Changes in directory llvm/lib/Support:
SmallPtrSet.cpp added (r1.1) --- Log message: Add a new SmallSet ADT specialized for pointers. --- Diffs of the changes: (+113 -0) SmallPtrSet.cpp | 113 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 113 insertions(+) Index: llvm/lib/Support/SmallPtrSet.cpp diff -c /dev/null llvm/lib/Support/SmallPtrSet.cpp:1.1 *** /dev/null Sat Jan 27 01:10:56 2007 --- llvm/lib/Support/SmallPtrSet.cpp Sat Jan 27 01:10:46 2007 *************** *** 0 **** --- 1,113 ---- + //===- llvm/ADT/SmallPtrSet.cpp - 'Normally small' pointer set ------------===// + // + // 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 implements the SmallPtrSet class. + // + //===----------------------------------------------------------------------===// + + #include "llvm/ADT/SmallPtrSet.h" + using namespace llvm; + + bool SmallPtrSetImpl::insert(void *Ptr) { + if (isSmall()) { + // Check to see if it is already in the set. + for (void **APtr = SmallArray, **E = SmallArray+NumElements; + APtr != E; ++APtr) + if (*APtr == Ptr) + return false; + + // Nope, there isn't. If we stay small, just 'pushback' now. + if (NumElements < CurArraySize-1) { + SmallArray[NumElements++] = Ptr; + return true; + } + // Otherwise, hit the big set case, which will call grow. + } + + // If more than 3/4 of the array is full, grow. + if (NumElements*4 >= CurArraySize*3) + Grow(); + + // Okay, we know we have space. Find a hash bucket. + void **Bucket = const_cast<void**>(FindBucketFor(Ptr)); + if (*Bucket == Ptr) return false; // Already inserted, good. + + // Otherwise, insert it! + *Bucket = Ptr; + ++NumElements; // Track density. + return true; + } + + void * const *SmallPtrSetImpl::FindBucketFor(void *Ptr) const { + unsigned Bucket = Hash(Ptr); + unsigned ArraySize = CurArraySize; + unsigned ProbeAmt = 1; + void *const *Array = CurArray; + void *const *Tombstone = 0; + while (1) { + // Found Ptr's bucket? + if (Array[Bucket] == Ptr) + return Array+Bucket; + + // If we found an empty bucket, the pointer doesn't exist in the set. + // Return a tombstone if we've seen one so far, or the empty bucket if + // not. + if (Array[Bucket] == getEmptyMarker()) + return Tombstone ? Tombstone : Array+Bucket; + + // If this is a tombstone, remember it. If Ptr ends up not in the set, we + // prefer to return it than something that would require more probing. + if (Array[Bucket] == getTombstoneMarker() && !Tombstone) + Tombstone = Array+Bucket; // Remember the first tombstone found. + + // It's a hash collision or a tombstone. Reprobe. + Bucket = (Bucket + ProbeAmt++) & (ArraySize-1); + } + } + + /// Grow - Allocate a larger backing store for the buckets and move it over. + /// + void SmallPtrSetImpl::Grow() { + // Allocate at twice as many buckets, but at least 128. + unsigned OldSize = CurArraySize; + unsigned NewSize = OldSize < 64 ? 128 : OldSize*2; + + void **OldBuckets = CurArray; + bool WasSmall = isSmall(); + + // Install the new array. Clear all the buckets to empty. + CurArray = new void*[NewSize+1]; + CurArraySize = NewSize; + memset(CurArray, -1, NewSize*sizeof(void*)); + + // The end pointer, always valid, is set to a valid element to help the + // iterator. + CurArray[NewSize] = 0; + + // Copy over all the elements. + if (WasSmall) { + // Small sets store their elements in order. + for (void **BucketPtr = OldBuckets, **E = OldBuckets+NumElements; + BucketPtr != E; ++BucketPtr) { + void *Elt = *BucketPtr; + *const_cast<void**>(FindBucketFor(Elt)) = Elt; + } + } else { + // Copy over all valid entries. + for (void **BucketPtr = OldBuckets, **E = OldBuckets+OldSize; + 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; + } + + delete [] OldBuckets; + } + } _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits