CFG.cpp revision 4347259d31856682ac492d955359add71613f1c3
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39class AddStmtChoice { 40public: 41 enum Kind { NotAlwaysAdd = 0, AlwaysAdd, AlwaysAddAsLValue }; 42public: 43 AddStmtChoice(Kind kind) : k(kind) {} 44 bool alwaysAdd() const { return k != NotAlwaysAdd; } 45 bool asLValue() const { return k == AlwaysAddAsLValue; } 46private: 47 Kind k; 48}; 49 50/// CFGBuilder - This class implements CFG construction from an AST. 51/// The builder is stateful: an instance of the builder should be used to only 52/// construct a single CFG. 53/// 54/// Example usage: 55/// 56/// CFGBuilder builder; 57/// CFG* cfg = builder.BuildAST(stmt1); 58/// 59/// CFG construction is done via a recursive walk of an AST. We actually parse 60/// the AST in reverse order so that the successor of a basic block is 61/// constructed prior to its predecessor. This allows us to nicely capture 62/// implicit fall-throughs without extra basic blocks. 63/// 64class CFGBuilder { 65 ASTContext *Context; 66 llvm::OwningPtr<CFG> cfg; 67 68 CFGBlock* Block; 69 CFGBlock* Succ; 70 CFGBlock* ContinueTargetBlock; 71 CFGBlock* BreakTargetBlock; 72 CFGBlock* SwitchTerminatedBlock; 73 CFGBlock* DefaultCaseBlock; 74 CFGBlock* TryTerminatedBlock; 75 76 // LabelMap records the mapping from Label expressions to their blocks. 77 typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy; 78 LabelMapTy LabelMap; 79 80 // A list of blocks that end with a "goto" that must be backpatched to their 81 // resolved targets upon completion of CFG construction. 82 typedef std::vector<CFGBlock*> BackpatchBlocksTy; 83 BackpatchBlocksTy BackpatchBlocks; 84 85 // A list of labels whose address has been taken (for indirect gotos). 86 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 87 LabelSetTy AddressTakenLabels; 88 89public: 90 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 91 Block(NULL), Succ(NULL), 92 ContinueTargetBlock(NULL), BreakTargetBlock(NULL), 93 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 94 TryTerminatedBlock(NULL) {} 95 96 // buildCFG - Used by external clients to construct the CFG. 97 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, bool AddScopes); 98 99private: 100 // Visitors to walk an AST and construct the CFG. 101 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 102 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 103 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 104 CFGBlock *VisitBreakStmt(BreakStmt *B); 105 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 106 CFGBlock *VisitCaseStmt(CaseStmt *C); 107 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 108 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 109 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, 110 AddStmtChoice asc); 111 CFGBlock *VisitContinueStmt(ContinueStmt *C); 112 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 113 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 114 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 115 CFGBlock *VisitDeclStmt(DeclStmt *DS); 116 CFGBlock *VisitDeclSubExpr(Decl* D); 117 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 118 CFGBlock *VisitDoStmt(DoStmt *D); 119 CFGBlock *VisitForStmt(ForStmt *F); 120 CFGBlock *VisitGotoStmt(GotoStmt* G); 121 CFGBlock *VisitIfStmt(IfStmt *I); 122 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 123 CFGBlock *VisitLabelStmt(LabelStmt *L); 124 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 125 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 126 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 127 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 128 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 129 CFGBlock *VisitReturnStmt(ReturnStmt* R); 130 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 131 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 132 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 133 CFGBlock *VisitWhileStmt(WhileStmt *W); 134 135 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 136 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 137 CFGBlock *VisitChildren(Stmt* S); 138 139 // NYS == Not Yet Supported 140 CFGBlock* NYS() { 141 badCFG = true; 142 return Block; 143 } 144 145 CFGBlock *StartScope(Stmt *S, CFGBlock *B) { 146 if (!AddScopes) 147 return B; 148 149 if (B == 0) 150 B = createBlock(); 151 B->StartScope(S, cfg->getBumpVectorContext()); 152 return B; 153 } 154 155 void EndScope(Stmt *S) { 156 if (!AddScopes) 157 return; 158 159 if (Block == 0) 160 Block = createBlock(); 161 Block->EndScope(S, cfg->getBumpVectorContext()); 162 } 163 164 void autoCreateBlock() { if (!Block) Block = createBlock(); } 165 CFGBlock *createBlock(bool add_successor = true); 166 bool FinishBlock(CFGBlock* B); 167 CFGBlock *addStmt(Stmt *S, AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 168 return Visit(S, asc); 169 } 170 171 void AppendStmt(CFGBlock *B, Stmt *S, 172 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 173 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 174 } 175 176 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 177 B->addSuccessor(S, cfg->getBumpVectorContext()); 178 } 179 180 /// TryResult - a class representing a variant over the values 181 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 182 /// and is used by the CFGBuilder to decide if a branch condition 183 /// can be decided up front during CFG construction. 184 class TryResult { 185 int X; 186 public: 187 TryResult(bool b) : X(b ? 1 : 0) {} 188 TryResult() : X(-1) {} 189 190 bool isTrue() const { return X == 1; } 191 bool isFalse() const { return X == 0; } 192 bool isKnown() const { return X >= 0; } 193 void negate() { 194 assert(isKnown()); 195 X ^= 0x1; 196 } 197 }; 198 199 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 200 /// if we can evaluate to a known value, otherwise return -1. 201 TryResult TryEvaluateBool(Expr *S) { 202 Expr::EvalResult Result; 203 if (!S->isTypeDependent() && !S->isValueDependent() && 204 S->Evaluate(Result, *Context) && Result.Val.isInt()) 205 return Result.Val.getInt().getBoolValue(); 206 207 return TryResult(); 208 } 209 210 bool badCFG; 211 bool AddScopes; 212}; 213 214// FIXME: Add support for dependent-sized array types in C++? 215// Does it even make sense to build a CFG for an uninstantiated template? 216static VariableArrayType* FindVA(Type* t) { 217 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 218 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 219 if (vat->getSizeExpr()) 220 return vat; 221 222 t = vt->getElementType().getTypePtr(); 223 } 224 225 return 0; 226} 227 228/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 229/// arbitrary statement. Examples include a single expression or a function 230/// body (compound statement). The ownership of the returned CFG is 231/// transferred to the caller. If CFG construction fails, this method returns 232/// NULL. 233CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 234 bool AddScopes) { 235 Context = C; 236 assert(cfg.get()); 237 if (!Statement) 238 return NULL; 239 240 this->AddScopes = AddScopes; 241 badCFG = false; 242 243 // Create an empty block that will serve as the exit block for the CFG. Since 244 // this is the first block added to the CFG, it will be implicitly registered 245 // as the exit block. 246 Succ = createBlock(); 247 assert(Succ == &cfg->getExit()); 248 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 249 250 // Visit the statements and create the CFG. 251 CFGBlock* B = addStmt(Statement); 252 253 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 254 // FIXME: Add code for base initializers and member initializers. 255 (void)CD; 256 } 257 if (!B) 258 B = Succ; 259 260 if (B) { 261 // Finalize the last constructed block. This usually involves reversing the 262 // order of the statements in the block. 263 if (Block) FinishBlock(B); 264 265 // Backpatch the gotos whose label -> block mappings we didn't know when we 266 // encountered them. 267 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 268 E = BackpatchBlocks.end(); I != E; ++I ) { 269 270 CFGBlock* B = *I; 271 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 272 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 273 274 // If there is no target for the goto, then we are looking at an 275 // incomplete AST. Handle this by not registering a successor. 276 if (LI == LabelMap.end()) continue; 277 278 AddSuccessor(B, LI->second); 279 } 280 281 // Add successors to the Indirect Goto Dispatch block (if we have one). 282 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 283 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 284 E = AddressTakenLabels.end(); I != E; ++I ) { 285 286 // Lookup the target block. 287 LabelMapTy::iterator LI = LabelMap.find(*I); 288 289 // If there is no target block that contains label, then we are looking 290 // at an incomplete AST. Handle this by not registering a successor. 291 if (LI == LabelMap.end()) continue; 292 293 AddSuccessor(B, LI->second); 294 } 295 296 Succ = B; 297 } 298 299 // Create an empty entry block that has no predecessors. 300 cfg->setEntry(createBlock()); 301 302 return badCFG ? NULL : cfg.take(); 303} 304 305/// createBlock - Used to lazily create blocks that are connected 306/// to the current (global) succcessor. 307CFGBlock* CFGBuilder::createBlock(bool add_successor) { 308 CFGBlock* B = cfg->createBlock(); 309 if (add_successor && Succ) 310 AddSuccessor(B, Succ); 311 return B; 312} 313 314/// FinishBlock - "Finalize" the block by checking if we have a bad CFG. 315bool CFGBuilder::FinishBlock(CFGBlock* B) { 316 if (badCFG) 317 return false; 318 319 assert(B); 320 return true; 321} 322 323/// Visit - Walk the subtree of a statement and add extra 324/// blocks for ternary operators, &&, and ||. We also process "," and 325/// DeclStmts (which may contain nested control-flow). 326CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 327tryAgain: 328 switch (S->getStmtClass()) { 329 default: 330 return VisitStmt(S, asc); 331 332 case Stmt::AddrLabelExprClass: 333 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 334 335 case Stmt::BinaryOperatorClass: 336 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 337 338 case Stmt::BlockExprClass: 339 return VisitBlockExpr(cast<BlockExpr>(S), asc); 340 341 case Stmt::BreakStmtClass: 342 return VisitBreakStmt(cast<BreakStmt>(S)); 343 344 case Stmt::CallExprClass: 345 return VisitCallExpr(cast<CallExpr>(S), asc); 346 347 case Stmt::CaseStmtClass: 348 return VisitCaseStmt(cast<CaseStmt>(S)); 349 350 case Stmt::ChooseExprClass: 351 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 352 353 case Stmt::CompoundStmtClass: 354 return VisitCompoundStmt(cast<CompoundStmt>(S)); 355 356 case Stmt::ConditionalOperatorClass: 357 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 358 359 case Stmt::ContinueStmtClass: 360 return VisitContinueStmt(cast<ContinueStmt>(S)); 361 362 case Stmt::CXXCatchStmtClass: 363 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 364 365 case Stmt::CXXThrowExprClass: 366 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 367 368 case Stmt::CXXTryStmtClass: 369 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 370 371 case Stmt::DeclStmtClass: 372 return VisitDeclStmt(cast<DeclStmt>(S)); 373 374 case Stmt::DefaultStmtClass: 375 return VisitDefaultStmt(cast<DefaultStmt>(S)); 376 377 case Stmt::DoStmtClass: 378 return VisitDoStmt(cast<DoStmt>(S)); 379 380 case Stmt::ForStmtClass: 381 return VisitForStmt(cast<ForStmt>(S)); 382 383 case Stmt::GotoStmtClass: 384 return VisitGotoStmt(cast<GotoStmt>(S)); 385 386 case Stmt::IfStmtClass: 387 return VisitIfStmt(cast<IfStmt>(S)); 388 389 case Stmt::IndirectGotoStmtClass: 390 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 391 392 case Stmt::LabelStmtClass: 393 return VisitLabelStmt(cast<LabelStmt>(S)); 394 395 case Stmt::ObjCAtCatchStmtClass: 396 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 397 398 case Stmt::ObjCAtSynchronizedStmtClass: 399 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 400 401 case Stmt::ObjCAtThrowStmtClass: 402 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 403 404 case Stmt::ObjCAtTryStmtClass: 405 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 406 407 case Stmt::ObjCForCollectionStmtClass: 408 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 409 410 case Stmt::ParenExprClass: 411 S = cast<ParenExpr>(S)->getSubExpr(); 412 goto tryAgain; 413 414 case Stmt::NullStmtClass: 415 return Block; 416 417 case Stmt::ReturnStmtClass: 418 return VisitReturnStmt(cast<ReturnStmt>(S)); 419 420 case Stmt::SizeOfAlignOfExprClass: 421 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 422 423 case Stmt::StmtExprClass: 424 return VisitStmtExpr(cast<StmtExpr>(S), asc); 425 426 case Stmt::SwitchStmtClass: 427 return VisitSwitchStmt(cast<SwitchStmt>(S)); 428 429 case Stmt::WhileStmtClass: 430 return VisitWhileStmt(cast<WhileStmt>(S)); 431 } 432} 433 434CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 435 if (asc.alwaysAdd()) { 436 autoCreateBlock(); 437 AppendStmt(Block, S, asc); 438 } 439 440 return VisitChildren(S); 441} 442 443/// VisitChildren - Visit the children of a Stmt. 444CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 445 CFGBlock *B = Block; 446 for (Stmt::child_iterator I = Terminator->child_begin(), 447 E = Terminator->child_end(); I != E; ++I) { 448 if (*I) B = Visit(*I); 449 } 450 return B; 451} 452 453CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 454 AddStmtChoice asc) { 455 AddressTakenLabels.insert(A->getLabel()); 456 457 if (asc.alwaysAdd()) { 458 autoCreateBlock(); 459 AppendStmt(Block, A, asc); 460 } 461 462 return Block; 463} 464 465CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 466 AddStmtChoice asc) { 467 if (B->isLogicalOp()) { // && or || 468 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 469 AppendStmt(ConfluenceBlock, B, asc); 470 471 if (!FinishBlock(ConfluenceBlock)) 472 return 0; 473 474 // create the block evaluating the LHS 475 CFGBlock* LHSBlock = createBlock(false); 476 LHSBlock->setTerminator(B); 477 478 // create the block evaluating the RHS 479 Succ = ConfluenceBlock; 480 Block = NULL; 481 CFGBlock* RHSBlock = addStmt(B->getRHS()); 482 if (!FinishBlock(RHSBlock)) 483 return 0; 484 485 // See if this is a known constant. 486 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 487 if (KnownVal.isKnown() && (B->getOpcode() == BinaryOperator::LOr)) 488 KnownVal.negate(); 489 490 // Now link the LHSBlock with RHSBlock. 491 if (B->getOpcode() == BinaryOperator::LOr) { 492 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 493 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 494 } else { 495 assert(B->getOpcode() == BinaryOperator::LAnd); 496 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 497 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 498 } 499 500 // Generate the blocks for evaluating the LHS. 501 Block = LHSBlock; 502 return addStmt(B->getLHS()); 503 } 504 else if (B->getOpcode() == BinaryOperator::Comma) { // , 505 autoCreateBlock(); 506 AppendStmt(Block, B, asc); 507 addStmt(B->getRHS()); 508 return addStmt(B->getLHS()); 509 } 510 511 return VisitStmt(B, asc); 512} 513 514CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 515 if (asc.alwaysAdd()) { 516 autoCreateBlock(); 517 AppendStmt(Block, E, asc); 518 } 519 return Block; 520} 521 522CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 523 // "break" is a control-flow statement. Thus we stop processing the current 524 // block. 525 if (Block && !FinishBlock(Block)) 526 return 0; 527 528 // Now create a new block that ends with the break statement. 529 Block = createBlock(false); 530 Block->setTerminator(B); 531 532 // If there is no target for the break, then we are looking at an incomplete 533 // AST. This means that the CFG cannot be constructed. 534 if (BreakTargetBlock) 535 AddSuccessor(Block, BreakTargetBlock); 536 else 537 badCFG = true; 538 539 540 return Block; 541} 542 543CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 544 // If this is a call to a no-return function, this stops the block here. 545 bool NoReturn = false; 546 if (C->getCallee()->getType().getNoReturnAttr()) { 547 NoReturn = true; 548 } 549 550 bool CanThrow = false; 551 552 // Languages without exceptions are assumed to not throw. 553 if (Context->getLangOptions().Exceptions) { 554 CanThrow = true; 555 } 556 557 if (FunctionDecl *FD = C->getDirectCallee()) { 558 if (FD->hasAttr<NoReturnAttr>()) 559 NoReturn = true; 560 if (FD->hasAttr<NoThrowAttr>()) 561 CanThrow = false; 562 } 563 564 if (!NoReturn && !CanThrow) 565 return VisitStmt(C, asc); 566 567 if (Block) { 568 Succ = Block; 569 if (!FinishBlock(Block)) 570 return 0; 571 } 572 573 Block = createBlock(!NoReturn); 574 AppendStmt(Block, C, asc); 575 576 if (NoReturn) { 577 // Wire this to the exit block directly. 578 AddSuccessor(Block, &cfg->getExit()); 579 } 580 if (CanThrow) { 581 // Add exceptional edges. 582 if (TryTerminatedBlock) 583 AddSuccessor(Block, TryTerminatedBlock); 584 else 585 AddSuccessor(Block, &cfg->getExit()); 586 } 587 588 return VisitChildren(C); 589} 590 591CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 592 AddStmtChoice asc) { 593 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 594 AppendStmt(ConfluenceBlock, C, asc); 595 if (!FinishBlock(ConfluenceBlock)) 596 return 0; 597 598 Succ = ConfluenceBlock; 599 Block = NULL; 600 CFGBlock* LHSBlock = addStmt(C->getLHS()); 601 if (!FinishBlock(LHSBlock)) 602 return 0; 603 604 Succ = ConfluenceBlock; 605 Block = NULL; 606 CFGBlock* RHSBlock = addStmt(C->getRHS()); 607 if (!FinishBlock(RHSBlock)) 608 return 0; 609 610 Block = createBlock(false); 611 // See if this is a known constant. 612 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 613 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 614 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 615 Block->setTerminator(C); 616 return addStmt(C->getCond()); 617} 618 619 620CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 621 EndScope(C); 622 623 CFGBlock* LastBlock = Block; 624 625 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 626 I != E; ++I ) { 627 LastBlock = addStmt(*I); 628 629 if (badCFG) 630 return NULL; 631 } 632 633 LastBlock = StartScope(C, LastBlock); 634 635 return LastBlock; 636} 637 638CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 639 AddStmtChoice asc) { 640 // Create the confluence block that will "merge" the results of the ternary 641 // expression. 642 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 643 AppendStmt(ConfluenceBlock, C, asc); 644 if (!FinishBlock(ConfluenceBlock)) 645 return 0; 646 647 // Create a block for the LHS expression if there is an LHS expression. A 648 // GCC extension allows LHS to be NULL, causing the condition to be the 649 // value that is returned instead. 650 // e.g: x ?: y is shorthand for: x ? x : y; 651 Succ = ConfluenceBlock; 652 Block = NULL; 653 CFGBlock* LHSBlock = NULL; 654 if (C->getLHS()) { 655 LHSBlock = addStmt(C->getLHS()); 656 if (!FinishBlock(LHSBlock)) 657 return 0; 658 Block = NULL; 659 } 660 661 // Create the block for the RHS expression. 662 Succ = ConfluenceBlock; 663 CFGBlock* RHSBlock = addStmt(C->getRHS()); 664 if (!FinishBlock(RHSBlock)) 665 return 0; 666 667 // Create the block that will contain the condition. 668 Block = createBlock(false); 669 670 // See if this is a known constant. 671 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 672 if (LHSBlock) { 673 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 674 } else { 675 if (KnownVal.isFalse()) { 676 // If we know the condition is false, add NULL as the successor for 677 // the block containing the condition. In this case, the confluence 678 // block will have just one predecessor. 679 AddSuccessor(Block, 0); 680 assert(ConfluenceBlock->pred_size() == 1); 681 } else { 682 // If we have no LHS expression, add the ConfluenceBlock as a direct 683 // successor for the block containing the condition. Moreover, we need to 684 // reverse the order of the predecessors in the ConfluenceBlock because 685 // the RHSBlock will have been added to the succcessors already, and we 686 // want the first predecessor to the the block containing the expression 687 // for the case when the ternary expression evaluates to true. 688 AddSuccessor(Block, ConfluenceBlock); 689 assert(ConfluenceBlock->pred_size() == 2); 690 std::reverse(ConfluenceBlock->pred_begin(), 691 ConfluenceBlock->pred_end()); 692 } 693 } 694 695 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 696 Block->setTerminator(C); 697 return addStmt(C->getCond()); 698} 699 700CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 701 autoCreateBlock(); 702 703 if (DS->isSingleDecl()) { 704 AppendStmt(Block, DS); 705 return VisitDeclSubExpr(DS->getSingleDecl()); 706 } 707 708 CFGBlock *B = 0; 709 710 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 711 typedef llvm::SmallVector<Decl*,10> BufTy; 712 BufTy Buf(DS->decl_begin(), DS->decl_end()); 713 714 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 715 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 716 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 717 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 718 719 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 720 // automatically freed with the CFG. 721 DeclGroupRef DG(*I); 722 Decl *D = *I; 723 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 724 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 725 726 // Append the fake DeclStmt to block. 727 AppendStmt(Block, DSNew); 728 B = VisitDeclSubExpr(D); 729 } 730 731 return B; 732} 733 734/// VisitDeclSubExpr - Utility method to add block-level expressions for 735/// initializers in Decls. 736CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 737 assert(Block); 738 739 VarDecl *VD = dyn_cast<VarDecl>(D); 740 741 if (!VD) 742 return Block; 743 744 Expr *Init = VD->getInit(); 745 746 if (Init) { 747 // Optimization: Don't create separate block-level statements for literals. 748 switch (Init->getStmtClass()) { 749 case Stmt::IntegerLiteralClass: 750 case Stmt::CharacterLiteralClass: 751 case Stmt::StringLiteralClass: 752 break; 753 default: 754 Block = addStmt(Init, 755 VD->getType()->isReferenceType() 756 ? AddStmtChoice::AlwaysAddAsLValue 757 : AddStmtChoice::AlwaysAdd); 758 } 759 } 760 761 // If the type of VD is a VLA, then we must process its size expressions. 762 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 763 VA = FindVA(VA->getElementType().getTypePtr())) 764 Block = addStmt(VA->getSizeExpr()); 765 766 return Block; 767} 768 769CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 770 // We may see an if statement in the middle of a basic block, or it may be the 771 // first statement we are processing. In either case, we create a new basic 772 // block. First, we create the blocks for the then...else statements, and 773 // then we create the block containing the if statement. If we were in the 774 // middle of a block, we stop processing that block. That block is then the 775 // implicit successor for the "then" and "else" clauses. 776 777 // The block we were proccessing is now finished. Make it the successor 778 // block. 779 if (Block) { 780 Succ = Block; 781 if (!FinishBlock(Block)) 782 return 0; 783 } 784 785 // Process the false branch. 786 CFGBlock* ElseBlock = Succ; 787 788 if (Stmt* Else = I->getElse()) { 789 SaveAndRestore<CFGBlock*> sv(Succ); 790 791 // NULL out Block so that the recursive call to Visit will 792 // create a new basic block. 793 Block = NULL; 794 ElseBlock = addStmt(Else); 795 796 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 797 ElseBlock = sv.get(); 798 else if (Block) { 799 if (!FinishBlock(ElseBlock)) 800 return 0; 801 } 802 } 803 804 // Process the true branch. 805 CFGBlock* ThenBlock; 806 { 807 Stmt* Then = I->getThen(); 808 assert(Then); 809 SaveAndRestore<CFGBlock*> sv(Succ); 810 Block = NULL; 811 ThenBlock = addStmt(Then); 812 813 if (!ThenBlock) { 814 // We can reach here if the "then" body has all NullStmts. 815 // Create an empty block so we can distinguish between true and false 816 // branches in path-sensitive analyses. 817 ThenBlock = createBlock(false); 818 AddSuccessor(ThenBlock, sv.get()); 819 } else if (Block) { 820 if (!FinishBlock(ThenBlock)) 821 return 0; 822 } 823 } 824 825 // Now create a new block containing the if statement. 826 Block = createBlock(false); 827 828 // Set the terminator of the new block to the If statement. 829 Block->setTerminator(I); 830 831 // See if this is a known constant. 832 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 833 834 // Now add the successors. 835 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 836 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 837 838 // Add the condition as the last statement in the new block. This may create 839 // new blocks as the condition may contain control-flow. Any newly created 840 // blocks will be pointed to be "Block". 841 Block = addStmt(I->getCond()); 842 843 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 844 // and the condition variable initialization to the CFG. 845 if (VarDecl *VD = I->getConditionVariable()) { 846 if (Expr *Init = VD->getInit()) { 847 autoCreateBlock(); 848 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 849 addStmt(Init); 850 } 851 } 852 853 return Block; 854} 855 856 857CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 858 // If we were in the middle of a block we stop processing that block. 859 // 860 // NOTE: If a "return" appears in the middle of a block, this means that the 861 // code afterwards is DEAD (unreachable). We still keep a basic block 862 // for that code; a simple "mark-and-sweep" from the entry block will be 863 // able to report such dead blocks. 864 if (Block) 865 FinishBlock(Block); 866 867 // Create the new block. 868 Block = createBlock(false); 869 870 // The Exit block is the only successor. 871 AddSuccessor(Block, &cfg->getExit()); 872 873 // Add the return statement to the block. This may create new blocks if R 874 // contains control-flow (short-circuit operations). 875 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 876} 877 878CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 879 // Get the block of the labeled statement. Add it to our map. 880 addStmt(L->getSubStmt()); 881 CFGBlock* LabelBlock = Block; 882 883 if (!LabelBlock) // This can happen when the body is empty, i.e. 884 LabelBlock = createBlock(); // scopes that only contains NullStmts. 885 886 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 887 LabelMap[ L ] = LabelBlock; 888 889 // Labels partition blocks, so this is the end of the basic block we were 890 // processing (L is the block's label). Because this is label (and we have 891 // already processed the substatement) there is no extra control-flow to worry 892 // about. 893 LabelBlock->setLabel(L); 894 if (!FinishBlock(LabelBlock)) 895 return 0; 896 897 // We set Block to NULL to allow lazy creation of a new block (if necessary); 898 Block = NULL; 899 900 // This block is now the implicit successor of other blocks. 901 Succ = LabelBlock; 902 903 return LabelBlock; 904} 905 906CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 907 // Goto is a control-flow statement. Thus we stop processing the current 908 // block and create a new one. 909 if (Block) 910 FinishBlock(Block); 911 912 Block = createBlock(false); 913 Block->setTerminator(G); 914 915 // If we already know the mapping to the label block add the successor now. 916 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 917 918 if (I == LabelMap.end()) 919 // We will need to backpatch this block later. 920 BackpatchBlocks.push_back(Block); 921 else 922 AddSuccessor(Block, I->second); 923 924 return Block; 925} 926 927CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 928 CFGBlock* LoopSuccessor = NULL; 929 930 // "for" is a control-flow statement. Thus we stop processing the current 931 // block. 932 if (Block) { 933 if (!FinishBlock(Block)) 934 return 0; 935 LoopSuccessor = Block; 936 } else 937 LoopSuccessor = Succ; 938 939 // Because of short-circuit evaluation, the condition of the loop can span 940 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 941 // evaluate the condition. 942 CFGBlock* ExitConditionBlock = createBlock(false); 943 CFGBlock* EntryConditionBlock = ExitConditionBlock; 944 945 // Set the terminator for the "exit" condition block. 946 ExitConditionBlock->setTerminator(F); 947 948 // Now add the actual condition to the condition block. Because the condition 949 // itself may contain control-flow, new blocks may be created. 950 if (Stmt* C = F->getCond()) { 951 Block = ExitConditionBlock; 952 EntryConditionBlock = addStmt(C); 953 assert(Block == EntryConditionBlock); 954 955 // If this block contains a condition variable, add both the condition 956 // variable and initializer to the CFG. 957 if (VarDecl *VD = F->getConditionVariable()) { 958 if (Expr *Init = VD->getInit()) { 959 autoCreateBlock(); 960 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 961 EntryConditionBlock = addStmt(Init); 962 assert(Block == EntryConditionBlock); 963 } 964 } 965 966 if (Block) { 967 if (!FinishBlock(EntryConditionBlock)) 968 return 0; 969 } 970 } 971 972 // The condition block is the implicit successor for the loop body as well as 973 // any code above the loop. 974 Succ = EntryConditionBlock; 975 976 // See if this is a known constant. 977 TryResult KnownVal(true); 978 979 if (F->getCond()) 980 KnownVal = TryEvaluateBool(F->getCond()); 981 982 // Now create the loop body. 983 { 984 assert(F->getBody()); 985 986 // Save the current values for Block, Succ, and continue and break targets 987 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 988 save_continue(ContinueTargetBlock), 989 save_break(BreakTargetBlock); 990 991 // Create a new block to contain the (bottom) of the loop body. 992 Block = NULL; 993 994 if (Stmt* I = F->getInc()) { 995 // Generate increment code in its own basic block. This is the target of 996 // continue statements. 997 Succ = addStmt(I); 998 } else { 999 // No increment code. Create a special, empty, block that is used as the 1000 // target block for "looping back" to the start of the loop. 1001 assert(Succ == EntryConditionBlock); 1002 Succ = createBlock(); 1003 } 1004 1005 // Finish up the increment (or empty) block if it hasn't been already. 1006 if (Block) { 1007 assert(Block == Succ); 1008 if (!FinishBlock(Block)) 1009 return 0; 1010 Block = 0; 1011 } 1012 1013 ContinueTargetBlock = Succ; 1014 1015 // The starting block for the loop increment is the block that should 1016 // represent the 'loop target' for looping back to the start of the loop. 1017 ContinueTargetBlock->setLoopTarget(F); 1018 1019 // All breaks should go to the code following the loop. 1020 BreakTargetBlock = LoopSuccessor; 1021 1022 // Now populate the body block, and in the process create new blocks as we 1023 // walk the body of the loop. 1024 CFGBlock* BodyBlock = addStmt(F->getBody()); 1025 1026 if (!BodyBlock) 1027 BodyBlock = ContinueTargetBlock; // can happen for "for (...;...;...) ;" 1028 else if (Block && !FinishBlock(BodyBlock)) 1029 return 0; 1030 1031 // This new body block is a successor to our "exit" condition block. 1032 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1033 } 1034 1035 // Link up the condition block with the code that follows the loop. (the 1036 // false branch). 1037 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1038 1039 // If the loop contains initialization, create a new block for those 1040 // statements. This block can also contain statements that precede the loop. 1041 if (Stmt* I = F->getInit()) { 1042 Block = createBlock(); 1043 return addStmt(I); 1044 } else { 1045 // There is no loop initialization. We are thus basically a while loop. 1046 // NULL out Block to force lazy block construction. 1047 Block = NULL; 1048 Succ = EntryConditionBlock; 1049 return EntryConditionBlock; 1050 } 1051} 1052 1053CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1054 // Objective-C fast enumeration 'for' statements: 1055 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1056 // 1057 // for ( Type newVariable in collection_expression ) { statements } 1058 // 1059 // becomes: 1060 // 1061 // prologue: 1062 // 1. collection_expression 1063 // T. jump to loop_entry 1064 // loop_entry: 1065 // 1. side-effects of element expression 1066 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1067 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1068 // TB: 1069 // statements 1070 // T. jump to loop_entry 1071 // FB: 1072 // what comes after 1073 // 1074 // and 1075 // 1076 // Type existingItem; 1077 // for ( existingItem in expression ) { statements } 1078 // 1079 // becomes: 1080 // 1081 // the same with newVariable replaced with existingItem; the binding works 1082 // the same except that for one ObjCForCollectionStmt::getElement() returns 1083 // a DeclStmt and the other returns a DeclRefExpr. 1084 // 1085 1086 CFGBlock* LoopSuccessor = 0; 1087 1088 if (Block) { 1089 if (!FinishBlock(Block)) 1090 return 0; 1091 LoopSuccessor = Block; 1092 Block = 0; 1093 } else 1094 LoopSuccessor = Succ; 1095 1096 // Build the condition blocks. 1097 CFGBlock* ExitConditionBlock = createBlock(false); 1098 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1099 1100 // Set the terminator for the "exit" condition block. 1101 ExitConditionBlock->setTerminator(S); 1102 1103 // The last statement in the block should be the ObjCForCollectionStmt, which 1104 // performs the actual binding to 'element' and determines if there are any 1105 // more items in the collection. 1106 AppendStmt(ExitConditionBlock, S); 1107 Block = ExitConditionBlock; 1108 1109 // Walk the 'element' expression to see if there are any side-effects. We 1110 // generate new blocks as necesary. We DON'T add the statement by default to 1111 // the CFG unless it contains control-flow. 1112 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1113 if (Block) { 1114 if (!FinishBlock(EntryConditionBlock)) 1115 return 0; 1116 Block = 0; 1117 } 1118 1119 // The condition block is the implicit successor for the loop body as well as 1120 // any code above the loop. 1121 Succ = EntryConditionBlock; 1122 1123 // Now create the true branch. 1124 { 1125 // Save the current values for Succ, continue and break targets. 1126 SaveAndRestore<CFGBlock*> save_Succ(Succ), 1127 save_continue(ContinueTargetBlock), save_break(BreakTargetBlock); 1128 1129 BreakTargetBlock = LoopSuccessor; 1130 ContinueTargetBlock = EntryConditionBlock; 1131 1132 CFGBlock* BodyBlock = addStmt(S->getBody()); 1133 1134 if (!BodyBlock) 1135 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1136 else if (Block) { 1137 if (!FinishBlock(BodyBlock)) 1138 return 0; 1139 } 1140 1141 // This new body block is a successor to our "exit" condition block. 1142 AddSuccessor(ExitConditionBlock, BodyBlock); 1143 } 1144 1145 // Link up the condition block with the code that follows the loop. 1146 // (the false branch). 1147 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1148 1149 // Now create a prologue block to contain the collection expression. 1150 Block = createBlock(); 1151 return addStmt(S->getCollection()); 1152} 1153 1154CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1155 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1156 1157 // Inline the body. 1158 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1159 1160 // The sync body starts its own basic block. This makes it a little easier 1161 // for diagnostic clients. 1162 if (SyncBlock) { 1163 if (!FinishBlock(SyncBlock)) 1164 return 0; 1165 1166 Block = 0; 1167 } 1168 1169 Succ = SyncBlock; 1170 1171 // Inline the sync expression. 1172 return addStmt(S->getSynchExpr()); 1173} 1174 1175CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1176 // FIXME 1177 return NYS(); 1178} 1179 1180CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1181 CFGBlock* LoopSuccessor = NULL; 1182 1183 // "while" is a control-flow statement. Thus we stop processing the current 1184 // block. 1185 if (Block) { 1186 if (!FinishBlock(Block)) 1187 return 0; 1188 LoopSuccessor = Block; 1189 } else 1190 LoopSuccessor = Succ; 1191 1192 // Because of short-circuit evaluation, the condition of the loop can span 1193 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1194 // evaluate the condition. 1195 CFGBlock* ExitConditionBlock = createBlock(false); 1196 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1197 1198 // Set the terminator for the "exit" condition block. 1199 ExitConditionBlock->setTerminator(W); 1200 1201 // Now add the actual condition to the condition block. Because the condition 1202 // itself may contain control-flow, new blocks may be created. Thus we update 1203 // "Succ" after adding the condition. 1204 if (Stmt* C = W->getCond()) { 1205 Block = ExitConditionBlock; 1206 EntryConditionBlock = addStmt(C); 1207 assert(Block == EntryConditionBlock); 1208 1209 // If this block contains a condition variable, add both the condition 1210 // variable and initializer to the CFG. 1211 if (VarDecl *VD = W->getConditionVariable()) { 1212 if (Expr *Init = VD->getInit()) { 1213 autoCreateBlock(); 1214 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1215 EntryConditionBlock = addStmt(Init); 1216 assert(Block == EntryConditionBlock); 1217 } 1218 } 1219 1220 if (Block) { 1221 if (!FinishBlock(EntryConditionBlock)) 1222 return 0; 1223 } 1224 } 1225 1226 // The condition block is the implicit successor for the loop body as well as 1227 // any code above the loop. 1228 Succ = EntryConditionBlock; 1229 1230 // See if this is a known constant. 1231 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1232 1233 // Process the loop body. 1234 { 1235 assert(W->getBody()); 1236 1237 // Save the current values for Block, Succ, and continue and break targets 1238 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1239 save_continue(ContinueTargetBlock), 1240 save_break(BreakTargetBlock); 1241 1242 // Create an empty block to represent the transition block for looping back 1243 // to the head of the loop. 1244 Block = 0; 1245 assert(Succ == EntryConditionBlock); 1246 Succ = createBlock(); 1247 Succ->setLoopTarget(W); 1248 ContinueTargetBlock = Succ; 1249 1250 // All breaks should go to the code following the loop. 1251 BreakTargetBlock = LoopSuccessor; 1252 1253 // NULL out Block to force lazy instantiation of blocks for the body. 1254 Block = NULL; 1255 1256 // Create the body. The returned block is the entry to the loop body. 1257 CFGBlock* BodyBlock = addStmt(W->getBody()); 1258 1259 if (!BodyBlock) 1260 BodyBlock = ContinueTargetBlock; // can happen for "while(...) ;" 1261 else if (Block) { 1262 if (!FinishBlock(BodyBlock)) 1263 return 0; 1264 } 1265 1266 // Add the loop body entry as a successor to the condition. 1267 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1268 } 1269 1270 // Link up the condition block with the code that follows the loop. (the 1271 // false branch). 1272 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1273 1274 // There can be no more statements in the condition block since we loop back 1275 // to this block. NULL out Block to force lazy creation of another block. 1276 Block = NULL; 1277 1278 // Return the condition block, which is the dominating block for the loop. 1279 Succ = EntryConditionBlock; 1280 return EntryConditionBlock; 1281} 1282 1283 1284CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1285 // FIXME: For now we pretend that @catch and the code it contains does not 1286 // exit. 1287 return Block; 1288} 1289 1290CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1291 // FIXME: This isn't complete. We basically treat @throw like a return 1292 // statement. 1293 1294 // If we were in the middle of a block we stop processing that block. 1295 if (Block && !FinishBlock(Block)) 1296 return 0; 1297 1298 // Create the new block. 1299 Block = createBlock(false); 1300 1301 // The Exit block is the only successor. 1302 AddSuccessor(Block, &cfg->getExit()); 1303 1304 // Add the statement to the block. This may create new blocks if S contains 1305 // control-flow (short-circuit operations). 1306 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1307} 1308 1309CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1310 // If we were in the middle of a block we stop processing that block. 1311 if (Block && !FinishBlock(Block)) 1312 return 0; 1313 1314 // Create the new block. 1315 Block = createBlock(false); 1316 1317 if (TryTerminatedBlock) 1318 // The current try statement is the only successor. 1319 AddSuccessor(Block, TryTerminatedBlock); 1320 else 1321 // otherwise the Exit block is the only successor. 1322 AddSuccessor(Block, &cfg->getExit()); 1323 1324 // Add the statement to the block. This may create new blocks if S contains 1325 // control-flow (short-circuit operations). 1326 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1327} 1328 1329CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1330 CFGBlock* LoopSuccessor = NULL; 1331 1332 // "do...while" is a control-flow statement. Thus we stop processing the 1333 // current block. 1334 if (Block) { 1335 if (!FinishBlock(Block)) 1336 return 0; 1337 LoopSuccessor = Block; 1338 } else 1339 LoopSuccessor = Succ; 1340 1341 // Because of short-circuit evaluation, the condition of the loop can span 1342 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1343 // evaluate the condition. 1344 CFGBlock* ExitConditionBlock = createBlock(false); 1345 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1346 1347 // Set the terminator for the "exit" condition block. 1348 ExitConditionBlock->setTerminator(D); 1349 1350 // Now add the actual condition to the condition block. Because the condition 1351 // itself may contain control-flow, new blocks may be created. 1352 if (Stmt* C = D->getCond()) { 1353 Block = ExitConditionBlock; 1354 EntryConditionBlock = addStmt(C); 1355 if (Block) { 1356 if (!FinishBlock(EntryConditionBlock)) 1357 return 0; 1358 } 1359 } 1360 1361 // The condition block is the implicit successor for the loop body. 1362 Succ = EntryConditionBlock; 1363 1364 // See if this is a known constant. 1365 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1366 1367 // Process the loop body. 1368 CFGBlock* BodyBlock = NULL; 1369 { 1370 assert(D->getBody()); 1371 1372 // Save the current values for Block, Succ, and continue and break targets 1373 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1374 save_continue(ContinueTargetBlock), 1375 save_break(BreakTargetBlock); 1376 1377 // All continues within this loop should go to the condition block 1378 ContinueTargetBlock = EntryConditionBlock; 1379 1380 // All breaks should go to the code following the loop. 1381 BreakTargetBlock = LoopSuccessor; 1382 1383 // NULL out Block to force lazy instantiation of blocks for the body. 1384 Block = NULL; 1385 1386 // Create the body. The returned block is the entry to the loop body. 1387 BodyBlock = addStmt(D->getBody()); 1388 1389 if (!BodyBlock) 1390 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1391 else if (Block) { 1392 if (!FinishBlock(BodyBlock)) 1393 return 0; 1394 } 1395 1396 // Add an intermediate block between the BodyBlock and the 1397 // ExitConditionBlock to represent the "loop back" transition. Create an 1398 // empty block to represent the transition block for looping back to the 1399 // head of the loop. 1400 // FIXME: Can we do this more efficiently without adding another block? 1401 Block = NULL; 1402 Succ = BodyBlock; 1403 CFGBlock *LoopBackBlock = createBlock(); 1404 LoopBackBlock->setLoopTarget(D); 1405 1406 // Add the loop body entry as a successor to the condition. 1407 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : LoopBackBlock); 1408 } 1409 1410 // Link up the condition block with the code that follows the loop. 1411 // (the false branch). 1412 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1413 1414 // There can be no more statements in the body block(s) since we loop back to 1415 // the body. NULL out Block to force lazy creation of another block. 1416 Block = NULL; 1417 1418 // Return the loop body, which is the dominating block for the loop. 1419 Succ = BodyBlock; 1420 return BodyBlock; 1421} 1422 1423CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1424 // "continue" is a control-flow statement. Thus we stop processing the 1425 // current block. 1426 if (Block && !FinishBlock(Block)) 1427 return 0; 1428 1429 // Now create a new block that ends with the continue statement. 1430 Block = createBlock(false); 1431 Block->setTerminator(C); 1432 1433 // If there is no target for the continue, then we are looking at an 1434 // incomplete AST. This means the CFG cannot be constructed. 1435 if (ContinueTargetBlock) 1436 AddSuccessor(Block, ContinueTargetBlock); 1437 else 1438 badCFG = true; 1439 1440 return Block; 1441} 1442 1443CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1444 AddStmtChoice asc) { 1445 1446 if (asc.alwaysAdd()) { 1447 autoCreateBlock(); 1448 AppendStmt(Block, E); 1449 } 1450 1451 // VLA types have expressions that must be evaluated. 1452 if (E->isArgumentType()) { 1453 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1454 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1455 addStmt(VA->getSizeExpr()); 1456 } 1457 1458 return Block; 1459} 1460 1461/// VisitStmtExpr - Utility method to handle (nested) statement 1462/// expressions (a GCC extension). 1463CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 1464 if (asc.alwaysAdd()) { 1465 autoCreateBlock(); 1466 AppendStmt(Block, SE); 1467 } 1468 return VisitCompoundStmt(SE->getSubStmt()); 1469} 1470 1471CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1472 // "switch" is a control-flow statement. Thus we stop processing the current 1473 // block. 1474 CFGBlock* SwitchSuccessor = NULL; 1475 1476 if (Block) { 1477 if (!FinishBlock(Block)) 1478 return 0; 1479 SwitchSuccessor = Block; 1480 } else SwitchSuccessor = Succ; 1481 1482 // Save the current "switch" context. 1483 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1484 save_break(BreakTargetBlock), 1485 save_default(DefaultCaseBlock); 1486 1487 // Set the "default" case to be the block after the switch statement. If the 1488 // switch statement contains a "default:", this value will be overwritten with 1489 // the block for that code. 1490 DefaultCaseBlock = SwitchSuccessor; 1491 1492 // Create a new block that will contain the switch statement. 1493 SwitchTerminatedBlock = createBlock(false); 1494 1495 // Now process the switch body. The code after the switch is the implicit 1496 // successor. 1497 Succ = SwitchSuccessor; 1498 BreakTargetBlock = SwitchSuccessor; 1499 1500 // When visiting the body, the case statements should automatically get linked 1501 // up to the switch. We also don't keep a pointer to the body, since all 1502 // control-flow from the switch goes to case/default statements. 1503 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 1504 Block = NULL; 1505 CFGBlock *BodyBlock = addStmt(Terminator->getBody()); 1506 if (Block) { 1507 if (!FinishBlock(BodyBlock)) 1508 return 0; 1509 } 1510 1511 // If we have no "default:" case, the default transition is to the code 1512 // following the switch body. 1513 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1514 1515 // Add the terminator and condition in the switch block. 1516 SwitchTerminatedBlock->setTerminator(Terminator); 1517 assert(Terminator->getCond() && "switch condition must be non-NULL"); 1518 Block = SwitchTerminatedBlock; 1519 Block = addStmt(Terminator->getCond()); 1520 1521 // Finally, if the SwitchStmt contains a condition variable, add both the 1522 // SwitchStmt and the condition variable initialization to the CFG. 1523 if (VarDecl *VD = Terminator->getConditionVariable()) { 1524 if (Expr *Init = VD->getInit()) { 1525 autoCreateBlock(); 1526 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 1527 addStmt(Init); 1528 } 1529 } 1530 1531 return Block; 1532} 1533 1534CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1535 // CaseStmts are essentially labels, so they are the first statement in a 1536 // block. 1537 1538 if (CS->getSubStmt()) 1539 addStmt(CS->getSubStmt()); 1540 1541 CFGBlock* CaseBlock = Block; 1542 if (!CaseBlock) 1543 CaseBlock = createBlock(); 1544 1545 // Cases statements partition blocks, so this is the top of the basic block we 1546 // were processing (the "case XXX:" is the label). 1547 CaseBlock->setLabel(CS); 1548 1549 if (!FinishBlock(CaseBlock)) 1550 return 0; 1551 1552 // Add this block to the list of successors for the block with the switch 1553 // statement. 1554 assert(SwitchTerminatedBlock); 1555 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 1556 1557 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1558 Block = NULL; 1559 1560 // This block is now the implicit successor of other blocks. 1561 Succ = CaseBlock; 1562 1563 return CaseBlock; 1564} 1565 1566CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 1567 if (Terminator->getSubStmt()) 1568 addStmt(Terminator->getSubStmt()); 1569 1570 DefaultCaseBlock = Block; 1571 1572 if (!DefaultCaseBlock) 1573 DefaultCaseBlock = createBlock(); 1574 1575 // Default statements partition blocks, so this is the top of the basic block 1576 // we were processing (the "default:" is the label). 1577 DefaultCaseBlock->setLabel(Terminator); 1578 1579 if (!FinishBlock(DefaultCaseBlock)) 1580 return 0; 1581 1582 // Unlike case statements, we don't add the default block to the successors 1583 // for the switch statement immediately. This is done when we finish 1584 // processing the switch statement. This allows for the default case 1585 // (including a fall-through to the code after the switch statement) to always 1586 // be the last successor of a switch-terminated block. 1587 1588 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1589 Block = NULL; 1590 1591 // This block is now the implicit successor of other blocks. 1592 Succ = DefaultCaseBlock; 1593 1594 return DefaultCaseBlock; 1595} 1596 1597CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 1598 // "try"/"catch" is a control-flow statement. Thus we stop processing the 1599 // current block. 1600 CFGBlock* TrySuccessor = NULL; 1601 1602 if (Block) { 1603 if (!FinishBlock(Block)) 1604 return 0; 1605 TrySuccessor = Block; 1606 } else TrySuccessor = Succ; 1607 1608 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 1609 1610 // Create a new block that will contain the try statement. 1611 CFGBlock *NewTryTerminatedBlock = createBlock(false); 1612 // Add the terminator in the try block. 1613 NewTryTerminatedBlock->setTerminator(Terminator); 1614 1615 bool HasCatchAll = false; 1616 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 1617 // The code after the try is the implicit successor. 1618 Succ = TrySuccessor; 1619 CXXCatchStmt *CS = Terminator->getHandler(h); 1620 if (CS->getExceptionDecl() == 0) { 1621 HasCatchAll = true; 1622 } 1623 Block = NULL; 1624 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 1625 if (CatchBlock == 0) 1626 return 0; 1627 // Add this block to the list of successors for the block with the try 1628 // statement. 1629 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 1630 } 1631 if (!HasCatchAll) { 1632 if (PrevTryTerminatedBlock) 1633 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 1634 else 1635 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 1636 } 1637 1638 // The code after the try is the implicit successor. 1639 Succ = TrySuccessor; 1640 1641 // Save the current "try" context. 1642 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 1643 TryTerminatedBlock = NewTryTerminatedBlock; 1644 1645 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 1646 Block = NULL; 1647 Block = addStmt(Terminator->getTryBlock()); 1648 return Block; 1649} 1650 1651CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 1652 // CXXCatchStmt are treated like labels, so they are the first statement in a 1653 // block. 1654 1655 if (CS->getHandlerBlock()) 1656 addStmt(CS->getHandlerBlock()); 1657 1658 CFGBlock* CatchBlock = Block; 1659 if (!CatchBlock) 1660 CatchBlock = createBlock(); 1661 1662 CatchBlock->setLabel(CS); 1663 1664 if (!FinishBlock(CatchBlock)) 1665 return 0; 1666 1667 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1668 Block = NULL; 1669 1670 return CatchBlock; 1671} 1672 1673CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1674 // Lazily create the indirect-goto dispatch block if there isn't one already. 1675 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 1676 1677 if (!IBlock) { 1678 IBlock = createBlock(false); 1679 cfg->setIndirectGotoBlock(IBlock); 1680 } 1681 1682 // IndirectGoto is a control-flow statement. Thus we stop processing the 1683 // current block and create a new one. 1684 if (Block && !FinishBlock(Block)) 1685 return 0; 1686 1687 Block = createBlock(false); 1688 Block->setTerminator(I); 1689 AddSuccessor(Block, IBlock); 1690 return addStmt(I->getTarget()); 1691} 1692 1693} // end anonymous namespace 1694 1695/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 1696/// no successors or predecessors. If this is the first block created in the 1697/// CFG, it is automatically set to be the Entry and Exit of the CFG. 1698CFGBlock* CFG::createBlock() { 1699 bool first_block = begin() == end(); 1700 1701 // Create the block. 1702 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 1703 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 1704 Blocks.push_back(Mem, BlkBVC); 1705 1706 // If this is the first block, set it as the Entry and Exit. 1707 if (first_block) 1708 Entry = Exit = &back(); 1709 1710 // Return the block. 1711 return &back(); 1712} 1713 1714/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 1715/// CFG is returned to the caller. 1716CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 1717 bool AddScopes) { 1718 CFGBuilder Builder; 1719 return Builder.buildCFG(D, Statement, C, AddScopes); 1720} 1721 1722//===----------------------------------------------------------------------===// 1723// CFG: Queries for BlkExprs. 1724//===----------------------------------------------------------------------===// 1725 1726namespace { 1727 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 1728} 1729 1730static void FindSubExprAssignments(Stmt *S, 1731 llvm::SmallPtrSet<Expr*,50>& Set) { 1732 if (!S) 1733 return; 1734 1735 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 1736 Stmt *child = *I; 1737 if (!child) 1738 continue; 1739 1740 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 1741 if (B->isAssignmentOp()) Set.insert(B); 1742 1743 FindSubExprAssignments(child, Set); 1744 } 1745} 1746 1747static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 1748 BlkExprMapTy* M = new BlkExprMapTy(); 1749 1750 // Look for assignments that are used as subexpressions. These are the only 1751 // assignments that we want to *possibly* register as a block-level 1752 // expression. Basically, if an assignment occurs both in a subexpression and 1753 // at the block-level, it is a block-level expression. 1754 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 1755 1756 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 1757 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1758 FindSubExprAssignments(*BI, SubExprAssignments); 1759 1760 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 1761 1762 // Iterate over the statements again on identify the Expr* and Stmt* at the 1763 // block-level that are block-level expressions. 1764 1765 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1766 if (Expr* Exp = dyn_cast<Expr>(*BI)) { 1767 1768 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 1769 // Assignment expressions that are not nested within another 1770 // expression are really "statements" whose value is never used by 1771 // another expression. 1772 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 1773 continue; 1774 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 1775 // Special handling for statement expressions. The last statement in 1776 // the statement expression is also a block-level expr. 1777 const CompoundStmt* C = Terminator->getSubStmt(); 1778 if (!C->body_empty()) { 1779 unsigned x = M->size(); 1780 (*M)[C->body_back()] = x; 1781 } 1782 } 1783 1784 unsigned x = M->size(); 1785 (*M)[Exp] = x; 1786 } 1787 1788 // Look at terminators. The condition is a block-level expression. 1789 1790 Stmt* S = (*I)->getTerminatorCondition(); 1791 1792 if (S && M->find(S) == M->end()) { 1793 unsigned x = M->size(); 1794 (*M)[S] = x; 1795 } 1796 } 1797 1798 return M; 1799} 1800 1801CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 1802 assert(S != NULL); 1803 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 1804 1805 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 1806 BlkExprMapTy::iterator I = M->find(S); 1807 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 1808} 1809 1810unsigned CFG::getNumBlkExprs() { 1811 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 1812 return M->size(); 1813 else { 1814 // We assume callers interested in the number of BlkExprs will want 1815 // the map constructed if it doesn't already exist. 1816 BlkExprMap = (void*) PopulateBlkExprMap(*this); 1817 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 1818 } 1819} 1820 1821//===----------------------------------------------------------------------===// 1822// Cleanup: CFG dstor. 1823//===----------------------------------------------------------------------===// 1824 1825CFG::~CFG() { 1826 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 1827} 1828 1829//===----------------------------------------------------------------------===// 1830// CFG pretty printing 1831//===----------------------------------------------------------------------===// 1832 1833namespace { 1834 1835class StmtPrinterHelper : public PrinterHelper { 1836 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 1837 StmtMapTy StmtMap; 1838 signed CurrentBlock; 1839 unsigned CurrentStmt; 1840 const LangOptions &LangOpts; 1841public: 1842 1843 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 1844 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 1845 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 1846 unsigned j = 1; 1847 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 1848 BI != BEnd; ++BI, ++j ) 1849 StmtMap[*BI] = std::make_pair((*I)->getBlockID(),j); 1850 } 1851 } 1852 1853 virtual ~StmtPrinterHelper() {} 1854 1855 const LangOptions &getLangOpts() const { return LangOpts; } 1856 void setBlockID(signed i) { CurrentBlock = i; } 1857 void setStmtID(unsigned i) { CurrentStmt = i; } 1858 1859 virtual bool handledStmt(Stmt* Terminator, llvm::raw_ostream& OS) { 1860 1861 StmtMapTy::iterator I = StmtMap.find(Terminator); 1862 1863 if (I == StmtMap.end()) 1864 return false; 1865 1866 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 1867 && I->second.second == CurrentStmt) { 1868 return false; 1869 } 1870 1871 OS << "[B" << I->second.first << "." << I->second.second << "]"; 1872 return true; 1873 } 1874}; 1875} // end anonymous namespace 1876 1877 1878namespace { 1879class CFGBlockTerminatorPrint 1880 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 1881 1882 llvm::raw_ostream& OS; 1883 StmtPrinterHelper* Helper; 1884 PrintingPolicy Policy; 1885public: 1886 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 1887 const PrintingPolicy &Policy) 1888 : OS(os), Helper(helper), Policy(Policy) {} 1889 1890 void VisitIfStmt(IfStmt* I) { 1891 OS << "if "; 1892 I->getCond()->printPretty(OS,Helper,Policy); 1893 } 1894 1895 // Default case. 1896 void VisitStmt(Stmt* Terminator) { 1897 Terminator->printPretty(OS, Helper, Policy); 1898 } 1899 1900 void VisitForStmt(ForStmt* F) { 1901 OS << "for (" ; 1902 if (F->getInit()) 1903 OS << "..."; 1904 OS << "; "; 1905 if (Stmt* C = F->getCond()) 1906 C->printPretty(OS, Helper, Policy); 1907 OS << "; "; 1908 if (F->getInc()) 1909 OS << "..."; 1910 OS << ")"; 1911 } 1912 1913 void VisitWhileStmt(WhileStmt* W) { 1914 OS << "while " ; 1915 if (Stmt* C = W->getCond()) 1916 C->printPretty(OS, Helper, Policy); 1917 } 1918 1919 void VisitDoStmt(DoStmt* D) { 1920 OS << "do ... while "; 1921 if (Stmt* C = D->getCond()) 1922 C->printPretty(OS, Helper, Policy); 1923 } 1924 1925 void VisitSwitchStmt(SwitchStmt* Terminator) { 1926 OS << "switch "; 1927 Terminator->getCond()->printPretty(OS, Helper, Policy); 1928 } 1929 1930 void VisitCXXTryStmt(CXXTryStmt* CS) { 1931 OS << "try ..."; 1932 } 1933 1934 void VisitConditionalOperator(ConditionalOperator* C) { 1935 C->getCond()->printPretty(OS, Helper, Policy); 1936 OS << " ? ... : ..."; 1937 } 1938 1939 void VisitChooseExpr(ChooseExpr* C) { 1940 OS << "__builtin_choose_expr( "; 1941 C->getCond()->printPretty(OS, Helper, Policy); 1942 OS << " )"; 1943 } 1944 1945 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1946 OS << "goto *"; 1947 I->getTarget()->printPretty(OS, Helper, Policy); 1948 } 1949 1950 void VisitBinaryOperator(BinaryOperator* B) { 1951 if (!B->isLogicalOp()) { 1952 VisitExpr(B); 1953 return; 1954 } 1955 1956 B->getLHS()->printPretty(OS, Helper, Policy); 1957 1958 switch (B->getOpcode()) { 1959 case BinaryOperator::LOr: 1960 OS << " || ..."; 1961 return; 1962 case BinaryOperator::LAnd: 1963 OS << " && ..."; 1964 return; 1965 default: 1966 assert(false && "Invalid logical operator."); 1967 } 1968 } 1969 1970 void VisitExpr(Expr* E) { 1971 E->printPretty(OS, Helper, Policy); 1972 } 1973}; 1974} // end anonymous namespace 1975 1976 1977static void print_stmt(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 1978 const CFGElement &E) { 1979 Stmt *Terminator = E; 1980 1981 if (E.asStartScope()) { 1982 OS << "start scope\n"; 1983 return; 1984 } 1985 if (E.asEndScope()) { 1986 OS << "end scope\n"; 1987 return; 1988 } 1989 1990 if (Helper) { 1991 // special printing for statement-expressions. 1992 if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) { 1993 CompoundStmt* Sub = SE->getSubStmt(); 1994 1995 if (Sub->child_begin() != Sub->child_end()) { 1996 OS << "({ ... ; "; 1997 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 1998 OS << " })\n"; 1999 return; 2000 } 2001 } 2002 2003 // special printing for comma expressions. 2004 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) { 2005 if (B->getOpcode() == BinaryOperator::Comma) { 2006 OS << "... , "; 2007 Helper->handledStmt(B->getRHS(),OS); 2008 OS << '\n'; 2009 return; 2010 } 2011 } 2012 } 2013 2014 Terminator->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2015 2016 // Expressions need a newline. 2017 if (isa<Expr>(Terminator)) OS << '\n'; 2018} 2019 2020static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2021 const CFGBlock& B, 2022 StmtPrinterHelper* Helper, bool print_edges) { 2023 2024 if (Helper) Helper->setBlockID(B.getBlockID()); 2025 2026 // Print the header. 2027 OS << "\n [ B" << B.getBlockID(); 2028 2029 if (&B == &cfg->getEntry()) 2030 OS << " (ENTRY) ]\n"; 2031 else if (&B == &cfg->getExit()) 2032 OS << " (EXIT) ]\n"; 2033 else if (&B == cfg->getIndirectGotoBlock()) 2034 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2035 else 2036 OS << " ]\n"; 2037 2038 // Print the label of this block. 2039 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2040 2041 if (print_edges) 2042 OS << " "; 2043 2044 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2045 OS << L->getName(); 2046 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2047 OS << "case "; 2048 C->getLHS()->printPretty(OS, Helper, 2049 PrintingPolicy(Helper->getLangOpts())); 2050 if (C->getRHS()) { 2051 OS << " ... "; 2052 C->getRHS()->printPretty(OS, Helper, 2053 PrintingPolicy(Helper->getLangOpts())); 2054 } 2055 } else if (isa<DefaultStmt>(Label)) 2056 OS << "default"; 2057 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2058 OS << "catch ("; 2059 if (CS->getExceptionDecl()) 2060 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2061 0); 2062 else 2063 OS << "..."; 2064 OS << ")"; 2065 2066 } else 2067 assert(false && "Invalid label statement in CFGBlock."); 2068 2069 OS << ":\n"; 2070 } 2071 2072 // Iterate through the statements in the block and print them. 2073 unsigned j = 1; 2074 2075 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2076 I != E ; ++I, ++j ) { 2077 2078 // Print the statement # in the basic block and the statement itself. 2079 if (print_edges) 2080 OS << " "; 2081 2082 OS << llvm::format("%3d", j) << ": "; 2083 2084 if (Helper) 2085 Helper->setStmtID(j); 2086 2087 print_stmt(OS,Helper,*I); 2088 } 2089 2090 // Print the terminator of this block. 2091 if (B.getTerminator()) { 2092 if (print_edges) 2093 OS << " "; 2094 2095 OS << " T: "; 2096 2097 if (Helper) Helper->setBlockID(-1); 2098 2099 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2100 PrintingPolicy(Helper->getLangOpts())); 2101 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2102 OS << '\n'; 2103 } 2104 2105 if (print_edges) { 2106 // Print the predecessors of this block. 2107 OS << " Predecessors (" << B.pred_size() << "):"; 2108 unsigned i = 0; 2109 2110 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2111 I != E; ++I, ++i) { 2112 2113 if (i == 8 || (i-8) == 0) 2114 OS << "\n "; 2115 2116 OS << " B" << (*I)->getBlockID(); 2117 } 2118 2119 OS << '\n'; 2120 2121 // Print the successors of this block. 2122 OS << " Successors (" << B.succ_size() << "):"; 2123 i = 0; 2124 2125 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2126 I != E; ++I, ++i) { 2127 2128 if (i == 8 || (i-8) % 10 == 0) 2129 OS << "\n "; 2130 2131 if (*I) 2132 OS << " B" << (*I)->getBlockID(); 2133 else 2134 OS << " NULL"; 2135 } 2136 2137 OS << '\n'; 2138 } 2139} 2140 2141 2142/// dump - A simple pretty printer of a CFG that outputs to stderr. 2143void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2144 2145/// print - A simple pretty printer of a CFG that outputs to an ostream. 2146void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2147 StmtPrinterHelper Helper(this, LO); 2148 2149 // Print the entry block. 2150 print_block(OS, this, getEntry(), &Helper, true); 2151 2152 // Iterate through the CFGBlocks and print them one by one. 2153 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2154 // Skip the entry block, because we already printed it. 2155 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2156 continue; 2157 2158 print_block(OS, this, **I, &Helper, true); 2159 } 2160 2161 // Print the exit block. 2162 print_block(OS, this, getExit(), &Helper, true); 2163 OS.flush(); 2164} 2165 2166/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2167void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2168 print(llvm::errs(), cfg, LO); 2169} 2170 2171/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2172/// Generally this will only be called from CFG::print. 2173void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2174 const LangOptions &LO) const { 2175 StmtPrinterHelper Helper(cfg, LO); 2176 print_block(OS, cfg, *this, &Helper, true); 2177} 2178 2179/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2180void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2181 const LangOptions &LO) const { 2182 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2183 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2184} 2185 2186Stmt* CFGBlock::getTerminatorCondition() { 2187 2188 if (!Terminator) 2189 return NULL; 2190 2191 Expr* E = NULL; 2192 2193 switch (Terminator->getStmtClass()) { 2194 default: 2195 break; 2196 2197 case Stmt::ForStmtClass: 2198 E = cast<ForStmt>(Terminator)->getCond(); 2199 break; 2200 2201 case Stmt::WhileStmtClass: 2202 E = cast<WhileStmt>(Terminator)->getCond(); 2203 break; 2204 2205 case Stmt::DoStmtClass: 2206 E = cast<DoStmt>(Terminator)->getCond(); 2207 break; 2208 2209 case Stmt::IfStmtClass: 2210 E = cast<IfStmt>(Terminator)->getCond(); 2211 break; 2212 2213 case Stmt::ChooseExprClass: 2214 E = cast<ChooseExpr>(Terminator)->getCond(); 2215 break; 2216 2217 case Stmt::IndirectGotoStmtClass: 2218 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2219 break; 2220 2221 case Stmt::SwitchStmtClass: 2222 E = cast<SwitchStmt>(Terminator)->getCond(); 2223 break; 2224 2225 case Stmt::ConditionalOperatorClass: 2226 E = cast<ConditionalOperator>(Terminator)->getCond(); 2227 break; 2228 2229 case Stmt::BinaryOperatorClass: // '&&' and '||' 2230 E = cast<BinaryOperator>(Terminator)->getLHS(); 2231 break; 2232 2233 case Stmt::ObjCForCollectionStmtClass: 2234 return Terminator; 2235 } 2236 2237 return E ? E->IgnoreParens() : NULL; 2238} 2239 2240bool CFGBlock::hasBinaryBranchTerminator() const { 2241 2242 if (!Terminator) 2243 return false; 2244 2245 Expr* E = NULL; 2246 2247 switch (Terminator->getStmtClass()) { 2248 default: 2249 return false; 2250 2251 case Stmt::ForStmtClass: 2252 case Stmt::WhileStmtClass: 2253 case Stmt::DoStmtClass: 2254 case Stmt::IfStmtClass: 2255 case Stmt::ChooseExprClass: 2256 case Stmt::ConditionalOperatorClass: 2257 case Stmt::BinaryOperatorClass: 2258 return true; 2259 } 2260 2261 return E ? E->IgnoreParens() : NULL; 2262} 2263 2264 2265//===----------------------------------------------------------------------===// 2266// CFG Graphviz Visualization 2267//===----------------------------------------------------------------------===// 2268 2269 2270#ifndef NDEBUG 2271static StmtPrinterHelper* GraphHelper; 2272#endif 2273 2274void CFG::viewCFG(const LangOptions &LO) const { 2275#ifndef NDEBUG 2276 StmtPrinterHelper H(this, LO); 2277 GraphHelper = &H; 2278 llvm::ViewGraph(this,"CFG"); 2279 GraphHelper = NULL; 2280#endif 2281} 2282 2283namespace llvm { 2284template<> 2285struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2286 2287 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2288 2289 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 2290 2291#ifndef NDEBUG 2292 std::string OutSStr; 2293 llvm::raw_string_ostream Out(OutSStr); 2294 print_block(Out,Graph, *Node, GraphHelper, false); 2295 std::string& OutStr = Out.str(); 2296 2297 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2298 2299 // Process string output to make it nicer... 2300 for (unsigned i = 0; i != OutStr.length(); ++i) 2301 if (OutStr[i] == '\n') { // Left justify 2302 OutStr[i] = '\\'; 2303 OutStr.insert(OutStr.begin()+i+1, 'l'); 2304 } 2305 2306 return OutStr; 2307#else 2308 return ""; 2309#endif 2310 } 2311}; 2312} // end namespace llvm 2313