Disable ICorProfiler on non-desktop and WASM platforms by AaronRobinsonMSFT · Pull Request #126550 · dotnet/runtime

AaronRobinsonMSFT · 2026-04-04T18:54:36Z

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Refactor FEATURE_CORPROFILER in clrfeatures.cmake to consolidate the ICorProfiler feature flag logic:

Disable ICorProfiler on non-desktop targets — Android, Mac Catalyst, iOS, and tvOS — in addition to WASM, since profiling is not supported on these platforms.
Make the flag overridable by wrapping it in if(NOT DEFINED FEATURE_CORPROFILER), allowing it to be set from the command line.
Remove the redundant WASM override that previously set FEATURE_CORPROFILER 0 separately.

Refactor FEATURE_CORPROFILER in clrfeatures.cmake to disable the ICorProfiler feature on Android, Mac Catalyst, iOS, and WASM targets. Previously the profiler was unconditionally enabled and then only explicitly disabled for WASM. This consolidates the logic into a single guard that excludes all unsupported platforms and makes the flag overridable from the command line. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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Pull request overview

Refactors the CoreCLR CMake feature-flag logic for FEATURE_CORPROFILER so ICorProfiler support is disabled by default on unsupported targets (mobile + WASM) while allowing command-line overrides.

Changes:

Wrap FEATURE_CORPROFILER defaulting in if(NOT DEFINED FEATURE_CORPROFILER) to allow CLI override.
Enable FEATURE_CORPROFILER only for non-WASM, non-mobile targets (Android, iOS, Mac Catalyst).
Remove the prior WASM-specific override that forcibly set FEATURE_CORPROFILER 0.

src/coreclr/clrfeatures.cmake

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

…WASM

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Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

src/coreclr/clrfeatures.cmake

AaronRobinsonMSFT · 2026-04-04T19:24:23Z

@jkotas @noahfalk I'm updating the logic here based on #126493 (comment).

jkotas · 2026-04-04T19:57:19Z

@dotnet/dotnet-diag Do we have any scenarios for ICorProfiler on iOS and Android? Is anything going to break if we drop it?

AaronRobinsonMSFT · 2026-04-04T21:43:39Z

@thaystg Please let me know if any of your prototypes need this to a degree that we should defer limiting it for the related platform.

thaystg · 2026-04-06T16:26:47Z

@thaystg Please let me know if any of your prototypes need this to a degree that we should defer limiting it for the related platform.

Correct, right now we totally depend on it. @noahfalk any suggestion about it?

thaystg · 2026-04-06T16:49:10Z

We need this enabled at least until preview 3.

noahfalk · 2026-04-07T00:21:22Z

@dotnet/dotnet-diag Do we have any scenarios for ICorProfiler on iOS and Android? Is anything going to break if we drop it?

Other than its use as the in-proc debugger loading mechanism I'm not aware of any other scenarios that require it. @thaystg - are you aware of anything else that requires it?

@noahfalk any suggestion about it?

What if we turned it off for WASM now, and turn it off for Android/iOS in a future preview once we've resolved the in-proc debugging loading?

noahfalk · 2026-04-07T00:30:15Z

[@jkotas] (#126493 (comment)) The question to ask is whether we want FEATURE_CORPROFILER for mobile platforms

I'm not aware of any 3rd parties specifically asking/planning to use it and it hasn't been there historically on Mono. I'd be happy to have it off for now and wait to see some clear evidence that profiler vendors want it on these platforms.

src/coreclr/clrfeatures.cmake

AaronRobinsonMSFT · 2026-04-07T15:04:25Z

What if we turned it off for WASM now, and turn it off for Android/iOS in a future preview once we've resolved the in-proc debugging loading?

Done.

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Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

src/coreclr/clrfeatures.cmake

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AaronRobinsonMSFT · 2026-04-08T18:07:35Z

/ba-g Unrelated failures

PR dotnet#126550 disabled FEATURE_CORPROFILER for tvOS but left iOS, MacCatalyst, and Android commented out (profiler still enabled). There is no reason to single out tvOS from its sibling Apple mobile platforms. They should be treated as a package deal. The uncommented 'AND NOT CLR_CMAKE_TARGET_TVOS' line removed profiler fields from the Thread struct on tvOS, making the hardcoded OFFSETOF__Thread__m_pInterpThreadContext in asmconstants.h wrong (0x2b8 vs actual 0x228), breaking all 3 tvOS legs in unified-build. Comment out the tvOS line to match iOS/MacCatalyst/Android, keeping the profiler enabled until all mobile platforms disable it together. Fixes internal unified-build tvOS failures on main (build 2946990). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

PR dotnet#126550 disabled FEATURE_CORPROFILER for tvOS but left Android, MacCatalyst, and iOS commented out as placeholders. This removed profiler fields from the Thread struct (m_pProfilerFilterContext, m_profilerCallbackState, m_dwProfilerEvacuationCounters — 144 bytes total), shifting m_pInterpThreadContext to a lower offset without updating asmconstants.h. This PR makes two changes: 1. **asmconstants.h**: Add PROFILING_SUPPORTED conditionals to select the correct m_pInterpThreadContext offset when profiling is disabled (0x228 Release, 0xa90 Debug on Unix). 2. **clrfeatures.cmake**: Uncomment the Android, MacCatalyst, and iOS exclusions so all non-desktop platforms consistently disable FEATURE_CORPROFILER. Since asmconstants.h now handles both the profiler and no-profiler cases, these platforms can safely disable profiling without hitting the same offset mismatch. Fixes internal unified-build failures on tvOS legs (tvOS_Shortstack_arm64, tvOSSimulator_Shortstack_x64, tvOSSimulator_Shortstack_arm64) on main. Build: https://dev.azure.com/dnceng/internal/_build/results?buildId=2946990 Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

PR dotnet#126550 disabled FEATURE_CORPROFILER for tvOS but left iOS, MacCatalyst, and Android commented out (profiler still enabled). There is no reason to single out tvOS from its sibling Apple mobile platforms. They should be treated as a package deal. The uncommented 'AND NOT CLR_CMAKE_TARGET_TVOS' line removed profiler fields from the Thread struct on tvOS, making the hardcoded OFFSETOF__Thread__m_pInterpThreadContext in asmconstants.h wrong (0x2b8 vs actual 0x228), breaking all 3 tvOS legs in unified-build. Comment out the tvOS line to match iOS/MacCatalyst/Android, keeping the profiler enabled until all mobile platforms disable it together. Fixes internal unified-build tvOS failures on main (build 2946990). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

) PR #126550 disabled `FEATURE_CORPROFILER` for tvOS (`AND NOT CLR_CMAKE_TARGET_TVOS` uncommented) but left iOS, MacCatalyst, and Android commented out (profiler still enabled). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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AaronRobinsonMSFT and others added 2 commits April 4, 2026 12:13

Also exclude tvOS from ICorProfiler support

3b4f873

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

Update ICorProfiler support check to exclude non-desktop targets and …

7b5e7fc

…WASM

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AaronRobinsonMSFT changed the title ~~Disable ICorProfiler on mobile and WASM platforms~~ Disable ICorProfiler on non-desktop and WASM platforms Apr 4, 2026

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AaronRobinsonMSFT requested review from jkotas and noahfalk April 4, 2026 19:22

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AaronRobinsonMSFT added the arch-wasm WebAssembly architecture label Apr 4, 2026

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This was referenced Apr 7, 2026

The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#3008

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[android-arm64] The Operation will be canceled. The next steps may not contain expected logs. dotnet/dnceng#6408

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Merge branch 'main' into disable-profiler-on-mobile

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build-analysis bot mentioned this pull request Apr 8, 2026

Error reported in diagnostic logs. Please examine the log for more details dotnet/dnceng#1928

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Merge branch 'main' into disable-profiler-on-mobile

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Unable to pull image from mcr.microsoft.com #117164

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AaronRobinsonMSFT merged commit 0fc6976 into dotnet:main Apr 8, 2026
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AaronRobinsonMSFT deleted the disable-profiler-on-mobile branch April 8, 2026 18:08

dotnet-maestro bot mentioned this pull request Apr 9, 2026

[main] Source code updates from dotnet/runtime dotnet/dotnet#5943

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akoeplinger mentioned this pull request Apr 9, 2026

Fix Thread offset for non-desktop platforms without FEATURE_CORPROFILER #126710

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steveisok mentioned this pull request Apr 9, 2026

Re-enable FEATURE_CORPROFILER for tvOS to match iOS/MacCatalyst #126715

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