Tom de Vries
8d76ceb7f1
I filed PR29179 about the following FAIL in test-case gdb.ada/O2_float_param.exp with target board cc-with-gdb-index: ... (gdb) break increment^M Function "increment" not defined.^M Make breakpoint pending on future shared library load? (y or [n]) n^M (gdb) FAIL: gdb.ada/O2_float_param.exp: scenario=all: gdb_breakpoint: \ set breakpoint at increment ... The FAIL was a regression since commit2cf349be0e("Do not put linkage names into .gdb_index"). Before that commit we had: ... $ readelf -w foo > READELF $ grep callee.*increment READELF [1568] callee__increment: 5 [global, function] [3115] callee.increment: 5 [global, function] ... but after only: ... $ grep callee.*increment READELF [3115] callee.increment: 5 [global, function] ... The regression was fixed by commit67e83a0dee("Fix regression in c-linkage-name.exp with gdb index"), which got us again: ... $ grep callee.*increment READELF [1568] callee__increment: 5 [global, function] [3115] callee.increment: 5 [global, function] ... The commit however did not claim that particular PR. A subsequent commit, commit5fea979432("Improve Ada support in .gdb_index") did claim to fix it, together with commitdd05fc7071("Change .gdb_index de-duplication implementation"). The commit5fea979432contained the following addition in write_cooked_index: ... + if (entry->per_cu->lang () == language_ada) + { + /* We want to ensure that the Ada main function's name + appears verbatim in the index. However, this name will + be of the form "_ada_mumble", and will be rewritten by + ada_decode. So, recognize it specially here and add it + to the index by hand. */ + if (entry->tag == DW_TAG_subprogram + && strcmp (main_for_ada, name) == 0) + { + /* Leave it alone. */ + } + else + { + /* In order for the index to work when read back into + gdb, it has to use the encoded name, with any + suffixes stripped. */ + std::string encoded = ada_encode (name, false); + name = obstack_strdup (&symtab->m_string_obstack, + encoded.c_str ()); + } + } ... The code contains some special handling related to the Ada main function, so let's look at that one: foo. Before commit67e83a0deewe have: ... $ grep foo.*function READELF [3733] foo: 7 [global, function] ... and after: ... $ grep foo.*function READELF [2738] _ada_foo: 7 [global, function] [3733] foo: 7 [global, function] ... so that looks identical to the callee.increment case. At commit5fea979432, we have slightly different index numbers: ... $ grep foo.*function READELF [1658] foo: 7 [global, function] [2738] _ada_foo: 7 [global, function] ... but otherwise the same result. If we disable the special handling of the Ada main function like so: ... - if (entry->tag == DW_TAG_subprogram + if (false && entry->tag == DW_TAG_subprogram ... we still have the exact same result because: ... (gdb) p main_for_ada $1 = 0x352e6a0 "_ada_foo" ... and ada_encode ("_ada_foo", false) == "_ada_foo". The comment seems to be copied from debug_names::insert, which does indeed use ada_decode, while the code in write_cooked_index uses ada_encode instead. Remove the superfluous special handling of Ada main in write_cooked_index. Tested on x86_64-linux, with target boards unix and cc-with-gdb-index. Approved-By: Tom Tromey <tom@tromey.com>
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