gh-160689 : Link only the bootstrap modules into the build helper programs (#160537)

The build-helper programs (`Programs/_freeze_module` and `_bootstrap_python`) don't need to link extension modules that they don't need.

This PR makes sure the helper programs get only the modules they need to do their job, regardless of what the build configuration sets for the final built runtime and interpreter.

This follows the same pattern as what `PCbuild/_freeze_module.vcxproj` does with `PC/config_minimal.c`, and lets "extra" builtin modules (from `Setup.local` or `MODULE_BUILDTYPE=static`) depend on frozen modules or `getpath`.

.gitignore

@@ -102,6 +102,7 @@ Modules/Setup.config
 Modules/Setup.local
 Modules/Setup.stdlib
 Modules/config.c
+Modules/config_bootstrap.c
 Modules/ld_so_aix
 Programs/_freeze_module
 Programs/_testembed

Makefile.pre.in

@@ -25,6 +25,13 @@ MODSHARED_NAMES=   _MODSHARED_NAMES_
 MODDISABLED_NAMES= _MODDISABLED_NAMES_
 MODOBJS=           _MODOBJS_
 MODLIBS=           _MODLIBS_
+# Objects and libraries of the bootstrap modules (Modules/Setup.bootstrap)
+# only. These are the only static modules linked into the build helper
+# programs (Programs/_freeze_module, _bootstrap_python), so that other
+# builtin modules (Modules/Setup.local, MODULE_BUILDTYPE=static) may depend
+# on products of those helpers (frozen modules, getpath).
+BOOTSTRAP_MODOBJS= _BOOTSTRAP_MODOBJS_
+BOOTSTRAP_MODLIBS= _BOOTSTRAP_MODLIBS_
 
 # === Variables set by configure
 VERSION=	@VERSION@
@@ -359,11 +366,14 @@ COVERAGE_REPORT_OPTIONS=--rc lcov_branch_coverage=1 --branch-coverage --title "C
 
 ##########################################################################
 # Modules
-MODULE_OBJS=	\
-		Modules/config.o \
+MODULE_OBJS_COMMON=	\
 		Modules/main.o \
 		Modules/gcmodule.o
 
+MODULE_OBJS=	\
+		Modules/config.o \
+		$(MODULE_OBJS_COMMON)
+
 IO_H=		Modules/_io/_iomodule.h
 
 IO_OBJS=	\
@@ -614,6 +624,19 @@ LIBRARY_OBJS=	\
 		Modules/getpath.o \
 		Python/frozen.o
 
+# objects that get linked into the build helper programs
+# (Programs/_freeze_module, _bootstrap_python): the core, plus the bootstrap
+# modules only (see BOOTSTRAP_MODOBJS). Does not include frozen modules nor
+# getpath, which the helpers are used to build.
+BOOTSTRAP_LIBRARY_OBJS=	\
+		Modules/getbuildinfo_bootstrap.o \
+		$(PARSER_OBJS) \
+		$(OBJECT_OBJS) \
+		$(PYTHON_OBJS) \
+		Modules/config_bootstrap.o \
+		$(MODULE_OBJS_COMMON) \
+		$(BOOTSTRAP_MODOBJS)
+
 LINK_PYTHON_OBJS=@LINK_PYTHON_OBJS@
 
 ##########################################################################
@@ -1613,7 +1636,7 @@ Modules/Setup.bootstrap: $(srcdir)/Modules/Setup.bootstrap.in config.status
 Modules/Setup.stdlib: $(srcdir)/Modules/Setup.stdlib.in config.status
 	./config.status $@
 
-Makefile Modules/config.c: Makefile.pre \
+Makefile Modules/config.c Modules/config_bootstrap.c: Makefile.pre \
 				$(srcdir)/Modules/config.c.in \
 				$(MAKESETUP) \
 				$(srcdir)/Modules/Setup \
@@ -1624,9 +1647,9 @@ Makefile Modules/config.c: Makefile.pre \
 				-s Modules \
 				Modules/Setup.local \
 				Modules/Setup.stdlib \
-				Modules/Setup.bootstrap \
+				-b Modules/Setup.bootstrap \
 				$(srcdir)/Modules/Setup
-	@mv config.c Modules
+	@mv config.c config_bootstrap.c Modules
 	@echo "The Makefile was updated, you may need to re-run make."
 
 .PHONY: regen-test-frozenmain
@@ -1661,9 +1684,9 @@ BOOTSTRAP_HEADERS = \
 
 Programs/_bootstrap_python.o: Programs/_bootstrap_python.c $(BOOTSTRAP_HEADERS) $(PYTHON_HEADERS)
 
-_bootstrap_python: $(LIBRARY_OBJS_OMIT_FROZEN) Programs/_bootstrap_python.o Modules/getpath.o Modules/Setup.local
-	$(LINKCC) $(PY_LDFLAGS_NOLTO) -o $@ $(LIBRARY_OBJS_OMIT_FROZEN) \
-		Programs/_bootstrap_python.o Modules/getpath.o $(LIBS) $(MODLIBS) $(SYSLIBS)
+_bootstrap_python: $(BOOTSTRAP_LIBRARY_OBJS) Programs/_bootstrap_python.o Modules/getpath.o Modules/Setup.local
+	$(LINKCC) $(PY_LDFLAGS_NOLTO) -o $@ $(BOOTSTRAP_LIBRARY_OBJS) \
+		Programs/_bootstrap_python.o Modules/getpath.o $(LIBS) $(BOOTSTRAP_MODLIBS) $(SYSLIBS)
 	# Dummy pybuilddir.txt  is needed for _bootstrap_python to be runnable
 	@echo "none" > ./pybuilddir.txt
 
@@ -1681,6 +1704,9 @@ _bootstrap_python: $(LIBRARY_OBJS_OMIT_FROZEN) Programs/_bootstrap_python.o Modu
 #
 # Standard build process:
 # 1) compile minimal core objects for Py_Compile*() and PyMarshal_Write*().
+#    Only the bootstrap modules (Modules/Setup.bootstrap) are part of these
+#    objects (see BOOTSTRAP_LIBRARY_OBJS), so other builtin modules may
+#    depend on the output of the following steps.
 # 2) build Programs/_freeze_module binary.
 # 3) create frozen module headers for importlib and getpath.
 # 4) build _bootstrap_python binary.
@@ -1753,8 +1779,8 @@ Programs/_freeze_module.o: Programs/_freeze_module.c Makefile
 
 Modules/getpath_noop.o: $(srcdir)/Modules/getpath_noop.c Makefile
 
-Programs/_freeze_module: Programs/_freeze_module.o Modules/getpath_noop.o $(LIBRARY_OBJS_OMIT_FROZEN)
-	$(LINKCC) $(PY_CORE_LDFLAGS) -o $@ Programs/_freeze_module.o Modules/getpath_noop.o $(LIBRARY_OBJS_OMIT_FROZEN) $(LIBS) $(MODLIBS) $(SYSLIBS)
+Programs/_freeze_module: Programs/_freeze_module.o Modules/getpath_noop.o $(BOOTSTRAP_LIBRARY_OBJS)
+	$(LINKCC) $(PY_CORE_LDFLAGS) -o $@ Programs/_freeze_module.o Modules/getpath_noop.o $(BOOTSTRAP_LIBRARY_OBJS) $(LIBS) $(BOOTSTRAP_MODLIBS) $(SYSLIBS)
 
 # We manually freeze getpath.py rather than through freeze_modules
 Python/frozen_modules/getpath.h: Modules/getpath.py $(FREEZE_MODULE_BOOTSTRAP_DEPS)
@@ -1907,11 +1933,24 @@ Modules/getbuildinfo.o: $(PARSER_OBJS) \
 		$(MODOBJS) \
 		$(DTRACE_OBJS) \
 		$(srcdir)/Modules/getbuildinfo.c
-	$(CC) -c $(PY_CORE_CFLAGS) \
+	$(CC) -c $(PY_CORE_CFLAGS) $(GETBUILDINFO_CFLAGS) \
+	      -o $@ $(srcdir)/Modules/getbuildinfo.c
+
+# Separate object for the build helper programs: it must not depend on
+# $(MODOBJS), which may in turn depend on the helpers' output.
+Modules/getbuildinfo_bootstrap.o: $(PARSER_OBJS) \
+		$(OBJECT_OBJS) \
+		$(PYTHON_OBJS) \
+		$(MODULE_OBJS_COMMON) \
+		$(BOOTSTRAP_MODOBJS) \
+		$(srcdir)/Modules/getbuildinfo.c
+	$(CC) -c $(PY_CORE_CFLAGS) $(GETBUILDINFO_CFLAGS) \
+	      -o $@ $(srcdir)/Modules/getbuildinfo.c
+
+GETBUILDINFO_CFLAGS= \
 	      -DGITVERSION="\"`LC_ALL=C $(GITVERSION)`\"" \
 	      -DGITTAG="\"`LC_ALL=C $(GITTAG)`\"" \
-	      -DGITBRANCH="\"`LC_ALL=C $(GITBRANCH)`\"" \
-	      -o $@ $(srcdir)/Modules/getbuildinfo.c
+	      -DGITBRANCH="\"`LC_ALL=C $(GITBRANCH)`\""
 
 Modules/getpath.o: $(srcdir)/Modules/getpath.c Python/frozen_modules/getpath.h Makefile $(PYTHON_HEADERS)
 	$(CC) -c $(PY_CORE_CFLAGS) -DPYTHONPATH='"$(PYTHONPATH)"' \
@@ -2279,7 +2318,7 @@ regen-slots: Python/slots.toml
 	$(PYTHON_FOR_REGEN) $(srcdir)/Tools/build/generate_slots.py \
 		--generate-all
 
-$(LIBRARY_OBJS) $(MODOBJS) Programs/python.o $(PLATFORM_MAIN_OBJS): $(PYTHON_HEADERS)
+$(LIBRARY_OBJS) $(MODOBJS) Modules/config_bootstrap.o Programs/python.o $(PLATFORM_MAIN_OBJS): $(PYTHON_HEADERS)
 
 
 ######################################################################
@@ -3365,7 +3404,7 @@ clean: clean-profile clean-jit-stencils
 clobber: clean
 	-rm -f $(BUILDPYTHON) $(LIBRARY) $(LDLIBRARY) $(DLLLIBRARY) \
 		tags TAGS \
-		config.cache config.log pyconfig.h Modules/config.c
+		config.cache config.log pyconfig.h Modules/config.c Modules/config_bootstrap.c
 	-rm -rf build platform
 	-rm -rf $(PYTHONFRAMEWORKDIR)
 	-rm -rf Platforms/Apple/iOS/Frameworks

Misc/NEWS.d/next/Build/2026-10-25-15-30-00.gh-issue-160689.bootsp.rst

@@ -0,0 +1,5 @@
+The build helper programs ``Programs/_freeze_module`` and
+``_bootstrap_python`` are now linked only with the modules of
+:file:`Modules/Setup.bootstrap`, instead of with every static module. Builtin
+modules added via :file:`Modules/Setup.local` or ``MODULE_BUILDTYPE=static``
+can now depend on frozen modules or on ``getpath``.

Modules/makesetup

@@ -4,17 +4,22 @@ set -e
 # Convert templates into Makefile and config.c, based on the module
 # definitions found in the file Setup.
 #
-# Usage: makesetup [-s dir] [-c file] [-m file] [Setup] ... [-n [Setup] ...]
+# Usage: makesetup [-s dir] [-c file] [-m file] [Setup] ... [-b Setup] ...
+#                  [-n [Setup] ...]
 #
 # Options:
 # -s directory: alternative source directory (default .)
 # -l directory: library source directory (default derived from $0)
 # -c file:      alternative config.c template (default $libdir/config.c.in)
-# -c -:         don't write config.c
+# -c -:         don't write config.c (nor config_bootstrap.c)
 # -m file:      alternative Makefile template (default ./Makefile.pre)
 # -m -:         don't write Makefile
 #
 # Remaining arguments are one or more Setup files (default ./Setup).
+# The Setup file following a -b option holds the *bootstrap* modules:
+# the static modules that the build helper programs (_freeze_module,
+# _bootstrap_python) are linked with. They are also regular modules of
+# the final build.
 # Setup files after a -n option are used for their variables, modules
 # and libraries but not for their .o files.
 #
@@ -28,6 +33,9 @@ set -e
 #   + insert 'extern PyObject* PyInit_<module>(void);' before MARKER 1
 #   + insert '{"<module>", PyInit_<module>},' before MARKER 2
 #
+# Copying config.c.in to config_bootstrap.c (only with a -b Setup file):
+# - same as config.c, but only for the modules of the -b Setup file
+#
 # Copying Makefile.pre to Makefile:
 # - insert an identifying comment at the start
 # - replace _MODBUILT_NAMES_ by the list of *static* and *shared* modules
@@ -37,6 +45,8 @@ set -e
 # - replace _MODOBJS_ by the list of objects from Setup (except for
 #   Setup files after a -n option)
 # - replace _MODLIBS_ by the list of libraries from Setup
+# - replace _BOOTSTRAP_MODOBJS_ and _BOOTSTRAP_MODLIBS_ by the objects and
+#   libraries of the -b Setup file
 # - for each object file mentioned in Setup, append a rule
 #   '<file>.o: <file>.c; <build commands>' to the end of the Makefile
 # - for each module mentioned in Setup, append a rule
@@ -47,13 +57,14 @@ set -e
 # Loop over command line options
 usage='
 usage: makesetup [-s srcdir] [-l libdir] [-c config.c.in] [-m Makefile.pre]
-                 [Setup] ... [-n [Setup] ...]'
+                 [Setup] ... [-b Setup] ... [-n [Setup] ...]'
 srcdir='.'
 libdir=''
 config=''
 makepre=''
 noobjects=''
 doconfig=yes
+bootstrap=
 while :
 do
 	case $1 in
@@ -93,7 +104,8 @@ do
 	echo ''  # Add a linebreak so we don't choke on files missing EOL.
 	case $i in
 	-n)	echo '*noobjects*';;
-	*)	echo '*doconfig*'; cat "$i";;
+	-b)	echo '*bootstrap*';;
+	*)	echo '*doconfig*'; cat "$i"; echo ''; echo '*nobootstrap*';;
 	esac
 done |
 sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
@@ -114,6 +126,10 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 	LIBS=
 	LOCALLIBS=
 	BASELIBS=
+	BOOTMODS=
+	BOOTOBJS=
+	BOOTLIBS=
+	havebootstrap=
 	while read line
 	do
 		# to handle backslashes for sh's that don't automatically
@@ -136,6 +152,8 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 			noobjects=yes;
 			continue;;
 		'*doconfig*')	doconfig=yes; continue;;
+		'*bootstrap*')	bootstrap=yes; havebootstrap=yes; continue;;
+		'*nobootstrap*')	bootstrap=; continue;;
 		'*static*')	doconfig=yes; continue;;
 		'*noconfig*')	doconfig=no; continue;;
 		'*shared*')	doconfig=no; continue;;
@@ -204,6 +222,18 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 				# Detected multiple rules for a module, first rule wins. This
 				# allows users to disable modules in Setup.local.
 				echo 1>&2 "maksetup: '$mod' was handled by previous rule."
+				case $bootstrap in
+				yes)
+					# This module is in the bootstrap Setup file, but an
+					# earlier Setup file (e.g. Setup.local) already defined
+					# it, and that definition won. Give the build helpers
+					# that earlier definition, so they use the same module
+					# as the final interpreter.
+					eval "BOOTMODS=\"\$BOOTMODS \${STATICMOD_$mod}\""
+					eval "BOOTOBJS=\"\$BOOTOBJS \${STATICOBJS_$mod}\""
+					eval "BOOTLIBS=\"\$BOOTLIBS \${STATICLIBS_$mod}\""
+					;;
+				esac
 				continue 2;;
 			esac
 			CONFIGURED="$CONFIGURED,${mod},"
@@ -213,6 +243,12 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 			LIBS="$LIBS $libs"
 			MODS="$MODS $mods"
 			BUILT="$BUILT $mods"
+			case $bootstrap in
+			yes)
+				BOOTLIBS="$BOOTLIBS $libs"
+				BOOTMODS="$BOOTMODS $mods"
+				;;
+			esac
 			;;
 		no)
 			BUILT="$BUILT $mods"
@@ -265,7 +301,21 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 			echo "$rule" >>$rulesf
 		done
 		case $doconfig in
-		yes)	OBJS="$OBJS $objs";;
+		yes)
+			OBJS="$OBJS $objs"
+			case $bootstrap in
+			yes)	BOOTOBJS="$BOOTOBJS $objs";;
+			esac
+			# Record each static module's objects and libs by name, so
+			# the bootstrap handling above can find a definition that
+			# won over a later line in the bootstrap Setup file.
+			for mod in $mods
+			do
+				eval "STATICMOD_$mod='$mod'"
+				eval "STATICOBJS_$mod='$objs'"
+				eval "STATICLIBS_$mod='$libs'"
+			done
+			;;
 		esac
 		for mod in $mods
 		do
@@ -295,24 +345,31 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 	DEFS="BASEMODLIBS=$BASELIBS$NL$DEFS"
 	DEFS="LOCALMODLIBS=$LOCALLIBS$NL$DEFS"
 
-	EXTDECLS=
-	INITBITS=
-	for mod in $MODS
-	do
-		EXTDECLS="${EXTDECLS}extern PyObject* PyInit_$mod(void);$NL"
-		INITBITS="${INITBITS}    {\"$mod\", PyInit_$mod},$NL"
-	done
-
-
-	case $config in
-	-)  ;;
-	*)  sed -e "
+	# Generate a config.c from the template for the given modules
+	genconfig() {
+		out=$1; shift
+		EXTDECLS=
+		INITBITS=
+		for mod
+		do
+			EXTDECLS="${EXTDECLS}extern PyObject* PyInit_$mod(void);$NL"
+			INITBITS="${INITBITS}    {\"$mod\", PyInit_$mod},$NL"
+		done
+		sed -e "
 		1i$NL/* Generated automatically from $config by makesetup. */
 		/MARKER 1/i$NL$EXTDECLS
 
 		/MARKER 2/i$NL$INITBITS
 
-		" $config >config.c
+		" $config >$out
+	}
+
+	case $config in
+	-)  ;;
+	*)  genconfig config.c $MODS
+	    case $havebootstrap in
+	    yes)  genconfig config_bootstrap.c $BOOTMODS;;
+	    esac
 	    ;;
 	esac
 
@@ -331,6 +388,9 @@ sed -e 's/[ 	]*#.*//' -e '/^[ 	]*$/d' |
 		echo "s%_MODBUILT_NAMES_%$BUILT%" >>$sedf
 		echo "s%_MODSHARED_NAMES_%$BUILT_SHARED%" >>$sedf
 		echo "s%_MODDISABLED_NAMES_%$DISABLED%" >>$sedf
+		# _BOOTSTRAP_* first: _MODOBJS_ is a substring of _BOOTSTRAP_MODOBJS_
+		echo "s%_BOOTSTRAP_MODOBJS_%$BOOTOBJS%" >>$sedf
+		echo "s%_BOOTSTRAP_MODLIBS_%$BOOTLIBS%" >>$sedf
 		echo "s%_MODOBJS_%$OBJS%" >>$sedf
 		echo "s%_MODLIBS_%$LIBS%" >>$sedf
 		echo "/Definitions added by makesetup/r $sedr" >>$sedf

Tools/c-analyzer/cpython/ignored.tsv

@@ -314,6 +314,7 @@ Modules/cmathmodule.c	-	sinh_special_values	-
 Modules/cmathmodule.c	-	sqrt_special_values	-
 Modules/cmathmodule.c	-	tanh_special_values	-
 Modules/config.c	-	_PyImport_Inittab	-
+Modules/config_bootstrap.c	-	_PyImport_Inittab	-
 Modules/faulthandler.c	-	faulthandler_handlers	-
 Modules/getnameinfo.c	-	gni_afdl	-
 Modules/hmacmodule.c	-	py_hmac_static_hinfo	-

configure

@@ -40684,12 +40684,12 @@ fi
 printf "%s\n" "$as_me: creating Makefile" >&6;}
 $SHELL $srcdir/Modules/makesetup -c $srcdir/Modules/config.c.in \
 			-s Modules \
-			Modules/Setup.local Modules/Setup.stdlib Modules/Setup.bootstrap $srcdir/Modules/Setup
+			Modules/Setup.local Modules/Setup.stdlib -b Modules/Setup.bootstrap $srcdir/Modules/Setup
 if test $? -ne 0; then
   as_fn_error $? "makesetup failed" "$LINENO" 5
 fi
 
-mv config.c Modules
+mv config.c config_bootstrap.c Modules
 
 if test -z "$PKG_CONFIG"; then
   { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: pkg-config is missing. Some dependencies may not be detected correctly." >&5

configure.ac

@@ -9070,12 +9070,12 @@ fi
 AC_MSG_NOTICE([creating Makefile])
 $SHELL $srcdir/Modules/makesetup -c $srcdir/Modules/config.c.in \
 			-s Modules \
-			Modules/Setup.local Modules/Setup.stdlib Modules/Setup.bootstrap $srcdir/Modules/Setup
+			Modules/Setup.local Modules/Setup.stdlib -b Modules/Setup.bootstrap $srcdir/Modules/Setup
 if test $? -ne 0; then
   AC_MSG_ERROR([makesetup failed])
 fi
 
-mv config.c Modules
+mv config.c config_bootstrap.c Modules
 
 if test -z "$PKG_CONFIG"; then
   AC_MSG_WARN([pkg-config is missing. Some dependencies may not be detected correctly.])