When one presses <tab> at the "wrong" time it can feel like gdb stalls. It would be nice if gdb gave some feedback it is doing lots of lookups. Example from a c++ program: (gdb) break std::<tab> [...nothing for about 3 seconds - not obviously killable...] Display all 14472 possibilities? (y or n)
See also bug 15548.
Maybe it's difficult to resolve thoroughly, as the problem is the amount of symbol tables and not amount of symbols (so it can happen with vastly varying amount of symbols). But for the meantime, can we have an option to disable the tab completion when the inputted prefix is < $SOME_NUM? e.g. if I enter the command "noshorttab" and do "b foo<tab>" nothing will happen.
The master branch has been updated by Doug Evans <devans@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=ef0b411a110cd2602cb89c3fb237baf8beb28545 commit ef0b411a110cd2602cb89c3fb237baf8beb28545 Author: Gary Benson <gbenson@redhat.com> Date: Sat Jan 31 15:07:22 2015 -0800 Add max-completions parameter, and implement tab-completion limiting. This commit adds a new exception, MAX_COMPLETIONS_REACHED_ERROR, to be thrown whenever the completer has generated too many candidates to be useful. A new user-settable variable, "max_completions", is added to control this behaviour. A top-level completion limit is added to complete_line_internal, as the final check to ensure the user never sees too many completions. An additional limit is added to default_make_symbol_completion_list_break_on, to halt time-consuming symbol table expansions. gdb/ChangeLog: PR cli/9007 PR cli/11920 PR cli/15548 * cli/cli-cmds.c (complete_command): Notify user if max-completions reached. * common/common-exceptions.h (enum errors) <MAX_COMPLETIONS_REACHED_ERROR>: New value. * completer.h (get_max_completions_reached_message): New declaration. (max_completions): Likewise. (completion_tracker_t): New typedef. (new_completion_tracker): New declaration. (make_cleanup_free_completion_tracker): Likewise. (maybe_add_completion_enum): New enum. (maybe_add_completion): New declaration. (throw_max_completions_reached_error): Likewise. * completer.c (max_completions): New global variable. (new_completion_tracker): New function. (free_completion_tracker): Likewise. (make_cleanup_free_completion_tracker): Likewise. (maybe_add_completions): Likewise. (throw_max_completions_reached_error): Likewise. (complete_line): Remove duplicates and limit result to max_completions entries. (get_max_completions_reached_message): New function. (gdb_display_match_list): Handle max_completions. (_initialize_completer): New declaration and function. * symtab.c: Include completer.h. (completion_tracker): New static variable. (completion_list_add_name): Call maybe_add_completion. (default_make_symbol_completion_list_break_on_1): Renamed from default_make_symbol_completion_list_break_on. Maintain completion_tracker across calls to completion_list_add_name. (default_make_symbol_completion_list_break_on): New function. * top.c (init_main): Set rl_completion_display_matches_hook. * tui/tui-io.c: Include completer.h. (tui_old_rl_display_matches_hook): New static global. (tui_rl_display_match_list): Notify user if max-completions reached. (tui_setup_io): Save/restore rl_completion_display_matches_hook. * NEWS (New Options): Mention set/show max-completions. gdb/doc/ChangeLog: * gdb.texinfo (Command Completion): Document new "set/show max-completions" option. gdb/testsuite/ChangeLog: * gdb.base/completion.exp: Disable completion limiting for existing tests. Add new tests to check completion limiting. * gdb.linespec/ls-errs.exp: Disable completion limiting.
The master branch has been updated by Doug Evans <devans@sourceware.org>: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=cfb069a8bebfacaf00dee6446e86a856978670be commit cfb069a8bebfacaf00dee6446e86a856978670be Author: Gary Benson <gbenson@redhat.com> Date: Sat Jan 31 15:24:26 2015 -0800 ChangeLog entries for max-completions patch. gdb/ChangeLog: PR cli/9007 PR cli/11920 PR cli/15548 * cli/cli-cmds.c (complete_command): Notify user if max-completions reached. * common/common-exceptions.h (enum errors) <MAX_COMPLETIONS_REACHED_ERROR>: New value. * completer.h (get_max_completions_reached_message): New declaration. (max_completions): Likewise. (completion_tracker_t): New typedef. (new_completion_tracker): New declaration. (make_cleanup_free_completion_tracker): Likewise. (maybe_add_completion_enum): New enum. (maybe_add_completion): New declaration. (throw_max_completions_reached_error): Likewise. * completer.c (max_completions): New global variable. (new_completion_tracker): New function. (free_completion_tracker): Likewise. (make_cleanup_free_completion_tracker): Likewise. (maybe_add_completions): Likewise. (throw_max_completions_reached_error): Likewise. (complete_line): Remove duplicates and limit result to max_completions entries. (get_max_completions_reached_message): New function. (gdb_display_match_list): Handle max_completions. (_initialize_completer): New declaration and function. * symtab.c: Include completer.h. (completion_tracker): New static variable. (completion_list_add_name): Call maybe_add_completion. (default_make_symbol_completion_list_break_on_1): Renamed from default_make_symbol_completion_list_break_on. Maintain completion_tracker across calls to completion_list_add_name. (default_make_symbol_completion_list_break_on): New function. * top.c (init_main): Set rl_completion_display_matches_hook. * tui/tui-io.c: Include completer.h. (tui_old_rl_display_matches_hook): New static global. (tui_rl_display_match_list): Notify user if max-completions reached. (tui_setup_io): Save/restore rl_completion_display_matches_hook. * NEWS (New Options): Mention set/show max-completions. gdb/doc/ChangeLog: * gdb.texinfo (Command Completion): Document new "set/show max-completions" option. gdb/testsuite/ChangeLog: * gdb.base/completion.exp: Disable completion limiting for existing tests. Add new tests to check completion limiting. * gdb.linespec/ls-errs.exp: Disable completion limiting.
Patch committed.