1//===- llvm/ADT/ValueMap.h - Safe map from Values to data -------*- 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 ValueMap class.  ValueMap maps Value* or any subclass
11// to an arbitrary other type.  It provides the DenseMap interface but updates
12// itself to remain safe when keys are RAUWed or deleted.  By default, when a
13// key is RAUWed from V1 to V2, the old mapping V1->target is removed, and a new
14// mapping V2->target is added.  If V2 already existed, its old target is
15// overwritten.  When a key is deleted, its mapping is removed.
16//
17// You can override a ValueMap's Config parameter to control exactly what
18// happens on RAUW and destruction and to get called back on each event.  It's
19// legal to call back into the ValueMap from a Config's callbacks.  Config
20// parameters should inherit from ValueMapConfig<KeyT> to get default
21// implementations of all the methods ValueMap uses.  See ValueMapConfig for
22// documentation of the functions you can override.
23//
24//===----------------------------------------------------------------------===//
25
26#ifndef LLVM_ADT_VALUEMAP_H
27#define LLVM_ADT_VALUEMAP_H
28
29#include "llvm/ADT/DenseMap.h"
30#include "llvm/Support/Mutex.h"
31#include "llvm/Support/ValueHandle.h"
32#include "llvm/Support/type_traits.h"
33#include <iterator>
34
35namespace llvm {
36
37template<typename KeyT, typename ValueT, typename Config>
38class ValueMapCallbackVH;
39
40template<typename DenseMapT, typename KeyT>
41class ValueMapIterator;
42template<typename DenseMapT, typename KeyT>
43class ValueMapConstIterator;
44
45/// This class defines the default behavior for configurable aspects of
46/// ValueMap<>.  User Configs should inherit from this class to be as compatible
47/// as possible with future versions of ValueMap.
48template<typename KeyT>
49struct ValueMapConfig {
50  /// If FollowRAUW is true, the ValueMap will update mappings on RAUW. If it's
51  /// false, the ValueMap will leave the original mapping in place.
52  enum { FollowRAUW = true };
53
54  // All methods will be called with a first argument of type ExtraData.  The
55  // default implementations in this class take a templated first argument so
56  // that users' subclasses can use any type they want without having to
57  // override all the defaults.
58  struct ExtraData {};
59
60  template<typename ExtraDataT>
61  static void onRAUW(const ExtraDataT & /*Data*/, KeyT /*Old*/, KeyT /*New*/) {}
62  template<typename ExtraDataT>
63  static void onDelete(const ExtraDataT &/*Data*/, KeyT /*Old*/) {}
64
65  /// Returns a mutex that should be acquired around any changes to the map.
66  /// This is only acquired from the CallbackVH (and held around calls to onRAUW
67  /// and onDelete) and not inside other ValueMap methods.  NULL means that no
68  /// mutex is necessary.
69  template<typename ExtraDataT>
70  static sys::Mutex *getMutex(const ExtraDataT &/*Data*/) { return NULL; }
71};
72
73/// See the file comment.
74template<typename KeyT, typename ValueT, typename Config =ValueMapConfig<KeyT> >
75class ValueMap {
76  friend class ValueMapCallbackVH<KeyT, ValueT, Config>;
77  typedef ValueMapCallbackVH<KeyT, ValueT, Config> ValueMapCVH;
78  typedef DenseMap<ValueMapCVH, ValueT, DenseMapInfo<ValueMapCVH> > MapT;
79  typedef typename Config::ExtraData ExtraData;
80  MapT Map;
81  ExtraData Data;
82  ValueMap(const ValueMap&) LLVM_DELETED_FUNCTION;
83  ValueMap& operator=(const ValueMap&) LLVM_DELETED_FUNCTION;
84public:
85  typedef KeyT key_type;
86  typedef ValueT mapped_type;
87  typedef std::pair<KeyT, ValueT> value_type;
88
89  explicit ValueMap(unsigned NumInitBuckets = 64)
90    : Map(NumInitBuckets), Data() {}
91  explicit ValueMap(const ExtraData &Data, unsigned NumInitBuckets = 64)
92    : Map(NumInitBuckets), Data(Data) {}
93
94  ~ValueMap() {}
95
96  typedef ValueMapIterator<MapT, KeyT> iterator;
97  typedef ValueMapConstIterator<MapT, KeyT> const_iterator;
98  inline iterator begin() { return iterator(Map.begin()); }
99  inline iterator end() { return iterator(Map.end()); }
100  inline const_iterator begin() const { return const_iterator(Map.begin()); }
101  inline const_iterator end() const { return const_iterator(Map.end()); }
102
103  bool empty() const { return Map.empty(); }
104  unsigned size() const { return Map.size(); }
105
106  /// Grow the map so that it has at least Size buckets. Does not shrink
107  void resize(size_t Size) { Map.resize(Size); }
108
109  void clear() { Map.clear(); }
110
111  /// count - Return true if the specified key is in the map.
112  bool count(const KeyT &Val) const {
113    return Map.find_as(Val) != Map.end();
114  }
115
116  iterator find(const KeyT &Val) {
117    return iterator(Map.find_as(Val));
118  }
119  const_iterator find(const KeyT &Val) const {
120    return const_iterator(Map.find_as(Val));
121  }
122
123  /// lookup - Return the entry for the specified key, or a default
124  /// constructed value if no such entry exists.
125  ValueT lookup(const KeyT &Val) const {
126    typename MapT::const_iterator I = Map.find_as(Val);
127    return I != Map.end() ? I->second : ValueT();
128  }
129
130  // Inserts key,value pair into the map if the key isn't already in the map.
131  // If the key is already in the map, it returns false and doesn't update the
132  // value.
133  std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
134    std::pair<typename MapT::iterator, bool> map_result=
135      Map.insert(std::make_pair(Wrap(KV.first), KV.second));
136    return std::make_pair(iterator(map_result.first), map_result.second);
137  }
138
139  /// insert - Range insertion of pairs.
140  template<typename InputIt>
141  void insert(InputIt I, InputIt E) {
142    for (; I != E; ++I)
143      insert(*I);
144  }
145
146
147  bool erase(const KeyT &Val) {
148    typename MapT::iterator I = Map.find_as(Val);
149    if (I == Map.end())
150      return false;
151
152    Map.erase(I);
153    return true;
154  }
155  void erase(iterator I) {
156    return Map.erase(I.base());
157  }
158
159  value_type& FindAndConstruct(const KeyT &Key) {
160    return Map.FindAndConstruct(Wrap(Key));
161  }
162
163  ValueT &operator[](const KeyT &Key) {
164    return Map[Wrap(Key)];
165  }
166
167  /// isPointerIntoBucketsArray - Return true if the specified pointer points
168  /// somewhere into the ValueMap's array of buckets (i.e. either to a key or
169  /// value in the ValueMap).
170  bool isPointerIntoBucketsArray(const void *Ptr) const {
171    return Map.isPointerIntoBucketsArray(Ptr);
172  }
173
174  /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
175  /// array.  In conjunction with the previous method, this can be used to
176  /// determine whether an insertion caused the ValueMap to reallocate.
177  const void *getPointerIntoBucketsArray() const {
178    return Map.getPointerIntoBucketsArray();
179  }
180
181private:
182  // Takes a key being looked up in the map and wraps it into a
183  // ValueMapCallbackVH, the actual key type of the map.  We use a helper
184  // function because ValueMapCVH is constructed with a second parameter.
185  ValueMapCVH Wrap(KeyT key) const {
186    // The only way the resulting CallbackVH could try to modify *this (making
187    // the const_cast incorrect) is if it gets inserted into the map.  But then
188    // this function must have been called from a non-const method, making the
189    // const_cast ok.
190    return ValueMapCVH(key, const_cast<ValueMap*>(this));
191  }
192};
193
194// This CallbackVH updates its ValueMap when the contained Value changes,
195// according to the user's preferences expressed through the Config object.
196template<typename KeyT, typename ValueT, typename Config>
197class ValueMapCallbackVH : public CallbackVH {
198  friend class ValueMap<KeyT, ValueT, Config>;
199  friend struct DenseMapInfo<ValueMapCallbackVH>;
200  typedef ValueMap<KeyT, ValueT, Config> ValueMapT;
201  typedef typename llvm::remove_pointer<KeyT>::type KeySansPointerT;
202
203  ValueMapT *Map;
204
205  ValueMapCallbackVH(KeyT Key, ValueMapT *Map)
206      : CallbackVH(const_cast<Value*>(static_cast<const Value*>(Key))),
207        Map(Map) {}
208
209public:
210  KeyT Unwrap() const { return cast_or_null<KeySansPointerT>(getValPtr()); }
211
212  virtual void deleted() {
213    // Make a copy that won't get changed even when *this is destroyed.
214    ValueMapCallbackVH Copy(*this);
215    sys::Mutex *M = Config::getMutex(Copy.Map->Data);
216    if (M)
217      M->acquire();
218    Config::onDelete(Copy.Map->Data, Copy.Unwrap());  // May destroy *this.
219    Copy.Map->Map.erase(Copy);  // Definitely destroys *this.
220    if (M)
221      M->release();
222  }
223  virtual void allUsesReplacedWith(Value *new_key) {
224    assert(isa<KeySansPointerT>(new_key) &&
225           "Invalid RAUW on key of ValueMap<>");
226    // Make a copy that won't get changed even when *this is destroyed.
227    ValueMapCallbackVH Copy(*this);
228    sys::Mutex *M = Config::getMutex(Copy.Map->Data);
229    if (M)
230      M->acquire();
231
232    KeyT typed_new_key = cast<KeySansPointerT>(new_key);
233    // Can destroy *this:
234    Config::onRAUW(Copy.Map->Data, Copy.Unwrap(), typed_new_key);
235    if (Config::FollowRAUW) {
236      typename ValueMapT::MapT::iterator I = Copy.Map->Map.find(Copy);
237      // I could == Copy.Map->Map.end() if the onRAUW callback already
238      // removed the old mapping.
239      if (I != Copy.Map->Map.end()) {
240        ValueT Target(I->second);
241        Copy.Map->Map.erase(I);  // Definitely destroys *this.
242        Copy.Map->insert(std::make_pair(typed_new_key, Target));
243      }
244    }
245    if (M)
246      M->release();
247  }
248};
249
250template<typename KeyT, typename ValueT, typename Config>
251struct DenseMapInfo<ValueMapCallbackVH<KeyT, ValueT, Config> > {
252  typedef ValueMapCallbackVH<KeyT, ValueT, Config> VH;
253  typedef DenseMapInfo<KeyT> PointerInfo;
254
255  static inline VH getEmptyKey() {
256    return VH(PointerInfo::getEmptyKey(), NULL);
257  }
258  static inline VH getTombstoneKey() {
259    return VH(PointerInfo::getTombstoneKey(), NULL);
260  }
261  static unsigned getHashValue(const VH &Val) {
262    return PointerInfo::getHashValue(Val.Unwrap());
263  }
264  static unsigned getHashValue(const KeyT &Val) {
265    return PointerInfo::getHashValue(Val);
266  }
267  static bool isEqual(const VH &LHS, const VH &RHS) {
268    return LHS == RHS;
269  }
270  static bool isEqual(const KeyT &LHS, const VH &RHS) {
271    return LHS == RHS.getValPtr();
272  }
273};
274
275
276template<typename DenseMapT, typename KeyT>
277class ValueMapIterator :
278    public std::iterator<std::forward_iterator_tag,
279                         std::pair<KeyT, typename DenseMapT::mapped_type>,
280                         ptrdiff_t> {
281  typedef typename DenseMapT::iterator BaseT;
282  typedef typename DenseMapT::mapped_type ValueT;
283  BaseT I;
284public:
285  ValueMapIterator() : I() {}
286
287  ValueMapIterator(BaseT I) : I(I) {}
288
289  BaseT base() const { return I; }
290
291  struct ValueTypeProxy {
292    const KeyT first;
293    ValueT& second;
294    ValueTypeProxy *operator->() { return this; }
295    operator std::pair<KeyT, ValueT>() const {
296      return std::make_pair(first, second);
297    }
298  };
299
300  ValueTypeProxy operator*() const {
301    ValueTypeProxy Result = {I->first.Unwrap(), I->second};
302    return Result;
303  }
304
305  ValueTypeProxy operator->() const {
306    return operator*();
307  }
308
309  bool operator==(const ValueMapIterator &RHS) const {
310    return I == RHS.I;
311  }
312  bool operator!=(const ValueMapIterator &RHS) const {
313    return I != RHS.I;
314  }
315
316  inline ValueMapIterator& operator++() {  // Preincrement
317    ++I;
318    return *this;
319  }
320  ValueMapIterator operator++(int) {  // Postincrement
321    ValueMapIterator tmp = *this; ++*this; return tmp;
322  }
323};
324
325template<typename DenseMapT, typename KeyT>
326class ValueMapConstIterator :
327    public std::iterator<std::forward_iterator_tag,
328                         std::pair<KeyT, typename DenseMapT::mapped_type>,
329                         ptrdiff_t> {
330  typedef typename DenseMapT::const_iterator BaseT;
331  typedef typename DenseMapT::mapped_type ValueT;
332  BaseT I;
333public:
334  ValueMapConstIterator() : I() {}
335  ValueMapConstIterator(BaseT I) : I(I) {}
336  ValueMapConstIterator(ValueMapIterator<DenseMapT, KeyT> Other)
337    : I(Other.base()) {}
338
339  BaseT base() const { return I; }
340
341  struct ValueTypeProxy {
342    const KeyT first;
343    const ValueT& second;
344    ValueTypeProxy *operator->() { return this; }
345    operator std::pair<KeyT, ValueT>() const {
346      return std::make_pair(first, second);
347    }
348  };
349
350  ValueTypeProxy operator*() const {
351    ValueTypeProxy Result = {I->first.Unwrap(), I->second};
352    return Result;
353  }
354
355  ValueTypeProxy operator->() const {
356    return operator*();
357  }
358
359  bool operator==(const ValueMapConstIterator &RHS) const {
360    return I == RHS.I;
361  }
362  bool operator!=(const ValueMapConstIterator &RHS) const {
363    return I != RHS.I;
364  }
365
366  inline ValueMapConstIterator& operator++() {  // Preincrement
367    ++I;
368    return *this;
369  }
370  ValueMapConstIterator operator++(int) {  // Postincrement
371    ValueMapConstIterator tmp = *this; ++*this; return tmp;
372  }
373};
374
375} // end namespace llvm
376
377#endif
378