CFG.h revision b43d87b0646aa04951056c7e0d1ab9a58eb09f66
1//===--- CFG.h - 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#ifndef LLVM_CLANG_CFG_H 16#define LLVM_CLANG_CFG_H 17 18#include "llvm/ADT/PointerIntPair.h" 19#include "llvm/ADT/GraphTraits.h" 20#include "llvm/Support/Allocator.h" 21#include "llvm/Support/Casting.h" 22#include "llvm/ADT/OwningPtr.h" 23#include "llvm/ADT/DenseMap.h" 24#include "clang/AST/Stmt.h" 25#include "clang/Analysis/Support/BumpVector.h" 26#include "clang/Basic/SourceLocation.h" 27#include <bitset> 28#include <cassert> 29#include <iterator> 30 31namespace clang { 32 class CXXDestructorDecl; 33 class Decl; 34 class Stmt; 35 class Expr; 36 class FieldDecl; 37 class VarDecl; 38 class CXXCtorInitializer; 39 class CXXBaseSpecifier; 40 class CXXBindTemporaryExpr; 41 class CFG; 42 class PrinterHelper; 43 class LangOptions; 44 class ASTContext; 45 46/// CFGElement - Represents a top-level expression in a basic block. 47class CFGElement { 48public: 49 enum Kind { 50 // main kind 51 Invalid, 52 Statement, 53 Initializer, 54 // dtor kind 55 AutomaticObjectDtor, 56 BaseDtor, 57 MemberDtor, 58 TemporaryDtor, 59 DTOR_BEGIN = AutomaticObjectDtor, 60 DTOR_END = TemporaryDtor 61 }; 62 63protected: 64 // The int bits are used to mark the kind. 65 llvm::PointerIntPair<void *, 2> Data1; 66 llvm::PointerIntPair<void *, 2> Data2; 67 68 CFGElement(Kind kind, const void *Ptr1, const void *Ptr2 = 0) 69 : Data1(const_cast<void*>(Ptr1), ((unsigned) kind) & 0x3), 70 Data2(const_cast<void*>(Ptr2), (((unsigned) kind) >> 2) & 0x3) {} 71 72public: 73 CFGElement() {} 74 75 Kind getKind() const { 76 unsigned x = Data2.getInt(); 77 x <<= 2; 78 x |= Data1.getInt(); 79 return (Kind) x; 80 } 81 82 bool isValid() const { return getKind() != Invalid; } 83 84 operator bool() const { return isValid(); } 85 86 template<class ElemTy> const ElemTy *getAs() const { 87 if (llvm::isa<ElemTy>(this)) 88 return static_cast<const ElemTy*>(this); 89 return 0; 90 } 91}; 92 93class CFGStmt : public CFGElement { 94public: 95 CFGStmt(Stmt *S) : CFGElement(Statement, S) {} 96 97 const Stmt *getStmt() const { 98 return static_cast<const Stmt *>(Data1.getPointer()); 99 } 100 101 static bool classof(const CFGElement *E) { 102 return E->getKind() == Statement; 103 } 104}; 105 106/// CFGInitializer - Represents C++ base or member initializer from 107/// constructor's initialization list. 108class CFGInitializer : public CFGElement { 109public: 110 CFGInitializer(CXXCtorInitializer *initializer) 111 : CFGElement(Initializer, initializer) {} 112 113 CXXCtorInitializer* getInitializer() const { 114 return static_cast<CXXCtorInitializer*>(Data1.getPointer()); 115 } 116 117 static bool classof(const CFGElement *E) { 118 return E->getKind() == Initializer; 119 } 120}; 121 122/// CFGImplicitDtor - Represents C++ object destructor implicitly generated 123/// by compiler on various occasions. 124class CFGImplicitDtor : public CFGElement { 125protected: 126 CFGImplicitDtor(Kind kind, const void *data1, const void *data2 = 0) 127 : CFGElement(kind, data1, data2) { 128 assert(kind >= DTOR_BEGIN && kind <= DTOR_END); 129 } 130 131public: 132 const CXXDestructorDecl *getDestructorDecl(ASTContext &astContext) const; 133 bool isNoReturn(ASTContext &astContext) const; 134 135 static bool classof(const CFGElement *E) { 136 Kind kind = E->getKind(); 137 return kind >= DTOR_BEGIN && kind <= DTOR_END; 138 } 139}; 140 141/// CFGAutomaticObjDtor - Represents C++ object destructor implicitly generated 142/// for automatic object or temporary bound to const reference at the point 143/// of leaving its local scope. 144class CFGAutomaticObjDtor: public CFGImplicitDtor { 145public: 146 CFGAutomaticObjDtor(const VarDecl *var, const Stmt *stmt) 147 : CFGImplicitDtor(AutomaticObjectDtor, var, stmt) {} 148 149 const VarDecl *getVarDecl() const { 150 return static_cast<VarDecl*>(Data1.getPointer()); 151 } 152 153 // Get statement end of which triggered the destructor call. 154 const Stmt *getTriggerStmt() const { 155 return static_cast<Stmt*>(Data2.getPointer()); 156 } 157 158 static bool classof(const CFGElement *elem) { 159 return elem->getKind() == AutomaticObjectDtor; 160 } 161}; 162 163/// CFGBaseDtor - Represents C++ object destructor implicitly generated for 164/// base object in destructor. 165class CFGBaseDtor : public CFGImplicitDtor { 166public: 167 CFGBaseDtor(const CXXBaseSpecifier *base) 168 : CFGImplicitDtor(BaseDtor, base) {} 169 170 const CXXBaseSpecifier *getBaseSpecifier() const { 171 return static_cast<const CXXBaseSpecifier*>(Data1.getPointer()); 172 } 173 174 static bool classof(const CFGElement *E) { 175 return E->getKind() == BaseDtor; 176 } 177}; 178 179/// CFGMemberDtor - Represents C++ object destructor implicitly generated for 180/// member object in destructor. 181class CFGMemberDtor : public CFGImplicitDtor { 182public: 183 CFGMemberDtor(const FieldDecl *field) 184 : CFGImplicitDtor(MemberDtor, field, 0) {} 185 186 const FieldDecl *getFieldDecl() const { 187 return static_cast<const FieldDecl*>(Data1.getPointer()); 188 } 189 190 static bool classof(const CFGElement *E) { 191 return E->getKind() == MemberDtor; 192 } 193}; 194 195/// CFGTemporaryDtor - Represents C++ object destructor implicitly generated 196/// at the end of full expression for temporary object. 197class CFGTemporaryDtor : public CFGImplicitDtor { 198public: 199 CFGTemporaryDtor(CXXBindTemporaryExpr *expr) 200 : CFGImplicitDtor(TemporaryDtor, expr, 0) {} 201 202 const CXXBindTemporaryExpr *getBindTemporaryExpr() const { 203 return static_cast<const CXXBindTemporaryExpr *>(Data1.getPointer()); 204 } 205 206 static bool classof(const CFGElement *E) { 207 return E->getKind() == TemporaryDtor; 208 } 209}; 210 211/// CFGTerminator - Represents CFGBlock terminator statement. 212/// 213/// TemporaryDtorsBranch bit is set to true if the terminator marks a branch 214/// in control flow of destructors of temporaries. In this case terminator 215/// statement is the same statement that branches control flow in evaluation 216/// of matching full expression. 217class CFGTerminator { 218 llvm::PointerIntPair<Stmt *, 1> Data; 219public: 220 CFGTerminator() {} 221 CFGTerminator(Stmt *S, bool TemporaryDtorsBranch = false) 222 : Data(S, TemporaryDtorsBranch) {} 223 224 Stmt *getStmt() { return Data.getPointer(); } 225 const Stmt *getStmt() const { return Data.getPointer(); } 226 227 bool isTemporaryDtorsBranch() const { return Data.getInt(); } 228 229 operator Stmt *() { return getStmt(); } 230 operator const Stmt *() const { return getStmt(); } 231 232 Stmt *operator->() { return getStmt(); } 233 const Stmt *operator->() const { return getStmt(); } 234 235 Stmt &operator*() { return *getStmt(); } 236 const Stmt &operator*() const { return *getStmt(); } 237 238 operator bool() const { return getStmt(); } 239}; 240 241/// CFGBlock - Represents a single basic block in a source-level CFG. 242/// It consists of: 243/// 244/// (1) A set of statements/expressions (which may contain subexpressions). 245/// (2) A "terminator" statement (not in the set of statements). 246/// (3) A list of successors and predecessors. 247/// 248/// Terminator: The terminator represents the type of control-flow that occurs 249/// at the end of the basic block. The terminator is a Stmt* referring to an 250/// AST node that has control-flow: if-statements, breaks, loops, etc. 251/// If the control-flow is conditional, the condition expression will appear 252/// within the set of statements in the block (usually the last statement). 253/// 254/// Predecessors: the order in the set of predecessors is arbitrary. 255/// 256/// Successors: the order in the set of successors is NOT arbitrary. We 257/// currently have the following orderings based on the terminator: 258/// 259/// Terminator Successor Ordering 260/// ----------------------------------------------------- 261/// if Then Block; Else Block 262/// ? operator LHS expression; RHS expression 263/// &&, || expression that uses result of && or ||, RHS 264/// 265/// But note that any of that may be NULL in case of optimized-out edges. 266/// 267class CFGBlock { 268 class ElementList { 269 typedef BumpVector<CFGElement> ImplTy; 270 ImplTy Impl; 271 public: 272 ElementList(BumpVectorContext &C) : Impl(C, 4) {} 273 274 typedef std::reverse_iterator<ImplTy::iterator> iterator; 275 typedef std::reverse_iterator<ImplTy::const_iterator> const_iterator; 276 typedef ImplTy::iterator reverse_iterator; 277 typedef ImplTy::const_iterator const_reverse_iterator; 278 typedef ImplTy::const_reference const_reference; 279 280 void push_back(CFGElement e, BumpVectorContext &C) { Impl.push_back(e, C); } 281 reverse_iterator insert(reverse_iterator I, size_t Cnt, CFGElement E, 282 BumpVectorContext &C) { 283 return Impl.insert(I, Cnt, E, C); 284 } 285 286 const_reference front() const { return Impl.back(); } 287 const_reference back() const { return Impl.front(); } 288 289 iterator begin() { return Impl.rbegin(); } 290 iterator end() { return Impl.rend(); } 291 const_iterator begin() const { return Impl.rbegin(); } 292 const_iterator end() const { return Impl.rend(); } 293 reverse_iterator rbegin() { return Impl.begin(); } 294 reverse_iterator rend() { return Impl.end(); } 295 const_reverse_iterator rbegin() const { return Impl.begin(); } 296 const_reverse_iterator rend() const { return Impl.end(); } 297 298 CFGElement operator[](size_t i) const { 299 assert(i < Impl.size()); 300 return Impl[Impl.size() - 1 - i]; 301 } 302 303 size_t size() const { return Impl.size(); } 304 bool empty() const { return Impl.empty(); } 305 }; 306 307 /// Stmts - The set of statements in the basic block. 308 ElementList Elements; 309 310 /// Label - An (optional) label that prefixes the executable 311 /// statements in the block. When this variable is non-NULL, it is 312 /// either an instance of LabelStmt, SwitchCase or CXXCatchStmt. 313 Stmt *Label; 314 315 /// Terminator - The terminator for a basic block that 316 /// indicates the type of control-flow that occurs between a block 317 /// and its successors. 318 CFGTerminator Terminator; 319 320 /// LoopTarget - Some blocks are used to represent the "loop edge" to 321 /// the start of a loop from within the loop body. This Stmt* will be 322 /// refer to the loop statement for such blocks (and be null otherwise). 323 const Stmt *LoopTarget; 324 325 /// BlockID - A numerical ID assigned to a CFGBlock during construction 326 /// of the CFG. 327 unsigned BlockID; 328 329 /// Predecessors/Successors - Keep track of the predecessor / successor 330 /// CFG blocks. 331 typedef BumpVector<CFGBlock*> AdjacentBlocks; 332 AdjacentBlocks Preds; 333 AdjacentBlocks Succs; 334 335 /// NoReturn - This bit is set when the basic block contains a function call 336 /// or implicit destructor that is attributed as 'noreturn'. In that case, 337 /// control cannot technically ever proceed past this block. All such blocks 338 /// will have a single immediate successor: the exit block. This allows them 339 /// to be easily reached from the exit block and using this bit quickly 340 /// recognized without scanning the contents of the block. 341 /// 342 /// Optimization Note: This bit could be profitably folded with Terminator's 343 /// storage if the memory usage of CFGBlock becomes an issue. 344 unsigned HasNoReturnElement : 1; 345 346 /// Parent - The parent CFG that owns this CFGBlock. 347 CFG *Parent; 348 349public: 350 explicit CFGBlock(unsigned blockid, BumpVectorContext &C, CFG *parent) 351 : Elements(C), Label(NULL), Terminator(NULL), LoopTarget(NULL), 352 BlockID(blockid), Preds(C, 1), Succs(C, 1), HasNoReturnElement(false), 353 Parent(parent) {} 354 ~CFGBlock() {} 355 356 // Statement iterators 357 typedef ElementList::iterator iterator; 358 typedef ElementList::const_iterator const_iterator; 359 typedef ElementList::reverse_iterator reverse_iterator; 360 typedef ElementList::const_reverse_iterator const_reverse_iterator; 361 362 CFGElement front() const { return Elements.front(); } 363 CFGElement back() const { return Elements.back(); } 364 365 iterator begin() { return Elements.begin(); } 366 iterator end() { return Elements.end(); } 367 const_iterator begin() const { return Elements.begin(); } 368 const_iterator end() const { return Elements.end(); } 369 370 reverse_iterator rbegin() { return Elements.rbegin(); } 371 reverse_iterator rend() { return Elements.rend(); } 372 const_reverse_iterator rbegin() const { return Elements.rbegin(); } 373 const_reverse_iterator rend() const { return Elements.rend(); } 374 375 unsigned size() const { return Elements.size(); } 376 bool empty() const { return Elements.empty(); } 377 378 CFGElement operator[](size_t i) const { return Elements[i]; } 379 380 // CFG iterators 381 typedef AdjacentBlocks::iterator pred_iterator; 382 typedef AdjacentBlocks::const_iterator const_pred_iterator; 383 typedef AdjacentBlocks::reverse_iterator pred_reverse_iterator; 384 typedef AdjacentBlocks::const_reverse_iterator const_pred_reverse_iterator; 385 386 typedef AdjacentBlocks::iterator succ_iterator; 387 typedef AdjacentBlocks::const_iterator const_succ_iterator; 388 typedef AdjacentBlocks::reverse_iterator succ_reverse_iterator; 389 typedef AdjacentBlocks::const_reverse_iterator const_succ_reverse_iterator; 390 391 pred_iterator pred_begin() { return Preds.begin(); } 392 pred_iterator pred_end() { return Preds.end(); } 393 const_pred_iterator pred_begin() const { return Preds.begin(); } 394 const_pred_iterator pred_end() const { return Preds.end(); } 395 396 pred_reverse_iterator pred_rbegin() { return Preds.rbegin(); } 397 pred_reverse_iterator pred_rend() { return Preds.rend(); } 398 const_pred_reverse_iterator pred_rbegin() const { return Preds.rbegin(); } 399 const_pred_reverse_iterator pred_rend() const { return Preds.rend(); } 400 401 succ_iterator succ_begin() { return Succs.begin(); } 402 succ_iterator succ_end() { return Succs.end(); } 403 const_succ_iterator succ_begin() const { return Succs.begin(); } 404 const_succ_iterator succ_end() const { return Succs.end(); } 405 406 succ_reverse_iterator succ_rbegin() { return Succs.rbegin(); } 407 succ_reverse_iterator succ_rend() { return Succs.rend(); } 408 const_succ_reverse_iterator succ_rbegin() const { return Succs.rbegin(); } 409 const_succ_reverse_iterator succ_rend() const { return Succs.rend(); } 410 411 unsigned succ_size() const { return Succs.size(); } 412 bool succ_empty() const { return Succs.empty(); } 413 414 unsigned pred_size() const { return Preds.size(); } 415 bool pred_empty() const { return Preds.empty(); } 416 417 418 class FilterOptions { 419 public: 420 FilterOptions() { 421 IgnoreDefaultsWithCoveredEnums = 0; 422 } 423 424 unsigned IgnoreDefaultsWithCoveredEnums : 1; 425 }; 426 427 static bool FilterEdge(const FilterOptions &F, const CFGBlock *Src, 428 const CFGBlock *Dst); 429 430 template <typename IMPL, bool IsPred> 431 class FilteredCFGBlockIterator { 432 private: 433 IMPL I, E; 434 const FilterOptions F; 435 const CFGBlock *From; 436 public: 437 explicit FilteredCFGBlockIterator(const IMPL &i, const IMPL &e, 438 const CFGBlock *from, 439 const FilterOptions &f) 440 : I(i), E(e), F(f), From(from) {} 441 442 bool hasMore() const { return I != E; } 443 444 FilteredCFGBlockIterator &operator++() { 445 do { ++I; } while (hasMore() && Filter(*I)); 446 return *this; 447 } 448 449 const CFGBlock *operator*() const { return *I; } 450 private: 451 bool Filter(const CFGBlock *To) { 452 return IsPred ? FilterEdge(F, To, From) : FilterEdge(F, From, To); 453 } 454 }; 455 456 typedef FilteredCFGBlockIterator<const_pred_iterator, true> 457 filtered_pred_iterator; 458 459 typedef FilteredCFGBlockIterator<const_succ_iterator, false> 460 filtered_succ_iterator; 461 462 filtered_pred_iterator filtered_pred_start_end(const FilterOptions &f) const { 463 return filtered_pred_iterator(pred_begin(), pred_end(), this, f); 464 } 465 466 filtered_succ_iterator filtered_succ_start_end(const FilterOptions &f) const { 467 return filtered_succ_iterator(succ_begin(), succ_end(), this, f); 468 } 469 470 // Manipulation of block contents 471 472 void setTerminator(Stmt *Statement) { Terminator = Statement; } 473 void setLabel(Stmt *Statement) { Label = Statement; } 474 void setLoopTarget(const Stmt *loopTarget) { LoopTarget = loopTarget; } 475 void setHasNoReturnElement() { HasNoReturnElement = true; } 476 477 CFGTerminator getTerminator() { return Terminator; } 478 const CFGTerminator getTerminator() const { return Terminator; } 479 480 Stmt *getTerminatorCondition(); 481 482 const Stmt *getTerminatorCondition() const { 483 return const_cast<CFGBlock*>(this)->getTerminatorCondition(); 484 } 485 486 const Stmt *getLoopTarget() const { return LoopTarget; } 487 488 Stmt *getLabel() { return Label; } 489 const Stmt *getLabel() const { return Label; } 490 491 bool hasNoReturnElement() const { return HasNoReturnElement; } 492 493 unsigned getBlockID() const { return BlockID; } 494 495 CFG *getParent() const { return Parent; } 496 497 void dump(const CFG *cfg, const LangOptions &LO, bool ShowColors = false) const; 498 void print(raw_ostream &OS, const CFG* cfg, const LangOptions &LO, 499 bool ShowColors) const; 500 void printTerminator(raw_ostream &OS, const LangOptions &LO) const; 501 502 void addSuccessor(CFGBlock *Block, BumpVectorContext &C) { 503 if (Block) 504 Block->Preds.push_back(this, C); 505 Succs.push_back(Block, C); 506 } 507 508 void appendStmt(Stmt *statement, BumpVectorContext &C) { 509 Elements.push_back(CFGStmt(statement), C); 510 } 511 512 void appendInitializer(CXXCtorInitializer *initializer, 513 BumpVectorContext &C) { 514 Elements.push_back(CFGInitializer(initializer), C); 515 } 516 517 void appendBaseDtor(const CXXBaseSpecifier *BS, BumpVectorContext &C) { 518 Elements.push_back(CFGBaseDtor(BS), C); 519 } 520 521 void appendMemberDtor(FieldDecl *FD, BumpVectorContext &C) { 522 Elements.push_back(CFGMemberDtor(FD), C); 523 } 524 525 void appendTemporaryDtor(CXXBindTemporaryExpr *E, BumpVectorContext &C) { 526 Elements.push_back(CFGTemporaryDtor(E), C); 527 } 528 529 void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C) { 530 Elements.push_back(CFGAutomaticObjDtor(VD, S), C); 531 } 532 533 // Destructors must be inserted in reversed order. So insertion is in two 534 // steps. First we prepare space for some number of elements, then we insert 535 // the elements beginning at the last position in prepared space. 536 iterator beginAutomaticObjDtorsInsert(iterator I, size_t Cnt, 537 BumpVectorContext &C) { 538 return iterator(Elements.insert(I.base(), Cnt, CFGElement(), C)); 539 } 540 iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S) { 541 *I = CFGAutomaticObjDtor(VD, S); 542 return ++I; 543 } 544}; 545 546/// CFG - Represents a source-level, intra-procedural CFG that represents the 547/// control-flow of a Stmt. The Stmt can represent an entire function body, 548/// or a single expression. A CFG will always contain one empty block that 549/// represents the Exit point of the CFG. A CFG will also contain a designated 550/// Entry block. The CFG solely represents control-flow; it consists of 551/// CFGBlocks which are simply containers of Stmt*'s in the AST the CFG 552/// was constructed from. 553class CFG { 554public: 555 //===--------------------------------------------------------------------===// 556 // CFG Construction & Manipulation. 557 //===--------------------------------------------------------------------===// 558 559 class BuildOptions { 560 std::bitset<Stmt::lastStmtConstant> alwaysAddMask; 561 public: 562 typedef llvm::DenseMap<const Stmt *, const CFGBlock*> ForcedBlkExprs; 563 ForcedBlkExprs **forcedBlkExprs; 564 565 bool PruneTriviallyFalseEdges; 566 bool AddEHEdges; 567 bool AddInitializers; 568 bool AddImplicitDtors; 569 bool AddTemporaryDtors; 570 571 bool alwaysAdd(const Stmt *stmt) const { 572 return alwaysAddMask[stmt->getStmtClass()]; 573 } 574 575 BuildOptions &setAlwaysAdd(Stmt::StmtClass stmtClass, bool val = true) { 576 alwaysAddMask[stmtClass] = val; 577 return *this; 578 } 579 580 BuildOptions &setAllAlwaysAdd() { 581 alwaysAddMask.set(); 582 return *this; 583 } 584 585 BuildOptions() 586 : forcedBlkExprs(0), PruneTriviallyFalseEdges(true) 587 ,AddEHEdges(false) 588 ,AddInitializers(false) 589 ,AddImplicitDtors(false) 590 ,AddTemporaryDtors(false) {} 591 }; 592 593 /// \brief Provides a custom implementation of the iterator class to have the 594 /// same interface as Function::iterator - iterator returns CFGBlock 595 /// (not a pointer to CFGBlock). 596 class graph_iterator { 597 public: 598 typedef const CFGBlock value_type; 599 typedef value_type& reference; 600 typedef value_type* pointer; 601 typedef BumpVector<CFGBlock*>::iterator ImplTy; 602 603 graph_iterator(const ImplTy &i) : I(i) {} 604 605 bool operator==(const graph_iterator &X) const { return I == X.I; } 606 bool operator!=(const graph_iterator &X) const { return I != X.I; } 607 608 reference operator*() const { return **I; } 609 pointer operator->() const { return *I; } 610 operator CFGBlock* () { return *I; } 611 612 graph_iterator &operator++() { ++I; return *this; } 613 graph_iterator &operator--() { --I; return *this; } 614 615 private: 616 ImplTy I; 617 }; 618 619 class const_graph_iterator { 620 public: 621 typedef const CFGBlock value_type; 622 typedef value_type& reference; 623 typedef value_type* pointer; 624 typedef BumpVector<CFGBlock*>::const_iterator ImplTy; 625 626 const_graph_iterator(const ImplTy &i) : I(i) {} 627 628 bool operator==(const const_graph_iterator &X) const { return I == X.I; } 629 bool operator!=(const const_graph_iterator &X) const { return I != X.I; } 630 631 reference operator*() const { return **I; } 632 pointer operator->() const { return *I; } 633 operator CFGBlock* () const { return *I; } 634 635 const_graph_iterator &operator++() { ++I; return *this; } 636 const_graph_iterator &operator--() { --I; return *this; } 637 638 private: 639 ImplTy I; 640 }; 641 642 /// buildCFG - Builds a CFG from an AST. The responsibility to free the 643 /// constructed CFG belongs to the caller. 644 static CFG* buildCFG(const Decl *D, Stmt *AST, ASTContext *C, 645 const BuildOptions &BO); 646 647 /// createBlock - Create a new block in the CFG. The CFG owns the block; 648 /// the caller should not directly free it. 649 CFGBlock *createBlock(); 650 651 /// setEntry - Set the entry block of the CFG. This is typically used 652 /// only during CFG construction. Most CFG clients expect that the 653 /// entry block has no predecessors and contains no statements. 654 void setEntry(CFGBlock *B) { Entry = B; } 655 656 /// setIndirectGotoBlock - Set the block used for indirect goto jumps. 657 /// This is typically used only during CFG construction. 658 void setIndirectGotoBlock(CFGBlock *B) { IndirectGotoBlock = B; } 659 660 //===--------------------------------------------------------------------===// 661 // Block Iterators 662 //===--------------------------------------------------------------------===// 663 664 typedef BumpVector<CFGBlock*> CFGBlockListTy; 665 typedef CFGBlockListTy::iterator iterator; 666 typedef CFGBlockListTy::const_iterator const_iterator; 667 typedef std::reverse_iterator<iterator> reverse_iterator; 668 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 669 670 CFGBlock & front() { return *Blocks.front(); } 671 CFGBlock & back() { return *Blocks.back(); } 672 673 iterator begin() { return Blocks.begin(); } 674 iterator end() { return Blocks.end(); } 675 const_iterator begin() const { return Blocks.begin(); } 676 const_iterator end() const { return Blocks.end(); } 677 678 graph_iterator nodes_begin() { return graph_iterator(Blocks.begin()); } 679 graph_iterator nodes_end() { return graph_iterator(Blocks.end()); } 680 const_graph_iterator nodes_begin() const { 681 return const_graph_iterator(Blocks.begin()); 682 } 683 const_graph_iterator nodes_end() const { 684 return const_graph_iterator(Blocks.end()); 685 } 686 687 reverse_iterator rbegin() { return Blocks.rbegin(); } 688 reverse_iterator rend() { return Blocks.rend(); } 689 const_reverse_iterator rbegin() const { return Blocks.rbegin(); } 690 const_reverse_iterator rend() const { return Blocks.rend(); } 691 692 CFGBlock & getEntry() { return *Entry; } 693 const CFGBlock & getEntry() const { return *Entry; } 694 CFGBlock & getExit() { return *Exit; } 695 const CFGBlock & getExit() const { return *Exit; } 696 697 CFGBlock * getIndirectGotoBlock() { return IndirectGotoBlock; } 698 const CFGBlock * getIndirectGotoBlock() const { return IndirectGotoBlock; } 699 700 typedef std::vector<const CFGBlock*>::const_iterator try_block_iterator; 701 try_block_iterator try_blocks_begin() const { 702 return TryDispatchBlocks.begin(); 703 } 704 try_block_iterator try_blocks_end() const { 705 return TryDispatchBlocks.end(); 706 } 707 708 void addTryDispatchBlock(const CFGBlock *block) { 709 TryDispatchBlocks.push_back(block); 710 } 711 712 //===--------------------------------------------------------------------===// 713 // Member templates useful for various batch operations over CFGs. 714 //===--------------------------------------------------------------------===// 715 716 template <typename CALLBACK> 717 void VisitBlockStmts(CALLBACK& O) const { 718 for (const_iterator I=begin(), E=end(); I != E; ++I) 719 for (CFGBlock::const_iterator BI=(*I)->begin(), BE=(*I)->end(); 720 BI != BE; ++BI) { 721 if (const CFGStmt *stmt = BI->getAs<CFGStmt>()) 722 O(const_cast<Stmt*>(stmt->getStmt())); 723 } 724 } 725 726 //===--------------------------------------------------------------------===// 727 // CFG Introspection. 728 //===--------------------------------------------------------------------===// 729 730 struct BlkExprNumTy { 731 const signed Idx; 732 explicit BlkExprNumTy(signed idx) : Idx(idx) {} 733 explicit BlkExprNumTy() : Idx(-1) {} 734 operator bool() const { return Idx >= 0; } 735 operator unsigned() const { assert(Idx >=0); return (unsigned) Idx; } 736 }; 737 738 bool isBlkExpr(const Stmt *S) { return getBlkExprNum(S); } 739 bool isBlkExpr(const Stmt *S) const { 740 return const_cast<CFG*>(this)->isBlkExpr(S); 741 } 742 BlkExprNumTy getBlkExprNum(const Stmt *S); 743 unsigned getNumBlkExprs(); 744 745 /// getNumBlockIDs - Returns the total number of BlockIDs allocated (which 746 /// start at 0). 747 unsigned getNumBlockIDs() const { return NumBlockIDs; } 748 749 /// size - Return the total number of CFGBlocks within the CFG 750 /// This is simply a renaming of the getNumBlockIDs(). This is necessary 751 /// because the dominator implementation needs such an interface. 752 unsigned size() const { return NumBlockIDs; } 753 754 //===--------------------------------------------------------------------===// 755 // CFG Debugging: Pretty-Printing and Visualization. 756 //===--------------------------------------------------------------------===// 757 758 void viewCFG(const LangOptions &LO) const; 759 void print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const; 760 void dump(const LangOptions &LO, bool ShowColors) const; 761 762 //===--------------------------------------------------------------------===// 763 // Internal: constructors and data. 764 //===--------------------------------------------------------------------===// 765 766 CFG() : Entry(NULL), Exit(NULL), IndirectGotoBlock(NULL), NumBlockIDs(0), 767 BlkExprMap(NULL), Blocks(BlkBVC, 10) {} 768 769 ~CFG(); 770 771 llvm::BumpPtrAllocator& getAllocator() { 772 return BlkBVC.getAllocator(); 773 } 774 775 BumpVectorContext &getBumpVectorContext() { 776 return BlkBVC; 777 } 778 779private: 780 CFGBlock *Entry; 781 CFGBlock *Exit; 782 CFGBlock* IndirectGotoBlock; // Special block to contain collective dispatch 783 // for indirect gotos 784 unsigned NumBlockIDs; 785 786 // BlkExprMap - An opaque pointer to prevent inclusion of DenseMap.h. 787 // It represents a map from Expr* to integers to record the set of 788 // block-level expressions and their "statement number" in the CFG. 789 void * BlkExprMap; 790 791 BumpVectorContext BlkBVC; 792 793 CFGBlockListTy Blocks; 794 795 /// C++ 'try' statements are modeled with an indirect dispatch block. 796 /// This is the collection of such blocks present in the CFG. 797 std::vector<const CFGBlock *> TryDispatchBlocks; 798 799}; 800} // end namespace clang 801 802//===----------------------------------------------------------------------===// 803// GraphTraits specializations for CFG basic block graphs (source-level CFGs) 804//===----------------------------------------------------------------------===// 805 806namespace llvm { 807 808/// Implement simplify_type for CFGTerminator, so that we can dyn_cast from 809/// CFGTerminator to a specific Stmt class. 810template <> struct simplify_type<const ::clang::CFGTerminator> { 811 typedef const ::clang::Stmt *SimpleType; 812 static SimpleType getSimplifiedValue(const ::clang::CFGTerminator &Val) { 813 return Val.getStmt(); 814 } 815}; 816 817template <> struct simplify_type< ::clang::CFGTerminator> { 818 typedef ::clang::Stmt *SimpleType; 819 static SimpleType getSimplifiedValue(const ::clang::CFGTerminator &Val) { 820 return const_cast<SimpleType>(Val.getStmt()); 821 } 822}; 823 824// Traits for: CFGBlock 825 826template <> struct GraphTraits< ::clang::CFGBlock *> { 827 typedef ::clang::CFGBlock NodeType; 828 typedef ::clang::CFGBlock::succ_iterator ChildIteratorType; 829 830 static NodeType* getEntryNode(::clang::CFGBlock *BB) 831 { return BB; } 832 833 static inline ChildIteratorType child_begin(NodeType* N) 834 { return N->succ_begin(); } 835 836 static inline ChildIteratorType child_end(NodeType* N) 837 { return N->succ_end(); } 838}; 839 840template <> struct GraphTraits< const ::clang::CFGBlock *> { 841 typedef const ::clang::CFGBlock NodeType; 842 typedef ::clang::CFGBlock::const_succ_iterator ChildIteratorType; 843 844 static NodeType* getEntryNode(const clang::CFGBlock *BB) 845 { return BB; } 846 847 static inline ChildIteratorType child_begin(NodeType* N) 848 { return N->succ_begin(); } 849 850 static inline ChildIteratorType child_end(NodeType* N) 851 { return N->succ_end(); } 852}; 853 854template <> struct GraphTraits<Inverse< ::clang::CFGBlock*> > { 855 typedef ::clang::CFGBlock NodeType; 856 typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType; 857 858 static NodeType *getEntryNode(Inverse< ::clang::CFGBlock*> G) 859 { return G.Graph; } 860 861 static inline ChildIteratorType child_begin(NodeType* N) 862 { return N->pred_begin(); } 863 864 static inline ChildIteratorType child_end(NodeType* N) 865 { return N->pred_end(); } 866}; 867 868template <> struct GraphTraits<Inverse<const ::clang::CFGBlock*> > { 869 typedef const ::clang::CFGBlock NodeType; 870 typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType; 871 872 static NodeType *getEntryNode(Inverse<const ::clang::CFGBlock*> G) 873 { return G.Graph; } 874 875 static inline ChildIteratorType child_begin(NodeType* N) 876 { return N->pred_begin(); } 877 878 static inline ChildIteratorType child_end(NodeType* N) 879 { return N->pred_end(); } 880}; 881 882// Traits for: CFG 883 884template <> struct GraphTraits< ::clang::CFG* > 885 : public GraphTraits< ::clang::CFGBlock *> { 886 887 typedef ::clang::CFG::graph_iterator nodes_iterator; 888 889 static NodeType *getEntryNode(::clang::CFG* F) { return &F->getEntry(); } 890 static nodes_iterator nodes_begin(::clang::CFG* F) { return F->nodes_begin();} 891 static nodes_iterator nodes_end(::clang::CFG* F) { return F->nodes_end(); } 892 static unsigned size(::clang::CFG* F) { return F->size(); } 893}; 894 895template <> struct GraphTraits<const ::clang::CFG* > 896 : public GraphTraits<const ::clang::CFGBlock *> { 897 898 typedef ::clang::CFG::const_graph_iterator nodes_iterator; 899 900 static NodeType *getEntryNode( const ::clang::CFG* F) { 901 return &F->getEntry(); 902 } 903 static nodes_iterator nodes_begin( const ::clang::CFG* F) { 904 return F->nodes_begin(); 905 } 906 static nodes_iterator nodes_end( const ::clang::CFG* F) { 907 return F->nodes_end(); 908 } 909 static unsigned size(const ::clang::CFG* F) { 910 return F->size(); 911 } 912}; 913 914template <> struct GraphTraits<Inverse< ::clang::CFG*> > 915 : public GraphTraits<Inverse< ::clang::CFGBlock*> > { 916 917 typedef ::clang::CFG::graph_iterator nodes_iterator; 918 919 static NodeType *getEntryNode( ::clang::CFG* F) { return &F->getExit(); } 920 static nodes_iterator nodes_begin( ::clang::CFG* F) {return F->nodes_begin();} 921 static nodes_iterator nodes_end( ::clang::CFG* F) { return F->nodes_end(); } 922}; 923 924template <> struct GraphTraits<Inverse<const ::clang::CFG*> > 925 : public GraphTraits<Inverse<const ::clang::CFGBlock*> > { 926 927 typedef ::clang::CFG::const_graph_iterator nodes_iterator; 928 929 static NodeType *getEntryNode(const ::clang::CFG* F) { return &F->getExit(); } 930 static nodes_iterator nodes_begin(const ::clang::CFG* F) { 931 return F->nodes_begin(); 932 } 933 static nodes_iterator nodes_end(const ::clang::CFG* F) { 934 return F->nodes_end(); 935 } 936}; 937} // end llvm namespace 938#endif 939