CFG.cpp revision 6f3bb9626d55a2649f7dd1c472589832eb04599e
1//===--- CFG.cpp - Classes for representing and building CFGs----*- C++ -*-===// 2// 3// The LLVM Compiler Infrastructure 4// 5// This file is distributed under the University of Illinois Open Source 6// License. See LICENSE.TXT for details. 7// 8//===----------------------------------------------------------------------===// 9// 10// This file defines the CFG and CFGBuilder classes for representing and 11// building Control-Flow Graphs (CFGs) from ASTs. 12// 13//===----------------------------------------------------------------------===// 14 15#include "clang/Analysis/Support/SaveAndRestore.h" 16#include "clang/Analysis/CFG.h" 17#include "clang/AST/DeclCXX.h" 18#include "clang/AST/StmtVisitor.h" 19#include "clang/AST/PrettyPrinter.h" 20#include "llvm/Support/GraphWriter.h" 21#include "llvm/Support/Allocator.h" 22#include "llvm/Support/Format.h" 23#include "llvm/ADT/DenseMap.h" 24#include "llvm/ADT/SmallPtrSet.h" 25#include "llvm/ADT/OwningPtr.h" 26 27using namespace clang; 28 29namespace { 30 31static SourceLocation GetEndLoc(Decl* D) { 32 if (VarDecl* VD = dyn_cast<VarDecl>(D)) 33 if (Expr* Ex = VD->getInit()) 34 return Ex->getSourceRange().getEnd(); 35 36 return D->getLocation(); 37} 38 39class AddStmtChoice { 40public: 41 enum Kind { NotAlwaysAdd = 0, 42 AlwaysAdd = 1, 43 AsLValueNotAlwaysAdd = 2, 44 AlwaysAddAsLValue = 3 }; 45 46 AddStmtChoice(Kind kind) : k(kind) {} 47 48 bool alwaysAdd() const { return (unsigned)k & 0x1; } 49 bool asLValue() const { return k >= AsLValueNotAlwaysAdd; } 50 51private: 52 Kind k; 53}; 54 55/// CFGBuilder - This class implements CFG construction from an AST. 56/// The builder is stateful: an instance of the builder should be used to only 57/// construct a single CFG. 58/// 59/// Example usage: 60/// 61/// CFGBuilder builder; 62/// CFG* cfg = builder.BuildAST(stmt1); 63/// 64/// CFG construction is done via a recursive walk of an AST. We actually parse 65/// the AST in reverse order so that the successor of a basic block is 66/// constructed prior to its predecessor. This allows us to nicely capture 67/// implicit fall-throughs without extra basic blocks. 68/// 69class CFGBuilder { 70 ASTContext *Context; 71 llvm::OwningPtr<CFG> cfg; 72 73 CFGBlock* Block; 74 CFGBlock* Succ; 75 CFGBlock* ContinueTargetBlock; 76 CFGBlock* BreakTargetBlock; 77 CFGBlock* SwitchTerminatedBlock; 78 CFGBlock* DefaultCaseBlock; 79 CFGBlock* TryTerminatedBlock; 80 81 // LabelMap records the mapping from Label expressions to their blocks. 82 typedef llvm::DenseMap<LabelStmt*,CFGBlock*> LabelMapTy; 83 LabelMapTy LabelMap; 84 85 // A list of blocks that end with a "goto" that must be backpatched to their 86 // resolved targets upon completion of CFG construction. 87 typedef std::vector<CFGBlock*> BackpatchBlocksTy; 88 BackpatchBlocksTy BackpatchBlocks; 89 90 // A list of labels whose address has been taken (for indirect gotos). 91 typedef llvm::SmallPtrSet<LabelStmt*,5> LabelSetTy; 92 LabelSetTy AddressTakenLabels; 93 94public: 95 explicit CFGBuilder() : cfg(new CFG()), // crew a new CFG 96 Block(NULL), Succ(NULL), 97 ContinueTargetBlock(NULL), BreakTargetBlock(NULL), 98 SwitchTerminatedBlock(NULL), DefaultCaseBlock(NULL), 99 TryTerminatedBlock(NULL) {} 100 101 // buildCFG - Used by external clients to construct the CFG. 102 CFG* buildCFG(const Decl *D, Stmt *Statement, ASTContext *C, bool AddEHEdges, 103 bool AddScopes); 104 105private: 106 // Visitors to walk an AST and construct the CFG. 107 CFGBlock *VisitAddrLabelExpr(AddrLabelExpr *A, AddStmtChoice asc); 108 CFGBlock *VisitBinaryOperator(BinaryOperator *B, AddStmtChoice asc); 109 CFGBlock *VisitBlockExpr(BlockExpr* E, AddStmtChoice asc); 110 CFGBlock *VisitBreakStmt(BreakStmt *B); 111 CFGBlock *VisitCXXCatchStmt(CXXCatchStmt *S); 112 CFGBlock *VisitCXXThrowExpr(CXXThrowExpr *T); 113 CFGBlock *VisitCXXTryStmt(CXXTryStmt *S); 114 CFGBlock *VisitCXXMemberCallExpr(CXXMemberCallExpr *C, AddStmtChoice asc); 115 CFGBlock *VisitCallExpr(CallExpr *C, AddStmtChoice asc); 116 CFGBlock *VisitCaseStmt(CaseStmt *C); 117 CFGBlock *VisitChooseExpr(ChooseExpr *C, AddStmtChoice asc); 118 CFGBlock *VisitCompoundStmt(CompoundStmt *C); 119 CFGBlock *VisitConditionalOperator(ConditionalOperator *C, AddStmtChoice asc); 120 CFGBlock *VisitContinueStmt(ContinueStmt *C); 121 CFGBlock *VisitDeclStmt(DeclStmt *DS); 122 CFGBlock *VisitDeclSubExpr(Decl* D); 123 CFGBlock *VisitDefaultStmt(DefaultStmt *D); 124 CFGBlock *VisitDoStmt(DoStmt *D); 125 CFGBlock *VisitForStmt(ForStmt *F); 126 CFGBlock *VisitGotoStmt(GotoStmt* G); 127 CFGBlock *VisitIfStmt(IfStmt *I); 128 CFGBlock *VisitIndirectGotoStmt(IndirectGotoStmt *I); 129 CFGBlock *VisitLabelStmt(LabelStmt *L); 130 CFGBlock *VisitMemberExpr(MemberExpr *M, AddStmtChoice asc); 131 CFGBlock *VisitObjCAtCatchStmt(ObjCAtCatchStmt *S); 132 CFGBlock *VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt *S); 133 CFGBlock *VisitObjCAtThrowStmt(ObjCAtThrowStmt *S); 134 CFGBlock *VisitObjCAtTryStmt(ObjCAtTryStmt *S); 135 CFGBlock *VisitObjCForCollectionStmt(ObjCForCollectionStmt *S); 136 CFGBlock *VisitReturnStmt(ReturnStmt* R); 137 CFGBlock *VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, AddStmtChoice asc); 138 CFGBlock *VisitStmtExpr(StmtExpr *S, AddStmtChoice asc); 139 CFGBlock *VisitSwitchStmt(SwitchStmt *S); 140 CFGBlock *VisitWhileStmt(WhileStmt *W); 141 142 CFGBlock *Visit(Stmt *S, AddStmtChoice asc = AddStmtChoice::NotAlwaysAdd); 143 CFGBlock *VisitStmt(Stmt *S, AddStmtChoice asc); 144 CFGBlock *VisitChildren(Stmt* S); 145 146 // NYS == Not Yet Supported 147 CFGBlock* NYS() { 148 badCFG = true; 149 return Block; 150 } 151 152 CFGBlock *StartScope(Stmt *S, CFGBlock *B) { 153 if (!AddScopes) 154 return B; 155 156 if (B == 0) 157 B = createBlock(); 158 B->StartScope(S, cfg->getBumpVectorContext()); 159 return B; 160 } 161 162 void EndScope(Stmt *S) { 163 if (!AddScopes) 164 return; 165 166 if (Block == 0) 167 Block = createBlock(); 168 Block->EndScope(S, cfg->getBumpVectorContext()); 169 } 170 171 void autoCreateBlock() { if (!Block) Block = createBlock(); } 172 CFGBlock *createBlock(bool add_successor = true); 173 bool FinishBlock(CFGBlock* B); 174 CFGBlock *addStmt(Stmt *S, AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 175 return Visit(S, asc); 176 } 177 178 void AppendStmt(CFGBlock *B, Stmt *S, 179 AddStmtChoice asc = AddStmtChoice::AlwaysAdd) { 180 B->appendStmt(S, cfg->getBumpVectorContext(), asc.asLValue()); 181 } 182 183 void AddSuccessor(CFGBlock *B, CFGBlock *S) { 184 B->addSuccessor(S, cfg->getBumpVectorContext()); 185 } 186 187 /// TryResult - a class representing a variant over the values 188 /// 'true', 'false', or 'unknown'. This is returned by TryEvaluateBool, 189 /// and is used by the CFGBuilder to decide if a branch condition 190 /// can be decided up front during CFG construction. 191 class TryResult { 192 int X; 193 public: 194 TryResult(bool b) : X(b ? 1 : 0) {} 195 TryResult() : X(-1) {} 196 197 bool isTrue() const { return X == 1; } 198 bool isFalse() const { return X == 0; } 199 bool isKnown() const { return X >= 0; } 200 void negate() { 201 assert(isKnown()); 202 X ^= 0x1; 203 } 204 }; 205 206 /// TryEvaluateBool - Try and evaluate the Stmt and return 0 or 1 207 /// if we can evaluate to a known value, otherwise return -1. 208 TryResult TryEvaluateBool(Expr *S) { 209 Expr::EvalResult Result; 210 if (!S->isTypeDependent() && !S->isValueDependent() && 211 S->Evaluate(Result, *Context) && Result.Val.isInt()) 212 return Result.Val.getInt().getBoolValue(); 213 214 return TryResult(); 215 } 216 217 bool badCFG; 218 219 // True iff EH edges on CallExprs should be added to the CFG. 220 bool AddEHEdges; 221 222 // True iff scope start and scope end notes should be added to the CFG. 223 bool AddScopes; 224}; 225 226// FIXME: Add support for dependent-sized array types in C++? 227// Does it even make sense to build a CFG for an uninstantiated template? 228static VariableArrayType* FindVA(Type* t) { 229 while (ArrayType* vt = dyn_cast<ArrayType>(t)) { 230 if (VariableArrayType* vat = dyn_cast<VariableArrayType>(vt)) 231 if (vat->getSizeExpr()) 232 return vat; 233 234 t = vt->getElementType().getTypePtr(); 235 } 236 237 return 0; 238} 239 240/// BuildCFG - Constructs a CFG from an AST (a Stmt*). The AST can represent an 241/// arbitrary statement. Examples include a single expression or a function 242/// body (compound statement). The ownership of the returned CFG is 243/// transferred to the caller. If CFG construction fails, this method returns 244/// NULL. 245CFG* CFGBuilder::buildCFG(const Decl *D, Stmt* Statement, ASTContext* C, 246 bool addehedges, bool AddScopes) { 247 AddEHEdges = addehedges; 248 Context = C; 249 assert(cfg.get()); 250 if (!Statement) 251 return NULL; 252 253 this->AddScopes = AddScopes; 254 badCFG = false; 255 256 // Create an empty block that will serve as the exit block for the CFG. Since 257 // this is the first block added to the CFG, it will be implicitly registered 258 // as the exit block. 259 Succ = createBlock(); 260 assert(Succ == &cfg->getExit()); 261 Block = NULL; // the EXIT block is empty. Create all other blocks lazily. 262 263 // Visit the statements and create the CFG. 264 CFGBlock* B = addStmt(Statement); 265 266 if (const CXXConstructorDecl *CD = dyn_cast_or_null<CXXConstructorDecl>(D)) { 267 // FIXME: Add code for base initializers and member initializers. 268 (void)CD; 269 } 270 if (!B) 271 B = Succ; 272 273 if (B) { 274 // Finalize the last constructed block. This usually involves reversing the 275 // order of the statements in the block. 276 if (Block) FinishBlock(B); 277 278 // Backpatch the gotos whose label -> block mappings we didn't know when we 279 // encountered them. 280 for (BackpatchBlocksTy::iterator I = BackpatchBlocks.begin(), 281 E = BackpatchBlocks.end(); I != E; ++I ) { 282 283 CFGBlock* B = *I; 284 GotoStmt* G = cast<GotoStmt>(B->getTerminator()); 285 LabelMapTy::iterator LI = LabelMap.find(G->getLabel()); 286 287 // If there is no target for the goto, then we are looking at an 288 // incomplete AST. Handle this by not registering a successor. 289 if (LI == LabelMap.end()) continue; 290 291 AddSuccessor(B, LI->second); 292 } 293 294 // Add successors to the Indirect Goto Dispatch block (if we have one). 295 if (CFGBlock* B = cfg->getIndirectGotoBlock()) 296 for (LabelSetTy::iterator I = AddressTakenLabels.begin(), 297 E = AddressTakenLabels.end(); I != E; ++I ) { 298 299 // Lookup the target block. 300 LabelMapTy::iterator LI = LabelMap.find(*I); 301 302 // If there is no target block that contains label, then we are looking 303 // at an incomplete AST. Handle this by not registering a successor. 304 if (LI == LabelMap.end()) continue; 305 306 AddSuccessor(B, LI->second); 307 } 308 309 Succ = B; 310 } 311 312 // Create an empty entry block that has no predecessors. 313 cfg->setEntry(createBlock()); 314 315 return badCFG ? NULL : cfg.take(); 316} 317 318/// createBlock - Used to lazily create blocks that are connected 319/// to the current (global) succcessor. 320CFGBlock* CFGBuilder::createBlock(bool add_successor) { 321 CFGBlock* B = cfg->createBlock(); 322 if (add_successor && Succ) 323 AddSuccessor(B, Succ); 324 return B; 325} 326 327/// FinishBlock - "Finalize" the block by checking if we have a bad CFG. 328bool CFGBuilder::FinishBlock(CFGBlock* B) { 329 if (badCFG) 330 return false; 331 332 assert(B); 333 return true; 334} 335 336/// Visit - Walk the subtree of a statement and add extra 337/// blocks for ternary operators, &&, and ||. We also process "," and 338/// DeclStmts (which may contain nested control-flow). 339CFGBlock* CFGBuilder::Visit(Stmt * S, AddStmtChoice asc) { 340tryAgain: 341 if (!S) { 342 badCFG = true; 343 return 0; 344 } 345 switch (S->getStmtClass()) { 346 default: 347 return VisitStmt(S, asc); 348 349 case Stmt::AddrLabelExprClass: 350 return VisitAddrLabelExpr(cast<AddrLabelExpr>(S), asc); 351 352 case Stmt::BinaryOperatorClass: 353 return VisitBinaryOperator(cast<BinaryOperator>(S), asc); 354 355 case Stmt::BlockExprClass: 356 return VisitBlockExpr(cast<BlockExpr>(S), asc); 357 358 case Stmt::BreakStmtClass: 359 return VisitBreakStmt(cast<BreakStmt>(S)); 360 361 case Stmt::CallExprClass: 362 return VisitCallExpr(cast<CallExpr>(S), asc); 363 364 case Stmt::CaseStmtClass: 365 return VisitCaseStmt(cast<CaseStmt>(S)); 366 367 case Stmt::ChooseExprClass: 368 return VisitChooseExpr(cast<ChooseExpr>(S), asc); 369 370 case Stmt::CompoundStmtClass: 371 return VisitCompoundStmt(cast<CompoundStmt>(S)); 372 373 case Stmt::ConditionalOperatorClass: 374 return VisitConditionalOperator(cast<ConditionalOperator>(S), asc); 375 376 case Stmt::ContinueStmtClass: 377 return VisitContinueStmt(cast<ContinueStmt>(S)); 378 379 case Stmt::CXXCatchStmtClass: 380 return VisitCXXCatchStmt(cast<CXXCatchStmt>(S)); 381 382 case Stmt::CXXMemberCallExprClass: 383 return VisitCXXMemberCallExpr(cast<CXXMemberCallExpr>(S), asc); 384 385 case Stmt::CXXThrowExprClass: 386 return VisitCXXThrowExpr(cast<CXXThrowExpr>(S)); 387 388 case Stmt::CXXTryStmtClass: 389 return VisitCXXTryStmt(cast<CXXTryStmt>(S)); 390 391 case Stmt::DeclStmtClass: 392 return VisitDeclStmt(cast<DeclStmt>(S)); 393 394 case Stmt::DefaultStmtClass: 395 return VisitDefaultStmt(cast<DefaultStmt>(S)); 396 397 case Stmt::DoStmtClass: 398 return VisitDoStmt(cast<DoStmt>(S)); 399 400 case Stmt::ForStmtClass: 401 return VisitForStmt(cast<ForStmt>(S)); 402 403 case Stmt::GotoStmtClass: 404 return VisitGotoStmt(cast<GotoStmt>(S)); 405 406 case Stmt::IfStmtClass: 407 return VisitIfStmt(cast<IfStmt>(S)); 408 409 case Stmt::IndirectGotoStmtClass: 410 return VisitIndirectGotoStmt(cast<IndirectGotoStmt>(S)); 411 412 case Stmt::LabelStmtClass: 413 return VisitLabelStmt(cast<LabelStmt>(S)); 414 415 case Stmt::MemberExprClass: 416 return VisitMemberExpr(cast<MemberExpr>(S), asc); 417 418 case Stmt::ObjCAtCatchStmtClass: 419 return VisitObjCAtCatchStmt(cast<ObjCAtCatchStmt>(S)); 420 421 case Stmt::ObjCAtSynchronizedStmtClass: 422 return VisitObjCAtSynchronizedStmt(cast<ObjCAtSynchronizedStmt>(S)); 423 424 case Stmt::ObjCAtThrowStmtClass: 425 return VisitObjCAtThrowStmt(cast<ObjCAtThrowStmt>(S)); 426 427 case Stmt::ObjCAtTryStmtClass: 428 return VisitObjCAtTryStmt(cast<ObjCAtTryStmt>(S)); 429 430 case Stmt::ObjCForCollectionStmtClass: 431 return VisitObjCForCollectionStmt(cast<ObjCForCollectionStmt>(S)); 432 433 case Stmt::ParenExprClass: 434 S = cast<ParenExpr>(S)->getSubExpr(); 435 goto tryAgain; 436 437 case Stmt::NullStmtClass: 438 return Block; 439 440 case Stmt::ReturnStmtClass: 441 return VisitReturnStmt(cast<ReturnStmt>(S)); 442 443 case Stmt::SizeOfAlignOfExprClass: 444 return VisitSizeOfAlignOfExpr(cast<SizeOfAlignOfExpr>(S), asc); 445 446 case Stmt::StmtExprClass: 447 return VisitStmtExpr(cast<StmtExpr>(S), asc); 448 449 case Stmt::SwitchStmtClass: 450 return VisitSwitchStmt(cast<SwitchStmt>(S)); 451 452 case Stmt::WhileStmtClass: 453 return VisitWhileStmt(cast<WhileStmt>(S)); 454 } 455} 456 457CFGBlock *CFGBuilder::VisitStmt(Stmt *S, AddStmtChoice asc) { 458 if (asc.alwaysAdd()) { 459 autoCreateBlock(); 460 AppendStmt(Block, S, asc); 461 } 462 463 return VisitChildren(S); 464} 465 466/// VisitChildren - Visit the children of a Stmt. 467CFGBlock *CFGBuilder::VisitChildren(Stmt* Terminator) { 468 CFGBlock *B = Block; 469 for (Stmt::child_iterator I = Terminator->child_begin(), 470 E = Terminator->child_end(); I != E; ++I) { 471 if (*I) B = Visit(*I); 472 } 473 return B; 474} 475 476CFGBlock *CFGBuilder::VisitAddrLabelExpr(AddrLabelExpr *A, 477 AddStmtChoice asc) { 478 AddressTakenLabels.insert(A->getLabel()); 479 480 if (asc.alwaysAdd()) { 481 autoCreateBlock(); 482 AppendStmt(Block, A, asc); 483 } 484 485 return Block; 486} 487 488CFGBlock *CFGBuilder::VisitBinaryOperator(BinaryOperator *B, 489 AddStmtChoice asc) { 490 if (B->isLogicalOp()) { // && or || 491 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 492 AppendStmt(ConfluenceBlock, B, asc); 493 494 if (!FinishBlock(ConfluenceBlock)) 495 return 0; 496 497 // create the block evaluating the LHS 498 CFGBlock* LHSBlock = createBlock(false); 499 LHSBlock->setTerminator(B); 500 501 // create the block evaluating the RHS 502 Succ = ConfluenceBlock; 503 Block = NULL; 504 CFGBlock* RHSBlock = addStmt(B->getRHS()); 505 506 if (RHSBlock) { 507 if (!FinishBlock(RHSBlock)) 508 return 0; 509 } 510 else { 511 // Create an empty block for cases where the RHS doesn't require 512 // any explicit statements in the CFG. 513 RHSBlock = createBlock(); 514 } 515 516 // See if this is a known constant. 517 TryResult KnownVal = TryEvaluateBool(B->getLHS()); 518 if (KnownVal.isKnown() && (B->getOpcode() == BinaryOperator::LOr)) 519 KnownVal.negate(); 520 521 // Now link the LHSBlock with RHSBlock. 522 if (B->getOpcode() == BinaryOperator::LOr) { 523 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 524 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 525 } else { 526 assert(B->getOpcode() == BinaryOperator::LAnd); 527 AddSuccessor(LHSBlock, KnownVal.isFalse() ? NULL : RHSBlock); 528 AddSuccessor(LHSBlock, KnownVal.isTrue() ? NULL : ConfluenceBlock); 529 } 530 531 // Generate the blocks for evaluating the LHS. 532 Block = LHSBlock; 533 return addStmt(B->getLHS()); 534 } 535 else if (B->getOpcode() == BinaryOperator::Comma) { // , 536 autoCreateBlock(); 537 AppendStmt(Block, B, asc); 538 addStmt(B->getRHS()); 539 return addStmt(B->getLHS()); 540 } 541 542 return VisitStmt(B, asc); 543} 544 545CFGBlock *CFGBuilder::VisitBlockExpr(BlockExpr *E, AddStmtChoice asc) { 546 if (asc.alwaysAdd()) { 547 autoCreateBlock(); 548 AppendStmt(Block, E, asc); 549 } 550 return Block; 551} 552 553CFGBlock *CFGBuilder::VisitBreakStmt(BreakStmt *B) { 554 // "break" is a control-flow statement. Thus we stop processing the current 555 // block. 556 if (Block && !FinishBlock(Block)) 557 return 0; 558 559 // Now create a new block that ends with the break statement. 560 Block = createBlock(false); 561 Block->setTerminator(B); 562 563 // If there is no target for the break, then we are looking at an incomplete 564 // AST. This means that the CFG cannot be constructed. 565 if (BreakTargetBlock) 566 AddSuccessor(Block, BreakTargetBlock); 567 else 568 badCFG = true; 569 570 571 return Block; 572} 573 574static bool CanThrow(Expr *E) { 575 QualType Ty = E->getType(); 576 if (Ty->isFunctionPointerType()) 577 Ty = Ty->getAs<PointerType>()->getPointeeType(); 578 else if (Ty->isBlockPointerType()) 579 Ty = Ty->getAs<BlockPointerType>()->getPointeeType(); 580 581 const FunctionType *FT = Ty->getAs<FunctionType>(); 582 if (FT) { 583 if (const FunctionProtoType *Proto = dyn_cast<FunctionProtoType>(FT)) 584 if (Proto->hasEmptyExceptionSpec()) 585 return false; 586 } 587 return true; 588} 589 590CFGBlock *CFGBuilder::VisitCallExpr(CallExpr *C, AddStmtChoice asc) { 591 // If this is a call to a no-return function, this stops the block here. 592 bool NoReturn = false; 593 if (getFunctionExtInfo(*C->getCallee()->getType()).getNoReturn()) { 594 NoReturn = true; 595 } 596 597 bool AddEHEdge = false; 598 599 // Languages without exceptions are assumed to not throw. 600 if (Context->getLangOptions().Exceptions) { 601 if (AddEHEdges) 602 AddEHEdge = true; 603 } 604 605 if (FunctionDecl *FD = C->getDirectCallee()) { 606 if (FD->hasAttr<NoReturnAttr>()) 607 NoReturn = true; 608 if (FD->hasAttr<NoThrowAttr>()) 609 AddEHEdge = false; 610 } 611 612 if (!CanThrow(C->getCallee())) 613 AddEHEdge = false; 614 615 if (!NoReturn && !AddEHEdge) 616 return VisitStmt(C, AddStmtChoice::AlwaysAdd); 617 618 if (Block) { 619 Succ = Block; 620 if (!FinishBlock(Block)) 621 return 0; 622 } 623 624 Block = createBlock(!NoReturn); 625 AppendStmt(Block, C, asc); 626 627 if (NoReturn) { 628 // Wire this to the exit block directly. 629 AddSuccessor(Block, &cfg->getExit()); 630 } 631 if (AddEHEdge) { 632 // Add exceptional edges. 633 if (TryTerminatedBlock) 634 AddSuccessor(Block, TryTerminatedBlock); 635 else 636 AddSuccessor(Block, &cfg->getExit()); 637 } 638 639 return VisitChildren(C); 640} 641 642CFGBlock *CFGBuilder::VisitChooseExpr(ChooseExpr *C, 643 AddStmtChoice asc) { 644 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 645 AppendStmt(ConfluenceBlock, C, asc); 646 if (!FinishBlock(ConfluenceBlock)) 647 return 0; 648 649 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 650 : AddStmtChoice::AlwaysAdd; 651 652 Succ = ConfluenceBlock; 653 Block = NULL; 654 CFGBlock* LHSBlock = addStmt(C->getLHS(), asc); 655 if (!FinishBlock(LHSBlock)) 656 return 0; 657 658 Succ = ConfluenceBlock; 659 Block = NULL; 660 CFGBlock* RHSBlock = addStmt(C->getRHS(), asc); 661 if (!FinishBlock(RHSBlock)) 662 return 0; 663 664 Block = createBlock(false); 665 // See if this is a known constant. 666 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 667 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 668 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 669 Block->setTerminator(C); 670 return addStmt(C->getCond()); 671} 672 673 674CFGBlock* CFGBuilder::VisitCompoundStmt(CompoundStmt* C) { 675 EndScope(C); 676 677 CFGBlock* LastBlock = Block; 678 679 for (CompoundStmt::reverse_body_iterator I=C->body_rbegin(), E=C->body_rend(); 680 I != E; ++I ) { 681 LastBlock = addStmt(*I); 682 683 if (badCFG) 684 return NULL; 685 } 686 687 LastBlock = StartScope(C, LastBlock); 688 689 return LastBlock; 690} 691 692CFGBlock *CFGBuilder::VisitConditionalOperator(ConditionalOperator *C, 693 AddStmtChoice asc) { 694 // Create the confluence block that will "merge" the results of the ternary 695 // expression. 696 CFGBlock* ConfluenceBlock = Block ? Block : createBlock(); 697 AppendStmt(ConfluenceBlock, C, asc); 698 if (!FinishBlock(ConfluenceBlock)) 699 return 0; 700 701 asc = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 702 : AddStmtChoice::AlwaysAdd; 703 704 // Create a block for the LHS expression if there is an LHS expression. A 705 // GCC extension allows LHS to be NULL, causing the condition to be the 706 // value that is returned instead. 707 // e.g: x ?: y is shorthand for: x ? x : y; 708 Succ = ConfluenceBlock; 709 Block = NULL; 710 CFGBlock* LHSBlock = NULL; 711 if (C->getLHS()) { 712 LHSBlock = addStmt(C->getLHS(), asc); 713 if (!FinishBlock(LHSBlock)) 714 return 0; 715 Block = NULL; 716 } 717 718 // Create the block for the RHS expression. 719 Succ = ConfluenceBlock; 720 CFGBlock* RHSBlock = addStmt(C->getRHS(), asc); 721 if (!FinishBlock(RHSBlock)) 722 return 0; 723 724 // Create the block that will contain the condition. 725 Block = createBlock(false); 726 727 // See if this is a known constant. 728 const TryResult& KnownVal = TryEvaluateBool(C->getCond()); 729 if (LHSBlock) { 730 AddSuccessor(Block, KnownVal.isFalse() ? NULL : LHSBlock); 731 } else { 732 if (KnownVal.isFalse()) { 733 // If we know the condition is false, add NULL as the successor for 734 // the block containing the condition. In this case, the confluence 735 // block will have just one predecessor. 736 AddSuccessor(Block, 0); 737 assert(ConfluenceBlock->pred_size() == 1); 738 } else { 739 // If we have no LHS expression, add the ConfluenceBlock as a direct 740 // successor for the block containing the condition. Moreover, we need to 741 // reverse the order of the predecessors in the ConfluenceBlock because 742 // the RHSBlock will have been added to the succcessors already, and we 743 // want the first predecessor to the the block containing the expression 744 // for the case when the ternary expression evaluates to true. 745 AddSuccessor(Block, ConfluenceBlock); 746 assert(ConfluenceBlock->pred_size() == 2); 747 std::reverse(ConfluenceBlock->pred_begin(), 748 ConfluenceBlock->pred_end()); 749 } 750 } 751 752 AddSuccessor(Block, KnownVal.isTrue() ? NULL : RHSBlock); 753 Block->setTerminator(C); 754 return addStmt(C->getCond()); 755} 756 757CFGBlock *CFGBuilder::VisitDeclStmt(DeclStmt *DS) { 758 autoCreateBlock(); 759 760 if (DS->isSingleDecl()) { 761 AppendStmt(Block, DS); 762 return VisitDeclSubExpr(DS->getSingleDecl()); 763 } 764 765 CFGBlock *B = 0; 766 767 // FIXME: Add a reverse iterator for DeclStmt to avoid this extra copy. 768 typedef llvm::SmallVector<Decl*,10> BufTy; 769 BufTy Buf(DS->decl_begin(), DS->decl_end()); 770 771 for (BufTy::reverse_iterator I = Buf.rbegin(), E = Buf.rend(); I != E; ++I) { 772 // Get the alignment of the new DeclStmt, padding out to >=8 bytes. 773 unsigned A = llvm::AlignOf<DeclStmt>::Alignment < 8 774 ? 8 : llvm::AlignOf<DeclStmt>::Alignment; 775 776 // Allocate the DeclStmt using the BumpPtrAllocator. It will get 777 // automatically freed with the CFG. 778 DeclGroupRef DG(*I); 779 Decl *D = *I; 780 void *Mem = cfg->getAllocator().Allocate(sizeof(DeclStmt), A); 781 DeclStmt *DSNew = new (Mem) DeclStmt(DG, D->getLocation(), GetEndLoc(D)); 782 783 // Append the fake DeclStmt to block. 784 AppendStmt(Block, DSNew); 785 B = VisitDeclSubExpr(D); 786 } 787 788 return B; 789} 790 791/// VisitDeclSubExpr - Utility method to add block-level expressions for 792/// initializers in Decls. 793CFGBlock *CFGBuilder::VisitDeclSubExpr(Decl* D) { 794 assert(Block); 795 796 VarDecl *VD = dyn_cast<VarDecl>(D); 797 798 if (!VD) 799 return Block; 800 801 Expr *Init = VD->getInit(); 802 803 if (Init) { 804 AddStmtChoice::Kind k = 805 VD->getType()->isReferenceType() ? AddStmtChoice::AsLValueNotAlwaysAdd 806 : AddStmtChoice::NotAlwaysAdd; 807 Visit(Init, AddStmtChoice(k)); 808 } 809 810 // If the type of VD is a VLA, then we must process its size expressions. 811 for (VariableArrayType* VA = FindVA(VD->getType().getTypePtr()); VA != 0; 812 VA = FindVA(VA->getElementType().getTypePtr())) 813 Block = addStmt(VA->getSizeExpr()); 814 815 return Block; 816} 817 818CFGBlock* CFGBuilder::VisitIfStmt(IfStmt* I) { 819 // We may see an if statement in the middle of a basic block, or it may be the 820 // first statement we are processing. In either case, we create a new basic 821 // block. First, we create the blocks for the then...else statements, and 822 // then we create the block containing the if statement. If we were in the 823 // middle of a block, we stop processing that block. That block is then the 824 // implicit successor for the "then" and "else" clauses. 825 826 // The block we were proccessing is now finished. Make it the successor 827 // block. 828 if (Block) { 829 Succ = Block; 830 if (!FinishBlock(Block)) 831 return 0; 832 } 833 834 // Process the false branch. 835 CFGBlock* ElseBlock = Succ; 836 837 if (Stmt* Else = I->getElse()) { 838 SaveAndRestore<CFGBlock*> sv(Succ); 839 840 // NULL out Block so that the recursive call to Visit will 841 // create a new basic block. 842 Block = NULL; 843 ElseBlock = addStmt(Else); 844 845 if (!ElseBlock) // Can occur when the Else body has all NullStmts. 846 ElseBlock = sv.get(); 847 else if (Block) { 848 if (!FinishBlock(ElseBlock)) 849 return 0; 850 } 851 } 852 853 // Process the true branch. 854 CFGBlock* ThenBlock; 855 { 856 Stmt* Then = I->getThen(); 857 assert(Then); 858 SaveAndRestore<CFGBlock*> sv(Succ); 859 Block = NULL; 860 ThenBlock = addStmt(Then); 861 862 if (!ThenBlock) { 863 // We can reach here if the "then" body has all NullStmts. 864 // Create an empty block so we can distinguish between true and false 865 // branches in path-sensitive analyses. 866 ThenBlock = createBlock(false); 867 AddSuccessor(ThenBlock, sv.get()); 868 } else if (Block) { 869 if (!FinishBlock(ThenBlock)) 870 return 0; 871 } 872 } 873 874 // Now create a new block containing the if statement. 875 Block = createBlock(false); 876 877 // Set the terminator of the new block to the If statement. 878 Block->setTerminator(I); 879 880 // See if this is a known constant. 881 const TryResult &KnownVal = TryEvaluateBool(I->getCond()); 882 883 // Now add the successors. 884 AddSuccessor(Block, KnownVal.isFalse() ? NULL : ThenBlock); 885 AddSuccessor(Block, KnownVal.isTrue()? NULL : ElseBlock); 886 887 // Add the condition as the last statement in the new block. This may create 888 // new blocks as the condition may contain control-flow. Any newly created 889 // blocks will be pointed to be "Block". 890 Block = addStmt(I->getCond()); 891 892 // Finally, if the IfStmt contains a condition variable, add both the IfStmt 893 // and the condition variable initialization to the CFG. 894 if (VarDecl *VD = I->getConditionVariable()) { 895 if (Expr *Init = VD->getInit()) { 896 autoCreateBlock(); 897 AppendStmt(Block, I, AddStmtChoice::AlwaysAdd); 898 addStmt(Init); 899 } 900 } 901 902 return Block; 903} 904 905 906CFGBlock* CFGBuilder::VisitReturnStmt(ReturnStmt* R) { 907 // If we were in the middle of a block we stop processing that block. 908 // 909 // NOTE: If a "return" appears in the middle of a block, this means that the 910 // code afterwards is DEAD (unreachable). We still keep a basic block 911 // for that code; a simple "mark-and-sweep" from the entry block will be 912 // able to report such dead blocks. 913 if (Block) 914 FinishBlock(Block); 915 916 // Create the new block. 917 Block = createBlock(false); 918 919 // The Exit block is the only successor. 920 AddSuccessor(Block, &cfg->getExit()); 921 922 // Add the return statement to the block. This may create new blocks if R 923 // contains control-flow (short-circuit operations). 924 return VisitStmt(R, AddStmtChoice::AlwaysAdd); 925} 926 927CFGBlock* CFGBuilder::VisitLabelStmt(LabelStmt* L) { 928 // Get the block of the labeled statement. Add it to our map. 929 addStmt(L->getSubStmt()); 930 CFGBlock* LabelBlock = Block; 931 932 if (!LabelBlock) // This can happen when the body is empty, i.e. 933 LabelBlock = createBlock(); // scopes that only contains NullStmts. 934 935 assert(LabelMap.find(L) == LabelMap.end() && "label already in map"); 936 LabelMap[ L ] = LabelBlock; 937 938 // Labels partition blocks, so this is the end of the basic block we were 939 // processing (L is the block's label). Because this is label (and we have 940 // already processed the substatement) there is no extra control-flow to worry 941 // about. 942 LabelBlock->setLabel(L); 943 if (!FinishBlock(LabelBlock)) 944 return 0; 945 946 // We set Block to NULL to allow lazy creation of a new block (if necessary); 947 Block = NULL; 948 949 // This block is now the implicit successor of other blocks. 950 Succ = LabelBlock; 951 952 return LabelBlock; 953} 954 955CFGBlock* CFGBuilder::VisitGotoStmt(GotoStmt* G) { 956 // Goto is a control-flow statement. Thus we stop processing the current 957 // block and create a new one. 958 if (Block) 959 FinishBlock(Block); 960 961 Block = createBlock(false); 962 Block->setTerminator(G); 963 964 // If we already know the mapping to the label block add the successor now. 965 LabelMapTy::iterator I = LabelMap.find(G->getLabel()); 966 967 if (I == LabelMap.end()) 968 // We will need to backpatch this block later. 969 BackpatchBlocks.push_back(Block); 970 else 971 AddSuccessor(Block, I->second); 972 973 return Block; 974} 975 976CFGBlock* CFGBuilder::VisitForStmt(ForStmt* F) { 977 CFGBlock* LoopSuccessor = NULL; 978 979 // "for" is a control-flow statement. Thus we stop processing the current 980 // block. 981 if (Block) { 982 if (!FinishBlock(Block)) 983 return 0; 984 LoopSuccessor = Block; 985 } else 986 LoopSuccessor = Succ; 987 988 // Because of short-circuit evaluation, the condition of the loop can span 989 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 990 // evaluate the condition. 991 CFGBlock* ExitConditionBlock = createBlock(false); 992 CFGBlock* EntryConditionBlock = ExitConditionBlock; 993 994 // Set the terminator for the "exit" condition block. 995 ExitConditionBlock->setTerminator(F); 996 997 // Now add the actual condition to the condition block. Because the condition 998 // itself may contain control-flow, new blocks may be created. 999 if (Stmt* C = F->getCond()) { 1000 Block = ExitConditionBlock; 1001 EntryConditionBlock = addStmt(C); 1002 assert(Block == EntryConditionBlock); 1003 1004 // If this block contains a condition variable, add both the condition 1005 // variable and initializer to the CFG. 1006 if (VarDecl *VD = F->getConditionVariable()) { 1007 if (Expr *Init = VD->getInit()) { 1008 autoCreateBlock(); 1009 AppendStmt(Block, F, AddStmtChoice::AlwaysAdd); 1010 EntryConditionBlock = addStmt(Init); 1011 assert(Block == EntryConditionBlock); 1012 } 1013 } 1014 1015 if (Block) { 1016 if (!FinishBlock(EntryConditionBlock)) 1017 return 0; 1018 } 1019 } 1020 1021 // The condition block is the implicit successor for the loop body as well as 1022 // any code above the loop. 1023 Succ = EntryConditionBlock; 1024 1025 // See if this is a known constant. 1026 TryResult KnownVal(true); 1027 1028 if (F->getCond()) 1029 KnownVal = TryEvaluateBool(F->getCond()); 1030 1031 // Now create the loop body. 1032 { 1033 assert(F->getBody()); 1034 1035 // Save the current values for Block, Succ, and continue and break targets 1036 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1037 save_continue(ContinueTargetBlock), 1038 save_break(BreakTargetBlock); 1039 1040 // Create a new block to contain the (bottom) of the loop body. 1041 Block = NULL; 1042 1043 if (Stmt* I = F->getInc()) { 1044 // Generate increment code in its own basic block. This is the target of 1045 // continue statements. 1046 Succ = addStmt(I); 1047 } else { 1048 // No increment code. Create a special, empty, block that is used as the 1049 // target block for "looping back" to the start of the loop. 1050 assert(Succ == EntryConditionBlock); 1051 Succ = createBlock(); 1052 } 1053 1054 // Finish up the increment (or empty) block if it hasn't been already. 1055 if (Block) { 1056 assert(Block == Succ); 1057 if (!FinishBlock(Block)) 1058 return 0; 1059 Block = 0; 1060 } 1061 1062 ContinueTargetBlock = Succ; 1063 1064 // The starting block for the loop increment is the block that should 1065 // represent the 'loop target' for looping back to the start of the loop. 1066 ContinueTargetBlock->setLoopTarget(F); 1067 1068 // All breaks should go to the code following the loop. 1069 BreakTargetBlock = LoopSuccessor; 1070 1071 // Now populate the body block, and in the process create new blocks as we 1072 // walk the body of the loop. 1073 CFGBlock* BodyBlock = addStmt(F->getBody()); 1074 1075 if (!BodyBlock) 1076 BodyBlock = ContinueTargetBlock; // can happen for "for (...;...;...) ;" 1077 else if (Block && !FinishBlock(BodyBlock)) 1078 return 0; 1079 1080 // This new body block is a successor to our "exit" condition block. 1081 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1082 } 1083 1084 // Link up the condition block with the code that follows the loop. (the 1085 // false branch). 1086 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1087 1088 // If the loop contains initialization, create a new block for those 1089 // statements. This block can also contain statements that precede the loop. 1090 if (Stmt* I = F->getInit()) { 1091 Block = createBlock(); 1092 return addStmt(I); 1093 } else { 1094 // There is no loop initialization. We are thus basically a while loop. 1095 // NULL out Block to force lazy block construction. 1096 Block = NULL; 1097 Succ = EntryConditionBlock; 1098 return EntryConditionBlock; 1099 } 1100} 1101 1102CFGBlock *CFGBuilder::VisitMemberExpr(MemberExpr *M, AddStmtChoice asc) { 1103 if (asc.alwaysAdd()) { 1104 autoCreateBlock(); 1105 AppendStmt(Block, M, asc); 1106 } 1107 return Visit(M->getBase(), 1108 M->isArrow() ? AddStmtChoice::NotAlwaysAdd 1109 : AddStmtChoice::AsLValueNotAlwaysAdd); 1110} 1111 1112CFGBlock* CFGBuilder::VisitObjCForCollectionStmt(ObjCForCollectionStmt* S) { 1113 // Objective-C fast enumeration 'for' statements: 1114 // http://developer.apple.com/documentation/Cocoa/Conceptual/ObjectiveC 1115 // 1116 // for ( Type newVariable in collection_expression ) { statements } 1117 // 1118 // becomes: 1119 // 1120 // prologue: 1121 // 1. collection_expression 1122 // T. jump to loop_entry 1123 // loop_entry: 1124 // 1. side-effects of element expression 1125 // 1. ObjCForCollectionStmt [performs binding to newVariable] 1126 // T. ObjCForCollectionStmt TB, FB [jumps to TB if newVariable != nil] 1127 // TB: 1128 // statements 1129 // T. jump to loop_entry 1130 // FB: 1131 // what comes after 1132 // 1133 // and 1134 // 1135 // Type existingItem; 1136 // for ( existingItem in expression ) { statements } 1137 // 1138 // becomes: 1139 // 1140 // the same with newVariable replaced with existingItem; the binding works 1141 // the same except that for one ObjCForCollectionStmt::getElement() returns 1142 // a DeclStmt and the other returns a DeclRefExpr. 1143 // 1144 1145 CFGBlock* LoopSuccessor = 0; 1146 1147 if (Block) { 1148 if (!FinishBlock(Block)) 1149 return 0; 1150 LoopSuccessor = Block; 1151 Block = 0; 1152 } else 1153 LoopSuccessor = Succ; 1154 1155 // Build the condition blocks. 1156 CFGBlock* ExitConditionBlock = createBlock(false); 1157 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1158 1159 // Set the terminator for the "exit" condition block. 1160 ExitConditionBlock->setTerminator(S); 1161 1162 // The last statement in the block should be the ObjCForCollectionStmt, which 1163 // performs the actual binding to 'element' and determines if there are any 1164 // more items in the collection. 1165 AppendStmt(ExitConditionBlock, S); 1166 Block = ExitConditionBlock; 1167 1168 // Walk the 'element' expression to see if there are any side-effects. We 1169 // generate new blocks as necesary. We DON'T add the statement by default to 1170 // the CFG unless it contains control-flow. 1171 EntryConditionBlock = Visit(S->getElement(), AddStmtChoice::NotAlwaysAdd); 1172 if (Block) { 1173 if (!FinishBlock(EntryConditionBlock)) 1174 return 0; 1175 Block = 0; 1176 } 1177 1178 // The condition block is the implicit successor for the loop body as well as 1179 // any code above the loop. 1180 Succ = EntryConditionBlock; 1181 1182 // Now create the true branch. 1183 { 1184 // Save the current values for Succ, continue and break targets. 1185 SaveAndRestore<CFGBlock*> save_Succ(Succ), 1186 save_continue(ContinueTargetBlock), save_break(BreakTargetBlock); 1187 1188 BreakTargetBlock = LoopSuccessor; 1189 ContinueTargetBlock = EntryConditionBlock; 1190 1191 CFGBlock* BodyBlock = addStmt(S->getBody()); 1192 1193 if (!BodyBlock) 1194 BodyBlock = EntryConditionBlock; // can happen for "for (X in Y) ;" 1195 else if (Block) { 1196 if (!FinishBlock(BodyBlock)) 1197 return 0; 1198 } 1199 1200 // This new body block is a successor to our "exit" condition block. 1201 AddSuccessor(ExitConditionBlock, BodyBlock); 1202 } 1203 1204 // Link up the condition block with the code that follows the loop. 1205 // (the false branch). 1206 AddSuccessor(ExitConditionBlock, LoopSuccessor); 1207 1208 // Now create a prologue block to contain the collection expression. 1209 Block = createBlock(); 1210 return addStmt(S->getCollection()); 1211} 1212 1213CFGBlock* CFGBuilder::VisitObjCAtSynchronizedStmt(ObjCAtSynchronizedStmt* S) { 1214 // FIXME: Add locking 'primitives' to CFG for @synchronized. 1215 1216 // Inline the body. 1217 CFGBlock *SyncBlock = addStmt(S->getSynchBody()); 1218 1219 // The sync body starts its own basic block. This makes it a little easier 1220 // for diagnostic clients. 1221 if (SyncBlock) { 1222 if (!FinishBlock(SyncBlock)) 1223 return 0; 1224 1225 Block = 0; 1226 Succ = SyncBlock; 1227 } 1228 1229 // Inline the sync expression. 1230 return addStmt(S->getSynchExpr()); 1231} 1232 1233CFGBlock* CFGBuilder::VisitObjCAtTryStmt(ObjCAtTryStmt* S) { 1234 // FIXME 1235 return NYS(); 1236} 1237 1238CFGBlock* CFGBuilder::VisitWhileStmt(WhileStmt* W) { 1239 CFGBlock* LoopSuccessor = NULL; 1240 1241 // "while" is a control-flow statement. Thus we stop processing the current 1242 // block. 1243 if (Block) { 1244 if (!FinishBlock(Block)) 1245 return 0; 1246 LoopSuccessor = Block; 1247 } else 1248 LoopSuccessor = Succ; 1249 1250 // Because of short-circuit evaluation, the condition of the loop can span 1251 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1252 // evaluate the condition. 1253 CFGBlock* ExitConditionBlock = createBlock(false); 1254 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1255 1256 // Set the terminator for the "exit" condition block. 1257 ExitConditionBlock->setTerminator(W); 1258 1259 // Now add the actual condition to the condition block. Because the condition 1260 // itself may contain control-flow, new blocks may be created. Thus we update 1261 // "Succ" after adding the condition. 1262 if (Stmt* C = W->getCond()) { 1263 Block = ExitConditionBlock; 1264 EntryConditionBlock = addStmt(C); 1265 assert(Block == EntryConditionBlock); 1266 1267 // If this block contains a condition variable, add both the condition 1268 // variable and initializer to the CFG. 1269 if (VarDecl *VD = W->getConditionVariable()) { 1270 if (Expr *Init = VD->getInit()) { 1271 autoCreateBlock(); 1272 AppendStmt(Block, W, AddStmtChoice::AlwaysAdd); 1273 EntryConditionBlock = addStmt(Init); 1274 assert(Block == EntryConditionBlock); 1275 } 1276 } 1277 1278 if (Block) { 1279 if (!FinishBlock(EntryConditionBlock)) 1280 return 0; 1281 } 1282 } 1283 1284 // The condition block is the implicit successor for the loop body as well as 1285 // any code above the loop. 1286 Succ = EntryConditionBlock; 1287 1288 // See if this is a known constant. 1289 const TryResult& KnownVal = TryEvaluateBool(W->getCond()); 1290 1291 // Process the loop body. 1292 { 1293 assert(W->getBody()); 1294 1295 // Save the current values for Block, Succ, and continue and break targets 1296 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1297 save_continue(ContinueTargetBlock), 1298 save_break(BreakTargetBlock); 1299 1300 // Create an empty block to represent the transition block for looping back 1301 // to the head of the loop. 1302 Block = 0; 1303 assert(Succ == EntryConditionBlock); 1304 Succ = createBlock(); 1305 Succ->setLoopTarget(W); 1306 ContinueTargetBlock = Succ; 1307 1308 // All breaks should go to the code following the loop. 1309 BreakTargetBlock = LoopSuccessor; 1310 1311 // NULL out Block to force lazy instantiation of blocks for the body. 1312 Block = NULL; 1313 1314 // Create the body. The returned block is the entry to the loop body. 1315 CFGBlock* BodyBlock = addStmt(W->getBody()); 1316 1317 if (!BodyBlock) 1318 BodyBlock = ContinueTargetBlock; // can happen for "while(...) ;" 1319 else if (Block) { 1320 if (!FinishBlock(BodyBlock)) 1321 return 0; 1322 } 1323 1324 // Add the loop body entry as a successor to the condition. 1325 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : BodyBlock); 1326 } 1327 1328 // Link up the condition block with the code that follows the loop. (the 1329 // false branch). 1330 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1331 1332 // There can be no more statements in the condition block since we loop back 1333 // to this block. NULL out Block to force lazy creation of another block. 1334 Block = NULL; 1335 1336 // Return the condition block, which is the dominating block for the loop. 1337 Succ = EntryConditionBlock; 1338 return EntryConditionBlock; 1339} 1340 1341 1342CFGBlock *CFGBuilder::VisitObjCAtCatchStmt(ObjCAtCatchStmt* S) { 1343 // FIXME: For now we pretend that @catch and the code it contains does not 1344 // exit. 1345 return Block; 1346} 1347 1348CFGBlock* CFGBuilder::VisitObjCAtThrowStmt(ObjCAtThrowStmt* S) { 1349 // FIXME: This isn't complete. We basically treat @throw like a return 1350 // statement. 1351 1352 // If we were in the middle of a block we stop processing that block. 1353 if (Block && !FinishBlock(Block)) 1354 return 0; 1355 1356 // Create the new block. 1357 Block = createBlock(false); 1358 1359 // The Exit block is the only successor. 1360 AddSuccessor(Block, &cfg->getExit()); 1361 1362 // Add the statement to the block. This may create new blocks if S contains 1363 // control-flow (short-circuit operations). 1364 return VisitStmt(S, AddStmtChoice::AlwaysAdd); 1365} 1366 1367CFGBlock* CFGBuilder::VisitCXXThrowExpr(CXXThrowExpr* T) { 1368 // If we were in the middle of a block we stop processing that block. 1369 if (Block && !FinishBlock(Block)) 1370 return 0; 1371 1372 // Create the new block. 1373 Block = createBlock(false); 1374 1375 if (TryTerminatedBlock) 1376 // The current try statement is the only successor. 1377 AddSuccessor(Block, TryTerminatedBlock); 1378 else 1379 // otherwise the Exit block is the only successor. 1380 AddSuccessor(Block, &cfg->getExit()); 1381 1382 // Add the statement to the block. This may create new blocks if S contains 1383 // control-flow (short-circuit operations). 1384 return VisitStmt(T, AddStmtChoice::AlwaysAdd); 1385} 1386 1387CFGBlock *CFGBuilder::VisitDoStmt(DoStmt* D) { 1388 CFGBlock* LoopSuccessor = NULL; 1389 1390 // "do...while" is a control-flow statement. Thus we stop processing the 1391 // current block. 1392 if (Block) { 1393 if (!FinishBlock(Block)) 1394 return 0; 1395 LoopSuccessor = Block; 1396 } else 1397 LoopSuccessor = Succ; 1398 1399 // Because of short-circuit evaluation, the condition of the loop can span 1400 // multiple basic blocks. Thus we need the "Entry" and "Exit" blocks that 1401 // evaluate the condition. 1402 CFGBlock* ExitConditionBlock = createBlock(false); 1403 CFGBlock* EntryConditionBlock = ExitConditionBlock; 1404 1405 // Set the terminator for the "exit" condition block. 1406 ExitConditionBlock->setTerminator(D); 1407 1408 // Now add the actual condition to the condition block. Because the condition 1409 // itself may contain control-flow, new blocks may be created. 1410 if (Stmt* C = D->getCond()) { 1411 Block = ExitConditionBlock; 1412 EntryConditionBlock = addStmt(C); 1413 if (Block) { 1414 if (!FinishBlock(EntryConditionBlock)) 1415 return 0; 1416 } 1417 } 1418 1419 // The condition block is the implicit successor for the loop body. 1420 Succ = EntryConditionBlock; 1421 1422 // See if this is a known constant. 1423 const TryResult &KnownVal = TryEvaluateBool(D->getCond()); 1424 1425 // Process the loop body. 1426 CFGBlock* BodyBlock = NULL; 1427 { 1428 assert(D->getBody()); 1429 1430 // Save the current values for Block, Succ, and continue and break targets 1431 SaveAndRestore<CFGBlock*> save_Block(Block), save_Succ(Succ), 1432 save_continue(ContinueTargetBlock), 1433 save_break(BreakTargetBlock); 1434 1435 // All continues within this loop should go to the condition block 1436 ContinueTargetBlock = EntryConditionBlock; 1437 1438 // All breaks should go to the code following the loop. 1439 BreakTargetBlock = LoopSuccessor; 1440 1441 // NULL out Block to force lazy instantiation of blocks for the body. 1442 Block = NULL; 1443 1444 // Create the body. The returned block is the entry to the loop body. 1445 BodyBlock = addStmt(D->getBody()); 1446 1447 if (!BodyBlock) 1448 BodyBlock = EntryConditionBlock; // can happen for "do ; while(...)" 1449 else if (Block) { 1450 if (!FinishBlock(BodyBlock)) 1451 return 0; 1452 } 1453 1454 // Add an intermediate block between the BodyBlock and the 1455 // ExitConditionBlock to represent the "loop back" transition. Create an 1456 // empty block to represent the transition block for looping back to the 1457 // head of the loop. 1458 // FIXME: Can we do this more efficiently without adding another block? 1459 Block = NULL; 1460 Succ = BodyBlock; 1461 CFGBlock *LoopBackBlock = createBlock(); 1462 LoopBackBlock->setLoopTarget(D); 1463 1464 // Add the loop body entry as a successor to the condition. 1465 AddSuccessor(ExitConditionBlock, KnownVal.isFalse() ? NULL : LoopBackBlock); 1466 } 1467 1468 // Link up the condition block with the code that follows the loop. 1469 // (the false branch). 1470 AddSuccessor(ExitConditionBlock, KnownVal.isTrue() ? NULL : LoopSuccessor); 1471 1472 // There can be no more statements in the body block(s) since we loop back to 1473 // the body. NULL out Block to force lazy creation of another block. 1474 Block = NULL; 1475 1476 // Return the loop body, which is the dominating block for the loop. 1477 Succ = BodyBlock; 1478 return BodyBlock; 1479} 1480 1481CFGBlock* CFGBuilder::VisitContinueStmt(ContinueStmt* C) { 1482 // "continue" is a control-flow statement. Thus we stop processing the 1483 // current block. 1484 if (Block && !FinishBlock(Block)) 1485 return 0; 1486 1487 // Now create a new block that ends with the continue statement. 1488 Block = createBlock(false); 1489 Block->setTerminator(C); 1490 1491 // If there is no target for the continue, then we are looking at an 1492 // incomplete AST. This means the CFG cannot be constructed. 1493 if (ContinueTargetBlock) 1494 AddSuccessor(Block, ContinueTargetBlock); 1495 else 1496 badCFG = true; 1497 1498 return Block; 1499} 1500 1501CFGBlock *CFGBuilder::VisitSizeOfAlignOfExpr(SizeOfAlignOfExpr *E, 1502 AddStmtChoice asc) { 1503 1504 if (asc.alwaysAdd()) { 1505 autoCreateBlock(); 1506 AppendStmt(Block, E); 1507 } 1508 1509 // VLA types have expressions that must be evaluated. 1510 if (E->isArgumentType()) { 1511 for (VariableArrayType* VA = FindVA(E->getArgumentType().getTypePtr()); 1512 VA != 0; VA = FindVA(VA->getElementType().getTypePtr())) 1513 addStmt(VA->getSizeExpr()); 1514 } 1515 1516 return Block; 1517} 1518 1519/// VisitStmtExpr - Utility method to handle (nested) statement 1520/// expressions (a GCC extension). 1521CFGBlock* CFGBuilder::VisitStmtExpr(StmtExpr *SE, AddStmtChoice asc) { 1522 if (asc.alwaysAdd()) { 1523 autoCreateBlock(); 1524 AppendStmt(Block, SE); 1525 } 1526 return VisitCompoundStmt(SE->getSubStmt()); 1527} 1528 1529CFGBlock* CFGBuilder::VisitSwitchStmt(SwitchStmt* Terminator) { 1530 // "switch" is a control-flow statement. Thus we stop processing the current 1531 // block. 1532 CFGBlock* SwitchSuccessor = NULL; 1533 1534 if (Block) { 1535 if (!FinishBlock(Block)) 1536 return 0; 1537 SwitchSuccessor = Block; 1538 } else SwitchSuccessor = Succ; 1539 1540 // Save the current "switch" context. 1541 SaveAndRestore<CFGBlock*> save_switch(SwitchTerminatedBlock), 1542 save_break(BreakTargetBlock), 1543 save_default(DefaultCaseBlock); 1544 1545 // Set the "default" case to be the block after the switch statement. If the 1546 // switch statement contains a "default:", this value will be overwritten with 1547 // the block for that code. 1548 DefaultCaseBlock = SwitchSuccessor; 1549 1550 // Create a new block that will contain the switch statement. 1551 SwitchTerminatedBlock = createBlock(false); 1552 1553 // Now process the switch body. The code after the switch is the implicit 1554 // successor. 1555 Succ = SwitchSuccessor; 1556 BreakTargetBlock = SwitchSuccessor; 1557 1558 // When visiting the body, the case statements should automatically get linked 1559 // up to the switch. We also don't keep a pointer to the body, since all 1560 // control-flow from the switch goes to case/default statements. 1561 assert(Terminator->getBody() && "switch must contain a non-NULL body"); 1562 Block = NULL; 1563 CFGBlock *BodyBlock = addStmt(Terminator->getBody()); 1564 if (Block) { 1565 if (!FinishBlock(BodyBlock)) 1566 return 0; 1567 } 1568 1569 // If we have no "default:" case, the default transition is to the code 1570 // following the switch body. 1571 AddSuccessor(SwitchTerminatedBlock, DefaultCaseBlock); 1572 1573 // Add the terminator and condition in the switch block. 1574 SwitchTerminatedBlock->setTerminator(Terminator); 1575 assert(Terminator->getCond() && "switch condition must be non-NULL"); 1576 Block = SwitchTerminatedBlock; 1577 Block = addStmt(Terminator->getCond()); 1578 1579 // Finally, if the SwitchStmt contains a condition variable, add both the 1580 // SwitchStmt and the condition variable initialization to the CFG. 1581 if (VarDecl *VD = Terminator->getConditionVariable()) { 1582 if (Expr *Init = VD->getInit()) { 1583 autoCreateBlock(); 1584 AppendStmt(Block, Terminator, AddStmtChoice::AlwaysAdd); 1585 addStmt(Init); 1586 } 1587 } 1588 1589 return Block; 1590} 1591 1592CFGBlock* CFGBuilder::VisitCaseStmt(CaseStmt* CS) { 1593 // CaseStmts are essentially labels, so they are the first statement in a 1594 // block. 1595 1596 if (CS->getSubStmt()) 1597 addStmt(CS->getSubStmt()); 1598 1599 CFGBlock* CaseBlock = Block; 1600 if (!CaseBlock) 1601 CaseBlock = createBlock(); 1602 1603 // Cases statements partition blocks, so this is the top of the basic block we 1604 // were processing (the "case XXX:" is the label). 1605 CaseBlock->setLabel(CS); 1606 1607 if (!FinishBlock(CaseBlock)) 1608 return 0; 1609 1610 // Add this block to the list of successors for the block with the switch 1611 // statement. 1612 assert(SwitchTerminatedBlock); 1613 AddSuccessor(SwitchTerminatedBlock, CaseBlock); 1614 1615 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1616 Block = NULL; 1617 1618 // This block is now the implicit successor of other blocks. 1619 Succ = CaseBlock; 1620 1621 return CaseBlock; 1622} 1623 1624CFGBlock* CFGBuilder::VisitDefaultStmt(DefaultStmt* Terminator) { 1625 if (Terminator->getSubStmt()) 1626 addStmt(Terminator->getSubStmt()); 1627 1628 DefaultCaseBlock = Block; 1629 1630 if (!DefaultCaseBlock) 1631 DefaultCaseBlock = createBlock(); 1632 1633 // Default statements partition blocks, so this is the top of the basic block 1634 // we were processing (the "default:" is the label). 1635 DefaultCaseBlock->setLabel(Terminator); 1636 1637 if (!FinishBlock(DefaultCaseBlock)) 1638 return 0; 1639 1640 // Unlike case statements, we don't add the default block to the successors 1641 // for the switch statement immediately. This is done when we finish 1642 // processing the switch statement. This allows for the default case 1643 // (including a fall-through to the code after the switch statement) to always 1644 // be the last successor of a switch-terminated block. 1645 1646 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1647 Block = NULL; 1648 1649 // This block is now the implicit successor of other blocks. 1650 Succ = DefaultCaseBlock; 1651 1652 return DefaultCaseBlock; 1653} 1654 1655CFGBlock *CFGBuilder::VisitCXXTryStmt(CXXTryStmt *Terminator) { 1656 // "try"/"catch" is a control-flow statement. Thus we stop processing the 1657 // current block. 1658 CFGBlock* TrySuccessor = NULL; 1659 1660 if (Block) { 1661 if (!FinishBlock(Block)) 1662 return 0; 1663 TrySuccessor = Block; 1664 } else TrySuccessor = Succ; 1665 1666 CFGBlock *PrevTryTerminatedBlock = TryTerminatedBlock; 1667 1668 // Create a new block that will contain the try statement. 1669 CFGBlock *NewTryTerminatedBlock = createBlock(false); 1670 // Add the terminator in the try block. 1671 NewTryTerminatedBlock->setTerminator(Terminator); 1672 1673 bool HasCatchAll = false; 1674 for (unsigned h = 0; h <Terminator->getNumHandlers(); ++h) { 1675 // The code after the try is the implicit successor. 1676 Succ = TrySuccessor; 1677 CXXCatchStmt *CS = Terminator->getHandler(h); 1678 if (CS->getExceptionDecl() == 0) { 1679 HasCatchAll = true; 1680 } 1681 Block = NULL; 1682 CFGBlock *CatchBlock = VisitCXXCatchStmt(CS); 1683 if (CatchBlock == 0) 1684 return 0; 1685 // Add this block to the list of successors for the block with the try 1686 // statement. 1687 AddSuccessor(NewTryTerminatedBlock, CatchBlock); 1688 } 1689 if (!HasCatchAll) { 1690 if (PrevTryTerminatedBlock) 1691 AddSuccessor(NewTryTerminatedBlock, PrevTryTerminatedBlock); 1692 else 1693 AddSuccessor(NewTryTerminatedBlock, &cfg->getExit()); 1694 } 1695 1696 // The code after the try is the implicit successor. 1697 Succ = TrySuccessor; 1698 1699 // Save the current "try" context. 1700 SaveAndRestore<CFGBlock*> save_try(TryTerminatedBlock); 1701 TryTerminatedBlock = NewTryTerminatedBlock; 1702 1703 assert(Terminator->getTryBlock() && "try must contain a non-NULL body"); 1704 Block = NULL; 1705 Block = addStmt(Terminator->getTryBlock()); 1706 return Block; 1707} 1708 1709CFGBlock* CFGBuilder::VisitCXXCatchStmt(CXXCatchStmt* CS) { 1710 // CXXCatchStmt are treated like labels, so they are the first statement in a 1711 // block. 1712 1713 if (CS->getHandlerBlock()) 1714 addStmt(CS->getHandlerBlock()); 1715 1716 CFGBlock* CatchBlock = Block; 1717 if (!CatchBlock) 1718 CatchBlock = createBlock(); 1719 1720 CatchBlock->setLabel(CS); 1721 1722 if (!FinishBlock(CatchBlock)) 1723 return 0; 1724 1725 // We set Block to NULL to allow lazy creation of a new block (if necessary) 1726 Block = NULL; 1727 1728 return CatchBlock; 1729} 1730 1731CFGBlock *CFGBuilder::VisitCXXMemberCallExpr(CXXMemberCallExpr *C, 1732 AddStmtChoice asc) { 1733 AddStmtChoice::Kind K = asc.asLValue() ? AddStmtChoice::AlwaysAddAsLValue 1734 : AddStmtChoice::AlwaysAdd; 1735 autoCreateBlock(); 1736 AppendStmt(Block, C, AddStmtChoice(K)); 1737 return VisitChildren(C); 1738} 1739 1740CFGBlock* CFGBuilder::VisitIndirectGotoStmt(IndirectGotoStmt* I) { 1741 // Lazily create the indirect-goto dispatch block if there isn't one already. 1742 CFGBlock* IBlock = cfg->getIndirectGotoBlock(); 1743 1744 if (!IBlock) { 1745 IBlock = createBlock(false); 1746 cfg->setIndirectGotoBlock(IBlock); 1747 } 1748 1749 // IndirectGoto is a control-flow statement. Thus we stop processing the 1750 // current block and create a new one. 1751 if (Block && !FinishBlock(Block)) 1752 return 0; 1753 1754 Block = createBlock(false); 1755 Block->setTerminator(I); 1756 AddSuccessor(Block, IBlock); 1757 return addStmt(I->getTarget()); 1758} 1759 1760} // end anonymous namespace 1761 1762/// createBlock - Constructs and adds a new CFGBlock to the CFG. The block has 1763/// no successors or predecessors. If this is the first block created in the 1764/// CFG, it is automatically set to be the Entry and Exit of the CFG. 1765CFGBlock* CFG::createBlock() { 1766 bool first_block = begin() == end(); 1767 1768 // Create the block. 1769 CFGBlock *Mem = getAllocator().Allocate<CFGBlock>(); 1770 new (Mem) CFGBlock(NumBlockIDs++, BlkBVC); 1771 Blocks.push_back(Mem, BlkBVC); 1772 1773 // If this is the first block, set it as the Entry and Exit. 1774 if (first_block) 1775 Entry = Exit = &back(); 1776 1777 // Return the block. 1778 return &back(); 1779} 1780 1781/// buildCFG - Constructs a CFG from an AST. Ownership of the returned 1782/// CFG is returned to the caller. 1783CFG* CFG::buildCFG(const Decl *D, Stmt* Statement, ASTContext *C, 1784 bool AddEHEdges, bool AddScopes) { 1785 CFGBuilder Builder; 1786 return Builder.buildCFG(D, Statement, C, AddEHEdges, AddScopes); 1787} 1788 1789//===----------------------------------------------------------------------===// 1790// CFG: Queries for BlkExprs. 1791//===----------------------------------------------------------------------===// 1792 1793namespace { 1794 typedef llvm::DenseMap<const Stmt*,unsigned> BlkExprMapTy; 1795} 1796 1797static void FindSubExprAssignments(Stmt *S, 1798 llvm::SmallPtrSet<Expr*,50>& Set) { 1799 if (!S) 1800 return; 1801 1802 for (Stmt::child_iterator I=S->child_begin(), E=S->child_end(); I!=E; ++I) { 1803 Stmt *child = *I; 1804 if (!child) 1805 continue; 1806 1807 if (BinaryOperator* B = dyn_cast<BinaryOperator>(child)) 1808 if (B->isAssignmentOp()) Set.insert(B); 1809 1810 FindSubExprAssignments(child, Set); 1811 } 1812} 1813 1814static BlkExprMapTy* PopulateBlkExprMap(CFG& cfg) { 1815 BlkExprMapTy* M = new BlkExprMapTy(); 1816 1817 // Look for assignments that are used as subexpressions. These are the only 1818 // assignments that we want to *possibly* register as a block-level 1819 // expression. Basically, if an assignment occurs both in a subexpression and 1820 // at the block-level, it is a block-level expression. 1821 llvm::SmallPtrSet<Expr*,50> SubExprAssignments; 1822 1823 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) 1824 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1825 FindSubExprAssignments(*BI, SubExprAssignments); 1826 1827 for (CFG::iterator I=cfg.begin(), E=cfg.end(); I != E; ++I) { 1828 1829 // Iterate over the statements again on identify the Expr* and Stmt* at the 1830 // block-level that are block-level expressions. 1831 1832 for (CFGBlock::iterator BI=(*I)->begin(), EI=(*I)->end(); BI != EI; ++BI) 1833 if (Expr* Exp = dyn_cast<Expr>(*BI)) { 1834 1835 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Exp)) { 1836 // Assignment expressions that are not nested within another 1837 // expression are really "statements" whose value is never used by 1838 // another expression. 1839 if (B->isAssignmentOp() && !SubExprAssignments.count(Exp)) 1840 continue; 1841 } else if (const StmtExpr* Terminator = dyn_cast<StmtExpr>(Exp)) { 1842 // Special handling for statement expressions. The last statement in 1843 // the statement expression is also a block-level expr. 1844 const CompoundStmt* C = Terminator->getSubStmt(); 1845 if (!C->body_empty()) { 1846 unsigned x = M->size(); 1847 (*M)[C->body_back()] = x; 1848 } 1849 } 1850 1851 unsigned x = M->size(); 1852 (*M)[Exp] = x; 1853 } 1854 1855 // Look at terminators. The condition is a block-level expression. 1856 1857 Stmt* S = (*I)->getTerminatorCondition(); 1858 1859 if (S && M->find(S) == M->end()) { 1860 unsigned x = M->size(); 1861 (*M)[S] = x; 1862 } 1863 } 1864 1865 return M; 1866} 1867 1868CFG::BlkExprNumTy CFG::getBlkExprNum(const Stmt* S) { 1869 assert(S != NULL); 1870 if (!BlkExprMap) { BlkExprMap = (void*) PopulateBlkExprMap(*this); } 1871 1872 BlkExprMapTy* M = reinterpret_cast<BlkExprMapTy*>(BlkExprMap); 1873 BlkExprMapTy::iterator I = M->find(S); 1874 return (I == M->end()) ? CFG::BlkExprNumTy() : CFG::BlkExprNumTy(I->second); 1875} 1876 1877unsigned CFG::getNumBlkExprs() { 1878 if (const BlkExprMapTy* M = reinterpret_cast<const BlkExprMapTy*>(BlkExprMap)) 1879 return M->size(); 1880 else { 1881 // We assume callers interested in the number of BlkExprs will want 1882 // the map constructed if it doesn't already exist. 1883 BlkExprMap = (void*) PopulateBlkExprMap(*this); 1884 return reinterpret_cast<BlkExprMapTy*>(BlkExprMap)->size(); 1885 } 1886} 1887 1888//===----------------------------------------------------------------------===// 1889// Cleanup: CFG dstor. 1890//===----------------------------------------------------------------------===// 1891 1892CFG::~CFG() { 1893 delete reinterpret_cast<const BlkExprMapTy*>(BlkExprMap); 1894} 1895 1896//===----------------------------------------------------------------------===// 1897// CFG pretty printing 1898//===----------------------------------------------------------------------===// 1899 1900namespace { 1901 1902class StmtPrinterHelper : public PrinterHelper { 1903 typedef llvm::DenseMap<Stmt*,std::pair<unsigned,unsigned> > StmtMapTy; 1904 StmtMapTy StmtMap; 1905 signed CurrentBlock; 1906 unsigned CurrentStmt; 1907 const LangOptions &LangOpts; 1908public: 1909 1910 StmtPrinterHelper(const CFG* cfg, const LangOptions &LO) 1911 : CurrentBlock(0), CurrentStmt(0), LangOpts(LO) { 1912 for (CFG::const_iterator I = cfg->begin(), E = cfg->end(); I != E; ++I ) { 1913 unsigned j = 1; 1914 for (CFGBlock::const_iterator BI = (*I)->begin(), BEnd = (*I)->end() ; 1915 BI != BEnd; ++BI, ++j ) 1916 StmtMap[*BI] = std::make_pair((*I)->getBlockID(),j); 1917 } 1918 } 1919 1920 virtual ~StmtPrinterHelper() {} 1921 1922 const LangOptions &getLangOpts() const { return LangOpts; } 1923 void setBlockID(signed i) { CurrentBlock = i; } 1924 void setStmtID(unsigned i) { CurrentStmt = i; } 1925 1926 virtual bool handledStmt(Stmt* Terminator, llvm::raw_ostream& OS) { 1927 1928 StmtMapTy::iterator I = StmtMap.find(Terminator); 1929 1930 if (I == StmtMap.end()) 1931 return false; 1932 1933 if (CurrentBlock >= 0 && I->second.first == (unsigned) CurrentBlock 1934 && I->second.second == CurrentStmt) { 1935 return false; 1936 } 1937 1938 OS << "[B" << I->second.first << "." << I->second.second << "]"; 1939 return true; 1940 } 1941}; 1942} // end anonymous namespace 1943 1944 1945namespace { 1946class CFGBlockTerminatorPrint 1947 : public StmtVisitor<CFGBlockTerminatorPrint,void> { 1948 1949 llvm::raw_ostream& OS; 1950 StmtPrinterHelper* Helper; 1951 PrintingPolicy Policy; 1952public: 1953 CFGBlockTerminatorPrint(llvm::raw_ostream& os, StmtPrinterHelper* helper, 1954 const PrintingPolicy &Policy) 1955 : OS(os), Helper(helper), Policy(Policy) {} 1956 1957 void VisitIfStmt(IfStmt* I) { 1958 OS << "if "; 1959 I->getCond()->printPretty(OS,Helper,Policy); 1960 } 1961 1962 // Default case. 1963 void VisitStmt(Stmt* Terminator) { 1964 Terminator->printPretty(OS, Helper, Policy); 1965 } 1966 1967 void VisitForStmt(ForStmt* F) { 1968 OS << "for (" ; 1969 if (F->getInit()) 1970 OS << "..."; 1971 OS << "; "; 1972 if (Stmt* C = F->getCond()) 1973 C->printPretty(OS, Helper, Policy); 1974 OS << "; "; 1975 if (F->getInc()) 1976 OS << "..."; 1977 OS << ")"; 1978 } 1979 1980 void VisitWhileStmt(WhileStmt* W) { 1981 OS << "while " ; 1982 if (Stmt* C = W->getCond()) 1983 C->printPretty(OS, Helper, Policy); 1984 } 1985 1986 void VisitDoStmt(DoStmt* D) { 1987 OS << "do ... while "; 1988 if (Stmt* C = D->getCond()) 1989 C->printPretty(OS, Helper, Policy); 1990 } 1991 1992 void VisitSwitchStmt(SwitchStmt* Terminator) { 1993 OS << "switch "; 1994 Terminator->getCond()->printPretty(OS, Helper, Policy); 1995 } 1996 1997 void VisitCXXTryStmt(CXXTryStmt* CS) { 1998 OS << "try ..."; 1999 } 2000 2001 void VisitConditionalOperator(ConditionalOperator* C) { 2002 C->getCond()->printPretty(OS, Helper, Policy); 2003 OS << " ? ... : ..."; 2004 } 2005 2006 void VisitChooseExpr(ChooseExpr* C) { 2007 OS << "__builtin_choose_expr( "; 2008 C->getCond()->printPretty(OS, Helper, Policy); 2009 OS << " )"; 2010 } 2011 2012 void VisitIndirectGotoStmt(IndirectGotoStmt* I) { 2013 OS << "goto *"; 2014 I->getTarget()->printPretty(OS, Helper, Policy); 2015 } 2016 2017 void VisitBinaryOperator(BinaryOperator* B) { 2018 if (!B->isLogicalOp()) { 2019 VisitExpr(B); 2020 return; 2021 } 2022 2023 B->getLHS()->printPretty(OS, Helper, Policy); 2024 2025 switch (B->getOpcode()) { 2026 case BinaryOperator::LOr: 2027 OS << " || ..."; 2028 return; 2029 case BinaryOperator::LAnd: 2030 OS << " && ..."; 2031 return; 2032 default: 2033 assert(false && "Invalid logical operator."); 2034 } 2035 } 2036 2037 void VisitExpr(Expr* E) { 2038 E->printPretty(OS, Helper, Policy); 2039 } 2040}; 2041} // end anonymous namespace 2042 2043 2044static void print_stmt(llvm::raw_ostream &OS, StmtPrinterHelper* Helper, 2045 const CFGElement &E) { 2046 Stmt *Terminator = E; 2047 2048 if (E.asStartScope()) { 2049 OS << "start scope\n"; 2050 return; 2051 } 2052 if (E.asEndScope()) { 2053 OS << "end scope\n"; 2054 return; 2055 } 2056 2057 if (Helper) { 2058 // special printing for statement-expressions. 2059 if (StmtExpr* SE = dyn_cast<StmtExpr>(Terminator)) { 2060 CompoundStmt* Sub = SE->getSubStmt(); 2061 2062 if (Sub->child_begin() != Sub->child_end()) { 2063 OS << "({ ... ; "; 2064 Helper->handledStmt(*SE->getSubStmt()->body_rbegin(),OS); 2065 OS << " })\n"; 2066 return; 2067 } 2068 } 2069 2070 // special printing for comma expressions. 2071 if (BinaryOperator* B = dyn_cast<BinaryOperator>(Terminator)) { 2072 if (B->getOpcode() == BinaryOperator::Comma) { 2073 OS << "... , "; 2074 Helper->handledStmt(B->getRHS(),OS); 2075 OS << '\n'; 2076 return; 2077 } 2078 } 2079 } 2080 2081 Terminator->printPretty(OS, Helper, PrintingPolicy(Helper->getLangOpts())); 2082 2083 // Expressions need a newline. 2084 if (isa<Expr>(Terminator)) OS << '\n'; 2085} 2086 2087static void print_block(llvm::raw_ostream& OS, const CFG* cfg, 2088 const CFGBlock& B, 2089 StmtPrinterHelper* Helper, bool print_edges) { 2090 2091 if (Helper) Helper->setBlockID(B.getBlockID()); 2092 2093 // Print the header. 2094 OS << "\n [ B" << B.getBlockID(); 2095 2096 if (&B == &cfg->getEntry()) 2097 OS << " (ENTRY) ]\n"; 2098 else if (&B == &cfg->getExit()) 2099 OS << " (EXIT) ]\n"; 2100 else if (&B == cfg->getIndirectGotoBlock()) 2101 OS << " (INDIRECT GOTO DISPATCH) ]\n"; 2102 else 2103 OS << " ]\n"; 2104 2105 // Print the label of this block. 2106 if (Stmt* Label = const_cast<Stmt*>(B.getLabel())) { 2107 2108 if (print_edges) 2109 OS << " "; 2110 2111 if (LabelStmt* L = dyn_cast<LabelStmt>(Label)) 2112 OS << L->getName(); 2113 else if (CaseStmt* C = dyn_cast<CaseStmt>(Label)) { 2114 OS << "case "; 2115 C->getLHS()->printPretty(OS, Helper, 2116 PrintingPolicy(Helper->getLangOpts())); 2117 if (C->getRHS()) { 2118 OS << " ... "; 2119 C->getRHS()->printPretty(OS, Helper, 2120 PrintingPolicy(Helper->getLangOpts())); 2121 } 2122 } else if (isa<DefaultStmt>(Label)) 2123 OS << "default"; 2124 else if (CXXCatchStmt *CS = dyn_cast<CXXCatchStmt>(Label)) { 2125 OS << "catch ("; 2126 if (CS->getExceptionDecl()) 2127 CS->getExceptionDecl()->print(OS, PrintingPolicy(Helper->getLangOpts()), 2128 0); 2129 else 2130 OS << "..."; 2131 OS << ")"; 2132 2133 } else 2134 assert(false && "Invalid label statement in CFGBlock."); 2135 2136 OS << ":\n"; 2137 } 2138 2139 // Iterate through the statements in the block and print them. 2140 unsigned j = 1; 2141 2142 for (CFGBlock::const_iterator I = B.begin(), E = B.end() ; 2143 I != E ; ++I, ++j ) { 2144 2145 // Print the statement # in the basic block and the statement itself. 2146 if (print_edges) 2147 OS << " "; 2148 2149 OS << llvm::format("%3d", j) << ": "; 2150 2151 if (Helper) 2152 Helper->setStmtID(j); 2153 2154 print_stmt(OS,Helper,*I); 2155 } 2156 2157 // Print the terminator of this block. 2158 if (B.getTerminator()) { 2159 if (print_edges) 2160 OS << " "; 2161 2162 OS << " T: "; 2163 2164 if (Helper) Helper->setBlockID(-1); 2165 2166 CFGBlockTerminatorPrint TPrinter(OS, Helper, 2167 PrintingPolicy(Helper->getLangOpts())); 2168 TPrinter.Visit(const_cast<Stmt*>(B.getTerminator())); 2169 OS << '\n'; 2170 } 2171 2172 if (print_edges) { 2173 // Print the predecessors of this block. 2174 OS << " Predecessors (" << B.pred_size() << "):"; 2175 unsigned i = 0; 2176 2177 for (CFGBlock::const_pred_iterator I = B.pred_begin(), E = B.pred_end(); 2178 I != E; ++I, ++i) { 2179 2180 if (i == 8 || (i-8) == 0) 2181 OS << "\n "; 2182 2183 OS << " B" << (*I)->getBlockID(); 2184 } 2185 2186 OS << '\n'; 2187 2188 // Print the successors of this block. 2189 OS << " Successors (" << B.succ_size() << "):"; 2190 i = 0; 2191 2192 for (CFGBlock::const_succ_iterator I = B.succ_begin(), E = B.succ_end(); 2193 I != E; ++I, ++i) { 2194 2195 if (i == 8 || (i-8) % 10 == 0) 2196 OS << "\n "; 2197 2198 if (*I) 2199 OS << " B" << (*I)->getBlockID(); 2200 else 2201 OS << " NULL"; 2202 } 2203 2204 OS << '\n'; 2205 } 2206} 2207 2208 2209/// dump - A simple pretty printer of a CFG that outputs to stderr. 2210void CFG::dump(const LangOptions &LO) const { print(llvm::errs(), LO); } 2211 2212/// print - A simple pretty printer of a CFG that outputs to an ostream. 2213void CFG::print(llvm::raw_ostream &OS, const LangOptions &LO) const { 2214 StmtPrinterHelper Helper(this, LO); 2215 2216 // Print the entry block. 2217 print_block(OS, this, getEntry(), &Helper, true); 2218 2219 // Iterate through the CFGBlocks and print them one by one. 2220 for (const_iterator I = Blocks.begin(), E = Blocks.end() ; I != E ; ++I) { 2221 // Skip the entry block, because we already printed it. 2222 if (&(**I) == &getEntry() || &(**I) == &getExit()) 2223 continue; 2224 2225 print_block(OS, this, **I, &Helper, true); 2226 } 2227 2228 // Print the exit block. 2229 print_block(OS, this, getExit(), &Helper, true); 2230 OS.flush(); 2231} 2232 2233/// dump - A simply pretty printer of a CFGBlock that outputs to stderr. 2234void CFGBlock::dump(const CFG* cfg, const LangOptions &LO) const { 2235 print(llvm::errs(), cfg, LO); 2236} 2237 2238/// print - A simple pretty printer of a CFGBlock that outputs to an ostream. 2239/// Generally this will only be called from CFG::print. 2240void CFGBlock::print(llvm::raw_ostream& OS, const CFG* cfg, 2241 const LangOptions &LO) const { 2242 StmtPrinterHelper Helper(cfg, LO); 2243 print_block(OS, cfg, *this, &Helper, true); 2244} 2245 2246/// printTerminator - A simple pretty printer of the terminator of a CFGBlock. 2247void CFGBlock::printTerminator(llvm::raw_ostream &OS, 2248 const LangOptions &LO) const { 2249 CFGBlockTerminatorPrint TPrinter(OS, NULL, PrintingPolicy(LO)); 2250 TPrinter.Visit(const_cast<Stmt*>(getTerminator())); 2251} 2252 2253Stmt* CFGBlock::getTerminatorCondition() { 2254 2255 if (!Terminator) 2256 return NULL; 2257 2258 Expr* E = NULL; 2259 2260 switch (Terminator->getStmtClass()) { 2261 default: 2262 break; 2263 2264 case Stmt::ForStmtClass: 2265 E = cast<ForStmt>(Terminator)->getCond(); 2266 break; 2267 2268 case Stmt::WhileStmtClass: 2269 E = cast<WhileStmt>(Terminator)->getCond(); 2270 break; 2271 2272 case Stmt::DoStmtClass: 2273 E = cast<DoStmt>(Terminator)->getCond(); 2274 break; 2275 2276 case Stmt::IfStmtClass: 2277 E = cast<IfStmt>(Terminator)->getCond(); 2278 break; 2279 2280 case Stmt::ChooseExprClass: 2281 E = cast<ChooseExpr>(Terminator)->getCond(); 2282 break; 2283 2284 case Stmt::IndirectGotoStmtClass: 2285 E = cast<IndirectGotoStmt>(Terminator)->getTarget(); 2286 break; 2287 2288 case Stmt::SwitchStmtClass: 2289 E = cast<SwitchStmt>(Terminator)->getCond(); 2290 break; 2291 2292 case Stmt::ConditionalOperatorClass: 2293 E = cast<ConditionalOperator>(Terminator)->getCond(); 2294 break; 2295 2296 case Stmt::BinaryOperatorClass: // '&&' and '||' 2297 E = cast<BinaryOperator>(Terminator)->getLHS(); 2298 break; 2299 2300 case Stmt::ObjCForCollectionStmtClass: 2301 return Terminator; 2302 } 2303 2304 return E ? E->IgnoreParens() : NULL; 2305} 2306 2307bool CFGBlock::hasBinaryBranchTerminator() const { 2308 2309 if (!Terminator) 2310 return false; 2311 2312 Expr* E = NULL; 2313 2314 switch (Terminator->getStmtClass()) { 2315 default: 2316 return false; 2317 2318 case Stmt::ForStmtClass: 2319 case Stmt::WhileStmtClass: 2320 case Stmt::DoStmtClass: 2321 case Stmt::IfStmtClass: 2322 case Stmt::ChooseExprClass: 2323 case Stmt::ConditionalOperatorClass: 2324 case Stmt::BinaryOperatorClass: 2325 return true; 2326 } 2327 2328 return E ? E->IgnoreParens() : NULL; 2329} 2330 2331 2332//===----------------------------------------------------------------------===// 2333// CFG Graphviz Visualization 2334//===----------------------------------------------------------------------===// 2335 2336 2337#ifndef NDEBUG 2338static StmtPrinterHelper* GraphHelper; 2339#endif 2340 2341void CFG::viewCFG(const LangOptions &LO) const { 2342#ifndef NDEBUG 2343 StmtPrinterHelper H(this, LO); 2344 GraphHelper = &H; 2345 llvm::ViewGraph(this,"CFG"); 2346 GraphHelper = NULL; 2347#endif 2348} 2349 2350namespace llvm { 2351template<> 2352struct DOTGraphTraits<const CFG*> : public DefaultDOTGraphTraits { 2353 2354 DOTGraphTraits (bool isSimple=false) : DefaultDOTGraphTraits(isSimple) {} 2355 2356 static std::string getNodeLabel(const CFGBlock* Node, const CFG* Graph) { 2357 2358#ifndef NDEBUG 2359 std::string OutSStr; 2360 llvm::raw_string_ostream Out(OutSStr); 2361 print_block(Out,Graph, *Node, GraphHelper, false); 2362 std::string& OutStr = Out.str(); 2363 2364 if (OutStr[0] == '\n') OutStr.erase(OutStr.begin()); 2365 2366 // Process string output to make it nicer... 2367 for (unsigned i = 0; i != OutStr.length(); ++i) 2368 if (OutStr[i] == '\n') { // Left justify 2369 OutStr[i] = '\\'; 2370 OutStr.insert(OutStr.begin()+i+1, 'l'); 2371 } 2372 2373 return OutStr; 2374#else 2375 return ""; 2376#endif 2377 } 2378}; 2379} // end namespace llvm 2380