CFG.cpp revision 16e658669752f90dd0a3d60373df9dea48456892
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 *VisitBlockDeclRefExpr(BlockDeclRefExpr* E, bool alwaysAdd); 91 CFGBlock *VisitBreakStmt(BreakStmt *B); 92 CFGBlock *VisitCallExpr(CallExpr *C, bool alwaysAdd); 93 CFGBlock *VisitCaseStmt(CaseStmt *C); 94 CFGBlock *VisitChooseExpr(ChooseExpr *C); 95 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 96 CFGBlock *VisitConditionalOperator(ConditionalOperator *C); 97 CFGBlock *VisitContinueStmt(ContinueStmt *C); 98 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 99 CFGBlock *VisitDeclStmt(DeclStmt *DS); 100 CFGBlock *VisitDeclSubExpr(Decl* D); 101 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 102 CFGBlock *VisitDoStmt(DoStmt *D); 103 CFGBlock *VisitForStmt(ForStmt *F); 104 CFGBlock *VisitGotoStmt(GotoStmt* G); 105 CFGBlock *VisitIfStmt(IfStmt *I); 106 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 107 CFGBlock *VisitLabelStmt(LabelStmt *L); 108 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 109 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 110 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 111 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 112 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 113 CFGBlock *VisitReturnStmt(ReturnStmt* R); 114 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, bool alwaysAdd); 115 CFGBlock *VisitStmtExpr(StmtExpr *S, bool alwaysAdd); 116 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 117 CFGBlock *VisitWhileStmt(WhileStmt *W); 118 119 CFGBlock *Visit(Stmt *S, bool alwaysAdd = false); 120 CFGBlock *VisitStmt(Stmt *S, bool alwaysAdd); 121 CFGBlock *VisitChildren(Stmt* S); 122 123 // NYS == Not Yet Supported 124 CFGBlock* NYS() { 125 badCFG = true; 126 return Block; 127 } 128 129 void autoCreateBlock() { if (!Block) Block = createBlock(); } 130 CFGBlock *createBlock(bool add_successor = true); 131 bool FinishBlock(CFGBlock* B); 132 CFGBlock *addStmt(Stmt *S) { return Visit(S, true); } 133 134 void AppendStmt(CFGBlock *B, Stmt *S) { 135 B->appendStmt(S, cfg->getBumpVectorContext()); 136 } 137 138 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 139 B->addSuccessor(S, cfg->getBumpVectorContext()); 140 } 141 142 /// TryResult - a class representing a variant over the values 143 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 144 /// and is used by the CFGBuilder to decide if a branch condition 145 /// can be decided up front during CFG construction. 146 class TryResult { 147 int X; 148 public: 149 TryResult(bool b) : X(b ? 1 : 0) {} 150 TryResult() : X(-1) {} 151 152 bool isTrue() const { return X == 1; } 153 bool isFalse() const { return X == 0; } 154 bool isKnown() const { return X >= 0; } 155 void negate() { 156 assert(isKnown()); 157 X ^= 0x1; 158 } 159 }; 160 161 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 162 /// if we can evaluate to a known value, otherwise return -1. 163 TryResult TryEvaluateBool(Expr *S) { 164 Expr::EvalResult Result; 165 if (!S->isTypeDependent() && !S->isValueDependent() && 166 S->Evaluate(Result, *Context) && Result.Val.isInt()) 167 return Result.Val.getInt().getBoolValue(); 168 169 return TryResult(); 170 } 171 172 bool badCFG; 173}; 174 175// FIXME: Add support for dependent-sized array types in C++? 176// Does it even make sense to build a CFG for an uninstantiated template? 177static VariableArrayType* FindVA(Type* t) { 178 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 179 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 180 if (vat->getSizeExpr()) 181 return vat; 182 183 t = vt->getElementType().getTypePtr(); 184 } 185 186 return 0; 187} 188 189/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 190/// arbitrary statement. Examples include a single expression or a function 191/// body (compound statement). The ownership of the returned CFG is 192/// transferred to the caller. If CFG construction fails, this method returns 193/// NULL. 194CFG* CFGBuilder::buildCFG(Stmt* Statement, ASTContext* C) { 195 Context = C; 196 assert(cfg.get()); 197 if (!Statement) 198 return NULL; 199 200 badCFG = false; 201 202 // Create an empty block that will serve as the exit block for the CFG. Since 203 // this is the first block added to the CFG, it will be implicitly registered 204 // as the exit block. 205 Succ = createBlock(); 206 assert(Succ == &cfg->getExit()); 207 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 208 209 // Visit the statements and create the CFG. 210 CFGBlock* B = addStmt(Statement); 211 if (!B) 212 B = Succ; 213 214 if (B) { 215 // Finalize the last constructed block. This usually involves reversing the 216 // order of the statements in the block. 217 if (Block) FinishBlock(B); 218 219 // Backpatch the gotos whose label -> block mappings we didn't know when we 220 // encountered them. 221 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 222 E = BackpatchBlocks.end(); I != E; ++I ) { 223 224 CFGBlock* B = *I; 225 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 226 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 227 228 // If there is no target for the goto, then we are looking at an 229 // incomplete AST. Handle this by not registering a successor. 230 if (LI == LabelMap.end()) continue; 231 232 AddSuccessor(B, LI->second); 233 } 234 235 // Add successors to the Indirect Goto Dispatch block (if we have one). 236 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 237 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 238 E = AddressTakenLabels.end(); I != E; ++I ) { 239 240 // Lookup the target block. 241 LabelMapTy::iterator LI = LabelMap.find(*I); 242 243 // If there is no target block that contains label, then we are looking 244 // at an incomplete AST. Handle this by not registering a successor. 245 if (LI == LabelMap.end()) continue; 246 247 AddSuccessor(B, LI->second); 248 } 249 250 Succ = B; 251 } 252 253 // Create an empty entry block that has no predecessors. 254 cfg->setEntry(createBlock()); 255 256 return badCFG ? NULL : cfg.take(); 257} 258 259/// createBlock - Used to lazily create blocks that are connected 260/// to the current (global) succcessor. 261CFGBlock* CFGBuilder::createBlock(bool add_successor) { 262 CFGBlock* B = cfg->createBlock(); 263 if (add_successor && Succ) 264 AddSuccessor(B, Succ); 265 return B; 266} 267 268/// FinishBlock - "Finalize" the block by checking if we have a bad CFG. 269bool CFGBuilder::FinishBlock(CFGBlock* B) { 270 if (badCFG) 271 return false; 272 273 assert(B); 274 return true; 275} 276 277/// Visit - Walk the subtree of a statement and add extra 278/// blocks for ternary operators, &&, and ||. We also process "," and 279/// DeclStmts (which may contain nested control-flow). 280CFGBlock* CFGBuilder::Visit(Stmt * S, bool alwaysAdd) { 281tryAgain: 282 switch (S->getStmtClass()) { 283 default: 284 return VisitStmt(S, alwaysAdd); 285 286 case Stmt::AddrLabelExprClass: 287 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), alwaysAdd); 288 289 case Stmt::BinaryOperatorClass: 290 return VisitBinaryOperator(cast<BinaryOperator>(S), alwaysAdd); 291 292 case Stmt::BlockExprClass: 293 return VisitBlockExpr(cast<BlockExpr>(S), alwaysAdd); 294 295 case Stmt::BlockDeclRefExprClass: 296 return VisitBlockDeclRefExpr(cast<BlockDeclRefExpr>(S), alwaysAdd); 297 298 case Stmt::BreakStmtClass: 299 return VisitBreakStmt(cast<BreakStmt>(S)); 300 301 case Stmt::CallExprClass: 302 return VisitCallExpr(cast<CallExpr>(S), alwaysAdd); 303 304 case Stmt::CaseStmtClass: 305 return VisitCaseStmt(cast<CaseStmt>(S)); 306 307 case Stmt::ChooseExprClass: 308 return VisitChooseExpr(cast<ChooseExpr>(S)); 309 310 case Stmt::CompoundStmtClass: 311 return VisitCompoundStmt(cast<CompoundStmt>(S)); 312 313 case Stmt::ConditionalOperatorClass: 314 return VisitConditionalOperator(cast<ConditionalOperator>(S)); 315 316 case Stmt::ContinueStmtClass: 317 return VisitContinueStmt(cast<ContinueStmt>(S)); 318 319 case Stmt::DeclStmtClass: 320 return VisitDeclStmt(cast<DeclStmt>(S)); 321 322 case Stmt::DefaultStmtClass: 323 return VisitDefaultStmt(cast<DefaultStmt>(S)); 324 325 case Stmt::DoStmtClass: 326 return VisitDoStmt(cast<DoStmt>(S)); 327 328 case Stmt::ForStmtClass: 329 return VisitForStmt(cast<ForStmt>(S)); 330 331 case Stmt::GotoStmtClass: 332 return VisitGotoStmt(cast<GotoStmt>(S)); 333 334 case Stmt::IfStmtClass: 335 return VisitIfStmt(cast<IfStmt>(S)); 336 337 case Stmt::IndirectGotoStmtClass: 338 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 339 340 case Stmt::LabelStmtClass: 341 return VisitLabelStmt(cast<LabelStmt>(S)); 342 343 case Stmt::ObjCAtCatchStmtClass: 344 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 345 346 case Stmt::CXXThrowExprClass: 347 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 348 349 case Stmt::ObjCAtSynchronizedStmtClass: 350 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 351 352 case Stmt::ObjCAtThrowStmtClass: 353 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 354 355 case Stmt::ObjCAtTryStmtClass: 356 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 357 358 case Stmt::ObjCForCollectionStmtClass: 359 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 360 361 case Stmt::ParenExprClass: 362 S = cast<ParenExpr>(S)->getSubExpr(); 363 goto tryAgain; 364 365 case Stmt::NullStmtClass: 366 return Block; 367 368 case Stmt::ReturnStmtClass: 369 return VisitReturnStmt(cast<ReturnStmt>(S)); 370 371 case Stmt::SizeOfAlignOfExprClass: 372 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), alwaysAdd); 373 374 case Stmt::StmtExprClass: 375 return VisitStmtExpr(cast<StmtExpr>(S), alwaysAdd); 376 377 case Stmt::SwitchStmtClass: 378 return VisitSwitchStmt(cast<SwitchStmt>(S)); 379 380 case Stmt::WhileStmtClass: 381 return VisitWhileStmt(cast<WhileStmt>(S)); 382 } 383} 384 385CFGBlock *CFGBuilder::VisitStmt(Stmt *S, bool alwaysAdd) { 386 if (alwaysAdd) { 387 autoCreateBlock(); 388 AppendStmt(Block, S); 389 } 390 391 return VisitChildren(S); 392} 393 394/// VisitChildren - Visit the children of a Stmt. 395CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 396 CFGBlock *B = Block; 397 for (Stmt::child_iterator I = Terminator->child_begin(), 398 E = Terminator->child_end(); I != E; ++I) { 399 if (*I) B = Visit(*I); 400 } 401 return B; 402} 403 404CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, bool alwaysAdd) { 405 AddressTakenLabels.insert(A->getLabel()); 406 407 if (alwaysAdd) { 408 autoCreateBlock(); 409 AppendStmt(Block, A); 410 } 411 412 return Block; 413} 414 415CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, bool alwaysAdd) { 416 if (B->isLogicalOp()) { // && or || 417 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 418 AppendStmt(ConfluenceBlock, B); 419 420 if (!FinishBlock(ConfluenceBlock)) 421 return 0; 422 423 // create the block evaluating the LHS 424 CFGBlock* LHSBlock = createBlock(false); 425 LHSBlock->setTerminator(B); 426 427 // create the block evaluating the RHS 428 Succ = ConfluenceBlock; 429 Block = NULL; 430 CFGBlock* RHSBlock = addStmt(B->getRHS()); 431 if (!FinishBlock(RHSBlock)) 432 return 0; 433 434 // See if this is a known constant. 435 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 436 if (KnownVal.isKnown() && (B->getOpcode() == BinaryOperator::LOr)) 437 KnownVal.negate(); 438 439 // Now link the LHSBlock with RHSBlock. 440 if (B->getOpcode() == BinaryOperator::LOr) { 441 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 442 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 443 } else { 444 assert (B->getOpcode() == BinaryOperator::LAnd); 445 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 446 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 447 } 448 449 // Generate the blocks for evaluating the LHS. 450 Block = LHSBlock; 451 return addStmt(B->getLHS()); 452 } 453 else if (B->getOpcode() == BinaryOperator::Comma) { // , 454 autoCreateBlock(); 455 AppendStmt(Block, B); 456 addStmt(B->getRHS()); 457 return addStmt(B->getLHS()); 458 } 459 460 return VisitStmt(B, alwaysAdd); 461} 462 463CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, bool alwaysAdd) { 464 if (alwaysAdd) { 465 autoCreateBlock(); 466 AppendStmt(Block, E); 467 } 468 return Block; 469} 470 471CFGBlock *CFGBuilder::VisitBlockDeclRefExpr(BlockDeclRefExpr* E, 472 bool alwaysAdd) { 473 // FIXME 474 return NYS(); 475} 476 477CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 478 // "break" is a control-flow statement. Thus we stop processing the current 479 // block. 480 if (Block && !FinishBlock(Block)) 481 return 0; 482 483 // Now create a new block that ends with the break statement. 484 Block = createBlock(false); 485 Block->setTerminator(B); 486 487 // If there is no target for the break, then we are looking at an incomplete 488 // AST. This means that the CFG cannot be constructed. 489 if (BreakTargetBlock) 490 AddSuccessor(Block, BreakTargetBlock); 491 else 492 badCFG = true; 493 494 495 return Block; 496} 497 498CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, bool alwaysAdd) { 499 // If this is a call to a no-return function, this stops the block here. 500 bool NoReturn = false; 501 if (C->getCallee()->getType().getNoReturnAttr()) { 502 NoReturn = true; 503 } 504 505 if (FunctionDecl *FD = C->getDirectCallee()) 506 if (FD->hasAttr<NoReturnAttr>()) 507 NoReturn = true; 508 509 if (!NoReturn) 510 return VisitStmt(C, alwaysAdd); 511 512 if (Block && !FinishBlock(Block)) 513 return 0; 514 515 // Create new block with no successor for the remaining pieces. 516 Block = createBlock(false); 517 AppendStmt(Block, C); 518 519 // Wire this to the exit block directly. 520 AddSuccessor(Block, &cfg->getExit()); 521 522 return VisitChildren(C); 523} 524 525CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C) { 526 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 527 AppendStmt(ConfluenceBlock, C); 528 if (!FinishBlock(ConfluenceBlock)) 529 return 0; 530 531 Succ = ConfluenceBlock; 532 Block = NULL; 533 CFGBlock* LHSBlock = addStmt(C->getLHS()); 534 if (!FinishBlock(LHSBlock)) 535 return 0; 536 537 Succ = ConfluenceBlock; 538 Block = NULL; 539 CFGBlock* RHSBlock = addStmt(C->getRHS()); 540 if (!FinishBlock(RHSBlock)) 541 return 0; 542 543 Block = createBlock(false); 544 // See if this is a known constant. 545 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 546 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 547 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 548 Block->setTerminator(C); 549 return addStmt(C->getCond()); 550} 551 552 553CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 554 CFGBlock* LastBlock = Block; 555 556 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 557 I != E; ++I ) { 558 LastBlock = addStmt(*I); 559 560 if (badCFG) 561 return NULL; 562 } 563 return LastBlock; 564} 565 566CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C) { 567 // Create the confluence block that will "merge" the results of the ternary 568 // expression. 569 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 570 AppendStmt(ConfluenceBlock, C); 571 if (!FinishBlock(ConfluenceBlock)) 572 return 0; 573 574 // Create a block for the LHS expression if there is an LHS expression. A 575 // GCC extension allows LHS to be NULL, causing the condition to be the 576 // value that is returned instead. 577 // e.g: x ?: y is shorthand for: x ? x : y; 578 Succ = ConfluenceBlock; 579 Block = NULL; 580 CFGBlock* LHSBlock = NULL; 581 if (C->getLHS()) { 582 LHSBlock = addStmt(C->getLHS()); 583 if (!FinishBlock(LHSBlock)) 584 return 0; 585 Block = NULL; 586 } 587 588 // Create the block for the RHS expression. 589 Succ = ConfluenceBlock; 590 CFGBlock* RHSBlock = addStmt(C->getRHS()); 591 if (!FinishBlock(RHSBlock)) 592 return 0; 593 594 // Create the block that will contain the condition. 595 Block = createBlock(false); 596 597 // See if this is a known constant. 598 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 599 if (LHSBlock) { 600 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 601 } else { 602 if (KnownVal.isFalse()) { 603 // If we know the condition is false, add NULL as the successor for 604 // the block containing the condition. In this case, the confluence 605 // block will have just one predecessor. 606 AddSuccessor(Block, 0); 607 assert(ConfluenceBlock->pred_size() == 1); 608 } else { 609 // If we have no LHS expression, add the ConfluenceBlock as a direct 610 // successor for the block containing the condition. Moreover, we need to 611 // reverse the order of the predecessors in the ConfluenceBlock because 612 // the RHSBlock will have been added to the succcessors already, and we 613 // want the first predecessor to the the block containing the expression 614 // for the case when the ternary expression evaluates to true. 615 AddSuccessor(Block, ConfluenceBlock); 616 assert(ConfluenceBlock->pred_size() == 2); 617 std::reverse(ConfluenceBlock->pred_begin(), 618 ConfluenceBlock->pred_end()); 619 } 620 } 621 622 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 623 Block->setTerminator(C); 624 return addStmt(C->getCond()); 625} 626 627CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 628 autoCreateBlock(); 629 630 if (DS->isSingleDecl()) { 631 AppendStmt(Block, DS); 632 return VisitDeclSubExpr(DS->getSingleDecl()); 633 } 634 635 CFGBlock *B = 0; 636 637 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 638 typedef llvm::SmallVector<Decl*,10> BufTy; 639 BufTy Buf(DS->decl_begin(), DS->decl_end()); 640 641 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 642 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 643 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 644 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 645 646 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 647 // automatically freed with the CFG. 648 DeclGroupRef DG(*I); 649 Decl *D = *I; 650 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 651 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 652 653 // Append the fake DeclStmt to block. 654 AppendStmt(Block, DSNew); 655 B = VisitDeclSubExpr(D); 656 } 657 658 return B; 659} 660 661/// VisitDeclSubExpr - Utility method to add block-level expressions for 662/// initializers in Decls. 663CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 664 assert(Block); 665 666 VarDecl *VD = dyn_cast<VarDecl>(D); 667 668 if (!VD) 669 return Block; 670 671 Expr *Init = VD->getInit(); 672 673 if (Init) { 674 // Optimization: Don't create separate block-level statements for literals. 675 switch (Init->getStmtClass()) { 676 case Stmt::IntegerLiteralClass: 677 case Stmt::CharacterLiteralClass: 678 case Stmt::StringLiteralClass: 679 break; 680 default: 681 Block = addStmt(Init); 682 } 683 } 684 685 // If the type of VD is a VLA, then we must process its size expressions. 686 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 687 VA = FindVA(VA->getElementType().getTypePtr())) 688 Block = addStmt(VA->getSizeExpr()); 689 690 return Block; 691} 692 693CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 694 // We may see an if statement in the middle of a basic block, or it may be the 695 // first statement we are processing. In either case, we create a new basic 696 // block. First, we create the blocks for the then...else statements, and 697 // then we create the block containing the if statement. If we were in the 698 // middle of a block, we stop processing that block. That block is then the 699 // implicit successor for the "then" and "else" clauses. 700 701 // The block we were proccessing is now finished. Make it the successor 702 // block. 703 if (Block) { 704 Succ = Block; 705 if (!FinishBlock(Block)) 706 return 0; 707 } 708 709 // Process the false branch. 710 CFGBlock* ElseBlock = Succ; 711 712 if (Stmt* Else = I->getElse()) { 713 SaveAndRestore<CFGBlock*> sv(Succ); 714 715 // NULL out Block so that the recursive call to Visit will 716 // create a new basic block. 717 Block = NULL; 718 ElseBlock = addStmt(Else); 719 720 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 721 ElseBlock = sv.get(); 722 else if (Block) { 723 if (!FinishBlock(ElseBlock)) 724 return 0; 725 } 726 } 727 728 // Process the true branch. 729 CFGBlock* ThenBlock; 730 { 731 Stmt* Then = I->getThen(); 732 assert (Then); 733 SaveAndRestore<CFGBlock*> sv(Succ); 734 Block = NULL; 735 ThenBlock = addStmt(Then); 736 737 if (!ThenBlock) { 738 // We can reach here if the "then" body has all NullStmts. 739 // Create an empty block so we can distinguish between true and false 740 // branches in path-sensitive analyses. 741 ThenBlock = createBlock(false); 742 AddSuccessor(ThenBlock, sv.get()); 743 } else if (Block) { 744 if (!FinishBlock(ThenBlock)) 745 return 0; 746 } 747 } 748 749 // Now create a new block containing the if statement. 750 Block = createBlock(false); 751 752 // Set the terminator of the new block to the If statement. 753 Block->setTerminator(I); 754 755 // See if this is a known constant. 756 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 757 758 // Now add the successors. 759 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 760 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 761 762 // Add the condition as the last statement in the new block. This may create 763 // new blocks as the condition may contain control-flow. Any newly created 764 // blocks will be pointed to be "Block". 765 return addStmt(I->getCond()); 766} 767 768 769CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 770 // If we were in the middle of a block we stop processing that block. 771 // 772 // NOTE: If a "return" appears in the middle of a block, this means that the 773 // code afterwards is DEAD (unreachable). We still keep a basic block 774 // for that code; a simple "mark-and-sweep" from the entry block will be 775 // able to report such dead blocks. 776 if (Block) 777 FinishBlock(Block); 778 779 // Create the new block. 780 Block = createBlock(false); 781 782 // The Exit block is the only successor. 783 AddSuccessor(Block, &cfg->getExit()); 784 785 // Add the return statement to the block. This may create new blocks if R 786 // contains control-flow (short-circuit operations). 787 return VisitStmt(R, true); 788} 789 790CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 791 // Get the block of the labeled statement. Add it to our map. 792 addStmt(L->getSubStmt()); 793 CFGBlock* LabelBlock = Block; 794 795 if (!LabelBlock) // This can happen when the body is empty, i.e. 796 LabelBlock = createBlock(); // scopes that only contains NullStmts. 797 798 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 799 LabelMap[ L ] = LabelBlock; 800 801 // Labels partition blocks, so this is the end of the basic block we were 802 // processing (L is the block's label). Because this is label (and we have 803 // already processed the substatement) there is no extra control-flow to worry 804 // about. 805 LabelBlock->setLabel(L); 806 if (!FinishBlock(LabelBlock)) 807 return 0; 808 809 // We set Block to NULL to allow lazy creation of a new block (if necessary); 810 Block = NULL; 811 812 // This block is now the implicit successor of other blocks. 813 Succ = LabelBlock; 814 815 return LabelBlock; 816} 817 818CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 819 // Goto is a control-flow statement. Thus we stop processing the current 820 // block and create a new one. 821 if (Block) 822 FinishBlock(Block); 823 824 Block = createBlock(false); 825 Block->setTerminator(G); 826 827 // If we already know the mapping to the label block add the successor now. 828 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 829 830 if (I == LabelMap.end()) 831 // We will need to backpatch this block later. 832 BackpatchBlocks.push_back(Block); 833 else 834 AddSuccessor(Block, I->second); 835 836 return Block; 837} 838 839CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 840 CFGBlock* LoopSuccessor = NULL; 841 842 // "for" is a control-flow statement. Thus we stop processing the current 843 // block. 844 if (Block) { 845 if (!FinishBlock(Block)) 846 return 0; 847 LoopSuccessor = Block; 848 } else 849 LoopSuccessor = Succ; 850 851 // Because of short-circuit evaluation, the condition of the loop can span 852 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 853 // evaluate the condition. 854 CFGBlock* ExitConditionBlock = createBlock(false); 855 CFGBlock* EntryConditionBlock = ExitConditionBlock; 856 857 // Set the terminator for the "exit" condition block. 858 ExitConditionBlock->setTerminator(F); 859 860 // Now add the actual condition to the condition block. Because the condition 861 // itself may contain control-flow, new blocks may be created. 862 if (Stmt* C = F->getCond()) { 863 Block = ExitConditionBlock; 864 EntryConditionBlock = addStmt(C); 865 if (Block) { 866 if (!FinishBlock(EntryConditionBlock)) 867 return 0; 868 } 869 } 870 871 // The condition block is the implicit successor for the loop body as well as 872 // any code above the loop. 873 Succ = EntryConditionBlock; 874 875 // See if this is a known constant. 876 TryResult KnownVal(true); 877 878 if (F->getCond()) 879 KnownVal = TryEvaluateBool(F->getCond()); 880 881 // Now create the loop body. 882 { 883 assert (F->getBody()); 884 885 // Save the current values for Block, Succ, and continue and break targets 886 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 887 save_continue(ContinueTargetBlock), 888 save_break(BreakTargetBlock); 889 890 // Create a new block to contain the (bottom) of the loop body. 891 Block = NULL; 892 893 if (Stmt* I = F->getInc()) { 894 // Generate increment code in its own basic block. This is the target of 895 // continue statements. 896 Succ = addStmt(I); 897 } else { 898 // No increment code. Create a special, empty, block that is used as the 899 // target block for "looping back" to the start of the loop. 900 assert(Succ == EntryConditionBlock); 901 Succ = createBlock(); 902 } 903 904 // Finish up the increment (or empty) block if it hasn't been already. 905 if (Block) { 906 assert(Block == Succ); 907 if (!FinishBlock(Block)) 908 return 0; 909 Block = 0; 910 } 911 912 ContinueTargetBlock = Succ; 913 914 // The starting block for the loop increment is the block that should 915 // represent the 'loop target' for looping back to the start of the loop. 916 ContinueTargetBlock->setLoopTarget(F); 917 918 // All breaks should go to the code following the loop. 919 BreakTargetBlock = LoopSuccessor; 920 921 // Now populate the body block, and in the process create new blocks as we 922 // walk the body of the loop. 923 CFGBlock* BodyBlock = addStmt(F->getBody()); 924 925 if (!BodyBlock) 926 BodyBlock = ContinueTargetBlock; // can happen for "for (...;...;...) ;" 927 else if (Block && !FinishBlock(BodyBlock)) 928 return 0; 929 930 // This new body block is a successor to our "exit" condition block. 931 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 932 } 933 934 // Link up the condition block with the code that follows the loop. (the 935 // false branch). 936 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 937 938 // If the loop contains initialization, create a new block for those 939 // statements. This block can also contain statements that precede the loop. 940 if (Stmt* I = F->getInit()) { 941 Block = createBlock(); 942 return addStmt(I); 943 } else { 944 // There is no loop initialization. We are thus basically a while loop. 945 // NULL out Block to force lazy block construction. 946 Block = NULL; 947 Succ = EntryConditionBlock; 948 return EntryConditionBlock; 949 } 950} 951 952CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 953 // Objective-C fast enumeration 'for' statements: 954 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 955 // 956 // for ( Type newVariable in collection_expression ) { statements } 957 // 958 // becomes: 959 // 960 // prologue: 961 // 1. collection_expression 962 // T. jump to loop_entry 963 // loop_entry: 964 // 1. side-effects of element expression 965 // 1. ObjCForCollectionStmt [performs binding to newVariable] 966 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 967 // TB: 968 // statements 969 // T. jump to loop_entry 970 // FB: 971 // what comes after 972 // 973 // and 974 // 975 // Type existingItem; 976 // for ( existingItem in expression ) { statements } 977 // 978 // becomes: 979 // 980 // the same with newVariable replaced with existingItem; the binding works 981 // the same except that for one ObjCForCollectionStmt::getElement() returns 982 // a DeclStmt and the other returns a DeclRefExpr. 983 // 984 985 CFGBlock* LoopSuccessor = 0; 986 987 if (Block) { 988 if (!FinishBlock(Block)) 989 return 0; 990 LoopSuccessor = Block; 991 Block = 0; 992 } else 993 LoopSuccessor = Succ; 994 995 // Build the condition blocks. 996 CFGBlock* ExitConditionBlock = createBlock(false); 997 CFGBlock* EntryConditionBlock = ExitConditionBlock; 998 999 // Set the terminator for the "exit" condition block. 1000 ExitConditionBlock->setTerminator(S); 1001 1002 // The last statement in the block should be the ObjCForCollectionStmt, which 1003 // performs the actual binding to 'element' and determines if there are any 1004 // more items in the collection. 1005 AppendStmt(ExitConditionBlock, S); 1006 Block = ExitConditionBlock; 1007 1008 // Walk the 'element' expression to see if there are any side-effects. We 1009 // generate new blocks as necesary. We DON'T add the statement by default to 1010 // the CFG unless it contains control-flow. 1011 EntryConditionBlock = Visit(S->getElement(), false); 1012 if (Block) { 1013 if (!FinishBlock(EntryConditionBlock)) 1014 return 0; 1015 Block = 0; 1016 } 1017 1018 // The condition block is the implicit successor for the loop body as well as 1019 // any code above the loop. 1020 Succ = EntryConditionBlock; 1021 1022 // Now create the true branch. 1023 { 1024 // Save the current values for Succ, continue and break targets. 1025 SaveAndRestore<CFGBlock*> save_Succ(Succ), 1026 save_continue(ContinueTargetBlock), save_break(BreakTargetBlock); 1027 1028 BreakTargetBlock = LoopSuccessor; 1029 ContinueTargetBlock = EntryConditionBlock; 1030 1031 CFGBlock* BodyBlock = addStmt(S->getBody()); 1032 1033 if (!BodyBlock) 1034 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1035 else if (Block) { 1036 if (!FinishBlock(BodyBlock)) 1037 return 0; 1038 } 1039 1040 // This new body block is a successor to our "exit" condition block. 1041 AddSuccessor(ExitConditionBlock, BodyBlock); 1042 } 1043 1044 // Link up the condition block with the code that follows the loop. 1045 // (the false branch). 1046 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1047 1048 // Now create a prologue block to contain the collection expression. 1049 Block = createBlock(); 1050 return addStmt(S->getCollection()); 1051} 1052 1053CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1054 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1055 1056 // Inline the body. 1057 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1058 1059 // The sync body starts its own basic block. This makes it a little easier 1060 // for diagnostic clients. 1061 if (SyncBlock) { 1062 if (!FinishBlock(SyncBlock)) 1063 return 0; 1064 1065 Block = 0; 1066 } 1067 1068 Succ = SyncBlock; 1069 1070 // Inline the sync expression. 1071 return addStmt(S->getSynchExpr()); 1072} 1073 1074CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1075 // FIXME 1076 return NYS(); 1077} 1078 1079CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1080 CFGBlock* LoopSuccessor = NULL; 1081 1082 // "while" is a control-flow statement. Thus we stop processing the current 1083 // block. 1084 if (Block) { 1085 if (!FinishBlock(Block)) 1086 return 0; 1087 LoopSuccessor = Block; 1088 } else 1089 LoopSuccessor = Succ; 1090 1091 // Because of short-circuit evaluation, the condition of the loop can span 1092 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1093 // evaluate the condition. 1094 CFGBlock* ExitConditionBlock = createBlock(false); 1095 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1096 1097 // Set the terminator for the "exit" condition block. 1098 ExitConditionBlock->setTerminator(W); 1099 1100 // Now add the actual condition to the condition block. Because the condition 1101 // itself may contain control-flow, new blocks may be created. Thus we update 1102 // "Succ" after adding the condition. 1103 if (Stmt* C = W->getCond()) { 1104 Block = ExitConditionBlock; 1105 EntryConditionBlock = addStmt(C); 1106 assert(Block == EntryConditionBlock); 1107 if (Block) { 1108 if (!FinishBlock(EntryConditionBlock)) 1109 return 0; 1110 } 1111 } 1112 1113 // The condition block is the implicit successor for the loop body as well as 1114 // any code above the loop. 1115 Succ = EntryConditionBlock; 1116 1117 // See if this is a known constant. 1118 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1119 1120 // Process the loop body. 1121 { 1122 assert(W->getBody()); 1123 1124 // Save the current values for Block, Succ, and continue and break targets 1125 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1126 save_continue(ContinueTargetBlock), 1127 save_break(BreakTargetBlock); 1128 1129 // Create an empty block to represent the transition block for looping back 1130 // to the head of the loop. 1131 Block = 0; 1132 assert(Succ == EntryConditionBlock); 1133 Succ = createBlock(); 1134 Succ->setLoopTarget(W); 1135 ContinueTargetBlock = Succ; 1136 1137 // All breaks should go to the code following the loop. 1138 BreakTargetBlock = LoopSuccessor; 1139 1140 // NULL out Block to force lazy instantiation of blocks for the body. 1141 Block = NULL; 1142 1143 // Create the body. The returned block is the entry to the loop body. 1144 CFGBlock* BodyBlock = addStmt(W->getBody()); 1145 1146 if (!BodyBlock) 1147 BodyBlock = ContinueTargetBlock; // can happen for "while(...) ;" 1148 else if (Block) { 1149 if (!FinishBlock(BodyBlock)) 1150 return 0; 1151 } 1152 1153 // Add the loop body entry as a successor to the condition. 1154 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1155 } 1156 1157 // Link up the condition block with the code that follows the loop. (the 1158 // false branch). 1159 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1160 1161 // There can be no more statements in the condition block since we loop back 1162 // to this block. NULL out Block to force lazy creation of another block. 1163 Block = NULL; 1164 1165 // Return the condition block, which is the dominating block for the loop. 1166 Succ = EntryConditionBlock; 1167 return EntryConditionBlock; 1168} 1169 1170 1171CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1172 // FIXME: For now we pretend that @catch and the code it contains does not 1173 // exit. 1174 return Block; 1175} 1176 1177CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1178 // FIXME: This isn't complete. We basically treat @throw like a return 1179 // statement. 1180 1181 // If we were in the middle of a block we stop processing that block. 1182 if (Block && !FinishBlock(Block)) 1183 return 0; 1184 1185 // Create the new block. 1186 Block = createBlock(false); 1187 1188 // The Exit block is the only successor. 1189 AddSuccessor(Block, &cfg->getExit()); 1190 1191 // Add the statement to the block. This may create new blocks if S contains 1192 // control-flow (short-circuit operations). 1193 return VisitStmt(S, true); 1194} 1195 1196CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1197 // If we were in the middle of a block we stop processing that block. 1198 if (Block && !FinishBlock(Block)) 1199 return 0; 1200 1201 // Create the new block. 1202 Block = createBlock(false); 1203 1204 // The Exit block is the only successor. 1205 AddSuccessor(Block, &cfg->getExit()); 1206 1207 // Add the statement to the block. This may create new blocks if S contains 1208 // control-flow (short-circuit operations). 1209 return VisitStmt(T, true); 1210} 1211 1212CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1213 CFGBlock* LoopSuccessor = NULL; 1214 1215 // "do...while" is a control-flow statement. Thus we stop processing the 1216 // current block. 1217 if (Block) { 1218 if (!FinishBlock(Block)) 1219 return 0; 1220 LoopSuccessor = Block; 1221 } else 1222 LoopSuccessor = Succ; 1223 1224 // Because of short-circuit evaluation, the condition of the loop can span 1225 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1226 // evaluate the condition. 1227 CFGBlock* ExitConditionBlock = createBlock(false); 1228 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1229 1230 // Set the terminator for the "exit" condition block. 1231 ExitConditionBlock->setTerminator(D); 1232 1233 // Now add the actual condition to the condition block. Because the condition 1234 // itself may contain control-flow, new blocks may be created. 1235 if (Stmt* C = D->getCond()) { 1236 Block = ExitConditionBlock; 1237 EntryConditionBlock = addStmt(C); 1238 if (Block) { 1239 if (!FinishBlock(EntryConditionBlock)) 1240 return 0; 1241 } 1242 } 1243 1244 // The condition block is the implicit successor for the loop body. 1245 Succ = EntryConditionBlock; 1246 1247 // See if this is a known constant. 1248 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1249 1250 // Process the loop body. 1251 CFGBlock* BodyBlock = NULL; 1252 { 1253 assert (D->getBody()); 1254 1255 // Save the current values for Block, Succ, and continue and break targets 1256 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1257 save_continue(ContinueTargetBlock), 1258 save_break(BreakTargetBlock); 1259 1260 // All continues within this loop should go to the condition block 1261 ContinueTargetBlock = EntryConditionBlock; 1262 1263 // All breaks should go to the code following the loop. 1264 BreakTargetBlock = LoopSuccessor; 1265 1266 // NULL out Block to force lazy instantiation of blocks for the body. 1267 Block = NULL; 1268 1269 // Create the body. The returned block is the entry to the loop body. 1270 BodyBlock = addStmt(D->getBody()); 1271 1272 if (!BodyBlock) 1273 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1274 else if (Block) { 1275 if (!FinishBlock(BodyBlock)) 1276 return 0; 1277 } 1278 1279 // Add an intermediate block between the BodyBlock and the 1280 // ExitConditionBlock to represent the "loop back" transition. Create an 1281 // empty block to represent the transition block for looping back to the 1282 // head of the loop. 1283 // FIXME: Can we do this more efficiently without adding another block? 1284 Block = NULL; 1285 Succ = BodyBlock; 1286 CFGBlock *LoopBackBlock = createBlock(); 1287 LoopBackBlock->setLoopTarget(D); 1288 1289 // Add the loop body entry as a successor to the condition. 1290 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : LoopBackBlock); 1291 } 1292 1293 // Link up the condition block with the code that follows the loop. 1294 // (the false branch). 1295 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1296 1297 // There can be no more statements in the body block(s) since we loop back to 1298 // the body. NULL out Block to force lazy creation of another block. 1299 Block = NULL; 1300 1301 // Return the loop body, which is the dominating block for the loop. 1302 Succ = BodyBlock; 1303 return BodyBlock; 1304} 1305 1306CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1307 // "continue" is a control-flow statement. Thus we stop processing the 1308 // current block. 1309 if (Block && !FinishBlock(Block)) 1310 return 0; 1311 1312 // Now create a new block that ends with the continue statement. 1313 Block = createBlock(false); 1314 Block->setTerminator(C); 1315 1316 // If there is no target for the continue, then we are looking at an 1317 // incomplete AST. This means the CFG cannot be constructed. 1318 if (ContinueTargetBlock) 1319 AddSuccessor(Block, ContinueTargetBlock); 1320 else 1321 badCFG = true; 1322 1323 return Block; 1324} 1325 1326CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1327 bool alwaysAdd) { 1328 1329 if (alwaysAdd) { 1330 autoCreateBlock(); 1331 AppendStmt(Block, E); 1332 } 1333 1334 // VLA types have expressions that must be evaluated. 1335 if (E->isArgumentType()) { 1336 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1337 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1338 addStmt(VA->getSizeExpr()); 1339 } 1340 1341 return Block; 1342} 1343 1344/// VisitStmtExpr - Utility method to handle (nested) statement 1345/// expressions (a GCC extension). 1346CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, bool alwaysAdd) { 1347 if (alwaysAdd) { 1348 autoCreateBlock(); 1349 AppendStmt(Block, SE); 1350 } 1351 return VisitCompoundStmt(SE->getSubStmt()); 1352} 1353 1354CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1355 // "switch" is a control-flow statement. Thus we stop processing the current 1356 // block. 1357 CFGBlock* SwitchSuccessor = NULL; 1358 1359 if (Block) { 1360 if (!FinishBlock(Block)) 1361 return 0; 1362 SwitchSuccessor = Block; 1363 } else SwitchSuccessor = Succ; 1364 1365 // Save the current "switch" context. 1366 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1367 save_break(BreakTargetBlock), 1368 save_default(DefaultCaseBlock); 1369 1370 // Set the "default" case to be the block after the switch statement. If the 1371 // switch statement contains a "default:", this value will be overwritten with 1372 // the block for that code. 1373 DefaultCaseBlock = SwitchSuccessor; 1374 1375 // Create a new block that will contain the switch statement. 1376 SwitchTerminatedBlock = createBlock(false); 1377 1378 // Now process the switch body. The code after the switch is the implicit 1379 // successor. 1380 Succ = SwitchSuccessor; 1381 BreakTargetBlock = SwitchSuccessor; 1382 1383 // When visiting the body, the case statements should automatically get linked 1384 // up to the switch. We also don't keep a pointer to the body, since all 1385 // control-flow from the switch goes to case/default statements. 1386 assert (Terminator->getBody() && "switch must contain a non-NULL body"); 1387 Block = NULL; 1388 CFGBlock *BodyBlock = addStmt(Terminator->getBody()); 1389 if (Block) { 1390 if (!FinishBlock(BodyBlock)) 1391 return 0; 1392 } 1393 1394 // If we have no "default:" case, the default transition is to the code 1395 // following the switch body. 1396 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1397 1398 // Add the terminator and condition in the switch block. 1399 SwitchTerminatedBlock->setTerminator(Terminator); 1400 assert (Terminator->getCond() && "switch condition must be non-NULL"); 1401 Block = SwitchTerminatedBlock; 1402 1403 return addStmt(Terminator->getCond()); 1404} 1405 1406CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1407 // CaseStmts are essentially labels, so they are the first statement in a 1408 // block. 1409 1410 if (CS->getSubStmt()) 1411 addStmt(CS->getSubStmt()); 1412 1413 CFGBlock* CaseBlock = Block; 1414 if (!CaseBlock) 1415 CaseBlock = createBlock(); 1416 1417 // Cases statements partition blocks, so this is the top of the basic block we 1418 // were processing (the "case XXX:" is the label). 1419 CaseBlock->setLabel(CS); 1420 1421 if (!FinishBlock(CaseBlock)) 1422 return 0; 1423 1424 // Add this block to the list of successors for the block with the switch 1425 // statement. 1426 assert(SwitchTerminatedBlock); 1427 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 1428 1429 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1430 Block = NULL; 1431 1432 // This block is now the implicit successor of other blocks. 1433 Succ = CaseBlock; 1434 1435 return CaseBlock; 1436} 1437 1438CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 1439 if (Terminator->getSubStmt()) 1440 addStmt(Terminator->getSubStmt()); 1441 1442 DefaultCaseBlock = Block; 1443 1444 if (!DefaultCaseBlock) 1445 DefaultCaseBlock = createBlock(); 1446 1447 // Default statements partition blocks, so this is the top of the basic block 1448 // we were processing (the "default:" is the label). 1449 DefaultCaseBlock->setLabel(Terminator); 1450 1451 if (!FinishBlock(DefaultCaseBlock)) 1452 return 0; 1453 1454 // Unlike case statements, we don't add the default block to the successors 1455 // for the switch statement immediately. This is done when we finish 1456 // processing the switch statement. This allows for the default case 1457 // (including a fall-through to the code after the switch statement) to always 1458 // be the last successor of a switch-terminated block. 1459 1460 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1461 Block = NULL; 1462 1463 // This block is now the implicit successor of other blocks. 1464 Succ = DefaultCaseBlock; 1465 1466 return DefaultCaseBlock; 1467} 1468 1469CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1470 // Lazily create the indirect-goto dispatch block if there isn't one already. 1471 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 1472 1473 if (!IBlock) { 1474 IBlock = createBlock(false); 1475 cfg->setIndirectGotoBlock(IBlock); 1476 } 1477 1478 // IndirectGoto is a control-flow statement. Thus we stop processing the 1479 // current block and create a new one. 1480 if (Block && !FinishBlock(Block)) 1481 return 0; 1482 1483 Block = createBlock(false); 1484 Block->setTerminator(I); 1485 AddSuccessor(Block, IBlock); 1486 return addStmt(I->getTarget()); 1487} 1488 1489} // end anonymous namespace 1490 1491/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 1492/// no successors or predecessors. If this is the first block created in the 1493/// CFG, it is automatically set to be the Entry and Exit of the CFG. 1494CFGBlock* CFG::createBlock() { 1495 bool first_block = begin() == end(); 1496 1497 // Create the block. 1498 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 1499 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 1500 Blocks.push_back(Mem, BlkBVC); 1501 1502 // If this is the first block, set it as the Entry and Exit. 1503 if (first_block) 1504 Entry = Exit = &back(); 1505 1506 // Return the block. 1507 return &back(); 1508} 1509 1510/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 1511/// CFG is returned to the caller. 1512CFG* CFG::buildCFG(Stmt* Statement, ASTContext *C) { 1513 CFGBuilder Builder; 1514 return Builder.buildCFG(Statement, C); 1515} 1516 1517//===----------------------------------------------------------------------===// 1518// CFG: Queries for BlkExprs. 1519//===----------------------------------------------------------------------===// 1520 1521namespace { 1522 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 1523} 1524 1525static void FindSubExprAssignments(Stmt* Terminator, llvm::SmallPtrSet<Expr*,50>& Set) { 1526 if (!Terminator) 1527 return; 1528 1529 for (Stmt::child_iterator I=Terminator->child_begin(), E=Terminator->child_end(); I!=E; ++I) { 1530 if (!*I) continue; 1531 1532 if (BinaryOperator* B = dyn_cast<BinaryOperator>(*I)) 1533 if (B->isAssignmentOp()) Set.insert(B); 1534 1535 FindSubExprAssignments(*I, Set); 1536 } 1537} 1538 1539static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 1540 BlkExprMapTy* M = new BlkExprMapTy(); 1541 1542 // Look for assignments that are used as subexpressions. These are the only 1543 // assignments that we want to *possibly* register as a block-level 1544 // expression. Basically, if an assignment occurs both in a subexpression and 1545 // at the block-level, it is a block-level expression. 1546 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 1547 1548 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 1549 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1550 FindSubExprAssignments(*BI, SubExprAssignments); 1551 1552 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 1553 1554 // Iterate over the statements again on identify the Expr* and Stmt* at the 1555 // block-level that are block-level expressions. 1556 1557 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1558 if (Expr* Exp = dyn_cast<Expr>(*BI)) { 1559 1560 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 1561 // Assignment expressions that are not nested within another 1562 // expression are really "statements" whose value is never used by 1563 // another expression. 1564 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 1565 continue; 1566 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 1567 // Special handling for statement expressions. The last statement in 1568 // the statement expression is also a block-level expr. 1569 const CompoundStmt* C = Terminator->getSubStmt(); 1570 if (!C->body_empty()) { 1571 unsigned x = M->size(); 1572 (*M)[C->body_back()] = x; 1573 } 1574 } 1575 1576 unsigned x = M->size(); 1577 (*M)[Exp] = x; 1578 } 1579 1580 // Look at terminators. The condition is a block-level expression. 1581 1582 Stmt* S = (*I)->getTerminatorCondition(); 1583 1584 if (S && M->find(S) == M->end()) { 1585 unsigned x = M->size(); 1586 (*M)[S] = x; 1587 } 1588 } 1589 1590 return M; 1591} 1592 1593CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 1594 assert(S != NULL); 1595 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 1596 1597 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 1598 BlkExprMapTy::iterator I = M->find(S); 1599 1600 if (I == M->end()) return CFG::BlkExprNumTy(); 1601 else return CFG::BlkExprNumTy(I->second); 1602} 1603 1604unsigned CFG::getNumBlkExprs() { 1605 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 1606 return M->size(); 1607 else { 1608 // We assume callers interested in the number of BlkExprs will want 1609 // the map constructed if it doesn't already exist. 1610 BlkExprMap = (void*) PopulateBlkExprMap(*this); 1611 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 1612 } 1613} 1614 1615//===----------------------------------------------------------------------===// 1616// Cleanup: CFG dstor. 1617//===----------------------------------------------------------------------===// 1618 1619CFG::~CFG() { 1620 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 1621} 1622 1623//===----------------------------------------------------------------------===// 1624// CFG pretty printing 1625//===----------------------------------------------------------------------===// 1626 1627namespace { 1628 1629class StmtPrinterHelper : public PrinterHelper { 1630 1631 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 1632 StmtMapTy StmtMap; 1633 signed CurrentBlock; 1634 unsigned CurrentStmt; 1635 const LangOptions &LangOpts; 1636public: 1637 1638 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 1639 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 1640 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 1641 unsigned j = 1; 1642 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 1643 BI != BEnd; ++BI, ++j ) 1644 StmtMap[*BI] = std::make_pair((*I)->getBlockID(),j); 1645 } 1646 } 1647 1648 virtual ~StmtPrinterHelper() {} 1649 1650 const LangOptions &getLangOpts() const { return LangOpts; } 1651 void setBlockID(signed i) { CurrentBlock = i; } 1652 void setStmtID(unsigned i) { CurrentStmt = i; } 1653 1654 virtual bool handledStmt(Stmt* Terminator, llvm::raw_ostream& OS) { 1655 1656 StmtMapTy::iterator I = StmtMap.find(Terminator); 1657 1658 if (I == StmtMap.end()) 1659 return false; 1660 1661 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 1662 && I->second.second == CurrentStmt) 1663 return false; 1664 1665 OS << "[B" << I->second.first << "." << I->second.second << "]"; 1666 return true; 1667 } 1668}; 1669} // end anonymous namespace 1670 1671 1672namespace { 1673class CFGBlockTerminatorPrint 1674 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 1675 1676 llvm::raw_ostream& OS; 1677 StmtPrinterHelper* Helper; 1678 PrintingPolicy Policy; 1679 1680public: 1681 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 1682 const PrintingPolicy &Policy) 1683 : OS(os), Helper(helper), Policy(Policy) {} 1684 1685 void VisitIfStmt(IfStmt* I) { 1686 OS << "if "; 1687 I->getCond()->printPretty(OS,Helper,Policy); 1688 } 1689 1690 // Default case. 1691 void VisitStmt(Stmt* Terminator) { 1692 Terminator->printPretty(OS, Helper, Policy); 1693 } 1694 1695 void VisitForStmt(ForStmt* F) { 1696 OS << "for (" ; 1697 if (F->getInit()) OS << "..."; 1698 OS << "; "; 1699 if (Stmt* C = F->getCond()) C->printPretty(OS, Helper, Policy); 1700 OS << "; "; 1701 if (F->getInc()) OS << "..."; 1702 OS << ")"; 1703 } 1704 1705 void VisitWhileStmt(WhileStmt* W) { 1706 OS << "while " ; 1707 if (Stmt* C = W->getCond()) C->printPretty(OS, Helper, Policy); 1708 } 1709 1710 void VisitDoStmt(DoStmt* D) { 1711 OS << "do ... while "; 1712 if (Stmt* C = D->getCond()) C->printPretty(OS, Helper, Policy); 1713 } 1714 1715 void VisitSwitchStmt(SwitchStmt* Terminator) { 1716 OS << "switch "; 1717 Terminator->getCond()->printPretty(OS, Helper, Policy); 1718 } 1719 1720 void VisitConditionalOperator(ConditionalOperator* C) { 1721 C->getCond()->printPretty(OS, Helper, Policy); 1722 OS << " ? ... : ..."; 1723 } 1724 1725 void VisitChooseExpr(ChooseExpr* C) { 1726 OS << "__builtin_choose_expr( "; 1727 C->getCond()->printPretty(OS, Helper, Policy); 1728 OS << " )"; 1729 } 1730 1731 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1732 OS << "goto *"; 1733 I->getTarget()->printPretty(OS, Helper, Policy); 1734 } 1735 1736 void VisitBinaryOperator(BinaryOperator* B) { 1737 if (!B->isLogicalOp()) { 1738 VisitExpr(B); 1739 return; 1740 } 1741 1742 B->getLHS()->printPretty(OS, Helper, Policy); 1743 1744 switch (B->getOpcode()) { 1745 case BinaryOperator::LOr: 1746 OS << " || ..."; 1747 return; 1748 case BinaryOperator::LAnd: 1749 OS << " && ..."; 1750 return; 1751 default: 1752 assert(false && "Invalid logical operator."); 1753 } 1754 } 1755 1756 void VisitExpr(Expr* E) { 1757 E->printPretty(OS, Helper, Policy); 1758 } 1759}; 1760} // end anonymous namespace 1761 1762 1763static void print_stmt(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 1764 Stmt* Terminator) { 1765 if (Helper) { 1766 // special printing for statement-expressions. 1767 if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) { 1768 CompoundStmt* Sub = SE->getSubStmt(); 1769 1770 if (Sub->child_begin() != Sub->child_end()) { 1771 OS << "({ ... ; "; 1772 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 1773 OS << " })\n"; 1774 return; 1775 } 1776 } 1777 1778 // special printing for comma expressions. 1779 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) { 1780 if (B->getOpcode() == BinaryOperator::Comma) { 1781 OS << "... , "; 1782 Helper->handledStmt(B->getRHS(),OS); 1783 OS << '\n'; 1784 return; 1785 } 1786 } 1787 } 1788 1789 Terminator->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 1790 1791 // Expressions need a newline. 1792 if (isa<Expr>(Terminator)) OS << '\n'; 1793} 1794 1795static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 1796 const CFGBlock& B, 1797 StmtPrinterHelper* Helper, bool print_edges) { 1798 1799 if (Helper) Helper->setBlockID(B.getBlockID()); 1800 1801 // Print the header. 1802 OS << "\n [ B" << B.getBlockID(); 1803 1804 if (&B == &cfg->getEntry()) 1805 OS << " (ENTRY) ]\n"; 1806 else if (&B == &cfg->getExit()) 1807 OS << " (EXIT) ]\n"; 1808 else if (&B == cfg->getIndirectGotoBlock()) 1809 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 1810 else 1811 OS << " ]\n"; 1812 1813 // Print the label of this block. 1814 if (Stmt* Terminator = const_cast<Stmt*>(B.getLabel())) { 1815 1816 if (print_edges) 1817 OS << " "; 1818 1819 if (LabelStmt* L = dyn_cast<LabelStmt>(Terminator)) 1820 OS << L->getName(); 1821 else if (CaseStmt* C = dyn_cast<CaseStmt>(Terminator)) { 1822 OS << "case "; 1823 C->getLHS()->printPretty(OS, Helper, 1824 PrintingPolicy(Helper->getLangOpts())); 1825 if (C->getRHS()) { 1826 OS << " ... "; 1827 C->getRHS()->printPretty(OS, Helper, 1828 PrintingPolicy(Helper->getLangOpts())); 1829 } 1830 } else if (isa<DefaultStmt>(Terminator)) 1831 OS << "default"; 1832 else 1833 assert(false && "Invalid label statement in CFGBlock."); 1834 1835 OS << ":\n"; 1836 } 1837 1838 // Iterate through the statements in the block and print them. 1839 unsigned j = 1; 1840 1841 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 1842 I != E ; ++I, ++j ) { 1843 1844 // Print the statement # in the basic block and the statement itself. 1845 if (print_edges) 1846 OS << " "; 1847 1848 OS << llvm::format("%3d", j) << ": "; 1849 1850 if (Helper) 1851 Helper->setStmtID(j); 1852 1853 print_stmt(OS,Helper,*I); 1854 } 1855 1856 // Print the terminator of this block. 1857 if (B.getTerminator()) { 1858 if (print_edges) 1859 OS << " "; 1860 1861 OS << " T: "; 1862 1863 if (Helper) Helper->setBlockID(-1); 1864 1865 CFGBlockTerminatorPrint TPrinter(OS, Helper, 1866 PrintingPolicy(Helper->getLangOpts())); 1867 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 1868 OS << '\n'; 1869 } 1870 1871 if (print_edges) { 1872 // Print the predecessors of this block. 1873 OS << " Predecessors (" << B.pred_size() << "):"; 1874 unsigned i = 0; 1875 1876 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 1877 I != E; ++I, ++i) { 1878 1879 if (i == 8 || (i-8) == 0) 1880 OS << "\n "; 1881 1882 OS << " B" << (*I)->getBlockID(); 1883 } 1884 1885 OS << '\n'; 1886 1887 // Print the successors of this block. 1888 OS << " Successors (" << B.succ_size() << "):"; 1889 i = 0; 1890 1891 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 1892 I != E; ++I, ++i) { 1893 1894 if (i == 8 || (i-8) % 10 == 0) 1895 OS << "\n "; 1896 1897 if (*I) 1898 OS << " B" << (*I)->getBlockID(); 1899 else 1900 OS << " NULL"; 1901 } 1902 1903 OS << '\n'; 1904 } 1905} 1906 1907 1908/// dump - A simple pretty printer of a CFG that outputs to stderr. 1909void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 1910 1911/// print - A simple pretty printer of a CFG that outputs to an ostream. 1912void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 1913 StmtPrinterHelper Helper(this, LO); 1914 1915 // Print the entry block. 1916 print_block(OS, this, getEntry(), &Helper, true); 1917 1918 // Iterate through the CFGBlocks and print them one by one. 1919 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 1920 // Skip the entry block, because we already printed it. 1921 if (&(**I) == &getEntry() || &(**I) == &getExit()) 1922 continue; 1923 1924 print_block(OS, this, **I, &Helper, true); 1925 } 1926 1927 // Print the exit block. 1928 print_block(OS, this, getExit(), &Helper, true); 1929 OS.flush(); 1930} 1931 1932/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 1933void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 1934 print(llvm::errs(), cfg, LO); 1935} 1936 1937/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 1938/// Generally this will only be called from CFG::print. 1939void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 1940 const LangOptions &LO) const { 1941 StmtPrinterHelper Helper(cfg, LO); 1942 print_block(OS, cfg, *this, &Helper, true); 1943} 1944 1945/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 1946void CFGBlock::printTerminator(llvm::raw_ostream &OS, 1947 const LangOptions &LO) const { 1948 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 1949 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 1950} 1951 1952Stmt* CFGBlock::getTerminatorCondition() { 1953 1954 if (!Terminator) 1955 return NULL; 1956 1957 Expr* E = NULL; 1958 1959 switch (Terminator->getStmtClass()) { 1960 default: 1961 break; 1962 1963 case Stmt::ForStmtClass: 1964 E = cast<ForStmt>(Terminator)->getCond(); 1965 break; 1966 1967 case Stmt::WhileStmtClass: 1968 E = cast<WhileStmt>(Terminator)->getCond(); 1969 break; 1970 1971 case Stmt::DoStmtClass: 1972 E = cast<DoStmt>(Terminator)->getCond(); 1973 break; 1974 1975 case Stmt::IfStmtClass: 1976 E = cast<IfStmt>(Terminator)->getCond(); 1977 break; 1978 1979 case Stmt::ChooseExprClass: 1980 E = cast<ChooseExpr>(Terminator)->getCond(); 1981 break; 1982 1983 case Stmt::IndirectGotoStmtClass: 1984 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 1985 break; 1986 1987 case Stmt::SwitchStmtClass: 1988 E = cast<SwitchStmt>(Terminator)->getCond(); 1989 break; 1990 1991 case Stmt::ConditionalOperatorClass: 1992 E = cast<ConditionalOperator>(Terminator)->getCond(); 1993 break; 1994 1995 case Stmt::BinaryOperatorClass: // '&&' and '||' 1996 E = cast<BinaryOperator>(Terminator)->getLHS(); 1997 break; 1998 1999 case Stmt::ObjCForCollectionStmtClass: 2000 return Terminator; 2001 } 2002 2003 return E ? E->IgnoreParens() : NULL; 2004} 2005 2006bool CFGBlock::hasBinaryBranchTerminator() const { 2007 2008 if (!Terminator) 2009 return false; 2010 2011 Expr* E = NULL; 2012 2013 switch (Terminator->getStmtClass()) { 2014 default: 2015 return false; 2016 2017 case Stmt::ForStmtClass: 2018 case Stmt::WhileStmtClass: 2019 case Stmt::DoStmtClass: 2020 case Stmt::IfStmtClass: 2021 case Stmt::ChooseExprClass: 2022 case Stmt::ConditionalOperatorClass: 2023 case Stmt::BinaryOperatorClass: 2024 return true; 2025 } 2026 2027 return E ? E->IgnoreParens() : NULL; 2028} 2029 2030 2031//===----------------------------------------------------------------------===// 2032// CFG Graphviz Visualization 2033//===----------------------------------------------------------------------===// 2034 2035 2036#ifndef NDEBUG 2037static StmtPrinterHelper* GraphHelper; 2038#endif 2039 2040void CFG::viewCFG(const LangOptions &LO) const { 2041#ifndef NDEBUG 2042 StmtPrinterHelper H(this, LO); 2043 GraphHelper = &H; 2044 llvm::ViewGraph(this,"CFG"); 2045 GraphHelper = NULL; 2046#endif 2047} 2048 2049namespace llvm { 2050template<> 2051struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2052 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph, 2053 bool ShortNames) { 2054 2055#ifndef NDEBUG 2056 std::string OutSStr; 2057 llvm::raw_string_ostream Out(OutSStr); 2058 print_block(Out,Graph, *Node, GraphHelper, false); 2059 std::string& OutStr = Out.str(); 2060 2061 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2062 2063 // Process string output to make it nicer... 2064 for (unsigned i = 0; i != OutStr.length(); ++i) 2065 if (OutStr[i] == '\n') { // Left justify 2066 OutStr[i] = '\\'; 2067 OutStr.insert(OutStr.begin()+i+1, 'l'); 2068 } 2069 2070 return OutStr; 2071#else 2072 return ""; 2073#endif 2074 } 2075}; 2076} // end namespace llvm 2077