1//===-- llvm/ADT/FoldingSet.h - Uniquing Hash Set ---------------*- 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 a hash set that can be used to remove duplication of nodes
11// in a graph.  This code was originally created by Chris Lattner for use with
12// SelectionDAGCSEMap, but was isolated to provide use across the llvm code set.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_ADT_FOLDINGSET_H
17#define LLVM_ADT_FOLDINGSET_H
18
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/ADT/StringRef.h"
21#include "llvm/Support/Allocator.h"
22#include "llvm/Support/DataTypes.h"
23
24namespace llvm {
25  class APFloat;
26  class APInt;
27
28/// This folding set used for two purposes:
29///   1. Given information about a node we want to create, look up the unique
30///      instance of the node in the set.  If the node already exists, return
31///      it, otherwise return the bucket it should be inserted into.
32///   2. Given a node that has already been created, remove it from the set.
33///
34/// This class is implemented as a single-link chained hash table, where the
35/// "buckets" are actually the nodes themselves (the next pointer is in the
36/// node).  The last node points back to the bucket to simplify node removal.
37///
38/// Any node that is to be included in the folding set must be a subclass of
39/// FoldingSetNode.  The node class must also define a Profile method used to
40/// establish the unique bits of data for the node.  The Profile method is
41/// passed a FoldingSetNodeID object which is used to gather the bits.  Just
42/// call one of the Add* functions defined in the FoldingSetImpl::NodeID class.
43/// NOTE: That the folding set does not own the nodes and it is the
44/// responsibility of the user to dispose of the nodes.
45///
46/// Eg.
47///    class MyNode : public FoldingSetNode {
48///    private:
49///      std::string Name;
50///      unsigned Value;
51///    public:
52///      MyNode(const char *N, unsigned V) : Name(N), Value(V) {}
53///       ...
54///      void Profile(FoldingSetNodeID &ID) const {
55///        ID.AddString(Name);
56///        ID.AddInteger(Value);
57///      }
58///      ...
59///    };
60///
61/// To define the folding set itself use the FoldingSet template;
62///
63/// Eg.
64///    FoldingSet<MyNode> MyFoldingSet;
65///
66/// Four public methods are available to manipulate the folding set;
67///
68/// 1) If you have an existing node that you want add to the set but unsure
69/// that the node might already exist then call;
70///
71///    MyNode *M = MyFoldingSet.GetOrInsertNode(N);
72///
73/// If The result is equal to the input then the node has been inserted.
74/// Otherwise, the result is the node existing in the folding set, and the
75/// input can be discarded (use the result instead.)
76///
77/// 2) If you are ready to construct a node but want to check if it already
78/// exists, then call FindNodeOrInsertPos with a FoldingSetNodeID of the bits to
79/// check;
80///
81///   FoldingSetNodeID ID;
82///   ID.AddString(Name);
83///   ID.AddInteger(Value);
84///   void *InsertPoint;
85///
86///    MyNode *M = MyFoldingSet.FindNodeOrInsertPos(ID, InsertPoint);
87///
88/// If found then M with be non-NULL, else InsertPoint will point to where it
89/// should be inserted using InsertNode.
90///
91/// 3) If you get a NULL result from FindNodeOrInsertPos then you can as a new
92/// node with FindNodeOrInsertPos;
93///
94///    InsertNode(N, InsertPoint);
95///
96/// 4) Finally, if you want to remove a node from the folding set call;
97///
98///    bool WasRemoved = RemoveNode(N);
99///
100/// The result indicates whether the node existed in the folding set.
101
102class FoldingSetNodeID;
103
104//===----------------------------------------------------------------------===//
105/// FoldingSetImpl - Implements the folding set functionality.  The main
106/// structure is an array of buckets.  Each bucket is indexed by the hash of
107/// the nodes it contains.  The bucket itself points to the nodes contained
108/// in the bucket via a singly linked list.  The last node in the list points
109/// back to the bucket to facilitate node removal.
110///
111class FoldingSetImpl {
112protected:
113  /// Buckets - Array of bucket chains.
114  ///
115  void **Buckets;
116
117  /// NumBuckets - Length of the Buckets array.  Always a power of 2.
118  ///
119  unsigned NumBuckets;
120
121  /// NumNodes - Number of nodes in the folding set. Growth occurs when NumNodes
122  /// is greater than twice the number of buckets.
123  unsigned NumNodes;
124
125public:
126  explicit FoldingSetImpl(unsigned Log2InitSize = 6);
127  virtual ~FoldingSetImpl();
128
129  //===--------------------------------------------------------------------===//
130  /// Node - This class is used to maintain the singly linked bucket list in
131  /// a folding set.
132  ///
133  class Node {
134  private:
135    // NextInFoldingSetBucket - next link in the bucket list.
136    void *NextInFoldingSetBucket;
137
138  public:
139
140    Node() : NextInFoldingSetBucket(nullptr) {}
141
142    // Accessors
143    void *getNextInBucket() const { return NextInFoldingSetBucket; }
144    void SetNextInBucket(void *N) { NextInFoldingSetBucket = N; }
145  };
146
147  /// clear - Remove all nodes from the folding set.
148  void clear();
149
150  /// RemoveNode - Remove a node from the folding set, returning true if one
151  /// was removed or false if the node was not in the folding set.
152  bool RemoveNode(Node *N);
153
154  /// GetOrInsertNode - If there is an existing simple Node exactly
155  /// equal to the specified node, return it.  Otherwise, insert 'N' and return
156  /// it instead.
157  Node *GetOrInsertNode(Node *N);
158
159  /// FindNodeOrInsertPos - Look up the node specified by ID.  If it exists,
160  /// return it.  If not, return the insertion token that will make insertion
161  /// faster.
162  Node *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos);
163
164  /// InsertNode - Insert the specified node into the folding set, knowing that
165  /// it is not already in the folding set.  InsertPos must be obtained from
166  /// FindNodeOrInsertPos.
167  void InsertNode(Node *N, void *InsertPos);
168
169  /// InsertNode - Insert the specified node into the folding set, knowing that
170  /// it is not already in the folding set.
171  void InsertNode(Node *N) {
172    Node *Inserted = GetOrInsertNode(N);
173    (void)Inserted;
174    assert(Inserted == N && "Node already inserted!");
175  }
176
177  /// size - Returns the number of nodes in the folding set.
178  unsigned size() const { return NumNodes; }
179
180  /// empty - Returns true if there are no nodes in the folding set.
181  bool empty() const { return NumNodes == 0; }
182
183private:
184
185  /// GrowHashTable - Double the size of the hash table and rehash everything.
186  ///
187  void GrowHashTable();
188
189protected:
190
191  /// GetNodeProfile - Instantiations of the FoldingSet template implement
192  /// this function to gather data bits for the given node.
193  virtual void GetNodeProfile(Node *N, FoldingSetNodeID &ID) const = 0;
194  /// NodeEquals - Instantiations of the FoldingSet template implement
195  /// this function to compare the given node with the given ID.
196  virtual bool NodeEquals(Node *N, const FoldingSetNodeID &ID, unsigned IDHash,
197                          FoldingSetNodeID &TempID) const=0;
198  /// ComputeNodeHash - Instantiations of the FoldingSet template implement
199  /// this function to compute a hash value for the given node.
200  virtual unsigned ComputeNodeHash(Node *N, FoldingSetNodeID &TempID) const = 0;
201};
202
203//===----------------------------------------------------------------------===//
204
205template<typename T> struct FoldingSetTrait;
206
207/// DefaultFoldingSetTrait - This class provides default implementations
208/// for FoldingSetTrait implementations.
209///
210template<typename T> struct DefaultFoldingSetTrait {
211  static void Profile(const T &X, FoldingSetNodeID &ID) {
212    X.Profile(ID);
213  }
214  static void Profile(T &X, FoldingSetNodeID &ID) {
215    X.Profile(ID);
216  }
217
218  // Equals - Test if the profile for X would match ID, using TempID
219  // to compute a temporary ID if necessary. The default implementation
220  // just calls Profile and does a regular comparison. Implementations
221  // can override this to provide more efficient implementations.
222  static inline bool Equals(T &X, const FoldingSetNodeID &ID, unsigned IDHash,
223                            FoldingSetNodeID &TempID);
224
225  // ComputeHash - Compute a hash value for X, using TempID to
226  // compute a temporary ID if necessary. The default implementation
227  // just calls Profile and does a regular hash computation.
228  // Implementations can override this to provide more efficient
229  // implementations.
230  static inline unsigned ComputeHash(T &X, FoldingSetNodeID &TempID);
231};
232
233/// FoldingSetTrait - This trait class is used to define behavior of how
234/// to "profile" (in the FoldingSet parlance) an object of a given type.
235/// The default behavior is to invoke a 'Profile' method on an object, but
236/// through template specialization the behavior can be tailored for specific
237/// types.  Combined with the FoldingSetNodeWrapper class, one can add objects
238/// to FoldingSets that were not originally designed to have that behavior.
239template<typename T> struct FoldingSetTrait
240  : public DefaultFoldingSetTrait<T> {};
241
242template<typename T, typename Ctx> struct ContextualFoldingSetTrait;
243
244/// DefaultContextualFoldingSetTrait - Like DefaultFoldingSetTrait, but
245/// for ContextualFoldingSets.
246template<typename T, typename Ctx>
247struct DefaultContextualFoldingSetTrait {
248  static void Profile(T &X, FoldingSetNodeID &ID, Ctx Context) {
249    X.Profile(ID, Context);
250  }
251  static inline bool Equals(T &X, const FoldingSetNodeID &ID, unsigned IDHash,
252                            FoldingSetNodeID &TempID, Ctx Context);
253  static inline unsigned ComputeHash(T &X, FoldingSetNodeID &TempID,
254                                     Ctx Context);
255};
256
257/// ContextualFoldingSetTrait - Like FoldingSetTrait, but for
258/// ContextualFoldingSets.
259template<typename T, typename Ctx> struct ContextualFoldingSetTrait
260  : public DefaultContextualFoldingSetTrait<T, Ctx> {};
261
262//===--------------------------------------------------------------------===//
263/// FoldingSetNodeIDRef - This class describes a reference to an interned
264/// FoldingSetNodeID, which can be a useful to store node id data rather
265/// than using plain FoldingSetNodeIDs, since the 32-element SmallVector
266/// is often much larger than necessary, and the possibility of heap
267/// allocation means it requires a non-trivial destructor call.
268class FoldingSetNodeIDRef {
269  const unsigned *Data;
270  size_t Size;
271public:
272  FoldingSetNodeIDRef() : Data(nullptr), Size(0) {}
273  FoldingSetNodeIDRef(const unsigned *D, size_t S) : Data(D), Size(S) {}
274
275  /// ComputeHash - Compute a strong hash value for this FoldingSetNodeIDRef,
276  /// used to lookup the node in the FoldingSetImpl.
277  unsigned ComputeHash() const;
278
279  bool operator==(FoldingSetNodeIDRef) const;
280
281  bool operator!=(FoldingSetNodeIDRef RHS) const { return !(*this == RHS); }
282
283  /// Used to compare the "ordering" of two nodes as defined by the
284  /// profiled bits and their ordering defined by memcmp().
285  bool operator<(FoldingSetNodeIDRef) const;
286
287  const unsigned *getData() const { return Data; }
288  size_t getSize() const { return Size; }
289};
290
291//===--------------------------------------------------------------------===//
292/// FoldingSetNodeID - This class is used to gather all the unique data bits of
293/// a node.  When all the bits are gathered this class is used to produce a
294/// hash value for the node.
295///
296class FoldingSetNodeID {
297  /// Bits - Vector of all the data bits that make the node unique.
298  /// Use a SmallVector to avoid a heap allocation in the common case.
299  SmallVector<unsigned, 32> Bits;
300
301public:
302  FoldingSetNodeID() {}
303
304  FoldingSetNodeID(FoldingSetNodeIDRef Ref)
305    : Bits(Ref.getData(), Ref.getData() + Ref.getSize()) {}
306
307  /// Add* - Add various data types to Bit data.
308  ///
309  void AddPointer(const void *Ptr);
310  void AddInteger(signed I);
311  void AddInteger(unsigned I);
312  void AddInteger(long I);
313  void AddInteger(unsigned long I);
314  void AddInteger(long long I);
315  void AddInteger(unsigned long long I);
316  void AddBoolean(bool B) { AddInteger(B ? 1U : 0U); }
317  void AddString(StringRef String);
318  void AddNodeID(const FoldingSetNodeID &ID);
319
320  template <typename T>
321  inline void Add(const T &x) { FoldingSetTrait<T>::Profile(x, *this); }
322
323  /// clear - Clear the accumulated profile, allowing this FoldingSetNodeID
324  /// object to be used to compute a new profile.
325  inline void clear() { Bits.clear(); }
326
327  /// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used
328  /// to lookup the node in the FoldingSetImpl.
329  unsigned ComputeHash() const;
330
331  /// operator== - Used to compare two nodes to each other.
332  ///
333  bool operator==(const FoldingSetNodeID &RHS) const;
334  bool operator==(const FoldingSetNodeIDRef RHS) const;
335
336  bool operator!=(const FoldingSetNodeID &RHS) const { return !(*this == RHS); }
337  bool operator!=(const FoldingSetNodeIDRef RHS) const { return !(*this ==RHS);}
338
339  /// Used to compare the "ordering" of two nodes as defined by the
340  /// profiled bits and their ordering defined by memcmp().
341  bool operator<(const FoldingSetNodeID &RHS) const;
342  bool operator<(const FoldingSetNodeIDRef RHS) const;
343
344  /// Intern - Copy this node's data to a memory region allocated from the
345  /// given allocator and return a FoldingSetNodeIDRef describing the
346  /// interned data.
347  FoldingSetNodeIDRef Intern(BumpPtrAllocator &Allocator) const;
348};
349
350// Convenience type to hide the implementation of the folding set.
351typedef FoldingSetImpl::Node FoldingSetNode;
352template<class T> class FoldingSetIterator;
353template<class T> class FoldingSetBucketIterator;
354
355// Definitions of FoldingSetTrait and ContextualFoldingSetTrait functions, which
356// require the definition of FoldingSetNodeID.
357template<typename T>
358inline bool
359DefaultFoldingSetTrait<T>::Equals(T &X, const FoldingSetNodeID &ID,
360                                  unsigned /*IDHash*/,
361                                  FoldingSetNodeID &TempID) {
362  FoldingSetTrait<T>::Profile(X, TempID);
363  return TempID == ID;
364}
365template<typename T>
366inline unsigned
367DefaultFoldingSetTrait<T>::ComputeHash(T &X, FoldingSetNodeID &TempID) {
368  FoldingSetTrait<T>::Profile(X, TempID);
369  return TempID.ComputeHash();
370}
371template<typename T, typename Ctx>
372inline bool
373DefaultContextualFoldingSetTrait<T, Ctx>::Equals(T &X,
374                                                 const FoldingSetNodeID &ID,
375                                                 unsigned /*IDHash*/,
376                                                 FoldingSetNodeID &TempID,
377                                                 Ctx Context) {
378  ContextualFoldingSetTrait<T, Ctx>::Profile(X, TempID, Context);
379  return TempID == ID;
380}
381template<typename T, typename Ctx>
382inline unsigned
383DefaultContextualFoldingSetTrait<T, Ctx>::ComputeHash(T &X,
384                                                      FoldingSetNodeID &TempID,
385                                                      Ctx Context) {
386  ContextualFoldingSetTrait<T, Ctx>::Profile(X, TempID, Context);
387  return TempID.ComputeHash();
388}
389
390//===----------------------------------------------------------------------===//
391/// FoldingSet - This template class is used to instantiate a specialized
392/// implementation of the folding set to the node class T.  T must be a
393/// subclass of FoldingSetNode and implement a Profile function.
394///
395template<class T> class FoldingSet : public FoldingSetImpl {
396private:
397  /// GetNodeProfile - Each instantiatation of the FoldingSet needs to provide a
398  /// way to convert nodes into a unique specifier.
399  void GetNodeProfile(Node *N, FoldingSetNodeID &ID) const override {
400    T *TN = static_cast<T *>(N);
401    FoldingSetTrait<T>::Profile(*TN, ID);
402  }
403  /// NodeEquals - Instantiations may optionally provide a way to compare a
404  /// node with a specified ID.
405  bool NodeEquals(Node *N, const FoldingSetNodeID &ID, unsigned IDHash,
406                  FoldingSetNodeID &TempID) const override {
407    T *TN = static_cast<T *>(N);
408    return FoldingSetTrait<T>::Equals(*TN, ID, IDHash, TempID);
409  }
410  /// ComputeNodeHash - Instantiations may optionally provide a way to compute a
411  /// hash value directly from a node.
412  unsigned ComputeNodeHash(Node *N, FoldingSetNodeID &TempID) const override {
413    T *TN = static_cast<T *>(N);
414    return FoldingSetTrait<T>::ComputeHash(*TN, TempID);
415  }
416
417public:
418  explicit FoldingSet(unsigned Log2InitSize = 6)
419  : FoldingSetImpl(Log2InitSize)
420  {}
421
422  typedef FoldingSetIterator<T> iterator;
423  iterator begin() { return iterator(Buckets); }
424  iterator end() { return iterator(Buckets+NumBuckets); }
425
426  typedef FoldingSetIterator<const T> const_iterator;
427  const_iterator begin() const { return const_iterator(Buckets); }
428  const_iterator end() const { return const_iterator(Buckets+NumBuckets); }
429
430  typedef FoldingSetBucketIterator<T> bucket_iterator;
431
432  bucket_iterator bucket_begin(unsigned hash) {
433    return bucket_iterator(Buckets + (hash & (NumBuckets-1)));
434  }
435
436  bucket_iterator bucket_end(unsigned hash) {
437    return bucket_iterator(Buckets + (hash & (NumBuckets-1)), true);
438  }
439
440  /// GetOrInsertNode - If there is an existing simple Node exactly
441  /// equal to the specified node, return it.  Otherwise, insert 'N' and
442  /// return it instead.
443  T *GetOrInsertNode(Node *N) {
444    return static_cast<T *>(FoldingSetImpl::GetOrInsertNode(N));
445  }
446
447  /// FindNodeOrInsertPos - Look up the node specified by ID.  If it exists,
448  /// return it.  If not, return the insertion token that will make insertion
449  /// faster.
450  T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) {
451    return static_cast<T *>(FoldingSetImpl::FindNodeOrInsertPos(ID, InsertPos));
452  }
453};
454
455//===----------------------------------------------------------------------===//
456/// ContextualFoldingSet - This template class is a further refinement
457/// of FoldingSet which provides a context argument when calling
458/// Profile on its nodes.  Currently, that argument is fixed at
459/// initialization time.
460///
461/// T must be a subclass of FoldingSetNode and implement a Profile
462/// function with signature
463///   void Profile(llvm::FoldingSetNodeID &, Ctx);
464template <class T, class Ctx>
465class ContextualFoldingSet : public FoldingSetImpl {
466  // Unfortunately, this can't derive from FoldingSet<T> because the
467  // construction vtable for FoldingSet<T> requires
468  // FoldingSet<T>::GetNodeProfile to be instantiated, which in turn
469  // requires a single-argument T::Profile().
470
471private:
472  Ctx Context;
473
474  /// GetNodeProfile - Each instantiatation of the FoldingSet needs to provide a
475  /// way to convert nodes into a unique specifier.
476  void GetNodeProfile(FoldingSetImpl::Node *N,
477                      FoldingSetNodeID &ID) const override {
478    T *TN = static_cast<T *>(N);
479    ContextualFoldingSetTrait<T, Ctx>::Profile(*TN, ID, Context);
480  }
481  bool NodeEquals(FoldingSetImpl::Node *N, const FoldingSetNodeID &ID,
482                  unsigned IDHash, FoldingSetNodeID &TempID) const override {
483    T *TN = static_cast<T *>(N);
484    return ContextualFoldingSetTrait<T, Ctx>::Equals(*TN, ID, IDHash, TempID,
485                                                     Context);
486  }
487  unsigned ComputeNodeHash(FoldingSetImpl::Node *N,
488                           FoldingSetNodeID &TempID) const override {
489    T *TN = static_cast<T *>(N);
490    return ContextualFoldingSetTrait<T, Ctx>::ComputeHash(*TN, TempID, Context);
491  }
492
493public:
494  explicit ContextualFoldingSet(Ctx Context, unsigned Log2InitSize = 6)
495  : FoldingSetImpl(Log2InitSize), Context(Context)
496  {}
497
498  Ctx getContext() const { return Context; }
499
500
501  typedef FoldingSetIterator<T> iterator;
502  iterator begin() { return iterator(Buckets); }
503  iterator end() { return iterator(Buckets+NumBuckets); }
504
505  typedef FoldingSetIterator<const T> const_iterator;
506  const_iterator begin() const { return const_iterator(Buckets); }
507  const_iterator end() const { return const_iterator(Buckets+NumBuckets); }
508
509  typedef FoldingSetBucketIterator<T> bucket_iterator;
510
511  bucket_iterator bucket_begin(unsigned hash) {
512    return bucket_iterator(Buckets + (hash & (NumBuckets-1)));
513  }
514
515  bucket_iterator bucket_end(unsigned hash) {
516    return bucket_iterator(Buckets + (hash & (NumBuckets-1)), true);
517  }
518
519  /// GetOrInsertNode - If there is an existing simple Node exactly
520  /// equal to the specified node, return it.  Otherwise, insert 'N'
521  /// and return it instead.
522  T *GetOrInsertNode(Node *N) {
523    return static_cast<T *>(FoldingSetImpl::GetOrInsertNode(N));
524  }
525
526  /// FindNodeOrInsertPos - Look up the node specified by ID.  If it
527  /// exists, return it.  If not, return the insertion token that will
528  /// make insertion faster.
529  T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) {
530    return static_cast<T *>(FoldingSetImpl::FindNodeOrInsertPos(ID, InsertPos));
531  }
532};
533
534//===----------------------------------------------------------------------===//
535/// FoldingSetVectorIterator - This implements an iterator for
536/// FoldingSetVector. It is only necessary because FoldingSetIterator provides
537/// a value_type of T, while the vector in FoldingSetVector exposes
538/// a value_type of T*. Fortunately, FoldingSetIterator doesn't expose very
539/// much besides operator* and operator->, so we just wrap the inner vector
540/// iterator and perform the extra dereference.
541template <class T, class VectorIteratorT>
542class FoldingSetVectorIterator {
543  // Provide a typedef to workaround the lack of correct injected class name
544  // support in older GCCs.
545  typedef FoldingSetVectorIterator<T, VectorIteratorT> SelfT;
546
547  VectorIteratorT Iterator;
548
549public:
550  FoldingSetVectorIterator(VectorIteratorT I) : Iterator(I) {}
551
552  bool operator==(const SelfT &RHS) const {
553    return Iterator == RHS.Iterator;
554  }
555  bool operator!=(const SelfT &RHS) const {
556    return Iterator != RHS.Iterator;
557  }
558
559  T &operator*() const { return **Iterator; }
560
561  T *operator->() const { return *Iterator; }
562
563  inline SelfT &operator++() {
564    ++Iterator;
565    return *this;
566  }
567  SelfT operator++(int) {
568    SelfT tmp = *this;
569    ++*this;
570    return tmp;
571  }
572};
573
574//===----------------------------------------------------------------------===//
575/// FoldingSetVector - This template class combines a FoldingSet and a vector
576/// to provide the interface of FoldingSet but with deterministic iteration
577/// order based on the insertion order. T must be a subclass of FoldingSetNode
578/// and implement a Profile function.
579template <class T, class VectorT = SmallVector<T*, 8> >
580class FoldingSetVector {
581  FoldingSet<T> Set;
582  VectorT Vector;
583
584public:
585  explicit FoldingSetVector(unsigned Log2InitSize = 6)
586      : Set(Log2InitSize) {
587  }
588
589  typedef FoldingSetVectorIterator<T, typename VectorT::iterator> iterator;
590  iterator begin() { return Vector.begin(); }
591  iterator end()   { return Vector.end(); }
592
593  typedef FoldingSetVectorIterator<const T, typename VectorT::const_iterator>
594    const_iterator;
595  const_iterator begin() const { return Vector.begin(); }
596  const_iterator end()   const { return Vector.end(); }
597
598  /// clear - Remove all nodes from the folding set.
599  void clear() { Set.clear(); Vector.clear(); }
600
601  /// FindNodeOrInsertPos - Look up the node specified by ID.  If it exists,
602  /// return it.  If not, return the insertion token that will make insertion
603  /// faster.
604  T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) {
605    return Set.FindNodeOrInsertPos(ID, InsertPos);
606  }
607
608  /// GetOrInsertNode - If there is an existing simple Node exactly
609  /// equal to the specified node, return it.  Otherwise, insert 'N' and
610  /// return it instead.
611  T *GetOrInsertNode(T *N) {
612    T *Result = Set.GetOrInsertNode(N);
613    if (Result == N) Vector.push_back(N);
614    return Result;
615  }
616
617  /// InsertNode - Insert the specified node into the folding set, knowing that
618  /// it is not already in the folding set.  InsertPos must be obtained from
619  /// FindNodeOrInsertPos.
620  void InsertNode(T *N, void *InsertPos) {
621    Set.InsertNode(N, InsertPos);
622    Vector.push_back(N);
623  }
624
625  /// InsertNode - Insert the specified node into the folding set, knowing that
626  /// it is not already in the folding set.
627  void InsertNode(T *N) {
628    Set.InsertNode(N);
629    Vector.push_back(N);
630  }
631
632  /// size - Returns the number of nodes in the folding set.
633  unsigned size() const { return Set.size(); }
634
635  /// empty - Returns true if there are no nodes in the folding set.
636  bool empty() const { return Set.empty(); }
637};
638
639//===----------------------------------------------------------------------===//
640/// FoldingSetIteratorImpl - This is the common iterator support shared by all
641/// folding sets, which knows how to walk the folding set hash table.
642class FoldingSetIteratorImpl {
643protected:
644  FoldingSetNode *NodePtr;
645  FoldingSetIteratorImpl(void **Bucket);
646  void advance();
647
648public:
649  bool operator==(const FoldingSetIteratorImpl &RHS) const {
650    return NodePtr == RHS.NodePtr;
651  }
652  bool operator!=(const FoldingSetIteratorImpl &RHS) const {
653    return NodePtr != RHS.NodePtr;
654  }
655};
656
657
658template<class T>
659class FoldingSetIterator : public FoldingSetIteratorImpl {
660public:
661  explicit FoldingSetIterator(void **Bucket) : FoldingSetIteratorImpl(Bucket) {}
662
663  T &operator*() const {
664    return *static_cast<T*>(NodePtr);
665  }
666
667  T *operator->() const {
668    return static_cast<T*>(NodePtr);
669  }
670
671  inline FoldingSetIterator &operator++() {          // Preincrement
672    advance();
673    return *this;
674  }
675  FoldingSetIterator operator++(int) {        // Postincrement
676    FoldingSetIterator tmp = *this; ++*this; return tmp;
677  }
678};
679
680//===----------------------------------------------------------------------===//
681/// FoldingSetBucketIteratorImpl - This is the common bucket iterator support
682/// shared by all folding sets, which knows how to walk a particular bucket
683/// of a folding set hash table.
684
685class FoldingSetBucketIteratorImpl {
686protected:
687  void *Ptr;
688
689  explicit FoldingSetBucketIteratorImpl(void **Bucket);
690
691  FoldingSetBucketIteratorImpl(void **Bucket, bool)
692    : Ptr(Bucket) {}
693
694  void advance() {
695    void *Probe = static_cast<FoldingSetNode*>(Ptr)->getNextInBucket();
696    uintptr_t x = reinterpret_cast<uintptr_t>(Probe) & ~0x1;
697    Ptr = reinterpret_cast<void*>(x);
698  }
699
700public:
701  bool operator==(const FoldingSetBucketIteratorImpl &RHS) const {
702    return Ptr == RHS.Ptr;
703  }
704  bool operator!=(const FoldingSetBucketIteratorImpl &RHS) const {
705    return Ptr != RHS.Ptr;
706  }
707};
708
709
710template<class T>
711class FoldingSetBucketIterator : public FoldingSetBucketIteratorImpl {
712public:
713  explicit FoldingSetBucketIterator(void **Bucket) :
714    FoldingSetBucketIteratorImpl(Bucket) {}
715
716  FoldingSetBucketIterator(void **Bucket, bool) :
717    FoldingSetBucketIteratorImpl(Bucket, true) {}
718
719  T &operator*() const { return *static_cast<T*>(Ptr); }
720  T *operator->() const { return static_cast<T*>(Ptr); }
721
722  inline FoldingSetBucketIterator &operator++() { // Preincrement
723    advance();
724    return *this;
725  }
726  FoldingSetBucketIterator operator++(int) {      // Postincrement
727    FoldingSetBucketIterator tmp = *this; ++*this; return tmp;
728  }
729};
730
731//===----------------------------------------------------------------------===//
732/// FoldingSetNodeWrapper - This template class is used to "wrap" arbitrary
733/// types in an enclosing object so that they can be inserted into FoldingSets.
734template <typename T>
735class FoldingSetNodeWrapper : public FoldingSetNode {
736  T data;
737public:
738  explicit FoldingSetNodeWrapper(const T &x) : data(x) {}
739  virtual ~FoldingSetNodeWrapper() {}
740
741  template<typename A1>
742  explicit FoldingSetNodeWrapper(const A1 &a1)
743    : data(a1) {}
744
745  template <typename A1, typename A2>
746  explicit FoldingSetNodeWrapper(const A1 &a1, const A2 &a2)
747    : data(a1,a2) {}
748
749  template <typename A1, typename A2, typename A3>
750  explicit FoldingSetNodeWrapper(const A1 &a1, const A2 &a2, const A3 &a3)
751    : data(a1,a2,a3) {}
752
753  template <typename A1, typename A2, typename A3, typename A4>
754  explicit FoldingSetNodeWrapper(const A1 &a1, const A2 &a2, const A3 &a3,
755                                 const A4 &a4)
756    : data(a1,a2,a3,a4) {}
757
758  template <typename A1, typename A2, typename A3, typename A4, typename A5>
759  explicit FoldingSetNodeWrapper(const A1 &a1, const A2 &a2, const A3 &a3,
760                                 const A4 &a4, const A5 &a5)
761  : data(a1,a2,a3,a4,a5) {}
762
763
764  void Profile(FoldingSetNodeID &ID) { FoldingSetTrait<T>::Profile(data, ID); }
765
766  T &getValue() { return data; }
767  const T &getValue() const { return data; }
768
769  operator T&() { return data; }
770  operator const T&() const { return data; }
771};
772
773//===----------------------------------------------------------------------===//
774/// FastFoldingSetNode - This is a subclass of FoldingSetNode which stores
775/// a FoldingSetNodeID value rather than requiring the node to recompute it
776/// each time it is needed. This trades space for speed (which can be
777/// significant if the ID is long), and it also permits nodes to drop
778/// information that would otherwise only be required for recomputing an ID.
779class FastFoldingSetNode : public FoldingSetNode {
780  FoldingSetNodeID FastID;
781protected:
782  explicit FastFoldingSetNode(const FoldingSetNodeID &ID) : FastID(ID) {}
783public:
784  void Profile(FoldingSetNodeID &ID) const {
785    ID.AddNodeID(FastID);
786  }
787};
788
789//===----------------------------------------------------------------------===//
790// Partial specializations of FoldingSetTrait.
791
792template<typename T> struct FoldingSetTrait<T*> {
793  static inline void Profile(T *X, FoldingSetNodeID &ID) {
794    ID.AddPointer(X);
795  }
796};
797template <typename T1, typename T2>
798struct FoldingSetTrait<std::pair<T1, T2>> {
799  static inline void Profile(const std::pair<T1, T2> &P,
800                             llvm::FoldingSetNodeID &ID) {
801    ID.Add(P.first);
802    ID.Add(P.second);
803  }
804};
805} // End of namespace llvm.
806
807#endif
808