Clang Tidy Support

[calgray]

This change configures clang-tidy to scan only the project source files and report issues in travis-ci. Linting can be performed by running make lint.

[calgray]

Linting is passing with no expected behaviour changes. There are only some narrowing conversion violations that need to be addressed in a separate PR to check for correctness and performance. Tests are failing due to travisCI timing out.

clang-tidy-10 -p=/home/calgray/Code/icrar/leap-accelerate/build/Release -quiet /home/calgray/Code/icrar/leap-accelerate/src/icrar/leap-accelerate/model/cpu/MetaData.cc
/home/calgray/Code/icrar/leap-accelerate/src/icrar/leap-accelerate/model/cpu/MetaData.cc:49:34: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [cppcoreguidelines-narrowing-conversions]
        m_constants.nbaselines = ms.GetNumBaselines();
                                 ^
/home/calgray/Code/icrar/leap-accelerate/src/icrar/leap-accelerate/model/cpu/MetaData.cc:61:28: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [cppcoreguidelines-narrowing-conversions]
        m_constants.rows = ms.GetNumRows();
                           ^
/home/calgray/Code/icrar/leap-accelerate/src/icrar/leap-accelerate/model/cpu/MetaData.cc:62:32: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [cppcoreguidelines-narrowing-conversions]
        m_constants.num_pols = ms.GetNumPols();
                               ^
/home/calgray/Code/icrar/leap-accelerate/src/icrar/leap-accelerate/model/cpu/MetaData.cc:63:32: warning: narrowing conversion from 'unsigned int' to signed type 'int' is implementation-defined [cppcoreguidelines-narrowing-conversions]
        m_constants.stations = ms.GetNumStations();
                               ^
79224 warnings generated.

[rtobar]

BTW, I just tried this locally and found that the lint target created by cmake is bogus: it runs clang-tidy with an explicit set of checks rather than using your .clang-tidy file. My suggestion would be:

• Remove the lint target from the cmake machinery, including the inclusion of the external/cmake-modules, which should simplify things a bit
• Use instead the built-in cmake (3.6+ I think, you already require 3.8 so should be good) support for clang-tidy in your new Travis job when you do the linting:
  • When running cmake just add -DCMAKE_CXX_CLANG_TIDY=clang-tidy
  • Then when building clang-tidy will run automatically as part of the build

[calgray]

I have clang-tidy running both via a target and as part of cmake locally but I don't think it ran in the last build. For the CMake target I've been using the following modified lint.cmake script:

if(NOT TARGET lint)
    find_program(RUN_CLANG_TIDY
        NAMES 
            run-clang-tidy
        PATHS
            /usr/local/opt/llvm/bin
    )

    if (NOT RUN_CLANG_TIDY)
        message(WARNING "run-clang-tidy not found - no lint target")
    else()
        message(STATUS "run-clang-tidy found adding lint target")

        file(GLOB_RECURSE ALL_SOURCE_FILES
            ${PROJECT_SOURCE_DIR}/src/*.cc
            ${PROJECT_SOURCE_DIR}/src/*.h
        )

        add_custom_target(lint
            COMMAND ${RUN_CLANG_TIDY} -j 4 -quiet
            ${ALL_SOURCE_FILES}
            WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
            ${INCLUDE_DIRECTORIES}
        )
    endif()
endif()

[calgray]

I've added two approaches to linting in the CI pipeline. One is via the built in cmake support that lints while building and increases build time from 12m to 18m with a 2 thread parallel build. The other approach is with a lint-only target using run-clang-tidy that takes 15m (but it seems the -j 2 flag currently does not work for run-clang-tidy.py).

I'm happy to use either in CI or development and document how each can be used by project devs.

It's worth noting that clang-tidy doesn't currently run on cuda code as it generates warning related to shader and architecture versions, there is some discussion about this online but I haven't yet found a clean solution to supporting it.