* src/thread.h (m_getcjmp): New member of 'struct thread_state'.
(getcjmp): Define to current thread's 'm_getcjmp'.
* src/thread.c (maybe_reacquire_global_lock): Switch to main
thread, since this is called from a SIGINT handler, which always
runs in the context of the main thread.
* src/lisp.h (sys_jmp_buf, sys_setjmp, sys_longjmp): Move the
definitions before thread.h is included, as thread.h now uses
sys_jmp_buf.
* src/keyboard.c (getcjmp): Remove declaration.
(read_char): Don't call maybe_reacquire_global_lock here.
(handle_interrupt): Call maybe_reacquire_global_lock here, if
invoked from the SIGINT handler, to make sure
quit_throw_to_read_char runs with main thread's Lisp bindings and
uses the main thread's jmp_buf buffer. (Bug#28630)
Most of this change is to boilerplate commentary such as license URLs.
This change was prompted by ftp://ftp.gnu.org's going-away party,
planned for November. Change these FTP URLs to https://ftp.gnu.org
instead. Make similar changes for URLs to other organizations moving
away from FTP. Also, change HTTP to HTTPS for URLs to gnu.org and
fsf.org when this works, as this will further help defend against
man-in-the-middle attacks (for this part I omitted the MS-DOS and
MS-Windows sources and the test tarballs to keep the workload down).
HTTPS is not fully working to lists.gnu.org so I left those URLs alone
for now.
Problem reported by Steve Kemp (Bug#27585).
* src/eval.c (near_C_stack_top): Remove. All uses replaced
by current_thread->stack_top.
(record_in_backtrace): Set current_thread->stack_top.
This is for when the Lisp interpreter calls itself.
* src/lread.c (read1): Set current_thread->stack_top.
This is for recursive s-expression reads.
* src/print.c (print_object): Set current_thread->stack_top.
This is for recursive s-expression printing.
* src/thread.c (mark_one_thread): Get stack top first.
* src/thread.h (struct thread_state.stack_top): Now void *, not char *.
* src/thread.c (lisp_mutex_lock_for_thread): New function,
with all the guts of lisp_mutex_lock.
(lisp_mutex_lock): Call lisp_mutex_lock_for_thread.
(condition_wait_callback): Don't call post_acquire_global_lock
before locking the mutex, as that could cause a signaled thread to
exit prematurely, because the condvar's mutex is recorded to be
not owned by any thread, and with-mutex wants to unlock it as part
of unwinding the stack in response to the signal.
* src/thread.c (last_thread_error): New static variable.
(syms_of_threads): Staticpro it.
(record_thread_error, Fthread_last_error): New functions.
(syms_of_threads): Defsubr Fthread_last_error.
* doc/lispref/threads.texi (Basic Thread Functions): Document
thread-last-error.
* test/src/thread-tests.el (thread-errors, thread-signal-early)
(threads-condvar-wait): Test the values returned by
thread-last-error.
* src/thread.c (lisp_mutex_lock, lisp_mutex_unlock)
(lisp_mutex_unlock_for_wait, condition_wait_callback)
(condition_notify_callback): Improve commentary.
(condition_wait_callback): Call post_acquire_global_lock before
attempting to lock the mutex, to make sure the lock's owner is
recorded correctly.
* test/src/thread-tests.el (threads-condvar-wait): New test.
This avoids the confusion of using two different phrases "main thread"
and "primary thread" internally to mean the same thing. See:
http://lists.gnu.org/archive/html/emacs-devel/2016-12/msg01142.html
* src/thread.c (main_thread): Rename from primary_thread,
since the new name no longer clashes with main_thread_id
and Emacs internals normally call this the "main thread".
(init_main_thread): Rename from init_primary_thread.
(main_thread_p): Rename from primary_thread_p.
All uses changed.
This improves performance overall on my benchmark on x86-64,
since the interpreted program-counter resides in a machine
register rather than in RAM.
* etc/DEBUG, src/.gdbinit: Remove xbytecode GDB command, as there
is no longer a byte stack to decode.
* src/bytecode.c (struct byte_stack, byte_stack_list)
(relocate_byte_stack): Remove. All uses removed.
(FETCH): Simplify now that pc is now local (typically, in a
register) and no longer needs to be relocated.
(CHECK_RANGE): Remove. All uses now done inline, in a different way.
(BYTE_CODE_QUIT): Remove; now done by op_relative_branch.
(exec_byte_code): Allocate a copy of the function’s bytecode,
so that there is no problem if GC moves it.
* src/lisp.h (struct handler): Remove byte_stack member.
All uses removed.
* src/thread.c (unmark_threads): Remove. All uses removed.
* src/thread.h (struct thread_state): Remove m_byte_stack_list member.
All uses removed. m_stack_bottom is now the first non-Lisp field.
* src/thread.h (struct thread_state): New member not_holding_lock.
(maybe_reacquire_global_lock): Add prototype.
* src/thread.c: Include syssignal.h.
(maybe_reacquire_global_lock): New function.
(really_call_select): Set the not_holding_lock member of the
thread state before releasing the lock, and rest it after
re-acquiring the lock when the select function returns. Block
SIGINT while doing this to make sure we are not interrupted on TTY
frames.
* src/sysdep.c (block_interrupt_signal, restore_signal_mask): New
functions.
* src/syssignal.h (block_interrupt_signal, restore_signal_mask):
Add prototypes.
* src/keyboard.c (read_char) [THREADS_ENABLED]: Call
maybe_reacquire_global_lock. (Bug#25178)
* src/thread.c (post_acquire_global_lock): Don't raise the pending
signal if the thread's handlers were not yet set up, as that will
cause Emacs to exit with a fatal error. This can happen if a
thread is signaled as soon as make-thread returns, before the new
thread had an opportunity to acquire the global lock, set up the
handlers, and call the thread function.
* test/src/thread-tests.el (thread-signal-early): New test.
* src/thread.c (post_acquire_global_lock): Call
set_buffer_internal_2 instead of tricking set_buffer_internal_1
into resetting the current buffer even if it didn't change. This
avoids bug#25165, caused by failing to record the modified values
of point and mark, because current_buffer was set to NULL. Also,
don't bother re-setting the buffer if there was no thread switch,
as that just wastes cycles.
* src/buffer.c (set_buffer_internal_2): New function, with most of
the body of set_buffer_internal_1, but without the test for B
being identical to the current buffer.
(set_buffer_internal_1): Call set_buffer_internal_2 if B is not
identical to the current buffer.
* src/buffer.h (set_buffer_internal_2): Add prototype.
* test/src/thread-tests.el (thread-sticky-point): New test.
* src/thread.c (mark_one_thread): Use NILP to compare with
m_saved_last_thing_searched, which is a Lisp object. Reported by
Andreas Politz <politza@hochschule-trier.de>.
src/eval.c (unbind_for_thread_switch): Accept a 'struct
thread_state *' argument and use specpdl_ptr and specpdl of that
thread. Fixes crashes if find_symbol_value signals an error.
src/thread.c (post_acquire_global_lock): Update current_thread
before calling unbind_for_thread_switch. Pass the previous thread
to unbind_for_thread_switch.
This introduces the thread_alive_p macro and changes
thread-alive-p to use it. This is a minor cleanup.
It also changes all-threads to ignore dead threads.
* we called unbind_for_thread_switch unconditionally, but this
is wrong if the previous thread exited
* likewise, exiting a thread should clear current_thread
* redundant assignment in run_thread
* clean up init_threads - no need to re-init the primary thread
This patch still sometimes causes weird hangs in "make check".
However, I think that is a kernel bug, since Emacs enters the zombie
state but its parent process hangs in wait. This shouldn't happen.
