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--- /exception.cc (index)
+++ /exception.cc (working tree)
@@ -331,6 +373,44 @@ static void free_exception_list(__cxa_exception *ex)
__cxa_free_exception(ex+1);
}
+#define fast_ti_size 100
+
+static long fast_ti_index;
+static __cxa_thread_info fast_ti[fast_ti_size];
+
+static inline __cxa_thread_info* alloc_thread_info() {
+ {
+ long cur_index;
+
+ __atomic_load(&fast_ti_index, &cur_index, __ATOMIC_SEQ_CST);
+
+ // exausted long time ago
+ if (cur_index >= fast_ti_size) {
+ return static_cast<__cxa_thread_info*>(calloc(1, sizeof(__cxa_thread_info)));
+ }
+ }
+
+ auto my_index = __sync_fetch_and_add(&fast_ti_index, 1);
+
+ // exausted
+ if (my_index >= fast_ti_size) {
+ return static_cast<__cxa_thread_info*>(calloc(1, sizeof(__cxa_thread_info)));
+ }
+
+ // fast path
+ auto& ret = fast_ti[my_index];
+
+ memset(&ret, 0, sizeof(ret));
+
+ return &ret;
+}
+
+static inline void free_thread_info(__cxa_thread_info* ti) {
+ if ((ti < fast_ti) || (ti >= (fast_ti + fast_ti_size))) {
+ free(ti);
+ }
+}
+
/**
* Cleanup function called when a thread exists to make certain that all of the
* per-thread data is deleted.
@@ -352,10 +352,9 @@ static void thread_cleanup(void* thread_info)
free_exception_list(info->globals.caughtExceptions);
}
}
- free(thread_info);
+ free_thread_info(info);
}
-
/**
* Once control used to protect the key creation.
*/
@@ -389,11 +388,16 @@ static void init_key(void)
pthread_setspecific(eh_key, 0);
}
+static __thread __cxa_thread_info* THR_INFO = nullptr;
+
/**
* Returns the thread info structure, creating it if it is not already created.
*/
static __cxa_thread_info *thread_info()
{
+ if (THR_INFO) {
+ return THR_INFO;
+ }
if ((0 == pthread_once) || pthread_once(&once_control, init_key))
{
fakeTLS = true;
@@ -402,17 +406,29 @@ static __cxa_thread_info *thread_info()
__cxa_thread_info *info = static_cast<__cxa_thread_info*>(pthread_getspecific(eh_key));
if (0 == info)
{
- info = static_cast<__cxa_thread_info*>(calloc(1, sizeof(__cxa_thread_info)));
+ info = alloc_thread_info();
pthread_setspecific(eh_key, info);
}
+ THR_INFO = info;
return info;
}
+
+// ensure main thread will allocate preallocated tls
+static struct InitMainTls {
+ inline InitMainTls() {
+ thread_info();
+ }
+} init_main_tls;
+
/**
* Fast version of thread_info(). May fail if thread_info() is not called on
* this thread at least once already.
*/
static __cxa_thread_info *thread_info_fast()
{
+ if (THR_INFO) {
+ return THR_INFO;
+ }
if (fakeTLS) { return &singleThreadInfo; }
return static_cast<__cxa_thread_info*>(pthread_getspecific(eh_key));
}
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