Feedback for GC method

dotnet · AaronRobinsonMSFT · Jan 26, 2024 · Jan 17, 2024 · Jan 24, 2024 · Jan 24, 2024
commit 7c5dbd03e22e89888f56d728442bed9bfc7dc53f
diff --git a/src/coreclr/System.Private.CoreLib/src/System/GC.CoreCLR.cs b/src/coreclr/System.Private.CoreLib/src/System/GC.CoreCLR.cs
@@ -287,13 +287,17 @@ public static void KeepAlive(object? obj)
         //
         public static int GetGeneration(WeakReference wo)
         {
-            int result = GetGenerationWR(wo.WeakHandle);
+            // Note - This throws an NRE if given a null weak reference.
+            object? obj = GCHandle.InternalGet(wo.WeakHandle);
             KeepAlive(wo);
-            return result;
-        }
 
-        [LibraryImport(RuntimeHelpers.QCall, EntryPoint = "GCInterface_GetGenerationWR")]
-        private static partial int GetGenerationWR(IntPtr handle);
+            if (obj is null)
+            {
+                throw new ArgumentNullException(nameof(wo));
+            }
+
+            return GetGeneration(obj);
+        }
 
         // Returns the maximum GC generation.  Currently assumes only 1 heap.
         //

diff --git a/src/coreclr/vm/comutilnative.cpp b/src/coreclr/vm/comutilnative.cpp
@@ -795,38 +795,6 @@ extern "C" int QCALLTYPE GCInterface_EndNoGCRegion()
     return retVal;
 }
 
-/*===============================GetGenerationWR================================
-**Action: Returns the generation in which the object pointed to by a WeakReference is found.
-**Returns:
-**Arguments: args->handle -- the OBJECTHANDLE to the object which we're locating.
-**Exceptions: ArgumentException if handle points to an object which is not accessible.
-==============================================================================*/
-extern "C" int QCALLTYPE GCInterface_GetGenerationWR(LPVOID handle)
-{
-    QCALL_CONTRACT;
-
-    int retVal = 0;
-
-    BEGIN_QCALL;
-
-    GCX_COOP();
-
-    OBJECTREF temp = NULL;
-    GCPROTECT_BEGIN(temp);
-
-    temp = ObjectFromHandle((OBJECTHANDLE) handle);
-    if (temp == NULL)
-        COMPlusThrowArgumentNull(W("wo"));
-
-    retVal = (INT32)GCHeapUtilities::GetGCHeap()->WhichGeneration(OBJECTREFToObject(temp));
-
-    GCPROTECT_END();
-
-    END_QCALL;
-
-    return retVal;
-}
-
 FCIMPL0(int, GCInterface::GetLastGCPercentTimeInGC)
 {
     FCALL_CONTRACT;

diff --git a/src/coreclr/vm/comutilnative.h b/src/coreclr/vm/comutilnative.h
@@ -214,8 +214,6 @@ extern "C" int QCALLTYPE GCInterface_StartNoGCRegion(INT64 totalSize, BOOL lohSi
 
 extern "C" int QCALLTYPE GCInterface_EndNoGCRegion();
 
-extern "C" int QCALLTYPE GCInterface_GetGenerationWR(LPVOID handle);
-
 extern "C" void QCALLTYPE GCInterface_AddMemoryPressure(UINT64 bytesAllocated);
 
 extern "C" void QCALLTYPE GCInterface_RemoveMemoryPressure(UINT64 bytesAllocated);

diff --git a/src/coreclr/vm/qcallentrypoints.cpp b/src/coreclr/vm/qcallentrypoints.cpp
@@ -243,7 +243,6 @@ static const Entry s_QCall[] =
     DllImportEntry(GCInterface_WaitForFullGCComplete)
     DllImportEntry(GCInterface_StartNoGCRegion)
     DllImportEntry(GCInterface_EndNoGCRegion)
-    DllImportEntry(GCInterface_GetGenerationWR)
     DllImportEntry(GCInterface_GetTotalMemory)
     DllImportEntry(GCInterface_Collect)
     DllImportEntry(GCInterface_WaitForPendingFinalizers)