[mono][aot] Enable dedup by default for iOS (#81319)

* Enable dedup in HelloiOS app

* Disable call transformation for MONO_PATCH_INFO_METHOD as some callees require initialization

* Fix build warnings

* Enable dedup by default for ios

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

@@ -6589,6 +6589,8 @@ emit_and_reloc_code (MonoAotCompile *acfg, MonoMethod *method, guint8 *code, gui
 						direct_call_target = symbol;
 						patch_info->type = MONO_PATCH_INFO_NONE;
 					} else if ((m_class_get_image (patch_info->data.method->klass) == acfg->image) && !got_only && is_direct_callable (acfg, method, patch_info)) {
+#if 0
+						// FIXME: Currently not used. It fails as some callees require initialization.
 						MonoCompile *callee_cfg = (MonoCompile *)g_hash_table_lookup (acfg->method_to_cfg, cmethod);
 
 						// Don't compile inflated methods if we're doing dedup
@@ -6602,6 +6604,7 @@ emit_and_reloc_code (MonoAotCompile *acfg, MonoMethod *method, guint8 *code, gui
 							patch_info->type = MONO_PATCH_INFO_NONE;
 							acfg->stats.direct_calls ++;
 						}
+#endif
 					}
 
 					acfg->stats.all_calls ++;
@@ -14891,9 +14894,12 @@ aot_assembly (MonoAssembly *ass, guint32 jit_opts, MonoAotOptions *aot_options)
 	TV_GETTIME (btv);
 
 	acfg->stats.jit_time = GINT64_TO_INT (TV_ELAPSED (atv, btv));
-
+	// Current implementation uses dedup_methods hash table for storing extra methods which are emitted in a dedup AOT image.
+	// Previously, cfg->skip flag in dedup_skip_methods is used for indicating if a method should be emitted in an AOT image.
+	// Method dedup_skip_methods is used only for wasm.
+#ifdef TARGET_WASM
 	dedup_skip_methods (acfg);
-
+#endif
 	if (acfg->dedup_collect_only) {
 		/* We only collected methods from this assembly */
 		acfg_free (acfg);

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

@@ -4492,11 +4492,16 @@ inst_is_private (MonoGenericInst *inst)
 gboolean
 mono_aot_can_dedup (MonoMethod *method)
 {
-#ifdef TARGET_WASM
+	// Dedup enabled for wasm and iOS
+#if defined(TARGET_WASM) || defined(TARGET_IOS)
 	/* Use a set of wrappers/instances which work and useful */
 	switch (method->wrapper_type) {
 	case MONO_WRAPPER_RUNTIME_INVOKE:
+#ifdef TARGET_WASM
 		return TRUE;
+#else
+		return FALSE;
+#endif
 		break;
 	case MONO_WRAPPER_OTHER: {
 		WrapperInfo *info = mono_marshal_get_wrapper_info (method);

src/mono/msbuild/apple/build/AppleApp.props

@@ -2,6 +2,7 @@
   <!-- iOS/tvOS device + arm64 simulators need to AOT -->
   <PropertyGroup Condition="'$(TargetOS)' == 'ios' or '$(TargetOS)' == 'tvos' or (('$(TargetOS)' == 'iossimulator' or '$(TargetOS)' == 'tvossimulator') And '$(TargetArchitecture)' == 'arm64')">
     <RunAOTCompilation Condition="'$(RunAOTCompilation)' == ''">true</RunAOTCompilation>
+    <iOSLikeDedup Condition="'$(RunAOTCompilation)' == 'true' and '$(TargetOS)' == 'ios'">true</iOSLikeDedup>
   </PropertyGroup>
 
   <!-- iOS/tvOS arm64 simulators do not support JIT, so force interpreter fallback, devices should FullAOT -->

src/mono/msbuild/apple/build/AppleApp.targets

@@ -88,6 +88,25 @@
 
     <MakeDir Directories="$(_MobileIntermediateOutputPath)" />
 
+    <PropertyGroup Condition="'$(iOSLikeDedup)' == 'true'">
+      <_iOSLikeDedupAssembly>$(AppleAppDir)\aot-instances.dll</_iOSLikeDedupAssembly>
+    </PropertyGroup>
+    <WriteLinesToFile Condition="'$(iOSLikeDedup)' == 'true'" File="$(_MobileIntermediateOutputPath)/aot-instances.cs" Overwrite="true" Lines="" WriteOnlyWhenDifferent="true" />
+    <Csc Condition="'$(iOSLikeDedup)' == 'true'"
+      Sources="$(_MobileIntermediateOutputPath)\aot-instances.cs"
+      OutputAssembly="$(_iOSLikeDedupAssembly)"
+      TargetType="library"
+      Deterministic="true"
+      References="@(ReferencePath)"
+      ToolExe="$(CscToolExe)"
+      ToolPath="$(CscToolPath)" />
+    <ItemGroup Condition="'$(iOSLikeDedup)' == 'true'">
+      <_AotInputAssemblies Include="$(_iOSLikeDedupAssembly)">
+        <AotArguments>@(MonoAOTCompilerDefaultAotArguments, ';')</AotArguments>
+        <ProcessArguments>@(MonoAOTCompilerDefaultProcessArguments, ';')</ProcessArguments>
+      </_AotInputAssemblies>
+    </ItemGroup>
+
     <MonoAOTCompiler Condition="'$(RunAOTCompilation)' == 'true'"
         CompilerBinaryPath="@(MonoAotCrossCompiler->WithMetadataValue('RuntimeIdentifier','$(TargetOS)-$(TargetArchitecture.ToLowerInvariant())'))"
         OutputDir="$(_MobileIntermediateOutputPath)"
@@ -98,6 +117,7 @@
         AotModulesTableLanguage="ObjC"
         UseLLVM="$(MonoEnableLLVM)"
         LLVMPath="$(MonoAotCrossDir)"
+        DedupAssembly="$(_iOSLikeDedupAssembly)"
         IntermediateOutputPath="$(_MobileIntermediateOutputPath)">
         <Output TaskParameter="CompiledAssemblies" ItemName="_AppleAssembliesInternal" />
     </MonoAOTCompiler>

src/mono/sample/iOS/Program.csproj

@@ -6,6 +6,7 @@
     <TargetOS Condition="'$(TargetOS)' == ''">ios</TargetOS>
     <TargetOS Condition="'$(TargetsiOSSimulator)' == 'true'">iossimulator</TargetOS>
     <DeployAndRun Condition="'$(DeployAndRun)' == ''">true</DeployAndRun>
+    <iOSLikeDedup Condition="'$(TargetOS)' == 'ios'">true</iOSLikeDedup>
     <RuntimeIdentifier>$(TargetOS)-$(TargetArchitecture)</RuntimeIdentifier>
     <DefineConstants Condition="'$(ArchiveTests)' == 'true'">$(DefineConstants);CI_TEST</DefineConstants>
     <AppName>HelloiOS</AppName>
@@ -42,6 +43,19 @@
 
     <RemoveDir Directories="$(AppDir)" />
 
+    <PropertyGroup Condition="'$(iOSLikeDedup)' == 'true'">
+      <_iOSLikeDedupAssembly>$(MSBuildThisFileDirectory)$(PublishDir)\aot-instances.dll</_iOSLikeDedupAssembly>
+    </PropertyGroup>
+    <WriteLinesToFile Condition="'$(iOSLikeDedup)' == 'true'" File="$(MSBuildThisFileDirectory)$(PublishDir)/aot-instances.cs" Overwrite="true" Lines="" WriteOnlyWhenDifferent="true" />
+    <Csc Condition="'$(iOSLikeDedup)' == 'true'"
+      Sources="$(MSBuildThisFileDirectory)$(PublishDir)\aot-instances.cs"
+      OutputAssembly="$(_iOSLikeDedupAssembly)"
+      TargetType="library"
+      Deterministic="true"
+      References="@(ReferencePath)"
+      ToolExe="$(CscToolExe)"
+      ToolPath="$(CscToolPath)" />
+
     <ItemGroup>
       <BundleAssemblies Condition="'$(RunAOTCompilation)' != 'true'" Include="$(MSBuildThisFileDirectory)$(PublishDir)\*.dll" />
       <AotInputAssemblies Condition="'$(RunAOTCompilation)' == 'true'" Include="$(MSBuildThisFileDirectory)$(PublishDir)\*.dll">
@@ -62,6 +76,7 @@
         Mode="$(AOTMode)"
         OutputType="AsmOnly"
         Assemblies="@(AotInputAssemblies)"
+        DedupAssembly="$(_iOSLikeDedupAssembly)"
         AotModulesTablePath="$(AppDir)\modules.m"
         AotModulesTableLanguage="ObjC"
         OutputDir="$(PublishDir)"