X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=include%2Fllvm%2FADT%2FSmallPtrSet.h;h=a189de2c2279de206e1b01d88f0099b0ad8d9103;hb=747972914ae73379fd837e5a30cea229be792e34;hp=d617d6b3b0b5ad8278d2a8283353cc2bac0cbfba;hpb=18b69106b7a66ac6abde37d1be6d0d952796ed04;p=oota-llvm.git

diff --git a/include/llvm/ADT/SmallPtrSet.h b/include/llvm/ADT/SmallPtrSet.h
index d617d6b3b0b..a189de2c227 100644
--- a/include/llvm/ADT/SmallPtrSet.h
+++ b/include/llvm/ADT/SmallPtrSet.h
@@ -2,8 +2,8 @@
 //
 //                     The LLVM Compiler Infrastructure
 //
-// This file was developed by Chris Lattner and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
@@ -17,9 +17,13 @@
 
 #include <cassert>
 #include <cstring>
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/PointerLikeTypeTraits.h"
 
 namespace llvm {
 
+class SmallPtrSetIteratorImpl;
+
 /// SmallPtrSetImpl - This is the common code shared among all the
 /// SmallPtrSet<>'s, which is almost everything.  SmallPtrSet has two modes, one
 /// for small and one for large sets.
@@ -39,20 +43,24 @@ namespace llvm {
 /// more.  When this happens, the table is doubled in size.
 ///
 class SmallPtrSetImpl {
+  friend class SmallPtrSetIteratorImpl;
 protected:
   /// CurArray - This is the current set of buckets.  If it points to
   /// SmallArray, then the set is in 'small mode'.
-  void **CurArray;
+  const void **CurArray;
   /// CurArraySize - The allocated size of CurArray, always a power of two.
   /// Note that CurArray points to an array that has CurArraySize+1 elements in
   /// it, so that the end iterator actually points to valid memory.
   unsigned CurArraySize;
-  
+
   // If small, this is # elts allocated consequtively
   unsigned NumElements;
-  void *SmallArray[1];  // Must be last ivar.
-public:
-  SmallPtrSetImpl(unsigned SmallSize) {
+  unsigned NumTombstones;
+  const void *SmallArray[1];  // Must be last ivar.
+
+  // Helper to copy construct a SmallPtrSet.
+  SmallPtrSetImpl(const SmallPtrSetImpl& that);
+  explicit SmallPtrSetImpl(unsigned SmallSize) {
     assert(SmallSize && (SmallSize & (SmallSize-1)) == 0 &&
            "Initial size must be a power of two!");
     CurArray = &SmallArray[0];
@@ -62,71 +70,91 @@ public:
     CurArray[SmallSize] = 0;
     clear();
   }
-  ~SmallPtrSetImpl() {
-    if (!isSmall())
-      delete[] CurArray;
+  ~SmallPtrSetImpl();
+
+public:
+  bool empty() const { return size() == 0; }
+  unsigned size() const { return NumElements; }
+
+  void clear() {
+    // If the capacity of the array is huge, and the # elements used is small,
+    // shrink the array.
+    if (!isSmall() && NumElements*4 < CurArraySize && CurArraySize > 32)
+      return shrink_and_clear();
+
+    // Fill the array with empty markers.
+    memset(CurArray, -1, CurArraySize*sizeof(void*));
+    NumElements = 0;
+    NumTombstones = 0;
   }
-  
-  bool isSmall() const { return CurArray == &SmallArray[0]; }
 
+protected:
   static void *getTombstoneMarker() { return reinterpret_cast<void*>(-2); }
   static void *getEmptyMarker() {
     // Note that -1 is chosen to make clear() efficiently implementable with
     // memset and because it's not a valid pointer value.
     return reinterpret_cast<void*>(-1);
   }
-  
-  void clear() {
-    // Fill the array with empty markers.
-    memset(CurArray, -1, CurArraySize*sizeof(void*));
-    NumElements = 0;
-  }
-  
-  /// insert - This returns true if the pointer was new to the set, false if it
-  /// was already in the set.
-  bool insert(void *Ptr);
-  
-  bool count(void *Ptr) const {
+
+  /// insert_imp - This returns true if the pointer was new to the set, false if
+  /// it was already in the set.  This is hidden from the client so that the
+  /// derived class can check that the right type of pointer is passed in.
+  bool insert_imp(const void * Ptr);
+
+  /// erase_imp - If the set contains the specified pointer, remove it and
+  /// return true, otherwise return false.  This is hidden from the client so
+  /// that the derived class can check that the right type of pointer is passed
+  /// in.
+  bool erase_imp(const void * Ptr);
+
+  bool count_imp(const void * Ptr) const {
     if (isSmall()) {
       // Linear search for the item.
-      for (void *const *APtr = SmallArray, *const *E = SmallArray+NumElements;
-           APtr != E; ++APtr)
+      for (const void *const *APtr = SmallArray,
+                      *const *E = SmallArray+NumElements; APtr != E; ++APtr)
         if (*APtr == Ptr)
           return true;
       return false;
     }
-    
+
     // Big set case.
     return *FindBucketFor(Ptr) == Ptr;
   }
-  
+
 private:
-  unsigned Hash(void *Ptr) const {
-    return ((uintptr_t)Ptr >> 4) & (CurArraySize-1);
+  bool isSmall() const { return CurArray == &SmallArray[0]; }
+
+  unsigned Hash(const void *Ptr) const {
+    return static_cast<unsigned>(((uintptr_t)Ptr >> 4) & (CurArraySize-1));
   }
-  void * const *FindBucketFor(void *Ptr) const;
-  
+  const void * const *FindBucketFor(const void *Ptr) const;
+  void shrink_and_clear();
+
   /// Grow - Allocate a larger backing store for the buckets and move it over.
   void Grow();
+
+  void operator=(const SmallPtrSetImpl &RHS);  // DO NOT IMPLEMENT.
+protected:
+  void CopyFrom(const SmallPtrSetImpl &RHS);
 };
 
 /// SmallPtrSetIteratorImpl - This is the common base class shared between all
 /// instances of SmallPtrSetIterator.
 class SmallPtrSetIteratorImpl {
 protected:
-  void *const *Bucket;
+  const void *const *Bucket;
 public:
-  SmallPtrSetIteratorImpl(void *const *BP) : Bucket(BP) {
+  explicit SmallPtrSetIteratorImpl(const void *const *BP) : Bucket(BP) {
     AdvanceIfNotValid();
   }
-  
+
   bool operator==(const SmallPtrSetIteratorImpl &RHS) const {
     return Bucket == RHS.Bucket;
   }
   bool operator!=(const SmallPtrSetIteratorImpl &RHS) const {
     return Bucket != RHS.Bucket;
   }
-  
+
 protected:
   /// AdvanceIfNotValid - If the current bucket isn't valid, advance to a bucket
   /// that is.   This is guaranteed to stop because the end() bucket is marked
@@ -141,34 +169,97 @@ protected:
 /// SmallPtrSetIterator - This implements a const_iterator for SmallPtrSet.
 template<typename PtrTy>
 class SmallPtrSetIterator : public SmallPtrSetIteratorImpl {
+  typedef PointerLikeTypeTraits<PtrTy> PtrTraits;
 public:
-  SmallPtrSetIterator(void *const *BP) : SmallPtrSetIteratorImpl(BP) {}
+  explicit SmallPtrSetIterator(const void *const *BP)
+    : SmallPtrSetIteratorImpl(BP) {}
 
   // Most methods provided by baseclass.
-  
-  PtrTy operator*() const {
-    return static_cast<PtrTy>(*Bucket);
+
+  const PtrTy operator*() const {
+    return PtrTraits::getFromVoidPointer(const_cast<void*>(*Bucket));
   }
-  
+
   inline SmallPtrSetIterator& operator++() {          // Preincrement
     ++Bucket;
     AdvanceIfNotValid();
     return *this;
   }
-  
+
   SmallPtrSetIterator operator++(int) {        // Postincrement
     SmallPtrSetIterator tmp = *this; ++*this; return tmp;
   }
 };
 
+/// NextPowerOfTwo - This is a helper template that rounds N up to the next
+/// power of two.
+template<unsigned N>
+struct NextPowerOfTwo;
+
+/// NextPowerOfTwoH - If N is not a power of two, increase it.  This is a helper
+/// template used to implement NextPowerOfTwo.
+template<unsigned N, bool isPowerTwo>
+struct NextPowerOfTwoH {
+  enum { Val = N };
+};
+template<unsigned N>
+struct NextPowerOfTwoH<N, false> {
+  enum {
+    // We could just use NextVal = N+1, but this converges faster.  N|(N-1) sets
+    // the right-most zero bits to one all at once, e.g. 0b0011000 -> 0b0011111.
+    Val = NextPowerOfTwo<(N|(N-1)) + 1>::Val
+  };
+};
+
+template<unsigned N>
+struct NextPowerOfTwo {
+  enum { Val = NextPowerOfTwoH<N, (N&(N-1)) == 0>::Val };
+};
+  
 
-/// SmallPtrSet - This class implements 
+/// SmallPtrSet - This class implements a set which is optimizer for holding
+/// SmallSize or less elements.  This internally rounds up SmallSize to the next
+/// power of two if it is not already a power of two.  See the comments above
+/// SmallPtrSetImpl for details of the algorithm.
 template<class PtrType, unsigned SmallSize>
 class SmallPtrSet : public SmallPtrSetImpl {
-  void *SmallArray[SmallSize];
+  // Make sure that SmallSize is a power of two, round up if not.
+  enum { SmallSizePowTwo = NextPowerOfTwo<SmallSize>::Val };
+  void *SmallArray[SmallSizePowTwo];
+  typedef PointerLikeTypeTraits<PtrType> PtrTraits;
 public:
-  SmallPtrSet() : SmallPtrSetImpl(SmallSize) {}
-  
+  SmallPtrSet() : SmallPtrSetImpl(NextPowerOfTwo<SmallSizePowTwo>::Val) {}
+  SmallPtrSet(const SmallPtrSet &that) : SmallPtrSetImpl(that) {}
+
+  template<typename It>
+  SmallPtrSet(It I, It E)
+    : SmallPtrSetImpl(NextPowerOfTwo<SmallSizePowTwo>::Val) {
+    insert(I, E);
+  }
+
+  /// insert - This returns true if the pointer was new to the set, false if it
+  /// was already in the set.
+  bool insert(PtrType Ptr) {
+    return insert_imp(PtrTraits::getAsVoidPointer(Ptr));
+  }
+
+  /// erase - If the set contains the specified pointer, remove it and return
+  /// true, otherwise return false.
+  bool erase(PtrType Ptr) {
+    return erase_imp(PtrTraits::getAsVoidPointer(Ptr));
+  }
+
+  /// count - Return true if the specified pointer is in the set.
+  bool count(PtrType Ptr) const {
+    return count_imp(PtrTraits::getAsVoidPointer(Ptr));
+  }
+
+  template <typename IterT>
+  void insert(IterT I, IterT E) {
+    for (; I != E; ++I)
+      insert(*I);
+  }
+
   typedef SmallPtrSetIterator<PtrType> iterator;
   typedef SmallPtrSetIterator<PtrType> const_iterator;
   inline iterator begin() const {
@@ -177,6 +268,15 @@ public:
   inline iterator end() const {
     return iterator(CurArray+CurArraySize);
   }
+
+  // Allow assignment from any smallptrset with the same element type even if it
+  // doesn't have the same smallsize.
+  const SmallPtrSet<PtrType, SmallSize>&
+  operator=(const SmallPtrSet<PtrType, SmallSize> &RHS) {
+    CopyFrom(RHS);
+    return *this;
+  }
+
 };
 
 }