How to debug coreclr with clion at the source level

[successgo]

I have tried a lot and I can't set breakpoint inside coreclr, like EEStartup method.

The answer is build with option --keepnativesymbols true.

What I have done so far:

Get the code

Head to https://github.com/dotnet/runtime/releases , download .NET 9 RC 2 and unzip it.

Full build in terminal

Use clang@16, apple clang or brew clang both are working, but brew clang@19 will crash.

./build.sh --ninja

coreclr build artifacts are inside artifacts/bin/coreclr/osx.arm64.Debug, I'll call this dir CORE_ROOT.

I need to copy libSystem.Native.dylib and System.Runtime.dll to the CORE_ROOT dir which mentioned above.

Open with CLion

I'm using apple m3.

Need to apply a patch of CMakePresets.json first, it's https://github.com/dotnet/runtime/pull/109061/files.

Open CLion and coreclr directory, it will recognize it as cmake project, and enable the preset profile osx.arm64.Debug.

Attempt 1 debug corerun`main

Success.

Open target corerun, set program arguments to /path/to/your/dotnet-app.dll, and environment variable CORE_ROOT=/path/to/artifacts/bin/coreclr/osx-arm64-Debug and CORE_LIBRARIES=/path/to/artifacts/bin/runtime/net9.0-osx-Debug-arm64.

Now set the breakpoint for main function, hit Debug button, here we go:

Attempt 2 debug coreclr`EEStartup

Failed.

Open target coreclr, set program arguments to /path/to/your/dotnet-app.dll, and environment variable CORE_ROOT=/path/to/artifacts/bin/coreclr/osx-arm64-Debug and CORE_LIBRARIES=/path/to/artifacts/bin/runtime/net9.0-osx-Debug-arm64.

Now set the breakpoint for EEStartup function, hit Debug button, here we go:

It just run to end, without hitting the breakpoint.

[huoyaoyuan]

The steps performed looks similar to steps for Visual Studio. I'm not familiar with CLion.

I need to copy libSystem.Native.dylib and System.Runtime.dll to the CORE_ROOT dir which mentioned above.

They are set by the environment variable CORE_LIBRARIES.

Some potential troubleshooting approaches:

• Does CLion has a "break point can't be set" message? When the symbols are missing/mismatched, or the dylib hasn't be loaded yet.
• What about single stepping through corerun?
• Does corerun runs everything successfully?

[huoyaoyuan]

But it indeed show the message below while running corerun:

This should be the problem. CLion is not associating the symbol of libcoreclr.dylib with the source. It only correctly sets up debugging for the entry executable corerun.

It's now IDE specific stuff and you have to learn about how CLion loads debug symbol.

[successgo]

Thanks @huoyaoyuan for pointing out the new clue.

[successgo]

I got a work around here.

By adding / loading .dwarf inside lldb manually, it works.

[successgo]

  [817/1739] Linking CXX shared library dlls/mscoree/coreclr/libcoreclr.dylib
  Stripping symbols from libcoreclr.dylib into libcoreclr.dylib.dwarf

I found these Stripping lines in the output of build.

I found there is an option to configure if keep the native symbols or not, which is --keepnativesymbols, but previously I can not build with this option, now I figured it out with option --keepnativesymbols true.

The complete build command is

./build.sh --ninja --keepnativesymbols true

After build like this, breakpoint debugging inside coreclr works well.

[huoyaoyuan]

You can also try to explore how to make CLion load stripped symbol by default. It's often more useful to debug with the exact same build configuration used for the repository.

[successgo]

Sure.

I found this https://lldb.llvm.org/use/ondemand.html, I'll give it a try later. No lucky.

I found there is an issue open #92911.

[EgorBo]

@successgo it'd be nice to have a documentation on how to setup CLion checked in. We don't have a good story on non-windows fior this