[llvm-commits] [llvm] r128566 - in /llvm/trunk: include/llvm/ADT/SmallPtrSet.h lib/Support/SmallPtrSet.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Wed Mar 30 13:32:48 2011
New Revision: 128566

URL: http://llvm.org/viewvc/llvm-project?rev=128566&view=rev
Log:
Prevent infinite growth of SmallPtrSet instances.

Rehash but don't grow when full of tombstones.

Patch by José Fonseca!

Modified:
    llvm/trunk/include/llvm/ADT/SmallPtrSet.h
    llvm/trunk/lib/Support/SmallPtrSet.cpp

Modified: llvm/trunk/include/llvm/ADT/SmallPtrSet.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/SmallPtrSet.h?rev=128566&r1=128565&r2=128566&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/SmallPtrSet.h (original)
+++ llvm/trunk/include/llvm/ADT/SmallPtrSet.h Wed Mar 30 13:32:48 2011
@@ -133,7 +133,7 @@
   void shrink_and_clear();
 
   /// Grow - Allocate a larger backing store for the buckets and move it over.
-  void Grow();
+  void Grow(unsigned NewSize);
 
   void operator=(const SmallPtrSetImpl &RHS);  // DO NOT IMPLEMENT.
 protected:

Modified: llvm/trunk/lib/Support/SmallPtrSet.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/SmallPtrSet.cpp?rev=128566&r1=128565&r2=128566&view=diff
==============================================================================
--- llvm/trunk/lib/Support/SmallPtrSet.cpp (original)
+++ llvm/trunk/lib/Support/SmallPtrSet.cpp Wed Mar 30 13:32:48 2011
@@ -52,10 +52,14 @@
     // 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();
+  if (NumElements*4 >= CurArraySize*3) {
+    // If more than 3/4 of the array is full, grow.
+    Grow(CurArraySize < 64 ? 128 : CurArraySize*2);
+  } else if (CurArraySize-(NumElements+NumTombstones) < CurArraySize/8) {
+    // If fewer of 1/8 of the array is empty (meaning that many are filled with
+    // tombstones), rehash.
+    Grow(CurArraySize);
+  }
   
   // Okay, we know we have space.  Find a hash bucket.
   const void **Bucket = const_cast<const void**>(FindBucketFor(Ptr));
@@ -125,10 +129,9 @@
 
 /// Grow - Allocate a larger backing store for the buckets and move it over.
 ///
-void SmallPtrSetImpl::Grow() {
+void SmallPtrSetImpl::Grow(unsigned NewSize) {
   // 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();