Vscode-cmake-tools: Can't debug in Visual Studio Code

[zhouhao27]

Brief Issue Summary

Can't make the Visual Studio Code debugger work.

Expected:

1. Run CMake Configuration

The result:

[cmake] Configuring done
[cmake] CMake Deprecation Warning:
[cmake]   The 'cmake-server(7)' is deprecated.  Please port clients to use the
[cmake]   'cmake-file-api(7)' instead.
[cmake] 
[cmake] 
[cmake] Generating done

1. Select Clang 11.0

1. Allow IntelliSense for this folder

1. Build

The result:

[build] Starting build
[proc] Executing command: /usr/local/bin/cmake --build /Users/xxx/Desktop/cmake/hello/build --config Debug --target all -- -j 6
[build] Scanning dependencies of target say-hello
[build] [ 25%] Building CXX object CMakeFiles/say-hello.dir/hello.cpp.o
[build] [ 50%] Linking CXX static library libsay-hello.a
[build] [ 50%] Built target say-hello
[build] Scanning dependencies of target hello
[build] [ 75%] Building CXX object CMakeFiles/hello.dir/main.cpp.o
[build] [100%] Linking CXX executable hello
[build] [100%] Built target hello
[build] Build finished with exit code 0

1. Set the break point and run Debug

Apparent Behavior:

1. It seems the editor hangs
2. The information in Output

[build] Starting build
[proc] Executing command: /usr/local/bin/cmake --build /Users/xxx/Desktop/cmake/test/build --config Debug --target hello -- -j 6
[build] [ 50%] Built target say-hello
[build] [100%] Built target hello
[build] Build finished with exit code 0
[proc] Executing command: /usr/bin/lldb-mi --version
[proc] Executing command: /usr/bin/gdb --version
[proc] Executing command: /usr/bin/lldb --version
[proc] Executing command: /usr/bin/lldb --version

Platform and Versions

• Operating System: macOS 10.15
• CMake Version: 3.15.5
• VSCode Version: 1.40.2
• CMake Tools Extension Version: 1.2.3
• Compiler/Toolchain: Xcode

[Hadatko]

As long as i know cmake is only for building final image/binary. You need install extension for debugging for device you want to. E.g. i am debugging arm embedded device so i am using gdb debugger or cortex debugger.

[bobbrow]

Are you hitting this issue? https://github.com/microsoft/vscode-cpptools/issues/3829
We're working on it (with the C++ extension).

[zhouhao27]

@bobbrow Yes, I have the same issue. Thanks for your information.

Based on this youtube video, we even don't need to setup launch.json or task.json to debug. Is that true?

[bobbrow]

That is correct. You shouldn't need a launch.json or tasks.json. If you do need to override a setting for debugging, you can use the cmake.debugConfig setting.

[kaidokert]

The problem is this:

[proc] Executing command: /usr/bin/lldb --version

The default lldb gets picked, which will not work. The launch command of /usr/bin/lldb --interpreter=mi will just fail with

Starting: "/usr/bin/lldb" --interpreter=mi
lldb: unrecognized option `--interpreter=mi'

The root of the issue is in this fallback codepath in this plugin: https://github.com/microsoft/vscode-cmake-tools/blob/50fc5ba265ee13f53dc9f273d0f1635c8861bd7d/src/debugger.ts#L163

If your compiler is "/usr/bin/clang" it tries to use "/usr/bin/lldb" as a debugger, and does not respect the "miDebuggerPath" setting in launch.json ( as launch.json might not even exist here ).

It works fine when hardcoding something like : let clang_debugger_path = '/Applications/Xcode.app/Contents/Developer/usr/bin/lldb-mi'; instead, which is what the plugin code should probably be trying by default, or alternatively look for lldb-mi provided by vscode-cpptools

Also, the default miDebuggerPath should probably be a global setting for this plugin, which would get used when launch.json doesn't exist and built-in guesses fail.

[bobbrow]

FYI, miDebuggerPath can be set via the cmake.debugConfig setting:

    "cmake.debugConfig": {
        "miDebuggerPath": "/path/to/lldb-mi"
    },

[hroumani]

@bobbrow your suggestion did the trick for me, before I applied that:
[main] Starting debugger with following configuration. ... "miDebuggerPath":"gdb"

So it was effectively ignoring:
"miDebuggerPath": "C:\\Program Files (x86)\\mingw-w64\\i686-8.1.0-posix-dwarf-rt_v6-rev0\\mingw32\\bin\\gdb.exe"

In launch.json.