1 files changed, 223 insertions, 0 deletions
diff --git a/lib/Support/SmallPtrSet.cpp b/lib/Support/SmallPtrSet.cpp
new file mode 100644
index 0000000000000..68938fa5a5716
--- /dev/null
+++ b/lib/Support/SmallPtrSet.cpp
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+//===- llvm/ADT/SmallPtrSet.cpp - 'Normally small' pointer set ------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements the SmallPtrSet class.  See SmallPtrSet.h for an
+// overview of the algorithm.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/Support/MathExtras.h"
+#include <cstdlib>
+
+using namespace llvm;
+
+void SmallPtrSetImpl::shrink_and_clear() {
+  assert(!isSmall() && "Can't shrink a small set!");
+  free(CurArray);
+
+  // Reduce the number of buckets.
+  CurArraySize = NumElements > 16 ? 1 << (Log2_32_Ceil(NumElements) + 1) : 32;
+  NumElements = NumTombstones = 0;
+
+  // Install the new array.  Clear all the buckets to empty.
+  CurArray = (const void**)malloc(sizeof(void*) * (CurArraySize+1));
+  assert(CurArray && "Failed to allocate memory?");
+  memset(CurArray, -1, CurArraySize*sizeof(void*));
+  
+  // The end pointer, always valid, is set to a valid element to help the
+  // iterator.
+  CurArray[CurArraySize] = 0;
+}
+
+bool SmallPtrSetImpl::insert_imp(const void * Ptr) {
+  if (isSmall()) {
+    // Check to see if it is already in the set.
+    for (const 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 ||
+      CurArraySize-(NumElements+NumTombstones) < CurArraySize/8)
+    Grow();
+  
+  // Okay, we know we have space.  Find a hash bucket.
+  const void **Bucket = const_cast<const void**>(FindBucketFor(Ptr));
+  if (*Bucket == Ptr) return false; // Already inserted, good.
+  
+  // Otherwise, insert it!
+  if (*Bucket == getTombstoneMarker())
+    --NumTombstones;
+  *Bucket = Ptr;
+  ++NumElements;  // Track density.
+  return true;
+}
+
+bool SmallPtrSetImpl::erase_imp(const void * Ptr) {
+  if (isSmall()) {
+    // Check to see if it is in the set.
+    for (const void **APtr = SmallArray, **E = SmallArray+NumElements;
+         APtr != E; ++APtr)
+      if (*APtr == Ptr) {
+        // If it is in the set, replace this element.
+        *APtr = E[-1];
+        E[-1] = getEmptyMarker();
+        --NumElements;
+        return true;
+      }
+    
+    return false;
+  }
+  
+  // Okay, we know we have space.  Find a hash bucket.
+  void **Bucket = const_cast<void**>(FindBucketFor(Ptr));
+  if (*Bucket != Ptr) return false;  // Not in the set?
+
+  // Set this as a tombstone.
+  *Bucket = getTombstoneMarker();
+  --NumElements;
+  ++NumTombstones;
+  return true;
+}
+
+const void * const *SmallPtrSetImpl::FindBucketFor(const void *Ptr) const {
+  unsigned Bucket = Hash(Ptr);
+  unsigned ArraySize = CurArraySize;
+  unsigned ProbeAmt = 1;
+  const void *const *Array = CurArray;
+  const 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;
+  
+  const void **OldBuckets = CurArray;
+  bool WasSmall = isSmall();
+  
+  // Install the new array.  Clear all the buckets to empty.
+  CurArray = (const void**)malloc(sizeof(void*) * (NewSize+1));
+  assert(CurArray && "Failed to allocate memory?");
+  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 (const void **BucketPtr = OldBuckets, **E = OldBuckets+NumElements;
+         BucketPtr != E; ++BucketPtr) {
+      const void *Elt = *BucketPtr;
+      *const_cast<void**>(FindBucketFor(Elt)) = const_cast<void*>(Elt);
+    }
+  } else {
+    // Copy over all valid entries.
+    for (const void **BucketPtr = OldBuckets, **E = OldBuckets+OldSize;
+         BucketPtr != E; ++BucketPtr) {
+      // Copy over the element if it is valid.
+      const void *Elt = *BucketPtr;
+      if (Elt != getTombstoneMarker() && Elt != getEmptyMarker())
+        *const_cast<void**>(FindBucketFor(Elt)) = const_cast<void*>(Elt);
+    }
+    
+    free(OldBuckets);
+    NumTombstones = 0;
+  }
+}
+
+SmallPtrSetImpl::SmallPtrSetImpl(const SmallPtrSetImpl& that) {
+  // If we're becoming small, prepare to insert into our stack space
+  if (that.isSmall()) {
+    CurArray = &SmallArray[0];
+  // Otherwise, allocate new heap space (unless we were the same size)
+  } else {
+    CurArray = (const void**)malloc(sizeof(void*) * (that.CurArraySize+1));
+    assert(CurArray && "Failed to allocate memory?");
+  }
+  
+  // Copy over the new array size
+  CurArraySize = that.CurArraySize;
+
+  // Copy over the contents from the other set
+  memcpy(CurArray, that.CurArray, sizeof(void*)*(CurArraySize+1));
+  
+  NumElements = that.NumElements;
+  NumTombstones = that.NumTombstones;
+}
+
+/// 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) {
+  if (isSmall() && RHS.isSmall())
+    assert(CurArraySize == RHS.CurArraySize &&
+           "Cannot assign sets with different small sizes");
+           
+  // If we're becoming small, prepare to insert into our stack space
+  if (RHS.isSmall()) {
+    if (!isSmall())
+      free(CurArray);
+    CurArray = &SmallArray[0];
+  // Otherwise, allocate new heap space (unless we were the same size)
+  } else if (CurArraySize != RHS.CurArraySize) {
+    if (isSmall())
+      CurArray = (const void**)malloc(sizeof(void*) * (RHS.CurArraySize+1));
+    else
+      CurArray = (const void**)realloc(CurArray, sizeof(void*)*(RHS.CurArraySize+1));
+    assert(CurArray && "Failed to allocate memory?");
+  }
+  
+  // Copy over the new array size
+  CurArraySize = RHS.CurArraySize;
+
+  // Copy over the contents from the other set
+  memcpy(CurArray, RHS.CurArray, sizeof(void*)*(CurArraySize+1));
+  
+  NumElements = RHS.NumElements;
+  NumTombstones = RHS.NumTombstones;
+}
+
+SmallPtrSetImpl::~SmallPtrSetImpl() {
+  if (!isSmall())
+    free(CurArray);
+}