PR debug/81307
	* dbxout.c (lastlineno): New variable.
	(dbx_debug_hooks): Use dbxout_switch_text_section as
	switch_text_section debug hook.
	(dbxout_function_end): Switch to current_function_section
	rather than function_section.  If crtl->has_bb_partition,
	output just one N_FUN, depending on in_cold_section_p.
	(dbxout_source_line): Remember last lineno in lastlineno.
	(dbxout_switch_text_section): New function.
	(dbxout_function_decl): Adjust dbxout_block caller.
	(dbx_block_with_cold_children): New function.
	(dbxout_block): Return true if any LBRAC/RBRAC have been
	emitted.  Use dbx_block_with_cold_children at depth == 0
	in second partition.  Add PARENT_BLOCKNUM argument, pass
	it optionally adjusted to children.  Output LBRAC/RBRAC
	around recursive call only if the block is in the current
	partition, if not and anything was output, emit empty
	range LBRAC/RBRAC.
	* final.c (final_scan_insn): Compute cold_function_name
	before calling switch_text_section debug hook.  Call
	that hook even if dwarf2out_do_frame if not emitting
	dwarf debug info.

	* g++.dg/debug/debug9.C: Remove -fno-reorder-blocks-and-partition
	workaround.

From-SVN: r255161