[browser][coreCLR] JitInfoIsPopulated

[pavelsavara]

Contributes to #123224

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Tagging subscribers to this area: @BrzVlad, @janvorli, @kg
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[jkoritzinsky]

runtimevariant was added for Mono because the runtime would be built fundamentally differently depending on variant. That's not the case for how we build CoreCLR, so I don't think using it applies in the same way.

[Copilot]

Pull request overview

This PR contributes to issue #123224 by introducing a unified IsInterpreter property in PlatformDetection that combines checks for both Mono and CoreCLR interpreters, and updates test code to use this new property where appropriate.

Changes:

• Introduces IsInterpreter and IsNotInterpreter properties in PlatformDetection.cs that combine both IsMonoInterpreter and IsCoreClrInterpreter checks
• Updates test files to use the new IsInterpreter property or add IsCoreClrInterpreter checks where appropriate
• Improves consistency in interpreter detection across the test suite

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
src/libraries/Common/tests/TestUtilities/System/PlatformDetection.cs	Adds IsInterpreter and IsNotInterpreter properties that combine both interpreter types
src/libraries/System.Text.Json/tests/System.Text.Json.Tests/Utf8JsonReaderTests.cs	Updates TestDepth test to use IsInterpreter instead of IsMonoInterpreter
src/libraries/System.Text.Json/tests/System.Text.Json.Tests/AssemblyInfo.cs	Updates ActiveIssue attribute to use IsInterpreter instead of IsMonoInterpreter
src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/JitInfoTests.cs	Adds IsCoreClrInterpreter checks alongside existing IsMonoInterpreter checks

[pavelsavara]

It seems Mono interpreter has similar issues with time on other platforms too, not just browser.

Build linux-x64 Debug Mono_Interpreter_LibrariesTests

System.Runtime.Tests.JitInfoTests.JitInfoIsPopulated [FAIL]
      CompilationTime: after not greater than before! (after: 00:00:00.0059694, before: 00:00:00.0059694)
      Stack Trace:
        /_/src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/JitInfoTests.cs(75,0): at System.Runtime.Tests.JitInfoTests.JitInfoIsPopulated()
        /_/src/mono/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.Mono.cs(22,0): at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
        /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs(57,0): at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)

maccatalyst-arm64 Release AllSubsets_Mono_Smoke
maccatalyst-x64 Release AllSubsets_Mono_Smoke

[02:35:51] dbug: 2026-01-21 02:35:26.697 Df System.Runtime.Tests[73939:10814a] 	[FAIL] System.Runtime.Tests.JitInfoTests.JitInfoIsPopulated
[02:35:51] dbug: CompilationTime: after not greater than before! (after: 00:00:00, before: 00:00:00)
[02:35:51] dbug: at System.Runtime.Tests.JitInfoTests.JitInfoIsPopulated()
[02:35:51] dbug: 2026-01-21 02:35:26.697 Df System.Runtime.Tests[73939:10814a]    at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
[02:35:51] dbug: at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)
[02:35:51] dbug: 2026-01-21 02:35:26.698 Df System.Runtime.Tests[73939:10814a] System.Runtime.Tests.JitInfoTests 0.0011335 ms
[02:35:51] dbug: 2026-01-21 02:35:26.698 Df System.Runtime.Tests[73939:10814a]
[02:35:51] dbug: Test collection for System.Diagnostics.CodeAnalysis.Tests.FeatureSwitchDefinitionAttributeTests

[jkotas]

It seems Mono interpreter has similar issues with time on other platforms too, not just browser.

It looks more like this API is broken with Mono interpreter (it does not track time spent by JITing the methods to interpreter bytecode), nothing to do with timers.

[kg]

It seems Mono interpreter has similar issues with time on other platforms too, not just browser.

It looks more like this API is broken with Mono interpreter (it does not track time spent by JITing the methods to interpreter bytecode), nothing to do with timers.

We may have intentionally disabled it because sampling the current time in emscripten is extremely expensive. I vaguely recall doing something like that while optimizing startup in the past, though I can't guarantee that's what's going on here

[pavelsavara]

linux-x64 Debug Mono_Interpreter_LibrariesTests

System.Runtime.Tests.JitInfoTests.JitInfoIsPopulated [FAIL]
      Compiled IL bytes: after not greater than before! (after: 1341, before: 1341)
      Stack Trace:
        /_/src/libraries/System.Runtime/tests/System.Runtime.Tests/System/Runtime/JitInfoTests.cs(78,0): at System.Runtime.Tests.JitInfoTests.JitInfoIsPopulated()
        /_/src/mono/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.Mono.cs(22,0): at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
        /_/src/libraries/System.Private.CoreLib/src/System/Reflection/MethodBaseInvoker.cs(57,0): at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object obj, BindingFlags invokeAttr)