From 19a2740f7f2ea0f65745a3c00cf8a64647378aa3 Mon Sep 17 00:00:00 2001 From: Andrew Burgess Date: Fri, 27 Dec 2019 18:31:09 +0000 Subject: gdb: Remove C++ symbol aliases from completion list Consider debugging the following C++ program: struct object { int a; }; typedef object *object_p; static int get_value (object_p obj) { return obj->a; } int main () { object obj; obj.a = 0; return get_value (&obj); } Now in a GDB session: (gdb) complete break get_value break get_value(object*) break get_value(object_p) Or: (gdb) break get_va (gdb) break get_value(object Function "get_value(object" not defined. Make breakpoint pending on future shared library load? (y or [n]) n The reason this happens is that we add completions based on the msymbol names and on the symbol names. For C++ both of these names include the parameter list, however, the msymbol names have some differences from the symbol names, for example: + typedefs are resolved, + whitespace rules are different around pointers, + the 'const' keyword is placed differently. What this means is that the msymbol names and symbol names appear to be completely different to GDB's completion tracker, and therefore to readline when it offers the completions. This commit builds on the previous commit which reworked the completion_tracker class. It is now trivial to add a remove_completion member function, this is then used along with cp_canonicalize_string_no_typedefs to remove the msymbol aliases from the completion tracker as we add the symbol names. Now, for the above program GDB only presents a single completion for 'get_value', which is 'get_value(object_p)'. It is still possible to reference the symbol using the msymbol name, so a user can manually type out 'break get_value (object *)' if they wish and will get the expected behaviour. I did consider adding an option to make this alias exclusion optional, in the end I didn't bother as I didn't think it would be very useful, but I can easily add such an option if people think it would be useful. gdb/ChangeLog: * completer.c (completion_tracker::remove_completion): Define new function. * completer.h (completion_tracker::remove_completion): Declare new function. * symtab.c (completion_list_add_symbol): Remove aliasing msymbols when adding a C++ function symbol. gdb/testsuite/ChangeLog: * gdb.linespec/cp-completion-aliases.cc: New file. * gdb.linespec/cp-completion-aliases.exp: New file. Change-Id: Ie5c7c9fc8ecf973072cfb4a9650867104bf7f50c --- gdb/testsuite/ChangeLog | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'gdb/testsuite/ChangeLog') diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog index 0588fe6..6574270e 100644 --- a/gdb/testsuite/ChangeLog +++ b/gdb/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2020-03-19 Andrew Burgess + + * gdb.linespec/cp-completion-aliases.cc: New file. + * gdb.linespec/cp-completion-aliases.exp: New file. + 2020-03-19 Tom de Vries * gdb.opt/inline-locals.exp: Add kfail PR number. Make kfail matching -- cgit v1.1