Extract CIL opcodes and makes relation chibias-cil opcode naming both Reflection.Emit and Cecil.

opcodegen.cs

using System;
using System.Linq;

namespace ConsoleApp1;

class Program
{
    static void GenerateReflectionEmit()
    {
        var emitOpCodes =
            typeof(System.Reflection.Emit.OpCodes).GetFields().
                Where(field => field is
                {
                    IsPublic: true, IsStatic: true, IsInitOnly: true,
                    FieldType.FullName: "System.Reflection.Emit.OpCode"
                }).
                Select(field => (fieldName: field.Name, opCode: (System.Reflection.Emit.OpCode)field.GetValue(null)!)).
                Where(entry => entry.opCode.OpCodeType != System.Reflection.Emit.OpCodeType.Nternal).
                OrderBy(entry => entry.opCode.Value).
                Select(entry => (entry.fieldName, name: entry.opCode.Name!.Replace('_', '.').TrimEnd('.').ToLowerInvariant())).
                ToArray();

        Console.WriteLine("namespace chibicc.toolchain.Internal;");
        Console.WriteLine();
        Console.WriteLine("internal static class ReflectionEmitDefinition");
        Console.WriteLine("{");

        Console.WriteLine("    public static System.Collections.Generic.Dictionary<string, System.Reflection.Emit.OpCode> GetOpCodes() =>");
        Console.WriteLine("        new(System.StringComparer.OrdinalIgnoreCase)");
        Console.WriteLine("    {");

        foreach (var entry in emitOpCodes)
        {
            Console.WriteLine(
                $"        {{ \"{entry.name}\", System.Reflection.Emit.OpCodes.{entry.fieldName} }},");
        }

        Console.WriteLine("    };");
        Console.WriteLine("}");
    }

    static void GenerateCecil()
    {
        var emitOpCodeBytes =
            typeof(System.Reflection.Emit.OpCodes).GetFields().
                Where(field => field is
                {
                    IsPublic: true, IsStatic: true, IsInitOnly: true,
                    FieldType.FullName: "System.Reflection.Emit.OpCode"
                }).
                Select(field => (fieldName: field.Name, opCode: (System.Reflection.Emit.OpCode)field.GetValue(null)!)).
                Where(entry => entry.opCode.OpCodeType != System.Reflection.Emit.OpCodeType.Nternal).
                ToDictionary(
                    entry => entry.opCode.Value,
                    entry => (entry.fieldName, name: entry.opCode.Name!.Replace('_', '.').TrimEnd('.').ToLowerInvariant()));

        var cecilOpCodes = typeof(Mono.Cecil.Cil.OpCodes).GetFields().
            Where(field =>
                field.IsPublic && field.IsStatic && field.IsInitOnly &&
                field.FieldType.FullName == "Mono.Cecil.Cil.OpCode").
            Select(field =>
            {
                var opCode = (Mono.Cecil.Cil.OpCode)field.GetValue(null)!;
                if (emitOpCodeBytes.TryGetValue(opCode.Value, out var entry))
                {
                    return (fieldName: field.Name, opCode, name: entry.name);
                }
                else
                {
                    return (null!, default, null!);
                }
            }).
            Where(entry => entry.name != null && entry.opCode.OpCodeType != Mono.Cecil.Cil.OpCodeType.Nternal).
            OrderBy(entry => entry.opCode.Value).
            Select(entry => (entry.fieldName, name: entry.name)).
            ToArray();

        Console.WriteLine("namespace chibild.Internal;");
        Console.WriteLine();
        Console.WriteLine("internal static class CecilDefinition");
        Console.WriteLine("{");

        Console.WriteLine("    public static System.Collections.Generic.Dictionary<string, Mono.Cecil.Cil.OpCode> GetOpCodes() =>");
        Console.WriteLine("        new(System.StringComparer.OrdinalIgnoreCase)");
        Console.WriteLine("    {");

        foreach (var entry in cecilOpCodes)
        {
            Console.WriteLine(
                $"        {{ \"{entry.name}\", Mono.Cecil.Cil.OpCodes.{entry.fieldName} }},");
        }

        Console.WriteLine("    };");
        Console.WriteLine("}");
        
    }

    static void Main(string[] args)
    {
        GenerateReflectionEmit();
        GenerateCecil();
    }
}