[gdb] Initialize main_thread_id earlier
I wrote a patch using is_main_thread (), and found it returning false in the
main thread due to main_thread_id not being initialized yet.
Initialization currently takes place in _initialize_run_on_main_thread, but
that's too late for earlier uses.
Fix this by initializing, either:
- when entering main, or
- on an earlier first use.
Tested on x86_64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
diff --git a/gdb/gdb.c b/gdb/gdb.c
index 71a3fd1..6e3ff07 100644
--- a/gdb/gdb.c
+++ b/gdb/gdb.c
@@ -19,10 +19,17 @@
#include "defs.h"
#include "main.h"
#include "interps.h"
+#include "run-on-main-thread.h"
int
main (int argc, char **argv)
{
+ /* The first call to is_main_thread () should be from the main thread.
+ If this is the first call, then that requirement is fulfilled here.
+ If this is not the first call, then this verifies that the first call
+ fulfilled that requirement. */
+ gdb_assert (is_main_thread ());
+
struct captured_main_args args;
memset (&args, 0, sizeof args);
diff --git a/gdb/run-on-main-thread.c b/gdb/run-on-main-thread.c
index 91d25da..e5c9a77 100644
--- a/gdb/run-on-main-thread.c
+++ b/gdb/run-on-main-thread.c
@@ -94,12 +94,24 @@ run_on_main_thread (std::function<void ()> &&func)
serial_event_set (runnable_event);
}
+#if CXX_STD_THREAD
+static bool main_thread_id_initialized = false;
+#endif
+
/* See run-on-main-thread.h. */
bool
is_main_thread ()
{
#if CXX_STD_THREAD
+ /* Initialize main_thread_id on first use of is_main_thread. */
+ if (!main_thread_id_initialized)
+ {
+ main_thread_id_initialized = true;
+
+ main_thread_id = std::this_thread::get_id ();
+ }
+
return std::this_thread::get_id () == main_thread_id;
#else
return true;
@@ -111,7 +123,12 @@ void
_initialize_run_on_main_thread ()
{
#if CXX_STD_THREAD
- main_thread_id = std::this_thread::get_id ();
+ /* The variable main_thread_id should be initialized when entering main, or
+ at an earlier use, so it should already be initialized here. */
+ gdb_assert (main_thread_id_initialized);
+
+ /* Assume that we execute this in the main thread. */
+ gdb_assert (is_main_thread ());
#endif
runnable_event = make_serial_event ();
add_file_handler (serial_event_fd (runnable_event), run_events, nullptr,
