Add a makefile check for misbehaving -Wcomment

[filcab]

Summary

gcc's (4.7 at least) -Wcomment warns on line-comment -> backslash ->
newline -> line-comment, while clang doesn't.
If gcc behaves that way, silence -Wcomment.
cmake already has this.

[filcab]

Eric, is that huge added block a problem? I'm not sure why autoconf changed what it had.

My env is:

$ ./autoconf/AutoRegen.sh

### NOTE: ############################################################
### If you get *any* warnings from autoconf below you MUST fix the
### scripts in the m4 directory because there are future forward
### compatibility or platform support issues at risk. Please do NOT
### commit any configure script that was generated with warnings
### present. You should get just three 'Regenerating..' lines.
######################################################################

Regenerating aclocal.m4 with aclocal 1.9.6
Regenerating configure with autoconf 2.60
Regenerating config.h.in with autoheader 2.60

configure

19786

I'm not sure why this changed to the huge block @ line 19892

[echristo]

I'm not seeing the changes you're seeing when I regenerate. I'm seeing a couple of random line changes later, but not that part.

The patch itself looks fine so I'm going to go ahead and commit it on your behalf with a regenerated configure.

Makefile.config.in

 # -Wno-variadic-macros
 NO_VARIADIC_MACROS = @NO_VARIADIC_MACROS@
 # -Wcovered-switch-default
 COVERED_SWITCH_DEFAULT = @COVERED_SWITCH_DEFAULT@
 # -Wno-uninitialized
 NO_UNINITIALIZED = @NO_UNINITIALIZED@
 # -Wno-maybe-uninitialized
 NO_MAYBE_UNINITIALIZED = @NO_MAYBE_UNINITIALIZED@
+# -Wno-comment
+NO_COMMENT = @NO_COMMENT@
 
 # Was polly found in tools/polly?
 LLVM_HAS_POLLY = @LLVM_HAS_POLLY@
 # Flags supported by the linker.
 # bfd ld / gold --version-script=file
 HAVE_LINK_VERSION_SCRIPT = @HAVE_LINK_VERSION_SCRIPT@
 
 # Flags to control using libxml2

Makefile.rules

 endif
 
 ifndef NO_PEDANTIC
 CompileCommonOpts += -pedantic -Wno-long-long
 endif
 CompileCommonOpts += -Wall -W -Wno-unused-parameter -Wwrite-strings \
                      $(EXTRA_OPTIONS) $(COVERED_SWITCH_DEFAULT) \
                      $(NO_UNINITIALIZED) $(NO_MAYBE_UNINITIALIZED) \
-                     $(NO_MISSING_FIELD_INITIALIZERS)
+                     $(NO_MISSING_FIELD_INITIALIZERS) $(NO_COMMENT)
 # Enable cast-qual for C++; the workaround is to use const_cast.
 CXX.Flags += -Wcast-qual
 
 ifeq ($(HOST_OS),HP-UX)
   CompileCommonOpts := -D_REENTRANT -D_HPUX_SOURCE
 endif
 
 # If we are building a universal binary on Mac OS X, pass extra options.  This

autoconf/configure.ac

then
   dnl gcc 4.7 introduced -Wmaybe-uninitialized to distinguish cases which are
   dnl known to be uninitialized from cases which might be uninitialized.  We
   dnl still want to catch the first kind of errors.
   if test -z "$NO_MAYBE_UNINITIALIZED"
   then
     CXX_FLAG_CHECK(NO_UNINITIALIZED, [-Wno-uninitialized])
   fi
 fi
-AC_MSG_RESULT([$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED])
+
+dnl Check for misbehaving -Wcomment (gcc-4.7 has this) and maybe add
+dnl -Wno-comment to the flags.
+no_comment=
+llvm_cv_old_cxxflags="$CXXFLAGS"
+CXXFLAGS="$CXXFLAGS -Wcomment -Werror"
+AC_COMPILE_IFELSE(
+[
+  AC_LANG_SOURCE([[// Comment \o\
+// Another comment
+int main() { return 0; }
+  ]])
+],
+[
+  no_comment=-Wno-comment
+],
+[])
+AC_SUBST(NO_COMMENT, [$no_comment])
+CXXFLAGS="$llvm_cv_old_cxxflags"
+
+AC_MSG_RESULT([$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED $NO_COMMENT])
 
 AC_ARG_WITH([python],
             [AS_HELP_STRING([--with-python], [path to python])],
             [PYTHON="$withval"])
 
 if test -n "$PYTHON" && test -x "$PYTHON" ; then
   AC_MSG_CHECKING([for python])
   AC_MSG_RESULT([user defined: $with_python])

configure

 GAS
 HAVE_LINK_VERSION_SCRIPT
 EGREP
 NO_VARIADIC_MACROS
 NO_MISSING_FIELD_INITIALIZERS
 COVERED_SWITCH_DEFAULT
 NO_MAYBE_UNINITIALIZED
 NO_UNINITIALIZED
+NO_COMMENT
 PYTHON
 HAVE_DLOPEN
 HAVE_TERMINFO
 USE_OPROFILE
 USE_INTEL_JITEVENTS
 XML2CONFIG
 LIBXML2_LIBS
 LIBXML2_INC
then
   NO_MAYBE_UNINITIALIZED=`$CXX -Werror -Wmaybe-uninitialized -fsyntax-only -xc /dev/null 2>/dev/null && echo -Wno-maybe-uninitialized`
 
         if test -z "$NO_MAYBE_UNINITIALIZED"
   then
     NO_UNINITIALIZED=`$CXX -Werror -Wuninitialized -fsyntax-only -xc /dev/null 2>/dev/null && echo -Wno-uninitialized`
 
   fi
 fi
-{ echo "$as_me:$LINENO: result: $NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED" >&5
-echo "${ECHO_T}$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED" >&6; }
+
+no_comment=
+llvm_cv_old_cxxflags="$CXXFLAGS"
+CXXFLAGS="$CXXFLAGS -Wcomment -Werror"
+cat >conftest.$ac_ext <<_ACEOF
+
+  /* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+// Comment \o\
+// Another comment
+int main() { return 0; }
+
+
+_ACEOF
+rm -f conftest.$ac_objext
+if { (ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_compile") 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+   { ac_try='test -z "$ac_c_werror_flag" || test ! -s conftest.err'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+   { ac_try='test -s conftest.$ac_objext'
+  { (case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+
+  no_comment=-Wno-comment
+
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+
+fi
+
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+NO_COMMENT=$no_comment
+
+CXXFLAGS="$llvm_cv_old_cxxflags"
+
+{ echo "$as_me:$LINENO: result: $NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED $NO_COMMENT" >&5
+echo "${ECHO_T}$NO_VARIADIC_MACROS $NO_MISSING_FIELD_INITIALIZERS $COVERED_SWITCH_DEFAULT $NO_UNINITIALIZED $NO_MAYBE_UNINITIALIZED $NO_COMMENT" >&6; }
 
 
 # Check whether --with-python was given.
 if test "${with_python+set}" = set; then
   withval=$with_python; PYTHON="$withval"
 fi
 
 

 GAS!$GAS$ac_delim
 HAVE_LINK_VERSION_SCRIPT!$HAVE_LINK_VERSION_SCRIPT$ac_delim
 EGREP!$EGREP$ac_delim
 NO_VARIADIC_MACROS!$NO_VARIADIC_MACROS$ac_delim
 NO_MISSING_FIELD_INITIALIZERS!$NO_MISSING_FIELD_INITIALIZERS$ac_delim
 COVERED_SWITCH_DEFAULT!$COVERED_SWITCH_DEFAULT$ac_delim
 NO_MAYBE_UNINITIALIZED!$NO_MAYBE_UNINITIALIZED$ac_delim
 NO_UNINITIALIZED!$NO_UNINITIALIZED$ac_delim
+NO_COMMENT!$NO_COMMENT$ac_delim
 PYTHON!$PYTHON$ac_delim
 HAVE_DLOPEN!$HAVE_DLOPEN$ac_delim
 HAVE_TERMINFO!$HAVE_TERMINFO$ac_delim
 USE_OPROFILE!$USE_OPROFILE$ac_delim
 USE_INTEL_JITEVENTS!$USE_INTEL_JITEVENTS$ac_delim
 XML2CONFIG!$XML2CONFIG$ac_delim
 LIBXML2_LIBS!$LIBXML2_LIBS$ac_delim
 LIBXML2_INC!$LIBXML2_INC$ac_delim

 LLVM_CONFIGTIME!$LLVM_CONFIGTIME$ac_delim
 BINDINGS_TO_BUILD!$BINDINGS_TO_BUILD$ac_delim
 OCAML_LIBDIR!$OCAML_LIBDIR$ac_delim
 ENABLE_VISIBILITY_INLINES_HIDDEN!$ENABLE_VISIBILITY_INLINES_HIDDEN$ac_delim
 RPATH!$RPATH$ac_delim
 RDYNAMIC!$RDYNAMIC$ac_delim
 program_prefix!$program_prefix$ac_delim
 LIBOBJS!$LIBOBJS$ac_delim
-LTLIBOBJS!$LTLIBOBJS$ac_delim
 _ACEOF
 
   if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 97; then
     break
   elif $ac_last_try; then
     { { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5
 echo "$as_me: error: could not make $CONFIG_STATUS" >&2;}
    { (exit 1); exit 1; }; }

 N; s/^.*\n//; s/[,\\&]/\\&/g; s/@/@|#_!!_#|/g; b n
 ' >>$CONFIG_STATUS <conf$$subs.sed
 rm -f conf$$subs.sed
 cat >>$CONFIG_STATUS <<_ACEOF
 CEOF$ac_eof
 _ACEOF
 
 
+ac_delim='%!_!# '
+for ac_last_try in false false false false false :; do
+  cat >conf$$subs.sed <<_ACEOF
+LTLIBOBJS!$LTLIBOBJS$ac_delim
+_ACEOF
+
+  if test `sed -n "s/.*$ac_delim\$/X/p" conf$$subs.sed | grep -c X` = 1; then
+    break
+  elif $ac_last_try; then
+    { { echo "$as_me:$LINENO: error: could not make $CONFIG_STATUS" >&5
+echo "$as_me: error: could not make $CONFIG_STATUS" >&2;}
+   { (exit 1); exit 1; }; }
+  else
+    ac_delim="$ac_delim!$ac_delim _$ac_delim!! "
+  fi
+done
+
+ac_eof=`sed -n '/^CEOF[0-9]*$/s/CEOF/0/p' conf$$subs.sed`
+if test -n "$ac_eof"; then
+  ac_eof=`echo "$ac_eof" | sort -nru | sed 1q`
+  ac_eof=`expr $ac_eof + 1`
+fi
+
+cat >>$CONFIG_STATUS <<_ACEOF
+cat >"\$tmp/subs-3.sed" <<\CEOF$ac_eof
+/@[a-zA-Z_][a-zA-Z_0-9]*@/!b end
+_ACEOF
+sed '
+s/[,\\&]/\\&/g; s/@/@|#_!!_#|/g
+s/^/s,@/; s/!/@,|#_!!_#|/
+:n
+t n
+s/'"$ac_delim"'$/,g/; t
+s/$/\\/; p
+N; s/^.*\n//; s/[,\\&]/\\&/g; s/@/@|#_!!_#|/g; b n
+' >>$CONFIG_STATUS <conf$$subs.sed
+rm -f conf$$subs.sed
+cat >>$CONFIG_STATUS <<_ACEOF
+:end
+s/|#_!!_#|//g
+CEOF$ac_eof
+_ACEOF
+
+
 # VPATH may cause trouble with some makes, so we remove $(srcdir),
 # ${srcdir} and @srcdir@ from VPATH if srcdir is ".", strip leading and
 # trailing colons and then remove the whole line if VPATH becomes empty
 # (actually we leave an empty line to preserve line numbers).
 if test "x$srcdir" = x.; then
   ac_vpsub='/^[   ]*VPATH[  ]*=/{
 s/:*\$(srcdir):*/:/
 s/:*\${srcdir}:*/:/

 s&@abs_srcdir@&$ac_abs_srcdir&;t t
 s&@top_srcdir@&$ac_top_srcdir&;t t
 s&@abs_top_srcdir@&$ac_abs_top_srcdir&;t t
 s&@builddir@&$ac_builddir&;t t
 s&@abs_builddir@&$ac_abs_builddir&;t t
 s&@abs_top_builddir@&$ac_abs_top_builddir&;t t
 s&@INSTALL@&$ac_INSTALL&;t t
 $ac_datarootdir_hack
-" $ac_file_inputs | sed -f "$tmp/subs-1.sed" | sed -f "$tmp/subs-2.sed" | sed 's/|#_!!_#|//g' >$tmp/out
+" $ac_file_inputs | sed -f "$tmp/subs-1.sed" | sed -f "$tmp/subs-2.sed" | sed -f "$tmp/subs-3.sed" >$tmp/out
 
 test -z "$ac_datarootdir_hack$ac_datarootdir_seen" &&
   { ac_out=`sed -n '/\${datarootdir}/p' "$tmp/out"`; test -n "$ac_out"; } &&
   { ac_out=`sed -n '/^[   ]*datarootdir[  ]*:*=/p' "$tmp/out"`; test -z "$ac_out"; } &&
   { echo "$as_me:$LINENO: WARNING: $ac_file contains a reference to the variable \`datarootdir'
 which seems to be undefined.  Please make sure it is defined." >&5
 echo "$as_me: WARNING: $ac_file contains a reference to the variable \`datarootdir'
 which seems to be undefined.  Please make sure it is defined." >&2;}