conan support

[blockspacer]

Proof-of-concept https://github.com/blockspacer/llvm_tools
(MIT license)

Goal: easy install include-what-you-use with conan install command.

After conan install you will be able to use cmake find_program like so:

find_program(IWYU include-what-you-use
  PATHS
    ${CONAN_BIN_DIRS}
    ${CONAN_BIN_DIRS_LLVM_TOOLS}
  NO_SYSTEM_ENVIRONMENT_PATH
  NO_CMAKE_SYSTEM_PATH
)
if(NOT IWYU)
  message(FATAL_ERROR "IWYU not found")
endif()

Note that conan supports not only cmake (for example, scons also can be used)

See for details about conan https://docs.conan.io/en/latest/getting_started.html

[kimgr]

@blockspacer Sounds cool. There's nothing we need to do from the upstream IWYU side, right? Feel free to package IWYU for conan.

[blockspacer]

Usage example for cmake users:

https://github.com/blockspacer/cmake_helper_utils_conan/blob/0e2ce31820fff0045d7228614afe8c084ee73af5/cmake/Findcmake_helper_utils.cmake#L2373

https://github.com/blockspacer/flextool/blob/da4cb5e7d44c7b205328923b018f5caee3282642/cmake/setup_iwyu.cmake

https://github.com/blockspacer/flextool/blob/da4cb5e7d44c7b205328923b018f5caee3282642/tools/run_tool.cmake#L366

Install IWYU (ENABLE_LLVM_TOOLS=TRUE):

cmake \
  -DEXTRA_CONAN_OPTS=\
"--profile;clang\
;-s;build_type=Debug\
;-s;cling_conan:build_type=Release\
;-s;llvm_tools:build_type=Release\
;--build;missing" \
  -DENABLE_LLVM_TOOLS=TRUE \
  -DENABLE_CLING=TRUE \
  -DENABLE_FLEXTOOL=TRUE \
  -DENABLE_FLEX_REFLECT_PLUGIN=TRUE \
  -DENABLE_SQUARETS=TRUE \
  -DENABLE_FLEX_SQUARETS_PLUGIN=TRUE \
  -DENABLE_FLEX_PIMPL_PLUGIN=TRUE \
  -DENABLE_FLEX_TYPECLASS_PLUGIN=TRUE \
  -DENABLE_FLEX_META_PLUGIN=TRUE \
  -DENABLE_FLEX_META_DEMO=TRUE \
  -P tools/buildConanThirdparty.cmake

Run IWYU:

# creates local build in separate folder and runs cmake targets
cmake -DIWYU="ON" -DCLEAN_OLD="ON" -P tools/run_tool.cmake

[blockspacer]

I was stuck with IWYU could not find stddef.h issue
#679

and found that i can bundle required includes with conan package (llvm)

Now i pass to IWYU:

    -nostdinc++
    -nodefaultlibs
    -isystem${CONAN_LLVM_TOOLS_ROOT}/include/c++/v1/
    -isystem${CONAN_LLVM_TOOLS_ROOT}/lib/clang/10.0.1/include/