On Fri, May 11, 2018 at 7:32 PM, James Byrne
<james.by...@origamienergy.com> wrote:
> Back in 2007, bb_simple_perror_msg() was introduced to allow for a lower
> overhead call to bb_perror_msg() when only a string was being printed
> with no parameters. This saves space 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 that time various 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_error_msg(),
> bb_error_msg_and_die(), bb_herror_msg() and bb_herror_msg_and_die(), and
> also overrides the standard versions with macros that use some
> preprocessor magic to automatically substitute any calls that only take
> a single parameter with the corresponding 'simple' version.
>
> All calls to the standard functions in the codebase that pass something
> like ("%s", arg) as the parameters have been replaced with 'simple'
> calls, as the macros can't fix these up.The patch is whitespace damaged, please send as attachment next time. > The space saving gained by this (using 'defconfig' on x86_64 with gcc > Ubuntu 6.4.0-17ubuntu1~16.04) was: > > ------------------------------------------------------------------------------ > (add/remove: 3/0 grow/shrink: 4/301 up/down: 73/-910) Total: -837 > bytes > text data bss dec hex filename > 936949 4263 1856 943068 e63dc busybox_old > 936098 4263 1856 942217 e6089 busybox_unstripped Can't reproduce: function old new delta bb_simple_herror_msg - 14 +14 bb_simple_error_msg - 14 +14 bb_simple_herror_msg_and_die - 11 +11 bb_simple_error_msg_and_die - 11 +11 sha1_process_block64 322 328 +6 expand_one_var 1599 1603 +4 fail_hunk 136 139 +3 mklocal 290 288 -2 xgethostbyname 27 23 -4 find_applet_by_name 128 124 -4 die 35 31 -4 chat_main 1379 1375 -4 arp_show 704 700 -4 arp_main 1455 1451 -4 add_interface 103 99 -4 acpid_main 1188 1184 -4 wget_main 2389 2384 -5 tftp_protocol 1839 1832 -7 getoptscmd 595 587 -8 builtin_read 210 202 -8 nfsmount 3556 3546 -10 ------------------------------------------------------------------------------ (add/remove: 4/0 grow/shrink: 3/14 up/down: 63/-72) Total: -9 bytes > +/* Override bb_error_msg() and related functions with macros that will > + * substitute them for the equivalent bb_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 _ARG16(_0, _1, _2, _3, _4, _5, _6, _7, _8, _9, _10, _11, _12, _13, > _14, _15, ...) _15 > +#define BB_MSG_KIND(...) _ARG16(__VA_ARGS__, , , , , , , , , , , , , , , > _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__) NAK this part. I prefer explicit use of _simple_ functions, not this magic conversion. _______________________________________________ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox
