Add __libc_add_main_thread and mark it weak

This complements __libc_init_main_thread in setting up main thread
under native bridge.

Test: run_tests
Bug: 77877742
Change-Id: I53efab66f285a1b9f0ab36d44386fa1e2621e4ba

1 files changed, 9 insertions, 3 deletions

diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index c22f5718e..2396c3678 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -46,6 +46,7 @@
 #include "private/KernelArgumentBlock.h"
 #include "private/WriteProtected.h"
 #include "private/bionic_auxv.h"
+#include "private/bionic_defs.h"
 #include "private/bionic_globals.h"
 #include "private/bionic_tls.h"
 #include "private/thread_private.h"
@@ -107,6 +108,13 @@ static void arc4random_fork_handler() {
   _thread_arc4_lock();
 }
 
+__BIONIC_WEAK_FOR_NATIVE_BRIDGE
+void __libc_add_main_thread() {
+  // Get the main thread from TLS and add it to the thread list.
+  pthread_internal_t* main_thread = __get_thread();
+  __pthread_internal_add(main_thread);
+}
+
 void __libc_init_common(KernelArgumentBlock& args) {
   // Initialize various globals.
   environ = args.envp;
@@ -118,9 +126,7 @@ void __libc_init_common(KernelArgumentBlock& args) {
   __check_max_thread_id();
 #endif
 
-  // Get the main thread from TLS and add it to the thread list.
-  pthread_internal_t* main_thread = __get_thread();
-  __pthread_internal_add(main_thread);
+  __libc_add_main_thread();
 
   // Register atfork handlers to take and release the arc4random lock.
   pthread_atfork(arc4random_fork_handler, _thread_arc4_unlock, _thread_arc4_unlock);