Implement load_assembly_bytes delegate for hosting API

src/installer/tests/Assets/TestProjects/ComponentWithNoDependencies/Component.cs

@@ -19,6 +19,7 @@ static Component()
         {
             Assembly asm = Assembly.GetExecutingAssembly();
             Console.WriteLine($"{asm.GetName().Name}: AssemblyLoadContext = {AssemblyLoadContext.GetLoadContext(asm)}");
+            Console.WriteLine($"{asm.GetName().Name}: Location = '{asm.Location}'");
         }
 
         private static void PrintComponentCallLog(string name, IntPtr arg, int size)

src/installer/tests/HostActivation.Tests/NativeHosting/FunctionPointerResultExtensions.cs

@@ -42,5 +42,10 @@ public static FluentAssertions.AndConstraint<CommandResultAssertions> ExecuteInD
         {
             return assertion.HaveStdOutContaining($"{assemblyName}: AssemblyLoadContext = \"Default\" System.Runtime.Loader.DefaultAssemblyLoadContext");
         }
+
+        public static FluentAssertions.AndConstraint<CommandResultAssertions> ExecuteWithLocation(this CommandResultAssertions assertion, string assemblyName, string location)
+        {
+            return assertion.HaveStdOutContaining($"{assemblyName}: Location = '{location}'");
+        }
     }
 }

src/installer/tests/HostActivation.Tests/NativeHosting/LoadAssembly.cs

@@ -11,89 +11,128 @@
 
 namespace Microsoft.DotNet.CoreSetup.Test.HostActivation.NativeHosting
 {
-    public partial class LoadAssembly : IClassFixture<LoadAssembly.SharedTestState>
+    public class LoadAssembly : IClassFixture<LoadAssembly.SharedTestState>
     {
         private const string AppLoadAssemblyArg = "app_load_assembly";
         private const string ComponentLoadAssemblyArg = "component_load_assembly";
 
+        private const string AppLoadAssemblyBytesArg = "app_load_assembly_bytes";
+        private const string ComponentLoadAssemblyBytesArg = "component_load_assembly_bytes";
+
         private readonly SharedTestState sharedState;
 
         public LoadAssembly(SharedTestState sharedTestState)
         {
             sharedState = sharedTestState;
         }
 
-        [Fact]
-        public void ApplicationContext()
+        private void ApplicationContext(bool loadAssemblyBytes, bool loadSymbolBytes)
         {
-            var appProject = sharedState.Application;
-            var componentProject = sharedState.ComponentWithNoDependenciesFixture.TestProject;
-            string[] args =
+            var app = sharedState.Application;
+            var component = sharedState.Component;
+            IEnumerable<string> args = new[]
             {
-                AppLoadAssemblyArg,
+                loadAssemblyBytes ? AppLoadAssemblyBytesArg : AppLoadAssemblyArg,
                 sharedState.HostFxrPath,
-                appProject.AppDll,
-                componentProject.AppDll,
-                sharedState.ComponentTypeName,
-                sharedState.ComponentEntryPoint1,
-            };
+                app.AppDll
+            }.Concat(sharedState.GetComponentLoadArgs(loadAssemblyBytes, loadSymbolBytes));
+
             CommandResult result = sharedState.CreateNativeHostCommand(args, sharedState.DotNetRoot)
                 .Execute();
 
             result.Should().Pass()
-                .And.InitializeContextForApp(appProject.AppDll)
+                .And.InitializeContextForApp(app.AppDll)
                 .And.ExecuteSelfContained(selfContained: false)
-                .And.ExecuteInDefaultContext(componentProject.AssemblyName)
+                .And.ExecuteInDefaultContext(component.AssemblyName)
+                .And.ExecuteWithLocation(component.AssemblyName, loadAssemblyBytes ? string.Empty : component.AppDll)
                 .And.ExecuteFunctionPointer(sharedState.ComponentEntryPoint1, 1, 1);
         }
 
         [Fact]
-        public void ComponentContext()
+        public void ApplicationContext_FilePath()
+        {
+            ApplicationContext(loadAssemblyBytes: false, loadSymbolBytes: false);
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void ApplicationContext_Bytes(bool loadSymbolBytes)
+        {
+            ApplicationContext(loadAssemblyBytes: true, loadSymbolBytes);
+        }
+
+        private void ComponentContext(bool loadAssemblyBytes, bool loadSymbolBytes)
         {
-            var appProject = sharedState.Application;
-            var componentProject = sharedState.ComponentWithNoDependenciesFixture.TestProject;
-            string[] args =
+            var app = sharedState.Application;
+            var component = sharedState.Component;
+            IEnumerable<string> args = new[]
             {
-                ComponentLoadAssemblyArg,
+                loadAssemblyBytes ? ComponentLoadAssemblyBytesArg : ComponentLoadAssemblyArg,
                 sharedState.HostFxrPath,
-                componentProject.RuntimeConfigJson,
-                componentProject.AppDll,
-                sharedState.ComponentTypeName,
-                sharedState.ComponentEntryPoint1,
-            };
+                component.RuntimeConfigJson
+            }.Concat(sharedState.GetComponentLoadArgs(loadAssemblyBytes, loadSymbolBytes));
+
             CommandResult result = sharedState.CreateNativeHostCommand(args, sharedState.DotNetRoot)
                 .Execute();
 
             result.Should().Pass()
-                .And.InitializeContextForConfig(componentProject.RuntimeConfigJson)
-                .And.ExecuteInDefaultContext(componentProject.AssemblyName)
+                .And.InitializeContextForConfig(component.RuntimeConfigJson)
+                .And.ExecuteInDefaultContext(component.AssemblyName)
+                .And.ExecuteWithLocation(component.AssemblyName, loadAssemblyBytes ? string.Empty : component.AppDll)
                 .And.ExecuteFunctionPointer(sharedState.ComponentEntryPoint1, 1, 1);
         }
 
         [Fact]
-        public void SelfContainedApplicationContext()
+        public void ComponentContext_FilePath()
+        {
+            ComponentContext(loadAssemblyBytes: false, loadSymbolBytes: false);
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void ComponentContext_Bytes(bool loadSymbolBytes)
+        {
+            ComponentContext(loadAssemblyBytes: true, loadSymbolBytes);
+        }
+
+        private void SelfContainedApplicationContext(bool loadAssemblyBytes, bool loadSymbolBytes)
         {
-            var appProject = sharedState.SelfContainedApplication;
-            var componentProject = sharedState.ComponentWithNoDependenciesFixture.TestProject;
-            string[] args =
+            var app = sharedState.SelfContainedApplication;
+            var component = sharedState.Component;
+            IEnumerable<string> args = new[]
             {
-                AppLoadAssemblyArg,
-                appProject.HostFxrDll,
-                appProject.AppDll,
-                componentProject.AppDll,
-                sharedState.ComponentTypeName,
-                sharedState.ComponentEntryPoint1
-            };
+                loadAssemblyBytes ? AppLoadAssemblyBytesArg : AppLoadAssemblyArg,
+                app.HostFxrDll,
+                app.AppDll
+            }.Concat(sharedState.GetComponentLoadArgs(loadAssemblyBytes, loadSymbolBytes));
+
             CommandResult result = sharedState.CreateNativeHostCommand(args, sharedState.DotNetRoot)
                 .Execute();
 
             result.Should().Pass()
-                .And.InitializeContextForApp(appProject.AppDll)
+                .And.InitializeContextForApp(app.AppDll)
                 .And.ExecuteSelfContained(selfContained: true)
-                .And.ExecuteInDefaultContext(componentProject.AssemblyName)
+                .And.ExecuteInDefaultContext(component.AssemblyName)
+                .And.ExecuteWithLocation(component.AssemblyName, loadAssemblyBytes ? string.Empty : component.AppDll)
                 .And.ExecuteFunctionPointer(sharedState.ComponentEntryPoint1, 1, 1);
         }
 
+        [Fact]
+        public void SelfContainedApplicationContext_FilePath()
+        {
+            SelfContainedApplicationContext(loadAssemblyBytes: false, loadSymbolBytes: false);
+        }
+
+        [Theory]
+        [InlineData(true)]
+        [InlineData(false)]
+        public void SelfContainedApplicationContext_Bytes(bool loadSymbolBytes)
+        {
+            SelfContainedApplicationContext(loadAssemblyBytes: true, loadSymbolBytes);
+        }
+
         public class SharedTestState : SharedTestStateBase
         {
             public string HostFxrPath { get; }
@@ -103,10 +142,10 @@ public class SharedTestState : SharedTestStateBase
             public TestApp SelfContainedApplication { get; }
 
             public TestProjectFixture ComponentWithNoDependenciesFixture { get; }
+            public TestApp Component => ComponentWithNoDependenciesFixture.TestProject.BuiltApp;
 
             public string ComponentTypeName { get; }
             public string ComponentEntryPoint1 => "ComponentEntryPoint1";
-            public string UnmanagedFunctionPointerEntryPoint1 => "UnmanagedFunctionPointerEntryPoint1";
 
             public SharedTestState()
             {
@@ -127,6 +166,17 @@ public SharedTestState()
                 ComponentTypeName = $"Component.Component, {ComponentWithNoDependenciesFixture.TestProject.AssemblyName}";
             }
 
+            internal IEnumerable<string> GetComponentLoadArgs(bool loadAssemblyBytes, bool loadSymbolBytes)
+            {
+                List<string> args = new List<string>() { Component.AppDll };
+                if (loadAssemblyBytes)
+                    args.Add(loadSymbolBytes ? $"{Path.GetFileNameWithoutExtension(Component.AppDll)}.pdb" : "nullptr");
+
+                args.Add(ComponentTypeName);
+                args.Add(ComponentEntryPoint1);
+                return args;
+            }
+
             protected override void Dispose(bool disposing)
             {
                 if (Application != null)

src/libraries/System.Private.CoreLib/src/ILLink/ILLink.Descriptors.LibraryBuild.xml

@@ -31,6 +31,7 @@
     <type fullname="Internal.Runtime.InteropServices.ComponentActivator">
       <!-- Used by hostpolicy.cpp -->
       <method name="LoadAssembly" />
+      <method name="LoadAssemblyBytes" />
       <method name="LoadAssemblyAndGetFunctionPointer" />
       <method name="GetFunctionPointer" />
     </type>

src/libraries/System.Private.CoreLib/src/ILLink/ILLink.Descriptors.Shared.xml

@@ -16,6 +16,7 @@
     -->
     <type fullname="Internal.Runtime.InteropServices.ComponentActivator">
       <method name="LoadAssembly" />
+      <method name="LoadAssemblyBytes" />
       <method name="LoadAssemblyAndGetFunctionPointer" />
     </type>
   </assembly>

src/libraries/System.Private.CoreLib/src/Internal/Runtime/InteropServices/ComponentActivator.cs

@@ -160,6 +160,56 @@ private static void LoadAssemblyImpl(string assemblyPath)
             }
         }
 
+        /// <summary>
+        /// Native hosting entry point for loading an assembly from a byte array
+        /// </summary>
+        /// <param name="assembly">Bytes of the assembly to load</param>
+        /// <param name="assemblyByteLength">Byte length of the assembly to load</param>
+        /// <param name="symbols">Optional. Bytes of the symbols for the assembly</param>
+        /// <param name="symbolsByteLength">Optional. Byte length of the symbols for the assembly</param>
+        /// <param name="loadContext">Extensibility parameter (currently unused)</param>
+        /// <param name="reserved">Extensibility parameter (currently unused)</param>
+        [RequiresDynamicCode(NativeAOTIncompatibleWarningMessage)]
+        [UnsupportedOSPlatform("android")]
+        [UnsupportedOSPlatform("browser")]
+        [UnsupportedOSPlatform("ios")]
+        [UnsupportedOSPlatform("maccatalyst")]
+        [UnsupportedOSPlatform("tvos")]
+        [UnmanagedCallersOnly]
+        public static unsafe int LoadAssemblyBytes(byte* assembly, nint assemblyByteLength, byte* symbols, nint symbolsByteLength, IntPtr loadContext, IntPtr reserved)
+        {
+            if (!IsSupported)
+                return HostFeatureDisabled;
+
+            try
+            {
+                ArgumentNullException.ThrowIfNull(assembly);
+                ArgumentOutOfRangeException.ThrowIfNegativeOrZero(assemblyByteLength);
+                ArgumentOutOfRangeException.ThrowIfGreaterThan(assemblyByteLength, int.MaxValue);
+                ArgumentOutOfRangeException.ThrowIfNotEqual(loadContext, IntPtr.Zero);
+                ArgumentOutOfRangeException.ThrowIfNotEqual(reserved, IntPtr.Zero);
+
+                ReadOnlySpan<byte> assemblySpan = new ReadOnlySpan<byte>(assembly, (int)assemblyByteLength);
+                ReadOnlySpan<byte> symbolsSpan = default;
+                if (symbols != null && symbolsByteLength > 0)
+                {
+                    symbolsSpan = new ReadOnlySpan<byte>(symbols, (int)symbolsByteLength);
+                }
+
+                LoadAssemblyBytesLocal(assemblySpan, symbolsSpan);
+            }
+            catch (Exception e)
+            {
+                return e.HResult;
+            }
+
+            return 0;
+
+            [UnconditionalSuppressMessage("ReflectionAnalysis", "IL2026:RequiresUnreferencedCode",
+                Justification = "The same feature switch applies to GetFunctionPointer and this function. We rely on the warning from GetFunctionPointer.")]
+            static void LoadAssemblyBytesLocal(ReadOnlySpan<byte> assemblyBytes, ReadOnlySpan<byte> symbolsBytes) => AssemblyLoadContext.Default.InternalLoad(assemblyBytes, symbolsBytes);
+        }
+
         /// <summary>
         /// Native hosting entry point for creating a native delegate
         /// </summary>

src/native/corehost/coreclr_delegates.h

@@ -49,4 +49,12 @@ typedef int (CORECLR_DELEGATE_CALLTYPE *load_assembly_fn)(
     void         *load_context      /* Extensibility parameter (currently unused and must be 0) */,
     void         *reserved          /* Extensibility parameter (currently unused and must be 0) */);
 
+typedef int (CORECLR_DELEGATE_CALLTYPE *load_assembly_bytes_fn)(
+    const void *assembly_bytes      /* Bytes of the assembly to load */,
+    size_t     assembly_bytes_len   /* Byte length of the assembly to load */,
+    const void *symbols_bytes       /* Optional. Bytes of the symbols for the assembly */,
+    size_t     symbols_bytes_len    /* Optional. Byte length of the symbols for the assembly */,
+    void       *load_context        /* Extensibility parameter (currently unused and must be 0) */,
+    void       *reserved            /* Extensibility parameter (currently unused and must be 0) */);
+
 #endif // __CORECLR_DELEGATES_H__

src/native/corehost/corehost_context_contract.h

@@ -29,6 +29,7 @@ enum class coreclr_delegate_type
     load_assembly_and_get_function_pointer,
     get_function_pointer,
     load_assembly,
+    load_assembly_bytes,
 
     __last, // Sentinel value for determining the last known delegate type
 };

src/native/corehost/fxr/hostfxr.cpp

@@ -669,6 +669,8 @@ namespace
             return coreclr_delegate_type::get_function_pointer;
         case hostfxr_delegate_type::hdt_load_assembly:
             return coreclr_delegate_type::load_assembly;
+        case hostfxr_delegate_type::hdt_load_assembly_bytes:
+            return coreclr_delegate_type::load_assembly_bytes;
         }
         return coreclr_delegate_type::invalid;
     }

src/native/corehost/hostfxr.h

@@ -29,6 +29,7 @@ enum hostfxr_delegate_type
     hdt_load_assembly_and_get_function_pointer,
     hdt_get_function_pointer,
     hdt_load_assembly,
+    hdt_load_assembly_bytes,
 };
 
 typedef int32_t(HOSTFXR_CALLTYPE *hostfxr_main_fn)(const int argc, const char_t **argv);

src/native/corehost/hostpolicy/hostpolicy.cpp

@@ -543,6 +543,12 @@ namespace
                 "Internal.Runtime.InteropServices.ComponentActivator",
                 "LoadAssembly",
                 delegate);
+        case coreclr_delegate_type::load_assembly_bytes:
+            return coreclr->create_delegate(
+                "System.Private.CoreLib",
+                "Internal.Runtime.InteropServices.ComponentActivator",
+                "LoadAssemblyBytes",
+                delegate);
         default:
             return StatusCode::LibHostInvalidArgs;
         }