CFG.cpp revision 13fc08a323b29dd97a46def1e3a15bf082476efa
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/CFG.h" 16#include "clang/AST/StmtVisitor.h" 17#include "clang/AST/PrettyPrinter.h" 18#include "llvm/ADT/DenseMap.h" 19#include "llvm/ADT/SmallPtrSet.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Streams.h" 22#include "llvm/Support/Compiler.h" 23#include <llvm/Support/Allocator.h> 24#include <llvm/Support/Format.h> 25 26using namespace clang; 27 28namespace { 29 30// SaveAndRestore - A utility class that uses RIIA to save and restore 31// the value of a variable. 32template<typename T> 33struct VISIBILITY_HIDDEN SaveAndRestore { 34 SaveAndRestore(T& x) : X(x), old_value(x) {} 35 ~SaveAndRestore() { X = old_value; } 36 T get() { return old_value; } 37 38 T& X; 39 T old_value; 40}; 41 42static SourceLocation GetEndLoc(Decl* D) { 43 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 44 if (Expr* Ex = VD->getInit()) 45 return Ex->getSourceRange().getEnd(); 46 47 return D->getLocation(); 48} 49 50/// CFGBuilder - This class implements CFG construction from an AST. 51/// The builder is stateful: an instance of the builder should be used to only 52/// construct a single CFG. 53/// 54/// Example usage: 55/// 56/// CFGBuilder builder; 57/// CFG* cfg = builder.BuildAST(stmt1); 58/// 59/// CFG construction is done via a recursive walk of an AST. We actually parse 60/// the AST in reverse order so that the successor of a basic block is 61/// constructed prior to its predecessor. This allows us to nicely capture 62/// implicit fall-throughs without extra basic blocks. 63/// 64class VISIBILITY_HIDDEN CFGBuilder { 65 CFG* cfg; 66 CFGBlock* Block; 67 CFGBlock* Succ; 68 CFGBlock* ContinueTargetBlock; 69 CFGBlock* BreakTargetBlock; 70 CFGBlock* SwitchTerminatedBlock; 71 CFGBlock* DefaultCaseBlock; 72 73 // LabelMap records the mapping from Label expressions to their blocks. 74 typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy; 75 LabelMapTy LabelMap; 76 77 // A list of blocks that end with a "goto" that must be backpatched to their 78 // resolved targets upon completion of CFG construction. 79 typedef std::vector<CFGBlock*> BackpatchBlocksTy; 80 BackpatchBlocksTy BackpatchBlocks; 81 82 // A list of labels whose address has been taken (for indirect gotos). 83 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 84 LabelSetTy AddressTakenLabels; 85 86public: 87 explicit CFGBuilder() : cfg(NULL), Block(NULL), Succ(NULL), 88 ContinueTargetBlock(NULL), BreakTargetBlock(NULL), 89 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL) { 90 // Create an empty CFG. 91 cfg = new CFG(); 92 } 93 94 ~CFGBuilder() { delete cfg; } 95 96 // buildCFG - Used by external clients to construct the CFG. 97 CFG* buildCFG(Stmt* Statement); 98 99private: 100 // Visitors to walk an AST and construct the CFG. 101 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, bool alwaysAdd); 102 CFGBlock *VisitBinaryOperator(BinaryOperator *B, bool alwaysAdd); 103 CFGBlock *VisitBlockExpr(BlockExpr* E, bool alwaysAdd); 104 CFGBlock *VisitBlockDeclRefExpr(BlockDeclRefExpr* E, bool alwaysAdd); 105 CFGBlock *VisitBreakStmt(BreakStmt *B); 106 CFGBlock *VisitCallExpr(CallExpr *C, bool alwaysAdd); 107 CFGBlock *VisitCaseStmt(CaseStmt *C); 108 CFGBlock *VisitChooseExpr(ChooseExpr *C); 109 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 110 CFGBlock *VisitConditionalOperator(ConditionalOperator *C); 111 CFGBlock *VisitContinueStmt(ContinueStmt *C); 112 CFGBlock *VisitDeclStmt(DeclStmt *DS); 113 CFGBlock *VisitDeclSubExpr(Decl* D); 114 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 115 CFGBlock *VisitDoStmt(DoStmt *D); 116 CFGBlock *VisitForStmt(ForStmt *F); 117 CFGBlock *VisitGotoStmt(GotoStmt* G); 118 CFGBlock *VisitIfStmt(IfStmt *I); 119 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 120 CFGBlock *VisitLabelStmt(LabelStmt *L); 121 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 122 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 123 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 124 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 125 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 126 CFGBlock *VisitReturnStmt(ReturnStmt* R); 127 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, bool alwaysAdd); 128 CFGBlock *VisitStmtExpr(StmtExpr *S, bool alwaysAdd); 129 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 130 CFGBlock *VisitWhileStmt(WhileStmt *W); 131 132 CFGBlock *Visit(Stmt *S, bool alwaysAdd = false); 133 CFGBlock *VisitStmt(Stmt *S, bool alwaysAdd); 134 CFGBlock *VisitChildren(Stmt* S); 135 136 // NYS == Not Yet Supported 137 CFGBlock* NYS() { 138 badCFG = true; 139 return Block; 140 } 141 142 void autoCreateBlock() { if (!Block) Block = createBlock(); } 143 CFGBlock *createBlock(bool add_successor = true); 144 bool FinishBlock(CFGBlock* B); 145 CFGBlock *addStmt(Stmt *S) { return Visit(S, true); } 146 147 bool badCFG; 148}; 149 150// FIXME: Add support for dependent-sized array types in C++? 151// Does it even make sense to build a CFG for an uninstantiated template? 152static VariableArrayType* FindVA(Type* t) { 153 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 154 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 155 if (vat->getSizeExpr()) 156 return vat; 157 158 t = vt->getElementType().getTypePtr(); 159 } 160 161 return 0; 162} 163 164/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 165/// arbitrary statement. Examples include a single expression or a function 166/// body (compound statement). The ownership of the returned CFG is 167/// transferred to the caller. If CFG construction fails, this method returns 168/// NULL. 169CFG* CFGBuilder::buildCFG(Stmt* Statement) { 170 assert(cfg); 171 if (!Statement) 172 return NULL; 173 174 badCFG = false; 175 176 // Create an empty block that will serve as the exit block for the CFG. Since 177 // this is the first block added to the CFG, it will be implicitly registered 178 // as the exit block. 179 Succ = createBlock(); 180 assert (Succ == &cfg->getExit()); 181 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 182 183 // Visit the statements and create the CFG. 184 CFGBlock* B = addStmt(Statement); 185 if (!B) B = Succ; 186 187 if (B) { 188 // Finalize the last constructed block. This usually involves reversing the 189 // order of the statements in the block. 190 if (Block) FinishBlock(B); 191 192 // Backpatch the gotos whose label -> block mappings we didn't know when we 193 // encountered them. 194 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 195 E = BackpatchBlocks.end(); I != E; ++I ) { 196 197 CFGBlock* B = *I; 198 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 199 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 200 201 // If there is no target for the goto, then we are looking at an 202 // incomplete AST. Handle this by not registering a successor. 203 if (LI == LabelMap.end()) continue; 204 205 B->addSuccessor(LI->second); 206 } 207 208 // Add successors to the Indirect Goto Dispatch block (if we have one). 209 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 210 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 211 E = AddressTakenLabels.end(); I != E; ++I ) { 212 213 // Lookup the target block. 214 LabelMapTy::iterator LI = LabelMap.find(*I); 215 216 // If there is no target block that contains label, then we are looking 217 // at an incomplete AST. Handle this by not registering a successor. 218 if (LI == LabelMap.end()) continue; 219 220 B->addSuccessor(LI->second); 221 } 222 223 Succ = B; 224 } 225 226 // Create an empty entry block that has no predecessors. 227 cfg->setEntry(createBlock()); 228 229 if (badCFG) { 230 delete cfg; 231 cfg = NULL; 232 return NULL; 233 } 234 235 // NULL out cfg so that repeated calls to the builder will fail and that the 236 // ownership of the constructed CFG is passed to the caller. 237 CFG* t = cfg; 238 cfg = NULL; 239 return t; 240} 241 242/// createBlock - Used to lazily create blocks that are connected 243/// to the current (global) succcessor. 244CFGBlock* CFGBuilder::createBlock(bool add_successor) { 245 CFGBlock* B = cfg->createBlock(); 246 if (add_successor && Succ) 247 B->addSuccessor(Succ); 248 return B; 249} 250 251/// FinishBlock - When the last statement has been added to the block, we must 252/// reverse the statements because they have been inserted in reverse order. 253bool CFGBuilder::FinishBlock(CFGBlock* B) { 254 if (badCFG) 255 return false; 256 257 assert(B); 258 B->reverseStmts(); 259 return true; 260} 261 262/// Visit - Walk the subtree of a statement and add extra 263/// blocks for ternary operators, &&, and ||. We also process "," and 264/// DeclStmts (which may contain nested control-flow). 265CFGBlock* CFGBuilder::Visit(Stmt * S, bool alwaysAdd) { 266tryAgain: 267 switch (S->getStmtClass()) { 268 default: 269 return VisitStmt(S, alwaysAdd); 270 271 case Stmt::AddrLabelExprClass: 272 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), alwaysAdd); 273 274 case Stmt::BinaryOperatorClass: 275 return VisitBinaryOperator(cast<BinaryOperator>(S), alwaysAdd); 276 277 case Stmt::BlockExprClass: 278 return VisitBlockExpr(cast<BlockExpr>(S), alwaysAdd); 279 280 case Stmt::BlockDeclRefExprClass: 281 return VisitBlockDeclRefExpr(cast<BlockDeclRefExpr>(S), alwaysAdd); 282 283 case Stmt::BreakStmtClass: 284 return VisitBreakStmt(cast<BreakStmt>(S)); 285 286 case Stmt::CallExprClass: 287 return VisitCallExpr(cast<CallExpr>(S), alwaysAdd); 288 289 case Stmt::CaseStmtClass: 290 return VisitCaseStmt(cast<CaseStmt>(S)); 291 292 case Stmt::ChooseExprClass: 293 return VisitChooseExpr(cast<ChooseExpr>(S)); 294 295 case Stmt::CompoundStmtClass: 296 return VisitCompoundStmt(cast<CompoundStmt>(S)); 297 298 case Stmt::ConditionalOperatorClass: 299 return VisitConditionalOperator(cast<ConditionalOperator>(S)); 300 301 case Stmt::ContinueStmtClass: 302 return VisitContinueStmt(cast<ContinueStmt>(S)); 303 304 case Stmt::DeclStmtClass: 305 return VisitDeclStmt(cast<DeclStmt>(S)); 306 307 case Stmt::DefaultStmtClass: 308 return VisitDefaultStmt(cast<DefaultStmt>(S)); 309 310 case Stmt::DoStmtClass: 311 return VisitDoStmt(cast<DoStmt>(S)); 312 313 case Stmt::ForStmtClass: 314 return VisitForStmt(cast<ForStmt>(S)); 315 316 case Stmt::GotoStmtClass: 317 return VisitGotoStmt(cast<GotoStmt>(S)); 318 319 case Stmt::IfStmtClass: 320 return VisitIfStmt(cast<IfStmt>(S)); 321 322 case Stmt::IndirectGotoStmtClass: 323 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 324 325 case Stmt::LabelStmtClass: 326 return VisitLabelStmt(cast<LabelStmt>(S)); 327 328 case Stmt::ObjCAtCatchStmtClass: 329 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 330 331 case Stmt::ObjCAtSynchronizedStmtClass: 332 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 333 334 case Stmt::ObjCAtThrowStmtClass: 335 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 336 337 case Stmt::ObjCAtTryStmtClass: 338 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 339 340 case Stmt::ObjCForCollectionStmtClass: 341 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 342 343 case Stmt::ParenExprClass: 344 S = cast<ParenExpr>(S)->getSubExpr(); 345 goto tryAgain; 346 347 case Stmt::NullStmtClass: 348 return Block; 349 350 case Stmt::ReturnStmtClass: 351 return VisitReturnStmt(cast<ReturnStmt>(S)); 352 353 case Stmt::SizeOfAlignOfExprClass: 354 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), alwaysAdd); 355 356 case Stmt::StmtExprClass: 357 return VisitStmtExpr(cast<StmtExpr>(S), alwaysAdd); 358 359 case Stmt::SwitchStmtClass: 360 return VisitSwitchStmt(cast<SwitchStmt>(S)); 361 362 case Stmt::WhileStmtClass: 363 return VisitWhileStmt(cast<WhileStmt>(S)); 364 } 365} 366 367CFGBlock *CFGBuilder::VisitStmt(Stmt *S, bool alwaysAdd) { 368 if (alwaysAdd) { 369 autoCreateBlock(); 370 Block->appendStmt(S); 371 } 372 373 return VisitChildren(S); 374} 375 376/// VisitChildren - Visit the children of a Stmt. 377CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 378 CFGBlock *B = Block; 379 for (Stmt::child_iterator I = Terminator->child_begin(), 380 E = Terminator->child_end(); I != E; ++I) { 381 if (*I) B = Visit(*I); 382 } 383 return B; 384} 385 386CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, bool alwaysAdd) { 387 AddressTakenLabels.insert(A->getLabel()); 388 389 if (alwaysAdd) { 390 autoCreateBlock(); 391 Block->appendStmt(A); 392 } 393 394 return Block; 395} 396 397CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, bool alwaysAdd) { 398 if (B->isLogicalOp()) { // && or || 399 400 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 401 ConfluenceBlock->appendStmt(B); 402 403 if (!FinishBlock(ConfluenceBlock)) 404 return 0; 405 406 // create the block evaluating the LHS 407 CFGBlock* LHSBlock = createBlock(false); 408 LHSBlock->setTerminator(B); 409 410 // create the block evaluating the RHS 411 Succ = ConfluenceBlock; 412 Block = NULL; 413 CFGBlock* RHSBlock = addStmt(B->getRHS()); 414 if (!FinishBlock(RHSBlock)) 415 return 0; 416 417 // Now link the LHSBlock with RHSBlock. 418 if (B->getOpcode() == BinaryOperator::LOr) { 419 LHSBlock->addSuccessor(ConfluenceBlock); 420 LHSBlock->addSuccessor(RHSBlock); 421 } else { 422 assert (B->getOpcode() == BinaryOperator::LAnd); 423 LHSBlock->addSuccessor(RHSBlock); 424 LHSBlock->addSuccessor(ConfluenceBlock); 425 } 426 427 // Generate the blocks for evaluating the LHS. 428 Block = LHSBlock; 429 return addStmt(B->getLHS()); 430 } 431 else if (B->getOpcode() == BinaryOperator::Comma) { // , 432 autoCreateBlock(); 433 Block->appendStmt(B); 434 addStmt(B->getRHS()); 435 return addStmt(B->getLHS()); 436 } 437 438 return VisitStmt(B, alwaysAdd); 439} 440 441CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr* E, bool alwaysAdd) { 442 // FIXME 443 return NYS(); 444} 445 446CFGBlock *CFGBuilder::VisitBlockDeclRefExpr(BlockDeclRefExpr* E, 447 bool alwaysAdd) { 448 // FIXME 449 return NYS(); 450} 451 452CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 453 // "break" is a control-flow statement. Thus we stop processing the current 454 // block. 455 if (Block && !FinishBlock(Block)) 456 return 0; 457 458 // Now create a new block that ends with the break statement. 459 Block = createBlock(false); 460 Block->setTerminator(B); 461 462 // If there is no target for the break, then we are looking at an incomplete 463 // AST. This means that the CFG cannot be constructed. 464 if (BreakTargetBlock) 465 Block->addSuccessor(BreakTargetBlock); 466 else 467 badCFG = true; 468 469 470 return Block; 471} 472 473CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, bool alwaysAdd) { 474 // If this is a call to a no-return function, this stops the block here. 475 if (FunctionDecl *FD = C->getDirectCallee()) { 476 477 if (!FD->hasAttr<NoReturnAttr>()) 478 return VisitStmt(C, alwaysAdd); 479 480 if (Block && !FinishBlock(Block)) 481 return 0; 482 483 // Create new block with no successor for the remaining pieces. 484 Block = createBlock(false); 485 Block->appendStmt(C); 486 487 // Wire this to the exit block directly. 488 Block->addSuccessor(&cfg->getExit()); 489 490 return VisitChildren(C); 491 } 492 493 return VisitStmt(C, alwaysAdd); 494} 495 496CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C) { 497 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 498 ConfluenceBlock->appendStmt(C); 499 if (!FinishBlock(ConfluenceBlock)) 500 return 0; 501 502 Succ = ConfluenceBlock; 503 Block = NULL; 504 CFGBlock* LHSBlock = addStmt(C->getLHS()); 505 if (!FinishBlock(LHSBlock)) 506 return 0; 507 508 Succ = ConfluenceBlock; 509 Block = NULL; 510 CFGBlock* RHSBlock = addStmt(C->getRHS()); 511 if (!FinishBlock(RHSBlock)) 512 return 0; 513 514 Block = createBlock(false); 515 Block->addSuccessor(LHSBlock); 516 Block->addSuccessor(RHSBlock); 517 Block->setTerminator(C); 518 return addStmt(C->getCond()); 519} 520 521 522CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 523 CFGBlock* LastBlock = Block; 524 525 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 526 I != E; ++I ) { 527 LastBlock = addStmt(*I); 528 } 529 return LastBlock; 530} 531 532CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C) { 533 // Create the confluence block that will "merge" the results of the ternary 534 // expression. 535 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 536 ConfluenceBlock->appendStmt(C); 537 if (!FinishBlock(ConfluenceBlock)) 538 return 0; 539 540 // Create a block for the LHS expression if there is an LHS expression. A 541 // GCC extension allows LHS to be NULL, causing the condition to be the 542 // value that is returned instead. 543 // e.g: x ?: y is shorthand for: x ? x : y; 544 Succ = ConfluenceBlock; 545 Block = NULL; 546 CFGBlock* LHSBlock = NULL; 547 if (C->getLHS()) { 548 LHSBlock = addStmt(C->getLHS()); 549 if (!FinishBlock(LHSBlock)) 550 return 0; 551 Block = NULL; 552 } 553 554 // Create the block for the RHS expression. 555 Succ = ConfluenceBlock; 556 CFGBlock* RHSBlock = addStmt(C->getRHS()); 557 if (!FinishBlock(RHSBlock)) 558 return 0; 559 560 // Create the block that will contain the condition. 561 Block = createBlock(false); 562 563 if (LHSBlock) 564 Block->addSuccessor(LHSBlock); 565 else { 566 // If we have no LHS expression, add the ConfluenceBlock as a direct 567 // successor for the block containing the condition. Moreover, we need to 568 // reverse the order of the predecessors in the ConfluenceBlock because 569 // the RHSBlock will have been added to the succcessors already, and we 570 // want the first predecessor to the the block containing the expression 571 // for the case when the ternary expression evaluates to true. 572 Block->addSuccessor(ConfluenceBlock); 573 assert (ConfluenceBlock->pred_size() == 2); 574 std::reverse(ConfluenceBlock->pred_begin(), 575 ConfluenceBlock->pred_end()); 576 } 577 578 Block->addSuccessor(RHSBlock); 579 580 Block->setTerminator(C); 581 return addStmt(C->getCond()); 582} 583 584CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 585 autoCreateBlock(); 586 587 if (DS->isSingleDecl()) { 588 Block->appendStmt(DS); 589 return VisitDeclSubExpr(DS->getSingleDecl()); 590 } 591 592 CFGBlock *B = 0; 593 594 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 595 typedef llvm::SmallVector<Decl*,10> BufTy; 596 BufTy Buf(DS->decl_begin(), DS->decl_end()); 597 598 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 599 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 600 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 601 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 602 603 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 604 // automatically freed with the CFG. 605 DeclGroupRef DG(*I); 606 Decl *D = *I; 607 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 608 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 609 610 // Append the fake DeclStmt to block. 611 Block->appendStmt(DSNew); 612 B = VisitDeclSubExpr(D); 613 } 614 615 return B; 616} 617 618/// VisitDeclSubExpr - Utility method to add block-level expressions for 619/// initializers in Decls. 620CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 621 assert(Block); 622 623 VarDecl *VD = dyn_cast<VarDecl>(D); 624 625 if (!VD) 626 return Block; 627 628 Expr *Init = VD->getInit(); 629 630 if (Init) { 631 // Optimization: Don't create separate block-level statements for literals. 632 switch (Init->getStmtClass()) { 633 case Stmt::IntegerLiteralClass: 634 case Stmt::CharacterLiteralClass: 635 case Stmt::StringLiteralClass: 636 break; 637 default: 638 Block = addStmt(Init); 639 } 640 } 641 642 // If the type of VD is a VLA, then we must process its size expressions. 643 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 644 VA = FindVA(VA->getElementType().getTypePtr())) 645 Block = addStmt(VA->getSizeExpr()); 646 647 return Block; 648} 649 650CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 651 // We may see an if statement in the middle of a basic block, or it may be the 652 // first statement we are processing. In either case, we create a new basic 653 // block. First, we create the blocks for the then...else statements, and 654 // then we create the block containing the if statement. If we were in the 655 // middle of a block, we stop processing that block and reverse its 656 // statements. That block is then the implicit successor for the "then" and 657 // "else" clauses. 658 659 // The block we were proccessing is now finished. Make it the successor 660 // block. 661 if (Block) { 662 Succ = Block; 663 if (!FinishBlock(Block)) 664 return 0; 665 } 666 667 // Process the false branch. 668 CFGBlock* ElseBlock = Succ; 669 670 if (Stmt* Else = I->getElse()) { 671 SaveAndRestore<CFGBlock*> sv(Succ); 672 673 // NULL out Block so that the recursive call to Visit will 674 // create a new basic block. 675 Block = NULL; 676 ElseBlock = addStmt(Else); 677 678 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 679 ElseBlock = sv.get(); 680 else if (Block) { 681 if (!FinishBlock(ElseBlock)) 682 return 0; 683 } 684 } 685 686 // Process the true branch. 687 CFGBlock* ThenBlock; 688 { 689 Stmt* Then = I->getThen(); 690 assert (Then); 691 SaveAndRestore<CFGBlock*> sv(Succ); 692 Block = NULL; 693 ThenBlock = addStmt(Then); 694 695 if (!ThenBlock) { 696 // We can reach here if the "then" body has all NullStmts. 697 // Create an empty block so we can distinguish between true and false 698 // branches in path-sensitive analyses. 699 ThenBlock = createBlock(false); 700 ThenBlock->addSuccessor(sv.get()); 701 } else if (Block) { 702 if (!FinishBlock(ThenBlock)) 703 return 0; 704 } 705 } 706 707 // Now create a new block containing the if statement. 708 Block = createBlock(false); 709 710 // Set the terminator of the new block to the If statement. 711 Block->setTerminator(I); 712 713 // Now add the successors. 714 Block->addSuccessor(ThenBlock); 715 Block->addSuccessor(ElseBlock); 716 717 // Add the condition as the last statement in the new block. This may create 718 // new blocks as the condition may contain control-flow. Any newly created 719 // blocks will be pointed to be "Block". 720 return addStmt(I->getCond()); 721} 722 723 724CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 725 // If we were in the middle of a block we stop processing that block and 726 // reverse its statements. 727 // 728 // NOTE: If a "return" appears in the middle of a block, this means that the 729 // code afterwards is DEAD (unreachable). We still keep a basic block 730 // for that code; a simple "mark-and-sweep" from the entry block will be 731 // able to report such dead blocks. 732 if (Block) FinishBlock(Block); 733 734 // Create the new block. 735 Block = createBlock(false); 736 737 // The Exit block is the only successor. 738 Block->addSuccessor(&cfg->getExit()); 739 740 // Add the return statement to the block. This may create new blocks if R 741 // contains control-flow (short-circuit operations). 742 return VisitStmt(R, true); 743} 744 745CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 746 // Get the block of the labeled statement. Add it to our map. 747 addStmt(L->getSubStmt()); 748 CFGBlock* LabelBlock = Block; 749 750 if (!LabelBlock) // This can happen when the body is empty, i.e. 751 LabelBlock = createBlock(); // scopes that only contains NullStmts. 752 753 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 754 LabelMap[ L ] = LabelBlock; 755 756 // Labels partition blocks, so this is the end of the basic block we were 757 // processing (L is the block's label). Because this is label (and we have 758 // already processed the substatement) there is no extra control-flow to worry 759 // about. 760 LabelBlock->setLabel(L); 761 if (!FinishBlock(LabelBlock)) 762 return 0; 763 764 // We set Block to NULL to allow lazy creation of a new block (if necessary); 765 Block = NULL; 766 767 // This block is now the implicit successor of other blocks. 768 Succ = LabelBlock; 769 770 return LabelBlock; 771} 772 773CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 774 // Goto is a control-flow statement. Thus we stop processing the current 775 // block and create a new one. 776 if (Block) 777 FinishBlock(Block); 778 779 Block = createBlock(false); 780 Block->setTerminator(G); 781 782 // If we already know the mapping to the label block add the successor now. 783 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 784 785 if (I == LabelMap.end()) 786 // We will need to backpatch this block later. 787 BackpatchBlocks.push_back(Block); 788 else 789 Block->addSuccessor(I->second); 790 791 return Block; 792} 793 794CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 795 // "for" is a control-flow statement. Thus we stop processing the current 796 // block. 797 CFGBlock* LoopSuccessor = NULL; 798 799 if (Block) { 800 if (!FinishBlock(Block)) 801 return 0; 802 LoopSuccessor = Block; 803 } else 804 LoopSuccessor = Succ; 805 806 // Because of short-circuit evaluation, the condition of the loop can span 807 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 808 // evaluate the condition. 809 CFGBlock* ExitConditionBlock = createBlock(false); 810 CFGBlock* EntryConditionBlock = ExitConditionBlock; 811 812 // Set the terminator for the "exit" condition block. 813 ExitConditionBlock->setTerminator(F); 814 815 // Now add the actual condition to the condition block. Because the condition 816 // itself may contain control-flow, new blocks may be created. 817 if (Stmt* C = F->getCond()) { 818 Block = ExitConditionBlock; 819 EntryConditionBlock = addStmt(C); 820 if (Block) { 821 if (!FinishBlock(EntryConditionBlock)) 822 return 0; 823 } 824 } 825 826 // The condition block is the implicit successor for the loop body as well as 827 // any code above the loop. 828 Succ = EntryConditionBlock; 829 830 // Now create the loop body. 831 { 832 assert (F->getBody()); 833 834 // Save the current values for Block, Succ, and continue and break targets 835 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 836 save_continue(ContinueTargetBlock), 837 save_break(BreakTargetBlock); 838 839 // Create a new block to contain the (bottom) of the loop body. 840 Block = NULL; 841 842 if (Stmt* I = F->getInc()) { 843 // Generate increment code in its own basic block. This is the target of 844 // continue statements. 845 Succ = addStmt(I); 846 } else { 847 // No increment code. Create a special, empty, block that is used as the 848 // target block for "looping back" to the start of the loop. 849 assert(Succ == EntryConditionBlock); 850 Succ = createBlock(); 851 } 852 853 // Finish up the increment (or empty) block if it hasn't been already. 854 if (Block) { 855 assert(Block == Succ); 856 if (!FinishBlock(Block)) 857 return 0; 858 Block = 0; 859 } 860 861 ContinueTargetBlock = Succ; 862 863 // The starting block for the loop increment is the block that should 864 // represent the 'loop target' for looping back to the start of the loop. 865 ContinueTargetBlock->setLoopTarget(F); 866 867 // All breaks should go to the code following the loop. 868 BreakTargetBlock = LoopSuccessor; 869 870 // Now populate the body block, and in the process create new blocks as we 871 // walk the body of the loop. 872 CFGBlock* BodyBlock = addStmt(F->getBody()); 873 874 if (!BodyBlock) 875 BodyBlock = EntryConditionBlock; // can happen for "for (...;...; ) ;" 876 else if (Block) { 877 if (!FinishBlock(BodyBlock)) 878 return 0; 879 } 880 881 // This new body block is a successor to our "exit" condition block. 882 ExitConditionBlock->addSuccessor(BodyBlock); 883 } 884 885 // Link up the condition block with the code that follows the loop. (the 886 // false branch). 887 ExitConditionBlock->addSuccessor(LoopSuccessor); 888 889 // If the loop contains initialization, create a new block for those 890 // statements. This block can also contain statements that precede the loop. 891 if (Stmt* I = F->getInit()) { 892 Block = createBlock(); 893 return addStmt(I); 894 } else { 895 // There is no loop initialization. We are thus basically a while loop. 896 // NULL out Block to force lazy block construction. 897 Block = NULL; 898 Succ = EntryConditionBlock; 899 return EntryConditionBlock; 900 } 901} 902 903CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 904 // Objective-C fast enumeration 'for' statements: 905 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 906 // 907 // for ( Type newVariable in collection_expression ) { statements } 908 // 909 // becomes: 910 // 911 // prologue: 912 // 1. collection_expression 913 // T. jump to loop_entry 914 // loop_entry: 915 // 1. side-effects of element expression 916 // 1. ObjCForCollectionStmt [performs binding to newVariable] 917 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 918 // TB: 919 // statements 920 // T. jump to loop_entry 921 // FB: 922 // what comes after 923 // 924 // and 925 // 926 // Type existingItem; 927 // for ( existingItem in expression ) { statements } 928 // 929 // becomes: 930 // 931 // the same with newVariable replaced with existingItem; the binding works 932 // the same except that for one ObjCForCollectionStmt::getElement() returns 933 // a DeclStmt and the other returns a DeclRefExpr. 934 // 935 936 CFGBlock* LoopSuccessor = 0; 937 938 if (Block) { 939 if (!FinishBlock(Block)) 940 return 0; 941 LoopSuccessor = Block; 942 Block = 0; 943 } else 944 LoopSuccessor = Succ; 945 946 // Build the condition blocks. 947 CFGBlock* ExitConditionBlock = createBlock(false); 948 CFGBlock* EntryConditionBlock = ExitConditionBlock; 949 950 // Set the terminator for the "exit" condition block. 951 ExitConditionBlock->setTerminator(S); 952 953 // The last statement in the block should be the ObjCForCollectionStmt, which 954 // performs the actual binding to 'element' and determines if there are any 955 // more items in the collection. 956 ExitConditionBlock->appendStmt(S); 957 Block = ExitConditionBlock; 958 959 // Walk the 'element' expression to see if there are any side-effects. We 960 // generate new blocks as necesary. We DON'T add the statement by default to 961 // the CFG unless it contains control-flow. 962 EntryConditionBlock = Visit(S->getElement(), false); 963 if (Block) { 964 if (!FinishBlock(EntryConditionBlock)) 965 return 0; 966 Block = 0; 967 } 968 969 // The condition block is the implicit successor for the loop body as well as 970 // any code above the loop. 971 Succ = EntryConditionBlock; 972 973 // Now create the true branch. 974 { 975 // Save the current values for Succ, continue and break targets. 976 SaveAndRestore<CFGBlock*> save_Succ(Succ), 977 save_continue(ContinueTargetBlock), save_break(BreakTargetBlock); 978 979 BreakTargetBlock = LoopSuccessor; 980 ContinueTargetBlock = EntryConditionBlock; 981 982 CFGBlock* BodyBlock = addStmt(S->getBody()); 983 984 if (!BodyBlock) 985 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 986 else if (Block) { 987 if (!FinishBlock(BodyBlock)) 988 return 0; 989 } 990 991 // This new body block is a successor to our "exit" condition block. 992 ExitConditionBlock->addSuccessor(BodyBlock); 993 } 994 995 // Link up the condition block with the code that follows the loop. 996 // (the false branch). 997 ExitConditionBlock->addSuccessor(LoopSuccessor); 998 999 // Now create a prologue block to contain the collection expression. 1000 Block = createBlock(); 1001 return addStmt(S->getCollection()); 1002} 1003 1004CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1005 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1006 1007 // Inline the body. 1008 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1009 1010 // The sync body starts its own basic block. This makes it a little easier 1011 // for diagnostic clients. 1012 if (SyncBlock) { 1013 if (!FinishBlock(SyncBlock)) 1014 return 0; 1015 1016 Block = 0; 1017 } 1018 1019 Succ = SyncBlock; 1020 1021 // Inline the sync expression. 1022 return addStmt(S->getSynchExpr()); 1023} 1024 1025CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1026 // FIXME 1027 return NYS(); 1028} 1029 1030CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1031 // "while" is a control-flow statement. Thus we stop processing the current 1032 // block. 1033 1034 CFGBlock* LoopSuccessor = NULL; 1035 1036 if (Block) { 1037 if (!FinishBlock(Block)) 1038 return 0; 1039 LoopSuccessor = Block; 1040 } else 1041 LoopSuccessor = Succ; 1042 1043 // Because of short-circuit evaluation, the condition of the loop can span 1044 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1045 // evaluate the condition. 1046 CFGBlock* ExitConditionBlock = createBlock(false); 1047 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1048 1049 // Set the terminator for the "exit" condition block. 1050 ExitConditionBlock->setTerminator(W); 1051 1052 // Now add the actual condition to the condition block. Because the condition 1053 // itself may contain control-flow, new blocks may be created. Thus we update 1054 // "Succ" after adding the condition. 1055 if (Stmt* C = W->getCond()) { 1056 Block = ExitConditionBlock; 1057 EntryConditionBlock = addStmt(C); 1058 assert(Block == EntryConditionBlock); 1059 if (Block) { 1060 if (!FinishBlock(EntryConditionBlock)) 1061 return 0; 1062 } 1063 } 1064 1065 // The condition block is the implicit successor for the loop body as well as 1066 // any code above the loop. 1067 Succ = EntryConditionBlock; 1068 1069 // Process the loop body. 1070 { 1071 assert(W->getBody()); 1072 1073 // Save the current values for Block, Succ, and continue and break targets 1074 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1075 save_continue(ContinueTargetBlock), 1076 save_break(BreakTargetBlock); 1077 1078 // Create an empty block to represent the transition block for looping back 1079 // to the head of the loop. 1080 Block = 0; 1081 assert(Succ == EntryConditionBlock); 1082 Succ = createBlock(); 1083 Succ->setLoopTarget(W); 1084 ContinueTargetBlock = Succ; 1085 1086 // All breaks should go to the code following the loop. 1087 BreakTargetBlock = LoopSuccessor; 1088 1089 // NULL out Block to force lazy instantiation of blocks for the body. 1090 Block = NULL; 1091 1092 // Create the body. The returned block is the entry to the loop body. 1093 CFGBlock* BodyBlock = addStmt(W->getBody()); 1094 1095 if (!BodyBlock) 1096 BodyBlock = EntryConditionBlock; // can happen for "while(...) ;" 1097 else if (Block) { 1098 if (!FinishBlock(BodyBlock)) 1099 return 0; 1100 } 1101 1102 // Add the loop body entry as a successor to the condition. 1103 ExitConditionBlock->addSuccessor(BodyBlock); 1104 } 1105 1106 // Link up the condition block with the code that follows the loop. (the 1107 // false branch). 1108 ExitConditionBlock->addSuccessor(LoopSuccessor); 1109 1110 // There can be no more statements in the condition block since we loop back 1111 // to this block. NULL out Block to force lazy creation of another block. 1112 Block = NULL; 1113 1114 // Return the condition block, which is the dominating block for the loop. 1115 Succ = EntryConditionBlock; 1116 return EntryConditionBlock; 1117} 1118 1119 1120CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1121 // FIXME: For now we pretend that @catch and the code it contains does not 1122 // exit. 1123 return Block; 1124} 1125 1126CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1127 // FIXME: This isn't complete. We basically treat @throw like a return 1128 // statement. 1129 1130 // If we were in the middle of a block we stop processing that block and 1131 // reverse its statements. 1132 if (Block && !FinishBlock(Block)) 1133 return 0; 1134 1135 // Create the new block. 1136 Block = createBlock(false); 1137 1138 // The Exit block is the only successor. 1139 Block->addSuccessor(&cfg->getExit()); 1140 1141 // Add the statement to the block. This may create new blocks if S contains 1142 // control-flow (short-circuit operations). 1143 return VisitStmt(S, true); 1144} 1145 1146CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1147 // "do...while" is a control-flow statement. Thus we stop processing the 1148 // current block. 1149 1150 CFGBlock* LoopSuccessor = NULL; 1151 1152 if (Block) { 1153 if (!FinishBlock(Block)) 1154 return 0; 1155 LoopSuccessor = Block; 1156 } else 1157 LoopSuccessor = Succ; 1158 1159 // Because of short-circuit evaluation, the condition of the loop can span 1160 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1161 // evaluate the condition. 1162 CFGBlock* ExitConditionBlock = createBlock(false); 1163 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1164 1165 // Set the terminator for the "exit" condition block. 1166 ExitConditionBlock->setTerminator(D); 1167 1168 // Now add the actual condition to the condition block. Because the condition 1169 // itself may contain control-flow, new blocks may be created. 1170 if (Stmt* C = D->getCond()) { 1171 Block = ExitConditionBlock; 1172 EntryConditionBlock = addStmt(C); 1173 if (Block) { 1174 if (!FinishBlock(EntryConditionBlock)) 1175 return 0; 1176 } 1177 } 1178 1179 // The condition block is the implicit successor for the loop body. 1180 Succ = EntryConditionBlock; 1181 1182 // Process the loop body. 1183 CFGBlock* BodyBlock = NULL; 1184 { 1185 assert (D->getBody()); 1186 1187 // Save the current values for Block, Succ, and continue and break targets 1188 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1189 save_continue(ContinueTargetBlock), 1190 save_break(BreakTargetBlock); 1191 1192 // All continues within this loop should go to the condition block 1193 ContinueTargetBlock = EntryConditionBlock; 1194 1195 // All breaks should go to the code following the loop. 1196 BreakTargetBlock = LoopSuccessor; 1197 1198 // NULL out Block to force lazy instantiation of blocks for the body. 1199 Block = NULL; 1200 1201 // Create the body. The returned block is the entry to the loop body. 1202 BodyBlock = addStmt(D->getBody()); 1203 1204 if (!BodyBlock) 1205 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1206 else if (Block) { 1207 if (!FinishBlock(BodyBlock)) 1208 return 0; 1209 } 1210 1211 // Add an intermediate block between the BodyBlock and the 1212 // ExitConditionBlock to represent the "loop back" transition. Create an 1213 // empty block to represent the transition block for looping back to the 1214 // head of the loop. 1215 // FIXME: Can we do this more efficiently without adding another block? 1216 Block = NULL; 1217 Succ = BodyBlock; 1218 CFGBlock *LoopBackBlock = createBlock(); 1219 LoopBackBlock->setLoopTarget(D); 1220 1221 // Add the loop body entry as a successor to the condition. 1222 ExitConditionBlock->addSuccessor(LoopBackBlock); 1223 } 1224 1225 // Link up the condition block with the code that follows the loop. 1226 // (the false branch). 1227 ExitConditionBlock->addSuccessor(LoopSuccessor); 1228 1229 // There can be no more statements in the body block(s) since we loop back to 1230 // the body. NULL out Block to force lazy creation of another block. 1231 Block = NULL; 1232 1233 // Return the loop body, which is the dominating block for the loop. 1234 Succ = BodyBlock; 1235 return BodyBlock; 1236} 1237 1238CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1239 // "continue" is a control-flow statement. Thus we stop processing the 1240 // current block. 1241 if (Block && !FinishBlock(Block)) 1242 return 0; 1243 1244 // Now create a new block that ends with the continue statement. 1245 Block = createBlock(false); 1246 Block->setTerminator(C); 1247 1248 // If there is no target for the continue, then we are looking at an 1249 // incomplete AST. This means the CFG cannot be constructed. 1250 if (ContinueTargetBlock) 1251 Block->addSuccessor(ContinueTargetBlock); 1252 else 1253 badCFG = true; 1254 1255 return Block; 1256} 1257 1258CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1259 bool alwaysAdd) { 1260 1261 if (alwaysAdd) { 1262 autoCreateBlock(); 1263 Block->appendStmt(E); 1264 } 1265 1266 // VLA types have expressions that must be evaluated. 1267 if (E->isArgumentType()) { 1268 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1269 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1270 addStmt(VA->getSizeExpr()); 1271 } 1272 1273 return Block; 1274} 1275 1276/// VisitStmtExpr - Utility method to handle (nested) statement 1277/// expressions (a GCC extension). 1278CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, bool alwaysAdd) { 1279 if (alwaysAdd) { 1280 autoCreateBlock(); 1281 Block->appendStmt(SE); 1282 } 1283 return VisitCompoundStmt(SE->getSubStmt()); 1284} 1285 1286CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1287 // "switch" is a control-flow statement. Thus we stop processing the current 1288 // block. 1289 CFGBlock* SwitchSuccessor = NULL; 1290 1291 if (Block) { 1292 if (!FinishBlock(Block)) 1293 return 0; 1294 SwitchSuccessor = Block; 1295 } else SwitchSuccessor = Succ; 1296 1297 // Save the current "switch" context. 1298 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1299 save_break(BreakTargetBlock), 1300 save_default(DefaultCaseBlock); 1301 1302 // Set the "default" case to be the block after the switch statement. If the 1303 // switch statement contains a "default:", this value will be overwritten with 1304 // the block for that code. 1305 DefaultCaseBlock = SwitchSuccessor; 1306 1307 // Create a new block that will contain the switch statement. 1308 SwitchTerminatedBlock = createBlock(false); 1309 1310 // Now process the switch body. The code after the switch is the implicit 1311 // successor. 1312 Succ = SwitchSuccessor; 1313 BreakTargetBlock = SwitchSuccessor; 1314 1315 // When visiting the body, the case statements should automatically get linked 1316 // up to the switch. We also don't keep a pointer to the body, since all 1317 // control-flow from the switch goes to case/default statements. 1318 assert (Terminator->getBody() && "switch must contain a non-NULL body"); 1319 Block = NULL; 1320 CFGBlock *BodyBlock = addStmt(Terminator->getBody()); 1321 if (Block) { 1322 if (!FinishBlock(BodyBlock)) 1323 return 0; 1324 } 1325 1326 // If we have no "default:" case, the default transition is to the code 1327 // following the switch body. 1328 SwitchTerminatedBlock->addSuccessor(DefaultCaseBlock); 1329 1330 // Add the terminator and condition in the switch block. 1331 SwitchTerminatedBlock->setTerminator(Terminator); 1332 assert (Terminator->getCond() && "switch condition must be non-NULL"); 1333 Block = SwitchTerminatedBlock; 1334 1335 return addStmt(Terminator->getCond()); 1336} 1337 1338CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1339 // CaseStmts are essentially labels, so they are the first statement in a 1340 // block. 1341 1342 if (CS->getSubStmt()) 1343 addStmt(CS->getSubStmt()); 1344 1345 CFGBlock* CaseBlock = Block; 1346 if (!CaseBlock) 1347 CaseBlock = createBlock(); 1348 1349 // Cases statements partition blocks, so this is the top of the basic block we 1350 // were processing (the "case XXX:" is the label). 1351 CaseBlock->setLabel(CS); 1352 1353 if (!FinishBlock(CaseBlock)) 1354 return 0; 1355 1356 // Add this block to the list of successors for the block with the switch 1357 // statement. 1358 assert(SwitchTerminatedBlock); 1359 SwitchTerminatedBlock->addSuccessor(CaseBlock); 1360 1361 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1362 Block = NULL; 1363 1364 // This block is now the implicit successor of other blocks. 1365 Succ = CaseBlock; 1366 1367 return CaseBlock; 1368} 1369 1370CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 1371 if (Terminator->getSubStmt()) 1372 addStmt(Terminator->getSubStmt()); 1373 1374 DefaultCaseBlock = Block; 1375 1376 if (!DefaultCaseBlock) 1377 DefaultCaseBlock = createBlock(); 1378 1379 // Default statements partition blocks, so this is the top of the basic block 1380 // we were processing (the "default:" is the label). 1381 DefaultCaseBlock->setLabel(Terminator); 1382 1383 if (!FinishBlock(DefaultCaseBlock)) 1384 return 0; 1385 1386 // Unlike case statements, we don't add the default block to the successors 1387 // for the switch statement immediately. This is done when we finish 1388 // processing the switch statement. This allows for the default case 1389 // (including a fall-through to the code after the switch statement) to always 1390 // be the last successor of a switch-terminated block. 1391 1392 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1393 Block = NULL; 1394 1395 // This block is now the implicit successor of other blocks. 1396 Succ = DefaultCaseBlock; 1397 1398 return DefaultCaseBlock; 1399} 1400 1401CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1402 // Lazily create the indirect-goto dispatch block if there isn't one already. 1403 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 1404 1405 if (!IBlock) { 1406 IBlock = createBlock(false); 1407 cfg->setIndirectGotoBlock(IBlock); 1408 } 1409 1410 // IndirectGoto is a control-flow statement. Thus we stop processing the 1411 // current block and create a new one. 1412 if (Block && !FinishBlock(Block)) 1413 return 0; 1414 1415 Block = createBlock(false); 1416 Block->setTerminator(I); 1417 Block->addSuccessor(IBlock); 1418 return addStmt(I->getTarget()); 1419} 1420 1421} // end anonymous namespace 1422 1423/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 1424/// no successors or predecessors. If this is the first block created in the 1425/// CFG, it is automatically set to be the Entry and Exit of the CFG. 1426CFGBlock* CFG::createBlock() { 1427 bool first_block = begin() == end(); 1428 1429 // Create the block. 1430 Blocks.push_front(CFGBlock(NumBlockIDs++)); 1431 1432 // If this is the first block, set it as the Entry and Exit. 1433 if (first_block) Entry = Exit = &front(); 1434 1435 // Return the block. 1436 return &front(); 1437} 1438 1439/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 1440/// CFG is returned to the caller. 1441CFG* CFG::buildCFG(Stmt* Statement) { 1442 CFGBuilder Builder; 1443 return Builder.buildCFG(Statement); 1444} 1445 1446/// reverseStmts - Reverses the orders of statements within a CFGBlock. 1447void CFGBlock::reverseStmts() { std::reverse(Stmts.begin(),Stmts.end()); } 1448 1449//===----------------------------------------------------------------------===// 1450// CFG: Queries for BlkExprs. 1451//===----------------------------------------------------------------------===// 1452 1453namespace { 1454 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 1455} 1456 1457static void FindSubExprAssignments(Stmt* Terminator, llvm::SmallPtrSet<Expr*,50>& Set) { 1458 if (!Terminator) 1459 return; 1460 1461 for (Stmt::child_iterator I=Terminator->child_begin(), E=Terminator->child_end(); I!=E; ++I) { 1462 if (!*I) continue; 1463 1464 if (BinaryOperator* B = dyn_cast<BinaryOperator>(*I)) 1465 if (B->isAssignmentOp()) Set.insert(B); 1466 1467 FindSubExprAssignments(*I, Set); 1468 } 1469} 1470 1471static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 1472 BlkExprMapTy* M = new BlkExprMapTy(); 1473 1474 // Look for assignments that are used as subexpressions. These are the only 1475 // assignments that we want to *possibly* register as a block-level 1476 // expression. Basically, if an assignment occurs both in a subexpression and 1477 // at the block-level, it is a block-level expression. 1478 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 1479 1480 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 1481 for (CFGBlock::iterator BI=I->begin(), EI=I->end(); BI != EI; ++BI) 1482 FindSubExprAssignments(*BI, SubExprAssignments); 1483 1484 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 1485 1486 // Iterate over the statements again on identify the Expr* and Stmt* at the 1487 // block-level that are block-level expressions. 1488 1489 for (CFGBlock::iterator BI=I->begin(), EI=I->end(); BI != EI; ++BI) 1490 if (Expr* Exp = dyn_cast<Expr>(*BI)) { 1491 1492 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 1493 // Assignment expressions that are not nested within another 1494 // expression are really "statements" whose value is never used by 1495 // another expression. 1496 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 1497 continue; 1498 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 1499 // Special handling for statement expressions. The last statement in 1500 // the statement expression is also a block-level expr. 1501 const CompoundStmt* C = Terminator->getSubStmt(); 1502 if (!C->body_empty()) { 1503 unsigned x = M->size(); 1504 (*M)[C->body_back()] = x; 1505 } 1506 } 1507 1508 unsigned x = M->size(); 1509 (*M)[Exp] = x; 1510 } 1511 1512 // Look at terminators. The condition is a block-level expression. 1513 1514 Stmt* S = I->getTerminatorCondition(); 1515 1516 if (S && M->find(S) == M->end()) { 1517 unsigned x = M->size(); 1518 (*M)[S] = x; 1519 } 1520 } 1521 1522 return M; 1523} 1524 1525CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 1526 assert(S != NULL); 1527 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 1528 1529 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 1530 BlkExprMapTy::iterator I = M->find(S); 1531 1532 if (I == M->end()) return CFG::BlkExprNumTy(); 1533 else return CFG::BlkExprNumTy(I->second); 1534} 1535 1536unsigned CFG::getNumBlkExprs() { 1537 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 1538 return M->size(); 1539 else { 1540 // We assume callers interested in the number of BlkExprs will want 1541 // the map constructed if it doesn't already exist. 1542 BlkExprMap = (void*) PopulateBlkExprMap(*this); 1543 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 1544 } 1545} 1546 1547//===----------------------------------------------------------------------===// 1548// Cleanup: CFG dstor. 1549//===----------------------------------------------------------------------===// 1550 1551CFG::~CFG() { 1552 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 1553} 1554 1555//===----------------------------------------------------------------------===// 1556// CFG pretty printing 1557//===----------------------------------------------------------------------===// 1558 1559namespace { 1560 1561class VISIBILITY_HIDDEN StmtPrinterHelper : public PrinterHelper { 1562 1563 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 1564 StmtMapTy StmtMap; 1565 signed CurrentBlock; 1566 unsigned CurrentStmt; 1567 const LangOptions &LangOpts; 1568public: 1569 1570 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 1571 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 1572 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 1573 unsigned j = 1; 1574 for (CFGBlock::const_iterator BI = I->begin(), BEnd = I->end() ; 1575 BI != BEnd; ++BI, ++j ) 1576 StmtMap[*BI] = std::make_pair(I->getBlockID(),j); 1577 } 1578 } 1579 1580 virtual ~StmtPrinterHelper() {} 1581 1582 const LangOptions &getLangOpts() const { return LangOpts; } 1583 void setBlockID(signed i) { CurrentBlock = i; } 1584 void setStmtID(unsigned i) { CurrentStmt = i; } 1585 1586 virtual bool handledStmt(Stmt* Terminator, llvm::raw_ostream& OS) { 1587 1588 StmtMapTy::iterator I = StmtMap.find(Terminator); 1589 1590 if (I == StmtMap.end()) 1591 return false; 1592 1593 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 1594 && I->second.second == CurrentStmt) 1595 return false; 1596 1597 OS << "[B" << I->second.first << "." << I->second.second << "]"; 1598 return true; 1599 } 1600}; 1601} // end anonymous namespace 1602 1603 1604namespace { 1605class VISIBILITY_HIDDEN CFGBlockTerminatorPrint 1606 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 1607 1608 llvm::raw_ostream& OS; 1609 StmtPrinterHelper* Helper; 1610 PrintingPolicy Policy; 1611 1612public: 1613 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 1614 const PrintingPolicy &Policy) 1615 : OS(os), Helper(helper), Policy(Policy) {} 1616 1617 void VisitIfStmt(IfStmt* I) { 1618 OS << "if "; 1619 I->getCond()->printPretty(OS,Helper,Policy); 1620 } 1621 1622 // Default case. 1623 void VisitStmt(Stmt* Terminator) { 1624 Terminator->printPretty(OS, Helper, Policy); 1625 } 1626 1627 void VisitForStmt(ForStmt* F) { 1628 OS << "for (" ; 1629 if (F->getInit()) OS << "..."; 1630 OS << "; "; 1631 if (Stmt* C = F->getCond()) C->printPretty(OS, Helper, Policy); 1632 OS << "; "; 1633 if (F->getInc()) OS << "..."; 1634 OS << ")"; 1635 } 1636 1637 void VisitWhileStmt(WhileStmt* W) { 1638 OS << "while " ; 1639 if (Stmt* C = W->getCond()) C->printPretty(OS, Helper, Policy); 1640 } 1641 1642 void VisitDoStmt(DoStmt* D) { 1643 OS << "do ... while "; 1644 if (Stmt* C = D->getCond()) C->printPretty(OS, Helper, Policy); 1645 } 1646 1647 void VisitSwitchStmt(SwitchStmt* Terminator) { 1648 OS << "switch "; 1649 Terminator->getCond()->printPretty(OS, Helper, Policy); 1650 } 1651 1652 void VisitConditionalOperator(ConditionalOperator* C) { 1653 C->getCond()->printPretty(OS, Helper, Policy); 1654 OS << " ? ... : ..."; 1655 } 1656 1657 void VisitChooseExpr(ChooseExpr* C) { 1658 OS << "__builtin_choose_expr( "; 1659 C->getCond()->printPretty(OS, Helper, Policy); 1660 OS << " )"; 1661 } 1662 1663 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1664 OS << "goto *"; 1665 I->getTarget()->printPretty(OS, Helper, Policy); 1666 } 1667 1668 void VisitBinaryOperator(BinaryOperator* B) { 1669 if (!B->isLogicalOp()) { 1670 VisitExpr(B); 1671 return; 1672 } 1673 1674 B->getLHS()->printPretty(OS, Helper, Policy); 1675 1676 switch (B->getOpcode()) { 1677 case BinaryOperator::LOr: 1678 OS << " || ..."; 1679 return; 1680 case BinaryOperator::LAnd: 1681 OS << " && ..."; 1682 return; 1683 default: 1684 assert(false && "Invalid logical operator."); 1685 } 1686 } 1687 1688 void VisitExpr(Expr* E) { 1689 E->printPretty(OS, Helper, Policy); 1690 } 1691}; 1692} // end anonymous namespace 1693 1694 1695static void print_stmt(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 1696 Stmt* Terminator) { 1697 if (Helper) { 1698 // special printing for statement-expressions. 1699 if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) { 1700 CompoundStmt* Sub = SE->getSubStmt(); 1701 1702 if (Sub->child_begin() != Sub->child_end()) { 1703 OS << "({ ... ; "; 1704 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 1705 OS << " })\n"; 1706 return; 1707 } 1708 } 1709 1710 // special printing for comma expressions. 1711 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) { 1712 if (B->getOpcode() == BinaryOperator::Comma) { 1713 OS << "... , "; 1714 Helper->handledStmt(B->getRHS(),OS); 1715 OS << '\n'; 1716 return; 1717 } 1718 } 1719 } 1720 1721 Terminator->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 1722 1723 // Expressions need a newline. 1724 if (isa<Expr>(Terminator)) OS << '\n'; 1725} 1726 1727static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 1728 const CFGBlock& B, 1729 StmtPrinterHelper* Helper, bool print_edges) { 1730 1731 if (Helper) Helper->setBlockID(B.getBlockID()); 1732 1733 // Print the header. 1734 OS << "\n [ B" << B.getBlockID(); 1735 1736 if (&B == &cfg->getEntry()) 1737 OS << " (ENTRY) ]\n"; 1738 else if (&B == &cfg->getExit()) 1739 OS << " (EXIT) ]\n"; 1740 else if (&B == cfg->getIndirectGotoBlock()) 1741 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 1742 else 1743 OS << " ]\n"; 1744 1745 // Print the label of this block. 1746 if (Stmt* Terminator = const_cast<Stmt*>(B.getLabel())) { 1747 1748 if (print_edges) 1749 OS << " "; 1750 1751 if (LabelStmt* L = dyn_cast<LabelStmt>(Terminator)) 1752 OS << L->getName(); 1753 else if (CaseStmt* C = dyn_cast<CaseStmt>(Terminator)) { 1754 OS << "case "; 1755 C->getLHS()->printPretty(OS, Helper, 1756 PrintingPolicy(Helper->getLangOpts())); 1757 if (C->getRHS()) { 1758 OS << " ... "; 1759 C->getRHS()->printPretty(OS, Helper, 1760 PrintingPolicy(Helper->getLangOpts())); 1761 } 1762 } else if (isa<DefaultStmt>(Terminator)) 1763 OS << "default"; 1764 else 1765 assert(false && "Invalid label statement in CFGBlock."); 1766 1767 OS << ":\n"; 1768 } 1769 1770 // Iterate through the statements in the block and print them. 1771 unsigned j = 1; 1772 1773 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 1774 I != E ; ++I, ++j ) { 1775 1776 // Print the statement # in the basic block and the statement itself. 1777 if (print_edges) 1778 OS << " "; 1779 1780 OS << llvm::format("%3d", j) << ": "; 1781 1782 if (Helper) 1783 Helper->setStmtID(j); 1784 1785 print_stmt(OS,Helper,*I); 1786 } 1787 1788 // Print the terminator of this block. 1789 if (B.getTerminator()) { 1790 if (print_edges) 1791 OS << " "; 1792 1793 OS << " T: "; 1794 1795 if (Helper) Helper->setBlockID(-1); 1796 1797 CFGBlockTerminatorPrint TPrinter(OS, Helper, 1798 PrintingPolicy(Helper->getLangOpts())); 1799 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 1800 OS << '\n'; 1801 } 1802 1803 if (print_edges) { 1804 // Print the predecessors of this block. 1805 OS << " Predecessors (" << B.pred_size() << "):"; 1806 unsigned i = 0; 1807 1808 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 1809 I != E; ++I, ++i) { 1810 1811 if (i == 8 || (i-8) == 0) 1812 OS << "\n "; 1813 1814 OS << " B" << (*I)->getBlockID(); 1815 } 1816 1817 OS << '\n'; 1818 1819 // Print the successors of this block. 1820 OS << " Successors (" << B.succ_size() << "):"; 1821 i = 0; 1822 1823 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 1824 I != E; ++I, ++i) { 1825 1826 if (i == 8 || (i-8) % 10 == 0) 1827 OS << "\n "; 1828 1829 OS << " B" << (*I)->getBlockID(); 1830 } 1831 1832 OS << '\n'; 1833 } 1834} 1835 1836 1837/// dump - A simple pretty printer of a CFG that outputs to stderr. 1838void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 1839 1840/// print - A simple pretty printer of a CFG that outputs to an ostream. 1841void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 1842 StmtPrinterHelper Helper(this, LO); 1843 1844 // Print the entry block. 1845 print_block(OS, this, getEntry(), &Helper, true); 1846 1847 // Iterate through the CFGBlocks and print them one by one. 1848 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 1849 // Skip the entry block, because we already printed it. 1850 if (&(*I) == &getEntry() || &(*I) == &getExit()) 1851 continue; 1852 1853 print_block(OS, this, *I, &Helper, true); 1854 } 1855 1856 // Print the exit block. 1857 print_block(OS, this, getExit(), &Helper, true); 1858 OS.flush(); 1859} 1860 1861/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 1862void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 1863 print(llvm::errs(), cfg, LO); 1864} 1865 1866/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 1867/// Generally this will only be called from CFG::print. 1868void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 1869 const LangOptions &LO) const { 1870 StmtPrinterHelper Helper(cfg, LO); 1871 print_block(OS, cfg, *this, &Helper, true); 1872} 1873 1874/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 1875void CFGBlock::printTerminator(llvm::raw_ostream &OS, 1876 const LangOptions &LO) const { 1877 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 1878 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 1879} 1880 1881Stmt* CFGBlock::getTerminatorCondition() { 1882 1883 if (!Terminator) 1884 return NULL; 1885 1886 Expr* E = NULL; 1887 1888 switch (Terminator->getStmtClass()) { 1889 default: 1890 break; 1891 1892 case Stmt::ForStmtClass: 1893 E = cast<ForStmt>(Terminator)->getCond(); 1894 break; 1895 1896 case Stmt::WhileStmtClass: 1897 E = cast<WhileStmt>(Terminator)->getCond(); 1898 break; 1899 1900 case Stmt::DoStmtClass: 1901 E = cast<DoStmt>(Terminator)->getCond(); 1902 break; 1903 1904 case Stmt::IfStmtClass: 1905 E = cast<IfStmt>(Terminator)->getCond(); 1906 break; 1907 1908 case Stmt::ChooseExprClass: 1909 E = cast<ChooseExpr>(Terminator)->getCond(); 1910 break; 1911 1912 case Stmt::IndirectGotoStmtClass: 1913 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 1914 break; 1915 1916 case Stmt::SwitchStmtClass: 1917 E = cast<SwitchStmt>(Terminator)->getCond(); 1918 break; 1919 1920 case Stmt::ConditionalOperatorClass: 1921 E = cast<ConditionalOperator>(Terminator)->getCond(); 1922 break; 1923 1924 case Stmt::BinaryOperatorClass: // '&&' and '||' 1925 E = cast<BinaryOperator>(Terminator)->getLHS(); 1926 break; 1927 1928 case Stmt::ObjCForCollectionStmtClass: 1929 return Terminator; 1930 } 1931 1932 return E ? E->IgnoreParens() : NULL; 1933} 1934 1935bool CFGBlock::hasBinaryBranchTerminator() const { 1936 1937 if (!Terminator) 1938 return false; 1939 1940 Expr* E = NULL; 1941 1942 switch (Terminator->getStmtClass()) { 1943 default: 1944 return false; 1945 1946 case Stmt::ForStmtClass: 1947 case Stmt::WhileStmtClass: 1948 case Stmt::DoStmtClass: 1949 case Stmt::IfStmtClass: 1950 case Stmt::ChooseExprClass: 1951 case Stmt::ConditionalOperatorClass: 1952 case Stmt::BinaryOperatorClass: 1953 return true; 1954 } 1955 1956 return E ? E->IgnoreParens() : NULL; 1957} 1958 1959 1960//===----------------------------------------------------------------------===// 1961// CFG Graphviz Visualization 1962//===----------------------------------------------------------------------===// 1963 1964 1965#ifndef NDEBUG 1966static StmtPrinterHelper* GraphHelper; 1967#endif 1968 1969void CFG::viewCFG(const LangOptions &LO) const { 1970#ifndef NDEBUG 1971 StmtPrinterHelper H(this, LO); 1972 GraphHelper = &H; 1973 llvm::ViewGraph(this,"CFG"); 1974 GraphHelper = NULL; 1975#endif 1976} 1977 1978namespace llvm { 1979template<> 1980struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 1981 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph, 1982 bool ShortNames) { 1983 1984#ifndef NDEBUG 1985 std::string OutSStr; 1986 llvm::raw_string_ostream Out(OutSStr); 1987 print_block(Out,Graph, *Node, GraphHelper, false); 1988 std::string& OutStr = Out.str(); 1989 1990 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 1991 1992 // Process string output to make it nicer... 1993 for (unsigned i = 0; i != OutStr.length(); ++i) 1994 if (OutStr[i] == '\n') { // Left justify 1995 OutStr[i] = '\\'; 1996 OutStr.insert(OutStr.begin()+i+1, 'l'); 1997 } 1998 1999 return OutStr; 2000#else 2001 return ""; 2002#endif 2003 } 2004}; 2005} // end namespace llvm 2006