else if (&B == cfg->getIndirectGotoBlock()) 3265 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 3266 else 3267 OS << " ]\n"; 3268 3269 // Print the label of this block. 3270 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 3271 3272 if (print_edges) 3273 OS << " "; 3274 3275 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 3276 OS << L->getName(); 3277 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 3278 OS << "case "; 3279 C->getLHS()->printPretty(OS, Helper, 3280 PrintingPolicy(Helper->getLangOpts())); 3281 if (C->getRHS()) { 3282 OS << " ... "; 3283 C->getRHS()->printPretty(OS, Helper, 3284 PrintingPolicy(Helper->getLangOpts())); 3285 } 3286 } else if (isa<DefaultStmt>(Label)) 3287 OS << "default"; 3288 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 3289 OS << "catch ("; 3290 if (CS->getExceptionDecl()) 3291 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 3292 0); 3293 else 3294 OS << "..."; 3295 OS << ")"; 3296 3297 } else 3298 assert(false && "Invalid label statement in CFGBlock."); 3299 3300 OS << ":\n"; 3301 } 3302 3303 // Iterate through the statements in the block and print them. 3304 unsigned j = 1; 3305 3306 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 3307 I != E ; ++I, ++j ) { 3308 3309 // Print the statement # in the basic block and the statement itself. 3310 if (print_edges) 3311 OS << " "; 3312 3313 OS << llvm::format("%3d", j) << ": "; 3314 3315 if (Helper) 3316 Helper->setStmtID(j); 3317 3318 print_elem(OS,Helper,*I); 3319 } 3320 3321 // Print the terminator of this block. 3322 if (B.getTerminator()) { 3323 if (print_edges) 3324 OS << " "; 3325 3326 OS << " T: "; 3327 3328 if (Helper) Helper->setBlockID(-1); 3329 3330 CFGBlockTerminatorPrint TPrinter(OS, Helper, 3331 PrintingPolicy(Helper->getLangOpts())); 3332 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator().getStmt())); 3333 OS << '\n'; 3334 } 3335 3336 if (print_edges) { 3337 // Print the predecessors of this block. 3338 OS << " Predecessors (" << B.pred_size() << "):"; 3339 unsigned i = 0; 3340 3341 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 3342 I != E; ++I, ++i) { 3343 3344 if (i == 8 || (i-8) == 0) 3345 OS << "\n "; 3346 3347 OS << " B" << (*I)->getBlockID(); 3348 } 3349 3350 OS << '\n'; 3351 3352 // Print the successors of this block. 3353 OS << " Successors (" << B.succ_size() << "):"; 3354 i = 0; 3355 3356 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 3357 I != E; ++I, ++i) { 3358 3359 if (i == 8 || (i-8) % 10 == 0) 3360 OS << "\n "; 3361 3362 if (*I) 3363 OS << " B" << (*I)->getBlockID(); 3364 else 3365 OS << " NULL"; 3366 } 3367 3368 OS << '\n'; 3369 } 3370} 3371 3372 3373/// dump - A simple pretty printer of a CFG that outputs to stderr. 3374void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 3375 3376/// print - A simple pretty printer of a CFG that outputs to an ostream. 3377void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 3378 StmtPrinterHelper Helper(this, LO); 3379 3380 // Print the entry block. 3381 print_block(OS, this, getEntry(), &Helper, true); 3382 3383 // Iterate through the CFGBlocks and print them one by one. 3384 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 3385 // Skip the entry block, because we already printed it. 3386 if (&(**I) == &getEntry() || &(**I) == &getExit()) 3387 continue; 3388 3389 print_block(OS, this, **I, &Helper, true); 3390 } 3391 3392 // Print the exit block. 3393 print_block(OS, this, getExit(), &Helper, true); 3394 OS.flush(); 3395} 3396 3397/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 3398void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 3399 print(llvm::errs(), cfg, LO); 3400} 3401 3402/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 3403/// Generally this will only be called from CFG::print. 3404void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 3405 const LangOptions &LO) const { 3406 StmtPrinterHelper Helper(cfg, LO); 3407 print_block(OS, cfg, *this, &Helper, true); 3408} 3409 3410/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 3411void CFGBlock::printTerminator(llvm::raw_ostream &OS, 3412 const LangOptions &LO) const { 3413 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 3414 TPrinter.Visit(const_cast<Stmt*>(getTerminator().getStmt())); 3415} 3416 3417Stmt* CFGBlock::getTerminatorCondition() { 3418 Stmt *Terminator = this->Terminator; 3419 if (!Terminator) 3420 return NULL; 3421 3422 Expr* E = NULL; 3423 3424 switch (Terminator->getStmtClass()) { 3425 default: 3426 break; 3427 3428 case Stmt::ForStmtClass: 3429 E = cast<ForStmt>(Terminator)->getCond(); 3430 break; 3431 3432 case Stmt::WhileStmtClass: 3433 E = cast<WhileStmt>(Terminator)->getCond(); 3434 break; 3435 3436 case Stmt::DoStmtClass: 3437 E = cast<DoStmt>(Terminator)->getCond(); 3438 break; 3439 3440 case Stmt::IfStmtClass: 3441 E = cast<IfStmt>(Terminator)->getCond(); 3442 break; 3443 3444 case Stmt::ChooseExprClass: 3445 E = cast<ChooseExpr>(Terminator)->getCond(); 3446 break; 3447 3448 case Stmt::IndirectGotoStmtClass: 3449 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 3450 break; 3451 3452 case Stmt::SwitchStmtClass: 3453 E = cast<SwitchStmt>(Terminator)->getCond(); 3454 break; 3455 3456 case Stmt::BinaryConditionalOperatorClass: 3457 E = cast<BinaryConditionalOperator>(Terminator)->getCond(); 3458 break; 3459 3460 case Stmt::ConditionalOperatorClass: 3461 E = cast<ConditionalOperator>(Terminator)->getCond(); 3462 break; 3463 3464 case Stmt::BinaryOperatorClass: // '&&' and '||' 3465 E = cast<BinaryOperator>(Terminator)->getLHS(); 3466 break; 3467 3468 case Stmt::ObjCForCollectionStmtClass: 3469 return Terminator; 3470 } 3471 3472 return E ? E->IgnoreParens() : NULL; 3473} 3474 3475bool CFGBlock::hasBinaryBranchTerminator() const { 3476 const Stmt *Terminator = this->Terminator; 3477 if (!Terminator) 3478 return false; 3479 3480 Expr* E = NULL; 3481 3482 switch (Terminator->getStmtClass()) { 3483 default: 3484 return false; 3485 3486 case Stmt::ForStmtClass: 3487 case Stmt::WhileStmtClass: 3488 case Stmt::DoStmtClass: 3489 case Stmt::IfStmtClass: 3490 case Stmt::ChooseExprClass: 3491 case Stmt::BinaryConditionalOperatorClass: 3492 case Stmt::ConditionalOperatorClass: 3493 case Stmt::BinaryOperatorClass: 3494 return true; 3495 } 3496 3497 return E ? E->IgnoreParens() : NULL; 3498} 3499 3500 3501//===----------------------------------------------------------------------===// 3502// CFG Graphviz Visualization 3503//===----------------------------------------------------------------------===// 3504 3505 3506#ifndef NDEBUG 3507static StmtPrinterHelper* GraphHelper; 3508#endif 3509 3510void CFG::viewCFG(const LangOptions &LO) const { 3511#ifndef NDEBUG 3512 StmtPrinterHelper H(this, LO); 3513 GraphHelper = &H; 3514 llvm::ViewGraph(this,"CFG"); 3515 GraphHelper = NULL; 3516#endif 3517} 3518 3519namespace llvm { 3520template<> 3521struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 3522 3523 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 3524 3525 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 3526 3527#ifndef NDEBUG 3528 std::string OutSStr; 3529 llvm::raw_string_ostream Out(OutSStr); 3530 print_block(Out,Graph, *Node, GraphHelper, false); 3531 std::string& OutStr = Out.str(); 3532 3533 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 3534 3535 // Process string output to make it nicer... 3536 for (unsigned i = 0; i != OutStr.length(); ++i) 3537 if (OutStr[i] == '\n') { // Left justify 3538 OutStr[i] = '\\'; 3539 OutStr.insert(OutStr.begin()+i+1, 'l'); 3540 } 3541 3542 return OutStr; 3543#else 3544 return ""; 3545#endif 3546 } 3547}; 3548} // end namespace llvm 3549