bpo-44009: Provide "python3.x-intel64" for Apple Silicon Macs (GH-25804)

This allows reliably forcing macOS universal2 framework builds
to run under Rosetta 2 Intel-64 emulation on Apple Silicon Macs
if needed for testing or when universal2 wheels are not yet
available.

Author: ned-deily

Mac/Makefile.in

@@ -20,6 +20,7 @@ FRAMEWORKUNIXTOOLSPREFIX=@FRAMEWORKUNIXTOOLSPREFIX@
 PYTHONFRAMEWORK=@PYTHONFRAMEWORK@
 PYTHONFRAMEWORKIDENTIFIER=@PYTHONFRAMEWORKIDENTIFIER@
 LIPO_32BIT_FLAGS=@LIPO_32BIT_FLAGS@
+LIPO_INTEL64_FLAGS=@LIPO_INTEL64_FLAGS@
 CC=@CC@
 MACOSX_DEPLOYMENT_TARGET=@CONFIGURE_MACOSX_DEPLOYMENT_TARGET@
 export MACOSX_DEPLOYMENT_TARGET
@@ -92,6 +93,16 @@ installunixtools:
 			$(LN) -s $(BINDIR)/$${fn} $${fn} ;\
 		done ;\
 	fi
+	-if test "x$(LIPO_INTEL64_FLAGS)" != "x"; then \
+		cd "$(DESTDIR)$(FRAMEWORKUNIXTOOLSPREFIX)/bin" && \
+		for fn in \
+				python3-intel64 \
+				; \
+		do \
+			rm -f $${fn} ;\
+			$(LN) -s $(BINDIR)/$${fn} $${fn} ;\
+		done ;\
+	fi
 	-if test "x$(ENSUREPIP)" != "xno"  ; then \
 		cd "$(DESTDIR)$(FRAMEWORKUNIXTOOLSPREFIX)/bin" && \
 		for fn in \
@@ -142,6 +153,16 @@ altinstallunixtools:
 			$(LN) -s $(BINDIR)/$${fn} $${fn} ;\
 		done ;\
 	fi
+	-if test "x$(LIPO_INTEL64_FLAGS)" != "x"; then \
+		cd "$(DESTDIR)$(FRAMEWORKUNIXTOOLSPREFIX)/bin" && \
+		for fn in \
+				python$(VERSION)-intel64 \
+				; \
+		do \
+			rm -f $${fn} ;\
+			$(LN) -s $(BINDIR)/$${fn} $${fn} ;\
+		done ;\
+	fi
 	-if test "x$(ENSUREPIP)" != "xno"  ; then \
 		cd "$(DESTDIR)$(FRAMEWORKUNIXTOOLSPREFIX)/bin" && \
 		for fn in \

Mac/README.rst

@@ -162,6 +162,9 @@ following combinations of SDKs and universal-archs flavors are available:
 The makefile for a framework build will also install ``python3.x-32``
 binaries when the universal architecture includes at least one 32-bit
 architecture (that is, for all flavors but ``64-bit`` and ``intel-64``).
+It will also install ``python3.x-intel64`` binaries in the ``universal2``
+case to allow easy execution with the Rosetta 2 Intel emulator on Apple
+Silicon Macs.
 
 Running a specific architecture
 ...............................
@@ -181,6 +184,9 @@ subprocesses also run in 32-bit-mode if the main interpreter does, use
 a ``python3.x-32`` binary and use the value of ``sys.executable`` as the
 ``subprocess`` ``Popen`` executable value.
 
+Likewise, use ``python3.x-intel64`` to force execution in ``x86_64`` mode
+with ``universal2`` binaries.
+
 Building and using a framework-based Python on macOS
 ====================================================
 

Makefile.pre.in

@@ -189,6 +189,9 @@ STRIPFLAG=-s
 # Flags to lipo to produce a 32-bit-only universal executable
 LIPO_32BIT_FLAGS=@LIPO_32BIT_FLAGS@
 
+# Flags to lipo to produce an intel-64-only universal executable
+LIPO_INTEL64_FLAGS=@LIPO_INTEL64_FLAGS@
+
 # Options to enable prebinding (for fast startup prior to Mac OS X 10.3)
 OTHER_LIBTOOL_OPT=@OTHER_LIBTOOL_OPT@
 
@@ -1344,6 +1347,12 @@ altbininstall: $(BUILDPYTHON) @FRAMEWORKPYTHONW@
 			-output $(DESTDIR)$(BINDIR)/python$(VERSION)-32$(EXE) \
 			$(DESTDIR)$(BINDIR)/python$(VERSION)$(EXE); \
 	fi
+	if test "x$(LIPO_INTEL64_FLAGS)" != "x" ; then \
+		rm -f $(DESTDIR)$(BINDIR)python$(VERSION)-intel64$(EXE); \
+		lipo $(LIPO_INTEL64_FLAGS) \
+			-output $(DESTDIR)$(BINDIR)/python$(VERSION)-intel64$(EXE) \
+			$(DESTDIR)$(BINDIR)/python$(VERSION)$(EXE); \
+	fi
 
 bininstall: altbininstall
 	if test ! -d $(DESTDIR)$(LIBPC); then \
@@ -1379,6 +1388,10 @@ bininstall: altbininstall
 		rm -f $(DESTDIR)$(BINDIR)/python3-32$(EXE); \
 		(cd $(DESTDIR)$(BINDIR); $(LN) -s python$(VERSION)-32$(EXE) python3-32$(EXE)) \
 	fi
+	if test "x$(LIPO_INTEL64_FLAGS)" != "x" ; then \
+		rm -f $(DESTDIR)$(BINDIR)/python3-intel64$(EXE); \
+		(cd $(DESTDIR)$(BINDIR); $(LN) -s python$(VERSION)-intel64$(EXE) python3-intel64$(EXE)) \
+	fi
 
 # Install the versioned manual page
 altmaninstall:

Misc/NEWS.d/next/macOS/2021-05-02-03-45-30.bpo-44009.uvhmlh.rst

@@ -0,0 +1,4 @@
+Provide "python3.x-intel64" executable to allow reliably forcing macOS
+universal2 framework builds to run under Rosetta 2 Intel-64 emulation on
+Apple Silicon Macs.  This can be useful for testing or when universal2
+wheels are not yet available.

configure

@@ -752,6 +752,7 @@ PYTHONFRAMEWORKPREFIX
 PYTHONFRAMEWORKDIR
 PYTHONFRAMEWORKIDENTIFIER
 PYTHONFRAMEWORK
+LIPO_INTEL64_FLAGS
 LIPO_32BIT_FLAGS
 ARCH_RUN_32BIT
 UNIVERSALSDK
@@ -1519,11 +1520,12 @@ Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
   --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
   --with-universal-archs=ARCH
-                          specify the kind of universal binary that should be
-                          created. this option is only valid when
+                          specify the kind of macOS universal binary that
+                          should be created. This option is only valid when
                           --enable-universalsdk is set; options are:
-                          ("universal2", "32-bit", "64-bit", "3-way", "intel",
-                          "intel-32", "intel-64", or "all") see Mac/README.rst
+                          ("universal2", "intel-64", "intel-32", "intel",
+                          "32-bit", "64-bit", "3-way", or "all") see
+                          Mac/README.rst
   --with-framework-name=FRAMEWORK
                           specify the name for the python framework on macOS
                           only valid when --enable-framework is set. see
@@ -3139,6 +3141,7 @@ then
 fi
 
 
+
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for --with-universal-archs" >&5
 $as_echo_n "checking for --with-universal-archs... " >&6; }
 
@@ -7522,6 +7525,7 @@ $as_echo_n "checking which compiler should be used... " >&6; }
 $as_echo "$CC" >&6; }
         fi
 
+        LIPO_INTEL64_FLAGS=""
         if test "${enable_universalsdk}"
         then
             case "$UNIVERSAL_ARCHS" in
@@ -7543,8 +7547,9 @@ $as_echo "$CC" >&6; }
             universal2)
                UNIVERSAL_ARCH_FLAGS="-arch arm64 -arch x86_64"
                LIPO_32BIT_FLAGS=""
+               LIPO_INTEL64_FLAGS="-extract x86_64"
                ARCH_RUN_32BIT="true"
-		;;
+               ;;
             intel)
                UNIVERSAL_ARCH_FLAGS="-arch i386 -arch x86_64"
                LIPO_32BIT_FLAGS="-extract i386"

configure.ac

@@ -220,12 +220,14 @@ then
 fi
 
 AC_SUBST(LIPO_32BIT_FLAGS)
+AC_SUBST(LIPO_INTEL64_FLAGS)
 AC_MSG_CHECKING(for --with-universal-archs)
 AC_ARG_WITH(universal-archs,
     AS_HELP_STRING([--with-universal-archs=ARCH],
-                   [specify the kind of universal binary that should be created. this option is
-                    only valid when --enable-universalsdk is set; options are:
-                    ("universal2", "32-bit", "64-bit", "3-way", "intel", "intel-32", "intel-64", or "all")
+                   [specify the kind of macOS universal binary that should be created.
+                    This option is only valid when --enable-universalsdk is set; options are:
+                    ("universal2", "intel-64", "intel-32", "intel", "32-bit",
+                    "64-bit", "3-way", or "all")
                     see Mac/README.rst]),
 [
 	UNIVERSAL_ARCHS="$withval"
@@ -1874,6 +1876,7 @@ yes)
             AC_MSG_RESULT($CC)
         fi
 
+        LIPO_INTEL64_FLAGS=""
         if test "${enable_universalsdk}"
         then
             case "$UNIVERSAL_ARCHS" in
@@ -1895,8 +1898,9 @@ yes)
             universal2)
                UNIVERSAL_ARCH_FLAGS="-arch arm64 -arch x86_64"
                LIPO_32BIT_FLAGS=""
+               LIPO_INTEL64_FLAGS="-extract x86_64"
                ARCH_RUN_32BIT="true"
-		;;
+               ;;
             intel)
                UNIVERSAL_ARCH_FLAGS="-arch i386 -arch x86_64"
                LIPO_32BIT_FLAGS="-extract i386"