Added opt_rmports pass (remove unconnected ports from top-level modules)

2 files changed, 133 insertions, 0 deletions

diff --git a/passes/opt/Makefile.inc b/passes/opt/Makefile.inc
index a8b1537bb..7d54adf0f 100644
--- a/passes/opt/Makefile.inc
+++ b/passes/opt/Makefile.inc
@@ -6,6 +6,7 @@ OBJS += passes/opt/opt_reduce.o
 OBJS += passes/opt/opt_rmdff.o
 OBJS += passes/opt/opt_clean.o
 OBJS += passes/opt/opt_expr.o
+OBJS += passes/opt/opt_rmports.o
 
 ifneq ($(SMALL),1)
 OBJS += passes/opt/share.o
diff --git a/passes/opt/opt_rmports.cc b/passes/opt/opt_rmports.cc
new file mode 100644
index 000000000..2fd73fff2
--- /dev/null
+++ b/passes/opt/opt_rmports.cc
@@ -0,0 +1,132 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted, provided that the above
+ *  copyright notice and this permission notice appear in all copies.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ */
+
+#include "kernel/register.h"
+#include "kernel/sigtools.h"
+#include "kernel/log.h"
+#include <stdlib.h>
+#include <stdio.h>
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+struct OptRmportsPass : public Pass {
+	OptRmportsPass() : Pass("opt_rmports", "remove top-level ports with no connections") { }
+	virtual void help()
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    opt_rmports\n");
+		log("\n");
+		log("This pass identifies ports in the top-level design which are not used or driven\n");
+		log("and removes them\n");
+		log("\n");
+	}
+
+	virtual void execute(std::vector<std::string> /*args*/, RTLIL::Design *design)
+	{
+		log_header(design, "Executing OPT_RMPORTS pass (remove top level ports with no connections).\n");
+
+		//vector<RTLIL::Module*> mods = design->modules();
+		//for(auto mod : mods)
+		//	ProcessModule(mod);
+		ProcessModule(design->top_module());
+	}
+
+	virtual void ProcessModule(RTLIL::Module* module)
+	{
+		log("Finding unconnected ports in module %s\n", module->name.c_str());
+
+		std::set<RTLIL::IdString> used_ports;
+
+		//See what wires are used.
+		//Start by checking connections between named wires
+		auto& conns = module->connections();
+		for(auto sigsig : conns)
+		{
+			auto s1 = sigsig.first.as_wire();
+			auto s2 = sigsig.second.as_wire();
+
+			if( (s1->port_input || s1->port_output) && (used_ports.find(s1->name) == used_ports.end()) )
+				used_ports.emplace(s1->name);
+
+			if( (s2->port_input || s2->port_output) && (used_ports.find(s2->name) == used_ports.end()) )
+				used_ports.emplace(s2->name);
+		}
+
+		//Then check connections to cells
+		auto cells = module->cells();
+		for(auto cell : cells)
+		{
+			auto& cconns = cell->connections();
+			for(auto conn : cconns)
+			{
+				if(!conn.second.is_wire())
+					continue;
+				auto sig = conn.second.as_wire();
+
+				if( (sig->port_input || sig->port_output) && (used_ports.find(sig->name) == used_ports.end()) )
+					used_ports.emplace(sig->name);
+			}
+		}
+
+		//Now that we know what IS used, get rid of anything that isn't in that list
+		std::set<RTLIL::IdString> unused_ports;
+		for(auto port : module->ports)
+		{
+			if(used_ports.find(port) != used_ports.end())
+				continue;
+			unused_ports.emplace(port);
+		}
+
+		//Print the ports out as we go through them
+		for(auto port : unused_ports)
+		{
+			log("  removing unused top-level port %s\n", port.c_str());
+
+			//Remove from ports list
+			for(size_t i=0; i<module->ports.size(); i++)
+			{
+				if(module->ports[i] == port)
+				{
+					module->ports.erase(module->ports.begin() + i);
+					break;
+				}
+			}
+
+			//Mark the wire as no longer a port
+			auto wire = module->wire(port);
+			wire->port_input = false;
+			wire->port_output = false;
+			wire->port_id = 0;
+		}
+		log("Removed %zu unused top-level ports.\n", unused_ports.size());
+
+		//Re-number all of the wires that DO have ports still on them
+		for(size_t i=0; i<module->ports.size(); i++)
+		{
+			auto port = module->ports[i];
+			auto wire = module->wire(port);
+			wire->port_id = i+1;
+		}
+	}
+
+} OptRmportsPass;
+
+PRIVATE_NAMESPACE_END