Via @ydesgagn - he reports that it's possible to get flang working for iOS by running it through a Docker container.

Use this docker file to prepare a flang image:

FROM ubuntu:jammy

# persistent dependencies
RUN set -eux ; \
    apt-get -y update ; \
    apt-get -y --no-install-recommends install ca-certificates build-essential wget libncurses5 ;

# flang
RUN wget https://github.com/flang-compiler/flang/releases/download/flang_20190329/flang-20190329-x86-70.tgz ; \
    tar -xvzf *.tgz ; \
    rm -f *.tgz ; \
    ldconfig ;

Then, use this script (flang.sh) to execute the container:

#!/usr/bin/env bash

# shellcheck disable=SC2068
docker exec -it flang /root/host/proxy.sh "${PWD}" ${@}
cp -rf inbox/* "${PWD}" &> /dev/null
rm -rf inbox/* &> /dev/null

The replacement gfortran is a Python script that fixes command line arguments and calls flang.sh:

Details

#!/usr/bin/env python3

import sys
import os
import shlex
import subprocess
import string
import random
import shutil

def join_args(args):
    return ' '.join(shlex.quote(x) for x in args)

if "-dumpversion" in sys.argv:
    print("10.2.0")
    sys.exit(0)

arguments = []
sys_args = sys.argv
del sys_args[0]

try:
    for arg in os.environ["ARCHFLAGS"].split(" "):
        sys_args.append(arg)
except KeyError:
    pass

if "-h" in sys_args or "--help" in sys_args:
    print("The running executable emulates a Fortran compiler. If '-arch arm64' is passed, the compiler will produce an arm64 object file for iOS from the passed source. If not, gfortran located in '/opt/homebrew/bin/' will be executed.")
    print("Because flang runs in a Docker container, only files under '/Users/', '/var/folders' or '/Library' can be compiled.")
    sys.exit(0)

all_args_are_object_files = True

for arg in sys_args:

    if os.path.isfile(arg) and not arg.endswith(".o"):
        all_args_are_object_files = False

if (not "-c" and not all_args_are_object_files) in sys_args or not "-arch arm64" in " ".join(sys_args):
    print("The executed Fortran compiler only supports producing object files for iOS arm64, falling back to gfortran.", file=sys.stderr)
    print("To compile sources for iOS arm64, make sure to add -arch arm64 and -c.", file=sys.stderr)
    sys.exit(os.system(shlex.join(["/opt/homebrew/bin/gfortran"]+sys_args)))

if "-bundle" in sys_args or all_args_are_object_files:
    args = ["clang", "-undefined", "dynamic_lookup", "-shared"]
    try:
        for arg in os.environ["LDFLAGS"].split(" "):
            args.append(arg)
    except KeyError:
        pass
    for arg in sys_args:
        if arg != "-bundle":
            args.append(arg)
    
    command = shlex.join(args)
    sys.exit(os.system(command))

def convert_to_docker_path(arg):
    if arg.startswith("/"):
        arg = "/¡"+arg
    else:
        arg = os.path.join(os.getcwd(), arg)
    
    return arg

the_previous_parameter_was_dash_o = False
the_previous_parameter_was_dash_c = False
the_previous_parameter_was_dash_arch = False
output_path = None
source = None

for arg in sys_args:

    if arg == "-c":
        the_previous_parameter_was_dash_c = True
    elif the_previous_parameter_was_dash_c:
        the_previous_parameter_was_dash_c = False
        source = arg

    if arg == "-o":
        the_previous_parameter_was_dash_o = True
        continue
    elif the_previous_parameter_was_dash_o:
        the_previous_parameter_was_dash_o = False
        output_path = arg
        continue

    if arg == "-arch":
        the_previous_parameter_was_dash_arch = True
        continue
    elif the_previous_parameter_was_dash_arch:
        the_previous_parameter_was_dash_arch = False
        continue

    if arg == "-fallow-argument-mismatch":
        continue

    if os.path.exists(arg):
        arg = convert_to_docker_path(arg)
    if arg.startswith("-I"):
        path = arg.split("-I")[-1]
        arg = "-I"+convert_to_docker_path(path)

    if arg.startswith("/¡"):
        arg = arg[2:]

    arguments.append(arg)

if output_path is None and source is not None:
    parts = source.split(".")
    del parts[-1]
    output_path = os.getcwd()+"/"+".".join(parts)+".o"

if os.path.isfile(output_path):
    sys.exit(0)

print(output_path)

dir = os.path.dirname(os.path.abspath(__file__))
cwd = os.getcwd()

arguments.insert(0, os.path.abspath(os.path.join(dir, "flang.sh")))
arguments.insert(1, "--save-temps")
flang_command = join_args(arguments)

inbox = os.path.join(cwd, ".inbox"+''.join(random.choice(string.ascii_uppercase + string.digits) for _ in range(5)))

try:
    os.mkdir(inbox)
except FileExistsError:
    pass

os.chdir(inbox)

os.system(flang_command)
file_path = None

for file in os.listdir("."):
    if not file.endswith(".ll"):
        try:
            os.remove(file)
        except FileNotFoundError:
            pass
    else:
        file_path = os.path.join(os.getcwd(), file)

os.chdir(cwd)
llc = [os.path.join(dir, "llc"), "-mtriple=arm64-apple-ios", "-filetype=obj", file_path, "-o", output_path]
subprocess.run(llc, stdout=None, stderr=None)

shutil.rmtree(inbox)

The proxy.sh that is referenced is:

#!/usr/bin/env bash

cd /root/host || exit
cd "${1}" || exit
flang "${@:2}"

Uh oh!

Scipy #10

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What is the PyPI name of the package you would like to see added?

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