[Mono] Add the capability of trimming IL code of individual methods

src/mono/mono/mini/aot-compiler.c

@@ -9828,8 +9828,9 @@ compile_method (MonoAotCompile *acfg, MonoMethod *method)
 	mono_atomic_inc_i32 (&acfg->stats.ccount);
 
 	if (acfg->aot_opts.compiled_methods_outfile && acfg->compiled_methods_outfile != NULL) {
-		if (!mono_method_is_generic_impl (method) && method->token != 0)
+		if (!mono_method_is_generic_impl (method) && method->token != 0) {
 			fprintf (acfg->compiled_methods_outfile, "%x\n", method->token);
+		}
 	}
 }
 
@@ -14832,6 +14833,10 @@ aot_assembly (MonoAssembly *ass, guint32 jit_opts, MonoAotOptions *aot_options)
 		acfg->compiled_methods_outfile = fopen (acfg->aot_opts.compiled_methods_outfile, "w+");
 		if (!acfg->compiled_methods_outfile)
 			aot_printerrf (acfg, "Unable to open compiled-methods-outfile specified file %s\n", acfg->aot_opts.compiled_methods_outfile);
+		else {
+			fprintf(acfg->compiled_methods_outfile, "%s\n", ass->image->filename);
+			fprintf(acfg->compiled_methods_outfile, "%s\n", ass->image->guid);
+		}
 	}
 
 	if (acfg->aot_opts.data_outfile) {

src/mono/sample/HelloWorld/HelloWorld.csproj

@@ -25,6 +25,8 @@
       LibraryFormat="$(_AotLibraryFormat)"
       Assemblies="@(AotInputAssemblies)"
       OutputDir="$(PublishDir)"
+      CollectCompiledMethods="$(StripILCode)"
+      CompiledMethodsOutputDirectory="$(CompiledMethodsOutputDirectory)"
       IntermediateOutputPath="$(IntermediateOutputPath)"
       UseAotDataFile="$(UseAotDataFile)"
       CacheFilePath="$(IntermediateOutputPath)aot_compiler_cache.json"
@@ -35,4 +37,26 @@
       <Output TaskParameter="CompiledAssemblies" ItemName="BundleAssemblies" />
     </MonoAOTCompiler>
   </Target>
+
+  <UsingTask TaskName="ILStrip"
+             AssemblyFile="$(MonoTargetsTasksAssemblyPath)" />
+
+  <Target Name="StripILCode" Condition="'$(StripILCode)' == 'true'" AfterTargets="AOTCompileApp">
+    <PropertyGroup>
+      <TrimIndividualMethods>true</TrimIndividualMethods>
+    </PropertyGroup>
+
+    <ILStrip
+      TrimIndividualMethods="$(TrimIndividualMethods)"
+      Assemblies="@(BundleAssemblies)">
+      <Output TaskParameter="TrimmedAssemblies" ItemName="TrimmedAssemblies" />
+    </ILStrip>
+
+    <Copy
+        SourceFiles="@(TrimmedAssemblies->Metadata('TrimmedAssemblyFileName'))"
+        DestinationFiles="@(TrimmedAssemblies)"
+        OverwriteReadOnlyFiles="true"
+    />
+    <Delete Files="@(TrimmedAssemblies->Metadata('TrimmedAssemblyFileName'))" />
+  </Target>
 </Project>

src/mono/sample/HelloWorld/Makefile

@@ -6,6 +6,8 @@ MONO_CONFIG?=Debug
 MONO_ARCH?=$(shell . $(TOP)eng/native/init-os-and-arch.sh && echo $${arch})
 TARGET_OS?=$(shell . $(TOP)eng/native/init-os-and-arch.sh && echo $${os})
 AOT?=false
+StripILCode?=false
+CompiledMethodsOutputDirectory?= #<path-to-a-writable-directory>
 
 #NET_TRACE_PATH=<path-to-trace-of-sample>
 #PGO_BINARY_PATH=<path-to-dotnet-pgo-executable>
@@ -18,6 +20,8 @@ publish:
 	-c $(MONO_CONFIG) \
 	-r $(TARGET_OS)-$(MONO_ARCH) \
 	/p:RunAOTCompilation=$(AOT) \
+	/p:StripILCode=$(StripILCode) \
+	/p:CompiledMethodsOutputDirectory=$(CompiledMethodsOutputDirectory) \
 	'/p:NetTracePath="$(NET_TRACE_PATH)"' \
 	'/p:PgoBinaryPath="$(PGO_BINARY_PATH)"' \
 	'/p:MibcProfilePath="$(MIBC_PROFILE_PATH)"'

src/tasks/AotCompilerTask/MonoAOTCompiler.cs

@@ -67,6 +67,7 @@ public class MonoAOTCompiler : Microsoft.Build.Utilities.Task
     ///   - LlvmObjectFile (if using LLVM)
     ///   - LlvmBitcodeFile (if using LLVM-only)
     ///   - ExportsFile (used in LibraryMode only)
+    ///   - MethodTokenFile (when using CollectCompiledMethods=true)
     /// </summary>
     [Output]
     public ITaskItem[]? CompiledAssemblies { get; set; }
@@ -152,6 +153,16 @@ public class MonoAOTCompiler : Microsoft.Build.Utilities.Task
     /// </summary>
     public bool UseDwarfDebug { get; set; }
 
+    /// <summary>
+    /// Instructs the AOT compiler to print the list of aot compiled methods
+    /// </summary>
+    public bool CollectCompiledMethods { get; set; }
+
+    /// <summary>
+    /// Directory to store the aot output when using switch compiled-methods-outfile
+    /// </summary>
+    public string? CompiledMethodsOutputDirectory { get; set; }
+
     /// <summary>
     /// File to use for profile-guided optimization, *only* the methods described in the file will be AOT compiled.
     /// </summary>
@@ -436,6 +447,17 @@ private bool ProcessAndValidateArguments()
                 throw new LogAsErrorException($"Could not find {fullPath} to AOT");
         }
 
+        if (CollectCompiledMethods)
+        {
+            if (string.IsNullOrEmpty(CompiledMethodsOutputDirectory))
+                throw new LogAsErrorException($"{nameof(CompiledMethodsOutputDirectory)} is empty. When {nameof(CollectCompiledMethods)} is set to true, the user needs to provide a directory for {nameof(CompiledMethodsOutputDirectory)}.");
+
+            if (!Directory.Exists(CompiledMethodsOutputDirectory))
+            {
+                Directory.CreateDirectory(CompiledMethodsOutputDirectory);
+            }
+        }
+
         return !Log.HasLoggedErrors;
     }
 
@@ -711,6 +733,23 @@ private PrecompileArguments GetPrecompileArgumentsFor(ITaskItem assemblyItem, st
             aotArgs.Add("dedup-skip");
         }
 
+        if (CollectCompiledMethods)
+        {
+            string assemblyName = assemblyFilename.Replace(".", "_");
+            string outputFileName = assemblyName + "_compiled_methods.txt";
+            string outputFilePath;
+            if (string.IsNullOrEmpty(CompiledMethodsOutputDirectory))
+            {
+                outputFilePath = outputFileName;
+            }
+            else
+            {
+                outputFilePath = Path.Combine(CompiledMethodsOutputDirectory, outputFileName);
+            }
+            aotArgs.Add($"compiled-methods-outfile={outputFilePath}");
+            aotAssembly.SetMetadata("MethodTokenFile", outputFilePath);
+        }
+
         // compute output mode and file names
         if (parsedAotMode == MonoAotMode.LLVMOnly || parsedAotMode == MonoAotMode.LLVMOnlyInterp)
         {