sim: sync build_warnings handling with gdb

The sim code gets the logic for SIM_AC_OPTION_WARNINGS from gdb, but
it hasn't been updated in a good long while.  Sync with the latest
gdb code.

There is a sim specific change in here: we disable -Werror for now.
This is because all sim code atm contains warnings.  Will probably
have to slowly add a white list of targets which can tolerate this
until everyone is updated.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

sim/common/ChangeLog

@@ -1,3 +1,9 @@
+2012-03-22  Mike Frysinger  <vapier@gentoo.org>
+
+	* acinclude.m4 (SIM_AC_OPTION_WARNINGS): Copy AC_ARG_ENABLE(werror),
+	WERROR_CFLAGS, and build_warnings from gdb/configure.ac.  Comment
+	out -Werror initialization.
+
 2012-03-19  Mike Frysinger  <vapier@gentoo.org>
 
 	* Make-common.in (TAGS): Change a-z to [:lower:].

sim/common/acinclude.m4

@@ -816,31 +816,44 @@ dnl --enable-build-warnings is for developers of the simulator.
 dnl it enables extra GCC specific warnings.
 AC_DEFUN([SIM_AC_OPTION_WARNINGS],
 [
-# NOTE: Don't add -Wall or -Wunused, they both include
+AC_ARG_ENABLE(werror,
-# -Wunused-parameter which reports bogus warnings.
+  AS_HELP_STRING([--enable-werror], [treat compile warnings as errors]),
-# NOTE: If you add to this list, remember to update
+  [case "${enableval}" in
-# gdb/doc/gdbint.texinfo.
+     yes | y) ERROR_ON_WARNING="yes" ;;
-build_warnings="-Wimplicit -Wreturn-type -Wcomment -Wtrigraphs \
+     no | n)  ERROR_ON_WARNING="no" ;;
--Wformat -Wparentheses -Wpointer-arith"
+     *) AC_MSG_ERROR(bad value ${enableval} for --enable-werror) ;;
-# GCC supports -Wuninitialized only with -O or -On, n != 0.
+   esac])
-if test x${CFLAGS+set} = xset; then
+
-  case "${CFLAGS}" in
+# Enable -Werror by default when using gcc
-    *"-O0"* ) ;;
+if test "${GCC}" = yes -a -z "${ERROR_ON_WARNING}" ; then
-    *"-O"* )
+    ERROR_ON_WARNING=yes
-      build_warnings="${build_warnings} -Wuninitialized"
-    ;;
-  esac
-else
-  build_warnings="${build_warnings} -Wuninitialized"
 fi
-# Up for debate: -Wswitch -Wcomment -trigraphs -Wtrigraphs
+
-# -Wunused-function -Wunused-label -Wunused-variable -Wunused-value
+WERROR_CFLAGS=""
-# -Wchar-subscripts -Wtraditional -Wshadow -Wcast-qual
+if test "${ERROR_ON_WARNING}" = yes ; then
-# -Wcast-align -Wwrite-strings -Wconversion -Wstrict-prototypes
+# NOTE: Disabled in the sim dir due to most sims generating warnings.
-# -Wmissing-prototypes -Wmissing-declarations -Wredundant-decls
+#    WERROR_CFLAGS="-Werror"
-# -Woverloaded-virtual -Winline -Werror"
+     true
+fi
+
+# The entries after -Wno-pointer-sign are disabled warnings which may
+# be enabled in the future, which can not currently be used to build
+# GDB.
+# NOTE: If you change this list, remember to update
+# gdb/doc/gdbint.texinfo.
+build_warnings="-Wall -Wdeclaration-after-statement -Wpointer-arith \
+-Wformat-nonliteral -Wno-pointer-sign \
+-Wno-unused -Wunused-value -Wunused-function \
+-Wno-switch -Wno-char-subscripts -Wmissing-prototypes"
+
+# Enable -Wno-format by default when using gcc on mingw since many
+# GCC versions complain about %I64.
+case "${host}" in
+  *-*-mingw32*) build_warnings="$build_warnings -Wno-format" ;;
+esac
+
 AC_ARG_ENABLE(build-warnings,
-[  --enable-build-warnings Enable build-time compiler warnings if gcc is used],
+AS_HELP_STRING([--enable-build-warnings], [enable build-time compiler warnings if gcc is used]),
 [case "${enableval}" in
   yes)	;;
   no)	build_warnings="-w";;
@@ -854,7 +867,7 @@ if test x"$silent" != x"yes" && test x"$build_warnings" != x""; then
   echo "Setting compiler warning flags = $build_warnings" 6>&1
 fi])dnl
 AC_ARG_ENABLE(sim-build-warnings,
-[  --enable-gdb-build-warnings Enable SIM specific build-time compiler warnings if gcc is used],
+AS_HELP_STRING([--enable-sim-build-warnings], [enable SIM specific build-time compiler warnings if gcc is used]),
 [case "${enableval}" in
   yes)	;;
   no)	build_warnings="-w";;
@@ -868,7 +881,6 @@ if test x"$silent" != x"yes" && test x"$build_warnings" != x""; then
   echo "Setting GDB specific compiler warning flags = $build_warnings" 6>&1
 fi])dnl
 WARN_CFLAGS=""
-WERROR_CFLAGS=""
 if test "x${build_warnings}" != x -a "x$GCC" = xyes
 then
     AC_MSG_CHECKING(compiler warning flags)
@@ -884,7 +896,7 @@ then
 	    CFLAGS="$saved_CFLAGS"
 	esac
     done
-    AC_MSG_RESULT(${WARN_CFLAGS}${WERROR_CFLAGS})
+    AC_MSG_RESULT(${WARN_CFLAGS} ${WERROR_CFLAGS})
 fi
 ])
 AC_SUBST(WARN_CFLAGS)