From: Rusty Russell Date: Fri, 11 Jun 2010 03:36:40 +0000 (+0930) Subject: typesafe_cb: fix promotable types being incorrectly accepted by cast_if_type. X-Git-Url: https://git.ozlabs.org/?p=ccan;a=commitdiff_plain;h=894dd68a8c899ca7b5028334804fa1638b583908 typesafe_cb: fix promotable types being incorrectly accepted by cast_if_type. cast_if_type() should not try to degrade the expression using 1?(test):0, as that promotes bool to int, as well as degrading functions to function pointers: it should be done by the callers. In particular, this fixes sparse_bsearch. --- diff --git a/ccan/typesafe_cb/test/compile_fail-cast_if_type-promotable.c b/ccan/typesafe_cb/test/compile_fail-cast_if_type-promotable.c new file mode 100644 index 00000000..a0362485 --- /dev/null +++ b/ccan/typesafe_cb/test/compile_fail-cast_if_type-promotable.c @@ -0,0 +1,23 @@ +#include +#include + +static void _set_some_value(void *val) +{ +} + +#define set_some_value(expr) \ + _set_some_value(cast_if_type(void *, (expr), (expr), int)) + +int main(int argc, char *argv[]) +{ +#ifdef FAIL + bool x = 0; +#if !HAVE_TYPEOF||!HAVE_BUILTIN_CHOOSE_EXPR||!HAVE_BUILTIN_TYPES_COMPATIBLE_P +#error "Unfortunately we don't fail if cast_if_type is a noop." +#endif +#else + int x = 0; +#endif + set_some_value(x); + return 0; +} diff --git a/ccan/typesafe_cb/test/compile_ok-typesafe_cb-vars.c b/ccan/typesafe_cb/test/compile_ok-typesafe_cb-vars.c new file mode 100644 index 00000000..ce0700bc --- /dev/null +++ b/ccan/typesafe_cb/test/compile_ok-typesafe_cb-vars.c @@ -0,0 +1,52 @@ +#include +#include + +/* const args in callbacks should be OK. */ + +static void _register_callback(void (*cb)(void *arg), void *arg) +{ +} + +#define register_callback(cb, arg) \ + _register_callback(typesafe_cb(void, (cb), (arg)), (arg)) + +static void _register_callback_pre(void (*cb)(int x, void *arg), void *arg) +{ +} + +#define register_callback_pre(cb, arg) \ + _register_callback_pre(typesafe_cb_preargs(void, (cb), (arg), int), (arg)) + +static void _register_callback_post(void (*cb)(void *arg, int x), void *arg) +{ +} + +#define register_callback_post(cb, arg) \ + _register_callback_post(typesafe_cb_postargs(void, (cb), (arg), int), (arg)) + +struct undefined; + +static void my_callback(const struct undefined *undef) +{ +} + +static void my_callback_pre(int x, struct undefined *undef) +{ +} + +static void my_callback_post(struct undefined *undef, int x) +{ +} + +int main(int argc, char *argv[]) +{ + struct undefined *handle = NULL; + void (*cb)(const struct undefined *undef) = my_callback; + void (*pre)(int x, struct undefined *undef) = my_callback_pre; + void (*post)(struct undefined *undef, int x) = my_callback_post; + + register_callback(cb, handle); + register_callback_pre(pre, handle); + register_callback_post(post, handle); + return 0; +} diff --git a/ccan/typesafe_cb/typesafe_cb.h b/ccan/typesafe_cb/typesafe_cb.h index 4aabecf5..39b03124 100644 --- a/ccan/typesafe_cb/typesafe_cb.h +++ b/ccan/typesafe_cb/typesafe_cb.h @@ -12,9 +12,8 @@ * * This macro is used to create functions which allow multiple types. * The result of this macro is used somewhere that a @desttype type is - * expected: if @expr was of type @oktype, it will be cast to - * @desttype type. As a result, if @expr is any type other than - * @oktype or @desttype, a compiler warning will be issued. + * expected: if @test is exactly of type @oktype, then @expr will be + * cast to @desttype type, otherwise left alone. * * This macro can be used in static initializers. * @@ -31,7 +30,7 @@ * _set_some_value(cast_if_type(void *, (e), (e), unsigned long)) */ #define cast_if_type(desttype, expr, test, oktype) \ -__builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(test):0), oktype), \ + __builtin_choose_expr(__builtin_types_compatible_p(typeof(test), oktype), \ (desttype)(expr), (expr)) #else #define cast_if_type(desttype, expr, test, oktype) ((desttype)(expr)) @@ -105,10 +104,8 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(test):0), oktype), * #define register_callback(fn, arg) \ * _register_callback(typesafe_cb_const(void, (fn), (arg)), (arg)) */ -#define typesafe_cb_const(rtype, fn, arg) \ - sizeof((fn)((const void *)0)), \ - cast_if_type(rtype (*)(const void *), \ - (fn), (fn)(arg), rtype (*)(typeof(arg))) +#define typesafe_cb_const(rtype, fn, arg) \ + cast_if_type(rtype (*)(const void *), (fn), (fn)(arg), rtype) /** * typesafe_cb_preargs - cast a callback function if it matches the arg @@ -126,8 +123,9 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(test):0), oktype), * (arg)) */ #define typesafe_cb_preargs(rtype, fn, arg, ...) \ - cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), (fn), \ + cast_if_type(rtype (*)(__VA_ARGS__, void *), (fn), &*(fn), \ rtype (*)(__VA_ARGS__, typeof(arg))) + /** * typesafe_cb_postargs - cast a callback function if it matches the arg * @rtype: the return type of the callback function @@ -144,8 +142,9 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(test):0), oktype), * (arg)) */ #define typesafe_cb_postargs(rtype, fn, arg, ...) \ - cast_if_type(rtype (*)(void *, __VA_ARGS__), (fn), (fn), \ + cast_if_type(rtype (*)(void *, __VA_ARGS__), (fn), &*(fn), \ rtype (*)(typeof(arg), __VA_ARGS__)) + /** * typesafe_cb_cmp - cast a compare function if it matches the arg * @rtype: the return type of the callback function @@ -168,7 +167,7 @@ __builtin_choose_expr(__builtin_types_compatible_p(typeof(1?(test):0), oktype), * typesafe_cb_cmp(int, (cmpfn), (base)), (arg)) */ #define typesafe_cb_cmp(rtype, cmpfn, arg) \ - cast_if_type(rtype (*)(const void *, const void *), (cmpfn), \ + cast_if_type(rtype (*)(const void *, const void *), (cmpfn), &*(cmpfn), \ rtype (*)(const typeof(*arg)*, const typeof(*arg)*)) #endif /* CCAN_CAST_IF_TYPE_H */