Bug 650161 - Fix a bug than meant we relocated fewer arenas than we should have r=terrence

js/src/jsgc.cpp

@@ -2082,20 +2082,6 @@ size_t ArenaHeader::countUsedCells()
     return Arena::thingsPerArena(getThingSize()) - countFreeCells();
 }
 
-/*
- * Iterate throught the list and count the number of cells used.
- *
- * We may be able to precalculate this while sweeping and store the result
- * somewhere.
- */
-size_t ArenaList::countUsedCells()
-{
-    size_t count = 0;
-    for (ArenaHeader *arena = head_; arena; arena = arena->next)
-        count += arena->countUsedCells();
-    return count;
-}
-
 ArenaHeader *
 ArenaList::removeRemainingArenas(ArenaHeader **arenap, const AutoLockGC &lock)
 {
@@ -2153,7 +2139,12 @@ ArenaList::pickArenasToRelocate(JSRuntime *runtime)
 
     ArenaHeader **arenap = cursorp_;               // Next arena to consider
     size_t previousFreeCells = 0;                  // Count of free cells before
-    size_t followingUsedCells = countUsedCells();  // Count of used cells after
+
+    // Count of used cells after arenap.
+    size_t followingUsedCells = 0;
+    for (ArenaHeader *arena = *arenap; arena; arena = arena->next)
+        followingUsedCells += arena->countUsedCells();
+
     mozilla::DebugOnly<size_t> lastFreeCells(0);
     size_t cellsPerArena = Arena::thingsPerArena((*arenap)->getThingSize());
 

js/src/jsgc.h

@@ -503,7 +503,6 @@ class ArenaList {
     }
 
 #ifdef JSGC_COMPACTING
-    size_t countUsedCells();
     ArenaHeader *removeRemainingArenas(ArenaHeader **arenap, const AutoLockGC &lock);
     ArenaHeader *pickArenasToRelocate(JSRuntime *runtime);
     ArenaHeader *relocateArenas(ArenaHeader *toRelocate, ArenaHeader *relocated);