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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
using System;
using System.Collections;
using System.Diagnostics;
using System.Globalization;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;
namespace Microsoft.Internal
{
internal static class GenerationServices
{
// Type.GetTypeFromHandle
private static readonly MethodInfo s_typeGetTypeFromHandleMethod = typeof(Type).GetMethod("GetTypeFromHandle")!;
// typeofs are pretty expensive, so we cache them statically
private static readonly Type s_typeType = typeof(System.Type);
private static readonly Type s_stringType = typeof(string);
private static readonly Type s_charType = typeof(char);
private static readonly Type s_booleanType = typeof(bool);
private static readonly Type s_byteType = typeof(byte);
private static readonly Type s_sByteType = typeof(sbyte);
private static readonly Type s_int16Type = typeof(short);
private static readonly Type s_uInt16Type = typeof(ushort);
private static readonly Type s_int32Type = typeof(int);
private static readonly Type s_uInt32Type = typeof(uint);
private static readonly Type s_int64Type = typeof(long);
private static readonly Type s_uInt64Type = typeof(ulong);
private static readonly Type s_doubleType = typeof(double);
private static readonly Type s_singleType = typeof(float);
private static readonly Type s_iEnumerableTypeofT = typeof(System.Collections.Generic.IEnumerable<>);
private static readonly Type s_iEnumerableType = typeof(System.Collections.IEnumerable);
private static readonly MethodInfo ExceptionGetData = typeof(Exception).GetProperty("Data")!.GetGetMethod()!;
private static readonly MethodInfo DictionaryAdd = typeof(IDictionary).GetMethod("Add")!;
private static readonly ConstructorInfo ObjectCtor = typeof(object).GetConstructor(Type.EmptyTypes)!;
public static ILGenerator CreateGeneratorForPublicConstructor(this TypeBuilder typeBuilder, Type[] ctrArgumentTypes)
{
ConstructorBuilder ctorBuilder = typeBuilder.DefineConstructor(
MethodAttributes.Public,
CallingConventions.Standard,
ctrArgumentTypes);
ILGenerator ctorIL = ctorBuilder.GetILGenerator();
ctorIL.Emit(OpCodes.Ldarg_0);
ctorIL.Emit(OpCodes.Call, ObjectCtor);
return ctorIL;
}
/// Generates the code that loads the supplied value on the stack
/// This is not as simple as it seems, as different instructions need to be generated depending
/// on its type.
/// We support:
/// 1. All primitive types
/// 2. Strings
/// 3. Enums
/// 4. typeofs
/// 5. nulls
/// 6. Enumerables
/// 7. Delegates on static functions or any of the above
/// Everything else cannot be represented as literals
/// <param name="ilGenerator"></param>
/// <param name="value"></param>
public static void LoadValue(this ILGenerator ilGenerator, object? value)
{
Debug.Assert(ilGenerator != null);
//
// Get nulls out of the way - they are basically typeless, so we just load null
//
if (value == null)
{
ilGenerator.LoadNull();
return;
}
//
// Prepare for literal loading - decide whether we should box, and handle enums properly
//
Type valueType = value.GetType();
object rawValue = value;
if (valueType.IsEnum)
{
// enums are special - we need to load the underlying constant on the stack
rawValue = Convert.ChangeType(value, Enum.GetUnderlyingType(valueType), null);
valueType = rawValue.GetType();
}
//
// Generate IL depending on the valueType - this is messier than it should ever be, but sadly necessary
//
if (valueType == GenerationServices.s_stringType)
{
// we need to check for strings before enumerables, because strings are IEnumerable<char>
ilGenerator.LoadString((string)rawValue);
}
else if (GenerationServices.s_typeType.IsAssignableFrom(valueType))
{
ilGenerator.LoadTypeOf((Type)rawValue);
}
else if (GenerationServices.s_iEnumerableType.IsAssignableFrom(valueType))
{
// NOTE : strings and dictionaries are also enumerables, but we have already handled those
ilGenerator.LoadEnumerable((IEnumerable)rawValue);
}
else if (
(valueType == GenerationServices.s_charType) ||
(valueType == GenerationServices.s_booleanType) ||
(valueType == GenerationServices.s_byteType) ||
(valueType == GenerationServices.s_sByteType) ||
(valueType == GenerationServices.s_int16Type) ||
(valueType == GenerationServices.s_uInt16Type) ||
(valueType == GenerationServices.s_int32Type)
)
{
// NOTE : Everything that is 32 bit or less uses ldc.i4. We need to pass int32, even if the actual types is shorter - this is IL memory model
// direct casting to (int) won't work, because the value is boxed, thus we need to use Convert.
// Sadly, this will not work for all cases - namely large uint32 - because they can't semantically fit into 32 signed bits
// We have a special case for that next
ilGenerator.LoadInt((int)Convert.ChangeType(rawValue, typeof(int), CultureInfo.InvariantCulture));
}
else if (valueType == GenerationServices.s_uInt32Type)
{
// NOTE : This one is a bit tricky. Ldc.I4 takes an Int32 as an argument, although it really treats it as a 32bit number
// That said, some UInt32 values are larger that Int32.MaxValue, so the Convert call above will fail, which is why
// we need to treat this case individually and cast to uint, and then - unchecked - to int.
ilGenerator.LoadInt(unchecked((int)((uint)rawValue)));
}
else if (valueType == GenerationServices.s_int64Type)
{
ilGenerator.LoadLong((long)rawValue);
}
else if (valueType == GenerationServices.s_uInt64Type)
{
// NOTE : This one is a bit tricky. Ldc.I8 takes an Int64 as an argument, although it really treats it as a 64bit number
// That said, some UInt64 values are larger that Int64.MaxValue, so the direct case we use above (or Convert, for that matter)will fail, which is why
// we need to treat this case individually and cast to ulong, and then - unchecked - to long.
ilGenerator.LoadLong(unchecked((long)((ulong)rawValue)));
}
else if (valueType == GenerationServices.s_singleType)
{
ilGenerator.LoadFloat((float)rawValue);
}
else if (valueType == GenerationServices.s_doubleType)
{
ilGenerator.LoadDouble((double)rawValue);
}
else
{
throw new InvalidOperationException(
SR.Format(SR.InvalidMetadataValue, value.GetType().FullName));
}
}
/// Generates the code that adds an object to a dictionary stored in a local variable
/// <param name="ilGenerator"></param>
/// <param name="dictionary"></param>
/// <param name="key"></param>
/// <param name="value"></param>
public static void AddItemToLocalDictionary(this ILGenerator ilGenerator, LocalBuilder dictionary, object key, object value)
{
ArgumentNullException.ThrowIfNull(dictionary);
ArgumentNullException.ThrowIfNull(key);
ArgumentNullException.ThrowIfNull(value);
Debug.Assert(ilGenerator != null);
ilGenerator.Emit(OpCodes.Ldloc, dictionary);
ilGenerator.LoadValue(key);
ilGenerator.LoadValue(value);
ilGenerator.Emit(OpCodes.Callvirt, DictionaryAdd);
}
/// Generates the code that adds an object from a local variable to a dictionary also stored in a local
/// <param name="ilGenerator"></param>
/// <param name="dictionary"></param>
/// <param name="key"></param>
/// <param name="value"></param>
public static void AddLocalToLocalDictionary(this ILGenerator ilGenerator, LocalBuilder dictionary, object key, LocalBuilder value)
{
ArgumentNullException.ThrowIfNull(dictionary);
ArgumentNullException.ThrowIfNull(key);
ArgumentNullException.ThrowIfNull(value);
Debug.Assert(ilGenerator != null);
ilGenerator.Emit(OpCodes.Ldloc, dictionary);
ilGenerator.LoadValue(key);
ilGenerator.Emit(OpCodes.Ldloc, value);
ilGenerator.Emit(OpCodes.Callvirt, DictionaryAdd);
}
/// Generates the code to get the type of an object and store it in a local
/// <param name="ilGenerator"></param>
/// <param name="exception"></param>
/// <param name="dataStore"></param>
public static void GetExceptionDataAndStoreInLocal(this ILGenerator ilGenerator, LocalBuilder exception, LocalBuilder dataStore)
{
ArgumentNullException.ThrowIfNull(exception);
ArgumentNullException.ThrowIfNull(dataStore);
Debug.Assert(ilGenerator != null);
ilGenerator.Emit(OpCodes.Ldloc, exception);
ilGenerator.Emit(OpCodes.Callvirt, ExceptionGetData);
ilGenerator.Emit(OpCodes.Stloc, dataStore);
}
private static void LoadEnumerable(this ILGenerator ilGenerator, IEnumerable enumerable)
{
ArgumentNullException.ThrowIfNull(enumerable);
Debug.Assert(ilGenerator != null);
// We load enumerable as an array - this is the most compact and efficient way of representing it
Type elementType;
if (ReflectionServices.TryGetGenericInterfaceType(enumerable.GetType(), GenerationServices.s_iEnumerableTypeofT, out Type? closedType))
{
elementType = closedType.GetGenericArguments()[0];
}
else
{
elementType = typeof(object);
}
//
// elem[] array = new elem[<enumerable.Count()>]
//
Type generatedArrayType = elementType.MakeArrayType();
LocalBuilder generatedArrayLocal = ilGenerator.DeclareLocal(generatedArrayType);
ilGenerator.LoadInt(enumerable.Cast<object>().Count());
ilGenerator.Emit(OpCodes.Newarr, elementType);
ilGenerator.Emit(OpCodes.Stloc, generatedArrayLocal);
int index = 0;
foreach (object? value in enumerable)
{
//
//array[<index>] = value;
//
ilGenerator.Emit(OpCodes.Ldloc, generatedArrayLocal);
ilGenerator.LoadInt(index);
ilGenerator.LoadValue(value);
if (GenerationServices.IsBoxingRequiredForValue(value) && !elementType.IsValueType)
{
ilGenerator.Emit(OpCodes.Box, value!.GetType());
}
ilGenerator.Emit(OpCodes.Stelem, elementType);
index++;
}
ilGenerator.Emit(OpCodes.Ldloc, generatedArrayLocal);
}
private static bool IsBoxingRequiredForValue(object? value)
{
if (value == null)
{
return false;
}
else
{
return value.GetType().IsValueType;
}
}
private static void LoadNull(this ILGenerator ilGenerator)
{
ilGenerator.Emit(OpCodes.Ldnull);
}
private static void LoadString(this ILGenerator ilGenerator, string s)
{
Debug.Assert(ilGenerator != null);
if (s == null)
{
ilGenerator.LoadNull();
}
else
{
ilGenerator.Emit(OpCodes.Ldstr, s);
}
}
private static void LoadInt(this ILGenerator ilGenerator, int value)
{
Debug.Assert(ilGenerator != null);
ilGenerator.Emit(OpCodes.Ldc_I4, value);
}
private static void LoadLong(this ILGenerator ilGenerator, long value)
{
Debug.Assert(ilGenerator != null);
ilGenerator.Emit(OpCodes.Ldc_I8, value);
}
private static void LoadFloat(this ILGenerator ilGenerator, float value)
{
Debug.Assert(ilGenerator != null);
ilGenerator.Emit(OpCodes.Ldc_R4, value);
}
private static void LoadDouble(this ILGenerator ilGenerator, double value)
{
Debug.Assert(ilGenerator != null);
ilGenerator.Emit(OpCodes.Ldc_R8, value);
}
private static void LoadTypeOf(this ILGenerator ilGenerator, Type type)
{
Debug.Assert(ilGenerator != null);
//typeofs() translate into ldtoken and Type::GetTypeFromHandle call
ilGenerator.Emit(OpCodes.Ldtoken, type);
ilGenerator.EmitCall(OpCodes.Call, GenerationServices.s_typeGetTypeFromHandleMethod, null);
}
}
}
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