From 6937487be73cd4563b876413277a295a5fe2f32c Mon Sep 17 00:00:00 2001 From: James Byrne Date: Tue, 2 Jul 2019 11:35:03 +0200 Subject: libbb: reduce the overhead of single parameter bb_error_msg() calls Back in 2007, commit 0c97c9d43707 ("'simple' error message functions by Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower overhead call to bb_perror_msg() when only a string was being printed with no parameters. This saves space for some CPU architectures because it avoids the overhead of a call to a variadic function. However there has never been a simple version of bb_error_msg(), and since 2007 many new calls to bb_perror_msg() have been added that only take a single parameter and so could have been using bb_simple_perror_message(). This changeset introduces 'simple' versions of bb_info_msg(), bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and replaces all calls that only take a single parameter, or use something like ("%s", arg), with calls to the corresponding 'simple' version. Since it is likely that single parameter calls to the variadic functions may be accidentally reintroduced in the future a new debugging config option WARN_SIMPLE_MSG has been introduced. This uses some macro magic which will cause any such calls to generate a warning, but this is turned off by default to avoid use of the unpleasant macros in normal circumstances. This is a large changeset due to the number of calls that have been replaced. The only files that contain changes other than simple substitution of function calls are libbb.h, libbb/herror_msg.c, libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c, networking/udhcp/common.h and util-linux/mdev.c additonal macros have been added for logging so that single parameter and multiple parameter logging variants exist. The amount of space saved varies considerably by architecture, and was found to be as follows (for 'defconfig' using GCC 7.4): Arm: -92 bytes MIPS: -52 bytes PPC: -1836 bytes x86_64: -938 bytes Note that for the MIPS architecture only an exception had to be made disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h) because it made these files larger on MIPS. Signed-off-by: James Byrne Signed-off-by: Denys Vlasenko --- include/libbb.h | 45 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 44 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/libbb.h b/include/libbb.h index 021100d..111d1b7 100644 --- a/include/libbb.h +++ b/include/libbb.h @@ -1137,7 +1137,7 @@ void exec_prog_or_SHELL(char **argv) NORETURN FAST_FUNC; ({ \ pid_t bb__xvfork_pid = vfork(); \ if (bb__xvfork_pid < 0) \ - bb_perror_msg_and_die("vfork"); \ + bb_simple_perror_msg_and_die("vfork"); \ bb__xvfork_pid; \ }) #if BB_MMU @@ -1324,13 +1324,17 @@ extern void (*die_func)(void); void xfunc_die(void) NORETURN FAST_FUNC; void bb_show_usage(void) NORETURN FAST_FUNC; void bb_error_msg(const char *s, ...) __attribute__ ((format (printf, 1, 2))) FAST_FUNC; +void bb_simple_error_msg(const char *s) FAST_FUNC; void bb_error_msg_and_die(const char *s, ...) __attribute__ ((noreturn, format (printf, 1, 2))) FAST_FUNC; +void bb_simple_error_msg_and_die(const char *s) NORETURN FAST_FUNC; void bb_perror_msg(const char *s, ...) __attribute__ ((format (printf, 1, 2))) FAST_FUNC; void bb_simple_perror_msg(const char *s) FAST_FUNC; void bb_perror_msg_and_die(const char *s, ...) __attribute__ ((noreturn, format (printf, 1, 2))) FAST_FUNC; void bb_simple_perror_msg_and_die(const char *s) NORETURN FAST_FUNC; void bb_herror_msg(const char *s, ...) __attribute__ ((format (printf, 1, 2))) FAST_FUNC; +void bb_simple_herror_msg(const char *s) FAST_FUNC; void bb_herror_msg_and_die(const char *s, ...) __attribute__ ((noreturn, format (printf, 1, 2))) FAST_FUNC; +void bb_simple_herror_msg_and_die(const char *s) NORETURN FAST_FUNC; void bb_perror_nomsg_and_die(void) NORETURN FAST_FUNC; void bb_perror_nomsg(void) FAST_FUNC; void bb_verror_msg(const char *s, va_list p, const char *strerr) FAST_FUNC; @@ -1339,12 +1343,51 @@ void bb_logenv_override(void) FAST_FUNC; #if ENABLE_FEATURE_SYSLOG_INFO void bb_info_msg(const char *s, ...) __attribute__ ((format (printf, 1, 2))) FAST_FUNC; +void bb_simple_info_msg(const char *s) FAST_FUNC; void bb_vinfo_msg(const char *s, va_list p) FAST_FUNC; #else #define bb_info_msg bb_error_msg +#define bb_simple_info_msg bb_simple_error_msg #define bb_vinfo_msg(s,p) bb_verror_msg(s,p,NULL) #endif +#if ENABLE_WARN_SIMPLE_MSG +/* If enabled, cause calls to bb_error_msg() et al that only take a single + * parameter to generate a warning. + */ +static inline void __attribute__ ((deprecated("use bb_simple_error_msg instead"))) + bb_not_simple_error_msg(const char *s) { bb_simple_error_msg(s); } +static inline void __attribute__ ((deprecated("use bb_simple_error_msg_and_die instead"))) NORETURN + bb_not_simple_error_msg_and_die(const char *s) { bb_simple_error_msg_and_die(s); } +static inline void __attribute__ ((deprecated("use bb_simple_perror_msg instead"))) + bb_not_simple_perror_msg(const char *s) { bb_simple_perror_msg(s); } +static inline void __attribute__ ((deprecated("use bb_simple_perror_msg_and_die instead"))) NORETURN + bb_not_simple_perror_msg_and_die(const char *s) { bb_simple_perror_msg_and_die(s); } +static inline void __attribute__ ((deprecated("use bb_simple_herror_msg instead"))) + bb_not_simple_herror_msg(const char *s) { bb_simple_herror_msg(s); } +static inline void __attribute__ ((deprecated("use bb_simple_herror_msg_and_die instead"))) NORETURN + bb_not_simple_herror_msg_and_die(const char *s) { bb_simple_herror_msg_and_die(s); } +static inline void __attribute__ ((deprecated("use bb_simple_info_msg instead"))) + bb_not_simple_info_msg(const char *s) { bb_simple_info_msg(s); } +/* Override bb_error_msg() and related functions with macros that will + * substitute them for the equivalent bb_not_simple_error_msg() function when + * they are used with only a single parameter. Macro approach inspired by + * https://gustedt.wordpress.com/2010/06/08/detect-empty-macro-arguments and + * https://gustedt.wordpress.com/2010/06/03/default-arguments-for-c99 + */ +#define _ARG18(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, _14, _15, _16, _17, ...) _17 +#define BB_MSG_KIND(...) _ARG18(__VA_ARGS__, , , , , , , , , , , , , , , , , _not_simple) +#define _BB_MSG(name, kind, ...) bb##kind##name(__VA_ARGS__) +#define BB_MSG(name, kind, ...) _BB_MSG(name, kind, __VA_ARGS__) +#define bb_error_msg(...) BB_MSG(_error_msg, BB_MSG_KIND(__VA_ARGS__), __VA_ARGS__) +#define bb_error_msg_and_die(...) BB_MSG(_error_msg_and_die, BB_MSG_KIND(__VA_ARGS__), __VA_ARGS__) +#define bb_perror_msg(...) BB_MSG(_perror_msg, BB_MSG_KIND(__VA_ARGS__), __VA_ARGS__) +#define bb_perror_msg_and_die(...) BB_MSG(_perror_msg_and_die, BB_MSG_KIND(__VA_ARGS__), __VA_ARGS__) +#define bb_herror_msg(...) BB_MSG(_herror_msg, BB_MSG_KIND(__VA_ARGS__), __VA_ARGS__) +#define bb_herror_msg_and_die(...) BB_MSG(_herror_msg_and_die, BB_MSG_KIND(__VA_ARGS__), __VA_ARGS__) +#define bb_info_msg(...) BB_MSG(_info_msg, BB_MSG_KIND(__VA_ARGS__), __VA_ARGS__) +#endif + /* We need to export XXX_main from libbusybox * only if we build "individual" binaries */ -- cgit v1.1