Do not look for StackTraceHiddenAttribute if there's none in the app

Author: MichalStrehovsky

src/coreclr/nativeaot/System.Private.StackTraceMetadata/src/Internal/StackTraceMetadata/StackTraceMetadata.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Reflection.Runtime.General;
+using System.Runtime.CompilerServices;
 
 using Internal.Metadata.NativeFormat;
 using Internal.NativeFormat;
@@ -41,6 +42,10 @@ internal static void Initialize()
             RuntimeAugments.InitializeStackTraceMetadataSupport(new StackTraceMetadataCallbacksImpl());
         }
 
+        [Intrinsic]
+        [AnalysisCharacteristic]
+        internal static extern bool StackTraceHiddenMetadataPresent();
+
         /// <summary>
         /// Locate the containing module for a method and try to resolve its name based on start address.
         /// </summary>
@@ -75,21 +80,24 @@ public static unsafe string GetMethodNameFromStartAddressIfAvailable(IntPtr meth
                 out TypeDefinitionHandle typeHandle,
                 out MethodHandle methodHandle))
             {
-                foreach (CustomAttributeHandle cah in reader.GetTypeDefinition(typeHandle).CustomAttributes)
+                if (StackTraceHiddenMetadataPresent())
                 {
-                    if (cah.IsCustomAttributeOfType(reader, ["System", "Diagnostics"], "StackTraceHiddenAttribute"))
+                    foreach (CustomAttributeHandle cah in reader.GetTypeDefinition(typeHandle).CustomAttributes)
                     {
-                        isStackTraceHidden = true;
-                        break;
+                        if (cah.IsCustomAttributeOfType(reader, ["System", "Diagnostics"], "StackTraceHiddenAttribute"))
+                        {
+                            isStackTraceHidden = true;
+                            break;
+                        }
                     }
-                }
 
-                foreach (CustomAttributeHandle cah in reader.GetMethod(methodHandle).CustomAttributes)
-                {
-                    if (cah.IsCustomAttributeOfType(reader, ["System", "Diagnostics"], "StackTraceHiddenAttribute"))
+                    foreach (CustomAttributeHandle cah in reader.GetMethod(methodHandle).CustomAttributes)
                     {
-                        isStackTraceHidden = true;
-                        break;
+                        if (cah.IsCustomAttributeOfType(reader, ["System", "Diagnostics"], "StackTraceHiddenAttribute"))
+                        {
+                            isStackTraceHidden = true;
+                            break;
+                        }
                     }
                 }
 

src/coreclr/nativeaot/System.Private.StackTraceMetadata/src/System.Private.StackTraceMetadata.csproj

@@ -23,5 +23,7 @@
     <Compile Include="$(CompilerCommonPath)\Internal\Runtime\StackTraceData.cs">
       <Link>Internal\Runtime\StackTraceData.cs</Link>
     </Compile>
+    <Compile Include="..\..\System.Private.CoreLib\src\System\Runtime\CompilerServices\AnalysisCharacteristicAttribute.cs" />
+    <Compile Include="..\..\Runtime.Base\src\System\Runtime\CompilerServices\IntrinsicAttribute.cs" />
   </ItemGroup>
 </Project>

src/coreclr/tools/aot/ILCompiler.Compiler/Compiler/DependencyAnalysis/MethodMetadataNode.cs

@@ -40,7 +40,9 @@ public MethodMetadataNode(MethodDesc method, bool isMinimal)
         public override IEnumerable<DependencyListEntry> GetStaticDependencies(NodeFactory factory)
         {
             DependencyList dependencies = new DependencyList();
-            dependencies.Add(factory.TypeMetadata((MetadataType)_method.OwningType), "Owning type metadata");
+
+            var owningType = (MetadataType)_method.OwningType;
+            dependencies.Add(factory.TypeMetadata(owningType), "Owning type metadata");
 
             if (!_isMinimal)
             {
@@ -77,6 +79,12 @@ public override IEnumerable<DependencyListEntry> GetStaticDependencies(NodeFacto
                 {
                     GenericArgumentDataFlow.ProcessGenericArgumentDataFlow(ref dependencies, factory, new MessageOrigin(_method), parameterType, _method);
                 }
+
+                if (_method.HasCustomAttribute("System.Diagnostics", "StackTraceHiddenAttribute")
+                    || owningType.HasCustomAttribute("System.Diagnostics", "StackTraceHiddenAttribute"))
+                {
+                    dependencies.Add(factory.AnalysisCharacteristic("StackTraceHiddenMetadataPresent"), "Method is StackTraceHidden");
+                }
             }
 
             return dependencies;

src/tests/nativeaot/SmokeTests/AttributeTrimming/AttributeTrimming.cs

@@ -0,0 +1,34 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
+
+[Type]
+class Program
+{
+    [Method]
+    static int Main()
+    {
+        // Sanity check: we don't currently expect attributes on types to be optimized away
+        if (GetTypeSecretly(nameof(TypeAttribute)) == null)
+            throw new Exception("Type");
+
+        // Main should be reflection visible
+        if (MethodBase.GetCurrentMethod().Name != nameof(Main))
+            throw new Exception("Name");
+
+        // But we should have optimized out the attributes on it
+        if (GetTypeSecretly(nameof(MethodAttribute)) != null)
+            throw new Exception("Method");
+
+        return 100;
+    }
+
+    [UnconditionalSuppressMessage("Trimming", "IL2057", Justification = "That's the point")]
+    static Type GetTypeSecretly(string name) => Type.GetType(name);
+}
+
+class MethodAttribute : Attribute;
+class TypeAttribute : Attribute;

src/tests/nativeaot/SmokeTests/AttributeTrimming/AttributeTrimming.csproj

@@ -0,0 +1,13 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <CLRTestPriority>0</CLRTestPriority>
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    <RequiresProcessIsolation>true</RequiresProcessIsolation>
+    <ReferenceXUnitWrapperGenerator>false</ReferenceXUnitWrapperGenerator>
+    <Optimize>true</Optimize>
+  </PropertyGroup>
+  <ItemGroup>
+    <Compile Include="AttributeTrimming.cs" />
+  </ItemGroup>
+</Project>