elf: Use C11 atomics on _dl_mcount

All atomic operation are counters, so relaxed MO should be suffice.

Checked on x86_64-linux-gnu.
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
This commit is contained in:
Adhemerval Zanella 2022-09-20 16:04:13 -03:00
parent c0c9092f75
commit fd36873ff9

View File

@ -548,7 +548,7 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
size_t newfromidx; size_t newfromidx;
to_index = (data[narcs].self_pc to_index = (data[narcs].self_pc
/ (HASHFRACTION * sizeof (*tos))); / (HASHFRACTION * sizeof (*tos)));
newfromidx = catomic_exchange_and_add (&fromidx, 1) + 1; newfromidx = atomic_fetch_add_relaxed (&fromidx, 1) + 1;
froms[newfromidx].here = &data[narcs]; froms[newfromidx].here = &data[narcs];
froms[newfromidx].link = tos[to_index]; froms[newfromidx].link = tos[to_index];
tos[to_index] = newfromidx; tos[to_index] = newfromidx;
@ -558,14 +558,14 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
/* If we still have no entry stop searching and insert. */ /* If we still have no entry stop searching and insert. */
if (*topcindex == 0) if (*topcindex == 0)
{ {
unsigned int newarc = catomic_exchange_and_add (narcsp, 1); unsigned int newarc = atomic_fetch_add_relaxed (narcsp, 1);
/* In rare cases it could happen that all entries in FROMS are /* In rare cases it could happen that all entries in FROMS are
occupied. So we cannot count this anymore. */ occupied. So we cannot count this anymore. */
if (newarc >= fromlimit) if (newarc >= fromlimit)
goto done; goto done;
*topcindex = catomic_exchange_and_add (&fromidx, 1) + 1; *topcindex = atomic_fetch_add_relaxed (&fromidx, 1) + 1;
fromp = &froms[*topcindex]; fromp = &froms[*topcindex];
fromp->here = &data[newarc]; fromp->here = &data[newarc];
@ -573,7 +573,7 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
data[newarc].self_pc = selfpc; data[newarc].self_pc = selfpc;
data[newarc].count = 0; data[newarc].count = 0;
fromp->link = 0; fromp->link = 0;
catomic_increment (&narcs); atomic_fetch_add_relaxed (&narcs, 1);
break; break;
} }
@ -586,7 +586,7 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
} }
/* Increment the counter. */ /* Increment the counter. */
catomic_increment (&fromp->here->count); atomic_fetch_add_relaxed (&fromp->here->count, 1);
done: done:
; ;