[PATCH 30/40] Use search_domain::FUNCTIONS_DOMAIN when setting breakpoints

Pedro Alves
2017-06-02T12:30:00Z

While working on C++ support for wild matching, I noticed that
attaching to my system's Firefox (which uses .gdb_index), setting a
break at main and bailing, like:

$ gdb --batch -q -p `pidof firefox` -ex "b main"

would get substancially slower. It'd take around 20s when currently
it takes 3s.

The problem is that gdb would expand more symtabs than currently,
because Firefox has symbols named like "nsHtml5Atoms::main",
"nsGkAtoms::main", etc., which given wild matching, match.

However, these are not function symbols, [they're "(nsIAtom *)"], so
it seems silly that they'd cause expansion in the first place.

The .gdb_index code (dwarf2read.c:dw2_expand_marked_cus) filters out
symbols matches based on search_domain:

case VARIABLES_DOMAIN:
if (symbol_kind != GDB_INDEX_SYMBOL_KIND_VARIABLE)
continue;
break;
case FUNCTIONS_DOMAIN:
if (symbol_kind != GDB_INDEX_SYMBOL_KIND_FUNCTION)
continue;
break;
case TYPES_DOMAIN:
if (symbol_kind != GDB_INDEX_SYMBOL_KIND_TYPE)
continue;
break;
default:
break;

however, we're currently passing down search_domain::ALL_DOMAIN when
we know we're looking for functions, for no good reason. This patch
fixes that.

It seems like search_domain is underutilized throughout, but I'll
leave using it more for another pass.

gdb/ChangeLog:
yyyy-mm-dd Pedro Alves <palves@redhat.com>

* linespec.c (iterate_over_all_matching_symtabs): Add
search_domain parameter. Pass it down to expand_symtabs_matching.
(decode_objc): Request FUNCTIONS_DOMAIN symbols only.
(lookup_prefix_sym): Adjust by passing ALL_DOMAIN as
search_domain.
(add_all_symbol_names_from_pspace): Add search_domain parameter.
Pass it down.
(find_method, find_function_symbols): Request FUNCTIONS_DOMAIN
symbols.
(add_matching_symbols_to_info): Add search_domain parameter. Pass
it down.
---
gdb/linespec.c | 32 ++++++++++++++++++++------------
1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/gdb/linespec.c b/gdb/linespec.c
index fa07534..5d95308 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -363,12 +363,14 @@ static int symbol_to_sal (struct symtab_and_line *result,

static void add_matching_symbols_to_info (const char *name,
symbol_name_match_type name_match_type,
+ enum search_domain search_domain,
struct collect_info *info,
struct program_space *pspace);

static void add_all_symbol_names_from_pspace (struct collect_info *info,
struct program_space *pspace,
- VEC (const_char_ptr) *names);
+ VEC (const_char_ptr) *names,
+ enum search_domain search_domain);

static VEC (symtab_ptr) *
collect_symtabs_from_filename (const char *file,
@@ -1107,6 +1109,7 @@ iterate_over_all_matching_symtabs
(struct linespec_state *state,
const lookup_name_info &lookup_name,
const domain_enum name_domain,
+ enum search_domain search_domain,
struct program_space *search_pspace, bool include_inline,
gdb::function_view<symbol_found_callback_ftype> callback)
{
@@ -1131,7 +1134,7 @@ iterate_over_all_matching_symtabs
NULL,
lookup_name,
NULL, NULL,
- ALL_DOMAIN);
+ search_domain);

ALL_OBJFILE_COMPUNITS (objfile, cu)
{
@@ -3461,7 +3464,8 @@ decode_objc (struct linespec_state *self, linespec_p ls, const char *arg)
return values;
}

- add_all_symbol_names_from_pspace (&info, NULL, symbol_names);
+ add_all_symbol_names_from_pspace (&info, NULL, symbol_names,
+ FUNCTIONS_DOMAIN);

if (!VEC_empty (symbolp, info.result.symbols)
|| !VEC_empty (bound_minimal_symbol_d, info.result.minimal_symbols))
@@ -3588,11 +3592,11 @@ lookup_prefix_sym (struct linespec_state *state, VEC (symtab_ptr) *file_symtabs,
if (elt == NULL)
{
iterate_over_all_matching_symtabs (state, lookup_name,
- STRUCT_DOMAIN, NULL, false,
- collector);
+ STRUCT_DOMAIN, ALL_DOMAIN,
+ NULL, false, collector);
iterate_over_all_matching_symtabs (state, lookup_name,
- VAR_DOMAIN, NULL, false,
- collector);
+ VAR_DOMAIN, ALL_DOMAIN,
+ NULL, false, collector);
}
else
{
@@ -3676,7 +3680,8 @@ compare_msymbols (const void *a, const void *b)
static void
add_all_symbol_names_from_pspace (struct collect_info *info,
struct program_space *pspace,
- VEC (const_char_ptr) *names)
+ VEC (const_char_ptr) *names,
+ enum search_domain search_domain)
{
int ix;
const char *iter;
@@ -3684,7 +3689,7 @@ add_all_symbol_names_from_pspace (struct collect_info *info,
for (ix = 0; VEC_iterate (const_char_ptr, names, ix, iter); ++ix)
add_matching_symbols_to_info (iter,
symbol_name_match_type::FULL,
- info, pspace);
+ search_domain, info, pspace);
}

static void
@@ -3791,7 +3796,8 @@ find_method (struct linespec_state *self, VEC (symtab_ptr) *file_symtabs,
/* We have a list of candidate symbol names, so now we
iterate over the symbol tables looking for all
matches in this pspace. */
- add_all_symbol_names_from_pspace (&info, pspace, result_names);
+ add_all_symbol_names_from_pspace (&info, pspace, result_names,
+ FUNCTIONS_DOMAIN);

VEC_truncate (typep, superclass_vec, 0);
last_result_len = VEC_length (const_char_ptr, result_names);
@@ -3951,9 +3957,10 @@ find_function_symbols (struct linespec_state *state,
find_imps (name, &symbol_names);
if (!VEC_empty (const_char_ptr, symbol_names))
add_all_symbol_names_from_pspace (&info, state->search_pspace,
- symbol_names);
+ symbol_names, FUNCTIONS_DOMAIN);
else
add_matching_symbols_to_info (name, symbol_name_match_type::WILD,
+ FUNCTIONS_DOMAIN,
&info, state->search_pspace);

do_cleanups (cleanup);
@@ -4550,6 +4557,7 @@ search_minsyms_for_name (struct collect_info *info,
static void
add_matching_symbols_to_info (const char *name,
symbol_name_match_type name_match_type,
+ enum search_domain search_domain,
struct collect_info *info,
struct program_space *pspace)
{
@@ -4563,7 +4571,7 @@ add_matching_symbols_to_info (const char *name,
if (elt == NULL)
{
iterate_over_all_matching_symtabs (info->state, lookup_name,
- VAR_DOMAIN,
+ VAR_DOMAIN, search_domain,
pspace, true, [&] (symbol *sym)
{ return info->add_symbol (sym); });
search_minsyms_for_name (info, lookup_name, pspace, NULL);
--
2.5.5