From: Tom de Vries Date: Fri, 28 Feb 2020 15:14:53 +0000 (+0100) Subject: [gdb] Don't set initial language using previous language X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=658dadf0b02b618fe81e7b09ad930479941f2236;p=binutils-gdb.git [gdb] Don't set initial language using previous language When language is set to auto, part of loading an executable is to update the language accordingly. This is implemented by set_initial_language. In case of a c++ executable without DW_AT_main_subprogram, set_initial_language finds "main" in the minimal symbols, and does a lookup of "main" in the symbol tables to determine the language of the symbol, and uses that as initial language. The symbol lookup is done using lookup_symbol which is a wrapper around lookup_symbol_in_language, using the current language. So, consider two c++ executables a.out and b.out, which we'll load one after another. If we track the resulting lookup_symbol_in_language calls: ... $ gdb -batch \ -ex "b lookup_symbol_in_language" \ -ex r -ex c -ex c \ --args gdb ... we find that indeed lookup_symbol_in_language is called once using language_c, and once using language_c_plus: ... (gdb) file a.out Reading symbols from a.out... Breakpoint 1, lookup_symbol_in_language (name=0x5555568c2050 "main", \ block=0x0, domain=VAR_DOMAIN, lang=language_c, is_a_field_of_this=0x0) \ at ../../gdb/symtab.c:1905 1905 { (gdb) file b.out Load new symbol table from "b.out"? (y or n) y Reading symbols from b.out... Breakpoint 1, lookup_symbol_in_language (name=0x5555568c2030 "main", \ block=0x0, domain=VAR_DOMAIN, lang=language_cplus, is_a_field_of_this=0x0) \ at ../../gdb/symtab.c:1905 1905 { (gdb) ... It seems like a bad idea to have the previous language play a role in determining the executable language. Fix this by using lookup_symbol_in_language in set_initial_language with the default language c as argument. Tested on x86_64-linux. gdb/ChangeLog: 2020-02-28 Tom de Vries * symfile.c (set_initial_language): Use default language for lookup. --- diff --git a/gdb/ChangeLog b/gdb/ChangeLog index fce2a03a5d3..5f49542fb82 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,7 @@ +2020-02-28 Tom de Vries + + * symfile.c (set_initial_language): Use default language for lookup. + 2020-02-28 Simon Marchi * dwarf2/read.c (cutu_reader::init_tu_and_read_dwo_dies): Remove diff --git a/gdb/symfile.c b/gdb/symfile.c index f1edf2dca5d..01c3f5af126 100644 --- a/gdb/symfile.c +++ b/gdb/symfile.c @@ -1684,11 +1684,15 @@ set_initial_language (void) if (language_mode == language_mode_manual) return; enum language lang = main_language (); + /* Make C the default language. */ + enum language default_lang = language_c; if (lang == language_unknown) { const char *name = main_name (); - struct symbol *sym = lookup_symbol (name, NULL, VAR_DOMAIN, NULL).symbol; + struct symbol *sym + = lookup_symbol_in_language (name, NULL, VAR_DOMAIN, default_lang, + NULL).symbol; if (sym != NULL) lang = sym->language (); @@ -1696,8 +1700,7 @@ set_initial_language (void) if (lang == language_unknown) { - /* Make C the default language */ - lang = language_c; + lang = default_lang; } set_language (lang);