From 619d9b5e6848a72350126ea9c1e413fd133181e3 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 28 Jul 2017 15:28:33 +0200 Subject: ash: less hackish implementation of evaltreenr() Defining a function alias with __attribute__ ((alias("evaltree"),__noreturn__)) is not that usual, and clang had a bug which made it misunderstand this construct. Switch to: ALWAYS_INLINE NORETURN evaltreenr() { evaltree(); unreachable(); } Older gcc's do not know unreachable(), on them we pay the price of having a few extra calls to abort(): function old new delta evalsubshell 151 156 +5 evalpipe 357 362 +5 argstr 1141 1144 +3 On newer gcc, code size does not change. Signed-off-by: Denys Vlasenko --- shell/ash.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) (limited to 'shell') diff --git a/shell/ash.c b/shell/ash.c index f74fbd7..1f5a8da 100644 --- a/shell/ash.c +++ b/shell/ash.c @@ -6137,6 +6137,19 @@ struct backcmd { /* result of evalbackcmd */ #define EV_TESTED 02 /* exit status is checked; ignore -e flag */ static int evaltree(union node *, int); +/* An evaltree() which is known to never return. + * Used to use an alias: + * static int evaltreenr(union node *, int) __attribute__((alias("evaltree"),__noreturn__)); + * but clang was reported to "transfer" noreturn-ness to evaltree() as well. + */ +static ALWAYS_INLINE NORETURN void +evaltreenr(union node *n, int flags) +{ + evaltree(n, flags); + bb_unreachable(abort()); + /* NOTREACHED */ +} + static void FAST_FUNC evalbackcmd(union node *n, struct backcmd *result) { @@ -6173,7 +6186,7 @@ evalbackcmd(union node *n, struct backcmd *result) */ eflag = 0; ifsfree(); - evaltree(n, EV_EXIT); /* actually evaltreenr... */ + evaltreenr(n, EV_EXIT); /* NOTREACHED */ } /* parent */ @@ -8796,11 +8809,6 @@ evaltree(union node *n, int flags) return exitstatus; } -#if !defined(__alpha__) || (defined(__GNUC__) && __GNUC__ >= 3) -static -#endif -int evaltreenr(union node *, int) __attribute__ ((alias("evaltree"),__noreturn__)); - static int skiploop(void) { -- cgit v1.1