This patch adds support for range stepping to GDBserver, teaching it
about vCont;r.
It'd be easy to enable this for all hardware single-step targets
without needing the linux_target_ops hook, however, at least PPC needs
special care, due to the fact that PPC atomic sequences can't be
hardware single-stepped through, a thing which GDBserver doesn't know
about. So this leaves the support limited to x86/x86_64.
gdb/
2013-05-23 Pedro Alves <palves@redhat.com>
* NEWS: Mention GDBserver range stepping support.
gdb/gdbserver/
2013-05-23 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* linux-low.c (lwp_in_step_range): New function.
(linux_wait_1): If the thread was range stepping and stopped
outside the stepping range, report the stop to GDB. Otherwise,
continue stepping. Add range stepping debug output.
(linux_set_resume_request): Copy the step range from the resume
request to the lwp.
(linux_supports_range_stepping): New.
(linux_target_ops) <supports_range_stepping>: Set to
linux_supports_range_stepping.
* linux-low.h (struct linux_target_ops)
<supports_range_stepping>: New field.
(struct lwp_info) <step_range_start, step_range_end>: New fields.
* linux-x86-low.c (x86_supports_range_stepping): New.
(the_low_target) <supports_range_stepping>: Set to
x86_supports_range_stepping.
* server.c (handle_v_cont): Handle 'r' action.
(handle_v_requests): Append ";r" if the target supports range
stepping.
* target.h (struct thread_resume) <step_range_start,
step_range_end>: New fields.
(struct target_ops) <supports_range_stepping>:
New field.
(target_supports_range_stepping): New macro.
This patch teaches GDB to take advantage of target-assisted range
stepping. It adds a new 'r ADDR1,ADDR2' action to vCont (vCont;r),
meaning, "step once, and keep stepping as long as the thread is in the
[ADDR1,ADDR2) range".
Rationale:
When user issues the "step" command on the following line of source,
a = b + c + d * e - a;
GDB single-steps every single instruction until the program reaches a
new different line. E.g., on x86_64, that line compiles to:
0x08048434 <+65>: mov 0x1c(%esp),%eax
0x08048438 <+69>: mov 0x30(%esp),%edx
0x0804843c <+73>: add %eax,%edx
0x0804843e <+75>: mov 0x18(%esp),%eax
0x08048442 <+79>: imul 0x2c(%esp),%eax
0x08048447 <+84>: add %edx,%eax
0x08048449 <+86>: sub 0x34(%esp),%eax
0x0804844d <+90>: mov %eax,0x34(%esp)
0x08048451 <+94>: mov 0x1c(%esp),%eax
and the following is the RSP traffic between GDB and GDBserver:
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:3c840408;thread:p2e13.2e13;core:1;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:3e840408;thread:p2e13.2e13;core:2;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:42840408;thread:p2e13.2e13;core:2;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:47840408;thread:p2e13.2e13;core:0;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:49840408;thread:p2e13.2e13;core:0;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:4d840408;thread:p2e13.2e13;core:0;
--> vCont;s:p2e13.2e13;c
<-- T0505:68efffbf;04:30efffbf;08:51840408;thread:p2e13.2e13;core:0;
IOW, a lot of roundtrips between GDB and GDBserver.
If we add a new command to the RSP, meaning "keep stepping and don't
report a stop until the program goes out of the [0x08048434,
0x08048451) address range", then the RSP traffic can be reduced down
to:
--> vCont;r8048434,8048451:p2db0.2db0;c
<-- T0505:68efffbf;04:30efffbf;08:51840408;thread:p2db0.2db0;core:1;
As number of packets is reduced dramatically, the performance of
stepping source lines is much improved.
In case something is wrong with range stepping on the stub side, the
debug info or even gdb, this adds a "set/show range-stepping" command
to be able to turn range stepping off.
gdb/
2013-05-23 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* gdbthread.h (struct thread_control_state) <may_range_step>: New
field.
* infcmd.c (step_once, until_next_command): Enable range stepping.
* infrun.c (displaced_step_prepare): Disable range stepping.
(resume): Disable range stepping if stepping over a breakpoint or
we have software watchpoints. If range stepping is enabled,
assert the thread is in the stepping range.
(clear_proceed_status_thread): Clear may_range_step.
(handle_inferior_event): Disable range stepping as soon as we know
the thread that hit the event. Re-enable it whenever we're going
to step with a step range.
* remote.c (struct vCont_action_support) <r>: New field.
(use_range_stepping): New global.
(remote_vcont_probe): Handle 'r' action.
(append_resumption): Append an 'r' action if the thread may range
step.
(show_range_stepping): New function.
(set_range_stepping): New function.
(_initialize_remote): Call add_setshow_boolean_cmd to register the
'set range-stepping' and 'show range-stepping' commands.
* NEWS: Mention range stepping, the new vCont;r action, and the
new "set/show range-stepping" commands.
gdb/doc/
2013-05-23 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* gdb.texinfo (Packets): Document 'vCont;r'.
(Continuing and Stepping): Document target-assisted range
stepping, and the 'set range-stepping' and 'show range-stepping'
commands.
Convert the 'support_vCont_t' int field to a struct, in preparation
for adding more fields to it.
gdb/
2013-05-23 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* remote.c (struct vCont_action_support): New struct.
(struct remote_state) <support_vCont_t>: Remove field.
<vCont_actions_support>: New field.
(remote_vcont_probe, remote_stop_ns): Update.
This adds a function for doing within-thread's-stepping-range checks,
and converts a couple spots to use it. Following patches will add
more uses.
gdb/
2013-05-23 Yao Qi <yao@codesourcery.com>
Pedro Alves <palves@redhat.com>
* gdbthread.h (pc_in_thread_step_range): New declaration.
* thread.c (pc_in_thread_step_range): New function.
* infrun.c (handle_inferior_event): Use it.
'func_name' from find_frame_funname.
(ada_unhandled_exception_name_addr_from_raise): Add cleanups
for func_name from find_frame_funname.
* python/py-frame.c (frapy_name): Add explicit free of
'name' from find_frame_funname.
* stack.c (find_frame_funname): Add comment explaining that
funcp must be freed by the caller.
Return copy of symbol names instead of pointers.
(print_frame): Add a cleanup for 'funname' from
find_frame_funname.
* stack.h (find_frame_funname): Remove "const" from
'funname' parameter.
* c-valprint.c (c_value_print): Use value_addr for
references. Convert back to reference type with value_ref.
gdb/testsuite
* gdb.cp/class2.cc (main): New local 'aref'.
* gdb.cp/class2.exp: Check printing of 'aref'.
* ui-out.c: Create typedef ui_out_level_p and define vector
operations for that type.
(struct ui_out): Use a vector instead of an array.
(current_level): Return level from a vector.
(push_level): Create a level in a vector.
(pop_level): Delete a level in a vector.
(ui_out_new): Create initial level zero level, and store in a
vector.
(ui_out_destroy): Add vector cleanup.
The ARI complains with:
> gdb/python/python-internal.h:177: code: editCase function: Function name starts lower case but has uppercased letters.
gdb/python/python-internal.h:177:gdb_Py_DECREF (void *op)
gdb_Py_DECREF is just wrapping a python macro that happens to be mixed case.
gdb/
2013-05-22 Pedro Alves <palves@redhat.com>
* python/python-internal.h (gdb_Py_DECREF): Tag with
"ARI: editCase function".
The only difference between Py_DECREF and Py_XDECREF is that the latter allows passing
in a NULL object, while the former prohibits it. Given that, it's natural to expect
the same from py_decref vs py_xdecref.
gdb/
2013-05-21 Pedro Alves <palves@redhat.com>
* python/py-prettyprint.c (apply_val_pretty_printer): Check
whether PRINTER is NULL before installing a Py_DECREF cleanup.
* python/py-utils.c (py_decref): Don't check for NULL before
calling Py_DECREF.
Wrap/redefine Py_DECREF ourselves, avoiding the need for uses to care
about extra braces due to the fact that Python only started wrapping Py_DECREF
in 'do {} while (0)' after 2.6.
gdb/
2013-05-21 Pedro Alves <palves@redhat.com>
* python/py-utils.c (py_decref): Remove extra braces.
(gdb_pymodule_addobject): Remove extra braces.
* python-internal.h (gdb_Py_DECREF): New static inline function.
(Py_DECREF): Redefine as calling gdb_Py_DECREF.
Code cleanup: constification.
* solib.c (solib_ops): Make return type and ops variable type const.
(set_solib_ops): Make the new_ops parameter and ops variable const.
(solib_find, solib_map_sections, clear_so, free_so, update_solib_list)
(solib_add, solib_keep_data_in_core, clear_solib)
(solib_create_inferior_hook, in_solib_dynsym_resolve_code)
(reload_shared_libraries, solib_global_lookup): Make the ops variable
const.
* solib.h (set_solib_ops): Make the new_ops parameter const.
gdb/ChangeLog:
* data-directory/Makefile.in (SYSTEM_GDBINIT_SRCDIR): New
variable.
(VPATH): Add SYSTEM_GDBINIT_SRCDIR.
(SYSTEM_GDBINIT_DIR, SYSTEM_GDBINIT_INSTALL_DIR)
(SYSTEM_GDBINIT_FILES): New variables.
(all): Add stamp-system-gdbinit.
(stamp-system-gdbinit): New rule.
(clean-system-gdbinit, install-system-gdbinit)
(uninstall-system-gdbinit): New rules. Make them .PHONY.
(install-only): Add dependency on install-system-gdbinit.
(uninstall): Add dependency on uninstall-system-gdbinit.
(clean): Add dependency on clean-system-gdbinit.
* system-gdbinit/elinos.py: New file.
* system-gdbinit/wrs-linux.py: New file.
get_addr_from_python calls out of TRY_CATCH.
(infpy_write_memory, infpy_search_memory): Likewise.
* python/py-utils.c (get_addr_from_python): Return negative
value on error. Use TRY_CATCH.
* python/python-internal.h (get_addr_from_python): Use
CPYCHECKER_NEGATIVE_RESULT_SETS_EXCEPTION.
CPYCHECKER_RETURNS_BORROWED_REF.
* python/python-internal.h (CPYCHECKER_RETURNS_BORROWED_REF):
New define.
(pspace_to_pspace_object, objfile_to_objfile_object)
(find_thread_object): Use it.
For Fission.
* dwarf2read.c (struct dwarf2_per_cu_data): New member
reading_dwo_directly.
(struct signatured_type): New member dwo_unit.
(struct die_reader_specs): New member comp_dir.
(create_signatured_type_table_from_index): Use malloc for
all_type_units instead of objfile's obstack.
(create_all_type_units): Ditto.
(fill_in_sig_entry_from_dwo_entry): New function.
(add_type_unit): New function.
(lookup_dwo_signatured_type): New function.
(lookup_dwp_signatured_type): New function.
(lookup_signatured_type): New arg cu. All callers updated.
(init_cu_die_reader): Initialize comp_dir.
(read_cutu_die_from_dwo): New arg stub_comp_dir. All callers updated.
Change assert of matching type signatures to call error on mismatch.
(lookup_dwo_unit): Add assert.
(init_tu_and_read_dwo_dies): New function.
(init_cutu_and_read_dies): Call it.
(build_type_unit_groups): Handle case of no type unit groups created.
(hash_dwo_file, eq_dwo_file): Handle missing comp_dir.
(lookup_dwo_cutu): Tweak complaint.
(dwarf2_free_abbrev_table): Check for NULL abbrev_table.
(dwarf2_per_objfile_free): Free all_type_units.
