DTrace on RHEL7, generated Include/pydtrace_probes.h fails to build: error: impossible constraint in ‘asm’

[vstinner]

BPO	45157
Nosy	@vstinner, @stratakis, @hroncok

^{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 = None
closed_at = <Date 2021-09-13.20:53:52.319>
created_at = <Date 2021-09-09.22:37:07.884>
labels = ['build', '3.10', '3.11']
title = 'DTrace on RHEL7, generated Include/pydtrace_probes.h fails to build: error: impossible constraint in \xe2\x80\x98asm\xe2\x80\x99'
updated_at = <Date 2021-09-13.20:53:52.318>
user = 'https://github.com/vstinner'

bugs.python.org fields:

activity = <Date 2021-09-13.20:53:52.318>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2021-09-13.20:53:52.319>
closer = 'vstinner'
components = ['Build']
creation = <Date 2021-09-09.22:37:07.884>
creator = 'vstinner'
dependencies = []
files = []
hgrepos = []
issue_num = 45157
keywords = []
message_count = 3.0
messages = ['401526', '401527', '401733']
nosy_count = 3.0
nosy_names = ['vstinner', 'cstratak', 'hroncok']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = None
url = 'https://bugs.python.org/issue45157'
versions = ['Python 3.10', 'Python 3.11']

[vstinner]

I modified RHEL7 configuration to build Python using --with-dtrace:

argv: [b'./configure', b'--prefix', b'$(PWD)/target', b'--with-pydebug', b'--with-platlibdir=lib64', b'--enable-ipv6', b'--enable-shared', b'--with-computed-gotos=yes', b'--with-dbmliborder=gdbm:ndbm:bdb', b'--enable-loadable-sqlite-extensions', b'--with-dtrace', b'--with-lto', b'--with-ssl-default-suites=openssl', b'--without-static-libpython', b'--with-valgrind']

Problem: the generated Include/pydtrace_probes.h failed to build :-(

---
/usr/bin/dtrace -o Include/pydtrace_probes.h -h -s Include/pydtrace.d
sed 's/PYTHON_/PyDTrace_/' Include/pydtrace_probes.h > Include/pydtrace_probes.h.tmp
mv Include/pydtrace_probes.h.tmp Include/pydtrace_probes.h
(...)
In file included from ./Include/pydtrace_probes.h:10:0,
from ./Include/pydtrace.h:11,
from Modules/gcmodule.c:33:
Modules/gcmodule.c: In function ‘gc_collect_main’:
./Include/pydtrace_probes.h:98:1: error: impossible constraint in ‘asm’
DTRACE_PROBE1 (python, gc__start, arg1)
^
./Include/pydtrace_probes.h:109:1: error: impossible constraint in ‘asm’
DTRACE_PROBE1 (python, gc__done, arg1)
^
---

Full logs of AMD64 RHEL7 3.x:
https://buildbot.python.org/all/#/builders/15/builds/761

In the meantime, I disabled --with-dtrace since other buildbot workers failed when dtrace was no installed. See:
python/buildmaster-config#264

Maybe it's a problem on RHEL7. Maybe the problem is that Python is built with LTO?

[vstinner]

Similar error with Python 3.10, AMD64 RHEL7 3.10 logs:
https://buildbot.python.org/all/#/builders/666/builds/344

[vstinner]

Issue worked around by disabling LTO on RHEL7 buildbots:
python/buildmaster-config@b8e56c0