Adding LLVM to my Cmake Project: Why are there hardcoded paths in LLVM's Cmake file?

Question

I'm using LLVM/Clang in my C++ project. I can build and run everything fine with a Makefile.

I'm now trying to move to Cmake and I can't get things to work. Let me explain what I've done.

I'm following this tutorial:

http://llvm.org/docs/CMake.html#embedding

A relevant snippet from that webpage is:

From LLVM 3.5 onwards both the CMake and autoconf/Makefile build systems export LLVM libraries as importable CMake targets.

Great! I'll go download LLVM 3.5 and I should be good to go. I went to the download page:

http://llvm.org/releases/download.html

and downloaded the pre-built binaries for Clang for Ubuntu 14.04 Linux.

Then, I added the following to my CMakeLists.txt file:

find_path (LLVM_DIR LLVM-Config.cmake
     /home/dev/Downloads/clang+llvm-3.5.0-x86_64-linux-gnu/share/llvm/cmake
         )
message(STATUS "LLVM_DIR = ${LLVM_DIR}")
find_package(LLVM REQUIRED CONFIG)

(This is the same as the tutorial, except I set LLVM_DIR since it is currently in a non-standard location.)

When I run cmake, I get the following error:

[dev@beauty:/path/to/project/build (develop)] $ cmake ..
-- LLVM_DIR = /home/dev/Downloads/clang+llvm-3.5.0-x86_64-linux-gnu/share/llvm/cmake
CMake Error at /home/dev/Downloads/clang+llvm-3.5.0-x86_64-linux-gnu/share/llvm/cmake/LLVMConfig.cmake:50 (include):
  include could not find load file:

    /home/ben/development/llvm/3.5/final/Phase3/Release/llvmCore-3.5.0-final.install/share/llvm/cmake/LLVMExports.cmake
Call Stack (most recent call first):
  CMakeLists.txt:14 (find_package)


CMake Error at /home/dev/Downloads/clang+llvm-3.5.0-x86_64-linux-gnu/share/llvm/cmake/LLVMConfig.cmake:53 (include):
  include could not find load file:

    /home/ben/development/llvm/3.5/final/Phase3/Release/llvmCore-3.5.0-final.install/share/llvm/cmake/LLVM-Config.cmake
Call Stack (most recent call first):
  CMakeLists.txt:14 (find_package)

So Cmake seems to be finding LLVM's Cmake file, but Cmake is complaining about some path starting with /home/ben/.

Indeed, it appears that LLVM's LLVMConfig.cmake file has some absolute paths in it that are not relevant for my machine. For example:

[dev@beauty:~/Downloads/clang+llvm-3.5.0-x86_64-linux-gnu ] $ head ./share/llvm/cmake/LLVMConfig.cmake
# This file provides information and services to the final user.

set(LLVM_INSTALL_PREFIX "/home/ben/development/llvm/3.5/final/Phase3/Release/llvmCore-3.5.0-final.install")

set(LLVM_VERSION_MAJOR 3)
set(LLVM_VERSION_MINOR 5)
set(LLVM_VERSION_PATCH 0)
set(LLVM_PACKAGE_VERSION 3.5.0)

set(LLVM_COMMON_DEPENDS )

Who's ben and what's he doing in this file? He shows up in a few more places:

[dev@beauty:~/Downloads/clang+llvm-3.5.0-x86_64-linux-gnu ] $ grep ben ./share/llvm/cmake/LLVMConfig.cmake
set(LLVM_INSTALL_PREFIX "/home/ben/development/llvm/3.5/final/Phase3/Release/llvmCore-3.5.0-final.install")
set(LLVM_INCLUDE_DIRS "/home/ben/development/llvm/3.5/final/Phase3/Release/llvmCore-3.5.0-final.install/include")
set(LLVM_LIBRARY_DIRS "/home/ben/development/llvm/3.5/final/Phase3/Release/llvmCore-3.5.0-final.install/lib")
set(LLVM_CMAKE_DIR "/home/ben/development/llvm/3.5/final/Phase3/Release/llvmCore-3.5.0-final.install/share/llvm/cmake")
set(LLVM_TOOLS_BINARY_DIR "/home/ben/development/llvm/3.5/final/Phase3/Release/llvmCore-3.5.0-final.install/bin")

Needless to say, those paths do not exist on my machine. I'm confused as to why these files have these paths in them? Am I supposed to run a tool or something to change these paths for my machine? Or do I need to change them all manually?

EDIT: Out of curiosity, I manually changed all those paths to point to paths on my machine:

[dev@beauty:~/Downloads/clang+llvm-3.5.0-x86_64-linux-gnu/share/llvm/cmake ] $ sed -i -e's/.home.ben.development.llvm.3.5.final.Phase3.Release.llvmCore-3.5.0-final.install/\/home\/dev\/Downloads\/clang+llvm-3.5.0-x86_64-linux-gnu/g' *

After that, Cmake no longer complained and my build proceeded.

I'd still like to know why I needed to do that.

Answer 1

Sounds like a LLVM bug. Feel free to enter it: http://llvm.org/bugs