Convert generic probe interface to C++ (and perform some cleanups)

Convert generic probe interface to C++ (and perform some cleanups)

This patch converts the generic probe interface (gdb/probe.[ch]) to
C++, and also performs some cleanups that were on my TODO list for a
while.

The main changes were the conversion of 'struct probe' to 'class
probe', and 'struct probe_ops' to 'class static_probe_ops'.  The
former now contains all the "dynamic", generic methods that act on a
probe + the generic data related to it; the latter encapsulates a
bunch of "static" methods that relate to the probe type, but not to a
specific probe itself.

I've had to do a few renamings (e.g., on 'struct bound_probe' the
field is called 'probe *prob' now, instead of 'struct probe *probe')
because GCC was complaining about naming the field using the same name
as the class.  Nothing major, though.  Generally speaking, the logic
behind and the design behind the code are the same.

Even though I'm sending a series of patches, they need to be tested
and committed as a single unit, because of inter-dependencies.  But it
should be easier to review in separate logical units.

I've regtested this patch on BuildBot, no regressions found.

gdb/ChangeLog:
2017-11-22  Sergio Durigan Junior  <sergiodj@redhat.com>

	* break-catch-throw.c (fetch_probe_arguments): Use
	'probe.prob' instead of 'probe.probe'.
	* breakpoint.c (create_longjmp_master_breakpoint): Call
	'can_evaluate_arguments' and 'get_relocated_address' methods
	from probe.
	(create_exception_master_breakpoint): Likewise.
	(add_location_to_breakpoint): Use 'sal->prob' instead of
	'sal->probe'.
	(bkpt_probe_insert_location): Call 'set_semaphore' method from
	probe.
	(bkpt_probe_remove_location): Likewise, for 'clear_semaphore'.
	* elfread.c (elf_get_probes): Use 'static_probe_ops' instead
	of 'probe_ops'.
	(probe_key_free): Call 'delete' on probe.
	(check_exception_resume): Use 'probe.prob' instead of
	'probe.probe'.
	* location.c (string_to_event_location_basic): Call
	'probe_linespec_to_static_ops'.
	* probe.c (class any_static_probe_ops): New class.
	(any_static_probe_ops any_static_probe_ops): New variable.
	(parse_probes_in_pspace): Receive 'static_probe_ops' as
	argument.  Adjust code to reflect change.
	(parse_probes): Use 'static_probe_ops' instead of
	'probe_ops'.  Adjust code to reflect change.
	(find_probes_in_objfile): Call methods to get name and
	provider from probe.
	(find_probe_by_pc): Use 'result.prob' instead of
	'result.probe'.  Call 'get_relocated_address' method from
	probe.
	(collect_probes): Adjust comment and argument list to receive
	'static_probe_ops' instead of 'probe_ops'.  Adjust code to
	reflect change.  Call necessary methods from probe.
	(compare_probes): Call methods to get name and provider from
	probes.
	(gen_ui_out_table_header_info): Receive 'static_probe_ops'
	instead of 'probe_ops'.  Use 'std::vector' instead of VEC,
	adjust code accordingly.
	(print_ui_out_not_applicables): Likewise.
	(info_probes_for_ops): Rename to...
	(info_probes_for_spops): ...this.  Receive 'static_probe_ops'
	as argument instead of 'probe_ops'.  Adjust code.  Call
	necessary methods from probe.
	(info_probes_command): Use 'info_probes_for_spops'.
	(enable_probes_command): Pass correct argument to
	'collect_probes'.  Call methods from probe.
	(disable_probes_command): Likewise.
	(get_probe_address): Move to 'any_static_probe_ops::get_address'.
	(get_probe_argument_count): Move to
	'any_static_probe_ops::get_argument_count'.
	(can_evaluate_probe_arguments): Move to
	'any_static_probe_ops::can_evaluate_arguments'.
	(evaluate_probe_argument): Move to
	'any_static_probe_ops::evaluate_argument'.
	(probe_safe_evaluate_at_pc): Use 'probe.prob' instead of
	'probe.probe'.
	(probe_linespec_to_ops): Rename to...
	(probe_linespec_to_static_ops): ...this.  Adjust code.
	(probe_any_is_linespec): Rename to...
	(any_static_probe_ops::is_linespec): ...this.
	(probe_any_get_probes): Rename to...
	(any_static_probe_ops::get_probes): ...this.
	(any_static_probe_ops::type_name): New method.
	(any_static_probe_ops::gen_info_probes_table_header): New
	method.
	(compute_probe_arg): Use 'pc_probe.prob' instead of
	'pc_probe.probe'.  Call methods from probe.
	(compile_probe_arg): Likewise.
	(std::vector<const probe_ops *> all_probe_ops): Delete.
	(std::vector<const static_probe_ops *> all_static_probe_ops):
	New variable.
	(_initialize_probe): Use 'all_static_probe_ops' instead of
	'all_probe_ops'.
	* probe.h (struct info_probe_column) <field_name>: Delete
	extraneous newline
	(info_probe_column_s): Delete type and VEC.
	(struct probe_ops): Delete.  Replace with...
	(class static_probe_ops): ...this and...
	(clas probe): ...this.
	(struct bound_probe) <bound_probe>: Delete extraneous
	newline.  Adjust constructor to receive 'probe' instead of
	'struct probe'.
	<probe>: Rename to...
	<prob>: ...this.  Delete extraneous newline.
	<objfile>: Delete extraneous newline.
	(register_probe_ops): Delete unused prototype.
	(info_probes_for_ops): Rename to...
	(info_probes_for_spops): ...this.  Adjust comment.
	(get_probe_address): Move to 'probe::get_address'.
	(get_probe_argument_count): Move to
	'probe::get_argument_count'.
	(can_evaluate_probe_arguments): Move to
	'probe::can_evaluate_arguments'.
	(evaluate_probe_argument): Move to 'probe::evaluate_argument'.
	* solib-svr4.c (struct svr4_info): Adjust comment.
	(struct probe_and_action) <probe>: Rename to...
	<prob>: ...this.
	(register_solib_event_probe): Receive 'probe' instead of
	'struct probe' as argument.  Use 'prob' instead of 'probe'
	when applicable.
	(solib_event_probe_action): Call 'get_argument_count' method
	from probe.  Adjust comment.
	(svr4_handle_solib_event): Adjust comment.  Call
	'evaluate_argument' method from probe.
	(svr4_create_probe_breakpoints): Call 'get_relocated_address'
	from probe.
	(svr4_create_solib_event_breakpoints): Use 'probe' instead of
	'struct probe'.  Call 'can_evaluate_arguments' from probe.
	* symfile.h: Forward declare 'class probe' instead of 'struct
	probe'.
	* symtab.h: Likewise.
	(struct symtab_and_line) <probe>: Rename to...
	<prob>: ...this.
	* tracepoint.c (start_tracing): Use 'prob' when applicable.
	Call probe methods.
	(stop_tracing): Likewise.