This option changes the behavior of --enable-shared to continue to build
the libpython3.x.so shared library, but not use it for linking the
python3 interpreter executable. Instead, the executable is linked
directly against the libpython .o files as it would be with
--disable-shared.
There are two benefits of this change. First, libpython uses
thread-local storage, which is noticeably slower when used in a loaded
module instead of in the main program, because the main program can take
advantage of constant offsets from the thread state pointer but loaded
modules have to dynamically call a function __tls_get_addr() to
potentially allocate their thread-local storage area. (There is another
thread-local storage model for dynamic libraries which mitigates most of
this performance hit, but it comes at the cost of preventing
dlopen("libpython3.x.so"), which is a use case we want to preserve.)
Second, this improves the user experience around relocatable Python a
little bit, in that we don't need to use an $ORIGIN-relative path to
locate libpython3.x.so, which has some mild benefits around musl (which
does not support $ORIGIN-relative DT_NEEDED, only $ORIGIN-relative
DT_RPATH/DT_RUNPATH), users who want to make the interpreter setuid or
setcap (which prevents processing $ORIGIN), etc.
* introduce executable specific linker flags
Add PY_CORE_EXE_LDFLAGS and EXE_LDFLAGS which stores executable specific
LDFLAGS, replacing PY_CORE_LDFLAGS for building
executable targets.
If PY_CORE_EXE_LDFLAGS / EXE_LDFLAGS is not provided, then it defaults
to the value of PY_CORE_LDFLAGS which is the existing behaviour.
If both flags are supplied, and there is a need
to distinguish between executable and shared specific LDFLAGS,
in particular, PY_CORE_LDFLAGS should contain the shared specific LDFLAGS.
* documentation for new linker flags
* update Misc folder documentation
* Update Makefile.pre.in
Co-authored-by: Victor Stinner <vstinner@python.org>
---------
Co-authored-by: Filipe Laíns <filipe.lains@gmail.com>
Co-authored-by: Victor Stinner <vstinner@python.org>
Co-authored-by: Filipe Laíns <lains@riseup.net>
The pymalloc huge page support had two problems. First, on
architectures where the default huge page size exceeds the arena
size (e.g. 32 MiB on PPC, 512 MiB on ARM64 with 64 KB base
pages), mmap with MAP_HUGETLB silently allocates a full huge page
even when the requested size is smaller. The subsequent munmap
with the original arena size then fails with EINVAL, permanently
leaking the entire huge page. Second, huge pages were always
attempted when compiled in, with no way to disable them at
runtime. On Linux, if the huge page pool is exhausted, page
faults including copy-on-write faults after fork deliver SIGBUS
and kill the process.
The arena allocator now queries the system huge page size from
/proc/meminfo and skips MAP_HUGETLB when the arena size is not a
multiple of it. Huge pages also now require explicit opt-in at
runtime via the PYTHON_PYMALLOC_HUGEPAGES environment variable,
which is read through PyConfig and respects -E and -I flags.
The config field pymalloc_hugepages is propagated to the runtime
allocators struct so the low-level arena allocator can check it
without calling getenv directly.
Adds a PrivacyInfo.xcprivacy file when packaging `_hashlib` and `_ssl` modules
for iOS (based on the original OpenSSL sources); and adds handling to the build
script to allow any app to add `xcprivacy` handling for a binary module.
Adds tooling to generate and test an iOS XCframework, in a way that will also facilitate
adding other XCframework targets for other Apple platforms (tvOS, watchOS, visionOS and
even macOS, potentially).
---------
Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>
Modifies the iOS testbed project to add a test plan. This simplifies the iOS
test runner, as we can now use the built-in log streaming to see test results.
It also allows for some other affordances, like providing a default LLDB config,
and using a standardized mechanism for specifying test arguments.
partev