[toplevel] Add --enable-bootstrap configure switch

[Paolo Bonzini <bonzini at gnu dot org>]

This patch completes the change introduced by the previous
maybe-deps patch, and is the real reason why I wanted to do
that.

It provides a --enable-bootstrap configure switch that will
enable toplevel bootstrapping: when it is used, make all
actually behaves like a "make bubblestrap".  gcc-directory
bootstrapping of course requires --disable-bootstrap: indeed
the two rule bodies for old vs. new-style bootstrapping are
now mutually exclusive in the Makefile.

The default is --disable-bootstrap until toplevel bootstrapping
becomes the default, then it will depend on build==host==target.

Old-bootstrapped and new-bootstrapped i686-pc-linux-gnu,
ok for mainline and src?

Paolo
2004-05-24  Paolo Bonzini  <bonzini@gnu.org>

	* Makefile.tpl (all.normal): Rename to all.
	(all): Replace with a rule to pick the default
	target from configure.
	(all-gcc, configure-gcc): Use conditionals to
	do nothing when toplevel bootstrap is going on.
	(GCC old-style bootstrap) [gcc-bootstrap]: Disable.
	(GCC new-style bootstrap) [gcc-no-bootstrap]: Disable.
	* Makefile.in: Regenerate.
	* configure.in: Support --enable-bootstrap.
	* configure: Regenerate.

Index: Makefile.tpl
===================================================================
RCS file: /cvs/gcc/gcc/Makefile.tpl,v
retrieving revision 1.99
diff -u -r1.99 Makefile.tpl
--- Makefile.tpl	24 May 2004 11:08:12 -0000	1.99
+++ Makefile.tpl	24 May 2004 11:12:44 -0000
@@ -387,8 +387,7 @@
 
 # The first rule in the file had better be this one.  Don't put any above it.
 # This lives here to allow makefile fragments to contain dependencies.
-all: all.normal
-.PHONY: all
+@default_target@:
 
 #### host and target specific makefile fragments come in here.
 @target_makefile_frag@
@@ -493,9 +492,9 @@
     maybe-configure-target-[+module+][+
   ENDFOR target_modules +]
 
-# The target built for a native build.
-.PHONY: all.normal
-all.normal: @all_build_modules@ all-host all-target
+# The target built for a native non-bootstrap build.
+.PHONY: all
+all: @all_build_modules@ all-host all-target
 
 .PHONY: all-host
 all-host: maybe-all-gcc [+
@@ -1106,8 +1105,9 @@
 @if gcc
 maybe-configure-gcc: configure-gcc
 configure-gcc:
+@endif gcc
+@if gcc-no-bootstrap
 	@test ! -f gcc/Makefile || exit 0; \
-	[ -f stage_last ] && exit 0; \
 	[ -d gcc ] || mkdir gcc; \
 	r=`${PWD_COMMAND}`; export r; \
 	s=`cd $(srcdir); ${PWD_COMMAND}`; export s; \
@@ -1146,7 +1146,7 @@
 	$(SHELL) $${libsrcdir}/configure \
 	  $(HOST_CONFIGARGS) $${srcdiroption} \
 	  || exit 1
-@endif gcc
+@endif gcc-no-bootstrap
 
 # Don't 'make all' in gcc if it's already been made by 'bootstrap'; that
 # causes trouble.  This wart will be fixed eventually by moving
@@ -1156,18 +1156,17 @@
 @if gcc
 maybe-all-gcc: all-gcc
 all-gcc: configure-gcc
+@endif gcc
+@if gcc-no-bootstrap
 	r=`${PWD_COMMAND}`; export r; \
 	s=`cd $(srcdir); ${PWD_COMMAND}`; export s; \
-	if [ -f stage_last ] ; then \
-	  true ; \
-	elif [ -f gcc/stage_last ] ; then \
+	if [ -f gcc/stage_last ] ; then \
 	  $(SET_LIB_PATH) \
 	  (cd gcc && $(MAKE) $(GCC_FLAGS_TO_PASS) quickstrap); \
 	else \
 	  $(SET_LIB_PATH) \
 	  (cd gcc && $(MAKE) $(GCC_FLAGS_TO_PASS) all); \
 	fi
-@endif gcc
 
 # Building GCC uses some tools for rebuilding "source" files
 # like texinfo, bison/byacc, etc.  So we must depend on those.
@@ -1242,6 +1241,7 @@
 	echo "Building runtime libraries"; \
 	$(MAKE) $(BASE_FLAGS_TO_PASS) $(RECURSE_FLAGS) \
 	  LANGUAGES="c c++" all
+@endif gcc-no-bootstrap
 
 .PHONY: check-gcc maybe-check-gcc
 maybe-check-gcc:
@@ -1337,6 +1337,7 @@
 
 [+ ENDFOR recursive_targets +]
 
+@if gcc-bootstrap
 # ---------------------
 # GCC bootstrap support
 # ---------------------
@@ -1545,6 +1546,7 @@
 [+ ENDIF cleanstrap-target +]
 
 [+ ENDFOR bootstrap-stage +]
+@endif gcc-bootstrap
 
 # --------------------------------------
 # Dependencies between different modules
Index: configure.in
===================================================================
RCS file: /cvs/gcc/gcc/configure.in,v
retrieving revision 1.290
diff -u -r1.290 configure.in
--- configure.in	24 May 2004 11:08:12 -0000	1.290
+++ configure.in	24 May 2004 11:12:44 -0000
@@ -1760,6 +1760,36 @@
 /^@if target-$module\$/d
 /^@endif target-$module\$/d"
 done
+
+AC_ARG_ENABLE([bootstrap],
+[  --enable-bootstrap     Enable bootstrapping [no]],,
+enable_bootstrap=no)
+if test -d ${srcdir}/gcc; then
+  case "$host:$target:$enable_bootstrap" in
+    $build:$build:yes | *:no) ;;
+    *:yes) AC_MSG_ERROR([cannot bootstrap a cross-compiler]) ;;
+    *) AC_MSG_ERROR([invalid option for --enable-bootstrap]) ;;
+  esac
+else
+  if test $enable_bootstrap = yes; then
+    AC_MSG_ERROR([cannot bootstrap without a compiler])
+  fi
+fi
+
+case "$enable_bootstrap" in
+  yes)
+    default_target=new-bootstrap
+    extrasub="$extrasub
+/^@if gcc-bootstrap\$/d
+/^@endif gcc-bootstrap\$/d" ;;
+  no)
+    default_target=all
+    extrasub="$extrasub
+/^@if gcc-no-bootstrap\$/d
+/^@endif gcc-no-bootstrap\$/d" ;;
+esac
+AC_SUBST(default_target)
+
 extrasub="$extrasub
 /^@if /,/^@endif /d"