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Diffstat (limited to 'include/llvm/ADT/FoldingSet.h')
| -rw-r--r-- | include/llvm/ADT/FoldingSet.h | 461 |
1 files changed, 461 insertions, 0 deletions
diff --git a/include/llvm/ADT/FoldingSet.h b/include/llvm/ADT/FoldingSet.h new file mode 100644 index 0000000..e31e112 --- /dev/null +++ b/include/llvm/ADT/FoldingSet.h @@ -0,0 +1,461 @@ +//===-- llvm/ADT/FoldingSet.h - Uniquing Hash Set ---------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// +// +// This file defines a hash set that can be used to remove duplication of nodes +// in a graph. This code was originally created by Chris Lattner for use with +// SelectionDAGCSEMap, but was isolated to provide use across the llvm code set. +// +//===----------------------------------------------------------------------===// + +#ifndef LLVM_ADT_FOLDINGSET_H +#define LLVM_ADT_FOLDINGSET_H + +#include "llvm/Support/DataTypes.h" +#include "llvm/ADT/SmallVector.h" +#include <string> +#include <iterator> + +namespace llvm { + class APFloat; + class APInt; + +/// This folding set used for two purposes: +/// 1. Given information about a node we want to create, look up the unique +/// instance of the node in the set. If the node already exists, return +/// it, otherwise return the bucket it should be inserted into. +/// 2. Given a node that has already been created, remove it from the set. +/// +/// This class is implemented as a single-link chained hash table, where the +/// "buckets" are actually the nodes themselves (the next pointer is in the +/// node). The last node points back to the bucket to simplify node removal. +/// +/// Any node that is to be included in the folding set must be a subclass of +/// FoldingSetNode. The node class must also define a Profile method used to +/// establish the unique bits of data for the node. The Profile method is +/// passed a FoldingSetNodeID object which is used to gather the bits. Just +/// call one of the Add* functions defined in the FoldingSetImpl::NodeID class. +/// NOTE: That the folding set does not own the nodes and it is the +/// responsibility of the user to dispose of the nodes. +/// +/// Eg. +/// class MyNode : public FoldingSetNode { +/// private: +/// std::string Name; +/// unsigned Value; +/// public: +/// MyNode(const char *N, unsigned V) : Name(N), Value(V) {} +/// ... +/// void Profile(FoldingSetNodeID &ID) { +/// ID.AddString(Name); +/// ID.AddInteger(Value); +/// } +/// ... +/// }; +/// +/// To define the folding set itself use the FoldingSet template; +/// +/// Eg. +/// FoldingSet<MyNode> MyFoldingSet; +/// +/// Four public methods are available to manipulate the folding set; +/// +/// 1) If you have an existing node that you want add to the set but unsure +/// that the node might already exist then call; +/// +/// MyNode *M = MyFoldingSet.GetOrInsertNode(N); +/// +/// If The result is equal to the input then the node has been inserted. +/// Otherwise, the result is the node existing in the folding set, and the +/// input can be discarded (use the result instead.) +/// +/// 2) If you are ready to construct a node but want to check if it already +/// exists, then call FindNodeOrInsertPos with a FoldingSetNodeID of the bits to +/// check; +/// +/// FoldingSetNodeID ID; +/// ID.AddString(Name); +/// ID.AddInteger(Value); +/// void *InsertPoint; +/// +/// MyNode *M = MyFoldingSet.FindNodeOrInsertPos(ID, InsertPoint); +/// +/// If found then M with be non-NULL, else InsertPoint will point to where it +/// should be inserted using InsertNode. +/// +/// 3) If you get a NULL result from FindNodeOrInsertPos then you can as a new +/// node with FindNodeOrInsertPos; +/// +/// InsertNode(N, InsertPoint); +/// +/// 4) Finally, if you want to remove a node from the folding set call; +/// +/// bool WasRemoved = RemoveNode(N); +/// +/// The result indicates whether the node existed in the folding set. + +class FoldingSetNodeID; + +//===----------------------------------------------------------------------===// +/// FoldingSetImpl - Implements the folding set functionality. The main +/// structure is an array of buckets. Each bucket is indexed by the hash of +/// the nodes it contains. The bucket itself points to the nodes contained +/// in the bucket via a singly linked list. The last node in the list points +/// back to the bucket to facilitate node removal. +/// +class FoldingSetImpl { +protected: + /// Buckets - Array of bucket chains. + /// + void **Buckets; + + /// NumBuckets - Length of the Buckets array. Always a power of 2. + /// + unsigned NumBuckets; + + /// NumNodes - Number of nodes in the folding set. Growth occurs when NumNodes + /// is greater than twice the number of buckets. + unsigned NumNodes; + +public: + explicit FoldingSetImpl(unsigned Log2InitSize = 6); + virtual ~FoldingSetImpl(); + + //===--------------------------------------------------------------------===// + /// Node - This class is used to maintain the singly linked bucket list in + /// a folding set. + /// + class Node { + private: + // NextInFoldingSetBucket - next link in the bucket list. + void *NextInFoldingSetBucket; + + public: + + Node() : NextInFoldingSetBucket(0) {} + + // Accessors + void *getNextInBucket() const { return NextInFoldingSetBucket; } + void SetNextInBucket(void *N) { NextInFoldingSetBucket = N; } + }; + + /// clear - Remove all nodes from the folding set. + void clear(); + + /// RemoveNode - Remove a node from the folding set, returning true if one + /// was removed or false if the node was not in the folding set. + bool RemoveNode(Node *N); + + /// GetOrInsertNode - If there is an existing simple Node exactly + /// equal to the specified node, return it. Otherwise, insert 'N' and return + /// it instead. + Node *GetOrInsertNode(Node *N); + + /// FindNodeOrInsertPos - Look up the node specified by ID. If it exists, + /// return it. If not, return the insertion token that will make insertion + /// faster. + Node *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos); + + /// InsertNode - Insert the specified node into the folding set, knowing that + /// it is not already in the folding set. InsertPos must be obtained from + /// FindNodeOrInsertPos. + void InsertNode(Node *N, void *InsertPos); + + /// size - Returns the number of nodes in the folding set. + unsigned size() const { return NumNodes; } + + /// empty - Returns true if there are no nodes in the folding set. + bool empty() const { return NumNodes == 0; } + +private: + + /// GrowHashTable - Double the size of the hash table and rehash everything. + /// + void GrowHashTable(); + +protected: + + /// GetNodeProfile - Instantiations of the FoldingSet template implement + /// this function to gather data bits for the given node. + virtual void GetNodeProfile(FoldingSetNodeID &ID, Node *N) const = 0; +}; + +//===----------------------------------------------------------------------===// +/// FoldingSetTrait - This trait class is used to define behavior of how +/// to "profile" (in the FoldingSet parlance) an object of a given type. +/// The default behavior is to invoke a 'Profile' method on an object, but +/// through template specialization the behavior can be tailored for specific +/// types. Combined with the FoldingSetNodeWrapper classs, one can add objects +/// to FoldingSets that were not originally designed to have that behavior. +/// +template<typename T> struct FoldingSetTrait { + static inline void Profile(const T& X, FoldingSetNodeID& ID) { X.Profile(ID);} + static inline void Profile(T& X, FoldingSetNodeID& ID) { X.Profile(ID); } +}; + +//===--------------------------------------------------------------------===// +/// FoldingSetNodeID - This class is used to gather all the unique data bits of +/// a node. When all the bits are gathered this class is used to produce a +/// hash value for the node. +/// +class FoldingSetNodeID { + /// Bits - Vector of all the data bits that make the node unique. + /// Use a SmallVector to avoid a heap allocation in the common case. + SmallVector<unsigned, 32> Bits; + +public: + FoldingSetNodeID() {} + + /// getRawData - Return the ith entry in the Bits data. + /// + unsigned getRawData(unsigned i) const { + return Bits[i]; + } + + /// Add* - Add various data types to Bit data. + /// + void AddPointer(const void *Ptr); + void AddInteger(signed I); + void AddInteger(unsigned I); + void AddInteger(long I); + void AddInteger(unsigned long I); + void AddInteger(long long I); + void AddInteger(unsigned long long I); + void AddBoolean(bool B) { AddInteger(B ? 1U : 0U); } + void AddString(const char* String, const char* End); + void AddString(const std::string &String); + void AddString(const char* String); + + template <typename T> + inline void Add(const T& x) { FoldingSetTrait<T>::Profile(x, *this); } + + /// clear - Clear the accumulated profile, allowing this FoldingSetNodeID + /// object to be used to compute a new profile. + inline void clear() { Bits.clear(); } + + /// ComputeHash - Compute a strong hash value for this FoldingSetNodeID, used + /// to lookup the node in the FoldingSetImpl. + unsigned ComputeHash() const; + + /// operator== - Used to compare two nodes to each other. + /// + bool operator==(const FoldingSetNodeID &RHS) const; +}; + +// Convenience type to hide the implementation of the folding set. +typedef FoldingSetImpl::Node FoldingSetNode; +template<class T> class FoldingSetIterator; +template<class T> class FoldingSetBucketIterator; + +//===----------------------------------------------------------------------===// +/// FoldingSet - This template class is used to instantiate a specialized +/// implementation of the folding set to the node class T. T must be a +/// subclass of FoldingSetNode and implement a Profile function. +/// +template<class T> class FoldingSet : public FoldingSetImpl { +private: + /// GetNodeProfile - Each instantiatation of the FoldingSet needs to provide a + /// way to convert nodes into a unique specifier. + virtual void GetNodeProfile(FoldingSetNodeID &ID, Node *N) const { + T *TN = static_cast<T *>(N); + FoldingSetTrait<T>::Profile(*TN,ID); + } + +public: + explicit FoldingSet(unsigned Log2InitSize = 6) + : FoldingSetImpl(Log2InitSize) + {} + + typedef FoldingSetIterator<T> iterator; + iterator begin() { return iterator(Buckets); } + iterator end() { return iterator(Buckets+NumBuckets); } + + typedef FoldingSetIterator<const T> const_iterator; + const_iterator begin() const { return const_iterator(Buckets); } + const_iterator end() const { return const_iterator(Buckets+NumBuckets); } + + typedef FoldingSetBucketIterator<T> bucket_iterator; + + bucket_iterator bucket_begin(unsigned hash) { + return bucket_iterator(Buckets + (hash & (NumBuckets-1))); + } + + bucket_iterator bucket_end(unsigned hash) { + return bucket_iterator(Buckets + (hash & (NumBuckets-1)), true); + } + + /// GetOrInsertNode - If there is an existing simple Node exactly + /// equal to the specified node, return it. Otherwise, insert 'N' and + /// return it instead. + T *GetOrInsertNode(Node *N) { + return static_cast<T *>(FoldingSetImpl::GetOrInsertNode(N)); + } + + /// FindNodeOrInsertPos - Look up the node specified by ID. If it exists, + /// return it. If not, return the insertion token that will make insertion + /// faster. + T *FindNodeOrInsertPos(const FoldingSetNodeID &ID, void *&InsertPos) { + return static_cast<T *>(FoldingSetImpl::FindNodeOrInsertPos(ID, InsertPos)); + } +}; + +//===----------------------------------------------------------------------===// +/// FoldingSetIteratorImpl - This is the common iterator support shared by all +/// folding sets, which knows how to walk the folding set hash table. +class FoldingSetIteratorImpl { +protected: + FoldingSetNode *NodePtr; + FoldingSetIteratorImpl(void **Bucket); + void advance(); + +public: + bool operator==(const FoldingSetIteratorImpl &RHS) const { + return NodePtr == RHS.NodePtr; + } + bool operator!=(const FoldingSetIteratorImpl &RHS) const { + return NodePtr != RHS.NodePtr; + } +}; + + +template<class T> +class FoldingSetIterator : public FoldingSetIteratorImpl { +public: + explicit FoldingSetIterator(void **Bucket) : FoldingSetIteratorImpl(Bucket) {} + + T &operator*() const { + return *static_cast<T*>(NodePtr); + } + + T *operator->() const { + return static_cast<T*>(NodePtr); + } + + inline FoldingSetIterator& operator++() { // Preincrement + advance(); + return *this; + } + FoldingSetIterator operator++(int) { // Postincrement + FoldingSetIterator tmp = *this; ++*this; return tmp; + } +}; + +//===----------------------------------------------------------------------===// +/// FoldingSetBucketIteratorImpl - This is the common bucket iterator support +/// shared by all folding sets, which knows how to walk a particular bucket +/// of a folding set hash table. + +class FoldingSetBucketIteratorImpl { +protected: + void *Ptr; + + explicit FoldingSetBucketIteratorImpl(void **Bucket); + + FoldingSetBucketIteratorImpl(void **Bucket, bool) + : Ptr(Bucket) {} + + void advance() { + void *Probe = static_cast<FoldingSetNode*>(Ptr)->getNextInBucket(); + uintptr_t x = reinterpret_cast<uintptr_t>(Probe) & ~0x1; + Ptr = reinterpret_cast<void*>(x); + } + +public: + bool operator==(const FoldingSetBucketIteratorImpl &RHS) const { + return Ptr == RHS.Ptr; + } + bool operator!=(const FoldingSetBucketIteratorImpl &RHS) const { + return Ptr != RHS.Ptr; + } +}; + + +template<class T> +class FoldingSetBucketIterator : public FoldingSetBucketIteratorImpl { +public: + explicit FoldingSetBucketIterator(void **Bucket) : + FoldingSetBucketIteratorImpl(Bucket) {} + + FoldingSetBucketIterator(void **Bucket, bool) : + FoldingSetBucketIteratorImpl(Bucket, true) {} + + T& operator*() const { return *static_cast<T*>(Ptr); } + T* operator->() const { return static_cast<T*>(Ptr); } + + inline FoldingSetBucketIterator& operator++() { // Preincrement + advance(); + return *this; + } + FoldingSetBucketIterator operator++(int) { // Postincrement + FoldingSetBucketIterator tmp = *this; ++*this; return tmp; + } +}; + +//===----------------------------------------------------------------------===// +/// FoldingSetNodeWrapper - This template class is used to "wrap" arbitrary +/// types in an enclosing object so that they can be inserted into FoldingSets. +template <typename T> +class FoldingSetNodeWrapper : public FoldingSetNode { + T data; +public: + explicit FoldingSetNodeWrapper(const T& x) : data(x) {} + virtual ~FoldingSetNodeWrapper() {} + + template<typename A1> + explicit FoldingSetNodeWrapper(const A1& a1) + : data(a1) {} + + template <typename A1, typename A2> + explicit FoldingSetNodeWrapper(const A1& a1, const A2& a2) + : data(a1,a2) {} + + template <typename A1, typename A2, typename A3> + explicit FoldingSetNodeWrapper(const A1& a1, const A2& a2, const A3& a3) + : data(a1,a2,a3) {} + + template <typename A1, typename A2, typename A3, typename A4> + explicit FoldingSetNodeWrapper(const A1& a1, const A2& a2, const A3& a3, + const A4& a4) + : data(a1,a2,a3,a4) {} + + template <typename A1, typename A2, typename A3, typename A4, typename A5> + explicit FoldingSetNodeWrapper(const A1& a1, const A2& a2, const A3& a3, + const A4& a4, const A5& a5) + : data(a1,a2,a3,a4,a5) {} + + + void Profile(FoldingSetNodeID& ID) { FoldingSetTrait<T>::Profile(data, ID); } + + T& getValue() { return data; } + const T& getValue() const { return data; } + + operator T&() { return data; } + operator const T&() const { return data; } +}; + +//===----------------------------------------------------------------------===// +// Partial specializations of FoldingSetTrait. + +template<typename T> struct FoldingSetTrait<T*> { + static inline void Profile(const T* X, FoldingSetNodeID& ID) { + ID.AddPointer(X); + } + static inline void Profile(T* X, FoldingSetNodeID& ID) { + ID.AddPointer(X); + } +}; + +template<typename T> struct FoldingSetTrait<const T*> { + static inline void Profile(const T* X, FoldingSetNodeID& ID) { + ID.AddPointer(X); + } +}; + +} // End of namespace llvm. + +#endif |
