Bug 28312

Summary:	maintenance_show_worker_threads lacks CXX_STD_THREAD guard
Product:	gdb	Reporter:	trass3r <trass3r>
Component:	build	Assignee:	Not yet assigned to anyone <unassigned>
Status:	RESOLVED FIXED
Severity:	normal	CC:	cbiesinger, vries
Priority:	P2
Version:	HEAD
Target Milestone:	12.1
Host:		Target:
Build:		Last reconfirmed:

Description trass3r 2021-09-07 09:20:37 UTC

https://github.com/bminor/binutils-gdb/blob/b4d9dd5c3576a8d6b1a59b11f8af1a3a2abd5fdc/gdb/maint.c#L850-L882

On MinGW this fails with:

gdb/maint.c:877:14: error: 'gdb::thread_pool' has not been declared
gdb::thread_pool::g_thread_pool->thread_count ());

Comment 1 Christian Biesinger 2021-09-07 16:02:21 UTC

does mingw not support std::thread?!

Comment 2 Tom de Vries 2021-09-08 07:04:10 UTC

https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=42f46152849a2d4bd06a87c2dc795de1f7fc1af7 :

[gdb/build] Fix build with undefined CXX_STD_THREAD

When building gdb on openSUSE Leap 42.3, we trigger the case that
CXX_STD_THREAD is undefined, and run into:
...
gdb/maint.c: In function 'void maintenance_show_worker_threads \
  (ui_file*, int, cmd_list_element*, const char*)':
gdb/maint.c:877:14: error: 'gdb::thread_pool' has not been declared
         gdb::thread_pool::g_thread_pool->thread_count ());
              ^
Makefile:1647: recipe for target 'maint.o' failed
make[1]: *** [maint.o] Error 1
...

Fix this by handling the undefined CXX_STD_THREAD case in
maintenance_show_worker_threads, such that we get:
...
$ gdb -q -batch -ex "maint show worker-thread"
The number of worker threads GDB can use is 0.
...

Tested on x86_64-linux.

Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28312

Comment 3 Tom de Vries 2021-09-08 07:08:31 UTC

(In reply to Christian Biesinger from comment #1)
> does mingw not support std::thread?!

gdbsupport/common.m4:
...
  # Check for std::thread.  This does not work on some platforms, like                             
  # mingw and DJGPP.                                                                               ...