[Automake-ng] [PATCH 2/2] built sources, config.h: rely on order-only prerequisites

[Stefano Lattarini]

This approach avoids some extra make recursions, and makes the code a
little clearer.  It cannot be used in mainline automake because order-only
prerequisites are supported only by GNU make.

* lib/am/install.am (install): Use order-only prerequisites (rather than
the hacky automake-time substitution '%maybe_BUILT_SOURCES%') to enforce
$(BUILT_SOURCES) being built before the targets 'install-recursive' and
'install-am'.
* automake.in (handle_install): Don't do the '%maybe_BUILT_SOURCES%'
substitution anymore.
(do_check_merge_target, handle_all): Use order-only prerequisites to
enforce $(BUILT_SOURCES) being built before the targets 'check-am',
'all-am', 'check-recursive' and 'all-recursive' targets.
(generate_makefile): Use 'set_seen' to mark the $(BUILT_SOURCES) variable
as "already analyzed", to let Automake know it shouldn't expect to have
to deal with a program named 'BUILT' when a definition of that variable is
seen.
* t/built-sources-check.sh: Remove obsolete grepping check.

Signed-off-by: Stefano Lattarini <address@hidden>
---
 automake.in              |   50 +++++++++++++++-------------------------------
 lib/am/install.am        |    8 ++++++--
 t/built-sources-check.sh |    5 -----
 3 files changed, 22 insertions(+), 41 deletions(-)

diff --git a/automake.in b/automake.in
index 7af3fec..158dc9e 100644
--- a/automake.in
+++ b/automake.in
@@ -4419,10 +4419,6 @@ sub handle_install ()
   $output_rules .= &file_contents
     ('install',
      new Automake::Location,
-     maybe_BUILT_SOURCES => (set_seen ('BUILT_SOURCES')
-                            ? (" \$(BUILT_SOURCES)\n"
-                               . "\t\$(MAKE)")
-                            : ''),
      'installdirs-local' => (user_phony_rule 'installdirs-local'
                             ? ' installdirs-local' : ''),
      am__installdirs => variable_value ('am__installdirs') || '');
@@ -4455,37 +4451,21 @@ sub handle_all ($)
     &pretty_print_rule ("all-am:", "\t\t", @all);
     &depend ('.PHONY', 'all-am', 'all');
 
-
-    # Output 'all'.
-
+    # Output 'all:'.
     my @local_headers = ();
-    push @local_headers, '$(BUILT_SOURCES)'
-      if var ('BUILT_SOURCES');
     foreach my $spec (@config_headers)
       {
        my ($out, @ins) = split_config_file_spec ($spec);
        push @local_headers, basename ($out)
          if dirname ($out) eq $relative_dir;
       }
-
-    if (@local_headers)
-      {
-       # We need to make sure config.h is built before we recurse.
-       # We also want to make sure that built sources are built
-       # before any ordinary 'all' targets are run.  We can't do this
-       # by changing the order of dependencies to the "all" because
-       # that breaks when using parallel makes.  Instead we handle
-       # things explicitly.
-       $output_all .= ("all: @local_headers"
-                       . "\n\t\$(MAKE) "
-                       . (var ('SUBDIRS') ? 'all-recursive' : 'all-am')
-                       . "\n\n");
-      }
-    else
-      {
-       $output_all .= "all: " . (var ('SUBDIRS')
-                                 ? 'all-recursive' : 'all-am') . "\n\n";
-      }
+    # We need to make sure config.h is built before we recurse.
+    # We also want to make sure that built sources are built
+    # before any ordinary 'all' targets are run.
+    my $deps = var ('SUBDIRS') ? 'all-recursive' : 'all-am';
+    $output_all .= "all: $deps\n" .
+                   "$deps: | \$(BUILT_SOURCES) @local_headers\n" .
+                   "\n";
 }
 
 
@@ -4514,12 +4494,9 @@ sub do_check_merge_target ()
 
   depend '.PHONY', 'check', 'check-am';
   # Handle recursion.  We have to honor BUILT_SOURCES like for 'all:'.
-  $output_rules .= ("check: "
-                   . (var ('BUILT_SOURCES')
-                      ? "\$(BUILT_SOURCES)\n\t\$(MAKE) "
-                      : '')
-                   . (var ('SUBDIRS') ? 'check-recursive' : 'check-am')
-                   . "\n");
+  my $deps = var ('SUBDIRS') ? 'check-recursive' : 'check-am';
+  $output_rules .= "check: $deps\n" .
+                   "$deps: | \$(BUILT_SOURCES)\n";
 }
 
 # handle_clean ($MAKEFILE)
@@ -7913,6 +7890,11 @@ sub generate_makefile ($$)
   check_gnu_standards;
   check_gnits_standards;
 
+  # Let Automake know it shouldn't expect to have to deal with a
+  # program named 'BUILT' when the $(BUILT_SOURCES) variable is
+  # seen, by marking that variable as "already analyzed".
+  set_seen 'BUILT_SOURCES';
+
   handle_configure ($makefile_am, $makefile_in, $makefile, @inputs);
   handle_gettext;
   handle_libraries;
diff --git a/lib/am/install.am b/lib/am/install.am
index ec7aa52..fbbe181 100644
--- a/lib/am/install.am
+++ b/lib/am/install.am
@@ -51,12 +51,16 @@ endif !%?SUBDIRS%
 if %?SUBDIRS%
 RECURSIVE_TARGETS += install-data-recursive install-exec-recursive \
                     install-recursive uninstall-recursive
-install:%maybe_BUILT_SOURCES% install-recursive
+install: install-recursive
+install-recursive: | $(BUILT_SOURCES)
 install-exec: install-exec-recursive
 install-data: install-data-recursive
 uninstall: uninstall-recursive
 else !%?SUBDIRS%
-install:%maybe_BUILT_SOURCES% install-am
+install: install-am
+# FIXME: Hack so that Automake won't lose the 'install-am' recipe below.
+# FIXME: We definitely need to make the automake parser smarter ...
+install$(am__empty)-am: | $(BUILT_SOURCES)
 install-exec: install-exec-am
 install-data: install-data-am
 uninstall: uninstall-am
diff --git a/t/built-sources-check.sh b/t/built-sources-check.sh
index 90c841f..27b1fbc 100755
--- a/t/built-sources-check.sh
+++ b/t/built-sources-check.sh
@@ -62,11 +62,6 @@ cat stdout
 grep '^PASS: subrun\.sh *$' stdout
 grep 'PASS.*echo\.sh' stdout && Exit 1
 
-# check should depend directly on $(BUILT_SOURCES) (similar tests
-# are in check.test and check2.test).
-$EGREP '^check:.* \$\(BUILT_SOURCES\)( |$)' Makefile.in
-$EGREP '^check:.* \$\(BUILT_SOURCES\)( |$)' dir/Makefile.in
-
 $MAKE distcheck
 
 :
-- 
1.7.9.5