How to use include-what-you-use in my cpp project (win)?

Question

Noob question here, but I can manage to install include-what-you-use... Which files do I need to download and which is the correct folder I need to point CMAKE_PREFIX_PATH to? Or is there another way to use iwyu without building it myself? I want to be able to use iwyu in my cmake project. I need to build on windows.

I switched to the clang_15 branch, downloaded and unzipped clang+llvm-15.0.0-amd64-pc-solaris2.11.tar.xz from https://github.com/llvm/llvm-project/releases/tag/llvmorg-15.0.0 and ran cmake, but it throws this error multiple times:

CMake Error at C:/Users/morit/Documents/dev/iwyu/clang+llvm-15.0.0-amd64-pc-solaris2.11/clang+llvm-15.0.0-amd64-pc-solaris2.11/lib/cmake/llvm/AddLLVM.cmake:932 (add_executable):
  Target "include-what-you-use" links to target "ZLIB::ZLIB" but the target
  was not found.  Perhaps a find_package() call is missing for an IMPORTED
  target, or an ALIAS target is missing?
Call Stack (most recent call first):
  CMakeLists.txt:101 (add_llvm_executable)

downloading LLVM-15.0.0-win64.exe also does not work...

I ran cmake with cmake -S . -B build "-DCMAKE_PREFIX_PATH=C:\Program Files\LLVM" (from source tree, with build as build folder) I do not want to build clang myself since this would take ages.

Answer 1

The issue you are most likely experiencing is that you are using binaries build with a specific compiler A. Yet you are building a project with a different compiler B and trying to include the binaries from compiler A.

This won't work, because the binaries are different! You need to use the same compiler for both your libraries and your current project. This is most likely the reason why your CMake can't find an existing and installed library.

EDIT: If you are using the same compiler. Then the issue is as the error states due to a missing dependency ZLIB.

EDIT2: To answer your question regarding CMAKE_PREFIX_PATH you should forget about it and instead update your CMAKE_MODULE_PATH which is a list variable. This variable should contain the path to the findZLIB.cmake files (respectively findXYZ.cmake files of the given dependency). The author of the library should include the list of dependencies he uses and if not you can check out the CMakeLists.txt file for the information you need.