Move SwapBitmaps to ContinuousMemMapAllocSpace.

Moved the SwapBitmaps function to ContinuousMemMapAllocSpace since
the zygote space uses this function during full GC.

Fixed a place where we were casting a ZygoteSpace to a MallocSpace,
somehow this didn't cause any issues in non-debug builds.

Moved the CollectGarbage in PreZygoteFork before the lock to prevent
an occasional lock level violation caused by attempting to enqueue
java lang references with the a lock.

Bug: 12876255

Change-Id: I77439e46d5b26b37724bdcee3a0948410f1b0eb4

1 files changed, 3 insertions, 2 deletions

diff --git a/runtime/gc/collector/garbage_collector.cc b/runtime/gc/collector/garbage_collector.cc
index 25e8966..ae04074 100644
--- a/runtime/gc/collector/garbage_collector.cc
+++ b/runtime/gc/collector/garbage_collector.cc
@@ -151,10 +151,11 @@ void GarbageCollector::SwapBitmaps() {
          space->GetGcRetentionPolicy() == space::kGcRetentionPolicyFullCollect)) {
       accounting::SpaceBitmap* live_bitmap = space->GetLiveBitmap();
       accounting::SpaceBitmap* mark_bitmap = space->GetMarkBitmap();
-      if (live_bitmap != mark_bitmap) {
+      if (live_bitmap != nullptr && live_bitmap != mark_bitmap) {
         heap_->GetLiveBitmap()->ReplaceBitmap(live_bitmap, mark_bitmap);
         heap_->GetMarkBitmap()->ReplaceBitmap(mark_bitmap, live_bitmap);
-        space->AsMallocSpace()->SwapBitmaps();
+        CHECK(space->IsContinuousMemMapAllocSpace());
+        space->AsContinuousMemMapAllocSpace()->SwapBitmaps();
       }
     }
   }