frontends/verilog/preproc.cc - third_party/yosys - Git at Google

 /*
  *  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.
  *
  *  ---
  *
  *  The Verilog frontend.
  *
  *  This frontend is using the AST frontend library (see frontends/ast/).
  *  Thus this frontend does not generate RTLIL code directly but creates an
  *  AST directly from the Verilog parse tree and then passes this AST to
  *  the AST frontend library.
  *
  *  ---
  *
  *  Ad-hoc implementation of a Verilog preprocessor. The directives `define,
  *  `include, `ifdef, `ifndef, `else and `endif are handled here. All other
  *  directives are handled by the lexer (see lexer.l).
  *
  */

 #include "verilog_frontend.h"
 #include "kernel/log.h"
 #include <stdarg.h>
 #include <stdio.h>
 #include <string.h>

 YOSYS_NAMESPACE_BEGIN
 using namespace VERILOG_FRONTEND;

 static std::list<std::string> output_code;
 static std::list<std::string> input_buffer;
 static size_t input_buffer_charp;

 static void return_char(char ch)
 {
 	if (input_buffer_charp == 0)
 		input_buffer.push_front(std::string() + ch);
 	else
 		input_buffer.front()[--input_buffer_charp] = ch;
 }

 static void insert_input(std::string str)
 {
 	if (input_buffer_charp != 0) {
 		input_buffer.front() = input_buffer.front().substr(input_buffer_charp);
 		input_buffer_charp = 0;
 	}
 	input_buffer.push_front(str);
 }

 static char next_char()
 {
 	if (input_buffer.empty())
 		return 0;

 	log_assert(input_buffer_charp <= input_buffer.front().size());
 	if (input_buffer_charp == input_buffer.front().size()) {
 		input_buffer_charp = 0;
 		input_buffer.pop_front();
 		return next_char();
 	}

 	char ch = input_buffer.front()[input_buffer_charp++];
 	return ch == '\r' ? next_char() : ch;
 }

 static std::string skip_spaces()
 {
 	std::string spaces;
 	while (1) {
 		char ch = next_char();
 		if (ch == 0)
 			break;
 		if (ch != ' ' && ch != '\t') {
 			return_char(ch);
 			break;
 		}
 		spaces += ch;
 	}
 	return spaces;
 }

 static std::string next_token(bool pass_newline = false)
 {
 	std::string token;

 	char ch = next_char();
 	if (ch == 0)
 		return token;

 	token += ch;
 	if (ch == '\n') {
 		if (pass_newline) {
 			output_code.push_back(token);
 			return "";
 		}
 		return token;
 	}

 	if (ch == ' ' || ch == '\t')
 	{
 		while ((ch = next_char()) != 0) {
 			if (ch != ' ' && ch != '\t') {
 				return_char(ch);
 				break;
 			}
 			token += ch;
 		}
 	}
 	else if (ch == '"')
 	{
 		while ((ch = next_char()) != 0) {
 			token += ch;
 			if (ch == '"')
 				break;
 			if (ch == '\\') {
 				if ((ch = next_char()) != 0)
 					token += ch;
 			}
 		}
 		if (token == "\"\"" && (ch = next_char()) != 0) {
 			if (ch == '"')
 				token += ch;
 			else
 				return_char(ch);
 		}
 	}
 	else if (ch == '/')
 	{
 		if ((ch = next_char()) != 0) {
 			if (ch == '/') {
 				token += '*';
 				char last_ch = 0;
 				while ((ch = next_char()) != 0) {
 					if (ch == '\n') {
 						return_char(ch);
 						break;
 					}
 					if (last_ch != '*' || ch != '/') {
 						token += ch;
 						last_ch = ch;
 					}
 				}
 				token += " */";
 			}
 			else if (ch == '*') {
 				token += '*';
 				int newline_count = 0;
 				char last_ch = 0;
 				while ((ch = next_char()) != 0) {
 					if (ch == '\n') {
 						newline_count++;
 						token += ' ';
 					} else
 						token += ch;
 					if (last_ch == '*' && ch == '/')
 						break;
 					last_ch = ch;
 				}
 				while (newline_count-- > 0)
 					return_char('\n');
 			}
 			else
 				return_char(ch);
 		}
 	}
 	else
 	{
 		const char *ok = "abcdefghijklmnopqrstuvwxyz_ABCDEFGHIJKLMNOPQRSTUVWXYZ$0123456789";
 		if (ch == '`' || strchr(ok, ch) != NULL)
 		{
 			char first = ch;
 			ch = next_char();
 			if (first == '`' && (ch == '"' || ch == '`')) {
 				token += ch;
 			} else do {
 					if (strchr(ok, ch) == NULL) {
 						return_char(ch);
 						break;
 					}
 					token += ch;
 				} while ((ch = next_char()) != 0);
 		}
 	}
 	return token;
 }

 static void input_file(std::istream &f, std::string filename)
 {
 	char buffer[513];
 	int rc;

 	insert_input("");
 	auto it = input_buffer.begin();

 	input_buffer.insert(it, "`file_push \"" + filename + "\"\n");
 	while ((rc = readsome(f, buffer, sizeof(buffer)-1)) > 0) {
 		buffer[rc] = 0;
 		input_buffer.insert(it, buffer);
 	}
 	input_buffer.insert(it, "\n`file_pop\n");
 }


 static bool try_expand_macro(std::set<std::string> &defines_with_args,
 			     std::map<std::string, std::string> &defines_map,
 			     std::string &tok
 				    )
 {
 	if (tok == "`\"") {
 		std::string literal("\"");
 		// Expand string literal
 		while (!input_buffer.empty()) {
 			std::string ntok = next_token();
 			if (ntok == "`\"") {
 				insert_input(literal+"\"");
 				return true;
 			} else if (!try_expand_macro(defines_with_args, defines_map, ntok)) {
 					literal += ntok;
 			}
 		}
 		return false; // error - unmatched `"
 	} else if (tok.size() > 1 && tok[0] == '`' && defines_map.count(tok.substr(1)) > 0) {
 			std::string name = tok.substr(1);
 			// printf("expand: >>%s<< -> >>%s<<\n", name.c_str(), defines_map[name].c_str());
 			std::string skipped_spaces = skip_spaces();
 			tok = next_token(false);
 			if (tok == "(" && defines_with_args.count(name) > 0) {
 				int level = 1;
 				std::vector<std::string> args;
 				args.push_back(std::string());
 				while (1)
 				{
 					skip_spaces();
 					tok = next_token(true);
 					if (tok == ")" || tok == "}" || tok == "]")
 						level--;
 					if (level == 0)
 						break;
 					if (level == 1 && tok == ",")
 						args.push_back(std::string());
 					else
 						args.back() += tok;
 					if (tok == "(" || tok == "{" || tok == "[")
 						level++;
 				}
 				for (int i = 0; i < GetSize(args); i++)
 					defines_map[stringf("macro_%s_arg%d", name.c_str(), i+1)] = args[i];
 			} else {
 				insert_input(tok);
 				insert_input(skipped_spaces);
 			}
 			insert_input(defines_map[name]);
 			return true;
 	} else if (tok == "``") {
 		// Swallow `` in macro expansion
 		return true;
 	} else return false;
 }

 std::string frontend_verilog_preproc(std::istream &f, std::string filename, const std::map<std::string, std::string> &pre_defines_map,
 		dict<std::string, std::pair<std::string, bool>> &global_defines_cache, const std::list<std::string> &include_dirs)
 {
 	std::set<std::string> defines_with_args;
 	std::map<std::string, std::string> defines_map(pre_defines_map);
 	std::vector<std::string> filename_stack;
 	int ifdef_fail_level = 0;
 	bool in_elseif = false;

 	output_code.clear();
 	input_buffer.clear();
 	input_buffer_charp = 0;

 	input_file(f, filename);

 	defines_map["YOSYS"] = "1";
 	defines_map[formal_mode ? "FORMAL" : "SYNTHESIS"] = "1";

 	for (auto &it : pre_defines_map)
 		defines_map[it.first] = it.second;

 	for (auto &it : global_defines_cache) {
 		if (it.second.second)
 			defines_with_args.insert(it.first);
 		defines_map[it.first] = it.second.first;
 	}

 	while (!input_buffer.empty())
 	{
 		std::string tok = next_token();
 		// printf("token: >>%s<<\n", tok != "\n" ? tok.c_str() : "NEWLINE");

 		if (tok == "`endif") {
 			if (ifdef_fail_level > 0)
 				ifdef_fail_level--;
 			if (ifdef_fail_level == 0)
 				in_elseif = false;
 			continue;
 		}

 		if (tok == "`else") {
 			if (ifdef_fail_level == 0)
 				ifdef_fail_level = 1;
 			else if (ifdef_fail_level == 1 && !in_elseif)
 				ifdef_fail_level = 0;
 			continue;
 		}

 		if (tok == "`elsif") {
 			skip_spaces();
 			std::string name = next_token(true);
 			if (ifdef_fail_level == 0)
 				ifdef_fail_level = 1, in_elseif = true;
 			else if (ifdef_fail_level == 1 && defines_map.count(name) != 0)
 				ifdef_fail_level = 0, in_elseif = true;
 			continue;
 		}

 		if (tok == "`ifdef") {
 			skip_spaces();
 			std::string name = next_token(true);
 			if (ifdef_fail_level > 0 || defines_map.count(name) == 0)
 				ifdef_fail_level++;
 			continue;
 		}

 		if (tok == "`ifndef") {
 			skip_spaces();
 			std::string name = next_token(true);
 			if (ifdef_fail_level > 0 || defines_map.count(name) != 0)
 				ifdef_fail_level++;
 			continue;
 		}

 		if (ifdef_fail_level > 0) {
 			if (tok == "\n")
 				output_code.push_back(tok);
 			continue;
 		}

 		if (tok == "`include") {
 			skip_spaces();
 			std::string fn = next_token(true);
 			while (try_expand_macro(defines_with_args, defines_map, fn)) {
 				fn = next_token();
 			}
 			while (1) {
 				size_t pos = fn.find('"');
 				if (pos == std::string::npos)
 					break;
 				if (pos == 0)
 					fn = fn.substr(1);
 				else
 					fn = fn.substr(0, pos) + fn.substr(pos+1);
 			}
 			std::ifstream ff;
 			ff.clear();
 			std::string fixed_fn = fn;
 			ff.open(fixed_fn.c_str());

 			bool filename_path_sep_found;
 			bool fn_relative;
 #ifdef _WIN32
 			// Both forward and backslash are acceptable separators on Windows.
 			filename_path_sep_found = (filename.find_first_of("/\\") != std::string::npos);
 			// Easier just to invert the check for an absolute path (e.g. C:\ or C:/)
 			fn_relative = !(fn[1] == ':' && (fn[2] == '/' || fn[2] == '\\'));
 #else
 			filename_path_sep_found = (filename.find('/') != std::string::npos);
 			fn_relative = (fn[0] != '/');
 #endif

 			if (ff.fail() && fn.size() > 0 && fn_relative && filename_path_sep_found) {
 				// if the include file was not found, it is not given with an absolute path, and the
 				// currently read file is given with a path, then try again relative to its directory
 				ff.clear();
 #ifdef _WIN32
 				fixed_fn = filename.substr(0, filename.find_last_of("/\\")+1) + fn;
 #else
 				fixed_fn = filename.substr(0, filename.rfind('/')+1) + fn;
 #endif
 				ff.open(fixed_fn);
 			}
 			if (ff.fail() && fn.size() > 0 && fn_relative) {
 				// if the include file was not found and it is not given with an absolute path, then
 				// search it in the include path
 				for (auto incdir : include_dirs) {
 					ff.clear();
 					fixed_fn = incdir + '/' + fn;
 					ff.open(fixed_fn);
 					if (!ff.fail()) break;
 				}
 			}
 			if (ff.fail()) {
 				output_code.push_back("`file_notfound " + fn);
 			} else {
 				input_file(ff, fixed_fn);
 				yosys_input_files.insert(fixed_fn);
 			}
 			continue;
 		}

 		if (tok == "`file_push") {
 			skip_spaces();
 			std::string fn = next_token(true);
 			if (!fn.empty() && fn.front() == '"' && fn.back() == '"')
 				fn = fn.substr(1, fn.size()-2);
 			output_code.push_back(tok + " \"" + fn + "\"");
 			filename_stack.push_back(filename);
 			filename = fn;
 			continue;
 		}

 		if (tok == "`file_pop") {
 			output_code.push_back(tok);
 			filename = filename_stack.back();
 			filename_stack.pop_back();
 			continue;
 		}

 		if (tok == "`define") {
 			std::string name, value;
 			std::map<std::string, int> args;
 			skip_spaces();
 			name = next_token(true);
 			bool here_doc_mode = false;
 			int newline_count = 0;
 			int state = 0;
 			if (skip_spaces() != "")
 				state = 3;
 			while (!tok.empty()) {
 				tok = next_token();
 				if (tok == "\"\"\"") {
 					here_doc_mode = !here_doc_mode;
 					continue;
 				}
 				if (state == 0 && tok == "(") {
 					state = 1;
 					skip_spaces();
 				} else
 				if (state == 1) {
 					if (tok == ")")
 						state = 2;
 					else if (tok != ",") {
 						int arg_idx = args.size()+1;
 						args[tok] = arg_idx;
 					}
 					skip_spaces();
 				} else {
 					if (state != 2)
 						state = 3;
 					if (tok == "\n") {
 						if (here_doc_mode) {
 							value += " ";
 							newline_count++;
 						} else {
 							return_char('\n');
 							break;
 						}
 					} else
 					if (tok == "\\") {
 						char ch = next_char();
 						if (ch == '\n') {
 							value += " ";
 							newline_count++;
 						} else {
 							value += std::string("\\");
 							return_char(ch);
 						}
 					} else
 					if (args.count(tok) > 0)
 						value += stringf("`macro_%s_arg%d", name.c_str(), args.at(tok));
 					else
 						value += tok;
 				}
 			}
 			while (newline_count-- > 0)
 				return_char('\n');
 			if (strchr("abcdefghijklmnopqrstuvwxyz_ABCDEFGHIJKLMNOPQRSTUVWXYZ$0123456789", name[0])) {
 				// printf("define: >>%s<< -> >>%s<<\n", name.c_str(), value.c_str());
 				defines_map[name] = value;
 				if (state == 2)
 					defines_with_args.insert(name);
 				else
 					defines_with_args.erase(name);
 				global_defines_cache[name] = std::pair<std::string, bool>(value, state == 2);
 			} else {
 				log_file_error(filename, 0, "Invalid name for macro definition: >>%s<<.\n", name.c_str());
 			}
 			continue;
 		}

 		if (tok == "`undef") {
 			std::string name;
 			skip_spaces();
 			name = next_token(true);
 			// printf("undef: >>%s<<\n", name.c_str());
 			defines_map.erase(name);
 			defines_with_args.erase(name);
 			global_defines_cache.erase(name);
 			continue;
 		}

 		if (tok == "`timescale") {
 			skip_spaces();
 			while (!tok.empty() && tok != "\n")
 				tok = next_token(true);
 			if (tok == "\n")
 				return_char('\n');
 			continue;
 		}

 		if (tok == "`resetall") {
 			defines_map.clear();
 			defines_with_args.clear();
 			global_defines_cache.clear();
 			continue;
 		}

 		if (try_expand_macro(defines_with_args, defines_map, tok))
 			continue;

 		output_code.push_back(tok);
 	}

 	std::string output;
 	for (auto &str : output_code)
 		output += str;

 	output_code.clear();
 	input_buffer.clear();
 	input_buffer_charp = 0;

 	return output;
 }

 YOSYS_NAMESPACE_END
	/*
	* 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.
	*
	* ---
	*
	* The Verilog frontend.
	*
	* This frontend is using the AST frontend library (see frontends/ast/).
	* Thus this frontend does not generate RTLIL code directly but creates an
	* AST directly from the Verilog parse tree and then passes this AST to
	* the AST frontend library.
	*
	* ---
	*
	* Ad-hoc implementation of a Verilog preprocessor. The directives `define,
	* `include, `ifdef, `ifndef, `else and `endif are handled here. All other
	* directives are handled by the lexer (see lexer.l).
	*
	*/

	#include "verilog_frontend.h"
	#include "kernel/log.h"
	#include <stdarg.h>
	#include <stdio.h>
	#include <string.h>

	YOSYS_NAMESPACE_BEGIN
	using namespace VERILOG_FRONTEND;

	static std::list<std::string> output_code;
	static std::list<std::string> input_buffer;
	static size_t input_buffer_charp;

	static void return_char(char ch)
	{
	if (input_buffer_charp == 0)
	input_buffer.push_front(std::string() + ch);
	else
	input_buffer.front()[--input_buffer_charp] = ch;
	}

	static void insert_input(std::string str)
	{
	if (input_buffer_charp != 0) {
	input_buffer.front() = input_buffer.front().substr(input_buffer_charp);
	input_buffer_charp = 0;
	}
	input_buffer.push_front(str);
	}

	static char next_char()
	{
	if (input_buffer.empty())
	return 0;

	log_assert(input_buffer_charp <= input_buffer.front().size());
	if (input_buffer_charp == input_buffer.front().size()) {
	input_buffer_charp = 0;
	input_buffer.pop_front();
	return next_char();
	}

	char ch = input_buffer.front()[input_buffer_charp++];
	return ch == '\r' ? next_char() : ch;
	}

	static std::string skip_spaces()
	{
	std::string spaces;
	while (1) {
	char ch = next_char();
	if (ch == 0)
	break;
	if (ch != ' ' && ch != '\t') {
	return_char(ch);
	break;
	}
	spaces += ch;
	}
	return spaces;
	}

	static std::string next_token(bool pass_newline = false)
	{
	std::string token;

	char ch = next_char();
	if (ch == 0)
	return token;

	token += ch;
	if (ch == '\n') {
	if (pass_newline) {
	output_code.push_back(token);
	return "";
	}
	return token;
	}

	if (ch == ' ' \|\| ch == '\t')
	{
	while ((ch = next_char()) != 0) {
	if (ch != ' ' && ch != '\t') {
	return_char(ch);
	break;
	}
	token += ch;
	}
	}
	else if (ch == '"')
	{
	while ((ch = next_char()) != 0) {
	token += ch;
	if (ch == '"')
	break;
	if (ch == '\\') {
	if ((ch = next_char()) != 0)
	token += ch;
	}
	}
	if (token == "\"\"" && (ch = next_char()) != 0) {
	if (ch == '"')
	token += ch;
	else
	return_char(ch);
	}
	}
	else if (ch == '/')
	{
	if ((ch = next_char()) != 0) {
	if (ch == '/') {
	token += '*';
	char last_ch = 0;
	while ((ch = next_char()) != 0) {
	if (ch == '\n') {
	return_char(ch);
	break;
	}
	if (last_ch != '*' \|\| ch != '/') {
	token += ch;
	last_ch = ch;
	}
	}
	token += " */";
	}
	else if (ch == '*') {
	token += '*';
	int newline_count = 0;
	char last_ch = 0;
	while ((ch = next_char()) != 0) {
	if (ch == '\n') {
	newline_count++;
	token += ' ';
	} else
	token += ch;
	if (last_ch == '*' && ch == '/')
	break;
	last_ch = ch;
	}
	while (newline_count-- > 0)
	return_char('\n');
	}
	else
	return_char(ch);
	}
	}
	else
	{
	const char *ok = "abcdefghijklmnopqrstuvwxyz_ABCDEFGHIJKLMNOPQRSTUVWXYZ$0123456789";
	if (ch == '`' \|\| strchr(ok, ch) != NULL)
	{
	char first = ch;
	ch = next_char();
	if (first == '`' && (ch == '"' \|\| ch == '`')) {
	token += ch;
	} else do {
	if (strchr(ok, ch) == NULL) {
	return_char(ch);
	break;
	}
	token += ch;
	} while ((ch = next_char()) != 0);
	}
	}
	return token;
	}

	static void input_file(std::istream &f, std::string filename)
	{
	char buffer[513];
	int rc;

	insert_input("");
	auto it = input_buffer.begin();

	input_buffer.insert(it, "`file_push \"" + filename + "\"\n");
	while ((rc = readsome(f, buffer, sizeof(buffer)-1)) > 0) {
	buffer[rc] = 0;
	input_buffer.insert(it, buffer);
	}
	input_buffer.insert(it, "\n`file_pop\n");
	}


	static bool try_expand_macro(std::set<std::string> &defines_with_args,
	std::map<std::string, std::string> &defines_map,
	std::string &tok
	)
	{
	if (tok == "`\"") {
	std::string literal("\"");
	// Expand string literal
	while (!input_buffer.empty()) {
	std::string ntok = next_token();
	if (ntok == "`\"") {
	insert_input(literal+"\"");
	return true;
	} else if (!try_expand_macro(defines_with_args, defines_map, ntok)) {
	literal += ntok;
	}
	}
	return false; // error - unmatched `"
	} else if (tok.size() > 1 && tok[0] == '`' && defines_map.count(tok.substr(1)) > 0) {
	std::string name = tok.substr(1);
	// printf("expand: >>%s<< -> >>%s<<\n", name.c_str(), defines_map[name].c_str());
	std::string skipped_spaces = skip_spaces();
	tok = next_token(false);
	if (tok == "(" && defines_with_args.count(name) > 0) {
	int level = 1;
	std::vector<std::string> args;
	args.push_back(std::string());
	while (1)
	{
	skip_spaces();
	tok = next_token(true);
	if (tok == ")" \|\| tok == "}" \|\| tok == "]")
	level--;
	if (level == 0)
	break;
	if (level == 1 && tok == ",")
	args.push_back(std::string());
	else
	args.back() += tok;
	if (tok == "(" \|\| tok == "{" \|\| tok == "[")
	level++;
	}
	for (int i = 0; i < GetSize(args); i++)
	defines_map[stringf("macro_%s_arg%d", name.c_str(), i+1)] = args[i];
	} else {
	insert_input(tok);
	insert_input(skipped_spaces);
	}
	insert_input(defines_map[name]);
	return true;
	} else if (tok == "``") {
	// Swallow `` in macro expansion
	return true;
	} else return false;
	}

	std::string frontend_verilog_preproc(std::istream &f, std::string filename, const std::map<std::string, std::string> &pre_defines_map,
	dict<std::string, std::pair<std::string, bool>> &global_defines_cache, const std::list<std::string> &include_dirs)
	{
	std::set<std::string> defines_with_args;
	std::map<std::string, std::string> defines_map(pre_defines_map);
	std::vector<std::string> filename_stack;
	int ifdef_fail_level = 0;
	bool in_elseif = false;

	output_code.clear();
	input_buffer.clear();
	input_buffer_charp = 0;

	input_file(f, filename);

	defines_map["YOSYS"] = "1";
	defines_map[formal_mode ? "FORMAL" : "SYNTHESIS"] = "1";

	for (auto &it : pre_defines_map)
	defines_map[it.first] = it.second;

	for (auto &it : global_defines_cache) {
	if (it.second.second)
	defines_with_args.insert(it.first);
	defines_map[it.first] = it.second.first;
	}

	while (!input_buffer.empty())
	{
	std::string tok = next_token();
	// printf("token: >>%s<<\n", tok != "\n" ? tok.c_str() : "NEWLINE");

	if (tok == "`endif") {
	if (ifdef_fail_level > 0)
	ifdef_fail_level--;
	if (ifdef_fail_level == 0)
	in_elseif = false;
	continue;
	}

	if (tok == "`else") {
	if (ifdef_fail_level == 0)
	ifdef_fail_level = 1;
	else if (ifdef_fail_level == 1 && !in_elseif)
	ifdef_fail_level = 0;
	continue;
	}

	if (tok == "`elsif") {
	skip_spaces();
	std::string name = next_token(true);
	if (ifdef_fail_level == 0)
	ifdef_fail_level = 1, in_elseif = true;
	else if (ifdef_fail_level == 1 && defines_map.count(name) != 0)
	ifdef_fail_level = 0, in_elseif = true;
	continue;
	}

	if (tok == "`ifdef") {
	skip_spaces();
	std::string name = next_token(true);
	if (ifdef_fail_level > 0 \|\| defines_map.count(name) == 0)
	ifdef_fail_level++;
	continue;
	}

	if (tok == "`ifndef") {
	skip_spaces();
	std::string name = next_token(true);
	if (ifdef_fail_level > 0 \|\| defines_map.count(name) != 0)
	ifdef_fail_level++;
	continue;
	}

	if (ifdef_fail_level > 0) {
	if (tok == "\n")
	output_code.push_back(tok);
	continue;
	}

	if (tok == "`include") {
	skip_spaces();
	std::string fn = next_token(true);
	while (try_expand_macro(defines_with_args, defines_map, fn)) {
	fn = next_token();
	}
	while (1) {
	size_t pos = fn.find('"');
	if (pos == std::string::npos)
	break;
	if (pos == 0)
	fn = fn.substr(1);
	else
	fn = fn.substr(0, pos) + fn.substr(pos+1);
	}
	std::ifstream ff;
	ff.clear();
	std::string fixed_fn = fn;
	ff.open(fixed_fn.c_str());

	bool filename_path_sep_found;
	bool fn_relative;
	#ifdef _WIN32
	// Both forward and backslash are acceptable separators on Windows.
	filename_path_sep_found = (filename.find_first_of("/\\") != std::string::npos);
	// Easier just to invert the check for an absolute path (e.g. C:\ or C:/)
	fn_relative = !(fn[1] == ':' && (fn[2] == '/' \|\| fn[2] == '\\'));
	#else
	filename_path_sep_found = (filename.find('/') != std::string::npos);
	fn_relative = (fn[0] != '/');
	#endif

	if (ff.fail() && fn.size() > 0 && fn_relative && filename_path_sep_found) {
	// if the include file was not found, it is not given with an absolute path, and the
	// currently read file is given with a path, then try again relative to its directory
	ff.clear();
	#ifdef _WIN32
	fixed_fn = filename.substr(0, filename.find_last_of("/\\")+1) + fn;
	#else
	fixed_fn = filename.substr(0, filename.rfind('/')+1) + fn;
	#endif
	ff.open(fixed_fn);
	}
	if (ff.fail() && fn.size() > 0 && fn_relative) {
	// if the include file was not found and it is not given with an absolute path, then
	// search it in the include path
	for (auto incdir : include_dirs) {
	ff.clear();
	fixed_fn = incdir + '/' + fn;
	ff.open(fixed_fn);
	if (!ff.fail()) break;
	}
	}
	if (ff.fail()) {
	output_code.push_back("`file_notfound " + fn);
	} else {
	input_file(ff, fixed_fn);
	yosys_input_files.insert(fixed_fn);
	}
	continue;
	}

	if (tok == "`file_push") {
	skip_spaces();
	std::string fn = next_token(true);
	if (!fn.empty() && fn.front() == '"' && fn.back() == '"')
	fn = fn.substr(1, fn.size()-2);
	output_code.push_back(tok + " \"" + fn + "\"");
	filename_stack.push_back(filename);
	filename = fn;
	continue;
	}

	if (tok == "`file_pop") {
	output_code.push_back(tok);
	filename = filename_stack.back();
	filename_stack.pop_back();
	continue;
	}

	if (tok == "`define") {
	std::string name, value;
	std::map<std::string, int> args;
	skip_spaces();
	name = next_token(true);
	bool here_doc_mode = false;
	int newline_count = 0;
	int state = 0;
	if (skip_spaces() != "")
	state = 3;
	while (!tok.empty()) {
	tok = next_token();
	if (tok == "\"\"\"") {
	here_doc_mode = !here_doc_mode;
	continue;
	}
	if (state == 0 && tok == "(") {
	state = 1;
	skip_spaces();
	} else
	if (state == 1) {
	if (tok == ")")
	state = 2;
	else if (tok != ",") {
	int arg_idx = args.size()+1;
	args[tok] = arg_idx;
	}
	skip_spaces();
	} else {
	if (state != 2)
	state = 3;
	if (tok == "\n") {
	if (here_doc_mode) {
	value += " ";
	newline_count++;
	} else {
	return_char('\n');
	break;
	}
	} else
	if (tok == "\\") {
	char ch = next_char();
	if (ch == '\n') {
	value += " ";
	newline_count++;
	} else {
	value += std::string("\\");
	return_char(ch);
	}
	} else
	if (args.count(tok) > 0)
	value += stringf("`macro_%s_arg%d", name.c_str(), args.at(tok));
	else
	value += tok;
	}
	}
	while (newline_count-- > 0)
	return_char('\n');
	if (strchr("abcdefghijklmnopqrstuvwxyz_ABCDEFGHIJKLMNOPQRSTUVWXYZ$0123456789", name[0])) {
	// printf("define: >>%s<< -> >>%s<<\n", name.c_str(), value.c_str());
	defines_map[name] = value;
	if (state == 2)
	defines_with_args.insert(name);
	else
	defines_with_args.erase(name);
	global_defines_cache[name] = std::pair<std::string, bool>(value, state == 2);
	} else {
	log_file_error(filename, 0, "Invalid name for macro definition: >>%s<<.\n", name.c_str());
	}
	continue;
	}

	if (tok == "`undef") {
	std::string name;
	skip_spaces();
	name = next_token(true);
	// printf("undef: >>%s<<\n", name.c_str());
	defines_map.erase(name);
	defines_with_args.erase(name);
	global_defines_cache.erase(name);
	continue;
	}

	if (tok == "`timescale") {
	skip_spaces();
	while (!tok.empty() && tok != "\n")
	tok = next_token(true);
	if (tok == "\n")
	return_char('\n');
	continue;
	}

	if (tok == "`resetall") {
	defines_map.clear();
	defines_with_args.clear();
	global_defines_cache.clear();
	continue;
	}

	if (try_expand_macro(defines_with_args, defines_map, tok))
	continue;

	output_code.push_back(tok);
	}

	std::string output;
	for (auto &str : output_code)
	output += str;

	output_code.clear();
	input_buffer.clear();
	input_buffer_charp = 0;

	return output;
	}

	YOSYS_NAMESPACE_END