# Chez for architectures without native backends

**URL:** <https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950>\
**Category:** Distro Packagers\
**Tags:** question, chez\
**Created:** [May 1, 2022, 8:11pm UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950 "2022-05-01T20:11:50Z")\
**Posts on this page:** 10\
**Page:** 2

<div class="post-metadata">

**Author:** ![LiberalArtist](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/liberalartist/32/151_2.png) [@LiberalArtist](https://racket.discourse.group/u/LiberalArtist)\
**Post date:** [August 11, 2022, 4:05am UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/21 "2022-08-11T04:05:51Z")

</div>

A Guix user, Thiago Bauermann, [reported](https://issues.guix.gnu.org/57050#19) a problem bootstrapping with "rktboot" on powerpc64le-linux:

> I tried building the zuo branch from your gitlab repo (commit  
> 00975c823227 “gnu: chez-scheme-for-racket: Suport all systems.” from  
> August 8th) on powerpc64le-linux and had this build failure in  
> chez-scheme-for-racket-bootstrap-bootfiles-9.5.9.2:
> 
> ```scheme
> starting phase `build'
> Assuming current directory has Chez Scheme sources
> Use /tmp/guix-build-chez-scheme-for-racket-bootstrap-bootfiles-9.5.9.2.drv-0/source/racket/src/ChezScheme/rktboot/.
> Use /tmp/guix-build-chez-scheme-for-racket-bootstrap-bootfiles-9.5.9.2.drv-0/source/racket/src/ChezScheme/nanopass
> Use /tmp/guix-build-chez-scheme-for-racket-bootstrap-bootfiles-9.5.9.2.drv-0/source/racket/src/ChezScheme/s
> Check /tmp/guix-build-chez-scheme-for-racket-bootstrap-bootfiles-9.5.9.2.drv-0/source/racket/src/ChezScheme/boot/tpb64l
> Load nanopass
> Apply nanopass patch
> Load cmacros parts
> Load enum
> Load cprep
> Load expander
> Install evaluator
> Load cmacros using expander
> Continue loading expander
> Initialize system libraries
> Load nanopass using expander
> Load priminfo and primvars
> Load expander using expander
> Initialize system libraries in bootstrapped expander
> Declare nanopass in bootstrapped expander
> Load some io.ss declarations
> Load some strip.ss declarations
> Load some 7.ss declarations
> Load most front.ss declarations
> Define $filter-foreign-type
> Load mkheader
> Generate headers
> Load mkgc
> Generate GC
> Load ftype.ss
> Load fasl.ss
> Load reloc.ss
> Load format.ss
> Load cp0.ss
> Load cpvalid.ss
> Load cpcheck.ss
> Load cpletrec.ss
> Load cpcommonize.ss
> Load cpnanopass.ss
> error: in phase 'build': uncaught exception:
> %exception #<&invoke-error program: "/gnu/store/f72x3mdyagp67ybwdy9cqqsid9v8jk9l-racket-vm-bc-8.6/opt/racket-vm/bin/racket" arguments: ("rktboot/main.rkt" "--machine" "tpb64l") exit-status: 1 term-signal: #f stop-signal: #f> 
> phase `build' failed after 707.9 seconds
> command "/gnu/store/f72x3mdyagp67ybwdy9cqqsid9v8jk9l-racket-vm-bc-8.6/opt/racket-vm/bin/racket" "rktboot/main.rkt" "--machine" "tpb64l" failed with status 1
> 
> ```
> 
> I didn't have the chance yet to dig into why rktboot/main.rkt is  
> failing. If you have any tips on how to find more details on what is  
> going on (e.g., is there some verbose flag that can be passed to it?) I  
> can try to investigate.

I've confirmed that `racket rktboot/main.rkt --machine tpb64l` works for me (on x86\_64-linux) both on the v8.6 tag and on current master, so I'm not sure what else to try. I did give them instructions for testing this outside of the Guix build environment, and I pointed them to this thread.

---

<div class="post-metadata">

**Author:** ![mflatt](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/mflatt/32/6_2.png) [@mflatt](https://racket.discourse.group/u/mflatt)\
**Post date:** [August 11, 2022, 7:19am UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/22 "2022-08-11T07:19:46Z")

</div>

The problem with Racket BC on ppc64le seems to be in stack-overflow handling. I was able to get rktboot to complete by configuring the BC build with `CPPFLAGS=-DSTACK_SAFETY_MARGIN=200000`, but I don't know whether that's a complete or general solution.

---

<div class="post-metadata">

**Author:** ![LiberalArtist](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/liberalartist/32/151_2.png) [@LiberalArtist](https://racket.discourse.group/u/LiberalArtist)\
**Post date:** [August 11, 2022, 10:41am UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/23 "2022-08-11T10:41:17Z")

</div>

Thanks! I've adjusted my Guix package definition, and I'll ask Thiago to give it a try. This sounds like it may also explain my issue when I tried QEMU:

> [@LiberalArtist](#):
>
> I've also tried building emulating powerpc64le-linux-gnu again (as opposed to cross-compiling), and it fails when trying to run `rktboot` with Racket BC:  
> […]

so I'll try that again, too.

(Once the update to Racket 8.6 is merged, Guix's build farm will also test ppc64le.)

---

<div class="post-metadata">

**Author:** ![LiberalArtist](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/liberalartist/32/151_2.png) [@LiberalArtist](https://racket.discourse.group/u/LiberalArtist)\
**Post date:** [August 13, 2022, 4:45pm UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/24 "2022-08-13T16:45:28Z")

</div>

I haven't heard back from anyone with actual hardware yet, but QEMU failed for me the same way as before both with `CPPFLAGS=-DSTACK_SAFETY_MARGIN=200000` and, as an experiment, 10 times that. Of course, it could be that the issue under `qemu-user-static` is actually something different.

---

<div class="post-metadata">

**Author:** ![LiberalArtist](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/liberalartist/32/151_2.png) [@LiberalArtist](https://racket.discourse.group/u/LiberalArtist)\
**Post date:** [August 13, 2022, 10:50pm UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/25 "2022-08-13T22:50:19Z")

</div>

Thiago says that adding `-DSTACK_SAFETY_MARGIN=200000` for BC did get rktboot working on ppc64le and apparently the Chez Scheme build succeeded. However, minimal Racket CS failed during `make install` by trying to do a `raco setup` using the BC Racket that had been supplied to `--enable-racket=`, but incorrectly passing it `--cross-compiler`. Here's part of the log:

```scheme
starting phase `install'
/gnu/store/i9h1vc67h9148xvn8djk8j3smlkhaf09-zuo-1.0-racket8.6/bin/zuo . install DESTDIR=""
cp cs/c/racketcs /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/bin/racket
: /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/bin/racket
cp ../src/start/starter-sh /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/starter-sh
cp cs/c/starter /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/starter
: /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/starter
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -O info'@'compiler/cm -l- setup --chain ../src/setup-go.rkt cs/c/compiled ignored cs/c/ignored.d ../src/start/collects-path.rkt ../src/ /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/starter ../collects ../etc
compiler/cm: start-compile: /tmp/guix-build-racket-vm-cs-8.6.drv-0/source/racket/src/start/collects-path.rkt
compiler/cm: finish-compile: /tmp/guix-build-racket-vm-cs-8.6.drv-0/source/racket/src/start/collects-path.rkt
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -O info'@'compiler/cm -l- setup --chain ../src/setup-go.rkt cs/c/compiled ignored cs/c/ignored.d ../src/cs/c/gen-system.rkt /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/system.rktd tpb64l tpb64l machine ../src/cs/c/ ""
compiler/cm: start-compile: /tmp/guix-build-racket-vm-cs-8.6.drv-0/source/racket/src/cs/c/gen-system.rkt
compiler/cm: finish-compile: /tmp/guix-build-racket-vm-cs-8.6.drv-0/source/racket/src/cs/c/gen-system.rkt
cp ../src/cs/c/api.h /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/include/racketcs.h
cp ../src/cs/c/boot.h /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/include/racketcsboot.h
cp cs/c/ChezScheme/tpb64l/boot/tpb64l/scheme.h /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/include/chezscheme.h
cd cs/c/repack && ar x ../rktio/librktio.a
cd cs/c/repack && ar x ../ChezScheme/tpb64l/boot/tpb64l/libkernel.a
ar rc cs/c/libracketcs.a cs/c/repack/expeditor.o cs/c/repack/schsig.o cs/c/repack/compress-io.o cs/c/repack/rktio_flock.o cs/c/repack/gc-par.o cs/c/repack/rktio_shellex.o cs/c/repack/flushcache.o cs/c/repack/new-io.o cs/c/repack/rktio_signal.o cs/c/repack/print.o cs/c/repack/rktio_fd.o cs/c/repack/symbol.o cs/c/repack/rktio_poll_set.o cs/c/repack/schlib.o cs/c/repack/rktio_fs.o cs/c/repack/scheme.o cs/c/repack/rktio_wide.o cs/c/repack/rktio_main.o cs/c/repack/rktio_dll.o cs/c/repack/prim.o cs/c/repack/gc-oce.o cs/c/repack/fasl.o cs/c/repack/ffi.o cs/c/repack/segment.o cs/c/repack/rktio_convert.o cs/c/repack/rktio_error.o cs/c/repack/thread.o cs/c/repack/number.o cs/c/repack/rktio_process.o cs/c/repack/gc-ocd.o cs/c/repack/gc-011.o cs/c/repack/rktio_sha1.o cs/c/repack/rktio_network.o cs/c/repack/rktio_file.o cs/c/repack/random.o cs/c/repack/prim5.o cs/c/repack/io.o cs/c/repack/rktio_syslog.o cs/c/repack/rktio_hash.o cs/c/repack/vfasl.o cs/c/repack/rktio_console.o cs/c/repack/intern.o cs/c/repack/rktio_pipe.o cs/c/repack/rktio_sleep.o cs/c/repack/gcwrapper.o cs/c/repack/stats.o cs/c/repack/rktio_fs_change.o cs/c/repack/rktio_envvars.o cs/c/repack/rktio_ltps.o cs/c/repack/statics.o cs/c/repack/rktio_sha2.o cs/c/repack/foreign.o cs/c/repack/pb.o cs/c/repack/alloc.o cs/c/repack/rktio_time.o cs/c/repack/rktio_cpu.o cs/c/boot.o
cp cs/c/libracketcs.a /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/libracketcs.a
: /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/libracketcs.a
cp cs/c/gracketcs /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/gracket
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -O info'@'compiler/cm -l- setup --chain ../src/setup-go.rkt cs/c/compiled ignored cs/c/ignored.d ../src/start/collects-path.rkt ../src/ /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/bin/racket ../collects ../etc
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -O info'@'compiler/cm -l- setup --chain ../src/setup-go.rkt cs/c/compiled ignored cs/c/ignored.d ../src/start/collects-path.rkt ../src/ /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/gracket ../collects ../etc
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -O info'@'compiler/cm -l- setup --chain ../src/setup-go.rkt cs/c/compiled ignored cs/c/ignored.d ../src/cs/c/add-terminator.rkt cs/c/petite-v.boot /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/petite.boot
compiler/cm: start-compile: /tmp/guix-build-racket-vm-cs-8.6.drv-0/source/racket/src/cs/c/add-terminator.rkt
compiler/cm: finish-compile: /tmp/guix-build-racket-vm-cs-8.6.drv-0/source/racket/src/cs/c/add-terminator.rkt
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -O info'@'compiler/cm -l- setup --chain ../src/setup-go.rkt cs/c/compiled ignored cs/c/ignored.d ../src/cs/c/add-terminator.rkt cs/c/scheme-v.boot /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/scheme.boot
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -O info'@'compiler/cm -l- setup --chain ../src/setup-go.rkt cs/c/compiled ignored cs/c/ignored.d ../src/cs/c/add-terminator.rkt cs/c/racket-v.boot /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib/racket.boot
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -O info'@'compiler/cm -l- setup --chain ../src/setup-go.rkt cs/c/compiled ignored cs/c/ignored.d ../collects/setup/unixstyle-install.rkt make-install-copytree ../ /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/bin /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/collects /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/share/pkgs /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/doc /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/include /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/lib /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/share /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/etc /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/share/applications /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/man yes
compiler/cm: start-compile: /tmp/guix-build-racket-vm-cs-8.6.drv-0/source/racket/collects/setup/unixstyle-install.rkt
compiler/cm: finish-compile: /tmp/guix-build-racket-vm-cs-8.6.drv-0/source/racket/collects/setup/unixstyle-install.rkt
Copying collects -> /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/collects
Copying share/pkgs -> /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/share/pkgs
  missing source path "share/pkgs", skipping...
Copying share -> /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/share
  missing source path "share", skipping...
Copying doc -> /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/doc
  missing source path "doc", skipping...
Copying etc -> /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/etc
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket -MCR cs/c/compiled: --cross-compiler tpb64l cs/c -X /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/collects -G /gnu/store/cb84hlf8gb0nspc8f6n7qhihsflj7k6x-racket-vm-cs-8.6/opt/racket-vm/etc -N raco -l- setup --no-user
/gnu/store/w675i4y454bgcyr69fp672h51p24l1fg-racket-vm-bc-8.6/opt/racket-vm/bin/racket: bad switch: --cross-compiler
Use the --help or -h flag for help.
failed
 in build-one
 in loop
 in module->hash
make: *** [Makefile:16: install] Error 1
error: in phase 'install': uncaught exception:
%exception #<&invoke-error program: "make" arguments: ("install" "ZUO=/gnu/store/i9h1vc67h9148xvn8djk8j3smlkhaf09-zuo-1.0-racket8.6/bin/zuo") exit-status: 2 term-signal: #f stop-signal: #f> 
phase `install' failed after 26.8 seconds
command "make" "install" "ZUO=/gnu/store/i9h1vc67h9148xvn8djk8j3smlkhaf09-zuo-1.0-racket8.6/bin/zuo" failed with status 2

```

---

<div class="post-metadata">

**Author:** ![LiberalArtist](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/liberalartist/32/151_2.png) [@LiberalArtist](https://racket.discourse.group/u/LiberalArtist)\
**Post date:** [August 13, 2022, 11:16pm UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/26 "2022-08-13T23:16:21Z")

</div>

It looks like the problem might be the assumption in [https://github.com/racket/racket/blob/ab6dc20f78ff4e75655f245e28de44fa62a4b82d/racket/src/cs/c/configure.ac#L447-L456](https://github.com/racket/racket/blob/ab6dc20f78ff4e75655f245e28de44fa62a4b82d/racket/src/cs/c/configure.ac#L447-L456):

```scheme
# For a pb build where Racket is supplied, force cross-build
# mode on the assumption that the host is not a pb build
# (because it should be created with default configure options)
if test "${enable_pb}" = "yes" ; then
  if test "${enable_racket}" != "" ; then
    if test "${enable_target}" = "" ; then
      enable_target="${MACH}"
    fi
  fi
fi

```

---

<div class="post-metadata">

**Author:** ![mflatt](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/mflatt/32/6_2.png) [@mflatt](https://racket.discourse.group/u/mflatt)\
**Post date:** [August 13, 2022, 11:35pm UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/27 "2022-08-13T23:35:03Z")

</div>

Maybe that check should move before the preceding block that sets `MACH`, an then add check here that `"${MACH}" = ""`?

---

<div class="post-metadata">

**Author:** ![LiberalArtist](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/liberalartist/32/151_2.png) [@LiberalArtist](https://racket.discourse.group/u/LiberalArtist)\
**Post date:** [August 15, 2022, 7:30am UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/28 "2022-08-15T07:30:43Z")

</div>

> [@mflatt](#):
>
> Maybe that check should move before the preceding block that sets `MACH`, an then add check here that `"${MACH}" = ""`?

I thought this seemed right, but, when I started looking at changing the code, I was less sure. If the check I pointed to:

> [@LiberalArtist](#):
>
> ```scheme
> # For a pb build where Racket is supplied, force cross-build
> # mode on the assumption that the host is not a pb build
> # (because it should be created with default configure options)
> if test "${enable_pb}" = "yes" ; then
> if test "${enable_racket}" != "" ; then
> if test "${enable_target}" = "" ; then
> enable_target="${MACH}"
> fi
> fi
> fi
> 
> ```

moved before the preceding block beginning with `if test "${enable_mach}" != ""`, I think the result would be the same, because the preceding `case "$MACH_HOST_CPU"` statement sets `MACH=""` for `powerpc64*`, and the value from `--enable-mach=tpb64l` won't have been consulted yet.

* * *

Tangentially, I think:

```scheme
  powerpc64*)
    MACH=""
    pb_machine_name="${thread_prefix}pb64b"
    # MACH="${thread_prefix}ppc64${MACH_OS}"
    ;;

```

is wrong. POWER8 and POWER9 chips can be run in either big-endian or little-endian mode: `config.sub` normalizes them as e.g. `powerpc64-unknown-linux-gnu` and `powerpc64le-unknown-linux-gnu`. IIUC, this is set in the firmware or something: a given operating system runs in big-endian or little-endian mode, not both, so Debian has ports for both [`ppc64`](https://wiki.debian.org/PPC64) (big-endian) and [`ppc64el`](https://wiki.debian.org/ppc64el) (little-endian). (Guix only supports little-endian mode.)

More generally, I think it would be better to use the standard Autoconf macros `AC_C_BIGENDIAN` and `AC_CHECK_SIZEOF` rather than having to explicitly recognize architecture and os names.

* * *

As I looked around more, it seems there's a related assumption in this block slightly later in the file:

```scheme
if test "${enable_racket}" != "" ; then
  if test "${enable_racket}" != "auto" ; then
    SETUP_BOOT_MODE=--chain
  fi
  # In non-cross mode, we interpret `--enable-racket` to supply a
  # Racket used only for generating Chez Scheme boot files
  if test "${CROSS_MODE}" = "cross" ; then
    RACKET="${enable_racket}"
  elif test "${enable_racket}" != "auto" ; then
    BOOTFILE_RACKET="${enable_racket}"
  fi
fi

```

Until now, Guix has been `configure`ing our `racket-vm-cs` package with both `--enable-racket` and `--enable-scheme`. The intention was that the provided `scheme` would be used to generate the bootfiles and `racket` (CS when cross-compiling, 3M otherwise) would be used for other purposes: in particular, because Guix policy takes an especially firm stance on bootstrapping, we want to be able to schemify the `regexp`, `io`, and `thread` layers. However, it seems we were not actually doing that yet, so, as I workaround, I tried not providing `--enable-racket` for non-cross builds: it didn't break existing builds, and I've asked Thiago to try it on hardware.

For a different approach, could we just delete this block?

> [@LiberalArtist](#):
>
> ```scheme
> # For a pb build where Racket is supplied, force cross-build
> # mode on the assumption that the host is not a pb build
> # (because it should be created with default configure options)
> if test "${enable_pb}" = "yes" ; then
> if test "${enable_racket}" != "" ; then
> if test "${enable_target}" = "" ; then
> enable_target="${MACH}"
> fi
> fi
> fi
> 
> ```

If I'm following correctly, it seems like it's meant to handle a "cross" build for the current system, but for a pb or pbarch machine type: is there another way to handle that case?

---

<div class="post-metadata">

**Author:** ![mflatt](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/mflatt/32/6_2.png) [@mflatt](https://racket.discourse.group/u/mflatt)\
**Post date:** [August 15, 2022, 8:11am UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/29 "2022-08-15T08:11:10Z")

</div>

For now, I pushed a change that I think fixes the immediate problem. I'd rather not just delete the troublesome block, because its there to help with building pb much more quickly on a machine where a native build is supported.

I agree that using `AC_C_BIGENDIAN` and `AC_CHECK_SIZEOF` would be better.

---

<div class="post-metadata">

**Author:** ![LiberalArtist](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/liberalartist/32/151_2.png) [@LiberalArtist](https://racket.discourse.group/u/LiberalArtist)\
**Post date:** [August 21, 2022, 9:04pm UTC](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950/30 "2022-08-21T21:04:48Z")

</div>

> [@mflatt](#):
>
> For now, I pushed a change that I think fixes the immediate problem.

Thiago tried building with a cherry-picked 70e484e885637c495be5481983dae2207fdd67bb and reports that:

> For some reason I didn't understand, the problem I first reported  
> about rktboot/main.rkt failing during the build of  
> chez-scheme-for-racket-bootstrap-bootfiles came back. I had to increase  
> STACK\_SAFETY\_MARGIN again. I simply increased it 10x to make sure it  
> would work. If you want I can experiment with different values to find  
> an appropriate one.

So, as you suggested in:

> [@mflatt](#):
>
> The problem with Racket BC on ppc64le seems to be in stack-overflow handling. I was able to get rktboot to complete by configuring the BC build with `CPPFLAGS=-DSTACK_SAFETY_MARGIN=200000`, but I don't know whether that's a complete or general solution.

it seems like there's still some underlying problem. I don't think I know enough about BC internals to have any useful ideas.

For now, unless you have a better idea, I'll propose using the 10x larger `STACK_SAFETY_MARGIN` for Guix and hope that works well enough to bootstrap CS. Whatever the problem with BC on ppc64le is, I expect it would also be triggered by other Racket programs, so Guix using CS by default on all platforms still seems like an improvement.

[Previous page](https://racket.discourse.group/t/chez-for-architectures-without-native-backends/950.md?page=1)