[clr-interp] Enhance InterpMode and CI testing (#120955)

- Enhance InterpMode flag to autoimply various other flags like
ReadyToRun=0 EnableHWIntrinsic=0 consistently, so that InterpMode can be
used on its own to control interpretation behavior
- The comments around InterpMode are now accurate as to what they imply
- Enhance CI to allow testing of various interpreter scenarios (The
existing model + InterModes 1, 2, and 3)

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: davidwrighton

eng/pipelines/common/templates/runtimes/run-test-job.yml

@@ -332,7 +332,23 @@ jobs:
           msbuildParallelism: '/maxcpucount:55'
 
         ${{ if in(parameters.testGroup, 'innerloop', 'outerloop') }}:
-          ${{ if eq(parameters.runtimeFlavor, 'mono') }}:
+          ${{ if and(eq(parameters.runInterpreter, 'true'),eq(variables['Build.Reason'], 'PullRequest')) }}:
+            scenarios:
+            - interpmode3_no_tiered_compilation
+            - interpmode2_no_tiered_compilation
+            - interpmode1_no_tiered_compilation
+            - no_tiered_compilation
+          ${{ elseif eq(parameters.runInterpreter, 'true') }}:
+            scenarios:
+            - interpmode3_no_tiered_compilation
+            - interpmode3
+            - interpmode2_no_tiered_compilation
+            - interpmode2
+            - normal
+            - no_tiered_compilation
+            - interpmode1_no_tiered_compilation
+            - interpmode1
+          ${{ elseif eq(parameters.runtimeFlavor, 'mono') }}:
             # tiered compilation isn't done on mono yet
             scenarios:
             - normal

src/coreclr/interpreter/eeinterp.cpp

@@ -70,12 +70,12 @@ CorJitResult CILInterp::compileMethod(ICorJitInfo*         compHnd,
                 break;
             }
 
-            // 2: use interpreter for everything except intrinsics. All intrinsics fallback to JIT. Implies DOTNET_ReadyToRun=0.
+            // 2: use interpreter for everything except intrinsics. All intrinsics fallback to JIT. Implies DOTNET_ReadyToRun=0
             case 2:
                 doInterpret = !(compHnd->getMethodAttribs(methodInfo->ftn) & CORINFO_FLG_INTRINSIC);
                 break;
 
-            // 3: use interpreter for everything, the full interpreter-only mode, no fallbacks to R2R or JIT whatsoever. Implies DOTNET_ReadyToRun=0, DOTNET_EnableHWIntrinsic=0
+            // 3: use interpreter for everything, the full interpreter-only mode, no fallbacks to R2R or JIT whatsoever. Implies DOTNET_ReadyToRun=0, DOTNET_EnableHWIntrinsic=0, DOTNET_MaxVectorTBitWidth=128, DOTNET_PreferredVectorBitWidth=128
             case 3:
                 doInterpret = true;
                 break;

src/coreclr/vm/codeman.cpp

@@ -1196,6 +1196,14 @@ void EEJitManager::SetCpuInfo()
     // Get the maximum bitwidth of Vector<T>, rounding down to the nearest multiple of 128-bits
     uint32_t maxVectorTBitWidth = (CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_MaxVectorTBitWidth) / 128) * 128;
 
+#if defined(FEATURE_INTERPRETER)
+    if (maxVectorTBitWidth != 128 && CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_InterpMode) == 3)
+    {
+        // Disable larger Vector<T> sizes when interpreter is enabled
+        maxVectorTBitWidth = 128;
+    }
+#endif
+
 #if defined(TARGET_X86) || defined(TARGET_AMD64)
     CPUCompileFlags.Set(InstructionSet_VectorT128);
 
@@ -1213,7 +1221,7 @@ void EEJitManager::SetCpuInfo()
 
     // x86-64-v2
 
-    if (CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_EnableHWIntrinsic))
+    if (g_pConfig->EnableHWIntrinsic())
     {
         CPUCompileFlags.Set(InstructionSet_X86Base);
     }
@@ -1324,7 +1332,7 @@ void EEJitManager::SetCpuInfo()
 #elif defined(TARGET_ARM64)
     CPUCompileFlags.Set(InstructionSet_VectorT128);
 
-    if (CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_EnableHWIntrinsic))
+    if (g_pConfig->EnableHWIntrinsic())
     {
         CPUCompileFlags.Set(InstructionSet_ArmBase);
         CPUCompileFlags.Set(InstructionSet_AdvSimd);
@@ -1408,7 +1416,7 @@ void EEJitManager::SetCpuInfo()
         g_arm64_atomics_present = true;
     }
 #elif defined(TARGET_RISCV64)
-    if (CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_EnableHWIntrinsic))
+    if (g_pConfig->EnableHWIntrinsic())
     {
         CPUCompileFlags.Set(InstructionSet_RiscV64Base);
     }
@@ -1509,6 +1517,14 @@ void EEJitManager::SetCpuInfo()
 
     uint32_t preferredVectorBitWidth = (CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_PreferredVectorBitWidth) / 128) * 128;
 
+#ifdef FEATURE_INTERPRETER
+    if (CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_InterpMode) == 3)
+    {
+        // Disable larger Vector<T> sizes when interpreter is enabled, and not compiling S.P.Corelib
+        preferredVectorBitWidth = 128;
+    }
+#endif
+
     if ((preferredVectorBitWidth == 0) && throttleVector512)
     {
         preferredVectorBitWidth = 256;

src/coreclr/vm/eeconfig.cpp

@@ -454,8 +454,45 @@ HRESULT EEConfig::sync()
 
     pReadyToRunExcludeList = NULL;
 
+#ifdef FEATURE_INTERPRETER
+#ifdef FEATURE_JIT
+    LPWSTR interpreterConfig;
+    IfFailThrow(CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_Interpreter, &interpreterConfig));
+    if (interpreterConfig == NULL)
+    {
+        if ((CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_InterpMode) != 0))
+        {
+            enableInterpreter = true;
+        }
+    }
+    else
+    {
+        enableInterpreter = true;
+    }
+#else
+    enableInterpreter = true;
+#endif // FEATURE_JIT
+#endif // FEATURE_INTERPRETER
+
+    enableHWIntrinsic = (CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_EnableHWIntrinsic) != 0);
+#ifdef FEATURE_INTERPRETER
+    if (CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_InterpMode) == 3)
+    {
+        // InterpMode 3 disables all hw intrinsics
+        enableHWIntrinsic = false;
+    }
+#endif // FEATURE_INTERPRETER
+
 #if defined(FEATURE_READYTORUN)
     fReadyToRun = CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_ReadyToRun);
+#if defined(FEATURE_INTERPRETER)
+    if (fReadyToRun && CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_InterpMode) >= 2)
+    {
+        // ReadyToRun and Interpreter modes 2 and 3 are mutually exclusive.
+        // If both are set, Interpreter wins.
+        fReadyToRun = false;
+    }
+#endif // defined(FEATURE_INTERPRETER)
 
     if (fReadyToRun)
     {

src/coreclr/vm/eeconfig.h

@@ -441,6 +441,11 @@ class EEConfig
 
     bool    RuntimeAsync()                 const { LIMITED_METHOD_CONTRACT; return runtimeAsync; }
 
+#ifdef FEATURE_INTERPRETER
+    bool    EnableInterpreter()            const { LIMITED_METHOD_CONTRACT; return enableInterpreter; }
+#endif
+    bool    EnableHWIntrinsic()            const { LIMITED_METHOD_CONTRACT; return enableHWIntrinsic; }
+
 private: //----------------------------------------------------------------
 
     bool fInited;                   // have we synced to the registry at least once?
@@ -612,6 +617,12 @@ class EEConfig
     bool fReadyToRun;
 #endif
 
+    bool enableHWIntrinsic;
+
+#ifdef FEATURE_INTERPRETER
+    bool enableInterpreter;
+#endif
+
 #if defined(FEATURE_ON_STACK_REPLACEMENT)
     DWORD dwOSR_HitLimit;
     DWORD dwOSR_CounterBump;

src/coreclr/vm/jithost.cpp

@@ -26,6 +26,11 @@ int JitHost::getIntConfigValue(const char* name, int defaultValue)
 {
     WRAPPER_NO_CONTRACT;
 
+    if (!strcmp(name, "EnableHWIntrinsic"))
+    {
+        return g_pConfig->EnableHWIntrinsic() ? 1 : 0;
+    }
+
     StackSString str;
     SString(SString::Utf8Literal, name).ConvertToUnicode(str);
 

src/coreclr/vm/jitinterface.cpp

@@ -13423,15 +13423,9 @@ PCODE UnsafeJitFunction(PrepareCodeConfig* config,
 
 #ifdef FEATURE_INTERPRETER
     InterpreterJitManager* interpreterMgr = ExecutionManager::GetInterpreterJitManager();
-    if (!interpreterMgr->IsInterpreterLoaded())
+    if (!interpreterMgr->IsInterpreterLoaded() && g_pConfig->EnableInterpreter())
     {
-        LPWSTR interpreterConfig;
-        IfFailThrow(CLRConfig::GetConfigValue(CLRConfig::EXTERNAL_Interpreter, &interpreterConfig));
         if (
-#ifdef FEATURE_JIT
-            // If both JIT and interpret are available, load the interpreter for testing purposes only if the config switch is set
-            (interpreterConfig != NULL) &&
-#endif
             !interpreterMgr->LoadInterpreter())
         {
             EEPOLICY_HANDLE_FATAL_ERROR_WITH_MESSAGE(COR_E_EXECUTIONENGINE, W("Failed to load interpreter"));

src/tests/Common/CLRTest.Execute.Bash.targets

@@ -84,6 +84,11 @@ fi
       <BashCLRTestEnvironmentCompatibilityCheck Condition="'$(InterpreterIncompatible)' == 'true'"><![CDATA[
 $(BashCLRTestEnvironmentCompatibilityCheck)
 if [ ! -z "$RunInterpreter" ]
+then
+  echo SKIPPING EXECUTION BECAUSE the test is incompatible with the interpreter
+  exit $(IncompatibleTestBashScriptExitCode)
+fi
+if [ ! -z "$DOTNET_InterpMode" ]
 then
   echo SKIPPING EXECUTION BECAUSE the test is incompatible with the interpreter
   exit $(IncompatibleTestBashScriptExitCode)
@@ -407,8 +412,9 @@ if [ ! -z ${RunCrossGen2+x} ]%3B then
 fi
 
 if [ ! -z "$RunInterpreter" ]; then
-# $(InputAssemblyName)
-  export DOTNET_Interpreter='$(AssemblyName)!*'
+  if [ -z "$DOTNET_InterpMode" ]; then
+    export DOTNET_Interpreter='$(AssemblyName)!*'
+  fi
 fi
 
 echo $LAUNCHER $ExePath %24(printf "'%s' " "${CLRTestExecutionArguments[@]}")

src/tests/Common/CLRTest.Execute.Batch.targets

@@ -80,6 +80,11 @@ IF NOT "%RunInterpreter%"=="" (
   ECHO SKIPPING EXECUTION BECAUSE the test is incompatible with the interpreter
   popd
   Exit /b 0
+)
+IF NOT "%DOTNET_InterpMode%"=="" (
+  ECHO SKIPPING EXECUTION BECAUSE the test is incompatible with the interpreter
+  popd
+  Exit /b 0
 )
       ]]></BatchCLRTestEnvironmentCompatibilityCheck>
       <BatchCLRTestEnvironmentCompatibilityCheck Condition="'$(TieringTestIncompatible)' == 'true'"><![CDATA[
@@ -345,7 +350,9 @@ if defined RunCrossGen2 (
 )
 
 if defined RunInterpreter (
-  SET "DOTNET_Interpreter=$(AssemblyName)^!*"
+  if "%DOTNET_InterpMode%"=="" (
+    SET "DOTNET_Interpreter=$(AssemblyName)^!*"
+  )
 )
 
 ECHO %LAUNCHER% %ExePath% %CLRTestExecutionArguments%

src/tests/Common/testenvironment.proj

@@ -13,6 +13,7 @@
   -->
   <PropertyGroup>
     <DOTNETVariables>
+      DOTNET_InterpMode;
       DOTNET_TieredCompilation;
       DOTNET_DbgEnableMiniDump;
       DOTNET_EnableCrashReport;
@@ -95,6 +96,12 @@
          while other scenarios use the default values of DOTNET_* variables defined in ItemDefinitionGroup above -->
     <TestEnvironment Include="normal" TieredCompilation="" />
     <TestEnvironment Include="jitminopts" JITMinOpts="1" />
+    <TestEnvironment Include="interpmode1" TieredCompilation="" InterpMode="1" />
+    <TestEnvironment Include="interpmode2" TieredCompilation="" InterpMode="2" />
+    <TestEnvironment Include="interpmode3" TieredCompilation="" InterpMode="3" />
+    <TestEnvironment Include="interpmode1_no_tiered_compilation" InterpMode="1" TieredCompilation="0"/>
+    <TestEnvironment Include="interpmode2_no_tiered_compilation" InterpMode="2" TieredCompilation="0"/>
+    <TestEnvironment Include="interpmode3_no_tiered_compilation" InterpMode="3" TieredCompilation="0"/>
     <TestEnvironment Include="no_tiered_compilation" TieredCompilation="0" />
     <TestEnvironment Include="forcerelocs" ForceRelocs="1" />
     <TestEnvironment Include="jitstress1" JitStress="1" />