On Sat, Jul 10, 2010 at 10:39:22AM +0200, Jiri Slaby wrote:
> Gcc 4.5 defines
> extern void __builtin_unreachable(void);
> so, add it also to sparse.
>
> Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
> ---
> lib.c | 1 +
> 1 files changed, 1 insertions(+), 0 deletions(-)
>
> diff --git a/lib.c b/lib.c
> index a218bfc..ae6a20c 100644
> --- a/lib.c
> +++ b/lib.c
> @@ -740,6 +740,7 @@ void declare_builtin_functions(void)
> add_pre_buffer ("extern char * __builtin___strncpy_chk(char *, const char *, __SIZE_TYPE__, __SIZE_TYPE__);\n");
> add_pre_buffer ("extern int __builtin___vsprintf_chk(char *, int, __SIZE_TYPE__, const char *, __builtin_va_list);\n");
> add_pre_buffer ("extern int __builtin___vsnprintf_chk(char *, __SIZE_TYPE__, int, __SIZE_TYPE__, const char *, __builtin_va_list ap);\n");
> + add_pre_buffer ("extern void __builtin_unreachable(void);\n");
__builtin_unreachable has special semantics beyond just a function.
This definition will suffice to allow compilation, but
__builtin_unreachable should have the same effect in sparse that it does
in GCC: mark the point (and the remainder of the basic block) as
unreachable. Something like the mechanism used for handling noreturn
would work here as well; declaring the function to have attribute
noreturn would probably have almost the right semantics.
- Josh Triplett
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