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libatomic: Fix up libat_{,un}lock_n for mingw [PR119796] 

Here is just a port of the previously posted patch to mingw which
clearly has the same problems.

2025-04-16  Jakub Jelinek  <jakub@redhat.com>

	PR libgcc/101075
	PR libgcc/119796
	* config/mingw/lock.c (libat_lock_n, libat_unlock_n): Start with
	computing how many locks will be needed and take into account
	((uintptr_t)ptr % WATCH_SIZE).  If some locks from the end of the
	locks array and others from the start of it will be needed, first
	lock the ones from the start followed by ones from the end.

(cherry picked from commit 34fe8e9000)
This commit is contained in:
Jakub Jelinek 2025-04-16 17:22:49 +02:00 committed by Jakub Jelinek
parent 50bd360f92
commit d490c5884b
1 changed files with 32 additions and 18 deletions
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50
libatomic/config/mingw/lock.c
View File

@ -87,21 +87,30 @@ libat_lock_n (void *ptr, size_t n)
{
uintptr_t h = addr_hash (ptr);
size_t i = 0;
size_t nlocks
= (n + ((uintptr_t)ptr % WATCH_SIZE) + WATCH_SIZE - 1) / WATCH_SIZE;
/* Don't lock more than all the locks we have. */
if (n > PAGE_SIZE)
n = PAGE_SIZE;
if (nlocks > NLOCKS)
nlocks = NLOCKS;
do
if (__builtin_expect (h + nlocks > NLOCKS, 0))
{
size_t j = h + nlocks - NLOCKS;
for (; i < j; ++i)
{
if (!locks[i].mutex)
locks[i].mutex = CreateMutex (NULL, FALSE, NULL);
WaitForSingleObject (locks[i].mutex, INFINITE);
}
}
for (; i < nlocks; ++i)
{
if (!locks[h].mutex)
locks[h].mutex = CreateMutex (NULL, FALSE, NULL);
WaitForSingleObject (locks[h].mutex, INFINITE);
if (++h == NLOCKS)
h = 0;
i += WATCH_SIZE;
locks[h].mutex = CreateMutex (NULL, FALSE, NULL);
WaitForSingleObject (locks[h++].mutex, INFINITE);
}
while (i < n);
}
void
@ -109,17 +118,22 @@ libat_unlock_n (void *ptr, size_t n)
{
uintptr_t h = addr_hash (ptr);
size_t i = 0;
size_t nlocks
= (n + ((uintptr_t)ptr % WATCH_SIZE) + WATCH_SIZE - 1) / WATCH_SIZE;
if (n > PAGE_SIZE)
n = PAGE_SIZE;
/* Don't lock more than all the locks we have. */
if (nlocks > NLOCKS)
nlocks = NLOCKS;
do
if (__builtin_expect (h + nlocks > NLOCKS, 0))
{
if (locks[h].mutex)
ReleaseMutex (locks[h].mutex);
if (++h == NLOCKS)
h = 0;
i += WATCH_SIZE;
size_t j = h + nlocks - NLOCKS;
for (; i < j; ++i)
if (locks[i].mutex)
ReleaseMutex (locks[i].mutex);
}
while (i < n);
for (; i < nlocks; ++i, ++h)
if (locks[h].mutex)
ReleaseMutex (locks[h].mutex);
}