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/ValueHandle.h"
31#include "llvm/Support/type_traits.h"
32#include "llvm/Support/Mutex.h"
33
34#include <iterator>
35
36namespace llvm {
37
38template<typename KeyT, typename ValueT, typename Config>
39class ValueMapCallbackVH;
40
41template<typename DenseMapT, typename KeyT>
42class ValueMapIterator;
43template<typename DenseMapT, typename KeyT>
44class ValueMapConstIterator;
45
46/// This class defines the default behavior for configurable aspects of
47/// ValueMap<>.  User Configs should inherit from this class to be as compatible
48/// as possible with future versions of ValueMap.
49template<typename KeyT>
50struct ValueMapConfig {
51  /// If FollowRAUW is true, the ValueMap will update mappings on RAUW. If it's
52  /// false, the ValueMap will leave the original mapping in place.
53  enum { FollowRAUW = true };
54
55  // All methods will be called with a first argument of type ExtraData.  The
56  // default implementations in this class take a templated first argument so
57  // that users' subclasses can use any type they want without having to
58  // override all the defaults.
59  struct ExtraData {};
60
61  template<typename ExtraDataT>
62  static void onRAUW(const ExtraDataT & /*Data*/, KeyT /*Old*/, KeyT /*New*/) {}
63  template<typename ExtraDataT>
64  static void onDelete(const ExtraDataT &/*Data*/, KeyT /*Old*/) {}
65
66  /// Returns a mutex that should be acquired around any changes to the map.
67  /// This is only acquired from the CallbackVH (and held around calls to onRAUW
68  /// and onDelete) and not inside other ValueMap methods.  NULL means that no
69  /// mutex is necessary.
70  template<typename ExtraDataT>
71  static sys::Mutex *getMutex(const ExtraDataT &/*Data*/) { return NULL; }
72};
73
74/// See the file comment.
75template<typename KeyT, typename ValueT, typename Config =ValueMapConfig<KeyT> >
76class ValueMap {
77  friend class ValueMapCallbackVH<KeyT, ValueT, Config>;
78  typedef ValueMapCallbackVH<KeyT, ValueT, Config> ValueMapCVH;
79  typedef DenseMap<ValueMapCVH, ValueT, DenseMapInfo<ValueMapCVH> > MapT;
80  typedef typename Config::ExtraData ExtraData;
81  MapT Map;
82  ExtraData Data;
83  ValueMap(const ValueMap&); // DO NOT IMPLEMENT
84  ValueMap& operator=(const ValueMap&); // DO NOT IMPLEMENT
85public:
86  typedef KeyT key_type;
87  typedef ValueT mapped_type;
88  typedef std::pair<KeyT, ValueT> value_type;
89
90  explicit ValueMap(unsigned NumInitBuckets = 64)
91    : Map(NumInitBuckets), Data() {}
92  explicit ValueMap(const ExtraData &Data, unsigned NumInitBuckets = 64)
93    : Map(NumInitBuckets), Data(Data) {}
94
95  ~ValueMap() {}
96
97  typedef ValueMapIterator<MapT, KeyT> iterator;
98  typedef ValueMapConstIterator<MapT, KeyT> const_iterator;
99  inline iterator begin() { return iterator(Map.begin()); }
100  inline iterator end() { return iterator(Map.end()); }
101  inline const_iterator begin() const { return const_iterator(Map.begin()); }
102  inline const_iterator end() const { return const_iterator(Map.end()); }
103
104  bool empty() const { return Map.empty(); }
105  unsigned size() const { return Map.size(); }
106
107  /// Grow the map so that it has at least Size buckets. Does not shrink
108  void resize(size_t Size) { Map.resize(Size); }
109
110  void clear() { Map.clear(); }
111
112  /// count - Return true if the specified key is in the map.
113  bool count(const KeyT &Val) const {
114    return Map.find_as(Val) != Map.end();
115  }
116
117  iterator find(const KeyT &Val) {
118    return iterator(Map.find_as(Val));
119  }
120  const_iterator find(const KeyT &Val) const {
121    return const_iterator(Map.find_as(Val));
122  }
123
124  /// lookup - Return the entry for the specified key, or a default
125  /// constructed value if no such entry exists.
126  ValueT lookup(const KeyT &Val) const {
127    typename MapT::const_iterator I = Map.find_as(Val);
128    return I != Map.end() ? I->second : ValueT();
129  }
130
131  // Inserts key,value pair into the map if the key isn't already in the map.
132  // If the key is already in the map, it returns false and doesn't update the
133  // value.
134  std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
135    std::pair<typename MapT::iterator, bool> map_result=
136      Map.insert(std::make_pair(Wrap(KV.first), KV.second));
137    return std::make_pair(iterator(map_result.first), map_result.second);
138  }
139
140  /// insert - Range insertion of pairs.
141  template<typename InputIt>
142  void insert(InputIt I, InputIt E) {
143    for (; I != E; ++I)
144      insert(*I);
145  }
146
147
148  bool erase(const KeyT &Val) {
149    typename MapT::iterator I = Map.find_as(Val);
150    if (I == Map.end())
151      return false;
152
153    Map.erase(I);
154    return true;
155  }
156  void erase(iterator I) {
157    return Map.erase(I.base());
158  }
159
160  value_type& FindAndConstruct(const KeyT &Key) {
161    return Map.FindAndConstruct(Wrap(Key));
162  }
163
164  ValueT &operator[](const KeyT &Key) {
165    return Map[Wrap(Key)];
166  }
167
168  /// isPointerIntoBucketsArray - Return true if the specified pointer points
169  /// somewhere into the ValueMap's array of buckets (i.e. either to a key or
170  /// value in the ValueMap).
171  bool isPointerIntoBucketsArray(const void *Ptr) const {
172    return Map.isPointerIntoBucketsArray(Ptr);
173  }
174
175  /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
176  /// array.  In conjunction with the previous method, this can be used to
177  /// determine whether an insertion caused the ValueMap to reallocate.
178  const void *getPointerIntoBucketsArray() const {
179    return Map.getPointerIntoBucketsArray();
180  }
181
182private:
183  // Takes a key being looked up in the map and wraps it into a
184  // ValueMapCallbackVH, the actual key type of the map.  We use a helper
185  // function because ValueMapCVH is constructed with a second parameter.
186  ValueMapCVH Wrap(KeyT key) const {
187    // The only way the resulting CallbackVH could try to modify *this (making
188    // the const_cast incorrect) is if it gets inserted into the map.  But then
189    // this function must have been called from a non-const method, making the
190    // const_cast ok.
191    return ValueMapCVH(key, const_cast<ValueMap*>(this));
192  }
193};
194
195// This CallbackVH updates its ValueMap when the contained Value changes,
196// according to the user's preferences expressed through the Config object.
197template<typename KeyT, typename ValueT, typename Config>
198class ValueMapCallbackVH : public CallbackVH {
199  friend class ValueMap<KeyT, ValueT, Config>;
200  friend struct DenseMapInfo<ValueMapCallbackVH>;
201  typedef ValueMap<KeyT, ValueT, Config> ValueMapT;
202  typedef typename llvm::remove_pointer<KeyT>::type KeySansPointerT;
203
204  ValueMapT *Map;
205
206  ValueMapCallbackVH(KeyT Key, ValueMapT *Map)
207      : CallbackVH(const_cast<Value*>(static_cast<const Value*>(Key))),
208        Map(Map) {}
209
210public:
211  KeyT Unwrap() const { return cast_or_null<KeySansPointerT>(getValPtr()); }
212
213  virtual void deleted() {
214    // Make a copy that won't get changed even when *this is destroyed.
215    ValueMapCallbackVH Copy(*this);
216    sys::Mutex *M = Config::getMutex(Copy.Map->Data);
217    if (M)
218      M->acquire();
219    Config::onDelete(Copy.Map->Data, Copy.Unwrap());  // May destroy *this.
220    Copy.Map->Map.erase(Copy);  // Definitely destroys *this.
221    if (M)
222      M->release();
223  }
224  virtual void allUsesReplacedWith(Value *new_key) {
225    assert(isa<KeySansPointerT>(new_key) &&
226           "Invalid RAUW on key of ValueMap<>");
227    // Make a copy that won't get changed even when *this is destroyed.
228    ValueMapCallbackVH Copy(*this);
229    sys::Mutex *M = Config::getMutex(Copy.Map->Data);
230    if (M)
231      M->acquire();
232
233    KeyT typed_new_key = cast<KeySansPointerT>(new_key);
234    // Can destroy *this:
235    Config::onRAUW(Copy.Map->Data, Copy.Unwrap(), typed_new_key);
236    if (Config::FollowRAUW) {
237      typename ValueMapT::MapT::iterator I = Copy.Map->Map.find(Copy);
238      // I could == Copy.Map->Map.end() if the onRAUW callback already
239      // removed the old mapping.
240      if (I != Copy.Map->Map.end()) {
241        ValueT Target(I->second);
242        Copy.Map->Map.erase(I);  // Definitely destroys *this.
243        Copy.Map->insert(std::make_pair(typed_new_key, Target));
244      }
245    }
246    if (M)
247      M->release();
248  }
249};
250
251template<typename KeyT, typename ValueT, typename Config>
252struct DenseMapInfo<ValueMapCallbackVH<KeyT, ValueT, Config> > {
253  typedef ValueMapCallbackVH<KeyT, ValueT, Config> VH;
254  typedef DenseMapInfo<KeyT> PointerInfo;
255
256  static inline VH getEmptyKey() {
257    return VH(PointerInfo::getEmptyKey(), NULL);
258  }
259  static inline VH getTombstoneKey() {
260    return VH(PointerInfo::getTombstoneKey(), NULL);
261  }
262  static unsigned getHashValue(const VH &Val) {
263    return PointerInfo::getHashValue(Val.Unwrap());
264  }
265  static unsigned getHashValue(const KeyT &Val) {
266    return PointerInfo::getHashValue(Val);
267  }
268  static bool isEqual(const VH &LHS, const VH &RHS) {
269    return LHS == RHS;
270  }
271  static bool isEqual(const KeyT &LHS, const VH &RHS) {
272    return LHS == RHS.getValPtr();
273  }
274};
275
276
277template<typename DenseMapT, typename KeyT>
278class ValueMapIterator :
279    public std::iterator<std::forward_iterator_tag,
280                         std::pair<KeyT, typename DenseMapT::mapped_type>,
281                         ptrdiff_t> {
282  typedef typename DenseMapT::iterator BaseT;
283  typedef typename DenseMapT::mapped_type ValueT;
284  BaseT I;
285public:
286  ValueMapIterator() : I() {}
287
288  ValueMapIterator(BaseT I) : I(I) {}
289
290  BaseT base() const { return I; }
291
292  struct ValueTypeProxy {
293    const KeyT first;
294    ValueT& second;
295    ValueTypeProxy *operator->() { return this; }
296    operator std::pair<KeyT, ValueT>() const {
297      return std::make_pair(first, second);
298    }
299  };
300
301  ValueTypeProxy operator*() const {
302    ValueTypeProxy Result = {I->first.Unwrap(), I->second};
303    return Result;
304  }
305
306  ValueTypeProxy operator->() const {
307    return operator*();
308  }
309
310  bool operator==(const ValueMapIterator &RHS) const {
311    return I == RHS.I;
312  }
313  bool operator!=(const ValueMapIterator &RHS) const {
314    return I != RHS.I;
315  }
316
317  inline ValueMapIterator& operator++() {  // Preincrement
318    ++I;
319    return *this;
320  }
321  ValueMapIterator operator++(int) {  // Postincrement
322    ValueMapIterator tmp = *this; ++*this; return tmp;
323  }
324};
325
326template<typename DenseMapT, typename KeyT>
327class ValueMapConstIterator :
328    public std::iterator<std::forward_iterator_tag,
329                         std::pair<KeyT, typename DenseMapT::mapped_type>,
330                         ptrdiff_t> {
331  typedef typename DenseMapT::const_iterator BaseT;
332  typedef typename DenseMapT::mapped_type ValueT;
333  BaseT I;
334public:
335  ValueMapConstIterator() : I() {}
336  ValueMapConstIterator(BaseT I) : I(I) {}
337  ValueMapConstIterator(ValueMapIterator<DenseMapT, KeyT> Other)
338    : I(Other.base()) {}
339
340  BaseT base() const { return I; }
341
342  struct ValueTypeProxy {
343    const KeyT first;
344    const ValueT& second;
345    ValueTypeProxy *operator->() { return this; }
346    operator std::pair<KeyT, ValueT>() const {
347      return std::make_pair(first, second);
348    }
349  };
350
351  ValueTypeProxy operator*() const {
352    ValueTypeProxy Result = {I->first.Unwrap(), I->second};
353    return Result;
354  }
355
356  ValueTypeProxy operator->() const {
357    return operator*();
358  }
359
360  bool operator==(const ValueMapConstIterator &RHS) const {
361    return I == RHS.I;
362  }
363  bool operator!=(const ValueMapConstIterator &RHS) const {
364    return I != RHS.I;
365  }
366
367  inline ValueMapConstIterator& operator++() {  // Preincrement
368    ++I;
369    return *this;
370  }
371  ValueMapConstIterator operator++(int) {  // Postincrement
372    ValueMapConstIterator tmp = *this; ++*this; return tmp;
373  }
374};
375
376} // end namespace llvm
377
378#endif
379