From 080363310650c93ad8e93018bcb6760ba5d32d1c Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Thu, 22 Nov 2018 16:09:14 +0000 Subject: Per-inferior thread list, thread ranges/iterators, down with ALL_THREADS, etc. As preparation for multi-target, this patch makes each inferior have its own thread list. This isn't absolutely necessary for multi-target, but simplifies things. It originally stemmed from the desire to eliminate the init_thread_list calls sprinkled around, plus it makes it more efficient to iterate over threads of a given inferior (no need to always iterate over threads of all inferiors). We still need to iterate over threads of all inferiors in a number of places, which means we'd need adjust the ALL_THREADS / ALL_NON_EXITED_THREADS macros. However, naively tweaking those macros to have an extra for loop, like: #define ALL_THREADS (thr, inf) \ for (inf = inferior_list; inf; inf = inf->next) \ for (thr = inf->thread_list; thr; thr = thr->next) causes problems with code that does "break" or "continue" within the ALL_THREADS loop body. Plus, we need to declare the extra "inf" local variable in order to pass it as temporary variable to ALL_THREADS (etc.) It gets even trickier when we consider extending the macros to filter out threads matching a ptid_t and a target. The macros become tricker to read/write. Been there. An alternative (which was my next attempt), is to replace the ALL_THREADS etc. iteration style with for_each_all_threads, for_each_non_exited_threads, etc. functions which would take a callback as parameter, which would usually be passed a lambda. However, I did not find that satisfactory at all, because the resulting code ends up a little less natural / more noisy to read, write and debug/step-through (due to use of lambdas), and in many places where we use "continue;" to skip to the next thread now need to use "return;". (I ran into hard to debug bugs caused by a continue/return confusion.) I.e., before: ALL_NON_EXITED_THREADS (tp) { if (tp->not_what_I_want) continue; // do something } would turn into: for_each_non_exited_thread ([&] (thread_info *tp) { if (tp->not_what_I_want) return; // do something }); Lastly, the solution I settled with was to replace the ALL_THREADS / ALL_NON_EXITED_THREADS / ALL_INFERIORS macros with (C++20-like) ranges and iterators, such that you can instead naturaly iterate over threads/inferiors using range-for, like e.g,.: // all threads, including THREAD_EXITED threads. for (thread_info *tp : all_threads ()) { .... } // all non-exited threads. for (thread_info *tp : all_non_exited_threads ()) { .... } // all non-exited threads of INF inferior. for (thread_info *tp : inf->non_exited_threads ()) { .... } The all_non_exited_threads() function takes an optional filter ptid_t as parameter, which is quite convenient when we need to iterate over threads matching that filter. See e.g., how the set_executing/set_stop_requested/finish_thread_state etc. functions in thread.c end up being simplified. Most of the patch thus is about adding the infrustructure for allowing the above. Later on when we get to actual multi-target, these functions/ranges/iterators will gain a "target_ops *" parameter so that e.g., we can iterate over all threads of a given target that match a given filter ptid_t. The only entry points users needs to be aware of are the all_threads/all_non_exited_threads etc. functions seen above. Thus, those functions are declared in gdbthread.h/inferior.h. The actual iterators/ranges are mainly "internals" and thus are put out of view in the new thread-iter.h/thread-iter.c/inferior-iter.h files. That keeps the gdbthread.h/inferior.h headers quite a bit more readable. A common/safe-iterator.h header is added which adds a template that can be used to build "safe" iterators, which are forward iterators that can be used to replace the ALL_THREADS_SAFE macro and other instances of the same idiom in future. There's a little bit of shuffling of code between gdbthread.h/thread.c/inferior.h in the patch. That is necessary in order to avoid circular dependencies between the gdbthread.h/inferior.h headers. As for the init_thread_list calls sprinkled around, they're all eliminated by this patch, and a new, central call is added to inferior_appeared. Note how also related to that, there's a call to init_wait_for_inferior in remote.c that is eliminated. init_wait_for_inferior is currently responsible for discarding skipped inline frames, which had to be moved elsewhere. Given that nowadays we always have a thread even for single-threaded processes, the natural place is to delete a frame's inline frame info when we delete the thread. I.e., from clear_thread_inferior_resources. gdb/ChangeLog: 2018-11-22 Pedro Alves * Makefile.in (COMMON_SFILES): Add thread-iter.c. * breakpoint.c (breakpoints_should_be_inserted_now): Replace ALL_NON_EXITED_THREADS with all_non_exited_threads. (print_one_breakpoint_location): Replace ALL_INFERIORS with all_inferiors. * bsd-kvm.c: Include inferior.h. * btrace.c (btrace_free_objfile): Replace ALL_NON_EXITED_THREADS with all_non_exited_threads. * common/filtered-iterator.h: New. * common/safe-iterator.h: New. * corelow.c (core_target_open): Don't call init_thread_list here. * darwin-nat.c (thread_info_from_private_thread_info): Replace ALL_THREADS with all_threads. * fbsd-nat.c (fbsd_nat_target::resume): Replace ALL_NON_EXITED_THREADS with inf->non_exited_threads. * fbsd-tdep.c (fbsd_make_corefile_notes): Replace ALL_NON_EXITED_THREADS with inf->non_exited_threads. * fork-child.c (postfork_hook): Don't call init_thread_list here. * gdbarch-selftests.c (register_to_value_test): Adjust. * gdbthread.h: Don't include "inferior.h" here. (struct inferior): Forward declare. (enum step_over_calls_kind): Moved here from inferior.h. (thread_info::deletable): Definition moved to thread.c. (find_thread_ptid (inferior *, ptid_t)): Declare. (ALL_THREADS, ALL_THREADS_BY_INFERIOR, ALL_THREADS_SAFE): Delete. Include "thread-iter.h". (all_threads, all_non_exited_threads, all_threads_safe): New. (any_thread_p): Declare. (thread_list): Delete. * infcmd.c (signal_command): Replace ALL_NON_EXITED_THREADS with all_non_exited_threads. (proceed_after_attach_callback): Delete. (proceed_after_attach): Take an inferior pointer instead of an integer PID. Adjust to use range-for. (attach_post_wait): Pass down inferior pointer instead of pid. Use range-for instead of ALL_NON_EXITED_THREADS. (detach_command): Remove init_thread_list call. * inferior-iter.h: New. * inferior.c (struct delete_thread_of_inferior_arg): Delete. (delete_thread_of_inferior): Delete. (delete_inferior, exit_inferior_1): Use range-for with inf->threads_safe() instead of iterate_over_threads. (inferior_appeared): Call init_thread_list here. (discard_all_inferiors): Use all_non_exited_inferiors. (find_inferior_id, find_inferior_pid): Use all_inferiors. (iterate_over_inferiors): Use all_inferiors_safe. (have_inferiors, number_of_live_inferiors): Use all_non_exited_inferiors. (number_of_inferiors): Use all_inferiors and std::distance. (print_inferior): Use all_inferiors. * inferior.h: Include gdbthread.h. (enum step_over_calls_kind): Moved to gdbthread.h. (struct inferior) : New field. : New methods. (ALL_INFERIORS): Delete. Include "inferior-iter.h". (ALL_NON_EXITED_INFERIORS): Delete. (all_inferiors_safe, all_inferiors, all_non_exited_inferiors): New functions. * inflow.c (child_interrupt, child_pass_ctrlc): Replace ALL_NON_EXITED_THREADS with all_non_exited_threads. * infrun.c (follow_exec): Use all_threads_safe. (clear_proceed_status, proceed): Use all_non_exited_threads. (init_wait_for_inferior): Don't clear inline frame state here. (infrun_thread_stop_requested, for_each_just_stopped_thread): Use all_threads instead of ALL_NON_EXITED_THREADS. (random_pending_event_thread): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. Use a lambda for repeated code. (clean_up_just_stopped_threads_fsms): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. (handle_no_resumed): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. Use all_inferiors instead of ALL_INFERIORS. (restart_threads, switch_back_to_stepped_thread): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. * linux-nat.c (check_zombie_leaders): Replace ALL_INFERIORS with all_inferiors. (kill_unfollowed_fork_children): Use inf->non_exited_threads instead of ALL_NON_EXITED_THREADS. * linux-tdep.c (linux_make_corefile_notes): Use inf->non_exited_threads instead of ALL_NON_EXITED_THREADS. * linux-thread-db.c (thread_db_target::update_thread_list): Replace ALL_INFERIORS with all_inferiors. (thread_db_target::thread_handle_to_thread_info): Use inf->non_exited_threads instead of ALL_NON_EXITED_THREADS. * mi/mi-interp.c (multiple_inferiors_p): New. (mi_on_resume_1): Simplify using all_non_exited_threads and multiple_inferiors_p. * mi/mi-main.c (mi_cmd_thread_list_ids): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. * nto-procfs.c (nto_procfs_target::open): Don't call init_thread_list here. * record-btrace.c (record_btrace_target_open) (record_btrace_target::stop_recording) (record_btrace_target::close) (record_btrace_target::record_is_replaying) (record_btrace_target::resume, record_btrace_target::wait) (record_btrace_target::record_stop_replaying): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. * record-full.c (record_full_wait_1): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. * regcache.c (cooked_read_test): Remove reference to global thread_list. * remote-sim.c (gdbsim_target::create_inferior): Don't call init_thread_list here. * remote.c (remote_target::update_thread_list): Use all_threads_safe instead of ALL_NON_EXITED_THREADS. (remote_target::process_initial_stop_replies): Replace ALL_INFERIORS with all_non_exited_inferiors and use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. (remote_target::open_1): Don't call init_thread_list here. (remote_target::append_pending_thread_resumptions) (remote_target::remote_resume_with_hc): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. (remote_target::commit_resume) (remote_target::remove_new_fork_children): Replace ALL_INFERIORS with all_non_exited_inferiors and use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. (remote_target::kill_new_fork_children): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. Remove init_thread_list and init_wait_for_inferior calls. (remote_target::remote_btrace_maybe_reopen) (remote_target::thread_handle_to_thread_info): Use all_non_exited_threads instead of ALL_NON_EXITED_THREADS. * target.c (target_terminal::restore_inferior) (target_terminal_is_ours_kind): Replace ALL_INFERIORS with all_non_exited_inferiors. * thread-iter.c: New file. * thread-iter.h: New file. * thread.c: Include "inline-frame.h". (thread_list): Delete. (clear_thread_inferior_resources): Call clear_inline_frame_state. (init_thread_list): Use all_threads_safe instead of ALL_THREADS_SAFE. Adjust to per-inferior thread lists. (new_thread): Adjust to per-inferior thread lists. (add_thread_silent): Pass inferior to find_thread_ptid. (thread_info::deletable): New, moved from the header. (delete_thread_1): Adjust to per-inferior thread lists. (find_thread_global_id): Use inf->threads(). (find_thread_ptid): Use find_inferior_ptid and pass inferior to find_thread_ptid. (find_thread_ptid(inferior*, ptid_t)): New overload. (iterate_over_threads): Use all_threads_safe. (any_thread_p): New. (thread_count): Use all_threads and std::distance. (live_threads_count): Use all_non_exited_threads and std::distance. (valid_global_thread_id): Use all_threads. (in_thread_list): Use find_thread_ptid. (first_thread_of_inferior): Adjust to per-inferior thread lists. (any_thread_of_inferior, any_live_thread_of_inferior): Use inf->non_exited_threads(). (prune_threads, delete_exited_threads): Use all_threads_safe. (thread_change_ptid): Pass inferior pointer to find_thread_ptid. (set_resumed, set_running): Use all_non_exited_threads. (is_thread_state, is_stopped, is_exited, is_running) (is_executing): Delete. (set_executing, set_stop_requested, finish_thread_state): Use all_non_exited_threads. (print_thread_info_1): Use all_inferiors and all_threads. (thread_apply_all_command): Use all_non_exited_threads. (thread_find_command): Use all_threads. (update_threads_executing): Use all_non_exited_threads. * tid-parse.c (parse_thread_id): Use inf->threads. * x86-bsd-nat.c (x86bsd_dr_set): Use inf->non_exited_threads (). --- gdb/inferior.h | 91 ++++++++++++++++++++++++++++++++++++++++++++++------------ 1 file changed, 73 insertions(+), 18 deletions(-) (limited to 'gdb/inferior.h') diff --git a/gdb/inferior.h b/gdb/inferior.h index af5e920..33c2eac 100644 --- a/gdb/inferior.h +++ b/gdb/inferior.h @@ -53,6 +53,7 @@ struct thread_info; #include "common/refcounted-object.h" #include "common-inferior.h" +#include "gdbthread.h" struct infcall_suspend_state; struct infcall_control_state; @@ -245,17 +246,6 @@ extern int stopped_by_random_signal; `set print inferior-events'. */ extern int print_inferior_events; -/* STEP_OVER_ALL means step over all subroutine calls. - STEP_OVER_UNDEBUGGABLE means step over calls to undebuggable functions. - STEP_OVER_NONE means don't step over any subroutine calls. */ - -enum step_over_calls_kind - { - STEP_OVER_NONE, - STEP_OVER_ALL, - STEP_OVER_UNDEBUGGABLE - }; - /* Anything but NO_STOP_QUIETLY means we expect a trap and the caller will handle it themselves. STOP_QUIETLY is used when running in the shell before the child program has been exec'd and when running @@ -360,6 +350,38 @@ public: /* Pointer to next inferior in singly-linked list of inferiors. */ struct inferior *next = NULL; + /* This inferior's thread list. */ + thread_info *thread_list = nullptr; + + /* Returns a range adapter covering the inferior's threads, + including exited threads. Used like this: + + for (thread_info *thr : inf->threads ()) + { .... } + */ + inf_threads_range threads () + { return inf_threads_range (this->thread_list); } + + /* Returns a range adapter covering the inferior's non-exited + threads. Used like this: + + for (thread_info *thr : inf->non_exited_threads ()) + { .... } + */ + inf_non_exited_threads_range non_exited_threads () + { return inf_non_exited_threads_range (this->thread_list); } + + /* Like inferior::threads(), but returns a range adapter that can be + used with range-for, safely. I.e., it is safe to delete the + currently-iterated thread, like this: + + for (thread_info *t : inf->threads_safe ()) + if (some_condition ()) + delete f; + */ + inline safe_inf_threads_range threads_safe () + { return safe_inf_threads_range (this->thread_list); } + /* Convenient handle (GDB inferior id). Unique across all inferiors. */ int num = 0; @@ -575,16 +597,49 @@ private: /* Traverse all inferiors. */ -#define ALL_INFERIORS(I) \ - for ((I) = inferior_list; (I); (I) = (I)->next) +extern struct inferior *inferior_list; -/* Traverse all non-exited inferiors. */ +/* Pull in the internals of the inferiors ranges and iterators. Must + be done after struct inferior is defined. */ +#include "inferior-iter.h" -#define ALL_NON_EXITED_INFERIORS(I) \ - ALL_INFERIORS (I) \ - if ((I)->pid != 0) +/* Return a range that can be used to walk over all inferiors + inferiors, with range-for, safely. I.e., it is safe to delete the + currently-iterated inferior. When combined with range-for, this + allow convenient patterns like this: -extern struct inferior *inferior_list; + for (inferior *inf : all_inferiors_safe ()) + if (some_condition ()) + delete inf; +*/ + +inline all_inferiors_safe_range +all_inferiors_safe () +{ + return {}; +} + +/* Returns a range representing all inferiors, suitable to use with + range-for, like this: + + for (inferior *inf : all_inferiors ()) + [...] +*/ + +inline all_inferiors_range +all_inferiors () +{ + return {}; +} + +/* Return a range that can be used to walk over all inferiors with PID + not zero, with range-for. */ + +inline all_non_exited_inferiors_range +all_non_exited_inferiors () +{ + return {}; +} /* Prune away automatically added inferiors that aren't required anymore. */ -- cgit v1.1