1 //===- ValueMap.h - Safe map from Values to data ----------------*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
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.
24 //===----------------------------------------------------------------------===//
26 #ifndef LLVM_IR_VALUEMAP_H
27 #define LLVM_IR_VALUEMAP_H
29 #include "llvm/ADT/DenseMap.h"
30 #include "llvm/IR/TrackingMDRef.h"
31 #include "llvm/IR/ValueHandle.h"
32 #include "llvm/Support/Mutex.h"
33 #include "llvm/Support/UniqueLock.h"
34 #include "llvm/Support/type_traits.h"
40 template<typename KeyT, typename ValueT, typename Config>
41 class ValueMapCallbackVH;
43 template<typename DenseMapT, typename KeyT>
44 class ValueMapIterator;
45 template<typename DenseMapT, typename KeyT>
46 class ValueMapConstIterator;
48 /// This class defines the default behavior for configurable aspects of
49 /// ValueMap<>. User Configs should inherit from this class to be as compatible
50 /// as possible with future versions of ValueMap.
51 template<typename KeyT, typename MutexT = sys::Mutex>
52 struct ValueMapConfig {
53 typedef MutexT mutex_type;
55 /// If FollowRAUW is true, the ValueMap will update mappings on RAUW. If it's
56 /// false, the ValueMap will leave the original mapping in place.
57 enum { FollowRAUW = true };
59 // All methods will be called with a first argument of type ExtraData. The
60 // default implementations in this class take a templated first argument so
61 // that users' subclasses can use any type they want without having to
62 // override all the defaults.
65 template<typename ExtraDataT>
66 static void onRAUW(const ExtraDataT & /*Data*/, KeyT /*Old*/, KeyT /*New*/) {}
67 template<typename ExtraDataT>
68 static void onDelete(const ExtraDataT &/*Data*/, KeyT /*Old*/) {}
70 /// Returns a mutex that should be acquired around any changes to the map.
71 /// This is only acquired from the CallbackVH (and held around calls to onRAUW
72 /// and onDelete) and not inside other ValueMap methods. NULL means that no
73 /// mutex is necessary.
74 template<typename ExtraDataT>
75 static mutex_type *getMutex(const ExtraDataT &/*Data*/) { return nullptr; }
78 /// See the file comment.
79 template<typename KeyT, typename ValueT, typename Config =ValueMapConfig<KeyT> >
81 friend class ValueMapCallbackVH<KeyT, ValueT, Config>;
82 typedef ValueMapCallbackVH<KeyT, ValueT, Config> ValueMapCVH;
83 typedef DenseMap<ValueMapCVH, ValueT, DenseMapInfo<ValueMapCVH> > MapT;
84 typedef DenseMap<const Metadata *, TrackingMDRef> MDMapT;
85 typedef typename Config::ExtraData ExtraData;
87 std::unique_ptr<MDMapT> MDMap;
89 ValueMap(const ValueMap&) = delete;
90 ValueMap& operator=(const ValueMap&) = delete;
92 typedef KeyT key_type;
93 typedef ValueT mapped_type;
94 typedef std::pair<KeyT, ValueT> value_type;
95 typedef unsigned size_type;
97 explicit ValueMap(unsigned NumInitBuckets = 64)
98 : Map(NumInitBuckets), Data() {}
99 explicit ValueMap(const ExtraData &Data, unsigned NumInitBuckets = 64)
100 : Map(NumInitBuckets), Data(Data) {}
102 bool hasMD() const { return MDMap; }
105 MDMap.reset(new MDMapT);
109 typedef ValueMapIterator<MapT, KeyT> iterator;
110 typedef ValueMapConstIterator<MapT, KeyT> const_iterator;
111 inline iterator begin() { return iterator(Map.begin()); }
112 inline iterator end() { return iterator(Map.end()); }
113 inline const_iterator begin() const { return const_iterator(Map.begin()); }
114 inline const_iterator end() const { return const_iterator(Map.end()); }
116 bool empty() const { return Map.empty(); }
117 size_type size() const { return Map.size(); }
119 /// Grow the map so that it has at least Size buckets. Does not shrink
120 void resize(size_t Size) { Map.resize(Size); }
127 /// Return 1 if the specified key is in the map, 0 otherwise.
128 size_type count(const KeyT &Val) const {
129 return Map.find_as(Val) == Map.end() ? 0 : 1;
132 iterator find(const KeyT &Val) {
133 return iterator(Map.find_as(Val));
135 const_iterator find(const KeyT &Val) const {
136 return const_iterator(Map.find_as(Val));
139 /// lookup - Return the entry for the specified key, or a default
140 /// constructed value if no such entry exists.
141 ValueT lookup(const KeyT &Val) const {
142 typename MapT::const_iterator I = Map.find_as(Val);
143 return I != Map.end() ? I->second : ValueT();
146 // Inserts key,value pair into the map if the key isn't already in the map.
147 // If the key is already in the map, it returns false and doesn't update the
149 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
150 std::pair<typename MapT::iterator, bool> map_result=
151 Map.insert(std::make_pair(Wrap(KV.first), KV.second));
152 return std::make_pair(iterator(map_result.first), map_result.second);
155 /// insert - Range insertion of pairs.
156 template<typename InputIt>
157 void insert(InputIt I, InputIt E) {
163 bool erase(const KeyT &Val) {
164 typename MapT::iterator I = Map.find_as(Val);
171 void erase(iterator I) {
172 return Map.erase(I.base());
175 value_type& FindAndConstruct(const KeyT &Key) {
176 return Map.FindAndConstruct(Wrap(Key));
179 ValueT &operator[](const KeyT &Key) {
180 return Map[Wrap(Key)];
183 /// isPointerIntoBucketsArray - Return true if the specified pointer points
184 /// somewhere into the ValueMap's array of buckets (i.e. either to a key or
185 /// value in the ValueMap).
186 bool isPointerIntoBucketsArray(const void *Ptr) const {
187 return Map.isPointerIntoBucketsArray(Ptr);
190 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
191 /// array. In conjunction with the previous method, this can be used to
192 /// determine whether an insertion caused the ValueMap to reallocate.
193 const void *getPointerIntoBucketsArray() const {
194 return Map.getPointerIntoBucketsArray();
198 // Takes a key being looked up in the map and wraps it into a
199 // ValueMapCallbackVH, the actual key type of the map. We use a helper
200 // function because ValueMapCVH is constructed with a second parameter.
201 ValueMapCVH Wrap(KeyT key) const {
202 // The only way the resulting CallbackVH could try to modify *this (making
203 // the const_cast incorrect) is if it gets inserted into the map. But then
204 // this function must have been called from a non-const method, making the
206 return ValueMapCVH(key, const_cast<ValueMap*>(this));
210 // This CallbackVH updates its ValueMap when the contained Value changes,
211 // according to the user's preferences expressed through the Config object.
212 template<typename KeyT, typename ValueT, typename Config>
213 class ValueMapCallbackVH : public CallbackVH {
214 friend class ValueMap<KeyT, ValueT, Config>;
215 friend struct DenseMapInfo<ValueMapCallbackVH>;
216 typedef ValueMap<KeyT, ValueT, Config> ValueMapT;
217 typedef typename std::remove_pointer<KeyT>::type KeySansPointerT;
221 ValueMapCallbackVH(KeyT Key, ValueMapT *Map)
222 : CallbackVH(const_cast<Value*>(static_cast<const Value*>(Key))),
225 // Private constructor used to create empty/tombstone DenseMap keys.
226 ValueMapCallbackVH(Value *V) : CallbackVH(V), Map(nullptr) {}
229 KeyT Unwrap() const { return cast_or_null<KeySansPointerT>(getValPtr()); }
231 void deleted() override {
232 // Make a copy that won't get changed even when *this is destroyed.
233 ValueMapCallbackVH Copy(*this);
234 typename Config::mutex_type *M = Config::getMutex(Copy.Map->Data);
235 unique_lock<typename Config::mutex_type> Guard;
237 Guard = unique_lock<typename Config::mutex_type>(*M);
238 Config::onDelete(Copy.Map->Data, Copy.Unwrap()); // May destroy *this.
239 Copy.Map->Map.erase(Copy); // Definitely destroys *this.
241 void allUsesReplacedWith(Value *new_key) override {
242 assert(isa<KeySansPointerT>(new_key) &&
243 "Invalid RAUW on key of ValueMap<>");
244 // Make a copy that won't get changed even when *this is destroyed.
245 ValueMapCallbackVH Copy(*this);
246 typename Config::mutex_type *M = Config::getMutex(Copy.Map->Data);
247 unique_lock<typename Config::mutex_type> Guard;
249 Guard = unique_lock<typename Config::mutex_type>(*M);
251 KeyT typed_new_key = cast<KeySansPointerT>(new_key);
252 // Can destroy *this:
253 Config::onRAUW(Copy.Map->Data, Copy.Unwrap(), typed_new_key);
254 if (Config::FollowRAUW) {
255 typename ValueMapT::MapT::iterator I = Copy.Map->Map.find(Copy);
256 // I could == Copy.Map->Map.end() if the onRAUW callback already
257 // removed the old mapping.
258 if (I != Copy.Map->Map.end()) {
259 ValueT Target(I->second);
260 Copy.Map->Map.erase(I); // Definitely destroys *this.
261 Copy.Map->insert(std::make_pair(typed_new_key, Target));
267 template<typename KeyT, typename ValueT, typename Config>
268 struct DenseMapInfo<ValueMapCallbackVH<KeyT, ValueT, Config> > {
269 typedef ValueMapCallbackVH<KeyT, ValueT, Config> VH;
271 static inline VH getEmptyKey() {
272 return VH(DenseMapInfo<Value *>::getEmptyKey());
274 static inline VH getTombstoneKey() {
275 return VH(DenseMapInfo<Value *>::getTombstoneKey());
277 static unsigned getHashValue(const VH &Val) {
278 return DenseMapInfo<KeyT>::getHashValue(Val.Unwrap());
280 static unsigned getHashValue(const KeyT &Val) {
281 return DenseMapInfo<KeyT>::getHashValue(Val);
283 static bool isEqual(const VH &LHS, const VH &RHS) {
286 static bool isEqual(const KeyT &LHS, const VH &RHS) {
287 return LHS == RHS.getValPtr();
292 template<typename DenseMapT, typename KeyT>
293 class ValueMapIterator :
294 public std::iterator<std::forward_iterator_tag,
295 std::pair<KeyT, typename DenseMapT::mapped_type>,
297 typedef typename DenseMapT::iterator BaseT;
298 typedef typename DenseMapT::mapped_type ValueT;
301 ValueMapIterator() : I() {}
303 ValueMapIterator(BaseT I) : I(I) {}
305 BaseT base() const { return I; }
307 struct ValueTypeProxy {
310 ValueTypeProxy *operator->() { return this; }
311 operator std::pair<KeyT, ValueT>() const {
312 return std::make_pair(first, second);
316 ValueTypeProxy operator*() const {
317 ValueTypeProxy Result = {I->first.Unwrap(), I->second};
321 ValueTypeProxy operator->() const {
325 bool operator==(const ValueMapIterator &RHS) const {
328 bool operator!=(const ValueMapIterator &RHS) const {
332 inline ValueMapIterator& operator++() { // Preincrement
336 ValueMapIterator operator++(int) { // Postincrement
337 ValueMapIterator tmp = *this; ++*this; return tmp;
341 template<typename DenseMapT, typename KeyT>
342 class ValueMapConstIterator :
343 public std::iterator<std::forward_iterator_tag,
344 std::pair<KeyT, typename DenseMapT::mapped_type>,
346 typedef typename DenseMapT::const_iterator BaseT;
347 typedef typename DenseMapT::mapped_type ValueT;
350 ValueMapConstIterator() : I() {}
351 ValueMapConstIterator(BaseT I) : I(I) {}
352 ValueMapConstIterator(ValueMapIterator<DenseMapT, KeyT> Other)
355 BaseT base() const { return I; }
357 struct ValueTypeProxy {
359 const ValueT& second;
360 ValueTypeProxy *operator->() { return this; }
361 operator std::pair<KeyT, ValueT>() const {
362 return std::make_pair(first, second);
366 ValueTypeProxy operator*() const {
367 ValueTypeProxy Result = {I->first.Unwrap(), I->second};
371 ValueTypeProxy operator->() const {
375 bool operator==(const ValueMapConstIterator &RHS) const {
378 bool operator!=(const ValueMapConstIterator &RHS) const {
382 inline ValueMapConstIterator& operator++() { // Preincrement
386 ValueMapConstIterator operator++(int) { // Postincrement
387 ValueMapConstIterator tmp = *this; ++*this; return tmp;
391 } // end namespace llvm