Enable clcache in CMakeLists.txt

[Zerophase]

For make and other Linux build systems ccache works with set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache) For nmake this doesn't work. Is there a means of enabling clcache through a variable in CMakeLists.txt?

[ivaigult]

You can try to hack CLToolExe and CLToolPath properties for every target.

function(any_target_hook)
    set(NON_COMPILE_TARGETS INTERFACE IMPORTED UNKNOWN ALIAS) 
    list(FIND NON_COMPILE_TARGETS "${ARGV1}" found)
    if (${found} GREATER -1)
        return()
    endif()
        
    set_target_properties(${ARGV0} PROPERTIES VS_GLOBAL_CLToolExe         "clcache.exe")
    set_target_properties(${ARGV0} PROPERTIES VS_GLOBAL_CLToolPath        "${CLCACHE_DIR}")
    set_target_properties(${ARGV0} PROPERTIES VS_GLOBAL_TrackFileAccess  "false")
endfunction()

function(add_library)
     _add_library(${ARGN})
     any_target_hook(${ARGN})
endfunction()

function(add_executable)
     _add_executable(${ARGN})
     any_target_hook(${ARGN})
endfunction()

[ivaigult]

Oh, wait. This works only for msbuild.

[Zerophase]

hmm, I'm using jom currently, since it seems to give the best build times. Chasing after those build times below a second.

[frerich]

Some StackOverflow answer suggests that, as of CMake 3.4, passing something like

-DCMAKE_CXX_COMPILER_LAUNCHER=clcache

on the command line may work. It's not clear to me though whether this also works with NMake.

I suspect this question may yield better replies when asked in some CMake forum - unfortunately, I'm not very familiar with CMake myself.

[frerich]

In case you find something though, it would be great if you could share your finding such that we could add it to the Wiki.

[frerich]

@Zerophase Did you find any way to make this work with CMake? I'd like to close this ticket since I suspect that there's not much to be done here but if you found something interesting, I'd love to add that to the Wiki for other clcache users to benefit from. :-)

[Zerophase]

@frerich It might be working I got it to compile, but I'm not sure if it's actually using clcache.

This breaks compilation:

set(CMAKE_CXX_COMPILER_LAUNCHER "path/to/clcache.exe")

This allows the project to compile, but I don't know if clcache is actually getting run: (I use the same for ccache)

set(GLOBAL PROPERTY RULE_LAUNCH_COMPILE "path/to/clcache.exe")
set(GLOBAL PROPERTY RULE_LAUNCH_LINK "path/to/clcache.exe")

I'm using the prebuilt zip, by the way.

[frerich]

@Zerophase You could check whether clcache kicks in by checking the stats before & after a build (by running clcache -s).

[Zerophase]

Yeah, it doesn't kick in.

[frerich]

Pity - I'm closing this issue, I suspect it's more suitable for a CMake forum.

[mossheim]

Hey, see this blog post: https://crascit.com/2016/04/09/using-ccache-with-cmake/. RULE_LAUNCH_COMPILE and CMAKE_CXX_COMPILER_LAUNCHER don't work with non-Ninja/Makefile generators, so people have run into a similar problem using XCode on macOS. We use the workaround for XCode in our project (supercollider/supercollider#3136) and I bet it has a good chance of working on Windows with clcache. I haven't tried it yet, but I was thinking of giving it a go when I set up appveyor for our project.

[feliwir]

This is not a CMake issue, but much more a design issue of clcache. Your integration page states that CC/CXX environment variables should be set before running cmake, but it should definetly be possible to tell cmake to use clcache from within a CMakeList, As stated before with ccache this is possible like this: set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache), which puts ccache before the actual compile command. CCache should behave similar and not try to find CL.exe by itself in my opinion.

[akleber]

ccache works by prefixing the compile command or masquerading as the compiler. clcache only supports masquerading.
CMake's CMAKE_CXX_COMPILER_LAUNCHER variable or RULE_LAUNCH_COMPILE property prefix the compiler with this command.
So as CMake only supports the prefix method and clcache only supports the masquerade method, CMAKE_CXX_COMPILER_LAUNCHER/RULE_LAUNCH_COMPILE does not work with clcache currently.
For me the integration method via "wrapper batch file" described in the wiki https://github.com/frerich/clcache/wiki/Integration works fine. However for an even smoother CMake integration I would love to see the prefixing method in clcache.