replace SfxPoolItem::LookupHashCode() with Lookup() (tdf#135215)

The LookupHashCode() way still loops over an array while calling
virtual functions for a type that is actually known. Overriding
instead a whole new Lookup() function that does the loop
avoids the virtual calls, allowing compiler optimizations such
as inlining, or class-specific optimizations like the hash code.
So this still improves performance with ScPatternAttr a bit,
for tdf#135215 it saves about 40% of load time, but this is
scraping the bottom of the barrel, as this is still a linear search
(the IsSortable() approach, if it worked, would be still 3x faster).

Change-Id: I8fe5f70cabb77e2f6619d169beee8a3b4da46213
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/130228
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

2 files changed, 10 insertions, 25 deletions

diff --git a/svl/source/items/itempool.cxx b/svl/source/items/itempool.cxx
index acd5c77de452..e13a1ffd60ea 100644
--- a/svl/source/items/itempool.cxx
+++ b/svl/source/items/itempool.cxx
@@ -625,30 +625,20 @@ const SfxPoolItem& SfxItemPool::PutImpl( const SfxPoolItem& rItem, sal_uInt16 nW
             if (pFoundItem)
                 assert(*pFoundItem == rItem);
         }
+        else if(rItem.HasLookup())
+        {
+            auto it = rItem.Lookup(rItemArr.begin(), rItemArr.end());
+            if( it != rItemArr.end())
+                pFoundItem = *it;
+        }
         else
         {
-            // If the item provides a valid hash, use that to speed up comparisons.
-            size_t lookupHashCode = rItem.LookupHashCode();
-            if (lookupHashCode != 0)
+            for (auto it = rItemArr.begin(); it != rItemArr.end(); ++it)
             {
-                for (auto itr = rItemArr.begin(); itr != rItemArr.end(); ++itr)
+                if (**it == rItem)
                 {
-                    if ((*itr)->LookupHashCode() == lookupHashCode && **itr == rItem)
-                    {
-                        pFoundItem = *itr;
-                        break;
-                    }
-                }
-            }
-            else
-            {
-                for (auto itr = rItemArr.begin(); itr != rItemArr.end(); ++itr)
-                {
-                    if (**itr == rItem)
-                    {
-                        pFoundItem = *itr;
-                        break;
-                    }
+                    pFoundItem = *it;
+                    break;
                 }
             }
         }
diff --git a/svl/source/items/sitem.cxx b/svl/source/items/sitem.cxx
index c4734d35c2f2..b6ffce978aef 100644
--- a/svl/source/items/sitem.cxx
+++ b/svl/source/items/sitem.cxx
@@ -51,11 +51,6 @@ SfxSetItem::SfxSetItem( const SfxSetItem& rCopy, SfxItemPool *pPool ) :
 }
 
 
-SfxSetItem::~SfxSetItem()
-{
-}
-
-
 bool SfxSetItem::operator==( const SfxPoolItem& rCmp) const
 {
     assert(SfxPoolItem::operator==(rCmp));