implement operator= for smallptrset
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@38460 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Support/SmallPtrSet.cpp b/lib/Support/SmallPtrSet.cpp
index da1a110..81c4bc7 100644
--- a/lib/Support/SmallPtrSet.cpp
+++ b/lib/Support/SmallPtrSet.cpp
@@ -13,6 +13,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Support/MathExtras.h"
using namespace llvm;
bool SmallPtrSetImpl::insert(void *Ptr) {
@@ -172,3 +173,38 @@
}
}
}
+
+/// CopyFrom - implement operator= from a smallptrset that has the same pointer
+/// type, but may have a different small size.
+void SmallPtrSetImpl::CopyFrom(const SmallPtrSetImpl &RHS) {
+ // Allocate space if needed or clear the current elements out of the array.
+ if (CurArraySize < RHS.size()*2) {
+ if (!isSmall())
+ delete [] CurArray;
+
+ // Get a power of two larger than twice the RHS size.
+ CurArraySize = 1 << Log2_32(RHS.size()*4);
+
+ // Install the new array. Clear all the buckets to empty.
+ CurArray = new void*[CurArraySize+1];
+ memset(CurArray, -1, CurArraySize*sizeof(void*));
+
+ // The end pointer, always valid, is set to a valid element to help the
+ // iterator.
+ CurArray[CurArraySize] = 0;
+
+ } else if (!empty()) {
+ clear();
+ }
+
+ // Now that we know we have enough space, and that the current array is empty,
+ // copy over all the elements from the RHS.
+
+ for (void **BucketPtr = RHS.CurArray, **E = RHS.CurArray+RHS.CurArraySize;
+ BucketPtr != E; ++BucketPtr) {
+ // Copy over the element if it is valid.
+ void *Elt = *BucketPtr;
+ if (Elt != getTombstoneMarker() && Elt != getEmptyMarker())
+ *const_cast<void**>(FindBucketFor(Elt)) = Elt;
+ }
+}