X-Git-Url: http://plrg.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FADT%2FImmutableSet.h;h=87026f019fec93c500e7a713d5913983cd9cb4c1;hb=df7186636e51e63281bd318234b7d97f25efe491;hp=7999bb5967218c946cee5a31f19cdd9c1e184844;hpb=e509e7a17819f808dabb815474eb8c04540de7b3;p=oota-llvm.git diff --git a/include/llvm/ADT/ImmutableSet.h b/include/llvm/ADT/ImmutableSet.h index 7999bb59672..87026f019fe 100644 --- a/include/llvm/ADT/ImmutableSet.h +++ b/include/llvm/ADT/ImmutableSet.h @@ -11,25 +11,31 @@ // //===----------------------------------------------------------------------===// -#ifndef LLVM_ADT_IMSET_H -#define LLVM_ADT_IMSET_H +#ifndef LLVM_ADT_IMMUTABLESET_H +#define LLVM_ADT_IMMUTABLESET_H -#include "llvm/Support/Allocator.h" +#include "llvm/ADT/DenseMap.h" #include "llvm/ADT/FoldingSet.h" +#include "llvm/Support/Allocator.h" +#include "llvm/Support/DataTypes.h" +#include "llvm/Support/ErrorHandling.h" #include +#include +#include namespace llvm { - -//===----------------------------------------------------------------------===// + +//===----------------------------------------------------------------------===// // Immutable AVL-Tree Definition. //===----------------------------------------------------------------------===// template class ImutAVLFactory; - +template class ImutIntervalAVLFactory; template class ImutAVLTreeInOrderIterator; - +template class ImutAVLTreeGenericIterator; + template -class ImutAVLTree : public FoldingSetNode { +class ImutAVLTree { public: typedef typename ImutInfo::key_type_ref key_type_ref; typedef typename ImutInfo::value_type value_type; @@ -37,41 +43,37 @@ public: typedef ImutAVLFactory Factory; friend class ImutAVLFactory; - + friend class ImutIntervalAVLFactory; + + friend class ImutAVLTreeGenericIterator; + typedef ImutAVLTreeInOrderIterator iterator; - - //===----------------------------------------------------===// + + //===----------------------------------------------------===// // Public Interface. - //===----------------------------------------------------===// - - /// getLeft - Returns a pointer to the left subtree. This value + //===----------------------------------------------------===// + + /// Return a pointer to the left subtree. This value /// is NULL if there is no left subtree. - ImutAVLTree* getLeft() const { - assert (!isMutable() && "Node is incorrectly marked mutable."); - - return reinterpret_cast(Left); - } - - /// getRight - Returns a pointer to the right subtree. This value is + ImutAVLTree *getLeft() const { return left; } + + /// Return a pointer to the right subtree. This value is /// NULL if there is no right subtree. - ImutAVLTree* getRight() const { return Right; } - - + ImutAVLTree *getRight() const { return right; } + /// getHeight - Returns the height of the tree. A tree with no subtrees /// has a height of 1. - unsigned getHeight() const { return Height; } - + unsigned getHeight() const { return height; } + /// getValue - Returns the data value associated with the tree node. - const value_type& getValue() const { return Value; } - + const value_type& getValue() const { return value; } + /// find - Finds the subtree associated with the specified key value. /// This method returns NULL if no matching subtree is found. ImutAVLTree* find(key_type_ref K) { ImutAVLTree *T = this; - while (T) { key_type_ref CurrentKey = ImutInfo::KeyOfValue(T->getValue()); - if (ImutInfo::isEqual(K,CurrentKey)) return T; else if (ImutInfo::isLess(K,CurrentKey)) @@ -79,286 +81,375 @@ public: else T = T->getRight(); } - - return NULL; + return nullptr; } - + + /// getMaxElement - Find the subtree associated with the highest ranged + /// key value. + ImutAVLTree* getMaxElement() { + ImutAVLTree *T = this; + ImutAVLTree *Right = T->getRight(); + while (Right) { T = Right; Right = T->getRight(); } + return T; + } + /// size - Returns the number of nodes in the tree, which includes /// both leaves and non-leaf nodes. unsigned size() const { unsigned n = 1; - - if (const ImutAVLTree* L = getLeft()) n += L->size(); - if (const ImutAVLTree* R = getRight()) n += R->size(); - + if (const ImutAVLTree* L = getLeft()) + n += L->size(); + if (const ImutAVLTree* R = getRight()) + n += R->size(); return n; } - + /// begin - Returns an iterator that iterates over the nodes of the tree /// in an inorder traversal. The returned iterator thus refers to the /// the tree node with the minimum data element. iterator begin() const { return iterator(this); } - + /// end - Returns an iterator for the tree that denotes the end of an /// inorder traversal. iterator end() const { return iterator(); } - + + bool isElementEqual(value_type_ref V) const { + // Compare the keys. + if (!ImutInfo::isEqual(ImutInfo::KeyOfValue(getValue()), + ImutInfo::KeyOfValue(V))) + return false; + + // Also compare the data values. + if (!ImutInfo::isDataEqual(ImutInfo::DataOfValue(getValue()), + ImutInfo::DataOfValue(V))) + return false; + + return true; + } + + bool isElementEqual(const ImutAVLTree* RHS) const { + return isElementEqual(RHS->getValue()); + } + /// isEqual - Compares two trees for structural equality and returns true /// if they are equal. This worst case performance of this operation is // linear in the sizes of the trees. bool isEqual(const ImutAVLTree& RHS) const { if (&RHS == this) return true; - + iterator LItr = begin(), LEnd = end(); iterator RItr = RHS.begin(), REnd = RHS.end(); - + while (LItr != LEnd && RItr != REnd) { - if (*LItr == *RItr) { - LItr.SkipSubTree(); - RItr.SkipSubTree(); + if (&*LItr == &*RItr) { + LItr.skipSubTree(); + RItr.skipSubTree(); continue; } - - // Compare the keys. - if (!ImutInfo::isEqual(ImutInfo::KeyOfValue(LItr->getValue()), - ImutInfo::KeyOfValue(RItr->getValue()))) - return false; - - // Also compare the data values. - if (!ImutInfo::isDataEqual(ImutInfo::DataOfValue(LItr->getValue()), - ImutInfo::DataOfValue(RItr->getValue()))) + + if (!LItr->isElementEqual(&*RItr)) return false; - + ++LItr; ++RItr; } - + return LItr == LEnd && RItr == REnd; } /// isNotEqual - Compares two trees for structural inequality. Performance /// is the same is isEqual. bool isNotEqual(const ImutAVLTree& RHS) const { return !isEqual(RHS); } - + /// contains - Returns true if this tree contains a subtree (node) that /// has an data element that matches the specified key. Complexity /// is logarithmic in the size of the tree. - bool contains(const key_type_ref K) { return (bool) find(K); } - + bool contains(key_type_ref K) { return (bool) find(K); } + /// foreach - A member template the accepts invokes operator() on a functor /// object (specifed by Callback) for every node/subtree in the tree. /// Nodes are visited using an inorder traversal. template void foreach(Callback& C) { - if (ImutAVLTree* L = getLeft()) L->foreach(C); - - C(Value); - - if (ImutAVLTree* R = getRight()) R->foreach(C); - } - - /// verify - A utility method that checks that the balancing and + if (ImutAVLTree* L = getLeft()) + L->foreach(C); + + C(value); + + if (ImutAVLTree* R = getRight()) + R->foreach(C); + } + + /// validateTree - A utility method that checks that the balancing and /// ordering invariants of the tree are satisifed. It is a recursive /// method that returns the height of the tree, which is then consumed - /// by the enclosing verify call. External callers should ignore the + /// by the enclosing validateTree call. External callers should ignore the /// return value. An invalid tree will cause an assertion to fire in /// a debug build. - unsigned verify() const { - unsigned HL = getLeft() ? getLeft()->verify() : 0; - unsigned HR = getRight() ? getRight()->verify() : 0; - - assert (getHeight() == ( HL > HR ? HL : HR ) + 1 - && "Height calculation wrong."); - - assert ((HL > HR ? HL-HR : HR-HL) <= 2 - && "Balancing invariant violated."); - - - assert (!getLeft() - || ImutInfo::isLess(ImutInfo::KeyOfValue(getLeft()->getValue()), - ImutInfo::KeyOfValue(getValue())) - && "Value in left child is not less that current value."); - - - assert (!getRight() - || ImutInfo::isLess(ImutInfo::KeyOfValue(getValue()), - ImutInfo::KeyOfValue(getRight()->getValue())) - && "Current value is not less that value of right child."); - + unsigned validateTree() const { + unsigned HL = getLeft() ? getLeft()->validateTree() : 0; + unsigned HR = getRight() ? getRight()->validateTree() : 0; + (void) HL; + (void) HR; + + assert(getHeight() == ( HL > HR ? HL : HR ) + 1 + && "Height calculation wrong"); + + assert((HL > HR ? HL-HR : HR-HL) <= 2 + && "Balancing invariant violated"); + + assert((!getLeft() || + ImutInfo::isLess(ImutInfo::KeyOfValue(getLeft()->getValue()), + ImutInfo::KeyOfValue(getValue()))) && + "Value in left child is not less that current value"); + + + assert(!(getRight() || + ImutInfo::isLess(ImutInfo::KeyOfValue(getValue()), + ImutInfo::KeyOfValue(getRight()->getValue()))) && + "Current value is not less that value of right child"); + return getHeight(); - } - - //===----------------------------------------------------===// - // Internal Values. + } + //===----------------------------------------------------===// - -private: - uintptr_t Left; - ImutAVLTree* Right; - unsigned Height; - value_type Value; - - //===----------------------------------------------------===// - // Profiling or FoldingSet. + // Internal values. //===----------------------------------------------------===// private: + Factory *factory; + ImutAVLTree *left; + ImutAVLTree *right; + ImutAVLTree *prev; + ImutAVLTree *next; - /// Profile - Generates a FoldingSet profile for a tree node before it is - /// created. This is used by the ImutAVLFactory when creating - /// trees. - static inline - void Profile(FoldingSetNodeID& ID, ImutAVLTree* L, ImutAVLTree* R, - value_type_ref V) { - ID.AddPointer(L); - ID.AddPointer(R); - ImutInfo::Profile(ID,V); - } - -public: + unsigned height : 28; + unsigned IsMutable : 1; + unsigned IsDigestCached : 1; + unsigned IsCanonicalized : 1; - /// Profile - Generates a FoldingSet profile for an existing tree node. - void Profile(FoldingSetNodeID& ID) { - Profile(ID,getSafeLeft(),getRight(),getValue()); - } - - //===----------------------------------------------------===// + value_type value; + uint32_t digest; + uint32_t refCount; + + //===----------------------------------------------------===// // Internal methods (node manipulation; used by Factory). //===----------------------------------------------------===// - + private: - - enum { Mutable = 0x1 }; - /// ImutAVLTree - Internal constructor that is only called by /// ImutAVLFactory. - ImutAVLTree(ImutAVLTree* l, ImutAVLTree* r, value_type_ref v, unsigned height) - : Left(reinterpret_cast(l) | Mutable), - Right(r), Height(height), Value(v) {} - - + ImutAVLTree(Factory *f, ImutAVLTree* l, ImutAVLTree* r, value_type_ref v, + unsigned height) + : factory(f), left(l), right(r), prev(nullptr), next(nullptr), + height(height), IsMutable(true), IsDigestCached(false), + IsCanonicalized(0), value(v), digest(0), refCount(0) + { + if (left) left->retain(); + if (right) right->retain(); + } + /// isMutable - Returns true if the left and right subtree references /// (as well as height) can be changed. If this method returns false, /// the tree is truly immutable. Trees returned from an ImutAVLFactory /// object should always have this method return true. Further, if this /// method returns false for an instance of ImutAVLTree, all subtrees /// will also have this method return false. The converse is not true. - bool isMutable() const { return Left & Mutable; } - - /// getSafeLeft - Returns the pointer to the left tree by always masking - /// out the mutable bit. This is used internally by ImutAVLFactory, - /// as no trees returned to the client should have the mutable flag set. - ImutAVLTree* getSafeLeft() const { - return reinterpret_cast(Left & ~Mutable); - } - - //===----------------------------------------------------===// + bool isMutable() const { return IsMutable; } + + /// hasCachedDigest - Returns true if the digest for this tree is cached. + /// This can only be true if the tree is immutable. + bool hasCachedDigest() const { return IsDigestCached; } + + //===----------------------------------------------------===// // Mutating operations. A tree root can be manipulated as - // long as its reference has not "escaped" from internal + // long as its reference has not "escaped" from internal // methods of a factory object (see below). When a tree - // pointer is externally viewable by client code, the - // internal "mutable bit" is cleared to mark the tree + // pointer is externally viewable by client code, the + // internal "mutable bit" is cleared to mark the tree // immutable. Note that a tree that still has its mutable // bit set may have children (subtrees) that are themselves // immutable. //===----------------------------------------------------===// - - - /// MarkImmutable - Clears the mutable flag for a tree. After this happens, - /// it is an error to call setLeft(), setRight(), and setHeight(). It - /// is also then safe to call getLeft() instead of getSafeLeft(). - void MarkImmutable() { - assert (isMutable() && "Mutable flag already removed."); - Left &= ~Mutable; - } - - /// setLeft - Changes the reference of the left subtree. Used internally - /// by ImutAVLFactory. - void setLeft(ImutAVLTree* NewLeft) { - assert (isMutable() && - "Only a mutable tree can have its left subtree changed."); - - Left = reinterpret_cast(NewLeft) | Mutable; - } - - /// setRight - Changes the reference of the right subtree. Used internally - /// by ImutAVLFactory. - void setRight(ImutAVLTree* NewRight) { - assert (isMutable() && - "Only a mutable tree can have its right subtree changed."); - - Right = NewRight; - } - + + /// markImmutable - Clears the mutable flag for a tree. After this happens, + /// it is an error to call setLeft(), setRight(), and setHeight(). + void markImmutable() { + assert(isMutable() && "Mutable flag already removed."); + IsMutable = false; + } + + /// markedCachedDigest - Clears the NoCachedDigest flag for a tree. + void markedCachedDigest() { + assert(!hasCachedDigest() && "NoCachedDigest flag already removed."); + IsDigestCached = true; + } + /// setHeight - Changes the height of the tree. Used internally by /// ImutAVLFactory. void setHeight(unsigned h) { - assert (isMutable() && "Only a mutable tree can have its height changed."); - Height = h; + assert(isMutable() && "Only a mutable tree can have its height changed."); + height = h; + } + + static uint32_t computeDigest(ImutAVLTree *L, ImutAVLTree *R, + value_type_ref V) { + uint32_t digest = 0; + + if (L) + digest += L->computeDigest(); + + // Compute digest of stored data. + FoldingSetNodeID ID; + ImutInfo::Profile(ID,V); + digest += ID.ComputeHash(); + + if (R) + digest += R->computeDigest(); + + return digest; + } + + uint32_t computeDigest() { + // Check the lowest bit to determine if digest has actually been + // pre-computed. + if (hasCachedDigest()) + return digest; + + uint32_t X = computeDigest(getLeft(), getRight(), getValue()); + digest = X; + markedCachedDigest(); + return X; + } + + //===----------------------------------------------------===// + // Reference count operations. + //===----------------------------------------------------===// + +public: + void retain() { ++refCount; } + void release() { + assert(refCount > 0); + if (--refCount == 0) + destroy(); + } + void destroy() { + if (left) + left->release(); + if (right) + right->release(); + if (IsCanonicalized) { + if (next) + next->prev = prev; + + if (prev) + prev->next = next; + else + factory->Cache[factory->maskCacheIndex(computeDigest())] = next; + } + + // We need to clear the mutability bit in case we are + // destroying the node as part of a sweep in ImutAVLFactory::recoverNodes(). + IsMutable = false; + factory->freeNodes.push_back(this); } }; -//===----------------------------------------------------------------------===// +//===----------------------------------------------------------------------===// // Immutable AVL-Tree Factory class. //===----------------------------------------------------------------------===// -template +template class ImutAVLFactory { + friend class ImutAVLTree; typedef ImutAVLTree TreeTy; typedef typename TreeTy::value_type_ref value_type_ref; typedef typename TreeTy::key_type_ref key_type_ref; - - typedef FoldingSet CacheTy; - - CacheTy Cache; - BumpPtrAllocator Allocator; - - //===--------------------------------------------------===// + + typedef DenseMap CacheTy; + + CacheTy Cache; + uintptr_t Allocator; + std::vector createdNodes; + std::vector freeNodes; + + bool ownsAllocator() const { + return Allocator & 0x1 ? false : true; + } + + BumpPtrAllocator& getAllocator() const { + return *reinterpret_cast(Allocator & ~0x1); + } + + //===--------------------------------------------------===// // Public interface. //===--------------------------------------------------===// - + public: - ImutAVLFactory() {} - - TreeTy* Add(TreeTy* T, value_type_ref V) { - T = Add_internal(V,T); - MarkImmutable(T); + ImutAVLFactory() + : Allocator(reinterpret_cast(new BumpPtrAllocator())) {} + + ImutAVLFactory(BumpPtrAllocator& Alloc) + : Allocator(reinterpret_cast(&Alloc) | 0x1) {} + + ~ImutAVLFactory() { + if (ownsAllocator()) delete &getAllocator(); + } + + TreeTy* add(TreeTy* T, value_type_ref V) { + T = add_internal(V,T); + markImmutable(T); + recoverNodes(); return T; } - - TreeTy* Remove(TreeTy* T, key_type_ref V) { - T = Remove_internal(V,T); - MarkImmutable(T); + + TreeTy* remove(TreeTy* T, key_type_ref V) { + T = remove_internal(V,T); + markImmutable(T); + recoverNodes(); return T; } - - TreeTy* GetEmptyTree() const { return NULL; } - - BumpPtrAllocator& getAllocator() { return Allocator; } - - //===--------------------------------------------------===// + + TreeTy* getEmptyTree() const { return nullptr; } + +protected: + + //===--------------------------------------------------===// // A bunch of quick helper functions used for reasoning // about the properties of trees and their children. // These have succinct names so that the balancing code // is as terse (and readable) as possible. //===--------------------------------------------------===// -private: - - bool isEmpty(TreeTy* T) const { return !T; } - unsigned Height(TreeTy* T) const { return T ? T->getHeight() : 0; } - TreeTy* Left(TreeTy* T) const { return T->getSafeLeft(); } - TreeTy* Right(TreeTy* T) const { return T->getRight(); } - value_type_ref Value(TreeTy* T) const { return T->Value; } - - unsigned IncrementHeight(TreeTy* L, TreeTy* R) const { - unsigned hl = Height(L); - unsigned hr = Height(R); - return ( hl > hr ? hl : hr ) + 1; - } - - //===--------------------------------------------------===// - // "CreateNode" is used to generate new tree roots that link + + bool isEmpty(TreeTy* T) const { return !T; } + unsigned getHeight(TreeTy* T) const { return T ? T->getHeight() : 0; } + TreeTy* getLeft(TreeTy* T) const { return T->getLeft(); } + TreeTy* getRight(TreeTy* T) const { return T->getRight(); } + value_type_ref getValue(TreeTy* T) const { return T->value; } + + // Make sure the index is not the Tombstone or Entry key of the DenseMap. + static unsigned maskCacheIndex(unsigned I) { return (I & ~0x02); } + + unsigned incrementHeight(TreeTy* L, TreeTy* R) const { + unsigned hl = getHeight(L); + unsigned hr = getHeight(R); + return (hl > hr ? hl : hr) + 1; + } + + static bool compareTreeWithSection(TreeTy* T, + typename TreeTy::iterator& TI, + typename TreeTy::iterator& TE) { + typename TreeTy::iterator I = T->begin(), E = T->end(); + for ( ; I!=E ; ++I, ++TI) { + if (TI == TE || !I->isElementEqual(&*TI)) + return false; + } + return true; + } + + //===--------------------------------------------------===// + // "createNode" is used to generate new tree roots that link // to other trees. The functon may also simply move links // in an existing root if that root is still marked mutable. // This is necessary because otherwise our balancing code @@ -366,200 +457,232 @@ private: // then discarded later before the finished tree is // returned to the caller. //===--------------------------------------------------===// - - TreeTy* CreateNode(TreeTy* L, value_type_ref V, TreeTy* R) { - FoldingSetNodeID ID; - TreeTy::Profile(ID,L,R,V); - void* InsertPos; - - if (TreeTy* T = Cache.FindNodeOrInsertPos(ID,InsertPos)) - return T; - - assert (InsertPos != NULL); - - // Allocate the new tree node and insert it into the cache. - TreeTy* T = (TreeTy*) Allocator.Allocate(); - new (T) TreeTy(L,R,V,IncrementHeight(L,R)); - Cache.InsertNode(T,InsertPos); - - return T; - } - - TreeTy* CreateNode(TreeTy* L, TreeTy* OldTree, TreeTy* R) { - assert (!isEmpty(OldTree)); - - if (OldTree->isMutable()) { - OldTree->setLeft(L); - OldTree->setRight(R); - OldTree->setHeight(IncrementHeight(L,R)); - return OldTree; + + TreeTy* createNode(TreeTy* L, value_type_ref V, TreeTy* R) { + BumpPtrAllocator& A = getAllocator(); + TreeTy* T; + if (!freeNodes.empty()) { + T = freeNodes.back(); + freeNodes.pop_back(); + assert(T != L); + assert(T != R); + } else { + T = (TreeTy*) A.Allocate(); + } + new (T) TreeTy(this, L, R, V, incrementHeight(L,R)); + createdNodes.push_back(T); + return T; + } + + TreeTy* createNode(TreeTy* newLeft, TreeTy* oldTree, TreeTy* newRight) { + return createNode(newLeft, getValue(oldTree), newRight); + } + + void recoverNodes() { + for (unsigned i = 0, n = createdNodes.size(); i < n; ++i) { + TreeTy *N = createdNodes[i]; + if (N->isMutable() && N->refCount == 0) + N->destroy(); } - else return CreateNode(L, Value(OldTree), R); + createdNodes.clear(); } - - /// Balance - Used by Add_internal and Remove_internal to + + /// balanceTree - Used by add_internal and remove_internal to /// balance a newly created tree. - TreeTy* Balance(TreeTy* L, value_type_ref V, TreeTy* R) { - - unsigned hl = Height(L); - unsigned hr = Height(R); - + TreeTy* balanceTree(TreeTy* L, value_type_ref V, TreeTy* R) { + unsigned hl = getHeight(L); + unsigned hr = getHeight(R); + if (hl > hr + 2) { - assert (!isEmpty(L) && - "Left tree cannot be empty to have a height >= 2."); - - TreeTy* LL = Left(L); - TreeTy* LR = Right(L); - - if (Height(LL) >= Height(LR)) - return CreateNode(LL, L, CreateNode(LR,V,R)); - - assert (!isEmpty(LR) && - "LR cannot be empty because it has a height >= 1."); - - TreeTy* LRL = Left(LR); - TreeTy* LRR = Right(LR); - - return CreateNode(CreateNode(LL,L,LRL), LR, CreateNode(LRR,V,R)); + assert(!isEmpty(L) && "Left tree cannot be empty to have a height >= 2"); + + TreeTy *LL = getLeft(L); + TreeTy *LR = getRight(L); + + if (getHeight(LL) >= getHeight(LR)) + return createNode(LL, L, createNode(LR,V,R)); + + assert(!isEmpty(LR) && "LR cannot be empty because it has a height >= 1"); + + TreeTy *LRL = getLeft(LR); + TreeTy *LRR = getRight(LR); + + return createNode(createNode(LL,L,LRL), LR, createNode(LRR,V,R)); } - else if (hr > hl + 2) { - assert (!isEmpty(R) && - "Right tree cannot be empty to have a height >= 2."); - - TreeTy* RL = Left(R); - TreeTy* RR = Right(R); - - if (Height(RR) >= Height(RL)) - return CreateNode(CreateNode(L,V,RL), R, RR); - - assert (!isEmpty(RL) && - "RL cannot be empty because it has a height >= 1."); - - TreeTy* RLL = Left(RL); - TreeTy* RLR = Right(RL); - - return CreateNode(CreateNode(L,V,RLL), RL, CreateNode(RLR,R,RR)); + + if (hr > hl + 2) { + assert(!isEmpty(R) && "Right tree cannot be empty to have a height >= 2"); + + TreeTy *RL = getLeft(R); + TreeTy *RR = getRight(R); + + if (getHeight(RR) >= getHeight(RL)) + return createNode(createNode(L,V,RL), R, RR); + + assert(!isEmpty(RL) && "RL cannot be empty because it has a height >= 1"); + + TreeTy *RLL = getLeft(RL); + TreeTy *RLR = getRight(RL); + + return createNode(createNode(L,V,RLL), RL, createNode(RLR,R,RR)); } - else - return CreateNode(L,V,R); + + return createNode(L,V,R); } - - /// Add_internal - Creates a new tree that includes the specified + + /// add_internal - Creates a new tree that includes the specified /// data and the data from the original tree. If the original tree /// already contained the data item, the original tree is returned. - TreeTy* Add_internal(value_type_ref V, TreeTy* T) { + TreeTy* add_internal(value_type_ref V, TreeTy* T) { if (isEmpty(T)) - return CreateNode(T, V, T); - - assert (!T->isMutable()); - + return createNode(T, V, T); + assert(!T->isMutable()); + key_type_ref K = ImutInfo::KeyOfValue(V); - key_type_ref KCurrent = ImutInfo::KeyOfValue(Value(T)); - + key_type_ref KCurrent = ImutInfo::KeyOfValue(getValue(T)); + if (ImutInfo::isEqual(K,KCurrent)) - return CreateNode(Left(T), V, Right(T)); + return createNode(getLeft(T), V, getRight(T)); else if (ImutInfo::isLess(K,KCurrent)) - return Balance(Add_internal(V,Left(T)), Value(T), Right(T)); + return balanceTree(add_internal(V, getLeft(T)), getValue(T), getRight(T)); else - return Balance(Left(T), Value(T), Add_internal(V,Right(T))); + return balanceTree(getLeft(T), getValue(T), add_internal(V, getRight(T))); } - - /// Remove_interal - Creates a new tree that includes all the data + + /// remove_internal - Creates a new tree that includes all the data /// from the original tree except the specified data. If the /// specified data did not exist in the original tree, the original /// tree is returned. - TreeTy* Remove_internal(key_type_ref K, TreeTy* T) { + TreeTy* remove_internal(key_type_ref K, TreeTy* T) { if (isEmpty(T)) return T; - - assert (!T->isMutable()); - - key_type_ref KCurrent = ImutInfo::KeyOfValue(Value(T)); - - if (ImutInfo::isEqual(K,KCurrent)) - return CombineLeftRightTrees(Left(T),Right(T)); - else if (ImutInfo::isLess(K,KCurrent)) - return Balance(Remove_internal(K,Left(T)), Value(T), Right(T)); - else - return Balance(Left(T), Value(T), Remove_internal(K,Right(T))); - } - - TreeTy* CombineLeftRightTrees(TreeTy* L, TreeTy* R) { - if (isEmpty(L)) return R; - if (isEmpty(R)) return L; - - TreeTy* OldNode; - TreeTy* NewRight = RemoveMinBinding(R,OldNode); - return Balance(L,Value(OldNode),NewRight); - } - - TreeTy* RemoveMinBinding(TreeTy* T, TreeTy*& NodeRemoved) { - assert (!isEmpty(T)); - - if (isEmpty(Left(T))) { - NodeRemoved = T; - return Right(T); + + assert(!T->isMutable()); + + key_type_ref KCurrent = ImutInfo::KeyOfValue(getValue(T)); + + if (ImutInfo::isEqual(K,KCurrent)) { + return combineTrees(getLeft(T), getRight(T)); + } else if (ImutInfo::isLess(K,KCurrent)) { + return balanceTree(remove_internal(K, getLeft(T)), + getValue(T), getRight(T)); + } else { + return balanceTree(getLeft(T), getValue(T), + remove_internal(K, getRight(T))); } - - return Balance(RemoveMinBinding(Left(T),NodeRemoved),Value(T),Right(T)); - } - - /// MarkImmutable - Clears the mutable bits of a root and all of its + } + + TreeTy* combineTrees(TreeTy* L, TreeTy* R) { + if (isEmpty(L)) + return R; + if (isEmpty(R)) + return L; + TreeTy* OldNode; + TreeTy* newRight = removeMinBinding(R,OldNode); + return balanceTree(L, getValue(OldNode), newRight); + } + + TreeTy* removeMinBinding(TreeTy* T, TreeTy*& Noderemoved) { + assert(!isEmpty(T)); + if (isEmpty(getLeft(T))) { + Noderemoved = T; + return getRight(T); + } + return balanceTree(removeMinBinding(getLeft(T), Noderemoved), + getValue(T), getRight(T)); + } + + /// markImmutable - Clears the mutable bits of a root and all of its /// descendants. - void MarkImmutable(TreeTy* T) { + void markImmutable(TreeTy* T) { if (!T || !T->isMutable()) return; - - T->MarkImmutable(); - MarkImmutable(Left(T)); - MarkImmutable(Right(T)); + T->markImmutable(); + markImmutable(getLeft(T)); + markImmutable(getRight(T)); + } + +public: + TreeTy *getCanonicalTree(TreeTy *TNew) { + if (!TNew) + return nullptr; + + if (TNew->IsCanonicalized) + return TNew; + + // Search the hashtable for another tree with the same digest, and + // if find a collision compare those trees by their contents. + unsigned digest = TNew->computeDigest(); + TreeTy *&entry = Cache[maskCacheIndex(digest)]; + do { + if (!entry) + break; + for (TreeTy *T = entry ; T != nullptr; T = T->next) { + // Compare the Contents('T') with Contents('TNew') + typename TreeTy::iterator TI = T->begin(), TE = T->end(); + if (!compareTreeWithSection(TNew, TI, TE)) + continue; + if (TI != TE) + continue; // T has more contents than TNew. + // Trees did match! Return 'T'. + if (TNew->refCount == 0) + TNew->destroy(); + return T; + } + entry->prev = TNew; + TNew->next = entry; + } + while (false); + + entry = TNew; + TNew->IsCanonicalized = true; + return TNew; } }; - - -//===----------------------------------------------------------------------===// + +//===----------------------------------------------------------------------===// // Immutable AVL-Tree Iterators. -//===----------------------------------------------------------------------===// +//===----------------------------------------------------------------------===// template -class ImutAVLTreeGenericIterator { +class ImutAVLTreeGenericIterator + : public std::iterator> { SmallVector stack; public: - enum VisitFlag { VisitedNone=0x0, VisitedLeft=0x1, VisitedRight=0x3, + enum VisitFlag { VisitedNone=0x0, VisitedLeft=0x1, VisitedRight=0x3, Flags=0x3 }; - - typedef ImutAVLTree TreeTy; - typedef ImutAVLTreeGenericIterator _Self; - inline ImutAVLTreeGenericIterator() {} - inline ImutAVLTreeGenericIterator(const TreeTy* Root) { + typedef ImutAVLTree TreeTy; + + ImutAVLTreeGenericIterator() {} + ImutAVLTreeGenericIterator(const TreeTy *Root) { if (Root) stack.push_back(reinterpret_cast(Root)); - } - - TreeTy* operator*() const { - assert (!stack.empty()); - return reinterpret_cast(stack.back() & ~Flags); - } - - uintptr_t getVisitState() { - assert (!stack.empty()); + } + + TreeTy &operator*() const { + assert(!stack.empty()); + return *reinterpret_cast(stack.back() & ~Flags); + } + TreeTy *operator->() const { return &*this; } + + uintptr_t getVisitState() const { + assert(!stack.empty()); return stack.back() & Flags; } - - - bool AtEnd() const { return stack.empty(); } - bool AtBeginning() const { + + bool atEnd() const { return stack.empty(); } + + bool atBeginning() const { return stack.size() == 1 && getVisitState() == VisitedNone; } - - void SkipToParent() { - assert (!stack.empty()); + + void skipToParent() { + assert(!stack.empty()); stack.pop_back(); - if (stack.empty()) return; - switch (getVisitState()) { case VisitedNone: stack.back() |= VisitedLeft; @@ -568,143 +691,142 @@ public: stack.back() |= VisitedRight; break; default: - assert (false && "Unreachable."); + llvm_unreachable("Unreachable."); } } - - inline bool operator==(const _Self& x) const { - if (stack.size() != x.stack.size()) - return false; - - for (unsigned i = 0 ; i < stack.size(); i++) - if (stack[i] != x.stack[i]) - return false; - - return true; + + bool operator==(const ImutAVLTreeGenericIterator &x) const { + return stack == x.stack; } - - inline bool operator!=(const _Self& x) const { return !operator==(x); } - - _Self& operator++() { - assert (!stack.empty()); - + + bool operator!=(const ImutAVLTreeGenericIterator &x) const { + return !(*this == x); + } + + ImutAVLTreeGenericIterator &operator++() { + assert(!stack.empty()); TreeTy* Current = reinterpret_cast(stack.back() & ~Flags); - assert (Current); - + assert(Current); switch (getVisitState()) { case VisitedNone: if (TreeTy* L = Current->getLeft()) stack.push_back(reinterpret_cast(L)); else stack.back() |= VisitedLeft; - break; - case VisitedLeft: if (TreeTy* R = Current->getRight()) stack.push_back(reinterpret_cast(R)); else stack.back() |= VisitedRight; - break; - case VisitedRight: - SkipToParent(); + skipToParent(); break; - default: - assert (false && "Unreachable."); + llvm_unreachable("Unreachable."); } - return *this; } - - _Self& operator--() { - assert (!stack.empty()); - + + ImutAVLTreeGenericIterator &operator--() { + assert(!stack.empty()); TreeTy* Current = reinterpret_cast(stack.back() & ~Flags); - assert (Current); - + assert(Current); switch (getVisitState()) { case VisitedNone: stack.pop_back(); break; - - case VisitedLeft: + case VisitedLeft: stack.back() &= ~Flags; // Set state to "VisitedNone." - if (TreeTy* L = Current->getLeft()) stack.push_back(reinterpret_cast(L) | VisitedRight); - break; - - case VisitedRight: + case VisitedRight: stack.back() &= ~Flags; stack.back() |= VisitedLeft; - if (TreeTy* R = Current->getRight()) stack.push_back(reinterpret_cast(R) | VisitedRight); - break; - default: - assert (false && "Unreachable."); + llvm_unreachable("Unreachable."); } - return *this; } }; - + template -class ImutAVLTreeInOrderIterator { +class ImutAVLTreeInOrderIterator + : public std::iterator> { typedef ImutAVLTreeGenericIterator InternalIteratorTy; InternalIteratorTy InternalItr; public: typedef ImutAVLTree TreeTy; - typedef ImutAVLTreeInOrderIterator _Self; - ImutAVLTreeInOrderIterator(const TreeTy* Root) : InternalItr(Root) { - if (Root) operator++(); // Advance to first element. + ImutAVLTreeInOrderIterator(const TreeTy* Root) : InternalItr(Root) { + if (Root) + ++*this; // Advance to first element. } - + ImutAVLTreeInOrderIterator() : InternalItr() {} - inline bool operator==(const _Self& x) const { + bool operator==(const ImutAVLTreeInOrderIterator &x) const { return InternalItr == x.InternalItr; } - - inline bool operator!=(const _Self& x) const { return !operator==(x); } - - inline TreeTy* operator*() const { return *InternalItr; } - inline TreeTy* operator->() const { return *InternalItr; } - - inline _Self& operator++() { + + bool operator!=(const ImutAVLTreeInOrderIterator &x) const { + return !(*this == x); + } + + TreeTy &operator*() const { return *InternalItr; } + TreeTy *operator->() const { return &*InternalItr; } + + ImutAVLTreeInOrderIterator &operator++() { do ++InternalItr; - while (!InternalItr.AtEnd() && + while (!InternalItr.atEnd() && InternalItr.getVisitState() != InternalIteratorTy::VisitedLeft); return *this; } - - inline _Self& operator--() { + + ImutAVLTreeInOrderIterator &operator--() { do --InternalItr; - while (!InternalItr.AtBeginning() && + while (!InternalItr.atBeginning() && InternalItr.getVisitState() != InternalIteratorTy::VisitedLeft); - + return *this; } - - inline void SkipSubTree() { - InternalItr.SkipToParent(); - - while (!InternalItr.AtEnd() && + + void skipSubTree() { + InternalItr.skipToParent(); + + while (!InternalItr.atEnd() && InternalItr.getVisitState() != InternalIteratorTy::VisitedLeft) - ++InternalItr; + ++InternalItr; + } +}; + +/// Generic iterator that wraps a T::TreeTy::iterator and exposes +/// iterator::getValue() on dereference. +template +struct ImutAVLValueIterator + : iterator_adaptor_base< + ImutAVLValueIterator, typename T::TreeTy::iterator, + typename std::iterator_traits< + typename T::TreeTy::iterator>::iterator_category, + const typename T::value_type> { + ImutAVLValueIterator() = default; + explicit ImutAVLValueIterator(typename T::TreeTy *Tree) + : ImutAVLValueIterator::iterator_adaptor_base(Tree) {} + + typename ImutAVLValueIterator::reference operator*() const { + return this->I->getValue(); } }; - -//===----------------------------------------------------------------------===// + +//===----------------------------------------------------------------------===// // Trait classes for Profile information. //===----------------------------------------------------------------------===// @@ -715,21 +837,21 @@ template struct ImutProfileInfo { typedef const T value_type; typedef const T& value_type_ref; - - static inline void Profile(FoldingSetNodeID& ID, value_type_ref X) { - X.Profile(ID); - } + + static void Profile(FoldingSetNodeID &ID, value_type_ref X) { + FoldingSetTrait::Profile(X,ID); + } }; /// Profile traits for integers. template -struct ImutProfileInteger { +struct ImutProfileInteger { typedef const T value_type; typedef const T& value_type_ref; - - static inline void Profile(FoldingSetNodeID& ID, value_type_ref X) { + + static void Profile(FoldingSetNodeID &ID, value_type_ref X) { ID.AddInteger(X); - } + } }; #define PROFILE_INTEGER_INFO(X)\ @@ -748,19 +870,31 @@ PROFILE_INTEGER_INFO(unsigned long long) #undef PROFILE_INTEGER_INFO +/// Profile traits for booleans. +template <> +struct ImutProfileInfo { + typedef const bool value_type; + typedef const bool& value_type_ref; + + static void Profile(FoldingSetNodeID &ID, value_type_ref X) { + ID.AddBoolean(X); + } +}; + + /// Generic profile trait for pointer types. We treat pointers as /// references to unique objects. template struct ImutProfileInfo { typedef const T* value_type; typedef value_type value_type_ref; - - static inline void Profile(FoldingSetNodeID &ID, value_type_ref X) { + + static void Profile(FoldingSetNodeID &ID, value_type_ref X) { ID.AddPointer(X); } }; -//===----------------------------------------------------------------------===// +//===----------------------------------------------------------------------===// // Trait classes that contain element comparison operators and type // definitions used by ImutAVLTree, ImmutableSet, and ImmutableMap. These // inherit from the profile traits (ImutProfileInfo) to include operations @@ -779,19 +913,19 @@ struct ImutContainerInfo : public ImutProfileInfo { typedef value_type_ref key_type_ref; typedef bool data_type; typedef bool data_type_ref; - - static inline key_type_ref KeyOfValue(value_type_ref D) { return D; } - static inline data_type_ref DataOfValue(value_type_ref) { return true; } - - static inline bool isEqual(key_type_ref LHS, key_type_ref RHS) { + + static key_type_ref KeyOfValue(value_type_ref D) { return D; } + static data_type_ref DataOfValue(value_type_ref) { return true; } + + static bool isEqual(key_type_ref LHS, key_type_ref RHS) { return std::equal_to()(LHS,RHS); } - - static inline bool isLess(key_type_ref LHS, key_type_ref RHS) { + + static bool isLess(key_type_ref LHS, key_type_ref RHS) { return std::less()(LHS,RHS); } - - static inline bool isDataEqual(data_type_ref,data_type_ref) { return true; } + + static bool isDataEqual(data_type_ref, data_type_ref) { return true; } }; /// ImutContainerInfo - Specialization for pointer values to treat pointers @@ -805,22 +939,18 @@ struct ImutContainerInfo : public ImutProfileInfo { typedef value_type_ref key_type_ref; typedef bool data_type; typedef bool data_type_ref; - - static inline key_type_ref KeyOfValue(value_type_ref D) { return D; } - static inline data_type_ref DataOfValue(value_type_ref) { return true; } - - static inline bool isEqual(key_type_ref LHS, key_type_ref RHS) { - return LHS == RHS; - } - - static inline bool isLess(key_type_ref LHS, key_type_ref RHS) { - return LHS < RHS; - } - - static inline bool isDataEqual(data_type_ref,data_type_ref) { return true; } + + static key_type_ref KeyOfValue(value_type_ref D) { return D; } + static data_type_ref DataOfValue(value_type_ref) { return true; } + + static bool isEqual(key_type_ref LHS, key_type_ref RHS) { return LHS == RHS; } + + static bool isLess(key_type_ref LHS, key_type_ref RHS) { return LHS < RHS; } + + static bool isDataEqual(data_type_ref, data_type_ref) { return true; } }; -//===----------------------------------------------------------------------===// +//===----------------------------------------------------------------------===// // Immutable Set //===----------------------------------------------------------------------===// @@ -829,106 +959,258 @@ class ImmutableSet { public: typedef typename ValInfo::value_type value_type; typedef typename ValInfo::value_type_ref value_type_ref; - -private: typedef ImutAVLTree TreeTy; - TreeTy* Root; - - ImmutableSet(TreeTy* R) : Root(R) {} - + +private: + TreeTy *Root; + public: - + /// Constructs a set from a pointer to a tree root. In general one + /// should use a Factory object to create sets instead of directly + /// invoking the constructor, but there are cases where make this + /// constructor public is useful. + explicit ImmutableSet(TreeTy* R) : Root(R) { + if (Root) { Root->retain(); } + } + ImmutableSet(const ImmutableSet &X) : Root(X.Root) { + if (Root) { Root->retain(); } + } + ImmutableSet &operator=(const ImmutableSet &X) { + if (Root != X.Root) { + if (X.Root) { X.Root->retain(); } + if (Root) { Root->release(); } + Root = X.Root; + } + return *this; + } + ~ImmutableSet() { + if (Root) { Root->release(); } + } + class Factory { typename TreeTy::Factory F; - + const bool Canonicalize; + public: - Factory() {} - - /// GetEmptySet - Returns an immutable set that contains no elements. - ImmutableSet GetEmptySet() { return ImmutableSet(F.GetEmptyTree()); } - - /// Add - Creates a new immutable set that contains all of the values + Factory(bool canonicalize = true) + : Canonicalize(canonicalize) {} + + Factory(BumpPtrAllocator& Alloc, bool canonicalize = true) + : F(Alloc), Canonicalize(canonicalize) {} + + /// getEmptySet - Returns an immutable set that contains no elements. + ImmutableSet getEmptySet() { + return ImmutableSet(F.getEmptyTree()); + } + + /// add - Creates a new immutable set that contains all of the values /// of the original set with the addition of the specified value. If /// the original set already included the value, then the original set is /// returned and no memory is allocated. The time and space complexity /// of this operation is logarithmic in the size of the original set. /// The memory allocated to represent the set is released when the /// factory object that created the set is destroyed. - ImmutableSet Add(ImmutableSet Old, value_type_ref V) { - return ImmutableSet(F.Add(Old.Root,V)); + ImmutableSet add(ImmutableSet Old, value_type_ref V) { + TreeTy *NewT = F.add(Old.Root, V); + return ImmutableSet(Canonicalize ? F.getCanonicalTree(NewT) : NewT); } - - /// Remove - Creates a new immutable set that contains all of the values + + /// remove - Creates a new immutable set that contains all of the values /// of the original set with the exception of the specified value. If /// the original set did not contain the value, the original set is /// returned and no memory is allocated. The time and space complexity /// of this operation is logarithmic in the size of the original set. /// The memory allocated to represent the set is released when the /// factory object that created the set is destroyed. - ImmutableSet Remove(ImmutableSet Old, value_type_ref V) { - return ImmutableSet(F.Remove(Old.Root,V)); + ImmutableSet remove(ImmutableSet Old, value_type_ref V) { + TreeTy *NewT = F.remove(Old.Root, V); + return ImmutableSet(Canonicalize ? F.getCanonicalTree(NewT) : NewT); } - + BumpPtrAllocator& getAllocator() { return F.getAllocator(); } + typename TreeTy::Factory *getTreeFactory() const { + return const_cast(&F); + } + private: - Factory(const Factory& RHS) {}; - void operator=(const Factory& RHS) {}; + Factory(const Factory& RHS) = delete; + void operator=(const Factory& RHS) = delete; }; - - friend class Factory; - /// contains - Returns true if the set contains the specified value. - bool contains(const value_type_ref V) const { + friend class Factory; + + /// Returns true if the set contains the specified value. + bool contains(value_type_ref V) const { return Root ? Root->contains(V) : false; } - - bool operator==(ImmutableSet RHS) const { + + bool operator==(const ImmutableSet &RHS) const { return Root && RHS.Root ? Root->isEqual(*RHS.Root) : Root == RHS.Root; } - - bool operator!=(ImmutableSet RHS) const { + + bool operator!=(const ImmutableSet &RHS) const { return Root && RHS.Root ? Root->isNotEqual(*RHS.Root) : Root != RHS.Root; } - + + TreeTy *getRoot() { + if (Root) { Root->retain(); } + return Root; + } + + TreeTy *getRootWithoutRetain() const { + return Root; + } + /// isEmpty - Return true if the set contains no elements. bool isEmpty() const { return !Root; } - + + /// isSingleton - Return true if the set contains exactly one element. + /// This method runs in constant time. + bool isSingleton() const { return getHeight() == 1; } + template void foreach(Callback& C) { if (Root) Root->foreach(C); } - + template void foreach() { if (Root) { Callback C; Root->foreach(C); } } - - //===--------------------------------------------------===// + + //===--------------------------------------------------===// // Iterators. - //===--------------------------------------------------===// - - class iterator { - typename TreeTy::iterator itr; - - iterator() {} - iterator(TreeTy* t) : itr(t) {} - friend class ImmutableSet; - public: - inline value_type_ref operator*() const { return itr->getValue(); } - inline iterator& operator++() { ++itr; return *this; } - inline iterator operator++(int) { iterator tmp(*this); ++itr; return tmp; } - inline iterator& operator--() { --itr; return *this; } - inline iterator operator--(int) { iterator tmp(*this); --itr; return tmp; } - inline bool operator==(const iterator& RHS) const { return RHS.itr == itr; } - inline bool operator!=(const iterator& RHS) const { return RHS.itr != itr; } - }; - + //===--------------------------------------------------===// + + typedef ImutAVLValueIterator iterator; + iterator begin() const { return iterator(Root); } - iterator end() const { return iterator(); } - - //===--------------------------------------------------===// + iterator end() const { return iterator(); } + + //===--------------------------------------------------===// + // Utility methods. + //===--------------------------------------------------===// + + unsigned getHeight() const { return Root ? Root->getHeight() : 0; } + + static void Profile(FoldingSetNodeID &ID, const ImmutableSet &S) { + ID.AddPointer(S.Root); + } + + void Profile(FoldingSetNodeID &ID) const { return Profile(ID, *this); } + + //===--------------------------------------------------===// // For testing. - //===--------------------------------------------------===// - - void verify() const { if (Root) Root->verify(); } + //===--------------------------------------------------===// + + void validateTree() const { if (Root) Root->validateTree(); } +}; + +// NOTE: This may some day replace the current ImmutableSet. +template > +class ImmutableSetRef { +public: + typedef typename ValInfo::value_type value_type; + typedef typename ValInfo::value_type_ref value_type_ref; + typedef ImutAVLTree TreeTy; + typedef typename TreeTy::Factory FactoryTy; + +private: + TreeTy *Root; + FactoryTy *Factory; + +public: + /// Constructs a set from a pointer to a tree root. In general one + /// should use a Factory object to create sets instead of directly + /// invoking the constructor, but there are cases where make this + /// constructor public is useful. + explicit ImmutableSetRef(TreeTy* R, FactoryTy *F) + : Root(R), + Factory(F) { + if (Root) { Root->retain(); } + } + ImmutableSetRef(const ImmutableSetRef &X) + : Root(X.Root), + Factory(X.Factory) { + if (Root) { Root->retain(); } + } + ImmutableSetRef &operator=(const ImmutableSetRef &X) { + if (Root != X.Root) { + if (X.Root) { X.Root->retain(); } + if (Root) { Root->release(); } + Root = X.Root; + Factory = X.Factory; + } + return *this; + } + ~ImmutableSetRef() { + if (Root) { Root->release(); } + } + + static ImmutableSetRef getEmptySet(FactoryTy *F) { + return ImmutableSetRef(0, F); + } + + ImmutableSetRef add(value_type_ref V) { + return ImmutableSetRef(Factory->add(Root, V), Factory); + } + + ImmutableSetRef remove(value_type_ref V) { + return ImmutableSetRef(Factory->remove(Root, V), Factory); + } + + /// Returns true if the set contains the specified value. + bool contains(value_type_ref V) const { + return Root ? Root->contains(V) : false; + } + + ImmutableSet asImmutableSet(bool canonicalize = true) const { + return ImmutableSet(canonicalize ? + Factory->getCanonicalTree(Root) : Root); + } + + TreeTy *getRootWithoutRetain() const { + return Root; + } + + bool operator==(const ImmutableSetRef &RHS) const { + return Root && RHS.Root ? Root->isEqual(*RHS.Root) : Root == RHS.Root; + } + + bool operator!=(const ImmutableSetRef &RHS) const { + return Root && RHS.Root ? Root->isNotEqual(*RHS.Root) : Root != RHS.Root; + } + + /// isEmpty - Return true if the set contains no elements. + bool isEmpty() const { return !Root; } + + /// isSingleton - Return true if the set contains exactly one element. + /// This method runs in constant time. + bool isSingleton() const { return getHeight() == 1; } + + //===--------------------------------------------------===// + // Iterators. + //===--------------------------------------------------===// + + typedef ImutAVLValueIterator iterator; + + iterator begin() const { return iterator(Root); } + iterator end() const { return iterator(); } + + //===--------------------------------------------------===// + // Utility methods. + //===--------------------------------------------------===// + unsigned getHeight() const { return Root ? Root->getHeight() : 0; } + + static void Profile(FoldingSetNodeID &ID, const ImmutableSetRef &S) { + ID.AddPointer(S.Root); + } + + void Profile(FoldingSetNodeID &ID) const { return Profile(ID, *this); } + + //===--------------------------------------------------===// + // For testing. + //===--------------------------------------------------===// + + void validateTree() const { if (Root) Root->validateTree(); } }; } // end namespace llvm