SmallVector and SmallPtrSet allocations now power-of-two aligned.

[oota-llvm.git] / include / llvm / ADT / SmallPtrSet.h

diff --git a/include/llvm/ADT/SmallPtrSet.h b/include/llvm/ADT/SmallPtrSet.h
index ff32ba87a264544c1d332d6fe7235f590d64689c..8c7304197f34f3cd183a016d4d83d2e01909a859 100644 (file)
--- a/include/llvm/ADT/SmallPtrSet.h
+++ b/include/llvm/ADT/SmallPtrSet.h
@@ -15,12 +15,13 @@
 #ifndef LLVM_ADT_SMALLPTRSET_H
 #define LLVM_ADT_SMALLPTRSET_H
 
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/DataTypes.h"
+#include "llvm/Support/PointerLikeTypeTraits.h"
 #include <cassert>
 #include <cstddef>
 #include <cstring>
 #include <iterator>
-#include "llvm/Support/DataTypes.h"
-#include "llvm/Support/PointerLikeTypeTraits.h"
 
 namespace llvm {
 
@@ -53,8 +54,6 @@ protected:
   /// then the set is in 'small mode'.
   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 consecutively
@@ -67,9 +66,6 @@ protected:
     SmallArray(SmallStorage), CurArray(SmallStorage), CurArraySize(SmallSize) {
     assert(SmallSize && (SmallSize & (SmallSize-1)) == 0 &&
            "Initial size must be a power of two!");
-    // The end pointer, always valid, is set to a valid element to help the
-    // iterator.
-    CurArray[SmallSize] = 0;
     clear();
   }
   ~SmallPtrSetImpl();
@@ -126,17 +122,18 @@ protected:
 private:
   bool isSmall() const { return CurArray == SmallArray; }
 
-  unsigned Hash(const void *Ptr) const {
-    return static_cast<unsigned>(((uintptr_t)Ptr >> 4) & (CurArraySize-1));
-  }
   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 Grow(unsigned NewSize);
 
-  void operator=(const SmallPtrSetImpl &RHS);  // DO NOT IMPLEMENT.
+  void operator=(const SmallPtrSetImpl &RHS) LLVM_DELETED_FUNCTION;
 protected:
+  /// swap - Swaps the elements of two sets.
+  /// Note: This method assumes that both sets have the same small size.
+  void swap(SmallPtrSetImpl &RHS);
+
   void CopyFrom(const SmallPtrSetImpl &RHS);
 };
 
@@ -145,9 +142,11 @@ protected:
 class SmallPtrSetIteratorImpl {
 protected:
   const void *const *Bucket;
+  const void *const *End;
 public:
-  explicit SmallPtrSetIteratorImpl(const void *const *BP) : Bucket(BP) {
-    AdvanceIfNotValid();
+  explicit SmallPtrSetIteratorImpl(const void *const *BP, const void*const *E)
+    : Bucket(BP), End(E) {
+      AdvanceIfNotValid();
   }
 
   bool operator==(const SmallPtrSetIteratorImpl &RHS) const {
@@ -162,8 +161,10 @@ protected:
   /// that is.   This is guaranteed to stop because the end() bucket is marked
   /// valid.
   void AdvanceIfNotValid() {
-    while (*Bucket == SmallPtrSetImpl::getEmptyMarker() ||
-           *Bucket == SmallPtrSetImpl::getTombstoneMarker())
+    assert(Bucket <= End);
+    while (Bucket != End &&
+           (*Bucket == SmallPtrSetImpl::getEmptyMarker() ||
+            *Bucket == SmallPtrSetImpl::getTombstoneMarker()))
       ++Bucket;
   }
 };
@@ -180,12 +181,13 @@ public:
   typedef std::ptrdiff_t            difference_type;
   typedef std::forward_iterator_tag iterator_category;
   
-  explicit SmallPtrSetIterator(const void *const *BP)
-    : SmallPtrSetIteratorImpl(BP) {}
+  explicit SmallPtrSetIterator(const void *const *BP, const void *const *E)
+    : SmallPtrSetIteratorImpl(BP, E) {}
 
   // Most methods provided by baseclass.
 
   const PtrTy operator*() const {
+    assert(Bucket < End);
     return PtrTraits::getFromVoidPointer(const_cast<void*>(*Bucket));
   }
 
@@ -234,9 +236,8 @@ template<class PtrType, unsigned SmallSize>
 class SmallPtrSet : public SmallPtrSetImpl {
   // Make sure that SmallSize is a power of two, round up if not.
   enum { SmallSizePowTwo = RoundUpToPowerOfTwo<SmallSize>::Val };
-  /// SmallStorage - Fixed size storage used in 'small mode'.  The extra element
-  /// ensures that the end iterator actually points to valid memory.
-  const void *SmallStorage[SmallSizePowTwo+1];
+  /// SmallStorage - Fixed size storage used in 'small mode'.
+  const void *SmallStorage[SmallSizePowTwo];
   typedef PointerLikeTypeTraits<PtrType> PtrTraits;
 public:
   SmallPtrSet() : SmallPtrSetImpl(SmallStorage, SmallSizePowTwo) {}
@@ -273,10 +274,10 @@ public:
   typedef SmallPtrSetIterator<PtrType> iterator;
   typedef SmallPtrSetIterator<PtrType> const_iterator;
   inline iterator begin() const {
-    return iterator(CurArray);
+    return iterator(CurArray, CurArray+CurArraySize);
   }
   inline iterator end() const {
-    return iterator(CurArray+CurArraySize);
+    return iterator(CurArray+CurArraySize, CurArray+CurArraySize);
   }
 
   // Allow assignment from any smallptrset with the same element type even if it
@@ -287,8 +288,20 @@ public:
     return *this;
   }
 
+  /// swap - Swaps the elements of two sets.
+  void swap(SmallPtrSet<PtrType, SmallSize> &RHS) {
+    SmallPtrSetImpl::swap(RHS);
+  }
 };
 
 }
 
+namespace std {
+  /// Implement std::swap in terms of SmallPtrSet swap.
+  template<class T, unsigned N>
+  inline void swap(llvm::SmallPtrSet<T, N> &LHS, llvm::SmallPtrSet<T, N> &RHS) {
+    LHS.swap(RHS);
+  }
+}
+
 #endif