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| author | Tom Tromey <tom@tromey.com> | 2023-10-21 16:38:44 -0600 |
|---|---|---|
| committer | Tom Tromey <tom@tromey.com> | 2024-01-08 18:40:22 -0700 |
| commit | 667ed4b14ddaa9af196481f1757c0e517e80b6ed (patch) | |
| tree | 8717a3e4b2380ce83e1f8532a3ce0b1811a10560 | |
| parent | 309d28d1e49d610f925b286c119be6e2ed2ca81b (diff) | |
| download | gdb-667ed4b14ddaa9af196481f1757c0e517e80b6ed.zip gdb-667ed4b14ddaa9af196481f1757c0e517e80b6ed.tar.gz gdb-667ed4b14ddaa9af196481f1757c0e517e80b6ed.tar.bz2 | |
Avoid language-based lookups in startup path
The previous patches are nearly enough to enable background DWARF
reading. However, this hack in language_defn::get_symbol_name_matcher
causes an early computation of current_language:
/* If currently in Ada mode, and the lookup name is wrapped in
'<...>', hijack all symbol name comparisons using the Ada
matcher, which handles the verbatim matching. */
if (current_language->la_language == language_ada
&& lookup_name.ada ().verbatim_p ())
return current_language->get_symbol_name_matcher_inner (lookup_name);
I considered various options here -- reversing the order of the
checks, or promoting the verbatim mode to not be a purely Ada feature
-- but in the end found that the few calls to this during startup
could be handled more directly.
In the JIT code, and in create_exception_master_breakpoint_hook, gdb
is really looking for a certain kind of symbol (text or data) using a
linkage name. Changing the lookup here is clearer and probably more
efficient as well.
In create_std_terminate_master_breakpoint, the lookup can't really be
done by linkage name (it would require relying on a certain mangling
scheme, and also may trip over versioned symbols) -- but we know that
this spot is C++-specific, and so the language ought to be temporarily
set to C++ here.
After this patch, the "file" case is much faster:
(gdb) file /tmp/gdb
2023-10-23 13:16:54.456 - command started
Reading symbols from /tmp/gdb...
2023-10-23 13:16:54.520 - command finished
Command execution time: 0.225906 (cpu), 0.064313 (wall)
| -rw-r--r-- | gdb/breakpoint.c | 4 | ||||
| -rw-r--r-- | gdb/jit.c | 4 |
2 files changed, 5 insertions, 3 deletions
diff --git a/gdb/breakpoint.c b/gdb/breakpoint.c index bd7f746..ca0bd31 100644 --- a/gdb/breakpoint.c +++ b/gdb/breakpoint.c @@ -3733,6 +3733,8 @@ create_std_terminate_master_breakpoint (void) const char *const func_name = "std::terminate()"; scoped_restore_current_program_space restore_pspace; + scoped_restore_current_language save_language; + set_language (language_cplus); for (struct program_space *pspace : program_spaces) { @@ -3845,7 +3847,7 @@ create_exception_master_breakpoint_hook (objfile *objfile) { struct bound_minimal_symbol debug_hook; - debug_hook = lookup_minimal_symbol (func_name, NULL, objfile); + debug_hook = lookup_minimal_symbol_text (func_name, objfile); if (debug_hook.minsym == NULL) { bp_objfile_data->exception_msym.minsym = &msym_not_found; @@ -880,7 +880,7 @@ jit_breakpoint_re_set_internal (struct gdbarch *gdbarch, program_space *pspace) /* Lookup the registration symbol. If it is missing, then we assume we are not attached to a JIT. */ bound_minimal_symbol reg_symbol - = lookup_minimal_symbol (jit_break_name, nullptr, the_objfile); + = lookup_minimal_symbol_text (jit_break_name, the_objfile); if (reg_symbol.minsym == NULL || reg_symbol.value_address () == 0) { @@ -890,7 +890,7 @@ jit_breakpoint_re_set_internal (struct gdbarch *gdbarch, program_space *pspace) } bound_minimal_symbol desc_symbol - = lookup_minimal_symbol (jit_descriptor_name, NULL, the_objfile); + = lookup_minimal_symbol_linkage (jit_descriptor_name, the_objfile); if (desc_symbol.minsym == NULL || desc_symbol.value_address () == 0) { |