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

This time tested on both OSX and Linux.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178377 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 18 insertions, 17 deletions

diff --git a/include/llvm/ADT/SmallPtrSet.h b/include/llvm/ADT/SmallPtrSet.h
index 3bb8830..8c73041 100644
--- a/include/llvm/ADT/SmallPtrSet.h
+++ b/include/llvm/ADT/SmallPtrSet.h
@@ -54,8 +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
@@ -68,9 +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();
@@ -147,9 +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 {
@@ -164,8 +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;
   }
 };
@@ -182,12 +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));
   }
 
@@ -236,9 +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) {}
@@ -275,10 +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
diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h
index 9167f87..7ba0a71 100644
--- a/include/llvm/ADT/SmallVector.h
+++ b/include/llvm/ADT/SmallVector.h
@@ -16,6 +16,7 @@
 
 #include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Compiler.h"
+#include "llvm/Support/MathExtras.h"
 #include "llvm/Support/type_traits.h"
 #include <algorithm>
 #include <cassert>
@@ -267,7 +268,8 @@ template <typename T, bool isPodLike>
 void SmallVectorTemplateBase<T, isPodLike>::grow(size_t MinSize) {
   size_t CurCapacity = this->capacity();
   size_t CurSize = this->size();
-  size_t NewCapacity = 2*CurCapacity + 1; // Always grow, even from zero.
+  // Always grow, even from zero.  
+  size_t NewCapacity = size_t(NextPowerOf2(CurCapacity+2));
   if (NewCapacity < MinSize)
     NewCapacity = MinSize;
   T *NewElts = static_cast<T*>(malloc(NewCapacity*sizeof(T)));