[Mono] Actually AOT things in AOT mode; prevent JIT fall back (#1966)

Author: Nathan Ricci

src/BenchmarkDotNet/ConsoleArguments/ConfigParser.cs

@@ -410,7 +410,7 @@ private static Job CreateAotJob(Job baseJob, CommandLineOptions options, Runtime
 
         private static Job MakeMonoAOTLLVMJob(Job baseJob, CommandLineOptions options, string msBuildMoniker)
         {
-            var monoAotLLVMRuntime = new MonoAotLLVMRuntime(aotCompilerPath: options.AOTCompilerPath, msBuildMoniker: msBuildMoniker);
+            var monoAotLLVMRuntime = new MonoAotLLVMRuntime(aotCompilerPath: options.AOTCompilerPath, aotCompilerMode: options.AOTCompilerMode, msBuildMoniker: msBuildMoniker);
 
             var toolChain = MonoAotLLVMToolChain.From(
             new NetCoreAppSettings(

src/BenchmarkDotNet/Environments/Runtimes/MonoAotLLVMRuntime.cs

@@ -3,6 +3,7 @@
 using System.IO;
 using BenchmarkDotNet.Extensions;
 using BenchmarkDotNet.Jobs;
+using BenchmarkDotNet.Toolchains.MonoAotLLVM;
 
 namespace BenchmarkDotNet.Environments
 {
@@ -12,20 +13,22 @@ public class MonoAotLLVMRuntime : Runtime, IEquatable<MonoAotLLVMRuntime>
         internal static readonly MonoAotLLVMRuntime Default = new MonoAotLLVMRuntime();
 
         public FileInfo AOTCompilerPath { get; }
+        public MonoAotCompilerMode AOTCompilerMode { get;  }
 
         public override bool IsAOT => true;
 
         /// <summary>
         /// creates new instance of MonoAotLLVMRuntime
         /// </summary>
-        public MonoAotLLVMRuntime(FileInfo aotCompilerPath, string msBuildMoniker = "net6.0", string displayName = "MonoAOTLLVM") : base(RuntimeMoniker.MonoAOTLLVM, msBuildMoniker, displayName)
+        public MonoAotLLVMRuntime(FileInfo aotCompilerPath, MonoAotCompilerMode aotCompilerMode, string msBuildMoniker = "net6.0", string displayName = "MonoAOTLLVM") : base(RuntimeMoniker.MonoAOTLLVM, msBuildMoniker, displayName)
         {
             if (aotCompilerPath == null)
                 throw new ArgumentNullException(paramName: nameof(aotCompilerPath));
             if (aotCompilerPath.IsNotNullButDoesNotExist())
                 throw new FileNotFoundException($"Provided {nameof(aotCompilerPath)} file: \"{aotCompilerPath.FullName}\" doest NOT exist");
 
             AOTCompilerPath = aotCompilerPath;
+            AOTCompilerMode = aotCompilerMode;
         }
 
         // this ctor exists only for the purpose of having .Default property that returns something consumable by RuntimeInformation.GetCurrentRuntime()

src/BenchmarkDotNet/Extensions/ProcessExtensions.cs

@@ -10,8 +10,10 @@
 using BenchmarkDotNet.Portability;
 using BenchmarkDotNet.Running;
 using BenchmarkDotNet.Toolchains.CoreRun;
+using BenchmarkDotNet.Toolchains.MonoAotLLVM;
 using JetBrains.Annotations;
 
+
 namespace BenchmarkDotNet.Extensions
 {
     // we need it public to reuse it in the auto-generated dll
@@ -129,6 +131,16 @@ internal static void SetEnvironmentVariables(this ProcessStartInfo start, Benchm
             // disable ReSharper's Dynamic Program Analysis (see https://github.com/dotnet/BenchmarkDotNet/issues/1871 for details)
             start.EnvironmentVariables["JETBRAINS_DPA_AGENT_ENABLE"] = "0";
 
+            if (benchmarkCase.Job.Infrastructure.Toolchain is MonoAotLLVMToolChain)
+            {
+                MonoAotLLVMRuntime aotruntime = (MonoAotLLVMRuntime)benchmarkCase.GetRuntime();
+
+                if (aotruntime.AOTCompilerMode == MonoAotCompilerMode.llvm)
+                {
+                    start.EnvironmentVariables["MONO_ENV_OPTIONS"] = "--full-aot";
+                }
+            }
+
             if (!benchmarkCase.Job.HasValue(EnvironmentMode.EnvironmentVariablesCharacteristic))
                 return;
 

src/BenchmarkDotNet/Templates/MonoAOTLLVMCsProj.txt

@@ -40,23 +40,29 @@
 
    <PropertyGroup>
       <PublishDirFullPath>$([System.IO.Path]::GetFullPath($(PublishDir)))</PublishDirFullPath>
+      <SharedLibraryType Condition="$([MSBuild]::IsOSPlatform('OSX'))">Dylib</SharedLibraryType>
+      <SharedLibraryType Condition="$([MSBuild]::IsOSPlatform('Windows'))">Dll</SharedLibraryType>
+      <SharedLibraryType Condition="$([MSBuild]::IsOSPlatform('Linux'))">So</SharedLibraryType>
+      <SharedLibraryType Condition="$([MSBuild]::IsOSPlatform('FreeBSD'))">Dll</SharedLibraryType>
    </PropertyGroup>
 
    <ItemGroup>
      <AotInputAssemblies Include="$(PublishDirFullPath)\*.dll">
-        <AotArguments>@(MonoAOTCompilerDefaultAotArguments, ';')</AotArguments>
+        <AotArguments>@(MonoAOTCompilerDefaultAotArguments, ';');mcpu=native</AotArguments>
         <ProcessArguments>@(MonoAOTCompilerDefaultProcessArguments, ';')</ProcessArguments>
      </AotInputAssemblies>
    </ItemGroup>
 
+
    <MonoAOTCompiler
         CompilerBinaryPath="$COMPILERBINARYPATH$"
-        Mode="Normal"
-        OutputType="Normal"
+        Mode="Full"
+        OutputType="Library"
+        LibraryFormat="$(SharedLibraryType)"
         Assemblies="@(AotInputAssemblies)"
         UseLLVM="$USELLVM$"
         LLVMPath="$(MicrosoftNetCoreAppRuntimePackDir)\runtimes\$(RuntimeIdentifier)\native"
-	    OutputDir="$(PublishDir)"
+        OutputDir="$(PublishDir)"
         UseAotDataFile="false"
         IntermediateOutputPath="$(IntermediateOutputPath)">
         <Output TaskParameter="CompiledAssemblies" ItemName="BundleAssemblies" />