[experiment] On-device decompressed AssemblyStore cache (CoreCLR)

Documentation/building/configuration.md

@@ -118,6 +118,12 @@ Overridable MSBuild properties include:
      assemblies placed in the APK will be compressed in `Release` builds. `Debug`
      builds are not affected.
 
+  * `$(AndroidEnableAssemblyStoreDecompressionCache)`: Defaults to `False`. When
+     enabled for a CoreCLR `Release` build, decompressed assemblies are cached in
+     the app's Android code-cache directory and mapped from there on subsequent
+     launches. The cache consumes additional on-device storage and is rebuilt
+     after app or platform updates.
+
 ## Options suitable for local development
 
 ### Native runtime (`src/native`)

Documentation/project-docs/AssemblyStores.md

@@ -97,6 +97,7 @@ The header is a fixed-size structure at the beginning of each assembly store fil
 - **ENTRY_COUNT** (`uint32_t`) - Number of assemblies in the store
 - **INDEX_ENTRY_COUNT** (`uint32_t`) - Number of entries in the index (typically `ENTRY_COUNT * 2`)
 - **INDEX_SIZE** (`uint32_t`) - Index size in bytes
+- **CONTENT_ID** (`uint64_t`) - Deterministic xxHash3 of everything after the header
 
 ## [INDEX]
 
@@ -154,6 +155,7 @@ All kinds of stores share the following header format:
         uint32_t entry_count;
         uint32_t index_entry_count;
         uint32_t index_size; // index size in bytes
+        uint64_t content_id;
     };
 
 Individual fields have the following meanings:
@@ -165,6 +167,7 @@ Individual fields have the following meanings:
    table, see below)
  - `index_entry_count`: number of entries in the index
  - `index_size`: index size in bytes
+ - `content_id`: deterministic xxHash3 of the index, descriptors, names, and assembly data
 
 ## Assembly descriptor table
 
@@ -252,6 +255,7 @@ struct [[gnu::packed]] AssemblyStoreHeader final
     uint32_t entry_count;
     uint32_t index_entry_count;
     uint32_t index_size; // index size in bytes
+    uint64_t content_id;
 };
 ```
 

src/Xamarin.Android.Build.Tasks/Tasks/GenerateNativeApplicationConfigSources.cs

@@ -59,6 +59,7 @@ public class GenerateNativeApplicationConfigSources : AndroidTask
 
 		public bool EnableMarshalMethods { get; set; }
 		public bool EnableManagedMarshalMethodsLookup { get; set; }
+		public bool AndroidEnableAssemblyStoreDecompressionCache { get; set; }
 		public string? RuntimeConfigBinFilePath { get; set; }
 		public string ProjectRuntimeConfigFilePath { get; set; } = String.Empty;
 		public string? BoundExceptionType { get; set; }
@@ -285,6 +286,7 @@ static bool ShouldSkipAssembly (ITaskItem assembly)
 					MarshalMethodsEnabled = EnableMarshalMethods,
 					ManagedMarshalMethodsLookupEnabled = EnableManagedMarshalMethodsLookup,
 					IgnoreSplitConfigs = ShouldIgnoreSplitConfigs (),
+					AssemblyStoreDecompressionCacheEnabled = AndroidEnableAssemblyStoreDecompressionCache,
 				};
 			} else {
 				appConfigAsmGen = new ApplicationConfigNativeAssemblyGenerator (envBuilder.EnvironmentVariables, envBuilder.SystemProperties, Log) {

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/CreateAssemblyStoreTests.cs

@@ -0,0 +1,57 @@
+#nullable enable
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.IO.Hashing;
+using System.Linq;
+
+using Microsoft.Build.Framework;
+using Microsoft.Build.Utilities;
+using NUnit.Framework;
+using Xamarin.Android.Tasks;
+
+namespace Xamarin.Android.Build.Tests.Tasks;
+
+[TestFixture]
+public class CreateAssemblyStoreTests : BaseTest
+{
+	[Test]
+	public void ContentIdMatchesStoreContents ()
+	{
+		string testDirectory = Path.Combine (Root, "temp", nameof (ContentIdMatchesStoreContents));
+		Directory.CreateDirectory (testDirectory);
+
+		string assemblyPath = Path.Combine (testDirectory, "Example.dll.zst");
+		byte [] assemblyData = [1, 3, 3, 7, 9, 11, 17, 23];
+		File.WriteAllBytes (assemblyPath, assemblyData);
+
+		var metadata = new Dictionary<string, string> {
+			["Abi"] = "arm64-v8a",
+		};
+		var task = new CreateAssemblyStore {
+			BuildEngine = new MockBuildEngine (TestContext.Out),
+			AppSharedLibrariesDir = Path.Combine (testDirectory, "stores"),
+			ResolvedFrameworkAssemblies = [],
+			ResolvedUserAssemblies = [new TaskItem (assemblyPath, metadata)],
+			SupportedAbis = ["arm64-v8a"],
+			TargetRuntime = "CoreCLR",
+			UseAssemblyStore = true,
+		};
+
+		Assert.IsTrue (task.Execute (), "CreateAssemblyStore should succeed.");
+
+		string storePath = task.AssembliesToAddToArchive.Single ().ItemSpec;
+		byte [] store = File.ReadAllBytes (storePath);
+		using var reader = new BinaryReader (new MemoryStream (store));
+		Assert.AreEqual (0x41424158u, reader.ReadUInt32 (), "Unexpected assembly store magic.");
+		Assert.AreEqual (0x80010004u, reader.ReadUInt32 (), "Unexpected arm64 assembly store version.");
+		reader.BaseStream.Seek (3 * sizeof (uint), SeekOrigin.Current);
+		ulong contentId = reader.ReadUInt64 ();
+
+		Assert.AreEqual (
+			XxHash3.HashToUInt64 (store.AsSpan (5 * sizeof (uint) + sizeof (ulong))),
+			contentId,
+			"The content ID should hash everything after the assembly store header."
+		);
+	}
+}

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Tasks/GenerateNativeApplicationConfigSourcesTests.cs

@@ -0,0 +1,46 @@
+#nullable enable
+using System.IO;
+
+using Microsoft.Build.Utilities;
+using NUnit.Framework;
+using Xamarin.Android.Tasks;
+using Xamarin.ProjectTools;
+
+namespace Xamarin.Android.Build.Tests.Tasks;
+
+[TestFixture]
+public class GenerateNativeApplicationConfigSourcesTests : BaseTest
+{
+	[TestCase (false)]
+	[TestCase (true)]
+	public void AssemblyStoreDecompressionCacheSettingIsEmitted (bool enabled)
+	{
+		string outputRoot = Path.Combine (Root, "temp", $"{nameof (AssemblyStoreDecompressionCacheSettingIsEmitted)}-{enabled}");
+		string monoAndroidPath = Path.Combine (TestEnvironment.MonoAndroidFrameworkDirectory, "Mono.Android.dll");
+		FileAssert.Exists (monoAndroidPath);
+
+		var task = new GenerateNativeApplicationConfigSources {
+			BuildEngine = new MockBuildEngine (TestContext.Out),
+			ResolvedAssemblies = [new TaskItem (monoAndroidPath)],
+			EnvironmentOutputDirectory = Path.Combine (outputRoot, "android"),
+			SupportedAbis = ["arm64-v8a"],
+			AndroidPackageName = "com.microsoft.android.cachetest",
+			EnablePreloadAssembliesDefault = false,
+			TargetsCLR = true,
+			AndroidRuntime = "CoreCLR",
+			UseAssemblyStore = true,
+			AndroidEnableAssemblyStoreDecompressionCache = enabled,
+		};
+
+		Assert.IsTrue (task.Execute (), "GenerateNativeApplicationConfigSources should succeed.");
+
+		var environmentFiles = EnvironmentHelper.GatherEnvironmentFiles (
+			outputRoot,
+			"arm64-v8a",
+			required: true,
+			runtime: AndroidRuntime.CoreCLR
+		);
+		var config = (EnvironmentHelper.ApplicationConfig_CoreCLR)EnvironmentHelper.ReadApplicationConfig (environmentFiles, AndroidRuntime.CoreCLR);
+		Assert.AreEqual (enabled, config.assembly_store_decompression_cache_enabled);
+	}
+}

src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/Utilities/EnvironmentHelper.cs

@@ -62,9 +62,10 @@ public sealed class ApplicationConfig_CoreCLR : IApplicationConfig
 			public uint   jni_remapping_replacement_method_index_entry_count;
 			public string android_package_name = String.Empty;
 			public bool   managed_marshal_methods_lookup_enabled;
+			public bool   assembly_store_decompression_cache_enabled;
 		}
 
-		const uint ApplicationConfigFieldCount_CoreCLR = 20;
+		const uint ApplicationConfigFieldCount_CoreCLR = 21;
 
 		// This must be identical to the ApplicationConfig structure in src/native/mono/xamarin-app-stub/xamarin-app.hh
 		public sealed class ApplicationConfig_MonoVM : IApplicationConfig
@@ -407,6 +408,11 @@ static IApplicationConfig ReadApplicationConfig_CoreCLR (EnvironmentFile envFile
 						AssertFieldType (envFile.Path, parser.SourceFilePath, ".byte", field [0], item.LineNumber);
 						ret.managed_marshal_methods_lookup_enabled = ConvertFieldToBool ("managed_marshal_methods_lookup_enabled", envFile.Path, parser.SourceFilePath, item.LineNumber, field [1]);
 						break;
+
+					case 20: // assembly_store_decompression_cache_enabled: bool / .byte
+						AssertFieldType (envFile.Path, parser.SourceFilePath, ".byte", field [0], item.LineNumber);
+						ret.assembly_store_decompression_cache_enabled = ConvertFieldToBool ("assembly_store_decompression_cache_enabled", envFile.Path, parser.SourceFilePath, item.LineNumber, field [1]);
+						break;
 				}
 				fieldCount++;
 			}
@@ -771,6 +777,7 @@ static void AssertApplicationConfigIsIdentical (ApplicationConfig_CoreCLR firstA
 			Assert.AreEqual (firstAppConfig.environment_variable_count, secondAppConfig.environment_variable_count, $"Field 'environment_variable_count' has different value in environment file '{secondEnvFile}' than in environment file '{firstEnvFile}'");
 			Assert.AreEqual (firstAppConfig.system_property_count, secondAppConfig.system_property_count, $"Field 'system_property_count' has different value in environment file '{secondEnvFile}' than in environment file '{firstEnvFile}'");
 			Assert.AreEqual (firstAppConfig.android_package_name, secondAppConfig.android_package_name, $"Field 'android_package_name' has different value in environment file '{secondEnvFile}' than in environment file '{firstEnvFile}'");
+			Assert.AreEqual (firstAppConfig.assembly_store_decompression_cache_enabled, secondAppConfig.assembly_store_decompression_cache_enabled, $"Field 'assembly_store_decompression_cache_enabled' has different value in environment file '{secondEnvFile}' than in environment file '{firstEnvFile}'");
 		}
 
 		static void AssertApplicationConfigIsIdentical (ApplicationConfig_MonoVM firstAppConfig, string firstEnvFile, ApplicationConfig_MonoVM secondAppConfig, string secondEnvFile)

src/Xamarin.Android.Build.Tasks/Utilities/ApplicationConfigCLR.cs

@@ -51,4 +51,5 @@ sealed class ApplicationConfigCLR
 	public uint   jni_remapping_replacement_method_index_entry_count;
 	public string android_package_name = String.Empty;
 	public bool   managed_marshal_methods_lookup_enabled;
+	public bool   assembly_store_decompression_cache_enabled;
 }

src/Xamarin.Android.Build.Tasks/Utilities/ApplicationConfigNativeAssemblyGeneratorCLR.cs

@@ -287,6 +287,7 @@ sealed class DsoCacheState
 	public bool MarshalMethodsEnabled { get; set; }
 	public bool ManagedMarshalMethodsLookupEnabled { get; set; }
 	public bool IgnoreSplitConfigs { get; set; }
+	public bool AssemblyStoreDecompressionCacheEnabled { get; set; }
 
 	public ApplicationConfigNativeAssemblyGeneratorCLR (IDictionary<string, string> environmentVariables, IDictionary<string, string> systemProperties,
 		IDictionary<string, string>? runtimeProperties, TaskLoggingHelper log)
@@ -373,6 +374,7 @@ protected override void Construct (LlvmIrModule module)
 			jni_remapping_replacement_type_count = (uint)JniRemappingReplacementTypeCount,
 			jni_remapping_replacement_method_index_entry_count = (uint)JniRemappingReplacementMethodIndexEntryCount,
 			android_package_name = AndroidPackageName,
+			assembly_store_decompression_cache_enabled = AssemblyStoreDecompressionCacheEnabled,
 		};
 		application_config = new StructureInstance<ApplicationConfigCLR> (applicationConfigStructureInfo, app_cfg);
 		module.AddGlobalVariable ("application_config", application_config);

src/Xamarin.Android.Build.Tasks/Utilities/AssemblyStoreGenerator.Classes.cs

@@ -5,7 +5,7 @@ partial class AssemblyStoreGenerator
 {
 	sealed class AssemblyStoreHeader
 	{
-		public const uint NativeSize = 5 * sizeof (uint);
+		public const uint NativeSize = 5 * sizeof (uint) + sizeof (ulong);
 
 		public readonly uint magic = ASSEMBLY_STORE_MAGIC;
 		public readonly uint version;
@@ -14,17 +14,19 @@ sealed class AssemblyStoreHeader
 
 		// Index size in bytes
 		public readonly uint index_size;
+		public readonly ulong content_id;
 
-		public AssemblyStoreHeader (uint version, uint entry_count, uint index_entry_count, uint index_size)
+		public AssemblyStoreHeader (uint version, uint entry_count, uint index_entry_count, uint index_size, ulong content_id)
 		{
 			this.version = version;
 			this.entry_count = entry_count;
 			this.index_entry_count = index_entry_count;
 			this.index_size = index_size;
+			this.content_id = content_id;
 		}
 #if XABT_TESTS
-		public AssemblyStoreHeader (uint magic, uint version, uint entry_count, uint index_entry_count, uint index_size)
-			: this (version, entry_count, index_entry_count, index_size)
+		public AssemblyStoreHeader (uint magic, uint version, uint entry_count, uint index_entry_count, uint index_size, ulong content_id)
+			: this (version, entry_count, index_entry_count, index_size, content_id)
 		{
 			this.magic = magic;
 		}

src/Xamarin.Android.Build.Tasks/Utilities/AssemblyStoreGenerator.cs

@@ -2,6 +2,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.IO.Hashing;
 
 using Microsoft.Android.Build.Tasks;
 using Microsoft.Build.Utilities;
@@ -28,6 +29,7 @@ namespace Xamarin.Android.Tasks;
 //  [ENTRY_COUNT]        uint; number of entries in the store
 //  [INDEX_ENTRY_COUNT]  uint; number of entries in the index
 //  [INDEX_SIZE]         uint; index size in bytes
+//  [CONTENT_ID]         ulong: deterministic hash of everything after the header
 //
 // INDEX (variable size, HEADER.ENTRY_COUNT*2 entries, for assembly names with and without the extension)
 //  [NAME_HASH]          uint on 32-bit platforms, ulong on 64-bit platforms; xxhash of the assembly name
@@ -53,8 +55,8 @@ partial class AssemblyStoreGenerator
 	const uint ASSEMBLY_STORE_MAGIC = 0x41424158; // 'XABA', little-endian, must match the BUNDLED_ASSEMBLIES_BLOB_MAGIC native constant
 
 	// Bit 31 is set for 64-bit platforms, cleared for the 32-bit ones
-	const uint ASSEMBLY_STORE_FORMAT_VERSION_64BIT = 0x80000003; // Must match the ASSEMBLY_STORE_FORMAT_VERSION native constant
-	const uint ASSEMBLY_STORE_FORMAT_VERSION_32BIT = 0x00000003;
+	const uint ASSEMBLY_STORE_FORMAT_VERSION_64BIT = 0x80000004; // Must match the ASSEMBLY_STORE_FORMAT_VERSION native constant
+	const uint ASSEMBLY_STORE_FORMAT_VERSION_32BIT = 0x00000004;
 
 	const uint ASSEMBLY_STORE_ABI_AARCH64 = 0x00010000;
 	const uint ASSEMBLY_STORE_ABI_ARM = 0x00020000;
@@ -122,7 +124,7 @@ string Generate (string baseOutputDirectory, AndroidTargetArch arch, List<Assemb
 		ulong curPos = assemblyDataStart;
 
 		Directory.CreateDirectory (Path.GetDirectoryName (storePath));
-		using var fs = File.Open (storePath, FileMode.Create, FileAccess.Write, FileShare.Read);
+		using var fs = File.Open (storePath, FileMode.Create, FileAccess.ReadWrite, FileShare.Read);
 		fs.Seek ((long)curPos, SeekOrigin.Begin);
 
 		uint mappingIndex = 0;
@@ -157,7 +159,7 @@ string Generate (string baseOutputDirectory, AndroidTargetArch arch, List<Assemb
 		fs.Seek (0, SeekOrigin.Begin);
 
 		uint storeVersion = is64Bit ? ASSEMBLY_STORE_FORMAT_VERSION_64BIT : ASSEMBLY_STORE_FORMAT_VERSION_32BIT;
-		var header = new AssemblyStoreHeader (storeVersion | abiFlag, infoCount, (uint)index.Count, (uint)(index.Count * IndexEntrySize ()));
+		var header = new AssemblyStoreHeader (storeVersion | abiFlag, infoCount, (uint)index.Count, (uint)(index.Count * IndexEntrySize ()), content_id: 0);
 		using var writer = new BinaryWriter (fs);
 		WriteHeader (writer, header);
 
@@ -178,11 +180,33 @@ string Generate (string baseOutputDirectory, AndroidTargetArch arch, List<Assemb
 			throw new InvalidOperationException ($"Internal error: store '{storePath}' position is different than metadata size after header write");
 		}
 
+		writer.Flush ();
+		ulong contentId = ComputeContentId (fs);
+		header = new AssemblyStoreHeader (storeVersion | abiFlag, infoCount, (uint)index.Count, (uint)(index.Count * IndexEntrySize ()), contentId);
+		fs.Seek (0, SeekOrigin.Begin);
+		WriteHeader (writer, header);
+		writer.Flush ();
+		log.LogDebugMessage ($"Assembly store content ID: 0x{contentId:x16}");
+
 		return storePath;
 
 		uint IndexEntrySize () => is64Bit ? AssemblyStoreIndexEntry.NativeSize64 : AssemblyStoreIndexEntry.NativeSize32;
 	}
 
+	static ulong ComputeContentId (Stream stream)
+	{
+		stream.Seek (AssemblyStoreHeader.NativeSize, SeekOrigin.Begin);
+
+		var hash = new XxHash3 ();
+		byte [] buffer = new byte [64 * 1024];
+		int bytesRead;
+		while ((bytesRead = stream.Read (buffer, 0, buffer.Length)) > 0) {
+			hash.Append (buffer.AsSpan (0, bytesRead));
+		}
+
+		return hash.GetCurrentHashAsUInt64 ();
+	}
+
 	void CopyData (FileInfo? src, Stream dest, string storePath)
 	{
 		if (src == null) {
@@ -239,6 +263,7 @@ void WriteHeader (BinaryWriter writer, AssemblyStoreHeader header)
 		writer.Write (header.entry_count);
 		writer.Write (header.index_entry_count);
 		writer.Write (header.index_size);
+		writer.Write (header.content_id);
 	}
 #if XABT_TESTS
 	AssemblyStoreHeader ReadHeader (BinaryReader reader)
@@ -249,8 +274,9 @@ AssemblyStoreHeader ReadHeader (BinaryReader reader)
 		uint entry_count       = reader.ReadUInt32 ();
 		uint index_entry_count = reader.ReadUInt32 ();
 		uint index_size        = reader.ReadUInt32 ();
+		ulong content_id        = reader.ReadUInt64 ();
 
-		return new AssemblyStoreHeader (magic, version, entry_count, index_entry_count, index_size);
+		return new AssemblyStoreHeader (magic, version, entry_count, index_entry_count, index_size, content_id);
 	}
 #endif
 

src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets

@@ -166,6 +166,7 @@ Copyright (C) 2011-2012 Xamarin. All rights reserved.
 	<AndroidGenerateLayoutBindings Condition=" '$(AndroidGenerateLayoutBindings)' == '' ">False</AndroidGenerateLayoutBindings>
 	<AndroidFragmentType Condition=" '$(AndroidFragmentType)' == '' ">Android.App.Fragment</AndroidFragmentType>
 	<AndroidEnableAssemblyCompression Condition=" '$(AndroidEnableAssemblyCompression)' == '' ">True</AndroidEnableAssemblyCompression>
+	<AndroidEnableAssemblyStoreDecompressionCache Condition=" '$(AndroidEnableAssemblyStoreDecompressionCache)' == '' ">False</AndroidEnableAssemblyStoreDecompressionCache>
 	<AndroidIncludeWrapSh Condition=" '$(AndroidIncludeWrapSh)' == '' ">False</AndroidIncludeWrapSh>
 	<_AndroidCheckedBuild Condition=" '$(_AndroidCheckedBuild)' == '' "></_AndroidCheckedBuild>
 
@@ -1802,6 +1803,7 @@ because xbuild doesn't support framework reference assemblies.
       BoundExceptionType="$(AndroidBoundExceptionType)"
       RuntimeConfigBinFilePath="$(_BinaryRuntimeConfigPath)"
       UseAssemblyStore="$(_AndroidUseAssemblyStore)"
+      AndroidEnableAssemblyStoreDecompressionCache="$(AndroidEnableAssemblyStoreDecompressionCache)"
       EnableMarshalMethods="$(_AndroidUseMarshalMethods)"
       EnableManagedMarshalMethodsLookup="$(_AndroidUseManagedMarshalMethodsLookup)"
       CustomBundleConfigFile="$(AndroidBundleConfigurationFile)"

src/java-runtime/java/mono/android/clr/MonoPackageManager.java

@@ -52,6 +52,7 @@ public static void LoadApplication (Context context)
 				String language     = locale.getLanguage () + "-" + locale.getCountry ();
 				String filesDir     = context.getFilesDir ().getAbsolutePath ();
 				String cacheDir     = context.getCacheDir ().getAbsolutePath ();
+				String codeCacheDir = context.getCodeCacheDir ().getAbsolutePath ();
 				String dataDir      = getNativeLibraryPath (context);
 				ClassLoader loader  = context.getClassLoader ();
 				String runtimeDir   = getNativeLibraryPath (runtimePackage);
@@ -66,7 +67,7 @@ public static void LoadApplication (Context context)
 				//
 				// Should the order change here, src/native/clr/include/constants.hh must be updated accordingly
 				//
-				String[] appDirs = new String[] {filesDir, cacheDir, dataDir};
+				String[] appDirs = new String[] {filesDir, cacheDir, dataDir, codeCacheDir};
 				boolean haveSplitApks = runtimePackage.splitSourceDirs != null && runtimePackage.splitSourceDirs.length > 0;
 
 				System.loadLibrary("monodroid");