singrdk/base/Imported/Bartok/runtime/shared/System/VTable.cs

//
// Copyright (c) Microsoft Corporation.  All rights reserved.
//

/*******************************************************************/
/*                           WARNING                               */
/* This file should be identical in the Bartok and Singularity     */
/* depots. Master copy resides in Bartok Depot. Changes should be  */
/* made to Bartok Depot and propagated to Singularity Depot.       */
/*******************************************************************/


#define OLD_FAST_TESTS
#if MARKSWEEPCOLLECTOR
#define ALLOW_BOOT_ARGLIST
#endif

namespace System {

    using Microsoft.Bartok.Runtime;
#if SINGULARITY_KERNEL
    using Microsoft.Singularity;
#elif SINGULARITY_PROCESS
    using Microsoft.Singularity;
    using Microsoft.Singularity.V1.Services;
#endif
    using System.Reflection;
    using System.Runtime.CompilerServices;
    using System.Runtime.InteropServices;
    using System.Threading;
    using System;

    internal sealed class MutableInt32 {
        public MutableInt32(int x) { this.val = x; }
        public int Value { get { return this.val; } set { this.val = value; } }
        private int val;
    }

    [RequiredByBartok]
    internal struct InterfaceInfo {
        [RequiredByBartok]
        internal System.RuntimeType type;
        [RequiredByBartok]
        internal IntPtr offset;
    }

    [StructLayout(LayoutKind.Sequential)]
    [CCtorIsRunDuringStartup]
    [NoLoggingForUndo]
    [RequiredByBartok]
    [AccessedByRuntime("Referenced from brt{main,exn}.cpp and brtasm.asm")]
    internal sealed class VTable {
        [RequiredByBartok]
        [NoBarriers]
        public readonly VTable depth1;
        [NoBarriers]
        [RequiredByBartok]
        public readonly VTable depth2;
        [NoBarriers]
        [RequiredByBartok]
        public readonly VTable depth3;
        [NoBarriers]
        [RequiredByBartok]
        public readonly VTable depth4;
        [NoBarriers]
        [RequiredByBartok]
        public readonly VTable depth5;
        [NoBarriers]
        [RequiredByBartok]
        public readonly VTable depth6;
        [NoBarriers]
        public VTable posCache;
        [RequiredByBartok]
        [NoBarriers]
        public int depth;
        [RequiredByBartok]
        [NoBarriers]
        public readonly StructuralType arrayOf;
        [RequiredByBartok]
        [NoBarriers]
        public readonly VTable arrayElementClass;
        [RequiredByBartok]
        [NoBarriers]
        public readonly int arrayElementSize;
        [RequiredByBartok]
        [NoBarriers]
        public readonly InterfaceInfo[] interfaces;
        [RequiredByBartok]
        [NoBarriers]
        public readonly uint baseLength;
        [RequiredByBartok]
        [NoBarriers]
        public readonly uint baseAlignment;
        [RequiredByBartok]
        [NoBarriers]
        public readonly UIntPtr pointerTrackingMask;
        [RequiredByBartok]
        [NoBarriers]
        public readonly StructuralType structuralView;
        [AccessedByRuntime("Referenced from C++")]
        [NoBarriers]
        public readonly RuntimeType vtableType;
        [RequiredByBartok]
        [NoBarriers]
        public readonly int marshalSize;
        [RequiredByBartok]
        [NoBarriers]
        public readonly VTable vectorClass;
        [AccessedByRuntime("Type information available to runtime.")]
        [NoBarriers]
        public readonly bool isAcyclicRefType;

        // one less than size, which must be a power of two
        [NoBarriers]
        internal static int tryAllCheckMask = 2047;
#if SINGULARITY_KERNEL
        private static bool multiThreaded;
#endif

        internal class ClassConstructorLock
        {
        }

        [NoBarriers]
        public static readonly ClassConstructorLock cctorLock = new ClassConstructorLock();
        [NoBarriers]
        public static int[] handle_counts = new int[4];
        [NoBarriers]
        public static bool runtimeInitialized = false;
        [NoBarriers]
        public static System.Collections.Hashtable interfaceOffsetTable;
        [NoBarriers]
        public static bool callTraceInProgress;

#if ARM
        // TODO: ARM isn't supported by the BartokLinker yet, so this
        //       function won't be correctly generated.
        [StackBound(252)]
        [RequiredByBartok]
        private static void Initialize() {
        }

#else
        // This method is generated by Bartok.
        // It calls all the auto init class constructors.
        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(252)]
        [RequiredByBartok]
        private static extern void Initialize();
#endif

        // NB: This is called from Kernel.Main() before the VTable.cctor.
        // It calls all the manual init class constructors then
        // call Initialize() above to call the auto init class constructors.
        [AccessedByRuntime("called from brtmain.cpp")]
        [NoStackLinkCheck]
        static public void Initialize(RuntimeType mainType)
        {
            initializeGC();

#if !SINGULARITY
            if (useLinkedStack) {
                System.GCs.StackManager.Initialize();
            }
#endif // !SINGULARITY

            // The remaining cctors may allocate memory normally
#if !SINGULARITY
            InitializeLimitedType(typeof(Microsoft.Win32.Win32Native));
#endif
            InitializeLimitedType(typeof(System.Delegate));
            InitializeLimitedType(typeof(System.MultiUseWord));
            InitializeLimitedType(typeof(System.WeakReference));
            InitializeLimitedType(typeof(System.GCs.Verifier));
            InitializeLimitedType(typeof(System.Collections.Hashtable));

            Thread.FinishInitializeThread();

            // Make transition to full thread-ready GC.
            // We can't start any other threads until this code runs.
            System.GC.FinishInitializeThread();

#if !SINGULARITY
            InitializeLimitedType(typeof(System.IO.Stream));
            InitializeLimitedType(typeof(System.Reflection.Missing));
            InitializeLimitedType(typeof(System.RuntimeType));
            InitializeLimitedType(typeof(System.Environment));
#endif
#if SINGULARITY
            InitializeLimitedType(typeof(System.DateTime));
            InitializeLimitedType(typeof(System.TimeSpan));
            InitializeLimitedType(typeof(System.SchedulerTime));
#endif
            InitializeLimitedType(typeof(System.Type));
            InitializeLimitedType(typeof(System.String));
            InitializeLimitedType(typeof(System.BitConverter));
            InitializeLimitedType(typeof(System.Math));
            InitializeLimitedType(typeof(System.VTable));

#if !VC
            InitializeLimitedType(typeof(System.TryAllManager));
            InitializeLimitedType(typeof(System.TryAllCounters));
#endif

            VTable.runtimeInitialized = true;
            VTable.Initialize();
#if !SINGULARITY
            GC.EnableHeap();
            if(mainType != null) {
                initType(mainType);
            }
#endif
        }

#if SINGULARITY_KERNEL
        static public void InitializeForMultipleThread()
        {
            multiThreaded = true;
        }
#endif

#if (REFERENCE_COUNTING_GC || DEFERRED_REFERENCE_COUNTING_GC)
        [NoInline]
#endif // REFERENCE_COUNTING_GC
        [NoBarriers]
        [PreInitRefCounts]
        private static void initializeGC() {
            // Create the heap management data structures
            System.GC.ConstructHeap();
            // The following cctors may only allocate using BootstrapMemory
            InitializeLimitedType(typeof(System.Threading.Thread));
            InitializeLimitedType(typeof(System.GC));
            InitializeLimitedType(typeof(System.Finalizer));
            System.GCs.BootstrapMemory.Truncate();
        }

        [RequiredByBartok]
        private static bool useLinkedStack;

        [System.Diagnostics.Conditional("DEBUG")]
        static unsafe void StartupChecks() {
            VTable v = ((RuntimeType)typeof(System.VTable)).classVtable;
            Assert(v.depth == (Constants.TypeTestDisplayObjectOffset + 1),
                   "Depth of VTable's VTable is wrong, so either the hierarchy " +
                   "has changed or the compiler and runtime differ over the " +
                   "size of the display so the depth offset is wrong");
            fixed(int * p =  &v.depth) {
                UIntPtr up = (UIntPtr) p;
                UIntPtr upBase = Magic.addressOf(v);
                int diff = ((int) (up - upBase)) / UIntPtr.Size;
#if (REFERENCE_COUNTING_GC || DEFERRED_REFERENCE_COUNTING_GC)
                Assert(diff == Constants.TypeTestDisplaySize + 3,
                       "Number of display fields does not match constant");
#else // REFERENCE_COUNTING_GC
                Assert(diff == Constants.TypeTestDisplaySize + 2,
                       "Number of display fields does not match constant");
#endif
            }
        }

        static unsafe VTable() {
            StartupChecks();

            // Ensure that the monitors have been allocated, so that we don't
            // try to allocate them just as we are running out of memory
            Monitor.Enter(VTable.cctorLock);
            Monitor.Exit(VTable.cctorLock);
        }

        internal static void checkNonNull(object obj) {
            if (obj == null) {
                throw new NullReferenceException();
            }
        }

        [Inline]
        [RequiredByBartok]
        internal static void checkUnbox(object obj, int structuralType) {
            if (structuralType != (int) obj.vtable.structuralView) {
#if SINGULARITY
                Tracing.Log(Tracing.Debug, "checkUnbox failed: Obj={0:x8} st={1}",
                            Magic.addressOf(obj),
                            unchecked((uint)structuralType));
#endif

                throwNewClassCastException();
            }
        }

#if (REFERENCE_COUNTING_GC || DEFERRED_REFERENCE_COUNTING_GC)
        // The CheckVectorStore opcode returns a value to model a
        // dependency with respect to StoreVectorElement.
        // CheckVectorStore gets lowered to a call to checkArrayStore.
        // If the call is subsequently inlined, the type checker may
        // complain, due to effects like t := Id<ArraySafetyCheck>().
        //
        // The bug shows up in release builds with the RC collector,
        // when the RCCollectorOptInlineRCUpdates stage-control is
        // also turned on.
        //
        // Attaching [NoInline] to checkArrayStore is a temporary
        // solution to get around this bug.
        [NoInline]
#endif // REFERENCE_COUNTING_GC
        [RequiredByBartok]
        internal static void checkArrayStore(object obj1,object obj2) {
            Assert(obj1.vtable.vtableType.IsArray);

            // can't put an object into a primitive array, but we can probably
            // guarantee that this is never called on a primitive type array
            VTable obj1VT = obj1.vtable;
            VTable obj1ElemVT = obj1VT.arrayElementClass;
            RuntimeType obj1ElemTy = obj1ElemVT.vtableType;

            // typeof is too slow right now...
            //if(obj1ElemTy == typeof(Object)) {
            //    return;
            //}

            Deny(obj1ElemTy.IsPrimitive);

            if(obj2 == null) {
                return;
            }

            RuntimeType obj2Ty = obj2.vtable.vtableType;
            if(! isValidAssignment(obj1ElemTy, obj2Ty)) {
#if SINGULARITY
                Tracing.Log(Tracing.Debug,
                            "checkArrayStore failed: obj1={0:x8} obj2={1:x8} obj1ElemTy={2:x8} obj2Ty={3:x8}",
                            Magic.addressOf(obj1),
                            Magic.addressOf(obj2),
                            Magic.addressOf(obj1ElemTy),
                            Magic.addressOf(obj2Ty));
#endif
                throwNewArrayTypeMismatchException();
            }
        }

        [RequiredByBartok]
        internal static void checkArrayElementAddress(RuntimeType ty,
                                                      object obj) {
            if(ty != obj.vtable.vtableType) {
                throwNewArrayTypeMismatchException();
#if SINGULARITY
                Tracing.Log(Tracing.Debug,
                            "checkArrayElementAddress failed: ty={0:x8} obj={1:x8}",
                            Magic.addressOf(ty),
                            Magic.addressOf(obj));
#endif
            }
        }

        [NoBarriers]
        [PreInitRefCounts]
        private static bool isValidAssignmentArray(RuntimeType ty,
                                                   RuntimeType objTy) {
            Assert((ty.IsVector && objTy.IsVector) ||
                   (ty.IsRectangleArray && objTy.IsRectangleArray),
                   "incompatible arrays");
            Assert(ty.classVtable.arrayOf == objTy.classVtable.arrayOf,
                   "!= arrayOfs");

            VTable tyVT = ty.classVtable;
            VTable tyElementVT = tyVT.arrayElementClass;
            Assert(tyElementVT != null, "array has null arrayElementClass");
            RuntimeType tyElementType = tyElementVT.vtableType;
            RuntimeType objElementType =
                objTy.classVtable.arrayElementClass.vtableType;

            // struct
            if(tyVT.arrayOf == StructuralType.Struct) {
                return tyElementType == objElementType;
            }

            // primitives and enums -- this allows int[], E1[], and E2[]
            // to cast either way (assuming E1 and E2 are based on int)
            if(tyVT.arrayOf != StructuralType.Reference) {
                return true;
            }

            // reference
            return isValidAssignment(tyElementType, objElementType);
        }

        [NoBarriers]
        [PreInitRefCounts]
        internal static bool isValidAssignment(RuntimeType ty,RuntimeType objTy) {
            return (ty == objTy) || isValidAssignmentMedium(ty, objTy);
        }

        [NoBarriers]
        [PreInitRefCounts]
        internal static bool isValidAssignmentMedium(RuntimeType ty,
                                                     RuntimeType objTy)
        {
            RuntimeType testType = objTy;
            do {
                testType = testType.baseType;
                if (ty == testType) {
                    return true;
                }
            } while (testType != null);
            return isValidAssignmentSlow(ty, objTy);
        }

        [NoBarriers]
        [PreInitRefCounts]
        private static bool isValidAssignmentSlow(RuntimeType ty,
                                                  RuntimeType objTy)
        {
            Assert(ty != null, "isValidAssignment null dst type");
            Assert(objTy != null, "isValidAssignment null src type");

            if(ty.classVtable.arrayOf != StructuralType.None) {
                // ty is an Array
                if(ty.classVtable.arrayOf == objTy.classVtable.arrayOf) {
                    if(ty.IsVector) {
                        if (objTy.IsVector) {
                            return isValidAssignmentArray(ty, objTy);
                        }
                    } else {
                        Assert(ty.IsRectangleArray, "not rectangle array");
                        if(!objTy.IsVector && ty.rank == objTy.rank) {
                            return isValidAssignmentArray(ty, objTy);
                        }
                    }
                }
            } else if ((ty.attributes & TypeAttributes.ClassSemanticsMask) ==
                       TypeAttributes.Interface) {
                // ty is an Interface
                System.RuntimeType[] interfaces = objTy.interfaces;
                if(interfaces != null) {
                    int numInterfaces = interfaces.Length;
                    for(int i=0; i<numInterfaces; ++i) {
                        if(interfaces[i] == ty) {
                            return true;
                        }
                    }
                }
            }
            return false;
        }

        [RequiredByBartok]
        internal static Object isInstanceOf(RuntimeType ty,object obj) {
            if(obj == null) {
                return null;
            }
            RuntimeType objTy = obj.vtable.vtableType;
            if(isValidAssignment(ty, objTy)) {
                return obj;
            } else {
                return null;
            }
        }

        // null ok
        [RequiredByBartok]
        [NoBarriers]
        [PreInitRefCounts]
        internal static void checkClassCast(RuntimeType ty,object obj) {
            if(obj != null && !isValidAssignment(ty, obj.vtable.vtableType)) {
#if SINGULARITY
                Tracing.Log(Tracing.Debug,
                            "checkClassCast failed: ty={0:x8} obj={1:x8}",
                            Magic.addressOf(ty),
                            Magic.addressOf(obj));
#endif
                throwNewClassCastException();
            }
        }

        // "Simple" means that we must be testing against a type that is in our
        // display.  Deep classes, interfaces, and arrays of interfaces are not
        // simple.  "Exact" means that we do not accept subtypes.  This is
        // common if we are testing against a sealed type since it will have no
        // subtypes.
#if OLD_FAST_TESTS
        // The boolean parameters should always be inlined constants -- it is here
        // so that the callers here in VTable can be partially evaluated at
        // compile-time.
        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        internal unsafe static bool newIsValidAssignment(VTable vtarget,
                                                         VTable vobj,
                                                         int vtargetDepth,
                                                         bool alwaysExact,
                                                         bool alwaysSimple) {
            Assert((int)vtarget.depth == vtargetDepth);
            Assert(vtargetDepth > 0);

            if(alwaysExact) {
                return vobj == vtarget;
            }

            UIntPtr * p = (UIntPtr *) Magic.addressOf(vobj);

#if (REFERENCE_COUNTING_GC || DEFERRED_REFERENCE_COUNTING_GC)
            if(alwaysSimple ||
               (vtargetDepth < Constants.TypeTestDisplayPosCache)) {
                return p[vtargetDepth+1] == Magic.addressOf(vtarget);
            }
#else // REFERENCE_COUNTING_GC
            if(alwaysSimple ||
               (vtargetDepth < Constants.TypeTestDisplayPosCache)) {
                return p[vtargetDepth] == Magic.addressOf(vtarget);
            }
#endif

#if (REFERENCE_COUNTING_GC || DEFERRED_REFERENCE_COUNTING_GC)
            if(p[vtargetDepth+1] == Magic.addressOf(vtarget)) {
                return true;
            }
#else // REFERENCE_COUNTING_GC
            if(p[vtargetDepth] == Magic.addressOf(vtarget)) {
                return true;
            }
#endif

            if(isValidAssignment(vtarget.vtableType, vobj.vtableType)) {
                vobj.posCache = vtarget;
                return true;
            }

            return false;
        }

        [Inline]
        private static Object newIsInstanceOf(VTable v,
                                              Object obj,
                                              int vtargetDepth,
                                              bool mayBeNull,
                                              bool mustBeExact,
                                              bool alwaysSimple) {
            if(mayBeNull && obj == null) {
                return null;
            }

            VTable objVtable = obj.vtable;
            if(newIsValidAssignment(v, objVtable, vtargetDepth, mustBeExact,
                                    alwaysSimple)) {
                return obj;
            } else {
                return null;
            }
        }

        [Inline]
        [RequiredByBartok]
        internal static Object newIsInstanceOfNonNullExact(VTable v,
                                                           Object obj,
                                                           int vtargetDepth) {
            return newIsInstanceOf(v, obj, vtargetDepth, false, true, true);
        }

        [Inline]
        [RequiredByBartok]
        internal static Object newIsInstanceOfExact(VTable v,
                                                    Object obj,
                                                    int vtargetDepth) {
            return newIsInstanceOf(v, obj, vtargetDepth, true, true, true);
        }

        [Inline]
        [RequiredByBartok]
        internal static Object newIsInstanceOfNonNullSimple(VTable v,
                                                            Object obj,
                                                            int vtargetDepth) {
            return newIsInstanceOf(v, obj, vtargetDepth, false, false, true);
        }

        [Inline]
        [RequiredByBartok]
        internal static Object newIsInstanceOfSimple(VTable v,
                                                     Object obj,
                                                     int vtargetDepth) {
            return newIsInstanceOf(v, obj, vtargetDepth, true, false, true);
        }

        [Inline]
        [RequiredByBartok]
        internal static Object newIsInstanceOfNonNullComplex(VTable v,
                                                             Object obj,
                                                             int vtargetDepth) {
            return newIsInstanceOf(v, obj, vtargetDepth, false, false, false);
        }

        [Inline]
        [RequiredByBartok]
        internal static Object newIsInstanceOfComplex(VTable v,
                                                      Object obj,
                                                      int vtargetDepth) {
            return newIsInstanceOf(v, obj, vtargetDepth, true, false, false);
        }

        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        internal static void newCheckClassCast(VTable v,
                                               object obj,
                                               int vtargetDepth,
                                               bool mayBeNull,
                                               bool mustBeExact,
                                               bool alwaysSimple) {
            if(mayBeNull && obj == null) {
                return;
            }
            if(!newIsValidAssignment(v, obj.vtable, vtargetDepth, mustBeExact,
                                     alwaysSimple)) {
#if SINGULARITY
                Tracing.Log(Tracing.Debug,
                            "newCheckClassCast failed: v={0:x8} obj={1:x8} vtd={2} mbn={3} as={4}",
                            Magic.addressOf(v),
                            Magic.addressOf(obj),
                            unchecked((uint)vtargetDepth),
                            unchecked((uint)(mayBeNull ? 1 : 0)),
                            unchecked((uint)(alwaysSimple ? 1 : 0)));
#endif
                throwNewClassCastException();
            }
        }

        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        [RequiredByBartok]
        internal static void newCheckClassCastNonNullExact(VTable v,
                                                           object obj,
                                                           int vtargetDepth) {
            newCheckClassCast(v, obj, vtargetDepth, false, true, true);
        }

        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        [RequiredByBartok]
        internal static void newCheckClassCastExact(VTable v,
                                                    object obj,
                                                    int vtargetDepth) {
            newCheckClassCast(v, obj, vtargetDepth, true, true, true);
        }

        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        [RequiredByBartok]
        internal static void newCheckClassCastNonNullSimple(VTable v,
                                                            object obj,
                                                            int vtargetDepth) {
            newCheckClassCast(v, obj, vtargetDepth, false, false, true);
        }

        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        [RequiredByBartok]
        internal static void newCheckClassCastSimple(VTable v,
                                                     object obj,
                                                     int vtargetDepth) {
            newCheckClassCast(v, obj, vtargetDepth, true, false, true);
        }

        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        [RequiredByBartok]
        internal static void newCheckClassCastNonNullComplex(VTable v,
                                                             object obj,
                                                             int vtargetDepth)
        {
            newCheckClassCast(v, obj, vtargetDepth, false, false, false);
        }

        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        [RequiredByBartok]
        internal static void newCheckClassCastComplex(VTable v,
                                                      object obj,
                                                      int vtargetDepth) {
            newCheckClassCast(v, obj, vtargetDepth, true, false, false);
        }

#else

        [Inline]
        private unsafe static bool checkDisplay(VTable vtarget,
                                                VTable vobj,
                                                int vtargetDepth) {
            UIntPtr * p = (UIntPtr *) Magic.addressOf(vobj);
            Assert((int)vtarget.depth == vtargetDepth);
            Assert(vtargetDepth > 0);

#if (REFERENCE_COUNTING_GC || DEFERRED_REFERENCE_COUNTING_GC)
            return p[vtargetDepth+1] == Magic.addressOf(vtarget);
#else // REFERENCE_COUNTING_GC
            return p[vtargetDepth] == Magic.addressOf(vtarget);
#endif
        }

        [Inline]
        [RequiredByBartok]
        internal static Object newIsInstanceOfNonNullSimple(VTable v,
                                                            Object obj,
                                                            int vtargetDepth) {
            return checkDisplay(v, obj.vtable, vtargetDepth)
                ? obj : null;
        }

        [Inline]
        internal static Object newIsInstanceOfSimple(VTable v,
                                                     Object obj,
                                                     int vtargetDepth) {
            if(obj == null) {
                return null;
            }
            return newIsInstanceOfNonNullSimple(v, obj, vtargetDepth);
        }

        [NoInline]
        internal static Object newIsInstanceOfHelp(VTable v,
                                                   Object obj) {
            int vtargetDepth = v.depth;
            if(vtargetDepth < Constants.TypeTestDisplayPosCache) {
                return null;
            }

            VTable vobj = obj.vtable;

            if(isValidAssignment(v.vtableType, vobj.vtableType)) {
                v.posCache = vobj;
                return obj;
            }

            return null;
        }

        [Inline]
        [RequiredByBartok]
        internal static Object newIsInstanceOfNonNullComplex(VTable v,
                                                             Object obj,
                                                             int vtargetDepth) {

            return checkDisplay(v, obj.vtable, vtargetDepth)
                ? obj : newIsInstanceOfHelp(v, obj);
        }

        [Inline]
        internal static Object newIsInstanceOfComplex(VTable v,
                                                      Object obj,
                                                      int vtargetDepth) {
            if(obj == null) {
                return null;
            }
            return newIsInstanceOfNonNullComplex(v, obj, vtargetDepth);
        }

        [Inline]
        [RequiredByBartok]
        internal static void newCheckClassCastNonNullSimple(VTable v,
                                                            object obj,
                                                            int vtargetDepth) {
            if(!checkDisplay(v, obj.vtable, vtargetDepth)) {
#if SINGULARITY
                Tracing.Log(Tracing.Debug,
                            "newCheckClassCastNonNullSimple failed: v={0:x8} obj={1:x8} vtd={2}",
                            Magic.addressOf(v),
                            Magic.addressOf(obj),
                            unchecked((uint)vtargetDepth));
#endif
                throwNewClassCastException();
            }
        }

        [Inline]
        [NoBarriers]
        [PreInitRefCounts]
        [RequiredByBartok]
        internal static void newCheckClassCastSimple(VTable v,
                                                     object obj,
                                                     int vtargetDepth) {
            if(obj == null) {
                return;
            }
            newCheckClassCastNonNullSimple(v, obj, vtargetDepth);
        }

        [NoInline]
        [NoBarriers]
        [PreInitRefCounts]
        internal static void newCheckClassCastHelp(VTable v,
                                                   VTable vobj) {
            int vtargetDepth = v.depth;
            if(vtargetDepth == Constants.TypeTestDisplayPosCache
               && isValidAssignment(v.vtableType, vobj.vtableType)) {
                v.posCache = vobj;
                return;
            }

#if SINGULARITY
            Tracing.Log(Tracing.Debug,
                        "newCheckClassCastHelp failed: v={0:x8} vobj={1:x8}",
                        Magic.addressOf(v),
                        Magic.addressOf(vobj));
#endif
            throwNewClassCastException();
        }

        [Inline]
        [RequiredByBartok]
        internal static void newCheckClassCastNonNullComplex(VTable v,
                                                             object obj,
                                                             int vtargetDepth) {
            VTable vobj = obj.vtable;
            if(!checkDisplay(v, vobj, vtargetDepth)) {
                newCheckClassCastHelp(v, vobj);
            }
        }

        [Inline]
        [RequiredByBartok]
        internal static void newCheckClassCastComplex(VTable v,
                                                      object obj,
                                                      int vtargetDepth) {
            if(obj == null) {
                return;
            }
            newCheckClassCastNonNullComplex(v, obj, vtargetDepth);
        }

        /*
          [NoInline]
          internal static void newCheckArrayStoreHelp(VTable v,
          VTable vobj) {
          int vtargetDepth = v.depth;
          if(vtargetDepth == Constants.TypeTestDisplayPosCache
          && isValidAssignment(v.vtableType, vobj.vtableType)) {
          v.posCache = vobj;
          return;
          }

          throwNewArrayTypeMismatchException();
          }

          [NoInline]
          internal static void newCheckArrayStore(object obj1,object obj2) {
          Assert(obj1.vtable.vtableType.IsArray);

          if(obj2 == null) {
          return;
          }

          // can't put an object into a primitive array, but we can probably
          // guarantee that this is never called on a primitive type array
          VTable obj1ElemTy = obj1.vtable.arrayElementClass;
          VTable obj2Ty = obj2.vtable;

          Deny(obj1ElemTy.vtableType.IsPrimitive);

          if(checkDisplay(obj1ElemTy, obj2Ty, obj1ElemTy.depth)) {
          return;
          }

          newCheckArrayStoreHelp(obj1ElemTy, obj2Ty);
          }
        */
#endif // OLD_FAST_TESTS

        [NoInline]
        internal static bool shouldDoCallTrace() {
            return VTable.runtimeInitialized && !VTable.callTraceInProgress;
        }

        [NoInline]
        internal static void callTrace(Object o) {
            if(o == null) {
                VTable.DebugPrint("null");
                return;
            }

            VTable.callTraceInProgress = true;
            try {
                VTable.DebugPrint(o.ToString());
            } catch(Exception) {
                VTable.DebugPrint("exn");
            }
            VTable.callTraceInProgress = false;
        }

        // Bartok intrinsics

        [Intrinsic]
        internal static extern ulong mulUIntUIntToULong(uint x, uint y);

        internal static extern bool BuildC2Mods
        {
            [Intrinsic]
            get;
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        private static void initTypePrint(RuntimeType ty, String s)
        {
            if (VTable.enableDebugPrint) {
#if ALLOW_BOOT_ARGLIST
                DebugPrint("initType({0}.{1}): {2}\n",
                           __arglist(ty.Namespace, ty.Name, s));
#endif
            }
        }

        [NoBarriers]
        [PreInitRefCounts]
        internal static void InitializeLimitedType(Type t)
        {
            InitializeLimitedType(Magic.toRuntimeType(t));
        }

        [NoBarriers]
        [PreInitRefCounts]
        private static void InitializeLimitedType(RuntimeType ty)
        {
#if SINGULARITY_KERNEL
            Tracing.Log(Tracing.Debug, "InitializeLimitedType({0}.{1}",
                        ty.Namespace, ty.Name);
            //DebugStub.WriteLine("InitializeLimitedType({0}.{1})",
            //__arglist(ty.Namespace, ty.Name));
#endif

            // Null check is needed because Bartok can remove static type
            // constructors and we don't have a good framework for removing the
            // static initialization of those types (particularly in
            // VTable.Initialize).
            if(ty.cctor != UIntPtr.Zero) {
                Magic.calli(ty.cctor);
            }
            ty.cctorState = TypeInitState.Completed;
        }

        // Rationale for cutting the fact that no stack probes are permitted in this
        // tree of calls:
        //
        // There is no legitimate rationale.  A bug exists in the database for all
        // intractable violations, listing each one including this one.  This violation
        // is somewhat intractable because initType requires a link check and yet it
        // is potentially called from stack linking code that cannot tolerate any
        // linking.
        //
        // We need to rethink the .NET model for implicit lazy class initialization,
        // since it is hard to reason about the failure points.
        //
        // Bug 436
        [NoStackLinkCheckTransCut]
        [RequiredByBartok]
        [CalledRarely]
        internal static void initType(RuntimeType ty) {
            // Abort early if the type has already been initialized.
            if (ty.cctorState == TypeInitState.Completed) {
                return;
            }
            // Or if it doesn't have a class constructor.
            if (ty.cctor == UIntPtr.Zero) {
                ty.cctorState = TypeInitState.Completed;
                return;
            }

#if SINGULARITY_KERNEL
            if (!multiThreaded) {
                //DebugStub.WriteLine("initType({0}.{1}) - singlethreaded",
                //__arglist(ty.Namespace, ty.Name));
                switch(ty.cctorState) {
                    case TypeInitState.Ready:
                        initTypePrint(ty, "ready");
                        ty.cctorState = TypeInitState.Running;

                        try {
                            initTypePrint(ty, "running");
                            Magic.calli(ty.cctor);
                        } catch (Exception e) {
                            initTypePrint(ty, "failed");

                            // Wrap the type initializer exception
                            // appropriately and save it for future calls.

                            ty.cctorState = TypeInitState.Failed;
                            Exception exn
                                = new TypeInitializationException(ty.FullName, e);
                            ty.cctorException = exn;
                            throw exn;
                        }
                        initTypePrint(ty, "complete");
                        ty.cctorState = TypeInitState.Completed;
                        return;

                    case TypeInitState.Failed:
                        initTypePrint(ty, "previous failure");
                        throw ty.cctorException;

                    case TypeInitState.Completed:
                        initTypePrint(ty, "already completed");
                        return;

                    default:
                        initTypePrint(ty, "selfloop or finished");

                        if (ty.cctorState == TypeInitState.Failed) {
                            initTypePrint(ty, "clash finished - failed");

                            throw ty.cctorException;
                        }
                        return;
                }
            }
            //DebugStub.WriteLine("initType({0}.{1}) - multithreaded",
            //__arglist(ty.Namespace, ty.Name));
#endif

            // Get global lock - must have to read/write any thread/type
            // wait dependencies.  Also used for some things that possibly
            // should be shifted to the type locks.

            // BUGBUG: The local lock used below is the RuntimeType object.  We
            // can't use VTable since interfaces do not currently have VTable
            // objects.  But RuntimeType is exposed to users and thus this is
            // incorrect.
            Monitor.Enter(VTable.cctorLock);

            switch(ty.cctorState) {
                case TypeInitState.Ready:{
                    initTypePrint(ty, "ready");

                    // Record that this thread is running this type initializer.

                    Thread t = Thread.CurrentThread;
                    ty.cctorThread = t;
                    ty.cctorState = TypeInitState.Running;

                    // Get local lock - must have to actually run an initializer
                    // and thus also to check if one is done.  We are done setting
                    // global state and ready to run the local (type) initializer;
                    // therefore we can dump the global lock now as well.

                    lock (ty) { // .classVtable) {
                        Monitor.Exit(VTable.cctorLock);
                        // we don't need to start with "initialize base and
                        // all interfaces" because the compiler explicitly
                        // add calls to the base and interfaces ..ctor in
                        // current type's ..cctor.

                        // Run the type initializer, if it exists.
                        if (ty.cctor != UIntPtr.Zero) {
                            try {
                                initTypePrint(ty, "running");
                                Magic.calli(ty.cctor);
                            } catch(Exception e) {
                                initTypePrint(ty, "failed");

                                // Wrap the type initializer exception
                                // appropriately and save it for future calls.

                                ty.cctorState = TypeInitState.Failed;
                                ty.cctorThread = null;
                                Exception exn = new TypeInitializationException
                                    (ty.FullName, e);
                                ty.cctorException = exn;
                                throw exn;
                            }
                        }
                        initTypePrint(ty, "complete");
                        ty.cctorState = TypeInitState.Completed;
                        ty.cctorThread = null;
                    }

                    return;
                }

                case TypeInitState.Running:{
                    initTypePrint(ty, "clash");

                    // Try to grab the local lock.  This seems somewhat confusing
                    // to me but I'll follow the CLR code for now (see
                    // VM\class.cpp:EEClass::DoRunClassInit()).  It is important
                    // to do the TryEnter() as we need to detect circular
                    // dependencies.

                    Thread runningThread = ty.cctorThread;
                    bool gotIt = Monitor.TryEnter(ty); // .classVtable);
                    if (gotIt) {
                        initTypePrint(ty, "selfloop or finished");

                        // If we succeed in getting the lock, then either the
                        // class finished between the switch statement and here
                        // (setting complete/fail does not require the global
                        // lock...) or this thread is attempting circular
                        // initialization.  In the former we need to check for
                        // success/failure; in the latter we just return to
                        // prevent deadlock (state will still be Running and thus
                        // not Failed).

                        Monitor.Exit(ty); // .classVtable);
                        Monitor.Exit(VTable.cctorLock);

                        if (ty.cctorState == TypeInitState.Failed) {
                            initTypePrint(ty, "clash finished - failed");

                            throw ty.cctorException;
                        }
                        return;
                    } else {
                        initTypePrint(ty, "blocked by another thread");

                        // Check and see if blocking this thread to wait for the
                        // type to complete initialization will cause a deadlock.
                        // To do this, see which thread is initializing the type
                        // and then follow the blocking threads.  This thread
                        // can not be at any of the intermediate (next blocking
                        // thread is non-null) points as by definition they are
                        // blocked and can't have reached here.

                        Thread currentThread = Thread.CurrentThread;
                        Thread blockingThread = runningThread;
                        VTable.Assert(blockingThread != null);

                        while(blockingThread.blockingCctorThread != null) {
                            blockingThread = blockingThread.blockingCctorThread;
                        }

                        if(currentThread == blockingThread) {

                            // Circular dependency.  Give up on "finished
                            // initialization" guaranties and just return.

                            initTypePrint(ty, "circular");
                            Monitor.Exit(VTable.cctorLock);
                            return;
                        }

                        // Set us as blocked by this type, release the global
                        // lock, and wait for the type to complete initialization.
                        // REVIEW: I have concerns about the lack of lock around
                        // setting the block to null.  Come back to this!

                        currentThread.blockingCctorThread = runningThread;
                        Monitor.Exit(VTable.cctorLock);
                        lock (ty) {} // .classVtable) {}
                        currentThread.blockingCctorThread = null;

                        // The type has finished initialization.  As above, the
                        // two possible cases are Completed and Failed.

                        if(ty.cctorState == TypeInitState.Failed) {
                            throw ty.cctorException;
                        }
                        return;
                    }
                }

                case TypeInitState.Failed:
                    initTypePrint(ty, "previous failure");
                    Monitor.Exit(VTable.cctorLock);
                    throw ty.cctorException;

                case TypeInitState.Completed:
                    initTypePrint(ty, "already completed");
                    Monitor.Exit(VTable.cctorLock);
                    return;
            }
        }

        [NoStackLinkCheckTransCut]
        [NoInline]
        internal static void throwNewClassCastException() {
            throw new InvalidCastException();
        }

        [NoInline]
        internal static void throwNewArgumentOutOfRangeException() {
            throw new ArgumentOutOfRangeException();
        }

        // Rationale for cutting the fact that no stack probes are permitted in this
        // tree of calls:
        //
        // Without this, then trees of code that cannot probe (like the stack link and
        // unlink code itself) cannot use arrays.  This is too high a burden.  Instead,
        // we change it to the *unchecked* requirement that this code cannot attempt to
        // over-index an array.  There is a bug that captures the fact that we cannot
        // check this behavior.
        //
        // Bug 436
        [NoStackLinkCheckTransCut]
        [NoInline]
        [RequiredByBartok]
        internal static void throwNewIndexOutOfRangeException() {
            throw new IndexOutOfRangeException();
        }

        [NoInline]
        [RequiredByBartok]
        internal static void throwNewStringIndexOutOfRangeException() {
            throw new ArgumentOutOfRangeException();
        }

        [NoInline]
        internal static void throwNewArrayTypeMismatchException() {
            throw new ArrayTypeMismatchException();
        }

        // Rationale for cutting the fact that no stack probes are permitted in this
        // tree of calls:
        //
        // Without this, then trees of code that cannot probe (like the stack link and
        // unlink code itself) cannot use arrays.  This is too high a burden.  Instead,
        // we change it to the *unchecked* requirement that this code cannot attempt to
        // over-index an array.  There is a bug that captures the fact that we cannot
        // check this behavior.
        //
        // Bug 436
        [NoStackLinkCheckTransCut]
        [NoInline]
        [AccessedByRuntime("referenced from halasm.asm")]
        internal static void throwNewOverflowException() {
#if DEBUG && SINGULARITY
            DebugStub.WriteLine("Overflow exception");
            DebugStub.Break();
#endif
            throw new OverflowException();
        }

        // Rationale for cutting the fact that no stack probes are permitted in this
        // tree of calls:
        //
        // Without this, then trees of code that cannot probe (like the stack link and
        // unlink code itself) cannot use arrays.  This is too high a burden.  Instead,
        // we change it to the *unchecked* requirement that this code cannot attempt to
        // over-index an array.  There is a bug that captures the fact that we cannot
        // check this behavior.
        //
        // Bug 436
        [NoStackLinkCheckTransCut]
        [NoInline]
        [RequiredByBartok]
        internal static void throwNewDivideByZeroException() {
            throw new DivideByZeroException();
        }

        [NoStackLinkCheckTransCut]
        [NoInline]
        [RequiredByBartok]
        internal static void throwNewArithmeticException() {
            throw new ArithmeticException();
        }

        [System.Diagnostics.Conditional("DEBUG")]
        // Rationale for cutting the fact that no stack probes are permitted in this
        // tree of calls:
        //
        // This is DEBUG-only code.  It is reachable from every interface call, which
        // means we would have to effectively prevent usage of interface calls when
        // stack probes are transitively forbidden.  This is a needless burden for
        // DEBUG-only code.
        [NoStackLinkCheckTransCut]
        [StackLinkCheck]
        private static void profileInterfaceOffset(VTable v, RuntimeType ty,
                                                   int index) {
            // REVIEW: Counts could be off in a multithreaded setting, but these
            // are just debug counts and if extra hashtables are allocated or
            // increments are missed it's not that big of a deal.

            // index ignored

            if(VTable.runtimeInitialized && VTable.enableDumpInterface) {
                if(VTable.interfaceOffsetTable == null) {
                    VTable.interfaceOffsetTable =
                        new System.Collections.Hashtable();
                }

                System.Collections.Hashtable h = (System.Collections.Hashtable)
                    VTable.interfaceOffsetTable[v];
                if(h == null) {
                    VTable.interfaceOffsetTable[v] = h =
                        new System.Collections.Hashtable();
                }

                MutableInt32 m = (MutableInt32) h[ty];

                if(m == null) {
                    h[ty] = new MutableInt32(1);
                } else {
                    m.Value++;
                }
            }
        }

        [DisableBoundsChecks]
        [RequiredByBartok]
        internal static IntPtr interfaceOffset(VTable v,RuntimeType ty) {
            InterfaceInfo[] interfaces = v.interfaces;
            VTable.Assert(interfaces != null);
            int numInterfaces = interfaces.Length;
            int i;
            for(i=0; i<numInterfaces; ++i) {
                if(interfaces[i].type == ty) {
                    break;
                }
            }

            profileInterfaceOffset(v, ty, i);

            VTable.Assert(i != numInterfaces);

            return interfaces[i].offset;
        }

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(24)]
        [RequiredByBartok]
        internal static extern int doubleToInt(double d);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(28)]
        [RequiredByBartok]
        internal static extern long doubleToLong(double d);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(20)]
        [RequiredByBartok]
        internal static extern int floatToInt(float f);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(24)]
        [RequiredByBartok]
        internal static extern long floatToLong(float  f);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(24)]
        [RequiredByBartok]
        internal static extern int checkedDoubleToInt(double d);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(28)]
        [RequiredByBartok]
        internal static extern long checkedDoubleToLong(double d);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(20)]
        [RequiredByBartok]
        internal static extern int checkedFloatToInt(float f);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(24)]
        [RequiredByBartok]
        internal static extern long checkedFloatToLong(float  f);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(12)]
        [RequiredByBartok]
        internal static extern float floatRem(float f1, float f2);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [GCAnnotation(GCOption.NOGC)]
        [StackBound(20)]
        [RequiredByBartok]
        internal static extern double doubleRem(double d1, double d2);

        // mulSigned64Bit: signed 2's complement 64-bit multiplication with
        // overflow checking.
        //
        // x,y and the result are represented in 2's complement.  The
        // following algorithm is used:
        //   Compute the sign of x*y.
        //   Compute |x| * |y| using unsigned arithmetic
        //   If the sign of the result is non-negative
        //       Check that x*y <= 2^(n-1)-1.
        //   If the sign of the result is negative,
        //       Check that x*y <= 2^(n-1).
        //       Convert back to 2's complement:
        //          2^n - x*y
        [RequiredByBartok]
        static public long mulOverflowSigned64Bit(long x,long y) {
            bool isPositive = true;
            if (x < 0) {
                x = -x;
                isPositive = false;
            }
            if (y < 0) {
                y = -y;
                isPositive = !isPositive;
            }
            ulong result = mulOverflowUnsigned64Bit((ulong) x, (ulong) y);
            if (isPositive) {
                if (result <= 0x7FFFFFFFFFFFFFFF) {
                    return (long) result;
                } else {
                    VTable.throwNewOverflowException();
                    return 0;
                }
            } else {
                if (result <= 0x8000000000000000) {
                    return -((long) result);
                } else {
                    VTable.throwNewOverflowException();
                    return 0;
                }
            }
        }

        [RequiredByBartok]
        // unsigned 64-bit multiplication with overflow checking
        static public ulong mulOverflowUnsigned64Bit(ulong x,ulong y) {
            uint loX = (uint) x;
            uint hiX = (uint) (x >> 32);
            uint loY = (uint) y;
            uint hiY = (uint) (y >> 32);
            if (hiX > 0 && hiY > 0) {
                VTable.throwNewOverflowException();
            }
            ulong result = mulUIntUIntToULong(loY, loX);
            checked {
                result =  result + (((ulong) (loX * hiY)) << 32);
                result =  result + (((ulong) (loY * hiX)) << 32);
            }
            return result;
        }

        [RequiredByBartok]
        // unsigned 64-bit multiplication with no overflow checking
        static public ulong mulUnsigned64Bit(ulong x,ulong y) {
            uint loX = (uint) x;
            uint hiX = (uint) (x >> 32);
            uint loY = (uint) y;
            uint hiY = (uint) (y >> 32);
            ulong result = mulUIntUIntToULong(loY, loX);
            result =  result + (((ulong) (loX * hiY)) << 32);
            result =  result + (((ulong) (loY * hiX)) << 32);
            return result;
        }

        [RequiredByBartok]
        static public ulong doubleToULong(double val) {
            double two63 = 2147483648.0 * 4294967296.0;
            ulong ret;
            if (val < two63) {
                ret = (ulong)doubleToLong(val);
            } else {
                // subtract 0x8000000000000000, do the convert then add
                // it back again
                ret = (ulong)doubleToLong(val - two63) + (0x8000000000000000L);
            }
            return ret;
        }

        [RequiredByBartok]
        static public ulong checkedDoubleToULong(double val) {
            double two64  = 4294967296.0 * 4294967296.0;
            // Note that this expression also works properly for val = NaN case
            if (val > -1.0 && val < two64) {
                const double two63  = 2147483648.0 * 4294967296.0;
                ulong ret;
                if (val < two63) {
                    ret = (ulong)doubleToLong(val);
                } else {
                    // subtract 0x8000000000000000, do the convert then add
                    // it back again
                    ret = (ulong)doubleToLong(val - two63) + (0x8000000000000000L);
                }
                return ret;
            }
            // throw
            VTable.throwNewOverflowException();
            return 0;
        }

        public const bool enableLibraryOptions = true;
        internal static bool enableDebugPrint = false; /*true to log initType calls*/
        internal static bool enableUserTiming = false;
        internal static bool enableGCVerify = false;
        internal static bool enableGCProfiling = false;
        internal static bool enableGCTiming = false;
        internal static bool enableFinalGCTiming = false;
        internal static bool enableGCAccounting = false;
        internal static bool enableGCAccurateHeapSize = false;
        internal static bool enableDumpMemStats = false;
        internal static bool enableDumpMultiUseWords = false;
        internal static bool enableDumpInterface = false;
        internal static bool enableDumpTryAllStats = false;

        internal static int beforeUser;
        internal static int afterUser;

        [NoHeapAllocation]
        public static bool EnableLibraryNotImplemented() {
            return(false);
        }

        [NoHeapAllocation]
        public static bool EnableLibraryAsserts() {
            return(true);
        }

        [NoHeapAllocation]
        public static void NotImplemented() {
            failAssert("Not implemented.");
        }

        [NoHeapAllocation]
        public static void NotImplemented(String msg) {
            failAssert(/*"Not implemented: "+*/msg);
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        [NoHeapAllocation]
        public static void NotReached() {
            failAssert("Unreachable code reached.");
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        [NoHeapAllocation]
        public static void NotReached(String msg) {
            failAssert(/*"Unreachable code reached: "+*/msg);
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        [ManualRefCounts]
        [NoHeapAllocation]
        [NoStackLinkCheckTrans]
        public static void Assert(bool expr) {
            if (VTable.enableLibraryOptions && EnableLibraryAsserts() && !expr) {
                failAssert(null);
            }
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        [ManualRefCounts]
        [NoHeapAllocation]
        [NoStackLinkCheckTrans]
        public static void Deny(bool expr) {
            if (VTable.enableLibraryOptions && EnableLibraryAsserts() && expr) {
                failAssert(null);
            }
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        [NoHeapAllocation]
        public static void AssertForRedundant(bool expr) {
            if (!expr) {
                failAssert(null);
            }
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        [NoHeapAllocation]
        public static void DenyForRedundant(bool expr) {
            AssertForRedundant(!expr);
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        [ManualRefCounts]
        [NoHeapAllocation]
        public static void Assert(bool expr, String s) {
            if (VTable.enableLibraryOptions && EnableLibraryAsserts() && !expr) {
                failAssert(s);
            }
        }

        [System.Diagnostics.Conditional("DEBUG")]
        [NoInline]
        [NoHeapAllocation]
        public static void Deny(bool expr, String s) {
            if (VTable.enableLibraryOptions && EnableLibraryAsserts() && expr) {
                failAssert(s);
            }
        }

        // Rationale for cutting the fact that no stack probes are permitted in this
        // tree of calls:
        //
        // * Asserts are debug only.
        // * When an assert fails, a future stack overflow is not our biggest problem.
        // * We want the ability to freely assert in trees that forbid stack probes.
        [NoStackLinkCheckTransCut]
        [ManualRefCounts]
        [NoHeapAllocation]
        private static void failAssert(String s) {
#if SINGULARITY
            if (s != null) {
                Tracing.Log(Tracing.Notice, "Assertion failed: {0}\n", s);
            } else {
                Tracing.Log(Tracing.Notice, "Assertion failed\n");
            }
#endif
            //        DebugPrintSpinLock();
            //        DebugPrint(Thread.currentThread().toString());
            if (s != null) {
                DebugPrint("Assertion failed: {0}\n", __arglist(s));
            }
            else {
                DebugPrint("Assertion failed.\n");
            }
            //        Thread.DebugDumpThreadAnchorTable(0);
            DebugBreak();
            //        DebugPrintSpinUnlock();
        }

#if SINGULARITY_KERNEL || SINGULARITY_PROCESS

        // Note confusion: This DebugPrint is an unconditional output to stderr,
        // not something that only prints in BRT debug modes.
        [RequiredByBartok]
        [NoHeapAllocation]
        static public void DebugPrint(String v)
        {
            DebugStub.Print(v);
        }

        [NoHeapAllocation]
        static public void DebugPrint(String v, __arglist)
        {
            DebugStub.Print(v, new ArgIterator(__arglist));
        }

        [NoHeapAllocation]
        static public void DebugPrint(String v, ArgIterator args)
        {
            DebugStub.Print(v, args);
        }

        [RequiredByBartok]
        static public void DebugPrint(int v)
        {
            DebugStub.Print("{0}", __arglist(v));
        }

        [RequiredByBartok]
        static public void DebugPrint(long v)
        {
            DebugStub.Print("{0}", __arglist(v));
        }

        [NoHeapAllocation]
        static public void DebugBreak()
        {
            DebugStub.Break();
        }

#else // not SINGULARITY

        // Note confusion: This DebugPrint is an unconditional output to stderr,
        // not something that only prints in BRT debug modes.
        [RequiredByBartok]
        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(312)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugPrint(String v);

        [MethodImpl(MethodImplOptions.InternalCall)]
        //[StackBound(610)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static private unsafe extern void DebugPrintHelper(char *p_str, int length);

        const int DEBUG_MESSAGE_BUFFER_SIZE = 4095;
        [NoHeapAllocation]
        static public unsafe void DebugPrint(String v, ArgIterator args)
        {
            char *memBuffer = stackalloc char[DEBUG_MESSAGE_BUFFER_SIZE+1];
            // note that we save 1 for the null character
            int stringLength = String.LimitedFormatTo(v, args, memBuffer, DEBUG_MESSAGE_BUFFER_SIZE);
            VTable.Assert(stringLength <= DEBUG_MESSAGE_BUFFER_SIZE, "String.LimitedFormatTo returned an impossibly large stringLength");
            // null terminate the string
            DebugPrintHelper(memBuffer, stringLength);
        }

        [NoHeapAllocation]
        static public void DebugPrint(String v, __arglist)
        {
            DebugPrint(v, new ArgIterator(__arglist));
        }

        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(610)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugPrint(byte v);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(610)]
        [RequiredByBartok]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugPrint(int v);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(618)]
        [RequiredByBartok]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugPrint(long v);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(618)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugPrint(ulong v);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(618)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugPrint(int v, int width);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(626)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugPrint(long v, int width);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugPrint(ulong v, int width);

        [NoHeapAllocation]
        static public void DebugPrint(bool b)
        {
            if (b) {
                DebugPrint("true");
            }
            else {
                DebugPrint("false");
            }
        }

        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(638)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugDump(object o);

        [MethodImpl(MethodImplOptions.InternalCall)]
        [StackBound(638)]
        [NoHeapAllocation]
        [GCAnnotation(GCOption.NOGC)]
        static public extern void DebugBreak();

#endif

        [AccessedByRuntime("referenced from halexn.cpp")]
        [NoHeapAllocation]
        static public bool IsExceptionHandler(Type t,Exception e) {
            Type s = e.vtable.vtableType;
            // check whether s is a subtype of t
            do {
                if (s==t) {
                    return true;
                }
                s = s.BaseType;
            } while (s != null);
            return false;
        }

#if SINGULARITY
        static public String[] ParseArgs(String[] args)
#else
        [AccessedByRuntime("referenced from brtmain.cpp")]
        static public String[] ParseArgs()
#endif
        {
#if !SINGULARITY
            String[] args = System.Environment.GetCommandLineArgs();
#endif

            int i=0;

#if !SINGULARITY_KERNEL
            ++i;  // dump program name argument
#endif

            for( ; i<args.Length; ++i) {
                String arg = args[i];
                if(!arg.StartsWith("--brt")) {
                    break;
                }

                if(arg == "--brt-debug") {
                    VTable.enableDebugPrint = true;
                    continue;
                }

#if !SINGULARITY
                if(arg == "--brt-one-cpu") {
                    Thread.SetOneCPU();
                    continue;
                }
#endif

                if(arg == "--brt-user-timing") {
                    VTable.enableUserTiming = true;
                    beforeUser = Environment.TickCount;
                    continue;
                }

                if(arg == "--brt-stw-retrace") {
                    GC.enableSTWRetrace = true;
                    continue;
                }

                if(arg == "--brt-gc-verify") {
                    VTable.enableGCVerify = true;
                    continue;
                }

                if(arg == "--brt-gc-profiling") {
                    VTable.enableGCProfiling = true;
                    continue;
                }

                if(arg == "--brt-gc-timing") {
                    VTable.enableGCTiming = true;
                    continue;
                }

                if(arg == "--brt-final-gc-timing") {
                    VTable.enableFinalGCTiming = true;
                    continue;
                }

                if(arg == "--brt-gc-accounting") {
                    VTable.enableGCAccounting = true;
                    continue;
                }

                if(arg == "--brt-gc-heapsize") {
                    VTable.enableGCAccurateHeapSize = true;
                    continue;
                }

                if(arg == "--brt-dump-memstats") {
                    VTable.enableDumpMemStats = true;
                    continue;
                }

                if(arg == "--brt-dump-muw") {
                    VTable.enableDumpMultiUseWords = true;
                    continue;
                }

                if(arg == "--brt-dump-interface") {
                    VTable.enableDumpInterface = true;
                    continue;
                }

                if(arg == "--brt-tryallchecksize") {
                    ++i;
                    if(i==args.Length) {
                        DebugPrint
                            ("--brt-tryallchecksize requires argument\r\n");
                        DebugBreak();
                    }

                    try {
                        int tryAllSize = Int32.Parse(args[i]);

                        // check that it's a power of two
                        VTable.Assert
                            ((tryAllSize > 0)
                             && (((tryAllSize - 1) & tryAllSize) == 0),
                             "--brt-tryallchecksize must be a power of two");
                        VTable.tryAllCheckMask = tryAllSize - 1;
                    } catch(FormatException) {
                        DebugPrint
                            ("--brt-tryallchecksize requires argument\r\n");
                        DebugBreak();
                    }
                    continue;
                }

                if(arg == "--brt-dump-tryallstats") {
                    VTable.enableDumpTryAllStats = true;
                    continue;
                }

                if(arg == "--brt-countgc-trigger") {
#if !SINGULARITY || ADAPTIVE_COPYING_COLLECTOR || SEMISPACE_COLLECTOR
                    switch(GC.gcType) {
                      case GCType.AdaptiveCopyingCollector:
                      case GCType.SemispaceCollector: {
                          ++i;
                          if(i==args.Length) {
                              DebugPrint("--brt-countgc-trigger requires argument\r\n");
                              DebugBreak();
                          }

                          try {
                              short countGCTrigger = Int16.Parse(args[i]);
                              if(countGCTrigger == -1) {
                                  countGCTrigger = Int16.MaxValue;
                              }
                              GCs.GenerationalGCData.gcFrequencyTable
                                    [(int)GCs.GenerationalGCData.MIN_GENERATION] = countGCTrigger;
                          } catch(FormatException) {
                              DebugPrint("--brt-countgc-trigger requires argument\r\n");
                              DebugBreak();
                          }
                          break;
                      }
                    }
#endif
                    continue; // argument loop
                }

                if(arg == "--brt-promotegc-trigger") {
#if !SINGULARITY || ADAPTIVE_COPYING_COLLECTOR || SEMISPACE_COLLECTOR
                    switch(GC.gcType) {
                      case GCType.AdaptiveCopyingCollector:
                      case GCType.SemispaceCollector: {
                          ++i;
                          if(i==args.Length) {
                              DebugPrint("--brt-promotegc-trigger requires argument\r\n");
                              DebugBreak();
                          }

                          try {
                              long promotedGCTrigger = Int64.Parse(args[i]);
                              if(promotedGCTrigger == -1L) {
                                  promotedGCTrigger = Int64.MaxValue;
                              }
                              GCs.GenerationalGCData.gcPromotedLimitTable
                                 [(int)GCs.GenerationalGCData.MIN_GENERATION] = (UIntPtr) promotedGCTrigger;
                          } catch(FormatException) {
                              DebugPrint
                                  ("--brt-promotegc-trigger requires argument\r\n");
                              DebugBreak();
                          }
                          break;
                      }
                    }
#endif
                    continue; // argument loop
                }

                if(arg == "--brt-nurserysize") {
#if !SINGULARITY || ADAPTIVE_COPYING_COLLECTOR || SEMISPACE_COLLECTOR
                    switch(GC.gcType) {
                      case GCType.AdaptiveCopyingCollector:
                      case GCType.SemispaceCollector: {
                          ++i;
                          if(i==args.Length) {
                              DebugPrint
                                  ("--brt-nurserysize requires argument\r\n");
                              DebugBreak();
                          }

                          try {
                              GCs.GenerationalGCData.nurserySize = (UIntPtr)
                                  UInt64.Parse(args[i]);
                          } catch(FormatException) {
                              DebugPrint("--brt-nurserysize-trigger requires argument\r\n");
                              DebugBreak();
                          }
                          break;
                      }
                    }
#endif
                    continue; // argument loop
                }

                if(arg == "--brt-maxheapsizekb") {
                    Assert(GC.HeapSizeConfigurable,
                           "not compiled with /heapsizeconfigurable");

                    ++i;
                    if(i==args.Length) {
                       DebugPrint
                           ("--brt-maxheapsizekb requires argument\r\n");
                       DebugBreak();
                    }

                    try {
                        int maxheapsizekb = Int32.Parse(args[i]);
                        GC.MaxHeapPages =
                            maxheapsizekb >>
                            (GCs.PageTable.PageBits-10);
                    } catch(FormatException) {
                        DebugPrint("--brt-maxheapsizekb requires argument\r\n");
                        DebugBreak();
                    }
                    continue; // argument loop
                }

                /*
                if(arg == "--brt-ssbsize") {
                    ++i;
                    if(i==args.Length) {
                        DebugPrint
                            ("--brt-ssbsize requires argument\r\n");
                        DebugBreak();
                    }

                    try {
                        SequentialStoreBuffer.??? = Int32.Parse(args[i]);
                    } catch(FormatException) {
                        DebugPrint
                            ("--brt-ssbsize requires argument\r\n");
                        DebugBreak();
                    }
                    continue;
                }
                */

                if(arg == "--brt-gctrace-filter") {
                    ++i;
                    if(i==args.Length) {
                        DebugPrint
                            ("--brt-gctrace-filter requires argument\r\n");
                        DebugBreak();
                    }

                    try {
                        System.GCs.Trace.filter = (UIntPtr)
                            UInt64.Parse(args[i], System.Globalization.NumberStyles.AllowHexSpecifier);
                    } catch(FormatException) {
                        DebugPrint
                            ("--brt-gctrace-filter requires a hex argument\r\n");
                        DebugBreak();
                    }
                    continue;
                }

                if(arg == "--brt-gctrace-filter-range") {
                    i += 2;
                    if(i >= args.Length) {
                        DebugPrint
                            ("--brt-gctrace-filter-range requires two hex arguments\r\n");
                        DebugBreak();
                    }

                    try {
                        System.GCs.Trace.filterLow = (UIntPtr)
                            UInt64.Parse(args[i-1], System.Globalization.NumberStyles.AllowHexSpecifier);
                        System.GCs.Trace.filterHigh = (UIntPtr)
                            UInt64.Parse(args[i], System.Globalization.NumberStyles.AllowHexSpecifier);
                    } catch(FormatException) {
                        DebugPrint
                            ("--brt-gctrace-filter-range requires two hex arguments\r\n");
                        DebugBreak();
                    }
                    continue;
                }

                if(arg == "--brt-gctrace-filter-area") {
                    ++i;
                    if(i >= args.Length) {
                        DebugPrint
                            ("--brt-gctrace-filter-area requires hex argument\r\n");
                        DebugBreak();
                    }

                    try {
                        System.GCs.Trace.filterArea = (System.GCs.Trace.Area)
                            Int32.Parse(args[i], System.Globalization.NumberStyles.AllowHexSpecifier);
                    } catch(FormatException) {
                        DebugPrint
                            ("--brt-gctrace-filter-area requires hex argument\r\n");
                        DebugBreak();
                    }
                    continue;
                }

                DebugPrint("Unrecognized BRT option: {0}\n", __arglist(arg));
                DebugBreak();
            }

            if(VTable.enableGCAccounting) {
                GCs.MemoryAccounting.Initialize(GC.gcType);
            }

            int mainArgsLength = args.Length - i;
            VTable.Assert(mainArgsLength >= 0,
                          "negative number of args to Main");
            String[] mainArgs = new String[mainArgsLength];

            for(int j=0; i<args.Length; ++i, ++j) {
                mainArgs[j] = args[i];
            }

            return mainArgs;
        }

        // This method is modified by Bartok.
        // It calls profiling dump functions.
        [RequiredByBartok]
        [NoInline]
        private static void Shutdown() {}

        // REVIEW: We need to make sure that this is called for all exit modes.
        // Right now we have normal exit, exception exit, and Environment.Exit,
        // but we probably want an OS hook.  Also, nothing important to
        // shutdown happens here anyway.

#if SINGULARITY
        private static int hasShutdownStarted = 0;
#endif

#if !SINGULARITY
        [AccessedByRuntime("Referenced from brtmain.cpp")]
#endif
        static public void Shutdown(int exitCode) {
            if (fDebug) {
                VTable.DebugPrint("shutdown called with exitCode = ");
                VTable.DebugPrint(exitCode);
                VTable.DebugPrint("\n");
            }

            if (VTable.enableUserTiming) {
                int afterUser = Environment.TickCount;
                VTable.DebugPrint("wall-clock time spent in user code = ");
                VTable.DebugPrint(afterUser-beforeUser);
                VTable.DebugPrint("\n");
            }

            GC.Shutdown();

#if SINGULARITY_KERNEL
            if (Interlocked.CompareExchange(ref hasShutdownStarted, 1, 0) != 0) {
                return;
            }
            Kernel.Shutdown(exitCode);
#elif SINGULARITY_PROCESS
            if (Interlocked.CompareExchange(ref hasShutdownStarted, 1, 0) != 0) {
                return;
            }
            Finalizer.Shutdown();
#else
            if(Interlocked.CompareExchange(ref Environment.hasShutdownStarted,
                                           1, 0) != 0) {
                return;
            }
            Finalizer.Shutdown();
#endif

            VTable.Shutdown();

            if(VTable.enableDumpMultiUseWords) {
                MultiUseWord.DumpTables();
            }

            if(VTable.enableDumpInterface) {
                if(VTable.interfaceOffsetTable != null) {
                    foreach(System.Collections.DictionaryEntry d
                            in VTable.interfaceOffsetTable) {
                        VTable v = (VTable) d.Key;
                        foreach(System.Collections.DictionaryEntry d2
                                in (System.Collections.Hashtable) d.Value) {
                            RuntimeType ty = (RuntimeType) d2.Key;
                            MutableInt32 m = (MutableInt32) d2.Value;
                            int num = m.Value;

                            IntPtr index = interfaceOffset(v, ty);

                            DebugPrint("{0} - {1}: {2}\n",
                                       __arglist(v.vtableType.FullName,
                                                 ty.FullName,
                                                 num));
                        }
                    }
                }
            }

#if !VC
            if(VTable.enableDumpTryAllStats) {
                TryAllCounters.DumpRegisteredCounters();
            }
#endif

            int size = handle_counts.Length;
            if(size > 4) {
                for(int i = 0; i < size; i++) {
                    if(handle_counts[i] == 0) {
                        continue;
                    }
                    DebugPrint("{0:d3}: {1}\n", __arglist(i, handle_counts[i]));
                }
            }
            GC.DestructHeap();
        }

        [AccessedByRuntime("referenced from halexn.cpp")]
        static public void TerminateByException(Exception e) {
            RuntimeType rt = (RuntimeType)e.GetType();
            DebugPrint("\n");
            DebugPrint("Unhandled Exception ({0}.{1}):\n",
                       __arglist(rt.Namespace, rt.Name));
            DebugPrint("  {0}\n", __arglist(e.Message));
            try {
                DebugPrint("  {0}\n", __arglist(e.ToString()));
            } catch(Exception) {
                try {
                    DebugPrint("\n   Exception.ToString() failed.\n");
                } catch (Exception) {
                }
            } finally {
                Shutdown(-2);
            }
            DebugBreak();
        }

        static public void DumpException(Exception e) {
            RuntimeType rt = (RuntimeType)e.GetType();
            DebugPrint("Handled Exception ({0}.{1}):\n",
                       __arglist(rt.Namespace, rt.Name));
            DebugPrint("  {0}\n", __arglist(e.Message));
            try {
                DebugPrint("  {0}\n", __arglist(e.ToString()));
            } catch(Exception) {
                try {
                    DebugPrint("   Exception.ToString() failed.\n");
                } catch (Exception) {
                }
            } finally {
            }
        }

        [RequiredByBartok]
        public static void init(object obj) {
        }

        private static bool fDebug { get { return false; } }

    }
}