Deploy RRGraphBuilder in Regular Routing Resource Graph Building Functions to replace the use of rr_node_indices

[tangxifan]

Description

This PR focuses on updating the vpr/src/route/rr_graph.cpp, where we use the refactored data structure RRGraphBuilder to replace the legacy data structure rr_node_indices.
This PR aims to eliminate the use of rr_node_indices for the regular RRGraph building functions vpr/src/route/rr_graph.cpp and vpr/src/route/rr_graph2.cpp, as one step further in deprecating the legacy data structure.

Checklist:

• Eliminate the use of rr_node_indices for the regular RRGraph building functions
• Eliminate the use of rr_node_indices for the ClockRRGraph building functions This is due to too many code changes. Prefer to leave for the next pull request.

Related Issue

This pull request is a follow-up PR on the routing resource graph refactoring effort #1693

Motivation and Context

After the previous PR #1747 , we start reworking all the source files that use the legacy data structure rr_node_indices in a high priority, in order to deprecate the legacy data structure as soon as possible.
Current statistics on the files that use rr_node_indices (in total there are 242 lines related):

• ./base/vpr_context.h
• ./base/vpr_types.h
• ./device/rr_graph_view.h
• ./device/rr_spatial_lookup.cpp
• ./device/rr_spatial_lookup.h
• ./pack/post_routing_pb_pin_fixup.cpp Covered in another PR Deploy RRGraphBuilder in Client Functions to replace the use of rr_node_indices #1779
• ./place/timing_place_lookup.cpp Covered in another PR Deploy RRGraphBuilder in Client Functions to replace the use of rr_node_indices #1779
• ./route/clock_connection_builders.cpp
• ./route/clock_network_builders.cpp
• ./route/clock_network_builders.h
• ./route/route_common.cpp Covered in another PR Deploy RRGraphBuilder in Client Functions to replace the use of rr_node_indices #1779
• ./route/router_lookahead_map.cpp Covered in another PR Deploy RRGraphBuilder in Client Functions to replace the use of rr_node_indices #1779
• ./route/router_lookahead_map_utils.cpp Covered in another PR Deploy RRGraphBuilder in Client Functions to replace the use of rr_node_indices #1779
• ./route/rr_graph.cpp
• ./route/rr_graph2.cpp
• ./route/rr_graph2.h
• ./route/rr_graph_clock.cpp
• ./route/rr_graph_clock.h
• ./route/rr_graph_reader.cpp
• ./route/rr_graph_util.cpp
• ./route/rr_graph_uxsdcxx_serializer.h
• ./route/rr_graph_writer.cpp

Considering the fact that some internal scratchpad data structures are still using the int rather than RRNodeId, e.g.,

vtr-verilog-to-routing/vpr/src/route/rr_graph2.h

Lines 21 to 23 in 6e442d1

	struct t_opin_connections_scratchpad {
	std::array<std::vector<int>, 8> scratch;
	};

vtr-verilog-to-routing/vpr/src/route/rr_edge.h

Lines 4 to 9 in 6e442d1

	struct t_rr_edge_info {
	t_rr_edge_info(int from, int to, short type) noexcept
	: from_node(from)
	, to_node(to)
	, switch_type(type) {}

I try to avoid massive changes to the codes for now.
So, in this PR, I will try to limit the changes to rr_graph.cpp.

How Has This Been Tested?

Considering this is all about refactoring, this PR does not need to create new tests. Expect all the existing tests to pass.

Types of changes

• Bug fix (change which fixes an issue)
• New feature (change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My change requires a change to the documentation
• I have updated the documentation accordingly
• I have added tests to cover my changes
• All new and existing tests passed

[tangxifan]

@vaughnbetz @hzeller This PR is ready for your review.

[vaughnbetz]

The changes look good. Glad to see this progressing, and I like that some of the RRNodeId casting is gone now. I don't have any suggestions from improvement; merging.