CFG.cpp revision 198398
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/Compiler.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39/// CFGBuilder - This class implements CFG construction from an AST. 40/// The builder is stateful: an instance of the builder should be used to only 41/// construct a single CFG. 42/// 43/// Example usage: 44/// 45/// CFGBuilder builder; 46/// CFG* cfg = builder.BuildAST(stmt1); 47/// 48/// CFG construction is done via a recursive walk of an AST. We actually parse 49/// the AST in reverse order so that the successor of a basic block is 50/// constructed prior to its predecessor. This allows us to nicely capture 51/// implicit fall-throughs without extra basic blocks. 52/// 53class VISIBILITY_HIDDEN CFGBuilder { 54 ASTContext *Context; 55 llvm::OwningPtr<CFG> cfg; 56 57 CFGBlock* Block; 58 CFGBlock* Succ; 59 CFGBlock* ContinueTargetBlock; 60 CFGBlock* BreakTargetBlock; 61 CFGBlock* SwitchTerminatedBlock; 62 CFGBlock* DefaultCaseBlock; 63 64 // LabelMap records the mapping from Label expressions to their blocks. 65 typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy; 66 LabelMapTy LabelMap; 67 68 // A list of blocks that end with a "goto" that must be backpatched to their 69 // resolved targets upon completion of CFG construction. 70 typedef std::vector<CFGBlock*> BackpatchBlocksTy; 71 BackpatchBlocksTy BackpatchBlocks; 72 73 // A list of labels whose address has been taken (for indirect gotos). 74 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 75 LabelSetTy AddressTakenLabels; 76 77public: 78 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 79 Block(NULL), Succ(NULL), 80 ContinueTargetBlock(NULL), BreakTargetBlock(NULL), 81 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL) {} 82 83 // buildCFG - Used by external clients to construct the CFG. 84 CFG* buildCFG(Stmt *Statement, ASTContext *C); 85 86private: 87 // Visitors to walk an AST and construct the CFG. 88 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, bool alwaysAdd); 89 CFGBlock *VisitBinaryOperator(BinaryOperator *B, bool alwaysAdd); 90 CFGBlock *VisitBlockExpr(BlockExpr* E, bool alwaysAdd); 91 CFGBlock *VisitBlockDeclRefExpr(BlockDeclRefExpr* E, bool alwaysAdd); 92 CFGBlock *VisitBreakStmt(BreakStmt *B); 93 CFGBlock *VisitCallExpr(CallExpr *C, bool alwaysAdd); 94 CFGBlock *VisitCaseStmt(CaseStmt *C); 95 CFGBlock *VisitChooseExpr(ChooseExpr *C); 96 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 97 CFGBlock *VisitConditionalOperator(ConditionalOperator *C); 98 CFGBlock *VisitContinueStmt(ContinueStmt *C); 99 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 100 CFGBlock *VisitDeclStmt(DeclStmt *DS); 101 CFGBlock *VisitDeclSubExpr(Decl* D); 102 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 103 CFGBlock *VisitDoStmt(DoStmt *D); 104 CFGBlock *VisitForStmt(ForStmt *F); 105 CFGBlock *VisitGotoStmt(GotoStmt* G); 106 CFGBlock *VisitIfStmt(IfStmt *I); 107 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 108 CFGBlock *VisitLabelStmt(LabelStmt *L); 109 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 110 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 111 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 112 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 113 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 114 CFGBlock *VisitReturnStmt(ReturnStmt* R); 115 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, bool alwaysAdd); 116 CFGBlock *VisitStmtExpr(StmtExpr *S, bool alwaysAdd); 117 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 118 CFGBlock *VisitWhileStmt(WhileStmt *W); 119 120 CFGBlock *Visit(Stmt *S, bool alwaysAdd = false); 121 CFGBlock *VisitStmt(Stmt *S, bool alwaysAdd); 122 CFGBlock *VisitChildren(Stmt* S); 123 124 // NYS == Not Yet Supported 125 CFGBlock* NYS() { 126 badCFG = true; 127 return Block; 128 } 129 130 void autoCreateBlock() { if (!Block) Block = createBlock(); } 131 CFGBlock *createBlock(bool add_successor = true); 132 bool FinishBlock(CFGBlock* B); 133 CFGBlock *addStmt(Stmt *S) { return Visit(S, true); } 134 135 void AppendStmt(CFGBlock *B, Stmt *S) { 136 B->appendStmt(S, cfg->getBumpVectorContext()); 137 } 138 139 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 140 B->addSuccessor(S, cfg->getBumpVectorContext()); 141 } 142 143 /// TryResult - a class representing a variant over the values 144 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 145 /// and is used by the CFGBuilder to decide if a branch condition 146 /// can be decided up front during CFG construction. 147 class TryResult { 148 int X; 149 public: 150 TryResult(bool b) : X(b ? 1 : 0) {} 151 TryResult() : X(-1) {} 152 153 bool isTrue() const { return X == 1; } 154 bool isFalse() const { return X == 0; } 155 bool isKnown() const { return X >= 0; } 156 void negate() { 157 assert(isKnown()); 158 X ^= 0x1; 159 } 160 }; 161 162 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 163 /// if we can evaluate to a known value, otherwise return -1. 164 TryResult TryEvaluateBool(Expr *S) { 165 Expr::EvalResult Result; 166 if (!S->isTypeDependent() && !S->isValueDependent() && 167 S->Evaluate(Result, *Context) && Result.Val.isInt()) 168 return Result.Val.getInt().getBoolValue(); 169 170 return TryResult(); 171 } 172 173 bool badCFG; 174}; 175 176// FIXME: Add support for dependent-sized array types in C++? 177// Does it even make sense to build a CFG for an uninstantiated template? 178static VariableArrayType* FindVA(Type* t) { 179 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 180 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 181 if (vat->getSizeExpr()) 182 return vat; 183 184 t = vt->getElementType().getTypePtr(); 185 } 186 187 return 0; 188} 189 190/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 191/// arbitrary statement. Examples include a single expression or a function 192/// body (compound statement). The ownership of the returned CFG is 193/// transferred to the caller. If CFG construction fails, this method returns 194/// NULL. 195CFG* CFGBuilder::buildCFG(Stmt* Statement, ASTContext* C) { 196 Context = C; 197 assert(cfg.get()); 198 if (!Statement) 199 return NULL; 200 201 badCFG = false; 202 203 // Create an empty block that will serve as the exit block for the CFG. Since 204 // this is the first block added to the CFG, it will be implicitly registered 205 // as the exit block. 206 Succ = createBlock(); 207 assert(Succ == &cfg->getExit()); 208 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 209 210 // Visit the statements and create the CFG. 211 CFGBlock* B = addStmt(Statement); 212 if (!B) 213 B = Succ; 214 215 if (B) { 216 // Finalize the last constructed block. This usually involves reversing the 217 // order of the statements in the block. 218 if (Block) FinishBlock(B); 219 220 // Backpatch the gotos whose label -> block mappings we didn't know when we 221 // encountered them. 222 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 223 E = BackpatchBlocks.end(); I != E; ++I ) { 224 225 CFGBlock* B = *I; 226 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 227 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 228 229 // If there is no target for the goto, then we are looking at an 230 // incomplete AST. Handle this by not registering a successor. 231 if (LI == LabelMap.end()) continue; 232 233 AddSuccessor(B, LI->second); 234 } 235 236 // Add successors to the Indirect Goto Dispatch block (if we have one). 237 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 238 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 239 E = AddressTakenLabels.end(); I != E; ++I ) { 240 241 // Lookup the target block. 242 LabelMapTy::iterator LI = LabelMap.find(*I); 243 244 // If there is no target block that contains label, then we are looking 245 // at an incomplete AST. Handle this by not registering a successor. 246 if (LI == LabelMap.end()) continue; 247 248 AddSuccessor(B, LI->second); 249 } 250 251 Succ = B; 252 } 253 254 // Create an empty entry block that has no predecessors. 255 cfg->setEntry(createBlock()); 256 257 return badCFG ? NULL : cfg.take(); 258} 259 260/// createBlock - Used to lazily create blocks that are connected 261/// to the current (global) succcessor. 262CFGBlock* CFGBuilder::createBlock(bool add_successor) { 263 CFGBlock* B = cfg->createBlock(); 264 if (add_successor && Succ) 265 AddSuccessor(B, Succ); 266 return B; 267} 268 269/// FinishBlock - "Finalize" the block by checking if we have a bad CFG. 270bool CFGBuilder::FinishBlock(CFGBlock* B) { 271 if (badCFG) 272 return false; 273 274 assert(B); 275 return true; 276} 277 278/// Visit - Walk the subtree of a statement and add extra 279/// blocks for ternary operators, &&, and ||. We also process "," and 280/// DeclStmts (which may contain nested control-flow). 281CFGBlock* CFGBuilder::Visit(Stmt * S, bool alwaysAdd) { 282tryAgain: 283 switch (S->getStmtClass()) { 284 default: 285 return VisitStmt(S, alwaysAdd); 286 287 case Stmt::AddrLabelExprClass: 288 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), alwaysAdd); 289 290 case Stmt::BinaryOperatorClass: 291 return VisitBinaryOperator(cast<BinaryOperator>(S), alwaysAdd); 292 293 case Stmt::BlockExprClass: 294 return VisitBlockExpr(cast<BlockExpr>(S), alwaysAdd); 295 296 case Stmt::BlockDeclRefExprClass: 297 return VisitBlockDeclRefExpr(cast<BlockDeclRefExpr>(S), alwaysAdd); 298 299 case Stmt::BreakStmtClass: 300 return VisitBreakStmt(cast<BreakStmt>(S)); 301 302 case Stmt::CallExprClass: 303 return VisitCallExpr(cast<CallExpr>(S), alwaysAdd); 304 305 case Stmt::CaseStmtClass: 306 return VisitCaseStmt(cast<CaseStmt>(S)); 307 308 case Stmt::ChooseExprClass: 309 return VisitChooseExpr(cast<ChooseExpr>(S)); 310 311 case Stmt::CompoundStmtClass: 312 return VisitCompoundStmt(cast<CompoundStmt>(S)); 313 314 case Stmt::ConditionalOperatorClass: 315 return VisitConditionalOperator(cast<ConditionalOperator>(S)); 316 317 case Stmt::ContinueStmtClass: 318 return VisitContinueStmt(cast<ContinueStmt>(S)); 319 320 case Stmt::DeclStmtClass: 321 return VisitDeclStmt(cast<DeclStmt>(S)); 322 323 case Stmt::DefaultStmtClass: 324 return VisitDefaultStmt(cast<DefaultStmt>(S)); 325 326 case Stmt::DoStmtClass: 327 return VisitDoStmt(cast<DoStmt>(S)); 328 329 case Stmt::ForStmtClass: 330 return VisitForStmt(cast<ForStmt>(S)); 331 332 case Stmt::GotoStmtClass: 333 return VisitGotoStmt(cast<GotoStmt>(S)); 334 335 case Stmt::IfStmtClass: 336 return VisitIfStmt(cast<IfStmt>(S)); 337 338 case Stmt::IndirectGotoStmtClass: 339 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 340 341 case Stmt::LabelStmtClass: 342 return VisitLabelStmt(cast<LabelStmt>(S)); 343 344 case Stmt::ObjCAtCatchStmtClass: 345 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 346 347 case Stmt::CXXThrowExprClass: 348 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 349 350 case Stmt::ObjCAtSynchronizedStmtClass: 351 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 352 353 case Stmt::ObjCAtThrowStmtClass: 354 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 355 356 case Stmt::ObjCAtTryStmtClass: 357 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 358 359 case Stmt::ObjCForCollectionStmtClass: 360 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 361 362 case Stmt::ParenExprClass: 363 S = cast<ParenExpr>(S)->getSubExpr(); 364 goto tryAgain; 365 366 case Stmt::NullStmtClass: 367 return Block; 368 369 case Stmt::ReturnStmtClass: 370 return VisitReturnStmt(cast<ReturnStmt>(S)); 371 372 case Stmt::SizeOfAlignOfExprClass: 373 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), alwaysAdd); 374 375 case Stmt::StmtExprClass: 376 return VisitStmtExpr(cast<StmtExpr>(S), alwaysAdd); 377 378 case Stmt::SwitchStmtClass: 379 return VisitSwitchStmt(cast<SwitchStmt>(S)); 380 381 case Stmt::WhileStmtClass: 382 return VisitWhileStmt(cast<WhileStmt>(S)); 383 } 384} 385 386CFGBlock *CFGBuilder::VisitStmt(Stmt *S, bool alwaysAdd) { 387 if (alwaysAdd) { 388 autoCreateBlock(); 389 AppendStmt(Block, S); 390 } 391 392 return VisitChildren(S); 393} 394 395/// VisitChildren - Visit the children of a Stmt. 396CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 397 CFGBlock *B = Block; 398 for (Stmt::child_iterator I = Terminator->child_begin(), 399 E = Terminator->child_end(); I != E; ++I) { 400 if (*I) B = Visit(*I); 401 } 402 return B; 403} 404 405CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, bool alwaysAdd) { 406 AddressTakenLabels.insert(A->getLabel()); 407 408 if (alwaysAdd) { 409 autoCreateBlock(); 410 AppendStmt(Block, A); 411 } 412 413 return Block; 414} 415 416CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, bool alwaysAdd) { 417 if (B->isLogicalOp()) { // && or || 418 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 419 AppendStmt(ConfluenceBlock, B); 420 421 if (!FinishBlock(ConfluenceBlock)) 422 return 0; 423 424 // create the block evaluating the LHS 425 CFGBlock* LHSBlock = createBlock(false); 426 LHSBlock->setTerminator(B); 427 428 // create the block evaluating the RHS 429 Succ = ConfluenceBlock; 430 Block = NULL; 431 CFGBlock* RHSBlock = addStmt(B->getRHS()); 432 if (!FinishBlock(RHSBlock)) 433 return 0; 434 435 // See if this is a known constant. 436 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 437 if (KnownVal.isKnown() && (B->getOpcode() == BinaryOperator::LOr)) 438 KnownVal.negate(); 439 440 // Now link the LHSBlock with RHSBlock. 441 if (B->getOpcode() == BinaryOperator::LOr) { 442 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 443 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 444 } else { 445 assert (B->getOpcode() == BinaryOperator::LAnd); 446 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 447 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 448 } 449 450 // Generate the blocks for evaluating the LHS. 451 Block = LHSBlock; 452 return addStmt(B->getLHS()); 453 } 454 else if (B->getOpcode() == BinaryOperator::Comma) { // , 455 autoCreateBlock(); 456 AppendStmt(Block, B); 457 addStmt(B->getRHS()); 458 return addStmt(B->getLHS()); 459 } 460 461 return VisitStmt(B, alwaysAdd); 462} 463 464CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr* E, bool alwaysAdd) { 465 // FIXME 466 return NYS(); 467} 468 469CFGBlock *CFGBuilder::VisitBlockDeclRefExpr(BlockDeclRefExpr* E, 470 bool alwaysAdd) { 471 // FIXME 472 return NYS(); 473} 474 475CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 476 // "break" is a control-flow statement. Thus we stop processing the current 477 // block. 478 if (Block && !FinishBlock(Block)) 479 return 0; 480 481 // Now create a new block that ends with the break statement. 482 Block = createBlock(false); 483 Block->setTerminator(B); 484 485 // If there is no target for the break, then we are looking at an incomplete 486 // AST. This means that the CFG cannot be constructed. 487 if (BreakTargetBlock) 488 AddSuccessor(Block, BreakTargetBlock); 489 else 490 badCFG = true; 491 492 493 return Block; 494} 495 496CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, bool alwaysAdd) { 497 // If this is a call to a no-return function, this stops the block here. 498 bool NoReturn = false; 499 if (C->getCallee()->getType().getNoReturnAttr()) { 500 NoReturn = true; 501 } 502 503 if (FunctionDecl *FD = C->getDirectCallee()) 504 if (FD->hasAttr<NoReturnAttr>()) 505 NoReturn = true; 506 507 if (!NoReturn) 508 return VisitStmt(C, alwaysAdd); 509 510 if (Block && !FinishBlock(Block)) 511 return 0; 512 513 // Create new block with no successor for the remaining pieces. 514 Block = createBlock(false); 515 AppendStmt(Block, C); 516 517 // Wire this to the exit block directly. 518 AddSuccessor(Block, &cfg->getExit()); 519 520 return VisitChildren(C); 521} 522 523CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C) { 524 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 525 AppendStmt(ConfluenceBlock, C); 526 if (!FinishBlock(ConfluenceBlock)) 527 return 0; 528 529 Succ = ConfluenceBlock; 530 Block = NULL; 531 CFGBlock* LHSBlock = addStmt(C->getLHS()); 532 if (!FinishBlock(LHSBlock)) 533 return 0; 534 535 Succ = ConfluenceBlock; 536 Block = NULL; 537 CFGBlock* RHSBlock = addStmt(C->getRHS()); 538 if (!FinishBlock(RHSBlock)) 539 return 0; 540 541 Block = createBlock(false); 542 // See if this is a known constant. 543 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 544 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 545 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 546 Block->setTerminator(C); 547 return addStmt(C->getCond()); 548} 549 550 551CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 552 CFGBlock* LastBlock = Block; 553 554 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 555 I != E; ++I ) { 556 LastBlock = addStmt(*I); 557 558 if (badCFG) 559 return NULL; 560 } 561 return LastBlock; 562} 563 564CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C) { 565 // Create the confluence block that will "merge" the results of the ternary 566 // expression. 567 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 568 AppendStmt(ConfluenceBlock, C); 569 if (!FinishBlock(ConfluenceBlock)) 570 return 0; 571 572 // Create a block for the LHS expression if there is an LHS expression. A 573 // GCC extension allows LHS to be NULL, causing the condition to be the 574 // value that is returned instead. 575 // e.g: x ?: y is shorthand for: x ? x : y; 576 Succ = ConfluenceBlock; 577 Block = NULL; 578 CFGBlock* LHSBlock = NULL; 579 if (C->getLHS()) { 580 LHSBlock = addStmt(C->getLHS()); 581 if (!FinishBlock(LHSBlock)) 582 return 0; 583 Block = NULL; 584 } 585 586 // Create the block for the RHS expression. 587 Succ = ConfluenceBlock; 588 CFGBlock* RHSBlock = addStmt(C->getRHS()); 589 if (!FinishBlock(RHSBlock)) 590 return 0; 591 592 // Create the block that will contain the condition. 593 Block = createBlock(false); 594 595 // See if this is a known constant. 596 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 597 if (LHSBlock) { 598 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 599 } else { 600 if (KnownVal.isFalse()) { 601 // If we know the condition is false, add NULL as the successor for 602 // the block containing the condition. In this case, the confluence 603 // block will have just one predecessor. 604 AddSuccessor(Block, 0); 605 assert(ConfluenceBlock->pred_size() == 1); 606 } else { 607 // If we have no LHS expression, add the ConfluenceBlock as a direct 608 // successor for the block containing the condition. Moreover, we need to 609 // reverse the order of the predecessors in the ConfluenceBlock because 610 // the RHSBlock will have been added to the succcessors already, and we 611 // want the first predecessor to the the block containing the expression 612 // for the case when the ternary expression evaluates to true. 613 AddSuccessor(Block, ConfluenceBlock); 614 assert(ConfluenceBlock->pred_size() == 2); 615 std::reverse(ConfluenceBlock->pred_begin(), 616 ConfluenceBlock->pred_end()); 617 } 618 } 619 620 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 621 Block->setTerminator(C); 622 return addStmt(C->getCond()); 623} 624 625CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 626 autoCreateBlock(); 627 628 if (DS->isSingleDecl()) { 629 AppendStmt(Block, DS); 630 return VisitDeclSubExpr(DS->getSingleDecl()); 631 } 632 633 CFGBlock *B = 0; 634 635 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 636 typedef llvm::SmallVector<Decl*,10> BufTy; 637 BufTy Buf(DS->decl_begin(), DS->decl_end()); 638 639 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 640 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 641 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 642 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 643 644 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 645 // automatically freed with the CFG. 646 DeclGroupRef DG(*I); 647 Decl *D = *I; 648 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 649 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 650 651 // Append the fake DeclStmt to block. 652 AppendStmt(Block, DSNew); 653 B = VisitDeclSubExpr(D); 654 } 655 656 return B; 657} 658 659/// VisitDeclSubExpr - Utility method to add block-level expressions for 660/// initializers in Decls. 661CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 662 assert(Block); 663 664 VarDecl *VD = dyn_cast<VarDecl>(D); 665 666 if (!VD) 667 return Block; 668 669 Expr *Init = VD->getInit(); 670 671 if (Init) { 672 // Optimization: Don't create separate block-level statements for literals. 673 switch (Init->getStmtClass()) { 674 case Stmt::IntegerLiteralClass: 675 case Stmt::CharacterLiteralClass: 676 case Stmt::StringLiteralClass: 677 break; 678 default: 679 Block = addStmt(Init); 680 } 681 } 682 683 // If the type of VD is a VLA, then we must process its size expressions. 684 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 685 VA = FindVA(VA->getElementType().getTypePtr())) 686 Block = addStmt(VA->getSizeExpr()); 687 688 return Block; 689} 690 691CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 692 // We may see an if statement in the middle of a basic block, or it may be the 693 // first statement we are processing. In either case, we create a new basic 694 // block. First, we create the blocks for the then...else statements, and 695 // then we create the block containing the if statement. If we were in the 696 // middle of a block, we stop processing that block. That block is then the 697 // implicit successor for the "then" and "else" clauses. 698 699 // The block we were proccessing is now finished. Make it the successor 700 // block. 701 if (Block) { 702 Succ = Block; 703 if (!FinishBlock(Block)) 704 return 0; 705 } 706 707 // Process the false branch. 708 CFGBlock* ElseBlock = Succ; 709 710 if (Stmt* Else = I->getElse()) { 711 SaveAndRestore<CFGBlock*> sv(Succ); 712 713 // NULL out Block so that the recursive call to Visit will 714 // create a new basic block. 715 Block = NULL; 716 ElseBlock = addStmt(Else); 717 718 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 719 ElseBlock = sv.get(); 720 else if (Block) { 721 if (!FinishBlock(ElseBlock)) 722 return 0; 723 } 724 } 725 726 // Process the true branch. 727 CFGBlock* ThenBlock; 728 { 729 Stmt* Then = I->getThen(); 730 assert (Then); 731 SaveAndRestore<CFGBlock*> sv(Succ); 732 Block = NULL; 733 ThenBlock = addStmt(Then); 734 735 if (!ThenBlock) { 736 // We can reach here if the "then" body has all NullStmts. 737 // Create an empty block so we can distinguish between true and false 738 // branches in path-sensitive analyses. 739 ThenBlock = createBlock(false); 740 AddSuccessor(ThenBlock, sv.get()); 741 } else if (Block) { 742 if (!FinishBlock(ThenBlock)) 743 return 0; 744 } 745 } 746 747 // Now create a new block containing the if statement. 748 Block = createBlock(false); 749 750 // Set the terminator of the new block to the If statement. 751 Block->setTerminator(I); 752 753 // See if this is a known constant. 754 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 755 756 // Now add the successors. 757 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 758 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 759 760 // Add the condition as the last statement in the new block. This may create 761 // new blocks as the condition may contain control-flow. Any newly created 762 // blocks will be pointed to be "Block". 763 return addStmt(I->getCond()); 764} 765 766 767CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 768 // If we were in the middle of a block we stop processing that block. 769 // 770 // NOTE: If a "return" appears in the middle of a block, this means that the 771 // code afterwards is DEAD (unreachable). We still keep a basic block 772 // for that code; a simple "mark-and-sweep" from the entry block will be 773 // able to report such dead blocks. 774 if (Block) 775 FinishBlock(Block); 776 777 // Create the new block. 778 Block = createBlock(false); 779 780 // The Exit block is the only successor. 781 AddSuccessor(Block, &cfg->getExit()); 782 783 // Add the return statement to the block. This may create new blocks if R 784 // contains control-flow (short-circuit operations). 785 return VisitStmt(R, true); 786} 787 788CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 789 // Get the block of the labeled statement. Add it to our map. 790 addStmt(L->getSubStmt()); 791 CFGBlock* LabelBlock = Block; 792 793 if (!LabelBlock) // This can happen when the body is empty, i.e. 794 LabelBlock = createBlock(); // scopes that only contains NullStmts. 795 796 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 797 LabelMap[ L ] = LabelBlock; 798 799 // Labels partition blocks, so this is the end of the basic block we were 800 // processing (L is the block's label). Because this is label (and we have 801 // already processed the substatement) there is no extra control-flow to worry 802 // about. 803 LabelBlock->setLabel(L); 804 if (!FinishBlock(LabelBlock)) 805 return 0; 806 807 // We set Block to NULL to allow lazy creation of a new block (if necessary); 808 Block = NULL; 809 810 // This block is now the implicit successor of other blocks. 811 Succ = LabelBlock; 812 813 return LabelBlock; 814} 815 816CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 817 // Goto is a control-flow statement. Thus we stop processing the current 818 // block and create a new one. 819 if (Block) 820 FinishBlock(Block); 821 822 Block = createBlock(false); 823 Block->setTerminator(G); 824 825 // If we already know the mapping to the label block add the successor now. 826 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 827 828 if (I == LabelMap.end()) 829 // We will need to backpatch this block later. 830 BackpatchBlocks.push_back(Block); 831 else 832 AddSuccessor(Block, I->second); 833 834 return Block; 835} 836 837CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 838 CFGBlock* LoopSuccessor = NULL; 839 840 // "for" is a control-flow statement. Thus we stop processing the current 841 // block. 842 if (Block) { 843 if (!FinishBlock(Block)) 844 return 0; 845 LoopSuccessor = Block; 846 } else 847 LoopSuccessor = Succ; 848 849 // Because of short-circuit evaluation, the condition of the loop can span 850 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 851 // evaluate the condition. 852 CFGBlock* ExitConditionBlock = createBlock(false); 853 CFGBlock* EntryConditionBlock = ExitConditionBlock; 854 855 // Set the terminator for the "exit" condition block. 856 ExitConditionBlock->setTerminator(F); 857 858 // Now add the actual condition to the condition block. Because the condition 859 // itself may contain control-flow, new blocks may be created. 860 if (Stmt* C = F->getCond()) { 861 Block = ExitConditionBlock; 862 EntryConditionBlock = addStmt(C); 863 if (Block) { 864 if (!FinishBlock(EntryConditionBlock)) 865 return 0; 866 } 867 } 868 869 // The condition block is the implicit successor for the loop body as well as 870 // any code above the loop. 871 Succ = EntryConditionBlock; 872 873 // See if this is a known constant. 874 TryResult KnownVal(true); 875 876 if (F->getCond()) 877 KnownVal = TryEvaluateBool(F->getCond()); 878 879 // Now create the loop body. 880 { 881 assert (F->getBody()); 882 883 // Save the current values for Block, Succ, and continue and break targets 884 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 885 save_continue(ContinueTargetBlock), 886 save_break(BreakTargetBlock); 887 888 // Create a new block to contain the (bottom) of the loop body. 889 Block = NULL; 890 891 if (Stmt* I = F->getInc()) { 892 // Generate increment code in its own basic block. This is the target of 893 // continue statements. 894 Succ = addStmt(I); 895 } else { 896 // No increment code. Create a special, empty, block that is used as the 897 // target block for "looping back" to the start of the loop. 898 assert(Succ == EntryConditionBlock); 899 Succ = createBlock(); 900 } 901 902 // Finish up the increment (or empty) block if it hasn't been already. 903 if (Block) { 904 assert(Block == Succ); 905 if (!FinishBlock(Block)) 906 return 0; 907 Block = 0; 908 } 909 910 ContinueTargetBlock = Succ; 911 912 // The starting block for the loop increment is the block that should 913 // represent the 'loop target' for looping back to the start of the loop. 914 ContinueTargetBlock->setLoopTarget(F); 915 916 // All breaks should go to the code following the loop. 917 BreakTargetBlock = LoopSuccessor; 918 919 // Now populate the body block, and in the process create new blocks as we 920 // walk the body of the loop. 921 CFGBlock* BodyBlock = addStmt(F->getBody()); 922 923 if (!BodyBlock) 924 BodyBlock = ContinueTargetBlock; // can happen for "for (...;...;...) ;" 925 else if (Block && !FinishBlock(BodyBlock)) 926 return 0; 927 928 // This new body block is a successor to our "exit" condition block. 929 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 930 } 931 932 // Link up the condition block with the code that follows the loop. (the 933 // false branch). 934 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 935 936 // If the loop contains initialization, create a new block for those 937 // statements. This block can also contain statements that precede the loop. 938 if (Stmt* I = F->getInit()) { 939 Block = createBlock(); 940 return addStmt(I); 941 } else { 942 // There is no loop initialization. We are thus basically a while loop. 943 // NULL out Block to force lazy block construction. 944 Block = NULL; 945 Succ = EntryConditionBlock; 946 return EntryConditionBlock; 947 } 948} 949 950CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 951 // Objective-C fast enumeration 'for' statements: 952 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 953 // 954 // for ( Type newVariable in collection_expression ) { statements } 955 // 956 // becomes: 957 // 958 // prologue: 959 // 1. collection_expression 960 // T. jump to loop_entry 961 // loop_entry: 962 // 1. side-effects of element expression 963 // 1. ObjCForCollectionStmt [performs binding to newVariable] 964 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 965 // TB: 966 // statements 967 // T. jump to loop_entry 968 // FB: 969 // what comes after 970 // 971 // and 972 // 973 // Type existingItem; 974 // for ( existingItem in expression ) { statements } 975 // 976 // becomes: 977 // 978 // the same with newVariable replaced with existingItem; the binding works 979 // the same except that for one ObjCForCollectionStmt::getElement() returns 980 // a DeclStmt and the other returns a DeclRefExpr. 981 // 982 983 CFGBlock* LoopSuccessor = 0; 984 985 if (Block) { 986 if (!FinishBlock(Block)) 987 return 0; 988 LoopSuccessor = Block; 989 Block = 0; 990 } else 991 LoopSuccessor = Succ; 992 993 // Build the condition blocks. 994 CFGBlock* ExitConditionBlock = createBlock(false); 995 CFGBlock* EntryConditionBlock = ExitConditionBlock; 996 997 // Set the terminator for the "exit" condition block. 998 ExitConditionBlock->setTerminator(S); 999 1000 // The last statement in the block should be the ObjCForCollectionStmt, which 1001 // performs the actual binding to 'element' and determines if there are any 1002 // more items in the collection. 1003 AppendStmt(ExitConditionBlock, S); 1004 Block = ExitConditionBlock; 1005 1006 // Walk the 'element' expression to see if there are any side-effects. We 1007 // generate new blocks as necesary. We DON'T add the statement by default to 1008 // the CFG unless it contains control-flow. 1009 EntryConditionBlock = Visit(S->getElement(), false); 1010 if (Block) { 1011 if (!FinishBlock(EntryConditionBlock)) 1012 return 0; 1013 Block = 0; 1014 } 1015 1016 // The condition block is the implicit successor for the loop body as well as 1017 // any code above the loop. 1018 Succ = EntryConditionBlock; 1019 1020 // Now create the true branch. 1021 { 1022 // Save the current values for Succ, continue and break targets. 1023 SaveAndRestore<CFGBlock*> save_Succ(Succ), 1024 save_continue(ContinueTargetBlock), save_break(BreakTargetBlock); 1025 1026 BreakTargetBlock = LoopSuccessor; 1027 ContinueTargetBlock = EntryConditionBlock; 1028 1029 CFGBlock* BodyBlock = addStmt(S->getBody()); 1030 1031 if (!BodyBlock) 1032 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1033 else if (Block) { 1034 if (!FinishBlock(BodyBlock)) 1035 return 0; 1036 } 1037 1038 // This new body block is a successor to our "exit" condition block. 1039 AddSuccessor(ExitConditionBlock, BodyBlock); 1040 } 1041 1042 // Link up the condition block with the code that follows the loop. 1043 // (the false branch). 1044 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1045 1046 // Now create a prologue block to contain the collection expression. 1047 Block = createBlock(); 1048 return addStmt(S->getCollection()); 1049} 1050 1051CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1052 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1053 1054 // Inline the body. 1055 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1056 1057 // The sync body starts its own basic block. This makes it a little easier 1058 // for diagnostic clients. 1059 if (SyncBlock) { 1060 if (!FinishBlock(SyncBlock)) 1061 return 0; 1062 1063 Block = 0; 1064 } 1065 1066 Succ = SyncBlock; 1067 1068 // Inline the sync expression. 1069 return addStmt(S->getSynchExpr()); 1070} 1071 1072CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1073 // FIXME 1074 return NYS(); 1075} 1076 1077CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1078 CFGBlock* LoopSuccessor = NULL; 1079 1080 // "while" is a control-flow statement. Thus we stop processing the current 1081 // block. 1082 if (Block) { 1083 if (!FinishBlock(Block)) 1084 return 0; 1085 LoopSuccessor = Block; 1086 } else 1087 LoopSuccessor = Succ; 1088 1089 // Because of short-circuit evaluation, the condition of the loop can span 1090 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1091 // evaluate the condition. 1092 CFGBlock* ExitConditionBlock = createBlock(false); 1093 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1094 1095 // Set the terminator for the "exit" condition block. 1096 ExitConditionBlock->setTerminator(W); 1097 1098 // Now add the actual condition to the condition block. Because the condition 1099 // itself may contain control-flow, new blocks may be created. Thus we update 1100 // "Succ" after adding the condition. 1101 if (Stmt* C = W->getCond()) { 1102 Block = ExitConditionBlock; 1103 EntryConditionBlock = addStmt(C); 1104 assert(Block == EntryConditionBlock); 1105 if (Block) { 1106 if (!FinishBlock(EntryConditionBlock)) 1107 return 0; 1108 } 1109 } 1110 1111 // The condition block is the implicit successor for the loop body as well as 1112 // any code above the loop. 1113 Succ = EntryConditionBlock; 1114 1115 // See if this is a known constant. 1116 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1117 1118 // Process the loop body. 1119 { 1120 assert(W->getBody()); 1121 1122 // Save the current values for Block, Succ, and continue and break targets 1123 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1124 save_continue(ContinueTargetBlock), 1125 save_break(BreakTargetBlock); 1126 1127 // Create an empty block to represent the transition block for looping back 1128 // to the head of the loop. 1129 Block = 0; 1130 assert(Succ == EntryConditionBlock); 1131 Succ = createBlock(); 1132 Succ->setLoopTarget(W); 1133 ContinueTargetBlock = Succ; 1134 1135 // All breaks should go to the code following the loop. 1136 BreakTargetBlock = LoopSuccessor; 1137 1138 // NULL out Block to force lazy instantiation of blocks for the body. 1139 Block = NULL; 1140 1141 // Create the body. The returned block is the entry to the loop body. 1142 CFGBlock* BodyBlock = addStmt(W->getBody()); 1143 1144 if (!BodyBlock) 1145 BodyBlock = ContinueTargetBlock; // can happen for "while(...) ;" 1146 else if (Block) { 1147 if (!FinishBlock(BodyBlock)) 1148 return 0; 1149 } 1150 1151 // Add the loop body entry as a successor to the condition. 1152 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1153 } 1154 1155 // Link up the condition block with the code that follows the loop. (the 1156 // false branch). 1157 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1158 1159 // There can be no more statements in the condition block since we loop back 1160 // to this block. NULL out Block to force lazy creation of another block. 1161 Block = NULL; 1162 1163 // Return the condition block, which is the dominating block for the loop. 1164 Succ = EntryConditionBlock; 1165 return EntryConditionBlock; 1166} 1167 1168 1169CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1170 // FIXME: For now we pretend that @catch and the code it contains does not 1171 // exit. 1172 return Block; 1173} 1174 1175CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1176 // FIXME: This isn't complete. We basically treat @throw like a return 1177 // statement. 1178 1179 // If we were in the middle of a block we stop processing that block. 1180 if (Block && !FinishBlock(Block)) 1181 return 0; 1182 1183 // Create the new block. 1184 Block = createBlock(false); 1185 1186 // The Exit block is the only successor. 1187 AddSuccessor(Block, &cfg->getExit()); 1188 1189 // Add the statement to the block. This may create new blocks if S contains 1190 // control-flow (short-circuit operations). 1191 return VisitStmt(S, true); 1192} 1193 1194CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1195 // If we were in the middle of a block we stop processing that block. 1196 if (Block && !FinishBlock(Block)) 1197 return 0; 1198 1199 // Create the new block. 1200 Block = createBlock(false); 1201 1202 // The Exit block is the only successor. 1203 AddSuccessor(Block, &cfg->getExit()); 1204 1205 // Add the statement to the block. This may create new blocks if S contains 1206 // control-flow (short-circuit operations). 1207 return VisitStmt(T, true); 1208} 1209 1210CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1211 CFGBlock* LoopSuccessor = NULL; 1212 1213 // "do...while" is a control-flow statement. Thus we stop processing the 1214 // current block. 1215 if (Block) { 1216 if (!FinishBlock(Block)) 1217 return 0; 1218 LoopSuccessor = Block; 1219 } else 1220 LoopSuccessor = Succ; 1221 1222 // Because of short-circuit evaluation, the condition of the loop can span 1223 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1224 // evaluate the condition. 1225 CFGBlock* ExitConditionBlock = createBlock(false); 1226 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1227 1228 // Set the terminator for the "exit" condition block. 1229 ExitConditionBlock->setTerminator(D); 1230 1231 // Now add the actual condition to the condition block. Because the condition 1232 // itself may contain control-flow, new blocks may be created. 1233 if (Stmt* C = D->getCond()) { 1234 Block = ExitConditionBlock; 1235 EntryConditionBlock = addStmt(C); 1236 if (Block) { 1237 if (!FinishBlock(EntryConditionBlock)) 1238 return 0; 1239 } 1240 } 1241 1242 // The condition block is the implicit successor for the loop body. 1243 Succ = EntryConditionBlock; 1244 1245 // See if this is a known constant. 1246 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1247 1248 // Process the loop body. 1249 CFGBlock* BodyBlock = NULL; 1250 { 1251 assert (D->getBody()); 1252 1253 // Save the current values for Block, Succ, and continue and break targets 1254 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1255 save_continue(ContinueTargetBlock), 1256 save_break(BreakTargetBlock); 1257 1258 // All continues within this loop should go to the condition block 1259 ContinueTargetBlock = EntryConditionBlock; 1260 1261 // All breaks should go to the code following the loop. 1262 BreakTargetBlock = LoopSuccessor; 1263 1264 // NULL out Block to force lazy instantiation of blocks for the body. 1265 Block = NULL; 1266 1267 // Create the body. The returned block is the entry to the loop body. 1268 BodyBlock = addStmt(D->getBody()); 1269 1270 if (!BodyBlock) 1271 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1272 else if (Block) { 1273 if (!FinishBlock(BodyBlock)) 1274 return 0; 1275 } 1276 1277 // Add an intermediate block between the BodyBlock and the 1278 // ExitConditionBlock to represent the "loop back" transition. Create an 1279 // empty block to represent the transition block for looping back to the 1280 // head of the loop. 1281 // FIXME: Can we do this more efficiently without adding another block? 1282 Block = NULL; 1283 Succ = BodyBlock; 1284 CFGBlock *LoopBackBlock = createBlock(); 1285 LoopBackBlock->setLoopTarget(D); 1286 1287 // Add the loop body entry as a successor to the condition. 1288 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : LoopBackBlock); 1289 } 1290 1291 // Link up the condition block with the code that follows the loop. 1292 // (the false branch). 1293 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1294 1295 // There can be no more statements in the body block(s) since we loop back to 1296 // the body. NULL out Block to force lazy creation of another block. 1297 Block = NULL; 1298 1299 // Return the loop body, which is the dominating block for the loop. 1300 Succ = BodyBlock; 1301 return BodyBlock; 1302} 1303 1304CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1305 // "continue" is a control-flow statement. Thus we stop processing the 1306 // current block. 1307 if (Block && !FinishBlock(Block)) 1308 return 0; 1309 1310 // Now create a new block that ends with the continue statement. 1311 Block = createBlock(false); 1312 Block->setTerminator(C); 1313 1314 // If there is no target for the continue, then we are looking at an 1315 // incomplete AST. This means the CFG cannot be constructed. 1316 if (ContinueTargetBlock) 1317 AddSuccessor(Block, ContinueTargetBlock); 1318 else 1319 badCFG = true; 1320 1321 return Block; 1322} 1323 1324CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1325 bool alwaysAdd) { 1326 1327 if (alwaysAdd) { 1328 autoCreateBlock(); 1329 AppendStmt(Block, E); 1330 } 1331 1332 // VLA types have expressions that must be evaluated. 1333 if (E->isArgumentType()) { 1334 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1335 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1336 addStmt(VA->getSizeExpr()); 1337 } 1338 1339 return Block; 1340} 1341 1342/// VisitStmtExpr - Utility method to handle (nested) statement 1343/// expressions (a GCC extension). 1344CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, bool alwaysAdd) { 1345 if (alwaysAdd) { 1346 autoCreateBlock(); 1347 AppendStmt(Block, SE); 1348 } 1349 return VisitCompoundStmt(SE->getSubStmt()); 1350} 1351 1352CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1353 // "switch" is a control-flow statement. Thus we stop processing the current 1354 // block. 1355 CFGBlock* SwitchSuccessor = NULL; 1356 1357 if (Block) { 1358 if (!FinishBlock(Block)) 1359 return 0; 1360 SwitchSuccessor = Block; 1361 } else SwitchSuccessor = Succ; 1362 1363 // Save the current "switch" context. 1364 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1365 save_break(BreakTargetBlock), 1366 save_default(DefaultCaseBlock); 1367 1368 // Set the "default" case to be the block after the switch statement. If the 1369 // switch statement contains a "default:", this value will be overwritten with 1370 // the block for that code. 1371 DefaultCaseBlock = SwitchSuccessor; 1372 1373 // Create a new block that will contain the switch statement. 1374 SwitchTerminatedBlock = createBlock(false); 1375 1376 // Now process the switch body. The code after the switch is the implicit 1377 // successor. 1378 Succ = SwitchSuccessor; 1379 BreakTargetBlock = SwitchSuccessor; 1380 1381 // When visiting the body, the case statements should automatically get linked 1382 // up to the switch. We also don't keep a pointer to the body, since all 1383 // control-flow from the switch goes to case/default statements. 1384 assert (Terminator->getBody() && "switch must contain a non-NULL body"); 1385 Block = NULL; 1386 CFGBlock *BodyBlock = addStmt(Terminator->getBody()); 1387 if (Block) { 1388 if (!FinishBlock(BodyBlock)) 1389 return 0; 1390 } 1391 1392 // If we have no "default:" case, the default transition is to the code 1393 // following the switch body. 1394 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1395 1396 // Add the terminator and condition in the switch block. 1397 SwitchTerminatedBlock->setTerminator(Terminator); 1398 assert (Terminator->getCond() && "switch condition must be non-NULL"); 1399 Block = SwitchTerminatedBlock; 1400 1401 return addStmt(Terminator->getCond()); 1402} 1403 1404CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1405 // CaseStmts are essentially labels, so they are the first statement in a 1406 // block. 1407 1408 if (CS->getSubStmt()) 1409 addStmt(CS->getSubStmt()); 1410 1411 CFGBlock* CaseBlock = Block; 1412 if (!CaseBlock) 1413 CaseBlock = createBlock(); 1414 1415 // Cases statements partition blocks, so this is the top of the basic block we 1416 // were processing (the "case XXX:" is the label). 1417 CaseBlock->setLabel(CS); 1418 1419 if (!FinishBlock(CaseBlock)) 1420 return 0; 1421 1422 // Add this block to the list of successors for the block with the switch 1423 // statement. 1424 assert(SwitchTerminatedBlock); 1425 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 1426 1427 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1428 Block = NULL; 1429 1430 // This block is now the implicit successor of other blocks. 1431 Succ = CaseBlock; 1432 1433 return CaseBlock; 1434} 1435 1436CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 1437 if (Terminator->getSubStmt()) 1438 addStmt(Terminator->getSubStmt()); 1439 1440 DefaultCaseBlock = Block; 1441 1442 if (!DefaultCaseBlock) 1443 DefaultCaseBlock = createBlock(); 1444 1445 // Default statements partition blocks, so this is the top of the basic block 1446 // we were processing (the "default:" is the label). 1447 DefaultCaseBlock->setLabel(Terminator); 1448 1449 if (!FinishBlock(DefaultCaseBlock)) 1450 return 0; 1451 1452 // Unlike case statements, we don't add the default block to the successors 1453 // for the switch statement immediately. This is done when we finish 1454 // processing the switch statement. This allows for the default case 1455 // (including a fall-through to the code after the switch statement) to always 1456 // be the last successor of a switch-terminated block. 1457 1458 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1459 Block = NULL; 1460 1461 // This block is now the implicit successor of other blocks. 1462 Succ = DefaultCaseBlock; 1463 1464 return DefaultCaseBlock; 1465} 1466 1467CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1468 // Lazily create the indirect-goto dispatch block if there isn't one already. 1469 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 1470 1471 if (!IBlock) { 1472 IBlock = createBlock(false); 1473 cfg->setIndirectGotoBlock(IBlock); 1474 } 1475 1476 // IndirectGoto is a control-flow statement. Thus we stop processing the 1477 // current block and create a new one. 1478 if (Block && !FinishBlock(Block)) 1479 return 0; 1480 1481 Block = createBlock(false); 1482 Block->setTerminator(I); 1483 AddSuccessor(Block, IBlock); 1484 return addStmt(I->getTarget()); 1485} 1486 1487} // end anonymous namespace 1488 1489/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 1490/// no successors or predecessors. If this is the first block created in the 1491/// CFG, it is automatically set to be the Entry and Exit of the CFG. 1492CFGBlock* CFG::createBlock() { 1493 bool first_block = begin() == end(); 1494 1495 // Create the block. 1496 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 1497 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 1498 Blocks.push_back(Mem, BlkBVC); 1499 1500 // If this is the first block, set it as the Entry and Exit. 1501 if (first_block) 1502 Entry = Exit = &back(); 1503 1504 // Return the block. 1505 return &back(); 1506} 1507 1508/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 1509/// CFG is returned to the caller. 1510CFG* CFG::buildCFG(Stmt* Statement, ASTContext *C) { 1511 CFGBuilder Builder; 1512 return Builder.buildCFG(Statement, C); 1513} 1514 1515//===----------------------------------------------------------------------===// 1516// CFG: Queries for BlkExprs. 1517//===----------------------------------------------------------------------===// 1518 1519namespace { 1520 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 1521} 1522 1523static void FindSubExprAssignments(Stmt* Terminator, llvm::SmallPtrSet<Expr*,50>& Set) { 1524 if (!Terminator) 1525 return; 1526 1527 for (Stmt::child_iterator I=Terminator->child_begin(), E=Terminator->child_end(); I!=E; ++I) { 1528 if (!*I) continue; 1529 1530 if (BinaryOperator* B = dyn_cast<BinaryOperator>(*I)) 1531 if (B->isAssignmentOp()) Set.insert(B); 1532 1533 FindSubExprAssignments(*I, Set); 1534 } 1535} 1536 1537static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 1538 BlkExprMapTy* M = new BlkExprMapTy(); 1539 1540 // Look for assignments that are used as subexpressions. These are the only 1541 // assignments that we want to *possibly* register as a block-level 1542 // expression. Basically, if an assignment occurs both in a subexpression and 1543 // at the block-level, it is a block-level expression. 1544 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 1545 1546 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 1547 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1548 FindSubExprAssignments(*BI, SubExprAssignments); 1549 1550 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 1551 1552 // Iterate over the statements again on identify the Expr* and Stmt* at the 1553 // block-level that are block-level expressions. 1554 1555 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1556 if (Expr* Exp = dyn_cast<Expr>(*BI)) { 1557 1558 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 1559 // Assignment expressions that are not nested within another 1560 // expression are really "statements" whose value is never used by 1561 // another expression. 1562 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 1563 continue; 1564 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 1565 // Special handling for statement expressions. The last statement in 1566 // the statement expression is also a block-level expr. 1567 const CompoundStmt* C = Terminator->getSubStmt(); 1568 if (!C->body_empty()) { 1569 unsigned x = M->size(); 1570 (*M)[C->body_back()] = x; 1571 } 1572 } 1573 1574 unsigned x = M->size(); 1575 (*M)[Exp] = x; 1576 } 1577 1578 // Look at terminators. The condition is a block-level expression. 1579 1580 Stmt* S = (*I)->getTerminatorCondition(); 1581 1582 if (S && M->find(S) == M->end()) { 1583 unsigned x = M->size(); 1584 (*M)[S] = x; 1585 } 1586 } 1587 1588 return M; 1589} 1590 1591CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 1592 assert(S != NULL); 1593 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 1594 1595 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 1596 BlkExprMapTy::iterator I = M->find(S); 1597 1598 if (I == M->end()) return CFG::BlkExprNumTy(); 1599 else return CFG::BlkExprNumTy(I->second); 1600} 1601 1602unsigned CFG::getNumBlkExprs() { 1603 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 1604 return M->size(); 1605 else { 1606 // We assume callers interested in the number of BlkExprs will want 1607 // the map constructed if it doesn't already exist. 1608 BlkExprMap = (void*) PopulateBlkExprMap(*this); 1609 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 1610 } 1611} 1612 1613//===----------------------------------------------------------------------===// 1614// Cleanup: CFG dstor. 1615//===----------------------------------------------------------------------===// 1616 1617CFG::~CFG() { 1618 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 1619} 1620 1621//===----------------------------------------------------------------------===// 1622// CFG pretty printing 1623//===----------------------------------------------------------------------===// 1624 1625namespace { 1626 1627class VISIBILITY_HIDDEN StmtPrinterHelper : public PrinterHelper { 1628 1629 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 1630 StmtMapTy StmtMap; 1631 signed CurrentBlock; 1632 unsigned CurrentStmt; 1633 const LangOptions &LangOpts; 1634public: 1635 1636 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 1637 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 1638 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 1639 unsigned j = 1; 1640 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 1641 BI != BEnd; ++BI, ++j ) 1642 StmtMap[*BI] = std::make_pair((*I)->getBlockID(),j); 1643 } 1644 } 1645 1646 virtual ~StmtPrinterHelper() {} 1647 1648 const LangOptions &getLangOpts() const { return LangOpts; } 1649 void setBlockID(signed i) { CurrentBlock = i; } 1650 void setStmtID(unsigned i) { CurrentStmt = i; } 1651 1652 virtual bool handledStmt(Stmt* Terminator, llvm::raw_ostream& OS) { 1653 1654 StmtMapTy::iterator I = StmtMap.find(Terminator); 1655 1656 if (I == StmtMap.end()) 1657 return false; 1658 1659 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 1660 && I->second.second == CurrentStmt) 1661 return false; 1662 1663 OS << "[B" << I->second.first << "." << I->second.second << "]"; 1664 return true; 1665 } 1666}; 1667} // end anonymous namespace 1668 1669 1670namespace { 1671class VISIBILITY_HIDDEN CFGBlockTerminatorPrint 1672 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 1673 1674 llvm::raw_ostream& OS; 1675 StmtPrinterHelper* Helper; 1676 PrintingPolicy Policy; 1677 1678public: 1679 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 1680 const PrintingPolicy &Policy) 1681 : OS(os), Helper(helper), Policy(Policy) {} 1682 1683 void VisitIfStmt(IfStmt* I) { 1684 OS << "if "; 1685 I->getCond()->printPretty(OS,Helper,Policy); 1686 } 1687 1688 // Default case. 1689 void VisitStmt(Stmt* Terminator) { 1690 Terminator->printPretty(OS, Helper, Policy); 1691 } 1692 1693 void VisitForStmt(ForStmt* F) { 1694 OS << "for (" ; 1695 if (F->getInit()) OS << "..."; 1696 OS << "; "; 1697 if (Stmt* C = F->getCond()) C->printPretty(OS, Helper, Policy); 1698 OS << "; "; 1699 if (F->getInc()) OS << "..."; 1700 OS << ")"; 1701 } 1702 1703 void VisitWhileStmt(WhileStmt* W) { 1704 OS << "while " ; 1705 if (Stmt* C = W->getCond()) C->printPretty(OS, Helper, Policy); 1706 } 1707 1708 void VisitDoStmt(DoStmt* D) { 1709 OS << "do ... while "; 1710 if (Stmt* C = D->getCond()) C->printPretty(OS, Helper, Policy); 1711 } 1712 1713 void VisitSwitchStmt(SwitchStmt* Terminator) { 1714 OS << "switch "; 1715 Terminator->getCond()->printPretty(OS, Helper, Policy); 1716 } 1717 1718 void VisitConditionalOperator(ConditionalOperator* C) { 1719 C->getCond()->printPretty(OS, Helper, Policy); 1720 OS << " ? ... : ..."; 1721 } 1722 1723 void VisitChooseExpr(ChooseExpr* C) { 1724 OS << "__builtin_choose_expr( "; 1725 C->getCond()->printPretty(OS, Helper, Policy); 1726 OS << " )"; 1727 } 1728 1729 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1730 OS << "goto *"; 1731 I->getTarget()->printPretty(OS, Helper, Policy); 1732 } 1733 1734 void VisitBinaryOperator(BinaryOperator* B) { 1735 if (!B->isLogicalOp()) { 1736 VisitExpr(B); 1737 return; 1738 } 1739 1740 B->getLHS()->printPretty(OS, Helper, Policy); 1741 1742 switch (B->getOpcode()) { 1743 case BinaryOperator::LOr: 1744 OS << " || ..."; 1745 return; 1746 case BinaryOperator::LAnd: 1747 OS << " && ..."; 1748 return; 1749 default: 1750 assert(false && "Invalid logical operator."); 1751 } 1752 } 1753 1754 void VisitExpr(Expr* E) { 1755 E->printPretty(OS, Helper, Policy); 1756 } 1757}; 1758} // end anonymous namespace 1759 1760 1761static void print_stmt(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 1762 Stmt* Terminator) { 1763 if (Helper) { 1764 // special printing for statement-expressions. 1765 if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) { 1766 CompoundStmt* Sub = SE->getSubStmt(); 1767 1768 if (Sub->child_begin() != Sub->child_end()) { 1769 OS << "({ ... ; "; 1770 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 1771 OS << " })\n"; 1772 return; 1773 } 1774 } 1775 1776 // special printing for comma expressions. 1777 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) { 1778 if (B->getOpcode() == BinaryOperator::Comma) { 1779 OS << "... , "; 1780 Helper->handledStmt(B->getRHS(),OS); 1781 OS << '\n'; 1782 return; 1783 } 1784 } 1785 } 1786 1787 Terminator->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 1788 1789 // Expressions need a newline. 1790 if (isa<Expr>(Terminator)) OS << '\n'; 1791} 1792 1793static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 1794 const CFGBlock& B, 1795 StmtPrinterHelper* Helper, bool print_edges) { 1796 1797 if (Helper) Helper->setBlockID(B.getBlockID()); 1798 1799 // Print the header. 1800 OS << "\n [ B" << B.getBlockID(); 1801 1802 if (&B == &cfg->getEntry()) 1803 OS << " (ENTRY) ]\n"; 1804 else if (&B == &cfg->getExit()) 1805 OS << " (EXIT) ]\n"; 1806 else if (&B == cfg->getIndirectGotoBlock()) 1807 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 1808 else 1809 OS << " ]\n"; 1810 1811 // Print the label of this block. 1812 if (Stmt* Terminator = const_cast<Stmt*>(B.getLabel())) { 1813 1814 if (print_edges) 1815 OS << " "; 1816 1817 if (LabelStmt* L = dyn_cast<LabelStmt>(Terminator)) 1818 OS << L->getName(); 1819 else if (CaseStmt* C = dyn_cast<CaseStmt>(Terminator)) { 1820 OS << "case "; 1821 C->getLHS()->printPretty(OS, Helper, 1822 PrintingPolicy(Helper->getLangOpts())); 1823 if (C->getRHS()) { 1824 OS << " ... "; 1825 C->getRHS()->printPretty(OS, Helper, 1826 PrintingPolicy(Helper->getLangOpts())); 1827 } 1828 } else if (isa<DefaultStmt>(Terminator)) 1829 OS << "default"; 1830 else 1831 assert(false && "Invalid label statement in CFGBlock."); 1832 1833 OS << ":\n"; 1834 } 1835 1836 // Iterate through the statements in the block and print them. 1837 unsigned j = 1; 1838 1839 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 1840 I != E ; ++I, ++j ) { 1841 1842 // Print the statement # in the basic block and the statement itself. 1843 if (print_edges) 1844 OS << " "; 1845 1846 OS << llvm::format("%3d", j) << ": "; 1847 1848 if (Helper) 1849 Helper->setStmtID(j); 1850 1851 print_stmt(OS,Helper,*I); 1852 } 1853 1854 // Print the terminator of this block. 1855 if (B.getTerminator()) { 1856 if (print_edges) 1857 OS << " "; 1858 1859 OS << " T: "; 1860 1861 if (Helper) Helper->setBlockID(-1); 1862 1863 CFGBlockTerminatorPrint TPrinter(OS, Helper, 1864 PrintingPolicy(Helper->getLangOpts())); 1865 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 1866 OS << '\n'; 1867 } 1868 1869 if (print_edges) { 1870 // Print the predecessors of this block. 1871 OS << " Predecessors (" << B.pred_size() << "):"; 1872 unsigned i = 0; 1873 1874 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 1875 I != E; ++I, ++i) { 1876 1877 if (i == 8 || (i-8) == 0) 1878 OS << "\n "; 1879 1880 OS << " B" << (*I)->getBlockID(); 1881 } 1882 1883 OS << '\n'; 1884 1885 // Print the successors of this block. 1886 OS << " Successors (" << B.succ_size() << "):"; 1887 i = 0; 1888 1889 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 1890 I != E; ++I, ++i) { 1891 1892 if (i == 8 || (i-8) % 10 == 0) 1893 OS << "\n "; 1894 1895 if (*I) 1896 OS << " B" << (*I)->getBlockID(); 1897 else 1898 OS << " NULL"; 1899 } 1900 1901 OS << '\n'; 1902 } 1903} 1904 1905 1906/// dump - A simple pretty printer of a CFG that outputs to stderr. 1907void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 1908 1909/// print - A simple pretty printer of a CFG that outputs to an ostream. 1910void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 1911 StmtPrinterHelper Helper(this, LO); 1912 1913 // Print the entry block. 1914 print_block(OS, this, getEntry(), &Helper, true); 1915 1916 // Iterate through the CFGBlocks and print them one by one. 1917 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 1918 // Skip the entry block, because we already printed it. 1919 if (&(**I) == &getEntry() || &(**I) == &getExit()) 1920 continue; 1921 1922 print_block(OS, this, **I, &Helper, true); 1923 } 1924 1925 // Print the exit block. 1926 print_block(OS, this, getExit(), &Helper, true); 1927 OS.flush(); 1928} 1929 1930/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 1931void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 1932 print(llvm::errs(), cfg, LO); 1933} 1934 1935/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 1936/// Generally this will only be called from CFG::print. 1937void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 1938 const LangOptions &LO) const { 1939 StmtPrinterHelper Helper(cfg, LO); 1940 print_block(OS, cfg, *this, &Helper, true); 1941} 1942 1943/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 1944void CFGBlock::printTerminator(llvm::raw_ostream &OS, 1945 const LangOptions &LO) const { 1946 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 1947 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 1948} 1949 1950Stmt* CFGBlock::getTerminatorCondition() { 1951 1952 if (!Terminator) 1953 return NULL; 1954 1955 Expr* E = NULL; 1956 1957 switch (Terminator->getStmtClass()) { 1958 default: 1959 break; 1960 1961 case Stmt::ForStmtClass: 1962 E = cast<ForStmt>(Terminator)->getCond(); 1963 break; 1964 1965 case Stmt::WhileStmtClass: 1966 E = cast<WhileStmt>(Terminator)->getCond(); 1967 break; 1968 1969 case Stmt::DoStmtClass: 1970 E = cast<DoStmt>(Terminator)->getCond(); 1971 break; 1972 1973 case Stmt::IfStmtClass: 1974 E = cast<IfStmt>(Terminator)->getCond(); 1975 break; 1976 1977 case Stmt::ChooseExprClass: 1978 E = cast<ChooseExpr>(Terminator)->getCond(); 1979 break; 1980 1981 case Stmt::IndirectGotoStmtClass: 1982 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 1983 break; 1984 1985 case Stmt::SwitchStmtClass: 1986 E = cast<SwitchStmt>(Terminator)->getCond(); 1987 break; 1988 1989 case Stmt::ConditionalOperatorClass: 1990 E = cast<ConditionalOperator>(Terminator)->getCond(); 1991 break; 1992 1993 case Stmt::BinaryOperatorClass: // '&&' and '||' 1994 E = cast<BinaryOperator>(Terminator)->getLHS(); 1995 break; 1996 1997 case Stmt::ObjCForCollectionStmtClass: 1998 return Terminator; 1999 } 2000 2001 return E ? E->IgnoreParens() : NULL; 2002} 2003 2004bool CFGBlock::hasBinaryBranchTerminator() const { 2005 2006 if (!Terminator) 2007 return false; 2008 2009 Expr* E = NULL; 2010 2011 switch (Terminator->getStmtClass()) { 2012 default: 2013 return false; 2014 2015 case Stmt::ForStmtClass: 2016 case Stmt::WhileStmtClass: 2017 case Stmt::DoStmtClass: 2018 case Stmt::IfStmtClass: 2019 case Stmt::ChooseExprClass: 2020 case Stmt::ConditionalOperatorClass: 2021 case Stmt::BinaryOperatorClass: 2022 return true; 2023 } 2024 2025 return E ? E->IgnoreParens() : NULL; 2026} 2027 2028 2029//===----------------------------------------------------------------------===// 2030// CFG Graphviz Visualization 2031//===----------------------------------------------------------------------===// 2032 2033 2034#ifndef NDEBUG 2035static StmtPrinterHelper* GraphHelper; 2036#endif 2037 2038void CFG::viewCFG(const LangOptions &LO) const { 2039#ifndef NDEBUG 2040 StmtPrinterHelper H(this, LO); 2041 GraphHelper = &H; 2042 llvm::ViewGraph(this,"CFG"); 2043 GraphHelper = NULL; 2044#endif 2045} 2046 2047namespace llvm { 2048template<> 2049struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2050 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph, 2051 bool ShortNames) { 2052 2053#ifndef NDEBUG 2054 std::string OutSStr; 2055 llvm::raw_string_ostream Out(OutSStr); 2056 print_block(Out,Graph, *Node, GraphHelper, false); 2057 std::string& OutStr = Out.str(); 2058 2059 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2060 2061 // Process string output to make it nicer... 2062 for (unsigned i = 0; i != OutStr.length(); ++i) 2063 if (OutStr[i] == '\n') { // Left justify 2064 OutStr[i] = '\\'; 2065 OutStr.insert(OutStr.begin()+i+1, 'l'); 2066 } 2067 2068 return OutStr; 2069#else 2070 return ""; 2071#endif 2072 } 2073}; 2074} // end namespace llvm 2075