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-rw-r--r--gphoto-m4/gp-pedantic-compiler-flags.m4108
1 files changed, 97 insertions, 11 deletions
diff --git a/gphoto-m4/gp-pedantic-compiler-flags.m4 b/gphoto-m4/gp-pedantic-compiler-flags.m4
index b84aa0b51..1b690428c 100644
--- a/gphoto-m4/gp-pedantic-compiler-flags.m4
+++ b/gphoto-m4/gp-pedantic-compiler-flags.m4
@@ -7,14 +7,30 @@ dnl ####################################################################
dnl GP_CONDITIONAL_COMPILE_FLAGS(FLAG_VAR, FLAGS)
dnl ####################################################################
AC_DEFUN([GP_CONDITIONAL_COMPILE_FLAGS], [dnl
+dnl
# BEGIN $0($@)
-AS_VAR_IF([$1], [], [dnl
- $1="$2"
-], [dnl
- $1="[$]{$1} $2"
-])
-AC_MSG_CHECKING([whether $1="[$]$1" compiles])
-AC_COMPILE_IFELSE([m4_case([$1], [CFLAGS], [dnl
+dnl
+m4_pushdef([the_lang],
+ [m4_case([$1],
+ [CFLAGS], [C],
+ [CXXFLAGS], [C++],
+ [m4_fatal([unhandled compiler flags variable: ][$1])])])dnl
+dnl
+AC_LANG_PUSH(the_lang)dnl
+dnl
+dnl If $2 is a warning option, normalize it, as -Wno-foo will compile
+dnl successfully, regardless of whether the compiler even knows the
+dnl -Wfoo warning. FIXME: Split $2 and operate on each part?
+m4_pushdef([normalized_option],
+ [m4_bpatsubst([$2],
+ [^-W\(no-\)?\(error=\)?\([-_0-9a-zA-Z=]+\)$],
+ [-W\3])])dnl
+dnl
+saved_$1="${$1}"
+$1="${saved_$1} normalized_option -Werror"
+AC_MSG_CHECKING([whether $1 can append $2])
+AC_COMPILE_IFELSE([dnl
+m4_case(the_lang, [C], [dnl
AC_LANG_SOURCE([[
#include <stdio.h>
int main(int argc, char *argv[])
@@ -27,7 +43,7 @@ int main(int argc, char *argv[])
return 0;
}
]])dnl
-], [CXXFLAGS], [dnl
+], [C++], [dnl
AC_LANG_SOURCE([[
#include <iostream>
int main(int argc, char *argv[])
@@ -40,14 +56,18 @@ int main(int argc, char *argv[])
return 0;
}
]])dnl
-], [m4_fatal([wrong compiler flag])])], [dnl
- : "Added flag $2 to $1 and it works"
+], [m4_fatal([unhandled language ]the_lang)])dnl
+], [dnl
AC_MSG_RESULT([yes])
+ $1="${saved_$1} $2"
], [dnl
- : "Added flag $2 to $1 and it does not work"
AC_MSG_RESULT([no])
gp_have_pedantic_compiler=no
+ $1="$saved_$1"
])
+m4_popdef([normalized_option])dnl
+AC_LANG_POP(the_lang)dnl
+m4_popdef([the_lang])dnl
# END $0($@)
])dnl
dnl
@@ -117,6 +137,72 @@ dnl
dnl
dnl ####################################################################
dnl
+dnl GP_WITH_EMPTY_CONFDEFS_H
+dnl
+dnl Usage:
+dnl GP_WITH_EMPTY_CONFDEFS_H([
+dnl GP_CONDITIONAL_COMPILE_FLAGS([CFLAGS], [-Wno-foo])
+dnl GP_CONDITIONAL_COMPILE_FLAGS([CFLAGS], [-Wno-bar])
+dnl ])dnl
+dnl
+dnl Since autoconf 2.63b, the macros defined by AC_DEFINE so far
+dnl (mostly PACKAGE, VERSION, etc.) are in confdefs.h by now and are
+dnl included using AC_LANG_SOURCE or AC_LANG_PROGRAM.
+dnl
+dnl We cannot use a confdefs.h with macro definitions for the pedantic
+dnl compilation tests as that pedantic compilation might complain
+dnl about macros being defined but not used.
+dnl
+dnl We also cannot just put AC_LANG_DEFINES_PROVIDED inside the
+dnl program, as that will make sure the program starts with the
+dnl current content of confdefs.h.
+dnl
+dnl In order to be able to test compile programs without any macro
+dnl definitions from confdefs.ht, we save the original confdefs.h file
+dnl and use an empty confdefs.h for our checks, then restore the
+dnl original confdefs.h after our checks are done.
+dnl
+dnl Of course, we must not append to confdefs.h by e.g. calling
+dnl AC_DEFINE or AC_DEFINE_UNQUOTED until the original confdefs.h has
+dnl been restored, as those definitions would then be lost.
+dnl
+dnl ####################################################################
+AC_DEFUN([GP_WITH_EMPTY_CONFDEFS_H], [dnl
+m4_pushdef([AC_DEFINE],
+ [m4_fatal([Must not use AC_DEFINE inside $0])])dnl
+m4_pushdef([AC_DEFINE_UNQUOTED],
+ [m4_fatal([Must not use AC_DEFINE_UNQUOTED inside $0])])dnl
+cat confdefs.h
+AC_MSG_NOTICE([saving original confdefs.h and creating empty confdefs.h])
+rm -f confdefs.h.saved
+mv confdefs.h confdefs.h.saved
+cat <<EOF >confdefs.h
+/* confdefs.h forced empty for the pedantic compile tests */
+EOF
+dnl
+AC_MSG_CHECKING([CFLAGS value before])
+AC_MSG_RESULT([$CFLAGS])
+AC_MSG_CHECKING([CXXFLAGS value before])
+AC_MSG_RESULT([$CXXFLAGS])
+dnl
+$1
+dnl
+AC_MSG_CHECKING([CFLAGS value after])
+AC_MSG_RESULT([$CFLAGS])
+AC_MSG_CHECKING([CXXFLAGS value after])
+AC_MSG_RESULT([$CXXFLAGS])
+dnl
+AC_MSG_NOTICE([restoring original confdefs.h])
+rm -f confdefs.h
+mv confdefs.h.saved confdefs.h
+cat confdefs.h
+m4_popdef([AC_DEFINE_UNQUOTED])dnl
+m4_popdef([AC_DEFINE])dnl
+])dnl
+dnl
+dnl
+dnl ####################################################################
+dnl
dnl Local Variables:
dnl mode: autoconf
dnl End: