diagnostics: revamp of dumping of "diagnostics" internal state

diagnostics: revamp of dumping of "diagnostics" internal state

The diagnostics subsystem has a handy dump feature, usable
during debugging via

  (gdb) call global_dc->dump ()

which prints copious amounts of information about the state
of the diagnostics subsystem to stderr.

This patch consolidates the implementation and extends it, adding
various per-sink data (generation options specific to each of text,
SARIF, and HTML).

No functional difference intended outside of the debugger.

gcc/ChangeLog:
	* Makefile.in (OBJS-libcommon): Add diagnostics/dumping.o.
	* diagnostics/buffering.cc: Include "diagnostics/dumping.h".
	(buffer::dump): Reimplement using diagnostics::dumping.
	* diagnostics/context.cc: Include "diagnostics/dumping.h".
	(context::dump): Reimplement using diagnostics::dumping.
	Use sink::dump_kind when listing the sinks.
	(sink::dump): Reimplement using diagnostics::dumping.
	(counters::dump): Likewise.
	* diagnostics/dumping.cc: New file.
	* diagnostics/dumping.h: New file.
	* diagnostics/file-cache.cc: Include "diagnostics/dumping.h".
	(file_cache::dump): Reimplement using diagnostics::dumping.
	(file_cache_slot::dump): Likewise.
	* diagnostics/html-sink.cc: Include "diagnostics/dumping.h".
	(html_generation_options::dump): New.
	(html_sink_buffer::dump): Reimplement using diagnostics::dumping.
	(html_builder::dump): New.
	(html_sink::dump): Reimplement using diagnostics::dumping.
	Add dump of the html_builder.
	(html_file_sink::dump): Replace with...
	(html_file_sink::dump_kind): ...this.
	(html_buffered_sink::dump_kind): New.
	* diagnostics/html-sink.h (html_generation_options::dump): New
	decl.
	* diagnostics/sarif-sink.cc: Include "diagnostics/dumping.h".
	(sarif_serialization_format_json::dump): New.
	(sarif_builder::dump): New.
	(sarif_sink_buffer::dump): Reimplement using diagnostics::dumping.
	(sarif_sink::dump): Likewise.  Add dump of the sarif_builder.
	(sarif_stream_sink::dump_kind): New.
	(sarif_file_sink::dump): Replace with...
	(sarif_file_sink::dump_kind): ...this.
	(get_dump_string_for_sarif_version): New.
	(sarif_generation_options::dump): New.
	(class buffered_sink): Rename to...
	(class sarif_buffered_sink): ...this.
	(sarif_buffered_sink::dump_kind): New.
	* diagnostics/sarif-sink.h (sarif_serialization_format::dump):
	New.
	(sarif_serialization_format_json::dump): New decl.
	(sarif_generation_options::dump): New decl.
	* diagnostics/sink.h (sink::dump_kind): New.
	* diagnostics/text-sink.cc: Include "diagnostics/dumping.h".
	(text_sink_buffer::dump): Reimplement using diagnostics::dumping.
	(text_sink::dump): Likewise.  Emit fields m_show_nesting,
	m_show_locations_in_nesting, and m_show_nesting_levels.
	* diagnostics/text-sink.h (text_sink::dump_kind): New.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>