Delete DebugSymbols=true setting for the repo build

[jkotas]

This property does not do what its name says. The symbols are generated regardless of whether this property is true or false. What this property actually does is that it disables C# peephole IL optimizations.

This change results in ~0.5% IL binary size improvement thanks to the Roslyn IL peephole optimizations that it enables. Also, this gets us closer to default build configuration used by our users.

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[jkotas]

/azp run runtime-nativeaot-outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jkotas]

/azp run runtime-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jkotas]

/azp run runtime-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jkotas]

/azp run runtime-coreclr outerloop

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[am11]

This property does not do what its name says. The symbols are generated regardless of whether this property is true or false. What this property actually does is that it disables C# peephole IL optimizations.

https://learn.microsoft.com/en-us/visualstudio/msbuild/common-msbuild-project-properties?view=vs-2022 documents DebugSymbols as:

Setting -p:DebugSymbols=false on the command line disables generation of program database (.pdb) symbol files.

Does it mean documentation is incorrect or it's in fact an accidental bug?

[jkotas]

Does it mean documentation is incorrect or it's in fact an accidental bug?

I have opened dotnet/sdk#41364

My conclusion after reading through mentions of DebugSymbols property in dotnet/sdk repo is that it is a legacy mess that that should be avoided. DebugType property is what actually works.

[MichalStrehovsky]

Thanks!

[ViktorHofer]

For others reviewing this, the Microsoft.NET.Sdk makes this property still default to true when doing a Debug configuration build: https://github.com/dotnet/sdk/blob/ace21a69999eede779921900fca9420d37395aee/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.props#L49

[sbomer]

Based on #102392 (comment), should DebugSymbols=true also be removed from the SDK when building the Debug configuration, or is disabling some peephole optimizations useful for debugging?

[jkotas]

Possibly. It depends on whether and how the behavior of DebugSymbols is changed: dotnet/sdk#41364