Use remote register numbers in tracepoint mask

Use remote register numbers in tracepoint mask

Currently, tracepoint register masks in the QTDP packets include both
internal and remote register numbers, as well as pseudo-register
numbers.

This patch changes this so that the mask only includes remote register
numbers.

Register numbers from agent expressions are already set in the mask
using remote numbers.  Other tracepoint actions used internal numbers,
e.g. "collect $regs" or "collect $<pseudoreg>".  To handle pseudoreg
numbers, an empty agent expression is created and ax_reg_mask is
called for this expression and the pseudoreg.  This will cause the ax
to set its mask with the corresponding remote raw register
numbers (using ax_regs_mask, which calls
gdbarch_ax_pseudo_register_collect).

If ax_regs_mask and gdbarch_ax_pseudo_register_collect also generate
more ax bytecode, the ax is also appended to the collection list.  It
isn't clear that this was the original intent for
gdbarch_ax_pseudo_register_collect, and none of the arches seem to do
this, but if this changes in the future, it should work.

The patch also refactors the code used by validate_action line to
validate axs into a function that is now called from every place that
generates axs.  Previously, some parts of tracepoint.c that generated
axs didn't check if the ax length was greater than MAX_AGENT_EXPR_LEN.

gdb/ChangeLog:
2018-08-06  Pedro Franco de Carvalho  <pedromfc@linux.ibm.com>

	* tracepoint.h (class collection_list) <add_register>: Remove.
	<add_remote_register, add_ax_registers, add_local_register>:
	Declare.
	<add_memrange>: Add scope parameter.
	* tracepoint.c (encode_actions_1): Likewise.
	(collection_list::add_register): Rename to ...
	(collection_list::add_remote_register): ... this.  Update
	comment.
	(collection_list::add_ax_registers, add_local_register): New
	methods.
	(collection_list::add_memrange): Add scope parameter.  Call
	add_local_register instead of add_register.
	(finalize_tracepoint_aexpr): New function.
	(collection_list::collect_symbol): Update calls to add_memrange.
	Call add_local_register instead of add_register.  Call
	add_ax_registers.  Call finalize_tracepoint_aexpr.
	(encode_actions_1): Get remote regnos for $reg action.  Call
	add_remote_register, add_ax_registers, and add_local_register.
	Update call to add_memrange.  Call finalize_tracepoint_aexpr.
	(validate_actionline): Call finalize_tracepoint_aexpr.