#include <cassert>
#include <cstring>
+#include "llvm/Support/DataTypes.h"
namespace llvm {
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.
// If small, this is # elts allocated consequtively
unsigned NumElements;
- void *SmallArray[1]; // Must be last ivar.
+ unsigned NumTombstones;
+ const void *SmallArray[1]; // Must be last ivar.
+
+ // Helper to copy construct a SmallPtrSet.
+ SmallPtrSetImpl(const SmallPtrSetImpl& that);
public:
SmallPtrSetImpl(unsigned SmallSize) {
assert(SmallSize && (SmallSize & (SmallSize-1)) == 0 &&
CurArray[SmallSize] = 0;
clear();
}
- ~SmallPtrSetImpl() {
- if (!isSmall())
- delete[] CurArray;
- }
+ ~SmallPtrSetImpl();
+
+ bool empty() const { return size() == 0; }
+ unsigned size() const { return NumElements; }
- bool isSmall() const { return CurArray == &SmallArray[0]; }
-
static void *getTombstoneMarker() { return reinterpret_cast<void*>(-2); }
static void *getEmptyMarker() {
// Note that -1 is chosen to make clear() efficiently implementable with
}
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;
}
- /// insert - This returns true if the pointer was new to the set, false if it
- /// was already in the set.
- bool insert(void *Ptr);
+protected:
+ /// 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);
- bool count(void *Ptr) const {
+ /// 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;
}
private:
- unsigned Hash(void *Ptr) const {
+ bool isSmall() const { return CurArray == &SmallArray[0]; }
+
+ unsigned Hash(const void *Ptr) const {
return ((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) {
+ SmallPtrSetIteratorImpl(const void *const *BP) : Bucket(BP) {
AdvanceIfNotValid();
}
template<typename PtrTy>
class SmallPtrSetIterator : public SmallPtrSetIteratorImpl {
public:
- SmallPtrSetIterator(void *const *BP) : SmallPtrSetIteratorImpl(BP) {}
+ 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 static_cast<const PtrTy>(const_cast<void*>(*Bucket));
}
inline SmallPtrSetIterator& operator++() { // Preincrement
}
};
+/// 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
+ };
+};
-/// SmallPtrSet - This class implements
+template<unsigned N>
+struct NextPowerOfTwo {
+ enum { Val = NextPowerOfTwoH<N, (N&(N-1)) == 0>::Val };
+};
+
+
+/// 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];
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(Ptr); }
+
+ /// erase - If the set contains the specified pointer, remove it and return
+ /// true, otherwise return false.
+ bool erase(PtrType Ptr) { return erase_imp(Ptr); }
+
+ /// count - Return true if the specified pointer is in the set.
+ bool count(PtrType Ptr) const { return count_imp(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 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;
+ }
+
};
}
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