failure with exe generation, submodules, provide, define-syntax, and cross-compilation to arm32-linux

[samth]

[samth@hector:~/tmp/worksheets (main) ] [27s] cat /tmp/test.rkt
#lang racket
(define-syntax f 1)
(module+ for-testing (provide f))

[samth@hector:~/tmp/worksheets (main) ] [195s] raco cross --target arm32-linux exe -o /tmp/test-local /tmp/test.rkt
>> Cross configuration
 Target:    arm-linux
 Host:      x86_64-linux
 Version:   9.1
 VM:        cs
 Workspace: /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1
fasl-read: incompatible fasl-object machine-type 'tarm32le found in #<binary input port bytevector>
  context...:
   body of syntax-literals
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/syntax/private/modcode-noctc.rkt:139:0: get-module-code
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/compiler/embed.rkt:446:0: get-code
   [repeats 1 more time]
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/racket/private/map.rkt:267:2: gen-for-each
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/compiler/embed.rkt:1191:0: do-write-module-bundle
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/compiler/embed.rkt:1676:15: write-module
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/compiler/embed.rkt:1811:29
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/compiler/private/elf.rkt:289:0: expand-elf
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/compiler/embed.rkt:1580:6
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/share/pkgs/compiler-lib/compiler/commands/exe.rkt:100:0
   body of "/home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/share/pkgs/compiler-lib/compiler/commands/exe.rkt"
   /home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/raco/raco.rkt:41:0
   body of "/home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/raco/raco.rkt"
   body of "/home/samth/.rackup/addons/release-9.1-cs-x86_64-linux-full/raco-cross/9.1/arm-linux-cs/collects/raco/main.rkt"
raco cross: command failed

[samth]

This also fails on i386-linux for me.

[samth]

Here's a simpler reproduction, without raco cross:

;; trigger.rkt
#lang racket/base
(parameterize ([current-compile-target-machine 'tarm32le]
               [current-namespace (make-base-namespace)])
  (compile
   #'(module m '#%kernel
       (#%require (for-syntax '#%kernel))
       (define-syntaxes (f) 1)
       (module* for-testing #f))))

racket --cross-compiler tarm32le <xpatch-dir> trigger.rkt

where <xpatch-dir> is something like /home/samth/sw/plt/add-on/raco-cross/9.1/src-builtpkgs/lib/

[mflatt]

Using raco cross make succeeds for me, and then raco cross exe works with the cross-compiled files. The intent is that racro cross exe will work even without compilation — so, there's something to fix/improve here — but cross exe by itself has been difficult to get right, while make before exe is more reliable and generally faster/better.

Although the short program reports the same error, I'm not sure it's really the same problem, particularly since cross make works. Cross-compiling with dependencies (even submodules) is tricky, and parameters have to be set up just right. Or the short example might be something that can work, and maybe fixing that really does point to the exe repair.

[mflatt]

A raco make succeeds by compiling to platform-independent form, and then recompiling that to the target platform. I pushed a change to Racket (so the repair only works for future versions) that uses the same strategy for raco exe when cross-compiling.

To demonstrate in terms of the simpler example above, it can be adapted like this:

#lang racket/base
(parameterize ([current-namespace (make-base-namespace)])
  (define c
    (parameterize ([current-compile-target-machine #f])
      (compile
       #'(module m '#%kernel
           (#%require (for-syntax '#%kernel))
           (define-syntaxes (f) 1)
           (module* for-testing #f )))))
  (parameterize ([current-compile-target-machine 'ta6le])
    (compiled-expression-recompile c)))

[samth]

Thanks! Will this work just by using raco cross where the raco is from HEAD, or do I need the installed cross-toolchain to be updated. It was not obvious to me from the documentation how to use raco cross with HEAD as the target (rather than the host) racket.

[mflatt]

You can't really use a Git HEAD for this, but you can use a snapshot (tomorrow-ish) as described in https://docs.racket-lang.org/raco-cross/index.html#%28part._snapshots%29.

To check the change, I created a snapshot build using HEAD:

#lang distro-build/config
(require distro-build/main-distribution)

(sequential
 #:splice (make-spliceable-limits)
 #:pkgs '()
 #:site-dest "/tmp/snapshots/dist"
 (make-machines
  #:minimal? #t
  #:filter-rx #rx"Linux.*64-bit x86_64|Mac OS.*64-bit Apple Silicon|Source"
  #:natipkg? #f))

[samth]

Ok, that's basically what I figured based on the documentation.