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/ValueHandle.h"
31 #include "llvm/Support/Mutex.h"
32 #include "llvm/Support/UniqueLock.h"
33 #include "llvm/Support/type_traits.h"
38 template<typename KeyT, typename ValueT, typename Config>
39 class ValueMapCallbackVH;
41 template<typename DenseMapT, typename KeyT>
42 class ValueMapIterator;
43 template<typename DenseMapT, typename KeyT>
44 class ValueMapConstIterator;
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.
49 template<typename KeyT, typename MutexT = sys::Mutex>
50 struct ValueMapConfig {
51 typedef MutexT mutex_type;
53 /// If FollowRAUW is true, the ValueMap will update mappings on RAUW. If it's
54 /// false, the ValueMap will leave the original mapping in place.
55 enum { FollowRAUW = true };
57 // All methods will be called with a first argument of type ExtraData. The
58 // default implementations in this class take a templated first argument so
59 // that users' subclasses can use any type they want without having to
60 // override all the defaults.
63 template<typename ExtraDataT>
64 static void onRAUW(const ExtraDataT & /*Data*/, KeyT /*Old*/, KeyT /*New*/) {}
65 template<typename ExtraDataT>
66 static void onDelete(const ExtraDataT &/*Data*/, KeyT /*Old*/) {}
68 /// Returns a mutex that should be acquired around any changes to the map.
69 /// This is only acquired from the CallbackVH (and held around calls to onRAUW
70 /// and onDelete) and not inside other ValueMap methods. NULL means that no
71 /// mutex is necessary.
72 template<typename ExtraDataT>
73 static mutex_type *getMutex(const ExtraDataT &/*Data*/) { return nullptr; }
76 /// See the file comment.
77 template<typename KeyT, typename ValueT, typename Config =ValueMapConfig<KeyT> >
79 friend class ValueMapCallbackVH<KeyT, ValueT, Config>;
80 typedef ValueMapCallbackVH<KeyT, ValueT, Config> ValueMapCVH;
81 typedef DenseMap<ValueMapCVH, ValueT, DenseMapInfo<ValueMapCVH> > MapT;
82 typedef typename Config::ExtraData ExtraData;
85 ValueMap(const ValueMap&) LLVM_DELETED_FUNCTION;
86 ValueMap& operator=(const ValueMap&) LLVM_DELETED_FUNCTION;
88 typedef KeyT key_type;
89 typedef ValueT mapped_type;
90 typedef std::pair<KeyT, ValueT> value_type;
91 typedef unsigned size_type;
93 explicit ValueMap(unsigned NumInitBuckets = 64)
94 : Map(NumInitBuckets), Data() {}
95 explicit ValueMap(const ExtraData &Data, unsigned NumInitBuckets = 64)
96 : Map(NumInitBuckets), Data(Data) {}
100 typedef ValueMapIterator<MapT, KeyT> iterator;
101 typedef ValueMapConstIterator<MapT, KeyT> const_iterator;
102 inline iterator begin() { return iterator(Map.begin()); }
103 inline iterator end() { return iterator(Map.end()); }
104 inline const_iterator begin() const { return const_iterator(Map.begin()); }
105 inline const_iterator end() const { return const_iterator(Map.end()); }
107 bool empty() const { return Map.empty(); }
108 size_type size() const { return Map.size(); }
110 /// Grow the map so that it has at least Size buckets. Does not shrink
111 void resize(size_t Size) { Map.resize(Size); }
113 void clear() { Map.clear(); }
115 /// Return 1 if the specified key is in the map, 0 otherwise.
116 size_type count(const KeyT &Val) const {
117 return Map.find_as(Val) == Map.end() ? 0 : 1;
120 iterator find(const KeyT &Val) {
121 return iterator(Map.find_as(Val));
123 const_iterator find(const KeyT &Val) const {
124 return const_iterator(Map.find_as(Val));
127 /// lookup - Return the entry for the specified key, or a default
128 /// constructed value if no such entry exists.
129 ValueT lookup(const KeyT &Val) const {
130 typename MapT::const_iterator I = Map.find_as(Val);
131 return I != Map.end() ? I->second : ValueT();
134 // Inserts key,value pair into the map if the key isn't already in the map.
135 // If the key is already in the map, it returns false and doesn't update the
137 std::pair<iterator, bool> insert(const std::pair<KeyT, ValueT> &KV) {
138 std::pair<typename MapT::iterator, bool> map_result=
139 Map.insert(std::make_pair(Wrap(KV.first), KV.second));
140 return std::make_pair(iterator(map_result.first), map_result.second);
143 /// insert - Range insertion of pairs.
144 template<typename InputIt>
145 void insert(InputIt I, InputIt E) {
151 bool erase(const KeyT &Val) {
152 typename MapT::iterator I = Map.find_as(Val);
159 void erase(iterator I) {
160 return Map.erase(I.base());
163 value_type& FindAndConstruct(const KeyT &Key) {
164 return Map.FindAndConstruct(Wrap(Key));
167 ValueT &operator[](const KeyT &Key) {
168 return Map[Wrap(Key)];
171 /// isPointerIntoBucketsArray - Return true if the specified pointer points
172 /// somewhere into the ValueMap's array of buckets (i.e. either to a key or
173 /// value in the ValueMap).
174 bool isPointerIntoBucketsArray(const void *Ptr) const {
175 return Map.isPointerIntoBucketsArray(Ptr);
178 /// getPointerIntoBucketsArray() - Return an opaque pointer into the buckets
179 /// array. In conjunction with the previous method, this can be used to
180 /// determine whether an insertion caused the ValueMap to reallocate.
181 const void *getPointerIntoBucketsArray() const {
182 return Map.getPointerIntoBucketsArray();
186 // Takes a key being looked up in the map and wraps it into a
187 // ValueMapCallbackVH, the actual key type of the map. We use a helper
188 // function because ValueMapCVH is constructed with a second parameter.
189 ValueMapCVH Wrap(KeyT key) const {
190 // The only way the resulting CallbackVH could try to modify *this (making
191 // the const_cast incorrect) is if it gets inserted into the map. But then
192 // this function must have been called from a non-const method, making the
194 return ValueMapCVH(key, const_cast<ValueMap*>(this));
198 // This CallbackVH updates its ValueMap when the contained Value changes,
199 // according to the user's preferences expressed through the Config object.
200 template<typename KeyT, typename ValueT, typename Config>
201 class ValueMapCallbackVH : public CallbackVH {
202 friend class ValueMap<KeyT, ValueT, Config>;
203 friend struct DenseMapInfo<ValueMapCallbackVH>;
204 typedef ValueMap<KeyT, ValueT, Config> ValueMapT;
205 typedef typename std::remove_pointer<KeyT>::type KeySansPointerT;
209 ValueMapCallbackVH(KeyT Key, ValueMapT *Map)
210 : CallbackVH(const_cast<Value*>(static_cast<const Value*>(Key))),
214 KeyT Unwrap() const { return cast_or_null<KeySansPointerT>(getValPtr()); }
216 void deleted() override {
217 // Make a copy that won't get changed even when *this is destroyed.
218 ValueMapCallbackVH Copy(*this);
219 typename Config::mutex_type *M = Config::getMutex(Copy.Map->Data);
220 unique_lock<typename Config::mutex_type> Guard;
222 Guard = unique_lock<typename Config::mutex_type>(*M);
223 Config::onDelete(Copy.Map->Data, Copy.Unwrap()); // May destroy *this.
224 Copy.Map->Map.erase(Copy); // Definitely destroys *this.
226 void allUsesReplacedWith(Value *new_key) override {
227 assert(isa<KeySansPointerT>(new_key) &&
228 "Invalid RAUW on key of ValueMap<>");
229 // Make a copy that won't get changed even when *this is destroyed.
230 ValueMapCallbackVH Copy(*this);
231 typename Config::mutex_type *M = Config::getMutex(Copy.Map->Data);
232 unique_lock<typename Config::mutex_type> Guard;
234 Guard = unique_lock<typename Config::mutex_type>(*M);
236 KeyT typed_new_key = cast<KeySansPointerT>(new_key);
237 // Can destroy *this:
238 Config::onRAUW(Copy.Map->Data, Copy.Unwrap(), typed_new_key);
239 if (Config::FollowRAUW) {
240 typename ValueMapT::MapT::iterator I = Copy.Map->Map.find(Copy);
241 // I could == Copy.Map->Map.end() if the onRAUW callback already
242 // removed the old mapping.
243 if (I != Copy.Map->Map.end()) {
244 ValueT Target(I->second);
245 Copy.Map->Map.erase(I); // Definitely destroys *this.
246 Copy.Map->insert(std::make_pair(typed_new_key, Target));
252 template<typename KeyT, typename ValueT, typename Config>
253 struct DenseMapInfo<ValueMapCallbackVH<KeyT, ValueT, Config> > {
254 typedef ValueMapCallbackVH<KeyT, ValueT, Config> VH;
255 typedef DenseMapInfo<KeyT> PointerInfo;
257 static inline VH getEmptyKey() {
258 return VH(PointerInfo::getEmptyKey(), nullptr);
260 static inline VH getTombstoneKey() {
261 return VH(PointerInfo::getTombstoneKey(), nullptr);
263 static unsigned getHashValue(const VH &Val) {
264 return PointerInfo::getHashValue(Val.Unwrap());
266 static unsigned getHashValue(const KeyT &Val) {
267 return PointerInfo::getHashValue(Val);
269 static bool isEqual(const VH &LHS, const VH &RHS) {
272 static bool isEqual(const KeyT &LHS, const VH &RHS) {
273 return LHS == RHS.getValPtr();
278 template<typename DenseMapT, typename KeyT>
279 class ValueMapIterator :
280 public std::iterator<std::forward_iterator_tag,
281 std::pair<KeyT, typename DenseMapT::mapped_type>,
283 typedef typename DenseMapT::iterator BaseT;
284 typedef typename DenseMapT::mapped_type ValueT;
287 ValueMapIterator() : I() {}
289 ValueMapIterator(BaseT I) : I(I) {}
291 BaseT base() const { return I; }
293 struct ValueTypeProxy {
296 ValueTypeProxy *operator->() { return this; }
297 operator std::pair<KeyT, ValueT>() const {
298 return std::make_pair(first, second);
302 ValueTypeProxy operator*() const {
303 ValueTypeProxy Result = {I->first.Unwrap(), I->second};
307 ValueTypeProxy operator->() const {
311 bool operator==(const ValueMapIterator &RHS) const {
314 bool operator!=(const ValueMapIterator &RHS) const {
318 inline ValueMapIterator& operator++() { // Preincrement
322 ValueMapIterator operator++(int) { // Postincrement
323 ValueMapIterator tmp = *this; ++*this; return tmp;
327 template<typename DenseMapT, typename KeyT>
328 class ValueMapConstIterator :
329 public std::iterator<std::forward_iterator_tag,
330 std::pair<KeyT, typename DenseMapT::mapped_type>,
332 typedef typename DenseMapT::const_iterator BaseT;
333 typedef typename DenseMapT::mapped_type ValueT;
336 ValueMapConstIterator() : I() {}
337 ValueMapConstIterator(BaseT I) : I(I) {}
338 ValueMapConstIterator(ValueMapIterator<DenseMapT, KeyT> Other)
341 BaseT base() const { return I; }
343 struct ValueTypeProxy {
345 const ValueT& second;
346 ValueTypeProxy *operator->() { return this; }
347 operator std::pair<KeyT, ValueT>() const {
348 return std::make_pair(first, second);
352 ValueTypeProxy operator*() const {
353 ValueTypeProxy Result = {I->first.Unwrap(), I->second};
357 ValueTypeProxy operator->() const {
361 bool operator==(const ValueMapConstIterator &RHS) const {
364 bool operator!=(const ValueMapConstIterator &RHS) const {
368 inline ValueMapConstIterator& operator++() { // Preincrement
372 ValueMapConstIterator operator++(int) { // Postincrement
373 ValueMapConstIterator tmp = *this; ++*this; return tmp;
377 } // end namespace llvm