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Fix Program/_freeze_module for cross compiling Python #90044
Description
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = 'https://github.com/tiran'
closed_at = None
created_at = <Date 2021-11-23.22:35:22.196>
labels = ['type-feature', 'build', '3.11']
title = 'Fix Program/_freeze_module for cross compiling Python'
updated_at = <Date 2022-03-31.17:54:40.972>
user = 'https://github.com/tiran'bugs.python.org fields:
activity = <Date 2022-03-31.17:54:40.972>
actor = 'brett.cannon'
assignee = 'christian.heimes'
closed = False
closed_date = None
closer = None
components = ['Build']
creation = <Date 2021-11-23.22:35:22.196>
creator = 'christian.heimes'
dependencies = []
files = []
hgrepos = []
issue_num = 45886
keywords = ['patch']
message_count = 8.0
messages = ['406893', '406898', '406904', '406988', '407006', '407062', '407267', '407272']
nosy_count = 5.0
nosy_names = ['gvanrossum', 'brett.cannon', 'christian.heimes', 'eric.snow', 'iritkatriel']
pr_nums = ['29735', '29793']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue45886'
versions = ['Python 3.11']
Activity
tiran commentedon Nov 23, 2021
The build process creates the binary Program/_freeze_module, which is used to create frozen modules. The program takes a Python file, compiles it, and stores its marshalled output in a header file.
The approach does not work when cross compiling Python. In cross building case Program/_freeze_module cannot be executed on the build host. For example a cross build with build host "x86_64" and target host "aarch64" would create a aarch64 Program/_freeze_module. The current x86_64 host cannot executed binary (unless you use qemu and binfmt, which I'm deliberately ignoring here).
To unblock cross building and until we find a better solution, I propose that we allow developers to override the freeze module command on the command line. This allows developers to use a freeze_module program from a non-cross build:
../../configure -C --host=aarch64-linux-gnu-gcc --build=x86_64-pc-linux-gnu
make FREEZE_MODULE=../x86_64/Program/_freeze_module
gvanrossum commentedon Nov 23, 2021
To the question "why does _freeze_module need to be a (C) binary" (IOW, why can't it be replaced by a Python script that is run with PYTHON_FOR_REGEN, which always runs on the build host), the reason is that it uses the bytecode compiler to generate correct output. The bytecode compiler is written in C and depends on many other parts of the runtime. Bytecode is not compatible between versions (and in 3.11 it is an especially moving target) so we absolutely must use the bytecode compiler from the current source tree.
Fortunately bytecode *is* portable across OS and CPU versions, so there is no problem with taking a _freeze_module binary compiled for the build host and running it there (on the build host). It *is* complicated to build a binary for the build host in a tree configured for cross compilation though -- you'd have to do an out-of-tree build configured for the build host platform. Rather than solving *that* problem, Christian proposes to let the user solve that, and allowing the user to pass in the path to the host platform _freeze_module binary.
tiran commentedon Nov 24, 2021
New changeset dd8ce9e by Christian Heimes in branch 'main':
bpo-45886: Allow overriding freeze command for cross compiling (GH-29735)
dd8ce9e
tiran commentedon Nov 25, 2021
The FREEZE_MODULE trick fails with out-of-tree builds when SRCDIR contains the frozen_modules header files from a previous build. When doing OOT building, make includes the SRCDIR in the search path for dependencies (VPATH). It considers$(srcdir)/Python/frozen_modules/importlib._bootstrap_external.h as recent enough and therefore does not generate $ (builddir)/Python/frozen_modules/importlib._bootstrap_external.h. The freeze_module program does not know about VPATH and looks up the file in the $(builddir) tree:
$ make FREEZE_MODULE=/cpython/builddep/ubuntu-impish-x86_64/Programs/_freeze_module Python/frozen_modules/importlib._bootstrap_external.h make: '../../Python/frozen_modules/importlib._bootstrap_external.h' is up to date.I see two possible solutions for the problem:
make cleanto also remove $(FROZEN_FILES_OUT). The make clean command is suppose to remove all files that interferes with OOT builds (see check-clean-src in Makefile.pre.in).gvanrossum commentedon Nov 25, 2021
Imthink I prefer the ‘make clean’ extension.--
--Guido (mobile)
tiran commentedon Nov 26, 2021
New changeset 765b2a3 by Christian Heimes in branch 'main':
bpo-45886: Fix OOT build when srcdir has frozen module headers (GH-29793)
765b2a3
iritkatriel commentedon Nov 29, 2021
Is this related to this issue or something else?
https://buildbot.python.org/all/#/builders/310/builds/344
gcc -pthread -c -Wsign-compare -g -Og -Wall -std=c99 -Wextra -Wno-unused-parameter -Wno-missing-field-initializers -Werror=implicit-function-declaration -fvisibility=hidden -I./Include/internal -I. -I./Include -DPy_BUILD_CORE -o Programs/_freeze_module.o Programs/_freeze_module.c
gcc -pthread -o Programs/_freeze_module Programs/_freeze_module.o Modules/getbuildinfo.o Parser/token.o Parser/pegen.o Parser/pegen_errors.o Parser/action_helpers.o Parser/parser.o Parser/string_parser.o Parser/peg_api.o Parser/myreadline.o Parser/tokenizer.o Objects/abstract.o Objects/accu.o Objects/boolobject.o Objects/bytes_methods.o Objects/bytearrayobject.o Objects/bytesobject.o Objects/call.o Objects/capsule.o Objects/cellobject.o Objects/classobject.o Objects/codeobject.o Objects/complexobject.o Objects/descrobject.o Objects/enumobject.o Objects/exceptions.o Objects/genericaliasobject.o Objects/genobject.o Objects/fileobject.o Objects/floatobject.o Objects/frameobject.o Objects/funcobject.o Objects/interpreteridobject.o Objects/iterobject.o Objects/listobject.o Objects/longobject.o Objects/dictobject.o Objects/odictobject.o Objects/memoryobject.o Objects/methodobject.o Objects/moduleobject.o Objects/namespaceobject.o Objects/object.o Objects/obmalloc.o Objects/picklebufobject.o Objects/rangeobject.o Objects/setobject.o Objects/sliceobject.o Objects/structseq.o Objects/tupleobject.o Objects/typeobject.o Objects/unicodeobject.o Objects/unicodectype.o Objects/unionobject.o Objects/weakrefobject.o Python/_warnings.o Python/Python-ast.o Python/Python-tokenize.o Python/asdl.o Python/ast.o Python/ast_opt.o Python/ast_unparse.o Python/bltinmodule.o Python/ceval.o Python/codecs.o Python/compile.o Python/context.o Python/dynamic_annotations.o Python/errors.o Python/frame.o Python/frozenmain.o Python/future.o Python/getargs.o Python/getcompiler.o Python/getcopyright.o Python/getplatform.o Python/getversion.o Python/hamt.o Python/hashtable.o Python/import.o Python/importdl.o Python/initconfig.o Python/marshal.o Python/modsupport.o Python/mysnprintf.o Python/mystrtoul.o Python/pathconfig.o Python/preconfig.o Python/pyarena.o Python/pyctype.o Python/pyfpe.o Python/pyhash.o Python/pylifecycle.o Python/pymath.o Python/pystate.o Python/pythonrun.o Python/pytime.o Python/bootstrap_hash.o Python/specialize.o Python/structmember.o Python/symtable.o Python/sysmodule.o Python/thread.o Python/traceback.o Python/getopt.o Python/pystrcmp.o Python/pystrtod.o Python/pystrhex.o Python/dtoa.o Python/formatter_unicode.o Python/fileutils.o Python/suggestions.o Python/dynload_shlib.o Modules/config.o Modules/getpath.o Modules/main.o Modules/gcmodule.o Modules/atexitmodule.o Modules/faulthandler.o Modules/posixmodule.o Modules/signalmodule.o Modules/_tracemalloc.o Modules/_codecsmodule.o Modules/_collectionsmodule.o Modules/errnomodule.o Modules/_io/_iomodule.o Modules/_io/iobase.o Modules/_io/fileio.o Modules/_io/bytesio.o Modules/_io/bufferedio.o Modules/_io/textio.o Modules/_io/stringio.o Modules/itertoolsmodule.o Modules/_sre.o Modules/_threadmodule.o Modules/timemodule.o Modules/_weakref.o Modules/_abc.o Modules/_functoolsmodule.o Modules/_localemodule.o Modules/_operator.o Modules/_stat.o Modules/symtablemodule.o Modules/pwdmodule.o Modules/xxsubtype.o -lpthread -ldl -lutil -lm
Programs/_freeze_module importlib._bootstrap ./Lib/importlib/_bootstrap.py Python/frozen_modules/importlib._bootstrap.h
python3 ./Tools/scripts/deepfreeze.py Python/frozen_modules/importlib._bootstrap.h -m importlib._bootstrap -o Python/deepfreeze/importlib._bootstrap.c
File "./Tools/scripts/deepfreeze.py", line 29
res.append(f"\\x{i:02x}")
^
SyntaxError: invalid syntax
Makefile:1069: recipe for target 'Python/deepfreeze/importlib._bootstrap.c' failed
make: *** [Python/deepfreeze/importlib._bootstrap.c] Error 1
program finished with exit code 2
elapsedTime=45.181814
tiran commentedon Nov 29, 2021
The issue is related to bpo-45873. The Debian buildbot has an ancient Python version that does not support f-strings.
kumaraditya303 commentedon May 9, 2022
Can this be closed now ?
gvanrossum commentedon May 9, 2022
I guess so. (@tiran If there's still something to do here feel free to reopen.)