//
// EmitContext.cs
//
// Author:
// Miguel de Icaza (miguel@novell.com)
// Jb Evain (jbevain@novell.com)
//
// (C) 2008 Novell, Inc. (http://www.novell.com)
//
// Permission is hereby granted, free of charge, to any person obtaining
// a copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to
// permit persons to whom the Software is furnished to do so, subject to
// the following conditions:
//
// The above copyright notice and this permission notice shall be
// included in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
//
using System;
using System.Collections.ObjectModel;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.CompilerServices;
namespace System.Linq.Expressions{
class CompilationContext {
class ParameterReplacer : ExpressionTransformer {
CompilationContext context;
ExecutionScope scope;
object [] locals;
public ParameterReplacer (CompilationContext context, ExecutionScope scope, object [] locals)
{
this.context = context;
this.scope = scope;
this.locals = locals;
}
protected override Expression VisitParameter (ParameterExpression parameter)
{
var scope = this.scope;
var locals = this.locals;
while (scope != null) {
int position = IndexOfHoistedLocal (scope, parameter);
if (position != -1)
return ReadHoistedLocalFromArray (locals, position);
locals = scope.Locals;
scope = scope.Parent;
}
return parameter;
}
Expression ReadHoistedLocalFromArray (object [] locals, int position)
{
return Expression.Field (
Expression.Convert (
Expression.ArrayIndex (
Expression.Constant (locals),
Expression.Constant (position)),
locals [position].GetType ()),
"Value");
}
int IndexOfHoistedLocal (ExecutionScope scope, ParameterExpression parameter)
{
return context.units [scope.compilation_unit].IndexOfHoistedLocal (parameter);
}
}
class HoistedVariableDetector : ExpressionVisitor {
Dictionary<ParameterExpression, LambdaExpression> parameter_to_lambda =
new Dictionary<ParameterExpression, LambdaExpression> ();
Dictionary<LambdaExpression, List<ParameterExpression>> hoisted_map;
LambdaExpression lambda;
public Dictionary<LambdaExpression, List<ParameterExpression>> Process (LambdaExpression lambda)
{
Visit (lambda);
return hoisted_map;
}
protected override void VisitLambda (LambdaExpression lambda)
{
this.lambda = lambda;
foreach (var parameter in lambda.Parameters)
parameter_to_lambda [parameter] = lambda;
base.VisitLambda (lambda);
}
protected override void VisitParameter (ParameterExpression parameter)
{
if (lambda.Parameters.Contains (parameter))
return;
Hoist (parameter);
}
void Hoist (ParameterExpression parameter)
{
LambdaExpression lambda;
if (!parameter_to_lambda.TryGetValue (parameter, out lambda))
return;
if (hoisted_map == null)
hoisted_map = new Dictionary<LambdaExpression, List<ParameterExpression>> ();
List<ParameterExpression> hoisted;
if (!hoisted_map.TryGetValue (lambda, out hoisted)) {
hoisted = new List<ParameterExpression> ();
hoisted_map [lambda] = hoisted;
}
hoisted.Add (parameter);
}
}
List<object> globals = new List<object> ();
List<EmitContext> units = new List<EmitContext> ();
Dictionary<LambdaExpression, List<ParameterExpression>> hoisted_map;
public int AddGlobal (object global)
{
return AddItemToList (global, globals);
}
public object [] GetGlobals ()
{
return globals.ToArray ();
}
static int AddItemToList<T> (T item, IList<T> list)
{
list.Add (item);
return list.Count - 1;
}
public int AddCompilationUnit (LambdaExpression lambda)
{
DetectHoistedVariables (lambda);
return AddCompilationUnit (null, lambda);
}
public int AddCompilationUnit (EmitContext parent, LambdaExpression lambda)
{
var context = new EmitContext (this, parent, lambda);
var unit = AddItemToList (context, units);
context.Emit ();
return unit;
}
void DetectHoistedVariables (LambdaExpression lambda)
{
hoisted_map = new HoistedVariableDetector ().Process (lambda);
}
public List<ParameterExpression> GetHoistedLocals (LambdaExpression lambda)
{
if (hoisted_map == null)
return null;
List<ParameterExpression> hoisted;
hoisted_map.TryGetValue (lambda, out hoisted);
return hoisted;
}
public object [] CreateHoistedLocals (int unit)
{
var hoisted = GetHoistedLocals (units [unit].Lambda);
return new object [hoisted == null ? 0 : hoisted.Count];
}
public Expression IsolateExpression (ExecutionScope scope, object [] locals, Expression expression)
{
return new ParameterReplacer (this, scope, locals).Transform (expression);
}
public Delegate CreateDelegate ()
{
return CreateDelegate (0, new ExecutionScope (this));
}
public Delegate CreateDelegate (int unit, ExecutionScope scope)
{
return units [unit].CreateDelegate (scope);
}
}
class EmitContext {
CompilationContext context;
EmitContext parent;
LambdaExpression lambda;
DynamicMethod method;
LocalBuilder hoisted_store;
List<ParameterExpression> hoisted;
public readonly ILGenerator ig;
public bool HasHoistedLocals {
get { return hoisted != null && hoisted.Count > 0; }
}
public LambdaExpression Lambda {
get { return lambda; }
}
public EmitContext (CompilationContext context, EmitContext parent, LambdaExpression lambda)
{
this.context = context;
this.parent = parent;
this.lambda = lambda;
this.hoisted = context.GetHoistedLocals (lambda);
method = new DynamicMethod (
"lambda_method",
lambda.GetReturnType (),
CreateParameterTypes (lambda.Parameters),
typeof (ExecutionScope),
true);
ig = method.GetILGenerator ();
}
public void Emit ()
{
if (HasHoistedLocals)
EmitStoreHoistedLocals ();
lambda.EmitBody (this);
}
static Type [] CreateParameterTypes (IList<ParameterExpression> parameters)
{
var types = new Type [parameters.Count + 1];
types [0] = typeof (ExecutionScope);
for (int i = 0; i < parameters.Count; i++)
types [i + 1] = parameters [i].Type;
return types;
}
public bool IsLocalParameter (ParameterExpression parameter, ref int position)
{
position = lambda.Parameters.IndexOf (parameter);
if (position > -1) {
position++;
return true;
}
return false;
}
public Delegate CreateDelegate (ExecutionScope scope)
{
return method.CreateDelegate (lambda.Type, scope);
}
public void Emit (Expression expression)
{
expression.Emit (this);
}
public LocalBuilder EmitStored (Expression expression)
{
var local = ig.DeclareLocal (expression.Type);
expression.Emit (this);
ig.Emit (OpCodes.Stloc, local);
return local;
}
public void EmitLoadAddress (Expression expression)
{
ig.Emit (OpCodes.Ldloca, EmitStored (expression));
}
public void EmitLoadSubject (Expression expression)
{
if (expression.Type.IsValueType) {
EmitLoadAddress (expression);
return;
}
Emit (expression);
}
public void EmitLoadSubject (LocalBuilder local)
{
if (local.LocalType.IsValueType) {
EmitLoadAddress (local);
return;
}
EmitLoad (local);
}
public void EmitLoadAddress (LocalBuilder local)
{
ig.Emit (OpCodes.Ldloca, local);
}
public void EmitLoad (LocalBuilder local)
{
ig.Emit (OpCodes.Ldloc, local);
}
public void EmitCall (LocalBuilder local, IList<Expression> arguments, MethodInfo method)
{
EmitLoadSubject (local);
EmitArguments (method, arguments);
EmitCall (method);
}
public void EmitCall (LocalBuilder local, MethodInfo method)
{
EmitLoadSubject (local);
EmitCall (method);
}
public void EmitCall (Expression expression, MethodInfo method)
{
if (!method.IsStatic)
EmitLoadSubject (expression);
EmitCall (method);
}
public void EmitCall (Expression expression, IList<Expression> arguments, MethodInfo method)
{
if (!method.IsStatic)
EmitLoadSubject (expression);
EmitArguments (method, arguments);
EmitCall (method);
}
void EmitArguments (MethodInfo method, IList<Expression> arguments)
{
var parameters = method.GetParameters ();
for (int i = 0; i < parameters.Length; i++) {
var parameter = parameters [i];
var argument = arguments [i];
if (parameter.ParameterType.IsByRef) {
ig.Emit (OpCodes.Ldloca, EmitStored (argument));
continue;
}
Emit (arguments [i]);
}
}
public void EmitCall (MethodInfo method)
{
ig.Emit (
method.IsVirtual ? OpCodes.Callvirt : OpCodes.Call,
method);
}
public void EmitNullableHasValue (LocalBuilder local)
{
EmitCall (local, "get_HasValue");
}
public void EmitNullableInitialize (LocalBuilder local)
{
ig.Emit (OpCodes.Ldloca, local);
ig.Emit (OpCodes.Initobj, local.LocalType);
ig.Emit (OpCodes.Ldloc, local);
}
public void EmitNullableGetValue (LocalBuilder local)
{
EmitCall (local, "get_Value");
}
public void EmitNullableGetValueOrDefault (LocalBuilder local)
{
EmitCall (local, "GetValueOrDefault");
}
void EmitCall (LocalBuilder local, string method_name)
{
EmitCall (local, local.LocalType.GetMethod (method_name, Type.EmptyTypes));
}
public void EmitNullableNew (Type of)
{
ig.Emit (OpCodes.Newobj, of.GetConstructor (new [] { of.GetFirstGenericArgument () }));
}
public void EmitCollection<T> (IEnumerable<T> collection) where T : Expression
{
foreach (var expression in collection)
expression.Emit (this);
}
public void EmitCollection (IEnumerable<ElementInit> initializers, LocalBuilder local)
{
foreach (var initializer in initializers)
initializer.Emit (this, local);
}
public void EmitCollection (IEnumerable<MemberBinding> bindings, LocalBuilder local)
{
foreach (var binding in bindings)
binding.Emit (this, local);
}
public void EmitIsInst (Expression expression, Type candidate)
{
expression.Emit (this);
var type = expression.Type;
if (type.IsValueType)
ig.Emit (OpCodes.Box, type);
ig.Emit (OpCodes.Isinst, candidate);
}
public void EmitScope ()
{
ig.Emit (OpCodes.Ldarg_0);
}
public void EmitReadGlobal (object global)
{
EmitReadGlobal (global, global.GetType ());
}
public void EmitLoadGlobals ()
{
EmitScope ();
ig.Emit (OpCodes.Ldfld, typeof (ExecutionScope).GetField ("Globals"));
}
public void EmitReadGlobal (object global, Type type)
{
EmitLoadGlobals ();
ig.Emit (OpCodes.Ldc_I4, AddGlobal (global, type));
ig.Emit (OpCodes.Ldelem, typeof (object));
EmitLoadStrongBoxValue (type);
}
public void EmitLoadStrongBoxValue (Type type)
{
var strongbox = type.MakeStrongBoxType ();
ig.Emit (OpCodes.Isinst, strongbox);
ig.Emit (OpCodes.Ldfld, strongbox.GetField ("Value"));
}
int AddGlobal (object value, Type type)
{
return context.AddGlobal (CreateStrongBox (value, type));
}
public void EmitCreateDelegate (LambdaExpression lambda)
{
EmitScope ();
ig.Emit (OpCodes.Ldc_I4, AddChildContext (lambda));
if (hoisted_store != null)
ig.Emit (OpCodes.Ldloc, hoisted_store);
else
ig.Emit (OpCodes.Ldnull);
ig.Emit (OpCodes.Callvirt, typeof (ExecutionScope).GetMethod ("CreateDelegate"));
ig.Emit (OpCodes.Castclass, lambda.Type);
}
void EmitStoreHoistedLocals ()
{
EmitHoistedLocalsStore ();
for (int i = 0; i < hoisted.Count; i++)
EmitStoreHoistedLocal (i, hoisted [i]);
}
void EmitStoreHoistedLocal (int position, ParameterExpression parameter)
{
ig.Emit (OpCodes.Ldloc, hoisted_store);
ig.Emit (OpCodes.Ldc_I4, position);
parameter.Emit (this);
EmitCreateStrongBox (parameter.Type);
ig.Emit (OpCodes.Stelem, typeof (object));
}
public void EmitLoadHoistedLocalsStore ()
{
ig.Emit (OpCodes.Ldloc, hoisted_store);
}
void EmitCreateStrongBox (Type type)
{
ig.Emit (OpCodes.Newobj, type.MakeStrongBoxType ().GetConstructor (new [] { type }));
}
void EmitHoistedLocalsStore ()
{
EmitScope ();
hoisted_store = ig.DeclareLocal (typeof (object []));
ig.Emit (OpCodes.Callvirt, typeof (ExecutionScope).GetMethod ("CreateHoistedLocals"));
ig.Emit (OpCodes.Stloc, hoisted_store);
}
public void EmitLoadLocals ()
{
ig.Emit (OpCodes.Ldfld, typeof (ExecutionScope).GetField ("Locals"));
}
public void EmitParentScope ()
{
ig.Emit (OpCodes.Ldfld, typeof (ExecutionScope).GetField ("Parent"));
}
public void EmitIsolateExpression ()
{
ig.Emit (OpCodes.Callvirt, typeof (ExecutionScope).GetMethod ("IsolateExpression"));
}
public int IndexOfHoistedLocal (ParameterExpression parameter)
{
if (!HasHoistedLocals)
return -1;
return hoisted.IndexOf (parameter);
}
public bool IsHoistedLocal (ParameterExpression parameter, ref int level, ref int position)
{
if (parent == null)
return false;
if (parent.hoisted != null) {
position = parent.hoisted.IndexOf (parameter);
if (position > -1)
return true;
}
level++;
return parent.IsHoistedLocal (parameter, ref level, ref position);
}
int AddChildContext (LambdaExpression lambda)
{
return context.AddCompilationUnit (this, lambda);
}
static object CreateStrongBox (object value, Type type)
{
return Activator.CreateInstance (
type.MakeStrongBoxType (), value);
}
}
}
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