[llvm-commits] [llvm] r128565 - in /llvm/trunk: include/llvm/ADT/StringMap.h lib/Support/StringMap.cpp
Jakob Stoklund Olesen
stoklund at 2pi.dk
Wed Mar 30 11:32:45 PDT 2011
Author: stoklund
Date: Wed Mar 30 13:32:44 2011
New Revision: 128565
URL: http://llvm.org/viewvc/llvm-project?rev=128565&view=rev
Log:
Prevent infinite growth of SmallMap instances.
Rehash but don't grow when full of tombstones.
Patch by José Fonseca!
Modified:
llvm/trunk/include/llvm/ADT/StringMap.h
llvm/trunk/lib/Support/StringMap.cpp
Modified: llvm/trunk/include/llvm/ADT/StringMap.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/StringMap.h?rev=128565&r1=128564&r2=128565&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/StringMap.h (original)
+++ llvm/trunk/include/llvm/ADT/StringMap.h Wed Mar 30 13:32:44 2011
@@ -81,16 +81,6 @@
StringMapImpl(unsigned InitSize, unsigned ItemSize);
void RehashTable();
- /// ShouldRehash - Return true if the table should be rehashed after a new
- /// element was recently inserted.
- bool ShouldRehash() const {
- // If the hash table is now more than 3/4 full, or if fewer than 1/8 of
- // the buckets are empty (meaning that many are filled with tombstones),
- // grow the table.
- return NumItems*4 > NumBuckets*3 ||
- NumBuckets-(NumItems+NumTombstones) < NumBuckets/8;
- }
-
/// LookupBucketFor - Look up the bucket that the specified string should end
/// up in. If it already exists as a key in the map, the Item pointer for the
/// specified bucket will be non-null. Otherwise, it will be null. In either
@@ -340,8 +330,7 @@
Bucket.Item = KeyValue;
++NumItems;
- if (ShouldRehash())
- RehashTable();
+ RehashTable();
return true;
}
@@ -383,8 +372,7 @@
// filled in by LookupBucketFor.
Bucket.Item = NewItem;
- if (ShouldRehash())
- RehashTable();
+ RehashTable();
return *NewItem;
}
Modified: llvm/trunk/lib/Support/StringMap.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/StringMap.cpp?rev=128565&r1=128564&r2=128565&view=diff
==============================================================================
--- llvm/trunk/lib/Support/StringMap.cpp (original)
+++ llvm/trunk/lib/Support/StringMap.cpp Wed Mar 30 13:32:44 2011
@@ -177,7 +177,19 @@
/// RehashTable - Grow the table, redistributing values into the buckets with
/// the appropriate mod-of-hashtable-size.
void StringMapImpl::RehashTable() {
- unsigned NewSize = NumBuckets*2;
+ unsigned NewSize;
+
+ // If the hash table is now more than 3/4 full, or if fewer than 1/8 of
+ // the buckets are empty (meaning that many are filled with tombstones),
+ // grow/rehash the table.
+ if (NumItems*4 > NumBuckets*3) {
+ NewSize = NumBuckets*2;
+ } else if (NumBuckets-(NumItems+NumTombstones) < NumBuckets/8) {
+ NewSize = NumBuckets;
+ } else {
+ return;
+ }
+
// Allocate one extra bucket which will always be non-empty. This allows the
// iterators to stop at end.
ItemBucket *NewTableArray =(ItemBucket*)calloc(NewSize+1, sizeof(ItemBucket));
More information about the llvm-commits
mailing list