[local gc] refactor apis for threading and suspension to avoid redundant calls in to the runtime (#16765)

* [Local GC] Refactor calls involving thread modes, suspension, and alloc contexts to always operate on current thread

* BOOL -> bool for enable/disable preemptive routines, also remove an unused call to GetThread

* avoid one indirection by having GCToEEInterface::EnablePreemptiveGC return a bool indicating whether the mode was changed

* Callback on IGCHeap for the runtime to notify the GC when it is trapping threads

* use g_fSuspensionPending instead of GCToEEInterface::CatchAtSafePoint for allow_fgc

* Remove CatchAtSafePoint

* Remove GetThread from WaitLongerNoInstru

* code review feedback

* code review feedback

* change BOOL to bool

1 files changed, 16 insertions, 9 deletions

diff --git a/src/gc/gcee.cpp b/src/gc/gcee.cpp
index b399cde14f..52f2eb3179 100644
--- a/src/gc/gcee.cpp
+++ b/src/gc/gcee.cpp
@@ -455,24 +455,19 @@ void gc_heap::fire_etw_pin_object_event (uint8_t* object, uint8_t** ppObject)
 uint32_t gc_heap::user_thread_wait (GCEvent *event, BOOL no_mode_change, int time_out_ms)
 {
     Thread* pCurThread = NULL;
-    bool mode = false;
+    bool bToggleGC = false;
     uint32_t dwWaitResult = NOERROR;
     
     if (!no_mode_change)
     {
-        pCurThread = GCToEEInterface::GetThread();
-        mode = pCurThread ? GCToEEInterface::IsPreemptiveGCDisabled(pCurThread) : false;
-        if (mode)
-        {
-            GCToEEInterface::EnablePreemptiveGC(pCurThread);
-        }
+        bToggleGC = GCToEEInterface::EnablePreemptiveGC();
     }
 
     dwWaitResult = event->Wait(time_out_ms, FALSE);
 
-    if (!no_mode_change && mode)
+    if (bToggleGC)
     {
-        GCToEEInterface::DisablePreemptiveGC(pCurThread);
+        GCToEEInterface::DisablePreemptiveGC();
     }
 
     return dwWaitResult;
@@ -608,6 +603,18 @@ bool GCHeap::RuntimeStructuresValid()
     return GCScan::GetGcRuntimeStructuresValid();
 }
 
+void GCHeap::SetSuspensionPending(bool fSuspensionPending)
+{
+    if (fSuspensionPending)
+    {
+        Interlocked::Increment(&g_fSuspensionPending);
+    }
+    else
+    {
+        Interlocked::Decrement(&g_fSuspensionPending);
+    }
+}
+
 void GCHeap::ControlEvents(GCEventKeyword keyword, GCEventLevel level)
 {
     GCEventStatus::Set(GCEventProvider_Default, keyword, level);