libc: support 'thread_local' variable destructors

Fixes #4585

repos/libports/lib/symbols/libc

@@ -1294,6 +1294,7 @@ __cxa_guard_release T
 __cxa_init_primary_exception T
 __cxa_pure_virtual T
 __cxa_rethrow T
+__cxa_thread_atexit T
 __cxa_throw T
 __cxa_throw_bad_array_length T
 __cxa_throw_bad_array_new_length T

repos/libports/ports/libc.hash

@@ -1 +1 @@
-b856473bd43dea76e963f35bdbdd1d49d2d70e6b
+a4d148016cfbc4c494b277e164d67617cf540e31

repos/libports/src/lib/libc/patches/thread_local.patch

@@ -21,3 +21,23 @@
  #endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */
  
  /*
+--- src/lib/libc/lib/libc/stdlib/cxa_thread_atexit_impl.c.orig	2022-08-16 17:53:26.334343226 +0200
++++ src/lib/libc/lib/libc/stdlib/cxa_thread_atexit_impl.c	2022-08-17 13:37:34.445860493 +0200
+@@ -105,12 +105,17 @@
+ {
+ 	struct dl_phdr_info phdr_info;
+ 
++/* XXX this unload detection mechanism does not work on Genode */
++#if 0
+ 	if (_rtld_addr_phdr(dtor->dso, &phdr_info) &&
+ 	    __elf_phdr_match_addr(&phdr_info, dtor->func))
++#endif
+ 		dtor->func(dtor->obj);
++#if 0
+ 	else
+ 		fprintf(stderr, "__cxa_thread_call_dtors: dtr %p from "
+ 		    "unloaded dso, skipping\n", (void *)(dtor->func));
++#endif
+ }
+ 
+ static void

repos/libports/src/lib/libc/pthread.cc

@@ -685,8 +685,15 @@ extern "C" {
 	}
 
 
+	/* implemented in libc contrib sources */
+	void __cxa_thread_call_dtors();
+
 	void pthread_exit(void *value_ptr)
 	{
+		/* call 'thread_local' destructors */
+
+		__cxa_thread_call_dtors();
+
 		/* call TLS key destructors */
 
 		bool at_least_one_destructor_called;

repos/libports/src/test/pthread/main.cc

@@ -1153,6 +1153,46 @@ static void test_tls()
 }
 
 
+static bool thread_local_destructor_called = false;
+
+
+struct Thread_local
+{
+	int x = 0;
+
+	~Thread_local()
+	{
+		thread_local_destructor_called = true;
+	}
+};
+
+
+static thread_local Thread_local thread_local_var;
+
+
+static void *thread_local_test_func(void *)
+{
+	/* must access the variable to have the destructor called */
+	thread_local_var.x = 1;
+	return nullptr;
+}
+
+
+static void test_thread_local_destructor()
+{
+	pthread_t t;
+	void *retval;
+
+	pthread_create(&t, 0, thread_local_test_func, nullptr);
+	pthread_join(t, &retval);
+
+	if (!thread_local_destructor_called) {
+		Genode::error("thread_local destructor was not called");
+		exit(-1);
+	}
+}
+
+
 int main(int argc, char **argv)
 {
 	printf("--- pthread test ---\n");
@@ -1171,6 +1211,7 @@ int main(int argc, char **argv)
 	test_cond();
 	test_cleanup();
 	test_tls();
+	test_thread_local_destructor();
 
 	printf("--- returning from main ---\n");
 	return 0;