Add "opt_mem" pass

Signed-off-by: Clifford Wolf <clifford@clifford.at>

passes/memory/memory.cc

@@ -35,6 +35,7 @@ struct MemoryPass : public Pass {
 		log("\n");
 		log("This pass calls all the other memory_* passes in a useful order:\n");
 		log("\n");
+		log("    opt_mem\n");
 		log("    memory_dff [-nordff]                (-memx implies -nordff)\n");
 		log("    opt_clean\n");
 		log("    memory_share\n");
@@ -81,6 +82,7 @@ struct MemoryPass : public Pass {
 		}
 		extra_args(args, argidx, design);
 
+		Pass::call(design, "opt_mem");
 		Pass::call(design, flag_nordff ? "memory_dff -nordff" : "memory_dff");
 		Pass::call(design, "opt_clean");
 		Pass::call(design, "memory_share");

passes/opt/Makefile.inc

@@ -1,6 +1,7 @@
 
 OBJS += passes/opt/opt.o
 OBJS += passes/opt/opt_merge.o
+OBJS += passes/opt/opt_mem.o
 OBJS += passes/opt/opt_muxtree.o
 OBJS += passes/opt/opt_reduce.o
 OBJS += passes/opt/opt_rmdff.o

passes/opt/opt_mem.cc

@@ -0,0 +1,143 @@
+/*
+ *  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/yosys.h"
+#include "kernel/sigtools.h"
+
+USING_YOSYS_NAMESPACE
+PRIVATE_NAMESPACE_BEGIN
+
+struct OptMemWorker
+{
+	RTLIL::Design *design;
+	RTLIL::Module *module;
+	SigMap sigmap;
+	bool restart;
+
+	dict<IdString, vector<IdString>> memrd, memwr, meminit;
+	pool<IdString> remove_mem, remove_cells;
+
+	OptMemWorker(RTLIL::Module *module) : design(module->design), module(module), sigmap(module), restart(false)
+	{
+		for (auto &it : module->memories)
+		{
+			memrd[it.first];
+			memwr[it.first];
+			meminit[it.first];
+		}
+
+		for (auto cell : module->cells())
+		{
+			if (cell->type == ID($memrd)) {
+				IdString id = cell->getParam(ID(MEMID)).decode_string();
+				memrd.at(id).push_back(cell->name);
+			}
+
+			if (cell->type == ID($memwr)) {
+				IdString id = cell->getParam(ID(MEMID)).decode_string();
+				memwr.at(id).push_back(cell->name);
+			}
+
+			if (cell->type == ID($meminit)) {
+				IdString id = cell->getParam(ID(MEMID)).decode_string();
+				meminit.at(id).push_back(cell->name);
+			}
+		}
+	}
+
+	~OptMemWorker()
+	{
+		for (auto it : remove_mem)
+		{
+			for (auto cell_name : memrd[it])
+				module->remove(module->cell(cell_name));
+			for (auto cell_name : memwr[it])
+				module->remove(module->cell(cell_name));
+			for (auto cell_name : meminit[it])
+				module->remove(module->cell(cell_name));
+
+			delete module->memories.at(it);
+			module->memories.erase(it);
+		}
+
+		for (auto cell_name : remove_cells)
+			module->remove(module->cell(cell_name));
+	}
+
+	int run(RTLIL::Memory *mem)
+	{
+		if (restart || remove_mem.count(mem->name))
+			return 0;
+
+		if (memwr.at(mem->name).empty() && meminit.at(mem->name).empty()) {
+			log("Removing memory %s.%s with no write ports or init data.\n", log_id(module), log_id(mem));
+			remove_mem.insert(mem->name);
+			return 1;
+		}
+
+		return 0;
+	}
+};
+
+struct OptMemPass : public Pass {
+	OptMemPass() : Pass("opt_mem", "optimize memories") { }
+	void help() YS_OVERRIDE
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("    opt_mem [options] [selection]\n");
+		log("\n");
+		log("This pass performs various optimizations on memories in the design.\n");
+		log("\n");
+	}
+	void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
+	{
+		log_header(design, "Executing OPT_MEM pass (optimize memories).\n");
+
+		size_t argidx;
+		for (argidx = 1; argidx < args.size(); argidx++) {
+			// if (args[argidx] == "-nomux") {
+			// 	mode_nomux = true;
+			// 	continue;
+			// }
+			break;
+		}
+		extra_args(args, argidx, design);
+
+		int total_count = 0;
+		for (auto module : design->selected_modules()) {
+			while (1) {
+				int cnt = 0;
+				OptMemWorker worker(module);
+				for (auto &it : module->memories)
+					if (module->selected(it.second))
+						cnt += worker.run(it.second);
+				if (!cnt && !worker.restart)
+					break;
+				total_count += cnt;
+			}
+		}
+
+		if (total_count)
+			design->scratchpad_set_bool("opt.did_something", true);
+		log("Performed a total of %d transformations.\n", total_count);
+	}
+} OptMemPass;
+
+PRIVATE_NAMESPACE_END