From 0c05bd3a9c165cf2f0b9d6fa23a1f96532ddcdb3 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Thu, 6 Sep 2012 23:34:10 -0400 Subject: [PATCH] further use of _Noreturn, for non-plain-C functions note that POSIX does not specify these functions as _Noreturn, because POSIX is aligned with C99, not the new C11 standard. when POSIX is eventually updated to C11, it will almost surely give these functions the _Noreturn attribute. for now, the actual _Noreturn keyword is not used anyway when compiling with a c99 compiler, which is what POSIX requires; the GCC __attribute__ is used instead if it's available, however. in a few places, I've added infinite for loops at the end of _Noreturn functions to silence compiler warnings. presumably __buildin_unreachable could achieve the same thing, but it would only work on newer GCCs and would not be portable. the loops should have near-zero code size cost anyway. like the previous _Noreturn commit, this one is based on patches contributed by philomath. --- include/assert.h | 9 ++++++++- include/err.h | 15 +++++++++++---- include/pthread.h | 9 ++++++++- include/setjmp.h | 4 ++-- include/unistd.h | 9 ++++++++- src/exit/_Exit.c | 2 +- src/exit/assert.c | 2 +- src/linux/err.c | 8 ++++---- src/signal/siglongjmp.c | 2 +- src/thread/pthread_create.c | 4 ++-- src/unistd/_exit.c | 2 +- 11 files changed, 47 insertions(+), 19 deletions(-) diff --git a/include/assert.h b/include/assert.h index bad2ccd0..30a43d68 100644 --- a/include/assert.h +++ b/include/assert.h @@ -1,5 +1,12 @@ #undef assert +#if __STDC_VERSION__ >= 201112L +#elif defined(__GNUC__) +#define _Noreturn __attribute__((__noreturn__)) +#else +#define _Noreturn +#endif + #ifdef NDEBUG #define assert(x) (void)0 #else @@ -10,7 +17,7 @@ extern "C" { #endif -void __assert_fail (const char *, const char *, int, const char *); +_Noreturn void __assert_fail (const char *, const char *, int, const char *); #ifdef __cplusplus } diff --git a/include/err.h b/include/err.h index 5e33f9e4..a6505c36 100644 --- a/include/err.h +++ b/include/err.h @@ -1,6 +1,13 @@ #ifndef _ERR_H #define _ERR_H +#if __STDC_VERSION__ >= 201112L +#elif defined(__GNUC__) +#define _Noreturn __attribute__((__noreturn__)) +#else +#define _Noreturn +#endif + #include #ifdef __cplusplus @@ -12,10 +19,10 @@ void vwarn(const char *, va_list); void warnx(const char *, ...); void vwarnx(const char *, va_list); -void err(int, const char *, ...); -void verr(int, const char *, va_list); -void errx(int, const char *, ...); -void verrx(int, const char *, va_list); +_Noreturn void err(int, const char *, ...); +_Noreturn void verr(int, const char *, va_list); +_Noreturn void errx(int, const char *, ...); +_Noreturn void verrx(int, const char *, va_list); #ifdef __cplusplus } diff --git a/include/pthread.h b/include/pthread.h index 417156c8..bc0d9f1c 100644 --- a/include/pthread.h +++ b/include/pthread.h @@ -10,6 +10,13 @@ extern "C" { #define __restrict #endif +#if __STDC_VERSION__ >= 201112L +#elif defined(__GNUC__) +#define _Noreturn __attribute__((__noreturn__)) +#else +#define _Noreturn +#endif + #define __NEED_time_t #define __NEED_clockid_t #define __NEED_struct_timespec @@ -79,7 +86,7 @@ extern "C" { int pthread_create(pthread_t *__restrict, const pthread_attr_t *__restrict, void *(*)(void *), void *__restrict); int pthread_detach(pthread_t); -void pthread_exit(void *); +_Noreturn void pthread_exit(void *); int pthread_join(pthread_t, void **); #ifdef __GNUC__ diff --git a/include/setjmp.h b/include/setjmp.h index 8ec5c6f1..e5877b44 100644 --- a/include/setjmp.h +++ b/include/setjmp.h @@ -24,14 +24,14 @@ typedef struct { unsigned long __ss[128/sizeof(long)]; } sigjmp_buf[1]; int sigsetjmp (sigjmp_buf, int); -void siglongjmp (sigjmp_buf, int); +_Noreturn void siglongjmp (sigjmp_buf, int); #endif #if defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \ || defined(_BSD_SOURCE) int _setjmp (jmp_buf); -void _longjmp (jmp_buf, int); +_Noreturn void _longjmp (jmp_buf, int); #endif diff --git a/include/unistd.h b/include/unistd.h index ecb23f81..20ba6ccb 100644 --- a/include/unistd.h +++ b/include/unistd.h @@ -11,6 +11,13 @@ extern "C" { #define __restrict #endif +#if __STDC_VERSION__ >= 201112L +#elif defined(__GNUC__) +#define _Noreturn __attribute__((__noreturn__)) +#else +#define _Noreturn +#endif + #define STDIN_FILENO 0 #define STDOUT_FILENO 1 #define STDERR_FILENO 2 @@ -90,7 +97,7 @@ int execl(const char *, const char *, ...); int execvp(const char *, char *const []); int execlp(const char *, const char *, ...); int fexecve(int, char *const [], char *const []); -void _exit(int); +_Noreturn void _exit(int); pid_t getpid(void); pid_t getppid(void); diff --git a/src/exit/_Exit.c b/src/exit/_Exit.c index c00a2ffb..7a6115c7 100644 --- a/src/exit/_Exit.c +++ b/src/exit/_Exit.c @@ -4,5 +4,5 @@ _Noreturn void _Exit(int ec) { __syscall(SYS_exit_group, ec); - __syscall(SYS_exit, ec); + for (;;) __syscall(SYS_exit, ec); } diff --git a/src/exit/assert.c b/src/exit/assert.c index e87442a7..49b0dc3e 100644 --- a/src/exit/assert.c +++ b/src/exit/assert.c @@ -1,7 +1,7 @@ #include #include -void __assert_fail(const char *expr, const char *file, int line, const char *func) +_Noreturn void __assert_fail(const char *expr, const char *file, int line, const char *func) { fprintf(stderr, "Assertion failed: %s (%s: %s: %d)\n", expr, file, func, line); fflush(NULL); diff --git a/src/linux/err.c b/src/linux/err.c index c291136d..0f748538 100644 --- a/src/linux/err.c +++ b/src/linux/err.c @@ -15,13 +15,13 @@ void vwarnx(const char *fmt, va_list ap) putc('\n', stderr); } -void verr(int status, const char *fmt, va_list ap) +_Noreturn void verr(int status, const char *fmt, va_list ap) { vwarn(fmt, ap); exit(status); } -void verrx(int status, const char *fmt, va_list ap) +_Noreturn void verrx(int status, const char *fmt, va_list ap) { vwarnx(fmt, ap); exit(status); @@ -43,7 +43,7 @@ void warnx(const char *fmt, ...) va_end(ap); } -void err(int status, const char *fmt, ...) +_Noreturn void err(int status, const char *fmt, ...) { va_list ap; va_start(ap, fmt); @@ -51,7 +51,7 @@ void err(int status, const char *fmt, ...) va_end(ap); } -void errx(int status, const char *fmt, ...) +_Noreturn void errx(int status, const char *fmt, ...) { va_list ap; va_start(ap, fmt); diff --git a/src/signal/siglongjmp.c b/src/signal/siglongjmp.c index e9a61314..d0e4f67d 100644 --- a/src/signal/siglongjmp.c +++ b/src/signal/siglongjmp.c @@ -3,7 +3,7 @@ #include #include "syscall.h" -void siglongjmp(sigjmp_buf buf, int ret) +_Noreturn void siglongjmp(sigjmp_buf buf, int ret) { if (buf->__fl) __syscall(SYS_rt_sigprocmask, SIG_SETMASK, buf->__ss, 0, __SYSCALL_SSLEN); diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c index 4567b41c..d8b8f0fc 100644 --- a/src/thread/pthread_create.c +++ b/src/thread/pthread_create.c @@ -8,7 +8,7 @@ weak_alias(dummy_0, __synccall_lock); weak_alias(dummy_0, __synccall_unlock); weak_alias(dummy_0, __pthread_tsd_run_dtors); -void pthread_exit(void *result) +_Noreturn void pthread_exit(void *result) { pthread_t self = pthread_self(); int n; @@ -43,7 +43,7 @@ void pthread_exit(void *result) __unmapself(self->map_base, self->map_size); } - __syscall(SYS_exit, 0); + for (;;) __syscall(SYS_exit, 0); } void __do_cleanup_push(struct __ptcb *cb) diff --git a/src/unistd/_exit.c b/src/unistd/_exit.c index d2e84c4c..76994823 100644 --- a/src/unistd/_exit.c +++ b/src/unistd/_exit.c @@ -1,7 +1,7 @@ #include #include -void _exit(int status) +_Noreturn void _exit(int status) { _Exit(status); } -- 2.25.1