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Opt out of metadata trimming - #2020
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Benchmark.NET opts itself into trimming, but it's trim compatible only by accident (it's reflecting on things that are statically referenced and therefore would be kept by IL-based trimming solutions). NativeAOT is able to trim metadata more aggressively - e.g. an accessed field might still have its name and metadata removed and the only thing that is kept is a location in memory that can be read and written. I'm now seeing Benchmark.NET failing with latest ILCompiler packages after dotnet/runtime#70201 that enabled more aggressive trimming. Benchmark.NET should ideally `<EnableTrimAnalyzer>true</EnableTrimAnalyzer>` in the BenchmarkDotNet.csproj project and fix all the warnings and the problem will go away. But enabling compat mode should help too.
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The failure looks like this. Normally this would be some silent weird behavior (because the field just be missing), but BenchmarkDotNet is opting into |
adamsitnik
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LGTM, thank you @MichalStrehovsky !
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Another attempt at fixing the problem I tried to fix in dotnet#2020. In that pull request, I reflection-rooted all of BenchmarkDotNet, but that looks like it increases the size of the closure too much (dotnet/performance#2532). So here I'm rolling that part back and annotating enough of the `Characteristic` APIs to make it so that we shouldn't run into the original problem. I basically added `<EnableTrimAnalyzer>true</EnableTrimAnalyzer>` to the BechmarkDotNet project, looked at the trimming warning in https://github.com/dotnet/BenchmarkDotNet/blob/63e28c100a42a6492d09a0b93a8a4c141061bb0d/src/BenchmarkDotNet/Characteristics/CharacteristicHelper.cs#L49-L68 where we were getting the crash and kept getting annotations until it stopped generating new warnings. We now have an annotation in a spot that should make sure the `Job` class has all fields and properties kept (it's used with one of the annotated `Create` methods). There are more trimming warnings that I didn't try to solve because they're unrelated to the problem at hand.
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* Make a bit of BenchmarkDotNet trimmable Another attempt at fixing the problem I tried to fix in #2020. In that pull request, I reflection-rooted all of BenchmarkDotNet, but that looks like it increases the size of the closure too much (dotnet/performance#2532). So here I'm rolling that part back and annotating enough of the `Characteristic` APIs to make it so that we shouldn't run into the original problem. I basically added `<EnableTrimAnalyzer>true</EnableTrimAnalyzer>` to the BechmarkDotNet project, looked at the trimming warning in https://github.com/dotnet/BenchmarkDotNet/blob/63e28c100a42a6492d09a0b93a8a4c141061bb0d/src/BenchmarkDotNet/Characteristics/CharacteristicHelper.cs#L49-L68 where we were getting the crash and kept getting annotations until it stopped generating new warnings. We now have an annotation in a spot that should make sure the `Job` class has all fields and properties kept (it's used with one of the annotated `Create` methods). There are more trimming warnings that I didn't try to solve because they're unrelated to the problem at hand.
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Benchmark.NET opts itself into trimming, but it's trim compatible only by accident
(it's reflecting on things that are statically referenced and therefore would be kept by IL-based trimming solutions). NativeAOT is able to trim metadata more aggressively - e.g. an accessed field might still have its name and metadata removed and the only thing that is kept is a location in memory that can be read and written.I'm now seeing Benchmark.NET failing with latest ILCompiler packages after dotnet/runtime#70201 that enabled more aggressive trimming.It's reflecting on a field that is not used in any other way than by unanalyzable reflection. We would previously keep all fields, irrespective of whether they're used on reflected on dotnet/runtime#70546.
Benchmark.NET should ideally
<EnableTrimAnalyzer>true</EnableTrimAnalyzer>in the BenchmarkDotNet.csproj project and fix all the warnings and the problem will go away. But enabling compat mode should help too.