[bug#49565] [PATCH core-updates v2] gnu: bootstrap: Use %current-target-system to decide bootstrap path

[Thiago Jung Bauermann via Guix-patches via <guix-patches@gnu.org>]

Hello,

Em segunda-feira, 19 de julho de 2021, às 21:01:33 -03,
Thiago Jung Bauermann escreveu:
> Before the patch, these are the derivations that Guix tries to build when
> cross-compiling gcc-toolchain@11. Note the ‘mesboot’ packages:

One thing I forgot to mention, and which significance only dawned on me
later: there was a change in Guix behavior between versions of core-updates
since I posted v1 of this patch.

Before, I was getting a Guix exception during the build of glibc-mesboot,
as detailed in the first message in this issue. Now, the mesboot packages
build fine and the command below goes all the way to the gcc-11 package
just like when this patch is applied.

> --8<---------------cut here---------------start------------->8---
> $ ./pre-inst-env guix build --target=powerpc64le-linux-gnu gcc-toolchain@11
> substitute: atualizando substitutos de "https://ci.guix.gnu.org"... 100.0% 
> substitute: atualizando substitutos de "https://bordeaux.guix.gnu.org"... 100.0%
> The following derivations will be built:
> /gnu/store/3hrzq7fxj0cxgxkjybki2yi7dj70sgg8-gcc-toolchain-11.1.0.drv
> /gnu/store/2xpiffvzzizrjx48ghqac3rgh1cnljv7-linux-libre-headers-5.10.35.drv
> /gnu/store/4xlm78m6wl56gn4gpifvy8721amhi81j-binutils-2.36.1.drv
> /gnu/store/05lnycy4lmn0768r41sgikg795zk9mqg-binutils-cross-boot0-2.36.1.drv
> /gnu/store/1q62fcaj2gc9mnwvv6cicch6gc7qrnp0-binutils-mesboot-2.20.1a.drv
> /gnu/store/1yjrfb846y1mnc7mgab38jbv7pv0hgbh-tar-boot0-1.34.drv
> /gnu/store/9c7a2p899ivz16636prf44q0q61i4376-patch-mesboot-2.5.9.drv
> /gnu/store/9rmnv55i966wfkx0di4h6p8197hy2836-grep-mesboot-2.0.drv
> /gnu/store/advn8cgpcf9fi6424l8bs16r5mvfqs04-gcc-mesboot-wrapper-4.9.4.drv
> /gnu/store/bpghw1m585q2wjc0z4in9w0hcpxgiidw-gzip-mesboot-1.2.4.drv
> /gnu/store/bx9lr1bg5491dc9i5p2b6zgsq0ahajxb-gcc-mesboot-4.9.4.drv
> /gnu/store/dfijxa9mnlymzmsl571qlxx0qc65kxzi-tar-mesboot-1.22.drv
> /gnu/store/hp2f5sw9d189p7z930b63wr8k3j9k6j0-coreutils-mesboot-8.32.drv
> /gnu/store/i584nxkb39n67vzq5r3yh6spqppzrj43-bzip2-mesboot-1.0.8.drv
> /gnu/store/j1accym68y6l8pxz8095jpkwgp3ciphi-gawk-mesboot-3.1.8.drv
> /gnu/store/jlwyxh3k6hvpmy60g0ygwnncq66kn590-gash-utils-boot-0.1.0.drv
> /gnu/store/9mxvccmf0b8fwq0k7lw0ndsdsbz9y8vn-gash-boot-0.2.0.drv
> /gnu/store/p43yklj8d615y68jhcvycg9i3k3bqj2g-xz-mesboot-5.0.0.drv
> /gnu/store/rxn5c166a6p0p3y2hlyk67f91a504kfa-make-mesboot-3.82.drv
> /gnu/store/sgwdni3iwwrb4ahsnwm43528fzr5csiv-sed-mesboot-4.0.6.drv
> /gnu/store/xxaccspqlg90v3cxrbvslva6s8gwxzi9-make-boot0-4.3.drv
> /gnu/store/zghmr1xyw5ip3wpi1qw2ysc7p6i75d54-glibc-mesboot-2.16.0.drv
> /gnu/store/64cway6pvw5fk7csym2k9i77rhp1pl46-coreutils-boot0-8.32.drv
> /gnu/store/7hvyky0i1hf3xbd698rr305br881pwz6-diffutils-boot0-3.7.drv
> /gnu/store/hq1lijdac3vqx811jzsg0wizsbgwgpaa-gawk-boot0-5.1.0.drv
> /gnu/store/i173n23qpssi7idck4jn7399bfkldlfs-sed-boot0-4.8.drv
> /gnu/store/l8kbhm6m9rbwkxn7zv1d06wbl2gi88wp-findutils-boot0-4.8.0.drv
> /gnu/store/pfq7g9jx16jlk3829312h88n0k1jnfns-patch-boot0-2.7.6.drv
> /gnu/store/qp3yg441ybh6bv44lrcxyp6rzyf0djii-file-boot0-5.39.drv
> /gnu/store/x4m7lff1ps5mas719815d54x6x1zwcv3-bzip2-boot0-1.0.8.drv
> /gnu/store/h5hwcnr7z57hb9b8bhhx7s22kfawqr0d-ld-wrapper-boot0-0.drv
> /gnu/store/v9p5fm974mj4d99vdpp9dhrvpwd4kfgs-glibc-2.33.drv
> /gnu/store/0kjyjcxzk5mv6zm86x8f18sbsb9m48k8-bash-static-5.1.8.drv
> /gnu/store/6h220skb9ak8ppv5417i8cbry1byv73a-glibc-intermediate-2.33.drv
> /gnu/store/rwczga96661d70jcqds8w8pr5s084mh4-gcc-cross-boot0-10.3.0.drv

Also, inspecting this gcc-cross-boot0 derivation, I see the following
derivations mentioned in it:

/gnu/store/034y7d9d36986pin4b5plx2ryda1h8i5-glibc-cross-powerpc64le-linux-gnu-2.33.drv
/gnu/store/0gihg5kfh4m09hmc45kwf7kjnv1m84gz-gcc-cross-powerpc64le-linux-gnu-10.3.0.drv
/gnu/store/4ld0jqb2q0di90nizv1vvfngnm39mhln-binutils-cross-powerpc64le-linux-gnu-2.36.1.drv
/gnu/store/m7ddjasnrl290002kql8szh7ahjvl2ir-linux-libre-headers-cross-powerpc64le-linux-gnu-5.10.35.drv

And looking at the gcc-11 build directory, I see:

```
$ find /tmp/guix-build-gcc-11.1.0.drv-0 -name '*.o' -exec file '{}' ';' | cut -d: -f2 | sort | uniq -c
      3  ELF 64-bit LSB relocatable, 64-bit PowerPC or cisco 7500, version 1 (GNU/Linux), with debug_info, not stripped
    235  ELF 64-bit LSB relocatable, 64-bit PowerPC or cisco 7500, version 1 (SYSV), not stripped
   1496  ELF 64-bit LSB relocatable, 64-bit PowerPC or cisco 7500, version 1 (SYSV), with debug_info, not stripped
    118  ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), not stripped
     14  ELF 64-bit LSB relocatable, x86-64, version 1 (SYSV), with debug_info, not stripped
```

Which is the exact same output I see with the failed gcc-11 build directory
when this patch is applied.

So now I wonder whether these mesboot derivations are just used to bootstrap
x86_64 packages which are then used to build the cross-toolchain, in which
case this patch isn’t actually necessary?

> /gnu/store/cglgsds6hxy9swdyymgam9l3rfwizyfr-libstdc++-boot0-4.9.4.drv
> /gnu/store/c63lqgh0x2rx1az0ds4b2ma9vgiry31j-gcc-11.1.0.drv
> /gnu/store/f4fwnxsha5h2pk750r2p09cnhbhc3nm3-ld-wrapper-0.drv
> /gnu/store/605p0jq8wv879n3y6fbqxvaiww1kjaql-libunistring-0.9.10.drv
> /gnu/store/5irbp0c5zzvs50wlznpfxcxr8mfndwy9-gcc-10.3.0.drv
> /gnu/store/byfbnlkwj9pjwnkx69fi2ycnqdvz2znv-ld-wrapper-boot3-0.drv
> /gnu/store/fbm3gv13nggw2qcvxmlccqgi0izzgdwn-libstdc++-10.3.0.drv
> /gnu/store/vhwmw9p8l3sysqlm8bh14xkfw1afqqcj-zlib-1.2.11.drv
> /gnu/store/60jiv5k1lg2krj3b0f9x7f26ywrda0mw-bash-minimal-5.1.8.drv
> /gnu/store/i0lk6zd2vwqqlhn8kkf0529x896lnzr1-guile-3.0.7.drv
> /gnu/store/r25wjwjbb13yk8yc4bm77dxxcq9qvx9y-libatomic-ops-7.6.10.drv
> /gnu/store/ry3zxxjsnhpdphvnnr991x9yk7gljxy9-libffi-3.3.drv
> /gnu/store/y26kx37mkidni8jj4sjn0ryy1wq1pqvs-libgc-8.0.4.drv
> /gnu/store/v9p5fm974mj4d99vdpp9dhrvpwd4kfgs-glibc-2.33.drv
> --8<---------------cut here---------------end--------------->8---

-- 
Thanks,
Thiago