optimize out useless default-attribute object in pthread_create

diff --git a/src/thread/pthread_create.c b/src/thread/pthread_create.c
index 0609aab15ee89a31faef2f8ee38fe08c416eb527..a645f9fe3d3b1ab007210d971beb9cb487728e1c 100644 (file)
--- a/src/thread/pthread_create.c
+++ b/src/thread/pthread_create.c
@@ -61,10 +61,10 @@ weak_alias(dummy, __pthread_tsd_size);
 int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(void *), void *arg)
 {
        int ret;
-       size_t size, guard;
+       size_t size = DEFAULT_STACK_SIZE + DEFAULT_GUARD_SIZE;
+       size_t guard = DEFAULT_GUARD_SIZE;
        struct pthread *self = pthread_self(), *new;
        unsigned char *map, *stack, *tsd;
-       const pthread_attr_t default_attr = { 0 };
 
        if (!self) return ENOSYS;
        if (!libc.threaded) {
@@ -72,9 +72,10 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
                libc.threaded = 1;
        }
 
-       if (!attr) attr = &default_attr;
-       guard = ROUND(attr->_a_guardsize + DEFAULT_GUARD_SIZE);
-       size = guard + ROUND(attr->_a_stacksize + DEFAULT_STACK_SIZE);
+       if (attr) {
+               guard = ROUND(attr->_a_guardsize + DEFAULT_GUARD_SIZE);
+               size = guard + ROUND(attr->_a_stacksize + DEFAULT_STACK_SIZE);
+       }
        size += __pthread_tsd_size;
        map = mmap(0, size, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_ANON, -1, 0);
        if (!map) return EAGAIN;
@@ -90,8 +91,7 @@ int pthread_create(pthread_t *res, const pthread_attr_t *attr, void *(*entry)(vo
        new->start_arg = arg;
        new->self = new;
        new->tsd = (void *)tsd;
-       new->detached = attr->_a_detach;
-       new->attr = *attr;
+       if (attr) new->detached = attr->_a_detach;
        new->unblock_cancel = self->cancel;
        memcpy(new->tlsdesc, self->tlsdesc, sizeof new->tlsdesc);
        new->tlsdesc[1] = (uintptr_t)new;