How does this work with CMake & MSVC, without Ninja?

[Zephilinox]

I ran the following command in powershell

cmake -DCMAKE_C_COMPILER_LAUNCHER=sccache -DCMAKE_CXX_COMPILER_LAUNCHER=sccache ..

it finds MSVC

-- Building for: Visual Studio 16 2019
-- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.18363.
-- The CXX compiler identification is MSVC 19.27.29112.0
-- The C compiler identification is MSVC 19.27.29112.0
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.27.29110/bin/Hostx64/x64/cl.exe
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.27.29110/bin/Hostx64/x64/cl.exe -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.27.29110/bin/Hostx64/x64/cl.exe
-- Check for working C compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/Community/VC/Tools/MSVC/14.27.29110/bin/Hostx64/x64/cl.exe -- works

after running cmake --build . --config Release (once or more) the number of cache hits/misses is unchanged (from previous attempts at this)

p:\some_proj\build>sccache --show-stats
Compile requests                   1177
Compile requests executed           966
Cache hits                           19
Cache hits (C/C++)                   19
Cache misses                        887
Cache misses (C/C++)                887
Cache timeouts                        0
Cache read errors                     0
Forced recaches                       0
Cache write errors                    0
Compilation failures                 58
Cache errors                          2
Cache errors (C/C++)                  2
Non-cacheable compilations          874
Non-cacheable calls                 211
Non-compilation calls                 0
Unsupported compiler calls            0
Average cache write               0.010 s
Average cache read miss           0.006 s
Average cache read hit            0.001 s
Failed distributed compilations       0

Non-cacheable reasons:
Can't handle UnknownFlag arguments with -Xclang     211

Cache location                  Local disk: "C:\\Users\\Zeph\\AppData\\Local\\Mozilla\\sccache\\cache"
Cache size                            3 MiB
Max cache size                       10 GiB

with Ninja, it looks like sccache is being used (but still doesn't work correctly, see other issues I've opened)

[ranjithp04]

@Zephilinox am facing this same problem. Did you found a solution for this ?

[bmyates]

I'm currently also having this issue. Any advice would be great.

[Zephilinox]

sorry, I never found a solution. sccache was always flaky, even when I did end up using Ninja as described here #956 with /Z7

[congzhangzh]

Only makefile&ninja be supported? As this fit the rule of static input and expected output, which is cache possible

Ref: 1. https://cmake.org/cmake/help/latest/prop_tgt/LANG_COMPILER_LAUNCHER.html
2. https://gitlab.kitware.com/cmake/cmake/-/issues/19326
3. https://abseil.io/resources/swe-book/html/ch18.html
4. ccache/ccache#1038
5. https://medium.com/@parakram.majumdar/ccache-with-msbuild-devenv-f286778e0be7

[congzhangzh]

@bmyates @Zephilinox Hi, maybe this help?

https://github.com/medlab/daily-scripts-4-us/tree/main?tab=readme-ov-file#speed-you-windows-c-build-by-ccache-like-tools
https://github.com/ccache/ccache/wiki/MS-Visual-Studio