Subject: Re: [PATCH v3 12/14] gnu: chez-scheme-for-racket: Suport all systems.

From: Efraim Flashner <[email-masked]>
Date: Thu, 25 Aug 2022 13:50:05 +0300

On Thu, Aug 25, 2022 at 11:24:31AM +0200, Liliana Marie Prikler wrote:
> Should be "Support all systems".
> 
> Am Donnerstag, dem 25.08.2022 um 04:54 -0400 schrieb Philip McGrath:
> > On systems for which Racket's variant of Chez Scheme cannot generate
> > native code, it can use a 'pbarch' machine type: a variant of the
> > ``portable bytecode'' backend specialized to word size and endianness.
> > This allows Racket CS to replace Racket BC on those systems while
> > maintaining comparable performance. (Racket BC lacks JIT support for
> > those systems anyway.) It also lets us provide a Chez Scheme package on
> > all systems Guix supports.
> > 
> > This patch adds 'pbarch' support to both 'chez-scheme-for-racket' and
> > 'racket-vm-cs', but it does not change the Racket VM implementation
> > used
> > for the 'racket' and 'racket-minimal' packages.
> > 
> > * gnu/packages/chez.scm (nix-system->pbarch-machine-type): New
> > variable.
> > (chez-scheme-for-racket)[inputs]: Use 'libffi' for non-native systems.
> > [arguments]<#:configure-flags>: Always supply '-m='. Add applicable
> > flags for non-native systems.
> > [supported-systems]: Use '%supported-systems'.
> > [description]: Update.
> > (chez-scheme-for-racket-bootstrap-bootfiles)[arguments]<#:phases>:
> > Adapt
> > 'build' phase for non-native systems.
> > * gnu/packages/racket.scm (racket-vm-bc)[description]: Update.
> > (racket-vm-cs)[description]: Likewise.
> > [inputs]: Use 'libffi' for non-native systems.
> > [arguments]<#:configure-flags>: Add applicable flags for non-native
> > systems.
> > ---
> >  gnu/packages/chez.scm   | 76 ++++++++++++++++++++++++++++++-----------
> >  gnu/packages/racket.scm | 26 +++++++++-----
> >  2 files changed, 74 insertions(+), 28 deletions(-)
> > 
> > diff --git a/gnu/packages/chez.scm b/gnu/packages/chez.scm
> > index 26f653ea9d..5d152b3db5 100644
> > --- a/gnu/packages/chez.scm
> > +++ b/gnu/packages/chez.scm
> > @@ -37,6 +37,7 @@ (define-module (gnu packages chez)
> >    #:use-module (gnu packages compression)
> >    #:use-module (gnu packages ncurses)
> >    #:use-module (gnu packages ghostscript)
> > +  #:use-module (gnu packages libffi)
> >    #:use-module (gnu packages linux)
> >    #:use-module (gnu packages netpbm)
> >    #:use-module (gnu packages racket)
> > @@ -49,6 +50,7 @@ (define-module (gnu packages chez)
> >    #:use-module (srfi srfi-26)
> >    #:export (chez-scheme-for-system
> >              racket-cs-native-supported-system?
> > +            nix-system->pbarch-machine-type
> >              unpack-nanopass+stex))
> >  
> >  ;; Commentary:
> > @@ -231,6 +233,28 @@ (define* (chez-upstream-features-for-system
> > #:optional
> >      (and=> (assoc-ref %chez-features-table chez-os)
> >             (cut assoc-ref <> chez-arch))))
> >  
> > +(define* (nix-system->pbarch-machine-type #:optional
> > +                                          (system
> > +                                           (or (%current-target-
> > system)
> > +                                               (%current-system)))
> > +                                          #:key (threads? #t))
> > +  "Return a string naming the pseudo–machine type used by Racket's
> > variant of
> > +Chez Scheme to represent the appropriate ``pbarch'' backend for
> > SYSTEM: that
> > +is, the ``portable bytecode'' backend specialized for SYSTEM's word
> > size and
> > +endianness.  The result will name the threaded machine type unless
> > THREADS? is
> > +provided and is #f."
> > +  (string-append (if threads?
> > +                     "t"
> > +                     "")
> > +                 "pb"
> > +                 (if (target-64bit? system)
> > +                     "64"
> > +                     "32")
> > +                 ;; missing (guix utils) predicate target-little-
> > endian?
> > +                 (if (target-ppc32? system)
> > +                     "b"
> > +                     "l")))
> > +
> Don't we already have a function that does something similar?  Can't we
> add a #:portable-bytecode? keyword to that one?

I'm not aware of a function that checks for endianness. The only other
place I know of is (guix build-system meson), but there the logic is
hand-written.

> >  (define* (racket-cs-native-supported-system? #:optional
> >                                               (system
> >                                                (or (%current-target-
> > system)
> > @@ -449,10 +473,14 @@ (define-public chez-scheme-for-racket
> >      ;; When updating, remember to also update %racket-version in
> > racket.scm.
> >      (source #f) ; avoid problematic cycle with racket.scm
> >      (inputs
> > -     (modify-inputs (package-inputs chez-scheme)
> > -       (delete "libx11" "util-linux:lib")
> > -        (replace "chez-scheme-bootstrap-bootfiles"
> > -          chez-scheme-for-racket-bootstrap-bootfiles)))
> > +     (let ((inputs (modify-inputs (package-inputs chez-scheme)
> > +                     (replace "chez-scheme-bootstrap-bootfiles"
> > +                       chez-scheme-for-racket-bootstrap-bootfiles)
> > +                     (delete "libx11" "util-linux:lib"))))
> > +       (if (racket-cs-native-supported-system?)
> > +           inputs
> > +           (modify-inputs inputs
> > +             (prepend libffi)))))
> >      (native-inputs
> >       (let ((native-inputs (modify-inputs (package-native-inputs chez-
> > scheme)
> >                              (prepend zuo))))
> > @@ -473,10 +501,16 @@ (define-public chez-scheme-for-racket
> >         ((#:configure-flags cfg-flags #~'())
> >          #~`("--disable-x11"
> >              "--threads" ;; ok to potentially duplicate
> > -            #$@(if (%current-target-system)
> > -                   (list (string-append "-m="
> > -                                        (racket-cs-native-supported-
> > system?)))
> > -                   '())
> > +            #$(string-append "-m=" (or (racket-cs-native-supported-
> > system?)
> > +                                       (nix-system->pbarch-machine-
> > type)))
> > +            ;; ^ could skip -m= for non-cross non-pbarch builds
> > +            #$@(if (racket-cs-native-supported-system?)
> > +                   #~()
> > +                   ;; not inferred on non-native platforms: see
> > +                   ;; https://racket.discourse.group/t/950/9
> > +                   #~("--enable-libffi"
> > +                      "CFLAGS=-g -O2 -D_REENTRANT -pthread"
> > +                      "LIBS=-lm -ldl -lrt -lffi -lncurses"))
> >              #$@(if (%current-target-system)
> >                     (list (string-append "--toolprefix="
> >                                          (%current-target-system)
> > @@ -543,10 +577,7 @@ (define-public chez-scheme-for-racket
> >                (add-after 'unpack 'chdir
> >                  (lambda args
> >                    (chdir "racket/src/ChezScheme"))))))))
> > -    ;; TODO: How to build pbarch/pbchunks for other systems?
> > -    ;; See https://racket.discourse.group/t/950
> > -    (supported-systems (filter racket-cs-native-supported-system?
> > -                               %supported-systems))
> > +    (supported-systems %supported-systems)
> I don't think this needs to be specified, does it?
> 
> See the definition in guix/packages.scm:
>   (supported-systems package-supported-systems    ; list of strings
>                      (default %supported-systems))

Unless this package inherits from somewhere else then by default
supported-systems is all systems. (Regardless if all dependencies are
supported. To see more look at the difference between
(package-supported-systems "pandoc") and
(package-transitive-supported-systems "pandoc"))

-- 
Efraim Flashner   <[email-masked]>   אפרים פלשנר
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