Allocate boxed static structs on Frozen Object Heap

src/coreclr/vm/jitinterface.cpp

@@ -1514,7 +1514,22 @@ void CEEInfo::getFieldInfo (CORINFO_RESOLVED_TOKEN * pResolvedToken,
             CORINFO_FIELD_ACCESSOR intrinsicAccessor;
 
             if (pField->GetFieldType() == ELEMENT_TYPE_VALUETYPE)
-                fieldFlags |= CORINFO_FLG_FIELD_STATIC_IN_HEAP;
+            {
+                bool frozenBoxedStatic = false;
+                if (pFieldMT->ContainsPointersOrCollectible())
+                {
+                    Object** handle = (Object**)pField->GetStaticAddressHandle(pField->GetBase());
+                    if (*handle == nullptr && GCHeapUtilities::GetGCHeap()->IsInFrozenSegment(*handle))
+                    {
+                        frozenBoxedStatic = true;
+                    }
+                }
+
+                if (!frozenBoxedStatic)
+                {
+                    fieldFlags |= CORINFO_FLG_FIELD_STATIC_IN_HEAP;
+                }
+            }
 
             if (pFieldMT->IsSharedByGenericInstantiations())
             {

src/coreclr/vm/methodtable.cpp

@@ -58,6 +58,7 @@
 #include "array.h"
 #include "castcache.h"
 #include "dynamicinterfacecastable.h"
+#include "frozenobjectheap.h"
 
 #ifdef FEATURE_INTERPRETER
 #include "interpreter.h"
@@ -3498,8 +3499,11 @@ void MethodTable::AllocateRegularStaticBoxes()
                 TypeHandle  th = pField->GetFieldTypeHandleThrowing();
                 MethodTable* pFieldMT = th.GetMethodTable();
 
+                bool neverCollected = !pFieldMT->ContainsPointersOrCollectible() &&
+                    !pField->GetApproxEnclosingMethodTable()->Collectible();
+
                 LOG((LF_CLASSLOADER, LL_INFO10000, "\tInstantiating static of type %s\n", pFieldMT->GetDebugClassName()));
-                OBJECTREF obj = AllocateStaticBox(pFieldMT, HasFixedAddressVTStatics());
+                OBJECTREF obj = AllocateStaticBox(pFieldMT, HasFixedAddressVTStatics(), NULL, neverCollected);
 
                 SetObjectReference( (OBJECTREF*)(pStaticBase + pField->GetOffset()), obj);
             }
@@ -3511,13 +3515,13 @@ void MethodTable::AllocateRegularStaticBoxes()
 }
 
 //==========================================================================================
-OBJECTREF MethodTable::AllocateStaticBox(MethodTable* pFieldMT, BOOL fPinned, OBJECTHANDLE* pHandle)
+OBJECTREF MethodTable::AllocateStaticBox(MethodTable* pFieldMT, BOOL fPinned, OBJECTHANDLE* pHandle, bool neverCollected)
 {
     CONTRACTL
     {
         THROWS;
         GC_TRIGGERS;
-        MODE_ANY;
+        MODE_COOPERATIVE;
         CONTRACTL_END;
     }
 
@@ -3526,7 +3530,21 @@ OBJECTREF MethodTable::AllocateStaticBox(MethodTable* pFieldMT, BOOL fPinned, OB
     // Activate any dependent modules if necessary
     pFieldMT->EnsureInstanceActive();
 
-    OBJECTREF obj = AllocateObject(pFieldMT);
+    OBJECTREF obj = NULL;
+    if (neverCollected)
+    {
+        // In case if we don't plan to collect this handle we may try to allocate it on FOH
+        _ASSERT(!pFieldMT->ContainsPointersOrCollectible());
+        FrozenObjectHeapManager* foh = SystemDomain::GetFrozenObjectHeapManager();
+        obj = ObjectToOBJECTREF(foh->TryAllocateObject(pFieldMT, pFieldMT->GetBaseSize()));
+        // obj can be null in case if struct is huge (>64kb)
+        if (obj != NULL)
+        {
+            return obj;
+        }
+    }
+
+    obj = AllocateObject(pFieldMT);
 
     // Pin the object if necessary
     if (fPinned)

src/coreclr/vm/methodtable.h

@@ -831,7 +831,7 @@ class MethodTable
     // instantiations of the superclass or interfaces e.g. System.Int32 : IComparable<System.Int32>
 
     void AllocateRegularStaticBoxes();
-    static OBJECTREF AllocateStaticBox(MethodTable* pFieldMT, BOOL fPinned, OBJECTHANDLE* pHandle = 0);
+    static OBJECTREF AllocateStaticBox(MethodTable* pFieldMT, BOOL fPinned, OBJECTHANDLE* pHandle = 0, bool neverCollected = false);
 
     void CheckRestore();