On Fedora 40+ x86_64 and aarch64, build Python with the experimental JIT compiler

python3.13.spec

@@ -17,7 +17,7 @@ URL: https://www.python.org/
 %global prerel b2
 %global upstream_version %{general_version}%{?prerel}
 Version: %{general_version}%{?prerel:~%{prerel}}
-Release: 3%{?dist}
+Release: 4%{?dist}
 License: Python-2.0.1
 
 
@@ -138,6 +138,22 @@ Provides: bundled(python3dist(packaging)) = 24
 # (the -freethreading subpackage)
 %bcond_without freethreading_build
 
+# PEP 744: JIT Compilation
+# Whether to build with the experimental JIT compiler
+# We can only have this on Fedora 40+, where clang 18+ is available
+# And only on certain architectures: https://peps.python.org/pep-0744/#support
+# The freethreading build (when enabled) does not support JIT yet
+%bcond_with jit
+%ifarch x86_64 aarch64
+%if 0%{?fedora} >= 40 || 0%{?rhel} >= 10
+%bcond_without jit
+%endif
+%endif
+%if %{with jit}
+# When built with JIT, it still needs to be enabled on runtime via PYTHON_JIT=1
+%global jit_flag --enable-experimental-jit=yes-off
+%endif
+
 # Support for the GDB debugger
 %bcond_without gdb_hooks
 
@@ -299,6 +315,11 @@ BuildRequires: tcl-devel
 BuildRequires: tk-devel
 BuildRequires: tzdata
 
+%if %{with jit}
+BuildRequires: clang(major) = 18
+BuildRequires: llvm(major) = 18
+%endif
+
 %if %{with valgrind}
 BuildRequires: valgrind-devel
 %endif
@@ -373,6 +394,12 @@ Source11: idle3.appdata.xml
 # pypa/distutils integration: https://github.com/pypa/distutils/pull/70
 Patch251: 00251-change-user-install-location.patch
 
+# 00429 # fa7831be5e5365646d4dd400e23e977f83f64923
+# GH-118943: Fix another race condition when generating jit_stencils.h
+#
+# Another process might have already moved jit_stencils.h.new
+Patch429: 00429-gh-118943-fix-another-race-condition-when-generating-jit_stencils-h.patch
+
 # (New patches go here ^^^)
 #
 # When adding new patches to "python" and "python3" in Fedora, EL, etc.,
@@ -906,12 +933,12 @@ BuildPython() {
 # option produces too many warnings when compiling at the O0 optimization level.
 # See also: https://bugzilla.redhat.com/show_bug.cgi?id=1818857
 BuildPython debug \
-  "--without-ensurepip --with-pydebug" \
+  "--without-ensurepip --with-pydebug %{?jit_flag}" \
   "%{optflags_debug}"
 %endif # with debug_build
 
 BuildPython optimized \
-  "--without-ensurepip %{optimizations_flag}" \
+  "--without-ensurepip %{?jit_flag} %{optimizations_flag}" \
   "%{optflags_optimized}"
 
 %if %{with freethreading_build} && %{with debug_build}
@@ -1687,6 +1714,11 @@ CheckPython freethreading
 # ======================================================
 
 %changelog
+* Tue Jun 18 2024 Miro Hrončok <mhroncok@redhat.com> - 3.13.0~b2-4
+- On Fedora 40+ x86_64 and aarch64, build Python with the experimental JIT compiler
+- To enable it on runtime, set the PYTHON_JIT environment variable to 1
+- https://peps.python.org/pep-0744/
+
 * Thu Jun 06 2024 Python Maint <python-maint@redhat.com> - 3.13.0~b2-3
 - Rebuilt for Python 3.13