[msbuild] Generate C code for runtimeconfig properties (CoreCLR). Fixes #26334

dotnet/targets/Xamarin.Shared.Sdk.targets

@@ -467,8 +467,10 @@
 		DependsOnTargets="_RunRidSpecificBuild"
 		>
 		<ItemGroup>
-			<!-- If we're creating a runtimeconfig.json file, then the resulting binary runtimeconfig.bin file can be put in the architecture-specific subdirectory -->
-			<_ArchitectureSpecificFiles Include="$(_RuntimeConfigurationFile)" Condition="'$(GenerateRuntimeConfigurationFiles)' != ''" />
+			<!-- If we're creating a runtimeconfig.json file, then the resulting binary runtimeconfig.bin file can be put in the architecture-specific subdirectory.
+			     Only MonoVM ships this file; CoreCLR bakes the runtime configuration into the app as C code, and
+			     NativeAOT embeds it into the executable at publish time (neither reads runtimeconfig.bin). -->
+			<_ArchitectureSpecificFiles Include="$(_RuntimeConfigurationFile)" Condition="'$(GenerateRuntimeConfigurationFiles)' != '' And '$(_XamarinRuntime)' == 'MonoVM'" />
 		</ItemGroup>
 
 		<MergeAppBundles
@@ -733,6 +735,13 @@
 			<!-- Set default ValidateObjectPointers value -->
 			<_ValidateObjectPointers Condition="'$(_ValidateObjectPointers)' == ''">false</_ValidateObjectPointers>
 
+			<!-- Only MonoVM ships the binary runtimeconfig format and reads it at startup (locating it by name
+			     via RuntimeConfigurationFile). CoreCLR bakes the runtime configuration into the app as C code
+			     (from the merged json, handed to the linker via RuntimeConfigurationFilePath), and NativeAOT
+			     embeds it into the executable at publish time - neither ships nor reads a runtimeconfig file. -->
+			<_BundlerRuntimeConfigurationFile Condition="'$(_XamarinRuntime)' == 'MonoVM'">$(_RuntimeConfigurationFile)</_BundlerRuntimeConfigurationFile>
+			<_BundlerRuntimeConfigurationFilePath Condition="'$(_XamarinRuntime)' == 'CoreCLR' And '$(GenerateRuntimeConfigurationFiles)' == 'true'">$(_MergedRuntimeConfigFilePath)</_BundlerRuntimeConfigurationFilePath>
+
 			<_CustomLinkerOptions>
 				AreAnyAssembliesTrimmed=$(_AreAnyAssembliesTrimmed)
 				AssemblyName=$(AssemblyName).dll
@@ -782,7 +791,8 @@
 				@(ReferenceNativeSymbol -> 'ReferenceNativeSymbol=%(SymbolType):%(SymbolMode):%(Identity)')
 				RequireLinkWithAttributeForObjectiveCClassSearch=$(RequireLinkWithAttributeForObjectiveCClassSearch)
 				RequirePInvokeWrappers=$(_RequirePInvokeWrappers)
-				RuntimeConfigurationFile=$(_RuntimeConfigurationFile)
+				RuntimeConfigurationFile=$(_BundlerRuntimeConfigurationFile)
+				RuntimeConfigurationFilePath=$(_BundlerRuntimeConfigurationFilePath)
 				SdkDevPath=$(_SdkDevPath)
 				SdkRootDirectory=$(_XamarinSdkRootDirectory)
 				SdkVersion=$(_SdkVersion)
@@ -1564,6 +1574,9 @@
 
 			<_RuntimeConfigurationFile>runtimeconfig.bin</_RuntimeConfigurationFile>
 
+			<!-- The runtimeconfig.json merged with the companion runtimeconfig.dev.json (see _CreateRuntimeConfiguration). -->
+			<_MergedRuntimeConfigFilePath>$(DeviceSpecificIntermediateOutputPath)runtimeconfig.merged.json</_MergedRuntimeConfigFilePath>
+
 			<!-- Path to the file where Objective-C type map information is stored -->
 			<_TypeMapFilePath Condition="'$(_TypeMapFilePath)' == ''">$(_LinkerCacheDirectory)/type-map.txt</_TypeMapFilePath>
 
@@ -1595,12 +1608,9 @@
 
 	<Target Name="_CreateRuntimeConfiguration"
 		Inputs="$(ProjectRuntimeConfigFilePath);$(ProjectRuntimeConfigDevFilePath)"
-		Outputs="$(_ParsedRuntimeConfigFilePath)"
+		Outputs="$(_RuntimeConfigurationOutputFile)"
 		DependsOnTargets="GenerateBuildRuntimeConfigurationFiles;_ComputePublishLocation"
 		>
-		<PropertyGroup>
-			<_MergedRuntimeConfigFilePath>$(DeviceSpecificIntermediateOutputPath)runtimeconfig.merged.json</_MergedRuntimeConfigFilePath>
-		</PropertyGroup>
 		<ItemGroup>
 			<!-- List all the properties passed to xamarin_bridge_vm_initialize in xamarin_vm_initialize (in runtime.m) -->
 			<_RuntimeConfigReservedProperties Include="APP_PATHS" />
@@ -1629,7 +1639,7 @@
 		</ItemGroup>
 
 		<RuntimeConfigParserTask
-			Condition="'$(GenerateRuntimeConfigurationFiles)' == 'true'"
+			Condition="'$(GenerateRuntimeConfigurationFiles)' == 'true' And '$(_XamarinRuntime)' == 'MonoVM'"
 			RuntimeConfigFile="$(_MergedRuntimeConfigFilePath)"
 			OutputFile="$(_ParsedRuntimeConfigFilePath)"
 			RuntimeConfigReservedProperties="@(_RuntimeConfigReservedProperties)"
@@ -2543,10 +2553,17 @@
 			<_DylibPublishDir Condition="'$(SdkIsMobile)' == 'true'">$(_RelativeAppBundlePath)\</_DylibPublishDir>
 			<_DylibPublishDir Condition="'$(SdkIsDesktop)' == 'true'">$(_RelativeAppBundlePath)\Contents\$(_CustomBundleName)\</_DylibPublishDir>
 			<_ParsedRuntimeConfigFilePath Condition="'$(_ParsedRuntimeConfigFilePath)' == ''">$(DeviceSpecificIntermediateOutputPath)$(_RuntimeConfigurationFile)</_ParsedRuntimeConfigFilePath>
+
+			<!-- The final output of _CreateRuntimeConfiguration: only MonoVM ships the binary runtimeconfig format;
+			     CoreCLR and NativeAOT use the merged json instead (baked into the app as C code by the linker for
+			     CoreCLR, embedded into the executable at publish time for NativeAOT). -->
+			<_RuntimeConfigurationOutputFile Condition="'$(_XamarinRuntime)' != 'MonoVM'">$(_MergedRuntimeConfigFilePath)</_RuntimeConfigurationOutputFile>
+			<_RuntimeConfigurationOutputFile Condition="'$(_RuntimeConfigurationOutputFile)' == ''">$(_ParsedRuntimeConfigFilePath)</_RuntimeConfigurationOutputFile>
 		</PropertyGroup>
 		<ItemGroup>
-			<!-- Add runtimeconfig.bin to ResolvedFileToPublish so we process it in ComputeBundlePath and copy the file to the app bundle -->
-			<ResolvedFileToPublish Include="$(_ParsedRuntimeConfigFilePath)" Condition="'$(GenerateRuntimeConfigurationFiles)' == 'true'">
+			<!-- Add runtimeconfig.bin to ResolvedFileToPublish so we process it in ComputeBundlePath and copy the file to the app bundle.
+			     Only MonoVM ships this file (CoreCLR bakes the configuration into the app as C code, NativeAOT embeds it at publish time). -->
+			<ResolvedFileToPublish Include="$(_ParsedRuntimeConfigFilePath)" Condition="'$(GenerateRuntimeConfigurationFiles)' == 'true' And '$(_XamarinRuntime)' == 'MonoVM'">
 				<RelativePath>$([System.IO.Path]::GetFileName('$(_ParsedRuntimeConfigFilePath)'))</RelativePath>
 				<PublishFolderType>Assembly</PublishFolderType>
 				<CopyToPublishDirectory>PreserveNewest</CopyToPublishDirectory>

runtime/coreclr-bridge.m

@@ -8,10 +8,8 @@
 
 #if defined (CORECLR_RUNTIME)
 
-#include <sys/stat.h>
 #include <inttypes.h>
 #include <pthread.h>
-#include <sys/mman.h>
 
 #include "product.h"
 #include "runtime-internal.h"
@@ -361,104 +359,29 @@
 }
 
 /**
- * xamarin_bridge_decode_value:
- * 
- * This implementation is a slightly modified copy (to make it compile) of mono_metadata_decode_value
- * https://github.com/dotnet/runtime/blob/08a7b2382799082eedb94d70fca6c66eb75f2872/src/mono/mono/metadata/metadata.c#L1525
+ * The runtimeconfig.json 'configProperties' are baked into the app as C arrays at build time
+ * (see the generated main and Xamarin.Shared.Sdk.targets), and made available here through the
+ * xamarin_runtime_config_property_* globals. This is simpler than the mobile-runtimeconfig binary
+ * format used by MonoVM: no separate file to ship, mmap and decode at startup.
  */
-guint32
-xamarin_bridge_decode_value (const char *_ptr, const char **rptr)
-{
-	const unsigned char *ptr = (const unsigned char *) _ptr;
-	unsigned char b = *ptr;
-	guint32 len;
-
-	if ((b & 0x80) == 0){
-		len = b;
-		++ptr;
-	} else if ((b & 0x40) == 0){
-		len = (guint32) ((b & 0x3f) << 8 | ptr [1]);
-		ptr += 2;
-	} else {
-		len = (guint32) (((b & 0x1f) << 24) |
-			(ptr [1] << 16) |
-			(ptr [2] << 8) |
-			ptr [3]);
-		ptr += 4;
-	}
-	if (rptr)
-		*rptr = (char*)ptr;
-
-	return len;
-}
-
-static char *
-xamarin_read_config_string (const char **buf)
-{
-		guint32 configLength = xamarin_bridge_decode_value (*buf, buf);
-		char *value = strndup (*buf, configLength);
-		*buf = *buf + configLength;
-		return value;
-}
-
-static void *
-xamarin_mmap_runtime_config_file (size_t *length)
-{
-	if (xamarin_runtime_configuration_name == NULL) {
-		LOG (PRODUCT ": No runtime config file provided at build time.\n");
-		return NULL;
-	}
-
-	char path [1024];
-	if (!xamarin_locate_app_resource (xamarin_runtime_configuration_name, path, sizeof (path))) {
-		LOG (PRODUCT ": Could not locate the runtime config file '%s' in the app bundle.\n", xamarin_runtime_configuration_name);
-		return NULL;
-	}
-
-	int fd = open (path, O_RDONLY);
-	if (fd == -1) {
-		LOG (PRODUCT ": Could not open the runtime config file '%s' in the app bundle: %s\n", path, strerror (errno));
-		return NULL;
-	}
-
-	struct stat stat_buf = { };
-	if (fstat (fd, &stat_buf) == -1) {
-		LOG (PRODUCT ": Could not stat the runtime config file '%s' in the app bundle: %s\n", path, strerror (errno));
-		close (fd);
-		return NULL;
-	}
-
-	*length = (size_t) stat_buf.st_size;
-	void *buffer = mmap (NULL, *length, PROT_READ, MAP_PRIVATE, fd, 0);
-	close (fd);
-	return buffer;
-}
 
 // Input: the property keys + values passed to xamarin_bridge_vm_initialize
-// Output: newly allocated arrays of property keys + values that include those passed to xamarin_bridge_vm_initialize together with those in the runtimeconfig.bin file
+// Output: newly allocated arrays of property keys + values that include those passed to xamarin_bridge_vm_initialize together with those baked into the app from the runtimeconfig.json file
 // Caller must free the allocated arrays + their elements
 void
 xamarin_bridge_compute_properties (int inputCount, const char **inputKeys, const char **inputValues, int* outputCount, const char ***outputKeys, const char ***outputValues)
 {
-	size_t fd_len = 0;
-	const char *buf = (const char *) xamarin_mmap_runtime_config_file (&fd_len);
-	int runtimeConfigCount = 0;
-
-	if (buf != NULL)
-		runtimeConfigCount = (int) xamarin_bridge_decode_value (buf, &buf);
+	int runtimeConfigCount = xamarin_runtime_config_property_count;
 
 	// Allocate the output arrays
 	*outputCount = inputCount + runtimeConfigCount;
 	*outputKeys = (const char **) calloc ((size_t) *outputCount, sizeof (char *));
 	*outputValues = (const char **) calloc ((size_t) *outputCount, sizeof (char *));
 
-	// Read the runtimeconfig properties
-	// https://github.com/dotnet/runtime/blob/57bfe474518ab5b7cfe6bf7424a79ce3af9d6657/docs/design/mono/mobile-runtimeconfig-json.md#the-encoded-runtimeconfig-format
+	// Copy the runtimeconfig properties baked into the app
 	for (int i = 0; i < runtimeConfigCount; i++) {
-		char *key = xamarin_read_config_string (&buf);
-		char *value = xamarin_read_config_string (&buf);
-		(*outputKeys) [i] = key;
-		(*outputValues) [i] = value;
+		(*outputKeys) [i] = strdup (xamarin_runtime_config_property_keys [i]);
+		(*outputValues) [i] = strdup (xamarin_runtime_config_property_values [i]);
 	}
 
 	// Copy the input properties
@@ -470,9 +393,6 @@
 			NSLog (@PRODUCT ": No name/value specified for runtime property %s=%s", inputKeys [i], inputValues [i]);
 		}
 	}
-
-	if (buf != NULL)
-		munmap ((void *) buf, fd_len);
 }
 
 #if !defined (NATIVEAOT)

runtime/runtime.m

@@ -75,6 +75,13 @@
 #endif
 const char *xamarin_runtime_configuration_name = NULL;
 
+// The runtimeconfig.json 'configProperties' baked into the app as C arrays (CoreCLR only).
+// These are set from the generated main (xamarin_setup_impl) and consumed by
+// xamarin_bridge_compute_properties when initializing CoreCLR.
+int xamarin_runtime_config_property_count = 0;
+const char **xamarin_runtime_config_property_keys = NULL;
+const char **xamarin_runtime_config_property_values = NULL;
+
 enum XamarinNativeLinkMode xamarin_libmono_native_link_mode = XamarinNativeLinkModeStaticObject;
 const char **xamarin_runtime_libraries = NULL;
 

runtime/xamarin/main.h

@@ -125,6 +125,9 @@ extern enum XamarinLaunchMode xamarin_launch_mode;
 extern bool xamarin_supports_dynamic_registration;
 #endif
 extern const char *xamarin_runtime_configuration_name;
+extern int xamarin_runtime_config_property_count;
+extern const char **xamarin_runtime_config_property_keys;
+extern const char **xamarin_runtime_config_property_values;
 extern enum XamarinNativeLinkMode xamarin_libmono_native_link_mode;
 extern const char** xamarin_runtime_libraries;
 

tests/dotnet/UnitTests/BundleStructureTest.cs

@@ -322,7 +322,9 @@ internal static void CheckAppBundleContents (ApplePlatform platform, IEnumerable
 			expectedFiles.Add (Path.Combine (assemblyDirectory, "Mono.Options.dll"));
 			AddMultiRidAssembly (platform, expectedFiles, assemblyDirectory, "Touch.Client", runtimeIdentifiers, platform == ApplePlatform.MacOSX || (platform == ApplePlatform.MacCatalyst && !isReleaseBuild), includeDebugFiles: includeDebugFiles);
 			AddMultiRidAssembly (platform, expectedFiles, assemblyDirectory, Path.GetFileNameWithoutExtension (Configuration.GetBaseLibraryName (platform)), runtimeIdentifiers, platform == ApplePlatform.MacOSX, includeDebugFiles: includeDebugFiles);
-			expectedFiles.Add (Path.Combine (assemblyDirectory, "runtimeconfig.bin"));
+			// For CoreCLR the runtime configuration is baked into the app as C code, so there's no runtimeconfig.bin file.
+			if (!isCoreCLR)
+				expectedFiles.Add (Path.Combine (assemblyDirectory, "runtimeconfig.bin"));
 
 			switch (platform) {
 			case ApplePlatform.iOS:

tests/dotnet/UnitTests/RuntimeConfigurationTest.cs

@@ -0,0 +1,47 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.IO;
+using System.Linq;
+
+#nullable enable
+
+namespace Xamarin.Tests {
+	[TestFixture]
+	public class RuntimeConfigurationTest : TestBaseClass {
+		[Test]
+		[TestCase (ApplePlatform.MacOSX, "osx-arm64")]
+		public void BakedIntoGeneratedMain (ApplePlatform platform, string runtimeIdentifiers)
+		{
+			// For CoreCLR the runtimeconfig.json 'configProperties' are baked into the app as C arrays in the
+			// generated main (and assigned to the xamarin_runtime_config_property_* globals), instead of shipping
+			// the binary runtimeconfig format and decoding it at startup. Here we build an app with a well-known
+			// config property (System.Globalization.Invariant, from InvariantGlobalization) and verify both that
+			// it ends up in the generated main and that there's no runtimeconfig.bin in the app bundle.
+			var project = "MySimpleApp";
+			Configuration.IgnoreIfIgnoredPlatform (platform);
+			Configuration.AssertRuntimeIdentifiersAvailable (platform, runtimeIdentifiers);
+
+			var project_path = GetProjectPath (project, platform: platform);
+			Clean (project_path);
+			var properties = GetDefaultProperties (runtimeIdentifiers);
+			properties ["InvariantGlobalization"] = "true";
+
+			DotNet.AssertBuild (project_path, properties);
+
+			var objDir = GetObjDir (project_path, platform, runtimeIdentifiers);
+			var generatedMains = Directory.GetFiles (objDir, "main.*.mm", SearchOption.AllDirectories);
+			Assert.That (generatedMains, Is.Not.Empty, "A generated main.mm must exist.");
+
+			foreach (var main in generatedMains) {
+				var contents = File.ReadAllText (main);
+				Assert.That (contents, Does.Contain ("xamarin_runtime_config_property_keys_array"), $"The generated main '{main}' must bake the runtime configuration properties.");
+				Assert.That (contents, Does.Contain ("\"System.Globalization.Invariant\""), $"The generated main '{main}' must contain the System.Globalization.Invariant property.");
+			}
+
+			var appPath = GetAppPath (project_path, platform, runtimeIdentifiers);
+			var runtimeConfigBin = Directory.GetFiles (appPath, "runtimeconfig.bin", SearchOption.AllDirectories);
+			Assert.That (runtimeConfigBin, Is.Empty, "No runtimeconfig.bin should be shipped for CoreCLR (the configuration is baked into the app).");
+		}
+	}
+}

tests/dotnet/UnitTests/expected/MacCatalyst-NativeAOT-TrimmableStatic-size.txt

@@ -4,7 +4,5 @@ Contents/Info.plist:
     1,062 bytes (1.0 KB = 0.0 MB)
 Contents/MacOS/SizeTestApp:
     8,785,672 bytes (8,579.8 KB = 8.4 MB)
-Contents/MonoBundle/runtimeconfig.bin:
-    1,896 bytes (1.9 KB = 0.0 MB)
 Contents/PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)

tests/dotnet/UnitTests/expected/MacCatalyst-NativeAOT-size.txt

@@ -4,7 +4,5 @@ Contents/Info.plist:
     1,062 bytes (1.0 KB = 0.0 MB)
 Contents/MacOS/SizeTestApp:
     2,739,336 bytes (2,675.1 KB = 2.6 MB)
-Contents/MonoBundle/runtimeconfig.bin:
-    1,808 bytes (1.8 KB = 0.0 MB)
 Contents/PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)

tests/dotnet/UnitTests/expected/MacOSX-CoreCLR-Interpreter-TrimmableStatic-size.txt

@@ -734,7 +734,5 @@ Contents/MonoBundle/libSystem.Net.Security.Native.dylib:
     151,904 bytes (148.3 KB = 0.1 MB)
 Contents/MonoBundle/libSystem.Security.Cryptography.Native.Apple.dylib:
     347,888 bytes (339.7 KB = 0.3 MB)
-Contents/MonoBundle/runtimeconfig.bin:
-    1,445 bytes (1.4 KB = 0.0 MB)
 Contents/PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)

tests/dotnet/UnitTests/expected/MacOSX-CoreCLR-Interpreter-size.txt

@@ -726,7 +726,5 @@ Contents/MonoBundle/libSystem.Net.Security.Native.dylib:
     151,904 bytes (148.3 KB = 0.1 MB)
 Contents/MonoBundle/libSystem.Security.Cryptography.Native.Apple.dylib:
     347,888 bytes (339.7 KB = 0.3 MB)
-Contents/MonoBundle/runtimeconfig.bin:
-    1,363 bytes (1.3 KB = 0.0 MB)
 Contents/PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)

tests/dotnet/UnitTests/expected/MacOSX-NativeAOT-TrimmableStatic-size.txt

@@ -14,7 +14,5 @@ Contents/MonoBundle/libSystem.Net.Security.Native.dylib:
     151,904 bytes (148.3 KB = 0.1 MB)
 Contents/MonoBundle/libSystem.Security.Cryptography.Native.Apple.dylib:
     333,152 bytes (325.3 KB = 0.3 MB)
-Contents/MonoBundle/runtimeconfig.bin:
-    1,848 bytes (1.8 KB = 0.0 MB)
 Contents/PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)

tests/dotnet/UnitTests/expected/MacOSX-NativeAOT-size.txt

@@ -14,7 +14,5 @@ Contents/MonoBundle/libSystem.Net.Security.Native.dylib:
     151,904 bytes (148.3 KB = 0.1 MB)
 Contents/MonoBundle/libSystem.Security.Cryptography.Native.Apple.dylib:
     333,152 bytes (325.3 KB = 0.3 MB)
-Contents/MonoBundle/runtimeconfig.bin:
-    1,766 bytes (1.7 KB = 0.0 MB)
 Contents/PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)

tests/dotnet/UnitTests/expected/TVOS-NativeAOT-TrimmableStatic-size.txt

@@ -4,7 +4,5 @@ Info.plist:
     1,128 bytes (1.1 KB = 0.0 MB)
 PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)
-runtimeconfig.bin:
-    1,889 bytes (1.8 KB = 0.0 MB)
 SizeTestApp:
     7,801,720 bytes (7,618.9 KB = 7.4 MB)

tests/dotnet/UnitTests/expected/TVOS-NativeAOT-size.txt

@@ -4,7 +4,5 @@ Info.plist:
     1,128 bytes (1.1 KB = 0.0 MB)
 PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)
-runtimeconfig.bin:
-    1,808 bytes (1.8 KB = 0.0 MB)
 SizeTestApp:
     2,702,696 bytes (2,639.4 KB = 2.6 MB)

tests/dotnet/UnitTests/expected/iOS-NativeAOT-TrimmableStatic-size.txt

@@ -4,7 +4,5 @@ Info.plist:
     1,152 bytes (1.1 KB = 0.0 MB)
 PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)
-runtimeconfig.bin:
-    1,888 bytes (1.8 KB = 0.0 MB)
 SizeTestApp:
     8,995,264 bytes (8,784.4 KB = 8.6 MB)

tests/dotnet/UnitTests/expected/iOS-NativeAOT-size.txt

@@ -4,7 +4,5 @@ Info.plist:
     1,152 bytes (1.1 KB = 0.0 MB)
 PkgInfo:
     8 bytes (0.0 KB = 0.0 MB)
-runtimeconfig.bin:
-    1,808 bytes (1.8 KB = 0.0 MB)
 SizeTestApp:
     2,703,032 bytes (2,639.7 KB = 2.6 MB)