CFG.cpp revision a83dd9ed416916d004d30a2e1e9ecbc34f81c3ac
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/StmtVisitor.h" 18#include "clang/AST/PrettyPrinter.h" 19#include "llvm/Support/GraphWriter.h" 20#include "llvm/Support/Allocator.h" 21#include "llvm/Support/Format.h" 22#include "llvm/ADT/DenseMap.h" 23#include "llvm/ADT/SmallPtrSet.h" 24#include "llvm/ADT/OwningPtr.h" 25 26using namespace clang; 27 28namespace { 29 30static SourceLocation GetEndLoc(Decl* D) { 31 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 32 if (Expr* Ex = VD->getInit()) 33 return Ex->getSourceRange().getEnd(); 34 35 return D->getLocation(); 36} 37 38/// CFGBuilder - This class implements CFG construction from an AST. 39/// The builder is stateful: an instance of the builder should be used to only 40/// construct a single CFG. 41/// 42/// Example usage: 43/// 44/// CFGBuilder builder; 45/// CFG* cfg = builder.BuildAST(stmt1); 46/// 47/// CFG construction is done via a recursive walk of an AST. We actually parse 48/// the AST in reverse order so that the successor of a basic block is 49/// constructed prior to its predecessor. This allows us to nicely capture 50/// implicit fall-throughs without extra basic blocks. 51/// 52class CFGBuilder { 53 ASTContext *Context; 54 llvm::OwningPtr<CFG> cfg; 55 56 CFGBlock* Block; 57 CFGBlock* Succ; 58 CFGBlock* ContinueTargetBlock; 59 CFGBlock* BreakTargetBlock; 60 CFGBlock* SwitchTerminatedBlock; 61 CFGBlock* DefaultCaseBlock; 62 63 // LabelMap records the mapping from Label expressions to their blocks. 64 typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy; 65 LabelMapTy LabelMap; 66 67 // A list of blocks that end with a "goto" that must be backpatched to their 68 // resolved targets upon completion of CFG construction. 69 typedef std::vector<CFGBlock*> BackpatchBlocksTy; 70 BackpatchBlocksTy BackpatchBlocks; 71 72 // A list of labels whose address has been taken (for indirect gotos). 73 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 74 LabelSetTy AddressTakenLabels; 75 76public: 77 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 78 Block(NULL), Succ(NULL), 79 ContinueTargetBlock(NULL), BreakTargetBlock(NULL), 80 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL) {} 81 82 // buildCFG - Used by external clients to construct the CFG. 83 CFG* buildCFG(Stmt *Statement, ASTContext *C); 84 85private: 86 // Visitors to walk an AST and construct the CFG. 87 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, bool alwaysAdd); 88 CFGBlock *VisitBinaryOperator(BinaryOperator *B, bool alwaysAdd); 89 CFGBlock *VisitBlockExpr(BlockExpr* E, bool alwaysAdd); 90 CFGBlock *VisitBreakStmt(BreakStmt *B); 91 CFGBlock *VisitCallExpr(CallExpr *C, bool alwaysAdd); 92 CFGBlock *VisitCaseStmt(CaseStmt *C); 93 CFGBlock *VisitChooseExpr(ChooseExpr *C); 94 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 95 CFGBlock *VisitConditionalOperator(ConditionalOperator *C); 96 CFGBlock *VisitContinueStmt(ContinueStmt *C); 97 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 98 CFGBlock *VisitDeclStmt(DeclStmt *DS); 99 CFGBlock *VisitDeclSubExpr(Decl* D); 100 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 101 CFGBlock *VisitDoStmt(DoStmt *D); 102 CFGBlock *VisitForStmt(ForStmt *F); 103 CFGBlock *VisitGotoStmt(GotoStmt* G); 104 CFGBlock *VisitIfStmt(IfStmt *I); 105 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 106 CFGBlock *VisitLabelStmt(LabelStmt *L); 107 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 108 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 109 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 110 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 111 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 112 CFGBlock *VisitReturnStmt(ReturnStmt* R); 113 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, bool alwaysAdd); 114 CFGBlock *VisitStmtExpr(StmtExpr *S, bool alwaysAdd); 115 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 116 CFGBlock *VisitWhileStmt(WhileStmt *W); 117 118 CFGBlock *Visit(Stmt *S, bool alwaysAdd = false); 119 CFGBlock *VisitStmt(Stmt *S, bool alwaysAdd); 120 CFGBlock *VisitChildren(Stmt* S); 121 122 // NYS == Not Yet Supported 123 CFGBlock* NYS() { 124 badCFG = true; 125 return Block; 126 } 127 128 void autoCreateBlock() { if (!Block) Block = createBlock(); } 129 CFGBlock *createBlock(bool add_successor = true); 130 bool FinishBlock(CFGBlock* B); 131 CFGBlock *addStmt(Stmt *S) { return Visit(S, true); } 132 133 void AppendStmt(CFGBlock *B, Stmt *S) { 134 B->appendStmt(S, cfg->getBumpVectorContext()); 135 } 136 137 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 138 B->addSuccessor(S, cfg->getBumpVectorContext()); 139 } 140 141 /// TryResult - a class representing a variant over the values 142 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 143 /// and is used by the CFGBuilder to decide if a branch condition 144 /// can be decided up front during CFG construction. 145 class TryResult { 146 int X; 147 public: 148 TryResult(bool b) : X(b ? 1 : 0) {} 149 TryResult() : X(-1) {} 150 151 bool isTrue() const { return X == 1; } 152 bool isFalse() const { return X == 0; } 153 bool isKnown() const { return X >= 0; } 154 void negate() { 155 assert(isKnown()); 156 X ^= 0x1; 157 } 158 }; 159 160 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 161 /// if we can evaluate to a known value, otherwise return -1. 162 TryResult TryEvaluateBool(Expr *S) { 163 Expr::EvalResult Result; 164 if (!S->isTypeDependent() && !S->isValueDependent() && 165 S->Evaluate(Result, *Context) && Result.Val.isInt()) 166 return Result.Val.getInt().getBoolValue(); 167 168 return TryResult(); 169 } 170 171 bool badCFG; 172}; 173 174// FIXME: Add support for dependent-sized array types in C++? 175// Does it even make sense to build a CFG for an uninstantiated template? 176static VariableArrayType* FindVA(Type* t) { 177 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 178 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 179 if (vat->getSizeExpr()) 180 return vat; 181 182 t = vt->getElementType().getTypePtr(); 183 } 184 185 return 0; 186} 187 188/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 189/// arbitrary statement. Examples include a single expression or a function 190/// body (compound statement). The ownership of the returned CFG is 191/// transferred to the caller. If CFG construction fails, this method returns 192/// NULL. 193CFG* CFGBuilder::buildCFG(Stmt* Statement, ASTContext* C) { 194 Context = C; 195 assert(cfg.get()); 196 if (!Statement) 197 return NULL; 198 199 badCFG = false; 200 201 // Create an empty block that will serve as the exit block for the CFG. Since 202 // this is the first block added to the CFG, it will be implicitly registered 203 // as the exit block. 204 Succ = createBlock(); 205 assert(Succ == &cfg->getExit()); 206 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 207 208 // Visit the statements and create the CFG. 209 CFGBlock* B = addStmt(Statement); 210 if (!B) 211 B = Succ; 212 213 if (B) { 214 // Finalize the last constructed block. This usually involves reversing the 215 // order of the statements in the block. 216 if (Block) FinishBlock(B); 217 218 // Backpatch the gotos whose label -> block mappings we didn't know when we 219 // encountered them. 220 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 221 E = BackpatchBlocks.end(); I != E; ++I ) { 222 223 CFGBlock* B = *I; 224 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 225 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 226 227 // If there is no target for the goto, then we are looking at an 228 // incomplete AST. Handle this by not registering a successor. 229 if (LI == LabelMap.end()) continue; 230 231 AddSuccessor(B, LI->second); 232 } 233 234 // Add successors to the Indirect Goto Dispatch block (if we have one). 235 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 236 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 237 E = AddressTakenLabels.end(); I != E; ++I ) { 238 239 // Lookup the target block. 240 LabelMapTy::iterator LI = LabelMap.find(*I); 241 242 // If there is no target block that contains label, then we are looking 243 // at an incomplete AST. Handle this by not registering a successor. 244 if (LI == LabelMap.end()) continue; 245 246 AddSuccessor(B, LI->second); 247 } 248 249 Succ = B; 250 } 251 252 // Create an empty entry block that has no predecessors. 253 cfg->setEntry(createBlock()); 254 255 return badCFG ? NULL : cfg.take(); 256} 257 258/// createBlock - Used to lazily create blocks that are connected 259/// to the current (global) succcessor. 260CFGBlock* CFGBuilder::createBlock(bool add_successor) { 261 CFGBlock* B = cfg->createBlock(); 262 if (add_successor && Succ) 263 AddSuccessor(B, Succ); 264 return B; 265} 266 267/// FinishBlock - "Finalize" the block by checking if we have a bad CFG. 268bool CFGBuilder::FinishBlock(CFGBlock* B) { 269 if (badCFG) 270 return false; 271 272 assert(B); 273 return true; 274} 275 276/// Visit - Walk the subtree of a statement and add extra 277/// blocks for ternary operators, &&, and ||. We also process "," and 278/// DeclStmts (which may contain nested control-flow). 279CFGBlock* CFGBuilder::Visit(Stmt * S, bool alwaysAdd) { 280tryAgain: 281 switch (S->getStmtClass()) { 282 default: 283 return VisitStmt(S, alwaysAdd); 284 285 case Stmt::AddrLabelExprClass: 286 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), alwaysAdd); 287 288 case Stmt::BinaryOperatorClass: 289 return VisitBinaryOperator(cast<BinaryOperator>(S), alwaysAdd); 290 291 case Stmt::BlockExprClass: 292 return VisitBlockExpr(cast<BlockExpr>(S), alwaysAdd); 293 294 case Stmt::BreakStmtClass: 295 return VisitBreakStmt(cast<BreakStmt>(S)); 296 297 case Stmt::CallExprClass: 298 return VisitCallExpr(cast<CallExpr>(S), alwaysAdd); 299 300 case Stmt::CaseStmtClass: 301 return VisitCaseStmt(cast<CaseStmt>(S)); 302 303 case Stmt::ChooseExprClass: 304 return VisitChooseExpr(cast<ChooseExpr>(S)); 305 306 case Stmt::CompoundStmtClass: 307 return VisitCompoundStmt(cast<CompoundStmt>(S)); 308 309 case Stmt::ConditionalOperatorClass: 310 return VisitConditionalOperator(cast<ConditionalOperator>(S)); 311 312 case Stmt::ContinueStmtClass: 313 return VisitContinueStmt(cast<ContinueStmt>(S)); 314 315 case Stmt::DeclStmtClass: 316 return VisitDeclStmt(cast<DeclStmt>(S)); 317 318 case Stmt::DefaultStmtClass: 319 return VisitDefaultStmt(cast<DefaultStmt>(S)); 320 321 case Stmt::DoStmtClass: 322 return VisitDoStmt(cast<DoStmt>(S)); 323 324 case Stmt::ForStmtClass: 325 return VisitForStmt(cast<ForStmt>(S)); 326 327 case Stmt::GotoStmtClass: 328 return VisitGotoStmt(cast<GotoStmt>(S)); 329 330 case Stmt::IfStmtClass: 331 return VisitIfStmt(cast<IfStmt>(S)); 332 333 case Stmt::IndirectGotoStmtClass: 334 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 335 336 case Stmt::LabelStmtClass: 337 return VisitLabelStmt(cast<LabelStmt>(S)); 338 339 case Stmt::ObjCAtCatchStmtClass: 340 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 341 342 case Stmt::CXXThrowExprClass: 343 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 344 345 case Stmt::ObjCAtSynchronizedStmtClass: 346 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 347 348 case Stmt::ObjCAtThrowStmtClass: 349 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 350 351 case Stmt::ObjCAtTryStmtClass: 352 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 353 354 case Stmt::ObjCForCollectionStmtClass: 355 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 356 357 case Stmt::ParenExprClass: 358 S = cast<ParenExpr>(S)->getSubExpr(); 359 goto tryAgain; 360 361 case Stmt::NullStmtClass: 362 return Block; 363 364 case Stmt::ReturnStmtClass: 365 return VisitReturnStmt(cast<ReturnStmt>(S)); 366 367 case Stmt::SizeOfAlignOfExprClass: 368 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), alwaysAdd); 369 370 case Stmt::StmtExprClass: 371 return VisitStmtExpr(cast<StmtExpr>(S), alwaysAdd); 372 373 case Stmt::SwitchStmtClass: 374 return VisitSwitchStmt(cast<SwitchStmt>(S)); 375 376 case Stmt::WhileStmtClass: 377 return VisitWhileStmt(cast<WhileStmt>(S)); 378 } 379} 380 381CFGBlock *CFGBuilder::VisitStmt(Stmt *S, bool alwaysAdd) { 382 if (alwaysAdd) { 383 autoCreateBlock(); 384 AppendStmt(Block, S); 385 } 386 387 return VisitChildren(S); 388} 389 390/// VisitChildren - Visit the children of a Stmt. 391CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 392 CFGBlock *B = Block; 393 for (Stmt::child_iterator I = Terminator->child_begin(), 394 E = Terminator->child_end(); I != E; ++I) { 395 if (*I) B = Visit(*I); 396 } 397 return B; 398} 399 400CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, bool alwaysAdd) { 401 AddressTakenLabels.insert(A->getLabel()); 402 403 if (alwaysAdd) { 404 autoCreateBlock(); 405 AppendStmt(Block, A); 406 } 407 408 return Block; 409} 410 411CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, bool alwaysAdd) { 412 if (B->isLogicalOp()) { // && or || 413 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 414 AppendStmt(ConfluenceBlock, B); 415 416 if (!FinishBlock(ConfluenceBlock)) 417 return 0; 418 419 // create the block evaluating the LHS 420 CFGBlock* LHSBlock = createBlock(false); 421 LHSBlock->setTerminator(B); 422 423 // create the block evaluating the RHS 424 Succ = ConfluenceBlock; 425 Block = NULL; 426 CFGBlock* RHSBlock = addStmt(B->getRHS()); 427 if (!FinishBlock(RHSBlock)) 428 return 0; 429 430 // See if this is a known constant. 431 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 432 if (KnownVal.isKnown() && (B->getOpcode() == BinaryOperator::LOr)) 433 KnownVal.negate(); 434 435 // Now link the LHSBlock with RHSBlock. 436 if (B->getOpcode() == BinaryOperator::LOr) { 437 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 438 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 439 } else { 440 assert (B->getOpcode() == BinaryOperator::LAnd); 441 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 442 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 443 } 444 445 // Generate the blocks for evaluating the LHS. 446 Block = LHSBlock; 447 return addStmt(B->getLHS()); 448 } 449 else if (B->getOpcode() == BinaryOperator::Comma) { // , 450 autoCreateBlock(); 451 AppendStmt(Block, B); 452 addStmt(B->getRHS()); 453 return addStmt(B->getLHS()); 454 } 455 456 return VisitStmt(B, alwaysAdd); 457} 458 459CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, bool alwaysAdd) { 460 if (alwaysAdd) { 461 autoCreateBlock(); 462 AppendStmt(Block, E); 463 } 464 return Block; 465} 466 467CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 468 // "break" is a control-flow statement. Thus we stop processing the current 469 // block. 470 if (Block && !FinishBlock(Block)) 471 return 0; 472 473 // Now create a new block that ends with the break statement. 474 Block = createBlock(false); 475 Block->setTerminator(B); 476 477 // If there is no target for the break, then we are looking at an incomplete 478 // AST. This means that the CFG cannot be constructed. 479 if (BreakTargetBlock) 480 AddSuccessor(Block, BreakTargetBlock); 481 else 482 badCFG = true; 483 484 485 return Block; 486} 487 488CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, bool alwaysAdd) { 489 // If this is a call to a no-return function, this stops the block here. 490 bool NoReturn = false; 491 if (C->getCallee()->getType().getNoReturnAttr()) { 492 NoReturn = true; 493 } 494 495 if (FunctionDecl *FD = C->getDirectCallee()) 496 if (FD->hasAttr<NoReturnAttr>()) 497 NoReturn = true; 498 499 if (!NoReturn) 500 return VisitStmt(C, alwaysAdd); 501 502 if (Block && !FinishBlock(Block)) 503 return 0; 504 505 // Create new block with no successor for the remaining pieces. 506 Block = createBlock(false); 507 AppendStmt(Block, C); 508 509 // Wire this to the exit block directly. 510 AddSuccessor(Block, &cfg->getExit()); 511 512 return VisitChildren(C); 513} 514 515CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C) { 516 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 517 AppendStmt(ConfluenceBlock, C); 518 if (!FinishBlock(ConfluenceBlock)) 519 return 0; 520 521 Succ = ConfluenceBlock; 522 Block = NULL; 523 CFGBlock* LHSBlock = addStmt(C->getLHS()); 524 if (!FinishBlock(LHSBlock)) 525 return 0; 526 527 Succ = ConfluenceBlock; 528 Block = NULL; 529 CFGBlock* RHSBlock = addStmt(C->getRHS()); 530 if (!FinishBlock(RHSBlock)) 531 return 0; 532 533 Block = createBlock(false); 534 // See if this is a known constant. 535 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 536 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 537 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 538 Block->setTerminator(C); 539 return addStmt(C->getCond()); 540} 541 542 543CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 544 CFGBlock* LastBlock = Block; 545 546 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 547 I != E; ++I ) { 548 LastBlock = addStmt(*I); 549 550 if (badCFG) 551 return NULL; 552 } 553 return LastBlock; 554} 555 556CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C) { 557 // Create the confluence block that will "merge" the results of the ternary 558 // expression. 559 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 560 AppendStmt(ConfluenceBlock, C); 561 if (!FinishBlock(ConfluenceBlock)) 562 return 0; 563 564 // Create a block for the LHS expression if there is an LHS expression. A 565 // GCC extension allows LHS to be NULL, causing the condition to be the 566 // value that is returned instead. 567 // e.g: x ?: y is shorthand for: x ? x : y; 568 Succ = ConfluenceBlock; 569 Block = NULL; 570 CFGBlock* LHSBlock = NULL; 571 if (C->getLHS()) { 572 LHSBlock = addStmt(C->getLHS()); 573 if (!FinishBlock(LHSBlock)) 574 return 0; 575 Block = NULL; 576 } 577 578 // Create the block for the RHS expression. 579 Succ = ConfluenceBlock; 580 CFGBlock* RHSBlock = addStmt(C->getRHS()); 581 if (!FinishBlock(RHSBlock)) 582 return 0; 583 584 // Create the block that will contain the condition. 585 Block = createBlock(false); 586 587 // See if this is a known constant. 588 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 589 if (LHSBlock) { 590 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 591 } else { 592 if (KnownVal.isFalse()) { 593 // If we know the condition is false, add NULL as the successor for 594 // the block containing the condition. In this case, the confluence 595 // block will have just one predecessor. 596 AddSuccessor(Block, 0); 597 assert(ConfluenceBlock->pred_size() == 1); 598 } else { 599 // If we have no LHS expression, add the ConfluenceBlock as a direct 600 // successor for the block containing the condition. Moreover, we need to 601 // reverse the order of the predecessors in the ConfluenceBlock because 602 // the RHSBlock will have been added to the succcessors already, and we 603 // want the first predecessor to the the block containing the expression 604 // for the case when the ternary expression evaluates to true. 605 AddSuccessor(Block, ConfluenceBlock); 606 assert(ConfluenceBlock->pred_size() == 2); 607 std::reverse(ConfluenceBlock->pred_begin(), 608 ConfluenceBlock->pred_end()); 609 } 610 } 611 612 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 613 Block->setTerminator(C); 614 return addStmt(C->getCond()); 615} 616 617CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 618 autoCreateBlock(); 619 620 if (DS->isSingleDecl()) { 621 AppendStmt(Block, DS); 622 return VisitDeclSubExpr(DS->getSingleDecl()); 623 } 624 625 CFGBlock *B = 0; 626 627 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 628 typedef llvm::SmallVector<Decl*,10> BufTy; 629 BufTy Buf(DS->decl_begin(), DS->decl_end()); 630 631 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 632 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 633 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 634 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 635 636 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 637 // automatically freed with the CFG. 638 DeclGroupRef DG(*I); 639 Decl *D = *I; 640 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 641 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 642 643 // Append the fake DeclStmt to block. 644 AppendStmt(Block, DSNew); 645 B = VisitDeclSubExpr(D); 646 } 647 648 return B; 649} 650 651/// VisitDeclSubExpr - Utility method to add block-level expressions for 652/// initializers in Decls. 653CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 654 assert(Block); 655 656 VarDecl *VD = dyn_cast<VarDecl>(D); 657 658 if (!VD) 659 return Block; 660 661 Expr *Init = VD->getInit(); 662 663 if (Init) { 664 // Optimization: Don't create separate block-level statements for literals. 665 switch (Init->getStmtClass()) { 666 case Stmt::IntegerLiteralClass: 667 case Stmt::CharacterLiteralClass: 668 case Stmt::StringLiteralClass: 669 break; 670 default: 671 Block = addStmt(Init); 672 } 673 } 674 675 // If the type of VD is a VLA, then we must process its size expressions. 676 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 677 VA = FindVA(VA->getElementType().getTypePtr())) 678 Block = addStmt(VA->getSizeExpr()); 679 680 return Block; 681} 682 683CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 684 // We may see an if statement in the middle of a basic block, or it may be the 685 // first statement we are processing. In either case, we create a new basic 686 // block. First, we create the blocks for the then...else statements, and 687 // then we create the block containing the if statement. If we were in the 688 // middle of a block, we stop processing that block. That block is then the 689 // implicit successor for the "then" and "else" clauses. 690 691 // The block we were proccessing is now finished. Make it the successor 692 // block. 693 if (Block) { 694 Succ = Block; 695 if (!FinishBlock(Block)) 696 return 0; 697 } 698 699 // Process the false branch. 700 CFGBlock* ElseBlock = Succ; 701 702 if (Stmt* Else = I->getElse()) { 703 SaveAndRestore<CFGBlock*> sv(Succ); 704 705 // NULL out Block so that the recursive call to Visit will 706 // create a new basic block. 707 Block = NULL; 708 ElseBlock = addStmt(Else); 709 710 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 711 ElseBlock = sv.get(); 712 else if (Block) { 713 if (!FinishBlock(ElseBlock)) 714 return 0; 715 } 716 } 717 718 // Process the true branch. 719 CFGBlock* ThenBlock; 720 { 721 Stmt* Then = I->getThen(); 722 assert (Then); 723 SaveAndRestore<CFGBlock*> sv(Succ); 724 Block = NULL; 725 ThenBlock = addStmt(Then); 726 727 if (!ThenBlock) { 728 // We can reach here if the "then" body has all NullStmts. 729 // Create an empty block so we can distinguish between true and false 730 // branches in path-sensitive analyses. 731 ThenBlock = createBlock(false); 732 AddSuccessor(ThenBlock, sv.get()); 733 } else if (Block) { 734 if (!FinishBlock(ThenBlock)) 735 return 0; 736 } 737 } 738 739 // Now create a new block containing the if statement. 740 Block = createBlock(false); 741 742 // Set the terminator of the new block to the If statement. 743 Block->setTerminator(I); 744 745 // See if this is a known constant. 746 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 747 748 // Now add the successors. 749 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 750 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 751 752 // Add the condition as the last statement in the new block. This may create 753 // new blocks as the condition may contain control-flow. Any newly created 754 // blocks will be pointed to be "Block". 755 return addStmt(I->getCond()); 756} 757 758 759CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 760 // If we were in the middle of a block we stop processing that block. 761 // 762 // NOTE: If a "return" appears in the middle of a block, this means that the 763 // code afterwards is DEAD (unreachable). We still keep a basic block 764 // for that code; a simple "mark-and-sweep" from the entry block will be 765 // able to report such dead blocks. 766 if (Block) 767 FinishBlock(Block); 768 769 // Create the new block. 770 Block = createBlock(false); 771 772 // The Exit block is the only successor. 773 AddSuccessor(Block, &cfg->getExit()); 774 775 // Add the return statement to the block. This may create new blocks if R 776 // contains control-flow (short-circuit operations). 777 return VisitStmt(R, true); 778} 779 780CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 781 // Get the block of the labeled statement. Add it to our map. 782 addStmt(L->getSubStmt()); 783 CFGBlock* LabelBlock = Block; 784 785 if (!LabelBlock) // This can happen when the body is empty, i.e. 786 LabelBlock = createBlock(); // scopes that only contains NullStmts. 787 788 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 789 LabelMap[ L ] = LabelBlock; 790 791 // Labels partition blocks, so this is the end of the basic block we were 792 // processing (L is the block's label). Because this is label (and we have 793 // already processed the substatement) there is no extra control-flow to worry 794 // about. 795 LabelBlock->setLabel(L); 796 if (!FinishBlock(LabelBlock)) 797 return 0; 798 799 // We set Block to NULL to allow lazy creation of a new block (if necessary); 800 Block = NULL; 801 802 // This block is now the implicit successor of other blocks. 803 Succ = LabelBlock; 804 805 return LabelBlock; 806} 807 808CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 809 // Goto is a control-flow statement. Thus we stop processing the current 810 // block and create a new one. 811 if (Block) 812 FinishBlock(Block); 813 814 Block = createBlock(false); 815 Block->setTerminator(G); 816 817 // If we already know the mapping to the label block add the successor now. 818 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 819 820 if (I == LabelMap.end()) 821 // We will need to backpatch this block later. 822 BackpatchBlocks.push_back(Block); 823 else 824 AddSuccessor(Block, I->second); 825 826 return Block; 827} 828 829CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 830 CFGBlock* LoopSuccessor = NULL; 831 832 // "for" is a control-flow statement. Thus we stop processing the current 833 // block. 834 if (Block) { 835 if (!FinishBlock(Block)) 836 return 0; 837 LoopSuccessor = Block; 838 } else 839 LoopSuccessor = Succ; 840 841 // Because of short-circuit evaluation, the condition of the loop can span 842 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 843 // evaluate the condition. 844 CFGBlock* ExitConditionBlock = createBlock(false); 845 CFGBlock* EntryConditionBlock = ExitConditionBlock; 846 847 // Set the terminator for the "exit" condition block. 848 ExitConditionBlock->setTerminator(F); 849 850 // Now add the actual condition to the condition block. Because the condition 851 // itself may contain control-flow, new blocks may be created. 852 if (Stmt* C = F->getCond()) { 853 Block = ExitConditionBlock; 854 EntryConditionBlock = addStmt(C); 855 if (Block) { 856 if (!FinishBlock(EntryConditionBlock)) 857 return 0; 858 } 859 } 860 861 // The condition block is the implicit successor for the loop body as well as 862 // any code above the loop. 863 Succ = EntryConditionBlock; 864 865 // See if this is a known constant. 866 TryResult KnownVal(true); 867 868 if (F->getCond()) 869 KnownVal = TryEvaluateBool(F->getCond()); 870 871 // Now create the loop body. 872 { 873 assert (F->getBody()); 874 875 // Save the current values for Block, Succ, and continue and break targets 876 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 877 save_continue(ContinueTargetBlock), 878 save_break(BreakTargetBlock); 879 880 // Create a new block to contain the (bottom) of the loop body. 881 Block = NULL; 882 883 if (Stmt* I = F->getInc()) { 884 // Generate increment code in its own basic block. This is the target of 885 // continue statements. 886 Succ = addStmt(I); 887 } else { 888 // No increment code. Create a special, empty, block that is used as the 889 // target block for "looping back" to the start of the loop. 890 assert(Succ == EntryConditionBlock); 891 Succ = createBlock(); 892 } 893 894 // Finish up the increment (or empty) block if it hasn't been already. 895 if (Block) { 896 assert(Block == Succ); 897 if (!FinishBlock(Block)) 898 return 0; 899 Block = 0; 900 } 901 902 ContinueTargetBlock = Succ; 903 904 // The starting block for the loop increment is the block that should 905 // represent the 'loop target' for looping back to the start of the loop. 906 ContinueTargetBlock->setLoopTarget(F); 907 908 // All breaks should go to the code following the loop. 909 BreakTargetBlock = LoopSuccessor; 910 911 // Now populate the body block, and in the process create new blocks as we 912 // walk the body of the loop. 913 CFGBlock* BodyBlock = addStmt(F->getBody()); 914 915 if (!BodyBlock) 916 BodyBlock = ContinueTargetBlock; // can happen for "for (...;...;...) ;" 917 else if (Block && !FinishBlock(BodyBlock)) 918 return 0; 919 920 // This new body block is a successor to our "exit" condition block. 921 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 922 } 923 924 // Link up the condition block with the code that follows the loop. (the 925 // false branch). 926 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 927 928 // If the loop contains initialization, create a new block for those 929 // statements. This block can also contain statements that precede the loop. 930 if (Stmt* I = F->getInit()) { 931 Block = createBlock(); 932 return addStmt(I); 933 } else { 934 // There is no loop initialization. We are thus basically a while loop. 935 // NULL out Block to force lazy block construction. 936 Block = NULL; 937 Succ = EntryConditionBlock; 938 return EntryConditionBlock; 939 } 940} 941 942CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 943 // Objective-C fast enumeration 'for' statements: 944 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 945 // 946 // for ( Type newVariable in collection_expression ) { statements } 947 // 948 // becomes: 949 // 950 // prologue: 951 // 1. collection_expression 952 // T. jump to loop_entry 953 // loop_entry: 954 // 1. side-effects of element expression 955 // 1. ObjCForCollectionStmt [performs binding to newVariable] 956 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 957 // TB: 958 // statements 959 // T. jump to loop_entry 960 // FB: 961 // what comes after 962 // 963 // and 964 // 965 // Type existingItem; 966 // for ( existingItem in expression ) { statements } 967 // 968 // becomes: 969 // 970 // the same with newVariable replaced with existingItem; the binding works 971 // the same except that for one ObjCForCollectionStmt::getElement() returns 972 // a DeclStmt and the other returns a DeclRefExpr. 973 // 974 975 CFGBlock* LoopSuccessor = 0; 976 977 if (Block) { 978 if (!FinishBlock(Block)) 979 return 0; 980 LoopSuccessor = Block; 981 Block = 0; 982 } else 983 LoopSuccessor = Succ; 984 985 // Build the condition blocks. 986 CFGBlock* ExitConditionBlock = createBlock(false); 987 CFGBlock* EntryConditionBlock = ExitConditionBlock; 988 989 // Set the terminator for the "exit" condition block. 990 ExitConditionBlock->setTerminator(S); 991 992 // The last statement in the block should be the ObjCForCollectionStmt, which 993 // performs the actual binding to 'element' and determines if there are any 994 // more items in the collection. 995 AppendStmt(ExitConditionBlock, S); 996 Block = ExitConditionBlock; 997 998 // Walk the 'element' expression to see if there are any side-effects. We 999 // generate new blocks as necesary. We DON'T add the statement by default to 1000 // the CFG unless it contains control-flow. 1001 EntryConditionBlock = Visit(S->getElement(), false); 1002 if (Block) { 1003 if (!FinishBlock(EntryConditionBlock)) 1004 return 0; 1005 Block = 0; 1006 } 1007 1008 // The condition block is the implicit successor for the loop body as well as 1009 // any code above the loop. 1010 Succ = EntryConditionBlock; 1011 1012 // Now create the true branch. 1013 { 1014 // Save the current values for Succ, continue and break targets. 1015 SaveAndRestore<CFGBlock*> save_Succ(Succ), 1016 save_continue(ContinueTargetBlock), save_break(BreakTargetBlock); 1017 1018 BreakTargetBlock = LoopSuccessor; 1019 ContinueTargetBlock = EntryConditionBlock; 1020 1021 CFGBlock* BodyBlock = addStmt(S->getBody()); 1022 1023 if (!BodyBlock) 1024 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1025 else if (Block) { 1026 if (!FinishBlock(BodyBlock)) 1027 return 0; 1028 } 1029 1030 // This new body block is a successor to our "exit" condition block. 1031 AddSuccessor(ExitConditionBlock, BodyBlock); 1032 } 1033 1034 // Link up the condition block with the code that follows the loop. 1035 // (the false branch). 1036 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1037 1038 // Now create a prologue block to contain the collection expression. 1039 Block = createBlock(); 1040 return addStmt(S->getCollection()); 1041} 1042 1043CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1044 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1045 1046 // Inline the body. 1047 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1048 1049 // The sync body starts its own basic block. This makes it a little easier 1050 // for diagnostic clients. 1051 if (SyncBlock) { 1052 if (!FinishBlock(SyncBlock)) 1053 return 0; 1054 1055 Block = 0; 1056 } 1057 1058 Succ = SyncBlock; 1059 1060 // Inline the sync expression. 1061 return addStmt(S->getSynchExpr()); 1062} 1063 1064CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1065 // FIXME 1066 return NYS(); 1067} 1068 1069CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1070 CFGBlock* LoopSuccessor = NULL; 1071 1072 // "while" is a control-flow statement. Thus we stop processing the current 1073 // block. 1074 if (Block) { 1075 if (!FinishBlock(Block)) 1076 return 0; 1077 LoopSuccessor = Block; 1078 } else 1079 LoopSuccessor = Succ; 1080 1081 // Because of short-circuit evaluation, the condition of the loop can span 1082 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1083 // evaluate the condition. 1084 CFGBlock* ExitConditionBlock = createBlock(false); 1085 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1086 1087 // Set the terminator for the "exit" condition block. 1088 ExitConditionBlock->setTerminator(W); 1089 1090 // Now add the actual condition to the condition block. Because the condition 1091 // itself may contain control-flow, new blocks may be created. Thus we update 1092 // "Succ" after adding the condition. 1093 if (Stmt* C = W->getCond()) { 1094 Block = ExitConditionBlock; 1095 EntryConditionBlock = addStmt(C); 1096 assert(Block == EntryConditionBlock); 1097 if (Block) { 1098 if (!FinishBlock(EntryConditionBlock)) 1099 return 0; 1100 } 1101 } 1102 1103 // The condition block is the implicit successor for the loop body as well as 1104 // any code above the loop. 1105 Succ = EntryConditionBlock; 1106 1107 // See if this is a known constant. 1108 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1109 1110 // Process the loop body. 1111 { 1112 assert(W->getBody()); 1113 1114 // Save the current values for Block, Succ, and continue and break targets 1115 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1116 save_continue(ContinueTargetBlock), 1117 save_break(BreakTargetBlock); 1118 1119 // Create an empty block to represent the transition block for looping back 1120 // to the head of the loop. 1121 Block = 0; 1122 assert(Succ == EntryConditionBlock); 1123 Succ = createBlock(); 1124 Succ->setLoopTarget(W); 1125 ContinueTargetBlock = Succ; 1126 1127 // All breaks should go to the code following the loop. 1128 BreakTargetBlock = LoopSuccessor; 1129 1130 // NULL out Block to force lazy instantiation of blocks for the body. 1131 Block = NULL; 1132 1133 // Create the body. The returned block is the entry to the loop body. 1134 CFGBlock* BodyBlock = addStmt(W->getBody()); 1135 1136 if (!BodyBlock) 1137 BodyBlock = ContinueTargetBlock; // can happen for "while(...) ;" 1138 else if (Block) { 1139 if (!FinishBlock(BodyBlock)) 1140 return 0; 1141 } 1142 1143 // Add the loop body entry as a successor to the condition. 1144 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1145 } 1146 1147 // Link up the condition block with the code that follows the loop. (the 1148 // false branch). 1149 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1150 1151 // There can be no more statements in the condition block since we loop back 1152 // to this block. NULL out Block to force lazy creation of another block. 1153 Block = NULL; 1154 1155 // Return the condition block, which is the dominating block for the loop. 1156 Succ = EntryConditionBlock; 1157 return EntryConditionBlock; 1158} 1159 1160 1161CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1162 // FIXME: For now we pretend that @catch and the code it contains does not 1163 // exit. 1164 return Block; 1165} 1166 1167CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1168 // FIXME: This isn't complete. We basically treat @throw like a return 1169 // statement. 1170 1171 // If we were in the middle of a block we stop processing that block. 1172 if (Block && !FinishBlock(Block)) 1173 return 0; 1174 1175 // Create the new block. 1176 Block = createBlock(false); 1177 1178 // The Exit block is the only successor. 1179 AddSuccessor(Block, &cfg->getExit()); 1180 1181 // Add the statement to the block. This may create new blocks if S contains 1182 // control-flow (short-circuit operations). 1183 return VisitStmt(S, true); 1184} 1185 1186CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1187 // If we were in the middle of a block we stop processing that block. 1188 if (Block && !FinishBlock(Block)) 1189 return 0; 1190 1191 // Create the new block. 1192 Block = createBlock(false); 1193 1194 // The Exit block is the only successor. 1195 AddSuccessor(Block, &cfg->getExit()); 1196 1197 // Add the statement to the block. This may create new blocks if S contains 1198 // control-flow (short-circuit operations). 1199 return VisitStmt(T, true); 1200} 1201 1202CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1203 CFGBlock* LoopSuccessor = NULL; 1204 1205 // "do...while" is a control-flow statement. Thus we stop processing the 1206 // current block. 1207 if (Block) { 1208 if (!FinishBlock(Block)) 1209 return 0; 1210 LoopSuccessor = Block; 1211 } else 1212 LoopSuccessor = Succ; 1213 1214 // Because of short-circuit evaluation, the condition of the loop can span 1215 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1216 // evaluate the condition. 1217 CFGBlock* ExitConditionBlock = createBlock(false); 1218 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1219 1220 // Set the terminator for the "exit" condition block. 1221 ExitConditionBlock->setTerminator(D); 1222 1223 // Now add the actual condition to the condition block. Because the condition 1224 // itself may contain control-flow, new blocks may be created. 1225 if (Stmt* C = D->getCond()) { 1226 Block = ExitConditionBlock; 1227 EntryConditionBlock = addStmt(C); 1228 if (Block) { 1229 if (!FinishBlock(EntryConditionBlock)) 1230 return 0; 1231 } 1232 } 1233 1234 // The condition block is the implicit successor for the loop body. 1235 Succ = EntryConditionBlock; 1236 1237 // See if this is a known constant. 1238 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1239 1240 // Process the loop body. 1241 CFGBlock* BodyBlock = NULL; 1242 { 1243 assert (D->getBody()); 1244 1245 // Save the current values for Block, Succ, and continue and break targets 1246 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1247 save_continue(ContinueTargetBlock), 1248 save_break(BreakTargetBlock); 1249 1250 // All continues within this loop should go to the condition block 1251 ContinueTargetBlock = EntryConditionBlock; 1252 1253 // All breaks should go to the code following the loop. 1254 BreakTargetBlock = LoopSuccessor; 1255 1256 // NULL out Block to force lazy instantiation of blocks for the body. 1257 Block = NULL; 1258 1259 // Create the body. The returned block is the entry to the loop body. 1260 BodyBlock = addStmt(D->getBody()); 1261 1262 if (!BodyBlock) 1263 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1264 else if (Block) { 1265 if (!FinishBlock(BodyBlock)) 1266 return 0; 1267 } 1268 1269 // Add an intermediate block between the BodyBlock and the 1270 // ExitConditionBlock to represent the "loop back" transition. Create an 1271 // empty block to represent the transition block for looping back to the 1272 // head of the loop. 1273 // FIXME: Can we do this more efficiently without adding another block? 1274 Block = NULL; 1275 Succ = BodyBlock; 1276 CFGBlock *LoopBackBlock = createBlock(); 1277 LoopBackBlock->setLoopTarget(D); 1278 1279 // Add the loop body entry as a successor to the condition. 1280 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : LoopBackBlock); 1281 } 1282 1283 // Link up the condition block with the code that follows the loop. 1284 // (the false branch). 1285 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1286 1287 // There can be no more statements in the body block(s) since we loop back to 1288 // the body. NULL out Block to force lazy creation of another block. 1289 Block = NULL; 1290 1291 // Return the loop body, which is the dominating block for the loop. 1292 Succ = BodyBlock; 1293 return BodyBlock; 1294} 1295 1296CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1297 // "continue" is a control-flow statement. Thus we stop processing the 1298 // current block. 1299 if (Block && !FinishBlock(Block)) 1300 return 0; 1301 1302 // Now create a new block that ends with the continue statement. 1303 Block = createBlock(false); 1304 Block->setTerminator(C); 1305 1306 // If there is no target for the continue, then we are looking at an 1307 // incomplete AST. This means the CFG cannot be constructed. 1308 if (ContinueTargetBlock) 1309 AddSuccessor(Block, ContinueTargetBlock); 1310 else 1311 badCFG = true; 1312 1313 return Block; 1314} 1315 1316CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1317 bool alwaysAdd) { 1318 1319 if (alwaysAdd) { 1320 autoCreateBlock(); 1321 AppendStmt(Block, E); 1322 } 1323 1324 // VLA types have expressions that must be evaluated. 1325 if (E->isArgumentType()) { 1326 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1327 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1328 addStmt(VA->getSizeExpr()); 1329 } 1330 1331 return Block; 1332} 1333 1334/// VisitStmtExpr - Utility method to handle (nested) statement 1335/// expressions (a GCC extension). 1336CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, bool alwaysAdd) { 1337 if (alwaysAdd) { 1338 autoCreateBlock(); 1339 AppendStmt(Block, SE); 1340 } 1341 return VisitCompoundStmt(SE->getSubStmt()); 1342} 1343 1344CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1345 // "switch" is a control-flow statement. Thus we stop processing the current 1346 // block. 1347 CFGBlock* SwitchSuccessor = NULL; 1348 1349 if (Block) { 1350 if (!FinishBlock(Block)) 1351 return 0; 1352 SwitchSuccessor = Block; 1353 } else SwitchSuccessor = Succ; 1354 1355 // Save the current "switch" context. 1356 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1357 save_break(BreakTargetBlock), 1358 save_default(DefaultCaseBlock); 1359 1360 // Set the "default" case to be the block after the switch statement. If the 1361 // switch statement contains a "default:", this value will be overwritten with 1362 // the block for that code. 1363 DefaultCaseBlock = SwitchSuccessor; 1364 1365 // Create a new block that will contain the switch statement. 1366 SwitchTerminatedBlock = createBlock(false); 1367 1368 // Now process the switch body. The code after the switch is the implicit 1369 // successor. 1370 Succ = SwitchSuccessor; 1371 BreakTargetBlock = SwitchSuccessor; 1372 1373 // When visiting the body, the case statements should automatically get linked 1374 // up to the switch. We also don't keep a pointer to the body, since all 1375 // control-flow from the switch goes to case/default statements. 1376 assert (Terminator->getBody() && "switch must contain a non-NULL body"); 1377 Block = NULL; 1378 CFGBlock *BodyBlock = addStmt(Terminator->getBody()); 1379 if (Block) { 1380 if (!FinishBlock(BodyBlock)) 1381 return 0; 1382 } 1383 1384 // If we have no "default:" case, the default transition is to the code 1385 // following the switch body. 1386 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1387 1388 // Add the terminator and condition in the switch block. 1389 SwitchTerminatedBlock->setTerminator(Terminator); 1390 assert (Terminator->getCond() && "switch condition must be non-NULL"); 1391 Block = SwitchTerminatedBlock; 1392 1393 return addStmt(Terminator->getCond()); 1394} 1395 1396CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1397 // CaseStmts are essentially labels, so they are the first statement in a 1398 // block. 1399 1400 if (CS->getSubStmt()) 1401 addStmt(CS->getSubStmt()); 1402 1403 CFGBlock* CaseBlock = Block; 1404 if (!CaseBlock) 1405 CaseBlock = createBlock(); 1406 1407 // Cases statements partition blocks, so this is the top of the basic block we 1408 // were processing (the "case XXX:" is the label). 1409 CaseBlock->setLabel(CS); 1410 1411 if (!FinishBlock(CaseBlock)) 1412 return 0; 1413 1414 // Add this block to the list of successors for the block with the switch 1415 // statement. 1416 assert(SwitchTerminatedBlock); 1417 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 1418 1419 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1420 Block = NULL; 1421 1422 // This block is now the implicit successor of other blocks. 1423 Succ = CaseBlock; 1424 1425 return CaseBlock; 1426} 1427 1428CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 1429 if (Terminator->getSubStmt()) 1430 addStmt(Terminator->getSubStmt()); 1431 1432 DefaultCaseBlock = Block; 1433 1434 if (!DefaultCaseBlock) 1435 DefaultCaseBlock = createBlock(); 1436 1437 // Default statements partition blocks, so this is the top of the basic block 1438 // we were processing (the "default:" is the label). 1439 DefaultCaseBlock->setLabel(Terminator); 1440 1441 if (!FinishBlock(DefaultCaseBlock)) 1442 return 0; 1443 1444 // Unlike case statements, we don't add the default block to the successors 1445 // for the switch statement immediately. This is done when we finish 1446 // processing the switch statement. This allows for the default case 1447 // (including a fall-through to the code after the switch statement) to always 1448 // be the last successor of a switch-terminated block. 1449 1450 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1451 Block = NULL; 1452 1453 // This block is now the implicit successor of other blocks. 1454 Succ = DefaultCaseBlock; 1455 1456 return DefaultCaseBlock; 1457} 1458 1459CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1460 // Lazily create the indirect-goto dispatch block if there isn't one already. 1461 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 1462 1463 if (!IBlock) { 1464 IBlock = createBlock(false); 1465 cfg->setIndirectGotoBlock(IBlock); 1466 } 1467 1468 // IndirectGoto is a control-flow statement. Thus we stop processing the 1469 // current block and create a new one. 1470 if (Block && !FinishBlock(Block)) 1471 return 0; 1472 1473 Block = createBlock(false); 1474 Block->setTerminator(I); 1475 AddSuccessor(Block, IBlock); 1476 return addStmt(I->getTarget()); 1477} 1478 1479} // end anonymous namespace 1480 1481/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 1482/// no successors or predecessors. If this is the first block created in the 1483/// CFG, it is automatically set to be the Entry and Exit of the CFG. 1484CFGBlock* CFG::createBlock() { 1485 bool first_block = begin() == end(); 1486 1487 // Create the block. 1488 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 1489 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 1490 Blocks.push_back(Mem, BlkBVC); 1491 1492 // If this is the first block, set it as the Entry and Exit. 1493 if (first_block) 1494 Entry = Exit = &back(); 1495 1496 // Return the block. 1497 return &back(); 1498} 1499 1500/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 1501/// CFG is returned to the caller. 1502CFG* CFG::buildCFG(Stmt* Statement, ASTContext *C) { 1503 CFGBuilder Builder; 1504 return Builder.buildCFG(Statement, C); 1505} 1506 1507//===----------------------------------------------------------------------===// 1508// CFG: Queries for BlkExprs. 1509//===----------------------------------------------------------------------===// 1510 1511namespace { 1512 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 1513} 1514 1515static void FindSubExprAssignments(Stmt* Terminator, llvm::SmallPtrSet<Expr*,50>& Set) { 1516 if (!Terminator) 1517 return; 1518 1519 for (Stmt::child_iterator I=Terminator->child_begin(), E=Terminator->child_end(); I!=E; ++I) { 1520 if (!*I) continue; 1521 1522 if (BinaryOperator* B = dyn_cast<BinaryOperator>(*I)) 1523 if (B->isAssignmentOp()) Set.insert(B); 1524 1525 FindSubExprAssignments(*I, Set); 1526 } 1527} 1528 1529static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 1530 BlkExprMapTy* M = new BlkExprMapTy(); 1531 1532 // Look for assignments that are used as subexpressions. These are the only 1533 // assignments that we want to *possibly* register as a block-level 1534 // expression. Basically, if an assignment occurs both in a subexpression and 1535 // at the block-level, it is a block-level expression. 1536 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 1537 1538 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 1539 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1540 FindSubExprAssignments(*BI, SubExprAssignments); 1541 1542 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 1543 1544 // Iterate over the statements again on identify the Expr* and Stmt* at the 1545 // block-level that are block-level expressions. 1546 1547 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1548 if (Expr* Exp = dyn_cast<Expr>(*BI)) { 1549 1550 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 1551 // Assignment expressions that are not nested within another 1552 // expression are really "statements" whose value is never used by 1553 // another expression. 1554 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 1555 continue; 1556 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 1557 // Special handling for statement expressions. The last statement in 1558 // the statement expression is also a block-level expr. 1559 const CompoundStmt* C = Terminator->getSubStmt(); 1560 if (!C->body_empty()) { 1561 unsigned x = M->size(); 1562 (*M)[C->body_back()] = x; 1563 } 1564 } 1565 1566 unsigned x = M->size(); 1567 (*M)[Exp] = x; 1568 } 1569 1570 // Look at terminators. The condition is a block-level expression. 1571 1572 Stmt* S = (*I)->getTerminatorCondition(); 1573 1574 if (S && M->find(S) == M->end()) { 1575 unsigned x = M->size(); 1576 (*M)[S] = x; 1577 } 1578 } 1579 1580 return M; 1581} 1582 1583CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 1584 assert(S != NULL); 1585 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 1586 1587 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 1588 BlkExprMapTy::iterator I = M->find(S); 1589 1590 if (I == M->end()) return CFG::BlkExprNumTy(); 1591 else return CFG::BlkExprNumTy(I->second); 1592} 1593 1594unsigned CFG::getNumBlkExprs() { 1595 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 1596 return M->size(); 1597 else { 1598 // We assume callers interested in the number of BlkExprs will want 1599 // the map constructed if it doesn't already exist. 1600 BlkExprMap = (void*) PopulateBlkExprMap(*this); 1601 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 1602 } 1603} 1604 1605//===----------------------------------------------------------------------===// 1606// Cleanup: CFG dstor. 1607//===----------------------------------------------------------------------===// 1608 1609CFG::~CFG() { 1610 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 1611} 1612 1613//===----------------------------------------------------------------------===// 1614// CFG pretty printing 1615//===----------------------------------------------------------------------===// 1616 1617namespace { 1618 1619class StmtPrinterHelper : public PrinterHelper { 1620 1621 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 1622 StmtMapTy StmtMap; 1623 signed CurrentBlock; 1624 unsigned CurrentStmt; 1625 const LangOptions &LangOpts; 1626public: 1627 1628 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 1629 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 1630 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 1631 unsigned j = 1; 1632 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 1633 BI != BEnd; ++BI, ++j ) 1634 StmtMap[*BI] = std::make_pair((*I)->getBlockID(),j); 1635 } 1636 } 1637 1638 virtual ~StmtPrinterHelper() {} 1639 1640 const LangOptions &getLangOpts() const { return LangOpts; } 1641 void setBlockID(signed i) { CurrentBlock = i; } 1642 void setStmtID(unsigned i) { CurrentStmt = i; } 1643 1644 virtual bool handledStmt(Stmt* Terminator, llvm::raw_ostream& OS) { 1645 1646 StmtMapTy::iterator I = StmtMap.find(Terminator); 1647 1648 if (I == StmtMap.end()) 1649 return false; 1650 1651 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 1652 && I->second.second == CurrentStmt) 1653 return false; 1654 1655 OS << "[B" << I->second.first << "." << I->second.second << "]"; 1656 return true; 1657 } 1658}; 1659} // end anonymous namespace 1660 1661 1662namespace { 1663class CFGBlockTerminatorPrint 1664 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 1665 1666 llvm::raw_ostream& OS; 1667 StmtPrinterHelper* Helper; 1668 PrintingPolicy Policy; 1669 1670public: 1671 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 1672 const PrintingPolicy &Policy) 1673 : OS(os), Helper(helper), Policy(Policy) {} 1674 1675 void VisitIfStmt(IfStmt* I) { 1676 OS << "if "; 1677 I->getCond()->printPretty(OS,Helper,Policy); 1678 } 1679 1680 // Default case. 1681 void VisitStmt(Stmt* Terminator) { 1682 Terminator->printPretty(OS, Helper, Policy); 1683 } 1684 1685 void VisitForStmt(ForStmt* F) { 1686 OS << "for (" ; 1687 if (F->getInit()) OS << "..."; 1688 OS << "; "; 1689 if (Stmt* C = F->getCond()) C->printPretty(OS, Helper, Policy); 1690 OS << "; "; 1691 if (F->getInc()) OS << "..."; 1692 OS << ")"; 1693 } 1694 1695 void VisitWhileStmt(WhileStmt* W) { 1696 OS << "while " ; 1697 if (Stmt* C = W->getCond()) C->printPretty(OS, Helper, Policy); 1698 } 1699 1700 void VisitDoStmt(DoStmt* D) { 1701 OS << "do ... while "; 1702 if (Stmt* C = D->getCond()) C->printPretty(OS, Helper, Policy); 1703 } 1704 1705 void VisitSwitchStmt(SwitchStmt* Terminator) { 1706 OS << "switch "; 1707 Terminator->getCond()->printPretty(OS, Helper, Policy); 1708 } 1709 1710 void VisitConditionalOperator(ConditionalOperator* C) { 1711 C->getCond()->printPretty(OS, Helper, Policy); 1712 OS << " ? ... : ..."; 1713 } 1714 1715 void VisitChooseExpr(ChooseExpr* C) { 1716 OS << "__builtin_choose_expr( "; 1717 C->getCond()->printPretty(OS, Helper, Policy); 1718 OS << " )"; 1719 } 1720 1721 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1722 OS << "goto *"; 1723 I->getTarget()->printPretty(OS, Helper, Policy); 1724 } 1725 1726 void VisitBinaryOperator(BinaryOperator* B) { 1727 if (!B->isLogicalOp()) { 1728 VisitExpr(B); 1729 return; 1730 } 1731 1732 B->getLHS()->printPretty(OS, Helper, Policy); 1733 1734 switch (B->getOpcode()) { 1735 case BinaryOperator::LOr: 1736 OS << " || ..."; 1737 return; 1738 case BinaryOperator::LAnd: 1739 OS << " && ..."; 1740 return; 1741 default: 1742 assert(false && "Invalid logical operator."); 1743 } 1744 } 1745 1746 void VisitExpr(Expr* E) { 1747 E->printPretty(OS, Helper, Policy); 1748 } 1749}; 1750} // end anonymous namespace 1751 1752 1753static void print_stmt(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 1754 Stmt* Terminator) { 1755 if (Helper) { 1756 // special printing for statement-expressions. 1757 if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) { 1758 CompoundStmt* Sub = SE->getSubStmt(); 1759 1760 if (Sub->child_begin() != Sub->child_end()) { 1761 OS << "({ ... ; "; 1762 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 1763 OS << " })\n"; 1764 return; 1765 } 1766 } 1767 1768 // special printing for comma expressions. 1769 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) { 1770 if (B->getOpcode() == BinaryOperator::Comma) { 1771 OS << "... , "; 1772 Helper->handledStmt(B->getRHS(),OS); 1773 OS << '\n'; 1774 return; 1775 } 1776 } 1777 } 1778 1779 Terminator->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 1780 1781 // Expressions need a newline. 1782 if (isa<Expr>(Terminator)) OS << '\n'; 1783} 1784 1785static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 1786 const CFGBlock& B, 1787 StmtPrinterHelper* Helper, bool print_edges) { 1788 1789 if (Helper) Helper->setBlockID(B.getBlockID()); 1790 1791 // Print the header. 1792 OS << "\n [ B" << B.getBlockID(); 1793 1794 if (&B == &cfg->getEntry()) 1795 OS << " (ENTRY) ]\n"; 1796 else if (&B == &cfg->getExit()) 1797 OS << " (EXIT) ]\n"; 1798 else if (&B == cfg->getIndirectGotoBlock()) 1799 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 1800 else 1801 OS << " ]\n"; 1802 1803 // Print the label of this block. 1804 if (Stmt* Terminator = const_cast<Stmt*>(B.getLabel())) { 1805 1806 if (print_edges) 1807 OS << " "; 1808 1809 if (LabelStmt* L = dyn_cast<LabelStmt>(Terminator)) 1810 OS << L->getName(); 1811 else if (CaseStmt* C = dyn_cast<CaseStmt>(Terminator)) { 1812 OS << "case "; 1813 C->getLHS()->printPretty(OS, Helper, 1814 PrintingPolicy(Helper->getLangOpts())); 1815 if (C->getRHS()) { 1816 OS << " ... "; 1817 C->getRHS()->printPretty(OS, Helper, 1818 PrintingPolicy(Helper->getLangOpts())); 1819 } 1820 } else if (isa<DefaultStmt>(Terminator)) 1821 OS << "default"; 1822 else 1823 assert(false && "Invalid label statement in CFGBlock."); 1824 1825 OS << ":\n"; 1826 } 1827 1828 // Iterate through the statements in the block and print them. 1829 unsigned j = 1; 1830 1831 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 1832 I != E ; ++I, ++j ) { 1833 1834 // Print the statement # in the basic block and the statement itself. 1835 if (print_edges) 1836 OS << " "; 1837 1838 OS << llvm::format("%3d", j) << ": "; 1839 1840 if (Helper) 1841 Helper->setStmtID(j); 1842 1843 print_stmt(OS,Helper,*I); 1844 } 1845 1846 // Print the terminator of this block. 1847 if (B.getTerminator()) { 1848 if (print_edges) 1849 OS << " "; 1850 1851 OS << " T: "; 1852 1853 if (Helper) Helper->setBlockID(-1); 1854 1855 CFGBlockTerminatorPrint TPrinter(OS, Helper, 1856 PrintingPolicy(Helper->getLangOpts())); 1857 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 1858 OS << '\n'; 1859 } 1860 1861 if (print_edges) { 1862 // Print the predecessors of this block. 1863 OS << " Predecessors (" << B.pred_size() << "):"; 1864 unsigned i = 0; 1865 1866 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 1867 I != E; ++I, ++i) { 1868 1869 if (i == 8 || (i-8) == 0) 1870 OS << "\n "; 1871 1872 OS << " B" << (*I)->getBlockID(); 1873 } 1874 1875 OS << '\n'; 1876 1877 // Print the successors of this block. 1878 OS << " Successors (" << B.succ_size() << "):"; 1879 i = 0; 1880 1881 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 1882 I != E; ++I, ++i) { 1883 1884 if (i == 8 || (i-8) % 10 == 0) 1885 OS << "\n "; 1886 1887 if (*I) 1888 OS << " B" << (*I)->getBlockID(); 1889 else 1890 OS << " NULL"; 1891 } 1892 1893 OS << '\n'; 1894 } 1895} 1896 1897 1898/// dump - A simple pretty printer of a CFG that outputs to stderr. 1899void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 1900 1901/// print - A simple pretty printer of a CFG that outputs to an ostream. 1902void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 1903 StmtPrinterHelper Helper(this, LO); 1904 1905 // Print the entry block. 1906 print_block(OS, this, getEntry(), &Helper, true); 1907 1908 // Iterate through the CFGBlocks and print them one by one. 1909 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 1910 // Skip the entry block, because we already printed it. 1911 if (&(**I) == &getEntry() || &(**I) == &getExit()) 1912 continue; 1913 1914 print_block(OS, this, **I, &Helper, true); 1915 } 1916 1917 // Print the exit block. 1918 print_block(OS, this, getExit(), &Helper, true); 1919 OS.flush(); 1920} 1921 1922/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 1923void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 1924 print(llvm::errs(), cfg, LO); 1925} 1926 1927/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 1928/// Generally this will only be called from CFG::print. 1929void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 1930 const LangOptions &LO) const { 1931 StmtPrinterHelper Helper(cfg, LO); 1932 print_block(OS, cfg, *this, &Helper, true); 1933} 1934 1935/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 1936void CFGBlock::printTerminator(llvm::raw_ostream &OS, 1937 const LangOptions &LO) const { 1938 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 1939 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 1940} 1941 1942Stmt* CFGBlock::getTerminatorCondition() { 1943 1944 if (!Terminator) 1945 return NULL; 1946 1947 Expr* E = NULL; 1948 1949 switch (Terminator->getStmtClass()) { 1950 default: 1951 break; 1952 1953 case Stmt::ForStmtClass: 1954 E = cast<ForStmt>(Terminator)->getCond(); 1955 break; 1956 1957 case Stmt::WhileStmtClass: 1958 E = cast<WhileStmt>(Terminator)->getCond(); 1959 break; 1960 1961 case Stmt::DoStmtClass: 1962 E = cast<DoStmt>(Terminator)->getCond(); 1963 break; 1964 1965 case Stmt::IfStmtClass: 1966 E = cast<IfStmt>(Terminator)->getCond(); 1967 break; 1968 1969 case Stmt::ChooseExprClass: 1970 E = cast<ChooseExpr>(Terminator)->getCond(); 1971 break; 1972 1973 case Stmt::IndirectGotoStmtClass: 1974 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 1975 break; 1976 1977 case Stmt::SwitchStmtClass: 1978 E = cast<SwitchStmt>(Terminator)->getCond(); 1979 break; 1980 1981 case Stmt::ConditionalOperatorClass: 1982 E = cast<ConditionalOperator>(Terminator)->getCond(); 1983 break; 1984 1985 case Stmt::BinaryOperatorClass: // '&&' and '||' 1986 E = cast<BinaryOperator>(Terminator)->getLHS(); 1987 break; 1988 1989 case Stmt::ObjCForCollectionStmtClass: 1990 return Terminator; 1991 } 1992 1993 return E ? E->IgnoreParens() : NULL; 1994} 1995 1996bool CFGBlock::hasBinaryBranchTerminator() const { 1997 1998 if (!Terminator) 1999 return false; 2000 2001 Expr* E = NULL; 2002 2003 switch (Terminator->getStmtClass()) { 2004 default: 2005 return false; 2006 2007 case Stmt::ForStmtClass: 2008 case Stmt::WhileStmtClass: 2009 case Stmt::DoStmtClass: 2010 case Stmt::IfStmtClass: 2011 case Stmt::ChooseExprClass: 2012 case Stmt::ConditionalOperatorClass: 2013 case Stmt::BinaryOperatorClass: 2014 return true; 2015 } 2016 2017 return E ? E->IgnoreParens() : NULL; 2018} 2019 2020 2021//===----------------------------------------------------------------------===// 2022// CFG Graphviz Visualization 2023//===----------------------------------------------------------------------===// 2024 2025 2026#ifndef NDEBUG 2027static StmtPrinterHelper* GraphHelper; 2028#endif 2029 2030void CFG::viewCFG(const LangOptions &LO) const { 2031#ifndef NDEBUG 2032 StmtPrinterHelper H(this, LO); 2033 GraphHelper = &H; 2034 llvm::ViewGraph(this,"CFG"); 2035 GraphHelper = NULL; 2036#endif 2037} 2038 2039namespace llvm { 2040template<> 2041struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2042 2043 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2044 2045 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 2046 2047#ifndef NDEBUG 2048 std::string OutSStr; 2049 llvm::raw_string_ostream Out(OutSStr); 2050 print_block(Out,Graph, *Node, GraphHelper, false); 2051 std::string& OutStr = Out.str(); 2052 2053 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2054 2055 // Process string output to make it nicer... 2056 for (unsigned i = 0; i != OutStr.length(); ++i) 2057 if (OutStr[i] == '\n') { // Left justify 2058 OutStr[i] = '\\'; 2059 OutStr.insert(OutStr.begin()+i+1, 'l'); 2060 } 2061 2062 return OutStr; 2063#else 2064 return ""; 2065#endif 2066 } 2067}; 2068} // end namespace llvm 2069