maint.mk: prohibit definition of symbols defined by gnulib

* top/maint.mk (sc_prohibit_always-defined_macros): Reject the
definition of symbols defined by gnulib.

diff --git a/ChangeLog b/ChangeLog
index 7c1f4e210cce7ce0966c72deada8516aba0aa6b5..4de7bb32d2df90afc3da241f607a896823f65772 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2010-05-09  Jim Meyering  <meyering@redhat.com>
+
+       maint.mk: prohibit definition of symbols defined by gnulib
+       * top/maint.mk (sc_prohibit_always-defined_macros): Reject the
+       definition of symbols defined by gnulib.
+
 2010-05-09  Bruno Haible  <bruno@clisp.org>
 
        acl: Avoid test failure on Cygwin-hosted mingw.

diff --git a/top/maint.mk b/top/maint.mk
index 335d078358eff776deb759c75f9d5691bdc73db6..8d3d137d8fdbd59cd4ac4844bb6079b5b88c01aa 100644 (file)
--- a/top/maint.mk
+++ b/top/maint.mk
@@ -665,6 +665,50 @@ sc_prohibit_always_true_header_tests:
 '  with the corresponding gnulib module, they are always true'         \
          $(_sc_search_regexp)
 
+# ==================================================================
+gl_other_headers_ ?= \
+  intprops.h   \
+  openat.h     \
+  stat-macros.h
+
+# Perl -lne code to extract "significant" cpp-defined symbols from a
+# gnulib header file, eliminating a few common false-positives.
+gl_extract_significant_defines_ = \
+  /^\# *define ([^_ (][^ (]*)(\s*\(|\s+\w+)/ && $$2 !~ /(?:rpl_|_used_without_)/\
+    and print $$1
+
+# Create a list of regular expressions matching the names
+# of macros that are guaranteed to be defined by parts of gnulib.
+.re-defmac:
+       @gen_h=$(gl_generated_headers_);                                \
+       (cd $(gnulib_dir)/lib;                                          \
+         for f in *.in.h $(gl_other_headers_); do                      \
+           perl -lne '$(gl_extract_significant_defines_)' $$f;         \
+         done;                                                         \
+       ) | sort -u                                                     \
+         | grep -Ev '^ATTRIBUTE_NORETURN'                              \
+         | sed 's/^/^ *# *define /;s/$$/\\>/'                          \
+         > $@-t
+       @mv $@-t $@
+
+define gl_trap_
+  Exit () { set +e; (exit $$1); exit $$1; };                           \
+  for sig in 1 2 3 13 15; do                                           \
+    eval "trap 'Exit $$(expr $$sig + 128)' $$sig";                     \
+  done
+endef
+
+# Don't define macros that we already get from gnulib header files.
+sc_prohibit_always-defined_macros: .re-defmac
+       @if test -d $(gnulib_dir); then                                 \
+         trap 'rc=$$?; rm -f .re-defmac; exit $$rc' 0;                 \
+         $(gl_trap_);                                                  \
+         grep -f .re-defmac $$($(VC_LIST_EXCEPT))                      \
+           && { echo '$(ME): define the above via some gnulib .h file' \
+                 1>&2;  exit 1; } || :;                                \
+       fi
+# ==================================================================
+
 # Prohibit checked in backup files.
 sc_prohibit_backup_files:
        @$(VC_LIST) | grep '~$$' &&                             \