Description
When BDN builds a MonoAOT project, it first does a regular dotnet build, then it does the MonoAOT compilation (source). These two builds both output to the same directory, and so there is a dependency that the MonoAOT compilation will overwrite the DLLs produced during the original dotnet build.
What we are seeing in the .NET perf lab is that a change caused the MonoAOT compilation to fail for our benchmarks, but BDN did not abort the benchmark run, and instead continued to run the benchmarks against the output from the original dotnet build, meaning it was instead measuring CoreCLR. There should be a check added to ensure that if the MonoAOT compilation fails that we do not continue running the benchmarks and return an error.
I don't have a good repro at the moment for this to debug it further, but will try get some more information soon after speaking with the Mono team.