[Arm64] Optimize JIT_WriteBarriers

Fixes #5833
Fixes #11374
Fixes #12197

1 files changed, 13 insertions, 1 deletions

diff --git a/src/vm/gcenv.ee.cpp b/src/vm/gcenv.ee.cpp
index b61069f5fd..b135173c0f 100644
--- a/src/vm/gcenv.ee.cpp
+++ b/src/vm/gcenv.ee.cpp
@@ -861,7 +861,7 @@ void GCToEEInterface::StompWriteBarrier(WriteBarrierParameters* args)
 #endif
 
 #ifdef FEATURE_USE_SOFTWARE_WRITE_WATCH_FOR_GC_HEAP
-        if (args->write_watch_table != nullptr)
+        if (g_sw_ww_enabled_for_gc_heap && (args->write_watch_table != nullptr))
         {
             assert(args->is_runtime_suspended);
             g_sw_ww_table = args->write_watch_table;
@@ -888,6 +888,17 @@ void GCToEEInterface::StompWriteBarrier(WriteBarrierParameters* args)
 
         g_lowest_address = args->lowest_address;
         VolatileStore(&g_highest_address, args->highest_address);
+
+#if defined(_ARM64_)
+        // Need to reupdate for changes to g_highest_address g_lowest_address
+        ::StompWriteBarrierResize(args->is_runtime_suspended, args->requires_upper_bounds_check);
+
+        if(!args->is_runtime_suspended)
+        {
+            // If runtime is not suspended, force updated state to be visible to all threads
+            MemoryBarrier();
+        }
+#endif
         return;
     case WriteBarrierOp::StompEphemeral:
         // StompEphemeral requires a new ephemeral low and a new ephemeral high
@@ -945,6 +956,7 @@ void GCToEEInterface::StompWriteBarrier(WriteBarrierParameters* args)
     case WriteBarrierOp::SwitchToNonWriteWatch:
 #ifdef FEATURE_USE_SOFTWARE_WRITE_WATCH_FOR_GC_HEAP
         assert(args->is_runtime_suspended && "the runtime must be suspended here!");
+        g_sw_ww_table = 0;
         g_sw_ww_enabled_for_gc_heap = false;
         ::SwitchToNonWriteWatchBarrier(true);
 #else