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https://github.com/konimex/kiss-llvm

A kiss-repo structure to build standalone LLVM
https://github.com/konimex/kiss-llvm

kiss-repo

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A kiss-repo structure to build standalone LLVM

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README 

        
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|\ISS LINUX (unofficial repository)                https://kisslinux.org

________________________________________________________________________



This is a kiss-compliant repository structure to build LLVM without any

traces of GCC libraries. It also provides any alternatives for official

KISS packages that cannot be built in an LLVM-only environment as is.



This repository is to be used in conjunction with KISS Linux

repositories and NOT as a total replacement for KISS Linux.



DISCLAIMER

________________________________________________________________________



While since 11 July KISS does support an LLVM/Clang toolchain as a first

class citizen along with GCC [1] (some of our changes to accommodate

systems built with kiss-llvm toolchain are also accepted), some packages

(namely, eiwd) will not work with Clang at all at present (version 1.15,

at the time I'm writing this). Those packages will *explicitly* depend

on gcc (and any attempts to build gcc with this repo will automatically

fail unless user manually overrides that by using their own repo, or

directly building it, CRUX-style, note that I won't be supporting the

use case though since I don't think it is possible without significant

headache).



When submitting reports about failure to build LLVM/Clang from this

repo, report it here, not kisslinux/repo. Otherwise, you probably

can open an issue there, but please state your toolchain.



Building kiss-llvm

________________________________________________________________________



To build LLVM compiler infrastructure from scratch (and without any

traces of GCC), you'll need to build and install the llvm bootstrap

packaged as @llvm before building the main llvm package.



See the build file for @llvm for more information. It builds

llvm proper first, clang (pass 1), compiler-rt, libunwind, libc++abi,

libc++, and finally, clang again (pass 2).



NOTE: This is what I could do, however, if you can find a better way

      that doesn't require 2 passes to clang, patches welcome! Also,

      some required packages may be missing.



Recommended: Since downloading files repeatedly is a waste of bandwidth

             (especially if you have a slow Internet), you can use this

             command to symlink thesource cache (usually located in

             $HOME/.cache/kiss/sources):



$ ln -s llvm @llvm



And make sure to download the main LLVM package sources first and NOT

the bootstrap packages (by using `kiss c` in the llvm directory, or by

using `kiss c llvm` after adding the kiss-llvm directory to $PATH, make

sure the checksums are NOT changed, git should be able to track these).



Using LLVM from kiss-llvm

________________________________________________________________________



After installing llvm from kiss-llvm (and uninstalling the temporary

bootstrap packages), you can use the alternatives system to switch to

LLVM-provided binutils (except as).



Because programs might still detect GCC and use it, you can force Clang

by applying environment variables CC=cc and CXX=c++ after applying the

alternatives. (For some packages like Busybox, you may need to

explicitly use CC=clang, as they explicitly detect Clang through the

name of the binary)



Also, you will need to rebuild every single package that links to

/lib/libstdc++.so, a small way to check if a library or a program links

to libstdc++ using the shell as follows:



$ for file in /usr/bin/* /usr/lib/*; do

      echo FILE: "$file"       # This is as an identifier of which file

      ldd "$file" | grep libstdc++

  done



You may also need to check if any packages link to libatomic.so and

libgcc_s.so.



You can use kiss-owns to check which file belongs to which package, and

rebuild that.



________________________________________________________________________



If you think replacing just the compiler and the binutils is not enough,

head on over to Wyverkiss [2] since the distribution also removes the

need for GNU bison and many others (GNU make cannot be removed though).

Please note that Wyverkiss will _NOT_ be supported by Dylan though.



[1] https://kisslinux.org/blog/20210711a

[2] https://github.com/wyvertux/wyverkiss