gas: sparc: fix collision of registers and pseudo-ops.

gas: sparc: fix collision of registers and pseudo-ops.

The current sparc assembler breaks when the name of an ancillary-state
register, privileged register or hyperprivileged register has a
%-pseudo-operation name as a prefix.  For example, %hmcdper and %hm(),
or %hintp and %hi().

This patch fixes it by introducing a new table `perc_table' (for
%-table) that contains an entry for every %name supported by the
assembler, other than the general registers.  This table is used to
detect name collisions when the assembler tries to detect a %-pseudo-op.

This patch also fixes a related bug, making sure that v9a_asr_table and
hpriv_reg_table are sorted in reverse lexicographic order, as otherwise
the search code may fail.

gas/ChangeLog:

2016-06-17  Jose E. Marchesi  <jose.marchesi@oracle.com>

	* config/tc-sparc.c (priv_reg_table): Use NULL instead of the
	empty string to mark the end of the array.
	(hpriv_reg_table): Likewise.
	(v9a_asr_table): Likewise.
	(cmp_reg_entry): Handle entries with NULL names.
	(F_POP_V9): Define.
	(F_POP_PCREL): Likewise.
	(F_POP_TLS_CALL): Likewise.
	(F_POP_POSTFIX): Likewise.
	(struct pop_entry): New type.
	(pop_table): New variable.
	(enum pop_entry_type): New type.
	(struct perc_entry): Likewise.
	(NUM_PERC_ENTRIES): Define.
	(perc_table): New variable.
	(cmp_perc_entry): New function.
	(md_begin): Sort hpriv_reg_table and v9a_asr_table, and initialize
	perc_table.
	(sparc_ip): Handle entries with NULL names in priv_reg_table,
	hpriv_reg_table and v9a_asr_table.  Use perc_table to handle
	%-pseudo-ops.