CFG.h revision 36d558d85653315edb389677e995ec9ccdbfbf3d 
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 "clang/AST/Stmt.h"
19#include "clang/Analysis/Support/BumpVector.h"
20#include "clang/Basic/SourceLocation.h"
21#include "llvm/ADT/DenseMap.h"
22#include "llvm/ADT/GraphTraits.h"
23#include "llvm/ADT/Optional.h"
24#include "llvm/ADT/OwningPtr.h"
25#include "llvm/ADT/PointerIntPair.h"
26#include "llvm/Support/Allocator.h"
27#include "llvm/Support/Casting.h"
28#include <bitset>
29#include <cassert>
30#include <iterator>
31
32namespace clang {
33  class CXXDestructorDecl;
34  class Decl;
35  class Stmt;
36  class Expr;
37  class FieldDecl;
38  class VarDecl;
39  class CXXCtorInitializer;
40  class CXXBaseSpecifier;
41  class CXXBindTemporaryExpr;
42  class CFG;
43  class PrinterHelper;
44  class LangOptions;
45  class ASTContext;
46  class CXXRecordDecl;
47  class CXXDeleteExpr;
48
49/// CFGElement - Represents a top-level expression in a basic block.
50class CFGElement {
51public:
52  enum Kind {
53    // main kind
54    Statement,
55    Initializer,
56    // dtor kind
57    AutomaticObjectDtor,
58    DeleteDtor,
59    BaseDtor,
60    MemberDtor,
61    TemporaryDtor,
62    DTOR_BEGIN = AutomaticObjectDtor,
63    DTOR_END = TemporaryDtor
64  };
65
66protected:
67  // The int bits are used to mark the kind.
68  llvm::PointerIntPair<void *, 2> Data1;
69  llvm::PointerIntPair<void *, 2> Data2;
70
71  CFGElement(Kind kind, const void *Ptr1, const void *Ptr2 = 0)
72    : Data1(const_cast<void*>(Ptr1), ((unsigned) kind) & 0x3),
73      Data2(const_cast<void*>(Ptr2), (((unsigned) kind) >> 2) & 0x3) {}
74
75  CFGElement() {}
76public:
77
78  /// \brief Convert to the specified CFGElement type, asserting that this
79  /// CFGElement is of the desired type.
80  template<typename T>
81  T castAs() const {
82    assert(T::isKind(*this));
83    T t;
84    CFGElement& e = t;
85    e = *this;
86    return t;
87  }
88
89  /// \brief Convert to the specified CFGElement type, returning None if this
90  /// CFGElement is not of the desired type.
91  template<typename T>
92  Optional<T> getAs() const {
93    if (!T::isKind(*this))
94      return None;
95    T t;
96    CFGElement& e = t;
97    e = *this;
98    return t;
99  }
100
101  Kind getKind() const {
102    unsigned x = Data2.getInt();
103    x <<= 2;
104    x |= Data1.getInt();
105    return (Kind) x;
106  }
107};
108
109class CFGStmt : public CFGElement {
110public:
111  CFGStmt(Stmt *S) : CFGElement(Statement, S) {}
112
113  const Stmt *getStmt() const {
114    return static_cast<const Stmt *>(Data1.getPointer());
115  }
116
117private:
118  friend class CFGElement;
119  CFGStmt() {}
120  static bool isKind(const CFGElement &E) {
121    return E.getKind() == Statement;
122  }
123};
124
125/// CFGInitializer - Represents C++ base or member initializer from
126/// constructor's initialization list.
127class CFGInitializer : public CFGElement {
128public:
129  CFGInitializer(CXXCtorInitializer *initializer)
130      : CFGElement(Initializer, initializer) {}
131
132  CXXCtorInitializer* getInitializer() const {
133    return static_cast<CXXCtorInitializer*>(Data1.getPointer());
134  }
135
136private:
137  friend class CFGElement;
138  CFGInitializer() {}
139  static bool isKind(const CFGElement &E) {
140    return E.getKind() == Initializer;
141  }
142};
143
144/// CFGImplicitDtor - Represents C++ object destructor implicitly generated
145/// by compiler on various occasions.
146class CFGImplicitDtor : public CFGElement {
147protected:
148  CFGImplicitDtor() {}
149  CFGImplicitDtor(Kind kind, const void *data1, const void *data2 = 0)
150    : CFGElement(kind, data1, data2) {
151    assert(kind >= DTOR_BEGIN && kind <= DTOR_END);
152  }
153
154public:
155  const CXXDestructorDecl *getDestructorDecl(ASTContext &astContext) const;
156  bool isNoReturn(ASTContext &astContext) const;
157
158private:
159  friend class CFGElement;
160  static bool isKind(const CFGElement &E) {
161    Kind kind = E.getKind();
162    return kind >= DTOR_BEGIN && kind <= DTOR_END;
163  }
164};
165
166/// CFGAutomaticObjDtor - Represents C++ object destructor implicitly generated
167/// for automatic object or temporary bound to const reference at the point
168/// of leaving its local scope.
169class CFGAutomaticObjDtor: public CFGImplicitDtor {
170public:
171  CFGAutomaticObjDtor(const VarDecl *var, const Stmt *stmt)
172      : CFGImplicitDtor(AutomaticObjectDtor, var, stmt) {}
173
174  const VarDecl *getVarDecl() const {
175    return static_cast<VarDecl*>(Data1.getPointer());
176  }
177
178  // Get statement end of which triggered the destructor call.
179  const Stmt *getTriggerStmt() const {
180    return static_cast<Stmt*>(Data2.getPointer());
181  }
182
183private:
184  friend class CFGElement;
185  CFGAutomaticObjDtor() {}
186  static bool isKind(const CFGElement &elem) {
187    return elem.getKind() == AutomaticObjectDtor;
188  }
189};
190
191/// CFGDeleteDtor - Represents C++ object destructor generated
192/// from a call to delete.
193class CFGDeleteDtor : public CFGImplicitDtor {
194public:
195  CFGDeleteDtor(const CXXRecordDecl *RD, const CXXDeleteExpr *DE)
196      : CFGImplicitDtor(DeleteDtor, RD, DE) {}
197
198  const CXXRecordDecl *getCXXRecordDecl() const {
199    return static_cast<CXXRecordDecl*>(Data1.getPointer());
200  }
201
202  // Get Delete expression which triggered the destructor call.
203  const CXXDeleteExpr *getDeleteExpr() {
204    return static_cast<CXXDeleteExpr *>(Data2.getPointer());
205  }
206
207
208private:
209  friend class CFGElement;
210  CFGDeleteDtor() {}
211  static bool isKind(const CFGElement &elem) {
212    return elem.getKind() == DeleteDtor;
213  }
214};
215
216/// CFGBaseDtor - Represents C++ object destructor implicitly generated for
217/// base object in destructor.
218class CFGBaseDtor : public CFGImplicitDtor {
219public:
220  CFGBaseDtor(const CXXBaseSpecifier *base)
221      : CFGImplicitDtor(BaseDtor, base) {}
222
223  const CXXBaseSpecifier *getBaseSpecifier() const {
224    return static_cast<const CXXBaseSpecifier*>(Data1.getPointer());
225  }
226
227private:
228  friend class CFGElement;
229  CFGBaseDtor() {}
230  static bool isKind(const CFGElement &E) {
231    return E.getKind() == BaseDtor;
232  }
233};
234
235/// CFGMemberDtor - Represents C++ object destructor implicitly generated for
236/// member object in destructor.
237class CFGMemberDtor : public CFGImplicitDtor {
238public:
239  CFGMemberDtor(const FieldDecl *field)
240      : CFGImplicitDtor(MemberDtor, field, 0) {}
241
242  const FieldDecl *getFieldDecl() const {
243    return static_cast<const FieldDecl*>(Data1.getPointer());
244  }
245
246private:
247  friend class CFGElement;
248  CFGMemberDtor() {}
249  static bool isKind(const CFGElement &E) {
250    return E.getKind() == MemberDtor;
251  }
252};
253
254/// CFGTemporaryDtor - Represents C++ object destructor implicitly generated
255/// at the end of full expression for temporary object.
256class CFGTemporaryDtor : public CFGImplicitDtor {
257public:
258  CFGTemporaryDtor(CXXBindTemporaryExpr *expr)
259      : CFGImplicitDtor(TemporaryDtor, expr, 0) {}
260
261  const CXXBindTemporaryExpr *getBindTemporaryExpr() const {
262    return static_cast<const CXXBindTemporaryExpr *>(Data1.getPointer());
263  }
264
265private:
266  friend class CFGElement;
267  CFGTemporaryDtor() {}
268  static bool isKind(const CFGElement &E) {
269    return E.getKind() == TemporaryDtor;
270  }
271};
272
273/// CFGTerminator - Represents CFGBlock terminator statement.
274///
275/// TemporaryDtorsBranch bit is set to true if the terminator marks a branch
276/// in control flow of destructors of temporaries. In this case terminator
277/// statement is the same statement that branches control flow in evaluation
278/// of matching full expression.
279class CFGTerminator {
280  llvm::PointerIntPair<Stmt *, 1> Data;
281public:
282  CFGTerminator() {}
283  CFGTerminator(Stmt *S, bool TemporaryDtorsBranch = false)
284      : Data(S, TemporaryDtorsBranch) {}
285
286  Stmt *getStmt() { return Data.getPointer(); }
287  const Stmt *getStmt() const { return Data.getPointer(); }
288
289  bool isTemporaryDtorsBranch() const { return Data.getInt(); }
290
291  operator Stmt *() { return getStmt(); }
292  operator const Stmt *() const { return getStmt(); }
293
294  Stmt *operator->() { return getStmt(); }
295  const Stmt *operator->() const { return getStmt(); }
296
297  Stmt &operator*() { return *getStmt(); }
298  const Stmt &operator*() const { return *getStmt(); }
299
300  LLVM_EXPLICIT operator bool() const { return getStmt(); }
301};
302
303/// CFGBlock - Represents a single basic block in a source-level CFG.
304///  It consists of:
305///
306///  (1) A set of statements/expressions (which may contain subexpressions).
307///  (2) A "terminator" statement (not in the set of statements).
308///  (3) A list of successors and predecessors.
309///
310/// Terminator: The terminator represents the type of control-flow that occurs
311/// at the end of the basic block.  The terminator is a Stmt* referring to an
312/// AST node that has control-flow: if-statements, breaks, loops, etc.
313/// If the control-flow is conditional, the condition expression will appear
314/// within the set of statements in the block (usually the last statement).
315///
316/// Predecessors: the order in the set of predecessors is arbitrary.
317///
318/// Successors: the order in the set of successors is NOT arbitrary.  We
319///  currently have the following orderings based on the terminator:
320///
321///     Terminator       Successor Ordering
322///  -----------------------------------------------------
323///       if            Then Block;  Else Block
324///     ? operator      LHS expression;  RHS expression
325///     &&, ||          expression that uses result of && or ||, RHS
326///
327/// But note that any of that may be NULL in case of optimized-out edges.
328///
329class CFGBlock {
330  class ElementList {
331    typedef BumpVector<CFGElement> ImplTy;
332    ImplTy Impl;
333  public:
334    ElementList(BumpVectorContext &C) : Impl(C, 4) {}
335
336    typedef std::reverse_iterator<ImplTy::iterator>       iterator;
337    typedef std::reverse_iterator<ImplTy::const_iterator> const_iterator;
338    typedef ImplTy::iterator                              reverse_iterator;
339    typedef ImplTy::const_iterator                       const_reverse_iterator;
340    typedef ImplTy::const_reference                       const_reference;
341
342    void push_back(CFGElement e, BumpVectorContext &C) { Impl.push_back(e, C); }
343    reverse_iterator insert(reverse_iterator I, size_t Cnt, CFGElement E,
344        BumpVectorContext &C) {
345      return Impl.insert(I, Cnt, E, C);
346    }
347
348    const_reference front() const { return Impl.back(); }
349    const_reference back() const { return Impl.front(); }
350
351    iterator begin() { return Impl.rbegin(); }
352    iterator end() { return Impl.rend(); }
353    const_iterator begin() const { return Impl.rbegin(); }
354    const_iterator end() const { return Impl.rend(); }
355    reverse_iterator rbegin() { return Impl.begin(); }
356    reverse_iterator rend() { return Impl.end(); }
357    const_reverse_iterator rbegin() const { return Impl.begin(); }
358    const_reverse_iterator rend() const { return Impl.end(); }
359
360   CFGElement operator[](size_t i) const  {
361     assert(i < Impl.size());
362     return Impl[Impl.size() - 1 - i];
363   }
364
365    size_t size() const { return Impl.size(); }
366    bool empty() const { return Impl.empty(); }
367  };
368
369  /// Stmts - The set of statements in the basic block.
370  ElementList Elements;
371
372  /// Label - An (optional) label that prefixes the executable
373  ///  statements in the block.  When this variable is non-NULL, it is
374  ///  either an instance of LabelStmt, SwitchCase or CXXCatchStmt.
375  Stmt *Label;
376
377  /// Terminator - The terminator for a basic block that
378  ///  indicates the type of control-flow that occurs between a block
379  ///  and its successors.
380  CFGTerminator Terminator;
381
382  /// LoopTarget - Some blocks are used to represent the "loop edge" to
383  ///  the start of a loop from within the loop body.  This Stmt* will be
384  ///  refer to the loop statement for such blocks (and be null otherwise).
385  const Stmt *LoopTarget;
386
387  /// BlockID - A numerical ID assigned to a CFGBlock during construction
388  ///   of the CFG.
389  unsigned BlockID;
390
391  /// Predecessors/Successors - Keep track of the predecessor / successor
392  /// CFG blocks.
393  typedef BumpVector<CFGBlock*> AdjacentBlocks;
394  AdjacentBlocks Preds;
395  AdjacentBlocks Succs;
396
397  /// NoReturn - This bit is set when the basic block contains a function call
398  /// or implicit destructor that is attributed as 'noreturn'. In that case,
399  /// control cannot technically ever proceed past this block. All such blocks
400  /// will have a single immediate successor: the exit block. This allows them
401  /// to be easily reached from the exit block and using this bit quickly
402  /// recognized without scanning the contents of the block.
403  ///
404  /// Optimization Note: This bit could be profitably folded with Terminator's
405  /// storage if the memory usage of CFGBlock becomes an issue.
406  unsigned HasNoReturnElement : 1;
407
408  /// Parent - The parent CFG that owns this CFGBlock.
409  CFG *Parent;
410
411public:
412  explicit CFGBlock(unsigned blockid, BumpVectorContext &C, CFG *parent)
413    : Elements(C), Label(NULL), Terminator(NULL), LoopTarget(NULL),
414      BlockID(blockid), Preds(C, 1), Succs(C, 1), HasNoReturnElement(false),
415      Parent(parent) {}
416  ~CFGBlock() {}
417
418  // Statement iterators
419  typedef ElementList::iterator                      iterator;
420  typedef ElementList::const_iterator                const_iterator;
421  typedef ElementList::reverse_iterator              reverse_iterator;
422  typedef ElementList::const_reverse_iterator        const_reverse_iterator;
423
424  CFGElement                 front()       const { return Elements.front();   }
425  CFGElement                 back()        const { return Elements.back();    }
426
427  iterator                   begin()             { return Elements.begin();   }
428  iterator                   end()               { return Elements.end();     }
429  const_iterator             begin()       const { return Elements.begin();   }
430  const_iterator             end()         const { return Elements.end();     }
431
432  reverse_iterator           rbegin()            { return Elements.rbegin();  }
433  reverse_iterator           rend()              { return Elements.rend();    }
434  const_reverse_iterator     rbegin()      const { return Elements.rbegin();  }
435  const_reverse_iterator     rend()        const { return Elements.rend();    }
436
437  unsigned                   size()        const { return Elements.size();    }
438  bool                       empty()       const { return Elements.empty();   }
439
440  CFGElement operator[](size_t i) const  { return Elements[i]; }
441
442  // CFG iterators
443  typedef AdjacentBlocks::iterator                              pred_iterator;
444  typedef AdjacentBlocks::const_iterator                  const_pred_iterator;
445  typedef AdjacentBlocks::reverse_iterator              pred_reverse_iterator;
446  typedef AdjacentBlocks::const_reverse_iterator  const_pred_reverse_iterator;
447
448  typedef AdjacentBlocks::iterator                              succ_iterator;
449  typedef AdjacentBlocks::const_iterator                  const_succ_iterator;
450  typedef AdjacentBlocks::reverse_iterator              succ_reverse_iterator;
451  typedef AdjacentBlocks::const_reverse_iterator  const_succ_reverse_iterator;
452
453  pred_iterator                pred_begin()        { return Preds.begin();   }
454  pred_iterator                pred_end()          { return Preds.end();     }
455  const_pred_iterator          pred_begin()  const { return Preds.begin();   }
456  const_pred_iterator          pred_end()    const { return Preds.end();     }
457
458  pred_reverse_iterator        pred_rbegin()       { return Preds.rbegin();  }
459  pred_reverse_iterator        pred_rend()         { return Preds.rend();    }
460  const_pred_reverse_iterator  pred_rbegin() const { return Preds.rbegin();  }
461  const_pred_reverse_iterator  pred_rend()   const { return Preds.rend();    }
462
463  succ_iterator                succ_begin()        { return Succs.begin();   }
464  succ_iterator                succ_end()          { return Succs.end();     }
465  const_succ_iterator          succ_begin()  const { return Succs.begin();   }
466  const_succ_iterator          succ_end()    const { return Succs.end();     }
467
468  succ_reverse_iterator        succ_rbegin()       { return Succs.rbegin();  }
469  succ_reverse_iterator        succ_rend()         { return Succs.rend();    }
470  const_succ_reverse_iterator  succ_rbegin() const { return Succs.rbegin();  }
471  const_succ_reverse_iterator  succ_rend()   const { return Succs.rend();    }
472
473  unsigned                     succ_size()   const { return Succs.size();    }
474  bool                         succ_empty()  const { return Succs.empty();   }
475
476  unsigned                     pred_size()   const { return Preds.size();    }
477  bool                         pred_empty()  const { return Preds.empty();   }
478
479
480  class FilterOptions {
481  public:
482    FilterOptions() {
483      IgnoreDefaultsWithCoveredEnums = 0;
484    }
485
486    unsigned IgnoreDefaultsWithCoveredEnums : 1;
487  };
488
489  static bool FilterEdge(const FilterOptions &F, const CFGBlock *Src,
490       const CFGBlock *Dst);
491
492  template <typename IMPL, bool IsPred>
493  class FilteredCFGBlockIterator {
494  private:
495    IMPL I, E;
496    const FilterOptions F;
497    const CFGBlock *From;
498   public:
499    explicit FilteredCFGBlockIterator(const IMPL &i, const IMPL &e,
500              const CFGBlock *from,
501              const FilterOptions &f)
502      : I(i), E(e), F(f), From(from) {}
503
504    bool hasMore() const { return I != E; }
505
506    FilteredCFGBlockIterator &operator++() {
507      do { ++I; } while (hasMore() && Filter(*I));
508      return *this;
509    }
510
511    const CFGBlock *operator*() const { return *I; }
512  private:
513    bool Filter(const CFGBlock *To) {
514      return IsPred ? FilterEdge(F, To, From) : FilterEdge(F, From, To);
515    }
516  };
517
518  typedef FilteredCFGBlockIterator<const_pred_iterator, true>
519          filtered_pred_iterator;
520
521  typedef FilteredCFGBlockIterator<const_succ_iterator, false>
522          filtered_succ_iterator;
523
524  filtered_pred_iterator filtered_pred_start_end(const FilterOptions &f) const {
525    return filtered_pred_iterator(pred_begin(), pred_end(), this, f);
526  }
527
528  filtered_succ_iterator filtered_succ_start_end(const FilterOptions &f) const {
529    return filtered_succ_iterator(succ_begin(), succ_end(), this, f);
530  }
531
532  // Manipulation of block contents
533
534  void setTerminator(Stmt *Statement) { Terminator = Statement; }
535  void setLabel(Stmt *Statement) { Label = Statement; }
536  void setLoopTarget(const Stmt *loopTarget) { LoopTarget = loopTarget; }
537  void setHasNoReturnElement() { HasNoReturnElement = true; }
538
539  CFGTerminator getTerminator() { return Terminator; }
540  const CFGTerminator getTerminator() const { return Terminator; }
541
542  Stmt *getTerminatorCondition();
543
544  const Stmt *getTerminatorCondition() const {
545    return const_cast<CFGBlock*>(this)->getTerminatorCondition();
546  }
547
548  const Stmt *getLoopTarget() const { return LoopTarget; }
549
550  Stmt *getLabel() { return Label; }
551  const Stmt *getLabel() const { return Label; }
552
553  bool hasNoReturnElement() const { return HasNoReturnElement; }
554
555  unsigned getBlockID() const { return BlockID; }
556
557  CFG *getParent() const { return Parent; }
558
559  void dump(const CFG *cfg, const LangOptions &LO, bool ShowColors = false) const;
560  void print(raw_ostream &OS, const CFG* cfg, const LangOptions &LO,
561             bool ShowColors) const;
562  void printTerminator(raw_ostream &OS, const LangOptions &LO) const;
563
564  void addSuccessor(CFGBlock *Block, BumpVectorContext &C) {
565    if (Block)
566      Block->Preds.push_back(this, C);
567    Succs.push_back(Block, C);
568  }
569
570  void appendStmt(Stmt *statement, BumpVectorContext &C) {
571    Elements.push_back(CFGStmt(statement), C);
572  }
573
574  void appendInitializer(CXXCtorInitializer *initializer,
575                        BumpVectorContext &C) {
576    Elements.push_back(CFGInitializer(initializer), C);
577  }
578
579  void appendBaseDtor(const CXXBaseSpecifier *BS, BumpVectorContext &C) {
580    Elements.push_back(CFGBaseDtor(BS), C);
581  }
582
583  void appendMemberDtor(FieldDecl *FD, BumpVectorContext &C) {
584    Elements.push_back(CFGMemberDtor(FD), C);
585  }
586
587  void appendTemporaryDtor(CXXBindTemporaryExpr *E, BumpVectorContext &C) {
588    Elements.push_back(CFGTemporaryDtor(E), C);
589  }
590
591  void appendAutomaticObjDtor(VarDecl *VD, Stmt *S, BumpVectorContext &C) {
592    Elements.push_back(CFGAutomaticObjDtor(VD, S), C);
593  }
594
595  void appendDeleteDtor(CXXRecordDecl *RD, CXXDeleteExpr *DE, BumpVectorContext &C) {
596    Elements.push_back(CFGDeleteDtor(RD, DE), C);
597  }
598
599  // Destructors must be inserted in reversed order. So insertion is in two
600  // steps. First we prepare space for some number of elements, then we insert
601  // the elements beginning at the last position in prepared space.
602  iterator beginAutomaticObjDtorsInsert(iterator I, size_t Cnt,
603      BumpVectorContext &C) {
604    return iterator(Elements.insert(I.base(), Cnt, CFGAutomaticObjDtor(0, 0), C));
605  }
606  iterator insertAutomaticObjDtor(iterator I, VarDecl *VD, Stmt *S) {
607    *I = CFGAutomaticObjDtor(VD, S);
608    return ++I;
609  }
610};
611
612/// CFG - Represents a source-level, intra-procedural CFG that represents the
613///  control-flow of a Stmt.  The Stmt can represent an entire function body,
614///  or a single expression.  A CFG will always contain one empty block that
615///  represents the Exit point of the CFG.  A CFG will also contain a designated
616///  Entry block.  The CFG solely represents control-flow; it consists of
617///  CFGBlocks which are simply containers of Stmt*'s in the AST the CFG
618///  was constructed from.
619class CFG {
620public:
621  //===--------------------------------------------------------------------===//
622  // CFG Construction & Manipulation.
623  //===--------------------------------------------------------------------===//
624
625  class BuildOptions {
626    std::bitset<Stmt::lastStmtConstant> alwaysAddMask;
627  public:
628    typedef llvm::DenseMap<const Stmt *, const CFGBlock*> ForcedBlkExprs;
629    ForcedBlkExprs **forcedBlkExprs;
630
631    bool PruneTriviallyFalseEdges;
632    bool AddEHEdges;
633    bool AddInitializers;
634    bool AddImplicitDtors;
635    bool AddTemporaryDtors;
636    bool AddStaticInitBranches;
637
638    bool alwaysAdd(const Stmt *stmt) const {
639      return alwaysAddMask[stmt->getStmtClass()];
640    }
641
642    BuildOptions &setAlwaysAdd(Stmt::StmtClass stmtClass, bool val = true) {
643      alwaysAddMask[stmtClass] = val;
644      return *this;
645    }
646
647    BuildOptions &setAllAlwaysAdd() {
648      alwaysAddMask.set();
649      return *this;
650    }
651
652    BuildOptions()
653    : forcedBlkExprs(0), PruneTriviallyFalseEdges(true)
654      ,AddEHEdges(false)
655      ,AddInitializers(false)
656      ,AddImplicitDtors(false)
657      ,AddTemporaryDtors(false)
658      ,AddStaticInitBranches(false) {}
659  };
660
661  /// \brief Provides a custom implementation of the iterator class to have the
662  /// same interface as Function::iterator - iterator returns CFGBlock
663  /// (not a pointer to CFGBlock).
664  class graph_iterator {
665  public:
666    typedef const CFGBlock                  value_type;
667    typedef value_type&                     reference;
668    typedef value_type*                     pointer;
669    typedef BumpVector<CFGBlock*>::iterator ImplTy;
670
671    graph_iterator(const ImplTy &i) : I(i) {}
672
673    bool operator==(const graph_iterator &X) const { return I == X.I; }
674    bool operator!=(const graph_iterator &X) const { return I != X.I; }
675
676    reference operator*()    const { return **I; }
677    pointer operator->()     const { return  *I; }
678    operator CFGBlock* ()          { return  *I; }
679
680    graph_iterator &operator++() { ++I; return *this; }
681    graph_iterator &operator--() { --I; return *this; }
682
683  private:
684    ImplTy I;
685  };
686
687  class const_graph_iterator {
688  public:
689    typedef const CFGBlock                  value_type;
690    typedef value_type&                     reference;
691    typedef value_type*                     pointer;
692    typedef BumpVector<CFGBlock*>::const_iterator ImplTy;
693
694    const_graph_iterator(const ImplTy &i) : I(i) {}
695
696    bool operator==(const const_graph_iterator &X) const { return I == X.I; }
697    bool operator!=(const const_graph_iterator &X) const { return I != X.I; }
698
699    reference operator*() const { return **I; }
700    pointer operator->()  const { return  *I; }
701    operator CFGBlock* () const { return  *I; }
702
703    const_graph_iterator &operator++() { ++I; return *this; }
704    const_graph_iterator &operator--() { --I; return *this; }
705
706  private:
707    ImplTy I;
708  };
709
710  /// buildCFG - Builds a CFG from an AST.  The responsibility to free the
711  ///   constructed CFG belongs to the caller.
712  static CFG* buildCFG(const Decl *D, Stmt *AST, ASTContext *C,
713                       const BuildOptions &BO);
714
715  /// createBlock - Create a new block in the CFG.  The CFG owns the block;
716  ///  the caller should not directly free it.
717  CFGBlock *createBlock();
718
719  /// setEntry - Set the entry block of the CFG.  This is typically used
720  ///  only during CFG construction.  Most CFG clients expect that the
721  ///  entry block has no predecessors and contains no statements.
722  void setEntry(CFGBlock *B) { Entry = B; }
723
724  /// setIndirectGotoBlock - Set the block used for indirect goto jumps.
725  ///  This is typically used only during CFG construction.
726  void setIndirectGotoBlock(CFGBlock *B) { IndirectGotoBlock = B; }
727
728  //===--------------------------------------------------------------------===//
729  // Block Iterators
730  //===--------------------------------------------------------------------===//
731
732  typedef BumpVector<CFGBlock*>                    CFGBlockListTy;
733  typedef CFGBlockListTy::iterator                 iterator;
734  typedef CFGBlockListTy::const_iterator           const_iterator;
735  typedef std::reverse_iterator<iterator>          reverse_iterator;
736  typedef std::reverse_iterator<const_iterator>    const_reverse_iterator;
737
738  CFGBlock &                front()                { return *Blocks.front(); }
739  CFGBlock &                back()                 { return *Blocks.back(); }
740
741  iterator                  begin()                { return Blocks.begin(); }
742  iterator                  end()                  { return Blocks.end(); }
743  const_iterator            begin()       const    { return Blocks.begin(); }
744  const_iterator            end()         const    { return Blocks.end(); }
745
746  graph_iterator nodes_begin() { return graph_iterator(Blocks.begin()); }
747  graph_iterator nodes_end() { return graph_iterator(Blocks.end()); }
748  const_graph_iterator nodes_begin() const {
749    return const_graph_iterator(Blocks.begin());
750  }
751  const_graph_iterator nodes_end() const {
752    return const_graph_iterator(Blocks.end());
753  }
754
755  reverse_iterator          rbegin()               { return Blocks.rbegin(); }
756  reverse_iterator          rend()                 { return Blocks.rend(); }
757  const_reverse_iterator    rbegin()      const    { return Blocks.rbegin(); }
758  const_reverse_iterator    rend()        const    { return Blocks.rend(); }
759
760  CFGBlock &                getEntry()             { return *Entry; }
761  const CFGBlock &          getEntry()    const    { return *Entry; }
762  CFGBlock &                getExit()              { return *Exit; }
763  const CFGBlock &          getExit()     const    { return *Exit; }
764
765  CFGBlock *       getIndirectGotoBlock() { return IndirectGotoBlock; }
766  const CFGBlock * getIndirectGotoBlock() const { return IndirectGotoBlock; }
767
768  typedef std::vector<const CFGBlock*>::const_iterator try_block_iterator;
769  try_block_iterator try_blocks_begin() const {
770    return TryDispatchBlocks.begin();
771  }
772  try_block_iterator try_blocks_end() const {
773    return TryDispatchBlocks.end();
774  }
775
776  void addTryDispatchBlock(const CFGBlock *block) {
777    TryDispatchBlocks.push_back(block);
778  }
779
780  /// Records a synthetic DeclStmt and the DeclStmt it was constructed from.
781  ///
782  /// The CFG uses synthetic DeclStmts when a single AST DeclStmt contains
783  /// multiple decls.
784  void addSyntheticDeclStmt(const DeclStmt *Synthetic,
785                            const DeclStmt *Source) {
786    assert(Synthetic->isSingleDecl() && "Can handle single declarations only");
787    assert(Synthetic != Source && "Don't include original DeclStmts in map");
788    assert(!SyntheticDeclStmts.count(Synthetic) && "Already in map");
789    SyntheticDeclStmts[Synthetic] = Source;
790  }
791
792  typedef llvm::DenseMap<const DeclStmt *, const DeclStmt *>::const_iterator
793    synthetic_stmt_iterator;
794
795  /// Iterates over synthetic DeclStmts in the CFG.
796  ///
797  /// Each element is a (synthetic statement, source statement) pair.
798  ///
799  /// \sa addSyntheticDeclStmt
800  synthetic_stmt_iterator synthetic_stmt_begin() const {
801    return SyntheticDeclStmts.begin();
802  }
803
804  /// \sa synthetic_stmt_begin
805  synthetic_stmt_iterator synthetic_stmt_end() const {
806    return SyntheticDeclStmts.end();
807  }
808
809  //===--------------------------------------------------------------------===//
810  // Member templates useful for various batch operations over CFGs.
811  //===--------------------------------------------------------------------===//
812
813  template <typename CALLBACK>
814  void VisitBlockStmts(CALLBACK& O) const {
815    for (const_iterator I=begin(), E=end(); I != E; ++I)
816      for (CFGBlock::const_iterator BI=(*I)->begin(), BE=(*I)->end();
817           BI != BE; ++BI) {
818        if (Optional<CFGStmt> stmt = BI->getAs<CFGStmt>())
819          O(const_cast<Stmt*>(stmt->getStmt()));
820      }
821  }
822
823  //===--------------------------------------------------------------------===//
824  // CFG Introspection.
825  //===--------------------------------------------------------------------===//
826
827  /// getNumBlockIDs - Returns the total number of BlockIDs allocated (which
828  /// start at 0).
829  unsigned getNumBlockIDs() const { return NumBlockIDs; }
830
831  /// size - Return the total number of CFGBlocks within the CFG
832  /// This is simply a renaming of the getNumBlockIDs(). This is necessary
833  /// because the dominator implementation needs such an interface.
834  unsigned size() const { return NumBlockIDs; }
835
836  //===--------------------------------------------------------------------===//
837  // CFG Debugging: Pretty-Printing and Visualization.
838  //===--------------------------------------------------------------------===//
839
840  void viewCFG(const LangOptions &LO) const;
841  void print(raw_ostream &OS, const LangOptions &LO, bool ShowColors) const;
842  void dump(const LangOptions &LO, bool ShowColors) const;
843
844  //===--------------------------------------------------------------------===//
845  // Internal: constructors and data.
846  //===--------------------------------------------------------------------===//
847
848  CFG() : Entry(NULL), Exit(NULL), IndirectGotoBlock(NULL), NumBlockIDs(0),
849          Blocks(BlkBVC, 10) {}
850
851  llvm::BumpPtrAllocator& getAllocator() {
852    return BlkBVC.getAllocator();
853  }
854
855  BumpVectorContext &getBumpVectorContext() {
856    return BlkBVC;
857  }
858
859private:
860  CFGBlock *Entry;
861  CFGBlock *Exit;
862  CFGBlock* IndirectGotoBlock;  // Special block to contain collective dispatch
863                                // for indirect gotos
864  unsigned  NumBlockIDs;
865
866  BumpVectorContext BlkBVC;
867
868  CFGBlockListTy Blocks;
869
870  /// C++ 'try' statements are modeled with an indirect dispatch block.
871  /// This is the collection of such blocks present in the CFG.
872  std::vector<const CFGBlock *> TryDispatchBlocks;
873
874  /// Collects DeclStmts synthesized for this CFG and maps each one back to its
875  /// source DeclStmt.
876  llvm::DenseMap<const DeclStmt *, const DeclStmt *> SyntheticDeclStmts;
877};
878} // end namespace clang
879
880//===----------------------------------------------------------------------===//
881// GraphTraits specializations for CFG basic block graphs (source-level CFGs)
882//===----------------------------------------------------------------------===//
883
884namespace llvm {
885
886/// Implement simplify_type for CFGTerminator, so that we can dyn_cast from
887/// CFGTerminator to a specific Stmt class.
888template <> struct simplify_type< ::clang::CFGTerminator> {
889  typedef ::clang::Stmt *SimpleType;
890  static SimpleType getSimplifiedValue(::clang::CFGTerminator Val) {
891    return Val.getStmt();
892  }
893};
894
895// Traits for: CFGBlock
896
897template <> struct GraphTraits< ::clang::CFGBlock *> {
898  typedef ::clang::CFGBlock NodeType;
899  typedef ::clang::CFGBlock::succ_iterator ChildIteratorType;
900
901  static NodeType* getEntryNode(::clang::CFGBlock *BB)
902  { return BB; }
903
904  static inline ChildIteratorType child_begin(NodeType* N)
905  { return N->succ_begin(); }
906
907  static inline ChildIteratorType child_end(NodeType* N)
908  { return N->succ_end(); }
909};
910
911template <> struct GraphTraits< const ::clang::CFGBlock *> {
912  typedef const ::clang::CFGBlock NodeType;
913  typedef ::clang::CFGBlock::const_succ_iterator ChildIteratorType;
914
915  static NodeType* getEntryNode(const clang::CFGBlock *BB)
916  { return BB; }
917
918  static inline ChildIteratorType child_begin(NodeType* N)
919  { return N->succ_begin(); }
920
921  static inline ChildIteratorType child_end(NodeType* N)
922  { return N->succ_end(); }
923};
924
925template <> struct GraphTraits<Inverse< ::clang::CFGBlock*> > {
926  typedef ::clang::CFGBlock NodeType;
927  typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType;
928
929  static NodeType *getEntryNode(Inverse< ::clang::CFGBlock*> G)
930  { return G.Graph; }
931
932  static inline ChildIteratorType child_begin(NodeType* N)
933  { return N->pred_begin(); }
934
935  static inline ChildIteratorType child_end(NodeType* N)
936  { return N->pred_end(); }
937};
938
939template <> struct GraphTraits<Inverse<const ::clang::CFGBlock*> > {
940  typedef const ::clang::CFGBlock NodeType;
941  typedef ::clang::CFGBlock::const_pred_iterator ChildIteratorType;
942
943  static NodeType *getEntryNode(Inverse<const ::clang::CFGBlock*> G)
944  { return G.Graph; }
945
946  static inline ChildIteratorType child_begin(NodeType* N)
947  { return N->pred_begin(); }
948
949  static inline ChildIteratorType child_end(NodeType* N)
950  { return N->pred_end(); }
951};
952
953// Traits for: CFG
954
955template <> struct GraphTraits< ::clang::CFG* >
956    : public GraphTraits< ::clang::CFGBlock *>  {
957
958  typedef ::clang::CFG::graph_iterator nodes_iterator;
959
960  static NodeType     *getEntryNode(::clang::CFG* F) { return &F->getEntry(); }
961  static nodes_iterator nodes_begin(::clang::CFG* F) { return F->nodes_begin();}
962  static nodes_iterator   nodes_end(::clang::CFG* F) { return F->nodes_end(); }
963  static unsigned              size(::clang::CFG* F) { return F->size(); }
964};
965
966template <> struct GraphTraits<const ::clang::CFG* >
967    : public GraphTraits<const ::clang::CFGBlock *>  {
968
969  typedef ::clang::CFG::const_graph_iterator nodes_iterator;
970
971  static NodeType *getEntryNode( const ::clang::CFG* F) {
972    return &F->getEntry();
973  }
974  static nodes_iterator nodes_begin( const ::clang::CFG* F) {
975    return F->nodes_begin();
976  }
977  static nodes_iterator nodes_end( const ::clang::CFG* F) {
978    return F->nodes_end();
979  }
980  static unsigned size(const ::clang::CFG* F) {
981    return F->size();
982  }
983};
984
985template <> struct GraphTraits<Inverse< ::clang::CFG*> >
986  : public GraphTraits<Inverse< ::clang::CFGBlock*> > {
987
988  typedef ::clang::CFG::graph_iterator nodes_iterator;
989
990  static NodeType *getEntryNode( ::clang::CFG* F) { return &F->getExit(); }
991  static nodes_iterator nodes_begin( ::clang::CFG* F) {return F->nodes_begin();}
992  static nodes_iterator nodes_end( ::clang::CFG* F) { return F->nodes_end(); }
993};
994
995template <> struct GraphTraits<Inverse<const ::clang::CFG*> >
996  : public GraphTraits<Inverse<const ::clang::CFGBlock*> > {
997
998  typedef ::clang::CFG::const_graph_iterator nodes_iterator;
999
1000  static NodeType *getEntryNode(const ::clang::CFG* F) { return &F->getExit(); }
1001  static nodes_iterator nodes_begin(const ::clang::CFG* F) {
1002    return F->nodes_begin();
1003  }
1004  static nodes_iterator nodes_end(const ::clang::CFG* F) {
1005    return F->nodes_end();
1006  }
1007};
1008} // end llvm namespace
1009#endif
1010