Re: MIPS bootstrap problem in core-updates

[Ludovic Courtès]

Mark H Weaver <address@hidden> skribis:

> In core-updates, 'glibc-final-with-bootstrap-bash' fails to build on
> MIPS, because 'gcc-boot0' doesn't work.  The problem is that we've
> switched to gcc-4.9, which on MIPS now emits a new ".nan" assembler
> directive which is not understood by the assembler in binutils-2.23.2,
> the version in our binutils-bootstrap-0.
>
> The assembler in binutils-2.25 understands ".nan", and that version of
> binutils is an input to 'glibc-final-with-bootstrap-bash' (via
> %boot1-inputs), so one might expect this to work.  There's just one
> problem: the assembler in 'binutils-boot0' is named
> 'mips64el-guix-linux-gnu-as', but the compiler in 'gcc-boot0' runs 'as'.
>
> Historically, we've worked around this by including the bootstrap
> binutils in %boot1-inputs:
>
> (define %boot1-inputs
>   ;; 2nd stage inputs.
>   `(("gcc" ,gcc-boot0)
>     ("binutils-cross" ,binutils-boot0)
>
>     ;; Keep "binutils" here because the cross-gcc invokes `as', not the
>     ;; cross-`as'.
>     ,@%boot0-inputs))

Thanks for the detailed analysis!

This (lightly tested) patch may work:

diff --git a/gnu/packages/commencement.scm b/gnu/packages/commencement.scm
index ab16660..6dd4d55 100644
--- a/gnu/packages/commencement.scm
+++ b/gnu/packages/commencement.scm
@@ -139,6 +139,19 @@
      (arguments
       `(#:guile ,%bootstrap-guile
         #:implicit-inputs? #f
+
+        #:phases (alist-cons-after
+                  'install 'add-gas-symlink
+                  (lambda* (#:key outputs #:allow-other-keys)
+                    ;; The cross-gcc invokes 'as', not the cross-'as', so add
+                    ;; an 'as' symlink.
+                    (let ((out (assoc-ref outputs "out")))
+                      (with-directory-excursion (string-append out "/bin")
+                        (symlink (string-append ,(boot-triplet) "-as")
+                                 "as")
+                        #t)))
+                  %standard-phases)
+
         ,@(substitute-keyword-arguments (package-arguments binutils)
             ((#:configure-flags cf)
              `(cons ,(string-append "--target=" (boot-triplet))
@@ -274,10 +287,7 @@
   ;; 2nd stage inputs.
   `(("gcc" ,gcc-boot0)
     ("binutils-cross" ,binutils-boot0)
-
-    ;; Keep "binutils" here because the cross-gcc invokes `as', not the
-    ;; cross-`as'.
-    ,@%boot0-inputs))
+    ,@(alist-delete "binutils" %boot0-inputs)))
 
 (define glibc-final-with-bootstrap-bash
   ;; The final libc, "cross-built".  If everything went well, the resulting

Could you try it on MIPS, on top of ‘core-updates’?

It looks like the simplest solution.

Thanks,
Ludo’.