CFG.h revision 02f34c5003b2c5067675f89ffce0a84c28faf722
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 "llvm/ADT/BitVector.h" 25#include "clang/AST/Stmt.h" 26#include "clang/Analysis/Support/BumpVector.h" 27#include "clang/Basic/SourceLocation.h" 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 static bool classof(const CFGElement *E) { return true; } 93}; 94 95class CFGStmt : public CFGElement { 96public: 97 CFGStmt(Stmt *S) : CFGElement(Statement, S) {} 98 99 const Stmt *getStmt() const { 100 return static_cast<const Stmt *>(Data1.getPointer()); 101 } 102 103 static bool classof(const CFGElement *E) { 104 return E->getKind() == Statement; 105 } 106}; 107 108/// CFGInitializer - Represents C++ base or member initializer from 109/// constructor's initialization list. 110class CFGInitializer : public CFGElement { 111public: 112 CFGInitializer(CXXCtorInitializer *initializer) 113 : CFGElement(Initializer, initializer) {} 114 115 CXXCtorInitializer* getInitializer() const { 116 return static_cast<CXXCtorInitializer*>(Data1.getPointer()); 117 } 118 119 static bool classof(const CFGElement *E) { 120 return E->getKind() == Initializer; 121 } 122}; 123 124/// CFGImplicitDtor - Represents C++ object destructor implicitly generated 125/// by compiler on various occasions. 126class CFGImplicitDtor : public CFGElement { 127protected: 128 CFGImplicitDtor(Kind kind, const void *data1, const void *data2 = 0) 129 : CFGElement(kind, data1, data2) { 130 assert(kind >= DTOR_BEGIN && kind <= DTOR_END); 131 } 132 133public: 134 const CXXDestructorDecl *getDestructorDecl(ASTContext &astContext) const; 135 bool isNoReturn(ASTContext &astContext) const; 136 137 static bool classof(const CFGElement *E) { 138 Kind kind = E->getKind(); 139 return kind >= DTOR_BEGIN && kind <= DTOR_END; 140 } 141}; 142 143/// CFGAutomaticObjDtor - Represents C++ object destructor implicitly generated 144/// for automatic object or temporary bound to const reference at the point 145/// of leaving its local scope. 146class CFGAutomaticObjDtor: public CFGImplicitDtor { 147public: 148 CFGAutomaticObjDtor(const VarDecl *var, const Stmt *stmt) 149 : CFGImplicitDtor(AutomaticObjectDtor, var, stmt) {} 150 151 const VarDecl *getVarDecl() const { 152 return static_cast<VarDecl*>(Data1.getPointer()); 153 } 154 155 // Get statement end of which triggered the destructor call. 156 const Stmt *getTriggerStmt() const { 157 return static_cast<Stmt*>(Data2.getPointer()); 158 } 159 160 static bool classof(const CFGElement *elem) { 161 return elem->getKind() == AutomaticObjectDtor; 162 } 163}; 164 165/// CFGBaseDtor - Represents C++ object destructor implicitly generated for 166/// base object in destructor. 167class CFGBaseDtor : public CFGImplicitDtor { 168public: 169 CFGBaseDtor(const CXXBaseSpecifier *base) 170 : CFGImplicitDtor(BaseDtor, base) {} 171 172 const CXXBaseSpecifier *getBaseSpecifier() const { 173 return static_cast<const CXXBaseSpecifier*>(Data1.getPointer()); 174 } 175 176 static bool classof(const CFGElement *E) { 177 return E->getKind() == BaseDtor; 178 } 179}; 180 181/// CFGMemberDtor - Represents C++ object destructor implicitly generated for 182/// member object in destructor. 183class CFGMemberDtor : public CFGImplicitDtor { 184public: 185 CFGMemberDtor(const FieldDecl *field) 186 : CFGImplicitDtor(MemberDtor, field, 0) {} 187 188 const FieldDecl *getFieldDecl() const { 189 return static_cast<const FieldDecl*>(Data1.getPointer()); 190 } 191 192 static bool classof(const CFGElement *E) { 193 return E->getKind() == MemberDtor; 194 } 195}; 196 197/// CFGTemporaryDtor - Represents C++ object destructor implicitly generated 198/// at the end of full expression for temporary object. 199class CFGTemporaryDtor : public CFGImplicitDtor { 200public: 201 CFGTemporaryDtor(CXXBindTemporaryExpr *expr) 202 : CFGImplicitDtor(TemporaryDtor, expr, 0) {} 203 204 const CXXBindTemporaryExpr *getBindTemporaryExpr() const { 205 return static_cast<const CXXBindTemporaryExpr *>(Data1.getPointer()); 206 } 207 208 static bool classof(const CFGElement *E) { 209 return E->getKind() == TemporaryDtor; 210 } 211}; 212 213/// CFGTerminator - Represents CFGBlock terminator statement. 214/// 215/// TemporaryDtorsBranch bit is set to true if the terminator marks a branch 216/// in control flow of destructors of temporaries. In this case terminator 217/// statement is the same statement that branches control flow in evaluation 218/// of matching full expression. 219class CFGTerminator { 220 llvm::PointerIntPair<Stmt *, 1> Data; 221public: 222 CFGTerminator() {} 223 CFGTerminator(Stmt *S, bool TemporaryDtorsBranch = false) 224 : Data(S, TemporaryDtorsBranch) {} 225 226 Stmt *getStmt() { return Data.getPointer(); } 227 const Stmt *getStmt() const { return Data.getPointer(); } 228 229 bool isTemporaryDtorsBranch() const { return Data.getInt(); } 230 231 operator Stmt *() { return getStmt(); } 232 operator const Stmt *() const { return getStmt(); } 233 234 Stmt *operator->() { return getStmt(); } 235 const Stmt *operator->() const { return getStmt(); } 236 237 Stmt &operator*() { return *getStmt(); } 238 const Stmt &operator*() const { return *getStmt(); } 239 240 operator bool() const { return getStmt(); } 241}; 242 243/// CFGBlock - Represents a single basic block in a source-level CFG. 244/// It consists of: 245/// 246/// (1) A set of statements/expressions (which may contain subexpressions). 247/// (2) A "terminator" statement (not in the set of statements). 248/// (3) A list of successors and predecessors. 249/// 250/// Terminator: The terminator represents the type of control-flow that occurs 251/// at the end of the basic block. The terminator is a Stmt* referring to an 252/// AST node that has control-flow: if-statements, breaks, loops, etc. 253/// If the control-flow is conditional, the condition expression will appear 254/// within the set of statements in the block (usually the last statement). 255/// 256/// Predecessors: the order in the set of predecessors is arbitrary. 257/// 258/// Successors: the order in the set of successors is NOT arbitrary. We 259/// currently have the following orderings based on the terminator: 260/// 261/// Terminator Successor Ordering 262/// ----------------------------------------------------- 263/// if Then Block; Else Block 264/// ? operator LHS expression; RHS expression 265/// &&, || expression that uses result of && or ||, RHS 266/// 267/// But note that any of that may be NULL in case of optimized-out edges. 268/// 269class CFGBlock { 270 class ElementList { 271 typedef BumpVector<CFGElement> ImplTy; 272 ImplTy Impl; 273 public: 274 ElementList(BumpVectorContext &C) : Impl(C, 4) {} 275 276 typedef std::reverse_iterator<ImplTy::iterator> iterator; 277 typedef std::reverse_iterator<ImplTy::const_iterator> const_iterator; 278 typedef ImplTy::iterator reverse_iterator; 279 typedef ImplTy::const_iterator const_reverse_iterator; 280 281 void push_back(CFGElement e, BumpVectorContext &C) { Impl.push_back(e, C); } 282 reverse_iterator insert(reverse_iterator I, size_t Cnt, CFGElement E, 283 BumpVectorContext &C) { 284 return Impl.insert(I, Cnt, E, C); 285 } 286 287 CFGElement front() const { return Impl.back(); } 288 CFGElement back() const { return Impl.front(); } 289 290 iterator begin() { return Impl.rbegin(); } 291 iterator end() { return Impl.rend(); } 292 const_iterator begin() const { return Impl.rbegin(); } 293 const_iterator end() const { return Impl.rend(); } 294 reverse_iterator rbegin() { return Impl.begin(); } 295 reverse_iterator rend() { return Impl.end(); } 296 const_reverse_iterator rbegin() const { return Impl.begin(); } 297 const_reverse_iterator rend() const { return Impl.end(); } 298 299 CFGElement operator[](size_t i) const { 300 assert(i < Impl.size()); 301 return Impl[Impl.size() - 1 - i]; 302 } 303 304 size_t size() const { return Impl.size(); } 305 bool empty() const { return Impl.empty(); } 306 }; 307 308 /// Stmts - The set of statements in the basic block. 309 ElementList Elements; 310 311 /// Label - An (optional) label that prefixes the executable 312 /// statements in the block. When this variable is non-NULL, it is 313 /// either an instance of LabelStmt, SwitchCase or CXXCatchStmt. 314 Stmt *Label; 315 316 /// Terminator - The terminator for a basic block that 317 /// indicates the type of control-flow that occurs between a block 318 /// and its successors. 319 CFGTerminator Terminator; 320 321 /// LoopTarget - Some blocks are used to represent the "loop edge" to 322 /// the start of a loop from within the loop body. This Stmt* will be 323 /// refer to the loop statement for such blocks (and be null otherwise). 324 const Stmt *LoopTarget; 325 326 /// BlockID - A numerical ID assigned to a CFGBlock during construction 327 /// of the CFG. 328 unsigned BlockID; 329 330 /// Predecessors/Successors - Keep track of the predecessor / successor 331 /// CFG blocks. 332 typedef BumpVector<CFGBlock*> AdjacentBlocks; 333 AdjacentBlocks Preds; 334 AdjacentBlocks Succs; 335 336 /// NoReturn - This bit is set when the basic block contains a function call 337 /// or implicit destructor that is attributed as 'noreturn'. In that case, 338 /// control cannot technically ever proceed past this block. All such blocks 339 /// will have a single immediate successor: the exit block. This allows them 340 /// to be easily reached from the exit block and using this bit quickly 341 /// recognized without scanning the contents of the block. 342 /// 343 /// Optimization Note: This bit could be profitably folded with Terminator's 344 /// storage if the memory usage of CFGBlock becomes an issue. 345 unsigned HasNoReturnElement : 1; 346 347 /// Parent - The parent CFG that owns this CFGBlock. 348 CFG *Parent; 349 350public: 351 explicit CFGBlock(unsigned blockid, BumpVectorContext &C, CFG *parent) 352 : Elements(C), Label(NULL), Terminator(NULL), LoopTarget(NULL), 353 BlockID(blockid), Preds(C, 1), Succs(C, 1), HasNoReturnElement(false), 354 Parent(parent) {} 355 ~CFGBlock() {} 356 357 // Statement iterators 358 typedef ElementList::iterator iterator; 359 typedef ElementList::const_iterator const_iterator; 360 typedef ElementList::reverse_iterator reverse_iterator; 361 typedef ElementList::const_reverse_iterator const_reverse_iterator; 362 363 CFGElement front() const { return Elements.front(); } 364 CFGElement back() const { return Elements.back(); } 365 366 iterator begin() { return Elements.begin(); } 367 iterator end() { return Elements.end(); } 368 const_iterator begin() const { return Elements.begin(); } 369 const_iterator end() const { return Elements.end(); } 370 371 reverse_iterator rbegin() { return Elements.rbegin(); } 372 reverse_iterator rend() { return Elements.rend(); } 373 const_reverse_iterator rbegin() const { return Elements.rbegin(); } 374 const_reverse_iterator rend() const { return Elements.rend(); } 375 376 unsigned size() const { return Elements.size(); } 377 bool empty() const { return Elements.empty(); } 378 379 CFGElement operator[](size_t i) const { return Elements[i]; } 380 381 // CFG iterators 382 typedef AdjacentBlocks::iterator pred_iterator; 383 typedef AdjacentBlocks::const_iterator const_pred_iterator; 384 typedef AdjacentBlocks::reverse_iterator pred_reverse_iterator; 385 typedef AdjacentBlocks::const_reverse_iterator const_pred_reverse_iterator; 386 387 typedef AdjacentBlocks::iterator succ_iterator; 388 typedef AdjacentBlocks::const_iterator const_succ_iterator; 389 typedef AdjacentBlocks::reverse_iterator succ_reverse_iterator; 390 typedef AdjacentBlocks::const_reverse_iterator const_succ_reverse_iterator; 391 392 pred_iterator pred_begin() { return Preds.begin(); } 393 pred_iterator pred_end() { return Preds.end(); } 394 const_pred_iterator pred_begin() const { return Preds.begin(); } 395 const_pred_iterator pred_end() const { return Preds.end(); } 396 397 pred_reverse_iterator pred_rbegin() { return Preds.rbegin(); } 398 pred_reverse_iterator pred_rend() { return Preds.rend(); } 399 const_pred_reverse_iterator pred_rbegin() const { return Preds.rbegin(); } 400 const_pred_reverse_iterator pred_rend() const { return Preds.rend(); } 401 402 succ_iterator succ_begin() { return Succs.begin(); } 403 succ_iterator succ_end() { return Succs.end(); } 404 const_succ_iterator succ_begin() const { return Succs.begin(); } 405 const_succ_iterator succ_end() const { return Succs.end(); } 406 407 succ_reverse_iterator succ_rbegin() { return Succs.rbegin(); } 408 succ_reverse_iterator succ_rend() { return Succs.rend(); } 409 const_succ_reverse_iterator succ_rbegin() const { return Succs.rbegin(); } 410 const_succ_reverse_iterator succ_rend() const { return Succs.rend(); } 411 412 unsigned succ_size() const { return Succs.size(); } 413 bool succ_empty() const { return Succs.empty(); } 414 415 unsigned pred_size() const { return Preds.size(); } 416 bool pred_empty() const { return Preds.empty(); } 417 418 419 class FilterOptions { 420 public: 421 FilterOptions() { 422 IgnoreDefaultsWithCoveredEnums = 0; 423 } 424 425 unsigned IgnoreDefaultsWithCoveredEnums : 1; 426 }; 427 428 static bool FilterEdge(const FilterOptions &F, const CFGBlock *Src, 429 const CFGBlock *Dst); 430 431 template <typename IMPL, bool IsPred> 432 class FilteredCFGBlockIterator { 433 private: 434 IMPL I, E; 435 const FilterOptions F; 436 const CFGBlock *From; 437 public: 438 explicit FilteredCFGBlockIterator(const IMPL &i, const IMPL &e, 439 const CFGBlock *from, 440 const FilterOptions &f) 441 : I(i), E(e), F(f), From(from) {} 442 443 bool hasMore() const { return I != E; } 444 445 FilteredCFGBlockIterator &operator++() { 446 do { ++I; } while (hasMore() && Filter(*I)); 447 return *this; 448 } 449 450 const CFGBlock *operator*() const { return *I; } 451 private: 452 bool Filter(const CFGBlock *To) { 453 return IsPred ? FilterEdge(F, To, From) : FilterEdge(F, From, To); 454 } 455 }; 456 457 typedef FilteredCFGBlockIterator<const_pred_iterator, true> 458 filtered_pred_iterator; 459 460 typedef FilteredCFGBlockIterator<const_succ_iterator, false> 461 filtered_succ_iterator; 462 463 filtered_pred_iterator filtered_pred_start_end(const FilterOptions &f) const { 464 return filtered_pred_iterator(pred_begin(), pred_end(), this, f); 465 } 466 467 filtered_succ_iterator filtered_succ_start_end(const FilterOptions &f) const { 468 return filtered_succ_iterator(succ_begin(), succ_end(), this, f); 469 } 470 471 // Manipulation of block contents 472 473 void setTerminator(Stmt *Statement) { Terminator = Statement; } 474 void setLabel(Stmt *Statement) { Label = Statement; } 475 void setLoopTarget(const Stmt *loopTarget) { LoopTarget = loopTarget; } 476 void setHasNoReturnElement() { HasNoReturnElement = true; } 477 478 CFGTerminator getTerminator() { return Terminator; } 479 const CFGTerminator getTerminator() const { return Terminator; } 480 481 Stmt *getTerminatorCondition(); 482 483 const Stmt *getTerminatorCondition() const { 484 return const_cast<CFGBlock*>(this)->getTerminatorCondition(); 485 } 486 487 const Stmt *getLoopTarget() const { return LoopTarget; } 488 489 Stmt *getLabel() { return Label; } 490 const Stmt *getLabel() const { return Label; } 491 492 bool hasNoReturnElement() const { return HasNoReturnElement; } 493 494 unsigned getBlockID() const { return BlockID; } 495 496 CFG *getParent() const { return Parent; } 497 498 void dump(const CFG *cfg, const LangOptions &LO) const; 499 void print(raw_ostream &OS, const CFG* cfg, const LangOptions &LO) 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 llvm::BitVector 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; 569 570 bool alwaysAdd(const Stmt *stmt) const { 571 return alwaysAddMask[stmt->getStmtClass()]; 572 } 573 574 BuildOptions &setAlwaysAdd(Stmt::StmtClass stmtClass, bool val = true) { 575 alwaysAddMask[stmtClass] = val; 576 return *this; 577 } 578 579 BuildOptions &setAllAlwaysAdd() { 580 alwaysAddMask.set(); 581 return *this; 582 } 583 584 BuildOptions() 585 : alwaysAddMask(Stmt::lastStmtConstant, false) 586 ,forcedBlkExprs(0), PruneTriviallyFalseEdges(true) 587 ,AddEHEdges(false) 588 ,AddInitializers(false) 589 ,AddImplicitDtors(false) {} 590 }; 591 592 /// \brief Provides a custom implementation of the iterator class to have the 593 /// same interface as Function::iterator - iterator returns CFGBlock 594 /// (not a pointer to CFGBlock). 595 class graph_iterator { 596 public: 597 typedef const CFGBlock value_type; 598 typedef value_type& reference; 599 typedef value_type* pointer; 600 typedef BumpVector<CFGBlock*>::iterator ImplTy; 601 602 graph_iterator(const ImplTy &i) : I(i) {} 603 604 bool operator==(const graph_iterator &X) const { return I == X.I; } 605 bool operator!=(const graph_iterator &X) const { return I != X.I; } 606 607 reference operator*() const { return **I; } 608 pointer operator->() const { return *I; } 609 operator CFGBlock* () { return *I; } 610 611 graph_iterator &operator++() { ++I; return *this; } 612 graph_iterator &operator--() { --I; return *this; } 613 614 private: 615 ImplTy I; 616 }; 617 618 class const_graph_iterator { 619 public: 620 typedef const CFGBlock value_type; 621 typedef value_type& reference; 622 typedef value_type* pointer; 623 typedef BumpVector<CFGBlock*>::const_iterator ImplTy; 624 625 const_graph_iterator(const ImplTy &i) : I(i) {} 626 627 bool operator==(const const_graph_iterator &X) const { return I == X.I; } 628 bool operator!=(const const_graph_iterator &X) const { return I != X.I; } 629 630 reference operator*() const { return **I; } 631 pointer operator->() const { return *I; } 632 operator CFGBlock* () const { return *I; } 633 634 const_graph_iterator &operator++() { ++I; return *this; } 635 const_graph_iterator &operator--() { --I; return *this; } 636 637 private: 638 ImplTy I; 639 }; 640 641 /// buildCFG - Builds a CFG from an AST. The responsibility to free the 642 /// constructed CFG belongs to the caller. 643 static CFG* buildCFG(const Decl *D, Stmt *AST, ASTContext *C, 644 const BuildOptions &BO); 645 646 /// createBlock - Create a new block in the CFG. The CFG owns the block; 647 /// the caller should not directly free it. 648 CFGBlock *createBlock(); 649 650 /// setEntry - Set the entry block of the CFG. This is typically used 651 /// only during CFG construction. Most CFG clients expect that the 652 /// entry block has no predecessors and contains no statements. 653 void setEntry(CFGBlock *B) { Entry = B; } 654 655 /// setIndirectGotoBlock - Set the block used for indirect goto jumps. 656 /// This is typically used only during CFG construction. 657 void setIndirectGotoBlock(CFGBlock *B) { IndirectGotoBlock = B; } 658 659 //===--------------------------------------------------------------------===// 660 // Block Iterators 661 //===--------------------------------------------------------------------===// 662 663 typedef BumpVector<CFGBlock*> CFGBlockListTy; 664 typedef CFGBlockListTy::iterator iterator; 665 typedef CFGBlockListTy::const_iterator const_iterator; 666 typedef std::reverse_iterator<iterator> reverse_iterator; 667 typedef std::reverse_iterator<const_iterator> const_reverse_iterator; 668 669 CFGBlock & front() { return *Blocks.front(); } 670 CFGBlock & back() { return *Blocks.back(); } 671 672 iterator begin() { return Blocks.begin(); } 673 iterator end() { return Blocks.end(); } 674 const_iterator begin() const { return Blocks.begin(); } 675 const_iterator end() const { return Blocks.end(); } 676 677 graph_iterator nodes_begin() { return graph_iterator(Blocks.begin()); } 678 graph_iterator nodes_end() { return graph_iterator(Blocks.end()); } 679 const_graph_iterator nodes_begin() const { 680 return const_graph_iterator(Blocks.begin()); 681 } 682 const_graph_iterator nodes_end() const { 683 return const_graph_iterator(Blocks.end()); 684 } 685 686 reverse_iterator rbegin() { return Blocks.rbegin(); } 687 reverse_iterator rend() { return Blocks.rend(); } 688 const_reverse_iterator rbegin() const { return Blocks.rbegin(); } 689 const_reverse_iterator rend() const { return Blocks.rend(); } 690 691 CFGBlock & getEntry() { return *Entry; } 692 const CFGBlock & getEntry() const { return *Entry; } 693 CFGBlock & getExit() { return *Exit; } 694 const CFGBlock & getExit() const { return *Exit; } 695 696 CFGBlock * getIndirectGotoBlock() { return IndirectGotoBlock; } 697 const CFGBlock * getIndirectGotoBlock() const { return IndirectGotoBlock; } 698 699 typedef std::vector<const CFGBlock*>::const_iterator try_block_iterator; 700 try_block_iterator try_blocks_begin() const { 701 return TryDispatchBlocks.begin(); 702 } 703 try_block_iterator try_blocks_end() const { 704 return TryDispatchBlocks.end(); 705 } 706 707 void addTryDispatchBlock(const CFGBlock *block) { 708 TryDispatchBlocks.push_back(block); 709 } 710 711 //===--------------------------------------------------------------------===// 712 // Member templates useful for various batch operations over CFGs. 713 //===--------------------------------------------------------------------===// 714 715 template <typename CALLBACK> 716 void VisitBlockStmts(CALLBACK& O) const { 717 for (const_iterator I=begin(), E=end(); I != E; ++I) 718 for (CFGBlock::const_iterator BI=(*I)->begin(), BE=(*I)->end(); 719 BI != BE; ++BI) { 720 if (const CFGStmt *stmt = BI->getAs<CFGStmt>()) 721 O(const_cast<Stmt*>(stmt->getStmt())); 722 } 723 } 724 725 //===--------------------------------------------------------------------===// 726 // CFG Introspection. 727 //===--------------------------------------------------------------------===// 728 729 struct BlkExprNumTy { 730 const signed Idx; 731 explicit BlkExprNumTy(signed idx) : Idx(idx) {} 732 explicit BlkExprNumTy() : Idx(-1) {} 733 operator bool() const { return Idx >= 0; } 734 operator unsigned() const { assert(Idx >=0); return (unsigned) Idx; } 735 }; 736 737 bool isBlkExpr(const Stmt *S) { return getBlkExprNum(S); } 738 bool isBlkExpr(const Stmt *S) const { 739 return const_cast<CFG*>(this)->isBlkExpr(S); 740 } 741 BlkExprNumTy getBlkExprNum(const Stmt *S); 742 unsigned getNumBlkExprs(); 743 744 /// getNumBlockIDs - Returns the total number of BlockIDs allocated (which 745 /// start at 0). 746 unsigned getNumBlockIDs() const { return NumBlockIDs; } 747 748 /// size - Return the total number of CFGBlocks within the CFG 749 /// This is simply a renaming of the getNumBlockIDs(). This is necessary 750 /// because the dominator implementation needs such an interface. 751 unsigned size() const { return NumBlockIDs; } 752 753 //===--------------------------------------------------------------------===// 754 // CFG Debugging: Pretty-Printing and Visualization. 755 //===--------------------------------------------------------------------===// 756 757 void viewCFG(const LangOptions &LO) const; 758 void print(raw_ostream &OS, const LangOptions &LO) const; 759 void dump(const LangOptions &LO) const; 760 761 //===--------------------------------------------------------------------===// 762 // Internal: constructors and data. 763 //===--------------------------------------------------------------------===// 764 765 CFG() : Entry(NULL), Exit(NULL), IndirectGotoBlock(NULL), NumBlockIDs(0), 766 BlkExprMap(NULL), Blocks(BlkBVC, 10) {} 767 768 ~CFG(); 769 770 llvm::BumpPtrAllocator& getAllocator() { 771 return BlkBVC.getAllocator(); 772 } 773 774 BumpVectorContext &getBumpVectorContext() { 775 return BlkBVC; 776 } 777 778private: 779 CFGBlock *Entry; 780 CFGBlock *Exit; 781 CFGBlock* IndirectGotoBlock; // Special block to contain collective dispatch 782 // for indirect gotos 783 unsigned NumBlockIDs; 784 785 // BlkExprMap - An opaque pointer to prevent inclusion of DenseMap.h. 786 // It represents a map from Expr* to integers to record the set of 787 // block-level expressions and their "statement number" in the CFG. 788 void * BlkExprMap; 789 790 BumpVectorContext BlkBVC; 791 792 CFGBlockListTy Blocks; 793 794 /// C++ 'try' statements are modeled with an indirect dispatch block. 795 /// This is the collection of such blocks present in the CFG. 796 std::vector<const CFGBlock *> TryDispatchBlocks; 797 798}; 799} // end namespace clang 800 801//===----------------------------------------------------------------------===// 802// GraphTraits specializations for CFG basic block graphs (source-level CFGs) 803//===----------------------------------------------------------------------===// 804 805namespace llvm { 806 807/// Implement simplify_type for CFGTerminator, so that we can dyn_cast from 808/// CFGTerminator to a specific Stmt class. 809template <> struct simplify_type<const ::clang::CFGTerminator> { 810 typedef const ::clang::Stmt *SimpleType; 811 static SimpleType getSimplifiedValue(const ::clang::CFGTerminator &Val) { 812 return Val.getStmt(); 813 } 814}; 815 816template <> struct simplify_type< ::clang::CFGTerminator> { 817 typedef ::clang::Stmt *SimpleType; 818 static SimpleType getSimplifiedValue(const ::clang::CFGTerminator &Val) { 819 return const_cast<SimpleType>(Val.getStmt()); 820 } 821}; 822 823// Traits for: CFGBlock 824 825template <> struct GraphTraits< ::clang::CFGBlock *> { 826 typedef ::clang::CFGBlock NodeType; 827 typedef ::clang::CFGBlock::succ_iterator ChildIteratorType; 828 829 static NodeType* getEntryNode(::clang::CFGBlock *BB) 830 { return BB; } 831 832 static inline ChildIteratorType child_begin(NodeType* N) 833 { return N->succ_begin(); } 834 835 static inline ChildIteratorType child_end(NodeType* N) 836 { return N->succ_end(); } 837}; 838 839template <> struct GraphTraits< const ::clang::CFGBlock *> { 840 typedef const ::clang::CFGBlock NodeType; 841 typedef ::clang::CFGBlock::const_succ_iterator ChildIteratorType; 842 843 static NodeType* getEntryNode(const clang::CFGBlock *BB) 844 { return BB; } 845 846 static inline ChildIteratorType child_begin(NodeType* N) 847 { return N->succ_begin(); } 848 849 static inline ChildIteratorType child_end(NodeType* N) 850 { return N->succ_end(); } 851}; 852 853template <> struct GraphTraits<Inverse< ::clang::CFGBlock*> > { 854 typedef ::clang::CFGBlock NodeType; 855 typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType; 856 857 static NodeType *getEntryNode(Inverse< ::clang::CFGBlock*> G) 858 { return G.Graph; } 859 860 static inline ChildIteratorType child_begin(NodeType* N) 861 { return N->pred_begin(); } 862 863 static inline ChildIteratorType child_end(NodeType* N) 864 { return N->pred_end(); } 865}; 866 867template <> struct GraphTraits<Inverse<const ::clang::CFGBlock*> > { 868 typedef const ::clang::CFGBlock NodeType; 869 typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType; 870 871 static NodeType *getEntryNode(Inverse<const ::clang::CFGBlock*> G) 872 { return G.Graph; } 873 874 static inline ChildIteratorType child_begin(NodeType* N) 875 { return N->pred_begin(); } 876 877 static inline ChildIteratorType child_end(NodeType* N) 878 { return N->pred_end(); } 879}; 880 881// Traits for: CFG 882 883template <> struct GraphTraits< ::clang::CFG* > 884 : public GraphTraits< ::clang::CFGBlock *> { 885 886 typedef ::clang::CFG::graph_iterator nodes_iterator; 887 888 static NodeType *getEntryNode(::clang::CFG* F) { return &F->getEntry(); } 889 static nodes_iterator nodes_begin(::clang::CFG* F) { return F->nodes_begin();} 890 static nodes_iterator nodes_end(::clang::CFG* F) { return F->nodes_end(); } 891 static unsigned size(::clang::CFG* F) { return F->size(); } 892}; 893 894template <> struct GraphTraits<const ::clang::CFG* > 895 : public GraphTraits<const ::clang::CFGBlock *> { 896 897 typedef ::clang::CFG::const_graph_iterator nodes_iterator; 898 899 static NodeType *getEntryNode( const ::clang::CFG* F) { 900 return &F->getEntry(); 901 } 902 static nodes_iterator nodes_begin( const ::clang::CFG* F) { 903 return F->nodes_begin(); 904 } 905 static nodes_iterator nodes_end( const ::clang::CFG* F) { 906 return F->nodes_end(); 907 } 908 static unsigned size(const ::clang::CFG* F) { 909 return F->size(); 910 } 911}; 912 913template <> struct GraphTraits<Inverse< ::clang::CFG*> > 914 : public GraphTraits<Inverse< ::clang::CFGBlock*> > { 915 916 typedef ::clang::CFG::graph_iterator nodes_iterator; 917 918 static NodeType *getEntryNode( ::clang::CFG* F) { return &F->getExit(); } 919 static nodes_iterator nodes_begin( ::clang::CFG* F) {return F->nodes_begin();} 920 static nodes_iterator nodes_end( ::clang::CFG* F) { return F->nodes_end(); } 921}; 922 923template <> struct GraphTraits<Inverse<const ::clang::CFG*> > 924 : public GraphTraits<Inverse<const ::clang::CFGBlock*> > { 925 926 typedef ::clang::CFG::const_graph_iterator nodes_iterator; 927 928 static NodeType *getEntryNode(const ::clang::CFG* F) { return &F->getExit(); } 929 static nodes_iterator nodes_begin(const ::clang::CFG* F) { 930 return F->nodes_begin(); 931 } 932 static nodes_iterator nodes_end(const ::clang::CFG* F) { 933 return F->nodes_end(); 934 } 935}; 936} // end llvm namespace 937#endif 938