Re: [yocto] Regression in rust-cross-canadian-aarch64

[Richard Purdie <richard.purdie@linuxfoundation.org>]

On Tue, 2022-06-28 at 11:00 +0200, Peter Bergin wrote:
> On 2022-06-19 22:47, Peter Bergin wrote:
> 
> 
> The reason for this issue seems to be this commit:
> 
>      commit 781eaa955dce5deab47371c25dae72b36c011900
>      Author: Richard Purdie <richard.purdie@linuxfoundation.org>
>      Date:   Sat May 21 14:02:47 2022 +0100
> 
>          rust-common: Drop LLVM_TARGET and simplify
> 
>          This all seems over complicated for something which is 
> basically always
>          one of two values. This might even help cross-canadian work on 
> something
>          which isn't x86-64.
> 
>          (From OE-Core rev: bd36593ba3db758b3eacc974e48468a665967961)
> 
>          Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> 
> 
> When building rust-cross-canadian-aarch64 the file 
> 'tmp/work/x86_64-nativesdk-pokysdk-linux/rust-cross-canadian-aarch64/1.60.0-r0/targets/aarch64-poky-linux.json' 
> will be populated with the information '"llvm-target": 
> "x86_64-unknown-linux-gnu"'. This will lead to object files in wrong 
> format during 'Building stage2 std artifacts (x86_64-unknown-linux-gnu 
> -> aarch64-poky-linux)' in the do_compile step.
> 
> In 'meta/recipes-devtools/rust/rust-common.inc':
> 
>      # build tspec
>      tspec = {}
>      if bb.data.inherits_class('cross-canadian', d):
>          tspec['llvm-target'] = d.getVar('RUST_HOST_SYS', arch_abi)
>      else:
>          tspec['llvm-target'] = d.getVar('RUST_TARGET_SYS', arch_abi)
> 
> So for some reason it seems intentional to set 'llvm-target' to HOST_SYS 
> when 'cross-canadian'. The behavior has changed with this patch. Before 
> 'llvm-target' was set to RUST_TARGET_SYS for all target archs other than 
> x86_64 where it was set to RUST_HOST_SYS. I guess this change has to do 
> with the commit message 'This might even help cross-canadian work on 
> something which isn't x86-64.'? But unfortunately it seems to break the 
> case building on x86_64 for aarch64. It would be good to get some help 
> here to sort this out.

I'm wondering if we need something like:

diff --git a/meta/recipes-devtools/rust/rust-common.inc b/meta/recipes-devtools/rust/rust-common.inc
index 621cd4ad576..ef70c48d0f4 100644
--- a/meta/recipes-devtools/rust/rust-common.inc
+++ b/meta/recipes-devtools/rust/rust-common.inc
@@ -309,10 +309,7 @@ def rust_gen_target(d, thing, wd, features, cpu, arch, abi=""):
 
     # build tspec
     tspec = {}
-    if bb.data.inherits_class('cross-canadian', d):
-        tspec['llvm-target'] = d.getVar('RUST_HOST_SYS', arch_abi)
-    else:
-        tspec['llvm-target'] = d.getVar('RUST_TARGET_SYS', arch_abi)
+    tspec['llvm-target'] = d.getVar('RUST_TARGET_SYS', arch_abi)
     tspec['data-layout'] = d.getVarFlag('DATA_LAYOUT', arch_abi)
     tspec['max-atomic-width'] = int(d.getVarFlag('MAX_ATOMIC_WIDTH', arch_abi))
     tspec['target-pointer-width'] = d.getVarFlag('TARGET_POINTER_WIDTH', arch_abi)


?

Cheers,

Richard