This is more preparation bits for multi-target support.
In a multi-target scenario, we need to address the case of different
processes/threads running on different targets that happen to have the
same PID/PTID. E.g., we can have both process 123 in target 1, and
process 123 in target 2, while they're in reality different processes
running on different machines. Or maybe we've loaded multiple
instances of the same core file. Etc.
To address this, in my WIP multi-target branch, threads and processes
are uniquely identified by the (process_stratum target_ops *, ptid_t)
and (process_stratum target_ops *, pid) tuples respectively. I.e.,
each process_stratum instance has its own thread/process number space.
As you can imagine, that requires passing around target_ops * pointers
in a number of functions where we're currently passing only a ptid_t
or an int. E.g., when we look up a thread_info object by ptid_t in
find_thread_ptid, the ptid_t alone isn't sufficient.
In many cases though, we already have the thread_info or inferior
pointer handy, but we "lose" it somewhere along the call stack, only
to look it up again by ptid_t/pid. Since thread_info or inferior
objects know their parent target, if we pass around thread_info or
inferior pointers when possible, we avoid having to add extra
target_ops parameters to many functions, and also, we eliminate a
number of by ptid_t/int lookups.
So that's what this patch does. In a bit more detail:
- Changes a number of functions and methods to take a thread_info or
inferior pointer instead of a ptid_t or int parameter.
- Changes a number of structure fields from ptid_t/int to inferior or
thread_info pointers.
- Uses the inferior_thread() function whenever possible instead of
inferior_ptid.
- Uses thread_info pointers directly when possible instead of the
is_running/is_stopped etc. routines that require a lookup.
- A number of functions are eliminated along the way, such as:
int valid_gdb_inferior_id (int num);
int pid_to_gdb_inferior_id (int pid);
int gdb_inferior_id_to_pid (int num);
int in_inferior_list (int pid);
- A few structures and places hold a thread_info pointer across
inferior execution, so now they take a strong reference to the
(refcounted) thread_info object to avoid the thread_info pointer
getting stale. This is done in enable_thread_stack_temporaries and
in the infcall.c code.
- Related, there's a spot in infcall.c where using a RAII object to
handle the refcount would be handy, so a gdb::ref_ptr specialization
for thread_info is added (thread_info_ref, in gdbthread.h), along
with a gdb_ref_ptr policy that works for all refcounted_object types
(in common/refcounted-object.h).
gdb/ChangeLog:
2018-06-21 Pedro Alves <palves@redhat.com>
* ada-lang.h (ada_get_task_number): Take a thread_info pointer
instead of a ptid_t. All callers adjusted.
* ada-tasks.c (ada_get_task_number): Likewise. All callers
adjusted.
(print_ada_task_info, display_current_task_id, task_command_1):
Adjust.
* breakpoint.c (watchpoint_in_thread_scope): Adjust to use
inferior_thread.
(breakpoint_kind): Adjust.
(remove_breakpoints_pid): Rename to ...
(remove_breakpoints_inf): ... this. Adjust to take an inferior
pointer. All callers adjusted.
(bpstat_clear_actions): Use inferior_thread.
(get_bpstat_thread): New.
(bpstat_do_actions): Use it.
(bpstat_check_breakpoint_conditions, bpstat_stop_status): Adjust
to take a thread_info pointer. All callers adjusted.
(set_longjmp_breakpoint_for_call_dummy, set_momentary_breakpoint)
(breakpoint_re_set_thread): Use inferior_thread.
* breakpoint.h (struct inferior): Forward declare.
(bpstat_stop_status): Update.
(remove_breakpoints_pid): Delete.
(remove_breakpoints_inf): New.
* bsd-uthread.c (bsd_uthread_target::wait)
(bsd_uthread_target::update_thread_list): Use find_thread_ptid.
* btrace.c (btrace_add_pc, btrace_enable, btrace_fetch)
(maint_btrace_packet_history_cmd)
(maint_btrace_clear_packet_history_cmd): Adjust.
(maint_btrace_clear_cmd, maint_info_btrace_cmd): Adjust to use
inferior_thread.
* cli/cli-interp.c: Include "inferior.h".
* common/refcounted-object.h (struct
refcounted_object_ref_policy): New.
* compile/compile-object-load.c: Include gdbthread.h.
(store_regs): Use inferior_thread.
* corelow.c (core_target::close): Use current_inferior.
(core_target_open): Adjust to use first_thread_of_inferior and use
the current inferior.
* ctf.c (ctf_target::close): Adjust to use current_inferior.
* dummy-frame.c (dummy_frame_id) <ptid>: Delete, replaced by ...
<thread>: ... this new field. All references adjusted.
(dummy_frame_pop, dummy_frame_discard, register_dummy_frame_dtor):
Take a thread_info pointer instead of a ptid_t.
* dummy-frame.h (dummy_frame_push, dummy_frame_pop)
(dummy_frame_discard, register_dummy_frame_dtor): Take a
thread_info pointer instead of a ptid_t.
* elfread.c: Include "inferior.h".
(elf_gnu_ifunc_resolver_stop, elf_gnu_ifunc_resolver_return_stop):
Use inferior_thread.
* eval.c (evaluate_subexp): Likewise.
* frame.c (frame_pop, has_stack_frames, find_frame_sal): Use
inferior_thread.
* gdb_proc_service.h (struct thread_info): Forward declare.
(struct ps_prochandle) <ptid>: Delete, replaced by ...
<thread>: ... this new field. All references adjusted.
* gdbarch.h, gdbarch.c: Regenerate.
* gdbarch.sh (get_syscall_number): Replace 'ptid' parameter with a
'thread' parameter. All implementations and callers adjusted.
* gdbthread.h (thread_info) <set_running>: New method.
(delete_thread, delete_thread_silent): Take a thread_info pointer
instead of a ptid.
(global_thread_id_to_ptid, ptid_to_global_thread_id): Delete.
(first_thread_of_process): Delete, replaced by ...
(first_thread_of_inferior): ... this new function. All callers
adjusted.
(any_live_thread_of_process): Delete, replaced by ...
(any_live_thread_of_inferior): ... this new function. All callers
adjusted.
(switch_to_thread, switch_to_no_thread): Declare.
(is_executing): Delete.
(enable_thread_stack_temporaries): Update comment.
<enable_thread_stack_temporaries>: Take a thread_info pointer
instead of a ptid_t. Incref the thread.
<~enable_thread_stack_temporaries>: Decref the thread.
<m_ptid>: Delete
<m_thr>: New.
(thread_stack_temporaries_enabled_p, push_thread_stack_temporary)
(get_last_thread_stack_temporary)
(value_in_thread_stack_temporaries, can_access_registers_thread):
Take a thread_info pointer instead of a ptid_t. All callers
adjusted.
* infcall.c (get_call_return_value): Use inferior_thread.
(run_inferior_call): Work with thread pointers instead of ptid_t.
(call_function_by_hand_dummy): Work with thread pointers instead
of ptid_t. Use thread_info_ref.
* infcmd.c (proceed_thread_callback): Access thread's state
directly.
(ensure_valid_thread, ensure_not_running): Use inferior_thread,
access thread's state directly.
(continue_command): Use inferior_thread.
(info_program_command): Use find_thread_ptid and access thread
state directly.
(proceed_after_attach_callback): Use thread state directly.
(notice_new_inferior): Take a thread_info pointer instead of a
ptid_t. All callers adjusted.
(exit_inferior): Take an inferior pointer instead of a pid. All
callers adjusted.
(exit_inferior_silent): New.
(detach_inferior): Delete.
(valid_gdb_inferior_id, pid_to_gdb_inferior_id)
(gdb_inferior_id_to_pid, in_inferior_list): Delete.
(detach_inferior_command, kill_inferior_command): Use
find_inferior_id instead of valid_gdb_inferior_id and
gdb_inferior_id_to_pid.
(inferior_command): Use inferior and thread pointers.
* inferior.h (struct thread_info): Forward declare.
(notice_new_inferior): Take a thread_info pointer instead of a
ptid_t. All callers adjusted.
(detach_inferior): Delete declaration.
(exit_inferior, exit_inferior_silent): Take an inferior pointer
instead of a pid. All callers adjusted.
(gdb_inferior_id_to_pid, pid_to_gdb_inferior_id, in_inferior_list)
(valid_gdb_inferior_id): Delete.
* infrun.c (follow_fork_inferior, proceed_after_vfork_done)
(handle_vfork_child_exec_or_exit, follow_exec): Adjust.
(struct displaced_step_inferior_state) <pid>: Delete, replaced by
...
<inf>: ... this new field.
<step_ptid>: Delete, replaced by ...
<step_thread>: ... this new field.
(get_displaced_stepping_state): Take an inferior pointer instead
of a pid. All callers adjusted.
(displaced_step_in_progress_any_inferior): Adjust.
(displaced_step_in_progress_thread): Take a thread pointer instead
of a ptid_t. All callers adjusted.
(displaced_step_in_progress, add_displaced_stepping_state): Take
an inferior pointer instead of a pid. All callers adjusted.
(get_displaced_step_closure_by_addr): Adjust.
(remove_displaced_stepping_state): Take an inferior pointer
instead of a pid. All callers adjusted.
(displaced_step_prepare_throw, displaced_step_prepare)
(displaced_step_fixup): Take a thread pointer instead of a ptid_t.
All callers adjusted.
(start_step_over): Adjust.
(infrun_thread_ptid_changed): Remove bit updating ptids in the
displaced step queue.
(do_target_resume): Adjust.
(fetch_inferior_event): Use inferior_thread.
(context_switch, get_inferior_stop_soon): Take an
execution_control_state pointer instead of a ptid_t. All callers
adjusted.
(switch_to_thread_cleanup): Delete.
(stop_all_threads): Use scoped_restore_current_thread.
* inline-frame.c: Include "gdbthread.h".
(inline_state) <inline_state>: Take a thread pointer instead of a
ptid_t. All callers adjusted.
<ptid>: Delete, replaced by ...
<thread>: ... this new field.
(find_inline_frame_state): Take a thread pointer instead of a
ptid_t. All callers adjusted.
(skip_inline_frames, step_into_inline_frame)
(inline_skipped_frames, inline_skipped_symbol): Take a thread
pointer instead of a ptid_t. All callers adjusted.
* inline-frame.h (skip_inline_frames, step_into_inline_frame)
(inline_skipped_frames, inline_skipped_symbol): Likewise.
* linux-fork.c (delete_checkpoint_command): Adjust to use thread
pointers directly.
* linux-nat.c (get_detach_signal): Likewise.
* linux-thread-db.c (thread_from_lwp): New 'stopped' parameter.
(thread_db_notice_clone): Adjust.
(thread_db_find_new_threads_silently)
(thread_db_find_new_threads_2, thread_db_find_new_threads_1): Take
a thread pointer instead of a ptid_t. All callers adjusted.
* mi/mi-cmd-var.c: Include "inferior.h".
(mi_cmd_var_update_iter): Update to use thread pointers.
* mi/mi-interp.c (mi_new_thread): Update to use the thread's
inferior directly.
(mi_output_running_pid, mi_inferior_count): Delete, bits factored
out to ...
(mi_output_running): ... this new function.
(mi_on_resume_1): Adjust to use it.
(mi_user_selected_context_changed): Adjust to use inferior_thread.
* mi/mi-main.c (proceed_thread): Adjust to use thread pointers
directly.
(interrupt_thread_callback): : Adjust to use thread and inferior
pointers.
* proc-service.c: Include "gdbthread.h".
(ps_pglobal_lookup): Adjust to use the thread's inferior directly.
* progspace-and-thread.c: Include "inferior.h".
* progspace.c: Include "inferior.h".
* python/py-exitedevent.c (create_exited_event_object): Adjust to
hold a reference to an inferior_object.
* python/py-finishbreakpoint.c (bpfinishpy_init): Adjust to use
inferior_thread.
* python/py-inferior.c (struct inferior_object): Give the type a
tag name instead of a typedef.
(python_on_normal_stop): No need to check if the current thread is
listed.
(inferior_to_inferior_object): Change return type to
inferior_object. All callers adjusted.
(find_thread_object): Delete, bits factored out to ...
(thread_to_thread_object): ... this new function.
* python/py-infthread.c (create_thread_object): Use
inferior_to_inferior_object.
(thpy_is_stopped): Use thread pointer directly.
(gdbpy_selected_thread): Use inferior_thread.
* python/py-record-btrace.c (btpy_list_object) <ptid>: Delete
field, replaced with ...
<thread>: ... this new field. All users adjusted.
(btpy_insn_or_gap_new): Drop const.
(btpy_list_new): Take a thread pointer instead of a ptid_t. All
callers adjusted.
* python/py-record.c: Include "gdbthread.h".
(recpy_insn_new, recpy_func_new): Take a thread pointer instead of
a ptid_t. All callers adjusted.
(gdbpy_current_recording): Use inferior_thread.
* python/py-record.h (recpy_record_object) <ptid>: Delete
field, replaced with ...
<thread>: ... this new field. All users adjusted.
(recpy_element_object) <ptid>: Delete
field, replaced with ...
<thread>: ... this new field. All users adjusted.
(recpy_insn_new, recpy_func_new): Take a thread pointer instead of
a ptid_t. All callers adjusted.
* python/py-threadevent.c: Include "gdbthread.h".
(get_event_thread): Use thread_to_thread_object.
* python/python-internal.h (struct inferior_object): Forward
declare.
(find_thread_object, find_inferior_object): Delete declarations.
(thread_to_thread_object, inferior_to_inferior_object): New
declarations.
* record-btrace.c: Include "inferior.h".
(require_btrace_thread): Use inferior_thread.
(record_btrace_frame_sniffer)
(record_btrace_tailcall_frame_sniffer): Use inferior_thread.
(get_thread_current_frame): Use scoped_restore_current_thread and
switch_to_thread.
(get_thread_current_frame): Use thread pointer directly.
(record_btrace_replay_at_breakpoint): Use thread's inferior
pointer directly.
* record-full.c: Include "inferior.h".
* regcache.c: Include "gdbthread.h".
(get_thread_arch_regcache): Use the inferior's address space
directly.
(get_thread_regcache, registers_changed_thread): New.
* regcache.h (get_thread_regcache(thread_info *thread)): New
overload.
(registers_changed_thread): New.
(remote_target) <remote_detach_1>: Swap order of parameters.
(remote_add_thread): <remote_add_thread>: Return the new thread.
(get_remote_thread_info(ptid_t)): New overload.
(remote_target::remote_notice_new_inferior): Use thread pointers
directly.
(remote_target::process_initial_stop_replies): Use
thread_info::set_running.
(remote_target::remote_detach_1, remote_target::detach)
(extended_remote_target::detach): Adjust.
* stack.c (frame_show_address): Use inferior_thread.
* target-debug.h (target_debug_print_thread_info_pp): New.
* target-delegates.c: Regenerate.
* target.c (default_thread_address_space): Delete.
(memory_xfer_partial_1): Use current_inferior.
(target_detach): Use current_inferior.
(target_thread_address_space): Delete.
(generic_mourn_inferior): Use current_inferior.
* target.h (struct target_ops) <thread_address_space>: Delete.
(target_thread_address_space): Delete.
* thread.c (init_thread_list): Use ALL_THREADS_SAFE. Use thread
pointers directly.
(delete_thread_1, delete_thread, delete_thread_silent): Take a
thread pointer instead of a ptid_t. Adjust all callers.
(ptid_to_global_thread_id, global_thread_id_to_ptid): Delete.
(first_thread_of_process): Delete, replaced by ...
(first_thread_of_inferior): ... this new function. All callers
adjusted.
(any_thread_of_process): Rename to ...
(any_thread_of_inferior): ... this, and take an inferior pointer.
(any_live_thread_of_process): Rename to ...
(any_live_thread_of_inferior): ... this, and take an inferior
pointer.
(thread_stack_temporaries_enabled_p, push_thread_stack_temporary)
(value_in_thread_stack_temporaries)
(get_last_thread_stack_temporary): Take a thread pointer instead
of a ptid_t. Adjust all callers.
(thread_info::set_running): New.
(validate_registers_access): Use inferior_thread.
(can_access_registers_ptid): Rename to ...
(can_access_registers_thread): ... this, and take a thread
pointer.
(print_thread_info_1): Adjust to compare thread pointers instead
of ptids.
(switch_to_no_thread, switch_to_thread): Make extern.
(scoped_restore_current_thread::~scoped_restore_current_thread):
Use m_thread pointer directly.
(scoped_restore_current_thread::scoped_restore_current_thread):
Use inferior_thread.
(thread_command): Use thread pointer directly.
(thread_num_make_value_helper): Use inferior_thread.
* top.c (execute_command): Use inferior_thread.
* tui/tui-interp.c: Include "inferior.h".
* varobj.c (varobj_create): Use inferior_thread.
(value_of_root_1): Use find_thread_global_id instead of
global_thread_id_to_ptid.
This patch fixes an internal error exposed by a test that does
something like:
define kill-and-remove
kill inferiors 2
remove-inferiors 2
end
# Start one inferior.
start
# Start another inferior.
add-inferior 2
inferior 2
start
# Kill and remove inferior 1 while inferior 2 is selected.
thread apply 1.1 kill-and-remove
The internal error looks like this:
Thread 1.1 (Thread 0x7ffff7fc2700 (LWP 20677)):
[Switching to inferior 1 [process 20677] (gdb/testsuite/outputs/gdb.threads/threadapply/threadapply)]
[Switching to thread 1.1 (Thread 0x7ffff7fc2700 (LWP 20677))]
#0 main () at src/gdb/testsuite/gdb.threads/threadapply.c:38
38 for (i = 0; i < NUM; i++)
src/gdb/inferior.c:66: internal-error: void set_current_inferior(inferior*): Assertion `inf != NULL' failed.
A problem internal to GDB has been detected,
further debugging may prove unreliable.
Quit this debugging session? (y or n) FAIL: gdb.threads/threadapply.exp: kill_and_remove_inferior: try kill-and-remove: thread apply 1.1 kill-and-remove (GDB internal error)
There are several problems around this area of the code. One is that
in do_restore_current_thread_cleanup, we do a look up of inferior by
ptid, which can find the wrong inferior if the previously selected
inferior exited and some other inferior was started with a reused pid
(rare, but still...).
The other problem is that the "remove-inferiors" command rejects
attempts to remove the current inferior, but when we get to
"remove-inferiors" in a "thread apply THR remove-inferiors 2" command,
the current inferior is the inferior of thread THR, not the previously
selected inferior, so if the previously selected inferior was inferior
2, that command still manages to wipe it, and then gdb restores the
old selected inferior, which is now a dangling pointer...
So the fix here is:
- Make make_cleanup_restore_current_thread store a pointer to the
previously selected inferior directly, and use it directly instead
of doing ptid look ups.
- Add a refcount to inferiors, very similar to thread_info's refcount,
that is incremented/decremented by
make_cleanup_restore_current_thread, and checked before deleting an
inferior. To avoid duplication, a new refcounted_object type is
added, that both thread_info and inferior inherit from.
gdb/ChangeLog:
2017-04-19 Pedro Alves <palves@redhat.com>
* common/refcounted-object.h: New file.
* gdbthread.h: Include "common/refcounted-object.h".
(thread_info): Inherit from refcounted_object and add comments.
(thread_info::incref, thread_info::decref)
(thread_info::m_refcount): Delete.
(thread_info::deletable): Use the refcounted_object::refcount()
method.
* inferior.c (current_inferior_): Add comment.
(set_current_inferior): Increment/decrement refcounts.
(prune_inferiors, remove_inferior_command): Skip inferiors marked
not-deletable instead of comparing with the current inferior.
(initialize_inferiors): Increment the initial inferior's refcount.
* inferior.h (struct inferior): Forward declare.
Include "common/refcounted-object.h".
(current_inferior, set_current_inferior): Move declaration to
before struct inferior's definition, and fix comment.
(inferior): Inherit from refcounted_object. Add comments.
* thread.c (switch_to_thread_no_regs): Reference the thread's
inferior pointer directly instead of doing a ptid lookup.
(switch_to_no_thread): New function.
(switch_to_thread(thread_info *)): New function, factored out
from ...
(switch_to_thread(ptid_t)): ... this.
(restore_current_thread): Delete.
(current_thread_cleanup): Remove 'inf_id' and 'was_removable'
fields, and add 'inf' field.
(do_restore_current_thread_cleanup): Check whether old->inf is
alive instead of looking up an inferior by ptid. Use
switch_to_thread and switch_to_no_thread.
(restore_current_thread_cleanup_dtor): Use old->inf directly
instead of lookup up an inferior by id. Decref the inferior.
Don't restore 'removable'.
(make_cleanup_restore_current_thread): Same the inferior pointer
in old, instead of the inferior number. Incref the inferior.
Don't save/clear 'removable'.
gdb/testsuite/ChangeLog:
2017-04-19 Pedro Alves <palves@redhat.com>
* gdb.threads/threadapply.exp (kill_and_remove_inferior): New
procedure.
(top level): Call it.
* lib/gdb.exp (gdb_define_cmd): New procedure.
Pedro Alves