Params plugin: Add get_param command

Signed-off-by: Tomasz Michalak <tmichalak@antmicro.com>

params-plugin/Makefile

diff --git a/params-plugin/Makefile b/params-plugin/Makefile
new file mode 100644
index 0000000..d0fd047
--- /dev/null
+++ b/params-plugin/Makefile
@@ -0,0 +1,25 @@
+CXX = $(shell yosys-config --cxx)
+CXXFLAGS = $(shell yosys-config --cxxflags)
+LDFLAGS = $(shell yosys-config --ldflags)
+LDLIBS = $(shell yosys-config --ldlibs)
+PLUGINS_DIR = $(shell yosys-config --datdir)/plugins
+
+OBJS = params.o
+
+params.so: $(OBJS)
+	$(CXX) $(CXXFLAGS) $(LDFLAGS) -shared -o $@ $^ $(LDLIBS)
+
+install_plugin: params.so
+	mkdir -p $(PLUGINS_DIR)
+	cp $< $(PLUGINS_DIR)/$<
+
+test: install_plugin
+	$(MAKE) -C tests all
+
+.PHONY: install
+install: install_plugin
+
+clean:
+	rm -f *.d *.o params.so
+	$(MAKE) -C tests clean
+

params-plugin/params.cc

diff --git a/params-plugin/params.cc b/params-plugin/params.cc
new file mode 100644
index 0000000..19cebfb
--- /dev/null
+++ b/params-plugin/params.cc
@@ -0,0 +1,82 @@
+/*
+ *  yosys -- Yosys Open SYnthesis Suite
+ *
+ *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
+ *  Copyright (C) 2020  The Symbiflow Authors
+ *
+ *  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/rtlil.h"
+#include "kernel/log.h"
+
+USING_YOSYS_NAMESPACE
+
+PRIVATE_NAMESPACE_BEGIN
+
+
+void register_in_tcl_interpreter(const std::string& command) {
+	Tcl_Interp* interp = yosys_get_tcl_interp();
+	std::string tcl_script = stringf("proc %s args { return [yosys %s {*}$args] }", command.c_str(), command.c_str());
+	Tcl_Eval(interp, tcl_script.c_str());
+}
+
+struct GetParam : public Pass {
+	GetParam() : Pass("get_param", "get parameter on object") {
+		register_in_tcl_interpreter(pass_name);
+	}
+
+	void help() override
+	{
+		//   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
+		log("\n");
+		log("   get_param name selection\n");
+		log("\n");
+		log("Get the given parameter on the selected object. \n");
+		log("\n");
+	}
+
+	void execute(std::vector<std::string> args, RTLIL::Design* design) override
+	{
+		if (args.size() == 1) {
+			log_error("Incorrect number of arguments");
+		}
+
+		std::string param(args.at(1));
+		std::string value;
+		extra_args(args, 2, design);
+
+		for (auto module : design->selected_modules()) {
+			for (auto cell : module->selected_cells()) {
+				auto params = cell->parameters;
+				auto it = params.find(RTLIL::IdString(RTLIL::escape_id(param)));
+				if (it != params.end()) {
+					auto param_obj = it->second;
+					if (param_obj.flags & RTLIL::CONST_FLAG_STRING) {
+						value = param_obj.decode_string();
+					} else {
+						value = std::to_string(param_obj.as_int());
+					}
+				}
+			}
+		}
+
+		char* tcl_param = Tcl_Alloc(value.size() + 1);
+		strcpy(tcl_param, value.c_str());
+		Tcl_Interp *interp = yosys_get_tcl_interp();
+		Tcl_SetResult(interp, tcl_param, TCL_DYNAMIC);
+	}
+
+} GetParam;
+
+PRIVATE_NAMESPACE_END