[POC] use compiled mesa host tools

[heitbaum]

With the builds increasing by ~1hr due to mesa:host tools needing to be compiled with panfrost, this proof of concept is the start of a toolchain to speed up the build process.

Initial version takes the 3 binaries from a GH repo and unpacks them into toolchain when mesa:host would need to be called.

things to work though:

• flag if tools are to be built or downloaded
• What if tools arent available - self build?
• Use xzexe for the tools to allow distribution (this is currently the case)
• GHA job to build the tools
• What constitutes change and tools to be rebuilt
• …

A little bit of experimentation has lead to the following files (for the mesa:host build.) The shared libraries are required only by mesa_clc when built normally, but if mesa:host is built with -Dshared-llvm=disabled then mesa_clc increases in size to 150M (36M xz compressed.) a saving of 60M (11M compressed). These are presently the only files generated by mesa:host. I have put the *.xzexe in https://github.com/heitbaum/mesa-host to this the POC further.

-rw-r--r-- 1 docker ubuntu  95711104 May  9 20:18 libclang-cpp.so.19.1
-rw-r--r-- 1 docker ubuntu  19603184 May  9 20:18 libclang-cpp.so.19.1.xz
-rw-r--r-- 1 docker ubuntu 103438152 May  9 20:00 libLLVM.so.19.1
-rw-r--r-- 1 docker ubuntu  26374492 May  9 20:00 libLLVM.so.19.1.xz
-rwxr-xr-x 1 docker ubuntu 155375080 May 10 06:19 mesa_clc
-rwxr-xr-x 1 docker ubuntu  54426713 May 10 06:31 mesa_clc.gzexe
-rwxr-xr-x 1 docker ubuntu  10805424 May 10 06:41 mesa_clc.shared-llvm
-rwxr-xr-x 1 docker ubuntu   2171836 May 10 06:41 mesa_clc.shared-llvm.xz
-rwxr-xr-x 1 docker ubuntu  36518736 May 10 06:19 mesa_clc.xz
-rwxr-xr-x 1 docker ubuntu  36519479 May 10 06:39 mesa_clc.xzexe
-rwxr-xr-x 1 docker ubuntu   9778192 May  9 20:22 panfrost_compile
-rwxr-xr-x 1 docker ubuntu   1725816 May 10 06:31 panfrost_compile.gzexe
-rwxr-xr-x 1 docker ubuntu   1306436 May  9 20:22 panfrost_compile.xz
-rwxr-xr-x 1 docker ubuntu   1307179 May 10 06:39 panfrost_compile.xzexe
-rwxr-xr-x 1 docker ubuntu   8225504 May  9 20:21 vtn_bindgen2
-rwxr-xr-x 1 docker ubuntu   1210581 May 10 06:31 vtn_bindgen2.gzexe
-rwxr-xr-x 1 docker ubuntu    911472 May  9 20:21 vtn_bindgen2.xz
-rwxr-xr-x 1 docker ubuntu    912215 May 10 06:39 vtn_bindgen2.xzexe
-rwxr-xr-x 1 docker ubuntu      5848 May 10 06:33 xzexe

[antonlacon]

What if tools arent available - self build?

My thought is yes, with an optional flag that can go into .libreelec/options that can force an error on download failure instead. Maybe same flag to select whether it's built or downloaded to begin with.

I'm guessing $MACHINE_HARDWARE_NAME won't be specific enough and the mesa package.mk needs to override HOST_CFLAGS at some point as builds default to march=native.