Add new env2cross command.

pull/10095/head
Jussi Pakkanen 3 years ago
parent 789f440f7c
commit e257a870fe
  1. 40
      docs/markdown/snippets/env2cross.md
  2. 4
      mesonbuild/mesonmain.py
  3. 368
      mesonbuild/scripts/env2mfile.py

@ -0,0 +1,40 @@
## Experimental command to convert environments to cross files
Meson has a new command `env2mfile` that can be used to convert
"environment variable based" cross and native compilation environments
to Meson machine files. This is especially convenient for e.g. distro
packagers so they can easily generate unambiguous configuration files
for packge building.
As an example here's how you would generate a cross file that takes
its settings from the `CC`, `CXX`, `CFLAGS` etc environment variables.
meson env2mfile --cross --system=baremetal --cpu=armv7 --cpu-family=arm -o armcross.txt
The command also has support for generating Debian build files using
system introspection:
meson env2mfile --cross --debarch armhf -o debarmhf_cross.txt
Note how you don't need to specify any system details, the command
gets them transparently via `dpkg-architecture`.
Creating a native file is done in the same way:
meson env2mfile --native -o current_system.txt
This system will detect if the `_FOR_BUILD` environment variables are
enabled and then uses them as needed.
With this you should be able to convert any envvar-based cross build
setup to cross and native files and then use those. Thit means, among
other things, that you can then run your compilations from any shell,
not just the special one that has all the environment variables set.
As this functionality is still a bit in flux, the specific behaviour
and command line arguments to use are subject to change. Because of
this the main documentation has not yet been updated.
Please try this for your use cases and report to us if it is working.
Patches to make the autodetection work on other distros and platforms
are also welcome.

@ -30,7 +30,7 @@ from . import mconf, mdist, minit, minstall, mintro, msetup, mtest, rewriter, ms
from .mesonlib import MesonException, MesonBugException
from .environment import detect_msys2_arch
from .wrap import wraptool
from .scripts import env2mfile
# Note: when adding arguments, please also add them to the completion
# scripts in $MESONSRC/data/shell-completions/
@ -70,6 +70,8 @@ class CommandLineParser:
help_msg='Build the project')
self.add_command('devenv', mdevenv.add_arguments, mdevenv.run,
help_msg='Run commands in developer environment')
self.add_command('env2mfile', env2mfile.add_arguments, env2mfile.run,
help_msg='Convert current environment to a cross or native file')
# Hidden commands
self.add_command('runpython', self.add_runpython_arguments, self.run_runpython_command,

@ -0,0 +1,368 @@
# Copyright 2022 The Meson development team
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import sys, os, subprocess, shutil
import shlex
import argparse
from typing import TextIO, Dict, List, Union, Tuple, Any, Optional
from .. import mlog
UNIXY_ENVVARS_COMPILER = {'c': 'CC',
'cpp': 'CXX',
'objc': 'OBJCC',
'objcpp': 'OBJCXX',
'fortran': 'FC',
'rust': 'RUSTC',
'vala': 'VALAC',
'cs': 'CSC',
}
UNIXY_ENVVARS_TOOLS = {'ar': 'AR',
'strip': 'STRIP',
'windres': 'WINDRES',
'pkgconfig': 'PKG_CONFIG',
'vapigen': 'VAPIGEN',
'cmake': 'CMAKE',
'qmake': 'QMAKE',
}
UNIXY_ENVVARS_FLAGS = {'c': 'CFLAGS',
'cpp': 'CXXFLAGS',
'objc': 'OBJCFLAGS',
'objcpp': 'OBJCXXFLAGS',
'fortran': 'FFLAGS',
'rust': 'RUSTFLAGS',
'vala': 'VALAFLAGS',
'cs': 'CSFLAGS', # This one might not be standard.
}
TYPICAL_UNIXY_COMPILER_NAMES = {'c': ['cc', 'gcc', 'clang'],
'cpp': ['c++', 'g++', 'clang++'],
'objc': ['objc', 'clang'],
'objcpp': ['objcpp', 'clang++'],
'fortran': ['gfortran'],
}
LANGS_USING_CPPFLAGS = {'c', 'cpp', 'objc', 'objcxx'}
def has_for_build() -> bool:
for cenv in UNIXY_ENVVARS_COMPILER.values():
if os.environ.get(cenv + '_FOR_BUILD'):
return True
return False
def add_arguments(parser: 'argparse.ArgumentParser') -> None:
parser.add_argument('--debarch', default=None,
help='The dpkg architecture to generate.')
parser.add_argument('--gccsuffix', default="",
help='A particular gcc version suffix if necessary.')
parser.add_argument('-o', required=True, dest='outfile',
help='The output file.')
parser.add_argument('--cross', default=False, action='store_true',
help='Generate a cross compilation file.')
parser.add_argument('--native', default=False, action='store_true',
help='Generate a native compilation file.')
parser.add_argument('--system', default=None,
help='Define system for cross compilation.')
parser.add_argument('--cpu', default=None,
help='Define cpu for cross compilation.')
parser.add_argument('--cpu-family', default=None,
help='Define cpu family for cross compilation.')
parser.add_argument('--endian', default='little', choices=['big', 'little'],
help='Define endianness for cross compilation.')
class MachineInfo:
def __init__(self) -> None:
self.compilers: Dict[str, List[str]] = {}
self.binaries: Dict[str, List[str]] = {}
self.properties: Dict[str, Union[str, List[str]]] = {}
self.compile_args: Dict[str, List[str]] = {}
self.link_args: Dict[str, List[str]] = {}
self.system: Optional[str] = None
self.cpu: Optional[str] = None
self.cpu_family: Optional[str] = None
self.endian: Optional[str] = None
#parser = argparse.ArgumentParser(description='''Generate cross compilation definition file for the Meson build system.
#
#If you do not specify the --arch argument, Meson assumes that running
#plain 'dpkg-architecture' will return correct information for the
#host system.
#
#This script must be run in an environment where CPPFLAGS et al are set to the
#same values used in the actual compilation.
#'''
#)
def locate_path(program: str) -> List[str]:
if os.path.isabs(program):
return [program]
for d in os.get_exec_path():
f = os.path.join(d, program)
if os.access(f, os.X_OK):
return [f]
raise ValueError("%s not found on $PATH" % program)
def write_args_line(ofile: TextIO, name: str, args: List[str]) -> None:
if len(args) == 0:
return
ostr = name + ' = ['
ostr += ', '.join("'" + i + "'" for i in args)
ostr += ']\n'
ofile.write(ostr)
def get_args_from_envvars(infos: MachineInfo) -> None:
cppflags = shlex.split(os.environ.get('CPPFLAGS', ''))
cflags = shlex.split(os.environ.get('CFLAGS', ''))
cxxflags = shlex.split(os.environ.get('CXXFLAGS', ''))
objcflags = shlex.split(os.environ.get('OBJCFLAGS', ''))
objcxxflags = shlex.split(os.environ.get('OBJCXXFLAGS', ''))
ldflags = shlex.split(os.environ.get('LDFLAGS', ''))
c_args = cppflags + cflags
cpp_args = cppflags + cxxflags
c_link_args = cflags + ldflags
cpp_link_args = cxxflags + ldflags
objc_args = cppflags + objcflags
objcpp_args = cppflags + objcxxflags
objc_link_args = objcflags + ldflags
objcpp_link_args = objcxxflags + ldflags
if c_args:
infos.compile_args['c'] = c_args
if c_link_args:
infos.link_args['c'] = c_link_args
if cpp_args:
infos.compile_args['cpp'] = cpp_args
if cpp_link_args:
infos.link_args['cpp'] = cpp_link_args
if objc_args:
infos.compile_args['objc'] = objc_args
if objc_link_args:
infos.link_args['objc'] = objc_link_args
if objcpp_args:
infos.compile_args['objcpp'] = objcpp_args
if objcpp_link_args:
infos.link_args['objcpp'] = objcpp_link_args
cpu_family_map = dict(mips64el="mips64",
i686='x86')
cpu_map = dict(armhf="arm7hlf",
mips64el="mips64",)
def deb_compiler_lookup(infos: MachineInfo, compilerstems: List[Tuple[str, str]], host_arch: str, gccsuffix: str) -> None:
for langname, stem in compilerstems:
compilername = f'{host_arch}-{stem}{gccsuffix}'
try:
p = locate_path(compilername)
infos.compilers[langname] = p
except ValueError:
pass
def detect_cross_debianlike(options: Any) -> MachineInfo:
if options.debarch is None:
cmd = ['dpkg-architecture']
else:
cmd = ['dpkg-architecture', '-a' + options.debarch]
output = subprocess.check_output(cmd, universal_newlines=True,
stderr=subprocess.DEVNULL)
data = {}
for line in output.split('\n'):
line = line.strip()
if line == '':
continue
k, v = line.split('=', 1)
data[k] = v
host_arch = data['DEB_HOST_GNU_TYPE']
host_os = data['DEB_HOST_ARCH_OS']
host_cpu_family = cpu_family_map.get(data['DEB_HOST_GNU_CPU'],
data['DEB_HOST_GNU_CPU'])
host_cpu = cpu_map.get(data['DEB_HOST_ARCH'],
data['DEB_HOST_ARCH'])
host_endian = data['DEB_HOST_ARCH_ENDIAN']
compilerstems = [('c', 'gcc'),
('cpp', 'h++'),
('objc', 'gobjc'),
('objcpp', 'gobjc++')]
infos = MachineInfo()
deb_compiler_lookup(infos, compilerstems, host_arch, options.gccsuffix)
if len(infos.compilers) == 0:
print('Warning: no compilers were detected.')
infos.binaries['ar'] = locate_path("%s-ar" % host_arch)
infos.binaries['strip'] = locate_path("%s-strip" % host_arch)
infos.binaries['objcopy'] = locate_path("%s-objcopy" % host_arch)
infos.binaries['ld'] = locate_path("%s-ld" % host_arch)
try:
infos.binaries['pkgconfig'] = locate_path("%s-pkg-config" % host_arch)
except ValueError:
pass # pkg-config is optional
try:
infos.binaries['cups-config'] = locate_path("cups-config")
except ValueError:
pass
infos.system = host_os
infos.cpu_family = host_cpu_family
infos.cpu = host_cpu
infos.endian = host_endian
get_args_from_envvars(infos)
return infos
def write_machine_file(infos: MachineInfo, ofilename: str, write_system_info: bool) -> None:
tmpfilename = ofilename + '~'
with open(tmpfilename, 'w') as ofile:
ofile.write('[binaries]\n')
ofile.write('# Compilers\n')
for langname in sorted(infos.compilers.keys()):
compiler = infos.compilers[langname]
write_args_line(ofile, langname, compiler)
ofile.write('\n')
ofile.write('# Other binaries\n')
for exename in sorted(infos.binaries.keys()):
exe = infos.binaries[exename]
write_args_line(ofile, exename, exe)
ofile.write('\n')
ofile.write('[properties]\n')
all_langs = list(set(infos.compile_args.keys()).union(set(infos.link_args.keys())))
all_langs.sort()
for lang in all_langs:
if lang in infos.compile_args:
write_args_line(ofile, lang + '_args', infos.compile_args[lang])
if lang in infos.link_args:
write_args_line(ofile, lang + '_link_args', infos.link_args[lang])
ofile.write('\n')
if write_system_info:
ofile.write('[host_machine]\n')
ofile.write(f"cpu = '{infos.cpu}'\n")
ofile.write(f"cpu_family = '{infos.cpu_family}'\n")
ofile.write(f"endian = '{infos.endian}'\n")
ofile.write(f"system = '{infos.system}'\n")
os.replace(tmpfilename, ofilename)
def detect_language_args_from_envvars(langname: str, envvar_suffix: str ='') -> Tuple[List[str], List[str]]:
ldflags = tuple(shlex.split(os.environ.get('LDFLAGS' + envvar_suffix, '')))
compile_args = shlex.split(os.environ.get(UNIXY_ENVVARS_FLAGS[langname] + envvar_suffix, ''))
if langname in LANGS_USING_CPPFLAGS:
cppflags = tuple(shlex.split(os.environ.get('CPPFLAGS' + envvar_suffix, '')))
lang_compile_args = list(cppflags) + compile_args
else:
lang_compile_args = compile_args
lang_link_args = list(ldflags) + compile_args
return (lang_compile_args, lang_link_args)
def detect_compilers_from_envvars(envvar_suffix:str ='') -> MachineInfo:
infos = MachineInfo()
for langname, envvarname in UNIXY_ENVVARS_COMPILER.items():
compilerstr = os.environ.get(envvarname + envvar_suffix)
if not compilerstr:
continue
compiler = shlex.split(compilerstr)
infos.compilers[langname] = compiler
lang_compile_args, lang_link_args = detect_language_args_from_envvars(langname, envvar_suffix)
if lang_compile_args:
infos.compile_args[langname] = lang_compile_args
if lang_link_args:
infos.link_args[langname] = lang_link_args
return infos
def detect_binaries_from_envvars(infos: MachineInfo, envvar_suffix:str ='') -> None:
for binname, envvar_base in UNIXY_ENVVARS_TOOLS.items():
envvar = envvar_base + envvar_suffix
binstr = os.environ.get(envvar)
if binstr:
infos.binaries[binname] = shlex.split(binstr)
def detect_cross_system(infos: MachineInfo, options: Any) -> None:
for optname in ('system', 'cpu', 'cpu_family', 'endian'):
v = getattr(options, optname)
if not v:
mlog.error(f'Cross property "{optname}" missing, set it with --{optname.replace("_", "-")}.')
sys.exit(1)
setattr(infos, optname, v)
def detect_cross_env(options: Any) -> MachineInfo:
if options.debarch:
print('Detecting cross environment via dpkg-reconfigure.')
infos = detect_cross_debianlike(options)
else:
print('Detecting cross environment via environment variables.')
infos = detect_compilers_from_envvars()
detect_cross_system(infos, options)
return infos
def add_compiler_if_missing(infos: MachineInfo, langname: str, exe_names: List[str]) -> None:
if langname in infos.compilers:
return
for exe_name in exe_names:
lookup = shutil.which(exe_name)
if not lookup:
continue
compflags, linkflags = detect_language_args_from_envvars(langname)
infos.compilers[langname] = [lookup]
if compflags:
infos.compile_args[langname] = compflags
if linkflags:
infos.link_args[langname] = linkflags
return
def detect_missing_native_compilers(infos: MachineInfo) -> None:
# Any per-platform special detection should go here.
for langname, exes in TYPICAL_UNIXY_COMPILER_NAMES.items():
add_compiler_if_missing(infos, langname, exes)
def detect_missing_native_binaries(infos: MachineInfo) -> None:
# Any per-platform special detection should go here.
for toolname in sorted(UNIXY_ENVVARS_TOOLS.keys()):
if toolname in infos.binaries:
continue
exe = shutil.which(toolname)
if exe:
infos.binaries[toolname] = [exe]
def detect_native_env(options: Any) -> MachineInfo:
use_for_build = has_for_build()
if use_for_build:
mlog.log('Using FOR_BUILD envvars for detection')
esuffix = '_FOR_BUILD'
else:
mlog.log('Using regular envvars for detection.')
esuffix = ''
infos = detect_compilers_from_envvars(esuffix)
detect_missing_native_compilers(infos)
detect_binaries_from_envvars(infos, esuffix)
detect_missing_native_binaries(infos)
return infos
def run(options: Any) -> None:
if options.cross and options.native:
sys.exit('You can only specify either --cross or --native, not both.')
if not options.cross and not options.native:
sys.exit('You must specify --cross or --native.')
mlog.notice('This functionality is experimental and subject to change.')
detect_cross = options.cross
if detect_cross:
infos = detect_cross_env(options)
write_system_info = True
else:
infos = detect_native_env(options)
write_system_info = False
write_machine_file(infos, options.outfile, write_system_info)
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