1 //===-- llvm/ADT/FoldingSet.h - Uniquing Hash Set ---------------*- 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 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.
14 //===----------------------------------------------------------------------===//
16 #ifndef LLVM_ADT_FOLDINGSET_H
17 #define LLVM_ADT_FOLDINGSET_H
19 #include "llvm/Support/DataTypes.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringRef.h"
26 class BumpPtrAllocator;
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.
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.
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.
47 /// class MyNode : public FoldingSetNode {
52 /// MyNode(const char *N, unsigned V) : Name(N), Value(V) {}
54 /// void Profile(FoldingSetNodeID &ID) const {
55 /// ID.AddString(Name);
56 /// ID.AddInteger(Value);
61 /// To define the folding set itself use the FoldingSet template;
64 /// FoldingSet<MyNode> MyFoldingSet;
66 /// Four public methods are available to manipulate the folding set;
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;
71 /// MyNode *M = MyFoldingSet.GetOrInsertNode(N);
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.)
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
81 /// FoldingSetNodeID ID;
82 /// ID.AddString(Name);
83 /// ID.AddInteger(Value);
84 /// void *InsertPoint;
86 /// MyNode *M = MyFoldingSet.FindNodeOrInsertPos(ID, InsertPoint);
88 /// If found then M with be non-NULL, else InsertPoint will point to where it
89 /// should be inserted using InsertNode.
91 /// 3) If you get a NULL result from FindNodeOrInsertPos then you can as a new
92 /// node with FindNodeOrInsertPos;
94 /// InsertNode(N, InsertPoint);
96 /// 4) Finally, if you want to remove a node from the folding set call;
98 /// bool WasRemoved = RemoveNode(N);
100 /// The result indicates whether the node existed in the folding set.
102 class FoldingSetNodeID;
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.
111 class FoldingSetImpl {
113 /// Buckets - Array of bucket chains.
117 /// NumBuckets - Length of the Buckets array. Always a power of 2.
121 /// NumNodes - Number of nodes in the folding set. Growth occurs when NumNodes
122 /// is greater than twice the number of buckets.
126 explicit FoldingSetImpl(unsigned Log2InitSize = 6);
127 virtual ~FoldingSetImpl();
129 //===--------------------------------------------------------------------===//
130 /// Node - This class is used to maintain the singly linked bucket list in
135 // NextInFoldingSetBucket - next link in the bucket list.
136 void *NextInFoldingSetBucket;
140 Node() : NextInFoldingSetBucket(0) {}
143 void *getNextInBucket() const { return NextInFoldingSetBucket; }
144 void SetNextInBucket(void *N) { NextInFoldingSetBucket = N; }
147 /// clear - Remove all nodes from the folding set.
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);
154 /// GetOrInsertNode - If there is an existing simple Node exactly
155 /// equal to the specified node, return it. Otherwise, insert 'N' and return
157 Node *GetOrInsertNode(Node *N);
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
162 Node *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos);
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);
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);
174 assert(Inserted == N && "Node already inserted!");
177 /// size - Returns the number of nodes in the folding set.
178 unsigned size() const { return NumNodes; }
180 /// empty - Returns true if there are no nodes in the folding set.
181 bool empty() const { return NumNodes == 0; }
185 /// GrowHashTable - Double the size of the hash table and rehash everything.
187 void GrowHashTable();
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,
197 FoldingSetNodeID &TempID) const=0;
198 /// NodeEquals - Instantiations of the FoldingSet template implement
199 /// this function to compute a hash value for the given node.
200 virtual unsigned ComputeNodeHash(Node *N,
201 FoldingSetNodeID &TempID) const = 0;
204 //===----------------------------------------------------------------------===//
206 template<typename T> struct FoldingSetTrait;
208 /// DefaultFoldingSetTrait - This class provides default implementations
209 /// for FoldingSetTrait implementations.
211 template<typename T> struct DefaultFoldingSetTrait {
212 static void Profile(const T &X, FoldingSetNodeID &ID) {
215 static void Profile(T &X, FoldingSetNodeID &ID) {
219 // Equals - Test if the profile for X would match ID, using TempID
220 // to compute a temporary ID if necessary. The default implementation
221 // just calls Profile and does a regular comparison. Implementations
222 // can override this to provide more efficient implementations.
223 static inline bool Equals(T &X, const FoldingSetNodeID &ID,
224 FoldingSetNodeID &TempID);
226 // ComputeHash - Compute a hash value for X, using TempID to
227 // compute a temporary ID if necessary. The default implementation
228 // just calls Profile and does a regular hash computation.
229 // Implementations can override this to provide more efficient
231 static inline unsigned ComputeHash(T &X, FoldingSetNodeID &TempID);
234 /// FoldingSetTrait - This trait class is used to define behavior of how
235 /// to "profile" (in the FoldingSet parlance) an object of a given type.
236 /// The default behavior is to invoke a 'Profile' method on an object, but
237 /// through template specialization the behavior can be tailored for specific
238 /// types. Combined with the FoldingSetNodeWrapper class, one can add objects
239 /// to FoldingSets that were not originally designed to have that behavior.
240 template<typename T> struct FoldingSetTrait
241 : public DefaultFoldingSetTrait<T> {};
243 template<typename T, typename Ctx> struct ContextualFoldingSetTrait;
245 /// DefaultContextualFoldingSetTrait - Like DefaultFoldingSetTrait, but
246 /// for ContextualFoldingSets.
247 template<typename T, typename Ctx>
248 struct DefaultContextualFoldingSetTrait {
249 static void Profile(T &X, FoldingSetNodeID &ID, Ctx Context) {
250 X.Profile(ID, Context);
252 static inline bool Equals(T &X, const FoldingSetNodeID &ID,
253 FoldingSetNodeID &TempID, Ctx Context);
254 static inline unsigned ComputeHash(T &X, FoldingSetNodeID &TempID,
258 /// ContextualFoldingSetTrait - Like FoldingSetTrait, but for
259 /// ContextualFoldingSets.
260 template<typename T, typename Ctx> struct ContextualFoldingSetTrait
261 : public DefaultContextualFoldingSetTrait<T, Ctx> {};
263 //===--------------------------------------------------------------------===//
264 /// FoldingSetNodeIDRef - This class describes a reference to an interned
265 /// FoldingSetNodeID, which can be a useful to store node id data rather
266 /// than using plain FoldingSetNodeIDs, since the 32-element SmallVector
267 /// is often much larger than necessary, and the possibility of heap
268 /// allocation means it requires a non-trivial destructor call.
269 class FoldingSetNodeIDRef {
270 const unsigned *Data;
273 FoldingSetNodeIDRef() : Data(0), Size(0) {}
274 FoldingSetNodeIDRef(const unsigned *D, size_t S) : Data(D), Size(S) {}
276 /// ComputeHash - Compute a strong hash value for this FoldingSetNodeIDRef,
277 /// used to lookup the node in the FoldingSetImpl.
278 unsigned ComputeHash() const;
280 bool operator==(FoldingSetNodeIDRef) const;
282 const unsigned *getData() const { return Data; }
283 size_t getSize() const { return Size; }
286 //===--------------------------------------------------------------------===//
287 /// FoldingSetNodeID - This class is used to gather all the unique data bits of
288 /// a node. When all the bits are gathered this class is used to produce a
289 /// hash value for the node.
291 class FoldingSetNodeID {
292 /// Bits - Vector of all the data bits that make the node unique.
293 /// Use a SmallVector to avoid a heap allocation in the common case.
294 SmallVector<unsigned, 32> Bits;
297 FoldingSetNodeID() {}
299 FoldingSetNodeID(FoldingSetNodeIDRef Ref)
300 : Bits(Ref.getData(), Ref.getData() + Ref.getSize()) {}
302 /// Add* - Add various data types to Bit data.
304 void AddPointer(const void *Ptr);
305 void AddInteger(signed I);
306 void AddInteger(unsigned I);
307 void AddInteger(long I);
308 void AddInteger(unsigned long I);
309 void AddInteger(long long I);
310 void AddInteger(unsigned long long I);
311 void AddBoolean(bool B) { AddInteger(B ? 1U : 0U); }
312 void AddString(StringRef String);
313 void AddNodeID(const FoldingSetNodeID &ID);
315 template <typename T>
316 inline void Add(const T &x) { FoldingSetTrait<T>::Profile(x, *this); }
318 /// clear - Clear the accumulated profile, allowing this FoldingSetNodeID
319 /// object to be used to compute a new profile.
320 inline void clear() { Bits.clear(); }
322 /// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used
323 /// to lookup the node in the FoldingSetImpl.
324 unsigned ComputeHash() const;
326 /// operator== - Used to compare two nodes to each other.
328 bool operator==(const FoldingSetNodeID &RHS) const;
329 bool operator==(const FoldingSetNodeIDRef RHS) const;
331 /// Intern - Copy this node's data to a memory region allocated from the
332 /// given allocator and return a FoldingSetNodeIDRef describing the
334 FoldingSetNodeIDRef Intern(BumpPtrAllocator &Allocator) const;
337 // Convenience type to hide the implementation of the folding set.
338 typedef FoldingSetImpl::Node FoldingSetNode;
339 template<class T> class FoldingSetIterator;
340 template<class T> class FoldingSetBucketIterator;
342 // Definitions of FoldingSetTrait and ContextualFoldingSetTrait functions, which
343 // require the definition of FoldingSetNodeID.
346 DefaultFoldingSetTrait<T>::Equals(T &X, const FoldingSetNodeID &ID,
347 FoldingSetNodeID &TempID) {
348 FoldingSetTrait<T>::Profile(X, TempID);
353 DefaultFoldingSetTrait<T>::ComputeHash(T &X, FoldingSetNodeID &TempID) {
354 FoldingSetTrait<T>::Profile(X, TempID);
355 return TempID.ComputeHash();
357 template<typename T, typename Ctx>
359 DefaultContextualFoldingSetTrait<T, Ctx>::Equals(T &X,
360 const FoldingSetNodeID &ID,
361 FoldingSetNodeID &TempID,
363 ContextualFoldingSetTrait<T, Ctx>::Profile(X, TempID, Context);
366 template<typename T, typename Ctx>
368 DefaultContextualFoldingSetTrait<T, Ctx>::ComputeHash(T &X,
369 FoldingSetNodeID &TempID,
371 ContextualFoldingSetTrait<T, Ctx>::Profile(X, TempID, Context);
372 return TempID.ComputeHash();
375 //===----------------------------------------------------------------------===//
376 /// FoldingSet - This template class is used to instantiate a specialized
377 /// implementation of the folding set to the node class T. T must be a
378 /// subclass of FoldingSetNode and implement a Profile function.
380 template<class T> class FoldingSet : public FoldingSetImpl {
382 /// GetNodeProfile - Each instantiatation of the FoldingSet needs to provide a
383 /// way to convert nodes into a unique specifier.
384 virtual void GetNodeProfile(Node *N, FoldingSetNodeID &ID) const {
385 T *TN = static_cast<T *>(N);
386 FoldingSetTrait<T>::Profile(*TN, ID);
388 /// NodeEquals - Instantiations may optionally provide a way to compare a
389 /// node with a specified ID.
390 virtual bool NodeEquals(Node *N, const FoldingSetNodeID &ID,
391 FoldingSetNodeID &TempID) const {
392 T *TN = static_cast<T *>(N);
393 return FoldingSetTrait<T>::Equals(*TN, ID, TempID);
395 /// NodeEquals - Instantiations may optionally provide a way to compute a
396 /// hash value directly from a node.
397 virtual unsigned ComputeNodeHash(Node *N,
398 FoldingSetNodeID &TempID) const {
399 T *TN = static_cast<T *>(N);
400 return FoldingSetTrait<T>::ComputeHash(*TN, TempID);
404 explicit FoldingSet(unsigned Log2InitSize = 6)
405 : FoldingSetImpl(Log2InitSize)
408 typedef FoldingSetIterator<T> iterator;
409 iterator begin() { return iterator(Buckets); }
410 iterator end() { return iterator(Buckets+NumBuckets); }
412 typedef FoldingSetIterator<const T> const_iterator;
413 const_iterator begin() const { return const_iterator(Buckets); }
414 const_iterator end() const { return const_iterator(Buckets+NumBuckets); }
416 typedef FoldingSetBucketIterator<T> bucket_iterator;
418 bucket_iterator bucket_begin(unsigned hash) {
419 return bucket_iterator(Buckets + (hash & (NumBuckets-1)));
422 bucket_iterator bucket_end(unsigned hash) {
423 return bucket_iterator(Buckets + (hash & (NumBuckets-1)), true);
426 /// GetOrInsertNode - If there is an existing simple Node exactly
427 /// equal to the specified node, return it. Otherwise, insert 'N' and
428 /// return it instead.
429 T *GetOrInsertNode(Node *N) {
430 return static_cast<T *>(FoldingSetImpl::GetOrInsertNode(N));
433 /// FindNodeOrInsertPos - Look up the node specified by ID. If it exists,
434 /// return it. If not, return the insertion token that will make insertion
436 T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) {
437 return static_cast<T *>(FoldingSetImpl::FindNodeOrInsertPos(ID, InsertPos));
441 //===----------------------------------------------------------------------===//
442 /// ContextualFoldingSet - This template class is a further refinement
443 /// of FoldingSet which provides a context argument when calling
444 /// Profile on its nodes. Currently, that argument is fixed at
445 /// initialization time.
447 /// T must be a subclass of FoldingSetNode and implement a Profile
448 /// function with signature
449 /// void Profile(llvm::FoldingSetNodeID &, Ctx);
450 template <class T, class Ctx>
451 class ContextualFoldingSet : public FoldingSetImpl {
452 // Unfortunately, this can't derive from FoldingSet<T> because the
453 // construction vtable for FoldingSet<T> requires
454 // FoldingSet<T>::GetNodeProfile to be instantiated, which in turn
455 // requires a single-argument T::Profile().
460 /// GetNodeProfile - Each instantiatation of the FoldingSet needs to provide a
461 /// way to convert nodes into a unique specifier.
462 virtual void GetNodeProfile(FoldingSetImpl::Node *N,
463 FoldingSetNodeID &ID) const {
464 T *TN = static_cast<T *>(N);
465 ContextualFoldingSetTrait<T, Ctx>::Profile(*TN, ID, Context);
467 virtual bool NodeEquals(FoldingSetImpl::Node *N,
468 const FoldingSetNodeID &ID,
469 FoldingSetNodeID &TempID) const {
470 T *TN = static_cast<T *>(N);
471 return ContextualFoldingSetTrait<T, Ctx>::Equals(*TN, ID, TempID, Context);
473 virtual unsigned ComputeNodeHash(FoldingSetImpl::Node *N,
474 FoldingSetNodeID &TempID) const {
475 T *TN = static_cast<T *>(N);
476 return ContextualFoldingSetTrait<T, Ctx>::ComputeHash(*TN, TempID, Context);
480 explicit ContextualFoldingSet(Ctx Context, unsigned Log2InitSize = 6)
481 : FoldingSetImpl(Log2InitSize), Context(Context)
484 Ctx getContext() const { return Context; }
487 typedef FoldingSetIterator<T> iterator;
488 iterator begin() { return iterator(Buckets); }
489 iterator end() { return iterator(Buckets+NumBuckets); }
491 typedef FoldingSetIterator<const T> const_iterator;
492 const_iterator begin() const { return const_iterator(Buckets); }
493 const_iterator end() const { return const_iterator(Buckets+NumBuckets); }
495 typedef FoldingSetBucketIterator<T> bucket_iterator;
497 bucket_iterator bucket_begin(unsigned hash) {
498 return bucket_iterator(Buckets + (hash & (NumBuckets-1)));
501 bucket_iterator bucket_end(unsigned hash) {
502 return bucket_iterator(Buckets + (hash & (NumBuckets-1)), true);
505 /// GetOrInsertNode - If there is an existing simple Node exactly
506 /// equal to the specified node, return it. Otherwise, insert 'N'
507 /// and return it instead.
508 T *GetOrInsertNode(Node *N) {
509 return static_cast<T *>(FoldingSetImpl::GetOrInsertNode(N));
512 /// FindNodeOrInsertPos - Look up the node specified by ID. If it
513 /// exists, return it. If not, return the insertion token that will
514 /// make insertion faster.
515 T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) {
516 return static_cast<T *>(FoldingSetImpl::FindNodeOrInsertPos(ID, InsertPos));
520 //===----------------------------------------------------------------------===//
521 /// FoldingSetIteratorImpl - This is the common iterator support shared by all
522 /// folding sets, which knows how to walk the folding set hash table.
523 class FoldingSetIteratorImpl {
525 FoldingSetNode *NodePtr;
526 FoldingSetIteratorImpl(void **Bucket);
530 bool operator==(const FoldingSetIteratorImpl &RHS) const {
531 return NodePtr == RHS.NodePtr;
533 bool operator!=(const FoldingSetIteratorImpl &RHS) const {
534 return NodePtr != RHS.NodePtr;
540 class FoldingSetIterator : public FoldingSetIteratorImpl {
542 explicit FoldingSetIterator(void **Bucket) : FoldingSetIteratorImpl(Bucket) {}
544 T &operator*() const {
545 return *static_cast<T*>(NodePtr);
548 T *operator->() const {
549 return static_cast<T*>(NodePtr);
552 inline FoldingSetIterator &operator++() { // Preincrement
556 FoldingSetIterator operator++(int) { // Postincrement
557 FoldingSetIterator tmp = *this; ++*this; return tmp;
561 //===----------------------------------------------------------------------===//
562 /// FoldingSetBucketIteratorImpl - This is the common bucket iterator support
563 /// shared by all folding sets, which knows how to walk a particular bucket
564 /// of a folding set hash table.
566 class FoldingSetBucketIteratorImpl {
570 explicit FoldingSetBucketIteratorImpl(void **Bucket);
572 FoldingSetBucketIteratorImpl(void **Bucket, bool)
576 void *Probe = static_cast<FoldingSetNode*>(Ptr)->getNextInBucket();
577 uintptr_t x = reinterpret_cast<uintptr_t>(Probe) & ~0x1;
578 Ptr = reinterpret_cast<void*>(x);
582 bool operator==(const FoldingSetBucketIteratorImpl &RHS) const {
583 return Ptr == RHS.Ptr;
585 bool operator!=(const FoldingSetBucketIteratorImpl &RHS) const {
586 return Ptr != RHS.Ptr;
592 class FoldingSetBucketIterator : public FoldingSetBucketIteratorImpl {
594 explicit FoldingSetBucketIterator(void **Bucket) :
595 FoldingSetBucketIteratorImpl(Bucket) {}
597 FoldingSetBucketIterator(void **Bucket, bool) :
598 FoldingSetBucketIteratorImpl(Bucket, true) {}
600 T &operator*() const { return *static_cast<T*>(Ptr); }
601 T *operator->() const { return static_cast<T*>(Ptr); }
603 inline FoldingSetBucketIterator &operator++() { // Preincrement
607 FoldingSetBucketIterator operator++(int) { // Postincrement
608 FoldingSetBucketIterator tmp = *this; ++*this; return tmp;
612 //===----------------------------------------------------------------------===//
613 /// FoldingSetNodeWrapper - This template class is used to "wrap" arbitrary
614 /// types in an enclosing object so that they can be inserted into FoldingSets.
615 template <typename T>
616 class FoldingSetNodeWrapper : public FoldingSetNode {
619 explicit FoldingSetNodeWrapper(const T &x) : data(x) {}
620 virtual ~FoldingSetNodeWrapper() {}
622 template<typename A1>
623 explicit FoldingSetNodeWrapper(const A1 &a1)
626 template <typename A1, typename A2>
627 explicit FoldingSetNodeWrapper(const A1 &a1, const A2 &a2)
630 template <typename A1, typename A2, typename A3>
631 explicit FoldingSetNodeWrapper(const A1 &a1, const A2 &a2, const A3 &a3)
634 template <typename A1, typename A2, typename A3, typename A4>
635 explicit FoldingSetNodeWrapper(const A1 &a1, const A2 &a2, const A3 &a3,
637 : data(a1,a2,a3,a4) {}
639 template <typename A1, typename A2, typename A3, typename A4, typename A5>
640 explicit FoldingSetNodeWrapper(const A1 &a1, const A2 &a2, const A3 &a3,
641 const A4 &a4, const A5 &a5)
642 : data(a1,a2,a3,a4,a5) {}
645 void Profile(FoldingSetNodeID &ID) { FoldingSetTrait<T>::Profile(data, ID); }
647 T &getValue() { return data; }
648 const T &getValue() const { return data; }
650 operator T&() { return data; }
651 operator const T&() const { return data; }
654 //===----------------------------------------------------------------------===//
655 /// FastFoldingSetNode - This is a subclass of FoldingSetNode which stores
656 /// a FoldingSetNodeID value rather than requiring the node to recompute it
657 /// each time it is needed. This trades space for speed (which can be
658 /// significant if the ID is long), and it also permits nodes to drop
659 /// information that would otherwise only be required for recomputing an ID.
660 class FastFoldingSetNode : public FoldingSetNode {
661 FoldingSetNodeID FastID;
663 explicit FastFoldingSetNode(const FoldingSetNodeID &ID) : FastID(ID) {}
665 void Profile(FoldingSetNodeID &ID) const {
666 ID.AddNodeID(FastID);
670 //===----------------------------------------------------------------------===//
671 // Partial specializations of FoldingSetTrait.
673 template<typename T> struct FoldingSetTrait<T*> {
674 static inline void Profile(T *X, FoldingSetNodeID &ID) {
678 } // End of namespace llvm.