Opentk/Source/Generator.Rewrite/Program.cs
thefiddler 18ef634610 [Build] Fixed ErrorHelper local variable
We need to emit a ldloca instruction before constructing the
ErrorHelper instance, in order to reference it in the finally
block below.
2014-02-25 01:08:53 +01:00

797 lines
33 KiB
C#

// OpenTK.Rewrite: IL rewriter for OpenTK.dll
// Copyright (C) 2013 Stefanos Apostolopoulos
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using Mono.Cecil;
using Mono.Cecil.Cil;
using Mono.Cecil.Rocks;
namespace OpenTK.Rewrite
{
// Replaces OpenTK.InteropHelper method instances
// with the s IL instructions.
class Program
{
static void Main(string[] args)
{
if (args.Length == 0)
{
Console.WriteLine("Usage: rewrite [file.dll] [file.snk] [options]");
Console.WriteLine("[options] is:");
Console.WriteLine(" -debug (enable calls to GL.GetError())");
return;
}
var program = new Program();
var file = args[0];
var key = args[1];
var options = args.Where(a => a.StartsWith("-") || a.StartsWith("/"));
program.Rewrite(file, key, options);
}
// mscorlib types
static AssemblyDefinition mscorlib;
static TypeDefinition TypeMarshal;
static TypeDefinition TypeStringArray;
static TypeDefinition TypeStringBuilder;
static TypeDefinition TypeVoid;
static TypeDefinition TypeIntPtr;
// OpenTK.BindingsBase
static TypeDefinition TypeBindingsBase;
void Rewrite(string file, string keyfile, IEnumerable<string> options)
{
// Specify assembly read and write parameters
// We want to keep a valid symbols file (pdb or mdb)
var read_params = new ReaderParameters();
var write_params = new WriterParameters();
var pdb = Path.ChangeExtension(file, "pdb");
var mdb = Path.ChangeExtension(file, "mdb");
ISymbolReaderProvider provider = null;
if (File.Exists(pdb))
{
provider = new Mono.Cecil.Pdb.PdbReaderProvider();
}
else if (File.Exists(mdb))
{
provider = new Mono.Cecil.Mdb.MdbReaderProvider();
}
read_params.SymbolReaderProvider = provider;
read_params.ReadSymbols = true;
write_params.WriteSymbols = true;
if (!String.IsNullOrEmpty(keyfile) && File.Exists(keyfile))
{
keyfile = Path.GetFullPath(keyfile);
var fs = new FileStream(keyfile, FileMode.Open);
var keypair = new System.Reflection.StrongNameKeyPair(fs);
fs.Close();
write_params.StrongNameKeyPair = keypair;
}
else
{
Console.Error.WriteLine("No keyfile specified or keyfile missing.");
}
// Load assembly and process all modules
var assembly = AssemblyDefinition.ReadAssembly(file, read_params);
var rewritten = assembly.CustomAttributes.FirstOrDefault(a => a.AttributeType.Name == "RewrittenAttribute");
if (rewritten == null)
{
foreach (var module in assembly.Modules)
{
foreach (var reference in module.AssemblyReferences)
{
var resolved = module.AssemblyResolver.Resolve(reference);
if (reference.Name == "mscorlib")
{
mscorlib = resolved;
}
}
}
if (mscorlib == null)
{
Console.Error.WriteLine("Failed to locate mscorlib");
return;
}
TypeMarshal = mscorlib.MainModule.GetType("System.Runtime.InteropServices.Marshal");
TypeStringArray = mscorlib.MainModule.GetType("System.String").MakeArrayType().Resolve();
TypeStringBuilder = mscorlib.MainModule.GetType("System.Text.StringBuilder");
TypeVoid = mscorlib.MainModule.GetType("System.Void");
TypeIntPtr = mscorlib.MainModule.GetType("System.IntPtr");
TypeBindingsBase = assembly.Modules.Select(m => m.GetType("OpenTK.BindingsBase")).First();
foreach (var module in assembly.Modules)
{
foreach (var type in module.Types)
{
Rewrite(type, options);
}
}
}
else
{
Console.Error.WriteLine("Error: assembly has already been rewritten");
}
// Save rewritten assembly
assembly.Write(file, write_params);
}
void Rewrite(TypeDefinition type, IEnumerable<string> options)
{
var entry_points = type.Fields.FirstOrDefault(f => f.Name == "EntryPoints");
if (entry_points != null)
{
// Build list of entry point signatures (one per entry point)
var entry_signatures = new List<MethodDefinition>();
entry_signatures.AddRange(type.Methods
.Where(t => t.CustomAttributes.Any(a => a.AttributeType.Name == "SlotAttribute")));
Rewrite(type, entry_points, entry_signatures, options);
RemoveNativeSignatures(type, entry_signatures);
}
if (type.Name == "RewrittenAttribute")
{
var rewritten_constructor = type.GetConstructors().First();
var rewritten = new CustomAttribute(rewritten_constructor);
rewritten.ConstructorArguments.Add(new CustomAttributeArgument(
type.Module.Import(mscorlib.MainModule.GetType("System.Boolean")), true));
type.Module.Assembly.CustomAttributes.Add(rewritten);
}
}
void Rewrite(TypeDefinition type, FieldDefinition entry_points,
List<MethodDefinition> entry_signatures, IEnumerable<string> options)
{
// Rewrite all wrapper methods
var wrapper_signatures = new List<MethodDefinition>();
wrapper_signatures.AddRange(type.Methods
.Where(m => m.IsPublic && m.CustomAttributes.Any(a => a.AttributeType.Name == "AutoGeneratedAttribute")));
foreach (var wrapper in wrapper_signatures)
{
var autogenerated = wrapper.CustomAttributes
.Where(a => a.AttributeType.Name == "AutoGeneratedAttribute");
if (autogenerated.Count() > 0)
{
var signature_name = (string)autogenerated.First()
.Fields.First(f => f.Name == "EntryPoint").Argument.Value;
var signature = entry_signatures.First(s => s.Name == signature_name);
var slot = (int)signature.CustomAttributes
.First(a => a.AttributeType.Name == "SlotAttribute")
.ConstructorArguments[0].Value;
ProcessMethod(wrapper, signature, slot, entry_points, options);
}
}
RemoveSupportingAttributes(type);
if (type.NestedTypes.Count > 0)
{
foreach (var nested_type in type.NestedTypes)
{
Rewrite(nested_type, entry_points, entry_signatures, options);
}
}
}
void RemoveNativeSignatures(TypeDefinition type, List<MethodDefinition> methods)
{
while (methods.Count > 0)
{
type.Methods.Remove(methods.Last());
methods.RemoveAt(methods.Count - 1);
}
}
void RemoveSupportingAttributes(TypeDefinition type)
{
foreach (var method in type.Methods)
{
var attr = method.CustomAttributes;
for (int i = 0; i < attr.Count; i++)
{
if (attr[i].AttributeType.Name == "AutoGeneratedAttribute")
{
attr.RemoveAt(i);
i--;
}
}
}
}
// Create body for method
static void ProcessMethod(MethodDefinition wrapper, MethodDefinition native, int slot,
FieldDefinition entry_points, IEnumerable<string> options)
{
var body = wrapper.Body;
var il = body.GetILProcessor();
var instructions = body.Instructions;
instructions.Clear();
// Declare pinned variables for every reference and array parameter
// and push each parameter on the stack
DebugVariables vars = null;
if (options.Contains("-debug"))
{
vars = EmitDebugPrologue(wrapper, il);
}
// Patch convenience wrappers
if (wrapper.Parameters.Count == native.Parameters.Count)
{
EmitParameters(wrapper, body, il);
}
else
{
int difference = native.Parameters.Count - wrapper.Parameters.Count;
EmitConvenienceWrapper(wrapper, native, difference, body, il);
}
// push the entry point address on the stack
EmitEntryPoint(entry_points, il, slot);
// issue calli
EmitCall(il, native);
if (wrapper.ReturnType.Name != "Void")
{
EmitReturnTypeWrapper(wrapper, native, body, il);
}
if (wrapper.Parameters.Any(p => p.ParameterType.Name == "StringBuilder"))
{
EmitStringBuilderEpilogue(wrapper, native, body, il);
}
if (wrapper.Parameters.Any(p => p.ParameterType.Name == "String" && p.ParameterType.IsArray))
{
EmitStringArrayEpilogue(wrapper, body, il);
}
if (wrapper.Parameters.Any(p => p.ParameterType.Name == "String" && !p.ParameterType.IsArray))
{
EmitStringEpilogue(wrapper, body, il);
}
if (options.Contains("-debug"))
{
EmitDebugEpilogue(wrapper, il, vars);
}
// return
il.Emit(OpCodes.Ret);
if (body.Variables.Count > 0)
{
// Required for verifiable executables
// (otherwise peverify complains bitterly)
body.InitLocals = true;
}
body.OptimizeMacros();
}
class DebugVariables
{
public TypeDefinition ErrorHelperType;
public VariableDefinition ErrorHelperLocal;
public MethodReference Get_CurrentContext;
public MethodReference Set_ErrorChecking;
public Instruction BeginTry;
}
static DebugVariables EmitDebugPrologue(MethodDefinition wrapper, ILProcessor il)
{
DebugVariables vars = null;
if (il.Body.Method.Name != "GetError")
{
// Pull out the namespace name, method fullname will look
// something like "type namespace.class::method(type arg)"
var module = il.Body.Method.FullName;
module = module.Substring(module.IndexOf(' ') + 1);
module = module.Substring(0, module.IndexOf("::"));
module = module.Substring(0, module.LastIndexOf('.'));
// Only works for Graphics modules due to hardcoded use of
// OpenTK.Graphics.GraphicsContext
if (module == "OpenTK.Graphics.OpenGL4" ||
module == "OpenTK.Graphics.OpenGL" ||
module == "OpenTK.Graphics.ES10" ||
module == "OpenTK.Graphics.ES11" ||
module == "OpenTK.Graphics.ES20" ||
module == "OpenTK.Graphics.ES30")
{
var errorHelperType = wrapper.Module.GetType(module, "ErrorHelper");
if (errorHelperType != null)
{
vars = new DebugVariables();
vars.ErrorHelperType = errorHelperType;
// GraphicsContext type
var graphicsContext = wrapper.Module.Types.First(
type => type.FullName == "OpenTK.Graphics.GraphicsContext");
// IGraphicsContext type
var iGraphicsContext = wrapper.Module.Types.First(
type => type.FullName == "OpenTK.Graphics.IGraphicsContext");
// Get the constructor that takes a GraphicsContext parameter
var ctor = vars.ErrorHelperType.GetConstructors().FirstOrDefault(
c => c.Parameters.Count == 1 &&
c.Parameters[0].ParameterType.FullName == iGraphicsContext.FullName);
if (ctor == null)
{
throw new InvalidOperationException(
String.Format(
"{0} does needs a constructor taking {1}",
errorHelperType,
graphicsContext));
}
// GraphicsContext.CurrentContext property getter
vars.Get_CurrentContext = graphicsContext.Methods.First(
method => method.Name == "get_CurrentContext");
vars.Set_ErrorChecking = graphicsContext.Methods.First(
method => method.Name == "set_ErrorChecking");
vars.ErrorHelperLocal = new VariableDefinition(vars.ErrorHelperType);
// using (new ErrorHelper(GraphicsContext.CurrentContext)) { ...
il.Body.Variables.Add(vars.ErrorHelperLocal);
il.Emit(OpCodes.Ldloca, vars.ErrorHelperLocal);
il.Emit(OpCodes.Call, vars.Get_CurrentContext);
il.Emit(OpCodes.Call, ctor);
vars.BeginTry = Instruction.Create(OpCodes.Nop);
il.Append(vars.BeginTry);
// Special case Begin to turn off error checking.
if (il.Body.Method.Name == "Begin")
{
il.Emit(OpCodes.Call, vars.Get_CurrentContext);
il.Emit(OpCodes.Ldc_I4_0);
il.Emit(OpCodes.Conv_I1);
il.Emit(OpCodes.Call, vars.Set_ErrorChecking);
}
}
}
}
return vars;
}
static void EmitDebugEpilogue(MethodDefinition wrapper, ILProcessor il, DebugVariables vars)
{
if (vars != null)
{
var disposeMethod = vars.ErrorHelperType.Methods.First(
method => method.Name == "Dispose");
// Store then reload the result from the call
var resultLocal = new VariableDefinition(wrapper.ReturnType);
if (resultLocal.VariableType.FullName != Program.TypeVoid.FullName)
{
il.Body.Variables.Add(resultLocal);
il.Emit(OpCodes.Stloc, resultLocal);
}
// Special case End to turn on error checking.
if (il.Body.Method.Name == "End")
{
il.Emit(OpCodes.Call, vars.Get_CurrentContext);
il.Emit(OpCodes.Ldc_I4_1);
il.Emit(OpCodes.Conv_I1);
il.Emit(OpCodes.Call, vars.Set_ErrorChecking);
}
// We need a NOP to set up the finally handler range correctly.
var nopInstruction = Instruction.Create(OpCodes.Nop);
var loadInstruction = Instruction.Create(OpCodes.Ldloca, vars.ErrorHelperLocal);
var disposeInstruction = Instruction.Create(OpCodes.Call, disposeMethod);
var endFinallyInstruction = Instruction.Create(OpCodes.Endfinally);
var endTryInstruction = Instruction.Create(OpCodes.Leave, nopInstruction);
il.Append(endTryInstruction);
il.Append(loadInstruction);
il.Append(disposeInstruction);
il.Append(endFinallyInstruction);
il.Append(nopInstruction);
var finallyHandler = new ExceptionHandler(ExceptionHandlerType.Finally);
finallyHandler.TryStart = vars.BeginTry;
finallyHandler.TryEnd = loadInstruction;
finallyHandler.HandlerStart = loadInstruction;
finallyHandler.HandlerEnd = nopInstruction;
il.Body.ExceptionHandlers.Add(finallyHandler);
if (resultLocal.VariableType.FullName != Program.TypeVoid.FullName)
{
il.Emit(OpCodes.Ldloc, resultLocal);
}
}
}
private static void EmitReturnTypeWrapper(MethodDefinition wrapper, MethodDefinition native, MethodBody body, ILProcessor il)
{
if (wrapper.Parameters.Count < native.Parameters.Count)
{
// Convenience wrapper. The result is stored in the last local variable
il.Emit(OpCodes.Ldloc, body.Variables.Count - 1);
}
else if (wrapper.ReturnType != native.ReturnType)
{
if (wrapper.ReturnType.Name == "String")
{
// String return-type wrapper
// return new string((sbyte*)((void*)GetString()));
var intptr_to_voidpointer = wrapper.Module.Import(mscorlib.MainModule.GetType("System.IntPtr").GetMethods()
.First(m =>
{
return
m.Name == "op_Explicit" &&
m.ReturnType.Name == "Void*";
}));
var string_constructor = wrapper.Module.Import(mscorlib.MainModule.GetType("System.String").GetConstructors()
.First(m =>
{
var p = m.Parameters;
return p.Count > 0 && p[0].ParameterType.Name == "SByte*";
}));
il.Emit(OpCodes.Call, intptr_to_voidpointer);
il.Emit(OpCodes.Newobj, string_constructor);
}
else if (wrapper.ReturnType.Resolve().IsEnum)
{
// Nothing to do
}
else
{
Console.Error.WriteLine("Return wrapper for '{1}' not implemented yet ({0})", native.Name, wrapper.ReturnType.Name);
}
}
else
{
// nothing to do, the native call leaves the return value
// on the stack and we return that unmodified to the caller.
}
}
static void EmitStringBuilderEpilogue(MethodDefinition wrapper, MethodDefinition native, MethodBody body, ILProcessor il)
{
for (int i = 0; i < wrapper.Parameters.Count; i++)
{
var p = wrapper.Parameters[i].ParameterType;
if (p.Name == "StringBuilder")
{
// void GetShaderInfoLog(..., StringBuilder foo)
// try {
// foo_sb_ptr = Marshal.AllocHGlobal(sb.Capacity + 1); -- already emitted
// glGetShaderInfoLog(..., foo_sb_ptr); -- already emitted
// MarshalPtrToStringBuilder(foo_sb_ptr, foo);
// }
// finally {
// Marshal.FreeHGlobal(foo_sb_ptr);
// }
// Make sure we have imported BindingsBase::MasrhalPtrToStringBuilder and Marshal::FreeHGlobal
var ptr_to_sb = wrapper.Module.Import(TypeBindingsBase.Methods.First(m => m.Name == "MarshalPtrToStringBuilder"));
var free_hglobal = wrapper.Module.Import(TypeMarshal.Methods.First(m => m.Name == "FreeHGlobal"));
var block = new ExceptionHandler(ExceptionHandlerType.Finally);
block.TryStart = body.Instructions[0];
var variable_name = p.Name + " _sb_ptr";
var v = body.Variables.First(m => m.Name == variable_name);
il.Emit(OpCodes.Ldloc, v.Index);
il.Emit(OpCodes.Ldarg, i);
il.Emit(OpCodes.Call, ptr_to_sb);
block.TryEnd = body.Instructions.Last();
block.HandlerStart = body.Instructions.Last();
il.Emit(OpCodes.Ldloc, v.Index);
il.Emit(OpCodes.Call, free_hglobal);
block.HandlerEnd = body.Instructions.Last();
}
}
}
static void EmitStringParameter(MethodDefinition wrapper, TypeReference p, MethodBody body, ILProcessor il)
{
// string marshaling:
// IntPtr ptr = MarshalStringToPtr(str);
// try { calli }
// finally { Marshal.FreeHGlobal(ptr); }
var marshal_str_to_ptr = wrapper.Module.Import(TypeBindingsBase.Methods.First(m => m.Name == "MarshalStringToPtr"));
// IntPtr ptr;
var variable_name = p.Name + "_string_ptr";
body.Variables.Add(new VariableDefinition(variable_name, TypeIntPtr));
int index = body.Variables.Count - 1;
// ptr = Marshal.StringToHGlobalAnsi(str);
il.Emit(OpCodes.Call, marshal_str_to_ptr);
il.Emit(OpCodes.Stloc, index);
il.Emit(OpCodes.Ldloc, index);
// The finally block will be emitted in the function epilogue
}
static void EmitStringEpilogue(MethodDefinition wrapper, MethodBody body, ILProcessor il)
{
for (int i = 0; i < wrapper.Parameters.Count; i++)
{
var p = wrapper.Parameters[i].ParameterType;
if (p.Name == "String" && !p.IsArray)
{
var free = wrapper.Module.Import(TypeBindingsBase.Methods.First(m => m.Name == "FreeStringPtr"));
// FreeStringPtr(ptr)
var variable_name = p.Name + "_string_ptr";
var v = body.Variables.First(m => m.Name == variable_name);
il.Emit(OpCodes.Ldloc, v.Index);
il.Emit(OpCodes.Call, free);
}
}
}
static void EmitStringArrayParameter(MethodDefinition wrapper, TypeReference p, MethodBody body, ILProcessor il)
{
// string[] masrhaling:
// IntPtr ptr = MarshalStringArrayToPtr(strings);
// try { calli }
// finally { UnmarshalStringArray(ptr); }
var marshal_str_array_to_ptr = wrapper.Module.Import(TypeBindingsBase.Methods.First(m => m.Name == "MarshalStringArrayToPtr"));
// IntPtr ptr;
var variable_name = p.Name + " _string_array_ptr";
body.Variables.Add(new VariableDefinition(variable_name, TypeIntPtr));
int index = body.Variables.Count - 1;
// ptr = MarshalStringArrayToPtr(strings);
il.Emit(OpCodes.Call, marshal_str_array_to_ptr);
il.Emit(OpCodes.Stloc, index);
il.Emit(OpCodes.Ldloc, index);
// The finally block will be emitted in the function epilogue
}
static void EmitStringArrayEpilogue(MethodDefinition wrapper, MethodBody body, ILProcessor il)
{
for (int i = 0; i < wrapper.Parameters.Count; i++)
{
var p = wrapper.Parameters[i].ParameterType;
if (p.Name == "String" && p.IsArray)
{
var free = wrapper.Module.Import(TypeBindingsBase.Methods.First(m => m.Name == "FreeStringArrayPtr"));
var get_length = wrapper.Module.Import(TypeStringArray.Methods.First(m => m.Name == "get_Length"));
// FreeStringArrayPtr(string_array_ptr, string_array.Length)
var variable_name = p.Name + "_string_array_ptr";
var v = body.Variables.First(m => m.Name == variable_name);
il.Emit(OpCodes.Ldloc, v.Index);
il.Emit(OpCodes.Ldarg, i);
il.Emit(OpCodes.Callvirt, get_length);
il.Emit(OpCodes.Call, free);
}
}
}
private static void EmitConvenienceWrapper(MethodDefinition wrapper,
MethodDefinition native, int difference, MethodBody body, ILProcessor il)
{
if (wrapper.Parameters.Count > 2)
{
// Todo: emit all parameters bar the last two
throw new NotImplementedException();
}
if (wrapper.ReturnType.Name != "Void")
{
if (difference == 2)
{
// Convert sized out-array/reference to return value, for example:
// void GenTextures(int n, int[] textures) -> int GenTexture()
// {
// const int n = 1;
// int buffers;
// calli GenTextures(n, &textures);
// return result;
// }
body.Variables.Add(new VariableDefinition(wrapper.ReturnType));
il.Emit(OpCodes.Ldc_I4, 1); // const int n = 1
il.Emit(OpCodes.Ldloca, body.Variables.Count - 1); // &buffers
}
else if (difference == 1)
{
// Convert unsized out-array/reference to return value, for example:
// void GetBoolean(GetPName pname, out bool data) -> bool GetBoolean(GetPName pname)
// {
// bool result;
// GetBooleanv(pname, &result);
// return result;
// }
body.Variables.Add(new VariableDefinition(wrapper.ReturnType));
EmitParameters(wrapper, body, il);
il.Emit(OpCodes.Ldloca, body.Variables.Count - 1);
}
else
{
Console.Error.WriteLine("Unknown wrapper type for ({0})", native.Name);
}
}
else
{
if (difference == 1)
{
// Convert in-array/reference to single element, for example:
// void DeleteTextures(int n, ref int textures) -> void DeleteTexture(int texture)
// {
// const int n = 1;
// calli DeleteTextures(n, &textures);
// }
il.Emit(OpCodes.Ldc_I4, 1); // const int n = 1
il.Emit(OpCodes.Ldarga, wrapper.Parameters.Last()); // &textures
}
else
{
Console.Error.WriteLine("Unknown wrapper type for ({0})", native.Name);
}
}
}
static int EmitParameters(MethodDefinition method, MethodBody body, ILProcessor il)
{
int i;
for (i = 0; i < method.Parameters.Count; i++)
{
var p = method.Module.Import(method.Parameters[i].ParameterType);
il.Emit(OpCodes.Ldarg, i);
if (p.Name == "StringBuilder")
{
// void GetShaderInfoLog(..., StringBuilder foo)
// IntPtr foo_sb_ptr;
// try {
// foo_sb_ptr = Marshal.AllocHGlobal(sb.Capacity + 1);
// glGetShaderInfoLog(..., foo_sb_ptr);
// MarshalPtrToStringBuilder(foo_sb_ptr, sb);
// }
// finally {
// Marshal.FreeHGlobal(sb_ptr);
// }
// Make sure we have imported StringBuilder::Capacity and Marshal::AllocHGlobal
var sb_get_capacity = method.Module.Import(TypeStringBuilder.Methods.First(m => m.Name == "get_Capacity"));
var alloc_hglobal = method.Module.Import(TypeMarshal.Methods.First(m => m.Name == "AllocHGlobal"));
// IntPtr ptr;
var variable_name = p.Name + " _sb_ptr";
body.Variables.Add(new VariableDefinition(variable_name, TypeIntPtr));
int index = body.Variables.Count - 1;
// ptr = Marshal.AllocHGlobal(sb.Capacity + 1);
il.Emit(OpCodes.Callvirt, sb_get_capacity);
il.Emit(OpCodes.Call, alloc_hglobal);
il.Emit(OpCodes.Stloc, index);
il.Emit(OpCodes.Ldloc, index);
// We'll emit the try-finally block in the epilogue implementation,
// because we haven't yet emitted all necessary instructions here.
}
else if (p.Name == "String" && !p.IsArray)
{
EmitStringParameter(method, p, body, il);
}
else if (p.IsByReference)
{
body.Variables.Add(new VariableDefinition(new PinnedType(p)));
var index = body.Variables.Count - 1;
il.Emit(OpCodes.Stloc, index);
il.Emit(OpCodes.Ldloc, index);
il.Emit(OpCodes.Conv_I);
}
else if (p.IsArray)
{
if (p.Name != method.Module.Import(typeof(string[])).Name)
{
// Pin the array and pass the address
// of its first element.
var element_type = p.GetElementType();
body.Variables.Add(new VariableDefinition(new PinnedType(new ByReferenceType(element_type))));
int pinned_index = body.Variables.Count - 1;
var empty = il.Create(OpCodes.Ldc_I4, 0);
var pin = il.Create(OpCodes.Ldarg, i);
var end = il.Create(OpCodes.Stloc, pinned_index);
// if (array == null) goto empty
il.Emit(OpCodes.Brfalse, empty);
// else if (array.Length != 0) goto pin
il.Emit(OpCodes.Ldarg, i);
il.Emit(OpCodes.Ldlen);
il.Emit(OpCodes.Conv_I4);
il.Emit(OpCodes.Brtrue, pin);
// empty: IntPtr ptr = IntPtr.Zero
il.Append(empty);
il.Emit(OpCodes.Conv_U);
il.Emit(OpCodes.Br, end);
// pin: &array[0]
il.Append(pin);
il.Emit(OpCodes.Ldc_I4, 0);
il.Emit(OpCodes.Ldelema, element_type);
// end: fixed (IntPtr ptr = &array[0])
il.Append(end);
il.Emit(OpCodes.Ldloc, pinned_index);
il.Emit(OpCodes.Conv_I);
}
else
{
EmitStringArrayParameter(method, p, body, il);
}
}
}
return i;
}
static void EmitEntryPoint(FieldDefinition entry_points, ILProcessor il, int slot)
{
il.Emit(OpCodes.Ldsfld, entry_points);
il.Emit(OpCodes.Ldc_I4, slot);
il.Emit(OpCodes.Ldelem_I);
}
static void EmitCall(ILProcessor il, MethodReference reference)
{
var signature = new CallSite(reference.ReturnType)
{
CallingConvention = MethodCallingConvention.StdCall,
};
foreach (var p in reference.Parameters)
{
signature.Parameters.Add(p);
}
// Since the last parameter is always the entry point address,
// we do not need any special preparation before emiting calli.
il.Emit(OpCodes.Calli, signature);
}
}
}