Re: PATCH: improve ATTRIBUTE_GCC_DIAG

[Ben Elliston <bje at au1 dot ibm dot com>]

Here is another iteration.  This works well with a range of build
compilers.   Tested with and without --enable-checking=no.  Okay for the
trunk?

2009-05-22  Ben Elliston  <bje@au.ibm.com>

        * Makefile.in (bversion.h, s-bversion): New targets.
        (TOPLEV_H): Add bversion.h.
        * toplev.h: Include "bversion.h".
        (ATTRIBUTE_GCC_DIAG): When building with checking disabled, use
        the __format__ attribute only if compiling with the same version
        of GCC as the sources (the "build version").

Index: Makefile.in
===================================================================
--- Makefile.in (revision 147790)
+++ Makefile.in (working copy)
@@ -792,7 +792,7 @@
 
 # Shorthand variables for dependency lists.
 EXCEPT_H = except.h sbitmap.h vecprim.h
-TOPLEV_H = toplev.h input.h
+TOPLEV_H = toplev.h input.h bversion.h
 TARGET_H = $(TM_H) target.h insn-modes.h
 MACHMODE_H = machmode.h mode-classes.def insn-modes.h
 HOOKS_H = hooks.h $(MACHMODE_H)
@@ -2455,6 +2455,14 @@
    $(MACHMODE_H) $(TARGET_DEF_H) $(TARGET_H) $(GGC_H) gt-targhooks.h \
    $(OPTABS_H) $(RECOG_H) reload.h
 
+bversion.h: s-bversion; @true
+s-bversion: BASE-VER
+       echo "#define BUILDING_GCC_MAJOR `echo $(BASEVER_c) | sed -e 's/^\([0-9]*\).*$$/\1/'`" > bversion.h
+       echo "#define BUILDING_GCC_MINOR `echo $(BASEVER_c) | sed -e 's/^[0-9]*\.\([0-9]*\).*$$/\1/'`" >> bversion.h
+       echo "#define BUILDING_GCC_PATCHLEVEL `echo $(BASEVER_c) | sed -e 's/^[0-9]*\.[0-9]*\.\([0-9]*\)$$/\1/'`" >> bversion.h
+       echo "#define BUILDING_GCC_VERSION (BUILDING_GCC_MAJOR * 1000 + BUILDING_GCC_MINOR)" >> bversion.h
+       $(STAMP) s-bversion
+
 toplev.o : toplev.c $(CONFIG_H) $(SYSTEM_H) coretypes.h $(TM_H) $(TREE_H) \
    version.h $(RTL_H) $(FUNCTION_H) $(FLAGS_H) xcoffout.h $(INPUT_H) \
    $(INSN_ATTR_H) output.h $(DIAGNOSTIC_H) debug.h insn-config.h intl.h \
Index: toplev.h
===================================================================
--- toplev.h    (revision 147790)
+++ toplev.h    (working copy)
@@ -21,6 +21,7 @@
 #ifndef GCC_TOPLEV_H
 #define GCC_TOPLEV_H
 #include "input.h"
+#include "bversion.h"
 
 /* If non-NULL, return one past-the-end of the matching SUBPART of
    the WHOLE string.  */
@@ -49,7 +50,7 @@
 /* None of these functions are suitable for ATTRIBUTE_PRINTF, because
    each language front end can extend them with its own set of format
    specifiers.  We must use custom format checks.  */
-#if GCC_VERSION >= 4001
+#if (ENABLE_CHECKING && GCC_VERSION >= 4001) || GCC_VERSION == BUILDING_GCC_VERSION
 #define ATTRIBUTE_GCC_DIAG(m, n) __attribute__ ((__format__ (GCC_DIAG_STYLE, m, n))) ATTRIBUTE_NONNULL(m)
 #else
 #define ATTRIBUTE_GCC_DIAG(m, n) ATTRIBUTE_NONNULL(m)