From a0a031bce0527b1521788b5dad640e7883b3a252 Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Fri, 8 Sep 2023 15:44:40 +0100 Subject: [PATCH] gdb: remove one user of the executable changed observer My goal for the next few commits is to expose the executable_changed observable from the Python API. However, there is call to the executable_changed observable in the reread_symbols function (in symfile.c), and this doesn't actually correspond to the executable changing. My idea then, is to remove this use of the executable_changed observable, but, before I can do that, I need to check that nothing is going to break, and that requires my to think about the current users of this observable. One current user of executable_changed is in symtab.c. We add an executable_changed observer that calls: set_main_name (nullptr, language_unknown); to discard all information about the main function when the executable changes. However, changing the executable doesn't actually change the debug information. The debug information changes when the symbol-file changes, so I think this observer is in slightly the wrong place. The new_objfile observable is (unfortunately) overloaded, it is called when a new objfile is loaded, and also (when its argument is nullptr), when all debug information should be discarded. It turns out that there is already a new_objfile observer in symtab.c. I propose that, when the argument is nullptr (indicating all debug info should be discarded), that we should call set_main_name to discard the information about the main function. We can then remove the executable_changed observer from symtab.c. All tests still pass, and, in my local world, I added some debug printf calls, and I think we are still discarded the main information everywhere we need to. Approved-By: Tom Tromey --- gdb/symtab.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) diff --git a/gdb/symtab.c b/gdb/symtab.c index 66d073e3b7b..e399dd81d81 100644 --- a/gdb/symtab.c +++ b/gdb/symtab.c @@ -100,6 +100,8 @@ static struct block_symbol enum block_enum block_index, const char *name, const domain_enum domain); +static void set_main_name (const char *name, enum language lang); + /* Type of the data stored on the program space. */ struct main_info @@ -1694,6 +1696,11 @@ symtab_new_objfile_observer (struct objfile *objfile) { /* Ideally we'd use OBJFILE->pspace, but OBJFILE may be NULL. */ symbol_cache_flush (current_program_space); + + /* When all objfiles have been removed (OBJFILE is nullptr), then forget + everything we know about the main function. */ + if (objfile == nullptr) + set_main_name (nullptr, language_unknown); } /* This module's 'free_objfile' observer. */ @@ -6329,15 +6336,6 @@ main_language (void) return info->language_of_main; } -/* Handle ``executable_changed'' events for the symtab module. */ - -static void -symtab_observer_executable_changed (void) -{ - /* NAME_OF_MAIN may no longer be the same, so reset it for now. */ - set_main_name (NULL, language_unknown); -} - /* Return 1 if the supplied producer string matches the ARM RealView compiler (armcc). */ @@ -7020,8 +7018,6 @@ the use of prologue scanners."), class_maintenance, 0, &maintenancelist); deprecate_cmd (c, "maintenancelist flush symbol-cache"); - gdb::observers::executable_changed.attach (symtab_observer_executable_changed, - "symtab"); gdb::observers::new_objfile.attach (symtab_new_objfile_observer, "symtab"); gdb::observers::free_objfile.attach (symtab_free_objfile_observer, "symtab"); } -- 2.30.2