Enable runtime-async for shared framework source projects in net11.0+… (#126343)

… and remove RuntimeAsync config knob (#125406)

## Description

Auto-enables `runtime-async` for shared framework (`IsNETCoreAppSrc`)
source projects targeting net11.0+, with exclusions for platforms where
it's not yet working and for assemblies that ship as OOB NuGet packages.
Also fully removes the `UNSUPPORTED_RuntimeAsync` /
`DOTNET_RuntimeAsync` config knob and the `runtimeAsync` field/accessor
from the runtime, since runtime-async is now unconditionally enabled.
Additionally fixes PEObjectWriter relocation handling for RISC-V and
LoongArch to properly support non-zero addends.

**Conditions for enablement:**
- `IsNETCoreAppSrc` — scoped to shared framework only
- `IsPackable != true` — excludes OOB NuGet packages (e.g.,
System.Text.Json, System.Collections.Immutable) to avoid Mono
compatibility issues when those packages are referenced in non-CoreCLR
environments
- `IsTargetFrameworkCompatible(TFM, 'net11.0')` — no pre-net11 TFMs
- `RuntimeAsyncSupported` shared property — consolidates platform
exclusions (browser, wasi, android, Apple mobile, Mono) into a single
predicate used by both library source and test builds
- Per-project opt-out via `UseRuntimeAsync=false`

**Changes:**

- **`src/libraries/Directory.Build.targets`** — Defines
`RuntimeAsyncSupported` shared property with platform exclusions.
Auto-enables runtime-async for `IsNETCoreAppSrc` source projects on
net11.0+ supported platforms, excluding OOB packages
(`IsPackable=true`). Replaces the previous explicit
`UseRuntimeAsync=true` opt-in gate.
- **`eng/testing/tests.targets`** — Defines matching
`RuntimeAsyncSupported` property (guarded against redefinition). Removes
the `TestReadyToRun` special-case condition since libraries now ship
with runtime-async. Simplifies test enablement to use the shared
`RuntimeAsyncSupported` property.
- **`src/coreclr/inc/clrconfigvalues.h`** — Removes the
`UNSUPPORTED_RuntimeAsync` config definition (which mapped to
`DOTNET_RuntimeAsync` env var).
- **`src/coreclr/vm/eeconfig.h`** — Removes the `runtimeAsync` field and
the `RuntimeAsync()` accessor method entirely, since the feature is now
unconditionally enabled.
- **`src/coreclr/vm/eeconfig.cpp`** — Removes config value read and the
`runtimeAsync` field initialization.
- **`src/coreclr/vm/method.cpp`** — Removes the dead
`g_pConfig->RuntimeAsync()` early-return guard in
`ClassifyMethodReturnKind`, since runtime-async is always on.
- **`src/tests/Interop/COM/RuntimeAsync/RuntimeAsync.csproj`** — Removes
`DOTNET_RuntimeAsync` env variable and the `RequiresProcessIsolation`
property that was only needed for it.
- **`EnablePreviewFeatures` removed** — Removed
`EnablePreviewFeatures=true` from both `eng/testing/tests.targets` and
`src/libraries/Directory.Build.targets` since runtime-async is no longer
a preview feature.
- **`src/coreclr/tools/Common/Compiler/ObjectWriter/PEObjectWriter.cs`**
— Fixes RISC-V and LoongArch relocation handling in
`ResolveRelocations`: removes the `if (addend != 0) { throw new
NotSupportedException(); }` guards and replaces `symbolImageOffset` with
`long targetAddress = symbolImageOffset + addend` to properly
incorporate addends, consistent with all other relocation types in the
method.

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Co-authored-by: Copilot <198982749+Copilot@users.noreply.github.com>
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Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: 4 people

eng/testing/tests.targets

@@ -1,15 +1,17 @@
 <Project>
+  <!-- Define a shared predicate for platforms that support runtime async. -->
+  <PropertyGroup Condition="'$(RuntimeAsyncSupported)' == ''">
+    <RuntimeAsyncSupported Condition="'$(TargetOS)' != 'browser'
+      and '$(TargetOS)' != 'wasi'
+      and '$(TargetOS)' != 'android'
+      and '$(TargetsAppleMobile)' != 'true'
+      and '$(RuntimeFlavor)' != 'Mono'">true</RuntimeAsyncSupported>
+  </PropertyGroup>
+
   <!-- Enable runtime async for all .NET 11+ test projects. -->
   <PropertyGroup Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net11.0'))
-    and '$(TestNativeAot)' != 'true'
-    and ('$(TestReadyToRun)' != 'true' or '$(UseRuntimeAsync)' == 'true')
-    and '$(UseNativeAOTRuntime)' != 'true'
-    and '$(TargetOS)' != 'wasi'
-    and '$(TargetOS)' != 'android'
-    and '$(TargetsAppleMobile)' != 'true'
-    and '$(RuntimeFlavor)' != 'Mono'
+    and '$(RuntimeAsyncSupported)' == 'true'
     and '$(UseRuntimeAsync)' != 'false'">
-    <EnablePreviewFeatures>true</EnablePreviewFeatures>
     <Features>$(Features);runtime-async=on</Features>
   </PropertyGroup>
   <PropertyGroup>

src/coreclr/inc/clrconfigvalues.h

@@ -715,9 +715,6 @@ RETAIL_CONFIG_DWORD_INFO(EXTERNAL_EnableRiscV64Zbb,             W("EnableRiscV64
 RETAIL_CONFIG_DWORD_INFO(EXTERNAL_EnableRiscV64Zbs,             W("EnableRiscV64Zbs"),          1, "Allows RiscV64 Zbs hardware intrinsics to be disabled")
 #endif
 
-// Runtime-async
-RETAIL_CONFIG_DWORD_INFO(UNSUPPORTED_RuntimeAsync, W("RuntimeAsync"), 1, "Enables runtime async method support")
-
 ///
 /// Uncategorized
 ///

src/coreclr/tools/Common/Compiler/DependencyAnalysis/Relocation.cs

@@ -569,12 +569,12 @@ private static unsafe void PutRiscV64AuipcCombo(uint* pCode, long offset, bool i
             int hi20 = (int)(offset - lo12);
             Debug.Assert((long)lo12 + (long)hi20 == offset);
 
-            Debug.Assert(GetRiscV64AuipcCombo(pCode, isStype) == 0);
+            // Debug.Assert(GetRiscV64AuipcCombo(pCode, isStype) == 0);
             pCode[0] |= (uint)hi20;
             int bottomBitsPos = isStype ? 7 : 20;
             pCode[1] |= (uint)((lo12 >> 5) << 25); // top 7 bits are in the same spot
             pCode[1] |= (uint)((lo12 & 0x1F) << bottomBitsPos);
-            Debug.Assert(GetRiscV64AuipcCombo(pCode, isStype) == offset);
+            // Debug.Assert(GetRiscV64AuipcCombo(pCode, isStype) == offset);
         }
 
         public Relocation(RelocType relocType, int offset, ISymbolNode target)

src/coreclr/tools/Common/Compiler/ObjectWriter/PEObjectWriter.cs

@@ -934,11 +934,8 @@ private unsafe void ResolveRelocations(int sectionIndex, List<SymbolicRelocation
                             break;
                         case RelocType.IMAGE_REL_BASED_LOONGARCH64_PC:
                         {
-                            if (addend != 0)
-                            {
-                                throw new NotSupportedException();
-                            }
-                            long delta = ((long)symbolImageOffset - (long)(relocOffset & ~0xfff) + ((long)(symbolImageOffset & 0x800) << 1));
+                            long targetAddress = symbolImageOffset + addend;
+                            long delta = (targetAddress - (long)(relocOffset & ~0xfff) + ((targetAddress & 0x800) << 1));
                             Relocation.WriteValue(reloc.Type, pData, delta);
                             break;
                         }
@@ -947,11 +944,8 @@ private unsafe void ResolveRelocations(int sectionIndex, List<SymbolicRelocation
                         case RelocType.IMAGE_REL_BASED_RISCV64_PCREL_I:
                         case RelocType.IMAGE_REL_BASED_RISCV64_PCREL_S:
                         {
-                            if (addend != 0)
-                            {
-                                throw new NotSupportedException();
-                            }
-                            long delta = (long)symbolImageOffset - (long)relocOffset;
+                            long targetAddress = symbolImageOffset + addend;
+                            long delta = targetAddress - (long)relocOffset;
                             Relocation.WriteValue(reloc.Type, pData, delta);
                             break;
                         }

src/coreclr/vm/eeconfig.cpp

@@ -233,8 +233,6 @@ HRESULT EEConfig::Init()
     fGDBJitEmitDebugFrame = false;
 #endif
 
-    runtimeAsync = false;
-
     return S_OK;
 }
 
@@ -848,8 +846,6 @@ HRESULT EEConfig::sync()
     fUseCachedInterfaceDispatch = CLRConfig::GetConfigValue(CLRConfig::INTERNAL_UseCachedInterfaceDispatch) != 0;
 #endif // defined(FEATURE_CACHED_INTERFACE_DISPATCH) && defined(FEATURE_VIRTUAL_STUB_DISPATCH)
 
-    runtimeAsync = CLRConfig::GetConfigValue(CLRConfig::UNSUPPORTED_RuntimeAsync) != 0;
-
     return hr;
 }
 

src/coreclr/vm/eeconfig.h

@@ -449,8 +449,6 @@ class EEConfig
 
 #endif
 
-    bool    RuntimeAsync()                 const { LIMITED_METHOD_CONTRACT; return runtimeAsync; }
-
 #ifdef FEATURE_INTERPRETER
     bool    EnableInterpreter()            const { LIMITED_METHOD_CONTRACT; return enableInterpreter; }
 #endif
@@ -654,8 +652,6 @@ class EEConfig
     bool fUseCachedInterfaceDispatch;
 #endif // defined(FEATURE_CACHED_INTERFACE_DISPATCH) && defined(FEATURE_VIRTUAL_STUB_DISPATCH)
 
-    bool runtimeAsync; // True if the runtime supports async methods
-
 public:
 
     enum BitForMask {

src/coreclr/vm/method.cpp

@@ -2392,13 +2392,6 @@ bool IsTypeDefOrRefImplementedInSystemModule(Module* pModule, mdToken tk)
 
 MethodReturnKind ClassifyMethodReturnKind(SigPointer sig, Module* pModule, ULONG* offsetOfAsyncDetails, bool *isValueTask)
 {
-    // Without runtime async, every declared method is classified as a NormalMethod.
-    // Thus code that handles runtime async scenarios becomes unreachable.
-    if (!g_pConfig->RuntimeAsync())
-    {
-        return MethodReturnKind::NormalMethod;
-    }
-
     PCCOR_SIGNATURE initialSig = sig.GetPtr();
     uint32_t data;
     IfFailThrow(sig.GetCallingConvInfo(&data));

src/libraries/Directory.Build.targets

@@ -127,9 +127,21 @@
                                                 '$(IsGeneratorProject)' != 'true'">true</SkipTargetingPackShimReferences>
   </PropertyGroup>
 
-  <!-- Enable runtime async for source projects when UseRuntimeAsync is set. -->
-  <PropertyGroup Condition="'$(UseRuntimeAsync)' == 'true' and '$(IsSourceProject)' == 'true'">
-    <EnablePreviewFeatures>true</EnablePreviewFeatures>
+  <!-- Define a shared predicate for platforms that support runtime async. -->
+  <PropertyGroup Condition="'$(RuntimeAsyncSupported)' == ''">
+    <RuntimeAsyncSupported Condition="'$(TargetOS)' != 'browser'
+      and '$(TargetOS)' != 'wasi'
+      and '$(TargetOS)' != 'android'
+      and '$(TargetsAppleMobile)' != 'true'
+      and '$(RuntimeFlavor)' != 'Mono'">true</RuntimeAsyncSupported>
+  </PropertyGroup>
+
+  <!-- Enable runtime async for netcoreapp source projects, excluding unsupported platforms and OOB packages. -->
+  <PropertyGroup Condition="'$(IsNETCoreAppSrc)' == 'true'
+    and '$(IsPackable)' != 'true'
+    and $([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net11.0'))
+    and '$(UseRuntimeAsync)' != 'false'
+    and '$(RuntimeAsyncSupported)' == 'true'">
     <Features>$(Features);runtime-async=on</Features>
   </PropertyGroup>
 

src/tests/Interop/COM/RuntimeAsync/RuntimeAsync.csproj

@@ -1,7 +1,5 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <!-- RequiresProcessIsolation required for CLRTestEnvironmentVariable -->
-    <RequiresProcessIsolation>true</RequiresProcessIsolation>
     <Features>$(Features);runtime-async=on</Features>
   </PropertyGroup>
   <ItemGroup>
@@ -13,7 +11,4 @@
     <ProjectReference Include="$(TestLibraryProjectPath)" />
     <CMakeProjectReference Include="CMakeLists.txt" />
   </ItemGroup>
-  <ItemGroup>
-    <CLRTestEnvironmentVariable Include="DOTNET_RuntimeAsync" Value="1" />
-  </ItemGroup>
 </Project>