FastExpressionCompiler 4.0.1Prefix Reserved
dotnet add package FastExpressionCompiler --version 4.0.1
NuGet\Install-Package FastExpressionCompiler -Version 4.0.1
<PackageReference Include="FastExpressionCompiler" Version="4.0.1" />
paket add FastExpressionCompiler --version 4.0.1
#r "nuget: FastExpressionCompiler, 4.0.1"
// Install FastExpressionCompiler as a Cake Addin #addin nuget:?package=FastExpressionCompiler&version=4.0.1 // Install FastExpressionCompiler as a Cake Tool #tool nuget:?package=FastExpressionCompiler&version=4.0.1
<img src="./logo.png" alt="logo"/>
Targets .NET 6, 7, .NET Standard 2.0, 2.1 and .NET 4.5
The project was originally a part of the DryIoc, so check it out 😉
ExpressionTree compilation is used by the wide variety of tools, e.g. IoC/DI containers, Serializers, ORMs and OOMs.
Expression.Compile() is just slow.
Moreover the compiled delegate may be slower than the manually created delegate because of the reasons:
Expression.Compile creates a DynamicMethod and associates it with an anonymous assembly to run it in a sand-boxed environment. This makes it safe for a dynamic method to be emitted and executed by partially trusted code but adds some run-time overhead.
See also a deep dive to Delegate internals.
.CompileFast() extension method is 10-40x times faster than
The compiled delegate may be in some cases a lot faster than the one produced by
Note: The actual performance may vary depending on the multiple factors: platform, how complex is expression, does it have a closure, does it contain nested lambdas, etc.
In addition, the memory consumption taken by the compilation will be much smaller (check the
Allocated column in the benchmarks below).
Updated to .NET 8.0
BenchmarkDotNet v0.13.10, Windows 11 (10.0.22621.2428/22H2/2022Update/SunValley2) 11th Gen Intel Core i7-1185G7 3.00GHz, 1 CPU, 8 logical and 4 physical cores .NET SDK 8.0.100-rc.2.23502.2 [Host] : .NET 8.0.0 (18.104.22.168906), X64 RyuJIT AVX2 DefaultJob : .NET 8.0.0 (22.214.171.124906), X64 RyuJIT AVX2
Hoisted expression with the constructor and two arguments in closure
var a = new A(); var b = new B(); Expression<Func<X>> e = () => new X(a, b);
|Compile||121.969 us||2.4180 us||5.6040 us||120.830 us||35.77||2.46||0.7324||-||4.49 KB||2.92|
|CompileFast||3.406 us||0.0677 us||0.1820 us||3.349 us||1.00||0.00||0.2441||0.2365||1.54 KB||1.00|
Invoking the compiled delegate (comparing to the direct constructor call):
|DirectConstructorCall||5.734 ns||0.1501 ns||0.2745 ns||5.679 ns||0.86||0.05||0.0051||32 B||1.00|
|CompiledLambda||6.857 ns||0.1915 ns||0.5434 ns||6.704 ns||1.01||0.09||0.0051||32 B||1.00|
|FastCompiledLambda||6.746 ns||0.1627 ns||0.1442 ns||6.751 ns||1.00||0.00||0.0051||32 B||1.00|
Hoisted expression with the static method and two nested lambdas and two arguments in closure
var a = new A(); var b = new B(); Expression<Func<X>> getXExpr = () => CreateX((aa, bb) => new X(aa, bb), new Lazy<A>(() => a), b);
|Compile||442.02 us||8.768 us||21.998 us||40.00||2.34||1.9531||0.9766||12.04 KB||2.61|
|CompileFast||11.06 us||0.221 us||0.441 us||1.00||0.00||0.7324||0.7019||4.62 KB||1.00|
Invoking compiled delegate comparing to direct method call:
|DirectMethodCall||35.51 ns||0.783 ns||1.308 ns||0.86||0.08||0.0267||168 B||1.62|
|Invoke_Compiled||1,096.15 ns||21.507 ns||41.437 ns||27.15||2.75||0.0420||264 B||2.54|
|Invoke_CompiledFast||37.65 ns||1.466 ns||4.299 ns||1.00||0.00||0.0166||104 B||1.00|
Manually composed expression with parameters and closure
var a = new A(); var bParamExpr = Expression.Parameter(typeof(B), "b"); var expr = Expression.Lambda( Expression.New(_ctorX, Expression.Constant(a, typeof(A)), bParamExpr), bParamExpr);
|Compile_SystemExpression||89.076 us||2.6699 us||7.6605 us||85.180 us||28.12||3.05||0.7324||0.4883||4.74 KB||3.41|
|CompileFast_SystemExpression||3.138 us||0.0550 us||0.0565 us||3.118 us||0.99||0.03||0.2213||0.2136||1.39 KB||1.00|
|CompileFast_LightExpression||3.180 us||0.0602 us||0.0591 us||3.163 us||1.00||0.00||0.2213||0.2136||1.39 KB||1.00|
Invoking the compiled delegate compared to the normal delegate and the direct call:
|DirectCall||8.388 ns||0.2655 ns||0.7575 ns||8.092 ns||1.00||0.07||0.0051||32 B||1.00|
|Compiled_SystemExpression||9.474 ns||0.1870 ns||0.4105 ns||9.381 ns||1.10||0.05||0.0051||32 B||1.00|
|CompiledFast_SystemExpression||8.575 ns||0.1624 ns||0.1440 ns||8.517 ns||1.00||0.02||0.0051||32 B||1.00|
|CompiledFast_LightExpression||8.584 ns||0.0776 ns||0.0862 ns||8.594 ns||1.00||0.00||0.0051||32 B||1.00|
FastExpressionCompiler.LightExpression.Expression vs System.Linq.Expressions.Expression
FastExpressionCompiler.LightExpression.Expression is the lightweight version of
It is designed to be a drop-in replacement for the System Expression - just install the FastExpressionCompiler.LightExpression package instead of FastExpressionCompiler and replace the usings
using System.Linq.Expressions; using static System.Linq.Expressions.Expression;
using static FastExpressionCompiler.LightExpression.Expression; namespace FastExpressionCompiler.LightExpression.UnitTests
You may look at it as a bare-bone wrapper for the computation operation node which helps you to compose the computation tree (without messing with the IL emit directly).
It won't validate operations compatibility for the tree the way
System.Linq.Expression does it, and partially why it is so slow.
Hopefully you are checking the expression arguments yourself and not waiting for the
Expression exceptions to blow-up.
Creating the expression:
|Create_SystemExpression||1,039.5 ns||20.75 ns||45.98 ns||8.29||0.50||0.2060||1304 B||2.63|
|Create_LightExpression||125.7 ns||2.46 ns||5.99 ns||1.00||0.00||0.0789||496 B||1.00|
|Create_LightExpression_with_intrinsics||130.0 ns||2.47 ns||6.25 ns||1.04||0.07||0.0777||488 B||0.98|
Creating and compiling:
|Create_SystemExpression_and_Compile||159.184 us||2.9731 us||7.1235 us||37.34||1.65||0.9766||0.4883||7.4 KB||3.06|
|Create_SystemExpression_and_CompileFast||5.923 us||0.0996 us||0.1771 us||1.34||0.05||0.5188||0.5035||3.27 KB||1.35|
|Create_LightExpression_and_CompileFast||4.399 us||0.0484 us||0.0453 us||1.00||0.00||0.3815||0.3662||2.42 KB||1.00|
|CreateLightExpression_and_CompileFast_with_intrinsic||4.384 us||0.0835 us||0.0697 us||1.00||0.02||0.3815||0.3662||2.35 KB||0.97|
Difference between FastExpressionCompiler and FastExpressionCompiler.LightExpression
- Provides the
CompileFastextension methods for the
- Provides the
CompileFastextension methods for
- Provides the drop-in expression replacement with the less consumed memory and the faster construction at the cost of the less validation.
- Includes its own
ToExpressionmethod to convert back to the
Both FastExpressionCompiler and FastExpressionCompiler.LightExpression
ToCSharpString()method to output the compile-able C# code represented by expression.
ToExpressionString()method to output the expression construction C# code, so given the expression object you'll get e.g.
Who's using it
How to use
Install from the NuGet and add the
using FastExpressionCompiler; and replace the call to the
.Compile() with the
.CompileFast() extension method.
CompileFast has an optional parameter
bool ifFastFailedReturnNull = false to disable fallback to
Hoisted lambda expression (created by the C# Compiler):
var a = new A(); var b = new B(); Expression<Func<X>> expr = () => new X(a, b); var getX = expr.CompileFast(); var x = getX();
Manually composed lambda expression:
var a = new A(); var bParamExpr = Expression.Parameter(typeof(B), "b"); var expr = Expression.Lambda( Expression.New(_ctorX, Expression.Constant(a, typeof(A)), bParamExpr), bParamExpr); var f = expr.CompileFast(); var x = f(new B());
Note: You may simplify Expression usage and enable faster refactoring with the C#
using static statement:
using static System.Linq.Expressions.Expression; // or // using static FastExpressionCompiler.LightExpression.Expression; var a = new A(); var bParamExpr = Parameter(typeof(B), "b"); var expr = Lambda( New(_ctorX, Constant(a, typeof(A)), bParamExpr), bParamExpr); var f = expr.CompileFast(); var x = f(new B());
How it works
The idea is to provide the fast compilation for the supported expression types
and fallback to the system
Expression.Compile() for the not supported types:
What's not supported yet
FEC V3 does not support yet:
NewArrayInitmulti-dimensional array initializer is not supported yet
To find what nodes are not supported in your expression you may use the technic described below in the Diagnostics section.
The compilation is done by traversing the expression nodes and emitting the IL. The code is tuned for the performance and the minimal memory consumption.
The expression is traversed twice:
- 1st round is to collect the constants and nested lambdas into the closure objects.
- 2nd round is to emit the IL code and create the delegate using the
If visitor finds the not supported expression node or the error condition,
the compilation is aborted, and
null is returned enabling the fallback to System
FEC V3 adds powerful diagnostics tools.
You may pass the optional
CompilerFlags.EnableDelegateDebugInfo into the
EnableDelegateDebugInfo adds the diagnostic info into the compiled delegate including its source Expression and C# code.
Can be used as following:
var f = e.CompileFast(true, CompilerFlags.EnableDelegateDebugInfo); var di = f.Target as IDelegateDebugInfo; Assert.IsNotNull(di.Expression); Assert.IsNotNull(di.ExpressionString); Assert.IsNotNull(di.CSharpString);
Those conversion capabilities are also available as the
ToExpressionString extension methods.
Besides that, when converting the source expression to either C# code or to the Expression construction code you may find
// NOT_SUPPORTED_EXPRESSION comments marking the not supported yet expressions by FEC. So you may verify the presence or absence of this comment in a test.
ThrowOnNotSupportedExpression and NotSupported cases enum
FEC V3.1 adds to the compiler flags the
so that compiling the expression with not supported node will throw the respective exception instead of returning
To get the actual list of the not supported cases you may check
System.Linq.Expressions.Expressionfor the faster expression creation.
.TryCompileWithoutClosuremethods when you know the expression at hand and may skip the first traversing round, e.g. for the "static" expression which does not contain the bound constants. Note: You cannot skip the 1st round if the expression contains the
<a target="_blank" href="https://icons8.com/icons/set/bitten-ice-pop">Bitten Ice Pop icon</a> icon by <a target="_blank" href="https://icons8.com">Icons8</a>
|Product||Versions Compatible and additional computed target framework versions.|
|.NET||net5.0 was computed. net5.0-windows was computed. net6.0 is compatible. net6.0-android was computed. net6.0-ios was computed. net6.0-maccatalyst was computed. net6.0-macos was computed. net6.0-tvos was computed. net6.0-windows was computed. net7.0 is compatible. net7.0-android was computed. net7.0-ios was computed. net7.0-maccatalyst was computed. net7.0-macos was computed. net7.0-tvos was computed. net7.0-windows was computed. net8.0 was computed. net8.0-android was computed. net8.0-ios was computed. net8.0-maccatalyst was computed. net8.0-macos was computed. net8.0-tvos was computed. net8.0-windows was computed.|
|.NET Core||netcoreapp2.0 was computed. netcoreapp2.1 was computed. netcoreapp2.2 was computed. netcoreapp3.0 was computed. netcoreapp3.1 was computed.|
|.NET Standard||netstandard2.0 is compatible. netstandard2.1 is compatible.|
|.NET Framework||net45 is compatible. net451 was computed. net452 was computed. net46 was computed. net461 was computed. net462 was computed. net463 was computed. net47 was computed. net471 was computed. net472 was computed. net48 was computed. net481 was computed.|
|MonoAndroid||monoandroid was computed.|
|MonoMac||monomac was computed.|
|MonoTouch||monotouch was computed.|
|Tizen||tizen40 was computed. tizen60 was computed.|
|Xamarin.iOS||xamarinios was computed.|
|Xamarin.Mac||xamarinmac was computed.|
|Xamarin.TVOS||xamarintvos was computed.|
|Xamarin.WatchOS||xamarinwatchos was computed.|
NuGet packages (52)
Showing the top 5 NuGet packages that depend on FastExpressionCompiler:
Rules Engine is a package for abstracting business logic/rules/policies out of the system. This works in a very simple way by giving you an ability to put your rules in a store outside the core logic of the system thus ensuring that any change in rules doesn't affect the core system.
Code Generation Chicanery for .Net
DotVVM is an open source ASP.NET-based framework which allows to build interactive web apps easily by using mostly C# and HTML.
Miruken handles your application
Generates valid, readable C# from an expression tree, and can annotate that code with runtime values. Useful for e.g. code generation and unit testing assertions.
GitHub repositories (12)
Showing the top 5 popular GitHub repositories that depend on FastExpressionCompiler:
A fast, fun and stimulating object to object Mapper
A Json based Rules Engine with extensive Dynamic expression support
Next Generation .NET Command and Message Bus
该仓库为 https://github.com/ldqk/Masuit.Tools 的镜像仓库，代码更新存在较大的延迟。建议前往源仓库：https://github.com/ldqk/Masuit.Tools
## v4.0.1 Bug-fix release
- fixed: #374 CompileFast doesn't work with HasFlag
## v4.0.0 Major release
- fixed: #352 xxxAssign doesn't work with MemberAccess
- fixed: #353 NullReferenceException when calling CompileFast() results
- fixed: #357 Invalid program exception
- fixed: #366 FastExpressionCompiler[v3.3.4] gives incorrect results in some linq operations
- fixed: #368 Fix duplicate nested lambda compilation
- fixed: #374 CompileFast doesn't work with HasFlag
- added: #264 Optimize the array index emit to emit specific Ldelem_ code instead of generic Ldelem
- added: #273 Implement IArgumentProvider for the BlockExpression to minimize the consumed memory
- added: #346 Is it possible to implement ref local variables?
- added: #359 Improve the performance of variable lookup
- added: #367 Better diagnostics and debugging with error codes from Collect and Compile rounds
- added: #369 Decrease memory occupied by the LightExpression Block by storing Expression in SmallList (partly on stack)
- added: #370 Optimize any nested lambda compilation (LINQ) by compiling right after collect one-by-one
- added: #372 Support LightExpression.Expression.TryConvertDelegateIntrinsic for converting one type of delegate to another
- added: #373 Support custom C# printing for the LightExpression.Expression