[mono] Implement AssemblyExtensions.TryGetRawMetadata. (#111642)

---------

Co-authored-by: Larry Ewing <[email protected]>
Co-authored-by: Jan Kotas <[email protected]>

Author: 3 people

src/libraries/System.Runtime.Loader/tests/AssemblyExtensionsTest.cs

@@ -12,7 +12,7 @@ public unsafe class AssemblyExtensionsTest
         [Fact]
         public void TryGetRawMetadata()
         {
-            bool supportsRawMetadata = PlatformDetection.IsNotMonoRuntime && PlatformDetection.IsNotNativeAot;
+            bool supportsRawMetadata = PlatformDetection.IsNotNativeAot;
 
             Assembly assembly = typeof(AssemblyExtensionsTest).Assembly;
             bool hasMetadata = assembly.TryGetRawMetadata(out byte* blob, out int length);

src/mono/System.Private.CoreLib/src/System/Reflection/Metadata/AssemblyExtensions.cs

@@ -12,6 +12,11 @@ public static unsafe bool TryGetRawMetadata(this Assembly assembly, out byte* bl
         {
             ArgumentNullException.ThrowIfNull(assembly);
 
+            if (assembly is RuntimeAssembly runtimeAssembly)
+            {
+                return runtimeAssembly.TryGetRawMetadata(out blob, out length);
+            }
+
             blob = null;
             length = 0;
             return false;

src/mono/System.Private.CoreLib/src/System/Reflection/RuntimeAssembly.cs

@@ -474,6 +474,12 @@ internal static RuntimeAssembly InternalLoad(AssemblyName assemblyRef, ref Stack
             return res;
         }
 
+        internal unsafe bool TryGetRawMetadata(out byte* blob, out int length)
+        {
+            var this_assembly = this;
+            return InternalTryGetRawMetadata(new QCallAssembly(ref this_assembly), out blob, out length);
+        }
+
         [MethodImplAttribute(MethodImplOptions.InternalCall)]
         private static extern bool GetManifestResourceInfoInternal(QCallAssembly assembly, string name, ManifestResourceInfo info);
 
@@ -489,6 +495,9 @@ internal static RuntimeAssembly InternalLoad(AssemblyName assemblyRef, ref Stack
         [MethodImplAttribute(MethodImplOptions.InternalCall)]
         private static extern IntPtr InternalGetReferencedAssemblies(Assembly assembly);
 
+        [MethodImplAttribute(MethodImplOptions.InternalCall)]
+        private static extern unsafe bool InternalTryGetRawMetadata(QCallAssembly assembly, out byte* blob, out int length);
+
         internal string? GetSimpleName()
         {
             // TODO: Make this cheaper and faster

src/mono/mono/metadata/icall-def.h

@@ -364,6 +364,7 @@ HANDLES(RASSEM_5, "GetManifestResourceNames", ves_icall_System_Reflection_Runtim
 HANDLES(RASSEM_6, "GetModulesInternal", ves_icall_System_Reflection_RuntimeAssembly_GetModulesInternal, void, 2, (MonoQCallAssemblyHandle, MonoObjectHandleOnStack))
 HANDLES(RASSEM_6b, "GetTopLevelForwardedTypes", ves_icall_System_Reflection_RuntimeAssembly_GetTopLevelForwardedTypes, void, 2, (MonoQCallAssemblyHandle, MonoObjectHandleOnStack))
 HANDLES(RASSEM_7, "InternalGetReferencedAssemblies", ves_icall_System_Reflection_Assembly_InternalGetReferencedAssemblies, GPtrArray_ptr, 1, (MonoReflectionAssembly))
+HANDLES(RASSEM_8, "InternalTryGetRawMetadata", ves_icall_System_Reflection_RuntimeAssembly_InternalTryGetRawMetadata, MonoBoolean, 3, (MonoQCallAssemblyHandle, gpointer_ref, gint32_ref))
 
 ICALL_TYPE(MCMETH, "System.Reflection.RuntimeConstructorInfo", MCMETH_1)
 HANDLES(MCMETH_1, "GetGenericMethodDefinition_impl", ves_icall_RuntimeMethodInfo_GetGenericMethodDefinition, MonoReflectionMethod, 1, (MonoReflectionMethod))

src/mono/mono/metadata/icall.c

@@ -4747,6 +4747,18 @@ ves_icall_System_Reflection_Assembly_InternalGetReferencedAssemblies (MonoReflec
 	return result;
 }
 
+MonoBoolean
+ves_icall_System_Reflection_RuntimeAssembly_InternalTryGetRawMetadata (MonoQCallAssemblyHandle assembly_h, gpointer_ref blob, gint32_ref length, MonoError *error)
+{
+	MonoAssembly *assembly = assembly_h.assembly;
+	MonoImage *image = assembly->image;
+
+	*blob = image->raw_metadata;
+	*((guint32*)length) = image->raw_metadata_len;
+
+	return *blob != NULL;
+}
+
 /* move this in some file in mono/util/ */
 static char *
 g_concat_dir_and_file (const char *dir, const char *file)

src/mono/mono/metadata/image.c

@@ -468,6 +468,7 @@ load_metadata_ptrs (MonoImage *image, MonoCLIImageInfo *iinfo)
 	if (offset + size > image->raw_data_len)
 		return FALSE;
 	image->raw_metadata = image->raw_data + offset;
+	image->raw_metadata_len = size;
 
 	/* 24.2.1: Metadata root starts here */
 	ptr = image->raw_metadata;

src/mono/mono/metadata/metadata-internals.h

@@ -362,6 +362,7 @@ struct _MonoImage {
 	MonoMemPool         *mempool; /*protected by the image lock*/
 
 	char                *raw_metadata;
+	guint32              raw_metadata_len;
 
 	MonoStreamHeader     heap_strings;
 	MonoStreamHeader     heap_us;